Data/hora: 01/06/2024 04:54:14

Provedor de dados: | 5
País: | France
Título: | Etude des intéractions entre le parasite Bonamia ostreae et son hôte, huître plate Ostrea edulis in vitro
Autores: | Morga, Benjamin; Arzul, Isabelle; Chollet, Bruno; Gagnaire, Beatrice; Renault, Tristan.
Data: | 2007-05-29
Ano: | 2007
Palavras-chave: | Hémocytes; Ostrea edulis; Bonamia ostreae; Parasite; Huîtres.
Resumo: | Bonamiosis is a disease affecting the flat oyster Ostrea edulis and caused by the protozoa parasite Bonamia ostreae, which is affiliated to the haplosporidia order and the cercozoa phylum. This parasite is mainly intracellular, infecting haemocytes, circulating cells playing an important role in the oyster's defence mechanisms. Even though the parasite's cycle has not been completely understood yet, direct infection from infected oysters to healthy oysters is possible. This leads us to think that there is no intermediary host in the cycle. Very little data on the parasite's infection mechanisms or the host's defence mechanisms is available. In order to better comprehend the Bonamia ostreae / host interaction, some flat oyster's haemocytes have been put in contact with purified parasites from strongly infected individuals and with purified parasites inactivated by a heat treatment (100°C during 15 minutes). Two parasite concentrations were tested (5 and 10 parasites for 1 haemocyte). Isolated haemocytes were used as controls for all measures. Haemocyte parameters were analysed, after two hours of contact, in flow cytometry and light microscopy. The "contact" experiment was carried out three times and in three replicates. The different haemocyte activities measured in flow cytometry were cell mortality, non-specific esterase activities, free radicals production and phagocytic activity. Moreover, haemocytes that had been put in contact with the parasite were observed with a light microscope after cytocentrifugation and hemacolor kit (Merck&amp;#61666;) colouring. Results show a significant drop of esterase activity in the parasited haemocytes (active or inactive) as well as an inhibition of the free radical production. This inhibition seems to vary according to the amount of parasites put in contact with the haemocytes. On the other hand, no significant action of the parasite on the phagocytic activity after two hours in contact has been demonstrated. Microscope observations confirm the flow cytometry results. These results help us understand the different mechanisms developed by the parasite to "escape" the haemocyte degradation following phagocytosis, but they have to be completed by a kinetic study of the haemocyte activities after contact with the parasite.
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/2007/acte-3368.pdf
Editor: | 45ème Colloque du GPLF (Groupement des Protistologues de Langue Française)
Relação: | http://archimer.ifremer.fr/doc/00000/3368/
Formato: | application/pdf