球孢白僵菌胞外蛋白酶和几丁质酶活性与对亚洲玉米螟毒力的相关性分析

以振荡摇瓶培养法培养17株球孢白僵菌(Beauveria bassiana),分析其总胞外蛋白酶和几丁质酶的产生水平,同时用这些菌株的分生孢子粉作为样品,用人工饲养的亚洲玉米螟5 d龄幼虫作为试虫,作毒力生物测定.并分析各个因素之间的相关性,验证各个酶活性指标作为毒力的生物测定的替代或者补充指标的可能性.结果表明,菌株间同代毒力、酶活之间的差异比较大,LT50的变化范围为4.82～10.06 d,胞外蛋白酶活性的变化范围是0.86×10-2～3.66×10-2 IU/mL,胞外几丁质酶活性的变化范围是0.012～1.47 IU/mL.将后二者分别与各个菌株对玉米螟的LT50进行回归分析,结果发现胞外蛋白酶活性和胞外几丁质酶活性以及测定胞外蛋白酶活性时的干物质增重3个指标,与感染的亚洲玉米螟幼虫的死亡率及LT50的相关性都不显著,不能作为对亚洲玉米螟毒力的生物测定的替代或补充指标.

Short mucin 1 alleles are associated with low virulent H pylori strains infection

TO THE EDITORWe read with interest the article published by Nguyen et al in the World Journal of Gastroenterology, showing an association between short MUC6 alleles and H pjloff infection. These results, together with previous observations by Vinall et al, reinforce the role of mucin genes （MUC6 and MUC1） VNTR polymorphisms for the variability in individual susceptibility to H pylori infection that cannot be explained by differences in environmental factors.