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PubMed2000

Glucose transporters and glucose utilization in rat brain after acute ethanol administration.

In the normal adult brain, glucose provides 90% of the energy requirements as well as substrate for nucleic acid and lipid synthesis. In the present study, effects of ethanol on glucose transporters (GLUT) and glucose utilization were examined in rat brain. Male Sprague-Dawley rats weighing 250-300 gms were given either ethanol 3 gm/kg BW or saline i.p. 4 hrs prior to the animal sacrifice and removal of the cerebral cortical tissue. The cortical plasma membranes analyzed by cytochalasin B binding assay showed a decrease in GLUT number but not in GLUT affinity in the ethanol treated rats as compared to the control rats. The estimated Ro values were 70 +/- 8.9 Vs 91 +/- 8.9 pmoles/mg protein (p < 0.05 N=4) and the estimated Kd values were 0.37 +/- 0.03 and 0.28 +/- 0.05 microM (p: NS) in ethanol and control experiments respectively. Immunoblots of purified cerebral plasma membranes and low density microsomal fraction showed 17% and 71% decrease for GLUTI and 54% and 21% (p<0.05 or less; n=6) for GLUT3 respectively in ethanol treated rats than in control animals. Immunofluoresence studies also showed reduction of GLUT1 immunoreactively in choroid plexus and cortical microvessels of ethanol treated rats as compared to control rats. The effect of ethanol on regional cerebral metabolic rates for glucose (CMR(Glc)) was studied using [6-(14)C] glucose and showed statistically insignificant decrease in brain glucose utilization. These data suggest that ethanol in-vivo decrease GLUT number and protein content in rat cerebral cortex.

Animals↗
PubMed1985

13C NMR studies of butyric fermentation in Clostridium kluyveri.

The fermentation of 13C-labeled ethanol and acetate into butyrate and caproate by Clostridium kluyveri has been studied by using 13C NMR. The pathway involves the conversion of both ethanol and acetate into acetyl coenzymes A, two of which condense to form CoA-linked precursors of butyrate. If butyryl-CoA is involved in the condensation, caproate is the ultimate product. ATP is produced from acetyl-CoA via the reactions catalyzed by phosphotransacetylase and acetate kinase with acetate, a required carbon source, as a co-product. In spectra of whole cells incubated with the labeled carbon sources, label from ethanol appears rapidly in acetate, which then reaches a lower, steady-state concentration due to its re-entry into the pathway. The rapid initial production of acetate indicates equally rapid production of ATP. Label from acetate appears in ethanol only if ethanol is already present, indicating that this process is one of isotopic equilibration rather than net synthesis of ethanol from acetate. The ratio of butyrate to caproate produced depends strongly on the initial ratio of ethanol to acetate in the medium. The relative rates of utilization of ethanol and acetate vary as the fermentation proceeds. 13C-13C coupling in the butyrate and caproate produced from [1-13C]ethanol and [2-13C]acetate can be used to determine if the acetyl-CoA molecules arising from ethanol and acetate enter the same pool or if they remain separated. The data are consistent with random mixing of the acetyl-CoA produced from the two carbon sources.

Acetates↗
PubMed1993

Changes in local cerebral glucose utilization in the awake rat during acute and chronic administration of ethanol.

Local cerebral glucose utilization (LCGU) was measured in 51 structures of the rat brain after acute and/or chronic oral administration of ethanol using the quantitative autoradiographic 2-deoxyglucose method. In the acute experiments, ethanol (3.2 g/kg) was administered via a gastric tube 110 min before the 2-deoxy-D-[1-14C]glucose. The chronic pretreatment was performed using increasing concentrations of ethanol in the drinking water for a period of 20-24 days. The most striking effects on LCGU were seen in the inferior colliculus. Acute and acute plus chronic treatment with ethanol significantly decreased LCGU by 33% and 37%, respectively, whereas chronic treatment significantly increased LCGU by 25%. In general, acute administration of ethanol decreased LCGU in 16 brain structures, particularly of the auditory system. Chronic treatment, besides its effect on the inferior colliculus, only decreased LCGU in the internal capsule. Chronic plus acute administration of ethanol decreased LCGU significantly in 22 structures. It is concluded that an acute oral administration of ethanol has distinct and mainly depressive effects on the functional activity of several brain areas. Chronic administration is less effective.

