Enantioselective Degradation Mechanism of Beta-Cypermethrin in Soil From the Perspective of Functional Genes.

The behavior and mechanisms of the enantioselective degradation of beta-cypermethrin were studied in soil. The four isomers were degraded at different rates, and the enantiomer fractions of alpha-cypermethrin and theta-cypermethrin exceeded 0.5. Moreover, 3-phenoxybenzoic acid, phenol, and protocatechuic acid were detected; based on the presence of these metabolites, we predicted the degradation pathway and identified the functional genes that are related to this degradation process. We established quantitative relationships between the data on degradation kinetics and functional genes; we found that the quantitative relationships between different enantiomers differed even under the same conditions, and the genes pobA and pytH played key roles in limiting the degradation rate. Data obtained using path analysis revealed that the same gene had different direct and indirect effects on the degradation of different isomers. A mechanism was successfully proposed to explain the selective degradation of chiral compounds based on the perspective of functional genes.

Yang ZH ，Ji GD 《-》

Quantitative response relationships between degradation rates and functional genes during the degradation of beta-cypermethrin in soil.

In the present study, the degradation mechanisms of beta-cypermethrin and its metabolites in soil were explored through the quantitative response relationships between the degradation rates and related functional genes. We found that the degradation rate of beta-cypermethrin was rapid in unsterilized soil but not in sterilized soil, which indicated that the degradation process is microbially based. Moreover, three metabolites (3-phenoxybenzoic acid, phenol and protocatechuic acid) were detected during the degradation process and used to identify the degradation pathway and functional genes related to the degradation process. The key rate-limiting functional genes were pytH and pobA, and the relative contributions of these genes to the degradation process were examined with a path analysis. The path analysis revealed that the genes pobA and pytH had the greatest direct effects on the degradation of beta-cypermethrin (pobA), alpha-cypermethrin (pobA), theta-cypermethrin (pytH) and 3-phenoxybenzoic acid (pytH).

Yang ZH ，Ji GD 《-》

Stereoselective Degradation and Molecular Ecological Mechanism of Chiral Pesticides Beta-Cypermethrin in Soils with Different pH Values.

Yang ZH ，Ji GD 《-》

Chiral Insecticide α-Cypermethrin and Its Metabolites: Stereoselective Degradation Behavior in Soils and the Toxicity to Earthworm Eisenia fetida.

Yao G ，Jing X ，Peng W ，Liu X ，Zhou Z ，Liu D ... -  《-》

Different degradation patterns and mechanisms of chiral contaminant enantiomers: beta-cypermethrin as a case study.

Studies often neglect the differences between enantiomers in soil chiral contaminants, and the molecular ecological mechanisms involved in enantiomer selective degradation behaviors remain elusive. In the present study, we used the stepwise regression analysis to establish the quantitative relationships between degradation rates and genes that determine different degradation patterns and mechanisms among enantiomers; and beta-cypermethrin (BCYM) was chosen as the target analyte. Stepwise regression analysis demonstrated the relationships established for different enantiomers varied even under the same conditions, and results from path analysis showed the same functional gene exhibited different direct and indirect contributions to different enantiomer degradation rates. The genome and primary microbial communities during different enantiomer degradation rates were also analyzed based on Illumina MiSeq next-generation sequencing technology, and the results indicated the soil microbial community structure and abundance varied during different enantiomer degradation rates. Results from this study served to enhance our understanding of the molecular biological mechanisms of chiral contaminant selective degradation behaviors under the context of functional genes and degrading microorganisms.

Chen M ，Yang ZH 《-》