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PubMed1975

Study of indirect methods for measuring hepatic blood flow in the isolated perfused dog liver.

This study was undertaken to assess the reliability of the constant infusion clearance and extraction technique (CIT) and the single injection clearance method (SIT), to measure hepatic perfusate flow at different levels of liver function. In the 36 isolated perfused dog livers, hepatic perfusate flow(HPF) was monitored by a direct method (DM), and the HPF was simultaneously measured with an indirect method (IM) utilizing bromosulphophthalein BSP) as indicator (20 SIT and 16 SIT). In 16 experiments, absolute ethanol (750 mM) and sodium taurocholate (600 muM) were seperately utilized to impair BSP metabolism. By comparison with DM, in the experiments with an extraction ratio(ER) of BSP lower than 10%, the error of the IM (ml/min) was for the CIT 154.57 +/- 46.55 and for the SIT 107.25 +/- 34.20. This error was significantly greater than in the experiments with an ER greater than 10% (CIT 15.70 +/- 3.88, SIT 8.20 +/- 1.38) p less than 0.01. In the studies with ER less than 10%, no difference was found in the error detected with the SIT (107 +/- 34.20) and CIT measurements (154.37 +/- 46.55); in the experiments with an ER greater than 10%, the error with the CIT (15.70 +/- 3.88) was greater than the one attained with the SIT (8.20 +/- 1.38, p less than 0.10 greater than 0.05). It is concluded that both methods are reliable techniques, for measuring HPF in livers with normal or near normal clearance capacity, but even in these ideal experimental conditions the values for HPF are inacurate when the liver clearance function is moderate or severly impaired.

Animals↗
PubMedDate not supplied

[The evaluation of a new complement fixation microtechnic (Garcia & Sotelo, 1991) for the diagnosis of chronic Chagas disease with different antigenic preparations].

From this present data it has been evaluated a new complement fixation test, comparatively to indirect immunofluorescence to diagnose chronic Chagas' disease, utilizing one watery extract of epimastigotes of Trypanosoma cruzi and three other ethanolic extracts: one from epimastigotes, one from tripomastigotes and a third one of amastigotes obtained from cultures. Utilizing 236 serum samples indirect immunofluorescence test was performed: 109 positives (20 of them with positive parasitologic diagnostic) and 127 negatives (96 of healthy blood donors and 31 with other diseases). The results have showed that is possible a positive reaction in diluted samples up to 1:16. The best limits of reactivity found were the dilutions 1:4 for the ethanolic extract of amastigotes and 1:2 for the others antigens. The correlation index among the new complement fixation test and indirect immunofluorescence test showed that the ethanolic extract from epimastigotes was the best antigen to be utilized to diagnosis purposes. Its co-positivity index with indirect immunofluorescence was 0.92207 and the co-negative index was 0.90000. Concluding, the new complement fixation test showed itself as a fast, sensible, easily applicable semiquantitative microtechnique to the diagnosis of chronic Chagas' disease.

Animals↗
PubMed2003

A modified Saccharomyces cerevisiae strain that consumes L-Arabinose and produces ethanol.

Metabolic engineering is a powerful method to improve, redirect, or generate new metabolic reactions or whole pathways in microorganisms. Here we describe the engineering of a Saccharomyces cerevisiae strain able to utilize the pentose sugar L-arabinose for growth and to ferment it to ethanol. Expanding the substrate fermentation range of S. cerevisiae to include pentoses is important for the utilization of this yeast in economically feasible biomass-to-ethanol fermentation processes. After overexpression of a bacterial L-arabinose utilization pathway consisting of Bacillus subtilis AraA and Escherichia coli AraB and AraD and simultaneous overexpression of the L-arabinose-transporting yeast galactose permease, we were able to select an L-arabinose-utilizing yeast strain by sequential transfer in L-arabinose media. Molecular analysis of this strain, including DNA microarrays, revealed that the crucial prerequisite for efficient utilization of L-arabinose is a lowered activity of L-ribulokinase. Moreover, high L-arabinose uptake rates and enhanced transaldolase activities favor utilization of L-arabinose. With a doubling time of about 7.9 h in a medium with L-arabinose as the sole carbon source, an ethanol production rate of 0.06 to 0.08 g of ethanol per g (dry weight). h(-1) under oxygen-limiting conditions, and high ethanol yields, this yeast strain should be useful for efficient fermentation of hexoses and pentoses in cellulosic biomass hydrolysates.

