Elucidating the Genetic and Molecular Mechanisms Underlying Thermal Tolerance in Embryonic Drosophila Melanogaster PDF Download
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Author: Kylie Maureen Finnegan
Publisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 0
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Book Description
Rapidly changing climate conditions, including extreme temperature events, have wide-reaching implications for organismal adaptation. Organisms with complex life cycles can be differentially susceptible to physiological challenges posed by acute temperature stressors depending on developmental stage. Thus, sensitive life stages may act as a selective sieve through which species are differentially able to persist in a changing, warming world. Terrestrial ectotherms, such as the cosmopolitan Drosophila melanogaster, are dependent upon their external environment to dictate internal body temperature. The non-motile D. melanogaster embryo is entirely reliant upon innate physiological defense mechanisms to protect against and respond to the damaging effects of heat stress, given the inability to behaviorally thermoregulate. Early embryos (0-2 hours post fertilization) have been shown to display substantial differences in thermal tolerance between regionally distinct tropical and temperate populations. The rapid local adaptation seen in this trait is indicative of strong selection for the underlying favorable alleles. However, the underlying genetic basis of embryonic thermal tolerance is previously unknown. Previously, our lab used whole genome quantitative trait locus (QTL) mapping via a repeated backcrossing design to identify the genomic basis of differential embryonic thermal tolerance between flies of tropical vs. temperate origin. To determine the extent to which gene regulatory variation underlies embryonic thermal tolerance, I measured transcriptomic responses to heat stress using the same tropical, temperate, and advanced introgression lines that were used in the QTL mapping study. I identify 212 differentially expressed genes between the three genotypes (tropical, temperate, introgression) and 650 differently expressed genes between the two temperature treatments (25°C, 34°C). Additionally, I identify gene clusters containing a total of 985 genes that were significantly associated with response to heat stress, and one gene cluster containing a total of 52 genes that were significantly associated with LT50. Functional analysis of these differentially expressed genes and clusters indicates that precise regulation of aerobic metabolism and oxidative phosphorylation is instrumental in reducing cellular damage accrued due to the formation of reactive oxygen species (ROS) by downregulating processes that lead to ROS formation. I observe a strongly conserved heat shock response to the stressful treatment temperature amongst all genotypes, including upregulation of protective elements and some metabolic downregulation. The most prominent finding, supported by the list of genes containing polymorphisms in different allelic frequencies between temperate and introgression genotypes, was the difference in magnitude and depth of the downregulation of metabolic systems in more thermally tolerant embryos. In addition to reduction of catabolic activity, more nuanced regulation of transcriptional machinery and the formation subcellular nucleoprotein complexes appear to be plastic mechanisms contributing to the divergence in thermal tolerance between locally adapted regional genotypes.
Author: Kylie Maureen Finnegan
Publisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 0
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Book Description
Rapidly changing climate conditions, including extreme temperature events, have wide-reaching implications for organismal adaptation. Organisms with complex life cycles can be differentially susceptible to physiological challenges posed by acute temperature stressors depending on developmental stage. Thus, sensitive life stages may act as a selective sieve through which species are differentially able to persist in a changing, warming world. Terrestrial ectotherms, such as the cosmopolitan Drosophila melanogaster, are dependent upon their external environment to dictate internal body temperature. The non-motile D. melanogaster embryo is entirely reliant upon innate physiological defense mechanisms to protect against and respond to the damaging effects of heat stress, given the inability to behaviorally thermoregulate. Early embryos (0-2 hours post fertilization) have been shown to display substantial differences in thermal tolerance between regionally distinct tropical and temperate populations. The rapid local adaptation seen in this trait is indicative of strong selection for the underlying favorable alleles. However, the underlying genetic basis of embryonic thermal tolerance is previously unknown. Previously, our lab used whole genome quantitative trait locus (QTL) mapping via a repeated backcrossing design to identify the genomic basis of differential embryonic thermal tolerance between flies of tropical vs. temperate origin. To determine the extent to which gene regulatory variation underlies embryonic thermal tolerance, I measured transcriptomic responses to heat stress using the same tropical, temperate, and advanced introgression lines that were used in the QTL mapping study. I identify 212 differentially expressed genes between the three genotypes (tropical, temperate, introgression) and 650 differently expressed genes between the two temperature treatments (25°C, 34°C). Additionally, I identify gene clusters containing a total of 985 genes that were significantly associated with response to heat stress, and one gene cluster containing a total of 52 genes that were significantly associated with LT50. Functional analysis of these differentially expressed genes and clusters indicates that precise regulation of aerobic metabolism and oxidative phosphorylation is instrumental in reducing cellular damage accrued due to the formation of reactive oxygen species (ROS) by downregulating processes that lead to ROS formation. I observe a strongly conserved heat shock response to the stressful treatment temperature amongst all genotypes, including upregulation of protective elements and some metabolic downregulation. The most prominent finding, supported by the list of genes containing polymorphisms in different allelic frequencies between temperate and introgression genotypes, was the difference in magnitude and depth of the downregulation of metabolic systems in more thermally tolerant embryos. In addition to reduction of catabolic activity, more nuanced regulation of transcriptional machinery and the formation subcellular nucleoprotein complexes appear to be plastic mechanisms contributing to the divergence in thermal tolerance between locally adapted regional genotypes.
