Metabolism of glucose-14C, pyruvate-14C, and mannitol-14C by Melampsora lini. I. Uptake

1968 ◽  
Vol 46 (4) ◽  
pp. 435-440 ◽  
Author(s):  
P. G. Williams ◽  
Michael Shaw
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Rust Fungus ◽  
Aerial Mycelium ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Mean Value ◽  
Pentose Phosphate ◽  
Endogenous Respiration ◽  
Melampsora Lini ◽  
Pentose Phosphate Pathways

Aerial mycelium of the flax rust fungus (Melampsora lini (Pers.) Lév.) was grown on infected flax cotyledons in tissue culture. The endogenous respiration of detached mycelium varied from 1.5 to 4.8 μl/h per milligram dry weight, with a mean value of 2.6 ± 1.0. There was a significant negative correlation between respiration rate and percentage dry weight (r = −0.832; P < 0.025). The respiration of mycelium stored for longer than 10 h after excision was stimulated by the addition of glucose; such stimulation was not obtained consistently with freshly collected mycelium.The production of 14CO2 and the disappearance of radioactivity from the medium were measured at intervals during incubation of mycelium with glucose-1- and -6-14C, sodium pyruvate-1-, -2-, and -3-14C and mannitol-1-6-14C. Evidence was obtained that glucose is oxidized in the Embden–Meyerhof and pentose phosphate pathways and that pyruvate is oxidized via acetyl CoA and the tricarboxylic acid cycle. Rapid utilization of pyruvate- and mannitol-14C was preceded by a lag period of 4 to 9 h. The results are discussed in relation to the suitability of aerial mycelium for the study of rust metabolism.

Metabolism of glucose-14C, pyruvate-14C, and mannitol-14C by Melampsora lini. II. Conversion to soluble products

1968 ◽  
Vol 46 (4) ◽  
pp. 453-460 ◽  
Author(s):  
D. Mitchell ◽  
Michael Shaw
Keyword(s):  
Pentose Phosphate Pathway ◽  
Tricarboxylic Acid Cycle ◽  
Rust Fungus ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Soluble Carbohydrates ◽  
Melampsora Lini ◽  
Carbohydrate Fraction ◽  
The Tca Cycle

Mycelium of the flax rust fungus (Melampsora lini (Pers.) Lév.), grown on flax cotyledons in tissue culture, had a mean [Formula: see text]of 4.1 and a mean C6/C1 ratio of 0.14, measured after 4 hours in radioactive glucose. The C6/C1 ratio increased with time and also after treatment with 10−5 M 2,4-dinitrophenol. The relative labelling of the (80%) ethanol-soluble carbohydrates, and organic and amino acid fractions after incubation with glucose-1-, -2-, or -6-14C also indicated preferential release of C1 as 14CO2. Trehalose (unknown A) was tentatively identified in the carbohydrate fraction and was mildly radioactive after incubation of the mycelium with labelled glucose for 3 hours. The principal radioactive products of glucose in this fraction were two unknowns, B and C, which were tentatively identified as mannitol and arabitol. The labelling patterns were consistent with their formation from intermediates of the pentose phosphate pathway. The distribution of radioactivity derived from glucose in alanine, glutamate, and aspartate also indicated that hexose or triose units formed in the pentose phosphate pathway were converted to pyruvate, which either gave rise to alanine or was further oxidized in the tricarboxylic acid cycle. Incubation with pyruvate-1-, -2-, or -3-14C for 3 hours gave rise to 14CO2 and labelled alanine, glutamate, and aspartate in a manner consistent with the operation of the TCA cycle. Mannitol-1-6-14C was not metabolized to any appreciable extent in this period, but did give rise to 14CO2 and to several unidentified compounds in the carbohydrate fraction.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: III. THE PATTERN OF RESPIRATION IN RUSTED AND MILDEWED CEREAL LEAVES

