Pathways of glucose catabolism in Mycobacterium smegmatis

1976 ◽  
Vol 22 (9) ◽  
pp. 1374-1380 ◽  
Author(s):  
N. Jayanthi Bai ◽  
M. Ramachandra Pai ◽  
P. Suryanarayana Murthy ◽  
T. A. Venkitasubramanian
Keyword(s):  
Glucose Metabolism ◽  
Carbon Source ◽  
Pentose Phosphate Pathway ◽  
Mycobacterium Smegmatis ◽  
Pentose Phosphate ◽  
Minor Role ◽  
Key Enzymes ◽  
Glucose Catabolism ◽  
A Minor ◽  
Cells Cultured

Glucose metabolism in Mycobacterium smegmatis was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Glucose is oxidized in this organism mainly through the Embden–Meyerhof–Parnas pathway, irrespective of the carbon source used for growth. The pentose phosphate pathway plays only a minor role and its extent depends on the carbon source used for growth. Enzymes of glycolytic and oxidative pathways were detected in cells grown on glucose, glycerol, or pyruvate but enzymes of the Entner–Doudoroff pathway could be detected only in glucose-grown cells. Labeled acetate is utilized by cells cultured on glucose, glycerol, and pyruvate. In all cases more of C1 of acetate was converted to CO2 while incorporation into cellular constituents was maximum from C2 of acetate.

Pentose phosphate pathway in cellular trophoblasts from full-term human placentas

1991 ◽  
Vol 261 (6) ◽  
pp. C1042-C1047 ◽  
Author(s):  
A. J. Moe ◽  
D. R. Farmer ◽  
D. M. Nelson ◽  
C. H. Smith
Keyword(s):  
Amino Acids ◽  
Methylene Blue ◽  
Glucose Metabolism ◽  
Electron Acceptor ◽  
Pentose Phosphate Pathway ◽  
Cultured Cells ◽  
Minor Component ◽  
Pentose Phosphate ◽  
Full Term ◽  
A Minor

Glucose metabolism was investigated in cellular trophoblasts isolated from full-term human placentas. The specific yields of 14CO2 from D-[1-14C]glucose and D-[6-14C]glucose were used to determine glucose metabolism via the pentose cycle for cells freshly isolated or cells grown in culture for 1 and 3 days. Cells were mononucleated on day 1 but fused to form multinucleated syncytiotrophoblasts by day 3. The principal product of glucose metabolism under all conditions was lactate, accounting for approximately three-fourths of recovered 14C in products. Pentose cycle activity contributed 0.57 +/- 0.01, 0.39 +/- 0.06, and 0.21 +/- 0.05% of the glucose metabolized by cells freshly isolated, cultured for 1 day, and cultured for 3 days, respectively. In the presence of the electron acceptor methylene blue, pentose cycle activity increased to 16.5 +/- 2.1, 13.8 +/- 1.5, and 18.2 +/- 1.7% for cells freshly isolated, cultured for 1 day, and cultured for 3 days, respectively. Trace amounts of 14C were recovered in other products including amino acids and glycogen. These data suggest that pentose cycle activity in cellular trophoblasts from full-term placenta, like those in full-term villous tissue, is a minor component of glucose metabolism. However, these cultured cells maintain a capacity to oxidize glucose via the pentose cycle at relatively high rates.

scholarly journals The Pentose Phosphate Pathway in Yeasts–More Than a Poor Cousin of Glycolysis

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 725
Author(s):  
Laura-Katharina Bertels ◽  
Lucía Fernández Murillo ◽  
Jürgen J. Heinisch
Keyword(s):  
Pentose Phosphate Pathway ◽  
Kluyveromyces Lactis ◽  
Aromatic Amino Acids ◽  
Pentose Phosphate ◽  
Minor Role ◽  
Disease Genes ◽  
Yeast Saccharomyces Cerevisiae ◽  
Key Enzyme ◽  
A Minor ◽  
Glucose 6 Phosphate Dehydrogenase

