SEARCH · Search PubMed

Results for “Ethanol utilization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed1983

Acute effects of ethanol in the control of protein synthesis in isolated rat liver cells.

The acute effect of ethanol on hepatic protein synthesis is a rather controversial issue. In view of the conflicting reports on this subject, the effect of ethanol on protein labeling from L-[3H]valine in isolated liver cells was studied under a variety of experimental conditions. When tracer doses of the isotope were utilized, ethanol consistently decreased the rate of protein labeling, regardless of the metabolic conditions of the cells. This inhibition was not prevented by doses of 4-methylpyrazole large enough to abolish all the characteristic metabolic effects of ethanol, and it was not related to perturbations on the rates of L-valine transport and/or proteolysis. When ethanol was tested in the presence of saturating doses of L-[3H]valine no effect on protein labeling was observed. These observations suggest that the ethanol effect in decreasing protein labelling from tracer doses of the radioactive precursor does not reflect variations in the rate of protein synthesis but reflects changes in the specific activity of the precursor. These changes probably are secondary to variations in the dimensions of the amino acid pool utilized for protein synthesis. Even though it showed a lack of effect when tested alone, in the presence of saturating doses of the radioactive precursor ethanol inhibited the stimulatory effects on protein synthesis mediated by glucose and several gluconeogenic substrates. This effect of ethanol was not prevented by inhibitors of alcohol dehydrogenase, indicating that a shift of the NAD system to a more reduced state is not the mediator of its action. It is suggested that ethanol probably acted by changing the steady-state levels of some common effector(s) generated from the metabolism of all these fuels or else by preventing the inactivation of a translational repressor.

Animals↗

PubMed1984

Interrelationships between the metabolic effects of glucagon and ethanol in the perfused mouse liver.

Effects of glucagon and ethanol on hepatic metabolism were examined with in situ perfused livers from fasted Swiss albino mice. In the absence of added gluconeogenic substrate, the presence of glucagon with ethanol effectively restored hepatic glucose production to a rate found with livers perfused with the hormone alone. When lactate was added to the perfusate, the presence of ethanol almost completely suppressed glucose formation but glucagon only partially overcame this inhibition. Ethanol and/or glucagon inhibited hepatic alpha-amino acid N release both in the absence and presence of added gluconeogenic substrate. Ketone body formation was increased three-fold when both glucagon and ethanol were added together to the medium of livers perfused in the absence of exogenous gluconeogenic precursor, yet neither agent alone had an effect. Ethanol utilization by the perfused liver was markedly inhibited by glucagon in the absence of added lactate. The presence of exogenous lactate also decreased ethanol removal by the liver and the addition of glucagon with lactate diminished ethanol clearance further. Thus, interrelationships between the consequences of glucagon and ethanol on hepatic metabolism have been delineated in the perfused mouse liver.

Animals↗

PubMed2006

The effect of ethanol, ethanol metabolizing enzyme inhibitors, and Vitamin E on regulating glutathione, glutathione S-transferase, and S-adenosylmethionine in mouse primary hepatocyte.

We studied changes in the antioxidant systems involved in hepatoprotection after ethanol exposure in primary culture of mouse hepatocytes. Ethanol decreased glutathione (GSH) levels and the S-adenosylmethionine (SAMe) to S-adenosylhomocysteine (SAH) ratio by 53% and 22%, respectively. Cytosolic glutathione S-transferase (GST) activity was significantly lower in ethanol exposed hepatocytes, which was accompanied by an increase in GST activity in the culture medium. When specific substrates for mu- and pi-class GST were utilized, ethanol significantly decreased the mu- and pi-class GST activity by 53% and 13%, respectively. Lipid peroxidation (LPO), assessed by the thiobarbituric acid assay, increased to 221% of control by ethanol and was potentiated by cyanamide, an aldehyde dehydrogenase inhibitor. The changes in LPO, cytosolic GST activity, GSH levels and SAMe/SAH ratio in ethanol exposed hepatocytes were completely or partially reversed by either Vitamin E or 4-methylpyrazole, an alcohol dehydrogenase (ADH) inhibitor. Retinoid X receptor alpha-deficient (RXRalpha KO) mice, which are more susceptible to ethanol-induced liver toxicity, have decreased pi-class GST (56%), mu-class GST (28%), and glutathione peroxidase (35%) activities compared with wild type. Taken together, primary hepatocyte provides a valuable model to analyze ethanol-induced oxidative stress. The inhibition of mu-class GST activity by ethanol and the decreased pi-class GST activity in RXRalpha KO mice implicate the importance of these isozymes in ethanol detoxification process.

