Golubkov V I, Gupalova T V, Iontova I M, Kolesnichenko T G, Totolian A A
Mol Biol (Mosk). 1977 Jul-Aug;11(4):909-16.
DNA of the streptococcal plasmid ERLI, determining resistance to erythromycin and lincomycin has been studied. The presence of satellite DNA component in streptococcal DNA has been demonstrated by dye-CsCl and CsCl density centrifugation, by chromatography of denatured-renatured DNA on the nitrocellulose and by electron microscopy. By all these methods the presence of covalently closed circular DNA molecules has been shown. Plasmid DNA has buoyant density in CsCl equal to 1.698 g/cm3 (GC content--38.8%), molecular weight (by electron microscopy) -- 19.8 Mdal; number of copies chromosomal genome equivalent is equal to about 4--4.5. Plasmid ERLI DNA was extracted from an original strain-carrier of plasmid ERLI, from a transduced strain which received plasmid ERLI as a result of transduction and lysogenization by phage "mo" and from the two antibiotic sensitive EMS mutants of resistant strain. Satellite DNA could not be isolated from a sensitive strain which served as a recipient in transduction experiments. The results obtained are in agreement with the literature on the molecular weight of the plasmid measured by the sedimentation analysis and with the previous genetic data on the antibiotic resistance within group A streptococci.
对决定对红霉素和林可霉素耐药性的链球菌质粒ERLI的DNA进行了研究。通过染料 - CsCl和CsCl密度离心、变性 - 复性DNA在硝酸纤维素上的色谱分析以及电子显微镜观察，证实了链球菌DNA中卫星DNA成分的存在。通过所有这些方法都显示了共价闭合环状DNA分子的存在。质粒DNA在CsCl中的浮力密度等于1.698 g/cm³（GC含量 - 38.8%），分子量（通过电子显微镜） - 19.8 Mdal；染色体基因组当量的拷贝数约为4 - 4.5。质粒ERLI DNA是从质粒ERLI的原始菌株携带者、通过噬菌体“mo”转导和溶源化获得质粒ERLI的转导菌株以及耐药菌株的两个抗生素敏感EMS突变体中提取的。在转导实验中作为受体的敏感菌株无法分离出卫星DNA。获得的结果与通过沉降分析测量的质粒分子量的文献以及先前关于A组链球菌内抗生素耐药性的遗传数据一致。
