细菌利用细胞间通讯来协调基本的细胞过程,适应环境变化,发展抗生素耐受性,并增强毒力。这个通讯,称为群体感应(QS),由称为自动诱导物的小信号分子的交换介导。AI-2QS,由代谢酶LuxS(S-核糖基高半胱氨酸裂解酶)调节,作为跨革兰氏阳性和革兰氏阴性细菌的通用细胞间通讯机制,对于不同的细菌过程至关重要。在这项研究中,我们证明了在猪链球菌中(S.suis),一种著名的人畜共患病原体,AI-2QS提高半乳糖利用率,上调荚膜多糖(CPS)前体生产的Leloir途径,并促进CPS合成,导致对巨噬细胞吞噬的抵抗力增加。此外,我们的分子对接和动力学模拟表明,类似于肺炎链球菌,FruA,革兰氏阳性病原体中普遍存在的果糖特异性磷酸烯醇丙酮酸磷酸转移酶系统,也可以作为猪链球菌的AI-2膜表面受体。总之,我们的研究证明了AI-2在猪链球菌半乳糖代谢依赖性CPS合成中的意义。此外,我们对FruA作为猪链球菌AI-2的膜表面受体的潜在作用进行了初步分析。
Bacteria utilize intercellular communication to orchestrate essential cellular processes, adapt to environmental changes, develop antibiotic tolerance, and enhance virulence. This communication, known as quorum sensing (QS), is mediated by the exchange of small signalling molecules called autoinducers. AI-2 QS, regulated by the metabolic enzyme LuxS (S-ribosylhomocysteine lyase), acts as a universal intercellular communication mechanism across gram-positive and gram-negative bacteria and is crucial for diverse bacterial processes. In this study, we demonstrated that in Streptococcus suis (S. suis), a notable zoonotic pathogen, AI-2 QS enhances galactose utilization, upregulates the Leloir pathway for capsular polysaccharide (CPS) precursor production, and boosts CPS synthesis, leading to increased resistance to macrophage phagocytosis. Additionally, our molecular docking and dynamics simulations suggest that, similar to S. pneumoniae, FruA, a fructose-specific phosphoenolpyruvate phosphotransferase system prevalent in gram-positive pathogens, may also function as an AI-2 membrane surface receptor in S. suis. In conclusion, our study demonstrated the significance of AI-2 in the synthesis of galactose metabolism-dependent CPS in S. suis. Additionally, we conducted a preliminary analysis of the potential role of FruA as a membrane surface receptor for S. suis AI-2.