Arabinose↗
PubMed1984

Temporal changes in plasma levels and metabolism of ketone bodies by liver and brain after ethanol and/or starvation in C57BL/6J mice.

The effects of ethanol and starvation on ketone body production and utilization were investigated. In the first experiment, adult C57BL/6J mice were divided into four groups: (i) control (fed); (ii) starvation (up to 31 h); (iii) ethanol (acute 5 g/kg i.p.); (iv) ethanol (ETOH) + starvation. Plasma ketone body (KB) concentrations in control mice remained constant at approx. 0.37 mM. The levels of KBs in starved mice began to increase at about 7 h and rose to a peak of 2.5 mM at about 24 h, then fell to 1.8 mM at 31 h. The levels in mice treated with ETOH began to rise soon after injection, reached 1.5 mM at 10 h, and returned to control levels by 15 h. Although there was no difference in elevated levels of KBs between two groups of mice treated with ETOH plus starvation and ETOH alone at 7-10 h, the level continued to rise steadily to 2.0 mM through 31 h in the former group. At 10 h post ETOH, mice either fed ad lib. or fasted had increased hepatic capacity to synthesize acetoacetate (AcAc) from palmitate; this effect was prolonged and enhanced by continued fasting for 24 h. In the brain, the rate of AcAc oxidation was twice that for beta-hydroxybutyrate (beta OHB) and glucose. Neither ETOH nor starvation affected energy production from KB and glucose. AcAc was also utilized for fatty acid synthesis and the rate of synthesis was stimulated by ETOH at 10 h after injection. The rate of lipogenesis from beta OHB accounted for less than 10% of that from AcAc. Together these experiments demonstrate that ETOH increases both hepatic ketone production and plasma KB levels for at least 10 h. ETOH alone led to elevated KB levels long before the rise due to starvation. In brain, at 10 h, an increased capacity to utilize AcAc for lipogenesis was found. The results indicate that ETOH through the production of KBs could provide an important source of energy and lipid precursors for the brain of mice.

Alcohol Drinking↗
PubMed2001

Effect of long-term ethanol feeding on brainstem alpha(2)-receptor binding in Wistar-Kyoto and spontaneously hypertensive rats.

Our previous studies have shown that ethanol attenuates baroreflex function in Wistar-Kyoto (WKY) but not in spontaneously hypertensive rats (SHRs). The present study determined the effects of chronic ethanol administration on alpha(2)-binding sites in brainstem areas that modulate baroreflexes. In vitro autoradiography was utilized to evaluate the effect of a 3-month ethanol feeding on the density (B(max)) and affinity (K(D)) of alpha(2)-adrenoceptors in the middle (mNTS) and rostral (rNTS) portions of the nucleus tractus solitarius of SHRs and WKY rats. Autoradiographic examination of brainstem sections preincubated with [125I]p-iodoclonidine revealed no inter-strain differences in alpha(2)-binding in control rats. Ethanol feeding caused strain-dependent changes in alpha(2)-binding activity, which comprised significant (P<0.05) decreases in the density of alpha(2)-binding sites in both areas of the NTS in SHRs versus no effect in WKY rats. These findings do not favor a role for brainstem alpha(2)-adrenoceptors in ethanol-induced attenuation of baroreflexes. Interestingly, the ethanol-evoked reduction in the NTS alpha(2)-receptor density in SHRs may explain reported findings that ethanol abolishes the hypotensive effect of the alpha(2)-adrenoceptor agonist clonidine in this rat model.

Animals↗
PubMed1976

Improved intracerebral chemitrode for chemical and electrical studies of the brain.

