Expressão heteróloga da toxina Cry 11Aa de Bacillus thuringiensis (Berliner, 1919) var. israelensis em Escherichia coli (Escherich, 1885), visando o controle biológico

Abstract

Bacillus thuringiensis (Bt) is a Gram-positive bacteria, ubiquitous, facultative anaerobic, and form spores. During sporulation produce a parasporal crystals inclusion. Within these inclusions there are δ-endotoxin proteins well known for its insecticides proprieties. Among them, the Cry (crystal) is wide employed for biological control of plagues. The δ-endotoxin has an advantage of been more specific than chemical insecticides, thus been consider more favorable for the environment. The aim of this study was to obtain the Cry 11Aa recombinant protein of Bacillus thuringiensis var. israelensis in Escherichia coli, active for use in biocontrol. Two expression E. coli strains were tested: BL 21 (DE3) C41 and BL 21 (DE3) Ril. The protein Cry 11Aa was expressed and secreted in a soluble form by the two strains. The expression was demonstrated by Western Blot using anti-histidin monoclonal antibody. The strain BL 21 (DE3) C41 express the protein Cry 11Aa ~3.6 times more than the strain Rill, and showed a biologic efficiency of 95% of mortality for Culex quinquefaciatus larvae. The data obtained in this study suggest that the protein recombinant Cry 11Aa expressed in E. coli has a potential to be used in biological control.