DOCSLIB.ORG

Membrane and Lipid Metabolism Plays an Important Role in Desiccation Resistance in the Yeast Saccharomyces Cerevisiae Qun Ren1, Rebecca Brenner1, Thomas C

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Membrane and Lipid Metabolism Plays an Important Role in Desiccation Resistance in the Yeast Saccharomyces Cerevisiae Qun Ren1, Rebecca Brenner1, Thomas C Ren et al. BMC Microbiology (2020) 20:338 https://doi.org/10.1186/s12866-020-02025-w RESEARCH ARTICLE Open Access Membrane and lipid metabolism plays an important role in desiccation resistance in the yeast Saccharomyces cerevisiae Qun Ren1, Rebecca Brenner1, Thomas C. Boothby2 and Zhaojie Zhang1* Abstract Background: Anhydrobiotes, such as the yeast Saccharomyces cerevisiae, are capable of surviving almost total loss of water. Desiccation tolerance requires an interplay of multiple events, including preserving the protein function and membrane integrity, preventing and mitigating oxidative stress, maintaining certain level of energy required for cellular activities in the desiccated state. Many of these crucial processes can be controlled and modulated at the level of organelle morphology and dynamics. However, little is understood about what organelle perturbations manifest in desiccation-sensitive cells as a consequence of drying or how this differs from organelle biology in desiccation-tolerant organisms undergoing anhydrobiosis. Results: In this study, electron and optical microscopy was used to examine the dynamic changes of yeast cells during the desiccation process. Dramatic structural changes were observed during the desiccation process, including the diminishing of vacuoles, decrease of lipid droplets, decrease in mitochondrial cristae and increase of ER membrane, which is likely caused by ER stress and unfolded protein response. The survival rate was significantly decreased in mutants that are defective in lipid droplet biosynthesis, or cells treated with cerulenin, an inhibitor of fatty acid synthesis. Conclusion: Our study suggests that the metabolism of lipid droplets and membrane may play an important role in yeast desiccation tolerance by providing cells with energy and possibly metabolic water. Additionally, the decrease in mitochondrial cristae coupled with a decrease in lipid droplets is indicative of a cellular response to reduce the production of reactive oxygen species. Keywords: Anhydrobiosis, Desiccation tolerance, Endoplasmic reticulum, Lipid droplets, Lipid metabolism, Mitochondria, Vacuole Background of time. Anhydrobiotes are widespread, having been Water is essential for all life and required for the major- found in the plant, animal (such as tardigrades and nem- ity of the biological processes. At cellular level, water atodes), fungal (such as the budding yeast Saccharomyces plays a pivotal role in proper protein folding and the as- cerevisiae and other non-conventional yeasts), and pro- sembly of phospholipids into biological membranes. karyotic kingdoms of life [1]. Studies have shown that Nevertheless, certain organisms called anhydrobiotes are many anhydrobiotes possess large quantities of non- capable of surviving extreme water loss for a long period reducing sugars (mostly disaccharides, such as trehalose) [2], intrinsically disordered proteins (IDPs) [3, 4] and * Correspondence: [email protected] heat shock proteins [5]. It is believed that these non- 1Department of Zoology and Physiology, University of Wyoming, 1000 E. University Ave, Laramie, WY 82071, USA reducing sugars and IDPs help stabilize and preserve Full list of author information is available at the end of the article both membrane and protein structure and therefore © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Ren et al. BMC Microbiology (2020) 20:338 Page 2 of 13 mitigate the desiccation-induced stresses [6–9]. In bud- could also be vitrified, especially at low water content, ding yeast, dehydration causes dramatic structural forming glassy matrix to avoid the membrane phase changes to almost all major organelles [10–12]. Cell wall transition during dehydration [12, 22–24]. However, components were altered and branched mannoprotein protein misfolding has been observed in desiccated fibrils that are similar to flocculent yeast were observed yeast [5], suggesting that not all proteins, or mem- on the surface of the cell [13]. Plasma membrane invagi- brane are protected. It is unknown whether ‘essential’ nations occur in response to significant decrease of cell proteins and membrane structure (such as nuclear size [14]. Structural changes of the nuclear membrane membrane) are preferentially protected. and condensation of both nuclear and mitochondrial During the desiccation process, intracellular water is DNA has also been reported [13, 14]. Other significant still critical to maintain enzyme activities necessary to changes include vacuoles, lipid droplets and peroxisomes adapt to water loss. Enzyme activities were also observed [12]. Some of the changes are caused by oxidative stress in yeast during long-term desiccation (up to 180 days) during dehydration [15], when the oxidation level in- when trehalose is degraded by trehalases [5]. Little is creases significantly [16]. Multiple pathways have been known about how trehalases remain active in this highly evolved in yeast to mitigate the oxidative damages dehydrated state, suggesting that more mechanisms are caused by desiccation [15]. involved