Effects of metals on enantioselective toxicity and biotransformation of cis‐bifenthrin in zebrafish

Abstract

Co-occurrence of pyrethroids and metals in watersheds previously has been reported to pose great risk to aquatic species. Pyrethroids are a class of chiral insecticides that have been shown to have enantioselective toxicity and biotransformation. However, the influence of metals on enantioselectivity of pyrethroids has not yet been evaluated. In the present study, the effects of cadmium (Cd), copper (Cu), and lead (Pb) on the enantioselective toxicity and metabolism of cis-bifenthrin (cis-BF) were investigated in zebrafish at environmentally relevant concentrations. The addition of Cd, Cu, or Pb significantly increased the mortality of zebrafish in racemate and R-enantiomer of cis-BF-treated groups. In rac-cis-BF- or 1R-cis-BF-treated groups, the addition of Cd, Cu, or Pb caused a decrease in enantiomeric fraction (EF) and an increased ratio of R-enantiomer residues in zebrafish. In 1S-cis-BF-treated groups, coexposure to Cd led to a lower EF and decreased residue levels of S-enantiomer. In addition, coexposure to the 3 metals resulted in different biodegradation characteristics of each enantiomer accompanied with differential changes in the expression of cytochrome P450 (CYP)1, CYP2, and CYP3 genes, which might be responsible for the enantioselective biodegradation of cis-BF in zebrafish. These results suggest that the influence of coexistent metals should be considered in the ecological risk assessment of chiral pyrethroids in aquatic environments. Environ Toxicol Chem 2017;36:2139-2146. © 2017 SETAC.

Stage Dependent Enantioselective Metabolism of Bifenthrin in Embryos of Zebrafish (Danio rerio) and Japanese Medaka (Oryzias latipes)

“…Despite the well-known enantioselectivity in estrogenic effects of cis- BF, , age-related differences in metabolism may contribute to the endocrine effects. In zebrafish embryos, enantioselective transformation to estrogenic metabolites does not appear to be the case as formation of 4-OH-BF is much greater with the 1 R-cis -enantiomer relative to the 1 S-cis enantiomer of BF in stages prior to and after liver development.…”

“…Mechanisms explaining enantioselective toxicity have evaluated the uptake and elimination with in specific tissues of several organisms. − 1 S-cis- BF was degraded more rapidly than 1 R-cis- BF in some strains of bacteria indicating the metabolism of BF in eukaryotic organisms may also be enantioselective . Previous studies also had reported that enantioselective differences in cis -BF residues were observed in zebrafish after exposure. − Oxidation via cytochrome P450 (CYP450) enzymes and hydrolysis through carboxylesterases are two primary metabolic pathways of BF . Carboxylesterase activity has been shown to be selective for trans - isomers of BF catalyzing the formation of (1 RS ,3 RS )-3-[( Z )-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethyl cyclopropane carboxylic acid (TFP acid) and biphenyl acid (BP acid) .…”

Lipid Metabolic Disorder Induced by Pyrethroids in Nonalcoholic Fatty Liver Disease of Xenopus laevis

“…The cis -BF concentrations in exposure solutions ( n = 3 replicates) and the livers ( n = 3 replicates) of X. laevis were extracted according to a previous study . Nine tissue pieces from nine individuals were pooled as one sample replicate.…”

“…The cis-BF concentrations in exposure solutions (n = 3 replicates) and the livers (n = 3 replicates) of X. laevis were extracted according to a previous study. 32 Nine tissue pieces from nine individuals were pooled as one sample replicate. The quantification of cis-BF was performed (three technical replications) using an Acquity-H class plus UPLC (Waters, Massachusetts, USA) interfaced with a Waters Xevo TQ-S Microsystem (Waters, Massachusetts, USA).…”