College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
J Hazard Mater. 2024 Jun 5;471:134351. doi: 10.1016/j.jhazmat.2024.134351. Epub 2024 Apr 19.
Macrophyte rhizospheric dissolved organic matter (ROM) served as widespread abiotic components in aquatic ecosystems, and its effects on antibiotic residues and antibiotic resistance genes (ARGs) could not be ignored. However, specific influencing mechanisms for ROM on the fate of antibiotic residues and expression of ARGs still remained unclear. Herein, laboratory hydroponic experiments for water lettuce (Pistia stratiotes) were carried out to explore mutual interactions among ROM, sulfamethoxazole (SMX), bacterial community, and ARGs expression. Results showed ROM directly affect SMX concentrations through the binding process, while CO and N-H groups were main binding sites for ROM. Dynamic changes of ROM molecular composition diversified the DOM pool due to microbe-mediated oxidoreduction, with enrichment of heteroatoms (N, S, P) and decreased aromaticity. Microbial community analysis showed SMX pressure significantly stimulated the succession of bacterial structure in both bulk water and rhizospheric biofilms. Furthermore, network analysis further confirmed ROM bio-labile compositions as energy sources and electron shuttles directly influenced microbial structure, thereby facilitating proliferation of antibiotic resistant bacteria (Methylotenera, Sphingobium, Az spirillum) and ARGs (sul1, sul2, intl1). This investigation will provide scientific supports for the control of antibiotic residues and corresponding ARGs in aquatic ecosystems.
水生植物根际溶解性有机质（ROM）作为水生生态系统中广泛存在的非生物组分，其对抗生素残留和抗生素抗性基因（ARGs）的影响不容忽视。然而，ROM 对抗生素残留命运和 ARGs 表达的具体影响机制仍不清楚。本研究通过室内水培浮萍（Pistia stratiotes）实验，探讨了 ROM、磺胺甲恶唑（SMX）、细菌群落和 ARGs 表达之间的相互作用。结果表明，ROM 通过结合过程直接影响 SMX 浓度，而 CO 和 N-H 基团是 ROM 的主要结合位点。由于微生物介导的氧化还原作用，ROM 分子组成的动态变化使 DOM 库多样化，杂原子（N、S、P）丰度增加，芳香度降低。微生物群落分析表明，SMX 压力显著刺激了水体和根际生物膜中细菌结构的演替。此外，网络分析进一步证实，ROM 生物可利用成分作为能量来源和电子穿梭体，直接影响微生物结构，从而促进了抗生素抗性细菌（Methylotenera、Sphingobium、Az spirillum）和 ARGs（sul1、sul2、intl1）的增殖。该研究为控制水生生态系统中抗生素残留及其相应的 ARGs 提供了科学依据。
