Spontaneously Induced Prophages in Lactobacillus gasseri Contribute to Horizontal Gene Transfer
Spontaneously Induced Prophages in Lactobacillus gasseri Contribute to Horizontal Gene Transfer
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DOI：
10.1128/aem.04092-13
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发表时间：
2014-06-01
影响因子：
4.4
通讯作者：
Klaenhammer, T. R.
中科院分区：
文献类型：
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作者：
Baugher, J. L.;Durmaz, E.;Klaenhammer, T. R.
加氏乳杆菌是人类胃肠道和阴道的内源性菌种。随着微生物分类学、系统发育学和基因组学的最新进展，加氏乳杆菌被认为是一种重要的共生菌，并且越来越多地用于益生菌制剂中。 L.gasseri 菌株 ADH 是溶原性的，并含有两个诱导型原噬菌体。在这项研究中，发现原噬菌体 phi adh 在肉汤培养物中自发诱导出稳定期类似于 10(7) PFU/ml 的群体。发现 phi adh 预噬菌体治愈的 ADH 衍生物 NCK102 含有新的第二个诱导型噬菌体 vB_Lga_ jlb1 (jlb1)。噬菌体 jlb1 经过测序，发现与密切相关的噬菌体 LgaI 高度相似，LgaI 在新型菌株 L.gasseri ATCC 33323 中以两个串联前噬菌体的形式存在。 L.gasseri 基因组中常见的多个前噬菌体、它们自发诱导的倾向以及多个乳杆菌种内噬菌体之间的高度同源性表明，温带噬菌体可能有助于水平基因转移(HGT) 存在于共生乳酸杆菌中。在本研究中，针对 16 个 L.gasseri 菌株确定了噬菌体 phi adh 和 jlb1 的宿主范围。在共培养实验中研究了转导范围和自发转导率，以确定原噬菌体在多种共生和益生菌乳酸菌中促进 HGT 的程度。 phi adh 和 jlb1 颗粒均被证实可介导质粒转移。获得了多达10(3)个自发转导子/ml。通过转导共生乳酸杆菌噬菌体的 HGT 可能对人类微生物群内细菌的进化产生重大影响。
Lactobacillus gasseri is an endogenous species of the human gastrointestinal tract and vagina. With recent advances in microbial taxonomy, phylogenetics, and genomics, L. gasseri is recognized as an important commensal and is increasingly being used in probiotic formulations. L. gasseri strain ADH is lysogenic and harbors two inducible prophages. In this study, prophage phi adh was found to spontaneously induce in broth cultures to populations of similar to 10(7) PFU/ml by stationary phase. The phi adh prophagecured ADH derivative NCK102 was found to harbor a new, second inducible phage, vB_Lga_ jlb1 (jlb1). Phage jlb1 was sequenced and found to be highly similar to the closely related phage LgaI, which resides as two tandem prophages in the neotype strain L. gasseri ATCC 33323. The common occurrence of multiple prophages in L. gasseri genomes, their propensity for spontaneous induction, and the high degree of homology among phages within multiple species of Lactobacillus suggest that temperate bacteriophages likely contribute to horizontal gene transfer (HGT) in commensal lactobacilli. In this study, the host ranges of phages phi adh and jlb1 were determined against 16 L. gasseri strains. The transduction range and the rate of spontaneous transduction were investigated in coculture experiments to ascertain the degree to which prophages can promote HGT among a variety of commensal and probiotic lactobacilli. Both phi adh and jlb1 particles were confirmed to mediate plasmid transfer. As many as similar to 10(3) spontaneous transductants/ml were obtained. HGT by transducing phages of commensal lactobacilli may have a significant impact on the evolution of bacteria within the human microbiota.