An intracerebral chemitrode is described for infusion and recovery of solutes as well as stimulation and recording of discrete brain loci. The chemitrode consists of two insulated tubes in juxtaposition with implantable angular ends faced together and covered with a high porosity polycarbonate Nuclepore membrane so as to create a sealed, nonclogging, perfusion chamber. Electrical connectors are affixed directly to the tubes at the external end for stimulating and recording of the perfusion area. Experiments showing electrical stimulation of the chemitrode to produce epileptic foci at the site of perfusion, infusion of drugs to produce changes in brain activity and extraction of ethanol following peripheral injection demonstrate the potential utility of the chemitrode in a wide variety of neurobiological problems.

Animals↗
PubMed2000

Constitutive biosynthesis and localization of alcohol oxidase in the ethanol-insensitive catabolite repression mutant ecr1 of the yeast Pichia methanolica.

The activity and localization of alcohol oxidase (EC 1.1.3.13) have been studied in the Pichia methanolica mutant ecr1 defective in ethanol-induced catabolite repression of enzymes of methanol utilization. Ultrasctuctural, immunocytochemical, and biochemical analyses revealed the presence of peroxisomes containing active alcohol oxidase in the mutant grown in media with methanol, ethanol, and a mixture of both substrates. No alcohol oxidase was detected in the wild-type cells (ECR1) grown on ethanol-containing media. Mutant ecr1 growing in medium containing a mixture of different alcohols and the wild-type strain growing on methanol demonstrated similar buoyant density of peroxisomes (1.24-1.27 g/cm3)during isopicnic centrifugation of the organelles in sucrose density gradients. The integrated genetic, immunocytochemical, and biochemical data are in agreement with the model that synthesis, translocation into peroxisomes, and assembly of alcohol oxidase in P. methanolica may not require any regulatory signals induced by methanol.

Alcohol Oxidoreductases↗
PubMed1985

Direct evidence for enhanced axon sprouting in adult rats exposed to ethanol in utero.

The anterograde transport of horseradish peroxidase (HRP) was utilized to examine the post-lesion expansion of the commissural projection to the molecular layer of the dentate gyrus in adult rats prenatally exposed to ethanol, and in normal and pair-fed controls. Mean daily ethanol consumption by the pregnant dams was 12.0 +/- 1.6 g/kg. Similar consumption in a separate group of pregnant dams produced mean blood ethanol concentrations of 102.8 +/- 5.2 mg/dl of blood. The commissural terminal field of rats exposed to ethanol in utero and given unilateral entorhinal lesions as adults exhibited a significantly greater expansion compared to controls. There were no differences in the HRP-labeled terminal fields between normal and pair-fed animals with similar lesions, suggesting that the effect in the ethanol-exposed rats was due to ethanol teratogenicity rather than reduced caloric intake. Furthermore, the effect was not a function of altered organization of commissural and perforant path terminal fields (terminal field overlap). These data demonstrate that exposure to ethanol in utero produces long-lasting alterations in lesion-induced axon sprouting.

Animals↗
PubMed2000

Clostridium scatologenes strain SL1 isolated as an acetogenic bacterium from acidic sediments.

A strictly anaerobic, H2-utilizing bacterium, strain SL1, was isolated from the sediment of an acidic coal mine pond. Cells of strain SL1 were sporulating, motile, long rods with a multilayer cell wall. Growth was observed at 5-35 degrees C and pH 3.9-7.0. Acetate was the sole end product of H2 utilization and was produced in stoichiometries indicative of an acetyl-CoA-pathway-dependent metabolism. Growth and substrate utilization also occurred with CO/CO2, vanillate, syringate, ferulate, ethanol, propanol, 1-butanol, glycerine, cellobiose, glucose, fructose, mannose, xylose, formate, lactate, pyruvate and gluconate. With most substrates, acetate was the main or sole product formed. Growth in the presence of H2/CO2 or CO/CO2 was difficult to maintain in laboratory cultures. Methoxyl, carboxyl and acrylate groups of various aromatic compounds were O-demethylated, decarboxylated and reduced, respectively. Small amounts of butyrate were produced during the fermentation of sugars. The acrylate group of ferulate was reduced. Nitrate, sulfate, thiosulfate, dimethylsulfoxide and Fe(III) were not utilized as electron acceptors. Analysis of the 16S rRNA gene sequence of strain SL1 demonstrated that it is closely related to Clostridium scatologenes (99.6% sequence similarity), an organism characterized as a fermentative anaerobe but not previously shown to be capable of acetogenic growth. Comparative experiments with C. scatologenes DSM 757T demonstrated that it utilized H2/CO2 (negligible growth), CO/CO2 (negligible growth), formate, ethanol and aromatic compounds according to stoichiometries indicative of the acetyl-CoA pathway. CO dehydrogenase, formate dehydrogenase and hydrogenase activities were present in both strain SL1 and C. scatologenes DSM 757T. These results indicate that (i) sediments of acidic coal mine ponds harbour acetogens and (ii) C. scatologenes is an acetogen that tends to lose its capacity to grow acetogenically under H2/CO2 or CO/CO2 after prolonged laboratory cultivation.

