Production and charactization of toxins of bacillus cereus and its mutants

ABSTRACT

The crude toxin from three standard Bacillus cereus strains [NRRL 569, ATCC 11778 and KllS] was found to contain hemolysin, phospholipase C and mouse lethality factor. Mutant 88 which results from U.V. induction to the type strain B. cereus NRRL 569 could not produce hemolysin in its crude toxin[s]; it also failed in causing lethality to mice. Mutants 318, 431 and 486 failed in producing phospholipase C in their crude toxins. Gamma irradiation has not obvious effect on the properties of the crude toxin [s] up to 20 kGy. The most suitable temperature for storage of B. cereus crude toxin [s] was found to be 4 deg. Mouse lethal toxin was found to be inactivated by heat treatment/denaturation at 65C for 5 minutes