1,280 results on '"Carbon Dioxide biosynthesis"'
Search Results
102. Palmitic acid oxidation and incorporation into triglyceride by needle liver biopsy specimens from control subjects and patients with alcoholic fatty liver disease.
- Author
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Leung NW and Peters TJ
- Subjects
- Adult, Biopsy, Carbon Dioxide biosynthesis, Culture Techniques, Esterification, Female, Humans, Ketone Bodies biosynthesis, Male, Middle Aged, Oxidation-Reduction, Palmitic Acid, Fatty Liver, Alcoholic metabolism, Liver metabolism, Palmitic Acids metabolism, Triglycerides biosynthesis
- Abstract
A micro-technique was developed to measure fatty acid oxidation in vitro and to investigate its possible derangement in alcoholic fatty liver disease. Percutaneous liver biopsy specimens were obtained from nine control subjects and 28 alcoholic patients with mild to severe fatty liver. Fresh tissue (10-15 mg) was incubated at 37 degrees C for 90 min in a sealed reaction flask containing 1.92 mmol/l [1-14C]palmitic acid (1-2 microCi) and 1% essentially fatty acid free albumin in Krebs-Henseleit buffer, pH 7.4. Radiolabelled CO2 and perchloric acid-soluble ketone bodies were isolated and counted. CO2 production was markedly reduced in alcoholic patients with mild and severe fatty liver compared with controls. This depression was reversed by the addition of malate to the reaction flask but not by carnitine or coenzyme A. Ketone body production was similar in controls and patients with mild and severe fatty liver. After the incubation in vitro, the tissue was extracted with chloroform/methanol and the triglyceride fraction isolated by thin layer chromatography and counted for radioactivity. The rate of palmitic acid incorporation into triglyceride was higher in alcoholic patients, particularly those with severe fatty infiltration, compared with controls. It is suggested that alcoholic fatty liver is accompanied by a progressive reduction in palmitic acid oxidation with the major defect occurring in the tricarboxylic acid cycle. In contrast, the rate of palmitic acid esterification into triglyceride is enhanced.
- Published
- 1986
- Full Text
- View/download PDF
103. Experimental errors associated with the heterotrophic activity technique.
- Author
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Albright LJ and Wentworth JW
- Subjects
- Animals, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Glucose metabolism, Sulfuric Acids, Plankton metabolism, Water Microbiology
- Published
- 1976
104. Hypoxia induced preferential ketone utilization by rat brain slices.
- Author
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Kirsch JR and D'Alecy LG
- Subjects
- 3-Hydroxybutyric Acid, Animals, Carbon Dioxide biosynthesis, Glucose metabolism, Hydroxybutyrates metabolism, Hypoxia physiopathology, In Vitro Techniques, Lipids biosynthesis, Male, Rats, Brain metabolism, Hypoxia metabolism, Ketones metabolism
- Abstract
When exposed to hypoxia, intact mice, with elevated blood ketones, live longer than mice with normal blood ketones. To evaluate a possible mechanism responsible for this phenomenon a rat brain slice preparation was used to determine if brain tissue would utilize glucose or ketones preferentially during exposure to reduced oxygen. Reducing available oxygen in the incubation medium from 95%, in steps, to 5% produced the expected gradual reduction in the carbon dioxide formation from glucose. In contrast, reducing the oxygen level to 40 and 20% resulted in a statistically significant stimulation of the production of carbon dioxide from the ketone beta-hydroxybutyrate. At very low oxygen levels carbon dioxide production from either substrate was reduced. These results are consistent with the hypothesis that ketones can be used in addition to glucose as a substrate for brain energy production even during reduced oxygen availability. If the increase in carbon dioxide production from ketones can be equated with an increase in energy production from this supplemental substrate then ketones may be therapeutically useful in avoiding the collapse of brain function during moderate hypoxia.
- Published
- 1984
- Full Text
- View/download PDF
105. Fermentation of cellulose and cellobiose by Clostridium thermocellum in the absence of Methanobacterium thermoautotrophicum.
- Author
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Weimer PJ and Zeikus JG
- Subjects
- Acetates biosynthesis, Anaerobiosis, Bacteria enzymology, Butyrates metabolism, Carbon Dioxide biosynthesis, Cellulase metabolism, Clostridium enzymology, Ethanol metabolism, Fermentation, Hot Temperature, Hydrogen metabolism, Lactates biosynthesis, Methane biosynthesis, Bacteria metabolism, Cellulose metabolism, Clostridium metabolism, Disaccharides metabolism
- Abstract
The fermentation of cellulose and cellobiose by Clostridium thermocellum monocultures and C. thermocellum/Methanobacterium thermoautotrophicum cocultures was studied. All cultures were grown under anaerobic conditions in batch culture at 60 degrees C. When grown on cellulose, the coculture exhibited a shorter lag before initiation and growth and celluloysis than did the monoculture. Cellulase activity appeared earlier in the coculture than in the monoculture; however, after growth had ceased, cellulase activity was greater in the monoculture. Monocultures produced primarily ethanol, acetic acid, H2 and CO2. Cocultures produced more H2 and acetic acid and less ethanol than did the monoculture. In the coculture, conversion of H2 to methane was usually complete, and most of the methane produced was derived from CO2 reduction rather than from acetate conversion. Agents of fermentation stoppage were found to be low pH and high concentrations of ethanol in the monoculture and low pH in the coculture. Fermentation of cellobiose was more rapid than that of cellulose. In cellobiose medium, the methanogen caused only slight changes in the fermentation balance of the Clostridium, and free H2 was produced.
- Published
- 1977
- Full Text
- View/download PDF
106. The effect of serum from obese and normal weight men on glucose metabolism in leucocytes.
- Author
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Myking O, Kjøsen B, and Bassøe HH
- Subjects
- Adolescent, Adult, Aged, Carbon Dioxide biosynthesis, Humans, Lactates biosynthesis, Male, Middle Aged, Blood Glucose metabolism, Leukocytes metabolism, Obesity blood
- Abstract
The influence of pooled serum from either obese or normal weight males on glucose metabolism in human leucocytes has been studied. Leucocytes from normal weight males were incubated with 10-90% pooled serum and either [U-14C], or [1-14C]glucose. Compared to serum from the normal weight males, serum from the obese group had a more stimulating effect on the 14CO2 and [14C]lactate production from [U-14C]glucose and on the 14CO2 production from [1-14C]glucose. The two serum pools had the same stimulating effect on the Embden-Meyerhof pathway as indicated by the formation of [14C]lactate from [1-14C]glucose. Calculations revealed that the activity in the pentose phosphate pathway was stimulated more by serum from obese, than from normal weight males. It is a possibility that increased stimulation of the pentose phosphate pathway may contribute to the development of overweight.
- Published
- 1980
- Full Text
- View/download PDF
107. Bacterial decomposition of synthetic 14C-labeled lignin and lignin monomer derivatives.
- Author
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Gradziel K, Haider K, Kochmańska J, Malarczyk E, and Trojanowski J
- Subjects
- Anisoles metabolism, Benzoates metabolism, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Catechin metabolism, Catechols metabolism, Cinnamates metabolism, Culture Media, Finland, Isotope Labeling, Lignin analogs & derivatives, Methyl Ethers metabolism, Oxygen Consumption, Phenols metabolism, Vanillic Acid metabolism, Lignin metabolism, Nocardia metabolism, Soil Microbiology
- Abstract
Nocardia sp. which was isolated from soil is capable of degrading synthetic lignin and utilizing its monomer derivatives. Decomposition was monitored by measuring the 14CO2 evolved and O2 consumed, when the bacterium was grown on a medium containing specifically 14C-labeled ligning or monomer phenolic compounds as major carbon source. The time course of the 14CO2 release and O2 uptake indicates a significant depolymerization and utilization of lignin by the Nocardia sp.
