MEI YUNJUN1, CHEN XIANGDONG2, XIE ZHIXIONG2, et al. Effect of Ca2+ on Forming Escherichia coli Competencce for Uptaking Exogenous DNA. [J]. 2012, 58(4): 354-358.
the exact point of Ca2+ exerting its function was determined according to the transformation efficiency.The result showed that the structure and physiology of cell were not changed perpetually and the capability of absorbing extracellular DNA was sustained only when the Ca2+ was present;the result also showed Ca2+ played an important role during the process of transformation
but whether E.coli was treated with Ca2+ or not and the duration of the treatment before the process did not cause obvious effect.