Parisi J T, Robbins J, Lampson B C, Hecht D W
J Bacteriol. 1981 Nov;148(2):559-64. doi: 10.1128/jb.148.2.559-564.1981.
A strain of Staphylococcus epidermidis was transduced to erythromycin resistance, and all of the transductants exhibited the macrolide, lincosamide, streptogramin B resistance phenotype. Curing and antibiotic disk studies also indicated that these resistances were controlled by a single plasmid determinant and were constitutive. Agarose gel electrophoresis of plasmid deoxyribonucleic acid (DNA) from donor, cured, and transduced strains showed that a single plasmid was responsible. This plasmid, designated pNE131, was examined for sequence homology to two other plasmids, pE194 and p1258, from Staphylococcus aureus, which also code for erythromycin resistance. DNA from plasmids pNE131 and pE194 hybridized with one another, but no extensive homology to pI258 with either pNE131 or pE194 was found. Restriction endonuclease digests of pNE131 and pE194 showed no common fragments. However, sequence homology was localized to the nucleotides in pE194 that code for the 29,000-dalton protein responsible for erythromycin resistance. pNE131 was calculated to have 2,220 base pairs and is the smallest naturally occurring plasmid with a known function yet reported in S. epidermidis.
一株表皮葡萄球菌被转导获得红霉素抗性，所有转导子均表现出大环内酯、林可酰胺、链阳菌素B抗性表型。消除实验和抗生素纸片扩散法研究还表明，这些抗性由单一质粒决定因子控制且呈组成型。对供体、消除后的菌株及转导菌株的质粒脱氧核糖核酸（DNA）进行琼脂糖凝胶电泳，结果显示单一质粒起作用。该质粒命名为pNE131，检测其与金黄色葡萄球菌的另外两个也编码红霉素抗性的质粒pE194和pI258的序列同源性。质粒pNE131和pE194的DNA彼此杂交，但未发现pNE131或pE194与pI258有广泛同源性。pNE131和pE194的限制性内切酶消化产物未显示共同片段。然而，序列同源性定位于pE194中编码负责红霉素抗性的29000道尔顿蛋白的核苷酸。pNE131经计算有2220个碱基对，是表皮葡萄球菌中已报道的具有已知功能的最小天然质粒。