Acetates↗
PubMed1989

Increased plasma levels of glutathione and malondialdehyde after acute ethanol ingestion in humans.

The effect of acute ethanol consumption on plasma glutathione (GSH) and malondialdehyde (MDA) concentrations was studied in two groups of healthy male subjects. The first group (n = 15) received an acute dose of ethanol (1.5 g/kg p.o. over a period of 3 h); in the control group (n = 15), ethanol was replaced isocalorically with carbohydrates. Blood samples were taken at 0 time (ethanol/carbohydrates ingestion) and every 60 min for 6 h. A significant increase in plasma MDA concentration as well as in plasma GSH values were observed in subjects receiving ethanol compared to controls. The enhancement of plasma GSH was accompanied by a concomitant increase of oxidized glutathione (GSSG). These data support the hypothesis of an increase of lipid peroxidation as a possible mechanism of acute ethanol toxicity. The enhancement of plasma GSH and GSSG may reflect an increased utilization and loss of the tripeptide from the liver induced by ethanol.

Adult↗
PubMed1996

Ethanol acutely impairs glycogen repletion in skeletal muscle following high intensity short duration exercise in the rat.

Ethanol is recognized to affect adversely carbohydrate metabolism in skeletal muscle. This paper seeks to establish whether ethanol acutely impairs glycogen repletion during recovery from high intensity short duration exercise in the rat. High intensity exercise caused the massive mobilization of glycogen stores in muscles rich in type IIa and IIb fibres and marked increases in plasma and muscle lactate levels. During the 30-minute recovery period, there was substantial glycogen repletion in these muscles in both the ethanol-treated and control rats. Ethanol, however, was associated with reduced glycogen resynthesis in both the tibialis anterior (by 22%) and red gastrocnemius (by 31%) muscles but not in the white gastrocnemius muscle. This reduction in post-exercise glycogen deposition was accompanied by decreased lactate disposal and elevated plasma glucose levels. These effects of ethanol on glycogen repletion may involve interactions with hepatic gluconeogenesis, glucose uptake and utilization in muscle, muscle glycogen synthesis and lactate glyconeogenesis. The ethanol-mediated impairment in post-exercise glycogen repletion may have important implications for the pathogenesis of chronic alcoholic skeletal myopathy.

Journal Article↗
PubMed1999

Fermentability of the hemicellulose-derived sugars from steam-exploded softwood (douglas fir)

Steam explosion ofDouglas fir wood chips under low-severity conditions (log Ro = 3.08 corresponding to 175 degrees C, 7.5 min, and 4.5% SO2) resulted in the recovery of around 87% of the original hemicellulose component in the water-soluble stream. More than 80% of the recovered hemicellulose was in a monomeric form. As the pretreatment severity increased from 3.08 to 3.76, hemicellulose recovery dropped to 43% of the original hemicellulose found in Douglas fir chips while the concentration of glucose originating from cellulose hydrolysis increased along with the concentration of sugar degradation products such as furfural and hydroxymethylfurfural. Despite containing a higher concentration of hexose monomers (mainly glucose originating from cellulose degradation), the water-soluble fraction prepared under high-severity conditions (log Ro = 3.73 corresponding to 215 degrees C, 2.38 min, and 2.38% SO2) was not readily fermented. Only the two hydrolyzates obtained at low and medium (195 degrees C, 4.5 min, and 4.5% SO2) severities were fermented to ethanol using a spent sulfur liquor adapted strain of Saccharomyces cerevisiae. High ethanol yields were obtained for these two hydrolyzates with 0.44 g of ethanol produced per gram of hexose utilized (86% of theoretical). However, the best results of hemicellulose recovery and fermentability were obtained for the low-severity water-soluble fraction which was fermented significantly faster than the fraction obtained after medium-severity treatment probably because it contained higher amounts of fermentation inhibitors. Copyright 1999 John Wiley & Sons, Inc.

