Johnson S R, Anderson B E, Biddle J W, Perkins G H, DeWitt W E
Infect Immun. 1983 May;40(2):843-6. doi: 10.1128/iai.40.2.843-846.1983.
Three strains of Neisseria gonorrhoeae carried novel plasmids of 7.8 megadaltons (mdal) molecular mass in addition to plasmids previously observed in this organism. The presence of the 7.8-mdal plasmids was not accompanied by any distinguishable phenotype in the strain possessing them. Analysis of plasmid DNA with restriction endonucleases showed that these plasmids were composed of three directly repeated copies of a 2.6-mdal cryptic plasmid frequently found in N. gonorrhoeae. In addition, the 7.8-mdal plasmids exhibited characteristics common to the 2.6-mdal plasmid, structural lability and sites resistant to cleavage with HpaII. The concatemeric forms of the cryptic plasmid appear to be stable in these strains and do not undergo internal recombination to produce the 2.6-mdal monomer, nor were higher concatemers detected.
三株淋病奈瑟菌除了携带该菌先前已观察到的质粒外，还携带了分子量为7.8兆道尔顿（mdal）的新型质粒。在含有7.8-mdal质粒的菌株中，该质粒的存在并未伴随任何可区分的表型。用限制性内切酶分析质粒DNA表明，这些质粒由淋病奈瑟菌中常见的2.6-mdal隐蔽质粒的三个直接重复拷贝组成。此外，7.8-mdal质粒表现出2.6-mdal质粒共有的特征，即结构不稳定性和对HpaII切割有抗性的位点。隐蔽质粒的串联形式在这些菌株中似乎是稳定的，不会进行内部重组以产生2.6-mdal单体，也未检测到更高的串联体。
