| 摘要 |
The invention relates to the discovery that nucleic acid sequences comprising a BtI or BtII promoter, or a combination of a BtI and a BtII promoter, a bacterial STAB-SD sequence, and a sequence encoding proteins of the B. sphaericus ("Bs") binary toxin and expressed in B. thuringiensis ("Bt") or Bs cells results in production of Bs binary toxin at least 10 times that of untransformed Bs cells. The invention provides nucleic acid sequences, expression vectors, host cells, and methods of increasing the toxicity of an insecticidal bacterium by transforming the bacterium with a nucleic acid sequence of the invention. Further, the invention relates to the discovery that the Cyt1Aa1 protein of Bt subspecies israelensis ("Bti") reverses resistance to Bs binary toxin in Bs-resistant mosquitoes. The invention provides Bs cells expressing Bti Cyt1Aa1 protein, and methods of reversing resistance to Bs binary toxin by co-administering the Cyt1Aa1 protein with Bs binary toxin.
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