Clewell D B, An F Y, White B A, Gawron-Burke C
J Bacteriol. 1985 Jun;162(3):1212-20. doi: 10.1128/jb.162.3.1212-1220.1985.
Streptococcus faecalis RC73 was found to harbor a conjugative plasmid (pAM373) which confers a mating response to a sex pheromone (cAM373) excreted by plasmid-free members of the same species. The pheromone was also detected in culture filtrates of all of 23 Staphylococcus aureus strains but in only 2 of 22 coagulase negative staphylococcus strains. Streptococcus sanguis Challis and G9B also produced the activity, but 10 other Streptococcus sanguis strains did not. The activity was also produced by Streptococcus faecium 9790. A tetracycline resistance (Tc) determinant present in S. faecalis RC73 was not associated with pAM373 but served as a useful marker in efforts to identify pAM373 among other plasmids present in the strain. Analyses of the Tc determinant showed that it was located on a conjugative transposon very similar to Tn916. Designated Tn918, the transposon could insert into pAM373 as well as into two other hemolysin plasmids. Whereas pAM373 derivatives transferred very well between strains of Streptococcus faecalis, the plasmid would not establish in Staphylococcus aureus or Streptococcus sanguis. However, a derivative of pAM373 carrying Tn918 proved to be a useful delivery vehicle for generating transposon insertions into multiple sites on the staphylococcal chromosome.
粪肠球菌RC73被发现携带一种接合质粒（pAM373），该质粒赋予对由同一物种无质粒成员分泌的性信息素（cAM373）的交配反应。在23株金黄色葡萄球菌的培养滤液中均检测到了该信息素，但在22株凝固酶阴性葡萄球菌中仅在2株中检测到。血链球菌Challis和G9B也产生了这种活性，但其他10株血链球菌没有。屎肠球菌9790也产生了这种活性。粪肠球菌RC73中存在的四环素抗性（Tc）决定簇与pAM373无关，但在鉴定该菌株中存在的其他质粒中的pAM373时可作为有用的标记。对Tc决定簇的分析表明，它位于一个与Tn916非常相似的接合转座子上。该转座子被命名为Tn918，它可以插入pAM373以及另外两个溶血素质粒中。虽然pAM373衍生物在粪肠球菌菌株之间转移得很好，但该质粒不能在金黄色葡萄球菌或血链球菌中稳定存在。然而，携带Tn918的pAM373衍生物被证明是一种有用的载体，可用于在葡萄球菌染色体的多个位点产生转座子插入。
