Biochemical and immunological characterization of the cloned crystal toxin of Bacillus thuringiensis var. israelensis.

The protein components of the cloned crystal toxin of Bacillus thuringiensis var. israelensis were separated by polyacrylamide gel electrophoresis under denaturing conditions. Using an antiserum to the solubilized B. thuringiensis var. israelensis crystal protein as a probe, immunological homology between the crystal protein components of B. thuringiensis var. israelensis and those of the recombinant B. megaterium strain VB131 was tested. The results from this study indicate that the crystal inclusion of the recombinant strain contains only the 130 kilodalton protein and not the 68 or the 28 kilodalton proteins of the crystal toxin of B. thuringiensis var. israelensis and that the 130 kilodalton protein is primarily responsible for the mosquitocidal activity of this organism.