STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XII. UTILIZATION OF SERINE-C14 WITH SPECIAL REFERENCE TO GLYCINE LABELLING

1960 ◽  
Vol 38 (1) ◽  
pp. 533-538 ◽  
Author(s):  
R. Nath ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Special Reference ◽  
Specific Activity ◽  
High Specific Activity ◽  
Wheat Plant ◽  
Total Carbon ◽  
Plant Parts ◽  
Carbon 14 ◽  
Direct Incorporation

Serine-C14 (uniformly labelled) was injected into the top internode of wheat plant stems and the distribution of carbon-14 in the mature plants (harvested 24 days after injection) was studied. Fifty-six per cent of the carbon-14 injected was found in upper plant parts but only trace amounts occurred below the top internode. The kernels contained 48% of the tracer injected while only 4% remained in the stem. Gluten had the highest specific activity of any major kernel component, serine and glycine accounting for one third of the total carbon-14 of the protein. The high specific activity of serine in gluten indicates its direct incorporation into kernel proteins. The specific activity of the glycine was almost equal to that of serine. Since similar experiments with glycine-1-C14 have yielded gluten with highly radioactive serine-1-C14, the ready interconvertibility of these two amino acids is demonstrated. The results indicate that interconversion takes place, at least in part, by the reversible condensation of "active" formate with carbon-2 of the glycine but that alternate pathways may also operate.

STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XII. UTILIZATION OF SERINE-C14 WITH SPECIAL REFERENCE TO GLYCINE LABELLING

1960 ◽  
Vol 38 (6) ◽  
pp. 533-538 ◽  
Author(s):  
R. Nath ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Special Reference ◽  
Specific Activity ◽  
High Specific Activity ◽  
Wheat Plant ◽  
Total Carbon ◽  
Plant Parts ◽  
Carbon 14 ◽  
Direct Incorporation

Serine-C14 (uniformly labelled) was injected into the top internode of wheat plant stems and the distribution of carbon-14 in the mature plants (harvested 24 days after injection) was studied. Fifty-six per cent of the carbon-14 injected was found in upper plant parts but only trace amounts occurred below the top internode. The kernels contained 48% of the tracer injected while only 4% remained in the stem. Gluten had the highest specific activity of any major kernel component, serine and glycine accounting for one third of the total carbon-14 of the protein. The high specific activity of serine in gluten indicates its direct incorporation into kernel proteins. The specific activity of the glycine was almost equal to that of serine. Since similar experiments with glycine-1-C14 have yielded gluten with highly radioactive serine-1-C14, the ready interconvertibility of these two amino acids is demonstrated. The results indicate that interconversion takes place, at least in part, by the reversible condensation of "active" formate with carbon-2 of the glycine but that alternate pathways may also operate.

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 CARBON-14 COMPOUNDS: XXI. THE METABOLISM OF GLYCINE-2-C14

1964 ◽  
Vol 42 (9) ◽  
pp. 1293-1299 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Total Carbon ◽  
Gluten Protein ◽  
Carbon 14 ◽  
Specific Activities

Glycine-2-C14was administered to 83-day-old wheat plants. The plants were allowed to mature fully and the carbon-14 distribution was then examined. About 80% of the radioactivity injected was recovered in the upper portions of the plant, the kernels themselves containing 66%. Proteins had a higher specific activity than other kernel constituents but the starch contained about one-half the total carbon-14 of the kernels. Glycine and serine were by far the most radioactive amino acids of the gluten protein. They had specific activities of 2720 and 2900 μc/mole C respectively while alanine, histidine, methionine, glutamic acid, and proline had specific activities ranging from 150 to 300 μc/mole C. The specific activities of carbons 1 and 2 of glycine recovered from the protein were 550 and 4900 μc/mole respectively while the specific activities of carbons 1, 2, and 3 of serine were 490, 4300, and 3100 μc/mole respectively. The results confirm previous views regarding extensive interconversion of glycine and serine in maturing wheat. Extensive labelling in carbon 3 of serine is interpreted as evidence that glycine is degraded to "active formaldehyde" and carbon dioxide.

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

1959 ◽  
Vol 37 (8) ◽  
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.

