Mfaveolata single-time point bleaching experiment
Ontology highlight
ABSTRACT:
ORGANISM(S): Orbicella faveolata
PROVIDER: GSE10630 | GEO | 2008/05/31
SECONDARY ACCESSION(S): PRJNA108841
REPOSITORIES: GEO
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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
2008-05-31 | GSE10632 | 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, 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:Coral bleaching occurs in response to numerous abiotic stressors, the ecologically most relevant of which is hyperthermic stress due to increasing seawater temperatures. Bleaching events can span large geographic areas and are currently a potent threat to coral reefs worldwide. Much effort has been focused on understanding the molecular and cellular events underlying bleaching, and these studies have mainly utilized heat and light stress regimes. In an effort to determine whether different stressors share common bleaching mechanisms, we used cDNA microarrays for the corals Acropora palmata and Montastraea faveolata (containing > 10,000 features) to measure differential gene expression during darkness stress. This is the first coral microarray experiment aimed at darkness stress, and the first for these species to interrogate gene expression at such a large scale. Our results reveal a striking transcriptomic response to darkness in A. palmata involving chaperone and antioxidant up-regulation, growth arrest, and metabolic modifications. As these responses were also measured during thermal stress, our results suggest that different stressors may share common bleaching mechanisms. Furthermore, our results point to ER stress as a critical cellular event involved in darkness-specific (and possibly more general) molecular bleaching mechanisms. On the other hand, we identified a meager transcriptomic response to darkness in M. faveolata where gene expression differences between host colonies and/or sampling locations were greater than differences between control and stressed fragments. To this end, we discuss the importance of factors related to host genotype, Symbiodinium genotype, and the abiotic environment that influence host gene expression and thereby can hinder an investigator’s ability to measure gene expression during a condition of interest.
2011-03-23 | GSE27024 | GEO
Project description:Coral bleaching occurs in response to numerous abiotic stressors, the ecologically most relevant of which is hyperthermic stress due to increasing seawater temperatures. Bleaching events can span large geographic areas and are currently a potent threat to coral reefs worldwide. Much effort has been focused on understanding the molecular and cellular events underlying bleaching, and these studies have mainly utilized heat and light stress regimes. In an effort to determine whether different stressors share common bleaching mechanisms, we used cDNA microarrays for the corals Acropora palmata and Montastraea faveolata (containing > 10,000 features) to measure differential gene expression during darkness stress. This is the first coral microarray experiment aimed at darkness stress, and the first for these species to interrogate gene expression at such a large scale. Our results reveal a striking transcriptomic response to darkness in A. palmata involving chaperone and antioxidant up-regulation, growth arrest, and metabolic modifications. As these responses were also measured during thermal stress, our results suggest that different stressors may share common bleaching mechanisms. Furthermore, our results point to ER stress as a critical cellular event involved in darkness-specific (and possibly more general) molecular bleaching mechanisms. On the other hand, we identified a meager transcriptomic response to darkness in M. faveolata, where gene expression differences between host colonies and/or sampling locations were greater than differences between control and stressed fragments. To this end, we discuss the importance of factors related to host genotype, Symbiodinium genotype, and the abiotic environment that influence host gene expression and thereby can hinder an investigator’s ability to measure gene expression during a condition of interest.
2011-03-23 | GSE27022 | GEO
Project description:Coral bleaching occurs in response to numerous abiotic stressors, the ecologically most relevant of which is hyperthermic stress due to increasing seawater temperatures. Bleaching events can span large geographic areas and are currently a potent threat to coral reefs worldwide. Much effort has been focused on understanding the molecular and cellular events underlying bleaching, and these studies have mainly utilized heat and light stress regimes. In an effort to determine whether different stressors share common bleaching mechanisms, we used cDNA microarrays for the corals Acropora palmata and Montastraea faveolata (containing > 10,000 features) to measure differential gene expression during darkness stress. This is the first coral microarray experiment aimed at darkness stress, and the first for these species to interrogate gene expression at such a large scale. Our results reveal a striking transcriptomic response to darkness in A. palmata involving chaperone and antioxidant up-regulation, growth arrest, and metabolic modifications. As these responses were also measured during thermal stress, our results suggest that different stressors may share common bleaching mechanisms. Furthermore, our results point to ER stress as a critical cellular event involved in darkness-specific (and possibly more general) molecular bleaching mechanisms. On the other hand, we identified a meager transcriptomic response to darkness in M. faveolata where gene expression differences between host colonies and/or sampling locations were greater than differences between control and stressed fragments. To this end, we discuss the importance of factors related to host genotype, Symbiodinium genotype, and the abiotic environment that influence host gene expression and thereby can hinder an investigator’s ability to measure gene expression during a condition of interest. We employed a reference design where all control and dark-stressed samples were compared to a pooled reference aRNA sample composed of aRNA from all fragments. Since all RNA samples were compared to the reference sample, direct comparisons of gene expression across all time points and conditions can be performed.
