HEMOLYTIC PROPERTIES OF HEMOCYANIN FROM MUD CRAB SCYLLA SERRATA

Recently, infectious diseases have seriously inhibited the aquaculture of mud crab Scylla serrata in southeastern China. A better understanding of the immune molecules and defense mechanisms may be beneficial in reducing the harmful nature of these diseases. Available data show that hemocyanin (H MC) is a copper-containing respiratory protein present in the hemolymph of both mollusc and arthropod, and that it plays multiple roles in immune defense. In the current study, 14 MC from S. serrata (HMC-C) was isolated, and its hemolytic properties were investigated. The HMC-C shows hemolytic activities against vertebrate erythrocytes. The hemolysis displays dependency on pH, temperature, divalent cation, and HMC-C concentration. Complete hemolysis occurred at a concentration of 0.1 mg/mL, pH 5.0, and temperature of 37 degrees C in the presence of calcium. Furthermore, all 5 subunits of HMC-C were detected in the solubilized incubation products of erythrocytes with HMC-C, and the hemolysis could be inhibited to different degrees by osmoprotectants of various molecular masses. Together, our data suggest that HMC-C mediates hemolysis by inserting all 5 subunits into the erythrocyte membrane, causing cell rupture through a colloid osmotic mechanism.