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PROVIDER: PRJNA1013245 | ENA |
REPOSITORIES: ENA
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Project description:Heat-evolved Symbiodiniaceae can improve the physiological performances of their coral host under heat stress, but their gene expression responses to heat remained unknown. We explore here the transcriptomic basis of differential thermal stress responses between in hospite wild-type and heat-evolved Cladocopium proliferum strains and their coral host Platygyra daedealea.
2024-03-01 | GSE256269 | GEO
Project description:Transcriptional profiling of gene responses in liver in the coral reef fish Pomacentrus moluccensis in response to different types of environmental stress: cold, heat, hypoxic and hyposmotic shock. Goal was to determine the common effects of different types of environmental stress on gene expression as well as responses unique to different stressors. Abstract from Kassahn et al. BMC Genomics (2007) 8:358 Background While our understanding of the importance of transcriptional regulation for biological function is continuously growing, we still know comparatively little about how environmentally-induced stress affects gene expression in vertebrates and how consistent transcriptional stress responses are across different types of environmental stress. Results In this study, we looked for a genetic measure of environmental stress and used a multi-stressor approach to identify components of a common stress response as well as components unique to different types of environmental stress. We exposed individuals of the coral reef fish Pomacentrus moluccensis to hypoxic, hyposmotic, cold and heat shock and measured the responses of approximately 16,000 genes in liver. We also compared winter and summer responses to heat shock to examine the capacity for such responses to vary with acclimation to different ambient temperatures. We identified a series of gene functions that were consistently involved in all stress responses examined here, suggesting common effects of stress on biological function. These common responses were achieved by the regulation of largely independent sets of genes and the responses of individual genes varied greatly across different stress types. However, we were able to identify groups of co-regulated genes, the genes within which shared similar functions. Given current estimates of climatic change, we were particularly interested in the response to prolonged heat exposure. In total, 324 gene loci were differentially expressed following exposure to heat over five days. The functions of these heat-responsive genes suggest that prolonged heat stress leads to oxidative stress and protein damage, challenge of the immune system, and a re-allocation of energy sources. Conclusion This is the first environmental genomic study to measure gene regulation in response to different environmental stressors in a natural population of a warm-adapted ectothermic vertebrate. This study offers insight into the effects of environmental stress on biological function and sheds light on the expected sensitivity of coral reef fishes to elevated temperatures in the future. Keywords: Stress response
2007-10-15 | GSE7499 | GEO
Project description:Telomere DNA length is a complex trait controlled both by multiple loci and environmental factors. Even though the use of telomere DNA length measurement, as a method of assessing stress accumulation and predicting how this will influence survival, is currently being studied in numerous human cohort studies, the importance of telomere length for stress response in ecological studies remains at its infancy. Here, we investigated the telomere changes occurring in the symbiotic coral Stylophora pistillata that has experienced a continuous darkness over 6 months. This stress condition led to the loss of its symbionts, as what is also observed when bleaching occurs in the field at a large-scale due to climate changes and anthropogenic activities, threatening the worldwide reef ecosystem. We found that the continuous darkness condition was associated to telomere DNA length shortening and a downregulation of the expression of the telomere-associated protein POT2. These results pave the way for future studies on the role of telomere in coral stress response and the importance of telomere dysregulation in endangered coral species
2021-09-20 | GSE171268 | GEO
Project description:Over the past several decades, corals worldwide have been affected by global warming, experiencing severe bleaching events that have often lead to coral death. The symbiotic Red Sea coral Stylophora pistillata is considered an opportunistic ‘r’ strategist, thriving in relatively unstable and unpredictable environments, and it is considered a stress-tolerant species. This study aimed to examine S. pistillata gene expression and to clarify the cellular pathways that are active during short-term heat stress caused by an increase from 24°C to 34°C over a 10-day period. Total RNA was extracted from heat-stressed coral fragments, labeled and hybridized against a designated S. pistillata custom microarray containing approximately 12,000 genes. Our results show that the heat stress reaction was sighted from 32°C and intensified significantly after 34°C treatment. Protein interaction networks of up- and down-regulated genes were constructed. The main clustering groups of up-regulated genes were ER stress and ER protein folding, cell cycle, ubiquitin-mediated proteolysis, cell death and cell death regulation and cellular stress response genes. These genes were enriched in cellular pathways related to the unfolded protein response (UPR) in the ER, ER-associated degradation (ERAD) and ubiquitin-mediated proteolysis. An analysis of the down-regulated genes yielded different clusters of genes related to extracellular matrix and actin organization, collagen, negative regulation of cell death and the Notch and Wnt signaling pathways. Genes encoding redox regulation proteins and molecular chaperones may be considered accurate “early warning genes”, while genes related to sensing and repairing DNA damage are severe heat-related genes. Here, we suggest that during short-term heat stress, S. pistillata might divert cellular energy into mechanisms such as UPR and ERAD at the expense of growth and biomineralization processes in an effort to recover from the stress.
