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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060
EISSN: 1678-8060
Vol. 107, No. 1, 2012, pp. 74-79
Bioline Code: oc12010
Full paper language: English
Document type: Research Article
Document available free of charge

Memórias do Instituto Oswaldo Cruz, Vol. 107, No. 1, 2012, pp. 74-79

 en Treatment of an Aedes aegypti check for this species in other resources colony with the Cry11Aa toxin for 54 generations results in the development of resistance
Cadavid-Restrepo, Gloria; Sahaza, Jorge & Orduz, Sergio

Abstract

To study the potential for the emergence of resistance in Aedes aegypti check for this species in other resources populations, a wild colony was subjected to selective pressure with Cry11Aa, one of four endotoxins that compose the Bacillus thuringiensis check for this species in other resources serovar israelensis toxin. This bacterium is the base component of the most important biopesticide used in the control of mosquitoes worldwide. After 54 generations of selection, significant resistance levels were observed. At the beginning of the selection experiment, the half lethal concentration was 26.3 ng/mL and had risen to 345.6 ng/mL by generation 54. The highest rate of resistance, 13.1, was detected in the 54th generation. Because digestive proteases play a key role in the processing and activation of B. thuringiensis toxin, we analysed the involvement of insect gut proteases in resistance to the Cry11Aa B. thuringiensis serovar israelensis toxin. The protease activity from larval gut extracts from the Cry11Aa resistant population was lower than that of the B. thuringiensis serovar israelensis susceptible colony. We suggest that differences in protoxin proteolysis could contribute to the resistance of this Ae. aegypti colony.

Keywords
Bacillus thuringiensis - Aedes aegypti - Cry11Aa toxin resistance - midgut proteases

 
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