Pathways of glucose catabolism in the smut fungus Ustilago violacea

1986 ◽  
Vol 32 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Gary Held ◽  
Manuel Goldman
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Smut Fungus ◽  
Enzyme Assays ◽  
Mating Types ◽  
Cycle Enzyme ◽  
Ustilago Violacea ◽  
Glucose Catabolism ◽  
The Glyoxylate Cycle

The pathways of glucose catabolism were examined in haploid and diploid strains of the smut fungus Ustilago violacea. Radiorespirometric studies indicated that both of the haploid mating types and diploid strains of this basidiomycete catabolized glucose through the Embden–Meyerhof and hexose monophosphate shunt pathways. The Entner–Doudoroff pathway was not utilized by any of the strains examined. Radiorespirometric data also suggested functioning of an active tricarboxylic acid cycle. In vitro enzyme assays established the presence in this organism of all the enzymes integral to the operative pathways plus the presence of the enzymes of the glyoxylate cycle. Enzyme activities specific to the Entner–Doudoroff pathway were not detected. No major differences in the routes of glucose dissimilation were found between the two haploid mating types or between haploid and diploid forms of this organism.

Photo-induction sexuée du pyrénomycète Nectria galligena: influence de la mycosporine sur le rapport des activités NADPM+-socitrate déshydrogénase/isocitrate lyase

1989 ◽  
Vol 67 (2) ◽  
pp. 447-450 ◽  
Author(s):  
B. Dehorter ◽  
L. Lacoste
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Nectria Galligena ◽  
Lyase Activity ◽  
Growth Of Fungi ◽  
The Glyoxylate Cycle

The activity of two enzymes of the tricarboxylic acid cycle (NADP+-isocitrate dehydrogenase, EC 1.1.1.42) and the glyoxylate cycle (isocitrate lyase, EC 4.1.3.1) were assayed in vitro to determine the effects of darkness, light, and mycosporin (P310) on sexual morphogenesis in Nectria galligena Bres. In the absence of mycosporin, high isocitrate lyase activity was associated with vegetative growth of fungi kept in the dark. In contrast, light-induced perithecial development and mycosporin biosynthesis could be correlated with high ratios of isocitrate dehydrogenase to isocitrate lyase activity. This was confirmed by the fact that when mycosporin was added to the nutrient medium with incubation in darkness, the fertility of the fungus was partially expressed and the activity of isocitrate lyase was significantly reduced. Thus this enzyme would be repressed in vivo by mycosporin. Because of its photomimetic role in sexual differentiation and regulation of intermediate metabolism, mycosporin appears to be a biochemical transmitter of light energy required for the formation of ascocarps.

Metabolic control in Acinetobacter sp. I. Effect of C4 versus C2 and C3 substrates on isocitrate lyase synthesis

1970 ◽  
Vol 16 (8) ◽  
pp. 769-774 ◽  
Author(s):  
Norma J. Herman ◽  
Emily J. Bell
Keyword(s):  
Carbon Source ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Specific Activity ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Enzyme Synthesis ◽  
Synthetase Activity ◽  
The Glyoxylate Cycle

The comparative effects of various substrates serving as sole carbon and energy source or as a supplemental nutrient on the synthesis of isocitrate lyase by a species of Acinetobacter have been investigated. Previous work has shown that succinate, as carbon source, allows some late, limited induction of enzyme synthesis. No increase in synthesis is seen above the basal level, however, in cultures growing in a medium containing L-malate as a sole carbon source. The addition of acetate to cultures growing in media containing either of the C4 intermediates results in rapid enzyme induction. Further, Acinetobacter grows very well in pyruvate medium and isocitrate lyase is synthesized to a significant extent, indicating that the glyoxylate cycle is acting anaplerotically under these conditions. Phosphoenolpyruvate synthetase activity has been demonstrated in this organism; levels comparable to those observed in Escherichia coli have been detected; the levels of NAD- and NADP-linked "malic enzyme" and phosphoenolpyruvate carboxykinase, enzymes functioning in C4 to C3 conversion, do not fluctuate with the various carbon sources tested; i.e. no correlation between the in vitro specific activity of these enzymes and the levels of isocitrate lyase activity may be made. All of the data are consistent with the hypothesis that, in this aerobic organism, as opposed to the facultative E. coli, the C4 intermediates of the tricarboxylic acid cycle may be more direct "coarse" control metabolites regulating the rate of the glyoxylate cycle.

