The influence of ethanol on intestinal absorption and utilization of nutrients.
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Amino Acids↗
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Intracellular signaling pathways that regulate behavioral responses to ethanol.
Recent evidence indicates that ethanol modulates the function of specific intracellular signaling cascades, including those that contain cyclic adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase A (PKA), protein kinase C (PKC), the tyrosine kinase Fyn, and phospholipase D (PLD). In some cases, the specific components of these cascades appear to mediate the effects of ethanol, whereas other components indirectly modify responses to ethanol. Studies utilizing selective inhibitors and genetically modified mice have identified specific isoforms of proteins involved in responses to ethanol. The effects of ethanol on neuronal signaling appear restricted to certain brain regions, partly due to the restricted distribution of these proteins. This likely contributes specificity to ethanol's actions on behavior. This review summarizes recent work on ethanol and intracellular signal transduction, emphasizing studies that have identified specific molecular events that underlie behavioral responses to ethanol.
Adenylyl Cyclases↗
Mutants of Pachysolen tannophilus with Improved Production of Ethanol from d-Xylose.
The conversion of d-xylose to ethanol by the yeast Pachysolen tannophilus is relatively inefficient in batch culture. The inefficiency has been attributed in part to concurrent utilization of ethanol in the presence of appreciable concentrations of d-xylose and to the formation of xylitol and other by-products. To increase the concentration of ethanol accumulated in batch cultures, UV-induced mutants of P. tannophilus were selected on the basis of diminished growth on ethanol. Eleven independent mutant loci that conferred the ethanol-defective phenotype were identified. Three led to a greater yield and volumetric rate of production of ethanol than the wild type. One also produced less xylitol and was characterized by a deficiency in activity for malate dehydrogenase.
Journal Article↗
Deletion of the GRE3 aldose reductase gene and its influence on xylose metabolism in recombinant strains of Saccharomyces cerevisiae expressing the xylA and XKS1 genes.
Saccharomyces cerevisiae ferments hexoses efficiently but is unable to ferment xylose. When the bacterial enzyme xylose isomerase (XI) from Thermus thermophilus was produced in S. cerevisiae, xylose utilization and ethanol formation were demonstrated. In addition, xylitol and acetate were formed. An unspecific aldose reductase (AR) capable of reducing xylose to xylitol has been identified in S. cerevisiae. The GRE3 gene, encoding the AR enzyme, was deleted in S. cerevisiae CEN.PK2-1C, yielding YUSM1009a. XI from T. thermophilus was produced, and endogenous xylulokinase from S. cerevisiae was overproduced in S. cerevisiae CEN.PK2-1C and YUSM1009a. In recombinant strains from which the GRE3 gene was deleted, xylitol formation decreased twofold. Deletion of the GRE3 gene combined with expression of the xylA gene from T. thermophilus on a replicative plasmid generated recombinant xylose utilizing S. cerevisiae strain TMB3102, which produced ethanol from xylose with a yield of 0.28 mmol of C from ethanol/mmol of C from xylose. None of the recombinant strains grew on xylose.
Aldehyde Reductase↗
Ethanol-modified subcritical water extraction combined with solid-phase microextraction for determining atrazine in beef kidney.
The determination of the levels of pesticides in food products has prompted the development of sensitive and rapid methods of analysis that are solvent-free or utilize solvents that are benign to the environment and laboratory worker. In this study we have developed a novel extraction method that utilizes ethanol-modified subcritical water in combination with solid-phase microextraction (SPME) for the removal of atrazine from beef kidney. In situ sample cleanup was achieved using the technique of matrix solid-phase dispersion. A cross-linked polymer, XAD-7 HP, was utilized as a dispersing material for kidney samples. Subcritical water extractions were performed with a pressurized solvent extraction unit at 100 degrees C and 50 atm. Experimental parameters investigated were the volume of solvent and amount of modifier required for the complete extraction of atrazine and optimization of the extraction time. It was determined that 30% ethanol in water (v/v) is adequate for the complete extraction of atrazine. A Carbowax-divinylbenzene SPME fiber was used to sample the aqueous extracts. Analysis of the fiber contents was by ion-trap GC/MS utilizing the single ion mode. The total time of analysis for a single kidney sample is 90 min. The average percent recoveries from samples spiked to the concentrations of 2 and 0.2 microg/g were 104 and 111, respectively. The average relative standard deviations were 10 and 9, respectively. The method limit of detection for beef kidney spiked with atrazine was found to be 20 ng/g of sample.