- Published
- 1978
108. Metabolism of glucose by human embryos.
- Author
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Wales RG, Whittingham DG, Hardy K, and Craft IL
- Subjects
- Carbon metabolism, Carbon Dioxide biosynthesis, Humans, Lactates biosynthesis, Lactic Acid, Oocytes metabolism, Blastocyst metabolism, Glucose metabolism
- Abstract
Glucose turnover, as measured by CO2 production, lactate accumulation and carbon incorporation from [U-14C]glucose as sole energy substrate, was low on the 2nd day of culture of human embryos resulting from in-vitro fertilization but above that of unfertilized oocytes. In general, all parameters of metabolism increased substantially during the following 2 days of development but the rate of increase in lactate production was greater than that of CO2, especially between Days 3 and 4. Within developing embryos, no correlation was evident between the metabolic turnover of glucose and the method of patient stimulation, the morphological quality of embryos or the apparent rate of cleavage in culture. The results indicate that, before Day 3 of development, glucose is not effective as an energy source for the human embryo because of a blockade to glycolysis similar to that in mouse embryos.
- Published
- 1987
- Full Text
- View/download PDF
109. Effect of seminal prostaglandins on the metabolism of human spermatozoa.
- Author
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Kelly RW
- Subjects
- Carbon Dioxide biosynthesis, Humans, Lactates biosynthesis, Male, Prostaglandins E metabolism, Prostaglandins E pharmacology, Prostaglandins, Synthetic pharmacology, Semen metabolism, Spermatozoa drug effects, Prostaglandins E physiology, Semen physiology, Spermatozoa metabolism
- Abstract
Study of the effects of 19-hydroxy E prostaglandins on the metabolism of washed ejaculated human spermatozoa showed that these compounds depress the respiration of the spermatozoa, but do not affect the production of lactate. This effect is not seen with the prostaglandins of the E and F series.
- Published
- 1977
- Full Text
- View/download PDF
110. Carbon-monoxide oxidation in cell-free extracts of Clostridium pasteurianum.
- Author
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Thauer RK, Fuchs G, Käufer B, and Schnitker U
- Subjects
- Anaerobiosis, Carbon Dioxide biosynthesis, Catalysis, Cell-Free System, Chromatography, Gas, Cyanides, Electron Transport, Ferredoxins, Flavin Mononucleotide, Flavin-Adenine Dinucleotide, Hydrogen-Ion Concentration, Iodides, Kinetics, Light, NAD, NADP, Oxidation-Reduction, Temperature, Vitamin B 12, Carbon Monoxide metabolism, Clostridium metabolism
- Published
- 1974
- Full Text
- View/download PDF
111. Characterization of the growth of Pseudomonas putida LP on lipoate and its analogues: transport, oxidation, sulphur source, and enzyme induction.
- Author
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Shih JC, Rozo ML, Wright LD, and McCormick DB
- Subjects
- Acetates metabolism, Biological Transport, Active, Caprylates metabolism, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Cell-Free System, Chromatography, Coenzyme A Ligases metabolism, Enzyme Induction, Glucose metabolism, Isocitrates, Malates, Oxidation-Reduction, Oxo-Acid-Lyases, Oxygen Consumption, Pseudomonas enzymology, Pseudomonas growth & development, Spectrophotometry, Stereoisomerism, Sulfur metabolism, Thioctic Acid analysis, Pseudomonas metabolism, Thioctic Acid metabolism
- Abstract
Pseudomonas putida LP, which grows on lipoate, NH4NO3 and mineral salts, converts most of the organic substrate to bisnor-lipoate (1,2-dithiolane-3-propanoic acid) and acetyl-CoA. D-, L-, or DL-lipoate serve equally well as carbon and sulphur sources. There was no growth on or bacterial oxidation of the chemically synthesized bisnor- or tetranor-(1,2-dithiolane-3-carboxylic acid) chain-shortened analogues, but these, as well as lipoate, could supply the sulphur needed for growth when acetate was provided as the sole source of carbon. The uptake of lipoate by the bacterium is very slow and non-inducible, while the uptake of acetate is faster than octanoate. The oxidation of octanoate is more rapid and extensive than that of lipoate. Levels of acyl-CoA synthetase are not affected by the source of carbon, but activities of isocitrate lyase and malate synthase are higher when the cells are grown in acetate, octanoate or lipoate and lower when glucose is the carbon source. The glyoxylate cycle is induced to facilitate utilization of acetyl-CoA derived from lipoate, which is also degraded to water-soluble catabolites that yield the much smaller amount of sulphur required for growth.
- Published
- 1975
- Full Text
- View/download PDF
112. Iotrol, iodixanol, and 2-deoxy-D-glucose effects on neural tissue CO2 production.
- Author
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Morris TW, Ekholm SE, Prentice L, and Fonte D
- Subjects
- Animals, Dose-Response Relationship, Drug, Rats, Rats, Inbred Strains, Carbon Dioxide biosynthesis, Contrast Media pharmacology, Deoxy Sugars pharmacology, Deoxyglucose pharmacology, Hippocampus metabolism, Iodobenzoates pharmacology, Triiodobenzoic Acids pharmacology
- Abstract
In vivo and in vitro experiments have demonstrated that the myelographic agent metrizamide decreases neural tissue glucose metabolism whereas iohexol and iopamidol do not. This study compares the changes in slices of rat hippocampus CO2 production caused by the nonionic dimers iotrol and iodixanol with the effects of metrizamide and 2-deoxy-D-glucose. After 6-hr incubations, 70-mmol/l concentrations of iotrol and iodixanol increased CO2 production by 11 +/- 20% and 31 +/- 35%, respectively, as compared with the artificial CSF control medium. Metrizamide at 70 mmol/l and 2-deoxy-D-glucose at 35 mmol/l decreased CO2 production by 32 +/- 13% and 96 +/- 1%, respectively. The increases in CO2 production with iotrol and iodixanol appear to indicate that these molecules have some effect on cell metabolism. The mechanism for the increase in CO2 production could involve an effect on the glucose metabolic pathway or could be indirect via a mechanism that increases cell energy utilization. These in vitro effects have not been verified with in vivo experiments.
- Published
- 1989
113. [The role of the cell membrane transport in glucose repression of induceable enzyme synthesis].
- Author
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Höfer M, Seletzky-Hild O, and Dahle P
- Subjects
- Biological Transport, Active drug effects, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Cell Membrane metabolism, Cyclic AMP metabolism, Enzyme Induction, Enzyme Repression, Fructose pharmacology, Mitosporic Fungi enzymology, Stereoisomerism, Xylose metabolism, Xylose pharmacology, Enzymes biosynthesis, Glucose pharmacology, Mitosporic Fungi metabolism
- Published
- 1974
114. Evaluation of some biological tests as parameters for microbial activities in soils. I. Laboratory experiments.
- Author
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Abd-El-Malek Y, Monib M, Rizk SG, and Shehata M
- Subjects
- Bacteria enzymology, Bacteria growth & development, Carbon Dioxide biosynthesis, Cellulose metabolism, Evaluation Studies as Topic, Formazans metabolism, Glucose metabolism, Oxidoreductases metabolism, Soil, Triticum, Wood, Bacteria metabolism, Soil Microbiology
- Abstract
The experiments were confined to the effects of the addition of different sources of carbon (glucose, wheat straw, and sawdust) on the microbial activities in soils: loamy sand, loam and saline clay were used. The parameters used for this purpose were total bacterial counts, dehydrogenase test, CO2 evolution, and oxidation of organic carbon. Salinity of soils had deleterious effects on all the parameters used. Addition of organic matter resulted in marked increases in bacterial counts, formazan production, and CO2 evolution. Glucose showed the most rapid effect and highest levels. Wheat straw yielded the highest results and sawdust always showed the least effect.
