The use of plant stress biomarkers in assessing the effects of desiccation in zygotic embryos from recalcitrant seeds: challenges and considerations.

PubMed

Sershen; Varghese, B; Naidoo, C; Pammenter, N W

2016-05-01

Zygotic embryos from recalcitrant seeds are sensitive to desiccation. In spite of their sensitivity, rapid partial dehydration is necessary for their successful cryopreservation. However, dehydration to water contents (WCs) that preclude lethal ice crystal formation during cooling and rewarming generally leads to desiccation damage. This study investigated the effects of rapid dehydration on selected stress biomarkers (electrolyte leakage, respiratory competence, rate of protein synthesis, superoxide production, lipid peroxidation, antioxidant activity and degree of cellular vacuolation) in zygotic embryos of four recalcitrant-seeded species. Most biomarkers indicated differences in the levels of stress/damage incurred by embryos dried to WCs < and >0.4 g·g(-1) , within species; however, these changes were often unrelated to viability and percentage water loss when data for the four species were pooled for regression analyses. Dehydration-induced electrolyte leakage was, however, positively related with percentage water loss, while biomarkers of cellular vacuolation were positively related with both percentage water loss and viability. This suggests that electrolyte leakage and degree of cellular vacuolation can be used to quantify dehydration-induced stress/damage. Biomarkers such as superoxide production, whilst useful in establishing the nature of the dehydration stress incurred may not be able to distinguish the effects of different WCs/drying times. Irrespective of which biomarker is used, the data suggest that understanding differences in desiccation sensitivity across recalcitrant-seeded species will remain a challenge unless these biomarkers are related to a generic desiccation stress index that integrates the effects of percentage water loss and drying time. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Uneven drying of zygotic embryos and embryonic axes of recalcitrant seeds: challenges and considerations for cryopreservation.

PubMed

Ballesteros, Daniel; Sershen; Varghese, Boby; Berjak, Patricia; Pammenter, Norman W

2014-08-01

Cryopreservation is the most promising option for the long-term germplasm conservation of recalcitrant-seeded species. However, the variable post-cryo success achieved with the excised zygotic explants traditionally used for cryopreservation has been a concern for some time. Differential drying rates amongst explants of different species, uneven drying amongst explants within a batch of seeds and uneven drying across tissues within individual embryos could be contributory factors to this variable success and these phenomena form the foci of the present study. Using zygotic explants from a range of recalcitrant-seeded species, which included sub-tropical dicotyledonous trees and sub-tropical monocotyledonous geophytes, the study showed that embryo morphology and anatomy are critical determinants of the drying characteristics of the different tissues composing the explant and hence, post-cryo survival. The results suggest that the rates of drying of explants to water contents (WCs) in the theoretically optimal range for successful cryopreservation are species-specific, and that more rapid drying rates may promote post-cryo survival. However, the large variation in WC amongst individual explants in bulk samples challenges the selection of the theoretically optimum WC for cryopreservation. As a consequence of differential drying rates across the different tissues composing explants, either lethal ice crystal damage or desiccation damage may sometimes be likely in tissues responsible for the onwards development of the embryo. Drying times for cryopreservation of such explants should, therefore, be selected on the basis of WC of segments containing root or shoot meristem, rather than embryo bulk WC. Drying intensity and duration also interact with explant morphology and embryo/axis size and anatomy to bring about - or preclude - post-cryo survival. Copyright © 2014 Elsevier Inc. All rights reserved.

Characterization, antioxidant activity and immunomodulatory activity of polysaccharides from the swollen culms of Zizania latifolia.

PubMed

Wang, Mingchun; Zhu, Peilei; Zhao, Shiwei; Nie, Chenzhipeng; Wang, Naifu; Du, Xianfeng; Zhou, Yibin

2017-02-01

The swollen culms of Zizania latifolia have been used as a vegetable and traditional herbal medicine in China, Japan, Korea and Southeast Asia countries. Up to date, there is little information about the polysaccharides from the swollen culms of Zizania latifolia and their potential bioactivities. In the present study, water extractable polysaccharide (ZLPs-W) and alkali extractable polysaccharide (ZLPs-A) was sequentially prepared from the swollen culms of Zizania latifolia. Both of ZLPs-W and ZLPs-A was found to be non-starch polydisperse heterpolysaccharide with β-type glycosidic linkage. ZLPs-W with triple helix conformation mainly composed of GalA, Glc and Gal. ZLPs-A without triple helix conformation mainly composed of Glc, Gal, Xyl and Ara. In in vitro antioxidant assay, ZLPs-W and ZLPs-A exhibited good scavenging activities. The EC50 of DPPH radical, superoxide radical and hydroxy radical scavenging activities for ZLPs-A is 1.87, 1.13 and 0.38mg/mL compared with that for ZLPs-W is 2.95, 3.99 and 0.5mg/mL, respectively. Moreover, in vitro cell assay revealed that ZLPs-W without cytotoxicity has higher immunomodulatory activity than ZLPs-A in terms of stimulation of phagocytic ability and NO production in murine macrophage RAW 264.7. At the treated concentration of 400μg/mL and 100μg/mL, ZLPs-W induced a highest phagocytosis index (1.76) and NO product (29.12μmol/L), respectively. The results suggest that polysaccharide from the swollen culms of Zizania latifolia could be explored as potential natural antioxidant and immunomodulatory agents in medicine or functional food fields. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in desiccating seeds of temperate and tropical forest tree species

Treesearch

K.F. Connor; F.T. Bonner; J.A. Vozzo; I. Kossman-Ferraz

2000-01-01

The physiological basis of seed recalcitrance is as yet unknown. Hypotheses suggesting possible causes have been proposed but the end result is that intact recalcitrant seeds cannot be stored for long periods of time. Thus, if the seed crop of a recalcitrant species fails, nurseries will be unable to draw upon a storage reserve of seeds in order to meet the demands of...

Population Genetic Structure of Cochliobolus miyabeanus on Cultivated Wild Rice (Zizania palustris L.) in Minnesota

USDA-ARS?s Scientific Manuscript database

Cochliobolus miyabeanus (Bipolaris oryzae) is the causal agent of fungal brown spot (FBS) in wild rice (Zizania palustris L.), an aquatic grass, endemic in Minnesota, Wisconsin, and parts of Canada. Grain yield losses can reach up to 74% when the disease starts at the boot stage and continues until ...

Population genetic structure, gene flow and recombination of Cochliobolus miyabeanus on cultivated wildrice (Zizania palustris)

USDA-ARS?s Scientific Manuscript database

Cochliobolus miyabeanus (Bipolaris oryzae) is the causal agent of fungal brown spot (FBS) in wildrice (Zizania palustris), an aquatic grass endemic to Minnesota, Wisconsin, Michigan, and parts of Canada. Grain yield losses can reach up to 74% when the disease starts at the boot stage and continues u...

Toxicity of sulfide to early life stages of wild rice (Zizania palustris).

PubMed

Fort, Douglas J; Todhunter, Kevin; Fort, Troy D; Mathis, Michael B; Walker, Rachel; Hansel, Mike; Hall, Scott; Richards, Robin; Anderson, Kurt

2017-08-01

The sensitivity of wild rice (Zizania palustris) to sulfide is not well understood. Because sulfate in surface waters is reduced to sulfide by anaerobic bacteria in sediments and historical information indicated that 10 mg/L sulfate in Minnesota (USA) surface water reduced Z. palustris abundance, the Minnesota Pollution Control Agency established 10 mg/L sulfate as a water quality criterion in 1973. A 21-d daily-renewal hydroponic study was conducted to evaluate sulfide toxicity to wild rice and the potential mitigation of sulfide toxicity by iron (Fe). The hydroponic design used hypoxic test media for seed and root exposure and aerobic headspace for the vegetative portion of the plant. Test concentrations were 0.3, 1.6, 3.1, 7.8, and 12.5 mg/L sulfide in test media with 0.8, 2.8, and 10.8 mg/L total Fe used to evaluate the impact of iron on sulfide toxicity. Visual assessments (i.e., no plants harvested) of seed activation, mesocotyl emergence, seedling survival, and phytoxicity were conducted 10 d after dark-phase exposure. Each treatment was also evaluated for time to 30% emergence (ET30), total plant biomass, root and shoot lengths, and signs of phytotoxicity at study conclusion (21 d). The results indicate that exposure of developing wild rice to sulfide at ≥3.1 mg sulfide/L in the presence of 0.8 mg/L Fe reduced mesocotyl emergence. Sulfide toxicity was mitigated by the addition of Fe at 2.8 mg/L and 10.8 mg/L relative to the control value of 0.8 mg Fe/L, demonstrating the importance of iron in mitigating sulfide toxicity to wild rice. Ultimately, determination of site-specific sulfate criteria taking into account factors that alter toxicity, including sediment Fe and organic carbon, are necessary. Environ Toxicol Chem 2017;36:2217-2226. © 2017 SETAC. © 2017 SETAC.

Genome assembly of the fungus Cochliobolus miyabeanus, and transcriptome analysis during early stages of infection on American wild rice (Zizania palustris L.)

USDA-ARS?s Scientific Manuscript database

Cochliobolus miyabeanus causes a severe, yield-reducing leaf spot disease on rice (Oryza sativa) and two North American specialty crops, American wildrice (Zizania palustris) and switchgrass (Panicum virgatum). Despite the importance of the pathogen in wildrice, little is known about mechanisms of p...

Androgenesis in recalcitrant solanaceous crops.

PubMed

Seguí-Simarro, José M; Corral-Martínez, Patricia; Parra-Vega, Verónica; González-García, Beatriz

2011-05-01

Tomato, eggplant, and pepper are three solanaceous crops of outstanding importance worldwide. For hybrid seed production in these species, a fast and cheap method to obtain pure (homozygous) lines is a priority. Traditionally, pure lines are produced by classical inbreeding and selection techniques, which are time consuming (several years) and costly. Alternatively, it has become possible to accelerate the production of homozygous lines through a biotechnological approach: the induction of androgenesis to generate doubled haploid (homozygous) plants. This biotechnological in vitro tool reduces the process to only one generation, which implies important time and costs savings. These facts make androgenic doubled haploids the choice in a number of important crops where the methodology is well set up. Unfortunately, recalcitrant solanaceous crops such as tomato, eggplant, and pepper are still far from an efficient and reliable technology to be applied on a routine basis to different genotypes in breeding programs. In eggplant and pepper, only anther cultures are known to work relatively well. Unfortunately, a more efficient and promising technique, the culture of isolated microspores, is not sufficiently developed yet. In tomato, none of these methods is available nowadays. However, recent advances in the knowledge of embryo development are filling the gaps and opening new ways to achieve the final goal of an efficient protocol in these three recalcitrant species. In this review, we outline the state of the art on androgenic induction in tomato, eggplant, and pepper, and postulate new experimental ways in order to overcome current limitations.

Germination and soil seed bank traits of Podocarpus angustifolius (Podocarpaceae): an endemic tree species from Cuban rain forests.

PubMed

Ferrandis, Pablo; Bonilla, Marta; Osorio, Licet del Carmen

2011-09-01

Podocarpus angustifolius is an endangered recalcitrant-seeded small tree, endemic to mountain rain forests in the central and Pinar del Río regions in Cuba. In this study, the germination patterns of P. angustifolius seeds were evaluated and the nature of the soil seed bank was determined. Using a weighted two-factor design, we analyzed the combined germination response to seed source (i.e. freshly matured seeds directly collected from trees versus seeds extracted from soil samples) and pretreatment (i.e. seed water-immersion for 48h at room temperature). Germination was delayed for four weeks (= 30 days) in all cases, regardless of both factors analyzed. Moreover, nine additional days were necessary to achieve high germination values (in the case of fresh, pretreated seeds). These results overall may indicate the existence of a non-deep simple morphophysiological dormancy in P. angustifolius seeds. The water-immersion significantly enhanced seed germination, probably as a result of the hydration of recalcitrant seeds. Although germination of seeds extracted from soil samples was low, probably due to aging and pathogen effects throughout the time of burial, the study revealed the existence of a persistent soil seed bank (at least short-termed) of approximately 42 viable seeds per m2 in the upper 10cm of soil. Such a record is noteworthy since references to persistent soil seed banks in recalcitrant-seeded species are scarce in the literature. The population consequences derived from the formation of persistent soil seed banks in this endangered species are discussed.

Decomposition of recalcitrant carbon under experimental warming in boreal forest

PubMed Central

Allison, Steven D.; Treseder, Kathleen K.

2017-01-01

Over the long term, soil carbon (C) storage is partly determined by decomposition rate of carbon that is slow to decompose (i.e., recalcitrant C). According to thermodynamic theory, decomposition rates of recalcitrant C might differ from those of non-recalcitrant C in their sensitivities to global warming. We decomposed leaf litter in a warming experiment in Alaskan boreal forest, and measured mass loss of recalcitrant C (lignin) vs. non-recalcitrant C (cellulose, hemicellulose, and sugars) throughout 16 months. We found that these C fractions responded differently to warming. Specifically, after one year of decomposition, the ratio of recalcitrant C to non-recalcitrant C remaining in litter declined in the warmed plots compared to control. Consistent with this pattern, potential activities of enzymes targeting recalcitrant C increased with warming, relative to those targeting non-recalcitrant C. Even so, mass loss of individual C fractions showed that non-recalcitrant C is preferentially decomposed under control conditions whereas recalcitrant C losses remain unchanged between control and warmed plots. Moreover, overall mass loss was greater under control conditions. Our results imply that direct warming effects, as well as indirect warming effects (e.g. drying), may serve to maintain decomposition rates of recalcitrant C compared to non-recalcitrant C despite negative effects on overall decomposition. PMID:28622366

Physiological, cellular and molecular aspects of the desiccation tolerance in Anadenanthera colubrina seeds during germination.

PubMed

Castro, L E; Guimarães, C C; Faria, J M R

2017-11-01

During germination, orthodox seeds become gradually intolerant to desiccation, and for this reason, they are a good model for recalcitrance studies. In the present work, physiological, biochemical, and ultrastructural aspects of the desiccation tolerance were characterized during the germination process of Anadenanthera colubrina seeds. The seeds were imbibed during zero (control), 2, 8, 12 (no germinated seeds), and 18 hours (germinated seeds with 1 mm protruded radicle); then they were dried for 72 hours, rehydrated and evaluated for survivorship. Along the imbibition, cytometric and ultrastructural analysis were performed, besides the extraction of the heat-stable proteins. Posteriorly to imbibition and drying, the evaluation of ultrastructural damages was performed. Desiccation tolerance was fully lost after root protrusion. There was no increase in 4C DNA content after the loss of desiccation tolerance. Ultrastructural characteristics of cells from 1mm roots resembled those found in the recalcitrant seeds, in both hydrated and dehydrated states. The loss of desiccation tolerance coincided with the reduction of heat-stable proteins.

Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress

PubMed Central

Colville, Louise

2012-01-01

The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography–mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:23175670

Seed birth to death: dual functions of reactive oxygen species in seed physiology.

PubMed

Jeevan Kumar, S P; Rajendra Prasad, S; Banerjee, Rintu; Thammineni, Chakradhar

2015-09-01

Reactive oxygen species (ROS) are considered to be detrimental to seed viability. However, recent studies have demonstrated that ROS have key roles in seed germination particularly in the release of seed dormancy and embryogenesis, as well as in protection from pathogens. This review considers the functions of ROS in seed physiology. ROS are present in all cells and at all phases of the seed life cycle. ROS accumulation is important in breaking seed dormancy, and stimulating seed germination and protection from pathogens. However, excessive ROS accumulation can be detrimental. Therefore, knowledge of the mechanisms by which ROS influence seed physiology will provide insights that may not only allow the development of seed quality markers but also help us understand how dormancy can be broken in several recalcitrant species. Reactive oxygen species have a dual role in seed physiology. Understanding the relative importance of beneficial and detrimental effects of ROS provides great scope for the improvement and maintenance of seed vigour and quality, factors that may ultimately increase crop yields. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of various treatments on seed germination and growth of carob (Ceratonia siliqua L.)

USDA-ARS?s Scientific Manuscript database

Carob (Ceratonia siliqua L.) plays an important role in Mediterranean landscape. It is commercially propagated by grafting which requires the generation of seedlings. However, its seeds are very recalcitrant and need pretreatment for germination. In this study, carob seeds harvested from both wild a...

A host plant genome ( Zizania latifolia ) after a century-long endophyte infection

DOE PAGES

Guo, Longbiao; Qiu, Jie; Han, Zujing; ...

2015-06-13

In spite of the importance of host–microbe interactions in natural ecosystems, agriculture and medicine, the impact of long-term (especially decades or longer) microbial colonization on the dynamics of host genomes is not well understood. Moreover, the vegetable crop ‘Jiaobai’ with enlarged edible stems was domesticated from wild Zizania latifolia (Oryzeae) approximately 2000 years ago as a result of persistent infection by a fungal endophyte, Ustilago esculenta. Asexual propagation via infected rhizomes is the only means of Jiaobai production, and the Z. latifolia–endophyte complex has been maintained continuously for two centuries. Here, genomic analysis revealed that cultivated Z. latifolia has amore » significantly smaller repertoire of immune receptors compared with wild Z. latifolia. There are widespread gene losses/mutations and expression changes in the plant–pathogen interaction pathway in Jiaobai. Finally, these results show that continuous long-standing endophyte association can have a major effect on the evolution of the structural and transcriptomic components of the host genome.« less

Ecological significance of seed desiccation sensitivity in Quercus ilex

PubMed Central

Joët, Thierry; Ourcival, Jean-Marc; Dussert, Stéphane

2013-01-01

Background and Aims Several widespread tree species of temperate forests, such as species of the genus Quercus, produce recalcitrant (desiccation-sensitive) seeds. However, the ecological significance of seed desiccation sensitivity in temperate regions is largely unknown. Do seeds of such species suffer from drying during the period when they remain on the soil, between shedding in autumn and the return of conditions required for germination in spring? Methods To test this hypothesis, the Mediterranean holm oak (Quercus ilex) forest was used as a model system. The relationships between the climate in winter, the characteristics of microhabitats, acorn morphological traits, and the water status and viability of seeds after winter were then investigated in 42 woodlands sampled over the entire French distribution of the species. Key Results The percentages of germination and normal seedling development were tightly linked to the water content of seeds after the winter period, revealing that in situ desiccation is a major cause of mortality. The homogeneity of seed response to drying suggests that neither intraspecific genetic variation nor environmental conditions had a significant impact on the level of desiccation sensitivity of seeds. In contrast, the water and viability status of seeds at the time of collection were dramatically influenced by cumulative rainfall and maximum temperatures during winter. A significant effect of shade and of the type of soil cover was also evidenced. Conclusions The findings establish that seed desiccation sensitivity is a key functional trait which may influence the success of recruitment in temperate recalcitrant seed species. Considering that most models of climate change predict changes in rainfall and temperature in the Mediterranean basin, the present work could help foresee changes in the distribution of Q. ilex and other oak species, and hence plant community alterations. PMID:23388882

Effects of some cryopreservation procedures on recalcitrant zygotic embryos of Ammocharis coranica.

PubMed

Nomali, Z; Ngobese; Sershen; Berjak, P; Pammenter, N W

2014-01-01

Cryopreservation, the most promising method for the long-term conservation of recalcitrant (desiccation-sensitive) seed germplasm, is often associated with high viability losses. Cryo-procedures involve a sequence of steps which must be optimised to reduce the impact of the stresses. This study reports on the effects of some of the steps of cryopreservation on the recalcitrant zygotic embryos of the amaryllid, Ammocharis coranica. Embryos were subjected to cryoprotection with glycerol and/or DMSO, rapid (flash) drying, and rapid (>100 degree C s(-1)) or slow (1 degree C s(-1)) cooling. Rapid dehydration (from c. 2.7 to 0.9 g g(-1) over 60 min) and cooling had a detrimental effect on the viability of the embryos, which was exacerbated when these steps were applied sequentially. After cooling, seedling production (30%) was obtained only from embryos that had been cryoprotected with glycerol prior to drying and rapid cooling, while 30% of non-treated embryos and 70% of those that had undergone cathodic protection during flash drying produced callus. Noting that no post-cryo survival of A. coranica embryos had previously been obtained, this study identified cryoprotection with glycerol and the incorporation of cathodic protection during flash drying as promising intervention points for future studies.

RNA extraction from various recalcitrant plant tissues with a cethyltrimethylammonium bromide-containing buffer followed by an acid guanidium thiocyanate-phenol-chloroform treatment.

PubMed

Suzuki, Yuji; Mae, Tadahiko; Makino, Amane

2008-07-01

High-quality total RNA was extracted using a cethyltrimethylammonium bromide-containing buffer followed by an acid guanidium thiocyanate-phenol-chloroform treatment from recalcitrant plant tissues such as tree leaves (pine, Norway spruce, ginkgo, Japanese cedar, rose), flowers (rose, Lotus japonicus) and storage tissues (seeds of Lotus japonicus and rice, sweet potato tuber, banana fruit). This protocol greatly reduced the time required for RNA extraction.

Partial dehydration and cryopreservation of Citrus seeds.

PubMed

Graiver, Natalia; Califano, Alicia; Zaritzky, Noemí

2011-11-01

Three categories of seed storage behavior are generally recognized among plant species: orthodox, intermediate and recalcitrant. Intermediate seeds cannot be stored in liquid nitrogen (LN) without a previous partial dehydration process. The water content (WC) of the seeds at the moment of immersion in LN must be regarded as the most critical factor in cryopreservation. The purpose of this study was to investigate the basis of the optimal hydration status for cryopreservation of Citrus seeds: C. sinensis (sweet orange), C. paradisi (grapefruit), C. reticulata (mandarin) in LN. To study the tolerance to dehydration and LN exposure, seeds were desiccated by equilibration at relative humidities between 11 and 95%. Sorption isotherms were determined and modeled; lipid content of the seeds was measured. Seed desiccation sensitivity was quantified by the quantal response model. Differential scanning calorimetry (DSC) thermograms were determined on cotyledon tissue at different moisture contents to measure ice melting enthalpies and unfrozen WC. Samples of total seed lipid extract were also analyzed by DSC to identify lipid transitions in the thermograms. The limit of hydration for LN Citrus seeds treatment corresponded to the unfrozen WC in the tissue, confirming that seed survival strictly depended on avoidance of intracellular ice formation. Copyright © 2011 Society of Chemical Industry.

Bioremediation and phytoremediation: Chlorinated and recalcitrant compounds

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

NONE

1998-12-31

Bioremediation and phytoremediation have progressed, especially with regard to the treatment of hydrocarbon-contaminated sites. Sites contaminated with chlorinated and recalcitrant compounds have proven more resistant to these approaches, but exciting progress is being made both in the laboratory and in the field. This book brings together the latest breakthrough thinking and results in bioremediation, with chapters on cometabolic processes, aerobic and anaerobic mechanisms, biological reductive dechlorination processes, bioaugmentation, biomonitoring, and phytoremediation of recalcitrant organic compounds.

Current understanding of the correlation of lignin structure with biomass recalcitrance

DOE PAGES

Li, Mi; Pu, Yunqiao; Ragauskas, Arthur J.

2016-11-18

Lignin, a complex aromatic polymer in terrestrial plants, contributes significantly to biomass recalcitrance to microbial and/or enzymatic deconstruction. To reduce biomass recalcitrance, substantial endeavors have been exerted on pretreatment and lignin engineering in the past few decades. Lignin removal and/or alteration of lignin structure have been shown to result in reduced biomass recalcitrance with improved cell wall digestibility. While high lignin content is usually a barrier to a cost-efficient application of bioresources to biofuels, the direct correlation of lignin structure and its concomitant properties with biomass remains unclear due to the complexity of cell wall and lignin structure. Advancement inmore » application of biorefinery to production of biofuels, chemicals, and bio-derived materials necessitates a fundamental understanding of the relationship of lignin structure and biomass recalcitrance. In this mini-review, we focus on recent investigations on the influence of lignin chemical properties on bioprocessability—pretreatment and enzymatic hydrolysis of biomass. Furthermore, lignin-enzyme interactions and the effects of lignin compositional units, hydroxycinnamates, and lignin functional groups on biomass recalcitrance have been highlighted, which will be useful not only in addressing biomass recalcitrance but also in deploying renewable lignocelluloses efficiently.« less

Current understanding of the correlation of lignin structure with biomass recalcitrance

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

Li, Mi; Pu, Yunqiao; Ragauskas, Arthur J.

Lignin, a complex aromatic polymer in terrestrial plants, contributes significantly to biomass recalcitrance to microbial and/or enzymatic deconstruction. To reduce biomass recalcitrance, substantial endeavors have been exerted on pretreatment and lignin engineering in the past few decades. Lignin removal and/or alteration of lignin structure have been shown to result in reduced biomass recalcitrance with improved cell wall digestibility. While high lignin content is usually a barrier to a cost-efficient application of bioresources to biofuels, the direct correlation of lignin structure and its concomitant properties with biomass remains unclear due to the complexity of cell wall and lignin structure. Advancement inmore » application of biorefinery to production of biofuels, chemicals, and bio-derived materials necessitates a fundamental understanding of the relationship of lignin structure and biomass recalcitrance. In this mini-review, we focus on recent investigations on the influence of lignin chemical properties on bioprocessability—pretreatment and enzymatic hydrolysis of biomass. Furthermore, lignin-enzyme interactions and the effects of lignin compositional units, hydroxycinnamates, and lignin functional groups on biomass recalcitrance have been highlighted, which will be useful not only in addressing biomass recalcitrance but also in deploying renewable lignocelluloses efficiently.« less

Natural genetic variability reduces recalcitrance in poplar

DOE PAGES

Bhagia, Samarthya; Muchero, Wellington; Kumar, Rajeev; ...

2016-05-20

Here, lignin content and structure are known to affect recalcitrance of lignocellulosic biomass to chemical/biochemical conversion. Previously, we identified rare Populus trichocarpa natural variants with significantly reduced lignin content. Because reduced lignin content may lower recalcitrance, 18 rare variants along with 4 comparators, and BESC standard Populus was analyzed for composition of structural carbohydrates and lignin. Sugar yields from these plants were measured at 5 process conditions: one for just enzymatic hydrolysis without pretreatment and four via our combined high-throughput hot water pretreatment and co-hydrolysis (HTPH) technique.

Effects of Temperature and Moisture Content on the Storability of Hardwoods Seeds

Treesearch

Kristina F. Connor; Franklin T. Bonner

1999-01-01

Experimental results have been inconclusive about low temperature storage of recalcitrant seeds from temperate zone trees. Experiments were conducted on four species of oak - chinkapin (Quercus muehlenbergii Engelm.), water (Quercus nigra L.), Shumard (Quercus shumardii Buckl.), and northern red (Quercus rubra L.). Storage temperatures were -1.5 DC and 3 DC, and...

A Tribal Story Written in Silica: Using Phytoliths to Research the Effects of Mining on Past Wild Rice (Zizania palustris) Abundance in Sandy Lake, Minnesota

NASA Astrophysics Data System (ADS)

Clarke, I. R.; Jones, M. A.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

2014-12-01

Wild rice (Zizania palustris, manoomin) is an emergent aquatic plant that grows annually in the northern Great Lakes region of North America. This region is also rich in iron ore deposits and correspondingly has an extensive history of mining activities. Wild rice no longer grows in some areas where it was previously abundant. Sandy Lake, located in St. Louis County on federally protected lands that are ceded territory of the Fond du Lac Band of Lake Superior Chippewa in Minnesota and downstream of the nearby U.S. Steel Minntac mine, was selected as a test site. This lake has a history of ricing activities by the Ojibwe (Chippewa) People, for whom manoomin has cultural importance. Lake cores were taken on June 17, 2014 by LacCore and FDLRM staff and samples were obtained. This project used phytolith analysis to answer the question of past wild rice presence and abundance in Sandy Lake. Phytoliths are microscopic opal silica deposits produced in some plants. Zizania palustris produces phytolith morphotypes that are unequivocally diagnostic of this species in this region. Microscopic slides were prepared and analyzed for wild rice phytoliths. Concentration values ranged from 25 to 4379 phytoliths per cm3/year, and wild rice accumulation figures ranged from 7 to 789 phytoliths/cm2/year, the maximum values of which occurred in the 1920s and generally declined to the current lowest levels observed. Mining has likely impacted wild rice populations by causing increased sulfate levels and possibly contributing to higher lake levels.

Temperature Responses of Soil Organic Matter Components With Varying Recalcitrance

NASA Astrophysics Data System (ADS)

Simpson, M. J.; Feng, X.

2007-12-01

The response of soil organic matter (SOM) to global warming remains unclear partly due to the chemical heterogeneity of SOM composition. In this study, the decomposition of SOM from two grassland soils was investigated in a one-year laboratory incubation at six different temperatures. SOM was separated into solvent- extractable compounds, suberin- and cutin-derived compounds, and lignin monomers by solvent extraction, base hydrolysis, and CuO oxidation, respectively. These SOM components had distinct chemical structures and recalcitrance, and their decomposition was fitted by a two-pool exponential decay model. The stability of SOM components was assessed using geochemical parameters and kinetic parameters derived from model fitting. Lignin monomers exhibited much lower decay rates than solvent-extractable compounds and a relatively low percentage of lignin monomers partitioned into the labile SOM pool, which confirmed the generally accepted recalcitrance of lignin compounds. Suberin- and cutin-derived compounds had a poor fitting for the exponential decay model, and their recalcitrance was shown by the geochemical degradation parameter which stabilized during the incubation. The aliphatic components of suberin degraded faster than cutin-derived compounds, suggesting that cutin-derived compounds in the soil may be at a higher stage of degradation than suberin- derived compounds. The temperature sensitivity of decomposition, expressed as Q10, was derived from the relationship between temperature and SOM decay rates. SOM components exhibited varying temperature responses and the decomposition of the recalcitrant lignin monomers had much higher Q10 values than soil respiration or the solvent-extractable compounds decomposition. Our study shows that the decomposition of recalcitrant SOM is highly sensitive to temperature, more so than bulk soil mineralization. This observation suggests a potential acceleration in the degradation of the recalcitrant SOM pool with global

Effects of desiccation on the recalcitrant seeds of Carapa guianensis Aubl. and Carapa procera DC

Treesearch

Kristina F. Connor; I. D. Kossmann Ferraz; F.T. Bonner; John A. Vozzo

1998-01-01

This study was undertaken to determine if the seeds of Carapa guianensis Aubl. and Carapa procera DC. undergo physiological, biochemical, and ultrastructural changes when they are desiccated; and to find if these changes can be used to monitor viability in Carapa. Seeds were air-dried at room temperature for 7 to 11 days. Samples were taken at frequent intervals and...

Mini-review: Current Understanding of the Correlation of Lignin Structure with Biomass Recalcitrance

NASA Astrophysics Data System (ADS)

Li, Mi; Pu, Yunqiao; Ragauskas, Arthur

2016-11-01

Lignin, a complex aromatic polymer in terrestrial plants, contributes significantly to biomass recalcitrance to microbial and/or enzymatic deconstruction. To reduce biomass recalcitrance, substantial endeavors have been exerted on pretreatment and lignin engineering in the past few decades. Lignin removal and/or alteration of lignin structure have been shown to result in reduced biomass recalcitrance with improved cell wall digestibility. While high lignin content is usually a barrier to a cost-efficient application of bioresource to biofuels, the direct correlation of lignin structure and its concomitant properties with biomass remains unclear due to the complexity of cell wall and lignin structure. Advancement in application of biorefinery to production of biofuels, chemicals, and biomaterials necessitates a fundamental understanding of the relationship of lignin structure and biomass recalcitrance. In this mini-review, we focus on recent investigations on the influence of lignin chemical properties on bioprocessability— pretreatment and enzymatic hydrolysis of biomass. Specifically, lignin-enzyme interaction and the effects of lignin compositional units, hydroxycinnamates, and lignin functional groups on biomass recalcitrance have been highlighted, which will be useful not only in addressing biomass recalcitrance but also in deploying renewable lignocelluloses efficiently.

Halotolerant microbial consortia able to degrade highly recalcitrant plant biomass substrate.

PubMed

Cortes-Tolalpa, Larisa; Norder, Justin; van Elsas, Jan Dirk; Falcao Salles, Joana

2018-03-01

The microbial degradation of plant-derived compounds under salinity stress remains largely underexplored. The pretreatment of lignocellulose material, which is often needed to improve the production of lignocellulose monomers, leads to high salt levels, generating a saline environment that raises technical considerations that influence subsequent downstream processes. Here, we constructed halotolerant lignocellulose degrading microbial consortia by enriching a salt marsh soil microbiome on a recalcitrant carbon and energy source, i.e., wheat straw. The consortia were obtained after six cycles of growth on fresh substrate (adaptation phase), which was followed by four cycles on pre-digested (highly-recalcitrant) substrate (stabilization phase). The data indicated that typical salt-tolerant bacteria made up a large part of the selected consortia. These were "trained" to progressively perform better on fresh substrate, but a shift was observed when highly recalcitrant substrate was used. The most dominant bacteria in the consortia were Joostella marina, Flavobacterium beibuense, Algoriphagus ratkowskyi, Pseudomonas putida, and Halomonas meridiana. Interestingly, fungi were sparsely present and negatively affected by the change in the substrate composition. Sarocladium strictum was the single fungal strain recovered at the end of the adaptation phase, whereas it was deselected by the presence of recalcitrant substrate. Consortia selected in the latter substrate presented higher cellulose and lignin degradation than consortia selected on fresh substrate, indicating a specialization in transforming the recalcitrant regions of the substrate. Moreover, our results indicate that bacteria have a prime role in the degradation of recalcitrant lignocellulose under saline conditions, as compared to fungi. The final consortia constitute an interesting source of lignocellulolytic haloenzymes that can be used to increase the efficiency of the degradation process, while decreasing

Successful treatment of recalcitrant folliculitis barbae and pseudofolliculitis barbae with photodynamic therapy.

PubMed

Diernaes, Jon Erik Fraes; Bygum, Anette

2013-12-01

Folliculitis and pseudofolliculitis barbae typically affects men with curly hair who shave too close. Treatment modalities vary in effectiveness and include improved hair removal methods, topical corticosteroids, topical and oral antibiotics, and retinoids as well as laser surgery. We report a novel treatment of recalcitrant pseudofolliculitis barbae and confirm effectiveness in recalcitrant folliculitis in a 58-year old man who responded completely following photodynamic therapy with methyl aminolevulinate. Photodynamic therapy should be considered in recalcitrant folliculitis and pseudofolliculitis barbae. Copyright © 2013 Elsevier B.V. All rights reserved.

Contribution of individual phenolics to antioxidant activity and in vitro digestibility of wild rices (Zizania aquatica L.).

PubMed

Sumczynski, Daniela; Kotásková, Eva; Orsavová, Jana; Valášek, Pavel

2017-03-01

Zizania aquatica L. was analysed for total flavonoids, phenolics and HPLC profile in both free and bound phenolic fractions. The highest content of flavonoids (378-455mgRE/kg) was detected in bound fractions, while the highest polyphenols content (1061-2988mgGAE/kg) was determined in free fractions. Additionally, predominant phenolics were identified. To understand the contribution of individual phenolics to an antioxidant activity their mutual correlations were evaluated. Regarding free flavonoids, the main contributors to an antioxidant activity (r>0.7111) were epigallocatechin, epicatechin and rutin; while epicatechin, quercetin and rutin were the main contributors in bound fractions (r>0.6868). Concerning free phenolic acids, the main contributors to an antioxidant activity (r>0.7585) were ferulic, vanillic, ellagic, sinapic and syringic acids; while caffeic, sinapic, syringic, o-coumaric, p-hydroxy benzoic, vanillic, protocatechuic, gallic and cinnamic acids were the main contributors in bound fractions of wild rice (r>0.6538). Finally, in vitro organic matter and dry matter digestibility were assessed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nanoscale Structure Of Organic Matter Explain Its Recalcitrance To Degradation

NASA Astrophysics Data System (ADS)

Spagnol, M.; Salati, S.; Papa, G.; Tambone, F.; Adani, F.

2009-04-01

Recalcitrance can be defined as the natural resistance of organic matter (OM) to microbial and enzymatic deconstruction (Himmel et al., 2007). The nature of OM recalcitrance remained not completely understood and more studies need above all to elucidate the role of the chemical topography of the OM at nanometer scale. Hydrolytic enzymes responsible of OM degradation have a molecular weight of 20-25 kD, corresponding to a size of about 4 nm, hardly penetrate into micropores (i.e. the pore having a diameter < 2 nm) and small mesopores (i.e. pores having a diameter 2 < 50 nm) of OM structures, so that their activities are confined only to a portion of the total surface (Zimmerman et al., 2004; Chesson, 1997; Adani et al., 2006). As consequence of that the characterization of the organic matter at nano-scale became interesting in view to explain OM recalcitrance. The aim of this work was to asses the effect of the nano-scale structure of OM versus its recalcitrance. The evolution of organic matter of organic matrices was studied in two systems: plant residue-soil system and simulated landfill system. Plant residues were incubated in soil for one year and recalcitrant fraction, i.e. humic acid, was isolated and studied. Laboratory simulated landfill considered organic fraction of municipal solid waste sampled at different stages of evolution from a full scale plant and incubated under anaerobic condition for one year. In addition the nano-scale structure of fossilized OM (leonardite, chair coal and graphite) was detected as used as model of recalcitrant OM. Nano-scale structures were detected by using meso and microporosity detection. In particular microporosity was determined by adsorption method using CO2 at 273 K and Non Local Density Functional Theory (NLDFT) method was applied to measure the CO2 adsorption isotherms. On the other hand mesoporosity was detected by using N2 adsorption method at 77 K. The BET (Brunauer-Emmett-Teller) equation and the BJH (Barret

Assessing the molecular structure basis for biomass recalcitrance during dilute acid and hydrothermal pretreatments

PubMed Central

2013-01-01

The production of cellulosic ethanol from biomass is considered a promising alternative to reliance on diminishing supplies of fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The conversion of lignocellulosic biomass to biofuels through a biological route usually suffers from the intrinsic recalcitrance of biomass owing to the complicated structure of plant cell walls. Currently, a pretreatment step that can effectively reduce biomass recalcitrance is generally required to make the polysaccharide fractions locked in the intricacy of plant cell walls to become more accessible and amenable to enzymatic hydrolysis. Dilute acid and hydrothermal pretreatments are attractive and among the most promising pretreatment technologies that enhance sugar release performance. This review highlights our recent understanding on molecular structure basis for recalcitrance, with emphasis on structural transformation of major biomass biopolymers (i.e., cellulose, hemicellulose, and lignin) related to the reduction of recalcitrance during dilute acid and hydrothermal pretreatments. The effects of these two pretreatments on biomass porosity as well as its contribution on reduced recalcitrance are also discussed. PMID:23356640

Biomass recalcitrance: a multi-scale, multi-factor, and conversion-specific property.

PubMed

McCann, Maureen C; Carpita, Nicholas C

2015-07-01

Recalcitrance of plant biomass to enzymatic hydrolysis for biofuel production is thought to be a property conferred by lignin or lignin-carbohydrate complexes. However, chemical catalytic and thermochemical conversion pathways, either alone or in combination with biochemical and fermentative pathways, now provide avenues to utilize lignin and to expand the product range beyond ethanol or butanol. To capture all of the carbon in renewable biomass, both lignin-derived aromatics and polysaccharide-derived sugars need to be transformed by catalysts to liquid hydrocarbons and high-value co-products. We offer a new definition of recalcitrance as those features of biomass which disproportionately increase energy requirements in conversion processes, increase the cost and complexity of operations in the biorefinery, and/or reduce the recovery of biomass carbon into desired products. The application of novel processing technologies applied to biomass reveal new determinants of recalcitrance that comprise a broad range of molecular, nanoscale, and macroscale factors. Sampling natural genetic diversity within a species, transgenic approaches, and synthetic biology approaches are all strategies that can be used to select biomass for reduced recalcitrance in various pretreatments and conversion pathways. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Photodynamic therapy: new treatment for recalcitrant Malassezia folliculitis.

PubMed

Lee, Jin Woong; Kim, Beom Joon; Kim, Myeung Nam

2010-02-01

Malassezia folliculitis commonly has been treated with oral antifungal medications. However, it has many therapeutic weaknesses such as infection relapse, drug resistance, or adverse effects like hepatotoxicity and gastrointestinal discomfort. Hence, there remains an ongoing need for alternative treatments for recalcitrant Malassezia folliculitis. Recently, many dermatologists suggest photodynamic therapy (PDT) as an alternative therapeutic option for its antimicrobial effect. To investigate the efficacy of methyl 5-aminolevulinic acid (MAL)-PDT for the treatment of recalcitrant Malassezia folliculitis. Six Korean patients aged 23-47 years with recalcitrant Malassezia folliculitis were enrolled in this study. The patients enrolled in this study either refused oral medication or were unable to take oral antifungal agents due to hepatotoxicity concerns. Thus, we offered these patients MAL-PDT as an alternative treatment option. For all patients, photographs of the lesion(s) were taken prior to initiating treatment. MAL cream (Metvix, Galderma, France) was applied to each lesion (located on the patients' trunks) and covered with an adhesive occlusive dressing polyurethane film (Tegaderm, 3M Healthcare, St. Paul, MN). After 3 hours, the cream was wiped off and illumination was performed immediately thereafter with non-coherent red light using light-emitting diodes (Aktilite lamp, PhotoCure, Oslo, Norway, average wavelength 630 nm, light dose 37 J/cm(2)). Illumination was performed for 7.5 minutes. Patients underwent totally three sessions of MAL-PDT at 2-week intervals. One month after the last PDT treatment, patients returned to the hospital and lesions were photographed. After three sessions of MAL-PDT, inflammatory lesions had decreased and improved obviously in four patients, had improved slightly in one patient, and had not improved in one patient. MAL-PDT may be an effective treatment option for patients with recalcitrant Malassezia folliculitis. However, the

Tissue-specific distribution of hemicelluloses in six different sugarcane hybrids as related to cell wall recalcitrance

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

Costa, Thales H. F.; Vega-Sánchez, Miguel E.; Milagres, Adriane M. F.

Background: Grasses are lignocellulosic materials useful to supply the billion-tons annual requirement for renewable resources that aim to produce transportation fuels and a variety of chemicals. However, the polysaccharides contained in grass cell walls are built in a recalcitrant composite. Deconstruction of these cell walls is still a challenge for the energy-efficient and economically viable transformation of lignocellulosic materials. The varied tissue-specific distribution of cell wall components adds complexity to the origins of cell wall recalcitrance in grasses. This complexity usually led to empirically developed pretreatment processes to overcome recalcitrance. A further complication is that efficient pretreatment procedures generally treatmore » the less recalcitrant tissues more than necessary, which results in the generation of undesirable biomass degradation products. Results: Six different sugarcane hybrids were used as model grasses to evaluate the tissue-specific distribution of hemicelluloses and the role of these components in cell wall recalcitrance. Acetylated glucuronoarabinoxylan (GAX) occurs in all tissues. Mixed-linkage glucan (MLG) was relevant in the innermost regions of the sugarcane internodes (up to 15.4 % w/w), especially in the low-lignin content hybrids. Immunofluorescence microscopy showed that xylans predominated in vascular bundles, whereas MLG occurred mostly in the parenchyma cell walls from the pith region of the hybrids with low-lignin content. Evaluation of the digestibility of sugarcane polysaccharides by commercial enzymes indicated that the cell wall recalcitrance varied considerably along the internode regions and in the sugarcane hybrids. Pith regions of the hybrids with high MLG and low-lignin contents reached up to 85 % cellulose conversion after 72 h of hydrolysis, without any pretreatment. Conclusions: The collective characteristics of the internode regions were related to the varied recalcitrance found in the

Tissue-specific distribution of hemicelluloses in six different sugarcane hybrids as related to cell wall recalcitrance

DOE PAGES

Costa, Thales H. F.; Vega-Sánchez, Miguel E.; Milagres, Adriane M. F.; ...

2016-05-04

Background: Grasses are lignocellulosic materials useful to supply the billion-tons annual requirement for renewable resources that aim to produce transportation fuels and a variety of chemicals. However, the polysaccharides contained in grass cell walls are built in a recalcitrant composite. Deconstruction of these cell walls is still a challenge for the energy-efficient and economically viable transformation of lignocellulosic materials. The varied tissue-specific distribution of cell wall components adds complexity to the origins of cell wall recalcitrance in grasses. This complexity usually led to empirically developed pretreatment processes to overcome recalcitrance. A further complication is that efficient pretreatment procedures generally treatmore » the less recalcitrant tissues more than necessary, which results in the generation of undesirable biomass degradation products. Results: Six different sugarcane hybrids were used as model grasses to evaluate the tissue-specific distribution of hemicelluloses and the role of these components in cell wall recalcitrance. Acetylated glucuronoarabinoxylan (GAX) occurs in all tissues. Mixed-linkage glucan (MLG) was relevant in the innermost regions of the sugarcane internodes (up to 15.4 % w/w), especially in the low-lignin content hybrids. Immunofluorescence microscopy showed that xylans predominated in vascular bundles, whereas MLG occurred mostly in the parenchyma cell walls from the pith region of the hybrids with low-lignin content. Evaluation of the digestibility of sugarcane polysaccharides by commercial enzymes indicated that the cell wall recalcitrance varied considerably along the internode regions and in the sugarcane hybrids. Pith regions of the hybrids with high MLG and low-lignin contents reached up to 85 % cellulose conversion after 72 h of hydrolysis, without any pretreatment. Conclusions: The collective characteristics of the internode regions were related to the varied recalcitrance found in the

Three-stage treatment protocol for recalcitrant distal femoral nonunion.

PubMed

Ma, Ching-Hou; Chiu, Yen-Chun; Tu, Yuan-Kun; Yen, Cheng-Yo; Wu, Chin-Hsien

2017-04-01

In this study, we proposed a three-stage treatment protocol for recalcitrant distal femoral nonunion and aimed to analyze the clinical results. We retrospective reviewed 12 consecutive patients with recalcitrant distal femoral nonunion undergoing our three-stage treatment protocol from January 2010 to December 2014 in our institute. The three-stage treatment protocol comprised debridement of the nonunion site, lengthening to eliminate leg length discrepancy, deformity correction, stabilization with a locked plate, filling of the defect with cement spacer for inducing membrane formation, and bone reconstruction using a cancellous bone autograft (Masquelet technique) or free vascularized fibular bone graft. The bone union time, wound complication, lower limbs alignment, amount of lengthening, knee range of motion, and functional outcomes were evaluated. Osseous union with angular deformity <5° and leg length discrepancy <1 cm were achieved in all the patients. The average amount of lengthening was 5.88 cm (range 3.5-12 cm). Excellent or good outcomes were obtained in 9 patients. Although the current study involved only a small number of patients and the intervention comprised three stages, we believe that such a protocol may be a valuable alternative for the treatment of recalcitrant distal femoral nonunion.

Rates of Water Loss and Uptake in Recalcitrant Fruits of Quercus Species Are Determined by Pericarp Anatomy

PubMed Central

Xia, Ke; Daws, Matthew I.; Stuppy, Wolfgang; Zhou, Zhe-Kun; Pritchard, Hugh W.

2012-01-01

Desiccation-sensitive recalcitrant seeds and fruits are killed by the loss of even moderate quantities of water. Consequently, minimizing the rate of water loss may be an important ecological factor and evolutionary driver by reducing the risk of mortality during post-dispersal dry-spells. For recalcitrant fruits of a range of Quercus species, prolonged drying times have been observed previously. However, the underlying mechanism(s) for this variation is unknown. Using nine Quercus species we investigated the major route(s) of water flow into and out of the fruits and analysed the relative importance of the different pericarp components and their anatomy on water uptake/loss. During imbibition (rehydration), the surface area of the cupule scar and the frequency and area of the vascular bundles contained therein were significantly correlated with the rates of water uptake across the scar. The vascular bundles serving the apex of the fruit were a minor contributor to overall water. Further, the rate of water uptake across the remainder of the pericarp surface was significantly correlated with the thickness of the vascularised inner layer in the pericarp. Fruits of Q. franchetii and Q. schottkyana dried most slowly and had a comparatively small scar surface area with few vascular bundles per unit area. These species inhabit drier regions than the other species studied, suggesting these anatomical features may have ecological value by reducing the risk of desiccation stress. However, this remains to be tested in the field. PMID:23071795

Investigating the Role of Extensin Proteins in Poplar Biomass Recalcitrance

DOE PAGES

Fleming, Margaret Brigham; Decker, Stephen R.; Bedinger, Patricia A.

2016-02-03

The biological conversion of cellulosic biomass to biofuel is hindered by cell wall recalcitrance, which can limit the ability of cellulases to access and break down cellulose. The purpose of this study was to investigate whether hydroxyproline-rich cell wall proteins (extensins) are present in poplar stem biomass, and whether these proteins may contribute to recalcitrance. Three classical extensin genes were identified in Populus trichocarpa through bioinformatic analysis of poplar genome sequences, with the following proposed names: PtEXTENSIN1 (Potri.001G019700); PtEXTENSIN2 (Potri.001G020100); PtEXTENSIN3 (Potri.018G050100). Tissue print immunoblots localized the extensin proteins in poplar stems to regions near the vascular cambium. Different thermochemicalmore » pretreatments reduced but did not eliminate hydroxyproline (Hyp, a proxy for extensins) from the biomass. Protease treatment of liquid hot water-pretreated poplar biomass reduced Hyp content by a further 16% and increased subsequent glucose yield by 20%. These data suggest that extensins may contribute to recalcitrance in pretreated poplar biomass, and that incorporating protease treatment into pretreatment protocols could result in a small but significant increase in the yield of fermentable glucose.« less

Compost biodegradation of recalcitrant hoof keratin by bacteria and fungi.

PubMed

Reuter, T; Gilroyed, B H; Xu, W; McAllister, T A; Stanford, K

2015-08-01

Compost activities efficiently break down a wide range of organic substances over time. In this study, bovine hoof was used as recalcitrant protein model to gain so far cryptic information on biodegradation during livestock mortalities composting. Bovine hooves (black and white), containing different amounts of melanin, placed into nylon bags were monitored during composting of cattle mortalities for up to 230 days. Besides physiochemical analysis, bacterial 16S and fungal 18S DNA fragments were amplified by PCR and profiles were separated by DGGE. Sequence analysis of separated fragments revealed various bacterial and fungal identities during composting. The microbial diversity was affected by a time-temperature interaction and by the hoof colour. Our molecular data, supported by electron microscopy, suggest hoof colonization by shifting bacteria and fungi communities. During composting, microbial communities work collaboratively in the degradation of recalcitrant organic matter such as keratin over time. A number of biomolecules including recalcitrant proteins may persist in environmental reservoirs, but breakdown can occur during composting. A combination of bioactivity and physiochemical conditions appear to be decisive for the fate of persistent biomolecules. © 2015 The Society for Applied Microbiology.

Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective

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

Gilna, Paul; Lynd, Lee R.; Mohnen, Debra

The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are then the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. Finally, we present a perspective on the aspects of successful centermore » operation.« less

Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective

DOE PAGES

Gilna, Paul; Lynd, Lee R.; Mohnen, Debra; ...

2017-11-30

The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are then the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. Finally, we present a perspective on the aspects of successful centermore » operation.« less

Study of traits and recalcitrance reduction of field-grown COMT down-regulated switchgrass

DOE PAGES

Li, Mi; Pu, Yunqiao; Yoo, Chang Geun; ...

2017-01-03

The native recalcitrance of plants hinders the biomass conversion process using current biorefinery techniques. Down-regulation of the caffeic acid O-methyltransferase (COMT) gene in the lignin biosynthesis pathway of switchgrass reduced the thermochemical and biochemical conversion recalcitrance of biomass. Due to potential environmental influences on lignin biosynthesis and deposition, studying the consequences of physicochemical changes in field-grown plants without pretreatment is essential to evaluate the performance of lignin-altered plants. In this study, we determined the chemical composition, cellulose crystallinity and the degree of its polymerization, molecular weight of hemicellulose, and cellulose accessibility of cell walls in order to better understand themore » fundamental features of why biomass is recalcitrant to conversion without pretreatment. The most important is to investigate whether traits and features are stable in the dynamics of field environmental effects over multiple years.« less

Effects of desiccation on the physiology and biochemistry of Quercus alba acorns

Treesearch

Kristina F. Connor; Sharon Sowa

2003-01-01

Seeds that lose viability when dried to a water content of less than 12% are said to be recalcitrant. We subjected acorns of Quercus alba L., a species with recalcitrant seeds, to desiccation to determine the effects of drying on lipids, proteins and carbohydrates of the embryonic axis and cotyledon tissues. Samples of fresh seed and seed dried for...

Liquid Nitrogen Cryotherapy in Recalcitrant Alopecia Areata: A Study of 11 Patients

PubMed Central

Zawar, Vijay P; Karad, Gayatri Mukund

2016-01-01

Context: Recalcitrant alopecia areata (AA) is not uncommon in clinical practice. In certain patients, treatment failures are known with almost every conventional therapy either singly or in combination. Aims: To study the efficacy of liquid nitrogen (LN) cryotherapy in patients with recalcitrant AA. Subjects and Methods: We present series of eleven patients of recalcitrant AA, who consulted us after getting no response to various modalities of treatment for 6 months. We treated them with LN cryotherapy every 2 weeks till significant hair regrowth or maximum five sittings (at 0, 2, 4, 6, and 8 weeks) whichever was earlier. Inclusion and exclusion criteria were applied. Each patient was counseled and a written consent was taken. Every session consisted of dual freeze and thaw cycles of 15 s each with a cryo unit spray. Two months of follow-up after last treatment was done to observe sustained re-growth of hair. Statistical Analysis Used: The clinical response was evaluated by using regrowth scale at 4th, 8th, and 16th week. Results: 11 patients were recruited, one patient dropped due to inability to attend follow-ups. Remaining ten patients completed the treatment and follow-up. Out of 10 patients, five patients (50%) showed an excellent response, three (30%) had a satisfactory response, one (10%) had a fair response, and one patient (10%) had a poor response. No serious adverse effects were seen. Sustained hair regrowth was seen in 80% of patients at the 16th week. Conclusions: LN cryotherapy may be worth trying treatment in the management of recalcitrant AA. PMID:27127370

A role for fruit structure in seed survival and germination of Swartzia langsdorffii Raddi beyond dispersal.

PubMed

Vaz, T A A; Rodrigues-Junior, A G; Davide, A C; Nakamura, A T; Toorop, P E

2018-03-01

Diaspore structure has been hypothesised to play a role in seed viability and/or germination of recalcitrant seeds, especially for Swartzia langsdorffii. Thus, this work aims to (i) investigate the in situ contribution of pericarp and aril on seed viability and germination, and (ii) identify morphoanatomical traits of S. langsdorffii diaspores that allow its desiccation-sensitive seeds to remain viable. The role of the pericarp and aril in seed survival and germination was investigated by placing the whole fruit, whole seeds (arillate seed) and bare seeds (without aril) in soil in the forest understorey, assessing germination, emergence, dead, firm and predated seeds, and water content of pericarps, arils and seeds. Correlation analysis was performed between environmental variables and physiological parameters. Histochemical features of diaspores were also investigated. Pericarp water content fell after several months, while the aril maintained its water content. Seeds did not lose water even without the presence of the pericarp and aril. However, presence of the pericarp promoted seed water content, viability and germination long after dispersal. The embryo had a thickened outer periclinal cell wall. Pericarp and aril are not essential to prevent water loss in seeds, but do help to retain seed moisture, favouring viability maintenance and promoting germination during the rainy season. Morphoanatomical features of seeds are suggested as main factors that reduce water loss. Survival of these desiccation-sensitive seeds upon dispersal during the dry season appears to be facilitated by multiple diaspore features that prevent viability loss. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Intracellular ice and cell survival in cryo-exposed embryonic axes of recalcitrant seeds of Acer saccharinum: an ultrastructural study of factors affecting cell and ice structures.

