title: Effects of 3-chlorobiphenyl on photosynthetic oxygen production, glutathione content and detoxication enzymes in the aquatic macrophyte Ceratophyllum demersum.
abstract: Organic contaminants of environmental concern such as polychlorinated biphenyls have dispersed widely throughout the ecosystems and accumulate in living organisms, and a variety of adverse biological effects have been reported. In this study, we investigated the effects of 3-chlorobiphenyl in the aquatic macrophyte Ceratophyllum demersum and the capacity of its detoxication system. After 24 h of exposure to various concentrations of 3-chlorobiphenyl, the total glutathione content (tGSH) was determined and the dose-response curves for glutathione reductase (GR) and microsomal/cytosolic glutathione S-transferases (m- and c-GSTs, respectively) were established. C. demersum showed a decrease of photosynthesis after exposure to 3-chlorobiphenyl, although only significantly at 5 microgl(-1). At 0.005 and 0.05 microgl(-1) the GR, m-GST and c-GST activities were significantly increased and concomitantly a non-significant effect on total GSH was observed. At 0.5 microgl(-1), GR as well as c-GST were still significantly induced, while at 5 microgl(-1) none of the enzymes were activated. These results show that detoxication through glutathione conjugation takes place at low concentrations of 3-chlorobiphenyl, while concentrations in the order of parts per billion cause the inactivation of the enzymatic systems evaluated, enough to place C. demersum in an important physiological stress condition.
authors.affiliation: Leibniz Institute of Freshwater Ecology and Inland Fisheries, AG Biogeochemical Regulation, Müggelseedamm 301, Berlin 12587, Germany.
authors.forename: Mirta L
authors.initials: ML
authors.lastname: Menone
authors.forename: Stephan
authors.initials: S
authors.lastname: Pflugmacher
mesh_terms: D001713:Biphenyl Compounds / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism*; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis / Q000187:drug effects*; D010944:Plants / Q000187:drug effects / Q000201:enzymology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D001713:Biphenyl Compounds; D014874:Water Pollutants, Chemical; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005978:Glutathione; D010100:Oxygen; C034280:3-chlorobiphenyl