Administration, Oral↗
PubMed1994

Is the Kluyver effect in yeasts caused by product inhibition?

Candida utilis CBS 621 exhibits the Kluyver effect for maltose, i.e. this yeast can respire maltose and is able to ferment glucose, but is unable to ferment maltose. When glucose was pulsed to a maltose-grown, oxygen-limited chemostat culture of C. utilis, ethanol formation from glucose started almost instantaneously, indicating that the enzymes needed for alcoholic fermentation are expressed in maltose-grown cells. However, the addition of glucose inhibited maltose metabolism. To eliminate a possible catabolite inhibition and/or repression of enzyme activities involved in maltose metabolism, the effect of simultaneously feeding glucose and maltose to an oxygen-limited, maltose-grown chemostat culture was studied. In this case, the glucose concentration in the culture remained below 0.1 mM, which makes glucose catabolite repression unlikely. Nevertheless, maltose metabolism appeared to cease when the culture was switched to the mixed feed. Based on the outcome of the mixed-substrate studies, it was postulated that the Kluyver effect may be caused by feedback inhibition of maltose utilization by ethanol, the product of fermentative maltose metabolism. If ethanol suppresses the utilization of non-fermentable disaccharides, this would provide a phenomenological explanation for the occurrence of the Kluyver effect: accumulation would then not occur and the rate of maltose metabolism would be tuned to the culture's respiratory capacity. This hypothesis was tested by studying growth of C. utilis CBS 621 and Debaryomyces castellii CBS 2923 in aerobic batch cultures on mixtures of sugars and ethanol.(ABSTRACT TRUNCATED AT 250 WORDS)

Candida↗
PubMed1990

Conditioned tolerance provides protection against ethanol lethality.

To produce conditioned drug tolerance, mice were given twice daily injections of 3.5 g/kg of ethanol for four days and were tested on the fifth day in the same environment or in a novel environment. A range of doses of ethanol were utilized on the test day to assess lethality. The LD50 for ethanol was higher in mice tested in the environment previously associated with the administration of ethanol than in those tested in a novel environment. Therefore, conditioned tolerance can provide protection against ethanol lethality.

Animals↗
PubMed1981

Reduction in brain glucose utilization rate after tryptophol (3-indole ethanol) treatment.

3-Indole ethanol has been recently identified as the hypnotic agent in trypanosomal sleeping sickness, and because it is formed in vivo after ethanol or disulfiram treatment, is also associated with the study of alcoholism. When administered intraperitoneally to rats (250 mg/kg) tryptophol induced a sleep-like state that lasted less than an hour (no righting reflex was apparent 2 min after injection, but it returned at 11 min in bovine serum albumin solution, and 47 min in 40% ethanol solution). In ethanol solutions, tryptophol reduced brain cortical glucose utilization by 55% to the basal brain metabolic rate, and this effect lasted less than 1 h. Synergistic effects of tryptophol and ethanol were suggested by the observation that in albumin solution, tryptophol reduced brain glucose utilization by 35%, but a normal rate was not observed until 2 h postinjection.

Animals↗
PubMed2005

Kinetics and thermodynamics of ethanol production by a thermotolerant mutant of Saccharomyces cerevisiae in a microprocessor-controlled bioreactor.