- Published
- 1976
- Full Text
- View/download PDF
115. Energy expenditure by doubly labeled water: validation in humans and proposed calculation.
- Author
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Schoeller DA, Ravussin E, Schutz Y, Acheson KJ, Baertschi P, and Jéquier E
- Subjects
- Adult, Carbon Dioxide biosynthesis, Deuterium, Humans, Male, Mathematics, Oxygen Isotopes, Pulmonary Gas Exchange, Energy Metabolism, Water
- Abstract
To further validate the doubly labeled water method for measurement of CO2 production and energy expenditure in humans, we compared it with near-continuous respiratory gas exchange in nine healthy young adult males. Subjects were housed in a respiratory chamber for 4 days. Each received 2H2(18)O at either a low (n = 6) or a moderate (n = 3) isotope dose. Low and moderate doses produced initial 2H enrichments of 5 and 10 X 10(-3) atom percent excess, respectively, and initial 18O enrichments of 2 and 2.5 X 10(-2) atom percent excess, respectively. Total body water was calculated from isotope dilution in saliva collected at 4 and 5 h after the dose. CO2 production was calculated by the two-point method using the isotopic enrichments of urines collected just before each subject entered and left the chamber. Isotope enrichments relative to predose samples were measured by isotope ratio mass spectrometry. At low isotope dose, doubly labeled water overestimated average daily energy expenditure by 8 +/- 9% (SD) (range -7 to 22%). At moderate dose the difference was reduced to +4 +/- 5% (range 0-9%). The isotope elimination curves for 2H and 18O from serial urines collected from one of the subjects showed expected diurnal variations but were otherwise quite smooth. The overestimate may be due to approximations in the corrections for isotope fractionation and isotope dilution. An alternative approach to the corrections is presented that reduces the overestimate to 1%.
- Published
- 1986
- Full Text
- View/download PDF
116. Proceedings: Neetherlands Society for Microbiology meeting at Utrecht on 2 May 1973. Sporulation of anaerobic sporeformers.
- Author
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Anema PJ
- Subjects
- Ammonia biosynthesis, Anaerobiosis, Carbon Dioxide biosynthesis, Clostridium metabolism, Culture Media, Glucose metabolism, Hydrogen-Ion Concentration, Time Factors, Clostridium growth & development, Food Microbiology, Hot Temperature, Spores, Bacterial growth & development
- Published
- 1973
- Full Text
- View/download PDF
117. Comparison of methods to test chemicals for side effects on soil microorganisms.
- Author
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Zelles L, Scheunert I, and Korte F
- Subjects
- Carbon Dioxide biosynthesis, Ferrous Compounds analysis, Hot Temperature, Mercuric Chloride toxicity, Oxidation-Reduction, Pentachlorophenol toxicity, Soil Microbiology, Soil Pollutants toxicity
- Abstract
The effects of the test chemicals pentachlorophenol (PCP) and HgCl2 on the bioactivity of microorganisms in three different soils were studied in low and high concentrations (2 and 20 ppm). Bioactivity was measured in long-term experiments (18 weeks) by a threefold application of chemicals to soils of varying moisture content. The selected tests were measurements of ATP, of heat output under aerobic and anaerobic conditions and after amendment with glucose, of soil respiration after the addition of glucose, and Fe(III) reduction. The suitability of each test depends on soil microorganisms, on environmental conditions, and on soil properties. The effects caused by the chemicals were as follows. For the low concentration, stimulation or inhibition were mostly repaired within the observation period. The high concentration mostly induced inhibitions which increased or decreased as a consequence of the repeated application of the chemicals. The effects of chemicals were strongly modified by the soil types: in a soil with high organic matter content, differences to the control were lower than in soils with lower organic matter content. These experiments also indicate that measurement of only one physiological parameter is not sufficient to characterize chemicals ecotoxicologically.
- Published
- 1986
- Full Text
- View/download PDF
118. Inhibition of liver gluconeogenesis and CO2 production in both heart and liver by cyclopropane carboxylic acid in vitro.
- Author
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Bahl JJ, Shrago E, Brendel K, and Bressler R
- Subjects
- Animals, Carbon Dioxide biosynthesis, Carboxylic Acids pharmacology, In Vitro Techniques, Liver drug effects, Oxidation-Reduction drug effects, Rats, Cyclopropanes pharmacology, Gluconeogenesis drug effects, Liver metabolism, Myocardium metabolism
- Published
- 1978
119. The action of piracetam on 14C-glucose metabolism in normal and posthypoxic rat cerebral cortex slices.
- Author
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Domańska-Janik K and Zaleska M
- Subjects
- Animals, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Cerebral Cortex drug effects, Glycolysis drug effects, In Vitro Techniques, Oxygen Consumption drug effects, Rats, Stimulation, Chemical, Cerebral Cortex metabolism, Glucose metabolism, Oxygen pharmacology, Piracetam pharmacology, Pyrrolidinones pharmacology
- Abstract
The stimulating effect of piracetam on the respiration and glycolysis was observed in rat brain cortex slices incubated under oxygen atmosphere. After preincubation of the slices under pure nitrogen atmosphere, piracetam infuenced also decarboxylation of the C1-glucose carbon, indicating stimulation of the pentose cysle. Any significant effect of piracetam on the lowered by anoxia incorporation of 14C from U-14C-glucose into macromolecular fractions was not observed. The results have supported a protective effect of piracetam against oxygen deficiency, caused mainly by stimulation of metabolic glucose pathways, connected with energy production in CNS.
- Published
- 1977
120. Glucose, lactate, and palmitate as substrates for the resting cardiac myocyte.
- Author
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Piper HM, Spahr R, and Probst I
- Subjects
- Animals, Carbon Dioxide biosynthesis, Cell Separation, Cells, Cultured, Energy Metabolism, Female, Lactates biosynthesis, Lactic Acid, Myocardium metabolism, Rats, Rats, Inbred Strains, Time Factors, Glucose metabolism, Lactates metabolism, Myocardium cytology, Palmitates metabolism, Palmitic Acids metabolism
- Abstract
Cultured adult cardiac myocytes oxidize fatty acids and lactate preferentially to glucose. In contrast to other results obtained with isolated cardiac myocytes the preference for fatty acids is not dependent on carnitine administration, suggesting that the cells of this preparation possess sufficient reserves of carnitine and an intact mechanism for fatty acid activation. It is demonstrated by the substrate oxidation rates that these quiescent cells are in a state of minimal metabolic demand, thus resembling the arrested myocardium.
- Published
- 1985
121. Lipid metabolism during bacterial growth, sporulation, and germination: kinetics of fatty acid and macromolecular synthesis during spore germination and outgrowth of Bacillus thuringiensis.
