Ion–molecule reactions of Mg+(H2O)n (n≈20–60) with CH3CN are studied by Fourier‐transform ion‐cyclotron resonance mass spectrometry. Collision with CH3CN initiates the formation of MgOH+(H2O)n−1 ...together with CH3CHN. or CH3CNH., which is similar to the reaction of hydrated electrons (H2O)n− with CH3CN. In subsequent reaction steps, three more CH3CN molecules are taken up by the clusters, to form MgOH+(CH3CN)3 after a reaction delay of 60 seconds. Density functional theory (DFT) calculations at the M06/6‐31++G(d,p) level of theory suggest that the bending motion of CH3CN allows the unpaired electron that is solvated out from the Mg center to localize in a π*(CN)‐like orbital of the bent CH3CN.−, which undergoes spontaneous proton transfer to form CH3CNH. or CH3CHN., with the former being kinetically more favorable. The reaction energy for a cluster with the hexacoordinated Mg center is more exothermic than that with the pentacoordinated Mg. The CH3CNH. or CH3CHN. is preferentially solvated on the cluster surface rather than at the first solvation shell of the Mg center. By contrast, the three additional CH3CN molecules taken up by the resulting MgOH+(H2O)n clusters coordinate directly to the first solvation shell of the MgOH+ core, as revealed by DFT calculations.
Electron squeeze‐out: The redox chemistry of the Mg+ ion with CH3CN in aqueous media has been demonstrated at the molecular level. The valence electron of Mg+ is solvated out by water (see figure) and can reduce the CH3CN molecule to form CH3CN.−, followed by a spontaneous proton transfer to give CH3CNH. or CH3CHN..
The effects of a white wine enriched with polyphenols (PEWW) from Chardonnay grapes and of a sparkling red wine (SRW) from Pinot Noir and Chardonnay grapes were studied for the first time on early ...atherosclerosis in hamsters. Animals were fed an atherogenic diet for 12 weeks. They received by force-feeding PEWW, SRW, ethanol 12% (ETH), or water as control (mimicking a moderate consumption of ∼2 red wine glasses per meal for a 70 kg human). Plasma cholesterol concentrations were lower in groups that consumed PEWW and SRW accompanied by an increase in the ratio apo A-1/apo B. Liver-specific activities of superoxide dismutase and catalase were significantly increased by PEWW (38 and 16%, respectively) and by SRW (48 and 15%, respectively). PEWW and ETH significantly increased plasma antioxidant capacity and vitamin A concentrations. Aortic fatty streak area (AFSA) was significantly strongly reduced in the groups receiving PEWW (85%) and SRW (89%) in comparison with the control. AFSA was reduced by ethanol to a lesser extent (58%). These data suggest that tannins from the phenolics-enriched white wine induce a protective effect against early atherosclerosis comparable to that produced by sparkling red wine containing tanins and anthocyanins and dissociated from the antioxidant action of these compounds. Keywords: Atherosclerosis; phenolics-enriched white wine; sparkling red wine; phenolic compounds; tannins; ethanol; hamsters
Plants are known to secrete chemical compounds that can change the behavior of rhizosphere-inhabiting bacteria. We investigated the effects of extracts from legume host plants on the swarming ...behavior of Rhizobium leguminosarum bv. viciae. We also investigated the effects on swarming when Rhizobium is exposed to extracts from an ancestor to vascular plants, the model bryophyte Physcomitrella patens. Lentil and faba bean seed exudates enhanced and inhibited swarming motility, respectively, whereas pea seed exudates had no observable effect on swarming. Swarming was also enhanced by the moss extracts. Exposure to lentil seed exudates and the moss extract increased flaA expression 2-fold, while faba bean seed exudates exposure decreased expression 3-fold, suggesting that the swarming effect could, in part, be due to regulation of flagellin gene expression. However, the exudates and extracts did not significantly affect flaA gene expression in planktonic motile cells, indicating that the response to flagellar regulation is specific to a physiology unique to the swarming cell. Transmission electron microscopy demonstrated that addition of the lentil seed exudate and the moss extract results in earlier differentiation into swarmer cells, which could contribute to the development of a larger swarming surface area. To gain further mechanistic insight into the effect of the moss extract on swarming, a moss strigolactone-deficient mutant (Ppccd8Δ) was tested. A reduction in the promotive effect was observed, suggesting that the plant hormone strigolactone may be a signalling molecule activating swarming motility in R.leguminosarum.
To examine the relative levels of gamma-aminobutyric acid (GABA), glutamate, and vascular endothelial growth factor (VEGF) in the vitreous of nondiabetic and diabetic patients.
