Exogenous γ-aminobutyric acid (GABA) affects pollen tube growth via modulating putative Ca2+-permeable membrane channels and is coupled to negative regulation on glutamate decarboxylase

PubMed Central

Yu, Guang-Hui; Zou, Jie; Feng, Jing; Peng, Xiong-Bo; Wu, Ju-You; Wu, Ying-Liang; Palanivelu, Ravishankar; Sun, Meng-Xiang

2014-01-01

γ-Aminobutyric acid (GABA) is implicated in pollen tube growth, but the molecular and cellular mechanisms that it mediates are largely unknown. Here, it is shown that exogenous GABA modulates putative Ca2+-permeable channels on the plasma membranes of tobacco pollen grains and pollen tubes. Whole-cell voltage-clamp experiments and non-invasive micromeasurement technology (NMT) revealed that the influx of Ca2+ increases in pollen tubes in response to exogenous GABA. It is also demonstrated that glutamate decarboxylase (GAD), the rate-limiting enzyme of GABA biosynthesis, is involved in feedback controls of Ca2+-permeable channels to fluctuate intracellular GABA levels and thus modulate pollen tube growth. The findings suggest that GAD activity linked with Ca2+-permeable channels relays an extracellular GABA signal and integrates multiple signal pathways to modulate tobacco pollen tube growth. Thus, the data explain how GABA mediates the communication between the style and the growing pollen tubes. PMID:24799560

Plant transformation via pollen tube-mediated gene transfer

USDA-ARS?s Scientific Manuscript database

Genetic transformation using foreign genes and the subsequent development of transgenic plants has been employed to develop enhanced elite germplasm. Although some skepticism exits regarding pollen tube-mediated gene transfer (PTT), reports demonstrating improved transformation efficiency with PTT ...

Receptor-like kinases as surface regulators for RAC/ROP-mediated pollen tube growth and interaction with the pistil

PubMed Central

Zou, Yanjiao; Aggarwal, Mini; Zheng, Wen-Guang; Wu, Hen-Ming; Cheung, Alice Y.

2011-01-01

Background RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen tubes depend on continuous interactions with an extracellular environment produced by their surrounding tissues as they grow within the female organ pistil to deliver sperm to the female gametophyte for fertilization. Scope We review studies on pollen tube growth that provide compelling evidence indicating that RAC/ROPs are crucial for regulating the cellular processes that underlie the polarized cell growth process. Efforts to identify cell surface regulators that mediate extracellular signals also point to RAC/ROPs being the molecular switches targeted by growth-regulating female factors for modulation to mediate pollination and fertilization. We discuss a large volume of work spanning more than two decades on a family of pollen-specific receptor kinases and some recent studies on members of the FERONIA family of receptor-like kinases (RLKs). Significance The research described shows the crucial roles that two RLK families play in transducing signals from growth regulatory factors to the RAC/ROP switch at the pollen tube apex to mediate and target pollen tube growth to the female gametophyte and signal its disintegration to achieve fertilization once inside the female chamber. PMID:22476487

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

PubMed

Jhala, A J; Bhatt, H; Topinka, K; Hall, L M

2011-04-01

Coexistence allows growers and consumers the choice of producing or purchasing conventional or organic crops with known standards for adventitious presence of genetically engineered (GE) seed. Flax (Linum usitatissimum L.) is multipurpose oilseed crop in which product diversity and utility could be enhanced for industrial, nutraceutical and pharmaceutical markets through genetic engineering. If GE flax were released commercially, pollen-mediated gene flow will determine in part whether GE flax could coexist without compromising other markets. As a part of pre-commercialization risk assessment, we quantified pollen-mediated gene flow between two cultivars of flax. Field experiments were conducted at four locations during 2006 and 2007 in western Canada using a concentric donor (20 × 20 m) receptor (120 × 120 m) design. Gene flow was detected through the xenia effect of dominant alleles of high α-linolenic acid (ALA; 18:3(cisΔ9,12,15)) to the low ALA trait. Seeds were harvested from the pollen recipient plots up to a distance of 50 m in eight directions from the pollen donor. High ALA seeds were identified using a thiobarbituric acid test and served as a marker for gene flow. Binomial distribution and power analysis were used to predict the minimum number of seeds statistically required to detect the frequency of gene flow at specific α (confidence interval) and power (1-β) values. As a result of the low frequency of gene flow, approximately 4 million seeds were screened to derive accurate quantification. Frequency of gene flow was highest near the source: averaging 0.0185 at 0.1 m but declined rapidly with distance, 0.0013 and 0.00003 at 3 and 35 m, respectively. Gene flow was reduced to 50% (O₅₀) and 90% (O₉₀) between 0.85 to 2.64 m, and 5.68 to 17.56 m, respectively. No gene flow was detected at any site or year > 35 m distance from the pollen source, suggesting that frequency of gene flow was ≤ 0.00003 (P = 0.95). Although it is not possible to eliminate all adventitious presence caused by pollen-mediated gene flow, through harvest blending and the use of buffer zones between GE and conventional flax fields, it could be minimized. Managing other sources of adventitious presence including seed mixing and volunteer populations may be more problematic.

The Arabidopsis KINβγ Subunit of the SnRK1 Complex Regulates Pollen Hydration on the Stigma by Mediating the Level of Reactive Oxygen Species in Pollen

PubMed Central

Zhao, Ting Ting; Li, Fei; Jia, Xiao Na; Zhao, Xin-Ying; Zhang, Xian Sheng

2016-01-01

Pollen–stigma interactions are essential for pollen germination. The highly regulated process of pollen germination includes pollen adhesion, hydration, and germination on the stigma. However, the internal signaling of pollen that regulates pollen–stigma interactions is poorly understood. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex which plays important roles in the regulation of plant development. Here, we showed that KINβγ was a cytoplasm- and nucleus-localized protein in the vegetative cells of pollen grains in Arabidopsis. The pollen of the Arabidopsis kinβγ mutant could not germinate on stigma, although it germinated normally in vitro. Further analysis revealed the hydration of kinβγ mutant pollen on the stigma was compromised. However, adding water to the stigma promoted the germination of the mutant pollen in vivo, suggesting that the compromised hydration of the mutant pollen led to its defective germination. In kinβγ mutant pollen, the structure of the mitochondria and peroxisomes was destroyed, and their numbers were significantly reduced compared with those in the wild type. Furthermore, we found that the kinβγ mutant exhibited reduced levels of reactive oxygen species (ROS) in pollen. The addition of H2O2 in vitro partially compensated for the reduced water absorption of the mutant pollen, and reducing ROS levels in pollen by overexpressing Arabidopsis CATALASE 3 resulted in compromised hydration of pollen on the stigma. These results indicate that Arabidopsis KINβγ is critical for the regulation of ROS levels by mediating the biogenesis of mitochondria and peroxisomes in pollen, which is required for pollen–stigma interactions during pollination. PMID:27472382

Low molecular weight components of pollen alter bronchial epithelial barrier functions.

PubMed

Blume, Cornelia; Swindle, Emily J; Gilles, Stefanie; Traidl-Hoffmann, Claudia; Davies, Donna E

2015-01-01

The bronchial epithelium plays a key role in providing a protective barrier against many environmental substances of anthropogenic or natural origin which enter the lungs during breathing. Appropriate responses to these agents are critical for regulation of tissue homeostasis, while inappropriate responses may contribute to disease pathogenesis. Here, we compared epithelial barrier responses to different pollen species, characterized the active pollen components and the signaling pathways leading to epithelial activation. Polarized bronchial cells were exposed to extracts of timothy grass (Phleum pratense), ragweed (Ambrosia artemisifolia), mugwort (Artemisia vulgaris), birch (Betula alba) and pine (Pinus sylvestris) pollens. All pollen species caused a decrease in ionic permeability as monitored trans-epithelial electrical resistance (TER) and induced polarized release of mediators analyzed by ELISA, with grass pollen showing the highest activity. Ultrafiltration showed that the responses were due to components <3kDa. However, lipid mediators, including phytoprostane E1, had no effect on TER, and caused only modest induction of mediator release. Reverse-phase chromatography separated 2 active fractions: the most hydrophilic maximally affected cytokine release whereas the other only affected TER. Inhibitor studies revealed that JNK played a more dominant role in regulation of barrier permeability in response to grass pollen exposure, whereas ERK and p38 controlled cytokine release. Adenosine and the flavonoid isorhamnetin present in grass pollen contributed to the overall effect on airway epithelial barrier responses. In conclusion, bronchial epithelial barrier functions are differentially affected by several low molecular weight components released by pollen. Furthermore, ionic permeability and innate cytokine production are differentially regulated.

Soy allergy in perspective.

PubMed

Ballmer-Weber, Barbara K; Vieths, Stefan

2008-06-01

The purpose of this paper is to review and discuss studies on soy allergy. In Central Europe soy is a clinically relevant birch pollen-related allergenic food. Crossreaction is mediated by a Bet v 1 homologous protein, Gly m 4. Additionally, birch pollen allergic patients might acquire through Bet v 1 sensitization allergies to mungbean or peanut, in which Vig r 1 and Ara h 8 are the main cross-reactive allergens. Threshold doses in soy allergic individuals range from 10 mg to 50 g of soy and are more than one order of magnitude higher than in peanut allergy. No evidence was found for increased allergenicity of genetically modified soybeans. In Europe, both primary and pollen-related food allergy exist. The diagnosis of legume allergy in birch pollen-sensitized patients should not be excluded on a negative IgE testing to legume extracts. Bet v 1 related allergens are often underrepresented in extracts. Gly m 4 from soy and Ara h 8 from peanut are nowadays commercially available and are recommended in birch pollen allergic patients with suspicion of soy or peanut allergy, but negative extract-based diagnostic tests to screen for IgE specific to these recombinant allergens.

Extensive long-distance pollen dispersal in a fragmented landscape maintains genetic diversity in white spruce.

PubMed

O'Connell, Lisa M; Mosseler, Alex; Rajora, Om P

2007-01-01

Conifers are among the most genetically diverse plants but show the lowest levels of genetic differentiation, even among geographically distant populations. High gene flow among populations may be one of the most important factors in maintaining these genetic patterns. Here, we provide empirical evidence for extensive pollen-mediated gene dispersal between natural stands of a widespread northern temperate/boreal conifer, Picea glauca. We used 6 polymorphic allozyme loci to quantify the proportion of seeds sired by pollen originating from different sources in a landscape fragmented by agriculture in North Central Ontario, Canada. In 7 stands, a small proportion of seeds were sired by self-pollen or neighboring trees but 87.1% (+/-1.7% standard error [SE]) of seeds were sired by pollen from at least 250 to 3000 m away. In 4 single isolated trees, self-fertilization rates were low and more than 96% (+/-1.3% SE) of seeds were sired by immigrant pollen. The average minimum pollen dispersal distance in outcrossed matings was 619 m. These results provide strong evidence that extensive long-distance pollen dispersal plays a primary role in maintaining low genetic differentiation among natural populations of P. glauca and helps maintain genetic diversity and minimize inbreeding in small stands in a fragmented landscape.

PLC-Mediated Signaling Pathway in Pollen Tubes Regulates the Gametophytic Self-incompatibility of Pyrus Species

PubMed Central

Qu, Haiyong; Guan, Yaqin; Wang, Yongzhang; Zhang, Shaolin

2017-01-01

Among the Rosaceae species, the gametophytic self-incompatibility (GSI) is controlled by a single multi-allelic S locus, which is composed of the pistil-S and pollen-S genes. The pistil-S gene encodes a polymorphic ribonuclease (S-RNase), which is essential for identifying self-pollen. However, the S-RNase system has not been fully characterized. In this study, the self-S-RNase inhibited the Ca2+-permeable channel activity at pollen tube apices and the selectively decreased phospholipase C (PLC) activity in the plasma membrane of Pyrus pyrifolia pollen tubes. Self-S-RNase decreased the Ca2+ influx through a PLC-mediated signaling pathway. Phosphatidylinositol-specific PLC has a 26-amino acid insertion in pollen tubes of the ‘Jinzhuili’ cultivar, which is a spontaneous self-compatible mutant of the ‘Yali’ cultivar. ‘Yali’ plants exhibit a typical S-RNase-based GSI. Upon self-pollination, PLC gene expression is significantly higher in ‘Jinzhuili’ pollen tubes than that in ‘Yali’ pollen tubes. Moreover, the PLC in pollen tubes can only interact with one of the two types of S-RNase from the style. In the Pyrus x bretschneideri Rehd, the PLC directly interacted with the S7-RNase in the pollen tube, but not with the S34-RNase. Collectively, our results reveal that the effects of S-RNase on PLC activity are required for S-specific pollen rejection, and that PLC-IP3 participates in the self-incompatibility reaction of Pyrus species. PMID:28729872

PLC-Mediated Signaling Pathway in Pollen Tubes Regulates the Gametophytic Self-incompatibility of Pyrus Species.

PubMed

Qu, Haiyong; Guan, Yaqin; Wang, Yongzhang; Zhang, Shaolin

2017-01-01

Among the Rosaceae species, the gametophytic self-incompatibility (GSI) is controlled by a single multi-allelic S locus, which is composed of the pistil-S and pollen-S genes. The pistil-S gene encodes a polymorphic ribonuclease (S-RNase), which is essential for identifying self-pollen. However, the S-RNase system has not been fully characterized. In this study, the self-S-RNase inhibited the Ca 2+ -permeable channel activity at pollen tube apices and the selectively decreased phospholipase C ( PLC ) activity in the plasma membrane of Pyrus pyrifolia pollen tubes. Self-S-RNase decreased the Ca 2+ influx through a PLC -mediated signaling pathway. Phosphatidylinositol-specific PLC has a 26-amino acid insertion in pollen tubes of the 'Jinzhuili' cultivar, which is a spontaneous self-compatible mutant of the 'Yali' cultivar. 'Yali' plants exhibit a typical S-RNase-based GSI. Upon self-pollination, PLC gene expression is significantly higher in 'Jinzhuili' pollen tubes than that in 'Yali' pollen tubes. Moreover, the PLC in pollen tubes can only interact with one of the two types of S-RNase from the style. In the Pyrus x bretschneideri Rehd, the PLC directly interacted with the S 7 -RNase in the pollen tube, but not with the S 34 -RNase. Collectively, our results reveal that the effects of S-RNase on PLC activity are required for S-specific pollen rejection, and that PLC -IP 3 participates in the self-incompatibility reaction of Pyrus species.

Leptokurtic pollen-flow, non-leptokurtic gene-flow in a wind-pollinated herb, Plantago lanceolata L.

PubMed

Tonsor, Stephen J

1985-10-01

The purpose of this study was to simultaneously measure pollen dispersal distance and actual pollen-mediated gene-flow distance in a wind-pollinated herb, Plantago lanceolata. The pollen dispersal distribution, measured as pollen deposition in a wind tunnel, is leptokurtic, as expected from previous studies of wind-pollinated plants. Gene-flow, measured as seeds produced on rows of male-sterile inflorescences in the wind tunnel, is non-leptokurtic, peaking at an intermediate distance. The difference between the two distributions results from the tendency of the pollen grains to cluster. These pollen clusters are the units of gene dispersal, with clusters of intermediate and large size contributing disproportionately to gene-flow. Since many wind-pollinated species show pollen clustering (see text), the common assumption for wind-pollinated plants that gene-flow is leptokurtic requires re-examination. Gene-flow was also measured in an artifical outdoor population of male-steriles, containing a single pollen source plant in the center of the array. The gene flow distribution is significantly platykurtic, and has the same general properties outdoors, where wind speed and turbulence are uncontrolled, as it does in the wind tunnel. I estimated genetic neighborhood size based on my measure of gene-flow in the outdoor population. The estimate shows that populations of Plantago lanceolata will vary in effective number from a few tens of plants to more than five hundred plants, depending on the density of the population in question. Thus, the measured pollen-mediated gene-flow distribution and population density will interact to produce effective population sizes ranging from those in which there is no random genetic drift to those in which random genetic drift plays an important role in determining gene frequencies within and among populations. Despite the platykurtosis in the distribution, pollen-mediated gene dispersal distances are still quite limited, and considerable within and among-population genetic differentiation is to be expected in this species.

Variation of the group 5 grass pollen allergen content of airborne pollen in relation to geographic location and time in season.

PubMed

Buters, Jeroen; Prank, Marje; Sofiev, Mikhail; Pusch, Gudrun; Albertini, Roberto; Annesi-Maesano, Isabella; Antunes, Celia; Behrendt, Heidrun; Berger, Uwe; Brandao, Rui; Celenk, Sevcan; Galan, Carmen; Grewling, Łukasz; Jackowiak, Bogdan; Kennedy, Roy; Rantio-Lehtimäki, Auli; Reese, Gerald; Sauliene, Ingrida; Smith, Matt; Thibaudon, Michel; Weber, Bernhard; Cecchi, Lorenzo

2015-07-01

Allergies to grass pollen are the number one cause of outdoor hay fever. The human immune system reacts with symptoms to allergen from pollen. We investigated the natural variability in release of the major group 5 allergen from grass pollen across Europe. Airborne pollen and allergens were simultaneously collected daily with a volumetric spore trap and a high-volume cascade impactor at 10 sites across Europe for 3 consecutive years. Group 5 allergen levels were determined with a Phl p 5-specific ELISA in 2 fractions of ambient air: particulate matter of greater than 10 μm in diameter and particulate matter greater than 2.5 μm and less than 10 μm in diameter. Mediator release by ambient air was determined in FcεRI-humanized basophils. The origin of pollen was modeled and condensed to pollen potency maps. On average, grass pollen released 2.3 pg of Phl p 5 per pollen. Allergen release per pollen (potency) varied substantially, ranging from less than 1 to 9 pg of Phl p 5 per pollen (5% to 95% percentile). The main variation was locally day to day. Average potency maps across Europe varied between years. Mediator release from basophilic granulocytes correlated better with allergen levels per cubic meter (r(2) = 0.80, P < .001) than with pollen grains per cubic meter (r(2) = 0.61, P < .001). In addition, pollen released different amounts of allergen in the non-pollen-bearing fraction of ambient air, depending on humidity. Across Europe, the same amount of pollen released substantially different amounts of group 5 grass pollen allergen. This variation in allergen release is in addition to variations in pollen counts. Molecular aerobiology (ie, determining allergen in ambient air) might be a valuable addition to pollen counting. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Floral traits mediate the vulnerability of aloes to pollen theft and inefficient pollination by bees

PubMed Central

Hargreaves, Anna L.; Harder, Lawrence D.; Johnson, Steven D.

2012-01-01

Background and Aims Pollen-collecting bees are among the most important pollinators globally, but are also the most common pollen thieves and can significantly reduce plant reproduction. The pollination efficiency of pollen collectors depends on the frequency of their visits to female(-phase) flowers, contact with stigmas and deposition of pollen of sufficient quantity and quality to fertilize ovules. Here we investigate the relative importance of these components, and the hypothesis that floral and inflorescence characteristics mediate the pollination role of pollen collection by bees. Methods For ten Aloe species that differ extensively in floral and inflorescence traits, we experimentally excluded potential bird pollinators to quantify the contributions of insect visitors to pollen removal, pollen deposition and seed production. We measured corolla width and depth to determine nectar accessibility, and the phenology of anther dehiscence and stigma receptivity to quantify herkogamy and dichogamy. Further, we compiled all published bird-exclusion studies of aloes, and compared insect pollination success with floral morphology. Key Results Species varied from exclusively insect pollinated, to exclusively bird pollinated but subject to extensive pollen theft by insects. Nectar inaccessibility and strong dichogamy inhibited pollination by pollen-collecting bees by discouraging visits to female-phase (i.e. pollenless) flowers. For species with large inflorescences of pollen-rich flowers, pollen collectors successfully deposited pollen, but of such low quality (probably self-pollen) that they made almost no contribution to seed set. Indeed, considering all published bird-exclusion studies (17 species in total), insect pollination efficiency varied significantly with floral shape. Conclusions Species-specific floral and inflorescence characteristics, especially nectar accessibility and dichogamy, control the efficiency of pollen-collecting bees as pollinators of aloes. PMID:22278414

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

PubMed Central

Jhala, A J; Bhatt, H; Topinka, K; Hall, L M

2011-01-01

Coexistence allows growers and consumers the choice of producing or purchasing conventional or organic crops with known standards for adventitious presence of genetically engineered (GE) seed. Flax (Linum usitatissimum L.) is multipurpose oilseed crop in which product diversity and utility could be enhanced for industrial, nutraceutical and pharmaceutical markets through genetic engineering. If GE flax were released commercially, pollen-mediated gene flow will determine in part whether GE flax could coexist without compromising other markets. As a part of pre-commercialization risk assessment, we quantified pollen-mediated gene flow between two cultivars of flax. Field experiments were conducted at four locations during 2006 and 2007 in western Canada using a concentric donor (20 × 20 m) receptor (120 × 120 m) design. Gene flow was detected through the xenia effect of dominant alleles of high α-linolenic acid (ALA; 18:3cisΔ9,12,15) to the low ALA trait. Seeds were harvested from the pollen recipient plots up to a distance of 50 m in eight directions from the pollen donor. High ALA seeds were identified using a thiobarbituric acid test and served as a marker for gene flow. Binomial distribution and power analysis were used to predict the minimum number of seeds statistically required to detect the frequency of gene flow at specific α (confidence interval) and power (1−β) values. As a result of the low frequency of gene flow, approximately 4 million seeds were screened to derive accurate quantification. Frequency of gene flow was highest near the source: averaging 0.0185 at 0.1 m but declined rapidly with distance, 0.0013 and 0.00003 at 3 and 35 m, respectively. Gene flow was reduced to 50% (O50) and 90% (O90) between 0.85 to 2.64 m, and 5.68 to 17.56 m, respectively. No gene flow was detected at any site or year >35 m distance from the pollen source, suggesting that frequency of gene flow was ⩽0.00003 (P=0.95). Although it is not possible to eliminate all adventitious presence caused by pollen-mediated gene flow, through harvest blending and the use of buffer zones between GE and conventional flax fields, it could be minimized. Managing other sources of adventitious presence including seed mixing and volunteer populations may be more problematic. PMID:20551976

Global warming and allergy in Asia Minor.

PubMed

Bajin, Munir Demir; Cingi, Cemal; Oghan, Fatih; Gurbuz, Melek Kezban

2013-01-01

The earth is warming, and it is warming quickly. Epidemiological studies have demonstrated that global warming is correlated with the frequency of pollen-induced respiratory allergy and allergic diseases. There is a body of evidence suggesting that the prevalence of allergic diseases induced by pollens is increasing in developed countries, a trend that is also evident in the Mediterranean area. Because of its mild winters and sunny days with dry summers, the Mediterranean area is different from the areas of central and northern Europe. Classical examples of allergenic pollen-producing plants of the Mediterranean climate include Parietaria, Olea and Cupressaceae. Asia Minor is a Mediterranean region that connects Asia and Europe, and it includes considerable coastal areas. Gramineae pollens are the major cause of seasonal allergic rhinitis in Asia Minor, affecting 1.3-6.4 % of the population, in accordance with other European regions. This article emphasizes the importance of global climate change and anticipated increases in the prevalence and severity of allergic disease in Asia Minor, mediated through worsening air pollution and altered local and regional pollen production, from an otolaryngologic perspective.

Molecular cloning and characterization of a birch pollen minor allergen, Bet v 5, belonging to a family of isoflavone reductase-related proteins.

PubMed

Karamloo, F; Schmitz, N; Scheurer, S; Foetisch, K; Hoffmann, A; Haustein, D; Vieths, S

1999-11-01

Birch pollen is a major cause of pollinosis and is responsible for cross-reactive oral allergies to fruits, nuts, and vegetables. The major allergen, Bet v 1, has been extensively characterized, and 3 minor allergens, Bet v 2, Bet v 3, and Bet v 4, have been cloned and sequenced. Recently, another birch pollen protein with an apparent mass of 35 kd was described as a new IgE-binding protein in birch pollen with cross-reacting homologues in plant foods. The aim of this study was to determine the primary structure of the 35-kd birch pollen allergen and to investigate its immunologic properties. On the basis of a known complementary DNA fragment, a PCR strategy was applied to obtain the full-length nucleotide sequence of the coding region. The protein was expressed as His-Tag fusion protein in Escherichia coli and purified by Ni-chelate affinity chromatography. Nonfusion protein was obtained by cyanogen bromide treatment of the fusion protein. IgE-binding characteristics and potential allergenicity were investigated by immunoblot, immunoblot inhibition analysis, rat basophil leukemia-cell mediator release assay, and basophil histamine release and compared with those of natural (n) Bet v 5, recombinant (r)Bet v 1, and rBet v 2. Recombinant Bet v 5 has a mass of 33 kd, an isoelectric point of 9.0, and sequence identity of 60% to 80% to isoflavone reductase homologue proteins from various plants. On immunoblots the recombinant Bet v 5 bound IgE from 9 (32%) of 28 sera from patients allergic to birch pollen with a CAP class of at least 3; Bet v 1 was detected by 89% of these patients. IgE immunoblot and inhibition experiments showed that nBet v 5 and rBet v 5 shared identical epitopes. A rabbit antiserum raised against pea isoflavone reductase and patients' IgE reacted with Bet v 5 and proteins of similar size in several vegetable foods, including exotic fruits. A similar reaction pattern was obtained with 2 Bet v 5-specific mAbs. Furthermore, Bet v 5 triggered a dose-dependent mediator release from rat basophil leukemia 2H3 cells passively sensitized with murine anti-birch pollen IgE and from basophils of a Bet v 5-reactive subject with birch pollen allergy. In contrast, no mediator release could be induced from basophils of a subject who was monosensitized to Bet v 1. This 33-kd protein, designated as Bet v 5, is a new minor allergen in birch pollen and may be responsible for pollen-related oral allergy to specific foods in a minority of patients with birch pollen allergy. Amino acid sequence comparison and immunoreactivity to anti-isoflavone reductase serum indicate that Bet v 5 is related to isoflavone reductase, a protein family that is involved in plant defense reactions.

Arabidopsis adaptor protein 1G is critical for pollen development.

PubMed

Feng, Chong; Wang, Jia-Gang; Liu, Hai-Hong; Li, Sha; Zhang, Yan

2017-09-01

Pollen development is a pre-requisite for sexual reproduction of angiosperms, during which various cellular activities are involved. Pollen development accompanies dynamic remodeling of vacuoles through fission and fusion, disruption of which often compromises pollen viability. We previously reported that the Y subunit of adaptor protein 1 (AP1G) mediates synergid degeneration during pollen tube reception. Here, we demonstrate that AP1G is essential for pollen development. AP1G loss-of-function resulted in male gametophytic lethality due to defective pollen development. By ultrastructural analysis and fluorescence labeling, we demonstrate that AP1G loss-of-function compromised dynamic vacuolar remodeling during pollen development and impaired vacuolar acidification of pollen. Results presented here support a key role of vacuoles in gametophytic pollen development. © 2017 Institute of Botany, Chinese Academy of Sciences.

SIPP, a Novel Mitochondrial Phosphate Carrier, Mediates in Self-Incompatibility1[OPEN

PubMed Central

2017-01-01

In Solanaceae, the S-specific interaction between the pistil S-RNase and the pollen S-Locus F-box protein controls self-incompatibility (SI). Although this interaction defines the specificity of the pollen rejection response, the identification of three pistil essential modifier genes unlinked to the S-locus (HT-B, 120K, and NaStEP) unveils a higher degree of complexity in the pollen rejection pathway. We showed previously that NaStEP, a stigma protein with homology with Kunitz-type protease inhibitors, is essential to SI in Nicotiana spp. During pollination, NaStEP is taken up by pollen tubes, where potential interactions with pollen tube proteins might underlie its function. Here, we identified NaSIPP, a mitochondrial protein with phosphate transporter activity, as a novel NaStEP-interacting protein. Coexpression of NaStEP and NaSIPP in pollen tubes showed interaction in the mitochondria, although when expressed alone, NaStEP remains mostly cytosolic, implicating NaSIPP-mediated translocation of NaStEP into the organelle. The NaSIPP transcript is detected specifically in mature pollen of Nicotiana spp.; however, in self-compatible plants, this gene has accumulated mutations, so its coding region is unlikely to produce a functional protein. RNA interference suppression of NaSIPP in Nicotiana spp. pollen grains disrupts the SI by preventing pollen tube inhibition. Taken together, our results are consistent with a model whereby the NaStEP and NaSIPP interaction, in incompatible pollen tubes, might destabilize the mitochondria and contribute to arrest pollen tube growth. PMID:28874520

A pollen-specific calmodulin-binding protein, NPG1, interacts with putative pectate lyases.

PubMed

Shin, Sung-Bong; Golovkin, Maxim; Reddy, Anireddy S N

2014-06-12

Previous genetic studies have revealed that a pollen-specific calmodulin-binding protein, No Pollen Germination 1 (NPG1), is required for pollen germination. However, its mode of action is unknown. Here we report direct interaction of NPG1 with pectate lyase-like proteins (PLLs). A truncated form of AtNPG1 lacking the N-terminal tetratricopeptide repeat 1 (TPR1) failed to interact with PLLs, suggesting that it is essential for NPG1 interaction with PLLs. Localization studies with AtNPG1 fused to a fluorescent reporter driven by its native promoter revealed its presence in the cytosol and cell wall of the pollen grain and the growing pollen tube of plasmolyzed pollen. Together, our data suggest that the function of NPG1 in regulating pollen germination is mediated through its interaction with PLLs, which may modify the pollen cell wall and regulate pollen tube emergence and growth.

Interaction Between Air Pollutants and Pollen Grains: The Role on the Rising Trend in Allergy

PubMed Central

Sedghy, Farnaz; Varasteh, Abdol-Reza; Sankian, Mojtaba; Moghadam, Malihe

2018-01-01

Asthma and allergic diseases cases have risen in recent decades. Plant pollen is considered as the main aeroallergen causing allergic reactions. According to available data, urban residents experience more respiratory allergies than rural residents mainly due to the interaction between chemical air pollutants and pollen grains. This interaction can occur through several mechanisms; chemical pollutants might facilitate pollen allergen release, act as adjuvants to stimulate IgE-mediated responses, modify allergenic potential, and enhance the expression of some allergens in pollen grains. This review focuses on the most recent theories explaining how air pollutants can interact with pollen grains and allergens. PMID:29766006

Feral rice from introgression of weedy rice genes into transgenic herbicide-resistant hybrid-rice progeny.

PubMed

Zhang, Jingxu; Kang, Ye; Valverde, Bernal E; Dai, Weimin; Song, Xiaoling; Qiang, Sheng

2018-06-05

Pollen-mediated herbicide-resistance transgene flow occurs bidirectionally between transgenic cultivated rice and weedy rice. The potential risk of weedy traits introgressing into hybrid rice is underestimated and poorly understood. Two of each glufosinate-resistant transgenic rice varieties and hybrid rice (F1) and their succeeding generations (F2-F4) were planted for three years in weedy-rice-free field plots adjacent to experimental weedy-rice fields. Weedy-rice-like (feral) plants, both glufosinate-resistant and with red-pericarp seed, were initially found only among the F3 generations of the two glufosinate-resistant transgenic hybrid rice. The composite fitness (an index based on eight productivity and weediness traits) of the feral progeny was significantly higher than that of glufosinate-resistant transgenic hybrid rice (the original female parent of feral progeny) under common monoculture garden conditions. Hybrid rice progeny segregated into individuals of variable height and extended flowering. Hybrid rice F2 generations had higher outcrossing rates by pollen reception (0.96%-1.65%) than their progenitors (0.07%-0.98%). Herbicide-resistant weedy rice can rapidly arise by pollen-mediated gene flow from weedy to transgenic hybrid rice. Their segregating pollen-receptive progeny pose greater agro-ecological risk than transgenic varieties. The safety assessment and management regulations for transgenic hybrid rice should take into account the risk of bidirectional gene flow.

Birch pollen-related food allergy to legumes: identification and characterization of the Bet v 1 homologue in mungbean (Vigna radiata), Vig r 1.

PubMed

Mittag, D; Vieths, S; Vogel, L; Wagner-Loew, D; Starke, A; Hunziker, P; Becker, W-M; Ballmer-Weber, B K

2005-08-01

Recently allergic reactions to legumes mediated by Bet v 1-homologous food allergens were described for soy and peanut. In this study we assessed allergic reactions to another legume, to mungbean seedlings, and identified its Bet v 1-homologous allergen Vig r 1. Ten patients were selected who had a history of allergic reactions to mungbean seedlings and a respiratory allergy to birch pollen. The Bet v 1 homologue in mungbean seedlings, Vig r 1, was cloned by a PCR strategy, expressed in Escherichia coli, and purified by preparative SDS-PAGE. In all sera, specific IgE against birch pollen, Bet v 1, Bet v 2, Vig r 1, and the Bet v 1 homologues in soy (Gly m 4) and cherry (Pru av 1) was determined by CAP-FEIA. Cross-reactivity of specific IgE with Vig r 1, Bet v 1, Gly m 4, and Pru av 1 was assessed by immunoblot inhibition. Expression of Vig r 1 during development of mungbean seedlings and under wounding stress was analysed by immunoblotting. The Vig r 1 double band was analysed by matrix-assisted laser desorption/ionization time-of-flight and liquid chromatography/tandem mass spectrometry (LC/MS/MS). All patients were sensitized to birch pollen and Bet v 1, 20% to Bet v 2, and 90% to Gly m 4. Seventy percent of the patients showed IgE binding to a double band at 15 kDa in mungbean extract that was inhibited after pre-incubation of sera with rBet v 1. PCR cloning revealed that the mungbean homologue of Bet v 1 had a molecular weight of 16.2 kDa, a calculated pI of 4.6% and 42.8% amino acid sequence identity with Bet v 1. MS analysis confirmed similarity of the double band with the deduced Vig r 1 sequence, but also indicated the existence of other Vig r 1 isoforms. ImmunoCAP analysis detected IgE against Vig r 1 in 80% of the sera. IgE binding to Vig r 1 was inhibited with Gly m 4 in six of six and with rPru av 1 in four of six patients. Vig r 1 expression occurred during development of seedlings and was increased by wounding stress. Food allergy to mungbean seedlings can be caused by primary sensitization to birch pollen and is mediated by Vig r 1 in the majority of the patients with birch pollen-related allergy to mungbean seedlings.

Prevalence of pollen sensitization in younger children who have asthma.

PubMed

Ogershok, Paul R; Warner, Daniel J; Hogan, Mary Beth; Wilson, Nevin W

2007-01-01

It is commonly believed that young children are incapable of pollen sensitization; therefore, skin testing usually is not performed to these allergens. The purpose of this study was to identify the frequency of positive skin tests to outdoor allergens among younger children who have asthma. Patients who have asthma, aged 6 months to 10 years, were evaluated for pollen sensitization over a 10-year period. Skin-prick testing was performed to relevant individual aeroallergens including trees, grasses, and weeds. Testing for perennial indoor allergens such as dust mites, cats, dogs, cockroaches, and molds was performed also. A total of 687 children with asthma were evaluated. No child <12 months old was sensitized to pollens. Children between 12 and 24 months of age had a 29% incidence of pollen sensitization. Three-year-old children were as likely to be skin test positive to pollen as an indoor allergen. Notably, 49% of 3- and 4-year olds were sensitized to outdoor allergens. Primary sensitizing pollens in this age group were short ragweed, box elder, and June grass. In this population, pollen sensitization was not related to tobacco or wood smoke exposure. Although it is widely believed that young children with asthma are most commonly allergic to indoor allergens, almost 40% of our 1- to 3-year old children with asthma showed IgE-mediated sensitivity to outdoor allergens. Pediatric allergists should consider performing skin-prick testing to their local common aeroallergens in young children with asthma and seasonal symptoms.

Prevalence of immunoglobulin E-mediated food allergy in 6-9-year-old urban schoolchildren in the eastern Black Sea region of Turkey.

PubMed

Orhan, F; Karakas, T; Cakir, M; Aksoy, A; Baki, A; Gedik, Y

2009-07-01

The prevalence of adverse reactions to food in childhood in Turkey is not known. We aimed to investigate the prevalence and characteristics of IgE-mediated food allergies (FAs) in 6-9-year-old urban schoolchildren. This cross-sectional study recruited 3500 of the randomly selected 6-9-year-old urban schoolchildren from the eastern Black Sea region of Turkey during 2006. Following a self-administered questionnaire completed by the parents and the child, consenting children were invited for skin prick tests (SPTs) and oral food challenges. Children with suspected IgE-mediated FA were skin prick tested with a predefined panel of food allergens (milk, hen's egg, soy, wheat, peanut, fish, and hazelnut), aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, dog, Alternaria, grass pollen mix, weed pollen mix, and tree pollen mix), and food allergens reported in the questionnaire. All children with a positive SPT to any food were invited for a double-blind, placebo-controlled food challenge (DBPCFC). The prevalence of IgE-mediated FA was established using DBPCFCs. The response rate to the questionnaire was 78.2% (2739/3500). The estimated prevalence of parental-reported IgE-mediated FA was 5.7% (156/2739) [95% confidence interval (CI), 4.83-6.57%]. The rate of sensitization to the food allergens was 33.1% (48/145) in the parental-reported group. The confirmed prevalence of IgE-mediated FA by means of DBPCFC in 6-9-year-old urban schoolchildren living in the eastern Black Sea region of Turkey was 0.80% (22/2739) (95% CI, 0.47-1.13%). The most common allergenic foods were beef (31.8%), cow's milk (18.1%), cocoa (18.1%), hen's egg (13.6%), and kiwi (13.6%). The rate of reported IgE-mediated FA was significantly higher than clinically confirmed FA by means of DBPCFC (odds ratio, 7.46; 95% CI, 4.67-12.01; P<0.0001). The order of allergenic foods was different and somewhat unique to the eastern Black Sea region of Turkey when compared with western countries.

Cotton transformation via pollen tube pathway.

PubMed

Wang, Min; Zhang, Baohong; Wang, Qinglian

2013-01-01

Although many gene transfer methods have been employed for successfully obtaining transgenic cotton, the major constraint in cotton improvement is the limitation of genotype because the majority of transgenic methods require plant regeneration from a single transformed cell which is limited by cotton tissue culture. Comparing with other plant species, it is difficult to induce plant regeneration from cotton; currently, only a limited number of cotton cultivars can be cultured for obtaining regenerated plants. Thus, development of a simple and genotype-independent genetic transformation method is particularly important for cotton community. In this chapter, we present a simple, cost-efficient, and genotype-independent cotton transformation method-pollen tube pathway-mediated transformation. This method uses pollen tube pathway to deliver transgene into cotton embryo sacs and then insert foreign genes into cotton genome. There are three major steps for pollen tube pathway-mediated genetic transformation, which include injection of -foreign genes into pollen tube, integration of foreign genes into plant genome, and selection of transgenic plants.

A two-generation analysis of pollen pool genetic structure in flowering dogwood Cornus florida (Cornaceae), in the Missouri Ozarks

Treesearch

Victoria L. Sork; Peter E. Smouse; Victoria J. Apsit; Rodney J. Dyer; Robert D. Westfall

2005-01-01

Anthropogenic landscape change can disrupt gene flow. As part of the Missouri Ozark Forest Ecosystem Project, this study examined whether silvicultural practices influence pollen-mediated gene movement in the insect-pollinated species, Cornus florida L., by comparing pollen pool structure (ΦST) among clear-cutting,...

Cell-Cell Interactions during pollen tube guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daphne Preuss

The long-term goal of this research is to identify the signaling molecules that mediate plant cell-cell interactions during pollination. The immediate goals of this project are to perform genetic and molecular analysis of pollen tube guidance. Specifically, we proposed to: 1. Characterize the pistil components that direct pollen tube navigation using the Arabidopsis thaliana in vitro pollen tube guidance system 2. Identify pistil signals that direct pollen tube guidance by a) using microarrays to profile gene expression in developing pistils, and b) employing proteomics and metabolomics to isolate pollen tube guidance signals. 3. Explore the genetic basis of natural variationmore » in guidance signals, comparing the in vitro interactions between pollen and pistils from A. thaliana and its close relatives.« less

Wind-mediated horseweed (Conyza canadensis) gene flow: pollen emission, dispersion, and deposition.

PubMed

Huang, Haiyan; Ye, Rongjian; Qi, Meilan; Li, Xiangzhen; Miller, David R; Stewart, Charles Neal; DuBois, David W; Wang, Junming

2015-07-01

Horseweed (Conyza canadensis) is a problem weed in crop production because of its evolved resistance to glyphosate and other herbicides. Although horseweed is mainly self-pollinating, glyphosate-resistant (GR) horseweed can pollinate glyphosate-susceptible (GS) horseweed. To the best of our knowledge, however, there are no available data on horseweed pollen production, dispersion, and deposition relative to gene flow and the evolution of resistance. To help fill this knowledge gap, a 43-day field study was performed in Champaign, Illinois, USA in 2013 to characterize horseweed atmospheric pollen emission, dispersion, and deposition. Pollen concentration and deposition, coupled with atmospheric data, were measured in a source field (180 m by 46 m) and its surrounding areas up to 1 km downwind horizontally and up to 100 m vertically. The source strength (emission rate) ranged from 0 to 140 pollen grains per plant per second (1170 to 2.1×10(6) per plant per day). For the life of the study, the estimated number of pollen grains generated from this source field was 10.5×10(10) (2.3×10(6) per plant). The release of horseweed pollen was not strongly correlated to meteorological data and may be mainly determined by horseweed physiology. Horseweed pollen reached heights of 80 to100 m, making long-distance transport possible. Normalized (by source data) pollen deposition with distance followed a negative-power exponential curve. Normalized pollen deposition was 2.5% even at 480 m downwind from the source edge. Correlation analysis showed that close to or inside the source field at lower heights (≤3 m) vertical transport was related to vertical wind speed, while horizontal pollen transport was related to horizontal wind speed. High relative humidity prevented pollen transport at greater heights (3-100 m) and longer distances (0-1000 m) from the source. This study can contribute to the understanding of how herbicide-resistance weeds or invasive plants affect ecology through wind-mediated pollination and invasion.

Occupational allergy to flowers: immunoblot analysis of allergens in freesia, gerbera and chrysanthemum pollen.

PubMed

van Toorenenbergen, A W

2014-10-01

High exposure to pollen from ornamental flowers can induce an IgE-mediated occupational allergy in florists and horticulture workers. We investigated IgE-binding antigens in chrysanthemum, freesia and gerbera pollen by immunoblot analysis and analysed the cross-reactivity of these pollen with birch, grass and mugwort pollen. In immunoblots with chrysanthemum pollen, major IgE-binding structures were seen with a molecular weight (MW) of approximately 25, 45 and 65 kD. In the immunoblots with freesia pollen, IgE from freesia pollen was directed against two proteins with an MW of approximately 15 kD. Most sera showed IgE binding to an approximately 15 kD band in gerbera pollen; with some sera additional bands were seen in the range of 30-50 kD. IgE binding to chrysanthemum pollen was inhibited by mugwort pollen only, whereas IgE binding to freesia pollen was suppressed by birch, grass and mugwort pollen. The inhibitory activity of birch and grass pollen extract on IgE binding to gerbera pollen extract was serum dependent and ranged from no inhibition to complete inhibition. Occupational exposure to many different flowers induced IgE against all three types of pollen. Exposure in greenhouses to gerbera flowers elicited mainly IgE against gerbera pollen. Mugwort pollen extract inhibited IgE binding to pollen from all three flowers. © 2014 John Wiley & Sons Ltd.

Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana

PubMed Central

Bienert, Gerd Patrick; Barberini, María Laura

2016-01-01

In flowers with dry stigmas, pollen development, pollination, and pollen tube growth require spatial and temporal regulation of water and nutrient transport. To better understand the molecular mechanisms involved in reproductive processes, we characterized NIP4;1 and NIP4;2, two pollen-specific aquaporins of Arabidopsis thaliana. NIP4;1 and NIP4;2 are paralogs found exclusively in the angiosperm lineage. Although they have 84% amino acid identity, they displayed different expression patterns. NIP4;1 has low expression levels in mature pollen, while NIP4;2 expression peaks during pollen tube growth. Additionally, NIP4;1pro:GUS flowers showed GUS activity in mature pollen and pollen tubes, whereas NIP4;2pro:GUS flowers only in pollen tubes. Single T-DNA mutants and double artificial microRNA knockdowns had fewer seeds per silique and reduced pollen germination and pollen tube length. Transport assays in oocytes showed NIP4;1 and NIP4;2 function as water and nonionic channels. We also found that NIP4;1 and NIP4;2 C termini are phosphorylated by a pollen-specific CPK that modifies their water permeability. Survival assays in yeast indicated that NIP4;1 also transports ammonia, urea, boric acid, and H2O2. Thus, we propose that aquaporins NIP4;1 and NIP4;2 are exclusive components of the reproductive apparatus of angiosperms with partially redundant roles in pollen development and pollination. PMID:27095837

Adaptor protein complex 2-mediated endocytosis is crucial for male reproductive organ development in Arabidopsis.

PubMed

Kim, Soo Youn; Xu, Zheng-Yi; Song, Kyungyoung; Kim, Dae Heon; Kang, Hyangju; Reichardt, Ilka; Sohn, Eun Ju; Friml, Jirí; Juergens, Gerd; Hwang, Inhwan

2013-08-01

Fertilization in flowering plants requires the temporal and spatial coordination of many developmental processes, including pollen production, anther dehiscence, ovule production, and pollen tube elongation. However, it remains elusive as to how this coordination occurs during reproduction. Here, we present evidence that endocytosis, involving heterotetrameric adaptor protein complex 2 (AP-2), plays a crucial role in fertilization. An Arabidopsis thaliana mutant ap2m displays multiple defects in pollen production and viability, as well as elongation of staminal filaments and pollen tubes, all of which are pivotal processes needed for fertilization. Of these abnormalities, the defects in elongation of staminal filaments and pollen tubes were partially rescued by exogenous auxin. Moreover, DR5rev:GFP (for green fluorescent protein) expression was greatly reduced in filaments and anthers in ap2m mutant plants. At the cellular level, ap2m mutants displayed defects in both endocytosis of N-(3-triethylammonium-propyl)-4-(4-diethylaminophenylhexatrienyl) pyridinium dibromide, a lypophilic dye used as an endocytosis marker, and polar localization of auxin-efflux carrier PIN FORMED2 (PIN2) in the stamen filaments. Moreover, these defects were phenocopied by treatment with Tyrphostin A23, an inhibitor of endocytosis. Based on these results, we propose that AP-2-dependent endocytosis plays a crucial role in coordinating the multiple developmental aspects of male reproductive organs by modulating cellular auxin level through the regulation of the amount and polarity of PINs.

Adaptor Protein Complex 2–Mediated Endocytosis Is Crucial for Male Reproductive Organ Development in Arabidopsis[W

PubMed Central

Kim, Soo Youn; Xu, Zheng-Yi; Song, Kyungyoung; Kim, Dae Heon; Kang, Hyangju; Reichardt, Ilka; Sohn, Eun Ju; Friml, Jiří; Juergens, Gerd; Hwang, Inhwan

2013-01-01

Fertilization in flowering plants requires the temporal and spatial coordination of many developmental processes, including pollen production, anther dehiscence, ovule production, and pollen tube elongation. However, it remains elusive as to how this coordination occurs during reproduction. Here, we present evidence that endocytosis, involving heterotetrameric adaptor protein complex 2 (AP-2), plays a crucial role in fertilization. An Arabidopsis thaliana mutant ap2m displays multiple defects in pollen production and viability, as well as elongation of staminal filaments and pollen tubes, all of which are pivotal processes needed for fertilization. Of these abnormalities, the defects in elongation of staminal filaments and pollen tubes were partially rescued by exogenous auxin. Moreover, DR5rev:GFP (for green fluorescent protein) expression was greatly reduced in filaments and anthers in ap2m mutant plants. At the cellular level, ap2m mutants displayed defects in both endocytosis of N-(3-triethylammonium-propyl)-4-(4-diethylaminophenylhexatrienyl) pyridinium dibromide, a lypophilic dye used as an endocytosis marker, and polar localization of auxin-efflux carrier PIN FORMED2 (PIN2) in the stamen filaments. Moreover, these defects were phenocopied by treatment with Tyrphostin A23, an inhibitor of endocytosis. Based on these results, we propose that AP-2–dependent endocytosis plays a crucial role in coordinating the multiple developmental aspects of male reproductive organs by modulating cellular auxin level through the regulation of the amount and polarity of PINs. PMID:23975898

Molecular cloning of plane pollen allergen Pla a 3 and its utility as diagnostic marker for peach associated plane pollen allergy.

PubMed

Wangorsch, A; Larsson, H; Messmer, M; García-Moral, A; Lauer, I; Wolfheimer, S; Schülke, S; Bartra, J; Vieths, S; Lidholm, J; Scheurer, S

2016-05-01

Non-specific lipid transfer proteins (nsLTP) are considered to provoke allergic symptoms to plane tree pollen, which are frequently associated with peach allergy. The objective was to clone the cDNA of plane pollen nsLTP Pla a 3, to characterize IgE-binding and allergenic potency of recombinant Pla a 3 in comparison to its natural counterpart and peach nsLTP Pru p 3. Natural Pla a 3 was purified from plane pollen and analysed by mass spectrometry (MS). Recombinant Pla a 3 was characterized by SDS-PAGE and CD spectroscopy. Specific IgE to extract, components of plane pollen and Pru p 3 was measured by ImmunoCAP in sera of patients allergic to either plane pollen (n = 10), peach (n = 15) or both (n = 15). Biological potency of the proteins was investigated by in vitro mediator release assays and IgE cross-reactivity by competitive ELISA. Two Pla a 3 isoforms were identified. Recombinant Pla a 3 showed high purity, structural integrity, IgE-binding capacity comparable to nPla a 3 and biological potency. Sensitization to plane pollen extract was confirmed in 24/25 plane pollen allergics. The frequency of sensitization to Pla a 3 was 53% among patients allergic to both plane pollen and peach and 10% among plane pollen allergics tolerating peach where most patients were sensitized to Pla a 1. Pla a 3 and Pru p 3 showed strong bi-directional IgE cross-reactivity in patients allergic to peach and plane pollen, but not in peach allergics tolerating plane pollen. Levels of IgE-binding were generally higher to Pru p 3 than to Pla a 3. Sensitization to Pla a 3 is relevant in a subgroup of plane pollen allergics with concomitant peach allergy. IgE testing with Pla a 3 may serve as a marker to identify plane pollen allergic patients at risk of LTP-mediated food reactions and thereby improve in vitro diagnostic procedures. © 2016 John Wiley & Sons Ltd.

A two-generation analysis of pollen pool genetic structure in flowering dogwood, Cornus florida (Cornaceae), in the Missouri Ozarks.

PubMed

Sork, Victoria L; Smouse, Peter E; Apsit, Victoria J; Dyer, Rodney J; Westfall, Robert D

2005-02-01

Anthropogenic landscape change can disrupt gene flow. As part of the Missouri Ozark Forest Ecosystem Project, this study examined whether silvicultural practices influence pollen-mediated gene movement in the insect-pollinated species, Cornus florida L., by comparing pollen pool structure (Φ(st)) among clear-cutting, selective cutting, and uncut regimes with the expectation that pollen movement should be least in the uncut regime. Using a sample of 1500 seedlings-10 each from 150 seed parents (43 in clear-cut, 74 in selective, and 33 in control sites) from six sites (each ranging from 266 to 527 ha), eight allozyme loci were analyzed with a pollen pool structure approach known as TwoGener (Smouse et al., 2001; Evolution 55: 260-271). This analysis revealed that pollen pool structure was less in clear-cut (Φ(C) = 0.090, P < 0.001) than in uncut areas (Φ(U) = 0.174, P < 0.001), with selective-cut intermediate (Φ(S) = 0.125, P < 0.001). These estimates translate into more effective pollen donors (N(ep)) in clear-cut (N(ep) = 5.56) and selective-cut (N(ep) = 4.00) areas than in uncut areas (N(ep) = 2.87). We demonstrate that Φ(C) ≤ Φ(S) ≤ Φ(U), with Φ(C) significantly smaller than Φ(U) (P < 0.034). The findings imply that, as long as a sufficiently large number of seed parents remain to provide adequate reproduction and to avoid a genetic bottleneck in the effective number of mothers, silvicultural management may not negatively affect the effective number of pollen parents, and hence subsequent genetic diversity in Cornus florida.

Calcium-Dependent Protein Kinase Isoforms in Petunia Have Distinct Functions in Pollen Tube Growth, Including Regulating Polarity[W

PubMed Central

Yoon, Gyeong Mee; Dowd, Peter E.; Gilroy, Simon; McCubbin, Andrew G.

2006-01-01

Calcium is a key regulator of pollen tube growth, but little is known concerning the downstream components of the signaling pathways involved. We identified two pollen-expressed calmodulin-like domain protein kinases from Petunia inflata, CALMODULIN-LIKE DOMAIN PROTEIN KINASE1 (Pi CDPK1) and Pi CDPK2. Transient overexpression or expression of catalytically modified Pi CDPK1 disrupted pollen tube growth polarity, whereas expression of Pi CDPK2 constructs inhibited tube growth but not polarity. Pi CDPK1 exhibited plasma membrane localization most likely mediated by acylation, and we present evidence that suggests this localization is critical to the biological function of this kinase. Pi CDPK2 substantially localized to as yet unidentified internal membrane compartments, and this localization was again, at least partially, mediated by acylation. In contrast with Pi CDPK1, altering the localization of Pi CDPK2 did not noticeably alter the effect of overexpressing this isoform on pollen tube growth. Ca2+ requirements for Pi CDPK1 activation correlated closely with Ca2+ concentrations measured in the growth zone at the pollen tube apex. Interestingly, loss of polarity associated with overexpression of Pi CDPK1 was associated with elevated cytosolic Ca2+ throughout the bulging tube tip, suggesting that Pi CDPK1 may participate in maintaining Ca2+ homeostasis. These results are discussed in relation to previous models for Ca2+ regulation of pollen tube growth. PMID:16531501

Molecular and functional characterization of CYP6BQ23, a cytochrome P450 conferring resistance to pyrethroids in European populations of pollen beetle, Meligethes aeneus.

PubMed

Zimmer, Christoph T; Bass, Chris; Williamson, Martin S; Kaussmann, Martin; Wölfel, Katharina; Gutbrod, Oliver; Nauen, Ralf

2014-02-01

The pollen beetle (Meligethes aeneus F.) is widespread throughout much of Europe where it is a major coleopteran pest of oilseed rape (Brassica napus). The reliance on synthetic insecticides for control, particularly the pyrethroid class, has led to the development of populations with high levels of resistance. Resistance to pyrethroids is now widespread throughout Europe and is thought to be mediated by enhanced detoxification by cytochrome P450ś and/or mutation of the pyrethroid target-site, the voltage-gated sodium channel. However, in the case of cytochrome P450 mediated detoxification, the specific enzyme(s) involved has (have) not yet been identified. In this study a degenerate PCR approach was used to identify ten partial P450 gene sequences from pollen beetle. Quantitative PCR was then used to examine the level of expression of these genes in a range of pollen beetle populations that showed differing levels of resistance to pyrethroids in bioassays. The study revealed a single P450 gene, CYP6BQ23, which is significantly and highly overexpressed (up to ∼900-fold) in adults and larvae of pyrethroid resistant strains compared to susceptible strains. CYP6BQ23 overexpression is significantly correlated with both the level of resistance and with the rate of deltamethrin metabolism in microsomal preparations of these populations. Functional recombinant expression of full length CYP6BQ23 along with cytochrome P450 reductase in an insect (Sf9) cell line showed that it is able to efficiently metabolise deltamethrin to 4-hydroxy deltamethrin. Furthermore we demonstrated by detection of 4-hydroxy tau-fluvalinate using ESI-TOF MS/MS that functionally expressed CYP6BQ23 also metabolizes tau-fluvalinate. A protein model was generated and subsequent docking simulations revealed the predicted substrate-binding mode of both deltamethrin and tau-fluvalinate to CYP6BQ23. Taken together these results strongly suggest that the overexpression of CYP6BQ23 is the primary mechanism conferring pyrethroid resistance in pollen beetle populations throughout much of Europe. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pollinator-mediated competition between two congeners, Limnanthes douglasii subsp. rosea and L. alba (Limnanthaceae).

PubMed

Briscoe Runquist, Ryan D

2012-07-01

Pollinator visits are essential for reproduction in many plants, yet interspecific movements of pollinators can also lead to competitive interactions between coflowering species. Pollination-mediated reductions in fertility could potentially lead to exclusion of competing plant species, and may generate spatial variation in the associations among coflowering species across a landscape. I documented the potential for heterospecific pollen transfer to cause competitive interactions between two annual grassland species native to California, Limnanthes douglasii subsp. rosea and L. alba, two reproductively incompatible species that have broadly overlapping geographic ranges in the foothills of the Sierra Nevada. I observed pollinator movement in constructed arrays and controlled crosses in the greenhouse and field to investigate the consequences of heterospecific pollen transfer. Pollinators move readily between species when they are presented together in experimental arrays. In the greenhouse, deposition of heterospecific pollen decreased fertility in both species. The decrease in seeds produced per flower was much more pronounced in L. d. rosea (90.6% reduction) than in L. alba (40.8% reduction). In field experiments, L. d. rosea plants that received pollen from heterospecific neighbors first showed >50% reduction in per-flower fertility. Under natural pollination conditions, heterospecific pollen transfer has the ability to decrease the fertility of L. d. rosea when it occurs at low frequency in mixed stands. Accordingly, pollinator-mediated competition may contribute to the locally disjunct distributions of these two species. It may also influence important restoration decisions in vernal pool habitats.

Comparative proteomic analysis reveals a dynamic pollen plasma membrane protein map and the membrane landscape of receptor-like kinases and transporters important for pollen tube growth and interaction with pistils in rice.

PubMed

Yang, Ning; Wang, Tai

2017-01-05

The coordination of pollen tube (PT) growth, guidance and timely growth arrest and rupture mediated by PT-pistil interaction is crucial for the PT to transport sperm cells into ovules for double fertilization. The plasma membrane (PM) represents an important interface for cell-cell interaction, and PM proteins of PTs are pioneers for mediating PT integrity and interaction with pistils. Thus, understanding the mechanisms underlying these events is important for proteomics. Using the efficient aqueous polymer two-phase system and alkali buffer treatment, we prepared high-purity PM from mature and germinated pollen of rice. We used iTRAQ quantitative proteomic methods and identified 1,121 PM-related proteins (PMrPs) (matched to 899 loci); 192 showed differential expression in the two pollen cell types, 119 increased and 73 decreased in abundance during germination. The PMrP and differentially expressed PMrP sets all showed a functional skew toward signal transduction, transporters, wall remodeling/metabolism and membrane trafficking. Their genomic loci had strong chromosome bias. We found 37 receptor-like kinases (RLKs) from 8 kinase subfamilies and 209 transporters involved in flux of diversified ions and metabolites. In combination with the rice pollen transcriptome data, we revealed that in general, the protein expression of these PMrPs disagreed with their mRNA expression, with inconsistent mRNA expression for 74% of differentially expressed PMrPs. This study identified genome-wide pollen PMrPs, and provided insights into the membrane profile of receptor-like kinases and transporters important for pollen tube growth and interaction with pistils. These pollen PMrPs and their mRNAs showed discordant expression. This work provides resource and knowledge to further dissect mechanisms by which pollen or the PT controls PMrP abundance and monitors interactions and ion and metabolite exchanges with female cells in rice.

Migratory beekeeping practices contribute insignificantly to transgenic pollen flow among fields of alfalfa produced for seed

USDA-ARS?s Scientific Manuscript database

Increased use of genetically engineered crops in agriculture has raised concerns over pollinator-mediated gene flow between transgenic and conventional agricultural varieties. This study evaluated whether contracted migratory beekeeping practices influence transgenic pollen flow among spatially iso...

POLLEN FLOW IN THE ENVIRONMENT - DEVELOPMENT OF A RESEARCH PROGRAM

EPA Science Inventory

The USEPA Office of Research and Development seeks to provide to the agency and society the best information relating to the status of the environment and any related technology maintaining environmental quality. In this effort, a recent research workshop (Pollen Mediated Gene Fl...

Pollen from accurately dated speleothems supports alpine glacier low-stands during the early Holocene

NASA Astrophysics Data System (ADS)

Festi, Daniela; Hoffmann, Dirk L.; Luetscher, Marc

2016-07-01

Deciphering pollen assemblages from alpine speleothems holds potential to provide unique information about past vegetation in rapidly changing environments. Here, we reconstruct subsurface aerosol transport at Milchbach cave (Switzerland, 1840 m asl) based on the pollen content of two Holocene stalagmites. We demonstrate that pollen is chiefly associated with bacterially mediated calcite fabrics, typical of a well-ventilated cave system. In contrast, pollen is absent from columnar calcite fabrics confirming that hydrological transport is not a significant process for the incorporation of pollen into speleothems at Milchbach cave. Our results support significant changes in the subsurface ventilation regime, which can be associated with the waxing and waning of Upper Grindelwald glacier. Pollen assemblages obtained from six carbonate sub-samples attest the presence of a mixed deciduous forest in the Grindelwald valley during the early and middle Holocene, in agreement with coeval regional pollen records. This study demonstrates that even small amounts of calcite (0.3-2.8 cm3) are capable of delivering pollen spectra representative of the original vegetation if sufficiently elevated deposition fluxes are provided.

Aridopsis COBRA-LIKE 10, a GPI-anchored protien, mediates directional growth of pollen tubes

USDA-ARS?s Scientific Manuscript database

Successful reproduction of flowering plants requires constant communication between female tissues and growing pollen tubes. Female cells secrete molecules and peptides as nutrients or guidance cues for fast and directional tube growth, which is executed by dynamic changes of intracellular activitie...

Apomixis and ploidy barrier suppress pollen-mediated gene flow in field grown transgenic turf and forage grass (Paspalum notatum Flüggé).

PubMed

Sandhu, Sukhpreet; Blount, Ann R; Quesenberry, Kenneth H; Altpeter, Fredy

2010-09-01

Bahiagrass (Paspalum notatum Flüggé) is the predominant forage grass in the southeastern US. The commercially important bahiagrass cultivar 'Argentine' is preferred for genetic transformation over sexual diploid cytotypes, since it produces uniform seed progeny through apomixis. Pseudogamous apomictic seed production in Argentine bahiagrass may contribute to transgene confinement. It is characterized by embryo development which is independent of fertilization of the egg cell, but requires fertilization with compatible pollen to produce the endosperm. Pollen-mediated gene transfer from transgenic, glufosinate-resistant apomictic bahiagrass as pollen donor at close proximity (0.5-3.5 m) with non-transgenic sexual or apomictic bahiagrass cultivars as pollen receptors was evaluated under field conditions. Hybridization frequency was evaluated by glufosinate herbicide resistance in >23,300 seedlings derived from open-pollinated (OP) pollen receptor plants. Average gene transfer between transgenic apomictic, tetraploid and sexual diploid bahiagrass was 0.03%. Herbicide-resistant hybrids confirmed by immuno-chromatographic detection of the PAT protein displayed a single copy bar gene identical to the pollen parent. Hybrids resulting from diploid pollen receptors were confirmed as triploids or aneu-triploids with significantly reduced vigor and seed set as compared to the parents. Transmission of transgenes to sexual bahiagrass is severely restricted by the ploidy difference between tetraploid apomicts and diploid sexual bahiagrass. Average gene transfer between transgenic apomictic tetraploid and non-transgenic, apomictic tetraploid bahiagrass was 0.17%, confirming a very low frequency of amphimixis in apomictic bahiagrass cultivars. While not providing complete transgene containment, gene transfer between transgenic apomictic and non-transgenic bahiagrass occurs at a much lower frequency than reported for other cross-pollinating or facultative apomictic grasses.

Pollen-mediated gene flow and seed exchange in small-scale Zambian maize farming, implications for biosafety assessment

NASA Astrophysics Data System (ADS)

Bøhn, Thomas; Aheto, Denis W.; Mwangala, Felix S.; Fischer, Klara; Bones, Inger Louise; Simoloka, Christopher; Mbeule, Ireen; Schmidt, Gunther; Breckling, Broder

2016-10-01

Gene flow in agricultural crops is important for risk assessment of genetically modified (GM) crops, particularly in countries with a large informal agricultural sector of subsistence cultivation. We present a pollen flow model for maize (Zea mays), a major staple crop in Africa. We use spatial properties of fields (size, position) in three small-scale maize farming communities in Zambia and estimate rates of cross-fertilisation between fields sown with different maize varieties (e.g. conventional and transgene). As an additional factor contributing to gene flow, we present data on seed saving and sharing among farmers that live in the same communities. Our results show that: i) maize fields were small and located in immediate vicinity of neighboring fields; ii) a majority of farmers saved and shared seed; iii) modeled rates of pollen-mediated gene flow showed extensive mixing of germplasm between fields and farms and iv) as a result, segregation of GM and non-GM varieties is not likely to be an option in these systems. We conclude that the overall genetic composition of maize, in this and similar agricultural contexts, will be strongly influenced both by self-organised ecological factors (pollen flow), and by socially mediated intervention (seed recycling and sharing).

Pollen-mediated gene flow and seed exchange in small-scale Zambian maize farming, implications for biosafety assessment

PubMed Central

Bøhn, Thomas; Aheto, Denis W.; Mwangala, Felix S.; Fischer, Klara; Bones, Inger Louise; Simoloka, Christopher; Mbeule, Ireen; Schmidt, Gunther; Breckling, Broder

2016-01-01

Gene flow in agricultural crops is important for risk assessment of genetically modified (GM) crops, particularly in countries with a large informal agricultural sector of subsistence cultivation. We present a pollen flow model for maize (Zea mays), a major staple crop in Africa. We use spatial properties of fields (size, position) in three small-scale maize farming communities in Zambia and estimate rates of cross-fertilisation between fields sown with different maize varieties (e.g. conventional and transgene). As an additional factor contributing to gene flow, we present data on seed saving and sharing among farmers that live in the same communities. Our results show that: i) maize fields were small and located in immediate vicinity of neighboring fields; ii) a majority of farmers saved and shared seed; iii) modeled rates of pollen-mediated gene flow showed extensive mixing of germplasm between fields and farms and iv) as a result, segregation of GM and non-GM varieties is not likely to be an option in these systems. We conclude that the overall genetic composition of maize, in this and similar agricultural contexts, will be strongly influenced both by self-organised ecological factors (pollen flow), and by socially mediated intervention (seed recycling and sharing). PMID:27694819

Pollen-mediated gene flow and seed exchange in small-scale Zambian maize farming, implications for biosafety assessment.

PubMed

Bøhn, Thomas; Aheto, Denis W; Mwangala, Felix S; Fischer, Klara; Bones, Inger Louise; Simoloka, Christopher; Mbeule, Ireen; Schmidt, Gunther; Breckling, Broder

2016-10-03

Gene flow in agricultural crops is important for risk assessment of genetically modified (GM) crops, particularly in countries with a large informal agricultural sector of subsistence cultivation. We present a pollen flow model for maize (Zea mays), a major staple crop in Africa. We use spatial properties of fields (size, position) in three small-scale maize farming communities in Zambia and estimate rates of cross-fertilisation between fields sown with different maize varieties (e.g. conventional and transgene). As an additional factor contributing to gene flow, we present data on seed saving and sharing among farmers that live in the same communities. Our results show that: i) maize fields were small and located in immediate vicinity of neighboring fields; ii) a majority of farmers saved and shared seed; iii) modeled rates of pollen-mediated gene flow showed extensive mixing of germplasm between fields and farms and iv) as a result, segregation of GM and non-GM varieties is not likely to be an option in these systems. We conclude that the overall genetic composition of maize, in this and similar agricultural contexts, will be strongly influenced both by self-organised ecological factors (pollen flow), and by socially mediated intervention (seed recycling and sharing).

Bias to pollen odors is affected by early exposure and foraging experience.

PubMed

Arenas, A; Farina, W M

2014-07-01

In many pollinating insects, foraging preferences are adjusted on the basis of floral cues learned at the foraging site. In addition, olfactory experiences gained at early adult stages might also help them to initially choose food sources. To understand pollen search behavior of honeybees, we studied how responses elicited by pollen-based odors are biased in foraging-age workers according to (i) their genetic predisposition to collect pollen, (ii) pollen related information gained during foraging and (iii) different experiences with pollen gained at early adult ages. Bees returning to the hive carrying pollen loads, were strongly biased to unfamiliar pollen bouquets when tested in a food choice device against pure odors. Moreover, pollen foragers' orientation response was specific to the odors emitted by the pollen type they were carrying on their baskets, which suggests that foragers retrieve pollen odor information to recognize rewarding flowers outside the hive. We observed that attraction to pollen odor was mediated by the exposure to a pollen diet during the first week of life. We did not observe the same attraction in foraging-age bees early exposed to an artificial diet that did not contain pollen. Contrary to the specific response observed to cues acquired during foraging, early exposure to single-pollen diets did not bias orientation response towards a specific pollen odor in foraging-age bees (i.e. bees chose equally between the exposed and the novel monofloral pollen odors). Our results show that pollen exposure at early ages together with olfactory experiences gained in a foraging context are both relevant to bias honeybees' pollen search behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

Early genetic consequences of defaunation in a large-seeded vertebrate-dispersed palm (Syagrus romanzoffiana)

PubMed Central

Giombini, M I; Bravo, S P; Sica, Y V; Tosto, D S

2017-01-01

Plant populations are seriously threatened by anthropogenic habitat disturbance. In particular, defaunation may disrupt plant-disperser mutualisms, thus reducing levels of seed-mediated gene flow and genetic variation in animal-dispersed plants. This may ultimately limit their adaptive potential and ability to cope with environmental change. Tropical forest remnants are typically deprived of medium to large vertebrates upon which many large-seeded plants rely for accomplishing effective seed dispersal. Our main goal was to examine the potential early genetic consequences of the loss of large vertebrates for large-seeded vertebrate-dispersed plants. We compared the genetic variation in early-stage individuals of the large-seeded palm Syagrus romanzoffiana between continuous protected forest and nearby partially defaunated fragments in the Atlantic Forest of South America. Using nine microsatellites, we found lower allelic richness and stronger fine-scale spatial genetic structure in the disturbed area. In addition, the percentage of dispersed recruits around conspecific adults was lower, although not significantly, in the disturbed area (median values: 0.0 vs 14.4%). On the other hand, no evidence of increased inbreeding or reduced pollen-mediated gene flow (selfing rate and diversity of pollen donors) was found in the disturbed area. Our findings are strongly suggestive of some early genetic consequences resulting from the limitation in contemporary gene flow via seeds, but not pollen, in defaunated areas. Plant-disperser mutualisms involving medium–large frugivores, which are seriously threatened in tropical systems, should therefore be protected to warrant the maintenance of seed-mediated gene flow and genetic diversity in large-seeded plants. PMID:28121308

Hive-stored pollen of honey bees: many lines of evidence are consistent with pollen preservation, not nutrient conversion

PubMed Central

Anderson, Kirk E; Carroll, Mark J; Sheehan, Tim; Mott, Brendon M; Maes, Patrick; Corby-Harris, Vanessa

2014-01-01

Honey bee hives are filled with stored pollen, honey, plant resins and wax, all antimicrobial to differing degrees. Stored pollen is the nutritionally rich currency used for colony growth and consists of 40–50% simple sugars. Many studies speculate that prior to consumption by bees, stored pollen undergoes long-term nutrient conversion, becoming more nutritious ‘bee bread’ as microbes predigest the pollen. We quantified both structural and functional aspects associated with this hypothesis using behavioural assays, bacterial plate counts, microscopy and 454 amplicon sequencing of the 16S rRNA gene from both newly collected and hive-stored pollen. We found that bees preferentially consume fresh pollen stored for <3 days. Newly collected pollen contained few bacteria, values which decreased significantly as pollen were stored >96 h. The estimated microbe to pollen grain surface area ratio was 1:1 000 000 indicating a negligible effect of microbial metabolism on hive-stored pollen. Consistent with these findings, hive-stored pollen grains did not appear compromised according to microscopy. Based on year round 454 amplicon sequencing, bacterial communities of newly collected and hive-stored pollen did not differ, indicating the lack of an emergent microbial community co-evolved to digest stored pollen. In accord with previous culturing and 16S cloning, acid resistant and osmotolerant bacteria like Lactobacillus kunkeei were found in greatest abundance in stored pollen, consistent with the harsh character of this microenvironment. We conclude that stored pollen is not evolved for microbially mediated nutrient conversion, but is a preservative environment due primarily to added honey, nectar, bee secretions and properties of pollen itself. PMID:25319366

Hive-stored pollen of honey bees: many lines of evidence are consistent with pollen preservation, not nutrient conversion.

PubMed

Anderson, Kirk E; Carroll, Mark J; Sheehan, Tim; Lanan, Michele C; Mott, Brendon M; Maes, Patrick; Corby-Harris, Vanessa

2014-12-01

Honey bee hives are filled with stored pollen, honey, plant resins and wax, all antimicrobial to differing degrees. Stored pollen is the nutritionally rich currency used for colony growth and consists of 40-50% simple sugars. Many studies speculate that prior to consumption by bees, stored pollen undergoes long-term nutrient conversion, becoming more nutritious 'bee bread' as microbes predigest the pollen. We quantified both structural and functional aspects associated with this hypothesis using behavioural assays, bacterial plate counts, microscopy and 454 amplicon sequencing of the 16S rRNA gene from both newly collected and hive-stored pollen. We found that bees preferentially consume fresh pollen stored for <3 days. Newly collected pollen contained few bacteria, values which decreased significantly as pollen were stored >96 h. The estimated microbe to pollen grain surface area ratio was 1:1 000 000 indicating a negligible effect of microbial metabolism on hive-stored pollen. Consistent with these findings, hive-stored pollen grains did not appear compromised according to microscopy. Based on year round 454 amplicon sequencing, bacterial communities of newly collected and hive-stored pollen did not differ, indicating the lack of an emergent microbial community co-evolved to digest stored pollen. In accord with previous culturing and 16S cloning, acid resistant and osmotolerant bacteria like Lactobacillus kunkeei were found in greatest abundance in stored pollen, consistent with the harsh character of this microenvironment. We conclude that stored pollen is not evolved for microbially mediated nutrient conversion, but is a preservative environment due primarily to added honey, nectar, bee secretions and properties of pollen itself. © 2014 John Wiley & Sons Ltd.

Distinct effects of pollinator dependence and self-incompatibility on pollen limitation in South African biodiversity hotspots.

PubMed

Rodger, James G; Ellis, Allan G

2016-06-01

Global synthesis indicates that limitation of plant fecundity by pollen receipt (pollen limitation) is positively related to regional plant diversity and is higher for self-incompatible than self-compatible species. While self-incompatible species are always dependent on pollinating agents, self-compatible species may be pollinator-dependent or autofertile. This should cause variation in pollen limitation among self-compatible species, with lower pollen limitation in autofertile species because they do not depend on pollinators. We hypothesized that the intensity of pollen limitation in self-incompatible compared with pollinator-dependent self-compatible species should depend on whether pollen limitation is determined more by quantity than quality of pollen received. We compared pollen limitation between these three groups using a dataset of 70 biotically pollinated species from biodiverse regions of South Africa. Comparison with a global dataset indicated that pollen limitation in the South African biodiversity hotspots was generally comparable to other regions, despite expectations of higher pollen limitation based on the global plant diversity-pollen limitation relationship. Pollen limitation was lowest for autofertile species, as expected. It was also higher for pollinator-dependent self-compatible species than self-incompatible species, consistent with increased pollen-quality limitation in the former group due to negative consequences of pollinator-mediated self-pollination. However, there was a higher frequency of plants with zygomorphic flowers, which were also more pollen-limited, among pollinator-dependent self-compatible species. Thus, we could not attribute this difference in pollen limitation exclusively to a difference in pollen quality. Nevertheless, our results indicate that comparative studies should control for both pollinator dependence and self-incompatiblity when evaluating effects of other factors on pollen limitation. © 2016 The Author(s).

Self-Incompatibility in Papaver rhoeas Activates Nonspecific Cation Conductance Permeable to Ca2+ and K+[W

PubMed Central

Wu, Juyou; Wang, Su; Gu, Yuchun; Zhang, Shaoling; Publicover, Stephen J.; Franklin-Tong, Vernonica E.

2011-01-01

Cellular responses rely on signaling. In plant cells, cytosolic free calcium is a major second messenger, and ion channels play a key role in mediating physiological responses. Self-incompatibility (SI) is an important genetically controlled mechanism to prevent self-fertilization. It uses interaction of matching S-determinants from the pistil and pollen to allow “self” recognition, which triggers rejection of incompatible pollen. In Papaver rhoeas, the S-determinants are PrsS and PrpS. PrsS is a small novel cysteine-rich protein; PrpS is a small novel transmembrane protein. Interaction of PrsS with incompatible pollen stimulates S-specific increases in cytosolic free calcium and alterations in the actin cytoskeleton, resulting in programmed cell death in incompatible but not compatible pollen. Here, we have used whole-cell patch clamping of pollen protoplasts to show that PrsS stimulates SI-specific activation of pollen grain plasma membrane conductance in incompatible but not compatible pollen grain protoplasts. The SI-activated conductance does not require voltage activation, but it is voltage sensitive. It is permeable to divalent cations (Ba2+ ≥ Ca2+ > Mg2+) and the monovalent ions K+ and NH4+ and is enhanced at voltages negative to −100 mV. The Ca2+ conductance is blocked by La3+ but not by verapamil; the K+ currents are tetraethylammonium chloride insensitive and do not require Ca2+. We propose that the SI-stimulated conductance may represent a nonspecific cation channel or possibly two conductances, permeable to monovalent and divalent cations. Our data provide insights into signal-response coupling involving a biologically important response. PrsS provides a rare example of a protein triggering alterations in ion channel activity. PMID:21177472

Determinants of stingless bee nest density in lowland dipterocarp forests of Sabah, Malaysia.

PubMed

Eltz, Thomas; Brühl, Carsten A; van der Kaars, Sander; Linsenmair, Eduard K

2002-03-01

We measured the nest density of stingless bees (Apidae, Meliponini) in undisturbed and logged-over dipterocarp forests in Sabah, northern Borneo, and evaluated hypotheses on proximate factors leading to the observed variation: population control mediated by (1) nest predation, (2) limitation of nest trees, or (3) food limitation. Per-area nest density varied twentyfold across 14 forest sites and was significantly affected by locality, but not by the degree and history of disturbance. Nest density was generally high in sites located in the Sepilok Forest fragment (mean 8.4 nests/ha), bordering mangroves or plantations. In contrast, nest densities in continuous forests were all low (between 0 and 2.1 nests/ha, mean 0.5 nests/ha). Yearly nest mortality was low (13.5-15.0%) over 4 years of observation and did not vary between forest localities, thus limiting the potential of nest predation (1) in creating the observed variation in nest density. The presence of potential nest trees (2), though positively correlated with nest density, explained only a minute fraction of the observed variation. Nest density was best explained by differences in the pollen resources (3) available to the bees (quantified by analysis of pollen in bee garbage). Across five selected sites the amount of nonforest pollen (from mangrove or crop plants) included in diets of Trigona collina was positively correlated with T. collina nest density. External pollen sources are a likely supplement to bee diets at times when little flowering occurs inside the forest, thus increasing overall bee carrying capacity. Pollen limitation was also indicated by direct measurements of pollen import and foraging activity of T. collina in three selected sites: Pollen traps installed at nests in high-density Sepilok captured significantly more corbicular pollen than colonies in low-density Deramakot. At the same time, morning foraging activity was also greater in Sepilok, indicating a regulatory increase in foraging in response to high pollen availability. We conclude that the abundance of stingless bees in forests in Sabah is chiefly dependent on the local availability of food resources. Bee populations strongly benefit from edge effects and increased foraging habitat diversity. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00442-001-0848-6.

Symptoms to pollen and fruits early in life and allergic disease at 4 years of age.

PubMed

Mai, X-M; Neuman, A; Ostblom, E; Pershagen, G; Nordvall, L; Almqvist, C; van Hage, M; Wickman, M

2008-11-01

The predictive value of reported early symptoms to pollen or fruits on later allergic disease is unclear. Our aim is to evaluate if symptoms to pollen and/or to fruits early in life are associated with allergic disease and sensitization to pollen at 4 years. The study included 3619 children from the Barn (Children), Allergy, Milieu, Stockholm, Epidemiology project (BAMSE) birth cohort. Reported symptoms of wheeze, sneeze or rash to birch, grass or weed, symptoms (vomiting, diarrhea, rash, facial edema, sneeze, or wheeze) to fruits including tree-nuts at 1 or 2 years of age, and definitions of asthma, rhinitis and eczema at 4 years were derived from questionnaire data. Sensitization to pollen allergens was defined as allergen-specific IgE-antibodies to any pollen (birch/timothy/mugwort) > or =0.35 kU(A)/l. At 1 or 2 years of age, 6% of the children were reported to have pollen-related symptoms, 6% had symptoms to fruits, and 1.4% to both pollen and fruits. Children with symptoms to both pollen and fruits at 1 or 2 years of age had an increased risk for sensitization to any pollen allergen at age 4 (OR(adj) = 4.4, 95% CI = 2.1-9.2). This group of children also had a substantially elevated risk for developing any allergic disease (asthma, rhinitis, or eczema) at 4 years irrespective of sensitization to pollen (OR(adj) = 8.6, 95% CI = 4.5-16.4). The prevalence of reported symptoms to pollen and fruits is very low in early childhood. However, children with early symptoms to both pollen and fruits appear to have a markedly elevated risk for allergic disease.

Evolutionarily conserved phenylpropanoid pattern on angiosperm pollen.

PubMed

Fellenberg, Christin; Vogt, Thomas

2015-04-01

The male gametophyte of higher plants appears as a solid box containing the essentials to transmit genetic material to the next generation. These consist of haploid generative cells that are required for reproduction, and an invasive vegetative cell producing the pollen tube, both mechanically protected by a rigid polymer, the pollen wall, and surrounded by a hydrophobic pollen coat. This coat mediates the direct contact to the biotic and abiotic environments. It contains a mixture of compounds required not only for fertilization but also for protection against biotic and abiotic stressors. Among its metabolites, the structural characteristics of two types of phenylpropanoids, hydroxycinnamic acid amides and flavonol glycosides, are highly conserved in Angiosperm pollen. Structural and functional aspects of these compounds will be discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Honey bees preferentially consume freshly-stored pollen

PubMed Central

Goodall, Craig; Downs, Alexandra M.; Sheenan, Timothy H.

2017-01-01

Honey bees (Apis mellifera) collect and store both honey and pollen in preserved forms. Pollen storage involves the addition of honey or nectar and oral secretions to pollen granules. It is controversial whether the duration of pollen storage alters the palatability or nutritive value of the pollen storage medium. We examined how bees utilize different-aged stored pollen during an extended pollen flow. The deposition of pollen into wax cells and subsequent consumption were monitored daily on 18 brood frames from 6 colonies over an 8d observation period. Despite a greater abundance of older stored pollen cells on brood frames, bees showed a marked preference for the consumption of freshly-stored pollen. Two to four day-old pollen cell contents were significantly more likely to be consumed, while pollen cell contents more than seven days old were eaten at much lower rates. Similar experiments that controlled for cell abundance and spatial effects using cage assays yielded the same result. One day-old stored pollen was consumed approximately three times more often than 10d-old stored pollen, and two times more often than 5d-old stored pollen. These consumption preferences for freshly-stored pollen occurred despite a lack of clear developmental advantages. Young adult workers reared for 7 days on 1d-, 5d-, or 10d-old stored pollen showed no difference in body mass, stored pollen consumption, hindgut fecal material accumulation, or hypopharyngeal gland (HPG) protein titers, suggesting that different-aged pollen stores did not vary in their nutritional value to adult bees. These findings are inconsistent with the hypothesis promoting a period of microbially-mediated, “beebread maturation” that results in greater palatability or nutritive value for aged pollen stores. Rather, stored pollen that is not eaten in the first few days accumulates as excess stores preserved in a less preferred, but nutritionally-similar state. PMID:28430801

Honey bees preferentially consume freshly-stored pollen.

PubMed

Carroll, Mark J; Brown, Nicholas; Goodall, Craig; Downs, Alexandra M; Sheenan, Timothy H; Anderson, Kirk E

2017-01-01

Honey bees (Apis mellifera) collect and store both honey and pollen in preserved forms. Pollen storage involves the addition of honey or nectar and oral secretions to pollen granules. It is controversial whether the duration of pollen storage alters the palatability or nutritive value of the pollen storage medium. We examined how bees utilize different-aged stored pollen during an extended pollen flow. The deposition of pollen into wax cells and subsequent consumption were monitored daily on 18 brood frames from 6 colonies over an 8d observation period. Despite a greater abundance of older stored pollen cells on brood frames, bees showed a marked preference for the consumption of freshly-stored pollen. Two to four day-old pollen cell contents were significantly more likely to be consumed, while pollen cell contents more than seven days old were eaten at much lower rates. Similar experiments that controlled for cell abundance and spatial effects using cage assays yielded the same result. One day-old stored pollen was consumed approximately three times more often than 10d-old stored pollen, and two times more often than 5d-old stored pollen. These consumption preferences for freshly-stored pollen occurred despite a lack of clear developmental advantages. Young adult workers reared for 7 days on 1d-, 5d-, or 10d-old stored pollen showed no difference in body mass, stored pollen consumption, hindgut fecal material accumulation, or hypopharyngeal gland (HPG) protein titers, suggesting that different-aged pollen stores did not vary in their nutritional value to adult bees. These findings are inconsistent with the hypothesis promoting a period of microbially-mediated, "beebread maturation" that results in greater palatability or nutritive value for aged pollen stores. Rather, stored pollen that is not eaten in the first few days accumulates as excess stores preserved in a less preferred, but nutritionally-similar state.

Pollen-mediated gene flow from transgenic cotton is constrained by physical isolation measures.

PubMed

Yan, Shuo; Zhu, Weilong; Zhang, Boyu; Zhang, Xinmi; Zhu, Jialin; Shi, Jizhe; Wu, Pengxiang; Wu, Fengming; Li, Xiangrui; Zhang, Qingwen; Liu, Xiaoxia

2018-02-12

The public concern about pollen-mediated gene flow (PGF) from genetically modified (GM) crops to non-GM crops heats up in recent years over China. In the current study, we conducted greenhouse and field experiments to measure PGF with various physical isolation measures, including 90, 80, 60 and 40 holes/cm 2 separation nets and Sorghum bicolor, Zea mays and Lycopersicon esculentum separation crops between GM cotton and non-GM line (Shiyuan321) by seed DNA test during 2013 to 2015, and pollen grain dyeing was also conducted to assess the pollen flow in greenhouse during 2013. Our results revealed that (1) PGF varied depending on the physical isolation measures. PGF was the lowest with 90 holes/cm 2 separation net and S. bicolor separation crop, and the highest with 40 holes/cm 2 separation net and no isolation measure. (2) Similar to PGF results, 90 holes/cm 2 separation net and S. bicolor separation crop could minimize the pollen dispersal. (3) PGF declined exponentially with increasing distance between GM cotton and Shiyuan321. Because of the production mode of farm household (limited cultivated area) in China, our study is particularly important, which is not only benefit for constraining PGF, but also has potential application value in practical production and the scientific researches.

Peroxynitrite mediates programmed cell death both in papillar cells and in self-incompatible pollen in the olive (Olea europaea L.)

PubMed Central

Serrano, Irene; Romero-Puertas, María C.; Rodríguez-Serrano, María; Sandalio, Luisa M.; Olmedilla, Adela

2012-01-01

Programmed cell death (PCD) has been found to be induced after pollination both in papillar cells and in self-incompatible pollen in the olive (Olea europaea L.). Reactive oxygen species (ROS) and nitric oxide (NO) are known to be produced in the pistil and pollen during pollination but their contribution to PCD has so far remained elusive. The possible role of ROS and NO was investigated in olive pollen–pistil interaction during free and controlled pollination and it was found that bidirectional interaction appears to exist between the pollen and the stigma, which seems to regulate ROS and NO production. Biochemical evidence strongly suggesting that both O2˙− and NO are essential for triggering PCD in self-incompatibility processes was also obtained. It was observed for the first time that peroxynitrite, a powerful oxidizing and nitrating agent generated during a rapid reaction between O2˙− and NO, is produced during pollination and that this is related to an increase in protein nitration which, in turn, is strongly associated with PCD. It may be concluded that peroxynitrite mediates PCD during pollen–pistil interaction in Olea europaea L. both in self-incompatible pollen and papillar cells. PMID:22140239

THE DISPERSION OF HERBACEOUS PLANT POLLEN IN ITO CITY, SHIZUOKA.

PubMed

Fujii, Mayumi; Makiyama, Kiyoshi; Okazaki, Kenji; Hisamatsu, Kenichi

2016-08-01

Airborne pollen was examined in Ito City, Shizuoka for the purpose of treatment and prophylaxis pollen allergies because the patients with pollen allergy to herbaceous plants have recently increased. Setting up a Durham's sampler, we measured airborne pollen identified and classified: Poaceae, Polygonaceae, Amaranthaceae, Urticaceae, Cannabaceae, Ambrosia and Artemisia indica.We studied whether each airborne pollen count has something to do with weather condition (2004-2015). Average total airborne Poaceae pollen count and standard deviation from January to June was 19.4±5.5 cells/cm(2), average total airborne Polygonaceae pollen count and standard deviation from April to September was 11.6±13.4 cells/cm(2). Airborne Poaceae, Amaranthaceae, Cannabaceae, Uriticaceae. Ambrosia and Artamisia indica pollen count from July to Deccember in order: 34.0±15.5 cells/cm(2), 1.3±1.1 cells/cm(2), 8.7±6.4cells/cm(2), 4.9±6.4 cells/cm(2), 10.5±7.8 cells/cm(2), and 13.6±16.3 cells/cm(2).Cannabaceae admitted that its airborne pollen count has negative correlation to the rainfall.Artemisia indica admitted that its airborne pollen count has negative correlation to the average temperature. Herbaceous plants pollen doesn't cause allergies because it is much less than tree pollen in ItoCity.It is thought that the diversity of the plants keep the people from having a serious allergy to pollen with awarm weather in this area.

New EAACI definition on pollen season mirrors symptom load for grass and birch pollen-induced allergic rhinitis.

PubMed

Karatzas, Kostas; Katsifarakis, Nikos; Riga, Marina; Werchan, Barbora; Werchan, Matthias; Berger, Uwe; Pfaar, Oliver; Bergmann, Karl-Christian

2018-05-23

The use of allergen immunotherapy (AIT) for allergic rhinitis and its clinical efficacy in clinical trials depends on the effective determination of pollen allergens exposure time-periods. We evaluate pollen data from Germany to examine the new definitions on pollen season and peak pollen period start and end as proposed by the European Academy of Allergy and Clinical Immunology (EAACI) in a recently published Position Paper. The aim was to demonstrate the ability of these definitions to mirror symptom loads for grass and birch pollen-induced allergic rhinitis based on real-life data. Data coming from four Pollen monitoring stations in the Berlin and Brandenburg area in Germany and for 3 years (2014 - 2016) were used to investigate the correlation of season definitions, birch and grass pollen counts and total nasal symptom and mediation scores as reported by patients in "Patients Hayfever Diaries" (PHDs). After the identification of pollen periods on the basis of the EACCI criteria, a statistical analysis was employed, followed by a detailed graphical investigation. The analysis revealed that the definitions of pollen season as well as peak pollen period start and end as proposed by the EAACI are correlated to symptom loads for grass and birch pollen-induced allergic rhinitis reported by patients in PHDs. Based on our analysis, the validity of the EAACI definitions on pollen season is confirmed. Their use is recommended in future clinical trials on AIT as well as in daily routine for optimal patient care. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Persistence of long-distance, insect-mediated pollen movement for a tropical canopy tree species in remnant forest patches in an urban landscape.

PubMed

Noreen, A M E; Niissalo, M A; Lum, S K Y; Webb, E L

2016-12-01

As deforestation and urbanization continue at rapid rates in tropical regions, urban forest patches are essential repositories of biodiversity. However, almost nothing is known about gene flow of forest-dependent tree species in urban landscapes. In this study, we investigated gene flow in the insect-pollinated, wind-dispersed tropical tree Koompassia malaccensis in and among three remnant forest patches in the urbanized landscape of Singapore. We genotyped the vast majority of adults (N=179) and a large number of recruits (N=2103) with 8 highly polymorphic microsatellite markers. Spatial genetic structure of the recruit and adult cohorts was significant, showing routine gene dispersal distances of ~100-400 m. Parentage analysis showed that 97% of recruits were within 100 m of their mother tree, and a high frequency of relatively short-distance pollen dispersal (median ~143-187 m). Despite routine seed and pollen dispersal distances of within a few hundred meters, interpatch gene flow occurred between all patches and was dominated by pollen movement: parentage analysis showed 76 pollen versus 2 seed interpatch dispersal events, and the seedling neighborhood model estimated ~1-6% seed immigration and ~21-46% pollen immigration rates, depending on patch. In addition, the smallest patch (containing five adult K. malaccensis trees) was entirely surrounded by >2.5 km of 'impervious' substrate, yet had the highest proportional pollen and seed immigration estimates of any patch. Hence, contrary to our hypothesis, insect-mediated gene flow persisted across an urban landscape, and several of our results also parallel key findings from insect-pollinated canopy trees sampled in mixed agricultural-forest landscapes.

There is more to pollinator-mediated selection than pollen limitation.

