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PubMed1987

Biosynthesis and stereochemical configuration of N5-(1-carboxyethyl)ornithine. An unusual amino acid produced by Streptococcus lactis.

In a recent communication (Thompson, J., Curtis, M. A., and Miller, S.P.F. (1986) J. Bacteriol. 167, 522-529) we described the purification and characterization of N5-(1-carboxyethyl)ornithine from cells of Streptococcus lactis 133. This unusual amino acid has not previously been found in nature. Radiotracer experiments presented here reveal that exogenous [14C]ornithine serves as the precursor for biosynthesis of [14C]arginine, [14C]N5-(1-carboxyethyl)ornithine, and [14C]N5-acetylornithine by cells of S. lactis K1 during growth in a defined medium lacking arginine. In the absence of both arginine and ornithine, cells of S. lactis K1 can also generate intracellular [14C]N5-(1-carboxyethyl)ornithine from exogenous [14C]glutamic acid. Previously we showed that the properties of N5-(1-carboxyethyl)ornithine prepared from S. lactis were identical to one of the two diastereomers [2S, 7S) or (2S, 7R] present in a synthetic preparation of (2S, 7RS)-N5-(1-carboxyethyl)ornithine. The two diastereomers have now been unambiguously synthesized by an Abderhalden-Haase condensation between (2S)-N2-t-butoxycarbonyl-ornithine and the chiral (2S)-, and (2R)-bromopropionates. By 13C-NMR spectroscopy it has been established that the preparation from S. lactis is exclusively (2S, 7S)-N5-(1-carboxyethyl)ornithine. has been demonstrated in a cell-free extract of S. lactis 133. The requirements for ornithine, pyruvic acid, and NAD(P)H suggest that biosynthesis of N5-(1-carboxyethyl)ornithine occurs via a reductive condensation mechanism. A general survey revealed that N5-(1-carboxyethyl)ornithine was produced only by certain strains of Group N streptococci. These findings may indicate a plasmid locus for the gene(s) encoding the enzyme(s) for N5-(1-carboxyethyl)ornithine biosynthesis.

Carbon Radioisotopes↗
PubMed2003

Indole derivatives produced by the fungus Colletotrichum acutatum causing lime anthracnose and postbloom fruit drop of citrus.

Postbloom fruit drop (PFD) of citrus and Key lime anthracnose (KLA) are caused by Colletotrichum acutatum. Both fungal isolates can infect flower petals, induce young fruit abscission and result in severe yield loss on many citrus cultivars. Previous studies revealed that infection of citrus flowers by C. acutatum caused higher levels of indole-3-acetic acid (IAA), which could be synthesized from the host plant and/or the fungal pathogen. The ability for IAA production by C. acutatum isolates was investigated. Similar to many microorganisms, the production of indole compounds in the medium by C. acutatum was dependent solely on the presence of tryptophan (Trp). In total, 14 PFD and KLA fungal isolates were tested, and revealed that they all were capable of utilizing Trp as a precursor to synthesize IAA and other indole derivatives. High-performance liquid chromatography analysis and chromogenic stains after a fluorescence thin-layer chromatography separation unambiguously identified IAA, tryptophol (TOL), indole-acetaldehyde, indole-acetamide (IAM), indole-pyruvic acid, and indole-lactic acid (ILA) from cultures supplemented with Trp. The data suggest that C. acutatum may synthesize IAA using various pathways. Interestingly, increasing Trp concentrations drastically increased the levels of TOL and ILA, but not IAA and IAM. The ability of C. acutatum to produce IAA and related indole compounds may in part contribute to the increased IAA levels in citrus flowers after infection.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Structure of the O-polysaccharide of Proteus mirabilis O19 and reclassification of certain Proteus strains that were formerly classified in serogroup O19.

