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PubMed1994

Iron supply of Pasteurella multocida and Pasteurella haemolytica.

Pasteurella multocida and Pasteurella haemolytica do not produce hydroxamate- or phenolate type siderophores. However, transport- and utilization systems could be detected for the well known siderophores ferrioxamine B, E, G, rhizoferrin and the intermediate 2,3-dihydroxybenzoic acid by means of cross-feeding tests in both Pasteurella species. Enterobactin and ferrichrome did not feed any of the Pasteurella strains tested. Additionally, alpha-ketoacids and alpha-hydroxyacids such as pyruvic acid, alpha-hydroxyisovaleric acid and others acting as primary metabolites enabled growth of P. multocida and P. haemolytica under iron limitation.

Culture Media↗
PubMedDate not supplied

Inhibition by analogues of L-tyrosine transport by B16/F10 melanoma cells.

The effect of a number of L-tyrosine (L-Tyr) analogues on L-Tyr uptake by B16/F10 malignant melanocytes is reported. This amino acid can be taken up by two of the most ubiquitous transport systems found in animals cells, L and presumably ASC. L-Tyr analogues devoid of the amino group, like p-hydroxyphenyl pyruvic acid and related compounds, and L-Tyr analogues devoid of the carboxyl group, such as tyramine, do not affect L-Tyr uptake. The other aromatic amino acids, L-Phe and L-Trp, and the L-Tyr analogues DL-m-Tyr, L-diiodotyrosine and L-dopa, strongly inhibit the uptake of L-Tyr. This suggests that these chemicals are transported more efficiently than L-Tyr. The ASC system does not show stereospecificity, but the L system has greater affinity for L-Tyr than for D-Tyr. The ASC system also has greater affinity for tyrosine isomers with the hydroxyl group in the ortho and meta positions. The presence of a methyl group at the alpha-carbon of L-Tyr and L-dopa also increases the affinity of the ASC system for these agents. In contrast, alpha-methylation decreases the affinity of the L system in comparison to L-Tyr. Finally, L-Tyr esters do not inhibit, but stimulate the transport of L-Tyr, mainly by the ASC system.

Amino Acid Transport Systems↗
PubMed1985

An autoperfused heart-lung-preparation: metabolism and function.

The number of heart transplantations performed in the United States is increasing, and better preservation techniques are needed for distant transport and improved organ viability. Earlier experiments demonstrated that the autoperfused heart-lung preparation maintains adequate function for six to seven hours without exogenous substrates or medications. The present study evaluated the metabolic alterations at normothermia in an autoperfused heart-lung preparation and if its longevity can be extended by satisfying metabolic requirements. Thirty autoperfused heart-lung preservations were tested with an elevated buffer-bag that maintained left ventricle pressure between 75 mm Hg and 80 mm Hg. The entry and exit ports of the buffer-bag were fitted with one-way valves to insure blood circulation. Left ventricle and arterial pressure, blood pH, PCO2, PO2, glucose, free fatty acids, pyruvate and lactate were measured at regular intervals. In a first series of experiments, myocardial biopsies were taken for ATP determinations. The autoperfused heart-lung preparations were found to consume preferentially free fatty acids until their arterial level dropped to 350 +/- 24 microEq/L. Glucose then became the perferred substrate. After six to seven hours, when the glucose level dropped to 10 mg/dL, the cardiac activity stopped. In a second series, a 10% glucose solution containing 25 IU/dL of insulin was infused at a rate of 0.1 mL/min, extending the longevity of the preparation up to 18 hours. Then, the heart dilated and abruptly stopped. Massive bacterial contamination was found. When aseptic techniques were used in conjunction with antibiotics, the longevity was extended to 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Changes in liver enzyme activity in alloxan diabetes rats].

Activities of pyruvate kinase, lactate and malate dehydrogenases as well as concentration of oxaloacetate, lactic and pyruvic acids and of glycerol-I-phosphate were altered in liver tissues of rats with alloxane diabetes. Alteration in activity of LDH and MDH isoenzymes appears to be responsible for regulation of the content of pyrimidine nucleotides oxidized and reduced forms, which limit the glucose oxidation.

