Molecular Characterization and Lytic Activities of Streptococcus agalactiae Bacteriophages and Determination of Lysogenic-Strain Features
Molecular Characterization and Lytic Activities of Streptococcus agalactiae Bacteriophages and Determination of Lysogenic-Strain Features
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DOI：
10.1128/jb.00426-09
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发表时间：
2009-08-01
影响因子：
3.2
通讯作者：
Quentin, Roland
中科院分区：
文献类型：
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作者：
Domelier, Anne-Sophie;van der Mee-Marquet, Nathalie;Quentin, Roland
应用丝裂霉素C诱导114个遗传多样的无乳链球菌菌株产生36个噬菌体悬浮液。在噬菌体悬浮液的电子显微镜下，可以将噬菌体归入具有三种不同形态型（A、B和C）的Siphoviridae家族。噬菌体的遗传多样性进行了评估，以PCR为基础的多位点分型方法定位的关键模块位于包装，结构，宿主裂解，溶原性，复制，转录调控簇和整合酶基因和DNA消化与EcoRI，HindIII和ClaI。在6个亲缘关系较远的分子噬菌体群（I至VI）中确定了33个噬菌体群。每个分子组是形态型特异性的，除了形态型A，这是在六个噬菌体群中的五个。基于分子组和形态型定义的各种噬菌体组具有特定的裂解活性，表明每个噬菌体组识别特定的宿主细胞靶标并具有特定的裂解机制。溶原性和繁殖菌株的特性比较表明，在多位点序列分型确定的血清型或克隆复合体（CC）没有差异。然而，由于DL-α-甘油-磷酸底物（CC 17）和α-D-葡萄糖-1-磷酸（CC 19）缺乏分解代谢衰减，所有溶原性CC 17和CC 19菌株均表现出分解代谢损失。此外，CC 17溶原性菌株的DNA在所有S.无乳菌系统发育谱系以外的CC 23，而从非CC 17溶原菌株裂解细菌相似的进化起源。我们的研究结果表明，适应性进化的S。无乳菌的研究使该物种的细菌暴露于各种噬菌体介导的水平基因转移，这可能影响了毒性更强的克隆的适应性。
The application of mitomycin C induction to 114 genetically diverse Streptococcus agalactiae strains generated 36 phage suspensions. On electron microscopy of the phage suspensions, it was possible to assign the phages to the Siphoviridae family, with three different morphotypes (A, B, and C). Phage genetic diversity was evaluated by a PCR-based multilocus typing method targeting key modules located in the packaging, structural, host lysis, lysogeny, replication, and transcriptional regulation clusters and in the integrase genes and by DNA digestion with EcoRI, HindIII, and ClaI. Thirty-three phages clustering in six distantly related molecular phage groups (I to VI) were identified. Each molecular group was morphotype specific except for morphotype A phages, which were found in five of the six phage groups. The various phage groups defined on the basis of molecular group and morphotype had specific lytic activities, suggesting that each recognized particular host cell targets and had particular lytic mechanisms. Comparison of the characteristics of lysogenic and propagating strains showed no difference in the serotype or clonal complex (CC) identified by multilocus sequence typing. However, all the lysogenic CC17 and CC19 strains presented catabolic losses due to a lack of catabolic decay of DL-alpha-glycerol-phosphate substrates (CC17) and of alpha-D-glucose-1-phosphate (CC19). Moreover, the phages from CC17 lysogenic strains displayed lytic replication in bacterial hosts from all S. agalactiae phylogenetic lineages other than CC23, whereas phages obtained from non-CC17 lysogenic strains lysed bacteria of similar evolutionary origin. Our findings suggest that the adaptive evolution of S. agalactiae exposed the bacteria of this species to various phage-mediated horizontal gene transfers, which may have affected the fitness of the more virulent clones.