title: Phototoxicity and oxidative stress responses in Daphnia magna under exposure to sulfathiazole and environmental level ultraviolet B irradiation.
abstract: Sulfonamide antibiotics frequently occur in aquatic environments. In this study, phototoxicity of sulfathiazole (STZ) and its mechanism of action were investigated using Daphnia magna. We evaluated the changes of molecular level stress responses by assessing gene expression, enzyme induction and lipid peroxidation, and the related organism-level effects in D. magna. In the presence of ultraviolet B (UV-B) light (continuous irradiation with 13.8+/-1.0microWcm(-2)d(-1)), STZ (at the nominal concentration of 94.9mg/L) caused a significant increase in reactive oxygen species (ROS) generation and lipid peroxidation. Catalase (CAT) and glutathione S-transferase (GST) showed concentration-dependent increases caused by the exposure. Exposure to STZ and UV-B light caused apparent up-regulation of alpha-esterase, hemoglobin, and vitellogenin mRNA. The survival of daphnids was significantly affected by the co-exposure to STZ and UV-B. The biochemical and molecular level observations in combination with organism-level effects suggest that the phototoxicity of STZ was mediated in part by ROS generated by oxidative stress in D. magna.
authors.affiliation: School of Public Health, Seoul National University, Seoul, 110-799, Republic of Korea. koguma@snu.ac.kr
authors.forename: Jungkon
authors.initials: J
authors.lastname: Kim
authors.forename: Yena
authors.initials: Y
authors.lastname: Park
authors.forename: Kyungho
authors.initials: K
authors.lastname: Choi
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D003621:Daphnia / Q000187:drug effects* / Q000528:radiation effects*; D017484:Dermatitis, Phototoxic; D004777:Environment; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects / Q000528:radiation effects; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000032:analysis; D000077589:Sulfathiazole; D013432:Sulfathiazoles / Q000633:toxicity*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D017382:Reactive Oxygen Species; D013432:Sulfathiazoles; D014874:Water Pollutants, Chemical; D002374:Catalase; D005982:Glutathione Transferase; D000077589:Sulfathiazole