AIMS: The present investigation deals with the development of thermotolerant mutant strain of yeast for studying enhanced productivity of ethanol from molasses in a fully controlled bioreactor. METHODS AND RESULTS: The parental culture of Saccharomyces cerevisiae ATCC 26602 was mutated using UV treatment. A single thermotolerant mutant was isolated after extensive screening and optimization, and grown on molasses medium in liquid cultures. The mutant was 1.45-fold improved than its wild parent with respect to ethanol productivity (7.2 g l-1 h-1), product yield (0.44 g ethanol g-1 substrate utilized) and specific ethanol yield (19.0 g ethanol g-1 cells). The improved ethanol productivity was directly correlated with titres of intracellular and extracellular invertase activities. The mutant supported higher volumetric and product yield of ethanol, significantly (P<or=0.05) higher than the parental and other strains. The mutated cultures produced 1.8- and 2.6-fold more extracellular and intracellular invertase productivity, respectively, than that produced by its wild parent at 40 degrees C. Thermodynamic studies revealed that the cell system exerted protection against thermal inactivation during formation of products. CONCLUSIONS: A mutant derivative of Sacchromyces cerevisiae with improved productivity of ethanol and invertases has been obtained, which showed concomitant improvement in thermostability of endogenous metabolism for formation of both ethanol and invertases. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the present study are of commercial value as the mutant can be used for ethanol production in parts of Pakistan where the temperature may go up to 40 degrees C in April. Ethanol product yield coefficient and volumetric productivity, revealed the hyper-productivity of ethanol from molasses at 40 degrees C, which is not appropriate for wild organism.

Bioreactors↗
PubMed1994

Ethanol from lignocellulosic wastes with utilization of recombinant bacteria.

This article presents the advanced technology that has been developed by BioEnergy International of Gainesville, Florida, utilizing novel recombinant strains of bacteria developed by Lonnie Ingram of the University of Florida. The first commercial applications of these unique fermenting organisms convert 5-carbon sugars, as well as 6-carbon sugars, and oligomers of cellulose (e.g., cellobiose and cellotriose) directly to ethanol. The proposed systems that will be utilized for conversion of agricultural wastes, mixed waste papers, and pulp and paper mill waste in forthcoming commercial installations are now under design. This involves the extensive experience of Raphael Katzen Associates International, Inc. in acid hydrolysis, enzyme production, enzymatic hydrolysis, large-scale fermentation engineering, and distillation/dehydration. Specific examples of this advanced technology will be presented in different applications, namely: 1. Conversion of the hemicellulose content of sugar cane bagasse to 5-carbon sugars by mild-acid prehydrolysis, followed by fermentation of the 5-carbon sugar extract with recombinant Escherichia coli in a commercial installation soon to be under construction in Brazil. This unique process utilizes the surplus hemicellulose fraction of bagasse not required for steam and power generation to produce ethanol, additional to that from the original can juice, which has been converted by conventional sucrose fermentation to ethanol. The process also recovers and converts to ethanol the majority of sucrose normally lost with the bagasse fibers. Resultant beer is enriched in an innovative process to eliminate the need for incremental rectification capacity. 2. Application of this technology to mixed waste paper in Florida, with a moderate loading of newsprint (85% mechanical wood fiber), will involve a mild-acid prehydrolysis, the partial extraction of the 5-carbon sugars produced from hemicellulose as a feedstock for propagation of the recombinant Klebsiella oxytoca bacterium. Included is a facility providing for in-house production of cellulase enzyme, as an active whole broth for direct use in simultaneous saccharification and fermentation (SSF) of the remaining cellulose and residual 5-carbon sugars to ethanol. This is followed by distillation and dehydration in the advanced commercially available low-energy recovery system. 3. Another potential application of this unique technology involves utilization of a variety of wastes from several pulp and paper mills in close proximity, permitting collection of these wastes at low cost and reducing the considerable cost encountered in disposing of such low-energy wet waste.(ABSTRACT TRUNCATED AT 400 WORDS)

Cellulose↗
PubMed1996

Continuous ethanol production from nonsterilized carob pod extract by immobilized Saccharomyces cerevisiae on mineral kissiris using a two-reactor system.

