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Sample records for abiotic factors including

  1. The impact of abiotic factors on cellulose synthesis.

    PubMed

    Wang, Ting; McFarlane, Heather E; Persson, Staffan

    2016-01-01

    As sessile organisms, plants require mechanisms to sense and respond to changes in their environment, including both biotic and abiotic factors. One of the most common plant adaptations to environmental changes is differential regulation of growth, which results in growth either away from adverse conditions or towards more favorable conditions. As cell walls shape plant growth, this differential growth response must be accompanied by alterations to the plant cell wall. Here, we review the impact of four abiotic factors (osmotic conditions, ionic stress, light, and temperature) on the synthesis of cellulose, an important component of the plant cell wall. Understanding how different abiotic factors influence cellulose production and addressing key questions that remain in this field can provide crucial information to cope with the need for increased crop production under the mounting pressures of a growing world population and global climate change.

  2. Biotic and abiotic factors predicting the global distribution and population density of an invasive large mammal

    PubMed Central

    Lewis, Jesse S.; Farnsworth, Matthew L.; Burdett, Chris L.; Theobald, David M.; Gray, Miranda; Miller, Ryan S.

    2017-01-01

    Biotic and abiotic factors are increasingly acknowledged to synergistically shape broad-scale species distributions. However, the relative importance of biotic and abiotic factors in predicting species distributions is unclear. In particular, biotic factors, such as predation and vegetation, including those resulting from anthropogenic land-use change, are underrepresented in species distribution modeling, but could improve model predictions. Using generalized linear models and model selection techniques, we used 129 estimates of population density of wild pigs (Sus scrofa) from 5 continents to evaluate the relative importance, magnitude, and direction of biotic and abiotic factors in predicting population density of an invasive large mammal with a global distribution. Incorporating diverse biotic factors, including agriculture, vegetation cover, and large carnivore richness, into species distribution modeling substantially improved model fit and predictions. Abiotic factors, including precipitation and potential evapotranspiration, were also important predictors. The predictive map of population density revealed wide-ranging potential for an invasive large mammal to expand its distribution globally. This information can be used to proactively create conservation/management plans to control future invasions. Our study demonstrates that the ongoing paradigm shift, which recognizes that both biotic and abiotic factors shape species distributions across broad scales, can be advanced by incorporating diverse biotic factors. PMID:28276519

  3. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses.

    PubMed

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention.

  4. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses

    PubMed Central

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention. PMID:26904076

  5. AP2/ERF family transcription factors in plant abiotic stress responses.

    PubMed

    Mizoi, Junya; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2012-02-01

    In terrestrial environments, temperature and water conditions are highly variable, and extreme temperatures and water conditions affect the survival, growth and reproduction of plants. To protect cells and sustain growth under such conditions of abiotic stress, plants respond to unfavourable changes in their environments in developmental, physiological and biochemical ways. These responses require expression of stress-responsive genes, which are regulated by a network of transcription factors. The AP2/ERF family is a large family of plant-specific transcription factors that share a well-conserved DNA-binding domain. This transcription factor family includes DRE-binding proteins (DREBs), which activate the expression of abiotic stress-responsive genes via specific binding to the dehydration-responsive element/C-repeat (DRE/CRT) cis-acting element in their promoters. In this review, we discuss the functions of the AP2/ERF-type transcription factors in plant abiotic stress responses, with special emphasis on the regulations and functions of two major types of DREBs, DREB1/CBF and DREB2. In addition, we summarise the involvement of other AP2/ERF-type transcription factors in abiotic stress responses, which has recently become clear. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress.

  6. Structure, function and networks of transcription factors involved in abiotic stress responses.

    PubMed

    Lindemose, Søren; O'Shea, Charlotte; Jensen, Michael Krogh; Skriver, Karen

    2013-03-13

    Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic disorder (ID), referring to their lack of fixed tertiary structures. ID is now an emerging topic in plant science. Furthermore, the importance of the ubiquitin-proteasome protein degradation systems and modification by sumoylation is also apparent from the interactomes. Therefore; TF interaction partners such as E3 ubiquitin ligases and TF regions with ID represent future targets for engineering improved abiotic stress tolerance in crops.

  7. Soil abiotic factors influence interactions between belowground herbivores and plant roots.

    PubMed

    Erb, Matthias; Lu, Jing

    2013-03-01

    Root herbivores are important ecosystem drivers and agricultural pests, and, possibly as a consequence, plants protect their roots using a variety of defensive strategies. One aspect that distinguishes belowground from aboveground plant-insect interactions is that roots are constantly exposed to a set of soil-specific abiotic factors. These factors can profoundly influence root resistance, and, consequently, the outcome of the interaction with belowground feeders. In this review, we synthesize the current literature on the impact of soil moisture, nutrients, and texture on root-herbivore interactions. We show that soil abiotic factors influence the interaction by modulating herbivore abundance and behaviour, root growth and resistance, beneficial microorganisms, as well as natural enemies of the herbivores. We suggest that abiotic heterogeneity may explain the high variability that is often encountered in root-herbivore systems. We also propose that under abiotic stress, the relative fitness value of the roots and the potential negative impact of herbivory increases, which may lead to a higher defensive investment and an increased recruitment of beneficial microorganisms by the plant. At the same time, both root-feeding herbivores and natural enemies are likely to decrease in abundance under extreme environmental conditions, leading to a context- and species-specific impact on plant fitness. Only by using tightly controlled experiments that include soil abiotic heterogeneity will it be possible to understand the impact of root feeders on an ecosystem scale and to develop predictive models for pest occurrence and impact.

  8. Influence of abiotic factors on the antimicrobial activity of chitosan.

    PubMed

    Tavaria, Freni K; Costa, Eduardo M; Gens, Eduardo J; Malcata, Francisco Xavier; Pintado, Manuela E

    2013-12-01

    In an effort to bypass the adverse secondary effects attributed to the traditional therapeutic approaches used to treat skin disorders (such as atopic dermatitis), alternative antimicrobials have recently been suggested. One such antimicrobial is chitosan, owing to the already proved biological properties associated with its use. However, the influence of abiotic factors on such activities warrants evaluation. This research effort assessed the antimicrobial activity of chitosan upon skin microorganisms (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) in vitro when subject to a combination of different abiotic factors such as pH, ionic strength, organic acids and free fatty acids. Free fatty acids, ionic strength and pH significantly affected chitosan's capability of reducing the viable numbers of S. aureus. This antimicrobial action was potentiated in the presence of palmitic acid and a lower ionic strength (0.2% NaCl), while a higher ionic strength (0.4% NaCl) favored chitosan's action upon the reduction of viable numbers of S. epidermidis and E. coli. Although further studies are needed, these preliminary results advocate that chitosan can in the future be potentially considered as an antimicrobial of choice when handling symptoms associated with atopic dermatitis.

  9. Abiotic factors influence plant storage lipid accumulation and composition.

    PubMed

    Singer, Stacy D; Zou, Jitao; Weselake, Randall J

    2016-02-01

    The demand for plant-derived oils has increased substantially over the last decade, and is sure to keep growing. While there has been a surge in research efforts to produce plants with improved oil content and quality, in most cases the enhancements have been small. To add further complexity to this situation, substantial differences in seed oil traits among years and field locations have indicated that plant lipid biosynthesis is also influenced to a large extent by multiple environmental factors such as temperature, drought, light availability and soil nutrients. On the molecular and biochemical levels, the expression and/or activities of fatty acid desaturases, as well as diacylglycerol acyltransferase 1, have been found to be affected by abiotic factors, suggesting that they play a role in the lipid content and compositional changes seen under abiotic stress conditions. Unfortunately, while only a very small number of strategies have been developed as of yet to minimize these environmental effects on the production of storage lipids, it is clear that this feat will be of the utmost importance for developing superior oil crops with the capability to perform in a consistent manner in field conditions in the future.

  10. Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids

    PubMed Central

    Becker, Christine; Desneux, Nicolas; Monticelli, Lucie; Fernandez, Xavier; Michel, Thomas; Lavoir, Anne-Violette

    2015-01-01

    In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and “green leaf volatiles.” Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant's growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change. PMID:26788501

  11. Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids.

    PubMed

    Becker, Christine; Desneux, Nicolas; Monticelli, Lucie; Fernandez, Xavier; Michel, Thomas; Lavoir, Anne-Violette

    2015-01-01

    In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and "green leaf volatiles." Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant's growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change.

  12. The transcriptional regulatory network in the drought response and its crosstalk in abiotic stress responses including drought, cold, and heat

    PubMed Central

    Nakashima, Kazuo; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo

    2014-01-01

    Drought negatively impacts plant growth and the productivity of crops around the world. Understanding the molecular mechanisms in the drought response is important for improvement of drought tolerance using molecular techniques. In plants, abscisic acid (ABA) is accumulated under osmotic stress conditions caused by drought, and has a key role in stress responses and tolerance. Comprehensive molecular analyses have shown that ABA regulates the expression of many genes under osmotic stress conditions, and the ABA-responsive element (ABRE) is the major cis-element for ABA-responsive gene expression. Transcription factors (TFs) are master regulators of gene expression. ABRE-binding protein and ABRE-binding factor TFs control gene expression in an ABA-dependent manner. SNF1-related protein kinases 2, group A 2C-type protein phosphatases, and ABA receptors were shown to control the ABA signaling pathway. ABA-independent signaling pathways such as dehydration-responsive element-binding protein TFs and NAC TFs are also involved in stress responses including drought, heat, and cold. Recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress responses. The important roles of these TFs in crosstalk among abiotic stress responses will be discussed. Control of ABA or stress signaling factor expression can improve tolerance to environmental stresses. Recent studies using crops have shown that stress-specific overexpression of TFs improves drought tolerance and grain yield compared with controls in the field. PMID:24904597

  13. NAC transcription factors in plant multiple abiotic stress responses: progress and prospects

    PubMed Central

    Shao, Hongbo; Wang, Hongyan; Tang, Xiaoli

    2015-01-01

    Abiotic stresses adversely affect plant growth and agricultural productivity. According to the current climate prediction models, crop plants will face a greater number of environmental stresses, which are likely to occur simultaneously in the future. So it is very urgent to breed broad-spectrum tolerant crops in order to meet an increasing demand for food productivity due to global population increase. As one of the largest families of transcription factors (TFs) in plants, NAC TFs play vital roles in regulating plant growth and development processes including abiotic stress responses. Lots of studies indicated that many stress-responsive NAC TFs had been used to improve stress tolerance in crop plants by genetic engineering. In this review, the recent progress in NAC TFs was summarized, and the potential utilization of NAC TFs in breeding abiotic stress tolerant transgenic crops was also be discussed. In view of the complexity of field conditions and the specificity in multiple stress responses, we suggest that the NAC TFs commonly induced by multiple stresses should be promising candidates to produce plants with enhanced multiple stress tolerance. Furthermore, the field evaluation of transgenic crops harboring NAC genes, as well as the suitable promoters for minimizing the negative effects caused by over-expressing some NAC genes, should be considered. PMID:26579152

  14. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (hymenoptera: bethylidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we examined the effects of biotic and abiotic factors including temperature, photoperiod, light intensity,...

  15. Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation

    PubMed Central

    Agler, Matthew T.; Ruhe, Jonas; Kroll, Samuel; Morhenn, Constanze; Kim, Sang-Tae; Weigel, Detlef; Kemen, Eric M.

    2016-01-01

    Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe–microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe–microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial “hubs,” are strongly interconnected and have a severe effect on communities. By documenting these microbe–microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on “hub” microbes, which, via microbe–microbe interactions, transmit the effects to the microbial community. We analyzed two “hub” microbes (the

  16. The NAC family transcription factor OsNAP confers abiotic stress response through the ABA pathway.

    PubMed

    Chen, Xu; Wang, Yaofeng; Lv, Bo; Li, Jie; Luo, Liqiong; Lu, Songchong; Zhang, Xuan; Ma, Hong; Ming, Feng

    2014-03-01

    Plants respond to environmental stresses by altering gene expression, and several genes have been found to mediate stress-induced expression, but many additional factors are yet to be identified. OsNAP is a member of the NAC transcription factor family; it is localized in the nucleus, and shows transcriptional activator activity in yeast. Analysis of the OsNAP transcript levels in rice showed that this gene was significantly induced by ABA and abiotic stresses, including high salinity, drought and low temperature. Rice plants overexpressing OsNAP did not show growth retardation, but showed a significantly reduced rate of water loss, enhanced tolerance to high salinity, drought and low temperature at the vegetative stage, and improved yield under drought stress at the flowering stage. Microarray analysis of transgenic plants overexpressing OsNAP revealed that many stress-related genes were up-regulated, including OsPP2C06/OsABI2, OsPP2C09, OsPP2C68 and OsSalT, and some genes coding for stress-related transcription factors (OsDREB1A, OsMYB2, OsAP37 and OsAP59). Our data suggest that OsNAP functions as a transcriptional activator that plays a role in mediating abiotic stress responses in rice.

  17. Explicit modeling of abiotic and landscape factors reveals precipitation and forests associated with aphid abundance.

    PubMed

    Stack Whitney, Kaitlin; Meehan, Timothy D; Kucharik, Christopher J; Zhu, Jun; Townsend, Philip A; Hamilton, Krista; Gratton, Claudio

    2016-12-01

    Increases in natural or noncrop habitat surrounding agricultural fields have been shown to be correlated with declines in insect crop pests. However, these patterns are highly variable across studies suggesting other important factors, such as abiotic drivers, which are rarely included in landscape models, may also contribute to variability in insect population abundance. The objective of this study was to explicitly account for the contribution of temperature and precipitation, in addition to landscape composition, on the abundance of a widespread insect crop pest, the soybean aphid (Aphis glycines Matsumura), in Wisconsin soybean fields. We hypothesized that higher soybean aphid abundance would be associated with higher heat accumulation (e.g., growing degree days) and increasing noncrop habitat in the surrounding landscape, due to the presence of the overwintering primary hosts of soybean aphid. To evaluate these hypotheses, we used an ecoinformatics approach that relied on a large dataset collected across Wisconsin over a 9-year period (2003-2011), for an average of 235 sites per year (n = 2,110 fields total). We determined surrounding landscape composition (1.5-km radius) using publicly available satellite-derived land cover imagery and interpolated daily temperature and precipitation information from the National Weather Service COOP weather station network. We constructed linear mixed models for soybean aphid abundance based on abiotic and landscape explanatory variables and applied model averaging for prediction using an information theoretic framework. Over this broad spatial and temporal extent in Wisconsin, we found that variation in growing season precipitation was positively related to soybean aphid abundance, while higher precipitation during the nongrowing season had a negative effect on aphid populations. Additionally, we found that aphid populations were higher in areas with proportionally more forest but were lower in areas where minor crops

  18. [Relationship between antophyte foliar morphology and abiotic factors in the main rainforests of Eastern Cuba].

    PubMed

    Quesada, Eddy Martínez

    2009-01-01

    Relationship between antophyte foliar morphology and abiotic factors in the main rainforests of Eastern Cuba. The foliar morphology of representative antophytes in four rainforest types of Eastern Cuba was studied in relation to the main abiotic factors. Although there are several leaf types in these forests, the microphyll type is the most important among endemic species in the ophiolites complex and the Montane rainforest. At the Lowland rainforest (metamorphic complex) the mesophyll leaf was the most important. Most foliar epidermis had structures normally found in mesomorphic plants, but xeromorphic and higromorphic morphologies were also present.

  19. Comprehensive analysis suggests overlapping expression of rice ONAC transcription factors in abiotic and biotic stress responses.

    PubMed

    Sun, Lijun; Huang, Lei; Hong, Yongbo; Zhang, Huijuan; Song, Fengming; Li, Dayong

    2015-02-17

    NAC (NAM/ATAF/CUC) transcription factors comprise a large plant-specific gene family that contains more than 149 members in rice. Extensive studies have revealed that NAC transcription factors not only play important roles in plant growth and development, but also have functions in regulation of responses to biotic and abiotic stresses. However, biological functions for most of the members in the NAC family remain unknown. In this study, microarray data analyses revealed that a total of 63 ONAC genes exhibited overlapping expression patterns in rice under various abiotic (salt, drought, and cold) and biotic (infection by fungal, bacterial, viral pathogens, and parasitic plants) stresses. Thirty-eight ONAC genes exhibited overlapping expression in response to any two abiotic stresses, among which 16 of 30 selected ONAC genes were upregulated in response to exogenous ABA. Sixty-five ONAC genes showed overlapping expression patterns in response to any two biotic stresses. Results from the present study suggested that members of the ONAC genes with overlapping expression pattern may have pleiotropic biological functions in regulation of defense response against different abiotic and biotic stresses, which provide clues for further functional analysis of the ONAC genes in stress tolerance and pathogen resistance.

  20. Influence of intraspecific variability and abiotic factors on mycotoxin production in Penicillium roqueforti.

    PubMed

    Fontaine, Kévin; Hymery, Nolwenn; Lacroix, Marlène Z; Puel, Sylvie; Puel, Olivier; Rigalma, Karim; Gaydou, Vincent; Coton, Emmanuel; Mounier, Jérôme

    2015-12-23

    Penicillium roqueforti has the ability to produce secondary metabolites, including roquefortine C (ROQC) and mycophenolic acid (MPA). In a previous study, the presence of these mycotoxins, alone or in co-occurrence, has been reported in blue-veined cheese. A high variability of mycotoxin content has also been observed, although the majority of samples exhibited relatively low concentrations. The observed variability raises the question of the factors impacting ROQC and MPA production. In this context, the mycotoxigenic potential of 96 P. roqueforti strains (biotic factor) and the effect of some abiotic factors (pH, temperature, NaCl and O2 contents, and C/N ratio) on mycotoxin production were evaluated. A high intraspecific diversity, established via genotypic (RAPD) and phenotypic (FTIR) approaches, was observed. It was associated with mycotoxigenic potential variability and may thus explain part of the observed variability in mycotoxin content of blue-veined cheese. Moreover, a significant decrease of ROQC and MPA production was observed for conditions (temperature, C/N ratio, O2 and NaCl concentrations) encountered during cheese-making compared with optimal growth conditions. The results also highlighted that there was no significant effect of addition of ROQC amino-acid precursor on the production of both mycotoxins whereas a pH increase from 4.5 to 6.5 slightly reduced MPA but not ROQC production.

  1. Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

    NASA Astrophysics Data System (ADS)

    Yang, Zhen; Kong, Fanxiang

    2013-07-01

    Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

  2. Abiotic Factors Shape Microbial Diversity in Sonoran Desert Soils

    PubMed Central

    Fitak, Robert R.; Munguia-Vega, Adrian; Racolta, Adriana; Martinson, Vincent G.; Dontsova, Katerina

    2012-01-01

    High-throughput, culture-independent surveys of bacterial and archaeal communities in soil have illuminated the importance of both edaphic and biotic influences on microbial diversity, yet few studies compare the relative importance of these factors. Here, we employ multiplexed pyrosequencing of the 16S rRNA gene to examine soil- and cactus-associated rhizosphere microbial communities of the Sonoran Desert and the artificial desert biome of the Biosphere2 research facility. The results of our replicate sampling approach show that microbial communities are shaped primarily by soil characteristics associated with geographic locations, while rhizosphere associations are secondary factors. We found little difference between rhizosphere communities of the ecologically similar saguaro (Carnegiea gigantea) and cardón (Pachycereus pringlei) cacti. Both rhizosphere and soil communities were dominated by the disproportionately abundant Crenarchaeota class Thermoprotei, which comprised 18.7% of 183,320 total pyrosequencing reads from a comparatively small number (1,337 or 3.7%) of the 36,162 total operational taxonomic units (OTUs). OTUs common to both soil and rhizosphere samples comprised the bulk of raw sequence reads, suggesting that the shared community of soil and rhizosphere microbes constitute common and abundant taxa, particularly in the bacterial phyla Proteobacteria, Actinobacteria, Planctomycetes, Firmicutes, Bacteroidetes, Chloroflexi, and Acidobacteria. The vast majority of OTUs, however, were rare and unique to either soil or rhizosphere communities and differed among locations dozens of kilometers apart. Several soil properties, particularly soil pH and carbon content, were significantly correlated with community diversity measurements. Our results highlight the importance of culture-independent approaches in surveying microbial communities of extreme environments. PMID:22885757

  3. Buccal pumping mechanics of Xenopus laevis tadpoles: effects of biotic and abiotic factors.

    PubMed

    Ryerson, William G; Deban, Stephen M

    2010-07-15

    Biotic factors such as body size and shape have long been known to influence kinematics in vertebrates. Movement in aquatic organisms can also be strongly affected by abiotic factors such as the viscosity of the medium. We examined the effects of both biotic factors and abiotic factors on buccal pumping kinematics in Xenopus tadpoles using high-speed imaging of an ontogenetic series of tadpoles combined with experimental manipulation of the medium over a 10-fold range of viscosity. We found influences of both biotic and abiotic factors on tadpole movements; absolute velocities and excursions of the jaws and hyoid were greater in higher viscosity fluid but durations of movements were unaffected. Smaller tadpoles have relatively wider heads and more robust hyoid muscles used in buccal expansion and compression. Lever arm ratios were found to be constant at all sizes; therefore, smaller tadpoles have relatively higher resolved muscle forces and, like tadpoles in more viscous medium, displayed higher absolute velocities of jaw and hyoid movements. Nonetheless, small tadpoles drew in water at lower Reynolds numbers (Re) than predicted by kinematics, due to negative allometry of the buccal pump. Finally, tadpoles transitioned from a flow regime dominated by viscous forces (Re=2) to an intermediate regime (Re=106).

  4. Distribution of the Euryhaline Squid Lolliguncula brevis in Chesapeake Bay: Effects of Selected Abiotic Factors

    DTIC Science & Technology

    2002-01-31

    significant aquatic habitats where cephalopods are poorly represented. One notable squid, the brief squid Lolliguncula brevis, is the only species of... cephalopod frequently found in low-salinity estuaries (Vecchione 1991a), where it tolerates salinities as low as 8.5‰ for brief periods (Laughlin...effects of selected abiotic factors I. K. Bartol1,*, R. Mann2, M. Vecchione3 1Department of Organismic Biology, Ecology, and Evolution , University of

  5. DREB1/CBF transcription factors: their structure, function and role in abiotic stress tolerance in plants.

    PubMed

    Akhtar, M; Jaiswal, A; Taj, G; Jaiswal, J P; Qureshi, M I; Singh, N K

    2012-01-01

    Drought, high salinity and low temperature are major abiotic stresses that influence survival, productivity and geographical distribution of many important crops across the globe. Plants respond to these environmental challenges via physiological, cellular and molecular processes, which results in adjusted metabolic and structural alterations. The dehydration-responsiveelement-binding (DREB) protein / C-repeat binding factors (CBFs) belong to APETALA2 (AP2) family transcription factors that bind to DRE/CRT cis-element and regulate the expression of stress-responsive genes. DREB1/CBF genes, therefore, play an important role in increasing stress tolerance in plants and their deployment using transgenic technology seems to be a potential alternative in management of abiotic stresses in crop plants. This review is mainly focussed on the structural characteristics as well as transcriptional regulation of gene expression in response to various abiotic stresses, with particular emphasis on the role of DREB1/CBF regulon in stress-responsive gene expression. The recent progress related to genetic engineering of DREB1/CBF transcription factors in various crops and model plants is also summarized.

  6. Recent Advances in Utilizing Transcription Factors to Improve Plant Abiotic Stress Tolerance by Transgenic Technology

    PubMed Central

    Wang, Hongyan; Wang, Honglei; Shao, Hongbo; Tang, Xiaoli

    2016-01-01

    Agricultural production and quality are adversely affected by various abiotic stresses worldwide and this will be exacerbated by the deterioration of global climate. To feed a growing world population, it is very urgent to breed stress-tolerant crops with higher yields and improved qualities against multiple environmental stresses. Since conventional breeding approaches had marginal success due to the complexity of stress tolerance traits, the transgenic approach is now being popularly used to breed stress-tolerant crops. So identifying and characterizing the critical genes involved in plant stress responses is an essential prerequisite for engineering stress-tolerant crops. Far beyond the manipulation of single functional gene, engineering certain regulatory genes has emerged as an effective strategy now for controlling the expression of many stress-responsive genes. Transcription factors (TFs) are good candidates for genetic engineering to breed stress-tolerant crop because of their role as master regulators of many stress-responsive genes. Many TFs belonging to families AP2/EREBP, MYB, WRKY, NAC, bZIP have been found to be involved in various abiotic stresses and some TF genes have also been engineered to improve stress tolerance in model and crop plants. In this review, we take five large families of TFs as examples and review the recent progress of TFs involved in plant abiotic stress responses and their potential utilization to improve multiple stress tolerance of crops in the field conditions. PMID:26904044

  7. Spatially dependent biotic and abiotic factors drive survivorship and physical structure of green roof vegetation.

    PubMed

    Aloisio, Jason M; Palmer, Matthew I; Giampieri, Mario A; Tuininga, Amy R; Lewis, James D

    2017-01-01

    Plant survivorship depends on biotic and abiotic factors that vary at local and regional scales. This survivorship, in turn, has cascading effects on community composition and the physical structure of vegetation. Survivorship of native plant species is variable among populations planted in environmentally stressful habitats like urban roofs, but the degree to which factors at different spatial scales affect survivorship in urban systems is not well understood. We evaluated the effects of biotic and abiotic factors on survivorship, composition, and physical structure of two native perennial species assemblages, one characterized by a mixture of C4 grasses and forbs (Hempstead Plains, HP) and one characterized by a mixture of C3 grasses and forbs (Rocky Summit, RS), that were initially sown at equal ratios of growth forms (5:1:4; grass, N-fixing forb and non-N-fixing forb) in replicate 2-m(2) plots planted on 10 roofs in New York City (New York, USA). Of 24 000 installed plants, 40% survived 23 months after planting. Within-roof factors explained 71% of variation in survivorship, with biotic (species identity and assemblage) factors accounting for 54% of the overall variation, and abiotic (growing medium depth and plot location) factors explaining 17% of the variation. Among-roof factors explained 29% of variation in survivorship and increased solar radiation correlated with decreased survivorship. While growing medium properties (pH, nutrients, metals) differed among roofs there was no correlation with survivorship. Percent cover and sward height increased with increasing survivorship. At low survivorship, cover of the HP assemblage was greater compared to the RS assemblage. Sward height of the HP assemblage was about two times greater compared to the RS assemblage. These results highlight the effects of local biotic and regional abiotic drivers on community composition and physical structure of green roof vegetation. As a result, initial green roof plant

  8. Roles of NAC transcription factors in the regulation of biotic and abiotic stress responses in plants

    PubMed Central

    Nuruzzaman, Mohammed; Sharoni, Akhter M.; Kikuchi, Shoshi

    2013-01-01

    NAC transcription factors are one of the largest families of transcriptional regulators in plants, and members of the NAC gene family have been suggested to play important roles in the regulation of the transcriptional reprogramming associated with plant stress responses. A phylogenetic analysis of NAC genes, with a focus on rice and Arabidopsis, was performed. Herein, we present an overview of the regulation of the stress responsive NAC SNAC/(IX) group of genes that are implicated in the resistance to different stresses. SNAC factors have important roles for the control of biotic and abiotic stresses tolerance and that their overexpression can improve stress tolerance via biotechnological approaches. We also review the recent progress in elucidating the roles of NAC transcription factors in plant biotic and abiotic stresses. Modification of the expression pattern of transcription factor genes and/or changes in their activity contribute to the elaboration of various signaling pathways and regulatory networks. However, a single NAC gene often responds to several stress factors, and their protein products may participate in the regulation of several seemingly disparate processes as negative or positive regulators. Additionally, the NAC proteins function via auto-regulation or cross-regulation is extensively found among NAC genes. These observations assist in the understanding of the complex mechanisms of signaling and transcriptional reprogramming controlled by NAC proteins. PMID:24058359

  9. Connecting RNA Processing to Abiotic Environmental Response in Arabidopsis: the role of a polyadenylation factor

    NASA Astrophysics Data System (ADS)

    Li, Q. Q.; Xu, R.; Hunt, A. G.; Falcone, D. L.

    Plants are constantly challenged by numerous environmental stresses both biotic and abiotic It is clear that plants have evolved to counter these stresses using all but limited means We recently discovered the potential role of a messenger RNA processing factor namely the Arabidopsis cleavage and polyadenylation specificity factor 30 kDa subunit AtCPSF30 when a mutant deficient in this factor displayed altered responses to an array of abiotic stresses This AtCPSF30 mutant named oxt6 exhibited an elevated tolerance to oxidative stress Microarray experiments of oxt6 and its complemented lines revealed an altered gene expression profile among which were antioxidative defense genes Interestingly the same gene encoding AtCPSF30 can also be transcribed into a large transcript that codes for a potential splicing factor Both protein products have a domain for RNA binding and a calmodulin binding domain activities of which have been confirmed by biochemical assays Surprisingly binding of AtCPSF30 to calmodulin inhibits the RNA-binding activity of the protein Mutational analysis shows that a small part of the protein is responsible for calmodulin binding and point mutations in this region abolished both RNA binding activity and the inhibition of this activity by calmodulin Analyses of the potential splicing factor are on going and the results will be presented The interesting possibilities for both the interplay between splicing and polyadenylation and the regulation of these processes by stimuli that act through

  10. Multiple NUCLEAR FACTOR Y Transcription Factors Respond to Abiotic Stress in Brassica napus L

    PubMed Central

    Xu, Li; Lin, Zhongyuan; Tao, Qing; Liang, Mingxiang; Zhao, Gengmao; Yin, Xiangzhen; Fu, Ruixin

    2014-01-01

    Members of the plant NUCLEAR FACTOR Y (NF-Y) family are composed of the NF-YA, NF-YB, and NF-YC subunits. In Brassica napus (canola), each of these subunits forms a multimember subfamily. Plant NF-Ys were reported to be involved in several abiotic stresses. In this study, we demonstrated that multiple members of thirty three BnNF-Ys responded rapidly to salinity, drought, or ABA treatments. Transcripts of five BnNF-YAs, seven BnNF-YBs, and two BnNF-YCs were up-regulated by salinity stress, whereas the expression of thirteen BnNF-YAs, ten BnNF-YBs, and four BnNF-YCs were induced by drought stress. Under NaCl treatments, the expression of one BnNF-YA10 and four NF-YBs (BnNF-YB3, BnNF-YB7, BnNF-YB10, and BnNF-YB14) were greatly increased. Under PEG treatments, the expression levels of four NF-YAs (BnNF-YA9, BnNF-YA10, BnNF-YA11, and BnNF-YA12) and five NF-YBs (BnNF-YB1, BnNF-YB8, BnNF-YB10, BnNF-YB13, and BnNF-YB14) were greatly induced. The expression profiles of 20 of the 27 salinity- or drought-induced BnNF-Ys were also affected by ABA treatment. The expression levels of six NF-YAs (BnNF-YA1, BnNF-YA7, BnNF-YA8, BnNF-YA9, BnNF-YA10, and BnNF-YA12) and seven BnNF-YB members (BnNF-YB2, BnNF-YB3, BnNF-YB7, BnNF-YB10, BnNF-YB11, BnNF-YB13, and BnNF-YB14) and two NF-YC members (BnNF-YC2 and BnNF-YC3) were greatly up-regulated by ABA treatments. Only a few BnNF-Ys were inhibited by the above three treatments. Several NF-Y subfamily members exhibited collinear expression patterns. The promoters of all stress-responsive BnNF-Ys harbored at least two types of stress-related cis-elements, such as ABRE, DRE, MYB, or MYC. The cis-element organization of BnNF-Ys was similar to that of Arabidopsis thaliana, and the promoter regions exhibited higher levels of nucleotide sequence identity with Brassica rapa than with Brassica oleracea. This work represents an entry point for investigating the roles of canola NF-Y proteins during abiotic stress responses and provides insight into

  11. Multiple NUCLEAR FACTOR Y transcription factors respond to abiotic stress in Brassica napus L.

    PubMed

    Xu, Li; Lin, Zhongyuan; Tao, Qing; Liang, Mingxiang; Zhao, Gengmao; Yin, Xiangzhen; Fu, Ruixin

    2014-01-01

    Members of the plant NUCLEAR FACTOR Y (NF-Y) family are composed of the NF-YA, NF-YB, and NF-YC subunits. In Brassica napus (canola), each of these subunits forms a multimember subfamily. Plant NF-Ys were reported to be involved in several abiotic stresses. In this study, we demonstrated that multiple members of thirty three BnNF-Ys responded rapidly to salinity, drought, or ABA treatments. Transcripts of five BnNF-YAs, seven BnNF-YBs, and two BnNF-YCs were up-regulated by salinity stress, whereas the expression of thirteen BnNF-YAs, ten BnNF-YBs, and four BnNF-YCs were induced by drought stress. Under NaCl treatments, the expression of one BnNF-YA10 and four NF-YBs (BnNF-YB3, BnNF-YB7, BnNF-YB10, and BnNF-YB14) were greatly increased. Under PEG treatments, the expression levels of four NF-YAs (BnNF-YA9, BnNF-YA10, BnNF-YA11, and BnNF-YA12) and five NF-YBs (BnNF-YB1, BnNF-YB8, BnNF-YB10, BnNF-YB13, and BnNF-YB14) were greatly induced. The expression profiles of 20 of the 27 salinity- or drought-induced BnNF-Ys were also affected by ABA treatment. The expression levels of six NF-YAs (BnNF-YA1, BnNF-YA7, BnNF-YA8, BnNF-YA9, BnNF-YA10, and BnNF-YA12) and seven BnNF-YB members (BnNF-YB2, BnNF-YB3, BnNF-YB7, BnNF-YB10, BnNF-YB11, BnNF-YB13, and BnNF-YB14) and two NF-YC members (BnNF-YC2 and BnNF-YC3) were greatly up-regulated by ABA treatments. Only a few BnNF-Ys were inhibited by the above three treatments. Several NF-Y subfamily members exhibited collinear expression patterns. The promoters of all stress-responsive BnNF-Ys harbored at least two types of stress-related cis-elements, such as ABRE, DRE, MYB, or MYC. The cis-element organization of BnNF-Ys was similar to that of Arabidopsis thaliana, and the promoter regions exhibited higher levels of nucleotide sequence identity with Brassica rapa than with Brassica oleracea. This work represents an entry point for investigating the roles of canola NF-Y proteins during abiotic stress responses and provides insight into

  12. Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

    SciTech Connect

    Meike, A.; Stroes-Gascoyne, S.

    2000-08-01

    A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behavior into performance assessment models. One effort was to expand an existing modeling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated as well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories: (1) abiotic factors, (2) community dynamics and in-situ considerations, (3) nutrient considerations and (4) transport of radionuclides. The complete bibliography represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain.

  13. Abscisic-acid-dependent basic leucine zipper (bZIP) transcription factors in plant abiotic stress.

    PubMed

    Banerjee, Aditya; Roychoudhury, Aryadeep

    2017-01-01

    One of the major causes of significant crop loss throughout the world is the myriad of environmental stresses including drought, salinity, cold, heavy metal toxicity, and ultraviolet-B (UV-B) rays. Plants as sessile organisms have evolved various effective mechanism which enable them to withstand this plethora of stresses. Most of such regulatory mechanisms usually follow the abscisic-acid (ABA)-dependent pathway. In this review, we have primarily focussed on the basic leucine zipper (bZIP) transcription factors (TFs) activated by the ABA-mediated signalosome. Upon perception of ABA by specialized receptors, the signal is transduced via various groups of Ser/Thr kinases, which phosphorylate the bZIP TFs. Following such post-translational modification of TFs, they are activated so that they bind to specific cis-acting sequences called abscisic-acid-responsive elements (ABREs) or GC-rich coupling elements (CE), thereby influencing the expression of their target downstream genes. Several in silico techniques have been adopted so far to predict the structural features, recognize the regulatory modification sites, undergo phylogenetic analyses, and facilitate genome-wide survey of TF under multiple stresses. Current investigations on the epigenetic regulation that controls greater accessibility of the inducible regions of DNA of the target gene to the bZIP TFs exclusively under stress situations, along with the evolved stress memory responses via genomic imprinting mechanism, have been highlighted. The potentiality of overexpression of bZIP TFs, either in a homologous or in a heterologous background, in generating transgenic plants tolerant to various abiotic stressors have also been addressed by various groups. The present review will provide a coherent documentation on the functional characterization and regulation of bZIP TFs under multiple environmental stresses, with the major goal of generating multiple-stress-tolerant plant cultivars in near future.

  14. The Red Queen and the Court Jester: species diversity and the role of biotic and abiotic factors through time.

    PubMed

    Benton, Michael J

    2009-02-06

    Evolution may be dominated by biotic factors, as in the Red Queen model, or abiotic factors, as in the Court Jester model, or a mixture of both. The two models appear to operate predominantly over different geographic and temporal scales: Competition, predation, and other biotic factors shape ecosystems locally and over short time spans, but extrinsic factors such as climate and oceanographic and tectonic events shape larger-scale patterns regionally and globally, and through thousands and millions of years. Paleobiological studies suggest that species diversity is driven largely by abiotic factors such as climate, landscape, or food supply, and comparative phylogenetic approaches offer new insights into clade dynamics.

  15. A membrane-bound NAC transcription factor as an integrator of biotic and abiotic stress signals.

    PubMed

    Seo, Pil Joon; Park, Chung-Mo

    2010-05-01

    Transcription factors are central components of gene regulatory networks that mediate virtually all aspects of growth and developmental processes in biological systems. The activity of transcription factors is regulated at multiple steps, such as gene transcription, posttranscriptional RNA processing, posttranslational modification, protein-protein interactions, and controlled protein turnover. Controlled activation of dormant, membrane-bound transcription factor (MTF) is an intriguing regulatory mechanism that ensures quick transcriptional responses to environmental fluctuations in plants, in which various stress hormones serve as signaling mediators. NTL6 is proteolytically activated upon exposure to cold and induces expression of the Pathogenesis-Related (PR) genes. The membrane-mediated cold signaling in inducing pathogen resistance is considered to be an adaptive strategy that protects plants against infection by hydrophilic pathogens frequently occurring during cold season. We found that NTL6 also mediates abscisic acid (ABA) regulation of abiotic stress responses in Arabidopsis. NTL6 is proteolytically activated by ABA. Transgenic plants overexpressing a nuclear NTL6 form (35S:6ΔC) exhibited a hypersensitive response to ABA and high salinity in seed germination. Taken together, these observations indicate that NTL6 plays an integrative role in plant responses to both biotic and abiotic stress conditions.

  16. Environmental Selenium Transformations: Distinguishing Abiotic and Biotic Factors Influencing Se Redox Transformations

    NASA Astrophysics Data System (ADS)

    Rosenfeld, C.; Kenyon, J.; James, B. R.; Santelli, C. M.

    2014-12-01

    Worldwide, selenium (Se) is proving to be a significant environmental concern, with many anthropogenic activities (e.g. coal mining and combustion, phosphate mining and agricultural irrigation) releasing potentially hazardous concentrations into surface and subsurface ecosystems. The US EPA is currently considering aquatic Se regulations, however no guidelines exist for excess soil Se, despite its ability to act as a persistent Se source. Various abiotic and biological processes mediate Se oxidation/reduction (redox) transformations in soils, thus influencing its solubility and bioavailability. In this research we assess (1) the ability of metal-transforming fungal species to aerobically reduce Se (Se (IV and/or VI) to Se(0)), and (2) the relative contribution of biotic and abiotic pathways for aerobic Se transformation. The primary objective of this research is to determine what abiotic and biotic factors enhance or restrict Se bioavailability. Results indicate that fungal-mediated Se reduction may be quite widespread, with at least 7 out of 10 species of known Mn(II)-oxidizing fungi isolated from metal impacted environments also identified as capable of aerobically reducing Se(IV) and/or Se(VI) to Se(0). Increasing concentrations of selenite (SeO32-; Se(IV)) and selenate (SeO42-; Se(VI)) generally reduced fungal growth rates, although selenate was more likely to inhibit fungal growth than selenite. To study oxidation, Se(0) was combined with Mn(III/IV) (hydr)oxides (henceforth referred to as Mn oxides), Se-transforming fungi (Alternaria alternata), and oxalic acid to mimic Se biogeochemistry at the plant-soil interface. Increased pH in the presence of fungi (7.2 with fungi, 6.8 without fungi after 24 days) was observed. Additionally, a slight decrease in redox potential was measured for incubations without Mn oxides (236 mV with Mn oxides, 205 mV without Mn oxides after 24 days), indicating that Mn oxides may enhance Se oxidation. Elemental Se oxidation rates to

  17. Effect of abiotic factors on seasonal population dynamics of Lutzomyia longipalpis (Diptera: Psychodidae) in northeastern Brazil.

    PubMed

    Ximenes, Maria de Fátima Freire de Melo; Castellón, Eloy G; De Souza, Maria de Fátima; Menezes, Alexandre A Lara; Queiroz, José Wilton; Macedo e Silva, Virgínia Penéllope; Jerônimo, Selma M B

    2006-09-01

    The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz and Neiva) (Diptera: Psychodidae), the vector of Leishmania infantum, the causative agent of visceral leishmaniasis in Brazil. Sand flies were captured in peridomestic habitats biweekly for 3 yr. Cross-correlation tests and spectral analysis were used to analyze the simultaneous and lag-time correlations between Lu. longipalpis population densities and abiotic factors of temperature, relative humidity, wind velocity, and rainfall. Distinct seasonal patterns were observed for males and females, with intervals of 6 mo between population peaks for males and 12 mo for females. Peak female population densities lagged 3 mo behind the maximum annual temperature. Female population density was negatively correlated with relative humidity. An increase in average wind velocity was followed by a decrease in the number of females for 2 wk. Understanding the relationship between the seasonal population dynamics of Lu. longipalpis and abiotic factors will contribute to the design of better control measures to decrease transmission of L. infantum and consequently the incidence of leishmaniasis.

  18. The Miscanthus NAC transcription factor MlNAC9 enhances abiotic stress tolerance in transgenic Arabidopsis.

    PubMed

    Zhao, Xun; Yang, Xuanwen; Pei, Shengqiang; He, Guo; Wang, Xiaoyu; Tang, Qi; Jia, Chunlin; Lu, Ying; Hu, Ruibo; Zhou, Gongke

    2016-07-15

    NAC (NAM, ATAF1/2, and CUC2) transcription factors are known to play important roles in responses to abiotic stresses in plants. Currently, little information regarding the functional roles of NAC genes in stress tolerance is available in Miscanthus lutarioriparius, a promising bioenergy plant for cellulosic ethanol production. In this study, we carried out the functional characterization of MlNAC9 in abiotic stresses. MlNAC9 was shown to act as a nuclear localized transcription activator with the activation domain in its C-terminus. The overexpression of MlNAC9 in Arabidopsis conferred hypersensitivity to abscisic acid (ABA) at seed germination and root elongation stages. In addition, the overexpression of MlNAC9 led to increased seed germination rate and root growth under salt (NaCl) treatment. Meanwhile, the transgenic Arabidopsis overexpressing MlNAC9 showed enhanced tolerance to drought and cold stresses. The expression of stress-responsive marker genes was significantly increased in MlNAC9 overexpression lines compared to that of WT under ABA, drought, salt, and cold stresses. Correspondingly, the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly increased and the malondialdehyde (MDA) content was lower accumulated in MlNAC9 overexpression lines under drought and salt treatments. These results indicated that the overexpression of MlNAC9 improved the tolerance to abiotic stresses via an ABA-dependent pathway, and the enhanced tolerance of transgenic plants was mainly attributed to the increased expression of stress-responsive genes and the enhanced scavenging capability of reactive oxygen species (ROS).

  19. The WRKY transcription factors in the diploid woodland strawberry Fragaria vesca: Identification and expression analysis under biotic and abiotic stresses.

    PubMed

    Wei, Wei; Hu, Yang; Han, Yong-Tao; Zhang, Kai; Zhao, Feng-Li; Feng, Jia-Yue

    2016-08-01

    WRKY proteins comprise a large family of transcription factors that play important roles in response to biotic and abiotic stresses and in plant growth and development. To date, little is known about the WRKY gene family in strawberry. In this study, we identified 62 WRKY genes (FvWRKYs) in the wild diploid woodland strawberry (Fragaria vesca, 2n = 2x = 14) accession Heilongjiang-3. According to the phylogenetic analysis and structural features, these identified strawberry FvWRKY genes were classified into three main groups. In addition, eight FvWRKY-GFP fusion proteins showed distinct subcellular localizations in Arabidopsis mesophyll protoplasts. Furthermore, we examined the expression of the 62 FvWRKY genes in 'Heilongjiang-3' under various conditions, including biotic stress (Podosphaera aphanis), abiotic stresses (drought, salt, cold, and heat), and hormone treatments (abscisic acid, ethephon, methyl jasmonate, and salicylic acid). The expression levels of 33 FvWRKY genes were upregulated, while 12 FvWRKY genes were downregulated during powdery mildew infection. FvWRKY genes responded to drought and salt treatment to a greater extent than to temperature stress. Expression profiles derived from quantitative real-time PCR suggested that 11 FvWRKY genes responded dramatically to various stimuli at the transcriptional level, indicating versatile roles in responses to biotic and abiotic stresses. Interaction networks revealed that the crucial pathways controlled by WRKY proteins may be involved in the differential response to biotic stress. Taken together, the present work may provide the basis for future studies of the genetic modification of WRKY genes for pathogen resistance and stress tolerance in strawberry.

  20. The Effects of Abiotic Factors on Induced Volatile Emissions in Corn Plants1

    PubMed Central

    Gouinguené, Sandrine P.; Turlings, Ted C.J.

    2002-01-01

    Many plants respond to herbivory by releasing a specific blend of volatiles that is attractive to natural enemies of the herbivores. In corn (Zea mays), this induced odor blend is mainly composed of terpenoids and indole. The induced signal varies with plant species and genotype, but little is known about the variation due to abiotic factors. Here, we tested the effect of soil humidity, air humidity, temperature, light, and fertilization rate on the emission of induced volatiles in young corn plants. Each factor was tested separately under constant conditions for the other factors. Plants released more when standing in dry soil than in wet soil, whereas for air humidity, the optimal release was found at around 60% relative humidity. Temperatures between 22°C and 27°C led to a higher emission than lower or higher temperatures. Light intensity had a dramatic effect. The emission of volatiles did not occur in the dark and increased steadily with an increase in the light intensity. An experiment with an unnatural light-dark cycle showed that the release was fully photophase dependent. Fertilization also had a strong positive effect; the emission of volatiles was minimal when plants were grown under low nutrition, even when results were corrected for plant biomass. Changes in all abiotic factors caused small but significant changes in the relative ratios among the different compounds (quality) in the induced odor blends, except for air humidity. Hence, climatic conditions and nutrient availability can be important factors in determining the intensity and variability in the release of induced plant volatiles. PMID:12114583

  1. Identification of important abiotic and biotic factors in the biodegradation of poly(l-lactic acid).

    PubMed

    Husárová, Lucie; Pekařová, Silvie; Stloukal, Petr; Kucharzcyk, Pavel; Verney, Vincent; Commereuc, Sophie; Ramone, Audrey; Koutny, Marek

    2014-11-01

    The biodegradation of four poly(l-lactic acid) (PLA) samples with molecular weights (MW) ranging from approximately 34 to 160kgmol(-1) was investigated under composting conditions. The biodegradation rate decreased, and initial retardation was discernible in parallel with the increasing MW of the polymer. Furthermore, the specific surface area of the polymer sample was identified as the important factor accelerating biodegradation. Microbial community compositions and dynamics during the biodegradation of different PLA were monitored by temperature gradient gel electrophoresis, and were found to be virtually identical for all PLA materials and independent of MW. A specific PLA degrading bacteria was isolated and tentatively designated Thermopolyspora flexuosa FTPLA. The addition of a limited amount of low MW PLA did not accelerate the biodegradation of high MW PLA, suggesting that the process is not limited to the number of specific degraders and/or the induction of specific enzymes. In parallel, abiotic hydrolysis was investigated for the same set of samples and their courses found to be quasi-identical with the biodegradation of all four PLA samples investigated. This suggests that the abiotic hydrolysis represented a rate limiting step in the biodegradation process and the organisms present were not able to accelerate depolymerization significantly by the action of their enzymes.

  2. Geographic variation of floral traits in Nicotiana glauca : Relationships with biotic and abiotic factors

    NASA Astrophysics Data System (ADS)

    Nattero, Julieta; Sérsic, Alicia N.; Cocucci, Andrea A.

    2011-09-01

    Geographic pattern of phenotypic variation can appear in a clinal or a mosaic fashion and can evidence adaptive or non-adaptive variation. To shed light on the mechanisms underlying this variation, we studied the relationships between geographic variation of floral traits and both biotic and abiotic factors of the hummingbird-pollinated plant, Nicotiana glauca, across its natural range. We obtained floral measures of 38 populations from an area about 1600 km long and 1050 km wide and an altitude range from 7 to over 3400 m. We used a MANOVA to detect between-population differentiations in flower traits and a DFA to determine the traits that best discriminate between populations. To test for associations between floral traits and climatic variables we used correlation analysis. We explored any possible distance-based pattern of variation (either geographic or altitudinal) in floral traits or bill length of pollinators using Mantel tests. Finally, we used a multiple regression to analyze simultaneously the effects and relative importance of abiotic predictor variables and bill length on corolla length. We found a high variation in flower traits among populations. Morphometric traits were the ones that best discriminated across populations. There was a clinal pattern of floral phenotypic variation explained by climatic factors. Differences in floral phenotypic distances were structured by altitudinal distances but not by geographic distances. Bill length of the hummingbird pollinators was structured both by altitudinal and geographic distances. Differences in bill length of hummingbird pollinators explained differences in corolla length across populations. Our findings support the assumption of flower evolution at a broad geographic scale. Floral traits seem to be structured not only by altitude but also by climatic factors.

  3. Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4

    PubMed Central

    Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

    2017-01-01

    Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R2 = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2. PMID:28252030

  4. Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4

    NASA Astrophysics Data System (ADS)

    Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

    2017-03-01

    Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R2 = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2.

  5. The role of abiotic factors in the Cambrian Substrate Revolution: A review from the benthic community replacements of West Gondwana

    NASA Astrophysics Data System (ADS)

    Álvaro, J. Javier; Zamora, Samuel; Clausen, Sébastien; Vizcaïno, Daniel; Smith, Andrew B.

    2013-03-01

    The Cambrian Substrate Revolution refers to a substantial and "rapid" change to the nature of marine sedimentary substrates in the early Cambrian and is widely interpreted as a biologically-driven event, a direct response to evolutionary innovations in metazoan burrowing and the development of new shelly faunas. However, abiotic factors such as tectonic and climatic evolution also had the potential to restructure Cambrian substrates, and are here shown to be more plausible drivers of change in the benthic faunas of western Gondwana. The western Mediterranean region underwent a southward drift during Cambrian times, which drove a switch from subtropical carbonates to temperate siliciclastic substrates with short-term episodes of temperate carbonate productivity. As a result, microbial and shelly carbonates disappeared diachronously in a stepwise manner across the lower-middle Cambrian boundary interval. Archaeocyathan-microbial reefs were replaced by chancelloriid-eocrinoid-(spiculate) sponge meadows, in which the stepwise immigration of new echinoderm taxa was primarily controlled by extensional tectonic events, first recorded in rifting settings and later in passive-margin platforms. Availability of new kinds of substrate was thus the primary factor that controlled where and when evolutionary innovations in benthic strategies arose. Examples of this include the early Cambrian colonization of phosphatic hardgrounds and thrombolite crusts by chancelloriids, archaeocyathan and spiculate sponges, and the exploitation by benthos to the increasingly widespread availability of shelly grounds and carbonate firmgrounds by early-diagenetic cementation. A microbial mat/epifaunal antagonistic relationship is demonstrated for echinoderm pelmatozoans based on the non-overlapping palaeogeographic distributions of microbial reefs and mats versus mud-sticker pelmatozoans. Cambrian benthic communities thus evolved in parallel with substrates in response to abiotic factors rather

  6. ANALYSIS OF BIOTIC AND ABIOTIC FACTORS INFLUENCING THE OCCURRENCE OF WEST NILE VIRUS INFECTION IN TUNISIA.

    PubMed

    Ben Hassine, Th; Calistri, P; Ippoliti, C; Conte, A; Danzetta, M L; Bruno, R; Lelli, R; Bejaoui, M; Hammami, S

    2014-01-01

    Eco-climatic conditions are often associated with the occurrence of West Nile Disease (WND) cases. Among the complex set of biotic and abiotic factors influencing the emergence and spread of this vector-borne disease, two main variables have been considered to have a great influence on the probability of West Nile Virus (WNV) introduction and circulation in Tunisia: the presence of susceptible bird populations and the existence of geographical areas where the environmental and climatic conditions are more favourable to mosquito multiplications. The aim of this study was to identify and classify the climatic and environmental variables possibly associated with the occurrence of WNVhuman cases in Tunisia. The following environmental and climatic variables have been considered: wetlands and humid areas, Normalised Difference Vegetation Index (NDVI), temperatures and elevation. A preliminary analysis for the characterization of main variables associated with areas with a history of WNV human cases in Tunisia between 1997 and 2011 has been made. This preliminary analysis clearly indicates the closeness to marshes ecosystem, where migratory bird populations are located, as an important risk factor for WNV infection. On the contrary the temperature absolute seems to be not a significant factor in Tunisian epidemiological situation. In relation to NDVI values, more complex considerations should be made.

  7. De novo transcriptome sequence assembly and identification of AP2/ERF transcription factor related to abiotic stress in parsley (Petroselinum crispum).

    PubMed

    Li, Meng-Yao; Tan, Hua-Wei; Wang, Feng; Jiang, Qian; Xu, Zhi-Sheng; Tian, Chang; Xiong, Ai-Sheng

    2014-01-01

    Parsley is an important biennial Apiaceae species that is widely cultivated as herb, spice, and vegetable. Previous studies on parsley principally focused on its physiological and biochemical properties, including phenolic compound and volatile oil contents. However, little is known about the molecular and genetic properties of parsley. In this study, 23,686,707 high-quality reads were obtained and assembled into 81,852 transcripts and 50,161 unigenes for the first time. Functional annotation showed that 30,516 unigenes had sequence similarity to known genes. In addition, 3,244 putative simple sequence repeats were detected in curly parsley. Finally, 1,569 of the identified unigenes belonged to 58 transcription factor families. Various abiotic stresses have a strong detrimental effect on the yield and quality of parsley. AP2/ERF transcription factors have important functions in plant development, hormonal regulation, and abiotic response. A total of 88 putative AP2/ERF factors were identified from the transcriptome sequence of parsley. Seven AP2/ERF transcription factors were selected in this study to analyze the expression profiles of parsley under different abiotic stresses. Our data provide a potentially valuable resource that can be used for intensive parsley research.

  8. Effects of abiotic factors and species interactions on estimates of male plant function: a meta-analysis.

    PubMed

    Schaeffer, Robert N; Manson, Jessamyn S; Irwin, Rebecca E

    2013-03-01

    The majority of angiosperms are hermaphroditic with total fitness comprised of both male and female components of reproduction. However, most studies examining the effects of abiotic factors and species interactions on fitness have focussed on female reproduction, potentially biasing our understanding of the consequences of environmental factors on total fitness. Here, we use meta-analysis to test how environmental factors affect male function. We obtained 278 effect sizes from 96 studies that measured male function responses to manipulated environmental factors. We found significant effects of abiotic factors and species interactions on estimates of male function, with responses varying depending on environmental factor identity. Male and female responses were correlated for abiotic factor manipulations, but varied based on the type of species interaction (antagonistic or mutualistic). This suggests that measuring only female function may misrepresent whole-plant reproduction depending on context. Finally, we found differences amongst components of male function in response to environmental factors, suggesting that some male function estimates may fail to capture the effects of environmental factors on male fitness. Our results demonstrate the importance of incorporating male function into ecological and evolutionary studies to provide a more accurate understanding of the effects of environmental factors on total fitness.

  9. The relationships among biotic and abiotic factors as control soil degradation processes along a Mediterranean pluviometric gradient.

    NASA Astrophysics Data System (ADS)

    Damian Ruiz Sinoga, Jose; Romero Diaz, Asunción

    2010-05-01

    The shifts to soil properties that resulted from changes in water availability along a pluviometric gradient from humid to semiarid/arid Mediterranean climate were analyzed. The study was carried out at eight experimental sites in southern Spain and assessed the influence of a reduction in annual average rainfall along the pluviometric gradient on various physical, chemical and hydrological properties of the topsoil, and on the biotic characteristics of the environment. The aims were to assess the soil degradation status, and to determine if any of the soil variables studied could be used as soil degradation indicators. For each experimental site the relationships among a series of edaphic, hydrological and biological properties were investigated, and the principal factors affecting soil degradation were determined using principal component analysis. The properties included the clay, silt and sand content; organic matter; retained organic carbon; salinity; cation exchange capacity; structural stability; USLE K factor; bulk density; saturated hydraulic conductivity; soil moisture; the number of vegetal species; and vegetation cover. The results showed that relationships between biotic and abiotic factors controlled the soil degradation status along a pluviometric gradient from wet to semiarid/arid conditions in the Mediterranean area, and therefore the stability of the eco-geomorphological system depends on the dominant factor. A precipitation-based soil degradation threshold of approximately 500 mm/yr was established, as below this level the vegetation is no longer associated with the presence of greater soil moisture content, but adapts to degradation, as evidenced by the appearance of xerophytic species.

  10. The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish

    NASA Astrophysics Data System (ADS)

    Wenger, Amelia S.; Whinney, James; Taylor, Brett; Kroon, Frederieke

    2016-06-01

    Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change.

  11. Relative contribution of biotic and abiotic factors to the population density of the cassava green mite, Mononychellus tanajoa (Acari: Tetranychidae).

    PubMed

    Rêgo, Adriano S; Teodoro, Adenir V; Maciel, Anilde G S; Sarmento, Renato A

    2013-08-01

    The cassava green mite, Mononychellus tanajoa, is a key pest of cassava, Manihot esculenta Crantz (Euphorbiaceae), and it may be kept in check by naturally occurring predatory mites of the family Phytoseiidae. In addition to predatory mites, abiotic factors may also contribute to regulate pest mite populations in the field. Here, we evaluated the population densities of both M. tanajoa and the generalist predatory mite Euseius ho DeLeon (Acari: Phytoseiidae) over the cultivation cycle (11 months) of cassava in four study sites located around the city of Miranda do Norte, Maranhão, Brazil. The abiotic variables rainfall, temperature and relative humidity were also recorded throughout the cultivation cycle of cassava. We determined the relative importance of biotic (density of E. ho) and abiotic (rainfall, temperature and relative humidity) factors to the density of M. tanajoa. The density of M. tanajoa increased whereas the density of E. ho remained constant throughout time. A hierarchical partitioning analysis revealed that most of the variance for the density of M. tanajoa was explained by rainfall and relative humidity followed by E. ho density and temperature. We conclude that abiotic factors, especially rainfall, were the main mechanisms driving M. tanajoa densities.

  12. The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish

    PubMed Central

    Wenger, Amelia S.; Whinney, James; Taylor, Brett; Kroon, Frederieke

    2016-01-01

    Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change. PMID:27350589

  13. The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish.

    PubMed

    Wenger, Amelia S; Whinney, James; Taylor, Brett; Kroon, Frederieke

    2016-06-28

    Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change.

  14. Effects of Abiotic Factors on the Phylogenetic Diversity of Bacterial Communities in Acidic Thermal Springs▿

    PubMed Central

    Mathur, Jayanti; Bizzoco, Richard W.; Ellis, Dean G.; Lipson, David A.; Poole, Alexander W.; Levine, Richard; Kelley, Scott T.

    2007-01-01

    Acidic thermal springs offer ideal environments for studying processes underlying extremophile microbial diversity. We used a carefully designed comparative analysis of acidic thermal springs in Yellowstone National Park to determine how abiotic factors (chemistry and temperature) shape acidophile microbial communities. Small-subunit rRNA gene sequences were PCR amplified, cloned, and sequenced, by using evolutionarily conserved bacterium-specific primers, directly from environmental DNA extracted from Amphitheater Springs and Roaring Mountain sediment samples. Energy-dispersive X-ray spectroscopy, X-ray diffraction, and colorimetric assays were used to analyze sediment chemistry, while an optical emission spectrometer was used to evaluate water chemistry and electronic probes were used to measure the pH, temperature, and Eh of the spring waters. Phylogenetic-statistical analyses found exceptionally strong correlations between bacterial community composition and sediment mineral chemistry, followed by weaker but significant correlations with temperature gradients. For example, sulfur-rich sediment samples contained a high diversity of uncultured organisms related to Hydrogenobaculum spp., while iron-rich sediments were dominated by uncultured organisms related to a diverse array of gram-positive iron oxidizers. A detailed analysis of redox chemistry indicated that the available energy sources and electron acceptors were sufficient to support the metabolic potential of Hydrogenobaculum spp. and iron oxidizers, respectively. Principal-component analysis found that two factors explained 95% of the genetic diversity, with most of the variance attributable to mineral chemistry and a smaller fraction attributable to temperature. PMID:17220248

  15. Abiotic and biotic factors that influence the bioavailability of gold nanoparticles to aquatic macrophytes.

    PubMed

    Glenn, J Brad; Klaine, Stephen J

    2013-09-17

    This research identified and characterized factors that influenced nanomaterial bioavailability to three aquatic plants: Azolla caroliniana Willd, Egeria densa Planch., and Myriophyllum simulans Orch. Plants were exposed to 4-, 18-, and 30-nm gold nanoparticles. Uptake was influenced by nanoparticle size, the presence of roots on the plant, and dissolved organic carbon in the media. Statistical analysis of the data also revealed that particle uptake was influenced by a 4-way (plant species, plant roots, particle size, and dissolved organic carbon) interaction suggesting nanoparticle bioavailability was a complex result of multiple parameters. Size and species dependent absorption was observed that was dependent on the presence of roots and nanoparticle size. The presence of dissolved organic carbon was found to associate with 4- and 18-nm gold nanoparticles in suspension and form a nanoparticle/organic matter complex that resulted in (1) minimized particle aggregation and (2) a decrease of nanoparticle absorption by the aquatic plants. The same effect was not observed with the 30-nm nanoparticle treatment. These results indicate that multiple factors, both biotic and abiotic, must be taken into account when predicting bioavailability of nanomaterials to aquatic plants.

  16. Effects of two abiotic factors and their interaction on Soil Carbon Dioxide flux

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Armstrong, Alona; Gristina, Luciano; Quinton, John

    2010-05-01

    Soils release more carbon per annum than current global anthropogenic emissions (Luo and Zhou, 2006). Soils emit carbon dioxide through mineralization and decomposition of organic matter and respiration of roots and soil organism (Houghton 2007) Evaluation of the effects of abiotic factors on microbial activity is of major importance in the context of mitigation greenhouse gases emissions. One of the key greenhouse gases is carbon dioxide (CO2) and previous studies demonstrate that soil CO2 emission is significantly affected by temperature and soil water content. There are a limited number of studies that examine the impact of bulk density and soil surface characteristics as a result of exposure to rain on CO2 emission, however, none examine their relative importance. Therefore, this study investigated the effects of soil compaction and exposure of the soil surface to rainfall and their interaction on CO2 release. We conducted a factorial soil core experiment with three different bulk densities (1.1 g cm-3, 1.3 g cm-3, 1.5 g cm-3) and three difference exposures to rainfall (no rain, 30 minutes and 90 minutes of rainfall). Water was poured on to the cores not exposed to rain and those exposed for 30 minutes through a gauze to ensure all cores received the same volume of water. Immediately the rainfall treatments the soil cores were incubated and soil CO2 efflux and water content were measured 1, 2, 5, 6, 9, and 10 days after the start of the incubation. The results indicate soil CO2 emissions and rate changes significantly through time and with different bulk densities and rain exposures. The relationship between rain exposure and CO2 is positive: CO2 emission was 53% and 42% greater for the 90 min and 30 min rainfall exposure, respectively, compared to those not exposed to rain. Bulk density exhibited a negative relationship with CO2 emission: soil compacted to a bulk density of 1.1 g cm-3 emitted 32% more CO2 than soil compacted to 1.5 g cm-3. Furthermore we found

  17. Observations on the balance between abiotic and biotic factors in plant-morphodynamic feedbacks (Invited)

    NASA Astrophysics Data System (ADS)

    Manners, R.; Lightbody, A.; Wilcox, A. C.; Sklar, L. S.; Stella, J. C.; Kui, L.

    2013-12-01

    The strength and direction of feedbacks between riparian vegetation and fluvial processes depend on the balance between abiotic (i.e., sediment supply, transport capacity) and biotic factors (i.e., plant morphology, stem density). We present results from flume experiments that test the influence of these factors on plant-morphodynamic feedbacks. For equilibrium (balance between sediment transport and supply) and supply-limited (transport exceeds sediment supply) conditions, we evaluated the impact of plant morphology (shrubby versus characteristically single-stemmed woody seedlings), height (10 to 120 cm), and configuration (individual and patches) on bed topography, velocity fields, and sediment flux. We conducted the experiments in a 28-meter long, sand-bedded flume (60 cm wide and 71 cm deep) at the UC-Berkeley Richmond Field Station, into which plants harvested from field sites were transplanted in a manner that maintained the root structure. Under equilibrium conditions, all sizes of the individual shrubby plants induced scour around the base of the plant and increased deposition downstream. Individual single-stemmed plants, however, did not greatly alter the flow and sediment transport field (when compared to baseline conditions). When transport capacity exceeded the supply of sediment, the impact of all plants diminished, and bed scour would lead to plant dislodgement. More rapid dislodgement for the shrubby species occurred as a result of the increased drag on the plant. Our results illustrate that the morphology of shrubby plants, with multiple stems and greater near-bed frontal area (compared to the single-stem plant), not only increases the influence of the plant on the flow and sediment transport fields but also may, under certain sediment supply conditions, contribute to its own mortality via scour. The results from these experiments highlight the importance of both abiotic and biotic conditions, and the balance between them, in determining the

  18. Multifaceted role of cycling DOF factor 3 (CDF3) in the regulation of flowering time and abiotic stress responses in Arabidopsis.

    PubMed

    Corrales, Alba-Rocio; Carrillo, Laura; Lasierra, Pilar; Nebauer, Sergio G; Dominguez-Figueroa, Jose; Renau-Morata, Begoña; Pollmann, Stephan; Granell, Antonio; Molina, Rosa-Victoria; Vicente-Carbajosa, Jesús; Medina, Joaquín

    2017-05-01

    DNA-binding with one finger (DOF)-type transcription factors are involved in many fundamental processes in higher plants, from responses to light and phytohormones to flowering time and seed maturation, but their relation with abiotic stress tolerance is largely unknown. Here, we identify the roles of CDF3, an Arabidopsis DOF gene in abiotic stress responses and developmental processes like flowering time. CDF3 is highly induced by drought, extreme temperatures and abscisic acid treatment. The CDF3 T-DNA insertion mutant cdf3-1 is much more sensitive to drought and low temperature stress, whereas CDF3 overexpression enhances the tolerance of transgenic plants to drought, cold and osmotic stress and promotes late flowering. Transcriptome analysis revealed that CDF3 regulates a set of genes involved in cellular osmoprotection and oxidative stress, including the stress tolerance transcription factors CBFs, DREB2A and ZAT12, which involve both gigantea-dependent and independent pathways. Consistently, metabolite profiling disclosed that the total amount of some protective metabolites including γ-aminobutyric acid, proline, glutamine and sucrose were higher in CDF3-overexpressing plants. Taken together, these results indicate that CDF3 plays a multifaceted role acting on both flowering time and abiotic stress tolerance, in part by controlling the CBF/DREB2A-CRT/DRE and ZAT10/12 modules.

  19. Abiotic Factors Affecting Benthic Invertebrate Biomass and Community Structure in a Fourth-Order Rocky Mountain Watershed

    NASA Astrophysics Data System (ADS)

    Chanat, J. G.; Clements, W. H.; MacDonald, L. H.

    2005-05-01

    The potential ecological impact of excess streambed sediment resulting from forest management activities is a persistent concern for land managers. This study examined the relationship between streambed sediment, along with other site- and reach-scale abiotic factors, and benthic macroinvertebrate community structure in a 272 km2 basin in the Colorado Front Range. Physical habitat parameters and invertebrates were sampled in late summer at 68 sites located in sixteen stream reaches. Invertebrate data were used to formulate twenty indices of community structure. Multiple regression identified site-level substrate particle size as the most important predictor of six indices, including total density (R2 = 0.22), biomass (R2 = 0.17), and taxa richness (R2 = 0.32). All of the remaining fourteen indices were most strongly predicted by reach-level variables, including discharge (percent shredders, R2 = 0.24; Plecoptera density, R2 = 0.29), and elevation (percent collector-filterers, R2 = 0.28; Trichoptera density, R2 = 0.37). Although the sites represented a wide range of substrate composition and embeddedness, no physical variable associated with fine sediment appeared as a strong predictor of any of the twenty indices. Thus, sediment is not among the most important factors associated with site-to-site variability of benthic community structure in this relatively pristine watershed.

  20. The Effect of Abiotic Factors on Marine Animal Body Size Evolution

    NASA Astrophysics Data System (ADS)

    Wang, X. F.; Wong, W.; Heim, N.; Payne, J.

    2015-12-01

    While there is evidence of a general increase in body size over time, there has been no comprehensive attempt to determine the influence of abiotic factors on body size. Although an increase in maximum body size has been observed during and after the Precambrian oxidation events in the Late Archean and at the onset of the Cambrian, these observations took into account the appearance of eukaryotic life and multicellular life respectively. Using a database of marine animal body sizes spanning the Phanerozoic, we conducted a series of Pearson product-moment correlation tests with igneous rock weathering (Strontium-87: Strontium-86), rate of carbon cycle (δ13C), temperature (δ18O), CO2 concentration, sulfate mineral weathering (δ34S), atmospheric oxygen concentration, and sea level as independent variables, and mean body size as the dependent variable. Our test yielded a correlation coefficient of 0.81 between δ18O and body size, and -0.78 between rCO2 and body size; since δ18O is inversely correlated with temperature, these results indicate that both temperature and CO2 have strong inverse relationships with body size. Atmospheric oxygen yielded a correlation coefficient of 0.09, demonstrating that it ceased to play an influential role in shaping body sizes following the start of the Phanerozoic.

  1. Effect of abiotic factors on the unique glitter-like iridescence of Cellulophaga lytica.

    PubMed

    Kientz, Betty; Marié, Pauline; Rosenfeld, Eric

    2012-08-01

    Iridescence is a property of structural color that has been poorly documented in the prokaryotic kingdom. We recently isolated a Cellulophaga lytica strain that exhibits, on solid media, a unique intense glitter-like iridescence in reflection. Iridescence of C. lytica CECT 8139 was optically and physically characterized but physiological significance of the phenomenon was not. In the present work, we investigated the effect of key abiotic factors on C. lytica's growth and iridescence. Special attention was paid to conditions that mimic rocky shore ecosystem, the natural biotope of C. lytica. We found that C. lytica's iridescence required the presence of seawater. The phenomenon was not influenced by light exposure or plate orientation during growth. Cellulophaga lytica's iridescence occurred under a wide range of culture conditions notably under psychrophilic, halophilic, and hydric stress conditions. Changes in colonies' colors (blue, violet, red, yellow, and green) were linked to cell density. These data indicate that iridescence is induced under conditions that mimic the natural biotope of C. lytica.

