乙醇对瘤胃液接种稻秸的体外发酵产物及细菌群落结构的影响

旨在研究乙醇对山羊瘤胃液与水稻秸秆厌氧共培养的影响。利用频繁传代的体外发酵技术和高通量测序方法,分析了短链脂肪酸(SCFA)产量和细菌群落的变化。结果表明,经体外培养传代8次的稻秸发酵液的总短链脂肪酸产量显著高于瘤胃液(P<0.01);与未添加乙醇的稻秸发酵液相比,添加乙醇显著提高了乙酸、戊酸和己酸的比例,降低了丙酸和丁酸的比例(P<0.01),总SCFA产量及异丁酸和异戊酸比例无显著差异。与瘤胃液相比,稻秸发酵液的拟杆菌门(Bacteroidetes)相对丰度下降,厚壁菌门(Firmicutes)相对丰度升高(P<0.05),且添加乙醇显著提高了厚壁菌门和放线菌门(Actinobacteria)的相对丰度(P<0.05);添加乙醇使双歧杆菌属(Bifidobacterium)、未定性的毛螺菌属(unidentified Lachnospiraceae)、产琥珀酸菌属(Succiniclasticum)、脱硫弧菌属(Desulfovibrio)和未定性的梭菌属(unidentified Clostridiales)的相对丰度显著升高(P<0.05)。乙醇使稻秸发酵液的显著性差异物种(Biomarker)增加;稻秸发酵液与瘤胃液亲缘关系较近,而添加乙醇显著改变了细菌区系;短链脂肪酸比例在稻秸发酵液细菌群落多样性中具有重要作用。研究表明,体外频繁传代和添加乙醇可以提高稻秸发酵液的乙酸、戊酸和己酸产量,乙醇改变了稻秸发酵液的细菌群落结构。     

蕨菜乙醇提取物的Ames试验研究

目的：研究蕨菜乙醇提取物的致突变作用,为蕨菜的开发利用提供一定依据;方法：制备蕨菜乙醇提取物,采用Ames试验方法,以50μg/皿敌克松作为诱变剂,分别添加提取物50、100、200、400、800μg/皿,统计回变菌落数;结果：受试物各剂量组回变菌落数均未超过自发回变菌落数的2倍,且无剂量-反应关系;结论：在本实验条件下,蕨菜乙醇提取物无致突变作用.     

Enzymatic Esterification of Long Polyunsaturated Fatty Acids and Lyso-Phosphatidylcholine in Isooctane and Ethanol

Phosphatidylcholine (PC) was synthesized from lyso-PC and long poly-unsaturated (n-3) fatty acids (PUFA) using immobilized phospholipase A₂. The esterification was performed using the fatty acids as the main solvent and isooctane or ethanol (99.5%) at low concentrations (7–45%) as additional solvents. The temperature was kept constant at 45d`C and the water concentrations were carefully controlled.

The best yield of PC (22%) was found in the isooctane system at a low water content (22% of the dry immobilized enzyme). In the ethanol system, the yield of PC was only half. The best yields were attained when the concentrations of both isooctane and ethanol were below 7% and the reaction time was very long (9 days). Improved contact between the enzyme and the substrates would probably increase the reaction rate.     

The effects of acute ethanol exposure and ageing on rat brain glutathione metabolism

Abstract

Binge alcohol consumption in adolescents is increasing, and it has been proposed that immature brain deals poorly with oxidative stress. The aim of our work was to study the effect of an acute dose of ethanol on glutathione (GSH) metabolism in frontal cortex, hippocampus and striatum of juvenile and adult rats. We have observed no change in levels of glutathione produced by acute alcohol in the three brain areas studied of juvenile and adult rats. Only in the frontal cortex the ratio of GSH/GSSG was increased in the ethanol-treated adult rats. GSH levels in the hippocampus and striatum were significantly higher in adult animals compared to young ones. Higher glutathione peroxidase (GPx) activity in adult rats was observed in frontal cortex and in striatum. Our data show an increased GSH concentration and GPx activity in different cerebral regions of the adult rat, compared to the young ones, suggesting that age-related variations of total antioxidant defences in brain may predispose young brain structures to ethanol-induced, oxidative stress-mediated tissue damage.     