PubMed

Sletvold, Nina; Agren, Jon

2014-07-01

Spatial variation in pollinator-mediated selection (Δβpoll ) is a major driver of floral diversification, but we lack a quantitative understanding of its link to pollen limitation (PL) and net selection on floral traits. For 2-5 years, we quantified Δβpoll on floral traits in two populations each of two orchid species differing in PL. In both species, spatiotemporal variation in Δβpoll explained much of the variation in net selection. Selection was consistently stronger and the proportion that was pollinator-mediated was higher in the severely pollen-limited deceptive species than in the rewarding species. Within species, variation in PL could not explain variation in Δβpoll for any trait, indicating that factors influencing the functional relationship between trait variation and pollination success govern a major part of the observed variation in Δβpoll . Separating the effects of variation in mean interaction intensity and in the functional significance of traits will be necessary to understand spatiotemporal variation in selection exerted by the biotic environment. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Receptor-Like Kinase RUPO Interacts with Potassium Transporters to Regulate Pollen Tube Growth and Integrity in Rice

PubMed Central

Liu, Lingtong; Zheng, Canhui; Kuang, Baijan; Wei, Liqin; Yan, Longfeng; Wang, Tai

2016-01-01

During sexual reproduction of flowering plants, the pollen tube grows fast and over a long distance within the pistil to deliver two sperms for double fertilization. Growing plant cells need to communicate constantly with external stimuli as well as monitor changes in surface tension of the cell wall and plasma membrane to coordinate these signals and internal growth machinery; however, the underlying mechanisms remain largely unknown. Here we show that the rice member of plant-specific receptor-like kinase CrRLK1Ls subfamily, Ruptured Pollen tube (RUPO), is specifically expressed in rice pollen. RUPO localizes to the apical plasma membrane and vesicle of pollen tubes and is required for male gamete transmission. K+ levels were greater in pollen of homozygous CRISPR-knockout lines than wild-type plants, and pollen tubes burst shortly after germination. We reveal the interaction of RUPO with high-affinity potassium transporters. Phosphorylation of RUPO established and dephosphorylation abolished the interaction. These results have revealed the receptor-like kinase as a regulator of high-affinity potassium transporters via phosphorylation-dependent interaction, and demonstrated a novel receptor-like kinase signaling pathway that mediates K+ homeostasis required for pollen tube growth and integrity. PMID:27447945

Influence of Electric Fields and Conductivity on Pollen Tube Growth assessed via Electrical Lab-on-Chip

PubMed Central

Agudelo, Carlos; Packirisamy, Muthukumaran; Geitmann, Anja

2016-01-01

Pollen tubes are polarly growing plant cells that are able to rapidly respond to a combination of chemical, mechanical, and electrical cues. This behavioural feature allows them to invade the flower pistil and deliver the sperm cells in highly targeted manner to receptive ovules in order to accomplish fertilization. How signals are perceived and processed in the pollen tube is still poorly understood. Evidence for electrical guidance in particular is vague and highly contradictory. To generate reproducible experimental conditions for the investigation of the effect of electric fields on pollen tube growth we developed an Electrical Lab-on-Chip (ELoC). Pollen from the species Camellia displayed differential sensitivity to electric fields depending on whether the entire cell or only its growing tip was exposed. The response to DC fields was dramatically higher than that to AC fields of the same strength. However, AC fields were found to restore and even promote pollen growth. Surprisingly, the pollen tube response correlated with the conductivity of the growth medium under different AC frequencies—consistent with the notion that the effect of the field on pollen tube growth may be mediated via its effect on the motion of ions. PMID:26804186

Genome duplication and the evolution of conspecific pollen precedence.

PubMed

Baldwin, Sarah J; Husband, Brian C

2011-07-07

Conspecific pollen precedence can be a strong reproductive barrier between polyploid and diploid species, but the role of genome multiplication in the evolution of this barrier has not been investigated. Here, we examine the direct effect of genome duplication on the evolution of pollen siring success in tetraploid Chamerion angustifolium. To separate the effects of genome duplication from selection after duplication, we compared pollen siring success of synthesized tetraploids (neotetraploids) with that of naturally occurring tetraploids by applying 2x, 4x (neo or established) or 2x + 4x pollen to diploid and tetraploid flowers. Seed set increased in diploids and decreased in both types of tetraploids as the proportion of pollen from diploid plants increased. Based on offspring ploidy from mixed-ploidy pollinations, pollen of the maternal ploidy always sired the majority of offspring but was strongest in established tetraploids and weakest in neotetraploids. Pollen from established tetraploids had significantly higher siring rates than neotetraploids when deposited on diploid (4x(est) = 47.2%, 4x(neo) = 27.1%) and on tetraploid recipients (4x(est) = 91.9%, 4x(neo) = 56.0%). Siring success of established tetraploids exceeded that of neotetraploids despite having similar pollen production per anther and pollen diameter. Our results suggest that, while pollen precedence can arise in association with the duplication event, the strength of polyploid siring success evolves after the duplication event.

High Environmental Ozone Levels Lead to Enhanced Allergenicity of Birch Pollen

PubMed Central

Beck, Isabelle; Jochner, Susanne; Gilles, Stefanie; McIntyre, Mareike; Buters, Jeroen T. M.; Schmidt-Weber, Carsten; Behrendt, Heidrun; Ring, Johannes; Menzel, Annette; Traidl-Hoffmann, Claudia

2013-01-01

Background Evidence is compelling for a positive correlation between climate change, urbanisation and prevalence of allergic sensitisation and diseases. The reason for this association is not clear to date. Some data point to a pro-allergenic effect of anthropogenic factors on susceptible individuals. Objectives To evaluate the impact of urbanisation and climate change on pollen allergenicity. Methods Catkins were sampled from birch trees from different sites across the greater area of Munich, pollen were isolated and an urbanisation index, NO2 and ozone exposure were determined. To estimate pollen allergenicity, allergen content and pollen-associated lipid mediators were measured in aqueous pollen extracts. Immune stimulatory and modulatory capacity of pollen was assessed by neutrophil migration assays and the potential of pollen to inhibit dendritic cell interleukin-12 response. In vivo allergenicity was assessed by skin prick tests. Results The study revealed ozone as a prominent environmental factor influencing the allergenicity of birch pollen. Enhanced allergenicity, as assessed in skin prick tests, was mirrored by enhanced allergen content. Beyond that, ozone induced changes in lipid composition and chemotactic and immune modulatory potential of the pollen. Higher ozone-exposed pollen was characterised by less immune modulatory but higher immune stimulatory potential. Conclusion It is likely that future climate change along with increasing urbanisation will lead to rising ozone concentrations in the next decades. Our study indicates that ozone is a crucial factor leading to clinically relevant enhanced allergenicity of birch pollen. Thus, with increasing temperatures and increasing ozone levels, also symptoms of pollen allergic patients may increase further. PMID:24278250

SCFSLF-mediated cytosolic degradation of S-RNase is required for cross-pollen compatibility in S-RNase-based self-incompatibility in Petunia hybrida

PubMed Central

Liu, Wei; Fan, Jiangbo; Li, Junhui; Song, Yanzhai; Li, Qun; Zhang, Yu'e; Xue, Yongbiao

2014-01-01

Many flowering plants adopt self-incompatibility (SI) to maintain their genetic diversity. In species of Solanaceae, Plantaginaceae, and Rosaceae, SI is genetically controlled by a single S-locus with multiple haplotypes. The S-locus has been shown to encode S-RNases expressed in pistil and multiple SLF (S-locus F-box) proteins in pollen controlling the female and male specificity of SI, respectively. S-RNases appear to function as a cytotoxin to reject self-pollen. In addition, SLFs have been shown to form SCF (SKP1/Cullin1/F-box) complexes to serve as putative E3 ubiquitin ligase to interact with S-RNases. Previously, two different mechanisms, the S-RNase degradation and the S-RNase compartmentalization, have been proposed as the restriction mechanisms of S-RNase cytotoxicity allowing compatible pollination. In this study, we have provided several lines of evidence in support of the S-RNase degradation mechanism by a combination of cellular, biochemical and molecular biology approaches. First, both immunogold labeling and subcellular fractionation assays showed that two key pollen SI factors, PhS3L-SLF1 and PhSSK1 (SLF-interacting SKP1-like1) from Petunia hybrida, a Solanaceous species, are co-localized in cytosols of both pollen grains and tubes. Second, PhS3L-RNases are mainly detected in the cytosols of both self and non-self-pollen tubes after pollination. Third, we found that PhS-RNases selectively interact with PhSLFs by yeast two-hybrid and co-immunoprecipitation assays. Fourth, S-RNases are specifically degraded in compatible pollen tubes by non-self SLF action. Taken together, our results demonstrate that SCFSLF-mediated non-self S-RNase degradation occurs in the cytosol of pollen tube through the ubiquitin/26S proteasome system serving as the major mechanism to neutralize S-RNase cytotoxicity during compatible pollination in P. hybrida. PMID:25101113

Investigating Pollen and Gene Flow of WYMV-Resistant Transgenic Wheat N12-1 Using a Dwarf Male-Sterile Line as the Pollen Receptor.

PubMed

Dong, Shanshan; Liu, Yan; Yu, Cigang; Zhang, Zhenhua; Chen, Ming; Wang, Changyong

2016-01-01

Pollen-mediated gene flow (PMGF) is the main mode of transgene flow in flowering plants. The study of pollen and gene flow of transgenic wheat can help to establish the corresponding strategy for preventing transgene escape and contamination between compatible genotypes in wheat. To investigate the pollen dispersal and gene flow frequency in various directions and distances around the pollen source and detect the association between frequency of transgene flow and pollen density from transgenic wheat, a concentric circle design was adopted to conduct a field experiment using transgenic wheat with resistance to wheat yellow mosaic virus (WYMV) as the pollen donor and dwarf male-sterile wheat as the pollen receptor. The results showed that the pollen and gene flow of transgenic wheat varied significantly among the different compass sectors. A higher pollen density and gene flow frequency was observed in the downwind SW and W sectors, with average frequencies of transgene flow of 26.37 and 23.69% respectively. The pollen and gene flow of transgenic wheat declined dramatically with increasing distance from its source. Most of the pollen grains concentrated within 5 m and only a few pollen grains were detected beyond 30 m. The percentage of transgene flow was the highest where adjacent to the pollen source, with an average of 48.24% for all eight compass directions at 0 m distance. Transgene flow was reduced to 50% and 95% between 1.61 to 3.15 m, and 10.71 to 20.93 m, respectively. Our results suggest that climate conditions, especially wind direction, may significantly affect pollen dispersal and gene flow of wheat. The isolation-by-distance model is one of the most effective methods for achieving stringent transgene confinement in wheat. The frequency of transgene flow is directly correlated with the relative density of GM pollen grains in air currents, and pollen competition may be a major factor influencing transgene flow.

Investigating Pollen and Gene Flow of WYMV-Resistant Transgenic Wheat N12-1 Using a Dwarf Male-Sterile Line as the Pollen Receptor

PubMed Central

Dong, Shanshan; Liu, Yan; Yu, Cigang; Zhang, Zhenhua; Chen, Ming; Wang, Changyong

2016-01-01

Pollen-mediated gene flow (PMGF) is the main mode of transgene flow in flowering plants. The study of pollen and gene flow of transgenic wheat can help to establish the corresponding strategy for preventing transgene escape and contamination between compatible genotypes in wheat. To investigate the pollen dispersal and gene flow frequency in various directions and distances around the pollen source and detect the association between frequency of transgene flow and pollen density from transgenic wheat, a concentric circle design was adopted to conduct a field experiment using transgenic wheat with resistance to wheat yellow mosaic virus (WYMV) as the pollen donor and dwarf male-sterile wheat as the pollen receptor. The results showed that the pollen and gene flow of transgenic wheat varied significantly among the different compass sectors. A higher pollen density and gene flow frequency was observed in the downwind SW and W sectors, with average frequencies of transgene flow of 26.37 and 23.69% respectively. The pollen and gene flow of transgenic wheat declined dramatically with increasing distance from its source. Most of the pollen grains concentrated within 5 m and only a few pollen grains were detected beyond 30 m. The percentage of transgene flow was the highest where adjacent to the pollen source, with an average of 48.24% for all eight compass directions at 0 m distance. Transgene flow was reduced to 50% and 95% between 1.61 to 3.15 m, and 10.71 to 20.93 m, respectively. Our results suggest that climate conditions, especially wind direction, may significantly affect pollen dispersal and gene flow of wheat. The isolation-by-distance model is one of the most effective methods for achieving stringent transgene confinement in wheat. The frequency of transgene flow is directly correlated with the relative density of GM pollen grains in air currents, and pollen competition may be a major factor influencing transgene flow. PMID:26975052

All 17 S-locus F-box proteins of the S2 - and S3 -haplotypes of Petunia inflata are assembled into similar SCF complexes with a specific function in self-incompatibility.

PubMed

Li, Shu; Williams, Justin S; Sun, Penglin; Kao, Teh-Hui

2016-09-01

The collaborative non-self-recognition model for S-RNase-based self-incompatibility predicts that multiple S-locus F-box proteins (SLFs) produced by pollen of a given S-haplotype collectively mediate ubiquitination and degradation of all non-self S-RNases, but not self S-RNases, in the pollen tube, thereby resulting in cross-compatible pollination but self-incompatible pollination. We had previously used pollen extracts containing GFP-fused S2 -SLF1 (SLF1 with an S2 -haplotype) of Petunia inflata for co-immunoprecipitation (Co-IP) and mass spectrometry (MS), and identified PiCUL1-P (a pollen-specific Cullin1), PiSSK1 (a pollen-specific Skp1-like protein) and PiRBX1 (a conventional Rbx1) as components of the SCF(S) (2-) (SLF) (1) complex. Using pollen extracts containing PiSSK1:FLAG:GFP for Co-IP/MS, we identified two additional SLFs (SLF4 and SLF13) that were assembled into SCF(SLF) complexes. As 17 SLF genes (SLF1 to SLF17) have been identified in S2 and S3 pollen, here we examined whether all 17 SLFs are assembled into similar complexes and, if so, whether these complexes are unique to SLFs. We modified the previous Co-IP/MS procedure, including the addition of style extracts from four different S-genotypes to pollen extracts containing PiSSK1:FLAG:GFP, to perform four separate experiments. The results taken together show that all 17 SLFs and an SLF-like protein, SLFLike1 (encoded by an S-locus-linked gene), co-immunoprecipitated with PiSSK1:FLAG:GFP. Moreover, of the 179 other F-box proteins predicted by S2 and S3 pollen transcriptomes, only a pair with 94.9% identity and another pair with 99.7% identity co-immunoprecipitated with PiSSK1:FLAG:GFP. These results suggest that SCF(SLF) complexes have evolved specifically to function in self-incompatibility. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

The microtubule cytoskeleton and pollen tube Golgi vesicle system are required for in vitro S-RNase internalization and gametic self-incompatibility in apple.

PubMed

Meng, Dong; Gu, Zhaoyu; Yuan, Hui; Wang, Aide; Li, Wei; Yang, Qing; Zhu, Yuandi; Li, Tianzhong

2014-05-01

S-RNase is the female determinant of gametophytic self-incompatibility in apple and is usually considered to be the reason for rejection of pollen. In this study, we investigated the role of microtubules (MTs) in internalization of S-RNases by pollen tubes cultured in vitro. The results showed that S-RNase was imported into the pollen tube where it inhibits pollen tube growth, and that S-RNase is co-localized with the Golgi vesicle during the internalization process. Moreover, MT depolymerization is observed following accumulation of S-RNases in the pollen cytosol. On the other hand, S-RNase was prevented from entering the pollen tube when the pollen was treated with the actin filament (AF) inhibitor latrunculin A (LatA), the MT inhibitor oryzalin, or the MT stabilizer taxol at subtoxic concentrations. These hindered the construction of the MT, with pollen tubes capable of growth under these conditions. Pollen tubes showed improved growth in self-pollinated styles that were pre-treated with taxol. This suggests that cytoskeleton antagonists can prevent S-RNase-mediated inhibition of pollen tubes in vivo by blocking S-RNase internalization. These results suggest that an intact and dynamic cytoskeleton is required for the in vitro internalization of S-RNase, as shown by the effects of various cytoskeleton inhibitors. S-RNase internalization takes place via a membrane/cytoskeleton-based Golgi vesicle system, which can also affect self-incompatibility in apple.

Pollen Concentration in the Atmosphere of Abha City, Saudi Arabia and its Relationship with Meteorological Parameters

NASA Astrophysics Data System (ADS)

Alwadie, Hussein M.

A qualitative and quantitative evaluation of pollen concentration in the atmosphere of Abha city, Saudi Arabia with the relation to meteorological parameters is presented. Investigations were undertaken from January to December 2006 using a Burkard 7 day volumetric spore trap. A total of 6,492 pollen grains m-3 belonging to 50 pollen taxa was detected. Poaceae represented 55.1% of total pollen, Leguminosae (11.7%), Compositae (6.1%), Solanaceae (4.6%) and Cupressaceae (4.2%). Pollen grains were found throughout the year. July represented the highest peak of pollen number and also the highest pollen taxa. The monthly variation of pollen taxa and their relationship to meteorological parameters were investigated. It was found that the pollen concentration is positively correlated with temperature and negatively correlated with rainfall, relative humidity and wind velocity. May-September represented the months of highest pollen number (95% of total pollen).

Simulated environmental criticalities affect transglutaminase of Malus and Corylus pollens having different allergenic potential.

PubMed

Iorio, Rosa Anna; Di Sandro, Alessia; Paris, Roberta; Pagliarani, Giulia; Tartarini, Stefano; Ricci, Giampaolo; Serafini-Fracassini, Donatella; Verderio, Elisabetta; Del Duca, Stefano

2012-02-01

Increases in temperature and air pollution influence pollen allergenicity, which is responsible for the dramatic raise in respiratory allergies. To clarify possible underlying mechanisms, an anemophilous pollen (hazel, Corylus avellana), known to be allergenic, and an entomophilous one (apple, Malus domestica), the allergenicity of which was not known, were analysed. The presence also in apple pollen of known fruit allergens and their immunorecognition by serum of an allergic patient were preliminary ascertained, resulting also apple pollen potentially allergenic. Pollens were subjected to simulated stressful conditions, provided by changes in temperature, humidity, and copper and acid rain pollution. In the two pollens exposed to environmental criticalities, viability and germination were negatively affected and different transglutaminase (TGase) gel bands were differently immunodetected with the polyclonal antibody AtPng1p. The enzyme activity increased under stressful treatments and, along with its products, was found to be released outside the pollen with externalisation of TGase being predominant in C. avellana, whose grain presents a different cell wall composition with respect to that of M. domestica. A recombinant plant TGase (AtPng1p) stimulated the secreted phospholipase A(2) (sPLA(2)) activity, that in vivo is present in human mucosa and is involved in inflammation. Similarly, stressed pollen, hazel pollen being the most efficient, stimulated to very different extent sPLA(2) activity and putrescine conjugation to sPLA(2). We propose that externalised pollen TGase could be one of the mediators of pollen allergenicity, especially under environmental stress induced by climate changes.

Characterization of cogon grass (Imperata cylindrica) pollen extract and preliminary analysis of grass group 1, 4 and 5 homologues using monoclonal antibodies to Phleum pratense.

PubMed

Kumar, L; Sridhara, S; Singh, B P; Gangal, S V

1998-11-01

Previous studies have established the role of Imperata cylindrica (Ic) pollen in type I allergic disorders. However, no systematic information is available on the allergen composition of Ic pollen extract. To characterize the IgE-binding proteins of Ic pollen extract and to detect the presence of grass group 1, 4 and 5 allergen homologues, if any. Pollen extract of Ic was analyzed by in vivo and in vitro procedures such as intradermal tests (ID), enzyme-linked immunosorbent assay (ELISA), ELISA-inhibition, thin-layer isoelectric focusing (TLIEF), sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Dot blot assay was carried out to check the presence of well-known group 1, 4, and 5 allergen homologues in Ic pollen extract. Out of 303 respiratory allergies patients skin-tested, 27 showed sensitivity to Ic pollen extract. Specific IgE levels were elevated in all 15 serum samples tested. The extract prepared for this study was found to be highly potent since it required only 400 ng of homologous proteins for 50% inhibition of binding in ELISA inhibition assays. TLIEF of Ic pollen extract showed 44 silver-stained bands (pI 3.5-7.0) while SDS-PAGE resolved it into 24 Coomassie-Brilliant-Blue-stained bands (MW 100-10 kD). Immunoblotting with individual patient sera recognized 7 major IgE-binding bands (MW 85, 62, 57, 43, 40, 28 and 16 kD) in Ic pollen extract. A panel of monoclonal antibodies, specific to group 1, 4 and 5 allergens from Phleum pratense pollen extract identified group 5 and group 4 homologues in Ic pollen extract. Ic pollen extract was characterized for the protein profile by TLIEF and SDS-PAGE. IgE reactivity was determined by ELISA and immunoblot. Monoclonal antibodies to group 5 and group 4 allergens reacted weakly showing that this pollen contains group 5 and group 4 homologous allergens.

Evaluation of eicosanoids in nasal lavage as biomarkers of inflammation in patients with allergic rhinitis

PubMed Central

Górski, Paweł; Antczak, Adam

2014-01-01

Introduction Cysteinyl leukotrienes (cys-LTs), 8-isoprostane and prostaglandin E2 (PGE2) constitute fundamental mediators in allergic inflammation; therefore we wanted to determine the utility of PGE2, 8-isoprostane and cys-LT levels in nasal lavage as biomarkers of allergic inflammation. Material and methods Twenty-one patients with allergic rhinitis (AR) were included on the basis of a positive history of AR symptoms and positive results of skin prick tests to grass pollen allergens. The main exclusion criteria were: uncontrolled asthma, nasal polyps, respiratory infection, tuberculosis, neoplastic and autoimmune diseases, current smoking and immunotherapy. Both outside the pollen season and at the height of the pollen season, total nasal symptom score (TNS-4) was evaluated and the levels of cys-LTs, 8-isoprostane and PGE2 were measured in nasal lavage fluid (NALF). Results Natural allergen stimulation resulted in a significant increase of TNS-4 (p < 0.001) and nasal eosinophilia (p < 0.001). The concentration of PGE2 dominated in the NALF outside the pollen season and decreased significantly at the height of natural exposure (p < 0.01). In contrast, lower baseline concentrations of cys-LTs and 8-isoprostane increased significantly upon allergen stimulation (p < 0.05). There was a significant correlation between mean concentration of PGE2 and eosinophil number in NALF (r = 0.67, p = 0.0439). Conclusions The NALF concentrations of cys-LTs and 8-isoprostane change simultaneously with TNS-4 and nasal eosinophilia. However, due to the lack of any significant correlation, their utility as markers of allergic rhinitis should be warily considered. The decrease of PGE2 concentration in NALF which correlated with nasal eosinophilia may participate in escalation of allergic inflammation and needs further evaluation. PMID:25624848

A Large-Scale Genetic Screen in Arabidopsis to Identify Genes Involved in Pollen Exine Production1[C][W][OA

PubMed Central

Dobritsa, Anna A.; Geanconteri, Aliza; Shrestha, Jay; Carlson, Ann; Kooyers, Nicholas; Coerper, Daniel; Urbanczyk-Wochniak, Ewa; Bench, Bennie J.; Sumner, Lloyd W.; Swanson, Robert; Preuss, Daphne

2011-01-01

Exine, the outer plant pollen wall, has elaborate species-specific patterns, provides a protective barrier for male gametophytes, and serves as a mediator of strong and species-specific pollen-stigma adhesion. Exine is made of sporopollenin, a material remarkable for its strength, elasticity, and chemical durability. The chemical nature of sporopollenin, as well as the developmental mechanisms that govern its assembly into diverse patterns in different species, are poorly understood. Here, we describe a simple yet effective genetic screen in Arabidopsis (Arabidopsis thaliana) that was undertaken to advance our understanding of sporopollenin synthesis and exine assembly. This screen led to the recovery of mutants with a variety of defects in exine structure, including multiple mutants with novel phenotypes. Fifty-six mutants were selected for further characterization and are reported here. In 14 cases, we have mapped defects to specific genes, including four with previously demonstrated or suggested roles in exine development (MALE STERILITY2, CYP703A2, ANTHER-SPECIFIC PROTEIN6, TETRAKETIDE α-PYRONE REDUCTASE/DIHYDROFLAVONOL-4-REDUCTASE-LIKE1), and a number of genes that have not been implicated in exine production prior to this screen (among them, fatty acid ω-hydroxylase CYP704B1, putative glycosyl transferases At1g27600 and At1g33430, 4-coumarate-coenzyme A ligase 4CL3, polygalacturonase QUARTET3, novel gene At5g58100, and nucleotide-sugar transporter At5g65000). Our study illustrates that morphological screens of pollen can be extremely fruitful in identifying previously unknown exine genes and lays the foundation for biochemical, developmental, and evolutionary studies of exine production. PMID:21849515

The effect of anti-IgE treatment on in vitro leukotriene release in children with seasonal allergic rhinitis.

PubMed

Kopp, Matthias Volkmar; Brauburger, Jens; Riedinger, Frank; Beischer, Dorothee; Ihorst, Gabriele; Kamin, Wolfgang; Zielen, Stefan; Bez; Friedrichs, Frank; Von Berg, Andrea; Gerhold, Kerstin; Hamelmann, Eckard; Hultsch; Kuehr, Joachim

2002-11-01

Binding of allergens with IgE to the IgE receptors on mast cells and basophils results in the release of inflammatory mediators as sulfidoleukotrienes (SLTs), triggering allergic cascades that result in allergic symptoms, such as asthma and rhinitis. We sought to investigate whether anti-IgE (Oma-lizumab), a humanized monoclonal anti-IgE antibody, in addition to specific immunotherapy (SIT) affects the leukotriene pathway. Ninety-two children (age range, 6-17 years) with sensitization to birch and grass pollens and with seasonal allergic rhinitis were included in a phase III, placebo- controlled, multicenter clinical study. All subjects were randomized to one of 4 treatment groups. Two groups subcutaneously received birch SIT and 2 groups received grass SIT for at least 14 weeks before the start of the birch pollen season. After 12 weeks of SIT titration, placebo or anti-IgE was added for 24 weeks. The primary clinical efficacy variable was symptom load (ie, the sum of daily symptom severity score and rescue medication score during pollen season). Blood samples taken at baseline and at the end of study treatment after the grass pollen season were used for separation of leukocytes in this substudy. After in vitro stimulation of the blood cells with grass and birch pollen allergens, SLT release (LTC4, LTD4, and LTE4) was quantified by using the ELISA technique. Before the study treatment, SLT release to birch and grass pollen exposure did not differ significantly among the 4 groups. Under treatment with anti-IgE + SIT-grass (n = 23), a lower symptom load occurred during the pollen season compared to placebo + SIT-grass (n = 24, P =.012). The same applied to both groups receiving birch SIT (n = 23 and n = 22, respectively; P =.03). At the end of treatment, the combination of anti-IgE plus grass SIT, as well as anti-IgE plus birch SIT, resulted in significantly lower SLT release after stimulation with the corresponding allergen (416 ng/L [5th-95th percentile, 1-1168] and 207 ng/L [1-860 ng/L], respectively) compared with placebo plus SIT (2490 ng/L [384-6587 ng/L], P =.001; 2489 ng/L [1-5670 ng/L], P =.001). In addition, treatment with anti-IgE was also followed by significantly lower SLT releases to the allergens unrelated to SIT (grass SIT: 300 ng/L [1-2432 ng/L] in response to birch allergen; birch SIT: 1478 ng/L [1-4593 ng/L] in response to grass pollen) in comparison with placebo (grass SIT: 1850 ng/L [1-5499 ng/L], P =.001; birch SIT: 2792 ng/L [154-5839 ng/L], P =.04]. Anti-IgE therapy reduces leukotriene release of peripheral leukocytes stimulated with allergen in children with allergic rhinitis undergoing allergen immunotherapy independent of the type of SIT allergen used.

[Sensitization to Castanea sativa pollen and pollinosis in northern Extremadura (Spain)].

PubMed

Cosmes Martín, P M; Moreno Ancillo, A; Domínguez Noche, C; Gutiérrez Vivas, A; Belmonte Soler, J; Roure Nolla, J M

2005-01-01

Castanea sativa pollen allergy has generally been considered to be uncommon and clinically insignificant. In our geographical area (Plasencia, Cáceres, Spain) Castanea sativa pollen is a major pollen. To determine the atmospheric fluctuations and prevalence of patients sensitized to Castanea pollen in our region and to compare this sensitization with sensitizations to other pollens. Patients with respiratory symptoms attending our outpatient clinic for the first time in 2003 were studied. The patients underwent skin prick tests with commercial extracts of a battery of inhalants including Castanea sativa pollen. Serologic specific IgE to Castanea sativa pollen was determined using the CAP system (Pharmacia and Upjohn, Uppsala, Sweden). Airborne pollen counts in our city were obtained using Cour collection apparatus over a 4-year period (2000 to 2003). The most predominant pollens detected were (mean of the maximal weekly concentrations over 4 years in pollen grains/m3): Quercus 968, Poacea 660, Olea 325, Platanus 229, Pinus 126, Cupresaceae 117, Plantago 109, Alnus 41, Populus 40, Castanea 32. We studied 346 patients (mean age: 24.1 years). In 210 patients with a diagnosis of pollinosis, the percentages of sensitization were: Dactylis glomerata 80.4%, Olea europea 71.9%, Fraxinus excelsior 68%, Plantago lanceolata 62.8%, Chenopodium album 60.9%, Robinia pseudoacacia 49%, Artemisia vulgaris 43.8%, Platanus acerifolia 36.6%, Parietaria judaica 36.1%, Populus nigra 32.3%, Betula alba 27.6%, Quercus ilex 21.4%, Alnus glutinosa 20.9%, Cupressus arizonica 7.6% and Castanea sativa 7.1%. Fifteen patients were sensitized to Castanea sativa and 14 had seasonal rhinoconjunctivitis and asthma. Ten patients had serum specific IgE to Castanea pollen (maximum value: 17.4 Ku/l). Castanea pollen is present in our area in large amounts from the 23rd to the 28th weeks of the year, with a peak pollen count in the 25th week. The most important allergenic pollens in northern Extremadura were Poaceae, Olea europaea and Plantago sp. The prevalence of sensitization to Castanea sativa pollen was very low (7.1%). Most sensitized patients had asthma and polysensitization. Castanea sativa pollen is not a major cause of pollinosis in our area.

Identification of genes specifically or preferentially expressed in maize silk reveals similarity and diversity in transcript abundance of different dry stigmas.

PubMed

Xu, Xiao Hui; Chen, Hao; Sang, Ya Lin; Wang, Fang; Ma, Jun Ping; Gao, Xin-Qi; Zhang, Xian Sheng

2012-07-02

In plants, pollination is a critical step in reproduction. During pollination, constant communication between male pollen and the female stigma is required for pollen adhesion, germination, and tube growth. The detailed mechanisms of stigma-mediated reproductive processes, however, remain largely unknown. Maize (Zea mays L.), one of the world's most important crops, has been extensively used as a model species to study molecular mechanisms of pollen and stigma interaction. A comprehensive analysis of maize silk transcriptome may provide valuable information for investigating stigma functionality. A comparative analysis of expression profiles between maize silk and dry stigmas of other species might reveal conserved and diverse mechanisms that underlie stigma-mediated reproductive processes in various plant species. Transcript abundance profiles of mature silk, mature pollen, mature ovary, and seedling were investigated using RNA-seq. By comparing the transcriptomes of these tissues, we identified 1,427 genes specifically or preferentially expressed in maize silk. Bioinformatic analyses of these genes revealed many genes with known functions in plant reproduction as well as novel candidate genes that encode amino acid transporters, peptide and oligopeptide transporters, and cysteine-rich receptor-like kinases. In addition, comparison of gene sets specifically or preferentially expressed in stigmas of maize, rice (Oryza sativa L.), and Arabidopsis (Arabidopsis thaliana [L.] Heynh.) identified a number of homologous genes involved either in pollen adhesion, hydration, and germination or in initial growth and penetration of pollen tubes into the stigma surface. The comparison also indicated that maize shares a more similar profile and larger number of conserved genes with rice than with Arabidopsis, and that amino acid and lipid transport-related genes are distinctively overrepresented in maize. Many of the novel genes uncovered in this study are potentially involved in stigma-mediated reproductive processes, including genes encoding amino acid transporters, peptide and oligopeptide transporters, and cysteine-rich receptor-like kinases. The data also suggest that dry stigmas share similar mechanisms at early stages of pollen-stigma interaction. Compared with Arabidopsis, maize and rice appear to have more conserved functional mechanisms. Genes involved in amino acid and lipid transport may be responsible for mechanisms in the reproductive process that are unique to maize silk.

Identification of genes specifically or preferentially expressed in maize silk reveals similarity and diversity in transcript abundance of different dry stigmas

PubMed Central

2012-01-01

Background In plants, pollination is a critical step in reproduction. During pollination, constant communication between male pollen and the female stigma is required for pollen adhesion, germination, and tube growth. The detailed mechanisms of stigma-mediated reproductive processes, however, remain largely unknown. Maize (Zea mays L.), one of the world’s most important crops, has been extensively used as a model species to study molecular mechanisms of pollen and stigma interaction. A comprehensive analysis of maize silk transcriptome may provide valuable information for investigating stigma functionality. A comparative analysis of expression profiles between maize silk and dry stigmas of other species might reveal conserved and diverse mechanisms that underlie stigma-mediated reproductive processes in various plant species. Results Transcript abundance profiles of mature silk, mature pollen, mature ovary, and seedling were investigated using RNA-seq. By comparing the transcriptomes of these tissues, we identified 1,427 genes specifically or preferentially expressed in maize silk. Bioinformatic analyses of these genes revealed many genes with known functions in plant reproduction as well as novel candidate genes that encode amino acid transporters, peptide and oligopeptide transporters, and cysteine-rich receptor-like kinases. In addition, comparison of gene sets specifically or preferentially expressed in stigmas of maize, rice (Oryza sativa L.), and Arabidopsis (Arabidopsis thaliana [L.] Heynh.) identified a number of homologous genes involved either in pollen adhesion, hydration, and germination or in initial growth and penetration of pollen tubes into the stigma surface. The comparison also indicated that maize shares a more similar profile and larger number of conserved genes with rice than with Arabidopsis, and that amino acid and lipid transport-related genes are distinctively overrepresented in maize. Conclusions Many of the novel genes uncovered in this study are potentially involved in stigma-mediated reproductive processes, including genes encoding amino acid transporters, peptide and oligopeptide transporters, and cysteine-rich receptor-like kinases. The data also suggest that dry stigmas share similar mechanisms at early stages of pollen-stigma interaction. Compared with Arabidopsis, maize and rice appear to have more conserved functional mechanisms. Genes involved in amino acid and lipid transport may be responsible for mechanisms in the reproductive process that are unique to maize silk. PMID:22748054

Wind tunnel and field assessment of pollen dispersal in soybean [Glycine max (L.) Merr.].

PubMed

Yoshimura, Yasuyuki

2011-01-01

Although genetically modified (GM) soybean has never been cultivated commercially in Japan, it is essential to set up the isolation distance required to prevent out-crossing between GM and conventional soybean in preparation for any future possibility of pollen transfer. The airborne soybean pollen was sampled using some Durham pollen samplers located in the range of 20 m from the field edge. In addition, the dispersal distance was assessed in a wind tunnel under constant air flow and then it was compared with the anticipated distances based on the pollen diameter. In the field, the maximum pollen density per day observed was 1.235 grains cm(-2) day(-1) at three observation points within 2.5 m from the field and inside the field the mean density did not reach the rate of 1 grain cm(-2 )day(-1) during 19 flowering days. The results of the wind tunnel experiment also showed that the plants had almost no airborne release of pollen and the dispersal distance was shorter than theoretical value due to clustered dispersal. This study showed little airborne pollen in and around the soybean field and the dispersal is restricted to a small area. Therefore, wind-mediated pollination appears to be negligible.

Pollen limitation and Allee effect related to population size and sex ratio in the endangered Ottelia acuminata (Hydrocharitaceae): implications for conservation and reintroduction.

PubMed

Xia, J; Lu, J; Wang, Z X; Hao, B B; Wang, H B; Liu, G H

2013-03-01

Small populations may suffer more severe pollen limitation and result in Allee effects. Sex ratio may also affect pollination and reproduction success in dioecious species, which is always overlooked when performing conservation and reintroduction tasks. In this study, we investigated whether and how population size and sex ratio affected pollen limitation and reproduction in the endangered Ottelia acuminata, a dioecious submerged species. We established experimental plots with increasing population size and male sex ratio. We observed insect visitation, estimated pollen limitation by hand-pollinations and counted fruit set and seed production per fruit. Fruit set and seed production decreased significantly in small populations due to pollinator scarcity and thus suffered more severe pollen limitation. Although frequently visited, female-biased larger populations also suffered severe pollen limitation due to few effective visits and insufficient pollen availability. Rising male ratio enhanced pollination service and hence reproduction. Unexpectedly, pollinator preferences did not cause reduced reproduction in male-biased populations because of high pollen availability. However, reproductive outputs showed more variability in severe male-biased populations. Our results revealed two component Allee effects in fruit set and seed production, mediated by pollen limitation in O. acuminata. Moreover, reproduction decreased significantly in larger female-biased populations, increasing the risk of an Allee effect. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

A Recombinant Fragment of Human Surfactant Protein D Suppresses Basophil Activation and T-Helper Type 2 and B-Cell Responses in Grass Pollen-induced Allergic Inflammation.

PubMed

Qaseem, Asif S; Singh, Iesha; Pathan, Ansar A; Layhadi, Janice A; Parkin, Rebecca; Alexandra, Fedina; Durham, Stephen R; Kishore, Uday; Shamji, Mohamed H

2017-12-15

Recombinant fragment of human surfactant protein D (rfhSP-D) has been shown to suppress house dust mite- and Aspergillus fumigatus-induced allergic inflammation in murine models. We sought to elucidate the effect of rfhSP-D on high-affinity IgE receptor- and CD23-mediated, grass pollen-induced allergic inflammatory responses. rfhSP-D, containing homotrimeric neck and lectin domains, was expressed in Escherichia coli BL21(λDE3)pLysS cells. Peripheral blood mononuclear cells and sera were obtained from individuals with grass pollen allergy (n = 27). The effect of rfhSP-D on basophil activation and histamine release was measured by flow cytometry. IgE-facilitated allergen binding and presentation were assessed by flow cytometry. T-helper cell type 2 (Th2) cytokines were measured in cell culture supernatants. The effect of rfhSP-D on IgE production by B cells when stimulated with CD40L, IL-4, and IL-21 was also determined. rfhSP-D bound to Phleum pratense in a dose- and calcium-dependent manner. Allergen-induced basophil responsiveness and histamine release were inhibited in the presence of rfhSP-D, as measured by CD63, CD203c (P = 0.0086, P = 0.04205), and intracellularly labeled diamine oxidase (P = 0.0003, P = 0.0148). The binding of allergen-IgE complexes to B cells was reduced by 51% (P = 0.002) in the presence of rfhSP-D. This decrease was concomitant with reduction in CD23 expression on B cells (P < 0.001). rfhSP-D suppressed allergen-driven CD27 - CD4 + CRTh2 + T-cell proliferation (P < 0.01), IL-4, and IL-5 levels (all P < 0.01). Moreover, rfhSP-D inhibited CD40L/IL-4- and IL-21-mediated IgE production (77.12%; P = 0.02) by B cells. For the first time, to our knowledge, we show that rfhSP-D inhibited allergen-induced basophil responses at a single-cell level and suppressed CD23-mediated facilitated allergen presentation and Th2 cytokine production. In addition, rfhSP-D inhibited IgE synthesis by B cells, which is also a novel observation.

Identifying Novel Regulators of Vacuolar Trafficking by Combining Fluorescence Imaging-Based Forward Genetic Screening and In Vitro Pollen Germination.

PubMed

Feng, Qiang-Nan; Zhang, Yan

2017-01-01

Subcellular targeting of vacuolar proteins depends on cellular machinery regulating vesicular trafficking. Plant-specific vacuolar trafficking routes have been reported. However, regulators mediating these processes are obscure. By combining a fluorescence imaging-based forward genetic approach and in vitro pollen germination system, we show an efficient protocol of identifying regulators of plant-specific vacuolar trafficking routes.

Cross-reactivity among non-specific lipid-transfer proteins from food and pollen allergenic sources.

PubMed

Morales, María; López-Matas, M Ángeles; Moya, Raquel; Carnés, Jerónimo

2014-12-15

Non-specific lipid-transfer proteins (nsLTPs) are a family of pan-allergens present in foods and pollen. However, sequence homology among them is limited. The objective of this study was to evaluate the IgE-mediated cross-reactivity between nsLTPs from different sources and evaluate the allergenic properties of LTPs from peach (Pru p 3) and pellitory (Par j 1/Par j 2), major fruit and pollen allergens. Both proteins were purified and characterised. Cross-reactivity studies among nsLTPs from different foods and pollens were performed by immunoblot inhibition using sera specific to peach or pellitory pollen. Cross-reactivity with Pru p 3 was observed in hazelnut, onion, corn, peanut and apple while in pollens, none of the extracts was inhibited with Par j 1/2. In conclusion, Pru p 3 did not inhibit LTPs from most fruits. Therefore, although Pru p 3 covers the largest number of epitopes, diagnosis with only this allergen may not detect all LTP sensitivities. Copyright © 2014 Elsevier Ltd. All rights reserved.

PiSCP1 and PiCDPK2 Localize to Peroxisomes and Are Involved in Pollen Tube Growth in Petunia Inflata

PubMed Central

Guo, Feng; Yoon, Gyeong Mee; McCubbin, Andrew G.

2013-01-01

Petunia inflata small CDPK-interacting protein 1 (PiSCP1) was identified as a pollen expressed PiCDPK1 interacting protein using the yeast two hybrid system and the interaction confirmed using pull-down and phosphorylation assays. PiSCP1 is pollen specific and shares amino acid homology with uncharacterized proteins from diverse species of higher plants, but no protein of known function. Expression of PiSCP1-GFP in vivo inhibited pollen tube growth and was shown to localize to peroxisomes in growing pollen tubes. As PiCDPK1 is plasma membrane localized, we investigated the localization of a second isoform, PiCDPK2, and show that it co-localizes to peroxisomes with PiSCP1 and that the two proteins interact in the yeast 2 hybrid interaction assay, suggesting that interaction with the latter CDPK isoform is likely the one of biological relevance. Both PiCDPK2 and PiSCP1 affect pollen tube growth, presumably by mediating peroxisome function, however how they do so is currently not clear. PMID:27137367

Less Pollen-Mediated Gene Flow for More Signatures of Glacial Lineages: Congruent Evidence from Balsam Fir cpDNA and mtDNA for Multiple Refugia in Eastern and Central North America

PubMed Central

Cinget, Benjamin; Gérardi, Sébastien; Beaulieu, Jean; Bousquet, Jean

2015-01-01

The phylogeographic structure and postglacial history of balsam fir (Abies balsamea), a transcontinental North American boreal conifer, was inferred using mitochondrial DNA (mtDNA) and chloroplast DNA (cpDNA) markers. Genetic structure among 107 populations (mtDNA data) and 75 populations (cpDNA data) was analyzed using Bayesian and genetic distance approaches. Population differentiation was high for mtDNA (dispersed by seeds only), but also for cpDNA (dispersed by seeds and pollen), indicating that pollen gene flow is more restricted in balsam fir than in other boreal conifers. Low cpDNA gene flow in balsam fir may relate to low pollen production due to the inherent biology of the species and populations being decimated by recurrent spruce budworm epidemics, and/or to low dispersal of pollen grains due to their peculiar structural properties. Accordingly, a phylogeographic structure was detected using both mtDNA and cpDNA markers and population structure analyses supported the existence of at least five genetically distinct glacial lineages in central and eastern North America. Four of these would originate from glacial refugia located south of the Laurentide ice sheet, while the last one would have persisted in the northern Labrador region. As expected due to reduced pollen-mediated gene flow, congruence between the geographic distribution of mtDNA and cpDNA lineages was higher than in other North American conifers. However, concordance was not complete, reflecting that restricted but nonetheless detectable cpDNA gene flow among glacial lineages occurred during the Holocene. As a result, new cpDNA and mtDNA genome combinations indicative of cytoplasmic genome capture were observed. PMID:25849816

High correlation of specific IgE sensitization between birch pollen, soy and apple allergens indicates pollen-food allergy syndrome among birch pollen allergic patients in northern China.

PubMed

Hao, Guo-Dong; Zheng, Yi-Wu; Wang, Zhi-Xiang; Kong, Xing-Ai; Song, Zhi-Jing; Lai, Xu-Xin; Spangfort, Michael D

2016-05-01

Birch pollen sensitization and associated pollen-food syndrome among Chinese allergic patients have not been investigated. Sera from 203 allergic patients from the northern part of China and collected during February to July 2014 were investigated. Specific immunoglobulin E (IgE) against birch pollen extract Bet v and major birch pollen allergen Bet v 1 were measured using the ADVIA Centaur. The presence of major apple allergen Mal d 1 and soy bean allergen Gly m 4 specific IgE was measured by ImmunoCAP 100. Among the 203 sera, 34 sera (16.7%) had specific IgE to Bet v and of these, 28 sera (82.4%) contained Bet v 1-specific IgE. Among the 28 sera with Bet v 1-specific IgE, 27 sera (96.4%) contained Mal d 1-specific IgE and 22 sera (78.6%) contained Gly m 4-specific IgE. Of the 34 Bet v-positive sera, 6 sera (17.6%) contained no specific IgE for Bet v 1, Mal d 1, or Gly m 4. Almost all Bet v-positive sera were donated during the birch pollen season. The prevalence of birch allergy among patients visiting health care during pollen season can be as high as 16.7% in Tangshan City. The majority of Chinese birch allergic patients are IgE-sensitized to the major birch pollen allergen Bet v 1 as well as to the major apple allergen Mal d 1 and soy bean allergen Gly m 4. A relatively high number of patients (17.6%) are IgE-sensitized to birch pollen allergen(s) other than Bet v 1. The high prevalence of specific IgE to Mal d 1 and Gly m 4 among Bet v 1-sensitized patients indicates that pollen-food allergy syndrome could be of clinical relevance in China.

Pollinator-mediated selection on flower color, flower scent and flower morphology of Hemerocallis: evidence from genotyping individual pollen grains on the stigma.

PubMed

Hirota, Shun K; Nitta, Kozue; Suyama, Yoshihisa; Kawakubo, Nobumitsu; Yasumoto, Akiko A; Yahara, Tetsukazu

2013-01-01

To trace the fate of individual pollen grains through pollination processes, we determined genotypes of single pollen grains deposited on Hemerocallis stigmas in an experimental mixed-species array. Hemerocallis fulva, pollinated by butterflies, has diurnal, reddish and unscented flowers, and H. citrina, pollinated by hawkmoths, has nocturnal, yellowish and sweet scent flowers. We observed pollinator visits to an experimental array of 24 H. fulva and 12 F2 hybrids between the two species (H. fulva and H. citrina) and collected stigmas after every trip bout of swallowtail butterflies or hawkmoths. We then measured selection by swallowtail butterflies or hawkmoths through male and female components of pollination success as determined by single pollen genotyping. As expected, swallowtail butterflies imposed selection on reddish color and weak scent: the number of outcross pollen grains acquired is a quadratic function of flower color with the maximum at reddish color, and the combined pollination success was maximal at weak scent (almost unrecognizable for human). This explains why H. fulva, with reddish flowers and no recognizable scent, is mainly pollinated by swallowtail butterflies. However, we found no evidence of hawkmoths-mediated selection on flower color or scent. Our findings do not support a hypothesis that yellow flower color and strong scent intensity, the distinctive floral characteristics of H. citrina, having evolved in adaptations to hawkmoths. We suggest that the key trait that triggers the evolution of nocturnal flowers is flowering time rather than flower color and scent.

Pollen tube access to the ovule is mediated by glycoprotein secretion on the obturator of apple (Malus × domestica, Borkh)

PubMed Central

Herrero, Maria

2017-01-01

Background and Aims Within the ovary, the obturator bridges the pathway of the pollen tube from the style to the ovule. Despite its widespread presence among flowering plants, its function has only been studied in a handful of species, and the molecules involved in pollen tube–obturator cross-talk have not been explored hitherto. This work evaluates the involvement of glucans and glycoproteins on pollen tube growth in the obturator of apple flowers (Malus × domestica). Methods Pollen tube kinetics were sequentially examined in the pistil and related to changes occurring on the obturator using histochemistry and inmunocytochemistry. To discriminate between changes in the obturator induced by pollen tubes from those developmentally regulated, both pollinated and unpollinated pistils were examined. Key Results Pollen tube growth rates were slow in the stigma, faster in the style and slow again in the ovary. The arrival of pollen tubes at the obturator was concomitant with the secretion of proteins, saccharides and glycoprotein epitopes belonging to extensins and arabinogalactan proteins (AGPs). While some of these secretions – extensins and AGPs labelled by JIM13 – were developmentally regulated, others – AGPs labelled by JIM8 – were elicited by the presence of pollen tubes. Following pollen tube passage, all these glycoproteins were depleted. Conclusions The results show a timely secretion of glycoproteins on the obturator surface concomitant with pollen tube arrival at this structure. The fact that their secretion is depleted following pollen tube passage strongly suggests their role in regulating pollen tube access to the ovule. Remarkably, both the regulation of the secretion of the different glycoproteins, as well as their association with the performance of pollen tubes exhibit similarities with those observed in the stigma, in line with their common developmental origin. PMID:28137704

Pollen tube access to the ovule is mediated by glycoprotein secretion on the obturator of apple (Malus × domestica, Borkh).

PubMed

Losada, Juan M; Herrero, Maria

2017-04-01

Within the ovary, the obturator bridges the pathway of the pollen tube from the style to the ovule. Despite its widespread presence among flowering plants, its function has only been studied in a handful of species, and the molecules involved in pollen tube-obturator cross-talk have not been explored hitherto. This work evaluates the involvement of glucans and glycoproteins on pollen tube growth in the obturator of apple flowers ( Malus × domestica) . Pollen tube kinetics were sequentially examined in the pistil and related to changes occurring on the obturator using histochemistry and inmunocytochemistry. To discriminate between changes in the obturator induced by pollen tubes from those developmentally regulated, both pollinated and unpollinated pistils were examined. Pollen tube growth rates were slow in the stigma, faster in the style and slow again in the ovary. The arrival of pollen tubes at the obturator was concomitant with the secretion of proteins, saccharides and glycoprotein epitopes belonging to extensins and arabinogalactan proteins (AGPs). While some of these secretions - extensins and AGPs labelled by JIM13 - were developmentally regulated, others - AGPs labelled by JIM8 - were elicited by the presence of pollen tubes. Following pollen tube passage, all these glycoproteins were depleted. The results show a timely secretion of glycoproteins on the obturator surface concomitant with pollen tube arrival at this structure. The fact that their secretion is depleted following pollen tube passage strongly suggests their role in regulating pollen tube access to the ovule. Remarkably, both the regulation of the secretion of the different glycoproteins, as well as their association with the performance of pollen tubes exhibit similarities with those observed in the stigma, in line with their common developmental origin. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Trichuris suis ova therapy for allergic rhinitis does not affect allergen-specific cytokine responses despite a parasite-specific cytokine response.

PubMed

Bourke, C D; Mutapi, F; Nausch, N; Photiou, D M F; Poulsen, L K; Kristensen, B; Arnved, J; Rønborg, S; Roepstorff, A; Thamsborg, S; Kapel, C; Melbye, M; Bager, P

2012-11-01

Parasitic helminths have been shown to reduce inflammation in most experimental models of allergic disease, and this effect is mediated via cytokine responses. However, in humans, the effects of controlled helminth infection on cytokine responses during allergy have not been studied. The aim was to investigate whether infection with the nematode parasite Trichuris suis alters systemic cytokine levels, cellular cytokine responses to parasite antigens and pollen allergens and/or the cytokine profile of allergic individuals. In a randomized double-blinded placebo-controlled clinical trial (UMIN trial registry, Registration no. R000001298, Trial ID UMIN000001070, URL: http://www.umin.ac.jp/map/english), adults with grass pollen-induced allergic rhinitis received three weekly doses of 2500 Trichuris suis ova (n = 45) or placebo (n = 44) over 6 months. IFN-γ, TNF-α, IL-4, IL-5, IL-10 and IL-13 were quantified via cytometric bead array in plasma. Cytokines, including active TGF-β, were also quantified in supernatants from peripheral blood mononuclear cells cultured with parasite antigens or pollen allergens before, during and after the grass pollen season for a sub-cohort of randomized participants (T. suis ova-treated, n = 12, Placebo-treated, n = 10). Helminth infection induced a Th2-polarized cytokine response comprising elevated plasma IL-5 and parasite-specific IL-4, IL-5 and IL-13, and a global shift in the profile of systemic cytokine responses. Infection also elicited high levels of the regulatory cytokine IL-10 in response to T. suis antigens. Despite increased production of T. suis-specific cytokines in T. suis ova-treated participants, allergen-specific cytokine responses during the grass pollen season and the global profile of PBMC cytokine responses were not affected by T. suis ova treatment. This study suggests that cytokines induced by Trichuris suis ova treatment do not alter allergic reactivity to pollen during the peak of allergic rhinitis symptoms. © 2012 Blackwell Publishing Ltd.

IgE and allergen-specific immunotherapy-induced IgG4 recognize similar epitopes of Bet v 1, the major allergen of birch pollen.

PubMed

Groh, N; von Loetzen, C S; Subbarayal, B; Möbs, C; Vogel, L; Hoffmann, A; Fötisch, K; Koutsouridou, A; Randow, S; Völker, E; Seutter von Loetzen, A; Rösch, P; Vieths, S; Pfützner, W; Bohle, B; Schiller, D

2017-05-01

Allergen-specific immunotherapy (AIT) with birch pollen generates Bet v 1-specific immunoglobulin (Ig)G 4 which blocks IgE-mediated hypersensitivity mechanisms. Whether IgG 4 specific for Bet v 1a competes with IgE for identical epitopes or whether novel epitope specificities of IgG 4 antibodies are developed is under debate. We sought to analyze the epitope specificities of IgE and IgG 4 antibodies from sera of patients who received AIT. 15 sera of patients (13/15 received AIT) with Bet v 1a-specific IgE and IgG 4 were analyzed. The structural arrangements of recombinant (r)Bet v 1a and rBet v 1a _11x , modified in five potential epitopes, were analyzed by circular dichroism and nuclear magnetic resonance spectroscopy. IgE binding to Bet v 1 was assessed by ELISA and mediator release assays. Competitive binding of monoclonal antibodies specific for Bet v 1a and serum IgE/IgG 4 to rBet v 1a and serum antibody binding to a non-allergenic Bet v 1-type model protein presenting an individual epitope for IgE was analyzed in ELISA and western blot. rBet v 1a _11x had a Bet v 1a - similar secondary and tertiary structure. Monomeric dispersion of rBet v 1a _11x was concentration and buffer-dependent. Up to 1500-fold increase in the EC 50 for IgE-mediated mediator release induced by rBet v 1a _11x was determined. The reduction of IgE and IgG 4 binding to rBet v 1a _11x was comparable in 67% (10/15) of sera. Bet v 1a-specific monoclonal antibodies inhibited binding of serum IgE and IgG 4 to 66.1% and 64.9%, respectively. Serum IgE and IgG 4 bound specifically to an individual epitope presented by our model protein in 33% (5/15) of sera. Patients receiving AIT develop Bet v 1a-specific IgG 4 which competes with IgE for partly identical or largely overlapping epitopes. The similarities of epitopes for IgE and IgG 4 might stimulate the development of epitope-specific diagnostics and therapeutics. © 2016 John Wiley & Sons Ltd.

High-throughput sequencing of small RNAs from pollen and silk and characterization of miRNAs as candidate factors involved in pollen-silk interactions in maize.

PubMed

Li, Xiao Ming; Sang, Ya Lin; Zhao, Xiang Yu; Zhang, Xian Sheng

2013-01-01

In angiosperms, successful pollen-pistil interactions are the prerequisite and guarantee of subsequent fertilization and seed production. Recent profile analyses have helped elucidate molecular mechanisms underlying these processes at both transcriptomic and proteomic levels, but the involvement of miRNAs in pollen-pistil interactions is still speculative. In this study, we sequenced four small RNA libraries derived from mature pollen, in vitro germinated pollen, mature silks, and pollinated silks of maize (Zea mays L.). We identified 161 known miRNAs belonging to 27 families and 82 novel miRNAs. Of these, 40 conserved and 16 novel miRNAs showed different expression levels between mature and germinated pollen, and 30 conserved and eight novel miRNAs were differentially expressed between mature and pollinated silks. As candidates for factors associated with pollen-silk (pistil) interactions, expression patterns of the two sets of differentially expressed miRNAs were confirmed by stem-loop real-time RT-PCR. Transcript levels of 22 predicted target genes were also validated using real-time RT-PCR; most of these exhibited expression patterns contrasting with those of their corresponding miRNAs. In addition, GO analysis of target genes of differentially expressed miRNAs revealed that functional categories related to auxin signal transduction and gene expression regulation were overrepresented. These results suggest that miRNA-mediated auxin signal transduction and transcriptional regulation have roles in pollen-silk interactions. The results of our study provide novel information for understanding miRNA regulatory roles in pollen-pistil interactions.

Pollen derived low molecular compounds enhance the human allergen specific immune response in vivo.

PubMed

Gilles-Stein, S; Beck, I; Chaker, A; Bas, M; McIntyre, M; Cifuentes, L; Petersen, A; Gutermuth, J; Schmidt-Weber, C; Behrendt, H; Traidl-Hoffmann, C

2016-10-01

Besides allergens, pollen release bioactive, low molecular weight compounds that modulate and stimulate allergic reactions. Clinical relevance of these substances has not been investigated to date. To elucidate the effect of a non-allergenic, low molecular weight factors from aqueous birch pollen extracts (Bet-APE < 3 kDa) on the human allergic immune response in vivo. Birch and grass pollen allergic individuals underwent skin prick testing with allergen alone, allergen plus Bet-APE < 3 kDa, or allergen plus pre-identified candidate substances from low molecular pollen fraction. Nasal allergen challenges were performed in non-atopic and pollen allergic individuals using a 3 day repeated threshold challenge battery. Subjects were either exposed to allergen alone or to allergen plus Bet-APE< 3 kDa. Local cytokine levels, nasal secretion weights, nasal congestion and symptom scores were determined. Skin prick test reactions to pollen elicited larger weals when allergens were tested together with the low molecular weight compounds from pollen. Similar results were obtained with candidate pollen-associated lipid mediators. In nasal lining fluids of allergic patients challenged with allergen plus Bet-APE < 3 kDa, IL-8 and IgE was significantly increased as compared to allergen-only challenged patients. These patients also produced increased amounts of total nasal secretion and reported more severe rhinorrhea than the allergen-only challenged group. Low molecular compounds from pollen enhance the allergen specific immune response in the skin and nose. They are therefore of potential clinical relevance in allergic patients. © 2016 John Wiley & Sons Ltd.

Paternity analysis of pollen-mediated gene flow for Fraxinus excelsior L. in a chronically fragmented landscape.

PubMed

Bacles, C F E; Ennos, R A

2008-10-01

Paternity analysis based on microsatellite marker genotyping was used to infer contemporary genetic connectivity by pollen of three population remnants of the wind-pollinated, wind-dispersed tree Fraxinus excelsior, in a deforested Scottish landscape. By deterministically accounting for genotyping error and comparing a range of assignment methods, individual-based paternity assignments were used to derive population-level estimates of gene flow. Pollen immigration into a 300 ha landscape represents between 43 and 68% of effective pollination, mostly depending on assignment method. Individual male reproductive success is unequal, with 31 of 48 trees fertilizing one seed or more, but only three trees fertilizing more than ten seeds. Spatial analysis suggests a fat-tailed pollen dispersal curve with 85% of detected pollination occurring within 100 m, and 15% spreading between 300 and 1900 m from the source. Identification of immigrating pollen sourced from two neighbouring remnants indicates further effective dispersal at 2900 m. Pollen exchange among remnants is driven by population size rather than geographic distance, with larger remnants acting predominantly as pollen donors, and smaller remnants as pollen recipients. Enhanced wind dispersal of pollen in a barren landscape ensures that the seed produced within the catchment includes genetic material from a wide geographic area. However, gene flow estimates based on analysis of non-dispersed seeds were shown to underestimate realized gene immigration into the remnants by a factor of two suggesting that predictive landscape conservation requires integrated estimates of post-recruitment gene flow occurring via both pollen and seed.

Differential Effects of Carbohydrates on Arabidopsis Pollen Germination.

PubMed

Hirsche, Jörg; García Fernández, José M; Stabentheiner, Edith; Großkinsky, Dominik K; Roitsch, Thomas

2017-04-01

Pollen germination as a crucial process in plant development strongly depends on the accessibility of carbon as energy source. Carbohydrates, however, function not only as a primary energy source, but also as important signaling components. In a comprehensive study, we analyzed various aspects of the impact of 32 different sugars on in vitro germination of Arabidopsis pollen comprising about 150 variations of individual sugars and combinations. Twenty-six structurally different mono-, di- and oligosaccharides, and sugar analogs were initially tested for their ability to support pollen germination. Whereas several di- and oligosaccharides supported pollen germination, hexoses such as glucose, fructose and mannose did not support and even considerably inhibited pollen germination when added to germination-supporting medium. Complementary experiments using glucose analogs with varying functional features, the hexokinase inhibitor mannoheptulose and the glucose-insensitive hexokinase-deficient Arabidopsis mutant gin2-1 suggested that mannose- and glucose-mediated inhibition of sucrose-supported pollen germination depends partially on hexokinase signaling. The results suggest that, in addition to their role as energy source, sugars act as signaling molecules differentially regulating the complex process of pollen germination depending on their structural properties. Thus, a sugar-dependent multilayer regulation of Arabidopsis pollen germination is supported, which makes this approach a valuable experimental system for future studies addressing sugar sensing and signaling. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Calreticulin is required for calcium homeostasis and proper pollen tube tip growth in Petunia.

PubMed

Suwińska, Anna; Wasąg, Piotr; Zakrzewski, Przemysław; Lenartowska, Marta; Lenartowski, Robert

2017-05-01

Calreticulin is involved in stabilization of the tip-focused Ca 2+ gradient and the actin cytoskeleton arrangement and function that is required for several key processes driving Petunia pollen tube tip growth. Although the precise mechanism is unclear, stabilization of a tip-focused calcium (Ca 2+ ) gradient seems to be critical for pollen germination and pollen tube growth. We hypothesize that calreticulin (CRT), a Ca 2+ -binding/buffering chaperone typically residing in the lumen of the endoplasmic reticulum (ER) of eukaryotic cells, is an excellent candidate to fulfill this role. We previously showed that in Petunia pollen tubes growing in vitro, CRT is translated on ER membrane-bound ribosomes that are abundant in the subapical zone of the tube, where CRT's Ca 2+ -buffering and chaperone activities might be particularly required. Here, we sought to determine the function of CRT using small interfering RNA (siRNA) to, for the first time in pollen tubes growing in vitro, knockdown expression of a gene. We demonstrate that siRNA-mediated post-transcriptional silencing of Petunia hybrida CRT gene (PhCRT) expression strongly impairs pollen tube growth, cytoplasmic zonation, actin cytoskeleton organization, and the tip-focused Ca 2+ gradient. Moreover, reduction of CRT alters the localization and disturbs the structure of the ER in abnormally elongating pollen tubes. Finally, cytoplasmic streaming is inhibited, and most of the pollen tubes rupture. Our data clearly show an interplay between CRT, Ca 2+ gradient, actin-dependent cytoplasmic streaming, organelle positioning, and vesicle trafficking during pollen tube elongation. Thus, we suggest that CRT functions in Petunia pollen tube growth by stabilizing Ca 2+ homeostasis and acting as a chaperone to assure quality control of glycoproteins passing through the ER.

Chemical modification of coating of Pinus halepensis pollen by ozone exposure.

PubMed

Naas, Oumsaad; Mendez, Maxence; Quijada, Melesio; Gosselin, Sylvie; Farah, Jinane; Choukri, Ali; Visez, Nicolas

2016-07-01

Pollen coating, located on the exine, includes an extractible lipid fraction. The modification of the pollen coating by air pollutants may have implications on the interactions of pollen with plant stigmas and human cells. Pinus halepensis pollen was exposed to ozone in vitro and the pollen coating was extracted with organic solvent and analyzed by GC-MS. Ozone has induced chemical changes in the coating as observed with an increase in dicarboxylic acids, short-chain fatty acids and aldehydes. 4-Hydroxybenzaldehyde was identified as the main reaction product and its formation was shown to occur both on native pollen and on defatted pollen. 4-Hydroxybenzaldehyde is very likely formed via the ozonolysis of acid coumaric-like monomers constitutive of the sporopollenin. Modification of pollen coating by air pollutants should be accounted for in further studies on effect of pollution on germination and on allergenicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbon-isotopic analysis of individual pollen grains from C 3 and C 4 grasses using a spooling-wire microcombustion interface

NASA Astrophysics Data System (ADS)

Nelson, David M.; Hu, Feng Sheng; Mikucki, Jill A.; Tian, Jian; Pearson, Ann

2007-08-01

Pollen grains from grasses using the C 3 and C 4 photosynthetic pathways have distinct ranges of δ 13C values that may be used to estimate their relative abundance in paleorecords. We evaluated a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer (SWiM-IRMS) for δ 13C analysis of individual grass-pollen grains. Pollen from four C 3 and four C 4 grass species was isolated through micromanipulation and analyzed as single grains suspended in water. A carbon yield greater than the 2 σ range of the carbon content of blanks containing only water was used to distinguish samples containing pollen ("pollen present") from those not containing pollen. This criterion resulted in the exclusion of ˜45% of the 946 samples applied to the wire. The average δ 13C values (±1 σ) of the remaining samples were -26.9‰ (±6.3‰) and -11.5‰ (±9.6‰) for C 3 grasses and C 4 grasses, respectively, after blank-correcting the δ 13C data. These results suggest that the SWiM-IRMS system can be used to distinguish C 3 from C 4 grass pollen. The high variability in measured δ 13C values is likely caused by a combination of factors. These include natural isotopic variability among individual pollen grains; the relatively poor precision that can be obtained when determining δ 13C values of such small samples; and the uncertainty in the magnitude, isotopic composition, and stability of the analytical blank. Nonetheless, high percentages of individual pollen grains were correctly classified as being of either C 3 or C 4 origin. On average, 90% (range = 78-100%) of pollen grains from C 3 grasses had δ 13C values more negative than the cutoff threshold of -19.2‰; while 84% (range = 77-90%) of pollen grains from C 4 grasses had δ 13C values more positive than -19.2‰. Compared with analysis using an elemental analyzer interfaced with an IRMS (EA-IRMS), the number of pollen grains required for δ 13C-based evaluation of C 3/C 4 grass composition is many times lower with the SWiM-IRMS. Additionally, δ 13C data from the SWiM-IRMS does not need to be incorporated into a mixing model to derive estimates of the abundance of C 3 and C 4 grass pollen. Carbon-isotopic analysis of individual grass-pollen grains using the SWiM-IRMS system may help improve our understanding of the evolutionary and ecological significance of grass taxa in the paleorecord.

Changes in Sensitization Rate to Weed Allergens in Children with Increased Weeds Pollen Counts in Seoul Metropolitan Area

PubMed Central

Kim, Joo-Hwa; Lee, Ha-Baik; Kim, Seong-Won; Kang, Im-Joo; Kook, Myung-Hee; Kim, Bong-Seong; Park, Kang-Seo; Baek, Hey-Sung; Kim, Kyu-Rang; Choi, Young-Jean

2012-01-01

The prevalence of allergic diseases in children has increased for several decades. We evaluated the correlation between pollen count of weeds and their sensitization rate in Seoul, 1997-2009. Airborne particles carrying allergens were collected daily from 3 stations around Seoul. Skin prick tests to pollen were performed on children with allergic diseases. Ragweed pollen gradually increased between 1999 and 2005, decreased after 2005 and plateaued until 2009 (peak counts, 67 in 2003, 145 in 2005 and 83 grains/m3/day in 2007). Japanese hop pollen increased between 2002 and 2009 (peak counts, 212 in 2006 and 492 grains/m3/day in 2009). Sensitization rates to weed pollen, especially ragweed and Japanese hop in children with allergic diseases, increased annually (ragweed, 2.2% in 2000 and 2.8% in 2002; Japanese hop, 1.4% in 2000 and 1.9% in 2002). The age for sensitization to pollen gradually became younger since 2000 (4 to 6 yr of age, 3.5% in 1997 and 6.2% in 2009; 7 to 9 yr of age, 4.2% in 1997 and 6.4% in 2009). In conclusion, sensitization rates for weed pollens increase in Korean children given increasing pollen counts of ragweed and Japanese hop. PMID:22468096

Changes in sensitization rate to weed allergens in children with increased weeds pollen counts in Seoul metropolitan area.

PubMed

Kim, Joo-Hwa; Oh, Jae-Won; Lee, Ha-Baik; Kim, Seong-Won; Kang, Im-Joo; Kook, Myung-Hee; Kim, Bong-Seong; Park, Kang-Seo; Baek, Hey-Sung; Kim, Kyu-Rang; Choi, Young-Jean

2012-04-01

The prevalence of allergic diseases in children has increased for several decades. We evaluated the correlation between pollen count of weeds and their sensitization rate in Seoul, 1997-2009. Airborne particles carrying allergens were collected daily from 3 stations around Seoul. Skin prick tests to pollen were performed on children with allergic diseases. Ragweed pollen gradually increased between 1999 and 2005, decreased after 2005 and plateaued until 2009 (peak counts, 67 in 2003, 145 in 2005 and 83 grains/m(3)/day in 2007). Japanese hop pollen increased between 2002 and 2009 (peak counts, 212 in 2006 and 492 grains/m(3)/day in 2009). Sensitization rates to weed pollen, especially ragweed and Japanese hop in children with allergic diseases, increased annually (ragweed, 2.2% in 2000 and 2.8% in 2002; Japanese hop, 1.4% in 2000 and 1.9% in 2002). The age for sensitization to pollen gradually became younger since 2000 (4 to 6 yr of age, 3.5% in 1997 and 6.2% in 2009; 7 to 9 yr of age, 4.2% in 1997 and 6.4% in 2009). In conclusion, sensitization rates for weed pollens increase in Korean children given increasing pollen counts of ragweed and Japanese hop.

A prognostic pollen emissions model for climate models (PECM1.0)

NASA Astrophysics Data System (ADS)

Wozniak, Matthew C.; Steiner, Allison L.

2017-11-01

We develop a prognostic model called Pollen Emissions for Climate Models (PECM) for use within regional and global climate models to simulate pollen counts over the seasonal cycle based on geography, vegetation type, and meteorological parameters. Using modern surface pollen count data, empirical relationships between prior-year annual average temperature and pollen season start dates and end dates are developed for deciduous broadleaf trees (Acer, Alnus, Betula, Fraxinus, Morus, Platanus, Populus, Quercus, Ulmus), evergreen needleleaf trees (Cupressaceae, Pinaceae), grasses (Poaceae; C3, C4), and ragweed (Ambrosia). This regression model explains as much as 57 % of the variance in pollen phenological dates, and it is used to create a climate-flexible phenology that can be used to study the response of wind-driven pollen emissions to climate change. The emissions model is evaluated in the Regional Climate Model version 4 (RegCM4) over the continental United States by prescribing an emission potential from PECM and transporting pollen as aerosol tracers. We evaluate two different pollen emissions scenarios in the model using (1) a taxa-specific land cover database, phenology, and emission potential, and (2) a plant functional type (PFT) land cover, phenology, and emission potential. The simulated surface pollen concentrations for both simulations are evaluated against observed surface pollen counts in five climatic subregions. Given prescribed pollen emissions, the RegCM4 simulates observed concentrations within an order of magnitude, although the performance of the simulations in any subregion is strongly related to the land cover representation and the number of observation sites used to create the empirical phenological relationship. The taxa-based model provides a better representation of the phenology of tree-based pollen counts than the PFT-based model; however, we note that the PFT-based version provides a useful and climate-flexible emissions model for the general representation of the pollen phenology over the United States.

Identification of Cha o 3 homolog Cry j 4 from Cryptomeria japonica (Japanese cedar) pollen: Limitation of the present Japanese cedar-specific ASIT.

PubMed

Osada, Toshihiro; Tanaka, Yuki; Yamada, Akira; Sasaki, Eiji; Utsugi, Teruhiro

2018-03-07

About one-third of the Japanese population suffers from Japanese cedar pollinosis, which is frequently accompanied by Japanese cypress pollinosis. Recently, a novel major Japanese cypress pollen allergen, Cha o 3, was discovered. However, whether a Cha o 3 homolog is present in Japanese cedar pollen remains to be determined. Western blot analysis was performed using Cha o 3-specific antiserum. In addition, cloning of the gene encoding Cry j 4 was conducted using total cDNA from the male flower of Japanese cedar trees. Allergen potency and cross-reactivity were investigated using a T-cell proliferation assay, basophil activation test, and ImmunoCAP inhibition assay. A low amount of Cha o 3 homolog protein was detected in Japanese cedar pollen extract. The deduced amino acid sequence of Cry j 4 showed 84% identity to that of Cha o 3. Cross-reactivity between Cry j 4 and Cha o 3 was observed at the T cell and IgE levels. Cry j 4 was discovered as a counterpart allergen of Cha o 3 in Japanese cedar pollen, with a relationship similar to that between Cry j 1-Cha o 1 and Cry j 2-Cha o 2. Our findings also suggest that allergen-specific immunotherapy (ASIT) using Japanese cedar pollen extract does not induce adequate immune tolerance to Cha o 3 due to the low amount of Cry j 4 in Japanese cedar pollen. Therefore, ASIT using Cha o 3 or cypress pollen extract coupled with Japanese cedar pollen extract is required in order to optimally control allergy symptoms during Japanese cypress pollen season. Copyright © 2018 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

Plastidic phosphoglucomutase and ADP-glucose pyrophosphorylase mutants impair starch synthesis in rice pollen grains and cause male sterility

PubMed Central

Lee, Sang-Kyu; Eom, Joon-Seob; Hwang, Seon-Kap; Shin, Dongjin; An, Gynheung; Okita, Thomas W.; Jeon, Jong-Seong

2016-01-01

To elucidate the starch synthesis pathway and the role of this reserve in rice pollen, we characterized mutations in the plastidic phosphoglucomutase, OspPGM, and the plastidic large subunit of ADP-glucose (ADP-Glc) pyrophosphorylase, OsAGPL4. Both genes were up-regulated in maturing pollen, a stage when starch begins to accumulate. Progeny analysis of self-pollinated heterozygous lines carrying the OspPGM mutant alleles, osppgm-1 and osppgm-2, or the OsAGPL4 mutant allele, osagpl4-1, as well as reciprocal crosses between the wild type (WT) and heterozygotes revealed that loss of OspPGM or OsAGPL4 caused male sterility, with the former condition rescued by the introduction of the WT OspPGM gene. While iodine staining and transmission electron microscopy analyses of pollen grains from homozygous osppgm-1 lines produced by anther culture confirmed the starch null phenotype, pollen from homozygous osagpl4 mutant lines, osagpl4-2 and osagpl4-3, generated by the CRISPR/Cas system, accumulated small amounts of starch which were sufficient to produce viable seed. Such osagpl4 mutant pollen, however, was unable to compete against WT pollen successfully, validating the important role of this reserve in fertilization. Our results demonstrate that starch is mainly polymerized from ADP-Glc synthesized from plastidic hexose phosphates in rice pollen and that starch is an essential requirement for successful fertilization in rice. PMID:27588462

Pollen-mediated gene flow from transgenic cotton under greenhouse conditions is dependent on different pollinators

PubMed Central

Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Li, Zhen; Shelton, Anthony M.; Luo, Junyu; Cui, Jinjie; Zhang, Qingwen; Liu, Xiaoxia

2015-01-01

With the large-scale release of genetically modified (GM) crops, there are ecological concerns on transgene movement from GM crops to non-GM counterparts and wild relatives. In this research, we conducted greenhouse experiments to measure pollen-mediated gene flow (PGF) in the absence and presence of pollinators (Bombus ignitus, Apis mellifera and Pieris rapae) in one GM cotton (resistant to the insect Helicoverpa armigera and the herbicide glyphosate) and two non-GM lines (Shiyuan321 and Hai7124) during 2012 and 2013. Our results revealed that: (1) PGF varied depending on the pollinator species, and was highest with B. ignitus (10.83%) and lowest with P. rapae (2.71%); (2) PGF with B. ignitus depended on the distance between GM and non-GM cottons; (3) total PGF to Shiyuan321 (8.61%) was higher than to Hai7124 (4.10%). To confirm gene flow, we tested hybrids carrying transgenes for their resistance to glyphosate and H. armigera, and most hybrids showed strong resistance to the herbicide and insect. Our research confirmed that PGF depended on pollinator species, distance between plants and the receptor plant. PMID:26525573

Effects of fluoride on pollen germination, pollen tube growth, and fruit development in tomato and cucumber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sulzbach, C.W.; Pack, M.R.

Tomato and cucumber pollen germination in vitro was significantly inhibited at 10.5 and 2.6 mM NaF, respectively, or higher, in media containing 1.25 mM Ca. Germination was not inhibited provided the Ca was at least chemically equivalent to the F in the media. Long-term, continuous HF fumigations of tomato plants at 7.9 and 13.0 ..mu..g F/m/sup 3/ reduced pollen germination in vitro when the plants were grown with low Ca (1 mM) nutrient solution. No reduction was found at 13.0 ..mu..g F/m/sup 3/ when tomato plants were grown with 4 mM Ca. Regardless of Ca nutrition, HF fumigations of cucumbermore » plants at 10.2 ..mu..g F/m/sup 3/ or less did not inhibit pollen germination. Fluorescent staining of pistils from manually pollinated tomato flowers showed reductions in the number of pollen grains retained on the stigma, pollen germination, and pollen tubes reaching ovules when the maternal parent plants were grown in HF treatments averaging as low as 4.2 ..mu..g F/m/sup 3/. Similar effects were found when pollen parents grown with 1 mM Ca were subjected to 7.9 ..mu..g F/m/sup 3/, but not when pollen parents grown with 5 mM Ca were subjected to 4.4 ..mu..g F/m/sup 3/. Early tomato fruit and seed development were inhibited by treatments similar to those that caused the pollen responses. 11 references, 1 figure, 5 tables.« less

Storage and Viability Assessment of Date Palm Pollen.

PubMed

Maryam; Jaskani, Muhammad J; Naqvi, Summar A

2017-01-01

Pollen storage and viability are very important for pollination, breeding, biodiversity, biotechnology, conservation, and other biological and non-biological studies of the date palm. Optimizing procedures and duration of storage are important for effective and long-term date palm pollen storage and viability. Here we describe pollen storage methods, such as room temperature (25-30 °C), refrigeration (4 °C), storage at 4 °C in desiccators, deep freezer (-20 °C), and cryopreservation (-196 °C). Based on pollen viability by staining and in vitro germination methods, cryopreservation is the best method for long-term storage without any significant effect on pollen viability (75-84%); however, the percentage of pollen viability depends on the storage period.

Pollinator-Mediated Selection on Flower Color, Flower Scent and Flower Morphology of Hemerocallis: Evidence from Genotyping Individual Pollen Grains On the Stigma

PubMed Central

Hirota, Shun K.; Nitta, Kozue; Suyama, Yoshihisa; Kawakubo, Nobumitsu; Yasumoto, Akiko A.; Yahara, Tetsukazu

2013-01-01

To trace the fate of individual pollen grains through pollination processes, we determined genotypes of single pollen grains deposited on Hemerocallis stigmas in an experimental mixed-species array. Hemerocallis fulva, pollinated by butterflies, has diurnal, reddish and unscented flowers, and H. citrina, pollinated by hawkmoths, has nocturnal, yellowish and sweet scent flowers. We observed pollinator visits to an experimental array of 24 H. fulva and 12 F2 hybrids between the two species (H. fulva and H. citrina) and collected stigmas after every trip bout of swallowtail butterflies or hawkmoths. We then measured selection by swallowtail butterflies or hawkmoths through male and female components of pollination success as determined by single pollen genotyping. As expected, swallowtail butterflies imposed selection on reddish color and weak scent: the number of outcross pollen grains acquired is a quadratic function of flower color with the maximum at reddish color, and the combined pollination success was maximal at weak scent (almost unrecognizable for human). This explains why H. fulva, with reddish flowers and no recognizable scent, is mainly pollinated by swallowtail butterflies. However, we found no evidence of hawkmoths-mediated selection on flower color or scent. Our findings do not support a hypothesis that yellow flower color and strong scent intensity, the distinctive floral characteristics of H. citrina, having evolved in adaptations to hawkmoths. We suggest that the key trait that triggers the evolution of nocturnal flowers is flowering time rather than flower color and scent. PMID:24376890

Transgene autoexcision in switchgrass pollen mediated by the Bxb1 recombinase

PubMed Central

2014-01-01

Background Switchgrass (Panicum virgatum L.) has a great potential as a platform for the production of biobased plastics, chemicals and energy mainly because of its high biomass yield on marginal land and low agricultural inputs. During the last decade, there has been increased interest in the genetic improvement of this crop through transgenic approaches. Since switchgrass, like most perennial grasses, is exclusively cross pollinating and poorly domesticated, preventing the dispersal of transgenic pollen into the environment is a critical requisite for the commercial deployment of this important biomass crop. In this study, the feasibility of controlling pollen-mediated gene flow in transgenic switchgrass using the large serine site-specific recombinase Bxb1 has been investigated. Results A novel approach utilizing co-transformation of two separate vectors was used to test the functionality of the Bxb1/att recombination system in switchgrass. In addition, two promoters with high pollen-specific activity were identified and thoroughly characterized prior to their introduction into a test vector explicitly designed for both autoexcision and quantitative analyses of recombination events. Our strategy for developmentally programmed precise excision of the recombinase and marker genes in switchgrass pollen resulted in the generation of transgene-excised progeny. The autoexcision efficiencies were in the range of 22-42% depending on the transformation event and assay used. Conclusion The results presented here mark an important milestone towards the establishment of a reliable biocontainment system for switchgrass which will facilitate the development of this crop as a biorefinery feedstock through advanced biotechnological approaches. PMID:25148894

Combination of reversible male sterility and doubled haploid production by targeted inactivation of cytoplasmic glutamine synthetase in developing anthers and pollen.

PubMed

Ribarits, Alexandra; Mamun, A N K; Li, Shipeng; Resch, Tatiana; Fiers, Martijn; Heberle-Bors, Erwin; Liu, Chun-Ming; Touraev, Alisher

2007-07-01

Reversible male sterility and doubled haploid plant production are two valuable technologies in F(1)-hybrid breeding. F(1)-hybrids combine uniformity with high yield and improved agronomic traits, and provide self-acting intellectual property protection. We have developed an F(1)-hybrid seed technology based on the metabolic engineering of glutamine in developing tobacco anthers and pollen. Cytosolic glutamine synthetase (GS1) was inactivated in tobacco by introducing mutated tobacco GS genes fused to the tapetum-specific TA29 and microspore-specific NTM19 promoters. Pollen in primary transformants aborted close to the first pollen mitosis, resulting in male sterility. A non-segregating population of homozygous doubled haploid male-sterile plants was generated through microspore embryogenesis. Fertility restoration was achieved by spraying plants with glutamine, or by pollination with pollen matured in vitro in glutamine-containing medium. The combination of reversible male sterility with doubled haploid production results in an innovative environmentally friendly breeding technology. Tapetum-mediated sporophytic male sterility is of use in foliage crops, whereas microspore-specific gametophytic male sterility can be applied to any field crop. Both types of sterility preclude the release of transgenic pollen into the environment.

POLLINATOR-MEDIATED COMPETITION, REPRODUCTIVE CHARACTER DISPLACEMENT, AND THE EVOLUTION OF SELFING IN ARENARIA UNIFLORA (CARYOPHYLLACEAE).

PubMed

Fishman, Lila; Wyatt, Robert

1999-12-01

Ecological factors that reduce the effectiveness of cross-pollination are likely to play a role in the frequent evolution of routine self-fertilization in flowering plants. However, we lack empirical evidence linking the reproductive assurance value of selfing in poor pollination environments to evolutionary shifts in mating system. Here, we investigated the adaptive significance of prior selfing in the polymorphic annual plant Arenaria uniflora (Caryophyllaceae), in which selfer populations occur only in areas of range overlap with congener A. glabra. To examine the hypothesis that secondary contact between the two species contributed to the evolution and maintenance of selfing, we used field competition experiments and controlled hand-pollinations to measure the female fitness consequences of pollinator-mediated interspecific interactions. Uniformly high fruit set by selfers in the naturally pollinated field arrays confirmed the reproductive assurance value of selfing, whereas substantial reductions in outcrosser fruit set (15%) and total seed production (20-35%) in the presence of A. glabra demonstrated that pollinator-mediated interactions can provide strong selection for self-pollination. Heterospecific pollen transfer, rather than competition for pollinator service, appears to be the primary mechanism of pollinator-mediated competition in Arenaria. Premating barriers to hybridization between outcrossers and A. glabra are extremely weak. The production of a few inviable hybrid seeds after heterospecific pollination and intermediate seed set after mixed pollinations indicates that A. glabra pollen can usurp A. uniflora ovules. Thus, any visit to A. uniflora by shared pollinators carries a potential female fitness cost. Moreover, patterns of fruit set and seed set in the competition arrays relative to controls were consistent with the receipt of mixed pollen loads, rather than a lack of pollinator visits. Competition through pollen transfer favors preemptive self-pollination and may be responsible for the evolution of a highly reduced floral morphology in A. uniflora selfers as well as their current geographical distribution. © 1999 The Society for the Study of Evolution.

Prevalence of occupational allergy to bell pepper pollen in greenhouses in the Netherlands.

PubMed

Groenewoud, G C M; de Jong, N W; van Oorschot-van Nes, A J; Vermeulen, A M; van Toorenenbergen, A W; Mulder, P G H; Burdorf, A; de Groot, H; van Wijk, R Gerth

2002-03-01

An increasing number of allergic complaints appear to have occurred among bell pepper greenhouse employees. The aim of this study was to estimate the prevalence of work-related allergic symptoms and the prevalence of sensitization to specific occupational allergens and its determinants. We studied 472 employees who were invited to answer an extensive questionnaire and to be tested on location with inhalant allergens and home-made extracts of the bell pepper plant. In addition, peak expiratory flow monitoring and RASTs were performed. Work-related symptoms were reported in 53.8% of all cases. Sensitization to the bell pepper plant was found in 35.4%. Positive reactions to leaf, stem and/or juice, however, were associated in nearly 90% with sensitization to pollen, which appeared to be most important allergen of the plant. Sensitization to the bell pepper plant and inhalant atopy were considered the most important risk factors for the occurrence of work-related symptoms of the upper airways (PRR 2.63, CI 2.11-3.25 and PRR 2.25, CI 1.82-2.79) as well as of the lower airways (PRR 4.08, CI 2.38-7.00 and PRR 3.16, CI 1.87-5.33). There is a surprisingly high prevalence of work-related respiratory symptoms (53.8%) in bell pepper horticulture. In two-thirds of the employees, symptoms at work were associated with an IgE-mediated allergy due to the high and chronic exposure to bell pepper pollen. Complaints at work without specific sensitization to bell pepper pollen can be caused by non-specific hyper-reactivity or atopy to other occupational allergens. The extent of this occupational allergy has important consequences for the health care of this large, still growing occupational group.

Evolutionary origins of pectin methylesterase genes associated with novel aspects of angiosperm pollen tube walls.

PubMed

Wallace, Simon; Williams, Joseph H

2017-06-03

The early evolution of angiosperms was marked by a number of innovations of the reproductive cycle including an accelerated fertilization process involving faster transport of sperm to the egg via a pollen tube. Fast pollen tube growth rates in angiosperms are accompanied by a hard shank-soft tip pollen tube morphology. A critical actor in that morphology is the wall-embedded enzyme pectin methylesterase (PME), which in type II PMEs is accompanied by a co-transcribed inhibitor, PMEI. PMEs convert the esterified pectic tip wall to a stiffer state in the subapical flank by pectin de-esterification. It is hypothesized that rapid and precise targeting of PME activity was gained with the origin of type II genes, which are derived and have only expanded since the origin of vascular plants. Pollen-active PMEs have yet to be reported in early-divergent angiosperms or gymnosperms. Gene expression studies in Nymphaea odorata found transcripts from four type II VGD1-like and 16 type I AtPPME1-like homologs that were more abundant in pollen and pollen tubes than in vegetative tissues. The near full-length coding sequence of one type II PME (NoPMEII-1) included at least one PMEI domain. The identification of possible VGD1 homologs in an early-diverging angiosperm suggests that the refined control of PMEs that mediate de-esterification of pectins near pollen tube tips is a conserved feature across angiosperms. The recruitment of type II PMEs into a pollen tube elongation role in angiosperms may represent a key evolutionary step in the development of faster growing pollen tubes. Copyright © 2017 Elsevier Inc. All rights reserved.

A pollen-specific novel calmodulin-binding protein with tetratricopeptide repeats

NASA Technical Reports Server (NTRS)

Safadi, F.; Reddy, V. S.; Reddy, A. S.

2000-01-01

Calcium is essential for pollen germination and pollen tube growth. A large body of information has established a link between elevation of cytosolic Ca(2+) at the pollen tube tip and its growth. Since the action of Ca(2+) is primarily mediated by Ca(2+)-binding proteins such as calmodulin (CaM), identification of CaM-binding proteins in pollen should provide insights into the mechanisms by which Ca(2+) regulates pollen germination and tube growth. In this study, a CaM-binding protein from maize pollen (maize pollen calmodulin-binding protein, MPCBP) was isolated in a protein-protein interaction-based screening using (35)S-labeled CaM as a probe. MPCBP has a molecular mass of about 72 kDa and contains three tetratricopeptide repeats (TPR) suggesting that it is a member of the TPR family of proteins. MPCBP protein shares a high sequence identity with two hypothetical TPR-containing proteins from Arabidopsis. Using gel overlay assays and CaM-Sepharose binding, we show that the bacterially expressed MPCBP binds to bovine CaM and three CaM isoforms from Arabidopsis in a Ca(2+)-dependent manner. To map the CaM-binding domain several truncated versions of the MPCBP were expressed in bacteria and tested for their ability to bind CaM. Based on these studies, the CaM-binding domain was mapped to an 18-amino acid stretch between the first and second TPR regions. Gel and fluorescence shift assays performed with CaM and a CaM-binding synthetic peptide further confirmed MPCBP binding to CaM. Western, Northern, and reverse transcriptase-polymerase chain reaction analysis have shown that MPCBP expression is specific to pollen. MPCBP was detected in both soluble and microsomal proteins. Immunoblots showed the presence of MPCBP in mature and germinating pollen. Pollen-specific expression of MPCBP, its CaM-binding properties, and the presence of TPR motifs suggest a role for this protein in Ca(2+)-regulated events during pollen germination and growth.

Small RNA Sequencing Reveals Differential miRNA Expression in the Early Development of Broccoli (Brassica oleracea var. italica) Pollen

PubMed Central

Li, Hui; Wang, Yu; Wu, Mei; Li, Lihong; Jin, Chuan; Zhang, Qingli; Chen, Chengbin; Song, Wenqin; Wang, Chunguo

2017-01-01

Pollen development is an important and complex biological process in the sexual reproduction of flowering plants. Although the cytological characteristics of pollen development are well defined, the regulation of its early stages remains largely unknown. In the present study, miRNAs were explored in the early development of broccoli (Brassica oleracea var. italica) pollen. A total of 333 known miRNAs that originated from 235 miRNA families were detected. Fifty-five novel miRNA candidates were identified. Sixty of the 333 known miRNAs and 49 of the 55 predicted novel miRNAs exhibited significantly differential expression profiling in the three distinct developmental stages of broccoli pollen. Among these differentially expressed miRNAs, miRNAs that would be involved in the developmental phase transition from uninucleate microspores to binucleate pollen grains or from binucleate to trinucleate pollen grains were identified. miRNAs that showed significantly enriched expression in a specific early stage of broccoli pollen development were also observed. In addition, 552 targets for 127 known miRNAs and 69 targets for 40 predicted novel miRNAs were bioinformatically identified. Functional annotation and GO (Gene Ontology) analysis indicated that the putative miRNA targets showed significant enrichment in GO terms that were related to plant organ formation and morphogenesis. Some of enriched GO terms were detected for the targets directly involved in plant male reproduction development. These findings provided new insights into the functions of miRNA-mediated regulatory networks in broccoli pollen development. PMID:28392797

Small RNA Sequencing Reveals Differential miRNA Expression in the Early Development of Broccoli (Brassica oleracea var. italica) Pollen.

PubMed

Li, Hui; Wang, Yu; Wu, Mei; Li, Lihong; Jin, Chuan; Zhang, Qingli; Chen, Chengbin; Song, Wenqin; Wang, Chunguo

2017-01-01

Pollen development is an important and complex biological process in the sexual reproduction of flowering plants. Although the cytological characteristics of pollen development are well defined, the regulation of its early stages remains largely unknown. In the present study, miRNAs were explored in the early development of broccoli ( Brassica oleracea var. italica ) pollen. A total of 333 known miRNAs that originated from 235 miRNA families were detected. Fifty-five novel miRNA candidates were identified. Sixty of the 333 known miRNAs and 49 of the 55 predicted novel miRNAs exhibited significantly differential expression profiling in the three distinct developmental stages of broccoli pollen. Among these differentially expressed miRNAs, miRNAs that would be involved in the developmental phase transition from uninucleate microspores to binucleate pollen grains or from binucleate to trinucleate pollen grains were identified. miRNAs that showed significantly enriched expression in a specific early stage of broccoli pollen development were also observed. In addition, 552 targets for 127 known miRNAs and 69 targets for 40 predicted novel miRNAs were bioinformatically identified. Functional annotation and GO (Gene Ontology) analysis indicated that the putative miRNA targets showed significant enrichment in GO terms that were related to plant organ formation and morphogenesis. Some of enriched GO terms were detected for the targets directly involved in plant male reproduction development. These findings provided new insights into the functions of miRNA-mediated regulatory networks in broccoli pollen development.

