不同因素对大肠杆菌转化效率的影响

The Study on Transformation Efficiency of Escherichia coli Affected by Different Factors

在质粒转化过程中存在很多对转化效率有影响的因素。本研究以转化操作中最常用的两种大肠杆菌菌株—BL21和DH5a为研究对象,对冰孵时间、热激时间、保存温度及保藏时间进行了深入研究,总结出获得最佳转化效率的条件。对于E. coli BL21,冰孵60 min、热激90s可以达到最大转化效率,并且在-20℃中保藏可以极大的增加转化效率。对于E. coli DH5a,冰孵30 min,热激120 s可以达到最大转化效率,在-4℃中保存1天就会下降一半,而在-20℃中保存则可以维持其转化效率。

There were numerous factors which can affect transformation efficiency in plasmid transformation process. In this study, we took two the most common strains of E.coli in transformation operation-BL21 and DH5 a as our study objects and obtained optimum transformation conditions through deep explorations of ice-incubation time, heat shock time, preservation temperature and time. The result showed that we can attain the maximum transformation efficiency when competent cells were ice-incubated 60 min and heat shocked 90 s towards E. coli BL21, and the efficiency of it will extremely enhance when competent cells were preserved in-20 ℃. What’s more, 30 min ice-incubation and 120 s heat shock were the conditions that bring the maximum transformation efficiency to DH5 a,and the efficiency could be sustained during preservation at-20 ℃, but sharply decline a half at 4 ℃.