College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang Province, China.
College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang Province, China.
Biochem Biophys Res Commun. 2020 Dec 17;533(4):988-994. doi: 10.1016/j.bbrc.2020.09.118. Epub 2020 Oct 1.
Biofilm formation enhances the survival and persistence of microorganisms in response to environmental stresses. It has been revealed that stringent starvation protein A (SspA) can function as an important regulator dealing with environmental stresses for bacterial survival. However, the connection between SspA and biofilm formation is essentially unclear yet. In this study, we presented evidence showing SspA positively controls biofilm formation by up-regulating exopolysaccharides (EPS) production in marine bacterium Pseudoalteromonas sp. R3. Both qPCR and lacZ reporter system congruously revealed that SspA positively controls the expression of EPS biosynthesis gene cluster. Unlike generally accepted thought that SspA regulates bacterial physiology by inhibiting the expression of histone-like nucleotide structuring protein (H-NS) gene, the function of SspA on EPS production and biofilm formation in Pseudoalteromonas sp. R3 is H-NS-independent. Instead, SspA positively regulates the expression of sigma factor AlgU-encoding gene, thus affecting EPS biosynthesis and biofilm formation. In view of the important role of SspA in biofilm formation, we believe that the improvement of tolerance to marine environmental stresses could be related to tuning of SspA-involved biofilm formation.
生物膜的形成增强了微生物对环境胁迫的生存和持久性。已经揭示，严格饥饿蛋白 A（SspA）可以作为一个重要的调节因子，应对细菌生存的环境胁迫。然而，SspA 与生物膜形成之间的联系尚不清楚。在这项研究中，我们提供了证据表明，SspA 通过上调海洋细菌假交替单胞菌 R3 中胞外多糖（EPS）的产生来正向调控生物膜的形成。qPCR 和 lacZ 报告系统一致表明，SspA 正向调控 EPS 生物合成基因簇的表达。与普遍认为的 SspA 通过抑制组蛋白样核苷酸结构蛋白（H-NS）基因的表达来调节细菌生理学的观点不同，SspA 在假交替单胞菌 R3 中对 EPS 产生和生物膜形成的功能是不依赖于 H-NS 的。相反，SspA 正向调节 sigma 因子 AlgU 编码基因的表达，从而影响 EPS 生物合成和生物膜的形成。鉴于 SspA 在生物膜形成中的重要作用，我们认为对海洋环境胁迫的耐受性的提高可能与 SspA 参与的生物膜形成的调节有关。
