School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom.
J Bacteriol. 2010 Feb;192(4):1122-30. doi: 10.1128/JB.01293-09. Epub 2009 Dec 11.
To determine the relative importance of temperate bacteriophage in the horizontal gene transfer of fitness and virulence determinants of Enterococcus faecalis, a panel of 47 bacteremia isolates were treated with the inducing agents mitomycin C, norfloxacin, and UV radiation. Thirty-four phages were purified from culture supernatants and discriminated using pulsed-field gel electrophoresis (PFGE) and restriction mapping. From these analyses the genomes of eight representative phages were pyrosequenced, revealing four distinct groups of phages. Three groups of phages, PhiFL1 to 3, were found to be sequence related, with PhiFL1A to C and PhiFL2A and B sharing the greatest identity (87 to 88%), while PhiFL3A and B share 37 to 41% identity with PhiFL1 and 2. PhiFL4A shares 3 to 12% identity with the phages PhiFL1 to 3. The PhiFL3A and B phages possess a high DNA sequence identity with the morphogenesis and lysis modules of Lactococcus lactis subsp. cremoris prophages. Homologs of the Streptococcus mitis platelet binding phage tail proteins, PblA and PblB, are encoded on each sequenced E. faecalis phage. Few other phage genes encoding potential virulence functions were identified, and there was little evidence of carriage of lysogenic conversion genes distal to endolysin, as has been observed with genomes of many temperate phages from the opportunist pathogens Staphylococcus aureus and Streptococcus pyogenes. E. faecalis JH2-2 lysogens were generated using the eight phages, and these were examined for their relative fitness in Galleria mellonella. Several lysogens exhibited different effects upon survival of G. mellonella compared to their isogenic parent. The eight phages were tested for their ability to package host DNA, and three were shown to be very effective for generalized transduction of naive host cells of the laboratory strains OG1RF and JH2-2.
为了确定温带噬菌体在粪肠球菌（Enterococcus faecalis）适应度和毒力决定因素的水平基因转移中的相对重要性，对 47 株菌血症分离株用诱导剂丝裂霉素 C、诺氟沙星和紫外线进行处理。从培养上清液中纯化出 34 个噬菌体，并通过脉冲场凝胶电泳（PFGE）和限制图谱分析进行区分。通过这些分析，对 8 个代表性噬菌体的基因组进行了焦磷酸测序，揭示了 4 个不同的噬菌体群。发现 3 个噬菌体群（PhiFL1 到 3）具有序列相关性，其中 PhiFL1A 到 C 和 PhiFL2A 和 B 具有最大的同源性（87 到 88%），而 PhiFL3A 和 B 与 PhiFL1 和 2 共享 37 到 41%的同源性。PhiFL4A 与 PhiFL1 到 3 噬菌体共享 3 到 12%的同一性。PhiFL3A 和 B 噬菌体与乳酸乳球菌（Lactococcus lactis subsp. cremoris）噬菌体形态发生和裂解模块具有高 DNA 序列同一性。编码链球菌（Streptococcus mitis）血小板结合噬菌体尾部蛋白 PblA 和 PblB 的同源物存在于每个测序的粪肠球菌噬菌体上。还鉴定了少数其他编码潜在毒力功能的噬菌体基因，并且几乎没有证据表明存在溶原性转换基因，而在金黄色葡萄球菌（Staphylococcus aureus）和酿脓链球菌（Streptococcus pyogenes）等机会性病原体的许多温和噬菌体基因组中都观察到了这种情况。使用这 8 个噬菌体生成了粪肠球菌 JH2-2 溶原菌，并在金蝇（Galleria mellonella）中检测了它们的相对适应性。与亲本相比，一些溶原菌对金蝇的存活产生了不同的影响。测试了这 8 个噬菌体包装宿主 DNA 的能力，其中 3 个对实验室菌株 OG1RF 和 JH2-2 的无经验宿主细胞的普遍性转导非常有效。