Animals↗
PubMed1993

Glucose uptake and end product formation in an intertidal marine sediment.

Glucose uptake was monitored on a seasonal basis, using [6-H]glucose and undisturbed cores collected from an intertidal mud flat. The fate of glucose carbon, including the formation of CO(2) and biomass, was assayed by using undisturbed cores and [U-C]glucose; the production of short-chain fatty acids was monitored with [U-C]glucose and sediment slurries. Rate constants for glucose uptake varied temporally, with temperature accounting for much of the variability; turnover times ranged from about 2 to 10 min. Rate constants decreased with increasing sediment depth and in the following order for several common monosaccharides: glucose>galactose>mannose approximately fucose. Time course analyses of CO(2) production provided evidence of significant isotopic dilution; although pore water glucose turnover times were on the order of minutes, CO(2) did not plateau until after approximately 6 h of incubation. At this time a maximum of about 40% of the added radioglucose had been respired. The extent of respiration varied as a function of sediment depth and season, with the highest values below the surface (4 to 7 cm) and in summer and fall. Incorporation of radiolabelled glucose into biomass also varied seasonally, but the greatest extent of incorporation (about 40%) was observed in the fall and for the 0- to 1-cm depth interval. The production of short-chain fatty acid end products was largely limited to acetate, which accounted for only a small percentage of the added radiolabel. Other organic acids, pyruvate in particular, were observed in pore water and were due to artifacts in the heat-kill procedure used to terminate incubations. An accurate assessment of the distribution and importance of short-chain fatty acids as end products required the use of an enzymatic technique coupled with high-pressure liquid chromatography to verify qualitative identities.

Journal Article↗
PubMed1997

Sequences and expression of pyruvate dehydrogenase genes from Pseudomonas aeruginosa.

A mutant of Pseudomonas aeruginosa, OT2100, which appeared to be defective in the production of the fluorescent yellow-green siderophore pyoverdine had been isolated previously following transposon mutagenesis (T. R. Merriman and I. L. Lamont, Gene 126:17-23, 1993). DNA from either side of the transposon insertion site was cloned, and the sequence was determined. The mutated gene had strong identity with the dihydrolipoamide acetyltransferase (E2) components of pyruvate dehydrogenase (PDH) from other bacterial species. Enzyme assays revealed that the mutant was defective in the E2 subunit of PDH, preventing assembly of a functional complex. PDH activity in OT2100 cell extracts was restored when extract from an E1 mutant was added. On the basis of this evidence, OT2100 was identified as an aceB or E2 mutant. A second gene, aceA, which is likely to encode the E1 component of PDH, was identified upstream from aceB. Transcriptional analysis revealed that aceA and aceB are expressed as a 5-kb polycistronic transcript from a promoter upstream of aceA. An intergenic region of 146 bp was located between aceA and aceB, and a 2-kb aceB transcript that originated from a promoter in the intergenic region was identified. DNA fragments upstream of aceA and aceB were shown to have promoter activities in P. aeruginosa, although only the aceA promoter was active in Escherichia coli. It is likely that the apparent pyoverdine-deficient phenotype of mutant OT2100 is a consequence of acidification of the growth medium due to accumulation of pyruvic acid in the absence of functional PDH.

Amino Acid Sequence↗
PubMedDate not supplied

[Mechanism of the action of apressin under conditions of high temperature and physical exertion].

In experiments on rats subject to study were regularities governing the metabolism of glycogen, milk, pyruvic acid, phosphocreatine in the liver tissues, cortex, musculus gastrocnemius and in the myocardium, as well as of acids in the peripheral blood at 40 degrees C of outside temperature, 95 per cent humidity and during swimming. Investigations also covered preventive application of apressin in rats. The influence of stress was found to produce metabolic changes in the organism of rats. In hypoxia apressin tended to prolong the life-span of the test animals by as much as 30 per cent, to keep intact metabolism in the musculus gastrocnemius and in the myocardium, but, when used in a dose of 0.05 mg/kg, it failed to avert disorders in the cortex tissues.