1957 ◽  
Vol 35 (3) ◽  
pp. 389-407 ◽  
Author(s):  
Michael Shaw ◽  
D. J. Samborski
Keyword(s):  
Oxygen Uptake ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Pentose Phosphate ◽  
Host Tissue ◽  
Infected Tissue ◽  
Short Term ◽  
Pasteur Effect ◽  
Host Parasite ◽  
Leaf Disks

The first leaves of resistant (Khapli) and susceptible (Little Club) species of wheat were heavily inoculated with stem rust (Race 15B). After infection, oxygen consumption per unit dry weight increased two- to three-fold and then fell off again. The R.Q. remained close to 1.0 until the respiratory peak was reached and then declined to 0.80 to 0.85, at least in Khapli. The INR/OR values (approximately 1.2) suggest the operation of a Pasteur effect in uninfected tissue. With infected tissue there was little or no increase in NR as oxygen uptake rose and the INR/OR values declined steadily to about 0.2 to 0.3. The oxygen uptake of rusted, mildewed, and uninfected tissue was stimulated by 2,4-dinitrophenol. The percentage stimulation was reduced by infection. The smallest percentage stimulations were observed, after the respiratory peak had been passed, with infected tissue of Khapli, in which chlorosis and other degenerative changes developed quickly. The actual increases in oxygen uptake obtained with 10−5 M dinitrophenol were about the same for infected as for uninfected tissue, but, in Khapli, fell sharply after the respiratory maximum. Leaf-disks were incubated separately with glucose-1-C14, glucose-6-C14, and glucose-UL-C14, and the relative activities of the carbon dioxide produced were measured. The C6/C1 ratio showed a significant negative correlation with the oxygen uptake of rusted tissue, suggesting that the pentose phosphate pathway is of increased importance in infected tissue. The C6/C1 ratio was also reduced in the host tissue at the loci of mildew infections. In short term experiments dinitrophenol raised the C6/C1 ratio. The significance of the results is discussed and it is concluded that infection with rust or mildew not only raises the respiration rate but alters the pathway of respiration in the host tissue.

scholarly journals Complete Genome Sequence of the Marine, Chemolithoautotrophic, Ammonia-Oxidizing Bacterium Nitrosococcus oceani ATCC 19707

2006 ◽  
Vol 72 (9) ◽  
pp. 6299-6315 ◽  
Author(s):  
Martin G. Klotz ◽  
Daniel J. Arp ◽  
Patrick S. G. Chain ◽  
Amal F. El-Sheikh ◽  
Loren J. Hauser ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Reducing Power ◽  
Pentose Phosphate ◽  
Type I ◽  
Circular Chromosome ◽  
Bisphosphate Carboxylase ◽  
Terminal Electron Acceptor ◽  
Genes Encoding ◽  
Pentose Phosphate Pathways ◽  
Ammonia Oxidizing Bacterium

ABSTRACT The gammaproteobacterium Nitrosococcus oceani (ATCC 19707) is a gram-negative obligate chemolithoautotroph capable of extracting energy and reducing power from the oxidation of ammonia to nitrite. Sequencing and annotation of the genome revealed a single circular chromosome (3,481,691 bp; G+C content of 50.4%) and a plasmid (40,420 bp) that contain 3,052 and 41 candidate protein-encoding genes, respectively. The genes encoding proteins necessary for the function of known modes of lithotrophy and autotrophy were identified. Contrary to betaproteobacterial nitrifier genomes, the N. oceani genome contained two complete rrn operons. In contrast, only one copy of the genes needed to synthesize functional ammonia monooxygenase and hydroxylamine oxidoreductase, as well as the proteins that relay the extracted electrons to a terminal electron acceptor, were identified. The N. oceani genome contained genes for 13 complete two-component systems. The genome also contained all the genes needed to reconstruct complete central pathways, the tricarboxylic acid cycle, and the Embden-Meyerhof-Parnass and pentose phosphate pathways. The N. oceani genome contains the genes required to store and utilize energy from glycogen inclusion bodies and sucrose. Polyphosphate and pyrophosphate appear to be integrated in this bacterium's energy metabolism, stress tolerance, and ability to assimilate carbon via gluconeogenesis. One set of genes for type I ribulose-1,5-bisphosphate carboxylase/oxygenase was identified, while genes necessary for methanotrophy and for carboxysome formation were not identified. The N. oceani genome contains two copies each of the genes or operons necessary to assemble functional complexes I and IV as well as ATP synthase (one H+-dependent F0F1 type, one Na+-dependent V type).

