自生贝氏固氮菌的培养与DNA的提取

自生贝氏固氮菌的培养与DNA的提取 GROWTH OF FREE-AZOTOBACTERIA BEIJERINCKIA AND EXTSACT OF ITS DNA 黄永秀 first-author 余运萍 严家骐 采用常规的葡萄糖培养基（GM）培养自生贝氏固氮菌Beijerinckia SP.7号,细胞互相粘连成大的菌胶团,难以收获,不能破壁、溶菌,给DNA的提取带来极大困难。我们在GM培养基中加入SDS或以乳酸钠代替葡萄糖作碳源进行培养时,发现细胞分散,不形成菌胶团,容易离心回收,回收率提高5—7倍。以溶菌酶结合冻融法进行溶菌、破壁处理,原生质体形成率达到90%以上,DNA提取量提高数十倍,得到均一的DNA样品。该菌DNA的Tm值为89.6℃,GC含量为49.5%。 Using routine glucose medium（GM） to grow Azotobaeter beijerinckia Sp. 7（B. Sp.7）, bacreria cells stick together each other by mucoitin to become many big cysts tn this case. It is diffeculty to harvest cells, cytolysis and extract DNA from the cysts becouse of forming the cysts. When SDS was added in GM or sodium lactate was used to insteate of glucose as carbon sources, we discovered that growing cells disperse in the medium and do not forme cysts as without mucoitin outside cells. Thus rate of harvest cells increased also 5—7 folds. Forme of cytosomes is more then 90% and preperation of DNA increase tens times for cytolysis by combination of lysezyme and freese-thaw method. The DNA, which is one band on agarose gel, have a Tm of 89.6℃ and a GC of 49.5%. 1986-02-01 2021-04-01 2