scholarly journals THE QUANTITATIVE HISTOCHEMISTRY OF THE SYMPATHOADRENAL SYSTEM II. ENZYMES OF THE CITRIC ACID, PENTOSE PHOSPHATE AND GLYCOGENOLYTIC PATHWAYS

1973 ◽  
Vol 21 (5) ◽  
pp. 483-487
Author(s):  
JAMES S. NELSON
Keyword(s):  
Citric Acid ◽  
Pentose Phosphate Pathway ◽  
Sympathetic Ganglion ◽  
Citric Acid Cycle ◽  
Sympathetic Neurons ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Pentose Phosphate ◽  
The Other ◽  
Acid Cycle ◽  
Neuronal Groups

The activities of enzymes from the citric acid cycle, pentose phosphate pathway and glycogen cycle were measured in collections of sympathoadrenal cells and compared with other neuronal groups. Enzymes from each pathway are found in groups of sympathetic neurons and adrenal medullary cells. The citric acid cycle has the highest capacity among glucose pathways in sympathoadrenal cells. Differences in glycolytic and citric acid cycle capacities between sympathetic ganglion and the other neuronal groups may be related to differences in capillary density. The capacity of the pentose phosphate pathway and reduced nicotinamide adenine dinucleotide phosphate-linked isocitric dehydrogenase is higher in sympathoadrenal cells than in the other cells surveyed. The enzyme activities in sympathetic ganglion are in excess of those needed to sustain the rates of glucose metabolism previously observed in this structure.

Carbon Isotope Fractionation by Autotrophic Bacteria with Three Different C02 Fixation Pathways

1989 ◽  
Vol 44 (5-6) ◽  
pp. 397-402 ◽  
Author(s):  
Andrea Preuß ◽  
Rolf Schauder ◽  
Georg Fuchs ◽  
Willibald Stichler
Keyword(s):  
Citric Acid ◽  
Carbon Isotope ◽  
Isotope Fractionation ◽  
Citric Acid Cycle ◽  
Pentose Phosphate ◽  
Acetobacterium Woodii ◽  
Acetyl Coa ◽  
Acid Cycle ◽  
Acetyl Coa Pathway ◽  
Cell Carbon

Abstract Carbon isotope fractionation during autotrophic growth o f different bacteria which possess different autotrophic CO2 fixation pathways has been studied. 13C /12C -Ratios in the cell carbon of the following bacteria were determined (CO2 fixation pathway suggested or proven in paren­theses): Alkaligenes eutrophus (reductive pentose phosphate cycle), Desulfobacterium autotrophicum and Acetobacterium woodii (reductive acetyl-CoA pathway), Desulfobacter hydrogenophilus and Thermoproteus neutrophilus (reductive citric acid cycle). The Δδ13C values, which indicate the per mille deviation of the 13C content of cell carbon from that of the CO : used as the sole carbon source, range from - 10%° (reductive citric acid cycle) over - 26%° (reductive pentose phosphate cycle) to -36%° (reductive acetyl-CoA pathway). Acetate formed via the acetyl-CoA pathway by the acetogenic Acetobacterium woodii showed a Δδ13C = -40%°. These data are discussed in view of the different CO2 fixation reactions used by the bacteria and especially with regard to the isotopic composition of sedimentary carbon through time.

PATHWAYS OF CARBOHYDRATE METABOLISM IN LOBSTER HEPATOPANCREAS

1962 ◽  
Vol 40 (8) ◽  
pp. 1043-1050 ◽  
Author(s):  
P. W. Hochachka ◽  
J. M. Teal ◽  
M. Telford
Keyword(s):  
Citric Acid ◽  
Oxygen Uptake ◽  
Carbohydrate Metabolism ◽  
Citric Acid Cycle ◽  
The Other ◽  
Short Term ◽  
Acid Cycle

Oxygen uptake by homogenates of lobster hepatopancreas was stimulated by the addition of Embden–Meyerhof, pentose cycle, and citric acid cycle intermediates as well as xylose. Acetate-1-C14oxidation was blocked by fluoracetate and glucose-1-C14oxidation fell by 80% with iodoacetate treatment. TPN and DPN increased glucose-1-C14oxidation by 140% and 20% and acetate-1-C14oxidation by 50% and 100% respectively. Large amounts of C14enter polysaccharide following treatment with glucose-1-C14or acetate-1-C14but very little enters after treatment with the same amount of gluconate-1-C14. Gluconate and xylose oxidation occurs in mitochondria-free preparations. In short-term tests with acetate-1-C14as substrate, most of the label in glycogen is on carbons 3 and 4 and the amount in the other positions can be explained on the basis of a 5–10% participation of the pentose cycle.

