Toxic dinoflagellates (Alexandrium fundyense and A-catenella) have minimal apparent effects on oyster hemocytes
|Author(s)||Hegaret Hélène2, Wikfors Gary H.1, Soudant Philippe3, Lambert Christian3, Shumway Sandra E.2, Berard Jean-Baptiste4, Lassus Patrick4|
|Affiliation(s)||1 : NOAA Fisheries, NE Fisheries Sci Ctr, Milford, CT 06460 USA.
2 : Univ Connecticut, Marine Sci Dept, Groton, CT 06340 USA.
3 : IUEM UBO, LEMAR, UMR 6539, Plouzane, France.
4 : IFREMER, F-44311 Nantes, France.
|Source||Marine Biology (0025-3162) (Springer), 2007-08 , Vol. 152 , N. 2 , P. 441-447|
|WOS© Times Cited||54|
|Abstract||The possible effect of Alexandrium spp. containing paralytic shellfish poisoning (PSP) toxins on the hemocytes of oysters was tested experimentally. In one trial, eastern oysters, Crassostrea virginica Gmelin, were exposed to bloom concentrations of the sympatric dinoflagellate, Alexandrium fundyense Balech, alone and in a mixture with a non-toxic diatom, Thalassiosira weissflogii (Grun) Fryxell et Hasle. Subsequently, another experiment exposed Pacific oysters, Crassostrea gigas Thunberg, to a mixed suspension of the sympatric, toxic species Alexandrium catenella (Whedon et Kofoid) Balech, with T. weissflogii. Measurements of numbers of oyster hemocytes, percentages of different cell types, and functions (phagocytosis, reactive oxygen species (ROS) production, and mortality) were made using flow-cytometry. During and after exposure, almost no significant effects of Alexandrium spp. upon hemocyte numbers, morphology, or functions were detected, despite observations of adductor-muscle paralysis in C. virginica and measured toxin accumulation in C. gigas. The only significant correlation found was between toxin accumulation at one temperature and higher numbers of circulating live and dead hemocytes in C. gigas. The PSP toxins are known to interfere specifically with sodium-channel function; therefore, the finding that the toxins had no effect on measured hemocyte functions suggests that sodium-channel physiology is not important in these hemocyte functions. Finally, because oysters were exposed to the living algae, not purified toxins, there was no evidence of bioactive compounds other than PSP toxins affecting hemocytes in the two species of Alexandrium studied.|