Glucose Metabolism in the Caecum of the Marine Borer Bankia setacea

1968 ◽  
Vol 25 (5) ◽  
pp. 853-862 ◽  
Author(s):  
D. Liu ◽  
P. M. Townsley
Keyword(s):  
Citric Acid ◽  
Glucose Metabolism ◽  
Soluble Protein ◽  
Citric Acid Cycle ◽  
Digestive Organ ◽  
Acid Cycle ◽  
Wood Borer ◽  
Pentose Pathway

The degradation of uniformly labelled glucose-C14 was followed in the caeca preparations of the marine wood borer Bankia setacea (Tryon). This digestive organ was found to contain large quantities of soluble protein. Various accumulating intermediates were isolated, indicating the presence of enzymes typical of the Embden–Meyerhof pathway, the pentose pathway, the citric acid cycle, and the non-triose pathway. The presence of wood in the caeca may be required for the synthesis of glutamic and aspartic acids within the caeca. Approximately 10% of the added glucose was found in an unidentified, unstable, electronegative compound called glucose-X. The function of this compound is unknown.

Enzymes of Glucose Metabolism in the Caecum of the Marine Borer Bankia setacea

1970 ◽  
Vol 27 (6) ◽  
pp. 1141-1146 ◽  
Author(s):  
D. L. Liu ◽  
C. C. Walden
Keyword(s):  
Citric Acid ◽  
Glucose Metabolism ◽  
Enzyme Activities ◽  
Citric Acid Cycle ◽  
Acid Cycle ◽  
Modified Embden Meyerhof Pathway

The caecum of the marine borer Bankia setacea was found to contain the enzymes for a modified Embden–Meyerhof pathway, a pentose cycle, and a complete citric acid cycle. The pathways are linked to the digestion of cellulose by the enzyme cellobiase. Significant numbers of bacteria were not detected in the caecum of the borer. Enzyme activities in the citric acid cycle indicate a biosynthesis role for the caecum.

scholarly journals Effects of starvation on the maximal activities of some glycolytic and citric acid-cycle enzymes and glutaminase in mucosa of the small intestine of the rat

1982 ◽  
Vol 206 (1) ◽  
pp. 169-172 ◽  
Author(s):  
Leszek Budohoski ◽  
R. A. John Challis ◽  
Eric A. Newsholme
Keyword(s):  
Small Intestine ◽  
Citric Acid ◽  
Glucose Metabolism ◽  
Citric Acid Cycle ◽  
Fructose Bisphosphatase ◽  
Acid Cycle ◽  
Absorptive Cells ◽  
Citric Acid Cycle Enzymes

Starvation decreases activities of some glycolytic and citric acid-cycle enzymes, and increases those of glucose 6-phosphatase and fructose bisphosphatase, whereas that of glutaminase is unchanged. These findings may be of significance for the control of glucose metabolism in the absorptive cells of the intestine.

scholarly journals Glutamine and glucose metabolism during thymocyte proliferation. Pathways of glutamine and glutamate metabolism

1985 ◽  
Vol 228 (2) ◽  
pp. 353-361 ◽  
Author(s):  
K Brand
Keyword(s):  
Citric Acid ◽  
Glucose Metabolism ◽  
Glutamate Dehydrogenase ◽  
Aspartate Aminotransferase ◽  
Citric Acid Cycle ◽  
Glutamine Metabolism ◽  
Resting Cells ◽  
Glutamate Metabolism ◽  
Proliferating Cells ◽  
Acid Cycle

Energy metabolism in proliferating cultured rat thymocytes was compared with that of freshly prepared non-proliferating resting cells. Cultured rat thymocytes enter a proliferative cycle after stimulation by concanavalin A and Lymphocult T (interleukin-2), with maximal rates of DNA synthesis at 60 h. Compared with incubated resting thymocytes, glucose metabolism by incubated proliferating thymocytes was 53-fold increased; 90% of the amount of glucose utilized was converted into lactate, whereas resting cells metabolized only 56% to lactate. However, the latter oxidized 27% of glucose to CO2, as opposed to 1.1% by the proliferating cells. Activities of hexokinase, 6-phosphofructokinase, pyruvate kinase and aldolase in proliferating thymocytes were increased 12-, 17-, 30- and 24-fold respectively, whereas the rate of pyruvate oxidation was enhanced only 3-fold. The relatively low capacity of pyruvate degradation in proliferating thymocytes might be the reason for almost complete conversion of glucose into lactate by these cells. Glutamine utilization by rat thymocytes was 8-fold increased during proliferation. The major end products of glutamine metabolism are glutamate, aspartate, CO2 and ammonia. A complete recovery of glutamine carbon and nitrogen in the products was obtained. The amount of glutamate formed by phosphate-dependent glutaminase which entered the citric acid cycle was enhanced 5-fold in the proliferating cells: 76% was converted into 2-oxoglutarate by aspartate aminotransferase, present in high activity, and the remaining 24% by glutamate dehydrogenase. With resting cells the same percentages were obtained (75 and 25). Maximal activities of glutaminase, glutamate dehydrogenase and aspartate aminotransferase were increased 3-, 12- and 6-fold respectively in proliferating cells; 32% of the glutamate metabolized in the citric acid cycle was recovered in CO2 and 61% in aspartate. In resting cells this proportion was 41% and 59% and in mitogen-stimulated cells 39% and 65% respectively. Addition of glucose (4 mM) or malate (2 mM) strongly decreased the rates of glutamine utilization and glutamate conversion into 2-oxoglutarate by proliferating thymocytes and also affected the pathways of further glutamate metabolism. Addition of 2 mM-pyruvate did not alter the rate of glutamine utilization by proliferating thymocytes, but decreased the rate of metabolism beyond the stage of glutamate significantly. Formation of acetyl-CoA in the presence of pyruvate might explain the relatively enhanced oxidation of glutamate to CO2 (56%) by proliferating thymocytes.

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.

scholarly journals CHROMATOGRAPHIC DETERMINATION OF THE ACIDS OF THE CITRIC ACID CYCLE IN TISSUES

1951 ◽  
Vol 193 (1) ◽  
pp. 277-283 ◽  
Author(s):  
CharlesE. Frohman ◽  
JamesM. Orten ◽  
ArthurH. Smith
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Chromatographic Determination ◽  
Acid Cycle
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