INTRODUCTION: Bacteria of the genus Proteus are a common cause of urinary tract infections. The O-polysaccharide chain of their LPS (O-antigen) defines the serological specificity of these bacteria. Based on the immunospecificity of the O-antigens, two species, P. mirabilis and P. vulgaris, were classified into 49 O-serogroups, and more O-serogroups for strains of these species and P. penneri have been subsequently proposed. MATERIAL AND METHODS: The lipopolysaccharide of P.mirabilis CCUG 19011 from serogroup O19 was degraded under mildly acidic and mildly alkaline conditions. Polysaccharides thus obtained were studied by chemical methods, including O -deacetylation, sugar and methylation analyses, and 1H- and 13C-NMR spectroscopy. Antisera were obtained by immunization of New Zealand white rabbits with heat-killed bacteria. In serological studies, enzyme immunosorbent assay, passive hemolysis test, and inhibition of passive hemolysis were used. RESULTS: The following structure of the O-polysaccharide repeating unit was established:-->3)- beta-D-GlcrhoNAc-(1-->3)- alpha-D-GalrhoNAc4,6(R-Pyr)-(1-->4)- a-D-GalrhoA-(1-->3) alpha-L-Rhap2Ac-(1-->where R-Pyr is (R)-1-carboxyethylidene (an acetal-linked pyruvic acid). This structure is significantly different from the O-polysaccharide structures of P. vulgaris, P.hauseri and P. penneri strains from the same Proteus serogroup O19. CONCLUSIONS: Based on immunochemical studies of the lipopolysaccharides, it is suggested 1) to keep P. vulgaris CCUG 4654 and P. penneri 31 in serogroup O19 as two subgroups, 2) to reclassify P. mirabilis CCUG 19011 into a new Proteus serogroup, O51, and 3) to classify serologically related strains, including P. vulgaris ATCC 49990, P. hauseri> 1732-80 and 1086-80, P. penneri 15, and some other P. penneri strains, in yet another Proteus serogroup, O52.

Animals↗
PubMed1992

Insulin mediator stimulation of pyruvate dehydrogenase phosphatases.

A two stage assay for detecting insulin mediator based upon its stimulation of soluble pyruvate dehydrogenase (PDH) phosphatase to activate soluble pyruvate dehydrogenase complex (PDC) has been developed. This coupled assay determines the activation of PDC by monitoring production of [14C]CO2 from [1-14C]pyruvic acid. In addition to being more sensitive than the rat liver mitoplast assay previously used, it allows for the separation and investigation of the effects of mediator on the PDH phosphatases individually. It has been previously shown that the insulin mediator stimulates the most abundant PDH phosphatase, the divalent cation dependent PDH phosphatase, by decreasing the phosphatase's metal requirement (1). A metal independent PDH phosphatase has been found in bovine heart mitochondria. This phosphatase is not immunoprecipitated by antiphosphatase 2A antibody, it is not inhibited by okadaic acid, and it is not stimulated by spermine. However, it is stimulated (more than threefold) by insulin mediator prepared from isolated rat liver membranes. It is inhibited by Mg-ATP, with half-maximal inhibition at 0.3 mM; however, this inhibition is overcome by the insulin mediator.

Adenosine Triphosphate↗
PubMedDate not supplied

[Biogenic amines and the functional state of the liver in experimental allergic encephalomyelitis and postdiphtheritic polyneuritis in dogs].

Severity of paralytic syndrome correlated with impairments in some functions of liver tissue (bile secretion, concentrating and detoxicating capacities) as well as with content of biogenic amines, lactic and pyruvic acids in liver and in blood, flowing in and out the liver tissue in dogs with experimental allergic encephalomyelitis and with postdiphtheritic polyneuritis. The alterations observed were due to development of demyelinization in the nerves and to the effects of additional factors, caused by insufficiency in external respiration.

Amine Oxidase (Copper-Containing)↗
PubMed1987

Na-Stimulated Transport of l-Methionine in Brevibacterium linens CNRZ 918.