PubMed

Wesley-Smith, James; Berjak, Patricia; Pammenter, N W; Walters, Christina

2014-03-01

Cryopreservation is the only long-term conservation strategy available for germplasm of recalcitrant-seeded species. Efforts to cryopreserve this form of germplasm are hampered by potentially lethal intracellular freezing events; thus, it is important to understand the relationships among cryo-exposure techniques, water content, structure and survival. Undried embryonic axes of Acer saccharinum and those rapidly dried to two different water contents were cooled at three rates and re-warmed at two rates. Ultrastructural observations were carried out on radicle and shoot tips prepared by freeze-fracture and freeze-substitution to assess immediate (i.e. pre-thaw) responses to cooling treatments. Survival of axes was assessed in vitro. Intracellular ice formation was not necessarily lethal. Embryo cells survived when crystal diameter was between 0·2 and 0·4 µm and fewer than 20 crystals were distributed per μm(2) in the cytoplasm. Ice was not uniformly distributed within the cells. In fully hydrated axes cooled at an intermediate rate, the interiors of many organelles were apparently ice-free; this may have prevented the disruption of vital intracellular machinery. Intracytoplasmic ice formation did not apparently impact the integrity of the plasmalemma. The maximum number of ice crystals was far greater in shoot apices, which were more sensitive than radicles to cryo-exposure. The findings challenge the accepted paradigm that intracellular ice formation is always lethal, as the results show that cells can survive intracellular ice if crystals are small and localized in the cytoplasm. Further understanding of the interactions among water content, cooling rate, cell structure and ice structure is required to optimize cryopreservation treatments without undue reliance on empirical approaches.

A comparative study of pulsed dye laser versus long pulsed Nd:YAG laser treatment in recalcitrant viral warts.

PubMed

Shin, Yo Sup; Cho, Eun Byul; Park, Eun Joo; Kim, Kwang Ho; Kim, Kwang Joong

2017-08-01

Viral warts are common infectious skin disease induced by human papillomavirus (HPV). But the treatment of recalcitrant warts is still challenging. In this study, we compared the effectiveness of pulsed dye laser (PDL) and long pulsed Nd:YAG (LPNY) laser in the treatment of recalcitrant viral warts. We retrospectively analyzed the medical records of patients with recalcitrant warts treated with laser therapy between January 2013 and February 2016. Seventy-two patients with recalcitrant warts were evaluated. Thirty-nine patients were treated with pulsed dye laser and thirty-three patients were treated with LPNY laser. The following parameters were used: PDL (spot size, 7 mm; pulse duration, 1.5 ms; and fluence, 10-14 J/cm 2 ) and LPNY (spot size, 5 mm; pulse duration, 20 ms; and fluence, 240-300 J/cm 2 ). Complete clearance of two patients (5.1%) in PDL group, and three patients (9.1%) in LPNY group were observed without significant side effects. The patients who achieved at least 50% improvement from baseline were 20 (51.3%) in PDL and 22 (66.7%) in LPNY, respectively. This research is meaningful because we compared the effectiveness of the PDL and LPNY in the recalcitrant warts. Both PDL and LPNY laser could be used as a safe and alternative treatment for recalcitrant warts.

Arthroscopic bursectomy for recalcitrant trochanteric bursitis after hip arthroplasty.

PubMed

Van Hofwegen, Christopher; Baker, Champ L; Savory, Carlton G; Baker, Champ L

2013-01-01

This study evaluated the use of arthroscopic bursectomy for pain relief in patients with trochanteric bursitis after hip arthroplasty. In this retrospective case series of 12 patients undergoing arthroscopic treatment of recalcitrant trochanteric bursitis after hip arthroplasty, outcomes were assessed via phone interview with a numeric pain rating scale from 1 to 10 and were compared with preoperative pain ratings. Patients were asked the percentage of time they had painless hip function and whether they would have the surgery again. At an average 36-month follow-up (range, 4-85 months), the average numeric pain scale rating improved from 9.3 to 3.3. At an average of 62% of the time, patients had painless use of the hip. Ten of 12 patients in the study felt the pain relief gained was substantial enough to warrant having procedure again. In these patients, arthroscopic bursectomy was a viable option for patients with recalcitrant bursitis after hip arthroplasty.

Management of recalcitrant Trichomonas vaginalis in pregnancy: a case report.

PubMed

Tayal, Sarup

2016-02-01

A case report of a pregnant woman with recalcitrant Trichomonas vaginalis is described. This case was managed with suppressive treatment with metronidazole during pregnancy and cleared with paromomycin vaginal treatment after delivery. © The Author(s) 2015.

Impact of protective agents and drying methods on desiccation tolerance of Salix nigra L. seeds.

PubMed

Santagapita, Patricio R; Ott Schneider, Helena; Agudelo-Laverde, Lina M; Buera, M Pilar

2014-09-01

Willow seeds are classified as orthodox, but they show some recalcitrant characteristics, as they lose viability in a few weeks at room temperature. The aim of this work was to improve the desiccation tolerance of willow seeds (Salix nigra L.), as a model of sensitive materials to dehydration, through imbibition in solutions and later vacuum (VD) or freeze-drying (FD). Imbibition was conducted with 45% w/v trehalose or polyethylene glycol 400 -PEG- or water prior to dehydration treatments. Water- and especially trehalose-imbibed seeds subjected to VD showed better germination capability with respect to the freeze-dried ones. Water crystallization was mainly responsible for the great loss of capability germination observed in water- or trehalose-imbibed seeds subjected to FD. PEG behavior was better when seeds were FD instead of VD. DSC thermograms of seeds allowed to identify two thermal transitions corresponding to lipids melting and to proteins denaturation. This last transition reveals information about proteins state/functionality. Dehydration of control and PEG- or water-imbibed seeds affected proteins functionality leading to lower germinability. In the case of trehalose-imbibed seeds subjected to VD, proteins maintained their native state along dehydration, and the seeds showed a great germination capacity for all the water content range. Germinated seeds showed higher luminosity (L*), greenness (a*) and yellowness (b*) values than not-germinated seeds independently of the employed agent. Present work reveals that the presence of adequate protective agents as well the dehydration method were the main critical factors involved in willow seed desiccation tolerance. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Investigating Commercial Cellulase Performances Toward Specific Biomass Recalcitrance Factors Using Reference Substrates

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

Ju, Xiaohui; Bowden, Mark E.; Engelhard, Mark H.

Three commercial cellulase preparations, Novozymes Cellic® Ctec2, Dupont Accellerase® 1500, and DSM Cytolase CL, were evaluated for their hydrolytic activity using a set of reference biomass substrates with controlled substrate characteristics. It was found that lignin remains a significant recalcitrance factor to all the preparations, although different enzyme preparations respond to the inhibitory effect of lignin differently. Also, different types of biomass lignin can inhibit cellulose enzymes in different manners. Enhancing enzyme activity toward biomass fiber swelling is an area significantly contributing to potential improvement in cellulose performance. While the degree of polymerization of cellulose in the reference substrates didmore » not present a major recalcitrance factor to Novozymes Cellic® Ctec2, cellulose crystallite has been shown to have a significant lower reactivity toward all enzyme mixtures. The presence of polysaccharide monooxygenases (PMOs) in Novozymes Ctec2 appears to enhance enzyme activity toward decrystallization of cellulose. This study demonstrated that reference substrates with controlled chemical and physical characteristics of structural features can be applied as an effective and practical strategy to identify cellulosic enzyme activities toward specific biomass recalcitrance factor(s) and provide specific targets for enzyme improvement.« less

Investigating commercial cellulase performances toward specific biomass recalcitrance factors using reference substrates.

PubMed

Ju, Xiaohui; Bowden, Mark; Engelhard, Mark; Zhang, Xiao

2014-05-01

Three commercial cellulase preparations, Novozymes Cellic(®) Ctec2, Dupont Accellerase(®) 1500, and DSM Cytolase CL, were evaluated for their hydrolytic activity using a set of reference biomass substrates with controlled substrate characteristics. It was found that lignin remains a significant recalcitrance factor to all the preparations, although different enzyme preparations respond to the inhibitory effect of lignin differently. Also, different types of biomass lignin can inhibit cellulase enzymes in different manners. Enhancing enzyme activity toward biomass fiber swelling is an area significantly contributing to potential improvement in cellulase performance. While the degree of polymerization of cellulose in the reference substrates did not present a major recalcitrance factor to Novozymes Cellic(®) Ctec2, cellulose crystallite has been shown to have a significant lower reactivity toward all enzyme mixtures. The presence of polysaccharide monooxygenases (PMOs) in Novozymes Ctec2 appears to enhance enzyme activity toward decrystallization of cellulose. This study demonstrated that reference substrates with controlled chemical and physical characteristics of structural features can be applied as an effective and practical strategy to identify cellulosic enzyme activities toward specific biomass recalcitrance factor(s) and provide specific targets for enzyme improvement.

Working towards recalcitrance mechanisms: increased xylan and homogalacturonan production by overexpression of GAlactUronosylTransferase12 (GAUT12) causes increased recalcitrance and decreased growth in Populus

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

Biswal, Ajaya K.; Atmodjo, Melani A.; Pattathil, Sivakumar

The development of fast-growing hardwood trees as a source of lignocellulosic biomass for biofuel and biomaterial production requires a thorough understanding of the plant cell wall structure and function that underlie the inherent recalcitrance properties of woody biomass. Downregulation of GAUT12.1 in Populus deltoides was recently reported to result in improved biomass saccharification, plant growth, and biomass yield. To further understand GAUT12.1 function in biomass recalcitrance and plant growth, here we report the effects of P. trichocarpa GAUT12.1 overexpression in P. deltoides. Increasing GAUT12.1 transcript expression by 7-49% in P. deltoides PtGAUT12.1-overexpression (OE) lines resulted in a nearly complete oppositemore » biomass saccharification and plant growth phenotype to that observed previously in PdGAUT12.1-knockdown (KD) lines. This also included significantly reduced glucose, xylose, and total sugar release (12-13%), plant height (6-54%), stem diameter (8-40%), and overall total aerial biomass yield (48-61%) in 3-month-old, greenhouse-grown PtGAUT12.1-OE lines compared to controls. Total lignin content was unaffected by the gene overexpression. Importantly, selected PtGAUT12.1-OE lines retained the recalcitrance and growth phenotypes upon growth for 9 months in the greenhouse and 2.8 years in the field. PtGAUT12.1-OE plants had significantly smaller leaves with lower relative water content, and significantly reduced stem wood xylem cell numbers and size. At the cell wall level, xylose and galacturonic acid contents increased markedly in total cell walls as well as in soluble and insoluble cell wall extracts, consistent with increased amounts of xylan and homogalacturonan in the PtGAUT12.1-OE lines. This led to increased cell wall recalcitrance, as manifested by the 9-15% reduced amounts of recovered extractable wall materials and 8-15% greater amounts of final insoluble pellet in the PtGAUT12.1-OE lines compared to controls. The combined

Working towards recalcitrance mechanisms: increased xylan and homogalacturonan production by overexpression of GAlactUronosylTransferase12 (GAUT12) causes increased recalcitrance and decreased growth in Populus

DOE PAGES

Biswal, Ajaya K.; Atmodjo, Melani A.; Pattathil, Sivakumar; ...

2018-01-17

The development of fast-growing hardwood trees as a source of lignocellulosic biomass for biofuel and biomaterial production requires a thorough understanding of the plant cell wall structure and function that underlie the inherent recalcitrance properties of woody biomass. Downregulation of GAUT12.1 in Populus deltoides was recently reported to result in improved biomass saccharification, plant growth, and biomass yield. To further understand GAUT12.1 function in biomass recalcitrance and plant growth, here we report the effects of P. trichocarpa GAUT12.1 overexpression in P. deltoides. Increasing GAUT12.1 transcript expression by 7-49% in P. deltoides PtGAUT12.1-overexpression (OE) lines resulted in a nearly complete oppositemore » biomass saccharification and plant growth phenotype to that observed previously in PdGAUT12.1-knockdown (KD) lines. This also included significantly reduced glucose, xylose, and total sugar release (12-13%), plant height (6-54%), stem diameter (8-40%), and overall total aerial biomass yield (48-61%) in 3-month-old, greenhouse-grown PtGAUT12.1-OE lines compared to controls. Total lignin content was unaffected by the gene overexpression. Importantly, selected PtGAUT12.1-OE lines retained the recalcitrance and growth phenotypes upon growth for 9 months in the greenhouse and 2.8 years in the field. PtGAUT12.1-OE plants had significantly smaller leaves with lower relative water content, and significantly reduced stem wood xylem cell numbers and size. At the cell wall level, xylose and galacturonic acid contents increased markedly in total cell walls as well as in soluble and insoluble cell wall extracts, consistent with increased amounts of xylan and homogalacturonan in the PtGAUT12.1-OE lines. This led to increased cell wall recalcitrance, as manifested by the 9-15% reduced amounts of recovered extractable wall materials and 8-15% greater amounts of final insoluble pellet in the PtGAUT12.1-OE lines compared to controls. The combined

The effect of liquid hot water pretreatment on the chemical–structural alteration and the reduced recalcitrance in poplar

DOE PAGES

Li, Mi; Cao, Shilin; Meng, Xianzhi; ...

2017-11-30

Hydrothermal pretreatment using liquid hot water (LHW) is capable of substantially reducing the cell wall recalcitrance of lignocellulosic biomass. It enhances the saccharification of polysaccharides, particularly cellulose, into glucose with relatively low capital required. Due to the close association with biomass recalcitrance, the structural change of the components of lignocellulosic materials during the pretreatment is crucial to understand pretreatment chemistry and advance the bio-economy. Although the LHW pretreatment has been extensively applied and studied, the molecular structural alteration during pretreatment and its significance to reduced recalcitrance have not been well understood.

The effect of liquid hot water pretreatment on the chemical–structural alteration and the reduced recalcitrance in poplar

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

Li, Mi; Cao, Shilin; Meng, Xianzhi

Hydrothermal pretreatment using liquid hot water (LHW) is capable of substantially reducing the cell wall recalcitrance of lignocellulosic biomass. It enhances the saccharification of polysaccharides, particularly cellulose, into glucose with relatively low capital required. Due to the close association with biomass recalcitrance, the structural change of the components of lignocellulosic materials during the pretreatment is crucial to understand pretreatment chemistry and advance the bio-economy. Although the LHW pretreatment has been extensively applied and studied, the molecular structural alteration during pretreatment and its significance to reduced recalcitrance have not been well understood.

Role of endoscopy in recalcitrant intraventricular tuberculoma-innovative novel treatment adjunct.

PubMed

Udayakumaran, Suhas; Nair, Prakash; Kumar, Anil; Panikar, Dilip

2014-09-15

Introduction. Intraventricular tuberculomas are rare entities. To the best of our knowledge, only 14 cases have been reported in English literature. Medical management of cerebral tuberculomas is well accepted. Intraventricular tuberculomas may be recalcitrant for unclear reasons. An effective management protocol for this entity is unclear. To the best of our knowledge, the definitive indication, timing, and possible role of surgery in these lesions have not been discussed in literature. Materials and methods. A 27-year-old nursing professional who was undergoing treatment for miliary tuberculosis at another center presented to us in 2008 with right hemiparesis, deteriorating vision, and progressive decline in consciousness. In addition to antituberculous therapy (ATT), she underwent multiple CSF diversion procedures for the obstructive hydrocephalus secondary to a recalcitrant third ventricular tuberculoma. Finally, she underwent endoscopic decompression of the lesion with a very good clinical response at 1-year follow-up. Discussion. We discuss a patient with recalcitrant intraventricular tuberculoma managed using neuroendoscopy along with the standard antituberculous therapy. We also discuss in detail the technique we utilized for endoscopic management of this lesion. Conclusion. Being a rare entity, a consensus for management of these lesions is not possible, but we have demonstrated that neuroendoscopic management of these rare entities is an option giving the advantage of definitive diagnosis when required, hastening the resolution, and clearing the CSF pathway.

The storage capacity of cocoa seeds (Theobroma cacao L.) through giving Polyethylene Glycol (PEG) in the various of storage container

NASA Astrophysics Data System (ADS)

Lahay, R. R.; Misrun, S.; Sipayung, R.

2018-02-01

Cocoa is plant which it’s seed character is recalcitrant. Giving PEG and using various of storage containers was hoped to increase storage capacity of cocoa seeds as long as period of saving. The reseach was aimed to identify the storage capacity of cocoa seeds through giving PEG in the various of storage containers. Research took place in Hataram Jawa II, Kabupaten Simalungun, Propinsi Sumatera Utara, Indonesia. The method of this research is spit-split plot design with 3 replication. Storage period was put on main plot which was consisted of 4 level, PEG concentration was put on sub plot, consisted of 4 level and storage container was put on the sub sub plot consisted of 3 types. The results showed that until 4 days at storage with 45 % PEG concentration at all storage container, percentage of seed germination at storage can be decreased to be 2.90 %, and can be defensed until 16 days with 45 % PEG concentration at perforated plastic storage container. Percentage of molded seeds and seed moisture content were increased with added period of storage but seed moisture content was increased until 12 days at storage and was decreased at 16 days in storage.

Chemical recalcitrance of biochar and wildfire charcoal: how similar are they?

NASA Astrophysics Data System (ADS)

Santin, Cristina; Doerr, Stefan H.; Merino, Agustin

2016-04-01

The enhanced chemical resistance to biological degradation of pyrogenic materials, either produced during wildfires (charcoal) or by man (biochar), makes them long-term carbon sinks once incorporated in soils. In spite of their fundamental similarities, studies comparing the chemical recalcitrance of biochar and wildfire charcoal are scarce because analogous materials for accurate comparison are not easily available. Using solid-state 13C cross polarization-magic angle spinning nuclear magnetic resonance spectroscopy we characterized the chemical recalcitrance of pyrogenic materials generated from the same unburnt feedstooks (litter and dead wood from Pinus banksiana): (a) charcoal from a high-intensity wildfire and (b) biochar obtained by slow pyrolysis [3 treatments: 2 h at 350, 500 and 650°C]. For quantification, the spectra were divided into four regions representing different chemical environments of the 13C nucleus: alkyl C (0-45 ppm), O-alkyl C (45-110 ppm), olefinic and aromatic C(110-160 ppm), and carbonyl C (160-210 ppm). As an indicator of chemical recalcitrance, the degree of aromaticity (%) was calculated as follow: aromatic-C ∗ 100 / (alkyl C+ O alkyl-C + aromatic-C). The pyrogenic materials derived from wood show higher degrees of aromaticity (68 to 88%) than pyrogenic material derived from litter (40 to 88%). When comparing biochar and wildfire charcoal, biochars produced at 500 and 650°C always have higher degrees of aromaticity than wildfire charcoals, irrespective of the original feedstock. Wildfire charcoals always show a more heterogeneous chemical composition, with alkyl and O-alkyl compounds present even in charcoal generated at very high temperatures (temperatures up to 950 °C were recorded on the litter surface during the wildfire). However, biochars produced at 500 and 650 °C are mostly aromatic, and only the biochars produced at 350 °C show partial contribution of alkyl-C compounds. Our results suggest that biochar-type pyrogenic

Multimodal analysis of pretreated biomass species highlights generic markers of lignocellulose recalcitrance.

PubMed

Herbaut, Mickaël; Zoghlami, Aya; Habrant, Anouck; Falourd, Xavier; Foucat, Loïc; Chabbert, Brigitte; Paës, Gabriel

2018-01-01

Biomass recalcitrance to enzymatic hydrolysis has been assigned to several structural and chemical factors. However, their relative importance remains challenging to evaluate. Three representative biomass species (wheat straw, poplar and miscanthus) were submitted to four standard pretreatments (dilute acid, hot water, ionic liquid and sodium chlorite) in order to generate a set of contrasted samples. A large array of techniques, including wet chemistry analysis, porosity measurements using NMR spectroscopy, electron and fluorescence microscopy, were used in order to determine possible generic factors of biomass recalcitrance. The pretreatment conditions selected allowed obtaining samples displaying different susceptibility to enzymatic hydrolysis (from 3 up to 98% of the initial glucose content released after 96 h of saccharification). Generic correlation coefficients were calculated between the measured chemical and structural features and the final saccharification rates. Increases in porosity displayed overall strong positive correlations with saccharification efficiency, but different porosity ranges were concerned depending on the considered biomass. Lignin-related factors displayed highly negative coefficients for all biomasses. Lignin content, which is likely involved in the correlations observed for porosity, was less detrimental to enzymatic hydrolysis than lignin composition. Lignin influence was highlighted by the strong negative correlation with fluorescence intensity which mainly originates from monolignols in mature tissues. Our results provide a better understanding of the factors responsible for biomass recalcitrance that can reasonably be considered as generic. The correlations with specific porosity ranges are biomass species-dependent, meaning that enzymes cocktails with fitted enzyme size are likely to be needed to optimise saccharification depending on the biomass origin. Lignin composition, which probably influences its structure, is the

Intracellular ice and cell survival in cryo-exposed embryonic axes of recalcitrant seeds of Acer saccharinum: an ultrastructural study of factors affecting cell and ice structures

PubMed Central

Wesley-Smith, James; Berjak, Patricia; Pammenter, N. W.; Walters, Christina

2014-01-01

Background and Aims Cryopreservation is the only long-term conservation strategy available for germplasm of recalcitrant-seeded species. Efforts to cryopreserve this form of germplasm are hampered by potentially lethal intracellular freezing events; thus, it is important to understand the relationships among cryo-exposure techniques, water content, structure and survival. Methods Undried embryonic axes of Acer saccharinum and those rapidly dried to two different water contents were cooled at three rates and re-warmed at two rates. Ultrastructural observations were carried out on radicle and shoot tips prepared by freeze-fracture and freeze-substitution to assess immediate (i.e. pre-thaw) responses to cooling treatments. Survival of axes was assessed in vitro. Key Results Intracellular ice formation was not necessarily lethal. Embryo cells survived when crystal diameter was between 0·2 and 0·4 µm and fewer than 20 crystals were distributed per μm2 in the cytoplasm. Ice was not uniformly distributed within the cells. In fully hydrated axes cooled at an intermediate rate, the interiors of many organelles were apparently ice-free; this may have prevented the disruption of vital intracellular machinery. Intracytoplasmic ice formation did not apparently impact the integrity of the plasmalemma. The maximum number of ice crystals was far greater in shoot apices, which were more sensitive than radicles to cryo-exposure. Conclusions The findings challenge the accepted paradigm that intracellular ice formation is always lethal, as the results show that cells can survive intracellular ice if crystals are small and localized in the cytoplasm. Further understanding of the interactions among water content, cooling rate, cell structure and ice structure is required to optimize cryopreservation treatments without undue reliance on empirical approaches. PMID:24368198

Sulfide Generated by Sulfate Reduction is a Primary Controller of the Occurrence of Wild Rice (Zizania palustris) in Shallow Aquatic Ecosystems

NASA Astrophysics Data System (ADS)

Myrbo, A.; Swain, E. B.; Engstrom, D. R.; Coleman Wasik, J.; Brenner, J.; Dykhuizen Shore, M.; Peters, E. B.; Blaha, G.

2017-11-01

Field observations suggest that surface water sulfate concentrations control the distribution of wild rice, an aquatic grass (Zizania palustris). However, hydroponic studies show that sulfate is not toxic to wild rice at even unrealistically high concentrations. To determine how sulfate might directly or indirectly affect wild rice, potential wild rice habitat was characterized for 64 chemical and physical variables in over 100 sites spanning a relatively steep climatic and geological gradient in Minnesota. Habitat suitability was assessed by comparing the occurrence of wild rice with the field variables, through binary logistic regression. This analysis demonstrated that sulfide in sediment pore water, generated by the microbial reduction of sulfate that diffuses or advects into the sediment, is the primary control of wild rice occurrence. Water temperature and water transparency independently control the suitability of habitat for wild rice. In addition to generating phytotoxic sulfide, sulfate reduction also supports anaerobic decomposition of organic matter, releasing nutrients that can compound the harm of direct sulfide toxicity. These results are important because they show that increases in sulfate loading to surface water can have multiple negative consequences for ecosystems, even though sulfate itself is relatively benign.

Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

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

Alcantara, Maria Angeles Bermudez; Dobruchowska, Justyna; Azadi, Parastoo

To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw.more » On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.« less

Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

DOE PAGES

Alcantara, Maria Angeles Bermudez; Dobruchowska, Justyna; Azadi, Parastoo; ...

2016-10-06

To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw.more » On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.« less

Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass.

PubMed

Alcántara, María Ángeles Bermúdez; Dobruchowska, Justyna; Azadi, Parastoo; García, Bruno Díez; Molina-Heredia, Fernando P; Reyes-Sosa, Francisco Manuel

2016-01-01

To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. Two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. This suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.

Investigating the role of extensin proteins in poplar biomass recalcitrance

USDA-ARS?s Scientific Manuscript database

The biological conversion of cellulosic biomass to biofuel is hindered by cell wall recalcitrance, which can limit the ability of cellulases to access and break down cellulose. The purpose of this study was to investigate whether hydroxyproline-rich cell wall proteins (extensins) are present in popl...

Warming Rather Than Increased Precipitation Increases Soil Recalcitrant Organic Carbon in a Semiarid Grassland after 6 Years of Treatments

PubMed Central

Zhou, Xiaoqi; Chen, Chengrong; Wang, Yanfen; Smaill, Simeon; Clinton, Peter

2013-01-01

Improved understanding of changes in soil recalcitrant organic carbon (C) in response to global warming is critical for predicting changes in soil organic C (SOC) storage. Here, we took advantage of a long-term field experiment with increased temperature and precipitation to investigate the effects of warming, increased precipitation and their interactions on SOC fraction in a semiarid Inner Mongolian grassland of northern China since April 2005. We quantified labile SOC, recalcitrant SOC and stable SOC at 0–10 and 10–20 cm depths. Results showed that neither warming nor increased precipitation affected total SOC and stable SOC at either depth. Increased precipitation significantly increased labile SOC at the 0–10 cm depth. Warming decreased labile SOC (P = 0.038) and marginally but significantly increased recalcitrant SOC at the 10–20 cm depth (P = 0.082). In addition, there were significant interactive effects of warming and increased precipitation on labile SOC and recalcitrant SOC at the 0–10 cm depth (both P<0.05), indicating that that results from single factor experiments should be treated with caution because of multi-factor interactions. Given that the absolute increase of SOC in the recalcitrant SOC pool was much greater than the decrease in labile SOC, and that the mean residence time of recalcitrant SOC is much greater, our results suggest that soil C storage at 10–20 cm depth may increase with increasing temperature in this semiarid grassland. PMID:23341995

Intralesional vincristine combined with cryotherapy for recalcitrant verrucas.

PubMed

Lee, Jong-Rok; Youn, Jeong-Hwan; Roh, Joo-Young

2011-01-01

Verrucas are often recalcitrant to conventional cryotherapy. Since 1970, intralesional bleomycin has been used off-label by dermatologists. But in some cases, the results of intralesional bleomycin were disappointing. Vincristine is a well-known vinca alkaloid antiblastic drug that has been used for treating hematological neoplasm and nephroblastomas. It was reported good efficacy of intralesional vincristine for treating nodular lesion in classic Kaposi sarcoma. Its use in epithelial neoplasm and Kaposi sarcoma may support its efficacy in recalcitrant verrucas. The three patients selected for the study presented severe verrucas on foot, and they had already undergone cryotherapy several times and there was no improvement. They got intralesional vincristine injection on their verrucas. The target lesion was infiltrated with 0.03 mL of vincristine sulphate at a concentration of 1 µg/mL. The injected amount of vincristine was proportional to the diameter of the nodule. After two treatments had been completed, there was a great decrease of lesion size compared with the other lesions. The three patients complained of pain lasting for several days. This pain was generally well tolerated. Intralesional vincristine injection on verruca is an effective and rapid novel method, and when combined with cryotherapy, shows excellent therapeutic response. © 2011 Wiley Periodicals, Inc.

Hybrid biological, electron beam and zero-valent nano iron treatment of recalcitrant metalworking fluids.

PubMed

Thill, Patrick G; Ager, Duane K; Vojnovic, Borivoj; Tesh, Sarah J; Scott, Thomas B; Thompson, Ian P

2016-04-15

Hybrid approaches for the remediation and detoxification of toxic recalcitrant industrial wastewater were investigated. The focus was waste metalworking fluid, which was selected as a representative model of other waste streams that are toxic, recalcitrant and that require more sustainable routes of safe disposal. The hybrid approaches included biodegradation, electron beam irradiation and zero-valent nano iron advanced oxidation processes that were employed individually and in sequence employing a factorial design. To compare process performance operationally exhausted and pristine metalworking fluid were compared. Sequential hybrid electron beam irradiation, biological, nanoscale zero-valent iron and biological treatment lead to synergistic detoxification and degradation of both recalcitrant streams, as determined by complementary surrogates and lead to overall improved COD removal of 92.8 ± 1.4% up from 85.9 ± 3.4% for the pristine metalworking fluid. Electron beam pre-treatment enabled more effective biotreatment, achieving 69.5 ± 8% (p = 0.005) and 24.6 ± 4.8% (p = 0.044) COD reductions. Copyright © 2016. Published by Elsevier Ltd.

[Application of cantharidin, podophyllotoxin, and salicylic acid in recalcitrant plantar warts. A preliminary study].

PubMed

López-López, Daniel; Agrasar-Cruz, Carlos; Bautista-Casasnovas, Adolfo; Álvarez-Castro, Carlos Javier

2015-01-01

Plantar warts often are refractory to any treatment and can last for decades in adults. Recalcitrant warts are defined as those that have persisted for more than two years, or after at least two treatment modalities. A total of 15 consecutive patients with recalcitrant plantar warts were included in this preliminary study. The treatment consisted of applying one to two sessions that comprised compounding 1% cantharidin, 5% of podophyllotoxin, and 30% salicylic acid (CPS), with an interval between applications of four weeks. With treatment and subsequent follow-up for six months, there was complete eradication of lesions in 15 patients, eight (53.3%) required a single application of the solution, and seven (46.7%) two applications, with no side effects. Patient satisfaction related to treatment was measured by a visual analog scale (VAS) of 10 cm in length, with an average score 9.73 ± 0.46, and all said they would proceed with the treatment again if necessary. Topical treatment by compounding is safe, effective, and a promising therapeutic modality when applied in recalcitrant plantar warts.

Genetic manipulation of lignin reduces recalcitrance and improves ethanol production from switchgrass

PubMed Central

Fu, Chunxiang; Mielenz, Jonathan R.; Xiao, Xirong; Ge, Yaxin; Hamilton, Choo Y.; Rodriguez, Miguel; Chen, Fang; Foston, Marcus; Ragauskas, Arthur; Bouton, Joseph; Dixon, Richard A.; Wang, Zeng-Yu

2011-01-01

Switchgrass is a leading dedicated bioenergy feedstock in the United States because it is a native, high-yielding, perennial prairie grass with a broad cultivation range and low agronomic input requirements. Biomass conversion research has developed processes for production of ethanol and other biofuels, but they remain costly primarily because of the intrinsic recalcitrance of biomass. We show here that genetic modification of switchgrass can produce phenotypically normal plants that have reduced thermal-chemical (≤180 °C), enzymatic, and microbial recalcitrance. Down-regulation of the switchgrass caffeic acid O-methyltransferase gene decreases lignin content modestly, reduces the syringyl:guaiacyl lignin monomer ratio, improves forage quality, and, most importantly, increases the ethanol yield by up to 38% using conventional biomass fermentation processes. The down-regulated lines require less severe pretreatment and 300–400% lower cellulase dosages for equivalent product yields using simultaneous saccharification and fermentation with yeast. Furthermore, fermentation of diluted acid-pretreated transgenic switchgrass using Clostridium thermocellum with no added enzymes showed better product yields than obtained with unmodified switchgrass. Therefore, this apparent reduction in the recalcitrance of transgenic switchgrass has the potential to lower processing costs for biomass fermentation-derived fuels and chemicals significantly. Alternatively, such modified transgenic switchgrass lines should yield significantly more fermentation chemicals per hectare under identical process conditions. PMID:21321194

Robotic Y-V Plasty for Recalcitrant Bladder Neck Contracture.

PubMed

Granieri, Michael A; Weinberg, Aaron C; Sun, Jeffrey Y; Stifleman, Michael; Zhao, Lee

2018-07-01

To demonstrate the technique and the outcomes of robot assisted Y-V plasty bladder neck reconstruction (RYVBNR). We present our technique for treatment of recalcitrant bladder neck contracture (BNC) in 7 patients who underwent RYVBNR at our institution between March 2016 and September 2017. Indication for the procedure was incomplete emptying, recurrent urinary tract infections, and dysuria. On follow-up, patients were assessed for clinical success by absence of infections, symptoms, and cystoscopic evaluation. Robotic assisted dissection is performed to open the space of Retzius and mobilize the bladder. The cystoscope is passed to the level of the BNC, and Firefly technology is used to localize the BNC. The BNC is incised anteriorly, and a V-shaped bladder flap is advanced into the BNC in a Y-V plasty fashion. We place a perioperative closed suction drain, which is removed before discharge, and a 22 Fr catheter, which that will be removed in the office at approximately 2 weeks. Six men developed recalcitrant BNCs and 1 developed a recalcitrant vesicourethral anastomotic stenosis. All patients had previously undergone an endoscopic procedure. Median time for last attempt at endoscopic management to robot-assisted bladder neck repair was 4.7 months. The average number of prior attempts at endoscopic management was 2. All patients underwent RYVBNR without conversion to open surgery. The median operative time was 240 minutes, estimated blood loss was 67 mL, and length of stay was 1 day. There were no intraoperative complications. Catheters were removed in the office at a median time of 15 days. At a median follow-up of 8 months, all cases were successful with no evidence of recurrence. Only 2 patients had persistent urinary incontinence at 1 pad per day. RYVBNR with a Y-V plasty is a feasible and effective technique for managing a difficult reconstructive problem. Copyright © 2018 Elsevier Inc. All rights reserved.

Agave proves to be a low recalcitrant lignocellulosic feedstock for biofuels production on semi-arid lands.

PubMed

Li, Hongjia; Pattathil, Sivakumar; Foston, Marcus B; Ding, Shi-You; Kumar, Rajeev; Gao, Xiadi; Mittal, Ashutosh; Yarbrough, John M; Himmel, Michael E; Ragauskas, Arthur J; Hahn, Michael G; Wyman, Charles E

2014-01-01

Agave, which is well known for tequila and other liquor production in Mexico, has recently gained attention because of its attractive potential to launch sustainable bioenergy feedstock solutions for semi-arid and arid lands. It was previously found that agave cell walls contain low lignin and relatively diverse non-cellulosic polysaccharides, suggesting unique recalcitrant features when compared to conventional C4 and C3 plants. Here, we report sugar release data from fungal enzymatic hydrolysis of non-pretreated and hydrothermally pretreated biomass that shows agave to be much less recalcitrant to deconstruction than poplar or switchgrass. In fact, non-pretreated agave has a sugar release five to eight times greater than that of poplar wood and switchgrass . Meanwhile, state of the art techniques including glycome profiling, nuclear magnetic resonance (NMR), Simon's Stain, confocal laser scanning microscopy and so forth, were applied to measure interactions of non-cellulosic wall components, cell wall hydrophilicity, and enzyme accessibility to identify key structural features that make agave cell walls less resistant to biological deconstruction when compared to poplar and switchgrass. This study systematically evaluated the recalcitrant features of agave plants towards biofuels applications. The results show that not only does agave present great promise for feeding biorefineries on semi-arid and arid lands, but also show the value of studying agave's low recalcitrance for developments in improving cellulosic energy crops.

Differential growth responses of soil bacterial taxa to carbon substrates of varying chemical recalcitrance

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

Goldfarb, K.C.; Karaoz, U.; Hanson, C.A.

2011-04-18

Soils are immensely diverse microbial habitats with thousands of co-existing bacterial, archaeal, and fungal species. Across broad spatial scales, factors such as pH and soil moisture appear to determine the diversity and structure of soil bacterial communities. Within any one site however, bacterial taxon diversity is high and factors maintaining this diversity are poorly resolved. Candidate factors include organic substrate availability and chemical recalcitrance, and given that they appear to structure bacterial communities at the phylum level, we examine whether these factors might structure bacterial communities at finer levels of taxonomic resolution. Analyzing 16S rRNA gene composition of nucleotide analog-labeledmore » DNA by PhyloChip microarrays, we compare relative growth rates on organic substrates of increasing chemical recalcitrance of >2,200 bacterial taxa across 43 divisions/phyla. Taxa that increase in relative abundance with labile organic substrates (i.e., glycine, sucrose) are numerous (>500), phylogenetically clustered, and occur predominantly in two phyla (Proteobacteria and Actinobacteria) including orders Actinomycetales, Enterobacteriales, Burkholderiales, Rhodocyclales, Alteromonadales, and Pseudomonadales. Taxa increasing in relative abundance with more chemically recalcitrant substrates (i.e., cellulose, lignin, or tannin-protein) are fewer (168) but more phylogenetically dispersed, occurring across eight phyla and including Clostridiales, Sphingomonadalaes, Desulfovibrionales. Just over 6% of detected taxa, including many Burkholderiales increase in relative abundance with both labile and chemically recalcitrant substrates. Estimates of median rRNA copy number per genome of responding taxa demonstrate that these patterns are broadly consistent with bacterial growth strategies. Taken together, these data suggest that changes in availability of intrinsically labile substrates may result in predictable shifts in soil bacterial

Visualising recalcitrance by colocalisation of cellulase, lignin and cellulose in pretreated pine biomass using fluorescence microscopy

NASA Astrophysics Data System (ADS)

Donaldson, Lloyd; Vaidya, Alankar

2017-03-01

Mapping the location of bound cellulase enzymes provides information on the micro-scale distribution of amenable and recalcitrant sites in pretreated woody biomass for biofuel applications. The interaction of a fluorescently labelled cellulase enzyme cocktail with steam-exploded pine (SEW) was quantified using confocal microscopy. The spatial distribution of Dylight labelled cellulase was quantified relative to lignin (autofluorescence) and cellulose (Congo red staining) by measuring their colocalisation using Pearson correlations. Correlations were greater in cellulose-rich secondary cell walls compared to lignin-rich middle lamella but with significant variations among individual biomass particles. The distribution of cellulose in the pretreated biomass accounted for 30% of the variation in the distribution of enzyme after correcting for the correlation between lignin and cellulose. For the first time, colocalisation analysis was able to quantify the spatial distribution of amenable and recalcitrant sites in relation to the histochemistry of cellulose and lignin. This study will contribute to understanding the role of pretreatment in enzymatic hydrolysis of recalcitrant softwood biomass.

Significance of Lignin S/G Ratio in Biomass Recalcitrance of Populus trichocarpa Variants for Bioethanol Production

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

Yoo, Chang Geun; Dumitrache, Alexandru; Muchero, Wellington

Lignin S/G ratio has been investigated as an important factor in biomass recalcitrance to bioethanol production. Because of the complexity and variety of biomass, recalcitrance was also reportedly influenced by several other factors, such as total lignin content, degree of cellulose polymerization, etc. In addition, the effect of S/G ratio on biomass conversion is not uniform across plant species. Herein, 11 Populus trichocarpa natural variants grown under the same conditions with similar total lignin content were selected to minimize the effects of other factors. The lignin S/G ratio of the selected P. trichocarpa natural variants showed negative correlations with p-hydroxybenzoatemore » (PB) and ..beta..-5 linkage contents, while it had positive ones with ..beta..-O-4 linkage, lignin molecular weight, and ethanol production. This study showed the importance of lignin S/G ratio as an independent recalcitrance factor that may aid future energy crop engineering and biomass conversion strategies.« less

Significance of Lignin S/G Ratio in Biomass Recalcitrance of Populus trichocarpa Variants for Bioethanol Production

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

Yoo, Chang Geun; Dumitrache, Alexandru; Muchero, Wellington

Lignin S/G ratio has been investigated as an important factor in biomass recalcitrance to bioethanol production. Because of the complexity and variety of biomass, recalcitrance was also reportedly influenced by several other factors, such as total lignin content, degree of cellulose polymerization, etc. In addition, the effect of S/G ratio on biomass conversion is not uniform across plant species. Herein, 11 Populus trichocarpa natural variants grown under the same conditions with similar total lignin content were selected to minimize the effects of other factors. The lignin S/G ratio of the selected P. trichocarpa natural variants showed negative correlations with p-hydroxybenzoatemore » (PB) and β–5 linkage contents, while it had positive ones with β-O-4 linkage, lignin molecular weight, and ethanol production. In conclusion, this study showed the importance of lignin S/G ratio as an independent recalcitrance factor that may aid future energy crop engineering and biomass conversion strategies.« less

Agave proves to be a low recalcitrant lignocellulosic feedstock for biofuels production on semi-arid lands

PubMed Central

2014-01-01

Background Agave, which is well known for tequila and other liquor production in Mexico, has recently gained attention because of its attractive potential to launch sustainable bioenergy feedstock solutions for semi-arid and arid lands. It was previously found that agave cell walls contain low lignin and relatively diverse non-cellulosic polysaccharides, suggesting unique recalcitrant features when compared to conventional C4 and C3 plants. Results Here, we report sugar release data from fungal enzymatic hydrolysis of non-pretreated and hydrothermally pretreated biomass that shows agave to be much less recalcitrant to deconstruction than poplar or switchgrass. In fact, non-pretreated agave has a sugar release five to eight times greater than that of poplar wood and switchgrass . Meanwhile, state of the art techniques including glycome profiling, nuclear magnetic resonance (NMR), Simon’s Stain, confocal laser scanning microscopy and so forth, were applied to measure interactions of non-cellulosic wall components, cell wall hydrophilicity, and enzyme accessibility to identify key structural features that make agave cell walls less resistant to biological deconstruction when compared to poplar and switchgrass. Conclusions This study systematically evaluated the recalcitrant features of agave plants towards biofuels applications. The results show that not only does agave present great promise for feeding biorefineries on semi-arid and arid lands, but also show the value of studying agave’s low recalcitrance for developments in improving cellulosic energy crops. PMID:24708685

An Index-Based Approach to Assessing Recalcitrance and Soil Carbon Sequestration Potential of Engineered Black Carbons (Biochars)

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

Harvey, Omar R.; Kuo, Li-Jung; Zimmerman, Andrew R.

2012-01-10

The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R{sub 50}, for assessing biochar quality for carbon sequestration is proposed. The R{sub 50} is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R{sub 50}, with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiablemore » relationship between R{sub 50} and biochar recalcitrance. As presented here, the R{sub 50} is immediately applicable to pre-land application screening of biochars into Class A (R{sub 50} {>=} 0.70), Class B (0.50 {<=} R{sub 50} < 0.70) or Class C (R{sub 50} < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, while Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R{sub 50}, to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars.« less

Ultrasound-Guided Pulsed Radiofrequency Stimulation of Posterior Tibial Nerve: A Potential Novel Intervention for Recalcitrant Plantar Fasciitis.

PubMed

Wu, Yung-Tsan; Chang, Chih-Ya; Chou, Yu-Ching; Yeh, Chun-Chang; Li, Tsung-Ying; Chu, Heng-Yi; Chen, Liang-Cheng

2017-05-01

To evaluate the therapeutic benefit of ultrasound-guided pulsed radiofrequency (PRF) stimulation at the posterior tibial nerve (PTN) in patients with recalcitrant plantar fasciitis (PF). A prospective, randomized, double-blinded, placebo-controlled trial (12-wk follow-up). Outpatient local medical center settings. Patients (N=36) with recalcitrant PF underwent randomization, and all were included in the final data analysis. Patients in the PRF group were treated with 1 dose of ultrasound-guided PRF stimulation at the PTN, and those in the control group received 1 dose of 2% lidocaine, 0.5mL, injected at the PTN under ultrasound guidance. The visual analog scale (first-step and overall pain), American Orthopedic Foot-Ankle Society (AOFAS) ankle-hindfoot scale, and ultrasonographic thickness of the plantar fascia were evaluated at 1, 4, 8, and 12 weeks after treatment. Thirty-six patients (20 feet per group) completed the study. The PRF group had a significantly larger improvement in first-step pain, overall pain, and AOFAS score (all P<.001), as well as plantar fascia thickness (P<.05), compared with those of the control group at all observed time points. This study shows that ultrasound-guided PRF stimulation at the PTN is effective for treating recalcitrant PF. This simple, reproducible method could be a novel strategy for managing recalcitrant PF. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Pretreatment of woody biomass for biofuel production: energy efficiency, technologies, and recalcitrance

Treesearch

J.Y. Zhu; Xuejun Pan; Ronald S. Jr. Zalesny

2010-01-01

This mini review discusses several key technical issues associated with cellulosic ethanol production from woody biomass: energy consumption for woody biomass pretreatment, pretreatment energy efficiency, woody biomass pretreatment technologies, and quantification of woody biomass recalcitrance. Both total sugar yield and pretreatment energy efficiency, defined as the...

Potential for enhancement of aerobic biological removal of recalcitrant organic matter in bleached pulp mill effluents.

PubMed

Mounteer, A H; Souza, L C; Silva, C M

2007-02-01

Increasingly stringent effluent quality limits for bleached kraft pulp mills pose a great challenge to mill wastewater system managers since these limits can require levels of chemical oxygen demand (COD) removal efficiency rarely reported for biological treatment of these types of effluents. The present study was therefore undertaken to better understand the nature of recalcitrant COD in bleached kraft pulp effluents that persists through the biological treatment system. Bleaching effluents from a Brazilian eucalypt bleached kraft pulp mill were collected and treated in a bench-scale sequencing batch reactor. Organic matter in raw and treated effluents was characterized before and after separation into low and high molecular mass fractions. Biological treatment removed 71% of the COD, with 83% removal of the low molecular mass COD but only 36% removal of the high molecular mass COD. Microorganisms capable of degrading the recalcitrant COD were isolated from enrichment cultures of the original activated sludge fed on fractions of the bleaching effluent that presented low biodegradabilities. Use of a microbial consortium composed of ten of these isolates to treat the biologically treated effluent removed a further 12% of the effluent COD, all from the high molecular mass fraction. Results of this research indicate that microorganisms with potential for degrading recalcitrant COD are present in activated sludge, but that these are not metabolically active during normal activated sludge treatment of mill effluents. The use of biological selectors in the treatment system to promote growth of such microorganisms may enhance removal of recalcitrant organic matter.

Why is intracellular ice lethal? A microscopical study showing evidence of programmed cell death in cryo-exposed embryonic axes of recalcitrant seeds of Acer saccharinum

PubMed Central

Wesley-Smith, James; Walters, Christina; Pammenter, N. W.

2015-01-01

Background and Aims Conservation of the genetic diversity afforded by recalcitrant seeds is achieved by cryopreservation, in which excised embryonic axes (or, where possible, embryos) are treated and stored at temperatures lower than −180 °C using liquid nitrogen. It has previously been shown that intracellular ice forms in rapidly cooled embryonic axes of Acer saccharinum (silver maple) but this is not necessarily lethal when ice crystals are small. This study seeks to understand the nature and extent of damage from intracellular ice, and the course of recovery and regrowth in surviving tissues. Methods Embryonic axes of A. saccharinum, not subjected to dehydration or cryoprotection treatments (water content was 1·9 g H2O g−1 dry mass), were cooled to liquid nitrogen temperatures using two methods: plunging into nitrogen slush to achieve a cooling rate of 97 °C s−1 or programmed cooling at 3·3 °C s−1. Samples were thawed rapidly (177 °C s−1) and cell structure was examined microscopically immediately, and at intervals up to 72 h in vitro. Survival was assessed after 4 weeks in vitro. Axes were processed conventionally for optical microscopy and ultrastructural examination. Key Results Immediately following thaw after cryogenic exposure, cells from axes did not show signs of damage at an ultrastructural level. Signs that cells had been damaged were apparent after several hours of in vitro culture and appeared as autophagic decomposition. In surviving tissues, dead cells were sloughed off and pockets of living cells were the origin of regrowth. In roots, regrowth occurred from the ground meristem and procambium, not the distal meristem, which became lethally damaged. Regrowth of shoots occurred from isolated pockets of surviving cells of peripheral and pith meristems. The size of these pockets may determine the possibility for, the extent of and the vigour of regrowth. Conclusions Autophagic degradation and ultimately autolysis of cells following

Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust enzymatic saccharification of hardwoods

Treesearch

G. S. Wang; X. J. Pan; Junyong Zhu; Roland Gleisner; D. Rockwood

2009-01-01

This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180[...

Metabolic and structural changes during early maturation of Inga vera seeds are consistent with the lack of a desiccation phase.

PubMed

Caccere, Rodrigo; Teixeira, Simone P; Centeno, Danilo C; Figueiredo-Ribeiro, Rita de Cássia L; Braga, Márcia R

2013-06-15

Inga vera, native to South America, is an important leguminous species used for ecological restoration of riparian forests and its seeds are among the most recalcitrant ones described up to date. In this work, we analysed the metabolic profile, cell ultrastructure as well as cell wall polysaccharides of I. vera seeds in order to better understand its maturation, which allows embryo germination without a quiescent phase. Increased amounts of citric, glutamic, pyroglutamic, and aspartic acids from stages I to II (120 and 129 days after flowering (DAF)) corroborate the hypothesis of high metabolism, shifting from fermentative to aerobic respiration at seed maturity. This phase was characterized by an extensive vacuolization of embryonic cells, which also indicate high metabolic activity. The proportion of arabinose in the cell walls of embryonic axis (approx. 20%) was lower than those found in some orthodox seeds (nearly 40%), suggesting that arabinose-containing polysaccharides, which are thought to provide more flexibility to the cell wall during natural drying, are less abundant in I. vera seeds. Taken together, our results provide evidence that the major changes occurred during early stages of seed maturation of I. vera, indicating that the rapid temporary metabolic shift observed between stages I and II may be related to the lack of desiccation phase, moving directly to germination. Copyright © 2013 Elsevier GmbH. All rights reserved.

Application of neem (Azadirachta indica) as biological pesticides in cocoa seed (Theobroma cacao) storage using various local adsorbent media

NASA Astrophysics Data System (ADS)

Mardiyani, S. A.; Sunawan; Pawestri, A. E.

2018-03-01

Cocoa seeds are recalcitrant (the water content is more than 40%) that require special handling. The use of adsorbent media to reduce the decrease in the quality of cocoa seeds and extend their shelf life in this storage has not been widely done. Local adsorbent media such as sawdust, sand and ash have the potential to maintain the viability of cocoa seeds. The objective of this research was to determine the interaction of the application of neem (Azadirachta indica) as biological pesticides and the use of various natural adsorbent media in the storage of cocoa seeds (Theobroma cacao). It was an experimental study with a factorial design composed of three factors. The first factor was the medium adsorbent type for the storage of cocoa seed, which consists of three levels (river sand, ash, and sawdust). The second factor was the concentration of neem leaves for pre-storage treatment with three levels (10, 20, and 30%). The third factor was the storage time (10 and 20 days). The results of the study indicated that the combination of the three factors showed a significant interaction in the height of the plant and the diameter of the stem of the seedling at 28 days after sowing. The fresh weight of the seedlings of the seeds that were stored in ash media gave a better result than the seedlings of seeds that had been stored in the river sand and the sawdust as adsorbent media. The application of 20% extract of neem leaves gave the best influence for the seeds that were stored for 20 days.

Relationship of Plantar Fascia Thickness and Preoperative Pain, Function, and Quality of Life in Recalcitrant Plantar Fasciitis.

PubMed

Gamba, Carlo; Sala-Pujals, Aleix; Perez-Prieto, Daniel; Ares-Vidal, Jesus; Solano-Lopez, Alberto; Gonzalez-Lucena, Gemma; Ginés-Caspedosa, Alberto

2018-04-01

The measurement of plantar fascia thickness has been advocated as a diagnostic and prognostic instrument in patients with plantar fasciitis, but there are no data relative to it in recalcitrant plantar fasciitis. The aim of the study is to evaluate the correlation between plantar fascia thickness and pain, functional score, and health perception in patients with this condition. Thirty-eight feet were studied with ultrasound and magnetic resonance imaging to measure plantar fascia thickness. The visual analogue scale (VAS), American Orthopaedic Foot & Ankle Hindfoot Score (AOFAS), and SF-36 were then recorded for each patient. The relationship between the fascia and these scores was analyzed to evaluate the correlation of thickness with pain, functional level, and health perception of patients. In patients with recalcitrant plantar fasciitis, plantar fascia thickness did not correlate with pain (VAS), AOFAS, or any item of the SF-36. The thickness of the plantar fascia in patients with recalcitrant plantar fasciitis did not correlate with its clinical impact, and thus, we believe it should not be used in treatment planning. Level IV, case series.

The use of immunosuppressive agents in the management of recalcitrant lower limb ulcers.

PubMed

Millen, A; Coulston, J; Brennan, J; Kennedy, T

2014-08-01

Lower limb ulcers that are resistant to standard forms of treatment place a significant burden on both patients and health services. There is no widely agreed definition of a recalcitrant ulcer but failure to heal following 6-12 months of focused treatment would identify a small group of patients with highly resistant ulceration. We describe a series of patients with recalcitrant ulceration for which immunosuppressive agents have been used. This is a case series of 13 patients who underwent immunomodulation therapy for lower limb ulcers at a tertiary referral university hospital. Regimens of immunomodulation used mainly ciclosporin and/or cyclophosphamide, with concurrent antibiotic therapy. Case notes and computer systems were analysed by two reviewers. A patient was deemed to have a success if their ulcer fully healed while on immunomodulation therapy. Over a period of eight years, from 2004-2012, 13 patients underwent immunomodulation therapy. Among these patients there were 18 ulcerated limbs. Ulcer healing occurred in 10 limbs out of 18 (55.6%) and full healing occurred in six patients (46.2%). Ulcers were present for a median of five years (range 2-40 years), with a median diameter of 7.5 cm (range 4-18 cm) before treatment. Treatment of truly recalcitrant ulceration can be very frustrating for both the patient and physician, with poor success from more standard forms of treatment. We report experience with immunomodulation therapy that suggests there may be benefit from using this treatment in a subset of patients with this debilitating disease.

Update on oak seed quality research: Hardwood recalcitrant seeds

Treesearch

Kristina F. Connor

2004-01-01

In 2 experiments, acorns of cherrybark oak (Quercus pagoda Raf.) and water oak (Q. nigra L.) were stored at 2 temperatures and 2 moisture contents for 3 years, and acorns of white oak (Q. alba L.) and cherrybark oak were desiccated over a span of up to 11 days and examined for physiological and biochemical...

Insights into cell wall structure of Sida hermaphrodita and its influence on recalcitrance.

PubMed

Damm, Tatjana; Pattathil, Sivakumar; Günl, Markus; Jablonowski, Nicolai David; O'Neill, Malcolm; Grün, Katharina Susanne; Grande, Philipp Michael; Leitner, Walter; Schurr, Ulrich; Usadel, Björn; Klose, Holger

2017-07-15

The perennial plant Sida hermaphrodita (Sida) is attracting attention as potential energy crop. Here, the first detailed view on non-cellulosic Sida cell wall polysaccharide composition, structure and architecture is given. Cell walls were prepared from Sida stems and sequentially extracted with aqueous buffers and alkali. The structures of the quantitatively predominant polysaccharides present in each fraction were determined by biochemical characterization, glycome profiling and mass spectrometry. The amounts of glucose released by Accellerase-1500 ® treatment of the cell wall and the cell wall residue remaining after each extraction were used to assess the roles of pectin and hemicellulose in the recalcitrance of Sida biomass. 4-O-Methyl glucuronoxylan with a low proportion of side substitutions was identified as the major non-cellulosic glycan component of Sida stem cell walls. Pectic polysaccharides and xylans were found to be associated with lignin, suggesting that these polysaccharides have roles in Sida cell wall recalcitrance to enzymatic hydrolysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Edge effects of forest gap in Pinus massoniana plantations on the decomposition of leaf litter recalcitrant components of Cinnamomum camphora and Toona ciliata.