Sialylated Fetuin-A as a candidate predictive biomarker for successful grass pollen allergen immunotherapy.

PubMed

Caillot, Noémie; Bouley, Julien; Jain, Karine; Mariano, Sandrine; Luce, Sonia; Horiot, Stéphane; Airouche, Sabi; Beuraud, Chloé; Beauvallet, Christian; Devillier, Philippe; Chollet-Martin, Sylvie; Kellenberger, Christine; Mascarell, Laurent; Chabre, Henri; Batard, Thierry; Nony, Emmanuel; Lombardi, Vincent; Baron-Bodo, Véronique; Moingeon, Philippe

2017-09-01

Eligibility to immunotherapy is based on the determination of IgE reactivity to a specific allergen by means of skin prick or in vitro testing. Biomarkers predicting the likelihood of clinical improvement during immunotherapy would significantly improve patient selection. Proteins were differentially assessed by using 2-dimensional differential gel electrophoresis and label-free mass spectrometry in pretreatment sera obtained from clinical responders and nonresponders within a cohort of 82 patients with grass pollen allergy receiving sublingual immunotherapy or placebo. Functional studies of Fetuin-A (FetA) were conducted by using gene silencing in a mouse asthma model, human dendritic cell in vitro stimulation assays, and surface plasmon resonance. Analysis by using quantitative proteomics of pretreatment sera from patients with grass pollen allergy reveals that high levels of O-glycosylated sialylated FetA isoforms are found in patients exhibiting a strong decrease in rhinoconjunctivitis symptoms after sublingual immunotherapy. Although FetA is involved in numerous inflammatory conditions, its potential role in allergy is unknown. In vivo silencing of the FETUA gene in BALB/c mice results in a dramatic upregulation of airway hyperresponsiveness, lung resistance, and T H 2 responses after allergic sensitization to ovalbumin. Both sialylated and nonsialytated FetA bind to LPS, but only the former synergizes with LPS and grass pollen or mite allergens to enhance the Toll-like receptor 4-mediated proallergic properties of human dendritic cells. As a reflection of the patient's inflammatory status, pretreatment levels of sialylated FetA in the blood are indicative of the likelihood of clinical responses during grass pollen immunotherapy. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS) gene expression patterns

PubMed Central

2011-01-01

Background A number of innovations underlie the origin of rapid reproductive cycles in angiosperms. A critical early step involved the modification of an ancestrally short and slow-growing pollen tube for faster and longer distance transport of sperm to egg. Associated with this shift are the predominantly callose (1,3-β-glucan) walls and septae (callose plugs) of angiosperm pollen tubes. Callose synthesis is mediated by callose synthase (CalS). Of 12 CalS gene family members in Arabidopsis, only one (CalS5) has been directly linked to pollen tube callose. CalS5 orthologues are present in several monocot and eudicot genomes, but little is known about the evolutionary origin of CalS5 or what its ancestral function may have been. Results We investigated expression of CalS in pollen and pollen tubes of selected non-flowering seed plants (gymnosperms) and angiosperms within lineages that diverged below the monocot/eudicot node. First, we determined the nearly full length coding sequence of a CalS5 orthologue from Cabomba caroliniana (CcCalS5) (Nymphaeales). Semi-quantitative RT-PCR demonstrated low CcCalS5 expression within several vegetative tissues, but strong expression in mature pollen. CalS transcripts were detected in pollen tubes of several species within Nymphaeales and Austrobaileyales, and comparative analyses with a phylogenetically diverse group of sequenced genomes indicated homology to CalS5. We also report in silico evidence of a putative CalS5 orthologue from Amborella. Among gymnosperms, CalS5 transcripts were recovered from germinating pollen of Gnetum and Ginkgo, but a novel CalS paralog was instead amplified from germinating pollen of Pinus taeda. Conclusion The finding that CalS5 is the predominant callose synthase in pollen tubes of both early-diverging and model system angiosperms is an indicator of the homology of their novel callosic pollen tube walls and callose plugs. The data suggest that CalS5 had transient expression and pollen-specific functions in early seed plants and was then recruited to novel expression patterns and functions within pollen tube walls in an ancestor of extant angiosperms. PMID:21722365

Prevalence of pollen-induced allergic rhinitis with high pollen exposure in grasslands of northern China.

PubMed

Wang, X-Y; Ma, T-T; Wang, X-Y; Zhuang, Y; Wang, X-D; Ning, H-Y; Shi, H-Y; Yu, R-L; Yan, D; Huang, H-D; Bai, Y-F; Shan, G-L; Zhang, B; Song, Q-K; Zhang, Y-F; Zhang, T-J; Jia, D-Z; Liu, X-L; Kang, Z-X; Yan, W-J; Yang, B-T; Bao, X-Z; Sun, S-H; Zhang, F-F; Yu, W-H; Bai, C-L; Wei, T; Yang, T; Ma, T-Q; Wu, X-B; Liu, J-G; Du, H; Zhang, L; Yan, Y; Wang, D-Y

2018-06-01

The aim of this study was to investigate the prevalence of epidemiologic and physician-diagnosed pollen-induced AR (PiAR) in the grasslands of northern China and to study the impact of the intensity and time of pollen exposure on PiAR prevalence. A multistage, clustered and proportionately stratified random sampling with a field interviewer-administered survey study was performed together with skin prick tests (SPT) and measurements of the daily pollen count. A total of 6043 subjects completed the study, with a proportion of 32.4% epidemiologic AR and 18.5% PiAR. The prevalence was higher in males than females (19.6% vs 17.4%, P = .024), but no difference between the two major residential and ethnic groups (Han and Mongolian) was observed. Subjects from urban areas showed higher prevalence of PiAR than rural areas (23.1% vs 14.0%, P < .001). Most PiAR patients were sensitized to two or more pollens (79.4%) with artemisia, chenopodium, and humulus scandens being the most common pollen types, which were similarly found as the top three sensitizing pollen allergens by SPT. There were significant regional differences in the prevalence of epidemiologic AR (from 18.6% to 52.9%) and PiAR (from 10.5% to 31.4%) among the six areas investigated. PiAR symptoms were positively associated with pollen counts, temperature, and precipitation (P < .05), but negatively with wind speed and pressure P < .05). Pollen-induced AR (PiAR) prevalence in the investigated region is extremely high due to high seasonal pollen exposure, which was influenced by local environmental and climate conditions. © 2018 The Authors. Allergy Published by John Wiley and Sons Ltd.

Annual and intradiurnal variation of dominant airborne pollen and the effects of meteorological factors in Çeşme (Izmir, Turkey).

PubMed

Uguz, Ulas; Guvensen, Aykut; Tort, Nedret Sengonca

2017-09-30

In this present study, airborne pollen in Çeşme was investigated between February 17, 2012 and February 17, 2014 using the volumetric method. Çeşme, one of Turkey's most important tourism centers, which attracts numerous local and foreign tourists each year, is a district of Izmir, a province in the western part of Turkey. During the 2-year study, 12,905 pollen grains belonging to 64 taxa (33 arboreal, 31 non-arboreal plants) were detected. However, the 2-year data results revealed that the taxa with the pollen concentration more than 4% in the atmosphere were Cupressaceae/Taxaceae (4268 pollen, 33.07%), Olea europaea (1614 pollen grains, 12.51%), Pinaceae (1085 pollen grains, 8.41%), Quercus spp. (1081 pollen grains, 8.38%), Pistacia spp. (743 pollen grains, 5.76%), and Poaceae (557 pollen grains, 4.32%), all of which comprised 72.44% of the total count. The relationship between the daily pollen counts belonging to these six taxa and the hourly average temperature (°C), daily precipitation (mm), relative humidity (%), and wind speed (km/h) was assessed using the Spearman correlation test, and significant results were determined. During the study, the intradiurnal distribution of the aforementioned pollen varied. The highest pollen concentration was detected between 11:00 a.m. and 6:00 p.m. (first year 30.3%; second year 30.1%).

IgE, IgG4 and IgA specific to Bet v 1-related food allergens do not predict oral allergy syndrome.

PubMed

Guhsl, E E; Hofstetter, G; Lengger, N; Hemmer, W; Ebner, C; Fröschl, R; Bublin, M; Lupinek, C; Breiteneder, H; Radauer, C

2015-01-01

Birch pollen-associated plant food allergy is caused by Bet v 1-specific IgE, but presence of cross-reactive IgE to related allergens does not predict food allergy. The role of other immunoglobulin isotypes in the birch pollen-plant food syndrome has not been investigated in detail. Bet v 1-sensitized birch pollen-allergic patients (n = 35) were diagnosed for food allergy by standardized interviews, skin prick tests, prick-to-prick tests and ImmunoCAP. Concentrations of allergen-specific IgE, IgG1, IgG4 and IgA to seven Bet v 1-related food allergens were determined by ELISA. Bet v 1, Cor a 1, Mal d 1 and Pru p 1 bound IgE from all and IgG4 and IgA from the majority of sera. Immunoglobulins to Gly m 4, Vig r 1 and Api g 1.01 were detected in <65% of the sera. No significant correlation was observed between plant food allergy and increased or reduced levels of IgE, IgG1, IgG4 or IgA specific to most Bet v 1-related allergens. Api g 1-specific IgE was significantly (P = 0.01) elevated in celeriac-allergic compared with celeriac-tolerant patients. Likewise, frequencies of IgE (71% vs 15%; P = 0.01) and IgA (86% vs 38%; P = 0.04) binding to Api g 1.01 were increased. Measurements of allergen-specific immunoglobulins are not suitable for diagnosing Bet v 1-mediated plant food allergy to hazelnut and Rosaceae fruits. In contrast, IgE and IgA to the distantly related allergen Api g 1 correlate with allergy to celeriac. © 2014 The Authors. Allergy Published by John Wiley & Sons Ltd.

Pollen-mediated gene flow from glyphosate-resistant common waterhemp (Amaranthus rudis Sauer): consequences for the dispersal of resistance genes

PubMed Central

Sarangi, Debalin; Tyre, Andrew J.; Patterson, Eric L.; Gaines, Todd A.; Irmak, Suat; Knezevic, Stevan Z.; Lindquist, John L.; Jhala, Amit J.

2017-01-01

Gene flow is an important component in evolutionary biology; however, the role of gene flow in dispersal of herbicide-resistant alleles among weed populations is poorly understood. Field experiments were conducted at the University of Nebraska-Lincoln to quantify pollen-mediated gene flow (PMGF) from glyphosate-resistant (GR) to -susceptible (GS) common waterhemp using a concentric donor-receptor design. More than 130,000 common waterhemp plants were screened and 26,199 plants were confirmed resistant to glyphosate. Frequency of gene flow from all distances, directions, and years was estimated with a double exponential decay model using Generalized Nonlinear Model (package gnm) in R. PMGF declined by 50% at <3 m distance from the pollen source, whereas 90% reduction was found at 88 m (maximum) depending on the direction of the pollen-receptor blocks. Amplification of the target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), was identified as the mechanism of glyphosate resistance in parent biotype. The EPSPS gene amplification was heritable in common waterhemp and can be transferred via PMGF, and also correlated with glyphosate resistance in pseudo-F2 progeny. This is the first report of PMGF in GR common waterhemp and the results are critical in explaining the rapid dispersal of GR common waterhemp in Midwestern United States. PMID:28327669

A new link between stress response and nucleolar function during pollen development in Arabidopsis mediated by AtREN1 protein.

PubMed

Reňák, David; Gibalová, Antónia; Solcová, Katarzyna; Honys, David

2014-03-01

Heat shock transcription factors (Hsfs) are involved in multiple aspects of stress response and plant growth. However, their role during male gametophyte development is largely unknown, although the generative phase is the most sensitive and critical period in the plant life cycle. Based on a wide screen of T-DNA mutant lines, we identified the atren1 mutation (restricted to nucleolus1) in early male gametophytic gene At1g77570, which has the closest homology to HSFA5 gene, the member of a heat shock transcription factor (HSF) gene family. The mutation causes multiple defects in male gametophyte development in both structure and function. Because the mutation disrupts an early acting (AtREN1) gene, these pollen phenotype abnormalities appear from bicellular pollen stage to pollen maturation. Moreover, the consequent progamic phase is compromised as well as documented by pollen germination defects and limited transmission via male gametophyte. In addition, atren1/- plants are defective in heat stress (HS) response and produce notably higher proportion of aberrant pollen grains. AtREN1 protein is targeted specifically to the nucleolus that, together with the increased size of the nucleolus in atren1 pollen, suggests that it is likely to be involved in ribosomal RNA biogenesis or other nucleolar functions. © 2013 John Wiley & Sons Ltd.

Implementation of pre-seasonal sublingual immunotherapy with a five-grass pollen tablet during optimal dosage assessment.

PubMed

Horak, F; Jaeger, S; Worm, M; Melac, M; Didier, A

2009-03-01

The optimal dose (300IR) of a five-grass pollen sublingual immunotherapy tablet in terms of efficacy was previously demonstrated from the first pollen season. Here, we aim to confirm whether this dose remained optimal during the peak of the pollen season by assessing the efficacy and quality of life data. A total of 628 subjects with grass pollen rhinoconjunctivitis were randomized in a double-blind, placebo-controlled, multi-centre, pan-European trial. Subjects received once-daily tablets (Stallergenes, Antony, France) of 100IR, 300IR, 500IR or placebo, starting 4 months before and throughout the 2005 grass pollen season. The pollen season was defined as the first day of 3 consecutive days with a grass pollen count above 30 grains/m(3) of air, recorded using Hirst-type volumetric pollen traps, to the last day before 3 consecutive days with a pollen count below 30 grains/m(3). The grass pollen season lasted an average of 30 days, with a peak of 12 days. The mean treatment duration before the grass pollen season was similar in the four treatment groups (121.4+/-31.1 to 128.6+/-15.4 days in the safety population). Both the 300IR and 500IR groups had highly significant improvements in Rhinoconjunctivitis Total Symptom Score (RTSS) vs. placebo at the peak pollen season (P=0.0005 and 0.0014, respectively), which agreed with improvements in RTSS in the primary evaluations. The average RTSS scores were slightly elevated during the peak pollen season in all treatment groups. The overall Rhinoconjunctivitis Quality of Life Questionnaire score confirmed the optimal dosage 300IR at peak (P<0.0001) and at the end (P< or =0.0031) of the pollen season. All doses were well tolerated. At the peak pollen season, the efficacy and quality of life data for both 300IR and 500IR groups was significantly improved vs. the placebo group. These results confirm the conclusions of the primary evaluations and validate the use of 300IR tablets for clinical practice.

Estimates of common ragweed pollen emission and dispersion over Europe using RegCM-pollen model

NASA Astrophysics Data System (ADS)

Liu, L.; Solmon, F.; Vautard, R.; Hamaoui-Laguel, L.; Torma, Cs. Zs.; Giorgi, F.

2015-11-01

Common ragweed (Ambrosia artemisiifolia L.) is a highly allergenic and invasive plant in Europe. Its pollen can be transported over large distances and has been recognized as a significant cause of hayfever and asthma (D'Amato et al., 2007; Burbach et al., 2009). To simulate production and dispersion of common ragweed pollen, we implement a pollen emission and transport module in the Regional Climate Model (RegCM) version 4 using the framework of the Community Land Model (CLM) version 4.5. In the online model environment where climate is integrated with dispersion and vegetation production, pollen emissions are calculated based on the modelling of plant distribution, pollen production, species-specific phenology, flowering probability, and flux response to meteorological conditions. A pollen tracer model is used to describe pollen advective transport, turbulent mixing, dry and wet deposition. The model is then applied and evaluated on a European domain for the period 2000-2010. To reduce the large uncertainties notably due to ragweed density distribution on pollen emission, a calibration based on airborne pollen observations is used. Resulting simulations show that the model captures the gross features of the pollen concentrations found in Europe, and reproduce reasonably both the spatial and temporal patterns of flowering season and associated pollen concentrations measured over Europe. The model can explain 68.6, 39.2, and 34.3 % of the observed variance in starting, central, and ending dates of the pollen season with associated root mean square error (RMSE) equal to 4.7, 3.9, and 7.0 days, respectively. The correlation between simulated and observed daily concentrations time series reaches 0.69. Statistical scores show that the model performs better over the central Europe source region where pollen loads are larger. From these simulations health risks associated common ragweed pollen spread are then evaluated through calculation of exposure time above health-relevant threshold levels. The total risk area with concentration above 5 grains m-3 takes up 29.5 % of domain. The longest exposure time occurs on Pannonian Plain, where the number of days per year with the daily concentration above 20 grains m-3 exceeds 30.

Testing Nonthermal Plasma for Decontamination of Sensitive Weapons Systems and Platforms

DTIC Science & Technology

2011-06-01

hardy  materials,  primarily  composed  of  carbon.  The  elevation  of   pollen   counts  has  strong   220   seasonality...12   4.4.  Removal  of   Pollen  Grains...Ambrosia   Pollen  Grain  .....................  16   Figure  11b.  Image  of  Ambrosia   Pollen  Grains  deposited  on  a

Pollen S-locus F-box proteins of Petunia involved in S-RNase-based self-incompatibility are themselves subject to ubiquitin-mediated degradation.

PubMed

Sun, Penglin; Li, Shu; Lu, Dihong; Williams, Justin S; Kao, Teh-Hui

2015-07-01

Many flowering plants show self-incompatibility, an intra-specific reproductive barrier by which pistils reject self-pollen to prevent inbreeding and accept non-self pollen to promote out-crossing. In Petunia, the polymorphic S-locus determines self/non-self recognition. The locus contains a gene encoding an S-RNase, which controls pistil specificity, and multiple S-locus F-box (SLF) genes that collectively control pollen specificity. Each SLF is a component of an SCF (Skp1/Cullin/F-box) complex that is responsible for mediating degradation of non-self S-RNase(s), with which the SLF interacts, via the ubiquitin-26S proteasome pathway. A complete set of SLFs is required to detoxify all non-self S-RNases to allow cross-compatible pollination. Here, we show that SLF1 of Petunia inflata is itself subject to degradation via the ubiquitin-26S proteasome pathway, and identify an 18 amino acid sequence in the C-terminal region of S2 -SLF1 (SLF1 of S2 haplotype) that contains a degradation motif. Seven of the 18 amino acids are conserved among all 17 SLF proteins of S2 haplotype and S3 haplotype involved in pollen specificity, suggesting that all SLF proteins are probably subject to similar degradation. Deleting the 18 amino acid sequence from S2 -SLF1 stabilized the protein but abolished its function in self-incompatibility, suggesting that dynamic cycling of SLF proteins is an integral part of their function in self-incompatibility. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Nectar alkaloids decrease pollination and female reproduction in a native plant.

PubMed

Adler, Lynn S; Irwin, Rebecca E

2012-04-01

The evolution of floral traits may be shaped by a community of floral visitors that affect plant fitness, including pollinators and floral antagonists. The role of nectar in attracting pollinators has been extensively studied, but its effects on floral antagonists are less understood. Furthermore, the composition of non-sugar nectar components, such as secondary compounds, may affect plant reproduction via changes in both pollinator and floral antagonist behavior. We manipulated the nectar alkaloid gelsemine in wild plants of the native perennial vine Gelsemium sempervirens. We crossed nectar gelsemine manipulations with a hand-pollination treatment, allowing us to determine the effect of both the trait and the interaction on plant female reproduction. We measured pollen deposition, pollen removal, and nectar robbing to assess whether gelsemine altered the behavior of mutualists and antagonists. High nectar gelsemine reduced conspecific pollen receipt by nearly half and also reduced the proportion of conspecific pollen grains received, but had no effect on nectar robbing. Although high nectar gelsemine reduced pollen removal, an estimate of male reproduction, by one-third, this effect was not statistically significant. Fruit set was limited by pollen receipt. However, this effect varied across sites such that the sites that were most pollen-limited were also the sites where nectar alkaloids had the least effect on pollen receipt, resulting in no significant effect of nectar alkaloids on fruit set. Finally, high nectar gelsemine significantly reduced seed weight; however, this effect was mediated by a mechanism other than pollen limitation. Taken together, our work suggests that nectar alkaloids are more costly than beneficial in our system, and that relatively small-scale spatial variation in trait effects and interactions could determine the selective impacts of traits such as nectar composition.

Influence of long-distance seed dispersal on the genetic diversity of seed rain in fragmented Pinus densiflora populations relative to pollen-mediated gene flow.

PubMed

Ozawa, Hajime; Watanabe, Atsushi; Uchiyama, Kentaro; Saito, Yoko; Ide, Yuji

2013-01-01

Long-distance dispersal (LDD) of seeds has a critical impact on species survival in patchy landscapes. However, relative to pollen dispersal, empirical data on how seed LDD affects genetic diversity in fragmented populations have been poorly reported. Thus, we attempted to indirectly evaluate the influence of seed LDD by estimating maternal and paternal inbreeding in the seed rain of fragmented 8 Pinus densiflora populations. In total, the sample size was 458 seeds and 306 adult trees. Inbreeding was estimated by common parentage analysis to evaluate gene flow within populations and by sibship reconstruction analysis to estimate gene flow within and among populations. In the parentage analysis, the observed probability that sampled seeds had the same parents within populations was significantly larger than the expected probability in many populations. This result suggested that gene dispersal was limited to within populations. In the sibship reconstruction, many donors both within and among populations appeared to contribute to sampled seeds. Significant differences in sibling ratios were not detected between paternity and maternity. These results suggested that seed-mediated gene flow and pollen-mediated gene flow from outside population contributed some extent to high genetic diversity of the seed rain (H E > 0.854). We emphasize that pine seeds may have excellent potential for gene exchange within and among populations.

Coconut (Cocos nucifera l.) pollen cryopreservation.

PubMed

Karun, A; Sjini, K K; Niral, V; Amarnth, C H; Remya, P; Rajesh, M K; Samsudeen, K; Jerard, B A; Engelmann, F

2014-01-01

Coconut genetic resources are threatened by pests and pathogens, natural hazards and human activities. Cryopreservation is the only method allowing the safe and cost-effective long-term conservation of recalcitrant seed species such as coconut. The objective of this work was to test the effect of cryopreservation and of cryostorage duration on coconut pollen germination and fertility. Pollen of two coconut varieties (West Coast Tall WWCTW and Chowghat Orange Dwarf CODC) was collected in March-May over three successive years, desiccated to 7.5 % moisture content (FW) and cryopreserved by direct immersion in liquid nitrogen. Germination and pollen tube length (PTL) of desiccated and cryopreserved pollen were not significantly different for both WCT and COD over the three harvest months of the three consecutive years of study. Pollen germination ranged from 24 to 32 % in desiccated pollen whereas it was between 26 and 29 % in cryopreserved COD pollen. In the case of WCT, germination ranged from 30 to 31 % in desiccated pollen, while it was between 28 and 32 % in cryopreserved pollen. PTL of cryopreserved pollen ranged between 224-390 nm and 226-396 mm for COD and WCT, respectively. Germination of COD pollen varied between 29.0 and 44.1 % after 4 years and 1.0/1.5 years cryostorage, respectively. Germination of WCT pollen did not change significantly between 0 and 6 years cryostorage, being comprised between 32 (24 h) and 40 % (1.5 years). Germination and vigour of cryopreserved pollen were generally higher compared to that of pollen dried in oven and non-cryopreserved. Normal seed set was observed in COD and WCT palms using pollen cryostored for 6 months and 4 years. Cryopreserved pollen of five Tall and five Dwarf accessions displayed 24-31 % and 25-49 % germination, respectively. These results show that it is now possible to establish pollen cryobanks to contribute to coconut germplasm long-term conservation.

Pollen density on the stigma affects endogenous gibberellin metabolism, seed and fruit set, and fruit quality in Pyrus pyrifolia.

PubMed

Zhang, Caixi; Tateishi, Naoya; Tanabe, Kenji

2010-10-01

To clarify the relationship between pollen density and gametophytic competition in Pyrus pyrifolia, gametophytic performance, gibberellin metabolism, fruit set, and fruit quality were investigated by modifying P. pyrifolia pollen grain number and density with Lycopodium spores. Higher levels of pollen density improved seed viability, fruit set, and fruit quality. Treatments with the highest pollen density showed a significantly increased fruit growth rate and larger fruit at harvest. High pollen density increased germination rate and gave a faster pollen tube growth, both in vivo and in vitro. Endogenous gibberellin (GA) concentrations increased in pollen tubes soon after germination and the concentration of two growth-active GAs, GA(3), and GA(4), was positively correlated to final fruit size, cell numbers in the mesocarp, and pollen tube growth rate. These two GAs appear to be biosynthesized de novo in pollen tube and are the main pollen-derived bioactive GAs found after pollen germination. GA(1) levels in the pollen tube appear to be related to a pollen-style interaction that occurred after the pollen grains landed on the stigma.

Reported symptoms to peanut between 4 and 8 years among children sensitized to peanut and birch pollen - results from the BAMSE birth cohort.

PubMed

Asarnoj, A; Ostblom, E; Ahlstedt, S; Hedlin, G; Lilja, G; van Hage, M; Wickman, M

2010-02-01

Specific IgE tests are sometimes difficult to interpret due to structural similarities between certain food and pollen allergens. This may be the reason why concomitant sensitization to peanut and birch pollen is frequently seen. The aim of this study was to investigate reported symptoms to peanut- and birch pollen in relation to sensitization. The data originate from 1928 children in the BAMSE birth cohort. Background factors and clinical parameters were obtained and the levels of IgE antibodies to peanut and birch pollen measured at 4 and 8 years. IgE antibodies to peanut were found in 5.5% and 7.4% of the children at 4 and 8 years, respectively. The IgE antibody levels to peanut were higher in children sensitized to peanut but not birch than in children sensitized to peanut and birch among both 4- and 8-year-olds (P = 0.093 and P = 0.003, respectively). Eight-year-olds sensitized to peanut but not birch, more often reported symptoms to peanut than children sensitized to both peanut and birch pollen (76%vs 46%, P = 0.002). The probability of reported symptoms to peanut increased significantly with increasing IgE levels to peanut, especially in 8-year-olds not sensitized to birch. Children sensitized to both peanut and birch pollen are less likely to report symptoms to peanut than children sensitized to peanut but not to birch pollen at 8 years. This is likely due to cross reactions between birch pollen and peanut and can explain the high sensitization rate to peanut in areas where birch trees are common.

[Correlation between the visiting rate of patients with allergic rhinitis and airborne pollen concentrations in Beijing in recent 3 years].

PubMed

Hu, W N; Zhu, L; Xie, L F; Zhang, F Z; Bai, M Y; Wang, N; Sun, Z W

2017-01-07

Objective: To evaluate the daily airborne pollen concentrations and visiting rate of patients with allergic rhinitis (AR) and their correlation during 2012-2014 in Beijing. Methods: Daily airborne pollen concentrations (55 998 numbers in total and 549 numbers in average) and its constitution from April to September each year (2012 to 2014) were compared. The number of patients with AR (44 203 in total) who visited the outpatient department of Otorhinolaryngology Head and Neck Surgery, Peking University Third Hospital between January 2012 and December 2014 was analyzed by month. Using SPSS 22.0 software, Kruskal - Wallis test was done for the comparison of visiting rate of patients with AR and airborne pollen concentrations. Correlation analysis between them was made as well. Results: χ(2) value of airborne pollen concentrations between different months in 2012 to 2014 was 110.7, 108.4 and 121.4, respectively; all P <0.01. The airborne pollen concentrations had two peaks per year, respectively: April to May, August to September. χ(2) value of visiting rate of patients with AR between different months in 2012 to 2014 was 175.0, 185.1 and 134.5, respectively; all P <0.01. Visiting rate of patients with AR showed two scattering peaks each year, respectively: April to May, August to September. The highest pollen concentration of spring (April to May) was in early and middle April. Tree pollen was the major portion in spring, which were poplar pollen, pine tree pollen, ash tree pollen, cypress tree pollen and birch trees pollen. The highest pollen concentration of autumn (August to September) was in late August and early September. Weed pollen was the major portion in summer and autumn, which were artemisia pollen, chenopodiaceae pollen and humulus japonicas pollen. The visiting rate of patients with AR showed significant correlation with airborne pollen concentrations ( r value was 0.537, 0.484 and 0.566, respectively; all P <0.01). Conclusion: The visiting rate of patients with AR showed positive correlation with airborne pollen concentrations in recent three years.

Development and characterization of a recombinant, hypoallergenic, peptide-based vaccine for grass pollen allergy.

PubMed

Focke-Tejkl, Margarete; Weber, Milena; Niespodziana, Katarzyna; Neubauer, Angela; Huber, Hans; Henning, Rainer; Stegfellner, Gottfried; Maderegger, Bernhard; Hauer, Martina; Stolz, Frank; Niederberger, Verena; Marth, Katharina; Eckl-Dorna, Julia; Weiss, Richard; Thalhamer, Josef; Blatt, Katharina; Valent, Peter; Valenta, Rudolf

2015-05-01

Grass pollen is one of the most important sources of respiratory allergies worldwide. This study describes the development of a grass pollen allergy vaccine based on recombinant hypoallergenic derivatives of the major timothy grass pollen allergens Phl p 1, Phl p 2, Phl p 5, and Phl p 6 by using a peptide-carrier approach. Fusion proteins consisting of nonallergenic peptides from the 4 major timothy grass pollen allergens and the PreS protein from hepatitis B virus as a carrier were expressed in Escherichia coli and purified by means of chromatography. Recombinant PreS fusion proteins were tested for allergenic activity and T-cell activation by means of IgE serology, basophil activation testing, T-cell proliferation assays, and xMAP Luminex technology in patients with grass pollen allergy. Rabbits were immunized with PreS fusion proteins to characterize their immunogenicity. Ten hypoallergenic PreS fusion proteins were constructed, expressed, and purified. According to immunogenicity and induction of allergen-specific blocking IgG antibodies, 4 hypoallergenic fusion proteins (BM321, BM322, BM325, and BM326) representing Phl p 1, Phl p 2, Phl p 5, and Phl p 6 were included as components in the vaccine termed BM32. BM321, BM322, BM325, and BM326 showed almost completely abolished allergenic activity and induced significantly reduced T-cell proliferation and release of proinflammatory cytokines in patients' PBMCs compared with grass pollen allergens. On immunization, they induced allergen-specific IgG antibodies, which inhibited patients' IgE binding to all 4 major allergens of grass pollen, as well as allergen-induced basophil activation. A recombinant hypoallergenic grass pollen allergy vaccine (BM32) consisting of 4 recombinant PreS-fused grass pollen allergen peptides was developed for safe immunotherapy of grass pollen allergy. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Extensive contemporary pollen-mediated gene flow in two herb species, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient in a meadow landscape

PubMed Central

Matter, Philippe; Kettle, Chris J.; Ghazoul, Jaboury; Pluess, Andrea R.

2013-01-01

Background and Aims Genetic connectivity between plant populations allows for exchange and dispersal of adaptive genes, which can facilitate plant population persistence particularly in rapidly changing environments. Methods Patterns of historic gene flow, flowering phenology and contemporary pollen flow were investigated in two common herbs, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient of 1200–1800 m a.s.l. over a distance of 1 km among five alpine meadows in Switzerland. Key Results Historic gene flow was extensive, as revealed by Fst values of 0·01 and 0·007 in R. bulbosus and T. montanum, respectively, by similar levels of allelic richness among meadows and by the grouping of all individuals into one genetic cluster. Our data suggest contemporary pollen flow is not limited across altitudes in either species but is more pronounced in T. montanum, as indicated by the differential decay of among-sibships correlated paternity with increasing spatial distance. Flowering phenology among meadows was not a barrier to pollen flow in T. montanum, as the large overlap between meadow pairs was consistent with the extensive pollen flow. The smaller flowering overlap among R. bulbosus meadows might explain the slightly more limited pollen flow detected. Conclusions High levels of pollen flow among altitudes in both R. bulbosus and T. montanum should facilitate exchange of genes which may enhance adaptive responses to rapid climate change. PMID:23408831

Transcriptome analysis reveals the same 17 S-locus F-box genes in two haplotypes of the self-incompatibility locus of Petunia inflata.

PubMed

Williams, Justin S; Der, Joshua P; dePamphilis, Claude W; Kao, Teh-Hui

2014-07-01

Petunia possesses self-incompatibility, by which pistils reject self-pollen but accept non-self-pollen for fertilization. Self-/non-self-recognition between pollen and pistil is regulated by the pistil-specific S-RNase gene and by multiple pollen-specific S-locus F-box (SLF) genes. To date, 10 SLF genes have been identified by various methods, and seven have been shown to be involved in pollen specificity. For a given S-haplotype, each SLF interacts with a subset of its non-self S-RNases, and an as yet unknown number of SLFs are thought to collectively mediate ubiquitination and degradation of all non-self S-RNases to allow cross-compatible pollination. To identify a complete suite of SLF genes of P. inflata, we used a de novo RNA-seq approach to analyze the pollen transcriptomes of S2-haplotype and S3-haplotype, as well as the leaf transcriptome of the S3S3 genotype. We searched for genes that fit several criteria established from the properties of the known SLF genes and identified the same seven new SLF genes in S2-haplotype and S3-haplotype, suggesting that a total of 17 SLF genes constitute pollen specificity in each S-haplotype. This finding lays the foundation for understanding how multiple SLF genes evolved and the biochemical basis for differential interactions between SLF proteins and S-RNases. © 2014 American Society of Plant Biologists. All rights reserved.

Two Membrane-Anchored Aspartic Proteases Contribute to Pollen and Ovule Development1[OPEN

PubMed Central

Gao, Hui; Zhang, Yinghui; Wang, Wanlei; Zhao, Keke; Liu, Chunmei; Bai, Lin; Li, Rui

2017-01-01

Aspartic proteases are a class of proteolytic enzymes with conserved aspartate residues, which are implicated in protein processing, maturation, and degradation. Compared with yeast and animals, plants possess a larger aspartic protease family. However, little is known about most of these enzymes. Here, we characterized two Arabidopsis (Arabidopsis thaliana) putative glycosylphosphatidylinositol (GPI)-anchored aspartic protease genes, A36 and A39, which are highly expressed in pollen and pollen tubes. a36 and a36 a39 mutants display significantly reduced pollen activity. Transmission electron microscopy and terminal-deoxynucleotidyl transferase-mediated nick end labeling assays further revealed that the unviable pollen in a36 a39 may undergo unanticipated apoptosis-like programmed cell death. The degeneration of female gametes also occurred in a36 a39. Aniline Blue staining, scanning electron microscopy, and semi in vitro guidance assays indicated that the micropylar guidance of pollen tubes is significantly compromised in a36 a39. A36 and A39 that were fused with green fluorescent protein are localized to the plasma membrane and display punctate cytosolic localization and colocalize with the GPI-anchored protein COBRA-LIKE10. Furthermore, in a36 a39, the abundance of highly methylesterified homogalacturonans and xyloglucans was increased significantly in the apical pollen tube wall. These results indicate that A36 and A39, two putative GPI-anchored aspartic proteases, play important roles in plant reproduction in Arabidopsis. PMID:27872247

Some physical properties of teosinte (Zea mays subsp. parviglumis) pollen.

PubMed

Aylor, Donald E; Baltazar, Baltazar M; Schoper, John B

2005-09-01

In parts of the world where teosinte and maize are grown in close proximity, there is concern about gene flow between them. Pollen is the primary vehicle for gene flow. Quantifying the biophysical properties of pollen, such as its settling speed and dehydration rate, is important for evaluating outcrossing potential. These properties were measured for teosinte (Zea mays subsp. parviglumis) pollen. Pollen was found to have an average settling speed of 0.165 m s(-1), which agrees well with theoretical values based on the size of the pollen grains. The conductance of the pollen wall for water was derived from the time rate of change of pollen grain size and gave an average conductance of 3.42x10(-4) m s(-1). Water potential, psi, of teosinte pollen was determined at various values of relative water content (dry-weight basis), theta, by using a thermocouple psychrometer and by allowing samples of pollen to come to vapour equilibrium with various saturated salt solutions. Non-linear regression analysis of the data yielded psi (MPa) = -4.13 theta(-1.23) (r2=0.77). Results for conductance and psi were incorporated into a model equation for the rate of water loss from pollen grains, which yielded results that agreed well (r2=0.96) with observations of water loss from pollen grains in air. The data reported here are important building blocks in a model of teosinte pollen movement and should be helpful in establishing the main factors influencing the degree and the direction of pollination between teosinte populations and between maize and teosinte.

Hydrogen ions associated with the dry deposition of pollen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noll, K.E.; Khalili, E.K.

The data provided in this paper demonstrates that pollen can generate significant amounts of hydrogen ions when added to water and that the deposition of tree pollen in forested areas represents a significant hydrogen ion source. Measurements of dry deposition of pollen were made during the months of May and June, 1987 in Northern Wisconsin, using a smooth surrogate surface. Rain samples were also collected. Deposited particles were weighed to determine mass fluxes, then washed and ion chromatographed for SO {sub 4} = and NO {sub 3} {minus} analysis. Species of pollen collected from different types of trees during themore » sampling period were analyzed for SO{sub 4} = NO {sub 3} and other trace constituents. The micrograms of hydrogen ions (protons) generated per gram for different types of pollen added to water, were measured. From 56 to 566 gm were generated per gram or pollen added. The amount generated varied with pollen type. Based on this information, the equivalent protons from the dry deposition of pollen were calculated and compared with the wet deposition proton data. The sulfate, nitrate, and protons associated with dry deposition were of a magnitude comparable with wet deposition.« less

[Literature review of the dispersal of transgenes from genetically modified maize].

PubMed

Ricroch, Agnès; Bergé, Jean Baptiste; Messéan, Antoine

2009-10-01

This article aims at reviewing the theoretical and experimental data published in 562 publications referring to genetically modified (GM) maize dispersal. Our choice was limited to this since in the European Union (EU), GM maize is the only GM crop currently grown commercially. The pollen dispersal of transgenic maize is due to two factors: (i) pollen-mediated gene flow; (ii) seed admixture during harvest and post-harvest processes. The pollen dispersal decreases rapidly with the distance from GM plots. Climatic and topographic factors and factors of relative density between GM and non-GM maize plots impact on the pollen dispersal. The combination of both isolation distance and flowering date between source plots and sink plots limits the adventitious presence of transgenes in non-GM plots. All publications we reviewed demonstrate that the EU 0.9% threshold is technically manageable if the measures of isolation distances as well as harvesting and post harvesting processes and fully synchronous flowering are implemented.

Transient Expression of Chimeric Fluorescent Reporter Proteins in Pollen Tubes to Study Protein Polar Secretion and Dynamics.

PubMed

Zhong, Guitao; Liu, Ronghe; Zhuang, Menglong; Wang, Hao

2017-01-01

Transient expression of chimeric fluorescent reporter proteins by biolistic bombardment is a quick and useful procedure for studying subcellular protein localization and dynamics in plants. It is especially beneficial in specific plant cells which are not suitable for protoplast-based and Agrobacterium-mediated protein transient expression. Polar protein secretion and vesicular trafficking play essential functions for cell polarization and tip growth. The growing pollen tube is regarded as an ideal model plant cell system to study the machinery and regulation of polar protein trafficking and targeting. A large amount of newly synthesized proteins are packed and polarly transported to the apical region to support the rapid and highly polarized tip growth. Here, we described a detailed step-by-step protocol for the transient expression of chimeric fluorescent reporter proteins in growing Arabidopsis and tobacco pollen tubes to study polar transportation logistics and mechanisms. In addition, we have optimized the Arabidopsis and tobacco in vitro pollen germination medium and the conditions to maximize the efficiency of protein expression. As a proof of concept, we have used this protocol to express actin microfilament and late endosomal fluorescent markers in Arabidopsis and tobacco pollen tubes.

Cytomechanical properties of papaver pollen tubes are altered after self-incompatibility challenge.

PubMed

Geitmann, Anja; McConnaughey, William; Lang-Pauluzzi, Ingeborg; Franklin-Tong, Vernonica E; Emons, Anne Mie C

2004-05-01

Self-incompatibility (SI) in Papaver rhoeas triggers a ligand-mediated signal transduction cascade, resulting in the inhibition of incompatible pollen tube growth. Using a cytomechanical approach we have demonstrated that dramatic changes to the mechanical properties of incompatible pollen tubes are stimulated by SI induction. Microindentation revealed that SI resulted in a reduction of cellular stiffness and an increase in cytoplasmic viscosity. Whereas the former cellular response is likely to be the result of a drop in cellular turgor, we hypothesize that the latter is caused by as yet unidentified cross-linking events. F-actin rearrangements, a characteristic phenomenon for SI challenge in Papaver, displayed a spatiotemporal gradient along the pollen tube; this suggests that signal propagation occurs in a basipetal direction. However, unexpectedly, local application of SI inducing S-protein did not reveal any evidence for localized signal perception in the apical or subapical regions of the pollen tube. To our knowledge this represents the first mechanospatial approach to study signal propagation and cellular responses in a well-characterized plant cell system. Our data provide the first evidence for mechanical changes induced in the cytoplasm of a plant cell stimulated by a defined ligand.

Pollen flow of wheat under natural conditions in the Huanghuai River Wheat Region, China

PubMed Central

Sun, Ai-Qing; Zhang, Chun-Qing; Wu, Cheng-Lai; Gao, Qing-Rong

2015-01-01

abstract The transgenic pollen spread is the main pathway of transgenic plant gene flow. The maximum distance of pollen dispersal (horizontal), the spatial dynamics of pollen movement (vertical), and the patterns of pollen dispersal are important considerations in biosafety assessments of genetically modified crops. To evaluate wheat (Triticum aestivum) pollen dispersal, we measured the pollen suspension velocity and analyzed pollen dispersal patterns under natural conditions in the Huanghuai River wheat-growing region in 2009. The pollen suspension velocity was 0.3–0.4 m/s. The highest pollen densities were detected in the north, northwest, and south of the pollen source. Pollen was dispersed over distances greater than 245 m in the northwest and northeast directions. At the pollen source center, pollen density decreased with increasing vertical height. In the north of the pollen source, the pollen density from 65 m to 225 m showed a wave-mode decrease with increasing height. The horizontal transport of pollen over longer distances fitted polynomial equations. In the north, the pollen density was highest at 45 m from the pollen source, and decreased with increasing distance. In the northwest, the pollen density showed a double-peak trend. In the northeast, pollen density was highest from 45 m to 125 m from the source. Wind speeds greater than the pollen suspension velocity and the duration of continuous gusts were the main factors affecting pollen dispersal. This information will be useful for determining the spatial isolation distances for hybrid seed production and for the commercial production of transgenic wheat. PMID:25658025

The impact of sulfur dioxide on plant sexual reproduction: in vivo and in vitro effects compared

DOE Office of Scientific and Technical Information (OSTI.GOV)

DuBay, D.T.; Murdy, W.H.

1983-01-01

In Lepidium virginicum L., exposure of pollen to 0.6 ppm sulfur dioxide (SO/sub 2/) for 4 h reduced pollen germination in vitro 94% from the control, whereas exposure to 0.6 ppm SO/sub 2/ for 2, 4, and 8 h during flowering reduced pollen germination in vivo 50% from the control, but did not affect seed set.An interaction between SO/sub 2/ and water may have caused the inhibition of pollen germination in a liquid culture medium, as well as on the moist surface of an intact stigma. However, the results suggest that the use of pollen germination and pollen tube elongationmore » in vitro to asses the direct effects of SO/sub 2/ on plant sexual reproduction in vivo is not valid.« less

Impact of sulfur dioxide on plant sexual reproduction: in vivo and in vitro effects compared

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du Bay, D.T.; Murdy, W.H.

In Lepidium virginicum L., exposure of pollen to 0.6 ppm sulfur dioxide (SO/sub 2/) for 4 h reduced pollen germination in vitro 94% from the control, whereas exposure to 0.6 ppm SO/sub 2/ for 2, 4, and 8 h during flowering reduced pollen germination in vivo 50% from the control, but did not affect seed set. An interaction between SO/sub 2/ and water may have caused the inhibition of pollen germination in a liquid culture medium, as well as on the moist surface of an intact stigma. However, the results suggest that the use of pollen germination and pollen tubemore » elongation in vitro to assess the direct effects of SO/sub 2/ on plant secual reproduction in vivo is not valid.« less

Variation in pollen-donor composition among pollinators in an entomophilous tree species, Castanea crenata, revealed by single-pollen genotyping.

PubMed

Hasegawa, Yoichi; Suyama, Yoshihisa; Seiwa, Kenji

2015-01-01

In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant. We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees. The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances. All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata.

When did C4 Photosynthesis originate: New evidence from δ13C analysis of single grass-pollen grains

NASA Astrophysics Data System (ADS)

Urban, M. A.; Nelson, D. M.; Pearson, A.; Hu, F.

2009-12-01

C4 grasses account for >20% of global primary productivity and dominate tropical, subtropical, and warm-temperate grassland ecosystems. Thus it is vital to understand when and why C4 photosynthesis first evolved in the grass family (Poaceae). However, because of limitations of most proxies, the origin of C4 grasses remains ambiguous. Grass pollen is morphologically indistinct below the family level, making pollen analysis a crude instrument for studying C4-grass evolution. Previous studies have investigated the timing of C4 evolution using molecular tools and δ13C records from n-alkanes, ungulate teeth, and paleosols, but they yield disparate results. Molecular clocks suggest that C4 grasses first evolved between 27 and 36 Ma (million years before present), coincident with the Oligocene decline in pCO2 from >1000 to <500 ppm. In contrast, δ13C-based approaches do not detect the presence of C4 grasses until the middle Miocene, indicating that they were previously uncommon or absent on the landscape. To investigate when C4 photosynthesis first appeared in the grass family, we utilized Single Pollen Isotope Ratio AnaLysis (SPIRAL), a technique that reliably distinguishes C4 from C3 grass pollen via δ13C. We analyzed 837 single grains of grass pollen from eight lacustrine geological samples (~100 grains/sample) from France and Spain spanning the earliest Oligocene to middle Miocene. To distinguish C3/C4 ratios, we used an optimal threshold value of -19.2‰ adjusted for small (~1‰) temporal variations in atmospheric δ13C. Initial results provide unequivocal evidence of C4 grass pollen in all samples (24-57% C4 grass pollen ±9.2% on average) lending further credence to the molecular data, which posits that C4 grasses appeared as early as the Late Eocene, which is a plausible outcome when considering alternate schemes of dating phylogenetic trees. A C4 origin prior to pCO2 reaching its lowest levels of the Cenozoic at the Oligocene/Miocene boundary indicates that ecological or climatic factors played a pivotal role in the evolution of C4 grasses. However, our estimates for the timing of C4 evolution remain imprecise. We do not have SPIRAL data from samples older than ~34 Ma. Future analyzes will include well-dated samples from additional sites as old as the the late Paleocene, when grass pollen first appeared in the fossil record. In addition, we are refining the C3/C4 threshold value using grass pollen from herbarium specimens. New results should help pinpoint the timing of C4 evolution. Comparison of the timing of C4 evolution with independent pCO2, paleoclimate and paleoecological records will be used to assess the factor(s) that drove the evolution and eventual dominance of C4 grasses.

Pollen Competition as a Reproductive Isolation Barrier Represses Transgene Flow between Compatible and Co-Flowering Citrus Genotypes

PubMed Central

Pons, Elsa; Navarro, Antonio; Ollitrault, Patrick; Peña, Leandro

2011-01-01

Background/Objective Despite potential benefits granted by genetically modified (GM) fruit trees, their release and commercialization raises concerns about their potential environmental impact, and the transfer via pollen of transgenes to cross-compatible cultivars is deemed to be the greatest source for environmental exposure. Information compiled from field trials on GM trees is essential to propose measures to minimize the transgene dispersal. We have conducted a field trial of seven consecutive years to investigate the maximum frequency of pollen-mediated crop-to-crop transgene flow in a citrus orchard, and its relation to the genetic, phenological and environmental factors involved. Methodology/Principal Findings Three different citrus genotypes carrying the uidA (GUS) tracer marker gene (pollen donors) and a non-GM self-incompatible contiguous citrus genotype (recipient) were used in conditions allowing natural entomophilous pollination to occur. The examination of 603 to 2990 seeds per year showed unexpectedly low frequencies (0.17–2.86%) of transgene flow. Paternity analyses of the progeny of subsets of recipient plants using 10 microsatellite (SSR) loci demonstrated a higher mating competence of trees from another non-GM pollen source population that greatly limited the mating chance of the contiguous cross-compatible and flowering-synchronized transgenic pollen source. This mating superiority could be explained by a much higher pollen competition capacity of the non-GM genotypes, as was confirmed through mixed-hand pollinations. Conclusions/Significance Pollen competition strongly contributed to transgene confinement. Based on this finding, suitable isolation measures are proposed for the first time to prevent transgene outflow between contiguous plantings of citrus types that may be extendible to other entomophilous transgenic fruit tree species. PMID:21991359

Responses of human birch pollen allergen-reactive T cells to chemically modified allergens (allergoids).

PubMed

Dormann, D; Ebner, C; Jarman, E R; Montermann, E; Kraft, D; Reske-Kunz, A B

1998-11-01

Allergoids are widely used in specific immunotherapy for the treatment of IgE-mediated allergic diseases. The aim of this study was to analyse whether a modification of birch pollen allergens with formaldehyde affects the availability of T-cell epitopes. Efficient modification of the allergens was verified by determining IgE and IgG binding activity using ELISA inhibition tests. T-cell responses to birch pollen allergoids were analysed in polyclonal systems, using peripheral blood mononuclear cells (PBMC) of five birch pollen-allergic individuals, as well as birch pollen extract-reactive T-cell lines (TCL), established from the peripheral blood of 14 birch pollen-allergic donors. To determine whether the modification of natural (n)Bet v 1 with formaldehyde or maleic anhydride results in epitope-specific changes in T-cell reactivities, 22 Bet v 1-specific T-cell clones (TCC), established from nine additional birch pollen-allergic individuals, were tested for their reactivity with these products. The majority of PBMC and TCL showed a reduced response to the birch pollen extract allergoid. Bet v 1-specific TCC could be divided into allergoid-reactive and -non-reactive TCC. No simple correlation between possible modification sites of formaldehyde in the respective T-cell epitopes and the stimulatory potential of the allergoid was observed. Mechanisms of suppression or of anergy induction were excluded as an explanation for the non-reactivity of representative TCC. All TCC could be stimulated by maleylated and unmodified nBet v 1 to a similar extent. These results demonstrate differences in the availability of T-cell epitopes between allergoids and unmodified allergens, which are most likely due to structural changes within the allergen molecule.

Heteranthery as a solution to the demand for pollen as food and for pollination - Legitimate flower visitors reject flowers without feeding anthers.

PubMed

Mesquita-Neto, J N; Costa, B K P; Schlindwein, C

2017-11-01

Heteranthery, the presence of feeding and pollinating anthers in the same flower, seems to mediate the evolutionary dilemma for plants to protect their gametes and yet provide food for pollinators. This study aims to elucidate the role of heteranthery in the buzz-pollinated Senna reniformis. The fecundity of pollen from long-, medium- and short-sized anthers was determined by hand cross-pollination experiments, and the quantity, size, ornamentation and viability of pollen of different anthers were compared. Rates of flower rejection by bees were measured in anther removal experiments to assess the preferences of flower visitors for feeding or pollinating anthers. Large bees, which were the effective pollinators of self-incompatible S. reniformis, avoided flowers without short feeding anthers, but not those without medium or long anthers. Illegitimate small and medium-sized bees were unresponsive to anther exclusion experiments. Long anthers deposited pollen on the back and short anthers on the venter of large bees. Pollen from long anthers had higher in vitro viability and higher fruit and seed set after cross-pollination than pollen from other sized anthers. Short anthers produce feeding pollen to effective pollinators and long anthers are related to pollination of S. reniformis. Bee behaviour and size was found to directly influence the role of anthers in the 'division of labour'. Only large bee pollinators that carry the pollinating pollen from long anthers in 'safe sites' associated short anthers with the presence of food. In the absence of these larger bee pollinators, the role of heteranthery in S. reniformis would be strongly compromised and its function would be lost. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Transporters involved in pH and K + homeostasis affect pollen wall formation, male fertility, and embryo development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padmanaban, Senthilkumar; Czerny, Daniel D.; Levin, Kara A.

Flowering plant genomes encode multiple cation/H + exchangers (CHXs) whose functions are largely unknown. AtCHX17, AtCHX18, and AtCHX19 are membrane transporters that modulate K+ and pH homeostasis and are localized in the dynamic endomembrane system. Loss of function reduced seed set, but the particular phase(s) of reproduction affected was not determined. Pollen tube growth and ovule targeting of chx17chx18chx19 mutant pollen appeared normal, but reciprocal cross experiments indicate a largely male defect. Although triple mutant pollen tubes reach ovules of a wild-type pistil and a synergid cell degenerated, half of those ovules were unfertilized or showed fertilization of the eggmore » or central cell, but not both female gametes. Fertility could be partially compromised by impaired pollen tube and/or sperm function as CHX19 and CHX18 are expressed in the pollen tube and sperm cell, respectively. When fertilization was successful in self-pollinated mutants, early embryo formation was retarded compared with embryos from wild-type ovules receiving mutant pollen. Thus CHX17 and CHX18 proteins may promote embryo development possibly through the endosperm where these genes are expressed. The reticulate pattern of the pollen wall was disorganized in triple mutants, indicating perturbation of wall formation during male gametophyte development. Lastly, as pH and cation homeostasis mediated by AtCHX17 affect membrane trafficking and cargo delivery, these results suggest that male fertility, sperm function, and embryo development are dependent on proper cargo sorting and secretion that remodel cell walls, plasma membranes, and extracellular factors.« less

Pollen competition as a reproductive isolation barrier represses transgene flow between compatible and co-flowering citrus genotypes.

PubMed

Pons, Elsa; Navarro, Antonio; Ollitrault, Patrick; Peña, Leandro

2011-01-01

Despite potential benefits granted by genetically modified (GM) fruit trees, their release and commercialization raises concerns about their potential environmental impact, and the transfer via pollen of transgenes to cross-compatible cultivars is deemed to be the greatest source for environmental exposure. Information compiled from field trials on GM trees is essential to propose measures to minimize the transgene dispersal. We have conducted a field trial of seven consecutive years to investigate the maximum frequency of pollen-mediated crop-to-crop transgene flow in a citrus orchard, and its relation to the genetic, phenological and environmental factors involved. Three different citrus genotypes carrying the uidA (GUS) tracer marker gene (pollen donors) and a non-GM self-incompatible contiguous citrus genotype (recipient) were used in conditions allowing natural entomophilous pollination to occur. The examination of 603 to 2990 seeds per year showed unexpectedly low frequencies (0.17-2.86%) of transgene flow. Paternity analyses of the progeny of subsets of recipient plants using 10 microsatellite (SSR) loci demonstrated a higher mating competence of trees from another non-GM pollen source population that greatly limited the mating chance of the contiguous cross-compatible and flowering-synchronized transgenic pollen source. This mating superiority could be explained by a much higher pollen competition capacity of the non-GM genotypes, as was confirmed through mixed-hand pollinations. Pollen competition strongly contributed to transgene confinement. Based on this finding, suitable isolation measures are proposed for the first time to prevent transgene outflow between contiguous plantings of citrus types that may be extendible to other entomophilous transgenic fruit tree species.

Transporters involved in pH and K + homeostasis affect pollen wall formation, male fertility, and embryo development

DOE PAGES

Padmanaban, Senthilkumar; Czerny, Daniel D.; Levin, Kara A.; ...

2017-02-23

Flowering plant genomes encode multiple cation/H + exchangers (CHXs) whose functions are largely unknown. AtCHX17, AtCHX18, and AtCHX19 are membrane transporters that modulate K+ and pH homeostasis and are localized in the dynamic endomembrane system. Loss of function reduced seed set, but the particular phase(s) of reproduction affected was not determined. Pollen tube growth and ovule targeting of chx17chx18chx19 mutant pollen appeared normal, but reciprocal cross experiments indicate a largely male defect. Although triple mutant pollen tubes reach ovules of a wild-type pistil and a synergid cell degenerated, half of those ovules were unfertilized or showed fertilization of the eggmore » or central cell, but not both female gametes. Fertility could be partially compromised by impaired pollen tube and/or sperm function as CHX19 and CHX18 are expressed in the pollen tube and sperm cell, respectively. When fertilization was successful in self-pollinated mutants, early embryo formation was retarded compared with embryos from wild-type ovules receiving mutant pollen. Thus CHX17 and CHX18 proteins may promote embryo development possibly through the endosperm where these genes are expressed. The reticulate pattern of the pollen wall was disorganized in triple mutants, indicating perturbation of wall formation during male gametophyte development. Lastly, as pH and cation homeostasis mediated by AtCHX17 affect membrane trafficking and cargo delivery, these results suggest that male fertility, sperm function, and embryo development are dependent on proper cargo sorting and secretion that remodel cell walls, plasma membranes, and extracellular factors.« less

Isolation and characterization of a novel pollen-specific promoter in maize (Zea mays L.).

PubMed

Wang, He; Fan, Mingxia; Wang, Guohong; Zhang, Chunyu; Shi, Lei; Wei, Zhengyi; Ma, Wenjuan; Chang, Jing; Huang, Senxin; Lin, Feng

2017-06-01

ZmSTK2_USP, located on the long arm of chromosome 4, belongs to the serine/threonine kinase gene in maize. The sequence analysis of 2100 bp upstream from the start codon ATG has shown that it contains cis-element motifs and two types of anther/pollen-specific promoter elements (GTGA and AGAAA), suggesting that it is the pollen-specific promoter. To investigate the function of ZmSTK2_USP promoter, the GUS gene fusion system was employed. In proZmSTK2_USP-GUS genetically modified plants, GUS activity was detected in mature pollen grains and pollen tubes but not found in other floral and vegetative tissues. These results show that proZmSTK2_USP is the pollen-specific promoter and drives pollen-specific activity during the middle stage of pollen development until pollen maturation.

Hepatoprotective Potential of Chestnut Bee Pollen on Carbon Tetrachloride-Induced Hepatic Damages in Rats

PubMed Central

Yıldız, Oktay; Can, Zehra; Saral, Özlem; Yuluğ, Esin; Öztürk, Ferhat; Aliyazıcıoğlu, Rezzan; Canpolat, Sinan; Kolaylı, Sevgi

2013-01-01

Bee pollen has been used as an apitherapy agent for several centuries to treat burns, wounds, gastrointestinal disorders, and various other diseases. The aim of our study was to investigate the hepatoprotective effects of chestnut bee pollen against carbon tetrachloride (CCI4)-induced liver damage. Total phenolic content, flavonoid, ferric reducing/antioxidant power, and DPPH radical activity measurements were used as antioxidant capacity determinants of the pollen. The study was conducted in rats as seven groups. Two different concentrations of chestnut bee pollens (200 and 400 mg/kg/day) were given orally and one group was administered with silibinin (50 mg/kg/day, i.p.) for seven days to the rats following the CCI4 treatment. The protective effect of the bee pollen was monitored by aspartate transaminase (AST) and alanine transaminase (AST) activities, histopathological imaging, and antioxidant parameters from the blood and liver samples of the rats. The results were compared with the silibinin-treated and untreated groups. We detected that CCI4 treatment induced liver damage and both the bee pollen and silibinin-treated groups reversed the damage; however, silibinin caused significant weight loss and mortality due, severe diarrhea in the rats. The chestnut pollen had showed 28.87 mg GAE/g DW of total phenolic substance, 8.07 mg QUE/g DW of total flavonoid, 92.71 mg Cyn-3-glu/kg DW of total anthocyanins, and 9 mg β-carotene/100 g DW of total carotenoid and substantial amount of antioxidant power according to FRAP and DPPH activity. The results demonstrated that the chestnut bee pollen protects the hepatocytes from the oxidative stress and promotes the healing of the liver damage induced by CCI4 toxicity. Our findings suggest that chestnut bee pollen can be used as a safe alternative to the silibinin in the treatment of liver injuries. PMID:24250716

Stable Carbon Isotope Ratios of Individual Pollen Grains as a Proxy for C3- Versus C4-Grass Abundance in Paleorecords: A Validation Study

NASA Astrophysics Data System (ADS)

Nelson, D. M.; Hu, F.; Pearson, A.

2007-12-01

C3 and C4 grasses have distinct influences on major biogeochemical processes and unique responses to important environmental controls. Difficulties in distinguishing between these two functional groups of grasses have hindered paleoecological studies of grass-dominated ecosystems. We recently developed a technique to analyze the stable carbon isotope composition of individual grass-pollen grains using a spooling- wire microcombustion device interfaced with an isotope-ratio mass spectrometer (Nelson et al. 2007). This technique holds promise for improving C3 and C4 grass reconstructions. It requires ~90% fewer grains than typical methods and avoids assumptions associated with mixing models. However, our previous work was based on known C3 and C4 grasses from herbarium specimens and field collections and the technique had not been test using geological samples. To test the ability of this technique to reproduce the abundance of C3 and C4 grasses on the landscape, we measured δ13C values of >1500 individual grains of grass pollen isolated from the surface sediments of 10 North American lakes that span a large gradient of C3 and C4 grass abundance. Results indicate a strong positive correlation (r=0.94) between % C4-grass pollen (derived from classifying δ13C values from single grains as C3 and C4) and the literature-reported abundance of C4 grasses on the landscape. However, the measured % C4-grass pollen shows some deviation from the actual abundance at sites with high proportions of C4 grasses. This is likely caused by uncertainty in the magnitude, composition, and variability of the analytical blank associated with these measurements. Correcting for this deviation using regression analysis improves the estimation of the abundance of C4 grasses on the landscape. Comparison of the % C4-grass pollen with C/N and δ13C measurements of total organic matter in the same lake-sediment samples illustrates the distinct advantage of grass-pollen δ13C as a proxy for distinguishing C3 and C4 shifts. At 9 of the 10 sites C/N values indicate that surface-sediment organic matter was derived primarily from aquatic production. At the one site where organic matter was produced primarily by vascular plants the δ13C value (-29.3°) suggests organic matter derived exclusively from C3 plants. However, ~80% of the grasses on the landscape at this site are C4 grasses. The C3- like bulk-sediment δ13C value likely represents woody species, which comprise >90% of the pollen spectra. Thus δ13C analysis of single grains of grass pollen offers a new tool to classify grass pollen into two major functional groups and promises to advance our understanding of grassland ecology and evolution. Reference Nelson, D.M., Hu, F.S., Mikucki, J., Tian, J., and Pearson, A., 2007, Carbon isotopic analysis of individual pollen grains from C3 and C4 grasses using a spooling wire microcombustion interface: Geochimica et Cosmochimica Acta, v. 71, p. 4005-4014.

Impatiens pollen germination and tube growth as a bioassay for toxic substances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bliderback, D.E.

Pollen of Impatiens sultanii Hook F. germinates and forms tubes rapidly at 25/sup 0/C in a simple medium containing 111.0 ppm CaCl/sub 2/, 13.6 ppm KH/sub 2/PO/sub 4/, and 1000 ppm boric acid. Calcium, potassium, and boron are essential for germination and tube growth, but sucrose is not required. Pollen tubes grow with equal rapidity in liquid medium or on a medium solidified with 1% agar. Tube growth rates are linear for 1 hr. When different pollen sources or clonal sources are utilized, no variation in pollen tube growth is observed, and pollen from individual flowers remain viable for 26more » hr. Formaldehyde inhibits pollen germination, tube production, and tube lengths at 7.5-10 ppm. With 2,4-dichlorophenol, pollen germination and tube production is inhibited at 0.5-20 ppm, while tube growth is inhibited significantly at 25 ppm. A biphasic inhibition of germination and tube formation occurs with p-cresol with a low level of inhibition occurring at 40-60 ppm and a higher one at 100-125 ppm. Tube lengths were inhibited at 150 ppm p-cresol. Acrylamide and dioctyl phthalate have no measurable effect upon pollen germination and tube growth.« less

Variation in Pollen-Donor Composition among Pollinators in an Entomophilous Tree Species, Castanea crenata, Revealed by Single-Pollen Genotyping

PubMed Central

Hasegawa, Yoichi; Suyama, Yoshihisa; Seiwa, Kenji

2015-01-01

Background In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant. Methods We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees. Results The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances. Conclusions All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata. PMID:25793619

Does the increase in ambient CO2 concentration elevate allergy risks posed by oak pollen?

NASA Astrophysics Data System (ADS)

Kim, Kyu Rang; Oh, Jae-Won; Woo, Su-Young; Seo, Yun Am; Choi, Young-Jin; Kim, Hyun Seok; Lee, Wi Young; Kim, Baek-Jo

2018-05-01

Oak pollen is a major respiratory allergen in Korea, and the distribution of oak trees is expected to increase by ecological succession and climate change. One of the drivers of climate change is increasing CO2, which is also known to amplify the allergy risk of weed pollen by inducing elevated allergenic protein content. However, the impact of CO2 concentration on tree pollen is not clearly understood due to the experimental difficulties in carrying out extended CO2 treatment. To study the response of pollen production of sawtooth oak trees (Quercus acutissima) to elevated levels of ambient CO2, three open-top chambers at the National Institute of Forest Science in Suwon, Korea were utilized with daytime (8 am-6 pm) CO2 concentrations of ambient (× 1.0, 400 ppm), × 1.4 ( 560 ppm), and × 1.8 ( 720 ppm) treatments. Each chamber had three sawtooth oak trees planted in September 2009. One or two trees per chamber matured to bloom in 2016. Five to six catkins were selected per tree and polyethylene bags were attached to collect pollen grains. The total number of catkins per tree was counted and the number and weight of pollen grains per catkin were measured. Oak allergen—Que a 1 (Allergon Co., Uppsala, Sweden)—was extracted and purified to make an ELISA kit by which the antigen levels in the pollen samples were quantified. Total pollen counts per tree of the × 1.4 and × 1.8 treatments showed significant increase of 353 and 1299%, respectively, from the × 1.0 treatment (p < 0.001). Allergenic protein contents at the × 1.4 and × 1.8 treatments also showed significant increase of 12 and 11%, respectively (p = 0.011). The × 1.8 treatment induced significant difference from the × 1.0 treatment in terms of pollen production and allergenic protein content, whereas the × 1.4 treatment showed mixed significance. In summary, the oak trees under the elevated CO2 levels, which are expected in the changing climate, produced significantly higher amount of pollen and allergenic protein than under the present air conditions.

Male Sterile2 Encodes a Plastid-Localized Fatty Acyl Carrier Protein Reductase Required for Pollen Exine Development in Arabidopsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, W.; Shanklin, J.; Yu, X.-H.

Male Sterile2 (MS2) is predicted to encode a fatty acid reductase required for pollen wall development in Arabidopsis (Arabidopsis thaliana). Transient expression of MS2 in tobacco (Nicotiana benthamiana) leaves resulted in the accumulation of significant levels of C16 and C18 fatty alcohols. Expression of MS2 fused with green fluorescent protein revealed that an amino-terminal transit peptide targets the MS2 to plastids. The plastidial localization of MS2 is biologically important because genetic complementation of MS2 in ms2 homozygous plants was dependent on the presence of its amino-terminal transit peptide or that of the Rubisco small subunit protein amino-terminal transit peptide. Inmore » addition, two domains, NAD(P)H-binding domain and sterile domain, conserved in MS2 and its homologs were also shown to be essential for MS2 function in pollen exine development by genetic complementation testing. Direct biochemical analysis revealed that purified recombinant MS2 enzyme is able to convert palmitoyl-Acyl Carrier Protein to the corresponding C16:0 alcohol with NAD(P)H as the preferred electron donor. Using optimized reaction conditions (i.e. at pH 6.0 and 30 C), MS2 exhibits a K{sub m} for 16:0-Acyl Carrier Protein of 23.3 {+-} 4.0 {mu}m, a V{sub max} of 38.3 {+-} 4.5 nmol mg{sup -1} min{sup -1}, and a catalytic efficiency/K{sub m} of 1,873 m{sup -1} s{sup -1}. Based on the high homology of MS2 to other characterized fatty acid reductases, it was surprising that MS2 showed no activity against palmitoyl- or other acyl-coenzyme A; however, this is consistent with its plastidial localization. In summary, genetic and biochemical evidence demonstrate an MS2-mediated conserved plastidial pathway for the production of fatty alcohols that are essential for pollen wall biosynthesis in Arabidopsis.« less

Gene flow in genetically modified wheat.

PubMed

Rieben, Silvan; Kalinina, Olena; Schmid, Bernhard; Zeller, Simon L

2011-01-01

Understanding gene flow in genetically modified (GM) crops is critical to answering questions regarding risk-assessment and the coexistence of GM and non-GM crops. In two field experiments, we tested whether rates of cross-pollination differed between GM and non-GM lines of the predominantly self-pollinating wheat Triticum aestivum. In the first experiment, outcrossing was studied within the field by planting "phytometers" of one line into stands of another line. In the second experiment, outcrossing was studied over distances of 0.5-2.5 m from a central patch of pollen donors to adjacent patches of pollen recipients. Cross-pollination and outcrossing was detected when offspring of a pollen recipient without a particular transgene contained this transgene in heterozygous condition. The GM lines had been produced from the varieties Bobwhite or Frisal and contained Pm3b or chitinase/glucanase transgenes, respectively, in homozygous condition. These transgenes increase plant resistance against pathogenic fungi. Although the overall outcrossing rate in the first experiment was only 3.4%, Bobwhite GM lines containing the Pm3b transgene were six times more likely than non-GM control lines to produce outcrossed offspring. There was additional variation in outcrossing rate among the four GM-lines, presumably due to the different transgene insertion events. Among the pollen donors, the Frisal GM line expressing a chitinase transgene caused more outcrossing than the GM line expressing both a chitinase and a glucanase transgene. In the second experiment, outcrossing after cross-pollination declined from 0.7-0.03% over the test distances of 0.5-2.5 m. Our results suggest that pollen-mediated gene flow between GM and non-GM wheat might only be a concern if it occurs within fields, e.g. due to seed contamination. Methodologically our study demonstrates that outcrossing rates between transgenic and other lines within crops can be assessed using a phytometer approach and that gene-flow distances can be efficiently estimated with population-level PCR analyses. © 2011 Rieben et al.

Gene Flow in Genetically Modified Wheat

PubMed Central

Rieben, Silvan; Kalinina, Olena; Schmid, Bernhard; Zeller, Simon L.

2011-01-01

Understanding gene flow in genetically modified (GM) crops is critical to answering questions regarding risk-assessment and the coexistence of GM and non-GM crops. In two field experiments, we tested whether rates of cross-pollination differed between GM and non-GM lines of the predominantly self-pollinating wheat Triticum aestivum. In the first experiment, outcrossing was studied within the field by planting “phytometers” of one line into stands of another line. In the second experiment, outcrossing was studied over distances of 0.5–2.5 m from a central patch of pollen donors to adjacent patches of pollen recipients. Cross-pollination and outcrossing was detected when offspring of a pollen recipient without a particular transgene contained this transgene in heterozygous condition. The GM lines had been produced from the varieties Bobwhite or Frisal and contained Pm3b or chitinase/glucanase transgenes, respectively, in homozygous condition. These transgenes increase plant resistance against pathogenic fungi. Although the overall outcrossing rate in the first experiment was only 3.4%, Bobwhite GM lines containing the Pm3b transgene were six times more likely than non-GM control lines to produce outcrossed offspring. There was additional variation in outcrossing rate among the four GM-lines, presumably due to the different transgene insertion events. Among the pollen donors, the Frisal GM line expressing a chitinase transgene caused more outcrossing than the GM line expressing both a chitinase and a glucanase transgene. In the second experiment, outcrossing after cross-pollination declined from 0.7–0.03% over the test distances of 0.5–2.5 m. Our results suggest that pollen-mediated gene flow between GM and non-GM wheat might only be a concern if it occurs within fields, e.g. due to seed contamination. Methodologically our study demonstrates that outcrossing rates between transgenic and other lines within crops can be assessed using a phytometer approach and that gene-flow distances can be efficiently estimated with population-level PCR analyses. PMID:22216349

Novel allergic asthma model demonstrates ST2-dependent dendritic cell targeting by cypress pollen.

PubMed

Gabriele, Lucia; Schiavoni, Giovanna; Mattei, Fabrizio; Sanchez, Massimo; Sestili, Paola; Butteroni, Cinzia; Businaro, Rita; Mirchandani, Ananda; Niedbala, Wanda; Liew, Foo Y; Afferni, Claudia

2013-09-01

Cypress pollen causes respiratory syndromes with different grades of severity, including asthma. IL-33, its receptor ST2, and dendritic cells (DCs) have been implicated in human respiratory allergy. We sought to define a new mouse model of allergy to cypress pollen that recapitulates clinical parameters in allergic patients and to evaluate the implications of DCs and the IL-33/ST2 pathway in this pathology. BALB/c mice, either wild-type or ST2 deficient (ST2(-/-)), were sensitized and challenged with the Cupressus arizonica major allergen nCup a 1. Local and systemic allergic responses were evaluated. Pulmonary cells were characterized by means of flow cytometry. DCs were stimulated with nCup a 1 and tested for their biological response to IL-33 in coculture assays. nCup a 1 causes a respiratory syndrome closely resembling human pollinosis in BALB/c mice. nCup a 1-treated mice exhibit the hallmarks of allergic pathology associated with pulmonary infiltration of eosinophils, T cells, and DCs and a dominant TH2-type immune response. IL-33 levels were increased in lungs and sera of nCup a 1-treated mice and in subjects with cypress allergy. The allergen-specific reaction was markedly reduced in ST2(-/-) mice, which showed fewer infiltrating eosinophils, T cells, and DCs in the lungs. Finally, stimulation of DCs with nCup a 1 resulted in ST2 upregulation that endowed DCs with increased ability to respond to IL-33-mediated differentiation of IL-5- and IL-13-producing CD4 T cells. Our findings define a novel preclinical model of allergy to cypress pollen and provide the first evidence of a functionally relevant linkage between pollen allergens and TH2-polarizing activity by DCs through IL-33/ST2. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Identification of the self-incompatibility locus F-box protein-containing complex in Petunia inflata.

PubMed

Li, Shu; Sun, Penglin; Williams, Justin Stephen; Kao, Teh-hui

2014-03-01

The polymorphic S-locus regulating self-incompatibility (SI) in Petunia contains the S-RNase gene and a number of S-locus F-box (SLF) genes. While penetrating the style through the stigma, a pollen tube takes up all S-RNases, but only self S-RNase inhibits pollen tube growth. Recent evidence suggests that SLFs produced by pollen collectively interact with and detoxify non-self S-RNases, but none can interact with self S-RNase. An SLF may be the F-box protein component of an SCF complex (containing Cullin1, Skp1 and Rbx1), which mediates ubiquitination of protein substrates for degradation by the 26S proteasome. However, the precise nature of the complex is unknown. We used pollen extracts of a transgenic plant over-expressing GFP-fused S2-SLF1 (SLF1 of S 2-haplotype) for co-immunoprecipitation (Co-IP) followed by mass spectrometry (MS). We identified PiCUL1-P (a pollen-specific Cullin1), PiSSK1 (a pollen-specific Skp1-like protein) and PiRBX1 (an Rbx1). To validate the results, we raised transgenic plants over-expressing PiSSK1:FLAG:GFP and used pollen extracts for Co-IP-MS. The results confirmed the presence of PiCUL1-P and PiRBX1 in the complex and identified two different SLFs as the F-box protein component. Thus, all but Rbx1 of the complex may have evolved in SI, and all SLFs may be the F-box component of similar complexes.

Transcriptional Evidence for Inferred Pattern of Pollen Tube-Stigma Metabolic Coupling during Pollination

PubMed Central

Wang, Fang; Dong, YuXiu; Li, XingGuo; Zhang, Xian Sheng

2014-01-01

It is difficult to derive all qualitative proteomic and metabolomic experimental data in male (pollen tube) and female (pistil) reproductive tissues during pollination because of the limited sensitivity of current technology. In this study, genome-scale enzyme correlation network models for plants (Arabidopsis/maize) were constructed by analyzing the enzymes and metabolic routes from a global perspective. Then, we developed a data-driven computational pipeline using the “guilt by association” principle to analyze the transcriptional coexpression profiles of enzymatic genes in the consecutive steps for metabolic routes in the fast-growing pollen tube and stigma during pollination. The analysis identified an inferred pattern of pollen tube-stigma ethanol coupling. When the pollen tube elongates in the transmitting tissue (TT) of the pistil, this elongation triggers the mobilization of energy from glycolysis in the TT cells of the pistil. Energy-rich metabolites (ethanol) are secreted that can be taken up by the pollen tube, where these metabolites are incorporated into the pollen tube's tricarboxylic acid (TCA) cycle, which leads to enhanced ATP production for facilitating pollen tube growth. In addition, our analysis also provided evidence for the cooperation of kaempferol, dTDP-alpha-L-rhamnose and cell-wall-related proteins; phosphatidic-acid-mediated Ca2+ oscillations and cytoskeleton; and glutamate degradation IV for γ-aminobutyric acid (GABA) signaling activation in Arabidopsis and maize stigmas to provide the signals and materials required for pollen tube tip growth. In particular, the “guilt by association” computational pipeline and the genome-scale enzyme correlation network models (GECN) developed in this study was initiated with experimental “omics” data, followed by data analysis and data integration to determine correlations, and could provide a new platform to assist inachieving a deeper understanding of the co-regulation and inter-regulation model in plant research. PMID:25215523

Pollinator-mediated interactions in experimental arrays vary with neighbor identity.

PubMed

Ha, Melissa K; Ivey, Christopher T

2017-02-01

Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C. biloba neighbors, noncongeneric neighbors, additional conspecific plants, or no additional plants as a density control. We compared whole-plant pollen limitation of seed set, pollinator behavior, and pollen deposition among treatments. Interactions mediated by shared pollinators depended on the identity of the neighbor and possibly changed through time, although flowering-season comparisons were compromised by low early-season plant survival. Interactions with conspecific neighbors were likely competitive late in the season. Interactions with C. biloba appeared to involve facilitation or neutral interactions. Interactions with noncongeners were more consistently competitive. The community composition of pollinators varied among treatment combinations. Pollinator-mediated interactions involved competition and likely facilitation, depending on coflowering neighbor. Experimental manipulation helped to reveal context-dependent variation in indirect biotic interactions. © 2017 Botanical Society of America.

Ragweed pollen production and dispersion modelling within a regional climate system, calibration and application over Europe

NASA Astrophysics Data System (ADS)

Liu, Li; Solmon, Fabien; Vautard, Robert; Hamaoui-Laguel, Lynda; Zsolt Torma, Csaba; Giorgi, Filippo

2016-05-01

Common ragweed (Ambrosia artemisiifolia L.) is a highly allergenic and invasive plant in Europe. Its pollen can be transported over large distances and has been recognized as a significant cause of hay fever and asthma (D'Amato et al., 2007; Burbach et al., 2009). To simulate production and dispersion of common ragweed pollen, we implement a pollen emission and transport module in the Regional Climate Model (RegCM) version 4 using the framework of the Community Land Model (CLM) version 4.5. In this online approach pollen emissions are calculated based on the modelling of plant distribution, pollen production, species-specific phenology, flowering probability, and flux response to meteorological conditions. A pollen tracer model is used to describe pollen advective transport, turbulent mixing, dry and wet deposition. The model is then applied and evaluated on a European domain for the period 2000-2010. To reduce the large uncertainties notably due to the lack of information on ragweed density distribution, a calibration based on airborne pollen observations is used. Accordingly a cross validation is conducted and shows reasonable error and sensitivity of the calibration. Resulting simulations show that the model captures the gross features of the pollen concentrations found in Europe, and reproduce reasonably both the spatial and temporal patterns of flowering season and associated pollen concentrations measured over Europe. The model can explain 68.6, 39.2, and 34.3 % of the observed variance in starting, central, and ending dates of the pollen season with associated root mean square error (RMSE) equal to 4.7, 3.9, and 7.0 days, respectively. The correlation between simulated and observed daily concentrations time series reaches 0.69. Statistical scores show that the model performs better over the central Europe source region where pollen loads are larger and the model is better constrained. From these simulations health risks associated to common ragweed pollen spread are evaluated through calculation of exposure time above health-relevant threshold levels. The total risk area with concentration above 5 grains m-3 takes up 29.5 % of domain. The longest exposure time occurs on Pannonian Plain, where the number of days per year with the daily concentration above 20 grains m-3 exceeds 30.

Urbanity as a determinant of exposure to grass pollen in Helsinki Metropolitan area, Finland.

PubMed

Hugg, Timo T; Hjort, Jan; Antikainen, Harri; Rusanen, Jarmo; Tuokila, Mirkka; Korkonen, Sanna; Weckström, Jan; Jaakkola, Maritta S; Jaakkola, Jouni J K

2017-01-01

Little is known about the levels of exposure to grass pollen in urban environments. We assessed the spatio-temporal variation of grass pollen concentrations and the role of urbanity as a determinant of grass pollen exposure in the Helsinki Metropolitan area. We monitored grass pollen concentrations in 2013 at 16 sites during the peak pollen season by using rotorod-type samplers at the breathing height. The sites were in the cities of Helsinki and Espoo, Finland, and formed city-specific lines that represented urban-rural gradient. The monitoring sites were both visually and based on land use data ranked as high to low (graded 1 to 8) pollen area. The lowest grass pollen concentrations were observed in the most urban sites compared to the least urban sites (mean 3.6 vs. 6.8 grains/m3 in Helsinki; P<0.0001, and 5.2 vs. 87.5 grains/m3 in Espoo; P<0.0001). Significant differences were observed between concentrations measured in morning periods compared to afternoon periods (4.9 vs. 5.4 in Helsinki, P = 0.0186, and 21.8 vs. 67.1 in Espoo, P = 0.0004). The mean pollen concentration increased with decreasing urbanity both in Helsinki (0.59 grains/m3 per urbanity rank, 95% CI 0.25-0.93) and Espoo (8.42, 6.23-10.61). Pollen concentrations were highest in the afternoons and they were related to the ambient temperature. Urbanity was a strong and significant determinant of pollen exposure in two Finnish cities. Pollen exposure can periodically reach such high levels even in the most urban environments that can cause allergic reactions among individuals with allergies.

Urbanity as a determinant of exposure to grass pollen in Helsinki Metropolitan area, Finland

PubMed Central

Hugg, Timo T.; Hjort, Jan; Antikainen, Harri; Rusanen, Jarmo; Tuokila, Mirkka; Korkonen, Sanna; Weckström, Jan; Jaakkola, Maritta S.

2017-01-01

Little is known about the levels of exposure to grass pollen in urban environments. We assessed the spatio-temporal variation of grass pollen concentrations and the role of urbanity as a determinant of grass pollen exposure in the Helsinki Metropolitan area. We monitored grass pollen concentrations in 2013 at 16 sites during the peak pollen season by using rotorod-type samplers at the breathing height. The sites were in the cities of Helsinki and Espoo, Finland, and formed city-specific lines that represented urban-rural gradient. The monitoring sites were both visually and based on land use data ranked as high to low (graded 1 to 8) pollen area. The lowest grass pollen concentrations were observed in the most urban sites compared to the least urban sites (mean 3.6 vs. 6.8 grains/m3 in Helsinki; P<0.0001, and 5.2 vs. 87.5 grains/m3 in Espoo; P<0.0001). Significant differences were observed between concentrations measured in morning periods compared to afternoon periods (4.9 vs. 5.4 in Helsinki, P = 0.0186, and 21.8 vs. 67.1 in Espoo, P = 0.0004). The mean pollen concentration increased with decreasing urbanity both in Helsinki (0.59 grains/m3 per urbanity rank, 95% CI 0.25–0.93) and Espoo (8.42, 6.23–10.61). Pollen concentrations were highest in the afternoons and they were related to the ambient temperature. Urbanity was a strong and significant determinant of pollen exposure in two Finnish cities. Pollen exposure can periodically reach such high levels even in the most urban environments that can cause allergic reactions among individuals with allergies. PMID:29023565

Evaluation of Pollen Apps Forecasts: The Need for Quality Control in an eHealth Service.

PubMed

Bastl, Katharina; Berger, Uwe; Kmenta, Maximilian

2017-05-08

Pollen forecasts are highly valuable for allergen avoidance and thus raising the quality of life of persons concerned by pollen allergies. They are considered as valuable free services for the public. Careful scientific evaluation of pollen forecasts in terms of accurateness and reliability has not been available till date. The aim of this study was to analyze 9 mobile apps, which deliver pollen information and pollen forecasts, with a focus on their accurateness regarding the prediction of the pollen load in the grass pollen season 2016 to assess their usefulness for pollen allergy sufferers. The following number of apps was evaluated for each location: 3 apps for Vienna (Austria), 4 apps for Berlin (Germany), and 1 app each for Basel (Switzerland) and London (United Kingdom). All mobile apps were freely available. Today's grass pollen forecast was compared throughout the defined grass pollen season at each respective location with measured grass pollen concentrations. Hit rates were calculated for the exact performance and for a tolerance in a range of ±2 and ±4 pollen per cubic meter. In general, for most apps, hit rates score around 50% (6 apps). It was found that 1 app showed better results, whereas 3 apps performed less well. Hit rates increased when calculated with tolerances for most apps. In contrast, the forecast for the "readiness to flower" for grasses was performed at a sufficiently accurate level, although only two apps provided such a forecast. The last of those forecasts coincided with the first moderate grass pollen load on the predicted day or 3 days after and performed even from about a month before well within the range of 3 days. Advertisement was present in 3 of the 9 analyzed apps, whereas an imprint mentioning institutions with experience in pollen forecasting was present in only three other apps. The quality of pollen forecasts is in need of improvement, and quality control for pollen forecasts is recommended to avoid potential harm to pollen allergy sufferers due to inadequate forecasts. The inclusion of information on reliability of provided forecasts and a similar handling regarding probabilistic weather forecasts should be considered. ©Katharina Bastl, Uwe Berger, Maximilian Kmenta. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 08.05.2017.

Evaluation of Pollen Apps Forecasts: The Need for Quality Control in an eHealth Service

PubMed Central

Berger, Uwe; Kmenta, Maximilian

2017-01-01

Background Pollen forecasts are highly valuable for allergen avoidance and thus raising the quality of life of persons concerned by pollen allergies. They are considered as valuable free services for the public. Careful scientific evaluation of pollen forecasts in terms of accurateness and reliability has not been available till date. Objective The aim of this study was to analyze 9 mobile apps, which deliver pollen information and pollen forecasts, with a focus on their accurateness regarding the prediction of the pollen load in the grass pollen season 2016 to assess their usefulness for pollen allergy sufferers. Methods The following number of apps was evaluated for each location: 3 apps for Vienna (Austria), 4 apps for Berlin (Germany), and 1 app each for Basel (Switzerland) and London (United Kingdom). All mobile apps were freely available. Today’s grass pollen forecast was compared throughout the defined grass pollen season at each respective location with measured grass pollen concentrations. Hit rates were calculated for the exact performance and for a tolerance in a range of ±2 and ±4 pollen per cubic meter. Results In general, for most apps, hit rates score around 50% (6 apps). It was found that 1 app showed better results, whereas 3 apps performed less well. Hit rates increased when calculated with tolerances for most apps. In contrast, the forecast for the “readiness to flower” for grasses was performed at a sufficiently accurate level, although only two apps provided such a forecast. The last of those forecasts coincided with the first moderate grass pollen load on the predicted day or 3 days after and performed even from about a month before well within the range of 3 days. Advertisement was present in 3 of the 9 analyzed apps, whereas an imprint mentioning institutions with experience in pollen forecasting was present in only three other apps. Conclusions The quality of pollen forecasts is in need of improvement, and quality control for pollen forecasts is recommended to avoid potential harm to pollen allergy sufferers due to inadequate forecasts. The inclusion of information on reliability of provided forecasts and a similar handling regarding probabilistic weather forecasts should be considered. PMID:28483740

Allergenic pollen pollinosis in Madrid.

PubMed

Subiza, J; Jerez, M; Jiménez, J A; Narganes, M J; Cabrera, M; Varela, S; Subiza, E

1995-07-01

A 15-year pollen count was performed in the atmosphere of Madrid, Spain, to determine the months in which the highest concentrations of allergenic pollens occur. Pollen counts were done with a Burkard spore trap (Burkard Manufacturing, Rickmansworth, Herst., U.K.). The results were subsequently compared with results of skin tests in patients with pollinosis born and living in and around Madrid. The highest airborne presence (percent of total yearly pollen counts, mean of counts from 1979 to 1993) was for Quercus spp. (17%); followed by Platanus spp. (15%), Poaceae (15%), Cupressaceae (11%), Olea spp. (9%), Pinus spp. (7%), Populus spp. (4%), and Plantago spp. (4%). The most predominant pollens from January to April are tree pollens (Cupressaceae, Alnus, Fraxinus, Ulmus, Populus, Platanus, and Morus), although these are also abudant in May and June (Quercus, Olea, and Pinus spp.). The grass pollination period shows a double curve: the first peak occurs from February to April (8% of yearly grasses), and the second peak occurs from May to July (90% of yearly grasses). Among allergenically significant weeds, the most notable is Plantago; in contrast, Rumex, Urticaceae, Cheno-Amaranthaceae, and Artemisia spp. have very low concentrations (< or = 2% yearly total pollens). The most significant allergenic pollen is that of grasses, with a prevalence of positive prick test results of 94%, followed by Olea europaea (61%), Plantago lagopus (53%), Platanus hybrida (52%), and Cupressus arizonica (20%). The population of Madrid is exposed to high concentrations of allergenic pollen from February to July, although the most intense period is from May to June. Grass pollens are the most important cause of pollinosis in this area.

Relationship between airborne pollen count and treatment outcome in Japanese cedar pollinosis patients.

PubMed

Takasaki, Kenji; Enatsu, Kaori; Kumagami, Hidetaka; Takahashi, Haruo

2009-05-01

In Japan, information on daily Japanese cedar pollen counts is made public during pollen season. If symptom severity and treatment outcome are predictable according to these pollen counts, management of seasonal allergic rhinitis may become more precise. The aims of the study were to evaluate the relationship between airborne pollen counts, symptom severity and treatment outcome in Japanese cedar pollinosis patients. In the randomized study, patients with moderate to most severe Japanese pollinosis were treated with fexofenadine (60 mg BD) or fexofenadine and nasal corticosteroids for 2 weeks. During the same period daily airborne pollen counts were measured. A total of 105 adult patients were enrolled. No difference of treatment efficacy was seen among groups. Detailed results of efficacy and safety were previously described elsewhere. In univariate analysis, the mean cumulative amount of airborne pollen exposure for 4 days prior to the study tended to affect symptom severity (P = 0.053) and the mean cumulative amount of airborne pollen during the treatment period tended to show difference among five treatment outcome categories (P = 0.066). In multivariate analysis, the mean cumulative amount of airborne pollen exposure for 4 days prior to the study was identified as the only significant factor of symptom severity (P = 0.0327) and cumulative amount of airborne pollen during the treatment period (P = 0.027) and allergic history (P = 0.027) were significant factors of treatment outcomes. No serious adverse effect was reported during the study. The amount of airborne pollen may be predictive of both symptom severity and treatment outcome.

A 30-day-ahead forecast model for grass pollen in north London, United Kingdom.

PubMed

Smith, Matt; Emberlin, Jean

2006-03-01

A 30-day-ahead forecast method has been developed for grass pollen in north London. The total period of the grass pollen season is covered by eight multiple regression models, each covering a 10-day period running consecutively from 21 May to 8 August. This means that three models were used for each 30-day forecast. The forecast models were produced using grass pollen and environmental data from 1961 to 1999 and tested on data from 2000 and 2002. Model accuracy was judged in two ways: the number of times the forecast model was able to successfully predict the severity (relative to the 1961-1999 dataset as a whole) of grass pollen counts in each of the eight forecast periods on a scale of 1 to 4; the number of times the forecast model was able to predict whether grass pollen counts were higher or lower than the mean. The models achieved 62.5% accuracy in both assessment years when predicting the relative severity of grass pollen counts on a scale of 1 to 4, which equates to six of the eight 10-day periods being forecast correctly. The models attained 87.5% and 100% accuracy in 2000 and 2002, respectively, when predicting whether grass pollen counts would be higher or lower than the mean. Attempting to predict pollen counts during distinct 10-day periods throughout the grass pollen season is a novel approach. The models also employed original methodology in the use of winter averages of the North Atlantic Oscillation to forecast 10-day means of allergenic pollen counts.

Female Reproductive Tissues Are the Primary Target of Agrobacterium-Mediated Transformation by the Arabidopsis Floral-Dip Method1

PubMed Central

Desfeux, Christine; Clough, Steven J.; Bent, Andrew F.

2000-01-01

The floral-dip method for Agrobacterium-mediated transformation of Arabidopsis allows efficient plant transformation without need for tissue culture. To facilitate use with other plant species, we investigated the mechanisms that underlie this method. In manual outcrossing experiments, application of Agrobacterium tumefaciens to pollen donor plants did not produce any transformed progeny, whereas application of Agrobacterium to pollen recipient plants yielded transformants at a rate of 0.48%. Agrobacterium strains with T-DNA carrying gusA (encoding β-glucuronidase [GUS]) under the control of 35S, LAT52, or ACT11 promoters revealed delivery of GUS activity to developing ovules, whereas no GUS staining of pollen or pollen tubes was observed. Transformants derived from the same seed pod contained independent T-DNA integration events. In Arabidopsis flowers, the gynoecium develops as an open, vase-like structure that fuses to form closed locules roughly 3 d prior to anthesis. In correlation with this fact, we found that the timing of Agrobacterium infection was critical. Transformants were obtained and GUS staining of ovules and embryo sacs was observed only if the Agrobacterium were applied 5 d or more prior to anthesis. A 6-fold higher rate of transformation was obtained with a CRABS-CLAW mutant that maintains an open gynoecium. Our results suggest that ovules are the site of productive transformation in the floral-dip method, and further suggest that Agrobacterium must be delivered to the interior of the developing gynoecium prior to locule closure if efficient transformation is to be achieved. PMID:10889238

Female reproductive tissues are the primary target of Agrobacterium-mediated transformation by the Arabidopsis floral-dip method.

