Identifying Health Effects of Exposure to Trichloroacetamide Using Transcriptomics and Metabonomics in Mice (Mus musculus)

Microarray-based transcriptomics and one-dimensional proton nuclear magnetic resonance (¹H NMR) based metabonomics approaches were employed to investigate the health effects of nitrogenous disinfection byproducts (N-DBPs) of trichloroacetamide (TCAcAm) on mice. Mice were exposed to TCAcAm at concentrations of 50, 500, and 5000 μg/L for 90 days, and hepatic transcriptome and serum metabonome and histopathological parameters were detected in comparison with those of control. TCAcAm esposures resulted in liver inflammation, weight loss (in 5000 ug/L TCAcAm group), and alterations in hepatic transcriptome and serum metabonome. Based on the differentially expressed genes and altered metabolites, several significant pathways were identified, which are associated with lipid, xenobiotics, amino acid and energy metabolism, and cell process. Moreover, integrative pathway analyses revealed that TCAcAm exposure in this study induced hepatotoxicity and cytotoxicity. These results also highlight the noninvasive prospect of transcriptomic and metabonomic approaches in evaluating the health risk of emerging N-DBPs

Noncovalent Immobilization of a Pyrene-Modified Cobalt Corrole on Carbon Supports for Enhanced Electrocatalytic Oxygen Reduction and Oxygen Evolution in Aqueous Solutions

Efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are the determinants of the realization of a hydrogen-based society, as sluggish OER and ORR are the bottlenecks for the production and utilization of H₂, respectively. A Co complex of 5,15-bis­(pentafluorophenyl)-10-(4)-(1-pyrenyl)­phenylcorrole (<b>1</b>) bearing a pyrene substituent was synthesized. When it was immobilized on multiwalled carbon nanotubes (MWCNTs), the <b>1</b>/MWCNT composite displayed very high electrocatalytic activity and durability for both OER and ORR in aqueous solutions: it catalyzed a direct four-electron reduction of O₂ to H₂O in 0.5 M H₂SO₄ with an onset potential of 0.75 V vs normal hydrogen electrode (NHE), and it catalyzed the oxidation of water to O₂ in neutral aqueous solution with an onset potential of 1.15 V (vs NHE, η = 330 mV). Control studies using a Co complex of 5,10,15-tris­(pentafluorophenyl)­corrole (<b>2</b>) demonstrated that the enhanced catalytic performance of <b>1</b> was due to the strong noncovalent π–π interactions between its pyrene moiety and MWCNTs, which were considered to facilitate the fast electron transfer from the electrode to <b>1</b> and also to increase the adhesion of <b>1</b> on carbon supports. The noncovalent immobilization of molecular complexes on carbon supports through strong π–π interactions appears to be a simple and straightforward strategy to prepare highly efficient electrocatalytic materials

Microcystin-LR Promotes Melanoma Cell Invasion and Enhances Matrix Metalloproteinase-2/‑9 Expression Mediated by NF-κB Activation

This study aimed to explore the molecular mechanisms behind the stimulation effects of microcystin-LR (a well-known cyanobacterial toxin produced in eutrophic lakes or reservoirs) on cancer cell invasion and matrix metalloproteinases (MMPs) expression. Boyden chamber assay showed that microcystin-LR exposure (>12.5 nM) evidently enhanced the invasion ability of the melanoma cells (MDA-MB-435). Tumor Metastasis PCR Array demonstrated that 24 h microcystin-LR treatment (25 nM) caused overexpression of eight genes involved in tumor metastasis, including MMP-2, MMP-9, and MMP-13. Quantitative real-time PCR, Western blotting and gelatin zymography consistently demonstrated that mRNA and protein levels of MMP-2/-9 were increased in the cells after microcystin-LR exposure (<i>P</i> < 0.05 each). Immunofluorescence assay and electrophoretic mobility shift assay revealed that microcystin-LR could activate nuclear factor kappaB (NF-κB) by accelerating NF-κB translocation into the nucleus and enhancing NF-κB binding ability. Furthermore, addition of NF-κB inhibitor in culture medium could suppress the invasiveness enhancement and MMP-2/-9 overexpression. This study indicates that microcystin-LR can act as a NF-κB activator to promote MMP-2/-9 expression and melanoma cell invasion, which deserves more environmental health concerns

Electrocatalytic Water Oxidation by a Water-Soluble Copper(II) Complex with a Copper-Bound Carbonate Group Acting as a Potential Proton Shuttle

Water-soluble copper­(II) complexes of the dianionic tridentate pincer ligand <i>N</i>,<i>N</i>′-2,6-dimethylphenyl-2,6-pyridinedicarboxamidate (<b>L</b>) are catalysts for water oxidation. In [<b>L</b>-Cu^II-DMF] (<b>1</b>, DMF = dimethylformamide) and [<b>L</b>-Cu^II-OAc]⁻ (<b>2</b>, OAc = acetate), ligand <b>L</b> binds Cu^II through three N atoms, which define an equatorial plane. The fourth coordination site of the equatorial plane is occupied by DMF in <b>1</b> and by OAc^– in <b>2</b>. These two complexes can electrocatalyze water oxidation to evolve O₂ in 0.1 M pH 10 carbonate buffer. Spectroscopic, titration, and crystallographic studies show that both <b>1</b> and <b>2</b> undergo ligand exchange when they are dissolved in carbonate buffer to give [<b>L</b>-Cu^II-CO₃H]⁻ (<b>3</b>). Complex <b>3</b> has a similar structure as those of <b>1</b> and <b>2</b> except for having a carbonate group at the fourth equatorial position. A catalytic cycle for water oxidation by <b>3</b> is proposed based on experimental and theoretical results. The two-electron oxidized form of <b>3</b> is the catalytically active species for water oxidation. Importantly, for these two oxidation events, the calculated potential values of <i>E</i>_p,a = 1.01 and 1.59 V vs normal hydrogen electrode (NHE) agree well with the experimental values of <i>E</i>_p,a = 0.93 and 1.51 V vs NHE in pH 10 carbonate buffer. The potential difference between the two oxidation events is 0.58 V for both experimental and calculated results. With computational evidence, this Cu-bound carbonate group may act as a proton shuttle to remove protons for water activation, a key role resembling intramolecular bases as reported previously

Rhodium(III)-Catalyzed Oxidative Annulation of 2,2′-Bipyridine N‑Oxides with Alkynes via Dual C–H Bond Activation

Rh­(III)-catalyzed switchable annulation of 2,2′-bipyridine N-oxides with internal alkynes via dual C–H bond activation has been developed. Tuning the reaction conditions enabled the reaction pathway to be switched between rollover and nonrollover annulation, delivering 5,6-disubstituted-1,10-phenanthrolines and 5,6,7,8-tetrasubstituted-1-(pyridin-2-yl)­isoquinoline 2-oxides in high yields, respectively. The procedures feature excellent regioselectivity, broad substrate scope, and high tolerance of functional groups. The synthetic utilities of these obtained products were demonstrated in the catalytic reactions