Carbohydrate metabolism in the Plasmodium of the myxomycete Physarum flavicomum

1973 ◽  
Vol 19 (7) ◽  
pp. 803-810 ◽  
Author(s):  
Thomas J. Lynch ◽  
Henry R. Henney Jr.
Keyword(s):  
Carbohydrate Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Inorganic Nitrogen ◽  
Adenosine Monophosphate ◽  
Pentose Phosphate ◽  
Inorganic Nitrogen Source ◽  
Defined Media ◽  
Pentose Phosphate Pathways ◽  
Citrate Phosphate ◽  
Stimulation Of

Carbohydrate metabolism in the growing plasmodial phase of Physarum flavicomum was studied in partially defined media using the radiorespirometric technique and specifically labeled 14C-substrates. The Embden–Meyerhof–Parnas (EMP) – tricarboxylic acid cycle (TCA) and the pentose phosphate pathways are the routes by which glucose is used by this myxomycete. The replacement of the usual citrate–phosphate buffer by succinate–phosphate results in a decreased uptake of 14C-glucose from the medium and a corresponding decline in the rate of interval 14CO2 evolution. The addition of an inorganic nitrogen source (ammonium nitrate) to the medium also decreases the rate of carbohydrate metabolism and alters the relative participation of the pathways by favoring the EMP–TCA. Supplementing the medium with cyclic-3′-5′-adenosine monophosphate produces a transient stimulation of the rate of metabolism by the EMP–TCA. The Plasmodium is relatively impermeable to gluconate and pyruvate and does not readily metabolize amino acids.

scholarly journals Malonyl-proteome profiles of Staphylococcus aureus reveal lysine malonylation modification in enzymes involved in energy metabolism

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yanan Shi ◽  
Jingjing Zhu ◽  
Yan Xu ◽  
Xiaozhao Tang ◽  
Zushun Yang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Energy Metabolism ◽  
Active Sites ◽  
Current Knowledge ◽  
Tricarboxylic Acid Cycle ◽  
Protein A ◽  
Pentose Phosphate ◽  
Post Translational Modification ◽  
Bacterial Physiology ◽  
Dihydrolipoyl Dehydrogenase

Abstract Background Protein lysine malonylation, a novel post-translational modification (PTM), has been recently linked with energy metabolism in bacteria. Staphylococcus aureus is the third most important foodborne pathogen worldwide. Nonetheless, substrates and biological roles of malonylation are still poorly understood in this pathogen. Results Using anti-malonyl-lysine antibody enrichment and high-resolution LC-MS/MS analysis, 440 lysine-malonylated sites were identified in 281 proteins of S. aureus strain. The frequency of valine in position − 1 and alanine at + 2 and + 4 positions was high. KEGG pathway analysis showed that six categories were highly enriched, including ribosome, glycolysis/gluconeogenesis, pentose phosphate pathway (PPP), tricarboxylic acid cycle (TCA), valine, leucine, isoleucine degradation, and aminoacyl-tRNA biosynthesis. In total, 31 malonylated sites in S. aureus shared homology with lysine-malonylated sites previously identified in E. coli, indicating malonylated proteins are highly conserved among bacteria. Key rate-limiting enzymes in central carbon metabolic pathways were also found to be malonylated in S. aureus, namely pyruvate kinase (PYK), 6-phosphofructokinase, phosphoglycerate kinase, dihydrolipoyl dehydrogenase, and F1F0-ATP synthase. Notably, malonylation sites were found at or near protein active sites, including KH domain protein, thioredoxin, alanine dehydrogenase (ALD), dihydrolipoyl dehydrogenase (LpdA), pyruvate oxidase CidC, and catabolite control protein A (CcpA), thus suggesting that lysine malonylation may affect the activity of such enzymes. Conclusions Data presented herein expand the current knowledge on lysine malonylation in prokaryotes and indicate the potential roles of protein malonylation in bacterial physiology and metabolism.

