Water soluble toxins of bacillus thuringiensis serotype H-14 demonstrating lethal action on culex pipiens larvae

ABSTRACT

The lethal action of Bacillus thuringiensis on mosquito larvae was studied, in relation to the exotoxin proteins secreted during the vegetative growth. The water soluble protein fractions [exotoxins] were separated through gel filtration and polyacrylamide gel electrophoresis and bioassayed against 3 rd instar larvae of culex pipiens. Five fractions were detected in 72 hr bacterial cultures. Results of bioassays indicate toxicity of 3 protein subfarctions of M. Wts [31.000, 32.700 and 36.700 dalton]. Other types of detectedd proteins were found non -toxic. Based on the achieved results the exotoxins may be considered in larvicids formulations of Bacillus thuringiensis H -14