  2. Impact of Abiotic Factors on Onion Thrips (Thysanoptera: Thripidae) Aerial Dispersal in an Onion Ecosystem.

    PubMed

    Smith, Erik A; Shields, E J; Nault, B A

    2016-10-01

    Onion thrips, Thrips tabaci Lindeman, is a significant pest of onion crops worldwide, but little is known about its patterns of aerial dispersal in the context of abiotic environmental factors. Thrips tabaci adults were passively collected from the air column above onion fields in western New York using clear sticky cards over a series of sampling periods in 2012, 2013, and 2014 while on-site weather conditions were recorded. Results indicated that T. tabaci adult densities on aerial traps during daylight averaged 279 times greater per hour than densities on similar traps at night. Adult dispersal also tended to spike during presunset, indicating that thrips initiated flight diurnally and within 1 h before sunset. Densities of T. tabaci on aerial traps increased significantly as temperature increased above 17 °C and 90% of the thrips were captured between 20.8 and 27.7 °C; no thrips were captured above 30.6 °C. Densities of T. tabaci on aerial traps decreased significantly as wind speed increased, with no thrips captured at winds exceeding 3.8 m/s (13.7 kph). In 2013 and 2014, T. tabaci densities on aerial traps prior to the passage of a cold front (relatively high atmospheric pressure and temperature with low wind speed) were significantly greater than densities after passage of the front, suggesting that T. tabaci disperses on synoptic weather systems.

  3. Soybean NAC transcription factors promote abiotic stress tolerance and lateral root formation in transgenic plants.

    PubMed

    Hao, Yu-Jun; Wei, Wei; Song, Qing-Xin; Chen, Hao-Wei; Zhang, Yu-Qin; Wang, Fang; Zou, Hong-Feng; Lei, Gang; Tian, Ai-Guo; Zhang, Wan-Ke; Ma, Biao; Zhang, Jin-Song; Chen, Shou-Yi

    2011-10-01

    NAC transcription factors play important roles in plant growth, development and stress responses. Previously, we identified multiple NAC genes in soybean (Glycine max). Here, we identify the roles of two genes, GmNAC11 and GmNAC20, in stress responses and other processes. The two genes were differentially induced by multiple abiotic stresses and plant hormones, and their transcripts were abundant in roots and cotyledons. Both genes encoded proteins that localized to the nucleus and bound to the core DNA sequence CGT[G/A]. In the protoplast assay system, GmNAC11 acts as a transcriptional activator, whereas GmNAC20 functions as a mild repressor; however, the C-terminal end of GmANC20 has transcriptional activation activity. Over-expression of GmNAC20 enhances salt and freezing tolerance in transgenic Arabidopsis plants; however, GmNAC11 over-expression only improves salt tolerance. Over-expression of GmNAC20 also promotes lateral root formation. GmNAC20 may regulate stress tolerance through activation of the DREB/CBF-COR pathway, and may control lateral root development by altering auxin signaling-related genes. GmNAC11 probably regulates DREB1A and other stress-related genes. The roles of the two GmNAC genes in stress tolerance were further analyzed in soybean transgenic hairy roots. These results provide a basis for genetic manipulation to improve the agronomic traits of important crops.

  4. Abiotic factors affecting summer distribution and movement of male paddlefish, Polyodon spathula, in a prairie reservoir

    USGS Publications Warehouse

    Paukert, C.P.; Fisher, W.L.

    2000-01-01

    Six male paddlefish, Polyodon spathula, were implanted with ultrasonic temperature-sensing transmitters and tracked during June through August 1997 to quantify effects of physicochemical conditions on their distribution and movement in Keystone Reservoir, Oklahoma. Paddlefish moved about twice as much during night than day. Movement rate of paddlefish was related to reservoir water level, inflow, and discharge from the reservoir at night; however, none of these variables was significant during the day. Location in the reservoir (distance from the dam) was negatively related to water level and positively related to inflow during day and night periods. Location in the reservoir was negatively related to discharge during the day. Paddlefish avoided the highest available water temperatures, but did not always avoid low dissolved oxygen concentrations. Paddlefish avoided the Cimarron River arm of the reservoir in summer, possibly because of high salinity. Our study demonstrates that distribution of paddlefish during summer and movement in Keystone Reservoir was influenced by physicochemical and hydrologic conditions in the system. However, biotic factors (e.g., food availability) not measured in this study may have been influenced by abiotic conditions in the reservoir.

  5. Abiotic factors and trap design modulate the performance of traps used to monitor the plum curculio.

    PubMed

    Lamothe, Steve; Chouinard, Gérald; Vincent, Charles

    2008-12-01

    All published studies on effects of abiotic factors on plum curculio, Conotrachelus nenuphar (Hersbt), adults have taken a retrospective approach. Here, we present the results of experiments where factors and their levels were determined and controlled a priori. We compared the effectiveness of miniature pyramidal traps (45 by 20 by 20 cm) constructed of four kind of materials--wood, geotextile, nylon screening, and corrugated plastic--to monitor overwintered and summer adults of univoltine plum curculio. We also studied the effects of photoperiod, temperature, wind, and rain on pyramidal trap effectiveness. The experiments, which were replicated over time, were done in two controlled chambers that were divided into four sections, corresponding to simulated combinations (wind or no wind/rain or no rain). The temperatures tested (15, 20, and 25 degrees C) were randomly assigned in the chambers. During scotophase, geotextile traps captured significantly more overwintered and summer adults than traps made of other materials. The maximum proportion of captures (for overwintered and summer adults) during photophase was obtained at 25 degrees C, and it was significantly different than captures at 15 and 20 degrees C. During scotophase, significantly more overwintered and summer plum curculios were caught at 20 and 25 degrees C than at 15 degrees C. Our experiments demonstrated that geotextile is a good alternative to wooden pyramidal trap. Our results suggest that captures were higher 1) at night, 2) during warmer periods (20 and 25 degrees C), 3) when wind velocity was low and 4) during or shortly after rainfall, and 5) that photoperiod is a factor having an important predictive value for plum curculio captures.

  6. Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors.

    PubMed

    Garchitorena, Andrés; Guégan, Jean-François; Léger, Lucas; Eyangoh, Sara; Marsollier, Laurent; Roche, Benjamin

    2015-07-28

    Host-parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors.

  7. Understanding Plant Community Responses to Combinations of Biotic and Abiotic Factors in Different Phases of the Plant Growth Cycle

    PubMed Central

    Wood, Kevin A.; Stillman, Richard A.; Clarke, Ralph T.; Daunt, Francis; O’Hare, Matthew T.

    2012-01-01

    Understanding plant community responses to combinations of biotic and abiotic factors is critical for predicting ecosystem response to environmental change. However, studies of plant community regulation have seldom considered how responses to such factors vary with the different phases of the plant growth cycle. To address this deficit we studied an aquatic plant community in an ecosystem subject to gradients in mute swan (Cygnus olor) herbivory, riparian shading, water temperature and distance downstream of the river source. We quantified abundance, species richness, evenness, flowering and dominance in relation to biotic and abiotic factors during the growth-, peak-, and recession-phases of the plant growth cycle. We show that the relative importance of biotic and abiotic factors varied between plant community properties and between different phases of the plant growth cycle. Herbivory became more important during the later phases of peak abundance and recession due to an influx of swans from adjacent pasture fields. Shading by riparian vegetation also had a greater depressing effect on biomass in later seasons, probably due to increased leaf abundance reducing light intensity reaching the aquatic plants. The effect of temperature on community diversity varied between upstream and downstream sites by altering the relative competitiveness of species at these sites. These results highlight the importance of seasonal patterns in the regulation of plant community structure and function by multiple factors. PMID:23166777

  8. Understanding plant community responses to combinations of biotic and abiotic factors in different phases of the plant growth cycle.

    PubMed

    Wood, Kevin A; Stillman, Richard A; Clarke, Ralph T; Daunt, Francis; O'Hare, Matthew T

    2012-01-01

    Understanding plant community responses to combinations of biotic and abiotic factors is critical for predicting ecosystem response to environmental change. However, studies of plant community regulation have seldom considered how responses to such factors vary with the different phases of the plant growth cycle. To address this deficit we studied an aquatic plant community in an ecosystem subject to gradients in mute swan (Cygnus olor) herbivory, riparian shading, water temperature and distance downstream of the river source. We quantified abundance, species richness, evenness, flowering and dominance in relation to biotic and abiotic factors during the growth-, peak-, and recession-phases of the plant growth cycle. We show that the relative importance of biotic and abiotic factors varied between plant community properties and between different phases of the plant growth cycle. Herbivory became more important during the later phases of peak abundance and recession due to an influx of swans from adjacent pasture fields. Shading by riparian vegetation also had a greater depressing effect on biomass in later seasons, probably due to increased leaf abundance reducing light intensity reaching the aquatic plants. The effect of temperature on community diversity varied between upstream and downstream sites by altering the relative competitiveness of species at these sites. These results highlight the importance of seasonal patterns in the regulation of plant community structure and function by multiple factors.

  9. Crepuscular Flight Activity of an Invasive Insect Governed by Interacting Abiotic Factors

    PubMed Central

    Chen, Yigen; Seybold, Steven J.

    2014-01-01

    Seasonal and diurnal flight patterns of the invasive walnut twig beetle, Pityophthorus juglandis, were assessed between 2011 and 2014 in northern California, USA in the context of the effects of ambient temperature, light intensity, wind speed, and barometric pressure. Pityophthorus juglandis generally initiated flight in late January and continued until late November. This seasonal flight could be divided approximately into three phases (emergence: January–March; primary flight: May–July; and secondary flight: September–October). The seasonal flight response to the male-produced aggregation pheromone was consistently female-biased (mean of 58.9% females). Diurnal flight followed a bimodal pattern with a minor peak in mid-morning and a major peak at dusk (76.4% caught between 1800 and 2200 h). The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed. A model selection procedure indicated that the four abiotic factors collectively and interactively governed P. juglandis diurnal flight. For both sexes, flight peaked under the following second-order interactions among the factors when: 1) temperature between was 25 and 30°C and light intensity was less than 2000 lux; 2) temperature was between 25 and 35°C and barometric pressure was between 752 and 762 mba (and declined otherwise); 3) barometric pressure was between 755 and 761 mba and light intensity was less than 2000 lux (and declined otherwise); and 4) temperature was ca. 30°C and wind speed was ca. 2 km/h. Thus, crepuscular flight activity of this insect can be best explained by the coincidence of moderately high temperature, low light intensity, moderate wind speed, and low to moderate barometric pressure. The new knowledge provides physical and temporal guidelines for the application of semiochemical-based control techniques as part of an IPM program for

  10. Abiotic factors affecting the persistence of avian influenza virus in surface waters of waterfowl habitats.

    PubMed

    Keeler, Shamus P; Dalton, Melinda S; Cressler, Alan M; Berghaus, Roy D; Stallknecht, David E

    2014-05-01

    Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-μm filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats.

  11. Crepuscular flight activity of an invasive insect governed by interacting abiotic factors.

    PubMed

    Chen, Yigen; Seybold, Steven J

    2014-01-01

    Seasonal and diurnal flight patterns of the invasive walnut twig beetle, Pityophthorus juglandis, were assessed between 2011 and 2014 in northern California, USA in the context of the effects of ambient temperature, light intensity, wind speed, and barometric pressure. Pityophthorus juglandis generally initiated flight in late January and continued until late November. This seasonal flight could be divided approximately into three phases (emergence: January-March; primary flight: May-July; and secondary flight: September-October). The seasonal flight response to the male-produced aggregation pheromone was consistently female-biased (mean of 58.9% females). Diurnal flight followed a bimodal pattern with a minor peak in mid-morning and a major peak at dusk (76.4% caught between 1800 and 2200 h). The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed. A model selection procedure indicated that the four abiotic factors collectively and interactively governed P. juglandis diurnal flight. For both sexes, flight peaked under the following second-order interactions among the factors when: 1) temperature between was 25 and 30 °C and light intensity was less than 2000 lux; 2) temperature was between 25 and 35 °C and barometric pressure was between 752 and 762 mba (and declined otherwise); 3) barometric pressure was between 755 and 761 mba and light intensity was less than 2000 lux (and declined otherwise); and 4) temperature was ca. 30 °C and wind speed was ca. 2 km/h. Thus, crepuscular flight activity of this insect can be best explained by the coincidence of moderately high temperature, low light intensity, moderate wind speed, and low to moderate barometric pressure. The new knowledge provides physical and temporal guidelines for the application of semiochemical-based control techniques as part of an IPM program for this

  12. Impact of abiotic factor changes in blowfly, Achoetandrus rufifacies (Diptera: Calliphoridae), in northern Thailand.

    PubMed

    Klong-Klaew, Tunwadee; Sukontason, Kom; Ngoen-klan, Ratchadawan; Moophayak, Kittikhun; Irvine, Kim N; Kurahashi, Hiromu; Prangkio, Chira; Sanit, Sangob; Sukontason, Kabkaew L

    2014-04-01

    Understanding how medically important flies respond to abiotic factor changes is necessary for predicting their population dynamics. In this study, we investigated the geographical distribution of the medically important blowfly, Achoetandrus rufifacies (Macquart) (Diptera: Calliphoridae), and ascertained the response to climatic and physio-environmental factors in Chiang Mai, northern Thailand. Adult fly surveys were carried out every 2 weeks from May 2009 to May 2010 at 18 systematically randomized study sites in three districts of Chiang Mai province (Mueang Chiang Mai, Mae Rim, and Hang Dong), using reconstructable funnel traps with 1-day tainted beef offal as bait. During the study period, 8,861 adult A. rufifacies were captured, with peak densities being observed at the end of winter (i.e., late February) and throughout most of the summer (May to March). Population density had a weak but significant (α = 0.05) positive correlation with temperature (r = 0.329) and light intensity (r = 0.231), and a weak but significant (α = 0.05) negative correlation with relative humidity (r = -0.236). From the six ecological land use types (disturbed mixed deciduous forest, mixed deciduous forest, mixed orchard, lowland village, city town, and paddy field), greater fly densities were observed generally in the disturbed mixed deciduous forest and lowland village, but not in the paddy fields. In conclusion, A. rufifacies are abundant from the end of winter and throughout most of the summer in northern Thailand, with population density being weakly positively correlated with temperature and light intensity, but weakly negatively correlated with relative humidity. The greatest densities of this fly species were collected in disturbed mixed deciduous forest and lowland village land uses. The prediction of annual and season specific distributions of A. rufifacies were provided in each season and all-year patterns using a co-kriging approach (ArcGIS9.2).

  13. Abiotic Factors Affecting the Persistence of Avian Influenza Virus in Surface Waters of Waterfowl Habitats

    PubMed Central

    Dalton, Melinda S.; Cressler, Alan M.; Berghaus, Roy D.; Stallknecht, David E.

    2014-01-01

    Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-μm filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats. PMID:24584247

  14. Spatial variation in abiotic and biotic factors in a floodplain determine anuran body size and growth rate at metamorphosis.

    PubMed

    Indermaur, Lukas; Schmidt, Benedikt R; Tockner, Klement; Schaub, Michael

    2010-07-01

    Body size at metamorphosis is a critical trait in the life history of amphibians. Despite the wide-spread use of amphibians as experimental model organisms, there is a limited understanding of how multiple abiotic and biotic factors affect the variation in metamorphic traits under natural conditions. The aim of our study was to quantify the effects of abiotic and biotic factors on spatial variation in the body size of tadpoles and size at metamorphosis of the European common toad (Bufo b. spinosus). Our study population was distributed over the riverbed (active tract) and the fringing riparian forest of a natural floodplain. The riverbed had warm ponds with variable hydroperiod and few predators, whereas the forest had ponds with the opposite characteristics. Spatial variation in body size at metamorphosis was governed by the interactive effects of abiotic and biotic factors. The particular form of the interaction between water temperature and intraspecific tadpole density suggests that abiotic factors laid the foundation for biotic factors: intraspecific density decreased growth only at high temperature. Predation and intraspecific density jointly reduced metamorphic size. Interspecific density had a negligible affect on body size at metamorphosis, suggesting weak inter-anuran interactions in the larval stage. Population density at metamorphosis was about one to two orders of magnitudes higher in the riverbed ponds than in the forest ponds, mainly because of lower tadpole mortality. Based on our results, we conclude that ponds in the riverbed appear to play a pivotal role for the population because tadpole growth and survival is best in this habitat.

  15. Combined Effects of Soil Biotic and Abiotic Factors, Influenced by Sewage Sludge Incorporation, on the Incidence of Corn Stalk Rot

    PubMed Central

    Fortes, Nara Lúcia Perondi; Navas-Cortés, Juan A; Silva, Carlos Alberto; Bettiol, Wagner

    2016-01-01

    The objectives of this study were to evaluate the combined effects of soil biotic and abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two types of sewage sludge into soil in a 5-years field assay under tropical conditions and to predict the effects of these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. A multiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil. PMID:27176597

  16. Effects of biotic and abiotic factors on the distribution of trout and salmon along a longitudinal stream gradient

    USGS Publications Warehouse

    De La, Hoz; Budy, P.

    2005-01-01

    We examined the influence of biotic and abiotic factors on the distribution, abundance, and condition of salmonid fishes along a stream gradient. We observed a longitudinal change in fish distribution with native cutthroat trout, Oncorhynchus clarki utah, and introduced brown trout, Salmo trutta, demonstrating a distinct pattern of allopatry. Cutthroat trout dominated high elevation reaches, while reaches at lower elevations were dominated by brown trout. A transition zone between these populations was associated with lower total trout abundance, consistent changes in temperature and discharge, and differences in dietary preference. Variation in cutthroat trout abundance was best explained by a model including the abundance of brown trout and diel temperature, whereas variation in brown trout abundance was best explained by a model including the abundance of cutthroat trout and discharge. These results suggest the potential for condition-mediated competition between the two species. The results from our study can aid biologists in prioritizing conservation activities and in developing robust management strategies for cutthroat trout. ?? Springer 2005.

  17. Combined Effects of Soil Biotic and Abiotic Factors, Influenced by Sewage Sludge Incorporation, on the Incidence of Corn Stalk Rot.

    PubMed

    Ghini, Raquel; Fortes, Nara Lúcia Perondi; Navas-Cortés, Juan A; Silva, Carlos Alberto; Bettiol, Wagner

    2016-01-01

    The objectives of this study were to evaluate the combined effects of soil biotic and abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two types of sewage sludge into soil in a 5-years field assay under tropical conditions and to predict the effects of these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. A multiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil.

  18. Vascular plant one-zinc-finger protein 1/2 transcription factors regulate abiotic and biotic stress responses in Arabidopsis.

    PubMed

    Nakai, Yusuke; Nakahira, Yoichi; Sumida, Hiroki; Takebayashi, Kosuke; Nagasawa, Yumiko; Yamasaki, Kanako; Akiyama, Masako; Ohme-Takagi, Masaru; Fujiwara, Sumire; Shiina, Takashi; Mitsuda, Nobutaka; Fukusaki, Eiichiro; Kubo, Yasuyuki; Sato, Masa H

    2013-03-01

    Plants adapt to abiotic and biotic stresses by activating abscisic acid-mediated (ABA) abiotic stress-responsive and salicylic acid-(SA) or jasmonic acid-mediated (JA) biotic stress-responsive pathways, respectively. Although the abiotic stress-responsive pathway interacts antagonistically with the biotic stress-responsive pathways, the mechanisms that regulate these pathways remain largely unknown. In this study, we provide insight into the function of vascular plant one-zinc-finger proteins (VOZs) that modulate various stress responses in Arabidopsis. The expression of many stress-responsive genes was changed in the voz1voz2 double mutant under normal growth conditions. Consistent with altered stress-responsive gene expression, freezing- and drought-stress tolerances were increased in the voz1voz2 double mutant. In contrast, resistance to a fungal pathogen, Colletotrichum higginsianum, and to a bacterial pathogen, Pseudomonas syringae, was severely impaired. Thus, impairing VOZ function simultaneously conferred increased abiotic tolerance and biotic stress susceptibility. In a chilling stress condition, both the VOZ1 and VOZ2 mRNA expression levels and the VOZ2 protein level gradually decreased. VOZ2 degradation during cold exposure was completely inhibited by the addition of the 26S proteasome inhibitor, MG132, a finding that suggested that VOZ2 degradation is dependent on the ubiquitin/26S proteasome system. In voz1voz2, ABA-inducible transcription factor CBF4 expression was enhanced significantly even under normal growth conditions, despite an unchanged endogenous ABA content. A finding that suggested that VOZs negatively affect CBF4 expression in an ABA-independent manner. These results suggest that VOZs function as both negative and positive regulators of the abiotic and biotic stress-responsive pathways, and control Arabidopsis adaptation to various stress conditions.

  19. Molecular characterization of BZR transcription factor family and abiotic stress induced expression profiling in Brassica rapa.

    PubMed

    Saha, Gopal; Park, Jong-In; Jung, Hee-Jeong; Ahmed, Nasar Uddin; Kayum, Md Abdul; Kang, Jong-Goo; Nou, Ill-Sup

    2015-07-01

    BRASSINAZOLE-RESISTANT (BZR) transcription factors (TFs) are primarily well known as positive regulators of Brassinosteroid (BR) signal transduction in different plants. BR is a plant specific steroid hormone, which has multiple stress resistance functions besides various growth regulatory roles. Being an important regulator of the BR synthesis, BZR TFs might have stress resistance related activities. However, no stress resistance related functional study of BZR TFs has been reported in any crop plants so far. Therefore, this study identified 15 BZR TFs of Brassica rapa (BrBZR) from a genome-wide survey and characterized them through sequence analysis and expression profiling against several abiotic stresses. Various systematic in silico analysis of these TFs validated the fundamental properties of BZRs, where a high degree of similarity also observed with recognized BZRs of other plant species from the comparison studies. In the organ specific expression analyses, 6 BrBZR TFs constitutively expressed in flower developmental stages indicating their flower specific functions. Subsequently, from the stress resistance related expression profiles differential transcript abundance levels were observed by 6 and 11 BrBZRs against salt and drought stresses, respectively. All BrBZRs showed several folds up-regulation against exogenous ABA treatment. All BrBZRs also showed differential expression against low temperature stress treatments and these TFs were proposed as transcriptional activators of CBF cold response pathway of B. rapa. Notably, three BrBZRs gave co-responsive expression against all the stresses tested here, suggesting their multiple stress resistance related functions. Thus, the findings would be helpful in resolving the complex regulatory mechanism of BZRs in stress resistance and further functional genomics study of these potential TFs in different Brassica crops.

  20. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory.

    PubMed

    Wang, Ce; Bi, Jun; Fath, Brian D

    2017-02-21

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

  1. Seasonal dynamics of wheat aphid complex and predator Coccinella septempunctata in relation to abiotic and biotic factors.

    PubMed

    Soni, Rajesh; Deol, G S; Singh, Satnam

    2013-07-01

    Seasonal dynamics studies on wheat aphid complex, comprising of four major species and its predator Coccinella septempunctata were conducted in context to abiotic and biotic factors. The alate form of aphids appeared on the crop during the 1st week of December. The colony build up of aphid complex started during the 2nd week of January and peak was observed after the 1st week of March. Wheat aphid complex started declining in the last week of March and disappeared by mid April. The abiotic factors like maximum temperature and evaporation were most important for the build up of aphids. The grubs and adults of C. septempunctata appeared on the crop during mid February and their population increased with the increase in aphid population. The grubs and adult population showed a strong positive correlation with aphid complex. The population of predators had significant positive correlation with maximum, minimum, mean temperature, sunshine and vapour pressure. The population of aphids declined after the 2nd week of March due to the rise in temperature, crop maturity and this in turn resulted in the lowering of the predator population. The studies evaluate in detail the abiotic and biotic factors regulating the wheat aphid complex and C. septempunctata populations under wheat agro-ecosystem.

  2. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

    NASA Astrophysics Data System (ADS)

    Wang, Ce; Bi, Jun; Fath, Brian D.

    2017-02-01

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

  3. Developing standards for environmental toxicants: the need to consider abiotic environmental factors and microbe-mediated ecologic processes.

    PubMed Central

    Babich, H; Stotzky, G

    1983-01-01

    This article suggests and discusses two novel aspects for the formulation of standards for environmental toxicants. First, uniform national standards for each pollutant will be underprotective for some ecosystems and overprotective for others, inasmuch as the toxicity of a pollutant to the indigenous biota is dependent on the physicochemical properties of the recipient environment. As the number of chemicals that need regulation is immense and as microbes appear to respond similarly to pollutant-abiotic factor interactions as do plants and animals, it is suggested that microbial assays be used initially to identify those abiotic factors that most influence the toxicity of specific pollutants. Thereafter, additional studies using plants and animals can focus on these pollutant-abiotic factor interactions, and more meaningful standards can then be formulated more rapidly and inexpensively. Second, it is suggested that the response to pollutants of microbe-mediated ecologic processes be used to quantitate the sensitivity of different ecosystems to various toxicants. Such a quantification, expressed in terms of an "ecological dose 50%" (EcD50), could be easily incorporated into the methodologies currently used to set water quality criteria and would also be applicable to setting criteria for terrestrial ecosystems. PMID:6339225

  4. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

    PubMed Central

    Wang, Ce; Bi, Jun; Fath, Brian D.

    2017-01-01

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained. PMID:28220835

  5. Expression of the MYB transcription factor gene BplMYB46 affects abiotic stress tolerance and secondary cell wall deposition in Betula platyphylla.

    PubMed

    Guo, Huiyan; Wang, Yucheng; Wang, Liuqiang; Hu, Ping; Wang, Yanmin; Jia, Yuanyuan; Zhang, Chunrui; Zhang, Yu; Zhang, Yiming; Wang, Chao; Yang, Chuanping

    2017-01-01

    Plant MYB transcription factors control diverse biological processes, such as differentiation, development and abiotic stress responses. In this study, we characterized BplMYB46, an MYB gene from Betula platyphylla (birch) that is involved in both abiotic stress tolerance and secondary wall biosynthesis. BplMYB46 can act as a transcriptional activator in yeast and tobacco. We generated transgenic birch plants with overexpressing or silencing of BplMYB46 and subjected them to gain- or loss-of-function analysis. The results suggest that BplMYB46 improves salt and osmotic tolerance by affecting the expression of genes including SOD, POD and P5CS to increase both reactive oxygen species scavenging and proline levels. In addition, BplMYB46 appears to be involved in controlling stomatal aperture to reduce water loss. Overexpression of BplMYB46 increases lignin deposition, secondary cell wall thickness and the expression of genes in secondary cell wall formation. Further analysis indicated that BplMYB46 binds to MYBCORE and AC-box motifs and may directly activate the expression of genes involved in abiotic stress responses and secondary cell wall biosynthesis whose promoters contain these motifs. The transgenic BplMYB46-overexpressing birch plants, which have improved salt and osmotic stress tolerance, higher lignin and cellulose content and lower hemicellulose content than the control, have potential applications in the forestry industry.

  6. Kresoxim-methyl primes Medicago truncatula plants against abiotic stress factors via altered reactive oxygen and nitrogen species signalling leading to downstream transcriptional and metabolic readjustment

    PubMed Central

    Filippou, Panagiota; Antoniou, Chrystalla; Obata, Toshihiro; Van Der Kelen, Katrien; Harokopos, Vaggelis; Kanetis, Loukas; Aidinis, Vassilis; Van Breusegem, Frank; Fernie, Alisdair R; Fotopoulos, Vasileios

    2016-01-01

    Biotic and abiotic stresses, such as fungal infection and drought, cause major yield losses in modern agriculture. Kresoxim-methyl (KM) belongs to the strobilurins, one of the most important classes of agricultural fungicides displaying a direct effect on several plant physiological and developmental processes. However, the impact of KM treatment on salt and drought stress tolerance is unknown. In this study we demonstrate that KM pre-treatment of Medicago truncatula plants results in increased protection to drought and salt stress. Foliar application with KM prior to stress imposition resulted in improvement of physiological parameters compared with stressed-only plants. This protective effect was further supported by increased proline biosynthesis, modified reactive oxygen and nitrogen species signalling, and attenuation of cellular damage. In addition, comprehensive transcriptome analysis identified a number of transcripts that are differentially accumulating in drought- and salinity-stressed plants (646 and 57, respectively) after KM pre-treatment compared with stressed plants with no KM pre-treatment. Metabolomic analysis suggests that the priming role of KM in drought- and to a lesser extent in salinity-stressed plants can be attributed to the regulation of key metabolites (including sugars and amino acids) resulting in protection against abiotic stress factors. Overall, the present study highlights the potential use of this commonly used fungicide as a priming agent against key abiotic stress conditions. PMID:26712823

  7. Kresoxim-methyl primes Medicago truncatula plants against abiotic stress factors via altered reactive oxygen and nitrogen species signalling leading to downstream transcriptional and metabolic readjustment.

    PubMed

    Filippou, Panagiota; Antoniou, Chrystalla; Obata, Toshihiro; Van Der Kelen, Katrien; Harokopos, Vaggelis; Kanetis, Loukas; Aidinis, Vassilis; Van Breusegem, Frank; Fernie, Alisdair R; Fotopoulos, Vasileios

    2016-03-01

    Biotic and abiotic stresses, such as fungal infection and drought, cause major yield losses in modern agriculture. Kresoxim-methyl (KM) belongs to the strobilurins, one of the most important classes of agricultural fungicides displaying a direct effect on several plant physiological and developmental processes. However, the impact of KM treatment on salt and drought stress tolerance is unknown. In this study we demonstrate that KM pre-treatment of Medicago truncatula plants results in increased protection to drought and salt stress. Foliar application with KM prior to stress imposition resulted in improvement of physiological parameters compared with stressed-only plants. This protective effect was further supported by increased proline biosynthesis, modified reactive oxygen and nitrogen species signalling, and attenuation of cellular damage. In addition, comprehensive transcriptome analysis identified a number of transcripts that are differentially accumulating in drought- and salinity-stressed plants (646 and 57, respectively) after KM pre-treatment compared with stressed plants with no KM pre-treatment. Metabolomic analysis suggests that the priming role of KM in drought- and to a lesser extent in salinity-stressed plants can be attributed to the regulation of key metabolites (including sugars and amino acids) resulting in protection against abiotic stress factors. Overall, the present study highlights the potential use of this commonly used fungicide as a priming agent against key abiotic stress conditions.

  8. Effect of abiotic factors on the mercury reduction process by humic acids in aqueous systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mercury (Hg) in the environment can have serious toxic effects on a variety of living organisms, and is a pollutant of concern worldwide. The reduction of mercury from the toxic Hg2+ form to Hg0 is especially important. One pathway for this reduction to occur is through an abiotic process with humic...

  9. Interactions of biotic and abiotic environmental factors in an ectomycorrhizal symbiosis, and the potential for selection mosaics

    PubMed Central

    Piculell, Bridget J; Hoeksema, Jason D; Thompson, John N

    2008-01-01

    Background Geographic selection mosaics, in which species exert different evolutionary impacts on each other in different environments, may drive diversification in coevolving species. We studied the potential for geographic selection mosaics in plant-mycorrhizal interactions by testing whether the interaction between bishop pine (Pinus muricata D. Don) and one of its common ectomycorrhizal fungi (Rhizopogon occidentalis Zeller and Dodge) varies in outcome, when different combinations of plant and fungal genotypes are tested under a range of different abiotic and biotic conditions. Results We used a 2 × 2 × 2 × 2 factorial experiment to test the main and interactive effects of plant lineage (two maternal seed families), fungal lineage (two spore collections), soil type (lab mix or field soil), and non-mycorrhizal microbes (with or without) on the performance of plants and fungi. Ecological outcomes, as assessed by plant and fungal performance, varied widely across experimental environments, including interactions between plant or fungal lineages and soil environmental factors. Conclusion These results show the potential for selection mosaics in plant-mycorrhizal interactions, and indicate that these interactions are likely to coevolve in different ways in different environments, even when initially the genotypes of the interacting species are the same across all environments. Hence, selection mosaics may be equally as effective as genetic differences among populations in driving divergent coevolution among populations of interacting species. PMID:18507825

  10. Transcriptional profiling of Medicago truncatula under salt stress identified a novel CBF transcription factor MtCBF4 that plays an important role in abiotic stress responses

    PubMed Central

    2011-01-01

    Background Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. Results A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Conclusion Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants. PMID:21718548

  11. Transcriptome-Based Analysis of Dof Family Transcription Factors and Their Responses to Abiotic Stress in Tea Plant (Camellia sinensis).

    PubMed

    Li, Hui; Huang, Wei; Liu, Zhi-Wei; Wang, Yong-Xin; Zhuang, Jing

    2016-01-01

    Tea plant (Camellia sinensis (L.) O. Kuntze) is affected by abiotic stress during its growth and development. DNA-binding with one finger (Dof) transcription factors (TFs) play important roles in abiotic stress tolerance of plants. In this study, a total of 29 putative Dof TFs were identified based on transcriptome of tea plant, and the conserved domains and common motifs of these CsDof TFs were predicted and analyzed. The 29 CsDof proteins were divided into 7 groups (A, B1, B2, C1, C2.1, C2.2, and D2), and the interaction networks of Dof proteins in C. sinensis were established according to the data in Arabidopsis. Gene expression was analyzed in "Yingshuang" and "Huangjinya" under four experimental stresses by qRT-PCR. CsDof genes were expressed differentially and related to different abiotic stress conditions. In total, our results might suggest that there is a potential relationship between CsDof factors and tea plant stress resistance.

  12. Transcriptome-Based Analysis of Dof Family Transcription Factors and Their Responses to Abiotic Stress in Tea Plant (Camellia sinensis)

    PubMed Central

    Li, Hui; Huang, Wei; Liu, Zhi-Wei; Wang, Yong-Xin

    2016-01-01

    Tea plant (Camellia sinensis (L.) O. Kuntze) is affected by abiotic stress during its growth and development. DNA-binding with one finger (Dof) transcription factors (TFs) play important roles in abiotic stress tolerance of plants. In this study, a total of 29 putative Dof TFs were identified based on transcriptome of tea plant, and the conserved domains and common motifs of these CsDof TFs were predicted and analyzed. The 29 CsDof proteins were divided into 7 groups (A, B1, B2, C1, C2.1, C2.2, and D2), and the interaction networks of Dof proteins in C. sinensis were established according to the data in Arabidopsis. Gene expression was analyzed in “Yingshuang” and “Huangjinya” under four experimental stresses by qRT-PCR. CsDof genes were expressed differentially and related to different abiotic stress conditions. In total, our results might suggest that there is a potential relationship between CsDof factors and tea plant stress resistance. PMID:27872842

  13. The soybean GmbZIP1 transcription factor enhances multiple abiotic stress tolerances in transgenic plants.

    PubMed

    Gao, Shi-Qing; Chen, Ming; Xu, Zhao-Shi; Zhao, Chang-Ping; Li, Liancheng; Xu, Hui-jun; Tang, Yi-miao; Zhao, Xin; Ma, You-Zhi

    2011-04-01

    Abscisic acid (ABA)-responsive element binding proteins (AREBs) are basic domain/leucine zipper transcription factors that bind to the ABA-responsive element (ABRE) in the promoter regions of ABA-inducible genes in plants. A novel bZIP transcription factor gene, GmbZIP1, encoding 438 amino acids with a conserved bZIP domain composed of 60 amino acids was isolated from salt-tolerant soybean cv. Tiefeng 8. Southern blotting showed that only one copy was present in the soybean genome. Phylogenetic analyses showed that GmbZIP1 belonged to the AREB subfamily of the bZIP family and was most closely related to AtABF2 and OsTRAB1. The expression of GmbZIP1 was highly induced by ABA, drought, high salt and low temperature; and GmbZIP1 was expressed in soybean roots, stems and leaves under different stress conditions. GmbZIP1 was localized inside the nuclei of transformed onion epidermal cells. Overexpression of GmbZIP1 enhanced the responses of transgenic plants to ABA and triggered stomatal closure under stresses, potentially leading to improved tolerances to several abiotic stresses such as high salt, low temperature and drought in transgenic plants. Furthermore, overexpression of GmbZIP1 affected the expression of some ABA or stress-related genes involved in regulating stomatal closure in Arabidopsis under ABA, drought and high salt stress conditions. A few AREB elements were detected in the promoter region of those ABA or stress-related genes, suggesting that GmbZIP1 regulates the ABA response or stomatal closure mediated by those downstream genes in transgenic Arabidopsis. Moreover, GmbZIP1 was used to improve the drought tolerance trait of Chinese wheat varieties BS93. Functional analysis showed that overexpression of GmbZIP1 enhanced the drought tolerance of transgenic wheat, and transcripts of GmbZIP1 were detected in transgenic wheat using RT-PCR. In addition, GmbZIP1 overexpression did not result in growth retardation in all transgenic plants, suggesting that Gmb

  14. Variation in stability of elk and red deer populations with abiotic and biotic factors at the species-distribution scale.

    PubMed

    Ahrestani, Farshid S; Smith, William K; Hebblewhite, Mark; Running, Steven; Post, Eric

    2016-11-01

    abiotic conditions, both reduce stability, but in opposing fashion: one through weakened direct density dependence and the other through strengthened delayed density dependence. Importantly, however, no single abiotic or biotic environmental factor emerged as generally predictive of the strengths of direct or delayed density dependence, nor of the stability properties emerging from their interaction. Our results emphasize the challenges inherent to ascribing primacy to drivers of such parameters at the species level and distribution scale.

  15. A novel wheat bZIP transcription factor, TabZIP60, confers multiple abiotic stress tolerances in transgenic Arabidopsis.

    PubMed

    Zhang, Lina; Zhang, Lichao; Xia, Chuan; Zhao, Guangyao; Liu, Ji; Jia, Jizeng; Kong, Xiuying

    2015-04-01

    The basic region/leucine zipper (bZIP) transcription factors (TFs) play vital roles in the response to abiotic stress. However, little is known about the function of bZIP genes in wheat abiotic stress. In this study, we report the isolation and functional characterization of the TabZIP60 gene. Three homologous genome sequences of TabZIP60 were isolated from hexaploid wheat and mapped to the wheat homoeologous group 6. A subcellular localization analysis indicated that TabZIP60 is a nuclear-localized protein that activates transcription. Furthermore, TabZIP60 gene transcripts were strongly induced by polyethylene glycol, salt, cold and exogenous abscisic acid (ABA) treatments. Further analysis showed that the overexpression of TabZIP60 in Arabidopsis resulted in significantly improved tolerances to drought, salt, freezing stresses and increased plant sensitivity to ABA in seedling growth. Meanwhile, the TabZIP60 was capable of binding ABA-responsive cis-elements that are present in promoters of many known ABA-responsive genes. A subsequent analysis showed that the overexpression of TabZIP60 led to enhanced expression levels of some stress-responsive genes and changes in several physiological parameters. Taken together, these results suggest that TabZIP60 enhances multiple abiotic stresses through the ABA signaling pathway and that modifications of its expression may improve multiple stress tolerances in crop plants.

  16. Influence of Various Levels of Iron and Other Abiotic Factors on Siderophorogenesis in Paddy Field Cyanobacterium Anabaena oryzae.

    PubMed

    Singh, Anumeha; Mishra, Arun Kumar

    2015-05-01

    Siderophore production in Anabaena oryzae was investigated under the influence of various levels of iron and other abiotic factors such as pH, temperature, light and different nitrogen sources. Optimization of culture conditions under controlled mechanisms of these abiotic factors lead to the siderophore production in significant amount. Under iron-starved condition, A. oryzae extracellularly releases 89.17% hydroxymate-type siderophore. Slightly alkaline pH and 30 °C temperature was found stimulatory for the cyanobacterial growth and siderophorogenesis (88.52% SU and 83.87% SU, respectively). Excess iron loading had a negative impact on siderophore production along with the alterations in the morphology and growth. Further, scanning electron microphotographs signified that higher concentrations of iron lead to complete damage of the cells and alterations in membrane proteins possibly transporters responsible for exchange of siderophore complex from environment to the cell. SDS-PAGE analysis of whole cell proteins showed overexpression of low molecular weight proteins ranges between 20.1 to 29.0 kDa up to 100-μM iron concentrations. These polypeptides/proteins might be involved in maintaining iron homeostasis by regulating siderophore production. Results suggest that lower concentrations of iron ≤ 50 μM along with other abiotic factors are stimulatory, whereas higher concentrations (>50 μM) are toxic. Data further suggested that cyanobacterium A. oryzae can serve as a potential biofertilizer especially in iron-rich soil through sequestration by the power of natural Fe(III)-siderophore complex formation.

  17. Factors controlling the abiotic photo-degradation of monomethylmercury in surface waters

    NASA Astrophysics Data System (ADS)

    Black, Frank J.; Poulin, Brett A.; Flegal, A. Russell

    2012-05-01

    Photo-decomposition is among the most important mechanisms responsible for degrading monomethylmercury (MMHg) in aquatic systems, but this process is not fully understood. We investigated the relative importance of different factors in controlling the rate of MMHg photo-decomposition in surface waters in experiments using DOM isolated from natural waters. We found no evidence of net abiotic production of MMHg in any dark or light exposed treatments. The average (mean ± s.d.) MMHg photo-decomposition rate constant for all light exposed samples using DOM concentrated from three coastal wetlands was 0.0099 ± 0.0020 E-1m2 (range of 0.006-0.015 E-1m2) when expressed in photon flux from 330-700 nm. This was roughly 3-fold higher than the average MMHg photo-decomposition rate constant in coastal seawater of 0.0032 ± 0.0010 E-1m2. MMHg photo-degradation was highly wavelength dependent. The ratio of MMHg photo-decomposition rate constants, with respect to photon flux, was 400:37:1 for UVB:UVA:PAR. However, when integrated across the entire water column over which MMHg photo-demethylation occurs, PAR was responsible for photo-degrading more MMHg than UVB and UVA combined in the three wetland sites because of the more rapid attenuation of UV light with depth. MMHg half-lives in the wetlands were calculated for the upper 250 cm where photo-degradation occurred, and ranged from 7.6 to 20 days under typical summer sunlight conditions at 37°N. Rates of MMHg photo-decomposition decreased with increasing salinity, and were 27% higher at a salinity of 5 than those at a salinity of 25. This difference could not be accounted for by changes in the complexation of MMHg by DOM and chloride. Differences in MMHg photo-degradation rate constants of up to 18% were measured between treatments using DOM concentrated from three different wetlands. Surprisingly, increasing DOM concentration from 1.5 to 11.3 mg OC L-1 had only a small (6%) effect on MMHg photo-decomposition, which was much

  18. A wheat salinity-induced WRKY transcription factor TaWRKY93 confers multiple abiotic stress tolerance in Arabidopsis thaliana.

    PubMed

    Qin, Yuxiang; Tian, Yanchen; Liu, Xiuzhi

    2015-08-21

    Wheat is an important crop in the world. But most of the cultivars are salt sensitive, and often adversely affected by salt stress. WRKY transcription factors play a major role in plant responses to salt stress, but the effective salinity regulatory WRKYs identified in bread wheat are limited and the mechanism of salt stress tolerance is also not well explored. Here, we identified a salt (NaCl) induced class II WRKY transcription factor TaWRKY93. Its transcript level was strongly induced by salt (NaCl) and exogenous abscisic acid (ABA). Over-expression of TaWRKY93 in Arabidopsis thaliana enhanced salt (NaCl), drought, low temperature and osmotic (mannitol) stress tolerance, mainly demonstrated by transgenic plants forming longer primary roots or more lateral roots on MS plates supplemented with NaCl and mannitol individually, higher survival rate under drought and low temperature stress. Further, transgenic plants maintained a more proline content, higher relative water content and less electrolyte leakage than the wild type plants. The transcript abundance of a series of abiotic stress-related genes was up-regulated in the TaWRKY93 transgenic plants. In summary, TaWRKY93 is a new positive regulator of abiotic stress, it may increase salinity, drought and low temperature stress tolerance through enhancing osmotic adjustment, maintaining membrane stability and increasing transcription of stress related genes, and contribute to the superior agricultural traits of SR3 through promoting root development. It can be used as a candidate gene for wheat transgenic engineering breeding against abiotic stress.

  19. Impact of biotic and abiotic factors on the expression of fungal effector-encoding genes in axenic growth conditions.

    PubMed

    Meyer, Michel; Bourras, Salim; Gervais, Julie; Labadie, Karine; Cruaud, Corinne; Balesdent, Marie-Hélène; Rouxel, Thierry

    2017-02-01

    In phytopathogenic fungi, the expression of hundreds of small secreted protein (SSP)-encoding genes is induced upon primary infection of plants while no or a low level of expression is observed during vegetative growth. In some species such as Leptosphaeria maculans, this coordinated in-planta upregulation of SSP-encoding genes expression relies on an epigenetic control but the signals triggering gene expression in-planta are unknown. In the present study, biotic and abiotic factors that may relieve suppression of SSP-encoding gene expression during axenic growth of L. maculans were investigated. Some abiotic factors (temperature, pH) could have a limited effect on SSP gene expression. In contrast, two types of cellular stresses induced by antibiotics (cycloheximide, phleomycin) activated strongly the transcription of SSP genes. A transcriptomic analysis to cycloheximide exposure revealed that biological processes such as ribosome biosynthesis and rRNA processing were induced whereas important metabolic pathways such as glycogen and nitrogen metabolism, glycolysis and tricarboxylic acid cycle activity were down-regulated. A quantitatively different expression of SSP-encoding genes compared to plant infection was also detected. Interestingly, the same physico-chemical parameters as those identified here for L. maculans effectors were identified to regulate positively or negatively the expression of bacterial effectors. This suggests that apoplastic phytopathogens may react to similar physiological parameters for regulation of their effector genes.

  20. Genome Wide Analysis of the Apple MYB Transcription Factor Family Allows the Identification of MdoMYB121 Gene Confering Abiotic Stress Tolerance in Plants

    PubMed Central

    Wang, Rong-Kai; Zhang, Rui-Fen; Hao, Yu-Jin

    2013-01-01

    The MYB proteins comprise one of the largest families of transcription factors (TFs) in plants. Although several MYB genes have been characterized to play roles in secondary metabolism, the MYB family has not yet been identified in apple. In this study, 229 apple MYB genes were identified through a genome-wide analysis and divided into 45 subgroups. A computational analysis was conducted using the apple genomic database to yield a complete overview of the MYB family, including the intron-exon organizations, the sequence features of the MYB DNA-binding domains, the carboxy-terminal motifs, and the chromosomal locations. Subsequently, the expression of 18 MYB genes, including 12 were chosen from stress-related subgroups, while another 6 ones from other subgroups, in response to various abiotic stresses was examined. It was found that several of these MYB genes, particularly MdoMYB121, were induced by multiple stresses. The MdoMYB121 was then further functionally characterized. Its predicted protein was found to be localized in the nucleus. A transgenic analysis indicated that the overexpression of the MdoMYB121 gene remarkably enhanced the tolerance to high salinity, drought, and cold stresses in transgenic tomato and apple plants. Our results indicate that the MYB genes are highly conserved in plant species and that MdoMYB121 can be used as a target gene in genetic engineering approaches to improve the tolerance of plants to multiple abiotic stresses. PMID:23950843

  1. Genome-wide characterization and analysis of bZIP transcription factor gene family related to abiotic stress in cassava

    PubMed Central

    Hu, Wei; Yang, Hubiao; Yan, Yan; Wei, Yunxie; Tie, Weiwei; Ding, Zehong; Zuo, Jiao; Peng, Ming; Li, Kaimian

    2016-01-01

    The basic leucine zipper (bZIP) transcription factor family plays crucial roles in various aspects of biological processes. Currently, no information is available regarding the bZIP family in the important tropical crop cassava. Herein, 77 bZIP genes were identified from cassava. Evolutionary analysis indicated that MebZIPs could be divided into 10 subfamilies, which was further supported by conserved motif and gene structure analyses. Global expression analysis suggested that MebZIPs showed similar or distinct expression patterns in different tissues between cultivated variety and wild subspecies. Transcriptome analysis of three cassava genotypes revealed that many MebZIP genes were activated by drought in the root of W14 subspecies, indicating the involvement of these genes in the strong resistance of cassava to drought. Expression analysis of selected MebZIP genes in response to osmotic, salt, cold, ABA, and H2O2 suggested that they might participate in distinct signaling pathways. Our systematic analysis of MebZIPs reveals constitutive, tissue-specific and abiotic stress-responsive candidate MebZIP genes for further functional characterization in planta, yields new insights into transcriptional regulation of MebZIP genes, and lays a foundation for understanding of bZIP-mediated abiotic stress response. PMID:26947924

  2. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (Hymenoptera: Bethylidae).

    PubMed

    Wang, Xiaoyi; Wei, Ke; Yang, Zhongqi; Jennings, David E; Duan, Jian J

    2016-05-19

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. The percentage of winged female parasitoid progeny increased exponentially with temperature between 20 °C to 30 °C. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes. However, the percentage of male progeny increased significantly with the densities of maternal parasitoids. Our findings highlight the phenotypic partitioning of wing morphology and development in the parasitoid S. pupariae under varied environmental cues, and reveal the most favourable conditions for the production of winged females in this bethylid wasp. It is thus possible to increase winged female parasitoid production for the purposes of biological control by manipulation of biotic and abiotic conditions.

  3. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (Hymenoptera: Bethylidae)

    PubMed Central

    Wang, Xiaoyi; Wei, Ke; Yang, Zhongqi; Jennings, David E.; Duan, Jian J.

    2016-01-01

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. The percentage of winged female parasitoid progeny increased exponentially with temperature between 20 °C to 30 °C. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes. However, the percentage of male progeny increased significantly with the densities of maternal parasitoids. Our findings highlight the phenotypic partitioning of wing morphology and development in the parasitoid S. pupariae under varied environmental cues, and reveal the most favourable conditions for the production of winged females in this bethylid wasp. It is thus possible to increase winged female parasitoid production for the purposes of biological control by manipulation of biotic and abiotic conditions. PMID:27194095

  4. Quantifying components of soil respiration and their response to abiotic factors in two typical subtropical forest stands, southwest China.

    PubMed

    Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

    2015-01-01

    Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (RA) and heterotrophic (RH) in total soil (RT) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.-Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6 cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of RH and RA to RT for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to RT, accounted for over 63% of RH. 3) AT and ST were significantly positively correlated with RT and its components (p<0.05), and were major factors affecting soil respiration. 4) Components of soil respiration were significantly different between two forest stands (p<0.05), indicating that vegetation types played a role in soil respiration and its components.

  5. Influence of biotic and abiotic factors on the allelopathic activity of the cyanobacterium Cylindrospermopsis raciborskii strain LEGE 99043.

    PubMed

    Antunes, Jorge T; Leão, Pedro N; Vasconcelos, Vítor M

    2012-10-01

    Allelopathy is considered to be one of the factors underlying the global expansion of the toxic cyanobacterium Cylindrospermopsis raciborskii. Although the production and release of allelopathic compounds by cyanobacteria is acknowledged to be influenced by environmental parameters, the response of C. raciborskii remains generally unrecognized. Here, the growth and allelopathic potential of C. raciborskii strain LEGE 99043 towards the ubiquitous microalga Ankistrodesmus falcatus were analyzed under different biotic and abiotic conditions. Filtrates from C. raciborskii cultures growing at different cell densities displayed broad inhibitory activity. Moreover, higher temperature, higher light intensity as well phosphate limitation further enhanced this activity. The distinct and comprehensive patterns of inhibition verified during the growth phase, and under the tested parameters, suggest the action of several, still unidentified allelopathic compounds. It is expectable that the observed increase in allelopathic activity can result in distinct ecological advantages to C. raciborskii.

  6. Identification of 30 MYB transcription factor genes and analysis of their expression during abiotic stress in peanut (Arachis hypogaea L.).

    PubMed

    Chen, Na; Yang, Qingli; Pan, Lijuan; Chi, Xiaoyuan; Chen, Mingna; Hu, Dongqing; Yang, Zhen; Wang, Tong; Wang, Mian; Yu, Shanlin

    2014-01-01

    The MYB superfamily constitutes one of the most abundant groups of transcription factors and plays central roles in developmental processes and defense responses in plants. In the work described in this article, 30 unique peanut MYB genes that contained full-length cDNA sequences were isolated. The 30 genes were grouped into three categories: one R1R2R3-MYB, nine R2R3-MYBs and 20 MYB-related members. The sequence composition of the R2 and R3 repeats was conserved among the nine peanut R2R3-MYB proteins. Phylogenetic comparison of the members of this superfamily between peanut and Arabidopsis revealed that the putative functions of some peanut MYB proteins were clustered into the Arabidopsis functional groups. Expression analysis during abiotic stress identified a group of MYB genes that responded to at least one stress treatment. This is the first comprehensive study of the MYB gene family in peanut.

  7. Abiotic factors influencing biomass accumulation of green tide causing Ulva spp. on Pyropia culture rafts in the Yellow Sea, China.

    PubMed

    Keesing, John K; Liu, Dongyan; Shi, Yajun; Wang, Yujue

    2016-04-15

    Annually recurrent green-tides in the Yellow Sea have been shown to result from direct disposal into the sea of fouling Ulva from Pyropia aquaculture. The role abiotic factors play in Ulva biomass accumulation on rafts was studied to find ways to mitigate this problem. Dissolved inorganic nitrogen (DIN) was very high at all sites, but the highest Ulva biomass was associated with the lowest DIN and anthropogenic N. Under luxuriant background nutrient conditions, variability in temperature and periods of emersion, rather than pH, light and salinity determined Ulva biomass. Two dominant species of Ulva displayed differing tolerances to temperature and desiccation which helped explain why Ulva prolifera dominates floating green-tides. Rather than trying to mitigate green-tides only by reducing nutrient pollution, an earlier harvest of Pyropia in southern Jiangsu Province especially before temperatures increase greatly above 10°C during April, could reduce the biomass of U. prolifera disposed from rafts.

  8. EsDREB2B, a novel truncated DREB2-type transcription factor in the desert legume Eremosparton songoricum, enhances tolerance to multiple abiotic stresses in yeast and transgenic tobacco

    PubMed Central

    2014-01-01

    Background Dehydration-Responsive Element-Binding Protein2 (DREB2) is a transcriptional factor which regulates the expression of several stress-inducible genes. DREB2-type proteins are particularly important in plant responses to drought, salt and heat. DREB2 genes have been identified and characterized in a variety of plants, and DREB2 genes are promising candidate genes for the improvement of stress tolerance in plants. However, little is known about these genes in plants adapted to water-limiting environments. Results In this study, we describe the characterization of EsDREB2B, a novel DREB2B gene identified from the desert plant Eremosparton songoricum. Phylogenetic analysis and motif prediction indicate that EsDREB2B encodes a truncated DREB2 polypeptide that belongs to a legume-specific DREB2 group. In E. songoricum, EsDREB2B transcript accumulation was induced by a variety of abiotic stresses, including drought, salinity, cold, heat, heavy metal, mechanical wounding, oxidative stress and exogenous abscisic acid (ABA) treatment. Consistent with the predicted role as a transcription factor, EsDREB2B was targeted to the nucleus of onion epidermal cells and exhibited transactivation activity of a GAL4-containing reporter gene in yeast. In transgenic yeast, overexpression of EsDREB2B increased tolerance to multiple abiotic stresses. Our findings indicate that EsDREB2B can enhance stress tolerance in other plant species. Heterologous expression of EsDREB2B in tobacco showed improved tolerance to multiple abiotic stresses, and the transgenic plants exhibited no reduction in foliar growth. We observed that EsDREB2B is a functional DREB2-orthologue able to influence the physiological and biochemical response of transgenic tobacco to stress. Conclusions Based upon these findings, EsDREB2B encodes an abiotic stress-inducible, transcription factor which confers abiotic stress-tolerance in yeast and transgenic tobacco. PMID:24506952

  9. Three ERF transcription factors from Chinese wild grapevine Vitis pseudoreticulata participate in different biotic and abiotic stress-responsive pathways.

    PubMed

    Zhu, Ziguo; Shi, Jiangli; Xu, Weirong; Li, Huie; He, Mingyang; Xu, Yan; Xu, Tengfei; Yang, Yazhou; Cao, Jiangling; Wang, Yuejin

    2013-07-01

    Ethylene response factor (ERF) functions as an important plant-specific transcription factor in regulating biotic and abiotic stress response through interaction with various stress pathways. We previously obtained three ERF members, VpERF1, VpERF2, and VpERF3 from a highly powdery mildew (PM)-resistant Chinese wild Vitis pseudoreticulata cDNA full-length library. To explore their functions associated with plant disease resistance or biotic stress, we report here to characterize three ERF members from this library. PM-inoculation analysis on three different resistant grapevine genotypes revealed that three VpERFs displayed significant responses, but a different expression pattern. Over-expression of VpERF1, VpERF2, and VpERF3 in transgenic tobacco plants demonstrated that VpERF2 and VpERF3 enhanced resistance to both bacterial pathogen Ralstonia solanacearum and fungal pathogen Phytophtora parasitica var. nicotianae Tucker. Importantly, VpERF1-overexpressing transgenic Arabidopsis plants increased susceptibility toward these pathogens. Investigation on drought, cold, and heat treatments suggested, VpERF2 was distinctly induced, whereas VpERF3 displayed a very weak response and VpERF1 was distinctly induced by drought and heat. Concurrently, VpERF3 was significantly induced by salicylic acid (SA), methyl jasmonate (MeJA), and ET. Our results showed that the three VpERFs from Chinese wild V. pseudoreticulata play different roles in either preventing disease progression via regulating the expression of relevant defense genes, or directly involving abiotic stress responsive pathways.

  10. Effects of biotic and abiotic factors on the oxygen content of green sea turtle nests during embryogenesis.

    PubMed

    Chen, Chiu-Lin; Wang, Chun-Chun; Cheng, I-Jiunn

    2010-10-01

    Several biotic and abiotic factors can influence nest oxygen content during embryogenesis. Several of these factors were determined during each developmental stage of green sea turtle embryos on Wan-an Island, Penghu Archipelago, Taiwan. We examined oxygen content in 7 nests in 2007 and 11 in 2008. Oxygen in the adjacent sand, total and viable clutch sizes, air, sand and nest temperatures, and sand characters of each nest were also determined. Oxygen content was lower in late stages than in the early and middle stages. It was also lower in the middle layer than in the upper and bottom layers. Nest temperature showed opposite trends, reaching its maximum value in late stages of development. Nest oxygen content was influenced by fraction of viable eggs, total clutch sizes, sand temperatures, maximum nest temperature and maximum change in the nest temperature during incubation. Clutch size during embryogenesis was the most influential factor overall. However, the major influential factors were different for different developmental stages. In the first half of the incubation, the development rate was low, and the change in the nest oxygen content was influenced mainly by the clutch size. During the second half, the rapid embryonic development rate became the dominant factor, and hatchling activities caused even greater oxygen consumption during the last stage of development.

  11. Biotic and abiotic factors investigated in two Drosophila species - evidence of both negative and positive effects of interactions on performance.

    PubMed

    Ørsted, Michael; Schou, Mads Fristrup; Kristensen, Torsten Nygaard

    2017-01-06

    Multiple environmental factors acting in concert can interact and strongly influence population fitness and ecosystem composition. Studies investigating interactions usually involve only two environmental factors; most frequently a chemical and another abiotic factor such as a stressful temperature. Here we investigate the effects of three environmental factors: temperature, an insecticide (dimethoate) and interspecific co-occurrence. We expose two naturally co-occurring species of Drosophila (D. hydei and D. melanogaster) to the different environments during development and examine the consequences on several performance measures. Results are highly species and trait specific with evidence of two- and three-way interactions in approximately 30% of all cases, suggesting that additive effects of combined environmental factors are most common, and that interactions are not universal. To provide more informative descriptions of complex interactions we implemented re-conceptualised definitions of synergism and antagonism. We found approximately equal proportions of synergistic and antagonistic interactions in both species, however the effects of interactions on performance differed between the two. Furthermore, we found negative impacts on performance in only 60% of interactions, thus our study also reveals a high proportion of cases with positive effects of interactions.

  12. Improved abiotic stress tolerance of bermudagrass by exogenous small molecules.

    PubMed

    Chan, Zhulong; Shi, Haitao

    2015-01-01

    As a widely used warm-season turfgrass in landscapes and golf courses, bermudagrass encounters multiple abiotic stresses during the growth and development. Physiology analysis indicated that abiotic stresses induced the accumulation of ROS and decline of photosynthesis, resulting in increased cell damage and inhibited growth. Proteomic and metabolomic approaches showed that antioxidant enzymes and osmoprotectant contents (sugar, sucrose, dehydrin, proline) were extensively changed under abiotic stress conditions. Exogenous application of small molecules, such as ABA, NO, CaCl2, H2S, polyamine and melatonin, could effectively alleviate damages caused by multiple abiotic stresses, including drought, salt, heat and cold. Based on high through-put RNA seq analysis, genes involved in ROS, transcription factors, hormones, and carbohydrate metabolisms were largely enriched. The data indicated that small molecules induced the accumulation of osmoprotectants and antioxidants, kept cell membrane integrity, increased photosynthesis and kept ion homeostasis, which protected bermudagrass from damages caused by abiotic stresses.

  13. Novel DREB A-5 subgroup transcription factors from desert moss (Syntrichia caninervis) confers multiple abiotic stress tolerance to yeast.

    PubMed

    Li, Haiyan; Zhang, Daoyuan; Li, Xiaoshuang; Guan, Kaiyun; Yang, Honglan

    2016-05-01

    Syntrichia caninervis Mitt. is a typical desiccation tolerant moss from a temperate desert which has been a good resource for stress tolerant gene isolation. Dehydration responsive element binding proteins (DREBs) was proven to play an important role in responding to abiotic stress, which has been identified in many plants, and were rarely reported in moss. In this study, we cloned ten DREB genes from S. caninervis, and investigated their abiotic stress response and stress tolerance. The results showed that ten ScDREB proteins belonged to the A-5 sub-group of the DREB sub-family. Six genes, ScDREB1, ScDREB2, ScDREB4, ScDREB6, ScDREB7, and ScDREB8 were involved in the ABA-dependent signal pathway and the desiccation, salt, and cold stress response. ScDREB3 also responded to desiccation, salt, and cold stresses, but was insensitive to ABA treatment. Another gene, ScDREB5, was involved in an ABA-independent cold stress-responsive signal pathway. Two genes, ScDREB9 and ScDREB10, responded slightly or had no response to neither stress factor or ABA treatment. We transformed four typical genes into yeast cells and the stress tolerance ability of transgenic yeast was evaluated. The results showed that ScDREB3 and ScDREB5 enhanced the yeast's cold and salt tolerance. ScDREB8 and ScDREB10 conferred the osmotic, salt, cold, and high temperature stresses tolerance, especially for osmotic and salt stresses. Our results indicated that A-5 sub-group DREB genes in S. caninervis played important roles in abiotic stresses response and enhanced stress tolerance to transgenic yeast. To our knowledge, this is the first report on DREB genes characterization from desiccation tolerant moss, and this study will not only provide insight into the molecular mechanisms of S. caninervis adaptation to environmental stresses, but also provides valuable gene candidates for plant molecular breeding.

  14. The SsDREB Transcription Factor from the Succulent Halophyte Suaeda salsa Enhances Abiotic Stress Tolerance in Transgenic Tobacco.

    PubMed

    Zhang, Xu; Liu, Xiaoxue; Wu, Lei; Yu, Guihong; Wang, Xiue; Ma, Hongxiang

    2015-01-01

    Dehydration-responsive element-binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. In this study, a novel cDNA encoding DREB transcription factor, designated SsDREB, was isolated from succulent halophyte Suaeda salsa. This protein was classified in the A-6 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Yeast one-hybrid assays showed that SsDREB protein specifically binds to the DRE sequence and could activate the expression of reporter genes in yeast, suggesting that the SsDREB protein was a CBF/DREB transcription factor. Real-time RT-PCR showed that SsDREB was significantly induced under salinity and drought stress. Overexpression of SsDREB cDNA in transgenic tobacco plants exhibited an improved salt and drought stress tolerance in comparison to the nontransformed controls. The transgenic plants revealed better growth, higher chlorophyll content, and net photosynthesis rate, as well as higher level of proline and soluble sugars. The semiquantitative PCR of transgenics showed higher expression of stress-responsive genes. These data suggest that the SsDREB transcription factor is involved in the regulation of salt stress tolerance in tobacco by the activation of different downstream gene expression.

  15. The SsDREB Transcription Factor from the Succulent Halophyte Suaeda salsa Enhances Abiotic Stress Tolerance in Transgenic Tobacco

    PubMed Central

    Zhang, Xu; Liu, Xiaoxue; Wu, Lei; Yu, Guihong; Wang, Xiue; Ma, Hongxiang

    2015-01-01

    Dehydration-responsive element-binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. In this study, a novel cDNA encoding DREB transcription factor, designated SsDREB, was isolated from succulent halophyte Suaeda salsa. This protein was classified in the A-6 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Yeast one-hybrid assays showed that SsDREB protein specifically binds to the DRE sequence and could activate the expression of reporter genes in yeast, suggesting that the SsDREB protein was a CBF/DREB transcription factor. Real-time RT-PCR showed that SsDREB was significantly induced under salinity and drought stress. Overexpression of SsDREB cDNA in transgenic tobacco plants exhibited an improved salt and drought stress tolerance in comparison to the nontransformed controls. The transgenic plants revealed better growth, higher chlorophyll content, and net photosynthesis rate, as well as higher level of proline and soluble sugars. The semiquantitative PCR of transgenics showed higher expression of stress-responsive genes. These data suggest that the SsDREB transcription factor is involved in the regulation of salt stress tolerance in tobacco by the activation of different downstream gene expression. PMID:26504772

  16. Comparisons of stemflow and its bio-/abiotic influential factors between two xerophytic shrub species

    NASA Astrophysics Data System (ADS)

    Yuan, Chuan; Gao, Guangyao; Fu, Bojie

    2017-03-01

    Stemflow transports nutrient-enriched precipitation to the rhizosphere and functions as an efficient terrestrial flux in water-stressed ecosystems. However, its ecological significance has generally been underestimated because it is relatively limited in amount, and the biotic mechanisms that affect it have not been thoroughly studied at the leaf scale. This study was conducted during the 2014 and 2015 rainy seasons at the northern Loess Plateau of China. We measured the branch stemflow volume (SFb), shrub stemflow equivalent water depth (SFd), stemflow percentage of incident precipitation (SF %), stemflow productivity (SFP), funnelling ratio (FR), the meteorological characteristics and the plant traits of branches and leaves of C. korshinskii and S. psammophila. This study evaluated stemflow efficiency for the first time with the combined results of SFP and FR, and sought to determine the inter- and intra-specific differences of stemflow yield and efficiency between the two species, as well as the specific bio-/abiotic mechanisms that affected stemflow. The results indicated that C. korshinskii had a greater stemflow yield and efficiency at all precipitation levels than that of S. psammophila. The largest inter-specific difference generally occurred at the 5-10 mm branches during rains of ≤ 2 mm. Precipitation amount was the most influential meteorological characteristic that affected stemflow yield and efficiency in these two endemic shrub species. Branch angle was the most influential plant trait on FR. For SFb, stem biomass and leaf biomass were the most influential plant traits for C. korshinskii and S. psammophila, respectively. For SFP of these two shrub species, leaf traits (the individual leaf area) and branch traits (branch size and biomass allocation pattern) had a great influence during lighter rains ≤ 10 mm and heavier rains > 15 mm, respectively. The lower precipitation threshold to start stemflow allowed C. korshinskii (0.9 mm vs. 2

  17. Identification and expression of the WRKY transcription factors of Carica papaya in response to abiotic and biotic stresses.

    PubMed

    Pan, Lin-Jie; Jiang, Ling

    2014-03-01

    The WRKY transcription factor (TF) plays a very important role in the response of plants to various abiotic and biotic stresses. A local papaya database was built according to the GenBank expressed sequence tag database using the BioEdit software. Fifty-two coding sequences of Carica papaya WRKY TFs were predicted using the tBLASTn tool. The phylogenetic tree of the WRKY proteins was classified. The expression profiles of 13 selected C. papaya WRKY TF genes under stress induction were constructed by quantitative real-time polymerase chain reaction. The expression levels of these WRKY genes in response to 3 abiotic and 2 biotic stresses were evaluated. TF807.3 and TF72.14 are upregulated by low temperature; TF807.3, TF43.76, TF12.199 and TF12.62 are involved in the response to drought stress; TF9.35, TF18.51, TF72.14 and TF12.199 is involved in response to wound; TF12.199, TF807.3, TF21.156 and TF18.51 was induced by PRSV pathogen; TF72.14 and TF43.76 are upregulated by SA. The regulated expression levels of above eight genes normalized against housekeeping gene actin were significant at probability of 0.01 levels. These WRKY TFs could be related to corresponding stress resistance and selected as the candidate genes, especially, the two genes TF807.3 and TF12.199, which were regulated notably by four stresses respectively. This study may provide useful information and candidate genes for the development of transgenic stress tolerant papaya varieties.

  18. Perception of Bradyrhizobium japonicum Nod factor by soybean [Glycine max (L.) Merr.] root hairs under abiotic stress conditions.

    PubMed

    Duzan, H M; Zhou, X; Souleimanov, A; Smith, D L

    2004-12-01

    Suboptimal growth conditions, such as low rhizosphere temperature, high salinity, and low pH can negatively affect the rhizobia-legume symbioses, resulting in poor nodulation and lower amounts of nitrogen fixed. Early stages of the Bradyrhizobium japonicum-soybean [Glycine max (L.) Merr.] symbiosis, such as excretion of genistein (the plant-to-bacteria signal) and infection initiation can be inhibited by abiotic stresses; however, the effect on early events modulated by Nod factors (bacteria-to-plant signalling), particularly root hair deformations is unknown. Thus, the objective of this study was to evaluate the perception of Nod factor by soybean root hairs under three stress conditions: low temperature, low pH, and high salinity. Three experiments were conducted using a 1:1 ratio of Nod Bj-V (C(18:1), MeFuc) and Nod Bj-V (Ac, C(16:0), MeFuc). Nod factor induced four types of root hair deformation (HAD), wiggling, bulging, curling, and branching. Under optimal experimental conditions root hair response to the three levels of Nod factor tested (10(-6), 10(-8), and 10(-10) M) was dose-dependent. The highest frequency of root hair deformations was elicited by the 10(-6) M level. Root hair deformation decreased with temperature (25, 17, and 15 degrees C), low pH, and high salinity. Nod factor concentration did not interact with either low temperature or pH. However, salinity strongly inhibited HAD responses to increases in Nod factor concentration. Thus, the addition of higher levels of Nod factor is able to overcome the effects of low pH and temperature stress, but not salinity.