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 C14 COMPOUNDS: VII. UTILIZATION OF PYRUVATE-2-C14

1958 ◽  
Vol 36 (1) ◽  
pp. 381-388 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Active Carbon ◽  
Specific Activity ◽  
Carboxyl Groups ◽  
Gluten Protein ◽  
Carbon 14 ◽  
Soluble Material

Approximately half of the carbon-14 injected into the stems of wheat plants in the form of pyruvate-2-C14 remained in the plant at maturity, 30 days later. Almost 90% of this had accumulated in the kernel. Appreciable activity was found in the major components, protein, starch, ether-soluble material, and a residue termed bran. The amino acids of the gluten protein differed markedly from one another in specific activity. Glutamic acid and the related amino acids, arginine and proline, were most active, their specific activity decreasing in that order. Fifty-two per cent of the carbon-14 in glutamic acid was in carbon-5, while carbon-1 contained 21%. Seventy per cent of the radioactivity of aspartic acid was divided almost equally between the terminal carboxyl groups. The results are similar to those previously observed using acetate-1-C14 as tracer, and it is concluded that administered pyruvate-2-C14 undergoes extensive decarboxylation to form acetate-1-C14. The most active carbon in alanine from the pyruvate-2-C14 was carbon-1. This observation is not in accord with the theory that alanine is formed directly from pyruvate by transamination.

scholarly journals Continuous C14O2 and CO2 Excretion Studies in Experimental Animals

1956 ◽  
Vol 185 (2) ◽  
pp. 269-274 ◽  
Author(s):  
B. M. Tolbert ◽  
Martha Kirk ◽  
E. M. Baker
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Continuous Measurement ◽  
Specific Activity ◽  
Total Activity ◽  
Large Animal ◽  
Labeled Compounds ◽  
Experimental Animals ◽  
Carbon 14 ◽  
Co2 Excretion

An apparatus has been devised which permits, after administration of labeled compounds to animals, the continuous measurement and recording of CO2 excretion by means of infrared absorption, C14 excretion by ion chambers, and specific activity by a ratio analyzer. Comparative excretion studies have been made using labeled amino acids, fats, fatty acids and sugars. The specific activity and total activity rate curves for breath carbon-14 are markedly different. The generally smooth nature of the specific activity curves gives an excellent indication of the continuous and steady processes by which radioactivity is distributed into the various body pools. Studies have been made with mice, rats, guinea pigs and rabbits. As small an amount as 0.1 µc C14 has been used for an 8-hour study in mice. The instrument can be readily adapted for use in large animal or human studies following administration of small amounts of C14.

scholarly journals DNA sequence homology between the terminal inverted repeats of Shope fibroma virus and an endogenous cellular plasmid species

1986 ◽  
Vol 6 (1) ◽  
pp. 265-276
Author(s):  
C Upton ◽  
G McFadden
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sequence Homology ◽  
Inverted Repeat ◽  
Specific Activity ◽  
High Specific Activity ◽  
Cesium Chloride ◽  
Open Reading Frame ◽  
Terminal Inverted Repeat ◽  
Reading Frame

DNA hybridization experiments indicate that the genome of a tumorigenic poxvirus. Shope fibroma virus (SFV), possesses sequence homology with DNA isolated from uninfected rabbit cells. Southern blotting experiments, either with high-complexity rabbit DNA as probe and SFV restriction fragments as targets or with high-specific activity, 32P-labeled, cloned SFV sequences as probes and rabbit DNA as target, indicate that the homologous sequences map at two locations within the viral genome, one in each copy of the terminal inverted repeat sequences. Unexpectedly, Southern blots revealed that the homologous host sequences reside in a rabbit extrachromosomal DNA element. This autonomous low-molecular-weight DNA species could be specifically amplified by cycloheximide treatment and was shown by isopycnic centrifugation in cesium chloride-ethidium bromide to consist predominantly of covalently closed circular DNA molecules. DNA sequencing of pSIC-9, a cloned 1.9-kilobase fragment of the rabbit plasmid species, indicated extensive homology at the nucleotide level over a 1.5-kilobase stretch of the viral terminal inverted repeat. Analysis of open reading frames in both the plasmid and SFV DNA revealed that (i) the N-terminal 157-amino acid sequence of a potential 514-amino acid SFV polypeptide is identical to the N-terminal 157 amino acids of one pSIC-9 open reading frame, and (ii) a second long pSIC-9 open reading frame of 361 amino acids, although significantly diverged from the comparable nucleotide sequence in the virus, possessed considerable homology to a family of cellular protease inhibitors, including alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III. The potential role of such cellular plasmid-like DNA species as a mediator in the exchange of genetic information between the host cell and a cytoplasmically replicating poxvirus is discussed.

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