He Jiahui, Ruan Wenhao, Sun Jieli, Wang Fang, Yan Wenjuan
Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Department of Neurobiology, School of Basic Medical Science, Southern Medical University, Guangzhou, China.
Front Microbiol. 2018 Aug 29;9:1935. doi: 10.3389/fmicb.2018.01935. eCollection 2018.
The bacterial second messenger cyclic diguanylate monophosphate (c-di-GMP) regulates a series of cellular functions, including biofilm formation, motility, virulence, and other processes. In this study, we confirmed the presence of several c-di-GMP related genes and evaluated their activities and functions in species. Bioinformatic and biochemical analyses revealed that La-14 have an active c-di-GMP phosphodiesterase (PdeA) that may act in the metabolic cycle of c-di-GMP. A GGDEF protein (DgcA) induced two c-di-GMP-dependent phenotypes (low motility and high production of curli fimbriae) in by heterologously expressed but showed no diguanylate cyclases activity while in the expression without the N-terminal transmembrane domain. The degenerated EAL-domain protein (PdeB), encoded by the last gene in the operon, serve as a c-di-GMP receptor which may be associated with exopolysaccharide (EPS) synthesis in . Heterologously expressed GtsA and GtsB, encoded by the operon, stimulated EPS and biofilm formation in BL21. Constitutive expression in revealed that a high concentration of intracellular DgcA levels increased EPS production in and enhanced the co-aggregation ability with MG1655, which may be beneficial to the probiotic properties of species. Our study imply that the c-di-GMP metabolism-related genes, in , work jointly to regulate its functions in EPS formation and co-aggregation.
细菌第二信使环二鸟苷单磷酸（c-di-GMP）调节一系列细胞功能，包括生物膜形成、运动性、毒力和其他过程。在本研究中，我们证实了几种与c-di-GMP相关的基因的存在，并评估了它们在该物种中的活性和功能。生物信息学和生化分析表明，La-14具有一种活性c-di-GMP磷酸二酯酶（PdeA），其可能参与c-di-GMP的代谢循环。一种GGDEF蛋白（DgcA）通过异源表达在该物种中诱导了两种c-di-GMP依赖性表型（低运动性和卷曲菌毛高产量），但在没有N端跨膜结构域的表达中未显示出二鸟苷酸环化酶活性。由该操纵子中的最后一个基因编码的退化EAL结构域蛋白（PdeB）作为一种c-di-GMP受体，可能与该物种中的胞外多糖（EPS）合成有关。由该操纵子编码的异源表达的GtsA和GtsB刺激了大肠杆菌BL21中的EPS和生物膜形成。在该物种中的组成型表达表明，高浓度的细胞内DgcA水平增加了该物种中的EPS产量，并增强了与大肠杆菌MG1655的共聚集能力，这可能有利于该物种的益生菌特性。我们的研究表明，该物种中与c-di-GMP代谢相关的基因共同作用以调节其在EPS形成和共聚集中的功能。
