10.3 Chemiluminescent responses of Ostrea edulis and Crassostrea gigas hemocytes to Bonamia ostreae (Ascetospora)

SUMMARYThis study investigated the ability of the Pacific oyster, Crassostrea gigas, to act as a carrier or reservoir of the protistan Bonamia ostreae. Studies were carried out independently in Ireland and in Spain. Naïve C. gigas were exposed to B. ostreae both in the field and in the laboratory via natural exposure or experimental injection. Naïve flat oysters, Ostrea edulis, were placed in tanks with previously exposed C. gigas. Oysters were screened for B. ostreae by examination of ventricular heart smears and by polymerase chain reaction (PCR) screening of tissue samples (gill and/or heart) and shell cavity fluid. PCR-positive oysters were further screened using histology and in situ hybridization (ISH). B. ostreae DNA was detected in the tissues and/or shell cavity fluid of a small number of C. gigas in the field and in the laboratory. B. ostreae-like cells were visualized in the haemocytes of 1 C. gigas and B. ostreae-like cells were observed extracellularly in the connective tissues of 1 other C. gigas. When C. gigas naturally exposed to B. ostreae were held with naïve O. edulis, B. ostreae DNA was detected in O. edulis; however, B. ostreae cells were not visualized. In Spain, B. exitiosa DNA was also detected in Pacific oyster tissues. The results of this study have important implications for C. gigas transfers from B. ostreae-endemic areas to uninfected areas and highlight B. ostreae and B. exitiosa's ability to survive extracellularly and in other non-typical hosts.

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Interactions between Bonamia ostreae (Protozoa: Ascetospora) and hemocytes of Ostrea edulis and Crassostrea gigas (Mollusca: Bivalvia): Entry mechanisms

Journal of Invertebrate Pathology ◽

10.1016/0022-2011(92)90128-q ◽

1992 ◽

Vol 59 (3) ◽

pp. 241-249 ◽

Cited By ~ 41

Author(s):

D. Chagot ◽

V. Boulo ◽

D. Hervio ◽

E. Mialhe ◽

E. Bachere ◽

...

Keyword(s):

Crassostrea Gigas ◽

Ostrea Edulis ◽

Bonamia Ostreae

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Some biochemical and physiological aspects of growth and gametogenesis inCrassostrea gigasandOstrea edulisgrown at sustained elevated temperatures

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400046208 ◽

1979 ◽

Vol 59 (1) ◽

pp. 95-110 ◽

Cited By ~ 190

Author(s):

Roger Mann

Keyword(s):

Crassostrea Gigas ◽

Elevated Temperatures ◽

Excretion Rate ◽

Ammonia Excretion ◽

Live Weight ◽

Gonadal Development ◽

Ostrea Edulis ◽

Shell Weight ◽

Histological Assessment ◽

Ammonia Excretion Rate

Crassostrea gigas (Thunberg) andOstrea edulis L.were grown at sustained temperatures of 12°, 15°, 18° and 21°C for a period of 19 weeks. Regular assays of weight specific ammonia excretion rate were made, following which animals were sacrificed for estimation of dry meat weight, dry shell weight, biochemical composition (percentage carbon, nitrogen, carbohydrate, ash) and gonadal development (histological assessment). Crassostrea gigas grew from an intial live weight of 5·2 g to values of 23·5, 28·2, 34·6 and 38·7 g at 120, 150, 180 and 21 °C respectively.

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A non-lethal method for detection of Bonamia ostreae in flat oyster (Ostrea edulis) using environmental DNA

Scientific Reports ◽

10.1038/s41598-020-72715-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Louise von Gersdorff Jørgensen ◽

Johan Wedel Nielsen ◽

Mikkel Kehler Villadsen ◽

Bent Vismann ◽

Sussie Dalvin ◽

...

Keyword(s):

Water Samples ◽

Sea Water ◽

Diagnostic Technique ◽

Environmental Dna ◽

Detection Methods ◽

Ostrea Edulis ◽

Breeding Programs ◽

Bonamia Ostreae ◽

Flat Oyster ◽

Selection Of

Abstract Surveillance and diagnosis of parasitic Bonamia ostreae infections in flat oysters (Ostrea edulis) are prerequisites for protection and management of wild populations. In addition, reliable and non-lethal detection methods are required for selection of healthy brood oysters in aquaculture productions. Here we present a non-lethal diagnostic technique based on environmental DNA (eDNA) from water samples and demonstrate applications in laboratory trials. Forty oysters originating from Limfjorden, Denmark were kept in 30 ppt sea water in individual tanks. Water was sampled 6 days later, after which all oysters were euthanized and examined for infection, applying PCR. Four oysters (10%) were found to be infected with B. ostreae in gill and mantle tissue. eDNA purified from the water surrounding these oysters contained parasite DNA. A subsequent sampling from the field encompassed 20 oysters and 15 water samples from 5 different locations. Only one oyster turned out positive and all water samples proved negative for B. ostreae eDNA. With this new method B. ostreae may be detected by only sampling water from the environment of isolated oysters or isolated oyster populations. This non-lethal diagnostic eDNA method could have potential for future surveys and oyster breeding programs aiming at producing disease-free oysters.

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