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.

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.

THE METABOLISM OF ACETATE BY WHEAT STEM RUST UREDOSPORES

1964 ◽  
Vol 42 (6) ◽  
pp. 883-888 ◽  
Author(s):  
S. Suryanarayanan ◽  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Water Soluble ◽  
Puccinia Graminis ◽  
Acid Fraction ◽  
Wheat Stem Rust ◽  
Acid Cycle ◽  
Carbon 14

When uredospores of Puccinia graminis var. tritici (race 15B) were incubated at pH 6.2 in phosphate buffer containing either acetate-1-C14or -2-C14, about 12% of the radioactivity was removed from the solution in a period of 3 hours. Respired carbon dioxide contained about 45% and 22% of the carbon-14 taken up as acetate-1-C14and acetate-2-C14, respectively. Incorporation of carbon-14 into spore components was considerably higher with acetate-2-C14than with acetate-1-C14. With either tracer most of the radioactivity in water-soluble spore materials was accounted for in amino acids and neutral substances. Glutamic acid was particularly radioactive and accounted for about 40% of the radioactivity in the amino acid fraction. Incorporation of carbon-14 into the glutamic acid skeleton was consistent with the view that both the tricarboxylic acid cycle and the glyoxalate cycle were functioning.

THE METABOLISM OF VALERATE-2-C14 BY UREDOSPORES OF WHEAT STEM RUST

1963 ◽  
Vol 41 (1) ◽  
pp. 1-7 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
High Specific Activity ◽  
Water Soluble ◽  
Buffer Solution ◽  
Wheat Stem Rust ◽  
Carbon 14 ◽  
Water Soluble Extract

When uredospores of Puccinia graminis var. tritici race 15B were shaken in a medium containing M/30 phosphate buffer, pH 6.2, and valerate-2-C14, about 88% of the radioactivity was removed from the buffer solution in a period of 3 hours. About 40% of the carbon-14 taken from the buffer was found in a water-soluble extract of the spores and about 15% was respired as carbon dioxide. The result is compared with an earlier report that carbon 1 of valerate is more extensively released as carbon dioxide and less extensively incorporated into spore components. Glutamic acid, glutamine, γ-aminobutyric acid, and alanine of high specific activity were isolated. It was estimated from partial degradation that more than one-half of the carbon-14 of glutamic acid occurred in position 4 and that carbon 5 was very weakly labelled. Citric acid was also of high specific activity and was labelled predominantly in the internal carbons.It is concluded that respiring rust spores utilize externally supplied valerate by β-oxidation, which releases carbons 1 and 2 in a form which is metabolized as acetate by the tricarboxylic acid cycle.

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.

Studies on wheat plants using 14C-labelled compounds. XXII. Incorporation into wheat protein

1969 ◽  
Vol 47 (1) ◽  
pp. 19-23 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Glutamic Acid ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Radioactive Tracers ◽  
Wheat Protein ◽  
Acid Cycle ◽  
Late Stages ◽  
Kernel Protein

Thatcher wheat plants were labelled with 14C by injecting radioactive tracers into the top internode of the stem during late stages of plant growth. The distribution of 14C in fully mature plants was examined, emphasis being placed on the labelling of kernel-protein amino acids.Glutamine was only slightly more effective than glutamic acid for labelling glutamic acid isolated from the gluten hydrolysate, indicating that glutamic acid and glutamine are extensively interconverted in the wheat plants. Proline and glutamic acid also are readily interconverted, proline-14C yielding protein in which the glutamic acid has a higher specific activity than does the proline. By contrast, arginine-5-14C did not yield highly labelled glutamic acid.14C from glyoxylate-1-14C was widely distributed among kernel components but it produced glycine and serine with carboxyl carbons of exceptionally high specific activity.Succinate-1,4-14C, succinate-2,3-14C, and aspartic acid-14C all labelled glutamic acid of kernel protein more extensively than the other amino acids of the protein. The role of the tricarboxylic acid cycle in utilizing these tracers is discussed.

scholarly journals Metabolic Activity Related to the Potassium Pump in the Midgut of Bombyx Mori Larvae

1985 ◽  
Vol 116 (1) ◽  
pp. 69-78
Author(s):  
P. PARENTI ◽  
B. GIORDANA ◽  
V. F. SACCHI ◽  
G. M. HANOZET ◽  
A. GUERRITORE
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Electrical Potential ◽  
Tricarboxylic Acid ◽  
Electrical Potential Difference ◽  
Acid Cycle

