Dower W J, Miller J F, Ragsdale C W
Molecular Biology Group, Bio-Rad Laboratories, Richmond, CA 94804.
Nucleic Acids Res. 1988 Jul 11;16(13):6127-45. doi: 10.1093/nar/16.13.6127.
E. coli can be transformed to extremely high efficiencies by subjecting a mixture of cells and DNA to brief but intense electrical fields of exponential decay waveform (electroporation). We have obtained 10(9) to 10(10) transformants/micrograms with strains LE392 and DH5 alpha, and plasmids pUC18 and pBR329. The process is highly dependent on two characteristics of the electrical pulse: the electric field strength and the pulse length (RC time constant). The frequency of transformation is a linear function of the DNA concentration over at least six orders of magnitude; and the efficiency of transformation is a function of the cell concentration. Most of the surviving cells are competent with up to 80% transformed at high DNA concentration. The mechanism does not appear to include binding of the DNA to the cells prior to entry. Possible mechanisms are discussed and a simple procedure for the practical use of this technique is presented.
通过使细胞与DNA的混合物经受指数衰减波形的短暂但强烈的电场（电穿孔），大肠杆菌可被转化至极高的效率。我们使用菌株LE392和DH5α以及质粒pUC18和pBR329已获得每微克10⁹至10¹⁰个转化体。该过程高度依赖于电脉冲的两个特性：电场强度和脉冲长度（RC时间常数）。转化频率是DNA浓度至少六个数量级范围内的线性函数；并且转化效率是细胞浓度的函数。大多数存活细胞具有感受态，在高DNA浓度下高达80%可被转化。该机制似乎不包括DNA在进入细胞之前与细胞的结合。文中讨论了可能的机制，并给出了该技术实际应用的简单程序。