  19. A Wheat WRKY Transcription Factor TaWRKY10 Confers Tolerance to Multiple Abiotic Stresses in Transgenic Tobacco

    PubMed Central

    Chen, Liulin; Wang, Xiatian; Ma, Hui; Hu, Wei; Yao, Ningcong; Feng, Ying; Chai, Ruihong; Yang, Guangxiao; He, Guangyuan

    2013-01-01

    WRKY transcription factors are reported to be involved in defense regulation, stress response and plant growth and development. However, the precise role of WRKY transcription factors in abiotic stress tolerance is not completely understood, especially in crops. In this study, we identified and cloned 10 WRKY genes from genome of wheat (Triticum aestivum L.). TaWRKY10, a gene induced by multiple stresses, was selected for further investigation. TaWRKY10 was upregulated by treatment with polyethylene glycol, NaCl, cold and H2O2. Result of Southern blot indicates that the wheat genome contains three copies of TaWRKY10. The TaWRKY10 protein is localized in the nucleus and functions as a transcriptional activator. Overexpression of TaWRKY10 in tobacco (Nicotiana tabacum L.) resulted in enhanced drought and salt stress tolerance, mainly demonstrated by the transgenic plants exhibiting of increased germination rate, root length, survival rate, and relative water content under these stress conditions. Further investigation showed that transgenic plants also retained higher proline and soluble sugar contents, and lower reactive oxygen species and malonaldehyde contents. Moreover, overexpression of the TaWRKY10 regulated the expression of a series of stress related genes. Taken together, our results indicate that TaWRKY10 functions as a positive factor under drought and salt stresses by regulating the osmotic balance, ROS scavenging and transcription of stress related genes. PMID:23762295

  20. Elasticity of population growth with respect to the intensity of biotic or abiotic driving factors.

    PubMed

    Lee, Charlotte T

    2016-12-19

    Demographic analysis can elucidate how driving factors, such as climate or species interactions,affect populations. One important question is how growth would respond to future changes in the mean intensity of a driving factor or in its variability, such as might be expected in a fluctuating and shifting climate. Here I develop an approach to computing new stochastic elasticities to address this question. The linchpin of this novel approach is the multidimensional demographic difference that expresses how a population responds to change in the driving factor between two discrete levels of intensity. I use this difference to design a perturbation matrix that links data from common empirical sampling schemes with rigorous theory for stochastic elasticities. Although the starting point is a difference, the products of this synthesis are true derivatives: they are elasticity with respect to the mean intensity of a driving factor, and elasticity with respect to variability in a driving factor. Applying the methods to published data, I demonstrate how these new elasticities can shed light on growth rate response within and at the boundary of the previously observed range of the driving factor, thus helpfully indicating nonlinearity in the observed and in the potential future response. The stochastic approach simplifies in a fixed environment, yielding a compact formula for deterministic elasticity to a driving factor. This article is protected by copyright. All rights reserved.

  1. Invasion biology in non-free-living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda, Entocytheridae)

    PubMed Central

    Mestre, Alexandre; Aguilar-Alberola, Josep A; Baldry, David; Balkis, Husamettin; Ellis, Adam; Gil-Delgado, Jose A; Grabow, Karsten; Klobučar, Göran; Kouba, Antonín; Maguire, Ivana; Martens, Andreas; Mülayim, Ayşegül; Rueda, Juan; Scharf, Burkhard; Soes, Menno; S Monrós, Juan; Mesquita-Joanes, Francesc

    2013-01-01

    In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This

  2. Seasonal biotic and abiotic factors affecting hunting strategy in free-living Saharan sand vipers, Cerastes vipera.

    PubMed

    Horesh, Sefi J A; Sivan, Jaim; Rosenstrauch, Avi; Tesler, Itay; Degen, A Allan; Kam, Michael

    2017-02-01

    Sit-and-wait ambushing and active hunting are two strategies used by predators to capture prey. In snakes, hunting strategy is conserved phylogenetically; most species employ only one strategy. Active hunters encounter and capture more prey but invest more energy in hunting and have higher risks of being predated. This trade-off is important to small predators. The small Cerastes vipera employs both modes of hunting, which is unlike most viperids which use only sit-and wait ambushing. This species hibernates in October and emerges in April. Energy intake should be high prior to hibernation to overcome the non-feeding hibernation period and for reproduction on their emergence. We predicted that more individuals would hunt actively towards hibernation and an abiotic factor would trigger this response. Furthermore, since more energy is required for active hunting, we predicted that snakes in good body condition would use active hunting to a greater extent than snakes in poor body condition. To test our predictions, we tracked free-living snakes year round and determined their hunting strategy, estimated their body condition index (BCI), and calculated circannual parameters of day length as environmental cues known to affect animal behaviour. Two novel findings emerged in this study, namely, hunting strategy was affected significantly by 1) the circannual change in day length and 2) by BCI. The proportion of active hunters increased from 5% in April to over 30% in October and BCI of active foragers was higher than that of sit-and-wait foragers and, therefore, our predictions were supported. The entrainment between the proportion of active hunting and the abiotic factor is indicative of an adaptive function for choosing a hunting strategy. A trend was evident among life stages. When all life stages were present (September-October), the proportion of active foragers increased with age: 0.0% among neonates, 18.2% among juveniles and 31.4% among adults. We concluded that

  3. The effect of abiotic factors on the toxicity of cypermethrin against the snail Lymnaea acuminata in the control of fascioliasis.

    PubMed

    Singh, V; Singh, D K

    2009-03-01

    Every month during the year 2006-2007, the 24, 48, 72 and 96 h LC50 values of a molluscicide, cypermethrin, were determined for a snail Lymnaea acuminata, with concomitant estimation of levels of temperature, pH, dissolved oxygen and carbon dioxide and electrical conductivity, both in control and test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values of 10.39, 10.90 and 11.19 mg l- 1 during the months of May, June and July, respectively, were most effective in killing the snails, while the molluscicide was least effective in the month of January, when its 24 h LC50 was 65.84 mg l- 1.There was a significant positive correlation between LC50 of cypermethrin and levels of dissolved O2/pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2/temperature of test water in the same months. In order to ascertain that such a relationship between toxicity and abiotic factors is not coincidental, the nervous tissue of the snail was assayed for the activity of acetylcholinesterase (AChE), acid phosphatase (ACP) and alkaline phosphatase (ALP) to sublethal concentrations (40% and 80%) of 24 h LC50 during each of the 12 months of the same year. The findings confirmed that abiotic factors indeed influence toxicity of cypermethrin in the snail. A significant positive rank correlation between AChE, ACP and ALP activity did exist following exposure to the corresponding sublethal concentrations. Moreover, there was a maximum inhibition of 61.29 and 76.16% of AChE and ACP, respectively, in snails exposed to 80% of the 24 h LC50 in the month of May. A similar treatment caused a maximum inhibition of 70.53% of ALP activity in the month of June. This work shows conclusively that the best time to control the snail population with cypermethrin is during the months of May and June.

  4. Effect of abiotic factors on initiation of red flour beetle (Coleoptera: Tenebrionidae) flight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traps baited with pheromones are used to monitor the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), populations in flour mills to aid in making pest management decisions, but the factors that influence T. castaneum flight aren’t fully understood. We investigated the impa...

  5. Abiotic stresses and endophyte effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abiotic stresses consist of nonorganismal, nonpathogenic factors that inhibit plant function. Tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] is widely symbiotic with a naturally occurring endophytic fungus [Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon, and Hanlin], which con...

  6. Identification and expression of C2H2 transcription factor genes in Carica papaya under abiotic and biotic stresses.

    PubMed

    Jiang, Ling; Pan, Lin-jie

    2012-06-01

    C2H2 proteins belong to a group of transcription factors (TFs) existing as a superfamily that plays important roles in defense responses and various other physiological processes in plants. The present study aimed to screen for and identify C2H2 proteins associated with defense responses to abiotic and biotic stresses in Carica papaya L. Data were collected for 47,483 papaya-expressed sequence tags (ESTs). The full-length cDNA nucleotide sequences of 87 C2H2 proteins were predicated by BioEdit. All 91 C2H2 proteins were aligned, and a phylogenetic tree was constructed using DNAman. The expression levels of 42 C2H2 were analyzed under conditions of salt stress by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Methyl jasmonate treatment rapidly upregulated ZF(23.4) and ZF(30,912.1) by 18.6- and 21.7-fold, respectively. ZF(1.3), ZF(138.44), ZF(94.49), ZF(29.160), and ZF(20.206) were found to be downregulated after low temperature treatment at very significant levels (p < 0.01). ZF(23.4), ZF(161.1), and ZF(30,912.1) were upregulated while ZF1.3, ZF(158.1), ZF(249.5), ZF(138.44), ZF(94.49), ZF(29.160), and ZF(20.206) were significantly downregulated by Spermine treatment. ZF(23.4) was upregulated while ZF(1.3), ZF(249.5), ZF(94.94), ZF(29.160), ZF(138.44), and ZF(20.206) were significantly repressed after SA treatment. ZF(23.4) and ZF(30,912.1) were significantly upregulated after sap inoculation with papaya ringspot virus pathogen. ZF(30,912.1) was subcellularly localized in the nucleus by a transgenic fusion of pBS-ZF(30,912.1)-GFP into the protoplast of papaya. The results of the present study showed that ZF(30,912.1) could be an important TF that mediates responses to abiotic and biotic stresses in papaya.

  7. Dominant repression by Arabidopsis transcription factor MYB44 causes oxidative damage and hypersensitivity to abiotic stress.

    PubMed

    Persak, Helene; Pitzschke, Andrea

    2014-02-13

    In any living species, stress adaptation is closely linked with major changes of the gene expression profile. As a substrate protein of the rapidly stress-induced mitogen-activated protein kinase MPK3, Arabidopsis transcription factor MYB44 likely acts at the front line of stress-induced re-programming. We recently characterized MYB44 as phosphorylation-dependent positive regulator of salt stress signaling. Molecular events downstream of MYB44 are largely unknown. Although MYB44 binds to the MBSII element in vitro, it has no discernible effect on MBSII-driven reporter gene expression in plant co-transfection assays. This may suggest limited abundance of a synergistic co-regulator. MYB44 carries a putative transcriptional repression (Ethylene responsive element binding factor-associated Amphiphilic Repression, EAR) motif. We employed a dominant repressor strategy to gain insights into MYB44-conferred stress resistance. Overexpression of a MYB44-REP fusion markedly compromised salt and drought stress tolerance--the opposite was seen in MYB44 overexpression lines. MYB44-mediated resistance likely results from induction of tolerance-enhancing, rather than from repression of tolerance-diminishing factors. Salt stress-induced accumulation of destructive reactive oxygen species is efficiently prevented in transgenic MYB44, but accelerated in MYB44-REP lines. Furthermore, heterologous overexpression of MYB44-REP caused tissue collapse in Nicotiana. A mechanistic model of MAPK-MYB-mediated enhancement in the antioxidative capacity and stress tolerance is proposed. Genetic engineering of MYB44 variants with higher trans-activating capacity may be a means to further raise stress resistance in crops.

  8. Wind as an abiotic factor of Colorado potato beetle (Coleoptera: Chrysomelidae) flight take-off activity under field conditions.

    PubMed

    Boiteau, G; Mccarthy, P C; MacKinley, P D

    2010-10-01

    The flight take-off activity of Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), was significantly higher at a landscape-protected than at semiexposed and exposed sites in a 2-yr field study. In both years, mean daylight temperature, solar radiation, and relative humidity were generally similar at all sites, but wind speed was lower at the protected site than at the exposed sites. Results suggest that wind was the limiting abiotic factor for flight take-off at the exposed site. Caged beetles exposed to constant wind speeds of 3.4, 4.7, and 7.0 m/s showed a significant corresponding decrease in number of flight take-off. There was no cumulative effect of wind exposure on the readiness of the beetles to fly, suggesting that wind acts as a physical barrier to flight take-off. It should be possible to reduce Colorado potato beetle flight dispersal by selecting fields most exposed to wind over landscape-protected fields when rotating potato, Solanum tuberosum L., crops.

  9. Combined effects of Corexit EC 9500A with secondary abiotic and biotic factors in the rotifer Brachionus plicatilis.

    PubMed

    Williams, Michael B; Powell, Mickie L; Watts, Stephen A

    2016-10-01

    We examined lethality and behavioral effects of Corexit EC 9500A (C-9500A) exposure on the model marine zooplankton Brachionus plicatilis singularly and in combination with abiotic and biotic factors. C-9500A exposure at standard husbandry conditions (17.5ppt, 24°C, 200 rotifer*mL(-1) density) identified the 24h median lethal concentration, by Probit analysis, to be 107ppm for cultured B. plicatilis. Rotifers surviving exposure to higher concentrations (100 and 150ppm) exhibited a decreased swimming velocity and a reduced net to gross movement ratio. Significant interaction between C-9500A exposure and temperature or salinity was observed. Upper thermal range was reduced and maximal salinity stress was seen as ca. 25ppt. Increased or decreased nutritional availability over the exposure period did not significantly alter mortality of B. plicatilis populations at the concentrations tested. Results from this study may be useful for predicting possible outcomes on marine zooplankton following dispersant application under diverse natural conditions.

  10. [Variation characteristic in soil respiration of apple orchard and its biotic and abiotic influencing factors].

    PubMed

    Wang, Rui; Guo, Sheng-Li; Liu, Qing-Fang; Zhang, Yan-Jun; Jiang, Ji-Shao; Guo, Hui-Min; Li, Ru-Jian

    2014-05-01

    To evaluate the orchard variability of soil respiration and the response of soil respiration to its influencing factors is helpful for a deep understanding about the effects of converting cropland to apple orchard. A field experiment was conducted in the Changwu State Key Agro-Ecological Station. Soil respiration, soil temperature, soil moisture and roots biomasses were periodically measured in a mature apple orchard during 2011 and 2012. Soil respiration decreased as the distance from the trunk increased. The cumulative soil respiration in the 0.5 m-distance from the trunk was 20% and 31% higher than that in the 2 m-distance from the trunk, respectively in 2011 and 2012. The temperature sensitivity of soil respiration (Q10) was relatively lower in the 2 m-distance than that in the 0. 5 m-distance in both years. Soil temperature and soil moisture were slightly higher in the 2 m-distance, but there was no significant difference between the 2 m-distance and the 0. 5 m-distance. Soil respiration and soil temperature showed a significant exponential relationship, but there was no positive correlation between soil moisture and soil respiration. Soil temperature changes can explain seasonal variation of soil respiration well, but it could not explain its spatial variability. Root density was an important factor for the spatial variability of soil respiration and Q15. Variation of soil respiration coefficient was 23% -31%. Therefore, the distance from the trunk should be considered when estimating orchards soil respiration.

  11. Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland.

    PubMed

    He, Wei; Choi, Ilhwan; Lee, Jung-Joon; Hur, Jin

    2016-02-15

    In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-CL(-1), respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS+BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands.

  12. Influence of abiotic factors on cathemeral activity: the case of Eulemur fulvus collaris in the littoral forest of Madagascar.

    PubMed

    Donati, Giuseppe; Borgognini-Tarli, Silvana M

    2006-01-01

    The role environmental factors play in influencing circadian rhythms in natural habitats is still poorly described in primates, especially for those taxa with an activity cycle extended over the 24-hour cycle. In this paper, we elucidate the importance of abiotic factors in entraining the activity of cathemeral primates, focussing on results from a long-term study of Eulemur fulvus collaris (collared brown lemur) in south-eastern Malagasy littoral forest. Two groups of lemurs were followed for 60 whole-day and 59 whole-night observation periods over 14 months. Diurnal and nocturnal observations were equally distributed among moon phases and seasons. Temperature and humidity were recorded hourly by automatic data loggers. The littoral forest has a climatic environment where rainfall and humidity are uncorrelated with temperature and photoperiod. Diurnal and nocturnal activity varied seasonally, with the former increasing significantly with extended day length and the latter increasing significantly with shortened day length. Dusk seemed to act as a primary zeitgeber for these lemurs, coordinating the onset of evening activity throughout the entire year. Lunar phase and the nocturnal luminosity index correlated positively with the duration of nocturnal activity and negatively with the length of diurnal activity. Temperature was positively associated with diurnal activity but did not seem to influence lemur rhythms at night. Finally, lemur nocturnal activity significantly decreased when levels of humidity and rainfall were high. Cathemeral biorhythm is triggered by zeitgebers and influenced by masking factors. The activity of collared brown lemurs appears to be seasonally influenced by photoperiod and directly modulated by nocturnal ambient luminosity. These results are discussed by comparing data from other cathemeral species living in various climatic situations.

  13. Cork Oak Vulnerability to Fire: The Role of Bark Harvesting, Tree Characteristics and Abiotic Factors

    PubMed Central

    Catry, Filipe X.; Moreira, Francisco; Pausas, Juli G.; Fernandes, Paulo M.; Rego, Francisco; Cardillo, Enrique; Curt, Thomas

    2012-01-01

    Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently debarked individuals) and decreased with increasing bark thickness until cork was 3–4 cm thick. This bark thickness corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help estimating the impact of fire and to support management decisions. The results suggested that an appropriate management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak ecosystems. PMID:22787521

  14. Cork oak vulnerability to fire: the role of bark harvesting, tree characteristics and abiotic factors.

    PubMed

    Catry, Filipe X; Moreira, Francisco; Pausas, Juli G; Fernandes, Paulo M; Rego, Francisco; Cardillo, Enrique; Curt, Thomas

    2012-01-01

    Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently debarked individuals) and decreased with increasing bark thickness until cork was 3-4 cm thick. This bark thickness corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help estimating the impact of fire and to support management decisions. The results suggested that an appropriate management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak ecosystems.

  15. ENAC1, a NAC transcription factor, is an early and transient response regulator induced by abiotic stress in rice (Oryza sativa L.).

    PubMed

    Sun, Hui; Huang, Xi; Xu, Xingjun; Lan, Hongxia; Huang, Ji; Zhang, Hong-Sheng

    2012-10-01

    The plant-specific NAC (NAM, ATAF, and CUC)-domain proteins play important roles in plant development and stress responses. In this research, a full-length cDNA named ENAC1 (early NAC-domain protein induced by abiotic stress 1) was isolated from rice. ENAC1 possess one NAC domain in the N-terminus. Comparative time-course expression analysis indicated that ENAC1 expression, similar with OsDREB1A, was induced very quickly by various abiotic stresses including salt, drought, cold, and exogenous abscisic acid. However, the induction of ENAC1 by abiotic stress was transient and lasted up to 3 h, whereas that of OsDREB1A maintained longer. The promoter sequence of ENAC1 harbors several cis-elements including ABA response elements, but the well-known dehydration responsive element/C-repeat element is absent. The ENAC1-GFP (green fluorescent protein) fusion protein was localized in the nucleus of rice protoplast cell. Yeast hybrid assays revealed that ENAC1 was a transcription activator and bound to NAC recognition sequence (NACRS). Co-expression analysis suggested that ENAC1 co-expressed with a number of stress-related genes. Taken together, ENAC1 may be an early transcription activator of stress responses and function in the regulation of NACRS-mediated gene expression under abiotic stress.

  16. The impact of abiotic factors (temperature and glucose) on physicochemical properties of lipids from Yersinia pseudotuberculosis.

    PubMed

    Bakholdina, S I; Sanina, N M; Krasikova, I N; Popova, O B; Solov'eva, T F

    2004-12-01

    The impact of the availability of glucose in nutrition medium and growth temperature on the composition and thermotropic behavior of lipids from Yersinia pseudotuberculosis (Enterobacteriaceae) was studied. Y. pseudotuberculosis was grown in nutrition broth (NB) with/without glucose at 8 and 37 degrees C, corresponding to the temperatures of saprophytic and parasitic phases of this bacterium life. The decrease of phosphatidylethanolamine, phosphatidylglycerol and unsaturated fatty acids and the parallel increase of lysophosphatidylethanolamine and diphosphatidylglycerol and saturated and cyclopropane acids were the most significant changes with temperature in bacterial phospholipid (PL) classes and fatty acids, respectively. Glucose did not effect the direction of temperature-induced changes in the contents of PLs, fatty acids, however it enhanced (for PLs) or diminished (for fatty acids) intensity of these changes. The thermally induced transitions of lipids were studied by differential scanning calorimetry (DSC). It was revealed that the addition of glucose to NB induced a sharp shift of DSC thermograms to lower temperatures in the "warm" variants of bacteria. The peak maximum temperature (Tmax) of thermal transitions dropped from 50 to 26 degrees C that is the optimal growth temperature of Y. pseudotuberculosis. Tmax of total lipids of the cells grown at 8 degrees C without glucose in NB was equal to growth temperature that corresponded to the classical mechanism of homeoviscous adaptation of bacteria. An addition of glucose to NB at this growth temperature caused the subsequent reduction of Tmax to -8 degrees C, while the temperature ranges of thermograms were not substantially changed. So, not only the temperature growth of bacteria, but also the presence of glucose in NB can modify the physical state of lipids from Y. pseudotuberculosis. In this case, both factors affect additively. It is suggested that glucose influences some membrane-associated proteins and

  17. Effect of biotic and abiotic factors on in vitro proliferation, encystment, and excystment of Pfiesteria piscicida.

    PubMed

    Saito, Keiko; Drgon, Tomás; Krupatkina, Danara N; Drgonova, Jana; Terlizzi, Daniel E; Mercer, Natalia; Vasta, Gerardo R

    2007-10-01

    Pfiesteria spp. are mixotrophic armored dinoflagellates populating the Atlantic coastal waters of the United States. They have been a focus of intense research due to their reported association with several fish mortality events. We have now used a clonal culture of Pfiesteria piscicida and several new environmental isolates to describe growth characteristics, feeding, and factors contributing to the encystment and germination of the organism in both laboratory and environmental samples. We also discuss applied methods of detection of the different morphological forms of Pfiesteria in environmental samples. In summary, Pfiesteria, when grown with its algal prey, Rhodomonas sp., presents a typical growth curve with lag, exponential, and stationary phases, followed by encystment. The doubling time in exponential phase is about 12 h. The profiles of proliferation under a standard light cycle and in the dark were similar, although the peak cell densities were markedly lower when cells were grown in the dark. The addition of urea, chicken manure, and soil extracts did not enhance Pfiesteria proliferation, but crude unfiltered spent aquarium water did. Under conditions of food deprivation or cold (4 degrees C), Pfiesteria readily formed harvestable cysts that were further analyzed by PCR and scanning electron microscopy. The germination of Pfiesteria cysts in environmental sediment was enhanced by the presence of live fish: dinospores could be detected 13 to 15 days earlier and reached 5- to 10-times-higher peak cell densities with live fish than with artificial seawater or f/2 medium alone. The addition of ammonia, urea, nitrate, phosphate, or surprisingly, spent fish aquarium water had no effect.

  18. Ostreopsis cf. ovata dynamics in the NW Mediterranean Sea in relation to biotic and abiotic factors.

    PubMed

    Carnicer, Olga; Guallar, Carles; Andree, Karl B; Diogène, Jorge; Fernández-Tejedor, Margarita

    2015-11-01

    An expansion of the distribution of Ostreopsis cf. ovata, a dinoflagellate which produces palytoxin-like compounds, has been reported in recent years. Economical and social interests are affected by blooms, as they are responsible for respiratory and skin problems in humans and may cause damage to marine organisms. In order to identify the most influential environmental factors that trigger proliferations of O. cf. ovata in the area of the adjacent shallow rocky coast of the Ebro Delta (NW Mediterranean Sea) a three-year survey was performed on the metaphytic microalgae community growing on the macrophytes Jania rubens and Corallina elongata. Small-size diatoms were more abundant than dinoflagellates; O. cf. ovata was identified as the only species present from the genus. Seawater temperature was the primary driver defining the ecological niche of O. cf. ovata. Freshwater and groundwater fluxes were more pronounced in southern than in northern sites, which may have resulted in a distinct O. cf. ovata spatial distribution, with the highest records of abundance and more frequent blooms in the north. In consequence, negative correlations between the abundance of O. cf. ovata and nitrate concentrations and significant positive correlation with salinity were observed. The temporal pattern of O. cf. ovata dynamics from mid-July to early-November is probably due to the fact that this species is observed only above a certain threshold temperature of seawater. Metaphytic cells of O. cf. ovata were smaller in the northern site than in the south, possibly as a result of an increase in cell division, coinciding with higher abundance, and this could be an indicator of favorable conditions. Toxicity in planktonic cells was negatively correlated with cell abundance in the water column, achieving maximum concentrations of 25pg. PLTX eqcell(-1).

  19. Distribution and Diversity of Soil Microfauna from East Antarctica: Assessing the Link between Biotic and Abiotic Factors

    PubMed Central

    Velasco-Castrillón, Alejandro; Schultz, Mark B.; Colombo, Federica; Gibson, John A. E.; Davies, Kerrie A.; Austin, Andrew D.; Stevens, Mark I.

    2014-01-01

    Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw), with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw). Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3− and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity. PMID:24498126

  20. Distribution and diversity of soil microfauna from East Antarctica: assessing the link between biotic and abiotic factors.

    PubMed

    Velasco-Castrillón, Alejandro; Schultz, Mark B; Colombo, Federica; Gibson, John A E; Davies, Kerrie A; Austin, Andrew D; Stevens, Mark I

    2014-01-01

    Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw), with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw). Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3 (-) and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity.

  1. Abiotic and biotic factors affect efficacy of chlorfenapyr for control of stored-product insect pests.

    PubMed

    Kavallieratos, Nickolas G; Athanassiou, Christos G; Hatzikonstantinou, Ann N; Kavallieratou, Helen N

    2011-08-01

    Laboratory bioassays were conducted to assess pyrole chlorfenapyr as a potential grain protectant against adults of Rhyzopertha dominica, Sitophilus oryzae, Prostephanus truncatus, Tribolium confusum, and Liposcelis bostrychophila. Factors such as dose (0.01, 0.1, 0.5, 1, 5, and 10 ppm), exposure interval (7 and 14 days), temperature (20, 25, and 30°C), relative humidity (RH; 55 and 75%), and commodity (wheat, maize, barley, and paddy rice) were evaluated. Progeny production was assessed after 74 days of exposure. For L. bostrychophila and T. confusum the increase of dose increased mortality. After 7 or 14 days of exposure, mortality was low at doses of ≤ 1 ppm and did not exceed 23 or 36%, respectively, for L. bostrychophila or 13 or 58%, respectively, for T. confusum. After 14 days of exposure, mortality of S. oryzae at 30°C and 75% RH was 82.2%. Mortality of P. truncatus was considerably higher than that of the other species. At 0.5 ppm, mortality exceeded 81% after 7 days of exposure and 91% after 14 days of exposure. Progeny production of L. bostrychophila was extremely high. Very few progeny were found for T. confusum. For S. oryzae, offspring emergence was high, except at 20°C and 55% RH. For P. truncatus, progeny production in the treated maize was not avoided, even at 10 ppm. In the case of S. oryzae, at 0.1 ppm and after 14 days of exposure, mortality in wheat was higher than in the other three commodities. For R. dominica, mortality was low at 0.1 and 1 ppm for paddy rice but reached 74.4% in barley after 14 days of exposure. For T. confusum, mortality was low at 0.1 and 1 ppm in all commodities. For progeny production counts, for S. oryzae or R. dominica, adult emergence was higher in paddy rice than in the other three commodities. Finally, overall T. confusum progeny was low. Chlorfenapyr efficacy varied remarkably among the combinations tested, and it may be a viable grain protectant in combination with other insecticides.

  2. Effects of pH on the hydrolysis of lignocellulosic wastes and volatile fatty acids accumulation: the contribution of biotic and abiotic factors.

    PubMed

    Chen, Yi; Wen, Yue; Zhou, Junwei; Xu, Chao; Zhou, Qi

    2012-04-01

    In this study, a combination of micro-scale structure and extracellular enzyme activity (EEA) analysis was successfully used to explore the effect of pH (from 6.0 to 12.0) on wetland plant litter (WPL) hydrolysis and VFAs accumulation. During 30days of fermentation, the maximum VFAs production and abiotic release of carbohydrate, combined with the minimum EEAs were observed at pH 12.0, suggesting that abiotic factors were most important for hydrolysis and VFAs accumulation at pH 12.0. As the pH decreased, the factors most important to carbohydrate hydrolysis shifted from abiotic factors to biotic factors with the maximum bio-release of carbohydrate occurring at pH 9.0. Further investigation showed that pH 9.0 could significantly enhance the bio-release of carbohydrate through the increase in the mesoporous surface area, surface cellulose accessibility and cellulase activity. Alkaline fermentation at ambient temperature can be considered as a sustainable technology for VFAs recovery and WPL management.

  3. CkDREB gene in Caragana korshinskii is involved in the regulation of stress response to multiple abiotic stresses as an AP2/EREBP transcription factor.

    PubMed

    Wang, Xuemin; Chen, Xiaofang; Liu, Yun; Gao, Hongwen; Wang, Zan; Sun, Guizhi

    2011-04-01

    Using RACE method, a DREB-like gene-CkDREB, which contains a conserved AP2/ERF domain, was isolated from Caragana korshinskii. Full length of CkDREB cDNA was 1743 bp, including an ORF of 1038 bp and encoding a polypeptide of 345 amino acids. CkDREB protein shared high identification with other homologs from other plants. The KR-rich motif at the N-terminal region played an essential role in nuclear localization of CkDREB. Yeast one-hybrid experiments testified that CkDREB possess specific DRE element-binding activity and transcriptional activation. A variety of abiotic stress, including high salt, dehydration, low temperature all significantly induced the expression of CkDREB gene. Exogenous phytohormone ABA also slightly up-regulated the mRNA accumulation of CkDREB. Overexpression of CkDREB in transgenic tobacco plants resulted in enhanced tolerance to high salinity and osmotic stresses and induction of downstream target genes under normal conditions. These results suggested that CkDREB may play an essential role as a DREB transcription factor in regulation of stress-responsive signaling in C. korshinskii.

  4. Global analysis of WRKY transcription factor superfamily in Setaria identifies potential candidates involved in abiotic stress signaling

    PubMed Central

    Muthamilarasan, Mehanathan; Bonthala, Venkata S.; Khandelwal, Rohit; Jaishankar, Jananee; Shweta, Shweta; Nawaz, Kashif; Prasad, Manoj

    2015-01-01

    Transcription factors (TFs) are major players in stress signaling and constitute an integral part of signaling networks. Among the major TFs, WRKY proteins play pivotal roles in regulation of transcriptional reprogramming associated with stress responses. In view of this, genome- and transcriptome-wide identification of WRKY TF family was performed in the C4model plants, Setaria italica (SiWRKY) and S. viridis (SvWRKY), respectively. The study identified 105 SiWRKY and 44 SvWRKY proteins that were computationally analyzed for their physicochemical properties. Sequence alignment and phylogenetic analysis classified these proteins into three major groups, namely I, II, and III with majority of WRKY proteins belonging to group II (53 SiWRKY and 23 SvWRKY), followed by group III (39 SiWRKY and 11 SvWRKY) and group I (10 SiWRKY and 6 SvWRKY). Group II proteins were further classified into 5 subgroups (IIa to IIe) based on their phylogeny. Domain analysis showed the presence of WRKY motif and zinc finger-like structures in these proteins along with additional domains in a few proteins. All SiWRKY genes were physically mapped on the S. italica genome and their duplication analysis revealed that 10 and 8 gene pairs underwent tandem and segmental duplications, respectively. Comparative mapping of SiWRKY and SvWRKY genes in related C4 panicoid genomes demonstrated the orthologous relationships between these genomes. In silico expression analysis of SiWRKY and SvWRKY genes showed their differential expression patterns in different tissues and stress conditions. Expression profiling of candidate SiWRKY genes in response to stress (dehydration and salinity) and hormone treatments (abscisic acid, salicylic acid, and methyl jasmonate) suggested the putative involvement of SiWRKY066 and SiWRKY082 in stress and hormone signaling. These genes could be potential candidates for further characterization to delineate their functional roles in abiotic stress signaling. PMID:26635818

  5. Influence of plant ontogeny and abiotic factors on resistance of glandular-haired alfalfa to potato leafhopper (Hemiptera: Cicadellidae).

    PubMed

    Casteel, Clare L; Ranger, Christopher M; Backus, Elaine A; Ellersieck, Mark R; Johnson, David W

    2006-04-01

    Laboratory experiments were conducted to characterize the trichome-based defense of glandular-haired alfalfa, Medicago sativa L., against the potato leafhopper, Empoasca fabae (Harris). Within-plant variability in leafhopper resistance was examined by caging adult leafhoppers to either basal or apical stem internodes of the leafhopper-resistant, glandular-haired M. sativa genotype G98A or the susceptible, nonglandular-haired M. sativa 'Ranger'. Young, actively secreting glandular trichomes are located on apical internodes of G98A, whereas senesced gland heads are found on older, basal internodes of G98A. After 96 h, the highest cumulative leafhopper mortality and lowest number of excretory droplets were associated with apical internodes of G98A. No difference was detected in mortality and feeding levels among insects caged to basal internodes of G98A and basal and apical internodes of Ranger. The influence of abiotic factors on leafhopper resistance was evaluated by caging adult leafhoppers to either G98A or Ranger under four combinations of low and high light (250 and 1,000 micromol s(-1) m(-2)) and temperature regimes (17 and 30 degrees C). After 96 h, the highest cumulative mortality was associated with leafhoppers confined to G98A under high light and high temperature conditions. Temperature level and plant type also had an effect on the production of excretory droplets, resulting in the highest number of excretory droplets being associated with Ranger under the high temperature regime. These results indicate that certain regions of M. sativa G98A are better protected against the potato leafhopper than others and that temperature influences resistance levels of glandular-haired alfalfa.

  6. Habitat fragmentation as a result of biotic and abiotic factors controls pathogen transmission throughout a host population.

    PubMed

    Greer, Amy L; Collins, James P

    2008-03-01

    1. The hypothesis that habitat fragmentation (biotic or abiotic) alters the transmission of disease within a population is explored using field data from a well-studied amphibian-pathogen system. 2. We used the Ambystoma tigrinum-A. tigrinum virus (ATV) model system to show how habitat fragmentation as a result of emergent vegetation and habitat management affects disease transmission dynamics in ponds across a landscape. 3. We quantified variation in ATV infection over time and across the landscape. ATV infection was significantly higher in ponds modified for livestock use (P = 0.032). Disease incidence decreased with increased amounts of emergent vegetation (P < 0.001). These factors appear to control disease transmission by altering the host contact rate and with it disease transmission. 4. A field experiment to test the effect of emergent vegetation on the distribution of larvae in ponds demonstrated a behavioural change in larvae found in sparsely vegetated ponds. Microhabitat choices resulted in larvae being concentrated at the pond edge resulting in a 'halo effect' in sparsely vegetated ponds, whereas larvae in heavily vegetated ponds were distributed more evenly throughout. Microhabitat choice affects the effective density that larvae experience. This 'halo effect' increases contact rates in the shallows of sparsely vegetated ponds and increases the transmission of a directly transmitted pathogen. 5. Despite recurrent epidemics of a lethal Ranavirus in tiger salamanders on the Kaibab Plateau, Arizona, USA, these populations persist. We discuss the implications of our results in the context of density-dependent transmission and homogeneous mixing, two increases key assumptions of epidemiological theory.

  7. A seed preferential heat shock transcription factor from wheat provides abiotic stress tolerance and yield enhancement in transgenic Arabidopsis under heat stress environment.

    PubMed

    Chauhan, Harsh; Khurana, Neetika; Agarwal, Preeti; Khurana, Jitendra P; Khurana, Paramjit

    2013-01-01

    Reduction in crop yield and quality due to various abiotic stresses is a worldwide phenomenon. In the present investigation, a heat shock factor (HSF) gene expressing preferentially in developing seed tissues of wheat grown under high temperatures was cloned. This newly identified heat shock factor possesses the characteristic domains of class A type plant HSFs and shows high similarity to rice OsHsfA2d, hence named as TaHsfA2d. The transcription factor activity of TaHsfA2d was confirmed through transactivation assay in yeast. Transgenic Arabidopsis plants overexpressing TaHsfA2d not only possess higher tolerance towards high temperature but also showed considerable tolerance to salinity and drought stresses, they also showed higher yield and biomass accumulation under constant heat stress conditions. Analysis of putative target genes of AtHSFA2 through quantitative RT-PCR showed higher and constitutive expression of several abiotic stress responsive genes in transgenic Arabidopsis plants over-expressing TaHsfA2d. Under stress conditions, TaHsfA2d can also functionally complement the T-DNA insertion mutants of AtHsfA2, although partially. These observations suggest that TaHsfA2d may be useful in molecular breeding of crop plants, especially wheat, to improve yield under abiotic stress conditions.

  8. Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

    NASA Astrophysics Data System (ADS)

    Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C.

    2016-04-01

    High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

  9. Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

    PubMed Central

    Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C.

    2016-01-01

    High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments. PMID:27032533

  10. Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles.

    PubMed

    Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C

    2016-04-01

    High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

  11. Plant available silicon in South-east Asian rice paddy soils - relevance of agricultural practice and of abiotic factors

    NASA Astrophysics Data System (ADS)

    Marxen, A.; Klotzbücher, T.; Vetterlein, D.; Jahn, R.

    2012-12-01

    Background Silicon (Si) plays a crucial role in rice production. Si content of rice plants exceeds the content of other major nutrients such as nitrogen, phosphorous or potassium. Recent studies showed that in some environments external supply of Si can enhance the growth of rice plants. Rice plants express specific Si transporters to absorb Si from soil solutions in form of silicic acid, which precipitates in tissue cells forming amorphous silica bodies, called phytoliths. The phytoliths are returned to soils with plant residues. They might be a main source of plant available silicic acid in soils. Aims In this study we assess the effects of rice paddy cultivation on the stocks of `reactive` Si fractions in mineral topsoils of rice paddy fields in contrasting landscapes. The `reactive` Si fractions are presumed to determine the release of plant-available silicic acid in soils. We consider the relevance of abiotic factors (mineral assemblage; soil weathering status) and agricultural practice for these fractions. Agricultural practices, which were assumed to affect the stocks of `reactive` Si were (i) the usage of different rice varieties (which might differ in Si demand), (ii) straw residue management (i.e., whether straw residues are returned to the fields or removed and used e.g. as fodder), and (iii) yield level and number of crops per year. Material and methods Soils (top horizon of about 0-20 cm depth) were sampled from rice paddy fields in 2 mountainous and 5 lowland landscapes of contrasting geologic conditions in Vietnam and the Philippines. Ten paddy fields were sampled per landscape. The rice paddy management within landscapes differed when different farmers and/or communities managed the fields. We analysed the following fractions of `reactive` Si in the soils: acetate-extractable Si (dissolved and easily exchangeable Si), phosphate-extractable Si (adsorbed Si), oxalate extractable Si (Si associated with poorly-ordered sesquioxides), NaOH extractable Si

  12. The heat shock factor gene family in Salix suchowensis: a genome-wide survey and expression profiling during development and abiotic stresses

    PubMed Central

    Zhang, Jin; Li, Yu; Jia, Hui-Xia; Li, Jian-Bo; Huang, Juan; Lu, Meng-Zhu; Hu, Jian-Jun

    2015-01-01

    Heat shock transcription factors (Hsfs), which act as important transcriptional regulatory proteins, play crucial roles in plant developmental processes, and stress responses. Recently, the genome of the shrub willow Salix suchowensis was fully sequenced. In this study, a total of 27 non-redundant Hsf genes were identified from the S. suchowensis genome. Phylogenetic analysis revealed that the members of the SsuHsf family can be divided into three groups (class A, B, and C) based on their structural characteristics. Promoter analysis indicated that the SsuHsfs promoters included various cis-acting elements related to hormone and/or stress responses. Furthermore, the expression profiles of 27 SsuHsfs were analyzed in different tissues and under various stresses (heat, drought, salt, and ABA treatment) using RT-PCR. The results demonstrated that the SsuHsfs were involved in abiotic stress responses. Our results contribute to a better understanding of the complexity of the SsuHsf gene family, and will facilitate functional characterization in future studies. PMID:26442061

  13. Abiotic origin of biopolymers

    NASA Technical Reports Server (NTRS)

    Oro, J.; Stephen-Sherwood, E.

    1976-01-01

    A variety of methods have been investigated in different laboratories for the polymerization of amino acids and nucleotides under abiotic conditions. They include (1) thermal polymerization; (2) direct polymerization of certain amino acid nitriles, amides, or esters; (3) polymerization using polyphosphate esters; (4) polymerization under aqueous or drying conditions at moderate temperatures using a variety of simple catalysts or condensing agents like cyanamide, dicyandiamide, or imidazole; and (5) polymerization under similar mild conditions but employing activated monomers or abiotically synthesized high-energy compounds such as adenosine 5'-triphosphate (ATP). The role and significance of these methods for the synthesis of oligopeptides and oligonucleotides under possible primitive-earth conditions is evaluated. It is concluded that the more recent approach involving chemical processes similar to those used by contemporary living organisms appears to offer a reasonable solution to the prebiotic synthesis of these biopolymers.

  14. The NAC-type transcription factor OsNAC2 regulates ABA-dependent genes and abiotic stress tolerance in rice

    PubMed Central

    Shen, Jiabin; Lv, Bo; Luo, Liqiong; He, Jianmei; Mao, Chanjuan; Xi, Dandan; Ming, Feng

    2017-01-01

    Plants can perceive environmental changes and respond to external stressors. Here, we show that OsNAC2, a member of the NAC transcription factor family, was strongly induced by ABA and osmotic stressors such as drought and high salt. With reduced yields under drought conditions at the flowering stage, OsNAC2 overexpression lines had lower resistance to high salt and drought conditions. RNAi plants showed enhanced tolerance to high salinity and drought stress at both the vegetative and flowering stages. Furthermore, RNAi plants had improved yields after drought stress. A microarray assay indicated that many ABA-dependent stress-related genes were down-regulated in OsNAC2 overexpression lines. We further confirmed that OsNAC2 directly binds the promoters of LATE EMBRYOGENESIS ABUNDANT 3 (OsLEA3) and Stress-Activated Protein Kinases 1 (OsSAPK1), two marker genes in the abiotic stress and ABA response pathways, respectively. Our results suggest that in rice OsNAC2 regulates both abiotic stress responses and ABA-mediated responses, and acts at the junction between the ABA and abiotic stress pathways. PMID:28074873

  15. The Alfin-like homeodomain finger protein AL5 suppresses multiple negative factors to confer abiotic stress tolerance in Arabidopsis.

    PubMed

    Wei, Wei; Zhang, Yu-Qin; Tao, Jian-Jun; Chen, Hao-Wei; Li, Qing-Tian; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-03-01

    Plant homeodomain (PHD) finger proteins affect processes of growth and development by changing transcription and reading epigenetic histone modifications, but their functions in abiotic stress responses remain largely unclear. Here we characterized seven Arabidopsis thaliana Alfin1-like PHD finger proteins (ALs) in terms of the responses to abiotic stresses. ALs localized to the nucleus and repressed transcription. Except AL6, all the ALs bound to G-rich elements. Mutations of the amino acids at positions 34 and 35 in AL6 caused loss of ability to bind to G-rich elements. Expression of the AL genes responded differentially to osmotic stress, salt, cold and abscisic acid treatments. AL5-over-expressing plants showed higher tolerance to salt, drought and freezing stress than Col-0. Consistently, al5 mutants showed reduced stress tolerance. We used ChIP-Seq assays to identify eight direct targets of AL5, and found that AL5 binds to the promoter regions of these genes. Knockout mutants of five of these target genes exhibited varying tolerances to stresses. These results indicate that AL5 inhibits multiple signaling pathways to confer stress tolerance. Our study sheds light on mechanisms of AL5-mediated signaling in abiotic stress responses, and provides tools for improvement of stress tolerance in crop plants.

  16. Common and distinct functions of Arabidopsis class A1 and A2 heat shock factors in diverse abiotic stress responses and development.

    PubMed

    Liu, Hsiang-chin; Charng, Yee-yung

    2013-09-01

    There are 21 heat shock factor (HSF) homologs in Arabidopsis (Arabidopsis thaliana), of which members of class A1 (HSFA1a/HSFA1b/HSFA1d/HSFA1e) play the major role in activating the transcription of heat-induced genes, including HSFA2. Once induced, HSFA2 becomes the dominant HSF and is able to form heterooligomeric complexes with HSFA1. However, whether HSFA2 could function independently as a transcription regulator in the absence of the HSFA1s was undetermined. To address this question, we introduced a Cauliflower mosaic virus 35S promoter:HSFA2 construct into hsfa1a/hsfa1b/hsfa1d/hsfa1e quadruple knockout (QK) and wild-type (Wt) backgrounds to yield transgenic lines A2QK and A2Wt, respectively. Constitutive expression of HSFA2 rescued the developmental defects of the QK mutant and promoted callus formation in A2QK, but not in A2Wt, after heat treatment. Transcriptome analysis showed that heat stress response genes are differentially regulated by the HSFA1s and HSFA2; the genes involved in metabolism and redox homeostasis are preferentially regulated by HSFA2, while HSFA1-preferring genes are enriched in transcription function. Ectopic expression of HSFA2 complemented the defects of QK in tolerance to different heat stress regimes, and to hydrogen peroxide, but not to salt and osmotic stresses. Furthermore, we showed that HSFA1a/HSFA1b/HSFA1d are involved in thermotolerance to mild heat stress at temperatures as low as 27°C. We also noticed subfunctionalization of the four Arabidopsis A1-type HSFs in diverse abiotic stress responses. Overall, this study reveals the overlapping and distinct functions of class A1 and A2 HSFs and may enable more precise use of HSFs in engineering stress tolerance in the future.

  17. Review of recent transgenic studies on abiotic stress tolerance and future molecular breeding in potato

    PubMed Central

    Kikuchi, Akira; Huynh, Huu Duc; Endo, Tsukasa; Watanabe, Kazuo

    2015-01-01

    Global warming has become a major issue within the last decade. Traditional breeding programs for potato have focused on increasing productivity and quality and disease resistance, thus, modern cultivars have limited tolerance of abiotic stresses. The introgression of abiotic stress tolerance into modern cultivars is essential work for the future. Recently, many studies have investigated abiotic stress using transgenic techniques. This manuscript focuses on the study of abiotic stress, in particular drought, salinity and low temperature, during this century. Dividing studies into these three stress categories for this review was difficult. Thus, based on the study title and the transgene property, transgenic studies were classified into five categories in this review; oxidative scavengers, transcriptional factors, and above three abiotic categories. The review focuses on studies that investigate confer of stress tolerance and the identification of responsible factors, including wild relatives. From a practical application perspective, further evaluation of transgenic potato with abiotic stress tolerance is required. Although potato plants, including wild species, have a large potential for abiotic stress tolerance, exploration of the factors responsible for conferring this tolerance is still developing. Molecular breeding, including genetic engineering and conventional breeding using DNA markers, is expected to develop in the future. PMID:25931983

  18. Review of recent transgenic studies on abiotic stress tolerance and future molecular breeding in potato.

    PubMed

    Kikuchi, Akira; Huynh, Huu Duc; Endo, Tsukasa; Watanabe, Kazuo

    2015-03-01

    Global warming has become a major issue within the last decade. Traditional breeding programs for potato have focused on increasing productivity and quality and disease resistance, thus, modern cultivars have limited tolerance of abiotic stresses. The introgression of abiotic stress tolerance into modern cultivars is essential work for the future. Recently, many studies have investigated abiotic stress using transgenic techniques. This manuscript focuses on the study of abiotic stress, in particular drought, salinity and low temperature, during this century. Dividing studies into these three stress categories for this review was difficult. Thus, based on the study title and the transgene property, transgenic studies were classified into five categories in this review; oxidative scavengers, transcriptional factors, and above three abiotic categories. The review focuses on studies that investigate confer of stress tolerance and the identification of responsible factors, including wild relatives. From a practical application perspective, further evaluation of transgenic potato with abiotic stress tolerance is required. Although potato plants, including wild species, have a large potential for abiotic stress tolerance, exploration of the factors responsible for conferring this tolerance is still developing. Molecular breeding, including genetic engineering and conventional breeding using DNA markers, is expected to develop in the future.

  19. Four potato (Solanum tuberosum) ABCG transporters and their expression in response to abiotic factors and Phytophthora infestans infection.

    PubMed

    Ruocco, Michelina; Ambrosino, Patrizia; Lanzuise, Stefania; Woo, Sheridan Lois; Lorito, Matteo; Scala, Felice

    2011-12-15

    Pleiotropic drug resistant (PDR/ABCG) genes are involved in plant response to biotic and abiotic stresses. In this work, we cloned, from Solanum tuberosum, four PDR/ABCG transporter genes named StPDR1, StPDR2, StPDR3 and StPDR4, which were differentially expressed in plant tissues and cell cultures. A number of different chemically unrelated compounds were found to regulate the transcript levels of the four genes in cultured cells. In particular, StPDR2 was highly up-regulated in the presence of Botrytis cinerea cell walls, NaCl, 2,4-dichlorophenol, sclareol and α-solanin and biological compounds. The expression of the genes was also investigated by real time RT-PCR during infection by Phytophthora infestans. StPDR1 and StPDR2 were up-regulated about 13- and 37-fold at 48 h post-infection (hpi), StPDR3 was expressed (4-5-fold) at 24 and 48 hpi and then rapidly decreased, while StPDR4 RNA accumulation was stimulated (about 4-fold) at 12 and 24 hpi, decreased at 48 hpi and increased again at 96 hpi. We discuss the role of StPDR1-4 genes in response to pathogens and abiotic stresses.

  20. Characterization of tomato Cycling Dof Factors reveals conserved and new functions in the control of flowering time and abiotic stress responses.

    PubMed

    Corrales, Alba-Rocío; Nebauer, Sergio G; Carrillo, Laura; Fernández-Nohales, Pedro; Marqués, Jorge; Renau-Morata, Begoña; Granell, Antonio; Pollmann, Stephan; Vicente-Carbajosa, Jesús; Molina, Rosa-Victoria; Medina, Joaquín

    2014-03-01

    DNA binding with One Finger (DOF) transcription factors are involved in multiple aspects of plant growth and development but their precise roles in abiotic stress tolerance are largely unknown. Here we report a group of five tomato DOF genes, homologous to Arabidopsis Cycling DOF Factors (CDFs), that function as transcriptional regulators involved in responses to drought and salt stress and flowering-time control in a gene-specific manner. SlCDF1-5 are nuclear proteins that display specific binding with different affinities to canonical DNA target sequences and present diverse transcriptional activation capacities in vivo. SlCDF1-5 genes exhibited distinct diurnal expression patterns and were differentially induced in response to osmotic, salt, heat, and low-temperature stresses. Arabidopsis plants overexpressing SlCDF1 or SlCDF3 showed increased drought and salt tolerance. In addition, the expression of various stress-responsive genes, such as COR15, RD29A, and RD10, were differentially activated in the overexpressing lines. Interestingly, overexpression in Arabidopsis of SlCDF3 but not SlCDF1 promotes late flowering through modulation of the expression of flowering control genes such as CO and FT. Overall, our data connect SlCDFs to undescribed functions related to abiotic stress tolerance and flowering time through the regulation of specific target genes and an increase in particular metabolites.

  1. Individual Cell Based Traits Obtained by Scanning Flow-Cytometry Show Selection by Biotic and Abiotic Environmental Factors during a Phytoplankton Spring Bloom

    PubMed Central

    Pomati, Francesco; Kraft, Nathan J. B.; Posch, Thomas; Eugster, Bettina; Jokela, Jukka; Ibelings, Bas W.

    2013-01-01

    In ecology and evolution, the primary challenge in understanding the processes that shape biodiversity is to assess the relationship between the phenotypic traits of organisms and the environment. Here we tested for selection on physio-morphological traits measured by scanning flow-cytometry at the individual level in phytoplankton communities under a temporally changing biotic and abiotic environment. Our aim was to study how high-frequency temporal changes in the environment influence biodiversity dynamics in a natural community. We focused on a spring bloom in Lake Zurich (Switzerland), characterized by rapid changes in phytoplankton, water conditions, nutrients and grazing (mainly mediated by herbivore ciliates). We described bloom dynamics in terms of taxonomic and trait-based diversity and found that diversity dynamics of trait-based groups were more pronounced than those of identified phytoplankton taxa. We characterized the linkage between measured phytoplankton traits, abiotic environmental factors and abundance of the main grazers and observed weak but significant correlations between changing abiotic and biotic conditions and measured size-related and fluorescence-related traits. We tested for deviations in observed community-wide distributions of focal traits from random patterns and found evidence for both clustering and even spacing of traits, occurring sporadically over the time series. Patterns were consistent with environmental filtering and phenotypic divergence under herbivore pressure, respectively. Size-related traits showed significant even spacing during the peak of herbivore abundance, suggesting that morphology-related traits were under selection from grazing. Pigment distribution within cells and colonies appeared instead to be associated with acclimation to temperature and water chemistry. We found support for trade-offs among grazing resistance and environmental tolerance traits, as well as for substantial periods of dynamics in which

  2. Abiotic and biotic factors associated with tick population dynamics on a mammalian host: Ixodes hexagonus infesting otters, Lutra lutra.

    PubMed

    Sherrard-Smith, Ellie; Chadwick, Elizabeth; Cable, Joanne

    2012-01-01

    The Eurasian otter, Lutra lutra, hosts several parasites with zoonotic potential. As this semiaquatic mammal has large ranges across terrestrial, freshwater and marine habitats, it has the capacity for wide dispersion of pathogens. Despite this, parasites of otters have received relatively little attention. Here, we examine their ectoparasite load and assess whether this is influenced by abiotic or biotic variables. Climatic phenomena such as the North Atlantic Oscillation (NAO) affect weather conditions in northern Europe. Consequently parasite distributions, particularly species with life stages exposed to the external environment, can be affected. We assessed the extent to which inter-annual variations in large-scale weather patterns (specifically the NAO and Central England (CE) temperatures) and host characteristics influenced tick prevalence and intensity. Ectoparasites consisted of a single species, the nidiculous tick Ixodes hexagonus (prevalence = 24.3%; mean intensity = 7.2; range = 1-122; on n = 820 otter hosts). The prevalence, but not intensity of infestation, was associated with high CE temperatures, while both prevalence and intensity were associated with positive phases of the NAO. Such associations indicate that I. hexagonus are most abundant when weather conditions are warmer and wetter. Ticks were more prevalent on juvenile than sub-adult or adult otters, which probably reflects the length of time the hosts spend in the holt where these ticks quest. High tick number was associated with poor host condition, so either poor condition hosts are more susceptible to ticks, or tick infestations negatively impact on host condition. Otters are clearly an important and common host for I. hexagonus, which has implications for vector-borne diseases. This work is the first to consider the impacts of long-term weather patterns on I. hexagonus and uses wild-animal cadavers to illustrate the importance of abiotic and biotic pressures impacting parasitic

  3. PsAP2 an AP2/ERF family transcription factor from Papaver somniferum enhances abiotic and biotic stress tolerance in transgenic tobacco.

    PubMed

    Mishra, Sonal; Phukan, Ujjal J; Tripathi, Vineeta; Singh, Dhananjay K; Luqman, Suaib; Shukla, Rakesh Kumar

    2015-09-01

    The AP2/ERFs are one of the most important family of transcription factors which regulate multiple responses like stress, metabolism and development in plants. We isolated PsAP2 a novel AP2/ERF from Papaver somniferum which was highly upregulated in response to wounding followed by ethylene, methyl jasmonate and ABA treatment. PsAP2 showed specific binding with both DRE and GCC box elements and it was able to transactivate the reporter genes in yeast. PsAP2 overexpressing transgenic tobacco plants exhibited enhanced tolerance towards both abiotic and biotic stresses . Real time transcript expression analysis showed constitutive upregulation of tobacco Alternative oxidase1a and Myo-inositol-1-phosphate synthase in PsAP2 overexpressing tobacco plants. Further, PsAP2 showed interaction with NtAOX1a promoter in vitro, it also specifically activated the NtAOX1a promoter in yeast and tobacco BY2 cells. The silencing of PsAP2 using VIGS lead to significant reduction in the AOX1 level in P. somniferum. Taken together PsAP2 can directly bind and transcriptionally activate NtAOX1a and its overexpression in tobacco imparted increased tolerance towards both abiotic and biotic stress.

  4. Genome-wide identification and characterization of the Populus WRKY transcription factor family and analysis of their expression in response to biotic and abiotic stresses.

    PubMed

    Jiang, Yuanzhong; Duan, Yanjiao; Yin, Jia; Ye, Shenglong; Zhu, Jingru; Zhang, Faqi; Lu, Wanxiang; Fan, Di; Luo, Keming

    2014-12-01

    WRKY proteins are a large family of regulators involved in various developmental and physiological processes, especially in coping with diverse biotic and abiotic stresses. In this study, 100 putative PtrWRKY genes encoded the proteins contained in the complete WRKY domain in Populus. Phylogenetic analysis revealed that the members of this superfamily among poplar, Arabidopsis, and other species were divided into three groups with several subgroups based on the structures of the WRKY protein sequences. Various cis-acting elements related to stress and defence responses were found in the promoter regions of PtrWRKY genes by promoter analysis. High-throughput transcriptomic analyses identified that 61 of the PtrWRKY genes were induced by biotic and abiotic treatments, such as Marssonina brunnea, salicylic acid (SA), methyl jasmonate (MeJA), wounding, cold, and salinity. Among these PtrWRKY genes, transcripts of 46 selected genes were observed in different tissues, including roots, stems, and leaves. Quantitative RT-PCR analysis further confirmed the induced expression of 18 PtrWRKY genes by one or more stress treatments. The overexpression of an SA-inducible gene, PtrWRKY89, accelerated expression of PR protein genes and improved resistance to pathogens in transgenic poplar, suggesting that PtrWRKY89 is a regulator of an SA-dependent defence-signalling pathway in poplar. Taken together, our results provided significant information for improving the resistance and stress tolerance of woody plants.

  5. The transcription factor SlAREB1 confers drought, salt stress tolerance and regulates biotic and abiotic stress-related genes in tomato.

    PubMed

    Orellana, Sandra; Yañez, Mónica; Espinoza, Analía; Verdugo, Isabel; González, Enrique; Ruiz-Lara, Simón; Casaretto, José A

    2010-12-01

    Members of the abscisic acid-responsive element binding protein (AREB)/abscisic acid-responsive element binding factor (ABF) subfamily of basic leucine zipper (bZIP) transcription factors have been implicated in abscisic acid (ABA) and abiotic stress responses in plants. Here we describe two members identified in cultivated tomato (Solanum lycopersicum), named SlAREB1 and SlAREB2. Expression of SlAREB1 and SlAREB2 is induced by drought and salinity in both leaves and root tissues, although that of SlAREB1 was more affected. In stress assays, SlAREB1-overexpressing transgenic tomato plants showed increased tolerance to salt and water stress compared to wild-type and SlAREB1-down-regulating transgenic plants, as assessed by physiological parameters such as relative water content (RWC), chlorophyll fluorescence and damage by lipoperoxidation. In order to identify SlAREB1 target genes responsible for the enhanced tolerance, microarray and cDNA-amplified fragment length polymorphism (AFLP) analyses were performed. Genes encoding oxidative stress-related proteins, lipid transfer proteins (LTPs), transcription regulators and late embryogenesis abundant proteins were found among the up-regulated genes in SlAREB1-overexpressing lines, especially in aerial tissue. Notably, several genes encoding defence proteins associated with responses to biotic stress (e.g. pathogenesis-related proteins, protease inhibitors, and catabolic enzymes) were also up-regulated by SlAREB1 overexpression, suggesting that this bZIP transcription factor is involved in ABA signals that participate in abiotic stress and possibly in response to pathogens.

  6. Using vegetation model-to-data comparisons to test the role of abiotic factors in the Neogene and Quaternary origins of modern C4 grasslands

    NASA Astrophysics Data System (ADS)

    Fox, D. L.; Strömberg, C.; Pau, S.; Taylor, L.; Lehmann, C.; Osborne, C.; Beerling, D. J.; Still, C. J.

    2014-12-01

    ) of multiple plant functional types (C3 and C4 grasses, evergreen and deciduous trees). Statistical comparisons of the isotopic and paleobotanical databases with the paleoclimate and vegetation model outputs allows us to assess the possible role of abiotic factors in the evolution of modern C4 grasslands during the late Neogene.

  7. Recovery of white sturgeon populations through natural production: Understanding the influence of abiotic and biotic factors on spawning and subsequent recruitment

    USGS Publications Warehouse

    Parsley, M.J.; Anders, P.J.; Miller, A.I.; Beckman, L.G.; McCabe, G.T.

    2002-01-01

    Recovery or maintenance of sturgeon populations through natural production in perturbed rivers requires adequate knowledge of the abiotic and biotic factors that influence spawning and cause mortality of embryonic, larval, and juvenile life stages. Although it is known that year-class strength of white sturgeon Acipenser transmontanus is determined within 2-3 months after spawning, little is known about specific causes of mortality to early life stages during this period. Initial spawning success is critical in the development of a strong year-class, and maximized recruitment may be dependent upon water temperature and the availability of optimal in-river habitat. Analyses have shown that increased river discharge combined with suitable water temperatures during spawning, egg incubation, yolk sac larvae dispersal, and first exogenous feeding result in greater recruitment. However, little is known about the importance of other variables, such as food availability or losses due to predation that influence year-class strength. ?? 2002 by the American Fisheries Society.

  8. Biotic and abiotic factors influencing the long-term stability of covers on waste rock piles in the uranium mining district of Saxony and Thuringia (Germany)

    SciTech Connect

    Heinze, M.; Koehler, M.; Saenger, H.

    1999-07-01

    This report presents the results of basic investigations of root penetration on various partially covered excavation discard material mounds of the Saxonian-Thuringian uranium mining region (Germany) in comparison to root penetration in autochthonous (native) soils. Bioturbation is an essential, unavoidable impact to consider in addition to root penetration. With increasing age, the functionality of each layer of a cover system becomes diminished through the workings of the local flora and fauna. Pedological cover layers can only temporarily maintain their initial positions and technical functionality. Considering actual prevailing biotic and abiotic influences (e.g., site-specific transpiration rates), the planning and installation of cover systems should take into account (within acceptable balances) factors which are able to at least partially compensate for eventual diminishing of technical functionality.

  9. Effects of biotic and abiotic factors on grape root borer (Lepidoptera: Sesiidae) infestations in commercial vineyards in Virginia.

    PubMed

    Rijal, Jhalendra P; Brewster, C C; Bergh, J C

    2014-10-01

    Larval grape root borer, Vitacea polistiformis (Harris) (Lepidoptera: Sesiidae), feed on roots of wild Vitis and commercially important Vitis species and rootstocks in portions of the eastern United States. Grape root borer pupal exuviae sampling in Virginia vineyards from 2008 to 2012 revealed that infestation levels varied substantially among 48 vineyard blocks. Data on horticultural (cultivar, rootstock, vine age, and planting area), cultural (insecticide use, ground cover, weed control, and irrigation), and environmental variables (proximity to forest, soil composition, soil moisture holding capacity, pH, organic matter, bulk density, and cation exchange capacity) from each block were subjected to optimal quantification using categorical principal component analysis (CATPCA). Variables with component loading values ≥0.70 from the CATPCA were used as predictors and pupal exuviae density as the dependent variable in binary logistic regression. A prediction model was developed by including statistically significant variables in the logistic regression. CATPCA showed that seven vineyard factors (ground cover, soil texture, soil mass moisture, soil pH, clay/sand ratio, clay/silt ratio, and sand/silt ratio) based on three selected principal components were significant for subsequent regression analysis. Binary logistic regression showed that soil mass moisture and clay/sand ratio were statistically significant factors contributing to differences in infestation among vineyard blocks. Based on these two factors, a risk prediction model for calculating the probability of grape root borer infestation in vineyards was developed and validated using receiver operating characteristic curve. Results are discussed in relation to the practical implications of a predictive, risk assessment model for grape root borer management.

  10. Biotic and abiotic factors related to rainbow smelt recruitment in the Wisconsin waters of Lake Superior, 1978-1997

    USGS Publications Warehouse

    Hoff, Michael H.

    2004-01-01

    Lake Superior rainbow smelt (Osmerus mordax) recruitment to 12-13 months of age in the Wisconsin waters of Lake Superior varied by a factor of 9.3 during 1978-1997. Management agencies have sought models that accurately predict recruitment, but no satisfactory models had previously been developed. In this study, modeling was conducted to determine which factors best explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data accounted for 63% of the variability in recruitment data. The functional relationship that accounted for the greatest amount of recruitment variation (81%) included rainbow smelt stock size, May rainfall, and bloater (Coregonus hoyi) biomass. Model results were interpreted to mean that recruitment was affected negatively by increased river flows from increased rainfall, and affected positively by the biomass of bloater, and those results were interpreted to mean that bloater mediated the effects of lake trout predation on rainbow smelt recruits. Model results were also interpreted to mean that stock size caused compensatory, density-dependent mortality on rainbow smelt recruits. Correlations observed here may be of value to managers seeking approaches to either enhance or control populations of this species, which is not indigenous to the Great Lakes.

  11. Toward understanding transcriptional regulatory networks in abiotic stress responses and tolerance in rice

    PubMed Central

    2012-01-01

    Abiotic stress causes loss of crop production. Under abiotic stress conditions, expression of many genes is induced, and their products have important roles in stress responses and tolerance. Progress has been made in understanding the biological roles of regulons in abiotic stress responses in rice. A number of transcription factors (TFs) regulate stress-responsive gene expression. OsDREB1s and OsDREB2s were identified as abiotic-stress responsive TFs that belong to the AP2/ERF family. Similar to Arabidopsis, these DREB regulons were most likely not involved in the abscisic acid (ABA) pathway. OsAREBs such as OsAREB1 were identified as key components in ABA-dependent transcriptional networks in rice. OsNAC/SNACs including OsNAC6 were characterized as factors that regulate expression of genes important for abiotic stress responses in rice. Here, we review on the rice abiotic-stress responses mediated by transcriptional networks, with the main focus on TFs that function in abiotic stress responses and confer stress tolerance in rice. PMID:24764506

  12. Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata.

    PubMed

    Agrahari, P; Singh, D K

    2013-11-01

    Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September.

  13. The CarERF genes in chickpea (Cicer arietinum L.) and the identification of CarERF116 as abiotic stress responsive transcription factor.

    PubMed

    Deokar, Amit A; Kondawar, Vishwajith; Kohli, Deshika; Aslam, Mohammad; Jain, Pradeep K; Karuppayil, S Mohan; Varshney, Rajeev K; Srinivasan, Ramamurthy

    2015-01-01

    The AP2/ERF family is one of the largest transcription factor gene families that are involved in various plant processes, especially in response to biotic and abiotic stresses. Complete genome sequences of one of the world's most important pulse crops chickpea (Cicer arietinum L.), has provided an important opportunity to identify and characterize genome-wide ERF genes. In this study, we identified 120 putative ERF genes from chickpea. The genomic organization of the chickpea ERF genes suggested that the gene family might have been expanded through the segmental duplications. The 120 member ERF family was classified into eleven distinct groups (I-X and VI-L). Transcriptional factor CarERF116, which is differentially expressed between drought tolerant and susceptible chickpea cultivar under terminal drought stress has been identified and functionally characterized. The CarERF116 encodes a putative protein of 241 amino acids and classified into group IX of ERF family. An in vitro CarERF116 protein-DNA binding assay demonstrated that CarERF116 protein specifically interacts with GCC box. We demonstrate that CarERF116 is capable of transactivation activity of and show that the functional transcriptional domain lies at the C-terminal region of the CarERF116. In transgenic Arabidopsis plants overexpressing CarERF116, significant up-regulation of several stress related genes were observed. These plants also exhibit resistance to osmotic stress and reduced sensitivity to ABA during seed germination. Based on these findings, we conclude that CarERF116 is an abiotic stress responsive gene, which plays an important role in stress tolerance. In addition, the present study leads to genome-wide identification and evolutionary analyses of chickpea ERF gene family, which will facilitate further research on this important group of genes and provides valuable resources for comparative genomics among the grain legumes.

  14. The auxin response factor gene family in banana: genome-wide identification and expression analyses during development, ripening, and abiotic stress

    PubMed Central

    Hu, Wei; Zuo, Jiao; Hou, Xiaowan; Yan, Yan; Wei, Yunxie; Liu, Juhua; Li, Meiying; Xu, Biyu; Jin, Zhiqiang

    2015-01-01

    Auxin signaling regulates various auxin-responsive genes via two types of transcriptional regulators, Auxin Response Factors (ARF) and Aux/IAA. ARF transcription factors act as critical components of auxin signaling that play important roles in modulating various biological processes. However, limited information about this gene family in fruit crops is currently available. Herein, 47 ARF genes were identified in banana based on its genome sequence. Phylogenetic analysis of the ARFs from banana, rice, and Arabidopsis suggested that the ARFs could be divided into four subgroups, among which most ARFs from the banana showed a closer relationship with those from rice than those from Arabidopsis. Conserved motif analysis showed that all identified MaARFs had typical DNA-binding and ARF domains, but 12 members lacked the dimerization domain. Gene structure analysis showed that the number of exons in MaARF genes ranged from 5 to 21, suggesting large variation amongst banana ARF genes. The comprehensive expression profiles of MaARF genes yielded useful information about their involvement in diverse tissues, different stages of fruit development and ripening, and responses to abiotic stresses in different varieties. Interaction networks and co-expression assays indicated the strong transcriptional response of banana ARFs and ARF-mediated networks in early fruit development for different varieties. Our systematic analysis of MaARFs revealed robust tissue-specific, development-dependent, and abiotic stress-responsive candidate MaARF genes for further functional assays in planta. These findings could lead to potential applications in the genetic improvement of banana cultivars, and yield new insights into the complexity of the control of MaARF gene expression at the transcriptional level. Finally, they support the hypothesis that ARFs are a crucial component of the auxin signaling pathway, which regulates a wide range of physiological processes. PMID:26442055

  15. Biotic and abiotic factors investigated in two Drosophila species – evidence of both negative and positive effects of interactions on performance

    PubMed Central

    Ørsted, Michael; Schou, Mads Fristrup; Kristensen, Torsten Nygaard

    2017-01-01

    Multiple environmental factors acting in concert can interact and strongly influence population fitness and ecosystem composition. Studies investigating interactions usually involve only two environmental factors; most frequently a chemical and another abiotic factor such as a stressful temperature. Here we investigate the effects of three environmental factors: temperature, an insecticide (dimethoate) and interspecific co-occurrence. We expose two naturally co-occurring species of Drosophila (D. hydei and D. melanogaster) to the different environments during development and examine the consequences on several performance measures. Results are highly species and trait specific with evidence of two- and three-way interactions in approximately 30% of all cases, suggesting that additive effects of combined environmental factors are most common, and that interactions are not universal. To provide more informative descriptions of complex interactions we implemented re-conceptualised definitions of synergism and antagonism. We found approximately equal proportions of synergistic and antagonistic interactions in both species, however the effects of interactions on performance differed between the two. Furthermore, we found negative impacts on performance in only 60% of interactions, thus our study also reveals a high proportion of cases with positive effects of interactions. PMID:28059144

  16. Biotic and abiotic factors related to lake herring recruitment in the Wisconsin waters of Lake Superior, 1984-1998

    USGS Publications Warehouse

    Hoff, Michael H.