- Author
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Nickerson KW, De Pinto J, and Bulla LA Jr
- Subjects
- Acetates metabolism, Bacillus growth & development, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Cell Division, Glutamates metabolism, Glycerol metabolism, Kinetics, Phenylalanine metabolism, Spores, Bacterial growth & development, Spores, Bacterial metabolism, Thymidine metabolism, Time Factors, Tritium, Uridine metabolism, Bacillus metabolism, Bacterial Proteins biosynthesis, DNA, Bacterial biosynthesis, Fatty Acids biosynthesis, Lipid Metabolism, RNA, Bacterial biosynthesis
- Abstract
The timing and kinetics of fatty acid synthesis are delineated for Bacillus thuringiensis spore germination and outgrowth by analyzing [U-14C]acetate and [2-3H]glycerol incorporation into chloroform-methanol-extractable and trichloroacetic acid-precipitable lipids. In addition to measurement of pulsed and continuous labeling of fatty acids, monitoring the incorporation of radioactive phenylalanine, thymidine, and uridine from the onset of germination through first cell division provides a profile of biochemical activities related to membrane differentiation and cellular development. Upon germination, ribonucleic acid synthesis is initiated, immediately followed by rapid and extensive fatty acid synthesis that in turn precedes protein, deoxyribonucleic acid and triglyceride synthesis. Significantly, formation of fatty acids from acetate exhibits further developmental periodicity in which a large transient increase in fatty acid synthetic activity coincides with the approach of cell division. Radiorespirometric analyses indicates only slight oxidative decarboxylation of acetate and corroborates the extreme involvement of acetate in specific fatty acid biosynthetic reactions throughout cellular modification. These findings graphically demonstrate an intimate association of fatty acid metabolism with commitment to spore outgrowth and subsequent cell division.
- Published
- 1975
- Full Text
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122. Effect of tolbutamide on the metabolism of Tetrahymena.
- Author
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Blum JJ, Connett RJ, and Porter P
- Subjects
- Acetates metabolism, Animals, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Glucose metabolism, Glycogen metabolism, Glyoxylates metabolism, Hexokinase metabolism, Oxidation-Reduction, Oxo-Acid-Lyases metabolism, Pyruvates metabolism, Succinate Dehydrogenase metabolism, Tetrahymena pyriformis drug effects, Tetrahymena pyriformis enzymology, Tetrahymena pyriformis growth & development, Tetrahymena pyriformis metabolism, Tolbutamide pharmacology
- Published
- 1974
- Full Text
- View/download PDF
123. Uncoupling and isotope effects in gamma-butyrobetaine hydroxylation.
- Author
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Holme E, Lindstedt S, and Nordin I
- Subjects
- Betaine metabolism, Carbon Dioxide biosynthesis, Carnitine biosynthesis, Humans, Kidney enzymology, Kinetics, Substrate Specificity, Tritium, gamma-Butyrobetaine Dioxygenase, Betaine analogs & derivatives, Mixed Function Oxygenases metabolism
- Abstract
Replacement of unlabeled gamma-butyrobetaine with gamma-[2,3,4-2H6]butyrobetaine has a profound effect on the stoichiometry between decarboxylation of 2-oxoglutarate and hydroxylation in the reaction catalyzed by human gamma-butyrobetaine hydroxylase. The ratios between decarboxylation and hydroxylation are 1.16 with unlabeled and 7.48 with deuterated gamma-butyrobetaine as substrate. From these ratios an internal isotope effect of 41 has been calculated. DV in the overall reaction measured as 2- oxoglutarate decarboxylation is 2.5 and DV/K is 1.0. For gamma-butyrobetaine hydroxylase from Pseudomonas sp. AK 1, 2-oxoglutarate decarboxylation exceeds hydroxylation with 10% when deuterated gamma-butyrobetaine is used. No excess was found with unlabeled substrate and no internal isotope effect could be calculated. DV for the bacterial enzyme is 6.
- Published
- 1984
- Full Text
- View/download PDF
124. Lipid and glycogen metabolism in the hypoxic heart: effects of epinephrine.
- Author
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Crass MF 3rd and Pieper GM
- Subjects
- Animals, Carbon Dioxide biosynthesis, Fatty Acids, Nonesterified metabolism, Glucose biosynthesis, Male, Oxidation-Reduction, Perfusion methods, Phospholipids metabolism, Rats, Triglycerides metabolism, Epinephrine pharmacology, Glycogen metabolism, Hypoxia metabolism, Lipid Metabolism, Myocardium metabolism
- Abstract
The metabolism of cardiac lipids and glycogen in hypoxic and well-oxygenated perfused rat hearts was studied in the presence or absence of epinephrine. Heart lipids were pre-labeled in vivo with [1-14C]palmitate. Triglyceride disappearance (measured chemically and radiochemically) was observed in well-oxygenated hearts and was stimulated by epinephrine (4.1 X 10(-7)M). Utilization of tissue triglycerides was inhibited in hypoxic hearts in the presence or absence of added epinephrine. Hypoxia resulted in a small increase in tissue 14C-free fatty acids and inhibition of 14C-labeled triglyceride fatty acid oxidation. Epinephrine had no stimulatory effect on fatty acid oxidation in hypoxic hearts. Utilization of 14C-labeled phospholipids (and total phospholipids) was similar in well-oxygenated and hypoxic hearts with or without added epinephrine. These results suggested that the antilipolytic effects of hypoxia were predominant over the lipolytic effects of epinephrine. Glycogenolysis was stimulated threefold by epinephrine in well-oxygenated hearts. Hypoxia alone was a potent stimulus to glycogenolysis. Addition of epinephrine to perfusates of hypoxic hearts resulted in a slight enhancement of glycogenolysis.
- Published
- 1975
- Full Text
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125. Effects of human and experimental cancer on the conversion of 14C tripalmitin to 14CO2.
- Author
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Costa G, Lyles K, and Ullrich L
- Subjects
- Animals, Carbon Dioxide biosynthesis, Female, Humans, Male, Mice, Oxygen Consumption, Carcinoma, Krebs 2 metabolism, Neoplasms metabolism, Palmitic Acids metabolism
- Abstract
14C Tripalmitin was administered intraperitoneally to control mice and to mice bearing subcutaneous Krebs-2 carcinoma. The rate of excretion of 14CO2 was studied. The presence of a tumor induced a greater than 80% suppression of the formation of 14CO2 within 24 hours from the implantation of the tumor, thus allowing unambiguous identification of the tumor-bearing mice. When cancer patients were studied, along with normal volunteers and patients with non-neoplastic diseases, 14CO2 excretion data could be used to identify the cancer patients with an overall accuracy of 84%.
- Published
- 1976
- Full Text
- View/download PDF
126. Ventilation and breathing patterns during hemodialysis-induced carbon dioxide unloading.
- Author
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De Backer WA, Heyrman RM, Wittesaele WM, Van Waeleghem JP, Vermeire PA, and De Broe ME
- Subjects
- Adult, Aged, Carbon Dioxide biosynthesis, Female, Humans, Hydrogen-Ion Concentration, Male, Middle Aged, Time Factors, Carbon Dioxide metabolism, Renal Dialysis, Respiration
- Abstract
Important CO2 unloading occurs during hemodialysis (HD) when acetate-buffered dialysate is used. This is accompanied by alveolar hypoventilation. To gain more insight into the mechanisms of this alveolar hypoventilation, breathing patterns were studied in 5 patients with end-stage renal failure during HD using acetate-buffered dialysate, which induces CO2 unloading, or bicarbonate without CO2 loss. Ventilation was continuously measured with calibrated respiratory inductance plethysmography using techniques of multiple linear regression analysis. At regular intervals, arterial blood gas was sampled and expired air was analyzed. Breathing patterns were analyzed for VE, VT, TI, TE, and VT/TI. All data were compared with the respective starting value and with the respective value in the other setup. A greater decrease in ventilation was seen during HD with an acetate-containing dialysate because of irregular breathing patterns that resulted in a prolongation of expiratory time. Important variations in tidal volumes, striking apnea periods, and occasional periodic breathing were observed. We suggest that these irregularities are due to CO2 unloading leading to the point where ventilation is totally mediated through the output of the peripheral chemoreceptors.