Journal Article↗
PubMed2003

Enzymatic hydrolysis of water-soluble wheat arabinoxylan. 1. Synergy between alpha-L-arabinofuranosidases, endo-1,4-beta-xylanases, and beta-xylosidase activities.

Hydrolysis of arabinoxylan is an important prerequisite for improved utilization of wheat hemicellulose in the ethanol fermentation industry. This study investigates the individual and combined efficiencies of three commercial, cellulytic and hemicellulytic enzyme preparations, Celluclast 1.5 L, Ultraflo L, and Viscozyme L, in catalyzing the liberation of arabinose and xylose from water-soluble wheat arabinoxylan. Ultraflo L was the best enzyme preparation for releasing arabinose, liberating 53 wt% of the theoretical maximum after 48 h of reaction (10 wt% enzyme/substrate ratio, 40 degrees C, pH 6). Celluclast 1.5 L was superior to the other enzyme preparations in releasing xylose, liberating 26 wt% of the theoretical maximum after 48 h of reaction (10 wt% enzyme/substrate ratio, 50 degrees C, pH 5). The 50:50 mixtures of the enzyme preparations showed no synergistic cooperation in arabinose release, but a synergistic interaction in xylose release was found between Ultraflo L and Celluclast 1.5 L. On the basis of high-performance anion exchange chromatography (HPAEC) analysis of the hydrolysates after enzymatic reaction, we propose that the observed synergism between Celluclast 1.5 L and Ultraflo L is the result of positive interaction between alpha-L-arabinofuranosidase and endo-1,4-beta-xylanase activities present in Ultraflo L that released arabinose, xylobiose and xylotriose, and beta-xylosidase activities in Celluclast 1.5 L, capable of catalyzing the hydrolysis of xylobiose and xylotriose to xylose.

Arabinose↗
PubMed2003

Effect of specific oxygen uptake rate on Enterobacter aerogenes energetics: carbon and reduction degree balances in batch cultivations.

The effect of oxygen availability on the metabolism of Enterobacter aerogenes NCIMB 10102 was studied through batch fermentations of glucose performed increasing the specific oxygen uptake rate up to 72.7 mmol(O2) C-mol(DW) (-1) x h(-1). The final concentrations of fermentation products of this biosystem (2,3-butanediol, hydrogen, acetoin, formate, acetate, carbon dioxide, ethanol, lactate, succinate, and biomass) were utilized to check the use of simple carbon mass and reduction degree balances for the study of microbial energetics even in batch cultivations.

Adenosine Triphosphate↗
PubMed1984

The iron-hydrogen peroxide-iodide system is fungicidal: activity against the yeast phase of Blastomyces dermatitidis.

A series of experiments show the potency of a newly described microbicidal system, involving iron, H2O2, and halide, in killing a fungus (Blastomyces dermatitidis). B dermatitidis has previously been shown susceptible to the myeloperoxidase-H2O2-halide system. The present studies show killing of either of two strains in 1 hour if Fe++ at 5 X 10(-5)M, H2O2 at 5 X 10(-5)M and Kl at 5 X 10(-4)M are all present (P less than 0.001). EDTA, a Fe++ chelator, abrogates killing. The mechanism presumably utilizes hydroxyl radical, since an inhibitor, ethanol, also neutralizes the system. The bactericidal and fungicidal system is of great potential importance in vivo.