Animals↗
Effect of ethanol on the uptake and utilization of nutrients by alcohol-resistant yeasts.
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Biological Transport↗
Effects of chronic ethanol on enzymes regulating sialylation and desialylation of transferrin in rats.
Transferrin is N-glycosylated glycoprotein and plays an important role in iron transport from sites of absorption and storage to sites of utilization. Chronic ethanol alters the normal microheterogeneity pattern of transferrin as a consequence of changes in the sialic acid content. However the underlying basis of this change in sialic acid contents of transferrin in alcohol abuse remains unclear. We have undertaken this study in order to investigate the effects of chronic ethanol in rats with respect to the hepatic rate of (i) transferrin synthesis based on labeled leucine incorporation, (ii) the incorporation of labeled N-acetyl mannosamine (NAM) into sialic acid residues of transferrin, and (iii) roles of specific sialyltransferase and sialidase at hepatic subcellular level. The results showed no significant difference in the incorporation of labeled leucine into transferrin at all levels between the control and ethanol group, whereas the incorporation of NAM into transferrin was significantly decreased by 84% (p < 0.001) both at the whole cell and Golgi level. Thus, the incorporation of labeled NAM relative to the incorporation of labeled leucine into hepatic transferrin was significantly decreased by 86% (p < 0.001) in chronic ethanol-treated animals as compared with the controls both at the whole cell golgi levels. These data are further supported by our finding of concomitant decrease in the activity of beta-galactoside alpha 2,6-sialyltransferase by 58% (p < 0.01) in ethanol-treated rats as compared with control animals.(ABSTRACT TRUNCATED AT 250 WORDS)
Alcoholism↗
Effects of ethanol and temperature on glucose utilization in the in vivo and isolated perfused mouse brain.
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Animals↗
Direct fermentation of potato starch to ethanol by cocultures of Aspergillus niger and Saccharomyces cerevisiae.
Direct fermentation of unhydrolyzed potato starch to ethanol by monocultures of an amylolytic fungus, Aspergillus niger, and cocultures of A. niger and Saccharomyces cerevisiae was investigated. Amylolytic activity, rate and amount of starch utilization, and ethanol yields increased several-fold in coculture versus the monoculture due to the synergistic metabolic interactions between the species. Optimal ethanol yields were obtained in the pH range 5 to 6 and amylolytic activity was obtained in the pH range 5 to 8. Ethanol yields were maximal when fermentations were conducted anaerobically. Increasing S. cerevisiae inoculum in the coculture from 4 to 12% gave a dramatic increase in the rate of ethanol production, and ethanol yields of greater than 96% of the theoretical maximum were obtained within 2 days of fermentation. These results indicate that simultaneous fermentation of starch to ethanol can be conducted efficiently by using cocultures of the amylolytic fungus A. niger and a nonamylolytic sugar fermenter, S. cerevisiae.
Aspergillus niger↗
Isolation of sulfate-reducing bacteria from Tunisian marine sediments and description of Desulfovibrio bizertensis sp. nov.
Several strains of sulfate-reducing bacteria were isolated from marine sediments recovered near Tunis, Korbous and Bizerte, Tunisia. They all showed characteristics consistent with members of the genus Desulfovibrio. One of these strains, designated MB3(T), was characterized further. Cells of strain MB3(T) were slender, curved, vibrio-shaped, motile, Gram-negative, non-spore-forming rods. They were positive for desulfoviridin as bisulfite reductase. Strain MB3(T) grew at temperatures of 15-45 degrees C (optimum 40 degrees C) and at pH 6.0-8.1 (optimum pH 7.0). NaCl was required for growth (optimum 20 g NaCl l(-1)). Strain MB3(T) utilized H(2) in the presence of acetate with sulfate as electron acceptor. It also utilized lactate, ethanol, pyruvate, malate, fumarate, succinate, butanol and propanol as electron donors. Lactate was oxidized incompletely to acetate. Strain MB3(T) fermented pyruvate and fumarate (poorly). Electron acceptors utilized included sulfate, sulfite, thiosulfate, elemental sulfur and fumarate, but not nitrate or nitrite. The G+C content of the genomic DNA was 51 mol%. On the basis of genotypic, phenotypic and phylogenetic characteristics, strain MB3(T) (=DSM 18034(T)=NCIMB 14199(T)) is proposed as the type strain of a novel species, Desulfovibrio bizertensis sp. nov.