The transport of l-methionine by the gram-positive species Brevibacterium linens CNRZ 918 is described. The one transport system (K(m) = 55 muM) found is constitutive for l-methionine, stereospecific, and pH and temperature dependent. Entry of l-methionine into cells is controlled by the internal methionine pool. Competition studies indicate that l-methionine and alpha-aminobutyric acid share a common carrier for their transport. Neither methionine derivatives substituted on the amino or carboxyl groups nor d-methionine was an inhibitor, whereas powerful inhibition was shown by l-cysteine, s-methyl-l-cysteine, dl-selenomethionine and dl-homocysteine. Sodium plays important and varied roles in l-methionine transport by B. linens CNRZ 918: (i) it stimulates transport without affecting the K(m), (ii) it increases the specific activity (on a biomass basis) of the l-methionine transport system when present with methionine in the medium, suggesting a coinduction mechanism. l-Methionine transport requires an exogenous energy source, which may be succinic, lactic, acetic, or pyruvic acid but not glucose or sucrose. The fact that l-methionine transport was stimulated by potassium arsenate and to a lesser extent by potassium fluoride suggests that high-energy phosphorylated intermediates are not involved in the process. Monensin eliminates stimulation by sodium. Gramicidin and carbonyl cyanide-m-chlorophenylhydrazone act in the presence or absence of Na. N-Ethylmaleimide, p-chloromercurobenzoate, valinomycin, sodium azide, and potassium cyanide have no or only a partial inhibitory effect. These results tend to indicate that the proton motive force reinforced by the Na gradient is involved in the mechanism of energy coupling of l-methionine transport by B. linens CNRZ 918. Thus, this transport is partially similar to the well-described systems in gram-negative bacteria, except for the role of sodium, which is very effective in B. linens, a species adapted to the high sodium levels of its niche.

Journal Article↗
PubMed1966

Differential effects of deoxyribonucleotides on respiration of virulent pneumococci.

Firshein, William (Wesleyan University, Middletown, Conn.), Robert J. Erickson, and Bernadette A. Gargan. Differential effects of deoxyribonucleotides on respiration of virulent pneumococci. J. Bacteriol. 92:1645-1654. 1966.-Four naturally occurring deoxyribonucleotides affect respiration in three virulent pneumococcal types (Diplococcus pneumoniae) differentially. Deoxyadenylic acid (dAMP) stimulates respiration in type I and slightly stimulates respiration in type III, but has no effect in type II. Deoxyguanylic acid (dGMP) stimulates respiration in type I, inhibits respiration in type II, and has no effect in type III. Thymidylic acid (dTMP) inhibits respiration of type I, but is stimulatory in types II and III. Deoxycytidylic acid (dCMP) inhibits respiration of all three pneumococcal types. Of a large number of related compounds, including many of the naturally occurring deoxynucleosides, nucleosides, nucleotides, purines, and pyrimidines, thymidine is slightly effective in types II and III, and deoxycytidine is slightly inhibitory in all three types. None of the remaining compounds affects respiration significantly. With a few exceptions, there is a correlation between the extent of uptake of each deoxynucleotide in the three types and their ability to stimulate (or inhibit) respiration. The greater the uptake, the greater the enhancement of respiration. The less uptake, the greater the inhibition of respiration. In cell-free extracts of type I, dAMP also stimulates the oxidative decarboxylation of pyruvic acid. During this reaction, dAMP is phosphorylated to deoxyadenosine diphosphate (dADP) and to deoxyadenosine triphosphate (dATP).

Carbon Isotopes↗
PubMed1980

Improved Procedure for the Estimation of Nanogram Quantities of Indole-3-acetic Acid in Plant Extracts using the Indolo-alpha-pyrone Fluorescence Method.