PubMed

Desfeux, C; Clough, S J; Bent, A F

2000-07-01

The floral-dip method for Agrobacterium-mediated transformation of Arabidopsis allows efficient plant transformation without need for tissue culture. To facilitate use with other plant species, we investigated the mechanisms that underlie this method. In manual outcrossing experiments, application of Agrobacterium tumefaciens to pollen donor plants did not produce any transformed progeny, whereas application of Agrobacterium to pollen recipient plants yielded transformants at a rate of 0.48%. Agrobacterium strains with T-DNA carrying gusA (encoding beta-glucuronidase [GUS]) under the control of 35S, LAT52, or ACT11 promoters revealed delivery of GUS activity to developing ovules, whereas no GUS staining of pollen or pollen tubes was observed. Transformants derived from the same seed pod contained independent T-DNA integration events. In Arabidopsis flowers, the gynoecium develops as an open, vase-like structure that fuses to form closed locules roughly 3 d prior to anthesis. In correlation with this fact, we found that the timing of Agrobacterium infection was critical. Transformants were obtained and GUS staining of ovules and embryo sacs was observed only if the Agrobacterium were applied 5 d or more prior to anthesis. A 6-fold higher rate of transformation was obtained with a CRABS-CLAW mutant that maintains an open gynoecium. Our results suggest that ovules are the site of productive transformation in the floral-dip method, and further suggest that Agrobacterium must be delivered to the interior of the developing gynoecium prior to locule closure if efficient transformation is to be achieved.

Gene flow in maize fields with different local pollen densities.

PubMed

Goggi, A Susana; Lopez-Sanchez, Higinio; Caragea, Petrutza; Westgate, Mark; Arritt, Raymond; Clark, Craig A

2007-08-01

The development of maize (Zea mays L.) varieties as factories of pharmaceutical and industrial compounds has renewed interest in controlling pollen dispersal. The objective of this study was to compare gene flow into maize fields of different local pollen densities under the same environmental conditions. Two fields of approximately 36 ha were planted with a nontransgenic, white hybrid, in Ankeny, Iowa, USA. In the center of both fields, a 1-ha plot of a yellow-seeded stacked RR/Bt transgenic hybrid was planted as a pollen source. Before flowering, the white receiver maize of one field was detasseled in a 4:1 ratio to reduce the local pollen density (RPD). The percentage of outcross in the field with RPD was 42.2%, 6.3%, and 1.3% at 1, 10, and 35 m from the central plot, respectively. The percentage of outcross in the white maize with normal pollen density (NPD) was 30.1%, 2.7%, and 0.4%, respectively, at these distances. At distances greater than 100 m, the outcross frequency decreased below 0.1 and 0.03% in the field with RPD and NPD, respectively. A statistical model was used to compare pollen dispersal based on observed outcross percentages. The likelihood ratio test confirmed that the models of outcrossing in the two fields were significantly different (P is practically 0). Results indicated that when local pollen is low, the incoming pollen has a competitive advantage and the level of outcross is significantly greater than when the local pollen is abundant.

High temperature exposure did not affect induced 2n pollen viability in Populus.

PubMed

Tian, Mengdi; Zhang, Yuan; Liu, Yan; Kang, Xiangyang; Zhang, Pingdong

2018-02-11

High temperature exposure is widely used as a physical mutagenic agent to induce 2n gametes in Populus. However, whether high temperature exposure affects induced 2n pollen viability remains unknown. To clarify whether high temperature exposure affected the induced 2n pollen viability, 2n pollen induced by 38 and 41 °C temperatures, pollen morphology, 2n pollen germination in vitro, and crossing induced 2n pollen with normal gametes to produce a triploid was, based on observations of meiosis, conducted in Populus canescens. We found that the dominant meiotic stages (F = 56.6, p < .001) and the treatment duration (F = 21.4, p < .001) significantly affected the occurrence rate of induced 2n pollen. A significant decrease in pollen production and an increase in aborted pollen were observed (p < .001). High temperature sometimes affected in ectexine deposition and some narrow furrows were also analysed via details of ectexine structure. However, no significant difference in 2n pollen germination rate was observed between natural 2n pollen (26.7%) and high-temperature-induced 2n pollen (26.2%), and 42 triploids were created by crossing high-temperature-induced 2n pollen, suggesting that 38 and 41 °C temperatures exposure will not result in dysfunctional induced 2n pollen. © 2018 John Wiley & Sons Ltd.

Fresh and Stored Pollen From Slash and Loblolly Pines Compared For Seed Yields

Treesearch

John F. Kraus; Davie L. Hunt

1970-01-01

Seed yields showed no consistent differences between fresh and stored pollen from 8 years of controlled pollination on slash pine and 4 years on loblolly pine. Collection of male strobili at the proper stage of pollen maturity was an important factor in obtaining good seed yields from stored pollen. Criteria are described which were useful in determining when to...

CRISPR/Cas9-mediated knockout of PiSSK1 reveals essential role of S-locus F-box protein-containing SCF complexes in recognition of non-self S-RNases during cross-compatible pollination in self-incompatible Petunia inflata.

PubMed

Sun, Linhan; Kao, Teh-Hui

2018-06-01

Function of Petunia PiSSK1. Self-incompatibility (SI), an inbreeding-preventing mechanism, is regulated in Petunia inflata by the polymorphic S-locus, which houses multiple pollen-specific S-locus F-box (SLF) genes and a single pistil-specific S-RNase gene. S 2 -haplotype and S 3 -haplotype possess the same 17 polymorphic SLF genes (named SLF1 to SLF17), and each SLF protein produced in pollen is assembled into an SCF (Skp1-Cullin1-F-box) E3 ubiquitin ligase complex. A complete suite of SLF proteins is thought to collectively interact with all non-self S-RNases to mediate their ubiquitination and degradation by the 26S proteasome, allowing cross-compatible pollination. For each SCF SLF complex, the Cullin1 subunit (named PiCUL1-P) and Skp1 subunit (named PiSSK1), like the F-box protein subunits (SLFs), are pollen-specific, raising the possibility that they also evolved specifically to function in SI. Here we used CRISPR/Cas9-meditated genome editing to generate frame-shift indel mutations in PiSSK1 and examined the SI behavior of a T 0 plant (S 2 S 3 ) with biallelic mutations in the pollen genome and two progeny plants (S 2 S 2 ) each homozygous for one of the indel alleles and not carrying the Cas9-containing T-DNA. Their pollen was completely incompatible with pistils of seven otherwise-compatible S-genotypes, but fully compatible with pistils of an S 3 S 3 transgenic plant in which production of S 3 -RNase was completely suppressed by an antisense S 3 -RNase gene, and with pistils of immature flower buds, which produce little S-RNase. These results suggest that PiSSK1 specifically functions in SI and support the hypothesis that SLF-containing SCF complexes are essential for compatible pollination.

Effects of male fecundity, interindividual distance and anisotropic pollen dispersal on mating success in a Scots pine (Pinus sylvestris) seed orchard

PubMed Central

Torimaru, T; Wennström, U; Lindgren, D; Wang, X-R

2012-01-01

Quantifying the effect of pollen dispersal and flowering traits on mating success is essential for understanding evolutionary responses to changing environments and establishing strategies for forest tree breeding. This study examined, quantitatively, the effects of male fecundity, interindividual distance and anisotropic pollen dispersal on the mating success of Scots pine (Pinus sylvestris), utilizing a well-mapped Scots pine seed orchard. Paternity analysis of 1021 seeds sampled from 87 trees representing 28 clones showed that 53% of the seeds had at least one potential pollen parent within the orchard. Pronounced variation in paternal contribution was observed among clones. Variations in pollen production explained up to 78% of the variation in mating success, which was 11.2 times greater for clones producing the largest amount of pollen than for clones producing the least pollen. Mating success also varied with intertree distance and direction, which explained up to 28% of the variance. Fertilization between neighboring trees 2.3 m apart was 2.4 times more frequent than between trees 4.6 m apart, and up to 12.4 times higher for trees downwind of the presumed prevailing wind direction than for upwind trees. The effective number of pollen donors recorded in the seed orchard (12.2) was smaller than the theoretical expectation (19.7). Based on the empirical observations, a mating model that best describes the gene dispersal pattern in clonal seed orchards was constructed. PMID:21897440

The importance of pollen chemistry in evolutionary host shifts of bees

PubMed Central

Vanderplanck, Maryse; Vereecken, Nicolas J.; Grumiau, Laurent; Esposito, Fabiana; Lognay, Georges; Wattiez, Ruddy; Michez, Denis

2017-01-01

Although bee-plant associations are generally maintained through speciation processes, host shifts have occurred during evolution. Understanding shifts between both phylogenetically and morphologically unrelated plants (i.e., host-saltation) is especially important since they could have been key processes in the origin and radiation of bees. Probably far from being a random process, such host-saltation might be driven by hidden constraints associated with plant traits. We selected two clades of oligolectic bees (i.e., Colletes succinctus group and Melitta leporina group) foraging on co-flowering but unrelated host-plants to test this hypothesis. We analyzed floral scent, floral color and chemical composition of pollen from host and non-host plants of these two clades. We did not find evidence for host-plant evolution in the Melitta leporina group driven by one of the assayed floral traits. On the contrary, hosts of the C. succinctus group display similar primary nutritive content of pollen (i.e., amino acids and sterols) but not similar floral scent or color, suggesting that shared pollen chemistry probably mediates saltation in this clade. Our study revealed that constraints shaping floral associations are diverse and clearly depend on species life-history traits, but evidence suggests that pollen chemistry may act as a major floral filter and guide evolutionary host-shifts. PMID:28216663

Pollen-tube tip growth requires a balance of lateral propagation and global inhibition of Rho-family GTPase activity

PubMed Central

Hwang, Jae-Ung; Wu, Guang; Yan, An; Lee, Yong-Jik; Grierson, Claire S.; Yang, Zhenbiao

2010-01-01

Rapid tip growth allows for efficient development of highly elongated cells (e.g. neuronal axons, fungal hyphae and pollen tubes) and requires an elaborate spatiotemporal regulation of the growing region. Here, we use the pollen tube as a model to investigate the mechanism regulating the growing region. ROPs (Rho-related GTPases from plants) are essential for pollen tip growth and display oscillatory activity changes in the apical plasma membrane (PM). By manipulating the ROP activity level, we showed that the PM distribution of ROP activity as an apical cap determines the tip growth region and that efficient tip growth requires an optimum level of the apical ROP1 activity. Excessive ROP activation induced the enlargement of the tip growth region, causing growth depolarization and reduced tube elongation. Time-lapse analysis suggests that the apical ROP1 cap is generated by lateral propagation of a localized ROP activity. Subcellular localization and gain- and loss-of-function analyses suggest that RhoGDI- and RhoGAP-mediated global inhibition limits the lateral propagation of apical ROP1 activity. We propose that the balance between the lateral propagation and the global inhibition maintains an optimal apical ROP1 cap and generates the apical ROP1 activity oscillation required for efficient pollen-tube elongation. PMID:20053639

Effects of virus infection on pollen production and pollen performance: Implications for the spread of resistance alleles.

PubMed

Harth, Jacquelyn E; Winsor, James A; Weakland, Danelle R; Nowak, Kayla J; Ferrari, Matthew J; Stephenson, Andrew G

2016-03-01

Studies over the past 25 years have shown that environmental stresses adversely affect male function, including pollen production and pollen performance (germination and pollen tube growth rate). Consequently, genetic variation among plants in resistance to a stress has the potential to impact pollen donation to conspecifics and, if deposited onto a stigma, the ability of the pollen to achieve fertilization. We examined the effects of a nonlethal virus epidemic on pollen production and pollen performance in a population of susceptible and resistant (transgenic) wild squash (Cucurbita pepo subsp. texana). We grew 135 susceptible and 45 virus-resistant wild squash plants in each of two 0.4-ha fields, initiated a zucchini yellow mosaic virus (ZYMV) epidemic, and recorded staminate and pistillate flower production per plant over the field season and the total number of mature fruit. We also assessed pollen production per flower on ZYMV-infected and non-infected plants and the ability of pollen from flowers on infected and non-infected plants to achieve fertilization under competitive conditions. ZYMV infection reduced flower and fruit production per plant and pollen production per flower. Pollen from infected plants was also less likely to sire a seed under competitive conditions. ZYMV infection adversely impacts the amount of pollen that can be donated to conspecifics, and pollen competition within the styles increases the probability that the ovules are fertilized by pollen from plants that are thriving when challenged by a viral disease. © 2016 Botanical Society of America.

Astylus atromaculatus (Coleoptera: Melyridae): abundance and role in pollen dispersal in Bt and non-Bt cotton in South Africa.

PubMed

Pierre, Jacqueline; Hofs, Jean-Luc

2010-10-01

In South Africa, modified Bt (Cry1 Ac) cotton cultivars and organic ones coexist. This raises the question of the risk of dissemination of genetically modified (GM) pollen to non-GM crops by visiting insects. We inventoried the flower-visiting insects in Bt and non-Bt cotton fields of the South African Highveld region and investigated their role in pollen dispersal. Their diversity and abundance varied slightly among sites, with Astylus atromaculatus as the predominant insect on both Bt and non-Bt cotton flowers. The other major flower-visiting species were Apis mellifera and solitary Apidae. No differences were found in the abundance of each taxum between Bt and non-Bt cotton except for Scoliidae and Nitidulidae, which were scarce overall (<0.5%) but more abundant on the non-Bt flowers in the central area of the field at one site. The pollen load on A. atromaculatus was as high as on Apis mellifera. Cage tests showed that A. atromaculatus can pollinate female cotton plants by transferring pollen from male donor plants. In the field, the flight range of this insect was generally short (25 m), but it can occasionally reach up to 200 m or even more. This study therefore highlights that A. atromaculatus, commonly regarded as a pest, could be an unexpected but efficient pollinator. Because its population density can be high, this species could mediate unwanted cotton pollen flow when distances between coexiting fields are not sufficient.

Pollination ecology of Silene acutifolia (Caryophyllaceae): floral traits variation and pollinator attraction.

PubMed

Buide, María Luisa

2006-02-01

The floral display influences the composition of pollinators interacting with a plant species. Geographic and temporal variation in pollinator composition complicates the understanding of the evolutionary consequences of floral display variation. This paper analyses the relationships between Silene acutifolia, a hermaphroditic perennial herb, and its pollinators, based on field studies in the north-west of Spain. Studies were conducted over three years (1997-1999). Firstly, the main pollinators of this species were determined for two years in one population. Secondly, pollen limitation in fruit and seed production was analysed by supplementary hand pollinations, and counting the pollen grains and tubes growing in styles for two different-sized populations. Finally, the effect of flower size and number on the rate of visitation and total seed number was examined for 15 marked plants. The primary pollinators were long-tongued insects, including Hymenoptera, Lepidoptera and Diptera, but the composition and visitation frequencies differed between years. Pollen limitation occurred in one of the years of study. There was between-population variation in the number of pollen grains and pollen tubes found in styles, suggesting pollen limitation in one population. Overall, pollinators visited plants with more open flowers more frequently, and pollinated more flowers within these plants. Conversely, petal and calyx sizes had no effect on insect visitation. Plants with higher rates of visits produced higher number of seeds, suggesting that pollinator-mediated limitation of seed and fruit production may be important in some years.

Strong and frequent T-cell responses to the minor allergen Phl p 12 in Spanish patients IgE-sensitized to Profilins.

PubMed

Lund, G; Brand, S; Ramos, T; Jimeno, L; Boissy, P; Vega, F; Arina, M; Christensen, L H; Hoof, I; Meno, K H; Barber, D; Blanco, C; Würtzen, P A; Andersen, P S

2018-05-01

Profilins are dominant pan-allergens known to cause cross-sensitization, leading to clinical symptoms such as pollen-food syndrome. This study aimed to determine the T-cell response to Phl p 12 in profilin-sensitized patients, by measuring the prevalence, strength and cross-reactivity to clinically relevant profilins. The release of Phl p allergens from pollen was determined by mass spectrometry and immunochemistry. T-cell responses, epitope mapping and cross-reactivity to profilins (Phl p 12, Ole e 2, Bet v 2 and Mal d 4) were measured in vitro using PBMCs from 26 Spanish grass-allergic donors IgE-sensitized to profilin. Cross-reactivity was addressed in vivo using 2 different mouse strains (BALB/c and C3H). Phl p 12 and Phl p 1 are released from pollen simultaneously and in similar amounts. Both T-cell response frequency (17/26 donors) and strength were comparable between Phl p 12 and Phl p 1. T-cell cross-reactivity to other profilins correlated with overall sequence homology, and 2 immunodominant epitope regions of Phl p 12 were identified. Data from mice immunized with Phl p 12 showed that cross-reactivity to Bet v 2 was mediated by conserved epitopes and further influenced by additional genetic factors, likely to be MHC II. The strength, prevalence and cross-reactivity of T-cell responses towards Phl p 12 are comparable to the major allergen Phl p 1, which supports the hypothesis that T cells to Phl p 12 can play an important role in development of allergic symptoms, such as those associated with pollen-food syndrome. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Transport of airborne pollen into the city of Thessaloniki: the effects of wind direction, speed and persistence

NASA Astrophysics Data System (ADS)

Damialis, Athanasios; Gioulekas, Dimitrios; Lazopoulou, Chariklia; Balafoutis, Christos; Vokou, Despina

2005-01-01

We examined the effect of the wind vector analyzed into its three components (direction, speed and persistence), on the circulation of pollen from differe nt plant taxa prominent in the Thessaloniki area for a 4-year period (1996- 1999). These plant taxa were Ambrosia spp., Artemisia spp., Chenopodiaceae, spp., Cupressaceae, Olea europaea, Pinaceae, Platanus spp., Poaceae, Populus spp., Quercus spp., and Urticaceae. Airborne pollen of Cupressaceae, Urticaceae, Quercus spp. and O. europaea make up approximately 70% of the total average annual pollen counts. The set of data that we worked with represented days without precipitation and time intervals during which winds blew from the same direction for at least 4 consecutive hours. We did this in order to study the effect of the different wind components independently of precipitation, and to avoid secondary effects produced by pollen resuspension phenomena. Factorial regression analysis among the summed bi-hourly pollen counts for each taxon and the values of wind speed and persistence per wind direction gave significant results in 22 cases (combinations of plant taxa and wind directions). The pollen concentrations of all taxa correlated significantly with at least one of the three wind components. In seven out of the 22 taxon-wind direction combinations, the pollen counts correlated positively with wind persistence, whereas this was the case for only two of the taxon-wind speed combinations. In seven cases, pollen counts correlated with the interaction effect of wind speed and persistence. This shows the importance of wind persistence in pollen transport, particularly when weak winds prevail for a considerable part of the year, as is the case for Thessaloniki. Medium/long-distance pollen transport was evidenced for Olea (NW, SW directions), Corylus (NW, SW), Poaceae (SW) and Populus (NW).

Transport and radiative impacts of atmospheric pollen using online, observation-based emissions

NASA Astrophysics Data System (ADS)

Wozniak, M. C.; Steiner, A. L.; Solmon, F.; Li, Y.

2015-12-01

Atmospheric pollen emitted from trees and grasses exhibits both a high temporal variability and a highly localized spatial distribution that has been difficult to quantify in the atmosphere. Pollen's radiative impact is also not quantified because it is neglected in climate modeling studies. Here we couple an online, meteorological active pollen emissions model guided by observations of airborne pollen to understand the role of pollen in the atmosphere. We use existing pollen counts from 2003-2008 across the continental U.S. in conjunction with a tree database and historical meteorological data to create an observation-based phenological model that produces accurately scaled and timed emissions. These emissions are emitted and transported within the regional climate model (RegCM4) and the direct radiative effect is calculated. Additionally, we simulate the rupture of coarse pollen grains into finer particles by adding a second size mode for pollen emissions, which contributes to the shortwave radiative forcing and also has an indirect effect on climate.

Impacts of oak pollen on allergic asthma in the United States ...

EPA Pesticide Factsheets

Oak pollen season length for moderate (RCP4.5) and severe climate change scenarios (RCP8.5) are estimated through 2090 using five climate models and published relationships between temperature, precipitation, and oak pollen season length. We calculated asthma ED visit counts associated with 1994-2010 average oak pollen concentrations and simulated future oak pollen season length changes using the Environmental Benefits Mapping and Analysis Program (BenMAP-CE), driven by epidemiologically-derived concentration-response relationships. Future climate change is expected to lengthen and intensify pollen seasons in the U.S., potentially increasing incidence of allergic asthma. We developed a proof-of-concept approach for estimating asthma emergency department (ED) visits in the U.S. associated with present-day and climate-induced changes in oak pollen.

A 10-year climatology of pollen aerosol for the continental United States: implications for aerosol-climate interactions

NASA Astrophysics Data System (ADS)

Wozniak, M. C.

2016-12-01

Our current understanding of biological particles and their role in the climate system is uncertain. Pollen, a primary biological aerosol particle, has been understudied in the context of climate and atmospheric science because of its coarse size (10-100 µm). Local coarse grain pollen concentrations can reach up to 10,000 grains m-3, and when ruptured by wet or turbulent atmospheric conditions, can produce fine particles (sub-pollen particles, 10-1000 nm) that may increase pollen's lifetime in the atmosphere. Therefore, pollen contributes to both coarse and fine particle loads in the atmosphere that may have climatic impacts. During peak pollen emissions season, what impacts does pollen have on aerosol concentrations in the atmosphere and their indirect forcing? Here we use a model of accurately timed and scaled pollen and sub-pollen particle emissions with climate-dependent phenological dates for four plant functional types (deciduous broadleaf, evergreen needleleaf, grass and ragweed) that dominate emissions across the continental United States. Terrestrial pollen emissions are coupled with the land component of a regional climate model (RegCM4-CLM), and are transported as atmospheric tracers that are allowed interact with radiation and clouds, accounting for the direct and indirect effects of pollen. A ten-year climatology of pollen emissions and climate interactions is calculated for both pollen grains and sub-pollen particles. Its implications for the local and overall radiation budget, aerosol-cloud-precipitation interactions and regional climate are discussed.

Characteristics of modern pollen rain and the relationship to vegetation in sagebrush-steppe environments of Montana, USA

NASA Astrophysics Data System (ADS)

Briles, C.; Bryant, V.

2010-12-01

Variations in pollen production and dispersal characteristics among plant species complicate our ability to determine direct relationships between deposited pollen and actual vegetation. In order to better understand modern pollen-vegetation relationships, we analyzed pollen from 61 samples taken from sagebrush-steppe environments across Montana and compared them with the actual vegetation composition at each site. We also determined to what degree sagebrush-steppe communities can be geographically distinguished from one another based on their pollen signature. Pollen preservation was good, especially in wetter environments, with pollen degradataion ranging from 4-15%. Diploxylon Pinus was the primary contributor to the pollen rain, even in plots where pine trees did not occur or were several kilometers from the plot. Artemisia and grass pollen are underrepresented in the soils samples, while Chenopodiaceae and Juniperus pollen are overrepresented when compared to actual vegetation composition. Insect-pollinated species are present only in very minor amounts in the soil samples, even though some (e.g., Brassica) are abundant in the plots. In general, pollen spectra show significant differences between regions, however, within each region the individual spectra are not statistically significant from one another. An understanding of modern pollen-vegetation relationships and the palynological “fingerprint” of sagebrush-steppe communities aid in climatic and ecological interpretations of fossil pollen assemblages. The data also provide important control samples for forensics studies that use pollen to geolocate an object or person to a crime scene.

Effects of simulated acid rain on pollen physiology and ultrastructure in the apple.

PubMed

Bellani, L M; Rinallo, C; Muccifora, S; Gori, P

1997-01-01

Viability, germination and tube length were investigated in pollen grains of field-grown 'Summerred' apple trees (Malus domestica Borkh) exposed to deionized water, rainfall or simulated acid rain at pH 5.6, 4.0 and 3.0. Pollen viability and germination significantly decreased with lower values of pH and with increasing number of treatments. The effects of pH 5.6 and natural rainfall were not significant. Electron microscope investigation of vegetative pollen cells of plants exposed to acid rain at pH 4.0 and 3.0 showed modified features in mitochondria, plastids and endoplasmic reticulum.

Integrating Membrane Transport with Male Gametophyte Development and Function through Transcriptomics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bock KW; D Honys; JM. Ward

Male fertility depends on the proper development of the male gametophyte, successful pollen germination, tube growth and delivery of the sperm cells to the ovule. Previous studies have shown that nutrients like boron, and ion gradients or currents of Ca2+, H+, and K+ are critical for pollen tube growth. However, the molecular identities of transporters mediating these fluxes are mostly unknown. As a first step to integrate transport with pollen development and function, a genome-wide analysis of transporter genes expressed in the male gametophyte at four developmental stages was conducted. About 1269 genes encoding classified transporters were collected from themore » Arabidopsis thaliana genome. Of 757 transporter genes expressed in pollen, 16% or 124 genes, including AHA6, CNGC18, TIP1.3 and CHX08, are specifically or preferentially expressed relative to sporophytic tissues. Some genes are highly expressed in microspores and bicellular pollen (COPT3, STP2, OPT9); while others are activated only in tricellular or mature pollen (STP11, LHT7). Analyses of entire gene families showed that a subset of genes, including those expressed in sporophytic tissues, were developmentally-regulated during pollen maturation. Early and late expression patterns revealed by transcriptome analysis are supported by promoter::GUS analyses of CHX genes and by other methods. Recent genetic studies based on a few transporters, including plasma membrane H+ pump AHA3, Ca2+ pump ACA9, and K+ channel SPIK, further support the expression patterns and the inferred functions revealed by our analyses. Thus, revealing the distinct expression patterns of specific transporters and unknown polytopic proteins during microgametogenesis provides new insights for strategic mutant analyses necessary to integrate the roles of transporters and potential receptors with male gametophyte development.« less

Integrating membrane transport with male gametophyte development and function through transcriptomics.

PubMed

Bock, Kevin W; Honys, David; Ward, John M; Padmanaban, Senthilkumar; Nawrocki, Eric P; Hirschi, Kendal D; Twell, David; Sze, Heven

2006-04-01

Male fertility depends on the proper development of the male gametophyte, successful pollen germination, tube growth, and delivery of the sperm cells to the ovule. Previous studies have shown that nutrients like boron, and ion gradients or currents of Ca2+, H+, and K+ are critical for pollen tube growth. However, the molecular identities of transporters mediating these fluxes are mostly unknown. As a first step to integrate transport with pollen development and function, a genome-wide analysis of transporter genes expressed in the male gametophyte at four developmental stages was conducted. Approximately 1,269 genes encoding classified transporters were collected from the Arabidopsis (Arabidopsis thaliana) genome. Of 757 transporter genes expressed in pollen, 16% or 124 genes, including AHA6, CNGC18, TIP1.3, and CHX08, are specifically or preferentially expressed relative to sporophytic tissues. Some genes are highly expressed in microspores and bicellular pollen (COPT3, STP2, OPT9), while others are activated only in tricellular or mature pollen (STP11, LHT7). Analyses of entire gene families showed that a subset of genes, including those expressed in sporophytic tissues, was developmentally regulated during pollen maturation. Early and late expression patterns revealed by transcriptome analysis are supported by promoter::beta-glucuronidase analyses of CHX genes and by other methods. Recent genetic studies based on a few transporters, including plasma membrane H+ pump AHA3, Ca2+ pump ACA9, and K+ channel SPIK, further support the expression patterns and the inferred functions revealed by our analyses. Thus, revealing the distinct expression patterns of specific transporters and unknown polytopic proteins during microgametogenesis provides new insights for strategic mutant analyses necessary to integrate the roles of transporters and potential receptors with male gametophyte development.

Bee pollen: a dangerous food for allergic children. Identification of responsible allergens.

PubMed

Martín-Muñoz, M F; Bartolome, B; Caminoa, M; Bobolea, I; Ara, M C Garcia; Quirce, S

2010-01-01

Bee pollen has been proposed as a food supplement, but it can be a dangerous food for people with allergy. We study an allergic reaction after ingestion of bee pollen in a 4-year-old boy who had developed rhinitis in the last spring and autumn. We performed a prick-by-prick test with bee pollen and skin prick tests with the most important local pollens, house dust mites, common fungi, and animal danders. The levels of serum tryptase, serum total IgE and specific IgE against bee venom and local pollen extracts were determined. The composition of the bee pollen was analysed and SDS-PAGE immunoblotting and blotting-inhibition were carried out. Prick tests were positive to bee pollen and all local pollens extracts and negative to any other allergen sources. The bee pollen sample contained pollens from Quercus genus, and Asteraceae (Compositae) and Rosaceae families. Total IgE was 435 kU/l. Serum specific IgE to bee pollen was 6 kU/l and greater than 0.35 kU/L against pollens from Artemisia vulgaris, Taraxacum officinalis, Cupressus arizonica, Olea europaea, Platanus acerifolia and Lolium perenne as well as to n Art v 1 and other pollen marker allergens. Tryptase level was 3.5 mcg/mL. SDS-PAGE immunoblotting-inhibition points to Asteraceae pollen as the possible cause of the allergic reaction. Foods derived from bees can be dangerous to people with allergy to pollen. Copyright © 2009 SEICAP. Published by Elsevier Espana. All rights reserved.

Taxonomy and pollen morphology of Ankyropetalum Fenzl (Caryophyllaceae) species in Türkiye.

PubMed

Muca, Belkis; Ozçelik, Hasan

2014-04-01

There are 4 species belong to Ankyropetalum Fenzl (Caryophyllaceae) genus and three of them (A. reuteri Boiss. and Hausskn, A. arsusianum Kotschy ex Boiss. and A. gypsophiloides Fenzl) are distributed in Turkey. There are doubts about taxonomical studies depending on only morphological characteristics. This study has been made to put forth that palinological studies also contribute taxonomical studies. Pollen morphology of the three species belong to Ankyropetalum Fenzl (Caryophyllaceae) genus distributed in Turkey examined with ray microscope and electron microscope in this study. Results evaluated according to Duncan's multiple range test using SPSS statistic program. Pollen's polar and ecvatoral seeming photographs were taken in preparates. Morphology of pollens examined with 50 repetition for each taxon and morphological assessments were made. The common trait of pollens can be summarized as they are circular, oblate and prolate spheroidal, periporate (pore numbers ranged between 20-33), operculum is granulated, annulus is distinct, the form of pollens are tectat. Definition of pollens are given for each taxon, diagnostic specifications recognized as important are used for making diagnosis key. The difference between species are as below: A. arsusianum's pollen shape is oblate-spheroidal, type of pollen is periporate, pore numbers are between 23-33, form of pollen is tectat, ornamentation is perforate. A. reuteri's pollen shape is prolate-spheroidal, type of pollen is periporate, pore numbers are between 20-33, form of pollen is tectat, ornamentation is from perforate to eureticulate A. gypsophiloides pollen shape is oblate-spheroidal, type of pollen is periporate, pore numbers are between 21-30, form of pollen is tectat, ornamentation is perforate.

Facilitation of Allergic Sensitization and Allergic Airway Inflammation by Pollen-Induced Innate Neutrophil Recruitment

PubMed Central

Hosoki, Koa; Aguilera-Aguirre, Leopoldo; Brasier, Allan R.; Kurosky, Alexander; Boldogh, Istvan

2016-01-01

Neutrophil recruitment is a hallmark of rapid innate immune responses. Exposure of airways of naive mice to pollens rapidly induces neutrophil recruitment. The innate mechanisms that regulate pollen-induced neutrophil recruitment and the contribution of this neutrophilic response to subsequent induction of allergic sensitization and inflammation need to be elucidated. Here we show that ragweed pollen extract (RWPE) challenge in naive mice induces C-X-C motif ligand (CXCL) chemokine synthesis, which stimulates chemokine (C-X-C motif) receptor 2 (CXCR2)-dependent recruitment of neutrophils into the airways. Deletion of Toll-like receptor 4 (TLR4) abolishes CXCL chemokine secretion and neutrophil recruitment induced by a single RWPE challenge and inhibits induction of allergic sensitization and airway inflammation after repeated exposures to RWPE. Forced induction of CXCL chemokine secretion and neutrophil recruitment in mice lacking TLR4 also reconstitutes the ability of multiple challenges of RWPE to induce allergic airway inflammation. Blocking RWPE-induced neutrophil recruitment in wild-type mice by administration of a CXCR2 inhibitor inhibits the ability of repeated exposures to RWPE to stimulate allergic sensitization and airway inflammation. Administration of neutrophils derived from naive donor mice into the airways of Tlr4 knockout recipient mice after each repeated RWPE challenge reconstitutes allergic sensitization and inflammation in these mice. Together these observations indicate that pollen-induced recruitment of neutrophils is TLR4 and CXCR2 dependent and that recruitment of neutrophils is a critical rate-limiting event that stimulates induction of allergic sensitization and airway inflammation. Inhibiting pollen-induced recruitment of neutrophils, such as by administration of CXCR2 antagonists, may be a novel strategy to prevent initiation of pollen-induced allergic airway inflammation. PMID:26086549

Facilitation of Allergic Sensitization and Allergic Airway Inflammation by Pollen-Induced Innate Neutrophil Recruitment.

PubMed

Hosoki, Koa; Aguilera-Aguirre, Leopoldo; Brasier, Allan R; Kurosky, Alexander; Boldogh, Istvan; Sur, Sanjiv

2016-01-01

Neutrophil recruitment is a hallmark of rapid innate immune responses. Exposure of airways of naive mice to pollens rapidly induces neutrophil recruitment. The innate mechanisms that regulate pollen-induced neutrophil recruitment and the contribution of this neutrophilic response to subsequent induction of allergic sensitization and inflammation need to be elucidated. Here we show that ragweed pollen extract (RWPE) challenge in naive mice induces C-X-C motif ligand (CXCL) chemokine synthesis, which stimulates chemokine (C-X-C motif) receptor 2 (CXCR2)-dependent recruitment of neutrophils into the airways. Deletion of Toll-like receptor 4 (TLR4) abolishes CXCL chemokine secretion and neutrophil recruitment induced by a single RWPE challenge and inhibits induction of allergic sensitization and airway inflammation after repeated exposures to RWPE. Forced induction of CXCL chemokine secretion and neutrophil recruitment in mice lacking TLR4 also reconstitutes the ability of multiple challenges of RWPE to induce allergic airway inflammation. Blocking RWPE-induced neutrophil recruitment in wild-type mice by administration of a CXCR2 inhibitor inhibits the ability of repeated exposures to RWPE to stimulate allergic sensitization and airway inflammation. Administration of neutrophils derived from naive donor mice into the airways of Tlr4 knockout recipient mice after each repeated RWPE challenge reconstitutes allergic sensitization and inflammation in these mice. Together these observations indicate that pollen-induced recruitment of neutrophils is TLR4 and CXCR2 dependent and that recruitment of neutrophils is a critical rate-limiting event that stimulates induction of allergic sensitization and airway inflammation. Inhibiting pollen-induced recruitment of neutrophils, such as by administration of CXCR2 antagonists, may be a novel strategy to prevent initiation of pollen-induced allergic airway inflammation.

Fast loading ester fluorescent Ca2+ and pH indicators into pollen of Pyrus pyrifolia.

PubMed

Qu, Haiyong; Jiang, Xueting; Shi, Zebin; Liu, Lianmei; Zhang, Shaoling

2012-01-01

Loading of Ca(2+)-sensitive fluorescent probes into plant cells is an essential step to measure activities of free Ca(2+) ions in cytoplasm with a fluorescent imaging technique. Fluo-3 is one of the most suitable Ca(2+) indicators for CLSM. We loaded pollen with fluo-3/AM at three different temperatures. Fluo-3/AM was successfully loaded into pollen at both low (4°C) and high (37°C) temperatures. However, high loading temperature was best suited for pollen, because germination rate of pollen and growth of pollen tubes were relatively little impaired and loading time was shortened. Moreover, Ca(2+) distribution increased in the three apertures of pollen after hydration and showed a Ca(2+) gradient, similar to the tip of growing pollen tubes. The same protocol can be used with the AM-forms of other fluorescent dyes for effective labeling. When loading BCECF-AM into pollen at high temperature, the pollen did not show a pH gradient after hydration. Ca(2+) activities and fluxes had the same periodicity as pollen germination, but pH did not show the same phase and mostly lagged behind. However, the clear zone was alkaline when pollen tube growth was slowed or stopped and turned acidic when growth recovered. It is likely that apical pH(i) regulated pollen tube growth.

[A VALIDATION STUDY OF THE IMPROVED PRODUCT FOR MEASURING JAPANESE CYPRESS POLLEN-SPECIFIC IgE (THERMO SCIENTIFIC™ ImmunoCAP™ ImmunoCAP JAPANESE CYPRESS POLLEN-SPECIFIC IgE)].

PubMed

Yonekura, Syuji; Okamoto, Yoshitaka; Nakayama, Satoshi

Japanese cypress pollen is a major causative allergen of seasonal allergic rhinitis in Japan. Although ImmunoCAP-specific immunoglobulin E (IgE) reagent Japanese cypress pollen has been widely used as a diagnostic aid, its sensitivity requires enhancement. This study evaluated an improved version of this reagent. Serum samples from 61 subjects who underwent Japanese cypress pollen exposure testing in an environmental challenge chamber in Chiba University were assessed using the conventional ImmunoCAPspecific IgE Japanese cypress pollen product and the improved product. In addition, specific IgE for Cha o 1 and Cha o 2, the primary allergen components of Japanese cypress pollen, was evaluated and their reactivity to specific IgE was compared between the conventional and improved products. The antibody titer of the improved product was approximately 1.8-fold that of the conventional product. In addition, higher correlations with Cha o 1 and Cha o 2 were observed for the improved product than for the conventional product. The clinical sensitivity (≥class 2) in 56 exposure test-positive subjects was better for the improved product (80.4%) than for the conventional product (71.4%). An improvement of the ImmunoCAP-specific IgE reagent Japanese cypress pollen resulted in enhanced Japanese cypress pollen-specific IgE sensitivity. The primary reason for this appeared to be an improved Cha o 1- and Cha o 2-specific IgE detectability.

The progamic phase of an early-divergent angiosperm, Annona cherimola (Annonaceae)

PubMed Central

Lora, J.; Hormaza, J. I.; Herrero, M.

2010-01-01

Background and Aims Recent studies of reproductive biology in ancient angiosperm lineages are beginning to shed light on the early evolution of flowering plants, but comparative studies are restricted by fragmented and meagre species representation in these angiosperm clades. In the present study, the progamic phase, from pollination to fertilization, is characterized in Annona cherimola, which is a member of the Annonaceae, the largest extant family among early-divergent angiosperms. Beside interest due to its phylogenetic position, this species is also an ancient crop with a clear niche for expansion in subtropical climates. Methods The kinetics of the reproductive process was established following controlled pollinations and sequential fixation. Gynoecium anatomy, pollen tube pathway, embryo sac and early post-fertilization events were characterized histochemically. Key Results A plesiomorphic gynoecium with a semi-open carpel shows a continuous secretory papillar surface along the carpel margins, which run from the stigma down to the obturator in the ovary. The pollen grains germinate in the stigma and compete in the stigma-style interface to reach the narrow secretory area that lines the margins of the semi-open stylar canal and is able to host just one to three pollen tubes. The embryo sac has eight nuclei and is well provisioned with large starch grains that are used during early cellular endosperm development. Conclusions A plesiomorphic simple gynoecium hosts a simple pollen–pistil interaction, based on a support–control system of pollen tube growth. Support is provided through basipetal secretory activity in the cells that line the pollen tube pathway. Spatial constraints, favouring pollen tube competition, are mediated by a dramatic reduction in the secretory surface available for pollen tube growth at the stigma–style interface. This extramural pollen tube competition contrasts with the intrastylar competition predominant in more recently derived lineages of angiosperms. PMID:19939980

Pollen selection under acid rain stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y.

To investigate whether acid rain stress induces pollen selection in nature, three different approaches were used, based on the assumption that the response of pollen grains to acid rain is controlled by an acid sensitive gene product. Germination of pollen from homozygous and heterozygous individuals under acid rain stress was examined to detect any differences in rate of germination between populations of homogeneous and heterogeneous pollen grains. In vitro and in vivo bulked segregant analysis using RAPDs was used to search for differences in DNA constitution between the survivors of acid rain stressed and non-acid rain stressed pollen populations inmore » vitro and between the progenies of acid rain stressed and non-acid rain stressed populations during pollination, respectively. No evidence for the pollen selection under acid rain stress was obtained in any of the test systems. Inhibition of protein synthesis using cycloheximide led to significant reduction of tube elongation at 4 hr and had no effect on pollen germination at any time interval tested. Total proteins extracted from control and acid rain stressed pollen grain populations exhibited no differences. The reduction of corn pollen germination in vitro under acid rain stress was mainly due to pollen rupture. The present data indicates the reduction of pollen germination and tube growth under acid rain stress may be a physiological response rather than a genetic response. A simple, nontoxic, and effective method to separate germinated from ungerminated pollen grains has been developed using pollen from corn (Zea mays, L. cv. Pioneer 3747). The separated germinated pollen grains retained viability and continued tube growth when placed in culture medium.« less

Higher Temperature at Lower Elevation Sites Fails to Promote Acclimation or Adaptation to Heat Stress During Pollen Germination.

PubMed

Flores-Rentería, Lluvia; Whipple, Amy V; Benally, Gilbert J; Patterson, Adair; Canyon, Brandon; Gehring, Catherine A

2018-01-01

High temperatures associated with climate change are expected to be detrimental for aspects of plant reproduction, such as pollen viability. We hypothesized that (1) higher peak temperatures predicted with climate change would have a minimal effect on pollen viability, while high temperatures during pollen germination would negatively affect pollen viability, (2) high temperatures during pollen dispersal would facilitate acclimation to high temperatures during pollen germination, and (3) pollen from populations at sites with warmer average temperatures would be better adapted to high temperature peaks. We tested these hypotheses in Pinus edulis , a species with demonstrated sensitivity to climate change, using populations along an elevational gradient. We tested for acclimation to high temperatures by measuring pollen viability during dispersal and germination stages in pollen subjected to 30, 35, and 40°C in a factorial design. We also characterized pollen phenology and measured pollen heat tolerance using trees from nine sites along a 200 m elevational gradient that varied 4°C in temperature. We demonstrated that this gradient is biologically meaningful by evaluating variation in vegetation composition and P. edulis performance. Male reproduction was negatively affected by high temperatures, with stronger effects during pollen germination than pollen dispersal. Populations along the elevational gradient varied in pollen phenology, vegetation composition, plant water stress, nutrient availability, and plant growth. In contrast to our hypothesis, pollen viability was highest in pinyons from mid-elevation sites rather than from lower elevation sites. We found no evidence of acclimation or adaptation of pollen to high temperatures. Maximal plant performance as measured by growth did not occur at the same elevation as maximal pollen viability. These results indicate that periods of high temperature negatively affected sexual reproduction, such that even high pollen production may not result in successful fertilization due to low germination. Acquired thermotolerance might not limit these impacts, but pinyon could avoid heat stress by phenological adjustment of pollen development. Higher pollen viability at the core of the distribution could be explained by an optimal combination of biotic and abiotic environmental factors. The disconnect between measures of growth and pollen production suggests that vigor metrics may not accurately estimate reproduction.

Recombinant Mal d 1 facilitates sublingual challenge tests of birch pollen-allergic patients with apple allergy.

PubMed

Kinaciyan, T; Nagl, B; Faustmann, S; Kopp, S; Wolkersdorfer, M; Bohle, B

2016-02-01

It is still unclear whether allergen-specific immunotherapy (AIT) with birch pollen improves birch pollen-related food allergy. One reason for this may be the lack of standardized tests to assess clinical reactions to birch pollen-related foods, for example apple. We tested the applicability of recombinant (r) Mal d 1, the Bet v 1-homolog in apple, for oral challenge tests. Increasing concentrations of rMal d 1 in 0.9% NaCl were sublingually administered to 72 birch pollen-allergic patients with apple allergy. The dose of 1.6 μg induced oral allergy syndromes in 26.4%, 3.2 μg in 15.3%, 6.3 μg in 27.8%, 12.5 μg in 8.3%, 25 μg in 11.1%, and 50 μg in 4.2% of the patients. No severe reactions occurred. None of the patients reacted to 0.9% NaCl alone. Sublingual administration of 50 μg of rMal d 1 induced no reactions in three nonallergic individuals. Our approach allows straight forward, dose-defined sublingual challenge tests in a high number of birch pollen-allergic patients that inter alia can be applied to evaluate the therapeutic efficacy of birch pollen AIT on birch pollen-related food allergy. © 2015 The Authors. Allergy Published by John Wiley & Sons Ltd.

Allergenic pollen season variations in the past two decades under changing climate in the United States

PubMed Central

Zhang, Yong; Bielory, Leonard; Mi, Zhongyuan; Cai, Ting; Robock, Alan; Georgopoulos, Panos

2014-01-01

Many diseases are linked with climate trends and variations. In particular, climate change is expected to alter the spatiotemporal dynamics of allergenic airborne pollen and potentially increase occurrence of allergic airway disease. Understanding the spatiotemporal patterns of changes in pollen season timing and levels is thus important in assessing climate impacts on aerobiology and allergy caused by allergenic airborne pollen. Here we describe the spatiotemporal patterns of changes in the seasonal timing and levels of allergenic airborne pollen for multiple taxa in different climate regions at a continental scale. The allergenic pollen seasons of representative trees, weeds and grass during the past decade (2001–2010) across the contiguous United States have been observed to start 3.0 (95% Confidence Interval (CI), 1.1–4.9) days earlier on average than in the 1990s (1994–2000). The average peak value and annual total of daily counted airborne pollen have increased by 42.4% (95% CI, 21.9%–62.9%) and 46.0% (95% CI, 21.5%–70.5%), respectively. Changes of pollen season timing and airborne levels depend on latitude, and are associated with changes of growing degree days, frost free days, and precipitation. These changes are likely due to recent climate change and particularly the enhanced warming and precipitation at higher latitudes in the contiguous United States. PMID:25266307

[Does a lateral gradient of membrane potential on the plasma membrane of growing pollen tube of germinating pollen grain exist?].

PubMed

Andreev, I M

2011-01-01

The data presented in the article by Breigina et al. (2009) "Changes in the membrane potential during pollen grain germination and pollen tube growth" (Tsitologiya. 51 (10): 815-823) and concerning the measurement of electric membrane potential (Delta Psi) on the plasma membrane of growing pollen tube of germinating pollen grain with the use of fluorescent potential-sensitive dye, di-4-ANEPPS, were critically analyzed in order to clarify whether a lateral gradient of Delta Psi on this membrane indeed exists. This analysis showed that the main conclusion of the authors of the above article on the existence of polar distribution of Delta Psi along the pollen tube plasma membrane is not in accordance with a number of known peculiarities of di-4-ANEPPS behavior in biological membranes and requires a significant revision. The findings in question reported by the authors, in my opinion, might be interpreted as evidence for the presence on the plasma membrane of growing pollen tube not only the membrane potential Delta Psi but also lateral gradient of so called intra-membrane dipole potential. Based on the comments made, another interpretation of the experimental results described by Breigina et al. has been offered. In addition, some drawbacks in the methodology used by the authors for measurement of Delta Psi with other fluorescent potential-sensitive dye, DiBAC3(3), are also shortly considered.

Water status and associated processes mark critical stages in pollen development and functioning.

PubMed

Firon, Nurit; Nepi, Massimo; Pacini, Ettore

2012-06-01

The male gametophyte developmental programme can be divided into five phases which differ in relation to the environment and pollen hydration state: (1) pollen develops inside the anther immersed in locular fluid, which conveys substances from the mother plant--the microsporogenesis phase; (2) locular fluid disappears by reabsorption and/or evaporation before the anther opens and the maturing pollen grains undergo dehydration--the dehydration phase; (3) the anther opens and pollen may be dispersed immediately, or be held by, for example, pollenkitt (as occurs in almost all entomophilous species) for later dispersion--the presentation phase; (4) pollen is dispersed by different agents, remaining exposed to the environment for different periods--the dispersal phase; and (5) pollen lands on a stigma and, in the case of a compatible stigma and suitable conditions, undergoes rehydration and starts germination--the pollen-stigma interaction phase. This review highlights the issue of pollen water status and indicates the various mechanisms used by pollen grains during their five developmental phases to adjust to changes in water content and maintain internal stability. Pollen water status is co-ordinated through structural, physiological and molecular mechanisms. The structural components participating in regulation of the pollen water level, during both dehydration and rehydration, include the exine (the outer wall of the pollen grain) and the vacuole. Recent data suggest the involvement of water channels in pollen water transport and the existence of several molecular mechanisms for pollen osmoregulation and to protect cellular components (proteins and membranes) under water stress. It is suggested that pollen grains will use these mechanisms, which have a developmental role, to cope with environmental stress conditions.

Identification and persistence of Pinus pollen DNA on cotton fabrics: A forensic application.

PubMed

Schield, Cassandra; Campelli, Cassandra; Sycalik, Jennifer; Randle, Christopher; Hughes-Stamm, Sheree; Gangitano, David

2016-01-01

Advances in plant genomics have had an impact on the field of forensic botany. However, the use of pollen DNA profiling in forensic investigations has yet to be applied. Five volunteers wore a jacket with Pinus echinata pollen-containing cotton swatches for a 14-day period. Pollen decay was evaluated at days 0, 3, 6, 9 and 14 by microscopy. Pollen grains were then transferred to slides using a portable forensic vacuum handle. Ten single grains per swatch were isolated for DNA analysis. DNA was extracted using a high throughput extraction method. A nine-locus short tandem repeat (STR) multiplex system, including previously published primers from Pinus taeda, was developed. DNA was amplified by PCR using fluorescent dyes and analyzed by capillary electrophoresis. Pollen counts from cotton swatches in a 14-day period exhibited an exponential decay from 100% to 17%. The success rate of PCR amplification was 81.2%. Complete and partial STR profiles were generated from 250 pollen grains analyzed (44% and 37%, respectively). Due to the limited amount of DNA, drop-in events were observed (1.87%). However, the rate of contamination with pollen from other pine individuals originating from environmental sources was 4.4%. In conclusion, this study has shown that pollen can be a stable source of forensic DNA evidence, as a proof-of-principle, and that may persist on cotton clothing for at least 14 days of wear. This method can be applied in forensic cases where pollen grains larger than 10 μm (e.g., from herbs or trees) may be transferred to clothing (worn by suspect or victim) by primary contact. Copyright © 2015 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.

Dynamics of post-translationally modified histones during barley pollen embryogenesis in the presence or absence of the epi-drug trichostatin A.

PubMed

Pandey, Pooja; Daghma, Diaa S; Houben, Andreas; Kumlehn, Jochen; Melzer, Michael; Rutten, Twan

2017-06-01

Improving pollen embryogenesis. Despite the agro-economic importance of pollen embryogenesis, the mechanisms underlying this process are still poorly understood. We describe the dynamics of chromatin modifications (histones H3K4me2, H3K9ac, H3K9me2, and H3K27me3) and chromatin marks (RNA polymerase II CDC phospho-Ser5, and CENH3) during barley pollen embryogenesis. Immunolabeling results show that, in reaction to stress, immature pollen rapidly starts reorganizing several important chromatin modifications indicative of a change in cell fate. This new chromatin modification pattern was accomplished within 24 h from whereon it remained unaltered during subsequent mitotic activity. This indicates that cell fate transition, the central element of pollen embryogenesis, is completed early on during the induction process. Application of the histone deacetylase inhibitor trichostatin A stimulated pollen embryogenesis when used on pollen with a gametophytic style chromatin pattern. However, when this drug was administered to embryogenic pollen, the chromatin markers reversed toward a gametophytic profile, embryogenesis was halted and all pollen invariably died.

Epidermal jasmonate perception is sufficient for all aspects of jasmonate-mediated male fertility in Arabidopsis.

PubMed

Jewell, Jeremy B; Browse, John

2016-03-01

Jasmonate (JA) signaling is essential for several environmental responses and reproductive development in many plant species. In Arabidopsis thaliana, the most obvious phenotype of JA biosynthetic and perception mutants is profound sporophytic male sterility characterized by failure of stamen filament elongation, severe delay of anther dehiscence and pollen inviability. The site of action of JA in the context of reproductive development has been discussed, but the ideas have not been tested experimentally. To this end we used targeted expression of a COI1-YFP transgene in the coi1-1 mutant background. As COI1 is an essential component of the JA co-receptor complex, the null coi1-1 mutant is male sterile due to lack of JA perception. We show that expression of COI1-YFP in the epidermis of the stamen filament and anther in coi1 mutant plants is sufficient to rescue filament elongation, anther dehiscence and pollen viability. In contrast, filament expression alone or expression in the tapetum do not restore dehiscence and pollen viability. These results demonstrate that epidermal JA perception is sufficient for anther function and pollen viability, and suggest the presence of a JA-dependent non-autonomous signal produced in the anther epidermis to synchronize both anther dehiscence and pollen maturation. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Empirical, Metagenomic, and Computational Techniques Illuminate the Mechanisms by which Fungicides Compromise Bee Health.

PubMed

Steffan, Shawn A; Dharampal, Prarthana S; Diaz-Garcia, Luis; Currie, Cameron R; Zalapa, Juan; Hittinger, Chris Todd

2017-10-09

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered "bee-safe," there is mounting evidence that fungicide residues in pollen are associated with bee declines (for both honey and bumble bee species). While the mechanisms remain relatively unknown, researchers have speculated that bee-microbe symbioses are involved. Microbes play a pivotal role in the preservation and/or processing of pollen, which serves as nutrition for larval bees. By altering the microbial community, it is likely that fungicides disrupt these microbe-mediated services, and thereby compromise bee health. This manuscript describes the protocols used to investigate the indirect mechanism(s) by which fungicides may be causing colony decline. Cage experiments exposing bees to fungicide-treated flowers have already provided the first evidence that fungicides cause profound colony losses in a native bumble bee (Bombus impatiens). Using field-relevant doses of fungicides, a series of experiments have been developed to provide a finer description of microbial community dynamics of fungicide-exposed pollen. Shifts in the structural composition of fungal and bacterial assemblages within the pollen microbiome are investigated by next-generation sequencing and metagenomic analysis. Experiments developed herein have been designed to provide a mechanistic understanding of how fungicides affect the microbiome of pollen-provisions. Ultimately, these findings should shed light on the indirect pathway through which fungicides may be causing colony declines.

Impacts of oak pollen on allergic asthma in the United States and potential influence of future climate change

EPA Science Inventory

Oak pollen season length for moderate (RCP4.5) and severe climate change scenarios (RCP8.5) are estimated through 2090 using five climate models and published relationships between temperature, precipitation, and oak pollen season length. We calculated asthma ED visit counts asso...

Short term effects of airborne pollen concentrations on asthma epidemic

PubMed Central

Tobias, A; Galan, I; Banegas, J; Aranguez, E

2003-01-01

Methods: This study, based on time series analysis adjusting for meteorological factors and air pollution variables, assessed the short term effects of different types of allergenic pollen on asthma hospital emergencies in the metropolitan area of Madrid (Spain) for the period 1995–8. Results: Statistically significant associations were found for Poaceae pollen (lag of 3 days) and Plantago pollen (lag of 2 days), representing an increase in the range between the 99th and 95th percentiles of 17.1% (95% confidence interval (CI) 3.2 to 32.8) and 15.9% (95% CI 6.5 to 26.2) for Poaceae and Plantago, respectively. A positive association was also observed for Urticaceae (lag of 1 day) with an 8.4% increase (95% CI 2.8 to 14.4). Conclusions: There is an association between pollen levels and asthma related emergencies, independent of the effect of air pollutants. The marked relationship observed for Poaceae and Plantago pollens suggests their implication in the epidemic distribution of asthma during the period coinciding with their abrupt release into the environment. PMID:12885991

[Preliminary study on the effect of climate factors on pollen fertility in Platycodon grandiflorum].

PubMed

Shi, Feng-hua; Zhang, Lei; Wei, Jian-he

2011-06-01

To have a better utilization of male sterile lines in heterozygotic breeding of Platycodon grandiflorum and provide theoretical basis for Platycodon grandiflorum hyboridization. The pollen viability was detected by the means of aceto carmine dyeing, and the correlation analysis between climate factors of each anther development stage and pollen viability was estimated by Pearson coefficients. Pollen viability variation range of male-sterile line GP1BC1-12 was 0% - 27%. That of male-sterile line GP12BC4-10 and chifeng germplasm was respectively 1.3% - 17.9% and 75.9% - 98.5%. Further linear regression analysis between climate factors of each anther development stage and pollen viability indicated that the degree of sensitivity varied with different germplasm of Platycodon grandiflorum. Among three germplasm, male sterile line GP12BC4-10 was the most stable one to the climate factors, and the male-sterile line GP1BC1-12 was the most sensitive one. Temperature and solar irradiation are the most important climate factors to affect pollen viability in Platycodon grandflorum, and microspore mother cells stage (MMC) is its sensetive stage.

Microbial characterization of bee pollen from the Vesuvius area collected by using three different traps.

PubMed

Mauriello, Gianluigi; De Prisco, Annachiara; Di Prisco, Gennaro; La Storia, Antonietta; Caprio, Emilio

2017-01-01

Flower pollen is collected by honeybee foragers, adhered on their rear legs and transported into the hives in the form of pellets. Once in the hives, bee pollen is moisturised with nectar and bee mouth secretions and due to enzymatically modifications it becomes the so-called bee-bread, the protein reservoir of young bees. Bee pollen can be artificially removed from bee legs and collected by using specific systems, the bee pollen traps. Bee pollen is commercialized for human consumption as fresh product and after freezing or drying. Although bee pollen is nowadays largely consumed in developed countries, as food or food supplement according to local legislation, little is known on its safety related to microbiological hazards. In this work, we aimed to characterize for the first time the microbiological profile of Italian bee pollen in fresh, frozen and dried form collected along an entire harvesting season. Moreover, monthly microbiological analyses were performed on frozen (storage at -18°C) and dried (storage at room temperature) bee pollen over a 4 months period. Further aim of this work was the evaluation of the possible impact on production level of three different traps used for pollen collection. Our results on microbial contamination of fresh and frozen bee pollen show that a more comprehensive microbiological risk assessment of bee pollen is required. On the other side, dried pollen showed very low microbial contamination and no pathogen survived after the drying process and during storage.

Microbial characterization of bee pollen from the Vesuvius area collected by using three different traps

PubMed Central

De Prisco, Annachiara; Di Prisco, Gennaro; La Storia, Antonietta; Caprio, Emilio

2017-01-01

Flower pollen is collected by honeybee foragers, adhered on their rear legs and transported into the hives in the form of pellets. Once in the hives, bee pollen is moisturised with nectar and bee mouth secretions and due to enzymatically modifications it becomes the so-called bee-bread, the protein reservoir of young bees. Bee pollen can be artificially removed from bee legs and collected by using specific systems, the bee pollen traps. Bee pollen is commercialized for human consumption as fresh product and after freezing or drying. Although bee pollen is nowadays largely consumed in developed countries, as food or food supplement according to local legislation, little is known on its safety related to microbiological hazards. In this work, we aimed to characterize for the first time the microbiological profile of Italian bee pollen in fresh, frozen and dried form collected along an entire harvesting season. Moreover, monthly microbiological analyses were performed on frozen (storage at -18°C) and dried (storage at room temperature) bee pollen over a 4 months period. Further aim of this work was the evaluation of the possible impact on production level of three different traps used for pollen collection. Our results on microbial contamination of fresh and frozen bee pollen show that a more comprehensive microbiological risk assessment of bee pollen is required. On the other side, dried pollen showed very low microbial contamination and no pathogen survived after the drying process and during storage. PMID:28934240

Organismal versus Environmental Control of the Carbon Isotope Composition of Dicot Angiosperm Pollen: Implications for Paleoenvironmental Reconstruction

NASA Astrophysics Data System (ADS)

King, D. P.; Schubert, B.; Foelber, K.; Jahren, H.

2011-12-01

The prevalence and diagenetic resilience of palynomorphs in Proterozoic and Phanerozoic sediments has led researchers to investigate its potential as an environmental proxy based on its stable isotope composition. Towards this, Loader and Hemming (2001), noted that the carbon isotope composition (δ13C) of modern Pinus sylvestris pollen exine correlates with the developmental period temperature (°C) of the pollen (R2=0.68), implying that the δ13C of gymnosperm pollen could be quantitatively utilized as a paleotemperature proxy. However, the majority of pollen-producing organisms during the last ~120 million years have been angiosperms, which are subject to complex internal signaling for reproduction, in addition to environmental triggers. Because these internal signals control the relative proportion of lipids, long-chain fatty acids, and polysaccharides within pollen grains, we hypothesized that the δ13C variability in pollen (δ13Cpollen) from several plants subject to the same external environmental parameters is of the same magnitude as the amount attributed to the environment for gymnosperms. Within growth chambers, the test organism (Brassica rapa) was cultivated under constant light, water, pCO2, and nutrient supply, but exhibited average δ13Cpollen variability = 4.35% within any chamber (n = 6 to 8 plants per chamber). Field experiments were also conducted in which the pollen from the test organism (Hibiscus spp.) was sampled from several botanical gardens within the state of Hawaii. Pollen collected from any one botanical garden exhibited an average δ13Cpollen variability = 4.5% (up to 5 plants per garden). Upon comparing chambers operating at different temperatures (17°C to 32°C), we discovered no correlation (R2=0.01) between the developmental period temperature (°C) and the δ13C of B. rapa pollen; similarly, no correlation was found between the δ13C of Hibiscus pollen and its developmental period temperature (°C) (R2=0.12). This work underscores the lack of consistent environmental control over the δ13C value of pollen, and suggests that the carbon isotope composition of dicot pollen cannot be used to determine paleotemperatures. Future work centers on our hypothesis that the δ13C variability in angiosperm pollen results from differential reproductive potency and associated differences in the percentages of lipids, long-chain fatty acids, and polysaccharides within pollen. Towards this we will quantify the relationship between the chemical composition of flower-aggregate pollen and its δ13C value, given the δ13C value of isolated end-member constituents.

Fluctuations in the East Asian monsoon recorded by pollen assemblages in sediments from the Japan Sea off the southwestern coast of Hokkaido, Japan, from 4.3 Ma to the present

NASA Astrophysics Data System (ADS)

Igarashi, Yaeko; Irino, Tomohisa; Sawada, Ken; Song, Lu; Furota, Satoshi

2018-04-01

We reconstructed fluctuations in the East Asian monsoon and vegetation in the Japan Sea region since the middle Pliocene based on pollen data obtained from sediments collected by the Integrated Ocean Drilling Program off the southwestern coast of northern Japan. Taxodiaceae conifers Metasequoia and Cryptomeria and Sciadopityacere conifer Sciadopitys are excellent indicators of a humid climate during the monsoon. The pollen temperature index (Tp) can be used as a proxy for relative air temperature. Based on changes in vegetation and reconstructed climate over a period of 4.3 Ma, we classified the sediment sequence into six pollen zones. From 4.3 to 3.8 Ma (Zone 1), the climate fluctuated between cool/moist and warm/moist climatic conditions. Vegetation changed between warm temperate mixed forest and cool temperate conifer forest. The Neogene type tree Carya recovered under a warm/moist climate. The period from 3.8 to 2.5 Ma (Zone 2) was characterized by increased Metasequoia pollen concentration. Warm temperate mixed forest vegetation developed under a cool/moist climate. The period from 2.5 to 2.2 Ma (Zone 3) was characterized by an abrupt increase in Metasequoia and/or Cryptomeria pollen and a decrease in warm broadleaf tree pollen, indicating a cool/humid climate. The Zone 4 period (2.2-1.7 Ma) was characterized by a decrease in Metasequoia and/or Cryptomeria pollen and an increase in cool temperate conifer Picea and Tsuga pollen, indicating a cool/moist climate. The period from 1.7 to 0.3 Ma (Zone 5) was characterized by orbital-scale climate fluctuations. Cycles of abrupt increases and decreases in Cryptomeria and Picea pollen and in Tp values indicated changes between warm/humid and cold/dry climates. The alpine fern Selaginella selaginoides appeared as of 1.6 Ma. Vegetation alternated among warm mixed, cool mixed, and cool temperate conifer forests. Zone 6 (0.3 Ma to present) was characterized by a decrease in Cryptomeria pollen. The warm temperate broadleaf forest and cool temperate conifer forest developed alternately under warm/moist and cold/dry climate. Zone 2 corresponded to a weak Tsushima Current breaking through the Tsushima Strait, and the beginning of orbital-scale climatic changes at 1.7 Ma during Zone 5 corresponded to the strong inflow of the Tsushima Current into the Japan Sea during interglacial periods (Gallagher et al., 2015).

Evidence that a herbivore tolerance response affects selection on floral traits and inflorescence architecture in purple loosestrife (Lythrum salicaria)

PubMed Central

Sargent, Risa D.

2017-01-01

Abstract Background and Aims The study of the evolution of floral traits has generally focused on pollination as the primary driver of selection. However, herbivores can also impose selection on floral traits through a variety of mechanisms, including florivory and parasitism. Less well understood is whether floral and inflorescence architecture traits that influence a plant’s tolerance to herbivory, such as compensatory regrowth, alter pollinator-mediated selection. Methods Because herbivore damage to Lythrum salicaria meristems typically leads to an increase in the number of inflorescences and the size of the floral display, an experiment was conducted to test whether simulated herbivory (i.e. clipping the developing meristem) could alter the magnitude or direction of pollinator-mediated selection on a suite of floral and inflorescence architecture traits. Using a pollen supplementation protocol, pollen limitation was compared in the presence and absence of meristem damage in order to quantify any interaction between pollinator and herbivore-mediated selection on floral traits. Key Results Surprisingly, in spite of an obvious impact on floral display and architecture, with clipped plants producing more inflorescences and more flowers, there was no difference in pollen limitation between clipped and unclipped plants. Correspondingly, there was no evidence that imposing herbivore damage altered pollinator-mediated selection in this system. Rather, the herbivory treatment alone was found to alter direct selection on floral display, with clipped plants experiencing greater selection for earlier flowering and weaker selection for number of inflorescences when compared with unclipped plants. Conclusions These findings imply that herbivory on its own can drive selection on plant floral traits and inflorescence architecture in this species, even more so than pollinators. Specifically, herbivory can impose selection on floral traits if such traits influence a plant’s tolerance to herbivory, such as through the timing of flowering and/or the compensatory regrowth response. PMID:28369263

Water status and associated processes mark critical stages in pollen development and functioning

PubMed Central

Firon, Nurit; Nepi, Massimo; Pacini, Ettore

2012-01-01

Background The male gametophyte developmental programme can be divided into five phases which differ in relation to the environment and pollen hydration state: (1) pollen develops inside the anther immersed in locular fluid, which conveys substances from the mother plant – the microsporogenesis phase; (2) locular fluid disappears by reabsorption and/or evaporation before the anther opens and the maturing pollen grains undergo dehydration – the dehydration phase; (3) the anther opens and pollen may be dispersed immediately, or be held by, for example, pollenkitt (as occurs in almost all entomophilous species) for later dispersion – the presentation phase; (4) pollen is dispersed by different agents, remaining exposed to the environment for different periods – the dispersal phase; and (5) pollen lands on a stigma and, in the case of a compatible stigma and suitable conditions, undergoes rehydration and starts germination – the pollen–stigma interaction phase. Scope This review highlights the issue of pollen water status and indicates the various mechanisms used by pollen grains during their five developmental phases to adjust to changes in water content and maintain internal stability. Conclusions Pollen water status is co-ordinated through structural, physiological and molecular mechanisms. The structural components participating in regulation of the pollen water level, during both dehydration and rehydration, include the exine (the outer wall of the pollen grain) and the vacuole. Recent data suggest the involvement of water channels in pollen water transport and the existence of several molecular mechanisms for pollen osmoregulation and to protect cellular components (proteins and membranes) under water stress. It is suggested that pollen grains will use these mechanisms, which have a developmental role, to cope with environmental stress conditions. PMID:22523424

Class XI Myosins Move Specific Organelles in Pollen Tubes and Are Required for Normal Fertility and Pollen Tube Growth in Arabidopsis1[OPEN

PubMed Central

Madison, Stephanie L.; Buchanan, Matthew L.; Glass, Jeremiah D.; McClain, Tarah F.; Park, Eunsook; Nebenführ, Andreas

2015-01-01

Pollen tube growth is an essential aspect of plant reproduction because it is the mechanism through which nonmotile sperm cells are delivered to ovules, thus allowing fertilization to occur. A pollen tube is a single cell that only grows at the tip, and this tip growth has been shown to depend on actin filaments. It is generally assumed that myosin-driven movements along these actin filaments are required to sustain the high growth rates of pollen tubes. We tested this conjecture by examining seed set, pollen fitness, and pollen tube growth for knockout mutants of five of the six myosin XI genes expressed in pollen of Arabidopsis (Arabidopsis thaliana). Single mutants had little or no reduction in overall fertility, whereas double mutants of highly similar pollen myosins had greater defects in pollen tube growth. In particular, myo11c1 myo11c2 pollen tubes grew more slowly than wild-type pollen tubes, which resulted in reduced fitness compared with the wild type and a drastic reduction in seed set. Golgi stack and peroxisome movements were also significantly reduced, and actin filaments were less organized in myo11c1 myo11c2 pollen tubes. Interestingly, the movement of yellow fluorescent protein-RabA4d-labeled vesicles and their accumulation at pollen tube tips were not affected in the myo11c1 myo11c2 double mutant, demonstrating functional specialization among myosin isoforms. We conclude that class XI myosins are required for organelle motility, actin organization, and optimal growth of pollen tubes. PMID:26358416

Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand.

PubMed

Medek, Danielle E; Beggs, Paul J; Erbas, Bircan; Jaggard, Alison K; Campbell, Bradley C; Vicendese, Don; Johnston, Fay H; Godwin, Ian; Huete, Alfredo R; Green, Brett J; Burton, Pamela K; Bowman, David M J S; Newnham, Rewi M; Katelaris, Constance H; Haberle, Simon G; Newbigin, Ed; Davies, Janet M

2016-06-01

Although grass pollen is widely regarded as the major outdoor aeroallergen source in Australia and New Zealand (NZ), no assemblage of airborne pollen data for the region has been previously compiled. Grass pollen count data collected at 14 urban sites in Australia and NZ over periods ranging from 1 to 17 years were acquired, assembled and compared, revealing considerable spatiotemporal variability. Although direct comparison between these data is problematic due to methodological differences between monitoring sites, the following patterns are apparent. Grass pollen seasons tended to have more than one peak from tropics to latitudes of 37°S and single peaks at sites south of this latitude. A longer grass pollen season was therefore found at sites below 37°S, driven by later seasonal end dates for grass growth and flowering. Daily pollen counts increased with latitude; subtropical regions had seasons of both high intensity and long duration. At higher latitude sites, the single springtime grass pollen peak is potentially due to a cooler growing season and a predominance of pollen from C 3 grasses. The multiple peaks at lower latitude sites may be due to a warmer season and the predominance of pollen from C 4 grasses. Prevalence and duration of seasonal allergies may reflect the differing pollen seasons across Australia and NZ. It must be emphasized that these findings are tentative due to limitations in the available data, reinforcing the need to implement standardized pollen-monitoring methods across Australasia. Furthermore, spatiotemporal differences in grass pollen counts indicate that local, current, standardized pollen monitoring would assist with the management of pollen allergen exposure for patients at risk of allergic rhinitis and asthma.

Regional and seasonal variation in airborne grass pollen levels between cities of Australia and New Zealand

PubMed Central

Beggs, Paul J.; Erbas, Bircan; Jaggard, Alison K.; Campbell, Bradley C.; Vicendese, Don; Johnston, Fay H.; Godwin, Ian; Huete, Alfredo R.; Green, Brett J.; Burton, Pamela K.; Bowman, David M. J. S.; Newnham, Rewi M.; Katelaris, Constance H.; Haberle, Simon G.; Newbigin, Ed; Davies, Janet M.

2016-01-01

Although grass pollen is widely regarded as the major outdoor aeroallergen source in Australia and New Zealand (NZ), no assemblage of airborne pollen data for the region has been previously compiled. Grass pollen count data collected at 14 urban sites in Australia and NZ over periods ranging from 1 to 17 years were acquired, assembled and compared, revealing considerable spatiotemporal variability. Although direct comparison between these data is problematic due to methodological differences between monitoring sites, the following patterns are apparent. Grass pollen seasons tended to have more than one peak from tropics to latitudes of 37°S and single peaks at sites south of this latitude. A longer grass pollen season was therefore found at sites below 37°S, driven by later seasonal end dates for grass growth and flowering. Daily pollen counts increased with latitude; subtropical regions had seasons of both high intensity and long duration. At higher latitude sites, the single springtime grass pollen peak is potentially due to a cooler growing season and a predominance of pollen from C3 grasses. The multiple peaks at lower latitude sites may be due to a warmer season and the predominance of pollen from C4 grasses. Prevalence and duration of seasonal allergies may reflect the differing pollen seasons across Australia and NZ. It must be emphasized that these findings are tentative due to limitations in the available data, reinforcing the need to implement standardized pollen-monitoring methods across Australasia. Furthermore, spatiotemporal differences in grass pollen counts indicate that local, current, standardized pollen monitoring would assist with the management of pollen allergen exposure for patients at risk of allergic rhinitis and asthma. PMID:27069303

LONG DISTANCE POLLEN-MEDIATED GENE FLOW FROM CREEPING BENTGRASS

EPA Science Inventory

Researchers from USEPA WED have measured gene flow from experimental fields of Roundup? herbicide resistant genetically modified (GM) creeping bentgrass a grass used primarily on golf courses, to compatible non-crop relatives. Using a sampling design based on the estimated time ...

Acetylesterase-Mediated Deacetylation of Pectin Impairs Cell Elongation, Pollen Germination, and Plant Reproduction[C][W

PubMed Central

Gou, Jin-Ying; Miller, Lisa M.; Hou, Guichuan; Yu, Xiao-Hong; Chen, Xiao-Ya; Liu, Chang-Jun

2012-01-01

Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the level of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility. PMID:22247250

Acetylesterase-Mediated Deacetylation of Pectin Impairs Cell Elongation, Pollen Germination, and Plant Reproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gou J. Y.; Liu C.; Miller, L. M.

Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the levelmore » of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility.« less

The effect of oral honey and pollen on postoperative intraabdominal adhesions.

PubMed

Celeplı, Salih; Kismet, Kemal; Kaptanoğlu, Buğra; Erel, Serap; Ozer, Saadet; Celeplı, Pınar; Kaygusuz, Gülşah; Devrım, Erdinç; Gencay, Omür; Sorkun, Kadriye; Durak, Ilker; Akkuş, Mehmet Ali

2011-02-01

We evaluated the effect of oral usage of honey and pollen, either separately or together, on postoperative intraabdominal adhesions. Forty rats were randomly separated into 4 groups of 10 rats each. Abrasion was performed on the cecum, and a patch of peritoneum located opposite to the cecal abrasion was completely dissected. Group 1 rats received no treatment; Group 2 rats received 4 g/kg/day honey; Group 3 rats received 4 g/kg/day pollen; and Group 4 rats received 4 g/kg/day honey and pollen mixed in equal amounts, in addition to the standard feeding for postoperative 21 days. All the rats were sacrificed on the 21st day. Following the adhesion scoring, tissue specimens of the peritoneum and bowel were subjected to histopathological investigation. The tissue and blood specimens were also taken for biochemical analysis to investigate the antioxidant capacity. Adhesion scores were significantly different between the control and other groups. No dense adhesion was observed in the treatment groups. Tissue malondialdehyde levels were significantly different between the control and honey and honey+pollen groups. Superoxide dismutase and glutathione-peroxidase levels were significantly different between the control and other groups. Catalase levels were different between the control and honey groups. Plasma antioxidant levels were different between the control and other groups. The pathological scores for fibrosis and inflammation were significantly different between the control and other groups. Honey and pollen were found to be effective in preventing postoperative intraabdominal adhesions, and these effects were thought to be a result of their antiinflammatory and antioxidant properties.

Cross-reactivity and epitope analysis of Pru a 1, the major cherry allergen.

PubMed

Scheurer, S; Son, D Y; Boehm, M; Karamloo, F; Franke, S; Hoffmann, A; Haustein, D; Vieths, S

1999-02-01

A high percentage of birch pollen allergic patients experiences food hypersensivity after ingestion of fresh fruits and vegetables. The cross-reactivity of the major allergens of sweet cherry (Pru a 1), apple (Mal d 1), pear (Pyr c 1), celery tuber (Api g 1) and carrot (Dau c 1) is due to structural similarities which are reflected by high amino acid sequence identities with Bet v 1a, the major birch pollen allergen. Apart from a strong cross-reactivity to Bet v 1a, IgE inhibition experiments with Mal d 1, Pru a 1 and Api g 1 demonstrated the presence of common and different epitopes among the tested food allergens. Secondary structure prediction of all investigated allergens indicated the presence of almost identical structural elements. In particular, the 'P-loop' region is a common domain of the pollen related food allergens and of pathogenesis related proteins. To identify the IgE binding epitopes, five overlapping recombinant Pru a 1 fragments representing the entire amino acid sequence with lengths of approximately 60-120 residues were investigated. Weak IgE binding capacity was measured exclusively with Pru a IF4 (1-120) by immunoblotting, whereas none of the fragments showed allergenicity in the rat basophil leukaemia cell mediator release assay. Site-directed mutagenesis experiments with Pru a 1 revealed that amino acid S112 is critical for IgE binding of almost all patients sera tested. This reduced IgE binding was also observed with a single point mutant of Bet v 1a (S112P) and thus indicated serine 112 as an essential residue for preserving the structure of a cross-reactive IgE epitope. Moreover, two Pru a 1 mutants with an altered 'P-loop' region, showed a lowered IgE binding capacity for IgE from a subgroup of allergic patients. The investigation of essential features for preserving cross-reactive IgE-epitopes provides the structural basis for understanding the clinically observed cross-allergenicity between pollen and fruits. Moreover, non-anaphylactic allergen fragments or variants derived from the IgE-inducing pollen allergens may serve as useful tools for a new strategy of specific immunotherapy.

Rice No Pollen 1 (NP1) is required for anther cuticle formation and pollen exine patterning.

PubMed

Liu, Ze; Lin, Sen; Shi, Jianxin; Yu, Jing; Zhu, Lu; Yang, Xiujuan; Zhang, Dabing; Liang, Wanqi

2017-07-01

Angiosperm male reproductive organs (anthers and pollen grains) have complex and interesting morphological features, but mechanisms that underlie their patterning are poorly understood. Here we report the isolation and characterization of a male sterile mutant of No Pollen 1 (NP1) in rice (Oryza sativa). The np1-4 mutant exhibited smaller anthers with a smooth cuticle surface, abnormal Ubisch bodies, and aborted pollen grains covered with irregular exine. Wild-type exine has two continuous layers; but np1-4 exine showed a discontinuous structure with large granules of varying size. Chemical analysis revealed reduction in most of the cutin monomers in np1-4 anthers, and less cuticular wax. Map-based cloning suggested that NP1 encodes a putative glucose-methanol-choline oxidoreductase; and expression analyses found NP1 preferentially expressed in the tapetal layer from stage 8 to stage 10 of anther development. Additionally, the expression of several genes involved in biosynthesis and in the transport of lipid monomers of sporopollenin and cutin was decreased in np1-4 mutant anthers. Taken together, these observations suggest that NP1 is required for anther cuticle formation, and for patterning of Ubisch bodies and the exine. We propose that products of NP1 are likely important metabolites in the development of Ubisch bodies and pollen exine, necessary for polymerization, assembly, or both. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Mycobiota and mycotoxins in bee pollen collected from different areas of Slovakia.

PubMed

Kačániová, Miroslava; Juráček, Miroslav; Chlebo, Róbert; Kňazovická, Vladimíra; Kadasi-Horáková, Miriam; Kunová, Simona; Lejková, Jadža; Haščík, Peter; Mareček, Ján; Simko, Milan

2011-01-01

Contamination by microscopic fungi and mycotoxins in different bee pollen samples, which were stored under three different ways of storing as freezing, drying and UV radiation, was investigated. During spring 2009, 45 samples of bee-collected pollen were gathered from beekeepers who placed their bee colonies on monocultures of sunflower, rape and poppy fields within their flying distance. Bee pollen was collected from bees' legs by special devices placed at the entrance to hives. Samples were examined for the concentration and identification of microscopic fungi able to grow on Malt and Czapek-Dox agar and mycotoxins content [deoxynivalenol (DON), T-2 toxin (T-2), zearalenone (ZON) and total aflatoxins (AFL), fumonisins (FUM), ochratoxins (OTA)] by direct competitive enzyme-linked immunosorbent assays (ELISA). The total number of microscopic fungi in this study ranged from 2.98 ± 0.02 in frozen sunflower bee pollen to 4.06 ± 0.10 log cfu.g(-1) in sunflower bee pollen after UV radiation. In this study, 449 isolates belonging to 21 fungal species representing 9 genera were found in 45 samples of bee pollen. The total isolates were detected in frozen poppy pollen 29, rape pollen 40, sunflower pollen 80, in dried poppy pollen 12, rape pollen 36, sunflower 78, in poppy pollen after UV radiation treatment 54, rape 59 and sunflower 58. The most frequent isolates of microscopic fungi found in bee pollen samples of all prevalent species were Mucor mucedo (49 isolates), Alternaria alternata (40 isolates), Mucor hiemalis (40 isolates), Aspergillus fumigatus (33 isolates) and Cladosporium cladosporioides (31 isolates). The most frequently found isolates were detected in sunflower bee pollen frozen (80 isolates) and the lowest number of isolates was observed in poppy bee pollen dried (12 isolates). The most prevalent mycotoxin of poppy bee pollen was ZON (361.55 ± 0.26 μg.kg(-1)), in rape bee pollen T-2 toxin (265.40 ± 0.18 μg.kg(-1)) and in sunflower bee pollen T-2 toxin (364.72 ± 0.13 μg.kg(-1)) in all cases in frozen samples.

Pollen exposure and hospitalization due to asthma exacerbations: daily time series in a European city.

PubMed

Osborne, Nicholas J; Alcock, Ian; Wheeler, Benedict W; Hajat, Shakoor; Sarran, Christophe; Clewlow, Yolanda; McInnes, Rachel N; Hemming, Deborah; White, Mathew; Vardoulakis, Sotiris; Fleming, Lora E

2017-10-01

Exposure to pollen can contribute to increased hospital admissions for asthma exacerbation. This study applied an ecological time series analysis to examine associations between atmospheric concentrations of different pollen types and the risk of hospitalization for asthma in London from 2005 to 2011. The analysis examined short-term associations between daily pollen counts and hospital admissions in the presence of seasonal and long-term patterns, and allowed for time lags between exposure and admission. Models were adjusted for temperature, precipitation, humidity, day of week, and air pollutants. Analyses revealed an association between daily counts (continuous) of grass pollen and adult hospital admissions for asthma in London, with a 4-5-day lag. When grass pollen concentrations were categorized into Met Office pollen 'alert' levels, 'very high' days (vs. 'low') were associated with increased admissions 2-5 days later, peaking at an incidence rate ratio of 1.46 (95%, CI 1.20-1.78) at 3 days. Increased admissions were also associated with 'high' versus 'low' pollen days at a 3-day lag. Results from tree pollen models were inconclusive and likely to have been affected by the shorter pollen seasons and consequent limited number of observation days with higher tree pollen concentrations. Future reductions in asthma hospitalizations may be achieved by better understanding of environmental risks, informing improved alert systems and supporting patients to take preventive measures.

Pollen exposure and hospitalization due to asthma exacerbations: daily time series in a European city

NASA Astrophysics Data System (ADS)

Osborne, Nicholas J.; Alcock, Ian; Wheeler, Benedict W.; Hajat, Shakoor; Sarran, Christophe; Clewlow, Yolanda; McInnes, Rachel N.; Hemming, Deborah; White, Mathew; Vardoulakis, Sotiris; Fleming, Lora E.

2017-10-01

Exposure to pollen can contribute to increased hospital admissions for asthma exacerbation. This study applied an ecological time series analysis to examine associations between atmospheric concentrations of different pollen types and the risk of hospitalization for asthma in London from 2005 to 2011. The analysis examined short-term associations between daily pollen counts and hospital admissions in the presence of seasonal and long-term patterns, and allowed for time lags between exposure and admission. Models were adjusted for temperature, precipitation, humidity, day of week, and air pollutants. Analyses revealed an association between daily counts (continuous) of grass pollen and adult hospital admissions for asthma in London, with a 4-5-day lag. When grass pollen concentrations were categorized into Met Office pollen `alert' levels, `very high' days (vs. `low') were associated with increased admissions 2-5 days later, peaking at an incidence rate ratio of 1.46 (95%, CI 1.20-1.78) at 3 days. Increased admissions were also associated with `high' versus `low' pollen days at a 3-day lag. Results from tree pollen models were inconclusive and likely to have been affected by the shorter pollen seasons and consequent limited number of observation days with higher tree pollen concentrations. Future reductions in asthma hospitalizations may be achieved by better understanding of environmental risks, informing improved alert systems and supporting patients to take preventive measures.

A novel experimental technology for testing efficacy of air purifiers on pollen reduction.

PubMed

Bergmann, Karl-Christian; Sehlinger, Torsten; Gildemeister, Julia; Zuberbier, Torsten

2017-01-01

Allergenic pollen exposure is mostly seen as an outdoor phenomenon but studies have shown an indoor exposure: different pollen species including birch and grass pollen in houses, schools, and shops are leading to long-lasting symptoms even after the pollen season because pollen settle on surfaces and re-enter the indoor air depending on ventilation. To reduce indoor pollen load, windows need to be closed and devices should be used: as pure wiping and cleaning of surfaces is mostly not sufficient, air cleaners may be helpful in reducing pollen counts in indoor environment. The efficacy of an air cleaner is usually described by the filtration rate of standard dust particle sizes which is not necessarily related to clinical efficacy. A novel study design was developed using the technical equipment of a new mobile exposure chamber to investigate participants with allergic rhinitis (individual observational, controlled, prospective, single arm study). The tested air cleaner reduced the grass pollen-induced (4000 grass pollen/m 3 over 90 min) nasal symptoms (total nasal symptom score) significantly from 6 and 4 points (1st and 2nd exposure in sham run) to less than 1 point when air cleaner was activated. The novel study protocol is suitable for testing efficacy of air cleaners and the tested air cleaner is effective in reducing clinical symptoms due to grass pollen in an indoor environment.

The weak effects of climatic change on Plantago pollen concentration: 17 years of monitoring in Northwestern Spain.

PubMed

González-Parrado, Zulima; Valencia-Barrera, Rosa Ma; Vega-Maray, Ana Ma; Fuertes-Rodríguez, Carmen Reyes; Fernández-González, Delia

2014-09-01

Plantago L. species are very common in nitrified areas such as roadsides and their pollen is a major cause of pollinosis in temperate regions. In this study, we sampled airborne pollen grains in the city of León (NW, Spain) from January 1995 to December 2011, by using a Burkard® 7-day-recording trap. The percentage of Plantago pollen compared to the total pollen count ranged from 11% (1997) to 3% (2006) in the period under study. Peak pollen concentrations were recorded in May and June. Our 17-year analysis failed to disclose significant changes in the seasonal trend of plantain pollen concentration. In addition, there were no important changes in the start dates of pollen release and the meteorological parameters analyzed did not show significant variations in their usual trends. We analyzed the influence of several meteorological parameters on Plantago pollen concentration to explain the differences in pollen concentration trends during the study. Our results show that temperature, sun hours, evaporation, and relative humidity are the meteorological parameters best correlated to the behavior of Plantago pollen grains. In general, the years with low pollen concentrations correspond to the years with less precipitation or higher temperatures. We calculated the approximate Plantago flowering dates using the cumulative sum of daily maximum temperatures and compared them with the real bloom dates. The differences obtained were 4 days in 2009, 3 days in 2010, and 1 day in 2011 considering the complete period of pollination.

The weak effects of climatic change on Plantago pollen concentration: 17 years of monitoring in Northwestern Spain

NASA Astrophysics Data System (ADS)

González-Parrado, Zulima; Valencia-Barrera, Rosa Ma.; Vega-Maray, Ana Ma.; Fuertes-Rodríguez, Carmen Reyes; Fernández-González, Delia

2014-09-01

Plantago L. species are very common in nitrified areas such as roadsides and their pollen is a major cause of pollinosis in temperate regions. In this study, we sampled airborne pollen grains in the city of León (NW, Spain) from January 1995 to December 2011, by using a Burkard® 7-day-recording trap. The percentage of Plantago pollen compared to the total pollen count ranged from 11 % (1997) to 3 % (2006) in the period under study. Peak pollen concentrations were recorded in May and June. Our 17-year analysis failed to disclose significant changes in the seasonal trend of plantain pollen concentration. In addition, there were no important changes in the start dates of pollen release and the meteorological parameters analyzed did not show significant variations in their usual trends. We analyzed the influence of several meteorological parameters on Plantago pollen concentration to explain the differences in pollen concentration trends during the study. Our results show that temperature, sun hours, evaporation, and relative humidity are the meteorological parameters best correlated to the behavior of Plantago pollen grains. In general, the years with low pollen concentrations correspond to the years with less precipitation or higher temperatures. We calculated the approximate Plantago flowering dates using the cumulative sum of daily maximum temperatures and compared them with the real bloom dates. The differences obtained were 4 days in 2009, 3 days in 2010, and 1 day in 2011 considering the complete period of pollination.

PsPMEP, a pollen-specific pectin methylesterase of pea (Pisum sativum L.).

PubMed

Gómez, María Dolores; Renau-Morata, Begoña; Roque, Edelín; Polaina, Julio; Beltrán, José Pío; Cañas, Luis A

2013-09-01

Pectin methylesterases (PMEs) are a family of enzymes involved in plant reproductive processes such as pollen development and pollen tube growth. We have isolated and characterized PsPMEP, a pea (Pisum sativum L.) pollen-specific gene that encodes a protein with homology to PMEs. Sequence analysis showed that PsPMEP belongs to group 2 PMEs, which are characterized by the presence of a processable amino-terminal PME inhibitor domain followed by the catalytic PME domain. Moreover, PsPMEP contains several motifs highly conserved among PMEs with the essential amino acid residues involved in enzyme substrate binding and catalysis. Northern blot and in situ hybridization analyses showed that PsPMEP is expressed in pollen grains from 4 days before anthesis till anther dehiscence and in pollinated carpels. In the PsPMEP promoter region, we have identified several conserved cis-regulatory elements that have been associated with gene pollen-specific expression. Expression analysis of PsPMEP promoter fused to the uidA reporter gene in Arabidopsis thaliana plants showed a similar expression pattern when compared with pea, indicating that this promoter is also functional in a non-leguminous plant. GUS expression was detected in mature pollen grains, during pollen germination, during pollen tube elongation along the transmitting tract, and when the pollen tube reaches the embryo sac in the ovule.

Development of a guideline on vegetation area to reduce the risk of weed pollinosis in Korea

NASA Astrophysics Data System (ADS)

Rang Kim, Kyu; Lee, Hye-Rim; Kim, Mijin; Baek, Won-ki; Oh, Jae-Won; Choi, Young-Jean; Jung, Hyun-Sook

2013-04-01

Allergenic pollens are influenced by the environmental conditions so that the daily number of pollens varies by temperature, humidity, wind speed, etc. The relationship between the daily pollens and meteorological conditions were determined and utilized to forecast daily risk level of pollen allergy in Korea. Another important factor for the daily risk level of pollens is the vegetation area of the allergenic plants. In this study, the relationship between the area and pollen concentration was identified for two major weed species: Ragweed and Japanese Hop. It was then utilized to determine the upper limit of vegetation area to confine the risk level to a certain degree in the field. Three sites with different levels of pollen concentration were selected among twelve pollen observation sites in Korea based on the historical observation of the weed pollens. The vegetation area of the two weed species within four square kilometers at each site was surveyed. The maximum daily pollen concentration was highly correlated with the vegetation area and it was selected as a dependent variable for the regression equations, which were used as the guideline for vegetation area. According to the guideline, to limit the maximum daily pollen concentration under the moderate risk level or less than 50 pollen grains per cubic meter for Ragweed, the vegetation area should remain less than 0.6% of the ground area. For the moderate risk of Japanese Hop, pollen grains should be limited less than 100 and the area be less than 0.4%.

A biology-driven receptor model for daily pollen allergy risk in Korea based on Weibull probability density function

NASA Astrophysics Data System (ADS)

Kim, Kyu Rang; Kim, Mijin; Choe, Ho-Seong; Han, Mae Ja; Lee, Hye-Rim; Oh, Jae-Won; Kim, Baek-Jo

2017-02-01

Pollen is an important cause of respiratory allergic reactions. As individual sanitation has improved, allergy risk has increased, and this trend is expected to continue due to climate change. Atmospheric pollen concentration is highly influenced by weather conditions. Regression analysis and modeling of the relationships between airborne pollen concentrations and weather conditions were performed to analyze and forecast pollen conditions. Traditionally, daily pollen concentration has been estimated using regression models that describe the relationships between observed pollen concentrations and weather conditions. These models were able to forecast daily concentrations at the sites of observation, but lacked broader spatial applicability beyond those sites. To overcome this limitation, an integrated modeling scheme was developed that is designed to represent the underlying processes of pollen production and distribution. A maximum potential for airborne pollen is first determined using the Weibull probability density function. Then, daily pollen concentration is estimated using multiple regression models. Daily risk grade levels are determined based on the risk criteria used in Korea. The mean percentages of agreement between the observed and estimated levels were 81.4-88.2 % and 92.5-98.5 % for oak and Japanese hop pollens, respectively. The new models estimated daily pollen risk more accurately than the original statistical models because of the newly integrated biological response curves. Although they overestimated seasonal mean concentration, they did not simulate all of the peak concentrations. This issue would be resolved by adding more variables that affect the prevalence and internal maturity of pollens.