Adrenergic alpha-Antagonists↗
PubMed1984

Purification and characterization of C-S lyase from Fusobacterium varium. A C-S cleavage enzyme of cysteine conjugates and some S-containing amino acids.

An enzyme responsible for the carbon-sulfur bond cleavage of various S-aryl, S-aralkyl, and S-alkyl cysteines has been purified about 270-fold from Fusobacterium varium. Incubation of a cysteine conjugate of p-bromobenzene with the enzyme yielded equimolar amounts of p-bromobenzenethiol, pyruvic acid, and ammonia, indicating that the carbon-sulfur bond cleavage proceeds via an alpha, beta-elimination reaction. The enzyme activity was inhibited either by hydroxylamine or KCN and stabilized by pyridoxal phosphate, which probably acted as cofactor. The broad substrate spectrum of this enzyme suggested an important role of the intestinal microflora in the in vivo formation of methylthio-containing metabolites of various xenobiotics.

Chromatography, DEAE-Cellulose↗
PubMed1989

Biochemistry of the various fractions of sarcocysts of Sarcocystis fusiformis of buffalo (Bubalus bubalis).

A comparative biochemical study on the various fractions (cyst wall, cyst fluid and zoites) of the sarcocysts of Sarcocystis fusiformis from oesophageal muscles of naturally infected Indian water buffalo (Bubalus bubalis) was carried out. The study included analysis for glycogen, glucose, pyruvic acid, lactic acid, total lipids, phospholipids, cholesterol, triglycerides and fatty acids. The pattern and the distribution of various biochemical constituents varied in the different fractions. The cell wall had the maximum concentration of glucose and phospholipids. Of all the fractions, cell fluid showed the highest contents of pyruvate and lactate, but with a higher level of pyruvate than lactate.

Animals↗
PubMed1999

Oxaloacetate decarboxylase from Pseudomonas stutzeri: purification and characterization.

Oxaloacetate decarboxylase (OXAD), the enzyme that catalyzes the decarboxylation of oxaloacetate to pyruvic acid and carbon dioxide, was purified 245-fold to homogeneity from Pseudomonas stutzeri. The three-step purification procedure comprised anion-exchange chromatography, metal-chelate affinity chromatography, and biomimetic-dye affinity chromatography. Estimates of molecular mass from sodium dodecyl sulfate-polyacrylamide gel electrophoresis and native high-performance gel-filtration liquid chromatography were, respectively, 63 and 64 kDa, suggesting a monomeric protein. OXAD required for maximum activity divalent metal cations such as Mn2+ and Mg2+ but not monovalent cations. The enzyme is not inhibited by avidin, but is competitively inhibited by adenosine 5'-diphosphate, acetic acid, phosphoenolpyruvate, malic acid, and oxalic acid. Initial velocity, product inhibition, and dead-end inhibition studies suggested a rapid-equilibrium ordered kinetic mechanism with Mn2+ being added to the enzyme first followed by oxaloacetate, and carbon dioxide is released first followed by pyruvate. Inhibition data as well as pH-dependence profiles and kinetic parameters are reported and discussed in terms of the mechanism operating for oxaloacetate decarboxylation.

Bicarbonates↗
PubMed1965

Free Amino Acids in Serine-Antagonized Cells of Tetrahymena pyriformis.