    2004-01-01

    Lake Superior lake herring (Coregonus artedi) recruitment to 13-14 months of age in the Wisconsin waters of Lake Superior varied by a factor of 5,233 during 1984-1998. Management agencies have sought models that accurately predict recruitment, but no satisfactory model had previously been developed. Lake herring recruitment was modeled to determine which factors most explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data explained 35% of the variability in the recruitment data. The functional relationship that explained the greatest amount of recruitment variation (93%) included lake herring stock size, lake trout (Salvelinus namaycush) population size, slimy sculpin (Cottus cognatus) biomass, the interaction of mean daily wind speed in April (month of hatch) and lake herring stock size, and mean air temperature in April (when lake herring are 12-months old). Model results were interpreted to mean that lake herring recruitment was affected negatively by: slimy sculpin predation on lake herring ova; predation on age-0 lake herring by lake trout; and adult cannibalism on lake herring larvae, which was reduced by increased wind speed. April temperature was the variable that explained the least amount of variability in recruitment, but lake herring recruitment was positively affected by a warm April, which shortened winter and apparently reduced first-winter mortality. Stock size caused compensatory, density-dependent mortality on lake herring recruits. Management efforts appear best targeted at stock size protection, and empirical data implies that stock size in the Wisconsin waters of the lake should be maintained at 2.1-15.0 adults/ha in spring, bottom-trawl surveys.

  17. Spatial patterns of distribution and the influence of seasonal and abiotic factors on demersal ichthyofauna in an estuarine tropical bay.

    PubMed

    da Silva, D R; Paranhos, R; Vianna, M

    2016-07-01

    This study focused on the influence of local-scale environmental factors on key metrics of fish community structure and function at Guanabara Bay, an estuarine system that differs from all other south-western Atlantic estuaries due to the influence of an annual low-intensity upwelling event during late spring and summer, between November and March, when a warm rainy climate prevails. The spatial patterns of the bottom temperature and salinity were more heterogeneous during the rainy season than the dry season, being linked to total precipitation and seasonal oceanographic events. The study identified 130 species and 45 families, placing Guanabara Bay as one of the most species-rich tropical estuarine ecosystems, far exceeding 22 other Brazilian estuaries. These results, in addition to characteristics such as a relatively well-preserved mangrove forest, high productivity and favourable conditions for the growth and reproduction of estuarine species, indicate that Guanabara Bay plays a central role in supporting large populations of fishes, including commercially important species.

  18. Genome-wide analysis of AP2/ERF transcription factors in carrot (Daucus carota L.) reveals evolution and expression profiles under abiotic stress.

    PubMed

    Li, Meng-Yao; Xu, Zhi-Sheng; Huang, Ying; Tian, Chang; Wang, Feng; Xiong, Ai-Sheng

    2015-12-01

    AP2/ERF is a large transcription factor family that regulates plant physiological processes, such as plant development and stress response. Carrot (Daucus carota L.) is an important economical crop with a genome size of 480 Mb; the draft genome sequencing of this crop has been completed by our group. However, little is known about the AP2/ERF factors in carrot. In this study, a total of 267 putative AP2/ERF factors were identified from the whole-genome sequence of carrot. These AP2/ERF proteins were phylogenetically clustered into five subfamilies based on their similarity to the amino acid sequences from Arabidopsis. The distribution and comparative genome analysis of the AP2/ERF factors among plants showed the AP2/ERF factors had expansion during the evolutionary process, and the AP2 domain was highly conserved during evolution. The number of AP2/ERF factors in land plants expanded during their evolution. A total of 60 orthologous and 145 coorthologous AP2/ERF gene pairs between carrot and Arabidopsis were identified, and the interaction network of orthologous genes was constructed. The expression patterns of eight AP2/ERF family genes from each subfamily (DREB, ERF, AP2, and RAV) were related to abiotic stresses. Yeast one-hybrid and β-galactosidase activity assays confirmed the DRE and GCC box-binding activities of DREB subfamily genes. This study is the first to identify and characterize the AP2/ERF transcription factors in carrot using whole-genome analysis, and the findings may serve as references for future functional research on the transcription factors in carrot.

  19. Use of a generalized additive model to investigate key abiotic factors affecting microcystin cellular quotas in heavy bloom areas of Lake Taihu.

    PubMed

    Tao, Min; Xie, Ping; Chen, Jun; Qin, Boqiang; Zhang, Dawen; Niu, Yuan; Zhang, Meng; Wang, Qing; Wu, Laiyan

    2012-01-01

    Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation.

  20. Temporal dynamics of abiotic and biotic factors on leaf litter of three plant species in relation to decomposition rate along a subalpine elevation gradient.

    PubMed

    Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

    2013-01-01

    Relationships between abiotic (soil temperature and number of freeze-thaw cycles) or biotic factors (chemical elements, microbial biomass, extracellular enzymes, and decomposer communities in litter) and litter decomposition rates were investigated over two years in subalpine forests close to the Qinghai-Tibet Plateau in China. Litterbags with senescent birch, fir, and spruce leaves were placed on the forest floor at 2,704 m, 3,023 m, 3,298 m, and 3,582 m elevation. Results showed that the decomposition rate positively correlated with soil mean temperature during the plant growing season, and with the number of soil freeze-thaw cycles during the winter. Concentrations of soluble nitrogen (N), phosphorus (P) and potassium (K) had positive effects but C:N and lignin:N ratios had negative effects on the decomposition rate (k), especially during the winter. Meanwhile, microbial biomass carbon (MBC), N (MBN), and P (MBP) were positively correlated with k values during the first growing season. These biotic factors accounted for 60.0% and 56.4% of the variation in decomposition rate during the winter and the growing season in the first year, respectively. Specifically, litter chemistry (C, N, P, K, lignin, C:N and lignin:N ratio) independently explained 29.6% and 13.3%, and the microbe-related factors (MBC, MBN, MBP, bacterial and fungal biomass, sucrase and ACP activity) explained 22.9% and 34.9% during the first winter and the first growing season, respectively. We conclude that frequent freeze-thaw cycles and litter chemical properties determine the winter decomposition while microbe-related factors play more important roles in determining decomposition in the subsequent growing season.

  1. A novel ethylene-responsive factor from Tamarix hispida, ThERF1, is a GCC-box- and DRE-motif binding protein that negatively modulates abiotic stress tolerance in Arabidopsis.

    PubMed

    Wang, Liuqiang; Qin, Liping; Liu, Wenjin; Zhang, Daoyuan; Wang, Yucheng

    2014-09-01

    Ethylene-responsive factor (ERF) family is one of the largest families of plant-specific transcription factor that can positively or negatively regulate abiotic stress tolerance. However, their functions in regulating abiotic stress tolerance are still not fully understood. In this study, we characterized the functions of an ERF gene from Tamarix hispida, ThERF1, which can negatively regulate abiotic stress tolerance. The expression of ThERF1 was induced by salinity, PEG-simulated drought and abscisic acid (ABA) treatments. ThERF1 can specifically bind to GCC-box and DRE motifs. Overexpression of ThERF1 in transgenic Arabidopsis plants showed inhibited seed germination, and decreased fresh weight gain and root growth compared with wild-type (WT) plants. In addition, the transcript levels of several superoxide dismutase (SOD) and peroxidase (POD) genes in transgenic plants were significantly inhibited compared with in WT plants, resulting in decreased SOD and POD activities in transgenic plants under salt and drought stress conditions. Furthermore, the reactive oxygen species (ROS) levels, malondialdehyde (MDA) contents and cell membrane damage in ThERF1-transformed plants were all highly increased relative to WT plants. Our results suggest that ThERF1 negatively regulates abiotic stress tolerance by strongly inhibiting the expression of SOD and POD genes, leading to decreased ROS-scavenging ability.

  2. No Silver Bullet – Canonical Poly(ADP-Ribose) Polymerases (PARPs) Are No Universal Factors of Abiotic and Biotic Stress Resistance of Arabidopsis thaliana

    PubMed Central

    Rissel, Dagmar; Heym, Peter P.; Thor, Kathrin; Brandt, Wolfgang; Wessjohann, Ludger A.; Peiter, Edgar

    2017-01-01

    Abiotic and biotic stress can have a detrimental impact on plant growth and productivity. Hence, there is a substantial demand for key factors of stress responses to improve yield stability of crops. Members of the poly(ADP-ribose)polymerase (PARP) protein family, which post-translationally modify (PARylate) nuclear proteins, have been suggested as such universal determinants of plant stress responses. A role under abiotic stress has been inferred from studies in which a genetic or, more commonly, pharmacological inhibition of PARP activity improved the performance of stressed plants. To further elucidate the role of PARP proteins under stress, T-DNA knockout mutants for the three Arabidopsis thaliana PARP genes were subjected to drought, osmotic, salt, and oxidative stress. To exclude a functional redundancy, which was indicated by a transcriptional upregulation of the remaining parp genes, a parp triple mutant was generated. Surprisingly, parp mutant plants did not differ from wild type plants in any of these stress experiments, independent from the number of PARP genes mutated. The parp triple mutant was also analyzed for callose formation in response to the pathogenassociated molecular pattern flg22. Unexpectedly, callose formation was unaltered in the mutant, albeit pharmacological PARP inhibition robustly blocked this immune response, confirming previous reports. Evidently, pharmacological inhibition appears to be more robust than the abolition of all PARP genes, indicating the presence of so-far undescribed proteins with PARP activity. This was supported by the finding that protein PARylation was not absent, but even increased in the parp triple mutant. Candidates for novel PARP-inhibitor targets may be found in the SRO protein family. These proteins harbor a catalytic PARP-like domain and are centrally involved in stress responses. Molecular modeling analyses, employing animal PARPs as templates, indeed indicated a capability of the SRO proteins RCD1 and

  3. Aquatic macroinvertebrates associated with Eichhornia azurea (Swartz) Kunth and relationships with abiotic factors in marginal lentic ecosystems (São Paulo, Brazil).

    PubMed

    Silva, C V; Henry, R

    2013-02-01

    Marginal lakes are characterised by their having high biological diversity due to the presence of aquatic macrophytes in their coastal zones, providing habitats for refuge and food for animal community members. Among the fauna components associated with macrophytes, aquatic macroinvertebrates are important because they are an energy source for predators and fish. In six lakes and two different seasons (March and August 2009), the ecological attributes of aquatic macroinvertebrate community associated with Eichhornia azurea were compared and the controlling environmental factors were identified. Since the attributes of macroinvertebrate community are strictly associated with abiotic variables of each distinct habitat, our hypothesis was that each site associated with the same floating aquatic macrophyte (E. azurea) should have a typical composition and density of organisms. We identified 50 taxa of macroinvertebrates, with greater taxa richness for aquatic insects (37 taxa) divided into eight orders; the order Diptera being the most abundant in the two study periods. On the other hand, higher values of total taxa richness were recorded in August. Dissolved oxygen and pH presented the greatest number of significant positive correlations with the different taxa. The animals most frequently collected in the six lakes in March and August 2009 were Hirudinea, Oligochaeta, Hydrachnidae, Conchostraca, Ostracoda, Noteridae, Ceratopogonidae, Chironomidae, Culicidae, Caenidae, Pleidae, Aeshnidae, Libellulidae, Coenagrionidae and Nematoda. Only densities of Trichoptera, Ostracoda and Conchostraca presented the highest significant differences between lakes in both study periods and considering the composition of macroinvertebrates no significant differences were registered for macroinvertebrate composition.

  4. Interactions among biotic and abiotic factors affect the reliability of tungsten microneedles puncturing in vitro and in vivo peripheral nerves: A hybrid computational approach.

    PubMed

    Sergi, Pier Nicola; Jensen, Winnie; Yoshida, Ken

    2016-02-01

    Tungsten is an elective material to produce slender and stiff microneedles able to enter soft tissues and minimize puncture wounds. In particular, tungsten microneedles are used to puncture peripheral nerves and insert neural interfaces, bridging the gap between the nervous system and robotic devices (e.g., hand prostheses). Unfortunately, microneedles fail during the puncture process and this failure is not dependent on stiffness or fracture toughness of the constituent material. In addition, the microneedles' performances decrease during in vivo trials with respect to the in vitro ones. This further effect is independent on internal biotic effects, while it seems to be related to external biotic causes. Since the exact synergy of phenomena decreasing the in vivo reliability is still not known, this work explored the connection between in vitro and in vivo behavior of tungsten microneedles through the study of interactions between biotic and abiotic factors. A hybrid computational approach, simultaneously using theoretical relationships and in silico models of nerves, was implemented to model the change of reliability varying the microneedle diameter, and to predict in vivo performances by using in vitro reliability and local differences between in vivo and in vitro mechanical response of nerves.

  5. Interactive Effects of UV-B Light with Abiotic Factors on Plant Growth and Chemistry, and Their Consequences for Defense against Arthropod Herbivores.

    PubMed

    Escobar-Bravo, Rocio; Klinkhamer, Peter G L; Leiss, Kirsten A

    2017-01-01

    Ultraviolet-B (UV-B) light plays a crucial role in plant-herbivorous arthropods interactions by inducing changes in constitutive and inducible plant defenses. In particular, constitutive defenses can be modulated by UV-B-induced photomorphogenic responses and changes in the plant metabolome. In accordance, the prospective use of UV-B light as a tool to increase plant protection in agricultural practice has gained increasing interest. Changes in the environmental conditions might, however, modulate the UV-B -induced plant responses. While in some cases plant responses to UV-B can increase adaptation to changes in certain abiotic factors, UV-B-induced responses might be also antagonized by the changing environment. The outcome of these interactions might have a great influence on how plants interact with their enemies, e.g., herbivorous arthropods. Here, we provide a review on the interactive effects of UV-B and light quantity and quality, increased temperature and drought stress on plant biochemistry, and we discuss the implications of the outcome of these interactions for plant resistance to arthropod pests.

  6. Interactive Effects of UV-B Light with Abiotic Factors on Plant Growth and Chemistry, and Their Consequences for Defense against Arthropod Herbivores

    PubMed Central

    Escobar-Bravo, Rocio; Klinkhamer, Peter G. L.; Leiss, Kirsten A.

    2017-01-01

    Ultraviolet-B (UV-B) light plays a crucial role in plant–herbivorous arthropods interactions by inducing changes in constitutive and inducible plant defenses. In particular, constitutive defenses can be modulated by UV-B-induced photomorphogenic responses and changes in the plant metabolome. In accordance, the prospective use of UV-B light as a tool to increase plant protection in agricultural practice has gained increasing interest. Changes in the environmental conditions might, however, modulate the UV-B -induced plant responses. While in some cases plant responses to UV-B can increase adaptation to changes in certain abiotic factors, UV-B-induced responses might be also antagonized by the changing environment. The outcome of these interactions might have a great influence on how plants interact with their enemies, e.g., herbivorous arthropods. Here, we provide a review on the interactive effects of UV-B and light quantity and quality, increased temperature and drought stress on plant biochemistry, and we discuss the implications of the outcome of these interactions for plant resistance to arthropod pests. PMID:28303147

  7. Oxylipins and plant abiotic stress resistance.

    PubMed

    Savchenko, T V; Zastrijnaja, O M; Klimov, V V

    2014-04-01

    Oxylipins are signaling molecules formed enzymatically or spontaneously from unsaturated fatty acids in all aerobic organisms. Oxylipins regulate growth, development, and responses to environmental stimuli of organisms. The oxylipin biosynthesis pathway in plants includes a few parallel branches named after first enzyme of the corresponding branch as allene oxide synthase, hydroperoxide lyase, divinyl ether synthase, peroxygenase, epoxy alcohol synthase, and others in which various biologically active metabolites are produced. Oxylipins can be formed non-enzymatically as a result of oxygenation of fatty acids by free radicals and reactive oxygen species. Spontaneously formed oxylipins are called phytoprostanes. The role of oxylipins in biotic stress responses has been described in many published works. The role of oxylipins in plant adaptation to abiotic stress conditions is less studied; there is also obvious lack of available data compilation and analysis in this area of research. In this work we analyze data on oxylipins functions in plant adaptation to abiotic stress conditions, such as wounding, suboptimal light and temperature, dehydration and osmotic stress, and effects of ozone and heavy metals. Modern research articles elucidating the molecular mechanisms of oxylipins action by the methods of biochemistry, molecular biology, and genetics are reviewed here. Data on the role of oxylipins in stress signal transduction, stress-inducible gene expression regulation, and interaction of these metabolites with other signal transduction pathways in cells are described. In this review the general oxylipin-mediated mechanisms that help plants to adjust to a broad spectrum of stress factors are considered, followed by analysis of more specific responses regulated by oxylipins only under certain stress conditions. New approaches to improvement of plant resistance to abiotic stresses based on the induction of oxylipin-mediated processes are discussed.

  8. Changes in biotic and abiotic processes following mangrove clearing

    NASA Astrophysics Data System (ADS)

    Granek, Elise; Ruttenberg, Benjamin I.

    2008-12-01

    Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves ( Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an

  9. The influence of biotic and abiotic factors on (137)Cs accumulation in higher fungi after the accident at Chernobyl NPP.

    PubMed

    Zarubina, N

    2016-09-01

    Levels of soil contamination with (137)Cs, the belonging of fungi to a certain ecological group, the localization depth of the main part of mycelium in soil are the primary factors influencing the value of (137)Cs specific activity in higher fungi after the accident at Chernobyl NPP. It has been found that the value of (137)Cs specific activity in fungi of one species could vary by more than 10 times during a vegetation period. A correlation between the changes of (137)Cs content in fungi during the vegetation period and the amount of precipitates during various periods preceding the collection of samples has not been determined. An assumption has been proposed stating dependence between peculiarities of mycelium growth during the vegetation period and the changes of (137)Cs specific activity in fungi.

  10. Biotic and abiotic factors affecting the flight activity of Fopius arisanus, an egg-pupal parasitoid of fruit fly pests.

    PubMed

    Rousse, P; Gourdon, F; Roubaud, M; Chiroleu, F; Quilici, S

    2009-06-01

    Climatic conditions and the physiological state of a parasitoid may alter its host selection behavior and thus its efficiency as a biological control agent. We studied the influence of these parameters on the behavior of Fopius arisanus (Sonan), an egg-pupal parasitoid of many Tephritidae. In the first experiment, we assessed in field cage assays the influence of temperature, humidity, light intensity, barometric pressure, and wind speed. Both flight and parasitism were mainly affected by temperature and humidity. However, because these two factors were strongly correlated in our experiments, the direct influence of each one cannot be specified. Flight activity was affected by variations in barometric pressure. In a second set of experiments, we conducted release and recapture assays with dyed insects to determine the influence of sex, mating status, egg load, age, and starvation on attraction toward infested fruit. Males were not attracted, suggesting that fruit are not a mating site. The egg load seemed to be a major parameter of foraging motivation. Finally, we showed that flight activity strongly decreased after 48 h of starvation. We observed a possible switch to food in the foraging motivation of starved females, but this result was impaired by poor recoveries: <10% of released females were recaptured after 96 h of starvation. We finally discuss the importance of these observations on the efficiency of F. arisanus as a biological control agent in tropical humid areas.

  11. Molecular cloning and expression profile of an abiotic stress and hormone responsive MYB transcription factor gene from Panax ginseng.

    PubMed

    Afrin, Sadia; Zhu, Jie; Cao, Hongzhe; Huang, Jingjia; Xiu, Hao; Luo, Tiao; Luo, Zhiyong

    2015-04-01

    The v-myb avian myeloblastosis viral oncogene homolog (MYB) family constitutes one of the most abundant groups of transcription factors and plays vital roles in developmental processes and defense responses in plants. A ginseng (Panax ginseng C.A. Meyer) MYB gene was cloned and designated as PgMYB1. The cDNA of PgMYB1 is 762 base pairs long and encodes the R2R3-type protein consisting 238 amino acids. Subcellular localization showed that PgMYB1-mGFP5 fusion protein was specifically localized in the nucleus. To understand the functional roles of PgMYB1, we investigated the expression patterns of PgMYB1 in different tissues and under various conditions. Quantitative real-time polymerase chain reaction and western blot analysis showed that PgMYB1 was expressed at higher level in roots, leaves, and lateral roots than in stems and seeds. The expression of PgMYB1 was up-regulated by abscisic acid, salicylic acid, NaCl, and cold (chilling), and down-regulated by methyl jasmonate. These results suggest that PgMYB1 might be involved in responding to environmental stresses and hormones.

  12. Marine Invasion in the Mediterranean Sea: The Role of Abiotic Factors When There Is No Biological Resistance

    PubMed Central

    2012-01-01

    The tropical red alga Womersleyella setacea (Rhodomelaceae, Rhodophyta) is causing increasing concern in the Mediterranean Sea because of its invasive behavior. After its introduction it has colonized most Mediterranean areas, but the mechanism underlying its acclimatization and invasion process remains unknown. To understand this process, we decided i) to assess in situ the seasonal biomass and phenological patterns of populations inhabiting the Mediterranean Sea in relation to the main environmental factors, and ii) to experimentally determine if the tolerance of W. setacea to different light and temperature conditions can explain its colonization success, as well as its bathymetric distribution range. The bathymetric distribution, biomass, and phenology of W. setacea were studied at two localities, and related to irradiance and temperature values recorded in situ. Laboratory experiments were set up to study survival, growth and reproduction under contrasting light and temperature conditions in the short, mid, and long term.Results showed that, in the studied area, the bathymetric distribution of W. setacea is restricted to a depth belt between 25 and 40 m deep, reaching maximum biomass values (126 g dw m−2) at 30 m depth. In concordance, although in the short term W. setacea survived and grew in a large range of environmental conditions, its life requirements for the mid and long term were dim light levels and low temperatures. Biomass of Womersleyella setacea did not show any clear seasonal pattern, though minimum values were reported in spring. Reproductive structures were always absent. Bearing in mind that no herbivores feed on Womersleyella setacea and that its thermal preferences are more characteristic of temperate than of tropical seaweeds, low light (50 µmol photon m−2 s−1) and low temperature (12°C) levels are critical for W. setacea survival and growth, thus probably determining its spread and bathymetric distribution across the Mediterranean

  13. Marine invasion in the Mediterranean Sea: the role of abiotic factors when there is no biological resistance.

    PubMed

    Cebrian, Emma; Rodríguez-Prieto, Conxi

    2012-01-01

    The tropical red alga Womersleyella setacea (Rhodomelaceae, Rhodophyta) is causing increasing concern in the Mediterranean Sea because of its invasive behavior. After its introduction it has colonized most Mediterranean areas, but the mechanism underlying its acclimatization and invasion process remains unknown. To understand this process, we decided i) to assess in situ the seasonal biomass and phenological patterns of populations inhabiting the Mediterranean Sea in relation to the main environmental factors, and ii) to experimentally determine if the tolerance of W. setacea to different light and temperature conditions can explain its colonization success, as well as its bathymetric distribution range. The bathymetric distribution, biomass, and phenology of W. setacea were studied at two localities, and related to irradiance and temperature values recorded in situ. Laboratory experiments were set up to study survival, growth and reproduction under contrasting light and temperature conditions in the short, mid, and long term. Results showed that, in the studied area, the bathymetric distribution of W. setacea is restricted to a depth belt between 25 and 40 m deep, reaching maximum biomass values (126 g dw m(-2)) at 30 m depth. In concordance, although in the short term W. setacea survived and grew in a large range of environmental conditions, its life requirements for the mid and long term were dim light levels and low temperatures. Biomass of Womersleyella setacea did not show any clear seasonal pattern, though minimum values were reported in spring. Reproductive structures were always absent. Bearing in mind that no herbivores feed on Womersleyella setacea and that its thermal preferences are more characteristic of temperate than of tropical seaweeds, low light (50 µmol photon m(-2) s(-1)) and low temperature (12°C) levels are critical for W. setacea survival and growth, thus probably determining its spread and bathymetric distribution across the Mediterranean

  14. The Arabidopsis Transcription Factor ANAC032 Represses Anthocyanin Biosynthesis in Response to High Sucrose and Oxidative and Abiotic Stresses

    PubMed Central

    Mahmood, Kashif; Xu, Zhenhua; El-Kereamy, Ashraf; Casaretto, José A.; Rothstein, Steven J.

    2016-01-01

    Production of anthocyanins is one of the adaptive responses employed by plants during stress conditions. During stress, anthocyanin biosynthesis is mainly regulated at the transcriptional level via a complex interplay between activators and repressors of anthocyanin biosynthesis genes. In this study, we investigated the role of a NAC transcription factor, ANAC032, in the regulation of anthocyanin biosynthesis during stress conditions. ANAC032 expression was found to be induced by exogenous sucrose as well as high light (HL) stress. Using biochemical, molecular and transgenic approaches, we show that ANAC032 represses anthocyanin biosynthesis in response to sucrose treatment, HL and oxidative stress. ANAC032 was found to negatively affect anthocyanin accumulation and the expression of anthocyanin biosynthesis (DFR, ANS/LDOX) and positive regulatory (TT8) genes as demonstrated in overexpression line (35S:ANAC032) compared to wild-type under HL stress. The chimeric repressor line (35S:ANAC032-SRDX) exhibited the opposite expression patterns for these genes. The negative impact of ANAC032 on the expression of DFR, ANS/LDOX and TT8 was found to be correlated with the altered expression of negative regulators of anthocyanin biosynthesis, AtMYBL2 and SPL9. In addition to this, ANAC032 also repressed the MeJA- and ABA-induced anthocyanin biosynthesis. As a result, transgenic lines overexpressing ANAC032 (35S:ANAC032) produced drastically reduced levels of anthocyanin pigment compared to wild-type when challenged with salinity stress. However, transgenic chimeric repressor lines (35S:ANAC032-SRDX) exhibited the opposite phenotype. Our results suggest that ANAC032 functions as a negative regulator of anthocyanin biosynthesis in Arabidopsis thaliana during stress conditions. PMID:27790239

  15. Reactive oxygen species signaling in plants under abiotic stress.

    PubMed

    Choudhury, Shuvasish; Panda, Piyalee; Sahoo, Lingaraj; Panda, Sanjib Kumar

    2013-04-01

    Abiotic stresses like heavy metals, drought, salt, low temperature, etc. are the major factors that limit crop productivity and yield. These stresses are associated with production of certain deleterious chemical entities called reactive oxygen species (ROS), which include hydrogen peroxide (H₂O₂), superoxide radical (O₂(-)), hydroxyl radical (OH(-)), etc. ROS are capable of inducing cellular damage by degradation of proteins, inactivation of enzymes, alterations in the gene and interfere in various pathways of metabolic importance. Our understanding on ROS in response to abiotic stress is revolutionized with the advancements in plant molecular biology, where the basic understanding on chemical behavior of ROS is better understood. Understanding the molecular mechanisms involved in ROS generation and its potential role during abiotic stress is important to identify means by which plant growth and metabolism can be regulated under acute stress conditions. ROS mediated oxidative stress, which is the key to understand stress related toxicity have been widely studied in many plants and the results in those studies clearly revealed that oxidative stress is the main symptom of toxicity. Plants have their own antioxidant defense mechanisms to encounter ROS that is of enzymic and non-enzymic nature . Coordinated activities of these antioxidants regulate ROS detoxification and reduces oxidative load in plants. Though ROS are always regarded to impart negative impact on plants, some reports consider them to be important in regulating key cellular functions; however, such reports in plant are limited. Molecular approaches to understand ROS metabolism and signaling have opened new avenues to comprehend its critical role in abiotic stress. ROS also acts as secondary messenger that signals key cellular functions like cell proliferation, apoptosis and necrosis. In higher eukaryotes, ROS signaling is not fully understood. In this review we summarize our understanding on ROS

  16. Abiotic factors and their interactions influence on the co-production of aflatoxin B(1) and cyclopiazonic acid by Aspergillus flavus isolated from corn.

    PubMed

    Astoreca, Andrea; Vaamonde, Graciela; Dalcero, Ana; Marin, Sonia; Ramos, Antonio

    2014-04-01

    The objectives of this study were i) to determine the effects of the interactions of water activity, temperature and incubation time on the co-production of AFB1 and CPA by isolates of Aspergillus flavus with different profile of mycotoxin production and ii) to identify the aW and temperature limiting conditions for the production of both mycotoxins. Fungi used in this study were selected because they belonged to different chemotypes: chemotype I (AFB1+/CPA+), III (AFB1+/CPA-) and IV (AFB1-/CPA+), respectively. Two culture media were used; Czapek yeast agar (CYA) and corn extract agar (CEM), at different incubated temperatures (10-40 °C) and aW levels (0.80-0.98). AFB1 and CPA production were analyzed after 7, 14, 21 and 28 days of incubation. Significant differences were observed with respect to mycotoxin production depending on the media evaluated. The AFB1 production occurred more favorably on CYA while the highest CPA concentrations were recorded on CEM. Within the range of aW evaluated in this study, 0.83 was the limiting level for both toxins production. The optimum conditions for AFB1 production occurred at 0.96 aW and 30 °C after 21 days of incubation, regardless of the media and isolate. Although different amounts of toxins were produced in each medium, the limiting and optimum conditions for their production were similar in both. No differences in the response of the three isolates to the abiotic factors discussed were observed despite belonging to different chemotypes. The determination of the thresholds of mycotoxins co-production, especially in the case of data obtained with the corn extract medium can be useful to avoid the conditions conducive to co-occurrence of these mycotoxins in corn.

  17. Direct and indirect effects of climate on demography and early growth of Pinus sylvestris at the rear edge: changing roles of biotic and abiotic factors.

    PubMed

    Benavides, Raquel; Rabasa, Sonia G; Granda, Elena; Escudero, Adrián; Hódar, José A; Martínez-Vilalta, Jordi; Rincón, Ana M; Zamora, Regino; Valladares, Fernando

    2013-01-01

    Global change triggers shifts in forest composition, with warming and aridification being particularly threatening for the populations located at the rear edge of the species distributions. This is the case of Scots pine (Pinus sylvestris) in the Mediterranean Basin where uncertainties in relation to its dynamics under these changing scenarios are still high. We analysed the relative effect of climate on the recruitment patterns of Scots pine and its interactions with local biotic and abiotic variables at different spatial scales. Number of seedlings and saplings was surveyed, and their annual shoot growth measured in 96 plots located across altitudinal gradients in three different regions in the Iberian Peninsula. We found a significant influence of climate on demography and performance of recruits, with a non-linear effect of temperature on the presence of juveniles, and a positive effect of precipitation on their survival. Abundance of juveniles of P. sylvestris that underwent their first summer drought was skewed towards higher altitudes than the altitudinal mean range of the conspecific adults and the optimum elevation for seedlings' emergence. At local level, light availability did not influence juveniles' density, but it enhanced their growth. Biotic interactions were found between juveniles and the herb cover (competition) and between the number of newly emerged seedlings and shrubs (facilitation). Results also highlighted the indirect effect that climate exerts over the local factors, modulating the interactions with the pre-existing vegetation that were more evident at more stressful sites. This multiscale approach improves our understanding of the dynamics of these marginal populations and some management criteria can be inferred to boost their conservation under the current global warming.

  18. Abiotic tooth enamel

    NASA Astrophysics Data System (ADS)

    Yeom, Bongjun; Sain, Trisha; Lacevic, Naida; Bukharina, Daria; Cha, Sang-Ho; Waas, Anthony M.; Arruda, Ellen M.; Kotov, Nicholas A.

    2017-03-01

    Tooth enamel comprises parallel microscale and nanoscale ceramic columns or prisms interlaced with a soft protein matrix. This structural motif is unusually consistent across all species from all geological eras. Such invariability—especially when juxtaposed with the diversity of other tissues—suggests the existence of a functional basis. Here we performed ex vivo replication of enamel-inspired columnar nanocomposites by sequential growth of zinc oxide nanowire carpets followed by layer-by-layer deposition of a polymeric matrix around these. We show that the mechanical properties of these nanocomposites, including hardness, are comparable to those of enamel despite the nanocomposites having a smaller hard-phase content. Our abiotic enamels have viscoelastic figures of merit (VFOM) and weight-adjusted VFOM that are similar to, or higher than, those of natural tooth enamels—we achieve values that exceed the traditional materials limits of 0.6 and 0.8, respectively. VFOM values describe resistance to vibrational damage, and our columnar composites demonstrate that light-weight materials of unusually high resistance to structural damage from shocks, environmental vibrations and oscillatory stress can be made using biomimetic design. The previously inaccessible combinations of high stiffness, damping and light weight that we achieve in these layer-by-layer composites are attributed to efficient energy dissipation in the interfacial portion of the organic phase. The in vivo contribution of this interfacial portion to macroscale deformations along the tooth’s normal is maximized when the architecture is columnar, suggesting an evolutionary advantage of the columnar motif in the enamel of living species. We expect our findings to apply to all columnar composites and to lead to the development of high-performance load-bearing materials.

  19. Abiotic tooth enamel.

    PubMed

    Yeom, Bongjun; Sain, Trisha; Lacevic, Naida; Bukharina, Daria; Cha, Sang-Ho; Waas, Anthony M; Arruda, Ellen M; Kotov, Nicholas A

    2017-03-01

    Tooth enamel comprises parallel microscale and nanoscale ceramic columns or prisms interlaced with a soft protein matrix. This structural motif is unusually consistent across all species from all geological eras. Such invariability-especially when juxtaposed with the diversity of other tissues-suggests the existence of a functional basis. Here we performed ex vivo replication of enamel-inspired columnar nanocomposites by sequential growth of zinc oxide nanowire carpets followed by layer-by-layer deposition of a polymeric matrix around these. We show that the mechanical properties of these nanocomposites, including hardness, are comparable to those of enamel despite the nanocomposites having a smaller hard-phase content. Our abiotic enamels have viscoelastic figures of merit (VFOM) and weight-adjusted VFOM that are similar to, or higher than, those of natural tooth enamels-we achieve values that exceed the traditional materials limits of 0.6 and 0.8, respectively. VFOM values describe resistance to vibrational damage, and our columnar composites demonstrate that light-weight materials of unusually high resistance to structural damage from shocks, environmental vibrations and oscillatory stress can be made using biomimetic design. The previously inaccessible combinations of high stiffness, damping and light weight that we achieve in these layer-by-layer composites are attributed to efficient energy dissipation in the interfacial portion of the organic phase. The in vivo contribution of this interfacial portion to macroscale deformations along the tooth's normal is maximized when the architecture is columnar, suggesting an evolutionary advantage of the columnar motif in the enamel of living species. We expect our findings to apply to all columnar composites and to lead to the development of high-performance load-bearing materials.

  20. Diagnosing Abiotic Degradation

    EPA Science Inventory

    The abiotic degradation of chlorinated solvents in ground water can be difficult to diagnose. Under current practice, most of the “evidence” is negative; specifically the apparent disappearance of chlorinated solvents with an accumulation of vinyl chloride, ethane, ethylene, or ...

  1. Transcriptional networks-crops, clocks, and abiotic stress.

    PubMed

    Gehan, Malia A; Greenham, Kathleen; Mockler, Todd C; McClung, C Robertson

    2015-04-01

    Several factors affect the yield potential and geographical range of crops including the circadian clock, water availability, and seasonal temperature changes. In order to sustain and increase plant productivity on marginal land in the face of both biotic and abiotic stresses, we need to more efficiently generate stress-resistant crops through marker-assisted breeding, genetic modification, and new genome-editing technologies. To leverage these strategies for producing the next generation of crops, future transcriptomic data acquisition should be pursued with an appropriate temporal design and analyzed with a network-centric approach. The following review focuses on recent developments in abiotic stress transcriptional networks in economically important crops and will highlight the utility of correlation-based network analysis and applications.

  2. Transgenic expression of TaMYB2A confers enhanced tolerance to multiple abiotic stresses in Arabidopsis.

    PubMed

    Mao, Xinguo; Jia, Dongsheng; Li, Ang; Zhang, Hongying; Tian, Shanjun; Zhang, Xiaoke; Jia, Jizeng; Jing, Ruilian

    2011-09-01

    Osmotic stresses such as drought, salinity, and cold are major environmental factors that limit agricultural productivity. Transcription factors play essential roles in abiotic stress signaling in plants. Three TaMYB2 members were identified and designated TaMYB2A, TaMYB2B, and TaMYB2D based on their genomic origins. The cis-regulatory elements in the promoter regions were compared, and their diverse expression patterns under different abiotic stress conditions were identified. TaMYB2A was further characterized because of its earlier response to stresses. Subcellular localization revealed that TaMYB2A localized in the nucleus. To examine the role of TaMYB2A under various environmental stresses, transgenic Arabidopsis plants carrying TaMYB2A controlled by the CaMV 35S promoter were generated and subjected to severe abiotic stress. TaMYB2A transgenics had enhanced tolerance to drought, salt, and freezing stresses, which were confirmed by the enhanced expressions of abiotic stress-responsive genes and several physiological indices, including decreased rate of water loss, enhanced cell membrane stability, improved photosynthetic potential, and reduced osmotic potential. TaMYB2A is a multifunctional regulatory factor. Its overexpression confers enhanced tolerance to multiple abiotic stresses while having no obvious negative effects on phenotype under well-watered and stressed conditions; thus, TaMYB2A has the potential for utilization in transgenic breeding to improve abiotic stress tolerances in crops.

  3. Polyamines and abiotic stress tolerance in plants

    PubMed Central

    Gill, Sarvajeet Singh

    2010-01-01

    Environmental stresses including climate change, especially global warming, are severely affecting plant growth and productivity worldwide. It has been estimated that two-thirds of the yield potential of major crops are routinely lost due to the unfavorable environmental factors. On the other hand, the world population is estimated to reach about 10 billion by 2050, which will witness serious food shortages. Therefore, crops with enhanced vigour and high tolerance to various environmental factors should be developed to feed the increasing world population. Maintaining crop yields under adverse environmental stresses is probably the major challenge facing modern agriculture where polyamines can play important role. Polyamines (PAs)(putrescine, spermidine and spermine) are group of phytohormone-like aliphatic amine natural compounds with aliphatic nitrogen structure and present in almost all living organisms including plants. Evidences showed that polyamines are involved in many physiological processes, such as cell growth and development and respond to stress tolerance to various environmental factors. In many cases the relationship of plant stress tolerance was noted with the production of conjugated and bound polyamines as well as stimulation of polyamine oxidation. Therefore, genetic manipulation of crop plants with genes encoding enzymes of polyamine biosynthetic pathways may provide better stress tolerance to crop plants. Furthermore, the exogenous application of PAs is also another option for increasing the stress tolerance potential in plants. Here, we have described the synthesis and role of various polyamines in abiotic stress tolerance in plants. PMID:20592804

  4. Transcriptomic Profiling of the Maize (Zea mays L.) Leaf Response to Abiotic Stresses at the Seedling Stage.

    PubMed

    Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng

    2017-01-01

    Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize (Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses.

  5. Transcriptomic Profiling of the Maize (Zea mays L.) Leaf Response to Abiotic Stresses at the Seedling Stage

    PubMed Central

    Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng

    2017-01-01

    Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize (Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses. PMID:28298920

  6. Monthly Distribution of Phlebotomine Sand Flies, and Biotic and Abiotic Factors Related to Their Abundance, in an Urban Area to Which Visceral Leishmaniasis Is Endemic in Corumbá, Brazil

    PubMed Central

    Casaril, Aline Etelvina; Fernandes, Wagner Souza; Ravanelli, Michelle de Saboya; Paranhos Filho, Antônio Conceição; Oshiro, Elisa Teruya; de Oliveira, Alessandra Gutierrez

    2016-01-01

    The monthly distribution and abundance of sand flies are influenced by both biotic and abiotic factors. The present study aimed to evaluate the seasonal distribution of sand flies and the relation between their abundance and environmental parameters, including vegetation and climate. This study was conducted over a 2-year period (April 2012 to March 2014). Monthly distribution was evaluated through the weekly deployment of CDC light traps in the peridomicile area of 5 residences in an urban area of the municipality of Corumbá in the State of Mato Grosso do Sul, Brazil. Meteorological data were obtained from the Mato Grosso do Sul Center for Weather, Climate, and Water Resources. The spectral indices were calculated based on spatial resolution images (GeoEye) and the percentage of vegetal coverage. Differences in the abundance of sand flies among the collection sites were assessed using the Kruskal-Wallis test, and the strength of correlations between environmental variables was determined by calculating Spearman’s correlation coefficients. Lutzomyia cruzi, Lu. forattinii, and Evandromyia corumbaensis were the most frequently found species. Although no significant association was found among these sand fly species and the tested environmental variables (vegetation and climate), high population peaks were found during the rainy season, whereas low peaks were observed in the dry season. The monthly distribution of sand flies was primarily determined by Lu. cruzi, which accounted for 93.94% of the specimens collected each month throughout the experimental period. The fact that sand flies were detected year-round indicates a continuous risk of infection to humans, demonstrating the need for targeted management and education programs. PMID:27783667

  7. Monthly Distribution of Phlebotomine Sand Flies, and Biotic and Abiotic Factors Related to Their Abundance, in an Urban Area to Which Visceral Leishmaniasis Is Endemic in Corumbá, Brazil.

    PubMed

    Falcão de Oliveira, Everton; Casaril, Aline Etelvina; Fernandes, Wagner Souza; Ravanelli, Michelle de Saboya; Medeiros, Márcio José de; Gamarra, Roberto Macedo; Paranhos Filho, Antônio Conceição; Oshiro, Elisa Teruya; Oliveira, Alessandra Gutierrez de; Galati, Eunice Aparecida Bianchi

    2016-01-01

    The monthly distribution and abundance of sand flies are influenced by both biotic and abiotic factors. The present study aimed to evaluate the seasonal distribution of sand flies and the relation between their abundance and environmental parameters, including vegetation and climate. This study was conducted over a 2-year period (April 2012 to March 2014). Monthly distribution was evaluated through the weekly deployment of CDC light traps in the peridomicile area of 5 residences in an urban area of the municipality of Corumbá in the State of Mato Grosso do Sul, Brazil. Meteorological data were obtained from the Mato Grosso do Sul Center for Weather, Climate, and Water Resources. The spectral indices were calculated based on spatial resolution images (GeoEye) and the percentage of vegetal coverage. Differences in the abundance of sand flies among the collection sites were assessed using the Kruskal-Wallis test, and the strength of correlations between environmental variables was determined by calculating Spearman's correlation coefficients. Lutzomyia cruzi, Lu. forattinii, and Evandromyia corumbaensis were the most frequently found species. Although no significant association was found among these sand fly species and the tested environmental variables (vegetation and climate), high population peaks were found during the rainy season, whereas low peaks were observed in the dry season. The monthly distribution of sand flies was primarily determined by Lu. cruzi, which accounted for 93.94% of the specimens collected each month throughout the experimental period. The fact that sand flies were detected year-round indicates a continuous risk of infection to humans, demonstrating the need for targeted management and education programs.

  8. The Importance of Biotic vs. Abiotic Drivers of Local Plant Community Composition Along Regional Bioclimatic Gradients.

    PubMed

    Klanderud, Kari; Vandvik, Vigdis; Goldberg, Deborah

    2015-01-01

    We assessed if the relative importance of biotic and abiotic factors for plant community composition differs along environmental gradients and between functional groups, and asked which implications this may have in a warmer and wetter future. The study location is a unique grid of sites spanning regional-scale temperature and precipitation gradients in boreal and alpine grasslands in southern Norway. Within each site we sampled vegetation and associated biotic and abiotic factors, and combined broad- and fine-scale ordination analyses to assess the relative explanatory power of these factors for species composition. Although the community responses to biotic and abiotic factors did not consistently change as predicted along the bioclimatic gradients, abiotic variables tended to explain a larger proportion of the variation in species composition towards colder sites, whereas biotic variables explained more towards warmer sites, supporting the stress gradient hypothesis. Significant interactions with precipitation suggest that biotic variables explained more towards wetter climates in the sub alpine and boreal sites, but more towards drier climates in the colder alpine. Thus, we predict that biotic interactions may become more important in alpine and boreal grasslands in a warmer future, although more winter precipitation may counteract this trend in oceanic alpine climates. Our results show that both local and regional scales analyses are needed to disentangle the local vegetation-environment relationships and their regional-scale drivers, and biotic interactions and precipitation must be included when predicting future species assemblages.

  9. Robust Programming Problems Based on the Mean-Variance Model Including Uncertainty Factors

    NASA Astrophysics Data System (ADS)

    Hasuike, Takashi; Ishii, Hiroaki

    2009-01-01

    This paper considers robust programming problems based on the mean-variance model including uncertainty sets and fuzzy factors. Since these problems are not well-defined problems due to fuzzy factors, it is hard to solve them directly. Therefore, introducing chance constraints, fuzzy goals and possibility measures, the proposed models are transformed into the deterministic equivalent problems. Furthermore, in order to solve these equivalent problems efficiently, the solution method is constructed introducing the mean-absolute deviation and doing the equivalent transformations.

  10. RBM25 Mediates Abiotic Responses in Plants

    PubMed Central

    Cheng, Chunhong; Wang, Zhijuan; Yuan, Bingjian; Li, Xia

    2017-01-01

    Alternative splicing (AS) of pre-mRNAs is one of the most important post-transcriptional regulations that enable a single gene to code for multiple proteins resulting in the biodiversity of proteins in eukaryotes. Recently, we have shown that an Arabidopsis thaliana RNA recognition motif-containing protein RBM25 is a novel splicing factor to modulate plant response to ABA during seed germination and post-germination through regulating HAB1 pre-mRNA AS. Here, we show that RBM25 is preferentially expressed in stomata and vascular tissues in Arabidopsis and is induced by ABA and abiotic stresses. Loss-of-function mutant is highly tolerant to drought and sensitive to salt stress. Bioinformatic analysis and expression assays reveal that Arabidopsis RBM25 is induced by multiple abiotic stresses, suggesting a crucial role of RBM25 in Arabidopsis responses to adverse environmental conditions. Furthermore, we provide a comprehensive characterization of the homologous genes of Arabidopsis RBM25 based on the latest plant genome sequences and public microarray databases. Fourteen homologous genes are identified in different plant species which show similar structure in gene and protein. Notably, the promoter analysis reveals that RBM25 homologs are likely controlled by the regulators involved in multiple plant growth and abiotic stresses, such as drought and unfavorable temperature. The comparative analysis of general and unique cis regulatory elements of the RBM25 homologs highlights the conserved and unique molecular processes that modulate plant response to abiotic stresses through RBM25-mediated alternative splicing. PMID:28344583

  11. RBM25 Mediates Abiotic Responses in Plants.

    PubMed

    Cheng, Chunhong; Wang, Zhijuan; Yuan, Bingjian; Li, Xia

    2017-01-01

    Alternative splicing (AS) of pre-mRNAs is one of the most important post-transcriptional regulations that enable a single gene to code for multiple proteins resulting in the biodiversity of proteins in eukaryotes. Recently, we have shown that an Arabidopsis thaliana RNA recognition motif-containing protein RBM25 is a novel splicing factor to modulate plant response to ABA during seed germination and post-germination through regulating HAB1 pre-mRNA AS. Here, we show that RBM25 is preferentially expressed in stomata and vascular tissues in Arabidopsis and is induced by ABA and abiotic stresses. Loss-of-function mutant is highly tolerant to drought and sensitive to salt stress. Bioinformatic analysis and expression assays reveal that Arabidopsis RBM25 is induced by multiple abiotic stresses, suggesting a crucial role of RBM25 in Arabidopsis responses to adverse environmental conditions. Furthermore, we provide a comprehensive characterization of the homologous genes of Arabidopsis RBM25 based on the latest plant genome sequences and public microarray databases. Fourteen homologous genes are identified in different plant species which show similar structure in gene and protein. Notably, the promoter analysis reveals that RBM25 homologs are likely controlled by the regulators involved in multiple plant growth and abiotic stresses, such as drought and unfavorable temperature. The comparative analysis of general and unique cis regulatory elements of the RBM25 homologs highlights the conserved and unique molecular processes that modulate plant response to abiotic stresses through RBM25-mediated alternative splicing.

  12. Influence of abiotic stress signals on secondary metabolites in plants

    PubMed Central

    Ramakrishna, Akula; Ravishankar, Gokare Aswathanarayana

    2011-01-01

    Plant secondary metabolites are unique sources for pharmaceuticals, food additives, flavors, and industrially important biochemicals. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Secondary metabolites play a major role in the adaptation of plants to the environment and in overcoming stress conditions. Environmental factors viz. temperature, humidity, light intensity, the supply of water, minerals, and CO2 influence the growth of a plant and secondary metabolite production. Drought, high salinity, and freezing temperatures are environmental conditions that cause adverse effects on the growth of plants and the productivity of crops. Plant cell culture technologies have been effective tools for both studying and producing plant secondary metabolites under in vitro conditions and for plant improvement. This brief review summarizes the influence of different abiotic factors include salt, drought, light, heavy metals, frost etc. on secondary metabolites in plants. The focus of the present review is the influence of abiotic factors on secondary metabolite production and some of important plant pharmaceuticals. Also, we describe the results of in vitro cultures and production of some important secondary metabolites obtained in our laboratory. PMID:22041989

  13. The Arabidopsis ETHYLENE RESPONSE FACTOR1 Regulates Abiotic Stress-Responsive Gene Expression by Binding to Different cis-Acting Elements in Response to Different Stress Signals1[W][OA

    PubMed Central

    Cheng, Mei-Chun; Liao, Po-Ming; Kuo, Wei-Wen; Lin, Tsan-Piao

    2013-01-01

    ETHYLENE RESPONSE FACTOR1 (ERF1) is an upstream component in both jasmonate (JA) and ethylene (ET) signaling and is involved in pathogen resistance. Accumulating evidence suggests that ERF1 might be related to the salt stress response through ethylene signaling. However, the specific role of ERF1 in abiotic stress and the molecular mechanism underlying the signaling cross talk still need to be elucidated. Here, we report that ERF1 was highly induced by high salinity and drought stress in Arabidopsis (Arabidopsis thaliana). The salt stress induction required both JA and ET signaling but was inhibited by abscisic acid. ERF1-overexpressing lines (35S:ERF1) were more tolerant to drought and salt stress. They also displayed constitutively smaller stomatal aperture and less transpirational water loss. Surprisingly, 35S:ERF1 also showed enhanced heat tolerance and up-regulation of heat tolerance genes compared with the wild type. Several suites of genes activated by JA, drought, salt, and heat were found in microarray analysis of 35S:ERF1. Chromatin immunoprecipitation assays found that ERF1 up-regulates specific suites of genes in response to different abiotic stresses by stress-specific binding to GCC or DRE/CRT. In response to biotic stress, ERF1 bound to GCC boxes but not DRE elements; conversely, under abiotic stress, we observed specific binding of ERF1 to DRE elements. Furthermore, ERF1 bound preferentially to only one among several GCC box or DRE/CRT elements in the promoter region of its target genes. ERF1 plays a positive role in salt, drought, and heat stress tolerance by stress-specific gene regulation, which integrates JA, ET, and abscisic acid signals. PMID:23719892

  14. Nuclear actin activates human transcription factor genes including the OCT4 gene.

    PubMed

    Yamazaki, Shota; Yamamoto, Koji; Tokunaga, Makio; Sakata-Sogawa, Kumiko; Harata, Masahiko

    2015-01-01

    RNA microarray analyses revealed that nuclear actin activated many human transcription factor genes including OCT4, which is required for gene reprogramming. Oct4 is known to be activated by nuclear actin in Xenopus oocytes. Our findings imply that this process of OCT4 activation is conserved in vertebrates and among cell types and could be used for gene reprogramming of human cells.

  15. Abiotic stresses induce different localizations of anthocyanins in Arabidopsis

    PubMed Central

    Kovinich, Nik; Kayanja, Gilbert; Chanoca, Alexandra; Otegui, Marisa S; Grotewold, Erich

    2015-01-01

    Anthocyanins are induced in plants in response to abiotic stresses such as drought, high salinity, excess light, and cold, where they often correlate with enhanced stress tolerance. Numerous roles have been proposed for anthocyanins induced during abiotic stresses including functioning as ROS scavengers, photoprotectants, and stress signals. We have recently found different profiles of anthocyanins in Arabidopsis (Arabidopsis thaliana) plants exposed to different abiotic stresses, suggesting that not all anthocyanins have the same function. Here, we discuss these findings in the context of other studies and show that anthocyanins induced in Arabidopsis in response to various abiotic stresses have different localizations at the organ and tissue levels. These studies provide a basis to clarify the role of particular anthocyanin species during abiotic stress. PMID:26179363

  16. Abiotic Bromination of Soil Organic Matter.

    PubMed

    Leri, Alessandra C; Ravel, Bruce

    2015-11-17

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide and assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.

  17. DNA Damage Response Factors from Diverse Pathways, Including DNA Crosslink Repair, Mediate Alternative End Joining

    PubMed Central

    Howard, Sean M.; Yanez, Diana A.; Stark, Jeremy M.

    2015-01-01

    Alternative end joining (Alt-EJ) chromosomal break repair involves bypassing classical non-homologous end joining (c-NHEJ), and such repair causes mutations often with microhomology at the repair junction. Since the mediators of Alt-EJ are not well understood, we have sought to identify DNA damage response (DDR) factors important for this repair event. Using chromosomal break reporter assays, we surveyed an RNAi library targeting known DDR factors for siRNAs that cause a specific decrease in Alt-EJ, relative to an EJ event that is a composite of Alt-EJ and c-NHEJ (Distal-EJ between two tandem breaks). From this analysis, we identified several DDR factors that are specifically important for Alt-EJ relative to Distal-EJ. While these factors are from diverse pathways, we also found that most of them also promote homologous recombination (HR), including factors important for DNA crosslink repair, such as the Fanconi Anemia factor, FANCA. Since bypass of c-NHEJ is likely important for both Alt-EJ and HR, we disrupted the c-NHEJ factor Ku70 in Fanca-deficient mouse cells and found that Ku70 loss significantly diminishes the influence of Fanca on Alt-EJ. In contrast, an inhibitor of poly ADP-ribose polymerase (PARP) causes a decrease in Alt-EJ that is enhanced by Ku70 loss. Additionally, the helicase/nuclease DNA2 appears to have distinct effects from FANCA and PARP on both Alt-EJ, as well as end resection. Finally, we found that the proteasome inhibitor Bortezomib, a cancer therapeutic that has been shown to disrupt FANC signaling, causes a significant reduction in both Alt-EJ and HR, relative to Distal-EJ, as well as a substantial loss of end resection. We suggest that several distinct DDR functions are important for Alt-EJ, which include promoting bypass of c-NHEJ and end resection. PMID:25629353

  18. Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

    PubMed Central

    dos Reis, Sávio Pinho; Lima, Aline Medeiros; de Souza, Cláudia Regina Batista

    2012-01-01

    Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops. PMID:22942725

  19. The spindle-shaped cells in cutaneous Kaposi's sarcoma. Histologic simulators include factor XIIIa dermal dendrocytes.

    PubMed Central

    Nickoloff, B. J.; Griffiths, C. E.

    1989-01-01

    Kaposi's sarcoma is a neoplasm that develops as multifocal lesions, often involving the skin, characterized by a complex histologic picture including numerous vascular spaces, perivascular and interstitial spindle-shaped cells, and extravasated erythrocytes, lymphocytes, and plasma cells. Using an antibody against factor XIIIa, which identifies dermal dendrocytes, numerous factor XIIIa-positive dermal dendrocytes were detected among the spindle-shaped cells in 12 acquired immune deficiency syndrome (AIDS)-associated, and five non-AIDS-associated Kaposi's sarcoma lesions. The factor XIIIa-positive dermal dendrocytes were also increased in histologic simulators of Kaposi's sarcoma such as dermatofibroma, angiomatoid malignant fibrous histiocytoma, granuloma annulare, and early wound healing, but were absent in keloids. The increased number of dermal dendrocytes, which are often in an angiocentric configuration and which also express CD4, lymphocyte function associated antigen-1 (LFA-1), and Leu M3 in Kaposi's sarcoma, may be important to the angioproliferative response. The results suggested that the spindle-shaped cells that are present in a variety of cutaneous lesions are dermal dendrocytes and belong to the reticuloendothelial system, unlike other mesenchymal cell types such as the endothelial cell. Apparently a diverse array of stimuli, including human immunodeficiency virus type-1 (HIV-1) infection and trauma, can stimulate the accumulation of factor XIIIa expressing dermal dendrocytes in the skin. These cells can then participate in different stages of a variety of cutaneous alterations including Kaposi's sarcoma, dermatofibroma, granuloma annulare, and early wound healing. Thus, the factor XIIIa-positive dermal dendrocyte is a common cellular denominator among diverse clinical entities that share some histologic features. Images Figure 1 Figure 2 Figure 3 p797-a PMID:2573283

  20. Genome-wide analysis and expression patterns of ZF-HD transcription factors under different developmental tissues and abiotic stresses in Chinese cabbage.

    PubMed

    Wang, Wenli; Wu, Peng; Li, Ying; Hou, XiLin

    2016-06-01

    The ZF-HD gene family plays an important role in plant developmental processes and stress responses. However, the function of the ZF-HD genes in Chinese cabbage remains largely unknown. Chinese cabbage (Brassica rapa ssp. pekinensis) is a member of one of the most important leaf vegetables grown worldwide. The entire Chinese cabbage genome sequence has been determined, and more than forty thousand proteins have been identified to date. In this study, 31 ZF-HD genes were identified in Chinese cabbage. We show here that the BraZF-HD genes could be categorized into ZHD and MIF subfamilies. Among them, ZHD genes are plant-specific, nearly all intronless, and related to MINI ZINC FINGER genes that possess only the zinc finger. Phylogenetic analysis suggested that ZHDs have expanded considerably during angiosperm evolution. In addition, the ZHD group has 24 members, which is twice as much as the Arabidopsis ZHD group, indicating that the Chinese cabbage ZHD genes have been retained more frequently than other group genes. Real-time PCR analysis showed that most of BraZF-HD genes are preferentially expressed in flower. Furthermore, most of these genes are significantly induced under photoperiod or vernalization conditions, as well as abiotic stresses. Thereby implying that they may play important roles in these processes. This study provides insight into the evolution of ZF-HD genes in Chinese cabbage genome and may aid efforts to further characterize the function of these predicted ZF-HD genes in flowering and resistance.

  1. Abiotic and biotic factors influencing the mobility of arsenic in groundwater of a through-flow island in the Okavango Delta, Botswana

    NASA Astrophysics Data System (ADS)

    Mladenov, Natalie; Wolski, Piotr; Hettiarachchi, Ganga M.; Murray-Hudson, Michael; Enriquez, Hersy; Damaraju, Sivaramakrishna; Galkaduwa, Madhubhashini B.; McKnight, Diane M.; Masamba, Wellington

    2014-10-01

    The Okavango Delta of Botswana is a large arid-zone wetland comprising 20,000 km2 of permanent and seasonal floodplains and over 100,000 islands. It has been shown that island groundwater can have very high dissolved arsenic (As) concentration, but the abiotic and biotic controls on As mobility are not well understood in this setting. At New Island, an island located in the seasonal swamp, dissolved As concentration increased from below detection limits in the surface water to 180 μg/L in groundwater, present as As(III) species. We investigated the relative importance of hydrologic, geochemical, and geomicrobial processes, as well as influences of recent extreme flooding events, in mobilizing and sequestering As in the shallow groundwater system under this island. Our results suggest that evapotranspiration and through-flow conditions control the location of the high arsenic zone. A combination of processes is hypothesized to control elevated As in the concentration zone of New Island: high evapotranspiration rates concentrate As and other solutes, more alkaline pH leads to desorption of arsenic or dissolution of arsenic sulfides, and formation of thioarsenic complexes acts to keep arsenic in solution. Evidence from X-ray absorption near-edge structure spectroscopy (XANES) and sulfate reducing bacteria (SRB) measurements further suggests that SRBs influence arsenic sequestration as orpiment (As2S3). Although dissolved organic matter (DOM) was not significantly correlated to dissolved As in the groundwater, our results suggest that DOM may serve as an electron donor for sulfate reduction or other microbial reactions that influence redox state and As mobility. These results have important implications for water management in the region and in other large wetland environments. The processes evaluated in this study are also relevant for arsenic removal in subsurface constructed wetland systems that may exhibit rapidly changing processes over small spatial scales.

  2. Natural abiotic formation of oxalic acid in soils: results from aromatic model compounds and soil samples.

    PubMed

    Studenroth, Sabine; Huber, Stefan G; Kotte, Karsten; Schöler, Heinz F

    2013-02-05

    Oxalic acid is the smallest dicarboxylic acid and plays an important role in soil processes (e.g., mineral weathering and metal detoxification in plants). We have first proven its abiotic formation in soils and investigated natural abiotic degradation processes based on the oxidation of soil organic matter, enhanced by Fe(3+) and H(2)O(2) as hydroxyl radical suppliers. Experiments with the model compound catechol and further hydroxylated benzenes were performed to examine a common degradation pathway and to presume a general formation mechanism of oxalic acid. Two soil samples were tested for the release of oxalic acid and the potential effects of various soil parameters on oxalic acid formation. Additionally, the soil samples were treated with different soil sterilization methods to prove the oxalic acid formation under abiotic soil conditions. Different series of model experiments were conducted to determine a range of factors including Fe(3+), H(2)O(2), reaction time, pH, and chloride concentration on oxalic acid formation. Under certain conditions, catechol is degraded up to 65.6% to oxalic acid referring to carbon. In serial experiments with two soil samples, oxalic acid was produced, and the obtained results are suggestive of an abiotic degradation process. In conclusion, Fenton-like conditions with low Fe(3+) concentrations and an excess of H(2)O(2) as well as acidic conditions were required for an optimal oxalic acid formation. The presence of chloride reduced oxalic acid formation.

  3. Biotic and Abiotic Stresses Activate Different Ca2+ Permeable Channels in Arabidopsis

    PubMed Central

    Cao, Xiao-Qiang; Jiang, Zhong-Hao; Yi, Yan-Yan; Yang, Yi; Ke, Li-Ping; Pei, Zhen-Ming; Zhu, Shan

    2017-01-01

    To survive, plants must respond rapidly and effectively to various stress factors, including biotic and abiotic stresses. Salinity stress triggers the increase of cytosolic free Ca2+ concentration ([Ca2+]i) via Ca2+ influx across the plasma membrane, as well as bacterial flg22 and plant endogenous peptide Pep1. However, the interaction between abiotic stress-induced [Ca2+]i increases and biotic stress-induced [Ca2+]i increases is still not clear. Employing an aequorin-based Ca2+ imaging assay, in this work, we investigated the [Ca2+]i changes in response to flg22, Pep1, and NaCl treatments in Arabidopsis thaliana. We observed an additive effect on the [Ca2+]i increase which induced by flg22, Pep1, and NaCl. Our results indicate that biotic and abiotic stresses may activate different Ca2+ permeable channels. Further, calcium signal induced by biotic and abiotic stresses was independent in terms of spatial and temporal patterning. PMID:28197161

  4. Unraveling the role of fungal symbionts in plant abiotic stress tolerance

    PubMed Central

    Singh, Lamabam Peter

    2011-01-01

    Fungal symbionts have been found to be associated with every plant studied in the natural ecosystem, where they colonize and reside entirely or partially in the internal tissues of their host plant. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress and heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is an increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered. PMID:21512319

  5. Simultaneous expression of abiotic stress responsive transcription factors, AtDREB2A, AtHB7 and AtABF3 improves salinity and drought tolerance in peanut (Arachis hypogaea L.).

    PubMed

    Pruthvi, Vittal; Narasimhan, Rama; Nataraja, Karaba N

    2014-01-01

    Drought, salinity and extreme temperatures are the most common abiotic stresses, adversely affecting plant growth and productivity. Exposure of plants to stress activates stress signalling pathways that induce biochemical and physiological changes essential for stress acclimation. Stress tolerance is governed by multiple traits, and importance of a few traits in imparting tolerance has been demonstrated. Under drought, traits linked to water mining and water conservation, water use efficiency and cellular tolerance (CT) to desiccation are considered to be relevant. In this study, an attempt has been made to improve CT in drought hardy crop, peanut (Arachis hypogaea L., cv. TMV2) by co-expressing stress-responsive transcription factors (TFs), AtDREB2A, AtHB7 and AtABF3, associated with downstream gene expression. Transgenic plants simultaneously expressing these TFs showed increased tolerance to drought, salinity and oxidative stresses compared to wild type, with an increase in total plant biomass. The transgenic plants exhibited improved membrane and chlorophyll stability due to enhanced reactive oxygen species scavenging and osmotic adjustment by proline synthesis under stress. The improvement in stress tolerance in transgenic lines were associated with induced expression of various CT related genes like AhGlutaredoxin, AhAldehyde reductase, AhSerine threonine kinase like protein, AhRbx1, AhProline amino peptidase, AhHSP70, AhDIP and AhLea4. Taken together the results indicate that co-expression of stress responsive TFs can activate multiple CT pathways, and this strategy can be employed to improve abiotic stress tolerance in crop plants.

  6. Analysis of the lifted weight including height and frequency factors for workers in Colombia.

    PubMed

    Saavedra-Robinson, Luisa; Quintana, Leonardo A J; Fortunato Leal, Luis Díaz; Niño, María

    2012-01-01

    Factors related to the height of the load and the frequency of handling have become a way to predict the acceptable standard weight lifted for workers whose main task is the manual lifting of materials and measuring the conditions is important to determine a maximum weight lifted. This study was conducted to twenty (20) workers between eighteen (18) and forty (40) years old with a minimum six months experience and belonging to the warehouse and packaging area of a dairy products company. Consideration was given to three different heights such as knuckle, shoulder and total height as well as frequencies of 2, 4 and 6 times per minute. Average values for lifted weight were 17.9306 ± 2.37 kg. The conclusions and recommendations included a review of legislation related to Colombian maximum acceptable weight of lifting due to the current law does not match the acceptable weight handled in this research.

  7. Influence of salinity and temperature on the physiology of Limia melanonotata (Cyprinodontiformes: Poeciliidae): A search for abiotic factors limiting insular distribution in Hispaniola

    USGS Publications Warehouse

    Haney, D.C.; Walsh, S.J.

    2003-01-01

    We investigated salinity and temperature effects on routine metabolic rate (RMR), temperature tolerance (CTMax, critical thermal maximum), and salinity tolerance of Limia melanonotata, a poecliid fish that occurs in west-central inland waters of Hispaniola. Routine metabolic rate and CTMax were measured in fish acclimated to three salinities (0, 30, and 60 ppt) and temperatures (25??, 30??, and 35??C) for nine temperature-salinity combinations. Salinity and temperature did not significantly interact in their effect on RMR. For combined salinity acclimations, adjusted RMR (ANCOVA) was significantly lower at 25??C than either 30?? or 35??C. For combined temperature acclimations, mean RMR was significantly lower at 60 ppt than either 0 or 30 ppt. Salinity and temperature had a significant interactive effect on temperature tolerance. Mean CTMax was significantly higher at 30?? than 25??C at all salinities, but at 35??C was significantly higher than at 25?? or 30??C only among fish acclimated in fresh water. Fish exposed to a chronic increase in salinity experienced most mortality in a salinity range of 70-107 ppt, with females exhibiting greater salinity tolerance than males. Limia melanonotata approaches the upper extreme in salinity and temperature tolerances known for poeciliids. Our results also suggest that L. melanonotata may reduce energy expenditures at environmental extremes to tolerate harsh conditions for extended periods. Despite its curythermal and euryhaline adaptations, L. melanonotata has a relatively restricted inland range in Hispaniola and is unknown from inshore brackish or marine habitats. The present distribution of this species and congeners may be the result of a combination of factors that include historical zoogeography and ecological requirements.

  8. A decision support system prototype including human factors based on the TOGA meta-theory approach

    SciTech Connect

    Cappelli, M.; Memmi, F.; Gadomski, A. M.; Sepielli, M.

    2012-07-01

    The human contribution to the risk of operation of complex technological systems is often not negligible and sometimes tends to become significant, as shown by many reports on incidents and accidents occurred in the past inside Nuclear Power Plants (NPPs). An error of a human operator of a NPP can derive by both omission and commission. For instance, complex commission errors can also lead to significant catastrophic technological accidents, as for the case of the Three Mile Island accident. Typically, the problem is analyzed by focusing on the single event chain that has provoked the incident or accident. What is needed is a general framework able to include as many parameters as possible, i.e. both technological and human factors. Such a general model could allow to envisage an omission or commission error before it can happen or, alternatively, suggest preferred actions to do in order to take countermeasures to neutralize the effect of the error before it becomes critical. In this paper, a preliminary Decision Support System (DSS) based on the so-called (-) TOGA meta-theory approach is presented. The application of such a theory to the management of nuclear power plants has been presented in the previous ICAPP 2011. Here, a human factor simulator prototype is proposed in order to include the effect of human errors in the decision path. The DSS has been developed using a TRIGA research reactor as reference plant, and implemented using the LabVIEW programming environment and the Finite State Machine (FSM) model The proposed DSS shows how to apply the Universal Reasoning Paradigm (URP) and the Universal Management Paradigm (UMP) to a real plant context. The DSS receives inputs from instrumentation data and gives as output a suggested decision. It is obtained as the result of an internal elaborating process based on a performance function. The latter, describes the degree of satisfaction and efficiency, which are dependent on the level of responsibility related to

  9. The Arabidopsis PLAT domain protein1 is critically involved in abiotic stress tolerance.

    PubMed

    Hyun, Tae Kyung; van der Graaff, Eric; Albacete, Alfonso; Eom, Seung Hee; Großkinsky, Dominik K; Böhm, Hannah; Janschek, Ursula; Rim, Yeonggil; Ali, Walid Wahid; Kim, Soo Young; Roitsch, Thomas

    2014-01-01

    Despite the completion of the Arabidopsis genome sequence, for only a relatively low percentage of the encoded proteins experimental evidence concerning their function is available. Plant proteins that harbour a single PLAT (Polycystin, Lipoxygenase, Alpha-toxin and Triacylglycerol lipase) domain and belong to the PLAT-plant-stress protein family are ubiquitously present in monocot and dicots. However, the function of PLAT-plant-stress proteins is still poorly understood. Therefore, we have assessed the function of the uncharacterised Arabidopsis PLAT-plant-stress family members through a combination of functional genetic and physiological approaches. PLAT1 overexpression conferred increased abiotic stress tolerance, including cold, drought and salt stress, while loss-of-function resulted in opposite effects on abiotic stress tolerance. Strikingly, PLAT1 promoted growth under non-stressed conditions. Abiotic stress treatments induced PLAT1 expression and caused expansion of its expression domain. The ABF/ABRE transcription factors, which are positive mediators of abscisic acid signalling, activate PLAT1 promoter activity in transactivation assays and directly bind to the ABRE elements located in this promoter in electrophoretic mobility shift assays. This suggests that PLAT1 represents a novel downstream target of the abscisic acid signalling pathway. Thus, we showed that PLAT1 critically functions as positive regulator of abiotic stress tolerance, but also is involved in regulating plant growth, and thereby assigned a function to this previously uncharacterised PLAT domain protein. The functional data obtained for PLAT1 support that PLAT-plant-stress proteins in general could be promising targets for improving abiotic stress tolerance without yield penalty.

