Optimization of Condition for Preparation of Competent Cells of Methylase-deficiency E. coli with High Transformation Efficiency

Objective To optimize the condition for preparation of competent cells of methylase-deficiency E.coli DM1 with high transformation efficiency.Methods The effect of growth state of E.coli DM1,time for ice bath,time for heat shock and resuscitation time after transformation on transformation efficiency were observed,based on which the condition for preparation of competent cells was optimized.Results The transformation efficiency of competent cells prepared with E.coli DM1 at A600 of 0.39 and 0.69 kept in ice bath for 30 min and incubated at 42℃ for 90 s for heat shock was satisfactory.However,the resuscitation time after transformation showed no significant effect on transformation efficiency.Conclusion The condition for preparation of competent cells of methylase-deficiency E.coli DM1 with high transformation efficiency was optimized,which met most of the requirements for routine cloning in plasmids.