scholarly journals Novel Antarctic yeast adapts to cold by switching energy metabolism and increasing small RNA synthesis

2021 ◽  
Author(s):  
D. Touchette ◽  
I. Altshuler ◽  
C. Gostinčar ◽  
P. Zalar ◽  
I. Raymond-Bouchard ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Phylogenetic Analyses ◽  
Regulation Of Gene Expression ◽  
Pentose Phosphate ◽  
Metabolic Switch ◽  
Antarctic Yeast ◽  
Fungal Adaptation ◽  
Pentose Phosphate Pathways ◽  
Post Transcriptional Regulation

AbstractThe novel extremophilic yeast Rhodotorula frigidialcoholis, formerly R. JG1b, was isolated from ice-cemented permafrost in University Valley (Antarctic), one of coldest and driest environments on Earth. Phenotypic and phylogenetic analyses classified R. frigidialcoholis as a novel species. To characterize its cold-adaptive strategies, we performed mRNA and sRNA transcriptomic analyses, phenotypic profiling, and assessed ethanol production at 0 and 23 °C. Downregulation of the ETC and citrate cycle genes, overexpression of fermentation and pentose phosphate pathways genes, growth without reduction of tetrazolium dye, and our discovery of ethanol production at 0 °C indicate that R. frigidialcoholis induces a metabolic switch from respiration to ethanol fermentation as adaptation in Antarctic permafrost. This is the first report of microbial ethanol fermentation utilized as the major energy pathway in response to cold and the coldest temperature reported for natural ethanol production. R. frigidialcoholis increased its diversity and abundance of sRNAs when grown at 0 versus 23 °C. This was consistent with increase in transcription of Dicer, a key protein for sRNA processing. Our results strongly imply that post-transcriptional regulation of gene expression and mRNA silencing may be a novel evolutionary fungal adaptation in the cryosphere.

scholarly journals Metabolome Shift in Both Metastatic Breast Cancer Cells and Astrocytes Which May Contribute to the Tumor Microenvironment

2021 ◽  
Vol 22 (14) ◽  
pp. 7430
Author(s):  
Hiromi Sato ◽  
Ayaka Shimizu ◽  
Toya Okawa ◽  
Miaki Uzu ◽  
Momoko Goto ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Metastatic Breast ◽  
Principal Component ◽  
Pentose Phosphate ◽  
Metastatic Brain Tumors ◽  
Pentose Phosphate Pathways ◽  
Culture Supernatants

The role of astrocytes in the periphery of metastatic brain tumors is unclear. Since astrocytes regulate central nervous metabolism, we hypothesized that changes in astrocytes induced by contact with cancer cells would appear in the metabolome of both cells and contribute to malignant transformation. Coculture of astrocytes with breast cancer cell supernatants altered glutamate (Glu)-centered arginine–proline metabolism. Similarly, the metabolome of cancer cells was also altered by astrocyte culture supernatants, and the changes were further amplified in astrocytes exposed to Glu. Inhibition of Glu uptake in astrocytes reduces the variability in cancer cells. Principal component analysis of the cancer cells revealed that all these changes were in the first principal component (PC1) axis, where the responsible metabolites were involved in the metabolism of the arginine–proline, pyrimidine, and pentose phosphate pathways. The contribution of these changes to the tumor microenvironment needs to be further pursued.

scholarly journals Metabolic phases during the development of granulation tissue

1967 ◽  
Vol 105 (1) ◽  
pp. 333-341 ◽  
Author(s):  
Kirsti Lampiaho ◽  
E. Kulonen
Keyword(s):  
Granulation Tissue ◽  
Collagen Synthesis ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Acid Cycle ◽  
Short Period ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Observation Period