2011-03-22 | E-GEOD-27024 | biostudies-arrayexpress
Project description:Coral bleaching occurs in response to numerous abiotic stressors, the ecologically most relevant of which is hyperthermic stress due to increasing seawater temperatures. Bleaching events can span large geographic areas and are currently a potent threat to coral reefs worldwide. Much effort has been focused on understanding the molecular and cellular events underlying bleaching, and these studies have mainly utilized heat and light stress regimes. In an effort to determine whether different stressors share common bleaching mechanisms, we used cDNA microarrays for the corals Acropora palmata and Montastraea faveolata (containing > 10,000 features) to measure differential gene expression during darkness stress. This is the first coral microarray experiment aimed at darkness stress, and the first for these species to interrogate gene expression at such a large scale. Our results reveal a striking transcriptomic response to darkness in A. palmata involving chaperone and antioxidant up-regulation, growth arrest, and metabolic modifications. As these responses were also measured during thermal stress, our results suggest that different stressors may share common bleaching mechanisms. Furthermore, our results point to ER stress as a critical cellular event involved in darkness-specific (and possibly more general) molecular bleaching mechanisms. On the other hand, we identified a meager transcriptomic response to darkness in M. faveolata, where gene expression differences between host colonies and/or sampling locations were greater than differences between control and stressed fragments. To this end, we discuss the importance of factors related to host genotype, Symbiodinium genotype, and the abiotic environment that influence host gene expression and thereby can hinder an investigator’s ability to measure gene expression during a condition of interest. We employed a reference design where all control and dark-stressed samples were compared to a pooled reference aRNA sample composed of aRNA from all fragments. Since all RNA samples were compared to the reference sample, direct comparisons of gene expression across all time points and conditions can be performed.
2011-03-22 | E-GEOD-27022 | biostudies-arrayexpress
Project description:The emergence of genomic tools for reef-building corals and symbiotic anemones comes at a time when alarming losses in coral cover are being observed worldwide. These tools hold great promise in elucidating novel and unforeseen cellular processes underlying the successful mutualism between corals and their algal endosymbionts (Symbiodinium spp.). Since thermal stress triggers a breakdown in the symbiosis (coral bleaching), measuring the transcriptomic response to thermal stress-induced bleaching offers an extraordinary view of the cellular processes specific to coral-algal symbioses. In the present study, we utilized a cDNA microarray containing 2,059 genes of the Caribbean Elkhorn coral Acropora palmata to identify genes differentially expressed upon thermal stress. Fragments from four separate colonies were exposed to elevated temperature (3˚C increase) for two days, and samples were frozen for microarray analysis after 24 and 48 hours. Fragments experienced a 60% reduction in algal cell density after two days. 204 genes were differentially expressed in samples collected one day after thermal stress; in samples collected after two days, 104 genes. Annotations of the differentially expressed genes indicate a conserved cellular stress response in A. palmata involving: 1) growth arrest; 2) chaperone activity; 3) nucleic acid stabilization and repair; and 4) the removal of damaged macromolecules. Other differentially expressed processes include sensory perception, metabolite transfer between host and symbiont, nitric oxide signaling, and modifications to the actin cytoskeleton and extracellular matrix. The results are also compared to those from a previous coral microarray study of thermal stress in Montastraea faveolata.
2009-10-31 | GSE16151 | 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
Project description:Given the overwhelming evidence that symbiont genotypes differentially affect host processes such as growth, bleaching susceptibility, and nutrient acquisition, we set out to measure gene expression differences in fragments of Montastraea faveolata harboring two different clades of Symbiodinium. On the reefs near Puerto Morelos, México, colonies of M. faveolata are known to shift algal symbiont clade with depth, often associating with clade A at the top, clade B in the middle, and clade C near the bottom of the colony. By measuring photosynthetic efficiency and gene expression in control and heat-stressed fragments containing either clade B, clade C, or a mix of both, we found that: 1) the algal response to thermal stress is due to both host and algal factors; 2) fragments of M. faveolata express different genes in response to sub-bleaching thermal stress depending on algal genotype; 3) the overall effect of heat stress on coral gene expression is less significant than the effect of housing different zooxanthellae types. Overall, we present convincing evidence that different Symbiodinium clades may be functionally distinct, which in turn, greatly influences host gene expression.
2009-05-31 | GSE12809 | GEO