A biology-driven receptor model for daily pollen allergy risk in Korea based on Weibull probability density function.

PubMed

Kim, Kyu Rang; Kim, Mijin; Choe, Ho-Seong; Han, Mae Ja; Lee, Hye-Rim; Oh, Jae-Won; Kim, Baek-Jo

2017-02-01

Pollen is an important cause of respiratory allergic reactions. As individual sanitation has improved, allergy risk has increased, and this trend is expected to continue due to climate change. Atmospheric pollen concentration is highly influenced by weather conditions. Regression analysis and modeling of the relationships between airborne pollen concentrations and weather conditions were performed to analyze and forecast pollen conditions. Traditionally, daily pollen concentration has been estimated using regression models that describe the relationships between observed pollen concentrations and weather conditions. These models were able to forecast daily concentrations at the sites of observation, but lacked broader spatial applicability beyond those sites. To overcome this limitation, an integrated modeling scheme was developed that is designed to represent the underlying processes of pollen production and distribution. A maximum potential for airborne pollen is first determined using the Weibull probability density function. Then, daily pollen concentration is estimated using multiple regression models. Daily risk grade levels are determined based on the risk criteria used in Korea. The mean percentages of agreement between the observed and estimated levels were 81.4-88.2 % and 92.5-98.5 % for oak and Japanese hop pollens, respectively. The new models estimated daily pollen risk more accurately than the original statistical models because of the newly integrated biological response curves. Although they overestimated seasonal mean concentration, they did not simulate all of the peak concentrations. This issue would be resolved by adding more variables that affect the prevalence and internal maturity of pollens.

Macronutrient ratios in pollen shape bumble bee (Bombus impatiens) foraging strategies and floral preferences

PubMed Central

Vaudo, Anthony D.; Patch, Harland M.; Mortensen, David A.; Tooker, John F.; Grozinger, Christina M.

2016-01-01

To fuel their activities and rear their offspring, foraging bees must obtain a sufficient quality and quantity of nutritional resources from a diverse plant community. Pollen is the primary source of proteins and lipids for bees, and the concentrations of these nutrients in pollen can vary widely among host-plant species. Therefore we hypothesized that foraging decisions of bumble bees are driven by both the protein and lipid content of pollen. By successively reducing environmental and floral cues, we analyzed pollen-foraging preferences of Bombus impatiens in (i) host-plant species, (ii) pollen isolated from these host-plant species, and (iii) nutritionally modified single-source pollen diets encompassing a range of protein and lipid concentrations. In our semifield experiments, B. impatiens foragers exponentially increased their foraging rates of pollen from plant species with high protein:lipid (P:L) ratios; the most preferred plant species had the highest ratio (∼4.6:1). These preferences were confirmed in cage studies where, in pairwise comparisons in the absence of other floral cues, B. impatiens workers still preferred pollen with higher P:L ratios. Finally, when presented with nutritionally modified pollen, workers were most attracted to pollen with P:L ratios of 5:1 and 10:1, but increasing the protein or lipid concentration (while leaving ratios intact) reduced attraction. Thus, macronutritional ratios appear to be a primary factor driving bee pollen-foraging behavior and may explain observed patterns of host-plant visitation across the landscape. The nutritional quality of pollen resources should be taken into consideration when designing conservation habitats supporting bee populations. PMID:27357683

[An analysis of spectrum of allergen sensitization among patients with tree pollen allergy in Beijing].

PubMed

Wang, X Y; Ning, H Y; Chu, S M; Jiang, L; Pang, Y J; Jin, W T; Wang, S Q; Wang, X Y

2017-12-05

Objective: To explore the feature of allergic sensitization of tree pollen and the relationship between tree pollen and airborne pollen in Beijing. Method: Two thousand five hundred and twenty-one patients with allergic diseases were enrolled between January to July in 2017 in an allergy department. All patients received SPT of 8 kinds of tree pollen. Result: ①The overall tree pollen positive rate of SPT was 49.3% (1 244/2 521). Male had a higher positive rate than female (56.4% vs 45.0%, P <0.01) while child group had a higher positive rate than adult group (55.9% vs 48.6%, P <0.05). The poly sensitization was observed with a rate of 26.3%, take the percentage of 53.3% of the overall positive subjects. ②The highest sensitization rate was found in March (62.2%), followed by May (52.1%), the lowest was January (27.9%). There was a positive correlation between tree pollen sensitization rate and pollen count of each month ( r =0.929, P <0.01). ③Cypress had the highest positive rate (34.6%), followed by poplar (21.3%), the lowest was sophora (13.3%). The sensitization rate was positively correlated with pollen count among different tree pollen ( r =0.714, P <0.05). Conclusion: The main allergic pollen in Beijing was cypress. The tree pollen sensitization showed a seasonality with the peak in March. The sensitization status was tightly associated with the amount of airborne pollen. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

[Prediction of the total Japanese cedar pollen counts based on male flower-setting conditions of standard trees].

PubMed

Yuta, Atsushi; Ukai, Kotaro; Sakakura, Yasuo; Tani, Hideshi; Matsuda, Fukiko; Yang, Tian-qun; Majima, Yuichi

2002-07-01

We made a prediction of the Japanese cedar (Cryptomeria japonica) pollen counts at Tsu city based on male flower-setting conditions of standard trees. The 69 standard trees from 23 kinds of clones, planted at Mie Prefecture Science and Technology Promotion Center (Hakusan, Mie) in 1964, were selected. Male flower-setting conditions for 276 faces (69 trees x 4 points of the compass) were scored from 0 to 3. The average of scores and total pollen counts from 1988 to 2000 was analyzed. As the results, the average scores from standard trees and total pollen counts except two mass pollen-scattered years in 1995 and 2000 had a positive correlation (r = 0.914) by linear function. On the mass pollen-scattered years, pollen counts were influenced from the previous year. Therefore, the score of the present year minus that of the previous year were used for analysis. The average scores from male flower-setting conditions and pollen counts had a strong positive correlation (r = 0.994) when positive scores by taking account of the previous year were analyzed. We conclude that prediction of pollen counts are possible based on the male flower-setting conditions of standard trees.

Coincidence of pollen season with the first fetal trimester together with early pet exposure is associated with sensitization to cat and dog allergens in early childhood: A Finnish population-based study.

PubMed

Pyrhönen, K; Kulmala, P; Näyhä, S

2018-03-01

Children whose 11th fetal week falls in pollen season (spring) reportedly have an increased risk of sensitization to food allergens. No such finding has been reported for pet allergens. The aim of the study was to (i) evaluate the incidence of pet (dog and cat) sensitization according to the season of the 11th fetal week and (ii) whether the association between pet exposure and respective sensitization is modified by the coincidence of the 11th fetal week with pollen season. The study population comprised all children (born between 2001 and 2006) in the province of South Karelia, Finland (N = 5920). Their data of immunoglobulin E antibodies and skin prick tests to pet allergens (N = 538) were collected from patient records and linked with questionnaire data on pet exposure. The seasonal incidence peak of cat sensitization was observed in children whose 11th fetal week occurred in June (7.4%) and that of dog sensitization in April (3.8%) and June (4.7%). The relative rate (RR) for cat sensitization was 2.92 (95% CI 1.40-6.08) in children with cat exposure alone, 8.53 (4.07-17.86) in children with cat and fetal pollen exposures and 0.61 (0.20-1.83) in children exposed to pollen alone, compared with children without these exposures. The respective RRs for dog sensitization were 2.17 (1.13-4.19), 4.40 (2.19-8.83) and 1.65 (0.77-3.53). Coincidence of the first fetal trimester with pollen season strengthens the association between pet exposure and respective sensitization. Pollen exposure at early pregnancy may deviate immune system towards Th2-type reactivity promoting development of specific allergy in case allergen exposure occurred. Therefore, primary prevention of allergic diseases may need to begin during early pregnancy. © 2017 John Wiley & Sons Ltd.

Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease

PubMed Central

Zhang, Rui; Duhl, Tiffany; Salam, Muhammad T.; House, James M.; Flagan, Richard C.; Avol, Edward L.; Gilliland, Frank D.; Guenther, Alex; Chung, Serena H.; Lamb, Brian K.; VanReken, Timothy M.

2014-01-01

Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD) in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the WRF/CMAQ air-quality modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS) model was used to generate a daily pollen pool that can then be emitted into the atmosphere by wind. The STaMPS is driven by species-specific meteorological (temperature and/or precipitation) threshold conditions and is designed to be flexible with respect to its representation of vegetation species and plant functional types (PFTs). The hourly pollen emission flux was parameterized by considering the pollen pool, friction velocity, and wind threshold values. The dry deposition velocity of each species of pollen was estimated based on pollen grain size and density. An evaluation of the pollen modeling framework was conducted for southern California for the period from March to June 2010. This period coincided with observations by the University of Southern California's Children's Health Study (CHS), which included O3, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nesting domains with horizontal resolutions of 12 km and 4 km were constructed, and six representative allergenic pollen genera were included: birch tree, walnut tree, mulberry tree, olive tree, oak tree, and brome grasses. Under the current parameterization scheme, the modeling framework tends to underestimate walnut and peak oak pollen concentrations, and tends to overestimate grass pollen concentrations. The model shows reasonable agreement with observed birch, olive, and mulberry tree pollen concentrations. Sensitivity studies suggest that the estimation of the pollen pool is a major source of uncertainty for simulated pollen concentrations. Achieving agreement between emission modeling and observed pattern of pollen releases is the key for successful pollen concentration simulations. PMID:24839448

Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease

NASA Astrophysics Data System (ADS)

Zhang, R.; Duhl, T.; Salam, M. T.; House, J. M.; Flagan, R. C.; Avol, E. L.; Gilliland, F. D.; Guenther, A.; Chung, S. H.; Lamb, B. K.; VanReken, T. M.

2013-03-01

Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD) in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the WRF/CMAQ air-quality modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS) model was used to generate a daily pollen pool that can then be emitted into the atmosphere by wind. The STaMPS is driven by species-specific meteorological (temperature and/or precipitation) threshold conditions and is designed to be flexible with respect to its representation vegetation species and plant functional types (PFTs). The hourly pollen emission flux was parameterized by considering the pollen pool, friction velocity, and wind threshold values. The dry deposition velocity of each species of pollen was estimated based on pollen grain size and density. An evaluation of the pollen modeling framework was conducted for southern California for the period from March to June 2010. This period coincided with observations by the University of Southern California's Children's Health Study (CHS), which included O3, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nesting domains with horizontal resolutions of 12 km and 4 km were constructed, and six representative allergenic pollen genera were included: birch tree, walnut tree, mulberry tree, olive tree, oak tree, and brome grasses. Under the current parameterization scheme, the modeling framework tends to underestimate walnut and peak oak pollen concentrations, and tends to overestimate grass pollen concentrations. The model shows reasonable agreement with observed birch, olive, and mulberry tree pollen concentrations. Sensitivity studies suggest that the estimation of the pollen pool is a major source of uncertainty for simulated pollen concentrations. Achieving agreement between emission modeling and observed pattern of pollen releases is the key for successful pollen concentration simulations.

Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease

NASA Astrophysics Data System (ADS)

Zhang, R.; Duhl, T.; Salam, M. T.; House, J. M.; Flagan, R. C.; Avol, E. L.; Gilliland, F. D.; Guenther, A.; Chung, S. H.; Lamb, B. K.; VanReken, T. M.

2014-03-01

Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD) in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the coupled Weather Research and Forecasting Community Multiscale Air Quality (WRF/CMAQ) modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS) model was used to generate a daily pollen pool that can then be emitted into the atmosphere by wind. The STaMPS is driven by species-specific meteorological (temperature and/or precipitation) threshold conditions and is designed to be flexible with respect to its representation of vegetation species and plant functional types (PFTs). The hourly pollen emission flux was parameterized by considering the pollen pool, friction velocity, and wind threshold values. The dry deposition velocity of each species of pollen was estimated based on pollen grain size and density. An evaluation of the pollen modeling framework was conducted for southern California (USA) for the period from March to June 2010. This period coincided with observations by the University of Southern California's Children's Health Study (CHS), which included O3, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nesting domains with horizontal resolutions of 12 and 4 km were constructed, and six representative allergenic pollen genera were included: birch tree, walnut tree, mulberry tree, olive tree, oak tree, and brome grasses. Under the current parameterization scheme, the modeling framework tends to underestimate walnut and peak oak pollen concentrations, and tends to overestimate grass pollen concentrations. The model shows reasonable agreement with observed birch, olive, and mulberry tree pollen concentrations. Sensitivity studies suggest that the estimation of the pollen pool is a major source of uncertainty for simulated pollen concentrations. Achieving agreement between emission modeling and observed pattern of pollen releases is the key for successful pollen concentration simulations.

Pollen counts and their relationship to meteorological factors in Ankara, Turkey during 2005-2008.

PubMed

Kizilpinar, Ilginc; Civelek, Ersoy; Tuncer, Ayfer; Dogan, Cahit; Karabulut, Erdem; Sahiner, Umit M; Yavuz, S Tolga; Sackesen, Cansin

2011-07-01

Pollen plays an important role in the development and exacerbation of allergic diseases. We aimed to investigate the days with highest counts of the most allergenic pollens and to identify the meteorological factors affecting pollen counts in the atmosphere of Ankara, Turkey. Airborne pollen measurements were carried out from 2005 to 2008 with a Burkard volumetric 7-day spore trap. Microscope counts were converted into atmospheric concentrations and expressed as pollen grains/m(3). Meteorological parameters were obtained from the State Meteorological Service. All statistical analyses were done with pollen counts obtained from March to October for each year. The percentages of tree, grass and weed pollens were 72.1% (n = 24,923), 12.8% (n = 4,433) and 15.1% (n = 5,219), respectively. The Pinaceae family from tree taxa (39% to 57%) and the Chenopodiaceae/Amaranthaceae family from weed taxa, contributed the highest percentage of pollen (25% to 43%), while from the grass taxa, only the Poaceae family was detected from 2005 to 2008. Poaceae and Chenopodiaceae/Amaranthaceae families, which are the most allergenic pollens, were found in high numbers from May to August in Ankara. In multiple logistic regression analysis, wind speed (OR = 1.18, CI95% = 1.02-1.36, P = 0.023) for tree pollen, daily mean temperature (OR = 1.10, CI95% = 1.04-1.17, P = 0.001) and sunshine hours (OR = 1.15, CI95% = 1.01-1.30, P = 0.033) for grass pollen, and sunshine hours (OR = 3.79, CI95% = 1.03-13.92, P = 0.044) for weed pollen were found as significant risk factors for high pollen count. The pollen calendar and its association with meteorological factors depend mainly on daily temperature, sunshine hours and wind speed, which may help draw the attention of physicians and allergic patients to days with high pollen counts.

Pollen counts and their relationship to meteorological factors in Ankara, Turkey during 2005-2008

NASA Astrophysics Data System (ADS)

Kizilpinar, Ilginc; Civelek, Ersoy; Tuncer, Ayfer; Dogan, Cahit; Karabulut, Erdem; Sahiner, Umit M.; Yavuz, S. Tolga; Sackesen, Cansin

2011-07-01

Pollen plays an important role in the development and exacerbation of allergic diseases. We aimed to investigate the days with highest counts of the most allergenic pollens and to identify the meteorological factors affecting pollen counts in the atmosphere of Ankara, Turkey. Airborne pollen measurements were carried out from 2005 to 2008 with a Burkard volumetric 7-day spore trap. Microscope counts were converted into atmospheric concentrations and expressed as pollen grains/m3. Meteorological parameters were obtained from the State Meteorological Service. All statistical analyses were done with pollen counts obtained from March to October for each year. The percentages of tree, grass and weed pollens were 72.1% ( n = 24,923), 12.8% ( n = 4,433) and 15.1% ( n = 5,219), respectively. The Pinaceae family from tree taxa (39% to 57%) and the Chenopodiaceae/Amaranthaceae family from weed taxa, contributed the highest percentage of pollen (25% to 43%), while from the grass taxa, only the Poaceae family was detected from 2005 to 2008. Poaceae and Chenopodiaceae/Amaranthaceae families, which are the most allergenic pollens, were found in high numbers from May to August in Ankara. In multiple logistic regression analysis, wind speed (OR = 1.18, CI95% = 1.02-1.36, P = 0.023) for tree pollen, daily mean temperature (OR = 1.10, CI95% = 1.04-1.17, P = 0.001) and sunshine hours (OR = 1.15, CI95% = 1.01-1.30, P = 0.033) for grass pollen, and sunshine hours (OR = 3.79, CI95% = 1.03-13.92, P = 0.044) for weed pollen were found as significant risk factors for high pollen count. The pollen calendar and its association with meteorological factors depend mainly on daily temperature, sunshine hours and wind speed, which may help draw the attention of physicians and allergic patients to days with high pollen counts.

Taxonomic description of in situ bee pollen from the middle Eocene of Germany.

PubMed

Grímsson, FriĐgeir; Zetter, Reinhard; Labandeira, Conrad C; Engel, Michael S; Wappler, Torsten

2017-01-02

The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees represent the earliest unambiguous records of their respective genera.

Taxonomic description of in situ bee pollen from the middle Eocene of Germany

PubMed Central

Grímsson, FriĐgeir; Zetter, Reinhard; Labandeira, Conrad C.; Engel, Michael S.; Wappler, Torsten

2017-01-01

Abstract The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees represent the earliest unambiguous records of their respective genera. PMID:28057943

Pollen Load and Flower Constancy of Three Species of Stingless Bees (Hymenoptera, Apidae, Meliponinae)

PubMed Central

Pangestika, Norita Widya; Atmowidi, Tri; Kahono, Sih

2017-01-01

The genera of stingless bees play an important role as pollinators of plants. These bees are actively involved in the pollination of agricultural crops and known to have preferences in selecting flowers to pollinate. The aims of this study were to analyse the pollen load and flower constancy in Tetragonula laeviceps, Lepidotrigona terminata, and Heterotrigona itama. Each individual of species stingless bees collected and was put in a 1.5 mL micro-tube contain 0.5 mL 70% ethanol:glycerol (4:1). Pollen loads on each individual of stingless bees was counted by hemocytometer. Flower constancy of stingless bees was measured based on percentage of pollen type loaded on the body. Results showed that the pollen loads of H. itama was the highest (31392 pollen grains) followed by L. terminata (23017 pollen grains) and T. laeviceps (8015 pollen grains). These species also demonstrated different flower constancy, T. laeviceps on Poaceae flowers (76.49%), L. terminata on Euphorbiaceae flowers (80.46%), and H. itama on Solanaceae flowers (83.33%). PMID:28890769

Seasonal allergic conjunctivitis induced by Japanese pear pollen.

PubMed

Yanagisawa, S; Nagaki, Y; Hiraki, S; Kadoi, C; Hayasaka, S; Teranishi, H

1999-01-01

To evaluate the ocular findings in patients with Japanese pear (Pyrus pyrifolia Nakai) pollinosis. Twenty-two farmers working on artificial pollination in Japanese pear orchards were examined for ocular itching, conjunctival conditions, presence of eosinophils in the conjunctival specimen, and nasal symptoms. Serum IgE antibody to Japanese pear pollen was determined in 16 farmers. Of the 22 subjects, 3 (Nos. 3, 4, and 13) exhibited ocular itching, conjunctival hyperemia, eosinophils in the conjunctival specimen, and positive serum IgE antibodies to Japanese pear pollen. In these patients, the conjunctivitis disappeared after treatment with topical cromoglycate. The present study demonstrated that seasonal allergic conjunctivitis may be induced by Japanese pear pollen (entomophilous flower pollen).

Evaluating the efficacy of epinastine ophthalmic solution using a conjunctivitis allergen challenge model in patients with birch pollen allergic conjunctivitis.

PubMed

Tagawa, Yoshiaki; Namba, Kenichi; Nakazono, Yumi; Iwata, Daiju; Ishida, Susumu

2017-04-01

The efficacy of epinastine 0.05% ophthalmic solution for pollen allergic conjunctivitis has already been shown in a conjunctival allergen challenge (CAC) test using cedar pollen as a challenge. The present study investigated the efficacy of this solution against birch pollen conjunctivitis in a CAC test. Ten adult subjects (eight males and two females) with asymptomatic birch pollen conjunctivitis were enrolled in this study. The average age of the subjects was 41.1 years. This study was conducted during a period without birch pollen dispersion. In each subject, the epinastine 0.05% ophthalmic solution was instilled in one eye, and an artificial tear fluid was instilled in the fellow eye in a double-blind manner. Five minutes or 4 h after the drug instillation, both eyes were challenged with an optimal concentration of birch pollen, and ocular itching and conjunctival hyperemia were then graded. Tears were collected before the drug instillation and 20 min after the pollen challenge, and the histamine level was measured. The ocular itching scores and palpebral conjunctival hyperemia scores of the epinastine-treated eyes were significantly lower than those of the contralateral control eyes when the eyes were pretreated with the drug 4 h before the CAC. There was a significant correlation between the tear histamine level and mean ocular itching score of three time points (3, 5 and 10 min) following the CAC in the control eyes but not the epinastine-treated eyes. Epinastine is effective in suppressing ocular itching and conjunctival hyperemia in birch pollen conjunctivitis. Copyright © 2017 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

Efficacy evaluation of a pollen blocker cream against dust-mite allergy: A multicenter, randomized, double-blind, placebo-controlled crossover trial.

PubMed

Li, Yanqing; Cheng, Lei; Chen, Xiaoning; Yang, Beibei; Wang, Dehui

2015-01-01

To further evaluate the efficacy and safety of a pollen blocker cream against dust-mite allergy. A multicenter, randomized, double-blind, placebo-controlled, crossover trial was conducted in a Chinese population. Patients diagnosed with perennial allergic rhinitis, sensitive to dust-mite allergy including Dermatophagoides farinae and Dermatophagoides pteronyssinus were randomly allocated to receive a pollen blocker cream or placebo, which was applied and spread evenly to the lower internal nose region three times daily for a total of 30 days. The primary outcome measurements for efficacy were total nasal symptom score (TNSS) and individual nasal symptom score (iNSS). Adverse events were also monitored. After application of a pollen blocker, the mean TNSS decreased from 23.1 to 13.8, the decrease of the pollen blocker group (9.3) was highly significant compared with the placebo group (5.2; p < 0.001). Similarly, the decreases in iNSSs (rhinorrhea, congestion, sneezing, and itching) between the pollen blocker group and the placebo group were also significant (p < 0.05). In addition, in adults, the pollen blocker led to a remarkably significant decrease in TNSS (9.5) compared with placebo (5.4; p < 0.001); in children, the pollen blocker led to a significant decrease in TNSS (8.6) compared with placebo (4.8; p < 0.05). No statistical difference was found in the incidence of adverse events between the two groups (p > 0.05), and no severe systematic reactions were observed. Pollen Blocker is a safe and effective alternative to the drugs for treatment of AR, especially for Chinese people allergic to dust-mite allergy.

Association between first airborne cedar pollen level peak and pollinosis symptom onset: a web-based survey.

PubMed

Bando, Harumi; Sugiura, Hiroaki; Ohkusa, Yasushi; Akahane, Manabu; Sano, Tomomi; Jojima, Noriko; Okabe, Nobuhiko; Imamura, Tomoaki

2015-01-01

Cedar pollinosis in Japan affects nearly 25 % of Japanese citizens. To develop a treatment for cedar pollinosis, it is necessary to understand the relationship between the time of its occurrence and the amount of airborne cedar pollen. In the spring of 2009, we conducted daily Internet-based epidemiologic surveys, which included 1453 individuals. We examined the relationship between initial date of onset of pollinosis symptoms and daily amount of airborne cedar pollen to which subjects were exposed. Approximately 35.2 % of the subjects experienced the onset of pollinosis during a one-week interval in which the middle day coincided with the peak pollen count. The odds ratio for this one-week time interval was 4.03 (95 % confidence interval: 3.34-4.86). The predicted date of the cedar pollen peak can be used to determine the appropriate date for initiation of self-medication with anti-allergy drugs and thus avoid development of sustained and severe pollinosis.

Intralymphatic allergen-specific immunotherapy: an effective and safe alternative treatment route for pollen-induced allergic rhinitis.

PubMed

Hylander, Terese; Latif, Leith; Petersson-Westin, Ulla; Cardell, Lars Olaf

2013-02-01

Allergen-specific immunotherapy is the only causative treatment of IgE-mediated allergic disorders. The most common administration route is subcutaneous, which may necessitate more than 50 allergen injections during 3 to 5 years. Recent evidence suggests that direct intralymphatic injections could yield faster beneficial results with considerably lower allergen doses and markedly reduced numbers of injections. To evaluate the effects of intralymphatic allergen-specific immunotherapy in pollen-allergic patients. In an open pilot investigation followed by a double-blind, placebo-controlled study, patients with allergic rhinitis were treated with 3 intralymphatic inguinal injections of ALK Alutard (containing 1000 SQ-U birch pollen or grass pollen) or placebo (ALK diluent). Clinical pre- and posttreatment parameters were assessed, the inflammatory cell content in nasal lavage fluids estimated, and the activation pattern of peripheral T cells described. All patients tolerated the intralymphatic immunotherapy (ILIT) treatment well, and the injections did not elicit any severe adverse event. Patients receiving active treatment displayed an initial increase in allergen-specific IgE level and peripheral T-cell activation. A clinical improvement in nasal allergic symptoms upon challenge was recorded along with a decreased inflammatory response in the nose. In addition, these patients reported an improvement in their seasonal allergic disease. No such changes were seen in the placebo group. Although this study is based on a limited number of patients, ILIT with grass-pollen or birch-pollen extracts appears to reduce nasal allergic symptoms without causing any safety problems. Hence, ILIT might constitute a less time-consuming and more cost-effective alternative to conventional subcutaneous allergen-specific immunotherapy. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Air-mediated pollen flow from genetically modified to conventional crops.

PubMed

Kuparinen, Anna; Schurr, Frank; Tackenberg, Oliver; O'Hara, Robert B

2007-03-01

Tools for estimating pollen dispersal and the resulting gene flow are necessary to assess the risk of gene flow from genetically modified (GM) to conventional fields, and to quantify the effectiveness of measures that may prevent such gene flow. A mechanistic simulation model is presented and used to simulate pollen dispersal by wind in different agricultural scenarios over realistic pollination periods. The relative importance of landscape-related variables such as isolation distance, topography, spatial configuration of the fields, GM field size and barrier, and environmental variation are examined in order to find ways to minimize gene flow and to detect possible risk factors. The simulations demonstrated a large variation in pollen dispersal and in the predicted amount of contamination between different pollination periods. This was largely due to variation in vertical wind. As this variation in wind conditions is difficult to control through management measures, it should be carefully considered when estimating the risk of gene flow from GM crops. On average, the predicted level of gene flow decreased with increasing isolation distance and with increasing depth of the conventional field, and increased with increasing GM field size. Therefore, at a national scale and over the long term these landscape properties should be accounted for when setting regulations for controlling gene flow. However, at the level of an individual field the level of gene flow may be dominated by uncontrollable variation. Due to the sensitivity of pollen dispersal to the wind, we conclude that gene flow cannot be summarized only by the mean contamination; information about the frequency of extreme events should also be considered. The modeling approach described in this paper offers a way to predict and compare pollen dispersal and gene flow in varying environmental conditions, and to assess the effectiveness of different management measures.

IgE reactivity to profilin in pollen-sensitized subjects with adverse reactions to banana and pineapple.

PubMed

Reindl, J; Rihs, H P; Scheurer, S; Wangorsch, A; Haustein, D; Vieths, S

2002-06-01

The so-called 'latex-fruit syndrome' is a well-documented phenomenon in cross-reactive allergies. By contrast, there is a lack of information about allergy to exotic fruits in patients with a predominant pollen sensitization. Since the ubiquitous protein profilin has been identified as an allergen in natural rubber latex as well as in pollen-related foods, the aim of this study was to investigate the role of profilin in allergy to certain exotic fruits. Recombinant profilins from banana and pineapple were cloned by a PCR technique after isolation of total RNA using degenerated profilin-specific primers. The unknown 5' ends of copy DNA (cDNA) were identified by rapid amplification of 5'cDNA ends (5'-RACE) and expression in Escherichia coli BL21(DE3) cells. The recombinant profilins were purified by affinity chromatography using poly-(L)-proline as the solid phase. IgE-binding capabilities were characterized by means of immunoblot and Enzyme Allergosorbent Test (EAST). The cross-reactivity to birch pollen profilin and latex profilin was studied by EAST as well as by immunoblot inhibition experiments. Both banana and pineapple profilin were found to consist of 131 amino acid residues with high amino acid sequence identity to known allergenic pollen and food profilins (71-84%). IgE binding to the recombinant profilins was observed in 7/16 sera from subjects with suspected banana allergy (44%) and in 8/19 sera from subjects with suspected pineapple allergy (42%). Inhibition experiments indicated similar IgE reactivity of natural and recombinant allergens. In addition, high cross-reactivity to birch pollen profilin Bet v 2 and latex profilin Hev b 8 was demonstrated by immunoblot inhibition as well as EAST inhibition experiments. Since a high IgE-binding prevalence of about 40% was obtained in both banana and pineapple allergy, we conclude that profilin is an important mediator of IgE cross-reactivity between pollen and exotic fruits. Copyright 2002 S. Karger AG, Basel

Pollen source effects on growth of kernel structures and embryo chemical compounds in maize.

PubMed

Tanaka, W; Mantese, A I; Maddonni, G A

2009-08-01

Previous studies have reported effects of pollen source on the oil concentration of maize (Zea mays) kernels through modifications to both the embryo/kernel ratio and embryo oil concentration. The present study expands upon previous analyses by addressing pollen source effects on the growth of kernel structures (i.e. pericarp, endosperm and embryo), allocation of embryo chemical constituents (i.e. oil, protein, starch and soluble sugars), and the anatomy and histology of the embryos. Maize kernels with different oil concentration were obtained from pollinations with two parental genotypes of contrasting oil concentration. The dynamics of the growth of kernel structures and allocation of embryo chemical constituents were analysed during the post-flowering period. Mature kernels were dissected to study the anatomy (embryonic axis and scutellum) and histology [cell number and cell size of the scutellums, presence of sub-cellular structures in scutellum tissue (starch granules, oil and protein bodies)] of the embryos. Plants of all crosses exhibited a similar kernel number and kernel weight. Pollen source modified neither the growth period of kernel structures, nor pericarp growth rate. By contrast, pollen source determined a trade-off between embryo and endosperm growth rates, which impacted on the embryo/kernel ratio of mature kernels. Modifications to the embryo size were mediated by scutellum cell number. Pollen source also affected (P < 0.01) allocation of embryo chemical compounds. Negative correlations among embryo oil concentration and those of starch (r = 0.98, P < 0.01) and soluble sugars (r = 0.95, P < 0.05) were found. Coincidently, embryos with low oil concentration had an increased (P < 0.05-0.10) scutellum cell area occupied by starch granules and fewer oil bodies. The effects of pollen source on both embryo/kernel ratio and allocation of embryo chemicals seems to be related to the early established sink strength (i.e. sink size and sink activity) of the embryos.

Genome-scale analysis and comparison of gene expression profiles in developing and germinated pollen in Oryza sativa

PubMed Central

2010-01-01

Background Pollen development from the microspore involves a series of coordinated cellular events, and the resulting mature pollen has a specialized function to quickly germinate, produce a polar-growth pollen tube derived from the vegetative cell, and deliver two sperm cells into the embryo sac for double fertilization. The gene expression profiles of developing and germinated pollen have been characterised by use of the eudicot model plant Arabidopsis. Rice, one of the most important cereal crops, has been used as an excellent monocot model. A comprehensive analysis of transcriptome profiles of developing and germinated pollen in rice is important to understand the conserved and diverse mechanism underlying pollen development and germination in eudicots and monocots. Results We used Affymetrix GeneChip® Rice Genome Array to comprehensively analyzed the dynamic changes in the transcriptomes of rice pollen at five sequential developmental stages from microspores to germinated pollen. Among the 51,279 transcripts on the array, we found 25,062 pollen-preferential transcripts, among which 2,203 were development stage-enriched. The diversity of transcripts decreased greatly from microspores to mature and germinated pollen, whereas the number of stage-enriched transcripts displayed a "U-type" change, with the lowest at the bicellular pollen stage; and a transition of overrepresented stage-enriched transcript groups associated with different functional categories, which indicates a shift in gene expression program at the bicellular pollen stage. About 54% of the now-annotated rice F-box protein genes were expressed preferentially in pollen. The transcriptome profile of germinated pollen was significantly and positively correlated with that of mature pollen. Analysis of expression profiles and coexpressed features of the pollen-preferential transcripts related to cell cycle, transcription, the ubiquitin/26S proteasome system, phytohormone signalling, the kinase system and defense/stress response revealed five expression patterns, which are compatible with changes in major cellular events during pollen development and germination. A comparison of pollen transcriptomes between rice and Arabidopsis revealed that 56.6% of the rice pollen preferential genes had homologs in Arabidopsis genome, but 63.4% of these homologs were expressed, with a small proportion being expressed preferentially, in Arabidopsis pollen. Rice and Arabidopsis pollen had non-conservative transcription factors each. Conclusions Our results demonstrated that rice pollen expressed a set of reduced but specific transcripts in comparison with vegetative tissues, and the number of stage-enriched transcripts displayed a "U-type" change during pollen development, with the lowest at the bicellular pollen stage. These features are conserved in rice and Arabidopsis. The shift in gene expression program at the bicellular pollen stage may be important to the transition from earlier cell division to later pollen maturity. Pollen at maturity pre-synthesized transcripts needed for germination and early pollen tube growth. The transcription regulation associated with pollen development would have divergence between the two species. Our results also provide novel insights into the molecular program and key components of the regulatory network regulating pollen development and germination. PMID:20507633

Exocyst SEC3 and Phosphoinositides Define Sites of Exocytosis in Pollen Tube Initiation and Growth1[OPEN

PubMed Central

Bloch, Daria; Pleskot, Roman; Vukašinović, Nemanja

2016-01-01

Polarized exocytosis is critical for pollen tube growth, but its localization and function are still under debate. The exocyst vesicle-tethering complex functions in polarized exocytosis. Here, we show that a sec3a exocyst subunit null mutant cannot be transmitted through the male gametophyte due to a defect in pollen tube growth. The green fluorescent protein (GFP)-SEC3a fusion protein is functional and accumulates at or proximal to the pollen tube tip plasma membrane. Partial complementation of sec3a resulted in the development of pollen with multiple tips, indicating that SEC3 is required to determine the site of pollen germination pore formation. Time-lapse imaging demonstrated that SEC3a and SEC8 were highly dynamic and that SEC3a localization on the apical plasma membrane predicts the direction of growth. At the tip, polar SEC3a domains coincided with cell wall deposition. Labeling of GFP-SEC3a-expressing pollen with the endocytic marker FM4-64 revealed the presence of subdomains on the apical membrane characterized by extensive exocytosis. In steady-state growing tobacco (Nicotiana tabacum) pollen tubes, SEC3a displayed amino-terminal Pleckstrin homology-like domain (SEC3a-N)-dependent subapical membrane localization. In agreement, SEC3a-N interacted with phosphoinositides in vitro and colocalized with a phosphatidylinositol 4,5-bisphosphate (PIP2) marker in pollen tubes. Correspondingly, molecular dynamics simulations indicated that SEC3a-N associates with the membrane by interacting with PIP2. However, the interaction with PIP2 is not required for polar localization and the function of SEC3a in Arabidopsis (Arabidopsis thaliana). Taken together, our findings indicate that SEC3a is a critical determinant of polar exocytosis during tip growth and suggest differential regulation of the exocytotic machinery depending on pollen tube growth modes. PMID:27516531

Exocyst SEC3 and Phosphoinositides Define Sites of Exocytosis in Pollen Tube Initiation and Growth.

PubMed

Bloch, Daria; Pleskot, Roman; Pejchar, Přemysl; Potocký, Martin; Trpkošová, Pavlína; Cwiklik, Lukasz; Vukašinović, Nemanja; Sternberg, Hasana; Yalovsky, Shaul; Žárský, Viktor

2016-10-01

Polarized exocytosis is critical for pollen tube growth, but its localization and function are still under debate. The exocyst vesicle-tethering complex functions in polarized exocytosis. Here, we show that a sec3a exocyst subunit null mutant cannot be transmitted through the male gametophyte due to a defect in pollen tube growth. The green fluorescent protein (GFP)-SEC3a fusion protein is functional and accumulates at or proximal to the pollen tube tip plasma membrane. Partial complementation of sec3a resulted in the development of pollen with multiple tips, indicating that SEC3 is required to determine the site of pollen germination pore formation. Time-lapse imaging demonstrated that SEC3a and SEC8 were highly dynamic and that SEC3a localization on the apical plasma membrane predicts the direction of growth. At the tip, polar SEC3a domains coincided with cell wall deposition. Labeling of GFP-SEC3a-expressing pollen with the endocytic marker FM4-64 revealed the presence of subdomains on the apical membrane characterized by extensive exocytosis. In steady-state growing tobacco (Nicotiana tabacum) pollen tubes, SEC3a displayed amino-terminal Pleckstrin homology-like domain (SEC3a-N)-dependent subapical membrane localization. In agreement, SEC3a-N interacted with phosphoinositides in vitro and colocalized with a phosphatidylinositol 4,5-bisphosphate (PIP 2 ) marker in pollen tubes. Correspondingly, molecular dynamics simulations indicated that SEC3a-N associates with the membrane by interacting with PIP 2 However, the interaction with PIP 2 is not required for polar localization and the function of SEC3a in Arabidopsis (Arabidopsis thaliana). Taken together, our findings indicate that SEC3a is a critical determinant of polar exocytosis during tip growth and suggest differential regulation of the exocytotic machinery depending on pollen tube growth modes. © 2016 American Society of Plant Biologists. All Rights Reserved.

An anther development F-box (ADF) protein regulated by tapetum degeneration retardation (TDR) controls rice anther development.

PubMed

Li, Li; Li, Yixing; Song, Shufeng; Deng, Huafeng; Li, Na; Fu, Xiqin; Chen, Guanghui; Yuan, Longping

2015-01-01

In this study, we reported that a F-box protein, OsADF, as one of the direct targets of TDR , plays a critical role in rice tapetum cell development and pollen formation. The tapetum, the innermost sporophytic tissue of anther, plays an important supportive role in male reproduction in flowering plants. After meiosis, tapetal cells undergo programmed cell death (PCD) and provide nutrients for pollen development. Previously we showed that tapetum degeneration retardation (TDR), a basic helix-loop-helix transcription factor, can trigger tapetal PCD and control pollen wall development during anther development. However, the comprehensive regulatory network of TDR remains to be investigated. In this study, we cloned and characterized a panicle-specific expression F-box protein, anther development F-box (OsADF). By qRT-PCR and RNA in situ hybridization, we further confirmed that OsADF expressed specially in tapetal cells from stage 9 to stage 12 during anther development. In consistent with this specific expression pattern, the RNAi transgenic lines of OsADF exhibited abnormal tapetal degeneration and aborted microspores development, which eventually grew pollens with reduced fertility. Furthermore, we demonstrated that the TDR, a key regulator in controlling rice anther development, could regulate directly the expression of OsADF by binding to E-box motifs of its promoter. Therefore, this work highlighted the possible regulatory role of TDR, which regulates tapetal cell development and pollen formation via triggering the possible ADF-mediated proteolysis pathway.

The ARC1 E3 ligase gene is frequently deleted in self-compatible Brassicaceae species and has a conserved role in Arabidopsis lyrata self-pollen rejection.

PubMed

Indriolo, Emily; Tharmapalan, Pirashaanthy; Wright, Stephen I; Goring, Daphne R

2012-11-01

Self-pollen rejection is an important reproductive regulator in flowering plants, and several different intercellular signaling systems have evolved to elicit this response. In the Brassicaceae, the self-incompatibility system is mediated by the pollen S-locus Cys-Rich/S-locus Protein11 (SCR/SP11) ligand and the pistil S Receptor Kinase (SRK). While the SCR/SP11-SRK recognition system has been identified in several species across the Brassicaceae, less is known about the conservation of the SRK-activated cellular responses in the stigma, following self-pollen contact. The ARM Repeat Containing1 (ARC1) E3 ubiquitin ligase functions downstream of SRK for the self-incompatibility response in Brassica, but it has been suggested that ARC1 is not required in Arabidopsis species. Here, we surveyed the presence of ARC1 orthologs in several recently sequenced genomes from Brassicaceae species that had diversified ∼20 to 40 million years ago. Surprisingly, the ARC1 gene was deleted in several species that had lost the self-incompatibility trait, suggesting that ARC1 may lose functionality in the transition to self-mating. To test the requirement of ARC1 in a self-incompatible Arabidopsis species, transgenic ARC1 RNA interference Arabidopsis lyrata plants were generated, and they exhibited reduced self-incompatibility responses resulting in successful fertilization. Thus, this study demonstrates a conserved role for ARC1 in the self-pollen rejection response within the Brassicaceae.

Allergy multivaccines created by DNA shuffling of tree pollen allergens.

PubMed

Wallner, Michael; Stöcklinger, Angelika; Thalhamer, Theresa; Bohle, Barbara; Vogel, Lothar; Briza, Peter; Breiteneder, Heimo; Vieths, Stefan; Hartl, Arnulf; Mari, Adriano; Ebner, Christof; Lackner, Peter; Hammerl, Peter; Thalhamer, Josef; Ferreira, Fatima

2007-08-01

The major allergens of trees belonging to the Fagales order are collectively known as the Bet v 1 family. Members of the Fagales order have distinct geographic distribution, and it is expected that depending on the exposure pattern of the individual, inclusion of other Bet v 1 family members might increase the efficacy of the treatment. We aimed to generate molecules that are suitable for specific immunotherapy not only against birch pollen allergy but also against allergies caused by other cross-reactive tree pollens. Fourteen genes of the Bet v 1 family were randomly recombined in vitro by means of DNA shuffling. This library of chimeric proteins was screened for molecules displaying low capacity to induce release of inflammatory mediators but with T-cell immunogenicity higher than that of the parental allergens. Two chimeric proteins were selected from the library of shuffled clones displaying low allergenicity and high immunogenicity, as determined in in vitro assays using human and animal cells and antibodies, as well as in vivo in animal models of allergy. Our results show that it is possible to randomly recombine in vitro T- and B-cell epitopes of a family of related allergens and to select chimeric proteins that perfectly match the criteria presently thought to be relevant for improving allergen-specific immunotherapy. The hypoallergenic chimeras described here recombine epitopes of the major Fagales pollen allergens and thus can efficiently substitute a mixture of extracts used for treating patients with tree pollen-induced spring pollinosis worldwide.

Resilient plant-bird interactions in a volcanic island ecosystem: pollination of Japanese Camellia mediated by the Japanese White-eye.

PubMed

Abe, Harue; Ueno, Saneyoshi; Takahashi, Toshimori; Tsumura, Yoshihiko; Hasegawa, Masami

2013-01-01

Observations of interspecies interactions during volcanic activity provide important opportunities to study how organisms respond to environmental devastation. Japanese camellia (Camellia japonica L.) and its main avian pollinator, the Japanese White-eye (Zosterops japonica), offer an excellent example of such an interaction as key members of the biotic community on Miyake-jima, which erupted in 2000 and continues to emit volcanic gases. Both species exhibit higher resistance to volcanic damage than other species. We examined the effects of volcanic activity on this plant-pollinator system by estimating pollen flow and the genetic diversity of the next generation. The results showed that despite a decrease in Camellia flowers, the partitioning of allelic richness among mother-tree pollen pools and seeds decreased while the migration rate of pollen from outside the study plot and the pollen donor diversity within a fruit increased as the index of volcanic damage increased. In areas with low food (flower) density due to volcanic damage, Z. japonica ranged over larger areas to satisfy its energy needs rather than moving to areas with higher food density. Consequently, the genetic diversity of the seeds (the next plant generation) increased with the index of volcanic damage. The results were consistent with previously published data on the movement of Z. japonica based on radio tracking and the genetic diversity of Camellia pollen adhering to pollinators. Overall, our results indicated that compensation mechanisms ensured better pollination after volcanic disturbance.

Genomic structural variation-mediated allelic suppression causes hybrid male sterility in rice.

PubMed

Shen, Rongxin; Wang, Lan; Liu, Xupeng; Wu, Jiang; Jin, Weiwei; Zhao, Xiucai; Xie, Xianrong; Zhu, Qinlong; Tang, Huiwu; Li, Qing; Chen, Letian; Liu, Yao-Guang

2017-11-03

Hybrids between divergent populations commonly show hybrid sterility; this reproductive barrier hinders hybrid breeding of the japonica and indica rice (Oryza sativa L.) subspecies. Here we show that structural changes and copy number variation at the Sc locus confer japonica-indica hybrid male sterility. The japonica allele, Sc-j, contains a pollen-essential gene encoding a DUF1618-domain protein; the indica allele, Sc-i, contains two or three tandem-duplicated ~ 28-kb segments, each carrying an Sc-j-homolog with a distinct promoter. In Sc-j/Sc-i hybrids, the high-expression of Sc-i in sporophytic cells causes suppression of Sc-j expression in pollen and selective abortion of Sc-j-pollen, leading to transmission ratio distortion. Knocking out one or two of the three Sc-i copies by CRISPR/Cas9 rescues Sc-j expression and male fertility. Our results reveal the gene dosage-dependent allelic suppression as a mechanism of hybrid incompatibility, and provide an effective approach to overcome the reproductive barrier for hybrid breeding.

Cedar pollen aggravates atopic dermatitis in childhood monozygotic twin patients with allergic rhino conjunctivitis.

PubMed

Murakami, Yukako; Matsui, Saki; Kijima, Akiko; Kitaba, Shun; Murota, Hiroyuki; Katayama, Ichiro

2011-09-01

We report a case of 7-year-old monozygotic twin patients with atopic dermatitis. The HLA haplotypes were HLA A2, A11, B27, B61, DR1, and DR4. Both serum IgE levels and cedar pollen radioallergosorbent test (RAST) scores were high in the twins (elder/younger sister: IgE: 5170/3980 IU/ml and Japansese cedar pollen: >100/64.0) in contrast to low mite and food RAST scores (Dermatophagoides Pterygonium; 0.59/0.4 and egg white 9.24/4.6). The patients showed positive immediate (20 min in both sisters) and delayed (24 hours in elder sister, 24, 48, 72 hours in younger sister) reactions to a scratch test with Japanese cedar pollen. Skin lesions on the face were aggravated and extended to the trunk and extremities during the Japanese cedar pollen season and gradually subsided in summer. Oral provocation with egg white or cow milk showed no exacerbations, and topical corticosteroid did not improve the eczema. In contrast, successful protection from severe scratching behaviors was achieved by use of topical anti-allergic eye drops and wearing nightgowns made by the mother.

Bee Pollen-Induced Anaphylaxis: A Case Report and Literature Review.

PubMed

Choi, Jeong Hee; Jang, Young Sook; Oh, Jae Won; Kim, Cheol Hong; Hyun, In Gyu

2015-09-01

Bee pollen is pollen granules packed by honey bees and is widely consumed as natural healthy supplements. Bee pollen-induced anaphylaxis has rarely been reported, and its allergenic components have never been studied. A 40-year-old male came to the emergency room with generalized urticaria, facial edema, dyspnea, nausea, vomiting, abdominal pain, and diarrhea 1 hour after ingesting one tablespoon of bee pollen. Oxygen saturation was 91%. His symptoms resolved after injection of epinephrine, chlorpheniramine, and dexamethasone. He had seasonal allergic rhinitis in autumn. Microscopic examination of the bee pollen revealed Japanese hop, chrysanthemum, ragweed, and dandelion pollens. Skin-prick with bee pollen extracts showed positive reactions at 0.1 mg/mL (A/H ratio > 3+). Serum specific IgE to ragweed was 25.2, chrysanthemum 20.6, and dandelion 11.4 kU/L; however, Japanese hop, honey-bee venom and yellow-jacket venom were negative (UniCAP®, Thermo Fisher Scientific, Uppsala, Sweden). Enzyme-linked immunosorbent assay (ELISA) confirmed serum specific IgE to bee-pollen extracts, and an ELISA inhibition assay for evaluation of cross-allergenicity of bee pollen and other weed pollens showed more than 90% of inhibition with chrysanthemum and dandelion and ~40% inhibition with ragweed at a concentration of 1 μg/mL. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and IgE-immunoblot analysis revealed 9 protein bands (11, 14, 17, 28, 34, 45, 52, 72, and 90 kDa) and strong IgE binding at 28-34 kDa, 45 and 52 kDa. In conclusion, healthcare providers should be aware of the potential risk of severe allergic reactions upon ingestion of bee pollen, especially in patients with pollen allergy.

Dynamics of sulfate and nitrate dry deposition associated with pollen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalili, E.K.

A field study of pollen dispersion and deposition from a remote forested area in Northern Wisconsin has been undertaken. Although the experiments constitute a case study in Wisconsin, the experimental site was chosen, which represents much of the Eastern US and Europe where acid rain is considered an important environmental problem. Measurements of dry deposition of pollen were made during the pollination season (May and June, 1987). Deposited particles were weighted to determine mass fluxes, then washed and subjected to ion chromatographic analysis for sulfate and nitrate. Ambient concentration of pollen were measured by a coarse particle sampler (Noll Inertialmore » Rotary Impact) during the same time period. The chemical analysis of pollen species collected around the sampling site as well as commercially available pollen demonstrated that sulfate and nitrate were present on all pollen samples. Many trace metals such as Fe, Al, Zn, Cu, Mn, Cd, Pb, Ca, and Si and organic acids were quantified. It was hypothesized that pollen accumulate extraneous amounts of non-essential, as well as essential elements from the soil supplying nutrient. Therefore, pollen can be used as a fingerprint for the availability and the level of contamination of a particular element in the forest soil environment. A model developed for measurement of coarse particle dry deposition was utilized to measure the pollen dry deposition velocity. It was shown that depositional velocity of pollen exceeds the settling velocity by a factor of 3 to 4, and both V{sub d} and fluxes of pollen grains increase with wind speed. Finally, the role of pollen dispersion and deposition has been discussed and emphasized for modeling of lake acidification in forested region.« less

RNA-Seq of Arabidopsis Pollen Uncovers Novel Transcription and Alternative Splicing1[C][W][OA

PubMed Central

Loraine, Ann E.; McCormick, Sheila; Estrada, April; Patel, Ketan; Qin, Peng

2013-01-01

Pollen grains of Arabidopsis (Arabidopsis thaliana) contain two haploid sperm cells enclosed in a haploid vegetative cell. Upon germination, the vegetative cell extrudes a pollen tube that carries the sperm to an ovule for fertilization. Knowing the identity, relative abundance, and splicing patterns of pollen transcripts will improve our understanding of pollen and allow investigation of tissue-specific splicing in plants. Most Arabidopsis pollen transcriptome studies have used the ATH1 microarray, which does not assay splice variants and lacks specific probe sets for many genes. To investigate the pollen transcriptome, we performed high-throughput sequencing (RNA-Seq) of Arabidopsis pollen and seedlings for comparison. Gene expression was more diverse in seedling, and genes involved in cell wall biogenesis were highly expressed in pollen. RNA-Seq detected at least 4,172 protein-coding genes expressed in pollen, including 289 assayed only by nonspecific probe sets. Additional exons and previously unannotated 5′ and 3′ untranslated regions for pollen-expressed genes were revealed. We detected regions in the genome not previously annotated as expressed; 14 were tested and 12 were confirmed by polymerase chain reaction. Gapped read alignments revealed 1,908 high-confidence new splicing events supported by 10 or more spliced read alignments. Alternative splicing patterns in pollen and seedling were highly correlated. For most alternatively spliced genes, the ratio of variants in pollen and seedling was similar, except for some encoding proteins involved in RNA splicing. This study highlights the robustness of splicing patterns in plants and the importance of ongoing annotation and visualization of RNA-Seq data using interactive tools such as Integrated Genome Browser. PMID:23590974

Relationships among indoor, outdoor, and personal airborne Japanese cedar pollen counts.

PubMed

Yamamoto, Naomichi; Matsuki, Yuuki; Yokoyama, Hiromichi; Matsuki, Hideaki

2015-01-01

Japanese cedar pollinosis (JCP) is an important illness caused by the inhalation of airborne allergenic cedar pollens, which are dispersed in the early spring throughout the Japanese islands. However, associations between pollen exposures and the prevalence or severity of allergic symptoms are largely unknown, due to a lack of understanding regarding personal pollen exposures in relation to indoor and outdoor concentrations. This study aims to examine the relationships among indoor, outdoor, and personal airborne Japanese cedar pollen counts. We conducted a 4-year monitoring campaign to quantify indoor, outdoor, and personal airborne cedar pollen counts, where the personal passive settling sampler that has been previously validated against a volumetric sampler was used to count airborne pollen grains. A total of 256 sets of indoor, outdoor, and personal samples (768 samples) were collected from 9 subjects. Medians of the seasonally-integrated indoor-to-outdoor, personal-to-outdoor, and personal-to-indoor ratios of airborne pollen counts measured for 9 subjects were 0.08, 0.10, and 1.19, respectively. A greater correlation was observed between the personal and indoor counts (r = 0.89) than between the personal and outdoor counts (r = 0.71), suggesting a potential inaccuracy in the use of outdoor counts as a basis for estimating personal exposures. The personal pollen counts differed substantially among the human subjects (49% geometric coefficient of variation), in part due to the variability in the indoor counts that have been found as major determinants of the personal pollen counts. The findings of this study highlight the need for pollen monitoring in proximity to human subjects to better understand the relationships between pollen exposures and the prevalence or severity of pollen allergy.

Relationships among Indoor, Outdoor, and Personal Airborne Japanese Cedar Pollen Counts

PubMed Central

Yamamoto, Naomichi; Matsuki, Yuuki; Yokoyama, Hiromichi; Matsuki, Hideaki

2015-01-01

Japanese cedar pollinosis (JCP) is an important illness caused by the inhalation of airborne allergenic cedar pollens, which are dispersed in the early spring throughout the Japanese islands. However, associations between pollen exposures and the prevalence or severity of allergic symptoms are largely unknown, due to a lack of understanding regarding personal pollen exposures in relation to indoor and outdoor concentrations. This study aims to examine the relationships among indoor, outdoor, and personal airborne Japanese cedar pollen counts. We conducted a 4-year monitoring campaign to quantify indoor, outdoor, and personal airborne cedar pollen counts, where the personal passive settling sampler that has been previously validated against a volumetric sampler was used to count airborne pollen grains. A total of 256 sets of indoor, outdoor, and personal samples (768 samples) were collected from 9 subjects. Medians of the seasonally-integrated indoor-to-outdoor, personal-to-outdoor, and personal-to-indoor ratios of airborne pollen counts measured for 9 subjects were 0.08, 0.10, and 1.19, respectively. A greater correlation was observed between the personal and indoor counts (r = 0.89) than between the personal and outdoor counts (r = 0.71), suggesting a potential inaccuracy in the use of outdoor counts as a basis for estimating personal exposures. The personal pollen counts differed substantially among the human subjects (49% geometric coefficient of variation), in part due to the variability in the indoor counts that have been found as major determinants of the personal pollen counts. The findings of this study highlight the need for pollen monitoring in proximity to human subjects to better understand the relationships between pollen exposures and the prevalence or severity of pollen allergy. PMID:26110813

Clinico-immunochemical studies on airborne Areca catechu L. Pollen, a probable risk factor in emergency asthma hospitalization from Eastern India.

PubMed

Chakraborty, Pampa; Mandal, Jyotshna; Sarkar, Eva; Chowdhury, Indrani; Gupta-Bhattacharya, Swati

2009-01-01

The pollen grain of the Areca catechu L. tree is airborne and allergenic. This study aimed to know the role of this pollen as a source of aeroallergen with effect on emergency asthma hospitalization, to isolate its important allergic fraction and to check its cross-reaction with betel nut. Areca pollen was monitored with a Burkard sampler. Determination of allergenic activities was studied by in vivo and in vitro analyses. Asthma hospitalization data were collected from two nearby hospitals. The pollen extract was fractionated by a combination of DEAE-Sephadex and Sephacryl S-200 column. The protein components were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cross-reactivity of Areca pollen and betel nut was shown by IgE enzyme-linked immunosorbent assay (ELISA) inhibition. The Areca pollen was perennially airborne. Skin test results of respiratory allergic patients showed 38.6% positivity. The detected aeroallergen spots in particle immunoblotting correlated significantly with airborne pollen count. Areca pollen showed a significant positive correlation with asthma hospitalization. There are 6 IgE-reactive protein components in the whole-pollen extract. IgE-reactive fraction 1 was resolved into 4 subfractions. Subfraction 1a showing IgE reactivity contained 3 protein components, among which 2 of 48 and 118 kDa were IgE reactive. The 48-kDa component was reported to be cross-reactive with other palm pollen types. In IgE ELISA inhibition, the betel nut extract showed 50% inhibition with about 110 ng/ml concentration. A. catechu pollen is a significant contributor to the aeroallergen load in India. Its partially purified IgE-reactive fraction may be useful in therapeutics. The betel nut extract showed remarkable cross-reactivity with Areca pollen. Copyright (C) 2009 S. Karger AG, Basel.

The effects of foraging role and genotype on light and sucrose responsiveness in honey bees (Apis mellifera L.).

PubMed

Tsuruda, Jennifer M; Page, Robert E

2009-12-14

In honey bees, the sensory system can be measured by touching sugar water to the antennae, eliciting the extension of the proboscis. The proboscis extension response (PER) [6,13] is closely associated with complex behavioral traits involving foraging and learning [30-32,34-36,43-49]. Bees specializing in pollen foraging are more responsive to low concentrations of sucrose solution and, as a consequence, perform better in associative learning assays [4,43,46-48]. An important unanswered question is whether sensory-motor differences between pollen and nectar specialists are restricted to the gustatory modality or whether pollen foragers are in general more sensitive to sensory stimuli associated with foraging. We used an assay designed to test responsiveness to varying intensities of light [11] and tested responsiveness to varying concentrations of sucrose in wild-type pollen and non-pollen foragers and bees artificially-selected for differences in pollen-hoarding behavior [27]. Workers of the high pollen-hoarding strain are more likely to specialize on collecting pollen. In wild-type bees, pollen foragers were more responsive to sucrose and light than non-pollen foragers. In the selected strains, high pollen-hoarding pre-foragers were more responsive to sucrose and light than low pollen-hoarding pre-foragers. These PER and light assays demonstrate a positive relationship between the gustatory and visual sensory modalities with respect to foraging behavior and genotype. We propose that light responsiveness, in addition to sucrose responsiveness, is a component of a pollen-hoarding behavioral syndrome - a suite of traits that covary with hoarding behavior [51,52] - previously described for honey bees [14,37,41]. We suggest that the modulation of the sensory system may be partially constrained by the interdependent modulation of multiple sensory modalities associated with hoarding and foraging.

Rate of dehydration of corn (Zea mays L.) pollen in the air.

PubMed

Aylor, Donald E

2003-10-01

The water content of corn (Zea mays L.) pollen directly affects its dispersal in the atmosphere through its effect on settling speed and viability. Therefore, the rate of water loss from pollen after being shed from the anther is an important component of a model to predict effective pollen transport distances in the atmosphere. The rate of water loss from corn pollen in air was determined using two methods: (1) by direct weighing of samples containing approximately 5 x 10(4) grains, and (2) by microscopic measurement of the change in size of individual grains. The conductance of the pollen wall to water loss was derived from the time rate of change of pollen mass or pollen grain size. The two methods gave average conductance values of 0.026 and 0.027 cm s-1, respectively. In other experiments, the water potential, psi, of corn pollen was determined at various values of relative water content (dry weight basis), either by using a thermocouple psychrometer or by allowing samples of pollen to come to vapour equilibrium with various saturated salt solutions. Non-linear regression analysis of the data yielded psi (MPa) = -3.218 theta(-1.35) (r2 = 0.94; for -298 < or = psi < or = -1 MPa). This result was incorporated into a model differential equation for the rate of water loss from pollen. The model agreed well (r2 approximately 0.98) with the observed time-course of the decrease of water content of pollen grains exposed to a range of temperature and humidity conditions.

Development and validation of a 5-day-ahead hay fever forecast for patients with grass-pollen-induced allergic rhinitis

NASA Astrophysics Data System (ADS)

de Weger, Letty A.; Beerthuizen, Thijs; Hiemstra, Pieter S.; Sont, Jacob K.

2014-08-01

One-third of the Dutch population suffers from allergic rhinitis, including hay fever. In this study, a 5-day-ahead hay fever forecast was developed and validated for grass pollen allergic patients in the Netherlands. Using multiple regression analysis, a two-step pollen and hay fever symptom prediction model was developed using actual and forecasted weather parameters, grass pollen data and patient symptom diaries. Therefore, 80 patients with a grass pollen allergy rated the severity of their hay fever symptoms during the grass pollen season in 2007 and 2008. First, a grass pollen forecast model was developed using the following predictors: (1) daily means of grass pollen counts of the previous 10 years; (2) grass pollen counts of the previous 2-week period of the current year; and (3) maximum, minimum and mean temperature ( R 2 = 0.76). The second modeling step concerned the forecasting of hay fever symptom severity and included the following predictors: (1) forecasted grass pollen counts; (2) day number of the year; (3) moving average of the grass pollen counts of the previous 2 week-periods; and (4) maximum and mean temperatures ( R 2 = 0.81). Since the daily hay fever forecast is reported in three categories (low-, medium- and high symptom risk), we assessed the agreement between the observed and the 1- to 5-day-ahead predicted risk categories by kappa, which ranged from 65 % to 77 %. These results indicate that a model based on forecasted temperature and grass pollen counts performs well in predicting symptoms of hay fever up to 5 days ahead.

Development and validation of a 5-day-ahead hay fever forecast for patients with grass-pollen-induced allergic rhinitis.

PubMed

de Weger, Letty A; Beerthuizen, Thijs; Hiemstra, Pieter S; Sont, Jacob K

2014-08-01

One-third of the Dutch population suffers from allergic rhinitis, including hay fever. In this study, a 5-day-ahead hay fever forecast was developed and validated for grass pollen allergic patients in the Netherlands. Using multiple regression analysis, a two-step pollen and hay fever symptom prediction model was developed using actual and forecasted weather parameters, grass pollen data and patient symptom diaries. Therefore, 80 patients with a grass pollen allergy rated the severity of their hay fever symptoms during the grass pollen season in 2007 and 2008. First, a grass pollen forecast model was developed using the following predictors: (1) daily means of grass pollen counts of the previous 10 years; (2) grass pollen counts of the previous 2-week period of the current year; and (3) maximum, minimum and mean temperature (R (2)=0.76). The second modeling step concerned the forecasting of hay fever symptom severity and included the following predictors: (1) forecasted grass pollen counts; (2) day number of the year; (3) moving average of the grass pollen counts of the previous 2 week-periods; and (4) maximum and mean temperatures (R (2)=0.81). Since the daily hay fever forecast is reported in three categories (low-, medium- and high symptom risk), we assessed the agreement between the observed and the 1- to 5-day-ahead predicted risk categories by kappa, which ranged from 65 % to 77 %. These results indicate that a model based on forecasted temperature and grass pollen counts performs well in predicting symptoms of hay fever up to 5 days ahead.

Pollen record of the penultimate glacial period in Yuchi Basin, Central Taiwan

NASA Astrophysics Data System (ADS)

Lai, Hsiao-Yin; Liew, Ping-Mei

2010-05-01

Pollen records of the penultimate glacial period are scare not only in Taiwan, but also in East Asia area. Hence, this study intends to provide a new pollen record from a site, Yuchi Basin, in central Taiwan, which may improve our knowledge of the penultimate glacial period. The sediment core, CTN6, was drilled in the northern part of Yuchi Basin. The core is 29.4 m in length and the sampling interval is 10 cm. In total, 86 samples are processed for pollen analysis. Three pollen zones (I,II and III) are determined according to the ratio of arboreal pollens (AP) and non-arboreal pollens (NAP). Because of the scarcity of dating data, pollen assemblages compared with previous pollen records at peripheral areas is utilized to estimate the ages of each pollen zone. AP dominate (60%) Zone I and III, which consist mainly of Cyclobalanopsis-Castanopsis. Thus, Zone I may mark the MIS 5 because of a Cyclobalanopsis-Castanopsis dominant condition. In Zone II, the increase in NAP and pollen of Taxodiaceae and decrease in pollens of Cyclobalanopsis-Castanopsis indicates the penultimate glacial period, i.e. MIS 6. In contrast to the evergreen broadleaved forest found there today, the herbs occupied the basin in Zone II, indicating a relatively dry climate condition than present. Furthermore, during the penultimate glacial period, the climate condition of early part is wetter, evidenced by a higher AP/NAP in Zone IIb. Finally, comparing with the last glacial period in Toushe, we suggest that the penultimate glacial period is drier due to the lower AP/NAP.

Evaluation of the Nutritional and Storage Quality of Meatballs Formulated with Bee Pollen.

PubMed

Turhan, Sadettin; Yazici, Fehmi; Saricaoglu, Furkan Turker; Mortas, Mustafa; Genccelep, Huseyin

2014-01-01

In this study, the nutritional and storage quality of meatballs formulated with different levels (0, 1.5, 3.0, 4.5 and 6.0%) of bee pollen were investigated during storage at 41℃ for 9 d. Protein content of meatballs increased, while moisture content decreased with increased pollen. The addition of pollen improved cooking loss but decreased the redness (Hunter a value) and sensory scores. Textural parameters (hardness, springsness, gumminess, and chewiness) were affected by pollen addition and the hardness and gumminess values of meatballs decreased as the pollen content increased. While C18:0 content of meatballs slightly decreased with pollen addition, C18:2n-6c, C18:3n-3, C20:5n-3, and PUFA contents increased. The PUFA/saturated fatty acids (P/S) ratio increased from 0.05 in the control to 0.09 in meatballs with 6.0% pollen. The n-6/n-3 ratio decreased from 11.84 in the control to 3.65 in the meatballs with 6.0% pollen. The addition of pollen retarded the lipid oxidation and inhibited the bacterial growth in meatballs. The pH, redness, TBA value and total aerobic mesophilic bacteria, coliform bacteria and S. aureus counts values changed significantly during storage. The results suggest that bee pollen could be added to enhance the nutritional and storage quality of meatballs with minimal changes in composition and/or sensory properties.

Evaluation of the Nutritional and Storage Quality of Meatballs Formulated with Bee Pollen

PubMed Central

2014-01-01

In this study, the nutritional and storage quality of meatballs formulated with different levels (0, 1.5, 3.0, 4.5 and 6.0%) of bee pollen were investigated during storage at 41℃ for 9 d. Protein content of meatballs increased, while moisture content decreased with increased pollen. The addition of pollen improved cooking loss but decreased the redness (Hunter a value) and sensory scores. Textural parameters (hardness, springsness, gumminess, and chewiness) were affected by pollen addition and the hardness and gumminess values of meatballs decreased as the pollen content increased. While C18:0 content of meatballs slightly decreased with pollen addition, C18:2n-6c, C18:3n-3, C20:5n-3, and PUFA contents increased. The PUFA/saturated fatty acids (P/S) ratio increased from 0.05 in the control to 0.09 in meatballs with 6.0% pollen. The n-6/n-3 ratio decreased from 11.84 in the control to 3.65 in the meatballs with 6.0% pollen. The addition of pollen retarded the lipid oxidation and inhibited the bacterial growth in meatballs. The pH, redness, TBA value and total aerobic mesophilic bacteria, coliform bacteria and S. aureus counts values changed significantly during storage. The results suggest that bee pollen could be added to enhance the nutritional and storage quality of meatballs with minimal changes in composition and/or sensory properties. PMID:26761280

Spatiotemporal Variation in the Environmental Controls of C4-Grass Origin and Ecology: Insights from Grass-Pollen δ13C Data

NASA Astrophysics Data System (ADS)

Nelson, D. M.; Urban, M.; Hu, F.

2014-12-01

Understanding the environmental factors controlling the origin and shifting abundance of C4 grasses in Earth's history is useful for projecting the response of C4-grass dominated grasslands to future environmental change. Unfortunately, grass pollen is typically morphologically indistinct, making palynological analysis a blunt tool for studying C4-grasses in the paleorecord. δ13C of individual grass-pollen grains using a spooling wire microcombustion device interfaced with an isotope ratio mass spectrometer (Single Pollen Isotope Ratio AnaLysis, SPIRAL) overcomes this challenge and the potential biases of δ13C data from other substrates (e.g. leaf waxes). To assess the presence and relative abundance of C3- and C4-grass pollen in samples of unknown composition, we developed a hierarchical Bayesian model, trained with ~1,900 δ13C values from pollen grains of 31 grass species. Surface-sediment data from Africa, Australia, and North America demonstrate the reliability of this technique for quantifying C4-grass abundance on the landscape. To investigate the timing and control of the origin of C4-grasses we analyzed samples from the Oligocene-Miocene from Europe and from the Eocene from North America. Results indicate that C4 grasses appeared on the landscape of southwest Europe no later than the early Oligocene, implying that low atmospheric pCO2 may not have been the main driver and/or precondition for the development of C4 photosynthesis in the grass family. In contrast, we found no evidence for C4 grasses in the southeast United States before pCO2 fell. In application of SPIRAL to the late Quaternary, we found that shifts in pCO2 and moisture balance exerted key controls on the relative abundance of C3 and C4 grasses in Africa and Australia. Overall, our results imply that as in the past, future changes in the C3/C4 composition of grass-dominated ecosystems will likely exhibit striking spatiotemporal variability as a result of differing combinations of environmental controls.

Differences in Reporting the Ragweed Pollen Season Using Google Trends across 15 Countries.

PubMed

Bousquet, Jean; Agache, Ioana; Berger, Uwe; Bergmann, Karl-Christian; Besancenot, Jean-Pierre; Bousquet, Philippe J; Casale, Tom; d'Amato, Gennaro; Kaidashev, Igor; Khaitov, Musa; Mösges, Ralph; Nekam, Kristof; Onorato, Gabrielle L; Plavec, Davor; Sheikh, Aziz; Thibaudon, Michel; Vautard, Robert; Zidarn, Mihaela

2018-05-09

Google Trends (GT) searches trends of specific queries in Google, which potentially reflect the real-life epidemiology of allergic rhinitis. We compared GT terms related to ragweed pollen allergy in American and European Union countries with a known ragweed pollen season. Our aim was to assess seasonality and the terms needed to perform the GT searches and to compare these during the spring and summer pollen seasons. We examined GT queries from January 1, 2011, to January 4, 2017. We included 15 countries with a known ragweed pollen season and used the standard 5-year GT graphs. We used the GT translation for all countries and the untranslated native terms for each country. The results of "pollen," "ragweed," and "allergy" searches differed between countries, but "ragweed" was clearly identified in 12 of the 15 countries. There was considerable heterogeneity of findings when the GT translation was used. For Croatia, Hungary, Romania, Serbia, and Slovenia, the GT translation was inappropriate. The country patterns of "pollen," "hay fever," and "allergy" differed in 8 of the 11 countries with identified "ragweed" queries during the spring and the summer, indicating that the perception of tree and grass pollen allergy differs from that of ragweed pollen. To investigate ragweed pollen allergy using GT, the term "ragweed" as a plant is required and the translation of "ragweed" in the native language needed. © 2018 S. Karger AG, Basel.

Loss of the Arabidopsis thaliana P4-ATPases ALA6 and ALA7 impairs pollen fitness and alters the pollen tube plasma membrane.

PubMed

McDowell, Stephen C; López-Marqués, Rosa L; Cohen, Taylor; Brown, Elizabeth; Rosenberg, Alexa; Palmgren, Michael G; Harper, Jeffrey F

2015-01-01

Members of the P4 subfamily of P-type ATPases are thought to create and maintain lipid asymmetry in biological membranes by flipping specific lipids between membrane leaflets. In Arabidopsis, 7 of the 12 Aminophospholipid ATPase (ALA) family members are expressed in pollen. Here we show that double knockout of ALA6 and ALA7 (ala6/7) results in siliques with a ~2-fold reduction in seed set with a high frequency of empty seed positions near the bottom. Seed set was reduced to near zero when plants were grown under a hot/cold temperature stress. Reciprocal crosses indicate that the ala6/7 reproductive deficiencies are due to a defect related to pollen transmission. In-vitro growth assays provide evidence that ala6/7 pollen tubes are short and slow, with ~2-fold reductions in both maximal growth rate and overall length relative to wild-type. Outcrosses show that when ala6/7 pollen are in competition with wild-type pollen, they have a near 0% success rate in fertilizing ovules near the bottom of the pistil, consistent with ala6/7 pollen having short and slow growth defects. The ala6/7 phenotypes were rescued by the expression of either an ALA6-YFP or GFP-ALA6 fusion protein, which showed localization to both the plasma membrane and highly-mobile endomembrane structures. A mass spectrometry analysis of mature pollen grains revealed significant differences between ala6/7 and wild-type, both in the relative abundance of lipid classes and in the average number of double bonds present in acyl side chains. A change in the properties of the ala6/7 plasma membrane was also indicated by a ~10-fold reduction of labeling by lipophilic FM-dyes relative to wild-type. Together, these results indicate that ALA6 and ALA7 provide redundant activities that function to directly or indirectly change the distribution and abundance of lipids in pollen, and support a model in which ALA6 and ALA7 are critical for pollen fitness under normal and temperature-stress conditions.

Loss of the Arabidopsis thaliana P4-ATPases ALA6 and ALA7 impairs pollen fitness and alters the pollen tube plasma membrane

PubMed Central

McDowell, Stephen C.; López-Marqués, Rosa L.; Cohen, Taylor; Brown, Elizabeth; Rosenberg, Alexa; Palmgren, Michael G.; Harper, Jeffrey F.

2015-01-01

Members of the P4 subfamily of P-type ATPases are thought to create and maintain lipid asymmetry in biological membranes by flipping specific lipids between membrane leaflets. In Arabidopsis, 7 of the 12 Aminophospholipid ATPase (ALA) family members are expressed in pollen. Here we show that double knockout of ALA6 and ALA7 (ala6/7) results in siliques with a ~2-fold reduction in seed set with a high frequency of empty seed positions near the bottom. Seed set was reduced to near zero when plants were grown under a hot/cold temperature stress. Reciprocal crosses indicate that the ala6/7 reproductive deficiencies are due to a defect related to pollen transmission. In-vitro growth assays provide evidence that ala6/7 pollen tubes are short and slow, with ~2-fold reductions in both maximal growth rate and overall length relative to wild-type. Outcrosses show that when ala6/7 pollen are in competition with wild-type pollen, they have a near 0% success rate in fertilizing ovules near the bottom of the pistil, consistent with ala6/7 pollen having short and slow growth defects. The ala6/7 phenotypes were rescued by the expression of either an ALA6-YFP or GFP-ALA6 fusion protein, which showed localization to both the plasma membrane and highly-mobile endomembrane structures. A mass spectrometry analysis of mature pollen grains revealed significant differences between ala6/7 and wild-type, both in the relative abundance of lipid classes and in the average number of double bonds present in acyl side chains. A change in the properties of the ala6/7 plasma membrane was also indicated by a ~10-fold reduction of labeling by lipophilic FM-dyes relative to wild-type. Together, these results indicate that ALA6 and ALA7 provide redundant activities that function to directly or indirectly change the distribution and abundance of lipids in pollen, and support a model in which ALA6 and ALA7 are critical for pollen fitness under normal and temperature-stress conditions. PMID:25954280

Comprehensive analysis of tobacco pollen transcriptome unveils common pathways in polar cell expansion and underlying heterochronic shift during spermatogenesis

PubMed Central

2012-01-01

Background Many flowering plants produce bicellular pollen. The two cells of the pollen grain are destined for separate fates in the male gametophyte, which provides a unique opportunity to study genetic interactions that govern guided single-cell polar expansion of the growing pollen tube and the coordinated control of germ cell division and sperm cell fate specification. We applied the Agilent 44 K tobacco gene chip to conduct the first transcriptomic analysis of the tobacco male gametophyte. In addition, we performed a comparative study of the Arabidopsis root-hair trichoblast transcriptome to evaluate genetic factors and common pathways involved in polarized cell-tip expansion. Results Progression of pollen grains from freshly dehisced anthers to pollen tubes 4 h after germination is accompanied with > 5,161 (14.9%) gametophyte-specific expressed probes active in at least one of the developmental stages. In contrast, > 18,821 (54.4%) probes were preferentially expressed in the sporophyte. Our comparative approach identified a subset of 104 pollen tube-expressed genes that overlap with root-hair trichoblasts. Reverse genetic analysis of selected candidates demonstrated that Cu/Zn superoxide dismutase 1 (CSD1), a WD-40 containing protein (BP130384), and Replication factor C1 (NtRFC1) are among the central regulators of pollen-tube tip growth. Extension of our analysis beyond the second haploid mitosis enabled identification of an opposing-dynamic accumulation of core regulators of cell proliferation and cell fate determinants in accordance with the progression of the germ cell cycle. Conclusions The current study provides a foundation to isolate conserved regulators of cell tip expansion and those that are unique for pollen tube growth to the female gametophyte. A transcriptomic data set is presented as a benchmark for future functional studies using developing pollen as a model. Our results demonstrated previously unknown functions of certain genes in pollen-tube tip growth. In addition, we highlighted the molecular dynamics of core cell-cycle regulators in the male gametophyte and postulated the first genetic model to account for the differential timing of spermatogenesis among angiosperms and its coordination with female gametogenesis. PMID:22340370

The effect of substrate, ADP and uncoupler on the respiration of tomato pollen during incubation in vitro at moderately high temperature.

PubMed

Karapanos, I C; Akoumianakis, K A; Olympios, C M; Passam, H C

2009-09-01

Pollen of tomato cv. Supermarmande was collected from greenhouse-grown plants at various intervals throughout the year and arbitrarily classified as of high, medium or low respiratory activity on the basis of CO(2) production during 8 h incubation in vitro at 30 degrees C, a temperature that is considered to be moderately high for tomato fruit set. After an initial burst of respiration during the first stage of hydration at 30 degrees C (>1 h), the respiration rate of pollen of all three categories declined, the decrease being greater in the lots with a low or medium respiratory activity than in the high category. During hydration (10 min after the start of incubation), the addition of succinate or reduced beta-nicotinamide adenine dinucleotide (NADH) to the substrate increased the respiratory rate of slowly-respiring pollen more than that of fast-respiring pollen, but carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and adenosine 5'-diphosphate (ADP) had less effect. After 1-4 h incubation, the respiration rate of the slow- or medium-respiring pollen lots had decreased, but was stimulated by succinate or NADH, and to a lesser degree by ADP. By 7 h, the respiration rate of all pollen lots had declined and was stimulated less by substrate, ADP or CCCP. The oxidation of NADH by tomato pollen contrasts with the failure of other pollen species to utilize this substrate; moreover, a synergistic effect of NADH and succinate was consistently observed. We conclude that the decline in respiration during incubation for up to 4 h at 30 degrees C may reflect a lack of respiratory substrate. After 7 h, however, the decreased response to substrate indicates a loss of mitochondrial integrity or an accumulation of metabolic inhibitors. It is concluded that at 30 degrees C (a moderately high temperature for tomato pollen), the initially high rate of respiration leads to exhaustion of the endogenous respiratory substrates (particularly in pollen with low to medium respiratory activity), but subsequently to ageing and a loss of mitochondrial activity.

Preservation of cycad and Ginkgo pollen

USGS Publications Warehouse

Frederiksen, N.O.

1978-01-01

Pollen grains of Ginkgo, Cycas, and Encephalartos were chemically treated together with pollen of Quercus, Alnus, and Pinus, the latter three genera being used as standards. The experiments showed that: (1) boiling the pollen for 8-10 hours in 10% KOH had little if any effect on any of the grains; (2) lengthy acetolysis treatment produced some degradation or corrosion, particularly in Ginkgo and Cycas, but the grains of even these genera remained easily recognizable; (3) oxidation with KMnO4 followed by H2O2 showed that pollen of Ginkgo, Cycas, and Encephalartos remains better preserved than that of Quercus and Alnus, and although Ginkgo and Encephalartos probably are slightly less resistant to oxidation than Pinus, no great differences exists between these monosulcate types and Pinus. Thus the experiments show that, at least for sediments low in bacteria, cycad and Ginkgo pollen should be well represented in the fossil record as far as their preservational capabilities are concerned. ?? 1978.

Effects of climate change and seed dispersal on airborne ragweed pollen loads in Europe

NASA Astrophysics Data System (ADS)

Hamaoui-Laguel, Lynda; Vautard, Robert; Liu, Li; Solmon, Fabien; Viovy, Nicolas; Khvorostyanov, Dmitry; Essl, Franz; Chuine, Isabelle; Colette, Augustin; Semenov, Mikhail A.; Schaffhauser, Alice; Storkey, Jonathan; Thibaudon, Michel; Epstein, Michelle M.

2015-08-01

Common ragweed (Ambrosia artemisiifolia) is an invasive alien species in Europe producing pollen that causes severe allergic disease in susceptible individuals. Ragweed plants could further invade European land with climate and land-use changes. However, airborne pollen evolution depends not only on plant invasion, but also on pollen production, release and atmospheric dispersion changes. To predict the effect of climate and land-use changes on airborne pollen concentrations, we used two comprehensive modelling frameworks accounting for all these factors under high-end and moderate climate and land-use change scenarios. We estimate that by 2050 airborne ragweed pollen concentrations will be about 4 times higher than they are now, with a range of uncertainty from 2 to 12 largely depending on the seed dispersal rate assumptions. About a third of the airborne pollen increase is due to on-going seed dispersal, irrespective of climate change. The remaining two-thirds are related to climate and land-use changes that will extend ragweed habitat suitability in northern and eastern Europe and increase pollen production in established ragweed areas owing to increasing CO2. Therefore, climate change and ragweed seed dispersal in current and future suitable areas will increase airborne pollen concentrations, which may consequently heighten the incidence and prevalence of ragweed allergy.

Pollen, vegetation, and climate relationships along the Dalton Highway, Alaska, USA: a basis for holocene paleoecological and paleoclimatic studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Short, S.K.; Andrews, J.T.; Webber, P.J.

The Dalton Highway extends from Fairbanks, in the interior of Alaska, to Prudhoe Bay on the Arctic Coastal Plain. Over this 600-km transect, July temperatures vary from 17 to 5/sup 0/C. Studies of vegetation along the Dalton Highway identified nine major zones. During the vegetation survey moss polsters were collected within the survey quadrats. Two hundred and nineteen individual moss polsters document regional variations in the modern pollen spectra along this vegetation/climate transect. Treeline is distinguished by a change from dominance by spruce and shrub (especially alder) pollen to the south to herb and shrub (especially willow) pollen dominance tomore » the north; a shift from high modern pollen concentration values to very low values is also noted. Discriminant analysis indicated that the vegetation zones are also defined by different pollen assemblages, suggesting that former changes in vegetation during the Holocene, as recorded in peat deposits, could be interpreted from pollen diagrams. Transfer functions were developed to examine the statistical association between the modern pollen rain and several climatic parameters. The correlation between pollen taxa and mean July temperature was r = 0.84. The most important taxa in the equation are Picea, Alnus, Pinus, Sphagnum, and Betula. 59 references, 7 figures, 4 tables.« less

Defining thresholds of specific IgE levels to grass pollen and birch pollen allergens improves clinical interpretation.

PubMed

Van Hoeyveld, Erna; Nickmans, Silvie; Ceuppens, Jan L; Bossuyt, Xavier

2015-10-23

Cut-off values and predictive values are used for the clinical interpretation of specific IgE antibody results. However, cut-off levels are not well defined, and predictive values are dependent on the prevalence of disease. The objective of this study was to document clinically relevant diagnostic accuracy of specific IgE for inhalant allergens (grass pollen and birch pollen) based on test result interval-specific likelihood ratios. Likelihood ratios are independent of the prevalence and allow to provide diagnostic accuracy information for test result intervals. In a prospective study we included consecutive adult patients presenting at an allergy clinic with complaints of rhinitis or rhinoconjunctivitis. The standard for diagnosis was a suggestive clinical history of grass or birch pollen allergy and a positive skin test. Specific IgE was determined with the ImmunoCAP Fluorescence Enzyme Immuno-Assay. We established specific IgE test result interval related likelihood ratios for clinical allergy to inhalant allergens (grass pollen, rPhl p 1,5, birch pollen, rBet v 1). The likelihood ratios for allergy increased with increasing specific IgE antibody levels. The likelihood ratio was <0.03 for specific IgE <0.1 kU/L, between 0.1 and 1.4 for specific IgE between 0.1 kU/L and 0.35 kU/L, between 1.4 and 4.2 for specific IgE between 0.35 kU/L and 3.5 kU/L, >6.3 for specific IgE>0.7, and very high (∞) for specific IgE >3.5 kU/L. Test result interval specific likelihood ratios provide a useful tool for the interpretation of specific IgE test results for inhalant allergens. Copyright © 2015 Elsevier B.V. All rights reserved.

Mating system and pollen dispersal in Eugenia dysenterica (Myrtaceae) germplasm collection: tools for conservation and domestication.

PubMed

Rodrigues, Eduardo B; Collevatti, Rosane G; Chaves, Lázaro J; Moreira, Lucas R; Telles, Mariana P C

2016-04-01

Eugenia dysenterica DC. (Myrtaceae) is a perennial tree producing edible fruits and ornamental flowers of potential value widely distributed in Brazilian "Cerrados" (savannas), but available genetic resources and potential for future breeding programs must be evaluated. Here we evaluated the reproductive system and pollen-mediated gene flow in one generation of Eugenia dysenterica germplasm collection of Agronomy School, Federal University of Goiás (in Goiânia city, Central Brazil). We collected leaves from all adults from the germplasm collection (682 plants) and seeds (542) from 23 mother-trees. Genotypes were obtained for seven microsatellite loci. Genetic diversity was high and did not significantly differ between adults (H e = 0.777) and progeny arrays (H e = 0.617). Our results showed that E. dysenterica has an allogamous mating system in the germplasm collection (t m = 0.957), but with high and significant biparental inbreeding (t m - t s = 0.109). Because sibs are very close to each other, mating between closely related individuals is likely. Paternity correlation was also relatively high, indicating a 11.9 % probability that a randomly chosen pair of outcrossed progeny from the same array are full sibs. The maximum pollen dispersal distance (224 m), estimated using assignment test, corresponded to the boundaries of the orchard. We were able to assign the paternity to only 64 % of the 349 seeds analyzed, indicating potential pollen immigration to the germplasm collection. The variance effective population size estimated for one maternal family in the germplasm collection (N ev = 3.42) is very close to the theoretical maximum value for half-sibs (Nev = 4.0). Because E. dysenterica has a long life cycle and generation time, the maintenance of an effective population size of at least 100 in the germplasm collection is suggested, which can be achieved by maintaining a seed-trees number around 30 individuals.

Induction of IgE-mediated immediate hypersensitivity to Group I rye grass pollen allergen and allergoids in non-allergic man

PubMed Central

Marsh, D. G.; Lichtenstein, L. M.; Norman, P. S.

1972-01-01

The major (Group I) allergen of rye grass pollen and two of its allergoids, adsorbed on alumina gel, were injected into three groups of non-allergic humans. In addition to inducing the anticipated blocking antibody (IgG) response, all individuals developed immediate skin hypersensitivity to the allergen and its allergoids characteristic of reaginic antibody-(IgE-)mediated reactions. At some time during the course of the study, virtually every individual's peripheral blood leucocytes were also found to release histamine when challenged in vitro with low concentrations of allergen and allergoids. Quantitatively, each person's skin and leucocyte sensitivities were not as well correlated as in naturally allergic people. Leucocyte responsiveness was generally shortlived, but could be restored by antigenic restimulation. Allergoid: allergen sensitivity ratios were greater in allergen-than allergoid-immunized individuals, but less than in naturally allergic individuals. Unexpectedly, allergoid-immunized individuals' leucocytes were more sensitive to allergen than allergoid. Despite the observed skin and leucocyte reactivities, none of the people showed clinical manifestations of hay fever following natural exposure to pollen. The skin sensitivity of the artificially sensitized individuals could be passively transferred to non-allergic humans by intradermal injection of serum (P-K Test), thereby implicating the involvement of IgE antibody. Further proof of the role of IgE was obtained by blocking the P-K test, either by heating the serum or by adsorbing it using an anti-IgE immunosorbent. PMID:4113385

Pollen Characterization in Size Segregated Atmospheric Aerosol

NASA Astrophysics Data System (ADS)

Kolpakova, Anna; Hovorka, Jan; Klán, Miroslav

2017-12-01

The first stage of a High Volumetric Cascade Impactor - HiVol (BGI-900), used for sampling of aerosol particles larger than 10 micrometres in aerodynamic diameter, was tested for bioaerosol sampling. Low air flow-rate and low pressure-drop at the jets of the first stage and high air volume are advantageous parameters, which would favour the use of the first stage for bioaerosol sampling. The sampling went in urban, rural and background localities, Prague, Brezno and Laz respectively in the Czech Republic, in summer and autumn. Pollen was separated from the impaction substrate, polyurethane foam, into homogeneous deposit on Nylon filter. The homogeneity of the deposit varied within 4%. Representative portion of the deposit was analysed by a scanning electron microscopy - SEM. There were taken 485 SEM images from 12 samples in 3 localities. Pollen grains were identified in 295 SEM images and determined into 9 genus and 4 families. Median pollen grain concentrations/deformities were 9m-3/24%, 3m-3/18%, 8m-3/50% for Prague, Brezno and Láz localities respectively. The pollen grains of the Poaceae family were found with the highest frequency in all localities. Number of pollen increased with total aerosol mass in Prague locality only. There were also identified brochosomes, rather unique insect secretion products, in the samples from the Láz locality.

Atmospheric conditions during high ragweed pollen concentrations in Zagreb, Croatia.

PubMed

Prtenjak, Maja Telišman; Srnec, Lidija; Peternel, Renata; Madžarević, Valentina; Hrga, Ivana; Stjepanović, Barbara

2012-11-01

We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (> 600 grains/m(3)) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m(3). Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

Atmospheric conditions during high ragweed pollen concentrations in Zagreb, Croatia

NASA Astrophysics Data System (ADS)

Prtenjak, Maja Telišman; Srnec, Lidija; Peternel, Renata; Madžarević, Valentina; Hrga, Ivana; Stjepanović, Barbara

2012-11-01

We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (> 600 grains/m3) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m3. Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

It is a matter of timing: asynchrony during pollen development and its consequences on pollen performance in angiosperms-a review.

PubMed

Carrizo García, Carolina; Nepi, Massimo; Pacini, Ettore

2017-01-01

Functional pollen is needed to successfully complete fertilization. Pollen is formed inside the anthers following a specific sequence of developmental stages, from microsporocyte meiosis to pollen release, that concerns microsporocytes/microspores and anther wall tissues. The processes involved may not be synchronous within a flower, an anther, and even a microsporangium. Asynchrony has been barely analyzed, and its biological consequences have not been yet assessed. In this review, different processes of pollen development and lifetime, stressing on the possible consequences of their differential timing on pollen performance, are summarized. Development is usually synchronized until microsporocyte meiosis I (occasionally until meiosis II). Afterwards, a period of mostly asynchronous events extends up to anther opening as regards: (1) meiosis II (sometimes); (2) microspore vacuolization and later reduction of vacuoles; (3) amylogenesis, amylolysis, and carbohydrate inter-conversion; (4) the first haploid mitosis; and (5) intine formation. Asynchrony would promote metabolic differences among developing microspores and therefore physiologically heterogeneous pollen grains within a single microsporangium. Asynchrony would increase the effect of competition for resources during development and pollen tube growth and also for water during (re)hydration on the stigma. The differences generated by developmental asynchronies may have an adaptive role since more efficient pollen grains would be selected with regard to homeostasis, desiccation tolerance, resilience, speed of (re)hydration, and germination. The performance of each pollen grain which landed onto the stigma will be the result of a series of selective steps determined by its development, physiological state at maturity, and successive environmental constrains.

Pollen limitation of reproductive effort in willows.

PubMed

Fox, John F

1992-05-01

Pollen limitation of seed set differs from resource limitation in its implications for the evolution of floral traits. Willow flowers attract insects, but also abundantly produce wind-dispersed pollen. I demonstrated pollen limitation in single branches bearing 2-4 inflorescences (catkins) in a field experiment with five species by artificially increasing or decreasing the pollen load. Because the responses by single branches might be explained by diversion of resources to better-pollinated branches within a plant, a second experiment with one species tested both pollen limitation of whole plants and the autonomy of catkins. Seed set of single willow catkins is unaffected by experimental alterations of seed set in other catkins on the same plant. Hand-pollination of single catkins and of whole plants increased seed set to the same degree, suggesting there is little or no competition for resources between catkins only 5-10 cm apart. Thus, seed set in willows appears to be pollen limited, favoring insect pollination and the evolution of entomophilous traits. The data support previous views that willows have a dual pollination system utilizing wind and insects.

Pollen-mediated gene flow in wheat (Triticum aestivum L.) in a semiarid field environment in Spain.

