Acid phosphatase in the pathogenic and nonpathogenic hemoflagellates, Cryptobia spp., of fishes

Acid phosphatase (ACP) was detected in whole-cell lysates, membrane-bound and water-soluble fractions of Cryptobia salmositica (pathogenic and nonpathogenic vaccine strains), Cryptobia bullocki, and Cryptobia catostomi using p-nitro-phenylphosphate as the substrate. High activities were in acidic pH (3.0-5.5) and the optimal pH was 5.0 Highest ACP activity was in the membrane-bound fraction. The pathogenic strain of C. salmositica had significantly higher total ACP activity than the vaccine strain and the other 2 species. However, the activity in the pathogenic C. salmositica decreased significantly with prolonged in vitro cultivation. The membrane-bound ACP of the pathogenic C. salmositica had highest resistance to the ACP inhibitor, sodium tartrate.