This study aims to investigate methylmercury (MeHg) demethylation processes in human gut. Here, we determined the compositions and MeHg demethylation rates of gut microbiota in residents from different Hg exposure levels (Wanshan (WS) town and Yangtou (YT) town) and different Hg exposure sources (Zhuchang (ZC) town and YT town) regions. MeHg and inorganic Hg exposure levels in residents of WS town were significantly higher than those of YT and ZC town. Desulfovibrio and Methanogens, which related to Hg methylation/demethylation, showed significantly higher abundance in WS and ZC, comparing with YT. In vitro experiments demonstrated that human intestinal microbiota could degrade MeHg directly. Besides, gut microbiota in WS and ZC exhibited significantly higher demethylation rates than YT, suggesting Desulfovibrio and Methanogens may play important roles in intestinal MeHg demethylation. This study highlights Hg exposure levels and sources may affect demethylation efficiency of gut microbiota, which provides new insights for MeHg demethylation processes in human body.

本研究旨在调查人类肠道中的甲基汞 (MeHg) 去甲基化过程。在这里，我们确定了来自不同汞暴露水平（万山（WS）镇和洋头（YT）镇）和不同汞暴露源（朱昌（ZC）镇和YT镇）地区居民肠道微生物群的组成和甲基汞去甲基化率。WS镇居民MeHg和无机Hg暴露水平显着高于YT和ZC镇。脱硫弧菌和产甲烷菌，与 Hg 甲基化/去甲基化相关的 WS 和 ZC 中的丰度显着高于 YT。体外实验表明，人体肠道微生物群可以直接降解甲基汞。此外，WS 和 ZC 的肠道微生物群的去甲基化率显着高于 YT，这表明脱硫弧菌和产甲烷菌可能在肠道甲基汞去甲基化中起重要作用。本研究强调了汞暴露水平和来源可能会影响肠道微生物群的去甲基化效率，这为人体甲基汞去甲基化过程提供了新的见解。