- Published
- 1987
- Full Text
- View/download PDF
127. Analysis of the determinants of renal cortical PCO2.
- Author
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Bidani A, Crandall ED, and DuBose TD Jr
- Subjects
- Absorption, Bicarbonates metabolism, Carbon Dioxide biosynthesis, Carbon Dioxide blood, Kidney Tubules, Proximal metabolism, Models, Biological, Partial Pressure, Carbon Dioxide metabolism, Kidney Cortex metabolism
- Abstract
Recent studies employing Pco2 microelectrodes demonstrated CO2 tensions in the renal cortex (60-65 mmHg) that are significantly greater than systemic arterial Pco2. Three sources for CO2 generation have been proposed: 1) luminal production from H+ and HCO-3,2) addition of HCO-3 to peritubular plasma with disequilibrium for H+/HCO-3/CO2, and 3) metabolic CO2 production. None of these mechanisms alone can adequately explain the findings. The purpose of this study was to examine mechanisms of elevated renal cortical Pco2 generation and maintenance by developing a mathematical model for the reaction and transport processes involved in proximal tubule HCO-3 reabsorption. Steady-state calculations of pH, Pco2, and [HCO-3] for luminal, cellular, and vascular compartments employing simple mass balance considerations are presented. Besides exploring the role of metabolic CO2 production in the genesis and maintenance of elevated renal cortical Pco2, we also propose and examine the additional mechanism of diffusive transfer of CO2 between renal cortical venular and afferent arteriolar capillaries. Our results show that the required magnitude of either metabolic CO2 production or diffusive CO2 transfer alone is large (3 mmol/liter RBF). However, vascular-vascular exchange of CO2 gas in combination with accepted levels of metabolic CO2 production can adequately explain the findings of an elevated renal cortical Pco2 of approximately 65 mmHg as measured experimentally in vivo.
- Published
- 1984
- Full Text
- View/download PDF
128. Energy requirements for the transport of methylthio-beta-D-galactoside by Escherichia coli: measurement by microcalorimetry and by rates of oxygen consumption and carbon dioxide production.
- Author
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Long RA, Martin WG, and Schneider H
- Subjects
- Biological Transport, Active drug effects, Buffers, Calorimetry, Glycerol pharmacology, Hot Temperature, Kinetics, Thiogalactosides pharmacology, Time Factors, Uncoupling Agents pharmacology, Carbon Dioxide biosynthesis, Energy Metabolism drug effects, Escherichia coli metabolism, Oxygen Consumption drug effects, Thiogalactosides metabolism, Thioglycosides metabolism
- Abstract
The energy cost for maintenance of gradients of methylthio-beta-d-galactoside in Escherichia coli was evaluated. Information was also obtained concerning the energy flow associated with gradient establishment under some circumstances. Energy flow was evaluated from transport-induced changes in the rate of heat evolution, oxygen consumption, and carbon dioxide production in metabolically active cells. Heats were measured with an isothermal calorimeter. Energy expenditure behavior was characterized by a transition that depended on the level of accumulation. The data for steady-state maintenance could be rationalized in terms of the Mitchell hypothesis, two models for influx and efflux, and a transition between them. At low levels of uptake, steady-state proton-methylthio-beta-d-galactoside (TMG) symport for influx and efflux occurred via a nonenergy-requiring exchange process. The only energy requirement was that necessary to pump back in any TMG exiting via a leakage pathway (model I). Above the transition, all influx occurred with proton symport, but all exit, leak and carrier mediated, occurred without proton symport (model II). The H(+)/TMG stoichiometric ratio computed for the region of model II applicability (carbon source present, high level of uptake) approached 1. This value agreed with that of other workers for downhill beta-galactoside flow, suggesting that the energy cost for both downhill and uphill flow was approximately the same. For low levels of uptake, initial establishment of the gradient was followed by a burst of metabolism that was much larger than that expected on the basis of the chemiosmotic hypothesis. In the absence of carbon source, the stimulation in respiration was sufficient to produce 13 times more protons than are apparently necessary to establish the gradient. The results indicate also that the nature of the biochemical process stimulated by TMG depends on its level of uptake. Insight into several aspects of the nature of these processes was provided through analysis of the heat, oxygen, and CO(2) data. The key factor controlling the transition in energy flow behavior is suggested to be rate of flux. The present data suggest that it occurs at a flux of approximately 120 nmol/min per mg of protein.
- Published
- 1977
- Full Text
- View/download PDF
129. Hypoxic pulmonary vasoconstriction in man: effects of hyperventilation.
- Author
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Bindslev L, Jolin-Carlsson A, Santesson J, and Gottlieb I
- Subjects
- Adult, Carbon Dioxide biosynthesis, Female, Humans, Male, Middle Aged, Oxygen administration & dosage, Oxygen metabolism, Respiration, Artificial, Ventilation-Perfusion Ratio, Hyperventilation physiopathology, Hypoxia physiopathology, Pulmonary Circulation, Vasoconstriction
- Abstract
The pulmonary vasoconstriction response to hypoxia was studied in eight anaesthetized supine subjects. One lung was made hypoxic while the other was ventilated with 100% oxygen. This was achieved by separating the tidal gas-distribution to the lungs by means of a double-lumen tracheal catheter. The hypoxic pulmonary vasoconstriction (HPV) response was estimated from the blood flow diversion away from the hypoxic lung. Blood flow distribution between the lungs was calculated from the regional expired carbon dioxide production, assuming regional carbon dioxide production to be proportional to blood flow. The subjects were studied during six different conditions. Firstly, when ventilated with 100% oxygen to both lungs at a PaCO2 of about 6 kPa. Secondly, with 100% oxygen to the left lung and 5% oxygen in nitrogen to the right (test) lung. The ratio between carbon dioxide output from right and left lung was calculated. These measurements were repeated during two states of hyperventilation (PaCO2 of about 4.5 kPa and 3.5 kPa, respectively) with and without hypoxia (conditions 3-6). During normoventilation, blood flow distribution between the lungs was equal. During hypoxia, blood flow distribution to the hypoxic lung decreased by 35% of the pre-hypoxic value. Furthermore, a decrease in arterial oxygen tension from 51.5 +/- 4.5 to 11.5 +/- 2.1 kPa was observed. During excessive hyperventilation (PaCO2 3.2 +/- 0.2 kPa), blood flow distribution to the hypoxic right lung decreased by only 10% of its pre-hypoxic value. A further decrease in arterial oxygen tension to 8.5 +/- 1.8 kPa was observed. This decrease in PaO2 was possibly due to an increased venous admixture caused by an abolished HPV response. It is concluded that hyperventilation counteracts hypoxic pulmonary vasoconstriction in man.
- Published
- 1985
- Full Text
- View/download PDF
130. Mammalian cells with defective mitochondrial functions: a Chinese hamster mutant cell line lacking succinate dehydrogenase activity.
- Author
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Soderberg KL, Ditta GS, and Scheffler IE
- Subjects
- Animals, Asparagine metabolism, Carbon Dioxide biosynthesis, Carbon Dioxide metabolism, Citric Acid Cycle, Cricetinae, Glucose metabolism, Glycerophosphates metabolism, Mitochondria metabolism, Oxygen Consumption, Succinates metabolism, Cell Line, Mitochondria enzymology, Mutation, Succinate Dehydrogenase metabolism
- Abstract
A mutant cell line derived from Chinese hamster fibroblasts is described which is defective in oxidative energy metabolism. Glucose is continuously required in the medium. As a result of a block in the Krebs cycle, these cells are auxotrophs for carbon dioxide and asparagine. Several experiments support our conclusion that the mutant cells lack appreciable levels of succinate dehydorgenase activity. Other components of the electron transport chain appear to be fully functional, although there is the possibility that electron transport and oxidative phosphorylation are uncoupled.