PubMed

Zhang, Yan; Zhang, Dan Ju; Li, Xun; Liu, Hua; Zhang, Ming Jin; Yang, Wan Qin; Zhang, Jian

2016-04-22

The objective of the study was to evaluate the dynamics of recalcitrant components during foliar litter decomposition under edge effects of forest gap in Pinus massoniana plantations in the low hilly land, Sichuan basin. A field litterbag experiment was conducted in seven forest gaps with different sizes (100, 225, 400, 625, 900, 1225, 1600 m 2 ) which were generated by thinning P. massoniana plantations. The degradation rate of four recalcitrant components, i.e., condensed tannins, total phenol, lignin and cellulose in foliar litter of two native species (Cinnamomum camphora and Toona ciliata) at the gap edge and under the closed canopy were measured. The results showed that the degradation rate of recalcitrant components in T. ciliata litter except for cellulose at the gap edge were significantly higher than that under the closed canopy. For C. camphora litter, only the degradation of lignin at the gap edge was higher than that under the closed canopy. After one-year decomposition, four recalcitrant components in two types of foliar litter exhibited an increment of degradation rate, and the degradation rate of condensed tannin was the fastest, followed by total phenol and cellulose, but the lignin degradation rate was the slowest. With the increase of gap size, except for cellulose, the degradation rate ofthe other three recalcitrant components of the T. ciliata at the edge of medium sized gaps (400 and 625 m 2 ) were significantly higher than at the edge of other gaps. However, lignin in the C. camphora litter at the 625 m 2 gap edge showed the greatest degradation rate. Both temperature and litter initial content were significantly correlated with litter recalcitrant component degradation. Our results suggested that medium sized gaps (400-625 m 2 ) had a more significant edge effect on the degradation of litter recalcitrant components in the two native species in P. massoniana plantations, however, the effect also depended on species.

Analysis of a Modern Hybrid and an Ancient Sugarcane Implicates a Complex Interplay of Factors in Affecting Recalcitrance to Cellulosic Ethanol Production

PubMed Central

Ricci-Silva, Maria Esther; Rhys Williams, Thomas Christopher; Alves Peçanha, Diego; Contin Ventrella, Marília; Rencoret, Jorge; Ralph, John; Pereira Barbosa, Márcio Henrique; Loureiro, Marcelo

2015-01-01

Abundant evidence exists to support a role for lignin as an important element in biomass recalcitrance. However, several independent studies have also shown that factors apart from lignin are also relevant and overall, the relative importance of different recalcitrance traits remains in dispute. In this study we used two genetically distant sugarcane genotypes, and performed a correlational study with the variation in anatomical parameters, cell wall composition, and recalcitrance factors between these genotypes. In addition we also tracked alterations in these characteristics in internodes at different stages of development. Significant differences in the development of the culm between the genotypes were associated with clear differential distributions of lignin content and composition that were not correlated with saccharification and fermentation yield. Given the strong influence of the environment on lignin content and composition, we hypothesized that sampling within a single plant could allow us to more easily interpret recalcitrance and changes in lignin biosynthesis than analysing variations between different genotypes with extensive changes in plant morphology and culm anatomy. The syringyl/guaiacyl (S/G) ratio was higher in the oldest internode of the modern genotype, but S/G ratio was not correlated with enzymatic hydrolysis yield nor fermentation efficiency. Curiously we observed a strong positive correlation between ferulate ester level and cellulose conversion efficiency. Together, these data support the hypothesis that biomass enzymatic hydrolysis recalcitrance is governed by a quantitative heritage rather than a single trait. PMID:26252208

Transcriptome Analysis of Taxillusi chinensis (DC.) Danser Seeds in Response to Water Loss

PubMed Central

Wei, Shugen; Ma, Xiaojun; Pan, Limei; Miao, Jianhua; Fu, Jine; Bai, Longhua; Zhang, Zhonglian; Guan, Yanhong; Mo, Changming; Huang, Hao; Chen, Maoshan

2017-01-01

Background Taxillus chinensis (DC.) Danser, the official species of parasitic loranthus that grows by parasitizing other plants, is used in various traditional Chinese medicine prescriptions. ABA-dependent and ABA-independent pathways are two major pathways in response to drought stress for plants and some genes have been reported to play a key role during the dehydration including dehydration-responsive protein RD22, late embryogenesis abundant (LEA) proteins, and various transcription factors (TFs) like MYB and WRKY. However, genes responding to dehydration are still unknown in loranthus. Methods and Results Initially, loranthus seeds were characterized as recalcitrant seeds. Then, biological replicates of fresh loranthus seeds (CK), and seeds after being dehydrated for 16 hours (Tac-16) and 36 hours (Tac-36) were sequenced by RNA-Seq, generating 386,542,846 high quality reads. A total of 164,546 transcripts corresponding to 114,971 genes were assembled by Trinity and annotated by mapping them to NCBI non-redundant (NR), UniProt, GO, KEGG pathway and COG databases. Transcriptome profiling identified 60,695, 56,027 and 66,389 transcripts (>1 FPKM) in CK, Tac-16 and Tac-36, respectively. Compared to CK, we obtained 2,102 up-regulated and 1,344 down-regulated transcripts in Tac-16 and 1,649 up-regulated and 2,135 down-regulated transcripts in Tac-36 by using edgeR. Among them some have been reported to function in dehydration process, such as RD22, heat shock proteins (HSP) and various TFs (MYB, WRKY and ethylene-responsive transcription factors). Interestingly, transcripts encoding ribosomal proteins peaked in Tac-16. It is indicated that HSPs and ribosomal proteins may function in early response to drought stress. Raw sequencing data can be accessed in NCBI SRA platform under the accession number SRA309567. Conclusions This is the first time to profile transcriptome globally in loranthus seeds. Our findings provide insights into the gene regulations of loranthus

Why is intracellular ice lethal? A microscopical study showing evidence of programmed cell death in cryo-exposed embryonic axes of recalcitrant seeds of Acer saccharinum.

PubMed

Wesley-Smith, James; Walters, Christina; Pammenter, N W; Berjak, Patricia

2015-05-01

Conservation of the genetic diversity afforded by recalcitrant seeds is achieved by cryopreservation, in which excised embryonic axes (or, where possible, embryos) are treated and stored at temperatures lower than -180 °C using liquid nitrogen. It has previously been shown that intracellular ice forms in rapidly cooled embryonic axes of Acer saccharinum (silver maple) but this is not necessarily lethal when ice crystals are small. This study seeks to understand the nature and extent of damage from intracellular ice, and the course of recovery and regrowth in surviving tissues. Embryonic axes of A. saccharinum, not subjected to dehydration or cryoprotection treatments (water content was 1·9 g H2O g(-1) dry mass), were cooled to liquid nitrogen temperatures using two methods: plunging into nitrogen slush to achieve a cooling rate of 97 °C s(-1) or programmed cooling at 3·3 °C s(-1). Samples were thawed rapidly (177 °C s(-1)) and cell structure was examined microscopically immediately, and at intervals up to 72 h in vitro. Survival was assessed after 4 weeks in vitro. Axes were processed conventionally for optical microscopy and ultrastructural examination. Immediately following thaw after cryogenic exposure, cells from axes did not show signs of damage at an ultrastructural level. Signs that cells had been damaged were apparent after several hours of in vitro culture and appeared as autophagic decomposition. In surviving tissues, dead cells were sloughed off and pockets of living cells were the origin of regrowth. In roots, regrowth occurred from the ground meristem and procambium, not the distal meristem, which became lethally damaged. Regrowth of shoots occurred from isolated pockets of surviving cells of peripheral and pith meristems. The size of these pockets may determine the possibility for, the extent of and the vigour of regrowth. Autophagic degradation and ultimately autolysis of cells following cryo-exposure and formation of small

Recalcitrant deep and shallow nodes in Aristolochia (Aristolochiaceae) illuminated using anchored hybrid enrichment.

PubMed

Wanke, Stefan; Granados Mendoza, Carolina; Müller, Sebastian; Paizanni Guillén, Anna; Neinhuis, Christoph; Lemmon, Alan R; Lemmon, Emily Moriarty; Samain, Marie-Stéphanie

2017-12-01

Recalcitrant relationships are characterized by very short internodes that can be found among shallow and deep phylogenetic scales all over the tree of life. Adding large amounts of presumably informative sequences, while decreasing systematic error, has been suggested as a possible approach to increase phylogenetic resolution. The development of enrichment strategies, coupled with next generation sequencing, resulted in a cost-effective way to facilitate the reconstruction of recalcitrant relationships. By applying the anchored hybrid enrichment (AHE) genome partitioning strategy to Aristolochia using an universal angiosperm probe set, we obtained 231-233 out of 517 single or low copy nuclear loci originally contained in the enrichment kit, resulting in a total alignment length of 154,756bp to 160,150bp. Since Aristolochia (Piperales; magnoliids) is distantly related to any angiosperm species whose genome has been used for the plant AHE probe design (Amborella trichopoda being the closest), it serves as a proof of universality for this probe set. Aristolochia comprises approximately 500 species grouped in several clades (OTUs), whose relationships to each other are partially unknown. Previous phylogenetic studies have shown that these lineages branched deep in time and in quick succession, seen as short-deep internodes. Short-shallow internodes are also characteristic of some Aristolochia lineages such as Aristolochia subsection Pentandrae, a clade of presumably recent diversification. This subsection is here included to test the performance of AHE at species level. Filtering and subsampling loci using the phylogenetic informativeness method resolves several recalcitrant phylogenetic relationships within Aristolochia. By assuming different ploidy levels during bioinformatics processing of raw data, first hints are obtained that polyploidization contributed to the evolution of Aristolochia. Phylogenetic results are discussed in the light of current systematics and

The response difference of mitochondria in recalcitrant Antiaris toxicaria axes and orthodox Zea mays embryos to dehydration injury.

PubMed

Song, Song-Quan; Tian, Mei-Hua; Kan, Jing; Cheng, Hong-Yan

2009-07-01

Long-term preservation of recalcitrant seeds is very difficult because the physiological basis on their desiccation sensitivity is poorly understood. Survival of Antiaris toxicaria axes rapidly decreased and that of immature maize embryos very slowly decreased with dehydration. To understand their different responses to dehydration, we examined the changes in mitochondria activity during dehydration. Although activities of cytochrome (Cyt) c oxidase and malate dehydrogenase of the A. toxicaria axis and maize embryo mitochondria decreased with dehydration, the parameters of maize embryo mitochondria were much higher than those of A. toxicaria, showing that the damage was more severe for the A. toxicaria axis mitochondria than for those of maize embryo. The state I and III respiration of the A. toxicaria axis mitochondria were higher than those of maize embryo, the former rapidly decreased, and the latter slowly decreased with dehydration. The proportion of Cyt c pathway to state III respiration for the A. toxicaria axis mitochondria was low and rapidly decreased with dehydration, and the proportion of alternative oxidase pathway was high and slightly increased with dehydration. In contrast, the proportion of Cyt c pathway for maize embryo mitochondria was high, and that of alternative oxidase pathway was low. Both pathways decreased slowly with dehydration.

Comparative transcriptional analysis provides new insights into the molecular basis of adventitious rooting recalcitrance in Eucalyptus.

PubMed

de Almeida, Márcia Rodrigues; de Bastiani, Daniela; Gaeta, Marcos Letaif; de Araújo Mariath, Jorge Ernesto; de Costa, Fernanda; Retallick, Jeffrey; Nolan, Lana; Tai, Helen H; Strömvik, Martina V; Fett-Neto, Arthur Germano

2015-10-01

Adventitious rooting (AR) is essential in clonal propagation. Eucalyptus globulus is relevant for the cellulose industry due to its low lignin content. However, several useful clones are recalcitrant to AR, often requiring exogenous auxin, adding cost to clonal garden operations. In contrast, E. grandis is an easy-to-root species widely used in clonal forestry. Aiming at contributing to the elucidation of recalcitrance causes in E. globulus, we conducted a comparative analysis with these two species differing in rooting competence, combining gene expression and anatomical techniques. Recalcitrance in E. globulus is reversed by exposure to exogenous indole-3-acetic acid (IAA), which promotes important gene expression modifications in both species. The endogenous content of IAA was significantly higher in E. grandis than in E. globulus. The cambium zone was identified as an active area during AR, concentrating the first cell divisions. Immunolocalization assay showed auxin accumulation in cambium cells, further indicating the importance of this region for rooting. We then performed a cambium zone-specific gene expression analysis during AR using laser microdissection. The results indicated that the auxin-related genes TOPLESS and IAA12/BODENLOS and the cytokinin-related gene ARR1may act as negative regulators of AR, possibly contributing to the hard-to-root phenotype of E. globulus. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Rate of Dehydration and Cumulative Desiccation Stress Interacted to Modulate Desiccation Tolerance of Recalcitrant Cocoa and Ginkgo Embryonic Tissues1

PubMed Central

Liang, Yongheng; Sun, Wendell Q.

2002-01-01

Rate of dehydration greatly affects desiccation tolerance of recalcitrant seeds. This effect is presumably related to two different stress vectors: direct mechanical or physical stress because of the loss of water and physicochemical damage of tissues as a result of metabolic alterations during drying. The present study proposed a new theoretic approach to represent these two types of stresses and investigated how seed tissues responded differently to two stress vectors, using the models of isolated cocoa (Theobroma cacao) and ginkgo (Ginkgo biloba) embryonic tissues dehydrated under various drying conditions. This approach used the differential change in axis water potential (ΔΨ/Δt) to quantify rate of dehydration and the intensity of direct physical stress experienced by embryonic tissues during desiccation. Physicochemical effect of drying was expressed by cumulative desiccation stress [∫\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\pagestyle{empty} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{_{o}^{t}}}\\end{equation*}\\end{document}f(ψ,t)], a function of both the rate and time of dehydration. Rapid dehydration increased the sensitivity of embryonic tissues to desiccation as indicated by high critical water contents, below which desiccation damage occurred. Cumulative desiccation stress increased sharply under slow drying conditions, which was also detrimental to embryonic tissues. This quantitative analysis of the stress-time-response relationship helps to understand the physiological basis for the existence of an optimal dehydration rate, with which maximum desiccation tolerance could be achieved. The established numerical analysis model will prove valuable for the design of experiments that aim to elucidate biochemical and physiological mechanisms of desiccation tolerance. PMID:11950981

β-Glucans and Resistant Starch Alter the Fermentation of Recalcitrant Fibers in Growing Pigs.

PubMed

de Vries, Sonja; Gerrits, Walter J J; Kabel, Mirjam A; Vasanthan, Thava; Zijlstra, Ruurd T

2016-01-01

Interactions among dietary ingredients are often assumed non-existent when evaluating the nutritive value and health effects of dietary fiber. Specific fibers can distinctly affect digestive processes; therefore, digestibility and fermentability of the complete diet may depend on fiber types present. This study aimed to evaluate the effects of readily fermentable fibers (β-glucans and resistant starch) on the degradation of feed ingredients containing more persistent, recalcitrant, fibers. Six semi-synthetic diets with recalcitrant fibers from rapeseed meal (pectic polysaccharides, xyloglucans, and cellulose) or corn distillers dried grain with solubles (DDGS; (glucurono)arabinoxylans and cellulose) with or without inclusion of β-glucans (6%) or retrograded tapioca (40%) substituted for corn starch were formulated. Six ileal-cannulated pigs (BW 28±1.4 kg) were assigned to the diets according to a 6×6 Latin square. β-glucan-extract increased apparent total tract digestibility (ATTD) of non-glucosyl polysaccharides (accounting for ~40% of the fiber-fraction) from rapeseed meal (6%-units, P<0.001), but did not affect non-glucosyl polysaccharides from DDGS. Retrograded tapioca reduced ATTD of non-glucosyl polysaccharides from rapeseed meal and DDGS (>10%-units, P<0.001), indicating that the large amount of resistant starch entering the hindgut was preferentially degraded over recalcitrant fibers from rapeseed meal and DDGS, possibly related to reduced hindgut-retention time following the increased intestinal bulk. Fermentation of fiber sources was not only dependent on fiber characteristics, but also on the presence of other fibers in the diet. Hence, interactions in the gastrointestinal tract among fibrous feed ingredients should be considered when evaluating their nutritive value.

β-Glucans and Resistant Starch Alter the Fermentation of Recalcitrant Fibers in Growing Pigs

PubMed Central

Gerrits, Walter J. J.; Kabel, Mirjam A.; Vasanthan, Thava; Zijlstra, Ruurd T.

2016-01-01

Interactions among dietary ingredients are often assumed non-existent when evaluating the nutritive value and health effects of dietary fiber. Specific fibers can distinctly affect digestive processes; therefore, digestibility and fermentability of the complete diet may depend on fiber types present. This study aimed to evaluate the effects of readily fermentable fibers (β-glucans and resistant starch) on the degradation of feed ingredients containing more persistent, recalcitrant, fibers. Six semi-synthetic diets with recalcitrant fibers from rapeseed meal (pectic polysaccharides, xyloglucans, and cellulose) or corn distillers dried grain with solubles (DDGS; (glucurono)arabinoxylans and cellulose) with or without inclusion of β-glucans (6%) or retrograded tapioca (40%) substituted for corn starch were formulated. Six ileal-cannulated pigs (BW 28±1.4 kg) were assigned to the diets according to a 6×6 Latin square. β-glucan-extract increased apparent total tract digestibility (ATTD) of non-glucosyl polysaccharides (accounting for ~40% of the fiber-fraction) from rapeseed meal (6%-units, P<0.001), but did not affect non-glucosyl polysaccharides from DDGS. Retrograded tapioca reduced ATTD of non-glucosyl polysaccharides from rapeseed meal and DDGS (>10%-units, P<0.001), indicating that the large amount of resistant starch entering the hindgut was preferentially degraded over recalcitrant fibers from rapeseed meal and DDGS, possibly related to reduced hindgut-retention time following the increased intestinal bulk. Fermentation of fiber sources was not only dependent on fiber characteristics, but also on the presence of other fibers in the diet. Hence, interactions in the gastrointestinal tract among fibrous feed ingredients should be considered when evaluating their nutritive value. PMID:27911928

Genome Assembly of the Fungus Cochliobolus miyabeanus, and Transcriptome Analysis during Early Stages of Infection on American Wildrice (Zizania palustris L.)

PubMed Central

Castell-Miller, Claudia V.; Gutierrez-Gonzalez, Juan J.; Tu, Zheng Jin; Bushley, Kathryn E.; Hainaut, Matthieu; Henrissat, Bernard; Samac, Deborah A.

2016-01-01

The fungus Cochliobolus miyabeanus causes severe leaf spot disease on rice (Oryza sativa) and two North American specialty crops, American wildrice (Zizania palustris) and switchgrass (Panicum virgatum). Despite the importance of C. miyabeanus as a disease-causing agent in wildrice, little is known about either the mechanisms of pathogenicity or host defense responses. To start bridging these gaps, the genome of C. miyabeanus strain TG12bL2 was shotgun sequenced using Illumina technology. The genome assembly consists of 31.79 Mbp in 2,378 scaffolds with an N50 = 74,921. It contains 11,000 predicted genes of which 94.5% were annotated. Approximately 10% of total gene number is expected to be secreted. The C. miyabeanus genome is rich in carbohydrate active enzymes, and harbors 187 small secreted peptides (SSPs) and some fungal effector homologs. Detoxification systems were represented by a variety of enzymes that could offer protection against plant defense compounds. The non-ribosomal peptide synthetases and polyketide synthases (PKS) present were common to other Cochliobolus species. Additionally, the fungal transcriptome was analyzed at 48 hours after inoculation in planta. A total of 10,674 genes were found to be expressed, some of which are known to be involved in pathogenicity or response to host defenses including hydrophobins, cutinase, cell wall degrading enzymes, enzymes related to reactive oxygen species scavenging, PKS, detoxification systems, SSPs, and a known fungal effector. This work will facilitate future research on C. miyabeanus pathogen-associated molecular patterns and effectors, and in the identification of their corresponding wildrice defense mechanisms. PMID:27253872

Combined 595-nm and 1,064-nm laser irradiation of recalcitrant and hypertrophic port-wine stains in children and adults.

PubMed

Alster, Tina S; Tanzi, Elizabeth L

2009-06-01

Although pulsed dye laser (PDL) treatment of port-wine stain (PWS) has long been proven safe and effective, incomplete clearance of these vascular malformations can be problematic. In addition, advanced PWS with deeper coloration and tissue hypertrophy can be particularly difficult to treat because of the superficial dermal penetration of 585- to 595-nm light. The purpose of this study was to evaluate the safety and efficacy of a novel device that delivers sequential pulses of 595- and 1,064-nm wavelengths in the treatment of recalcitrant and hypertrophic PWS. Twenty-five children and adults (skin phototypes I-III) with recalcitrant or hypertrophic PWS showing incomplete clearance after 10 prior PDL treatments were included in the study. Successive treatments using a 595-nm PDL and a 1,064-nm neodymium-doped yttrium-aluminum-garnet (Nd:YAG) laser were delivered at 6- to 8-week intervals. Two masked assessors determined clinical improvement of treatment areas using independent evaluation of comparative photographs at baseline and 3 months after treatment using a standard quartile grading scale. The use of dual 595-/1,064-nm wavelengths provided continued improvement of PWS that were previously recalcitrant to ongoing PDL therapy. Side effects were limited to transient erythema, edema, and mild purpura. Rare vesicle formation was observed, with no subsequent scarring or undesirable pigmentary changes. The novel dual 595-nm PDL and 1,064-nm Nd:YAG laser is an effective treatment for PWS that are recalcitrant to PDL therapy alone.

Lignin Exhibits Recalcitrance-Associated Features Following the Consolidated Bioprocessing of Populus trichocarpa Natural Variants

DOE PAGES

Akinosho, Hannah; Yee, Kelsey; Rodriguez, Miguel; ...

2017-11-21

Because cellulosic ethanol production remains cost-prohibitive„ advances in consolidated bioprocessing (CBP) have been directed towards lifting this restriction. CBP reduces the need for added enzymes and can potentially slash ethanol production costs through process integration. Clostridium thermocellum, a CBP microorganism, organizes its enzymes in a multi-enzyme complex - a stark contrast to fungal enzymes. Nonetheless, recalcitrance may limit the extent of biomass deconstruction. Here in this study, six Populus were treated with C. thermocellum (ATCC 27405) and characterized to determine structural changes that resulted from CBP. The 2D HSQC NMR spectra of lignin-enriched residues revealed that higher S/G ratio (2.6)more » and fewer carbon-carbon interunit linkages (generally 2–5%) were present in the top performing poplar. Furthermore, cellulose degree of polymerization data suggests that C. thermocellum likely circumvents long chain cellulose, while cellulose crystallinity and hemicellulose molecular weight data do not provide a direct indication of features connected to recalcitrance. Hence, C. thermocellum is similarly impacted by the proposed lignin properties that negatively impact biomass deconstruction using fungal enzymes.« less

Microbial enzymes for the recycling of recalcitrant petroleum-based plastics: how far are we?

PubMed

Wei, Ren; Zimmermann, Wolfgang

2017-11-01

Petroleum-based plastics have replaced many natural materials in their former applications. With their excellent properties, they have found widespread uses in almost every area of human life. However, the high recalcitrance of many synthetic plastics results in their long persistence in the environment, and the growing amount of plastic waste ending up in landfills and in the oceans has become a global concern. In recent years, a number of microbial enzymes capable of modifying or degrading recalcitrant synthetic polymers have been identified. They are emerging as candidates for the development of biocatalytic plastic recycling processes, by which valuable raw materials can be recovered in an environmentally sustainable way. This review is focused on microbial biocatalysts involved in the degradation of the synthetic plastics polyethylene, polystyrene, polyurethane and polyethylene terephthalate (PET). Recent progress in the application of polyester hydrolases for the recovery of PET building blocks and challenges for the application of these enzymes in alternative plastic waste recycling processes will be discussed. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

The effect of liquid hot water pretreatment on the chemical-structural alteration and the reduced recalcitrance in poplar.

PubMed

Li, Mi; Cao, Shilin; Meng, Xianzhi; Studer, Michael; Wyman, Charles E; Ragauskas, Arthur J; Pu, Yunqiao

2017-01-01

Hydrothermal pretreatment using liquid hot water (LHW) is capable of substantially reducing the cell wall recalcitrance of lignocellulosic biomass. It enhances the saccharification of polysaccharides, particularly cellulose, into glucose with relatively low capital required. Due to the close association with biomass recalcitrance, the structural change of the components of lignocellulosic materials during the pretreatment is crucial to understand pretreatment chemistry and advance the bio-economy. Although the LHW pretreatment has been extensively applied and studied, the molecular structural alteration during pretreatment and its significance to reduced recalcitrance have not been well understood. We investigated the effects of LHW pretreatment with different severity factors (log R 0 ) on the structural changes of fast-grown poplar ( Populus trichocarpa ). With the severity factor ranging from 3.6 to 4.2, LHW pretreatment resulted in a substantial xylan solubilization by 50-77% ( w/w , dry matter). The molecular weights of the remained hemicellulose in pretreated solids also have been significantly reduced by 63-75% corresponding to LHW severity factor from 3.6 to 4.2. In addition, LHW had a considerable impact on the cellulose structure. The cellulose crystallinity increased 6-9%, whereas its degree of polymerization decreased 35-65% after pretreatment. We found that the pretreatment severity had an empirical linear correlation with the xylan solubilization ( R 2  = 0.98, r  = + 0.99), hemicellulose molecular weight reduction ( R 2  = 0.97, r  = - 0.96 and R 2  = 0.93, r  = - 0.98 for number-average and weight-average degree of polymerization, respectively), and cellulose crystallinity index increase ( R 2  = 0.98, r  = + 0.99). The LHW pretreatment also resulted in small changes in lignin structure such as decrease of β- O -4' ether linkages and removal of cinnamyl alcohol end group and acetyl group, while the S/G ratio of lignin in LHW

Lower trapezius flap for recalcitrant wounds of the posterior skull and spine

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

Seyfer, A.E.

1988-05-01

The lower trapezius muscle and musculocutaneous flap has been useful in providing a reliable, expeditious closure for compromised defects of the upper spine and dorsal calvarium. It has been successfully employed in 6 patients as a one-stage procedure, all of whom had recalcitrant, postoperative wounds that failed to heal. It provides serviceable tissue that is able to withstand additional radiotherapy and also offers useful palliation without apparent disability. Pertinent anatomical and clinical considerations are discussed.

Genome assembly of the fungus Cochliobolus miyabeanus, and transcriptome analysis during early stages of infection on American wildrice ( Zizania palustris L.)

DOE PAGES

Castell-Miller, Claudia V.; Gutierrez-Gonzalez, Juan J.; Tu, Zheng Jin; ...

2016-06-02

Here, the fungus Cochliobolus miyabeanus causes severe leaf spot disease on rice ( Oryza sativa) and two North American specialty crops, American wildrice ( Zizania palustris) and switchgrass ( Panicum virgatu). Despite the importance of C. miyabeanus as a disease-causing agent in wildrice, little is known about either the mechanisms of pathogenicity or host defense responses. To start bridging these gaps, the genome of C. miyabeanus strain TG12bL2 was shotgun sequenced using Illumina technology. The genome assembly consists of 31.79 Mbp in 2,378 scaffolds with an N 50 = 74,921. It contains 11,000 predicted genes of which 94.5% were annotated.more » Approximately 10% of total gene number is expected to be secreted. The C. miyabeanus genome is rich in carbohydrate active enzymes, and harbors 187 small secreted peptides (SSPs) and some fungal effector homologs. Detoxification systems were represented by a variety of enzymes that could offer protection against plant defense compounds. The non-ribosomal peptide synthetases and polyketide synthases (PKS) present were common to other Cochliobolus species. Additionally, the fungal transcriptome was analyzed at 48 hours after inoculation in planta. A total of 10,674 genes were found to be expressed, some of which are known to be involved in pathogenicity or response to host defenses including hydrophobins, cutinase, cell wall degrading enzymes, enzymes related to reactive oxygen species scavenging, PKS, detoxification systems, SSPs, and a known fungal effector. This work will facilitate future research on C. miyabeanus pathogen-associated molecular patterns and effectors, and in the identification of their corresponding wildrice defense mechanisms.« less

Genome assembly of the fungus Cochliobolus miyabeanus, and transcriptome analysis during early stages of infection on American wildrice ( Zizania palustris L.)

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

Castell-Miller, Claudia V.; Gutierrez-Gonzalez, Juan J.; Tu, Zheng Jin

Here, the fungus Cochliobolus miyabeanus causes severe leaf spot disease on rice ( Oryza sativa) and two North American specialty crops, American wildrice ( Zizania palustris) and switchgrass ( Panicum virgatu). Despite the importance of C. miyabeanus as a disease-causing agent in wildrice, little is known about either the mechanisms of pathogenicity or host defense responses. To start bridging these gaps, the genome of C. miyabeanus strain TG12bL2 was shotgun sequenced using Illumina technology. The genome assembly consists of 31.79 Mbp in 2,378 scaffolds with an N 50 = 74,921. It contains 11,000 predicted genes of which 94.5% were annotated.more » Approximately 10% of total gene number is expected to be secreted. The C. miyabeanus genome is rich in carbohydrate active enzymes, and harbors 187 small secreted peptides (SSPs) and some fungal effector homologs. Detoxification systems were represented by a variety of enzymes that could offer protection against plant defense compounds. The non-ribosomal peptide synthetases and polyketide synthases (PKS) present were common to other Cochliobolus species. Additionally, the fungal transcriptome was analyzed at 48 hours after inoculation in planta. A total of 10,674 genes were found to be expressed, some of which are known to be involved in pathogenicity or response to host defenses including hydrophobins, cutinase, cell wall degrading enzymes, enzymes related to reactive oxygen species scavenging, PKS, detoxification systems, SSPs, and a known fungal effector. This work will facilitate future research on C. miyabeanus pathogen-associated molecular patterns and effectors, and in the identification of their corresponding wildrice defense mechanisms.« less

On polydispersity of plant biomass recalcitrance and its effects on pretreatment optimization for sugar production

Treesearch

J.Y. Zhu; Steve P. Verrill; Hao Liu; Victoria L. Herian; Xuejun Pan; Donald L. Rockwood

2011-01-01

This paper discusses a property associated with plant biomass recalcitrance to enzyme and microbial deconstructions in sugar production from cellulose and hemicelluloses. The hemicelluloses are more readily hydrolyzed to sugars than is cellulose. As a result, optimization to maximize individual glucose and hemicellulose sugar recovery is not possible. This property is...

Biomass-water interactions correlate to recalcitrance and are intensified by pretreatment: An investigation of water constraint and retention in pretreated spruce using low field NMR and water retention value techniques.

PubMed

Weiss, Noah D; Thygesen, Lisbeth Garbrecht; Felby, Claus; Roslander, Christian; Gourlay, Keith

2017-01-01

The underlying mechanisms of the recalcitrance of biomass to enzymatic deconstruction are still not fully understood, and this hampers the development of biomass based fuels and chemicals. With water being necessary for most biological processes, it is suggested that interactions between water and biomass may be key to understanding and controlling biomass recalcitrance. This study investigates the correlation between biomass recalcitrance and the constraint and retention of water by the biomass, using SO 2 pretreated spruce, a common feedstock for lignocellulosic biofuel production, as a substrate to evaluate this relationship. The water retention value (WRV) of the pretreated materials was measured, and water constraint was assessed using time domain Low Field Nuclear Magnetic Resonance (LFNMR) relaxometry. WRV increased with pretreatment severity, correlating to reduced recalcitrance, as measured by hydrolysis of cellulose using commercial enzyme preparations. Water constraint increased with pretreatment severity, suggesting that a higher level of biomass-water interaction is indicative of reduced recalcitrance in pretreated materials. Both WRV and water constraint increased significantly with reductions in particle size when pretreated materials were further milled, suggesting that particle size plays an important role in biomass water interactions. It is suggested that WRV may be a simple and effective method for measuring and comparing biomass recalcitrance. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:146-153, 2017. © 2016 American Institute of Chemical Engineers.

Characterization of ischemic index using ultra-widefield fluorescein angiography in patients with focal and diffuse recalcitrant diabetic macular edema.

PubMed

Patel, Ravi D; Messner, Leonard V; Teitelbaum, Bruce; Michel, Kimberly A; Hariprasad, Seenu M

2013-06-01

To explore the association of angiographic nonperfusion in focal and diffuse recalcitrant diabetic macular edema (DME) in diabetic retinopathy (DR). A retrospective, observational case series of patients with the diagnosis of recalcitrant DME for at least 2 years placed into 1 of 4 cohorts based on the degree of DR. A total of 148 eyes of 76 patients met the inclusion criteria at 1 academic institution. Ultra-widefield fluorescein angiography (FA) images and spectral-domain optical coherence tomography (SD OCT) images were obtained on all patients. Ultra-widefield FA images were graded for quantity of nonperfusion, which was used to calculate ischemic index. Main outcome measures were mean ischemic index, mean change in central macular thickness (CMT), and mean number of macular photocoagulation treatments over the 2-year study period. The mean ischemic index was 47% (SD 25%; range 0%-99%). The mean ischemic index of eyes within Cohorts 1, 2, 3, and 4 was 0%, 34% (range 16%-51%), 53% (range 32%-89%), and 65% (range 47%-99%), respectively. The mean percentage decrease in CMT in Cohorts 1, 2, 3, and 4 were 25.2%, 19.1%, 11.6%, and 7.2%, respectively. The mean number of macular photocoagulation treatments in Cohorts 1, 2, 3, and 4 was 2.3, 4.8, 5.3, and 5.7, respectively. Eyes with larger areas of retinal nonperfusion and greater severity of DR were found to have the most recalcitrant DME, as evidenced by a greater number of macular photocoagulation treatments and less reduction in SD OCT CMT compared with eyes without retinal nonperfusion. Areas of untreated retinal nonperfusion may generate biochemical mediators that promote ischemia and recalcitrant DME. Copyright © 2013 Elsevier Inc. All rights reserved.

Investigation of Plant Cell Wall Properties: A Study of Contributions from the Nanoscale to the Macroscale Impacting Cell Wall Recalcitrance

NASA Astrophysics Data System (ADS)

Crowe, Jacob Dillon

Biochemical conversion of lignocellulosic biomass to fuel ethanol is one of a few challenging, yet opportune technologies that can reduce the consumption of petroleum-derived transportation fuels, while providing parallel reductions in greenhouse gas emissions. Biomass recalcitrance, or resistance to deconstruction, is a major technical challenge that limits effective conversion of biomass to fermentable sugars, often requiring a costly thermochemical pretreatment step to improve biomass deconstruction. Biomass recalcitrance is imparted largely by the secondary cell wall, a complex polymeric matrix of cell wall polysaccharides and aromatic heteropolymers, that provides structural stability to cells and enables plant upright growth. Polymers within the cell wall can vary both compositionally and structurally depending upon plant species and anatomical fraction, and have varied responses to thermochemical pretreatments. Cell wall properties impacting recalcitrance are still not well understood, and as a result, the goal of this dissertation is to investigate structural features of the cell wall contributing to recalcitrance (1) in diverse anatomical fractions of a single species, (2) in response to diverse pretreatments, and (3) resulting from genetic modification. In the first study, feedstock cell wall heterogeneity was investigated in anatomical (stem, leaf sheaths, and leaf blades) and internode fractions of switchgrass at varying tissue maturities. Lignin content was observed as the key contributor to recalcitrance in maturing stem tissues only, with non-cellulosic substituted glucuronoarabinoxylans and pectic polysaccharides contributing to cell wall recalcitrance in leaf sheath and leaf blades. Hydroxycinnamate (i.e., saponifiable p-coumarate and ferulate) content along with xylan and pectin extractability decreased with tissue maturity, suggesting lignification is only one component imparting maturity specific cell wall recalcitrance. In the second study

Induction of tolerance to desiccation and cryopreservation in silver maple (Acer saccharinum) embryonic axes.

PubMed

Beardmore, T; Whittle, C-A

2005-08-01

Twenty percent of of the world's flowering plants produce recalcitrant seeds (i.e., seeds that cannot withstand drying or freezing). We investigated whether the embryonic axis from the normally recalcitrant seeds of silver maple (Acer saccharinum L.) can be made tolerant to desiccation (10% water content) and low temperature (-196 degrees C, cryopreservation) by pretreatment with ABA or the compound tetcyclacis, which enhances endogenous ABA concentrations. Pretreatment of axes with both ABA and tetcyclacis increased germination after desiccation and freezing to 55% from a control value of zero. Pretreatment of axes with ABA and tetcyclacis increased the ABA content of the axes, as measured by enzyme-linked immunoassay, and stimulated the synthesis of storage and dehydrin-like proteins, believed to have a role in the desiccation tolerance of orthodox seeds.

Recalcitrance and structural analysis by water-only flowthrough pretreatment of 13C enriched corn stover stem

DOE PAGES

Foston, Marcus; Trajano, Heather L.; Samuel, Reichel; ...

2015-08-28

This article presents high temperature water-only continuous flowthrough pretreatment coupled with nuclear magnetic resonance (NMR) as a promising analytical tool to examine the plant cell wall, to understand its recalcitrance (i.e., cell wall resistance to deconstruction), and to probe the chemistry occurring during batch pretreatment of biomass. 13C-enriched corn stover stems were pretreated at 170 °C for 60 minutes with a hot-water flow rate of 20 mL/min to control fractionation of the cell wall. This approach helped elucidate the nature of plant cell wall chemical recalcitrance and biomass pretreatment chemistry by tracking cell wall fragmentation as a function of time.more » Fractions of the reactor effluent were collected in a time-resolved fashion and characterized by various NMR techniques to determine the degree and sequence of fragments released, as well as, the chemical composition, molecular structure, and relative molecular weight of those released fragments.« less

Recalcitrance and structural analysis by water-only flowthrough pretreatment of 13C enriched corn stover stem

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

Foston, Marcus; Trajano, Heather L.; Samuel, Reichel

This article presents high temperature water-only continuous flowthrough pretreatment coupled with nuclear magnetic resonance (NMR) as a promising analytical tool to examine the plant cell wall, to understand its recalcitrance (i.e., cell wall resistance to deconstruction), and to probe the chemistry occurring during batch pretreatment of biomass. 13C-enriched corn stover stems were pretreated at 170 °C for 60 minutes with a hot-water flow rate of 20 mL/min to control fractionation of the cell wall. This approach helped elucidate the nature of plant cell wall chemical recalcitrance and biomass pretreatment chemistry by tracking cell wall fragmentation as a function of time.more » Fractions of the reactor effluent were collected in a time-resolved fashion and characterized by various NMR techniques to determine the degree and sequence of fragments released, as well as, the chemical composition, molecular structure, and relative molecular weight of those released fragments.« less

Platelet-Rich Plasma Injection With Percutaneous Needling for Recalcitrant Lateral Epicondylitis: Comparison of Tenotomy and Fenestration Techniques.

PubMed

Gaspar, Michael P; Motto, Michael A; Lewis, Sarah; Jacoby, Sidney M; Culp, Randall W; Lee Osterman, A; Kane, Patrick M

2017-12-01

Recalcitrant lateral epicondylitis (LE) is a common debilitating condition, with numerous treatment options of varying success. An injection of platelet-rich plasma (PRP) has been shown to improve LE, although it is unclear whether the method of needling used in conjunction with a PRP injection is of clinical importance. To determine whether percutaneous needle tenotomy is superior to percutaneous needle fenestration when each is combined with a PRP injection for the treatment of recalcitrant LE. Cohort study; Level of evidence, 3. A total of 93 patients with recalcitrant LE were treated with a PRP injection and percutaneous needle fenestration (n = 45) or percutaneous needle tenotomy (n = 48) over a 5-year study interval. Preoperative patient data, including visual analog scale for pain (VAS-P), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), and Patient-Rated Tennis Elbow Evaluation (PRTEE) scores and grip strength, were obtained from a chart review and compared with postoperative values obtained prospectively. Secondary outcomes included the incidence of complications, need for additional interventions, return to work, and patient satisfaction. At a mean follow-up of 40 months, significant improvements in VAS-P (mean, -6.1; 95% CI, -6.8 to -5.5; P < .0001), QuickDASH (mean, -46; 95% CI, -52 to -40; P < .0001), and PRTEE (mean, -57; 95% CI, -64 to -50; P < .0001) scores and grip strength (mean, +6.1 kg; 95% CI, 4.9 to 7.3; P < .0001) were observed across the entire study cohort, with no significant differences noted between the fenestration and tenotomy groups. Nine of 45 patients (22%) underwent additional procedures to treat recurrent symptoms in the fenestration group compared with 5 of 48 patients (10%) in the tenotomy group ( P = .05). No complications occurred in any patients, and no patients expressed dissatisfaction with their treatment course. A PRP injection with concomitant percutaneous needling is an effective treatment for recalcitrant

Topical Colloidal Silver for the Treatment of Recalcitrant Chronic Rhinosinusitis.

PubMed

Ooi, Mian L; Richter, Katharina; Bennett, Catherine; Macias-Valle, Luis; Vreugde, Sarah; Psaltis, Alkis J; Wormald, Peter-John

2018-01-01

Background: The management of recalcitrant chronic rhinosinusitis (CRS) is challenged by difficult-to-treat polymicrobial biofilms and multidrug resistant bacteria. This has led to the search for broad-spectrum non-antibiotic antimicrobial therapies. Colloidal silver (CS) has significant antibiofilm activity in vitro and in vivo against S. aureus, MRSA , and P. aeruginosa . However, due to the lack of scientific efficacy, it is only currently used as an alternative medicine. This is the first study looking at the safety and efficacy of CS in recalcitrant CRS. Methods: Patients were included when they had previously undergone endoscopic sinus surgery and presented with signs and symptoms of sinus infection with positive bacterial cultures. Twenty-two patients completed the study. Patients were allocated to 10-14 days of culture directed oral antibiotics with twice daily saline rinses ( n = 11) or 10 days of twice daily 0.015 mg/mL CS rinses ( n = 11). Safety observations included pre- and post-treatment serum silver levels, University of Pennsylvania Smell Identification Test (UPSIT) and adverse event (AE) reporting. Efficacy was assessed comparing microbiology results, Lund Kennedy Scores (LKS) and symptom scores using Visual Analog Scale (VAS) and Sino-Nasal Outcome Test (SNOT-22). Results: CS demonstrated good safety profile with no major adverse events, no changes in UPSIT and transient serum silver level changes in 4 patients. CS patients had 1/11 (9.09%) negative cultures, compared to 2/11 (18.18%) in the control group upon completion of the study. Whilst not statistically significant, both groups showed similar improvement in symptoms and endoscopic scores. Conclusion: This study concludes that twice daily CS (0.015 mg/mL) sinonasal rinses for 10 days is safe but not superior to culture-directed oral antibiotics. Further studies including more patients and looking at longer treatment or improving the tonicity of the solution for better tolerability should be

Clinical outcomes after arthroscopic release for recalcitrant frozen shoulder.

PubMed

Ebrahimzadeh, Mohammad H; Moradi, Ali; Pour, Mostafa Khalili; Moghadam, Mohammad Hallaj; Kachooei, Amir Reza

2014-09-01

To explain the role of arthroscopic release in intractable frozen shoulders. We used different questionnaires and measuring tools to understand whether arthroscopic release is the superior modality to treat patients with intractable frozen shoulders. Between 2007 and 2013, in a prospective study, we enrolled 80 patients (52 females and 28 males) with recalcitrant frozen shoulder, who underwent arthroscopic release at Ghaem Hospital, a tertiary referral center, in Mashhad, Iran. Before operation, all patients filled out the Disability of Arm, Shoulder and Hand (DASH), Constant, University of California Los Angeles (UCLA), ROWE and Visual Analogue Scale (VAS) for pain questionnaires. We measured the difference in range of motion between both the normal and the frozen shoulders in each patient. The average age of the patients was 50.8±7.1 years. In 49 patients, the right shoulder was affected and in the remaining 31 the left side was affected. Before surgery, the patients were suffering from this disease on average for 11.7±10.3 months. The average time to follow-up was 47.2±6.8 months (14 to 60 months). Diabetes mellitus (38%) and history of shoulder trauma (23%) were the most common comorbidities in our patients. We did not find any significant differences between baseline characteristics of diabetics patients with non-diabetics ones. After surgery, the average time to achieve maximum pain improvement and range of motion were 3.6±2.1 and 3.6±2 months, respectively. The VAS score, constant shoulder score, Rowe score, UCLA shoulder score, and DASH score showed significant improvement in shoulder function after surgery, and shoulder range of motion improved in all directions compared to pre-operation range of motion. According to our results, arthroscopic release of recalcitrant frozen shoulder is a valuable modality in treating this disease. This method could decrease pain and improve both subjective and objective mid-term outcomes.

Clinical Outcomes after Arthroscopic Release for Recalcitrant Frozen Shoulder

PubMed Central

Ebrahimzadeh, Mohammad H; Moradi, Ali; Pour, Mostafa Khalili; Moghadam, Mohammad Hallaj; Kachooei, Amir Reza

2014-01-01

Background: To explain the role of arthroscopic release in intractable frozen shoulders. We used different questionnaires and measuring tools to understand whether arthroscopic release is the superior modality to treat patients with intractable frozen shoulders. Methods: Between 2007 and 2013, in a prospective study, we enrolled 80 patients (52 females and 28 males) with recalcitrant frozen shoulder, who underwent arthroscopic release at Ghaem Hospital, a tertiary referral center, in Mashhad, Iran. Before operation, all patients filled out the Disability of Arm, Shoulder and Hand (DASH), Constant, University of California Los Angeles (UCLA), ROWE and Visual Analogue Scale (VAS) for pain questionnaires. We measured the difference in range of motion between both the normal and the frozen shoulders in each patient. Results: The average age of the patients was 50.8±7.1 years. In 49 patients, the right shoulder was affected and in the remaining 31 the left side was affected. Before surgery, the patients were suffering from this disease on average for 11.7±10.3 months. The average time to follow-up was 47.2±6.8 months (14 to 60 months). Diabetes mellitus (38%) and history of shoulder trauma (23%) were the most common comorbidities in our patients. We did not find any significant differences between baseline characteristics of diabetics patients with non-diabetics ones. After surgery, the average time to achieve maximum pain improvement and range of motion were 3.6±2.1 and 3.6±2 months, respectively. The VAS score, constant shoulder score, Rowe score, UCLA shoulder score, and DASH score showed significant improvement in shoulder function after surgery, and shoulder range of motion improved in all directions compared to pre-operation range of motion. Conclusions: According to our results, arthroscopic release of recalcitrant frozen shoulder is a valuable modality in treating this disease. This method could decrease pain and improve both subjective and objective mid

A simple protocol for protein extraction of recalcitrant fruit tissues suitable for 2-DE and MS analysis.

PubMed

Song, Jun; Braun, Gordon; Bevis, Eric; Doncaster, Kristen

2006-08-01

Fruit tissues are considered recalcitrant plant tissue for proteomic analysis. Three phenol-free protein extraction procedures for 2-DE were compared and evaluated on apple fruit proteins. Incorporation of hot SDS buffer, extraction with TCA/acetone precipitation was found to be the most effective protocol. The results from SDS-PAGE and 2-DE analysis showed high quality proteins. More than 500 apple polypeptides were separated on a small scale 2-DE gel. The successful protocol was further tested on banana fruit, in which 504 and 386 proteins were detected in peel and flesh tissues, respectively. To demonstrate the quality of the extracted proteins, several protein spots from apple and banana peels were cut from 2-DE gels, analyzed by MS and have been tentatively identified. The protocol described in this study is a simple procedure which could be routinely used in proteomic studies of many types of recalcitrant fruit tissues.

Date palm waste-derived biochar composites with silica and zeolite: synthesis, characterization and implication for carbon stability and recalcitrant potential.

PubMed

Ahmad, Munir; Ahmad, Mahtab; Usman, Adel R A; Al-Faraj, Abdullah S; Abduljabbar, Adel; Ok, Yong Sik; Al-Wabel, Mohammad I

2017-03-23

Engineered organo-mineral composites were synthesized from date palm waste biochar and silica or zeolite via mechanochemical treatments. Date palm tree rachis (leaves) waste biomass was pre-treated with silica or zeolite minerals via ball milling and sonication prior to pyrolysis at 600 °C. The resultant organo-mineral composites and pristine materials were characterized using X-ray diffraction, thermogravimetric-differential thermal (TG-DTA), Fourier transform infrared, scanning electron microscope analyses and surface area and porosity analyzer to investigate the variations in physiochemical and structural characteristics. Compared to the resultant composites derived from non-milled date palm biomass, ball milling increased surface area, while decreased crystallinity index and effective particle size of the biochar composites. Silica composited biochars were located near origin in the van Krevelen diagram indicating lowest H/C and O/C molar ratios, thus suggesting higher aromaticity and lower polarity compared to other biochars. TGA thermograms indicated highest thermal stability of silica composited biochars. Ash and moisture corrected TGA thermograms were used to calculate recalcitrance index (R 50 ) of the materials, which speculated high degradability of biomass (R 50  < 0.4), minimal degradability of biochars and zeolite composited biochars (0.5 < R 50  < 0.7) and high recalcitrant nature of silica composited biochars (R 50  > 0.7). Silica composited biochars exhibited highest carbon sequestration potential (64.17-95.59%) compared to other biochars. Highest recalcitrance and carbon sequestration potential of silica composited biochars may be attributed to changes in structural arrangements in the silica-biochar complex. Encapsulations of biochar particles with amorphous silica via Si-C bonding may have prevented thermal degradation, subsequently increasing recalcitrance potential of silica composited biochars.

Recalcitrant Nodulocystic Acne in Black Americans: Treatment With Isotretinoin

PubMed Central

Kelly, A. Paul; Sampson, Darlene D.

1987-01-01

The beneficial effects of isotretinoin (Accutane) on severe nodulocystic acne and significant clinical improvement with prolonged remission are well documented in the literature; however, the subjects in these clinical studies are invariably white. The purpose of this study was to evaluate the response of black patients with recalcitrant nodulocystic acne to isotretinoin treatment. Ten black patients, ranging in age from 17 to 34 years, were treated for nodulocystic acne with 1 mg/kg/d of isotretinoin for 20 weeks and followed for an additional six months. Of the ten patients, eight adhered to the treatment regimen and were still in remission six months after completion of isotretinoin therapy. The differences and similarities seen between black patients and white patients with nodulocystic acne are discussed. ImagesFigure 1Figure 2Figure 3 PMID:2963137

Fractional Resurfacing Aiding Photodynamic Therapy of a Recalcitrant Plantar Verruca

PubMed Central

Pope, Amy

2008-01-01

Fractional resurfacing has become a very popular laser modality in recent years, and photodynamic therapy (PDT) has become a mainstay of many practices treating a wide array of clinical entities. In this case report, we describe a recalcitrant verrucous lesion on the foot that is unresponsive to cryotherapy, pulsed dye laser, and pulsed dye laser with PDT. The lesion did, however, respond very well to the use of a fractional laser to enhance the penetration of the PDT photosensitizer and then responded to pulsed dye laser with PDT. Fractional resurfacing prior to PDT may be a novel dermatologic treatment approach, making PDT an even better treatment option in the future. PMID:21103307

Treatment of recalcitrant wastewater from ethanol and citric acid production using the microalga Chlorella vulgaris and the macrophyte Lemna minuscula.

PubMed

Valderrama, Luz T; Del Campo, Claudia M; Rodriguez, Claudia M; de- Bashan, Luz E; Bashan, Yoav

2002-10-01

Laboratory-scale experiments were performed to develop a procedure for biological treatment of recalcitrant anaerobic industrial effluent (from ethanol and citric acid production) using first the microalga Chlorella vulgaris followed by the macrophyte Lemna minuscula. This recalcitrant dark-colored wastewater, containing high levels of organic matter and low pH, prevents the growth of microalgae and macrophytes, and therefore, could not be treated by them. Therefore, the wastewater was diluted to 10% of the original concentration with wash water from the production line. Within 4 days of incubation in the wastewater, C. vulgaris population grew from 5 x 10(5) to 2 x 10(6) cells/mL. This culture reduced ammonium ion (71.6%), phosphorus (28%), and chemical oxygen demand (COD) (61%), and dissolved a floating microbial biofilm after 5 days of incubation. Consequently, L. minuscule was able to grow in the treated wastewater (from 7 to 14 g/bioreactor after 6 days), precipitated the microalgal cells (by shading the culture), and reduced other organic matter and color (up to 52%) after an additional 6 days of incubation. However, L. minuscula did not improve removal of nutrients. This study demonstrates the feasibility of combining microalgae and macrophytes for bioremediation of recalcitrant industrial wastewater.

Degradation of hexane and other recalcitrant hydrocarbons by a novel isolate, Rhodococcus sp. EH831.

PubMed

Lee, Eun-Hee; Kim, Jaisoo; Cho, Kyung-Suk; Ahn, Yun Gyong; Hwang, Geum-Sook

2010-01-01

Hexane, a representative VOC, is used as a solvent for extraction and as an ingredient in gasoline. The degradation of hexane by bacteria is relatively slow due to its low solubility. Moreover, the biodegradation pathway of hexane under aerobic conditions remains to be investigated; therefore, a study relating to aerobic biodegradation mechanisms is required. Consequently, in this study, an effective hexane degrader was isolated and the biodegradation pathway examined for the first time. In addition, the degradation characteristics of a variety of recalcitrant hydrocarbons were qualitatively and quantitatively investigated using the isolate. A hexane-degrading bacterium was isolated from an enrichment culture using petroleum-contaminated soil as an inoculum with hexane as the sole carbon and energy source. The bacterium was also identified using the partial 16S rRNA gene sequence. To test the hexane-degrading capacity of the isolate, 10 ml of an EH831 cell suspension was inoculated into a 600-ml serum bottle with hexane (7.6-75.8 micromol) injected as the sole carbon source. The rates of hexane degradation were determined by analyzing the concentrations of hexane using headspace gas chromatography. In addition, the hexane biodegradation pathway under aerobic conditions was investigated by identifying the metabolites using gas chromatography-mass spectrometry with solid-phase microextraction. 14C-hexane was used to check if EH831 could mineralize hexane in the same experimental system. The degradabilities of other hydrocarbons were examined using EH831 with methanol, ethanol, acetone, cyclohexane, methyl tert-butyl ether (MTBE), dichloromethane (DCM), trichloroethylene, tetrachloroethylene, benzene, toluene, ethylbenzene, xylene (BTEX), pyrene, diesel, lubricant oil, and crude oil as sole carbon sources. A bacterium, EH831, was isolated from the enriched hexane-degrading consortium, which was able to degrade hexane and various hydrocarbons, including alcohols

Nanometer-scale structure of alkali-soluble bio-macromolecules of maize plant residues explains their recalcitrance in soil.

PubMed

Adani, Fabrizio; Salati, Silvia; Spagnol, Manuela; Tambone, Fulvia; Genevini, Pierluigi; Pilu, Roberto; Nierop, Klaas G J

2009-07-01

The quantity and quality of plant litter in the soil play an important role in the soil organic matter balance. Besides other pedo-climatic aspects, the content of recalcitrant molecules of plant residues and their chemical composition play a major role in the preservation of plant residues. In this study, we report that intrinsically resistant alkali-soluble bio-macromolecules extracted from maize plant (plant-humic acid) (plant-HA) contribute directly to the soil organic matter (OM) by its addition and conservation in the soil. Furthermore, we also observed that a high syringyl/guaiacyl (S/G) ratio in the lignin residues comprising the plant tissue, which modifies the microscopic structure of the alkali-soluble plant biopolymers, enhances their recalcitrance because of lower accessibility of molecules to degrading enzymes. These results are in agreement with a recent study, which showed that the humic substance of soil consists of a mixture of identifiable biopolymers obtained directly from plant tissues that are added annually by maize plant residues.

Systems and synthetic biology approaches to alter plant cell walls and reduce biomass recalcitrance

DOE PAGES

Kalluri, Udaya C.; Yin, Hengfu; Yang, Xiaohan; ...

2014-11-03

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host thatmore » carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Finally, synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance.« less

Systems and synthetic biology approaches to alter plant cell walls and reduce biomass recalcitrance

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

Kalluri, Udaya C.; Yin, Hengfu; Yang, Xiaohan

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host thatmore » carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Finally, synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance.« less

Seed-to-seed-to-seed growth and development of Arabidopsis in microgravity.

