Separation of the toxin of Bacillus cereus into two components and nonidentity of the toxin with phospholipase.

Molnar, Dorothy M. (U.S. Army Chemical Corps, Fort Detrick, Frederick, Md.). Separation of the toxin of Bacillus cereus into two components and nonidentity of the toxin with phospholipase. J. Bacteriol. 84:147-153. 1962-Bacillus cereus produced toxin in a Casamino acids medium without added serum or other protein. The toxin was separated into two components by adsorption on columns of calcium phosphate gel followed by elution with phosphate buffer (pH 7.5). The component eluted first has been called factor I and the component eluted later factor II. When tested alone each component was relatively nontoxic, but when combined they formed a toxic mixture as evidenced by skin reactions in guinea pigs and tests for lethal effects in mice. The phospholipase activity, determined by the egg-yolk reaction, was found in the fraction containing factor I. However, using columns of alumina-C(gamma) gel the phospholipase activity was found in the fraction containing factor II. This suggests that the phospholipase is not the same chemical entity as either factor I or II. The following are further evidence for the non-identity of the toxin and phospholipase: (i) differential precipitation of the two activities by (NH(4))(2)SO(4); (ii) differential neutralization by various antisera; and (iii) differential inhibition with ethanol.