- Published
- 1977
- Full Text
- View/download PDF
131. Stimulation of ketogenesis by dibutyryl cyclic AMP in isolated rat hepatocytes.
- Author
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Cole RA and Margolis S
- Subjects
- Acetoacetates metabolism, Acetone metabolism, Albumins metabolism, Animals, Butyrates pharmacology, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Epinephrine pharmacology, Hydroxybutyrates metabolism, Liver cytology, Male, Rats, Bucladesine pharmacology, Ketone Bodies biosynthesis, Liver metabolism, Palmitic Acids metabolism
- Published
- 1974
- Full Text
- View/download PDF
132. Glucose oxidation in alveolar macrophages: pharmacologic features.
- Author
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Gee JB, Khandwala AS, McKeever PE, and Malawista SE
- Subjects
- Animals, Carbon Radioisotopes, Epinephrine pharmacology, In Vitro Techniques, Isoproterenol pharmacology, Macrophages drug effects, Oxidation-Reduction, Phagocytosis drug effects, Propranolol pharmacology, Pulmonary Alveoli drug effects, Rabbits, Staphylococcus metabolism, Bucladesine pharmacology, Carbon Dioxide biosynthesis, Glucose metabolism, Macrophages metabolism, Prostaglandins pharmacology, Pulmonary Alveoli cytology, Sympathomimetics pharmacology, Theophylline pharmacology
- Published
- 1974
133. Degradation of branched-chain amino acids and their derived 2-oxo acids and fatty acids in human and rat heart and skeletal muscle.
- Author
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Wagenmakers AJ and Veerkamp JH
- Subjects
- 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide), Animals, Carbon Dioxide biosynthesis, Humans, Ketone Oxidoreductases metabolism, Leucine metabolism, Male, Multienzyme Complexes metabolism, Muscles enzymology, Myocardium enzymology, Rats, Transaminases metabolism, Valine metabolism, Amino Acids, Branched-Chain metabolism, Keto Acids metabolism, Muscles metabolism, Myocardium metabolism
- Published
- 1982
- Full Text
- View/download PDF
134. Calorimetric validation of the doubly-labelled water method for determination of energy expenditure in man.
- Author
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Klein PD, James WP, Wong WW, Irving CS, Murgatroyd PR, Cabrera M, Dallosso HM, Klein ER, and Nichols BL
- Subjects
- Adult, Calorimetry methods, Deuterium, Diet, Evaluation Studies as Topic, Humans, Isotope Labeling, Male, Mathematics, Oxygen Isotopes, Carbon Dioxide biosynthesis, Energy Metabolism, Water metabolism
- Abstract
The turnover rates of water and carbon dioxide have been estimated at frequent intervals after a single dose of 2H2 18O had been given to an adult monitored continuously in a whole body calorimeter for 5 d. The integrated CO2 production rate for 5 d, estimated from the differential rates of 2H and 18O excretion in urine, was within 2 per cent of the actual CO2 output, based on an improved method of calculation. Changes occurred in the abundance of 2H and 18O in response to activity, so that the timing of samples was important. It was found better to compute the production rate of CO2 from multiple samples rather than from measurements at only two points of time. The proportion of total water lost by evaporation proved to be less than previously assumed. Direct validation of the technique requires calorimetric studies of 2 to 3 weeks duration, in either animals or human subjects. The potential value of this method for measurement of energy expenditure in man is such that exacting tests of its accuracy and precision are needed before it is adopted for general use in metabolic and epidemiological studies.
- Published
- 1984
135. Method for estimating the decomposition of hexadecane in the marine environment.
- Author
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Seki H
- Subjects
- Bacteria isolation & purification, Biodegradation, Environmental, Carbon Dioxide biosynthesis, Cell Count, Japan, Seasons, Seawater, Water Pollution, Chemical, Alkanes metabolism, Bacteria metabolism, Water Microbiology
- Abstract
A method, based on quantitating 14CO2 produced from [14C]hexadecane, has been developed for estimating the rate of hexadecane decomposition in seawater of Tokyo Bay during the summer stagnation period. The rate of hexadecane decomposition was from 0.1 to 1.3 mug/h per liter of seawater at the surface layer in the polluted gyre of the inner part of Tokyo Bay during the summer of 1974. A similar horizontal distribution pattern was seen for the density of hexadecane-decomposing bacteria.
- Published
- 1976
- Full Text
- View/download PDF
136. CO2 production of the chick embryo during the first day of post-laying development.
- Author
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Raddatz E and Kucera P
- Subjects
- 2,4-Dinitrophenol, Acetazolamide pharmacology, Animals, Antimycin A pharmacology, Blastoderm metabolism, Chick Embryo growth & development, Culture Techniques, Dinitrophenols pharmacology, Glucose pharmacology, Oxygen Consumption drug effects, Phenazines pharmacology, Uncoupling Agents pharmacology, Vitelline Membrane metabolism, Carbon Dioxide biosynthesis, Chick Embryo metabolism
- Abstract
The carbon dioxide production of the chick embryo cultured in vitro has been determined during the first 24 h of post-laying development using a non-invasive conductometric microtechnique. The mean CO2 production of the whole blastoderm (1) increased from 16 nmol/h at laying to 231 nmol/h at early neurulation, (2) became dependent on exogenous glucose and (3) was closely linked to mechanical tension generated in the blastoderm (loosening from vitelline membrane resulted in a decrease of 56%). In our experimental conditions, no significant influence of carbonic anhydrase on the CO2 production has been detected. The value of the respiratory exchange ratio varied from about 3 at pregastrular stages to 1 at neurula stage and CO2 was produced transiently in presence of antimycin A. Such results indicate that the source of CO2 is not exclusively mitochondrial and that the relative proportions of mitochondrial and non-mitochondrial CO2 productions might vary significantly throughout the early development. Our findings confirm that the metabolism of the chick embryo becomes more and more oxidative from laying onwards and suggest that the modifications of metabolism observed during the studied period of development could be associated with functional differentiation.
- Published
- 1988
- Full Text
- View/download PDF
137. Effects of temperature and crude oil composition on petroleum biodegradation.
- Author
-
Atlas RM
- Subjects
- Alkanes metabolism, Arctic Regions, Biodegradation, Environmental, Carbon Dioxide biosynthesis, Oxygen Consumption, Pseudomonas metabolism, Seawater, Bacteria metabolism, Hydrocarbons metabolism, Petroleum analysis, Temperature, Water Microbiology
- Abstract
The biodegradability of seven different crude oils was found to be highly dependent on their composition and on incubation temperature. At 20 C lighter oils had greater abiotic losses and were more susceptible to biodegradation than heavier oils. These light crude oils, however, possessed toxic volatile components which evaporated only slowly and inhibited microbial degradation of these oils at 10 C. No volatile toxic fraction was associated with the heavier oils tested. Rates of oil mineralization for the heavier oils were significantly lower at 20 C than for the lighter ones. Similar relative degradation rates were found with a mixed microbial community, using CO2 evolution as the measure, and with a Pseudomonas isolate from the Arctic, using O2 consumption as the measure. The paraffinic, aromatic, and asphaltic fractions were subject to biodegradation. Some preference was shown for paraffin degradation, especially at low temperatures. Branched paraffins, such as pristane, were degraded at both 10 and 20 C. At best, a 20% residue still remained after 42 days of incubation. Oil residues generally had a lower relative percentage of paraffins and higher percentage of asphaltics than fresh or weathered oil.
