RESUMEN
Bonamiosis due to the parasite Bonamia ostreae has been associated with massive mortality in flat oyster stocks in Europe. Control of the disease currently relies on disease management practices and transfer restriction. Previously, massal selections based on survival to challenge to infection with B. ostreae have been applied to produce flat oyster families with resistant progeny. In an attempt to understand the molecular mechanisms involved in disease resistance, differentially expressed sequence tags between resistant and wild Ostrea edulis haemocytes, both infected with the parasite, were identified using suppression subtractive hybridisation. Expression of seven ESTs has been studied using quantitative reverse-transcriptase PCR. The base-line expression of an extracellular superoxide dismutase, inhibitor of apoptosis (OeIAP), Fas ligand (OeFas-ligand) and Cathepsin B was significantly increased, whilst cyclophilin B appeared significantly decreased in resistant oysters. Considering their great interest for further studies, the open reading frames of the OeFas-ligand and OeIAP were completely sequenced.
Asunto(s)
Resistencia a la Enfermedad , Haplosporidios/fisiología , Ostrea/genética , Ostrea/parasitología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Resistencia a la Enfermedad/genética , Etiquetas de Secuencia Expresada , Proteína Ligando Fas/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Hemocitos/parasitología , Interacciones Huésped-Parásitos , Proteínas Inhibidoras de la Apoptosis/genética , Datos de Secuencia Molecular , Ostrea/clasificación , Ostrea/inmunología , Filogenia , Alineación de SecuenciaRESUMEN
Virus-induced genes were identified using suppression subtractive hybridisation (SSH) from Pacific cupped oyster, Crassostrea gigas, haemocytes challenged by OsHV-1. A total of 304 clones from SSH forward library were sequenced. Among these sequences, some homologues corresponded to (i) immune related genes (macrophage express protein, IK cytokine, interferon-induced protein 44 or multicopper oxidase), (ii) apoptosis related genes (Bcl-2) and (iii) cell signalling and virus receptor genes (glypican). Molecular characterization and phylogenic analysis of 3 immune-related genes (macrophage expressed protein, multicopper oxidase and immunoglobulin domain cell adhesion molecule) were performed. Finally, quantitative PCR revealed significant changes in the expression of immune related genes (multicopper oxidase, macrophage expressed protein, myeloid differentiation factor 88 and interferon-induced protein 44) in oysters experimentally challenged with OsHV-1. These findings provide a first basis for studying the role of innate immunity in response to viruses in bivalves and identified genes may serve as markers of interest in breeding programs in order to obtain selected oysters presenting OsHV-1 resistance.
Asunto(s)
Crassostrea/genética , Infecciones por Herpesviridae/inmunología , Herpesviridae/inmunología , Animales , Apoptosis/genética , Crassostrea/inmunología , Crassostrea/virología , Citocinas/genética , Citocinas/metabolismo , Perfilación de la Expresión Génica , Glipicanos/genética , Glipicanos/metabolismo , Herpesviridae/patogenicidad , Inmunidad Innata/genética , Filogenia , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Transducción de Señal/genéticaRESUMEN
Polyphasic analysis of four new Vibrio isolates originating from the haemolymph of diseased cultured oysters is described. The new isolates were closely related to Vibrio splendidus, having 98 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on DNA gyrase subunit B (gyrB), RNA polymerase sigma70 factor (rpoD), replication origin-binding protein (rctB) and transmembrane regulatory protein (toxR) genes, fluorescent amplified fragment length polymorphism and DNA-DNA hybridization experiments clearly showed that the new isolates form a tight genomic group that is different from the currently known Vibrio species. It is proposed that these new isolates should be accommodated in a novel species, Vibrio gigantis sp. nov. Phenotypic features that differentiate V. gigantis from other known Vibrio species include arginine dihydrolase, gelatinase and beta-galactosidase activities, NO(2) production, growth at 35 degrees C, and utilization of sucrose, melibiose, amygdalin, glycerol, galactose, starch and glycogen. The type strain is LGP 13T (=LMG 22741T=CIP 108656T).
Asunto(s)
Crassostrea/microbiología , Girasa de ADN/genética , Vibrio/clasificación , Animales , ADN Bacteriano/análisis , ADN Bacteriano/química , Filogenia , ARN Ribosómico 16S/análisis , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Vibrio/aislamiento & purificaciónRESUMEN
Polyphasic analysis of five new Vibrio isolates originating from the haemolymph of diseased cultured oysters is described. The new isolates were closely related to Vibrio splendidus, having 98 % 16S rRNA gene sequence similarity. gyrB phylogenetic analysis, fluorescent amplified-fragment length polymorphism (FAFLP) fingerprinting and DNA-DNA hybridization experiments clearly showed that the new isolates form a tight genomic group that is different from the currently known Vibrio species. It is proposed to accommodate these isolates in a novel species, Vibrio crassostreae sp. nov. (type strain LGP 7(T)=LMG 22240(T)=CIP 108327(T)). Phenotypic and chemotaxonomic features that differentiate V. crassostreae from other known Vibrio species include arginine dihydrolase, utilization and fermentation of various carbon sources, beta-galactosidase activity, NO(2) production and the presence of the fatty acids 14 : 0 iso and 16 : 0 iso.