| 季铵盐抗菌剂在环境中的迁移转化行为及其毒性效应 |
| 摘要点击 1614 全文点击 424 投稿时间：2022-02-22 修订日期：2022-04-20 |
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| 中文关键词 季铵盐(QACs)|迁移转化|毒性效应|抗性机制|协同抗性 |
| 英文关键词 quaternary ammonium compounds (QACs)|migration and transformation|toxic effects|mechanism of resistance|co-resistance |
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| 中文摘要 |
| 季铵盐(QACs)是一类广泛使用的阳离子杀菌剂,流感和新冠肺炎大流行导致其使用量剧增.在其使用或使用后处理处置过程中,QACs可通过各种途径释放到环境中,在水体、沉积物和土壤等多种介质中频繁检出.QACs有较强的表面活性和非专一性的生物毒性,对生态系统构成潜在威胁.围绕QACs在环境介质中的迁移转化、生物毒性效应和细菌出现QACs抗性的主要机制等方面,系统梳理了QACs在环境中的迁移转化行为及其潜在的毒性效应.结果发现好氧生物降解是QACs在环境中的主要衰减途径,降解反应以QACs不同位置C的羟基化来起始,后经过脱羧、脱甲基和β-氧化反应,最终矿化为CO2和H2 O.环境浓度的QACs不会对生物产生致死效应,但会显著影响Daphnia magna等水生生物生长繁殖,毒性效应主要受自身结构、受试生物种类和暴露时长等因素影响.探究了QACs对Microcystis aeruginosa急性毒性的作用机制,发现QACs主要通过破坏光合系统,导致电子传递受限,构成氧化胁迫,破坏细胞膜来抑制Microcystis aeruginosa的生长.QACs在环境中的浓度低于其杀菌浓度,且其生物降解易形成浓度梯度,利于诱导细菌出现QACs抗性.归纳出细菌对QACs抗性机制主要有改变细胞膜结构和组成、形成生物膜、外排泵基因的过度表达以及通过水平转移获取抗性基因.由于作用对象和机制的相似性,QACs也会诱导细菌产生抗生素抗性,主要通过协同抗性和交叉抗性来实现.根据目前的研究现状,提出了未来应重点围绕QACs在实际环境介质中的毒性效应以及对环境微生物抗性的诱导机制展开研究. |
| 英文摘要 |
| Quaternary ammonium compounds (QACs) are one type of widely used cationic biocide, and their usage amount is growing rapidly due to the flu and COVID-19 pandemic. Many QACs were released into the environment in or after the course of their use, and thus they were widely detected in water, sediment, soil, and other environmental media. QACs have stronger surface activity and non-specific biotoxicity, which poses a potential threat to the ecosystem. In this study, the environmental fate and potential toxicity of QACs were documented in terms of their migration and transformation process, biological toxicity effects, and the main mechanisms of bacterial resistance to QACs. Aerobic biodegradation was the main natural way of eliminating QACs in the environment, and the reaction was mainly initiated by the hydroxylation of C atoms at different positions of QACs and finally mineralized to CO2and H2O through decarboxylation, demethylation, and β-oxidation reaction. Toxicological studies showed that QACs at environmental concentrations could not pose acute toxicity to the selected biotas but threatened the growth and reproduction of aquatic organisms like Daphnia magna. Their toxicity effects depended on their molecular structure, the tested species, and the exposed durations. Additionally, our team first investigated the toxicity effects and mechanisms of QACs toward Microcystis aeruginosa, which showed that QACs depressed the algae growth through the denaturation of photosynthetic organelles, suppression of electron transport, and then induction of cell membrane damage. In the environment, the concentrations of QACs were always lower than their bactericidal concentrations, and their degradation could induce the formation of a concentration gradient, which facilitated microbes resistant to QACs. The known resistance mechanisms of bacteria to QACs mainly included the change in cell membrane structure and composition, formation of biofilm, overexpression of the efflux pump gene, and acquisition of resistance genes. Due to the similar targets and mechanisms, QACs could also induce the occurrence of antibiotic resistance, mainly through co-resistance and cross-resistance. Based on the existing data, future research should emphasize the toxicity effect and the potential QACs resistance mechanism of microorganisms in real environmental conditions. |
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