An insect toxin from spores of Bacillus thuringiensis and Bacillus cereus.

Spores of Bacillus thuringiensis contain a toxin active against lepidopterous larvae. This toxin can be solubilized by extraction with reagents which dissolve the protein crystal of B thuringiensis. It is inactivated by crystal-specific antiserum. Spores of Bacillus cereus contain a similar toxin although the specific activity is much lower than the spores of B. thuringiensis. The B. cereus toxin contains a single major polypeptidecomponent. Toxic activity can be solubliized from spores of both species by incubation with gut juices from Pieris brassicae.