The pentose phosphate pathway (PPP) is a route that can work in parallel to glycolysis in glucose degradation in most living cells. It has a unidirectional oxidative part with glucose-6-phosphate dehydrogenase as a key enzyme generating NADPH, and a non-oxidative part involving the reversible transketolase and transaldolase reactions, which interchange PPP metabolites with glycolysis. While the oxidative branch is vital to cope with oxidative stress, the non-oxidative branch provides precursors for the synthesis of nucleic, fatty and aromatic amino acids. For glucose catabolism in the baker’s yeast Saccharomyces cerevisiae, where its components were first discovered and extensively studied, the PPP plays only a minor role. In contrast, PPP and glycolysis contribute almost equally to glucose degradation in other yeasts. We here summarize the data available for the PPP enzymes focusing on S. cerevisiae and Kluyveromyces lactis, and describe the phenotypes of gene deletions and the benefits of their overproduction and modification. Reference to other yeasts and to the importance of the PPP in their biotechnological and medical applications is briefly being included. We propose future studies on the PPP in K. lactis to be of special interest for basic science and as a host for the expression of human disease genes.

scholarly journals The Effect of Phytohemagglutinin upon Glucose Catabolism in Lymphocytes

Blood ◽  
1967 ◽  
Vol 29 (4) ◽  
pp. 640-646 ◽  
Author(s):  
R. A. MACHAFFIE ◽  
C. H. WANG ◽  
Julia Woransberg ◽  
Jackie Spangler
Keyword(s):  
Glucose Metabolism ◽  
Mitotic Activity ◽  
Pentose Phosphate Pathway ◽  
Pentose Phosphate ◽  
Glucose Catabolism

Abstract The glucose metabolism in intact lymphocyte cells was found to be altered in the presence of phytohemagglutinin. The operation of the pentose phosphate pathway and, to some extent, the pentose cycle pathway in lymphocytes was found to be significantly enhanced. This finding is interpreted to reflect an additional need of biosynthetic intermediates and TPNH by the lymphocytes to accommodate mitotic activity induced by phytohemagglutinin.

scholarly journals Transport and Catabolism of Carbohydrates by Neisseria meningitidis

2016 ◽  
Vol 26 (5) ◽  
pp. 320-332 ◽  
Author(s):  
Meriem Derkaoui ◽  
Ana Antunes ◽  
Jamila Nait Abdallah ◽  
Sandrine Poncet ◽  
Alain Mazé ◽  
...  
Keyword(s):  
Carbon Source ◽  
Transgenic Mice ◽  
Neisseria Meningitidis ◽  
Pentose Phosphate Pathway ◽  
Sole Carbon Source ◽  
Minimal Medium ◽  
Pentose Phosphate ◽  
Key Enzymes ◽  
The Real ◽  
Genes Encoding

We identified the genes encoding the proteins for the transport of glucose and maltose in <i>Neisseria meningitidis</i> strain 2C4-3. A mutant deleted for <i>NMV_1892</i><i>(glcP)</i> no longer grew on glucose and deletion of <i>NMV_0424</i><i>(malY)</i> prevented the utilization of maltose. We also purified and characterized glucokinase and α-phosphoglucomutase, which catalyze early catabolic steps of the two carbohydrates. <i>N. meningitidis</i> catabolizes the two carbohydrates either via the Entner-Doudoroff (ED) pathway or the pentose phosphate pathway, thereby forming glyceraldehyde-3-P and either pyruvate or fructose-6-P, respectively. We purified and characterized several key enzymes of the two pathways. The genes required for the transformation of glucose into gluconate-6-P and its further catabolism via the ED pathway are organized in two adjacent operons. <i>N. meningitidis</i> also contains genes encoding proteins which exhibit similarity to the gluconate transporter <i>(NMV_2230)</i> and gluconate kinase <i>(NMV_2231)</i> of Enterobacteriaceae and Firmicutes. However, gluconate might not be the real substrate of <i>NMV_2230</i> because <i>N. meningitidi</i>s was not able to grow on gluconate as the sole carbon source. Surprisingly, deletion of <i>NMV_2230</i> stimulated growth in minimal medium in the presence and absence of glucose and drastically slowed the clearance of <i>N. meningitidis</i> cells from transgenic mice after intraperitoneal challenge.

