title: Cellular responses and biodegradation of amoxicillin in Microcystis aeruginosa at different nitrogen levels.
abstract: The influence of nitrogen on the interactions between amoxicillin and Microcystis aeruginosa was investigated using a 7-day exposure test. Growth of M. aeruginosa was not significantly (p>0.05) affected by amoxicillin at the lowest nitrogen level of 0.05 mg L(-1), stimulated by 500 ng L(-1) of amoxicillin at a moderate nitrogen level of 0.5 mg L(-1) and enhanced by 200-500 ng L(-1) of amoxicillin at the highest nitrogen level of 5 mg L(-1). The generation of reactive oxygen species (ROS) and the synthesis of glutathione S-transferases (GST) and glutathione (GSH) were more sensitive to amoxicillin and were stimulated at all nitrogen levels. At the lowest nitrogen level of 0.05 mg L(-1), superoxide dismutase and peroxidase were not effective at eliminating amoxicillin-induced ROS, resulting in the highest malondialdehyde content in M. aeruginosa. The biodegradation of 18.5-30.5% of amoxicillin by M. aeruginosa was coupled to increasing GST activity and GSH content. Elevated nitrogen concentrations significantly enhanced (p<0.05) the stimulation effect of amoxicillin on the growth of M. aeruginosa, the antioxidant responses to amoxicillin and the biodegradation of amoxicillin in M. aeruginosa. The nitrogen-dependent hormesis effect of the coexisting amoxicillin contaminant on the M. aeruginosa bloom should be fully considered during the control of M. aeruginosa bloom.
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China. Electronic address: liuying2010@sdu.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Shandong Urban and Rural Planning Design Institute, Jinan 250013, PR China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Baoyu
authors.initials: B
authors.lastname: Gao
mesh_terms: D000658:Amoxicillin / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism; D001673:Biodegradation, Environmental; D005978:Glutathione / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D046931:Microcystis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D008315:Malondialdehyde; D000658:Amoxicillin; D010088:Oxidoreductases; D013482:Superoxide Dismutase; D005978:Glutathione; D009584:Nitrogen
keywords: Combined pollution; Glutathione conjugation; Hormesis; Reactive oxygen species; Three-way ANOVA