  10. The Cognitive Phenotype in Klinefelter Syndrome: A Review of the Literature Including Genetic and Hormonal Factors

    PubMed Central

    Boada, Richard; Janusz, Jennifer; Hutaff-Lee, Christa; Tartaglia, Nicole

    2011-01-01

    Klinefelter syndrome (KS) or 47,XXY occurs in ∼1 in 650 males. Individuals with KS often present with physical characteristics including tall stature, hypogonadism, and fertility problems. In addition to medical findings, the presence of the extra X chromosome can lead to characteristic cognitive and language deficits of varying severity. While a small, but significant downward shift in mean overall IQ has been reported, the general cognitive abilities of patients with KS are not typically in the intellectual disability range. Most studies support that males with KS have an increased risk of language disorders and reading disabilities. Results of other studies investigating the relationship between verbal and nonverbal/spatial cognitive abilities have been mixed, with differing results based on the age and ascertainment method of the cohort studied. Executive function deficits have been identified in children and adults with KS, however, the research in this area is limited and further investigation of the neuropsychological profile is needed. In this article, we review the strengths and weaknesses of previous cognitive and neuropsychological studies in males with KS in childhood and adulthood, provide historical perspective of these studies, and review what is known about how hormonal and genetic factors influence cognitive features in 47,XXY/KS. PMID:20014369

  11. Biological Networks Underlying Abiotic Stress Tolerance in Temperate Crops—A Proteomic Perspective

    PubMed Central

    Kosová, Klára; Vítámvás, Pavel; Urban, Milan Oldřich; Klíma, Miroslav; Roy, Amitava; Prášil, Ilja Tom

    2015-01-01

    Abiotic stress factors, especially low temperatures, drought, and salinity, represent the major constraints limiting agricultural production in temperate climate. Under the conditions of global climate change, the risk of damaging effects of abiotic stresses on crop production increases. Plant stress response represents an active process aimed at an establishment of novel homeostasis under altered environmental conditions. Proteins play a crucial role in plant stress response since they are directly involved in shaping the final phenotype. In the review, results of proteomic studies focused on stress response of major crops grown in temperate climate including cereals: common wheat (Triticum aestivum), durum wheat (Triticum durum), barley (Hordeum vulgare), maize (Zea mays); leguminous plants: alfalfa (Medicago sativa), soybean (Glycine max), common bean (Phaseolus vulgaris), pea (Pisum sativum); oilseed rape (Brassica napus); potato (Solanum tuberosum); tobacco (Nicotiana tabaccum); tomato (Lycopersicon esculentum); and others, to a wide range of abiotic stresses (cold, drought, salinity, heat, imbalances in mineral nutrition and heavy metals) are summarized. The dynamics of changes in various protein functional groups including signaling and regulatory proteins, transcription factors, proteins involved in protein metabolism, amino acid metabolism, metabolism of several stress-related compounds, proteins with chaperone and protective functions as well as structural proteins (cell wall components, cytoskeleton) are briefly overviewed. Attention is paid to the differences found between differentially tolerant genotypes. In addition, proteomic studies aimed at proteomic investigation of multiple stress factors are discussed. In conclusion, contribution of proteomic studies to understanding the complexity of crop response to abiotic stresses as well as possibilities to identify and utilize protein markers in crop breeding processes are discussed. PMID:26340626

  12. An omics approach to understand the plant abiotic stress.

    PubMed

    Debnath, Mousumi; Pandey, Mukeshwar; Bisen, P S

    2011-11-01

    Abiotic stress can lead to changes in development, productivity, and severe stress and may even threaten survival of plants. Several environmental stresses cause drastic changes in the growth, physiology, and metabolism of plants leading to the increased accumulation of secondary metabolites. As medicinal plants are important sources of drugs, steps are taken to understand the effect of stress on the physiology, biochemistry, genomic, proteomic, and metabolic levels. The molecular responses of plants to abiotic stress are often considered as a complex process. They are mainly based on the modulation of transcriptional activity of stress-related genes. Many genes have been induced under stress conditions. The products of stress-inducible genes protecting against these stresses includes the enzymes responsible for the synthesis of various osmoprotectants. Genetic engineering of tolerance to abiotic stresses help in molecular understanding of pathways induced in response to one or more of the abiotic stresses. Systems biology and virtual experiments allow visualizing and understanding how plants work to overcome abiotic stress. This review discusses the omic approach to understand the plant response to abiotic stress with special emphasis on medicinal plant.

  13. Analytical expressions for the gate utilization factors of passive multiplicity counters including signal build-up

    SciTech Connect

    Croft, Stephen; Evans, Louise G; Schear, Melissa A

    2010-01-01

    In the realm of nuclear safeguards, passive neutron multiplicity counting using shift register pulse train analysis to nondestructively quantify Pu in product materials is a familiar and widely applied technique. The approach most commonly taken is to construct a neutron detector consisting of {sup 3}He filled cylindrical proportional counters embedded in a high density polyethylene moderator. Fast neutrons from the item enter the moderator and are quickly slowed down, on timescales of the order of 1-2 {micro}s, creating a thermal population which then persists typically for several 10's {micro}s and is sampled by the {sup 3}He detectors. Because the initial transient is of comparatively short duration it has been traditional to treat it as instantaneous and furthermore to approximate the subsequent capture time distribution as exponential in shape. With these approximations simple expressions for the various Gate Utilization Factors (GUFs) can be obtained. These factors represent the proportion of time correlated events i.e. Doubles and Triples signal present in the pulse train that is detected by the coincidence gate structure chosen (predelay and gate width settings of the multiplicity shift register). More complicated expressions can be derived by generalizing the capture time distribution to multiple time components or harmonics typically present in real systems. When it comes to applying passive neutron multiplicity methods to extremely intense (i.e. high emission rate and highly multiplying) neutron sources there is a drive to use detector types with very fast response characteristics in order to cope with the high rates. In addition to short pulse width, detectors with a short capture time profile are also desirable so that a short coincidence gate width can be set in order to reduce the chance or Accidental coincidence signal. In extreme cases, such as might be realized using boron loaded scintillators, the dieaway time may be so short that the build

  14. Transcriptome analysis reveals crosstalk of responsive genes to multiple abiotic stresses in cotton (Gossypium hirsutum L.).

    PubMed

    Zhu, Ya-Na; Shi, Dong-Qiao; Ruan, Meng-Bin; Zhang, Li-Li; Meng, Zhao-Hong; Liu, Jie; Yang, Wei-Cai

    2013-01-01

    Abiotic stress is a major environmental factor that limits cotton growth and yield, moreover, this problem has become more and more serious recently, as multiple stresses often occur simultaneously due to the global climate change and environmental pollution. In this study, we sought to identify genes involved in diverse stresses including abscisic acid (ABA), cold, drought, salinity and alkalinity by comparative microarray analysis. Our result showed that 5790, 3067, 5608, 778 and 6148 transcripts, were differentially expressed in cotton seedlings under treatment of ABA (1 μM ABA), cold (4°C), drought (200 mM mannitol), salinity (200 mM NaCl) and alkalinity (pH=11) respectively. Among the induced or suppressed genes, 126 transcripts were shared by all of the five kinds of abiotic stresses, with 64 up-regulated and 62 down-regulated. These common members are grouped as stress signal transduction, transcription factors (TFs), stress response/defense proteins, metabolism, transport facilitation, as well as cell wall/structure, according to the function annotation. We also noticed that large proportion of significant differentially expressed genes specifically regulated in response to different stress. Nine of the common transcripts of multiple stresses were selected for further validation with quantitative real time RT-PCR (qRT-PCR). Furthermore, several well characterized TF families, for example, WRKY, MYB, NAC, AP2/ERF and zinc finger were shown to be involved in different stresses. As an original report using comparative microarray to analyze transcriptome of cotton under five abiotic stresses, valuable information about functional genes and related pathways of anti-stress, and/or stress tolerance in cotton seedlings was unveiled in our result. Besides this, some important common factors were focused for detailed identification and characterization. According to our analysis, it suggested that there was crosstalk of responsive genes or pathways to multiple

  15. Biotic and Abiotic Factors Controlling Respiration Rates of Above- and Belowground Woody Debris of Fagus crenata and Quercus crispula in Japan.

    PubMed

    Jomura, Mayuko; Akashi, Yuhei; Itoh, Hiromu; Yuki, Risa; Sakai, Yoshimi; Maruyama, Yutaka

    2015-01-01

    As a large, long-term pool and source of carbon and nutrients, woody litter is an important component of forest ecosystems. The objective of this study was to estimate the effect of the factors that regulate the rate of decomposition of coarse and fine woody debris (CFWD) of dominant tree species in a cool-temperate forest in Japan. Respiration rates of dead stems, branches, and coarse and fine roots of Fagus crenata and Quercus crispula felled 4 years prior obtained in situ ranged from 20.9 to 500.1 mg CO2 [kg dry wood](-1) h(-1) in a one-time measurement in summer. Respiration rate had a significant negative relationship with diameter; in particular, that of a sample of Q. crispula with a diameter of >15 cm and substantial heartwood was low. It also had a significant positive relationship with moisture content. The explanatory variables diameter, [N], wood density, and moisture content were interrelated. The most parsimonious path model showed 14 significant correlations among 8 factors and respiration. Diameter and [C] had large negative direct effects on CFWD respiration rate, and moisture content and species had medium positive direct effects. [N] and temperature did not have direct or indirect effects, and position and wood density had indirect effects. The model revealed some interrelationships between controlling factors. We discussed the influence of the direct effects of explanatory variables and the influence especially of species and position. We speculate that the small R2 value of the most parsimonious model was probably due to the omission of microbial biomass and activity. These direct and indirect effects and interrelationships between explanatory variables could be used to develop a process-based CFWD decomposition model.

  16. Biotic and Abiotic Factors Controlling Respiration Rates of Above- and Belowground Woody Debris of Fagus crenata and Quercus crispula in Japan

    PubMed Central

    Jomura, Mayuko; Akashi, Yuhei; Itoh, Hiromu; Yuki, Risa; Sakai, Yoshimi; Maruyama, Yutaka

    2015-01-01

    As a large, long-term pool and source of carbon and nutrients, woody litter is an important component of forest ecosystems. The objective of this study was to estimate the effect of the factors that regulate the rate of decomposition of coarse and fine woody debris (CFWD) of dominant tree species in a cool-temperate forest in Japan. Respiration rates of dead stems, branches, and coarse and fine roots of Fagus crenata and Quercus crispula felled 4 years prior obtained in situ ranged from 20.9 to 500.1 mg CO2 [kg dry wood]–1 h–1 in a one-time measurement in summer. Respiration rate had a significant negative relationship with diameter; in particular, that of a sample of Q. crispula with a diameter of >15 cm and substantial heartwood was low. It also had a significant positive relationship with moisture content. The explanatory variables diameter, [N], wood density, and moisture content were interrelated. The most parsimonious path model showed 14 significant correlations among 8 factors and respiration. Diameter and [C] had large negative direct effects on CFWD respiration rate, and moisture content and species had medium positive direct effects. [N] and temperature did not have direct or indirect effects, and position and wood density had indirect effects. The model revealed some interrelationships between controlling factors. We discussed the influence of the direct effects of explanatory variables and the influence especially of species and position. We speculate that the small R2 value of the most parsimonious model was probably due to the omission of microbial biomass and activity. These direct and indirect effects and interrelationships between explanatory variables could be used to develop a process-based CFWD decomposition model. PMID:26658727

  17. The AaDREB1 Transcription Factor from the Cold-Tolerant Plant Adonis amurensis Enhances Abiotic Stress Tolerance in Transgenic Plant.

    PubMed

    Zong, Jun-Mei; Li, Xiao-Wei; Zhou, Yuan-Hang; Wang, Fa-Wei; Wang, Nan; Dong, Yuan-Yuan; Yuan, Yan-Xi; Chen, Huan; Liu, Xiu-Ming; Yao, Na; Li, Hai-Yan

    2016-04-22

    Dehydration-responsive element binding (DREB) transcription factors (TFs) play important roles in the regulation of plant resistance to environmental stresses and can specifically bind to dehydration-responsive element/C-repeat element (DRE/CRT) proteins (G/ACCGAC) and activate expression of many stress-inducible genes. Here, we cloned and characterized a novel gene (AaDREB1) encoding the DREB1 transcription factor from the cold-tolerant plant Adonis amurensis. Quantitative real-time (qRT)-PCR results indicated that AaDREB1 expression was induced by salt, drought, cold stress, and abscisic acid application. A yeast one-hybrid assay demonstrated that AaDREB1 encodes a transcription activator and specifically binds to DRE/CRT. Furthermore, transgenic Arabidopsis and rice harboring AaDREB1 showed enhanced tolerance to salt, drought, and low temperature. These results indicated that AaDREB1 might be useful in genetic engineering to improve plant stress tolerance.

  18. The AaDREB1 Transcription Factor from the Cold-Tolerant Plant Adonis amurensis Enhances Abiotic Stress Tolerance in Transgenic Plant

    PubMed Central

    Zong, Jun-Mei; Li, Xiao-Wei; Zhou, Yuan-Hang; Wang, Fa-Wei; Wang, Nan; Dong, Yuan-Yuan; Yuan, Yan-Xi; Chen, Huan; Liu, Xiu-Ming; Yao, Na; Li, Hai-Yan

    2016-01-01

    Dehydration-responsive element binding (DREB) transcription factors (TFs) play important roles in the regulation of plant resistance to environmental stresses and can specifically bind to dehydration-responsive element/C-repeat element (DRE/CRT) proteins (G/ACCGAC) and activate expression of many stress-inducible genes. Here, we cloned and characterized a novel gene (AaDREB1) encoding the DREB1 transcription factor from the cold-tolerant plant Adonis amurensis. Quantitative real-time (qRT)-PCR results indicated that AaDREB1 expression was induced by salt, drought, cold stress, and abscisic acid application. A yeast one-hybrid assay demonstrated that AaDREB1 encodes a transcription activator and specifically binds to DRE/CRT. Furthermore, transgenic Arabidopsis and rice harboring AaDREB1 showed enhanced tolerance to salt, drought, and low temperature. These results indicated that AaDREB1 might be useful in genetic engineering to improve plant stress tolerance. PMID:27110776

  19. Functional Analysis of the Maize C-Repeat/DRE Motif-Binding Transcription Factor CBF3 Promoter in Response to Abiotic Stress

    PubMed Central

    Liu, Jinliang; Wang, Fengting; Yu, Gang; Zhang, Xianghui; Jia, Chengguo; Qin, Jianchun; Pan, Hongyu

    2015-01-01

    The ZmCBF3 gene is a member of AP2/ERF transcription factor family, which is a large family of plant-specific transcription factors that share a well-conserved DNA-binding domain. To understand the regulatory mechanism of ZmCBF3 gene expression, we isolated and characterized the ZmCBF3 promoter (PZmCBF3). Three deletion fragments of PZmCBF3 were generated, C1–C3, from the translation start codon at position −1079, −638, and −234, and fused to the GUS reporter gene. Each deletion construct was analyzed by Agrobacterium-mediated stable transformation and expression in Arabidopsis thaliana. GUS expression assays indicated that the PZmCBF3 exhibited root-specific expression activity. A 234-bp fragment upstream of the ZmCBF3 gene conferred a high level of GUS activity in Arabidopsis. Some cis-acting elements involved in the down-regulation of gene expression were detected in the promoter, encompassing positions −1079 to −234. PZmCBF3 was activated by cold stress. The MYCCONSENSUSAT elements (CANNTG) were responsible for the ability of PZmCBF3 to respond to cold stress. The results of the present study suggest that PZmCBF3 might play a role in cold tolerance in maize. PMID:26030672

  20. ROS-mediated abiotic stress-induced programmed cell death in plants

    PubMed Central

    Petrov, Veselin; Hille, Jacques; Mueller-Roeber, Bernd; Gechev, Tsanko S.

    2015-01-01

    During the course of their ontogenesis plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD). This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS) which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process. PMID:25741354

  1. Accurate expressions for solar cell fill factors including series and shunt resistances

    NASA Astrophysics Data System (ADS)

    Green, Martin A.

    2016-02-01

    Together with open-circuit voltage and short-circuit current, fill factor is a key solar cell parameter. In their classic paper on limiting efficiency, Shockley and Queisser first investigated this factor's analytical properties showing, for ideal cells, it could be expressed implicitly in terms of the maximum power point voltage. Subsequently, fill factors usually have been calculated iteratively from such implicit expressions or from analytical approximations. In the absence of detrimental series and shunt resistances, analytical fill factor expressions have recently been published in terms of the Lambert W function available in most mathematical computing software. Using a recently identified perturbative relationship, exact expressions in terms of this function are derived in technically interesting cases when both series and shunt resistances are present but have limited impact, allowing a better understanding of their effect individually and in combination. Approximate expressions for arbitrary shunt and series resistances are then deduced, which are significantly more accurate than any previously published. A method based on the insights developed is also reported for deducing one-diode fits to experimental data.

  2. Latina Resilience in Higher Education: Contributing Factors Including Seasonal Farmworker Experiences

    ERIC Educational Resources Information Center

    Graff, Cristina Santamaria; McCain, Terrence; Gomez-Vilchis, Veronica

    2013-01-01

    Many Latina students overcome multiple obstacles to earn university degrees. Five married Latina women with children and seasonal farmworker backgrounds are the focus of this study which is analyzed through resiliency theory to understand factors contributing to their academic resilience. Variables connected to academic success are explored and…

  3. Establishment of non-native plant species after wildfires: Effects of fuel treatments, abiotic and biotic factors, and post-fire grass seeding treatments

    USGS Publications Warehouse

    Hunter, M.E.; Omi, Philip N.; Martinson, E.J.; Chong, G.W.

    2006-01-01

    Establishment and spread of non-native species following wildfires can pose threats to long-term native plant recovery. Factors such as disturbance severity, resource availability, and propagule pressure may influence where non-native species establish in burned areas. In addition, pre- and post-fire management activities may influence the likelihood of non-native species establishment. In the present study we examine the establishment of non-native species after wildfires in relation to native species richness, fire severity, dominant native plant cover, resource availability, and pre- and post-fire management actions (fuel treatments and post-fire rehabilitation treatments). We used an information-theoretic approach to compare alternative hypotheses. We analysed post-fire effects at multiple scales at three wildfires in Colorado and New Mexico. For large and small spatial scales at all fires, fire severity was the most consistent predictor of non-native species cover. Non-native species cover was also correlated with high native species richness, low native dominant species cover, and high seeded grass cover. There was a positive, but non-significant, association of non-native species with fuel-treated areas at one wildfire. While there may be some potential for fuels treatments to promote non-native species establishment, wildfire and post-fire seeding treatments seem to have a larger impact on non-native species. ?? IAWF 2006.

  4. Transcription factors relevant to auxin signalling coordinate broad-spectrum metabolic shifts including sulphur metabolism

    PubMed Central

    Falkenberg, Bettina; Witt, Isabell; Zanor, Maria Inés; Steinhauser, Dirk; Mueller-Roeber, Bernd; Hesse, Holger; Hoefgen, Rainer

    2008-01-01

    A systems approach has previously been used to follow the response behaviour of Arabidopsis thaliana plants upon sulphur limitation. A response network was reconstructed from a time series of transcript and metabolite profiles, integrating complex metabolic and transcript data in order to investigate a potential causal relationship. The resulting scale-free network allowed potential transcriptional regulators of sulphur metabolism to be identified. Here, three sulphur-starvation responsive transcription factors, IAA13, IAA28, and ARF-2 (ARF1-Binding Protein), all of which are related to auxin signalling, were selected for further investigation. IAA28 overexpressing and knock-down lines showed no major morphological changes, whereas IAA13- and ARF1-BP-overexpressing plants grew more slowly than the wild type. Steady-state metabolite levels and expression of pathway-relevant genes were monitored under normal and sulphate-depleted conditions. For all lines, changes in transcript and metabolite levels were observed, yet none of these changes could exclusively be linked to sulphur stress. Instead, up- or down-regulation of the transcription factors caused metabolic changes which in turn affected sulphur metabolism. Auxin-relevant transcription factors are thus part of a complex response pattern to nutrient starvation that serve as coordinators of the metabolic shifts driving sulphur homeostasis rather then as direct effectors of the sulphate assimilation pathway. This study provides the first evidence ever presented that correlates auxin-related transcriptional regulators with primary plant metabolism. PMID:18596113

  5. Experiences with new European standards for calculation of flanged joints including necessary gasket factors

    SciTech Connect

    Bartonicek, J.; Kockelmann, H.; Schoeckle, F.

    1996-12-01

    The correct function of a flanged joint in a given construction (flanges, bolts) and with given loads (pressure, temperature, additional forces) depends on the following: (1) choice of the gasket for the operation environment; (2) determination of the gasket stress for assembly conditions; and (3) gasket stress in operation, i.e., the conditions when leakage has to be minimized. For the correct choice of a gasket it is necessary to have gasket factors available, as given by DIN 28090 (Sept. 95) together with the test procedures. These gasket factors determine the tightening characteristics as well as the deformation capability of the gaskets. Furthermore, these gasket factors must be available for use in calculations. On the basis of calculations a stress analysis (i.e. a limitation of the stresses in flanges and bolts) must be possible as well as the determination of the bolt forces for the assembly state and of the gasket stress for operating conditions. This is one of the goals of the standard pr DIN EN 1591. The paper first introduces the actual European standards. Calculations are reviewed using test data from special test rigs and from real flanged joints. The calculations were made according to DIN 2505 (initial German standard for flanged joints) and pr DIN EN 1591. Additionally, 2D and 3D Finite Element analysis calculations were performed.

  6. Transcription factors relevant to auxin signalling coordinate broad-spectrum metabolic shifts including sulphur metabolism.

    PubMed

    Falkenberg, Bettina; Witt, Isabell; Zanor, Maria Inés; Steinhauser, Dirk; Mueller-Roeber, Bernd; Hesse, Holger; Hoefgen, Rainer

    2008-01-01

    A systems approach has previously been used to follow the response behaviour of Arabidopsis thaliana plants upon sulphur limitation. A response network was reconstructed from a time series of transcript and metabolite profiles, integrating complex metabolic and transcript data in order to investigate a potential causal relationship. The resulting scale-free network allowed potential transcriptional regulators of sulphur metabolism to be identified. Here, three sulphur-starvation responsive transcription factors, IAA13, IAA28, and ARF-2 (ARF1-Binding Protein), all of which are related to auxin signalling, were selected for further investigation. IAA28 overexpressing and knock-down lines showed no major morphological changes, whereas IAA13- and ARF1-BP-overexpressing plants grew more slowly than the wild type. Steady-state metabolite levels and expression of pathway-relevant genes were monitored under normal and sulphate-depleted conditions. For all lines, changes in transcript and metabolite levels were observed, yet none of these changes could exclusively be linked to sulphur stress. Instead, up- or down-regulation of the transcription factors caused metabolic changes which in turn affected sulphur metabolism. Auxin-relevant transcription factors are thus part of a complex response pattern to nutrient starvation that serve as coordinators of the metabolic shifts driving sulphur homeostasis rather then as direct effectors of the sulphate assimilation pathway. This study provides the first evidence ever presented that correlates auxin-related transcriptional regulators with primary plant metabolism.

  7. ROS Regulation During Abiotic Stress Responses in Crop Plants.

    PubMed

    You, Jun; Chan, Zhulong

    2015-01-01

    Abiotic stresses such as drought, cold, salt and heat cause reduction of plant growth and loss of crop yield worldwide. Reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide anions (O2 (•-)), hydroxyl radical (OH•) and singlet oxygen ((1)O2) are by-products of physiological metabolisms, and are precisely controlled by enzymatic and non-enzymatic antioxidant defense systems. ROS are significantly accumulated under abiotic stress conditions, which cause oxidative damage and eventually resulting in cell death. Recently, ROS have been also recognized as key players in the complex signaling network of plants stress responses. The involvement of ROS in signal transduction implies that there must be coordinated function of regulation networks to maintain ROS at non-toxic levels in a delicate balancing act between ROS production, involving ROS generating enzymes and the unavoidable production of ROS during basic cellular metabolism, and ROS-scavenging pathways. Increasing evidence showed that ROS play crucial roles in abiotic stress responses of crop plants for the activation of stress-response and defense pathways. More importantly, manipulating ROS levels provides an opportunity to enhance stress tolerances of crop plants under a variety of unfavorable environmental conditions. This review presents an overview of current knowledge about homeostasis regulation of ROS in crop plants. In particular, we summarize the essential proteins that are involved in abiotic stress tolerance of crop plants through ROS regulation. Finally, the challenges toward the improvement of abiotic stress tolerance through ROS regulation in crops are discussed.

  8. ROS Regulation During Abiotic Stress Responses in Crop Plants

    PubMed Central

    You, Jun; Chan, Zhulong

    2015-01-01

    Abiotic stresses such as drought, cold, salt and heat cause reduction of plant growth and loss of crop yield worldwide. Reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide anions (O2•-), hydroxyl radical (OH•) and singlet oxygen (1O2) are by-products of physiological metabolisms, and are precisely controlled by enzymatic and non-enzymatic antioxidant defense systems. ROS are significantly accumulated under abiotic stress conditions, which cause oxidative damage and eventually resulting in cell death. Recently, ROS have been also recognized as key players in the complex signaling network of plants stress responses. The involvement of ROS in signal transduction implies that there must be coordinated function of regulation networks to maintain ROS at non-toxic levels in a delicate balancing act between ROS production, involving ROS generating enzymes and the unavoidable production of ROS during basic cellular metabolism, and ROS-scavenging pathways. Increasing evidence showed that ROS play crucial roles in abiotic stress responses of crop plants for the activation of stress-response and defense pathways. More importantly, manipulating ROS levels provides an opportunity to enhance stress tolerances of crop plants under a variety of unfavorable environmental conditions. This review presents an overview of current knowledge about homeostasis regulation of ROS in crop plants. In particular, we summarize the essential proteins that are involved in abiotic stress tolerance of crop plants through ROS regulation. Finally, the challenges toward the improvement of abiotic stress tolerance through ROS regulation in crops are discussed. PMID:26697045

  9. Abiotic regulation: a common way for proteins to modulate their functions.

    PubMed

    Zou, Zhi; Fu, Xinmiao

    2015-01-01

    Modulation of protein intrinsic activity in cells is generally carried out via a combination of four common ways, i.e., allosteric regulation, covalent modification, proteolytic cleavage and association of other regulatory proteins. Accumulated evidence indicate that changes of certain abiotic factors (e.g., temperature, pH, light and mechanical force) within or outside the cells directly influence protein structure and thus profoundly modulate the functions of a wide range of proteins, termed as abiotic regulatory proteins (e.g., heat shock factor, small heat shock protein, hemoglobin, zymogen, integrin, rhodopsin). Such abiotic regulation apparently differs from the four classic ways in perceiving and response to the signals. Importantly, it enables cells to directly and also immediately response to extracellular stimuli, thus facilitating the ability of organisms to resist against and adapt to the abiotic stress and thereby playing crucial roles in life evolution. Altogether, abiotic regulation may be considered as a common way for proteins to modulate their functions.

  10. Including social factors in the analysis of reminiscence in elderly individuals.

    PubMed

    Lamme, S; Baars, J

    1993-01-01

    Developmental psychologists have studied reminiscence in elderly individuals using widely varied conceptions of adult development. Determinist psychologists conceived of reminiscent behavior in elderly individuals as constituting the last phase in normal development. Contextualist psychologists have pointed to the historical and cultural relativity of adult development, and highlighted the variation in elderly persons with respect to reminiscent behavior. However, they do not fully acknowledge the role the environment plays in establishing reminiscent behavior in elderly people. Therefore, sociological life course theory should be included in the analyses and interpretation of this behavior.

  11. Starch as a determinant of plant fitness under abiotic stress.

    PubMed

    Thalmann, Matthias; Santelia, Diana

    2017-03-09

    I. II. III. IV. V. VI. References SUMMARY: Abiotic stresses, such as drought, high salinity and extreme temperatures, pose one of the most important constraints to plant growth and productivity in many regions of the world. A number of investigations have shown that plants, including several important crops, remobilize their starch reserve to release energy, sugars and derived metabolites to help mitigate the stress. This is an essential process for plant fitness with important implications for plant productivity under challenging environmental conditions. In this Tansley insight, we evaluate the current literature on starch metabolism in response to abiotic stresses, and discuss the key enzymes involved and how they are regulated.

  12. ‘LONESOME TOWN’? IS LONELINESS ASSOCIATED WITH THE RESIDENTIAL ENVIRONMENT, INCLUDING HOUSING AND NEIGHBORHOOD FACTORS?

    PubMed Central

    Whitley, Elise; Tannahill, Carol; Ellaway, Anne

    2015-01-01

    This article considers whether feelings of loneliness are associated with aspects of the home and neighborhood of residence. Multinominal logistic regression models were used to explore associations between residential environment and loneliness in 4,000 residents across deprived areas of Glasgow. People who rated their neighborhood environment of higher quality and who used more local amenities were less likely to report loneliness. Respondents who knew more people within the local area were less likely to report loneliness. Those who reported more antisocial behavior problems, who had a weak perception of collective efficacy, and who felt unsafe walking alone at nighttime were more likely to report loneliness. Length of residence and dwelling type were not associated with reported loneliness. The findings indicate the potential importance of several dimensions of the neighborhood physical, service, and social environment, including aspects of both quality and trust, in protecting against or reducing loneliness in deprived areas. PMID:26740728

  13. Simultaneous optimization of monolayer formation factors, including temperature, to significantly improve nucleic acid hybridization efficiency on gold substrates.

    PubMed

    Pris, Andrew D; Ostrowski, Sara G; Garaas, Sarah D

    2010-04-20

    Past literature investigations have optimized various single factors used in the formation of thiolated, single stranded DNA (ss-DNA) monolayers on gold. In this study a more comprehensive approach is taken, where a design of experiment (DOE) is employed to simultaneously optimize all of the factors involved in construction of the capture monolayer used in a fluorescence-based hybridization assay. Statistical analysis of the fluorescent intensities resulting from the DOE provides empirical evidence for the importance and the optimal levels of traditional and novel factors included in this investigation. We report on the statistical importance of a novel factor, temperature of the system during monolayer formation of the capture molecule and lateral spacer molecule, and how proper usage of this temperature factor increased the hybridization signal 50%. An initial theory of how the physical factor of heat is mechanistically supplementing the function of the lateral spacer molecule is provided.

  14. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants

    PubMed Central

    Hasanuzzaman, Mirza; Nahar, Kamrun; Hossain, Md. Shahadat; Mahmud, Jubayer Al; Rahman, Anisur; Inafuku, Masashi; Oku, Hirosuke; Fujita, Masayuki

    2017-01-01

    Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS). Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG), which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I) and glyoxalase II (Gly II), and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III), has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH) acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated action of

  15. Abiotic stresses affect Trichoderma harzianum T39-induced resistance to downy mildew in grapevine.

    PubMed

    Roatti, Benedetta; Perazzolli, Michele; Gessler, Cesare; Pertot, Ilaria

    2013-12-01

    Enhancement of plant defense through the application of resistance inducers seems a promising alternative to chemical fungicides for controlling crop diseases but the efficacy can be affected by abiotic factors in the field. Plants respond to abiotic stresses with hormonal signals that may interfere with the mechanisms of induced systemic resistance (ISR) to pathogens. In this study, we exposed grapevines to heat, drought, or both to investigate the effects of abiotic stresses on grapevine resistance induced by Trichoderma harzianum T39 (T39) to downy mildew. Whereas the efficacy of T39-induced resistance was not affected by exposure to heat or drought, it was significantly reduced by combined abiotic stresses. Decrease of leaf water potential and upregulation of heat-stress markers confirmed that plants reacted to abiotic stresses. Basal expression of defense-related genes and their upregulation during T39-induced resistance were attenuated by abiotic stresses, in agreement with the reduced efficacy of T39. The evidence reported here suggests that exposure of crops to abiotic stress should be carefully considered to optimize the use of resistance inducers, especially in view of future global climate changes. Expression analysis of ISR marker genes could be helpful to identify when plants are responding to abiotic stresses, in order to optimize treatments with resistance inducers in field.

  16. Integrating omic approaches for abiotic stress tolerance in soybean

    PubMed Central

    Deshmukh, Rupesh; Sonah, Humira; Patil, Gunvant; Chen, Wei; Prince, Silvas; Mutava, Raymond; Vuong, Tri; Valliyodan, Babu; Nguyen, Henry T.

    2014-01-01

    Soybean production is greatly influenced by abiotic stresses imposed by environmental factors such as drought, water submergence, salt, and heavy metals. A thorough understanding of plant response to abiotic stress at the molecular level is a prerequisite for its effective management. The molecular mechanism of stress tolerance is complex and requires information at the omic level to understand it effectively. In this regard, enormous progress has been made in the omics field in the areas of genomics, transcriptomics, and proteomics. The emerging field of ionomics is also being employed for investigating abiotic stress tolerance in soybean. Omic approaches generate a huge amount of data, and adequate advancements in computational tools have been achieved for effective analysis. However, the integration of omic-scale information to address complex genetics and physiological questions is still a challenge. In this review, we have described advances in omic tools in the view of conventional and modern approaches being used to dissect abiotic stress tolerance in soybean. Emphasis was given to approaches such as quantitative trait loci (QTL) mapping, genome-wide association studies (GWAS), and genomic selection (GS). Comparative genomics and candidate gene approaches are also discussed considering identification of potential genomic loci, genes, and biochemical pathways involved in stress tolerance mechanism in soybean. This review also provides a comprehensive catalog of available online omic resources for soybean and its effective utilization. We have also addressed the significance of phenomics in the integrated approaches and recognized high-throughput multi-dimensional phenotyping as a major limiting factor for the improvement of abiotic stress tolerance in soybean. PMID:24917870

  17. The Benefits of Including Clinical Factors in Rectal Normal Tissue Complication Probability Modeling After Radiotherapy for Prostate Cancer

    SciTech Connect

    Defraene, Gilles; Van den Bergh, Laura; Al-Mamgani, Abrahim; Haustermans, Karin; Heemsbergen, Wilma; Van den Heuvel, Frank; Lebesque, Joos V.

    2012-03-01

    Purpose: To study the impact of clinical predisposing factors on rectal normal tissue complication probability modeling using the updated results of the Dutch prostate dose-escalation trial. Methods and Materials: Toxicity data of 512 patients (conformally treated to 68 Gy [n = 284] and 78 Gy [n = 228]) with complete follow-up at 3 years after radiotherapy were studied. Scored end points were rectal bleeding, high stool frequency, and fecal incontinence. Two traditional dose-based models (Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) and a logistic model were fitted using a maximum likelihood approach. Furthermore, these model fits were improved by including the most significant clinical factors. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminating ability of all fits. Results: Including clinical factors significantly increased the predictive power of the models for all end points. In the optimal LKB, RS, and logistic models for rectal bleeding and fecal incontinence, the first significant (p = 0.011-0.013) clinical factor was 'previous abdominal surgery.' As second significant (p = 0.012-0.016) factor, 'cardiac history' was included in all three rectal bleeding fits, whereas including 'diabetes' was significant (p = 0.039-0.048) in fecal incontinence modeling but only in the LKB and logistic models. High stool frequency fits only benefitted significantly (p = 0.003-0.006) from the inclusion of the baseline toxicity score. For all models rectal bleeding fits had the highest AUC (0.77) where it was 0.63 and 0.68 for high stool frequency and fecal incontinence, respectively. LKB and logistic model fits resulted in similar values for the volume parameter. The steepness parameter was somewhat higher in the logistic model, also resulting in a slightly lower D{sub 50}. Anal wall DVHs were used for fecal incontinence, whereas anorectal wall dose best described the other two endpoints. Conclusions: Comparable

  18. Abiotic degradation of plastic films

    NASA Astrophysics Data System (ADS)

    Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

    2017-01-01

    Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

  19. Genome-wide characterization and expression profiling of the NAC genes under abiotic stresses in Cucumis sativus.

    PubMed

    Zhang, Xiao Meng; Yu, Hong Jun; Sun, Chao; Deng, Jie; Zhang, Xue; Liu, Peng; Li, Yun Yun; Li, Qiang; Jiang, Wei Jie

    2017-04-01

    The NAC (standing for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF] and cup-shaped cotyledon [CUC]) proteins pertain to one of the plant-specific transcription factor families that play important roles in plant development, abiotic stress resistance and signalling transduction. In the present study, the genomic features of the NAC genes in cucumber were analysed in depth using in silico tools. To reveal a tissue-specific, abiotic stress and hormone-responsive expression profile of CsNAC genes, RT-qPCR was performed under different treatments. Phylogenetic analyses and genome-wide annotation indicated that 82 high-confidence CsNAC genes were clustered into 13 sub-groups with uneven distribution in the cucumber genome. Furthermore, the CsNAC genes exhibited different tissue-specific expression patterns in 10 tissues under normal growth conditions, while 13 (16%) and 28 (34%) genes displayed preferential expression in roots and flowers, respectively. Moreover, CsNAC genes were more sensitive to salinity than other stresses; however, their responses were relatively rapid and transient to nutrition deprivation. Several CsNAC genes, including CsNAC35, which is an orthologue of the known stress-responsive Arabidopsis RD26, were identified as highly responsive to abiotic stresses and hormones. Overall, our findings revealed the genomic landscape and expression profiling of the CsNAC genes in response to multiple stresses and hormones, offering clues for further function analyses and molecular breeding.

  20. Abiotic stress in crops: candidate genes, osmolytes, polyamines and biotechnological intervention

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural production and quality are adversely affected by various abiotic stresses including water deficit conditions (drought), salinity, extreme temperatures (heat, cold), light intensities beyond those saturating for photosynthesis and radiation (UVB,C). This is exacerbated when such exposure...

  1. Mesenchymal stem cell therapy ameliorates diabetic nephropathy via the paracrine effect of renal trophic factors including exosomes

    PubMed Central

    Nagaishi, Kanna; Mizue, Yuka; Chikenji, Takako; Otani, Miho; Nakano, Masako; Konari, Naoto; Fujimiya, Mineko

    2016-01-01

    Bone marrow-derived mesenchymal stem cells (MSCs) have contributed to the improvement of diabetic nephropathy (DN); however, the actual mediator of this effect and its role has not been characterized thoroughly. We investigated the effects of MSC therapy on DN, focusing on the paracrine effect of renal trophic factors, including exosomes secreted by MSCs. MSCs and MSC-conditioned medium (MSC-CM) as renal trophic factors were administered in parallel to high-fat diet (HFD)-induced type 2 diabetic mice and streptozotocin (STZ)-induced insulin-deficient diabetic mice. Both therapies showed approximately equivalent curative effects, as each inhibited the exacerbation of albuminuria. They also suppressed the excessive infiltration of BMDCs into the kidney by regulating the expression of the adhesion molecule ICAM-1. Proinflammatory cytokine expression (e.g., TNF-α) and fibrosis in tubular interstitium were inhibited. TGF-β1 expression was down-regulated and tight junction protein expression (e.g., ZO-1) was maintained, which sequentially suppressed the epithelial-to-mesenchymal transition of tubular epithelial cells (TECs). Exosomes purified from MSC-CM exerted an anti-apoptotic effect and protected tight junction structure in TECs. The increase of glomerular mesangium substrate was inhibited in HFD-diabetic mice. MSC therapy is a promising tool to prevent DN via the paracrine effect of renal trophic factors including exosomes due to its multifactorial action. PMID:27721418

  2. Abiotic pyrite formation produces a large Fe isotope fractionation.

    PubMed

    Guilbaud, Romain; Butler, Ian B; Ellam, Rob M

    2011-06-24

    The iron isotope composition of sedimentary pyrite has been proposed as a potential proxy to trace microbial metabolism and the redox evolution of the oceans. We demonstrate that Fe isotope fractionation accompanies abiotic pyrite formation in the absence of Fe(II) redox change. Combined fractionation factors between Fe(II)(aq), mackinawite, and pyrite permit the generation of pyrite with Fe isotope signatures that nearly encapsulate the full range of sedimentary δ(56)Fe(pyrite) recorded in Archean to modern sediments. We propose that Archean negative Fe isotope excursions reflect partial Fe(II)(aq) utilization during abiotic pyrite formation rather than microbial dissimilatory Fe(III) reduction. Late Proterozoic to modern sediments may reflect greater Fe(II)(aq) utilization and variations in source composition.

  3. Biotic and abiotic constraints that facilitate host exclusivity of Gondwanamyces and Ophiostoma on Protea.

    PubMed

    Roets, Francois; Theron, Natalie; Wingfield, Michael J; Dreyer, Léanne L

    2012-01-01

    Estimations of global fungal diversity are hampered by a limited understanding of the forces that dictate host exclusivity in saprobic microfungi. To consider this problem for Gondwanamyces and Ophiostoma found in the flower heads of Protea in South Africa, we determined the role of various factors thought to influence their host exclusivity. Results showed that various biotic and abiotic factors influence the growth and survival of these fungi in vitro. Monitoring temperature and relative humidity (RH) fluctuations within infructescences in vivo revealed considerable microclimatic differences between different Protea spp. Fungal growth and survival at different RH levels experienced in the field suggested that this factor does not play a major role in host exclusivity of these fungi. Maximum temperatures within infructescences and host preferences of the vectors of Gondwanamyces and Ophiostoma appear to play a substantial part in determining colonisation of Protea in general. However, these factors did not explain host exclusivity of specific fungal species towards particular Protea hosts. In contrast, differential growth of fungal species on media containing macerated tissue of Protea showed that Gondwanamyces and Ophiostoma grow best on tissue from their natural hosts. Thus, host chemistry plays a role in host exclusivity of these fungi, although some species grew vigorously on tissue of Protea spp. with which they are not naturally associated. A combination of host chemistry and temperature partially explains host exclusivity, but the relationship for these factors on the tested saprobic microfungi and their hosts is clearly complex and most likely includes combinations of various biotic and abiotic factors including those emerging from this study.

  4. SUMO, a heavyweight player in plant abiotic stress responses.

    PubMed

    Castro, Pedro Humberto; Tavares, Rui Manuel; Bejarano, Eduardo R; Azevedo, Herlânder

    2012-10-01

    Protein post-translational modifications diversify the proteome and install new regulatory levels that are crucial for the maintenance of cellular homeostasis. Over the last decade, the ubiquitin-like modifying peptide small ubiquitin-like modifier (SUMO) has been shown to regulate various nuclear processes, including transcriptional control. In plants, the sumoylation pathway has been significantly implicated in the response to environmental stimuli, including heat, cold, drought, and salt stresses, modulation of abscisic acid and other hormones, and nutrient homeostasis. This review focuses on the emerging importance of SUMO in the abiotic stress response, summarizing the molecular implications of sumoylation and emphasizing how high-throughput approaches aimed at identifying the full set of SUMO targets will greatly enhance our understanding of the SUMO-abiotic stress association.

  5. Reverse engineering: a key component of systems biology to unravel global abiotic stress cross-talk.

    PubMed

    Friedel, Swetlana; Usadel, Björn; von Wirén, Nicolaus; Sreenivasulu, Nese

    2012-01-01

    Understanding the global abiotic stress response is an important stepping stone for the development of universal stress tolerance in plants in the era of climate change. Although co-occurrence of several stress factors (abiotic and biotic) in nature is found to be frequent, current attempts are poor to understand the complex physiological processes impacting plant growth under combinatory factors. In this review article, we discuss the recent advances of reverse engineering approaches that led to seminal discoveries of key candidate regulatory genes involved in cross-talk of abiotic stress responses and summarized the available tools of reverse engineering and its relevant application. Among the universally induced regulators involved in various abiotic stress responses, we highlight the importance of (i) abscisic acid (ABA) and jasmonic acid (JA) hormonal cross-talks and (ii) the central role of WRKY transcription factors (TF), potentially mediating both abiotic and biotic stress responses. Such interactome networks help not only to derive hypotheses but also play a vital role in identifying key regulatory targets and interconnected hormonal responses. To explore the full potential of gene network inference in the area of abiotic stress tolerance, we need to validate hypotheses by implementing time-dependent gene expression data from genetically engineered plants with modulated expression of target genes. We further propose to combine information on gene-by-gene interactions with data from physical interaction platforms such as protein-protein or TF-gene networks.

  6. A bHLH gene from Tamarix hispida improves abiotic stress tolerance by enhancing osmotic potential and decreasing reactive oxygen species accumulation.

    PubMed

    Ji, Xiaoyu; Nie, Xianguang; Liu, Yujia; Zheng, Lei; Zhao, Huimin; Zhang, Bing; Huo, Lin; Wang, Yucheng

    2016-02-01

    Basic helix-loop-helix (bHLH) leucine-zipper transcription factors play important roles in abiotic stress responses. However, their specific roles in abiotic stress tolerance are not fully known. Here, we functionally characterized a bHLH gene, ThbHLH1, from Tamarix hispida in abiotic stress tolerance. ThbHLH1 specifically binds to G-box motif with the sequence of 'CACGTG'. Transiently transfected T. hispida plantlets with transiently overexpressed ThbHLH1 and RNAi-silenced ThbHLH1 were generated for gain- and loss-of-function analysis. Transgenic Arabidopsis thaliana lines overexpressing ThbHLH1 were generated to confirm the gain- and loss-of-function analysis. Overexpression of ThbHLH1 significantly elevates glycine betaine and proline levels, increases Ca(2+) concentration and enhances peroxidase (POD) and superoxide dismutase (SOD) activities to decrease reactive oxygen species (ROS) accumulation. Additionally, ThbHLH1 regulates the expression of the genes including P5CS, BADH, CaM, POD and SOD, to activate the above physiological changes, and also induces the expression of stress tolerance-related genes LEAs and HSPs. These data suggest that ThbHLH1 induces the expression of stress tolerance-related genes to improve abiotic stress tolerance by increasing osmotic potential, improving ROS scavenging capability and enhancing second messenger in stress signaling cascades.

  7. Abiotic mediation of a mutualism drives herbivore abundance.

    PubMed

    Mooney, Emily H; Phillips, Joseph S; Tillberg, Chadwick V; Sandrow, Cheryl; Nelson, Annika S; Mooney, Kailen A

    2016-01-01

    Species abundance is typically determined by the abiotic environment, but the extent to which such effects occur through the mediation of biotic interactions, including mutualisms, is unknown. We explored how light environment (open meadow vs. shaded understory) mediates the abundance and ant tending of the aphid Aphis helianthi feeding on the herb Ligusticum porteri. Yearly surveys consistently found aphids to be more than 17-fold more abundant on open meadow plants than on shaded understory plants. Manipulations demonstrated that this abundance pattern was not due to the direct effects of light environment on aphid performance, or indirectly through host plant quality or the effects of predators. Instead, open meadows had higher ant abundance and per capita rates of aphid tending and, accordingly, ants increased aphid population growth in meadow but not understory environments. The abiotic environment thus drives the abundance of this herbivore exclusively through the mediation of a protection mutualism.

  8. Abiotic stress and the plant circadian clock

    PubMed Central

    Sanchez, Alfredo; Shin, Jieun

    2011-01-01

    In this review, we focus on the interaction between the circadian clock of higher plants to that of metabolic and physiological processes that coordinate growth and performance under a predictable, albeit changing environment. In this, the phytochrome and cryptochrome photoreceptors have shown to be important, but not essential for oscillator control under diurnal cycles of light and dark. From this foundation, we will examine how emerging findings have firmly linked the circadian clock, as a central mediator in the coordination of metabolism, to maintain homeostasis. This occurs by oscillator synchronization of global transcription, which leads to a dynamic control of a host of physiological processes. These include the determination of the levels of primary and secondary metabolites, and the anticipation of future environmental stresses, such as mid-day drought and midnight coldness. Interestingly, metabolic and stress cues themselves appear to feedback on oscillator function. In such a way, the circadian clock of plants and abiotic-stress tolerance appear to be firmly interconnected processes. PMID:21325898

  9. Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite

    SciTech Connect

    Veeramani, Harish; Scheinost, Andreas; Monsegue, Niven; Qafoku, Nikolla; Kukkadapu, Ravi K.; Newville, Mathew; Lanzirotti, Anthony; Pruden, Amy; Murayama, Mitsuhiro; Hochella, Michael F.

    2013-03-01

    During subsurface bioremediation of uranium-contaminated sites, indigenous metal and sulfate-reducing bacteria may utilize a variety of electron acceptors, including ferric iron and sulfate that could lead to the formation of various biogenic minerals in-situ. Sulfides, as well as structural and adsorbed Fe(II) associated with biogenic Fe(II)-sulfide phases, can potentially catalyze abiotic U6+ reduction via direct electron transfer processes. In the present work, the propensity of biogenic mackinawite (Fe1+xS, x = 0 to 0.11) to reduce U6+ abiotically was investigated. The biogenic mackinawite produced by Shewanella putrefaciens strain CN32 was characterized by employing a suite of analytical techniques including TEM, SEM, XAS and Mössbauer analyses. Nanoscale and bulk analyses (microscopic and spectroscopic techniques, respectively) of biogenic mackinawite after exposure to U6+ indicate the formation of nanoparticulate UO2. This study suggests the relevance of Fe(II) and sulfide bearing biogenic minerals in mediating abiotic U6+ reduction, an alternative pathway in addition to direct enzymatic U6+ reduction.

  10. Abiotic reductive immobilization of U(VI) by biogenic mackinawite.

    PubMed

    Veeramani, Harish; Scheinost, Andreas C; Monsegue, Niven; Qafoku, Nikolla P; Kukkadapu, Ravi; Newville, Matt; Lanzirotti, Antonio; Pruden, Amy; Murayama, Mitsuhiro; Hochella, Michael F

    2013-03-05

    During subsurface bioremediation of uranium-contaminated sites, indigenous metal and sulfate-reducing bacteria may utilize a variety of electron acceptors, including ferric iron and sulfate that could lead to the formation of various biogenic minerals in situ. Sulfides, as well as structural and adsorbed Fe(II) associated with biogenic Fe(II)-sulfide phases, can potentially catalyze abiotic U(VI) reduction via direct electron transfer processes. In the present work, the propensity of biogenic mackinawite (Fe 1+x S, x = 0 to 0.11) to reduce U(VI) abiotically was investigated. The biogenic mackinawite produced by Shewanella putrefaciens strain CN32 was characterized by employing a suite of analytical techniques including TEM, SEM, XAS, and Mössbauer analyses. Nanoscale and bulk analyses (microscopic and spectroscopic techniques, respectively) of biogenic mackinawite after exposure to U(VI) indicate the formation of nanoparticulate UO2. This study suggests the relevance of sulfide-bearing biogenic minerals in mediating abiotic U(VI) reduction, an alternative pathway in addition to direct enzymatic U(VI) reduction.

  11. Using thermodynamics to assess biotic and abiotic impediments to root water uptake

    NASA Astrophysics Data System (ADS)

    Bechmann, Marcel; Hildebrandt, Anke; Kleidon, Axel

    2016-04-01

    Root water uptake has been the subject of extensive research, dealing with understanding the processes limiting transpiration and understanding strategies of plants to avoid water stress. Many of those studies use models of water flow from the soil through the plant into the atmosphere to learn about biotic and abiotic factors affecting plant water relations. One important question in this context is to identify those processes that are most limiting to water transport, and specifically whether these processes lie within the plant or the soil? Here, we propose to use a thermodynamic formulation of root water uptake to answer this question. The method allows us to separate the energy exported at the root collar into a sum of energy fluxes related to all processes along the flow path, notably including the effect of increasing water retention in drier soils. Evaluation of the several contributions allows us to identify and rank the processes by how much these impede water flow from the soil to the atmosphere. The application of this approach to a complex 3-dimensional root water uptake model reveals insights on the role of root versus soil resistances to limit water flow. We investigate the efficiency of root water uptake in an ensemble of root systems with varying root hydraulic properties. While root morphology is kept the same, root radial and axial resistances are artificially varied. Starting with entirely young systems (uptake roots, high radial, low axial conductance) we increasingly add older roots (transport roots, high axial, low radial conductance) to improve transport within root systems. This yields a range of root hydraulic architectures, where the extremes are limited either by radial uptake capacity or low capacity to transport water along the root system. We model root water uptake in this range of root systems with a 3-dimensional root water uptake model in two different soils, applying constant flux boundary conditions in a dry down experiment and

  12. Parental concern about vaccine safety in Canadian children partially immunized at age 2: a multivariable model including system level factors.

    PubMed

    MacDonald, Shannon E; Schopflocher, Donald P; Vaudry, Wendy

    2014-01-01

    Children who begin but do not fully complete the recommended series of childhood vaccines by 2 y of age are a much larger group than those who receive no vaccines. While parents who refuse all vaccines typically express concern about vaccine safety, it is critical to determine what influences parents of 'partially' immunized children. This case-control study examined whether parental concern about vaccine safety was responsible for partial immunization, and whether other personal or system-level factors played an important role. A random sample of parents of partially and completely immunized 2 y old children were selected from a Canadian regional immunization registry and completed a postal survey assessing various personal and system-level factors. Unadjusted odds ratios (OR) and adjusted ORs (aOR) were calculated with logistic regression. While vaccine safety concern was associated with partial immunization (OR 7.338, 95% CI 4.138-13.012), other variables were more strongly associated and reduced the strength of the relationship between concern and partial immunization in multivariable analysis (aOR 2.829, 95% CI 1.151-6.957). Other important factors included perceived disease susceptibility and severity (aOR 4.629, 95% CI 2.017-10.625), residential mobility (aOR 3.908, 95% CI 2.075-7.358), daycare use (aOR 0.310, 95% CI 0.144-0.671), number of needles administered at each visit (aOR 7.734, 95% CI 2.598-23.025) and access to a regular physician (aOR 0.219, 95% CI 0.057-0.846). While concern about vaccine safety may be addressed through educational strategies, this study suggests that additional program and policy-level strategies may positively impact immunization uptake.

  13. Selection of Reliable Reference Genes for Gene Expression Analysis under Abiotic Stresses in the Desert Biomass Willow, Salix psammophila.

    PubMed

    Li, Jianbo; Jia, Huixia; Han, Xiaojiao; Zhang, Jin; Sun, Pei; Lu, Mengzhu; Hu, Jianjun

    2016-01-01

    Salix psammophila is a desert shrub willow that has extraordinary adaptation to abiotic stresses and plays an important role in maintaining local ecosystems. Moreover, S. psammophila is regarded as a promising biomass feedstock because of its high biomass yields and short rotation coppice cycle. However, few suitable reference genes (RGs) for quantitative real-time polymerase chain reaction (qRT-PCR) constrain the study on normalization of gene expression in S. psammophila until now. Here, we investigated the expression stabilities of 14 candidate RGs across tissue types and under four abiotic stress treatments, including heat, cold, salt, and drought treatments. After calculation of PCR efficiencies, three different software, NormFinder, geNorm, and BestKeeper were employed to analyze systematically the qRT-PCR data, and the outputs were merged by RankAggreg software. The optimal RGs selected for gene expression analysis were EF1α (Elongation factor-1 alpha) and OTU (OTU-like cysteine protease family protein) for different tissue types, UBC (Ubiquitin-conjugating enzyme E2) and LTA4H (Leukotriene A-4 hydrolase homolog) for heat treatment, HIS (Histone superfamily protein H3) and ARF2 (ADP-ribosylation factor 2) for cold treatment, OTU and ACT7 (Actin 7) for salt treatment, UBC and LTA4H for drought treatment. The expression of UBC, ARF2, and VHAC (V-type proton ATPase subunit C) varied the least across tissue types and under abiotic stresses. Furthermore, the relative genes expression profiles of one tissue-specific gene WOX1a (WUSCHEL-related homeobox 1a), and four stress-inducible genes, including Hsf-A2 (Heat shock transcription factors A2), CBF3 (C-repeat binding factor 3), HKT1 (High-Affinity K(+) Transporter 1), and GST (Glutathione S-transferase), were conducted to confirm the validity of the RGs in this study. These results provided an important RGs application guideline for gene expression characterization in S. psammophila.

  14. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions.

    PubMed

    Coari, Kristin M; Martin, Rebecca C; Jain, Kopal; McGown, Linda B

    2017-02-03

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  15. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions

    NASA Astrophysics Data System (ADS)

    Coari, Kristin M.; Martin, Rebecca C.; Jain, Kopal; McGown, Linda B.

    2017-02-01

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  16. Prognostic factors of successful on-purpose tumor biopsies in metastatic cancer patients included in the SHIVA prospective clinical trial

    PubMed Central

    Desportes, Emilie; Wagner, Mathilde; Kamal, Maud; Salomon, Anne Vincent; Deniziaut, Gabrielle; Pierron, Gaëlle; Rouleau, Etienne; Jouffroy, Thomas; Le Tourneau, Christophe; Paoletti, Xavier; Servois, Vincent

    2017-01-01

    PURPOSE To identify patient/tumor characteristics associated with success of biopsy in patients who received multiple lines of chemotherapy. METHODS Patients with refractory cancer from our center, who were included in a prospective randomized phase II trial comparing targeted therapies based on molecular profile of tumors versus conventional chemotherapy, were retrospectively included in this IRB-approved study. All patients had a biopsy of a tumor lesion performed during surgery, or using CT/palpation/endoscopic guidance. A biopsy was considered successful if the neoplastic cellularity was greater than 30%. Primary lesion, size and location of biopsied lesion, on-going chemotherapy and the differential attenuation between non-enhanced and venous phase (HU) for CT-guided biopsied lesions were recorded. RESULTS 228 patients (age=59±15yo; M/F=1.9) were included. One hundred and sixty biopsies (72%) of the 221 biopsies performed were successful. Prognostic factors of biopsy success were: no ongoing chemotherapy, surgical or palpation-guided biopsy, lymph nodes/soft tissue location(P <0.01). Among the 221 performed biopsies, 122 (55%) were performed using CT guidance and 82 (67%) were successful. In this subgroup, biopsied lesions located in lymph nodes/soft tissue were associated with a higher success rate while lung location was associated with failure (P <0.01). The mean differential attenuation was significantly higher in lesions with a successful biopsy (P <0.001). CONCLUSION Success of biopsy was less frequent with CT guidance than with surgical or palpation-guided biopsy and was higher in soft tissues and lymph nodes than that in visceral metastasis. Ongoing chemotherapy decreased tumor cell content and consequently the success of the biopsy samples for molecular profiling. PMID:27655703

  17. Cell Wall Metabolism in Response to Abiotic Stress.

    PubMed

    Le Gall, Hyacinthe; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

    2015-02-16

    This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

  18. Cell Wall Metabolism in Response to Abiotic Stress

    PubMed Central

    Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

    2015-01-01

    This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

  19. Molecular responses of genetically modified maize to abiotic stresses as determined through proteomic and metabolomic analyses.

    PubMed

    Benevenuto, Rafael Fonseca; Agapito-Tenfen, Sarah Zanon; Vilperte, Vinicius; Wikmark, Odd-Gunnar; van Rensburg, Peet Jansen; Nodari, Rubens Onofre

    2017-01-01

    Some genetically modified (GM) plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA) analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses.

  20. Molecular responses of genetically modified maize to abiotic stresses as determined through proteomic and metabolomic analyses

    PubMed Central

    Benevenuto, Rafael Fonseca; Agapito-Tenfen, Sarah Zanon; Vilperte, Vinicius; Wikmark, Odd-Gunnar; van Rensburg, Peet Jansen; Nodari, Rubens Onofre

    2017-01-01

    Some genetically modified (GM) plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA) analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses. PMID:28245233

  1. A review of selection-based tests of abiotic surrogates for species representation.

    PubMed

    Beier, Paul; Sutcliffe, Patricia; Hjort, Jan; Faith, Daniel P; Pressey, Robert L; Albuquerque, Fabio

    2015-06-01

    Because conservation planners typically lack data on where species occur, environmental surrogates--including geophysical settings and climate types--have been used to prioritize sites within a planning area. We reviewed 622 evaluations of the effectiveness of abiotic surrogates in representing species in 19 study areas. Sites selected using abiotic surrogates represented more species than an equal number of randomly selected sites in 43% of tests (55% for plants) and on average improved on random selection of sites by about 8% (21% for plants). Environmental diversity (ED) (42% median improvement on random selection) and biotically informed clusters showed promising results and merit additional testing. We suggest 4 ways to improve performance of abiotic surrogates. First, analysts should consider a broad spectrum of candidate variables to define surrogates, including rarely used variables related to geographic separation, distance from coast, hydrology, and within-site abiotic diversity. Second, abiotic surrogates should be defined at fine thematic resolution. Third, sites (the landscape units prioritized within a planning area) should be small enough to ensure that surrogates reflect species' environments and to produce prioritizations that match the spatial resolution of conservation decisions. Fourth, if species inventories are available for some planning units, planners should define surrogates based on the abiotic variables that most influence species turnover in the planning area. Although species inventories increase the cost of using abiotic surrogates, a modest number of inventories could provide the data needed to select variables and evaluate surrogates. Additional tests of nonclimate abiotic surrogates are needed to evaluate the utility of conserving nature's stage as a strategy for conservation planning in the face of climate change.

  2. Effect of yoga practices on pulmonary function tests including transfer factor of lung for carbon monoxide (TLCO) in asthma patients.

    PubMed

    Singh, Savita; Soni, Ritu; Singh, K P; Tandon, O P

    2012-01-01

    Prana is the energy, when the self-energizing force embraces the body with extension and expansion and control, it is pranayama. It may affect the milieu at the bronchioles and the alveoli particularly at the alveolo-capillary membrane to facilitate diffusion and transport of gases. It may also increase oxygenation at tissue level. Aim of our study is to compare pulmonary functions and diffusion capacity in patients of bronchial asthma before and after yogic intervention of 2 months. Sixty stable asthmatic-patients were randomized into two groups i.e group 1 (Yoga training group) and group 2 (control group). Each group included thirty patients. Lung functions were recorded on all patients at baseline, and then after two months. Group 1 subjects showed a statistically significant improvement (P<0.001) in Transfer factor of the lung for carbon monoxide (TLCO), forced vital capacity (FVC), forced expiratory volume in 1st sec (FEV1), peak expiratory flow rate (PEFR), maximum voluntary ventilation (MVV) and slow vital capacity (SVC) after yoga practice. Quality of life also increased significantly. It was concluded that pranayama & yoga breathing and stretching postures are used to increase respiratory stamina, relax the chest muscles, expand the lungs, raise energy levels, and calm the body.

  3. Research advances in major cereal crops for adaptation to abiotic stresses

    PubMed Central

    Maiti, RK; Satya, Pratik

    2014-01-01

    With devastating increase in population there is a great necessity to increase crop productivity of staple crops but the productivity is greatly affected by various abiotic stress factors such as drought, salinity. An attempt has been made a brief account on abiotic stress resistance of major cereal crops viz. In spite of good successes obtained on physiological and use molecular biology, the benefits of this high cost technology are beyond the reach of developing countries. This review discusses several morphological, anatomical, physiological, biochemical and molecular mechanisms of major cereal crops related to the adaptation of these crop to abiotic stress factors. It discusses the effect of abiotic stresses on physiological processes such as flowering, grain filling and maturation and plant metabolisms viz. photosynthesis, enzyme activity, mineral nutrition, and respiration. Though significant progress has been attained on the physiological, biochemical basis of resistance to abiotic stress factors, very little progress has been achieved to increase productivity under sustainable agriculture. Therefore, there is a great necessity of inter-disciplinary research to address this issue and to evolve efficient technology and its transfer to the farmers’ fields. PMID:25523172

  4. The Functions of the A1A2A3 Domains in Von Willebrand Factor Include Multimerin 1 Binding

    PubMed Central

    Parker, D’Andra N.; Tasneem, Subia; Farndale, Richard W.; Bihan, Dominique; Sadler, J. Evan; Sebastian, Silvie; De Groot, Philip G.

    2016-01-01

    Summary Multimerin 1 (MMRN1) is a massive, homopolymeric protein that is stored in platelets and endothelial cells for activation-induced release. In vitro, MMRN1 binds to the outer surfaces of activated platelets and endothelial cells, the extracellular matrix (including collagen) and von Willebrand factor (VWF) to support platelet adhesive functions. VWF associates with MMRN1 at high shear, not static conditions, suggesting that shear exposes cryptic sites within VWF that support MMRN1 binding. Modified ELISA and surface plasmon resonance were used to study the structural features of VWF that support MMRN1 binding, and determine the affinities for VWF-MMRN1 binding. High shear microfluidic platelet adhesion assays determined the functional consequences for VWF-MMRN1 binding. VWF binding to MMRN1 was enhanced by shear exposure and ristocetin, and required VWF A1A2A3 region, specifically the A1 and A3 domains. VWF A1A2A3 bound to MMRN1 with a physiologically relevant binding affinity (KD: 2.0 ± 0.4 nM), whereas the individual VWF A1 (KD: 39.3 ± 7.7 nM) and A3 domains (KD: 229 ± 114 nM) bound to MMRN1 with lower affinities. VWF A1A2A3 was also sufficient to support the adhesion of resting platelets to MMRN1 at high shear, by a mechanism dependent on VWF-GPIbα binding. Our study provides new information on the molecular basis of MMRN1 binding to VWF, and its role in supporting platelet adhesion at high shear. We propose that at sites of vessel injury, MMRN1 that is released following activation of platelets and endothelial cells, binds to VWF A1A2A3 region to support platelet adhesion at arterial shear rates. PMID:27052467

  5. Hydrogeomorphic Classification of Wetlands on Mt. Desert Island, Maine, Including Hydrologic Susceptibility Factors for Wetlands in Acadia National Park

    USGS Publications Warehouse

    Nielsen, Martha G.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service, developed a hydrogeomorphic (HGM) classification system for wetlands greater than 0.4 hectares (ha) on Mt. Desert Island, Maine, and applied this classification using map-scale data to more than 1,200 mapped wetland units on the island. In addition, two hydrologic susceptibility factors were defined for a subset of these wetlands, using 11 variables derived from landscape-scale characteristics of the catchment areas of these wetlands. The hydrologic susceptibility factors, one related to the potential hydrologic pathways for contaminants and the other to the susceptibility of wetlands to disruptions in water supply from projected future changes in climate, were used to indicate which wetlands (greater than 1 ha) in Acadia National Park (ANP) may warrant further investigation or monitoring. The HGM classification system consists of 13 categories: Riverine-Upper Perennial, Riverine-Nonperennial, Riverine- Tidal, Depressional-Closed, Depressional-Semiclosed, Depressional-Open, Depressional-No Ground-Water Input, Mineral Soil Flat, Organic Soil Flat, Tidal Fringe, Lacustrine Fringe, Slope, and Hilltop/Upper Hillslope. A dichotomous key was developed to aid in the classification of wetlands. The National Wetland Inventory maps produced by the U.S. Fish and Wildlife Service provided the wetland mapping units used for this classification. On the basis of topographic map information and geographic information system (GIS) layers at a scale of 1:24,000 or larger, 1,202 wetland units were assigned a preliminary HGM classification. Two of the 13 HGM classes (Riverine-Tidal and Depressional-No Ground-Water Input) were not assigned to any wetlands because criteria for determining those classes are not available at that map scale, and must be determined by more site-specific information. Of the 1,202 wetland polygons classified, which cover 1,830 ha in ANP, 327 were classified as Slope, 258 were

  6. Abiotic Versus Biotic Weathering Of Olivine As Possible Biosignatures

    NASA Technical Reports Server (NTRS)

    Longazo, Teresa G.; Wentworth, Susan J.; Clemett, Simon J.; Southam, Gordon; McKay, David S.

    2001-01-01

    We are investigating the weathering of silicate minerals by both purely inorganic, and biologically mediated processes using field-emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDS). By resolving surface textures and chemical compositions of weathered surfaces at the sub-micron scale we hope to be able to distinguish abiotic from biotic weathering processes and so establish a new biosignature applicable to the study of astromaterials including but not limited to the Martian meteorites. Sterilized olivine grains (San Carlos, Arizona) no more than 1-2 mm in their longest dimension were optically assayed to be uniform in color and free of inclusions were selected as weathering subjects. Prior to all experiments surface morphologies and Fe/Mg ratios were determined for each grain using FE-SEM and EDS. Experiments were divided into two categories abiotic and biotic and were compared with "naturally" weathered samples. For the preliminary experiments, two trials (open and closed to the ambient laboratory environment) were performed under abiotic conditions, and three trials under biotic conditions (control, day 1 and day 2). The open system abiotic trials used sterile grains heated at 98 C and 200 C for both 24 and 48 hours in 1L double distilled de-ionized water. The closed system abiotic trials were conducted under the same conditions but in a sealed two layer steel/Teflon "bomb" apparatus. The biotic trials used sterile grains mounted in a flow-through device attached to a wellhead on the Columbia River aquifer. Several discolored, altered, grains were selected to document "natural" weathering surface textures for comparison with the experimental samples. Preliminary results indicate there are qualitative differences in weathered surface textures among all the designed experiments. The olivine grains in abiotic trials displayed etching, pitting, denticulate margins, dissolution and clay formation. The scale of the features

  7. Abiotic-biotic characterization of Pt/Ir microelectrode arrays in chronic implants

    PubMed Central

    Prasad, Abhishek; Xue, Qing-Shan; Dieme, Robert; Sankar, Viswanath; Mayrand, Roxanne C.; Nishida, Toshikazu; Streit, Wolfgang J.; Sanchez, Justin C.

    2014-01-01

    Pt/Ir electrodes have been extensively used in neurophysiology research in recent years as they provide a more inert recording surface as compared to tungsten or stainless steel. While floating microelectrode arrays (FMA) consisting of Pt/Ir electrodes are an option for neuroprosthetic applications, long-term in vivo functional performance characterization of these FMAs is lacking. In this study, we have performed comprehensive abiotic-biotic characterization of Pt/Ir arrays in 12 rats with implant periods ranging from 1 week up to 6 months. Each of the FMAs consisted of 16-channel, 1.5 mm long, and 75 μm diameter microwires with tapered tips that were implanted into the somatosensory cortex. Abiotic characterization included (1) pre-implant and post-explant scanning electron microscopy (SEM) to study recording site changes, insulation delamination and cracking, and (2) chronic in vivo electrode impedance spectroscopy. Biotic characterization included study of microglial responses using a panel of antibodies, such as Iba1, ED1, and anti-ferritin, the latter being indicative of blood-brain barrier (BBB) disruption. Significant structural variation was observed pre-implantation among the arrays in the form of irregular insulation, cracks in insulation/recording surface, and insulation delamination. We observed delamination and cracking of insulation in almost all electrodes post-implantation. These changes altered the electrochemical surface area of the electrodes and resulted in declining impedance over the long-term due to formation of electrical leakage pathways. In general, the decline in impedance corresponded with poor electrode functional performance, which was quantified via electrode yield. Our abiotic results suggest that manufacturing variability and insulation material as an important factor contributing to electrode failure. Biotic results show that electrode performance was not correlated with microglial activation (neuroinflammation) as we were able

  8. Receptor modelling of fine particles in southern England using CMB including comparison with AMS-PMF factors

    NASA Astrophysics Data System (ADS)

    Yin, J.; Cumberland, S. A.; Harrison, R. M.; Allan, J.; Young, D. E.; Williams, P. I.; Coe, H.