PubMed

Loureiro, Iñigo; Escorial, María-Concepción; González, Águeda; Chueca, María-Cristina

2012-12-01

Transgenic wheat (Triticum aestivum L.) varieties are being developed and field-tested in various countries. Concerns regarding gene flow from genetically modified (GM) crops to non-GM crops have stimulated research to estimate outcrossing in wheat prior to the release and commercialization of any transgenic cultivars. The aim is to ensure that coexistence of all types of wheat with GM wheat is feasible in accordance with current regulations. The present study describes the result of a field experiment under the semi-arid climate conditions of Madrid, Spain, at two locations ("La Canaleja" and "El Encin" experimental stations) in Madrid over a 3-year period, from 2005 to 2007. The experimental design consisted of a 50 × 50 m wheat pollen source sown with wheat cultivars resistant to the herbicide chlortoluron ('Deganit' and 'Castan' respectively) and three susceptible receptor cultivars ('Abental', 'Altria' and 'Recital') sown in replicated 1 × 1 m plots at different distances (0, 1, 3, 5, 10, 20, 40, 80 and 100 m) and four directions. Outcrossing rates were measured as a percentage of herbicide-resistant hybrids using an herbicide-screening assay. Outcrossing was greatest near the pollen source, averaging 0.029% at 0 m distance at "La Canaleja" and 0.337% at "El Encin", both below the 0.9% European Union regulated threshold, although a maximum outcrossing rate of 3.5% was detected in one recipient plot. These percentages declined rapidly as the distance increased, but hybrids were detected at different rates at distances of up to 100 m, the maximum distance of the experiment. Environmental conditions, as drought in 2004-2005 and 2005-2006, may have influenced the extent of outcrossing. These assays carried out in wheat under semi-arid conditions in Europe provide a more complete assessment of pollen-mediated gene flow in this crop.

Plant and Insect Viruses in Managed and Natural Environments: Novel and Neglected Transmission Pathways.

PubMed

Jones, Roger A C

2018-01-01

The capacity to spread by diverse transmission pathways enhances a virus' ability to spread effectively and survive when circumstances change. This review aims to improve understanding of how plant and insect viruses spread through natural and managed environments by drawing attention to 12 novel or neglected virus transmission pathways whose contribution is underestimated. For plant viruses, the pathways reviewed are vertical and horizontal transmission via pollen, and horizontal transmission by parasitic plants, natural root grafts, wind-mediated contact, chewing insects, and contaminated water or soil. For insect viruses, they are transmission by plants serving as passive "vectors," arthropod vectors, and contamination of pollen and nectar. Based on current understanding of the spatiotemporal dynamics of virus spread, the likely roles of each pathway in creating new primary infection foci, enlarging previously existing infection foci, and promoting generalized virus spread are estimated. All pathways except transmission via parasitic plants, root grafts, and wind-mediated contact transmission are likely to produce new primary infection foci. All 12 pathways have the capability to enlarge existing infection foci, but only to a limited extent when spread occurs via virus-contaminated soil or vertical pollen transmission. All pathways except those via parasitic plant, root graft, contaminated soil, and vertical pollen transmission likely contribute to generalized virus spread, but to different extents. For worst-case scenarios, where mixed populations of host species occur under optimal virus spread conditions, the risk that host species jumps or virus emergence events will arise is estimated to be "high" for all four insect virus pathways considered, and, "very high" or "moderate" for plant viruses transmitted by parasitic plant and root graft pathways, respectively. To establish full understanding of virus spread and thereby optimize effective virus disease management, it is important to examine all transmission pathways potentially involved, regardless of whether the virus' ecology is already presumed to be well understood or otherwise. © 2018 Elsevier Inc. All rights reserved.

Molecular analysis confirms the long-distance transport of Juniperus ashei pollen

PubMed Central

Mohanty, Rashmi Prava; Buchheim, Mark Alan; Anderson, James; Levetin, Estelle

2017-01-01

Although considered rare, airborne pollen can be deposited far from its place of origin under a confluence of favorable conditions. Temporally anomalous records of Cupressacean pollen collected from January air samples in London, Ontario, Canada have been cited as a new case of long-distance transport. Data on pollination season implicated Juniperus ashei (mountain cedar), with populations in central Texas and south central Oklahoma, as the nearest source of the Cupressacean pollen in the Canadian air samples. This finding is of special significance given the allergenicity of mountain cedar pollen. While microscopy is used extensively to identify particles in the air spora, pollen from all members of the Cupressaceae, including Juniperus, are morphologically indistinguishable. Consequently, we implemented a molecular approach to characterize Juniperus pollen using PCR in order to test the long-distance transport hypothesis. Our PCR results using species-specific primers confirmed that the anomalous Cupressacean pollen collected in Canada was from J. ashei. Forward trajectory analysis from source areas in Texas and the Arbuckle Mountains in Oklahoma and backward trajectory analysis from the destination area near London, Ontario were completed using models implemented in HYSPLIT4 (Hybrid Single-Particle Lagrangian Integrated Trajectory). Results from these trajectory analyses strongly supported the conclusion that the J. ashei pollen detected in Canada had its origins in Texas or Oklahoma. The results from the molecular findings are significant as they provide a new method to confirm the long-distance transport of pollen that bears allergenic importance. PMID:28273170

Regional forecast model for the Olea pollen season in Extremadura (SW Spain).

PubMed

Fernández-Rodríguez, Santiago; Durán-Barroso, Pablo; Silva-Palacios, Inmaculada; Tormo-Molina, Rafael; Maya-Manzano, José María; Gonzalo-Garijo, Ángela

2016-10-01

The olive tree (Olea europaea) is a predominantly Mediterranean anemophilous species. The pollen allergens from this tree are an important cause of allergic problems. Olea pollen may be relevant in relation to climate change, due to the fact that its flowering phenology is related to meteorological parameters. This study aims to investigate airborne Olea pollen data from a city on the SW Iberian Peninsula, to analyse the trends in these data and their relationships with meteorological parameters using time series analysis. Aerobiological sampling was conducted from 1994 to 2013 in Badajoz (SW Spain) using a 7-day Hirst-type volumetric sampler. The main Olea pollen season lasted an average of 34 days, from May 4th to June 7th. The model proposed to forecast airborne pollen concentrations, described by one equation. This expression is composed of two terms: the first term represents the resilience of the pollen concentration trend in the air according to the average concentration of the previous 10 days; the second term was obtained from considering the actual pollen concentration value, which is calculated based on the most representative meteorological variables multiplied by a fitting coefficient. Due to the allergenic characteristics of this pollen type, it should be necessary to forecast its short-term prevalence using a long record of data in a city with a Mediterranean climate. The model obtained provides a suitable level of confidence to forecast Olea airborne pollen concentration.

Regional forecast model for the Olea pollen season in Extremadura (SW Spain)

NASA Astrophysics Data System (ADS)

Fernández-Rodríguez, Santiago; Durán-Barroso, Pablo; Silva-Palacios, Inmaculada; Tormo-Molina, Rafael; Maya-Manzano, José María; Gonzalo-Garijo, Ángela

2016-10-01

The olive tree ( Olea europaea) is a predominantly Mediterranean anemophilous species. The pollen allergens from this tree are an important cause of allergic problems. Olea pollen may be relevant in relation to climate change, due to the fact that its flowering phenology is related to meteorological parameters. This study aims to investigate airborne Olea pollen data from a city on the SW Iberian Peninsula, to analyse the trends in these data and their relationships with meteorological parameters using time series analysis. Aerobiological sampling was conducted from 1994 to 2013 in Badajoz (SW Spain) using a 7-day Hirst-type volumetric sampler. The main Olea pollen season lasted an average of 34 days, from May 4th to June 7th. The model proposed to forecast airborne pollen concentrations, described by one equation. This expression is composed of two terms: the first term represents the resilience of the pollen concentration trend in the air according to the average concentration of the previous 10 days; the second term was obtained from considering the actual pollen concentration value, which is calculated based on the most representative meteorological variables multiplied by a fitting coefficient. Due to the allergenic characteristics of this pollen type, it should be necessary to forecast its short-term prevalence using a long record of data in a city with a Mediterranean climate. The model obtained provides a suitable level of confidence to forecast Olea airborne pollen concentration.

The long distance transport of airborne Ambrosia pollen to the UK and the Netherlands from Central and south Europe

NASA Astrophysics Data System (ADS)

de Weger, Letty A.; Pashley, Catherine H.; Šikoparija, Branko; Skjøth, Carsten A.; Kasprzyk, Idalia; Grewling, Łukasz; Thibaudon, Michel; Magyar, Donat; Smith, Matt

2016-12-01

The invasive alien species Ambrosia artemisiifolia (common or short ragweed) is increasing its range in Europe. In the UK and the Netherlands, airborne concentrations of Ambrosia pollen are usually low. However, more than 30 Ambrosia pollen grains per cubic metre of air (above the level capable to trigger allergic symptoms) were recorded in Leicester (UK) and Leiden (NL) on 4 and 5 September 2014. The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the episode could be the result of long distance transport, to identify the potential sources of these pollen grains and to describe the conditions that facilitated this possible long distance transport. Airborne Ambrosia pollen data were collected at 10 sites in Europe. Back trajectory and atmospheric dispersion calculations were performed using HYSPLIT_4. Back trajectories calculated at Leicester and Leiden show that higher altitude air masses (1500 m) originated from source areas on the Pannonian Plain and Ukraine. During the episode, air masses veered to the west and passed over the Rhône Valley. Dispersion calculations showed that the atmospheric conditions were suitable for Ambrosia pollen released from the Pannonian Plain and the Rhône Valley to reach the higher levels and enter the airstream moving to northwest Europe where they were deposited at ground level and recorded by monitoring sites. The study indicates that the Ambrosia pollen grains recorded during the episode in Leicester and Leiden were probably not produced by local sources but transported long distances from potential source regions in east Europe, i.e. the Pannonian Plain and Ukraine, as well as the Rhône Valley in France.

Thermoregulation of dancing bees: thoracic temperature of pollen and nectar foragers in relation to profitability of foraging and colony need.

PubMed

Stabentheiner, A

2001-04-01

The thorax surface temperature of dancing honeybees (Apis mellifera carnica) recruiting nestmates to natural sources of nectar and pollen around Graz (Austria) was measured by real-time infrared thermography without touching them or disturbing social interactions. Thorax temperature during dancing was quite variable (31.4-43 degrees C). In the course of a foraging season it varied considerably and was always lower than in bees foraging from a highly profitable food source (2 molar sucrose 120 m from the hive). It averaged 38.0 degrees C (SD=2.24, n=224 dances) in the nectar foragers and 37.4 degrees C (SD=1.64, n=171) in the pollen foragers, resembling that of dancers foraging 0.5 molar sucrose from feeders with unlimited flow. Hive air temperature accounted only for about 3-8% of total variation. Foraging distance modulated dancing temperature in a way that, according to the decrease of the profitability of foraging with distance, maximum temperatures decreased and, in accordance with the increase of the dancing threshold with distance, minumum temperatures increased with distance, this way providing new support for the hypothesis that the dancing temperature is modulated by the profitability of foraging and the dancing and foraging motivation of the bees. Dancing temperature of both nectar and pollen dancers correlated with several parameters of the hive status, increasing with the amount of brood and decreasing with the amount of honey and pollen. These correlations are discussed with respect to literature reports on a colony's need for pollen and nectar, in particular the effect of brood and the amount of pollen on pollen foraging, and the effect of honey stores and demand for nectar on nectar foraging.

KNS4/UPEX1: A Type II Arabinogalactan β-(1,3)-Galactosyltransferase Required for Pollen Exine Development1[OPEN

PubMed Central

Suzuki, Toshiya; Narciso, Joan Oñate; Zeng, Wei; van de Meene, Allison; Yasutomi, Masayuki; Takemura, Shunsuke

2017-01-01

Pollen exine is essential for protection from the environment of the male gametes of seed-producing plants, but its assembly and composition remain poorly understood. We previously characterized Arabidopsis (Arabidopsis thaliana) mutants with abnormal pollen exine structure and morphology that we named kaonashi (kns). Here we describe the identification of the causal gene of kns4 that was found to be a member of the CAZy glycosyltransferase 31 gene family, identical to UNEVEN PATTERN OF EXINE1, and the biochemical characterization of the encoded protein. The characteristic exine phenotype in the kns4 mutant is related to an abnormality of the primexine matrix laid on the surface of developing microspores. Using light microscopy with a combination of type II arabinogalactan (AG) antibodies and staining with the arabinogalactan-protein (AGP)-specific β-Glc Yariv reagent, we show that the levels of AGPs in the kns4 microspore primexine are considerably diminished, and their location differs from that of wild type, as does the distribution of pectin labeling. Furthermore, kns4 mutants exhibit reduced fertility as indicated by shorter fruit lengths and lower seed set compared to the wild type, confirming that KNS4 is critical for pollen viability and development. KNS4 was heterologously expressed in Nicotiana benthamiana, and was shown to possess β-(1,3)-galactosyltransferase activity responsible for the synthesis of AG glycans that are present on both AGPs and/or the pectic polysaccharide rhamnogalacturonan I. These data demonstrate that defects in AGP/pectic glycans, caused by disruption of KNS4 function, impact pollen development and viability in Arabidopsis. PMID:27837085

The Tension-sensitive Ion Transport Activity of MSL8 is Critical for its Function in Pollen Hydration and Germination.

PubMed

Hamilton, Eric S; Haswell, Elizabeth S

2017-07-01

All cells respond to osmotic challenges, including those imposed during normal growth and development. Mechanosensitive (MS) ion channels provide a conserved mechanism for regulating osmotic forces by conducting ions in response to increased membrane tension. We previously demonstrated that the MS ion channel MscS-Like 8 (MSL8) is required for pollen to survive multiple osmotic challenges that occur during the normal process of fertilization, and that it can inhibit pollen germination. However, it remained unclear whether these physiological functions required ion flux through a mechanically gated channel provided by MSL8. We introduced two point mutations into the predicted pore-lining domain of MSL8 that disrupted normal channel function in different ways. The Ile711Ser mutation increased the tension threshold of the MSL8 channel while leaving conductance unchanged, and the Phe720Leu mutation severely disrupted the MSL8 channel. Both of these mutations impaired the ability of MSL8 to preserve pollen viability during hydration and to maintain the integrity of the pollen tube when expressed at endogenous levels. When overexpressed in an msl8-4 null background, MSL8I711S could partially rescue loss-of-function phenotypes, while MSL8F720L could not. When overexpressed in the wild-type Ler background, MSL8I711S suppressed pollen germination, similar to wild-type MSL8. In contrast, MSL8F720L failed to suppress pollen germination and increased pollen bursting, thereby phenocopying the msl8-4 mutant. Thus, an intact MSL8 channel is required for normal pollen function during hydration and germination. These data establish MSL8 as the first plant MS channel to fulfill previously established criteria for assignment as a mechanotransducer. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Calcium dynamics in tomato pollen tubes using the Yellow Cameleon 3.6 sensor.

PubMed

Barberini, María Laura; Sigaut, Lorena; Huang, Weijie; Mangano, Silvina; Juarez, Silvina Paola Denita; Marzol, Eliana; Estevez, José; Obertello, Mariana; Pietrasanta, Lía; Tang, Weihua; Muschietti, Jorge

2018-06-01

In vitro tomato pollen tubes show a cytoplasmic calcium gradient that oscillates with the same period as growth. Pollen tube growth requires coordination between the tip-focused cytoplasmic calcium concentration ([Ca 2+ ] cyt ) gradient and the actin cytoskeleton. This [Ca 2+ ] cyt gradient is necessary for exocytosis of small vesicles, which contributes to the delivery of new membrane and cell wall at the pollen tube tip. The mechanisms that generate and maintain this [Ca 2+ ] cyt gradient are not completely understood. Here, we studied calcium dynamics in tomato (Solanum lycopersicum) pollen tubes using transgenic tomato plants expressing the Yellow Cameleon 3.6 gene under the pollen-specific promoter LAT52. We use tomato as an experimental model because tomato is a Solanaceous plant that is easy to transform, and has an excellent genomic database and genetic stock center, and unlike Arabidopsis, tomato pollen is a good system to do biochemistry. We found that tomato pollen tubes showed an oscillating tip-focused [Ca 2+ ] cyt gradient with the same period as growth. Then, we used a pharmacological approach to disturb the intracellular Ca 2+ homeostasis, evaluating how the [Ca 2+ ] cyt gradient, pollen germination and in vitro pollen tube growth were affected. We found that cyclopiazonic acid (CPA), a drug that inhibits plant P IIA -type Ca 2+ -ATPases, increased [Ca 2+ ] cyt in the subapical zone, leading to the disappearance of the Ca 2+ oscillations and inhibition of pollen tube growth. In contrast, 2-aminoethoxydiphenyl borate (2-APB), an inhibitor of Ca 2+ released from the endoplasmic reticulum to the cytoplasm in animals cells, completely reduced [Ca 2+ ] cyt at the tip of the tube, blocked the gradient and arrested pollen tube growth. Although both drugs have antagonistic effects on [Ca 2+ ] cyt , both inhibited pollen tube growth triggering the disappearance of the [Ca 2+ ] cyt gradient. When CPA and 2-APB were combined, their individual inhibitory effects on pollen tube growth were partially compensated. Finally, we found that GsMTx-4, a peptide from spider venom that blocks stretch-activated Ca 2+ channels, inhibited tomato pollen germination and had a heterogeneous effect on pollen tube growth, suggesting that these channels are also involved in the maintenance of the [Ca 2+ ] cyt gradient. All these results indicate that tomato pollen tube is an excellent model to study calcium dynamics.

Short-term effects of airborne pollens on asthma attacks as seen by general practitioners in the Greater Paris area, 2003-2007.

PubMed

Huynh, Bich Tram; Tual, Séverine; Turbelin, Clément; Pelat, Camille; Cecchi, Lorenzo; D'Amato, Gennaro; Blanchon, Thierry; Annesi-Maesano, Isabella

2010-09-01

To investigate for the first time the short-term effects of airborne pollen counts on general practitioner (GP) consultations for asthma attacks in the Greater Paris area between 2003-2007. Counts were available for common pollens (Betula, Cupressa, Fraxinus and Poaceae). Weekly data on GP visits for asthma attacks were obtained from the French GP Sentinel Network. A quasi-Poisson regression with generalised additive models was implemented. Short-term effects of pollen counts were assessed using single and multi-pollen models after adjustment for air pollution and influenza. A mean weekly incidence rate of 25.4 cases of asthma attacks per 100,000 inhabitants was estimated during the study period. The strongest significant association between asthma attacks and pollen counts was registered for grass (Poaceae) in the same week of asthma attacks, with a slight reduction of the effect observed in the multi-pollen model. Adjusted relative risk for Poaceae was 1.54 (95% CI: 1.33-1.79) with an inter-quartile range increase of 17.6 grains/m3 during the pollen season. For the first time, a significant short-term association was observed between Poaceae pollen counts and consultations for asthma attacks as seen by GPs. These findings need to be confirmed by more consistent time-series and investigations on a daily basis.

Pollen specific expression of maize genes encoding actin depolymerizing factor-like proteins.

PubMed Central

Lopez, I; Anthony, R G; Maciver, S K; Jiang, C J; Khan, S; Weeds, A G; Hussey, P J

1996-01-01

In pollen development, a dramatic reorganization of the actin cytoskeleton takes place during the passage of the pollen grain into dormancy and on activation of pollen tube growth. A role for actin-binding proteins is implicated and we report here the identification of a small gene family in maize that encodes actin depolymerizing factor (ADF)-like proteins. The ADF group of proteins are believed to control actin polymerization and depolymerization in response to both intracellular and extracellular signals. Two of the maize genes ZmABP1 and ZmABP2 are expressed specifically in pollen and germinating pollen suggesting that the protein products may be involved in pollen actin reorganization. A third gene, ZmABP3, encodes a protein only 56% and 58% identical to ZmABP1 and ZmABP2, respectively, and its expression is suppressed in pollen and germinated pollen. The fundamental biochemical characteristics of the ZmABP proteins has been elucidated using bacterially expressed ZmABP3 protein. This has the ability to bind monomeric actin (G-actin) and filamentous actin (F-actin). Moreover, it decreases the viscosity of polymerized actin solutions consistent with an ability to depolymerize filaments. These biochemical characteristics, taken together with the sequence comparisons, support the inclusion of the ZmABP proteins in the ADF group. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8693008

Innate responses to putative ancestral hosts: is the attraction of Western flower thrips to pine pollen a result of relict olfactory receptors?

PubMed

Abdullah, Zayed S; Ficken, Katherine J; Greenfield, Bethany P J; Butt, Tariq M

2014-06-01

Pollinophagy is widely documented in the order Thysanoptera, with representative individuals from six of the nine divergent families known to feed on pollen. Various pollens of the genus Pinus increase the development time, fecundity, longevity, and settling preference of Western Flower Thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Certain species of flower thrips discriminate among pollen types, but no studies have elucidated the olfactory cues that play a role in their pollen preferences. In this study, the volatile organic compounds emitted by pollens of the genus Pinus were elucidated. Various chemicals from pollen headspace elicited electrophysiological responses from WFT antennae. The compound (S)-(-)-verbenone, identified in pollen headspace, attracted WFT in a 4-arm olfactometer. This compound has potential for use in integrated pest management programs against the pest. We present the hypothesis that this polyphagous insect may have retained ancestral 'relict' olfactory receptors through the course of evolution, to explain this attraction to pine pollen. This attraction has allowed the insect to find and exploit an unusual nutrient source that significantly increases its fitness. The study demonstrates how fossil record analysis and subsequent evolutionary knowledge can aid in explaining possibilities as to why some insects sense and respond to chemicals that would otherwise seem peculiar to their ecology, allowing insight into the evolutionary forces that may shape insect olfactory systems over time.

PECTATE LYASE-LIKE10 is associated with pollen wall development in Brassica campestris.

PubMed

Jiang, Jingjing; Yao, Lina; Yu, Youjian; Lv, Meiling; Miao, Ying; Cao, Jiashu

2014-11-01

PECTATE LYASE-LIKE10 (PLL10) was previously identified as one of the differentially expressed genes both in microspores during the late pollen developmental stages and in pistils during the fertilization process in Chinese cabbage (Brassica campestris ssp. chinensis). Here, antisense-RNA was used to study the functions of BcPLL10 in Chinese cabbage. Abnormal pollen was identified in the transgenic lines (bcpll10-4, -5, and -6). In fertilization experiments, fewer seeds were harvested when the antisense-RNA lines were used as pollen donor. In vivo and in vitro pollen germination assays less germinated pollen tubes were observed in bcpll10 lines. Scanning electron microscopy observation verified that the tryphine materials were over accumulated around the pollen surface and sticked them together in bcpll10. Moreover, transmission electron microscopy observation revealed that the internal endintine was overdeveloped and predominantly occupied the intine, and disturbed the normal proportional distribution of the two layers in the non-germinal furrow region; and no obvious demarcation existed between them in the germinal furrow region in the bcpll10 pollen. Collectively, this study presented a novel PLL gene that played an important role during the pollen wall development in B. campestris, which may also possess potential importance for male sterility usage in agriculture. © 2014 Institute of Botany, Chinese Academy of Sciences.

Study on the inhibition of Mfn1 by plant-derived miR5338 mediating the treatment of BPH with rape bee pollen.

PubMed

Chen, Xuan; Wu, Ren-Zhao; Zhu, Yong-Qiang; Ren, Ze-Ming; Tong, Ye-Ling; Yang, Feng; Dai, Guan-Hai

2018-01-30

Recent studies have found that plant derived microRNA can cross-kingdom regulate the expression of genes in humans and other mammals, thereby resisting diseases. Can exogenous miRNAs cross the blood-prostate barrier and entry prostate then participate in prostate disease treatment? Using HiSeq sequencing and RT-qPCR technology, we detected plant miRNAs that enriched in the prostates of rats among the normal group, BPH model group and rape bee pollen group. To forecast the functions of these miRNAs, the psRobot software and TargetFinder software were used to predict their candidate target genes in rat genome. The qRT-PCR technology was used to validate the expression of candidate target genes. Plant miR5338 was enriched in the posterior lobes of prostate gland of rats fed with rape bee pollen, which was accompanied by the improvement of BPH. Among the predicted target genes of miR5338, Mfn1 was significantly lower in posterior lobes of prostates of rats in the rape bee pollen group than control groups. Further experiments suggested that Mfn1 was highly related to BPH. These results suggesting that plant-derived miR5338 may involve in treatment of rat BPH through inhibiting Mfn1 in prostate. These results will provide more evidence for plant miRNAs cross-kingdom regulation of animal gene, and will provide preliminary theoretical and experimental basis for development of rape bee pollen into innovative health care product or medicine for the treatment of BPH.

Dynamic ecological observations from satellites inform aerobiology of allergenic grass pollen.

PubMed

Devadas, Rakhesh; Huete, Alfredo R; Vicendese, Don; Erbas, Bircan; Beggs, Paul J; Medek, Danielle; Haberle, Simon G; Newnham, Rewi M; Johnston, Fay H; Jaggard, Alison K; Campbell, Bradley; Burton, Pamela K; Katelaris, Constance H; Newbigin, Ed; Thibaudon, Michel; Davies, Janet M

2018-08-15

Allergic diseases, including respiratory conditions of allergic rhinitis (hay fever) and asthma, affect up to 500 million people worldwide. Grass pollen are one major source of aeroallergens globally. Pollen forecast methods are generally site-based and rely on empirical meteorological relationships and/or the use of labour-intensive pollen collection traps that are restricted to sparse sampling locations. The spatial and temporal dynamics of the grass pollen sources themselves, however, have received less attention. Here we utilised a consistent set of MODIS satellite measures of grass cover and seasonal greenness (EVI) over five contrasting urban environments, located in Northern (France) and Southern Hemispheres (Australia), to evaluate their utility for predicting airborne grass pollen concentrations. Strongly seasonal and pronounced pollinating periods, synchronous with satellite measures of grass cover greenness, were found at the higher latitude temperate sites in France (46-50° N. Lat.), with peak pollen activity lagging peak greenness, on average by 2-3weeks. In contrast, the Australian sites (34-38° S. Lat.) displayed pollinating periods that were less synchronous with satellite greenness measures as peak pollen concentrations lagged peak greenness by as much as 4 to 7weeks. The Australian sites exhibited much higher spatial and inter-annual variations compared to the French sites and at the Sydney site, broader and multiple peaks in both pollen concentrations and greenness data coincided with flowering of more diverse grasses including subtropical species. Utilising generalised additive models (GAMs) we found the satellite greenness data of grass cover areas explained 80-90% of airborne grass pollen concentrations across the three French sites (p<0.001) and accounted for 34 to 76% of grass pollen variations over the two sites in Australia (p<0.05). Our results demonstrate the potential of satellite sensing to augment forecast models of grass pollen aerobiology as a tool to reduce the health and socioeconomic burden of pollen-sensitive allergic diseases. Copyright © 2018 Elsevier B.V. All rights reserved.

Intra- and extracellular lipid composition and associated gene expression patterns during pollen development in Brassica napus.

PubMed

Piffanelli, P; Ross, J H; Murphy, D J

1997-03-01

Pollen development in angiosperms is regulated by the interaction of products contributed by both the gametophytic (haploid) and sporophytic (diploid) genomes. In entomophilous species, lipids are major products of both sporophytic and gametophytic metabolism during pollen development. Mature pollen grains of Brassica napus are shown to contain three major acyl lipid pools as follows: (i) the extracellular tryphine mainly consisting of medium-chain neutral esters; (ii) the intracellular membranes, particularly endoplasmic reticulum, mainly containing phospholipids; and (iii) the intracellular storage lipids, which are mostly triacylglycerols. This paper reports on the kinetics of accumulation of these lipid classes during pollen maturation and the expression patterns of several lipid biosynthetic genes and their protein products that are differentially regulated in developing microspores/ pollen grains (gametophyte) and tapetal cells (sporophyte) of B. napus. Detailed analysis of three members of the stearoyl-ACP desaturase (sad) gene family by Northern blotting, in situ hybridization and RT-PCR showed that the same individual genes were expressed both in gametophytic and sporophytic tissues, although under different temporal regulation. In the tapetum, maximal expression of two marker genes for lipid biosynthesis (sad and ear) occurred at a bud length of 2-3 mm, and the corresponding gene products SAD and EAR were detected by Western blotting in 3-4 mm buds, coinciding with the maximal rates of tapetal lipid accumulation. These lipids are released following tapetal cell disintegration and are relocated to form the major structural component of the extracellular tryphine layer that coats the mature pollen grain. In contrast, in developing microspores/pollen grains, maximal expression of the lipid marker genes sad, ear, acp and cyb5 was at the 3-5 mm bud stages, with the SAD and EAR gene products detected in 4-7 mm buds. This pattern of expression coincided with accumulation of the intracellular storage and membrane lipid components of pollen. These results suggest that, although the same genes may be expressed in the sporophytic tapetal cells and in gametophytic tissues, they are regulated differentially leading to the production of the various contrasting lipidic structures that are assembled together to give rise to a viable, fertile pollen grain.

Safety of ultrashort-term sit with pollen allergoids adjuvanted by monophosphoryl lipid A: a prospective Italian survey.

PubMed

Crivellaro, M; Senna, G E; Pappacoda, A; Vanzelli, R; Spacal, B; Marchi, G; Recchia, G; Makatsori, M

2011-03-01

A 3-year prospective post marketing survey on the safety of the recently developed ultrashort pre-seasonal subcutaneous immunotherapy (uSCIT-MPL4) with pollen allergoids adjuvanted with monophosphoryl lipid A was performed. A total of 510 patients received uSCIT-MPL4, 61% for grass, 35.7% for birch, 13.2% for parietaria and 3% for other pollens (ragweed, mugwort, and olive). A total of 3308 injections were given and the mean duration of uSCIT-MPL-4 was 2.3 years. Overall, only 7 slight systemic reactions (SR) were observed in 510 patients (1.37%) and 2.11/1000 injections suggesting that this treatment is even safer than traditional depot injection SIT.

Trehalase: A New Pollen Enzyme

PubMed Central

Gussin, Arnold E. S.; McCormack, Jeffrey H.; Waung, Lucille Yih-Lo; Gluckin, Doreen S.

1969-01-01

Pollen from 5 plant species (Lycopersicon pimpinellifolium Mill., Hermerocallis minor Mill., Galtonia condicans Decne., Camellia japonica L., and Lathyrus odoratus L.) representing 4 families germinated well in media containing trehalose as the sole carbon source. Data are presented indicating that pollen metabolized this disaccharide for germination and subsequent pollen-tube growth; the sugar was not merely an osmoregulator. An inhibitor of trehalase activity depressed germination in trehalose but not in sucrose. Phloridzin dihydrate, an inhibitor of glucose transport, depressed germination in both disaccharides. Biochemical tests demonstrated that a pollen extract was capable of hydrolyzing trehalose to its constituent glucose monomers. Heat inactivation experiments confirmed the presence of a distinct trehalase having a rigid specificity for its substrate. By this method, trehalase activity was completely distinguishable from the activities of other α- and β-glucosidases and β-galactosidases. Localization data indicated that the enzyme diffused from intact grains and was probably soluble. The presence of its substrate could not be demonstrated in pollen or in stigmatic or stylar tissues. PMID:5379538

Trehalase: a new pollen enzyme.

PubMed

Gussin, A E; McCormack, J H; Waung, L Y; Gluckin, D S

1969-08-01

Pollen from 5 plant species (Lycopersicon pimpinellifolium Mill., Hermerocallis minor Mill., Galtonia condicans Decne., Camellia japonica L., and Lathyrus odoratus L.) representing 4 families germinated well in media containing trehalose as the sole carbon source. Data are presented indicating that pollen metabolized this disaccharide for germination and subsequent pollen-tube growth; the sugar was not merely an osmoregulator. An inhibitor of trehalase activity depressed germination in trehalose but not in sucrose. Phloridzin dihydrate, an inhibitor of glucose transport, depressed germination in both disaccharides. Biochemical tests demonstrated that a pollen extract was capable of hydrolyzing trehalose to its constituent glucose monomers. Heat inactivation experiments confirmed the presence of a distinct trehalase having a rigid specificity for its substrate. By this method, trehalase activity was completely distinguishable from the activities of other alpha- and beta-glucosidases and beta-galactosidases. Localization data indicated that the enzyme diffused from intact grains and was probably soluble. The presence of its substrate could not be demonstrated in pollen or in stigmatic or stylar tissues.

Pollen analysis of natural honeys from the central region of Shanxi, North China.

PubMed

Song, Xiao-Yan; Yao, Yi-Feng; Yang, Wu-De

2012-01-01

Based on qualitative and quantitative melissopalynological analyses, 19 Chinese honeys were classified by botanical origin to determine their floral sources. The honey samples were collected during 2010-2011 from the central region of Shanxi Province, North China. A diverse spectrum of 61 pollen types from 37 families was identified. Fourteen samples were classified as unifloral, whereas the remaining samples were multifloral. Bee-favoured families (occurring in more than 50% of the samples) included Caprifoliaceae (found in 10 samples), Laminaceae (10), Brassicaceae (12), Rosaceae (12), Moraceae (13), Rhamnaceae (15), Asteraceae (17), and Fabaceae (19). In the unifloral honeys, the predominant pollen types were Ziziphus jujuba (in 5 samples), Robinia pseudoacacia (3), Vitex negundo var. heterophylla (2), Sophora japonica (1), Ailanthus altissima (1), Asteraceae type (1), and Fabaceae type (1). The absolute pollen count (i.e., the number of pollen grains per 10 g honey sample) suggested that 13 samples belonged to Group I (<20,000 pollen grains), 4 to Group II (20,000-100,000), and 2 to Group III (100,000-500,000). The dominance of unifloral honeys without toxic pollen grains and the low value of the HDE/P ratio (i.e., honey dew elements/pollen grains from nectariferous plants) indicated that the honey samples are of good quality and suitable for human consumption.

Pollen and seed mediated gene flow in commercial alfalfa seed production fields

USDA-ARS?s Scientific Manuscript database

The potential for gene flow has been widely recognized since alfalfa is pollinated by bees. The Western US is a major exporter of alfalfa seed and hay and the organic dairy industry is one of the fastest growing agricultural sectors. Because of this, many alfalfa producers are impacted by market sen...

Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies

PubMed Central

Stanley-Horn, Diane E.; Dively, Galen P.; Hellmich, Richard L.; Mattila, Heather R.; Sears, Mark K.; Rose, Robyn; Jesse, Laura C. H.; Losey, John E.; Obrycki, John J.; Lewis, Les

2001-01-01

Survival and growth of monarch larvae, Danaus plexippus (L.), after exposure to either Cry1Ab-expressing pollen from three Bacillus thuringiensis (Bt) corn (Zea mays L.) events differing in toxin expression or to the insecticide, λ-cyhalothrin, were examined in field studies. First instars exposed to low doses (≈22 grains per cm2) of event-176 pollen gained 18% less weight than those exposed to Bt11 or Mon810 pollen after a 5-day exposure period. Larvae exposed to 67 pollen grains per cm2 on milkweed leaves from within an event-176 field exhibited 60% lower survivorship and 42% less weight gain compared with those exposed to leaves from outside the field. In contrast, Bt11 pollen had no effect on growth to adulthood or survival of first or third instars exposed for 5 days to ≈55 and 97 pollen grains per cm2, respectively. Similarly, no differences in larval survivorship were observed after a 4-day exposure period to leaves with 504–586 (within fields) or 18–22 (outside the field) pollen grains per cm2 collected from Bt11 and non-Bt sweet-corn fields. However, survivorship and weight gain were drastically reduced in non-Bt fields treated with λ-cyhalothrin. The effects of Bt11 and Mon810 pollen on the survivorship of larvae feeding 14 to 22 days on milkweeds in fields were negligible. Further studies should examine the lifetime and reproductive impact of Bt11 and Mon810 pollen on monarchs after long-term exposure to naturally deposited pollen. PMID:11559839

Suicide risk in relation to air pollen counts: a study based on data from Danish registers

PubMed Central

Qin, Ping; Waltoft, Berit L; Mortensen, Preben B; Postolache, Teodor T

2013-01-01

Objectives Since the well-observed spring peak of suicide incidents coincides with the peak of seasonal aeroallergens as tree-pollen, we want to document an association between suicide and pollen exposure with empirical data from Denmark. Design Ecological time series study. Setting Data on suicide incidents, air pollen counts and meteorological status were retrieved from Danish registries. Participants 13 700 suicide incidents over 1304 consecutive weeks were obtained from two large areas covering 2.86 million residents. Primary and secondary outcome measures Risk of suicide associated with pollen concentration was assessed using a time series Poisson-generalised additive model. Results We noted a significant association between suicide risk and air pollen counts. A change of pollen counts levels from 0 to ‘10–<30’ grains/m3 air was associated with a relative risk of 1.064, that is, a 6.4% increase in weekly number of suicides in the population, and from 0 to ‘30–100’ grains, a relative risk of 1.132. The observed association remained significant after controlling for effects of region, calendar time, temperature, cloud cover and humidity. Meanwhile, we observed a significant sex difference that suicide risk in men started to rise when there was a small increase of air pollen, while the risk in women started to rise until pollen grains reached a certain level. High levels of pollen had slightly stronger effect on risk of suicide in individuals with mood disorder than those without the disorder. Conclusions The observed association between suicide risk and air pollen counts supports the hypothesis that aeroallergens, acting as immune triggers, may precipitate suicide. PMID:23793651

Clinical Significance of Component Allergens in Fagales Pollen-Sensitized Peanut Allergy in Korea

PubMed Central

Park, Kyung Hee; Son, Young Woong; Lee, Sang Chul; Jeong, Kyunguk; Sim, Da Woon; Park, Hye Jung; Lee, Sooyoung; Lee, Jae-Hyun

2016-01-01

Purpose Clinical features of peanut allergy can range from localized to systemic reactions. Because peanut and birch pollen have cross-reactivity, peanut can lead to localized allergic reaction in Fagales pollen-sensitized oral allergy syndrome (OAS) patients without peanut sensitization per se. The purpose of this study was to discriminate true peanut food allergy from cross-reactive hypersensitivity in birch-sensitized peanut allergy. Methods Birch-sensitized (n=81) and peanut anaphylaxis patients (n=12) were enrolled. Peanut-related allergic reactions and sensitization profiles were examined. Specific IgE to Fagales tree pollens (birch, oak), peanut, and their component allergens (Bet v 1, Bet v 2, Ara h 1, Ara h 2, Ara h 3, Ara h 8, and Ara h 9) were evaluated. Based on these specific IgEs and clinical features, the patients were classified into 4 groups: group 1 (Fagales pollen allergy without OAS), group 2 (Fagales pollen allergy with OAS), group 3 (OAS with peanut anaphylaxis), and group 4 (peanut anaphylaxis). Results After peanut consumption, one-third of OAS patients experienced oral symptoms not associated with peanut sensitization. Ara h 1 or Ara h 2 was positive in peanut anaphylaxis patients, whereas Ara h 8 was positive in OAS patients. There were 4 patients with both peanut anaphylaxis and OAS (group 3). Both Ara h 2 and Ara h 8 were positive in these patients. Foods associated with OAS in Korea showed unique patterns compared to Westernized countries. Conclusions Ara h 2 and Ara h 8 may be important component allergens for discriminating peanut allergy. PMID:27582401

[Prospects of molecular breeding in medical plants].

PubMed

Ma, Xiao-Jun; Mo, Chang-Ming

2017-06-01

The molecular-assisted breeding, transgenic breeding and molecular designing breeding are three development directions of plant molecular breeding. Base on these three development directions, this paper summarizes developing status and new tendency of research field of genetic linkage mapping, QTL mapping, association mapping, molecular-assisted selections, pollen-mediated transformations, agrobacterium-mediated transformations, particle gun-mediated transformations, genome editing technologies, whole-genome sequencing, transcriptome sequencing, proteome sequencing and varietal molecular designing. The objective and existing problem of medical plant molecular breeding were discussed the prospect of these three molecular breeding technologies application on medical plant molecular breeding was outlooked. Copyright© by the Chinese Pharmaceutical Association.

Various cross-reactivity of the grass pollen group 4 allergens: crystallographic study of the Bermuda grass isoallergen Cyn d 4.

PubMed

Huang, Tse-Hao; Peng, Ho-Jen; Su, Song-Nan; Liaw, Shwu-Huey

2012-10-01

The structure of Cyn d 4, the group 4 allergen from Bermuda grass, is reported at 2.15 Å resolution and is the first crystal structure of a naturally isolated pollen allergen. A conserved N-terminal segment that is only present in the large isoallergens forms extensive interactions with surrounding residues and hence greatly enhances the structural stability of the protein. Cyn d 4 contains an FAD cofactor that is covalently linked to His88 and Cys152. To date, all identified bicovalent flavoproteins are oxidases and their substrates are either sugars or secondary metabolites. A deep large hydrophobic substrate-binding cleft is present. Thus, Cyn d 4 may be an oxidase that is involved in the biosynthesis of a pollen-specific metabolite. Cyn d 4 shares ~70% sequence identity with the Pooideae group 4 allergens. Various cross-reactivities between grass pollen group 4 allergens have previously been demonstrated using sera from allergic patients. The protein surface displays an unusually large number of positively charged clusters, reflecting the high pI of ~10. 38 decapeptides that cover the solvent-accessible sequences did not show any significant IgE-binding activity using sera with high Cyn d 4 reactivity from four patients, suggesting that the IgE epitopes of Cyn d 4 are predominantly conformational in nature. Several group 4 structures were then modelled and their potential cross-reactive and species-specific IgE epitopes were proposed.

Screening and Identifying Antioxidative Components in Ginkgo biloba Pollen by DPPH-HPLC-PAD Coupled with HPLC-ESI-MS2

PubMed Central

Netrusov, A. I.; Zhou, Qingxin; Guo, Danyang; Liu, Xiaoyong; He, Hailun; Xin, Xue; Wang, Yifen; Chen, Leilei

2017-01-01

The Ginkgo biloba is one of ancient trees that exists from billions of years ago, its leaf and nut are used as herbs and foods in China, while so far its pollen does not have any application except pollination. In order to evaluate the antioxidant activity of Ginkgo biloba pollen, and rapidly screen its antioxidative components, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, total flavonoid, total phenol, and proanthocyanidin of Ginkgo biloba pollen were determined and compared with those of Ginkgo biloba leaf and nut, and the off-line DPPH-HPLC-PAD and HPLC-ESI-MS2 were applied for screening and identifying the antioxidant flavonoids in Ginkgo biloba pollen. The results showed that the DPPH scavenging ability of Ginkgo biloba pollen was much higher than Ginkgo biloba nut, but lower than Ginkgo biloba leaf, while the total content of flavonoid in Ginkgo biloba pollen was approximately 4.37 times higher than in Ginkgo biloba leaf. Further studies found that the major flavonol aglycone in Ginkgo biloba pollen was kaempferol, which accounted for 96.71% of the total aglycones (includes quercetin, kaempferol and isorhamnetin), and the main flavonoid components in Ginkgo biloba pollen were flavonoid glycosides. Finally, ten antioxidant peaks were screened and identified to be flavonoids (including kaempferol and nine flavonoid glycosides), so flavonoids were likely to be the main antioxidant components in GP, and among them, three novel kaempferol glycosides (peaks 1, 2, and 3) were found in Ginkgo biloba pollen for the first time, which had never been found in Ginkgo biloba. PMID:28095510

Use of MODIS Satellite Data to Evaluate Juniperus spp. Pollen Phenology to Support a Pollen Dispersal Model, PREAM, to Support Public Health Allergy Alerts

NASA Technical Reports Server (NTRS)

Luvall, J. C.; Sprigg, W.; Levetin, E.; Huete, A.; Nickovic, S.; Pejanovic, G. A.; Vukovic, A.; VandeWater, P.; Budge, A.; Hudspeth, W.;

Screening and Identifying Antioxidative Components in Ginkgo biloba Pollen by DPPH-HPLC-PAD Coupled with HPLC-ESI-MS2.

PubMed

Qiu, Jiying; Chen, Xiangyan; Netrusov, A I; Zhou, Qingxin; Guo, Danyang; Liu, Xiaoyong; He, Hailun; Xin, Xue; Wang, Yifen; Chen, Leilei

2017-01-01

The Ginkgo biloba is one of ancient trees that exists from billions of years ago, its leaf and nut are used as herbs and foods in China, while so far its pollen does not have any application except pollination. In order to evaluate the antioxidant activity of Ginkgo biloba pollen, and rapidly screen its antioxidative components, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, total flavonoid, total phenol, and proanthocyanidin of Ginkgo biloba pollen were determined and compared with those of Ginkgo biloba leaf and nut, and the off-line DPPH-HPLC-PAD and HPLC-ESI-MS2 were applied for screening and identifying the antioxidant flavonoids in Ginkgo biloba pollen. The results showed that the DPPH scavenging ability of Ginkgo biloba pollen was much higher than Ginkgo biloba nut, but lower than Ginkgo biloba leaf, while the total content of flavonoid in Ginkgo biloba pollen was approximately 4.37 times higher than in Ginkgo biloba leaf. Further studies found that the major flavonol aglycone in Ginkgo biloba pollen was kaempferol, which accounted for 96.71% of the total aglycones (includes quercetin, kaempferol and isorhamnetin), and the main flavonoid components in Ginkgo biloba pollen were flavonoid glycosides. Finally, ten antioxidant peaks were screened and identified to be flavonoids (including kaempferol and nine flavonoid glycosides), so flavonoids were likely to be the main antioxidant components in GP, and among them, three novel kaempferol glycosides (peaks 1, 2, and 3) were found in Ginkgo biloba pollen for the first time, which had never been found in Ginkgo biloba.

BcMF26a and BcMF26b Are Duplicated Polygalacturonase Genes with Divergent Expression Patterns and Functions in Pollen Development and Pollen Tube Formation in Brassica campestris

PubMed Central

Lyu, Meiling; Yu, Youjian; Jiang, Jingjing; Song, Limin; Liang, Ying; Ma, Zhiming; Xiong, Xingpeng; Cao, Jiashu

2015-01-01

Polygalacturonase (PG) is one of the cell wall hydrolytic enzymes involving in pectin degradation. A comparison of two highly conserved duplicated PG genes, namely, Brassica campestris Male Fertility 26a (BcMF26a) and BcMF26b, revealed the different features of their expression patterns and functions. We found that these two genes were orthologous genes of At4g33440, and they originated from a chromosomal segmental duplication. Although structurally similar, their regulatory and intron sequences largely diverged. QRT-PCR analysis showed that the expression level of BcMF26b was higher than that of BcMF26a in almost all the tested organs and tissues in Brassica campestris. Promoter activity analysis showed that, at reproductive development stages, BcMF26b promoter was active in tapetum, pollen grains, and pistils, whereas BcMF26a promoter was only active in pistils. In the subcellular localization experiment, BcMF26a and BcMF26b proteins could be localized to the cell wall. When the two genes were co-inhibited, pollen intine was formed abnormally and pollen tubes could not grow or stretch. Moreover, the knockout mutants of At4g33440 delayed the growth of pollen tubes. Therefore, BcMF26a/b can participate in the construction of pollen wall by modulating intine information and BcMF26b may play a major role in co-inhibiting transformed plants. PMID:26153985

Standardization of Weed Pollen Extracts, Japanese Hop and Mugwort, in Korea

PubMed Central

Jeong, Kyoung Yong; Son, Mina; Choi, Soo-Young; Park, Kyung Hee; Park, Hye Jung; Hong, Chein-Soo; Lee, Jae-Hyun

2016-01-01

Purpose Japanese hop (Humulus spp.) and mugwort (Artemisia spp.) are notable causes of autumn pollinosis in East Asia. However, Japanese hop and mugwort pollen extracts, which are widely used for the diagnosis, have not been standardized. This study was performed to standardize Japanese hop and mugwort pollen extracts. Materials and Methods Allergen extracts were prepared in a standardized way using locally collected Humulus japonicus and purchased Artemisia vulgaris pollens. The immunoglobulin E (IgE) reactivities of prepared extracts were compared with commercial extracts via IgE immunoblotting and inhibition analyses. Intradermal skin tests were performed to determine the bioequivalent allergy unit (BAU). Results The IgE reactive components of the extracts via IgE immunoblotting were similar to those of commercial extracts. A 11-kDa allergen showed the strongest IgE reactivity in Japanese hop, as did a 28-kDa allergen in mugwort pollen extracts. Allergenic potencies of the investigatory Japanese hop and mugwort extracts were essentially indistinguishable from the commercial ones. Sums of erythema of 50 mm by the intradermal skin test (ΣED50) were calculated to be 14.4th and 13.6th three-fold dilutions for Japanese hop and mugwort extracts, respectively. Therefore, the allergenic activity of the prepared extracts was 90827.4 BAU/mg for Japanese hop and 34412 BAU/mg for mugwort. Conclusion We produced Japanese hop and mugwort pollen extracts using a standardized method. Standardized Japanese hop and mugwort pollen extracts will facilitate the production of improved diagnostic and immunotherapeutic reagents. PMID:26847293

A Last Interglacial pollen-temperature reconstruction, central North Island, New Zealand

NASA Astrophysics Data System (ADS)

Newnham, Rewi; Alloway, Brent; McGlone, Matt; Juchnowicz, Hannah; Rees, Andrew; Wilmshurst, Janet

2017-08-01

We present new pollen-temperature reconstructions for the Last Interglacial from central North Island, New Zealand using partial least squares regression (PLS) and modern analogue technique applied with the New Zealand pre-deforestation calibration pollen dataset. The pollen-bearing organic sequence includes numerous millimetre- to decimetre- thick tephra mostly from the adjacent Tongariro Volcanic Centre and is overlain by tephric cover-beds including the c. 25.4 ka cal BP Kawakawa/Oruanui Tephra. Fine-resolution pollen and preliminary diatom analyses above and below prominent tephra layers showed that significant vegetation impact followed only the thickest ashfall event (22 cm thickness), with vegetation recovery taking several hundred years. Apart from this, changes in the longer-term pollen record are likely to be related to climate oscillations that resemble the classic five-fold subdivision of MIS 5. The warmest interval, ascribed to MIS 5e, was characterised by tall, temperate rainforest, and occurs at the base of the sequence, with mean annual temperatures reaching around 1.1 °C higher than present. Mean annual temperatures declined to ∼4 °C below present during MIS 5d and MIS 5b and were within 1-2 °C of present during MIS 5c. The PLS temperature reconstructions are corroborated by estimates derived independently from elevational changes to vegetation communities, corresponding to modern temperature controls, inferred from the Karioi pollen spectra. Temperatures reconstructed quantitatively by the modern analogue technique were up to 1.3 °C higher for MIS 5e, MIS 5d and MIS 5b, possibly reflecting weaker modern vegetation analogues for these intervals.

A novel gene, MdSSK1, as a component of the SCF complex rather than MdSBP1 can mediate the ubiquitination of S-RNase in apple.

PubMed

Yuan, Hui; Meng, Dong; Gu, Zhaoyu; Li, Wei; Wang, Aide; Yang, Qing; Zhu, Yuandi; Li, Tianzhong

2014-07-01

As a core factor in S-RNase-based gametophytic self-incompatibility (GSI), the SCF (SKP1-Cullin1-F-box-Rbx1) complex (including pollen determinant SLF, S-locus-F-box) functions as an E3 ubiquitin ligase on non-self S-RNase. The SCF complex is formed by SKP1 bridging between SLF, CUL1, and Rbx1; however, it is not known whether an SCF complex lacking SKP1 can mediate the ubiquitination of S-RNase. Three SKP1-like genes from pollen were cloned based on the structural features of the SLF-interacting-SKP1-like (SSK) gene and the 'Golden Delicious' apple genome. These genes have a motif of five amino acids following the standard 'WAFE' at the C terminal and, in addition, contain eight sheets and two helices. All three genes were expressed exclusively in pollen. In the yeast two-hybrid and pull-down assays only one was found to interact with MdSFBB and MdCUL1, suggesting it is the SLF-interacting SKP1-like gene in apple which was named MdSSK1. In vitro experiments using MdSSK1, S2-MdSFBB1 (S2-Malus domestica S-locus-F-box brother) and MdCUL1 proteins incubated with S 2-RNase and ubiquitin revealed that the SCF complex ubiquitinylates S-RNase in vitro, while MdSBP1 (Malus domestica S-RNase binding protein 1) could not functionally replace MdSSK1 in the SCF complex in ubiquitinylating S-RNase. According to the above experiments, MdSBP1 is probably the only factor responsible for recognition with S-RNase, while not a component of the SCF complex, and an SCF complex containing MdSSK1 is required for mediating the ubiquitination of S-RNase. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Sensitivity to tomato and peanut allergens in children monosensitized to grass pollen.

PubMed

de Martino, M; Novembre, E; Cozza, G; de Marco, A; Bonazza, P; Vierucci, A

1988-04-01

Possible associations between allergy to grass pollen and positive skin tests to food allergens were studied in 102 children monosensitized (as to inhalant allergens) to grass pollen, and in 117 children monosensitized (as to inhalant allergens) to Dermatophagoides. Thirty-two foods were tested by an epicutaneous method. Positive skin tests to food allergens were more frequent in children with allergy to grass pollen (59.8%) than in children with allergy to Dermatophagoides (9.4%). A considerably high frequency of positive reactions to tomato (39.2%), peanut (22,5%), green pea (13.7%), and wheat (11.7%) was observed in children with allergy to grass pollen. Positive skin tests to peanut closely correlated with positive RAST results and nasal provocation tests, whereas in children with skin test positivity to tomato a close correlation with nasal provocation tests but a 45% correlation with a positive RAST result were observed. RAST inhibition experiments were carried out, and the results may suggest the presence of cross-reacting IgE to grass pollen, tomato, and peanut antigens. Clinical implications of these findings are discussed in the light of histories of food hypersensitivity, urticaria-angioedema, and atopic dermatitis in children with allergy to grass pollen.

How common is self-incompatibility across species of the herkogamous genus Ariocarpus?

PubMed

Martínez-Peralta, Concepción; Márquez-Guzmán, Judith; Mandujano, María C

2014-03-01

Self-incompatibility (SI), the most effective mechanism to prevent selfing, may limit the number of compatible mates in populations. The seven species of Ariocarpus are endangered and predominantly outcrossers but fruit set may reach 1-20% after selfing. We aimed to determine whether SI is the underlying mechanism influencing mating in Ariocarpus species. We characterized the presence/absence of SI using pollination treatments (self-pollination, cross-pollination, natural pollination) in one population per species. We assessed SI using epifluorescence and generalized linear models (GLMs) to compare the presence of pollen tubes in the stigma, stylar transmitting tissue, and ovary among self- and cross-pollinated pistils 48 h after pollination. Following the same treatments, production of fruit set was noted and related to pollen tube growth. Pollen tubes were found more frequently in the ovaries of natural and cross-pollinated flowers than in ovaries of self-pollinated. Stylar rejection of self-pollen indicated gametophytic SI, although pollen tubes reached the ovaries in six species (4-33% of pistils). Fruit set was lower after hand-pollinations than expected from pollen tube observations. The low percentages of self-compatibility in all species in pollen tube growth and pollination experiments indicated that no species had complete self-sterility, suggesting the presence of partial SI. Reduced fruit set relative to pollen tube production could result from a threshold of insufficient pollination, early-acting inbreeding depression, or resource limitation. The origin of partial SI in Ariocarpus could respond to pressures such as pollen limitation and population size.

Pollen mitosis and pollen tube growth inhibition by SO/sub 2/ in cultured pollen tubes of Tradescantia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, T.H.; Khan, S.H.

Mature pollen of Tradescantia paludosa Anders, Sax clone-3 was collected from greenhouse grown plants and desiccated in the dark for 4--5 hours. The pollen was sown on microslides coated with lactose agar medium (supplemented with 0.02 percent colchicine). Five minutes after sowing, pollen cultures were treated with various concentrations (0.075--2000 ppM) of SO/sub 2/ obtained from the chemical reaction between K/sub 2/S/sub 2/O/sub 5/ and HCl. Treatments were carried out in an airtight Plexiglas chamber throughout the full incubation period of 19 hours. Treated and control pollen cultures were fixed and stained in aceto-carmine or Feulgen reaction to determine themore » tube lengths and mitotic indices. Results of repeated experiments indicated that the values of mitotic indices dropped from the normal 38.7 percent in the control to the range of 24.3--3.8 percent when treated with 0.075--50.00 ppM of SO/sub 2/. Pollen tube growth was inhibited from the normal length of 1.5 mm in the control to the range of 800--100 ..mu..m when treated with 10--2000 ppM of SO/sub 2/. The inhibitory effect of SO/sub 2/ presumably resulted from physiological disturbance of the cell and severe damage to chromosomes of both generative and tube nuclei of the pollen tubes.« less

Identification and expression analysis of BoMF25, a novel polygalacturonase gene involved in pollen development of Brassica oleracea.

PubMed

Lyu, Meiling; Liang, Ying; Yu, Youjian; Ma, Zhiming; Song, Limin; Yue, Xiaoyan; Cao, Jiashu

2015-06-01

BoMF25 acts on pollen wall. Polygalacturonase (PG) is a pectin-digesting enzyme involved in numerous plant developmental processes and is described to be of critical importance for pollen wall development. In the present study, a PG gene, BoMF25, was isolated from Brassica oleracea. BoMF25 is the homologous gene of At4g35670, a PG gene in Arabidopsis thaliana with a high expression level at the tricellular pollen stage. Collinear analysis revealed that the orthologous gene of BoMF25 in Brassica campestris (syn. B. rapa) genome was probably lost because of genome deletion and reshuffling. Sequence analysis indicated that BoMF25 contained four classical conserved domains (I, II, III, and IV) of PG protein. Homology and phylogenetic analyses showed that BoMF25 was clustered in Clade F. The putative promoter sequence, containing classical cis-acting elements and pollen-specific motifs, could drive green fluorescence protein expression in onion epidermal cells. Quantitative RT-PCR analysis suggested that BoMF25 was mainly expressed in the anther at the late stage of pollen development. In situ hybridization analysis also indicated that the strong and specific expression signal of BoMF25 existed in pollen grains at the mature pollen stage. Subcellular localization showed that the fluorescence signal was observed in the cell wall of onion epidermal cells, which suggested that BoMF25 may be a secreted protein localized in the pollen wall.

Clinical and immunobiochemical characterization of airborne Delonix regia (Gulmohar tree) pollen and cross-reactivity studies with Peltophorum pterocarpum pollen: 2 dominant avenue trees from eastern India.

PubMed

Mandal, Jyotshna; Manna, Prasenjit; Chakraborty, Pampa; Roy, Indrani; Gupta-Bhattacharya, Swati

2009-12-01

Delonix regia and Peltophorum pterocarpum pollen are important aeroallergens for type 1 hypersensitivity in the tropics. The IgE-binding proteins of D regia and their cross-allergenity with P pterocarpum pollen have not been evaluated. To isolate and characterize the IgE-binding proteins of D regia pollen for the first time and to investigate the cross-allergenity with P pterocarpum pollen belonging to the same family (Leguminosae). Allergenic activities were determined by in vivo and in vitro analyses. Pollen extract was fractionated by a combination of 2 columns (diethyl amino ethyl Sephadex and Sephacryl S-200). Protein components were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, periodic acid-Schiff staining, and immunoblotting. In vitro inhibition tests were performed to evaluate the cross-reactivity. The skin prick test results of the patients with respiratory allergies in Calcutta, India, showed 31.1% positivity with D regia pollen. Nine IgE-reactive protein components were found in the crude extract. An optimum IgE-reactive fraction was resolved into 4 subfractions. Subfraction A, which showed maximum IgE reactivity, contained 2 (96- and 66-kDa) IgE-reactive protein components. The 66-kDa component was found to be glycoprotein. Remarkable cross-reactivity between D regia and P pterocarpum pollen was found on IgE enzyme-linked immunosorbent assay inhibition and dot blotting. Shared IgE-binding components (66, 56, 32, 28, 25, and 23 kDa) were observed between D regia and P pterocarpum pollen extracts, whereas the 96- and 43-kDa components were specific to D regia. The purification of the IgE-binding proteins and the identification of the shared/cross-reactive proteins in these taxonomically related pollen members should be helpful for the diagnosis and therapy of patients susceptible to these pollens.

Defective Pollen Wall is Required for Anther and Microspore Development in Rice and Encodes a Fatty Acyl Carrier Protein Reductase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, J.; Shanklin, J.; Tan, H.

Aliphatic alcohols naturally exist in many organisms as important cellular components; however, their roles in extracellular polymer biosynthesis are poorly defined. We report here the isolation and characterization of a rice (Oryza sativa) male-sterile mutant, defective pollen wall (dpw), which displays defective anther development and degenerated pollen grains with an irregular exine. Chemical analysis revealed that dpw anthers had a dramatic reduction in cutin monomers and an altered composition of cuticular wax, as well as soluble fatty acids and alcohols. Using map-based cloning, we identified the DPW gene, which is expressed in both tapetal cells and microspores during anther development.more » Biochemical analysis of the recombinant DPW enzyme shows that it is a novel fatty acid reductase that produces 1-hexadecanol and exhibits >270-fold higher specificity for palmiltoyl-acyl carrier protein than for C16:0 CoA substrates. DPW was predominantly targeted to plastids mediated by its N-terminal transit peptide. Moreover, we demonstrate that the monocot DPW from rice complements the dicot Arabidopsis thaliana male sterile2 (ms2) mutant and is the probable ortholog of MS2. These data suggest that DPWs participate in a conserved step in primary fatty alcohol synthesis for anther cuticle and pollen sporopollenin biosynthesis in monocots and dicots.« less

Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pumpkin (Cucurbita pepo) agroecosystems

PubMed Central

Phillips, Benjamin W.

2015-01-01

Pumpkin (Cucurbita pepo) production relies on insect-mediated pollination, which is provided by managed and wild pollinators. The goals of this study were to measure the visitation frequency, longevity and temporal activity patterns of pumpkin pollinators and to determine if local habitat management and landscape composition affected this pollination service. We used video surveillance to monitor bee acitivty within male and female pumpkin flowers in 2011 and 2012 across a pollination window of 0600–1200 h. We also quantified the amount of pollen deposited in female flowers across this time period. In 2011, A. mellifera made significantly more floral visits than other bees, and in 2012 Bombus spp. was the dominant pumpkin pollinator. We found variation in visitation among male and female pumpkin flowers, with A. mellifera visiting female flowers more often and spending longer per visit within them than male flowers in both 2011 and 2012. The squash bee P. pruinosa visited male flowers more frequently in 2012, but individuals spent equal time in both flower sexes. We did not find variation in the timing of flower visitation among species across the observed pollination window. In both 2011 and 2012 we found that the majority of pollen deposition occurred within the first two hours (0600–0800 h) of observation; there was no difference between the pollen deposited during this two-hour period and full pollination window (0600–1200 h). Local additions of sweet alyssum floral strips or a field buffer strip of native wildflowers did not have an effect on the foraging activity of bees or pollen deposition. However, semi-natural and urban habitats in the surrounding landscape were positively correlated with the frequency of flower visitation by wild pollinators and the amount of pollen deposited within female flowers. PMID:26587337

Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pumpkin (Cucurbita pepo) agroecosystems.

PubMed

Phillips, Benjamin W; Gardiner, Mary M

2015-01-01

Pumpkin (Cucurbita pepo) production relies on insect-mediated pollination, which is provided by managed and wild pollinators. The goals of this study were to measure the visitation frequency, longevity and temporal activity patterns of pumpkin pollinators and to determine if local habitat management and landscape composition affected this pollination service. We used video surveillance to monitor bee acitivty within male and female pumpkin flowers in 2011 and 2012 across a pollination window of 0600-1200 h. We also quantified the amount of pollen deposited in female flowers across this time period. In 2011, A. mellifera made significantly more floral visits than other bees, and in 2012 Bombus spp. was the dominant pumpkin pollinator. We found variation in visitation among male and female pumpkin flowers, with A. mellifera visiting female flowers more often and spending longer per visit within them than male flowers in both 2011 and 2012. The squash bee P. pruinosa visited male flowers more frequently in 2012, but individuals spent equal time in both flower sexes. We did not find variation in the timing of flower visitation among species across the observed pollination window. In both 2011 and 2012 we found that the majority of pollen deposition occurred within the first two hours (0600-0800 h) of observation; there was no difference between the pollen deposited during this two-hour period and full pollination window (0600-1200 h). Local additions of sweet alyssum floral strips or a field buffer strip of native wildflowers did not have an effect on the foraging activity of bees or pollen deposition. However, semi-natural and urban habitats in the surrounding landscape were positively correlated with the frequency of flower visitation by wild pollinators and the amount of pollen deposited within female flowers.

Pollen-mediated gene flow and fine-scale spatial genetic structure in Olea europaea subsp. europaea var. sylvestris

PubMed Central

Piotti, A.; Satovic, Z.; de la Rosa, R.; Belaj, A.

2017-01-01

Abstract Background and Aims Wild olive (Olea europaea subsp. europaea var. sylvestris) is important from an economic and ecological point of view. The effects of anthropogenic activities may lead to the genetic erosion of its genetic patrimony, which has high value for breeding programmes. In particular, the consequences of the introgression from cultivated stands are strongly dependent on the extent of gene flow and therefore this work aims at quantitatively describing contemporary gene flow patterns in wild olive natural populations. Methods The studied wild population is located in an undisturbed forest, in southern Spain, considered one of the few extant hotspots of true oleaster diversity. A total of 225 potential father trees and seeds issued from five mother trees were genotyped by eight microsatellite markers. Levels of contemporary pollen flow, in terms of both pollen immigration rates and within-population dynamics, were measured through paternity analyses. Moreover, the extent of fine-scale spatial genetic structure (SGS) was studied to assess the relative importance of seed and pollen dispersal in shaping the spatial distribution of genetic variation. Key Results The results showed that the population under study is characterized by a high genetic diversity, a relatively high pollen immigration rate (0·57), an average within-population pollen dispersal of about 107 m and weak but significant SGS up to 40 m. The population is a mosaic of several intermingled genetic clusters that is likely to be generated by spatially restricted seed dispersal. Moreover, wild oleasters were found to be self-incompatible and preferential mating between some genotypes was revealed. Conclusions Knowledge of the within-population genetic structure and gene flow dynamics will lead to identifying possible strategies aimed at limiting the effect of anthropogenic activities and improving breeding programmes for the conservation of olive tree forest genetic resources. PMID:28028015

Pollen-mediated gene flow and fine-scale spatial genetic structure in Olea europaea subsp. europaea var. sylvestris.

PubMed

Beghè, D; Piotti, A; Satovic, Z; de la Rosa, R; Belaj, A

2017-03-01

Wild olive ( Olea europaea subsp. europaea var. sylvestris ) is important from an economic and ecological point of view. The effects of anthropogenic activities may lead to the genetic erosion of its genetic patrimony, which has high value for breeding programmes. In particular, the consequences of the introgression from cultivated stands are strongly dependent on the extent of gene flow and therefore this work aims at quantitatively describing contemporary gene flow patterns in wild olive natural populations. The studied wild population is located in an undisturbed forest, in southern Spain, considered one of the few extant hotspots of true oleaster diversity. A total of 225 potential father trees and seeds issued from five mother trees were genotyped by eight microsatellite markers. Levels of contemporary pollen flow, in terms of both pollen immigration rates and within-population dynamics, were measured through paternity analyses. Moreover, the extent of fine-scale spatial genetic structure (SGS) was studied to assess the relative importance of seed and pollen dispersal in shaping the spatial distribution of genetic variation. The results showed that the population under study is characterized by a high genetic diversity, a relatively high pollen immigration rate (0·57), an average within-population pollen dispersal of about 107 m and weak but significant SGS up to 40 m. The population is a mosaic of several intermingled genetic clusters that is likely to be generated by spatially restricted seed dispersal. Moreover, wild oleasters were found to be self-incompatible and preferential mating between some genotypes was revealed. Knowledge of the within-population genetic structure and gene flow dynamics will lead to identifying possible strategies aimed at limiting the effect of anthropogenic activities and improving breeding programmes for the conservation of olive tree forest genetic resources. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

[Pollen vigor and development of germplasm of Dendrobium officinale].

PubMed

Zhu, Bo; Yuan, He; Yu, Qiaoxian; Si, Jinping

2011-03-01

To provide the theoretical basis and applied technology for breeding superior species of Dendrobium officinale. The peroxidase solution was used to test the pollen vigor in different flowering time and storage conditions. Cross, self and opening pollination were conducted in the green house, the subsidiary pollination by insects was carried out outdoors. The pollen of D. officinale was still in vigor when the flower faded. The pollen vigor was only 29.4% in the buds, 70.6% in the bloom day, and decreased to 31.9% a week later, it remained still 21.2% 20 days later under the condition of dry and 4 degrees C. The fructification rate was about 82.6% and 7.3%, respectively, when the cross and self pollination performed by hand in the whole flowering time, the rate was 0 in the green house and outdoors. The pollen of D. officinale was still in vigor during the whole flowering time, the fructification rate was 0 in the green house and outdoors resulted from the specific structure of flower. The wild resources of D. officinale were protected and germplasm was developed effectively through the artificial cross pollination.

Efficacy and safety of 4 months of sublingual immunotherapy with recombinant Mal d 1 and Bet v 1 in patients with birch pollen-related apple allergy.

PubMed

Kinaciyan, Tamar; Nagl, Birgit; Faustmann, Sandra; Frommlet, Florian; Kopp, Stephan; Wolkersdorfer, Martin; Wöhrl, Stefan; Bastl, Katharina; Huber, Hans; Berger, Uwe; Bohle, Barbara

2018-03-01

Birch pollen-related apple allergy is among the most prevalent food allergies in adolescent/adult subjects and mainly results from sensitization to the major birch pollen allergen Bet v 1 and subsequent cross-reaction with the apple protein Mal d 1. However, specific immunotherapy with birch pollen has inconsistent effects on apple allergy. We sought to compare the safety and efficacy of sublingual immunotherapy (SLIT) with 2 formulations containing either rMal d 1 or rBet v 1 on birch pollen-related apple allergy. Sixty participants with birch pollen-related apple allergy were randomized to daily sublingual application of placebo (n = 20) or 25 μg of rMal d 1 (n = 20) or rBet v 1 (n = 20) for 16 weeks. Adverse events were regularly recorded. Sublingual challenges with standardized doses of rMal d 1, skin prick tests with recombinant allergens, and measurements of allergen-specific IgE and IgG 4 antibodies were performed before and after treatment. Both formulations caused comparable, mainly local adverse events. No systemic reactions occurred. Compared with the placebo and rBet v 1-treated groups, SLIT with rMal d 1 reduced rMal d 1-induced oral symptoms (P = .001 and P = .038) accompanied by longitudinally reduced rMal d 1-specific cutaneous reactions (P = .022) and enhanced IgG 4 /IgE ratios (P = .012). SLIT with rBet v 1 neither improved the clinical reactivity to rMal d 1 nor enhanced rMal d 1-specific IgG 4 /IgE ratios. Participants receiving placebo showed no allergen-specific changes. Sublingual treatment with a recombinant food allergen was safe and clinically effective, as determined by using standardized challenges. We present a promising approach for the effective treatment of birch pollen-related apple allergy. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Assessment of real-time PCR based methods for quantification of pollen-mediated gene flow from GM to conventional maize in a field study.

PubMed

Pla, Maria; La Paz, José-Luis; Peñas, Gisela; García, Nora; Palaudelmàs, Montserrat; Esteve, Teresa; Messeguer, Joaquima; Melé, Enric

2006-04-01

Maize is one of the main crops worldwide and an increasing number of genetically modified (GM) maize varieties are cultivated and commercialized in many countries in parallel to conventional crops. Given the labeling rules established e.g. in the European Union and the necessary coexistence between GM and non-GM crops, it is important to determine the extent of pollen dissemination from transgenic maize to other cultivars under field conditions. The most widely used methods for quantitative detection of GMO are based on real-time PCR, which implies the results are expressed in genome percentages (in contrast to seed or grain percentages). Our objective was to assess the accuracy of real-time PCR based assays to accurately quantify the contents of transgenic grains in non-GM fields in comparison with the real cross-fertilization rate as determined by phenotypical analysis. We performed this study in a region where both GM and conventional maize are normally cultivated and used the predominant transgenic maize Mon810 in combination with a conventional maize variety which displays the characteristic of white grains (therefore allowing cross-pollination quantification as percentage of yellow grains). Our results indicated an excellent correlation between real-time PCR results and number of cross-fertilized grains at Mon810 levels of 0.1-10%. In contrast, Mon810 percentage estimated by weight of grains produced less accurate results. Finally, we present and discuss the pattern of pollen-mediated gene flow from GM to conventional maize in an example case under field conditions.

Tackling Bet v 1 and associated food allergies with a single hybrid protein.

PubMed

Hofer, Heidi; Asam, Claudia; Hauser, Michael; Nagl, Birgit; Laimer, Josef; Himly, Martin; Briza, Peter; Ebner, Christof; Lang, Roland; Hawranek, Thomas; Bohle, Barbara; Lackner, Peter; Ferreira, Fátima; Wallner, Michael

2017-08-01

Allergy vaccines should be easily applicable, safe, and efficacious. For Bet v 1-mediated birch pollen and associated food allergies, a single wild-type allergen does not provide a complete solution. We aimed to combine immunologically relevant epitopes of Bet v 1 and the 2 clinically most important related food allergens from apple and hazelnut to a single hybrid protein, termed MBC4. After identification of T cell epitope-containing parts on each of the 3 parental allergens, the hybrid molecule was designed to cover relevant epitopes and evaluated in silico. Thereby a mutation was introduced into the hybrid sequence, which should alter the secondary structure without compromising the immunogenic properties of the molecule. MBC4 and the parental allergens were purified to homogeneity. Analyses of secondary structure elements revealed substantial changes rendering the hybrid de facto nonreactive with patients' serum IgE. Nevertheless, the protein was monomeric in solution. MBC4 was able to activate T-cell lines from donors with birch pollen allergy and from mice immunized with the parental allergens. Moreover, on immunization of mice and rabbits, MBC4 induced cross-reactive IgG antibodies, which were able to block the binding of human serum IgE. Directed epitope rearrangements combined with a knowledge-based structural modification resulted in a protein unable to bind IgE from allergic patients. Still, properties to activate specific T cells or induce blocking antibodies were conserved. This suggests that MBC4 is a suitable vaccine candidate for the simultaneous treatment of Bet v 1 and associated food allergies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Effector cell signature in peripheral blood following nasal allergen challenge in grass pollen allergic individuals.

PubMed

Shamji, M H; Bellido, V; Scadding, G W; Layhadi, J A; Cheung, D K M; Calderon, M A; Asare, A; Gao, Z; Turka, L A; Tchao, N; Togias, A; Phippard, D; Durham, S R

2015-02-01

Several studies have demonstrated the time course of inflammatory mediators in nasal fluids following nasal allergen challenge (NAC), whereas the effects of NAC on cells in the periphery are unknown. We examined the time course of effector cell markers (for basophils, dendritic cells and T cells) in peripheral blood after nasal grass pollen allergen challenge. Twelve participants with seasonal allergic rhinitis underwent a control (diluent) challenge followed by NAC after an interval of 14 days. Nasal symptoms and peak nasal inspiratory flow (PNIF) were recorded along with peripheral basophil, T-cell and dendritic cell responses (flow cytometry), T-cell proliferative responses (thymidine incorporation), and cytokine expression (FluoroSpot assay). Robust increases in nasal symptoms and decreases in PNIF were observed during the early (0-1 h) response and modest significant changes during the late (1-24 h) response. Sequential peaks in peripheral blood basophil activation markers were observed (CD107a at 3 h, CD63 at 6 h, and CD203c(bright) at 24 h). T effector/memory cells (CD4(+) CD25(lo) ) were increased at 6 h and accompanied by increases in CD80(+) and CD86(+) plasmacytoid dendritic cells (pDCs). Ex vivo grass antigen-driven T-cell proliferative responses and the frequency of IL-4(+) CD4(+) T cells were significantly increased at 6 h after NAC when compared to the control day. Basophil, T-cell, and dendritic cell activation increased the frequency of allergen-driven IL-4(+) CD4(+) T cells, and T-cell proliferative responses are detectable in the periphery after NAC. These data confirm systemic cellular activation following a local nasal provocation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of acidity on tree Pollen germination and tube growth. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Ryn, D.M.; Jacobson, J.S.

Most of the northeastern hardwood forests in North America are exposed repeatedly to acidic rainfall at pH values below 5.0. Pollen germination, tube growth and fertilization, important parts of the reproductive process, are sensitive to changes in their chemical environment. Accordingly, the authors investigated the effects of acidity on pollen germination and tube elongation of four northeastern tree species: flowering dogwood, black birch, yellow birch, and sugar maple. Pollen was collected and germinated in a growth medium acidified to pH values ranging from 5.0 to 2.6. Pollen was found to be sensitive to acidification of the germination medium to belowmore » pH 4.2. These results suggest that acidic rain that now occurs in eastern North America may influence reproductive processes that are necessary for seed set and regeneration in northern hardwood forests.« less

Bee Pollen Improves Muscle Protein and Energy Metabolism in Malnourished Old Rats through Interfering with the Mtor Signaling Pathway and Mitochondrial Activity

PubMed Central

Salles, Jérôme; Cardinault, Nicolas; Patrac, Véronique; Berry, Alexandre; Giraudet, Christophe; Collin, Marie-Laure; Chanet, Audrey; Tagliaferri, Camille; Denis, Philippe; Pouyet, Corinne; Boirie, Yves; Walrand, Stéphane

2014-01-01

Although the management of malnutrition is a priority in older people, this population shows a resistance to refeeding. Fresh bee pollen contains nutritional substances of interest for malnourished people. The aim was to evaluate the effect of fresh bee pollen supplementation on refeeding efficiency in old malnourished rats. Male 22-month-old Wistar rats were undernourished by reducing food intake for 12 weeks. The animals were then renourished for three weeks with the same diet supplemented with 0%, 5% or 10% of fresh monofloral bee pollen. Due to changes in both lean mass and fat mass, body weight decreased during malnutrition and increased after refeeding with no between-group differences (p < 0.0001). Rats refed with the fresh bee pollen-enriched diets showed a significant increase in muscle mass compared to restricted rats (p < 0.05). The malnutrition period reduced the muscle protein synthesis rate and mTOR/p70S6kinase/4eBP1 activation, and only the 10%-pollen diet was able to restore these parameters. Mitochondrial activity was depressed with food restriction and was only improved by refeeding with the fresh bee pollen-containing diets. In conclusion, refeeding diets that contain fresh monofloral bee pollen improve muscle mass and metabolism in old, undernourished rats. PMID:25470375

Pollen Analysis of Natural Honeys from the Central Region of Shanxi, North China

PubMed Central

Song, Xiao-Yan; Yao, Yi-Feng; Yang, Wu-De

2012-01-01

Based on qualitative and quantitative melissopalynological analyses, 19 Chinese honeys were classified by botanical origin to determine their floral sources. The honey samples were collected during 2010–2011 from the central region of Shanxi Province, North China. A diverse spectrum of 61 pollen types from 37 families was identified. Fourteen samples were classified as unifloral, whereas the remaining samples were multifloral. Bee-favoured families (occurring in more than 50% of the samples) included Caprifoliaceae (found in 10 samples), Laminaceae (10), Brassicaceae (12), Rosaceae (12), Moraceae (13), Rhamnaceae (15), Asteraceae (17), and Fabaceae (19). In the unifloral honeys, the predominant pollen types were Ziziphus jujuba (in 5 samples), Robinia pseudoacacia (3), Vitex negundo var. heterophylla (2), Sophora japonica (1), Ailanthus altissima (1), Asteraceae type (1), and Fabaceae type (1). The absolute pollen count (i.e., the number of pollen grains per 10 g honey sample) suggested that 13 samples belonged to Group I (<20,000 pollen grains), 4 to Group II (20,000–100,000), and 2 to Group III (100,000–500,000). The dominance of unifloral honeys without toxic pollen grains and the low value of the HDE/P ratio (i.e., honey dew elements/pollen grains from nectariferous plants) indicated that the honey samples are of good quality and suitable for human consumption. PMID:23185358

Clinical and immunologic evaluation of Cedrus deodara pollen: a new allergen from India.

PubMed

Rawat, A; Singh, A; Singh, A B; Gaur, S N; Kumar, L; Roy, I; Ravindrun, P

2000-07-01

Allergy to pollen from gymnosperms is well documented in the West. However, many allergenic species are native to the Himalayan region of India, and Cedrus deodara (Pinaceae) was selected for allergologic investigation. The objective was to define the allergologic and immunochemical aspects of C. deodara pollen. Pollen antigen from C. deodara (CD) was prepared and characterized by biochemical and biologic assays. Specific IgE binding was determined by means of ELISA and immunoblotting. CD pollen antigen caused marked skin sensitivity in 7.5% of an atopic population. A significantly elevated level of CD-specific IgE antibodies was observed in 65.8% of the skin-positive patients. Immunoblotting showed protein fractions of 37, 44, 58, and 78 kDa with 100% binding with the patients' sera suspected to be due to carbohydrate moieties. Patients from the Himalayan region, where CD occurs naturally, were sensitized more than patients from distant places. The immunochemical characterization revealed multiple protein fractions from low to very high molecular mass (14-126 kDa) mostly in the acidic pI range. CD pollen has been recognized as a new allergen from India for the first time. The role of pollen as a causative agent of respiratory allergic disorders is very well established, as is evident from the recent increase of reports from across the world (1-4). India is blessed with the richest flora on the earth, from alpine tundra to Rajasthan desert. Consequently, it provides considerable variation in the quality and quantity of airborne pollen in different ecogeographic regions of the country (5-8). Although studies on the allergenic properties of airborne pollen from various species have been carried out by several workers in India (9-12), information on allergy to aerial pollen from Himalayan tree species has been completely

Marine palynological record for tropical climate variations since the late last glacial maximum in the northern South China Sea

NASA Astrophysics Data System (ADS)

Dai, Lu; Weng, Chengyu

2015-12-01

The upper part (191-1439 cm) of the marine sediment core MD05-2906 from the northern South China Sea (SCS) was palynologically investigated. The chronology suggested that it covered the record since ~19 calendar kiloyears before present (cal ka BP) and revealed a detailed environmental change history since the late last glacial maximum (LGM). During the late LGM, due to the lowered sea level (~100 m lower) and the shortened distance from the shore to the study site, the pollen concentration was very high. The pollen assemblages were dominated by non-arboreal taxa, especially Artemisia pollen, before ~15 cal ka BP. Abundant subtropical and tropical pollen taxa were still important components and a south subtropical climate prevailed during the late LGM. The coexistent rich Artemisia pollen possibly was not derived from near shores, but was derived mainly from the northern exposed continental shelf in the East China Sea (ECS). After ~15 cal ka BP, with the rise in the sea level and enhanced distance from the pollen source areas to the core site, pollen concentrations started to decline gradually. However, during the late deglaciation and early Holocene, the higher concentrations of many pollen taxa reoccurred, which cannot be attributed to the sea level changes. Pinus pollen deposited in the core, which is considered to be mostly water-carried based on many modern pollen surveys, also started to dramatically increase at the same time. Therefore, the higher pollen concentration, with more Pinus and Typha (an aquatic plant) pollen indicated a notably enhanced terrestrial runoff and precipitation during the last deglaciation/Holocene transition (~11.3-9.4 cal ka BP). We inferred that a strong summer monsoon occurred at this time. During the late LGM/deglaciation transition period, the pollen assemblage reflected a gradually warming climate, and the climate fluctuations derived from the high-latitudes were not well-identified. This study suggests that solar insolation played a crucial role in controlling the East Asian monsoon and hydrological cycle in the northern SCS.

Influence of rain on the abundance of bioaerosols in fine and coarse particles

NASA Astrophysics Data System (ADS)

Rathnayake, Chathurika M.; Metwali, Nervana; Jayarathne, Thilina; Kettler, Josh; Huang, Yuefan; Thorne, Peter S.; O'Shaughnessy, Patrick T.; Stone, Elizabeth A.

2017-02-01

Assessing the environmental, health, and climate impacts of bioaerosols requires knowledge of their size and abundance. These two properties were assessed through daily measurements of chemical tracers for pollens (sucrose, fructose, and glucose), fungal spores (mannitol and glucans), and Gram-negative bacterial endotoxins in two particulate matter (PM) size modes: fine particles (< 2.5 µm) and coarse particles (2.5-10 µm) as determined by their aerodynamic diameter. Measurements were made during the spring tree pollen season (mid-April to early May) and late summer ragweed season (late August to early September) in the Midwestern US in 2013. Under dry conditions, pollen, and fungal spore tracers were primarily in coarse PM (> 75 %), as expected for particles greater than 2.5 µm. Rainfall on 2 May corresponded to maximum atmospheric pollen tracer levels and a redistribution of pollen tracers to the fine PM fraction (> 80 %). Both changes were attributed to the osmotic rupture of pollen grains that led to the suspension of fine-sized pollen fragments. Fungal spore tracers peaked in concentration following spring rain events and decreased in particle size, but to a lesser extent than pollens. A short, heavy thunderstorm in late summer corresponded to an increase in endotoxin and glucose levels, with a simultaneous shift to smaller particle sizes. Simultaneous increase in bioaerosol levels and decrease in their size have significant implications for population exposures to bioaerosols, particularly during rain events. Chemical mass balance (CMB) source apportionment modeling and regionally specific pollen profiles were used to apportion PM mass to pollens and fungal spores. Springtime pollen contributions to the mass of particles < 10 µm (PM10) ranged from 0.04 to 0.8 µg m-3 (0.2-38 %, averaging 4 %), with maxima occurring on rainy days. Fungal spore contributions to PM10 mass ranged from 0.1 to 1.5 µg m-3 (0.8-17 %, averaging 5 %), with maxima occurring after rain. Overall, this study defines changes to the fine- and coarse-mode distribution of PM, pollens, fungal spores, and endotoxins in response to rain in the Midwestern United States and advances the ability to apportion PM mass to pollens.

Bee-mediated pollen transfer in two populations of Cypripedium montanum Douglas ex Lindley

Treesearch

Peter Bernhardt; Retha Edens-Meier; Eric Westhus; Nan Vance

2014-01-01

The conversion rate of flowers into fruit in C. montanum at two sites over four seasons was 52-85%, unusually high for a food mimic orchid. Comparative measurements of the trap-like labellum of C. montanum showed it was intermediate in size compared to measurements of six other Cypripedium spp. found in...

Rf8-mediated T-urf13 transcript accumulation coincides with a pentatricopeptide repeat cluster on maize chromosome 2L

USDA-ARS?s Scientific Manuscript database

Cytoplasmic male sterility (CMS) is a maternally inherited inability to produce functional pollen. In T-cytoplasm maize, CMS results from the action of the URF13 mitochondrial pore-forming protein, encoded by the unique T-urf13 mitochondrial gene. Full or partial restoration of fertility to T-cyto...

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. I. Rush immunotherapy with allergoids and standardized orchard grass-pollen extract.

PubMed

Bousquet, J; Hejjaoui, A; Skassa-Brociek, W; Guérin, B; Maasch, H J; Dhivert, H; Michel, F B

1987-10-01

Forty-five grass pollen-allergic patients were randomly assigned to three groups according to their skin test and RAST sensitivities and the severity of seasonal rhinitis. Eleven patients were treated with placebo (group 1), 19 patients (group 2) were treated with a six-mixed grass-pollen allergoid prepared by mild formalinization with a two-step procedure, and 15 other patients were treated with a standardized orchard grass-pollen extract (group 3). Because of a different immunotherapy schedule, only patients placed in groups 1 and 2 received the extracts in a double-blind fashion. Rush immunotherapy was performed in 3 to 6 days, and the maintenance dose was subsequently administered weekly for 4 weeks and every 2 weeks until the end of the grass-pollen season. During the season, a coseasonal treatment was administered. Systemic reactions occurred during the rush protocol in 36.8% of patients treated with allergoid and 20% of patients who received the standardized extract. Only patients treated with allergoid had systemic reactions during maintenance dose. The reactions observed with the standardized extract were more severe. Total doses of allergoid ranged from 2350 to 13,500 protein nitrogen units. Symptoms and medication scores during the peak of the season were analyzed. Patients treated with the standardized allergen had a significant reduction of the number of days of symptoms during the month of June (9.5 +/- 6.7 days; p less than 0.005) and of medication scores (1.3 +/- 1.4; p less than 0.01) compared to patients receiving placebo (19.4 +/- 8.1 days; medication score, 2.8 +/- 2.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Genomic analysis of the interaction between pesticide exposure and nutrition in honey bees (Apis mellifera).

PubMed

Schmehl, Daniel R; Teal, Peter E A; Frazier, James L; Grozinger, Christina M

2014-12-01

Populations of pollinators are in decline worldwide. These declines are best documented in honey bees and are due to a combination of stressors. In particular, pesticides have been linked to decreased longevity and performance in honey bees; however, the molecular and physiological pathways mediating sensitivity and resistance to pesticides are not well characterized. We explored the impact of coumaphos and fluvalinate, the two most abundant and frequently detected pesticides in the hive, on genome-wide gene expression patterns of honey bee workers. We found significant changes in 1118 transcripts, including genes involved in detoxification, behavioral maturation, immunity, and nutrition. Since behavioral maturation is regulated by juvenile hormone III (JH), we examined effects of these miticides on hormone titers; while JH titers were unaffected, titers of methyl farnesoate (MF), the precursor to JH, were decreased. We further explored the association between nutrition- and pesticide-regulated gene expression patterns and demonstrated that bees fed a pollen-based diet exhibit reduced sensitivity to a third pesticide, chlorpyrifos. Finally, we demonstrated that expression levels of several of the putative pesticide detoxification genes identified in our study and previous studies are also upregulated in response to pollen feeding, suggesting that these pesticides and components in pollen modulate similar molecular response pathways. Our results demonstrate that pesticide exposure can substantially impact expression of genes involved in several core physiological pathways in honey bee workers. Additionally, there is substantial overlap in responses to pesticides and pollen-containing diets at the transcriptional level, and subsequent analyses demonstrated that pollen-based diets reduce workers' pesticide sensitivity. Thus, providing honey bees and other pollinators with high quality nutrition may improve resistance to pesticides. Copyright © 2014 Elsevier Ltd. All rights reserved.

Apple S-RNase interacts with an actin-binding protein, MdMVG, to reduce pollen tube growth by inhibiting its actin-severing activity at the early stage of self-pollination induction.

PubMed

Yang, Qing; Meng, Dong; Gu, Zhaoyu; Li, Wei; Chen, Qiuju; Li, Yang; Yuan, Hui; Yu, Jie; Liu, Chunsheng; Li, Tianzhong

2018-04-18

In S-RNase-mediated self-incompatibility, S-RNase secreted from the style destroys the actin cytoskeleton of the self-pollen tubes, eventually halting their growth, but the mechanism of this process remains unclear. In vitro biochemical assays revealed that S-RNase does not bind or sever filamentous actin (F-actin). In apple (Malus domestica), we identified an actin-binding protein containing myosin, villin and GRAM (MdMVG), that physically interacts with S-RNase and directly binds and severs F-actin. Immunofluorescence assays and total internal reflection fluorescence microscopy indicated that S-RNase inhibits the F-actin-severing activity of MdMVG in vitro. In vivo, the addition of S-RNase to self-pollen tubes increased the fluorescence intensity of actin microfilaments and reduced the severing frequency of microfilaments and the rate of pollen tube growth in self-pollination induction in the presence of MdMVG overexpression. By generating 25 single-, double- and triple-point mutations in the amino acid motif E-E-K-E-K of MdMVG via mutagenesis and testing the resulting mutants with immunofluorescence, we identified a triple-point mutant, MdMVG (E167A/E171A/K185A) , that no longer has F-actin-severing activity or interacts with any of the four S-haplotype S-RNases, indicating that all three amino acids (E167, E171 and K185) are essential for the severing activity of MdMVG and its interaction with S-RNases. We conclude that apple S-RNase interacts with MdMVG to reduce self-pollen tube growth by inhibiting its F-actin-severing activity. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Unilateral incompatibility gene ui1.1 encodes an S-locus F-box protein expressed in pollen of Solanum species.

PubMed

Li, Wentao; Chetelat, Roger T

2015-04-07

Unilateral interspecific incompatibility (UI) is a postpollination, prezygotic reproductive barrier that prevents hybridization between related species when the female parent is self-incompatible (SI) and the male parent is self-compatible (SC). In tomato and related Solanum species, two genes, ui1.1 and ui6.1, are required for pollen compatibility on pistils of SI species or hybrids. We previously showed that ui6.1 encodes a Cullin1 (CUL1) protein. Here we report that ui1.1 encodes an S-locus F-box (SLF) protein. The ui1.1 gene was mapped to a 0.43-cM, 43.2-Mbp interval at the S-locus on chromosome 1, but positional cloning was hampered by low recombination frequency. We hypothesized that ui1.1 encodes an SLF protein(s) that interacts with CUL1 and Skp1 proteins to form an SCF-type (Skp1, Cullin1, F-box) ubiquitin E3 ligase complex. We identified 23 SLF genes in the S. pennellii genome, of which 19 were also represented in cultivated tomato (S. lycopersicum). Data from recombination events, expression analysis, and sequence annotation highlighted 11 S. pennellii genes as candidates. Genetic transformations demonstrated that one of these, SpSLF-23, is sufficient for ui1.1 function. A survey of cultivated and wild tomato species identified SLF-23 orthologs in each of the SI species, but not in the SC species S. lycopersicum, S. cheesmaniae, and S. galapagense, pollen of which lacks ui1.1 function. These results demonstrate that pollen compatibility in UI is mediated by protein degradation through the ubiquitin-proteasome pathway, a mechanism related to that which controls pollen recognition in SI.

Patterns of among- and within-species variation in heterospecific pollen receipt: The importance of ecological generalization.