1. The metabolism of incubated slices of sponge-induced granulation tissue, harvested 4–90 days after the implantation, was studied with special reference to the capacity of collagen synthesis and to the energy metabolism. Data are also given on the nucleic acid contents during the observation period. Three metabolic phases were evident. 2. The viability of the slices for the synthesis of collagen was studied in various conditions. Freezing and homogenization destroyed the capacity of the tissue to incorporate proline into collagen. 3. Consumption of oxygen reached the maximum at 30–40 days. There was evidence that the pentose phosphate cycle was important, especially during the phases of the proliferation and the involution. The formation of lactic acid was maximal at about 20 days. 4. The capacity to incorporate proline into collagen hydroxyproline in vitro was limited to a relatively short period at 10–30 days. 5. The synthesis of collagen was dependent on the supply of oxygen and glucose, which latter could be replaced in the incubation medium by other monosaccharides but not by the metabolites of glucose or tricarboxylic acid-cycle intermediates.

THE PHYSIOLOGY OF HOST-PARASITE RELATIONS: IX. FURTHER OBSERVATIONS ON THE ACCUMULATION OF RADIOACTIVE SUBSTANCES AT RUST INFECTIONS

1961 ◽  
Vol 39 (6) ◽  
pp. 1393-1407 ◽  
Author(s):  
Michael Shaw
Keyword(s):  
Specific Activity ◽  
Dry Weight ◽  
Insoluble Fraction ◽  
Pentose Phosphate ◽  
Accumulation Ratio ◽  
X Ray ◽  
Specific Activities ◽  
Leaf Segments ◽  
Wheat Leaves ◽  
Host Parasite

Wang (Can. J. Botany, 38, 635–642 (1960)) concluded that the accumulation of radioactivity observed on radioautographs at infection sites on rusted leaves fed with C14-labelled substances was 'apparent' rather than real. The ‘accumulation ratio’ is defined as the ratio of the specific activities (c.p.m./mg dry weight of intact tissue) of rust-infected to uninfected areas of infected leaves. Theoretical considerations relating to the radioautography of leaves labelled with C14 and to the measurement of ‘accumulation ratios’ by extraction of C14-labelled substances from rusted and uninfected segments of infected leaves, as well as experimental data, show that Wang's conclusion is not generally applicable.Experimentally, it was shown using polymethacrylate C14 sources that differences in distance between sources and X-ray film of the order of 100 μ had no effect on the intensity of autoradiographs. Rust-infected leaves, fed with radioactive glucose, were radiographed between X-ray plates. Localization of radioactivity at infection sites was observed on both ‘dorsal’ and ‘ventral’ radiographs, indicating a real accumulation per unit area. Ventral were more radioactive than dorsal surfaces. The main development of the fungus occurred on the former. Radioautography revealed that C14 from glucose-1-C14, glucose-6-C14, and uniformly labelled glucose fed to excised wheat leaves became localized at 10-day-old rust infections in 2 hours. ‘Accumulation ratios’ calculated from the specific activity of leaf segments remained close to 1.0 for at least 6 hours after introduction of the tracer, but increased to more than 2 after 24 hours. When ‘accumulation ratios’ were calculated from the specific activities of individual pustules (excised with a punch 1 mm in diameter) and interpustular disks, values greater than 1 were observed in 2 hours, thus confirming the results of autoradiography. Differences between the ‘accumulation ratios’ observed with glucose-6-C14 and glucose-1-C14 were consistent with an increased role of the pentose phosphate pathway at infection sites. Incorporation of C14 from uniformly labelled glucose into the alcohol-insoluble fraction of rusted leaf segments was 2.5-fold that in uninfected segments in 6 hours and 3.65-fold in 24 hours. The humin formed during hydrochloric acid hydrolysis accounted for approximately 50% of the activity of the alcohol-insoluble material. The ‘accumulation ratio’ for the alcohol-soluble material was only 1.56 after 24 hours.All the results support the view (Shaw and Samborski, Can. J. Botany, 34, 389–405 (1956)) that there is a quantitative, metabolically dependent accumulation of C14 from radioactive glucose at vigorous rust infections. The relative roles of fungus and host in this process are discussed briefly.

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