Characterization of Mosquito Larvicidal <i>Bacillus thuringiensis </i>Isolated from Soils of India

Abstract

It has been established now that insects are acquiring resistance to commercial products of <i>Bacillus thuringiensis. </i>So there is a continuous search for bacteria producing new toxins. With this in view, an insecticidal <i>B. thuringiensis </i>was isolated from soil sample obtained from the vicinity of a penicillin factory in Vadodara, India. The isolate belongs to serotype H-14. Phenotypic characters of the isolate were identical to standard <i>B. thuringiensis </i>var. <i>israelensis </i>IPS-82. It was found to possess good larvicidal activity against <i>Anopheles stephensi </i>and <i>Culex pipiens </i>and exhibited high resistance for penicillin

(500 ug/ml), The electrophoretic protein profiles of purified crystals with standard <i>B. thuringiensis </i>(IPS-82) were studied. The isolate apparently showed the same protein profile as that of <i>B. thuringiensis </i>var. <i>israelensis. </i>Soil with natural selective pressure of antibiotic penicillin thus appears to be a good ecological niche for the isolation of <i>B. thuringiensis.</i>