Mechanisms for the structural dependent transformation of 6:2 and 8:2 polyfluoroalkyl phosphate diesters in wheat (Triticum aestivum L.)

Unveiling behaviors of 8:2 fluorotelomer sulfonic acid (8:2 FTSA) in Arabidopsis thaliana: Bioaccumulation, biotransformation and molecular mechanisms of phytotoxicity

8:2 fluorotelomer sulfonic acid (8:2 FTSA) has been commonly detected in the environment, but its behaviors in plants are not sufficiently known. Here, the regular and multi-omics analyses were used to comprehensively investigate the bioaccumulation, biotransformation, and toxicity of 8:2 FTSA in Arabidopsis thaliana. Our results demonstrated that 8:2 FTSA was taken up by A. thaliana roots and translocated to leaves, stems, flowers, and seeds. 8:2 FTSA could be successfully biotransformed to several intermediates and stable perfluorocarboxylic acids (PFCAs) catalyzed by plant enzymes. The plant revealed significant growth inhibition and oxidative damage under 8:2 FTSA exposure. Metabolomics analysis showed that 8:2 FTSA affected the porphyrin and secondary metabolisms, resulting in the promotion of plant photosynthesis and antioxidant capacity. Transcriptomic analysis indicated that differentially expressed genes (DEGs) were related to transformation and transport processes. Integrative transcriptomic and metabolomic analysis revealed that DEGs and differentially expressed metabolites (DEMs) in plants were predominantly enriched in the carbohydrate metabolism, amino acid metabolism, and lipid metabolism pathways, resulting in greater energy consumption, generation of more nonenzymatic antioxidants, alteration of the cellular membrane composition, and inhibition of plant development. This study provides the first insights into the molecular mechanisms of 8:2 FTSA stress response in plants.

Hepatotoxicity and lipid metabolism disorders of 8:2 polyfluoroalkyl phosphate diester in zebrafish: In vivo and in silico evidence

8:2 polyfluoroalkyl phosphate diester (8:2 diPAP) has been shown to accumulate in the liver, but whether it induces hepatotoxicity and lipid metabolism disorders remains largely unknown. In this study, zebrafish embryos were exposed to 8:2 diPAP for 7 d. Hepatocellular hypertrophy and karyolysis were noted after exposure to 0.5 ng/L 8:2 diPAP, suggesting suppressed liver development. Compared to the water control, 8:2 diPAP led to significantly higher triglyceride and total cholesterol levels, but markedly lower levels of low-density lipoprotein, implying disturbed lipid homeostasis. The levels of two peroxisome proliferator activated receptor (PPAR) subtypes (pparα and pparγ) involved in hepatotoxicity and lipid metabolism were significantly upregulated by 8:2 diPAP, consistent with their overexpression as determined by immunohistochemistry. In silico results showed that 8:2 diPAP formed hydrogen bonds with PPARα and PPARγ. Among seven machine learning models, Adaptive Boosting performed the best in predicting the binding affinities of PPARα and PPARγ on the test set. The predicted binding affinity of 8:2 diPAP to PPARα (7.12) was higher than that to PPARγ (6.97) by Adaptive Boosting, which matched well with the experimental results. Our results revealed PPAR - mediated adverse effects of 8:2 diPAP on the liver and lipid metabolism of zebrafish larvae.

Perfluoroalkyl acid precursors in agricultural soil-plant systems: Occurrence, uptake, and biotransformation

Perfluoroalkyl acid (PFAA) precursors have been used in various consumer and industrial products due to their hydrophobic and oleophobic properties. In recent years, PFAA precursors in agricultural soil-plant systems have received increasing attention as they are susceptible to biotransformation into metabolites with high biotoxicity risks to human health. In this review, we systematically assessed the occurrence of PFAA precursors in agricultural soils, taking into account their sources and biodegradation pathways. In addition, we summarized the findings of the relevant literature on the uptake and biotransformation of PFAA precursors by agricultural plants. The applications of biosolids/composts and pesticides are the main sources of PFAA precursors in agricultural soils. The physicochemical properties of PFAA precursors, soil organic carbon (SOC) contents, and plant species are the key factors influencing plant root uptakes of PFAA precursors from soils. This review revealed, through toxicity assessment, the potential of PFAA precursors to generate metabolites with higher toxicity than the parent precursors. The results of this paper provide a reference for future research on PFAA precursors and their metabolites in soil-plant systems.