Hadley R G, Deonier R C
J Bacteriol. 1979 Sep;139(3):961-76. doi: 10.1128/jb.139.3.961-976.1979.
Eight new F' plasmids derived from Hfr strains in which F is integrated at the chromosomal element alpha 3 beta 3 have been isolated and subjected to restriction enzyme, hybridization, and electron microscope heteroduplex analysis. Plasmids carrying extensive amounts of bacterial deoxyribonucleic acid were produced even though they were obtained by selection for transfer of lac, which is closely linked to F in the parental Hfr strains. Seven plasmids were type II Flac+ proC+ purE+ plasmids, and one was a type I Flac+ proC+ plasmid. Five of the Flac+ proC+ purE+ plasmids contain approximately 284 kilobases of bacterial deoxyribonucleic acid, which is identical for all five within the resolution of the restriction enzyme analysis. Theses results indicate that type II F' plasmids are the predominant tra+ F' type from this region of the Escherichia coli K-12 chromosome and that the recombination events leading to formation of these plasmids exhibit site specificity.
从F整合于染色体元件α3β3的Hfr菌株中分离出了8种新的F'质粒，并对其进行了限制性内切酶、杂交和电子显微镜异源双链分析。尽管这些质粒是通过选择lac（在亲本Hfr菌株中与F紧密连锁）的转移而获得的，但仍产生了携带大量细菌脱氧核糖核酸的质粒。7种质粒是II型Flac+ proC+ purE+质粒，1种是I型Flac+ proC+质粒。5种Flac+ proC+ purE+质粒含有约284千碱基的细菌脱氧核糖核酸，在限制性内切酶分析的分辨率范围内，这5种质粒的该区域是相同的。这些结果表明，II型F'质粒是来自大肠杆菌K-12染色体该区域的主要tra+ F'类型，并且导致这些质粒形成的重组事件表现出位点特异性。