The transepithelial electrical potential difference across the isolated midgut of Bombyx mori larvae is dependent on the presence of potassium and is unaffected by the addition of hexoses to perfusion media, whereas it is enhanced by alanine, aspartic acid, glutamic acid and the corresponding 2- oxoacids, glutamine and malate. The midgut enzyme profile indicates that the substrates for the tricarboxylic acid cycle are supplied mainly by amino acid metabolism via transaminases. Accordingly, aminoxyacetate drastically reduces the intestinal transepithelial electrical potential difference stimulated by amino acids. Measurement of the free amino acid concentration in the lumen content, intestinal cells and haemolymph shows that glutamic acid, asparagine and glutamine are accumulated in the cell, whilst the haemolymph is enriched with basic amino acids and with glycine, alanine, serine and tyrosine, the major components of the silk fibroin. Therefore, amino acid metabolism directly related to the tricarboxylic acid cycle seems to be the primary source of energy for the potassium pump activity in B. mori midgut.

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

THE METABOLISM OF VALERATE-2-C14 BY UREDOSPORES OF WHEAT STEM RUST

1963 ◽  
Vol 41 (1) ◽  
pp. 1-7 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
High Specific Activity ◽  
Water Soluble ◽  
Buffer Solution ◽  
Wheat Stem Rust ◽  
Carbon 14 ◽  
Water Soluble Extract

When uredospores of Puccinia graminis var. tritici race 15B were shaken in a medium containing M/30 phosphate buffer, pH 6.2, and valerate-2-C14, about 88% of the radioactivity was removed from the buffer solution in a period of 3 hours. About 40% of the carbon-14 taken from the buffer was found in a water-soluble extract of the spores and about 15% was respired as carbon dioxide. The result is compared with an earlier report that carbon 1 of valerate is more extensively released as carbon dioxide and less extensively incorporated into spore components. Glutamic acid, glutamine, γ-aminobutyric acid, and alanine of high specific activity were isolated. It was estimated from partial degradation that more than one-half of the carbon-14 of glutamic acid occurred in position 4 and that carbon 5 was very weakly labelled. Citric acid was also of high specific activity and was labelled predominantly in the internal carbons.It is concluded that respiring rust spores utilize externally supplied valerate by β-oxidation, which releases carbons 1 and 2 in a form which is metabolized as acetate by the tricarboxylic acid cycle.

scholarly journals Transamination of glutamate to tricarboxylic acid-cycle intermediates in cultured neurons correlates with the ability of oxo acids to support neuronal survival in vitro

1986 ◽  
Vol 234 (3) ◽  
pp. 605-610 ◽  
Author(s):  
L Facci ◽  
S D Skaper ◽  
S Varon
Keyword(s):  
Amino Acid ◽  
Neuronal Survival ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Neuronal Cultures ◽  
Acid Cycle ◽  
Ciliary Ganglion Neurons ◽  
Amino Acid Precursors ◽  
Ganglion Neurons

Cultures of central-nervous-system neurons at low densities require for their survival exogenous pyruvate, alpha-oxoglutarate or oxaloacetate, even in the presence of high glucose concentrations. Most other alpha-oxo acids support cell survival only in the presence of alpha-amino acids which transaminate to alpha-oxoglutarate, oxaloacetate or pyruvate. The alpha-oxo acids therefore operate as acceptors of amino groups from appropriate donors to generate tricarboxylic acid-cycle-relevant substrates, and these alpha-oxo acids provide for neuronal support only insofar as they make it possible for exogenously supplied alpha-amino acid precursors to generate intracellularly one of the three critical metabolites. To examine more closely the relationship between transamination activity and neuronal survival, we measured 14CO2 production from [14C]glutamate in the presence of appropriate alpha-oxo acid partners by using 8-day-embryonic chick forebrain, dorsal-root-ganglion and ciliary-ganglion neurons. Neuronal survival was measured concurrently in monolayer neuronal cultures maintained with the corresponding amino acid/oxo acid pairs. Forebrain and ganglionic cell suspensions both produced 14CO2 from [14C]glutamate, which accurately correlated with 24 h neuronal survival. Concentrations of glutamate or alpha-oxo acid which provide for maximal neuronal survival also produced maximal amounts of 14CO2. The same ability to generate CO2 from glutamate (in the presence of the appropriate alpha-oxo acids) can ensure neuronal survival in 24 h cultures and therefore must meet energy or other metabolic needs of those neurons which glucose itself is unable to satisfy.

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