in response to desiccation stress and desicca- The desiccation tolerance of anhydrobiotes is typically tion tolerance. Not surprisingly, the necessity of several not innate, but acquired through some ‘low’ level stress mechanisms to confer desiccation tolerance has also that may or not be related to desiccation. For example, been reported in other systems [6]. in plants acquisition of desiccation tolerance is triggered In this study, transmission electron microscopy (TEM) by dehydration and an increase in the plant hormone was used to examine the ultrastructural changes of yeast abscisic acid [6, 17]. In tardigrade and Saccharomyces during the desiccation process. Because stationary cells cerevisiae, desiccation tolerance is induced by starvation are more desiccation tolerant than the log-phase cells, [4, 18]. Dividing yeast cells growing in glucose have a we speculated that the morphological and physiological minimum tolerance to desiccation [18]. Cells growing in changes of stationary cells, in particular, the increased ethanol-containing medium also has a decreased desic- endoplasmic membrane, decrease in vacuoles and mito- cation tolerance, possibly due to their high degree of un- chondria and modulation of lipid droplet number may saturated fatty acids [19]. Many other factors, such as, play an important role in desiccation tolerance of the cell growth phase, cell cycle stage, growth conditions, yeast. and conditions of dehydration-rehydration etc., also affect the desiccation tolerance. Starvation stress leads to Results significant physiological and morphological changes in Desiccation causes significant structural changes yeast, such as a reduced metabolic rate and thickened Desiccation causes cellular damages even in anhydro- cell wall that is more resistant to enzymatic digestion biotes [25]. In budding yeast, studies have shown that and more thermotolerant [20]. Interestingly, a similar desiccation causes changes of the cellular structure, such gene expression pattern to stationary yeast was identified as cell wall, plasma membrane, nucleus, vacuole, lipid in proliferating yeast that were treated with certain che- droplets, peroxisomes and mitochondria (for reviews, see micals, heat shock or irradiation [21], suggesting that [10–12]). Here, transmission electron microscopy (TEM) yeast may possess a universal response mechanism to was employed to examine and compare the ultrastruc- different environmental stresses. ture of desiccated yeast cells in log- (desiccation-sensi- In plants, the desiccation process starts with moder- tive) and stationary- (desiccation tolerant) phases. First, ate dehydration (initial loss of water) and precedes to we examined the desiccation progress of yeast cells in severe dehydration (loss of almost all water). In the the 15 ml glass tubes (see Method section for details). initial stage of dehydration, the cell volume decreases Cells in the tubes were weighted during the desiccation due to water loss, causing cytoplasmic components to process for weight loss, which was not observed 3.5 days become more crowded, which could cause protein de- (~ 80 h) after desiccation, indicating that cells were fully naturation and membrane fusion [6]. The protective desiccated after 3.5 days of desiccation. To check the disaccharides and other molecules accumulate and remaining amount of extracellular water, the 3.5-day- help forming a water shell around proteins and mem- desiccated cells were
Load more

Recommended publications
  • Desiccation Tolerance and Drought Acclimation in the Antarctic Collembolan Cryptopygus Antarcticus
    Journal of Insect Physiology 54 (2008) 1432–1439 Contents lists available at ScienceDirect Journal of Insect Physiology journal homepage: www.elsevier.com/locate/jinsphys Desiccation tolerance and drought acclimation in the Antarctic collembolan Cryptopygus antarcticus Michael A. Elnitsky a,b,*, Joshua B. Benoit c, David L. Denlinger c, Richard E. Lee Jr.a a Department of Zoology, Miami University, Oxford, OH 45056, United States b Department of Biology, Mercyhurst College, Erie, PA 16546, United States c Department of Entomology, The Ohio State University, Columbus, OH 43210, United States ARTICLE INFO ABSTRACT Article history: The availability of water is recognized as the most important determinant of the distribution and Received 9 June 2008 activity of terrestrial organisms within the maritime Antarctic. Within this environment, arthropods Received in revised form 30 July 2008 may be challenged by drought stress during both the austral summer, due to increased temperature, Accepted 4 August 2008 wind, insolation, and extended periods of reduced precipitation, and the winter, as a result of vapor pressure gradients between the surrounding icy environment and the body fluids. The purpose of the Keywords: present study was to assess the desiccation tolerance of the Antarctic springtail, Cryptopygus Desiccation antarcticus, under ecologically-relevant conditions characteristic of both summer and winter along the Drought acclimation Collembola Antarctic Peninsula. In addition, this study examined the physiological changes and effects of mild Cold-hardiness drought acclimation on the subsequent desiccation tolerance of C. antarcticus.Thecollembolans À1 Cryoprotective dehydration possessed little resistance to water loss under dry air, as the rate of water loss was >20% h at 0% relative humidity (RH) and 4 8C.