Studies in relation to biosynthesis. XLI. Canescin

1969 ◽  
Vol 22 (11) ◽  
pp. 2429 ◽  
Author(s):  
AJ Birch ◽  
F Gager ◽  
L Mo ◽  
A Pelter ◽  
JJ Wright
Keyword(s):  
Citric Acid ◽  
Carbon Atom ◽  
Citric Acid Cycle ◽  
Lactone Ring ◽  
Carbon Chain ◽  
The Other ◽  
Methoxyl Group ◽  
Acid Cycle ◽  
Polyketide Chain

The biosynthesis of canescin (I) has been investigated. The isocoumarin portion is derived from a polyketide chain. One carbon atom of the γ- lactone ring and the carbon atom of the methoxyl group originate from methionine whilst the other three carbon atoms of the γ-lactone have a symmetrical C4-acid of the citric acid cycle as their precursor. This metabolite is most unusual in that an oxygenated methionine-derived carbon atom provides the growing point of a new carbon chain. A possible mechanism for the attachment of the lactone is suggested.

Citric acid cycle in certain alterations of acid-base balance in human subjects

1961 ◽  
Vol 16 (4) ◽  
pp. 593-596 ◽  
Author(s):  
Wilbert Gamble ◽  
James M. Orten ◽  
Arthur H. Smith
Keyword(s):  
Citric Acid ◽  
Urinary Excretion ◽  
Citric Acid Cycle ◽  
Human Subjects ◽  
Statistical Significance ◽  
The Other ◽  
Acid Base Balance ◽  
Acid Base ◽  
Acid Cycle ◽  
Base Balance

An accurate chromatographic (silica gel) procedure for the quantitative measurement of the stable citric acid cycle acids and certain noncycle acids in urine was developed. The identity of the isolated acids was verified by paper chromatography. The method was applied to a study of urinary excretion of the cycle and other acids during certain alterations in acid-base balance in eight normal subjects, and one diabetic patient. During a “basic” regimen, the “alkaline tide,” and “respiratory alkalosis,” a significant increase in the excretion of citric acid occurred, with no significant change in that of the other cycle and noncycle acids. The “acidic” regimen produced a uniform decrease in the excretion of citrate to values approaching statistical significance; there was no consistent alteration in the excretion of the other acids. A similar decrease in the excretion of citric acid was observed in the patient during diabetic acidosis. It is concluded that of the Krebs cycle and other acids studied, the urinary excretion of only citric acid varies with alterations in acid-base balance. Submitted on February 10, 1961

ENZYMOLOGISCHE STUDIEN AM ARRHENOBLASTOM

1971 ◽  
Vol 67 (3) ◽  
pp. 577-589 ◽  
Author(s):  
H. Brandau ◽  
L. Brandau
Keyword(s):  
Enzyme Activity ◽  
Citric Acid ◽  
Enzyme Activities ◽  
Citric Acid Cycle ◽  
Hydroxysteroid Dehydrogenase ◽  
Pentose Phosphate ◽  
Testosterone Metabolism ◽  
Acid Cycle ◽  
Enzyme Activity Pattern ◽  
Pentose Phosphate Shunt

ABSTRACT In an arrhenoblastoma of a 24 years old female patient the enzyme activities of the intermediary carbonhydrate metabolism, the citric acid cycle, the glycerophosphate cycle, the pentose-phosphate shunt as well as the steroid-dehydrogenases were measured quantitatively and localized histochemically. The striking high activities of the glycolytic enzymes, the presence of steroid-dehydrogenases and the only moderately increased enzyme activities of the citric acid cycle in comparison with the stroma ovarii identify the arrhenoblastoma as a tissue with steroid hormonal metabolism. High activities of the mentioned enzymes and especially the activities of the steroid-dehydrogenases were localized histochemically only in Leydig-cell-like cells. Therefore these cells may be considered as structures of steroid-biogenesis. The enzyme activity pattern of the steroiddehydrogenases illuminates the biogenetic pathways of androgens. The low activities of the 17β-hydroxysteroid-dehydrogenase in this tissue in comparison with other steroid producing tissues indicate a special testosterone metabolism.

