Enantioselective Assessment of Etoxazole Enantiomers in Earthworms (): Bioaccumulation, Degradation, Transcriptome, and Oxidative Stress.

This study systemically investigated the enantioselective bioaccumulation and degradation of etoxazole (ETZ) in earthworms along with the transcriptome and oxidative stress responses to ETZ enantiomer exposure. Based on the M-shaped bioaccumulation trends for ETZ enantiomers, -ETZ was found to be preferentially bioaccumulated in earthworms. Sublethal toxicity analysis showed that -ETZ induced greater changes in protein content, malondialdehyde content, detoxifying metabolic enzyme activity, and oxidative stress in earthworms, compared to those induced by -ETZ. Integrated biomarker response analysis suggested that -ETZ induced higher sublethal toxicity in earthworms than -ETZ. Finally, transcriptomic analysis indicated that 845 and 314 genes were differentially expressed after -ETZ and -ETZ exposure, respectively, when compared to the nonexposed control group. Enrichment analysis indicated that these differentially expressed genes were primarily enriched in the digestion and absorption of proteins, lysosome, peroxisome, and peroxisome proliferator-activated receptor signaling pathways. These results suggest that earthworms exhibit distinct enantioselective responses to -ETZ and -ETZ. This study elucidates the enantioselective bioaccumulation, degradation, transcriptome, and oxidative stress characteristics of ETZ enantiomers in earthworms at the enantiomer level, offering a theoretical foundation to improve the risk assessment of ETZ in the soil-earthworm microsomes.