THE METABOLISM OF PELARGONATE-1-C14 BY WHEAT STEM RUST UREDOSPORES

1965 ◽  
Vol 43 (1) ◽  
pp. 91-96 ◽  
Author(s):  
S. Suryanarayanan ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Glyoxylate Cycle ◽  
Water Extract ◽  
Aminobutyric Acid ◽  
Pelargonic Acid ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Carbon 14 ◽  
The Glyoxylate Cycle

Uredospores of Puccinia graminis var. tritici were incubated in phosphate buffer (pH 6.2) containing pelargonic acid-1-C14. After 3 hours 97.5% of the tracer was assimilated. Fifty-five percent of this was released as C14O2 and 36.2% was incorporated into the spores. About one-half of the carbon-14 in the spores was soluble in ethanol and water, whereas nearly a third was ether extractable. The amino acid and carbohydrate fractions contained about equal amounts of carbon-14 and together accounted for two-thirds of the radioactivity in the ethanol–water extract. The organic acids were also radioactive. Glutamic acid, γ-aminobutyric acid, aspartic acid, and alanine were the most highly labelled amino acids. Fifty-three percent of the radioactivity in glutamic acid was found in carbon 1 and 46% in carbon 5. This distribution suggests β-oxidation of pelargonic acid to acetyl CoA and extensive utilization of the latter by means of the glyoxylate cycle.

THE METABOLISM OF PROPIONATE BY WHEAT STEM RUST UREDOSPORES

1963 ◽  
Vol 41 (3) ◽  
pp. 737-743 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell ◽  
G. A. Ledingham
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Stem Rust ◽  
Water Extract ◽  
Hot Water ◽  
Insoluble Residue ◽  
Soluble Carbohydrates ◽  
Wheat Stem Rust ◽  
Carbon 14

When uredospores of wheat stem rust were shaken for 3 hours with phosphate buffer (pH 6.2) containing propionate-1-C14, -2-C14, or -3-C14, about 55% of the carbon-14 was removed from the solution. With propionate-1-C14, most of the carbon-14 taken up was released as carbon dioxide-C14, whereas about 20% and 31% of propionate carbon 2 and carbon 3, respectively, was incorporated into the spores. The specific activity of a fraction consisting of the free amino acids of a hot-alcohol and hot-water extract of the spores increased markedly with increase in the position number of propionate in which the carbon-14 was located. A similar relation was observed for other fractions such as soluble carbohydrates, ether-soluble material, organic acids, and insoluble residue from spores. The most active amino acids isolated were glutamic acid, γ-aminobutyric acid, and alanine. Partial degradations showed that with propionate-2-C14 the carboxyl groups of glutamic acid were especially radioactive, whereas with propionate-3-C14 the internal carbons were most radioactive.It is concluded that propionate metabolism in the rust spores involved conversion of carbon 1 to carbon dioxide, and utilization of carbons 2 and 3 as acetate with carbon 2 behaving as the carboxyl carbon.

STUDIES ON THE METABOLISM OF VALERATE-1-C14 BY UREDOSPORES OF WHEAT STEM RUST

1961 ◽  
Vol 39 (10) ◽  
pp. 1559-1566 ◽  
Author(s):  
H. Reisener ◽  
W. B. McConnell ◽  
G. A. Ledingham
Keyword(s):  
Glutamic Acid ◽  
Soluble Fraction ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Water Soluble ◽  
Aminobutyric Acid ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Carbon 14 ◽  
Cellular Components

When uredospores of Puccinia graminis var. tritici race 15B were shaken in a medium containing M/30 phosphate buffer, pH 6.2, and valerate-1-C14, 97% of the radioactivity was removed from the solution in a period of 3 hours. Fifty-five per cent of the carbon-14 was released as carbon dioxide, and 42% was incorporated into the spores. Carbon-14 was found in many cellular components but the water-soluble fraction accounted for 48% of the tracer in the spores. About two thirds of the water-soluble carbon-14 was in a fraction containing amino acids, amides, and peptides, with glutamic acid, glutamine, and γ-aminobutyric acid being highly radioactive. Carbon-5 of glutamic acid and carbon-1 of γ-aminobutyric acid were particularly radioactive. In addition carbon-1 of glutamic acid was appreciably radioactive. The results are consistent with the view that γ-aminobutyric acid was formed by decarboxylation of glutamic acid and that glutamic acid became labelled as a result of β-oxidation of the valerate-1-C14 to yield acetate-1-C14 which in turn was metabolized by the tricarboxylic acid cycle.

