副溶血弧菌 uvrY 基因缺失株的生物学特性及致病性分析

Biological characteristics and pathogenicity of a uvrY-deleted mutant of Vibrio parahaemolyticus

摘要:

UvrY是BarA/UvrY双组分系统的关键反应调节因子，在调控细菌毒力与环境适应性中起重要作用。 目的 探究UvrY对副溶血弧菌SH112株的生物学特性及致病性的调控作用。 方法 通过同源重组技术构建 uvrY基因缺失株(Δ uvrY)及其互补株(CΔ uvrY)，并采用生长曲线测定、运动能力(泳动和群集运动)、生物被膜形成、细菌竞争、HeLa细胞黏附能力与毒性实验，以及小鼠感染模型(组织载菌量和致死率分析)等多方面实验，系统比较野生株、缺失株和互补株的表型差异。 结果 与野生株相比，Δ uvrY菌株在指数生长后期表现出显著的生长缺陷；运动能力明显下降，其中泳动和群集运动分别降低了33%和70%，但生物被膜形成能力未受到显著影响。此外，Δ uvrY菌株对大肠杆菌的竞争抑制能力减弱，对HeLa细胞的黏附率降低了36.7%，细胞毒性下降了15.8%。小鼠感染实验进一步表明，Δ uvrY菌株的组织定殖能力显著降低，致病性减弱了75%。 结论 本研究揭示了UvrY通过调控副溶血弧菌的生长、运动性、竞争能力和宿主互作等过程在其致病机制中发挥关键作用，为深入理解BarA/UvrY双组分系统的调控网络提供了重要依据。

Abstract:

UvrY is a key response regulator of the BarA/UvrY two-component system (TCS) and plays an important role in regulating bacterial virulence and environmental adaptability. Objective To investigate the regulatory role of UvrY in the biological characteristics and pathogenicity of Vibrio parahaemolyticus SH112. Methods The uvrY-deleted mutant (Δ uvrY) and its complementary strain (CΔ uvrY) were constructed by homologous recombination. Phenotypes were systematically compared among the wild type, mutant, and complementary strains by growth curve plotting, motility (swimming and swarming) assays, biofilm formation assay, bacterial competition assay, HeLa cell adhesion and cytotoxicity assays, as well as a mouse infection model (analysis of bacterial loads in tissues and lethality). Results Compared with the wild type strain, Δ uvrY exhibited significant growth defects during the late exponential phase and weakened motility, with swimming and swarming reduced by 33% and 70%, respectively, while the biofilm formation of the mutant remained unaffected. Additionally, Δ uvrY showed weakened competitive inhibition against Escherichia coli, a 36.7% reduction in HeLa cell adhesion, and a 15.8% decrease in cytotoxicity. Mouse infection experiments further demonstrated that Δ uvrY had significantly reduced tissue colonization capacity and the attenuation of 75% in pathogenicity. Conclusion This study reveals that UvrY plays a crucial role in the pathogenicity of V. parahaemolyticus by regulating the growth, motility, competitive ability, and interaction with the host, giving insights into the regulatory network of the BarA/UvrY two-component system.