The Pathway of Glucose Catabolism in Sporocytophaga myxococcoides

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 27-35 ◽  
Author(s):  
A. O. Hanstveit ◽  
J. Goksøyr
Keyword(s):  
Enzyme Activity ◽  
Acetic Acid ◽  
Glucose Metabolism ◽  
Pyruvic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Catabolic Pathways ◽  
Acid Cycle ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Pentose Pathway

The pathway of glucose metabolism in Sporocytophaga myxococcoides was studied by a radiorespirometric technique and assays of enzyme activity in cell-free extracts. The primary catabolic pathways in the organism were examined by measurement of relative rates of 14CO2-production from different carbon atoms of labelled glucose, pyruvic acid and acetic acid. These substrates appeared to be degraded solely by enzymes of the Embden-Meyerhof-Parnas pathway in conjunction with the tricarboxylic acid cycle. The results were confirmed by studies of enzyme activity, which showed a lack of two enzymes, glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate dehydrogenase, EC. 1.1.1.49) and 6-phospho-gluconate dehydrogenase [6-phospho-D-gluconate: NADP oxidoreductase (decarboxylating), EC. 1.1.1.44], in the pentose pathway, which indicated a biosynthetic function of the non-oxidative part of this pathway.

scholarly journals Glucose metabolism and its regulation in pieces of perirenal adipose tissue from foetal lambs

1983 ◽  
Vol 210 (3) ◽  
pp. 677-683 ◽  
Author(s):  
J P Robertson ◽  
A Faulkner ◽  
R G Vernon
Keyword(s):  
Adipose Tissue ◽  
Glucose Metabolism ◽  
Pyruvate Dehydrogenase ◽  
Glucose Utilization ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Acid Cycle ◽  
Near Term ◽  
Glucose 6 Phosphate Dehydrogenase

1. The following were measured in pieces of perirenal adipose tissue obtained from foetal lambs at about 120 days of gestation or within 3 days of term, and 9-month-old sheep: the rates of synthesis from glucose of fatty acids, acylglycerol glycerol, pyruvate and lactate; the rate of glucose oxidation to CO2 and the proportions contributed by the pentose phosphate cycle, pyruvate dehydrogenase and the tricarboxylic acid cycle; the activities of hexokinase, glucose 6-phosphate dehydrogenase, phosphofructokinase, pyruvate kinase and pyruvate dehydrogenase. 2. The total rate of glucose utilization was lower in pieces of adipose tissue from near-term lambs than 120-day foetal lambs and the pattern of glucose metabolism differed, with, for example, a much smaller proportion of glucose carbon being used for fatty acid synthesis, whereas a greater proportion of glucose oxidation occurred via the tricarboxylic acid cycle in the near-term lambs. In general, these differences in glucose metabolism were not associated with differences in the activities of the various enzymes listed above. 3. The rates of glucose utilization per fat-cell by 120-day foetal lambs and 9-month-old sheep were very similar but, again, the proportions metabolized to the various products differed. In particular, there was a smaller proportion of glucose oxidized via the pentose phosphate cycle and a greater proportion oxidized via pyruvate dehydrogenase and the tricarboxylic acid cycle in adipose tissue from foetal lambs. These differences were matched by a lower activity of glucose 6-phosphate dehydrogenase and a higher pyruvate dehydrogenase activity in fat-cells from the foetal lambs.

Modulation of glucose metabolism in macrophages by products of nitric oxide synthase

1993 ◽  
Vol 264 (6) ◽  
pp. C1594-C1599 ◽  
Author(s):  
J. E. Albina ◽  
B. Mastrofrancesco
Keyword(s):  
Nitric Oxide ◽  
Glucose Metabolism ◽  
Oxidative Metabolism ◽  
Culture Media ◽  
Tricarboxylic Acid Cycle ◽  
Specific Inhibitor ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
The Impact ◽  
By Products

Nitric oxide (NO) is a product of L-arginine metabolism that suppresses cellular oxidative metabolism through the inhibition of tricarboxylic acid cycle and electron transport chain enzymes. The impact of NO synthase (NOS) activity on specific pathways of glucose metabolism in freshly harvested and overnight-cultured rat resident peritoneal macrophages, at rest and after stimulation with zymosan, was investigated using radiolabeled glucose. NOS activity was modulated through the L-arginine concentration in culture media and the use of its specific inhibitor, NG-monomethyl-L-arginine, and quantitated using radiolabeled L-arginine. Results demonstrated that NOS activity was associated with increased glucose disappearance, glycolysis, and hexose monophosphate shunt activity and, in line with the known inhibition of oxidative metabolism associated with the production of NO, with a decrease in the flux of glucose and butyrate carbon through the tricarboxylic acid cycle. In addition, the relative increase in glucose utilization that follows zymosan stimulation was enhanced by treatments that suppressed NOS activity. These results demonstrate that the characteristics of glucose metabolism by macrophages are, to a significant extent, determined by products of NOS.