Metabolism of Ethanol to 1-Hydroxyethyl Radicals in Rat Liver Microsomes: Comparative Studies with Three Spin Trapping Agents

Metabolism of ethanol to 1-hydroxyethyl radicals by rat liver microsomes was studied with three nitrone spin trapping agents (POBN, PBN, and DMPO) under essentially comparable conditions. The data indicate that POBN was the superior spin trapping agent for 1-hydroxyethyl radicals, and that DMPO was least efficient. Addition of deferoxamine completely prevented detection of 1-hydroxyethyl radicals with PBN or DMPO, but caused only 50% decrease in EPR signals when POBN was the spin trap. However, superoxide dismutase only decreased 1-hydroxyethyl radical formation when POBN was the spin trap. Other experiments demonstrated that POBN was the most effective of these nitrones for reduction of Fe(III) in aqueous solutions. Furthermore, 1-hydroxyethyl radical adducts were formed when POBN was added to mixtures of ethanol, phosphate buffer, POBN and FeCl₃, but this effect did not occur with either PBN or DMPO. Thus, these data indicate that undesirable effects of POBN on iron chemistry may influence results of spin trapping experiments, and complicate interpretation of the resulting data.     

Ethanol induced the formation of β‐sheet and amyloid‐like fibrils by surfactant‐like peptide A6K

Self‐assembly of natural or designed peptides into fibrillar structures based on β‐sheet conformation is a ubiquitous and important phenomenon. Recently, organic solvents have been reported to play inductive roles in the process of conformational change and fibrillization of some proteins and peptides. In this study, we report the change of secondary structure and self‐assembling behavior of the surfactant‐like peptide A6K at different ethanol concentrations in water. Circular dichroism indicated that ethanol could induce a gradual conformational change of A6K from unordered secondary structure to β‐sheet depending upon the ethanol concentration. Dynamic light scattering and atomic force microscopy revealed that with an increase of ethanol concentration the nanostructure formed by A6K was transformed from nanosphere/string‐of‐beads to long and smooth fibrils. Furthermore, Congo red staining/binding and thioflavin‐T binding experiments showed that with increased ethanol concentration, the fibrils formed by A6K exhibited stronger amyloid fibril features. These results reveal the ability of ethanol to promote β‐sheet conformation and fibrillization of the surfactant‐like peptide, a fact that may be useful for both designing self‐assembling peptide nanomaterials and clarifying the molecular mechanism behind the formation of amyloid fibrils. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.     

Abnormal exhaled ethane concentrations in scleroderma

Abstract

Scleroderma (systemic sclerosis) is a chronic multisystem autoimmune disease in which oxidative stress is suspected to play a role in the pathophysiology. Therefore, it was postulated that patients with scleroderma would have abnormally high breath ethane concentrations, which is a volatile product of free-radical-mediated lipid peroxidation, compared with a group of controls. There was a significant difference (p<0.05) between the mean exhaled ethane concentration of 5.27 pmol ml^–1 CO₂ (SEM=0.76) in the scleroderma patients (n=36) versus the mean exhaled concentration of 2.72 pmol ml^?1 CO₂ (SEM=0.71) in a group of healthy controls (n=21). Within the scleroderma group, those subjects taking a calcium channel blocker had lower ethane concentrations compared with patients who were not taking these drugs (p=0.05). There was a significant inverse association between lung diffusion capacity for carbon monoxide (per cent of predicted) and ethane concentration (b=?2.8, p=0.026, CI=?5.2 to ?0.35). These data support the presence of increased oxidative stress among patients with scleroderma that is detected by measuring breath ethane concentrations.     

The capacity of conophthorin to enhance the attraction of two Xylosandrus species (Coleoptera: Curculionidae: Scolytinae) to ethanol and the efficacy of verbenone as a deterrent

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Taok2 controls behavioral response to ethanol in mice

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