中文摘要：

环二腺嘌呤核苷酸（c-di-AMP）是在继环腺嘌呤核苷酸（cAMP）、四（五）磷酸鸟嘌呤核苷（（p）ppGpp）、环二鸟嘌呤核苷酸（c-di-GMP）后新发现的一种第二信使分子，在细菌和支原体中广泛存在。c-di-AMP调控细菌多项生理活动，如细胞周期、细胞壁稳定性、细胞形态、刺激宿主免疫反应以及应对外界环境胁迫等。本文总结了信使分子c-di-AMP自发现以来的研究进展，这些信息可丰富对C-di-AMP调控作用的全面理解。同时，生物信息学分析发现在口腔常见细菌（如变异链球菌和牙龈卟啉单胞菌等）基因组中均存在编码c-di-AMP合成酶的基因，对于这一类基因的功能研究将为深入认识C-di-AMP信号系统在口腔细菌致病过程中的潜在作用提供重要线索，并为研究其在口腔细菌致病性中的调控机制开辟新天地。

英文摘要：

Cyclic di-adenosine monophosphate（c-di-AMP） is a new signal nucleotide, widely distributed among bacteria and archaea, c-di-AMP plays an important role in the regulation of cell growth, cell wall homeostasis, interaction with host immune system and stress response. Bioinformatic analysis revealed that many oral bacterial genomes could encode the c-di-AMP synthase gene. Here we provide an overview of the synthesis and regulation of c-di-AMP in bacteria, highlighting the currently identified receptor proteins and pathways that are directly or indirectly controlled by c-di-AMP, as well as the recognition of c-di-AMP by the eukaryotic host. This review can serve as an important reference for future research of the c-all-AMP signaling system in oral bacteria.