Israelensis recombinants , which contained recombinants plasmid pmt4 and pmt9 respectively , were obtained by electroporation . the bioassay results showed that the recombinants b - pmt9 and b - pmt4 had toxicities both to resistant and susceptible c . quinqnefasciatus larvae during vegetative growth stage , having the lc ? o values similar to that of . fi . sssii - 1 . however , the toxic levels of the final sporulated cultures of recombinants b - pmt4 and b - pmt9 differed , with a lcso value of 2 49mg / ml for b - pmt9 and little toxicity for b - pmt4 by using the plasmid pmt9 , m txl gene from b . sphaericus was ligated with p20 and cytjaa gene , giving recombinant plasmid pmpx2 含有pmt9和pmt4的大肠杆菌转化子能表达产生mtx1毒素，发酵液对敏感和抗性致倦库蚊幼虫具有中度毒杀作用；含有pmt9和pmt4的苏云金芽孢杆菌转化子b - pmt9和b - pmt4在营养体生长阶段对敏感蚊幼和抗性幼虫也具有毒性，毒力与野生型b . sss - 1相当，而不同转化子在芽孢形成期的毒力因插入的mtx1基因转录方向不同而表现出差异，其中b - pmt4对目标蚊幼毒力极低( lc _ ( 50 ) 10mg ml ) ，而b - pmt9对蚊幼虫具有毒性( lc _ ( 50 ) = 2 . 49mg ml ) 。
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