Journal Article↗

PubMed2006

Functional analysis of alcS, a gene of the alc cluster in Aspergillus nidulans.

The ethanol utilization pathway (alc system) of Aspergillus nidulans requires two structural genes, alcA and aldA, which encode the two enzymes (alcohol dehydrogenase and aldehyde dehydrogenase, respectively) allowing conversion of ethanol into acetate via acetyldehyde, and a regulatory gene, alcR, encoding the pathway-specific autoregulated transcriptional activator. The alcR and alcA genes are clustered with three other genes that are also positively regulated by alcR, although they are dispensable for growth on ethanol. In this study, we characterized alcS, the most abundantly transcribed of these three genes. alcS is strictly co-regulated with alcA, and encodes a 262-amino acid protein. Sequence comparison with protein databases detected a putative conserved domain that is characteristic of the novel GPR1/FUN34/YaaH membrane protein family. It was shown that the AlcS protein is located in the plasma membrane. Deletion or overexpression of alcS did not result in any obvious phenotype. In particular, AlcS does not appear to be essential for the transport of ethanol, acetaldehyde or acetate. Basic Local Alignment Search Tool analysis against the A. nidulans genome led to the identification of two novel ethanol- and ethylacetate-induced genes encoding other members of the GPR1/FUN34/YaaH family, AN5226 and AN8390.

Alcohol Dehydrogenase↗

PubMed1988

Ethanol tolerance and the induction of stress proteins by ethanol in Candida albicans.

Ethanol is one of the products of the metabolism of glucose by Candida albicans. The amount produced is directly related to the concentration of glucose in the medium. The fungus utilizes ethanol as a sole source of carbon but is relatively intolerant of ethanol in its environment. Ethanol induces germ tube formation by blastoconidia of C. albicans. Germination was not seen under fermentation conditions even though the amount of ethanol produced was in the range form stress proteins that are similar to heat shock proteins. The possibility that stress proteins may regulate germ tube formation by C. albicans is discussed.

Autoradiography↗

PubMed1976

Mechanism of the stimulatory effect of fructose on ethanol oxidation in perfused rat liver.

The stimulatory effect of fructose on ethanol oxidation was studied in livers from fasted rats perfused with Krebs-Henseleit-bicarbonate buffer in a non-recirculating system. Two series of experiments were performed: (A) ethanol was infused with stepwise increasing concentrations (0.1-20 mM) in the presence of 4 mM fructose; (B) fructose was infused with stepwise increasing concentrations (0.5-10 mM) in the presence of 2 mM ethanol. From measured metabolic rates the following parameters were calculated: energy-rich phosphates consumed for fructose metabolism which were provided from oxidative phosphorylation (delta approximately P); reducing equivalents derived from stimulated ethanol utilization which were disposed by mitochondrial oxidation (delta2H). Under the various conditions studied a linear relationship between these parameters was observed. The ratio delta approximately P/delta2H was about 2.0. It is suggested that fructose stimulates ethanol oxidation indirectly by increasing the energy consumption of the liver due to the production of glucose from fructose. Consequetnly, the rate of oxidative phosphorylation is increased and, therefore, the capacity of the respiratory chain for oxidizing reducing equivalents derived from ethanol is enhanced. The data support the more general hypothesis that the rate of ethanol oxidation depend upon the rate of hepatic energy consumption in a given metabolic state.

Alcohol Oxidoreductases↗

PubMed2005

A wide host-range metagenomic library from a waste water treatment plant yields a novel alcohol/aldehyde dehydrogenase.

Using DNA obtained from the metagenome of an anaerobic digestor in a waste water treatment plant, we constructed a gene library cloned in the wide host-range cosmid pLAFR3. One cosmid enabled Rhizobium leguminosarum to grow on ethanol as sole carbon and energy source, this being due to the presence of a gene, termed adhEMeta. The AdhEMeta protein most closely resembles the AdhE alcohol dehydrogenase of Clostridium acetobutylicum, where it catalyses the formation of ethanol and butanol in a two-step reductive process. However, cloned adhEMeta did not confer ethanol utilization ability to Escherichia coli or to Pseudomonas aeruginosa, even though it was transcribed in both these hosts. Further, cell-free extracts of E. coli and R. leguminosarum containing cloned adhEMeta had butanol and ethanol dehydrogenase activities when assayed in vitro. In contrast to the well-studied AdhE proteins of C. acetobutylicum and E. coli, the enzyme specified by adhEMeta is not inactivated by oxygen and it enables alcohol to be catabolized. Cloned adhEMeta did, however, confer one phenotype to E. coli. AdhE- mutants of E. coli fail to ferment glucose and introduction of adhEMeta restored the growth of such mutants when grown under fermentative conditions. These observations show that the use of wide host-range vectors enhances the efficacy with which metagenomic libraries can be screened for genes that confer novel functions.

