Wild female Crassostrea corteziensis oyster (n=245) were analyzed over one year to understand the main ecophysiological events associated to gonad development. Different indicators (mainly biochemical) were analyzed to infer: i) utilization and accumulation of energy reserves (e.g.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
September 2011
In a previous study, dietary supplementation with arachidonic acid (ARA) to oysters Crassostrea gigas increased haemocyte numbers, phagocytosis, and production of reactive oxygen species level (ROS) by haemocytes (Delaporte et al., 2006). To assess if the observed stimulation of these cellular responses resulted from changes of ARA-related prostaglandin (PG) production, we analysed prostaglandin E2 metabolite (PGEM) content on the same oysters fed three levels of ARA.
View Article and Find Full Text PDFThe effects of an artificial bloom of the toxin-producing dinoflagellate, Alexandrium minutum, upon physiological parameters of the Pacific oyster, Crassostrea gigas, were assessed. Diploid and triploid oysters were exposed to cultured A. minutum and compared to control diploid and triploid oysters fed T.
View Article and Find Full Text PDFSummer 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 cDNA microarray that we designed.
View Article and Find Full Text PDFBackground: Although bivalves are among the most-studied marine organisms because of their ecological role and economic importance, very little information is available on the genome sequences of oyster species. This report documents three large-scale cDNA sequencing projects for the Pacific oyster Crassostrea gigas initiated to provide a large number of expressed sequence tags that were subsequently compiled in a publicly accessible database. This resource allowed for the identification of a large number of transcripts and provides valuable information for ongoing investigations of tissue-specific and stimulus-dependant gene expression patterns.
View Article and Find Full Text PDFThe generation of EST information is an essential step in the genomic characterisation of species. In the context of the European Network Marine Genomics, a common goal was to significantly increase the amount of ESTs in commercial marine mollusk species and more specifically in the less studied but ecologically and commercially important groups, such as mussel and clam genera. Normalized cDNA libraries were constructed for four different relevant bivalves species (Crassostrea gigas, Mytilus edulis, Ruditapes decussatus and Bathymodiolus azoricus), using numerous tissues and physiological conditions.
View Article and Find Full Text PDFThe response of Crassostrea gigas to prolonged hypoxia was investigated for the first time by analyzing the metabolic branch point formed by pyruvate kinase (PK) and hosphoenolpyruvate carboxykinase (PEPCK). PK and PEPCK cDNAs were cloned and sequenced. The main functional domains of the PK sequence, such as the binding sites for ADP/ATP and phosphoenolpyruvate (PEP), were identified whereas the PEPCK sequence showed the specific domain to bind PEP in addition to the kinase-1 and kinase-2 motifs to bind guanosine triphosphate (GTP) and Mg(2+), specific for all PEPCKs.
View Article and Find Full Text PDFArachidonic acid (20:4n-6, ArA) and its eicosanoid metabolites have been demonstrated to be implicated in immune functions of vertebrates, fish, and insects. Thus, the aim of this study was to assess the impact of ArA supplementation on the FA composition and hemocyte parameters of oysters Crassostrea gigas. Oyster dietary conditioning consisted of direct addition of ArA solutions at a dose of 0, 0.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
April 2005
The impact of diets upon the fatty acid composition of haemocyte polar lipids and consequently upon immune parameters has been tested in the oyster Crassostrea gigas and the clam Ruditapes philippinarum. Oysters and clams were fed each of three cultured algae: Chaetoceros calcitrans, which is rich in 20:5(n-3) and 20:4(n-6) and poor in 22:6(n-3) fatty acids; T-Iso (Isochrysis sp.), which is rich in 22:6(n-3) and deficient in 20:5(n-3) and 20:4(n-6); and Tetraselmis suecica, which is deficient in 22:6(n-3) and contains only small amounts of 20:5(n-3) and 20:4(n-6).
View Article and Find Full Text PDF