PubMed

Link, Bruce M; Busse, James S; Stankovic, Bratislav

2014-10-01

Arabidopsis thaliana was grown from seed to seed wholly in microgravity on the International Space Station. Arabidopsis plants were germinated, grown, and maintained inside a growth chamber prior to returning to Earth. Some of these seeds were used in a subsequent experiment to successfully produce a second (back-to-back) generation of microgravity-grown Arabidopsis. In general, plant growth and development in microgravity proceeded similarly to those of the ground controls, which were grown in an identical chamber. Morphologically, the most striking feature of space-grown Arabidopsis was that the secondary inflorescence branches and siliques formed nearly perpendicular angles to the inflorescence stems. The branches grew out perpendicularly to the main inflorescence stem, indicating that gravity was the key determinant of branch and silique angle and that light had either no role or a secondary role in Arabidopsis branch and silique orientation. Seed protein bodies were 55% smaller in space seed than in controls, but protein assays showed only a 9% reduction in seed protein content. Germination rates for space-produced seed were 92%, indicating that the seeds developed in microgravity were healthy and viable. Gravity is not necessary for seed-to-seed growth of plants, though it plays a direct role in plant form and may influence seed reserves.

Complete remission of recalcitrant genital warts with a combination approach of surgical debulking and oral isotretinoin in a patient with systemic lupus erythematosus.

PubMed

Yew, Yik Weng; Pan, Jiun Yit

2014-01-01

Genital warts in immunocompromised patients can be extensive and recalcitrant to treatment. We report a case of recalcitrant genital warts in a female patient with systemic lupus erythematosus (SLE), who achieved complete remission with a combination approach of surgical debulking and oral isotretinoin at an initial dose of 20 mg/day with a gradual taper of dose over 8 months. She had previously been treated with a combination of topical imiquimod cream and regular fortnightly liquid nitrogen. Although there was partial response, there was no complete clearance. Her condition worsened after topical imiquimod cream was stopped because of her pregnancy. She underwent a combination approach of surgical debulking and oral isotretinoin after her delivery and achieved full clearance for more than 2 years duration. Oral isotretinoin, especially in the treatment of recalcitrant genital warts, is a valuable and feasible option when other more conventional treatment methods have failed or are not possible. It can be used alone or in combination with other local or physical treatment methods. © 2013 Wiley Periodicals, Inc.

Seed-to-Seed-to-Seed Growth and Development of Arabidopsis in Microgravity

PubMed Central

Link, Bruce M.; Busse, James S.

2014-01-01

Abstract Arabidopsis thaliana was grown from seed to seed wholly in microgravity on the International Space Station. Arabidopsis plants were germinated, grown, and maintained inside a growth chamber prior to returning to Earth. Some of these seeds were used in a subsequent experiment to successfully produce a second (back-to-back) generation of microgravity-grown Arabidopsis. In general, plant growth and development in microgravity proceeded similarly to those of the ground controls, which were grown in an identical chamber. Morphologically, the most striking feature of space-grown Arabidopsis was that the secondary inflorescence branches and siliques formed nearly perpendicular angles to the inflorescence stems. The branches grew out perpendicularly to the main inflorescence stem, indicating that gravity was the key determinant of branch and silique angle and that light had either no role or a secondary role in Arabidopsis branch and silique orientation. Seed protein bodies were 55% smaller in space seed than in controls, but protein assays showed only a 9% reduction in seed protein content. Germination rates for space-produced seed were 92%, indicating that the seeds developed in microgravity were healthy and viable. Gravity is not necessary for seed-to-seed growth of plants, though it plays a direct role in plant form and may influence seed reserves. Key Words: Arabidopsis—Branch—Inflorescence—Microgravity—Morphology—Seed—Space. Astrobiology 14, 866–875. PMID:25317938

Oral Azathioprine for Recalcitrant Pediatric Atopic Dermatitis: Clinical Response and Thiopurine Monitoring

PubMed Central

Caufield, Maura; Tom, Wynnis L.

2012-01-01

Background Azathioprine is prescribed as a corticosteroid-sparing agent for many inflammatory conditions, including refractory atopic dermatitis (AD). There is limited prospective data on its appropriate use and monitoring for children with AD. Objectives This study was designed to assess clinical response to azathioprine, determine the necessity for repeat measurement of thiopurine methyltransferase (TPMT) activity during treatment, and test the utility of measuring levels of the metabolites 6-thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine (6-MMP). Methods Twelve children with severe, recalcitrant AD were treated with oral azathioprine and followed prospectively. Disease severity was determined by the SCORing Atopic Dermatitis Index. Baseline TPMT activity was measured and this was repeated along with 6-TGN and 6-MMP measurement at times of stable improvement, inadequate response, or change in response. Results Azathioprine therapy was associated with clinical improvement in all but one subject. There were few adverse effects. Three subjects showed a significant change in TPMT activity during treatment: two had a mild decrease and one demonstrated enzyme inducibility with an increase from the intermediate to the normal activity range. These changes, but not 6-TGN or 6-MMP levels, inversely correlated with the clinical response to therapy. Limitations Small sample size Conclusions Azathioprine can be of benefit in the treatment of recalcitrant pediatric AD. Repeat assessment of TPMT activity may be helpful for evaluation of non–response or change in response and warrants further study. In contrast, measurement of thiopurine metabolites during treatment was not clinically useful. PMID:22892285

Differential seed handling by two African primates affects seed fate and establishment of large-seeded trees

NASA Astrophysics Data System (ADS)

Gross-Camp, Nicole D.; Kaplin, Beth A.

2011-11-01

We examined the influence of seed handling by two semi-terrestrial African forest primates, chimpanzees ( Pan troglodytes) and l'Hoest's monkeys ( Cercopithecus lhoesti), on the fate of large-seeded tree species in an afromontane forest. Chimpanzees and l'Hoest's monkeys dispersed eleven seed species over one year, with quantity and quality of dispersal varying through time. Primates differed in their seed handling behaviors with chimpanzees defecating large seeds (>0.5 cm) significantly more than l'Hoest's. Furthermore, they exhibited different oral-processing techniques with chimpanzees discarding wadges containing many seeds and l'Hoest's monkeys spitting single seeds. A PCA examined the relationship between microhabitat characteristics and the site where primates deposited seeds. The first two components explained almost half of the observed variation. Microhabitat characteristics associated with sites where seeds were defecated had little overlap with those characteristics describing where spit seeds arrived, suggesting that seed handling in part determines the location where seeds are deposited. We monitored a total of 552 seed depositions through time, recording seed persistence, germination, and establishment. Defecations were deposited significantly farther from an adult conspecific than orally-discarded seeds where they experienced the greatest persistence but poorest establishment. In contrast, spit seeds were deposited closest to an adult conspecific but experienced the highest seed establishment rates. We used experimental plots to examine the relationship between seed handling, deposition site, and seed fate. We found a significant difference in seed handling and fate, with undispersed seeds in whole fruits experiencing the lowest establishment rates. Seed germination differed by habitat type with open forest experiencing the highest rates of germination. Our results highlight the relationship between primate seed handling and deposition site and seed

Stimulation of oxygen to bioanode for energy recovery from recalcitrant organic matter aniline in microbial fuel cells (MFCs).

PubMed

Cheng, Hao-Yi; Liang, Bin; Mu, Yang; Cui, Min-Hua; Li, Kun; Wu, Wei-Min; Wang, Ai-Jie

2015-09-15

The challenge of energy generation from biodegradation of recalcitrant organics in microbial fuel cells (MFCs) is mainly attributed to their persistence to degradation under anaerobic condition in anode chamber of MFCs. In this work, we demonstrated that electricity generation from aniline, a typical recalcitrant organic matter under anaerobic condition was remarkably facilitated by employing oxygen into bioanode of MFCs. By exposing bioanode to air, electrons of 47.2 ± 6.9 C were recovered with aniline removal efficiency of 91.2 ± 2.2% in 144 h. Limited oxygen supply (the anodic headspace was initially filled with air and then closed) resulted in the decrease of electrons recovery and aniline removal efficiency by 52.5 ± 9.4% and 74.2 ± 2.1%, respectively, and further decline by respective 64.3 ± 4.5% and 82.7 ± 1.0% occurred under anaerobic condition. Community analysis showed that anode biofilm was predominated by several aerobic aniline degrading bacteria (AADB) and anode-respiration bacteria (ARB), which likely cooperated with each other and finally featured the energy recovery from aniline. Cyclic voltammetry indicated that anodic bacteria transferred electrons to anode mainly through electron shuttle. This study provided a new sight to acquaint us with the positive role of oxygen in biodegradation of recalcitrant organics on anode as well as electricity generation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Global latitudinal trends in peat recalcitrance quantified with calibrated FTIR spectroscopy

NASA Astrophysics Data System (ADS)

Hodgkins, S. B.; Richardson, C. J.; Dommain, R.; Wang, H.; Glaser, P. H.; Verbeke, B. A.; Rogers, K.; Winkler, B. R.; Missilmani, M.; Flanagan, N. E.; Ho, M.; Hoyt, A.; Harvey, C. F.; Cobb, A.; Rich, V. I.; Vining, S. R.; Hough, M.; Saleska, S. R.; Podgorski, D. C.; Tfaily, M. M.; Wilson, R.; Holmes, B.; de La Cruz, F.; Toufaily, J.; Hamdan, R.; Cooper, W. T.; Chanton, J.

2017-12-01

Peatlands are a major global carbon reservoir (528-600 Pg). Most peat is found at high latitudes, where organic matter decomposition is slowed by cold temperatures and water-saturated conditions. Nonetheless, a significant portion of global peatland carbon (10-30%) is in tropical peatlands. The factors that allow peat accumulation in warm climates remain uncertain, raising the question of whether these factors may preserve peat in boreal regions as they warm. In this study, we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Carbohydrate and aromatic contents were estimated based on a newly-developed analysis method for Fourier transform infrared (FTIR) spectra. In this method, peaks are baseline-corrected and normalized to the integrated spectral area using an automated R script, then calibrated to known concentrations using standards. This technique showed trends that were in agreement with those seen with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and 13C-NMR spectroscopy. Along the latitudinal transect, we found that near-surface (sub)tropical peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, leading to recalcitrance that allows (sub)tropical peat to persist despite warm temperatures. The chemistry of (sub)tropical peat reflects a combination of recalcitrant plant inputs, and more extensive humification driven by higher temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat deposits, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable in the face of temperature increases up to 9 °C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.

Topical Colloidal Silver for the Treatment of Recalcitrant Chronic Rhinosinusitis

PubMed Central

Ooi, Mian L.; Richter, Katharina; Bennett, Catherine; Macias-Valle, Luis; Vreugde, Sarah; Psaltis, Alkis J.; Wormald, Peter-John

2018-01-01

Background: The management of recalcitrant chronic rhinosinusitis (CRS) is challenged by difficult-to-treat polymicrobial biofilms and multidrug resistant bacteria. This has led to the search for broad-spectrum non-antibiotic antimicrobial therapies. Colloidal silver (CS) has significant antibiofilm activity in vitro and in vivo against S. aureus, MRSA, and P. aeruginosa. However, due to the lack of scientific efficacy, it is only currently used as an alternative medicine. This is the first study looking at the safety and efficacy of CS in recalcitrant CRS. Methods: Patients were included when they had previously undergone endoscopic sinus surgery and presented with signs and symptoms of sinus infection with positive bacterial cultures. Twenty-two patients completed the study. Patients were allocated to 10–14 days of culture directed oral antibiotics with twice daily saline rinses (n = 11) or 10 days of twice daily 0.015 mg/mL CS rinses (n = 11). Safety observations included pre- and post-treatment serum silver levels, University of Pennsylvania Smell Identification Test (UPSIT) and adverse event (AE) reporting. Efficacy was assessed comparing microbiology results, Lund Kennedy Scores (LKS) and symptom scores using Visual Analog Scale (VAS) and Sino-Nasal Outcome Test (SNOT-22). Results: CS demonstrated good safety profile with no major adverse events, no changes in UPSIT and transient serum silver level changes in 4 patients. CS patients had 1/11 (9.09%) negative cultures, compared to 2/11 (18.18%) in the control group upon completion of the study. Whilst not statistically significant, both groups showed similar improvement in symptoms and endoscopic scores. Conclusion: This study concludes that twice daily CS (0.015 mg/mL) sinonasal rinses for 10 days is safe but not superior to culture-directed oral antibiotics. Further studies including more patients and looking at longer treatment or improving the tonicity of the solution for better tolerability should be

The outcome of endoscopy for recalcitrant greater trochanteric pain syndrome.

PubMed

Drummond, James; Fary, Camdon; Tran, Phong

2016-11-01

Greater trochanteric pain syndrome (GTPS), previously referred as trochanteric bursitis, is a debilitating condition characterised by chronic lateral hip pain. The syndrome is thought to relate to gluteal tendinopathy, with most cases responding to non-operative treatment. A number of open and endoscopic surgical techniques targeting the iliotibial band, trochanteric bursa and gluteal tendons have, however, been described for severe recalcitrant cases. We report the outcomes of one such endoscopic approach here. We retrospectively reviewed 49 patients (57 operations) who had undergone endoscopic longitudinal vertical iliotibial band release and trochanteric bursectomy. Inclusion criteria included diagnosed GTPS with a minimum of six months of non-operative treatment. Exclusion criteria included concomitant intra- or extra-articular hip pathology and previous hip surgery including total hip arthroplasty. Outcomes were assessed using the Visual Analogue Scale, Oxford hip Score and International Hip Outcome Tool (iHOT-33). The series included 42 females and 7 males with a mean age of 65.0 years (26.7-88.6). Mean follow-up time was 20.7 months (5.3-41.2). Eight patients had full thickness gluteal tendon tears, of which 7 were repaired. Adjuvant PRP was injected intraoperatively in 38 of 57 operations (67.2 %). At follow-up, overall mean Visual Analogue Scale values had decreased from 7.8 to 2.8 (p < 0.001), Oxford hip Scores had increased from 20.4 to 37.3 (p < 0.001) and iHOT-33 scores had increased from 23.8 to 70.2 (p < 0.001). Of the 57 operations performed, patients reported feeling very satisfied with the surgical outcome in 28 operations (49.1 %), satisfied in 17 operations (29.8 %) and less than satisfied in 12 operations (21.1 %). While the majority of patients with GTPS will improve with non-operative management, endoscopic iliotibial band release, trochanteric bursectomy and gluteal tendon repair is a safe and effective treatment for severe

Analysis of carbon functional groups in mobile humic acid and recalcitrant calcium humate extracted from eight US soils

USDA-ARS?s Scientific Manuscript database

Solid state 13C nuclear magnetic resonance (NMR) spectroscopy is a common tool to study the structure of soil humic fractions; however, knowledge regarding carbon structural relationships in humic fractions is limited. In this study, mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) fr...

Transpositional reactivation of the Dart transposon family in rice lines derived from introgressive hybridization with Zizania latifolia.

PubMed

Wang, Ningning; Wang, Hongyan; Wang, Hui; Zhang, Di; Wu, Ying; Ou, Xiufang; Liu, Shuang; Dong, Zhenying; Liu, Bao

2010-08-26

It is widely recognized that interspecific hybridization may induce "genome shock", and lead to genetic and epigenetic instabilities in the resultant hybrids and/or backcrossed introgressants. A prominent component involved in the genome shock is reactivation of cryptic transposable elements (TEs) in the hybrid genome, which is often associated with alteration in the elements' epigenetic modifications like cytosine DNA methylation. We have previously reported that introgressants derived from hybridization between Oryza sativa (rice) and Zizania latifolia manifested substantial methylation re-patterning and rampant mobilization of two TEs, a copia retrotransposon Tos17 and a MITE mPing. It was not known however whether other types of TEs had also been transpositionally reactivated in these introgressants, their relevance to alteration in cytosine methylation, and their impact on expression of adjacent cellular genes. We document in this study that the Dart TE family was transpositionally reactivated followed by stabilization in all three studied introgressants (RZ1, RZ2 and RZ35) derived from introgressive hybridization between rice (cv. Matsumae) and Z. latifolia, while the TEs remained quiescent in the recipient rice genome. Transposon-display (TD) and sequencing verified the element's mobility and mapped the excisions and re-insertions to the rice chromosomes. Methylation-sensitive Southern blotting showed that the Dart TEs were heavily methylated along their entire length, and moderate alteration in cytosine methylation patterns occurred in the introgressants relative to their rice parental line. Real-time qRT-PCR quantification on the relative transcript abundance of six single-copy genes flanking the newly excised or inserted Dart-related TE copies indicated that whereas marked difference in the expression of all four genes in both tissues (leaf and root) were detected between the introgressants and their rice parental line under both normal and various stress

Treatment of recalcitrant cicatricial pemphigoid with the tumor necrosis factor alpha antagonist etanercept.

PubMed

Sacher, Christopher; Rubbert, Andrea; König, Cathrin; Scharffetter-Kochanek, Karin; Krieg, Thomas; Hunzelmann, Nicolas

2002-01-01

The treatment of cicatricial pemphigoid is generally regarded as difficult and usually relies on individual clinical experience. Corticosteroids, as drugs of first choice, often have to be combined with steroid-sparing agents to prevent hazardous, long-term side effects. We describe a 72-year-old woman with long-standing cicatricial pemphigoid recalcitrant to established treatment regimens who responded rapidly and lastingly to therapy with the tumor necrosis factor alpha antagonist etanercept. To our knowledge, this is the first report of its use in the treatment of a bullous autoimmune disease.

Results of operative treatment for recalcitrant retrocalcaneal bursitis and midportion Achilles tendinopathy in athletes.

PubMed

Lohrer, Heinz; Nauck, Tanja

2014-08-01

The results of operative treatment for recalcitrant midportion Achilles tendinopathy and recalcitrant retrocalcaneal bursitis were evaluated using the patient administered, disease specific, and validated VISA-A-G questionnaire. A cohort of 89 patients was prospectively followed. These patients underwent operations for sport induced midportion Achilles tendinopathy (39 procedures) or retrocalcaneal bursitis (55 procedures). Depending on the individual intraoperative findings the patients of either disease were treated with two respective operative modifications (tendon repair or no tendon repair). Preoperative and follow-up status (3, 6, and 12 months) were investigated using the VISA-A-G questionnaire. Preoperatively, the four groups scored from 37.0 ± 17.6 to 45.9 ± 15.2 (p = 0.376-0.993) on the VISA-A-G questionnaire. Six and 12 months postoperatively, the VISA-A-G scores improved significantly (p < 0.001). Twelve months postoperatively, the groups' scores were not different (p = 0.100-0.952) and ranged from 80.8 ± 17.9 to 90.3 ± 10.6. Retrocalcaneal bursitis and midportion Achilles tendinopathy responded equally well to operative treatment. When repaired, additional tendon lesions did not influence this result. We demand to differentiate not only between midportion Achilles tendinopathy and retrocalcaneal bursitis but also to identify additional Achilles tendon lesions to specifically address these lesions during operative procedures.

Improving survival and storage stability of bacteria recalcitrant to freeze-drying: a coordinated study by European culture collections.

PubMed

Peiren, Jindrich; Buyse, Joke; De Vos, Paul; Lang, Elke; Clermont, Dominique; Hamon, Sylviane; Bégaud, Evelyne; Bizet, Chantal; Pascual, Javier; Ruvira, María A; Macián, M Carmen; Arahal, David R

2015-04-01

The objective of this study is to improve the viability after freeze-drying and during storage of delicate or recalcitrant strains safeguarded at biological resource centers. To achieve this objective, a joint experimental strategy was established among the different involved partner collections of the EMbaRC project ( www.embarc.eu ). Five bacterial strains considered as recalcitrant to freeze-drying were subjected to a standardized freeze-drying protocol and to seven agreed protocol variants. Viability of these strains was determined before and after freeze-drying (within 1 week, after 6 and 12 months, and after accelerated storage) for each of the protocols. Furthermore, strains were exchanged between partners to perform experiments with different freeze-dryer-dependent parameters. Of all tested variables, choice of the lyoprotectant had the biggest impact on viability after freeze-drying and during storage. For nearly all tested strains, skim milk as lyoprotectant resulted in lowest viability after freeze-drying and storage. On the other hand, best freeze-drying and storage conditions were strain and device dependent. For Aeromonas salmonicida CECT 894(T), best survival was obtained when horse serum supplemented with trehalose was used as lyoprotectant, while Aliivibrio fischeri LMG 4414(T) should be freeze-dried in skim milk supplemented with marine broth in a 1:1 ratio. Freeze-drying Campylobacter fetus CIP 53.96(T) using skim milk supplemented with trehalose as lyoprotectant resulted in best recovery. Xanthomonas fragariae DSM 3587(T) expressed high viability after freeze-drying and storage for all tested lyoprotectants and could not be considered as recalcitrant. In contrary, Flavobacterium columnare LMG 10406(T) did not survive the freeze-drying process under all tested conditions.

Seed harvesting is influenced by associational effects in mixed seed neighbourhoods, not just by seed density

USGS Publications Warehouse

Ostoja, Steven M.; Schupp, Eugene W.; Durham, Susan; Klinger, Robert C.

2013-01-01

Rodents frequently forage in a density-dependent manner, increasing harvesting in patches with greater seed densities. Although seldom considered, seed harvesting may also depend on the species identities of other individuals in the seed neighbourhood. When the seed harvest of a focal species increases in association with another seed species, the focal species suffers from Associational Susceptibility. In contrast, if seeds of the focal species are harvested less when in association with a second species, the focal species benefits from Associational Resistance.To evaluate density dependence and associational effects among seeds in mixtures, we conducted seed removal experiments using a completely additive design patterned after a two-species competition experiment using seeds of either Achnatherum hymenoides(Indian ricegrass), Leymus cinereus (basin wildrye) or Pseudoroegneria spicata (bluebunch wheatgrass), all native perennial grasses, combined with seeds of Bromus tectorum(cheatgrass), a non-native annual grass. The experiment involved placing five fixed quantities of the native seeds mixed with five fixed quantities of B. tectorum seeds in a factorial design, resulting in 35 seed mixture combinations. The seed-eating rodent community at our study sites, in order of abundance, is composed of Peromyscus maniculatus (North American deer mouse), Dipodomys ordii (Ord's kangaroo rat) and Perognathus parvus (Great Basin pocket mouse).Native seed harvesting was density dependent, with a greater proportion of seeds being harvested as density increased. In the mixed density model, the presence of B. tectorumdid not affect harvest of any of the native species' seeds when analysed individually. However, when all three native species were analysed together, increasing quantities of B. tectorum resulted in reduced harvest of native seeds, demonstrating weak but significant Associational Resistance. In contrast, harvest of B. tectorum seeds increased

Medial maxillectomy in recalcitrant sinusitis: when, why and how?

PubMed

Konstantinidis, Iordanis; Constantinidis, Jannis

2014-02-01

We reviewed all journal articles relevant to endoscopic medial maxillectomy in patients with recalcitrant chronic maxillary sinusitis in order to present all indications, the underlying pathophysiology and the developed surgical techniques. Despite the high success rate of middle meatal antrostomy, cases with persistent maxillary sinus disease exist and often need a more extended endoscopic procedure for the better control of the disease. Such surgical option uses gravity for better sinus drainage and offers better saline irrigation, local application of medications and follow-up inspection. An endoscopic medial maxillectomy and its modified forms offer a wider surgical field and access to all 'difficult' areas of the maxillary sinus. Patients with previous limited endoscopic sinus surgery or extended open surgery, cystic fibrosis, extensive mucoceles, allergic fungal sinusitis, odontogenic infections, foreign bodies and so on may suffer from recurrent disease requiring an endoscopic medial maxillectomy. Depending on the disease, various modifications of the procedure can be performed preserving the anterior buttress, nasolacrimal duct and inferior turbinate if possible.

Saccharification of recalcitrant biomass and integration options for lignocellulosic sugars from Catchlight Energy's sugar process (CLE Sugar).

PubMed

Gao, Johnway; Anderson, Dwight; Levie, Benjamin

2013-01-28

Woody biomass is one of the most abundant biomass feedstocks, besides agriculture residuals in the United States. The sustainable harvest residuals and thinnings alone are estimated at about 75 million tons/year. These forest residuals and thinnings could produce the equivalent of 5 billion gallons of lignocellulosic ethanol annually. Softwood biomass is the most recalcitrant biomass in pretreatment before an enzymatic hydrolysis. To utilize the most recalcitrant lignocellulosic materials, an efficient, industrially scalable and cost effective pretreatment method is needed. Obtaining a high yield of sugar from recalcitrant biomass generally requires a high severity of pretreatment with aggressive chemistry, followed by extensive conditioning, and large doses of enzymes. Catchlight Energy's Sugar process, CLE Sugar, uses a low intensity, high throughput variation of bisulfite pulping to pretreat recalcitrant biomass, such as softwood forest residuals. By leveraging well-proven bisulfite technology and the rapid progress of enzyme suppliers, CLE Sugar can achieve a high yield of total biomass carbohydrate conversion to monomeric lignocellulosic sugars. For example, 85.8% of biomass carbohydrates are saccharified for un-debarked Loblolly pine chips (softwood), and 94.0% for debarked maple chips (hardwood). Furan compound formation was 1.29% of biomass feedstock for Loblolly pine and 1.10% for maple. At 17% solids hydrolysis of pretreated softwood, an enzyme dose of 0.075 g Sigma enzyme mixture/g dry pretreated (unwashed) biomass was needed to achieve 8.1% total sugar titer in the hydrolysate and an overall prehydrolysate liquor plus enzymatic hydrolysis conversion yield of 76.6%. At a much lower enzyme dosage of 0.044 g CTec2 enzyme product/g dry (unwashed) pretreated softwood, hydrolysis at 17% solids achieved 9.2% total sugar titer in the hydrolysate with an overall sugar yield of 85.0% in the combined prehydrolysate liquor and enzymatic hydrolysate. CLE Sugar has

Surgery for Patients With Recalcitrant Plantar Fasciitis

PubMed Central

Wheeler, Patrick; Boyd, Kevin; Shipton, Mary

2014-01-01

Background: Plantar fasciitis is a common cause of foot pain, and although many episodes are self-limiting with short duration, 10% leave chronic symptoms. Recalcitrant cases can be managed surgically, with studies demonstrating good results in the short term but uncertainties over longer term outcomes. Purpose: To assess the outcome following surgical intervention for patients with plantar fasciitis. Study Design: Case series; Level of evidence, 4. Methods: Seventy-nine patients were identified from operative diaries undergoing plantar fasciotomy surgery between 1993 and 2009. They were contacted to investigate long-term results using self-reported outcome measures. Results: Sixty-eight responses were received (86% response rate), with an average of 7 years (range, 1-15 years) of follow-up. Patients reported an average reduction in pain by visual analog scale of 79%, and 84% of patients were happy with the surgical results. Greater success was achieved in patients with shorter duration of symptoms preoperatively. No deterioration in success was seen over time. Conclusion: Plantar fasciotomy surgery for plantar fasciitis remains controversial, with biomechanical arguments against surgery; however, this article reports good success following surgery over a long follow-up period. The results of current operative techniques need to be fully investigated for longer term success, as do the outcomes of newer nonoperative management strategies. PMID:26535314

Efficiency of seed production in southern pine seed orchards

Treesearch

David L. Bramlett

1977-01-01

Seed production in southern pine seed orchards can be evaluated by estimating the efficiency of four separate stages of cone, seed, and seedling development. Calculated values are: cone efficiency (CE), the ratio of mature cones to the initial flower crop; seed efficiency (SE), the ratio of filled seeds per cone to the seed potential; extraction efficiency (EE), the...

Beneficial effects of topical tacrolimus on recalcitrant erosions of pemphigus vulgaris.

PubMed

Gach, J E; Ilchyshyn, A

2004-05-01

We report a case of pemphigus vulgaris in which a recalcitrant area of erosion on the cheek cleared only when topical tacrolimus was used in addition to a regime of systemic therapy consisting of cyclophosphamide and prednisolone. Clinical improvement occurred within 10 days of applying topical tacrolimus with healing of erosions and reduction in pain and burning sensations. Topical tacrolimus may inhibit local activation of T lymphocytes through altered expression of cytokines such as interleukin-1, -4 and -5, tumour necrosis factor-alpha and interferon-gamma. Some of these cytokines may also contribute directly to increasing keratinocyte fragility in the aetiology of pemphigus vulgaris erosions. This case illustrates that topical tacrolimus may be a useful adjunct in the management of patients with pemphigus vulgaris.

A role for seed storage proteins in Arabidopsis seed longevity

PubMed Central

Nguyen, Thu-Phuong; Cueff, Gwendal; Hegedus, Dwayne D; Rajjou, Loïc; Bentsink, Leónie

2015-01-01

Proteomics approaches have been a useful tool for determining the biological roles and functions of individual proteins and identifying the molecular mechanisms that govern seed germination, vigour and viability in response to ageing. In this work the dry seed proteome of four Arabidopsis thaliana genotypes, that carry introgression fragments at the position of seed longevity quantitative trait loci and as a result display different levels of seed longevity, was investigated. Seeds at two physiological states, after-ripened seeds that had the full germination ability and aged (stored) seeds of which the germination ability was severely reduced, were compared. Aged dry seed proteomes were markedly different from the after-ripened and reflected the seed longevity level of the four genotypes, despite the fact that dry seeds are metabolically quiescent. Results confirmed the role of antioxidant systems, notably vitamin E, and indicated that protection and maintenance of the translation machinery and energy pathways are essential for seed longevity. Moreover, a new role for seed storage proteins (SSPs) was identified in dry seeds during ageing. Cruciferins (CRUs) are the most abundant SSPs in Arabidopsis and seeds of a triple mutant for three CRU isoforms (crua crub cruc) were more sensitive to artificial ageing and their seed proteins were highly oxidized compared with wild-type seeds. These results confirm that oxidation is involved in seed deterioration and that SSPs buffer the seed from oxidative stress, thus protecting important proteins required for seed germination and seedling formation. PMID:26184996

Role of continuous subcutaneous insulin infusion in patients with recalcitrant diabetes in South India.

PubMed

Sudhakaran, Chidambarann; Anjana, Ranjit Mohan; Rao, Kavitha; Unnikrishnan, Ranjit; Suresh, Thangamani; Mohan, Viswanathan

2009-11-01

We aimed to assess the effect of continuous subcutaneous insulin infusion (CSII) therapy in patients with "recalcitrant diabetes" whose glycemia had not been controlled adequately with multiple daily injections of insulin or insulin plus oral hypoglycemic agents. We retrospectively analyzed the medical records of patients with diabetes who were initiated on insulin pump therapy at our center in India between 2002 and 2007. Data analysis included fasting and postprandial blood glucose and glycated hemoglobin (HbA1c) values, insulin requirement, body weight, and the occurrence of hypoglycemia and diabetic ketoacidosis. We studied 33 patients with diabetes (type 1 [n = 17] and type 2 [n = 16]) who were on CSII therapy for a mean duration of 3.4 years. A statistically significant reduction in HbA1c was found after initiating CSII (prepump 10.7% vs. postpump 8.3%, P < 0.001). The reduction was greater in type 1 patients (10.6 +/- 2.1 vs. 8.0 +/- 1.6%) than in type 2 patients (11.0 +/- 2.1 vs. 8.8 +/- 1.4%). There was a reduction in frequency of severe hypoglycemia after starting the CSII pump, and there were no instances of diabetic ketoacidosis. Although HbA1c levels did not reach optimal targets, our data indicate that CSII is an effective therapy for patients with diabetes having recalcitrant diabetes who can afford this treatment and whose glycemia is poorly controlled with conventional therapies.

An in-depth understanding of biomass recalcitrance using natural poplar variants as the feedstock

DOE PAGES

Meng, Xianzhi; Pu, Yunqiao; Yoo, Chang Geun; ...

2016-12-12

Here, in an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons’ stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg gmore » $$–1\\atop{biomass}$$ as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.« less

An in-depth understanding of biomass recalcitrance using natural poplar variants as the feedstock

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

Meng, Xianzhi; Pu, Yunqiao; Yoo, Chang Geun

Here, in an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons’ stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg gmore » $$–1\\atop{biomass}$$ as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.« less

Systems and synthetic biology approaches to alter plant cell walls and reduce biomass recalcitrance.

PubMed

Kalluri, Udaya C; Yin, Hengfu; Yang, Xiaohan; Davison, Brian H

2014-12-01

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host that carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Rapid and Efficient Isolation of High-Quality Small RNAs from Recalcitrant Plant Species Rich in Polyphenols and Polysaccharides

PubMed Central

Pu, Jinji; Guo, Jianrong; Fan, Zaifeng

2014-01-01

Small RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are important regulators of plant development and gene expression. The acquisition of high-quality small RNAs is the first step in the study of its expression and function analysis, yet the extraction method of small RNAs in recalcitrant plant tissues with various secondary metabolites is not well established, especially for tropical and subtropical plant species rich in polysaccharides and polyphenols. Here, we developed a simple and efficient method for high quality small RNAs extraction from recalcitrant plant species. Prior to RNA isolation, a precursory step with a CTAB-PVPP buffer system could efficiently remove compounds and secondary metabolites interfering with RNAs from homogenized lysates. Then, total RNAs were extracted by Trizol reagents followed by a differential precipitation of high-molecular-weight (HMW) RNAs using polyethylene glycol (PEG) 8000. Finally, small RNAs could be easily recovered from supernatant by ethanol precipitation without extra elimination steps. The isolated small RNAs from papaya showed high quality through a clear background on gel and a distinct northern blotting signal with miR159a probe, compared with other published protocols. Additionally, the small RNAs extracted from papaya were successfully used for validation of both predicted miRNAs and the putative conserved tasiARFs. Furthermore, the extraction method described here was also tested with several other subtropical and tropical plant tissues. The purity of the isolated small RNAs was sufficient for such applications as end-point stem-loop RT-PCR and northern blotting analysis, respectively. The simple and feasible extraction method reported here is expected to have excellent potential for isolation of small RNAs from recalcitrant plant tissues rich in polyphenols and polysaccharides. PMID:24787387

Evaluation of mountain beetle-infested lodgepole pine for cellulosic ethanol production by sulfite pretreatment to overcome recalcitrance of lignocellulose

Treesearch

X. Luo; R. Gleisner; S. Tian; J. Negron; W. Zhu; E. Horn; X. J. Pan; J. Y. Zhu

2010-01-01

The potentials of deteriorated mountain pine beetle (Dendroctonus ponderosae)-killed lodgepole pine (Pinus contorta) trees for cellulosic ethanol production were evaluated using the sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) process. The trees were harvested from two sites in the United States Arapaho-Roosevelt National Forest, Colorado....

Cellulose-Hemicellulose Interactions at Elevated Temperatures Increase Cellulose Recalcitrance to Biological Conversion

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

Mittal, Ashutosh; Himmel, Michael E; Kumar, Rajeev

It has been previously shown that cellulose-lignin droplets' strong interactions, resulting from lignin coalescence and redisposition on cellulose surface during thermochemical pretreatments, increase cellulose recalcitrance to biological conversion, especially at commercially viable low enzyme loadings. However, information on the impact of cellulose-hemicellulose interactions on cellulose recalcitrance following relevant pretreatment conditions are scarce. Here, to investigate the effects of plausible hemicellulose precipitation and re-association with cellulose on cellulose conversion, different pretreatments were applied to pure Avicel(R) PH101 cellulose alone and Avicel mixed with model hemicellulose compounds followed by enzymatic hydrolysis of resulting solids at both low and high enzyme loadings. Solidsmore » produced by pretreatment of Avicel mixed with hemicelluloses (AMH) were found to contain about 2 to 14.6% of exogenous, precipitated hemicelluloses and showed a remarkably much lower digestibility (up to 60%) than their respective controls. However, the exogenous hemicellulosic residues that associated with Avicel following high temperature pretreatments resulted in greater losses in cellulose conversion than those formed at low temperatures, suggesting that temperature plays a strong role in the strength of cellulose-hemicellulose association. Molecular dynamics simulations of hemicellulosic xylan and cellulose were found to further support this temperature effect as the xylan-cellulose interactions were found to substantially increase at elevated temperatures. Furthermore, exogenous, precipitated hemicelluloses in pretreated AMH solids resulted in a larger drop in cellulose conversion than the delignified lignocellulosic biomass containing comparably much higher natural hemicellulose amounts. Increased cellulase loadings or supplementation of cellulase with xylanases enhanced cellulose conversion for most pretreated AMH solids; however, this

Recalcitrant vulnerability curves: methods of analysis and the concept of fibre bridges for enhanced cavitation resistance.

PubMed

Cai, Jing; Li, Shan; Zhang, Haixin; Zhang, Shuoxin; Tyree, Melvin T

2014-01-01

Vulnerability curves (VCs) generally can be fitted to the Weibull equation; however, a growing number of VCs appear to be recalcitrant, that is, deviate from a Weibull but seem to fit dual Weibull curves. We hypothesize that dual Weibull curves in Hippophae rhamnoides L. are due to different vessel diameter classes, inter-vessel hydraulic connections or vessels versus fibre tracheids. We used dye staining techniques, hydraulic measurements and quantitative anatomy measurements to test these hypotheses. The fibres contribute 1.3% of the total stem conductivity, which eliminates the hypothesis that fibre tracheids account for the second Weibull curve. Nevertheless, the staining pattern of vessels and fibre tracheids suggested that fibres might function as a hydraulic bridge between adjacent vessels. We also argue that fibre bridges are safer than vessel-to-vessel pits and put forward the concept as a new paradigm. Hence, we tentatively propose that the first Weibull curve may be accounted by vessels connected to each other directly by pit fields, while the second Weibull curve is associated with vessels that are connected almost exclusively by fibre bridges. Further research is needed to test the concept of fibre bridge safety in species that have recalcitrant or normal Weibull curves. © 2013 John Wiley & Sons Ltd.

On the molecular origins of biomass recalcitrance: the interaction network and solvation structures of cellulose microfibrils.

PubMed

Gross, Adam S; Chu, Jhih-Wei

2010-10-28

Biomass recalcitrance is a fundamental bottleneck to producing fuels from renewable sources. To understand its molecular origin, we characterize the interaction network and solvation structures of cellulose microfibrils via all-atom molecular dynamics simulations. The network is divided into three components: intrachain, interchain, and intersheet interactions. Analysis of their spatial dependence and interaction energetics indicate that intersheet interactions are the most robust and strongest component and do not display a noticeable dependence on solvent exposure. Conversely, the strength of surface-exposed intrachain and interchain hydrogen bonds is significantly reduced. Comparing the interaction networks of I(β) and I(α) cellulose also shows that the number of intersheet interactions is a clear descriptor that distinguishes the two allomorphs and is consistent with the observation that I(β) is the more stable form. These results highlight the dominant role of the often-overlooked intersheet interactions in giving rise to biomass recalcitrance. We also analyze the solvation structures around the surfaces of microfibrils and show that the structural and chemical features at cellulose surfaces constrict water molecules into specific density profiles and pair correlation functions. Calculations of water density and compressibility in the hydration shell show noticeable but not drastic differences. Therefore, specific solvation structures are more prominent signatures of different surfaces.

Evaluation of Enhanced Comprehensive 2-D Gas Chromatography-Time-Of-Flight Mass Spectrometry for the Separation of Recalcitrant Polychlorinated Biphenyl Isomers

EPA Science Inventory

The separation of some recalcitrant polychlorinated biphenyl (PCB) isomers in extracts from environmental compartments has been a daunting task for environmental chemists. Summed quantitation values for coeluting PCB isomers are often reported. This composite data obscures the ac...

Pathogenesis of Recalcitrant Chronic Rhinosinusitis: The Emerging Role of Innate Immune Cells.

PubMed

Kong, Il Gyu; Kim, Dae Woo

2018-04-01

Chronic rhinosinusitis (CRS) is a major part of the recalcitrant inflammatory diseases of the upper airway that needs enormous socioeconomic burden. T helper (Th) 2 type immune responses recruiting eosinophils were the most well-known immune players in CRS pathogenesis especially in western countries. By the piling up of a vast amount of researches to elucidate the pathogenic mechanism of CRS recently, heterogeneous inflammatory processes were found to be related to the phenotypes of CRS. Recently more cells other than T cells were in the focus of CRS pathogenesis, such as the epithelial cell, macrophage, innate lymphoid cells, and neutrophils. Here, we reviewed the recent research focusing on the innate immune cells related to CRS pathogenesis.

Pre-dispersal predation effect on seed packaging strategies and seed viability.

PubMed

DeSoto, Lucía; Tutor, David; Torices, Rubén; Rodríguez-Echeverría, Susana; Nabais, Cristina

2016-01-01

An increased understanding of intraspecific seed packaging (i.e. seed size/number strategy) variation across different environments may improve current knowledge of the ecological forces that drive seed evolution in plants. In particular, pre-dispersal seed predation may influence seed packaging strategies, triggering a reduction of the resources allocated to undamaged seeds within the preyed fruits. Assessing plant reactions to pre-dispersal seed predation is crucial to a better understanding of predation effects, but the response of plants to arthropod attacks remains unexplored. We have assessed the effect of cone predation on the size and viability of undamaged seeds in populations of Juniperus thurifera with contrasting seed packaging strategies, namely, North African populations with single-large-seeded cones and South European populations with multi-small-seeded cones. Our results show that the incidence of predation was lower on the single-large-seeded African cones than on the multi-small-seeded European ones. Seeds from non-preyed cones were also larger and had a higher germination success than uneaten seeds from preyed cones, but only in populations with multi-seeded cones and in cones attacked by Trisetacus sp., suggesting a differential plastic response to predation. It is possible that pre-dispersal seed predation has been a strong selective pressure in European populations with high cone predation rates, being a process which maintains multi-small-seeded cones and empty seeds as a strategy to save some seeds from predation. Conversely, pre-dispersal predation might not have a strong effect in the African populations with single-large-seeded cones characterized by seed germination and filling rates higher than those in the European populations. Our results indicate that differences in pre-dispersal seed predators and predation levels may affect both selection on and intraspecific variation in seed packaging.

Labile and recalcitrant organic matter utilization by river biofilm under increasing water temperature.

PubMed

Ylla, Irene; Romaní, Anna M; Sabater, Sergi

2012-10-01

Microbial biofilms in rivers contribute to the decomposition of the available organic matter which typically shows changes in composition and bioavailability due to their origin, seasonality, and watershed characteristics. In the context of global warming, enhanced biofilm organic matter decomposition would be expected but this effect could be specific when either a labile or a recalcitrant organic matter source would be available. A laboratory experiment was performed to mimic the effect of the predicted increase in river water temperature (+4 °C above an ambient temperature) on the microbial biofilm under differential organic matter sources. The biofilm microbial community responded to higher water temperature by increasing bacterial cell number, respiratory activity (electron transport system) and microbial extracellular enzymes (extracellular enzyme activity). At higher temperature, the phenol oxidase enzyme explained a large fraction of respiratory activity variation suggesting an enhanced microbial use of degradation products from humic substances. The decomposition of hemicellulose (β-xylosidase activity) seemed to be also favored by warmer conditions. However, at ambient temperature, the enzymes highly responsible for respiration activity variation were β-glucosidase and leu-aminopeptidase, suggesting an enhanced microbial use of polysaccharides and peptides degradation products. The addition of labile dissolved organic carbon (DOC; dipeptide plus cellobiose) caused a further augmentation of heterotrophic biomass and respiratory activity. The changes in the fluorescence index and the ratio Abs(250)/total DOC indicated that higher temperature accelerated the rates of DOC degradation. The experiment showed that the more bioavailable organic matter was rapidly cycled irrespective of higher temperature while degradation of recalcitrant substances was enhanced by warming. Thus, pulses of carbon at higher water temperature might have consequences for DOC

Seed dispersal and seed fate in Joshua tree (Yucca brevifolia)

USGS Publications Warehouse

Waitman, B.A.; Vander Wall, S.B.; Esque, Todd

2012-01-01

Joshua tree (Yucca brevifolia) is a charismatic symbol of the Mojave Desert. Despite its familiarity, we know little about the reproduction of this species, including mechanisms of seed dispersal. Here we examine mechanisms of seed dispersal and resulting seed fate. We experimentally tracked fruit and seed removal and followed the fates of Joshua tree seeds using radioactive tracers. The majority of Joshua tree fruits monitored were taken directly from the tree canopy by white-tailed antelope squirrels, and seeds and fruits on the soil surface were quickly removed by animals. Rodents given seeds labeled with scandium-46 cached them between 0.1 cm and 4.1 cm deep. Seedling emergence was most common for seeds planted 1 cm deep, whereas seeds placed on the soil surface seldom germinated. Wind dispersal is unlikely because fruits and seeds lack adaptations for wind dispersal; wind speeds required to move Joshua tree seeds and fruits across the soil surface were higher than those typically found in the Mojave Desert. Further, rodents removed most seeds before abiotic burial was possible. We conclude that most Joshua tree seeds are dispersed by scatter hoarding by rodents, and that caches made by rodents are suitable sites for seedling emergence.

A randomized trial of the efficacy of a new micronized formulation versus a standard formulation of isotretinoin in patients with severe recalcitrant nodular acne.

PubMed

Strauss, J S; Leyden, J J; Lucky, A W; Lookingbill, D P; Drake, L A; Hanifin, J M; Lowe, N J; Jones, T M; Stewart, D M; Jarratt, M T; Katz, I; Pariser, D M; Pariser, R J; Tschen, E; Chalker, D K; Rafal, E S; Savin, R P; Roth, H L; Chang, L K; Baginski, D J; Kempers, S; McLane, J; Eberhardt, D; Leach, E E; Bryce, G; Hong, J

2001-08-01

Isotretinoin is very frequently the drug of choice for the management of severe recalcitrant nodular acne. Recently, a new micronized and more bioavailable formulation of isotretinoin has been developed that permits once-daily administration in lower doses than usually used with standard isotretinoin (Accutane), regardless of whether it is taken with or without food. Our purpose was to determine whether micronized isotretinoin and standard isotretinoin are clinically equivalent. In this multicenter, double-blind, double-dummy study, 600 patients with severe recalcitrant nodular acne were treated with either 0.4 mg/kg of micronized isotretinoin once daily without food (n = 300) or 1.0 mg/kg per day of standard isotretinoin in two divided doses with food (n = 300). Lesion counts were monitored over 20 weeks. Both treatment groups in this well-controlled clinical trial experienced an equivalent reduction in the number of total nodules (facial plus truncal). In addition, an equivalent proportion of patients achieved 90% clearance of the total number of nodules. Both formulations had similar results for other efficacy variables. Once-daily use of the micronized and more bioavailable formulation of isotretinoin under fasted conditions is clinically equivalent to the standard twice-daily formulation under fed conditions in the treatment of severe recalcitrant nodular acne.

Seed-feeding insects impacting globemallow seed production

Treesearch

Robert Hammon; Melissa Franklin

2012-01-01

Weevils (Anthonomus sphaeralciae Fall [Coleoptera: Curculionidae]), which attack flowers and developing seeds, can significantly impact globemallow Sphaeralcea spp. A. St.-Hil. (Malvaceae) seed production without a grower even noticing there was insect damage. This weevil damaged almost one-quarter of the flowers in a seed production field in Delta County, Colorado,...

7 CFR 201.18 - Other agricultural seeds (crop seeds).

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Other agricultural seeds (crop seeds). 201.18 Section 201.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling...

7 CFR 201.18 - Other agricultural seeds (crop seeds).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Other agricultural seeds (crop seeds). 201.18 Section 201.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling...

7 CFR 201.18 - Other agricultural seeds (crop seeds).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Other agricultural seeds (crop seeds). 201.18 Section 201.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling...

7 CFR 201.18 - Other agricultural seeds (crop seeds).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Other agricultural seeds (crop seeds). 201.18 Section 201.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling...

7 CFR 201.18 - Other agricultural seeds (crop seeds).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Other agricultural seeds (crop seeds). 201.18 Section 201.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling...

Bioconversion of woody biomass to biofuel and lignin co-product using sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL)

Treesearch

Junyong Zhu; Chao Zhang; Roland Gleisner; Carl Houtman; Xuejun Pan

2016-01-01

Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) promises to provide efficient bioconversion of woody biomass into bioethanol and lignin co-products. Results from several laboratory and pilot-scale studies are presented to demonstrate SPORL performance, with comparisons to competing technologies. Excellent ethanol yields of up to...

Common extensor origin release in recalcitrant lateral epicondylitis - role justified?

PubMed Central

2010-01-01

The aim of our study was to analyse the efficacy of operative management in recalcitrant lateral epicondylitis of elbow. Forty patients included in this study were referred by general practitioners with a diagnosis of tennis elbow to the orthopaedic department at a district general hospital over a five year period. All had two or more steroid injections at the tender spot, without permanent relief of pain. All subsequently underwent simple fasciotomy of the extensor origin. Of forty patients thirty five had improvement in pain and function, two had persistent symptoms and three did not perceive any improvement. Twenty five had excellent, ten had well, two had fair and three had poor outcomes (recurrent problem; pain at rest and night). Two patients underwent revision surgery. Majority of the patients had improvement in pain and function following operative treatment. In this study, an extensor fasciotomy was demonstrated to be an effective treatment for refractory chronic lateral epicondylitis; however, further studies are warranted. PMID:20459701

Seed Coating Increases Seed Moisture Uptake and Restricts Embryonic Oxygen Availability in Germinating Cereal Seeds.

PubMed

Gorim, Linda; Asch, Folkard

2017-05-24

Seed coating is a technology to improve germination and homogenize stand establishment. Although coating often results in lower germination rates, seeds that do germinate grow more vigorously and show strongly reduced respiratory losses during reserve mobilization. We hypothesize that the higher mobilization efficiency is due to a shift in the enzymatic cleavage of sucrose from invertase to sucrose synthase in the embryonic tissue caused by a reduced oxygen availability induced by oversaturation with water caused by the coating during early germination. We investigated the effect of coating on barley, rye, and wheat seed imbibition during the first 30 h after seeds were placed in moisture. We profiled oxygen in the embryos and measured sucrose and acid invertase levels as imbibition progressed. We found that seeds within coatings absorbed significantly more moisture than uncoated seeds. Coating resulted in near anoxic oxygen concentrations in the developing embryonic tissues in all three species. In barley, sucrose was not cleaved via the invertase pathway, despite the fact that invertase activity in coated seeds was increased. In rye and wheat, invertase activities were significantly lower in embryos from coated seeds without significantly changing the sugar composition.

Seed Coating Increases Seed Moisture Uptake and Restricts Embryonic Oxygen Availability in Germinating Cereal Seeds

PubMed Central

Gorim, Linda; Asch, Folkard

2017-01-01

Seed coating is a technology to improve germination and homogenize stand establishment. Although coating often results in lower germination rates, seeds that do germinate grow more vigorously and show strongly reduced respiratory losses during reserve mobilization. We hypothesize that the higher mobilization efficiency is due to a shift in the enzymatic cleavage of sucrose from invertase to sucrose synthase in the embryonic tissue caused by a reduced oxygen availability induced by oversaturation with water caused by the coating during early germination. We investigated the effect of coating on barley, rye, and wheat seed imbibition during the first 30 h after seeds were placed in moisture. We profiled oxygen in the embryos and measured sucrose and acid invertase levels as imbibition progressed. We found that seeds within coatings absorbed significantly more moisture than uncoated seeds. Coating resulted in near anoxic oxygen concentrations in the developing embryonic tissues in all three species. In barley, sucrose was not cleaved via the invertase pathway, despite the fact that invertase activity in coated seeds was increased. In rye and wheat, invertase activities were significantly lower in embryos from coated seeds without significantly changing the sugar composition. PMID:28538658

Non conventional biological treatment based on Trametes versicolor for the elimination of recalcitrant anticancer drugs in hospital wastewater.

PubMed

Ferrando-Climent, Laura; Cruz-Morató, Carles; Marco-Urrea, Ernest; Vicent, Teresa; Sarrà, Montserrat; Rodriguez-Mozaz, Sara; Barceló, Damià

2015-10-01

This work presents a study about the elimination of anticancer drugs, a group of pollutants considered recalcitrant during conventional activated sludge wastewater treatment, using a biological treatment based on the fungus Trametes versicolor. A 10-L fluidized bed bioreactor inoculated with this fungus was set up in order to evaluate the removal of 10 selected anticancer drugs in real hospital wastewater. Almost all the tested anticancer drugs were completely removed from the wastewater at the end of the batch experiment (8 days) with the exception of Ifosfamide and Tamoxifen. These two recalcitrant compounds, together with Cyclophosphamide, were selected for further studies to test their degradability by T. versicolor under optimal growth conditions. Cyclophosphamide and Ifosfamide were inalterable during batch experiments both at high and low concentration, whereas Tamoxifen exhibited a decrease in its concentration along the treatment. Two positional isomers of a hydroxylated form of Tamoxifen were identified during this experiment using a high resolution mass spectrometry based on ultra-high performance chromatography coupled to an Orbitrap detector (LTQ-Velos Orbitrap). Finally the identified transformation products of Tamoxifen were monitored in the bioreactor run with real hospital wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Dynamics of seed rain of Tripterygium hypoglaucum and soil seed bank].

PubMed

Zhang, Zhi-Wei; Wei, Yong-Sheng; Liu, Xiang; Su, Shu; Qu, Xian-You; Wang, Chang-Hua

2017-11-01

Tripterygium hypoglaucum is an endangered species in arid areas of Xiannvshan Chongqing, China. The dynamic characteristics of seed rain and soil seed bank of T. hypoglaucum were studied in this paper．Results showed that T. hypoglaucum years of mature seeds distribution number up to October; the seed rain occurred from the last ten-day of September to in the first ten-day of November and the peak of scattered seed rain concentrated in the October．The numbers of soil seed bank at 2-5 cm soil layer,mainly concentrated in the 1.5-3.5 m range. T. hypoglaucum seeds to the wind as a force for transmission, the transmission ability is strong, but in the process of natural reproduction, full mature seed rate is low, the soil seed bank seeds seed short-lived factors these were unfavorable for the natural reproduction of T. hypoglaucum population. Copyright© by the Chinese Pharmaceutical Association.

[Procedure of seed quality testing and seed grading standard of Prunus humilis].

PubMed

Wen, Hao; Ren, Guang-Xi; Gao, Ya; Luo, Jun; Liu, Chun-Sheng; Li, Wei-Dong

2014-11-01

So far there exists no corresponding quality test procedures and grading standards for the seed of Prunus humilis, which is one of the important source of base of semen pruni. Therefor we set up test procedures that are adapt to characteristics of the P. humilis seed through the study of the test of sampling, seed purity, thousand-grain weight, seed moisture, seed viability and germination percentage. 50 cases of seed specimens of P. humilis tested. The related data were analyzed by cluster analysis. Through this research, the seed quality test procedure was developed, and the seed quality grading standard was formulated. The seed quality of each grade should meet the following requirements: for first grade seeds, germination percentage ≥ 68%, thousand-grain weight 383 g, purity ≥ 93%, seed moisture ≤ 5%; for second grade seeds, germination percentage ≥ 26%, thousand-grain weight ≥ 266 g, purity ≥ 73%, seed moisture ≤9%; for third grade seeds, germination percentage ≥ 10%, purity ≥ 50%, thousand-grain weight ≥ 08 g, seed moisture ≤ 13%.

Effect of Seed Density on Splash Cup Seed Dispersal

NASA Astrophysics Data System (ADS)

Wigger, Patrick; Pepper, Rachel

2017-11-01

Splash cup plants are plants that utilize a small, mm-sized cup filled with seeds as a method of seed dispersal. The cup uses kinetic energy of an incident raindrop in order to project the seeds away from the plant up to 1 meter. The dispersal distance is important to ensure the offspring are not clustered too tightly to the parent plant. It has previously been found that a cup angle of 40 degrees to the horizontal is optimal for maximum dispersal of water from cups with no seeds. In this study we examine if the 40 degree cup is optimal for cups containing seeds with varying densities. We released uniform water drops above 5.0 mm 3D printed models of splash cups, using 1.0 mm plastic and glass microspheres of varying densities to simulate seeds. We observed the dispersal characteristics of each bead type by measuring the final seed locations after each splash, and by recording high speed video to determine the angle and velocity of the seeds as they exited the cup.