PATHWAYS OF CARBOHYDRATE METABOLISM IN LOBSTER HEPATOPANCREAS

1962 ◽  
Vol 40 (1) ◽  
pp. 1043-1050 ◽  
Author(s):  
P. W. Hochachka ◽  
J. M. Teal ◽  
M. Telford
Keyword(s):  
Citric Acid ◽  
Oxygen Uptake ◽  
Carbohydrate Metabolism ◽  
Citric Acid Cycle ◽  
The Other ◽  
Short Term ◽  
Acid Cycle

Oxygen uptake by homogenates of lobster hepatopancreas was stimulated by the addition of Embden–Meyerhof, pentose cycle, and citric acid cycle intermediates as well as xylose. Acetate-1-C14oxidation was blocked by fluoracetate and glucose-1-C14oxidation fell by 80% with iodoacetate treatment. TPN and DPN increased glucose-1-C14oxidation by 140% and 20% and acetate-1-C14oxidation by 50% and 100% respectively. Large amounts of C14enter polysaccharide following treatment with glucose-1-C14or acetate-1-C14but very little enters after treatment with the same amount of gluconate-1-C14. Gluconate and xylose oxidation occurs in mitochondria-free preparations. In short-term tests with acetate-1-C14as substrate, most of the label in glycogen is on carbons 3 and 4 and the amount in the other positions can be explained on the basis of a 5–10% participation of the pentose cycle.

ENZYMMUSTER UND PROGESTERONSYNTHESE

1967 ◽  
Vol 56 (3) ◽  
pp. 433-444 ◽  
Author(s):  
Hartmut Brandau ◽  
Karin Remmlinger ◽  
Wilfried Luh
Keyword(s):  
Citric Acid ◽  
Granulosa Cells ◽  
Citric Acid Cycle ◽  
Pentose Phosphate ◽  
Enzyme Activation ◽  
Corpora Lutea ◽  
Activity Levels ◽  
Acid Cycle ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

ABSTRACT During the maturation of follicles and corpora lutea in the rabbit ovary the activity levels of oxidoreductases of glycolysis, citric acid cycle, glycerophosphate cycle, pentose phosphate shunt as well as the Δ5,3β-hydroxy-steroid dehydrogenase were studied in granulosa cells by histochemical technique. While the oxidoreductases of the glycolysis, the citric acid cycle and glycerophosphate cycle show continuously unvaried activities a remarkable increase was found regarding the activities of NADPH2-supplying enzymes and Δ5,3β-hydroxy-steroid dehydrogenase before resp. after ovulation. According to these relations the granulosa cells of rabbit ovary cannot produce progesterone prior to 8 hours after ovulation. Furthermore, the analysis of the sequence and the functional role of enzyme activation in the granulosa cells allows some conclusions about the mechanism of gonadotrophin action influencing the metabolism of steroid hormone producing cells.

EFFECT OF SERUM GONADOTROPHIN ON DEHYDROGENASES OF THE CITRIC ACID CYCLE IN THE OVARY OF THE RAT

1963 ◽  
Vol 42 (4) ◽  
pp. 480-484 ◽  
Author(s):  
B. Eckstein ◽  
R. Landsberg
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Age Groups ◽  
Succinic Dehydrogenase ◽  
Immature Rat ◽  
Acid Cycle ◽  
Immature Rats ◽  
Rat Ovary

ABSTRACT The succinic, malic and isocitric dehydrogenases in the ovary of immature and mature, normal and serum gonadotrophin injected rats were examined. The Qo2 of these enzymes were markedly enhanced in the gonadotrophin injected rats of both age groups, except in the case of succinic dehydrogenase in the ovary of the immature rats, where a slight non-significant decrease was noted. It is concluded that in the mature rat ovary, gonadotrophin administration stimulates the activity of all the examined dehydrogenases of the citric acid cycle, whereas in the immature rat ovary, at least the isocitric- and malic dehydrogenases are thus stimulated.

Sign in / Sign up

Export Citation Format

Share Document