Alcohol Dehydrogenase↗

PubMed1975

Giant cells from Saccharomyces uvarum grown after x-irradiation.

Yeast cells, Saccharomyces uvarum, were irradiated with X-rays and grown in liquid suspension. Glucose as the only carbon source was limited to 12.5 mM. Under these conditions giant cells are formed. Cell number, glucose utilization, ethanol production and oxygen consumption are measured during the time of growth. The mean weight of single cells in the stationary phase increases up to 75 krad and is not due to an uptake of water. In irradiated cultures oxygen consumption and glucose utilization per cell are higher than in control cells. The data demonstrate that synthesis- and energy-metabolism during the formation of non-dividing, radiation-induced giant cells is increased.

Ethanol↗

PubMed2000

Effect of ethanol on the production of carboxypeptidase Y using the GAL10 promoter in a Saccharomyces cerevisiae gal80 mutant.

In the course of studying carboxypeptidase Y (CPY) production, we found that the expression level of the gene, which is under the control of the GAL10 promoter, increased in a Saccharomyces cerevisiae gal80 mutant grown in a medium containing ethanol as the sole carbon source. In the cultivation of the gal80 mutant KS58-2D/pCY303 carrying a multicopy plasmid, which contains the PRC1 gene fused to the GAL10 promoter, CPY production continued after the consumption of galactose. In this phase, the cells utilized ethanol as the carbon source. To increase the CPY production level, we examined the effect of carbon source feeding in a fed-batch culture. The production level in the fed-batch culture using ethanol was 1.3-fold higher than that in a batch culture and 1.6-fold higher than that in a fed-batch culture using galactose. By 5'-deletion analysis of the GAL10 promoter, the region between -256 and -232 was found to be important for the promoter activity in the gal80 mutant growing in the presence of ethanol.

Journal Article↗

PubMed2003

Onset of carbon catabolite repression in Aspergillus nidulans. Parallel involvement of hexokinase and glucokinase in sugar signaling.

The role of hexose phosphorylating enzymes in the signaling of carbon catabolite repression was investigated in the filamentous fungus Aspergillus nidulans. A d-fructose non-utilizing, hexokinase-deficient (hxkA1, formerly designated frA1) strain was utilized to obtain new mutants lacking either glucokinase (glkA4) or both hexose kinases (hxkA1/glkA4). d-Glucose and d-fructose phosphorylation is completely abolished in the double mutant, which consequently cannot grow on either sugar. The glucokinase single mutant exhibits no nutritional deficiencies. Three repressible diagnostic systems, ethanol utilization (alcA and alcR genes), xylan degradation (xlnA), and acetate catabolism (facA), were analyzed in these hexose kinase mutants at the transcript level. Transcriptional repression by d-glucose is fully retained in the two single kinase mutants, whereas the hexokinase mutant is partially derepressed for d-fructose. Thus, hexokinase A and glucokinase A compensate each other for carbon catabolite repression by d-glucose in the single mutants. In contrast, both d-glucose and d-fructose repression are severely impaired for all three diagnostic systems in the double mutant. Unlike the situation in Saccharomyces cerevisiae, the hexose phosphorylating enzymes play parallel roles in glucose repression in A. nidulans.

Acetate-CoA Ligase↗

PubMed1994

Aspects of glucose uptake in Saccharomyces cerevisiae.

A wild-type Saccharomyces cerevisiae strain showed simple saturation kinetics for glucose uptake, with a Km of 4 mM when cells were obtained from exponential growth on glucose, and a similar, single Km of 2 to 8 mM was found under a variety of other growth conditions. Later in growth on glucose, and during ethanol utilization, a second kinetic component was observed, which might reflect either artifacts of membrane alteration or a Km in the molar range.

Biological Transport↗

PubMed1992

Effects of ethanol on glucose utilization by cultured mammalian embryos.

