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Abollo E.,Fundacion CETMAR Centro Tecnologico del Mar
Gene | Year: 2012

The European flat Ostrea edulis is highly susceptible to infection by the protozoan Bonamia ostreae and Bonamia exitiosa, intracellular parasites able to survive and proliferate within the oyster haemocytes. The parasite, once phagocytosed by the haemocyte, the main cellular effector of the immune system, appears to have some counter mechanism that turns off the haemocyte's metabolic destructive capacity, so that the parasite survives within the cell. To further understand the molecular basis of the immune response of the flat oyster against the bonamiosis, suppression subtractive hybridization and Q-PCR approaches were combined to identify genes involved in the development of the infection both in early and advanced phases. Four subtractive cDNA libraries were constructed and sequenced, obtaining a high number of ESTs that were seen to be up or down-regulated in the infection. A group of ESTs that play a role in the immune response, such as cytokines, stress proteins, eicosanoids, proteins implicated in phagocytosis and cell junction as well as in transcription signalling were identified and their expression was analysed at different infection levels by Q-PCR. The results here reported can help to enrich our understanding about the immune response of O. edulis against bonamiosis and improve our knowledge of the immune mechanisms of oysters. © 2011 Elsevier B.V. Source


Lynch S.A.,University College Cork | Abollo E.,Fundacion CETMAR Centro Tecnologico del Mar | Engelsma M.,Central Veterinary Institute of Wageningen UR | Stokes N.A.,Virginia Institute of Marine Science | Culloty S.C.,University College Cork
Journal of Invertebrate Pathology | Year: 2013

The phylum Haplosporidia is a group of obligate protozoan parasites that infect a number of freshwater and marine invertebrates. Haplosporidian parasites have caused significant mortalities in commercially important shellfish species worldwide. In this study, haplosporidia were detected in Pacific oysters Crassostrea gigas originating in Ireland and were subsequently identified independently in laboratories both in Ireland and in Spain as Haplosporidium nelsoni. In Ireland, H. nelsoni plasmodia were also observed in the heart tissue of a single Ostrea edulis. A range of techniques including heart smear screening, histology, standard polymerase chain reaction (PCR), direct sequencing and in situ hybridisation with an H. nelsoni specific DNA probe were carried out to confirm diagnosis. This is the first reporting of H. nelsoni in oysters in Ireland and this is the first reporting of the detection of this haplosporidian in O. edulis. In Ireland, another haplosporidian was also observed in a single O. edulis during heart smear screening. PCR and DNA sequencing were carried out and indicated the presence of a Haplosporidium sp., most likely Haplosporidium armoricanum. The low prevalence and intensity of infection of both haplosporidian species in Irish C. gigas and in particular O. edulis may indicate that their presence is inconsequential. © 2012 Elsevier Inc.. Source

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