Effect of UV treatments on the activity of delta-endotoxin protein crystals in Bacillus thuringiensis [electronic resource].

Includes references.

The ability of some isolates of B.thuringiensis to produce dark brown pigment were measured as an indicator to UV resistant, Ms isolate was used as wild type to improve it to be more resistant to UV, upon. It exposed to UV irradiation with different periods, ranged between 1 to 10 hrs. The induced mutants were examined morphologically by phase contrast microscope. 144 mutants were obtained, ten ofthem were selected and tested for their toxicity against Spodoptera littorallis. The results showed that mutants 62, 64 and 85 were the most toxic ones. These three mutants and wild type were examined by transmission electron microscope. Crystal proteins, with bipyramidial shape and active against Lepidoptera insects, were detected in all the selected mutants.

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