The continuous production of ethanol from nonsterilized carob pod extract by immobilized Saccharomyces cerevisiae on mineral kissiris using one- and two-reactor systems has been investigated. A maximum ethanol productivity of 9.6 g/L/h was obtained at an initial sugar concentration of 200 g/L and D = 0.4 h-1 with 68% of theoretical yield and 34% of sugar utilization using the one-reactor system. At S0 = 200 g/L, D = 0.05 h-1, 83% of theoretical yield, and 64% of sugar utilization, an ethanol productivity of 2.6 g/L/h was achieved. In the two-reactor system, a maximum ethanol productivity of 11.4 g/L/h was obtained at S0 = 200 g/L and D = 0.4 h-1 with 68.5% of theoretical yield and 41.5% of sugar utilization. The two-reactor system was operated at a constant dilution rate of 0.3 h-1 for 60 d without loss of the original immobilized yeast activity. In this case, the average ethanol productivity, ethanol yield (% of theoretical), and sugar utilization were 10.7 g/L/h, 71.5%, and 48%, respectively.

Biotechnology↗
PubMed2000

[Continuous ethanol fermentation using tapioca starch by immobilized yeast cell without carrier].

A widespread interest has been noted in continuous power ethanol fermentation utilizing systems with immobilized yeast cell through self-flocculating. We studied continuous ethanol fermentation by a naturally flocculent strain of Schizosaccharomyces pombe and the performance of two-stage continuous ethanol fermentation system using suspended-bioreactors(total effective volume 1.5 L) has been established: the high biomass levels achieved allow efficient ethanol conversion(72.7 g/L, average), residual glucose(3.74 g/L) and high productivity(9.7 g/L.h) for 150 g/L glucose concentration in feed(tapioca syrup) with average 90% total conversion of substrate. The system was run steadily during a month research.

Bioreactors↗
PubMed1987

In vitro accuracy and precision studies comparing direct and delayed analysis of the ethanol content of vapor.

In vitro accuracy and precision studies were conducted using silica gel, magnesium perchlorate, and indium encapsulation breath collection tubes in conjunction with three infrared breath ethanol analyzers (BAC Verifier, Intoxilyzer 5000, and Intoximeter 3000), the Breathalyzer 900A, and the GC Mark IV. Statistical analyses revealed good accuracy and precision and correlation between direct and delayed vapor ethanol analyses for each combination of instruments and collection devices (range = 0.000 to 0.250 g/210 L, N = 42/instrument, r greater than 0.99). Delayed vapor ethanol analysis utilizing each instrument and collection device combination appears to predict satisfactorily original vapor ethanol concentrations.

Breath Tests↗
PubMed1990

Study on the protoplast fusion between a thermotolerant yeast and Saccharomyces cerevisiae.

Intergenetic protoplast fusion between Saccharomyces cerevisiae 396 and thermotolerant yeast Candida sp. C6 has been studied. 396 is a molasses distiller's yeast, and C6 which was isolated from the hot spring in Yunnan, grows well at 45 degrees C. The auxotrophic mutants of 396 (Arg.) and C6 (Lys.) were obtained by treatment of NTG. The fusion frequency was 0.91 per 10(5) protoplasts. Six fusants were studied, the average size of their cells is 1.3 times the size of their parents, while the DNA content is 1.6 times. Other characteristics of the fusants including colonial and cell morphology, physiology, especially in carbon sources assimilation appeared different. The possibility of heterokaryon formation was excluded except for F2 and F14. The growth curves, efficiency of sugar utilization and ethanol yield of original parents 396 and C6, immediate parents 396 (Arg.) and C6 (Lys.), fusants F1, F7, F12 and F13 have been compared at 28 degrees C, 40 degrees C and 45 degrees C. The intergenetic fusant F13 with efficiency of substrate utilization 94.3% and the final ethanol concentration 59.7 g/l at 40 degrees C has been selected.

Candida↗
PubMed2003

Ethanol effects on local cerebral glucose utilization in high-alcohol-drinking and low-alcohol-drinking rats.