The glyoxylate cycle enzyme activities in the pathogenic isolates of Candida albicans obtained from HIV/AIDS, diabetic and burn patients

Mycoses ◽  
2006 ◽  
Vol 49 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Ali Abdul Lattif ◽  
Rajendra Prasad ◽  
Uma Banerjee ◽  
Nivedita Gupta ◽  
Sameer Mohammad ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Enzyme Activities ◽  
Glyoxylate Cycle ◽  
Burn Patients ◽  
Cycle Enzyme ◽  
The Glyoxylate Cycle ◽  
Hiv Aids

scholarly journals Regulation of Gluconeogenesis in Saccharomyces cerevisiae Is Mediated by Activator and Repressor Functions of Rds2

2007 ◽  
Vol 27 (22) ◽  
pp. 7895-7905 ◽  
Author(s):  
Nitnipa Soontorngun ◽  
Marc Larochelle ◽  
Simon Drouin ◽  
François Robert ◽  
Bernard Turcotte
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Target Genes ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Dual Function ◽  
Snf1 Kinase ◽  
Zinc Cluster ◽  
Chip Technology

ABSTRACT In Saccharomyces cerevisiae, RDS2 encodes a zinc cluster transcription factor with unknown function. Here, we unravel a key function of Rds2 in gluconeogenesis using chromatin immunoprecipitation-chip technology. While we observed that Rds2 binds to only a few promoters in glucose-containing medium, it binds many additional genes when the medium is shifted to ethanol, a nonfermentable carbon source. Interestingly, many of these genes are involved in gluconeogenesis, the tricarboxylic acid cycle, and the glyoxylate cycle. Importantly, we show that Rds2 has a dual function: it directly activates the expression of gluconeogenic structural genes while it represses the expression of negative regulators of this pathway. We also show that the purified DNA binding domain of Rds2 binds in vitro to carbon source response elements found in the promoters of target genes. Finally, we show that upon a shift to ethanol, Rds2 activation is correlated with its hyperphosphorylation by the Snf1 kinase. In summary, we have characterized Rds2 as a novel major regulator of gluconeogenesis.

THE TRICARBOXYLIC ACID AND GLYOXYLATE CYCLES IN XANTHOMONAS PHASEOLI (XP8)

1959 ◽  
Vol 5 (1) ◽  
pp. 1-8 ◽  
Author(s):  
N. B. Madsen ◽  
R. M. Hochster
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Sole Source ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Main Pathway ◽  
The Individual ◽  
Acetate Medium ◽  
Terminal Oxidation ◽  
The Glyoxylate Cycle

Cell-free extracts of Xanthomonas phaseoli contain the individual enzymes of the tricarboxylic acid cycle, and it is suggested that this is the main pathway for the terminal oxidation of carbohydrate in this organism. X. phaseoli can grow on a medium containing acetate as the sole source of carbon. Cell-free extracts of such acetate-grown organisms contain the enzymes of the glyoxylate cycle, and it is concluded that the operation of this cycle permits the initial stages of synthesis of complex cell material from acetate at a rate sufficiently high to account for the observed rate of growth on the acetate medium. The two enzymes required to modify a tricarboxylic acid cycle into a glyoxylate cycle are present in very small amounts (malate synthetase) or absent entirely (isocitritase) in extracts of glucose-grown X. phaseoli.

scholarly journals Structure of glyoxysomal malate dehydrogenase (MDH3) from Saccharomyces cerevisiae

2018 ◽  
Vol 74 (10) ◽  
pp. 617-624 ◽  
Author(s):  
Shu Moriyama ◽  
Kazuya Nishio ◽  
Tsunehiro Mizushima
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Malate Dehydrogenase ◽  
Ternary Complex ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Tricarboxylic Acid ◽  
Mitochondrial Enzyme ◽  
Open Conformation ◽  
Metabolism Enzyme ◽  
The Glyoxylate Cycle

Malate dehydrogenase (MDH), a carbohydrate and energy metabolism enzyme in eukaryotes, catalyzes the interconversion of malate to oxaloacetate (OAA) in conjunction with that of nicotinamide adenine dinucleotide (NAD+) to NADH. Three isozymes of MDH have been reported in Saccharomyces cerevisiae: MDH1, MDH2 and MDH3. MDH1 is a mitochondrial enzyme and a member of the tricarboxylic acid cycle, whereas MDH2 is a cytosolic enzyme that functions in the glyoxylate cycle. MDH3 is a glyoxysomal enzyme that is involved in the reoxidation of NADH, which is produced during fatty-acid β-oxidation. The affinity of MDH3 for OAA is lower than those of MDH1 and MDH2. Here, the crystal structures of yeast apo MDH3, the MDH3–NAD+ complex and the MDH3–NAD+–OAA ternary complex were determined. The structure of the ternary complex suggests that the active-site loop is in the open conformation, differing from the closed conformations in mitochondrial and cytosolic malate dehydrogenases.

THE TRICARBOXYLIC ACID CYCLE, THE GLYOXYLATE CYCLE, AND THE ENZYMES OF GLUCOSE OXIDATION IN PSEUDOMONAS AERUGINOSA

1966 ◽  
Vol 12 (5) ◽  
pp. 1015-1022 ◽  
Author(s):  
Margaret von Tigerstrom ◽  
J. J. R. Campbell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glucose Oxidation ◽  
Nadh Oxidase ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Succinic Dehydrogenase ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
The Glyoxylate Cycle

The enzymes of the glyoxylate cycle, the tricarboxylic acid cycle, glucose oxidation, and hydrogen transport were measured in extracts of Pseudomonas aeruginosa grown with glucose, α-ketoglutarate, or acetate as sole carbon source. The specific activity of isocitritase was increased 25-fold by growth on acetate whereas malate synthetase was increased only 4-fold. All of the enzymes of glucose metabolism, operative at the hexose level, were inducible. The enzymes of the tricarboxylic acid cycle were present under all conditions of growth but extracts from acetate-grown cells contained only one-quarter of the fumarase and pyruvic oxidase activity and half the malate-oxidizing activity of the other extracts. Transhydrogenase, NADH oxidase, and NADPH oxidase activities were similar in each type of extracts. Most of the enzymes were present in the soluble cytoplasm, exceptions being glucose oxidase, succinic dehydrogenase, and NADH oxidase.