The indolo-alpha-pyrone fluorescence method of determining indole-3-acetic acid (IAA) is improved by adding butylated hydroxytoluene (BHT), an antioxidant, to samples: addition of BHT increases the fluorescence intensities and decreases their variability so that amounts of IAA as small as 0.1 to 1 nanogram become measurable. Interfering compounds, 4-chloroindole-3-acetic acid and 5-hydroxyindole-3-acetic acid, can be separated from IAA by thin-layer chromatography using polyamide as the solid support, and benzene-ethyl acetate-acetic acid (70:25:5, v/v) as the developing solvent. Polyamide thin-layer chromatography is also superior in purifying IAA without significant loss or decomposition.A serious problem in extracting IAA from plant tissues is the considerable loss. Losses can result from decomposition of IAA when its solutions in organic solvents are evaporated to dryness, apparently due to some impurity in the solvents. Decomposition can be eliminated by simple treatments of the solvents, i.e. addition of BHT, washing with water, and passage through cotton wool. The latter is particularly effective in the case of ethyl acetate and ether. Loss of IAA by photodecomposition is also substantial even in dried samples. Ways to minimize the conversion of indole-3-pyruvic acid to IAA during extraction procedure are also described.A revised procedure of IAA extraction and determination is proposed. Applied to etiolated shoots of maize seedlings, it enables content to be estimated (18 nanograms per gram fresh weight) with over 90% recovery in terms of [(14)C]IAA added at the beginning of the extraction.

Journal Article↗
PubMedDate not supplied

[Effect of etimizol, caffeine and theophylline on some carbohydrate metabolic indices of the rat brain and myocardium].

Intraperitoneal administration of aethimizol (25 mg/kg) was seen to bring down the quantity of glycogen, to raise the level of lactic and pyruvic acids and to increase the ration of lactate/pyruvate in the brain tissue of the rat. Caffeine and theophylline (25 mg/kg) caused similar, but not so pronounced changes in the content of the said substrates. All the 3 agents--aethimizol, caffeine and theophylline had some effect on the metabolic processes in the heart muscle.

Animals↗
PubMed1978

Studies on the influence of ochratoxin A on rat lenses.

The influence of ochratoxin A on enzyme activities and on the content of free adenine nucleotides and intermediates of glycolysis in rat lenses was investigated. For a period of eight weeks, five times weekly, albino Wistat rats received ochratoxin A in 0.1% NaHCO3, dosed 1/100 LD50, via stomach tube. All measurements were made at the end of the experiment. Decreased contents of ATP, G-6-P, sum of fructose, and F-6-P were observed, but pyruvic acid, AMP, and DAP increased. Relatively decreased activities of enzymes MDH, ALD, HK, GK, and PK were established. The influence of ochratoxin A on the carbohydrate metabolism of rat lenses with respect to tranparency is discussed. There were no significant differences in absolute lens weight in animals treated by ochratoxin A and controls.

Adenosine Diphosphate↗
PubMed1998

Crystal structure of tryptophanase.

The X-ray structure of tryptophanase (Tnase) reveals the interactions responsible for binding of the pyridoxal 5'-phosphate (PLP) and atomic details of the K+ binding site essential for catalysis. The structure of holo Tnase from Proteus vulgaris (space group P2(1)2(1)2(1) with a = 115.0 A, b = 118.2 A, c = 153.7 A) has been determined at 2.1 A resolution by molecular replacement using tyrosine phenol-lyase (TPL) coordinates. The final model of Tnase, refined to an R-factor of 18.7%, (Rfree = 22.8%) suggests that the PLP-enzyme from observed in the structure is a ketoenamine. PLP is bound in a cleft formed by both the small and large domains of one subunit and the large domain of the adjacent subunit in the so-called "catalytic" dimer. The K+ cations are located on the interface of the subunits in the dimer. The structure of the catalytic dimer and mode of PLP binding in Tnase resemble those found in aspartate amino-transferase, TPL, omega-amino acid pyruvate aminotransferase, dialkylglycine decarboxylase (DGD), cystathionine beta-lyase and ornithine decarboxylase. No structural similarity has been detected between Tnase and the beta 2 dimer of tryptophan synthase which catalyses the same beta-replacement reaction. The single monovalent cation binding site of Tnase is similar to that of TPL, but differs from either of those in DGD.

Amino Acid Sequence↗
PubMed2004

Exploration of pressure-induced dissociation of pyruvate oxidase.

