SEPARATION AND CHARACTERIZATION OF ENTEROTOXIN AND TWO HAEMOLYSINS FROM AEROMONAS HYDROPHILA

Abstract

Aeromonas hydrophila produces two haemolysins, now designated α- and β-haemolysin (formerly aerolysin or cytotoxic protein), and one enterotoxin. These toxins were separated and purified by isoelectric focusing and gel chromatography. Alpha- and β-haemolysin differ with regard to prerequisites for their elaboration, such as selection of A. hydrophila strains and temperature and time for cultivation. The nature of their lytic effects on erythrocytes toxic effects on tissue culture cells differs significantly. Alpha- but not β-haemolysin was inactivated by reducing agents and activated by oxygen, while β-haemolysin was more resistant than α-haemolysin to proteolytic enzymes but was inactivated by crude gangliosides. When separated from the two haemolysins, the enterotoxin gave positive reactions in the rabbit intestinal loop test, the rabbit skin and the adrenal Yl cell test, though the sensitivity of the Y1 cell was low as compared with cholera toxin and E. coli LT toxin. No cytotoxic effects were obtained in HeLa cells.