We have previously observed correlations between placental glucose transfer and growth of fetuses of ethanol (EtOH)-fed and control rats. In the present study, whole mammalian embryos were used to define the interaction of glucose supply and the effects of EtOH on growth and differentiation. Rat embryos were cultured in 75% normal rat serum from day 9.5 to day 11.5 of gestation. EtOH produced dose-dependent reductions of embryo protein content (mean +/- SEM = 212 +/- 5, 171 +/- 11, 141 +/- 16, and 113 +/- 9 micrograms/embryo in the presence of 0, 25, 50, and 100 mM EtoH, respectively). Somite number was 25.7 +/- 0.3, 23.4 +/- 0.7, 21.8 +/- 0.7, and 21.1 +/- 0.4 under the same conditions. Exposure to ethanol during the first 24 hr in culture decreased embryo protein content to the same extent as exposure for the entire 48-hr culture period. After 46 hr in culture, control and ethanol-exposed embryos were incubated with 14C-glucose for 2 hr. Ethanol produced dose-dependent reductions of CO2 production, anabolic utilization, lactate release, and total glucose utilization. Glucose supplementation (300 mg/dl) significantly increased embryo protein content and each of these glucose utilization parameters. When glucose utilization was expressed relative to embryo protein content, incorporation of the label into embryonic tissues was significantly reduced by ethanol and increased by glucose supplementation. Embryo protein content correlated closely (r = 0.871, p less than 0.0001) with anabolic glucose utilization. Thus, ethanol directly affects embryo glucose utilization, both as an energy source and as a synthetic substrate, in addition to its effects on placental glucose transfer.

Animals↗

PubMed2001

The transcriptional activator Cat8p provides a major contribution to the reprogramming of carbon metabolism during the diauxic shift in Saccharomyces cerevisiae.

In yeast, the transition between the fermentative and the oxidative metabolism, called the diauxic shift, is associated with major changes in gene expression and protein synthesis. The zinc cluster protein Cat8p is required for the derepression of nine genes under nonfermentative growth conditions (ACS1, FBP1, ICL1, IDP2, JEN1, MLS1, PCK1, SFC1, and SIP4). To investigate whether the transcriptional control mediated by Cat8p can be extended to other genes and whether this control is the main control for the changes in the synthesis of the respective proteins during the adaptation to growth on ethanol, we analyzed the transcriptome and the proteome of a cat8 Delta strain during the diauxic shift. In this report, we demonstrate that, in addition to the nine genes known as Cat8p-dependent, there are 25 other genes or open reading frames whose expression at the diauxic shift is altered in the absence of Cat8p. For all of the genes characterized here, the Cat8p-dependent control results in a parallel alteration in mRNA and protein synthesis. It appears that the biochemical functions of the proteins encoded by Cat8p-dependent genes are essentially related to the first steps of ethanol utilization, the glyoxylate cycle, and gluconeogenesis. Interestingly, no function involved in the tricarboxylic cycle and the oxidative phosphorylation seems to be controlled by Cat8p.

Carbon↗

PubMed2003

Ethanol fixation of lymphoma samples as an alternative approach for preservation of the nucleic acids.

Molecular methods play an important role in diagnostic pathology of lymphomas. PCR based demonstration of clonality or detection of a specific chromosomal translocation may determine the exact classification of the lymphoma. Hence the final diagnosis may depend on the quality of preserved nucleic acids in the bioptic specimen. The integrity of DNA and RNA may be damaged by formalin fixation, which destroys the nucleic acids by fragmentation. Therefore, a portion of each lymphoma sample should be frozen. To substitute freezing techniques we utilized ethanol as a fixative, which preserves nucleic acids. We compared PCR and RT-PCR products from lymphoma samples, which were differently pre-treated by ethanol fixation, formalin fixation and freezing. The ethanol fixed samples retained a high quality of both DNA and RNA and provided reproducible PCR products similar to frozen samples and significantly better then those extracted from formalin fixed samples. We may recommend ethanol as a complementary fixative for all pathology laboratories where deep freezing in not routinely available.

Biomarkers, Tumor↗

PubMed2001

Effects of aflastatin A, an inhibitor of aflatoxin production, on aflatoxin biosynthetic pathway and glucose metabolism in Aspergillus parasiticus.