Antifungal Agents↗
PubMed2002

High-level ethanol production from starch by a flocculent Saccharomyces cerevisiae strain displaying cell-surface glucoamylase.

A Strain of host yeast YF207, which is a tryptophan auxotroph and shows strong flocculation ability, was obtained from SaccharomYces diastaticus ATCC60712 and S. cerevisiae W303-1B by tetrad analysis. The plasmid pGA11, which is a multicopy plasmid for cell-surface expression of the Rhyzopus oryzae glucoamylase/alpha-agglutinin fusion protein, was then introduced into this flocculent yeast strain (YF207/pGA11). Yeast YF207/pGA11 grew rapidly under aerobic condition (dissolved oxygen 2.0 ppm), using soluble starch. The harvested cells were used for batch fermentation of soluble starch to ethanol under anaerobic condition and showed high ethanol production rates (0.71 g h(-1) l(-1)) without a time lag, because glucoamylase was immobilized on the yeast cell surface. During repeated utilization of cells for fermentation, YF207/pGA11 maintained high ethanol production rates over 300 h. Moreover, in fed-batch fermentation with YF207/pGA11 for approximately 120 h, the ethanol concentration reached up to 50 g l(-1). In conclusion, flocculent yeast cells displaying cell-surface glucoamylase are considered to be very effective for the direct fermentation of soluble starch to ethanol.

Aerobiosis↗
PubMedDate not supplied

Alcohol-nutrition interaction: 1984 update.

Alcohol remains a prevailing cause of malnutrition resulting in a variety of deficiency states secondary to decreased intake of nutrients. In addition to various well described primary malnutrition syndromes, secondary malnutrition may result from the interaction of ethanol with nutrient digestion, absorption or utilization. Some of the latter alcohol-nutrient interactions have been recently defined and their pathogenesis is discussed in this review. Included are interactions with thiamine, folic acid, vitamin A and disorders secondary to amino acid imbalances. The rationale for various forms of therapy is reviewed, including the treatment aimed at correcting the "hypermetabolic state" in alcoholics ad the pitfalls of excess nutrient administration (particularly as it pertains to pyridoxine, vitamin A and amino acids). The desirability of recognizing early precirrhotic stages of alcoholic fibrosis is emphasized, in order to start therapy prior to the medical and/or social disintegration of the alcoholic.

Alcoholism↗
PubMed1990

The production of reactive oxygen species by dietary flavonols.

Flavonols are a group of naturally occurring compounds which are widely distributed in nature where they are found glycosylated primarily in vegetables and fruits. A number of studies have found both anti- and prooxidant effects for many of these compounds. The most widely studied because of their ubiquitous nature have been quercetin, a B-dihydroxylated and myricetin, a B-trihydroxylated flavonol. Some of their prooxidant properties have been attributed to the fact that they can undergo autooxidation when dissolved in aqueous buffer. Studying a number of factors affecting autooxidation, we found the rate of autooxidation for both quercetin and myricetin to be highly pH dependent with no autooxidation detected for quercetin at physiologic pH. Both the addition of iron for the two flavonols and the addition of iron followed by SOD for quercetin at physiologic pH. Both the addistantially. Neither kaempferol, a monohydroxylated flavonol nor rutin, a glycosylated quercetin showed any ability to autooxidize. The results with rutin differ from what we expected based on the B-ring structural similarity to quercetin. The autooxidation of quercetin and myricetin was further studied by electron spin resonance spectroscopy (ESR). Whereas quercetin produced a characteristic DMPO-OH radical, it was not detected below a pH of 9. However, the addition of iron allowed the signal to be detected at a pH as low as 8.0. On the other hand, myricetin autooxidation yielded a semiquinone signal which upon the addition of iron, converted to a DMPO-OH signal detected at a pH of 7.5. In a microsome-NADPH system, quercetin produced an increase in oxygen utilization and with ESR, an ethanol-derived radical signal which could be completely suppressed by catalase indicating the dependence of the signal on hydrogen peroxide. These studies demonstrate that the extracellular production of active oxygen species by dietary flavonols is not likely to occur in vivo but the potential for intracellular redox cycling may have toxicologic significance.

Animals↗