The Antiandrogenic Activity of the Fungicide N-(3, 5-Dichlorophenyl) Succinimide in In Vivo and In Vitro Assays

Chemo-Selective Single-Cell Metabolomics Reveals the Spatiotemporal Behavior of Exogenous Pollutants During Xenopus Laevis Embryogenesis

In-depth profiling of embryogenesis-associated endogenous and exogenous metabolic changes can reveal potential bio-effects resulting from human-made chemicals and underlying mechanisms. Due to the lack of potent tools for monitoring spatiotemporal distribution and bio-transformation behavior of dynamic metabolites at single-cell resolution, however, how and to what extent environmental chemicals may influence or interfere embryogenesis largely remain unclear. Herein, a zero-sample-loss micro-biopsy-based mass spectrometric platform is presented for quantitative, chemo-selective, high-coverage, and minimal-destructive profiling of development-associated cis-diol metabolites, which are critical for signal transduction and epigenome regulation, at both cellular level and tissue level of Xenopus laevis. Using this platform, three extraordinary findings that are otherwise hard to achieve are revealed: 1) there are characteristically different cis-diol metabolic signatures among oocytes, anterior and posterior part of tailbud-stage embryos; 2) halogenated cis-diols heavily accumulate at the posterior part of tailbud-stage embryos of Xenopus laevis; 3) dimethachlon, a kind of exogenous fungicide that is widely used as pesticide, may be bio-transformed and accumulated in vertebrate animals in environment. Thus, this study opens a new avenue to simultaneously monitoring intercellular and intraembryonic heterogeneity of endogenous and exogenous metabolites, providing new insights into metabolic remolding during embryogenesis and putting a warning on potential environmental risk.

Degradation of dimethachlon by a newly isolated bacterium Paenarthrobacter sp. strain JH-1 relieves its toxicity against Chlorella ellipsoidea

Dimethachlon, a broad-spectrum dicarboximide fungicide, poses a hazard to the safety of human and ecosystem due to its residue in the environment. A high-efficient dimethachlon degrading bacteria JH-1 belonging to Paenarthrobacter sp. was isolated and characterized. Strain JH-1 can utilize high concentration of dimethachlon as sole carbon source for growth and degrade 98.53% of 300 mg·L^-1 dimethachlon within 72 h. Crude enzyme of strain JH-1 could degrade 99.76% of 100 mg·L^-1 dimethachlon within 2 h. The optimum degradation condition of dimethachlon by strain JH-1 was at 35 °C and pH 7.0. Dimethachlon was degraded in Paenarthrobacter sp. JH-1 as following: it was firstly converted to 4-(3,5-dichloroanilino)-4-oxobutanoic acid and then subjected to the hydrolysis to 3,5-dichloroaniline and succinic acid, the latter was further degraded. Dimethachlon inhibited the growth of Chlorella ellipsoidea, while Paenarthrobacter sp. JH-1 could degrade dimethachlon to relieve its toxicity. This work facilitates our knowledge of the degradation mechanism of dimethachlon and offers potential resource of microbial strains for the bioremediation of dimethachlon-contaminated environments in the future.

Role of leukotrienes in N-(3,5-dichlorophenyl)succinimide (NDPS) and NDPS metabolite nephrotoxicity in male Fischer 344 rats

The agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) can induce marked nephrotoxicity in rats following a single intraperitoneal (ip) administration of 0.4mmol/kg or greater. Although NDPS induces direct renal proximal tubular toxicity, a role for renal vascular effects may also be present. The purpose of this study was to examine the possible role of vasoconstrictor leukotrienes in NDPS and NDPS metabolite nephrotoxicity. Male Fischer 344 rats (4 rats/group) were administered diethylcarbamazine (DEC; 250 or 500mg/kg, ip), an inhibitor of LTA(4) synthesis, 1h before NDPS (0.4mmol/kg, ip), N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS, 0.1, 0.2, or 0.4mmol/kg, ip), or N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA, 0.1mmol/kg, ip) or vehicle. In a separate set of experiments, the LTD(4) receptor antagonist LY171883 (100mg/kg, po) was administered 0.5h before and again 6h after NDHS (0.1mmol/kg, ip) or 2-NDHSA (0.1mmol/kg, ip) or vehicle. Renal function was monitored for 48h post-NDPS or NDPS metabolite. DEC markedly reduced the nephrotoxicity induced by NDPS and its metabolites, while LY171883 treatments provided only partial attenuation of NDHS and 2-NDHSA nephrotoxicity. These results suggest that leukotrienes contribute to the mechanisms of NDPS nephrotoxicity.