Undiluted vitreous ...samples were obtained from 22 patients with proliferative diabetic retinopathy (PDR) and 28 patients without diabetes who underwent pars plana vitrectomy. Simultaneous venous blood samples also were obtained. Amino acid concentrations were determined using sensitive high-performance liquid chromatography, and VEGF levels by quantitative enzyme-linked immunosorbent assay. Hemoglobin concentrations in the blood and vitreous were determined using spectrophotometry.
The level of GABA in the vitreous of patients with PDR, 29.4 +/- 7.8 mumol/L, was significantly higher than in controls (18.4 +/- 5.5 mumol/L) (P = .004). The vitreous concentration of glutamate was higher in patients with PDR (24.7 +/- 14.0 mumol/L) compared with controls (9.1 +/- 5.1 mumol/L) (P < .001). Vitreous VEGF level was significantly higher in patients with PDR (1759 +/- 1721 pg/mL) compared with controls (27 +/- 65 pg/mL) (P < .001). There were moderately strong correlations between GABA and VEGF levels (r = 0.68) and glutamate and VEGF levels (r = 0.43). Elevated GABA, glutamate, and VEGF levels also correlated strongly with the presence of PDR. Correcting for possible introduction of these molecules by vitreous hemorrhage did not significantly alter these findings.
Levels of glutamate potentially toxic to retinal ganglion cells are found in the vitreous of patients with PDR. Elevated vitreous GABA may reflect amacrine cell dysfunction and underlie electroretinographic oscillatory potential abnormalities seen in diabetic retinopathy. The correlations of glutamate and GABA levels with an elevated VEGF level provide biochemical support for ischemia-induced neovascularization in patients with PDR. These findings present opportunities for novel therapeutic modalities in the treatment of PDR.
Impaired bowel function is frequent in tube-fed patients, and diarrhoea is associated with decreased faecal short-chain fatty acids (SCFAs) concentrations. The aim of this study was to compare the ...effects of a multi-fibre-enriched formula (15
g/l) and a fibre-free isoenergetic and isonitrogenous formula on faecal SCFAs and microbiota in long-term enteral nutrition (EN) patients.
Fifteen patients 11M/4F, aged 53 (40–73) on total EN for 43 (1–310) months for dysphagia received a fibre-free formula for 7 days, followed in a random order by either the multi-fibre-enriched formula for 14 days and then the fibre-free formula for 14 days or vice versa. Stool samples were taken at the end of each period for measurement of SCFAs levels and different groups of bacteria. Results were compared with non-parametric tests.
After the multi fibre EN, there was a significant median increase in total faecal SCFAs (+84%), butyrate (+20%) and acetate (+147%) compared with baseline. A significant increase in the total number of bacteria as determined with the molecular method was found after the multi-fibre EN period compared with the fibre-free EN period. There were no concomitant changes in the dominant groups of intestinal bacteria.
In long-term EN patients, a polymeric enteral formula supplemented with a mixture of six fibres increases faecal SCFAs and total number of bacteria, which may contribute to an improved bowel function.
Das fehlende Stück in einem fesselnden Puzzle: Mehr als zehn Jahre nach der theoretischen Vorhersage, dass kationisches CuO+ ein wirkungsvoller Kandidat für die Umwandlung von Methan zu Methanol sein ...müsste, konnte dieses Oxid in der Gasphase erzeugt werden. Eine Kombination aus Massenspektrometrie und DFT‐Rechnungen offenbart die entscheidende Rolle der Zweizustandsreaktivität sowie die Bedeutung von sauerstoffzentrierten Radikalen hinsichtlich der Selektivität in der Oxidation von Methan.
Peroxynitrite (ONOO-) is a cytotoxic product of the rapid reaction between nitric oxide and superoxide that may initiate inflammation. Isolated perfused tracheas from guinea pigs were incubated from ...the mucosal side for 15 min with peroxynitrite (1 to 100 muM). Thereafter, concentration-response curves to histamine and methacholine were constructed on the preparations. Peroxynitrite (10 muM) caused a significant hyperresponsiveness; the maximal contractions in response to histamine and methacholine were enhanced by 30% and 40%, respectively. In the peroxynitrite-treated group, clear epithelial damage as well as eosinophil destruction were detected. Moreover, 3, 5, and 10 days after intratracheal instillation of peroxynitrite (100 nmol), a significant rise in pulmonary resistance to histamine of anesthetized animals was observed. It is suggested that the generation of peroxynitrite from nitric oxide superoxide radicals during inflammatory processes induces epithelial damage, mediator release, and hence airway hyperresponsiveness. These findings may have clinical implications, because airway inflammation, epithelial damage, and hyperresponsiveness are characteristic features in patients suffering from asthma.
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