College of Life Sciences, Henan Normal University, Xinxiang, 453007, China.
College of Life Sciences, Henan Normal University, Xinxiang, 453007, China; School of Public Health, Xinxiang Medical University, Xinxiang, 453003, China.
Environ Res. 2024 Jul 1;252(Pt 1):118861. doi: 10.1016/j.envres.2024.118861. Epub 2024 Apr 3.
Microorganisms have developed mechanisms to adapt to environmental stress, but how microbial communities adapt to long-term and combined heavy-metal contamination under natural environmental conditions remains unclear. Specifically, this study analyzed the characteristics of heavy metal composition, microbial community, and heavy metal resistance genes (MRGs) in sediments along Mang River, a tributary of the Yellow River, which has been heavily polluted by industrial production for more than 40 years. The results showed that the concentrations of Cr, Zn, Pb, Cu and As in most sediments were higher than the ambient background values. Bringing the heavy metals speciation and concentration into the risk evaluation method, two-thirds of the sediment samples were at or above the moderate risk level, and the ecological risk of combined heavy metals in the sediments decreased along the river stream. The high ecological risk of heavy metals affected the microbial community structure, metabolic pathways and MRG distribution. The formation of a HM-resistant microbiome possibly occurred through the spread of insertion sequences (ISs) carrying multiple MRGs, the types of ISs carrying MRGs outnumber those of plasmids, and the quantity of MRGs on ISs is also higher than that on plasmids. These findings could improve our understanding of the adaptation mechanism of microbial communities to long-term combined heavy metal contamination.
微生物已经发展出适应环境压力的机制，但在自然环境条件下，微生物群落如何适应长期和综合的重金属污染仍不清楚。具体来说，本研究分析了黄河支流漫河沉积物中重金属组成、微生物群落和重金属抗性基因（MRG）的特征，该河流已经受到工业生产超过 40 年的严重污染。结果表明，大多数沉积物中 Cr、Zn、Pb、Cu 和 As 的浓度均高于环境背景值。将重金属形态和浓度纳入风险评价方法，三分之二的沉积物样本处于或高于中度风险水平，沉积物中重金属的综合生态风险沿河流降低。重金属的高生态风险影响了微生物群落结构、代谢途径和 MRG 分布。携带多个 MRGs 的插入序列（ISs）的传播可能导致了 HM 抗性微生物组的形成，携带 MRGs 的 ISs 的类型多于质粒，并且 ISs 上的 MRGs 的数量也高于质粒上的数量。这些发现可以提高我们对微生物群落适应长期综合重金属污染的机制的理解。
