Histology and metabonomics reveal the toxic effects of kresoxim-methyl on adult zebrafish.

Studies have shown that kresoxim-methyl (KM) and other strobilurin fungicides have toxic effects on aquatic organisms. However, the potential deleterious effects of kresoxim-methyl (KM) on adult zebrafish regarding the ecological risk of environmental concentration remain unclear. Here, the histology and untargeted metabonomics was used to investigate the adverse effect on female zebrafish after exposure to KM at environmental concentration, aquatic life benchmark and one-half LC50 of adult zebrafish. Results demonstrated KM affected zebrafish liver, ovary and intestine development, blurred the boundary between hepatocytes or caused hepatic vacuoles, increased the percentage of perinucleolar oocyte and cortical alveolus oocyte, decreased intestinal goblet cells and disturbed villus and wall integrity after 21 d exposure. Metabonomics showed different concentrations of KM simultaneously influenced the metabolites annotated to vitamin digestion and absorption, serotonergic synapse, retinol metabolism, ovarian steroidogenesis and arachidonic acid (AA) metabolism in zebrafish liver. Results showed the decreased triglyceride and cholesterol levels, as well as the metabolic alterations in amino acid, lipid, vitamin and retinol metabolism caused by KM, might disturb the energy supply for normal liver development and oocyte maturation. In addition, KM altered the transcription of Tdo2a, Tdo2b, Ido1, Cxcl8b, Cyp7a, Cyp11a, Cyp11b, Cyp17a, Cyp19a, Hsd3ß, Hsd17ß, Pla2, Ptgs2a and Ptgs2b, the level of TG, TC, MDA, IFN, IL6 and Ca2+, and the activity of CAT, SOD Ca2+-ATPase in zebrafish liver. Moreover, cytoscape analysis suggested the disturbed AA metabolism caused by KM, might interconnect multiple metabolic pathways to share implicated function in the regulation of oocyte maturation and immune response. Current study brought us closer to an incremental understanding of the toxic mechanism of KM on adult zebrafish, indicated there was crosstalk among different regulatory pathways to regulate the metabolic disorders and biologically hazardous effects induced by KM.

Photo-reduction of Ag nanoparticles by using cellulose-based micelles as soft templates: Catalytic and antimicrobial activities.

Amphiphilic cellulose derivatives were synthesized from allyl cellulose (AC) and cystein (Cys)/n-dodecyl mercaptan (NDM) via the thiol-ene click reactions. The derivatives were self-assembled into micelles in distilled water, and the micelles sizes increased with an increase of the DSNDM. The amphiphilic cellulose micelles were served as the soft templates for the controllable synthesis of Ag nanoparticles (NPs) through the photo-reduction. Ag NPs were embedded and stabilized by the amphiphilic cellulose micelles, and their sizes increased from 3.1 to 14.4 nm with an increase of the original template sizes. The catalytic properties of the Ag-loaded micelles were evaluated by the reduction of p-nitropheonl to p-aminophenol. The results demonstrated that the Ag-loaded micelles exhibited excellent catalytic activity. The reduction followed the first-order rate law, and the reaction constant decreased with increasing size of Ag NPs. Moreover, the Ag-loaded micelles displayed good antimicrobial activities to both S. aureus and E. coli. Therefore, the Ag-loaded cellulose-based micelles have potential applications in various fields.

Novel cellulose polyampholyte-gold nanoparticle-based colorimetric competition assay for the detection of cysteine and mercury(II).

We provide a highly sensitive and selective assay to detect cysteine (Cys) and Hg(2+) in aqueous solutions using Au nanoparticles (NPs) stabilized by carboxylethyl quaternized cellulose (CEQC). This method is based on the thiophilicity of Hg(2+) and Au NPs as well as the unique optical properties of CEQC-stabilized Au NPs. CEQC chains are good stabilizing agents for Au NPs even in a high-salt solution. The addition of Cys results in the aggregation of CEQC-stabilized Au NPs, which induces the visible color change and obvious redshift in UV-visible absorption spectra. On the other hand, Hg(2+) is more apt to interact with thiols than Au NPs; thus, it can remove the Cys and trigger Au NP aggregate redispersion again. By taking advantage of this mechanism, a novel off-on colorimetric sensor has been established for Cys and Hg(2+) detection. This new assay could selectively detect Cys and Hg(2+) with the detection limits as low as 20 and 40 nM in aqueous solutions, respectively.