    2015-02-01

    PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January-February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulfate and sea salt. Good mass closure was achieved with 81% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15 and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4 and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is rather

  9. Receptor modelling of fine particles in Southern England using CMB including comparison with AMS-PMF factors

    NASA Astrophysics Data System (ADS)

    Yin, J.; Cumberland, S. A.; Harrison, R. M.; Allan, J.; Young, D. E.; Williams, P. I.; Coe, H.

    2014-09-01

    PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January-February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulphate and sea salt. Good mass closure was achieved with 8% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15% and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4% and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is

  10. The Role and Regulation of ABI5 (ABA-Insensitive 5) in Plant Development, Abiotic Stress Responses and Phytohormone Crosstalk

    PubMed Central

    Skubacz, Anna; Daszkowska-Golec, Agata; Szarejko, Iwona

    2016-01-01

    ABA Insensitive 5 (ABI5) is a basic leucine zipper transcription factor that plays a key role in the regulation of seed germination and early seedling growth in the presence of ABA and abiotic stresses. ABI5 functions in the core ABA signaling, which is composed of PYR/PYL/RCAR receptors, PP2C phosphatases and SnRK2 kinases, through the regulation of the expression of genes that contain the ABSCISIC ACID RESPONSE ELEMENT (ABRE) motif within their promoter region. The regulated targets include stress adaptation genes, e.g., LEA proteins. However, the expression and activation of ABI5 is not only dependent on the core ABA signaling. Many transcription factors such as ABI3, ABI4, MYB7 and WRKYs play either a positive or a negative role in the regulation of ABI5 expression. Additionally, the stability and activity of ABI5 are also regulated by other proteins through post-translational modifications such as phosphorylation, ubiquitination, sumoylation and S-nitrosylation. Moreover, ABI5 also acts as an ABA and other phytohormone signaling integrator. Components of auxin, cytokinin, gibberellic acid, jasmonate and brassinosteroid signaling and metabolism pathways were shown to take part in ABI5 regulation and/or to be regulated by ABI5. Monocot orthologs of AtABI5 have been identified. Although their roles in the molecular and physiological adaptations during abiotic stress have been elucidated, knowledge about their detailed action still remains elusive. Here, we describe the recent advances in understanding the action of ABI5 in early developmental processes and the adaptation of plants to unfavorable environmental conditions. We also focus on ABI5 relation to other phytohormones in the abiotic stress response of plants. PMID:28018412

  11. Catchment process affecting drinking water quality, including the significance of rainfall events, using factor analysis and event mean concentrations.

    PubMed

    Cinque, Kathy; Jayasuriya, Niranjali

    2010-12-01

    To ensure the protection of drinking water an understanding of the catchment processes which can affect water quality is important as it enables targeted catchment management actions to be implemented. In this study factor analysis (FA) and comparing event mean concentrations (EMCs) with baseline values were techniques used to asses the relationships between water quality parameters and linking those parameters to processes within an agricultural drinking water catchment. FA found that 55% of the variance in the water quality data could be explained by the first factor, which was dominated by parameters usually associated with erosion. Inclusion of pathogenic indicators in an additional FA showed that Enterococcus and Clostridium perfringens (C. perfringens) were also related to the erosion factor. Analysis of the EMCs found that most parameters were significantly higher during periods of rainfall runoff. This study shows that the most dominant processes in an agricultural catchment are surface runoff and erosion. It also shows that it is these processes which mobilise pathogenic indicators and are therefore most likely to influence the transport of pathogens. Catchment management efforts need to focus on reducing the effect of these processes on water quality.

  12. Ethylene Response Factors: A Key Regulatory Hub in Hormone and Stress Signaling.

    PubMed

    Müller, Maren; Munné-Bosch, Sergi

    2015-09-01

    Ethylene is essential for many developmental processes and a key mediator of biotic and abiotic stress responses in plants. The ethylene signaling and response pathway includes Ethylene Response Factors (ERFs), which belong to the transcription factor family APETALA2/ERF. It is well known that ERFs regulate molecular response to pathogen attack by binding to sequences containing AGCCGCC motifs (the GCC box), a cis-acting element. However, recent studies suggest that several ERFs also bind to dehydration-responsive elements and act as a key regulatory hub in plant responses to abiotic stresses. Here, we review some of the recent advances in our understanding of the ethylene signaling and response pathway, with emphasis on ERFs and their role in hormone cross talk and redox signaling under abiotic stresses. We conclude that ERFs act as a key regulatory hub, integrating ethylene, abscisic acid, jasmonate, and redox signaling in the plant response to a number of abiotic stresses.

  13. Ethylene Response Factors: A Key Regulatory Hub in Hormone and Stress Signaling1

    PubMed Central

    Müller, Maren; Munné-Bosch, Sergi

    2015-01-01

    Ethylene is essential for many developmental processes and a key mediator of biotic and abiotic stress responses in plants. The ethylene signaling and response pathway includes Ethylene Response Factors (ERFs), which belong to the transcription factor family APETALA2/ERF. It is well known that ERFs regulate molecular response to pathogen attack by binding to sequences containing AGCCGCC motifs (the GCC box), a cis-acting element. However, recent studies suggest that several ERFs also bind to dehydration-responsive elements and act as a key regulatory hub in plant responses to abiotic stresses. Here, we review some of the recent advances in our understanding of the ethylene signaling and response pathway, with emphasis on ERFs and their role in hormone cross talk and redox signaling under abiotic stresses. We conclude that ERFs act as a key regulatory hub, integrating ethylene, abscisic acid, jasmonate, and redox signaling in the plant response to a number of abiotic stresses. PMID:26103991

  14. A NAP-Family Histone Chaperone Functions in Abiotic Stress Response and Adaptation1[OPEN

    PubMed Central

    Pareek, Ashwani; Singla-Pareek, Sneh Lata

    2016-01-01

    Modulation of gene expression is one of the most significant molecular mechanisms of abiotic stress response in plants. Via altering DNA accessibility, histone chaperones affect the transcriptional competence of genomic loci. However, in contrast to other factors affecting chromatin dynamics, the role of plant histone chaperones in abiotic stress response and adaptation remains elusive. Here, we studied the physiological function of a stress-responsive putative rice (Oryza sativa) histone chaperone of the NAP superfamily: OsNAPL6. We show that OsNAPL6 is a nuclear-localized H3/H4 histone chaperone capable of assembling a nucleosome-like structure. Utilizing overexpression and knockdown approaches, we found a positive correlation between OsNAPL6 expression levels and adaptation to multiple abiotic stresses. Results of comparative transcriptome profiling and promoter-recruitment studies indicate that OsNAPL6 functions during stress response via modulation of expression of various genes involved in diverse functions. For instance, we show that OsNAPL6 is recruited to OsRad51 promoter, activating its expression and leading to more efficient DNA repair and abrogation of programmed cell death under salinity and genotoxic stress conditions. These results suggest that the histone chaperone OsNAPL6 may serve a regulatory role in abiotic stress physiology possibly via modulating nucleosome dynamics at various stress-associated genomic loci. Taken together, our findings establish a hitherto unknown link between histone chaperones and abiotic stress response in plants. PMID:27342307

  15. Assessing Utilization and Environmental Risks of Important Genes in Plant Abiotic Stress Tolerance

    PubMed Central

    Khan, Mohammad S.; Khan, Muhammad A.; Ahmad, Dawood

    2016-01-01

    Transgenic plants with improved salt and drought stress tolerance have been developed with a large number of abiotic stress-related genes. Among these, the most extensively used genes are the glycine betaine biosynthetic codA, the DREB transcription factors, and vacuolar membrane Na+/H+ antiporters. The use of codA, DREBs, and Na+/H+ antiporters in transgenic plants has conferred stress tolerance and improved plant phenotype. However, the future deployment and commercialization of these plants depend on their safety to the environment. Addressing environmental risk assessment is challenging since mechanisms governing abiotic stress tolerance are much more complex than that of insect resistance and herbicide tolerance traits, which have been considered to date. Therefore, questions arise, whether abiotic stress tolerance genes need additional considerations and new measurements in risk assessment and, whether these genes would have effects on weediness and invasiveness potential of transgenic plants? While considering these concerns, the environmental risk assessment of abiotic stress tolerance genes would need to focus on the magnitude of stress tolerance, plant phenotype and characteristics of the potential receiving environment. In the present review, we discuss environmental concerns and likelihood of concerns associated with the use of abiotic stress tolerance genes. Based on our analysis, we conclude that the uses of these genes in domesticated crop plants are safe for the environment. Risk assessment, however, should be carefully conducted on biofeedstocks and perennial plants taking into account plant phenotype and the potential receiving environment. PMID:27446095

  16. Distinguishing Biotic from Abiotic Phosphate Oxygen Isotopic Signatures

    NASA Astrophysics Data System (ADS)

    Blake, R.; Moyer, C.; Colman, A.; Liang, Y.; Dogru, D.

    2006-05-01

    On earth, phosphate has a strong biological oxygen isotope signature due to its concentration and intense cycling by living organisms as an essential nutrient. Phosphate does not undergo oxygen isotope exchange with water at low temperature without enzymatic catalysis, making the oxygen isotope ratio (18O/16O) of phosphate, δ18OP, an attractive biosignature in the search for early and extraterrestrial life. Recent laboratory and field studies have demonstrated that the δ18OP value of dissolved inorganic phosphate (PO4) records specific microbial activity and enzymatic reaction pathways in both laboratory cultures and natural waters/sediments (Blake et al., 2005; Colman et al 2005; Liang and Blake, 2005). Phosphate oxygen isotope biosignatures may be distinguished from abiotic signatures by: (1) evaluating the degree of temperature-dependent PO4-water oxygen isotope exchange in aqueous systems and deviation from equilibrium; and (2) evolution from an abiotic P reservoir signature towards a biotic P reservoir signature. Important abiotic processes potentially affecting phosphate δ18OP values include dissolution/precipitation, adsorption/desorption, recrystallization of PO4 mineral phases, diagenesis and metamorphism. For most of these processes, the recording, retention and alteration of δ18OP biosignatures have not been evaluated. Deep-sea hydrothermal vent fields are an ideal system in which to study the preservation and alteration of δ18OP biosignatures, as well as potential look-alikes produced by heat-promoted PO4 -water oxygen isotope exchange. Results from recent studies of δ18OP biosignatures in hydrothermal deposits near 9 and 21 degrees N. EPR and at Loihi seamount will be presented.

  17. Generating induced pluripotent stem cells from common marmoset (Callithrix jacchus) fetal liver cells using defined factors, including Lin28.

    PubMed

    Tomioka, Ikuo; Maeda, Takuji; Shimada, Hiroko; Kawai, Kenji; Okada, Yohei; Igarashi, Hiroshi; Oiwa, Ryo; Iwasaki, Tsuyoshi; Aoki, Mikio; Kimura, Toru; Shiozawa, Seiji; Shinohara, Haruka; Suemizu, Hiroshi; Sasaki, Erika; Okano, Hideyuki

    2010-09-01

    Although embryonic stem (ES) cell-like induced pluripotent stem (iPS) cells have potential therapeutic applications in humans, they are also useful for creating genetically modified human disease models in nonhuman primates. In this study, we generated common marmoset iPS cells from fetal liver cells via the retrovirus-mediated introduction of six human transcription factors: Oct-3/4, Sox2, Klf4, c-Myc, Nanog, and Lin28. Four to five weeks after introduction, several colonies resembling marmoset ES cells were observed and picked for further expansion in ES cell medium. Eight cell lines were established, and validation analyses of the marmoset iPS cells followed. We detected the expression of ES cell-specific surface markers. Reverse transcription-PCR showed that these iPS cells expressed endogenous Oct-3/4, Sox2, Klf4, c-Myc, Nanog and Lin28 genes, whereas all of the transgenes were silenced. Karyotype analysis showed that two of three iPS cell lines retained a normal karyotype after a 2-month culture. Both embryoid body and teratoma formation showed that marmoset iPS cells had the developmental potential to give rise to differentiated derivatives of all three primary germ layers. In summary, we generated marmoset iPS cells via the transduction of six transcription factors; this provides a powerful preclinical model for studies in regenerative medicine.

  18. How plants handle multiple stresses: hormonal interactions underlying responses to abiotic stress and insect herbivory.

    PubMed

    Nguyen, Duy; Rieu, Ivo; Mariani, Celestina; van Dam, Nicole M

    2016-08-01

    Adaptive plant responses to specific abiotic stresses or biotic agents are fine-tuned by a network of hormonal signaling cascades, including abscisic acid (ABA), ethylene, jasmonic acid (JA) and salicylic acid. Moreover, hormonal cross-talk modulates plant responses to abiotic stresses and defenses against insect herbivores when they occur simultaneously. How such interactions affect plant responses under multiple stresses, however, is less understood, even though this may frequently occur in natural environments. Here, we review our current knowledge on how hormonal signaling regulates abiotic stress responses and defenses against insects, and discuss the few recent studies that attempted to dissect hormonal interactions occurring under simultaneous abiotic stress and herbivory. Based on this we hypothesize that drought stress enhances insect resistance due to synergistic interactions between JA and ABA signaling. Responses to flooding or waterlogging involve ethylene signaling, which likely reduces plant resistance to chewing herbivores due to its negative cross-talk with JA. However, the outcome of interactions between biotic and abiotic stress signaling is often plant and/or insect species-dependent and cannot simply be predicted based on general knowledge on the involvement of signaling pathways in single stress responses. More experimental data on non-model plant and insect species are needed to reveal general patterns and better understand the molecular mechanisms allowing plants to optimize their responses in complex environments.

  19. Factors associated with a clinician's offer of screening HIV-positive patients for sexually transmitted infections, including syphilis.

    PubMed

    Heller, R; Fernando, I; MacDougall, M

    2011-06-01

    This retrospective study assessed whether Quality Improvement Scotland national standards for the sexual health care offered to HIV-positive individuals are being met by the Edinburgh genitourinary (GU) medicine clinic; specifically whether HIV-positive patients are offered: (a) sexually transmitted infection (STI) screening annually and (b) syphilis testing six-monthly. The study also reviewed what factors were associated with a clinician's offer of STI screening and syphilis testing. Of the 509 patients seen within the study period, case notes documented that 64% were offered STI screens, and 69% were offered syphilis testing, results consistent with audits of services elsewhere. Sexual orientation (P < 0.0005), relationship status (P = 0.007) and receipt of antiretrovirals (P = 0.001) were independent predictors of clinician offer of STI screening, while gender (P < 0.0005) and receipt of antiretrovirals (P = 0.063) were independent predictors of offer of syphilis testing. Our results suggest that one explanation for clinicians failing to offer STI screens and syphilis serology testing is their (implicit) risk assessment that STI testing is not required in individual patients.

  20. Correlations Between the Incidence of National Notifiable Infectious Diseases and Public Open Data, Including Meteorological Factors and Medical Facility Resources

    PubMed Central

    Jang, Jin-Hwa; Lee, Ji-Hae; Je, Mi-Kyung; Cho, Myeong-Ji; Bae, Young Mee; Son, Hyeon Seok; Ahn, Insung

    2015-01-01

    Objectives: This study was performed to investigate the relationship between the incidence of national notifiable infectious diseases (NNIDs) and meteorological factors, air pollution levels, and hospital resources in Korea. Methods: We collected and stored 660 000 pieces of publicly available data associated with infectious diseases from public data portals and the Diseases Web Statistics System of Korea. We analyzed correlations between the monthly incidence of these diseases and monthly average temperatures and monthly average relative humidity, as well as vaccination rates, number of hospitals, and number of hospital beds by district in Seoul. Results: Of the 34 NNIDs, malaria showed the most significant correlation with temperature (r=0.949, p<0.01) and concentration of nitrogen dioxide (r=-0.884, p<0.01). We also found a strong correlation between the incidence of NNIDs and the number of hospital beds in 25 districts in Seoul (r=0.606, p<0.01). In particular, Geumcheon-gu was found to have the lowest incidence rate of NNIDs and the highest number of hospital beds per patient. Conclusions: In this study, we conducted a correlational analysis of public data from Korean government portals that can be used as parameters to forecast the spread of outbreaks. PMID:26265666

  1. Reserve, thin form-factor, hypochlorite-based cells for powering portable systems: Manufacture (including MEMS processes), performance and characterization

    NASA Astrophysics Data System (ADS)

    Cardenas-Valencia, Andres M.; Biver, Carl J.; Langebrake, Larry

    This work focuses on fabrication routes and performance evaluation of thin form-factors, reserve cells, as a powering alternative for expendable and/or remotely operated systems. The catalytic decomposition of sodium hypochlorite solutions is revisited herein with two cost-effective anodes: zinc and aluminum. Aluminum, even though the most expensive of the utilized anodes, constituted cells with double the energy content (up to 55 Wh kg -1) than those fabricated with zinc. Even though the hypochlorite concentration in the solution limits the cells' operational life, attractive performances (1.0 V with a current of 10 mA) for the manufactured cells are obtained. It is shown that micro fabrication processes, allowing for close electrodes interspacing, provided high faradic and columbic efficiencies of up to 70 and 100%, respectively. Obtained specific energies (50-120 Wh kg -1) are in the same order of magnitude than batteries currently used for powering deployable systems. Experimental results show that a simple model that linearly relates over potentials and the electrical load, adequately describe all the cell designs. A mathematical model based on a kinetic-mechanistic scheme that relates the current output as a function of time agrees fairly well with results obtained activating cells with various concentrations of NaOCl solutions.

  2. RNA helicases: diverse roles in prokaryotic response to abiotic stress.

    PubMed

    Owttrim, George W

    2013-01-01

    Similar to proteins, RNA molecules must fold into the correct conformation and associate with protein complexes in order to be functional within a cell. RNA helicases rearrange RNA secondary structure and RNA-protein interactions in an ATP-dependent reaction, performing crucial functions in all aspects of RNA metabolism. In prokaryotes, RNA helicase activity is associated with roles in housekeeping functions including RNA turnover, ribosome biogenesis, translation and small RNA metabolism. In addition, RNA helicase expression and/or activity are frequently altered during cellular response to abiotic stress, implying they perform defined roles during cellular adaptation to changes in the growth environment. Specifically, RNA helicases contribute to the formation of cold-adapted ribosomes and RNA degradosomes, implying a role in alleviation of RNA secondary structure stabilization at low temperature. A common emerging theme involves RNA helicases acting as scaffolds for protein-protein interaction and functioning as molecular clamps, holding RNA-protein complexes in specific conformations. This review highlights recent advances in DEAD-box RNA helicase association with cellular response to abiotic stress in prokaryotes.

  3. Ubiquitination pathway as a target to develop abiotic stress tolerance in rice

    PubMed Central

    Dametto, Andressa; Buffon, Giseli; Dos Reis Blasi, Édina Aparecida; Sperotto, Raul Antonio

    2015-01-01

    Abiotic stresses may result in significant losses in rice grain productivity. Protein regulation by the ubiquitin/proteasome system has been studied as a target mechanism to optimize adaptation and survival strategies of plants to different environmental stresses. This article aimed at highlighting recent discoveries about the roles ubiquitination may play in the exposure of rice plants to different abiotic stresses, enabling the development of modified plants tolerant to stress. Responses provided by the ubiquitination process include the regulation of the stomatal opening, phytohormones levels, protein stabilization, cell membrane integrity, meristematic cell maintenance, as well as the regulation of reactive oxygen species and heavy metals levels. It is noticeable that ubiquitination is a potential means for developing abiotic stress tolerant plants, being an excellent alternative to rice (and other cultures) improvement programs. PMID:26236935

  4. Inversion analysis of estimating interannual variability and its uncertainties in biotic and abiotic parameters of a parsimonious physiologically based model after wind disturbance

    NASA Astrophysics Data System (ADS)

    Toda, M.; Yokozawa, M.; Richardson, A. D.; Kohyama, T.

    2011-12-01

    The effects of wind disturbance on interannual variability in ecosystem CO2 exchange have been assessed in two forests in northern Japan, i.e., a young, even-aged, monocultured, deciduous forest and an uneven-aged mixed forest of evergreen and deciduous trees, including some over 200 years old using eddy covariance (EC) measurements during 2004-2008. The EC measurements have indicated that photosynthetic recovery of trees after a huge typhoon occurred during early September in 2004 activated annual carbon uptake of both forests due to changes in physiological response of tree leaves during their growth stages. However, little have been resolved about what biotic and abiotic factors regulated interannual variability in heat, water and carbon exchange between an atmosphere and forests. In recent years, an inverse modeling analysis has been utilized as a powerful tool to estimate biotic and abiotic parameters that might affect heat, water and CO2 exchange between the atmosphere and forest of a parsimonious physiologically based model. We conducted the Bayesian inverse model analysis for the model with the EC measurements. The preliminary result showed that the above model-derived NEE values were consistent with observed ones on the hourly basis with optimized parameters by Baysian inversion. In the presentation, we would examine interannual variability in biotic and abiotic parameters related to heat, water and carbon exchange between the atmosphere and forests after disturbance by typhoon.

  5. A Zinc Finger Protein Regulates Flowering Time and Abiotic Stress Tolerance in Chrysanthemum by Modulating Gibberellin Biosynthesis[C][W][OPEN

    PubMed Central

    Yang, Yingjie; Ma, Chao; Xu, Yanjie; Wei, Qian; Imtiaz, Muhammad; Lan, Haibo; Gao, Shan; Cheng, Lina; Wang, Meiyan; Fei, Zhangjun; Hong, Bo; Gao, Junping

    2014-01-01

    Flowering time and an ability to tolerate abiotic stresses are important for plant growth and development. We characterized BBX24, a zinc finger transcription factor gene, from Chrysanthemum morifolium and found it to be associated with both flowering time and stress tolerance. Transgenic lines with suppressed expression of Cm-BBX24 (Cm-BBX24-RNAi) flowered earlier than wild-type plants and showed decreased tolerance to freezing and drought stresses. Global expression analysis revealed that genes associated with both photoperiod and gibberellin (GA) biosynthesis pathways were upregulated in Cm-BBX24-RNAi lines, relative to the wild type. By contrast, genes that were upregulated in overexpressing lines (Cm-BBX24-OX), but downregulated in Cm-BBX24-RNAi lines (both relative to the wild type), included genes related to compatible solutes and carbohydrate metabolism, both of which are associated with abiotic stress. Cm-BBX24 expression was also influenced by daylength and GA4/7 application. Under long days, changes in endogenous GA1, GA4, GA19, and GA20 levels occurred in young leaves of transgenic lines, relative to the wild type. Regulation of flowering involves the FLOWERING TIME gene, which integrates photoperiod and GA biosynthesis pathways. We postulate that Cm-BBX24 plays a dual role, modulating both flowering time and abiotic stress tolerance in chrysanthemum, at least in part by influencing GA biosynthesis. PMID:24858937

  6. Overexpression of the NDR1/HIN1-Like Gene NHL6 Modifies Seed Germination in Response to Abscisic Acid and Abiotic Stresses in Arabidopsis

    PubMed Central

    Pan, Jing; Jiang, Chun-Mei; Srivastava, Renu; Li, Bei; Zhu, Lu-Ying; Su, Hong-Yan; Gao, Xiao-Shu; Liu, Hua; Yu, Xiang; Yang, Lei; Cheng, Xian-Hao; Zhang, Hong-Xia

    2016-01-01

    NHL (NDR1/HIN1-like) genes play crucial roles in pathogen induced plant responses to biotic stress. Here, we report the possible function of NHL6 in plant response to abscisic acid (ABA) and abiotic stress. NHL6 was highly expressed in non-germinated seeds, and its expression was strongly induced by ABA and multiple abiotic stress signals. Loss-of-function of NHL6 decreased sensitivity to ABA in the early developmental stages including seed germination and post-germination seedling growth of the nhl6 mutants. However, overexpression of NHL6 increased sensitivity to ABA, salt and osmotic stress of the transgenic plants. Further studies indicated that the increased sensitivity in the 35S::NHL6 overexpressing plants could be a result of both ABA hypersensitivity and increased endogenous ABA accumulation under the stress conditions. It was also seen that the ABA-responsive element binding factors AREB1, AREB2 and ABF3 could regulate NHL6 expression at transcriptional level. Our results indicate that NHL6 plays an important role in the abiotic stresses-induced ABA signaling and biosynthesis, particularly during seed germination and early seedling development in Arabidopsis. PMID:26849212

  7. Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing soil minerals. 1. Pyrite and magnetite.

    PubMed

    Lee, Woojin; Batchelor, Bill

    2002-12-01

    Abiotic reductive dechlorination of chlorinated ethylenes (tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC)) by pyrite and magnetite was characterized in a batch reactor system. Dechlorination kinetics was adequately described by a modified Langmuir-Hinshelwood model that includes the effect of a decreasing reductive capacity of soil mineral. The kinetic rate constant for the reductive dechlorination of target organics at reactive sites of soil minerals was in the range of 0.185 (+/- 0.023) to 1.71 (+/- 0.06) day(-1). The calculated specific reductive capacity of soil minerals for target organics was in the range of 0.33 (+/- 0.02) to 2.26 (+/- 0.06) microM/g and sorption coefficient was in the range of 0.181 (+/- 0.006) to 0.7 (+/- 0.022) mM(-1). Surface area-normalized pseudo-first-order initial rate constants for target organics by pyrite were found to be 23.5 to 40.3 times greater than those by magnetite. Target organics were mainly transformed to acetylene and small amount of chlorinated intermediates, which suggests that beta-elimination was the main dechlorination pathway. The dechlorination of VC followed a hydrogenolysis pathway to produce ethylene and ethane. The addition of Fe(II) increased the dechlorination rate of cis-DCE and VC in magnetite suspension by nearly a factor of 10. The results obtained in this research provide basic knowledge to better predict the fate of chlorinated ethylenes and to understand the potential of abiotic processes in natural attenuation.

  8. Stress ecology in fucus: abiotic, biotic and genetic interactions.

    PubMed

    Wahl, Martin; Jormalainen, Veijo; Eriksson, Britas Klemens; Coyer, James A; Molis, Markus; Schubert, Hendrik; Dethier, Megan; Karez, Rolf; Kruse, Inken; Lenz, Mark; Pearson, Gareth; Rohde, Sven; Wikström, Sofia A; Olsen, Jeanine L

    2011-01-01

    Stress regimes defined as the synchronous or sequential action of abiotic and biotic stresses determine the performance and distribution of species. The natural patterns of stress to which species are more or less well adapted have recently started to shift and alter under the influence of global change. This was the motivation to review our knowledge on the stress ecology of a benthic key player, the macroalgal genus Fucus. We first provide a comprehensive review of the genus as an ecological model including what is currently known about the major lineages of Fucus species with respect to hybridization, ecotypic differentiation and speciation; as well as life history, population structure and geographic distribution. We then review our current understanding of both extrinsic (abiotic/biotic) and intrinsic (genetic) stress(es) on Fucus species and how they interact with each other. It is concluded that (i) interactive stress effects appear to be equally distributed over additive, antagonistic and synergistic categories at the level of single experiments, but are predominantly additive when averaged over all studies in a meta-analysis of 41 experiments; (ii) juvenile and adult responses to stress frequently differ and (iii) several species or particular populations of Fucus may be relatively unaffected by climate change as a consequence of pre-adapted ecotypes that collectively express wide physiological tolerences. Future research on Fucus should (i) include additional species, (ii) include marginal populations as models for responses to environmental stress; (iii) assess a wider range of stress combinations, including their temporal fluctuations; (iv) better differentiate between stress sensitivity of juvenile versus adult stages; (v) include a functional genomic component in order to better integrate Fucus' ecological and evolutionary responses to stress regimes and (vi) utilize a multivariate modelling approach in order to develop and understand interaction

  9. Regulatory roles of serotonin and melatonin in abiotic stress tolerance in plants

    PubMed Central

    Kaur, Harmeet; Mukherjee, Soumya; Baluska, Frantisek; Bhatla, Satish C

    2015-01-01

    Understanding the physiological and biochemical basis of abiotic stress tolerance in plants has always been one of the major aspects of research aiming to enhance plant productivity in arid and semi-arid cultivated lands all over the world. Growth of stress-tolerant transgenic crops and associated agricultural benefits through increased productivity, and related ethical issues, are also the major concerns of current research in various laboratories. Interesting data on the regulation of abiotic stress tolerance in plants by serotonin and melatonin has accumulated in the recent past. These two indoleamines possess antioxidative and growth-inducing properties, thus proving beneficial for stress acclimatization. Present review shall focus on the modes of serotonin and melatonin-induced regulation of abiotic stress tolerance in plants. Complex molecular interactions of serotonin and auxin-responsive genes have suggested their antagonistic nature. Data from genomic and metabolomic analyses of melatonin-induced abiotic stress signaling have lead to an understanding of the regulation of stress tolerance through the modulation of transcription factors, enzymes and various signaling molecules. Melatonin, nitric oxide (NO) and calmodulin interactions have provided new avenues for research on the molecular aspects of stress physiology in plants. Investigations on the characterization of receptors associated with serotonin and melatonin responses, are yet to be undertaken in plants. Patenting of biotechnological inventions pertaining to serotonin and melatonin formulations (through soil application or foliar spray) are expected to be some of the possible ways to regulate abiotic stress tolerance in plants. The present review, thus, summarizes the regulatory roles of serotonin and melatonin in modulating the signaling events accompanying abiotic stress in plants. PMID:26633566

  10. Regulatory roles of serotonin and melatonin in abiotic stress tolerance in plants.

    PubMed

    Kaur, Harmeet; Mukherjee, Soumya; Baluska, Frantisek; Bhatla, Satish C

    2015-01-01

    Understanding the physiological and biochemical basis of abiotic stress tolerance in plants has always been one of the major aspects of research aiming to enhance plant productivity in arid and semi-arid cultivated lands all over the world. Growth of stress-tolerant transgenic crops and associated agricultural benefits through increased productivity, and related ethical issues, are also the major concerns of current research in various laboratories. Interesting data on the regulation of abiotic stress tolerance in plants by serotonin and melatonin has accumulated in the recent past. These two indoleamines possess antioxidative and growth-inducing properties, thus proving beneficial for stress acclimatization. Present review shall focus on the modes of serotonin and melatonin-induced regulation of abiotic stress tolerance in plants. Complex molecular interactions of serotonin and auxin-responsive genes have suggested their antagonistic nature. Data from genomic and metabolomic analyses of melatonin-induced abiotic stress signaling have lead to an understanding of the regulation of stress tolerance through the modulation of transcription factors, enzymes and various signaling molecules. Melatonin, nitric oxide (NO) and calmodulin interactions have provided new avenues for research on the molecular aspects of stress physiology in plants. Investigations on the characterization of receptors associated with serotonin and melatonin responses, are yet to be undertaken in plants. Patenting of biotechnological inventions pertaining to serotonin and melatonin formulations (through soil application or foliar spray) are expected to be some of the possible ways to regulate abiotic stress tolerance in plants. The present review, thus, summarizes the regulatory roles of serotonin and melatonin in modulating the signaling events accompanying abiotic stress in plants.

  11. Temporal dynamics of biotic and abiotic drivers of litter decomposition.

    PubMed

    García-Palacios, Pablo; Shaw, E Ashley; Wall, Diana H; Hättenschwiler, Stephan

    2016-05-01

    Climate, litter quality and decomposers drive litter decomposition. However, little is known about whether their relative contribution changes at different decomposition stages. To fill this gap, we evaluated the relative importance of leaf litter polyphenols, decomposer communities and soil moisture for litter C and N loss at different stages throughout the decomposition process. Although both microbial and nematode communities regulated litter C and N loss in the early decomposition stages, soil moisture and legacy effects of initial differences in litter quality played a major role in the late stages of the process. Our results provide strong evidence for substantial shifts in how biotic and abiotic factors control litter C and N dynamics during decomposition. Taking into account such temporal dynamics will increase the predictive power of decomposition models that are currently limited by a single-pool approach applying control variables uniformly to the entire decay process.

  12. Electrode impedance analysis of chronic tungsten microwire neural implants: understanding abiotic vs. biotic contributions

    PubMed Central

    Sankar, Viswanath; Patrick, Erin; Dieme, Robert; Sanchez, Justin C.; Prasad, Abhishek; Nishida, Toshikazu

    2014-01-01

    Changes in biotic and abiotic factors can be reflected in the complex impedance spectrum of the microelectrodes chronically implanted into the neural tissue. The recording surface of the tungsten electrode in vivo undergoes abiotic changes due to recording site corrosion and insulation delamination as well as biotic changes due to tissue encapsulation as a result of the foreign body immune response. We reported earlier that large changes in electrode impedance measured at 1 kHz were correlated with poor electrode functional performance, quantified through electrophysiological recordings during the chronic lifetime of the electrode. There is a need to identity the factors that contribute to the chronic impedance variation. In this work, we use numerical simulation and regression to equivalent circuit models to evaluate both the abiotic and biotic contributions to the impedance response over chronic implant duration. COMSOL® simulation of abiotic electrode morphology changes provide a possible explanation for the decrease in the electrode impedance at long implant duration while biotic changes play an important role in the large increase in impedance observed initially. PMID:24847248

  13. WRKY Proteins: Signaling and Regulation of Expression during Abiotic Stress Responses

    PubMed Central

    Banerjee, Aditya

    2015-01-01

    WRKY proteins are emerging players in plant signaling and have been thoroughly reported to play important roles in plants under biotic stress like pathogen attack. However, recent advances in this field do reveal the enormous significance of these proteins in eliciting responses induced by abiotic stresses. WRKY proteins act as major transcription factors, either as positive or negative regulators. Specific WRKY factors which help in the expression of a cluster of stress-responsive genes are being targeted and genetically modified to induce improved abiotic stress tolerance in plants. The knowledge regarding the signaling cascade leading to the activation of the WRKY proteins, their interaction with other proteins of the signaling pathway, and the downstream genes activated by them are altogether vital for justified targeting of the WRKY genes. WRKY proteins have also been considered to generate tolerance against multiple abiotic stresses with possible roles in mediating a cross talk between abiotic and biotic stress responses. In this review, we have reckoned the diverse signaling pattern and biological functions of WRKY proteins throughout the plant kingdom along with the growing prospects in this field of research. PMID:25879071

  14. Jasmonate signaling in plant development and defense response to multiple (a)biotic stresses.

    PubMed

    Santino, Angelo; Taurino, Marco; De Domenico, Stefania; Bonsegna, Stefania; Poltronieri, Palmiro; Pastor, Victoria; Flors, Victor

    2013-07-01

    Plants frequently live in environments characterized by the presence of simultaneous and different stresses. The intricate and finely tuned molecular mechanisms activated by plants in response to abiotic and biotic environmental factors are not well understood, and less is known about the integrative signals and convergence points activated by plants in response to multiple (a)biotic stresses. Phytohormones play a key role in plant development and response to (a)biotic stresses. Among these, one of the most important signaling molecules is an oxylipin, the plant hormone jasmonic acid. Oxylipins are derived from oxygenation of polyunsaturated fatty acids. Jasmonic acid and its volatile derivative methyl jasmonate have been considered for a long time to be the bioactive forms due to their physiological effects and abundance in the plant. However, more recent studies showed unambiguously that they are only precursors of the active forms represented by some amino acid conjugates. Upon developmental or environmental stimuli, jasmonates are synthesized and accumulate transiently. Upon perception, jasmonate signal transduction process is finely tuned by a complex mechanism comprising specific repressor proteins which in turn control a number of transcription factors regulating the expression of jasmonate responsive genes. We discuss the latest discoveries about the role of jasmonates in plants resistance mechanism against biotic and abiotic stresses. Finally, the deep interplay of different phytohormones in stresses signaling will be also discussed.

  15. Overexpression of wheat ubiquitin gene, Ta-Ub2, improves abiotic stress tolerance of Brachypodium distachyon.

    PubMed

    Kang, Hanhan; Zhang, Meng; Zhou, Shumei; Guo, Qifang; Chen, Fengjuan; Wu, Jiajie; Wang, Wei

    2016-07-01

    Ubiquitination plays an important role in regulating plant's development and adaptability to abiotic stress. To investigate the possible functions of a wheat monoubiquitin gene Ta-Ub2 in abiotic stress in monocot and compare it with that in dicot, we generated transgenic Brachypodium plants overexpressing Ta-Ub2 under the control of CaMV35s and stress-inducible RD29A promoters. The constitutive expression of Ta-Ub2 displayed slight growth inhibition in the growth of transgenic Brachypodium distachyon under the control conditions. However, this inhibition was minimized by expression of Ta-Ub2 under the control of stress-inducible RD29A promoter. Compared with WT, the transgenic plants preserved more water and showed higher enzymatic antioxidants under drought stress, which might be related to the change in the expression of some antioxidant genes. The expression of C-repeat binding factors transcription factor genes in the transgenic B. distachyon lines were upregulated under water stress. Salt and cold tolerances of transgenic B. distachyon were also improved. Although the phenotypic changes in the transgenic plants were different, overexpression of Ta-Ub2 improved the abiotic stress tolerance in both dicot and monocot plants. The improvement in Ta-Ub2 transgenic plants in abiotic stress tolerance might be, at least partly, through regulating the gene expression and increasing the enzymatic antioxidants.

  16. Abiotic Transformation Of Estrogens In Synthetic Municipal Wastewater: An Alternative For Treatment?

    EPA Science Inventory

    The abiotic transformation of estrogens, including estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2), in the presence of model vegetable matter was confirmed in this study. Batch experiments were performed to model the catalytic conversion of E1, E2, E3, and ...

  17. Erosion rates, stochasticity, and abiotic vs. biotic bedrock to soil production mechanisms in the Oregon Coast Range

    NASA Astrophysics Data System (ADS)

    Marshall, J. A.; Roering, J. J.

    2010-12-01

    On hillslopes, abiotic and biotic processes advance conversion of bedrock to soil, accelerate exposure of newly created soil to weathering processes, and facilitate sediment transport. Despite recent gains in characterizing soil production laws in steady state landscapes, little empirical data exists on spatial variability in production styles or the relative importance of biotic and abiotic controls on bedrock to soil conversion on soil-mantled slopes. In settings subject to stochastic ‘macro’ disturbances, such as tree growth and turnover, local topography vs. soil-depth relationships provide limited insight into soil production mechanisms. Here we present soil depth data and observations on production mechanisms from hillslopes with slow, intermediate, and fast erosion rates (inferred by hilltop convexity or curvature). Due to the stochastic nature of soil production, we characterize the spatial pattern of soil depth over a broad ridgeline area assuming that the erosion rate does not vary significantly across the ridge. To test our hypothesis that bedrock to soil conversion is variable due to stochastic production mechanisms in rapidly eroding terrain and less variable in slower eroding catchments, we dug over 60 pits and quantified depth to bedrock and abiotic weathering mechanisms. Conjointly, we hypothesize that a number of factors control bedrock to soil conversion including: a) bedrock fracture-controlled tree spacing in very thin soils, b) presence or absence of pit and mound topography, c) root-bedrock interactions, and d) diverse abiotic physical weathering mechanisms. To quantify potential controls on variability, we measured: a) location and size of old growth Pseudotsuga menziesii (Douglas fir) stumps, b) rooting depths, and c) clast dimension ratios (to distinguish between weathering mechanisms). We find a negative correlation between average soil depth and hillslope convexity, while the coefficient of variation increases with increasing

  18. Oncostatin M is a member of a cytokine family that includes leukemia-inhibitory factor, granulocyte colony-stimulating factor, and interleukin 6.

    PubMed Central

    Rose, T M; Bruce, A G

    1991-01-01

    Oncostatin M (OSM), a glycoprotein of Mr approximately 28,000 produced by activated monocyte and T-lymphocyte cell lines, was previously identified by its ability to inhibit the growth of cells from melanoma and other solid tumors. We have detected significant similarities in the primary amino acid sequences and predicted secondary structures of OSM, leukemia-inhibitory factor (LIF), granulocyte colony-stimulating factor (G-CSF), and interleukin 6 (IL-6). Analysis of the genes encoding these proteins revealed a shared exon organization, suggesting evolutionary descent from a common ancestral gene. Using a panel of DNAs from somatic cell hybrids, we have shown that OSM, like LIF, is located on human chromosome 22. We have also demonstrated that OSM has the ability to inhibit the proliferation of murine M1 myeloid leukemic cells and can induce their differentiation into macrophage-like cells, a function shared by LIF, G-CSF, and IL-6. We propose that OSM, LIF, G-CSF, and IL-6 are structurally related members of a cytokine family that have in common the ability to modulate differentiation of a variety of cell types. Images PMID:1717982

  19. Selection of Reliable Reference Genes for Gene Expression Analysis under Abiotic Stresses in the Desert Biomass Willow, Salix psammophila

    PubMed Central

    Li, Jianbo; Jia, Huixia; Han, Xiaojiao; Zhang, Jin; Sun, Pei; Lu, Mengzhu; Hu, Jianjun

    2016-01-01

    Salix psammophila is a desert shrub willow that has extraordinary adaptation to abiotic stresses and plays an important role in maintaining local ecosystems. Moreover, S. psammophila is regarded as a promising biomass feedstock because of its high biomass yields and short rotation coppice cycle. However, few suitable reference genes (RGs) for quantitative real-time polymerase chain reaction (qRT-PCR) constrain the study on normalization of gene expression in S. psammophila until now. Here, we investigated the expression stabilities of 14 candidate RGs across tissue types and under four abiotic stress treatments, including heat, cold, salt, and drought treatments. After calculation of PCR efficiencies, three different software, NormFinder, geNorm, and BestKeeper were employed to analyze systematically the qRT-PCR data, and the outputs were merged by RankAggreg software. The optimal RGs selected for gene expression analysis were EF1α (Elongation factor-1 alpha) and OTU (OTU-like cysteine protease family protein) for different tissue types, UBC (Ubiquitin-conjugating enzyme E2) and LTA4H (Leukotriene A-4 hydrolase homolog) for heat treatment, HIS (Histone superfamily protein H3) and ARF2 (ADP-ribosylation factor 2) for cold treatment, OTU and ACT7 (Actin 7) for salt treatment, UBC and LTA4H for drought treatment. The expression of UBC, ARF2, and VHAC (V-type proton ATPase subunit C) varied the least across tissue types and under abiotic stresses. Furthermore, the relative genes expression profiles of one tissue-specific gene WOX1a (WUSCHEL-related homeobox 1a), and four stress-inducible genes, including Hsf-A2 (Heat shock transcription factors A2), CBF3 (C-repeat binding factor 3), HKT1 (High-Affinity K+ Transporter 1), and GST (Glutathione S-transferase), were conducted to confirm the validity of the RGs in this study. These results provided an important RGs application guideline for gene expression characterization in S. psammophila. PMID:27761137

  20. Abiotic dechlorination in rock matrices impacted by long-term exposure to TCE.

    PubMed

    Schaefer, Charles E; Towne, Rachael M; Lippincott, David R; Lacombe, Pierre J; Bishop, Michael E; Dong, Hailiang

    2015-01-01

    Field and laboratory tests were performed to evaluate the abiotic reaction of trichloroethene (TCE) in sedimentary rock matrices. Hydraulically conductive fractures, and the rock directly adjacent to the hydraulically conductive fractures, within a historically contaminated TCE bedrock aquifer were used as the basis for this study. These results were compared to previous work using rock that had not been exposed to TCE (Schaefer et al., 2013) to assess the impact of long-term TCE exposure on the abiotic dechlorination reaction, as the longevity of these reactions after long-term exposure to TCE was hitherto unknown. Results showed that potential abiotic TCE degradation products, including ethane, ethene, and acetylene, were present in the conductive fractures. Using minimally disturbed slices of rock core at and near the fracture faces, laboratory testing on the rocks confirmed that abiotic dechlorination reactions between the rock matrix and TCE were occurring. Abiotic daughter products measured in the laboratory under controlled conditions were consistent with those measured in the conductive fractures, except that propane also was observed as a daughter product. TCE degradation measured in the laboratory was well described by a first order rate constant through the 118-d study. Observed bulk first-order TCE degradation rate constants within the rock matrix were 1.3×10(-8) s(-1). These results clearly show that abiotic dechlorination of TCE is occurring within the rock matrix, despite decades of exposure to TCE. Furthermore, these observed rates of TCE dechlorination are expected to have a substantial impact on TCE migration and uptake/release from rock matrices.

  1. Increased growth in sunflower correlates with reduced defences and altered gene expression in response to biotic and abiotic stress.

    PubMed

    Mayrose, Maya; Kane, Nolan C; Mayrose, Itay; Dlugosch, Katrina M; Rieseberg, Loren H

    2011-11-01

    Cultivated plants have been selected by humans for increased yield in a relatively benign environment, where nutrient and water resources are often supplemented, and biotic enemy loads are kept artificially low. Agricultural weeds have adapted to this same benign environment as crops and often have high growth and reproductive rates, even though they have not been specifically selected for yield. Considering the competing demands for resources in any plant, a key question is whether adaptation to agricultural environments has been accompanied by life history trade-offs, in which resistance to (largely absent) stress has been lost in favour of growth and reproduction. The experiments reported here were designed to test for growth-defence trade-offs in agricultural weeds, crops and native varieties of common sunflower (Helianthus annuus L., Asteraceae) by comparing their performance in the presence or absence of abiotic (drought and crowding) or biotic (simulated herbivory, insect herbivory and fungal) stress. We found that growth, as well as viability of crops and weeds, was reduced by abiotic drought stress. The weakened defence in the agricultural genotypes was further evident as increased susceptibility to fungal infection and higher level of insect palatability. To uncover molecular mechanisms underlying these trade-offs, we monitored gene expression kinetics in drought-stressed plants. By correlating phenotypic observations with molecular analyses, we report the identification of several genes, including a protein phosphatase 2C and the HD-Zip transcription factor Athb-8, whose expression is associated with the observed phenotypic variation in common sunflower.

  2. Abiotic Methane Synthesis: Caveats and New Results

    NASA Astrophysics Data System (ADS)

    Zou, R.; Sharma, A.

    2005-12-01

    The role of mineral interaction with geochemical fluids under hydrothermal conditions has invoked models of geochemical synthesis of organic molecules at deep crustal conditions. Since Thomas Gold's (1992) hypothesis of the possibility of an abiotic organic synthesis, there have been several reports of hydrocarbon formation under high pressure and temperature conditions. Several previous experimental studies have recognized that small amounts of methane (and other light HC compounds) can be synthesized via catalysis by transition metals: Fe, Ni (Horita and Berndt, 1999 Science) and Cr (Foustavous and Seyfried, 2004 Science). In light of these pioneering experiments, an investigation of the feasibility of abiotic methane synthesis at higher pressure conditions in deep geological setting and the possible role of catalysis warrants a closer look. We conducted three sets of experiments in hydrothermal diamond anvil cell using FeO nanopowder, CaCO 3 and water at 300° - 600° C and 0.5 - 5 GPa : (a) with stainless steel gasket, (b) gold-lined gasket, and (c) gold-lined gasket with added Fe and Ni nanopowder. The reactions were monitored in-situ using micro-Raman spectroscopy with 532nm and 632nm lasers. The solids phases were characterized in-situ using synchrotron X-ray diffraction at CHESS-Cornell and quenched products with an electron microprobe. Interestingly, a variable amount of hydrocarbon was observed only in runs with stainless steel gasket and with Fe, Ni nanoparticles. Experiments with gold-lined reactors did not show any hydrocarbon formation. Added high resolution microscopy of the products and their textural relationship within the diamond cell with Raman spectroscopy data show that the hydrocarbon (methane and other light fractions) synthesis is a direct result of transition metal catalysis, rather than wustite - calcium carbonate reaction as recently reported by Scott et al (2004, PNAS). The author will further present new results highlighting abiotic

  3. Generation of RNA in abiotic conditions.

    NASA Astrophysics Data System (ADS)

    di Mauro, Ernesto

    Generation of RNA in abiotic conditions. Ernesto Di Mauro Dipartimento di Genetica Bi-ologia Molecolare, Universit` "Sapienza" Roma, Italy. a At least four conditions must be satisfied for the spontaneous generation of (pre)-genetic poly-mers: 1) availability of precursors that are activated enough to spontaneously polymerize. Preliminary studies showed that (a) nucleic bases and acyclonucleosides can be synthesized from formamide H2NCOH by simply heating with prebiotically available mineral catalysts [last reviewed in (1)], and that b) nucleic bases can be phosphorylated in every possible posi-tion [2'; 3'; 5'; cyclic 2',3'; cyclic 3',5' (2)]. The higher stability of the cyclic forms allows their accumulation. 2) A polymerization mechanism. A reaction showing the formation of RNA polymers starting from prebiotically plausible precursors (3',5' cyclic GMP and 3', 5'cyclic AMP) was recently reported (3). Polymerization in these conditions is thermodynamically up-hill and an equilibrium is attained that limits the maximum length of the polymer produced to about 40 nucleotides for polyG and 100 nucleotides for polyA. 3) Ligation of the synthesized oligomers. If this type of reaction could occur according to a terminal-joining mechanism and could generate canonical 3',5' phosphodiester bonds, exponential growth would be obtained of the generated oligomers. This type of reaction has been reported (4) , limited to homogeneous polyA sequences and leading to the production of polyA dimers and tetramers. What is still missing are: 4) mechanisms that provide the proof of principle for the generation of sequence complexity. We will show evidence for two mechanisms providing this proof of principle for simple complementary sequences. Namely: abiotic sequence complementary-driven terminal ligation and sequence-complementary terminal growth. In conclusion: all the steps leading to the generation of RNA in abiotic conditions are satisfied. (1) R Saladino, C Crestini, F

  4. Evaluation of abiotic fate mechanisms in soil slurry bioreactor treatment

    SciTech Connect

    Glaser, J.A.; McCauley, P.T.; Dosani, M.A.

    1995-10-01

    Biological treatment of contaminated soil slurries may offer a viable technology for soil bioremediation. Slurry bioreactor treatment of soils, however, has not sufficiently progressed to be a durable, reliable, and cost-effective treatment option. Critical to the evaluation of slurry bioreactors is a better description of pollutant mass transfer during the treatment phase. Losses attributable to abiotic means are generally overlooked in field application of the technology. Discussions with EPA regional personnel and inspection of active soil slurry bioreactor operations have identified operational problems such as foaming which could result in possible abiotic loss. Field bioslurry operations have adopted various approaches to reduce foaming: (1) the addition of defoaming agents, (2) the reduction of rotational speed of the agitator, and (3) the reduction of gas flow through the bioreactor system. We have conducted two bench-scale slurry bioreactor treatability studies, at the U.S. EPA Testing & Evaluation Facility in Cincinnati, Ohio, which were designed to investigate some of the operating factors leading to foam formation and identify the most advantageous means to deal with foaming. The initial study has been previously presented as a general treatability study for treatment of creosote contamination in a soil. During this study, foaming became a major problem for operation. The foaming conditions were mitigated by use of defoamer and, in the more extreme cases, through reduction of the mixer rotational speed and gas flow. A subsequent study which was devoted specifically to investigating the causes and conditions of foaming using a different batch of soil from the same site as the earlier study showed little foaming at the very beginning of the study.

  5. Factors determining the distribution and abundance of Dreissena polymorpha in lakes, dam reserviors and channels

    SciTech Connect

    Karatayev, A.

    1995-06-01

    This article addresses the several factors affecting the distribution and abundance of Dreissena polymorphia in bodies of water. Factors covered include: (1) salinity, (2) oxygen level, (3) temperature, (4) substrate, (5) depth, and (6) water chemistry. The analysis of the data allowed the specification of limiting or optimal concentrations of the principle abiotic parameters.

  6. Cell wall remodeling under abiotic stress

    PubMed Central

    Tenhaken, Raimund

    2015-01-01

    Plants exposed to abiotic stress respond to unfavorable conditions on multiple levels. One challenge under drought stress is to reduce shoot growth while maintaining root growth, a process requiring differential cell wall synthesis and remodeling. Key players in this process are the formation of reactive oxygen species (ROS) and peroxidases, which initially cross-link phenolic compounds and glycoproteins of the cell walls causing stiffening. The function of ROS shifts after having converted all the peroxidase substrates in the cell wall. If ROS-levels remain high during prolonged stress, OH°-radicals are formed which lead to polymer cleavage. In concert with xyloglucan modifying enzymes and expansins, the resulting cell wall loosening allows further growth of stressed organs. PMID:25709610

  7. Abiotic formation of oligonucleotides on basalt surfaces

    NASA Astrophysics Data System (ADS)

    Otroshchenko, V. A.; Vasilyeva, N. V.; Kopilov, A. M.

    1985-06-01

    The complication and further evolution of abiotic syntheses products occurred under environmental influences at the prebiological stage. From this point of view, the influence of some types of irradiation on the organic molecules adsorbed on the surfaces of volcanic rocks, appeared to be of great importance. In this connection, the effect of gamma rays on the AMP molecules adsorbed on mineral surfaces such as cinders and ashes has been studied. It has been shown that they can polymerize with the formation of oligonucleotides. The treatment of oligomers obtained by venom phosphodiesterase has shown that a polymeric product has mainly 3' 5' and 2' 5' bonds between nucleotides. The results obtained have been discussed from the evolutionary aspect.

  8. Form and function of grass ring patterns in arid grasslands: the role of abiotic controls.

    PubMed

    Ravi, Sujith; D'Odorico, Paolo; Wang, Lixin; Collins, Scott

    2008-12-01

    Ring-shaped growth patterns commonly occur in resource-limited arid and semi-arid environments. The spatial distribution, geometry, and scale of vegetation growth patterns result from interactions between biotic and abiotic processes, and, in turn, affect the spatial patterns of soil moisture, sediment transport, and nutrient dynamics in aridland ecosystems. Even though grass ring patterns are observed worldwide, a comprehensive understanding of the biotic and abiotic processes that lead to the formation, growth and breakup of these rings is still lacking. Our studies on patterns of infiltration and soil properties of blue grama (Bouteloua gracilis) grass rings in the northern Chihuahuan desert indicate that ring patterns result from the interaction between clonal growth mechanisms and abiotic factors such as hydrological and aeolian processes. These processes result in a negative feedback between sediment deposition and vegetation growth inside the bunch grass, which leads to grass die back at the center of the grass clump. We summarize these interactions in a simple theoretical and conceptual model that integrates key biotic and abiotic processes in ring formation, growth and decline.

  9. Sterility Caused by Floral Organ Degeneration and Abiotic Stresses in Arabidopsis and Cereal Grains

    PubMed Central

    Smith, Ashley R.; Zhao, Dazhong

    2016-01-01

    Natural floral organ degeneration or abortion results in unisexual or fully sterile flowers, while abiotic stresses lead to sterility after initiation of floral reproductive organs. Since normal flower development is essential for plant sexual reproduction and crop yield, it is imperative to have a better understanding of plant sterility under regular and stress conditions. Here, we review the functions of ABC genes together with their downstream genes in floral organ degeneration and the formation of unisexual flowers in Arabidopsis and several agriculturally significant cereal grains. We further explore the roles of hormones, including auxin, brassinosteroids, jasmonic acid, gibberellic acid, and ethylene, in floral organ formation and fertility. We show that alterations in genes affecting hormone biosynthesis, hormone transport and perception cause loss of stamens/carpels, abnormal floral organ development, poor pollen production, which consequently result in unisexual flowers and male/female sterility. Moreover, abiotic stresses, such as heat, cold, and drought, commonly affect floral organ development and fertility. Sterility is induced by abiotic stresses mostly in male floral organ development, particularly during meiosis, tapetum development, anthesis, dehiscence, and fertilization. A variety of genes including those involved in heat shock, hormone signaling, cold tolerance, metabolisms of starch and sucrose, meiosis, and tapetum development are essential for plants to maintain normal fertility under abiotic stress conditions. Further elucidation of cellular, biochemical, and molecular mechanisms about regulation of fertility will improve yield and quality for many agriculturally valuable crops. PMID:27790226

  10. Abiotic Organic Chemistry in Hydrothermal Systems.

    NASA Astrophysics Data System (ADS)

    Simoneit, B. R.; Rushdi, A. I.

    2004-12-01

    Abiotic organic chemistry in hydrothermal systems is of interest to biologists, geochemists and oceanographers. This chemistry consists of thermal alteration of organic matter and minor prebiotic synthesis of organic compounds. Thermal alteration has been extensively documented to yield petroleum and heavy bitumen products from contemporary organic detritus. Carbon dioxide, carbon monoxide, ammonia and sulfur species have been used as precursors in prebiotic synthesis experiments to organic compounds. These inorganic species are common components of hot spring gases and marine hydrothermal systems. It is of interest to further test their reactivities in reductive aqueous thermolysis. We have synthesized organic compounds (lipids) in aqueous solutions of oxalic acid, and with carbon disulfide or ammonium bicarbonate at temperatures from 175-400° C. The synthetic lipids from oxalic acid solutions consisted of n-alkanols, n-alkanoic acids, n-alkyl formates, n-alkanones, n-alkenes and n-alkanes, typically to C30 with no carbon number preferences. The products from CS2 in acidic aqueous solutions yielded cyclic thioalkanes, alkyl polysulfides, and thioesters with other numerous minor compounds. The synthesis products from oxalic acid and ammonium bicarbonate solutions were homologous series of n-alkyl amides, n-alkyl amines, n-alkanes and n-alkanoic acids, also to C30 with no carbon number predominance. Condensation (dehydration) reactions also occur under elevated temperatures in aqueous medium as tested by model reactions to form amide, ester and nitrile bonds. It is concluded that the abiotic formation of aliphatic lipids, condensation products (amides, esters, nitriles, and CS2 derivatives (alkyl polysulfides, cyclic polysulfides) is possible under hydrothermal conditions and warrants further studies.

  11. ABIOTIC IN SITU TECHNOLOGIES FOR GROUNDWATER REMEDIATION CONFERENCE: PROCEEDINGS

    EPA Science Inventory

    The USEPA conference on Abiotic In Situ Technologies for Groundwater Remediation was held in Dallas, TX, 8/31-9/2/99. The goal of the meeting was to disseminate current information on abiotic in situ groundwater treatment echnologies. Although much information is being provided a...

  12. Abiotic Formation of Methyl Halides in the Terrestrial Environment

    NASA Astrophysics Data System (ADS)

    Keppler, F.

    2011-12-01

    Methyl chloride and methyl bromide are the most abundant chlorine and bromine containing organic compounds in the atmosphere. Since both compounds have relatively long tropospheric lifetimes they can effectively transport halogen atoms from the Earth's surface, where they are released, to the stratosphere and following photolytic oxidation form reactive halogen gases that lead to the chemical destruction of ozone. Methyl chloride and methyl bromide account for more than 20% of the ozone-depleting halogens delivered to the stratosphere and are predicted to grow in importance as the chlorine contribution to the stratosphere from anthropogenic CFCs decline. Today methyl chloride and methyl bromide originate mainly from natural sources with only a minor fraction considered to be of anthropogenic origin. However, until as recently as 2000 most of the methyl chloride and methyl bromide input to the atmosphere was considered to originate from the oceans, but investigations in recent years have clearly demonstrated that terrestrial sources such as biomass burning, wood-rotting fungi, coastal salt marshes, tropical vegetation and organic matter degradation must dominate the atmospheric budgets of these trace gases. However, many uncertainties still exist regarding strengths of both sources and sinks, as well as the mechanisms of formation of these naturally occurring halogenated gases. A better understanding of the atmospheric budget of both methyl chloride and methyl bromide is therefore required for reliable prediction of future ozone depletion. Biotic and abiotic methylation processes of chloride and bromide ion are considered to be the dominant pathways of formation of these methyl halides in nature. In this presentation I will focus on abiotic formation processes in the terrestrial environment and the potential parameters that control their emissions. Recent advances in our understanding of the abiotic formation pathway of methyl halides will be discussed. This will

  13. Autophagy, a Conserved Mechanism for Protein Degradation, Responds to Heat, and Other Abiotic Stresses in Capsicum annuum L.

    PubMed Central

    Zhai, Yufei; Guo, Meng; Wang, Hu; Lu, Jinping; Liu, Jinhong; Zhang, Chong; Gong, Zhenhui; Lu, Minghui

    2016-01-01

    Abiotic stresses negatively affect plants growth and development by inducing protein denaturation, and autophagy degrades the damaged proteins to alleviate their toxicity, however, little is known about the involvement of autophagy in pepper (Capsicum annuum L.) tolerances to abiotic stresses. In this study, we identified autophagy-related gene (ATG) members in the whole genome of pepper by HMM method and analyzed their expression profiles in response to heat and other abiotic stresses by quantitative real-time PCR. The results showed that the CaATG contained 15 core ATG members including 29 ATG proteins with their respective conserved functional domains, involving the whole process of autophagy. Under normal environmental condition, the expression of CaATG genes showed tissue- and developmental stage-specific patterns, while under abiotic stresses of salt, drought, heat, cold and carbohydrate starvation, the accumulation of autophagosome punctate increased and the expression level of CaATG genes changed with stress type-dependent pattern, which indicates the linkage of autophagy in pepper response to abiotic stresses. After treated with heat stress, both the number of up-regulated CaATG genes and the increment of autophagosome punctate were higher in pepper thermotolerant line R9 than those in thermosensitive line B6, implying an association of autophagy with heat tolerance. In addition, CaATG6 was predicted to interact with CaHSP90 family members. Our study suggests that autophagy is connected to pepper tolerances to heat and other abiotic stresses. PMID:26904087

  14. Unveiling the Redox Control of Plant Reproductive Development during Abiotic Stress

    PubMed Central

    Zinta, Gaurav; Khan, Asif; AbdElgawad, Hamada; Verma, Vipasha; Srivastava, Ashish Kumar

    2016-01-01

    Plants being sessile in nature are often challenged to various abiotic stresses including temperature fluctuations, water supply, salinity, and nutrient availability. Exposure of plants to such environmental perturbations result in the formation of reactive oxygen species (ROS) in cells. To scavenge ROS, enzymatic and molecular antioxidants are produced at a cellular level. ROS act as a signaling entity at lower concentrations maintaining normal growth and development, but if their levels increase beyond certain threshold, they produce toxic effects in plants. Some developmental stages, such as development of reproductive organs are more sensitive to abiotic stress than other stages of growth. As success of plant reproductive development is directly correlated with grain yield, stresses coinciding with reproductive phase results in the higher yield losses. In this article, we summarize the redox control of plant reproductive development, and elaborate how redox homeostasis is compromised during abiotic stress exposure. We highlight why more emphasis should be given to understand redox control of plant reproductive organ development during abiotic stress exposure96to engineer crops with better crop yield. We specifically discuss the role of ROS as a signaling molecule and its cross-talk with other signaling molecules such as hormones and sugars. PMID:27379102

  15. Mass spectrometry-based plant metabolomics: Metabolite responses to abiotic stress.

    PubMed

    Jorge, Tiago F; Rodrigues, João A; Caldana, Camila; Schmidt, Romy; van Dongen, Joost T; Thomas-Oates, Jane; António, Carla

    2016-09-01

    Metabolomics is one omics approach that can be used to acquire comprehensive information on the composition of a metabolite pool to provide a functional screen of the cellular state. Studies of the plant metabolome include analysis of a wide range of chemical species with diverse physical properties, from ionic inorganic compounds to biochemically derived hydrophilic carbohydrates, organic and amino acids, and a range of hydrophobic lipid-related compounds. This complexitiy brings huge challenges to the analytical technologies employed in current plant metabolomics programs, and powerful analytical tools are required for the separation and characterization of this extremely high compound diversity present in biological sample matrices. The use of mass spectrometry (MS)-based analytical platforms to profile stress-responsive metabolites that allow some plants to adapt to adverse environmental conditions is fundamental in current plant biotechnology research programs for the understanding and development of stress-tolerant plants. In this review, we describe recent applications of metabolomics and emphasize its increasing application to study plant responses to environmental (stress-) factors, including drought, salt, low oxygen caused by waterlogging or flooding of the soil, temperature, light and oxidative stress (or a combination of them). Advances in understanding the global changes occurring in plant metabolism under specific abiotic stress conditions are fundamental to enhance plant fitness and increase stress tolerance. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 35:620-649, 2016.

  16. MicroRNAs As Potential Targets for Abiotic Stress Tolerance in Plants

    PubMed Central

    Shriram, Varsha; Kumar, Vinay; Devarumath, Rachayya M.; Khare, Tushar S.; Wani, Shabir H.

    2016-01-01

    The microRNAs (miRNAs) are small (20–24 nt) sized, non-coding, single stranded riboregulator RNAs abundant in higher organisms. Recent findings have established that plants assign miRNAs as critical post-transcriptional regulators of gene expression in sequence-specific manner to respond to numerous abiotic stresses they face during their growth cycle. These small RNAs regulate gene expression via translational inhibition. Usually, stress induced miRNAs downregulate their target mRNAs, whereas, their downregulation leads to accumulation and function of positive regulators. In the past decade, investigations were mainly aimed to identify plant miRNAs, responsive to individual or multiple environmental factors, profiling their expression patterns and recognizing their roles in stress responses and tolerance. Altered expressions of miRNAs implicated in plant growth and development have been reported in several plant species subjected to abiotic stress conditions such as drought, salinity, extreme temperatures, nutrient deprivation, and heavy metals. These findings indicate that miRNAs may hold the key as potential targets for genetic manipulations to engineer abiotic stress tolerance in crop plants. This review is aimed to provide recent updates on plant miRNAs, their biogenesis and functions, target prediction and identification, computational tools and databases available for plant miRNAs, and their roles in abiotic stress-responses and adaptive mechanisms in major crop plants. Besides, the recent case studies for overexpressing the selected miRNAs for miRNA-mediated enhanced abiotic stress tolerance of transgenic plants have been discussed. PMID:27379117

  17. Abiotic stress QTL in lettuce crop–wild hybrids: comparing greenhouse and field experiments

    PubMed Central

    Hartman, Yorike; Hooftman, Danny A P; Uwimana, Brigitte; Schranz, M Eric; van de Wiel, Clemens C M; Smulders, Marinus J M; Visser, Richard G F; Michelmore, Richard W; van Tienderen, Peter H

    2014-01-01

    The development of stress-tolerant crops is an increasingly important goal of current crop breeding. A higher abiotic stress tolerance could increase the probability of introgression of genes from crops to wild relatives. This is particularly relevant to the discussion on the risks of new GM crops that may be engineered to increase abiotic stress resistance. We investigated abiotic stress QTL in greenhouse and field experiments in which we subjected recombinant inbred lines from a cross between cultivated Lactuca sativa cv. Salinas and its wild relative L. serriola to drought, low nutrients, salt stress, and aboveground competition. Aboveground biomass at the end of the rosette stage was used as a proxy for the performance of plants under a particular stress. We detected a mosaic of abiotic stress QTL over the entire genome with little overlap between QTL from different stresses. The two QTL clusters that were identified reflected general growth rather than specific stress responses and colocated with clusters found in earlier studies for leaf shape and flowering time. Genetic correlations across treatments were often higher among different stress treatments within the same experiment (greenhouse or field), than among the same type of stress applied in different experiments. Moreover, the effects of the field stress treatments were more correlated with those of the greenhouse competition treatments than to those of the other greenhouse stress experiments, suggesting that competition rather than abiotic stress is a major factor in the field. In conclusion, the introgression risk of stress tolerance (trans-)genes under field conditions cannot easily be predicted based on genomic background selection patterns from controlled QTL experiments in greenhouses, especially field data will be needed to assess potential (negative) ecological effects of introgression of these transgenes into wild relatives. PMID:25360276

  18. [Structural analysis for psychosocial factors including health locus of control (HLC) and sense of coherence (SOC) associated with lifestyle-related diseases].

    PubMed

    Ogawa, Y; Nakamura, H; Nagase, H; Ogino, K; Ooshita, Y; Tsukahara, S

    2001-01-01

    The purpose of this study was to clarify psychosocial characteristics associated with preventive health behavior for lifestyle-related diseases. The author performed objective health examinations and gave questionnaires to 289 men (39.7 +/- 11.8 years, mean +/- SD) and 80 women (32.8 +/- 10.4 years) engaged in office work. Psychosocial factors included lifestyle and perceived stress, as well as the health locus of control (HLC) and sense of coherence (SOC) as newly developed indicators for health behavior. The principal component analysis for men did not extract lifestyle from the psychosocial structures. Multiple regression analysis showed that internal HLC (IHLC), chance HLC (CHLC), professional HLC (PHLC) and stress significantly contributed to SOC. Principal component analysis using psychosocial factors in women showed two psychosocial structures, i.e. the second principal (high SOC, high lifestyle, and low stress) and the 4th principal components (high supernatural HLC, and high PHLC). Both components were negatively correlated with systolic blood pressure. SOC was recognized to be negatively associated with age, stress, and total cholesterol, and positively with IHLC, FHLC, lifestyle, and gamma-GTP using multiple regression analysis for women. These results indicated a distinguishable sex difference regarding the involvement of psychosocial factors including HLC and SOC in objective health. SOC seems likely to be involved not in objective health, but closely with stress, suggesting a direct influence on mental health. Lifestyle should be divided into more detailed categories such as smoking and salt intake. Structural analysis of women suggests that SOC is involved directly or indirectly through lifestyle in objective health, different from men. To further clarify causal relationships between psychosocial factors and risk factors for lifestyle-related diseases, a longitudinal study is necessary based on these results.

  19. Managing Abiotic Factors of Compost to Increase Soilborne Disease Suppression

    ERIC Educational Resources Information Center

    Griffin, Deirdre E.

    2012-01-01

    Soilborne pathogens can devastate crops, causing economic losses for farmers due to reduced yields and expensive management practices. Fumigants and fungicides have harmful impacts on the surrounding environment and can be toxic to humans. Therefore, alternative methods of disease management are important. The disease suppressive abilities of…

  20. Mutations in cardiac T-box factor gene TBX20 are associated with diverse cardiac pathologies, including defects of septation and valvulogenesis and cardiomyopathy.

    PubMed

    Kirk, Edwin P; Sunde, Margaret; Costa, Mauro W; Rankin, Scott A; Wolstein, Orit; Castro, M Leticia; Butler, Tanya L; Hyun, Changbaig; Guo, Guanglan; Otway, Robyn; Mackay, Joel P; Waddell, Leigh B; Cole, Andrew D; Hayward, Christopher; Keogh, Anne; Macdonald, Peter; Griffiths, Lyn; Fatkin, Diane; Sholler, Gary F; Zorn, Aaron M; Feneley, Michael P; Winlaw, David S; Harvey, Richard P

    2007-08-01

    The T-box family transcription factor gene TBX20 acts in a conserved regulatory network, guiding heart formation and patterning in diverse species. Mouse Tbx20 is expressed in cardiac progenitor cells, differentiating cardiomyocytes, and developing valvular tissue, and its deletion or RNA interference-mediated knockdown is catastrophic for heart development. TBX20 interacts physically, functionally, and genetically with other cardiac transcription factors, including NKX2-5, GATA4, and TBX5, mutations of which cause congenital heart disease (CHD). Here, we report nonsense (Q195X) and missense (I152M) germline mutations within the T-box DNA-binding domain of human TBX20 that were associated with a family history of CHD and a complex spectrum of developmental anomalies, including defects in septation, chamber growth, and valvulogenesis. Biophysical characterization of wild-type and mutant proteins indicated how the missense mutation disrupts the structure and function of the TBX20 T-box. Dilated cardiomyopathy was a feature of the TBX20 mutant phenotype in humans and mice, suggesting that mutations in developmental transcription factors can provide a sensitized template for adult-onset heart disease. Our findings are the first to link TBX20 mutations to human pathology. They provide insights into how mutation of different genes in an interactive regulatory circuit lead to diverse clinical phenotypes, with implications for diagnosis, genetic screening, and patient follow-up.