Author: Fiona Elizabeth Cockerell
Publisher:
ISBN:
Category :
Languages : en
Pages : 298
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Book Description
Since heat stress affects most organisms it is important that we understand how adaptation occurs to increasingly warm environment, especially the underlying changes in physiology, biochemistry and genetics. Few studies have shown links between physiological mechanisms and heat tolerance phenotypes in an adaptive context. Therefore the overall aim of this thesis was to use the model organism Drosophila melanogaster to elucidate the role of two heat-tolerance candidate genes hsr-omega and hsp90 in thermal adaptation, and to look at this in a physiological context which included examining rates of protein synthesis, a postulated underlying process.Using geographically diverse populations of D. melanogaster from eastern Australia I found that heat tolerance is a plastic trait that depends on rearing temperature and heat-stimulus conditions, and that the adaptive latitudinal clines in heat tolerance depend on these rearing conditions. Protein synthesis rate showed latitudinal clines that also depend on both the temperature at which flies are reared (18 or 25 °C) and heat-stress conditions (either unstressed (basal) or following a 37 °C heat stimulus), and these clines ran in parallel to clines in heat knockdown tolerance, although no evidence that the clines are connected was obtained. Consistent negative correlations between variation in protein synthesis rate and heat knockdown tolerance in a derived North/South hybrid population confirmed the importance of protein synthesis rate as a factor underlying heat tolerance variation within populations. However the latitudinal cline in protein synthesis did not help explain the latitudinal heat tolerance variation as this would require a positive association between the two variables. A gene thought to help control rates of general protein synthesis following heat stimulus, hsr-omega, was investigated for changes in expression across latitude. Clines in basal and heat-stimulated omega-n transcript level suggest that there is adaptive genetic differentiation in hsr-omega expression between populations from different climatic regions. I show for the first time evidence for a link between expression of another heat shock gene, hsp90, and adult heat knockdown tolerance. Tissue levels of hsp90 transcript and protein were negatively associated with tolerance in several independent data sets. Further, this negative association extended to a set of populations from different thermal niches and revealed a positive linear latitudinal cline for both basal hsp90 transcript and protein level. These data suggest that heritable variation in hsp90 expression contributes to traits that facilitate adaptation to different climatic regions, including the clinal variation in thermal tolerance. I also discuss a plausible causal role for hsp90 as a negative regulator of the cellular heat shock response that predicts the above negative hsp90-tolerance association, particularly the interaction between Hsp90 protein and Heat shock factor.Overall these data make a significant contribution to understanding the process of adaption to divergent thermal habitats and to the cellular processes and genes that facilitate thermal adaptation.