Electrochemotherapy treatment of a recalcitrant earlobe keloid scar with chronic lymphocytic leukaemia infiltration.

PubMed

Sainsbury, D C G; Allison, K P; Muir, T

2010-10-01

Electrochemotherapy, a tumour ablation modality, which facilitates intracellular delivery of poorly-permeable cytotoxic drugs, such as bleomycin, has shown promising results in the treatment of cutaneous and subcutaneous melanomatous and non-melanomatous metastases. We report the case of a 52-year-old Caucasian gentleman with a keloid scar to his left earlobe that developed following a piercing. Despite multiple intralesional steroidal injections, five intralesional excisions and a course of superficial radiotherapy the keloid scar remained over nine years later. For 15 years the patient had also suffered chronic lymphocytic leukaemia with no nodal disease or systemic involvement. However, histological analysis of the final surgical excision specimen showed chronic lymphocytic leukaemia infiltration of the keloid scar. Further surgical excision seemed unwise considering the recalcitrance of the keloid scar. Additionally, no systemic chemotherapy treatment options were feasible. Electrochemotherapy was performed under local anaesthesia with the aim of eradicating the chronic lymphocytic leukaemia deposit within the keloid lesion. Four sessions of electrochemotherapy using bleomycin were deployed over 11 months. A deep core biopsy of the treated keloid performed three months following the last electrochemotherapy session showed no evidence of chronic lymphocytic leukaemia. Serendipitously, following the initial electrochemotherapy treatment no further growth of the keloid scar was observed. Furthermore, subsequent electrochemotherapy led to a substantial reduction in size of the keloid sustained for 14 months at last follow-up. This report highlights the exciting potential of electrochemotherapy and bleomycin in the treatment of recalcitrant scars. Larger, well-designed clinical and in-vitro studies are required to further elucidate the exact role, mechanism and cost-effectiveness of electrochemotherapy in this area. Copyright 2010 British Association of Plastic

Joshua tree (Yucca brevifolia) seeds are dispersed by seed-caching rodents

USGS Publications Warehouse

Vander Wall, S.B.; Esque, T.; Haines, D.; Garnett, M.; Waitman, B.A.

2006-01-01

Joshua tree (Yucca brevifolia) is a distinctive and charismatic plant of the Mojave Desert. Although floral biology and seed production of Joshua tree and other yuccas are well understood, the fate of Joshua tree seeds has never been studied. We tested the hypothesis that Joshua tree seeds are dispersed by seed-caching rodents. We radioactively labelled Joshua tree seeds and followed their fates at five source plants in Potosi Wash, Clark County, Nevada, USA. Rodents made a mean of 30.6 caches, usually within 30 m of the base of source plants. Caches contained a mean of 5.2 seeds buried 3-30 nun deep. A variety of rodent species appears to have prepared the caches. Three of the 836 Joshua tree seeds (0.4%) cached germinated the following spring. Seed germination using rodent exclosures was nearly 15%. More than 82% of seeds in open plots were removed by granivores, and neither microsite nor supplemental water significantly affected germination. Joshua tree produces seeds in indehiscent pods or capsules, which rodents dismantle to harvest seeds. Because there is no other known means of seed dispersal, it is possible that the Joshua tree-rodent seed dispersal interaction is an obligate mutualism for the plant.

Revisiting the concept of recalcitrance and organic matter persistence in soils and aquatic systems: Does environment trump chemistry?

NASA Astrophysics Data System (ADS)

Marin-Spiotta, E.

2014-12-01

Most ecological models of decomposition rely on plant litter chemistry. However, growing evidence suggests that the chemical composition of organic matter (OM) is not a good predictor of its eventual fate in terrestrial or aquatic environments. New data on variable decomposition rates of select organic compounds challenge concepts of chemical recalcitrance, i.e. the inherent ability of certain molecular structures to resist biodegradation. The role of environmental or "ecosystem" properties on influencing decomposition dates back to some of the earliest research on soil OM. Despite early recognition that the physical and aqueous matrices are critical in determining the fate of organic compounds, the prevailing paradigm hinges on intrinsic chemical properties as principal predictors of decay rate. Here I build upon recent reviews and discuss new findings that contribute to three major transformations in our understanding of OM persistence: (1) a shift away from an emphasis on chemical recalcitrance as a primary predictor of turnover, (2) new interpretations of radiocarbon ages which challenge predictions of reactivity, and (3) the recognition that most detrital OM accumulating in soils and in water has been microbially processed. Predictions of OM persistence due to aromaticity are challenged by high variability in lignin and black C turnover observed in terrestrial and aquatic environments. Contradictions in the behavior of lignin are, in part, influenced by inconsistent methodologies among research communities. Even black C, long considered to be one of the most recalcitrant components of OM, is susceptible to biodegradation, challenging predictions of the stability of aromatic structures. At the same time, revised interpretations of radiocarbon data suggest that organic compounds can acquire long mean residence times by various mechanisms independent of their molecular structure. Understanding interactions between environmental conditions and biological

Direct seeding

Treesearch

Richard M. Godman; G. A. Mattson

1992-01-01

At present, direct seeding of hardwoods in the Lake States is more of a supplemental than a primary means of artificial regeneration. Direct seeding may be used to augment a poor seed crop or increase the proportion of a preferred species. In the future, it will no doubt play a bigger role-in anticipation of this we need to collect and store the amounts of seed needed...

Seed rain, soil seed bank, seed loss and regeneration of Castanopsis fargesii (Fagaceae) in a subtropical evergreen broad-leaved forest

USGS Publications Warehouse

Du, X.; Guo, Q.; Gao, X.; Ma, K.

2007-01-01

Understanding the seed rain and seed loss dynamics in the natural condition has important significance for revealing the natural regeneration mechanisms. We conducted a 3-year field observation on seed rain, seed loss and natural regeneration of Castanopsis fargesii Franch., a dominant tree species in evergreen broad-leaved forests in Dujiangyan, southwestern China. The results showed that: (1) there were marked differences in (mature) seed production between mast (733,700 seeds in 2001) and regular (51,200 and 195,600 seeds in 2002 and 2003, respectively) years for C. fargesii. (2) Most seeds were dispersed in leaf litter, humus and 0-2 cm depth soil in seed bank. (3) Frequency distributions of both DBH and height indicated that C. fargesii had a relatively stable population. (4) Seed rain, seed ground density, seed loss, and leaf fall were highly dynamic and certain quantity of seeds were preserved on the ground for a prolonged time due to predator satiation in both the mast and regular years so that the continuous presence of seed bank and seedling recruitments in situ became possible. Both longer time observations and manipulative experiments should be carried out to better understand the roles of seed dispersal and regeneration process in the ecosystem performance. ?? 2006 Elsevier B.V. All rights reserved.

Platelet-rich plasma versus corticosteroid injection for recalcitrant lateral epicondylitis: clinical and ultrasonographic evaluation.

PubMed

Gautam, V K; Verma, Saurabh; Batra, Sahil; Bhatnagar, Nidhi; Arora, Sumit

2015-04-01

To evaluate the clinical and ultrasonographic changes in the morphology and vascularity of the common extensor tendon after injecting platelet-rich plasma (PRP) or corticosteroid (CS) for recalcitrant lateral epicondylitis (LE). 30 patients aged 18 to 60 years with recalcitrant (>6 months) LE not responsive to oral medication or non-invasive treatment were randomised to receive PRP (n=15) or CS (n=15) injection. Patients were assessed using the visual analogue scale (VAS) for pain, Disabilities of the Arm, Shoulder and Hand Scale (DASH) score, Oxford Elbow Score, modified Mayo Clinic performance index for the elbow (modified Mayo score), and hand grip strength. Ultrasonography was performed by a musculoskeletal ultrasonologist to evaluate for tear at the common extensor origin, oedema at the common extensor origin, cortical erosion, probe-induced tenderness, and thickness of the tendon. The VAS for pain, DASH score, Oxford Elbow Score, modified Mayo score, and hand grip strength all improved significantly from pre-injection to the 6-month follow-up in the PRP and CS groups. However, in the CS group, the scores generally peaked at 3 months and then deteriorated slightly at 6 months indicating recurrence of symptoms, which involved 46.7% of the CS patients. At 6 months, the number of patients positive for various ulrasonographic findings generally decreased. However, in the CS group, the number of patients with reduced thickness of the common extensor tendon increased from 2 to 12, and the number of patients with cortical erosion at the lateral epicondyle increased from 9 to 11. PRP appeared to enable biological healing of the lesion, whereas CS appeared to provide short-term, symptomatic relief but resulted in tendon degeneration.

The key role of biogenic manganese oxides in enhanced removal of highly recalcitrant 1,2,4-triazole from bio-treated chemical industrial wastewater.

PubMed

Wu, Ruiqin; Wu, Haobo; Jiang, Xinbai; Shen, Jinyou; Faheem, Muhammad; Sun, Xiuyun; Li, Jiansheng; Han, Weiqing; Wang, Lianjun; Liu, Xiaodong

2017-04-01

The secondary effluent from biological treatment process in chemical industrial plant often contains refractory organic matter, which deserves to be further treated in order to meet the increasingly stringent environmental regulations. In this study, the key role of biogenic manganese oxides (BioMnOx) in enhanced removal of highly recalcitrant 1,2,4-triazole from bio-treated chemical industrial wastewater was investigated. BioMnOx production by acclimated manganese-oxidizing bacterium (MOB) consortium was confirmed through scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis. Pseudomonas and Bacillus were found to be the most predominant species in acclimated MOB consortium. Mn 2+ could be oxidized optimally at neutral pH and initial Mn 2+ concentration below 33 mg L -1 . However, 1,2,4-triazole removal by BioMnOx produced occurred optimally at slightly acidic pH. High dosage of both Mn 2+ and 1,2,4-triazole resulted in decreased 1,2,4-triazole removal. In a biological aerated filter (BAF) coupled with manganese oxidation, 1,2,4-triazole and total organic carbon removal could be significantly enhanced compared to the control system without the participation of manganese oxidation, confirming the key role of BioMnOx in the removal of highly recalcitrant 1,2,4-triazole. This study demonstrated that the biosystem coupled with manganese oxidation had a potential for the removal of various recalcitrant contaminants from bio-treated chemical industrial wastewater.

Chemical, ultrastructural and supramolecular analysis of tension wood in Populus tremula x alba as a model substrate for reduced recalcitrance

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

Foston, Marcus B; Hubbell, Christopher A; Samuel, Reichel

2011-01-01

Biomass is one of the most abundant potential sustainable sources for fuel and material production, however to fully realize this potential an improved understanding of lignocellulosic recalcitrance must be developed. In an effort to appreciate the underlying phenotypic, biochemical and morphological properties associated with the reduced recalcitrance observed in tension stress-induced reaction wood, we report the increased enzymatic sugar yield and corresponding chemical and ultrastructural properties of Populus tension wood. Populus tremula x alba (PTA) was grown under tension and stem segments containing three different wood types: normal wood (NW), tension wood (TW) from the elongated stem side and oppositemore » wood (OW) from the compressed stem side were collected. A variety of analytical techniques were used to describe changes occurring as a result of the tension stress-induced formation of a gelatinous cell wall layer (G-layer). For example, gel permeation chromatography (GPC) and 13C solid-state nuclear magnetic resonance (NMR) revealed that the molecular weight and crystallinity of cellulose in TW is greater than that of cellulose acquired from NW. Whole cell ionic liquid and other solid-state NMR analysis detailed the structure of lignin and hemicellulose in the samples, detecting the presence of variations in lignin and hemicellulose sub-units, linkages and semi-quantitatively estimating the relative amounts of syringyl (S), guaiacyl (G) and p-hydroxybenzoate (PB) monolignol units. It was confirmed that TW displayed an increase in PB or H-like lignin and S to G ratio from 1.25 to 1.50 when compared to the NW sample. Scanning electron microscopy (SEM) and coherent anti-Stokes Raman scattering (CARS) were also used to evaluate the morphology and corresponding spatial distribution of the major lignocellulosic components. We found changes in a combination of cell wall properties appear to influence recalcitrance more than any single factor alone.« less

Emancipating Chlamydia: Advances in the Genetic Manipulation of a Recalcitrant Intracellular Pathogen

PubMed Central

Bastidas, Robert J.

2016-01-01

SUMMARY Chlamydia species infect millions of individuals worldwide and are important etiological agents of sexually transmitted disease, infertility, and blinding trachoma. Historically, the genetic intractability of this intracellular pathogen has hindered the molecular dissection of virulence factors contributing to its pathogenesis. The obligate intracellular life cycle of Chlamydia and restrictions on the use of antibiotics as selectable markers have impeded the development of molecular tools to genetically manipulate these pathogens. However, recent developments in the field have resulted in significant gains in our ability to alter the genome of Chlamydia, which will expedite the elucidation of virulence mechanisms. In this review, we discuss the challenges affecting the development of molecular genetic tools for Chlamydia and the work that laid the foundation for recent advancements in the genetic analysis of this recalcitrant pathogen. PMID:27030552

Seed predators exert selection on the subindividual variation of seed size.

PubMed

Sobral, M; Guitián, J; Guitián, P; Larrinaga, A R

2014-07-01

Subindividual variation among repeated organs in plants constitutes an overlooked level of variation in phenotypic selection studies, despite being a major component of phenotypic variation. Animals that interact with plants could be selective agents on subindividual variation. This study examines selective pressures exerted during post-dispersal seed predation and germination on the subindividual variation of seed size in hawthorn (Crataegus monogyna). With a seed offering experiment and a germination test, we estimated phenotypic selection differentials for average and subindividual variation of seed size due to seed predation and germination. Seed size affects germination, growth rate and the probability of an individual seed of escaping predation. Longer seeds showed higher germination rates, but this did not result in significant selection on phenotypes of the maternal trees. On the other hand, seed predators avoided wider seeds, and by doing so exerted phenotypic selection on adult average and subindividual variation of seed size. The detected selection on subindividual variation suggests that the levels of phenotypic variation within individual plants may be, at least partly, the adaptive consequence of animal-mediated selection. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Producing the target seed: Seed collection, treatment, and storage

Treesearch

Robert P. Karrfalt

2011-01-01

The role of high quality seeds in producing target seedlings is reviewed. Basic seed handling and upgrading techniques are summarized. Current advances in seed science and technology as well as those on the horizon are discussed.

Converting standard seeding rates for grasses to actual seeding rates per acre.

Treesearch

Joseph F. Pechanec

1950-01-01

Standard rates specifying the amount of grass seed to sow per acre are stated in most of the more recent publications as pounds of live pure seed (lps) to be used. For a seeding project these rates must be converted to the actual amount of seed to sow because seed as purchased from the dealer or grower is never all live pure seed. Even the best lots of seed contain...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

Consistent individual differences in seed disperser quality in a seed-eating fish.

PubMed

Pollux, Bart J A

2017-01-01

Animal-mediated seed dispersal (zoochory) is considered to be an important mechanism regulating biological processes at larger spatial scales. To date, intra-specific variation in seed disperser quality within seed-dispersing animals has not been studied. Here, I employed seed feeding trials to quantify individual differences in disperser quality within the common carp (Cyprinus carpio) using seeds of two aquatic plants: unbranched bur-reed (Sparganium emersum, Sparganiaceae) and arrowhead (Sagittaria sagittifolia, Alismataceae). I found substantial variation among carp individuals in their propensity to ingest seeds and their ability to digest them, resulting in up to 31-fold differences in the probability of seed dispersal. In addition, there were significant differences in the time that seeds are retained in their digestive systems, generating a twofold difference in the maximum distance over which they can potentially disperse seeds. I propose that seed-eating animal species consist of individuals that display continuous variation in disperser quality, with at one end of the continuum individuals that are likely to eat seeds, pass them unharmed through their digestive tract and transport them over large distances to new locations (i.e. high-quality seed dispersers) and at the other end individuals that rarely eat seeds, destroy most of the ones they ingest and transport the few surviving seeds over relatively short distances (low-quality seed dispersers). Although individual differences in seed dispersal quality could be the result of a variety of factors, these results underline the ecological and evolutionary potential of such variation for both plants and animals.

Early experience and results of bone graft enriched with autologous platelet gel for recalcitrant nonunions of lower extremity.

PubMed

Chiang, Chao-Ching; Su, Chen-Yao; Huang, Ching-Kuei; Chen, Wei-Ming; Chen, Tain-Hsiung; Tzeng, Yun-Hsuan

2007-09-01

Refractory nonunions of the tibia or femur are physically and mentally devastating conditions for the patients, and the treatment is challenging for orthopedic surgeons. The goal of this study was to assess the feasibility and outcome of surgical treatment in recalcitrant nonunions of a lower extremity with bone graft enriched with autologous platelet gel (APG). Twelve patients with four femoral and eight tibial atrophic nonunions after multiple prior procedures were included. All of them were treated with the bone grafting procedures with autograft complex enriched with APG. They were evaluated with radiographs, bone mineral density for bony healing process, and the Short-Form 36 Health Survey for functional outcome. Of the 12 patients, 11 healed at an average of 19.7 weeks after the first attempt and 1 healed after the second attempt at 21 weeks. The bone mineral density continued to increase steadily from early healing to the remodeling phase. Functional status was greatly improved at an average follow-up of 32.4 months. The results of this preliminary study implied the possible potential of bone graft enriched with APG in the treatment of recalcitrant nonunions of the lower extremity. More research is necessary to clarify its role in augmentation of bone graft to enhance healing of nonunion.

Effects of rodent species, seed species, and predator cues on seed fate

NASA Astrophysics Data System (ADS)

Sivy, Kelly J.; Ostoja, Steven M.; Schupp, Eugene W.; Durham, Susan

2011-07-01

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord's kangaroo rat ( Dipodomys ordii) and the Great Basin pocket mouse ( Perognathus parvus). The indirect cue was shrub cover, a feature of the environment. Direct cues, presented individually, were (1) control, (2) coyote ( Canis latrans) vocalization, (3) coyote scent, (4) red fox ( Vulpes vulpes) scent, or (5) short-eared owl ( Asio flammeus) vocalization. We offered seeds of three sizes: two native grasses, Indian ricegrass ( Achnatherum hymenoides) and bluebunch wheatgrass ( Pseudoroegneria spicata), and the non-native cereal rye ( Secale cereale), each in separate trays. Kangaroo rats preferentially harvested Indian ricegrass while pocket mice predominately harvested Indian ricegrass and cereal rye. Pocket mice were more likely to scatter hoard preferred seeds, whereas kangaroo rats mostly consumed and/or larder hoarded preferred seeds. No predator cue significantly affected seed preferences. However, both species altered seed handling behavior in response to direct predation cues by leaving more seeds available in the seed pool, though they responded to different predator cues. If these results translate to natural dynamics on the landscape, the two rodents are expected to have different impacts on seed survival and plant recruitment via their different seed selection and seed handling behaviors.

Effects of rodent species, seed species, and predator cues on seed fate

USGS Publications Warehouse

Sivy, Kelly J.; Ostoja, Steven M.; Schupp, Eugene W.; Durham, Susan

2011-01-01

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord's kangaroo rat (Dipodomys ordii) and the Great Basin pocket mouse (Perognathus parvus). The indirect cue was shrub cover, a feature of the environment. Direct cues, presented individually, were (1) control, (2) coyote (Canis latrans) vocalization, (3) coyote scent, (4) red fox (Vulpes vulpes) scent, or (5) short-eared owl (Asio flammeus) vocalization. We offered seeds of three sizes: two native grasses, Indian ricegrass (Achnatherum hymenoides) and bluebunch wheatgrass (Pseudoroegneria spicata), and the non-native cereal rye (Secale cereale), each in separate trays. Kangaroo rats preferentially harvested Indian ricegrass while pocket mice predominately harvested Indian ricegrass and cereal rye. Pocket mice were more likely to scatter hoard preferred seeds, whereas kangaroo rats mostly consumed and/or larder hoarded preferred seeds. No predator cue significantly affected seed preferences. However, both species altered seed handling behavior in response to direct predation cues by leaving more seeds available in the seed pool, though they responded to different predator cues. If these results translate to natural dynamics on the landscape, the two rodents are expected to have different impacts on seed survival and plant recruitment via their different seed selection and seed handling behaviors.

Timing of seed dispersal generates a bimodal seed bank depth distribution

USGS Publications Warehouse

Espinar, J.L.; Thompson, K.; Garcia, L.V.

2005-01-01

The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is possible that some seeds fall down cracks and rapidly become deeply buried. We investigated this possibility for three dominant clonal perennials (Scirpus maritimus, S. litoralis, and Juncus subulatus) in the Don??ana salt marsh, a nontidal marsh with a Mediterranean climate located in southwest Spain. Two species, which shed most of their seed during the dry season and have seeds with low buoyancy, had bimodal viable seed depth distributions, with peak densities at the surface and at 16-20 cm. A third species, which shed most seeds after soil cracks had closed and had seeds with high buoyancy, had viable seeds only in surface soil. Bimodal seed bank depth distributions may be relatively common in seasonally dry habitats with fine-textured soils, but their ecological significance has not been investigated.

[Study on procedure of seed quality testing and seed grading scale of Phellodendron amurense].

PubMed

Liu, Yanlu; Zhang, Zhao; Dai, Lingchao; Zhang, Bengang; Zhang, Xiaoling; Wang, Han

2011-12-01

To study the procedure of seed quality testing and seed grading scale of Phellodendron amurense. Seed quality testing methods were developed, which included the test of sampling, seed purity, weight per 1 000 seeds, seed moisture, seed viability and germination rate. The related data from 62 cases of seed specimens of P. amurense were analyzed by cluster analysis. The seed quality test procedure was developed, and the seed quality grading scale was formulated.

Anaerobic co-digestion of recalcitrant agricultural wastes: Characterizing of biochemical parameters of digestate and its impacts on soil ecosystem.

PubMed

Muscolo, Adele; Settineri, Giovanna; Papalia, Teresa; Attinà, Emilio; Basile, Carmelo; Panuccio, Maria Rosaria

2017-05-15

Anaerobic digestion (AD) of organic wastes is a promising alternative to landfilling for reducing Greenhouse Gas Emission (GHG) and it is encouraged by current regulation in Europe. Biogas-AD produced, represents a useful source of green energy, while its by-product (digestate) is a waste, that needs to be safely disposal. The sustainability of anaerobic digestion plants partly depends on the management of their digestion residues. This study has been focused on the environmental and economic benefits of co-digest recalcitrant agricultural wastes such olive wastes and citrus pulp, in combination with livestock wastes, straw and cheese whey for biogas production. The aim of this work was to investigate the effects of two different bioenergy by-products on soil carbon stock, enzymes involved in nutrient cycling and microbial content. The two digestates were obtained from two plants differently fed: the first plant (Uliva) was powered with 60% of recalcitrant agricultural wastes, and 40% of livestock manure milk serum and maize silage. The second one (Fattoria) was fed with 40% of recalcitrant agricultural wastes and 60% of livestock manure, milk serum and maize silage. Each digestate, separated in liquid and solid fractions, was added to the soil at different concentrations. Our results evidenced that mixing and type of input feedstock affected the composition of digestates. Three months after treatments, our results showed that changes in soil chemical and biochemical characteristics depended on the source of digestate, the type of fraction and the concentration used. The mainly affected soil parameters were: Soil Organic Matter (SOM), Microbial Biomass Carbon (MBC), Fluorescein Diacetate Hydrolysis (FDA), Water Soluble Phenol (WSP) and Catalase (CAT) that can be used to assess the digestate agronomical feasibility. These results show that the agronomic quality of a digestate is strictly dependent on percentage and type of feedstocks that will be used to power the

Calcium maelstrom: recalcitrant hypocalcaemia following rapid correction of thyrotoxicosis, exacerbated by pregnancy

PubMed Central

Shin, Terry; Guerrero, Arthur F

2015-01-01

A 29-year-old pregnant woman with Graves’ disease presented with severe persistent hypocalcaemia after thyroidectomy. Six months prior to presentation she was diagnosed with Graves’ disease and remained uncontrolled with methimazole. She was confirmed pregnant prior to radioactive iodine ablation (RAI), and underwent total thyroidectomy during her second trimester. After surgery, continuous intravenous calcium infusion was required until delivery of the fetus allowed discontinuation at postoperative day 18, despite oral calcium and calcitriol administration. A total of 38 g of oral and 7.5 g of intravenous elemental calcium was administered. We report an unusual case of recalcitrant hypocalcaemia thought to be due to a combination of postoperative hypoparathyroidism, combined with thyrotoxic osteodystrophy and pregnancy, after surgical correction of Graves’ disease. Increased vigilance and early calcium supplementation should be a priority in the management of these patients. PMID:25969482

Emancipating Chlamydia: Advances in the Genetic Manipulation of a Recalcitrant Intracellular Pathogen.

PubMed

Bastidas, Robert J; Valdivia, Raphael H

2016-06-01

Chlamydia species infect millions of individuals worldwide and are important etiological agents of sexually transmitted disease, infertility, and blinding trachoma. Historically, the genetic intractability of this intracellular pathogen has hindered the molecular dissection of virulence factors contributing to its pathogenesis. The obligate intracellular life cycle of Chlamydia and restrictions on the use of antibiotics as selectable markers have impeded the development of molecular tools to genetically manipulate these pathogens. However, recent developments in the field have resulted in significant gains in our ability to alter the genome of Chlamydia, which will expedite the elucidation of virulence mechanisms. In this review, we discuss the challenges affecting the development of molecular genetic tools for Chlamydia and the work that laid the foundation for recent advancements in the genetic analysis of this recalcitrant pathogen. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Recalcitrant Epithelial Ingrowth After SMILE Treated With a Hydrogel Ocular Sealant.

PubMed

Thulasi, Praneetha; Kim, Sang Woo; Shetty, Rohit; Randleman, J Bradley

2015-12-01

To report a case of recalcitrant epithelial ingrowth after small incision lenticule extraction (SMILE) treated successfully with a novel hydrogel ocular sealant. Case report and literature review. A 32-year-old man who underwent small incision lenticule extraction (SMILE) complicated by difficult lenticule extraction developed visually significant epithelial ingrowth. He then underwent two flap lifts and epithelial scrapings and flap edge suturing with recurrence of epithelial ingrowth despite these interventions. He subsequently underwent repeat scraping, followed by hydrogel ocular sealant placement (ReSure Sealant; Ocular Therapeutix, Inc., Bedford, MA), which prevented recurrence of epithelial ingrowth and reduced corneal haze. The patient was also found to have undiagnosed diabetes, suggesting that just as in LASIK, diabetes may be a risk factor for epithelial ingrowth after SMILE. Interface epithelial ingrowth is a potential complication after SMILE and diabetes may be a risk factor for this complication. Hydrogel ocular sealant may be effective after SMILE to prevent epithelial ingrowth into the interface. Copyright 2015, SLACK Incorporated.

Myrmecochory and short-term seed fate in Rhamnus alaternus: Ant species and seed characteristics

NASA Astrophysics Data System (ADS)

Bas, J. M.; Oliveras, J.; Gómez, C.

2009-05-01

Benefits conferred on plants in ant-mediated seed dispersal mutualisms (myrmecochory) depend on the fate of transported seeds. We studied the effects of elaiosome presence, seed size and seed treatment (with and without passage through a bird's digestive tract) on short-term seed fate in Rhamnus alaternus. In our study, we define short-term seed, or initial, seed fate, as the location where ants release the seeds after ant contact with it. The elaiosomes had the most influence on short-term fate, i.e. whether or not seeds were transported to the nest. The workers usually transported big seeds more often than small ones, but small ants did not transport large seeds. Effect of seed size on transport depended on the ant species and on the treatment of the seed (manual extraction simulating a direct fall from the parent plant vs. bird deposition corresponding to preliminary primary dispersal). Probability of removal of elaiosome-bearing seeds to the nest by Aphaenogaster senilis increased with increasing seed weight.

New design of experiment combined with UV-Vis spectroscopy for extraction and estimation of polyphenols from Basil seeds, Red seeds, Sesame seeds and Ajwan seeds

NASA Astrophysics Data System (ADS)

Mabood, Fazal; Gilani, Syed Abdullah; Hussain, Javid; Alshidani, Sulaiman; Alghawi, Said; Albroumi, Mohammed; Alameri, Saif; Jabeen, Farah; Hussain, Zahid; Al-Harrasi, Ahmed; Al Abri, Zahra K. M.; Farooq, Saima; Naureen, Zakira; Hamaed, Ahmad; Rasul Jan, M.; Shah, Jasmin

2017-05-01

New experimental designs for the extraction of polyphenols from different seeds including Basil seed, Red seed, Sesame seeds and Ajwan seeds were investigated. Four variables the concentration and volume of methanol and NaOH solutions as well as the temperature and time of extraction were varied to see their effect on total phenol extraction. The temperature was varied in the range from 25 °C to 200 °C while the time in the range from 30 to 200 minutes. Response surface methodology was used to optimize the extraction parameters. The estimation of polyphenols was measured through phenols reduction UV-Vis spectroscopic method of phosphotungstic-phosphomolybdic acids (Folin-Ciocalteu's reagent). Calibration curve was made by using tannic acid as a polyphenols standard in the concentration range from 0.1 to 10 ppm. The regression line obtained shows the value of correlation coefficient i.e. R = 0.930 and Root mean square error of cross validation (RMSEC) value of 0.0654. The Basil seeds were found containing the highest amount of total phenols i.e. 785.76 mg/100 g. While the Sesame seeds having the least amount i.e. 33.08 mg/100 g. The Ajwan seeds and the Red seeds are containing the medium amounts i.e. 379 mg/100 g and 220.54 mg/100 g respectively.

New design of experiment combined with UV-Vis spectroscopy for extraction and estimation of polyphenols from Basil seeds, Red seeds, Sesame seeds and Ajwan seeds.

PubMed

Mabood, Fazal; Gilani, Syed Abdullah; Hussain, Javid; Alshidani, Sulaiman; Alghawi, Said; Albroumi, Mohammed; Alameri, Saif; Jabeen, Farah; Hussain, Zahid; Al-Harrasi, Ahmed; Al Abri, Zahra K M; Farooq, Saima; Naureen, Zakira; Hamaed, Ahmad; Rasul Jan, M; Shah, Jasmin

2017-05-05

New experimental designs for the extraction of polyphenols from different seeds including Basil seed, Red seed, Sesame seeds and Ajwan seeds were investigated. Four variables the concentration and volume of methanol and NaOH solutions as well as the temperature and time of extraction were varied to see their effect on total phenol extraction. The temperature was varied in the range from 25°C to 200°C while the time in the range from 30 to 200minutes. Response surface methodology was used to optimize the extraction parameters. The estimation of polyphenols was measured through phenols reduction UV-Vis spectroscopic method of phosphotungstic-phosphomolybdic acids (Folin-Ciocalteu's reagent). Calibration curve was made by using tannic acid as a polyphenols standard in the concentration range from 0.1 to 10ppm. The regression line obtained shows the value of correlation coefficient i.e. R=0.930 and Root mean square error of cross validation (RMSEC) value of 0.0654. The Basil seeds were found containing the highest amount of total phenols i.e. 785.76mg/100g. While the Sesame seeds having the least amount i.e. 33.08mg/100g. The Ajwan seeds and the Red seeds are containing the medium amounts i.e. 379mg/100g and 220.54mg/100g respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Seed proteomics.

PubMed

Miernyk, Ján A; Hajduch, Martin

2011-04-01

Seeds comprise a protective covering, a small embryonic plant, and a nutrient-storage organ. Seeds are protein-rich, and have been the subject of many mass spectrometry-based analyses. Seed storage proteins (SSP), which are transient depots for reduced nitrogen, have been studied for decades by cell biologists, and many of the complicated aspects of their processing, assembly, and compartmentation are now well understood. Unfortunately, the abundance and complexity of the SSP requires that they be avoided or removed prior to gel-based analysis of non-SSP. While much of the extant data from MS-based proteomic analysis of seeds is descriptive, it has nevertheless provided a preliminary metabolic picture explaining much of their biology. Contemporary studies are moving more toward analysis of protein interactions and posttranslational modifications, and functions of metabolic networks. Many aspects of the biology of seeds make then an attractive platform for heterologous protein expression. Herein we present a broad review of the results from the proteomic studies of seeds, and speculate on a potential future research directions. Copyright © 2010 Elsevier B.V. All rights reserved.

The effectiveness of topical colloidal silver in recalcitrant chronic rhinosinusitis: a randomized crossover control trial.

PubMed

Scott, John R; Krishnan, Rohin; Rotenberg, Brian W; Sowerby, Leigh J

2017-11-25

Recalcitrant chronic rhinosinusitis without polyposis (CRSsP) is a challenging condition to manage as traditional medical therapies and surgery fail to provide satisfactory clinical improvements. Colloidal silver (CS), a widely used naturopathic agent, has recently shown anti-biofilm properties both in vitro and within a rhinosinusitis animal model. To date, no trials involving humans have been published in world literature. The purpose of this study was to assess the efficacy of CS as a topical nasal spray in patients with refractory CRSsP. A prospective cohort study was conducted using a convenience sample of 20 randomized patients with crossover methodology, comparing nasal sprays with CS versus saline. Patients sprayed twice daily for six weeks with the first intervention and then switched to the second for the next six weeks, with measurements made at baseline and each time point. Primary outcomes were changes in SNOT-22 and Lund-Kennedy (LK) endoscopic scores. All analysis was non-parametric and was conducted using STATA 14. Twenty-two patients were enrolled in the study with 20 completing the entire protocol. Mean 6-week change in SNOT-22 scores were -2.8 and 1.0 for saline and CS, respectively (p = 0.373). Similarly, mean 6-week change in LK scores were -1.4 and -1.1 for saline and CS, respectively (p = 0.794). Significant period effects were observed with the SNOT-22 score between the randomized groups. No participants experienced negative health effects directly attributable to the administration of intranasal CS. Commercially available CS nasal spray did not demonstrate any meaningful subjective or objective improvements in patients with recalcitrant CRSsP. NCT02403479 . Registered on March 1, 2015.

Towards a better monitoring of seed ageing under ex situ seed conservation

PubMed Central

Fu, Yong-Bi; Ahmed, Zaheer; Diederichsen, Axel

2015-01-01

Long-term conservation of 7.4 million ex situ seed accessions held in agricultural genebanks and botanic gardens worldwide is a challenging mission for human food security and ecosystem services. Recent advances in seed biology and genomics may have opened new opportunities for effective management of seed germplasm under long-term storage. Here, we review the current development of tools for assessing seed ageing and research advances in seed biology and genomics, with a focus on exploring their potential as better tools for monitoring of seed ageing. Seed ageing is found to be associated with the changes reflected in reactive oxygen species and mitochondria-triggered programmed cell deaths, expression of antioxidative genes and DNA and protein repair genes, chromosome telomere lengths, epigenetic regulation of related genes (microRNA and methylation) and altered organelle and nuclear genomes. Among these changes, the signals from mitochondrial and nuclear genomes may show the most promise for use in the development of tools to predict seed ageing. Non-destructive and non-invasive analyses of stored seeds through calorimetry or imaging techniques are also promising. It is clear that research into developing advanced tools for monitoring seed ageing to supplement traditional germination tests will be fruitful for effective conservation of ex situ seed germplasm. PMID:27293711

Seed Treatment. Manual 92.

ERIC Educational Resources Information Center

Missouri Univ., Columbia. Agricultural Experiment Station.

This training manual provides information needed to meet minimum EPA standards for certification as a commercial applicator of pesticides in the seed treatment category. The text discusses pests commonly associated with seeds; seed treatment pesticides; labels; chemicals and seed treatment equipment; requirements of federal and state seed laws;…

Seed Treatment. Bulletin 760.

ERIC Educational Resources Information Center

Lowery, Harvey C.

This manual gives a definition of seed treatment, the types of seeds normally treated, diseases and insects commonly associated with seeds, fungicides and insecticides used, types of equipment used for seed treatment, and information on labeling and coloring of treated seed, pesticide carriers, binders, stickers, and safety precautions. (BB)

A rare cause of recalcitrant coccydynia: benign dermoid cyst masquerading as coccygeal pain.

PubMed

Gaike, Chandrasekhar V; Kanna, Rishi M; Shetty, Ajoy P; Rajasekaran, S

2016-05-01

Coccydynia is a common entity in orthopedic practice, and various etiologies have been described for it. However, benign dermoid cyst causing coccydynia has not yet been reported. A 20-year-old male presented with typical symptoms of coccydynia recalcitrant to conservative treatment for 2 years. Since pain interfered with his daily activities, magnetic resonance imaging was performed which showed a circumscribed precoccygeal cystic lesion. The patient underwent coccygectomy along with cyst excision. Histological examination revealed features of benign dermoid cyst. After surgery, the patient had excellent relief of his symptoms. The case report identifies that the treating surgeon should be aware of benign dermoid cyst as one of the treatable but rare causes of intractable coccydynia, and MRI should be performed in patients with persistent coccygeal pain.

Adenylate and Nicotinamide Nucleotides in Developing Soybean Seeds During Seed-Fill 1

PubMed Central

Quebedeaux, Bruno

1981-01-01

Profiles of adenylate and nicotinamide nucleotides in soybean seeds were determined during seed-fill. The ATP content per seed increased during the early seed-filling stages to a level of 10 to 12 micrograms per seed. Seed ATP decreased after 40 days of development and reached its lowest level of less than 1 microgram at maturity. The ATP:ADP ratios were relatively constant at all seed development stages. Sharp increases in AMP levels during the late seed-fill stages were paralleled with a disappearance of ATP and ADP pools resulting in a reduced seed energy charge. Energy charge varied from the highest value of 0.78 at mid-seed-fill to less than 0.10 at maturity. Of the oxidized (NAD, NADP) and reduced (NADH, NADPH) nicotinamide nucleotide forms, NAD was the most abundant. Levels as high as 17.5 micrograms per seed were observed during the mid-seed-filling stages. NADP was found almost exclusively in the reduced form with a NADP: NADPH ratio of less than 0.35, whereas the reverse was noted for NAD which was found mainly in the oxidized form with a NAD:NADH ratio in the range of 5 to 25. NADP was detected in low concentrations compared to the other adenylate and nicotinamide nucleotides. The nicotinamide redox charge defined as (NADH + NADPH)/(NAD + NADH) + (NADP + NADPH) was calculated to express the state of the energy balance between the oxidized and reduced nicotinamide nucleotide forms. The nicotinamide redox charge varied between 0.15 and 0.30 during seed development and was significantly lower than that found for the adenylate energy charge. PMID:16661875

Chloroxyanion Residue on Seeds and Sprouts after Chlorine Dioxide Sanitation of Alfalfa Seed.

PubMed

Smith, David J; Herges, Grant R

2018-02-28

The effects of a 6-h chlorine dioxide sanitation of alfalfa seed (0, 50, 100, and 200 mg/kg seed) on total coliform bacteria, seed germination, and the presence of chlorate and perchlorate residues in seed rinse, seed soak, and alfalfa sprouts was determined. Chlorate residues in 20,000 mg/L calcium hypochlorite, commonly used to disinfect seed, were quantified. Chlorine dioxide treatment reduced (P < 0.05) total coliforms on seeds with no effect (P > 0.05) on germination. Dose-dependent sodium chlorate residues were present in seed rinse (4.1 to 31.2 μg/g seed) and soak (0.7 to 8.3 μg/g seed) waters, whereas chlorate residues were absent (LOQ 5 ng/g) in sprouts, except for 2 of 5 replicates from the high chlorine dioxide treatment. Copious chlorate residues were present (168 to 1260 mg/L) in freshly prepared 20,000 mg/L calcium hypochlorite solution, and storage at room temperature increased chlorate residues significantly (P < 0.01).

Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?

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

Morton, Daniel, E-mail: dmorton@bccancer.bc.ca; Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia; Hilts, Michelle

Purpose: To evaluate seed placement accuracy in permanent breast seed implant brachytherapy (PBSI), to identify any systematic errors and evaluate their effect on dosimetry. Methods and Materials: Treatment plans and postimplant computed tomography scans for 20 PBSI patients were spatially registered and used to evaluate differences between planned and implanted seed positions, termed seed displacements. For each patient, the mean total and directional seed displacements were determined in both standard room coordinates and in needle coordinates relative to needle insertion angle. Seeds were labeled according to their proximity to the anatomy within the breast, to evaluate the influence of anatomicmore » regions on seed placement. Dosimetry within an evaluative target volume (seroma + 5 mm), skin, breast, and ribs was evaluated to determine the impact of seed placement on the treatment. Results: The overall mean (±SD) difference between implanted and planned positions was 9 ± 5 mm for the aggregate seed population. No significant systematic directional displacements were observed for this whole population. However, for individual patients, systematic displacements were observed, implying that intrapatient offsets occur during the procedure. Mean displacements for seeds in the different anatomic areas were not found to be significantly different from the mean for the entire seed population. However, small directional trends were observed within the anatomy, potentially indicating some bias in the delivery. Despite observed differences between the planned and implanted seed positions, the median (range) V{sub 90} for the 20 patients was 97% (66%-100%), and acceptable dosimetry was achieved for critical structures. Conclusions: No significant trends or systematic errors were observed in the placement of seeds in PBSI, including seeds implanted directly into the seroma. Recorded seed displacements may be related to intrapatient setup adjustments. Despite

Calcium maelstrom: recalcitrant hypocalcaemia following rapid correction of thyrotoxicosis, exacerbated by pregnancy.

PubMed

Shin, Terry; Guerrero, Arthur F

2015-05-12

A 29-year-old pregnant woman with Graves' disease presented with severe persistent hypocalcaemia after thyroidectomy. Six months prior to presentation she was diagnosed with Graves' disease and remained uncontrolled with methimazole. She was confirmed pregnant prior to radioactive iodine ablation (RAI), and underwent total thyroidectomy during her second trimester. After surgery, continuous intravenous calcium infusion was required until delivery of the fetus allowed discontinuation at postoperative day 18, despite oral calcium and calcitriol administration. A total of 38 g of oral and 7.5 g of intravenous elemental calcium was administered. We report an unusual case of recalcitrant hypocalcaemia thought to be due to a combination of postoperative hypoparathyroidism, combined with thyrotoxic osteodystrophy and pregnancy, after surgical correction of Graves' disease. Increased vigilance and early calcium supplementation should be a priority in the management of these patients. 2015 BMJ Publishing Group Ltd.

Interactions between seed traits and digestive processes determine the germinability of bird-dispersed seeds

PubMed Central

Soons, Merel B.

2018-01-01

Waterbirds disperse a wide range of plant seeds via their guts, promoting biotic connectivity between isolated habitat patches. However, the intensity of digestive forces encountered by seeds, and therefore their potential to survive digestive tract passage, varies within and between waterbird species. Here, we investigate under controlled conditions how the interaction between seed traits and digestive strategies affect the germinability of seeds following waterbird-mediated dispersal. We exposed seeds of 30 wetland plant species to the main digestive processes in the dabbling duck digestive system: mechanical, chemical and intestinal digestion. These were simulated by 1) a pressure test and scarification treatment, 2) incubation in simulated gastric juice, and 3) incubation in intestinal contents of culled mallards (Anas platyrhynchos). We evaluated their separate and combined effects on seed germination, and identified the role of seed size and seed coat traits in resisting the digestive forces. Seeds were generally resistant to separate digestive processes, but highly sensitive to a combination. Resistance to mechanical break-down was reduced by up to 80% by chemical pre-treatment, especially for seeds with permeable coats. Scarified seeds were 12–17% more vulnerable to chemical and intestinal digestive processes than undamaged seeds. Large seeds and seeds with thin, permeable coats were particularly sensitive to chemical and intestinal digestion. These results indicate that efficient digestion of seeds requires multiple digestive processes. The gizzard, responsible for mechanical digestion, plays a key role in seed survival. Omnivorous birds, which have relatively light gizzards compared to pure herbivores or granivores, are thus most likely to disperse seeds successfully. Regardless of digestive strategy, small seeds with tough seed coats are most resistant to digestion and may be adapted to endozoochorous dispersal by waterbirds. PMID:29614085

Interactions between seed traits and digestive processes determine the germinability of bird-dispersed seeds.

PubMed

Kleyheeg, Erik; Claessens, Mascha; Soons, Merel B

2018-01-01

Waterbirds disperse a wide range of plant seeds via their guts, promoting biotic connectivity between isolated habitat patches. However, the intensity of digestive forces encountered by seeds, and therefore their potential to survive digestive tract passage, varies within and between waterbird species. Here, we investigate under controlled conditions how the interaction between seed traits and digestive strategies affect the germinability of seeds following waterbird-mediated dispersal. We exposed seeds of 30 wetland plant species to the main digestive processes in the dabbling duck digestive system: mechanical, chemical and intestinal digestion. These were simulated by 1) a pressure test and scarification treatment, 2) incubation in simulated gastric juice, and 3) incubation in intestinal contents of culled mallards (Anas platyrhynchos). We evaluated their separate and combined effects on seed germination, and identified the role of seed size and seed coat traits in resisting the digestive forces. Seeds were generally resistant to separate digestive processes, but highly sensitive to a combination. Resistance to mechanical break-down was reduced by up to 80% by chemical pre-treatment, especially for seeds with permeable coats. Scarified seeds were 12-17% more vulnerable to chemical and intestinal digestive processes than undamaged seeds. Large seeds and seeds with thin, permeable coats were particularly sensitive to chemical and intestinal digestion. These results indicate that efficient digestion of seeds requires multiple digestive processes. The gizzard, responsible for mechanical digestion, plays a key role in seed survival. Omnivorous birds, which have relatively light gizzards compared to pure herbivores or granivores, are thus most likely to disperse seeds successfully. Regardless of digestive strategy, small seeds with tough seed coats are most resistant to digestion and may be adapted to endozoochorous dispersal by waterbirds.

7 CFR 201.33 - Seed in bulk or large quantities; seed for cleaning or processing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... quantities; seed for cleaning or processing. (a) In the case of seed in bulk, the information required under... seeds. (b) Seed consigned to a seed cleaning or processing establishment, for cleaning or processing for... pertaining to such seed show that it is “Seed for processing,” or, if the seed is in containers and in...

7 CFR 201.33 - Seed in bulk or large quantities; seed for cleaning or processing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... quantities; seed for cleaning or processing. (a) In the case of seed in bulk, the information required under... seeds. (b) Seed consigned to a seed cleaning or processing establishment, for cleaning or processing for... pertaining to such seed show that it is “Seed for processing,” or, if the seed is in containers and in...

7 CFR 201.33 - Seed in bulk or large quantities; seed for cleaning or processing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... quantities; seed for cleaning or processing. (a) In the case of seed in bulk, the information required under... seeds. (b) Seed consigned to a seed cleaning or processing establishment, for cleaning or processing for... pertaining to such seed show that it is “Seed for processing,” or, if the seed is in containers and in...

7 CFR 201.33 - Seed in bulk or large quantities; seed for cleaning or processing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... quantities; seed for cleaning or processing. (a) In the case of seed in bulk, the information required under... seeds. (b) Seed consigned to a seed cleaning or processing establishment, for cleaning or processing for... pertaining to such seed show that it is “Seed for processing,” or, if the seed is in containers and in...

7 CFR 201.33 - Seed in bulk or large quantities; seed for cleaning or processing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... quantities; seed for cleaning or processing. (a) In the case of seed in bulk, the information required under... seeds. (b) Seed consigned to a seed cleaning or processing establishment, for cleaning or processing for... pertaining to such seed show that it is “Seed for processing,” or, if the seed is in containers and in...

Seed rain, soil seed bank, seed loss and regeneration of Castanopsis fargesii (Fagaceae) in a subtropical evergreen broad-leaved forest

Treesearch

Xiaojun Du; Qinfeng Guo; Xianming Gao; Keping Na

2007-01-01

Understanding the seed rain and seed loss dynamics in the natural condition has important significance for revealing the natural regeneration mechanisms.We conducted a 3-year field observation on seed rain, seed loss and natural regeneration of Castanopsis fargesii Franch., a dominant tree species in evergreen broad-leaved forests in Dujiangyan,...

Chloroxyanion residue on seeds and sprouts after chlorine dioxide sanitation of alfalfa seed

USDA-ARS?s Scientific Manuscript database

The effects of a 6-h chlorine dioxide sanitation of alfalfa seed (0, 50, 100, and 200 mg/kg seed) on total coliform bacteria, seed germination, and on the presence of chlorate and perchlorate residues in seed rinse, seed soak, and in alfalfa sprouts was determined. Chlorate residues in 20000 ppm cal...

Tree Seed Technology Training Course

Treesearch

F.T. Bonner; James A. Vozzo; W.W. Elam; S.B. Land

1994-01-01

This manual is intended primarily to train seed collectors, seed-plant managers, seed analysts, and nursery managers, but it can serve as a resource for any training course in forest regeneration. It includes both temperate and tropical tree species of all intended uses. The manual covers the following topics: seed biology, seed collection, seed handling, seed-quality...

Increasing seed size and quality by manipulating BIG SEEDS1 in legume species

PubMed Central

Ge, Liangfa; Yu, Jianbin; Wang, Hongliang; Luth, Diane; Bai, Guihua; Wang, Kan

2016-01-01

Plant organs, such as seeds, are primary sources of food for both humans and animals. Seed size is one of the major agronomic traits that have been selected in crop plants during their domestication. Legume seeds are a major source of dietary proteins and oils. Here, we report a conserved role for the BIG SEEDS1 (BS1) gene in the control of seed size and weight in the model legume Medicago truncatula and the grain legume soybean (Glycine max). BS1 encodes a plant-specific transcription regulator and plays a key role in the control of the size of plant organs, including seeds, seed pods, and leaves, through a regulatory module that targets primary cell proliferation. Importantly, down-regulation of BS1 orthologs in soybean by an artificial microRNA significantly increased soybean seed size, weight, and amino acid content. Our results provide a strategy for the increase in yield and seed quality in legumes. PMID:27791139

Conference Proceedings: Seed Ecology III - The Third International Society for Seed Science Meeting on Seeds and the Environment - "Seeds and Change"; June 20-June 24, 2010; Salt Lake City, Utah, USA

Treesearch

Rosemary Pendleton; Susan Meyer; Bitsy Schultz

2010-01-01

Seed Ecology III was held in Salt Lake City, Utah in June 2010, sharing the latest research on all aspects of seed ecology. Our meeting was organized around the theme "Seeds and Change." We welcomed contributions in any area of seed ecology. Our agenda also aimed to create bridges between seed ecology and plant conservation, restoration ecology, and global...

How seed orchard culture affects seed quality: experience with the southern pines

Treesearch

James P. Barnett

1996-01-01

Tree improvement programs have influenced significantly the quality of southern pine seeds produced when compared to collections from native stands. Seed orchard management practices such as fertilization can increase seed size and reduce seed dormancy. These result in the need for less complex pregermination treatments. Repeated cone collections from the same clones...

Genetic relatedness among developing seeds and intra fruit seed abortion in Dalbergia sissoo (Fabaceae).

PubMed

Mohana, G S; Shaanker, R U; Ganeshaiah, K N; Dayanandan, S

2001-07-01

Dalbergia sissoo, a wind-dispersed tropical tree, exhibits high intrafruit seed abortion. Of the four to five ovules in the flower, generally one and occasionally two or three develop to maturity. It has been proposed that the seed abortion is a consequence of intense sibling competition for maternal resources and that this competition occurs as an inverse function of the genetic relatedness among the developing seeds. Accordingly, developing seeds compete intensely when they are genetically less related but tend to develop together when genetically more related. We tested this hypothesis by comparing the genetic similarity among the pairs of seeds developing within a pod with that among (a) random pairs from the pool of all seeds, (b) random pairs from single-seeded pods, and (c) random pairs from two-seeded pods, using both randomly amplified polymorphic DNA (RAPD) and isozymes in five trees. We found that the pairs of seeds developing within a pod are genetically more similar than any random pairs of seeds in a tree. Thus the formation of two-seeded pods appear to be associated with increased genetic relatedness among the developing seeds. We discuss the results in the context of possible fitness advantages and then discuss the possible mechanisms that promote tolerance among related seeds.

Restoration seed reserves for assisted gene flow within seed orchards

Treesearch

C.S. Echt; B.S. Crane

2017-01-01

Changing climate and declining forest populations imperil the future of certain forest tree species. To complement forest management and genetic conservation plans, we propose a new paradigm for seedling seed orchards: foster genetic mixing among a variety of seed sources to increase genetic diversity and adaptive potential of seed supplies used for forest restoration...

Automated seed manipulation and planting

NASA Technical Reports Server (NTRS)

Garcia, Ray; Herrera, Javier; Holcomb, Scott; Kelly, Paul; Myers, Scott; Rosendo, Manny; Sivitz, Herbert; Wolsefer, Dave

1988-01-01

The Mechanical Division fabricated three seed separators utilizing pressure gradients to move and separate wheat seeds. These separators are called minnow buckets and use air, water, or a combination of both to generate the pressure gradient. Electrostatic fields were employed in the seed separator constructed by the Electrical Division. This separator operates by forcing a temporary electric dipole on the wheat seeds and using charged electrodes to attract and move the seeds. Seed delivery to the hydroponic growth tray is accomplished by the seed cassette. The cassette is compatible with all the seed separators, and it consists of a plastic tube threaded with millipore filter paper. During planting operations, the seeds are placed in an empty cassette. The loaded cassette is then placed in the growth tray and nutrient solution provided. The solution wets the filter paper and capillary action draws the nutrients up to feed the seeds. These seeding systems were tested and showed encouraging results. Seeds were effectively separated and the cassette can support the growth of wheat plants. Problems remaining to be investigated include improving the success of delivering the seeds to the cassette and providing adequate spacing between seeds for the electric separator.

Wrinkled alfalfa seeds harbor more aerobic bacteria and are more difficult to sanitize than smooth seeds.

PubMed

Charkowski, A O; Sarreal, C Z; Mandrell, R E

2001-09-01

At least 14 separate outbreaks of food poisoning attributed to either Salmonella enterica or Escherichia coli O157:H7 have been traced to sprouts in the past decade. Seeds contaminated with human pathogens caused most of these outbreaks, thus many sprout growers are now treating alfalfa seeds with the sanitizing agent, calcium hypochlorite (Ca[OCl]2), prior to sprouting. The efficacy of alfalfa seed sanitation varies between seed lots and between seeds within each lot. Alfalfa seeds from different seed lots were sorted by type in an effort to determine if certain seed types carry more aerobic bacteria than other seed types. Seeds with a wrinkled type, characteristic of lygus bug damage, had significantly higher levels of culturable aerobic bacteria and were more difficult to sanitize than smooth, healthy seeds. After sanitation, wrinkled alfalfa seeds that had been inoculated with S. enterica ser. Newport carried significantly higher levels of Salmonella Newport than smooth seeds. If S. enterica is present on wrinkled seeds in naturally contaminated seed lots, it may be difficult to chemically sanitize the seed lot. Removal of the wrinkled alfalfa seeds from the seed lots, perhaps by adapting color sorting equipment similar to that used to sort rice grains and other seeds, should reduce the level of aerobic bacteria in seed lots and may result in lower levels of human pathogens on contaminated alfalfa seeds.

Seed-specific overexpression of AtFAX1 increases seed oil content in Arabidopsis.

PubMed

Tian, Yinshuai; Lv, Xueyan; Xie, Guilan; Zhang, Jing; Xu, Ying; Chen, Fang

2018-06-02

Biosynthesis of plant seed oil is accomplished through the coordinate action of multiple enzymes in multiple subcellular compartments. Fatty acid (FA) has to be transported from plastid to endoplasmic reticulum (ER) for TAG synthesis. However, the role of plastid FA transportation during seed oil accumulation has not been evaluated. AtFAX1 (Arabidopsis fatty acid export1) mediated the FA export from plastid. In this study, we overexpressed AtFAX1 under the control of a seed specific promoter in Arabidopsis. The resultant overexpression lines (OEs) produced seeds which contained 21-33% more oil and 24-30% more protein per seed than those of the wild type (WT). The increased oil content was probably because of the enhanced FA and TAG synthetic activity. The seed size and weight were both increased accordingly. In addition, the seed number per silique and silique number per plant had no changes in transgenic plants. Taken together, our results demonstrated that seed specific overexpression of AtFAX1 could promote oil accumulation in Arabidopsis seeds and manipulating FA transportation is a feasible strategy for increasing the seed oil content. Copyright © 2018 Elsevier Inc. All rights reserved.