SODIUM REQUIREMENT OF POLY-β-HYDROXYBUTYRIC ACID DEPOLYMERASE OF MICROCOCCUS HALODENITRIFICANS

1963 ◽  
Vol 9 (4) ◽  
pp. 491-497 ◽  
Author(s):  
G. Sierra ◽  
N. E. Gibbons
Keyword(s):  
Enzyme Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Lithium Salts ◽  
Hydroxybutyric Acid ◽  
Moderate Halophile ◽  
Acid Cycle

Cells of Micrococcus kalodenitrificans, a moderate halophile, contain poly-β-hydroxybutyric acid (PHBA), which is oxidized endogenously when cells are suspended in NaCl. The oxidation involves a depolymerase, a DPN-linked D(−)-β-hydroxybutyric acid (HBA) dehydrogenase, and the enzymes of the tricarboxylic acid cycle. Cells suspended in NaBr, Na2SO4, Li2SO4, and LiCl oxidize PHBA but cells suspended in KCl, KBr, K2SO4, MgCl2, CaCl2, CsCl, glucose, or glycerol, iso-osmotic with 0.4 molal NaCl or in water or buffers do not. Since cells washed with and resuspended in KCl do not oxidize their internal PHBA, it seems that nearly all the cell Na+ has been replaced by K+. These cells can be reactivated by the addition of Na+ or Li+, indicating that these ions are required for enzyme activity. In Na-depleted cells or their extracts the dehydrogenation of HBA and the oxidation of acetate are unimpaired, but there is no PHBA depolymerase activity. PHBA depolymerase can be reactivated by the addition of Na+. The results indicate that sodium or lithium salts readily penetrate the cells of M. halodenitrificans and are required to activate the PHBA depolymerase.

scholarly journals Metabolic changes in the lymphocytes during influenza

2012 ◽  
Vol 93 (4) ◽  
pp. 580-584
Author(s):  
I V Sergeeva ◽  
N I Kamzalakova ◽  
E P Tikhonova ◽  
G V Bulygin
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Tricarboxylic Acid Cycle ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Tricarboxylic Acid ◽  
Nicotinamide Adenine ◽  
Control Group ◽  
Healthy Individuals ◽  
Acid Cycle ◽  
Intracellular Enzymes ◽  
Glucose 6 Phosphate Dehydrogenase

Aim. To assess the nature and intensity of metabolic processes in lymphocytes of patients with influenza according to the activity of intracellular enzymes in comparison to the severity of the disease. Methods. Determined were the enzymatic parameters of lymphocytes of 45 patients aged 18 to 42 years with a diagnosis of «influenza». Two groups of patients were formed: with moderate (24 patients) and severe (21 patients) course of the disease. Used as controls were the values the activity of intracellular enzymes of lymphocytes of 37 practically healthy individuals of comparable age. Results. In patients with a moderately severe course of the influenza compared with the controls noted was a significant increase in activity of glucose-6-phosphate dehydrogenase (3.17±0.53 and 2.74±0.31 mkE/10 000 cells, p 0.05) and glycerol-3-phosphate dehydrogenase (57.33±±5.65 and 0.84±0.16 mkE/10 000 cells respectively, p 0.001). The activity of lactate dehydrogenase was lower in patients than in controls (0.40±0.08 and 0.84±0.08 mkE/10 000 cells respectively, p 0.001). Indicators of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate dependant isocitrate dehydrogenases in lymphocytes of patients were lower than in the controls: the first indicator in the patients was 0.17±0.02 mkE/10 000 cells, in controls - 1.95±0.25 mkE/10 000 cells (p 0.001), and for the second indicator these values were respectively 0.09±0.01 and 31.02±±2.20 mkE/10 000 cells (p 0.001). In patients with a moderately severe course of influenza the activity of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate dependant glutamate dehydrogenases was significantly higher compared with healthy individuals: 63.67±5.32 and 0.34±0.06 mkE/10 000 cells, 1.45±0.18 and 0.11±0.02 mkE/10 000 cells respectively (p 0.001). The activity of nicotinamide adenine dinucleotide dependant malate dehydrogenase in patients was equal to 86.46±12.30 mkE/10 000 cells (in the control group 84.16±13.70 mkE/10 000 cells), and the activity of nicotinamide adenine dinucleotide phosphate dependant malate dehydrogenase was equal to 1.34±±0.25 mkE/10 000 cells (in the control group 0.33±0.07 mkE/10 000 cells, p 0.001). The activity of glutathione reductase was also higher in patients with the moderately severe course of the influenza: 5.86±0.25 mkE/10 000 cells, while the value in healthy individuals was 1.28±0.30 mkE/10 000 cells (p 0.001). In the group of patients with a severe course of influenza the activity of almost all (except for glucose-6-phosphate dehydrogenase) enzymes was higher than during the moderately severe course of disease. Conclusion. At the peak of the diseases noted were opposite changes in the activity of reactions of the pentose phosphate cycle and glycolysis. With a high functional load on the cells there is a significant reduction in the intensity of the reactions of the initial phase of the tricarboxylic acid cycle, which reduces the energy efficiency of the cycle, while the intense influx of metabolites to supply the tricarboxylic acid cycle with substrates of the amino acid metabolism provides enhanced transport of amino acids into the lymphocytes.

