Department of Epidemiology and Clinical Microbiology, National Medicines Institute, Warsaw, Poland.
Pol J Microbiol. 2010;59(2):79-87.
Pheromone-responsive plasmids constitute a unique group of approximately 20 plasmids identified, as yet, only among enterococcal species. Several of their representatives, e.g. pAD1, pCF10, pPD1 and pAM373 have been extensively studied. These plasmids possess a sophisticated conjugation mechanism based on response to sex pheromones--small peptides produced by plasmid-free recipient cells. Detailed analysis of regulation and function of the pheromone response process revealed its great complexity and dual role--in plasmid conjugation and modulation of enterococcal virulence. Among other functional modules identified in pheromone plasmids, the stabilization/partition systems play a crucial role in stable maintenance of the plasmid molecule in host bacteria. Among them, the par locus of pAD1 is one of the exceptional RNA addiction systems. Pheromone-responsive plasmids contribute also to enterococcal phenotype being an important vehicle of antibiotic resistance in this genus. Both types of acquired vancomycin resistance determinants, vanA and vanB, as well many other resistant phenotypes, were found to be located on these plasmids. They also encode two basic agents of enterococcal virulence, i.e. aggregation substance (AS) and cytolysin. AS participates in mating-pair formation during conjugation but can also facilitate the adherence ofenterococci to human tissues during infection. The second protein, cytolysin, displays hemolytic activity and helps to invade eukaryotic cells. There are still many aspects of the nature of pheromone plasmids that remain unclear and more detailed studies are needed to understand their uniqueness and complexity.
信息素响应质粒构成了一个独特的群体，目前仅在肠球菌种中发现了大约 20 种此类质粒。其中一些代表性的质粒，如 pAD1、pCF10、pPD1 和 pAM373，已经得到了广泛的研究。这些质粒拥有一种复杂的基于对性信息素（质粒缺失的受体细胞产生的小肽）响应的 conjugation 机制。对信息素响应过程的调控和功能的详细分析揭示了其复杂性和双重作用——既参与质粒的 conjugation，又调节肠球菌的毒力。在信息素质粒中鉴定出的其他功能模块中，稳定/分配系统在质粒分子在宿主细菌中的稳定维持中起着关键作用。在 pAD1 的 par 基因座中，存在一种特殊的 RNA 成瘾系统。信息素响应质粒也有助于肠球菌的表型，是该属中抗生素耐药性的重要载体。两种类型的获得性万古霉素耐药决定簇，vanA 和 vanB，以及许多其他耐药表型，都被发现位于这些质粒上。它们还编码两种肠球菌毒力的基本因子，即聚集物质（AS）和细胞溶解素。AS 参与 conjugation 过程中的配对形成，但也可以促进肠球菌在感染过程中与人组织的黏附。第二种蛋白质细胞溶解素具有溶血活性，有助于侵入真核细胞。信息素质粒的性质仍有许多方面尚不清楚，需要进行更详细的研究以了解其独特性和复杂性。
