ABSTRACT: The susceptibility of the eastern oyster Crassostrea virginica to infection by the protozoan parasite Perkinsus marinus is influenced by temperature. Because of the crucial roles of heat shock proteins in cellular thermal tolerance and in host-parasite adaptations in other species, we compared the in vitro heat shock responses of cultured P. marinus and of oyster hemocytes. The parasite and host heat shock proteins were different in size and in immunochemical specificity. In addition, the thermal threshold for inducing the response was higher for P. marinus acclimated to the same temperature as the oysters. The results suggest that P. marinus is likely to employ heat shock proteins as part of its adaptive survival repertoire and that it may be able to function normally under conditions of hyperthermia that evoke an emergency physiological response from the oyster defense cells. Furthermore, they indicate that it is feasible to investigate the host's and parasite's adaptive responses to each other, since their individual responses are readily distinguishable.

KEY WORDS: Parasite . Perkinsus marinus . Oysters . Crassostrea virginica . Hemocytes . Stress proteins . Hyperthermia

Published in DAO Vol. 22, No. 2 (1995) on June 15
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1995