Author: Farzana Khan Perveen
Publisher: BoD – Books on Demand
ISBN: 9535138537
Category : Technology & Engineering
Languages : en
Pages : 270
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Book Description
This book contains 12 chapters divided into two sections. Section 1 is "Drosophila - Model for Genetics." It covers introduction, chromosomal polymorphism, polytene chromosomes, chromosomal inversion, chromosomal evolution, cell cycle regulators in meiosis and nongenetic transgenerational inheritance in Drosophila. It also includes ecological genetics, wild-type strains, morphometric analysis, cytostatics, frequencies of early and late embryonic lethals (EEL and LEL) and mosaic imaginal discs of Drosophila for genetic analysis in biomedical research. Section 2 is "Drosophila - Model for Therapeutics." It explains Drosophila as model for human diseases, neurodegeneration, heart-kidney metabolic disorders, cancer, pathophysiology of Parkinson's disease, dopamine, neuroprotective therapeutics, mitochondrial dysfunction and translational research. It also covers Drosophila role in ubiquitin-carboxyl-terminal hydrolase-L1 (UCH-L1) protein, eye development, anti-dUCH antibody, neuropathy target esterase (NTE), organophosphorous compound-induced delayed neuropathy (OPIDN) and hereditary spastic paraplegia (HSP). It also includes substrate specificities, kinetic parameters of recombinant glutathione S-transferases E6 and E7 (DmGSTE6 and DmGSTE7), detoxification and insecticidal resistance and antiviral immunity in Drosophila.
Author: Andrew Cossins
Publisher: Springer Science & Business Media
ISBN: 9400931271
Category : Science
Languages : en
Pages : 346
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Book Description
Temperature is one facet in the mosaic of physical and biotic factors that describes the niche of an animal. Ofthe physical factors it is ecologically the most important. for it is a factor that is all-pervasive and one that. in most environments. lacks spatial or temporal constancy. Evolution has produced a wide variety of adaptive strategies and tactics to exploit or deal with this variable environmental factor. The ease with which temperature can be measured. and controlled experimentally. together with its widespread influence on the affairs of animals. has understandably led to a large. dispersed literature. In spite of this no recent book provides a comprehensive treatment of the biology of animals in relation to temperature. Our intention in writing this book was to fill that gap. We hope we have provided a modern statement with a critical synthesis of this diverse field. which will be suitable and stimulating for both advanced undergraduate and post graduate students of biology. This book is emphatically not intended as a monographical review. as thermal biology is such a diverse. developed discipline that it could not be encompassed within the confines of a book of this size.
Author: Robert M. Tanguay
Publisher: Springer
ISBN: 331916077X
Category : Medical
Languages : en
Pages : 603
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Book Description
Based upon a workshop entitled “The Small HSP World” held in Québec 2-5 October 2014. Twenty-five scientists provided chapters for the book. The chapters are from the best scientists currently working in this field. These colleagues include Arrigo, Benesch, Benjamin, Buchner-Haslbeck-Weinkauf, Benndorf, Boelens, Carra, Chang, Currie, Ecroyd, Emanuelsson, Fu, Garrido, Golenhofen, Gusev, Hightower, Kampinga, Lavoie, MacRae, Quinlan, Tanguay, Vierling, Vigh, Weeks and Wu. Briefly, the book starts with the structure of small heat shock proteins, moving to their functions and finishing with their involvement in diseases. Although this is quite broad, the structural aspect will be the unifying theme of the book.
Author: Michael J. Angilletta Jr.
Publisher: Oxford University Press
ISBN: 0191547204
Category : Science
Languages : en
Pages :
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Book Description
Temperature profoundly impacts both the phenotypes and distributions of organisms. These thermal effects exert strong selective pressures on behaviour, physiology and life history when environmental temperatures vary over space and time. Despite temperature's significance, progress toward a quantitative theory of thermal adaptation has lagged behind empirical descriptions of patterns and processes. In this book, the author draws on theory from the more general discipline of evolutionary ecology to establish a framework for interpreting empirical studies of thermal biology. This novel synthesis of theoretical and empirical work generates new insights about the process of thermal adaptation and points the way towards a more general theory. The threat of rapid climatic change on a global scale provides a stark reminder of the challenges that remain for thermal biologists and adds a sense of urgency to this book's mission. Thermal Adaptation will benefit anyone who seeks to understand the relationship between environmental variation and phenotypic evolution. The book focuses on quantitative evolutionary models at the individual, population and community levels, and successfully integrates this theory with modern empirical approaches. By providing a synthetic overview of evolutionary thermal biology, this accessible text will appeal to both graduate students and established researchers in the fields of comparative, ecological, and evolutionary physiology. It will also interest the broader audience of professional ecologists and evolutionary biologists who require a comprehensive review of this topic, as well as those researchers working on the applied problems of regional and global climate change.