DNA, Bacterial↗
[Ethanol formation by methane-utilizing bacteria at ethane co-metabolism].
It was established, that EDTA (1.0 mM) and formamide (100 mM) are inhibitors of methanol dehydrogenase in Methylobacter luteus 12b, Methylomonas rubra 15sh and Methylococcus thermophilus 111p. The investigated strains co-metabolised ethane with the use of formate as the co-substrate. The application of formamide (or EDTA) as inhibitors of methanol dehydrogenase prevented from further transformation of ethanol and resulted in accumulation of extracellular ethanol. It was shown, that M. rubra 15sh accumulated extracellular ethanol under cultivation in a chemostate. The carried out researches have shown a regulation path of co-metabolism process of hydrocarbons by methane utilizing bacteria. Using the specific inhibitors of methanol dehydrogenase and a source of reducing agent (energy) for methane monooxygenase with the help of the cells of methane-oxidizing bacteria it is possible to obtain from ethane or other hydrocarbons the products of their monooxygenation--alcohols.
Ethane↗
Reinterpretation of the pharmacokinetic mechanism of oral benzodiazepine ethanol interaction.
Previously published studies investigating the oral benzodiazepine ethanol interaction have utilized a single dose of ethanol, a single dose of oral benzodiazepine, and measured plasma benzodiazepine concentration over varying time periods. Most studies reported an increase or no change in benzodiazepine plasma concentrations following ethanol administration, which the investigators usually ascribed to an ethanol-induced increase in the benzodiazepine absorption rate constant. However, ethanol decreases the hepatic clearance of benzodiazepines that are biotransformed via the P450 enzyme system and this effect was not taken into account in evaluation of the results of these studies. Computer simulations have been used to investigate possible mechanisms of the oral benzodiazepine-ethanol interaction. The effects of a constant or transient decrease in clearance and an increase in absorption rate constant upon maximum concentration, time of maximum concentration, and area under the benzodiazepine plasma concentration curve (AUC) have been examined. A transient 75% decrease in benzodiazepine clearance resulted in a 13.6% increase in AUC (0-36 hr), a 3.4% increase in Cmax and a 5.7% increase in tmax. These changes are qualitatively consistent with, but quantitatively shy, of those observed in most studies. Consequently, an effect of ethanol upon benzodiazepine absorption must still be considered.
Absorption↗
Involvement of oxygen and mitochondrial function in the metabolism of D-xylulose by Saccharomyces cerevisiae.
Mitochondrial function associated with oxygen was required for growth of Saccharomyces cerevisiae on D-xylulose. The requirement was shown by (i) the inhibition of growth of a wild-type strain under anaerobic conditions, (ii) the inhibition of aerobic growth after treatment with inhibitors of mitochondrial function, and (iii) the lack of aerobic and anaerobic growth of nuclear and cytoplasmic petites. The mitochondrial function was associated with the channeling of catabolites of D-xylulose to growth processes, since ethanol was formed even when growth was inhibited. Mitochondrial function was implicated as well in determining the extent of growth and the concentration of ethanol in aerobic cultures of the wild-type. In such cultures, the concentration of ethanol decreased and growth increased concomitantly as aeration rate increased. A factor in this relation was considered to be the relatively poor ability of D-xylulose to inhibit the oxidative utilization of ethanol.
Anaerobiosis↗
Effects of bicarbonate on intercompartmental reducing-equivalent translocation in isolated parenchymal cells from rat liver.
1. Incubation of isolated liver cells in a medium containing bicarbonate raises malate concentrations almost sixfold compared with values obtained in a bicarbonate-free phosphate medium. The malate concentration of about 0.3mm in bicarbonate medium is of the same order as the K(m) for malate dehydrogenase. 2. The utilization of ethanol, glyercol and sorbitol was increased by 20-35% in bicarbonate medium. 3. Fluoromalate, a specific inhibitor of malate dehydrogenase and the malate carrier, inhibited or ethanol oxidation by 23%, glycerol uptake by 20% and sorbitol uptake by 42% in bicarbonate medium, but had a much smaller inhibitory action in phosphate medium. In consequence fluoromalate almost abolished the stimulatory effects of bicarbonate on substrate utilization. 4. Difluoro-oxaloacetate, a specific inhibitor of aspartate aminotransferase, had about one-half the inhibitory activity of fluoromalate. The two inhibitors in combination were less effective than fluoromalate by itself. 5. It is concluded that bicarbonate stimulates the utilization of reduced substrates, which are oxidized in the cytoplasmic compartment of the liver cell, by increasing the activity of rate-limiting malate dehydrogenase-dependent intercompartmental hydrogen shuttles. Both malate-oxaloacetate and malate-aspartate systems are involved in these hydrogen-translocation processes.
