Cloning and expression of cry11B gene from a local isolate of bacillus thuringiensis and its mosquitocidal activity

The present paper describes cry11b gene from a local isolate of bacillus thuringiensis (b.t.). escherichia coli dh5α was transformed with recombinant dna comprising ptz57 and b. t. cry11b gene (1.9kb) amplified from a local b.t. isolate sbs b.t. 48 for cloning. the cloned 1.9kb gene was sequenced and then ligated in the expression vector pt7-7 for transformation of e. coli bl2ic +. for expression of the recombinant organism containing cry11b gene,the conditions were optimized with respect to iptg concentration,time of induction and incubation temperature. the optimized expression was recorded at 1.0mm iptg incubated at 37°c for 3.5 h. the toxicity of b.t. spores,recombinant organisms and crude recombinant cry11b proteins was determined against the third instar larvae of mosquito,anopheles stephensi. the lc 50 of sbs b.t. 48 spores,recombinant organisms and recombinant cry11b protein was,respectively,700 μg /ml,525 μg/ml and 390 ng/ml as against 850,550 and 470 of hd500 standard b.t. strain. the toxicity of crude cry11b recombinant protein was 1346 fold higher than that of the recombinant organism. copyright 2011 zoological society of pakistan.