枯草芽孢杆菌蛋白酶np基因在苏云金芽孢杆菌BMB171中的表达

Expression of Protease np Gene of Bacillus subtilis in B. thuringiensis BMB171

为研究枯草芽孢杆菌(Bacillus subtilis)BLYS_1蛋白酶np基因在苏云金芽孢杆菌(B.thuringiensis)BMB171中的表达情况,从苏云金芽孢杆菌T6中克隆了cry3A启动子的两个片段,分别命名为pro3Aa和pro3Ab,并与pHT304质粒构建重组质粒pHT304-3Aa-np和pHT304-3Ab-np,分别转化苏云金芽孢杆菌BMB171,得到重组菌BLYS-3Aa-np和BLYS-3Ab-np。结果表明,重组菌BLYS-3Ab-np发酵液中约110 ku的蛋白酶条带亮度明显高于重组菌BLYS-3Aa-np发酵液中对应条带亮度,BLYS-3Ab-np产蛋白酶能力明显高于BLYS-3Aa-np,随着发酵时间延长到60 h,对应条带的亮度均比45 h条带弱,与发酵上清液中水解干酪素结果变化一致。

In order to study the expression of protease np gene of Bacillus subtilis in B.thuringiensis strain BMB171,two fragments of cry3A promoter were cloned and named as pro3Aa and pro3Ab.The two recombinant gene were inserted into shuttle vector pHT304,resulting two recombinant plasmid pHT304-3Aa-np and pHT304-3Ab-np.The recombinant plasmid were introduced into B.thuringiensis strain BMB171 respectively.The results showed that BLYS-3Ab-np had higher expression level of protease than BLYS-3Aa-np.With fermentation time extended to 60 h,the brightness of the bands were weaker than 45 h,consistent with fermentation supernatant hydrolyzed casein results.