The dissociation of pyruvate oxidase (PO) caused by pressure up to 220 MPa at various conditions was explored by measuring the intrinsic fluorescence spectra and polarization. At 5 degrees C and pH 7.6 the standard volume change (deltaV0) and free energy upon dissociation of the enzyme is -220 ml/mol and 29.83 kCal/mol, respectively. It was found that FAD was irreversibly removed during the pressure-dissociation of the enzyme. A much smaller standard volume change (-153 ml/mol) and lower free energy (24.92 kCal/mol) of apo-pyruvate oxidase (apo-PO) compared with the native enzyme indicated that FAD played very important role in stabilizing the enzyme and significantly influenced the standard volume change. The substrate pyruvic acid can significantly stabilize the enzyme against pressure in spite the standard volume for the enzyme in this case has a big increase relative to the native enzyme. The comparison of the intrinsic fluorescence of the native and the activated enzyme obtained by limited proteolysis indicated that the physical separation of alpha-peptide from the enzyme only occurred when the subunits were dissociated from each other under pressure.

Enzyme Stability↗
PubMed1983

[Evaluation of cardiac function in patients with ischemic heart disease in the early stages of controlled physical exercise].

Fifty-nine coronary patients and 20 clinically normal subjects were investigated. Coronarography was performed in 21 patients. Everybody was referred to one of the three functional classes. Central hemodynamic parameters were measured using tetrapolar chest rheography. Venous levels of lactic and pyruvic acids were also measured. The measurements were taken in resting conditions and under threefold increase in systemic oxygen consumption following bicycle ergometry in supine position. Three types of response were identified: normal, compensated and decompensated ones. On the basis of these, functional reserves of the heart can be evaluated at earlier stages of rationed exercise, this being particularly important for coronary patients not to be exposed to maximum and submaximum physical stress.

Coronary Disease↗
PubMed1976

Effects of aminonucleoside, daunomycin, and adriamycin on carbon oxidation by glomeruli.

The purpose of these experiments was to determine whether reported changes in substrate metabolism by isolated glomeruli from rats with aminonucleoside nephrosis could be explained by the glomerular changes associated with proteinuria or, alternatively, whether these metabolic changes and proteinuria were synchronous but causally unrelated events. Aminonucleoside of puromycin produced proteinuria within 7 days when injected intraperitoneally or subcutaneously. However, when aminonucleoside of puromycin as well as adenine were given, the onset of proteinuria was delayed until after day 7. A significant reduction in U-14C-glucose oxidation to CO2 was found at day 7 by glomeruli from rats given aminonucleoside of puromycin intraperitoneally but no significant changes were found with aminonucleoside of puromycin given subcutaneously on days 7 and 9 and aminonucleoside of puromycin + adenine given subcutaneously on days 7 and 9. Rats given daunomycin or adriamycin had developed proteinuria by day 14. U-14C-glucose oxidation to CO2 was significantly reduced on day 14 in glomeruli from rats given daunomycin but no significant changes were found on day 21 with daunomycin, or on days 14 and 21 with adriamycin. There was a reduction in pyruvic-acid carbon metabolism but not in glutamine-carbon oxidation 14 days after treatment with daunomycin. These results suggest that the observed changes in glomerular metabolism occur independently of, albeit synchronous with, the development of proteinuria. A causal relationship between these metabolic alterations and proteinuria therefore may be unlikely.

Adenine↗
PubMedDate not supplied

Diurnal changes in the metabolic indices in the blood of racing Arabian horses.

In 8 stallions and 6 mares of pure Arabian breed the diurnal changes in the levels of lactic and pyruvic acid, glucose, and alkaline reserve were studied. All of them showed distinct diurnal changes but they failed to fulfil the criteria of circadian rhythm according to Halberg. It was found that all peaks occurred during the dark phase of the 24 h period except the glucose level in the stallions. Three of the indices studied showed higher mean diurnal levels in the mares than in the stallions. Only in the glucose level the mean values were reversed.

