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PubMed1969

Structural analysis of colanic acid from Escherichia coli by using methylation and base-catalysed fragmentation. Comparison with polysaccharides from other bacterial sources.

Essentially the same methanolysis products were obtained after methylation of the slime and capsular polysaccharides from Escherichia coli K12 (S53 and S53C sub-strains) and the slime polysaccharides from E. coli K12 (S61), Aerobacter cloacae N.C.T.C. 5290 and Salmonella typhimurium SL1543. These were the methyl glycosides of 2-O-methyl-l-fucose, 2,3-di-O-methyl-l-fucose, 2,3-di-O-methyl-d-glucuronic acid methyl ester, 2,4,6-tri-O-methyl-d-glucose, 2,4,6-tri-O-methyl-d-galactose and the pyruvic acid ketal, 4,6-O-(1'-methoxycarbonylethylidene)-2,3-O-methyl-d-galactose. All were identified as crystalline derivatives from an E. coli polysaccharide. The structure of the ketal was proved by proton-magnetic-resonance and mass spectrometry, and by cleavage to pyruvic acid and 2,3-di-O-methyl-d-galactose. All these polysaccharides are therefore regarded as variants on the same fundamental structure for which the name colanic acid is adopted. Although containing the same sugar residues, quite different methanolysis products were obtained after methylation of the extracellular polysaccharide from Klebsiella aerogenes (1.2 strain). The hydroxypropyl ester of E. coli polysaccharide, when treated with base under anhydrous conditions, underwent beta-elimination at the uronate residues with release of a 4,6-O-(1'-alkoxycarbonylethylidene)-d-galactose. Together with the identification of 3-O-(d-glucopyranosyluronic acid)-d-galactose as a partial hydrolysis product, this establishes the nature of most, if not all, of the side chains as O-[4,6-O-(1'-carboxyethylidene)-d-galactopyranosyl]-(1-->4)-O-(d-glucopyranosyluronic acid)-(1-->3)-d-galactopyranosyl...

Chemical Phenomena↗
PubMed1991

Structure of the major exopolysaccharide produced by Azotobacter beijerinckii B-1615.

A. beijerinckii strain B-1615 produced two acidic exopolysaccharides in the ratio approximately 9:1. The minor polysaccharide contained mannuronic and guluronic acids in the ratio 2.3:1 and is a bacterial alginate. The major polysaccharide consisted of D-galactose, L-rhamnose, and pyruvic acid in the ratios 2:1:1 and was acetylated. On the basis of methylation analysis, and 1H- and 13C-n.m.r. spectroscopy of the polysaccharide before and after removal of the pyruvic acid residues and O-deacetylation, it was concluded that the major polysaccharide had the structure [formula; see text] with up to 1.5 OAc groups per repeating unit.

Azotobacter↗
PubMedDate not supplied

Metabolism of hydralazine by rat hepatocytes.

The metabolism of hydralazine and its pyruvic acid hydrazone was studied in a medium containing isolated adult rat hepatocytes. Hydralazine undergoes conversion to 3-methyltriazolophthalazine, while hydralazine pyruvic acid hydrazone is not metabolized in rat hepatocytes.

Animals↗
PubMed1990

Short-chain fatty acid and organic acid concentrations in feces of healthy human volunteers and their correlations with anaerobe cultural counts during systemic ceftriaxone administration.

Short-chain fatty acid (SCFA) and organic acid concentrations and (an)aerobe cultural counts were determined simultaneously in fresh feces from 10 human volunteers before, during, and after 5 days of single-dose ceftriaxone administration. The changes and the correlation coefficients between these variables were tested to be significant (P less than 0.05). to investigate whether significant changes in the intestinal microflora could be predicted by significant changes in SCFA/organic acid concentrations. Multivariate analysis was used with the same objective. Significant decreases in most SCFA, total SCFA (0.01 less than P less than 0.02), and pyruvic acid (0.02 less than P less than 0.05) concentrations in feces were found on day 3 of treatment and also on day 5, with the exception of the pyruvic acid concentrations. Lactic acid concentrations, however, were significantly increased (0.01 less than P less than 0.02) on day 5. All anaerobic cultural counts were significantly decreased (P less than 0.05) on days 3 and 5 of treatment except those for Clostridium difficile agar, which were only decreased on day 5. Highly significant correlations were found on day 3 between the total anaerobe counts (P less than 0.001), the Bacteroides counts (P less than 0.001), and propionic acid, of which the latter had a predictive value during treatment. The results of multivariate analysis were significant but did not have a predictive value. From this study we can conclude that propionic acid concentrations during ceftriaxone treatment in healthy volunteers have a predictive value for the Bacteroides cultural counts. The results of this study must be confirmed by those from patients treated with ceftriaxone.

