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根据Bacillussphaericus2362二元毒素基因核着酸序列合成的一组寡聚核苷酸为引物，通过PCR扩增出1．1kb的DNA片段作探针检测了C3-41、IAB881、IAB872、BS－197和LP1－G菌株中二元毒素基因。Southern杂交表明C3-41、IAB881、IAB872和BS－197菌株中3·5kbHindⅢ及LP1-G中4.7kbHindⅢ的酶切片段分别带有与探针有高度同源性的二元毒素基因。SDS－PAGE和Western印迹杂交表明所有菌株都能产生41．9kD和51．4kD的毒素蛋白。C3－41、IAB881、BS－197和2362的全发酵液和碱抽提液对敏感尖音库蚊Culexpipienssubsp．pipiens幼虫毒性高，但对抗性幼虫几乎无毒；LP1－G对敏感和抗性蚊幼虫具有相同的中度毒杀作用；IAB872对敏感幼虫毒性高，对抗性幼虫的毒力同LP1－G相似。这两株菌对抗性蚊幼虫的毒性可能是由Mtx毒素蛋白所导致的。
A group of oligonucleotides synthesized based on the nucleotide sequence of Bacilluphaphaphaerusus2362 binary toxin gene were used as primers to amplify the 1.1kb DNA fragment as a probe to detect C3-41, IAB881, IAB872, BS-197 and Binary toxin genes in LP1-G strains. Southern hybridization showed that the 4.7 kb HindIII digested fragments of 3.5 kb Hind III and LP1-G in C3-41, IAB881, IAB872 and BS-197 strains, respectively, carry the binary toxin gene with high homology to the probe. Hybridization by SDS-PAGE and Western blotting indicated that all strains produced 41.9 kD and 51.4 kD of toxin protein. C3-41, IAB881, BS-197 and 2362 of the whole fermentation broth and alkali extract of Culex pipienssubsp. The pipiens larvae are highly toxic, but almost nontoxic to the confronting larvae; LP1-G has the same moderate toxin killing effect on susceptible and resistant mosquito larvae; IAB872 is highly toxic to susceptible larvae and the virulence of the antagonistic larvae is similar to LP1-G . The toxicity of these two strains to mosquito-resistant mosquito larvae may be caused by the Mtx toxin protein.