Identification and Characterization of a Novel Flagellum-Dependent Salmonella-Infecting Bacteriophage, iEPS5
Identification and Characterization of a Novel Flagellum-Dependent Salmonella-Infecting Bacteriophage, iEPS5
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DOI：
10.1128/aem.00706-13
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发表时间：
2013-08-01
影响因子：
4.4
通讯作者：
Ryu, Sangryeol
中科院分区：
文献类型：
--
作者：
Choi, Younho;Shin, Hakdong;Ryu, Sangryeol
分离并鉴定了一种新的肠沙门氏菌血清型鼠伤寒沙门氏菌（Salmonella enterica serovar Typhimurium）噬菌体iEPS5。iEPS5有一个二十面体的头部和一个长的非收缩性的尾巴与尾纤维。基因组测序结果显示，该基因为59，254 bp的双链DNA，含有73个开放阅读框（ORF）。为了鉴定iEPS5的受体，S.分离对噬菌体具有抗性的鼠伤寒沙门氏菌SL 1344。所有的噬菌体抗性突变体被发现有参与鞭毛形成的基因突变，这表明鞭毛是这种噬菌体的吸附目标。使用有鞭毛但不运动的Delta motA突变体进行的噬菌体感染分析证明了iEPS5感染需要鞭毛旋转。使用Delta cheY突变体对噬菌体感染的进一步分析显示，iEPS5仅在鞭毛逆时针旋转（CCW）时才能感染宿主细菌。这些结果表明，CCW旋转鞭毛丝是噬菌体吸附所必需的，并且是iEPS5成功感染所必需的。与充分研究的鞭毛性噬菌体Chi相反，iEPS5不能感染Delta fliK突变体，该突变体在没有鞭毛丝的情况下产生多钩，这表明这两种鞭毛性噬菌体利用不同的感染机制。在这里，我们提出的证据表明，iEPS5注入其DNA到鞭毛丝感染通过评估DNA转移SYBR金标记的iEPS5的宿主细菌。
A novel flagellatropic phage of Salmonella enterica serovar Typhimurium, called iEPS5, was isolated and characterized. iEPS5 has an icosahedral head and a long noncontractile tail with a tail fiber. Genome sequencing revealed a double-stranded DNA of 59,254 bp having 73 open reading frames (ORFs). To identify the receptor for iEPS5, Tn5 transposon insertion mutants of S. Typhimurium SL1344 that were resistant to the phage were isolated. All of the phage-resistant mutants were found to have mutations in genes involved in flagellar formation, suggesting that the flagellum is the adsorption target of this phage. Analysis of phage infection using the Delta motA mutant, which is flagellated but nonmotile, demonstrated the requirement of flagellar rotation for iEPS5 infection. Further analysis of phage infection using the Delta cheY mutant revealed that iEPS5 could infect host bacteria only when the flagellum is rotating counterclockwise (CCW). These results suggested that the CCW-rotating flagellar filament is essential for phage adsorption and required for successful infection by iEPS5. In contrast to the well-studied flagellatropic phage Chi, iEPS5 cannot infect the Delta fliK mutant that makes a polyhook without a flagellar filament, suggesting that these two flagellatropic phages utilize different infection mechanisms. Here, we present evidence that iEPS5 injects its DNA into the flagellar filament for infection by assessing DNA transfer from SYBR gold-labeled iEPS5 to the host bacteria.