PubMed

Arceo-Gómez, Gerardo; Abdala-Roberts, Luis; Jankowiak, Anneka; Kohler, Clare; Meindl, George A; Navarro-Fernández, Carmen M; Parra-Tabla, Víctor; Ashman, Tia-Lynn; Alonso, Conchita

2016-03-01

Coflowering plants are at risk for receiving pollen from heterospecifics as well as conspecifics, yet evidence shows wide variation in the degree that heterospecific pollen transfer occurs. Evaluation of patterns and correlates of among- and within-species variation in heterospecific pollen (HP) receipt is key to understanding its importance for floral evolution and species coexistence; however, the rarity of deeply sampled multispecies comparisons has precluded such an evaluation. We evaluated patterns of among- and within-species variation in HP load size and diversity in 19 species across three distinct plant communities. We assessed the importance of phenotypic specialization (floral phenotype), ecological specialization (contemporary visitor assemblage), and conspecific flower density as determinants of among-species variation. We present hypotheses for different accrual patterns of HP within species based on the evenness and quality of floral visitors and evaluated these by characterizing the relationship between conspecific pollen (CP) and HP receipt. We found that within-species variation in HP receipt was greater than among-species and among-communities variation. Among species, ecological generalization emerged as the strongest driver of variation in HP receipt irrespective of phenotypic specialization. Within-species variation in HP load size and diversity was predicted most often from two CP-HP relationships (linear or exponentially decreasing), suggesting that two distinct types of plant-pollinator interactions prevail. Our results give important insights into the potential drivers of among- and within-species variation in HP receipt. They also highlight the value of explorations of patterns at the intraspecific level, which can ultimately shed light on plant-pollinator-mediated selection in diverse plant communities. © 2016 Botanical Society of America.

Therapeutic potency of bee pollen against biochemical autistic features induced through acute and sub-acute neurotoxicity of orally administered propionic acid.

PubMed

Al-Salem, Huda S; Bhat, Ramesa Shafi; Al-Ayadhi, Laila; El-Ansary, Afaf

2016-04-23

It is now well documented that postnatal exposure to certain chemicals has been reported to increase the risk of autism spectrum disorder. Propionic acid (PA), as a metabolic product of gut microbiotaandas a commonly used food additive, has been reported to mediate the effects of autism. Results from animal studies may help to identify environmental neurotoxic agents and drugs that can ameliorate neurotoxicity and may thereby aid in the treatment of autism. The present study investigated the ameliorative effects of natural bee pollen against acute and sub-acute brain intoxication induced by (PA) in rats. Twenty-four young male Western Albino ratswere enrolled in the present study. They were classified into four equal groups, eachwith6 rats. The control group received only phosphate buffered saline; the oral buffered PA-treated groups (II and III) received a neurotoxic dose of 750 mg/kg body weight divided in 3 dose of 250 mg/kg body weight/day serving asthe acute group and 750 mg/kg body weight divided in 10 equal dose of 75 mg/kg body weight/day as the sub-acute group. The fourth group received 50 mg bee pollen for 30 days after PA-acute intoxication. The obtained data showed that the PA-treated groups demonstrated multiple signs of brain toxicity, as indicated by a depletion of serotonin (5HT), dopamine and nor-adrenaline, together withan increase in IFN-γ and caspase 3. Bee pollen was effective in ameliorating the neurotoxic effect of PA. All measured parameters demonstrated minimal alteration in comparison with thecontrol animal than did those of acute and sub-acute PA-treated animals. In conclusion, bee pollen demonstrates anti-inflammatory and anti-apoptotic effects while ameliorating the impaired neurochemistry of PA-intoxicated rats.

Do specialized flowers promote reproductive isolation? Realized pollination accuracy of three sympatric Pedicularis species

PubMed Central

Armbruster, W. Scott; Shi, Xiao-Qing; Huang, Shuang-Quan

2014-01-01

Background and Aims Interest in pollinator-mediated evolutionary divergence of flower phenotype and speciation in plants has been at the core of plant evolutionary studies since Darwin. Specialized pollination is predicted to lead to reproductive isolation and promote speciation among sympatric species by promoting partitioning of (1) the species of pollinators used, (2) when pollinators are used, or (3) the sites of pollen placement. Here this last mechanism is investigated by observing the pollination accuracy of sympatric Pedicularis species (Orobanchacae). Methods Pollinator behaviour was observed on three species of Pedicularis (P. densispica, P. tricolor and P. dichotoma) in the Hengduan Mountains, south-west China. Using fluorescent powder and dyed pollen, the accuracy was assessed of stigma contact with, and pollen deposition on, pollinating bumble-bees, respectively. Key Results All three species of Pedicularis were pollinated by bumble-bees. It was found that the adaptive accuracy of female function was much higher than that of male function in all three flower species. Although peak pollen deposition corresponded to the optimal location on the pollinator (i.e. the site of stigma contact) for each species, substantial amounts of pollen were scattered over much of the bees' bodies. Conclusions The Pedicularis species studied in the eastern Himalayan region did not conform with Grant's ‘Pedicularis Model’ of mechanical reproductive isolation. The specialized flowers of this diverse group of plants seem unlikely to have increased the potential for reproductive isolation or influenced rates of speciation. It is suggested instead that the extreme species richness of the Pedicularis clade was generated in other ways and that specialized flowers and substantial pollination accuracy evolved as a response to selection generated by the diversity of co-occurring congeners. PMID:24047714

Plant villin, lily P-135-ABP, possesses G-actin binding activity and accelerates the polymerization and depolymerization of actin in a Ca2+-sensitive manner.

PubMed

Yokota, Etsuo; Tominaga, Motoki; Mabuchi, Issei; Tsuji, Yasunori; Staiger, Christopher J; Oiwa, Kazuhiro; Shimmen, Teruo

2005-10-01

From germinating pollen of lily, two types of villins, P-115-ABP and P-135-ABP, have been identified biochemically. Ca(2+)-CaM-dependent actin-filament binding and bundling activities have been demonstrated for both villins previously. Here, we examined the effects of lily villins on the polymerization and depolymerization of actin. P-115-ABP and P-135-ABP present in a crude protein extract prepared from germinating pollen bound to a DNase I affinity column in a Ca(2+)-dependent manner. Purified P-135-ABP reduced the lag period that precedes actin filament polymerization from monomers in the presence of either Ca(2+) or Ca(2+)-CaM. These results indicated that P-135-ABP can form a complex with G-actin in the presence of Ca(2+) and this complex acts as a nucleus for polymerization of actin filaments. However, the nucleation activity of P-135-ABP is probably not relevant in vivo because the assembly of G-actin saturated with profilin, a situation that mimics conditions found in pollen, was not accelerated in the presence of P-135-ABP. P-135-ABP also enhanced the depolymerization of actin filaments during dilution-mediated disassembly. Growth from filament barbed ends in the presence of Ca(2+)-CaM was also prevented, consistent with filament capping activity. These results suggested that lily villin is involved not only in the arrangement of actin filaments into bundles in the basal and shank region of the pollen tube, but also in regulating and modulating actin dynamics through its capping and depolymerization (or fragmentation) activities in the apical region of the pollen tube, where there is a relatively high concentration of Ca(2+).

Quantifying Aerial Concentrations of Maize Pollen in the Atmospheric Surface Layer Using Remote-Piloted Airplanes and Lagrangian Stochastic Modeling

NASA Astrophysics Data System (ADS)

Aylor, Donald E.; Boehm, Matthew T.; Shields, Elson J.

2006-07-01

The extensive adoption of genetically modified crops has led to a need to understand better the dispersal of pollen in the atmosphere because of the potential for unwanted movement of genetic traits via pollen flow in the environment. The aerial dispersal of maize pollen was studied by comparing the results of a Lagrangian stochastic (LS) model with pollen concentration measurements made over cornfields using a combination of tower-based rotorod samplers and airborne radio-controlled remote-piloted vehicles (RPVs) outfitted with remotely operated pollen samplers. The comparison between model and measurements was conducted in two steps. In the first step, the LS model was used in combination with the rotorod samplers to estimate the pollen release rate Q for each sampling period. In the second step, a modeled value for the concentration Cmodel, corresponding to each RPV measured value Cmeasure, was calculated by simulating the RPV flight path through the LS model pollen plume corresponding to the atmospheric conditions, field geometry, wind direction, and source strength. The geometric mean and geometric standard deviation of the ratio Cmodel/Cmeasure over all of the sampling periods, except those determined to be upwind of the field, were 1.42 and 4.53, respectively, and the lognormal distribution corresponding to these values was found to fit closely the PDF of Cmodel/Cmeasure. Model output was sensitive to the turbulence parameters, with a factor-of-100 difference in the average value of Cmodel over the range of values encountered during the experiment. In comparison with this large potential variability, it is concluded that the average factor of 1.4 between Cmodel and Cmeasure found here indicates that the LS model is capable of accurately predicting, on average, concentrations over a range of atmospheric conditions.

Interference of the Histone Deacetylase Inhibits Pollen Germination and Pollen Tube Growth in Picea wilsonii Mast

PubMed Central

Zhou, Junhui; Li, Xiaojuan

2015-01-01

Histone deacetylase (HDAC) is a crucial component in the regulation of gene expression in various cellular processes in animal and plant cells. HDAC has been reported to play a role in embryogenesis. However, the effect of HDAC on androgamete development remains unclear, especially in gymnosperms. In this study, we used the HDAC inhibitors trichostatin A (TSA) and sodium butyrate (NaB) to examine the role of HDAC in Picea wilsonii pollen germination and pollen tube elongation. Measurements of the tip-focused Ca2+ gradient revealed that TSA and NaB influenced this gradient. Immunofluorescence showed that actin filaments were disrupted into disorganized fragments. As a result, the vesicle trafficking was disturbed, as determined by FM4-64 labeling. Moreover, the distribution of pectins and callose in cell walls was significantly altered in response to TSA and NaB. Our results suggest that HDAC affects pollen germination and polarized pollen tube growth in Picea wilsonii by affecting the intracellular Ca2+ concentration gradient, actin organization patterns, vesicle trafficking, as well as the deposition and configuration of cell wall components. PMID:26710276

Allergy immunotherapy with a hypoallergenic recombinant birch pollen allergen rBet v 1-FV in a randomized controlled trial.

PubMed

Klimek, Ludger; Bachert, Claus; Lukat, Karl-Friedrich; Pfaar, Oliver; Meyer, Hanns; Narkus, Annemie

2015-01-01

Pollen extracts and chemically modified allergoids are used successfully in allergen immunotherapy (AIT). Recombinant extracts offer potential advantages with respect to pharmaceutical quality, standardization and dosing. A hypoallergenic recombinant folding variant of the major birch pollen allergen (rBet v 1-FV) was compared with an established native birch preparation. A pre-seasonal, randomized, actively controlled phase II study was performed in birch pollen allergic rhino-conjunctivitis with or without asthma, GINA I/ II. 51 patients (24 rBet v 1-FV, 27 native extract) started therapy with subcutaneous allergen immunotherapy (SCIT). Primary end-point was a combined symptom medication score (SMS), changes in nasal provocation test, visual rating score and specific antibody responses secondary end-points. After one pre-seasonal treatment course the combined SMS was 5.86 (median; IQR: 14.02) for the rBet v 1-FV group versus 12.40 (median; IQR: 9.32) for the comparator during the three weeks pollen season (p = 0.330). After treatment in the second year, scores were 3.00 (median; IQR: 6.50) and 2.93 (4.86) respectively. Allergen tolerance in a nasal provocation test improved to a comparable extent in both groups. Significant increases in birch pollen-specific IgG1 and IgG4 were observed in both treatment groups following the first treatment phase and remained significantly raised until the end of the study. In this first in man, proof of concept phase II trial no statistical difference between rBet v 1-FV and an established natural pollen extract could be observed. rBet v 1-FV could be administered in higher doses than the native protein with no increase in adverse effects. The study was registered in clinicalTrials.gov (NCT00266526).

Comparison of the efficacy and safety of pollen allergen extracts using skin prick testing and serum specific IgE as references.

PubMed

Visitsunthorn, Nualanong; Visitsuntho, Kittipos; Pacharn, Punchama; Jirapongsananuruk, Orathai; Bunnag, Chaweewan

2017-12-01

Allergen extracts may be different due to the difference in dissemination of allergen-containing species in various geographical areas. Therefore, we wish to develop our own extracts to ensure the precision and quality of diagnosis. To compare the efficacy and safety of our locally prepared pollen allergen extracts to imported ones, using skin prick testing (SPT) and serum specific IgE (sIgE) as references. This prospective, randomized, double-blinded, self-controlled study was performed in respiratory allergic adult volunteers who are sensitized to at least one kind of pollen. Each subject was pricked with our Bermuda grass, Johnson grass and careless weed pollen allergen extracts, and also with the imported ones. sIgE levels were measured by using ImmunoCAP?. In 68 volunteers, our Bermuda, Johnson and careless weed extracts showed 91.2%, 45.6% and 54.4% positive SPTs, respectively, while for the imported ones 73.5%, 45.6% and 54.4% SPTs were positive, respectively. No adverse reaction was found in all procedures. The concentration of 10,000 BAU/mL of Bermuda grass, 1 : 20 w/v or 10,000 PNU/mL of Johnson grass and 1 : 40 w/v or 10,000 PNU/mL of careless weed yielded the most positive SPT results. There was no significant difference in mean wheal diameter (MWD) yielded from using local and imported extracts. Significant correlation was found between MWDs of imported pollen extracts and serum sIgE levels (p < 0.01). No significant difference between SPT results of local and imported pollen allergen extracts was found. Significant correlation was found between MWDs of imported pollen extract SPT and serum sIgE levels.

[Determination of myclobutanil and difenoconazole residues in pollen and honey of litchi by high performance liquid chromatography-tandem mass spectrometry].

PubMed

Wang, Siwei; Liu, Yanping; Sun, Haibin; DU, Lanjuan; Xu, Nengli

2018-01-08

An effective method was developed for the determination of two major fungicides including myclobutanil and difenoconazole residues in pollen and honey of litchi by modified QuEChERS-high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The pollen and honey samples were all extracted by acetonitrile, the pollen samples were cleaned-up by 0.9 g anhydrous magnesium sulfate (MgSO 4 ), 0.15 g primary secondary amine (PSA) and 0.15 g C 18 ; the honey samples were cleaned-up by 0.9 g MgSO 4 and 0.15 g PSA. The 0.1% (v/v) formic acid aqueous solution-acetonitrile (25:75, v/v) were used as the mobile phases. The extracts were separated on a Poroshell-120 EC-C 18 chromatographic column, the positive electrospray ion (ESI + ) source and selected ion monitoring (SIM) mode were used. The analytes were quantified by the matrix matching standard solutions. The matrix matched standard solutions of myclobutanil and difenoconazole showed good linearities in the range of 1-100 μg/L, and the correlation coefficients ( r 2 ) were all above 0.9990. The limits of detection (LODs) of myclobutanil and difenoconazole were 0.25 μg/kg and 0.50 μg/kg, respectively. The limits of quantification (LOQs) of myclobutanil and difenoconazole were 0.83 μg/kg and 1.7 μg/kg, respectively. The average recoveries of myclobutanil and difenoconazole in pollen and honey samples were 87.0%-95.2% and 90.1%-96.4% with the relative standard deviations of 1.2%-3.6% and 0.7%-4.1%, respectively. The method is quick, easy and sensitive, and it is suitable for the rapid determination and trace analysis of myclobutanil and difenoconazole in pollens and honeys of litchi. The method can provide data support for the exposure risk assessment of bees and other pollination insects.

Floral Preference of Melipona eburnea Friese (Hymenoptera: Apidae) in a Colombian Andean Region.

PubMed

Obregon, D; Nates-Parra, G

2014-02-01

Melipona eburnea Friese is a stingless bee kept in some regions of Colombia, where it is reported to be vulnerable to extinction due to habitat disturbance. To contribute to raising conservation strategies, the aim of this study was to identify the floral preferences of this species using melissopalynological analysis. A total of 31 pollen pot samples and 37 honey samples were taken from March 2009 through March 2010 from four colonies in Fusagasuga, Colombia. We found 92 pollen types: 17 from pollen pot samples, 39 from honey samples (indicating the sources of nectar), and 36 in both types of samples. The most frequent pollen types in the pollen pot samples were Myrcia type (100%), Eucalyptus globulus (96.9%), and Fraxinus uhdei (96.9%). The most frequent pollen types in honey samples were E. globulus (97.4%) and Myrcia type (94.9%). The pollen types corresponded mainly to native plants (68%), trees (44.5%), plants whose sexual system is hermaphroditic (56.5%), and plants with inflorescences (76.2%). The most frequent shapes of the flowers were brush-like (type Myrtaceae) and dish-like (type Asteraceae), and the preferred flower colors were white or cream (52.2%). In general, we found that M. eburnea showed a strong preference for trees of the family Myrtaceae to obtain nectar and pollen, including native and introduced species. Some other families are contributing significantly, such as Melastomataceae for pollen collection and Asteraceae for nectar. These results highlight the key plant species for the diet of M. eburnea.

Clinical implications of mast cell involvement in allergic conjunctivitis.

PubMed

Elieh Ali Komi, D; Rambasek, T; Bielory, L

2018-03-01

The conjunctiva is a common site for the allergic inflammatory response due to it being highly vascularized, having constant exposure to environmental pollutants and allergenic pollens and having a unique conjunctival associated lymphoid tissue. The primary morbidity of anterior surface conjunctival disorders that include allergic conjunctivitis and tear film disorders is associated with its high frequency of involvement rather than its severity, although the more chronic forms can involve the cornea and lead to sight-threatening conditions. Ocular allergy is associated with IgE-mediated mast cell activation in conjunctival tissue leading to the release of preformed mediators including histamine and proteases and subsequent de novo formation of lipid-derived mediators and cytokines that trigger a cascade of cellular and molecular events leading to extensive migration and infiltration of inflammatory cells to the ocular surface. The trafficking of neutrophils, eosinophils, and lymphocytes to the ocular surface is due to establishing various chemokine gradients (mainly CCL11, CCL24, CCL5, MCP-3, and MCP-4), cell surface expression of adhesion molecules (such as VCAM-1 the ligand for VLA-4), and leukocyte adhesion to vascular endothelium. The release of preformed mediators underlies the acute ocular surface response while the secondary influx of inflammatory cells leading to the recruitment and activation of eosinophils and the subsequent activation of Th2 and Th1 lymphocytes at the level of the conjunctiva reflects the late-phase reaction. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Nutrigenomics in honey bees: digital gene expression analysis of pollen's nutritive effects on healthy and varroa-parasitized bees

PubMed Central

2011-01-01

Background Malnutrition is a major factor affecting animal health, resistance to disease and survival. In honey bees (Apis mellifera), pollen, which is the main dietary source of proteins, amino acids and lipids, is essential to adult bee physiological development while reducing their susceptibility to parasites and pathogens. However, the molecular mechanisms underlying pollen's nutritive impact on honey bee health remained to be determined. For that purpose, we investigated the influence of pollen nutrients on the transcriptome of worker bees parasitized by the mite Varroa destructor, known for suppressing immunity and decreasing lifespan. The 4 experimental groups (control bees without a pollen diet, control bees fed with pollen, varroa-parasitized bees without a pollen diet and varroa-parasitized bees fed with pollen) were analyzed by performing a digital gene expression (DGE) analysis on bee abdomens. Results Around 36, 000 unique tags were generated per DGE-tag library, which matched about 8, 000 genes (60% of the genes in the honey bee genome). Comparing the transcriptome of bees fed with pollen and sugar and bees restricted to a sugar diet, we found that pollen activates nutrient-sensing and metabolic pathways. In addition, those nutrients had a positive influence on genes affecting longevity and the production of some antimicrobial peptides. However, varroa parasitism caused the development of viral populations and a decrease in metabolism, specifically by inhibiting protein metabolism essential to bee health. This harmful effect was not reversed by pollen intake. Conclusions The DGE-tag profiling methods used in this study proved to be a powerful means for analyzing transcriptome variation related to nutrient intake in honey bees. Ultimately, with such an approach, applying genomics tools to nutrition research, nutrigenomics promises to offer a better understanding of how nutrition influences body homeostasis and may help reduce the susceptibility of bees to (less virulent) pathogens. PMID:21985689

Sensitive Detection of Neonicotinoid Insecticides and Other Selected Pesticides in Pollen and Nectar Using Nanoflow Liquid Chromatography Orbitrap Tandem Mass Spectrometry.

PubMed

Moreno-González, David; Alcántara-Durán, Jaime; Gilbert-López, Bienvenida; Beneito-Cambra, Miriam; Cutillas, Víctor M; Rajski, Łukasz; Molina-Díaz, Antonio; García-Reyes, Juan F

2018-03-01

In this work, a new method based on nanoflow LC with high-resolution MS was developed for the determination of eight pesticides in pollen and nectar samples, including neonicotinoid insecticides and other selected pesticides commonly found in bees and beeswax. Detection was undertaken with a hybrid quadrupole-Orbitrap mass spectrometer (Q Exactive™) equipped with a commercial nanospray ion source. The extraction of pesticides from pollen samples was performed by a modified micro-QuEChERS method scaled down to Eppendorf tubes, whereas nectar samples were simply diluted with a water-methanol (95 + 5, v/v) solution. Good linearity (>0.999 in all cases) was obtained between 0.05 and 500 µg/kg and between 0.04 and 400 µg/kg for pollen and nectar, respectively. Recovery rates in pollen ranged from 85 to 97%, with RSDs <12%. Matrix effect was evaluated and showed negligible effects for all studied pesticides. The lowest concentration levels tested and validated were 0.5 and 0.4 µg/kg for pollen and nectar matrixes, respectively. In addition, selected incurred samples were studied, obtaining several positive findings in pollen and nectar samples, demonstrating the sensitivity and applicability of the proposed method.

Stigmatic exudate in the Annonaceae: Pollinator reward, pollen germination medium or extragynoecial compitum?

PubMed Central

Lau, Jenny Y. Y.; Pang, Chun‐Chiu; Ramsden, Lawrence

2017-01-01

Abstract Although “dry‐type” stigmas are widely regarded as ancestral in angiosperms, the early‐divergent family Annonaceae has copious stigmatic exudate. We evaluate three putative functions for this exudate: as a nutritive reward for pollinators; as a pollen germination medium; and as an extragynoecial compitum that enables pollen tube growth between carpels. Stigmatic exudate is fructose dominated (72.2%), but with high levels of glucose and sucrose; the dominance of hexose sugars and the diversity of amino acids observed, including many that are essential for insects, support a nutritive role for pollinators. Sugar concentration in pre‐receptive flowers is high (28.2%), falling during the peak period of stigmatic receptivity (17.4%), and then rising again toward the end of the pistillate phase (32.9%). Pollen germination was highest in sugar concentrations <20%. Sugar concentrations during the peak pistillate phase therefore provide optimal osmolarity for pollen hydration and germination; subsequent changes in sugar concentration during anthesis reinforce protogyny (in which carpels mature before stamens), enabling the retention of concentrated exudate into the staminate phase as a pollinator food reward without the possibility of pollen germination. Intercarpellary growth of pollen tubes was confirmed: the exudate therefore also functions as a suprastylar extragynoecial compitum, overcoming the limitations of apocarpy. PMID:28880427

Interspecific differences in the effects of sulfur dioxide on angiosperm sexual reproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

DuBay, D.T.

1981-01-01

The major objective of this study was to test the potential direct effects of SO/sub 2/ on sexual reproduction in several plant species with different reproductive structures and processes. In marked contrast to the sensitivity to SO/sub 2/ reported by other investigators for pollen germination and pollen tube growth in vitro, and recorded for Lepidium virginicum in this study, 4 of 5 species tested were tolerant with respect to fruit and seed set after exposure to 0.6 ppm SO/sub 2/ for 8 hours during flowering. Seed set in the one sensitive species, Geranium carolinianum, was reduced 40% from the controlmore » after exposure to SO/sub 2/, but only when relative humidity (RH) was at or above 90%. The effect of SO/sub 2/ on Lepidium pollen germination in vitro was greater than the effect of SO/sub 2/ on sexual reproduction in vivo. Sulfur dioxide reduced pollen germination in vitro 94% from the control. The same concentration of SO/sub 2/, at 90% Rh, reduced pollen germination in vivo 50% from the control, but had no effect on seed set. Predictions of effects of SO/sub 2/ on reproduction in vivo based on effects of SO/sub 2/ on pollen germination and pollen tube growth in vitro are not valid.« less

Role of Skin Prick Test in Allergic Disorders: A Prospective Study in Kashmiri Population in Light of Review

PubMed Central

Rasool, Roohi; Shera, Irfan Ali; Nissar, Saniya; Shah, Zaffar A; Nayak, Niyaz; Siddiqi, Mushtaq A; Sameer, Aga Syed

2013-01-01

Background: Skin prick test (SPT) is the most effective diagnostic test to detect IgE mediated type I allergic reactions like allergic rhinitis, atopic asthma, acute urticaria, food allergy etc. SPTs are done to know allergic sensitivity and applied for devising immunotherapy as the therapeutic modality. Materials and Methods: This prospective study was conducted in the department of Immunology and Molecular medicine at SKIMS. A total of 400 patients suffering from allergic rhinitis, asthma and urticaria were recruited in this study. SPT was performed with panel of allergens including house dust mite, pollens, fungi, dusts, cockroach, sheep wool and dog epithelia. Allergen immunotherapy was given to allergic rhinitis and asthmatic patients as therapeutic modality. Results: In our study, age of patients ranged from 6 to 65 years. Majority of patients were in the age group of 20-30 years (72%) with Male to female ratio of 1:1.5. Of the 400 patients, 248 (62%) had urticaria, 108 (27%) patients had allergic rhinitis and 44 (11%) patients had asthma. SPT reaction was positive in 38 (86.4%) with allergic asthma, 74 (68.5%) patients with allergic rhinitis and 4 (1.6%) patient with urticaria, respectively. Allergen immunotherapy was effective in 58% patients with allergic rhinitis and 42% allergic asthma. Conclusion: Identifiable aeroallergen could be detected in 86.4% allergic asthma and 68.5% allergic rhinitis patients by SPT alone. Pollens were the most prevalent causative allergen. There was significant relief in the severity of symptoms, medication intake with the help of allergen immunotherapy. PMID:23372205

Tolerance induction after specific immunotherapy with pollen allergoids adjuvanted by monophosphoryl lipid A in children

PubMed Central

Rosewich, M; Schulze, J; Eickmeier, O; Telles, T; Rose, M A; Schubert, R; Zielen, S

2010-01-01

Specific immunotherapy (SIT) is a well-established and clinically effective treatment for allergic diseases. A pollen allergoid formulated with the T helper type 1 (Th1)-inducing adjuvant monophosphoryl lipid A (MPL) facilitates short-term SIT. Little is known about mechanisms of tolerance induction in this setting. In a prospective study, 34 patients allergic to grass pollen (25 male, nine female, median age 10·2 years) received a total of 44 SIT courses (20 in the first, 24 in the second) with MPL-adjuvanted pollen allergoids. Immunogenicity was measured by levels of specific immunoglobulin G (IgGgrass) and IgG4grass by antibody blocking properties on basophil activation, and by induction of CD4+, CD25+ and forkhead box P3 (FoxP3+) regulatory T cells (Treg). Specific IgG and IgG4 levels increased only slightly in the first year of SIT. In the second year these changes reached significance (P < 0·0001). In keeping with these findings, we were able to show an increase of Treg cells and a decreased release of leukotrienes after the second year of treatment. In the first year of treatment we found little evidence for immunological changes. A significant antibody induction was seen only after the second course of SIT. Short-course immunotherapy with pollen allergoids formulated with the Th1-inducing adjuvant MPL needs at least two courses to establish tolerance. PMID:20345983

Tolerance induction after specific immunotherapy with pollen allergoids adjuvanted by monophosphoryl lipid A in children.

PubMed

Rosewich, M; Schulze, J; Eickmeier, O; Telles, T; Rose, M A; Schubert, R; Zielen, S

2010-06-01

Specific immunotherapy (SIT) is a well-established and clinically effective treatment for allergic diseases. A pollen allergoid formulated with the T helper type 1 (Th1)-inducing adjuvant monophosphoryl lipid A (MPL) facilitates short-term SIT. Little is known about mechanisms of tolerance induction in this setting. In a prospective study, 34 patients allergic to grass pollen (25 male, nine female, median age 10.2 years) received a total of 44 SIT courses (20 in the first, 24 in the second) with MPL-adjuvanted pollen allergoids. Immunogenicity was measured by levels of specific immunoglobulin G (IgG(grass)) and IgG4(grass) by antibody blocking properties on basophil activation, and by induction of CD4(+), CD25(+) and forkhead box P3 (FoxP3(+)) regulatory T cells (T(reg)). Specific IgG and IgG4 levels increased only slightly in the first year of SIT. In the second year these changes reached significance (P < 0.0001). In keeping with these findings, we were able to show an increase of T(reg) cells and a decreased release of leukotrienes after the second year of treatment. In the first year of treatment we found little evidence for immunological changes. A significant antibody induction was seen only after the second course of SIT. Short-course immunotherapy with pollen allergoids formulated with the Th1-inducing adjuvant MPL needs at least two courses to establish tolerance.

Reproductive phenology of transgenic Brassica napus cultivars: Effect on intraspecific gene flow.

PubMed

Simard, Marie-Josée; Légère, Anne; Willenborg, Christian J

2009-01-01

Pollen-mediated gene flow in space is well documented and isolation distances are recommended to ensure genetic purity of Brassica napus seed crops. Isolation in time could also contribute to gene flow management but has been little investigated. We assessed the effects of asynchronous and synchronous flowering on intraspecific B. napus gene flow by seeding adjacent plots of transgenic spring canola cultivars, either resistant to glyphosate or glufosinate, over a 0-4 week interval and measuring outcrossing rates and seed-set. Outcrossing rates, evaluated in the center of the first adjacent row, were reduced to the lowest level in plots flowering first when the seeding interval > 2 weeks. Increasing the time gap increased outcrossing rates in plots flowering second up to a seeding interval of two weeks. Flowers that opened during the last week of the flowering period produced fewer seed (< 10% of total seed production) and a smaller fraction of outcrossed seed (-25%). Observed time gap effects were likely caused by extraneous pollen load during the receptivity of productive seed-setting early flowers. Clearly, manipulation of B. napus flowering development through staggered planting dates can contribute to gene flow management. The approach will need to be validated by additional site-years and increased isolation distances.

Adaptive Significance of Flexistyly in Alpinia blepharocalyx (Zingiberaceae): A Hand-pollination Experiment

PubMed Central

Sun, Shan; Gao, Jiang-Yun; Liao, Wan-Jin; Li, Qing-Jun; Zhang, Da-Yong

2007-01-01

Background and Aims Flexistyly is a sexual dimorphism where there are two morphs that differ in the temporal expression of sexual function and also involve reciprocal movement of the stigmatic surface through a vertical axis during the flowering period. The adaptive significance of flexistyly has been interpreted as a floral mechanism for outcrossing, but it may also function to reduce sexual interference in which styles and stigmas impede the pollen export. Here these two explanations of flexistyly were tested in Alpinia blepharocalyx through a hand-pollination experiment. Methods Hand-pollinations were performed in two temporal morphs and consisted of two sequential pollination treatments, namely self-pollination in the morning and inter-morph pollination in the afternoon (treatment 1) or conversely inter-morph pollination in the morning and self-pollination in the afternoon (treatment 2), and two simultaneous self- and inter-morph cross-pollination treatments either in the morning (treatment 3) or in the afternoon (treatment 4). Seed paternity was then determined to assess relative success of self- versus cross-pollen using allozyme markers. Key Results In the sequential pollination treatments, whether the stigmas of recipients are receptive in the morning is crucial to the success of the pollen deposited. When the cataflexistylous (protandrous) morph served as pollen recipient, early-arriving pollen in the morning can sire only a very small proportion (<15%) of seeds because the stigmas were then unreceptive. However, when the anaflexistylous (protogynous) morph served as pollen recipient, early pollen did gain a large competitive advantage over the late pollen, particularly when cross-pollen arrived first. Simultaneous self- and inter-morph cross-pollination indicated that outcross-pollen is more competitive than self-pollen on receptive stigmas. Conclusions Differential maturing of male and female organs in Alpinia blepharocalyx is sufficient for selfing avoidance, obviating the need for style movements. Instead, the upward style curvature of the cataflexistylous morph in the morning and the anaflexistylous morph in the afternoon most likely represents a means of reducing interference with pollen export. PMID:17237211

Pollen Morphology and Boron Concentration in Floral Tissues as Factors Triggering Natural and GA-Induced Parthenocarpic Fruit Development in Grapevine

PubMed Central

Pérez-Díaz, Ricardo; Yáñez, Mónica; Tapia, Jaime; Moreno, Yerko

2015-01-01

Parthenocarpic fruit development (PFD) reduces fruit yield and quality in grapevine. Parthenocarpic seedless berries arise from fruit set without effective fertilization due to defective pollen germination. PFD has been associated to micronutrient deficiency but the relation of this phenomenon with pollen polymorphism has not been reported before. In this work, six grapevine cultivars with different tendency for PFD and grown under micronutrient-sufficient conditions were analyzed to determine pollen structure and germination capability as well as PFD rates. Wide variation in non-germinative abnormal pollen was detected either among cultivars as well as for the same cultivar in different growing seasons. A straight correlation with PFD rates was found (R2 = 0.9896), suggesting that natural parthenocarpy is related to defective pollen development. Such relation was not observed when PFD was analyzed in grapevine plants exposed to exogenous gibberellin (GA) or abscissic acid (ABA) applications at pre-anthesis. Increase (GA treatment) or reduction (ABA treatment) in PFD rates without significative changes in abnormal pollen was determined. Although these plants were maintained at sufficient boron (B) condition, a down-regulation of the floral genes VvBOR3 and VvBOR4 together with a reduction of floral B content in GA-treated plants was established. These results suggest that impairment in B mobility to reproductive tissues and restriction of pollen tube growth could be involved in the GA-induced parthenocarpy. PMID:26440413

Pollen Morphology and Boron Concentration in Floral Tissues as Factors Triggering Natural and GA-Induced Parthenocarpic Fruit Development in Grapevine.

PubMed

Alva, Orlando; Roa-Roco, Rosa Nair; Pérez-Díaz, Ricardo; Yáñez, Mónica; Tapia, Jaime; Moreno, Yerko; Ruiz-Lara, Simón; González, Enrique

2015-01-01

Parthenocarpic fruit development (PFD) reduces fruit yield and quality in grapevine. Parthenocarpic seedless berries arise from fruit set without effective fertilization due to defective pollen germination. PFD has been associated to micronutrient deficiency but the relation of this phenomenon with pollen polymorphism has not been reported before. In this work, six grapevine cultivars with different tendency for PFD and grown under micronutrient-sufficient conditions were analyzed to determine pollen structure and germination capability as well as PFD rates. Wide variation in non-germinative abnormal pollen was detected either among cultivars as well as for the same cultivar in different growing seasons. A straight correlation with PFD rates was found (R2 = 0.9896), suggesting that natural parthenocarpy is related to defective pollen development. Such relation was not observed when PFD was analyzed in grapevine plants exposed to exogenous gibberellin (GA) or abscissic acid (ABA) applications at pre-anthesis. Increase (GA treatment) or reduction (ABA treatment) in PFD rates without significative changes in abnormal pollen was determined. Although these plants were maintained at sufficient boron (B) condition, a down-regulation of the floral genes VvBOR3 and VvBOR4 together with a reduction of floral B content in GA-treated plants was established. These results suggest that impairment in B mobility to reproductive tissues and restriction of pollen tube growth could be involved in the GA-induced parthenocarpy.

Differences in dichogamy and herkogamy contribute to higher selfing in contrasting environments in the annual Blackstonia perfoliata (Gentianaceae)

PubMed Central

Brys, Rein; Geens, Bram; Beeckman, Tom; Jacquemyn, Hans

2013-01-01

Background and Aims The establishment of plant populations in novel environments may generate pronounced shifts in floral traits and plant mating systems, particularly when pollinators are scarce. In this study, floral morphology and mating system functioning are compared between recently established and older populations of the annual plant Blackstonia perfoliata that occur in different pollinator environments. Methods Hand-pollination and emasculation experiments were conducted to assess the extent of pollinator-mediated pollen deposition and pollen limitation, and the contribution of autonomous selfing to total seed production. Detailed measurements of key floral traits were performed to compare the flower morphology and mating system functioning between plants from both pollination environments. Key Results Pollinator-mediated pollen deposition was about twice as low in the recently colonized and pollinator-poor environment compared with the old and pollinator-rich sites, but total seed set was little affected by any type of pollen limitation. The contribution of autonomous selfing to total seed production was higher in the pollinator-poor sites than in the pollinator-rich sites (index of reproductive assurance = 0·56 and 0·17, respectively), and seed production was only poorly affected by selfing, whereas in the pollinator-rich populations selfing reduced total reproductive output by about 40 % compared with outcross pollination. Plants originating from pollinator-poor environments produced smaller flowers that showed significantly lower levels of dichogamy (i.e. protogyny) and herkogamy. These reductions resulted in a 2-fold higher capacity for autonomous selfing under pollinator-free conditions (index of autonomous selfing = 0·81 and 0·41 in plants originating from the pollinator-poor and pollinator-rich environment, respectively). Conclusions The results illustrate that plant populations colonizing novel environments can differ markedly in floral morphology and mating system functioning. Due to a temporal shift in the male phase, the breeding system of B. perfoliata shifted from delayed selfing under pollinator-rich conditions towards competing selfing in recently established populations, providing greater reproductive assurance when pollinators and/or reproductive partners are limited. PMID:23408833

Correspondence of terrestrial and marine paleoclimates, SW Florida, during Mid-Pliocene periods of global warmth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willard, D.A.; Cronin, T.M.; Litwin, R.J.

Pollen and ostracode samples from shallow-marine strata of the Pinecrest Beds near Sarasota, FL were studied to compare terrestrial and marine paleoclimate records during periods of middle Pliocene global warmth. Pollen assemblages from strata deposited during sea-level highstands from about 3.5--3.0 Ma are dominated by Pinus pollen with subdominant Ouercus and common taxodiaceous pollen, which increases markedly in abundance near about 3.0 Ma. Comparison with modern, shallow-marine pollen assemblages from the east coast of the United States indicates that the 3.5--3.0 Ma vegetation was, overall, similar to vegetation from the southern third Florida. However, near 3.0 Ma, pollen assemblages becomemore » less similar to modern assemblages due to higher percentages of taxodiaceous pollen and lower percentages of herbaceous pollen. Such changes are consistent with warmer climates and, possibly, moister soil conditions. Marine ostracodes also show progressively higher percentages of thermophilic (subtropical/tropical) taxa and decreasing percentages of cryophilic (temperature) taxa between 3.5--3.0 Ma. From about 2.5--2.0 Ma, ostracode assemblages recorded open-bay, sometimes brackish environments similar to those in subtropical eastern North America today. The Pinecrest paleoclimate record shows (1) that during two periods of global warmth and high sea level, subtropical terrestrial and marine climates were not substantially warmer than today; (2) ocean and atmosphere temperatures probably were about the same as today, perhaps slightly higher during peak warmth near 3.0 Ma; (3) changes in pollen assemblages appear to lag behind changes in ostracode assemblages; (4) progressively warmer local climates 3.5--3.0 Ma probably record an increasing influence of warm Gulf Stream water as the Central American Isthmus closed.« less

Sensitization to sunflower pollen: only an occupational allergy?

PubMed

Jiménez, A; Moreno, C; Martínez, J; Martínez, A; Bartolomé, B; Guerra, F; Palacios, R

1994-11-01

Sunflower (Helianthus annuus) pollen sensitization has been reported as an occupational allergy. In this report, the sensitization of the general population living in sunflower-growing areas to Helianthus pollen was studied. Both RAST results in 32 adults with summer symptoms previously diagnosed as allergic to Artemisia pollen, and cross-reactivity studies between H. annuus and other Compositae suggested that H. annuus pollen was the main allergen involved in the hypersensitivity reaction of those patients. Good correlation was found between RAST and SPT to Helianthus and between RAST and conjunctival provocation test to Helianthus. Bronchial challenge tests performed on 8 of the 32 patients confirmed the clinical implication of Helianthus pollen in suspected subjects. Five workers, handling sunflower pollen, who suffered from related symptoms were subjected to the same study, showing lesser wheal areas and lesser specific IgE levels than a non-worker group. Thirteen patients with RAST values > or = class 2 showed 2 IgE-binding fractions at 34.0 and 42.8 kD in 65% of sera and 3 IgE-binding fractions at pI 4.9, 9.6 and 10.2 in 54% of sera. By means of micropreparative high-resolution chromatography, it was possible to purify a 34-kD major allergen. Analysis performed by RAST inhibition with sera from atopic patients and ELISA inhibition with experimental anti-Helianthus rabbit sera demonstrated a cross-reactivity between Helianthus and other Compositae, but low affinity of specific anti-Helianthus antibodies for heterologous antigens. Taking into account the above-mentioned data, and the high prevalence of Helianthus pollen in the atmosphere during harvesting (in spite of its entomophilous character), Helianthus pollen should be considered as an allergenic source to be investigated in the general population living in sunflower-growing regions suffering from seasonal summer allergy.

Consistent pollen nutritional intake drives bumble bee (Bombus impatiens) colony growth and reproduction across different habitats.

PubMed

Vaudo, Anthony D; Farrell, Liam M; Patch, Harland M; Grozinger, Christina M; Tooker, John F

2018-06-01

Foraging behavior is a critical adaptation by insects to obtain appropriate nutrients from the environment for development and fitness. Bumble bees ( Bombus spp.) form annual colonies which must rapidly increase their worker populations to support rearing reproductive individuals before the end of the season. Therefore, colony growth and reproduction should be dependent on the quality and quantity of pollen resources in the surrounding landscape. Our previous research found that B. impatiens foraging preferences to different plant species were shaped by pollen protein:lipid nutritional ratios (P:L), with foragers preferring pollen species with a ~5:1 P:L ratio. In this study, we placed B. impatiens colonies in three different habitats (forest, forest edge, and valley) to determine whether pollen nutritional quality collected by the colonies differed between areas that may differ in resource abundance and diversity. We found that habitat did not influence the collected pollen nutritional quality, with colonies in all three habitats collecting pollen averaging a 4:1 P:L ratio. Furthermore, there was no difference in the nutritional quality of the pollen collected by colonies that successfully reared reproductives and those that did not. We found however, that "nutritional intake," calculated as the colony-level intake rate of nutrient quantities (protein, lipid, and sugar), was strongly related to colony growth and reproductive output. Therefore, we conclude that B. impatiens colony performance is a function of the abundance of nutritionally appropriate floral resources in the surrounding landscape. Because we did not comprehensively evaluate the nutrition provided by the plant communities in each habitat, it remains to be determined how B. impatiens polylectic foraging strategies helps them select among the available pollen nutritional landscape in a variety of plant communities to obtain a balance of key macronutrients.

Prevalence of Skin Sensitization to Pollen of Date Palm in Marrakesh, Morocco.

PubMed

Serhane, Hind; Amro, Lamyae; Sajiai, Hafsa; Alaoui Yazidi, Abdelhaq

2017-01-01

Background . Date palm's pollen has been identified as a source of allergy; the rate of sensitization of this pollen is between 6 and 29%. Objective . To determine the prevalence of sensitization to date palm in Marrakesh and to identify the clinical profile. Patients and Methods . This study is based on a questionnaire and the prick test on 7 allergens, in population aged 5 years and above with clinical symptoms suggesting allergic diseases, from November 2012 to February 2013 in Marrakech. Results . We included 468 patients (women: 79.5%). The prick tests were considered interpretable in 467 cases. The prevalence of skin sensitization to pollen of date palm was 6.6%. The 31 cases of sensitization to date palm involved 7 men and 24 women with an average age of 37.5 years. Cutaneous monosensitization to date palm's pollen was observed in 2 cases. Asthma, rhinitis, and conjunctivitis were recorded, respectively, in 48.4%, 93.5%, and 67.7%. Conclusion . Skin sensitization to pollen of date palm does not seem unusual among allergic patients in Marrakech and is comparable to that found in Casablanca (7%), Barcelona (6.6%), and Cartagena (6.1%).

Cloning and expression of cyclophilin from Platanus orientalis pollens in Escherichia coli

PubMed Central

Sankian, Mojtaba; Vahedi, Fatemeh; Pazouki, Nazanin; Moghadam, Malihe; Jabbari Azad, Farahzad; Varasteh, Abdol-Reza

2012-01-01

Background: Allergy is a clinical disorder affecting the human population with wide geographical distribution. Platanus orientalis (P. orientalis) trees are planted in many countries and their pollen causes allergic reactions. Cyclophilin has recently been identified as one of the most important allergens of P. orientalis pollen. We aimed to clone and purify this allergen in Escherichia coli for further studies and therapeutic and diagnostic purposes for allergy to P. orientalis. Methods: RNA was extracted from P. orientalis. A full-length fragment encoding cyclophilin was prepared by polymerase chain reaction amplification of the first-strand cDNA synthesized from P. orientalis RNA. The cDNA was inserted into the pET32b (+) vector, and the construct transformed into E. coli Top10 and BL21 cells. The expressed protein was purified by the CuSO4 method. Results: The cDNA for the cyclophilin of P. orientalis pollen was cloned, and a specific reactivity of recombinant cyclophin was confirmed by immunoblotting using sera from patients allergic to P. orientalis pollen. Conclusion: The recombinant cyclophilin has a potential for immunologic assays for evaluation of allergy to P. orientalis pollen. PMID:26989705

Sensitization to sunflower pollen and lung functions in sunflower processing workers.

PubMed

Atis, S; Tutluoglu, B; Sahin, K; Yaman, M; Küçükusta, A R; Oktay, I

2002-01-01

This study aimed to investigate whether exposure to sunflower pollen (Helianthus annuus) increases both sensitization and respiratory symptoms, and whether or not it affects lung functions in sunflower processing workers. The largest sunflower processing factories in the Thrace region of Turkey participated in this study. Workers from the units directly exposed to sunflower seed enrolled as the study group (n = 102) and workers who were not directly exposed to Helianthus annuus pollen (n = 102) were the control group. Detailed questionnaires covering respiratory and allergic symptoms were completed, and skin prick tests and lung function tests were performed. We found a very high rate (23.5%) of sensitization to Helianthus annuus in the study group compared to the controls (P<0.001). Logistic regression analysis showed that the risk of sensitization to H. annuus was increased 4.7-fold (odds ratio = 4.17, 95%) confidence interval = 1.3-16.7) if subjects were exposed to sunflower pollen in the workplace. While asthmatic symptoms and allergic skin diseases were not different between the two groups, workers in the study group had a higher rate of allergic rhinitis and conjunctivitis (P<0.05). We found that pulmonary function was significantly impaired in the study group (P<0.01). Using a multivariate analysis model, inclusion in the study group was found to be a predictive factor for impairment of lung function (P=0.002). We conclude that sunflower pollen has high allergenic potential, especially when there is close contact, and exposure to sunflower pollen in the workplace can result in impairment in lung function.

Effect of enhanced UV-B radiation on pollen quantity, quality, and seed yield in Brassica rapa (Brassicaceae)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demchik, S.M.; Day, T.A.

Three experiments examined the influence of ultraviolet-B radiation (UV-B; 280-320 nm) exposure on reproduction in Brassica rapa (Brassicacaeae). Plants were grown in a greenhouse under three biologically effective UV-B levels that stimulated either an ambient stratospheric ozone level (control), 16% ({open_quotes}low enhanced{close_quotes}), or 32% ({open_quotes}high enhanced{close_quotes}) ozone depletion levels at Morgantown, WV, USA in mid-March. In the first experiment,pollen production and viability per flower were reduced by {approx}50% under both enhanced UV-B levels relative to ambient controls. While plants under high-enhanced UV-B produced over 40% more flowers than plants under the two lower UV-B treatments, whole-plant production of viable pollenmore » was reduced under low-enhanced UV-B to 34% of ambient controls. In the second experiment, the influence of source-plant UV-B exposure on in vitro pollen from plants was examined and whether source-plant UV-B exposure influenced in vitro pollen germination and viability. Pollen from plants under both enhanced-UV-B was reduced from 65 to 18%. Viability of the pollen from plants grown under both enhanced UV-B treatments was reduced to a much lesser extent: only from {approx}43 to 22%. Thus, ambient source-plant pollen was more sensitive to enhanced UV-B levels to fertilize plants growing under ambient-UV-B levels, and assessed subsequent seed production and germination. Seed abortion rates were higher in plants pollinated with pollen from the enhanced UV-B treatments, than from ambient UV-B. Despite this, seed yield (number and mass) per plant was similar, regardless of the UV-B exposure of their pollen source. Our findings demonstrate that enhanced UV-B levels associated with springtime ozone depletion events have the capacity to substantially reduce viable pollen production, and could ultimately reduce reproductive success of B. rapa. 37 refs., 4 figs., 2 tabs.« less

Enhanced concentrations of citric acid in spring aerosols collected at the Gosan background site in East Asia

NASA Astrophysics Data System (ADS)

Jung, Jinsang; Kawamura, Kimitaka

2011-09-01

In order to investigate water-soluble dicarboxylic acids and related compounds in the aerosol samples under the Asian continent outflow, total suspended particle (TSP) samples ( n = 32) were collected at the Gosan site in Jeju Island over 2-5 days integration during 23 March-1 June 2007 and 16-24 April 2008. The samples were analyzed for water-soluble dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls using a capillary gas chromatography technique. We found elevated concentrations of atmospheric citric acid (range: 20-320 ng m -3) in the TSP samples during mid- to late April of 2007 and 2008. To specify the sources of citric acid, dicarboxylic acids and related compounds were measured in the pollen sample collected at the Gosan site (Pollen_Gosan), authentic pollen samples from Japanese cedar ( Cryptomeria) (Pollen_cedar) and Japanese cypress ( Chamaecyparis obtusa) (Pollen_cypress), and tangerine fruit produced from Jeju Island. Citric acid (2790 ng in unit mg of pollen mass) was found as most abundant species in the Pollen_Gosan, followed by oxalic acid (2390 ng mg -1). Although citric acid was not detected in the Pollen_cedar and Pollen_cypress as major species, it was found as a dominant species in the tangerine juice while malic acid was detected as major species in the tangerine peel, followed by oxalic and citric acids. Since Japanese cedar trees are planted around tangerine farms to prevent strong winds from the Pacific Ocean, citric acid that may be directly emitted from tangerine is likely adsorbed on pollens emitted from Japanese cedar and then transported to the Gosan site. Much lower malic/citric acid ratios obtained under cloudy condition than clear condition suggest that malic acid may rapidly decompose to lower molecular weight compounds such as oxalic and malonic acids (

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stairs, G. R.

The production of pollen under conditions of chronic gamma irradiation was investigated for three oak species. Two chronically irradiated areas were studied: a low level (1 to 15r/day) area where trees had received varying amounts of radiation over a period of 11 years, and a second area receiving gamma radiation for about five months previous to the investigation. In the latter study dose levels ranged from lethal (45r/day) to a region of no detectable effect. In both areas pollen abortion showed a significant increase with increasing radiation exposure, although germinable pollen was produced at all survival levels examined. The germinatingmore » pollen tube length did not show a significant decrease in the irradiated material examined. In addition to cytological effects there was a marked deiny in floral phenology for both areas. Acute irradiation of male flower buds at different stages of meiosis, and of mature pollen were reported. The radiosensitivity of microsporogenesis was evaluated by cytological scoring at anaphase I, and by pollen abortion, germination, and tube lengih. Both the number of chromosome fragments/100 cells scored at anaphase I and pollen abortion showed a linear increase with an increase in radiation exposure. Pollen germination and tube length were less effected by radiation (based on a percent of unaborted grains). It was suggested that a range of 1 kr to 4 kr will be appropriate for irradiating male flower buds of oak to be utilized in a mutation breeding program. Contingent upon additional studies the range of radiation recommended for flower buds is also suggested for the induction of mutations in pollen. Pollen was found to be highly resistant to radiation when evaluated by germination and tube growth studies. No effect was found with irradiation of 100 kr; at 300 kr both germination and tube lengths were depressed. At these levels it is probable that germination is an expression of cytoplasmic growth and not of nuclear viability. No significant difference was found between responses of the two species for either chronic or acute irradiation. (auth)« less

A molecular description of mutations affecting the pollen component of the Nicotiana alata S locus.

PubMed Central

Golz, J F; Su, V; Clarke, A E; Newbigin, E

1999-01-01

Mutations affecting the self-incompatibility response of Nicotiana alata were generated by irradiation. Mutants in the M1 generation were selected on the basis of pollen tube growth through an otherwise incompatible pistil. Twelve of the 18 M1 plants obtained from the mutagenesis screen were self-compatible. Eleven self-compatible plants had mutations affecting only the pollen function of the S locus (pollen-part mutants). The remaining self-compatible plant had a mutation affecting only the style function of the S locus (style-part mutant). Cytological examination of the pollen-part mutant plants revealed that 8 had an extra chromosome (2n + 1) and 3 did not. The pollen-part mutation in 7 M1 plants was followed in a series of crosses. DNA blot analysis using probes for S-RNase genes (encoding the style function of the S locus) indicated that the pollen-part mutation was associated with an extra S allele in 4 M1 plants. In 3 of these plants, the extra S allele was located on the additional chromosome. There was no evidence of an extra S allele in the 3 remaining M1 plants. The breakdown of self-incompatibility in plants with an extra S allele is discussed with reference to current models of the molecular basis of self-incompatibility. PMID:10388830

Inheritance of Hetero-Diploid Pollen S-Haplotype in Self-Compatible Tetraploid Chinese Cherry (Prunus pseudocerasus Lindl)

PubMed Central

Gu, Chao; Liu, Qing-Zhong; Yang, Ya-Nan; Zhang, Shu-Jun; Khan, Muhammad Awais; Wu, Jun; Zhang, Shao-Ling

2013-01-01

The breakdown of self-incompatibility, which could result from the accumulation of non-functional S-haplotypes or competitive interaction between two different functional S-haplotypes, has been studied extensively at the molecular level in tetraploid Rosaceae species. In this study, two tetraploid Chinese cherry (Prunus pseudocerasus) cultivars and one diploid sweet cherry (Prunus avium) cultivar were used to investigate the ploidy of pollen grains and inheritance of pollen-S alleles. Genetic analysis of the S-genotypes of two intercross-pollinated progenies showed that the pollen grains derived from Chinese cherry cultivars were hetero-diploid, and that the two S-haplotypes were made up of every combination of two of the four possible S-haplotypes. Moreover, the distributions of single S-haplotypes expressed in self- and intercross-pollinated progenies were in disequilibrium. The number of individuals of the two different S-haplotypes was unequal in two self-pollinated and two intercross-pollinated progenies. Notably, the number of individuals containing two different S-haplotypes (S1- and S5-, S5- and S8-, S1- and S4-haplotype) was larger than that of other individuals in the two self-pollinated progenies, indicating that some of these hetero-diploid pollen grains may have the capability to inactivate stylar S-RNase inside the pollen tube and grow better into the ovaries. PMID:23596519

Elevated temperature during reproductive development affects cone traits and progeny performance in Picea glauca x engelmannii complex.

PubMed

Webber, Joe; Ott, Peter; Owens, John; Binder, Wolfgang

2005-10-01

Two temperature regimes were applied during reproductive development of seed and pollen cones of interior spruce (Picea glauca (Moench) Voss and Picea engelmannii (Parry) complex) to determine temperature effects on the adaptive traits of progeny. In Experiment 1, identical crosses were made on potted interior spruce using untreated pollen followed by exposure to a day/night temperature of 22/8 or 14/8 degrees C with a 12-h photoperiod during the stages of reproductive development from post-pollination to early embryo development. Frost hardiness and growth of progeny from seed produced in the two temperature treatments were measured over a 4-year period. Elevated temperature significantly affected both seed-cone development and the adaptive properties of the progeny. Seed cones exposed to the 22/8 degrees C treatment reached the early embryo stage in 53 days versus 92 days in the 14/8 degrees C treatment. Seed yields, cotyledon emergence and percent germination were also significantly enhanced by the 22/8 degrees C treatment. Progeny from seed produced in the higher temperature treatment showed significantly reduced spring and fall frost hardiness, but the elevated temperature treatment had no significant effects on time of bud burst, growth patterns or final heights. In Experiment 2, single ramets of the same clone were subjected to a day/night temperature of 20/8 or 10/8 degrees C during pollen cone development, starting from meiosis and ending at pollen shedding. The two populations of pollen were then crossed with untreated seed cones. Compared with pollen cones exposed to the 10/8 degrees C treatment, pollen cones exposed to the 20/8 degrees C treatment during development reached the shedding stage 2-4 weeks earlier, whereas pollen yields, in vitro viability and fertility (seed set) were significantly lower; however, the resulting progeny displayed no treatment differences in frost hardiness or growth after 1 year. Results suggest that seed orchard after-effects could be caused by temperature differences between orchard site and parent tree origin and that this effect acts on maternal development. Gametophytic (pollen or megagametophyte or both) and early embryo (sporophytic) selection are possible mechanisms that may explain the observed results. Although the effects are biologically significant, they are relatively small and do not justify changes in current deployment strategies for seed orchard seed.

Treatment with grass allergen peptides improves symptoms of grass pollen-induced allergic rhinoconjunctivitis.

PubMed

Ellis, Anne K; Frankish, Charles W; O'Hehir, Robyn E; Armstrong, Kristen; Steacy, Lisa; Larché, Mark; Hafner, Roderick P

2017-08-01

Synthetic peptide immunoregulatory epitopes are a new class of immunotherapy to treat allergic rhinoconjunctivitis (ARC). Grass allergen peptides, comprising 7 synthetic T-cell epitopes derived from Cyn d 1, Lol p 5, Dac g 5, Hol l 5, and Phl p 5, is investigated for treatment of grass pollen-induced ARC. We sought to evaluate the efficacy, safety, and tolerability of intradermally administered grass allergen peptides. A multicenter, randomized, double-blind, placebo-controlled study evaluated 3 regimens of grass allergen peptides versus placebo in patients with grass pollen-induced allergy (18-65 years). After a 4-day baseline challenge to rye grass in the environmental exposure unit (EEU), subjects were randomized to receive grass allergen peptides at 6 nmol at 2-week intervals for a total of 8 doses (8x6Q2W), grass allergen peptides at 12 nmol at 4-week intervals for a total of 4 doses (4x12Q4W), or grass allergen peptides at 12 nmol at 2-week intervals for a total of 8 doses (8x12Q2W) or placebo and treated before the grass pollen season. The primary efficacy end point was change from baseline in total rhinoconjunctivitis symptom score across days 2 to 4 of a 4-day posttreatment challenge (PTC) in the EEU after the grass pollen season. Secondary efficacy end points and safety were also assessed. Two hundred eighty-two subjects were randomized. Significantly greater improvement (reduction of total rhinoconjunctivitis symptom score from baseline to PTC) occurred across days 2 to 4 with grass allergen peptide 8x6Q2W versus placebo (-5.4 vs -3.8, respectively; P = .0346). Greater improvement at PTC also occurred for grass allergen peptide 8x6Q2W versus placebo (P = .0403) in patients with more symptomatic ARC. No safety signals were detected. Grass allergen peptide 8x6Q2W significantly improved ARC symptoms after rye grass allergen challenge in an EEU with an acceptable safety profile. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

The potential of pollen-based quantitative vegetation reconstructions in studies of past human settlements and use of resources - examples from Europe

NASA Astrophysics Data System (ADS)

Gaillard, Marie-Jose; Cui, Qiao-Yu; Lemdahl, Geoffrey; Trondman, Anna-Kari

2015-04-01

There is a long tradition of collaboration between palaeoecologists and archaeologists in many parts of the world with the purpose of reconstructing the environment of humans through time and the study of the interactions between humans and their environment. Vegetation (i.e. vegetated landscapes and plants) has long been one of the most important parts of the environment for humans' resources. Thanks to the interpretation of palaeoecological data such as pollen and plant macrofossils, it is well known that humans have used plants for their subsistence and formed many landscapes of the Earth through their activities over many millennia. Pollen analysis in particular has been used to reconstruct the landscapes of humans in order i) to learn something on their use of the landscape for building material, grazing and food (e.g. woods, grazed land, cultivated fields), and ii) to understand their influence on the landscape through deforestation in particular. Pollen data as proxy records of vegetation have been very useful to provide qualitative descriptions of cultural landscapes through time in terms of the presence of major tree, shrub and herb species, and the character of the landscape, wooded, "half-wooded" (or partly wooded), and primarily open (poorly wooded) (1). Efforts to calibrate pollen onto land-use in the 1990ies has made possible to provide more precise and detailed interpretation of pollen records in terms of land-use type (2). However, when it came to questions related to the size of cultivated land or grazed land in relation to wooded land, interpretation of pollen records has been problematic until recently. The non-linear relationship between pollen and vegetation due to inter-taxonomic differences in pollen productivity and pollen dispersion and deposition characteristics of plant taxa has long hampered estimation of the percentage cover of plant taxa or landscape units in the past. Thanks to recent developments in pollen-vegetation modelling, a new approach - the Landscape Reconstruction Algorithm (LRA) (3, 4) - makes it possible to estimate the cover of plant taxa or landscape units at both regional and local spatial scales using pollen records. The LRA has been tested and applied in various types of studies in Europe in particular. Examples from Europe and Scandinavia show that pollen-based quantitative reconstructions of vegetation cover, in combination with other palaeoecological records such as insect and plant macroremains, show the great potential of such studies to provide new insights on the use of landscapes and vegetation by humans in the past and its environmental consequences at both regional and local spatial scales (5, 6). These results provide a new environmental framework for the discussion and testing of hypotheses based on archaeological data. (1) Berglund, B.E. (1991) Ecological Bulletins 41: 1-495. (2) Gaillard, M.-J. et al. (1994) Review of Palaeobotany and Palynology 82: 47-73. (3) Sugita, S. (2007a) The Holocene 17: 243-257. (4) Sugita, S. (2007b) The Holocene 17: 229-241. (5) Cui, Q.-Y. et al. (2014) Ecology and Evolution, doi: 10.1002/ece3.1198 (6) Trondman, A.-K. (2014) Global Change Biology, doi: 10.1111/gcb.12737

Concentrations of imidacloprid and thiamethoxam in pollen, nectar and leaves from seed-dressed cotton crops and their potential risk to honeybees (Apis mellifera L.).

PubMed

Jiang, Jiangong; Ma, Dicheng; Zou, Nan; Yu, Xin; Zhang, Zhengqun; Liu, Feng; Mu, Wei

2018-06-01

Neonicotinoid insecticides (NIs) have recently been recognized as co-factors in the decline of honeybee colonies because most neonicotinoids are systemic and can transfer into the pollen and nectar of many pollinated crops. In this study, we collected pollen, nectar and leaves from a cotton crop treated with imidacloprid and thiamethoxam to measure the residue levels of these two NIs at different application doses during the flowering period. Then, the residual data were used to assess the risk posed by the systemic insecticides to honeybees following mandated methods published by the European Food Safety Authority (EFSA), and a highly toxic risk to honeybees was highlighted. Imidacloprid was found in both pollen and nectar samples, whereas thiamethoxam was found in 90% of pollen samples and over 60% of nectar samples. Analysis of the pollen and nectar revealed residual amounts of imidacloprid ranging from 1.61 to 64.58 ng g -1 in the pollen and from not detected (ND) to 1.769 ng g -1 in the nectar. By comparison, the thiamethoxam concentrations in pollen and nectar ranged from ND to 14.521 ng g -1 and from ND to 4.285 ng g -1 , respectively. The results of this study provide information on the transfer of two NIs from seed treatment to areas of the plant and provides an understanding of the potential exposure of the bee and other pollinators to systemic insecticides. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Clinical Impact of Bet v 6 in Birch Pollen-Sensitized Patients.

PubMed

Gellrich, Donata; Eder, Katharina; San Nicoló, Marion; Berghaus, Alexander; Gröger, Moritz

2017-01-01

Bet v 6, a minor birch pollen allergen, is commercially available for allergen-specific IgE antibody testing. However, there is hardly any literature on the clinical impact of Bet v 6. The aim of the present study was to analyze if testing specific IgE against Bet v 6 can add valuable benefit to the standard diagnostics of birch pollen-sensitized patients, especially in patients with unknown sensitization-eliciting allergens. Birch pollen-sensitized patients with missing IgE reactivity against Bet v 1, 2, and 4 were tested for specific IgE antibodies against Bet v 6. For comparison, an equal number of randomly selected patients with birch pollen sensitization, regardless of their individual sensitization patterns, were tested for specific anti-Bet v 6. Of 57 cases with missing reactivity against the standard birch pollen allergens, 2 patients were positive for Bet v 6. In the representative sample, 3 patients showed specific IgE against Bet v 6 - resulting in a total prevalence of 5%. None of the Bet v 6-positive patients showed allergic symptoms after exposure to birch pollen or an oral allergy syndrome. An increased prevalence of asthma and a higher degree of sensitization were the only distinctive clinical features in Bet v 6-positive patients. Among birch pollen-sensitized patients, the prevalence of specific IgE against Bet v 6 is low. Further, sensitization to Bet v 6, which shows characteristics of a panallergen, remains clinically silent. Therefore, determination of anti-Bet v 6 is not considered useful in the clinical routine. © 2017 S. Karger AG, Basel.

Pollen-limited reproduction in blue oak: Implications for wind pollination in fragmented populations

USGS Publications Warehouse

Knapp, E.E.; Goedde, M.A.; Rice, K.J.

2001-01-01

Human activities are fragmenting forests and woodlands worldwide, but the impact of reduced tree population densities on pollen transfer in wind-pollinated trees is poorly understood. In a 4-year study, we evaluated relationships among stand density, pollen availability, and seed production in a thinned and fragmented population of blue oak (Quercus douglasii). Geographic coordinates were established and flowering interval determined for 100 contiguous trees. The number of neighboring trees within 60 m that released pollen during each tree's flowering period was calculated and relationships with acorn production explored using multiple regression. We evaluated the effects of female flower production, average temperature, and relative humidity during the pollination period, and number of pollen-producing neighbors on individual trees' acorn production. All factors except temperature were significant in at least one of the years of our study, but the combination of factors influencing acorn production varied among years. In 1996, a year of large acorn crop size, acorn production was significantly positively associated with number of neighboring pollen producers and density of female flowers. In 1997, 1998, and 1999, many trees produced few or no acorns, and significant associations between number of pollen-producing neighbors and acorn production were only apparent among moderately to highly reproductive trees. Acorn production by these reproductive trees in 1997 was significantly positively associated with number of neighboring pollen producers and significantly negatively associated with average relative humidity during the pollination period. In 1998, no analysis was possible, because too few trees produced a moderate to large acorn crop. Only density of female flowers was significantly associated with acorn production of moderately to highly reproductive trees in 1999. The effect of spatial scale was also investigated by conducting analyses with pollen producers counted in radii ranging from 30 m to 80 m. The association between number of pollen-producing neighbors and acorn production was strongest when neighborhood sizes of 60 m or larger were considered. Our results suggest that fragmentation and thinning of blue oak woodlands may reduce pollen availability and limit reproduction in this wind-pollinated species.

Loss of the Arabidopsis thaliana P4-ATPase ALA3 Reduces Adaptability to Temperature Stresses and Impairs Vegetative, Pollen, and Ovule Development

PubMed Central

McDowell, Stephen C.; López-Marqués, Rosa L.; Poulsen, Lisbeth R.; Palmgren, Michael G.; Harper, Jeffrey F.

2013-01-01

Members of the P4 subfamily of P-type ATPases are thought to help create asymmetry in lipid bilayers by flipping specific lipids between the leaflets of a membrane. This asymmetry is believed to be central to the formation of vesicles in the secretory and endocytic pathways. In Arabidopsis thaliana, a P4-ATPase associated with the trans-Golgi network (ALA3) was previously reported to be important for vegetative growth and reproductive success. Here we show that multiple phenotypes for ala3 knockouts are sensitive to growth conditions. For example, ala3 rosette size was observed to be dependent upon both temperature and soil, and varied between 40% and 80% that of wild-type under different conditions. We also demonstrate that ala3 mutants have reduced fecundity resulting from a combination of decreased ovule production and pollen tube growth defects. In-vitro pollen tube growth assays showed that ala3 pollen germinated ∼2 h slower than wild-type and had approximately 2-fold reductions in both maximal growth rate and overall length. In genetic crosses under conditions of hot days and cold nights, pollen fitness was reduced by at least 90-fold; from ∼18% transmission efficiency (unstressed) to less than 0.2% (stressed). Together, these results support a model in which ALA3 functions to modify endomembranes in multiple cell types, enabling structural changes, or signaling functions that are critical in plants for normal development and adaptation to varied growth environments. PMID:23667493

The European Survey on Adverse Systemic Reactions in Allergen Immunotherapy (EASSI): A paediatric assessment.

PubMed

Rodríguez Del Río, Pablo; Vidal, Carmen; Just, Jocelyne; Tabar, Ana I; Sanchez-Machin, Inmaculada; Eberle, Peter; Borja, Jesus; Bubel, Petra; Pfaar, Oliver; Demoly, Pascal; Calderón, Moises A

2017-02-01

Safety data on 'real-life' allergen immunotherapy (AIT) in children and adolescents is usually extrapolated from studies in adults. Patients aged 18 or under initiating aeroallergen AIT were evaluated in a prospective European survey. Patient profiles and systemic reactions (SRs) were recorded. Descriptive, univariate and multivariate analyses were used to identify risk factors for SRs. A total of 1563 patients (mean ± SD age: 11.7 ± 3.9 years; rhinitis: 93.7%; asthma: 61.5%; polysensitization: 62.5%) and 1578 courses of AIT were assessed. Single-allergen AIT was administered in 89.5% of cases (n = 1412; mites: 49%; grass pollen: 25.8%; tree pollen: 8.7%; Alternaria: 4.6%; dander: 0.8%; weed pollen: 0.6%). Subcutaneous AIT (SCIT) was used in 71.4% (n = 1127) of the treatments, including 574 (50.9%) with natural extracts. Sublingual AIT (SLIT) was used for the remaining 451 treatments (drops: 73.8%; tablets: 26.2%). The mean ± SD follow-up period was 12.9 ± 3.3 months. The estimated total number of doses was 19,669 for SCIT and 131,550 for SLIT. Twenty-four patients (1.53%) experienced 29 SRs. Respiratory (55.7%) and skin symptoms (37.9%) were most frequent. Anaphylaxis was diagnosed in 3 SRs (10.3%), and adrenaline was administered in 2 of these cases. In a univariate analysis, the risk of SRs was lower in mite-sensitized patients and higher in cases of pollen polysensitization (>3), grass pollen extracts and the use of natural extracts (vs. allergoids). In a real-life paediatric setting, AIT is safe. SRs are infrequent and generally not severe. Pollen polysensitization, grass pollen extracts and natural extracts (vs. allergoids) were risk factors for AIT-associated SRs. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An invasive plant alters pollinator-mediated phenotypic selection on a native congener.

PubMed

Beans, Carolyn M; Roach, Deborah A

2015-01-01

• Recent studies suggest that invasive plants compete reproductively with native plants by reducing the quantity or quality of pollinator visits. Although these studies have revealed ecological consequences of pollinator-mediated competition between invasive and native plants, the evolutionary outcomes of these interactions remain largely unexplored.• We studied the ecological and evolutionary impact of pollinator-mediated competition with an invasive jewelweed, Impatiens glandulifera, on a co-occurring native congener, I. capensis. Using a pollinator choice experiment, a hand pollination experiment, and a selection analysis, we addressed the following questions: (1) Do native pollinators show preference for the invasive or native jewelweed, and do they move between the two species? (2) Does invasive jewelweed pollen inhibit seed production in the native plant? (3) Does the invasive jewelweed alter phenotypic selection on the native plant's floral traits?• The pollinator choice experiment showed that pollinators strongly preferred the invasive jewelweed. The hand pollination experiment demonstrated that invasive pollen inhibited seed production in the native plant. The selection analysis showed that the presence of the invasive jewelweed altered phenotypic selection on corolla height in the native plant.• Invasive plants have the potential to alter phenotypic selection on floral traits in native plant populations. If native plants can evolve in response to this altered selection pressure, the evolution of floral traits may play an important role in permitting long-term coexistence of native and invasive plants. © 2015 Botanical Society of America, Inc.

A comparison of high-resolution pollen-inferred climate data from central Minnesota, USA, to 19th century US military fort climate data and tree-ring inferred climate reconstructions

NASA Astrophysics Data System (ADS)

St Jacques, J.; Cumming, B. F.; Sauchyn, D.; Vanstone, J. R.; Dickenson, J.; Smol, J. P.

2013-12-01

A vital component of paleoclimatology is the validation of paleoclimatological reconstructions. Unfortunately, there is scant instrumental data prior to the 20th century available for this. Hence, typically, we can only do long-term validation using other proxy-inferred climate reconstructions. Minnesota, USA, with its long military fort climate records beginning in 1820 and early dense network of climate stations, offers a rare opportunity for proxy validation. We compare a high-resolution (4-year), millennium-scale, pollen-inferred paleoclimate record derived from varved Lake Mina in central Minnesota to early military fort records and dendroclimatological records. When inferring a paleoclimate record from a pollen record, we rely upon the pollen-climate relationship being constant in time. However, massive human impacts have significantly altered vegetation; and the relationship between modern instrumental climate data and the modern pollen rain becomes altered from what it was in the past. In the Midwest, selective logging, fire suppression, deforestation and agriculture have strongly influenced the modern pollen rain since Euro-American settlement in the mid-1800s. We assess the signal distortion introduced by using the conventional method of modern post-settlement pollen and climate calibration sets to infer climate at Lake Mina from pre-settlement pollen data. Our first February and May temperature reconstructions are based on a pollen dataset contemporaneous with early settlement to which corresponding climate data from the earliest instrumental records has been added to produce a 'pre-settlement' calibration set. The second February and May temperature reconstructions are based on a conventional 'modern' pollen-climate dataset from core-top pollen samples and modern climate normals. The temperature reconstructions are then compared to the earliest instrumental records from Fort Snelling, Minnesota, and it is shown that the reconstructions based on the pre-settlement calibration set give much more credible reconstructions. We then compare the temperature reconstructions based upon the two calibration sets for AD 1116-2002. Significant signal flattening and bias exist when using the conventional modern pollen-climate calibration set rather than the pre-settlement pollen-climate calibration set, resulting in an overestimation of Little Ice Age monthly mean temperatures of 0.5-1.5 oC. Therefore, regional warming from anthropogenic global warming is significantly underestimated when using the conventional method of building pollen-climate calibration sets. We also compare the Lake Mina pollen-inferred effective moisture record to early 19th century climate data and to a four-century tree-ring inferred moisture reconstruction based upon sites in Minnesota and the Dakotas. This comparison shows that regional tree-ring reconstructions are biased towards dry conditions and record wet periods poorly relative to high-resolution pollen reconstructions, giving a false impression of regional aridity. It also suggests that varve chronologies should be based upon cross-dating to ensure a more accurate chronology.

Both population size and patch quality affect local extinctions and colonizations.

PubMed

Franzén, Markus; Nilsson, Sven G

2010-01-07

Currently, the habitat of many species is fragmented, resulting in small local populations with individuals occasionally dispersing between the remaining habitat patches. In a solitary bee metapopulation, extinction probability was related to both local bee population sizes and pollen resources measured as host plant population size. Patch size, on the other hand, had no additional predictive power. The turnover rate of local bee populations in 63 habitat patches over 4 years was high, with 72 extinction events and 31 colonization events, but the pollen plant population was stable with no extinctions or colonizations. Both pollen resources and bee populations had strong and independent effects on extinction probability, but connectivity was not of importance. Colonizations occurred more frequently within larger host plant populations. For metapopulation survival of the bee, large pollen plant populations are essential, independent of current bee population size.

Apitherapy products enhance the recovery of CCL4-induced hepatic damages in rats.

PubMed

Saral, Özlem; Yildiz, Oktay; Aliyazicioğlu, Rezzan; Yuluğ, Esin; Canpolat, Sinan; Öztürk, Ferhat; Kolayli, Sevgi

2016-01-05

Our objective was to identify the antioxidant properties of honeybee products from Turkey, chestnut honey, pollen, propolis, and royal jelly, and their hepatoprotective activity against CCl4-induced hepatic damage in rats. Animals were fed with honeybee products for 7 days following CCl4 injection. Development of liver damage and oxidative stress were monitored by measuring the activities of the enzymes alanine transaminase, aspartate transaminase, malondialdehyde, superoxide dismutase, and catalase. Antioxidant capacities of the bee products were identified using FRAP and DPPH assays, as well as by measuring total phenolic and flavonoid contents. The antioxidant activities of the honeybee products were highest in propolis, followed, in order, by pollen, honey, and royal jelly. Despite their different levels of antioxidant capacity, their roles in the prevention of liver damage induced by CCl4 were very similar, which can be explained through their bioavailability to the treated animals. Our results suggest that honey, propolis, pollen, and royal jelly significantly enhanced the healing of CCl4-induced liver damage, partially due to their antioxidant properties and bioavailability.

Abundance and Diversity of Wild Bees (Hymenoptera: Apoidea) Found in Lowbush Blueberry Growing Regions of Downeast Maine.

PubMed

Bushmann, Sara L; Drummond, Francis A

2015-08-01

Insect-mediated pollination is critical for lowbush blueberry (Ericaceae: Vaccinium angustifolium Aiton) fruit development. Past research shows a persistent presence of wild bees (Hymenoptera: Apoidea) providing pollination services even when commercial pollinators are present. We undertook the study to 1) provide a description of bee communities found in lowbush blueberry-growing regions, 2) identify field characteristics or farm management practices that influence those communities, 3) identify key wild bee pollinators that provide pollination services for the blueberry crop, and 4) identify non-crop plants found within the cropping system that provide forage for wild bees. During a 4-year period, we collected solitary and eusocial bees in over 40 fields during and after blueberry bloom, determining a management description for each field. We collected 4,474 solitary bees representing 124 species and 1,315 summer bumble bees representing nine species. No bumble bee species were previously unknown in Maine, yet we document seven solitary bee species new for the state. These include species of the genera Nomada, Lasioglossum, Calliopsis, and Augochloropsis. No field characteristic or farm management practice related to bee community structure, except bumble bee species richness was higher in certified organic fields. Pollen analysis determined scopal loads of 67-99% ericaceous pollen carried by five species of Andrena. Our data suggest two native ericaceous plants, Kalmia angustifolia L. and Gaylussacia baccata (Wangenheim), provide important alternative floral resources. We conclude that Maine blueberry croplands are populated with a species-rich bee community that fluctuates in time and space. We suggest growers develop and maintain wild bee forage and nest sites. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sexual Polyploidization in Medicago sativa L.: Impact on the Phenotype, Gene Transcription, and Genome Methylation

PubMed Central

Rosellini, Daniele; Ferradini, Nicoletta; Allegrucci, Stefano; Capomaccio, Stefano; Zago, Elisa Debora; Leonetti, Paola; Balech, Bachir; Aversano, Riccardo; Carputo, Domenico; Reale, Lara; Veronesi, Fabio

2016-01-01

Polyploidization as the consequence of 2n gamete formation is a prominent mechanism in plant evolution. Studying its effects on the genome, and on genome expression, has both basic and applied interest. We crossed two diploid (2n = 2x = 16) Medicago sativa plants, a subsp. falcata seed parent, and a coerulea × falcata pollen parent that form a mixture of n and 2n eggs and pollen, respectively. Such a cross produced full-sib diploid and tetraploid (2n = 4x = 32) hybrids, the latter being the result of bilateral sexual polyploidization (BSP). These unique materials allowed us to investigate the effects of BSP, and to separate the effect of intraspecific hybridization from those of polyploidization by comparing 2x with 4x full sib progeny plants. Simple sequence repeat marker segregation demonstrated tetrasomic inheritance for all chromosomes but one, demonstrating that these neotetraploids are true autotetraploids. BSP brought about increased biomass, earlier flowering, higher seed set and weight, and larger leaves with larger cells. Microarray analyses with M. truncatula gene chips showed that several hundred genes, related to diverse metabolic functions, changed their expression level as a consequence of polyploidization. In addition, cytosine methylation increased in 2x, but not in 4x, hybrids. Our results indicate that sexual polyploidization induces significant transcriptional novelty, possibly mediated in part by DNA methylation, and phenotypic novelty that could underpin improved adaptation and reproductive success of tetraploid M. sativa with respect to its diploid progenitor. These polyploidy-induced changes may have promoted the adoption of tetraploid alfalfa in agriculture. PMID:26858330

Sexual Polyploidization in Medicago sativa L.: Impact on the Phenotype, Gene Transcription, and Genome Methylation.

PubMed

Rosellini, Daniele; Ferradini, Nicoletta; Allegrucci, Stefano; Capomaccio, Stefano; Zago, Elisa Debora; Leonetti, Paola; Balech, Bachir; Aversano, Riccardo; Carputo, Domenico; Reale, Lara; Veronesi, Fabio

2016-04-07

Polyploidization as the consequence of 2n gamete formation is a prominent mechanism in plant evolution. Studying its effects on the genome, and on genome expression, has both basic and applied interest. We crossed two diploid (2n = 2x = 16) Medicago sativa plants, a subsp. falcata seed parent, and a coerulea × falcata pollen parent that form a mixture of n and 2n eggs and pollen, respectively. Such a cross produced full-sib diploid and tetraploid (2n = 4x = 32) hybrids, the latter being the result of bilateral sexual polyploidization (BSP). These unique materials allowed us to investigate the effects of BSP, and to separate the effect of intraspecific hybridization from those of polyploidization by comparing 2x with 4x full sib progeny plants. Simple sequence repeat marker segregation demonstrated tetrasomic inheritance for all chromosomes but one, demonstrating that these neotetraploids are true autotetraploids. BSP brought about increased biomass, earlier flowering, higher seed set and weight, and larger leaves with larger cells. Microarray analyses with M. truncatula gene chips showed that several hundred genes, related to diverse metabolic functions, changed their expression level as a consequence of polyploidization. In addition, cytosine methylation increased in 2x, but not in 4x, hybrids. Our results indicate that sexual polyploidization induces significant transcriptional novelty, possibly mediated in part by DNA methylation, and phenotypic novelty that could underpin improved adaptation and reproductive success of tetraploid M. sativa with respect to its diploid progenitor. These polyploidy-induced changes may have promoted the adoption of tetraploid alfalfa in agriculture. Copyright © 2016 Rosellini et al.

State and Spectral Properties of Chloride Oscillations in Pollen

PubMed Central

Zonia, Laura; Feijó, José A.

2003-01-01

Pollen tube growth is a dynamic system expressing a number of oscillating circuits. Our recent work identified a new circuit, oscillatory efflux of Cl− anion from the pollen tube apex. Cl− efflux is the first ion signal found to be coupled in phase with growth oscillations. Functional analyses indicate an active role for Cl− flux in pollen tube growth. In this report the dynamical properties of Cl− efflux are examined. Phase space analysis demonstrates that the system trajectory converges on a limit cycle. Fourier analysis reveals that two harmonic frequencies characterize normal growth. Cl− efflux is inhibited by the channel blocker DIDS, is stimulated by hypoosmotic treatment, and is antagonized by the signal encoded in inositol 3,4,5,6-tetrakisphosphate. These perturbations induce transitions of the limit cycle to new metastable states or cause system collapse to a static attractor centered near the origin. These perturbations also transform the spectral profile, inducing subharmonic frequencies, transitions to period doubling and tripling, superharmonic resonance, and chaos. These results indicate that Cl− signals in pollen tubes display features that are characteristic of active oscillators that carry frequency-encoded information. A reaction network of the Cl− oscillator coupled to two nonlinear feedback circuits that may drive pollen tube growth oscillations is considered. PMID:12547818

[Sensitization to pollens of Oleaceae family in a group of patients from Mexico City].

PubMed

Morfín-Maciel, Blanca María; Flores, Iveth; Rosas-Alvarado, Alejandro; Bautista, Maura; López-López, Jorge Roberto

2009-01-01

In Mexico City, where the Olive trees are scarce, the Oleaceae family has been recognized as one of the most important causes of pollen allergy, possibly related to cross-reactivity with other pollens of the Oleaceae family, as Fraxinus excelsior, Ligustrum vulgaris and Osmanthus americanus. To know the prevalence of sensitization to the Oleaceae family in Mexico City, cross-reactivity, as well as concurrent sensitizations, and vegetables and fruits associated to oral allergy syndrome (OAS). A prospective, longitudinal study was carried out during two months, among patients who attended the outpatient allergy clinic of the General Hospital of Mexico with symptoms suggestive of respiratory allergy. A questionnaire to search OAS was used, and skin Prick tests to pollens were performed. Among 279 patients, 164 (58.8%) had respiratory allergy and positive skin prick test (SPT) to pollens. Olea europaea had the highest prevalence of SPT reactivity (52.4%), followed by Fraxinus excelsior (43.3%), Ligustrum vulgaris (36.6%) and Osmanthus americanus (15.9%). There were OAS in 53.5%, 50.7%, 50% and 53.8%, respectively, mainly related to peach, apple, kiwi, pear and banana. Olive monosensitization was found in 5.5%. In this study, Olea europaea had the highest prevalence of positive reactivity to pollens in Mexico City, then its sensitization must be determined routinely.

Archaeological Investigation in the Perry Lake Project Area, Northeastern Kansas National Register Evaluation of 17 Sites

DTIC Science & Technology

1989-01-01

Muscotah and Arrington marshes reveal the presence of open vegetation, with some pine, spruce, and birch trees and local stands of alder and willow...1977). Zone 4 pollen frequency curves demonstrate the dynamic nature of the prairie-forest ecotone. In zone 4a, grasses and deciduous trees are both...ecotone. Trees disappeared from the uplands and low values of some types of arboreal pollen suggest that the Delaware River floodplain "dried out over

Quantification of Pla or 3, a Platanus orientalis Allergen, Grown under Different Environmental Conditions, by Sandwich ELISA.

PubMed

Sedghy, Farnaz; Sankian, Mojtaba; Moghadam, Maliheh; Varasteh, Abdol-Reza

2016-10-01

Platanus species are widely cultured around the world and considered an important cause of allergic reactions. In the present study, we developed a sandwich ELISA to quantify Pla or 3 allergen in P. orientalis pollen extracts grown near high-traffic roads and compared it to pollen extracts collected from rural areas as control. Pollen samples were collected from three polluted and two unpolluted sites in Mashhad, northeast Iran. Recombinant Pla or 3 was expressed and used for polyclonal antibody production in rabbit. A sandwich ELISA was developed and validated to quantify Pla or 3 levels in pollen extracts from the different sites. The coefficients of variation (CVs) for the intra- and inter- day assays were less than 5 and 18%, respectively. The working range of the standard curve was between 0.1 and 25 ng/ml, with the detection limit being 0.037 ng/ml. The recovery percentage was 88-106.4% at working concentrations from 0.31 to 26.5 ng/ml. Pla or 3 levels were significantly greater in pollens grown near high-traffic roads than in those grown in rural regions (p < 0.0001). A sandwich ELISA was developed and validated to quantify Pla or 3 in pollen extracts. Using this validated ELISA, we showed a substantial difference between the amounts of Pla or 3 in pollens grown in different environments. This finding should be considered in developing public policies to reduce traffic pollution, which leads to reduced allergic reactions in atopic subjects.

Pollen flow in fragmented landscapes maintains genetic diversity following stand-replacing disturbance in a neotropical pioneer tree, Vochysia ferruginea Mart.

PubMed

Davies, S J; Cavers, S; Finegan, B; White, A; Breed, M F; Lowe, A J

2015-08-01

In forests with gap disturbance regimes, pioneer tree regeneration is typically abundant following stand-replacing disturbances, whether natural or anthropogenic. Differences in pioneer tree density linked to disturbance regime can influence pollinator behaviour and impact on mating patterns and genetic diversity of pioneer populations. Such mating pattern shifts can manifest as higher selfing rates and lower pollen diversity in old growth forest populations. In secondary forest, where more closely related pollen donors occur, an increase in biparental inbreeding is a potential problem. Here, we investigate the consequences of secondary forest colonisation on the mating patterns and genetic diversity of open-pollinated progeny arrays for the long-lived, self-compatible pioneer tree, Vochysia ferruginea, at two Costa Rican sites. Five microsatellite loci were screened across adult and seed cohorts from old growth forest with lower density, secondary forest with higher density, and isolated individual trees in pasture. Progeny from both old growth and secondary forest contexts were predominantly outcrossed (tm=1.00) and experienced low levels of biparental inbreeding (tm-ts=0.00-0.04). In contrast to predictions, our results indicated that the mating patterns of V. ferruginea are relatively robust to density differences between old growth and secondary forest stands. In addition, we observed that pollen-mediated gene flow possibly maintained the genetic diversity of open-pollinated progeny arrays in stands of secondary forest adults. As part of a natural resource management strategy, we suggest that primary forest remnants should be prioritised for conservation to promote restoration of genetic diversity during forest regeneration.

Occupational asthma induced by garlic dust.

PubMed

Añibarro, B; Fontela, J L; De La Hoz, F

1997-12-01

Garlic dust has not been a frequently encountered cause of IgE-mediated disease. We report on 12 patients (all of them garlic workers) with the clinical criteria for occupational asthma. Skin prick tests and serum-specific IgE determinations were performed with common inhalants, garlic, and other members of the Liliaceae family (onion, leek, and asparagus). Bronchial challenge test with garlic powder was performed in all patients. Garlic and onion extract proteins were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Immunoblot and IgE immunoblot inhibition analyses were performed with patients' sera on extracts of garlic, onion, and pollens of Phleum pratense and Chenopodium album. Garlic sensitization was demonstrated by bronchial challenge test in seven patients (group 1) and ruled out in the remaining five (group 2). Clinical data were similar in both groups. The patients with garlic allergy had a mean age of 27 years, and all of them had pollen allergy; sensitization to other members of the Liliaceae family was also common. Electrophoresis of garlic extract revealed two major protein bands at approximately 12 and 54 kd. During IgE immunoblotting, the pool of sera reacted with garlic proteins mainly at 54 kd. Preincubation with onion, Phleum, and Chenopodium partially abolished the IgE binding to several allergens of garlic. We report on seven patients in whom an occupational garlic allergy was demonstrated. Garlic allergy is relatively rare but seems to affect young subjects with pollen allergy, and sensitization to other members of the Liliaceae family is common. The results of this study confirm the presence of some structurally similar allergens in garlic, onion, and certain pollens.

Insights into MIS 3 and 4 climate in the Alps from the Baumkirchen paleo-lake site: Results of pollen analysis

NASA Astrophysics Data System (ADS)

Barrett, Samuel; Drescher-Schneider, Ruth; Starnberger, Reinhard; Spötl, Christoph

2016-04-01

The well-known Baumkirchen site of western Austria has recently been the focus of a renewed research effort. New drilling has greatly extended the length of the known lacustrine sequence to over 250 m. Luminescence dating has corroborated the late MIS 3 radiocarbon dates for the upper part of the sequence and revealed two lake phases: the upper extending from late MIS 3 back to mid MIS 3, and the lower covering late MIS 4 or early MIS 3 back possibly as far as MIS 5a. X-ray fluorescence core scanning analysis confirmed the presence of two phases which have different geochemical signals, and provided a chemistry-based stratigraphy in the visually monotonous sediments. In these uniform sediments, the only clear indication of climatic conditions from the sediments themselves is a short sequence of ice-rafted debris corresponding to the end of MIS 4. However, given their age and location within the Alps, these sediments provide an important archive of Alpine climate in the last glacial cycle. We present new results from pollen analysis and discuss them in the context of previously reported findings. Due to high sedimentation rates, pollen counts were very low. However, two stadials and two interstadials were identified. The entire lower lake phase corresponding to MIS 4 was identified as a stadial, being characterised by a very low total pollen concentrations, a dominance of herb over tree pollen and significant reworking of pre-Quaternary forms and wood fragments. The upper lake phase contains two interstadials split by an intervening stadial. The interstadials are characterised by higher total pollen concentrations and proportion of woody species including the sporadic presence of relatively warm climate species with the upper of the two appearing better developed with these indicators more strongly expressed. This upper interstadial corresponds to the location of well dated plant remains putting its age around 35 ka cal BP, strongly suggesting a correlation to Greenland interstadial 7, while the correspondence of the lower interstadial is uncertain. Overall, the vegetation of the central Inn Valley during MIS 3 and 4 was dominated by steppe-like open-vegetation (consistent with earlier work from the upper part of the sequence) with tree stands (but not forests) establishing themselves during the interstadials.

The role of flower pollen extract in managing patients affected by chronic prostatitis/chronic pelvic pain syndrome: a comprehensive analysis of all published clinical trials.

PubMed

Cai, Tommaso; Verze, Paolo; La Rocca, Roberto; Anceschi, Umberto; De Nunzio, Cosimo; Mirone, Vincenzo

2017-04-21

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is still a challenge to manage for all physicians. We feel that a summary of the current literature and a systematic review to evaluate the therapeutic efficacy of flower pollen extract would be helpful for physicians who are considering a phytotherapeutic approach to treating patients with CP/CPPS. A comprehensive search of the PubMed and Embase databases up to June 2016 was performed. This comprehensive analysis included both pre-clinical and clinical trials on the role of flower pollen extract in CP/CPPS patients. Moreover, a meta-analysis of available randomized controlled trials (RCTs) was performed. The NIH Chronic Prostatitis Symptom Index (NIH-CPSI) and Quality of Life related questionnaires (QoL) were the most commonly used tools to evaluate the therapeutic efficacy of pollen extract. Pre-clinical studies demonstrated the anti-inflammatory and anti-proliferative role of pollen extract. 6 clinical, non-controlled studies including 206 patients, and 4 RCTs including 384 patients were conducted. The mean response rate in non-controlled studies was 83.6% (62.2%-96.0%). The meta-analysis revealed that flower pollen extract could significantly improve patients' quality of life [OR 0.52 (0.34-.0.81); p = 0.02]. No significant adverse events were reported. Most of these studies presented encouraging results in terms of variations in NIH-CPSI and QoL scores. These studies suggest that the use of flower pollen extract for the management of CP/CPPS patients is beneficial. Future publications of robust evidence from additional RCTs and longer-term follow-up would provide more support encouraging the use of flower pollen extracts for CP/CPPS patients.