THE METABOLISM OF PROPIONATE BY WHEAT STEM RUST UREDOSPORES

1963 ◽  
Vol 41 (1) ◽  
pp. 737-743 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell ◽  
G. A. Ledingham
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Stem Rust ◽  
Water Extract ◽  
Hot Water ◽  
Insoluble Residue ◽  
Soluble Carbohydrates ◽  
Wheat Stem Rust ◽  
Carbon 14

When uredospores of wheat stem rust were shaken for 3 hours with phosphate buffer (pH 6.2) containing propionate-1-C14, -2-C14, or -3-C14, about 55% of the carbon-14 was removed from the solution. With propionate-1-C14, most of the carbon-14 taken up was released as carbon dioxide-C14, whereas about 20% and 31% of propionate carbon 2 and carbon 3, respectively, was incorporated into the spores. The specific activity of a fraction consisting of the free amino acids of a hot-alcohol and hot-water extract of the spores increased markedly with increase in the position number of propionate in which the carbon-14 was located. A similar relation was observed for other fractions such as soluble carbohydrates, ether-soluble material, organic acids, and insoluble residue from spores. The most active amino acids isolated were glutamic acid, γ-aminobutyric acid, and alanine. Partial degradations showed that with propionate-2-C14 the carboxyl groups of glutamic acid were especially radioactive, whereas with propionate-3-C14 the internal carbons were most radioactive.It is concluded that propionate metabolism in the rust spores involved conversion of carbon 1 to carbon dioxide, and utilization of carbons 2 and 3 as acetate with carbon 2 behaving as the carboxyl carbon.

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 UTILIZATION OF AMMONIUM CHLORIDE-15N BY UREDOSPORES OF WHEAT STEM RUST

1966 ◽  
Vol 44 (11) ◽  
pp. 1511-1518 ◽  
Author(s):  
W. B. McConnell ◽  
E. W. Underhill
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Ammonium Chloride ◽  
Stem Rust ◽  
Organic Nitrogen ◽  
Ammonia Nitrogen ◽  
Ammonium Nitrogen ◽  
Wheat Stem Rust ◽  
Carbon 14

When uredospores of wheat stem rust, Puccinia graminis van tritici (race 15B), were incubated with a 3 mM solution of ammonium chloride-15N, a significant amount of nitrogen 15 was converted into organic nitrogen. Most of this organic nitrogen 15 was found in the ethanol and water extracts, with lesser amounts in the buffer and in extracted spores.Amino acids extracted from the spores all contained excess nitrogen 15. Nitrogen 15 from the inorganic source was diluted by factors of 1.7 and 2.7 in free aspartic and glutamic acids respectively; these amino acids were the most heavily labeled with the isotope. Proline was the most weakly labeled amino acid, the nitrogen 15 being diluted by a factor of 102. Good incorporation of nitrogen 15 into glutamic acid compared to simultaneous poor incorporation into the biochemically related amino acid, proline, parallels previous observations made during carbon 14 experiments with rust uredospores.Fourteen "bound" amino acids were isolated after acid hydrolysis of extracted spores. All contained nitrogen 15, the dilution of the added ammonia nitrogen ranging from 96 for glutamic acid to 7660 for proline.The results are taken as evidence that uredospores of wheat stem rust can incorporate ammonium nitrogen into free amino acids and into proteins.

THE METABOLISM OF VALERATE-3-C14 AND -5-C14 BY WHEAT STEM RUST UREDOSPORES

1964 ◽  
Vol 42 (3) ◽  
pp. 327-332 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Stem Rust ◽  
Phosphate Buffer ◽  
Free Amino Acids ◽  
Free Amino ◽  
Methyl Groups ◽  
Wheat Stem Rust ◽  
Carbon 14

Uredospores of wheat stem rust took up about 90% of the carbon-14 present either as valerate-3-C14 or as valerate-5-C14 in M/30 phosphate buffer pH 6.2 in 3 hours. The initial valerate concentration was 0.017 mM and spores were supplied at the rate of 250 mg/30 ml of buffer. Carbon 3 of the valerate was largely respired as carbon dioxide but carbon 5 was extensively incorporated into spore components. Free amino acids contained about 40% of the radioactivity in the spores labelled with valerate-5-C14 and glutamic acid was highly labelled. Carbon 1 contained 8.1% and carbon 5, 3.8% of the carbon-14 in this glutamic acid and thus internal carbons contained 88%. The results with valerate-3-C14 and with valerate-5-C14 compare well with those of experiments done earlier with propionate-1-C14 and propionate-3-C14 respectively. It is concluded that propionate is formed from carbons 3, 4, and 5 of valerate, and thus that carbon 3 is converted to carbon dioxide, and carbons 4 and 5 to the carboxyl and methyl groups respectively of acetate.