Adult↗
PubMed1976

[Discriminative analysis in detecting cardiac insufficiency in myocardial infarct on the basis of the values of stroke volume and blood lactic acid level].

In 203 patients with large focal and transmural myocardial infarctions the cardiac output was studied by means of the dye dilution method, as well as the content of the lactic (Barker and Summerson's technique) and pyruvic acids (Travina's technique). Along with the growth of cardiac insufficiency a fall was observed in the cardiac and stroke indices, and a growing content of the lactic and pyruvic acids and of the L/P factor. The stroke index and the blood lactate level proved to be the most informative values. With a stroke index below 24 ml/m2 all patients with myocardial infarction displayed signs of cardiac insufficiency, while with a stroke index above 54.2 ml/m2 cardiac insufficiency was lacking. A stroke index falling between 24 and 54.2 ml/m2 was observed in both the patients with cardiac insufficiency, and in those without it. A lactic acid content above 31.8 mg% was always concomitant with cardiac insufficiency. With the lactic acid level ranging from 16 to 31.8 mg% the probability of cardiac insufficiency was doubtful.

Acute Disease↗
PubMed1996

The excessive production of indole-3-acetic acid and its significance in studies of the biosynthesis of this regulator of plant growth and development.

Because of the importance of indole-3-acetic acid (IAA) in the growth and development of plants, extensive studies of the biosynthesis of IAA have been performed during the four decades since the discovery of IAA as a plant hormone. The pathway for the biosynthesis of IAA in plants remains, however, to be unelucidated, even though studies within the past decade have revealed unexpected aspects of such biosynthesis. By contrast, two pathways to IAA have been characterized in bacteria at the molecular level: the indole-3-acetamide (IAM) pathway (L-tryptophan-->IAM-->IAA); the indole-3-pyruvic acid pathway (L-tryptophan-->indole-3-pyruvic acid-->indole-3-acetaldehyde-->IAA) (Fig. 1). In both pathways, the details of the biosynthesis of IAA were clarified using IAA-overproducing bacteria. After a description of recent advances of the studies of the biosynthesis of IAA in plants, this review focuses on the excessive production of IAA in several organisms and its significance in the studies of the biosynthesis of IAA.

Forecasting↗
PubMedDate not supplied

[Carbohydrate metabolism during poisoning with the cholinesterase inhibitor O-ethyl-S-hexylmethylthiophosphonate].

It is established that a decrease in glycogen content in liver begins at the early stages of intoxication with LG-63 and progresses with development of intoxication phenomena. Sugar content in liver and blood augments in parallel with decreasing content of glycogen in liver; concentration of ketone bodies and content of bisulfite-binding substances and pyruvic acid in liver also increase. In skeletal muscles, glycogen content was practically without changes; content of sugar, bisulfite-binding substances and pyruvic acid decreased while level of ketone bodies increased. In brain, utilization of ketone bodies decreased and in myocardium, increased.

Animals↗
PubMed2005

Ethyl pyruvate protects PC12 cells from dopamine-induced apoptosis.

Pyruvate acid can protect cells against oxidative damage. However, its instability limits its usefulness as a therapeutic agent. In this study, we examined the effect of ethyl pyruvate, an aliphatic ester derived from pyruvate acid, on dopamine-induced cytotoxicity in rat pheochromocytoma PC12 cells. The results demonstrated that dopamine induced apoptosis in PC12 cells accompanied with increases of intercellular reactive oxygen species, nuclear translocation of nuclear transcription factor kappa B (NF-kappaB) and expression of p53 and decrease of mitochondrial transmembrane potential. Ethyl pyruvate markedly reduced the dopamine-induced production of reactive oxygen species, nuclear translocation of NF-kappaB, upregulation of p53, loss of mitochondrial transmembrane potential and apoptosis in PC12 cells. The results suggested that ethyl pyruvate might protect PC12 cells against dopamine by suppressing intercellular oxidative stress and modulating key signal pathways of apoptosis, and that ethyl pyruvate might be used as a potential therapeutic agent for Parkinson's disease.

