Bai Leilei, Zhao Zhen, Wang Chunliu, Wang Changhui, Liu Xin, Jiang Helong
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; Graduate University of Chinese Academy of Sciences, Beijing 100049, PR China.
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China.
Chemosphere. 2017 Nov;187:421-429. doi: 10.1016/j.chemosphere.2017.08.112. Epub 2017 Aug 30.
Interactions of antibiotics with algae-derived dissolved organic matter (ADOM) and macrophyte-derived dissolved organic matter (MDOM) are of vital importance to the transport and ecotoxicity of antibiotics in eutrophic freshwater lakes. Multi-spectroscopic techniques were used to investigate the complexation of tetracycline (TTC) with ADOM and MDOM collected from Lake Taihu (China). The 3 fluorescent components, tyrosine-, tryptophan-, and humic-like component, were identified by excitation emission matrix spectra with parallel factor analysis. Their fluorescence was quenched at different degree by TTC titration through static quenching. The complexation of TTC induced conformational changes in DOM fractions. Synchronous fluorescence spectra combined with two dimensional correlation spectroscopy further suggested that the formation of TTC-DOM complexes occurred on the sequential order of tryptophan-like→tyrosine-like→humic-like component. The effective quenching constants of tryptophan- and tyrosine-like component were similar, higher than those of humic-like component. The strong binding ability and abundant content of protein-like substances indicated their prominent role in the TTC-DOM complexation. Fourier transform infrared spectroscopy further revealed that the heterogeneous functional groups, including amide I and II, aromatics, and aliphatics, were responsible for the complexation. These results highlight the significant impact of the overgrowth of algae and macrophyte on the environmental behavior of antibiotics in waters.
抗生素与藻类衍生溶解有机物（ADOM）和大型植物衍生溶解有机物（MDOM）的相互作用对于富营养化淡水湖泊中抗生素的迁移和生态毒性至关重要。采用多种光谱技术研究了四环素（TTC）与从太湖（中国）采集的ADOM和MDOM的络合作用。通过平行因子分析的激发发射矩阵光谱鉴定出3种荧光成分，即酪氨酸类、色氨酸类和腐殖质类成分。通过静态猝灭，TTC滴定使它们的荧光在不同程度上猝灭。TTC的络合作用引起了DOM组分的构象变化。同步荧光光谱结合二维相关光谱进一步表明，TTC-DOM络合物的形成按类色氨酸→类酪氨酸→类腐殖质成分的顺序依次发生。类色氨酸和类酪氨酸成分的有效猝灭常数相似，高于类腐殖质成分。蛋白质类物质的强结合能力和丰富含量表明它们在TTC-DOM络合中起突出作用。傅里叶变换红外光谱进一步揭示，包括酰胺I和II、芳烃和脂肪族在内的异质官能团是络合作用的原因。这些结果突出了藻类和大型植物过度生长对水中抗生素环境行为的重大影响。
