Cadmium stress alleviates lipid accumulation caused by chiral penthiopyrad through regulating endoplasmic reticulum stress and mitochondrial dysfunction in zebrafish liver.

The coexistence of cadmium (Cd) can potentiate (synergism) or reduce (antagonism) the pesticide effects on organisms, which may change with chiral pesticide enantiomers. Previous studies have reported the toxic effects of chiral penthiopyrad on lipid metabolism in zebrafish (Danio rerio) liver. The Cd effects and toxic mechanism on lipid accumulation were investigated from the perspective of endoplasmic reticulum (ER) stress and mitochondrial dysfunction. The coexistence of Cd increased the concentrations of penthiopyrad and its metabolites in zebrafish. Penthiopyrad exposure exhibited significant effects on lipid metabolism and mitochondrial function-related indicators, which were verified by lipid droplets and mitochondrial damage in subcellular structures. Moreover, penthiopyrad activated the genes of ER unfolded protein reaction (UPR) and Ca2+ permeable channels, and S-penthiopyrad exhibited more serious effects on ER stress with ER hyperplasia than R-penthiopyrad. As a mitochondrial uncoupler, the coexistence of Cd could decrease lipid accumulation by alleviating ER stress and mitochondrial dysfunction, and these effects were the most significant for R-penthiopyrad. There were antagonistic effects between Cd and penthiopyrad, which could reduce the damage caused by penthiopyrad in zebrafish, thus increasing the bioaccumulation of penthiopyrad in zebrafish. These findings highlighted the importance and necessity of evaluating the ecological risks of metal-chiral pesticide mixtures.

Stereoselective, Diastereoselective Dissipation and Risk Assessment of Chiral Metconazole in Soybean, Peanut, Cabbage, Celery, Tomato, and Soil.

The stereoselective behaviors and dietary risks of metconazole (MZE) in soil and five vegetables were investigated. The results showed that there was species-specific stereoselective and diastereoselective dissipation, and the half-lives ranged from 0.69 to 8.17 days. cis-(+)-1S,5R-MZE was preferentially dissipated in soybean pods, cabbages, celeries, and tomatoes, which was contrary to soybean plants and soil. trans-(+)-1R,5R-MZE was preferentially dissipated in peanut plants, peanut shells, celeries, and tomatoes, while trans-(-)-1S,5S-MZE was preferentially dissipated in soybean plants. cis-MZE was preferentially dissipated in the test vegetables and soil, except celery. The stereoisomeric excess changes were higher than 10%, indicating that the stereoselectivity and diastereoselectivity should be considered in the risk assessment of MZE in soybean plants, pods, and peanut plants. The acute and chronic dietary intake risks of rac-MZE for different groups of people were acceptable. The preferentially dissipated and high activity cis-(+)-1S,5R-MZE with lower toxicity might be suitable for application as monocase.