title: Effects of α-cypermethrin enantiomers on the growth, biochemical parameters and bioaccumulation in Rana nigromaculata tadpoles of the anuran amphibians.
abstract: Populations of many amphibian species are declining worldwide in part because of pesticide contamination. As a surface water contaminant, α-cypermethrin may have severe ecological impacts on amphibians. Here, we examined the acute toxicity of α-cypermethrin enantiomers to dark-spotted frog Rana nigromaculata tadpoles at 24, 48, 72 and 96h, finding that the tadpoles were indeed sensitive to α-cypermethrin. The (S)-(1R, 3R)-enantiomer was approximately 29 times more toxic than the (R)-(1S, 3S)-enantiomer at 96h. A significant delayed growth in R. nigromaculata tadpoles after exposure to 0.5µgL-1of S-(1R, 3R)-cypermethrin was observed. Additionally, increased superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and malondialdehyde (MDA) levels indicate the presence of oxidative stress in the tadpoles. Further, tadpoles exposed to sublethal concentrations of α-cypermethrin enantiomers exhibited enantioselective growth and oxidative damage. Bioaccumulation experiments showed that the tadpoles could rapidly accumulate α-cypermethrin. The (R)-(1S, 3S)-enantiomer was preferentially accumulated over the (S)-(1R, 3R)-enantiomer, and it was also eliminated more quickly, as evidenced in the subsequent depuration experiments.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.affiliation: School of Materials Science and Engineering, Beijing Institute of Fashion Technology, Yinghua RD 2, Beijing 100029, China. Electronic address: ledanhuang0909@163.com.
authors.forename: Ledan
authors.initials: L
authors.lastname: Huang
mesh_terms: D000818:Animals; D007814:Larva / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D018384:Oxidative Stress; D010575:Pesticides / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*; D011722:Pyrethrins / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*; D011898:Ranidae / Q000254:growth & development / Q000378:metabolism; D013237:Stereoisomerism; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D010575:Pesticides; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; C017160:cypermethrin
keywords: Bioaccumulation; Enantioselectivity; Tadpole; Toxicity; α-cypermethrin