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

Binding of purified Bacillus sphaericus binary toxin and its deletion derivatives to Culex quinquefasciatus gut: elucidation of functional binding domains

“…At the time it was believed that the regional binding pattern of the FITC-labelled toxin was solely due to the action of the 42 kDa protein (Davidson, 1988). However recent studies have shown that the 42 kDa protein preparations used were contaminated with lower-molecular-mass derivatives of the the 5 1 kDa protein (Broadwell et al, 1990b;Davidson et al, 1990, Baumann et al, 1991 so that the reported binding patterns of the FITC-labelled proteins were due to a mixture of the 51 and 42 kDa proteins. In this work, we have separately cloned, expressed and purified the 51 and 42 kDa proteins as well as their NH2-and COOHterminal deletion derivatives.…”

“…The surviving larvae were counted after Binding of B. sphaericus toxin to mosquito gut 1519 24 h. Previous results showed that maximum toxicity occurred when the 51 and 42 kDa proteins were present in approximately equal concentrations (Broadwell et al, 1990b;Davidson et al, 1990). Based on this observation, the bioassays were designed such that the 51 kDa protein and its deletion derivatives were fed to the larvae in the presence of an equivalent concentration of 42 kDa protein and vice versa.…”

“…The position and sizes (kDa) of molecular weight markers are indicated in lane 1. larvicidal proteins may act as a binary toxin (Broadwell et al, 1990b;Davidson et al, 1990). Similarly, the deletion derivatives of P51 and P42 when fed alone to larvae were not toxic.…”

Mosquitocidal bacterial toxins: diversity, mode of action and resistance phenomena

“…Genes encoding binary toxin of highly toxic strains are grouped in four types. Several studies have shown that, when produced in Escherichia coli, both BinA and BinB are required for toxicity to mosquito larvae and that an equimolar ratio of both proteins yields the greatest toxicity (Broadwell et al 1990). It is interesting to note however, that the 42kDa (BinA) produced alone in recombinant B. thuringiensis is toxic to mosquitoes .…”

Characterization and biological activity of a brazilian isolate of Bacillus sphaericus (Neide) highly toxic to mosquito larvae

“…As it is demonstrated graphically the pattern of toxicity is very similar in all mosquito species tested. The 51 and 42 kDa toxic proteins reported elsewhere (Baumann et al 1988, Broadwell et al 1990, were visualized in SDS-PAGE of the alkali extracts from all primary powders. Elution of proteins from slab polyacrylamide gels onto nitrocellulose membranes, and further exposure to the 42 kDa antiserum, confirmed the presence of that peptide in crude extracts from both S2 or 2362 strains (Fig.…”