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.

STUDIES ON WHEAT PLANTS USING CARBON-14 LABELLED COMPOUNDS: X. THE INCORPORATION OF GLUTAMIC ACID-l-C14

1959 ◽  
Vol 37 (1) ◽  
pp. 933-936 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Wheat Plant ◽  
Protein Fractions ◽  
Appreciable Amount ◽  
Kernel Development ◽  
Carbon 14

Glutamic acid-1-C14 was injected into the top internode of wheat stems at a stage of growth when kernel development was rapid (71 days after seeding). The plants were harvested 31 days later when they had matured and the incorporation of carbon-14 studied. About one-third of the carbon-14 administered was found in the upper portions of the mature plants, much of the remaining radioactivity having apparently been respired. About 85% of the carbon-14 recovered was found in the kernel. The protein fractions of these were most radioactive, but an appreciable amount of carbon-14 also appeared in the starch. Glutamic acid had the highest specific activity of the amino acids isolated from the gluten, but proline and arginine were also strongly labelled. Since these three amino acids were labelled predominantly in carbon-1 their close metabolic relationship in the wheat plant seems probable.

STUDIES ON WHEAT PLANTS USING C14 COMPOUNDS: IV. DISTRIBUTION OF C14 IN GLUTAMIC ACID, ASPARTIC ACID, AND THREONINE ARISING FROM ACETATE-1-C14 AND -2-C14

1957 ◽  
Vol 35 (6) ◽  
pp. 365-371 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Citric Acid Cycle ◽  
Carbon Skeleton ◽  
Major Pathway ◽  
Acid Cycle ◽  
Carbon 14

Glutamic acid, aspartic acid, and threonine isolated from the gluten of wheat plants to which acetate-1-C14 or -2-C14 was administered during growth have been degraded to determine the complete intramolecular distribution of C14. Sixty-three per cent of the activity in glutamic acid arising from acetate-1-C14 was in carbon-5 and 20% in carbon-1; glutamic acid from acetate-2-C14 contained 43% of the activity in carbon-4 and about 18% in each of carbons 2 and 3. Acetate-1-C14 resulted in labelling largely in the terminal carbons of aspartic acid, and acetate-2-C14 preferentially labelled the internal carbons. The results show that the Krebs' citric acid cycle provides a major pathway for the biosynthesis of the dicarboxylic amino acids of wheat gluten.Striking parallelism in the intramolecular distribution of carbon-14 in aspartic acid and threonine demonstrates that these amino acids are closely linked biosynthetically and is in accord with the idea that aspartic acid provides the carbon skeleton for threonine.

Amino Acid Requirements for the Wheat Stem Sawfly Determined with Glucose-U-C14 after Vacuum-infiltration

1964 ◽  
Vol 96 (8) ◽  
pp. 1133-1137 ◽  
Author(s):  
R. Kasting ◽  
A. J. McGinnis
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Vacuum Infiltration ◽  
Artificial Diets ◽  
Isoleucine Leucine ◽  
Wheat Stem Sawfly ◽  
Carbon 14 ◽  
Amino Acid Requirements ◽  
Radioactive Substrate

AbstractGlucose-U-C14 was incorporated into immature larvae of the wheat stem sawfly, Cephus cinctus Nort., by vacuum-infiltration. These insects were too small to be conveniently injected and could not be easily fed on artificial diets. About half of them survived the infiltration treatment. C14O2 was produced by the organism showing that the radioactive substrate was metabolized. Of the amino acids isolated from the larvae, proline, alanine, glutamic acid, serine, aspartic acid, and glycine contained relatively large quantities of carbon-14 indicating biosynthesis, and are classed as nutritionally non-essential. In contrast, arginine, isoleucine, leucine, lysine, phenylalanine, threonine, tyrosine, and valine contained little, if any, radioactivity and are classed as nutritionally essential. The concentrations of some of the amino acids in the larval tissues are also presented.

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