海洋希瓦氏菌群体感应对生物被膜形成及厚壳贻贝附着变态的影响

Quorum sensing of Shewanella marisflavi influences biofilm formation and the settlement and metamorphosis of Mytilus coruscus

摘要:

【背景】 细菌群体感应系统调控生物被膜形成，其在海洋无脊椎动物附着变态中发挥重要作用，因此了解群体感应、生物被膜和海洋无脊椎动物变态之间的关系具有重要意义。【目的】 通过添加群体感应抑制剂探究细菌群体感应与生物被膜形成及厚壳贻贝附着变态三者之间的关系。【方法】 将不同的群体感应抑制剂(2-5H-呋喃酮、2-4-噻唑烷二酮、邻苯三酚、呋喃酮C-30、香豆素)作用于海洋希瓦氏菌(Shewanella marisflavi)，利用激光扫描共聚焦显微镜(confocal laser scanning microscopy, CLSM)观察其生物被膜胞外物质的含量，并以厚壳贻贝(Mytilus coruscus)为模型，探究群体感应抑制剂干扰后的细菌生物被膜对厚壳贻贝附着变态的影响。【结果】 群体感应抑制剂可改变希瓦氏菌生物被膜特性，通过减少生物被膜胞外α多糖、蛋白含量，进而降低生物被膜对厚壳贻贝附着变态的诱导率。【结论】 希瓦氏菌群体感应系统可调控生物被膜胞外活性物质的含量，进而间接影响厚壳贻贝幼虫变态能力。

Abstract:

[Background] Biofilms as the main existing form of marine bacteria are related to the settlement and metamorphosis of marine invertebrates and regulated by quorum sensing, and thus it is of great significance to understand the relationship between quorum sensing, biofilm formation, and marine invertebrate metamorphosis. [Objective] To explore the relationship between quorum sensing, biofilm formation, and settlement and metamorphosis of Mytilus coruscus by adding quorum sensing inhibitors. [Methods] Different quorum sensing inhibitors (2-5H-furanone, 2-4-thiazolidinedione, pyrogallol, furanone C-30, and coumarin) were applied to Shewanella marisflavi, and the extracellular polymeric substance content of the biofilm was observed by confocal laser scanning microscopy (CLSM). With M. coruscus as the model, the effects of bacterial biofilms interfered by quorum sensing inhibitors on the settlement and metamorphosis of M. coruscus were studied. [Results] Quorum sensing inhibitors decreased the content of extracellular α-polysaccharide and protein in the biofilm of Shewanella. Furthermore, the post-larval rate of M. coruscus was decreased. [Conclusion] The quorum sensing system of S. marisflavi can regulate the extracellular polymeric substance content of the biofilm, thus indirectly influencing the settlement and metamorphosis of M. coruscus.