title: Effects of pyrogallic acid on Microcystis aeruginosa: oxidative stress related toxicity.
abstract: Pyrogallic acid (PA) is used in various industrial and consumer products. The molecular mechanisms underlying PA's toxicity was not fully understood. In this study, toxicity of PA on Microcystis aeruginosa with reactive oxygen species (ROS) generation as an end point was investigated. The results showed an increase in the percentage of cells with loss of membrane integrity and enhanced intracellular ROS production. Exposure to 50mgL(-1) PA for 48h caused the highest percentage of loss of membrane integrity (56.7%), and a 2.54-fold higher intracellular ROS level compared to control. Further investigation revealed that PA caused a dose-dependent increase in DNA strand breaks (DSB) of M. aeruginosa at exposure concentration from 2 to 50mgL(-1). The incubation of cells with ROS scavengers ascorbic acid, N-acetyl-l-cysteine (NAC) and tocopherol markedly alleviated the level of PA-induced DSB. Analysis of PA autoxidized products in culture solution showed that PA was quickly converted to purpurogallin (PG), and PG was further autoxidized to other polyphenolic compounds. PA and PG might participate a futile redox cycle, which mediated ROS production in M. aeruginosa. These results suggested DNA strands and cell membrane were two targets of ROS induced by PA, and oxidative damage was an important mechanism for the toxicity of PA against M. aeruginosa.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
authors.forename: Yongyuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Fisheries, Henan Normal University, Xinxiang, Henan 453007, China.
authors.forename: Yunni
authors.initials: Y
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China. Electronic address: liuby@ihb.ac.cn.
authors.forename: Biyun
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China. Electronic address: qhzhou@ihb.ac.cn.
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
authors.forename: Zhenbin
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000111:Acetylcysteine / Q000378:metabolism; D000975:Antioxidants / Q000633:toxicity*; D001205:Ascorbic Acid / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D046931:Microcystis / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D011748:Pyrogallol / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D011748:Pyrogallol; D001205:Ascorbic Acid; D000111:Acetylcysteine
keywords: Allelochemical; Cause-effect relationships; DNA strand breaks; Microcystis aeruginosa; Pyrogallic acid