绿色荧光蛋白穿梭载体的构建及其在嗜酸乳杆菌中的应用

Construction of the Shuttle Vector Expressing Green Fluorescent Protein and its Application in Lactobacillus acidophilus

为深入研究嗜酸乳杆菌的作用机理,以温敏型穿梭载体pSET4s为基本骨架,将绿色荧光蛋白(GFP)和嗜酸乳杆菌上、下游同源臂插入该载体,构建GFP标记的穿梭表达载体pSET4s-P1-GFP-P2。利用电转化方法将穿梭表达载体pSET4s-P1-GFP-P2转化入嗜酸乳杆菌,通过抗性和温度双重筛选获得能稳定表达GFP的重组嗜酸乳杆菌,将Western blotting和荧光显微镜观察验证的重组菌命名为ΔMG6243(GFP)。利用荧光显微镜观察和平板计数的方法对重组菌进行遗传稳定性和生物学特性研究。结果显示,重组菌在蓝光激发下可见明显绿色荧光,连传10代仍可见明显荧光,与野生菌相比,其生长特性、酸碱盐耐受性均无显著差别。结果表明,本试验已成功构建稳定表达GFP基因的重组嗜酸乳杆菌,利用温敏型穿梭载体pSET4s实现了外源基因在嗜酸乳杆菌中非抗性、整合型表达,为嗜酸乳杆菌基因重组菌的构建奠定了基础,同时GFP的标记作用也为嗜酸乳杆菌在动物体内分布、定植规律和作用机理创造了可行的条件。

In order to further study the mechanism of Lactobacillus acidophilus,GFP labeling shuttle expression vector pSET4s-P1-GFP-P2 was constructed by inserting green fluorescence protein（GFP）,upstream and downstream homology arm of Lactobacillus acidophilus based on temperature shuttle expression vector pSET4 s.Recombinant Lactobacillus acidophilus expressing green fluorescence gene was constructed by transforming pSET4s-P1-GFP-P2 into Lactobacillus acidophilus using electrotransformation.We could obtain the recombinant Lactobacillus acidophilus by resistance screening and temperature screening,and named it asΔMG6243（GFP）which could expressed GFP gene stably by fluorescence microscopy observation and Western blotting analysis.We could analyse the genetic stability and biological characteristics with fluorescence microscopy observation and plate count.Green fluorescent of recombinant Lactobacillus acidophilus could be observed in the blue light,and also be observed after 10 generations.There were significant differences neither growth characteristics nor pH and salt tolerance compared with the wildmushrooms.The results showed that GFP labeling recombinant Lactobacillus acidophilus was constructed successfully.Exogenous gene could be non-resistant and integrative to express in the Lactobacillus acidophilus with the vector.It established the foundation for construction of recombinant Lactobacillus acidophilus.At the same time,the role of the GFP as marker laid the foundation for distribution,adhesion of probiotic in animal gastrointestinal tract and the mechanism of Lactobacillus acidophilus.