Aflastatin A inhibits aflatoxin production by Aspergillus parasiticus via an unknown mechanism. We found that aflastatin A clearly inhibited production of norsolorinic acid, an early biosynthetic intermediate of aflatoxin, at a concentration of 0.25 microg/ml. Reverse-transcriptase polymerase chain reaction (RT-PCR), and real-time quantitative PCR (TaqMan PCR) experiments indicated that the transcription of genes encoding aflatoxin biosynthetic enzymes (pksA, ver-1, and omtA) and a gene encoding a regulatory protein for expression of the biosynthetic enzymes (aflR) were significantly reduced by the addition of aflastatin A. We also found that aflastatin A elevated the glucose consumption and ethanol accumulation by A. parasiticus, and repressed transcription of genes involved in ethanol utilization. These results suggest that aflastatin A inhibits a very early step in aflatoxin biosynthesis prior to the transcription of aflR and can influence glucose metabolism in the fungus.

Aflatoxins↗

PubMed2001

Frequency of oral mucosa micronuclei in gas station operators after introducing methanol.

Methanol has been proposed in different countries as an alternative automotive fuel to be used as an additive to, or replacement for, gasoline or ethanol. Utilization of methanol is increasing exposure to low levels of methanol vapors in the environment and more specifically in occupational settings such as gas stations. Pump operators are exposed to relatively high levels of fuel vapors, the consequences of which have not been fully examined. In this study, the micronucleus assay in squamous oral cells was performed on pump operators of 28 gas stations in three different periods in the city of São Paulo, Brazil. The frequency of micronuclei (MN) was evaluated before and 1 year after a mixed fuel called MEG, which contains 33% methanol, 60% ethanol and 7% gasoline, was introduced. The third evaluation, 3 years later, represents a period where the number of cars using alcohol fuel had decreased drastically and the pump operator exposure to MEG became very low. The frequency of MN observed in 76 employees in 1992 (mean = 3.62 +/- 0.39) was significantly increased (P < 0.001) as compared with 76 operators exposed in 1989 (mean = 1.41 +/- 0.26) and 129 exposed in 1995 (mean = 1.20 +/- 0.15). These differences were also significant when compared with control groups not exposed professionally to motor fuel. These findings could indicate a mutagenic hazard of the MEG occurring in those with occupational exposure.

Adult↗

PubMed1976

Effect of crotonaldehyde on the metabolism of Candida utilis during the production of single cell protein from ethanol.

The effect of 20 low-boiling compounds on the yeast Candida utilis 49 was assessed by a screening test on agar medium. The highest toxicity was exhibited by crotonaldehyde, allyl alcohol and acrolein. Oxidation and assimilation experiments in a slightly aerobic environment showed that an increase in the level of crotonaldehyde in the medium in the range of 10--20 mg 1-1 brings about a lowering of intensity of metabolic processes in Candida utilis, suppression of ethanol utilization and aerobic oxidation rate, a drop in biomass yield, prolongation of cultivation time, etc. The inhibitory effect of crotonaldehyde depends strongly on the manner of its dosage into the medium (single or continuous) and other cultivation conditions (intensity of medium aeration, physiological state of the culture, etc). Crotonaldehyde is lost from the medium partially by volatilization and partially due to chemical and biochemical transformation.

Acetaldehyde↗

PubMed2000

Polytomella spp. growth on ethanol. Extracellular pH affects the accumulation of mitochondrial cytochrome c550.

A defined medium with ethanol as sole carbon source was devised for growth of the colorless, unicellular alga Polytomella spp. Cell density on this carbon source was related to extracellular pH. An acidic pH was required for ethanol utilization; best yields were obtained at pH 3.7. Spectroscopic analysis of the cells showed that the concentration of cytochrome c per cell was 40% higher than at pH 6.0; the concentrations of cytochrome a606 (cytochrome c oxidase) and b566 (cytochrome bc1 complex) were the same. A soluble cytochrome c550 was purified from cells grown at pH 3.7 and characterized by peptide sequencing as the 12-kDa cytochrome c550 of the mitochondrial respiratory chain. Immunoblots of total cell proteins showed higher accumulation of cytochrome c550 at pH 3.7 than at pH 6.0. RNA blot analysis gave clear evidence of the abundance of c550 transcript in cells grown at pH 3.7. The amount of mitochondrial proteins obtained from cells grown at pH 3.7 was twofold higher than that of cells grown at pH 6.0. Mitochondria isolated from both cell types readily oxidized succinate, malate or ethanol. The rates of oxygen uptake were 20-25% higher in mitochondria from cells grown at pH 3.7. Cyanide and antimycin A inhibited respiration with succinate up to 95% in both types of mitochondria. The participation of cytochrome c550 in mitochondrial electron transport from succinate to oxygen was shown by spectral measurements.

Amino Acid Sequence↗