Characterization of a Signaling System in Streptococcus mitis That Mediates lnterspecies Communication with Streptococcus pneumoniae
Characterization of a Signaling System in Streptococcus mitis That Mediates lnterspecies Communication with Streptococcus pneumoniae
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DOI：
10.1128/aem.02297-18
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发表时间：
2019-01-01
影响因子：
4.4
通讯作者：
Petersen, F. C.
中科院分区：
文献类型：
--
作者：
Junges, R.;Sturod, K.;Petersen, F. C.
缓症链球菌存在于口腔和鼻咽中，并构成人类微生物组的重要部分。在这项研究中，计算机分析表明，在S.缓解。虽然Rgg与化脓性链球菌中的阻遏物有更大的相似性，但自诱导试验和基因突变分析表明，在S。缓解Rgg作为激活剂。转录组分析表明，除了shp，该系统调节其他两个下游基因，包括一个假定的lantibiotic基因簇，是在一个接合元件基因座在不同成员的mitis组的一段。与肺炎链球菌中类似的硫醚抗生素基因簇的密切比较表明，S。米提斯缺乏全套基因。尽管SHP有可能引发一个无用的自诱导循环，但在正常或抗生素胁迫条件下，RGG突变体的生长没有受到显著影响。色葡萄然而，mitis SHP在促进种间交流和增加S.肺炎杆菌表面多糖的产生，这在该物种中是由Rgg/SHP调节的。用S.缓症报告菌株。在竞争性测定中，观察到rgg突变体的轻微优势。我们认为S. mitis调节自身slip的表达并激活S. pneumoniae，调节表面多糖合成。从根本上说，这种系统的交叉通信可能在多物种相互作用中发挥作用。重要性细菌分泌信号分子到环境中，当密度达到一定阈值时，其他细胞可以感受到。在这项研究中，我们描述了一个通信系统中的缓症链球菌，从口腔中，我们也发现了几个物种和菌株的链球菌从缓症组的一个寄生虫物种。此外，我们表明，该系统可以促进交叉通信与S。肺炎，一种密切相关的主要人类病原体。重要的是，我们表明，这种交叉交流可以发生在共同文化。而S.缓症可能是一个无效的激活循环的一部分，S。pneumoniae肺炎菌可能与毒力有关。了解这种复杂的通信网络可以为了解细菌群落的动态提供重要的见解。
Streptococcus mitis is found in the oral cavity and nasopharynx and forms a significant portion of the human microbiome. In this study, in silico analyses indicated the presence of an Rgg regulator and short hydrophobic peptide (Rgg/SHP) cell-to-cell communication system in S. mitis. Although Rgg presented greater similarity to a repressor in Streptococcus pyogenes, autoinducing assays and genetic mutation analysis revealed that in S. mitis Rgg acts as an activator. Transcriptome analysis showed that in addition to shp, the system regulates two other downstream genes, comprising a segment of a putative lantibiotic gene cluster that is in a conjugative element locus in different members of the mitis group. Close comparison to a similar lantibiotic gene cluster in Streptococcus pneumoniae indicated that S. mitis lacked the full set of genes. Despite the potential of SHP to trigger a futile cycle of autoinduction, growth was not significantly affected for the rgg mutant under normal or antibiotic stress conditions. The S. mitis SHP was, however, fully functional in promoting cross-species communication and increasing S. pneumoniae surface polysaccharide production, which in this species is regulated by Rgg/SHP. The activity of SHPs produced by both species was detected in cocultures using a S. mitis reporter strain. In competitive assays, a slight advantage was observed for the rgg mutants. We conclude that the Rgg/SHP system in S. mitis regulates the expression of its own slip and activates an Rgg/SHP system in S. pneumoniae that regulates surface polysaccharide synthesis. Fundamentally, cross-communication of such systems may have a role during multispecies interactions.IMPORTANCE Bacteria secrete signal molecules into the environment which are sensed by other cells when the density reaches a certain threshold. In this study, we describe a communication system in Streptococcus mitis, a commensal species from the oral cavity, which we also found in several species and strains of streptococci from the mitis group. Further, we show that this system can promote cross-communication with S. pneumoniae, a closely related major human pathogen. Importantly, we show that this cross-communication can take place during coculture. While the genes regulated in S. mitis are likely part of a futile cycle of activation, the target genes in S. pneumoniae are potentially involved in virulence. The understanding of such complex communication networks can provide important insights into the dynamics of bacterial communities.