scholarly journals Insulin stimulates glucose metabolism via the pentose phosphate pathway in Drosophila Kc cells

FEBS Letters ◽  
2003 ◽  
Vol 555 (2) ◽  
pp. 307-310 ◽  
Author(s):  
Rolando B. Ceddia ◽  
George J. Bikopoulos ◽  
Arthur J. Hilliker ◽  
Gary Sweeney
Keyword(s):  
Glucose Metabolism ◽  
Pentose Phosphate Pathway ◽  
Pentose Phosphate

The effects of acetate and of pyruvate on the pathways of glucose catabolism in lactating mammary tissue. II. Sheep tissue

1969 ◽  
Vol 36 (3) ◽  
pp. 469-478 ◽  
Author(s):  
R. W. Smith ◽  
R. F. Glascock
Keyword(s):  
Pentose Phosphate Pathway ◽  
Acid Synthesis ◽  
Pentose Phosphate ◽  
Mammary Tissue ◽  
Glucose Catabolism ◽  
Glucose Carbon ◽  
Rat Tissue ◽  
The Relationship ◽  
Stimulation Of

SummaryA study was made of the changes in the rates of oxidation of the C(1), C(2) and C(6) atoms of glucose and in the pathways of glucose catabolism in sheep udder tissue in vitro which occurred when acetate and pyruvate were added.Whereas in rat mammary tissue the rate of oxidation of the C(1) atom of glucose was very much greater than that of the C(6) atom, the ratio of the rates of oxidation of these 2 atoms in sheep tissue was less than 2 when glucose was the only substrate.The addition of acetate resulted in an unequal stimulation of the oxidation of these 2 atoms, with the result that the ratio of their rates of oxidation was about doubled. The rate of oxidation of the C(2) atom was also increased.Acetate also increased the participation of the pentose phosphate pathway in glucose catabolism as measured by the incorporation of the C(1) and C(6) atoms of glucose into fatty acids, lactic acid and glycerol.Pyruvate produced little effect on the rate of oxidation of the C(1) atom but somewhat depressed that of the C(6) atom of glucose. At the same time, it caused a large increase in the participation of the pentose phosphate pathway.These results are discussed with reference to re-cycling of glucose carbon in the pentose phosphate pathway and to the relationship between that pathway and fatty acid synthesis. It is noted that the incorporation of glucose carbon into the 3 intermediates used gave values for the participation of that pathway which were in better agreement than was obtained in rat tissue. It is concluded that triose phosphates are more nearly in equilibrium in sheep than in rat mammary tissue.

scholarly journals Metabolic Changes Induced by Deletion of Transcriptional Regulator GCR2 in Xylose-Fermenting Saccharomyces cerevisiae

2020 ◽  
Vol 8 (10) ◽  
pp. 1499
Author(s):  
Minhye Shin ◽  
Soo Rin Kim
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Transcriptional Regulator ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Metabolic Changes ◽  
Regulatory Systems ◽  
Central Carbon

Glucose repression has been extensively studied in Saccharomyces cerevisiae, including the regulatory systems responsible for efficient catabolism of glucose, the preferred carbon source. However, how these regulatory systems would alter central metabolism if new foreign pathways are introduced is unknown, and the regulatory networks between glycolysis and the pentose phosphate pathway, the two major pathways in central carbon metabolism, have not been systematically investigated. Here we disrupted gcr2, a key transcriptional regulator, in S. cerevisiae strain SR7 engineered to heterologously express the xylose-assimilating pathway, activating genes involved in glycolysis, and evaluated the global metabolic changes. gcr2 deletion reduced cellular growth in glucose but significantly increased growth when xylose was the sole carbon source. Global metabolite profiling revealed differential regulation of yeast metabolism in SR7-gcr2Δ, especially carbohydrate and nucleotide metabolism, depending on the carbon source. In glucose, the SR7-gcr2Δ mutant showed overall decreased abundance of metabolites, such as pyruvate and sedoheptulose-7-phosphate, associated with central carbon metabolism including glycolysis and the pentose phosphate pathway. However, SR7-gcr2Δ showed an increase in metabolites abundance (ribulose-5-phosphate, sedoheptulose-7-phosphate, and erythrose-4-phosphate) notably from the pentose phosphate pathway, as well as alteration in global metabolism when compared to SR7. These results provide insights into how the regulatory system GCR2 coordinates the transcription of glycolytic genes and associated metabolic pathways.

