湿地植物对磺胺类抗生素的吸收与代谢机制研究

Antibiotics have been detected in aquatic environment (e.g., surface water, drinking water and groundwater) due to the abuse of antibiotics in aquaculture, livestock husbandry and clinical care. The low concentration and sustainability input caused the spread of antibiotic resistance bacteria and antibiotic resistance genes. The ecological toxicology effect of antibiotics increased its global concern as an emerging environmental pollutant. Uptake and accumulation of antibiotics in terrestrial plants has been widely studied, but few studies on the wetland plant are poorly understood at themoment.Further study on the transformation mechanism of antibiotics in the wetland plant will help to develop aquatic ecology and aquatic environment subject and implement phytoremediation of aquatic environment pollution.In this project, different wetland plants will be selected as materials, and cultivated in hydroponic solution spiked with SAs . The samples of plants and solution will be collected,and SAs in these samples will be extracted and measured by high performance liquid chromatography coupled with tandem mass spectrometry(HPLC/MS/MS) . The aims of this study are to (1) investigate the main uptake model of SAs by the wetland plants, especially by their roots, and subcellular distribution of SAs in plant roots, stems and leaves as well as their effect factors; (2) clarify the metabolism kinetics of SAs by plant in vivo, the main metabolism tissues, metabolism effectiveness, their key enzymes, and the control factors of the physiology and biochemistry,and infer its possible pathway of metabolism. All results above will be helpful to elucidate the variation and its mechanism of the selected wetland plants, and will provide scientific basis for selecting wetland plants with high absorption and metabolism abilities of antibiotic for phytoremediation of polluted aquatic environment.

养殖业和临床上的不规范使用导致抗生素在水环境中普遍检出,其低浓度和可持续性输入产生如耐药菌和耐药基因等生态效应而引起广泛关注。抗生素作为新型污染物在陆生植物中的吸收累积特性已广泛研究，但在湿地植物中的迁移转化规律鲜有研究。研究抗生素在湿地植物中的迁移转化特征与机制对于促进水生态与水环境学科发展和实现污染水环境植物修复具有重要的理论和现实意义。本项目拟以水环境中普遍检出的典型抗生素(磺胺类)为研究对象，通过水培试验，利用高效液相色谱-串联质谱(HPLC-MS/MS)检测技术，查明不同湿地植物对水环境中典型抗生素的吸收累积特征；探讨湿地植物根系吸收和体内代谢典型抗生素的能力差异及其主要控制因素；从而阐明湿地植物对水环境中典型抗生素的迁移转化特征及其与根系吸收、植物体内代谢作用等之间的关系，对高吸收且高代谢能力湿地植物品种选育和强化人工湿地处理抗生素污染水体环境效率提供科学依据。

湿地植物是人工湿地系统的主体，其净化过程中表现的耐污性、吸收与代谢及解毒功能的解析有助于植物修复技术在污水处理中的应用。本项目开展了湿地植物对环境中持续性输入的磺胺类抗生素（SAs）的吸收与代谢作用的研究，选择水环境中普遍检出并已诱导耐药菌和耐药基因传播的磺胺嘧啶、磺胺吡啶、磺胺甲基嘧啶、磺胺二甲基嘧啶、磺胺甲恶唑作为目标抗生素，以华南地区常见的9种湿地植物为试验材料，通过室内水培试验结合亚细胞分离技术，系统开展从植物器官到亚细胞水平上湿地植物对SAs的吸收、代谢与解毒特征研究及机制探讨，为解析抗生素在湿地植物体内迁移转化特征与机制提供基础数据，并为水环境抗生素污染的植物修复技术提供科学依据。.湿地植物的SAs污染暴露试验发现，试验植物在SAs污染水体中均能正常生长下，表现较强耐性；湿地植物系统能够显著促进水体SAs的去除；9种湿地植物吸收积累SAs特征为灯芯草、风车草>纸莎草、芦竹、泽泻、黄菖蒲、再力花>翠芦莉>美人蕉，根部＞地上部，高污染暴露下植物组织SAs浓度也显著较高。吸收积累高低差异的风车草和美人蕉吸收和代谢作用研究发现，风车草和美人蕉根系吸收存在差异，表现在高积累植物吸收饱和量较高、高污染吸收能力增强、细胞膜上吸收通道蛋白的亲和力较强；风车草和美人蕉体内代谢存在差异，表现在高积累植物代谢效率较高、代谢持久力较强、存在特异性代谢酶，存在多种解毒转化（甲基代谢物、葡萄糖醛酸化代谢物和谷胱甘肽结合物），有效降低植物组织母体SAs含量以及累积的毒性；高积累植物亚细胞上SAs与代谢物的分布存在差异，表现在母体和代谢物含量显著较高，细胞器是湿地植物代谢SAs的主要部位、细胞壁是其主要的储存部位。.综上所述，高积累风车草的根系吸收与代谢能力优于低积累的美人蕉，植物体的代谢能力能提升其吸收饱和能力，解毒能力能增强湿地植物的耐受性，研究证明湿地植物能适应抗生素污水的环境并有效促进抗生素的去除。