Author: Julien Y Dutheil
Publisher:
ISBN: 9781013271403
Category : Science
Languages : en
Pages : 464
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Book Description
This open access volume presents state-of-the-art inference methods in population genomics, focusing on data analysis based on rigorous statistical techniques. After introducing general concepts related to the biology of genomes and their evolution, the book covers state-of-the-art methods for the analysis of genomes in populations, including demography inference, population structure analysis and detection of selection, using both model-based inference and simulation procedures. Last but not least, it offers an overview of the current knowledge acquired by applying such methods to a large variety of eukaryotic organisms. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, pointers to the relevant literature, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Statistical Population Genomics aims to promote and ensure successful applications of population genomic methods to an increasing number of model systems and biological questions. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.
Author: L. Joseph Su
Publisher: Springer
ISBN: 1447166787
Category : Medical
Languages : en
Pages : 327
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Book Description
This book examines the toxicological and health implications of environmental epigenetics and provides knowledge through an interdisciplinary approach. Included in this volume are chapters outlining various environmental risk factors such as phthalates and dietary components, life states such as pregnancy and ageing, hormonal and metabolic considerations and specific disease risks such as cancer cardiovascular diseases and other non-communicable diseases. Environmental Epigenetics imparts integrative knowledge of the science of epigenetics and the issues raised in environmental epidemiology. This book is intended to serve both as a reference compendium on environmental epigenetics for scientists in academia, industry and laboratories and as a textbook for graduate level environmental health courses. Environmental Epigenetics imparts integrative knowledge of the science of epigenetics and the issues raised in environmental epidemiology. This book is intended to serve both as a reference compendium on environmental epigenetics for scientists in academia, industry and laboratories and as a textbook for graduate level environmental health courses.
Author: Alexey Moskalev
Publisher: Academic Press
ISBN: 012811083X
Category : Medical
Languages : en
Pages : 546
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Book Description
Epigenetics of Aging and Longevity provides an in-depth analysis of the epigenetic nature of aging and the role of epigenetic factors in mediating the link between early-life experiences and life-course health and aging. Chapters from leading international contributors explore the effect of adverse conditions in early-life that may result in disrupted epigenetic pathways, as well as the potential to correct these disrupted pathways via targeted therapeutic interventions. Intergenerational epigenetic inheritance, epigenetic drug discovery, and the role of epigenetic mechanisms in regulating specific age-associated illnesses—including cancer and cardiovascular, metabolic, and neurodegenerative diseases—are explored in detail. This book will help researchers in genomic medicine, epigenetics, and biogerontology better understand the epigenetic determinants of aging and longevity, and ultimately aid in developing therapeutics to extend the human life-span and treat age-related disease. - Offers a comprehensive overview of the epigenetic nature of aging, as well as the impact of epigenetic factors on longevity and regulating age-related disease - Provides readers with clinical and epidemiological evidence for the role of epigenetic mechanisms in mediating the link between early-life experiences, life-course health and aging trajectory - Applies current knowledge of epigenetic regulatory pathways towards developing therapeutic interventions for age-related diseases and extending the human lifespan
Author: Pierre Capy
Publisher: Springer
ISBN: 9789401037556
Category : Science
Languages : en
Pages : 293
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Book Description
Comparison of closely related species is a powerful D. melanogaster. In D. melanogaster, microsatel approach to understanding the changes that have oc lites reveal that West African popUlations are more curred since their divergence from a common ancestor. closely related to non-African populations than to The sibling species Drosophila melanogaster and D. East African popUlations. East African populations are simulans are probably the species pair for which the more variable than West African or non-African popu most genetic data are available. A workshop held at lations, suggesting that East African populations may 1 Gif/Yvette in January 2002 reviewed and discussed more closely reflect African ancestral variability. comparisons between these species, from their ecol Ecophysiology, popUlation dynamics and popula tion structure are also important to understanding the ogy and biogeography to their behavior and DNA evolution of the two species. Genetic diversity (8) polymorphism. is higher in D. simulans (S. Mousset and R. Singh).