Animals↗
An examination of various mechanisms for ethanol-induced testicular injury: studies utilizing the isolated perfused rat testes.
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Acetaldehyde↗
Reliability of analytical methods for determining anthocyanins in blood orange juices.
Quantitative analysis of anthocyanins was performed on a series of blood orange juices according to various spectrophotometric and HPLC methods, and the causes for different concentration resulting from the application of such procedures were investigated. Spectrophotometric methods utilizing aqueous ethanol as a solvent provided an anthocyanin content higher than that determined by HPLC. Discrepancies were ascribed to the use of impure standards and/or unsuitable calibration lines. The most consistent results with the HPLC findings were obtained by a method utilizing water as a solvent and cyanidin-3-glucoside as a standard. Actual concentration of anthocyanins in blood orange juice was remarkably lower than that currently determined by procedures used in the juice producing factories.
Anthocyanins↗
Tolerance to ethanol-induced hypothermia in adult rats following postnatal ethanol exposure.
Rat pups of both genders were treated during the entire postnatal brain growth spurt (postnatal days 1-20) with ethanol (EE) utilizing an intragastric intubation technique. Two other groups of pups included isocaloric vehicle and handled control pups. Beginning on postnatal day 43 (TD1), and every seventh day subsequently (TD's 2, 3 and 4), the rats received an intraperitoneal dose of 2.2 g/kg ethanol. Their body temperatures were recorded at 0, 30, 60 and 90 minutes postinjection by use of a rectal probe. On the six days between measurements of ethanol-induced hypothermia, all rats were administered a daily dose of ethanol by intragastric intubation. Body growth of male and female pups was inhibited throughout the early treatment period. Body growth of adult females, but not males, was also depressed on TD's 1 and 2. Basal body temperature of EE male rats was selectively depressed at TD2, compared to the other groups. Although all groups showed tolerance to ethanol-induced hypothermia by TD2, there was a significant difference between males and females. Specifically, EE female rats showed a greater degree of tolerance when compared to EE males or control females.
Animals↗
[Ethanol for treatment of delirium in alcohol dependent patients on intensive care units in the Netherlands: efficacy not proven].
OBJECTIVE: To determine the use of ethanol in Dutch intensive care departments (ICUs) for the treatment of deliriant symptoms in alcohol-dependent patients, and to study the literature data concerning this use. DESIGN: Literature search and questionnaire. METHOD: In Medline a search was performed from 1993 onward with keywords 'intensive care' and 'alcohol'/'alcohol withdrawal syndrome'/'delirium'. All Dutch ICUs received a written questionnaire (n = 247) concerning the use of ethanol in this patient group. RESULTS: According to the literature the syndrome is characterized by autonomous hyperactivity, resulting in tachycardia, tachypnoea, hypertension, perspiration, fever, tremors en fear. In delirium caused by alcohol withdrawal benzodiazepines are advised, sometimes in combination with haloperidol. ICUs sometimes use ethanol, although the effectiveness in preventing or treating withdrawal symptoms has never been ascertained in scientific investigations: in a meta-analysis the conclusion is drawn that the studies are too small and insufficiently objective to determine the effectiveness. The response to the questionnaire was 55% (96/176). From all ICUs, 15 (16%) used ethanol occasionally, and treated an estimated 17% of the admitted alcohol-dependent patients. There was a tendency for large ICUs to use ethanol in these patients more frequently. Each ICU used its own method to calculate the required ethanol dosage. Calculation on the basis of these dosages indicated a plasma ethanol concentration of at most 0.5 promille. CONCLUSION: Because only a small percentage of deliriums on ICUs are caused by alcohol withdrawal, and the effectiveness of ethanol in alcohol-dependent patients with a delirium has never been proven, the use of ethanol in such cases is discouraged.
Alcohol Withdrawal Delirium↗