A 400-year phytolith-based reconstruction of wild rice (Zizania palustris) abundance from Mud Lake core sediments, Fond du Lac Band of Lake Superior Chippewa Reservation, Minnesota, USA.

NASA Astrophysics Data System (ADS)

Munoz, R.; Caylor, E.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

2014-12-01

Wild rice (Zizania palustris L.) is an aquatic grass with spiritual and subsistence significance to Native people of the Great Lakes region of North America. Mud Lake (Mashkiigwaagamaag), located on the Fond du Lac Band of Lake Superior Chippewa Reservation in Carlton County, Minnesota, USA, once supported an extensive population of wild rice (manoomin). However, early 20th century attempts to ditch and drain surrounding wetlands for landuse intensification severely altered the natural hydrological system that supports wild rice. Fond du Lac Resource Management (FDLRM) technicians are currently working to increase the wild rice population in Mud Lake. As part of these efforts, this phytolith study was undertaken to better understand how wild rice abundance has fluctuated over the past 400 years, with particular emphasis on the 19th and 20th centuries. Phytoliths are microscopic opal silica plant remains that are incorporated into soils and lake sediments after the plant-parts that contain them decay. Wild rice produces phytolith morphotypes that are unequivocally diagnostic. Mud Lake core MNMN-MUD11-1C-1P-1 (46°43'38.39"N, 92°42'2.45"W) was piston cored by LacCore (National Lacustrine Core Facility) and FDLRM technicians on 24 May 2011. Initial core descriptions, multi-sensor core logging, phytolith sampling and phytolith extractions were completed during the summer of 2014 at LacCore. Wild rice phytolith identification and quantification was conducted on twelve samples using brightfield microscopy at 400x magnification. Wild rice phytolith concentration values ranged from 68 to 2,300 phytoliths/cm3. Wild rice accumulation rates ranged from 9 to 383 phytoliths/ cm2/yr, peaking in 1952 AD. Wild rice abundance in Mud Lake appears to be influenced by a complex set of variables that include anthropogenic disturbance, climatic events and aquatic plant community succession.

Seed potato production system in Japan, starting from foundation seed of potato

PubMed Central

Kawakami, Tsukasa; Oohori, Hidemiki; Tajima, Kazuyuki

2015-01-01

Potato is one of the staple crops cultivated in upland farming in Japan and is propagated vegetatively by means of tubers. However once infected with diseases, potato yield decreases significantly. And one seed potato can produce approximately only 10 potato tubers. To improve the production system of seed potatoes in Japan, Japanese government established a three-stage propagation system for the production and distribution of healthy and disease-free seed potatoes. The National Center for Seeds and Seedlings (NCSS) has a role for the production of foundation seed potatoes and strictly manages the production in isolated fields that are treated thoroughly to control pests and diseases. Recently though the distribution of foundation seed potatoes is decreasing, the number of varieties of foundation seed potatoes has increased steadily. And new varieties of potato adapted various requirements, including resistance of the golden potato cyst nematode, have been increasing. Therefore, NCSS is introducing a new method of producing minitubers (MnTs) by using hydroponic cultivation greenhouse to increase the efficiency of propagation and to rapidly disseminate these new potato varieties. In this review, we describe a seed potato production system in Japan and the production of foundation seed potatoes as an important role of NCSS. PMID:25931977

Saving seed microbiomes.

PubMed

Berg, Gabriele; Raaijmakers, Jos M

2018-05-01

Plant seeds are home to diverse microbial communities whose composition is determined by plant genotype, environment, and management practices. Plant domestication is now recognized as an important driver of plant-associated microbial diversity. To what extent and how domestication affects seed microbiomes is less well studied. Here we propose a 'back-to-the-future' approach to harness seed microbiomes of wild relatives of crop cultivars to save and re-instate missing beneficial seed microbes for improved plant tolerance to biotic and abiotic stress.

Physical Methods for Seed Invigoration: Advantages and Challenges in Seed Technology

PubMed Central

Araújo, Susana de Sousa; Paparella, Stefania; Dondi, Daniele; Bentivoglio, Antonio; Carbonera, Daniela; Balestrazzi, Alma

2016-01-01

In the context of seed technology, the use of physical methods for increasing plant production offers advantages over conventional treatments based on chemical substances. The effects of physical invigoration treatments in seeds can be now addressed at multiple levels, ranging from morpho-structural aspects to changes in gene expression and protein or metabolite accumulation. Among the physical methods available, “magneto-priming” and irradiation with microwaves (MWs) or ionizing radiations (IRs) are the most promising pre-sowing seed treatments. “Magneto-priming” is based on the application of magnetic fields and described as an eco-friendly, cheap, non-invasive technique with proved beneficial effects on seed germination, vigor and crop yield. IRs, as γ-rays and X-rays, have been widely regarded as a powerful tool in agricultural sciences and food technology. Gamma-rays delivered at low dose have showed to enhance germination percentage and seedling establishment, acting as an actual ‘priming’ treatment. Different biological effects have been observed in seeds subjected to MWs and X-rays but knowledge about their impact as seed invigoration agent or stimulatory effects on germination need to be further extended. Ultraviolet (UV) radiations, namely UV-A and UV-C have shown to stimulate positive impacts on seed health, germination, and seedling vigor. For all mentioned physical treatments, extensive fundamental and applied research is still needed to define the optimal dose, exposition time, genotype- and environment-dependent irradiation conditions. Electron paramagnetic resonance has an enormous potential in seed technology not fully explored to monitor seed invigoration treatments and/or identifying the best suitable irradiation dose or time-point to stop the treatment. The present manuscript describes the use of physical methods for seed invigoration, while providing a critical discussion on the constraints and advantages. The future perspectives

Seed source, seed traits, and frugivore habits: Implications for dispersal quality of two sympatric primates.

PubMed

Benítez-Malvido, Julieta; González-Di Pierro, Ana Ma; Lombera, Rafael; Guillén, Susana; Estrada, Alejandro

2014-06-01

• Premise of the study: Frugivore selection of fruits and treatment of seeds together with seed deposition site are crucial for the population dynamics of vertebrate-dispersed plants. However, frugivore species may influence dispersal quality differently even when feeding on the same fruit species and, while animals disperse some seeds, others simply fall beneath the parent plant.• Methods: In southern Mexico, we investigated to see if within-species seed traits (i.e., length, width, weight, and volume) and germination success differed according to seed source. For five tropical tree species we obtained ingested seeds from two sources, howler monkey (Alouatta pigra) and spider monkey (Ateles geoffroyi) feces; and noningested seeds from two sources, the ground and tree crowns (with predispersed seeds used as control).• Key results: A principal components' analysis showed that traits of seeds ingested by howler monkeys differed from other sources while seeds ingested by spider monkeys were similar to noningested seeds. Howlers consumed on average the larger seeds in Ampelocera hottlei, Brosimum lactescens, and Dialium guianense. Both primate species consumed the smaller seeds in Spondias mombin, while no seed trait differences among seed sources were found in Spondias radlkoferi. For all five tree species, germination rate was greatest for seeds ingested by howler monkeys.• Conclusions: For the studied plant species, seed ingestion by howler monkeys confers higher dispersal quality than ingestion by spider monkeys or nondispersal. Dispersal services of both primate species, however, are not redundant and may contribute to germination heterogeneity within plant populations in tropical forests. © 2014 Botanical Society of America, Inc.

Cone and seed yields in white spruce seed production areas

Treesearch

John A. Pitcher

1966-01-01

The source of seed is an important consideration in the reforestation program on the National Forests in the North Central Region. Thirty-five seed production areas have been set up in the Region, along the lines proposed by the North Central Forest Experiment Station, to provide control of seed source. Red pine, white pine, shortleaf and loblolly pine, and white...

Magnetic stimulation of marigold seed

NASA Astrophysics Data System (ADS)

Afzal, I.; Mukhtar, K.; Qasim, M.; Basra, S. M. A.; Shahid, M.; Haq, Z.

2012-10-01

The effects of magnetic field treatments of French marigold seeds on germination, early seedling growth and biochemical changes of seedlings were studied under controlled conditions. For this purpose, seeds were exposed to five different magnetic seed treatments for 3 min each. Most of seed treatments resulted in improved germination speed and spread, root and shoot length, seed soluble sugars and a-amylase activity. Magnetic seed treatment with 100 mT maximally improved germination, seedling vigour and starch metabolism as compared to control and other seed treatments. In emergence experiment, higher emergence percentage (4-fold), emergence index (5-fold) and vigorous seedling growth were obtained in seeds treated with 100 mT. Overall, the enhancement of marigold seeds by magnetic seed treatment with 100 mT could be related to enhanced starch metabolism. The results suggest that magnetic field treatments of French marigold seeds have the potential to enhance germination, early growth and biochemical parameters of seedlings.

Seed size selection by olive baboons.

PubMed

Kunz, Britta Kerstin; Linsenmair, Karl Eduard

2008-10-01

Seed size is an important plant fitness trait that can influence several steps between fruiting and the establishment of a plant's offspring. Seed size varies considerably within many plant species, yet the relevance of the trait for intra-specific fruit choice by primates has received little attention. Primates may select certain seed sizes within a species for a number of reasons, e.g. to decrease indigestible seed load or increase pulp intake per fruit. Olive baboons (Papio anubis, Cercopithecidae) are known to select seed size in unripe and mature pods of Parkia biglobosa (Mimosaceae) differentially, so that pods with small seeds, and an intermediate seed number, contribute most to dispersal by baboons. We tested whether olive baboons likewise select for smaller ripe seeds within each of nine additional fruit species whose fruit pulp baboons commonly consume, and for larger seeds in one species in which baboons feed on the seeds. Species differed in fruit type and seed number per fruit. For five of these species, baboons dispersed seeds that were significantly smaller than seeds extracted manually from randomly collected fresh fruits. In contrast, for three species, baboons swallowed seeds that were significantly longer and/or wider than seeds from fresh fruits. In two species, sizes of ingested seeds and seeds from fresh fruits did not differ significantly. Baboons frequently spat out seeds of Drypetes floribunda (Euphorbiaceae) but not those of other plant species having seeds of equal size. Oral processing of D. floribunda seeds depended on seed size: seeds that were spat out were significantly larger and swallowed seeds smaller, than seeds from randomly collected fresh fruits. We argue that seed size selection in baboons is influenced, among other traits, by the amount of pulp rewarded per fruit relative to seed load, which is likely to vary with fruit and seed shape.

Biofilm-Related Infections: Bridging the Gap between Clinical Management and Fundamental Aspects of Recalcitrance toward Antibiotics

PubMed Central

Lebeaux, David; Ghigo, Jean-Marc

2014-01-01

SUMMARY Surface-associated microbial communities, called biofilms, are present in all environments. Although biofilms play an important positive role in a variety of ecosystems, they also have many negative effects, including biofilm-related infections in medical settings. The ability of pathogenic biofilms to survive in the presence of high concentrations of antibiotics is called “recalcitrance” and is a characteristic property of the biofilm lifestyle, leading to treatment failure and infection recurrence. This review presents our current understanding of the molecular mechanisms of biofilm recalcitrance toward antibiotics and describes how recent progress has improved our capacity to design original and efficient strategies to prevent or eradicate biofilm-related infections. PMID:25184564

Improving Soil Seed Bank Management.

PubMed

Haring, Steven C; Flessner, Michael L

2018-05-08

Problems associated with simplified weed management motivate efforts for diversification. Integrated weed management uses fundamentals of weed biology and applied ecology to provide a framework for diversified weed management programs; the soil seed bank comprises a necessary part of this framework. By targeting seeds, growers can inhibit the propagule pressure on which annual weeds depend for agricultural invasion. Some current management practices affect weed seed banks, such as crop rotation and tillage, but these tools are often used without specific intention to manage weed seeds. Difficulties quantifying the weed seed bank, understanding seed bank phenology, and linking seed banks to emerged weed communities challenge existing soil seed bank management practices. Improved seed bank quantification methods could include DNA profiling of the soil seed bank, mark and recapture, or 3D LIDAR mapping. Successful and sustainable soil seed bank management must constrain functionally diverse and changing weed communities. Harvest weed seed controls represent a step forward, but over-reliance on this singular technique could make it short-lived. Researchers must explore tools inspired by other pest management disciplines, such as gene drives or habitat modification for predatory organisms. Future weed seed bank management will combine multiple complementary practices that enhance diverse agroecosystems. This article is protected by copyright. All rights reserved.

[Effects of illumination and seed-soaking reagent on seed germination of Solanum nigrum].

PubMed

Yang, Chuan-Jie; Wei, Shu-He; Zhou, Qi-Xing; Hu, Ya-Hu; Niu, Rong-Cheng

2009-05-01

To explore a rapid seed germination method for hyperaccumulator Solanum nigrum, a germination experiment with different illumination and seed-soaking treatments was conducted in constant temperature box and greenhouse, with filter as burgeon base. Under illumination, the germination rate was about 5 times high of that without illumination (P < 0.05), indicating that illumination was one of the prerequisites for the seed germination of S. nigrum. All test seed-soaking reagents could significantly improve the germination rate of S. nigrum (P < 0.05), with the best effect of H2O2. The seeds treated with H2O2 had the shortest germination time. The germination rate of seeds soaked but without cleaning was 2-3 times as high as that of seeds soaked and cleaned with water.

CT, MR, and ultrasound image artifacts from prostate brachytherapy seed implants: The impact of seed size

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

Robertson, Andrew K. H.; Basran, Parminder S.; Thomas, Steven D.

Purpose: To investigate the effects of brachytherapy seed size on the quality of x-ray computed tomography (CT), ultrasound (US), and magnetic resonance (MR) images and seed localization through comparison of the 6711 and 9011 {sup 125}I sources. Methods: For CT images, an acrylic phantom mimicking a clinical implantation plan and embedded with low contrast regions of interest (ROIs) was designed for both the 0.774 mm diameter 6711 (standard) and the 0.508 mm diameter 9011 (thin) seed models (Oncura, Inc., and GE Healthcare, Arlington Heights, IL). Image quality metrics were assessed using the standard deviation of ROIs between the seeds andmore » the contrast to noise ratio (CNR) within the low contrast ROIs. For US images, water phantoms with both single and multiseed arrangements were constructed for both seed sizes. For MR images, both seeds were implanted into a porcine gel and imaged with pelvic imaging protocols. The standard deviation of ROIs and CNR values were used as metrics of artifact quantification. Seed localization within the CT images was assessed using the automated seed finder in a commercial brachytherapy treatment planning system. The number of erroneous seed placements and the average and maximum error in seed placements were recorded as metrics of the localization accuracy. Results: With the thin seeds, CT image noise was reduced from 48.5 {+-} 0.2 to 32.0 {+-} 0.2 HU and CNR improved by a median value of 74% when compared with the standard seeds. Ultrasound image noise was measured at 50.3 {+-} 17.1 dB for the thin seed images and 50.0 {+-} 19.8 dB for the standard seed images, and artifacts directly behind the seeds were smaller and less prominent with the thin seed model. For MR images, CNR of the standard seeds reduced on average 17% when using the thin seeds for all different imaging sequences and seed orientations, but these differences are not appreciable. Automated seed localization required an average ({+-}SD) of 7.0 {+-} 3

Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy

PubMed Central

Martínez-Andújar, Cristina; Ordiz, M. Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N.; Nonogaki, Hiroyuki

2011-01-01

Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism. PMID:21969557

Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy.

PubMed

Martínez-Andújar, Cristina; Ordiz, M Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N; Nonogaki, Hiroyuki

2011-10-11

Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.

Seed-predator satiation and Janzen-Connell effects vary with spatial scales for seed-feeding insects.

PubMed

Xiao, Zhishu; Mi, Xiangcheng; Holyoak, Marcel; Xie, Wenhua; Cao, Ke; Yang, Xifu; Huang, Xiaoqun; Krebs, Charles J

2017-01-01

The Janzen-Connell model predicts that common species suffer high seed predation from specialized natural enemies as a function of distance from parent trees, and consequently as a function of conspecific density, whereas the predator satiation hypothesis predicts that seed attack is reduced due to predator satiation at high seed densities. Pre-dispersal predation by insects was studied while seeds are still on parent trees, which represents a frequently overlooked stage in which seed predation occurs. Reproductive tree density and seed production were investigated from ten Quercus serrata populations located in south-west China, quantifying density-dependent pre-dispersal seed predation over two years by three insect groups. Acorn infestation was nearly twice as high in the low-seed year as that in the high-seed year, with considerable spatio-temporal variation in the direction and magnitude of density-dependent pre-dispersal seed predation evident. Across whole populations of trees, a high density of reproductive trees caused predator satiation and reduced insect attack in the high-seed year. Within individual trees, and consistent with the Janzen-Connell model, overall insect seed predation was positively correlated with seed production in the low-seed year. In addition, there was variation among insect taxa, with positive density-dependent seed predation by Curculio weevils in the high-seed year and moths in the low-seed year, but apparent density independence by Cyllorhynchites weevils in both years. The overall trend of negative density-dependent, pre-dispersal seed predation suggests that predator satiation limited the occurrence of Janzen-Connell effects across Q. serrata populations. Such effects may have large impacts on plant population dynamics and tree diversity, depending on the extent to which they are reduced by counteracting positive density-dependent predation for seeds on individual trees and other factors affecting successful recruitment. © The

Timing of seed dispersal and seed dormancy in Brazilian savanna: two solutions to face seasonality.

PubMed

Escobar, Diego F E; Silveira, Fernando A O; Morellato, Leonor Patricia C

2018-05-11

The relationship between fruiting phenology and seed dispersal syndrome is widely recognized; however, the interaction of dormancy classes and plant life-history traits in relation to fruiting phenology and seed dispersal is understudied. Here we examined the relationship between fruiting season and seed dormancy and how this relationship is modulated by dormancy classes, dispersal syndromes, seed mass and seed moisture content in a Brazilian savanna (cerrado). Dormancy classes (non-dormancy and physical, morphological, morphophysiological, physiological and physiophysical dormancy) of 34 cerrado species were experimentally determined. Their seed dispersal syndrome (autochory, anemochory, zoochory), dispersal season (rainy, dry, rainy-to-dry and dry-to-rainy transitions), seed mass and moisture contents, and the estimated germination date were also determined. Log-linear models were used to evaluate how dormancy and dormancy classes are related to dispersal season and syndrome. The proportions of dormant and non-dormant species were similar in cerrado. The community-estimated germination date was seasonal, occurring at the onset of rainy season. Overall, anemochorous non-dormant species released seeds during the dry-to-rainy transition; autochorous physically dormant species dispersed seeds during the dry season and rainy-to-dry transition; zoochorous species dispersed non-dormant seeds during the dry and rainy seasons, while species with morphological, morphophysiological or physiological dormancy dispersed seeds in the transitional seasons. Seed mass differed among dispersal seasons and dormancy classes, but seed moisture content did not vary with dispersal syndrome, season or dormancy class. The beginning of the rainy season was the most favourable period for seed germination in cerrado, and the germination phenology was controlled by both the timing of seed dispersal and seed dormancy. Dormancy class was influenced by dispersal syndrome and season. Moreover

Responses of seed germination, seedling growth, and seed yield traits to seed pretreatment in maize (Zea mays L.).

PubMed

Tian, Yu; Guan, Bo; Zhou, Daowei; Yu, Junbao; Li, Guangdi; Lou, Yujie

2014-01-01

A series of seed priming experiments were conducted to test the effects of different pretreatment methods to seed germination, seedling growth, and seed yield traits in maize (Zea mays L.). Results indicated that the seeds primed by gibberellins (GA), NaCl, and polyethylene glycol (PEG) reagents showed a higher imbibitions rate compared to those primed with water. The final germination percentage and germination rate varied with different reagents significantly (P < 0.05). The recommended prime reagents were GA at 10 mg/L, NaCl at 50 mM, and PEG at 15% on account of germination experiment. 15% PEG priming reagent increased shoot and root biomass of maize seedling. The shoot biomass of seedlings after presoaking the seeds with NaCl reagent was significantly higher than the seedlings without priming treatment. No significant differences of plant height, leaf number, and hundred-grain weight were observed between control group and priming treatments. Presoaking with water, NaCl (50 mM), or PEG (15%) significantly increased the hundred-grain weight of maize. Therefore, seed pretreatment is proved to be an effective technique to improve the germination performance, seedling growth, and seed yield of maize. However, when compared with the two methods, if immediate sowing is possible, presoaking is recommended to harvest better benefits compared to priming method.

Transcriptome analyses of seed development in grape hybrids reveals a possible mechanism influencing seed size.

PubMed

Wang, Li; Hu, Xiaoyan; Jiao, Chen; Li, Zhi; Fei, Zhangjun; Yan, Xiaoxiao; Liu, Chonghuai; Wang, Yuejin; Wang, Xiping

2016-11-09

Seedlessness in grape (Vitis vinifera) is of considerable commercial importance for both the table grape and processing industries. Studies to date of grape seed development have been made certain progress, but many key genes have yet to be identified and characterized. In this study we analyzed the seed transcriptomes of progeny derived from the V. vinifera seeded maternal parent 'Red Globe' and the seedless paternal parent 'Centennial seedless' to identify genes associated with seedlessness. A total of 6,607 differentially expressed genes (DEGs) were identified and examined from multiple perspectives, including expression patterns, Gene Ontology (GO) annotations, pathway enrichment, inferred hormone influence and epigenetic regulation. The expression data of hormone-related genes and hormone level measurement reveals the differences during seed development between seedless and seeded progeny. Based on both our results and previous studies of A. thaliana seed development, we generated network maps of grape seed-related DEGs, with particular reference to hormone balance, seed coat and endosperm development, and seed identity complexes. In summary, the major differences identified during seed development of seedless and seeded progeny were associated with hormone and epigenetic regulation, the development of the seed coat and endosperm, and the formation of seed identity complexes. Overall the data provides insights into the possible molecular mechanism controlling grape seed size, which is of great importance for both basic research and future translation applications in the grape industry.

Seed traits and taxonomic relationships determine the occurrence of mutualisms versus seed predation in a tropical forest rodent and seed dispersal system.

PubMed

Wang, Zhenyu; Cao, Lin; Zhang, Zhibin

2014-06-01

Although many studies have been carried out on plant-animal mutualistic assemblages, the roles of functional traits and taxonomy in determining both whether interactions involve mutualisms or predation and the structure of such assemblages are unclear. We used semi-natural enclosures to quantitatively assess the interaction strengths between seeds of 8 sympatric tree species and 4 rodent species in a tropical forest in Xishuangbanna, Yunnan, Southwest China. We found 2 clusters of species in the seed-rodent network represented by 2 genera in the Fagaceae (Castanopsis, Lithocarpus). Compared to seeds of 3 Castanopsis species, seeds with heavy weight, hard coat or caloric content (including 3 Lithocarpus species) were eaten less and more frequently hoarded by rodents. In turn, hoarded seeds showed less predation and more mutualism with rodents. Our results suggest that seed traits significantly affected the hoarding behavior of rodents, and, consequently, the occurrence of mutualisms and predation as well as assemblage structure in the plant-animal seed dispersal system. Taxonomically-related species with similar seed traits as functional groups belong to the same substructures in the assemblage. Our results indicate that both seed traits and taxonomic relationships may simplify thinking about seed dispersal systems by helping to elucidate whether interactions are likely to be dominated by predation or mutualism. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

[Study on influence factors of seed germination and seeding growth of Lonicera macranthoides].

PubMed

Xu, Jin; Zhang, Ying; Cui, Guang-Lin; She, Yue-Hui; Li, Long-Yun

2016-01-01

In order to improve reproductive efficiency and quality standard, the influence factors of seed germination and seeding growth of Lonicera macranthoides werew studied. The fruit and seed morphological characteristics of L. macranthoides were observed, the seed water absorbing capacity was determined, and different wet sand stratification time, temperature and germination bed treatment were set up. The effects of the parameters on seed germination and seedling growth were analysed. There was no obstacles of water absorption on L. macranthoides seed, quantity for 22 h water absorption was close to saturation. In the first 80 d, with the increase of the stratification time, seed initial germination time was shortened, germination rate and germination potential was improved. Stratification for 100 d, germination rate decreased. At 15 ℃, seed germination and seedling growth indicators were the best. The seedling cotyledon width in light was significantly higher than that in dark. Seeds on the top of paper and top of sand germination rate, germination potential, and germination index was significantly higher than that of other germination bed and mildew rate is low. The optimal conditions of seeds germination test was stratified in 4 ℃ wet sand for 80 d, 15 ℃ illuminate culture on the top of paper or top of sand. The first seeding counting time was the 4th day after beginning the test, the final time was the 23th day. The germination potential statistical time was the 13th day after beginning the test. Copyright© by the Chinese Pharmaceutical Association.

Frugivores bias seed-adult tree associations through nonrandom seed dispersal: a phylogenetic approach.

PubMed

Razafindratsima, Onja H; Dunham, Amy E

2016-08-01

Frugivores are the main seed dispersers in many ecosystems, such that behaviorally driven, nonrandom patterns of seed dispersal are a common process; but patterns are poorly understood. Characterizing these patterns may be essential for understanding spatial organization of fruiting trees and drivers of seed-dispersal limitation in biodiverse forests. To address this, we studied resulting spatial associations between dispersed seeds and adult tree neighbors in a diverse rainforest in Madagascar, using a temporal and phylogenetic approach. Data show that by using fruiting trees as seed-dispersal foci, frugivores bias seed dispersal under conspecific adults and under heterospecific trees that share dispersers and fruiting time with the dispersed species. Frugivore-mediated seed dispersal also resulted in nonrandom phylogenetic associations of dispersed seeds with their nearest adult neighbors, in nine out of the 16 months of our study. However, these nonrandom phylogenetic associations fluctuated unpredictably over time, ranging from clustered to overdispersed. The spatial and phylogenetic template of seed dispersal did not translate to similar patterns of association in adult tree neighborhoods, suggesting the importance of post-dispersal processes in structuring plant communities. Results suggest that frugivore-mediated seed dispersal is important for structuring early stages of plant-plant associations, setting the template for post-dispersal processes that influence ultimate patterns of plant recruitment. Importantly, if biased patterns of dispersal are common in other systems, frugivores may promote tree coexistence in biodiverse forests by limiting the frequency and diversity of heterospecific interactions of seeds they disperse. © 2016 by the Ecological Society of America.

Needs of Seeds

ERIC Educational Resources Information Center

Keeley, Page

2011-01-01

The "Needs of Seeds" formative assessment probe can be used to find out whether students recognize that seeds have needs both similar to and different from plants and other living organisms (Keeley, Eberle, and Tugel 2007). The probe reveals whether students overgeneralize the needs of seeds by assuming they have the same needs as the adult plants…

Intralesional immunotherapy with tuberculin purified protein derivative (PPD) in recalcitrant wart: A randomized, placebo-controlled, double-blind clinical trial including an extra group of candidates for cryotherapy.

PubMed

Amirnia, Mehdi; Khodaeiani, Effat; Fouladi, Daniel F; Masoudnia, Sima

2016-01-01

Due to paucity of randomized clinical trials, intralesional immunotherapy has not been yet accepted as a standard therapeutic method. To examine the efficacy and safety of intralesional immunotherapy with tuberculin purified protein derivative (PPD) for treating recalcitrant wart. In this randomized, placebo-controlled, double-blind clinical trial, a total of 69 patients with recalcitrant warts received either intralesional PPD antigen (n = 35) or intralesional saline (n = 34) for six times at 2-week intervals. A third group of candidates for cryotherapy (n = 33) was also included. The decrease in lesion size (good: complete response, intermediate: 50-99% improvement, poor: <50% improvement), adverse effects and recurrence within 6-month follow-up were documented. At the final session, good, intermediate and poor responses were observed in 77.1%, 22.9% and 0% of the PPD patients; 0%, 14.7% and 85.3% of the placebo patients and 18.2%, 33.3% and 48.5% of the cryotherapy patients, respectively (PPD versus placebo: p < 0.001; PPD versus cryotherapy: p < 0.001). No significant complication was seen in the PPD group. The recurrence rate was 8.6%, 5.9% and 24.2% in the PPD, placebo and cryotherapy groups, respectively (p > 0.05). Intralesional immunotherapy with PPD antigen is highly effective and safe for treating recalcitrant warts. IRCT201407089844N3 in the Iranian Registry of Clinical Trials (IRCT).

The earliest seeds

USGS Publications Warehouse

Gillespie, W.H.; Rothwell, G.W.; Scheckler, S.E.

1981-01-01

Lagenostomalean-type seeds in bifurcating cupule systems have been discovered in the late Devonian Hampshire Formation of Randolph County, West Virginia, USA (Fig. 1). The associated megaflora, plants from coal balls, and vertebrate and invertebrate faunas demonstrate that the material is Famennian; the microflora indicates a more specific Fa2c age. Consequently, these seeds predate Archaeosperma arnoldii1 from the Fa2d of northeastern Pennsylvania, the oldest previously reported seed. By applying precision fracture, transfer, de??gagement, and thin-section techniques to selected cupules from the more than 100 specimens on hand, we have determined the three-dimensional morphology and histology of the seeds (Fig. 2a-h, k) and cupule systems. A comparison with known late Devonian to early Carboniferous seeds reveals that ours are more primitively organized than all except Genomosperma2,3. ?? 1981 Nature Publishing Group.

Seeds in space experiment results

NASA Technical Reports Server (NTRS)

Alston, Jim A.

1991-01-01

Two million seeds of 120 different varieties representing 106 species, 97 genera, and 55 plant families were flown aboard the Long Duration Exposure Facility (LDEF). The seeds were housed on the space exposed experiment developed for students (SEEDS) tray in sealed canister number six and in two small vented canisters. The tray was in the F-2 position. The seeds were germinated and the germination rates and development of the resulting plants compared to the control seed that stayed in Park Seed's seed storage facility. The initial results are presented. There was a better survival rate in the sealed canister in space than in the storage facility at Park Seed. At least some of the seeds in each of the vented canisters survived the exposure to vacuum for almost six years. The number of observed apparent mutations was very low.

Seed Rain and Seed Bank Reveal that Seed Limitation Strongly Influences Plant Community Assembly in Grasslands

PubMed Central

Marteinsdóttir, Bryndís

2014-01-01

Dispersal is an important factor in plant community assembly, but assembly studies seldom include information on actual dispersal into communities, i.e. the local propagule pool. The aim of this study was to determine which factors influence plant community assembly by focusing on two phases of the assembly process: the dispersal phase and the establishment phase. At 12 study sites in grazed ex-arable fields in Sweden the local plant community was determined and in a 100-m radius around the centre of each site, the regional species pool was measured. The local seed bank and the seed rain was explored to estimate the local propagule pool. Trait-based models were then applied to investigate if species traits (height, seed mass, clonal abilities, specific leaf area and dispersal method) and regional abundance influenced which species from the regional species pool, dispersed to the local community (dispersal phase) and which established (establishment phase). Filtering of species during the dispersal phase indicates the effect of seed limitation while filtering during the establishment phase indicates microsite limitation. On average 36% of the regional species pool dispersed to the local sites and of those 78% did establish. Species with enhanced dispersal abilities, e.g. higher regional abundance, smaller seeds and dispersed by cattle, were more likely to disperse to the sites than other species. At half the sites, dispersal was influenced by species height. Species establishment was however mainly unlinked to the traits included in this study. This study underlines the importance of seed limitation in local plant community assembly. It also suggests that without information on species dispersal into a site, it is difficult to distinguish between the influence of dispersal and establishment abilities, and thus seed and microsite limitation, as both can be linked to the same trait. PMID:25057815

Differential foraging preferences on seed size by rodents result in higher dispersal success of medium-sized seeds.

PubMed

Cao, Lin; Wang, Zhenyu; Yan, Chuan; Chen, Jin; Guo, Cong; Zhang, Zhibin

2016-11-01

Rodent preference for scatter-hoarding large seeds has been widely considered to favor the evolution of large seeds. Previous studies supporting this conclusion were primarily based on observations at earlier stages of seed dispersal, or on a limited sample of successfully established seedlings. Because seed dispersal comprises multiple dispersal stages, we hypothesized that differential foraging preference on seed size by animal dispersers at different dispersal stages would ultimately result in medium-sized seeds having the highest dispersal success rates. In this study, by tracking a large number of seeds for 5 yr, we investigated the effects of seed size on seed fates from seed removal to seedling establishment of a dominant plant Pittosporopsis kerrii (Icacinaceae) dispersed by scatter-hoarding rodents in tropical forest in southwest China. We found that small seeds had a lower survival rate at the early dispersal stage where more small seeds were predated at seed stations and after removal; large seeds had a lower survival rate at the late dispersal stage, more large seeds were recovered, predated after being cached, or larder-hoarded. Medium-sized seeds experienced the highest dispersal success. Our study suggests that differential foraging preferences by scatter-hoarding rodents at different stages of seed dispersal could result in conflicting selective pressures on seed size and higher dispersal success of medium-sized seeds. © 2016 by the Ecological Society of America.

A quick SEED tutorial

USGS Publications Warehouse

Ringler, Adam; Evans, John R.

2015-01-01

A number of different government-funded seismic data centers offer free open-access data (e.g., U.S. Geological Survey, National Earthquake Information Center, the Incorporated Research Institutions for Seismology (IRIS), and Data Management System), which can be freely downloaded and shared among different members of the community (Lay, 2009). To efficiently share data, it is important that different data providers follow a common format. The Standard for the Exchange of Earthquake Data (SEED) provides one such format for storing seismic and other geophysical data. The SEED format is widely used in earthquake seismology; however, SEED and its structure can be difficult for many first-time users (ourselves included). Below is a quick tutorial that outlines the basic structure of SEED format. This write-up is in no way intended to replace the comprehensive SEED manual (Ahern et al., 2009), and instead of going into the details of any specific part of the SEED format we refer the reader to the manual for additional details. The goal of this write-up is to succinctly explain the basic structure of SEED format as well as the associated jargon, as most commonly used now, in a colloquial way so that novice users of SEED can become more familiar with the format and its application quickly. Our goal is to give the reader the necessary background so that when problems or questions about SEED format arise they will have some understanding of where they should look for more details or from where the problem might be stemming. As a secondary goal, we hope to help the reader become familiar with the SEED manual (Ahern et al., 2009), which contains detailed information about all aspects of the SEED format.

Corridors cause differential seed predation.

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

Orrock, John L.; Damschen, Ellen I.

2005-06-01

Orrock, John, L., and Ellen I. Damschen. 2005. Corridors cause differential seed predation. Ecol. Apps. 15(3):793-798. Abstract. Corridors that connect disjunct populations are heavily debated in conservation, largely because the effects of corridors have rarely been evaluated by replicated, large-scale studies. Using large-scale experimental landscapes, we found that, in addition to documented positive effects, corridors also have negative impacts on bird-dispersed plants by affecting seed predation, and that overall predation is a function of the seeds primary consumer (rodents or arthropods). Both large-seeded Prunus serotina and small-seeded Rubus allegheniensis experienced greater predation in connected patches. However, P. serotina experienced significantlymore » less seed predation compared to R. allegheniensis in unconnected patches, due to decreased impacts of rodent seed predators on this large-seeded species. Viewed in light of previous evidence that corridors have beneficial impacts by increasing pollination and seed dispersal, this work demonstrates that corridors may have both positive and negative effects for the same plant species at different life stages. Moreover, these effects may differentially affect plant species within the same community: seeds primarily consumed by rodents suffer less predation in unconnected patches. By shifting the impact of rodent and arthropod seed predators, corridors constructed for plant conservation could lead to shifts in the seed bank.« less

Artificial Ripening of Sweetgum Seeds

Treesearch

F. T. Bonner

1969-01-01

Untrained collectors of hardwood seeds often start picking the seeds too early in the year. The immature seeds germinate poorly, if at all, and nursery production suffers. In the study reported here, sweetgum (Liquidambar styraciflua L.) seeds collected in central Mississippi in mid-August were ripe. Seeds collected as early as July 19 were artificially ripened by...

Excisional keratectomy combined with focal cryotherapy and amniotic membrane inlay for recalcitrant filamentary fungal keratitis: A retrospective comparative clinical data analysis

PubMed Central

Chen, Yingxin; Gao, Minghong; Duncan, Joshua K.; Ran, Di; Roe, Denise J.; Belin, Michael W.; Wang, Mingwu

2016-01-01

The aim of the present study was to investigate the efficacy of a novel surgical intervention, excisional keratectomy combined with focal cryotherapy and amniotic membrane inlay (EKCAI), for the treatment of recalcitrant filamentary fungal keratitis. A retrospective analysis was performed of patients who underwent excisional keratectomy combined with conjunctival flap inlay (EKCFI), EKCAI or therapeutic penetrating keratoplasty (TPK) from January 2006 to January 2011. Recalcitrance was determined as being unresponsive to standard medical antifungal therapy for at ≥1 week. Outcome measures among the three intervention modalities were compared. A total of 128 patients had a follow-up of ≥1 year after the primary intervention. The success rates of interventions at 1-year follow-up were 58.33% in the EKCFI group, 88.37% in the EKCAI group and 93.44% in the TPK group (P<0.0002). The preoperative visual acuity of the three groups were similar (P=0.6458), while the postoperative best-corrected visual acuity (BCVA) of patients without recurrence was significantly different among the three groups 3 months after surgery. The best postoperative BCVA was found in the TPK group, while the worst was in the EKCFI group. In conclusion, EKCAI does not require donor cornea, is straightforward surgically, and has a favorable success rate compared with EKCFI. PMID:27882109

Adaptive evolution of seed oil content in angiosperms: accounting for the global patterns of seed oils.

PubMed

Sanyal, Anushree; Decocq, Guillaume

2016-09-09

Studies of the biogeographic distribution of seed oil content in plants are fundamental to understanding the mechanisms of adaptive evolution in plants as seed oil is the primary energy source needed for germination and establishment of plants. However, seed oil content as an adaptive trait in plants is poorly understood. Here, we examine the adaptive nature of seed oil content in 168 angiosperm families occurring in different biomes across the world. We also explore the role of multiple seed traits like seed oil content and composition in plant adaptation in a phylogenetic and nonphylogenetic context. It was observed that the seed oil content in tropical plants (28.4 %) was significantly higher than the temperate plants (24.6 %). A significant relationship between oil content and latitude was observed in three families Papaveraceae, Sapindaceae and Sapotaceae indicating that selective forces correlated with latitude influence seed oil content. Evaluation of the response of seed oil content and composition to latitude and the correlation between seed oil content and composition showed that multiple seed traits, seed oil content and composition contribute towards plant adaptation. Investigation of the presence or absence of phylogenetic signals across 168 angiosperm families in 62 clades revealed that members of seven clades evolved to have high or low seed oil content independently as they did not share a common evolutionary path. The study provides us an insight into the biogeographical distribution and the adaptive role of seed oil content in plants. The study indicates that multiple seed traits like seed oil content and the fatty acid composition of the seed oils determine the fitness of the plants and validate the adaptive hypothesis that seed oil quantity and quality are crucial to plant adaptation.

Deletion of a gene cluster encoding pectin degrading enzymes in Caldicellulosiruptor bescii reveals an important role for pectin in plant biomass recalcitrance

DOE PAGES

Chung, Daehwan; Pattathil, Sivakumar; Biswal, Ajaya K.; ...

2014-10-10

A major obstacle, and perhaps the most important economic barrier to the effective use of plant biomass for the production of fuels, chemicals, and bioproducts, is our current lack of knowledge of how to efficiently and effectively deconstruct wall polymers for their subsequent use as feedstocks. Plants represent the most desired source of renewable energy and hydrocarbons because they fix CO 2, making their use carbon neutral. Their biomass structure, however, is a barrier to deconstruction, and this is often referred to as recalcitrance. Members of the bacterial genus Caldicellulosiruptor have the ability to grow on unpretreated plant biomass andmore » thus provide an assay for plant deconstruction and biomass recalcitrance. Using recently developed genetic tools for manipulation of these bacteria, a deletion of a gene cluster encoding enzymes for pectin degradation was constructed, and the resulting mutant was reduced in its ability to grow on both dicot and grass biomass, but not on soluble sugars. The plant biomass from three phylogenetically diverse plants, Arabidopsis (a herbaceous dicot), switchgrass (a monocot grass), and poplar (a woody dicot), was used in these analyses. These biomass types have cell walls that are significantly different from each other in both structure and composition. While pectin is a relatively minor component of the grass and woody dicot substrates, the reduced growth of the mutant on all three biomass types provides direct evidence that pectin plays an important role in biomass recalcitrance. Glycome profiling of the plant material remaining after growth of the mutant on Arabidopsis biomass compared to the wild-type revealed differences in the rhamnogalacturonan I, homogalacturonan, arabinogalactan, and xylan profiles. In contrast, only minor differences were observed in the glycome profiles of the switchgrass and poplar biomass. In conclusion, the combination of microbial digestion and plant biomass analysis provides a new and

Effectiveness of Extracorporeal Shock Wave Therapy Without Local Anesthesia in Patients With Recalcitrant Plantar Fasciitis: A Meta-Analysis of Randomized Controlled Trials.

PubMed

Lou, Jing; Wang, Shuai; Liu, Shuitao; Xing, Gengyan

2017-08-01

The objective of this meta-analysis was to investigate the efficacy of extracorporeal shock wave therapy in the treatment of recalcitrant plantar fasciitis without local anesthesia. The Cochrane Library, EMBASE, PubMed, and Web of Science databases were searched from inception to September 2015 for randomized controlled trials comparing ESWT without local anesthesia versus placebo for treatment of plantar fasciitis in adults. The primary outcome was the 12-week post-intervention success rate of reducing the visual analog scale score by 60% from baseline at the first step in the morning, reducing the VAS score by 60% from baseline during daily activities, reducing the Roles and Maudsley score, reducing overall heel pain, and reducing pain after applying a force meter. Nine studies were included in the meta-analysis. Compared with placebo, ESWT significantly improved the success rate of reducing overall heel pain, reducing the VAS score by 60% at the first step in the morning and during daily activities, improving the Roles and Maudsley score to excellent or good, and reducing heel pain after application of a pressure meter. ESWT seems to be particularly effective in relieving pain associated with RPF. ESWT should be considered when traditional treatments have failed. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to (1) understand the recovery rates for nonsurgical treatment of plantar fasciitis, (2) understand the role of extracorporeal shockwave therapy (ESWT) in the treatment of recalcitrant plantar fasciitis, and (3) understand the indications to incorporate ESWT in the treatment plan of recalcitrant plantar fasciitis. Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of

Buried Seed Banks as Indicators of Seed Output along an Altitudinal Gradient.

ERIC Educational Resources Information Center

Thompson, K.

1985-01-01

Study of buried seed banks (viable seeds deposited in the soil near parent plants) provides a relatively easy way of determining cumulative effects on seed production and species' altitudinal limits. Sites, methods, validity, interpretation, problems of collection on a mountain, and germination techniques are discussed. (Author/DH)

Seed Anatomy and Water Uptake in Relation to Seed Dormancy in Opuntia tomentosa (Cactaceae, Opuntioideae)

PubMed Central

Orozco-Segovia, A.; Márquez-Guzmán, J.; Sánchez-Coronado, M. E.; Gamboa de Buen, A.; Baskin, J. M.; Baskin, C. C.

2007-01-01

Background and Aims There is considerable confusion in the literature concerning impermeability of seeds with ‘hard’ seed coats, because the ability to take up (imbibe) water has not been tested in most of them. Seeds of Opuntia tomentosa were reported recently to have a water-impermeable seed coat sensu lato (i.e. physical dormancy), in combination with physiological dormancy. However, physical dormancy is not known to occur in Cactaceae. Therefore, the aim of this study was to determine if seeds of O. tomentosa are water-permeable or water-impermeable, i.e. if they have physical dormancy. Methods The micromorphology of the seed coat and associated structures were characterized by SEM and light microscopy. Permeability of the seed-covering layers was assessed by an increase in mass of seeds on a wet substrate and by dye-tracking and uptake of tritiated water by intact versus scarified seeds. Key Results A germination valve and a water channel are formed in the hilum–micropyle region during dehydration and ageing in seeds of O. tomentosa. The funicular envelope undoubtedly plays a role in germination of Opuntia seeds via restriction of water uptake and mechanical resistance to expansion of the embryo. However, seeds do not exhibit any of three features characteristic of those with physical dormancy. Thus, they do not have a water-impermeable layer(s) of palisade cells (macrosclereids) or a water gap sensu stricto and they imbibe water without the seed coat being disrupted. Conclusions Although dormancy in seeds of this species can be broken by scarification, they have physiological dormancy only. Further, based on information in the literature, it is concluded that it is unlikely that any species of Opuntia has physical dormancy. This is the first integrative study of the anatomy, dynamics of water uptake and dormancy in seeds of Cactaceae subfamily Opuntioideae. PMID:17298989

Healthy food trends -- chia seeds

MedlinePlus

... Healthy snacks - Chia seeds; Weight loss - Chia seeds; Healthy diet - Chia seeds; Wellness - Chia seeds ... of nutrition and dietetics: dietary fatty acids for healthy adults. J Acad Nutr Diet . 2014;114(1):136-153. PMID: 24342605 www. ...

Seed deposition patterns and the survival of seeds and seedlings of the palm Euterpe edulis

NASA Astrophysics Data System (ADS)

Pizo, Marco A.; Simão, Isaac

2001-08-01

The seed deposition pattern created by a seed disperser is one of the components of the efficiency of a species as seed disperser, and ultimately may influence the recruitment of a plant species. In this study, we used the seeds of a bird-dispersed forest palm, Euterpe edulis, to investigate the effects of two distinct seed deposition patterns created by birds that defecate (clumped pattern) and regurgitate seeds (loose-clumped pattern) on the survival of seeds experimentally set in an E. edulis-rich site, and of seedlings grown under shade-house conditions. The study was conducted in the lowland forest of Parque Estadual Intervales, SE Brazil. Clumped and loose-clumped seeds were equally preyed upon by rodents and insects. Although clumped and isolated seedlings had the same root weight after 1 year, the isolated seedlings survived better and presented more developed shoots, suggesting intraspecific competition among clumped seedlings. Our results indicate that animals that deposit E. edulis seeds in faecal clumps (e.g. cracids, tapirs) are less efficient seed dispersers than those that regurgitate seeds individually (e.g. trogons, toucans). Intraspecific competition among seedlings growing from faecal clumps is a likely process preventing the occurrence of clumps of adult palms.

A Prospective Quasi-Randomized Comparison of Intraoperatively Built Custom-Linked Seeds Versus Loose Seeds for Prostate Brachytherapy

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

Ishiyama, Hiromichi, E-mail: hishiyam@kitasato-u.ac.jp; Satoh, Takefumi; Kawakami, Shogo

Purpose: To compare dosimetric parameters, seed migration rates, operation times, and acute toxicities of intraoperatively built custom-linked (IBCL) seeds with those of loose seeds for prostate brachytherapy. Methods and Materials: Participants were 140 patients with low or intermediate prostate cancer prospectively allocated to an IBCL seed group (n=74) or a loose seed group (n=66), using quasirandomization (allocated by week of the month). All patients underwent prostate brachytherapy using an interactive plan technique. Computed tomography and plain radiography were performed the next day and 1 month after brachytherapy. The primary endpoint was detection of a 5% difference in dose to 90% ofmore » prostate volume on postimplant computed tomography 1 month after treatment. Seed migration was defined as a seed position >1 cm from the cluster of other seeds on radiography. A seed dropped into the seminal vesicle was also defined as a migrated seed. Results: Dosimetric parameters including the primary endpoint did not differ significantly between groups, but seed migration rate was significantly lower in the IBCL seed group (0%) than in the loose seed group (55%; P<.001). Mean operation time was slightly but significantly longer in the IBCL seed group (57 min) than in the loose seed group (50 min; P<.001). No significant differences in acute toxicities were seen between groups (median follow-up, 9 months). Conclusions: This prospective quasirandomized control trial showed no dosimetric differences between IBCL seed and loose seed groups. However, a strong trend toward decreased postimplant seed migration was shown in the IBCL seed group.« less

Tree-to-tree variation in seed size and its consequences for seed dispersal versus predation by rodents.

PubMed

Wang, Bo; Ives, Anthony R

2017-03-01

Individual variation in seed size and seed production is high in many plant species. How does this variation affect seed-dispersing animals and, in turn, the fitness of individual plants? In this study, we first surveyed intraspecific variation in seed mass and production in a population of a Chinese white pine, Pinus armandii. For 134 target trees investigated in 2012, there was very high variation in seed size, with mean seed mass varying among trees almost tenfold, from 0.038 to 0.361 g. Furthermore, 30 of the 134 trees produced seeds 2 years later, and for these individuals there was a correlation in seed mass of 0.59 between years, implying consistent differences among individuals. For a subset of 67 trees, we monitored the foraging preferences of scatter-hoarding rodents on a total of 15,301 seeds: 8380 were ignored, 3184 were eaten in situ, 2651 were eaten after being cached, and 395 were successfully dispersed (cached and left intact). At the scale of individual seeds, seed mass affected almost every decision that rodents made to eat, remove, and cache individual seeds. At the level of individual trees, larger seeds had increased probabilities of both predation and successful dispersal: the effects of mean seed size on costs (predation) and benefits (caching) balanced out. Thus, despite seed size affecting rodent decisions, variation among trees in dispersal success associated with mean seed size was small once seeds were harvested. This might explain, at least in part, the maintenance of high variation in mean seed mass among tree individuals.

Seed wasp invasions promoted by unregulated seed trade affect vegetal and animal biodiversity.

PubMed

Auger-Rozenberg, Marie-Anne; Roques, Alain

2012-09-01

Cone and seed insects are considered the most important predators of tree seeds during the pre-dispersal phase of development. Among them, exotic seed chalcids in the genus Megastigmus invaded Europe as a result of the rapidly-increasing and mostly unregulated seed trade for afforestation and ornamental plantations. Unlike their economic impact in seed orchards, until recently, little attention was paid to the ecological impact of these insects. In the present study, selected case studies of alien Megastigmus spp. were considered to assess their specific impact on the potential of natural regeneration of native woody plants and on the native entomofauna competing for seed resource. We re-analyzed data from former studies that did not focus on these ecological interactions and, here, present previously unpublished results. Seeds of Douglas-fir, true cedars, true firs and wild roses were sampled all over Europe, and the relative importance of the native and invasive chalcid species was assessed as well as their specific impact on seed yield. In most cases, the recent arrival of alien chalcids resulted in a significant decrease in the regeneration potential of the host trees. In the absence of competitors, alien chalcids occupied the entire seed niche in Douglas-fir, but their impact tended to decrease after the arrival of invasive seed bugs. In firs, alien chalcids tended to displace the native chalcids, but not in wild roses and cedars, where their damage was increasing. Different biological traits that might explain invasive success of alien chalcids are discussed. However, no general invasive patterns seem to exist. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Seed tolerance to predation: Evidence from the toxic seeds of the buckeye tree (Aesculus californica; Sapindaceae).

PubMed

Mendoza, Eduardo; Dirzo, Rodolfo

2009-07-01

Tolerance, the capacity of plants to withstand attack by animals, as opposed to resistance, has been poorly examined in the context of seed predation. We investigated the role that the seed mass of the large-seeded endemic tree Aesculus californica plays as a tolerance trait to rodent attack by comparing, under greenhouse conditions, patterns of germination, and subsequent seedling growth, of seeds with a wide range of natural damage. Germination percentage was reduced by 50% and time to germination by 64% in attacked compared to intact seeds, and germination probability was negatively correlated with damage. Seedlings that emerged from intact seeds were taller and bore more leaves than those from damaged seeds. This species' large seed mass favors tolerance to damage because heavily damaged seeds are able to germinate and produce seedlings. This finding is significant given that seeds of this species are known to contain chemical compounds toxic to vertebrates, a resistance trait. We posit that this combination of tolerance and resistance traits might be a particularly effective antipredation strategy when seeds are exposed to a variety of vertebrate predators.

Dissecting the proteome of pea mature seeds reveals the phenotypic plasticity of seed protein composition.

PubMed

Bourgeois, Michael; Jacquin, Françoise; Savois, Vincent; Sommerer, Nicolas; Labas, Valérie; Henry, Céline; Burstin, Judith

2009-01-01

Pea (Pisum sativum L.) is the most cultivated European pulse crop and the pea seeds mainly serve as a protein source for monogastric animals. Because the seed protein composition impacts on seed nutritional value, we aimed at identifying the determinants of its variability. This paper presents the first pea mature seed proteome reference map, which includes 156 identified proteins (http://www.inra.fr/legumbase/peaseedmap/). This map provides a fine dissection of the pea seed storage protein composition revealing a large diversity of storage proteins resulting both from gene diversity and post-translational processing. It gives new insights into the pea storage protein processing (especially 7S globulins) as a possible adaptation towards progressive mobilization of the proteins during germination. The nonstorage seed proteome revealed the presence of proteins involved in seed defense together with proteins preparing germination. The plasticity of the seed proteome was revealed for seeds produced in three successive years of cultivation, and 30% of the spots were affected by environmental variations. This work pinpoints seed proteins most affected by environment, highlighting new targets to stabilize storage protein composition that should be further analyzed.

Small-seeded Hakea species tolerate cotyledon loss better than large-seeded congeners

PubMed Central

El-Amhir, Sh-hoob; Lamont, Byron B.; He, Tianhua; Yan, George

2017-01-01

Six Hakea species varying greatly in seed size were selected for cotyledon damage experiments. The growth of seedlings with cotyledons partially or completely removed was monitored over 90 days. All seedlings perished by the fifth week when both cotyledons were removed irrespective of seed size. Partial removal of cotyledons caused a significant delay in the emergence of the first leaf, and reduction in root and shoot growth of the large-seeded species. The growth of seedlings of small-seeded species was less impacted by cotyledon damage. The rate of survival, root and shoot lengths and dry biomass of the seedlings were determined after 90 days. When seedlings were treated with balanced nutrient solutions following removal of the cotyledons, survival was 95–98%, but 0% when supplied with nutrient solutions lacking N or P or with water only. The addition of a balanced nutrient solution failed to restore complete growth of any species, but the rate of root elongation for the small-seeded species was maintained. Cotyledons provide nutrients to support early growth of Hakea seedlings, but other physiological roles for the cotyledons are also implicated. In conclusion, small-seeded Hakea species can tolerate cotyledons loss better than large-seeded species. PMID:28139668

Can a botanic garden cycad collection capture the genetic diversity in a wild population?

USDA-ARS?s Scientific Manuscript database

Conservation of plant species often requires ex situ (off-site) cultivation of living collections. Cycads constitute the most imperiled major group of plants, and ex situ collections are an important part of conservation planning for this group, given seed recalcitrance, difficulties with tissue cul...

Slide Esophagoplasty vs End-to-End Anastomosis for Recalcitrant Esophageal Stricture after Esophageal Atresia Repair.