C14-labeled glucose metabolism by bone from normal and parathyroid-treated rats

1965 ◽  
Vol 208 (5) ◽  
pp. 1036-1041 ◽  
Author(s):  
Haripada Chattopadhyay ◽  
Smith Freeman
Keyword(s):  
Glucose Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Bone Matrix ◽  
Tricarboxylic Acid ◽  
Bicarbonate Buffer ◽  
Acid Cycle ◽  
Growing Rats ◽  
Parathyroid Extract ◽  
Tricarboxylic Acid Cycle Intermediates

Calvaria and the metaphyseal and epiphyseal sections of tibia and femora freed of bone marrow from young growing rats were incubated in vitro for 2 hr at 37 C in Krebs-Ringer bicarbonate buffer containing 2 mm glucose. The glucose was labeled either in the 1 position or in the 6 position or uniformly in all positions with C14. The incorporation of C14 into citrate, lactate, and various tricarboxylic acid cycle intermediates was studied. The release of C14O2 and the incorporation of C14 into bone matrix were also measured. Results obtained from bones of untreated control, parathyroid extract-treated, and parathyroidectomized animals were compared. It was found that treatment of animals with parathyroid extract increased the total accumulation of labeled citrate and malate as well as the incorporation of these acids into bone mineral. Bones from extract-treated animals also exhibited a significant decrease in the total accumulation of radioactive fumarate, succinate, and pyruvate. Lactate was the major end product of glucose metabolism, but its accumulation was only slightly influenced by parathyroid extract.

scholarly journals Enhanced Post-Stationary-Phase Survival of a Clinical Thymidine-Dependent Small-Colony Variant of Staphylococcus aureus Results from Lack of a Functional Tricarboxylic Acid Cycle

2007 ◽  
Vol 189 (7) ◽  
pp. 2936-2940 ◽  
Author(s):  
Indranil Chatterjee ◽  
Mathias Herrmann ◽  
Richard A. Proctor ◽  
Georg Peters ◽  
Barbara C. Kahl
Keyword(s):  
Staphylococcus Aureus ◽  
Acetic Acid ◽  
Acid Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Altered Expression ◽  
Acid Cycle ◽  
Small Colony Variant ◽  
Stationary Phase Survival ◽  
Small Colony

ABSTRACT The mechanisms underlying the persistence of the Staphylococcus aureus small-colony variant (SCV) are not fully elucidated. In this study, clinical thymidine-dependent SCVs displayed altered expression of citB, clpC, and arcA genes, reduced acetate catabolization, and enhanced survival. These results implicate the importance of changes in tricarboxylic acid cycle and acetic acid metabolism in SCV survival and persistence.

scholarly journals Biochemical adaptation in rat liver in response to marginal oxygen toxicity

1971 ◽  
Vol 125 (2) ◽  
pp. 439-447 ◽  
Author(s):  
R. R. Gorman ◽  
J. P. Jordan ◽  
J. B. Simmons ◽  
D. P. Clarkson
Keyword(s):  
Sea Level ◽  
Pentose Phosphate Pathway ◽  
Tricarboxylic Acid Cycle ◽  
Oxygen Toxicity ◽  
Liver Glycogen ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Acid Cycle ◽  
Biochemical Adaptation ◽  
Glucose 6 Phosphate Dehydrogenase

1. Hepatic glucose 6-phosphate dehydrogenase activity was increased in rats exposed to 5lb/in2 (equivalent to 27000ft), 100% O2 when compared with control animals in a 14.7lb/in2 (sea level), air environment. Glyceraldehyde 3-phosphate dehydrogenase, isocitrate dehydrogenase, and succinate dehydrogenase were not affected by the 5lb/in2, 100% O2 environment. 2. Animals exposed to the hyperoxic environment consumed food, expired CO2 and gained weight at the same rate as normoxic control animals. Additionally, blood glucose and liver glycogen concentrations were unchanged in the hyperoxic animals. The only readily apparent physiological difference in the hyperoxic animals was a decreased haematocrit. 3. The increase in glucose 6-phosphate dehydrogenase was eliminated by the injection of actinomycin D or cycloheximide. 4. Expiration of 14CO2 from [1-14C]glucose was approximately the same in hyperoxic and normoxic rats. However, 14CO2 expiration from [6-14C]glucose was markedly decreased in the animals exposed to the hyperoxic environment. 5. Calculations of the relative importance of the pentose phosphate pathway versus the tricarboxylic acid cycle plus glycolysis indicated that the livers from animals in the 5lb/in2, 100% O2 environment metabolized twice as much carbohydrate by way of the pentose phosphate pathway as did those from the sea-level air control animals. 6. In livers of rats exposed to 5lb/in2, 100% O2 the concentrations of pyruvate, citrate and 2-oxoglutarate were increased, that of isocitrate was slightly elevated, whereas the concentrations of succinate, fumarate and malate were decreased. 7. An inactivation of both tricarboxylic acid cycle lipoate-containing dehydrogenases, pyruvate and 2-oxoglutarate, under hyperoxic conditions is proposed. 8. The adaptive significance of the induction of glucose 6-phosphate dehydrogenase and the resultant production of NADPH under hyperoxic conditions is discussed.

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