Grass Pollen Affects Survival and Development of Larval Anopheles arabiensis (Diptera: Culicidae).

PubMed

Asmare, Yelfwagash; Hopkins, Richard J; Tekie, Habte; Hill, Sharon R; Ignell, Rickard

2017-09-01

Nutrients in breeding sites are critical for the survival and development of malaria mosquitoes, having a direct impact on vectorial capacity. Yet, there is a limited understanding about the natural larval diet and its impact on the individual fitness of mosquitoes. Recent studies have shown that gravid Anopheles arabiensis Patton (Diptera: Culicidae) are attracted by and oviposit in grass-associated habitats. The pollen provided by these grasses is a potential source of nutrients for the larvae. Here, we assess the effect of Typha latifolia L. (Poales: Typhaceae), Echinochloa pyramidalis Lamarck, Pennisetum setaceum Forsskål, and Zea mays L. pollen on larval survival and rate of development in An. arabiensis under laboratory conditions. In addition, we characterize the carbon to nitrogen ratio and the size of pollen grains as a measure of diet quality. Carbon-rich pollen with a small grain size (T. latifolia and P. setaceum; 9.7 ± 0.3 × 103 and 5.5 ± 0.2 × 104 µm3, respectively) resulted in enhanced rates of development of An. arabiensis. In contrast, the larva fed on the nitrogen-rich control diet (TetraMin) was slower to develop, but demonstrated the highest larval survival. Larvae fed on carbon-rich and large-grained Z. mays pollen (4.1 ± 0.2 × 105 µm3) survived at similar levels as those fed on the control diet and also took a longer time to develop compared with larvae fed on the other pollens. While males and females did not appear to develop differently on the different pollen diets, males consistently emerged faster than their female counterparts. These results are discussed in relation to integrated vector management. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Acidic fog and temperature effects on stigmatic receptivity in two birch species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, R.N.; Cox, R.M.

Factorial assays were performed to determine the effects of simulated acid fog (SAF) and temperature on stigmatic receptivity in two birch species. Excised reproductive branches were sampled from representative individuals of mountain paper birch (Betula cordifolia Regel.) and paper birch (Betula papyrifera Marsh.) in populations adjacent to the Bay of Fundy, New Brunswick, Canada. Since 1979 these trees have exhibited branch dieback in association with abnormal foliar browning symptoms. This browning has been linked with acidity and nitrate deposited by fog, which is frequent in the area. In general, experimental results indicated that pollen germination increased with temperature, but pHmore » effects were less obvious. Similarly, pollen tube growth responded positively to temperature and was little affected by fog acidity. ANOVA tests indicated a significant difference (P < 0.05) between species in their pollen germination response only at 12{degrees}C, and not at the other three temperatures tested. For pollen tube growth, significant differences between species (P < 0.05) were demonstrated at 12 and 22{degrees}C. A significant pH effect was demonstrated at 27{degrees}C for germination, while pH effects on tube growth were significant at 27 and 12{degrees}C (P < 0.01). A response surface regression analysis indicated that acidity significantly affected pollen germination in mountain paper birch (P < 0.001) but not in paper birch. Temperature was not a significant factor for in vivo pollen germination in either species. For pollen tube growth, however, temperature was more important than pH and produced highly significant effects in both species (P < 0.001). Acidity was also a significant factor in pollen tube growth for paper birch. 39 refs., 4 figs., 3 tabs.« less

Ultra-short-course booster is effective in recurrent grass pollen-induced allergic rhinoconjunctivitis.

PubMed

Pfaar, O; Lang, S; Pieper-Fürst, U; Astvatsatourov, A; Gerich, F; Klimek, L; Kramer, M F; Reydelet, Y; Shah-Hosseini, K; Mösges, R

2018-01-01

A relevant proportion of allergic rhinoconjunctivitis (ARC) patients experience recurrent symptoms after successfully completing allergen immunotherapy (AIT). This prospective, controlled, noninterventional study used internationally standardized instruments to determine the clinical effects of a preseasonal, ultra-short-course booster AIT on clinical outcome parameters. This two-arm study included patients aged ≥12 years with recurrent grass pollen-induced seasonal AR who had completed a successful course of any grass pollen AIT at least 5 years before enrolment. Overall, 56 patients received one preseasonal short-course booster AIT using tyrosine-absorbed grass pollen allergoids containing the adjuvant monophosphoryl lipid A (MPL ® ); 51 control patients received symptomatic medication. The combined symptom and medication score (CSMS) was recorded in the (peak) grass pollen season. Furthermore, concomitant (antiallergic) medication use, the patients' state of health, Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) results and safety/tolerability of the treatment were assessed. The CSMS in the peak grass pollen season was significantly lower in the booster AIT group (Δ=38.4%, P<.01). Moreover, significantly more patients in this group used no concomitant antiallergic medication throughout the peak grass pollen season. Twice as many patients in the booster AIT group as in the control group reported having a better state of health than in the preceding season. MiniRQLQ results showed significant differences favouring the booster AIT. The booster AIT was generally well tolerated, with only two patients reporting mild, grade 1 systemic adverse events. Booster AIT using tyrosine-absorbed allergoids containing the adjuvant MPL ® effectively prevents re-occurrence of symptoms in patients with grass pollen-induced ARC. © 2017 The Authors. Allergy Published by John Wiley & Sons Ltd.

Masting in ponderosa pine: comparisons of pollen and seed over space and time.

PubMed

Mooney, Kailen A; Linhart, Yan B; Snyder, Marc A

2011-03-01

Many plant species exhibit variable and synchronized reproduction, or masting, but less is known of the spatial scale of synchrony, effects of climate, or differences between patterns of pollen and seed production. We monitored pollen and seed cone production for seven Pinus ponderosa populations (607 trees) separated by up to 28 km and 1,350 m in elevation in Boulder County, Colorado, USA for periods of 4-31 years for a mean per site of 8.7 years for pollen and 12.1 for seed cone production. We also analyzed climate data and a published dataset on 21 years of seed production for an eighth population (Manitou) 100 km away. Individual trees showed high inter-annual variation in reproduction. Synchrony was high within populations, but quickly became asynchronous among populations with a combination of increasing distance and elevational difference. Inter-annual variation in temperature and precipitation had differing influences on seed production for Boulder County and Manitou. We speculate that geographically variable effects of climate on reproduction arise from environmental heterogeneity and population genetic differentiation, which in turn result in localized synchrony. Although individual pines produce pollen and seed, only one-third of the covariation within trees was shared. As compared to seed cones, pollen had lower inter-annual variation at the level of the individual tree and was more synchronous. However, pollen and seed production were similar with respect to inter-annual variation at the population level, spatial scales of synchrony and associations with climate. Our results show that strong masting can occur at a localized scale, and that reproductive patterns can differ between pollen and seed cone production in a hermaphroditic plant.

Is pollen removal or seed set favoured by flower longevity in a hummingbird-pollinated Salvia species?

PubMed Central

Aximoff, Izar Araujo; Freitas, Leandro

2010-01-01

Background and Aims The period between the beginning of anthesis and flower senescence modulates the transport of pollen by pollinators among conspecific flowers, and its length may therefore influence reproductive success. This study evaluated whether floral longevity favours pollen removal from the anthers over fecundity (seed set) in an ornithophilous species that does not undergo pollen limitation. Methods Field investigations were conducted on floral longevity, nectar production, pollinator behaviour, and variations in fruit set (FS), mean number of seeds per fruit (MSF) and pollen removal by hummingbirds (PR) during the anthesis of Salvia sellowiana in south-east Brazil. Key Results Anthesis of flowers exposed to pollinators lasted 4 d, as well as on flowers with pollen removed from the anthers or deposited on the stigma. The longevity of bagged flowers was significantly higher (approx. 9 d). FS and PR reached 87·2 and 90 %, respectively, in natural conditions. PR increased gradually over the period of anthesis; however, FS and MSF reached their maxima in the first hours of anthesis. Nectar production was continuous, but the secretion rate was reduced after pollination. The removal of nectar from non-pollinated flowers stimulated its production. Conclusions The longevity of anthesis in S. sellowiana seems to be related to the mechanism of gradual dispensing of pollen, resulting in greater male reproductive success. This is in agreement with the pollen-donation hypothesis. The small number of ovules (four) of S. sellowiana and the high frequency and the foraging mode of its pollinators may favour the selection for floral longevity driven by male fitness in this system. PMID:20622254

Honey bees preferentially consume freshly-stored pollen

USDA-ARS?s Scientific Manuscript database

Honey bees collect and store pollen in cells in a preserved form known as stored pollen, or beebread. To preserve pollen, bees add nectar and honey to collected pollen to form stored pollen. Bees eat stored pollen from a wide selection of pollen cells that have been stored for different lengths of...

Novel small molecule modulators of plant growth and development identified by high-content screening with plant pollen.

PubMed

Chuprov-Netochin, Roman; Neskorodov, Yaroslav; Marusich, Elena; Mishutkina, Yana; Volynchuk, Polina; Leonov, Sergey; Skryabin, Konstantin; Ivashenko, Andrey; Palme, Klaus; Touraev, Alisher

2016-09-06

Small synthetic molecules provide valuable tools to agricultural biotechnology to circumvent the need for genetic engineering and provide unique benefits to modulate plant growth and development. We developed a method to explore molecular mechanisms of plant growth by high-throughput phenotypic screening of haploid populations of pollen cells. These cells rapidly germinate to develop pollen tubes. Compounds acting as growth inhibitors or stimulators of pollen tube growth are identified in a screen lasting not longer than 8 h high-lighting the potential broad applicability of this assay to prioritize chemicals for future mechanism focused investigations in plants. We identified 65 chemical compounds that influenced pollen development. We demonstrated the usefulness of the identified compounds as promotors or inhibitors of tobacco and Arabidopsis thaliana seed growth. When 7 days old seedlings were grown in the presence of these chemicals twenty two of these compounds caused a reduction in Arabidopsis root length in the range from 4.76 to 49.20 % when compared to controls grown in the absence of the chemicals. Two of the chemicals sharing structural homology with thiazolidines stimulated root growth and increased root length by 129.23 and 119.09 %, respectively. The pollen tube growth stimulating compound (S-02) belongs to benzazepin-type chemicals and increased Arabidopsis root length by 126.24 %. In this study we demonstrate the usefulness of plant pollen tube based assay for screening small chemical compound libraries for new biologically active compounds. The pollen tubes represent an ultra-rapid screening tool with which even large compound libraries can be analyzed in very short time intervals. The broadly applicable high-throughput protocol is suitable for automated phenotypic screening of germinating pollen resulting in combination with seed germination assays in identification of plant growth inhibitors and stimulators.

Dose-response relationship of a new Timothy grass pollen allergoid in comparison with a 6-grass pollen allergoid.

PubMed

Pfaar, O; Hohlfeld, J M; Al-Kadah, B; Hauswald, B; Homey, B; Hunzelmann, N; Schliemann, S; Velling, P; Worm, M; Klimek, L

2017-11-01

Subcutaneous allergen immunotherapy with grass pollen allergoids has been proven to be effective and safe in the treatment of patients with allergic rhinoconjunctivitis. Based on the extensive cross-reactivity among Pooideae species, it has been suggested that grass pollen extracts could be prepared from a single species, rather than from a multiple species mixture. To find the optimal dose of a Phleum pratense (P. pratense) allergoid preparation and compare its efficacy and safety to a 6-grass pollen allergoid preparation. In this double-blind, placebo-controlled study (EudraCT: 2011-000674-58), three doses of P. pratense allergoid (1800 therapeutic units (TU), standard-dose 6000 TU and 18 000 TU) were compared with placebo and the marketed 6-grass pollen allergoid (6000 TU). In a pre-seasonal dosing regimen, 102 patients were randomized to five treatment groups and received nine subcutaneous injections. The primary efficacy endpoint was the change in weal size (late-phase reaction [LPR]) in response to the intracutaneous testing (ICT) before and after treatment, comparing the active allergoids to placebo. Secondary outcomes were the change in Total Nasal Symptom Score (TNSS) assessed in the allergen exposure chamber (AEC), the changes in P. pratense-serum-specific IgG 4 and the incidence of adverse events (AEs). All three doses of the P. pratense and the 6-grass pollen allergoid preparations were significantly superior to placebo for the primary outcome, whereas there were no significant differences in the change in TNSS. Compared to the standard-dose, the high-dose of P. pratense did not produce any additional significant benefit, but showed a slight increase in AEs. Yet this increase in AEs was lower than for the 6-grass pollen preparation. The standard-dose of the new P. pratense allergoid was comparable to the marketed 6-grass pollen preparation at equal dose for the parameters measured. © 2017 The Authors. Clinical & Experimental Allergy Published by John Wiley & Sons Ltd.

Discriminating styles (DS) and pollen-mediated pseudo-self-compatibility (PMPSC) in Nemesia strumosa Benth. : Part 1: Characteristics and inheritance of DS.

PubMed

Robacker, C D; Ascher, P D

1981-09-01

Nemesia strumosa plants were discovered which had styles capable of discriminating among incompatible pollen tubes from different pollinators, allowing growth of some but not others. All but 3 of 26 families tested had at least some members with discriminating styles (DS). Presence and level of DS was independent of S genotype. Plants with pseudo-self-compatiblity (PSC) levels greater than 10% had the trait, though many plants with strong DS had PSC levels less than 10%. Self pollination of highly DS plants produced mostly DS offspring, but of differing sensitivities. Some progenies from crosses between a family of highly DS plants and unrelated, probably low DS plants segregated half DS and half non-DS, while others consisted of mostly DS or mostly non-DS. The DS phenomenon is probably caused by PSC genes.

Migratory Bee Hive Transportation Contributes Insignificantly to Transgenic Pollen Movement Between Spatially Isolated Alfalfa Seed Fields.

PubMed

Boyle, Natalie K; Kesoju, Sandya R; Greene, Stephanie L; Martin, Ruth C; Walsh, Douglas B

2017-02-01

Contracted commercial beekeeping operations provide an essential pollination service to many agricultural systems worldwide. Increased use of genetically engineered crops in agriculture has raised concerns over pollinator-mediated gene flow between transgenic and conventional agricultural varieties. This study evaluated whether contracted migratory beekeeping practices influence transgenic pollen flow among spatially isolated alfalfa fields. Twelve honey bee (Apis mellifera L.) colonies were permitted to forage on transgenic alfalfa blossoms for 1 wk in Touchet, WA. The hives were then transported 112 km to caged conventional alfalfa plots following one and two nights of isolation (8 and 32 h, respectively) from the transgenic source. Alfalfa seed harvested from the conventional plots was assessed for the presence of the transgene using a new seedling germination assay. We found that 8 h of isolation from a transgenic alfalfa source virtually eliminated the incidence of cross-pollination between the two varieties.

Upper Paleocene and lowermost Eocene angiosperm pollen biostratigraphy of the eastern Gulf Coast and Virginia

USGS Publications Warehouse

Frederiksen, N.O.

1998-01-01

Strata comprising most of the upper Paleocene in eastern North America are divided into two new pollen zones, the Carya and Platycarya platycaryoides Interval Zones. Pollen data have proven to be important for correlations between Alabama-western Georgia and eastern Mississippi and between the eastern Gulf Coast and Virginia. Migration of tropical plant taxa from the Caribbean to the Gulf Coast began at least 4 m.y. before the end of the Paleocene. The Terminal Paleocene Extinction Event, accompanied by a distinct pulse of plant immigration from Europe, began several hundred thousand years before the end of the Paleocene.

Lidar measurements of boundary layer depolarization and CCSEM-EDX compositional analysis of airborne particles on collocated passive samplers throughout the forest canopy during the 2016 airborne pollen season at UMBS, Pellston, MI

NASA Astrophysics Data System (ADS)

Wozniak, M. C.; Steiner, A.; Ault, A. P.; Kort, E. A.; Lersch, T.; Casuccio, G.

2017-12-01

Observations of airborne pollen are typically made with volumetric samplers that obtain a time-averaged pollen concentration at a single point. While spatial variations in surface pollen concentrations may be known with these samplers given multiple sampling sites, real-time boundary layer transport of pollen grains cannot be determined except by particle dispersion or tracer transport models. Recently, light detection and ranging (lidar) techniques, such as depolarization, have been used to measure pollen transport and optical properties throughout the boundary layer over time. Here, we use a ground-based micro-pulse lidar (MPL) to observe boundary layer vertical profiles before, during and after the peak anemophilous (wind-driven) pollen season. The lidar depolarization ratio is measured in tandem with the normalized R-squared backscatter (NRB) intensity to determine the contribution of aspherical particles to the scatterers present throughout the boundary layer. Measurements are taken from April 15 - July 12, 2016 at the University of Michigan Biological Station (UMBS) PROPHET outdoor research lab and tower within a largely forested region. UMBS is dominated by Acer rubrum, Betula papyrifera, Pinus resinosa, Quercus rubra and Pinus strobus, all of which began flowering on 4/19, 5/3, 5/25, 5/25 and 6/14, respectively. Temperature, relative humidity and wind speed measured on site determine daytime conditions conducive to pollen dispersion from flowers. Lidar depolarization ratios between 0.08-0.14 and higher are observed in the daytime boundary layer on days shortly after the flowering dates of the aforementioned species, elevated above the background level of 0.06 or less. Lidar observations are supplemented with aerosol compositional analysis determined by computer-controlled scanning electron microscopy and energy-dispersive X-ray spectroscopy (CCSEM-EDX) on passive sampler data from below, within and above the forest canopy at PROPHET tower. Particles are separated into the following classes based on composition: pollen, non-pollen biological, soot and other (including mineral dust). Particle shape parameters such as aspect ratio and circularity determined from CCSEM images to estimate how aspherical, and thus how strongly depolarizing, each particle class is.

A transcriptional dynamic network during Arabidopsis thaliana pollen development.

PubMed

Wang, Jigang; Qiu, Xiaojie; Li, Yuhua; Deng, Youping; Shi, Tieliu

2011-01-01

To understand transcriptional regulatory networks (TRNs), especially the coordinated dynamic regulation between transcription factors (TFs) and their corresponding target genes during development, computational approaches would represent significant advances in the genome-wide expression analysis. The major challenges for the experiments include monitoring the time-specific TFs' activities and identifying the dynamic regulatory relationships between TFs and their target genes, both of which are currently not yet available at the large scale. However, various methods have been proposed to computationally estimate those activities and regulations. During the past decade, significant progresses have been made towards understanding pollen development at each development stage under the molecular level, yet the regulatory mechanisms that control the dynamic pollen development processes remain largely unknown. Here, we adopt Networks Component Analysis (NCA) to identify TF activities over time course, and infer their regulatory relationships based on the coexpression of TFs and their target genes during pollen development. We carried out meta-analysis by integrating several sets of gene expression data related to Arabidopsis thaliana pollen development (stages range from UNM, BCP, TCP, HP to 0.5 hr pollen tube and 4 hr pollen tube). We constructed a regulatory network, including 19 TFs, 101 target genes and 319 regulatory interactions. The computationally estimated TF activities were well correlated to their coordinated genes' expressions during the development process. We clustered the expression of their target genes in the context of regulatory influences, and inferred new regulatory relationships between those TFs and their target genes, such as transcription factor WRKY34, which was identified that specifically expressed in pollen, and regulated several new target genes. Our finding facilitates the interpretation of the expression patterns with more biological relevancy, since the clusters corresponding to the activity of specific TF or the combination of TFs suggest the coordinated regulation of TFs to their target genes. Through integrating different resources, we constructed a dynamic regulatory network of Arabidopsis thaliana during pollen development with gene coexpression and NCA. The network illustrated the relationships between the TFs' activities and their target genes' expression, as well as the interactions between TFs, which provide new insight into the molecular mechanisms that control the pollen development.

Climate Change and Future Pollen Allergy in Europe.

PubMed

Lake, Iain R; Jones, Natalia R; Agnew, Maureen; Goodess, Clare M; Giorgi, Filippo; Hamaoui-Laguel, Lynda; Semenov, Mikhail A; Solomon, Fabien; Storkey, Jonathan; Vautard, Robert; Epstein, Michelle M

2017-03-01

Globally, pollen allergy is a major public health problem, but a fundamental unknown is the likely impact of climate change. To our knowledge, this is the first study to quantify the consequences of climate change upon pollen allergy in humans. We produced quantitative estimates of the potential impact of climate change upon pollen allergy in humans, focusing upon common ragweed ( Ambrosia artemisiifolia ) in Europe. A process-based model estimated the change in ragweed's range under climate change. A second model simulated current and future ragweed pollen levels. These findings were translated into health burdens using a dose-response curve generated from a systematic review and from current and future population data. Models considered two different suites of regional climate/pollen models, two greenhouse gas emissions scenarios [Representative Concentration Pathways (RCPs) 4.5 and 8.5], and three different plant invasion scenarios. Our primary estimates indicated that sensitization to ragweed will more than double in Europe, from 33 to 77 million people, by 2041-2060. According to our projections, sensitization will increase in countries with an existing ragweed problem (e.g., Hungary, the Balkans), but the greatest proportional increases will occur where sensitization is uncommon (e.g., Germany, Poland, France). Higher pollen concentrations and a longer pollen season may also increase the severity of symptoms. Our model projections were driven predominantly by changes in climate (66%) but were also influenced by current trends in the spread of this invasive plant species. Assumptions about the rate at which ragweed spreads throughout Europe had a large influence upon the results. Our quantitative estimates indicate that ragweed pollen allergy will become a common health problem across Europe, expanding into areas where it is currently uncommon. Control of ragweed spread may be an important adaptation strategy in response to climate change. Citation: Lake IR, Jones NR, Agnew M, Goodess CM, Giorgi F, Hamaoui-Laguel L, Semenov MA, Solomon F, Storkey J, Vautard R, Epstein MM. 2017. Climate change and future pollen allergy in Europe. Environ Health Perspect 125:385-391; http://dx.doi.org/10.1289/EHP173.

Impacts of the spatial extent of pollen-climate calibration-set on the absolute values, range and trends of reconstructed Holocene precipitation

NASA Astrophysics Data System (ADS)

Cao, X.; Tian, F.; Telford, R.; Ni, J.; Xu, Q.; Chen, F.; Liu, X.; Stebich, M.; Zhao, Y.; Herzschuh, U.

2017-12-01

Pollen-based quantitative reconstructions of past climate variables is a standard palaeoclimatic approach. Despite knowing that the spatial extent of the calibration-set affects the reconstruction result, guidance is lacking as to how to determine a suitable spatial extent of the pollen-climate calibration-set. In this study, past mean annual precipitation (Pann) during the Holocene (since 11.5 cal ka BP) is reconstructed repeatedly for pollen records from Qinghai Lake (36.7°N, 100.5°E; north-east Tibetan Plateau), Gonghai Lake (38.9°N, 112.2°E; north China) and Sihailongwan Lake (42.3°N, 126.6°E; north-east China) using calibration-sets of varying spatial extents extracted from the modern pollen dataset of China and Mongolia (2559 sampling sites and 168 pollen taxa in total). Results indicate that the spatial extent of the calibration-set has a strong impact on model performance, analogue quality and reconstruction diagnostics (absolute value, range, trend, optimum). Generally, these effects are stronger with the modern analogue technique (MAT) than with weighted averaging partial least squares (WA-PLS). With respect to fossil spectra from northern China, the spatial extent of calibration-sets should be restricted to ca. 1000 km in radius because small-scale calibration-sets (<800 km radius) will likely fail to include enough spatial variation in the modern pollen assemblages to reflect the temporal range shifts during the Holocene, while too broad a scale calibration-set (>1500 km radius) will include taxa with very different pollen-climate relationships. Based on our results we conclude that the optimal calibration-set should 1) cover a reasonably large spatial extent with an even distribution of modern pollen samples; 2) possess good model performance as indicated by cross-validation, high analogue quality, and excellent fit with the target fossil pollen spectra; 3) possess high taxonomic resolution, and 4) obey the modern and past distribution ranges of taxa inferred from palaeo-genetic and macrofossil studies.

Quantification of toxins in a Cry1Ac + CpTI cotton cultivar and its potential effects on the honey bee Apis mellifera L.

PubMed

Han, Peng; Niu, Chang-Ying; Lei, Chao-Liang; Cui, Jin-Jie; Desneux, Nicolas

2010-11-01

Transgenic Cry1Ac + CpTI cotton (CCRI41) is increasingly planted throughout China. However, negative effects of this cultivar on the honey bee Apis mellifera L., the most important pollinator for cultivated ecosystem, remained poorly investigated. The objective of our study was to evaluate the potential side effects of transgenic Cry1Ac + CpTI pollen from cotton on young adult honey bees A. mellifera L. Two points emphasized the significance of our study: (1) A higher expression level of insecticidal protein Cry1Ac in pollen tissues was detected (when compared with previous reports). In particular, Cry1Ac protein was detected at 300 ± 4.52 ng g(-1) [part per billion (ppb)] in pollen collected in July, (2) Effects on chronic mortality and feeding behaviour in honey bees were evaluated using a no-choice dietary feeding protocol with treated pollen, which guarantee the highest exposure level to bees potentially occurring in natural conditions (worst case scenario). Tests were also conducted using imidacloprid-treated pollen at a concentration of 48 ppb as positive control for sublethal effect on feeding behaviour. Our results suggested that Cry1Ac + CpTI pollen carried no lethal risk for honey bees. However, during a 7-day oral exposure to the various treatments (transgenic, imidacloprid-treated and control), honey bee feeding behaviour was disturbed and bees consumed significantly less CCRI41 cotton pollen than in the control group in which bees were exposed to conventional cotton pollen. It may indicate an antifeedant effect of CCRI41 pollen on honey bees and thus bees may be at risk because of large areas are planted with transgenic Bt cotton in China. This is the first report suggesting a potential sublethal effect of CCRI41 cotton pollen on honey bees. The implications of the results are discussed in terms of risk assessment for bees as well as for directions of future work involving risk assessment of CCRI41 cotton.

Reevaluation of pollen quantitation by an automatic pollen counter.

PubMed

Muradil, Mutarifu; Okamoto, Yoshitaka; Yonekura, Syuji; Chazono, Hideaki; Hisamitsu, Minako; Horiguchi, Shigetoshi; Hanazawa, Toyoyuki; Takahashi, Yukie; Yokota, Kunihiko; Okumura, Satoshi

2010-01-01

Accurate and detailed pollen monitoring is useful for selection of medication and for allergen avoidance in patients with allergic rhinitis. Burkard and Durham pollen samplers are commonly used, but are labor and time intensive. In contrast, automatic pollen counters allow simple real-time pollen counting; however, these instruments have difficulty in distinguishing pollen from small nonpollen airborne particles. Misidentification and underestimation rates for an automatic pollen counter were examined to improve the accuracy of the pollen count. The characteristics of the automatic pollen counter were determined in a chamber study with exposure to cedar pollens or soil grains. The cedar pollen counts were monitored in 2006 and 2007, and compared with those from a Durham sampler. The pollen counts from the automatic counter showed a good correlation (r > 0.7) with those from the Durham sampler when pollen dispersal was high, but a poor correlation (r < 0.5) when pollen dispersal was low. The new correction method, which took into account the misidentification and underestimation, improved this correlation to r > 0.7 during the pollen season. The accuracy of automatic pollen counting can be improved using a correction to include rates of underestimation and misidentification in a particular geographical area.

Individual pollen exposure measurements: are they feasible?

PubMed

Berger, Uwe; Kmenta, Maximilian; Bastl, Katharina

2014-06-01

The purpose of the recent review is to give insight into recent attempts to measure individual pollen exposure and to give advice for interpreting such data. It is well recognized that there are various challenges in monitoring the atmospheric content of pollen in the air. Although pollen data gathered by Hirst type spore traps and evaluated by human expertise are of inestimable value because of long-time data series and as the basic foundation for pollen information services as well as for diagnosis and therapy of pollen allergies, there is a need for more precise information for individual pollen allergy sufferers. Different types of individual pollen exposure measurement samplers are presented, and estimates are offered. Further developments, especially standardization of personal pollen samplers, are needed. Improvements should lead to more usability. Because of a variety of factors, a pollen count will always stay a pollen count, and a pollen forecast is not a symptom forecast, something pollen allergy sufferers actually desire. Thus, a different promising path to individualized pollen information was recently chosen: personal pollen information is now possible based on personal symptom data and regional pollen data. In future, personal pollen data could complete this achievement.

Post-pollination mechanisms in Nicotiana longiflora and N. plumbaginifolia: pollen tube growth rate, offspring paternity and hybridization.

PubMed

Figueroa-Castro, Dulce M; Holtsford, Timothy P

2009-09-01

In natural populations where interfertile species coexist, conspecific and heterospecific pollen can be delivered to the stigmas. Post-pollination mechanisms might determine the seed siring success of different pollen donors within species as well as the chances for hybridization between species. Nicotiana longiflora and N. plumbaginifolia occur in sympatry in Northwest Argentina, where they have overlapping flowering seasons and share floral visitors. We explored (1) pollen tube growth rates for outcross versus self pollen in single-donor pollinations; (2) siring success of self versus outcross pollen donors in competitive pollinations, and (3) possibilities for hybridization by performing two- (outcross conspecific vs. heterospecific) and three-pollen donor (self vs. outcross vs. heterospecific) crosses. In N. longiflora, both pollen tube growth rate and siring success favored outcross pollen over self pollen and strong rejection of heterospecific pollen. In N. plumbaginifolia, pollen tube growth rate was similar for self and outcross pollen, self pollen sired similar numbers of offspring than outcross pollen and heterospecific pollen sired roughly the same number of progeny than self pollen. Results suggest that in natural sympatric populations, interspecific crosses would likely lead to unidirectional hybridization with N. plumbaginifolia as the seed parent.

Static and elevated pollen traps do not provide an accurate assessment of personal pollen exposure.

PubMed

Penel, V; Calleja, M; Pichot, C; Charpin, D

2017-03-01

Background. Volumetric pollen traps are commonly used to assess pollen exposure. These traps are well suited for estimating the regional mean airborne pollen concentration but are likely not to provide an accurate index of personal exposure. In this study, we tested the hypothesis that hair sampling may provide different pollen counts from those from pollen traps, especially when the pollen exposure is diverse. Methods. We compared pollen counts in hair washes to counts provided by stationary volumetric and gravimetric pollen traps in 2 different settings: urban with volunteers living in short distance from one another and from the static trap and suburban in which volunteers live in a scattered environment, quite far from the static trap. Results. Pollen counts in hair washes are in full agreement with trap counts for uniform pollen exposure. In contrast, for diverse pollen exposure, .individual pollen counts in hair washes vary strongly in quantity and taxa composition between individuals and dates. These results demonstrate that the pollen counts method (hair washes vs. stationary pollen traps) may lead to different absolute and relative contributions of taxa to the total pollen count. Conclusions. In a geographic area with a high diversity of environmental exposure to pollen, static pollen traps, in contrast to hair washes, do not provide a reliable estimate of this higher diversity.

Impact and correlation of environmental conditions on pollen counts in Karachi, Pakistan.

PubMed

Perveen, Anjum; Khan, Muneeba; Zeb, Shaista; Imam, Asif Ali

2015-02-01

A quantitative and qualitative survey of airborne pollen was performed in the city of Karachi, and the pollen counts were correlated with different climatic conditions. The aim of the study was to determine the possible effect of meteorological factors on airborne pollen distribution in the atmosphere of Karachi city. Pollen sampling was carried out by using Burkard spore Trap for the period of August 2009 to July 2010, and a total of 2,922 pollen grains/m(3) were recorded. In this survey, 22 pollen types were recognized. The highest pollen count was contributed by Poaceae pollen type (1,242 pollen grains/m(3)) followed by Amaranthaceae/Chenopodiaceae (948 pollen grains/m(3)), Cyperus rotundus (195 pollen grains/m(3)) and Prosopis juliflora (169 pollen grains/m(3)). Peak pollen season was in August showing a total of 709 pollen grains/m(3) and lowest pollen count was observed in January-2010. Pearson's chi-square test was performed for the possible correlation of pollen counts and climatic factors. The test revealed significant positive correlation of wind speed with pollen types of Amaranthaceae/Chenopodiaceae; Brassica campestris; Asteraceae; and Thuja orientalis. While the correlation of "average temperature" showed significant positive value with Asteraceae and Tamarix indica pollen types. Negative correlation was observed between humidity/ precipitation and pollen types of Brassica campestris; Daucus carota; Ephedra sp.; and Tamarix indica. In the light of above updated data one could identify various aeroallergens present in the air of Karachi city.

The Anaphase-Promoting Complex is a dual integrator that regulates both microRNA-mediated transcriptional regulation of Cyclin B1 and degradation of Cyclin B1 during Arabidopsis male gametophyte development

USDA-ARS?s Scientific Manuscript database

The anaphase-promoting complex/cyclosome (APC/C), an essential ubiquitin protein ligase, regulates mitotic progression and exit by enhancing degradation of cell cycle regulatory proteins, such as CYCB1;1, whose transcripts are upregulated by DUO POLLEN1 (DUO1). DUO1 is required for cell division in ...

The Anaphase-Promoting Complex Is a Dual Integrator That Regulates Both MicroRNA-Mediated Transcriptional Regulation of Cyclin B1 and Degradation of Cyclin B1 during Arabidopsis Male Gametophyte Development

USDA-ARS?s Scientific Manuscript database

The anaphase-promoting complex/cyclosome (APC/C), an essential ubiquitin protein ligase, regulates mitotic progression and exit by enhancing degradation of cell cycle regulatory proteins, such as CYCB1;1, whose transcripts are upregulated by DUO POLLEN1 (DUO1). DUO1 is required for cell division in ...

True-breeding targeted gene knock-out in barley using designer TALE-nuclease in haploid cells.

PubMed

Gurushidze, Maia; Hensel, Goetz; Hiekel, Stefan; Schedel, Sindy; Valkov, Vladimir; Kumlehn, Jochen

2014-01-01

Transcription activator-like effector nucleases (TALENs) are customizable fusion proteins able to cleave virtually any genomic DNA sequence of choice, and thereby to generate site-directed genetic modifications in a wide range of cells and organisms. In the present study, we expressed TALENs in pollen-derived, regenerable cells to establish the generation of instantly true-breeding mutant plants. A gfp-specific TALEN pair was expressed via Agrobacterium-mediated transformation in embryogenic pollen of transgenic barley harboring a functional copy of gfp. Thanks to the haploid nature of the target cells, knock-out mutations were readily detected, and homozygous primary mutant plants obtained following genome duplication. In all, 22% of the TALEN transgenics proved knocked out with respect to gfp, and the loss of function could be ascribed to the deletions of between four and 36 nucleotides in length. The altered gfp alleles were transmitted normally through meiosis, and the knock-out phenotype was consistently shown by the offspring of two independent mutants. Thus, here we describe the efficient production of TALEN-mediated gene knock-outs in barley that are instantaneously homozygous and non-chimeric in regard to the site-directed mutations induced. This TALEN approach has broad applicability for both elucidating gene function and tailoring the phenotype of barley and other crop species.

Springtime carbon episodes at Gosan background site revealed by total carbon, stable carbon isotopic composition, and thermal characteristics of carbonaceous particles

NASA Astrophysics Data System (ADS)

Jung, J.; Kawamura, K.

2011-05-01

In order to investigate the carbon episodes at Gosan background super-site (33.17° N, 126.10° E) in East Asia during spring of 2007 and 2008, total suspended particles (TSP) were collected and analyzed for particulate organic carbon, elemental carbon, total carbon (TC), total nitrogen (TN), and stable carbon isotopic composition (δ13C) of TC. The carbon episodes at the Gosan site were categorized as long-range transported anthropogenic pollutant (LTP) from Asian continent, Asian dust (AD) accompanying with LTP, and local pollen episodes. The stable carbon isotopic composition of TC (δ13CTC) was found to be lowest during the pollen episodes (range: -26.2 ‰ to -23.5 ‰, avg.: -25.2 ± 0.9 ‰), followed by the LTP episodes (range: -23.5 ‰ to -23.0 ‰, avg.: -23.3 ± 0.3 ‰) and the AD episodes (range: -23.3 to -20.4 %, avg.: -21.8 ± 2.0 ‰). The δ13CTC of the airborne pollens (-28.0 ‰) collected at the Gosan site showed value similar to that of tangerine fruit (-28.1 ‰) produced from Jeju Island. Based on the carbon isotope mass balance equation and the TN and TC regression approach, we found that ∼40-45 % of TC in the TSP samples during the pollen episodes was attributed to airborne pollens from Japanese cedar trees planted around tangerine farms in Jeju Island. The δ13C of citric acid in the airborne pollens (-26.3 ‰) collected at the Gosan site was similar to that in tangerine fruit (-27.4 ‰). The negative correlation between the citric acid-carbon/TC ratios and δ13CTC were obtained during the pollen episodes. These results suggest that citric acid emitted from tangerine fruit may be adsorbed on the airborne pollens and then transported to the Gosan site. Based on the thermal evolution pattern of organic aerosols during the carbon episodes, we found that organic aerosols originated from East China are more volatile on heating and are more likely to form pyrolized organic carbon than the pollen-enriched organic aerosols and organic aerosols originated from Northeast China. Since thermal evolution patterns of organic aerosols are highly influenced by their molecular weight, they can be used as additional information on the formation of secondary organic aerosols during the long-range atmospheric transport and the source regions of organics.

The oligolectic bee Osmia brevis sonicates Penstemon flowers for pollen: A newly documented behavior for the Megachilidae

Treesearch

James H. Cane

2014-01-01

Flowers with poricidally dehiscent anthers are typically nectarless but are avidly visited and often solely pollinated by bees that sonicate the flowers to harvest pollen. Sonication results from shivering the thoracic flight muscles. Honey bees (Apis) and the 4,000+ species of Megachilidae are enigmatic in their seeming inability to sonicate flowers. The oligolectic...

Pollen-inferred quantitative reconstructions of Holocene land-cover in NW Europe for the evaluation of past climate-vegetation feedbacks - methods and first maps of the cover of plant functional types at 6000, 3000, 600, 200 and 0 BP.

NASA Astrophysics Data System (ADS)

Trondman, Anna-Kari; Gaillard, Marie-José; Sugita, Shinya; Mazier, Florence; Fyfe, Ralph; Nielsen, Anne-Birgitte; Leydet, Michelle; Members, Landclim

2010-05-01

Quantitative estimates of land-cover changes during the Holocene have become increasingly important for a better understanding of the earth surface-atmosphere feedbacks, and refining climate models. The LANDCLIM project and research network (sponsored by the Swedish [VR] and Nordic [NordForsk] Research Councils) (see Gaillard et al., CL 1.22) have the objective to quantify human-induced changes in regional land-cover in NW Europe during the Holocene, and to evaluate the effects of these changes on the regional climate through altered feedbacks. We use the REVEALS model to estimate the percentage cover of groups of taxa (plant functional types, PFTs) from fossil pollen data. The past cover of PFTs will be compared with the outputs of the LPJ-GUESS, a widely-used dynamic vegetation model, and applied as an alternative to the simulated LPG-GUESS vegetation to run the regional climate model RCA3 for the past. The REVEALS model requires raw pollen counts, site radius, pollen productivity estimates (PPEs), and fall speed of pollen (FS). PPEs and FS are available for 34 taxa in the study area. The study area is divided between four principle investigators within the LANDCLIM project. A protocol was established in order to standardize the strategy and methods applied to prepare the pollen data and run REVEALS. It includes instructions for both data contributors and users on 1) chronologies, 2) pollen taxa and harmonization with the PPEs available, and 3) number of pollen taxa and datasets of PPEs to use in alternative test runs. New age-depth models were performed for several records to ensure consistency in the chronologies. The pollen records are selected from pollen databases, i.e. the European Pollen Database (EPD), the Czech Pollen Database (PALYCZ) and the Alpine Pollen Database (ALPDABA), as well as obtained directly from the authors. Using the pollen records of the Czech Pollen Database, the effect on the REVEALS estimates of 1) basin type (lakes or bogs), 2) number of pollen taxa, 3) PPEs dataset, and 4) number of dates per record used to establish the chronology (≥3 or ≥5) was tested (see Mazier et al. CL 1.21). Following the results of these tests, the first maps are based on REVEALS runs using pollen records from both lakes and bogs with ≥3 dates, 24 taxa (entomophilous taxa excluded), and the mean of all PPEs available in the study area. The maps are produced for 10 PFTs (LPJ-GUESS) and 3 PFTs (RCA3) at a spatial resolution of 1o x 1o for five selected time windows of the Holocene with contrasting human-induced land-cover (0-100 cal BP, 100-350 cal BP, 350-700 cal BP, 2700-3200 cal BP and 5700-6200 cal BP). The maps of PFTs show significant changes in the degree of human-induced vegetation openness through the Holocene over most of the study area. There are large discrepancies between these first quantitative land-cover maps and earlier maps based on pollen data and other methods such as biomization and the modern analogue approach. * The following LANDCLIM members are acknowledged for providing pollen records and for help with pollen databases: Teija Alenius (Espoo), Heather Almquist-Jacobson (Montana, USA), Lena Barnekow and Thomas Persson (Lund), Jonas Bergman (Stockholm), Anne Bjune and John Birks (Bergen), Thomas Giesecke (Göttingen), Rixt de Jong (Bern), Mihkel Kangur and Tiiuu Koff (Tallinn), Malgorzata Latalowa (Gdansk), Ann-Marie Robertsson (Stockholm), Ulf Segerström and Henrik von Stedingk (Umeå), Heikki Seppä (Helsinki). Sugita, S. 2007. The Holocene, 17, 229-241.

Understanding the ecological background of rice agriculture on the Ningshao Plain during the Neolithic Age: pollen evidence from a buried paddy field at the Tianluoshan cultural site

NASA Astrophysics Data System (ADS)

Li, Chunhai; Zheng, Yunfei; Yu, Shiyong; Li, Yongxiang; Shen, Huadong

2012-03-01

The progressive rise of atmospheric CH4 level since 5 ka has been hypothesized to result from human agricultural activities that turned forested lands, which would otherwise be a carbon sink, into paddy fields. Increasing numbers of Neolithic cultural sites unearthed in coastal eastern China, providing unique opportunities to test this hypothesis. Here, we present detailed pollen data from a buried paddy field at Tianluoshan cultural site on the Ningshao Plain, eastern China, to reconstruct the ecological conditions associated with the establishment of paddy fields. Stratigraphic data, radiocarbon ages, and pollen analyses show that vegetation underwent six phases of evolution and paddy fields were developed from 7000 to 4200 cal. yr BP. We found no evidence of slash-and-burn agriculture at the study site. Together with no presence of the irrigation system, our pollen data suggest the paddy fields at this site originated from wetlands. Hence, our findings do not support the hypothesis that anthropogenic-induced deforestation play ed a significant role in the rise of the atmospheric CH4 rise since the middle Holocene.

RNAi-mediated male sterility of tobacco by silencing TA29.

PubMed

Nawaz-ul-Rehman, Muhammad Shah; Mansoor, Shahid; Khan, Asif Ali; Zafar, Yusuf; Briddon, Rob W

2007-06-01

The superior performance of F1 hybrids has a significant impact on agricultural productivity. For commercial application, the availability of an efficient system for obtaining male-sterile lines of crops is an essential prerequisite. Here we have investigated the use of RNA interference (RNAi) technology to silence a male-specific gene in the model host tobacco. TA29 is expressed exclusively in anthers at the time of microspore development. About 10 out of 13 tobacco lines transformed with a hairpin RNAi construct containing TA29 sequences were male sterile. Transgenic plants were phenotypically indistinguishable from non-transgenic plants. At the anthesis stage, pollen grains from transgenic, male-sterile plants were aborted and lysed in comparison to the round and fully developed pollen in non-transgenic plants. Microscopic analysis of anthers showed selective degradation of tapetum in transgenic plants with no microspore development. One week after self-pollination, the ovules of non-transgenic plants were double the size of those in transgenic plants, due to successful self-fertilization. Male sterile transgenic plants set seed normally, when cross-pollinated with pollen from non-transgenic plants, confirming no adverse effect on the female parts of the flower. These results show that silencing of male-specific genes by RNAi is potentially a useful tool for generating male-sterile lines for producing hybrid seed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Underbrink, A.G.; Sparrow, A.H.; Pond, V.

The effects of x or gamma rays and 0.43-MeV neutrons on pollen abortion, as measured by cotton blue staining, were studied in fifteen rnembers of four genera (Floscopa, Gibasis, Tradescantia, and Tripogandra) of the family Commelinaceae. The roles of interphase chromosome volume (ICV), nuclear volume (NV), and ploidy on the degree of pollen abortion induced by radiation were investigated. For each species, the maximum percentage of aborted grains was determined over a postirradiation period equivalent to an entire period of microsporogenesis. Dose-response curves were constructed for each species and these were found to vary in slope. From these curves, RBEmore » values were determined for two species of Tradescantia and for a diploid and tetraploid species of Gibasis. Within the dose range investigated, highest RBEs at 10% pollen abortion ranged from about 23 for Gibasis karwinskyana (4x) to about 9.4 for the diploid Gibasis. Ploidy was not found to influence the radiation response to an appreciable extent when ICVs were similar. High polyploids with small ICVs were found to be more radioresistant, but this response appears to be a function of ICV and not the degree of ploidy. Correlations were sought between 50% pollen abortion and ICV or NV. No correlations were found using NV. However, following low LET radiation an inverse relationship (-1 slope) was obtained between 50% pollen abortion and ICV. The same relation appears to hold for neutrons, but since only four species were available for comparison this relationship is still inconclusive. (auth)« less

Fruit Set and Single Visit Stigma Pollen Deposition by Managed Bumble Bees and Wild Bees in Citrullus lanatus (Cucurbitales: Cucurbitaceae).

PubMed

Campbell, Joshua W; Daniels, Jaret C; Ellis, James D

2018-04-02

Pollinators provide essential services for watermelon, Citrullus lanatus (Thunb.; Cucurbitales: Cucurbitaceae). Managed bumble bees, Bombus impatiens (Cresson; Hymenoptera: Apidae), have been shown to be a useful watermelon pollinator in some areas. However, the exact contribution bumble bees make to watermelon pollination and how their contribution compares to that of other bees is unclear. We used large cages (5.4 × 2.5 × 2.4 m) to confine bumble bee hives to watermelon plants and compared fruit set in those cages to cages containing watermelons but no pollinators, and to open areas of field next to cages (allows all pollinators). We also collected data on single visit pollen deposition onto watermelon stigmas by managed bumble bees, honey bees, and wild bees. Overall, more fruit formed within the open cages than in cages of the other two treatment groups. B. impatiens and Melissodes spp. deposited the most pollen onto watermelon stigmas per visit, but all bee species observed visiting watermelon flowers were capable of depositing ample pollen to watermelon stigmas. Although B. impatiens did deposit large quantities of pollen to stigmas, they were not common within the field (i.e., outside the cages) as they were readily drawn to flowering plants outside of the watermelon field. Overall, bumble bees can successfully pollinate watermelon, but may be useful in greenhouses or high tunnels where watermelon flowers have no competition from other flowering plants that could draw bumble bees away from watermelon.

Charting novel allergens from date palm pollen (Phoenix sylvestris) using homology driven proteomics.

PubMed

Saha, Bodhisattwa; Bhattacharya, Swati Gupta

2017-08-08

Pollen grains from Phoenix sylvestris (date palm), a commonly cultivated tree in India has been found to cause severe allergic diseases in an increasing percentage of hypersensitive individuals. To unearth its allergenic components, pollen protein were profiled by two-dimensional gel electrophoresis followed by immunoblotting with date palm pollen sensitive patient sera. Allergens were identified by MALDI-TOF/TOF employing a layered proteomic approach combining conventional database dependent search and manual de novo sequencing followed by homology-based search as Phoenix sylvestris is unsequenced. Derivatization of tryptic peptides by acetylation has been demonstrated to differentiate the 'b' from the 'y' ions facilitating efficient de novo sequencing. Ten allergenic proteins were identified, out of which six showed homology with known allergens while others were reported for the first time. Amongst these, isoflavone reductase, beta-conglycinin, S-adenosyl methionine synthase, 1, 4 glucan synthase and beta-galactosidase were commonly reported as allergens from coconut pollen and presumably responsible for cross-reactivity. One of the allergens had IgE binding epitope recognized by its glycan moiety. The allergenic potency of date palm pollen has been demonstrated using in vitro tests. The identified allergens can be used to develop vaccines for immunotherapy against date palm pollen allergy. Identification of allergenic proteins from sources harboring them is essential in developing therapeutic interventions. This is the first comprehensive study on the identification of allergens from Phoenix sylvestris (date palm) pollen, one of the major aeroallergens in India using a proteomic approach. Proteomic methods are being increasingly used to identify allergens. However, since many of these proteins arise from species which are un-sequenced, it becomes difficult to interpret those using conventional proteomics. Date palm being an unsequenced species, the IgE-reactive proteins have been identified using a stratified proteomic workflow incorporating manual de novo sequencing and homology-based proteomics. This study also gives an insight into the presence of glycan nature of the IgE binding epitopes. Five proteins have been found to be common with coconut pollen allergens and presumably responsible for cross-reactivity. These can be used in diagnostics to differentiate patient cohorts allergic to both coconut and date palm pollen from true date palm pollen allergic subjects. This would also determine better specific immunotherapy regimes between the two cohorts. The allergens identified herein have potential towards vaccine development in date palm pollen allergy as well as in enriching the existing catalogue of allergenic proteins. Copyright © 2017. Published by Elsevier B.V.

Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

NASA Astrophysics Data System (ADS)

Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

2018-02-01

Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300-500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in radiocarbon dating, and correlation between pollen and brGDGT temperature reconstructions rules out vegetation lags as a cause. However, the YD termination appears synchronous among the brGDGT record, regional pollen stack, and Northern Hemisphere stack. The cause of the larger and lagged temperature changes in the southern Great Lakes relative to Northern Hemisphere averages remains unclear, but may be due to the effects of continentality and ice sheet extent on regional climate evolution.

Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

USGS Publications Warehouse

Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

2018-01-01

Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300–500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in radiocarbon dating, and correlation between pollen and brGDGT temperature reconstructions rules out vegetation lags as a cause. However, the YD termination appears synchronous among the brGDGT record, regional pollen stack, and Northern Hemisphere stack. The cause of the larger and lagged temperature changes in the southern Great Lakes relative to Northern Hemisphere averages remains unclear, but may be due to the effects of continentality and ice sheet extent on regional climate evolution.

Effect of artificial feeders on pollen loads of the hummingbirds of Cerro de la Muerte, Costa Rica.

PubMed

Avalos, Gerardo; Soto, Alejandra; Alfaro, Willy

2012-03-01

Although sugar-water feeders are commonly used by enthusiasts to attract hummingbirds, little is known about how they affect hummingbird behavior and flower use. We studied the highland hummingbird assemblage of Cerro de La Muerte, Costa Rica, both at a site with permanent feeders (La Georgina Restaurant) and further from it. We examined how feeder use and monopolization affected seasonal changes in pollen loads during four sampling periods, including dry and wet seasons, from 2003-2005. We expected that species monopolizing the feeders would carry little or no pollen whatsoever, and would have pollen loads characterized by low floral diversity, in contrast with species less dependent on feeders. We obtained pollen samples from 183 individuals of four hummingbird species captured around the feeders using mist nets, which were compared with a pollen reference collection of plants with a pollination syndrome by hummingbirds. The same methods were implemented at a site 3km away from the feeders. Feeder usage was quantified by counting the number of times hummingbirds drank from the feeders in periods of 4min separated by 1min. The effects of hummingbird species and season on pollen load categories were assessed using a nominal logistic regression. The alpha species at the site, the Fiery-throated Hummingbird (Panterpe insignis), dominated the feeders during the dry season. Meanwhile, in the wet season, feeder usage was more evenly distributed across species, with the exception of the Volcano Hummingbird, Selasphorus flammula, which occupies the last place in the dominance hierarchy. Pollen loads of hummingbirds captured near feeders were low in abundance (more than 50% of captured individuals had zero or low pollen loads), and low in species richness (96% of the hummingbirds with pollen from only one plant genus, Centropogon). Overall pollen loads increased during the dry season coinciding with peaks in flower availability, although the majority of captured hummingbirds carried no pollen. Mist nets located 3km from La Georgina returned few captures (one-to-three specimens) per sampling date, contrasting with observations made before feeders were present. These results suggest that sugar-water feeders gather hummingbirds in over considerable distances drawing them away from flowers. The competitive and antagonistic pattern shown between feeders and flowers indicate that natural pollination system could be significantly altered. Supplementing hummingbirds with food seems likely to interfere with pollination networks already stressed by many anthropogenic effects.

Knockin' on pollen's door: live cell imaging of early polarization events in germinating Arabidopsis pollen

PubMed Central

Vogler, Frank; Konrad, Sebastian S. A.; Sprunck, Stefanie

2015-01-01

Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To simultaneously track germinating pollen from up to 12 genetically different plants we developed an inexpensive and easy mounting technique, suitable for every standard microscope setup. We performed high magnification live-cell imaging during Arabidopsis pollen activation, germination, and the establishment of pollen tube tip growth by using fluorescent marker lines labeling either the pollen cytoplasm, vesicles, the actin cytoskeleton or the sperm cell nuclei and membranes. Our studies revealed distinctive vesicle and F-actin polarization during pollen activation and characteristic growth kinetics during pollen germination and pollen tube formation. Initially, the germinating Arabidopsis pollen tube grows slowly and forms a uniform roundish bulge, followed by a transition phase with vesicles heavily accumulating at the growth site before switching to rapid tip growth. Furthermore, we found the two sperm cells to be transported into the pollen tube after the phase of rapid tip growth has been initiated. The method presented here is suitable to quantitatively study subcellular events during Arabidopsis pollen germination and growth, and for the detailed analysis of pollen mutants with respect to pollen polarization, bulging, or growth site selection at the pollen plasma membrane. PMID:25954283

Does stronger pollen competition improve offspring fitness when pollen load does not vary?

PubMed

Pélabon, Christophe; Hennet, Lauriane; Bolstad, Geir H; Albertsen, Elena; Opedal, Øystein H; Ekrem, Runa K; Armbruster, W Scott

2016-03-01

Competition among pollen grains from a single donor is expected to increase the quality of the offspring produced because of the recessive deleterious alleles expressed during pollen-tube growth. However, evidence for such an effect is inconclusive; a large number of studies suffer from confounding variation in pollen competition with variation in pollen load. In this study, we tested the effect of pollen competition on offspring performance independently of pollen-load variation. We compared seed mass and early seedling performance in Dalechampia scandens (Euphorbiaceae) between crosses in which variation in pollen competition was achieved, without variation in pollen load, by manipulating the dispersion of pollen grains on the stigmas. Despite a large sample size (211 crosses on 20 maternal plants), we failed to find an effect of pollen competition on seed characteristics or early seedling performance. Paternal effects were always limited, and pollen competition never reduced the within-father (residual) variance. These results suggest that limited within-donor variation in genetic quality of pollen grains reduces the potential benefits of pollen competition in the study population. The lack of paternal effects on early sporophyte performance further suggests that benefits of pollen competition among pollen from multiple donors should be limited as well, and it raises questions about the significance of pollen competition as a mechanism of sexual selection. © 2016 Botanical Society of America.

Perinatal risk factors for asthma in children with allergic rhinitis and grass pollen sensitization.

PubMed

Yavuz, S Tolga; Siebert, Stephanie; Akin, Onur; Arslan, Mutluay; Civelek, Ersoy; Bagci, Soyhan

2018-05-01

Results of epidemiologic studies have determined several risk factors for asthma in school-age children. To examine whether parental and perinatal risk factors, along with infantile feeding patterns, were associated with asthma in children with grass pollen allergy and allergic rhinitis. We retrospectively analyzed the data of our cohort, which consisted of children with allergic rhinitis. Only children with grass pollen sensitization were enrolled. A detailed questionnaire regarding demographic features and perinatal events was given to the parents. A total of 293 children (200 boys [68.3%]; with median age, 10.2 years [interquartile range {IQR}, 7.4-13.0 years]) were included. A total of 109 children (37.2%) had accompanying asthma. The median age of onset of rhinitis symptoms was earlier (5.3 years [IQR, 4.0-8.0 years] versus 7.0 years [IQR, 5.0-10.0 years]; p = 0.001), histories of prematurity (16.7 versus 6.5%; p = 0.006), preeclampsia (5.5 versus 0%; p = 0.001), neonatal intensive care unit admission (15.1 versus 6.0%; p = 0.01), phototherapy (17.9 versus 7.1%; p = 0.004), early formula feeding (58.7 versus 41.2%; p = 0.006), and parental asthma (25.0 versus 11.4%; p = 0.002) were more frequent in children with asthma. Multivariate logistic regression analysis revealed prematurity (odds ratio [OR] 2.78 [95% confidence interval [CI],1.24-6.24]; p = 0.013), history of formula feeding (OR 1.81 [95% CI, 1.09-3.01]; p = 0.022), and parental asthma (OR 2.37 [95% CI, 1.22-4.63]; p = 0.011) were associated with asthma in school-age children with grass pollen-induced allergic rhinitis. Close monitoring of patients with these risk factors may help with an earlier diagnosis of asthma and prompt initiation of therapeutic interventions in children with allergic rhinitis and who were sensitized to grass pollen.

Selfing, Local Mate Competition, and Reinforcement.

PubMed

Rausher, Mark D

2017-02-01

Reinforcement can contribute to speciation by increasing the strength of prezygotic isolating mechanisms. Theoretical analyses over the past two decades have demonstrated that conditions for reinforcement are not unduly restrictive, and empirical investigations have documented over a dozen likely cases, indicating that it may be a reasonably common phenomenon in nature. Largely uncharacterized, however, is the diversity of biological scenarios that can create the reduced hybrid fitness that drives reinforcement. Here I examine one such scenario-the evolution of the "selfing syndrome" (a suite of characters including reductions in flower size and in nectar, pollen, and scent production) in highly selfing plant species. Using a four-locus model, where the loci are (1) a discrimination locus, (2) a target-of-discimination locus, (3) a pollen-production locus, and (4) a selfing-rate locus, I determine the conditions under which this syndrome can favor reinforcement, an increase in discrimination through change at locus 1, in an outcrossing species that experiences gene flow from a highly selfing species. In the absence of both linkage disequilibrium between loci and pollen discounting, reinforcement can occur, but only in a very small fraction of the parameter combinations examined. Moderate linkage ([Formula: see text]) between one pair of loci increases this fraction moderately, depending on which two loci are linked. Pollen discounting (a reduction in pollen exported to other plants due to increased selfing), by contrast, can increase the fraction of parameter combinations that result in reinforcement substantially. The evolution of reduced pollen production in highly selfing species thus facilitates reinforcement, especially if substantial pollen discounting is associated with selfing.

Aeropalynology

ERIC Educational Resources Information Center

Biesboer, David

1977-01-01

Contains information regarding pollen and human allergies. Lists most common types of pollen, describes pollen morphology, diagrams and apparatus for collecting pollen, and suggests laboratory activities such as pollen counts, pollen concentration, dispersal, and meteorological effects. (CS)

Pollen from the Deep-Sea: A Breakthrough in the Mystery of the Ice Ages

PubMed Central

Sánchez Goñi, María F.; Desprat, Stéphanie; Fletcher, William J.; Morales-Molino, César; Naughton, Filipa; Oliveira, Dulce; Urrego, Dunia H.; Zorzi, Coralie

2018-01-01

Pollen from deep-sea sedimentary sequences provides an integrated regional reconstruction of vegetation and climate (temperature, precipitation, and seasonality) on the adjacent continent. More importantly, the direct correlation of pollen, marine and ice indicators allows comparison of the atmospheric climatic changes that have affected the continent with the response of the Earth’s other reservoirs, i.e., the oceans and cryosphere, without any chronological uncertainty. The study of long continuous pollen records from the European margin has revealed a changing and complex interplay between European climate, North Atlantic sea surface temperatures (SSTs), ice growth and decay, and high- and low-latitude forcing at orbital and millennial timescales. These records have shown that the amplitude of the last five terrestrial interglacials was similar above 40°N, while below 40°N their magnitude differed due to precession-modulated changes in seasonality and, particularly, winter precipitation. These records also showed that vegetation response was in dynamic equilibrium with rapid climate changes such as the Dangaard-Oeschger (D-O) cycles and Heinrich events, similar in magnitude and velocity to the ongoing global warming. However, the magnitude of the millennial-scale warming events of the last glacial period was regionally-specific. Precession seems to have imprinted regions below 40°N while obliquity, which controls average annual temperature, probably mediated the impact of D-O warming events above 40°N. A decoupling between high- and low-latitude climate was also observed within last glacial warm (Greenland interstadials) and cold phases (Greenland stadials). The synchronous response of western European vegetation/climate and eastern North Atlantic SSTs to D-O cycles was not a pervasive feature throughout the Quaternary. During periods of ice growth such as MIS 5a/4, MIS 11c/b and MIS 19c/b, repeated millennial-scale cold-air/warm-sea decoupling events occurred on the European margin superimposed to a long-term air-sea decoupling trend. Strong air-sea thermal contrasts promoted the production of water vapor that was then transported northward by the westerlies and fed ice sheets. This interaction between long-term and shorter time-scale climatic variability may have amplified insolation decreases and thus explain the Ice Ages. This hypothesis should be tested by the integration of stochastic processes in Earth models of intermediate complexity. PMID:29434616

Pollen from the Deep-Sea: A Breakthrough in the Mystery of the Ice Ages.

PubMed

Sánchez Goñi, María F; Desprat, Stéphanie; Fletcher, William J; Morales-Molino, César; Naughton, Filipa; Oliveira, Dulce; Urrego, Dunia H; Zorzi, Coralie

2018-01-01

Pollen from deep-sea sedimentary sequences provides an integrated regional reconstruction of vegetation and climate (temperature, precipitation, and seasonality) on the adjacent continent. More importantly, the direct correlation of pollen, marine and ice indicators allows comparison of the atmospheric climatic changes that have affected the continent with the response of the Earth's other reservoirs, i.e., the oceans and cryosphere, without any chronological uncertainty. The study of long continuous pollen records from the European margin has revealed a changing and complex interplay between European climate, North Atlantic sea surface temperatures (SSTs), ice growth and decay, and high- and low-latitude forcing at orbital and millennial timescales. These records have shown that the amplitude of the last five terrestrial interglacials was similar above 40°N, while below 40°N their magnitude differed due to precession-modulated changes in seasonality and, particularly, winter precipitation. These records also showed that vegetation response was in dynamic equilibrium with rapid climate changes such as the Dangaard-Oeschger (D-O) cycles and Heinrich events, similar in magnitude and velocity to the ongoing global warming. However, the magnitude of the millennial-scale warming events of the last glacial period was regionally-specific. Precession seems to have imprinted regions below 40°N while obliquity, which controls average annual temperature, probably mediated the impact of D-O warming events above 40°N. A decoupling between high- and low-latitude climate was also observed within last glacial warm (Greenland interstadials) and cold phases (Greenland stadials). The synchronous response of western European vegetation/climate and eastern North Atlantic SSTs to D-O cycles was not a pervasive feature throughout the Quaternary. During periods of ice growth such as MIS 5a/4, MIS 11c/b and MIS 19c/b, repeated millennial-scale cold-air/warm-sea decoupling events occurred on the European margin superimposed to a long-term air-sea decoupling trend. Strong air-sea thermal contrasts promoted the production of water vapor that was then transported northward by the westerlies and fed ice sheets. This interaction between long-term and shorter time-scale climatic variability may have amplified insolation decreases and thus explain the Ice Ages. This hypothesis should be tested by the integration of stochastic processes in Earth models of intermediate complexity.

Subtropical grass pollen allergens are important for allergic respiratory diseases in subtropical regions

PubMed Central

2012-01-01

Background Grass pollen allergens are a major cause of allergic respiratory disease but traditionally prescribing practice for grass pollen allergen-specific immunotherapy has favoured pollen extracts of temperate grasses. Here we aim to compare allergy to subtropical and temperate grass pollens in patients with allergic rhinitis from a subtropical region of Australia. Methods Sensitization to pollen extracts of the subtropical Bahia grass (Paspalum notatum), Johnson grass (Sorghum halepense) and Bermuda grass (Cynodon dactylon) as well as the temperate Ryegrass (Lolium perenne) were measured by skin prick in 233 subjects from Brisbane. Grass pollen-specific IgE reactivity was tested by ELISA and cross-inhibition ELISA. Results Patients with grass pollen allergy from a subtropical region showed higher skin prick diameters with subtropical Bahia grass and Bermuda grass pollens than with Johnson grass and Ryegrass pollens. IgE reactivity was higher with pollen of Bahia grass than Bermuda grass, Johnson grass and Ryegrass. Patients showed asymmetric cross-inhibition of IgE reactivity with subtropical grass pollens that was not blocked by temperate grass pollen allergens indicating the presence of species-specific IgE binding sites of subtropical grass pollen allergens that are not represented in temperate grass pollens. Conclusions Subtropical grass pollens are more important allergen sources than temperate grass pollens for patients from a subtropical region. Targeting allergen-specific immunotherapy to subtropical grass pollen allergens in patients with allergic rhinitis in subtropical regions could improve treatment efficacy thereby reducing the burden of allergic rhinitis and asthma. PMID:22409901

Pollen resistance to water in 80 angiosperm species: flower structures protect rain-susceptible pollen.

PubMed

Mao, Yun-Yun; Huang, Shuang-Quan

2009-08-01

Flowers exhibit adaptive responses to biotic and abiotic factors. It remains unclear whether pollen susceptibility to rain damage plays a role in the evolution of floral form. We investigated flower performance in rain and compared pollen longevity in dry conditions, pure water and solutions with different sucrose concentrations in 80 flowering species from 46 families with diverse floral shapes and pollination modes. A pollen viability test showed that pollen longevity in all studied species was greatly reduced by wetting. We found that pollen of species with complete protection by flower structures was susceptible to water damage and a high proportion of resistant pollen occurred in unprotected species. Flowers whose structures expose pollen to rain may also reduce rain damage through temporal patterns of pollen presentation. This prediction was supported by our direct measurement of pollen presentation duration on rainy days. Our observations showed that variation in pollen performance in water was associated with differences in floral forms. Water-resistant pollen and extended pollen presentation duration were favored by selection via rain contact in species in which pollen was not protected from rain. These findings support the functional hypothesis that flower structures protect susceptible pollen from rain, demonstrating that rain acts as a force shaping floral form.

The long pollen tube journey and in vitro pollen germination of Phalaenopsis orchids.

PubMed

Chen, Jhun-Chen; Fang, Su-Chiung

2016-06-01

Pollen biology in P. aphrodite. Orchids have a distinct reproductive program. Pollination triggers ovule development and differentiation within flowers, and fertilization occurs days to months after pollination. It is unclear how pollen tubes travel through the developing ovaries during ovule development and when pollen tubes arrive at the mature embryo sac to achieve fertilization. Here, we report a robust staining protocol to image and record the timing of pollen germination, progressive growth of pollen tubes in ovaries, and arrival of pollen tubes at embryo sacs in Phalaenopsis aphrodite. The pollen germinated and pollen tubes entered the ovary 3 days after pollination. Pollen tubes continued to grow and filled the entire cavity of the ovary as the ovary elongated and ovules developed. Pollen tubes were found to enter the matured embryo sacs at approximately 60-65 days after pollination in an acropetal manner. Moreover, these temporal changes in developmental events such as growth of pollen tubes and fertilization were associated with expression of molecular markers. In addition, we developed an in vitro pollen germination protocol, which is valuable to enable studies on pollen tube guidance and tip growth regulation in Phalaenopsis orchids and possibly in other orchid species.

A metabolomic, geographic, and seasonal analysis of the contribution of pollen-derived adenosine to allergic sensitization.

PubMed

Mueller, Geoffrey A; Thompson, Peter M; DeRose, Eugene F; O'Connell, Thomas M; London, Robert E

2016-12-01

Studies on ragweed and birch pollen extracts suggested that the adenosine content is an important factor in allergic sensitization. However, exposure levels from other pollens and considerations of geographic and seasonal factors have not been evaluated. This study compared the metabolite profile of pollen species important for allergic disease, specifically measured the adenosine content, and evaluated exposure to pollen-derived adenosine. An NMR metabolomics approach was used to measure metabolite concentrations in twenty-six pollen extracts. Pollen count data was analyzed from five cities to model exposure. A principal component analysis of the various metabolites identified by NMR showed that pollen extracts could be differentiated primarily by sugar content: glucose, fructose, sucrose, and myo-inositol. In extracts of 10 mg of pollen/ml, the adenosine was highest for grasses (45 μM) followed by trees (23 μM) and weeds (19 μM). Pollen count data showed that tree pollen was typically 5-10 times the amount of other pollens. At the daily peaks of tree, grass, and weed season the pollen-derived adenosine exposure per day is likely to only be 1.1, 0.11, and 0.12 μg, respectively. Seasonal models of pollen exposure and respiration suggest that it would be a rare event limited to tree pollen season for concentrations of pollen-derived adenosine to approach physiological levels. Sugar content and other metabolites may be useful in classifying pollens. Unless other factors create localized exposures that are very different from these models, pollen-derived adenosine is unlikely to be a major factor in allergic sensitization.

Pollen structure and development in Nymphaeales: insights into character evolution in an ancient angiosperm lineage.

PubMed

Taylor, Mackenzie L; Cooper, Ranessa L; Schneider, Edward L; Osborn, Jeffrey M

2015-10-01

A knowledge of pollen characters in early-diverging angiosperm lineages is essential for understanding pollen evolution and the role of pollen in angiosperm diversification. In this paper, we report and synthesize data on mature pollen and pollen ontogeny from all genera of Nymphaeales within a comparative, phylogenetic context and consider pollen evolution in this early-diverging angiosperm lineage. We describe mature pollen characters for Euryale, Barclaya, and Nymphaea ondinea, taxa for which little to no structural data exist. We studied mature pollen for all nymphaealean genera using light, scanning electron, and transmission electron microscopy. We reviewed published reports of nymphaealean pollen to provide a comprehensive discussion of pollen characters in water lilies. Nymphaeales exhibit diversity in key pollen characters, including dispersal unit size, ornamentation, aperture morphology, and tapetum type. All Nymphaeales pollen are tectate-columellate, exhibiting one of two distinct patterns of infratectal ultrastructure-a thick infratectal space with robust columellae or a thin infratectal space with thin columellae. All genera have pollen with a lamellate endexine that becomes compressed in the proximal, but not distal wall. This endexine ultrastructure supports the operculate hypothesis for aperture origin. Nymphaeaceae pollen exhibit a membranous granular layer, which is a synapomorphy of the family. Variation in pollen characters indicates that significant potential for lability in pollen development was present in Nymphaeales at the time of its divergence from the rest of angiosperms. Structural and ontogenetic data are essential for interpreting pollen characters, such as infratectum and endexine ultrastructure in Nymphaeales. © 2015 Botanical Society of America.

Late quaternary changes in lakes, vegetation, and climate in the Bonneville Basin reconstructed from sediment cores from Great Salt Lake: Chapter 11

USGS Publications Warehouse

Thompson, Robert S.; Oviatt, Charles G.; Honke, Jeffrey S.; McGeehin, John

2016-01-01

Sediment cores from Great Salt Lake (GSL) provide the basis for reconstructing changes in lakes, vegetation, and climate for the last ~ 40 cal ka. Initially, the coring site was covered by a shallow saline lake and surrounded by Artemisia steppe or steppe-tundra under a cold and dry climate. As Lake Bonneville began to rise (from ~ 30 to 28 cal ka), Pinus and subalpine conifer pollen percentages increased and Artemisia declined, suggesting the onset of wetter conditions. Lake Bonneville oscillated near the Stansbury shoreline between ~ 26 and ~ 24 cal ka, rose to the Bonneville shoreline by ~ 18 cal ka, and then fell to the Provo shoreline, which it occupied until ~ 15 cal ka. Vegetation changed during this time span, albeit not always with the same direction or amplitude as the lake. The pollen percentages of Pinus and subalpine conifers were high from ~ 25 to 21.5 cal ka, indicating cool and moist conditions during the Stansbury oscillation and for much of the rise toward the Bonneville shoreline. Pinus percentages then decreased and Artemisia became codominant, suggesting drier and perhaps colder conditions from ~ 21 to ~ 15 cal ka, when Lake Bonneville was at or near its highest levels.Lake Bonneville declined to a low level by ~ 13 cal ka, while Pinus pollen percentages increased, indicating that conditions remained cooler and moister than today. During the Younger Dryas interval, the brief Gilbert episode rise in lake level was followed by a shallow lake with a stratified water column. This lake rise occurred as Pinus pollen percentages were declining and those of Artemisia were rising (reflecting increasingly dry conditions), after which Artemisia pollen was at very high levels (suggesting cold and dry conditions) for a brief period.Since ~ 10.6 cal ka lacustrine conditions have resembled those of present-day GSL. Pollen spectra for the period from ~ 10.6 to 7.2 cal ka have low levels of conifer pollen and high (for the Holocene) levels of desert and steppe taxa, suggesting generally dry conditions with maximum aridity occurring prior to the deposition of the Mazama tephra (~ 7.6 cal ka). After ~ 10.6 cal ka, Juniperus pollen percentages began to increase and by ~ 7.2 cal ka juniper woodlands were well established on lower mountain slopes. From ~ 7 to 4 cal ka, pollen percentages fluctuated near their mean values for the entire Holocene. The neopluvial (~ 4 to 2 cal ka) was the wettest part of the Holocene, with higher levels of Juniperus pollen and lower levels for steppe and desert taxa than in older Holocene sediments. Pollen percentages for the last ~ 2 cal ka are variable, but generally indicate a return to drier conditions.

Behavior of profilins in the atmosphere and in vitro, and their relationship with the performance of airborne pollen

NASA Astrophysics Data System (ADS)

Aloisi, Iris; Del Duca, Stefano; De Nuntiis, Paola; Vega Maray, Ana M.; Mandrioli, Paolo; Gutiérrez, Pablo; Fernández-González, Delia

2018-04-01

Most pollen allergens in the air are carried by pollen grains, but the presence of airborne smaller respirable particles containing pollen allergens has also been demonstrated. Meteorological factors drastically affect the occurrence of pollen, allergen release in the air and diffusion of the latest. In order to shed light on this phenomenon, the dynamics of pollen and the pollen panallergen profilin in the air of two European cities (León, Spain and Bologna, Italy) having different weather conditions, were analyzed. Pollen sampling was performed continuously from March to June 2015 using two seven-day recording volumetric trap of Hirst-type, while the particles for aeroallergen quantification were sampled with a Burkard Cyclone sampler and the profilin content in aerosol samples was quantified using an indirect double-antibody sandwich ELISA. In both cities, pollen and profilin concentrations followed a similar trend and showed a significant correlation; however, peaks were often misaligned, with the profilin peaks following those of pollen. Several meteorological parameters, such as relative humidity, significantly influenced pollen and allergen dispersion. In vitro pollen tests were thus performed in order to mimic pollen rehydration, occurring in natural conditions and a massive protein release from allergenic pollen was detected during the early stages of pollen rehydration when profilin was also extruded from the grains. The different timing and protein amounts released from different pollen during hydration might explain, at least in part, the non-synchronous pollen and profilin peaks detected in the atmosphere.

Digestibility and nutritional value of fresh and stored pollen for honey bees (Apis mellifera scutellata).

PubMed

Nicolson, Susan W; Da Silva Das Neves, Susana; Human, Hannelie; Pirk, Christian W W

Pollen, the main protein source for honey bees, is mixed with regurgitated nectar or honey during collection and then stored as 'bee bread' before its consumption, mainly by young nurse workers. It has been suggested that storage of pollen improves its nutritional value and digestibility, but there is little evidence for such changes. We fed two fresh pollen types of different protein content (aloe and sunflower), and two stored pollen types (sunflower and a mixed pollen), to young caged worker bees. We measured daily consumption of pollen and sucrose solution, and survival after 14 days. At day 14 we recorded ovarian activation and extraction efficiency, by counting empty pollen grains in the rectal contents. Extraction efficiency is a measure of pollen digestibility. Contrary to our predictions, bees did not consume more fresh sunflower pollen than fresh aloe pollen to compensate for the lower protein content of sunflower pollen. In addition, they did not consume less sucrose solution when fed stored pollen diets that are already enriched in sugar. Consumption of stored sunflower pollen resulted in a low protein to carbohydrate (P:C) intake. Survival and ovarian activation were higher on diets giving higher P:C intakes. Extraction efficiency was high (up to 99%) for all pollen diets, and comparison of fresh and stored sunflower pollen showed that storage did not make it easier to digest. Changes to pollen during storage do not confer obvious benefits to honey bees. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-Incompatibility in Petunia inflata: The Relationship between a Self-Incompatibility Locus F-Box Protein and Its Non-Self S-RNases[W

PubMed Central

Sun, Penglin; Kao, Teh-hui

2013-01-01

The highly polymorphic S (for self-incompatibility) locus regulates self-incompatibility in Petunia inflata; the S-RNase regulates pistil specificity, and multiple S-locus F-box (SLF) genes regulate pollen specificity. The collaborative non-self recognition model predicts that, for any S-haplotype, an unknown number of SLFs collectively recognize all non-self S-RNases to mediate their ubiquitination and degradation. Using a gain-of-function assay, we examined the relationships between S2-SLF1 (for S2-allelic product of Type-1 SLF) and four S-RNases. The results suggest that S2-SLF1 interacts with S7- and S13-RNases, and the previously identified S1- and S3-RNases, but not with S5- or S11-RNase. An artificial microRNA expressed by the S2-SLF1 promoter, but not by the vegetative cell-specific promoter, Late Anther Tomato 52, suppressed expression of S2-SLF1 in S2 pollen, suggesting that SLF1 is specific to the generative cell. The S2 pollen with S2-SLF1 suppressed was compatible with S3-, S5-, S7-, S11-, and S13-carrying pistils, confirming that other SLF proteins are responsible for detoxifying S5- and S11-RNases and suggesting that S2-SLF1 is not the only SLF in S2 pollen that interacts with S3-, S7-, and S13-RNases. Petunia may have evolved at least two types of SLF proteins to detoxify any non-self S-RNase to minimize the deleterious effects of mutation in any SLF. PMID:23444333

HsfA2 Controls the Activity of Developmentally and Stress-Regulated Heat Stress Protection Mechanisms in Tomato Male Reproductive Tissues1[OPEN

PubMed Central

Simm, Stefan; Paupière, Marine Josephine; Theres, Klaus; Bovy, Arnaud; Schleiff, Enrico; Scharf, Klaus-Dieter

2016-01-01

Male reproductive tissues are more sensitive to heat stress (HS) compared to vegetative tissues, but the basis of this phenomenon is poorly understood. Heat stress transcription factors (Hsfs) regulate the transcriptional changes required for protection from HS. In tomato (Solanum lycopersicum), HsfA2 acts as coactivator of HsfA1a and is one of the major Hsfs accumulating in response to elevated temperatures. The contribution of HsfA2 in heat stress response (HSR) and thermotolerance was investigated in different tissues of transgenic tomato plants with suppressed HsfA2 levels (A2AS). Global transcriptome analysis and immunodetection of two major Hsps in vegetative and reproductive tissues showed that HsfA2 regulates subsets of HS-induced genes in a tissue-specific manner. Accumulation of HsfA2 by a moderate HS treatment enhances the capacity of seedlings to cope with a subsequent severe HS, suggesting an important role for HsfA2 in regulating acquired thermotolerance. In pollen, HsfA2 is an important coactivator of HsfA1a during HSR. HsfA2 suppression reduces the viability and germination rate of pollen that received the stress during the stages of meiosis and microspore formation but had no effect on more advanced stages. In general, pollen meiocytes and microspores are characterized by increased susceptibility to HS due to their lower capacity to induce a strong HSR. This sensitivity is partially mitigated by the developmentally regulated expression of HsfA2 and several HS-responsive genes mediated by HsfA1a under nonstress conditions. Thereby, HsfA2 is an important factor for the priming process that sustains pollen thermotolerance during microsporogenesis. PMID:26917685

Self-incompatibility in Petunia inflata: the relationship between a self-incompatibility locus F-box protein and its non-self S-RNases.

PubMed

Sun, Penglin; Kao, Teh-hui

2013-02-01

The highly polymorphic S (for self-incompatibility) locus regulates self-incompatibility in Petunia inflata; the S-RNase regulates pistil specificity, and multiple S-locus F-box (SLF) genes regulate pollen specificity. The collaborative non-self recognition model predicts that, for any S-haplotype, an unknown number of SLFs collectively recognize all non-self S-RNases to mediate their ubiquitination and degradation. Using a gain-of-function assay, we examined the relationships between S2-SLF1 (for S2-allelic product of Type-1 SLF) and four S-RNases. The results suggest that S2-SLF1 interacts with S7- and S13-RNases, and the previously identified S1- and S3-RNases, but not with S5- or S11-RNase. An artificial microRNA expressed by the S2-SLF1 promoter, but not by the vegetative cell-specific promoter, Late Anther Tomato 52, suppressed expression of S2-SLF1 in S2 pollen, suggesting that SLF1 is specific to the generative cell. The S2 pollen with S2-SLF1 suppressed was compatible with S3-, S5-, S7-, S11-, and S13-carrying pistils, confirming that other SLF proteins are responsible for detoxifying S5- and S11-RNases and suggesting that S2-SLF1 is not the only SLF in S2 pollen that interacts with S3-, S7-, and S13-RNases. Petunia may have evolved at least two types of SLF proteins to detoxify any non-self S-RNase to minimize the deleterious effects of mutation in any SLF.

Relative importance of pollen and seed dispersal across a Neotropical mountain landscape for an epiphytic orchid.

PubMed

Kartzinel, Tyler R; Shefferson, Richard P; Trapnell, Dorset W

2013-12-01

Populations of many species are isolated within narrow elevation bands of Neotropical mountain habitat, and how well dispersal maintains genetic connectivity is unknown. We asked whether genetic structure of an epiphytic orchid, Epidendrum firmum, corresponds to gaps between Costa Rican mountain ranges, and how these gaps influence pollen and seed flow. We predicted that significant genetic structure exists among mountain ranges due to different colonization histories and limited gene flow. Furthermore, we predicted that pollen movement contributes more to gene flow than seeds because seeds are released into strong winds perpendicular to the narrow northwest-southeast species distribution, while the likely pollinators are strong fliers. Individuals from 12 populations and three mountain ranges were genotyped with nuclear microsatellites (nDNA) and chloroplast sequences (cpDNA). Genetic diversity was high for both markers, while nDNA genetic structure was low (FSTn  = 0.020) and cpDNA structure was moderate (FSTc  = 0.443). Significant cpDNA barriers occurred within and among mountain ranges, but nDNA barriers were not significant after accounting for geographic distance. Consistent with these contrasting patterns of genetic structure, pollen contributes substantially more to gene flow among populations than seed (mp /ms  = 46). Pollinators mediated extensive gene flow, eroding nDNA colonization footprints, while seed flow was comparatively limited, possibly due to directional prevailing winds across linearly distributed populations. Dispersal traits alone may not accurately inform predictions about gene flow or genetic structure, supporting the need for research into the potentially crucial role of pollinators and landscape context in gene flow among isolated populations. © 2013 John Wiley & Sons Ltd.

Isolated populations of a rare alpine plant show high genetic diversity and considerable population differentiation.

PubMed

Aegisdóttir, Hafdís Hanna; Kuss, Patrick; Stöcklin, Jürg

2009-12-01

Gene flow and genetic variability within and among alpine plant populations can be greatly influenced by the steep environmental gradients and heterogeneous topography of alpine landscapes. In this study, the effects are examined of natural isolation of alpine habitats on genetic diversity and geographic structure in populations of C. thyrsoides, a rare and isolated European Alpine monocarpic perennial with limited seed dispersal capacity. Molecular diversity was analysed for 736 individuals from 32 populations in the Swiss Alps and adjacent Jura mountains using five polymorphic microsatellite loci. Pollen flow was estimated using pollen grain-sized fluorescent powder. In addition, individual-based Bayesian approaches were applied to examine population structure. High within-population genetic diversity (H(E) = 0.76) and a relatively low inbreeding coefficient (F(IS) = 0.022) were found. Genetic differentiation among populations measured with a standardized measure was considerable (G'(ST) = 0.53). A significant isolation-by-distance relationship was found (r = 0.62, P < 0.001) and a significant geographic sub-structure, coinciding with proposed postglacial migration patterns. Altitudinal location and size of populations did not influence molecular variation. Direct measures of pollen flow revealed that insect-mediated pollen dispersal was restricted to short distances within a population. The natural isolation of suitable habitats for C. thyrsoides restricts gene flow among the populations as expected for a monocarpic species with very limited seed dispersal capacities. The observed high within-population genetic diversity in this rare monocarpic perennial is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. Despite the high within-population genetic diversity, the considerable genetic differentiation and the clear western-eastern differentiation in this species merits consideration in future conservation efforts.

PCP-B class pollen coat proteins are key regulators of the hydration checkpoint in Arabidopsis thaliana pollen-stigma interactions.

PubMed

Wang, Ludi; Clarke, Lisa A; Eason, Russell J; Parker, Christopher C; Qi, Baoxiu; Scott, Rod J; Doughty, James

2017-01-01

The establishment of pollen-pistil compatibility is strictly regulated by factors derived from both male and female reproductive structures. Highly diverse small cysteine-rich proteins (CRPs) have been found to play multiple roles in plant reproduction, including the earliest stages of the pollen-stigma interaction. Secreted CRPs found in the pollen coat of members of the Brassicaceae, the pollen coat proteins (PCPs), are emerging as important signalling molecules that regulate the pollen-stigma interaction. Using a combination of protein characterization, expression and phylogenetic analyses we identified a novel class of Arabidopsis thaliana pollen-borne CRPs, the PCP-Bs (for pollen coat protein B-class) that are related to embryo surrounding factor (ESF1) developmental regulators. Single and multiple PCP-B mutant lines were utilized in bioassays to assess effects on pollen hydration, adhesion and pollen tube growth. Our results revealed that pollen hydration is severely impaired when multiple PCP-Bs are lost from the pollen coat. The hydration defect also resulted in reduced pollen adhesion and delayed pollen tube growth in all mutants studied. These results demonstrate that AtPCP-Bs are key regulators of the hydration 'checkpoint' in establishment of pollen-stigma compatibility. In addition, we propose that interspecies diversity of PCP-Bs may contribute to reproductive barriers in the Brassicaceae. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Pollen development in Annona cherimola Mill. (Annonaceae). Implications for the evolution of aggregated pollen

PubMed Central

Lora, Jorge; Testillano, Pilar S; Risueño, Maria C; Hormaza, Jose I; Herrero, Maria

2009-01-01

Background In most flowering plants, pollen is dispersed as monads. However, aggregated pollen shedding in groups of four or more pollen grains has arisen independently several times during angiosperm evolution. The reasons behind this phenomenon are largely unknown. In this study, we followed pollen development in Annona cherimola, a basal angiosperm species that releases pollen in groups of four, to investigate how pollen ontogeny may explain the rise and establishment of this character. We followed pollen development using immunolocalization and cytochemical characterization of changes occurring from anther differentiation to pollen dehiscence. Results Our results show that, following tetrad formation, a delay in the dissolution of the pollen mother cell wall and tapetal chamber is a key event that holds the four microspores together in a confined tapetal chamber, allowing them to rotate and then bind through the aperture sites through small pectin bridges, followed by joint sporopollenin deposition. Conclusion Pollen grouping could be the result of relatively minor ontogenetic changes beneficial for pollen transfer or/and protection from desiccation. Comparison of these events with those recorded in the recent pollen developmental mutants in Arabidopsis indicates that several failures during tetrad dissolution may convert to a common recurring phenotype that has evolved independently several times, whenever this grouping conferred advantages for pollen transfer. PMID:19874617

Defining pollen exposure times for clinical trials of allergen immunotherapy for pollen-induced rhinoconjunctivitis - an EAACI position paper.

PubMed

Pfaar, O; Bastl, K; Berger, U; Buters, J; Calderon, M A; Clot, B; Darsow, U; Demoly, P; Durham, S R; Galán, C; Gehrig, R; Gerth van Wijk, R; Jacobsen, L; Klimek, L; Sofiev, M; Thibaudon, M; Bergmann, K C

2017-05-01

Clinical efficacy of pollen allergen immunotherapy (AIT) has been broadly documented in randomized controlled trials. The underlying clinical endpoints are analysed in seasonal time periods predefined based on the background pollen concentration. However, any validated or generally accepted definition from academia or regulatory authorities for this relevant pollen exposure intensity or period of time (season) is currently not available. Therefore, this Task Force initiative of the European Academy of Allergy and Clinical Immunology (EAACI) aimed to propose definitions based on expert consensus. A Task Force of the Immunotherapy and Aerobiology and Pollution Interest Groups of the EAACI reviewed the literature on pollen exposure in the context of defining relevant time intervals for evaluation of efficacy in AIT trials. Underlying principles in measuring pollen exposure and associated methodological problems and limitations were considered to achieve a consensus. The Task Force achieved a comprehensive position in defining pollen exposure times for different pollen types. Definitions are presented for 'pollen season', 'high pollen season' (or 'peak pollen period') and 'high pollen days'. This EAACI position paper provides definitions of pollen exposures for different pollen types for use in AIT trials. Their validity as standards remains to be tested in future studies. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Pollen and stigma morphology of some Phaseoleae species (Leguminosae) with different pollinators.

PubMed

Basso-Alves, J P; Agostini, K; Teixeira, S de Pádua

2011-07-01

Pollen transport to a receptive stigma can be facilitated through different pollinators, which submits the pollen to different selection pressures. This study aimed to associate pollen and stigma morphology with zoophily in species of the tribe Phaseoleae. Species of the genera Erythrina, Macroptilium and Mucuna with different pollinators were chosen. Pollen grains and stigmas were examined under light microscopy (anatomy), scanning electronic microscopy (surface analyses) and transmission electronic microscopy (ultrastructure). The three genera differ in terms of pollen wall ornamentation, pollen size, pollen aperture, thickness of the pollen wall, amount of pollenkitt, pollen hydration status and dominant reserves within the pollen grain, while species within each genus are very similar in most studied characteristics. Most of these features lack relationships to pollinator type, especially in Erythrina and Mucuna. Pollen reserves are discussed on a broad scale, according to the occurrence of protein in the pollen of invertebrate- or vertebrate-pollinated species. Some pollen characteristics are more associated to semi-dry stigma requirements. This apical, compact, cuticularised and secretory stigma occurs in all species investigated. We conclude that data on pollen and stigma structure should be included together with those on floral morphology and pollinator behaviour for the establishment of functional pollination classes. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.

Pollen development in Annona cherimola Mill. (Annonaceae). Implications for the evolution of aggregated pollen.

PubMed

Lora, Jorge; Testillano, Pilar S; Risueño, Maria C; Hormaza, Jose I; Herrero, Maria

2009-10-29

In most flowering plants, pollen is dispersed as monads. However, aggregated pollen shedding in groups of four or more pollen grains has arisen independently several times during angiosperm evolution. The reasons behind this phenomenon are largely unknown. In this study, we followed pollen development in Annona cherimola, a basal angiosperm species that releases pollen in groups of four, to investigate how pollen ontogeny may explain the rise and establishment of this character. We followed pollen development using immunolocalization and cytochemical characterization of changes occurring from anther differentiation to pollen dehiscence. Our results show that, following tetrad formation, a delay in the dissolution of the pollen mother cell wall and tapetal chamber is a key event that holds the four microspores together in a confined tapetal chamber, allowing them to rotate and then bind through the aperture sites through small pectin bridges, followed by joint sporopollenin deposition. Pollen grouping could be the result of relatively minor ontogenetic changes beneficial for pollen transfer or/and protection from desiccation. Comparison of these events with those recorded in the recent pollen developmental mutants in Arabidopsis indicates that several failures during tetrad dissolution may convert to a common recurring phenotype that has evolved independently several times, whenever this grouping conferred advantages for pollen transfer.

Variability within the 10-Year Pollen Rain of a Seasonal Neotropical Forest and Its Implications for Paleoenvironmental and Phenological Research

PubMed Central

Haselhorst, Derek S.; Moreno, J. Enrique; Punyasena, Surangi W.

2013-01-01

Tropical paleoecologists use a combination of mud-water interface and modern pollen rain samples (local samples of airborne pollen) to interpret compositional changes within fossil pollen records. Taxonomic similarities between the composition of modern assemblages and fossil samples are the basis of reconstructing paleoclimates and paleoenvironments. Surface sediment samples reflect a time-averaged accumulation of pollen spanning several years or more. Due to experimental constraints, modern pollen rain samples are generally collected over shorter timeframes (1–3 years) and are therefore less likely to capture the full range of natural variability in pollen rain composition and abundance. This potentially biases paleoenvironmental interpretations based on modern pollen rain transfer functions. To determine the degree to which short-term environmental change affects the composition of the aerial pollen flux of Neotropical forests, we sampled ten years of the seasonal pollen rain from Barro Colorado Island, Panama and compared it to climatic and environmental data over the same ten-year span. We establish that the pollen rain effectively captured the strong seasonality and stratification of pollen flow within the forest canopy and that individual taxa had variable sensitivity to seasonal and annual changes in environmental conditions, manifested as changes in pollen productivity. We conclude that modern pollen rain samples capture the reproductive response of moist tropical plants to short-term environmental change, but that consequently, pollen rain-based calibrations need to include longer sampling periods (≥7 years) to reflect the full range of natural variability in the pollen output of a forest and simulate the time-averaging present in sediment samples. Our results also demonstrate that over the long-term, pollen traps placed in the forest understory are representative samples of the pollen output of both canopy and understory vegetation. Aerial pollen traps, therefore, also represent an underutilized means of monitoring the pollen productivity and reproductive behavior of moist tropical forests. PMID:23320089