The amphiphatic nature of Prymnesium parvum hemolysin

Abstract

1. 1. Prymnesium Toxin behaves as a surface-active agent and forms aggregates above the critical concentration of 0.6 ng/ml in isotonic NaCl solution. 2. 2. Factors affecting the critical micelle concentraion of surface-active agents, such as concentration, temperature and solvents were tested for their effect on the hemolytic activity. Above concentrations of 30 μg toxin/ml in methanol, the increment of hemolytic activity is much greater than the increment in the toxin concentration and they bear no fixed relation to one another. This effect can be reversed to prolonged incubation of the titrated toxin before addition of erythrocytes. After preincubation at −10 °C, aqueous or organic solutions of the toxin show a more than 20-fold increased activity. The cold activation is also reversible and disappears when the toxin is kept at 20 °C for 10 min before titration. 3. 3. The addition of organic solvents to an aqueous solution of the toxin considerably increases the hemolytic activity. 4. 4. The possibility that the toxin aggregates rather than the monomers are the active hemolysin is discussed.