Comparison of the activities of Bacillus thuringiensis mosquitocidal crystal proteins on mosquito cell lines (Diptera, Culicidae), using two colorimetric methods

Two colorimetric methods were compared for assaying the cell toxicity of so luble crystal proteins from five mosquitocidal serovarieties of Bacillus th uringiensis: israelensis, jegathesan, medellin, darmstadiensis and fukuokae nsis. In mosquitoes cell lines from Culex quinquefasciatus, Aedes aegypti a nd Anopheles gambiae, all the crystal proteins were equally toxic. Both col orimetric methods MTT (tetrazolium salt) and Alamar Blue gave similar resul ts, but the Alamar Blue method was simpler, faster, cheaper, and could be u sed to take readings from the same cell population at various time points. The most active crystal proteins were those of B. thuringiensis israelensis , followed by those of B. thuringiensis jegathesan, and B. thuringiensis me dellin, which were much less active.