Unité de Recherche en Biologie des Microorganismes (URBM), NARILIS, University of Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France.
Microbiology (Reading). 2012 Oct;158(Pt 10):2642-2651. doi: 10.1099/mic.0.060863-0. Epub 2012 Aug 2.
Bacterial adaptation to environmental conditions is essential to ensure maximal fitness in the face of several stresses. In this context, two-component systems (TCSs) represent a predominant signal transduction mechanism, allowing an appropriate response to be mounted when a stimulus is sensed. As facultative intracellular pathogens, Brucella spp. face various environmental conditions, and an adequate response is required for a successful infection process. Recently, bioinformatic analysis of Brucella genomes predicted a set of 15 bona fide TCS pairs, among which some have been previously investigated. In this report, we characterized a new TCS locus called prlS/R, for probable proline sensor-regulator. It encodes a hybrid histidine kinase (PrlS) with an unusual Na(+)/solute symporter N-terminal domain and a transcriptional regulator (belonging to the LuxR family) (PrlR). In vitro, Brucella spp. with a functional PrlR/S system form bacterial aggregates, which seems to be an adaptive response to a hypersaline environment, while a prlS/R mutant does not. We identified ionic strength as a possible signal sensed by this TCS. Finally, this work correlates the absence of a functional PrlR/S system with the lack of hypersaline-induced aggregation in particular marine Brucella spp.
细菌对环境条件的适应对于在面临多种压力时确保最大适应性至关重要。在这种情况下，双组分系统（TCS）代表一种主要的信号转导机制，允许在感知到刺激时进行适当的响应。作为兼性细胞内病原体，布鲁氏菌属面临着各种环境条件，需要适当的反应才能成功感染。最近，对布鲁氏菌属基因组的生物信息学分析预测了一组 15 对真正的 TCS 对，其中一些已经过先前的研究。在本报告中，我们对一个名为 prlS/R 的新 TCS 基因座进行了特征描述，该基因座可能编码一个脯氨酸传感器-调节剂。它编码一个混合组氨酸激酶（PrlS），具有不寻常的 Na（+）/溶质转运蛋白 N 端结构域和一个转录调节剂（属于 LuxR 家族）（PrlR）。在体外，具有功能性 PrlR/S 系统的布鲁氏菌属形成细菌聚集体，这似乎是对高盐环境的一种适应性反应，而 prlS/R 突变体则不会。我们确定离子强度是该 TCS 可能感知的信号。最后，这项工作将缺乏功能性 PrlR/S 系统与特定海洋布鲁氏菌属缺乏高盐诱导聚集联系起来。