- Published
- 1975
- Full Text
- View/download PDF
138. Effect of cytochalasin B on hexose transport and glucose metabolism in pancreatic islets.
- Author
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McDaniel ML, King S, Anderson S, Fink J, and Lacy PE
- Subjects
- Animals, Biological Transport, Active drug effects, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Cell Membrane Permeability, Cell Separation, Dimethyl Sulfoxide, Extracellular Space, Islets of Langerhans metabolism, Male, Microbial Collagenase, Rats, Sucrose metabolism, Temperature, Cytochalasin B pharmacology, Glucose metabolism, Hexoses metabolism, Islets of Langerhans drug effects
- Published
- 1974
- Full Text
- View/download PDF
139. Hypogravity-induced inhibition of CO2 production from amino acids in higher plants.
- Author
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Oputa CO and Mazelis M
- Subjects
- Amino Acids metabolism, Rotation, Carbon Dioxide biosynthesis, Gravitation, Plants metabolism
- Published
- 1974
- Full Text
- View/download PDF
140. The effects of cyclopropane carboxylate on hepatic pyruvate metabolism.
- Author
-
Steinhelper ME and Olson MS
- Subjects
- Animals, Carbon Dioxide biosynthesis, Gluconeogenesis drug effects, Ketone Bodies biosynthesis, Lactates metabolism, Lactic Acid, Liver drug effects, Male, NAD metabolism, Perfusion, Pyruvate Decarboxylase metabolism, Pyruvic Acid, Rats, Rats, Inbred Strains, Acyl Coenzyme A pharmacology, Cyclopropanes pharmacology, Liver metabolism, Pyruvates metabolism
- Abstract
The effects of cyclopropane carboxylate on gluconeogenesis and pyruvate decarboxylation from [1-14C]-labeled pyruvate and lactate were investigated in perfused livers from fasted rats. With high concentrations of pyruvate (greater than or equal to 0.5 mM) in the perfusion medium, infusion of cyclopropane carboxylate inhibited pyruvate decarboxylation and gluconeogenesis by 30 and 40%, respectively. With low, more physiological concentrations of pyruvate (50 microM) or with lactate (1 mM), cyclopropane carboxylate, at a concentration which elicits maximal inhibition of pyruvate decarboxylation from pyruvate (greater than or equal to 0.5 mM), did not affect either pyruvate decarboxylation or gluconeogenesis. Evidence is presented for the rapid formation of the coenzyme-A ester of cyclopropane carboxylate in perfused livers. Infusion of l-(-)carnitine (20 mM) prevented the inhibitory effects of cyclopropane carboxylate on pyruvate decarboxylation and gluconeogenesis from pyruvate (greater than or equal to 0.5 mM). Interestingly, no decrease in the tissue level of cyclopropanecarboxyl-CoA occurs under these conditions. The present study suggests that cyclopropane carboxylate, through a presently ill-defined mediator, inhibits pyruvate decarboxylation and gluconeogenesis by interfering with the pyruvate----oxalacetate----phosphoenolpyruvate----pyruvate cycle when pyruvate (greater than or equal to 0.5mM) supports gluconeogenesis.
- Published
- 1985
- Full Text
- View/download PDF
141. Neonatal energy transformation.
- Author
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Schulze KF
- Subjects
- Calorimetry, Carbon Dioxide biosynthesis, Eating, Heart physiology, Heart Rate, Humans, Infant, Premature, Oxygen Consumption, Respiratory Physiological Phenomena, Sleep Stages, Starvation metabolism, Energy Metabolism, Infant, Newborn
- Published
- 1985
142. Importance of pulmonary ventilation in respiratory control in the bullfrog.
- Author
-
Gottlieb G and Jackson DC
- Subjects
- Animals, Carbon Dioxide biosynthesis, Carbon Dioxide blood, Female, Hydrogen-Ion Concentration, Male, Oxygen blood, Time Factors, Lung metabolism, Oxygen Consumption, Rana catesbeiana physiology, Respiration, Skin metabolism
- Abstract
Pulmonary and cutaneous O2 consumption (Vo2) and CO2 production (Vco2) were measured simultaneously in bullfrogs Rana catesbeiana at 20 degrees C. The lungs were responsible for 77.3-91.0% of the total Vo2 and 28.5-74.9% of the total VCO2. The distribution of the total exchange between the lungs and skin depended on metabolic rate; frogs with higher rates relied more heavily on the pulmonary mode for both Vo2 and Vco2. When prevented from ventilating their lungs in an O2-rich environment, bullfrogs developed severe respiratory acidosis, demonstrating the importance of lung exchange in normal acid-base balance. When frogs were totally submerged in an O2-saturated medium, skin Vco2 increased linearly to a steady-state value which approximated the preapneic total Vco2. In these same animals, arterial Pco2 increased proportionately to the increase in skin Vco2, indicating that skin diffusion capacity for CO2 was unaffected. We conclude that the control of breathing in the bullfrog in response to changes in metabolic rate relies predominantly on changes in lung ventilation while the skin plays a more passive role.
- Published
- 1976
- Full Text
- View/download PDF
143. Effects of aminonucleoside, daunomycin, and adriamycin on carbon oxidation by glomeruli.
- Author
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Kaplan BS, Renaud L, and Drummond KN
- Subjects
- Animals, Blood Proteins analysis, Carbon Dioxide biosynthesis, Carbon Radioisotopes, Dose-Response Relationship, Drug, Drug Administration Schedule, Drug Antagonism, Glutamine metabolism, Hypercholesterolemia chemically induced, Kidney Glomerulus metabolism, Male, Nephrotic Syndrome chemically induced, Oxidation-Reduction, Proteinuria chemically induced, Pyruvates metabolism, Rats, Adenine pharmacology, Daunorubicin pharmacology, Doxorubicin pharmacology, Glucose metabolism, Kidney Glomerulus drug effects, Puromycin analogs & derivatives, Puromycin Aminonucleoside pharmacology
- Abstract
The purpose of these experiments was to determine whether reported changes in substrate metabolism by isolated glomeruli from rats with aminonucleoside nephrosis could be explained by the glomerular changes associated with proteinuria or, alternatively, whether these metabolic changes and proteinuria were synchronous but causally unrelated events. Aminonucleoside of puromycin produced proteinuria within 7 days when injected intraperitoneally or subcutaneously. However, when aminonucleoside of puromycin as well as adenine were given, the onset of proteinuria was delayed until after day 7. A significant reduction in U-14C-glucose oxidation to CO2 was found at day 7 by glomeruli from rats given aminonucleoside of puromycin intraperitoneally but no significant changes were found with aminonucleoside of puromycin given subcutaneously on days 7 and 9 and aminonucleoside of puromycin + adenine given subcutaneously on days 7 and 9. Rats given daunomycin or adriamycin had developed proteinuria by day 14. U-14C-glucose oxidation to CO2 was significantly reduced on day 14 in glomeruli from rats given daunomycin but no significant changes were found on day 21 with daunomycin, or on days 14 and 21 with adriamycin. There was a reduction in pyruvic-acid carbon metabolism but not in glutamine-carbon oxidation 14 days after treatment with daunomycin. These results suggest that the observed changes in glomerular metabolism occur independently of, albeit synchronous with, the development of proteinuria. A causal relationship between these metabolic alterations and proteinuria therefore may be unlikely.
- Published
- 1976
144. Separation of viable Rickettsia typhi from yolk sac and L cell host components by renografin density gradient centrifugation.