PubMed

Kamran, Ali; Smithers, Charles J; Manfredi, Michael A; Hamilton, Thomas E; Ngo, Peter D; Zurakowski, David; Jennings, Russell W

2018-06-01

Anastomotic stricture is a common complication after esophageal atresia (EA) repair. Patients with a recalcitrant stricture may require surgical intervention. The technique of reanastomosis after stricture resection can affect patient outcomes. Patients with EA who underwent anastomotic stricture resection, from July 2010 to February 2017, were reviewed. After stricture resection, patients who had slide esophagoplasty performed were compared with those having conventional end-to-end anastomosis. Fifty patients underwent stricture repair surgery by slide esophagoplasty (n = 12) or end-to-end (n = 38) anastomosis technique at a median age of 14 months (interquartile range [IQR] 6 to 23 months). Significantly fewer patients required dilation therapy after slide esophagoplasty: 6 of 12 (50%) compared with 32 of 38 (84%) in the end-to-end group (p = 0.02). The number of dilation sessions was significantly lower in the slide group vs the end-to-end (p = 0.004) group, with a risk ratio confirming the approximately half the number of dilations for the slide approach (risk ratio 0.57, 95% CI 0.38 to 0.86). Steroid injection was combined with dilation in 3 of 12 (25%) vs 22 of 38 (58%) in the slide and end-to-end groups, respectively (p = 0.10). Stent placement was used in none of slide cases vs 8 of 38 (21%) in the end-to-end group (p = 0.17). Stricture incision was performed in 1 of 12 (8%) in the slide group and 11 of 38 (29%) in the end-to-end group (p = 0.25). There were leak complications in fewer patients after slide esophagoplasty compared with end-to-end anastomosis: 1 of 12 (8%) vs 8 of 38 (21%) (p = 0.43). Slide esophagoplasty may be a useful technique of anastomotic configuration for selected patients with recalcitrant esophageal stricture, offering more favorable outcomes compared with end-to-end anastomosis. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Methodological bias in the seed bank flora holds significant implications for understanding seed bank community functions.

PubMed

Plue, J; Colas, F; Auffret, A G; Cousins, S A O

2017-03-01

Persistent seed banks are a key plant regeneration strategy, buffering environmental variation to allow population and species persistence. Understanding seed bank functioning within herb layer dynamics is therefore important. However, rather than assessing emergence from the seed bank in herb layer gaps, most studies evaluate the seed bank functioning via a greenhouse census. We hypothesise that greenhouse data may not reflect seed bank-driven emergence in disturbance gaps due to methodological differences. Failure in detecting (specialist) species may then introduce methodological bias into the ecological interpretation of seed bank functions using greenhouse data. The persistent seed bank was surveyed in 40 semi-natural grassland plots across a fragmented landscape, quantifying seedling emergence in both the greenhouse and in disturbance gaps. Given the suspected interpretational bias, we tested whether each census uncovers similar seed bank responses to fragmentation. Seed bank characteristics were similar between censuses. Census type affected seed bank composition, with >25% of species retrieved better by either census type, dependent on functional traits including seed longevity, production and size. Habitat specialists emerged more in disturbance gaps than in the greenhouse, while the opposite was true for ruderal species. Both censuses uncovered fragmentation-induced seed bank patterns. Low surface area sampling, larger depth of sampling and germination conditions cause underrepresentation of the habitat-specialised part of the persistent seed bank flora during greenhouse censuses. Methodological bias introduced in the recorded seed bank data may consequently have significant implications for the ecological interpretation of seed bank community functions based on greenhouse data. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Seed Dispersers, Seed Predators, and Browsers Act Synergistically as Biotic Filters in a Mosaic Landscape

PubMed Central

Zamora, Regino; Matías, Luis

2014-01-01

In this study, we analize the functional influence of animals on the plants they interact with in a mediterranean mountain. We hypothesise that seed dispersers, seed predators, and browsers can act as biotic filters for plant communities. We analyse the combined effects of mutualistic (seed dispersal) and antagonistic (seed predation, herbivory) animal interactions in a mosaic landscape of Mediterranean mountains, basing our results on observational and experimental field. Most of the dispersed seeds came from tree species, whereas the population of saplings was composed predominantly of zoochorous shrub species. Seed predators preferentially consumed seeds from tree species, whereas seeds from the dominant fleshy-fruited shrubs had a higher probability of escaping these predators. The same pattern was repeated among the different landscape units by browsers, since they browsed selectively and far more intensely on tree-species saplings than on the surrounding shrubs. In synthesis, our work identifies the major biotic processes that appear to be favoring a community dominated by shrubs versus trees because seed dispersers, predators, and herbivores together favored shrub dispersal and establishment versus trees. PMID:25233342

Global Changes in DNA Methylation in Seeds and Seedlings of Pyrus communis after Seed Desiccation and Storage

PubMed Central

Michalak, Marcin; Barciszewska, Mirosława Z.; Barciszewski, Jan; Plitta, Beata P.; Chmielarz, Paweł

2013-01-01

The effects of storage and deep desiccation on structural changes of DNA in orthodox seeds are poorly characterized. In this study we analyzed the 5-methylcytosine (m5C) global content of DNA isolated from seeds of common pear (Pyrus communis L.) that had been subjected to extreme desiccation, and the seedlings derived from these seeds. Germination and seedling emergence tests were applied to determine seed viability after their desiccation. In parallel, analysis of the global content of m5C in dried seeds and DNA of seedlings obtained from such seeds was performed with a 2D TLC method. Desiccation of fresh seeds to 5.3% moisture content (mc) resulted in a slight reduction of DNA methylation, whereas severe desiccation down to 2–3% mc increased DNA methylation. Strong desiccation of seeds resulted in the subsequent generation of seedlings of shorter height. A 1-year period of seed storage induced a significant increase in the level of DNA methylation in seeds. It is possible that alterations in the m5C content of DNA in strongly desiccated pear seeds reflect a reaction of desiccation-tolerant (orthodox) seeds to severe desiccation. Epigenetic changes were observed not only in severely desiccated seeds but also in 3-month old seedlings obtained from these seeds. With regard to seed storage practices, epigenetic assessment could be used by gene banks for early detection of structural changes in the DNA of stored seeds. PMID:23940629

Gender inequality in predispersal seed predation contributes to female seed set advantage in a gynodioecious species.

PubMed

Clarke, Gretel L; Brody, Alison K

2015-05-01

Most flowering plants are hermaphrodites. However, in gynodioecious species, some members of the population are male-sterile and reproduce only by setting seed, while others gain fitness through both male and female function. How females compensate for the loss of male function remains unresolved for most gynodioecious species. Here, as with many plants, fitness differences may be influenced by interactions with multiple species. However, whether multiple species interactions result in gender-specific fitness differences remains unknown. Using observational data from 2009-2010, we quantified seed set of the two sex morphs of Polemonium foliosissimu and asked how it is affected by pollination, and seed predation from a dipteran predispersal seed predator (Anthomyiidae: Hylemya sp.). We assessed seed production and losses to predation in 27 populations for one year and in six populations for a second year. Females set significantly more seed than did hermaphrodites in both years. Of the fitness components we assessed, including the number of flowers per plant, fruit set, seeds/fruit, and proportion of fruits destroyed by Hylemya, only fruit destruction differed significantly between the sexes. In one year, seeds/fruit and predation had a stronger effect on seed set for hermaphrodites than for females. Because predispersal seed predators do not pollinate flowers, their effects may depend on successful pollination of flowers on which they oviposit. To examine if genders differed in pollen limitation and seed predation and/or their interactive effects, in 2011 we hand-pollinated flowers and removed seed predator eggs in a fully factorial design. Both sexes were pollen limited, but their degree of pollen limitation did not differ. However, predation reduced.seed set more for hermaphrodites than for females. We found no significant interaction between hand pollen and seed predation, and no interaction between hand pollination and gender. Our results suggest that while

Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: Where do all the seeds go?

USGS Publications Warehouse

DeFalco, L.A.; Esque, T.C.; Nicklas, M.B.; Kane, J.M.

2012-01-01

Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert-sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application. ?? 2010 Society for Ecological Restoration International.

Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: where do all the seeds go?

USGS Publications Warehouse

DeFalco, Lesley A.; Esque, Todd C.; Nicklas, Melissa B.; Kane, Jeffrey M.

2012-01-01

Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert—sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application.

Occurrence of trends of weed seed and pathogen contaminants in bentgrass seed lots in Oregon

USDA-ARS?s Scientific Manuscript database

Nearly all of the bentgrass seed grown in the United States is produced in Oregon. However, little is known about the occurrence of weed seed or pathogen propagule contaminants in bentgrass seed lots. This study was conducted to assess the diversity and frequency of occurrence of weed seeds, ergot (...

The Seed Semipermeable Layer and Its Relation to Seed Quality Assessment in Four Grass Species.

PubMed

Lv, Yan Y; He, Xue Q; Hu, Xiao W; Wang, Yan R

2017-01-01

The existence of a semipermeable layer in grass seeds has been extensively reported, yet knowledge of its influence on tests for seed viability and vigor that depend upon measurement of electrical conductivity (EC) is limited. This study determined the presence and location of the semipermeable layer, and its relation to seed viability and vigor assessment, in seeds of four important grass species- Elymus nutans Griseb., Lolium perenne L., Leymus chinensis (Trin.) Tzvel., and Avena sativa L. Intact seeds of E. nutans, Lolium perenne , and Leymus chinensis exhibited little staining with triphenyl tetrazolium chloride (TTC), and there were no differences in EC between seeds with different germination percentage (GP) ( P > 0.05). After piercing the seed coat, however, all three species displayed positive staining with TTC, along with a significant negative correlation between EC and GP ( E. nutans : R 2 = 0.7708; Lolium perenne : R 2 = 0.8414; Leymus chinensis : R 2 = 0.859; P < 0.01). In contrast, both intact and pierced seeds of A. sativa possessed a permeable seed coat that showed positive staining with TTC and EC values that were significantly negatively correlated with GP [ R 2 = 0.9071 (intact) and 0.9597 (pierced); P < 0.01]. In commercial seed lots of A. sativa , a field emergence test indicated that EC showed a significant negative correlation with field emergence at two sowing dates ( R 2 = 0.6069, P < 0.01 and 0.5316, P < 0.05). Analysis of seed coat permeability revealed the presence of a semipermeable layer located in the seed coat adjacent to the endosperm in E. nutans, Lolium perenne , and Leymus chinensis ; however, no semipermeable layer was observed in A. sativa. This is the first report of the absence of a semipermeable layer in a grass species. The existence of a semipermeable layer is one of the most important factors affecting seed viability and vigor testing (based on EC measurement) in E. nutans, Lolium perenne , and Leymus chinensis

Effect of GA3 treatment on seed development and seed-related gene expression in grape.

PubMed

Cheng, Chenxia; Xu, Xiaozhao; Singer, Stacy D; Li, Jun; Zhang, Hongjing; Gao, Min; Wang, Li; Song, Junyang; Wang, Xiping

2013-01-01

The phytohormone gibberellic acid (GA3) is widely used in the table grape industry to induce seedlessness in seeded varieties. However, there is a paucity of information concerning the mechanisms by which GAs induce seedlessness in grapes. In an effort to systematically analyze the cause of this GA3-induced seed abortion, we conducted an in depth characterization of two seeded grape cultivars ('Kyoho' and 'Red Globe'), along with a seedless cultivar ('Thompson Seedless'), following treatment with GA3. In a similar fashion to the seedless control, which exhibited GA3-induced abortion of the seeds 9 days after full bloom (DAF), both 'Kyoho' and 'Red Globe' seeded varieties exhibited complete abortion of the seeds 15 DAF when treated with GA3. Morphological analyses indicated that while fertilization appeared to occur normally following GA3 treatment, as well as in the untreated seedless control cultivar, seed growth eventually ceased. In addition, we found that GA3 application had an effect on redox homeostasis, which could potentially cause cell damage and subsequent seed abortion. Furthermore, we carried out an analysis of antioxidant enzyme activities, as well as transcript levels from various genes believed to be involved in seed development, and found several differences between GA3-treated and untreated controls. Therefore, it seems that the mechanisms driving GA3-induced seedlessness are similar in both seeded and seedless cultivars, and that the observed abortion of seeds may result at least in part from a GA3-induced increase in cell damage caused by reactive oxygen species, a decrease in antioxidant enzymatic activities, and an alteration of the expression of genes related to seed development.

Seed dimorphism, nutrients and salinity differentially affect seed traits of the desert halophyte Suaeda aralocaspica via multiple maternal effects.

PubMed

Wang, Lei; Baskin, Jerry M; Baskin, Carol C; Cornelissen, J Hans C; Dong, Ming; Huang, Zhenying

2012-09-25

Maternal effects may influence a range of seed traits simultaneously and are likely to be context-dependent. Disentangling the interactions of plant phenotype and growth environment on various seed traits is important for understanding regeneration and establishment of species in natural environments. Here, we used the seed-dimorphic plant Suaeda aralocaspica to test the hypothesis that seed traits are regulated by multiple maternal effects. Plants grown from brown seeds had a higher brown:black seed ratio than plants from black seeds, and germination percentage of brown seeds was higher than that of black seeds under all conditions tested. However, the coefficient of variation (CV) for size of black seeds was higher than that of brown seeds. Seeds had the smallest CV at low nutrient and high salinity for plants from brown seeds and at low nutrient and low salinity for plants from black seeds. Low levels of nutrients increased size and germinability of black seeds but did not change the seed morph ratio or size and germinability of brown seeds. High levels of salinity decreased seed size but did not change the seed morph ratio. Seeds from high-salinity maternal plants had a higher germination percentage regardless of level of germination salinity. Our study supports the multiple maternal effects hypothesis. Seed dimorphism, nutrient and salinity interacted in determining a range of seed traits of S. aralocaspica via bet-hedging and anticipatory maternal effects. This study highlights the importance of examining different maternal factors and various offspring traits in studies that estimate maternal effects on regeneration.

Seed dimorphism, nutrients and salinity differentially affect seed traits of the desert halophyte Suaeda aralocaspica via multiple maternal effects

PubMed Central

2012-01-01

Background Maternal effects may influence a range of seed traits simultaneously and are likely to be context-dependent. Disentangling the interactions of plant phenotype and growth environment on various seed traits is important for understanding regeneration and establishment of species in natural environments. Here, we used the seed-dimorphic plant Suaeda aralocaspica to test the hypothesis that seed traits are regulated by multiple maternal effects. Results Plants grown from brown seeds had a higher brown:black seed ratio than plants from black seeds, and germination percentage of brown seeds was higher than that of black seeds under all conditions tested. However, the coefficient of variation (CV) for size of black seeds was higher than that of brown seeds. Seeds had the smallest CV at low nutrient and high salinity for plants from brown seeds and at low nutrient and low salinity for plants from black seeds. Low levels of nutrients increased size and germinability of black seeds but did not change the seed morph ratio or size and germinability of brown seeds. High levels of salinity decreased seed size but did not change the seed morph ratio. Seeds from high-salinity maternal plants had a higher germination percentage regardless of level of germination salinity. Conclusions Our study supports the multiple maternal effects hypothesis. Seed dimorphism, nutrient and salinity interacted in determining a range of seed traits of S. aralocaspica via bet-hedging and anticipatory maternal effects. This study highlights the importance of examining different maternal factors and various offspring traits in studies that estimate maternal effects on regeneration. PMID:23006315

Extension of oil biosynthesis during the mid-phase of seed development enhances oil content in Arabidopsis seeds.

PubMed

Kanai, Masatake; Mano, Shoji; Kondo, Maki; Hayashi, Makoto; Nishimura, Mikio

2016-05-01

Regulation of oil biosynthesis in plant seeds has been extensively studied, and biotechnological approaches have been designed to increase seed oil content. Oil and protein synthesis is negatively correlated in seeds, but the mechanisms controlling interactions between these two pathways are unknown. Here, we identify the molecular mechanism controlling oil and protein content in seeds. We utilized transgenic Arabidopsis thaliana plants overexpressing WRINKLED1 (WRI1), a master transcription factor regulating seed oil biosynthesis, and knockout mutants of major seed storage proteins. Oil and protein biosynthesis in wild-type plants was sequentially activated during early and late seed development, respectively. The negative correlation between oil and protein contents in seeds arises from competition between the pathways. Extension of WRI1 expression during mid-phase of seed development significantly enhanced seed oil content. This study demonstrates that temporal activation of genes involved in oil or storage protein biosynthesis determines the oil/protein ratio in Arabidopsis seeds. These results provide novel insights into potential breeding strategies to generate crops with high oil contents in seeds. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Gravity independence of seed-to-seed cycling in Brassica rapa

NASA Technical Reports Server (NTRS)

Musgrave, M. E.; Kuang, A.; Xiao, Y.; Stout, S. C.; Bingham, G. E.; Briarty, L. G.; Levenskikh, M. A.; Sychev, V. N.; Podolski, I. G.

2000-01-01

Growth of higher plants in the microgravity environment of orbital platforms has been problematic. Plants typically developed more slowly in space and often failed at the reproductive phase. Short-duration experiments on the Space Shuttle showed that early stages in the reproductive process could occur normally in microgravity, so we sought a long-duration opportunity to test gravity's role throughout the complete life cycle. During a 122-d opportunity on the Mir space station, full life cycles were completed in microgravity with Brassica rapa L. in a series of three experiments in the Svet greenhouse. Plant material was preserved in space by chemical fixation, freezing, and drying, and then compared to material preserved in the same way during a high-fidelity ground control. At sampling times 13 d after planting, plants on Mir were the same size and had the same number of flower buds as ground control plants. Following hand-pollination of the flowers by the astronaut, siliques formed. In microgravity, siliques ripened basipetally and contained smaller seeds with less than 20% of the cotyledon cells found in the seeds harvested from the ground control. Cytochemical localization of storage reserves in the mature embryos showed that starch was retained in the spaceflight material, whereas protein and lipid were the primary storage reserves in the ground control seeds. While these successful seed-to-seed cycles show that gravity is not absolutely required for any step in the plant life cycle, seed quality in Brassica is compromised by development in microgravity.

Microseed matrix screening for optimization in protein crystallization: what have we learned?

PubMed

D'Arcy, Allan; Bergfors, Terese; Cowan-Jacob, Sandra W; Marsh, May

2014-09-01

Protein crystals obtained in initial screens typically require optimization before they are of X-ray diffraction quality. Seeding is one such optimization method. In classical seeding experiments, the seed crystals are put into new, albeit similar, conditions. The past decade has seen the emergence of an alternative seeding strategy: microseed matrix screening (MMS). In this strategy, the seed crystals are transferred into conditions unrelated to the seed source. Examples of MMS applications from in-house projects and the literature include the generation of multiple crystal forms and different space groups, better diffracting crystals and crystallization of previously uncrystallizable targets. MMS can be implemented robotically, making it a viable option for drug-discovery programs. In conclusion, MMS is a simple, time- and cost-efficient optimization method that is applicable to many recalcitrant crystallization problems.

Microseed matrix screening for optimization in protein crystallization: what have we learned?

PubMed Central

D’Arcy, Allan; Bergfors, Terese; Cowan-Jacob, Sandra W.; Marsh, May

2014-01-01

Protein crystals obtained in initial screens typically require optimization before they are of X-ray diffraction quality. Seeding is one such optimization method. In classical seeding experiments, the seed crystals are put into new, albeit similar, conditions. The past decade has seen the emergence of an alternative seeding strategy: microseed matrix screening (MMS). In this strategy, the seed crystals are transferred into conditions unrelated to the seed source. Examples of MMS applications from in-house projects and the literature include the generation of multiple crystal forms and different space groups, better diffracting crystals and crystallization of previously uncrystallizable targets. MMS can be implemented robotically, making it a viable option for drug-discovery programs. In conclusion, MMS is a simple, time- and cost-efficient optimization method that is applicable to many recalcitrant crystallization problems. PMID:25195878

Effects of treatment and seed source on germination of eastern redcedar seed

Treesearch

David F. Van Haverbeke; C. W. Comer

1985-01-01

Germination of eastern redcedar (Juniperus virginiana L.) seeds was best with a 96-hour soak in citric acid (10,000 ppm), with 6 weeks of moist-warm (24° C) stratification, and 10 weeks of moist-cold (5° C) stratification. Geographic seed sources responded differently to treatment. Use of fresh seeds could reduce the time in moist-warm stratification, would improve...

Poor Fertility, Short Longevity, and Low Abundance in the Soil Seed Bank Limit Volunteer Sugarcane from Seed

PubMed Central

Pierre, Johann S.; Perroux, Jai; Whan, Alex; Rae, Anne L.; Bonnett, Graham D.

2015-01-01

The recent development of genetically modified sugarcane, with the aim of commercial production, requires an understanding of the potential risks of increased weediness of sugarcane as a result of spread and persistence of volunteer sugarcane. As sugarcane is propagated vegetatively from pieces of stalk and the seed plays no part in the production cycle, the fate of seed in the environment is yet to be studied. In this study, sugarcane seed samples, collected in fields over a 2-year period, were used to determine the overall level of sugarcane fertility, seed dormancy, and longevity of seed under field conditions. A survey of the soil seed bank in and around sugarcane fields was used to quantify the presence of sugarcane seeds and to identify and quantify the weeds that would compete with sugarcane seedlings. We demonstrated that under field conditions, sugarcane has low fertility and produces non-dormant seed. The viability of the seeds decayed rapidly (half-life between 1.5 and 2.1 months). This means that, in Australia, sugarcane seeds die before they encounter climatic conditions that could allow them to germinate and establish. Finally, the soil seed bank analysis revealed that there were very few sugarcane seeds relative to the large number of weed seeds that exert a large competitive effect. In conclusion, low fertility, short persistence, and poor ability to compete limit the capacity of sugarcane seed spread and persistence in the environment. PMID:26090363

Poor Fertility, Short Longevity, and Low Abundance in the Soil Seed Bank Limit Volunteer Sugarcane from Seed.

PubMed

Pierre, Johann S; Perroux, Jai; Whan, Alex; Rae, Anne L; Bonnett, Graham D

2015-01-01

The recent development of genetically modified sugarcane, with the aim of commercial production, requires an understanding of the potential risks of increased weediness of sugarcane as a result of spread and persistence of volunteer sugarcane. As sugarcane is propagated vegetatively from pieces of stalk and the seed plays no part in the production cycle, the fate of seed in the environment is yet to be studied. In this study, sugarcane seed samples, collected in fields over a 2-year period, were used to determine the overall level of sugarcane fertility, seed dormancy, and longevity of seed under field conditions. A survey of the soil seed bank in and around sugarcane fields was used to quantify the presence of sugarcane seeds and to identify and quantify the weeds that would compete with sugarcane seedlings. We demonstrated that under field conditions, sugarcane has low fertility and produces non-dormant seed. The viability of the seeds decayed rapidly (half-life between 1.5 and 2.1 months). This means that, in Australia, sugarcane seeds die before they encounter climatic conditions that could allow them to germinate and establish. Finally, the soil seed bank analysis revealed that there were very few sugarcane seeds relative to the large number of weed seeds that exert a large competitive effect. In conclusion, low fertility, short persistence, and poor ability to compete limit the capacity of sugarcane seed spread and persistence in the environment.

Tracking Seed Fates of Tropical Tree Species: Evidence for Seed Caching in a Tropical Forest in North-East India

PubMed Central

Sidhu, Swati; Datta, Aparajita

2015-01-01

Rodents affect the post-dispersal fate of seeds by acting either as on-site seed predators or as secondary dispersers when they scatter-hoard seeds. The tropical forests of north-east India harbour a high diversity of little-studied terrestrial murid and hystricid rodents. We examined the role played by these rodents in determining the seed fates of tropical evergreen tree species in a forest site in north-east India. We selected ten tree species (3 mammal-dispersed and 7 bird-dispersed) that varied in seed size and followed the fates of 10,777 tagged seeds. We used camera traps to determine the identity of rodent visitors, visitation rates and their seed-handling behavior. Seeds of all tree species were handled by at least one rodent taxon. Overall rates of seed removal (44.5%) were much higher than direct on-site seed predation (9.9%), but seed-handling behavior differed between the terrestrial rodent groups: two species of murid rodents removed and cached seeds, and two species of porcupines were on-site seed predators. In addition, a true cricket, Brachytrupes sp., cached seeds of three species underground. We found 309 caches formed by the rodents and the cricket; most were single-seeded (79%) and seeds were moved up to 19 m. Over 40% of seeds were re-cached from primary cache locations, while about 12% germinated in the primary caches. Seed removal rates varied widely amongst tree species, from 3% in Beilschmiedia assamica to 97% in Actinodaphne obovata. Seed predation was observed in nine species. Chisocheton cumingianus (57%) and Prunus ceylanica (25%) had moderate levels of seed predation while the remaining species had less than 10% seed predation. We hypothesized that seed traits that provide information on resource quantity would influence rodent choice of a seed, while traits that determine resource accessibility would influence whether seeds are removed or eaten. Removal rates significantly decreased (p < 0.001) while predation rates increased (p = 0

Nest-mediated seed dispersal

Treesearch

Robert J. Warren; Jason P. Love; Mark A. Bradford

2017-01-01

Many plant seeds travel on the wind and through animal ingestion or adhesion; however, an overlooked dispersal mode may lurk within those dispersal modes. Viable seeds may remain attached or embedded within materials birds gather for nest building. Our objective was to determine if birds inadvertently transport seeds when they forage for plant materials to...

Effect of GA3 Treatment on Seed Development and Seed-Related Gene Expression in Grape

PubMed Central

Cheng, Chenxia; Xu, Xiaozhao; Singer, Stacy D.; Li, Jun; Zhang, Hongjing; Gao, Min; Wang, Li; Song, Junyang; Wang, Xiping

2013-01-01

Background The phytohormone gibberellic acid (GA3) is widely used in the table grape industry to induce seedlessness in seeded varieties. However, there is a paucity of information concerning the mechanisms by which GAs induce seedlessness in grapes. Methodology/Principal Findings In an effort to systematically analyze the cause of this GA3-induced seed abortion, we conducted an in depth characterization of two seeded grape cultivars (‘Kyoho’ and ‘Red Globe’), along with a seedless cultivar (‘Thompson Seedless’), following treatment with GA3. In a similar fashion to the seedless control, which exhibited GA3-induced abortion of the seeds 9 days after full bloom (DAF), both ‘Kyoho’ and ‘Red Globe’ seeded varieties exhibited complete abortion of the seeds 15 DAF when treated with GA3. Morphological analyses indicated that while fertilization appeared to occur normally following GA3 treatment, as well as in the untreated seedless control cultivar, seed growth eventually ceased. In addition, we found that GA3 application had an effect on redox homeostasis, which could potentially cause cell damage and subsequent seed abortion. Furthermore, we carried out an analysis of antioxidant enzyme activities, as well as transcript levels from various genes believed to be involved in seed development, and found several differences between GA3-treated and untreated controls. Conclusion Therefore, it seems that the mechanisms driving GA3-induced seedlessness are similar in both seeded and seedless cultivars, and that the observed abortion of seeds may result at least in part from a GA3-induced increase in cell damage caused by reactive oxygen species, a decrease in antioxidant enzymatic activities, and an alteration of the expression of genes related to seed development. PMID:24224035

Phylogenetic diversification of Early Cretaceous seed plants: The compound seed cone of Doylea tetrahedrasperma.

PubMed

Rothwell, Gar W; Stockey, Ruth A

2016-05-01

Discovery of cupulate ovules of Doylea tetrahedrasperma within a compact, compound seed cone highlights the rich diversity of fructification morphologies, pollination biologies, postpollination enclosure of seeds, and systematic diversity of Early Cretaceous gymnosperms. Specimens were studied using the cellulose acetate peel technique, three-dimensional reconstructions (in AVIZO), and morphological phylogenetic analyses (in TNT). Doylea tetrahedrasperma has bract/fertile short shoot complexes helically arranged within a compact, compound seed cone. Complexes diverge from the axis as a single unit and separate distally into a free bract tip and two sporophylls. Each sporophyll bears a single, abaxial seed, recurved toward the cone axis, that is enveloped after pollinaton by sporophyll tissue, forming a closed cupule. Ovules are pollinated by bisaccate grains captured by micropylar pollination horns. The unique combination of characters shown by D. tetrahedrasperma includes the presence of cupulate seeds borne in conifer-like compound seed cones, an ovuliferous scale analogue structurally equivalent to the ovulate stalk of Ginkgo biloba, gymnospermous pollination, and nearly complete enclosure of mature seeds. These features characterize the Doyleales ord. nov., clearly distinguish it from the seed fern order Corystospermales, and allow for recognition of another recently described Early Cretaceous seed plant as a second species in genus Doylea. A morphological phylogenetic analysis highlights systematic relationships of the Doyleales ord. nov. and emphasizes the explosive phylogenetic diversification of gymnosperms that was underway at the time when flowering plants may have originated and/or first began to radiate. © 2016 Botanical Society of America.

Online gamma-camera imaging of 103Pd seeds (OGIPS) for permanent breast seed implantation

NASA Astrophysics Data System (ADS)

Ravi, Ananth; Caldwell, Curtis B.; Keller, Brian M.; Reznik, Alla; Pignol, Jean-Philippe

2007-09-01

Permanent brachytherapy seed implantation is being investigated as a mode of accelerated partial breast irradiation for early stage breast cancer patients. Currently, the seeds are poorly visualized during the procedure making it difficult to perform a real-time correction of the implantation if required. The objective was to determine if a customized gamma-camera can accurately localize the seeds during implantation. Monte Carlo simulations of a CZT based gamma-camera were used to assess whether images of suitable quality could be derived by detecting the 21 keV photons emitted from 74 MBq 103Pd brachytherapy seeds. A hexagonal parallel hole collimator with a hole length of 38 mm, hole diameter of 1.2 mm and 0.2 mm septa, was modeled. The design of the gamma-camera was evaluated on a realistic model of the breast and three layers of the seed distribution (55 seeds) based on a pre-implantation CT treatment plan. The Monte Carlo simulations showed that the gamma-camera was able to localize the seeds with a maximum error of 2.0 mm, using only two views and 20 s of imaging. A gamma-camera can potentially be used as an intra-procedural image guidance system for quality assurance for permanent breast seed implantation.

``From seed-to-seed'' experiment with wheat plants under space-flight conditions

NASA Astrophysics Data System (ADS)

Mashinsky, A.; Ivanova, I.; Derendyaeva, T.; Nechitailo, G.; Salisbury, F.

1994-11-01

An important goal with plant experiments in microgravity is to achieve a complete life cycle, the ``seed-to-seed experiment''. Some Soviet attempts to reach this goal are described, notably an experiment with the tiny mustard, Arabidopsis thaliana, in the Phyton 3 device on Salyut 7. Normal seeds were produced although yields were reduced and development was delayed. Several other experiments have shown abnormalities in plants grown in space. In recent work, plants of wheat (Triticum aestivum) were studied on the ground and then in a preliminary experiment in space. Biometric indices of vegetative space plants were 2 to 2.5 times lower than those of controls, levels of chlorophyll a and b were reduced (no change in the ratio of the two pigments), carotenoids were reduced, there was a serious imbalance in major minerals, and membrane lipids were reduced (no obvious change in lipid patterns). Following the preliminary studies, an attempt was made with the Svetoblock-M growth unit to grow a super-dwarf wheat cultivar through a life cycle. The experiment lasted 167 d on Mir. Growth halted from about day 40 to day 100, when new shoots appeared. Three heads had appeared in the boot (surrounded by leaves) when plants were returned to earth. One head was sterile, but 28 seeds matured on earth, and most of these have since produced normal plants and seeds. In principle, a seed-to-seed experiment with wheat should be successful in microgravity.

Increasing seed size and quality by manipulating BIG SEEDS 1 in legume species

USDA-ARS?s Scientific Manuscript database

Plant organs such as seeds are primary sources of food for both humans and animals. Seed size is one of the major agronomic traits that have been selected in crop plants during their domestication. Legume seeds are a major source of dietary proteins and oils. Here, we report a novel and conserved ro...

Ecological longevity of Polaskia chende (Cactaceae) seeds in the soil seed bank, seedling emergence and survival.

PubMed

Ordoñez-Salanueva, C A; Orozco-Segovia, A; Canales-Martínez, M; Seal, C E; Pritchard, H W; Flores-Ortiz, C M

2017-11-01

Soil seed banks are essential elements of plant population dynamics, enabling species to maintain genetic variability, withstand periods of adversity and persist over time, including for cactus species. However knowledge of the soil seed bank in cacti is scanty. In this study, over a 5-year period we studied the seed bank dynamics, seedling emergence and nurse plant facilitation of Polaskia chende, an endemic columnar cactus of central Mexico. P. chende seeds were collected for a wild population in Puebla, Mexico. Freshly collected seeds were sown at 25 °C and 12-h photoperiod under white light, far-red light and darkness. The collected seeds were divided in two lots, the first was stored in the laboratory and the second was use to bury seeds in open areas and beneath a shrub canopy. Seeds were exhumed periodically over 5 years. At the same time seeds were sown in open areas and beneath shrub canopies; seedling emergence and survival were recorded over different periods of time for 5 years. The species forms long-term persistent soil seed banks. The timing of seedling emergence via germination in the field was regulated by interaction between light, temperature and soil moisture. Seeds entered secondary dormancy at specific times according to the expression of environmental factors, demonstrating irregular dormancy cycling. Seedling survival of P. chende was improved under Acacia constricta nurse plants. Finally, plant facilitation affected the soil seed bank dynamics as it promoted the formation of a soil seed bank, but not its persistence. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Upgrading Yellow-Poplar Seeds

Treesearch

F. T. Bonner; G. L. Switzer

1971-01-01

Yellow-poplar seed lots can be upgraded considerably by dewinging in a debearder and then cleaning and separating the seeds into four specific-gravity fractions with a fractionating aspirator or a gravity separator. By this process, lots with an original soundness of 6 to 10 percent were upgraded to between 60 and 65 percent full seeds.

The Effect of Seed-borne Mycoflora from Sorghum and Foxtail Millet Seeds on Germination and Disease Transmission.

PubMed

Yago, Jonar I; Roh, Jae-Hwan; Bae, Soon-do; Yoon, Young-Nam; Kim, Hyun-Ju; Nam, Min-Hee

2011-09-01

The seed-borne mycoflora of sorghum and foxtail millet collected from different growing areas in South Korea were isolated and taxonomically identified using dry inspection, standard blotter and the agar plate method. We investigated the in vitro and in vivo germination rates of disinfected and non-disinfected seeds of sorghum and foxtail millet using sterilized and unsterilized soil. The percent recovery of seed-borne mycoflora from the seed components of sorghum and foxtail millet seeds was determined and an infection experiment using the dominant species was evaluated for seedling emergence and mortality. A higher number of seed-borne fungi was observed in sorghum compared to that of foxtail millet. Eighteen fungal genera with 34 fungal species were identified from the seeds of sorghum and 13 genera with 22 species were identified from the seeds of foxtail millet. Five dominant species such as Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme and Phoma sp. were recorded as seed-borne mycoflora in sorghum and 4 dominant species (Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme) were observed in foxtail millet. The in vitro and in vivo germination rates were higher using disinfected seeds and sterilized soil. More seed-borne fungi were recovered from the pericarp compared to the endosperm and seed embryo. The percent recovery of seed-borne fungi ranged from 2.22% to 60.0%, and Alternaria alternata, Curvularia lunata and 4 species of Fusarium were isolated from the endosperm and embryo of sorghum and foxtail millet. Inoculation of the dominant seed-borne fungi showed considerable mortality of seedlings. All the transmitted seed-borne fungi might well be a primary source of infection of sorghum and foxtail millet crops.

Effects of environmental variation during seed production on seed dormancy and germination.

PubMed

Penfield, Steven; MacGregor, Dana R

2017-02-01

The environment during seed production has major impacts on the behaviour of progeny seeds. It can be shown that for annual plants temperature perception over the whole life history of the mother can affect the germination rate of progeny, and instances have been documented where these affects cross whole generations. Here we discuss the current state of knowledge of signal transduction pathways controlling environmental responses during seed production, focusing both on events that take place in the mother plant and those that occur directly as a result of environmental responses in the developing zygote. We show that seed production environment effects are complex, involving overlapping gene networks active independently in fruit, seed coat, and zygotic tissues that can be deconstructed using careful physiology alongside molecular and genetic experiments. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The flight of Ruellia ciliatiflora seeds

NASA Astrophysics Data System (ADS)

Cooper, Eric; Mosher, Molly; Whitaker, Dwight

2017-11-01

Fruits of Ruellia ciliatiflora explosively launch seeds at velocities over 10 m/s, reaching distances of over 7 m. Through high speed video analysis of the seeds' flight, we have observed high rates of backspin of up to 1660 Hz, one of the fastest known rotational rates in the natural world. Analytical calculations that model the torques on the seeds as those of a Rayleigh Disk and incorporate the effects of gravity of the seeds' angles of attack, show that the seeds' backspin orientation is stable under gyroscopic procession. This stable backspin orientation maintains a small area in direction of motion, decreasing drag force on the seeds and thus increasing dispersal distance. From careful analysis of high-speed video of the seeds' flight we experimentally determine the seeds' drag coefficients and find that they are consistent with drag predicted for the streamlined orientation. By using backspin to ensure a streamlined orientation, the seeds are able to reduce the energy costs for seed dispersal by up to a factor of ten.

Comparison of germination and seed bank dynamics of dimorphic seeds of the cold desert halophyte Suaeda corniculata subsp. mongolica

PubMed Central

Cao, Dechang; Baskin, Carol C.; Baskin, Jerry M.; Yang, Fan; Huang, Zhenying

2012-01-01

Background and Aims Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but it is unknown how this difference contributes to maintenance and regeneration of populations. The primary aim of this study was to compare the seed bank dynamics, including dormancy cycling, of the two seed morphs (black and brown) of the cold desert halophyte Suaeda corniculata and, if differences were found, to determine their influence on regeneration of the species. Method Seeds of the two seed morphs were buried, exhumed and tested monthly for 24 months over a range of temperatures and salinities, and germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were also investigated for the two morphs. Key Results Black seeds had an annual dormancy/non-dormancy cycle, while brown seeds, which were non-dormant at maturity, remained non-dormant. Black seeds also exhibited an annual cycle in sensitivity of germination to salinity. Seedlings derived from black seeds emerged in July and August and those from brown seeds in May. Seedlings were recruited from 2·6 % of the black seeds and from 2·8 % of the brown seeds in the soil, and only 0·5 % and 0·4 % of the total number of black and brown seeds in the soil, respectively, gave rise to seedlings that survived to produce seeds. Salinity and water stress induced dormancy in black seeds and decreased viability of brown seeds. Brown seeds formed only a transient soil seed bank and black seeds a persistent seed bank. Conclusions The presence of a dormancy cycle in black but not in brown seeds of S. corniculata and differences in germination requirements of the two morphs cause them to differ in their germination dynamics. The study contributes to our limited knowledge of dormancy cycling and seed bank formation in species producing heteromorphic seeds. PMID:22975287

Comparison of germination and seed bank dynamics of dimorphic seeds of the cold desert halophyte Suaeda corniculata subsp. mongolica.

PubMed

Cao, Dechang; Baskin, Carol C; Baskin, Jerry M; Yang, Fan; Huang, Zhenying

2012-12-01

Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but it is unknown how this difference contributes to maintenance and regeneration of populations. The primary aim of this study was to compare the seed bank dynamics, including dormancy cycling, of the two seed morphs (black and brown) of the cold desert halophyte Suaeda corniculata and, if differences were found, to determine their influence on regeneration of the species. Seeds of the two seed morphs were buried, exhumed and tested monthly for 24 months over a range of temperatures and salinities, and germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were also investigated for the two morphs. Black seeds had an annual dormancy/non-dormancy cycle, while brown seeds, which were non-dormant at maturity, remained non-dormant. Black seeds also exhibited an annual cycle in sensitivity of germination to salinity. Seedlings derived from black seeds emerged in July and August and those from brown seeds in May. Seedlings were recruited from 2·6 % of the black seeds and from 2·8 % of the brown seeds in the soil, and only 0·5 % and 0·4 % of the total number of black and brown seeds in the soil, respectively, gave rise to seedlings that survived to produce seeds. Salinity and water stress induced dormancy in black seeds and decreased viability of brown seeds. Brown seeds formed only a transient soil seed bank and black seeds a persistent seed bank. The presence of a dormancy cycle in black but not in brown seeds of S. corniculata and differences in germination requirements of the two morphs cause them to differ in their germination dynamics. The study contributes to our limited knowledge of dormancy cycling and seed bank formation in species producing heteromorphic seeds.

Effects of germination time on seed morph ratio in a seed-dimorphic species and possible ecological significance

PubMed Central

Yang, Fan; Baskin, Jerry M.; Baskin, Carol C.; Yang, Xuejun; Cao, Dechang; Huang, Zhenying

2015-01-01

Background and Aims Diaspores of heteromorphic species may germinate at different times due to distinct dormancy-breaking and germination requirements, and this difference can influence life history traits. The primary aim of this study was to determine the effect of germination time of the two seed morphs of Suaeda corniculata subsp. mongolica on life history traits of the offspring. Methods Germinated brown and black seeds were sown on the 20th of each month from April to September in a simulated but near-natural habitat of the species. Phenological and vegetative traits of the maternal plants, and number, size and germination percentage of the offspring were determined. Key Results Germinated seeds sown late in the year produced smaller plants that had a higher proportion of non-dormant brown than dormant black seeds, and these brown seeds were larger than those produced by germinated seeds sown early in the year. The length of the seedling stage for brown seeds was shorter than that for black seeds, and the root/shoot ratio and reproductive allocation of plants from brown seeds were more variable than they were for plants from black seeds. Late-germinating brown seeds produced larger plants than late-germinating black seeds. Conclusions Altering the proportion of the two seed types in response to germination timing can help alleviate the adverse effects of delayed germination. The flexible strategy of a species, such as S. corniculata, that produces different proportions of dimorphic seeds in response to variation in germination timing may favour the maintenance and regeneration of the population in its unpredictable environment. PMID:25395107

Automated seed manipulation and planting

NASA Technical Reports Server (NTRS)

Garcia, Ray; Herrera, Javier; Holcomb, Scott; Kelly, Paul; Myers, Scott; Rosendo, Manny; Sivitz, Herbert; Wolsefer, Dave

1988-01-01

Activities for the Fall Semester, 1987 focused on investigating the mechanical/electrical properties of wheat seeds and forming various Seed Planting System (SPS) concepts based on those properties. The Electrical Division of the design group was formed to devise an SPS using electrostatic charge fields for seeding operations. Experiments concerning seed separation using electrical induction (rearranging of the charges within the seed) were conducted with promising results. The seeds, when exposed to the high voltage and low current field produced by a Van de Graff generator, were observed to move back and forth between two electrodes. An SPS concept has been developed based on this phenomena, and will be developed throughout the Spring Semester, 1988. The Mechanical Division centered on SPS concepts involving valves, pumps, and fluids to separate and deliver seeds. An SPS idea utilizing the pressure difference caused by air as it rushes out of holes drilled in the wall of a closed container has been formulated and will be considered for future development. Also, a system of seed separation and delivery employing a combination of centrifugal force, friction, and air flow was considered.

Tree Seed Technology Training Course - Instructor's Manual

Treesearch

F.T. Bonner; John A. Vozzo; W.W. Elam; S.B. Land

1994-01-01

This manual is intended primarily to train seed collectors, seed-plant managers, seed analysts, and nursery managers, but it can serve as a resource for any training course in forest regeneration. It includes both temperate and tropical tree species of all intended uses. The manual covers the following topics: seed biology, seed collection, seed handling, seed-quality...

Gastropod seed dispersal: an invasive slug destroys far more seeds in its gut than native gastropods.

PubMed

Blattmann, Tamara; Boch, Steffen; Türke, Manfred; Knop, Eva

2013-01-01

Seed dispersal is one of the most important mechanisms shaping biodiversity, and animals are one of the key dispersal vectors. Animal seed dispersal can directly or indirectly be altered by invasive organisms through the establishment of new or the disruption of existing seed dispersal interactions. So far it is known for a few gastropod species that they ingest and defecate viable plant seeds and consequently act as seed dispersers, referred to as gastropodochory. In a multi-species experiment, consisting of five different plant species and four different gastropod species, we tested with a fully crossed design whether gastropodochory is a general mechanism across native gastropod species, and whether it is altered by the invasive alien slug species Arion lusitanicus. Specifically, we hypothesized that a) native gastropod species consume the seeds from all tested plant species in equal numbers (have no preference), b) the voracious invasive alien slug A. lusitanicus--similarly to its herbivore behaviour--consumes a higher amount of seeds than native gastropods, and that c) seed viability is equal among different gastropod species after gut passage. As expected all tested gastropod species consumed all tested plant species. Against our expectation there was a difference in the amount of consumed seeds, with the largest and native mollusk Helix pomatia consuming most seeds, followed by the invasive slug and the other gastropods. Seed damage and germination rates did not differ after gut passage through different native species, but seed damage was significantly higher after gut passage through the invasive slug A. lusitanicus, and their germination rates were significantly reduced.

46 CFR 148.310 - Seed cake.

Code of Federal Regulations, 2011 CFR

2011-10-01

... apply to solvent-extracted rape seed meal, pellets, soya bean meal, cotton seed meal, or sunflower seed meal that— (1) Contains a maximum of 4 percent vegetable oil and a maximum of 15 percent vegetable oil... cake. (e) The seed cake must be kept as dry as practical at all times. (f) If the seed cake is solvent...

Scatter Hoarding of Seeds Confers Survival Advantages and Disadvantages to Large-Seeded Tropical Plants at Different Life Stages

PubMed Central

Kuprewicz, Erin K.

2015-01-01

Scatter hoarding of seeds by animals contributes significantly to forest-level processes, including plant recruitment and forest community composition. However, the potential positive and negative effects of caching on seed survival, germination success, and seedling survival have rarely been assessed through experimental studies. Here, I tested the hypothesis that seed burial mimicking caches made by scatter hoarding Central American agoutis (Dasyprocta punctate) enhances seed survival, germination, and growth by protecting seeds from seed predators and providing favorable microhabitats for germination. In a series of experiments, I used simulated agouti seed caches to assess how hoarding affects seed predation by ground-dwelling invertebrates and vertebrates for four plant species. I tracked germination and seedling growth of intact and beetle-infested seeds and, using exclosures, monitored the effects of mammals on seedling survival through time. All experiments were conducted over three years in a lowland wet forest in Costa Rica. The majority of hoarded palm seeds escaped predation by both invertebrates and vertebrates while exposed seeds suffered high levels of infestation and removal. Hoarding had no effect on infestation rates of D. panamensis, but burial negatively affected germination success by preventing endocarp dehiscence. Non-infested palm seeds had higher germination success and produced larger seedlings than infested seeds. Seedlings of A. alatum and I. deltoidea suffered high mortality by seed-eating mammals. Hoarding protected most seeds from predators and enhanced germination success (except for D. panamensis) and seedling growth, although mammals killed many seedlings of two plant species; all seedling deaths were due to seed removal from the plant base. Using experimental caches, this study shows that scatter hoarding is beneficial to most seeds and may positively affect plant propagation in tropical forests, although tradeoffs in seed

Examining Children's Models of Seed.

ERIC Educational Resources Information Center

Jewell, Natalie

2002-01-01

Reports research that examines children's models of seed. Explores the conceptions held by children (N=75) of germination and seed formation. Concludes that children hold a restricted meaning for the term 'seed'. (DDR)

Tree seed rain and seed removal, but not the seed bank, impede forest recovery in bracken (Pteridium aquilinum (L.) Kuhn)-dominated clearings in the African highlands.

PubMed

Ssali, Fredrick; Moe, Stein R; Sheil, Douglas

2018-04-01

Considerable areas dominated by bracken Pteridium aquilinum (L.) Kuhn occur worldwide and are associated with arrested forest recovery. How forest recovery is impeded in these areas remains poorly understood, especially in the African highlands. The component processes that can lead to recruitment limitation-including low seed arrival, availability and persistence-are important determinants of plant communities and offer a potential explanation for bracken persistence. We investigated key processes that can contribute to recruitment limitation in bracken-dominated clearings in the Bwindi Impenetrable National Park, Uganda. We examined if differences in seed rain (dispersal limitation), soil seed bank, or seed removal (seed viability and persistence) can, individually or in combination, explain the differences in tree regeneration found between bracken-dominated areas and the neighboring forest. These processes were assessed along ten 50-m transects crossing the forest-bracken boundary. When compared to the neighboring forest, bracken clearings had fewer seedlings (bracken 11,557 ± 5482 vs. forest 34,515 ± 6066 seedlings/ha), lower seed rain (949 ± 582 vs. 1605 ± 335 tree seeds m -2  year -1 ), comparable but sparse soil seed bank (304 ± 236 vs. 264 ± 99 viable tree seeds/m 2 ), higher seed removal (70.1% ± 2.4% vs. 40.6% ± 2.4% over a 3-day interval), and markedly higher rodent densities (25.7 ± 5.4 vs. 5.0 ± 1.6 rodents per 100 trapping sessions). Camera traps revealed that rodents were the dominant animals visiting the seeds in our seed removal study. Synthesis : Recruitment limitation contributes to both the slow recovery of forest in bracken-dominated areas, and to the composition of the tree species that occur. Low seed arrival and low persistence of unburied seeds can both explain the reduced density of seedlings found in bracken versus neighboring forest. Seed removal, likely due to rodents, in particular appears sufficient to

Colonization of citrus seed coats by 'Candidatus Liberibacter asiaticus': implications for seed transmission of the bacterium.

PubMed

Hilf, Mark E

2011-10-01

Huanglongbing is an economically damaging disease of citrus associated with infection by 'Candidatus Liberibacter asiaticus'. Transmission of the organism via infection of seeds has not been demonstrated but is a concern since some citrus varieties, particularly those used as rootstocks in commercial plantings are propagated from seed. We compared the incidence of detection of 'Ca. Liberibacter asiaticus' DNA in individual fruit peduncles, seed coats, seeds, and in germinated seedlings from 'Sanguenelli' sweet orange and 'Conners' grapefruit fruits sampled from infected trees. Using real-time quantitative PCR (qPCR) we detected pathogen DNA in nucleic acid extracts of 36 and 100% of peduncles from 'Sanguenelli' and from 'Conners' fruits, respectively. We also detected pathogen DNA in extracts of 37 and 98% of seed coats and in 1.6 and 4% of extracts from the corresponding seeds of 'Sanguenelli' and 'Conners', respectively. Small amounts of pathogen DNA were detected in 10% of 'Sanguenelli' seedlings grown in the greenhouse, but in none of 204 extracts from 'Conners' seedlings. Pathogen DNA was detected in 4.9% and in 89% of seed coats peeled from seeds of 'Sanguenelli' and 'Conners' which were germinated on agar, and in 5% of 'Sanguenelli' but in none of 164 'Conners' seedlings which grew from these seeds on agar. No pathogen DNA was detected in 'Ridge Pineapple' tissue at 3 months post-grafting onto 'Sanguenelli' seedlings, even when pathogen DNA had been detected initially in the 'Sanguenelli' seedling. Though the apparent colonization of 'Conners' seeds was more extensive and nearly uniform compared with 'Sanguenelli' seeds, no pathogen DNA was detected in 'Conners' seedlings grown from these seeds. For either variety, no association was established between the presence of pathogen DNA in fruit peduncles and seed coats and in seedlings.

Internal dispersal of seeds by waterfowl: effect of seed size on gut passage time and germination patterns

NASA Astrophysics Data System (ADS)

Figuerola, Jordi; Charalambidou, Iris; Santamaria, Luis; Green, Andy J.

2010-06-01

Long distance dispersal may have important consequences for gene flow and community structure. The dispersal of many plants depends on transport by vertebrate seed dispersers. The shapes of seed shadows produced by vertebrates depend both on movement patterns of the dispersers and on the dynamics and effects of passage through the disperser’s gut (i.e. the retention time, survival and germination of ingested seeds). A combination of experiments with captive waterbirds and aquatic plant seeds was used to analyse the following: (a) the effects of inter- and intra-specific variation in seed size and duck species on seed retention time in the gut and (b) the relationship between retention time and the percent germination and germination rates of seeds. Among the three Scirpus species used, those with smaller seeds showed higher survival after ingestion by birds and longer retention times inside their guts than those with larger seeds. For Potamogeton pectinatus, only seeds from the smaller size class (<8 mg) survived ingestion. Retention time affected the percent germination and germination rate of Scirpus seeds but in a manner that varied for the different plant and bird species studied. We recorded both linear and non-linear effects of retention time on percent germination. In addition, germination rate was positively correlated with retention time in Scirpus litoralis but negatively correlated in Scirpus lacustris. Small seed size can favour dispersal over larger distances. However, the effects of retention time on percent germination can modify the seed shadows produced by birds due to higher percent germination of seeds retained for short or intermediate periods. The changes in dispersal quality associated with dispersal distance (which is expected to be positively related to retention time) will affect the probability of seedling establishment over longer distances and, thus, the spatial characteristics of the effective seed shadow.

The Effect of Seed-borne Mycoflora from Sorghum and Foxtail Millet Seeds on Germination and Disease Transmission

PubMed Central

Yago, Jonar I.; Bae, Soon-do; Yoon, Young-Nam; Kim, Hyun-Ju; Nam, Min-hee

2011-01-01

The seed-borne mycoflora of sorghum and foxtail millet collected from different growing areas in South Korea were isolated and taxonomically identified using dry inspection, standard blotter and the agar plate method. We investigated the in vitro and in vivo germination rates of disinfected and non-disinfected seeds of sorghum and foxtail millet using sterilized and unsterilized soil. The percent recovery of seed-borne mycoflora from the seed components of sorghum and foxtail millet seeds was determined and an infection experiment using the dominant species was evaluated for seedling emergence and mortality. A higher number of seed-borne fungi was observed in sorghum compared to that of foxtail millet. Eighteen fungal genera with 34 fungal species were identified from the seeds of sorghum and 13 genera with 22 species were identified from the seeds of foxtail millet. Five dominant species such as Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme and Phoma sp. were recorded as seed-borne mycoflora in sorghum and 4 dominant species (Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme) were observed in foxtail millet. The in vitro and in vivo germination rates were higher using disinfected seeds and sterilized soil. More seed-borne fungi were recovered from the pericarp compared to the endosperm and seed embryo. The percent recovery of seed-borne fungi ranged from 2.22% to 60.0%, and Alternaria alternata, Curvularia lunata and 4 species of Fusarium were isolated from the endosperm and embryo of sorghum and foxtail millet. Inoculation of the dominant seed-borne fungi showed considerable mortality of seedlings. All the transmitted seed-borne fungi might well be a primary source of infection of sorghum and foxtail millet crops. PMID:22783105

Towards better metrics and policymaking for seed system development: Insights from Asia's seed industry.

PubMed

Spielman, David J; Kennedy, Adam

2016-09-01

Since the 1980s, many developing countries have introduced policies to promote seed industry growth and improve the delivery of modern science to farmers, often with a long-term goal of increasing agricultural productivity in smallholder farming systems. Public, private, and civil society actors involved in shaping policy designs have, in turn, developed competing narratives around how best to build an innovative and sustainable seed system, each with varying goals, values, and levels of influence. Efforts to strike a balance between these narratives have often played out in passionate discourses surrounding seed rules and regulations. As a result, however, policymakers in many countries have expressed impatience with the slow progress on enhancing the contribution of a modern seed industry to the overarching goal of increasing agricultural productivity growth. One reason for this slow progress may be that policymakers are insufficiently cognizant of the trade-offs associated with rules and regulations required to effectively govern a modern seed industry. This suggests the need for new data and analysis to improve the understanding of how seed systems function. This paper explores these issues in the context of Asia's rapidly growing seed industry, with illustrations from seed markets for maize and several other crops, to highlight current gaps in the metrics used to analyze performance, competition, and innovation. The paper provides a finite set of indicators to inform policymaking on seed system design and monitoring, and explores how these indicators can be used to inform current policy debates in the region.

Changes in seed water status as characterized by NMR in developing soybean seed grown under moisture stress conditions

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

Krishnan, P., E-mail: pkrishnan@iari.res.in; Singh, Ravender; Verma, A.P.S.

Highlights: • In developing soybean seeds, moisture stress resulted in more proportion of water to bound state. • These changes are further corroborated by concomitant changes in seed metabolites. • Thus there exists a moisture stress and development stage dependence of seed tissue water status. - Abstract: Changes in water status of developing seeds of Soybean (Glycine max L. Merrill.) grown under different moisture stress conditions were characterized by proton nuclear magnetic resonance (NMR)- spin–spin relaxation time (T{sub 2}). A comparison of the seed development characteristics, composition and physical properties indicated that, characteristics like seed weight, seed number/ear, rate ofmore » seed filling increased with development stages but decreased with moisture stress conditions. The NMR- spin–spin relaxation (T{sub 2}) component like bound water increased with seed maturation (40–50%) but decreased with moisture stress conditions (30–40%). The changes in seed water status to increasing levels of moisture stress and seed maturity indicates that moisture stress resulted in more proportion of water to bound state and intermediate state and less proportion of water in free-state. These changes are further corroborated by significant changes in protein and starch contents in seeds under high moisture stress treatments. Thus seed water status during its development is not only affected by development processes but also by moisture stress conditions. This study strongly indicated a clear moisture stress and development stage dependence of seed tissue water status in developing soybean seeds.« less

Levitation and guidance force relaxations of the single-seeded and multi-seeded YBCO superconductors

NASA Astrophysics Data System (ADS)

Abdioglu, M.; Ozturk, K.; Kabaer, M.; Ekici, M.

