pH对苏云金杆菌晶体致病性的影响

报道了以苏云金杆菌5个菌株的晶体，经粘虫和黄粉虫幼虫的肠液在pH为6．4、7，4、8．4和9．4的缓冲液中（28℃）消化6小时后，其上清液（消化部分）和沉淀（未消化部分）对三龄末粘虫和黄粉虫幼虫的毒力。结果表明，457株、HD－1珠和10－4－13株的上清波和沉淀对粘虫均有不同程度的毒效，T84-1，株和T2株的上清液和沉淀对粘虫均无毒效；而对黄粉虫幼虫，以pH9．4时的上清液和沉淀均无毒效，在pH6．4和7．4时晶体被消化得极少，pH8．4时能被消化但较pH9．4时少。证明了pH对晶体的消化起重要作用，也表明了晶体之间在结构上存在着差异。

The influence of pH on the pathogenicity of crystals of Bacillus thuringiensis Berliner

The crystals of five strains of Bacillus ihuringiensis were digested with gut juice of armyworm and mealworm larvae in the buffer solutions of pH 6.4, 7.4, 8.4 and 9.4 incubating in 280℃ for 6 hours. The toxicity of supernate and precipitate from above treatments to 3 instar armyworm and mealworm larvae were tested. The results showed that both of supeinates and precipitates of strains 457, HD- 1 and 10-4-13 had different degree toxticity to armyworm larvae but for mealworm larvae was no effect. The crystal of T84-1 and T2 two strains were not digested in gut juice of these two insects. Tests demonsirated that pH played an important role in digeste crystals and also revealed that crystal stru cture of different strains are not the same.