Divergent ethanol-drinking behavior in rats selectively bred for high- or low-ethanol-drinking behavior could be related to differences in the sensitivity of the CNS to ethanol. In the current study, we examined the effects of acute (i.e., single injection) ethanol administration on local cerebral glucose utilization (LCGU) within selected brain regions of high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rats. Adult, male, HAD and LAD rats from replicate line 2 were injected intraperitoneally with saline, or ethanol, at doses of 0.25 g/kg or 1.0 g/kg, during their dark cycle; 10 min later, [14C]-2-deoxyglucose ([14C]-2-DG; 125 microCi/kg) was injected into the femoral vein. Timed arterial blood samples were collected over 45 min and assayed for plasma glucose, ethanol, and [14C]-2-DG levels. Rats were then decapitated, and their brains were quickly extracted and frozen in isopentane at -50 degrees C. Coronal brain sections were prepared and apposed to x-ray film for 2 days, and image densities were determined by using quantitative autoradiography. Data were collected from several key limbic (nucleus accumbens, ventral tegmental area, olfactory tubercle, amygdala, hippocampus, ventral pallidum, and septum), basal ganglia, cortical (medial prefrontal, frontal, parietal, temporal, occipital, entorhinal, piriform, and cingulate), and subcortical (thalamus, habenula, and superior colliculus) structures. After administration of both low (0.25 g/kg) and moderate (1.0 g/kg) doses of ethanol, LCGU values were lower, relative to those for saline controls, in several CNS regions (lateral septum; posterior cingulate, frontal, parietal, and temporal cortices; dorsomedial striatum; and dorsomedial thalamus) of LAD but not HAD rats. These findings may indicate that certain CNS regions of LAD-2 rats are more sensitive than regions of HAD-2 rats to the effects of low-to-intermediate doses of ethanol.

Alcohol Drinking↗
PubMed2002

Aspartate modulates the ethanol-induced oxidative stress and glutathione utilizing enzymes in rat testes.

In order to develop a preventive strategy against ethanol-induced oxidative damages on various tissues and organs, we have examined the protective effect of aspartate on the pathogenesis of testes in the ethanol treated animals. Adult male Sprague-Dawley rats were given ethanol in an amount of 36% of total calories via Lieber-DeCarli liquid diet for 6 weeks without or with aspartate (2 mM in the diet). The control group was pair-fed the diet containing isocaloric dextrin-maltose instead of ethanol. The pathogenesis of testes at post- 6 weeks of experiments were carried out by histochemistry and biochemical parameters for oxidative stress such as the level of thiobarbituric acid reactive substances (TBARS) and the activities of glutathione utilizing enzymes were also examined. Chronic ethanol administration resulted in the increased amount of thiobarbituric acid reactive substances (TBARS) in the testes, which was significantly lessened by concurrent aspartate treatment (p < 0.05). In addition to this, liver function test indicated by alkaline phosphatase activity in serum showed that the ethanol-induced hepatotoxicity was significantly ameliorated by aspartate administration. And the activities of glucose-6-phosphate dehydrogenase and glutathione transferase in testis cytosol were decreased in the ethanol treated rats (p < 0.01 and < 0.005, respectively). These data suggest that aspartate may attenuate the ethanol-induced oxidative tissue damage in rat testes possibly through a redox-related protective effect on peroxidation.

Animals↗
PubMedDate not supplied

[Anatomo-histological and histochemical study of acute lesions of the gastroduodenal mucosa, produced by ethanol, before and after truncal vagotomy plus pyloroplasty in rats].

The anatomo-pathologic alterations determined by ethanol in the gastroduodenal mucosa of rats are studied, as well as its action about truncal vagotomy plus pyloroplasty (VT + P). We use albino rats submitted to the administration of ethanol, 33% --via orogastric catheter- and to truncal vagotomy plus pyloroplasty, as well the association of the 2 variants. The utilization of ethanol, according to the up to date methodology, can be confirmed by a simple experimental production method of acute ulcer in rats. The VT + P determined acute ulcers in the 24 hour observation group, besides acute inflammatory lesions and with the decrease of mucins, diffusively, in the gastroduodenal mucosa. The performance of VT + P, 2 hours after the administration of ethanol, period in which the lesions are entirely settled, determined and aggravation of the gastric lesions through the increase of the media ulcerous gastric area and its histological aspects. On the other hand, the performance of VT + P, followed by the administration of ethanol 2 hours after, also determined an aggravation of gastric lesions, according to the same former parameters. When it was the time to perform the VT + P, 10 days before the administration of ethanol, or the inverse, a small reduction at the ulcerous gastric area had accrued but it did not amount to much. There was not a characterization of preventive effects or curative of this surgical procedure considering the gastric lesions produced by ethanol, but there was characterization of aggravating effect. All the possible hypothesis to the aggravation of these lesions are also discussed with the utilization of VT + P, as well its clinical use on the human being.