Effect of Leaf Senescence on Glyoxylate Cycle Enzyme Activities

1992 ◽  
Vol 19 (6) ◽  
pp. 723 ◽  
Author(s):  
L Pistelli ◽  
P Perata ◽  
A Alpi
Keyword(s):  
Malate Dehydrogenase ◽  
Enzyme Activities ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Malate Synthase ◽  
Cycle Enzyme ◽  
Hydroxypyruvate Reductase ◽  
Foliar Senescence ◽  
The Glyoxylate Cycle

In order to elucidate the metabolism of the peroxisomes during foliar senescence of leaf beet (Beta vulgaris L., var. cicla), peroxisomal activities have been determined at various stages of senescence. Catalase and hydroxypyruvate reductase activities decreased whereas those of the β-oxidation pathway and glyoxylate cycle enzymes increased at the same time. The increased activities of malate synthase, isocitrate lyase, malate dehydrogenase and citrate synthase indicate that the glyoxylate cycle might be activated during the foliar senescence of leaf beet.

scholarly journals A Transcriptional Switch in the Expression of Yeast Tricarboxylic Acid Cycle Genes in Response to a Reduction or Loss of Respiratory Function

1999 ◽  
Vol 19 (10) ◽  
pp. 6720-6728 ◽  
Author(s):  
Zhengchang Liu ◽  
Ronald A. Butow
Keyword(s):  
Binding Site ◽  
Respiratory Function ◽  
Leucine Zipper ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Helix Loop Helix ◽  
Expression Of Genes ◽  
The Glyoxylate Cycle

ABSTRACT The Hap2,3,4,5p transcription complex is required for expression of many mitochondrial proteins that function in electron transport and the tricarboxylic acid (TCA) cycle. We show that as the cells’ respiratory function is reduced or eliminated, the expression of four TCA cycle genes, CIT1, ACO1, IDH1, andIDH2, switches from HAP control to control by three genes, RTG1, RTG2, and RTG3. The expression of four additional TCA cycle genes downstream ofIDH1 and IDH2 is independent of theRTG genes. We have previously shown that theRTG genes control the retrograde pathway, defined as a change in the expression of a subset of nuclear genes, e.g., the glyoxylate cycle CIT2 gene, in response to changes in the functional state of mitochondria. We show that thecis-acting sequence controlling RTG-dependent expression of CIT1 includes an R box element, GTCAC, located 70 bp upstream of the Hap2,3,4,5p binding site in theCIT1 upstream activation sequence. The R box is a binding site for Rtg1p-Rtg3p, a heterodimeric, basic helix-loop-helix/leucine zipper transcription factor complex. We propose that in cells with compromised mitochondrial function, the RTG genes take control of the expression of genes leading to the synthesis of α-ketoglutarate to ensure that sufficient glutamate is available for biosynthetic processes and that increased flux of the glyoxylate cycle, via elevated CIT2 expression, provides a supply of metabolites entering the TCA cycle sufficient to support anabolic pathways. Glutamate is a potent repressor of RTG-dependent expression of genes encoding both mitochondrial and nonmitochondrial proteins, suggesting that it is a specific feedback regulator of the RTG system.

The possible role of some enzymes in sclerotia formation in Aspergillus ochraceus

1983 ◽  
Vol 29 (6) ◽  
pp. 718-723 ◽  
Author(s):  
Nachman Paster ◽  
Ilan Chet
Keyword(s):  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Pentose Phosphate ◽  
Aspergillus Ochraceus ◽  
Phosphogluconate Dehydrogenase ◽  
Cycle Plays ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
The Glyoxylate Cycle

The role of some enzymes in sclerotia production by Aspergillus ochraceus was studied using a sclerotia-producing strain grown under conditions in which sclerotia production was either favoured or inhibited. In addition, a mutant strain incapable of producing sclerotia was used. No significant differences in patterns of soluble proteins, polyphenol oxidase, and esterases could be detected electrophoretically by gel electrophoresis, while the peroxidase pattern of both the sclerotia-producing strain and the mutant showed three bands as compared with two bands that appeared when sclerotia formation was inhibited. The activities of the tricarboxylic acid cycle enzymes, malate dehydrogenase and succinate dehydrogenase, and those of the pentose-phosphate pathway, glucose-6 phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, were almost identical in sclerotia- and nonsclerotia-producing mycelia. The activities of isocitrate lyase and malate synthetase, key enzymes of the glyoxylate cycle, and that of glyoxylate dehydrogenase which is related to this cycle were significantly reduced when sclerotia formation was inhibited either by methionine or by high levels of CO2. It is suggested that the glyoxylate cycle plays an important role in sclerotia formation in the fungus.

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