耐盐细菌质粒的研究

本实验以1株耐盐细菌My23（耐18％NaCl）作为研究对象，采用碱裂解法对其进行质粒提取，结果表明可以提取得大小2个不同质粒；改变常规提取方法中的部分环节，如加入STE清洗菌体的培养基成分，溶菌酶的使用，以及加入碱裂解液Ⅰ后静置20min，对该耐盐菌质粒的提取有较好的作用。经SDS法将小质粒消除后的菌株与野生型菌株的耐盐功能比较，发现提取出的小质粒与耐盐无关。将大肠杆菌DH5α制备成感受态细胞，将耐盐菌的质粒进行转化，结果进一步表明耐盐性状与质粒没有关系。

Study on Plasmids of Halotolerant Bacteria

In this experiment, a halotolerant bacteria Hy23 which can grow in LB medium containing 18% NaCl was studied and could be extracted two different sizes of plasmids by alkaline lysis method. Changing some segments of alkaline lysis method, such as using STE to wash the cells, treating with lysozyme and placing 20min after Solution Ⅰ, played a better role in extracting plasmids. By comparison of salt tolerance of the plasmid - cured strain by SDS and the wild type, it could be found that salt tolerance of Hy23 had nothing to do with the small plasmid extracted. The plasmids of strain Hy23 was transformed and E. coli DH5α was the competent cell. The results of transformation further demonstrated that salt - tolerant traits of Hy23 had no relationship with the small plasmid.