Acetylcysteine↗
PubMed1975

Anticonvulsant activity of N,N'-bis[3-(3-substituted urea)propyl]piperazines.

Several N,N'-bis[3-(3-substituted urea)propyl]piperazines were synthesized and characterized by their sharp melting points, elemental analyses, and IR spectra. All substituted piperazines were found to possess anticonvulsant activity, which was reflected by 20-70% protection observed against pentylenetetrazol-induced seizures in mice. Some of these compounds inhibited oxidation of pyruvic acid by rat brain homogenate. No correlation could be observed between the anticonvulsant activity possessed by these substituted piperazines and their ability to inhibit the oxidation of pyruvic acid.

Animals↗
PubMed1985

Effect of denervation on the glycolytic metabolism of the main electric organ of Electrophorus electricus (L.).

Biochemical modifications of the glycolytic metabolism of the electric organ of Electrophorus electricus (L.) have been studied as a function of denervation. The activities of LDH, MDH and the concentrations of ATP, lactic and pyruvic acids were measured at intervals of zero, 15, 30 and 60 days following denervation. In parallel, CPK activity was also measured. All of these biochemical characteristics were substantially altered by denervation. The results obtained point to a change, after 15 days of denervation, from the normal anaerobic to an aerobic metabolism which remains after 30 days and reverts to anaerobic at 60 days.

Adenosine Triphosphate↗
PubMed1980

Structure of the capsular polysaccharide of Klebsiella serotype K74.

The capsular polysaccharide of Klebsiella serotype K74 belongs to a chemogroup consisting of seven strains, of which four contain 1-carboxyethylidene groups (pyruvic acid acetals). The polysaccharide from K74 is demonstrated to be of the "3 + 2" type, and to be based on the repeating unit shown (Formula, see text). The capsular polysaccharide from Klebsiella K74 is composed of D-glucuronic acid, D-galactose, and D-mannose, and this chemotype includes a total of seven strains, of which four have 1-carboxyethylidene groups (pyruvic acid acetals). In this chemogroup, the structures of the capsular polysaccharides of the serotypes K20 (ref. 3) and K21 (ref. 4) have been published.

Carbohydrate Conformation↗
PubMedDate not supplied

[Microhemodynamics and energy metabolism in schizophrenia patients].

An apparent disturbance was revealed in microhaemodynamics of patients diagnosed as having schizophrenia (n = 210) which was more pronounced in continuously progredient form of the above medical condition. An increase in conjunctival indexes, polymorphic character of capillaries, decrease in numbers of capillary loops were revealed by biomicroscopy of the bulbar conjunctiva and capillaroscopy respectively. The patients showed lowering of ATP level and rise in the content of cathodic LDG4-LDG5 fractions, accumulation in blood of lactic and pyruvic acids.

Adenine Nucleotides↗
PubMed1984

Brewers' yeast pyruvate decarboxylase produces acetoin from acetaldehyde: a novel tool to study the mechanism of steps subsequent to carbon dioxide loss.

A gas-liquid chromatographic technique was developed for the determination of both acetaldehyde and the 3-4% acetoin side product that results from the brewers' yeast pyruvate decarboxylase (EC 4.1.1.1) catalyzed reaction of pyruvic acid. Employing this method enabled the demonstration of the catalysis of acetaldehyde condensation to acetoin by the enzyme. It was found that the acetoin produced enzymatically from pyruvic acid or from acetaldehyde was optically active, thus providing stereochemical information about the reaction. Deuterium kinetic isotope effects (employing CH3CHO and CH3CDO) were determined on the steady-state kinetic parameters to be 4.5 (Vmax) and 3.2 (Vmax/Kappm), respectively. This enabled, for the first time, the estimation of relative kinetic barriers for steps past decarboxylation. It could be concluded that (a) C-H bond scission was part of rate limitation in the enzyme-catalyzed condensation of acetaldehyde to acetoin and that (b) among the steps leading to the release of acetaldehyde, protonation of the key enamine intermediate was part of rate limitation. This latter finding is also directly applicable to the mechanism of pyruvate decarboxylation.

Acetaldehyde↗