title: The combined effects of UV-C radiation and H2O2 on Microcystis aeruginosa, a bloom-forming cyanobacterium.
abstract: In order to get insight into the impacts of UVC/H2O2 on Microcystis aeruginosa, physiological and morphological changes as well as toxicity were detected under different UVC/H2O2 treatments. In the presence of sole UVC or H2O2, the net oxygen evolution rate decreased significantly (p<0.05) since activity of photosystem II (PSII) was inhibited. Meanwhile, increase of intracellular reactive oxygen species (ROS), degradation of microcystin (MC) and ultrastructure destructions were observed. Under sole UVC treatment, no changes happened in the activity of photosystem I (PSI), but the degradation of D1 protein was observed. Under sole H2O2 treatment, an increase of malondialdehyde, aggregation of D1 protein and deformation of the thylakoid membrane were observed. ROS content under H2O2 treatment was about 5 times than that under UVC treatment. Combined use of UVC and H2O2, as well as 20mJcm(-2) UVC and 60μM H2O2, showed high synergetic effects. Obvious damage to membrane systems, the marked degradation of MC and inhibition of the photosystems were observed. It could be deduced that UVC worked on intracellular membrane components directly and the damaged oxygen-evolving complex, which was followed by the D1 protein degradation. H2O2 oxidised the membrane lipids via an ROS-mediated process, with thylakoid injury and the aggregation of D1 protein being the lethal mechanisms, and both PSII and PSI being the attacking targets. With regard towards the effective inactivation of M. aeruginosa and high removal of MC, UVC/H2O2 proposed a novel practical method in controlling cyanobacterial blooms.
authors.affiliation: Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Binliang
authors.initials: B
authors.lastname: Wang
authors.affiliation: Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Mingxian
authors.initials: M
authors.lastname: Chang
authors.affiliation: Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: biyh@ihb.ac.cn.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Bi
authors.affiliation: Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Hu
mesh_terms: D005068:Eutrophication / Q000187:drug effects / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008315:Malondialdehyde / Q000378:metabolism; D052998:Microcystins / Q000378:metabolism; D046931:Microcystis / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D045332:Photosystem II Protein Complex / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D052998:Microcystins; D045332:Photosystem II Protein Complex; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; C078588:microcystin; D006861:Hydrogen Peroxide
keywords: Cyanobacterial bloom; H(2)O(2); Photosystem; UVC