2018-01-01

The stable levitation and guidance forces at higher force levels are important parameters for technological applicability of high temperature superconductors (HTSs) in Maglev and Flywheel energy storage systems. In this study, we have investigated the levitation and guidance force relaxation of both the single-seeded and multi-seeded YBCOs for different (HTS)-permanent magnetic guideway (PMG) arrangements in different cooling heights (CH). The measured saturated force values of Halbach PMG arrangements are bigger than the maximum force values of other PMGs. It is determined that the normalized magnetic levitation force (MLF) and normalized guidance force (GF) relaxation rate values decrease while the relaxation rates increase with increasing magnetic pole number and the effective external magnetic field area for both the single-seeded and multi-seeded YBCO. Also it can be said that the force stability at the higher force value of Halbach PMG arrangement indicates that the relaxation quality of Halbach PMG is better than that of the others. Additionally, it can be said that both the MLF and GF relaxation qualities of the multi-seeded YBCOs are better than that of the single-seeded ones. This magnetic force and relaxation results of the single-seeded and multi-seeded YBCOs are useful to optimize the loading capacity and lateral reliability of HTS Maglev and similar magnetic bearing systems.

Effects of seed predators of different body size on seed mortality in Bornean logged forest.

PubMed

Hautier, Yann; Saner, Philippe; Philipson, Christopher; Bagchi, Robert; Ong, Robert C; Hector, Andy

2010-07-19

The Janzen-Connell hypothesis proposes that seed and seedling enemies play a major role in maintaining high levels of tree diversity in tropical forests. However, human disturbance may alter guilds of seed predators including their body size distribution. These changes have the potential to affect seedling survival in logged forest and may alter forest composition and diversity. We manipulated seed density in plots beneath con- and heterospecific adult trees within a logged forest and excluded vertebrate predators of different body sizes using cages. We show that small and large-bodied predators differed in their effect on con- and heterospecific seedling mortality. In combination small and large-bodied predators dramatically decreased both con- and heterospecific seedling survival. In contrast, when larger-bodied predators were excluded small-bodied predators reduced conspecific seed survival leaving seeds coming from the distant tree of a different species. Our results suggest that seed survival is affected differently by vertebrate predators according to their body size. Therefore, changes in the body size structure of the seed predator community in logged forests may change patterns of seed mortality and potentially affect recruitment and community composition.

[Seed vigor evaluation based on adversity resistance index of wheat seed germination under stress conditions.

PubMed

Chen, Lei Tai; Sun, Ai Qing; Yang, Min; Chen, Lu Lu; Ma, Xue Li; Li, Mei Ling; Yin, Yan Ping

2016-09-01

A total of 16 wheat cultivars were selected to detect seed vigor of different genotypes using standard germination test, seed germination test under stress conditions and field emergence test. The adversity resistance indices of seed vigor indices and field emergence percentage under different germination conditions were used as the indices to evaluate adversity resistance. Principal component analysis and cluster analysis were used for the comprehensive evaluation of seed vigor. Results showed that drought stress, artificial aging and cold soaking treatments affected seed vigor to some extent. The adversity resistance indices of the artificial aging and cold soaking tests were significantly positively correlated with the field emergence percentage, while the adversity resistance index of drought stress test had no significant correlation with the field emergence percentage. 16 wheat cultivars were classified as three groups based on the principal component analysis and cluster analysis. Yunong 949, Yumai 49-198, Luyuan 502, Zhengyumai 9987, Shimai 21, Shannong 23, and Shixin 828 belonged to high vigor seeds. Xunong 5, Yunong 982, Tangmai 8, Jimai 20, Jimai 22, Jinan 17, and Shannong 20 belonged to medium vigor seeds. The other two cultivars, Chang 4738 and Lunxuan 061, belonged to low vigor seeds.

Effects of Seed Predators of Different Body Size on Seed Mortality in Bornean Logged Forest

PubMed Central

Hautier, Yann; Saner, Philippe; Philipson, Christopher; Bagchi, Robert; Ong, Robert C.; Hector, Andy

2010-01-01

Background The Janzen-Connell hypothesis proposes that seed and seedling enemies play a major role in maintaining high levels of tree diversity in tropical forests. However, human disturbance may alter guilds of seed predators including their body size distribution. These changes have the potential to affect seedling survival in logged forest and may alter forest composition and diversity. Methodology/Principal Findings We manipulated seed density in plots beneath con- and heterospecific adult trees within a logged forest and excluded vertebrate predators of different body sizes using cages. We show that small and large-bodied predators differed in their effect on con- and heterospecific seedling mortality. In combination small and large-bodied predators dramatically decreased both con- and heterospecific seedling survival. In contrast, when larger-bodied predators were excluded small-bodied predators reduced conspecific seed survival leaving seeds coming from the distant tree of a different species. Conclusions/Significance Our results suggest that seed survival is affected differently by vertebrate predators according to their body size. Therefore, changes in the body size structure of the seed predator community in logged forests may change patterns of seed mortality and potentially affect recruitment and community composition. PMID:20657841

[Study on seed testing for Salvia miltiorrhiza].

PubMed

Dan, Hong-mei; Qi, Jian-jun; Zhou, Li-li; Li, Xian-en

2008-09-01

To establish a seed testing methods for Salvia miltiorrhiza. Referring to the International Seed Testing Rules made by ISTA and the Seed Testing for Crops (GB/T3543. 1-1995) issued by China. The seeds are selected by winnowing; the seed purity is about 50%-60%; 100 grain weight is used to determine the quality of the seed; the seed moisture content is determined by air drying, the drying hour is 3 h. Seed viability is tested by TFC method.

Quantification and characterization of chemically-and thermally-labile and recalcitrant biochar fractions.

PubMed

Bakshi, Santanu; Banik, Chumki; Laird, David A

2018-03-01

The C:N ratios of biochar labile fractions is important for assessing biochar stability and N cycling in soil. Here we compare chemically and thermally labile fractions for nine biochars produced from five biomass feedstocks using four production techniques. Biochar fractionation methods included proximate analysis, hot water extraction, acid and base extractions (0.05 M, 0.5 M, 1 M, 2 M, 3 M, and 6 M of either H 2 SO 4 or NaOH), and oxidation with 15% H 2 O 2 and 0.33 M KMnO 4 (pH 7.2). Results show chemical addition reactions cause underestimation of mass of the labile fraction for chemical extraction and oxidation procedures but not the thermal procedure. Estimates of C and N in labile and recalcitrant fractions were not adversely affected by addition reactions, because solvents were independent of C or N. Results indicate that herbaceous biochars may be a source of N fertility while hardwood biochars may immobilize N during the first few years after biochar application to soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Outcome of Boyd-McLeod procedure for recalcitrant lateral epicondylitis of elbow.

PubMed

Reddy, V R M; Satheesan, K S; Bayliss, N

2011-08-01

Various surgical procedures including percutaneous and open release and arthroscopic procedures have been described to treat recalcitrant tennis elbow. We present the outcome of Boyd-McLeod surgical procedure for tennis elbow resistant to non-operative treatment in twenty-seven patients (twenty-nine limbs). Boyd McLeod procedure involves excision of the proximal portion of the annular ligament, release of the origin of the extensor muscles, excision of the bursa if present, and excision of the synovial fringe. The average time interval from the onset of symptoms of tennis elbow until surgery was 28 months (range 8-72 months). Of those patients, 91% reported complete relief of symptoms with return to full normal activities including sports. Average post-operative time for return to professional/recreational activity was 5 weeks. One case developed pain secondary to ectopic bone formation after surgery, which settled after excision, and in another there was no pain relief with Boyd McLeod procedure. Two patients had scar tenderness that did not affect the final outcome. We conclude that Boyd-McLeod procedure is an effective treatment option in patients with resistant lateral epicondylitis.

A study on seed characteristics and seed bank of Spartina alterniflora at saltmarshes in the Yangtze Estuary, China

NASA Astrophysics Data System (ADS)

Xiao, Derong; Zhang, Liquan; Zhu, Zhenchang

2009-06-01

Since Spartina alterniflora was introduced into the Chongming Dongtan Nature Reserve in 1995, there has been a rapid expansion of this species, seriously threatening the overall biodiversity. In this study, the seed production, germination characteristics and soil seed bank of S. aterniflora were studied at the nature reserve along an intertidal gradient where this invasive species distributed and spread. The results showed that the middle intertidal zone (MIT) had the largest seed production and higher viability than those of lower (LIT) and higher (HIT) intertidal zones. The differences in seed production among these sites were largely dependent on the higher percentage of fruiting culms, longer spike and higher seed number per spike. The differences in seed viability among these sampling sites seemed largely dependent on the higher seed weight at the site MIT. The chilling treatment (at low temperature and in moist conditions) could significantly enhance the germinability of S. alterniflora seeds and shorten the time of onset seed germination. The seeds from the site MIT had much higher germinability than the sites LIT and HIT. The highest density of soil seed bank was recorded at the site of MIT, where had the highest seed production. By July, before there was any replenishment with fresh seeds from the current year, the soil seed bank was completely exhausted and the persistent time of soil seed bank for S. alterniflora was less than 9 months, which is in agreement with that of the transient seed bank. The results from this study indicated that the seed propagation could have an important attribution to the spreading of this invasive plant and the implications in terms of controlling and managing the invasion of S. alterniflora at the nature reserve were discussed.

Retarded germination of Nicotiana tabacum seeds following insertion of exogenous DNA mimics the seed persistent behavior

PubMed Central

Gagliardi, Assunta; Zaninelli, Mauro; Bini, Luca; Baldi, Antonella; Caccianiga, Marco; Reggi, Serena; Rossi, Luciana

2017-01-01

Tobacco seeds show a coat-imposed dormancy in which the seed envelope tissues (testa and endosperm) impose a physical constraint on the radicle protrusion. The germination-limiting process is represented by the endosperm rupture which is induced by cell-wall weakening. Transgenic tobacco seeds, obtained by insertion of exogenous genes codifying for seed-based oral vaccines (F18 and VT2eB), showed retarded germination with respect to the wild type and modified the expression of endogenous proteins. Morphological and proteomic analyses of wild type and transgenic seeds revealed new insights into factors influencing seed germination. Our data showed that the interference of exogenous DNA influences the germination rather than the dormancy release, by modifying the maturation process. Dry seeds of F18 and VT2eB transgenic lines accumulated a higher amount of reserve and stress–related proteins with respect to the wild type. Moreover, the storage proteins accumulated in tobacco F18 and VT2eB dry seeds have structural properties that do not enable the early limited proteolysis observed in the wild type. Morphological observations by electron and light microscopy revealed a retarded mobilization of the storage material from protein and lipid bodies in transgenic seeds, thus impairing water imbibition and embryo elongation. In addition, both F18 and VT2eB dry seeds are more rounded than the wild type. Both the morphological and biochemical characteristics of transgenic seeds mimic the seed persistent profile, in which their roundness enables them to be buried in the soil, while the higher content of storage material enables the hypocotyl to elongate more and the cotyledons to emerge. PMID:29216220

Retarded germination of Nicotiana tabacum seeds following insertion of exogenous DNA mimics the seed persistent behavior.

PubMed

Onelli, Elisabetta; Moscatelli, Alessandra; Gagliardi, Assunta; Zaninelli, Mauro; Bini, Luca; Baldi, Antonella; Caccianiga, Marco; Reggi, Serena; Rossi, Luciana

2017-01-01

Tobacco seeds show a coat-imposed dormancy in which the seed envelope tissues (testa and endosperm) impose a physical constraint on the radicle protrusion. The germination-limiting process is represented by the endosperm rupture which is induced by cell-wall weakening. Transgenic tobacco seeds, obtained by insertion of exogenous genes codifying for seed-based oral vaccines (F18 and VT2eB), showed retarded germination with respect to the wild type and modified the expression of endogenous proteins. Morphological and proteomic analyses of wild type and transgenic seeds revealed new insights into factors influencing seed germination. Our data showed that the interference of exogenous DNA influences the germination rather than the dormancy release, by modifying the maturation process. Dry seeds of F18 and VT2eB transgenic lines accumulated a higher amount of reserve and stress-related proteins with respect to the wild type. Moreover, the storage proteins accumulated in tobacco F18 and VT2eB dry seeds have structural properties that do not enable the early limited proteolysis observed in the wild type. Morphological observations by electron and light microscopy revealed a retarded mobilization of the storage material from protein and lipid bodies in transgenic seeds, thus impairing water imbibition and embryo elongation. In addition, both F18 and VT2eB dry seeds are more rounded than the wild type. Both the morphological and biochemical characteristics of transgenic seeds mimic the seed persistent profile, in which their roundness enables them to be buried in the soil, while the higher content of storage material enables the hypocotyl to elongate more and the cotyledons to emerge.

Comparisons of seed longevity under simulated aging and genebank storage conditions using brassicaceae seeds

USDA-ARS?s Scientific Manuscript database

Seeds survive for years under dry conditions but then viability crashes without warning. Efforts to provide high quality seeds to customers, breed longer-living seeds, or to investigate the underlying causes of deterioration during storage prompt the need for a reliable measure of the longevity phe...

SU-F-T-39: Comparing Nomograms for Ordering of Palladium-103 Seeds for Dynamic Intraoperative Prostate Seed Implantation

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

Taylor, P; Wang, L; Riegel, A

Purpose: Several nomograms exist for the purpose of ordering palladium- 103 seeds for permanent prostate seed implants. Excess seeds pose additional radiation safety risks and increase the cost of care. This study compared three seed ordering nomograms with seed counts from dynamic intra-operative PSI to determine (1) the cause of excess seeds and (2) the optimal nomogram for our institution. Methods: Pre-operative and intra-operative clinical data were collected for 100 Gy (n=151) and 125 Gy (n=224) prostate seed implants. The number of implanted seeds which would have given D90=100% was normalized to that criteria and seed strength of 2U. Thismore » was plotted against intra-operative prostate volume and compared to two previously published nomograms and an in-house nomogram. A linear fit was produced and confidence intervals were calculated. The causes of excess seeds were assessed by comparing pre- and intra-operative prostate volumes, variability of D90 around 100%, and variance of seed strength from 2U. Results: Of the 375 total cases, 97.6% had excess seeds. On average, 27.17±12.91% of ordered seeds were wasted. Of this percentage, 6.98±5.47% of excess seeds were due to overestimation of pre-operative prostate volume, 1.10±0.88% were due to D90<100%, 1.17±0.67% were due to seed strength over 2U, and 17.36±7.79% could not be directly attributed to a specific reason. The latter percentage may be due to overestimation of the in-house nomogram. Two of three nomograms substantially overestimated the number of seeds required. The third nomogram underestimated the required seed number for smaller prostate treatment volume. A linear fit to the clinical data was derived and 99.9% confidence intervals were calculated. Conclusion: Over 85% of clinical cases wasted over 15% of ordered seeds. Two of three nomograms overestimated the required number of seeds. The upper 99.9% C.I. of the clinical data may provide a more reasonable nomogram for Pd-103 seed ordering.« less

Degradation and intermediates of diclofenac as instructive example for decomposition of recalcitrant pharmaceuticals by hydroxyl radicals generated with pulsed corona plasma in water.

PubMed

Banaschik, Robert; Jablonowski, Helena; Bednarski, Patrick J; Kolb, Juergen F

2018-01-15

Seven recalcitrant pharmaceutical residues (diclofenac, 17α-ethinylestradiol, carbamazepine, ibuprofen, trimethoprim, diazepam, diatrizoate) were decomposed by pulsed corona plasma generated directly in water. The detailed degradation pathway was investigated for diclofenac and 21 intermediates could be identified in the degradation cascade. Hydroxyl radicals have been found primarily responsible for decomposition steps. By spin trap enhanced electron paramagnetic resonance spectroscopy (EPR), OH-adducts and superoxide anion radical adducts were detected and could be distinguished applying BMPO as a spin trap. The increase of concentrations of adducts follows qualitatively the increase of hydrogen peroxide concentrations. Hydrogen peroxide is eventually consumed in Fenton-like processes but the concentration is continuously increasing to about 2mM for a plasma treatment of 70min. Degradation of diclofenac is inversely following hydrogen peroxide concentrations. No qualitative differences between byproducts formed during plasma treatment or due to degradation via Fenton-induced processes were observed. Findings on degradation kinetics of diclofenac provide an instructive understanding of decomposition rates for recalcitrant pharmaceuticals with respect to their chemical structure. Accordingly, conclusions can be drawn for further development and a first risk assessment of the method which can also be applied towards other AOPs that rely on the generation of hydroxyl radicals. Copyright © 2017 Elsevier B.V. All rights reserved.

Postfire drill-seeding of Great Basin plants: Effects of contrasting drills on seeded and nonseeded species

Treesearch

Jeffrey E. Ott; Robert D. Cox; Nancy L. Shaw; Beth A. Newingham; Amy C. Ganguli; Mike Pellant; Bruce A. Roundy; Dennis L. Eggett

2016-01-01

Objectives of postfire seeding in the Great Basin include reestablishment of perennial cover, suppression of exotic annual weeds, and restoration of diverse plant communities. Nonconventional seeding techniques may be required when seeding mixes of grasses, forbs, and shrubs containing seeds of different sizes. We conducted an operational-scale experiment to...

Seed germination, seedling traits, and seed bank of the tree Moringa peregrina (Moringaceae) in a hyper-arid environment.

PubMed

Gomaa, Nasr H; Picó, F Xavier

2011-06-01

Water-limited hot environments are good examples of hyper-aridity. Trees are scarce in these environments but some manage to survive, such as the tree Moringa peregrina. Understanding how trees maintain viable populations in extremely arid environments may provide insight into the adaptive mechanisms by which trees cope with extremely arid weather conditions. This understanding is relevant to the current increasing aridity in several regions of the world. Seed germination experiments were conducted to assess variation in seed mass, seed germination, and seedling traits of Moringa peregrina plants and the correlations among these traits. A seed burial experiment was also designed to study the fate of M. peregrina seeds buried at two depths in the soil for two time periods. On average, seeds germinated in three days and seedling shoots grew 0.7 cm per day over three weeks. Larger seeds decreased germination time and increased seedling growth rates relative to smaller seeds. Seeds remained quiescent in the soil and germination was very high at both depths and burial times. The after-ripening time of Moringa peregrina seeds is short and seeds germinate quickly after imbibition. Plants of M. peregrina may increase in hyper-arid environments from seeds with larger mass, shorter germination times, and faster seedling growth rates. The results also illustrate the adjustment in allocation to seed biomass and correlations among seed and seedling traits that allows M. peregrina to be successful in coping with aridity in its environment.

Gibberellin induces alpha-amylase gene in seed coat of Ipomoea nil immature seeds.

PubMed

Nakajima, Masatoshi; Nakayama, Akira; Xu, Zheng-Jun; Yamaguchi, Isomaro

2004-03-01

Two full-length cDNAs encoding gibberellin 3-oxidases, InGA3ox1 and InGA3ox2, were cloned from developing seeds of morning glory (Ipomoea nil (Pharbitis nil) Choisy cv. Violet) with degenerate-PCR and RACEs. The RNA-blot analysis for these clones revealed that the InGA3ox2 gene was organ-specifically expressed in the developing seeds at 6-18 days after anthesis. In situ hybridization showed the signals of InGA3ox2 mRNA in the seed coat, suggesting that active gibberellins (GAs) were synthesized in the tissue, although no active GA was detected there by immunohistochemistry. In situ hybridization analysis for InAmy1 (former PnAmy1) mRNA showed that InAmy1 was also synthesized in the seed coat. Both InGA3ox2 and InAmy1 genes were expressed spatially overlapped without a clear time lag, suggesting that both active GAs and InAmy1 were synthesized almost simultaneously in seed coat and secreted to the integument. These observations support the idea that GAs play an important role in seed development by inducing alpha-amylase.

Seed size variation in the palm Euterpe edulis and the effects of seed predators on germination and seedling survival

NASA Astrophysics Data System (ADS)

Pizo, Marco A.; Von Allmen, Christiane; Morellato, L. Patricia C.

2006-05-01

Intraspecific variation in seed size is common in wild plant populations and has important consequences for the reproductive success of individual plants. Multiple, often conflicting evolutionary forces mediated by biotic as well as abiotic agents may maintain such a variation. In this paper we assessed seed size variation in a population of the threatened, commercially important palm Euterpe edulis in southeast Brazil. We investigated (i) how this variation affects the probability of attack by vertebrate and invertebrate post-dispersal seed predators, and (ii) if seed size influences the outcome of seeds damaged by beetles in terms of seed germination and early survival of seedlings. Euterpe edulis seeds varied in diameter from 8.3 to 14.1 mm. Neither insects nor rodents selected the seeds they preyed upon based on seed size. Seed germination and total, shoot and root biomasses of one-year seedlings were significantly and positively affected by seed size. Root biomass and seedling survival were negatively affected by seed damage caused by a scolytid beetle ( Coccotrypes palmarum) whose adults bore into seeds to consume part of the endosperm, but do not oviposit on them. Seed size had a marginally significant effect on seedling survival. Therefore, if any advantage is accrued by E. edulis individuals producing large seeds, this is because of greater seed germination success and seedling vigor. If this is so, even a relatively narrow range of variation in seed size as observed in the E. edulis population studied may translate into differential success of individual plants.

Genetic Analysis of Seed-Soluble Oligosaccharides in Relation to Seed Storability of Arabidopsis1

PubMed Central

Bentsink, Leónie; Alonso-Blanco, Carlos; Vreugdenhil, Dick; Tesnier, Karine; Groot, Steven P.C.; Koornneef, Maarten

2000-01-01

Seed oligosaccharides (OSs) and especially raffinose series OSs (RSOs) are hypothesized to play an important role in the acquisition of desiccation tolerance and consequently in seed storability. In the present work we analyzed the seed-soluble OS (sucrose, raffinose, and stachyose) content of several Arabidopsis accessions and thus identified the genotype Cape Verde Islands having a very low RSO content. By performing quantitative trait loci (QTL) mapping in a recombinant inbred line population, we found one major QTL responsible for the practically monogenic segregation of seed stachyose content. This locus also affected the content of the two other OSs, sucrose, and raffinose. Two candidate genes encoding respectively for galactinol synthase and raffinose synthase were located within the genomic region around this major QTL. In addition, three smaller-effect QTL were identified, each one specifically affecting the content of an individual OS. Seed storability was analyzed in the same recombinant inbred line population by measuring viability (germination) under two different seed aging assays: after natural aging during 4 years of dry storage at room temperature and after artificial aging induced by a controlled deterioration test. Thus, four QTL responsible for the variation of this trait were mapped. Comparison of the QTL genetic positions showed that the genomic region containing the major OS locus did not significantly affect the seed storability. We concluded that in the studied material neither RSOs nor sucrose content had a specific effect on seed storability. PMID:11115877

Seed-Specific Overexpression of the Pyruvate Transporter BASS2 Increases Oil Content in Arabidopsis Seeds

PubMed Central

Lee, Eun-Jung; Oh, Minwoo; Hwang, Jae-Ung; Li-Beisson, Yonghua; Nishida, Ikuo; Lee, Youngsook

2017-01-01

Seed oil is important not only for human and animal nutrition, but also for various industrial applications. Numerous genetic engineering strategies have been attempted to increase the oil content per seed, but few of these strategies have involved manipulating the transporters. Pyruvate is a major source of carbon for de novo fatty acid biosynthesis in plastids, and the embryo's demand for pyruvate is reported to increase during active oil accumulation. In this study, we tested our hypothesis that oil biosynthesis could be boosted by increasing pyruvate flux into plastids. We expressed the known plastid-localized pyruvate transporter BILE ACID:SODIUM SYMPORTER FAMILY PROTEIN 2 (BASS2) under the control of a seed-specific soybean (Glycine max) glycinin-1 promoter in Arabidopsis thaliana. The resultant transgenic Arabidopsis plants (OEs), which expressed high levels of BASS2, produced seeds that were larger and heavier and contained 10–37% more oil than those of the wild type (WT), but were comparable to the WT seeds in terms of protein and carbohydrate contents. The total seed number did not differ significantly between the WT and OEs. Therefore, oil yield per plant was increased by 24–43% in the OE lines compared to WT. Taken together, our results demonstrate that seed-specific overexpression of the pyruvate transporter BASS2 promotes oil production in Arabidopsis seeds. Thus, manipulating the level of specific transporters is a feasible approach for increasing the seed oil content. PMID:28265278

Seeding big sagebrush successfully on Intermountain rangelands

Treesearch

Susan E. Meyer; Thomas W. Warren

2015-01-01

Big sagebrush can be seeded successfully on climatically suitable sites in the Great Basin using the proper seeding guidelines. These guidelines include using sufficient quantities of high-quality seed of the correct subspecies and ecotype, seeding in late fall to mid-winter, making sure that the seed is not planted too deeply, and seeding into an environment...

Global biogeography of seed dormancy is determined by seasonality and seed size: a case study in the legumes.

PubMed

Rubio de Casas, Rafael; Willis, Charles G; Pearse, William D; Baskin, Carol C; Baskin, Jerry M; Cavender-Bares, Jeannine

2017-06-01

Seed dormancy is expected to provide ecological advantages by adjusting germination to the favorable growth period. However, many species produce nondormant seeds, particularly in wet tropical forests, a biogeographic pattern that is not well accounted for in current models. We hypothesized that the global distribution of dormant seeds derives from their adaptive value in predictably fluctuating (i.e. seasonal) environments. However, the advantage conferred by dormancy might ultimately depend on other seed attributes, particularly size. This general model was tested within a phylogenetically informed framework using a data set comprising > 216 000 world-wide observations of Fabaceae, spanning three orders of magnitude in seed size and including both dormant and nondormant seeds. Our results confirmed our hypothesis: nondormant seeds can only evolve in climates with long growing seasons and/or in lineages that produce larger seeds. Conversely, dormancy should be evolutionarily stable in temperate lineages with small seeds. When the favorable season is fleeting, seed dormancy is the only adaptive strategy. Based on these results, we predict that, within a given lineage, taxa producing larger, nondormant seeds will necessarily predominate in aseasonal environments, while plants bearing small, dormant seeds will be dominant under short growing seasons. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Disturbance frequency and vertical distribution of seeds affect long-term population dynamics: a mechanistic seed bank model.

PubMed

Eager, Eric Alan; Haridas, Chirakkal V; Pilson, Diana; Rebarber, Richard; Tenhumberg, Brigitte

2013-08-01

Seed banks are critically important for disturbance specialist plants because seeds of these species germinate only in disturbed soil. Disturbance and seed depth affect the survival and germination probability of seeds in the seed bank, which in turn affect population dynamics. We develop a density-dependent stochastic integral projection model to evaluate the effect of stochastic soil disturbances on plant population dynamics with an emphasis on mimicking how disturbances vertically redistribute seeds within the seed bank. We perform a simulation analysis of the effect of the frequency and mean depth of disturbances on the population's quasi-extinction probability, as well as the long-term mean and variance of the total density of seeds in the seed bank. We show that increasing the frequency of disturbances increases the long-term viability of the population, but the relationship between the mean depth of disturbance and the long-term viability of the population are not necessarily monotonic for all parameter combinations. Specifically, an increase in the probability of disturbance increases the long-term viability of the total seed bank population. However, if the probability of disturbance is too low, a shallower mean depth of disturbance can increase long-term viability, a relationship that switches as the probability of disturbance increases. However, a shallow disturbance depth is beneficial only in scenarios with low survival in the seed bank.

Phomopsis seed decay of soybean

USDA-ARS?s Scientific Manuscript database

Soybean Phomopsis seed decay (PSD) causes poor seed quality and suppresses yield in most soybean-growing countries. The disease is caused primarily by the fungal pathogen Phomopsis longicolla along with other Phomopsis and Diaporthe spp. Infected seed range from symptomless to shriveled, elongated, ...

Effect of fire on a seed bank pathogen and on seeds of its host Bromus tectorum

Treesearch

J. Beckstead; S.E. Meyer; L.E. Street; P.S. Allen

2010-01-01

The generalist pathogen Pyrenophora semeniperda (Brittlebank and Adam) Shoemaker occurs primarily in cheatgrass (Bromus tectorum L.) seed banks, where it causes high seed mortality (Beckstead et al. 2007; Meyer et al. 2007). How does fire impact survival of a fungal seed pathogen, P. semeniperda, versus survival of the seeds of its cheatgrass host, the invasive Bromus...

Incidence of seed-borne fungi and aflatoxins in Sudanese lentil seeds.

PubMed

el-Nagerabi, S A; Elshafie, A E

2001-01-01

Thirteen seed samples of lentil (Lens esculenta) were incubated on agar plate and moist filter papers (Moist Chambers) at 28 +/- 2 degrees C for determination of the incidence of seed-borne fungi. Aflatoxins content of the seeds was measured using the bright greenish- yellow fluorescence test (BGYF) and thin-layer chromatography (TLC). Sixty-nine species and seven varieties, which belong to 24 genera of fungi, were isolated from this crop. Of these fungi, 51 species and two varieties are considered new for this crop, whereas seven genera and 13 species are new to the mycoflora of the Sudan. The genus Aspergillus (13 species and 6 varieties) which comprising 44% of the total colony count was the most prevalent genus followed by Rhizopus (2 species, 19%), Penicillium (6 species) and Fusarium (8 species) (12%), Chaetomium (3 species) and Cladosporium (5 species) (6%), where the 18 genera (1-4 species) showed very low level of incidence (19%). Of the possible pathogens of lentil plants, F. oxysporum the main cause of vascular wilt was recovered from seeds of this crop. Thin layer chromatographic analysis of chloroform extracts of 13 seed samples showed that only one samples was naturally contaminated with aflatoxins B1, B2, G1 and G2 (14.3 micrograms/kg).

Desiccation tolerance during different desiccation strategies in A. angustifolia embryos

USDA-ARS?s Scientific Manuscript database

Brazilian pine (Araucaria angustifolia) is native to the Atlantic Rainforest of Brazil and is an endangered species. The mature seeds are recalcitrant and have large embryos (about 2.5 cm in length) that contain more than 1 g H2O.g dry mass (dm)-1. Successful cryopreservation requires reduction of ...

The Physiology and Biochemistry of Desiccating White Oak and Cherrybark Oak Acorns

Treesearch

Kristina F. Connor; Sharon Sowa

2004-01-01

The recalcitrant behavior of white oak (Quercus alba L.) and cherrybark oak (Q. pagoda Raf.) acorns was examined in terms of effects of moisture content on seed longevity, viability, and biochemistry. Acorns of both species were fully hydrated and then subjected to drying under ambient conditions of temperature and relative...

7 CFR 948.6 - Seed potatoes.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Seed potatoes. 948.6 Section 948.6 Agriculture... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN COLORADO Order Regulating Handling Definitions § 948.6 Seed potatoes. Seed potatoes or seed means any potatoes...

7 CFR 948.6 - Seed potatoes.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Seed potatoes. 948.6 Section 948.6 Agriculture... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN COLORADO Order Regulating Handling Definitions § 948.6 Seed potatoes. Seed potatoes or seed means any potatoes...

7 CFR 948.6 - Seed potatoes.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Seed potatoes. 948.6 Section 948.6 Agriculture... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN COLORADO Order Regulating Handling Definitions § 948.6 Seed potatoes. Seed potatoes or seed means any potatoes...

7 CFR 948.6 - Seed potatoes.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Seed potatoes. 948.6 Section 948.6 Agriculture... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN COLORADO Order Regulating Handling Definitions § 948.6 Seed potatoes. Seed potatoes or seed means any potatoes...

7 CFR 948.6 - Seed potatoes.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Seed potatoes. 948.6 Section 948.6 Agriculture... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN COLORADO Order Regulating Handling Definitions § 948.6 Seed potatoes. Seed potatoes or seed means any potatoes...

Ultrasonic Percutaneous Tenotomy for Recalcitrant Lateral Elbow Tendinopathy: Sustainability and Sonographic Progression at 3 Years.

PubMed

Seng, Chusheng; Mohan, P Chandra; Koh, Suang Bee Joyce; Howe, Tet Sen; Lim, Yee Gen; Lee, Brian P; Morrey, Bernard F

2016-02-01

percutaneous ultrasonic tenotomy provided sustained pain relief and functional improvement for recalcitrant tennis elbow at 3-year follow-up. It is one of the few procedures to demonstrate positive sonographic evidence of tissue-healing response and is an attractive alternative to surgical intervention for definitive treatment of recalcitrant elbow tendinopathy. © 2015 The Author(s).

Distinct oxidative stabilities of char versus soot black carbon: Implications for quantification and environmental recalcitrance

NASA Astrophysics Data System (ADS)

Elmquist, Marie; Cornelissen, Gerard; Kukulska, Zofia; Gustafsson, Örjan

2006-06-01

Sequestration in sediments of black carbon (BC) from vegetation fires and fuel combustion may constitute a significant sink of otherwise rapidly cycling carbon from the atmosphere-biosphere cycle. It also has the potential to provide a historical record of atmospheric BC loadings. Previous treatments of BC as one homogeneous entity are being replaced with the growing awareness of a BC combustion continuum, a range spanning from slightly charred biomass to soot and graphite. Here the relative recalcitrance of different BC forms is evaluated, and implications for both BC quantification and environmental stability are considered. The stabilities of four BC reference materials against thermal oxidation in air were quite distinct with T50%BC values (i.e., the temperature where 50% BC remained in the residue) of 444°C (diesel soot-BC), 388°C (n-hexane soot-BC), 338°C (wood char-BC), and 266°C (grass char-BC). The implications for BC quantification have been illustrated for a thermal oxidation (the CTO-375) method commonly applied to study BC in sediments. This technique measured BC:TOC ratios of 78.3 ± 1.3% for the diesel soot-BC and 45.3 ± 6.1% for n-hexane soot-BC, whereas no CTO375-BC was detected for the two analyzed char-BC materials. The greater lability of char-BC compared to soot-BC likely reflects higher accessibility to internal microporosity in char-BC, facilitating internal O2 transfer. Decreasing the temperature cutoff below 375°C to also include char-BC is not possible as thermograms of nonpyrogenic reference materials indicated that such material would then be artifactually quantified as BC. The presence of mineral oxides in the sediment matrix may lead to a catalytically mediated lowering of the activation energy for soot-BC oxidation but not for char-BC or nonpyrogenic organic material. Several recent studies combine to challenge the proposition of complete recalcitrance of BC. Particularly, the thermal lability of char-BC from grassland fires

Uncoupling the Effects of Seed Predation and Seed Dispersal by Granivorous Ants on Plant Population Dynamics

PubMed Central

Arnan, Xavier; Molowny-Horas, Roberto; Rodrigo, Anselm; Retana, Javier

2012-01-01

Secondary seed dispersal is an important plant-animal interaction, which is central to understanding plant population and community dynamics. Very little information is still available on the effects of dispersal on plant demography and, particularly, for ant-seed dispersal interactions. As many other interactions, seed dispersal by animals involves costs (seed predation) and benefits (seed dispersal), the balance of which determines the outcome of the interaction. Separate quantification of each of them is essential in order to understand the effects of this interaction. To address this issue, we have successfully separated and analyzed the costs and benefits of seed dispersal by seed-harvesting ants on the plant population dynamics of three shrub species with different traits. To that aim a stochastic, spatially-explicit individually-based simulation model has been implemented based on actual data sets. The results from our simulation model agree with theoretical models of plant response dependent on seed dispersal, for one plant species, and ant-mediated seed predation, for another one. In these cases, model predictions were close to the observed values at field. Nonetheless, these ecological processes did not affect in anyway a third species, for which the model predictions were far from the observed values. This indicates that the balance between costs and benefits associated to secondary seed dispersal is clearly related to specific traits. This study is one of the first works that analyze tradeoffs of secondary seed dispersal on plant population dynamics, by disentangling the effects of related costs and benefits. We suggest analyzing the effects of interactions on population dynamics as opposed to merely analyzing the partners and their interaction strength. PMID:22880125

Impact of heat stress during seed development on soybean seed metabolome

USDA-ARS?s Scientific Manuscript database

Seed development is a temperature-sensitive process that is much more vulnerable than vegetative tissues to abiotic stresses. Climate change is expected to increase the incidence and severity of summer heatwaves, and the impact of heat stress on seed development is expected to become more widespread...

Generalized Two-Dimensional Perturbation Correlation Infrared Spectroscopy reveals Mechanisms for the Development of Surface Charge and Recalcitrance in Plant-derived Biochars

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

Harvey, Omar R.; Herbert, Bruce; Kuo, Li-Jung

2012-09-05

Fundamental knowledge of how biochars develop surface-charge and resistance to environmental degradation (or recalcitrance) is crucial to their production for customized applications or, understanding their functions in the environment. Two-dimensional perturbation-based correlation infrared spectroscopy (2D-PCIS) was used to study the biochar formation process in three taxonomically-different plant biomass, under oxygen-limited conditions along a heat-treatment-temperature gradient (HTT; 200-650 oC). Results from 2D-PCIS pointed to the systematic, HTT-induced defragmenting of lignocellulose H-bonding network, and demethylenation/demethylation, oxidation or dehydroxylation/dehydrogenation of lignocellulose fragments as the primary reactions controlling biochar properties along the HTT gradient. The cleavage of OH O-type H-bonds, oxidation of free primarymore » hydroxyls (HTT≤500 oC), and their subsequent dehydrogenation/dehydroxylation (HTT>500 oC) controlled surface charge on the biochars; while the dehydrogenation of methylene groups, which yielded increasingly condensed structures (R-CH2-R →R=CH-R →R=C=R), controlled biochar recalcitrance. Variations in biochar properties across plant biomass type were attributable to taxa-specific transformations. For example, apparent inefficiencies in the cleavage of wood-specific H-bonds, and their subsequent oxidation to carboxyls, lead to lower surface charge in wood biochars (compared to grass biochars). Both non-taxa and taxa-specific transformations highlighted by 2D-PCIS could have significant implications for biochar functioning in fire-impacted or biochar-amended systems.« less

7 CFR 201.21 - Hard seed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.21 Section 201.21 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21...

7 CFR 201.15 - Weed seeds.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.15...

7 CFR 201.21 - Hard seed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Hard seed. 201.21 Section 201.21 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21...

7 CFR 201.15 - Weed seeds.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.15...

7 CFR 201.21 - Hard seed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Hard seed. 201.21 Section 201.21 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21...

7 CFR 201.21 - Hard seed.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Hard seed. 201.21 Section 201.21 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21...

7 CFR 201.21 - Hard seed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Hard seed. 201.21 Section 201.21 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21...

7 CFR 201.15 - Weed seeds.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.15...

7 CFR 201.15 - Weed seeds.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.15...

7 CFR 201.15 - Weed seeds.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.15...

Estimating Cone and Seed Production and Monitoring Pest Damage in Southern Pine Seed Orchards

Treesearch

Carl W. Fatzinger; H. David Muse; Thomas Miller; Helen T. Bhattacharyya

1988-01-01

Field sampling procedures and computer programs are described for monitoring seed production and pest damage in southern pine seed orchards. The system estimates total orchard yields of female strobili and seeds, quantifies pest damage, determines times of year when losses occur, and produces life tables for female strobili. An example is included to illustrate the...

A Reliable Methodology for Determining Seed Viability by Using Hyperspectral Data from Two Sides of Wheat Seeds.

PubMed

Zhang, Tingting; Wei, Wensong; Zhao, Bin; Wang, Ranran; Li, Mingliu; Yang, Liming; Wang, Jianhua; Sun, Qun

2018-03-08

This study investigated the possibility of using visible and near-infrared (VIS/NIR) hyperspectral imaging techniques to discriminate viable and non-viable wheat seeds. Both sides of individual seeds were subjected to hyperspectral imaging (400-1000 nm) to acquire reflectance spectral data. Four spectral datasets, including the ventral groove side, reverse side, mean (the mean of two sides' spectra of every seed), and mixture datasets (two sides' spectra of every seed), were used to construct the models. Classification models, partial least squares discriminant analysis (PLS-DA), and support vector machines (SVM), coupled with some pre-processing methods and successive projections algorithm (SPA), were built for the identification of viable and non-viable seeds. Our results showed that the standard normal variate (SNV)-SPA-PLS-DA model had high classification accuracy for whole seeds (>85.2%) and for viable seeds (>89.5%), and that the prediction set was based on a mixed spectral dataset by only using 16 wavebands. After screening with this model, the final germination of the seed lot could be higher than 89.5%. Here, we develop a reliable methodology for predicting the viability of wheat seeds, showing that the VIS/NIR hyperspectral imaging is an accurate technique for the classification of viable and non-viable wheat seeds in a non-destructive manner.

Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions

PubMed Central

Groot, S. P. C.; Surki, A. A.; de Vos, R. C. H.; Kodde, J.

2012-01-01

Background and Aims Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. Methods Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. Key Results The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Conclusions Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice. PMID:22967856

Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions.

PubMed

Groot, S P C; Surki, A A; de Vos, R C H; Kodde, J

2012-11-01

Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. methods: Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice.

[Seed geography: its concept and basic scientific issues].

PubMed

Yu, Shun-Li; Wang, Zong-Shuai; Zeren, Wangmu

2010-01-01

In this paper, a new concept 'seed geography' was provided, and its definition, research contents, and scientific issues were put forward. Seed geography is a newly developed interdisciplinary science from plant geography, seed ecology, and phytosociology, which studies the geographic variation patterns of seed biological traits as well as their relationships with environmental factors from macroscopic to microscopic, and the seed formation, development, and change trends. The main research contents would include geography of seed mass, geography of seed chemical components, geography of seed morphology, geography of seed cell biological characteristics, geography of seed physiological characteristics, geography of seed genetic characteristics, and geography of flower and fruit. To explore the scientific issues in seed geography would help us to better understand the long-term adaptation and evolution of seed characteristics to natural environments.

Impact of Restoration of Soil in a Humid Tropical Region on Storage of Organic Carbon in a Recalcitrant Pool

NASA Astrophysics Data System (ADS)

Jyoti Nath, Arun; Brahma, Biplab; Lal, Rattan; Das, Ashesh Kumar

2017-04-01

Quantifying soil organic carbon (SOC) changes through restoration of degraded lands is important to assessing the changes in soil properties. However, SOC measures all C fractions and its assessment is not adequate to distinguish between the more dynamic or active C (AC) fractions and the recalcitrant or passive C (PC) form. SOC fractions comprising of the recalcitrant pools have been suggested as a driver for long term soil C sink management. Therefore, the present study was undertaken at a site within the North Eastern India (NEI) region with an objective to explore whether or not SOC fractions change with restoration of degraded lands under humid tropical climate. An age-chronosequence study was established comprising of four different aged rubber plantations (6, 15, 27 and 34 yr. old) planted on Imperata grasslands. The site was selected to study changes in the different fractions of SOC and total SOC stock, and the data were compared with that of a native forest. The data indicated that the SOC stock increased from 106 Mg ha-1 under 6 yr. to 130 Mg ha-1 under 34 yr. old plantations. The SOC stock after 34 yr. of plantation was 20% higher than that under Imperata grassland, but was 34% lower than that under the native forest soil. With respect to lability of C fractions, proportion of AC pool decreased linearly with increase in plantation age from 59 % under 6 yr to 33 % under 34 yr. old plantations. In contrast, proportion of PC pool increased from 41 % of SOC stock under 6 yr. to 67 % of SOC under 34 yr. old plantations, suggesting the significant role of old aged plantation in C sink management.

Optimum harvest maturity for Leymus chinensis seed.

PubMed

Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui; Mu, Chunsheng

2016-06-15

Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. © 2016. Published by The Company of Biologists Ltd.

Optimum harvest maturity for Leymus chinensis seed

PubMed Central

Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui

2016-01-01

ABSTRACT Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. PMID:27170257

7 CFR 201.30 - Hard seed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Hard seed. 201.30 Section 201.30 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard...

7 CFR 201.30 - Hard seed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Hard seed. 201.30 Section 201.30 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard...

7 CFR 201.30 - Hard seed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.30 Section 201.30 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard...

7 CFR 201.30 - Hard seed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Hard seed. 201.30 Section 201.30 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard...

7 CFR 201.30 - Hard seed.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Hard seed. 201.30 Section 201.30 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard...

Recent trends in post-wildfire seeding in western US forests: costs and seed mixes

Treesearch

Donna L. Peppin; Peter Z. Fule; Carolyn Hull Sieg; Jan L. Beyers; Molly E. Hunter; Pete Robichaud

2011-01-01

Broadcast seeding is one of the most commonly used post-fire rehabilitation treatments to establish ground cover for erosion control and mitigation of non-native plant species invasions. Little quantitative information is available on overall trends of post-fire seeding expenditures and seed mixes used over time in forested ecosystems in the western USA. We reviewed...

Evaluation of water binding, seed coat permeability and germination characteristics of wheat seeds equilibrated at different relative humidities.

PubMed

Chatterjee, Nabamita; Nagarajan, Shantha

2006-08-01

The relative binding of seed water and seed coat membrane stability were measured in two contrasting wheat (Triticum aestivum L) varieties, HDR 77 (drought-tolerant) and HD 2009 (susceptible) using seed water sorption isotherms, electrical conductivity (EC) of leachates and desorption-absorption isotherms. Analysis of sorption isotherm at 25 degrees C showed that the seeds of HDR 77 had significantly higher number of strong binding sites, with correspondingly greater amount of seed water as strongly bound water, as compared to HD 2009. Total number of binding sites was also higher in HDR 77 than HD 2009, which explained the better desiccation tolerance and higher capacity to bind water in seeds of HDR 77. EC of seed leachate in both varieties did not change with respect to change in equilibrium relative humidity (RII), indicating the general seed coat membrane stability of wheat seeds. However, absolute conductivity values were higher for HD 2009. showing its relatively porous seed coat membrane. Significantly lower area enclosed by the desorption-absorption isotherm loop in HDR 77, as compared to HD 2009 also indicated the greater membrane integrity of HDR 77. Germination and seedling vigour of HD 2009 were reduced when equilibrated over very low and very high RH. In contrast, germination and vigour in HDR 77 were maintained high, except at very high RH, indicating again its desiccation tolerance. Thus, the study demonstrated the relative drought tolerance of HDR 77, on the basis of seed water-binding characteristics and seed membrane stability. Seed membrane stability as measured by seed leachate conductivity or as area under dehydration-rehydration loop may be used as a preliminary screening test for drought tolerance in wheat.

Tolerance of Ruppia sinensis Seeds to Desiccation, Low Temperature, and High Salinity With Special Reference to Long-Term Seed Storage.

PubMed

Gu, Ruiting; Zhou, Yi; Song, Xiaoyue; Xu, Shaochun; Zhang, Xiaomei; Lin, Haiying; Xu, Shuai; Yue, Shidong; Zhu, Shuyu

2018-01-01

Seeds are important materials for the restoration of globally-threatened marine angiosperm (seagrass) populations. In this study, we investigated the differences between different Ruppia sinensis seed types and developed two feasible long-term R. sinensis seed storage methods. The ability of R. sinensis seeds to tolerate the short-term desiccation and extreme cold had been investigated. The tolerance of R. sinensis seeds to long-term exposure of high salinity, cold temperature, and desiccation had been considered as potential methods for long-term seed storage. Also, three morphological and nine physiological indices were measured and compared between two types of seeds: Shape L and Shape S. We found that: (1) wet storage at a salinity of 30-40 psu and 0°C were the optimal long-term storage conditions, and the proportion of viable seeds reached over 90% after a storage period of 11 months since the seeds were collected from the reproductive shoots; (2) dry condition was not the optimal choice for long-term storage of R. sinensis seeds; however, storing seeds in a dry condition at 5°C and 33 ± 10% relative humidity for 9 months had a relatively high percentage (74.44 ± 2.22%) of viable seeds, consequently desiccation exposure could also be an acceptable seed storage method; (3) R. sinensis seeds would lose vigor in the interaction of extreme cold (-27°C) and desiccation; (4) there were significant differences in seed weight, seed curvature, and endocarp thickness between the two types of seeds. These findings provided fundamental physiological information for R. sinensis seeds and supported the long-term storage of its seeds. Our results may also serve as useful reference for seed storage of other threatened seagrass species and facilitate their ex situ conservation and habitat restoration.

Seeds of change: corn seed mixtures for resistance management and IPM

USDA-ARS?s Scientific Manuscript database

The use of mixtures of insecticidal seed and non-toxic seed to provide an in-field refuge for susceptible insects in an insect-resistance-management (IRM) plan has been considered for at least two decades, but the US Environmental Protection Agency has only recently authorized their use in commercia...

Seed removal in a tropical North American desert: an evaluation of pre- and post-dispersal seed removal in Stenocereus stellatus.

PubMed

Álvarez-Espino, R; Ríos-Casanova, L; Godínez-Álvarez, H

2017-05-01

To determine seed removal influence on seed populations, we need to quantify pre- and post-dispersal seed removal. Several studies have quantified seed removal in temperate American deserts, but few studies have been performed in tropical deserts. These studies have only quantified pre- or post-dispersal seed removal, thus underestimating the influence of seed removal. We evaluated pre- and post-dispersal seed removal in the columnar cactus Stenocereus stellatus in a Mexican tropical desert. We performed selective exclosure experiments to estimate percentage of seeds removed by ants, birds and rodents during the pre- and post-dispersal phases. We also conducted field samplings to estimate abundance of the most common seed removers. Birds (10-28%) removed a higher percentage of seeds than ants (2%) and rodents (1-4%) during pre-dispersal seed removal. Melanerpes hypopolius was probably the main bird removing seeds from fruits. Ants (62-64%) removed a higher percentage of seeds than birds (34-38%) and rodents (16-30%) during post-dispersal seed removal. Pogonomyrmex barbatus was probably the main ant removing seeds from soil. Birds and ants are the main pre- and post-dispersal seed removers in S. stellatus, respectively. Further studies in other S. stellatus populations and plants with different life forms and fruit types will contribute to evaluate seed removal in tropical American deserts. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Efficacy of the apitherapy in the treatment of recalcitrant localized plaque psoriasis and evaluation of tumor necrosis factor-alpha (TNF-α) serum level: A double-blind randomized clinical trial.

PubMed

Eltaher, Soha; Mohammed, Ghada F; Younes, Soha; Elakhras, Atef

2015-01-01

No universal consensus about optimal modality for treating the recalcitrant localized plaque psoriasis (RLPP) is available. To evaluate the immunological and clinical therapeutic effect of using apitherapy in the treatment of RLPP. Randomized 50 patients with RLPP received apitherapy (n = 25) and placebo (n = 25) every week. Both treatments were injected into lesions at weekly intervals for a maximum of 12 treatments. Following up was 6 months later. Tumor necrosis factor-alpha (TNF-α) level was measured at pre-study and at 12th week. A significant difference was found between the therapeutic responses of RLPP to the apitherapy and placebo groups (p<0.001). In the apitherapy group, complete response was achieved in 92% of patients. There was statistically significant decrease in TNF-α in the apitherapy group compared to the placebo group. No recurrence was observed in the apitherapy group. Apitherapy is effective and a safe treatment for recalcitrant localized plaque psoriasis, when other topical or physical therapies have failed.

Ecosystem services from keystone species: diversionary seeding and seed-caching desert rodents can enhance Indian ricegrass seedling establishment

USGS Publications Warehouse

Longland, William; Ostoja, Steven M.

2013-01-01

Seeds of Indian ricegrass (Achnatherum hymenoides), a native bunchgrass common to sandy soils on arid western rangelands, are naturally dispersed by seed-caching rodent species, particularly Dipodomys spp. (kangaroo rats). These animals cache large quantities of seeds when mature seeds are available on or beneath plants and recover most of their caches for consumption during the remainder of the year. Unrecovered seeds in caches account for the vast majority of Indian ricegrass seedling recruitment. We applied three different densities of white millet (Panicum miliaceum) seeds as “diversionary foods” to plots at three Great Basin study sites in an attempt to reduce rodents' over-winter cache recovery so that more Indian ricegrass seeds would remain in soil seedbanks and potentially establish new seedlings. One year after diversionary seed application, a moderate level of Indian ricegrass seedling recruitment occurred at two of our study sites in western Nevada, although there was no recruitment at the third site in eastern California. At both Nevada sites, the number of Indian ricegrass seedlings sampled along transects was significantly greater on all plots treated with diversionary seeds than on non-seeded control plots. However, the density of diversionary seeds applied to plots had a marginally non-significant effect on seedling recruitment, and it was not correlated with recruitment patterns among plots. Results suggest that application of a diversionary seed type that is preferred by seed-caching rodents provides a promising passive restoration strategy for target plant species that are dispersed by these rodents.

Contagious Deposition of Seeds in Spider Monkeys' Sleeping Trees Limits Effective Seed Dispersal in Fragmented Landscapes

PubMed Central

González-Zamora, Arturo; Arroyo-Rodríguez, Víctor; Escobar, Federico; Rös, Matthias; Oyama, Ken; Ibarra-Manríquez, Guillermo; Stoner, Kathryn E.; Chapman, Colin A.

2014-01-01

The repeated use of sleeping sites by frugivorous vertebrates promotes the deposition and aggregation of copious amounts of seeds in these sites. This spatially contagious pattern of seed deposition has key implications for seed dispersal, particularly because such patterns can persist through recruitment. Assessing the seed rain patterns in sleeping sites thus represents a fundamental step in understanding the spatial structure and regeneration of plant assemblages. We evaluated the seed rain produced by spider monkeys (Ateles geoffroyi) in latrines located beneath 60 sleeping trees in two continuous forest sites (CFS) and three forest fragments (FF) in the Lacandona rainforest, Mexico. We tested for differences among latrines, among sites, and between forest conditions in the abundance, diversity (α-, β- and, γ-components) and evenness of seed assemblages. We recorded 45,919 seeds ≥5 mm (in length) from 68 species. The abundance of seeds was 1.7 times higher in FF than in CFS, particularly because of the dominance of a few plant species. As a consequence, community evenness tended to be lower within FF. β-diversity of common and dominant species was two times greater among FF than between CFS. Although mean α-diversity per latrine did not differ among sites, the greater β-diversity among latrines in CFS increased γ-diversity in these sites, particularly when considering common and dominant species. Our results support the hypothesis that fruit scarcity in FF can ‘force’ spider monkeys to deplete the available fruit patches more intensively than in CFS. This feeding strategy can limit the effectiveness of spider monkeys as seed dispersers in FF, because (i) it can limit the number of seed dispersers visiting such fruit patches; (ii) it increases seed dispersal limitation; and (iii) it can contribute to the floristic homogenization (i.e., reduced β-diversity among latrines) in fragmented landscapes. PMID:24586705

Abscisic Acid Levels and Seed Dormancy

PubMed Central

Sondheimer, E.; Tzou, D. S.; Galson, Eva C.

1968-01-01

Dormant seeds from Fraxinus species require cold-temperature after-ripening prior to germination. Earlier, we found that abscisic acid (ABA) will inhibit germination of excised nondormant embryos and that this can be reversed with a combination of gibberellic acid and kinetin. Using Milborrow's quantitative “racemate dilution” method the ABA concentration in 3 types of Fraxinus seed and pericarp were determined. While ABA was present in all tissues, the highest concentration was found in the seed and pericarp of dormant F. americana. During the chilling treatment of F. americana the ABA levels decreased 37% in the pericarp and 68% in the seed. The ABA concentration of the seed of the nondormant species, F. ornus, is as low as that found in F. americana seeds after cold treatment. Experiments with exogenously added ABA solutions indicate that it is unlikely that the ABA in the pericarp functions in the regulation of seed dormancy. However, the ABA in the seed does seem to have a regulatory role in germination. Images PMID:16656935