Sensor Kinase RscS Induces the Production of Antigenically Distinct Outer Membrane Vesicles That Depend on the Symbiosis Polysaccharide Locus in Vibrio fischeri
Sensor Kinase RscS Induces the Production of Antigenically Distinct Outer Membrane Vesicles That Depend on the Symbiosis Polysaccharide Locus in Vibrio fischeri
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DOI：
10.1128/jb.05926-11
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发表时间：
2012-01-01
影响因子：
3.2
通讯作者：
Visick, Karen L.
中科院分区：
文献类型：
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作者：
Shibata, Satoshi;Visick, Karen L.
费氏弧菌健壮的生物膜形成依赖于共生多糖（syp）位点的激活，这是通过过度表达RscS传感器激酶（RscS(+)）来实现的。然而，除了Syp多糖外，对V. fischeri生物膜基质成分知之甚少。在其他细菌中，生物膜含有多糖、分泌蛋白和外膜囊泡（omv）。在这里，我们询问omv是否是V. fischeri生物膜的一部分。透射电镜显示菌落内细胞间存在omv样颗粒。此外，从RscS（+）和对照细胞的培养上清液中均可纯化omv，对照细胞释放的omv是对照细胞的2- 3倍。这种增加取决于完整syp位点的存在，因为syk缺失的RscS（+）菌株编码一种推定的低聚糖转位酶，显示出omv的产生减少；它还显示出生物膜形成的严重缺陷。Western免疫印迹分析显示，RscS（+）菌株，而不是对照菌株或RscS(+) sypK突变体，产生了一组独特的非蛋白分子，这些分子可以在全细胞提取物、OMV制剂和脂多糖（LPS）提取物中检测到。最后，在其他细菌中影响OMV产生的degP的缺失减少了OMV的产生，降低了细胞形成生物膜的能力。我们得出结论，RscS的过度表达以依赖于syp位点存在的方式诱导OMV的产生，并且在这些条件下产生的OMV含有抗原性不同的分子，可能代表脂多糖（LPS）的修饰形式。最后，我们的数据表明，OMV的产生与费氏弧菌的生物膜形成之间存在相关性。
Robust biofilm formation by Vibrio fischeri depends upon activation of the symbiosis polysaccharide (syp) locus, which is achieved by overexpressing the RscS sensor kinase (RscS(+)). Other than the Syp polysaccharide, however, little is known about V. fischeri biofilm matrix components. In other bacteria, biofilms contain polysaccharides, secreted proteins, and outer membrane vesicles (OMVs). Here, we asked whether OMVs are part of V. fischeri biofilms. Transmission electron microscopy revealed OMV-like particles between cells within colonies. In addition, OMVs could be purified from culture supernatants of both RscS(+) and control cells, with the former releasing 2- to 3-fold more OMVs. The increase depended upon the presence of an intact syp locus, as an RscS(+) strain deleted for sypK, which encodes a putative oligosaccharide translocase, exhibited reduced production of OMVs; it also showed a severe defect in biofilm formation. Western immunoblot analyses revealed that the RscS(+) strain, but not the control strain or the RscS(+) sypK mutant, produced a distinct set of nonproteinaceous molecules that could be detected in whole-cell extracts, OMV preparations, and lipopolysaccharide (LPS) extracts. Finally, deletion of degP, which in other bacteria influences OMV production, decreased OMV production and reduced the ability of the cells to form biofilms. We conclude that overexpression of RscS induces OMV production in a manner that depends on the presence of the syp locus and that OMVs produced under these conditions contain antigenically distinct molecules, possibly representing a modified form of lipopolysaccharide (LPS). Finally, our data indicate a correlation between OMV production and biofilm formation by V. fischeri.