    [Show full text]
  • The Evolution of Freeze Tolerance in a Historically Tropical Snail Alice B
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2010 The evolution of freeze tolerance in a historically tropical snail Alice B. Dennis Louisiana State University and Agricultural and Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Recommended Citation Dennis, Alice B., "The ve olution of freeze tolerance in a historically tropical snail" (2010). LSU Doctoral Dissertations. 1003. https://digitalcommons.lsu.edu/gradschool_dissertations/1003 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. THE EVOLUTION OF FREEZE TOLERANCE IN A HISTORICALLY TROPICAL SNAIL A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Biological Sciences by Alice B. Dennis B.S., University of California, Davis 2003 May, 2010 ACKNOWLEDGEMENTS There are many people who have helped make this dissertation possible. I would first like to thank my advisor, Michael E. Hellberg, for his support and guidance. Comments and discussion with my committee: Drs. Sibel Bargu Ates, Robb T. Brumfield, Kenneth M. Brown, and William B. Stickle, have been very helpful throughout the development of this project. I would also like to thank those whose guidance helped lead me down this path, particularly Rick Grosberg, John P. Wares and Alex C. C. Wilson.
    [Show full text]
  • Advances in Understanding of Desiccation Tolerance of Lichens and Lichen-Forming Algae
    plants Review Advances in Understanding of Desiccation Tolerance of Lichens and Lichen-Forming Algae Francisco Gasulla *, Eva M del Campo, Leonardo M. Casano and Alfredo Guéra * Department of Life Sciences, Universidad de Alcalá, Alcalá de Henares, 28802 Madrid, Spain; [email protected] (E.M.d.C.); [email protected] (L.M.C.) * Correspondence: [email protected] (F.G.); [email protected] (A.G.) Abstract: Lichens are symbiotic associations (holobionts) established between fungi (mycobionts) and certain groups of cyanobacteria or unicellular green algae (photobionts). This symbiotic association has been essential in the colonization of terrestrial dry habitats. Lichens possess key mechanisms involved in desiccation tolerance (DT) that are constitutively present such as high amounts of polyols, LEA proteins, HSPs, a powerful antioxidant system, thylakoidal oligogalactolipids, etc. This strategy allows them to be always ready to survive drastic changes in their water content. However, several studies indicate that at least some protective mechanisms require a minimal time to be induced, such as the induction of the antioxidant system, the activation of non-photochemical quenching including the de-epoxidation of violaxanthin to zeaxanthin, lipid membrane remodeling, changes in the proportions of polyols, ultrastructural changes, marked polysaccharide remodeling of the cell wall, etc. Although DT in lichens is achieved mainly through constitutive mechanisms, the induction of protection mechanisms might allow them to face desiccation stress in a better condition. The proportion and relevance of constitutive and inducible DT mechanisms seem to be related to the ecology at which lichens are adapted to. Citation: Gasulla, F.; del Campo, E.M; Casano, L.M.; Guéra, A.
