Genomic analyses of pneumococci reveal a wide diversity of bacteriocins - including pneumocyclicin, a novel circular bacteriocin
Genomic analyses of pneumococci reveal a wide diversity of bacteriocins - including pneumocyclicin, a novel circular bacteriocin
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DOI：
10.1186/s12864-015-1729-4
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发表时间：
2015-07-28
期刊：
影响因子：
4.4
通讯作者：
Brueggemann, Angela B.
中科院分区：
文献类型：
--
作者：
Bogaardt, Carlijn;van Tonder, Andries J.;Brueggemann, Angela B.
背景：肺炎链球菌（“肺炎球菌”）是感染所有年龄组的全球最重要病原体之一。肺炎球菌生活在儿童鼻咽中，它们在那里竞争空间和资源，一种竞争策略是产生细菌素（抗菌肽或蛋白质）来攻击其他细菌，产生免疫蛋白来防止自我毁灭。我们分析了从1916年开始收集的336种不同的肺炎球菌基因组，确定了细菌素盒，详细说明了它们的遗传组成和序列多样性，并在肺炎球菌群体结构的背景下评估了这些数据。结果：我们发现所有基因组都维持一个blp细菌素盒，并鉴定出几个新的blp细菌素盒和基因。blp卡带的“细菌素/免疫区”的组成变化很大：一个卡带具有6个细菌素基因和8个假定的免疫基因，而另一个卡带只有一个。广泛分布和高度克隆的blp磁带被鉴定出来。最令人惊讶的是，三分之一的肺炎球菌基因组还拥有一个编码新型环状细菌素的卡带，我们称之为肺炎霉素，它与其他细菌物种中具有良好特征的环状细菌素卡带具有相似的遗传组织。尘肺环素卡带主要属于一个基因簇，主要存在于七种主要的肺炎球菌克隆复合体中。结论：这些详细的基因组分析揭示了一种新的肺炎霉素盒和多种blp细菌素盒，表明鼻咽部的竞争是一种复杂的生物学现象。
Background: One of the most important global pathogens infecting all age groups is Streptococcus pneumoniae (the 'pneumococcus'). Pneumococci reside in the paediatric nasopharynx, where they compete for space and resources, and one competition strategy is to produce a bacteriocin (antimicrobial peptide or protein) to attack other bacteria and an immunity protein to protect against self-destruction. We analysed a collection of 336 diverse pneumococcal genomes dating from 1916 onwards, identified bacteriocin cassettes, detailed their genetic composition and sequence diversity, and evaluated the data in the context of the pneumococcal population structure.Results: We found that all genomes maintained a blp bacteriocin cassette and we identified several novel blp cassettes and genes. The composition of the 'bacteriocin/immunity region' of the blp cassette was highly variable: one cassette possessed six bacteriocin genes and eight putative immunity genes, whereas another cassette had only one of each. Both widely-distributed and highly clonal blp cassettes were identified. Most surprisingly, one-third of pneumococcal genomes also possessed a cassette encoding a novel circular bacteriocin that we called pneumocyclicin, which shared a similar genetic organisation to well-characterised circular bacteriocin cassettes in other bacterial species. Pneumocyclicin cassettes were mainly of one genetic cluster and largely found among seven major pneumococcal clonal complexes.Conclusions: These detailed genomic analyses revealed a novel pneumocyclicin cassette and a wide variety of blp bacteriocin cassettes, suggesting that competition in the nasopharynx is a complex biological phenomenon.