【摘要】 目的 :确立一个能制备高转化率感受态细胞并长期维持其感受性的实验方案。方法 :比较CaCl2 法、TSS法、超高效法制备感受态细胞的效果 ,选用三者中较好的方法进一步探讨不同生长期 (OD值 0 .2～ 1.1)的细菌对制备感受态细胞的影响 ,并分别比较了不同冷冻保护剂 (7%DMSO ,10 %甘油 )于 - 2 0℃、- 80℃冰箱保存感受态细胞的效果。结果 :三种方法获得的感受态细胞转化率差异极显著 (P <0 .0 1)。采用超高效法 ,OD值为 0 .36 (或 0 .5 8)时收集菌体可获得 1.1× 10 8的高转化率的感受态细胞 ,以 7%的DMSO为冷冻保护剂保存感受态细胞可维持 10 7以上的转化率 4 0d以上更多还原

【Abstract】 Objective:To establishing a high efficient protocol for preparation and storage of competent Escherichia coli cells.Methods:Three methods（SEM,TSS and CaCl₂ method） were compared for preparation of competent cells;Escherichia coli at different growth stages(optical density range from A₆₀₀=0.2 to 1.1) were choosed for preparation of competent cells bythe best method,meanwhile different conditions were used for storage of competent cells.Results:High transformation efficiency can be achieved by SEM at A₆₀₀ of 0.36 or 0.58;cells stored with dimethylsulfoxide in -80℃ could keep consistently high transformation efficiency at least 40d.更多还原