Animals↗
PubMed2005

Perspectives on bioenergy and biotechnology in Brazil.

Brazil is one of the world's largest producers of alcohol from biomass at low cost and is responsible for more than 1 million direct jobs. In 1973, the Brazilian Program of Alcohol (Proalcool) stimulated the creation of a bioethanol industry that has led to large economic, social, and scientific improvements. In the year 1984, 94.5% of Brazil's cars used bioethanol as fuel. In 2003/2004, 350.3 million of sugarcane produced 24.2 million t of sugar and 14.4 billion L of ethanol for an average 4.3 million cars using ethanol. Since its inception, cumulative investment in Proalcool totals US$11 billion, and Brazil has saved US$27 billion in oil imports. The ethanol production industry from sugarcane gene-rates 152 times more jobs than would have been the case if the same amount of fuel was produced from petroleum, and the use of ethanol as a fuel is advantageous for environmental reasons. In 2003, one of the biggest Brazilian ethanol industries started consuming 50% of the residual sugarcane bagasse to produce electrical energy (60 MW), a new alternative use of bioenergy for the Brazilian market. Other technologies for commercial uses of bagasse are in development, such as in the production of natural fibers, sweeteners (glucose and xylitol), single-cell proteins, lactic acid, microbial enzymes, and many other products based on fermentations (submerged and semisolid). Furthermore, studies aimed at the increase in the biosynthesis of sucrose and, consequently, ethanol productivity are being conducted to understand the genetics of sugarcane. Although, at present, there remain technical obstacles to the economic use of some ethanol industry residues, several research projects have been carried out and useful data generated. Efficient utilization of ethanol industry residues has created new opportunities for new value-added products, especially in Brazil, where they are produced in high quantities.

Biotechnology↗
PubMed1986

Alcohol and nutrition: caloric value, bioenergetics, and relationship to liver damage.

Alcoholic beverages contribute an appreciable percentage (4-6%) to the total caloric intake in Western societies. The caloric value of ethanol as fuel may be dose-related. Most evidence suggests that at moderate intake levels of less than 45 g/day (3 drinks) ethanol is efficiently utilized as a fuel by the liver. At high intakes, ethanol calories may not be utilized for cellular synthesis of ATP and maintenance of weight. The exact mechanism for this inefficient utilization remains unknown but may be related, in part, to metabolism of ethanol by the microsomal ethanol-oxidizing system, a reaction that does not contribute to generation of reducing equivalents for ATP synthesis. Although ethanol is utilized for ATP synthesis after single-dose administration, chronic consumption leads to morphological changes in hepatic mitochondria and to decreased ATP synthesis. Reductions in the activities of the enzymes of the mitochondrial electron transport chain have been reported after alcohol feeding and may help to explain decreases in hepatic ATP synthesis. There is some evidence that ATP degradation by "Na-K ATPase" is increased after ethanol feeding and that hepatic O2 consumption is likewise enhanced. However, other studies have failed to demonstrate enhanced O2 consumption. Current evidence suggests that malnutrition alone is not sufficient to explain the pathogenesis of chronic liver disease in alcoholics. Although the daily amount of alcohol consumed and the duration of excessive consumption are clearly important factors in the development of alcoholic hepatitis and cirrhosis, other factors, particularly nutritional deficiencies, may modulate the risk of developing alcohol-related liver damage. The prevalence of malnutrition is exceedingly high in alcoholics with clinically severe liver disease. Nutritional deficiencies are better correlated with a clinical index of severity than with histologic severity of alcoholic hepatitis. Prognosis and outcome of patients with alcoholic liver disease may be affected by nutritional deficiencies, which thus provides a rationale for aggressive nutritional management of these patients.

Acetaldehyde↗