Wragg, June B. (Agricultural Research Service, Beltsville, Md.), Howard Reynolds, and Michael J. Pelczar, Jr. Free amino acids in serine-antagonized cells of Tetrahymena pyriformis. J. Bacteriol. 90:748-754. 1965.-Growth inhibition of Tetrahymena pyriformis by l-serine in a chemically defined medium was reversed by l-arginine in a manner which resembled competitive antagonism. Composition of the free amino acid pools from cells grown in either a balanced amino acid mixture or a mixture with serine concentrations which inhibited growth suggested an antagonism by serine with energy-yielding reactions. Growth in media with excess serine resulted in the accumulation of higher concentrations of free cellular amino acids and an apparent increase in the rate of conversion of arginine to ornithine, as compared with growth in the balanced medium. The results suggested that serine or a metabolic product of serine interferes with the formation of pyruvic acid. In the presence of high levels of serine, arginine appeared to be metabolized more rapidly and to be spared when alanine, aspartic acid, or glutamic acid was added to the unbalanced medium.

Journal Article↗
PubMed1977

[Clinico-experimental evaluation of therapeutic effectiveness of 1-dihydroxyphenylalanine in circulatory insufficiency].

The indices of central hemodynamics and myocardial contractility were studied by poly- and mechanocardiography in 25 patients with stage I-IIA circulatory insufficiency prior to and after treatment with 1-dioxyphenlalanine. The content of lactic and pyruvic acids in the blood and erythrocyte permeability to 32P were determined at the same time. The activity of the redox enzymes was studied in rats with experimentally induced circulatory insufficiency on the background of 1-DOPA medication. It was established that contractility of the heart and indices of central hemodynamics improved due to the effect of 1-DOPA. A decrease in the lactate concentration and an elevation of the pyruvate level in the blood of patients were noted. In animal experiments increased activity of cytochrome oxidase, succinic dehydrogenase, and alkaline and acid phosphatase in the myocardium was demonstrated.

Animals↗
PubMed1988

Structural studies of the Escherichia coli O-149 O-antigen polysaccharide.

The structure of the O-antigen polysaccharide from Escherichia coli O-149 has been investigated; methylation analysis, partial hydrolysis with acid, and n.m.r. spectroscopy were the principal methods used. It is concluded that the polysaccharide is composed of trisaccharide repeating-units having the following structure. (Formula: see text). The absolute configuration at the acetalic carbon atom of the pyruvic acid residue is S.

Antigens, Bacterial↗
PubMed1984

Transamination of 3-phenylpyruvate in pancreatic B-cell mitochondria.

High aminotransferase activities catalyzing the reaction between L-glutamate and the aromatic ketomonocarboxylic acid, 3-phenylpyruvate, were observed in the mitochondria from pancreatic B-cells. At very low concentrations of 3-phenylpyruvate, L-glutamine was an effective amino group donor. The aminotransferase activities for the aliphatic ketomonocarboxylic acids, pyruvate and 2-ketoisovalerate, were lower in B-cell mitochondria. High rates of transamination of 2-ketoisocaproate with L-glutamine were observed and may be an important prerequisite for the insulin secretory potency of this 2-keto acid. Since B-cell mitochondria are well supplied with L-glutamine and L-glutamate, 3-phenylpyruvate-induced 2-ketoglutarate production may explain the insulin secretory potency of 3-phenylpyruvate which is not a fuel for pancreatic islet cells.

Animals↗
PubMed1975

[Certain characteristics of myocardial metabolism in long-term experimental hypotension and the effect of administration of adenosine triphosphate and fructose 1,6-diphosphate].

Several indices of energy exchange and protein-amino acid metabolism in the myocardium were studied experimentally in dogs subjected to long-term hypotension (Wiggers' technique, arterial pressure of 40 mm Hg for 3 hours). It was established that by the end of the fixed period of hypotension the myocardial content of adenosine triphosphate, creatinephosphate, glycogen decreased significantly, while the amount of nonorganic phosphorus, lactic and pyruvic acids increased. At the same time the content of watersoluble protein fraction and of most of the 18 identified amino asids decreases in the cardiac muscle. Fractionated intravenous injections of adenosine triphosphate or 1,6-diphosphate fructose permitted to prevent the development of energy deficit, and, to a great extent, that of protein-amino acid metabolism disorders in dogs subjected to long-term hypotension.

Adenosine Triphosphate↗