Adaptation, Physiological↗
PubMedDate not supplied

[Artificial arterial hypotension during surgical treatment of intracranial aneurysms].

In studying the content of lactic and pyruvic acids in the cerebrospinal fluid of 31 patients during operation for intracranial aneurysms under halothane anesthesia, the authors established that the performance of these operations under protection of deep (40 mm Hg) and prolonged (up to 2 hrs 25 min) artificial arterial hypotension in an uncomplicated course of the surgical intervention was not attended with hypoxic damage of the brain. The danger of hypoxia developing became greater when acute disturbances of blood flow in the cerebral arteries (clipping of a vessel, spasm) occurred in the period of hypotension.

Adult↗
PubMed1977

[Effect of hexahydroubiquinone-4 (KoQ4) on the bioenergetics and functional activity of the myocardium in ischemia].

The effect of KoQ4 on the energetics, contractility, and electrogram of the ischemized myocardium was studied in acute experiments on dogs with induced myocardial ischemia. Intracornoary administration of KoQ4, 1.3 mg/kg, directly into the focus of ischemia for 15 min promoted a decrease in the lactate level in blood draining from the ischemic zone as compared to the control data in the absence of a difference in the dynamics of the pyruvic acid content. In distinction to the control experimental series, there was no decrease in the concentration of glucose in samples of venous blood draining from the focus of ischemia. Under the effect of KoQ4 the amplitude of left ventricular pressure and the maximum rate of its growth (dp/dt) increased moderately and the ST segment and ST/R coefficient of the epicardial electrogram from the border zone of ischemia decreased. It was shown in the rat experiments that preliminary intravenous administration of KoQ4 (14 mg/kg) increased myocardial resistance to oxygen deficiency under conditions of diacetylcholine-induced apnoe.

Acute Disease↗
PubMed1990

Effects of amino acids on acute alcohol intoxication in mice--concentrations of ethanol, acetaldehyde, acetate and acetone in blood and tissues.

Condensation reactions between some SH-amino acids (L-and D-cysteine 1%) and acetaldehyde (50 microM) were studied in vitro experiment. In the aqueous solution, free acetaldehyde was reduced to 41.3% by L-cysteine and to 36.4% by D-cysteine. In the reaction with human blood medium, after the medium was deproteinized with perchloric acid reagent, acetaldehyde was reduced to 47.0% by L-cysteine and to 43.8% by D-cysteine. D-Cysteine appears to have great stability of reacting acetaldehyde. In vitro experiment reactability for D-cysteine exhibited 3-8% higher than that for L-cysteine. Next, effects of some amino acids on alcohol metabolism were studied in male ICR mice. The animals were given ethanol through a gastric catheter at a dose of 2 g/kg and they were intraperitoneally injected L-cysteine (300 mg/kg), D-cysteine (300 mg/kg), L-alanine (300 mg/kg) and control (saline), respectively in the period of one hour before the injection of ethanol. Blood and tissues samples were analyzed for ethanol, acetaldehyde, acetate and acetone during alcohol intoxication in mice by head space gas chromatography. In the groups administered D-cysteine and L-cysteine, the mice showed a definitely faster oxidation and disappearance of ethanol. Especially in the D-cysteine group, ethanol levels in blood, liver and brain remained lower than that in the other groups (p less than 0.01). Acetaldehyde levels in blood, liver and brain remained low by L-cysteine. Ethanol metabolites during alcohol oxidation by chemical reactabilities of L- and D-cysteine showed different distribution in the mice, respectively. In the mice received L-alanine, acetate and acetone levels in blood, liver and brain were distinctly reduced (p less than 0.01). L-Alanine is reported to supply an abundance of pyruvic acid that performs the NAD-generating system. NAD produced is introduced to alcohol metabolism and the TCA cycle. It was thus presumed that the L- or/and D-cysteine, and L-alanine was effective in acute alcohol intoxication by heavy drinking.

Acetaldehyde↗