Takahashi S, Nagano Y
Medical Microbiology Laboratory, Funabashi Medical Center, Chiba, Japan.
J Clin Microbiol. 1988 Feb;26(2):244-9. doi: 10.1128/jcm.26.2.244-249.1988.
We developed a novel method whereby the digestion pattern of each plasmid was distinguished in a sample of endonuclease-digested plasmid DNAs which contained multiple plasmids extracted from a bacterial strain. This method consisted of two procedures. (i) The concentration ratio of each undigested plasmid DNA and of each digested DNA fragment was calculated on the basis of densitometric scanning of an electrophoretogram, and the concentration ratio was then compared with the theoretical concentration ratio to determine from which plasmid each fragment was generated. (ii) The second procedure involved rapid visual identification with a scanning graph. We thus analyzed five strains of Escherichia coli that harbored several cryptic plasmids. The two procedures made it possible to analyze the restriction digestion pattern of each plasmid without the need to isolate the individual plasmids, except in the case of certain fragments. Even when the digested patterns of these exceptional fragments could not be distinguished completely, however, our method had the advantage that peak patterns of plasmids could be compared visually among different bacterial strains.
我们开发了一种新方法，可在含有从细菌菌株中提取的多个质粒的核酸内切酶消化质粒DNA样本中区分每个质粒的消化模式。该方法包括两个步骤。（i）根据电泳图的光密度扫描计算每个未消化质粒DNA和每个消化DNA片段的浓度比，然后将该浓度比与理论浓度比进行比较，以确定每个片段是从哪个质粒产生的。（ii）第二步涉及用扫描图进行快速目视鉴定。因此，我们分析了携带几种隐蔽质粒的五株大肠杆菌。这两个步骤使得无需分离单个质粒（某些片段除外）就可以分析每个质粒的限制性消化模式。然而，即使这些特殊片段的消化模式不能完全区分，我们的方法仍具有可在不同细菌菌株之间直观比较质粒峰模式的优点。
