Microarray analysis highlights immune response of Pacific oysters as a determinant of resistance to summer mortality
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ABSTRACT:
ORGANISM(S): Magallana gigas
PROVIDER: GSE25614 | GEO | 2011/04/22
SECONDARY ACCESSION(S): PRJNA134269
REPOSITORIES: GEO
Similar Datasets
Project description:Summer mortality of the Pacific oyster Crassostrea gigas is the result of a complex interaction between oysters, their environment and pathogens. Heredity appears to be a major factor determining the sensitivity of oysters to summer mortality, allowing resistant (R) and susceptible (S) lines to be produced. We conducted genome-wide expression profiling of R and S gonads during the 3-month period preceding a summer mortality event using a 9K cDNA microarray that we designed. This transcriptional analysis provides new indications to define markers for Quantitative Trait Loci searches and functional studies, and evaluates the potential role of each gene in the resistance to summer mortality
2009-08-15 | GSE16448 | GEO
Project description:Summer mortality of Crassostrea gigas is the result of a complex interaction between oysters, their environment and pathogens. A large genetic basis and a high heritability were demonstrated for the observed variation in resistance to summer mortality, which offered the possibility to develop lines of oysters that were resistant (R) or susceptible (S) to summer mortality. Previously, genome-wide expression profiling of R and S oyster gonads highlighted reproduction and antioxidant defense as constitutive pathways that operate differentially between these two lines. Here, we show that signaling in innate immunity also operates differentially between these lines and we postulated that it is at the main origin of their difference of survival in the field. From the already published microarray data, we employed an ANOVA analysis that reveals a specific “immune” profile at the date preceding the mortality. In addition, we conducted a microarray profiling of two other tissues, gills and muscle, that also showed an over-representation of the immune genes (46%) among the selected genes. Eleven genes were pinpointed to be simultaneously differentially expressed between R and S lines in the three tissues. Among them, ten are related to “Immune Response”. The kinetics of their mRNA levels appeared clearly different between lines and suggests that in environment, R oysters had the capacity to modulate signaling in innate immunity whereas S oysters did not. This study enhances our understanding of the complex summer mortality syndrome and provides candidates of interest for further functional and genetics studies. For microarray analysis, R and S oysters were sampled three times (dates 1 to 3: May 25, June 6, and June 20, respectively). On each date, 3 replicates of 8 oysters were sampled from each line (R and S) for three tissues (gonad, muscle and fills) and all the samples prepared for total RNA extraction. Furthermore, the entire tissues of 10 wild oysters were collected, pooled and homogenized to constitute a single total RNA sample for use as a reference in all slide hybridizations and RT-PCR analysis. For microarray hybridizations, 5µg of total RNA were directly labeled by reverse transcription and then purified using the Direct ShipShot Labeling kit (Promega). This reaction was performed for each of the 18 samples, with Cy5 (red) incorporation. The reference sample was Cy3-labeled (green) in 18 separate tubes following the same protocol. The 18 Cy3-labeled cDNAs were next pooled, and then divided once more into 18 samples to obtain a homogeneous reference. Equimolar amounts of cDNA samples and cDNA reference labeled with Cy5 and Cy3, respectively, were SpeedVac evaporated and mixed into a single pool with the hybridization buffer (ChipHyb™ hybridization buffer, Ventana Discovery, Tucson, AZ, USA). They were then co-hybridized on the same microarray slide, in a Ventana hybridization station (Ventana Discovery, Tucson, AZ, USA). The data submitted here correspond to the mean of the three replicates for each line and each date, representing 18 samples.
2011-04-22 | E-GEOD-25614 | biostudies-arrayexpress
Project description:Summer mortality of the Pacific oyster Crassostrea gigas is the result of a complex interaction between oysters, their environment and pathogens. Heredity appears to be a major factor determining the sensitivity of oysters to summer mortality, allowing resistant (R) and susceptible (S) lines to be produced. We conducted genome-wide expression profiling of R and S gonads during the 3-month period preceding a summer mortality event using a 9K cDNA microarray that we designed. This transcriptional analysis provides new indications to define markers for Quantitative Trait Loci searches and functional studies, and evaluates the potential role of each gene in the resistance to summer mortality For microarray analysis, R and S oysters were sampled four times (dates 1 to 4: May 9, May 25, June 6, and June 20, respectively). On each date, 3 replicates of 8 oysters were sampled from each line (R and S) and the gonads prepared for total RNA extraction. Furthermore, the entire tissues of 10 wild oysters were collected, pooled and homogenized to constitute a single total RNA sample for use as a reference in all slide hybridizations and RT-PCR analysis. For microarray hybridizations, 5µg of total RNA were directly labeled by reverse transcription and then purified using the Direct ShipShot Labeling kit (Promega). This reaction was performed for each of the 24 gonad samples, with Cy5 (red) incorporation. The reference sample was Cy3-labeled (green) in 24 separate tubes following the same protocol. The 24 Cy3-labeled cDNAs were next pooled, and then divided once more into 24 samples to obtain a homogeneous reference. Equimolar amounts of cDNA samples and cDNA reference labeled with Cy5 and Cy3, respectively, were SpeedVac evaporated and mixed into a single pool with the hybridization buffer (ChipHyb™ hybridization buffer, Ventana Discovery, Tucson, AZ, USA). They were then co-hybridized on the same microarray slide, in a Ventana hybridization station (Ventana Discovery, Tucson, AZ, USA). The data submitted here correspond to the mean of the three replicates for each line and each date, representing 8 samples : gonad_resistant_date1 gonad_sensitive_date1 gonad_resistant_date2 gonad_sensitive_date2 gonad_resistant_date3 gonad_sensitive_date3 gonad_resistant_date4 gonad_sensitive_date4
2009-08-15 | E-GEOD-16448 | biostudies-arrayexpress
Project description:The cultivated Pacific oyster Crassostrea gigas has suffered for decades large scale summer mortality phenomenon resulting from the interaction between the environment parameters, the oyster physiological and/or genetic status and the presence of pathogenic microorganisms including Vibrio species. To obtain a general picture of the molecular mechanisms implicated in C. gigas immune responsiveness to circumvent Vibrio infections, we have developed the first deep sequencing study of the transcriptome of hemocytes, the immunocompetent cells. Using Digital Gene Expression (DGE), we generated a transcript catalog of up-regulated genes from oysters surviving infection with virulent Vibrio strains (Vibrio splendidus LGP32 and V. aestuarianus LPi 02/41) compared to an avirulent one, V. tasmaniensis LMG 20012(T). For that an original experimental infection protocol was developed in which only animals that were able to survive infections were considered for the DGE approach. We report the identification of cellular and immune functions that characterize the oyster capability to survive pathogenic Vibrio infections. Functional annotations highlight genes related to signal transduction of immune response, cell adhesion and communication as well as cellular processes and defence mechanisms of phagocytosis, actin cytosqueleton reorganization, cell trafficking and autophagy, but also antioxidant and anti-apoptotic reactions. In addition, quantitative PCR analysis reveals the first identification of pathogen-specific signatures in oyster gene regulation, which opens the way for in depth molecular studies of oyster-pathogen interaction and pathogenesis. This work is a prerequisite for the identification of those physiological traits controlling oyster capacity to survive a Vibrio infection and, subsequently, for a better understanding of the phenomenon of summer mortality. 4 Samples.
2011-11-01 | E-GEOD-33390 | biostudies-arrayexpress
Project description:Marine intertidal organisms commonly face hypoxic stress during low tide emersion; moreover, eutrophic conditions and sediment nearness could lead to hypoxic phenomena; it is indeed important to understand the molecular processes involved in the response to hypoxia. In this study the molecular response of the Pacific oyster Crassostrea gigas to prolonged hypoxia (2 mg O2 L-1 for 20 d) was investigated under experimental conditions. A transcriptomic approach was employed using a cDNA microarray of 9058 C. gigas clones to highlight the genetic expression patterns of the Pacific oyster under hypoxic conditions. Lines of oysters resistant (R) and susceptible (S) to summer mortality were used in this study. This is the first study employing microarrays to characterize the genetic markers and metabolic pathways responding to hypoxic stress in C. gigas.
2010-09-01 | GSE23883 | GEO
Project description:The cultivated Pacific oyster Crassostrea gigas has suffered for decades large scale summer mortality phenomenon resulting from the interaction between the environment parameters, the oyster physiological and/or genetic status and the presence of pathogenic microorganisms including Vibrio species. To obtain a general picture of the molecular mechanisms implicated in C. gigas immune responsiveness to circumvent Vibrio infections, we have developed the first deep sequencing study of the transcriptome of hemocytes, the immunocompetent cells. Using Digital Gene Expression (DGE), we generated a transcript catalog of up-regulated genes from oysters surviving infection with virulent Vibrio strains (Vibrio splendidus LGP32 and V. aestuarianus LPi 02/41) compared to an avirulent one, V. tasmaniensis LMG 20012(T). For that an original experimental infection protocol was developed in which only animals that were able to survive infections were considered for the DGE approach. We report the identification of cellular and immune functions that characterize the oyster capability to survive pathogenic Vibrio infections. Functional annotations highlight genes related to signal transduction of immune response, cell adhesion and communication as well as cellular processes and defence mechanisms of phagocytosis, actin cytosqueleton reorganization, cell trafficking and autophagy, but also antioxidant and anti-apoptotic reactions. In addition, quantitative PCR analysis reveals the first identification of pathogen-specific signatures in oyster gene regulation, which opens the way for in depth molecular studies of oyster-pathogen interaction and pathogenesis. This work is a prerequisite for the identification of those physiological traits controlling oyster capacity to survive a Vibrio infection and, subsequently, for a better understanding of the phenomenon of summer mortality.