    [Show full text]
  • Desiccation Tolerance of Adult Stem Cells in the Presence of Trehalose and Glycerol
    The Open Biotechnology Journal, 2008, 2, 211-218 211 Open Access Desiccation Tolerance of Adult Stem Cells in the Presence of Trehalose and Glycerol Surbhi Mittal and Ram V. Devireddy* Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA, USA Abstract: Development of protocols for storing desiccated cells at ambient temperatures offers tremendous economic and practical advantages over traditional storage procedures like cryopreservation and freeze-drying. As a first step for devel- oping such procedures for adult stem cells, we have measured the post-rehydration membrane integrity (PRMI) of two passages, Passage-0 (P0) and Passage-1 (P1), of human adipose-derived stem cells (ASCs). ASCs were dried using a con- vective stage at three different drying rates (slow, moderate and rapid) in D-PBS with trehalose (50 mM) and glycerol (384 mM). ASCs were incubated in the drying media for 30 mins prior to drying at the prescribed rate on the convective stage for 30 mins. After drying, the ASCs were stored for 48 hrs in three different conditions: i) at ambient temperature, ii) in plastic bags at ambient temperature and iii) in vacuum sealed plastic bags at ambient temperature. PRMI was as- sessed after incubating the rehydrated ASCs with stromal medium for a further 48 hrs. Our measurements show that the PRMI of ASCs was: i) higher when ASCs were dried slowly; ii) increased when they were stored in vacuum as opposed to at ambient or in plastic bags; and iii) decreased with increasing passage of ASCs, i.e. under similar drying and storage conditions P0 ASCs had higher PRMI than P1 ASCs.
    [Show full text]
  • Metabolic Shift from Glycogen to Trehalose Promotes Lifespan
    Metabolic shift from glycogen to trehalose promotes PNAS PLUS lifespan and healthspan in Caenorhabditis elegans Yonghak Seoa, Samuel Kingsleya, Griffin Walkera, Michelle A. Mondouxb, and Heidi A. Tissenbauma,c,1 aDepartment of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School (UMMS), Worcester, MA 01605; bDepartment of Biology, College of the Holy Cross, Worcester, MA 01610; and cProgram in Molecular Medicine, UMMS, Worcester, MA 01605 Edited by Gary Ruvkun, Massachusetts General Hospital, Boston, MA, and approved February 13, 2018 (received for review August 10, 2017) As Western diets continue to include an ever-increasing amount of dition of trehalose to the standard E. coli diet promotes longevity sugar, there has been a rise in obesity and type 2 diabetes. To avoid (27) in contrast to the toxicity caused by the addition of glucose metabolic diseases, the body must maintain proper metabolism, even (5–8). Furthermore, mutants have been identified that are long on a high-sugar diet. In both humans and Caenorhabditis elegans, lived and store increased trehalose (27). Therefore, an association excess sugar (glucose) is stored as glycogen. Here, we find that ani- between longevity and trehalose has been established. Mammals do mals increased stored glycogen as they aged, whereas even young not store sugar as trehalose but do possess the enzyme trehalase to adult animals had increased stored glycogen on a high-sugar diet. breakdown ingested trehalose (28). Further, oral supplementation Decreasing the amount of glycogen storage by modulating the C. of trehalose has been shown to improve glucose tolerance in in- elegans glycogen synthase, gsy-1, a key enzyme in glycogen synthe- dividuals at high risk for developing type 2 diabetes (29) and can sis, can extend lifespan, prolong healthspan, and limit the detrimental improve recovery from traumatic brain injury in mice (30).
    [Show full text]
  • Geographic Variation in Adult and Embryonic Desiccation Tolerance In
    bioRxiv preprint doi: https://doi.org/10.1101/314351; this version posted October 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Geographic variation in adult and embryonic desiccation tolerance in a terrestrial-breeding frog Rudin-Bitterli, T.S.1,2 *, Evans, J.P.1,2 & Mitchell, N.J.1 1 - School of Biological Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia 2 - Centre for Evolutionary Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia Keywords: amphibians, desiccation tolerance, intra-specific variation, climate change, adaptation, phenotypic plasticity, environmental sensitivity 1 bioRxiv preprint doi: https://doi.org/10.1101/314351; this version posted October 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. ABSTRACT Intra-specific variation in the ability of individuals to tolerate environmental perturbations is often neglected when considering the impacts of climate change. Yet this information is potentially crucial for mitigating any deleterious effects of climate change on threatened species. Here we assessed patterns of intra-specific variation in desiccation tolerance in the frog Pseudophryne guentheri, a terrestrial-breeding species experiencing a drying climate. Adult frogs were collected from six populations across a rainfall gradient and their dehydration and rehydration rates were assessed.
