Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA.
San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, 92093, USA.
Sci Rep. 2021 Feb 26;11(1):4763. doi: 10.1038/s41598-021-83875-w.
N-Acetylneuraminic acid is the most abundant sialic acid (SA) in humans and is expressed as the terminal sugar on intestinal mucus glycans. Several pathogenic bacteria harvest and display host SA on their own surfaces to evade Siglec-mediated host immunity. While previous studies have identified bacterial enzymes associated with SA catabolism, no reported methods permit the selective labeling, tracking, and quantitation of SA-presenting microbes within complex multi-microbial systems. We combined metabolic labeling, click chemistry, 16S rRNA gene, and whole-genome sequencing to track and identify SA-presenting microbes from a cultured human fecal microbiome. We isolated a new strain of Escherichia coli that incorporates SA onto its own surface and encodes for the nanT, neuA, and neuS genes necessary for harvesting and presenting SA. Our method is applicable to the identification of SA-presenting bacteria from human, animal, and environmental microbiomes, as well as providing an entry point for the investigation of surface-expressed SA-associated structures.
N-乙酰神经氨酸是人类中最丰富的唾液酸（SA），并作为肠道粘液糖蛋白的末端糖表达。几种致病性细菌在其自身表面收获和展示宿主 SA，以逃避 Siglec 介导的宿主免疫。虽然先前的研究已经确定了与 SA 分解代谢相关的细菌酶，但没有报道的方法可以在复杂的多微生物系统中选择性标记、跟踪和定量呈现 SA 的微生物。我们结合代谢标记、点击化学、16S rRNA 基因和全基因组测序，从培养的人类粪便微生物组中跟踪和鉴定呈现 SA 的微生物。我们分离出一株新的大肠杆菌，它将 SA 整合到自身表面，并编码用于收获和呈现 SA 的 nanT、neuA 和 neuS 基因。我们的方法适用于从人类、动物和环境微生物组中鉴定呈现 SA 的细菌，并为研究表面表达的 SA 相关结构提供了一个切入点。