- Author
-
Weiss E, Coolbaugh JC, and Williams JC
- Subjects
- Animals, Antigens, Bacterial analysis, Carbon Dioxide biosynthesis, Chick Embryo, Diatrizoate, Female, Glutamates metabolism, Hemolysis, Malate Dehydrogenase metabolism, Mice, Rickettsia typhi immunology, Rickettsia typhi metabolism, Centrifugation, Density Gradient methods, L Cells microbiology, Rickettsia typhi isolation & purification, Vitelline Membrane microbiology
- Abstract
Rickettsia typhi cultivated in the yolk sac of chicken embryos or in L cells irradiated 7 days previously was separated from host cell components by two cycles of Renografin density gradient centrifugation. Preliminary steps involved differential centrifugation and centrifugation over a layer of 10% bovine plasma albumin of infected yolk sac suspensions, or trypsinization and passage through filters of wide porosity of infected L cell suspensions. Rickettsial preparations obtained by these methods appeared to be free from host cell components while retaining high levels of hemolytic activity, egg infectivity, and capacity to catabolize glutamate. Average yields were 3.3 mg of rickettsial protein per yolk sac or 0.44 mg per 16-oz (ca. 475-ml) L cell culture. Extracts from these two preparations displayed malate dehydrogenase activity of electrophoretic mobility identical to each other but quite different in migration patterns from the corresponding host cell enzymes. This method of separation of rickettsiae from host cell constituents appears to be particularly well suited for the study of rickettsial enzymatic activity.
- Published
- 1975
- Full Text
- View/download PDF
145. Physiology of sporeforming bacteria associated with insects: metabolism of Bacillus popilliae grown in third-instar Popillia japonica Newman larvae.
- Author
-
St Julian G, Bulla LA Jr, and Hanson RS
- Subjects
- Acetates metabolism, Aerobiosis, Animals, Bacillus enzymology, Bacillus growth & development, Carbon Dioxide biosynthesis, Citric Acid Cycle, Glucose metabolism, Glutamates metabolism, Hemolymph metabolism, Insect Control, Ketoglutaric Acids metabolism, Larva microbiology, Pest Control, Biological, Pyruvates metabolism, Spores, Bacterial growth & development, Succinates metabolism, Bacillus metabolism, Coleoptera microbiology
- Abstract
The timing and relative participation of concurrent pathways of carbohydrate metabolism as well as the extent of terminal respiratory activity were determined by radiorespirometry with 14-C substrates and by enzyme assays for vegetative and sporulating cells of the bacterium Bacillus popilliae cultured in whole, intact Popillia japonica (Japanese beetle) larvae. During vegetative proliferation, the pentose phosphate pathway predominates in the bacterial cells with minor involvement of the Embden-Meyerhof-Parnas pathway. As the cells proceed through sporulation, pentose phosphate and Embden-Meyerhof-Parnas activity remains constant. No tricarboxylic cycle activity is evident during growth and sporulation of B. popilliae. The results demonstrate (i) predominantly aerobic metabolism for carbohydrate assimilation within in vivo sporulating cells, (ii) a major contrast to the metabolism of other aerobic sporeforming bacteria that exhibit derepression of tricarboxylic acid cycle enzymatic activity at the onset of sporulation, and (iii) no causal necessity of the cycle to B. popilliae sporogeny.
- Published
- 1975
- Full Text
- View/download PDF
146. Biological oxidation of [14C]methylene chloride to carbon monoxide and carbon dioxide by the rat.
- Author
-
Rodkey FL
- Subjects
- Animals, Breath Tests, Catalysis, Chemical Phenomena, Chemistry, Female, Male, Oxidation-Reduction, Rats, Time Factors, Carbon Dioxide biosynthesis, Carbon Monoxide biosynthesis, Hydrocarbons, Chlorinated metabolism, Methylene Chloride metabolism
- Published
- 1977
- Full Text
- View/download PDF
147. Renal gluconeogenesis and amino-acid metabolism in man.
- Author
-
Cahill GF Jr and Aoki TT
- Subjects
- Absorption, Acetyl Coenzyme A metabolism, Adipose Tissue metabolism, Ammonia metabolism, Brain metabolism, Carbon Dioxide biosynthesis, Fasting, Glucose biosynthesis, Glucose metabolism, Humans, Ketoglutaric Acids metabolism, Liver metabolism, Muscles metabolism, Nitrogen urine, Oxidation-Reduction, Phosphoenolpyruvate Carboxykinase (GTP) metabolism, Starvation urine, Tricarboxylic Acids metabolism, Amino Acids metabolism, Gluconeogenesis, Kidney metabolism
- Published
- 1975
- Full Text
- View/download PDF
148. Effect of 2-chloro-4,6-bis(ethylamino)-S-triazine (Simazine) on some soil microbial processes.
- Author
-
Weeraratna CS
- Subjects
- Ammonia metabolism, Bacteria metabolism, Carbon Dioxide biosynthesis, Nitrates metabolism, Nitrogen metabolism, Bacteria drug effects, Herbicides pharmacology, Simazine pharmacology, Soil Microbiology
- Published
- 1979
- Full Text
- View/download PDF
149. A quantitative bioassay to measure the rate of respiration of isolated rat tooth pulp tissue.
- Author
-
Levine LS, Marcus F, and de Kooker M
- Subjects
- Animals, Culture Techniques, Hydrogen-Ion Concentration, Incisor, Rats, Biological Assay methods, Carbon Dioxide biosynthesis, Dental Pulp metabolism
- Abstract
The formation of carbon dioxide, expressed as milligrammes of carbon dioxide per gramme wet weight, was used to determine the rate of succinate-induced respiration in rat incisal dental pulp, after incubation in a phosphate buffer. Seven experimental parameters: (a) physical nature of the tissue; (b) mass of the rat; (c) pre-incubation time; (d) incubation time; (e) substrate concentration; (f) effect of pH; and (g) effects of technique on pH, were analysed; pH was a critical determinant for success with this assay.
- Published
- 1987
- Full Text
- View/download PDF
150. The role of stress hormones in the catabolic metabolism of shock.
- Author
-
Liddell MJ, Daniel AM, MacLean LD, and Shizgal HM
- Subjects
- Animals, Blood Glucose analysis, Carbon Dioxide biosynthesis, Dogs, Dose-Response Relationship, Drug, Fatty Acids, Nonesterified metabolism, Female, Hormones administration & dosage, Infusions, Parenteral, Lactates blood, Muscle Proteins metabolism, Oxidation-Reduction, Oxygen metabolism, Shock, Cardiogenic metabolism, Urea biosynthesis, Epinephrine administration & dosage, Glucagon administration & dosage, Hydrocortisone administration & dosage, Shock metabolism
- Abstract
The role of catecholamines in shock metabolism in dogs was studied by comparing the metabolism of shock due to cardiac tamponade, shock with catecholamine depletion from prior reserpine adminstration and metabolism in the normal dog with continuous epinephrine infusion. It was concluded that the high serum concentrations of catecholamines in shock probably cause the increased blood lactate, initial hyperglycemia and, possibly, the poor free fatty acid oxidation seen in shock, but do not cause the increased protein catabolism of shock. With the simultaneous infusion of glucagon, cortisol and epinephrine in physiologic dosages, catabolic metabolism similar to that observed in shock was established in the normal dog. Lactacidemia, hyperglycemia, poor ability to oxidize free fatty acid and massive protein breakdown were observed. The decreased metabolic rate and diminished fatty acid mobilization of shock were not duplicated in those in the normal group and are probably a function of hypoperfusion. The importance of these observations is that impaired use of fat and increased protein breakdown, as seen in shock and trauma, are mediated by hormonal changes. It follows that there may be the opportunity to reverse or modify this catabolism by hormonal manipulation in the surgical patient.
- Published
- 1979
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