title: Physiological and biochemical responses of the freshwater green algae Closterium ehrenbergii to the common disinfectant chlorine.
abstract: Chlorine (Cl2) is widely used as a disinfectant in water treatment plants and for cleaning swimming pools; it is finally discharged into aquatic environments, possibly causing damage to the non-target organisms in the receiving water bodies. Present study evaluated the effects of the biocide Cl2 to the green alga Closterium ehrenbergii (C. ehrenbergii). Growth rate, chlorophyll a levels, carotenoids, chlorophyll autofluorescence, and antioxidant enzymes were monitored up to 72-h after Cl2 exposure. C. ehrenbergii showed dose-dependent decrease in growth rate and cell division after exposure to Cl2. By using cell counts, the median effective concentration (EC50)-72-h was calculated to be 0.071mgL(-1). Cl2 significantly decreased the pigment levels and chlorophyll autofluorescence intensity, indicating that the photosystem was damaged in C. ehrenbergii. In addition, it increased the production of reactive oxygen species (ROS) in the cells. This stressor significantly increased the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase, and glutathione, and affected the physiology of the cells. These results indicate that Cl2 induces oxidative stress in the cellular metabolic process and leads to physiological and biochemical damages in the green algae. Cl2 discharged in industrial effluents and from water treatment plants may cause harmful effects to the C. ehrenbergii a common freshwater microalgae and other non-target organisms.
authors.affiliation: Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, South Korea.
authors.forename: Ramaraj
authors.initials: R
authors.lastname: Sathasivam
authors.affiliation: Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, South Korea.
authors.forename: Vinitha
authors.initials: V
authors.lastname: Ebenezer
authors.affiliation: Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, South Korea.
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Guo
authors.affiliation: Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, South Korea. Electronic address: kijs@smu.ac.kr.
authors.forename: Jang-Seu
authors.initials: JS
authors.lastname: Ki
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D059001:Aquatic Organisms; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002713:Chlorine / Q000633:toxicity*; D002734:Chlorophyll / Q000031:analogs & derivatives / Q000378:metabolism; D000077194:Chlorophyll A; D000460:Chlorophyta / Q000378:metabolism; D058119:Closterium / Q000187:drug effects* / Q000502:physiology; D004202:Disinfectants / Q000633:toxicity*; D004781:Environmental Exposure / Q000009:adverse effects*; D005618:Fresh Water / Q000737:chemistry*; D005978:Glutathione / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014867:Water / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D004202:Disinfectants; D017382:Reactive Oxygen Species; D014867:Water; D002734:Chlorophyll; C085815:chlorophyll a'; D002338:Carotenoids; D002713:Chlorine; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione; D000077194:Chlorophyll A
keywords: Antioxidant enzyme activity; Chlorophyll autofluorescence; Closterium ehrenbergii; Sodium hypochlorite