    [Show full text]
  • Membrane and Lipid Metabolism Plays an Important Role in Desiccation Resistance in the Yeast Saccharomyces Cerevisiae
    Membrane and lipid metabolism plays an important role in desiccation resistance in the yeast Saccharomyces cerevisiae Qun Ren University of Wyoming Rebecca Brenner University of Wyoming Thomas C. Boothby University of Wyoming Zhaojie Zhang ( [email protected] ) University of Wyoming https://orcid.org/0000-0001-6790-6243 Research article Keywords: anhydrobiosis, desiccation tolerance, endoplasmic reticulum, lipid droplets, lipid metabolism, mitochondria, vacuole Posted Date: October 27th, 2020 DOI: https://doi.org/10.21203/rs.3.rs-48916/v3 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Version of Record: A version of this preprint was published on November 10th, 2020. See the published version at https://doi.org/10.1186/s12866-020-02025-w. Page 1/23 Abstract Background Anhydrobiotes, such as the yeast Saccharomyces cerevisiae, are capable of surviving almost total loss of water. Desiccation tolerance requires an interplay of multiple events, including preserving the protein function and membrane integrity, preventing and mitigating oxidative stress, maintaining certain level of energy required for cellular activities in the desiccated state. Many of these crucial processes can be controlled and modulated at the level of organelle morphology and dynamics. However, little is understood about what organelle perturbations manifest in desiccation-sensitive cells as a consequence of drying or how this differs from organelle biology in desiccation-tolerant organisms undergoing anhydrobiosis. Results In this study, electron and optical microscopy was used to examine the dynamic changes of yeast cells during the desiccation process. Dramatic structural changes were observed during the desiccation process, including the diminishing of vacuoles, decrease of lipid droplets, decrease in mitochondrial cristae and increase of ER membrane, which is likely caused by ER stress and unfolded protein response.
    [Show full text]
  • Cuticular Lipid Mass and Desiccation Rates in Glossina Pallidipes: Interpopulation Variation Russell A
    Entomology Publications Entomology 2007 Cuticular lipid mass and desiccation rates in Glossina pallidipes: interpopulation variation Russell A. Jurenka Iowa State University, [email protected] John S. Terblanche Stellenbosch University C. Jaco Klok Stellenbosch University Steven L. Chown Stellenbosch University Elliot S. Krafsur Iowa State University Follow this and additional works at: http://lib.dr.iastate.edu/ent_pubs Part of the Biochemistry Commons, Entomology Commons, Genetics Commons, and the Structural Biology Commons The ompc lete bibliographic information for this item can be found at http://lib.dr.iastate.edu/ ent_pubs/276. For information on how to cite this item, please visit http://lib.dr.iastate.edu/ howtocite.html. This Article is brought to you for free and open access by the Entomology at Iowa State University Digital Repository. It has been accepted for inclusion in Entomology Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Cuticular lipid mass and desiccation rates in Glossina pallidipes: interpopulation variation Abstract Tsetse flies, Glossina pallidipes (Diptera: Glossinidae) are said to have strong dispersal tendencies. Gene flow among these populations is estimated to be the theoretical equivalent of no more than one or two reproducing flies per generation, thereby raising the hypothesis of local regimes of natural selection. Flies were sampled from four environmentally diverse locations in Kenya to determine whether populations are homogeneous in desiccation tolerance and cuticular lipids. Cuticular hydrocarbon fractions known to act as sex pheromones do not differ among populations, thereby eliminating sexual selection as an isolating mechanism. Cuticular lipid quantities vary among populations and are not correlated with prevailing temperatures, humidities, and normalized density vegetation indices.
    [Show full text]
  • Effects of Starvation and Desiccation on Energy Metabolism in Desert and Mesic Drosophila M.T
    Journal of Insect Physiology 49 (2003) 261–270 www.elsevier.com/locate/jinsphys Effects of starvation and desiccation on energy metabolism in desert and mesic Drosophila M.T. Marron a,1, T.A. Markow b, K.J. Kain a,2, A.G. Gibbs a,∗ a Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E. Lowell St., Tucson, AZ 85721, USA b Center for Insect Science, University of Arizona, 1037 E. Lowell St., Tucson, AZ 85721, USA Received 23 July 2002; received in revised form 11 December 2002; accepted 11 December 2002 Abstract Energy availability can limit the ability of organisms to survive under stressful conditions. In Drosophila, laboratory experiments have revealed that energy storage patterns differ between populations selected for desiccation and starvation. This suggests that flies may use different sources of energy when exposed to these stresses, but the actual substrates used have not been examined. We measured lipid, carbohydrate, and protein content in 16 Drosophila species from arid and mesic habitats. In five species, we measured the rate at which each substrate was metabolized under starvation or desiccation stress. Rates of lipid and protein metab- olism were similar during starvation and desiccation, but carbohydrate metabolism was several-fold higher during desiccation. Thus, total energy consumption was lower in starved flies than desiccated ones. Cactophilic Drosophila did not have greater initial amounts of reserves than mesic species, but may have lower metabolic rates that contribute to stress resistance. 2003 Elsevier Science Ltd. All rights reserved. Keywords: Carbohydrate; Desiccation; Drosophila; Energetics; Lipid; Metabolic rate; Starvation; Stress resistance 1.
