Acetate metabolism in bovine ketosis

1959 ◽  
Vol 14 (6) ◽  
pp. 1029-1032 ◽  
Author(s):  
D. S. Kronfeld ◽  
Max Kleiber ◽  
J. M. Lucas
Keyword(s):  
Carbon Dioxide ◽  
Plasma Glucose ◽  
Milk Fat ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acetate Metabolism ◽  
Acid Cycle ◽  
The Mean ◽  
Fat Synthesis

The metabolism of intravenously injected acetate–1–C14 was compared in normal and ketotic cows. The mean standardized specific activity of milk citrate, casein, lactose, plasma glucose, respired carbon dioxide and urine acetone was greater in the ketotic than in the normal cows, while that of milk fat was markedly decreased. The total–C14 recovered in the milk fat within 48 hours was about 14% of the injected dose in the normal cows, but only about 3% in the ketotic cows. These results suggest that the proportion of acetate metabolized via the tricarboxylic acid cycle is increased, while milk fat synthesis from acetate is impaired during bovine ketosis. Submitted on December 15, 1958

STUDIES ON WHEAT PLANTS USING C14 COMPOUNDS: V. GERMINATION STUDIES WITH LABELLED WHEAT SEEDS

1957 ◽  
Vol 35 (1) ◽  
pp. 1259-1266 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Active Compound ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Carbon 14 ◽  
Wheat Seeds

Radioactive wheat seeds, obtained by injecting acetate-C14 into the stems of the parent plants, were germinated in the absence of light and nutrient and the fate of the carbon-14 was observed. Carbon respired as carbon dioxide had a higher specific activity than any of the major seed components except protein. Variations were found in the patterns by which material was transferred from the kernel to new tissue as reflected in a comparison of the activity of various components. Glutamic acid was the most active compound isolated either from the original seeds or from the new tissues. This observation, together with similarities noted in the intramolecular distribution of carbon-14 in glutamic acid of new tissue and seed residues, indicated that glutamic acid was reutilized for the biosynthesis of seedling protein. Changes in the labelling of glutamic acid during transfer to new tissue are qualitatively in accord with the idea that at least some of the amino acid is used after re-entry into the tricarboxylic acid cycle.

STUDIES ON WHEAT PLANTS USING C14 COMPOUNDS: V. GERMINATION STUDIES WITH LABELLED WHEAT SEEDS

1957 ◽  
Vol 35 (12) ◽  
pp. 1259-1266 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Active Compound ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Carbon 14 ◽  
Wheat Seeds

Radioactive wheat seeds, obtained by injecting acetate-C14 into the stems of the parent plants, were germinated in the absence of light and nutrient and the fate of the carbon-14 was observed. Carbon respired as carbon dioxide had a higher specific activity than any of the major seed components except protein. Variations were found in the patterns by which material was transferred from the kernel to new tissue as reflected in a comparison of the activity of various components. Glutamic acid was the most active compound isolated either from the original seeds or from the new tissues. This observation, together with similarities noted in the intramolecular distribution of carbon-14 in glutamic acid of new tissue and seed residues, indicated that glutamic acid was reutilized for the biosynthesis of seedling protein. Changes in the labelling of glutamic acid during transfer to new tissue are qualitatively in accord with the idea that at least some of the amino acid is used after re-entry into the tricarboxylic acid cycle.

scholarly journals Effects of sevoflurane anesthesia and abdominal surgery on the systemic metabolome: a prospective observational study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yiyong Wei ◽  
Donghang Zhang ◽  
Jin Liu ◽  
Mengchan Ou ◽  
Peng Liang ◽  
...  
Keyword(s):  
Abdominal Surgery ◽  
General Anesthesia ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Metabolic Changes ◽  
Sevoflurane Anesthesia ◽  
Glutamate Metabolism ◽  
Acid Cycle ◽  
Link Type ◽  
The Mean

Abstract Background Metabolic status can be impacted by general anesthesia and surgery. However, the exact effects of general anesthesia and surgery on systemic metabolome remain unclear, which might contribute to postoperative outcomes. Methods Five hundred patients who underwent abdominal surgery were included. General anesthesia was mainly maintained with sevoflurane. The end-tidal sevoflurane concentration (ETsevo) was adjusted to maintain BIS (Bispectral index) value between 40 and 60. The mean ETsevo from 20 min after endotracheal intubation to 2 h after the beginning of surgery was calculated for each patient. The patients were further divided into low ETsevo group (mean − SD) and high ETsevo group (mean + SD) to investigate the possible metabolic changes relevant to the amount of sevoflurane exposure. Results The mean ETsevo of the 500 patients was 1.60% ± 0.34%. Patients with low ETsevo (n = 55) and high ETsevo (n = 59) were selected for metabolomic analysis (1.06% ± 0.13% vs. 2.17% ± 0.16%, P < 0.001). Sevoflurane and abdominal surgery disturbed the tricarboxylic acid cycle as identified by increased citrate and cis-aconitate levels and impacted glycometabolism as identified by increased sucrose and D-glucose levels in these 114 patients. Glutamate metabolism was also impacted by sevoflurane and abdominal surgery in all the patients. In the patients with high ETsevo, levels of L-glutamine, pyroglutamic acid, sphinganine and L-selenocysteine after sevoflurane anesthesia and abdominal surgery were significantly higher than those of the patients with low ETsevo, suggesting that these metabolic changes might be relevant to the amount of sevoflurane exposure. Conclusions Sevoflurane anesthesia and abdominal surgery can impact principal metabolic pathways in clinical patients including tricarboxylic acid cycle, glycometabolism and glutamate metabolism. This study may provide a resource data for future studies about metabolism relevant to general anaesthesia and surgeries. Trial registration www.chictr.org.cn. identifier: ChiCTR1800014327.

