The two-component QseBC signalling system regulates in vitro and in vivo virulence of Aeromonas hydrophila
The two-component QseBC signalling system regulates in vitro and in vivo virulence of Aeromonas hydrophila
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DOI：
10.1099/mic.0.051805-0
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发表时间：
2012-01-01
期刊：
影响因子：
2.8
通讯作者：
Chopra, Ashok K.
中科院分区：
文献类型：
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作者：
Khajanchi, Bijay K.;Kozlova, Elena V.;Chopra, Ashok K.
我们最近证明了N-酰基高丝氨酸内酯[自身诱导剂(AI)-1]和基于LuxS(Al-2)的群体感应(QS)系统分别对腹泻嗜水气单胞菌SSU的毒力产生正和负调节作用。然而，一个新发现的基于双组分的QseBC QS系统在调节细菌毒力方面的作用总体上还不是很清楚，只有有限数量的研究表明它在细菌发病中的作用。在本报告中，我们鉴定和鉴定了嗜水气单胞菌中的qseBC OS系统，并发现，与肠出血性大肠杆菌一样，qseB(反应调节因子)和qsec(传感器组氨酸激酶)基因的开放阅读框在ATGA基序上重叠了4bp。我们的数据表明，嗜水气单胞菌qseB基因的缺失导致了败血症小鼠感染模型中细菌毒力的减弱，游泳和蜂群运动能力减弱，并且突变的细菌形成了比亲本菌株更致密的生物膜。嗜水气单胞菌突变株qseB毒力的降低与蛋白酶和具有溶血活性的细胞毒性肠毒素的产生减少有关。补充qseBC的菌株在游动和聚集运动、溶血活性、蛋白酶产生和生物膜形成方面恢复到与野生型嗜水气单胞菌SSU相似的水平。据我们所知，我们的研究首次报道了一个在嗜水气单胞菌中具有功能的QseBC QS系统，该系统可能与Al-1和Al-2 QS系统相关联，可能通过环二鸟苷一磷酸来调节细菌的毒力。
We recently demonstrated that the N-acyl-homoserine lactone [autoinducer (AI)-1] and LuxS (Al-2)-based quorum-sensing (QS) systems exerted positive and negative regulation, respectively, on the virulence of a diarrhoeal isolate SSU of Aeromonas hydrophila. However, the role of a newly identified, two-component-based QseBC QS system in the regulation of bacterial virulence in general is not well understood, with only a limited number of studies showing its function in bacterial pathogenesis. In this report, we identified and characterized the QseBC OS system in A. hydrophila SSU and found that, as was the case with enterohaemorrhagic Escherichia coli, the open reading frames for the qseB (the response regulator) and qseC (the sensor histidine kinase) genes overlapped by 4 bp at the ATGA motif. Our data provide evidence that deletion of the qseB gene from A. hydrophila resulted in attenuation of bacterial virulence in a septicaemic mouse model of infection and diminished swimming and swarming motility, and the mutant bacteria formed denser biofilms compared with those from the parental strain of A. hydrophila. The decrease in the virulence of the A. hydrophila Delta qseB mutant correlated with reduced production of protease and the cytotoxic enterotoxin, which has associated haemolytic activity. The swimming and swarming motility, haemolytic activity, protease production and biofilm formation were restored in the qseBC-complemented strain to a level similar to that of the wild-type A. hydrophila SSU. Our study is the first, to our knowledge, to report a functional QseBC QS system in A. hydrophila which may be linked to Al-1 and Al-2 QS systems in modulating bacterial virulence, possibly through the cyclic diguanosine monophosphate.