Larvicidal properties of the 42 and 51 kilodaltonBacillus sphaericus proteins expressed in different bacterial hosts: Evidence for a binary toxin

Abstract

The 51 kilodalton (kDa) and the 42 kDa larvicidal proteins ofBacillus sphaericus 2362 appear to reside on a single transcriptional unit. Constructs containing the genes for both of these proteins or for only the 51 kDa or the 42 kDa protein were inserted into the appropriate expression vectors and the proteins over-produced inEscherichia coli JM105, andBacillus sphaericus strain 718 and SSII-1. In all of these organisms the 51 kDa and 42 kDa proteins were not toxic alone but were toxic in combination. These results are interpreted to indicate that theBacillus sphaericus 2362 larvicide is a binary toxin in that both the 51 and the 42 kDa proteins are required for toxicity.