Center for Translational Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Zhangjiagang 215600, Jiangsu, China.
Department of Clinical Laboratory, Affiliated Nantong Hospital 3 of Nantong University, Nantong 226006, Jiangsu, China; School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
Gene. 2023 Jan 30;851:146980. doi: 10.1016/j.gene.2022.146980. Epub 2022 Oct 17.
Vibrio parahaemolyticus, a seafood-borne pathogen, is capable of forming biofilms on surfaces. Exopolysaccharide (EPS) plays crucial roles in holding bacterial cells together and keeping biofilm attached on the surface. The cpsA-K and scvA-O gene clusters are responsible for EPS synthesis in V. parahaemolyticus. AphA, the master quorum sensing (QS) regulator operating at low cell density (LCD), positively regulates transcription of cpsA-K and scvA-O, but lacks the detailed mechanisms. The present data showed that the aphA mutant produced smooth colonies, whereas the wild-type strain produced wrinkled colonies. AphA bound the regulatory DNA region of scvE to activate its transcription, whereas it positively regulated transcription of cpsA and scvA in an indirect manner. The transcriptional level of scvE gradually decreased with increasing cell density, which correlated with the expression level of aphA. Taken together, this work elucidated how AphA regulated the biofilm-associated colony morphology variation in V. parahaemolyticus through its regulatory actions on the expression of EPS genes.
副溶血弧菌是一种食源性病原体，能够在表面形成生物膜。胞外多糖 (EPS) 在保持细菌细胞聚集和将生物膜附着在表面上起着至关重要的作用。cpsA-K 和 scvA-O 基因簇负责副溶血弧菌中 EPS 的合成。AphA 是一种在低细胞密度 (LCD) 下起作用的主群体感应 (QS) 调节剂，正向调节 cpsA-K 和 scvA-O 的转录，但缺乏详细的机制。本数据显示，aphA 突变体产生光滑的菌落，而野生型菌株产生皱缩的菌落。AphA 结合 scvE 的调节 DNA 区域以激活其转录，而它以间接方式正向调节 cpsA 和 scvA 的转录。随着细胞密度的增加，scvE 的转录水平逐渐降低，这与 aphA 的表达水平相关。总之，这项工作阐明了 AphA 如何通过对 EPS 基因表达的调节作用来调节副溶血弧菌中与生物膜相关的菌落形态变化。
