title: Integrative study of physiological changes associated with bacterial infection in Pacific oyster larvae.
abstract: BACKGROUND
  Bacterial infections are common in bivalve larvae and can lead to significant mortality, notably in hatcheries. Numerous studies have identified the pathogenic bacteria involved in such mortalities, but physiological changes associated with pathogen exposure at larval stage are still poorly understood. In the present study, we used an integrative approach including physiological, enzymatic, biochemical, and molecular analyses to investigate changes in energy metabolism, lipid remodelling, cellular stress, and immune status of Crassostrea gigas larvae subjected to experimental infection with the pathogenic bacteria Vibrio coralliilyticus.
  
  
  RESULTS
  Our results showed that V. coralliilyticus exposure induced (1) limited but significant increase of larvae mortality compared with controls, (2) declined feeding activity, which resulted in energy status changes (i.e. reserve consumption, β-oxidation, decline of metabolic rate), (3) fatty acid remodeling of polar lipids (changes in phosphatidylinositol and lysophosphatidylcholine composition`, non-methylene-interrupted fatty acids accumulation, lower content of major C20 polyunsaturated fatty acids as well as activation of desaturases, phospholipase and lipoxygenase), (4) activation of antioxidant defenses (catalase, superoxide dismutase, peroxiredoxin) and cytoprotective processes (heat shock protein 70, pernin), and (5) activation of the immune response (non-self recognition, NF-κκ signaling pathway, haematopoiesis, eiconosoids and lysophosphatidyl acid synthesis, inhibitor of metalloproteinase and antimicrobial peptides).
  
  
  CONCLUSIONS
  Overall, our results allowed us to propose an integrative view of changes induced by a bacterial infection in Pacific oyster larvae, opening new perspectives on the response of marine bivalve larvae to infections.
authors.affiliation: Institut des sciences de la mer, Université du Québec à Rimouski, Rimouski, Québec, Canada. bertrand.genard@uqar.qc.ca
authors.forename: Bertrand
authors.initials: B
authors.lastname: Genard
authors.forename: Philippe
authors.initials: P
authors.lastname: Miner
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Nicolas
authors.forename: Dario
authors.initials: D
authors.lastname: Moraga
authors.forename: Pierre
authors.initials: P
authors.lastname: Boudry
authors.forename: Fabrice
authors.initials: F
authors.lastname: Pernet
authors.forename: Réjean
authors.initials: R
authors.lastname: Tremblay
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000382:microbiology* / Q000503:physiopathology*; D049896:Crassostrea / Q000235:genetics / Q000382:microbiology* / Q000502:physiology*; D058645:Denaturing Gradient Gel Electrophoresis; D004734:Energy Metabolism; D007814:Larva / Q000382:microbiology / Q000502:physiology; D008954:Models, Biological; D018384:Oxidative Stress; D010140:Pacific Ocean; D016019:Survival Analysis; D014733:Vibrio / Q000502:physiology*