scholarly journals The Pentose Phosphate Pathway and Pyruvate Carboxylation after Neonatal Hypoxic-Ischemic Brain Injury

2014 ◽  
Vol 34 (4) ◽  
pp. 724-734 ◽  
Author(s):  
Eva MF Brekke ◽  
Tora S Morken ◽  
Marius Widerøe ◽  
Asta K Håberg ◽  
Ann-Mari Brubakk ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Glucose Metabolism ◽  
Pentose Phosphate Pathway ◽  
De Novo ◽  
Pentose Phosphate ◽  
Adult Brain ◽  
Resonance Spectroscopy ◽  
Neonatal Brain ◽  
Artery Ligation ◽  
Pyruvate Carboxylation

The neonatal brain is vulnerable to oxidative stress, and the pentose phosphate pathway (PPP) may be of particular importance to limit the injury. Furthermore, in the neonatal brain, neurons depend on de novo synthesis of neurotransmitters via pyruvate carboxylase (PC) in astrocytes to increase neurotransmitter pools. In the adult brain, PPP activity increases in response to various injuries while pyruvate carboxylation is reduced after ischemia. However, little is known about the response of these pathways after neonatal hypoxia-ischemia (HI). To this end, 7-day-old rats were subjected to unilateral carotid artery ligation followed by hypoxia. Animals were injected with [1,2-13C]glucose during the recovery phase and extracts of cerebral hemispheres ipsi- and contralateral to the operation were analyzed using 1H- and 13C-NMR (nuclear magnetic resonance) spectroscopy and high-performance liquid chromatography (HPLC). After HI, glucose levels were increased and there was evidence of mitochondrial hypometabolism in both hemispheres. Moreover, metabolism via PPP was reduced bilaterally. Ipsilateral glucose metabolism via PC was reduced, but PC activity was relatively preserved compared with glucose metabolism via pyruvate dehydrogenase. The observed reduction in PPP activity after HI may contribute to the increased susceptibility of the neonatal brain to oxidative stress.

scholarly journals Wnt5a Increases the Glycolytic Rate and the Activity of the Pentose Phosphate Pathway in Cortical Neurons

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Pedro Cisternas ◽  
Paulina Salazar ◽  
Carmen Silva-Álvarez ◽  
L. Felipe Barros ◽  
Nibaldo C. Inestrosa
Keyword(s):  
Glucose Metabolism ◽  
Wnt Signaling ◽  
Pentose Phosphate Pathway ◽  
Neurodegenerative Disorders ◽  
Metabolic Flux ◽  
High Energy ◽  
Pentose Phosphate ◽  
The Brain ◽  
Glycolytic Rate

In the last few years, several reports have proposed that Wnt signaling is a general metabolic regulator, suggesting a role for this pathway in the control of metabolic flux. Wnt signaling is critical for several neuronal functions, but little is known about the correlation between this pathway and energy metabolism. The brain has a high demand for glucose, which is mainly used for energy production. Neurons use energy for highly specific processes that require a high energy level, such as maintaining the electrical potential and synthesizing neurotransmitters. Moreover, an important metabolic impairment has been described in all neurodegenerative disorders. Despite the key role of glucose metabolism in the brain, little is known about the cellular pathways involved in regulating this process. We report here that Wnt5a induces an increase in glucose uptake and glycolytic rate and an increase in the activity of the pentose phosphate pathway; the effects of Wnt5a require the intracellular generation of nitric oxide. Our data suggest that Wnt signaling stimulates neuronal glucose metabolism, an effect that could be important for the reported neuroprotective role of Wnt signaling in neurodegenerative disorders.

Sign in / Sign up

Export Citation Format

Share Document