Stable isotope determination of plasma lactate conversion into glucose in fasting infants

1995 ◽  
Vol 268 (4) ◽  
pp. E652-E659 ◽  
Author(s):  
P. F. Bougneres ◽  
F. Rocchiccioli ◽  
N. Nurjhan ◽  
J. Zeller
Keyword(s):  
Plasma Glucose ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Gas Chromatography Mass Spectrometry ◽  
Plasma Lactate ◽  
Acid Cycle ◽  
Reverse Conversion ◽  
Additional Group ◽  
Glucose Molecule ◽  
Fasting Duration

To quantify lactate gluconeogenesis, we developed a gas chromatography-mass spectrometry method based on the infusion of [6,6-2H2]glucose and [3-13C]lactate tracers to 12 infants aged 1-25 mo fasting for 11.5 +/- 1.5 h. Both rates of appearance of plasma glucose (26.7 +/- 2.6 mumol.kg-1.min-1, 4.8 +/- 0.5 mg.kg-1.min-1) and lactate (30.8 +/- 3.1 mumol.kg-1.min-1, 2.8 +/- 0.3 mg.kg-1.min-1) were remarkably elevated compared with adult values. The interconversion of plasma lactate and glucose was determined by 1) measuring the incorporation of 13C from [3-13C]lactate into plasma glucose; 2) correcting for the metabolic exchange of carbon atoms in the tricarboxylic acid cycle. For this purpose, an additional group of six infants was infused with [3-13C]lactate, and the distribution of 13C at specific carbon positions in the glucose molecule was determined using relevant ions in the electron-impact mass spectrum of its 1,2,5,6-diisopropylidene-3-O-acetyl-alpha-furanosyl derivative; and 3) measuring the reverse conversion of glucose to lactate in five other infants infused with [1-13C]glucose. We found that 54 +/- 2% of glucose was derived from plasma lactate (14.4 +/- 1.3 mumol.kg-1.min-1, 2.6 +/- 0.2 mg.kg-1.min-1). Lactate and glucose rates of appearance were correlated (r = 0.58, P < 0.05) and decreased with fasting duration (r = 0.66, P < 0.02). The correction factor for carbon exchange in the tricarboxylic acid cycle was 1.14 +/- 0.11.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Enhancing Bioethanol Production by Deleting Phosphoenolpyruvate Synthase and ADP-Glucose Pyrophosphorylase, and Shunting Tricarboxylic Acid Cycle In Synechocystis Sp. PCC 6803

2021 ◽  
Author(s):  
E-Bin Gao ◽  
Penglin Ye ◽  
Haiyan Qiu ◽  
Junhua Wu ◽  
Huayou Chen
Keyword(s):  
Carbon Dioxide ◽  
Ethanol Production ◽  
Atmospheric Carbon Dioxide ◽  
Metabolic Flux ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Photosynthetic Production ◽  
Engineered Strain ◽  
Pcc 6803

Abstract Background: The outstanding ability of directly assimilating carbon dioxide and sunlight to produce biofuels and chemicals impels photosynthetic cyanobacteria to become attractive organisms for the solution to the global warming crises and the world energy growth. The cyanobacteria-based method for ethanol production has been increasingly regarded as alternatives to food biomass-based fermentation and traditional petroleum-based production. Therefore, we engineered the model cyanobacterium Synechocystis sp. PCC 6803 to synthesize ethanol and optimized the biosynthetic pathways for improving ethanol production under photoautotrophic conditions.Results: In this study, we successfully achieved the photosynthetic production of ethanol from atmospheric carbon dioxide by an engineered mutant Synechocystis sp. PCC 6803 with over-expressing the heterologous genes encoding Zymomonas mobilis pyruvate decarboxylase (PDC) and Escherichia coli NADPH-dependent alcohol dehydrogenase (YqhD). The engineered strain was further optimized by an alternative engineering approach to improve cell growth, and increase the intracellular supply of the precursor pyruvate for ethanol production under photoautotrophic conditions. This approach includes blocking phosphoenolpyruvate synthetic pathway from pyruvate, removing glycogen storage, and shunting carbon metabolic flux of tricarboxylic acid cycle. Through redirecting and optimizing the metabolic carbon flux of Synechocystis, a high ethanol-producing efficiency was achieved (248 mg L-1 day-1) under photoautotrophic conditions with atmospheric CO2 as the sole carbon source. Conclusions: The engineered strain SYN009 (∆slr0301/pdc-yqhD, ∆slr1176/maeB) would become a valuable biosystem for photosynthetic production of ethanol and for expanding our knowledge of exploiting cyanobacteria to produce value chemicals directly from atmospheric CO2.