2014-12-22 | GSE47779 | GEO
Project description:In this study, we examined the very early transcriptional response of aposymbiotic coral larval host (still not engaged in symbiosis) to hyperthermal stress. This experimental setting provided a scenario and opportunity to study the direct effect of environmental stressors on the host cell per se. Using a cDNA microarray constructed for Acropora millepora and Q-RT-PCR assays, we identified a number of genes that were significantly up- and down-regulated with increase of seawater temperature. Down-regulation of several key component of DNA/RNA metabolism was detected implying inhibition of this cellular metabolic process, however the down-regulation of overall protein synthesis was not simple and random, which suggest that the response to stress is a more complicated adjustment to the metabolic needs of the cell. We identified four significant outcomes during the very early hours of the transcriptional response to hyperthermal stress in coral larvae. First, molecular chaperones responded to hyperthermal stress by increasing their expression as expected, but the response was immediate and extremely rapid during the first 3 hours of heat exposure. Secondly, elevated temperature triggers down-regulation of a fluorescent protein homolog, DsRed-type FP, suggesting that this gene might be used as a potential molecular marker for monitoring hyperthermal stress in nature. Thirdly, the downregulation of a coral mannose-binding lectin under hyperthermal stress might compromise the coral immune defense and bring about susceptibility to pathogenic diseases. And lastly, an absence in the response of oxidative stress genes in aposymbiotic coral larvae during the early hours to hyperthermal stress suggest that the up-regulation of cnidarian host oxidative stress genes reported during thermal stress in algal/host symbiosis might be triggered directly by ROS generated by photosynthetic-dysfunctionally algal endosymbionts that diffuse into host cells, as very little ROS seems to be produced by the host cells from thermal-associated host cellular damage.
2009-08-11 | GSE16351 | GEO
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response; coral bleaching 5 control and 5 heat-stressed RNA samples were hybridized in a 5-replicate dye-swap design (10 total hyb's).
2008-05-31 | E-GEOD-10630 | biostudies-arrayexpress
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response, time course, coral bleaching Time course with 4 time points and 4 biological replicates per time point. Each biological replicate at each time point was hybridized to a pooled reference control sample containing RNA from all control non-heat-stressed coral fragments.
2008-05-31 | E-GEOD-10632 | biostudies-arrayexpress
Project description:The potential to adapt to a changing climate depends in part upon the standing genetic variation present in wild populations. In corals, the dispersive larval phase is particularly vulnerable to the effects of environmental stress. Larval survival and response to stress during dispersal and settlement will play a key role in the persistence of coral populations. To test the hypothesis that larval transcription profiles reflect population specific responses to thermal stress, symbiont-free gametes of the scleractinian coral Montastraea faveolata were collected from Florida and Mexico and raised under normal and elevated temperatures. These populations have been shown to exchange larvae frequently enough to prevent significant differentiation of neutral loci. Differences among thousands of genes were simultaneously characterized using microarrays, allowing investigation of gene expression patterns among wild populations under stressful environmental conditions. Results show site-specific signatures of gene expression in larvae of a reef-building coral from different parts of its range (despite low genetic divergence), and reveal both local and general components of stress response during later stages of larval development. These results provide evidence of site-specific variation in the face of gene flow, which may represent functional genetic variation in different subpopulations, and support the idea that coral host genomes may indeed house the adaptive potential needed to deal with changing environmental conditions.
2010-06-23 | GSE19998 | GEO
Project description:Thermal history plays a role in the response of corals to subsequent heat stress. Prior heat stress can have a profound impact on later thermal tolerance, but the mechanism for this plasticity is not clear. The understanding of gene expression changes behind physiological acclimatization is critical in forecasts of coral health in impending climate change scenarios. Acropora millepora fragments were preconditioned to sublethal bleaching threshold stress for a period of 10 days; this prestress conferred bleaching resistance in subsequent thermal challenge, in which non-preconditioned coral bleached. Using microarrays, we analyze the transcriptomes of the coral host, comparing the bleaching-resistant preconditioned treatment to non-preconditioned and control treatments.
2012-11-29 | GSE41435 | GEO