Analysis of expression of the binary toxin genes from Bacillus sphaericus in Anabaena and the potential in mosquito control

Anabaena strains expressing the binary toxin genes of Bacillus sphaericus p roduce high larvicidal activity with living cells. Western blot analysis sh owed that the 51-kDa and 42-kDa toxin proteins were stable in Anabaena. Whe n a DNA fragment upstream of the 51-kDa protein gene was deleted, the toxic ity was reduced by over a hundred-fold, whereas deletions at the coding reg ions showed that the cooperation of the two proteins expressed in Anabaena is essential for the larvicidal activity. Outdoor tests showed that the gen etically altered Anabaena could keep containers with natural water from bei ng inhabited by Culex larvae for over 2 months.