AN ANOMALOUS TRICARBOXYLIC ACID CYCLE IN ACETOBACTER MELANOGENUM

1960 ◽  
Vol 38 (3) ◽  
pp. 193-203 ◽  
Author(s):  
D. H. Bone ◽  
R. M. Hochster
Keyword(s):  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Oxidase System ◽  
Isocitric Dehydrogenase ◽  
Highly Active ◽  
Carbon Compounds ◽  
Condensing Enzyme

Extracts of gluconate-grown Acetobacter melanogenum contain condensing enzyme and DPN-isocitric dehydrogenase of low specific activity. No evidence could be found for the presence of phosphotransacetylase, aconitase, or TPN-isocitric dehydrogenase. Since the organism or its extracts cannot synthesize the necessary four carbon compounds from pyruvate and from acetate, it is concluded that the tricarboxylic acid cycle does not function in extracts of this organism in the usually accepted manner.The pyruvic oxidase system was found to be highly active, acetaldehyde being the chief intermediate and acetate the end product. The mechanism for the slow incorporation of acetate into other cell constituents is, at present, unknown.

METABOLISM OF C14 AMINO ACIDS AND AMIDES IN DETACHED LEAVES

1956 ◽  
Vol 34 (4) ◽  
pp. 423-433 ◽  
Author(s):  
C. D. Nelson ◽  
G. Krotkov
Keyword(s):  
Amino Acids ◽  
Double Bond ◽  
Glutamic Acid ◽  
Broad Bean ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Activity Data ◽  
Acid Cycle ◽  
Bean Leaves

Detached broad bean leaves were placed with their petioles in 0.01 M ammonium nitrate and allowed to carry on photosynthesis in C14O2 for various periods from 12 to 125 min. The radioactivities of the various amino acids formed from C14O2 were determined. In addition, these amino acids were degraded by decarboxylation with ninhydrin. From the specific activity data it was concluded that the amino acid closest to the site of carbon dioxide fixation in photosynthesis was alanine, followed by aspartic and glutamic acids, with the amides farthest removed. From the intramolecular distribution of label it was concluded that asparagine and glutamine were formed from their corresponding amino acids. The labelling in aspartic and glutamic acids was not consistent with the view that these two amino acids are formed from their corresponding α-keto acids produced by operation of the conventional tricarboxylic acid cycle. A C2 plus C2 condensation is postulated for the formation of aspartic acid. A shift in the double bond in the aconitase reaction of the tricarboxylic acid cycle would account for the observed labelling in glutamic acid. When acetate-1-C14 was fed to detached broad bean leaves in the light or dark, the distribution of label in glutamic acid supported the suggestion that there is such a. shift in the double bond in the aconitase reaction. Sodium arsenite, infiltrated into tobacco leaves, inhibited the biosynthesis of asparagine but not that of glutamine.

Structure, Carbon Dioxide Fixation and Metabolism of Stomata

1974 ◽  
Vol 1 (2) ◽  
pp. 221 ◽  
Author(s):  
CJ Pearson ◽  
FL Milthorpe
Keyword(s):  
Carbon Dioxide ◽  
Organic Acid ◽  
Co2 Fixation ◽  
Tricarboxylic Acid Cycle ◽  
Guard Cells ◽  
Tricarboxylic Acid ◽  
Light Illumination ◽  
Acid Cycle ◽  
Free Air ◽  
Positive Correlations

Studies were made of the structure and rates of CO2 fixation of epidermis and of changes in organic metabolites in Commelina cyanea during transition to light and dark in both normal and CO2-free air. Guard cells of C. cyanea and Vicia faba contain numerous highly developed mitochondria and starch-forming chloroplasts (mitochondria: chloroplast ratios of 3 : 1) in comparison to other epidermal cells with few mitochondria and rudimentary plastids without starch. Their rates of photosynthesis per chloroplast appeared to be at least as high as those of the mesophyll, but circumstantial evidence suggested that about half of current photosynthate was respired. The rate of CO2 fixation in the dark was about 0.2–0.4% of that in the light. Illumination caused an increase, and darkening a decrease, of aperture, malate, and organic acid 1% within the epidermis of C. cyanea. Darkening in CO2-free air was accompanied by only slight decreases in aperture and malate. There were close positive correlations between aperture and concentration of malate and between aperture and organic acid 14C. During opening, the rise in organic acid 14C was associated with a decline in amino acid 14C. It is suggested that organic acids may be formed through aspartate and possibly also from sugars and other amino acids entering the tricarboxylic acid cycle. Concentrations of sugars were not related to aperture although they increased on illumination and declined about 2 h after darkening. Polysaccharide concentrations in the epidermis of darkened leaves were similar to those in illuminated leaves.

Sign in / Sign up

Export Citation Format

Share Document