ACID-PHOSPHATASE-ACTIVITY IN PERKINSUS-MARINUS, THE PROTISTAN PARASITE OF THE AMERICAN OYSTER, CRASSOSTREA-VIRGINICA

The effect of temperature (4, 12, 20, and 28 C) and osmolality (400, 5 70, and 840 mOsm/kg) on extracellular acid phosphatase (AP) secretion in vitro, and ultrastructural localization of AP activity in the paras ite were investigated. The extracellular AP secretion by Perkinsus mar inus was cell density dependent (P < 0.001). Increasing culture temper atures resulted in increased P. marinus proliferation concomitant with AP secretion (P < 0.0001). AP secretion was similar in P. marinus cul tured at 400 and 570 mOsm/kg media, but higher than P. marinus culture d at 870 mOsm/kg media. Results of the ultrastructural study revealed that intense AP activity was in the nucleus of the parasite. Based on its distribution in the nucleus, AP may be playing a role in events le ading to cell cycle regulation.