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质粒自1959年在肠杆菌科细菌中发现转移性的R质粒(耐药质粒)以来,人们越来越重视从分子水平研究抗菌药物耐药性的发生和传播。为详尽地研究耐药质粒的发生和传播,需检测大量从医院分离的临床菌株中的质粒DNA。这种技术直到新近才成为可行,即通过在快速抽提过程中,小心控制碱浓度的分离沉淀方法。Birnboim和Doly(1979)所描述的一个最简便的方法,可在3小时内,利用价值约1500英镑的设备,从1.5ml肉汤培养菌液中抽提出质粒DNA。这个方法能抽提出大部分质粒,但分子量特别大或特别小的质粒不易分离出。因此需要采取其他抽提方法如密度梯度离心等研究细
Plasmids Since the discovery of metastatic R plasmids (enteric plasmids) in Enterobacteriaceae in 1959, there has been a growing emphasis on the development and spread of antimicrobial resistance at the molecular level. To study in detail the occurrence and spread of drug-resistant plasmids, a large number of plasmid DNA in clinical isolates isolated from hospitals were tested. This technique has not been possible until recently, ie by means of a separate precipitation method which carefully controls the alkali concentration during rapid extraction. One of the easiest ways, described by Birnboim and Doly (1979), is to extract plasmid DNA from 1.5 ml of broth culture in less than 3 hours using equipment worth about £ 1,500. This method extracts most of the plasmids, but plasmids with particularly large or extremely small molecular weights are not easily separated. Therefore need to take other extraction methods such as density gradient centrifugation and other research details