  1. A Model of Continental Growth and Mantle Degassing Comparing Biotic and Abiotic Worlds

    NASA Astrophysics Data System (ADS)

    Höning, D.; Hansen-Goos, H.; Spohn, T.

    2012-12-01

    While examples for interaction of the biosphere with the atmosphere can be easily cited (e.g., production and consumption of O2), interaction between the biosphere and the solid planet and its interior is much less established. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. We present an interaction model that includes mantle convection, mantle water vapor degassing at mid-oceanic ridges and regassing through subduction zones, continental crust formation and erosion and water storage and transport in a porous oceanic crust that includes hydrous mineral phases. The mantle viscosity in this model depends on the water concentration in the mantle. We use boundary layer theory of mantle convection to parameterize the mantle convection flow rate and assume that the plate speed equals the mantle flow rate. The biosphere enters the calculation through the assumption that the continental erosion rate is enhanced by a factor of several through bioactivity and through an assumed reduction of the kinetic barrier to diagenetic and metamorphic reactions (e.g., Kim et al. 2004) in the sedimentary basins in subduction zones that would lead to increased water storage capacities. We further include a stochastic model of continent-to-continent interactions that limits the effective total length of subduction zones. We use present day parameters of the Earth and explore a phase plane spanned by the percentage of surface coverage of the Earth by continents and the total water content of the mantle. We vary the ratio of the erosion rate in a postulated abiotic Earth to the present Earth, as well as the activation barrier to diagenetic and metamorphic reactions that affect the water storage capacity of the subducting crust. We find stable and unstable fixed points in

  2. The Stable Isotope Fractionation of Abiotic Reactions: A Benchmark in the Detection of Life

    NASA Technical Reports Server (NTRS)

    Summers, David P.

    2003-01-01

    mil to as low as -60 % (potentially comparable to that which accompanies the biosynthesis of organic matter). We need to understand what kind of fractionations are observed with reactions under the non-reducing or mildly reducing conditions now thought to be present on the early Earth. While nitrogen is receiving increased attention as a tool for these kinds of analyses, almost nothing is known about the isotope fractionation that one would expect for abiotic sources of fixed/reduced nitrogen. This project will measure the fixation from a series of abiotic reactions that may have been present on the early Earth (and other terrestrial planets) and produced organic material that could have ended up in the rock record. The work will look at a number of reactions, under a non- reducing, or mildly reducing, atmosphere, covering sources of prebiotic organic C & N from shock heating, to photochemistry, to hydrothermal reactions. Some reactions that we plan to study are; Shock heating of a non-reducing atmosphere to produce CO and NO (in collaboration with Chris McKay), formation of formaldehyde (and related compounds) from COY the formation of ammonia from nitrogen oxides (ultimately from NO) by ferrous iron reduction, and the hydrothermal synthesis of compounds including the hydrocarboxylation/hydrocarbonylation reaction (in collaboration with George Cody), reactions of oxalate to form hydrocarbons and other oxygenated compounds and the formation of lipids from oxalic/formic acid (in collaboration with Tom McCollom), and reactions of carbon monoxide & carbon dioxide with N2, ammonia or nitritehitrate to form hydrogen cyanide, nitriles, ammonia/amines and nitrous

  3. Circadian regulation of abiotic stress tolerance in plants

    PubMed Central

    Grundy, Jack; Stoker, Claire; Carré, Isabelle A.

    2015-01-01

    Extremes of temperatures, drought and salinity cause widespread crop losses throughout the world and impose severe limitations on the amount of land that can be used for agricultural purposes. Hence, there is an urgent need to develop crops that perform better under such abiotic stress conditions. Here, we discuss intriguing, recent evidence that circadian clock contributes to plants’ ability to tolerate different types of environmental stress, and to acclimate to them. The clock controls expression of a large fraction of abiotic stress-responsive genes, as well as biosynthesis and signaling downstream of stress response hormones. Conversely, abiotic stress results in altered expression and differential splicing of the clock genes, leading to altered oscillations of downstream stress-response pathways. We propose a range of mechanisms by which this intimate coupling between the circadian clock and environmental stress-response pathways may contribute to plant growth and survival under abiotic stress. PMID:26379680

  4. Abiotic stress responses in plant roots: a proteomics perspective

    PubMed Central

    Ghosh, Dipanjana; Xu, Jian

    2014-01-01

    Abiotic stress conditions adversely affect plant growth, resulting in significant decline in crop productivity. To mitigate and recover from the damaging effects of such adverse environmental conditions, plants have evolved various adaptive strategies at cellular and metabolic levels. Most of these strategies involve dynamic changes in protein abundance that can be best explored through proteomics. This review summarizes comparative proteomic studies conducted with roots of various plant species subjected to different abiotic stresses especially drought, salinity, flood, and cold. The main purpose of this article is to highlight and classify the protein level changes in abiotic stress response pathways specifically in plant roots. Shared as well as stressor-specific proteome signatures and adaptive mechanism(s) are simultaneously described. Such a comprehensive account will facilitate the design of genetic engineering strategies that enable the development of broad-spectrum abiotic stress-tolerant crops. PMID:24478786

  5. Influence of combined biotic and abiotic stress on nutritional quality parameters in tomato (Solanum lycopersicum).

    PubMed

    Atkinson, Nicky J; Dew, Tristan P; Orfila, Caroline; Urwin, Peter E

    2011-09-14

    Induction of abiotic stress in tomato plants has been proposed as a mechanism for improving the nutritional quality of fruits. However, the occurrence of biotic stress can interfere with normal abiotic stress responses. In this study, the combined effect of water stress and infection with plant-parasitic nematodes on the nutritional quality of tomato was investigated. Plants were exposed to one or both stresses, and the levels of phenolic compounds, carotenoids, and sugars in fruits were analyzed as well as physiological responses. Levels of carotenoids lycopene and β-carotene were lower in water-stressed tomatoes but exhibited a different response pattern under combined stress. Nematode stress was associated with increased flavonoid levels, albeit with reduced yields, while chlorogenic acid was increased by nematodes, water stress, and the combined stress. Sugar levels were higher only in tomatoes exposed to both stresses. These results emphasize the importance of studying plant stress factors in combination.

  6. Abiotic Stresses: Insight into Gene Regulation and Protein Expression in Photosynthetic Pathways of Plants.

    PubMed

    Nouri, Mohammad-Zaman; Moumeni, Ali; Komatsu, Setsuko

    2015-08-28

    Global warming and climate change intensified the occurrence and severity of abiotic stresses that seriously affect the growth and development of plants,especially, plant photosynthesis. The direct impact of abiotic stress on the activity of photosynthesis is disruption of all photosynthesis components such as photosystem I and II, electron transport, carbon fixation, ATP generating system and stomatal conductance. The photosynthetic system of plants reacts to the stress differently, according to the plant type, photosynthetic systems (C₃ or C₄), type of the stress, time and duration of the occurrence and several other factors. The plant responds to the stresses by a coordinate chloroplast and nuclear gene expression. Chloroplast, thylakoid membrane, and nucleus are the main targets of regulated proteins and metabolites associated with photosynthetic pathways. Rapid responses of plant cell metabolism and adaptation to photosynthetic machinery are key factors for survival of plants in a fluctuating environment. This review gives a comprehensive view of photosynthesis-related alterations at the gene and protein levels for plant adaptation or reaction in response to abiotic stress.

  7. Relative Importance of Biotic and Abiotic Forces on the Composition and Dynamics of a Soft-Sediment Intertidal Community.

    PubMed

    Gerwing, Travis G; Drolet, David; Hamilton, Diana J; Barbeau, Myriam A

    2016-01-01

    Top-down, bottom-up, middle-out and abiotic factors are usually viewed as main forces structuring biological communities, although assessment of their relative importance, in a single study, is rarely done. We quantified, using multivariate methods, associations between abiotic and biotic (top-down, bottom-up and middle-out) variables and infaunal population/community variation on intertidal mudflats in the Bay of Fundy, Canada, over two years. Our analysis indicated that spatial structural factors like site and plot accounted for most of the community and population variation. Although we observed a significant relationship between the community/populations and the biotic and abiotic variables, most were of minor importance relative to the structural factors. We suggest that community and population structure were relatively uncoupled from the structuring influences of biotic and abiotic factors in this system because of high concentrations of resources that sustain high densities of infauna and limit exploitative competition. Furthermore, we hypothesize that the infaunal community primarily reflects stochastic spatial events, namely a "first come, first served" process.

  8. Relative Importance of Biotic and Abiotic Forces on the Composition and Dynamics of a Soft-Sediment Intertidal Community

    PubMed Central

    Barbeau, Myriam A.

    2016-01-01

    Top-down, bottom-up, middle-out and abiotic factors are usually viewed as main forces structuring biological communities, although assessment of their relative importance, in a single study, is rarely done. We quantified, using multivariate methods, associations between abiotic and biotic (top-down, bottom-up and middle-out) variables and infaunal population/community variation on intertidal mudflats in the Bay of Fundy, Canada, over two years. Our analysis indicated that spatial structural factors like site and plot accounted for most of the community and population variation. Although we observed a significant relationship between the community/populations and the biotic and abiotic variables, most were of minor importance relative to the structural factors. We suggest that community and population structure were relatively uncoupled from the structuring influences of biotic and abiotic factors in this system because of high concentrations of resources that sustain high densities of infauna and limit exploitative competition. Furthermore, we hypothesize that the infaunal community primarily reflects stochastic spatial events, namely a “first come, first served” process. PMID:26790098

  9. Association between Cerebral Amyloid Deposition and Clinical Factors Including Cognitive Function in Geriatric Depression: Pilot Study Using Amyloid Positron Emission Tomography

    PubMed Central

    Kim, Hye-Geum; Kong, Eun-Jung; Cheon, Eun-Jin; Kim, Hae-Won; Koo, Bon-Hoon

    2016-01-01

    The purpose of this study was to explore the relationship between cerebral amyloid deposition and overall clinical factors including cognitive functions in geriatric depression by using 18F-florbetaben positron emission tomography. Thirteen subjects aged over 60 years who had a history of major depressive disorder and also had subjective memory complaint were included. Of all subjects, 3 subjects judged as amyloid positive, and the others judged as amyloid negative. Their memory, visuospatial functions and attention abilities were negatively correlated with amyloid deposition in specific brain regions, but their language and recognition abilities were not correlated with any region. The amyloid deposition of the whole brain region was significantly negatively correlated with immediate memory. PMID:27776391

  10. Monocyte-derived factors including PLA2G7 induced by macrophage-nasopharyngeal carcinoma cell interaction promote tumor cell invasiveness

    PubMed Central

    Low, Heng Boon; Png, Chin Wen; Li, Chunwei; Wang, De Yun; Wong, Soon Boon Justin; Zhang, Yongliang

    2016-01-01

    The non-keratinizing undifferentiated subtype of nasopharyngeal carcinoma (NPC) is a malignancy characterized by an intimate relationship between neoplastic cells and a non-neoplastic lymphoid component. Tumor-associated macrophages (TAMs) foster tumor progression through production of soluble mediators that support proliferation, angiogenesis, survival and invasion of malignant cells. However, the role of macrophages in the progression of NPC remains poorly understood. This study aims to investigate the functional and phenotypic changes that occur to macrophages in macrophage-NPC cell co-culture systems, and how these changes influence tumor cells. We found that monocytes, including THP-1 cells and primary human monocytes, co-cultured with C666-1 NPC cells upregulate expression of pro-inflammatory cytokines at the early stages, followed by the induction of metastasis-related genes and interferon-stimulated genes at the later stage of coculture, indicating that TAMs are “educated” by NPC cells for cancer progression. Importantly, the induction of these factors from the TAMs was also found to enhance the migratory capabilities of the NPC cells. We have also identified one of these macrophage-derived factor, phospholipase A2 Group 7 (PLA2G7), to be important in regulating tumor cell migration and a novel tumor-promoting factor in NPC. Further studies to characterize the role of PLA2G7 in tumor metastasis may help determine its potential as a therapeutic target in NPC. PMID:27487154

  11. Soluble sugars—Metabolism, sensing and abiotic stress

    PubMed Central

    Rosa, Mariana; Prado, Carolina; Podazza, Griselda; Interdonato, Roque; González, Juan A; Hilal, Mirna

    2009-01-01

    Plants are autotrophic and photosynthetic organisms that both produce and consume sugars. Soluble sugars are highly sensitive to environmental stresses, which act on the supply of carbohydrates from source organs to sink ones. Sucrose and hexoses both play dual functions in gene regulation as exemplified by the upregulation of growth-related genes and downregulation of stress-related genes. Although coordinately regulated by sugars, these growth- and stress-related genes are upregulated or downregulated through HXK-dependent and/or HXK-independent pathways. Sucrose-non-fermenting-1- (SNF1-) related protein pathway, analogue to the protein kinase (SNF-) yeast-signalling pathway, seems also involved in sugar sensing and transduction in plants. However, even if plants share with yeast some elements involved in sugar sensing, several aspects of sugar perception are likely to be peculiar to higher plants. In this paper, we have reviewed recent evidences how plants sense and respond to environmental factors through sugar-sensing mechanisms. However, we think that forward and reverse genetic analysis in combination with expression profiling must be continued to uncover many signalling components, and a full biochemical characterization of the signalling complexes will be required to determine specificity and cross-talk in abiotic stress signalling pathways. PMID:19816104

  12. Genome-wide analyses of the bZIP family reveal their involvement in the development, ripening and abiotic stress response in banana

    PubMed Central

    Hu, Wei; Wang, Lianzhe; Tie, Weiwei; Yan, Yan; Ding, Zehong; Liu, Juhua; Li, Meiying; Peng, Ming; Xu, Biyu; Jin, Zhiqiang

    2016-01-01

    The leucine zipper (bZIP) transcription factors play important roles in multiple biological processes. However, less information is available regarding the bZIP family in the important fruit crop banana. In this study, 121 bZIP transcription factor genes were identified in the banana genome. Phylogenetic analysis showed that MabZIPs were classified into 11 subfamilies. The majority of MabZIP genes in the same subfamily shared similar gene structures and conserved motifs. The comprehensive transcriptome analysis of two banana genotypes revealed the differential expression patterns of MabZIP genes in different organs, in various stages of fruit development and ripening, and in responses to abiotic stresses, including drought, cold, and salt. Interaction networks and co-expression assays showed that group A MabZIP-mediated networks participated in various stress signaling, which was strongly activated in Musa ABB Pisang Awak. This study provided new insights into the complicated transcriptional control of MabZIP genes and provided robust tissue-specific, development-dependent, and abiotic stress-responsive candidate MabZIP genes for potential applications in the genetic improvement of banana cultivars. PMID:27445085

  13. Evaluation of the predisposing factors and involved outcome of surgical treatment in bisphosphonate-related osteonecrosis of the jaw cases including bone biopsies

    PubMed Central

    2016-01-01

    Objectives This study examined the statistical relevance of whether the systemic predisposing factors affect the prognosis of surgical treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ). All cases had undergone bone biopsies to determine the characteristics of the mechanisms of BRONJ by optical microscopy. Materials and Methods The data included 54 BRONJ cases who underwent surgery and in whom bone biopsies were performed. The results of surgery were evaluated and the results were classified into 3 categories: normal recovery, delayed recovery, and recurrence after surgery. The medical history, such as diabetes mellitus, medication of steroids, malignancies on other sites was investigated for an evaluation of the systemic predisposing factors in relation to the prognosis. The three factors involved with the medication of bisphosphonate (BP) were the medication route, medication period, and drug holiday of BP before surgery. The serum C-terminal cross-linking telopeptide (CTX) value and presence of microorganism colony in bone biopsy specimens were also checked. Statistical analysis was then carried out to determine the relationship between these factors and the results of surgery. Results The group of patients suffering from diabetes and on steroids tended to show poorer results after surgery. Parenteral medication of BP made the patients have a poorer prognosis after surgery than oral medication. In contrast, the medication period and drug holiday of BP before surgery did not have significance with the results of surgery nor did the serum CTX value and presence of microorganism colony. Necrotic bone specimens in this study typically showed disappearing new bone formation around the osteocytic lacunae and destroyed Howship's lacunae. Conclusion Although many variables exist, this study could in part, predict the prognosis of surgical treatment of BRONJ by taking the patient's medical history. PMID:27595086

  14. Abiotic Stress Responses and Microbe-Mediated Mitigation in Plants: The Omics Strategies

    PubMed Central

    Meena, Kamlesh K.; Sorty, Ajay M.; Bitla, Utkarsh M.; Choudhary, Khushboo; Gupta, Priyanka; Pareek, Ashwani; Singh, Dhananjaya P.; Prabha, Ratna; Sahu, Pramod K.; Gupta, Vijai K.; Singh, Harikesh B.; Krishanani, Kishor K.; Minhas, Paramjit S.

    2017-01-01

    Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defense under adverse external conditions. Plant-microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant-microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding

  15. Abiotic reduction reactions of anthropogenic organic chemicals in anaerobic systems: A critical review

    NASA Astrophysics Data System (ADS)

    Macalady, Donald L.; Tratnyek, Paul G.; Grundl, Timothy J.

    1986-02-01

    This review is predicated upon the need for a detailed process-level understanding of factors influencing the reduction of anthropogenic organic chemicals in natural aquatic systems. In particular, abiotic reductions of anthropogenic organic chemicals are reviewed. The most important reductive reaction is alkyl dehalogenation (replacement of chloride with hydrogen) which occurs in organisms, sediments, sewage sludge, and reduced iron porphyrin model systems. An abiotic mechanism involving a free radical intermediate has been proposed. The abstraction of vicinal dihalides (also termed dehalogenation) is another reduction that may have an abiotic component in natural systems. Reductive dehalogenation of aryl halides has recently been reported and further study of this reaction is needed. Several other degradation reactions of organohalides that occur in anaerobic environments are mentioned, the most important of which is dehydrohalogenation. The reduction of nitro groups to amines has also been thoroughly studied. The reactions can occur abiotically, and are affected by the redox conditions of the experimental system. However, a relationship between nitro-reduction rate and measured redox potential has not been clearly established. Reductive dealkylation of the N- and O-heteroatom of hydrocarbon pollutants has been observed but not investigated in detail. Azo compounds can be reduced to their hydrazo derivatives and a thorough study of this reaction indicates that it can be caused by extracellular electron transfer agents. Quinone-hydroquinone couples are important reactive groups in humic materials and similar structures in resazurin and indigo carmine make them useful as models for environmental redox conditions. The interconversion of sulfones, sulfoxides, and sulfides is a redox process and is implicated in the degradation of several pesticides though the reactions need more study. Two reductive heterocyclic cleavage reactions are also mentioned. Finally, several

  16. Abiotic Stress Responses and Microbe-Mediated Mitigation in Plants: The Omics Strategies.

    PubMed

    Meena, Kamlesh K; Sorty, Ajay M; Bitla, Utkarsh M; Choudhary, Khushboo; Gupta, Priyanka; Pareek, Ashwani; Singh, Dhananjaya P; Prabha, Ratna; Sahu, Pramod K; Gupta, Vijai K; Singh, Harikesh B; Krishanani, Kishor K; Minhas, Paramjit S

    2017-01-01

    Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defense under adverse external conditions. Plant-microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant-microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding

  17. Proline accumulation is a general response to abiotic stress in the date palm tree (Phoenix dactylifera L.).

    PubMed

    Yaish, M W

    2015-08-19

    Plants exposed to certain abiotic stress conditions tend to produce the amino acid proline, which acts as an active osmolyte, a metal chelator, an antioxidant, and a signaling molecule. There is increasing evidence that proline accumulates in plants due to a wide range of abiotic stress, in particular high soil salinity and drought. Therefore, proline content is often used as a marker-assisted breeding tool aimed at improving drought and salinity tolerance. In this study, it was investigated whether proline accumulation in date palm (Phoenix dactylifera L.) seedlings occurs solely due to high salinity and drought stresses or due to other unspecified abiotic stresses, including salinity and salinity shock, drought, extreme temperatures, and abscisic acid. The free proline assays revealed that this amino acid over-accumulated in the roots and leaves of each stress-treated plant, and was remarkably high when leaves were exposed to suboptimum temperatures and salinity stress. These results indicate that the production of proline is a common response to various abiotic stresses and its differential accumulation cannot be used as a molecular marker in date palm breeding programs aimed at improving drought or salinity tolerance traits in date palms. This conclusion is consistent with the theory that the molecular outcomes of abiotic stresses are often non-specific.

  18. Nature and Reactivity of Sediment-Associated Spiked Fe(II) Toward Abiotic Uranium Reduction

    NASA Astrophysics Data System (ADS)

    Kukkadapu, R.; Fox, P. M.; Davis, J.

    2011-12-01

    Uranium (U) is a priority contaminant at U.S. Department of Energy Uranium Mill Tailings Remedial Action (UMTRA) sites. Mobility of U in contaminated aquifers is governed by a complex assortment of site-specific biogeochemical and hydrological properties, sediment Fe-mineralogy, and redox status. There is a particular interest in understanding factors governing U attenuation to Fe-mineralogy under natural conditions. Thus, the goal of this work is to investigate geochemical effects of Fe redox state on U mobility under conditions relevant to the Rifle aquifer, an UMTRA site. Particularly, the focus is to gain insights into the degree and mechanism of Fe(II) uptake by Rifle sediments that exhibit complex Fe-mineralogy composed of various Fe-oxides and Fe-containing clays and on the possibility of abiotic U(VI) reduction by adsorbed Fe(II) and secondary Fe(II) minerals. Earlier field studies where Fe(II)-amended groundwater was injected into the Rifle aquifer indicated: a) Fe(II) uptake by Rifle sediments is extensive and b) abiotic U(VI) reduction by Fe(II) may be important at pH 8.3. Batch reactions between Rifle sediment and 57Fe(II) (57Fe isotope is a Mossbauer sensitive nuclide with a natural abundance of 2%) under conditions relevant to the Rifle aquifer indicated that, depending on the solution conditions: a) a large fraction of the spiked 57Fe(II) (55-100%) is oxidized to 57Fe(III) on sediment surfaces and, at pH 7.2, the degree of oxidation decreased as Fe(II) loading increased; b) the 57Fe(II)-oxidation is coupled to the transformation of an intrinsic ferrihydrite-like mineral to a nanoparticulate, Fe(II)/57Fe(III)-like mineral phase, and c) increasing pH from 7.2 to 8.3 and including carbonate in the medium has little or no effect on percent oxidation or mineral transformation. Preliminary X-ray absorption near edge structure (XANES) spectroscopy studies suggested that 20-30% of abiotic U(VI) reduction occurred, both at pH 7.2 and 8.3, in the sediments

  19. Coordinating Metabolite Changes with Our Perception of Plant Abiotic Stress Responses: Emerging Views Revealed by Integrative—Omic Analyses

    PubMed Central

    Radomiljac, Jordan D.; Whelan, James; van der Merwe, Margaretha

    2013-01-01

    Metabolic configuration and adaptation under a range of abiotic stresses, including drought, heat, salinity, cold, and nutrient deprivation, are subjected to an intricate span of molecular pathways that work in parallel in order to enhance plant fitness and increase stress tolerance. In recent years, unprecedented advances have been made in identifying and linking different abiotic stresses, and the current challenge in plant molecular biology is deciphering how the signaling responses are integrated and transduced throughout metabolism. Metabolomics have often played a fundamental role in elucidating the distinct and overlapping biochemical changes that occur in plants. However, a far greater understanding and appreciation of the complexity in plant metabolism under specific stress conditions have become apparent when combining metabolomics with other—omic platforms. This review focuses on recent advances made in understanding the global changes occurring in plant metabolism under abiotic stress conditions using metabolite profiling as an integrated discovery platform. PMID:24958149

  20. The tomato DWD motif-containing protein DDI1 interacts with the CUL4–DDB1-based ubiquitin ligase and plays a pivotal role in abiotic stress responses

    SciTech Connect

    Miao, Min; Zhu, Yunye; Qiao, Maiju; Tang, Xiaofeng; Zhao, Wei; Xiao, Fangming; Liu, Yongsheng

    2014-08-08

    Highlights: • We identify DDI1 as a DAMAGED DNA BINDING PROTEIN1 (DDB1)-interacting protein. • DDI1 interacts with the CUL4–DDB1-based ubiquitin ligase in the nucleus. • DDI1 plays a positive role in regulating abiotic stress response in tomato. - Abstract: CULLIN4(CUL4)–DAMAGED DNA BINDING PROTEIN1 (DDB1)-based ubiquitin ligase plays significant roles in multiple physiological processes via ubiquitination-mediated degradation of relevant target proteins. The DDB1–CUL4-associated factor (DCAF) acts as substrate receptor in the CUL4–DDB1 ubiquitin ligase complex and determines substrate specificity. In this study, we identified a tomato (Solanum lycopersicum) DDB1-interacting (DDI1) protein as a DCAF protein involved in response to abiotic stresses, including UV radiation, high salinity and osmotic stress. Co-immunoprecipitation and bimolecular fluorescence complementation assay indicated that DDI1 associates with CUL4–DDB1 in the nucleus. Quantitative RT-PCR analysis indicated the DDI1 gene is induced by salt, mannitol and UV-C treatment. Moreover, transgenic tomato plants with overexpression or knockdown of the DDI1 gene exhibited enhanced or attenuated tolerance to salt/mannitol/UV-C, respectively. Thus, our data suggest that DDI1 functions as a substrate receptor of the CUL4–DDB1 ubiquitin ligase, positively regulating abiotic stress response in tomato.

  1. Polyamines and abiotic stress in plants: a complex relationship1

    PubMed Central

    Minocha, Rakesh; Majumdar, Rajtilak; Minocha, Subhash C.

    2014-01-01

    The physiological relationship between abiotic stress in plants and polyamines was reported more than 40 years ago. Ever since there has been a debate as to whether increased polyamines protect plants against abiotic stress (e.g., due to their ability to deal with oxidative radicals) or cause damage to them (perhaps due to hydrogen peroxide produced by their catabolism). The observation that cellular polyamines are typically elevated in plants under both short-term as well as long-term abiotic stress conditions is consistent with the possibility of their dual effects, i.e., being protectors from as well as perpetrators of stress damage to the cells. The observed increase in tolerance of plants to abiotic stress when their cellular contents are elevated by either exogenous treatment with polyamines or through genetic engineering with genes encoding polyamine biosynthetic enzymes is indicative of a protective role for them. However, through their catabolic production of hydrogen peroxide and acrolein, both strong oxidizers, they can potentially be the cause of cellular harm during stress. In fact, somewhat enigmatic but strong positive relationship between abiotic stress and foliar polyamines has been proposed as a potential biochemical marker of persistent environmental stress in forest trees in which phenotypic symptoms of stress are not yet visible. Such markers may help forewarn forest managers to undertake amelioration strategies before the appearance of visual symptoms of stress and damage at which stage it is often too late for implementing strategies for stress remediation and reversal of damage. This review provides a comprehensive and critical evaluation of the published literature on interactions between abiotic stress and polyamines in plants, and examines the experimental strategies used to understand the functional significance of this relationship with the aim of improving plant productivity, especially under conditions of abiotic stress. PMID:24847338

  2. Coupled biotic-abiotic oxidation of organic matter by biogenic MnO_{2}

    NASA Astrophysics Data System (ADS)

    Gonzalez, Julia; Peña, Jasquelin

    2016-04-01

    Some reactive soil minerals are strongly implicated in stabilising organic matter. However, others can play an active role in the oxidation of organic molecules. In natural systems, layer-type manganese oxide minerals (MnO2) typically occur as biomineral assemblages consisting of mineral particles and microbial biomass. Both the mineral and biological fractions of the assemblage can be powerful oxidants of organic C. The biological compartment relies on a set of enzymes to drive oxidative transformations of reduced C-substrates, whereas MnO2 minerals are strong, less specific abiotic oxidants that are assumed to rely on interfacial interactions between C-substrates and the mineral surface. This project aims to understand the coupling between microbial C mineralization and abiotic C oxidation mediated by MnO2 in bacterial-MnO2 assemblages. Specifically, under conditions of high C turnover, microbial respiration can significantly alter local pH, dissolved oxygen and pool of available reductants, which may modify rates and mechanism of C oxidation by biotic and abiotic components. We first investigated changes in the solution chemistry of Pseudomonas putida suspensions exposed to varying concentrations of glucose, chosen to represent readily bioavailable substrates in soils. Glucose concentrations tested ranged between 0 and 5.5mM and changes in pH, dissolved oxygen and dissolved organic and inorganic carbon were tracked over 48h. We then combined literature review and wet-chemical experiments to compile the pH dependence of rates of organic substrate oxidation by MnO2, including glucose. Our results demonstrate a strong pH dependence for these abiotic reactions. In assemblages of P. putida - MnO2, kinetic limitations for abiotic C oxidation by MnO2 are overcome by changes in biogeochemical conditions that result from bacterial C metabolism. When extrapolated to a soil solution confronted to an input of fresh dissolved organic matter, bacterial C metabolism of the

  3. Wheat proteomics: proteome modulation and abiotic stress acclimation

    PubMed Central

    Komatsu, Setsuko; Kamal, Abu H. M.; Hossain, Zahed

    2014-01-01

    Cellular mechanisms of stress sensing and signaling represent the initial plant responses to adverse conditions. The development of high-throughput “Omics” techniques has initiated a new era of the study of plant molecular strategies for adapting to environmental changes. However, the elucidation of stress adaptation mechanisms in plants requires the accurate isolation and characterization of stress-responsive proteins. Because the functional part of the genome, namely the proteins and their post-translational modifications, are critical for plant stress responses, proteomic studies provide comprehensive information about the fine-tuning of cellular pathways that primarily involved in stress mitigation. This review summarizes the major proteomic findings related to alterations in the wheat proteomic profile in response to abiotic stresses. Moreover, the strengths and weaknesses of different sample preparation techniques, including subcellular protein extraction protocols, are discussed in detail. The continued development of proteomic approaches in combination with rapidly evolving bioinformatics tools and interactive databases will facilitate understanding of the plant mechanisms underlying stress tolerance. PMID:25538718

  4. Comparative study of biogenic and abiotic iron-containing materials

    NASA Astrophysics Data System (ADS)

    Cherkezova-Zheleva, Z.; Shopska, M.; Paneva, D.; Kovacheva, D.; Kadinov, G.; Mitov, I.

    2016-12-01

    Series of iron-based biogenic materials prepared by cultivation of Leptothrix group of bacteria in different feeding media ( Sphaerotilus-Leptothrix group of bacteria isolation medium, Adler, Lieske and silicon-iron-glucose-peptone) were studied. Control samples were obtained in the same conditions and procedures but the nutrition media were not infected with bacteria, i.e. they were sterile. Room and low temperature Mössbauer spectroscopy, powder X-ray diffraction (XRD), and infrared spectroscopy (IRS) were used to reveal the composition and physicochemical properties of biomass and respective control samples. Comparative analysis showed differences in their composition and dispersity of present phases. Sample composition included different ratio of nanodimensional iron oxyhydroxide and oxide phases. Relaxation phenomena such as superparamagnetism or collective magnetic excitation behaviour were registered for some of them. The experimental data showed that the biogenic materials were enriched in oxyhydroxides of high dispersion. Catalytic behaviour of a selected biomass and abiotic material were studied in the reaction of CO oxidation. In situ diffuse-reflectance (DR) IRS was used to monitor the phase transformations in the biomass and CO conversion.

  5. Distribution of vascular epiphytes along a tropical elevational gradient: disentangling abiotic and biotic determinants

    PubMed Central

    Ding, Yi; Liu, Guangfu; Zang, Runguo; Zhang, Jian; Lu, Xinghui; Huang, Jihong

    2016-01-01

    Epiphytic vascular plants are common species in humid tropical forests. Epiphytes are influenced by abiotic and biotic variables, but little is known about the relative importance of direct and indirect effects on epiphyte distribution. We surveyed 70 transects (10 m × 50 m) along an elevation gradient (180 m–1521 m) and sampled all vascular epiphytes and trees in a typical tropical forest on Hainan Island, south China. The direct and indirect effects of abiotic factors (climatic and edaphic) and tree community characteristics on epiphytes species diversity were examined. The abundance and richness of vascular epiphytes generally showed a unimodal curve with elevation and reached maximum value at ca. 1300 m. The species composition in transects from high elevation (above 1200 m) showed a more similar assemblage. Climate explained the most variation in epiphytes species diversity followed by tree community characteristics and soil features. Overall, climate (relative humidity) and tree community characteristics (tree size represented by basal area) had the strongest direct effects on epiphyte diversity while soil variables (soil water content and available phosphorus) mainly had indirect effects. Our study suggests that air humidity is the most important abiotic while stand basal area is the most important biotic determinants of epiphyte diversity along the tropical elevational gradient. PMID:26796667

  6. MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

    SciTech Connect

    Beyenal, Haluk; McLEan, Jeff; Majors, Paul; Fredrickson, Jim

    2013-11-14

    The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.

  7. Distribution of vascular epiphytes along a tropical elevational gradient: disentangling abiotic and biotic determinants.

    PubMed

    Ding, Yi; Liu, Guangfu; Zang, Runguo; Zhang, Jian; Lu, Xinghui; Huang, Jihong

    2016-01-22

    Epiphytic vascular plants are common species in humid tropical forests. Epiphytes are influenced by abiotic and biotic variables, but little is known about the relative importance of direct and indirect effects on epiphyte distribution. We surveyed 70 transects (10 m × 50 m) along an elevation gradient (180 m-1521 m) and sampled all vascular epiphytes and trees in a typical tropical forest on Hainan Island, south China. The direct and indirect effects of abiotic factors (climatic and edaphic) and tree community characteristics on epiphytes species diversity were examined. The abundance and richness of vascular epiphytes generally showed a unimodal curve with elevation and reached maximum value at ca. 1300 m. The species composition in transects from high elevation (above 1200 m) showed a more similar assemblage. Climate explained the most variation in epiphytes species diversity followed by tree community characteristics and soil features. Overall, climate (relative humidity) and tree community characteristics (tree size represented by basal area) had the strongest direct effects on epiphyte diversity while soil variables (soil water content and available phosphorus) mainly had indirect effects. Our study suggests that air humidity is the most important abiotic while stand basal area is the most important biotic determinants of epiphyte diversity along the tropical elevational gradient.

  8. Natural variation in abiotic stress responsive gene expression and local adaptation to climate in Arabidopsis thaliana.

    PubMed

    Lasky, Jesse R; Des Marais, David L; Lowry, David B; Povolotskaya, Inna; McKay, John K; Richards, James H; Keitt, Timothy H; Juenger, Thomas E

    2014-09-01

    Gene expression varies widely in natural populations, yet the proximate and ultimate causes of this variation are poorly known. Understanding how variation in gene expression affects abiotic stress tolerance, fitness, and adaptation is central to the field of evolutionary genetics. We tested the hypothesis that genes with natural genetic variation in their expression responses to abiotic stress are likely to be involved in local adaptation to climate in Arabidopsis thaliana. Specifically, we compared genes with consistent expression responses to environmental stress (expression stress responsive, "eSR") to genes with genetically variable responses to abiotic stress (expression genotype-by-environment interaction, "eGEI"). We found that on average genes that exhibited eGEI in response to drought or cold had greater polymorphism in promoter regions and stronger associations with climate than those of eSR genes or genomic controls. We also found that transcription factor binding sites known to respond to environmental stressors, especially abscisic acid responsive elements, showed significantly higher polymorphism in drought eGEI genes in comparison to eSR genes. By contrast, eSR genes tended to exhibit relatively greater pairwise haplotype sharing, lower promoter diversity, and fewer nonsynonymous polymorphisms, suggesting purifying selection or selective sweeps. Our results indicate that cis-regulatory evolution and genetic variation in stress responsive gene expression may be important mechanisms of local adaptation to climatic selective gradients.

  9. MicroRNAs play critical roles during plant development and in response to abiotic stresses

    PubMed Central

    de Lima, Júlio César; Loss-Morais, Guilherme; Margis, Rogerio

    2012-01-01

    MicroRNAs (miRNAs) have been identified as key molecules in regulatory networks. The fine-tuning role of miRNAs in addition to the regulatory role of transcription factors has shown that molecular events during development are tightly regulated. In addition, several miRNAs play crucial roles in the response to abiotic stress induced by drought, salinity, low temperatures, and metals such as aluminium. Interestingly, several miRNAs have overlapping roles with regard to development, stress responses, and nutrient homeostasis. Moreover, in response to the same abiotic stresses, different expression patterns for some conserved miRNA families among different plant species revealed different metabolic adjustments. The use of deep sequencing technologies for the characterisation of miRNA frequency and the identification of new miRNAs adds complexity to regulatory networks in plants. In this review, we consider the regulatory role of miRNAs in plant development and abiotic stresses, as well as the impact of deep sequencing technologies on the generation of miRNA data. PMID:23412556

  10. MicroRNAs play critical roles during plant development and in response to abiotic stresses.

    PubMed

    de Lima, Júlio César; Loss-Morais, Guilherme; Margis, Rogerio

    2012-12-01

    MicroRNAs (miRNAs) have been identified as key molecules in regulatory networks. The fine-tuning role of miRNAs in addition to the regulatory role of transcription factors has shown that molecular events during development are tightly regulated. In addition, several miRNAs play crucial roles in the response to abiotic stress induced by drought, salinity, low temperatures, and metals such as aluminium. Interestingly, several miRNAs have overlapping roles with regard to development, stress responses, and nutrient homeostasis. Moreover, in response to the same abiotic stresses, different expression patterns for some conserved miRNA families among different plant species revealed different metabolic adjustments. The use of deep sequencing technologies for the characterisation of miRNA frequency and the identification of new miRNAs adds complexity to regulatory networks in plants. In this review, we consider the regulatory role of miRNAs in plant development and abiotic stresses, as well as the impact of deep sequencing technologies on the generation of miRNA data.

  11. Semiochemicals from ex situ abiotically stressed cactus tissue: a contributing role of fungal spores?

    PubMed

    Beck, John J; Baig, Nausheena; Cook, Daniel; Mahoney, Noreen E; Marsico, Travis D

    2014-12-24

    Semiochemicals play a central role in communication between plants and insects, such as signaling the location of a suitable host. Fungi on host plants can also play an influential role in communicating certain plant vulnerabilities to an insect. The spiroketal conophthorin is an important semiochemical produced by developing fungal spores. Spiroketals are also used as signals for scolytid communication. Plants and fungi are known to emit varying volatile profiles under biotic and abiotic stress. This paper reports distinctive temporal-volatile profiles from three abiotic treatments, room temperature (control), -15 °C (cold), and -15 °C to room temperature (shock), of cactus tissue plugs. Volatiles from the three treatments included monoterpenes from control plugs, compounds of varying classes and origin at later stages for cold plugs, and known semiochemicals, including spiroketals, at later stages for shock plugs. The results highlight several important findings: a unique tissue source of the spiroketals; abiotic cold-shock stress is indicated as the cause of spiroketal production; and, given previous findings of spirogenesis, fungal spore involvement is a probable biosynthetic origin of the spiroketals. These findings suggest an important role of fungal volatiles as signaling plant vulnerability to insects.

  12. Roots Withstanding their Environment: Exploiting Root System Architecture Responses to Abiotic Stress to Improve Crop Tolerance

    PubMed Central

    Koevoets, Iko T.; Venema, Jan Henk; Elzenga, J. Theo. M.; Testerink, Christa

    2016-01-01

    To face future challenges in crop production dictated by global climate changes, breeders and plant researchers collaborate to develop productive crops that are able to withstand a wide range of biotic and abiotic stresses. However, crop selection is often focused on shoot performance alone, as observation of root properties is more complex and asks for artificial and extensive phenotyping platforms. In addition, most root research focuses on development, while a direct link to the functionality of plasticity in root development for tolerance is often lacking. In this paper we review the currently known root system architecture (RSA) responses in Arabidopsis and a number of crop species to a range of abiotic stresses, including nutrient limitation, drought, salinity, flooding, and extreme temperatures. For each of these stresses, the key molecular and cellular mechanisms underlying the RSA response are highlighted. To explore the relevance for crop selection, we especially review and discuss studies linking root architectural responses to stress tolerance. This will provide a first step toward understanding the relevance of adaptive root development for a plant’s response to its environment. We suggest that functional evidence on the role of root plasticity will support breeders in their efforts to include root properties in their current selection pipeline for abiotic stress tolerance, aimed to improve the robustness of crops. PMID:27630659

  13. BnNAC485 is involved in abiotic stress responses and flowering time in Brassica napus.

    PubMed

    Ying, Lu; Chen, Haiying; Cai, Weiming

    2014-06-01

    NAC domain proteins are plant-specific transcription factors that play important roles in plant growth and development. In this present study, we isolated BnNAC485 from Brassica napus L. (cv. HuYou15) and found that it showed high homology (84% at the amino acid level) with a NAC protein called AtRD26/ANAC072. BnNAC485 was specifically expressed in cotyledons and leaves of young seedlings, and expression was induced by abiotic stress and abscisic acid (ABA) treatment. The BnNAC485 protein localized to the nucleus. Over-expression of BnNAC485 enhanced tolerance to abiotic stress compared with wild-type plants in both B. napus and Arabidopsis thaliana. Furthermore, under exogenous ABA stress, BnNAC485 over-expression lines showed hypersensitivity to this treatment compared with wild-type B. napus and A. thaliana plants. Moreover, exogenous ABA treatment enhanced stomatal closing in B. napus plants over-expressing BnNAC485. Real-time RT-PCR assays showed that some abiotic- or ABA-responsive genes were up-regulated in A. thaliana plants over-expressing BnNAC485. Additionally, the transgenic lines flowered earlier than the wild-type B. napus and A. thaliana plants and the expression patterns of certain circadian clock genes were found to have changed. These results suggest that BnNAC485 acts in response to abiotic stress in plants via an ABA-mediated pathway and this gene can also alter plant flowering time.

  14. Abiotic stress responses in plants: roles of calmodulin-regulated proteins

    PubMed Central

    Virdi, Amardeep S.; Singh, Supreet; Singh, Prabhjeet

    2015-01-01

    Intracellular changes in calcium ions (Ca2+) in response to different biotic and abiotic stimuli are detected by various sensor proteins in the plant cell. Calmodulin (CaM) is one of the most extensively studied Ca2+-sensing proteins and has been shown to be involved in transduction of Ca2+ signals. After interacting with Ca2+, CaM undergoes conformational change and influences the activities of a diverse range of CaM-binding proteins. A number of CaM-binding proteins have also been implicated in stress responses in plants, highlighting the central role played by CaM in adaptation to adverse environmental conditions. Stress adaptation in plants is a highly complex and multigenic response. Identification and characterization of CaM-modulated proteins in relation to different abiotic stresses could, therefore, prove to be essential for a deeper understanding of the molecular mechanisms involved in abiotic stress tolerance in plants. Various studies have revealed involvement of CaM in regulation of metal ions uptake, generation of reactive oxygen species and modulation of transcription factors such as CAMTA3, GTL1, and WRKY39. Activities of several kinases and phosphatases have also been shown to be modulated by CaM, thus providing further versatility to stress-associated signal transduction pathways. The results obtained from contemporary studies are consistent with the proposed role of CaM as an integrator of different stress signaling pathways, which allows plants to maintain homeostasis between different cellular processes. In this review, we have attempted to present the current state of understanding of the role of CaM in modulating different stress-regulated proteins and its implications in augmenting abiotic stress tolerance in plants. PMID:26528296

  15. Plant cell organelle proteomics in response to abiotic stress.

    PubMed

    Hossain, Zahed; Nouri, Mohammad-Zaman; Komatsu, Setsuko

    2012-01-01

    Proteomics is one of the finest molecular techniques extensively being used for the study of protein profiling of a given plant species experiencing stressed conditions. Plants respond to a stress by alteration in the pattern of protein expression, either by up-regulating of the existing protein pool or by the synthesizing novel proteins primarily associated with plants antioxidative defense mechanism. Improved protein extraction protocols and advance techniques for identification of novel proteins have been standardized in different plant species at both cellular and whole plant level for better understanding of abiotic stress sensing and intracellular stress signal transduction mechanisms. In contrast, an in-depth proteome study of subcellular organelles could generate much detail information about the intrinsic mechanism of stress response as it correlates the possible relationship between the protein abundance and plant stress tolerance. Although a wealth of reviews devoted to plant proteomics are available, review articles dedicated to plant cell organelle proteins response under abiotic stress are very scanty. In the present review, an attempt has been made to summarize all significant contributions related to abiotic stresses and their impacts on organelle proteomes for better understanding of plants abiotic stress tolerance mechanism at protein level. This review will not only provide new insights into the plants stress response mechanisms, which are necessary for future development of genetically engineered stress tolerant crop plants for the benefit of humankind, but will also highlight the importance of studying changes in protein abundance within the cell organelles in response to abiotic stress.

  16. The use of biotic and abiotic components of Red Sea coastal areas as indicators of ecosystem health.

    PubMed

    Omar, Wael A; Saleh, Yousef S; Marie, Mohamed-Assem S

    2016-03-01

    A biomonitoring study was conducted using some biotic (Pomadasys hasta and Lutjanus russellii fish) and abiotic (water and sediment) components of the Red Sea coast of Hodeida, Yemen Republic along two polluted sites (Al-Dawar beach and Urj village) in comparison to a reference site (Al-Nukhailah beach). The studied fish biomarkers included hepatosomatic index (HSI), condition factor (K), scaled mass index (SMI), catalase, glutathione-S-transferase (GST), malondialdehyde (MDA), total protein and albumin. In addition, metals (Fe, Cu, Zn, Pb and Cd) concentrations in water and sediment were measured and sediment pollution assessment was carried out using contamination factor (CF), geoaccumulation index (Igeo), pollution load index (PLI) and enrichment factor (EF). The studied metals concentration in water and sediment samples showed significant increase among the polluted sites in comparison to the reference site. Sediment pollution assessment generally confirmed that Urj village was the most contaminated site followed by Al-Dawar beach. Catalase, GST and MDA proved to be the most responsive biomarkers with increased values of GST and MDA at sites influenced by agricultural, urban and industrial activities while catalase, HSI, K, SMI, total protein and albumin showed the opposite trend. This study recommends monitoring of sediment Igeo and EF values as well as SMI, catalase, GST and MDA as sensitive indicators of different anthropogenic activities and their effects on aquatic ecosystems under complex and different gradients of metal pollution. In addition, P. hasta proved to be more sensitive towards the detected pollution condition.

  17. Phytoplankton dynamics of a subtropical reservoir controlled by the complex interplay among hydrological, abiotic, and biotic variables.

    PubMed

    Kuo, Yi-Ming; Wu, Jiunn-Tzong

    2016-12-01

    This study was conducted to identify the key factors related to the spatiotemporal variations in phytoplankton abundance in a subtropical reservoir from 2006 to 2010 and to assist in developing strategies for water quality management. Dynamic factor analysis (DFA), a dimension-reduction technique, was used to identify interactions between explanatory variables (i.e., environmental variables) and abundance (biovolume) of predominant phytoplankton classes. The optimal DFA model significantly described the dynamic changes in abundances of predominant phytoplankton groups (including dinoflagellates, diatoms, and green algae) at five monitoring sites. Water temperature, electrical conductivity, water level, nutrients (total phosphorus, NO3-N, and NH3-N), macro-zooplankton, and zooplankton were the key factors affecting the dynamics of aforementioned phytoplankton. Therefore, transformations of nutrients and reactions between water quality variables and aforementioned processes altered by hydrological conditions may also control the abundance dynamics of phytoplankton, which may represent common trends in the DFA model. The meandering shape of Shihmen Reservoir and its surrounding rivers caused a complex interplay between hydrological conditions and abiotic and biotic variables, resulting in phytoplankton abundance that could not be estimated using certain variables. Additional water quality and hydrological variables at surrounding rivers and monitoring plans should be executed a few days before and after reservoir operations and heavy storm, which would assist in developing site-specific preventive strategies to control phytoplankton abundance.

  18. Plasma ω-3 fatty acid levels negatively and ω-6 fatty acid levels positively associated with other cardiovascular risk factors including homocysteine in severe obese subjects.

    PubMed

    Mehmetoglu, Idris; Yerlikaya, F Hümeyra; Kurban, Sevil; Polat, Hakkı

    2012-01-01

    Obesity and homocysteine (tHcy) are important risk factors for cardiovascular diseases (CVD). Plasma omega-3 fatty acids (ω-3 FAs) and omega-6 fatty acids (ω-6 FAs) are essential fatty acids with diverse biological effects in human health and disease. We have investigated the relation of plasma ω-3 FAs and ω-6 FAs levels with other cardiovascular risk factors including tHcy in severe obese subjects. This study was performed on 96 severe obese and 65 normal weight subjects. Plasma fatty acid composition was measured by GC/MS and serum tHcy level was measured by HPLC methods. There were no differences between groups in terms of concentrations of serum tHcy, plasma ω-3 FAs, ω-6 FAs and ω-3/ω-6 ratio, whereas serum vitamin B-12 (p<0.01) and folic acid (p<0.05) levels were lower than those of the normal weight subjects. Homocysteine positively correlated with ω-6 FAs and negatively correlated with ω-3 FAs in severe obese and normal weight subjects. Serum vitamin B-12 positively correlated with ω-3 FAs (p<0.01) and ω-3/ω-6 ratio (p<0.01) and negatively correlated with ω-6 FAs (p<0.05) in severe obese subjects. Serum folic acid positively correlated with ω-3 FAs (p<0.01) in severe obese subjects. Our results suggest an association between the plasma ω-3 FAs and ω-6 FAs and serum tHcy concentrations in severe obese and normal weight subjects. Low levels vitamin B-12 and folic acid may have been responsible for the elevated tHcy levels in severe obese subjects, increasing the risk for future development of cardiovascular diseases.

  19. The TAL effector PthA4 interacts with nuclear factors involved in RNA-dependent processes including a HMG protein that selectively binds poly(U) RNA.

    PubMed

    de Souza, Tiago Antonio; Soprano, Adriana Santos; de Lira, Nayara Patricia Vieira; Quaresma, Alexandre José Christino; Pauletti, Bianca Alves; Paes Leme, Adriana Franco; Benedetti, Celso Eduardo

    2012-01-01

    Plant pathogenic bacteria utilize an array of effector proteins to cause disease. Among them, transcriptional activator-like (TAL) effectors are unusual in the sense that they modulate transcription in the host. Although target genes and DNA specificity of TAL effectors have been elucidated, how TAL proteins control host transcription is poorly understood. Previously, we showed that the Xanthomonas citri TAL effectors, PthAs 2 and 3, preferentially targeted a citrus protein complex associated with transcription control and DNA repair. To extend our knowledge on the mode of action of PthAs, we have identified new protein targets of the PthA4 variant, required to elicit canker on citrus. Here we show that all the PthA4-interacting proteins are DNA and/or RNA-binding factors implicated in chromatin remodeling and repair, gene regulation and mRNA stabilization/modification. The majority of these proteins, including a structural maintenance of chromosomes protein (CsSMC), a translin-associated factor X (CsTRAX), a VirE2-interacting protein (CsVIP2), a high mobility group (CsHMG) and two poly(A)-binding proteins (CsPABP1 and 2), interacted with each other, suggesting that they assemble into a multiprotein complex. CsHMG was shown to bind DNA and to interact with the invariable leucine-rich repeat region of PthAs. Surprisingly, both CsHMG and PthA4 interacted with PABP1 and 2 and showed selective binding to poly(U) RNA, a property that is novel among HMGs and TAL effectors. Given that homologs of CsHMG, CsPABP1, CsPABP2, CsSMC and CsTRAX in other organisms assemble into protein complexes to regulate mRNA stability and translation, we suggest a novel role of TAL effectors in mRNA processing and translational control.

  20. The SEB-1 Transcription Factor Binds to the STRE Motif in Neurospora crassa and Regulates a Variety of Cellular Processes Including the Stress Response and Reserve Carbohydrate Metabolism

    PubMed Central

    Freitas, Fernanda Zanolli; Virgilio, Stela; Cupertino, Fernanda Barbosa; Kowbel, David John; Fioramonte, Mariana; Gozzo, Fabio Cesar; Glass, N. Louise; Bertolini, Maria Célia

    2016-01-01

    When exposed to stress conditions, all cells induce mechanisms resulting in an attempt to adapt to stress that involve proteins which, once activated, trigger cell responses by modulating specific signaling pathways. In this work, using a combination of pulldown assays and mass spectrometry analyses, we identified the Neurospora crassa SEB-1 transcription factor that binds to the Stress Response Element (STRE) under heat stress. Orthologs of SEB-1 have been functionally characterized in a few filamentous fungi as being involved in stress responses; however, the molecular mechanisms mediated by this transcription factor may not be conserved. Here, we provide evidences for the involvement of N. crassa SEB-1 in multiple cellular processes, including response to heat, as well as osmotic and oxidative stress. The Δseb-1 strain displayed reduced growth under these conditions, and genes encoding stress-responsive proteins were differentially regulated in the Δseb-1 strain grown under the same conditions. In addition, the SEB-1-GFP protein translocated from the cytosol to the nucleus under heat, osmotic, and oxidative stress conditions. SEB-1 also regulates the metabolism of the reserve carbohydrates glycogen and trehalose under heat stress, suggesting an interconnection between metabolism control and this environmental condition. We demonstrated that SEB-1 binds in vivo to the promoters of genes encoding glycogen metabolism enzymes and regulates their expression. A genome-wide transcriptional profile of the Δseb-1 strain under heat stress was determined by RNA-seq, and a broad range of cellular processes was identified that suggests a role for SEB-1 as a protein interconnecting these mechanisms. PMID:26994287

  1. Deep Carbon Cycling in the Deep Hydrosphere: Abiotic Organic Synthesis and Biogeochemical Cycling

    NASA Astrophysics Data System (ADS)

    Sherwood Lollar, B.; Sutcliffe, C. N.; Ballentine, C. J.; Warr, O.; Li, L.; Ono, S.; Wang, D. T.

    2014-12-01

    Research into the deep carbon cycle has expanded our understanding of the depth and extent of abiotic organic synthesis in the deep Earth beyond the hydrothermal vents of the deep ocean floor, and of the role of reduced gases in supporting deep subsurface microbial communities. Most recently, this research has expanded our understanding not only of the deep biosphere but the deep hydrosphere - identifying for the first time the extreme antiquity (millions to billions of years residence time) of deep saline fracture waters in the world's oldest rocks. Energy-rich saline fracture waters in the Precambrian crust that makes up more than 70% of the Earth's continental lithosphereprovide important constraints on our understanding of the extent of the crust that is habitable, on the time scales of hydrogeologic isolation (and conversely mixing) of fluids relevant to the deep carbon cycle, and on the geochemistry of substrates that sustain both abiotic organic synthesis and biogeochemical cycles driven by microbial communities. Ultimately the chemistry and hydrogeology of the deep hydrosphere will help define the limits for life in the subsurface and the boundary between the biotic-abiotic fringe. Using a variety of novel techniques including noble gas analysis, clumped isotopologues of methane, and compound specific isotope analysis of CHNOS, this research is addressing questions about the distribution of deep saline fluids in Precambrian rocks worldwide, the degree of interconnectedness of these potential biomes, the habitability of these fluids, and the biogeographic diversity of this new realm of the deep hydrosphere.

  2. A Central Role for Thiols in Plant Tolerance to Abiotic Stress

    PubMed Central

    Zagorchev, Lyuben; Seal, Charlotte E.; Kranner, Ilse; Odjakova, Mariela

    2013-01-01

    Abiotic stress poses major problems to agriculture and increasing efforts are being made to understand plant stress response and tolerance mechanisms and to develop new tools that underpin successful agriculture. However, the molecular mechanisms of plant stress tolerance are not fully understood, and the data available is incomplete and sometimes contradictory. Here, we review the significance of protein and non-protein thiol compounds in relation to plant tolerance of abiotic stress. First, the roles of the amino acids cysteine and methionine, are discussed, followed by an extensive discussion of the low-molecular-weight tripeptide, thiol glutathione, which plays a central part in plant stress response and oxidative signalling and of glutathione-related enzymes, including those involved in the biosynthesis of non-protein thiol compounds. Special attention is given to the glutathione redox state, to phytochelatins and to the role of glutathione in the regulation of the cell cycle. The protein thiol section focuses on glutaredoxins and thioredoxins, proteins with oxidoreductase activity, which are involved in protein glutathionylation. The review concludes with a brief overview of and future perspectives for the involvement of plant thiols in abiotic stress tolerance. PMID:23549272

  3. Screening for Abiotic Stress Tolerance in Rice: Salt, Cold, and Drought.

    PubMed

    Almeida, Diego M; Almadanim, M Cecília; Lourenço, Tiago; Abreu, Isabel A; Saibo, Nelson J M; Oliveira, M Margarida

    2016-01-01

    Rice (Oryza sativa) is the primary source of food for more than half of the world population. Most rice varieties are severely injured by abiotic stresses, with strong social and economic impact. Understanding rice responses to stress may help breeding for more tolerant varieties. However, papers dealing with stress experiments often describe very different experimental designs, thus making comparisons difficult. The use of identical setups is the only way to generate comparable data. This chapter is organized into three sections, describing the experimental conditions established at the Genomics of Plant Stress (GPlantS) unit of ITQB to assess the response of rice plants to three different abiotic stresses--high salinity, cold stress, and drought. All sections include a detailed description of the materials and methodology, as well as useful notes gathered from the GPlantS team's experience. We use rice seedlings as plants at this stage show high sensitivity to abiotic stresses. For the salt and cold stress assays we use hydroponic cultures, while for the drought assay plants are grown in soil and subjected to water withholding. All setups enable visual score determination and are suitable for sample collection along the imposition of stress. The proposed methodologies are simple and affordable to implement in most labs, allowing the discrimination of several rice genotypes at the molecular and phenotypic level.

  4. Including the spatial variability of metal speciation in the effect factor in life cycle impact assessment: Limits of the equilibrium partitioning method.

    PubMed

    Tromson, Clara; Bulle, Cécile; Deschênes, Louise

    2017-03-01

    In life cycle assessment (LCA), the potential terrestrial ecotoxicity effect of metals, calculated as the effect factor (EF), is usually extrapolated from aquatic ecotoxicological data using the equilibrium partitioning method (EqP) as it is more readily available than terrestrial data. However, when following the AMI recommendations (i.e. with at least enough species that represents three different phyla), there are not enough terrestrial data for which soil properties or metal speciation during ecotoxicological testing are specified to account for the influence of soil property variations on metal speciation when using this approach. Alternatively, the TBLM (Terrestrial Biotic Ligand Model) has been used to determine an EF that accounts for speciation, but is not available for metals; hence it cannot be consistently applied to metals in an LCA context. This paper proposes an approach to include metal speciation by regionalizing the EqP method for Cu, Ni and Zn with a geochemical speciation model (the Windermere Humic Aqueous Model 7.0), for 5213 soils selected from the Harmonized World Soil Database. Results obtained by this approach (EF(EqP)regionalized) are compared to the EFs calculated with the conventional EqP method, to the EFs based on available terrestrial data and to the EFs calculated with the TBLM (EF(TBLM)regionalized) when available. The spatial variability contribution of the EF to the overall spatial variability of the characterization factor (CF) has been analyzed. It was found that the EFs(EqP)regionalized show a significant spatial variability. The EFs calculated with the two non-regionalized methods (EqP and terrestrial data) fall within the range of the EFs(EqP)regionalized. The EFs(TBLM)regionalized cover a larger range of values than the EFs(EqP)regionalized but the two methods are not correlated. This paper highlights the importance of including speciation into the terrestrial EF and shows that using the regionalized EqP approach is not an

  5. Integrated metabolomics for abiotic stress responses in plants.

    PubMed

    Nakabayashi, Ryo; Saito, Kazuki

    2015-04-01

    Plants are considered to biosynthesize specialized (traditionally called secondary) metabolites to adapt to environmental stresses such as biotic and abiotic stresses. The majority of specialized metabolites induced by abiotic stress characteristically exhibit antioxidative activity in vitro, but their function in vivo is largely yet to be experimentally confirmed. In this review, we highlight recent advances in the identification of the role of abiotic stress-responsive specialized metabolites with an emphasis on flavonoids. Integrated 'omics' analysis, centered on metabolomics with a series of plant resources differing in their flavonoid accumulation, showed experimentally that flavonoids play a major role in antioxidation in vivo. In addition, the results also suggest the role of flavonoids in the vacuole. To obtain more in-depth insights, chemical and biological challenges need to be addressed for the identification of unknown specialized metabolites and their in vivo functions.

  6. Improved Tolerance to Various Abiotic Stresses in Transgenic Sweet Potato (Ipomoea batatas) Expressing Spinach Betaine Aldehyde Dehydrogenase

    PubMed Central

    Fan, Weijuan; Zhang, Min; Zhang, Hongxia; Zhang, Peng

    2012-01-01

    Abiotic stresses are critical delimiters for the increased productivity and cultivation expansion of sweet potato (Ipomoea batatas), a root crop with worldwide importance. The increased production of glycine betaine (GB) improves plant tolerance to various abiotic stresses without strong phenotypic changes, providing a feasible approach to improve stable yield production under unfavorable conditions. The gene encoding betaine aldehyde dehydrogenase (BADH) is involved in the biosynthesis of GB in plants, and the accumulation of GB by the heterologous overexpression of BADH improves abiotic stress tolerance in plants. This study is to improve sweet potato, a GB accumulator, resistant to multiple abiotic stresses by promoted GB biosynthesis. A chloroplastic BADH gene from Spinacia oleracea (SoBADH) was introduced into the sweet potato cultivar Sushu-2 via Agrobacterium-mediated transformation. The overexpression of SoBADH in the transgenic sweet potato improved tolerance to various abiotic stresses, including salt, oxidative stress, and low temperature. The increased BADH activity and GB accumulation in the transgenic plant lines under normal and multiple environmental stresses resulted in increased protection against cell damage through the maintenance of cell membrane integrity, stronger photosynthetic activity, reduced reactive oxygen species (ROS) production, and induction or activation of ROS scavenging by the increased activity of free radical-scavenging enzymes. The increased proline accumulation and systemic upregulation of many ROS-scavenging genes in stress-treated transgenic plants also indicated that GB accumulation might stimulate the ROS-scavenging system and proline biosynthesis via an integrative mechanism. This study demonstrates that the enhancement of GB biosynthesis in sweet potato is an effective and feasible approach to improve its tolerance to multiple abiotic stresses without causing phenotypic defects. This strategy for trait improvement in

  7. Characterization of a novel plantain Asr gene, MpAsr, that is regulated in response to infection of Fusarium oxysporum f. sp. cubense and abiotic stresses.

    PubMed

    Liu, Hai-Yan; Dai, Jin-Ran; Feng, Dong-Ru; Liu, Bing; Wang, Hong-Bin; Wang, Jin-Fa

    2010-03-01

    Asr (abscisic acid, stress, ripening induced) genes are typically upregulated by a wide range of factors, including drought, cold, salt, abscisic acid (ABA) and injury; in addition to plant responses to developmental and environmental signals. We isolated an Asr gene, MpAsr, from a suppression subtractive hybridization (SSH) cDNA library of cold induced plantain (Musa paradisiaca) leaves. MpAsr expression was upregulated in Fusarium oxysporum f. sp. cubense infected plantain leaves, peels and roots, suggesting that MpAsr plays a role in plantain pathogen response. In addition, a 581-bp putative promoter region of MpAsr was isolated via genome walking and cis-elements involved in abiotic stress and pathogen-related responses were detected in this same region. Furthermore, the MpAsr promoter demonstrated positive activity and inducibility in tobacco under F. oxysporum f. sp. cubense infection and ABA, cold, dehydration and high salt concentration treatments. Interestingly, transgenic Arabidopsis plants overexpressing MpAsr exhibited higher drought tolerance, but showed no significant decreased sensitivity to F. oxysporum f. sp. cubense. These results suggest that MpAsr might be involved in plant responses to both abiotic stress and pathogen attack.

  8. Abiotic methane formation during experimental serpentinization of olivine.

    PubMed

    McCollom, Thomas M

    2016-12-06

    Fluids circulating through actively serpentinizing systems are often highly enriched in methane (CH4). In many cases, the CH4 in these fluids is thought to derive from abiotic reduction of inorganic carbon, but the conditions under which this process can occur in natural systems remain unclear. In recent years, several studies have reported abiotic formation of CH4 during experimental serpentinization of olivine at temperatures at or below 200 °C. However, these results seem to contradict studies conducted at higher temperatures (300 °C to 400 °C), where substantial kinetic barriers to CH4 synthesis have been observed. Here, the potential for abiotic formation of CH4 from dissolved inorganic carbon during olivine serpentinization is reevaluated in a series of laboratory experiments conducted at 200 °C to 320 °C. A (13)C-labeled inorganic carbon source was used to unambiguously determine the origin of CH4 generated in the experiments. Consistent with previous high-temperature studies, the results indicate that abiotic formation of CH4 from reduction of dissolved inorganic carbon during the experiments is extremely limited, with nearly all of the observed CH4 derived from background sources. The results indicate that the potential for abiotic synthesis of CH4 in low-temperature serpentinizing environments may be much more limited than some recent studies have suggested. However, more extensive production of CH4 was observed in one experiment performed under conditions that allowed an H2-rich vapor phase to form, suggesting that shallow serpentinization environments where a separate gas phase is present may be more favorable for abiotic synthesis of CH4.

  9. Strategies to ameliorate abiotic stress-induced plant senescence.

    PubMed

    Gepstein, Shimon; Glick, Bernard R

    2013-08-01

    The plant senescence syndrome resembles, in many molecular and phenotypic aspects, plant responses to abiotic stresses. Both processes have an enormous negative global agro-economic impact and endanger food security worldwide. Premature plant senescence is the main cause of losses in grain filling and biomass yield due to leaf yellowing and deteriorated photosynthesis, and is also responsible for the losses resulting from the short shelf life of many vegetables and fruits. Under abiotic stress conditions the yield losses are often even greater. The primary challenge in agricultural sciences today is to develop technologies that will increase food production and sustainability of agriculture especially under environmentally limiting conditions. In this chapter, some of the mechanisms involved in abiotic stress-induced plant senescence are discussed. Recent studies have shown that crop yield and nutritional values can be altered as well as plant stress tolerance through manipulating the timing of senescence. It is often difficult to separate the effects of age-dependent senescence from stress-induced senescence since both share many biochemical processes and ultimately result in plant death. The focus of this review is on abiotic stress-induced senescence. Here, a number of the major approaches that have been developed to ameliorate some of the effects of abiotic stress-induced plant senescence are considered and discussed. Some approaches mimic the mechanisms already used by some plants and soil bacteria whereas others are based on development of new improved transgenic plants. While there may not be one simple strategy that can effectively decrease all losses of crop yield that accrue as a consequence of abiotic stress-induced plant senescence, some of the strategies that are discussed already show great promise.

  10. Abiotic methane formation during experimental serpentinization of olivine

    NASA Astrophysics Data System (ADS)

    McCollom, Thomas M.

    2016-12-01

    Fluids circulating through actively serpentinizing systems are often highly enriched in methane (CH4). In many cases, the CH4 in these fluids is thought to derive from abiotic reduction of inorganic carbon, but the conditions under which this process can occur in natural systems remain unclear. In recent years, several studies have reported abiotic formation of CH4 during experimental serpentinization of olivine at temperatures at or below 200 °C. However, these results seem to contradict studies conducted at higher temperatures (300 °C to 400 °C), where substantial kinetic barriers to CH4 synthesis have been observed. Here, the potential for abiotic formation of CH4 from dissolved inorganic carbon during olivine serpentinization is reevaluated in a series of laboratory experiments conducted at 200 °C to 320 °C. A 13C-labeled inorganic carbon source was used to unambiguously determine the origin of CH4 generated in the experiments. Consistent with previous high-temperature studies, the results indicate that abiotic formation of CH4 from reduction of dissolved inorganic carbon during the experiments is extremely limited, with nearly all of the observed CH4 derived from background sources. The results indicate that the potential for abiotic synthesis of CH4 in low-temperature serpentinizing environments may be much more limited than some recent studies have suggested. However, more extensive production of CH4 was observed in one experiment performed under conditions that allowed an H2-rich vapor phase to form, suggesting that shallow serpentinization environments where a separate gas phase is present may be more favorable for abiotic synthesis of CH4.

  11. Incidence, risk factors, and implemented prophylaxis of varicella zoster virus infection, including complicated varicella zoster virus and herpes simplex virus infections, in lenalidomide-treated multiple myeloma patients.

    PubMed

    König, C; Kleber, M; Reinhardt, H; Knop, S; Wäsch, R; Engelhardt, M

    2014-03-01

    In the era of high-dose chemotherapy and novel antimyeloma agents, the survival of multiple myeloma (MM) patients has substantially improved. Adverse effects, including infections, may however arise in the era of combination antimyeloma therapies. In general, MM patients have shown a risk of varicella zoster virus (VZV) infection of 1-4 %, increasing with bortezomib treatment or transplants, but whether immunomodulatory drugs also bear a risk of VZV/complicated herpes simplex virus (HSV) (e.g., VZV-encephalitis [VZV-E], disseminated VZV-infection [d-VZV-i], or conus-cauda syndrome [CCS]) has not been elucidated. We here assessed VZV, VZV-E, d-VZV-i, and CCS in 93 lenalidomide-treated MM patients, consecutively seen and treated in our department. Patients' data were analyzed via electronic medical record retrieval within our research data warehouse as described previously. Of the 93 MM patients receiving lenalidomide, 10 showed VZV or other complicated VZV/HSV infections. These VZV patients showed defined risk factors as meticulously assessed, including suppressed lymphocyte subsets, substantial cell-mediated immune defects, and compromised humoral immune response. Due to our findings-and in line with an aciclovir prophylaxis in bortezomib and stem cell transplant protocols-we introduced a routine aciclovir prophylaxis in our lenalidomide protocols in May 2012 to minimize adverse events and to avoid discontinuation of lenalidomide treatment. Since then, we have observed no case of VZV/complicated HSV infection. Based on our data, we encourage other centers to also focus on these observations, assess viral infections, and-in those centers facilitating a research data warehouse-advocate an analogue data review as an appropriate multicenter approach.