2011-11-01 | GSE33390 | GEO
Project description:Marine intertidal organisms commonly face hypoxic stress during low tide emersion; moreover, eutrophic conditions and sediment nearness could lead to hypoxic phenomena; it is indeed important to understand the molecular processes involved in the response to hypoxia. In this study the molecular response of the Pacific oyster Crassostrea gigas to prolonged hypoxia (2 mg O2 L-1 for 20 d) was investigated under experimental conditions. A transcriptomic approach was employed using a cDNA microarray of 9058 C. gigas clones to highlight the genetic expression patterns of the Pacific oyster under hypoxic conditions. Lines of oysters resistant (R) and susceptible (S) to summer mortality were used in this study. This is the first study employing microarrays to characterize the genetic markers and metabolic pathways responding to hypoxic stress in C. gigas. For the microarray analysis oysters were sampled at days 0, 2, 10, and 20 after the beginning of hypoxia. On each date, the digestive gland from 6 oysters was dissected, pooled, and stored at -80°C in Extract-All Reagent (Eurobio) at a concentration of 1 mL/50 mg tissue until total RNA was extracted. For each condition (hypoxia and normoxia) and oyster line (R and S), 4 pools were sampled (biological replicates) for a total of 56 pools during the 4 days of sampling. Furthermore, the entire tissue from 10 wild oysters was collected, pooled, and homogenized in Extract-all Reagent (Eurobio) to constitute a single total RNA sample to use as a reference in all slide hybridizations and Real-Time PCR analyses. Five ?g of total RNA were directly labeled by reverse transcription using the Direct ChipShot Direct Labeling and Clean-Up Kit (Promega). The samples were labeled with Cyanine-5 (Cy5). The reference samples were labeled with Cyanine-3 (Cy3) in separate tubes following the same protocol. The Cy3-labeled cDNAs were pooled and re-divided to obtain a homogeneous reference sample. cDNA samples and references were evaporated in a SpeedVac and mixed into a single pool in equimolar amounts with the Chip Hybe hybridization buffer (Ventana Discovery). Hybridization was performed using a Ventana automatic hybridization station (Ventana Discovery).
2010-09-01 | E-GEOD-23883 | biostudies-arrayexpress
Project description:This experiment was designed to enable the identification of field mortality sensitive Pacific oysters while also permitting the repetitive, non-lethal sampling of tissue from identifiable individual oysters. These samples have been difficult to obtain because pre-mortality phenotypes are obscured by the presence of an outer shell which occludes all views of body tissues. Additionally, mortality triggers have not been identified and there is need to better characterize the pathophysiology preceding mortality. 300 three year old oysters were sampled on 6 dates from May to October, 2008 from their grow out site at Totten Inlet, WA, USA. 100-200ul of hemolymph was withdrawn from the adductor muscle and preserved for possible mRNA analysis by microarray. At the end of the summer, mortality phenotypes were assigned to individuals (alive vs. dead/mortality). Gene expression profiles from screened mortality individuals showed up-regulation of a set of 124/11904 ESTs within one month of death that were not usually found in the alive individuals. This indicates that the path to death in oysters occurs over several days and maybe weeks, and is a molecularly coordinated response in which the hemolymph is involved. Gene expression predictors of survival fate could be developed from this data set.
2011-03-16 | E-MTAB-548 | biostudies-arrayexpress
Project description:To assess the diurnal gene expression in gills of oyster Crassotrea gigas, gills of 6 oysters were pooled and analyzed by RNa-seq every 4h for 52h (i.e. 13 sampling times). This procedure was executed simultaneously for control oysters fed with the non-harmful algae Heterocapsa triquetra (H.t condition), and for oysters fed with the harmful algae Alexandrium minutum (A.m condition) (L:D 9:15). Alexandrium minutum exposure led to a remodeling of the cycling transcriptome in gills of Crassostrea gigas.
2017-11-20 | E-MTAB-5345 | biostudies-arrayexpress
Project description:Low salinity is one of the main factors limiting the distribution and survival of marine species. As a euryhaline species, the Pacific oyster Crassostrea gigas can be tolerant to relative low salinity. Through Illumina sequencing, we generated two transcriptomes with samples taken from gills of oysters exposed to the low salinity seawater versus the optimal seawater. By RNAseq technology, we found 1665 up-regulation genes and 1815 down-regulation genes that may regulate osmotic stress in C. gigas. As blasted by GO annotation and KEGG pathway mapping, functional annotation of the genes recovered diverse biological functions and processes. The genes regulated significantly were dominated in cellular process and regulation of biological process, intracellular and cell, binding and protein binding according to GO annotation. The results highlight genes related to osmoregulation and signaling and interactions of osmotic stress response, anti-apoptotic reactions as well as immune response, cell adhesion and communication, cytosqueleton and cell cycle. The study aimed to compare the expression data of the two transcriptomes to provide some useful insights into signal transduction pathways in oysters and offer a number of candidate genes as potential markers of tolerance to hypoosmotic stress for oysters. In addition, the characterization of C. gigas transcriptome will facilitate research into biological processes underlying physiological adaptations to hypoosmotic shock for marine invertebrates. Twelve Pacific oysters were exposed in low salinity (8‰) seawater and in optimal salinity (25‰) seawater, respectively. Gills from six oysters in each condition were balanced mixed respectively. The transcriptomes of two samples were generated by deep sequencing, using Illumina HiSeq2000.
2012-12-15 | E-GEOD-38022 | biostudies-arrayexpress