Department of Microbiology, Pukyong National University, Pusan, 608-737, Republic of Korea.
J Microbiol. 2010 Apr;48(2):213-22. doi: 10.1007/s12275-010-0055-4. Epub 2010 May 1.
A novel bacteriophage that infects Shigella sonnei was isolated from the Gap River in Korea, and its phenotypic and genomic characteristics were investigated. The virus, called SP18, showed morphology characteristic of the family Myoviridae, and phylogenetic analysis of major capsid gene (gp23) sequences classified it as a T4-like phage. Based on host spectrum analysis, it is lytic to S. sonnei, but not to Shigella flexneri, Shigella boydii or members of the genera Escherichia and Salmonella. Pyrosequencing of the SP18 bacteriophage genome revealed a 170-kb length sequence. In total, 286 ORFs and 3 tRNA genes were identified, and 259 ORFs showed similarity (BLASTP e-value<0.001) to genes of other bacteriophages. The results from comparative genomic analysis indicated that the enterophage JS98, isolated from human stool, is the closest relative of SP18. Based on phylogenetic analysis of gp23 protein-coding sequences, dot plot comparison and BLASTP analysis of genomes, SP18 and JS98 appear to be closely related to T4-even phages. However, several insertions, deletions, and duplications indicate differences between SP18 and JS98. Comparison of duplicated gp24 genes and the soc gene showed that duplication events are responsible for the differentiation and evolution of T4-like bacteriophages.
从韩国加德河（Gap River）中分离到一株能感染宋内志贺菌（Shigella sonnei）的新型噬菌体，并对其表型和基因组特征进行了研究。该病毒被命名为 SP18，其形态特征符合肌尾噬菌体科（Myoviridae），主要衣壳蛋白（gp23）基因序列的系统发育分析将其归类为 T4 样噬菌体。根据宿主谱分析，它对宋内志贺菌具有裂解活性，但对福氏志贺菌（Shigella flexneri）、鲍氏志贺菌（Shigella boydii）或埃希氏菌属（Escherichia）和沙门氏菌属（Salmonella）的成员没有活性。SP18 噬菌体基因组的焦磷酸测序揭示了一个 170kb 的长度序列。总共鉴定出 286 个 ORF 和 3 个 tRNA 基因，其中 259 个 ORF 与其他噬菌体的基因具有相似性（BLASTP e 值<0.001）。比较基因组分析的结果表明，从人粪便中分离到的肠噬菌体 JS98 是 SP18 最接近的亲缘关系。根据 gp23 蛋白编码序列的系统发育分析、点图比较和基因组 BLASTP 分析，SP18 和 JS98 似乎与 T4-even 噬菌体密切相关。然而，一些插入、缺失和重复表明 SP18 和 JS98 之间存在差异。比较重复的 gp24 基因和 soc 基因表明，重复事件是导致 T4 样噬菌体分化和进化的原因。
