Coykendall A L
J Bacteriol. 1971 Apr;106(1):192-6. doi: 10.1128/jb.106.1.192-196.1971.
The genetic homogeneity among eight cariogenic strains of Streptococcus mutans was assessed by deoxyribonucleic acid (DNA)-DNA reassociation experiments. DNA species were extracted from strains GS5, Ingbritt, 10449, FAl, BHT, E49, SLl, and KlR. Labeled DNA ((14)C-DNA) was extracted from strains 10449, FAl, and SLl. Denatured (14)C-DNA fragments were allowed to reassociate, i.e., form hybrid duplexes, with denatured DNA immobilized on membrane filters incubated in 0.45 m NaCl-0.045 m sodium citrate at 67 or 75 C. At 67 C, 10449 (14)C-DNA reassociated extensively only with GS5 and Ingbritt DNA. FAl (14)C-DNA hybridized extensively only with BHT DNA, and SLl (14)C-DNA reassociated with KlR and E49 DNA. DNA which hybridized extensively at 67 C also reassociated to a high degree at 75 C. Thermal elution of (14)C-FAl-BHT duplexes showed that the hybrid duplexes were thermostable. The results indicate that S. mutans is a genetically heterogeneous species. The strains studied can be divided into three (possibly four) genetic groups, and these groups closely parallel antigenic groups.
通过脱氧核糖核酸（DNA）-DNA重缔合实验评估了8株变形链球菌致龋菌株间的基因同质性。从GS5、Ingbritt、10449、FAl、BHT、E49、SLl和KlR菌株中提取DNA样本。从10449、FAl和SLl菌株中提取标记DNA（（14）C-DNA）。使变性的（14）C-DNA片段与固定在膜滤器上的变性DNA重缔合，即在0.45 m NaCl-0.045 m柠檬酸钠中于67或75℃孵育。在67℃时，10449（14）C-DNA仅与GS5和Ingbritt DNA广泛重缔合。FAl（14）C-DNA仅与BHT DNA广泛杂交，而SLl（14）C-DNA与KlR和E49 DNA重缔合。在67℃广泛杂交的DNA在75℃时也高度重缔合。（14）C-FAl-BHT双链体的热洗脱表明杂交双链体具有热稳定性。结果表明变形链球菌是一个基因异质的物种。所研究的菌株可分为三个（可能四个）基因群，且这些基因群与抗原群密切平行。