  12. Synergistic in vitro antioxidant activity and observational clinical trial of F105, a phytochemical formulation including Citrus bergamia, in subjects with moderate cardiometabolic risk factors.

    PubMed

    Babish, John G; Dahlberg, Clinton J; Ou, Joseph J; Keller, William J; Gao, Wei; Kaadige, Mohan R; Brabazon, Holly; Lamb, Joseph; Soudah, Hani C; Kou, Xiaolan; Zhang, Zhe; Pacioretty, Linda M; Tripp, Matthew L

    2016-12-01

    We examined the clinical safety and efficacy of F105 in 11 subjects with moderate dyslipidemia. F105 is a combination of bergamot fruit extract (Citrus bergamia, BFE) and 9 phytoextracts selected for their ability to improve the antioxidant and anti-inflammatory activity of BFE. In vitro F105 exhibited a synergistic inhibition of oxygen radical absorbing capacity, peroxynitrite formation, and myeloperoxidase activity. Following 12 weeks of F105 daily, no treatment-related adverse events or changes in body mass were seen. Statistically significant changes were noted in total cholesterol (-7.3%), LDL-cholesterol (-10%), non-HDL cholesterol (-7.1%), cholesterol/HDL (-26%), and apolipoprotein B (-2.8%). A post hoc analysis of 8 subjects with HbA1c > 5.4 and HOMA-IR score > 2 or elevated triglycerides revealed additional statistically significant changes in addition to those previously observed in all subjects including triglycerides (-27%), oxLDL (-19%), LDL/HDL (-25%), triglycerides/HDL (-27%), oxLDL/HDL (-25%), and PAI-1 (-37%). A follow-up case report of a 70-year-old female patient, nonresponsive to statin therapy and placed on F105 daily, demonstrated improved cardiometabolic variables over 12 weeks similar to the subgroup. In summary, F105 was clinically well-tolerated and effective for ameliorating dyslipidemia in subjects with moderate cardiometabolic risk factors, particularly in the individuals with HbA1c > 5.4%.

  13. Nitric oxide signaling in plant responses to abiotic stresses.

    PubMed

    Qiao, Weihua; Fan, Liu-Min

    2008-10-01

    Nitric oxide (NO) plays important roles in diverse physiological processes in plants. NO can provoke both beneficial and harmful effects, which depend on the concentration and location of NO in plant cells. This review is focused on NO synthesis and the functions of NO in plant responses to abiotic environmental stresses. Abiotic stresses mostly induce NO production in plants. NO alleviates the harmfulness of reactive oxygen species, and reacts with other target molecules, and regulates the expression of stress responsive genes under various stress conditions.

  14. Clinicopathological Characteristics of Gynecological Cancer Associated with Hypoxia-Inducible Factor 1α Expression: A Meta-Analysis Including 6,612 Subjects

    PubMed Central

    Ma, Xiaowei; Liang, Xiaowen; Liu, Xin; Wang, Yu

    2015-01-01

    Background Gynecological cancer is characterized by tumor hypoxia. However, the role of hypoxia-inducible factor 1α (HIF-1α) in gynecological cancer remains unclear. Method Electronic databases including Cochrane Library, PUBMED, Web of Knowledge and clinical trial registries were searched from inception through October 2014 for published, case-control studies assessing the association between HIF-1α and the clinicopathological characteristics of gynecological cancer. We pooled results from 59 studies using fixed or random-effects models and present results as odds ratios (ORs) following the PRISMA guidelines. Results Our meta-analysis, which included 6,612 women, demonstrated that the expression of HIF-1α was associated with the clinicopathological characteristics of gynecological cancer. The expression of HIF-1α in cancer or borderline tissue was significantly higher than that in normal tissue (cancer vs. normal: odds ratio (OR) =9.59, 95% confidence interval (CI): 5.97, 15.39, p<0.00001; borderline vs. normal: OR=4.13, 95% (CI): 2.43, 7.02, p<0.00001; cancer vs. borderline: OR=2.70, 95% (CI): 1.69, 4.31, p<0.0001). The expression of HIF-1α in III‒IV stage or lymph node metastasis was significantly higher than that in I‒II stage or that without lymph node metastasis, respectively (OR=2.66, 95% (CI): 1.87,3.79, p<0.00001; OR= 3.98, 95% (CI): 2.10,12.89, p<0.0001). HIF-1α was associated with histological grade of cancer (Grade 3 vs. Grade 1: OR=3.77, 95% (CI): 2.76,5.16, p<0.00001; Grade 3 vs. Grade 2: OR=1.62, 95% (CI): 1.20,2.19, p=0.002; Grade 2 vs. Grade 1: OR=2.34, 95% (CI): 1.82,3.00, p<0.00001),5-years disease free survival (DFS) rates (OR=2.93, 95% (CI):1.43,6.01, p=0.001) and 5-years overall survival (OS) rates (OR=5.53, 95% (CI): 2.48,12.31, p<0.0001). Conclusion HIF-1α is associated with the malignant degree, FIGO stage, histological grade, lymph node metastasis, 5-years survival rate and recurrence rate of gynecological cancer. It may play

  15. Laser Microdissection Unravels Cell-Type-Specific Transcription in Arbuscular Mycorrhizal Roots, Including CAAT-Box Transcription Factor Gene Expression Correlating with Fungal Contact and Spread1[W

    PubMed Central

    Hogekamp, Claudia; Arndt, Damaris; Pereira, Patrícia A.; Becker, Jörg D.; Hohnjec, Natalija; Küster, Helge

    2011-01-01

    Arbuscular mycorrhizae (AM) are the most widespread symbioses on Earth, promoting nutrient supply of most terrestrial plant species. To unravel gene expression in defined stages of Medicago truncatula root colonization by AM fungi, we here combined genome-wide transcriptome profiling based on whole mycorrhizal roots with real-time reverse transcription-PCR experiments that relied on characteristic cell types obtained via laser microdissection. Our genome-wide approach delivered a core set of 512 genes significantly activated by the two mycorrhizal fungi Glomus intraradices and Glomus mossae. Focusing on 62 of these genes being related to membrane transport, signaling, and transcriptional regulation, we distinguished whether they are activated in arbuscule-containing or the neighboring cortical cells harboring fungal hyphae. In addition, cortical cells from nonmycorrhizal roots served as a reference for gene expression under noncolonized conditions. Our analysis identified 25 novel arbuscule-specific genes and 37 genes expressed both in the arbuscule-containing and the adjacent cortical cells colonized by fungal hyphae. Among the AM-induced genes specifying transcriptional regulators were two members encoding CAAT-box binding transcription factors (CBFs), designated MtCbf1 and MtCbf2. Promoter analyses demonstrated that both genes were already activated by the first physical contact between the symbionts. Subsequently, and corresponding to our cell-type expression patterns, they were progressively up-regulated in those cortical areas colonized by fungal hyphae, including the arbuscule-containing cells. The encoded CBFs thus represent excellent candidates for regulators that mediate a sequential reprogramming of root tissues during the establishment of an AM symbiosis. PMID:22034628

  16. Laser microdissection unravels cell-type-specific transcription in arbuscular mycorrhizal roots, including CAAT-box transcription factor gene expression correlating with fungal contact and spread.

    PubMed

    Hogekamp, Claudia; Arndt, Damaris; Pereira, Patrícia A; Becker, Jörg D; Hohnjec, Natalija; Küster, Helge

    2011-12-01

    Arbuscular mycorrhizae (AM) are the most widespread symbioses on Earth, promoting nutrient supply of most terrestrial plant species. To unravel gene expression in defined stages of Medicago truncatula root colonization by AM fungi, we here combined genome-wide transcriptome profiling based on whole mycorrhizal roots with real-time reverse transcription-PCR experiments that relied on characteristic cell types obtained via laser microdissection. Our genome-wide approach delivered a core set of 512 genes significantly activated by the two mycorrhizal fungi Glomus intraradices and Glomus mossae. Focusing on 62 of these genes being related to membrane transport, signaling, and transcriptional regulation, we distinguished whether they are activated in arbuscule-containing or the neighboring cortical cells harboring fungal hyphae. In addition, cortical cells from nonmycorrhizal roots served as a reference for gene expression under noncolonized conditions. Our analysis identified 25 novel arbuscule-specific genes and 37 genes expressed both in the arbuscule-containing and the adjacent cortical cells colonized by fungal hyphae. Among the AM-induced genes specifying transcriptional regulators were two members encoding CAAT-box binding transcription factors (CBFs), designated MtCbf1 and MtCbf2. Promoter analyses demonstrated that both genes were already activated by the first physical contact between the symbionts. Subsequently, and corresponding to our cell-type expression patterns, they were progressively up-regulated in those cortical areas colonized by fungal hyphae, including the arbuscule-containing cells. The encoded CBFs thus represent excellent candidates for regulators that mediate a sequential reprogramming of root tissues during the establishment of an AM symbiosis.

  17. Genetic mapping of abiotic stress responses in sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to rich genetic diversity for tolerance to various abiotic stress conditions, sorghum is an ideal system for genetic mapping and elucidation of genome regions that confer such response among cereal crops. Coupled with the development of DNA marker technologies and most recently the sequencing o...

  18. ABIOTIC DEGRADATION OF TRICHLOROETHYLENE UNDER THERMAL REMEDIATION CONDITIONS

    EPA Science Inventory

    The degradation of TCE (C2HCl3) to carbon dioxide (CO2) and chloride (Cl-) has been reported to occur during thermal remediation of subsurface environments. The overall goal of this study was to evaluate abiotic degradation of TCE at el...

  19. The potential of lactic acid bacteria to colonize biotic and abiotic surfaces and the investigation of their interactions and mechanisms.

    PubMed

    Arena, Mattia Pia; Capozzi, Vittorio; Spano, Giuseppe; Fiocco, Daniela

    2017-04-01

    Lactic acid bacteria (LAB) are a heterogeneous group of Gram-positive bacteria that comprise several species which have evolved in close association with humans (food and lifestyle). While their use to ferment food dates back to very ancient times, in the last decades, LAB have attracted much attention for their documented beneficial properties and for potential biomedical applications. Some LAB are commensal that colonize, stably or transiently, host mucosal surfaces, inlcuding the gut, where they may contribute to host health. In this review, we present and discuss the main factors enabling LAB adaptation to such lifestyle, including the gene reprogramming accompanying gut colonization, the specific bacterial components involved in adhesion and interaction with host, and how the gut niche has shaped the genome of intestine-adapted species. Moreover, the capacity of LAB to colonize abiotic surfaces by forming structured communities, i.e., biofilms, is briefly discussed, taking into account the main bacterial and environmental factors involved, particularly in relation to food-related environments. The vast spread of LAB surface-associated communities and the ability to control their occurrence hold great potentials for human health and food safety biotechnologies.

  20. Abscisic Acid Signaling and Abiotic Stress Tolerance in Plants: A Review on Current Knowledge and Future Prospects

    PubMed Central

    Vishwakarma, Kanchan; Upadhyay, Neha; Kumar, Nitin; Yadav, Gaurav; Singh, Jaspreet; Mishra, Rohit K.; Kumar, Vivek; Verma, Rishi; Upadhyay, R. G.; Pandey, Mayank; Sharma, Shivesh

    2017-01-01

    Abiotic stress is one of the severe stresses of environment that lowers the growth and yield of any crop even on irrigated land throughout the world. A major phytohormone abscisic acid (ABA) plays an essential part in acting toward varied range of stresses like heavy metal stress, drought, thermal or heat stress, high level of salinity, low temperature, and radiation stress. Its role is also elaborated in various developmental processes including seed germination, seed dormancy, and closure of stomata. ABA acts by modifying the expression level of gene and subsequent analysis of cis- and trans-acting regulatory elements of responsive promoters. It also interacts with the signaling molecules of processes involved in stress response and development of seeds. On the whole, the stress to a plant can be susceptible or tolerant by taking into account the coordinated activities of various stress-responsive genes. Numbers of transcription factor are involved in regulating the expression of ABA responsive genes by acting together with their respective cis-acting elements. Hence, for improvement in stress-tolerance capacity of plants, it is necessary to understand the mechanism behind it. On this ground, this article enlightens the importance and role of ABA signaling with regard to various stresses as well as regulation of ABA biosynthetic pathway along with the transcription factors for stress tolerance. PMID:28265276

  1. The transcriptional network of WRKY53 in cereals links oxidative responses to biotic and abiotic stress inputs.

    PubMed

    Van Eck, Leon; Davidson, Rebecca M; Wu, Shuchi; Zhao, Bingyu Y; Botha, Anna-Maria; Leach, Jan E; Lapitan, Nora L V

    2014-06-01

    The transcription factor WRKY53 is expressed during biotic and abiotic stress responses in cereals, but little is currently known about its regulation, structure and downstream targets. We sequenced the wheat ortholog TaWRKY53 and its promoter region, which revealed extensive similarity in gene architecture and cis-acting regulatory elements to the rice ortholog OsWRKY53, including the presence of stress-responsive abscisic acid-responsive elements (ABRE) motifs and GCC-boxes. Four proteins interacted with the WRKY53 promoter in yeast one-hybrid assays, suggesting that this gene can receive inputs from diverse stress-related pathways such as calcium signalling and senescence, and environmental cues such as drought and ultraviolet radiation. The Ser/Thr receptor kinase ORK10/LRK10 and the apoplastic peroxidase POC1 are two downstream targets for regulation by the WRKY53 transcription factor, predicted based on the presence of W-box motifs in their promoters and coregulation with WRKY53, and verified by electrophoretic mobility shift assay (EMSA). Both ORK10/LRK10 and POC1 are upregulated during cereal responses to pathogens and aphids and important components of the oxidative burst during the hypersensitive response. Taken with our yeast two-hybrid assay which identified a strong protein-protein interaction between microsomal glutathione S-transferase 3 and WRKY53, this implies that the WRKY53 transcriptional network regulates oxidative responses to a wide array of stresses.

  2. Evaluating reaction pathways of hydrothermal abiotic organic synthesis at elevated temperatures and pressures using carbon isotopes

    NASA Astrophysics Data System (ADS)

    Fu, Qi; Socki, Richard A.; Niles, Paul B.

    2015-04-01

    Experiments were performed to better understand the role of environmental factors on reaction pathways and corresponding carbon isotope fractionations during abiotic hydrothermal synthesis of organic compounds using piston cylinder apparatus at 750 °C and 5.5 kbars. Chemical compositions of experimental products and corresponding carbon isotopic values were obtained by a Pyrolysis-GC-MS-IRMS system. Alkanes (methane and ethane), straight-chain saturated alcohols (ethanol and n-butanol) and monocarboxylic acids (formic and acetic acids) were generated with ethanol being the only organic compound with higher δ13C than CO2. CO was not detected in experimental products owing to the favorable water-gas shift reaction under high water pressure conditions. The pattern of δ13C values of CO2, carboxylic acids and alkanes are consistent with their equilibrium isotope relationships: CO2 > carboxylic acids > alkanes, but the magnitude of the fractionation among them is higher than predicted isotope equilibrium values. In particular, the isotopic fractionation between CO2 and CH4 remained constant at ∼31‰, indicating a kinetic effect during CO2 reduction processes. No "isotope reversal" of δ13C values for alkanes or carboxylic acids was observed, which indicates a different reaction pathway than what is typically observed during Fischer-Tropsch synthesis under gas phase conditions. Under constraints imposed in experiments, the anomalous 13C isotope enrichment in ethanol suggests that hydroxymethylene is the organic intermediate, and that the generation of other organic compounds enriched in 12C were facilitated by subsequent Rayleigh fractionation of hydroxymethylene reacting with H2 and/or H2O. Carbon isotope fractionation data obtained in this study are instrumental in assessing the controlling factors on abiotic formation of organic compounds in hydrothermal systems. Knowledge on how environmental conditions affect reaction pathways of abiotic synthesis of organic

  3. Seed treatment with Trichoderma harzianum alleviates biotic, abiotic, and physiological stresses in germinating seeds and seedlings.

    PubMed

    Mastouri, Fatemeh; Björkman, Thomas; Harman, Gary E

    2010-11-01

    Trichoderma spp. are endophytic plant symbionts that are widely used as seed treatments to control diseases and to enhance plant growth and yield. Although some recent work has been published on their abilities to alleviate abiotic stresses, specific knowledge of mechanisms, abilities to control multiple plant stress factors, their effects on seed and seedlings is lacking. We examined the effects of seed treatment with T. harzianum strain T22 on germination of seed exposed to biotic stress (seed and seedling disease caused by Pythium ultimum) and abiotic stresses (osmotic, salinity, chilling, or heat stress). We also evaluated the ability of the beneficial fungus to overcome physiological stress (poor seed quality induced by seed aging). If seed were not under any of the stresses noted above, T22 generally had little effect upon seedling performance. However, under stress, treated seed germinated consistently faster and more uniformly than untreated seeds whether the stress was osmotic, salt, or suboptimal temperatures. The consistent response to varying stresses suggests a common mechanism through which the plant-fungus association enhances tolerance to a wide range of abiotic stresses as well as biotic stress. A common factor that negatively affects plants under these stress conditions is accumulation of toxic reactive oxygen species (ROS), and we tested the hypothesis that T22 reduced damages resulting from accumulation of ROS in stressed plants. Treatment of seeds reduced accumulation of lipid peroxides in seedlings under osmotic stress or in aged seeds. In addition, we showed that the effect of exogenous application of an antioxidant, glutathione, or application of T22, resulted in a similar positive effect on seed germination under osmotic stress or in aged seed. This evidence supports the model that T. harzianum strain T22 increases seedling vigor and ameliorates stress by inducing physiological protection in plants against oxidative damage.

  4. Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

    SciTech Connect

    Domagal-Goldman, Shawn D.; Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S.

    2014-09-10

    The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

  5. Genome-wide identification of abiotic stress-regulated and novel microRNAs in mulberry leaf.

    PubMed

    Wu, Ping; Han, Shaohua; Zhao, Weiguo; Chen, Tao; Zhou, Jiachun; Li, Long

    2015-10-01

    As the most important food plant for sericultural industry, mulberry trees have to suffer from a wide range of abiotic and biotic stresses, such as drought and high salinity. MicroRNAs (miRNAs) have been proved to play important roles in abiotic stresses regulation in many plants. However, there are seldom reports on the miRNAs expression profiles upon abiotic challenges in mulberry. In this study, three small RNA libraries from mulberry leaf tissue with or without drought or salt treatment were constructed and deep sequenced. Total of 48 conserved miRNAs (including miRNA*) and 162 novel miRNAs were identified (processing precision value>0.1). A total of 270 and 1963 target genes were predicted for conserved miRNAs and novel miRNAs, respectively. 13 differentially expressed miRNAs were detected under drought or salt stresses by deep sequencing and qRT-PCR. 5' RLM-RACE validated Morus 013341 to be the target gene of miR-395a. Our results provided initial clue to further study molecular mechanism on abiotic stresses regulation in mulberry.

  6. QlicRice: a web interface for abiotic stress responsive QTL and loci interaction channels in rice

    PubMed Central

    Smita, Shuchi; Lenka, Sangram Keshari; Katiyar, Amit; Jaiswal, Pankaj; Preece, Justin; Bansal, Kailash Chander

    2011-01-01

    The QlicRice database is designed to host publicly accessible, abiotic stress responsive quantitative trait loci (QTLs) in rice (Oryza sativa) and their corresponding sequenced gene loci. It provides a platform for the data mining of abiotic stress responsive QTLs, as well as browsing and annotating associated traits, their location on a sequenced genome, mapped expressed sequence tags (ESTs) and tissue and growth stage-specific expressions on the whole genome. Information on QTLs related to abiotic stresses and their corresponding loci from a genomic perspective has not yet been integrated on an accessible, user-friendly platform. QlicRice offers client-responsive architecture to retrieve meaningful biological information—integrated and named ‘Qlic Search’—embedded in a query phrase autocomplete feature, coupled with multiple search options that include trait names, genes and QTL IDs. A comprehensive physical and genetic map and vital statistics have been provided in a graphical manner for deciphering the position of QTLs on different chromosomes. A convenient and intuitive user interface have been designed to help users retrieve associations to agronomically important QTLs on abiotic stress response in rice. Database URL: http://nabg.iasri.res.in:8080/qlic-rice/. PMID:21965557

  7. QlicRice: a web interface for abiotic stress responsive QTL and loci interaction channels in rice.

    PubMed

    Smita, Shuchi; Lenka, Sangram Keshari; Katiyar, Amit; Jaiswal, Pankaj; Preece, Justin; Bansal, Kailash Chander

    2011-01-01

    The QlicRice database is designed to host publicly accessible, abiotic stress responsive quantitative trait loci (QTLs) in rice (Oryza sativa) and their corresponding sequenced gene loci. It provides a platform for the data mining of abiotic stress responsive QTLs, as well as browsing and annotating associated traits, their location on a sequenced genome, mapped expressed sequence tags (ESTs) and tissue and growth stage-specific expressions on the whole genome. Information on QTLs related to abiotic stresses and their corresponding loci from a genomic perspective has not yet been integrated on an accessible, user-friendly platform. QlicRice offers client-responsive architecture to retrieve meaningful biological information--integrated and named 'Qlic Search'--embedded in a query phrase autocomplete feature, coupled with multiple search options that include trait names, genes and QTL IDs. A comprehensive physical and genetic map and vital statistics have been provided in a graphical manner for deciphering the position of QTLs on different chromosomes. A convenient and intuitive user interface have been designed to help users retrieve associations to agronomically important QTLs on abiotic stress response in rice. Database URL: http://nabg.iasri.res.in:8080/qlic-rice/.

  8. Transcriptional Profiling Reveals Novel Interactions between Wounding, Pathogen, Abiotic Stress, and Hormonal Responses in Arabidopsis1[w

    PubMed Central

    Cheong, Yong Hwa; Chang, Hur-Song; Gupta, Rajeev; Wang, Xun; Zhu, Tong; Luan, Sheng

    2002-01-01

    Mechanical wounding not only damages plant tissues, but also provides pathways for pathogen invasion. To understand plant responses to wounding at a genomic level, we have surveyed the transcriptional response of 8,200 genes in Arabidopsis plants. Approximately 8% of these genes were altered by wounding at steady-state mRNA levels. Studies of expression patterns of these genes provide new information on the interactions between wounding and other signals, including pathogen attack, abiotic stress factors, and plant hormones. For example, a number of wound-responsive genes encode proteins involved in pathogen response. These include signaling molecules for the pathogen resistance pathway and enzymes required for cell wall modification and secondary metabolism. Many osmotic stress- and heat shock-regulated genes were highly responsive to wounding. Although a number of genes involved in ethylene, jasmonic acid, and abscisic acid pathways were activated, many in auxin responses were suppressed by wounding. These results further dissected the nature of mechanical wounding as a stress signal and identified new genes that may play a role in wounding and other signal transduction pathways. PMID:12068110

  9. Microarray: gateway to unravel the mystery of abiotic stresses in plants.

    PubMed

    Gul, Ambreen; Ahad, Ammara; Akhtar, Sidra; Ahmad, Zarnab; Rashid, Bushra; Husnain, Tayyab

    2016-04-01

    Environmental factors, such as drought, salinity, extreme temperature, ozone poisoning, metal toxicity etc., significantly affect crops. To study these factors and to design a possible remedy, biological experimental data concerning these crops requires the quantification of gene expression and comparative analyses at high throughput level. Development of microarrays is the platform to study the differential expression profiling of the targeted genes. This technology can be applied to gene expression studies, ranging from individual genes to whole genome level. It is now possible to perform the quantification of the differential expression of genes on a glass slide in a single experiment. This review documents recently published reports on the use of microarrays for the identification of genes in different plant species playing their role in different cellular networks under abiotic stresses. The regulation pattern of differentially-expressed genes, individually or in group form, may help us to study different pathways and functions at the cellular and molecular level. These studies can provide us with a lot of useful information to unravel the mystery of abiotic stresses in important crop plants.

  10. Human factors issues and approaches in the spatial layout of a space station control room, including the use of virtual reality as a design analysis tool

    NASA Technical Reports Server (NTRS)

    Hale, Joseph P., II

    1994-01-01

    Human Factors Engineering support was provided for the 30% design review of the late Space Station Freedom Payload Control Area (PCA). The PCA was to be the payload operations control room, analogous to the Spacelab Payload Operations Control Center (POCC). This effort began with a systematic collection and refinement of the relevant requirements driving the spatial layout of the consoles and PCA. This information was used as input for specialized human factors analytical tools and techniques in the design and design analysis activities. Design concepts and configuration options were developed and reviewed using sketches, 2-D Computer-Aided Design (CAD) drawings, and immersive Virtual Reality (VR) mockups.

  11. Modeling regeneration responses of big sagebrush (Artemisia tridentata) to abiotic conditions

    USGS Publications Warehouse

    Schlaepfer, Daniel R.; Lauenroth, William K.; Bradford, John B.

    2014-01-01

    Ecosystems dominated by big sagebrush, Artemisia tridentata Nuttall (Asteraceae), which are the most widespread ecosystems in semiarid western North America, have been affected by land use practices and invasive species. Loss of big sagebrush and the decline of associated species, such as greater sage-grouse, are a concern to land managers and conservationists. However, big sagebrush regeneration remains difficult to achieve by restoration and reclamation efforts and there is no regeneration simulation model available. We present here the first process-based, daily time-step, simulation model to predict yearly big sagebrush regeneration including relevant germination and seedling responses to abiotic factors. We estimated values, uncertainty, and importance of 27 model parameters using a total of 1435 site-years of observation. Our model explained 74% of variability of number of years with successful regeneration at 46 sites. It also achieved 60% overall accuracy predicting yearly regeneration success/failure. Our results identify specific future research needed to improve our understanding of big sagebrush regeneration, including data at the subspecies level and improved parameter estimates for start of seed dispersal, modified wet thermal-time model of germination, and soil water potential influences. We found that relationships between big sagebrush regeneration and climate conditions were site specific, varying across the distribution of big sagebrush. This indicates that statistical models based on climate are unsuitable for understanding range-wide regeneration patterns or for assessing the potential consequences of changing climate on sagebrush regeneration and underscores the value of this process-based model. We used our model to predict potential regeneration across the range of sagebrush ecosystems in the western United States, which confirmed that seedling survival is a limiting factor, whereas germination is not. Our results also suggested that modeled

  12. Soil respiration in the cold desert environment of the Colorado Plateau (USA): Abiotic regulators and thresholds

    USGS Publications Warehouse

    Fernandez, D.P.; Neff, J.C.; Belnap, J.; Reynolds, R.L.

    2006-01-01

    Decomposition is central to understanding ecosystem carbon exchange and nutrient-release processes. Unlike mesic ecosystems, which have been extensively studied, xeric landscapes have received little attention; as a result, abiotic soil-respiration regulatory processes are poorly understood in xeric environments. To provide a more complete and quantitative understanding about how abiotic factors influence soil respiration in xeric ecosystems, we conducted soil- respiration and decomposition-cloth measurements in the cold desert of southeast Utah. Our study evaluated when and to what extent soil texture, moisture, temperature, organic carbon, and nitrogen influence soil respiration and examined whether the inverse-texture hypothesis applies to decomposition. Within our study site, the effect of texture on moisture, as described by the inverse texture hypothesis, was evident, but its effect on decomposition was not. Our results show temperature and moisture to be the dominant abiotic controls of soil respiration. Specifically, temporal offsets in temperature and moisture conditions appear to have a strong control on soil respiration, with the highest fluxes occurring in spring when temperature and moisture were favorable. These temporal offsets resulted in decomposition rates that were controlled by soil moisture and temperature thresholds. The highest fluxes of CO2 occurred when soil temperature was between 10 and 16??C and volumetric soil moisture was greater than 10%. Decomposition-cloth results, which integrate decomposition processes across several months, support the soil-respiration results and further illustrate the seasonal patterns of high respiration rates during spring and low rates during summer and fall. Results from this study suggest that the parameters used to predict soil respiration in mesic ecosystems likely do not apply in cold-desert environments. ?? Springer 2006.

  13. Methylglyoxal: An Emerging Signaling Molecule in Plant Abiotic Stress Responses and Tolerance

    PubMed Central

    Hoque, Tahsina S.; Hossain, Mohammad A.; Mostofa, Mohammad G.; Burritt, David J.; Fujita, Masayuki; Tran, Lam-Son P.

    2016-01-01

    The oxygenated short aldehyde methylglyoxal (MG) is produced in plants as a by-product of a number of metabolic reactions, including elimination of phosphate groups from glycolysis intermediates dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. MG is mostly detoxified by the combined actions of the enzymes glyoxalase I and glyoxalase II that together with glutathione make up the glyoxalase system. Under normal growth conditions, basal levels of MG remain low in plants; however, when plants are exposed to abiotic stress, MG can accumulate to much higher levels. Stress-induced MG functions as a toxic molecule, inhibiting different developmental processes, including seed germination, photosynthesis and root growth, whereas MG, at low levels, acts as an important signaling molecule, involved in regulating diverse events, such as cell proliferation and survival, control of the redox status of cells, and many other aspects of general metabolism and cellular homeostases. MG can modulate plant stress responses by regulating stomatal opening and closure, the production of reactive oxygen species, cytosolic calcium ion concentrations, the activation of inward rectifying potassium channels and the expression of many stress-responsive genes. MG appears to play important roles in signal transduction by transmitting and amplifying cellular signals and functions that promote adaptation of plants growing under adverse environmental conditions. Thus, MG is now considered as a potential biochemical marker for plant abiotic stress tolerance, and is receiving considerable attention by the scientific community. In this review, we will summarize recent findings regarding MG metabolism in plants under abiotic stress, and evaluate the concept of MG signaling. In addition, we will demonstrate the importance of giving consideration to MG metabolism and the glyoxalase system, when investigating plant adaptation and responses to various environmental stresses. PMID:27679640

  14. Modulation of thiamine metabolism in Zea mays seedlings under conditions of abiotic stress.

    PubMed

    Rapala-Kozik, Maria; Kowalska, Ewa; Ostrowska, Katarzyna

    2008-01-01

    The responses of plants to abiotic stress involve the up-regulation of numerous metabolic pathways, including several major routes that engage thiamine diphosphate (TDP)-dependent enzymes. This suggests that the metabolism of thiamine (vitamin B1) and its phosphate esters in plants may be modulated under various stress conditions. In the present study, Zea mays seedlings were used as a model system to analyse for any relation between the plant response to abiotic stress and the properties of thiamine biosynthesis and activation. Conditions of drought, high salt, and oxidative stress were induced by polyethylene glycol, sodium chloride, and hydrogen peroxide, respectively. The expected increases in the abscisic acid levels and in the activities of antioxidant enzymes including catalase, ascorbate peroxidase, and glutathione reductase were found under each stress condition. The total thiamine compound content in the maize seedling leaves increased under each stress condition applied, with the strongest effects on these levels observed under the oxidative stress treatment. This increase was also found to be associated with changes in the relative distribution of free thiamine, thiamine monophosphate (TMP), and TDP. Surprisingly, the activity of the thiamine synthesizing enzyme, TMP synthase, responded poorly to abiotic stress, in contrast to the significant enhancement found for the activities of the TDP synthesizing enzyme, thiamine pyrophosphokinase, and a number of the TDP/TMP phosphatases. Finally, a moderate increase in the activity of transketolase, one of the major TDP-dependent enzymes, was detectable under conditions of salt and oxidative stress. These findings suggest a role of thiamine metabolism in the plant response to environmental stress.

  15. Maternal, social and abiotic environmental effects on growth vary across life stages in a cooperative mammal.

    PubMed

    English, Sinead; Bateman, Andrew W; Mares, Rafael; Ozgul, Arpat; Clutton-Brock, Tim H

    2014-03-01

    Resource availability plays a key role in driving variation in somatic growth and body condition, and the factors determining access to resources vary considerably across life stages. Parents and carers may exert important influences in early life, when individuals are nutritionally dependent, with abiotic environmental effects having stronger influences later in development as individuals forage independently. Most studies have measured specific factors influencing growth across development or have compared relative influences of different factors within specific life stages. Such studies may not capture whether early-life factors continue to have delayed effects at later stages, or whether social factors change when individuals become nutritionally independent and adults become competitors for, rather than providers of, food. Here, we examined variation in the influence of the abiotic, social and maternal environment on growth across life stages in a wild population of cooperatively breeding meerkats. Cooperatively breeding vertebrates are ideal for investigating environmental influences on growth. In addition to experiencing highly variable abiotic conditions, cooperative breeders are typified by heterogeneity both among breeders, with mothers varying in age and social status, and in the number of carers present. Recent rainfall had a consistently marked effect on growth across life stages, yet other seasonal terms only influenced growth during stages when individuals were growing fastest. Group size and maternal dominance status had positive effects on growth during the period of nutritional dependence on carers, but did not influence mass at emergence (at 1 month) or growth at independent stages (>4 months). Pups born to older mothers were lighter at 1 month of age and subsequently grew faster as subadults. Males grew faster than females during the juvenile and subadult stage only. Our findings demonstrate the complex ways in which the external environment

  16. Biogeomorphology of a Mojave Desert landscape - Configurations and feedbacks of abiotic and biotic land surfaces during landform evolution

    NASA Astrophysics Data System (ADS)

    Pietrasiak, Nicole; Drenovsky, Rebecca E.; Santiago, Louis S.; Graham, Robert C.

    2014-02-01

    Terrestrial ecosystems can be more holistically understood by investigating the morphology of landscape mosaics, the assemblage of their ecological communities, and the linkages and feedbacks between the mosaics and communities. The overarching objectives of this study were to: (1) study the abiotic and biotic configurations of landform units as mosaics within a Mojave Desert chronosequence; and (2) elucidate their potential feedbacks, interactions, and dynamics during landform evolution. Seven landform units distributed over three geomorphic ages were identified, including: young bars and swales; intermediate-aged flattened bars, flattened swales, and bioturbation units; and old desert pavements and shrub zones. These landform units were characterized according to abiotic and biotic land surface properties. Landform units were statistically distinct and predictable based on a specific suite of abiotic and biotic properties. Vascular plant functional group and biological soil crust community diversity varied with geomorphology, with greatest diversity associated with bars and shrub zones and lowest diversity associated with desert pavements. Biological soil crust communities were controlled by geomorphic age, surface rock size, and protruding rocks with young bar units having the highest abundance and diversity. Perennial forbs were observed in old shrub zones with small rocks and few protruding rocks. A high clast density and a finer-sized clast distribution were found particularly in desert pavements and flattened swales, and generally inhibited biological soil crust and plant cover. Evolutionary trajectories for landforms of a lower piedmont landscape can be dominated by either abiotic and biotic landform processes. These two trajectories are distinctly different and are associated with their own unique linkages, feedbacks, and dynamics of abiotic and biotic land surface properties, producing a highly diverse desert landscape.

  17. Hormone balance and abiotic stress tolerance in crop plants.

    PubMed

    Peleg, Zvi; Blumwald, Eduardo

    2011-06-01

    Plant hormones play central roles in the ability of plants to adapt to changing environments, by mediating growth, development, nutrient allocation, and source/sink transitions. Although ABA is the most studied stress-responsive hormone, the role of cytokinins, brassinosteroids, and auxins during environmental stress is emerging. Recent evidence indicated that plant hormones are involved in multiple processes. Cross-talk between the different plant hormones results in synergetic or antagonic interactions that play crucial roles in response of plants to abiotic stress. The characterization of the molecular mechanisms regulating hormone synthesis, signaling, and action are facilitating the modification of hormone biosynthetic pathways for the generation of transgenic crop plants with enhanced abiotic stress tolerance.

  18. An abiotic analogue of the nuclear pore complex hydrogel.

    PubMed

    Bird, Sean P; Baker, Lane A

    2011-09-12

    We describe an abiotic hydrogel that mimics selectivity of the nuclear pore complex. Copolymerization of peptide tetramers (phenylalanine-serine-phenylalanine-glycine, FSFG) with acrylamide results in hydrophobic interactions significant enough to allow the formation of freestanding hydrogel structures. Incorporation of FSFG motifs also renders the hydrogels selective. Selective binding of importins and nuclear transport receptor-cargo complexes is qualitatively demonstrated and compared with polyacrylamide, hydrogels prepared from a control peptide, and hydrogels prepared from the nuclear pore complex protein Nsp1. These abiotic hydrogels will enable further studies of the unique transport mechanisms of the nuclear pore complex and provide an interesting paradigm for the future development of synthetic platforms for separations and selective interfaces.

  19. Experiments on the abiotic amplification of optical activity

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.; Blair, N. E.; Dirbas, F. M.

    1981-01-01

    Experiments concerning the physical mechanisms for the abiotic generation and chemical mechanisms for the amplification of optical activity in biological compounds are reviewed. Attention is given to experiments involving the determination of the differential adsorption of racemic amino acids on d- and l-quartz, the asymmetric photolysis of racemic amino acids by circularly polarized light, and the asymmetric radiolysis of solid amino acids by longitudinally polarized electrons, and the enantiomeric enrichments thus obtained are noted. Further experiments on the amplification of the chirality in the polymerization of D, L-amino acid mixtures and the hydrolysis of D-, L-, and D, L-polypeptides are discussed. It is suggested that a repetitive cycle of partial polymerization-hydrolyses may account for the abiotic genesis of optically enriched polypeptides on the primitive earth.

  20. Arbuscular mycorrhizal fungal responses to abiotic stresses: A review.

    PubMed

    Lenoir, Ingrid; Fontaine, Joël; Lounès-Hadj Sahraoui, Anissa

    2016-03-01

    The majority of plants live in close collaboration with a diversity of soil organisms among which arbuscular mycorrhizal fungi (AMF) play an essential role. Mycorrhizal symbioses contribute to plant growth and plant protection against various environmental stresses. Whereas the resistance mechanisms induced in mycorrhizal plants after exposure to abiotic stresses, such as drought, salinity and pollution, are well documented, the knowledge about the stress tolerance mechanisms implemented by the AMF themselves is limited. This review provides an overview of the impacts of various abiotic stresses (pollution, salinity, drought, extreme temperatures, CO2, calcareous, acidity) on biodiversity, abundance and development of AMF and examines the morphological, biochemical and molecular mechanisms implemented by AMF to survive in the presence of these stresses.

  1. Sustainability of Long-Term Abiotic Attenuation of Chlorinated Ethenes

    DTIC Science & Technology

    2007-09-28

    that contribute to abiotic transformations is critical to assess the feasibility of natural attenuation and promote the rationale design of...anaerobic glovebox. The resulting slurry was mixed for three days and then decanted into polypropylene centrifuge bottles. These bottles were...tightly sealed and centrifuged at 8000 rpm for 10 minutes. The supernatant in the bottles was discarded, and fresh nitrogen-purged deionized water was

  2. Biotic-Abiotic Nanoscale Interactions in Biological Fuel Cells

    DTIC Science & Technology

    2014-03-28

    Force Office of Scientific Research 875 North Randolph Street 4027 Arlington VA 22203 email: Patrick.Bradshaw@afosr.af.mil phone : 703-588-8492...Science Center 215C Los Angeles, CA 90089-0484 email: mnaggar@usc.edu phone : 213-740-2394 2 Biotic-Abiotic Nanoscale Interactions in...aggregation – collaboration with Naval Research Lab. 2.4 As part of an international collaboration, we reported on filamentous bacteria mediating centimeter

  3. Wheat EST resources for functional genomics of abiotic stress

    PubMed Central

    Houde, Mario; Belcaid, Mahdi; Ouellet, François; Danyluk, Jean; Monroy, Antonio F; Dryanova, Ani; Gulick, Patrick; Bergeron, Anne; Laroche, André; Links, Matthew G; MacCarthy, Luke; Crosby, William L; Sarhan, Fathey

    2006-01-01

    Background Wheat is an excellent species to study freezing tolerance and other abiotic stresses. However, the sequence of the wheat genome has not been completely characterized due to its complexity and large size. To circumvent this obstacle and identify genes involved in cold acclimation and associated stresses, a large scale EST sequencing approach was undertaken by the Functional Genomics of Abiotic Stress (FGAS) project. Results We generated 73,521 quality-filtered ESTs from eleven cDNA libraries constructed from wheat plants exposed to various abiotic stresses and at different developmental stages. In addition, 196,041 ESTs for which tracefiles were available from the National Science Foundation wheat EST sequencing program and DuPont were also quality-filtered and used in the analysis. Clustering of the combined ESTs with d2_cluster and TGICL yielded a few large clusters containing several thousand ESTs that were refractory to routine clustering techniques. To resolve this problem, the sequence proximity and "bridges" were identified by an e-value distance graph to manually break clusters into smaller groups. Assembly of the resolved ESTs generated a 75,488 unique sequence set (31,580 contigs and 43,908 singletons/singlets). Digital expression analyses indicated that the FGAS dataset is enriched in stress-regulated genes compared to the other public datasets. Over 43% of the unique sequence set was annotated and classified into functional categories according to Gene Ontology. Conclusion We have annotated 29,556 different sequences, an almost 5-fold increase in annotated sequences compared to the available wheat public databases. Digital expression analysis combined with gene annotation helped in the identification of several pathways associated with abiotic stress. The genomic resources and knowledge developed by this project will contribute to a better understanding of the different mechanisms that govern stress tolerance in wheat and other cereals. PMID

  4. Titania may produce abiotic oxygen atmospheres on habitable exoplanets

    NASA Astrophysics Data System (ADS)

    Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

    2015-12-01

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets.Reference:Narita N. et al.,Scientific Reports 5, Article number: 13977 (2015)http://www.nature.com/articles/srep13977

  5. Titania may produce abiotic oxygen atmospheres on habitable exoplanets.

    PubMed

    Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

    2015-09-10

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets.

  6. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths.

    PubMed

    Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y; Kunoh, Hitoshi; Takada, Jun

    2016-06-03

    Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths.

  7. Abiotic carbonate dissolution traps carbon in a semiarid desert

    PubMed Central

    Fa, Keyu; Liu, Zhen; Zhang, Yuqing; Qin, Shugao; Wu, Bin; Liu, Jiabin

    2016-01-01

    It is generally considered that desert ecosystems release CO2 to the atmosphere, but recent studies in drylands have shown that the soil can absorb CO2 abiotically. However, the mechanisms and exact location of abiotic carbon absorption remain unclear. Here, we used soil sterilization, 13CO2 addition, and detection methods to trace 13C in the soil of the Mu Us Desert, northern China. After 13CO2 addition, a large amount of 13CO2 was absorbed by the sterilised soil, and 13C was found enriched both in the soil gaseous phase and dissolved inorganic carbon (DIC). Further analysis indicated that about 79.45% of the total 13C absorbed by the soil was trapped in DIC, while the amount of 13C in the soil gaseous phase accounted for only 0.22% of the total absorbed 13C. However, about 20.33% of the total absorbed 13C remained undetected. Our results suggest that carbonate dissolution might occur predominately, and the soil liquid phase might trap the majority of abiotically absorbed carbon. It is possible that the trapped carbon in the soil liquid phase leaches into the groundwater; however, further studies are required to support this hypothesis. PMID:27020762

  8. Titania may produce abiotic oxygen atmospheres on habitable exoplanets

    PubMed Central

    Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

    2015-01-01

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets. PMID:26354078

  9. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

    PubMed Central

    Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

    2016-01-01

    Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677

  10. Abscisic Acid and Abiotic Stress Tolerance in Crop Plants

    PubMed Central

    Sah, Saroj K.; Reddy, Kambham R.; Li, Jiaxu

    2016-01-01

    Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression. PMID:27200044

  11. Resistance Responses of Potato to Vesicular-Arbuscular Mycorrhizal Fungi under Varying Abiotic Phosphorus Levels.

    PubMed

    McArthur, D A; Knowles, N R

    1992-09-01

    In mycorrhizal symbioses, susceptibility of a host plant to infection by fungi is influenced by environmental factors, especially the availability of soil phosphorus. This study describes morphological and biochemical details of interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus and potato (Solanum tuberosum L. cv Russet Burbank) plants, with a particular focus on the physiological basis for P-induced resistance of roots to infection. Root infection by the VAM fungus Glomus fasciculatum ([Thaxt. sensu Gerdemann] Gerdemann and Trappe) was extensive for plants grown with low abiotic P supply, and plant biomass accumulation was enhanced by the symbiosis. The capacity of excised roots from P-deficient plants to produce ethylene in the presence or absence of exogenous 1-amino cyclopropane-1-carboxylic acid (ACC) was markedly reduced by VAM infection. This apparent inhibition of ACC oxidase (ACC(ox)) activity was localized to areas containing infected roots, as demonstrated in split-root studies. Furthermore, leachate from VAM roots contained a potent water-soluble inhibitor of ethylene generation from exogenous ACC by nonmycorrhizal (NM) roots. The leachate from VAM-infected roots had a higher concentration of phenolics, relative to that from NM roots. Moreover, the rates of ethylene formation and phenolic concentration in leachates from VAM roots were inversely correlated, suggesting that this inhibitor may be of a phenolic nature. The specific activity of extracellular peroxidase recovered in root leachates was not stimulated by VAM infection, although activity on a fresh weight basis was significantly enhanced, reflecting the fact that VAM roots had higher protein content than NM roots. Polyphenol oxidase activity of roots did not differ between NM and VAM roots. These results characterize the low resistance response of P-deficient plants to VAM infection. When plants were grown with higher abiotic P supply, the relative benefit of the VAM symbiosis

  12. Identification and expression analysis of WRKY family genes under biotic and abiotic stresses in Brassica rapa.

    PubMed

    Kayum, Md Abdul; Jung, Hee-Jeong; Park, Jong-In; Ahmed, Nasar Uddin; Saha, Gopal; Yang, Tae-Jin; Nou, Ill-Sup

    2015-02-01

    WRKY proteins constitute one of the largest transcription factor families in higher plants, and they are involved in multiple biological processes such as plant development, metabolism, and responses to biotic and abiotic stresses. Genes of this family have been well documented in response to many abiotic and biotic stresses in many plant species, but not yet against Pectobacterium carotovorum subsp. carotovorum and Fusarium oxysporum f.sp. conglutinans in any of the plants. Moreover, potentiality of a specific gene may vary depending on stress conditions and genotypes. To identify stress resistance-related potential WRKY genes of Brassica rapa, we analyzed their expressions against above-mentioned pathogens and cold, salt, and drought stresses in B. rapa. Stress resistance-related functions of all Brassica rapa WRKY (BrWRKY) genes were firstly analyzed through homology study with existing biotic and abiotic stress resistance-related WRKY genes of other plant species and found a high degree of homology. We then identified all BrWRKY genes in a Br135K microarray dataset, which was created by applying low-temperature stresses to two contrasting Chinese cabbage doubled haploid (DH) lines, Chiifu and Kenshin, and selected 41 BrWRKY genes with high and differential transcript abundance levels. These selected genes were further investigated under cold, salt, and drought stresses as well as after infection with P. carotovorum subsp. carotovorum and F. oxysporum f.sp. conglutinans in B. rapa. The selected genes showed an organ-specific expression, and 22 BrWRKY genes were differentially expressed in Chiifu compared to Kenshin under cold and drought stresses. Six BrWRKY genes were more responsive in Kenshin compared to Chiffu under salt stress. In addition, eight BrWRKY genes showed differential expression after P. carotovorum subsp. carotovorum infection and five genes after F. oxysporum f.sp. conglutinans infection in B. rapa. Thus, the differentially expressed Br

  13. Exploration of Genetic and Genomic Resources for Abiotic and Biotic Stress Tolerance in Pearl Millet

    PubMed Central

    Shivhare, Radha; Lata, Charu

    2017-01-01

    Pearl millet is one of the most important small-grained C4 Panicoid crops with a large genome size (∼2352 Mb), short life cycle and outbreeding nature. It is highly resilient to areas with scanty rain and high temperature. Pearl millet is a nutritionally superior staple crop for people inhabiting hot, drought-prone arid and semi-arid regions of South Asia and Africa where it is widely grown and used for food, hay, silage, bird feed, building material, and fuel. Having excellent nutrient composition and exceptional buffering capacity against variable climatic conditions and pathogen attack makes pearl millet a wonderful model crop for stress tolerance studies. Pearl millet germplasm show a large range of genotypic and phenotypic variations including tolerance to abiotic and biotic stresses. Conventional breeding for enhancing abiotic and biotic stress resistance in pearl millet have met with considerable success, however, in last few years various novel approaches including functional genomics and molecular breeding have been attempted in this crop for augmenting yield under adverse environmental conditions, and there is still a lot of scope for further improvement using genomic tools. Discovery and use of various DNA-based markers such as EST-SSRs, DArT, CISP, and SSCP-SNP in pearl millet not only help in determining population structure and genetic diversity but also prove to be important for developing strategies for crop improvement at a faster rate and greater precision. Molecular marker-based genetic linkage maps and identification of genomic regions determining yield under abiotic stresses particularly terminal drought have paved way for marker-assisted selection and breeding of pearl millet cultivars. Reference collections and marker-assisted backcrossing have also been used to improve biotic stress resistance in pearl millet specifically to downy mildew. Whole genome sequencing of pearl millet genome will give new insights for processing of functional

  14. Abiotic controls on H{sub 2} production from basalt-water reactions and implications for aquifer biogeochemistry

    SciTech Connect

    Stevens, T.O.; McKinley, J.P.

    2000-03-01

    Abiotic production of H{sub 2} from basalt reactions in aqueous solutions is hypothesized to support microbial ecosystems in deep subsurface aquifers, such as those found in the Columbia River Basalt group (CRB). The authors investigated factors controlling this phenomenon, including rock composition, pH, temperature, sterilization method, reducing agents, and product removal. Ferrous silicate minerals were found to be the basalt components responsible for H{sub 2} production from anaerobic water-rock interactions. H{sub 2} evolution was faster at pH < 7 but occurred from pH 5 to pH 11, which covers the pH range (7--10) measured in CRB groundwaters. The onset of H{sub 2} evolution coincided with the appearance of dissolved Fe{sup 2+}, and an apparent alkaline inhibition could be alleviated by the addition of excess FeCl{sub 2}. This may reflect, in part, the low redox conditions needed for H{sub 2} evolution and suggests that H{sub 2} may be controlled by reaction rates of ferrous silicate minerals. Rates were higher at 60 C than at 30 C, suggesting that the geothermal gradient may lead to increased H{sub 2} production at depth. The results were consistent with the hypothesis at depth. The results were consistent with the hypothesis that basalt-redox reactions support primary production by microorganisms in some terrestrial subsurface environments.

  15. Factors associated with early adoption of the HPV vaccine in US male adolescents include Hispanic ethnicity and receipt of other vaccines.

    PubMed

    Kepka, Deanna; Ding, Qian; Hawkins, Amy J; Warner, Echo L; Boucher, Kenneth M

    2016-12-01

    Adolescent males' HPV vaccine initiation and completion in the United States is far below the Healthy People 2020 goal of 80% 3-dose completion among boys. In 2012, less than 7% of males ages 13-17 years had completed the 3-dose series. The Diffusion of Innovations framework guided this investigation of factors related to early adoption of HPV vaccination among male adolescents. Provider-validated data from the 2012 National Immunization Survey-Teen (NIS-Teen) for male adolescents ages 13-17 years were analyzed via a multivariable Poisson regression to estimate prevalence ratios for factors associated with HPV vaccine initiation and completion. Adolescent males who are Hispanic and those who are up to date on other recommended adolescent vaccinations were most likely to complete the HPV vaccine. Public health interventions are needed to improve low HPV vaccination rates among adolescent males in the United States. Description of early adopters of the HPV vaccine provides historical context of HPV vaccination acceptance that is needed to inform the design of targeted vaccination interventions to prevent negative HPV-associated outcomes.

  16. The yeast BDF1 gene encodes a transcription factor involved in the expression of a broad class of genes including snRNAs.

    PubMed Central

    Lygerou, Z; Conesa, C; Lesage, P; Swanson, R N; Ruet, A; Carlson, M; Sentenac, A; Séraphin, B

    1994-01-01

    While screening for genes that affect the synthesis of yeast snRNPs, we identified a thermosensitive mutant that abolishes the production of a reporter snRNA at the non-permissive temperature. This mutant defines a new gene, named BDF1. In a bdf1-1 strain, the reporter snRNA synthesized before the temperature shift remains stable at the non-permissive temperature. This demonstrates that the BDF1 gene affects the synthesis rather than the stability of the reporter snRNA and suggests that the BDF1 gene encodes a transcription factor. BDF1 is present in single copy on yeast chromosome XII, and is important for normal vegetative growth but not essential for cell viability. bdf1 null mutants share common phenotypes with several mutants affecting general transcription and are defective in snRNA production. BDF1 encodes a protein of 687 amino-acids containing two copies of the bromodomain, a motif also present in other transcription factors as well as a new conserved domain, the ET domain, also present in Drosophila and human proteins. Images PMID:7816623

  17. ATHB17 enhances stress tolerance by coordinating photosynthesis associated nuclear gene and ATSIG5 expression in response to abiotic stress

    PubMed Central

    Zhao, Ping; Cui, Rong; Xu, Ping; Wu, Jie; Mao, Jie-Li; Chen, Yu; Zhou, Cong-Zhao; Yu, Lin-Hui; Xiang, Cheng-Bin

    2017-01-01

    Photosynthesis is sensitive to environmental stress and must be efficiently modulated in response to abiotic stress. However, the underlying mechanisms are not well understood. Here we report that ARABIDOPSIS THALIANA HOMEOBOX 17 (ATHB17), an Arabidopsis HD-Zip transcription factor, regulated the expression of a number of photosynthesis associated nuclear genes (PhANGs) involved in the light reaction and ATSIG5 in response to abiotic stress. ATHB17 was responsive to ABA and multiple stress treatments. ATHB17-overexpressing plants displayed enhanced stress tolerance, whereas its knockout mutant was more sensitive compared to the wild type. Through RNA-seq and quantitative real-time reverse transcription PCR (qRT-PCR) analysis, we found that ATHB17 did not affect the expression of many known stress-responsive marker genes. Interestingly, we found that ATHB17 down-regulated many PhANGs and could directly modulate the expression of several PhANGs by binding to their promoters. Moreover, we identified ATSIG5, encoding a plastid sigma factor, as one of the target genes of ATHB17. Loss of ATSIG5 reduced salt tolerance while overexpression of ATSIG5 enhanced salt tolerance, similar to that of ATHB17. ATHB17 can positively modulate the expression of many plastid encoded genes (PEGs) through regulation of ATSIG5. Taken together, our results suggest that ATHB17 may play an important role in protecting plants by adjusting expression of PhANGs and PEGs in response to abiotic stresses. PMID:28358040

  18. Iron-mediated microbial oxidation and abiotic reduction of organic contaminants under anoxic conditions.

    PubMed

    Tobler, Nicole B; Hofstetter, Thomas B; Straub, Kristina L; Fontana, Daniela; Schwarzenbach, René P

    2007-11-15

    In anoxic environments, the oxidation of organic compounds, such as BTEX fuel components, by dissimilatory Fe(III) reduction can generate reactive mineral-bound Fe(II) species, which in turn are able to reduce other classes of organic and inorganic groundwater contaminants. In this study, we designed and evaluated an anaerobic batch reactor that mimicks iron-reducing conditions to investigate the factors that favor the coupling of microbial toluene oxidation and abiotic reduction of nitroaromatic contaminants. We investigated the influence of different Fe(III)-bearing minerals and combinations thereof on the coupling of these two processes. Results from laboratory model systems show that complete oxidation of toluene to CO2 by Geobacter metallireducens in the presence of Fe(III)-bearing minerals leads to the formation of mineral-bound Fe(II) species capable of the reduction of 4-nitroacetophenone. Whereas significant microbial toluene oxidation was only observed in the presence of amorphous Fe(III) phases, reduction of nitroaromatic compounds only proceeded with Fe(II) species bound to crystalline Fe(III) oxides. Our results suggest that in anoxic soils and sediments containing amorphous and crystalline iron phases simultaneously, coupling of microbial oxidation and abiotic reduction of organic compounds may allow for concurrent natural attenuation of different contaminant classes.

  19. Using Phenomic Analysis of Photosynthetic Function for Abiotic Stress Response Gene Discovery

    PubMed Central

    Rungrat, Tepsuda; Awlia, Mariam; Brown, Tim; Cheng, Riyan; Sirault, Xavier; Fajkus, Jiri; Trtilek, Martin; Furbank, Bob; Badger, Murray; Tester, Mark; Pogson, Barry J; Borevitz, Justin O; Wilson, Pip

    2016-01-01

    Monitoring the photosynthetic performance of plants is a major key to understanding how plants adapt to their growth conditions. Stress tolerance traits have a high genetic complexity as plants are constantly, and unavoidably, exposed to numerous stress factors, which limits their growth rates in the natural environment. Arabidopsis thaliana, with its broad genetic diversity and wide climatic range, has been shown to successfully adapt to stressful conditions to ensure the completion of its life cycle. As a result, A. thaliana has become a robust and renowned plant model system for studying natural variation and conducting gene discovery studies. Genome wide association studies (GWAS) in restructured populations combining natural and recombinant lines is a particularly effective way to identify the genetic basis of complex traits. As most abiotic stresses affect photosynthetic activity, chlorophyll fluorescence measurements are a potential phenotyping technique for monitoring plant performance under stress conditions. This review focuses on the use of chlorophyll fluorescence as a tool to study genetic variation underlying the stress tolerance responses to abiotic stress in A. thaliana. PMID:27695390

  20. Silicon: a duo synergy for regulating crop growth and hormonal signaling under abiotic stress conditions.

    PubMed

    Kim, Yoon-Ha; Khan, Abdul Latif; Lee, In-Jung

    2016-12-01

    Abiotic stresses, such as salinity, heavy metals and drought, are some of the most devastating factors hindering sustainable crop production today. Plants use their own defensive strategies to cope with the adverse effects of these stresses, via the regulation of the expression of essential phytohormones, such as gibberellins (GA), salicylic acid (SA), jasmonates (JA), abscisic acid (ABA) and ethylene (ET). However, the efficacy of the endogenous defensive arsenals of plants often falls short if the stress persists over an extended period. Various strategies are developed to improve stress tolerance in plants. For example, silicon (Si) is widely considered to possess significant potential as a substance which ameliorate the negative effects of abiotic stresses, and improves plant growth and biomass accumulation. This review aims to explain how Si application influences the signaling of the endogenous hormones GA, SA, ABA, JA and ET during salinity, wounding, drought and metal stresses in crop plants. Phytohormonal cross talk plays an important role in the regulation of induced defences against stress. However, detailed molecular and proteomic research into these interactions is needed in order to identify the underlying mechanisms of stress tolerance that is imparted by Si application and uptake.

  1. Abiotic autumnal organic matter deposition and grazing disturbance effects on epilithic biofilm succession.

    PubMed

    Lang, Jennifer M; McEwan, Ryan W; Benbow, M Eric

    2015-06-01

    Stream epilithic biofilm community assembly is influenced in part by environmental factors. Autumn leaf deposition is an annual resource subsidy to streams, but the physical effects of leaves settling on epilithic biofilms has not been investigated.We hypothesized that bacterial and microeukaryotic community assembly would follow a successional sequence that was mediated by abiotic effects that were simulating leaf deposition (reduced light and flow) and by biotic (snail grazing)disturbance. This hypothesis was tested using an in situ experimental manipulation. Ambient biofilms had greater algal biomass and distinct ARISA community profiles compared to biofilms developed under manipulated conditions. There were no significant differences in biofilm characteristics associated with grazing, suggesting that results were driven by reduced light/flow rather than invertebrate disturbance; however, grazing appeared to increase bacterial taxon richness.Interestingly at day 38, all treatments grouped together in ordination space and had similar algal/total biomass ratios. We suggest that algal priming promoted a shift in ambient biofilms but that this effect is dependent upon successional timing of algal establishment. These data demonstrate that abiotic effects were more influential than local grazing disturbance and imply that leaf litter deposition may have bottom-up effects on the stream ecosystem through altered epilithic biofilms.

  2. Abiotic influences on the biomass of Vallisneria americana Michx. In the Upper Mississippi River

    USGS Publications Warehouse

    Kreiling, Rebecca M.; Yin, Y.; Gerber, D.T.

    2007-01-01

    American wildcelery, Vallisneria americana Michx. is an ecologically important component of aquatic communities in the Upper Mississippi River (UMR). We conducted a study in 2002 to determine the association of several abiotic factors on the vegetative growth of Vallisneria in Navigation Pool 8 (Pool 8) of the UMR. We measured turbidity, percent light absorbance, surface water ammonium, surface water nitrate, current velocity, conductivity, pH and water depth throughout one growing season at 56 stratified sites based on where Vallisneria occurred in previous years. Sediment and aboveground biomass samples were collected during peak growth. Sediment was analysed for organic content, particle size, pore water nitrate and pore water ammonium. Vallisneria biomass samples were dried to constant mass. Because some sites were without water for much of the growing season, only data from 52 sites were reported. Biomass was associated with depth, percent light absorbance, turbidity and wind fetch. Vallisneria was abundant in the depth range of 0.55 to 1.03 m, in areas receiving at least 38% of surface light and in areas exposed to greater wind fetch (>2000 m). Our results suggest that the primary abiotic variable associated with Vallisneria americana in the UMR is light, not nutrients.

  3. Cyclone Tolerance in New World Arecaceae: Biogeographic Variation and Abiotic Natural Selection

    PubMed Central

    Griffith, M. Patrick; Noblick, Larry R.; Dowe, John L.; Husby, Chad E.; Calonje, Michael A.

    2008-01-01

    Background and Aims Consistent abiotic factors can affect directional selection; cyclones are abiotic phenomena with near-discrete geographic limits. The current study investigates selective pressure of cyclones on plants at the species level, testing for possible natural selection. Methods New World Arecaceae (palms) are used as a model system, as plants with monopodial, unbranched arborescent form are most directly affected by the selective pressure of wind load. Living specimens of known provenance grown at a common site were affected by the same cyclone. Data on percentage mortality were compiled and analysed in biogeographic and phylogenetic contexts. Key Results Palms of cyclone-prone provenance exhibited a much lower (one order of magnitude) range in cyclone tolerance, and significantly lower (P < 0·001) mean percentage mortality than collections from cyclone-free areas. Palms of cyclone-free provenance had much greater variation in tolerance, and significantly greater mean percentage mortality. A test for serial independence recovered no significant phylogenetic autocorrelation of percentage mortality. Conclusions Variation in cyclone tolerance in New World Arecaceae correlates with biogeography, and is not confounded with phylogeny. These results suggest natural selection of cyclone tolerance in cyclone-prone areas. PMID:18669575

  4. Biotic and abiotic effects on CO2 sequestration during microbially-induced calcium carbonate precipitation.

    PubMed

    Okyay, Tugba Onal; Rodrigues, Debora F

    2015-03-01

    In this study, CO2 sequestration was investigated through the microbially-induced calcium carbonate precipitation (MICP) process with isolates obtained from a cave called 'Cave Without A Name' (Boerne, TX, USA) and the Pamukkale travertines (Denizli, Turkey). The majority of the bacterial isolates obtained from these habitats belonged to the genera Sporosarcina, Brevundimonas, Sphingobacterium and Acinetobacter. The isolates were investigated for their capability to precipitate calcium carbonate and sequester CO2. Biotic and abiotic effects of CO2 sequestration during MICP were also investigated. In the biotic effect, we observed that the rate and concentration of CO2 sequestered was dependent on the species or strains. The main abiotic factors affecting CO2 sequestration during MICP were the pH and medium components. The increase in pH led to enhanced CO2 sequestration by the growth medium. The growth medium components, on the other hand, were shown to affect both the urease activity and CO2 sequestration. Through the Plackett-Burman experimental design, the most important growth medium component involved in CO2 sequestration was determined to be urea. The optimized medium composition by the Plackett-Burman design for each isolate led to a statistically significant increase, of up to 148.9%, in CO2 uptake through calcification mechanisms.

  5. Expression Pattern of ERF Gene Family under Multiple Abiotic Stresses in Populus simonii × P. nigra.

    PubMed

    Yao, Wenjing; Zhang, Xuemei; Zhou, Boru; Zhao, Kai; Li, Renhua; Jiang, Tingbo

    2017-01-01

    Identification of gene expression patterns of key genes across multiple abiotic stresses is critical for mechanistic understanding of stress resistance in plant. In the present study, we identified differentially expressed genes (DEGs) in di-haploid Populus simonii × P. nigra under respective stresses of NaCl, KCl, CdCl2, and PEG. On the basis of RNA-Seq, we detected 247 DEGs that are shared by the four stresses in wild type poplar, and mRNA abundance of the DEGs were validated in transgenic poplar overexpressing ERF76 gene by RNA-Seq and RT-qPCR. Results from gene ontology analysis indicated that these genes are enriched in significant pathways, such as phenylpropanoid biosynthesis, phenylalanine metabolism, starch and sucrose metabolism, and plant hormone signal transduction. Ethylene response factor (ERF) gene family plays significant role in plant abiotic stress responses. We also investigated expression pattern of ERF gene family under the four stresses. The ERFs and DEGs share similar expression pattern across the four stresses. The transgenic poplar is superior to WT in morphologic, physiological and biochemical traits, which demonstrated the ERF76 gene plays a significant role in stress resistance. These studies will give a rise in understanding the stress response mechanisms in poplar.

  6. Expression Pattern of ERF Gene Family under Multiple Abiotic Stresses in Populus simonii × P. nigra

    PubMed Central

    Yao, Wenjing; Zhang, Xuemei; Zhou, Boru; Zhao, Kai; Li, Renhua; Jiang, Tingbo

    2017-01-01

    Identification of gene expression patterns of key genes across multiple abiotic stresses is critical for mechanistic understanding of stress resistance in plant. In the present study, we identified differentially expressed genes (DEGs) in di-haploid Populus simonii × P. nigra under respective stresses of NaCl, KCl, CdCl2, and PEG. On the basis of RNA-Seq, we detected 247 DEGs that are shared by the four stresses in wild type poplar, and mRNA abundance of the DEGs were validated in transgenic poplar overexpressing ERF76 gene by RNA-Seq and RT-qPCR. Results from gene ontology analysis indicated that these genes are enriched in significant pathways, such as phenylpropanoid biosynthesis, phenylalanine metabolism, starch and sucrose metabolism, and plant hormone signal transduction. Ethylene response factor (ERF) gene family plays significant role in plant abiotic stress responses. We also investigated expression pattern of ERF gene family under the four stresses. The ERFs and DEGs share similar expression pattern across the four stresses. The transgenic poplar is superior to WT in morphologic, physiological and biochemical traits, which demonstrated the ERF76 gene plays a significant role in stress resistance. These studies will give a rise in understanding the stress response mechanisms in poplar. PMID:28265277

  7. Life without water: cross-resistance of anhydrobiotic cell line to abiotic stresses

    NASA Astrophysics Data System (ADS)

    Gusev, Oleg

    2016-07-01

    Anhydrobiosis is an intriguing phenomenon of natural ability of some organisms to resist water loss. The larvae of Polypedilum vanderplanki, the sleeping chironomid is the largest and most complex anhydrobionts known to date. The larvae showed ability to survive variety of abiotic stresses, including outer space environment. Recently cell line (Pv11) derived from the embryonic mass of the chironomid was established. Initially sensitive to desiccation cells, are capable to "induced" anhydrobiosis, when the resistance to desiccation can be developed by pre-treatment of the cells with trehalose followed by quick desiccation. We have further conducted complex analysis of the whole genome transcription response of Pv11 cells to different abiotic stresses, including oxidative stress and irradiation. Comparative analysis showed that the gene set, responsible for formation of desiccation resistance (ARID regions in the genome) is also activated in response to other types of stresses and likely to contribute to general enhancing of the resistance of the cells to harsh environment. We have further demonstrated that the cells are able to protect recombinant proteins from harmful effect of desiccation

  8. A database of annotated tentative orthologs from crop abiotic stress transcripts.

    PubMed

    Balaji, Jayashree; Crouch, Jonathan H; Petite, Prasad V N S; Hoisington, David A

    2006-10-07

    A minimal requirement to initiate a comparative genomics study on plant responses to abiotic stresses is a dataset of orthologous sequences. The availability of a large amount of sequence information, including those derived from stress cDNA libraries allow for the identification of stress related genes and orthologs associated with the stress response. Orthologous sequences serve as tools to explore genes and their relationships across species. For this purpose, ESTs from stress cDNA libraries across 16 crop species including 6 important cereal crops and 10 dicots were systematically collated and subjected to bioinformatics analysis such as clustering, grouping of tentative orthologous sets, identification of protein motifs/patterns in the predicted protein sequence, and annotation with stress conditions, tissue/library source and putative function. All data are available to the scientific community at http://intranet.icrisat.org/gt1/tog/homepage.htm. We believe that the availability of annotated plant abiotic stress ortholog sets will be a valuable resource for researchers studying the biology of environmental stresses in plant systems, molecular evolution and genomics.

  9. An Analysis of Factor Extraction Strategies: A Comparison of the Relative Strengths of Principal Axis, Ordinary Least Squares, and Maximum Likelihood in Research Contexts That Include Both Categorical and Continuous Variables

    ERIC Educational Resources Information Center

    Coughlin, Kevin B.

    2013-01-01

    This study is intended to provide researchers with empirically derived guidelines for conducting factor analytic studies in research contexts that include dichotomous and continuous levels of measurement. This study is based on the hypotheses that ordinary least squares (OLS) factor analysis will yield more accurate parameter estimates than…

  10. Response to Therapy and Outcomes in Oropharyngeal Cancer Are Associated With Biomarkers Including Human Papillomavirus, Epidermal Growth Factor Receptor, Gender, and Smoking

    SciTech Connect

    Kumar, Bhavna; Cordell, Kitrina G.; Lee, Julia S.; Prince, Mark E.; Tran, Huong H.; Wolf, Gregory T.; Urba, Susan G.; Worden, Francis P.; Chepeha, Douglas B.; Teknos, Theodoros N.; Eisbruch, Avraham; Tsien, Christina I.; Taylor, Jeremy; D'Silva, Nisha J.; Yang, Kun; Kurnit, David M.; Bradford, Carol R.

    2007-10-01

    Induction chemotherapy and concurrent chemoradiation for responders or immediate surgery for non-responders is an effective treatment strategy head and neck squamous cell carcinoma (HNSCC) of the larynx and oropharynx. Biomarkers that predict outcome would be valuable in selecting patients for therapy. In this study, the presence and titer of high risk human papilloma virus (HPV) and expression of epidermal growth factor receptor (EGFR) in pre-treatment biopsies, as well as smoking and gender were examined in oropharynx cancer patients enrolled in an organ sparing trial. HPV16 copy number was positively associated with response to therapy and with overall and disease specific survival, whereas EGFR expression, current or former smoking behavior, and female gender (in this cohort) were associated with poor response and poor survival in multivariate analysis. Smoking cessation and strategies to target EGFR may be useful adjuncts for therapy to improve outcome in the cases with the poorest biomarker profile.

  11. Modifiable risk factors including sunlight exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau.

    PubMed

    Ke, Liang; Ho, Jacky; Feng, Jianzhang; Mpofu, Elias; Dibley, Michael J; Feng, Xiuhua; Van, Florance