State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China.
State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China.
Microbiol Res. 2021 Jun;247:126728. doi: 10.1016/j.micres.2021.126728. Epub 2021 Feb 26.
RpoN (δ54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm formation. However, the knowledge of the roles of rpoN in biofilm formation of V. alginolyticus is limited, especially at different cell densities. Herein, deletion mutant strain ΔrpoN, complementary strain ΔrpoN-C and negative control strain ΔrpoN-Z were constructed to investigate the effects of rpoN on biofilm formation of V. alginolyticus HN08155 based on flagellum and EPS at different cell density conditions. The results showed that all of strains can form biofilm, and biofilms of strains with rpoN were formed at low cell density (LCD) and detached at high cell density (HCD), while those of ΔrpoN and ΔrpoN-Z were absent at LCD and accumulated excessively with a spotty pellicle at HCD without detaching. The EPS contents of strains with rpoN was greater than that of ΔrpoN and ΔrpoN-Z at LCD, while the opposite trends were observed at HCD. The expression levels of rpoN were quantified, which were consistent with the trend of biofilm formation. It's worth noting that absence of rpoN resulted in the failure of biofilm detachment, lacking of flagellum and decreasing motility, indicating that rpoN was not necessary for biofilm formation, but it was essential for biofilm detachment.
RpoN（δ54）作为全局调控因子控制着关键的毒力相关表型，它可以在致病生物膜形成过程中调节鞭毛和胞外多糖（EPS）。然而，关于 rpoN 在 alginolyticus 弧菌生物膜形成中的作用的知识是有限的，尤其是在不同的细胞密度下。在此，构建了缺失突变株 ΔrpoN、互补株 ΔrpoN-C 和阴性对照株 ΔrpoN-Z，以研究 rpoN 在不同细胞密度条件下对 alginolyticus 弧菌 HN08155 生物膜形成的影响，包括鞭毛和 EPS。结果表明，所有菌株都能形成生物膜，rpoN 存在时菌株在低细胞密度（LCD）下形成生物膜并在高细胞密度（HCD）下脱落，而 ΔrpoN 和 ΔrpoN-Z 在 LCD 下不存在生物膜，在 HCD 下过度积累并形成点状菌膜而不脱落。rpoN 存在时菌株在 LCD 下的 EPS 含量大于 ΔrpoN 和 ΔrpoN-Z，而在 HCD 下则呈现相反的趋势。rpoN 的表达水平被定量，这与生物膜形成的趋势一致。值得注意的是，rpoN 的缺失导致生物膜无法脱落，缺乏鞭毛和降低运动性，表明 rpoN 不是生物膜形成所必需的，但对于生物膜脱落是必不可少的。
