Li Yisong, Fan Yeshun, Ma Xiaofang, Wang Ying, Liu Jie
School of Public Health, Qingdao University, Qingdao, China.
Qingdao Municipal Center for Disease Control and Prevention, Qingdao, China.
Front Microbiol. 2023 Sep 29;14:1267152. doi: 10.3389/fmicb.2023.1267152. eCollection 2023.
Sialic acids comprise a varied group of nine-carbon amino sugars found mostly in humans and other higher metazoans, playing major roles in cell interactions with external environments as well as other cells. Microbial sialic acid catabolism (SAC) has long been considered a virulence determinant, and appears to be mainly the purview of pathogenic and commensal bacterial species associated with eukaryotic hosts. Here, we used 2,521 (pre-)assembled metagenomes to evaluate the distribution of SAC in microbial communities from diverse ecosystems and human body parts. Our results demonstrated that microorganisms possessing SAC globally existed in non-host associated environments, although much less frequently than in mammal hosts. We also showed that the ecological significance and taxonomic diversity of microbial SAC have so far been largely underestimated. Phylogenetic analysis revealed a strong signal of horizontal gene transfer among distinct taxa and habitats, and also suggested a specific ecological pressure and a relatively independent evolution history in environmental communities. Our study expanded the known diversity of microbial SAC, and has provided the backbone for further studies on its ecological roles and potential pathogenesis.
唾液酸是一类由九个碳原子组成的氨基糖，种类多样，主要存在于人类和其他高等后生动物中，在细胞与外部环境以及其他细胞的相互作用中发挥着重要作用。长期以来，微生物唾液酸分解代谢（SAC）一直被视为一种毒力决定因素，而且似乎主要是与真核宿主相关的致病细菌和共生细菌种类的范畴。在这里，我们使用了2521个（预）组装宏基因组来评估SAC在来自不同生态系统和人体部位的微生物群落中的分布。我们的结果表明，拥有SAC的微生物在全球非宿主相关环境中均有存在，尽管其频率远低于在哺乳动物宿主中的频率。我们还表明，微生物SAC的生态意义和分类多样性迄今为止在很大程度上被低估了。系统发育分析揭示了不同分类群和栖息地之间水平基因转移的强烈信号，并且还表明了环境群落中存在特定的生态压力和相对独立的进化历史。我们的研究扩展了微生物SAC的已知多样性，并为进一步研究其生态作用和潜在发病机制提供了基础。