    [Show full text]
  • Membrane Stabilization and Desiccation Tolerance During Seed Corn (Zea Mays L.) Drying Yuguang Chen Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1990 Membrane stabilization and desiccation tolerance during seed corn (Zea mays L.) drying Yuguang Chen Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agricultural Science Commons, Agriculture Commons, and the Agronomy and Crop Sciences Commons Recommended Citation Chen, Yuguang, "Membrane stabilization and desiccation tolerance during seed corn (Zea mays L.) drying " (1990). Retrospective Theses and Dissertations. 9426. https://lib.dr.iastate.edu/rtd/9426 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. mmi INFORMATION TO USERS The most advanced technology has been used to photograph and reproduce this manuscript from the microfihn master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter (ace, while others may be from any type of computer printer. The quality of this repiodnctioB Is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.
    [Show full text]
  • Ecological and Functional Genomic Aspects of Desiccation Tolerance In
    Natural variation, laboratory selection, and genomics of desiccation tolerance in Drosophila Subhash Rajpurohit Water to terrestrial life Challenge is… How to conserve it??? 30 percent; arid 2 Size and Water loss relations 3 Chemical Nature of Water Water 4 Resistance to desiccation can involve one or more adaptive mechanisms This resistance could be accomplished in three ways: by increasing the amount of water in the body, by tolerating the loss of a greater percentage of body water (dehydration tolerance) or By reducing rates of water loss. 5 Insects can lose water through various routes… Various excretions; <20% (oral secretions, feces, & eggs) Transpiration through cuticle; >80% (evaporation from the tracheal system through open spiracles) Gibbs et al., 2003. J Exp Biol 6 Water Balance 7 Desiccation tolerance in Drosophila… I. Natural variation II. Artificial selection II. Genomics ecology » organism » genes 8 Drosophila melanogaster as a model organism ‘colonization’ <300 yr <300 yr I. Natural Variation 10 Six geographical locations at four different Desiccation tolerance thermal conditions - developmental temperatures of 18 °C 25 °C 29 °C & - adult female exposure to dormancy- inducing conditions of 11˚C, 9L:15D) Molecular Ecology 2018, under review 11 Geographic cline of relative desiccation tolerance of six drosophilid species from the Indian subcontinent. Values are relative to the mean survival time for all populations assayed within each species. Indian subcontinent Rajpurohit et al. 2013, CBP-A 12 Seasonal variations; Indian subcontinent North 38 36 34 32 30 C) ° 28 Center 26 24 22 Jammu (North) Temperature ( Temperature CV Temperature 20 Nagpur (Center) Trivandrum (South) 18 16 South 14 12 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rajpurohit et al.
    [Show full text]
  • Spatiotemporal Patterns of Desiccation Tolerance in Natural Populations of Drosophila Melanogaster
    bioRxiv preprint doi: https://doi.org/10.1101/079616; this version posted October 7, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Spatiotemporal patterns of desiccation tolerance in natural populations of Drosophila 2 melanogaster 3 1Subhash Rajpurohit, 2Eran Gefen, 3Alan Bergland, 4Dmitri Petrov, 5Allen G Gibbs, and 1Paul S 4 Schmidt 5 1Department of Biology, University of Pennsylvania, 433 S. University Ave, Philadelphia, PA 6 19104, USA 7 2Department of Biology, University of Haifa-Oranim, Tivon 36006, Israel 8 3Department of Biology, University of Virginia, Charlottesville, VA 22903 9 4Department of Biology, 371 Serra St., Stanford University, Stanford, CA 94305, USA 10 5School of Life Sciences, University of Nevada, Las Vegas, USA 11 12 Running title: Drought tolerance in temperate Drosophila 13 Keywords: Desiccation tolerance, Drosophila, Geographical variation, North America. 14 15 Correspondence 16 Paul Schmidt 17 Email: [email protected]; Phone: +1-215-898-7356; Fax: +1-215-898-8780 1 bioRxiv preprint doi: https://doi.org/10.1101/079616; this version posted October 7, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 18 Abstract Water availability is a major environmental challenge to a variety of terrestrial 19 organisms. In insects, desiccation tolerance varies predictably over various
    [Show full text]