ENERGY METABOLISM OF PHYCOMYCES BLAKESLEEANUS THE CITRIC ACID CYCLE AND ASSOCIATED AMINO ACIDS

1966 ◽  
Vol 12 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Edwin C. Gangloff
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Energy Metabolism ◽  
Organic Acids ◽  
High Activity ◽  
Citric Acid Cycle ◽  
Specific Activity ◽  
Nitrogen Compounds ◽  
Phycomyces Blakesleeanus ◽  
Acid Cycle

All of the intermediates of the citric acid cycle are shown to be present in the mycelium of 6-day cultures of P. blakesleeanus grown on glucose and on ammonium sulfate, and fed non-radioactive acetate on the fourth and fifth days and acetate-1-C14 on the fifth day of incubation.The concentration of organic acids and certain amino acids, and their specific activity is reported. The high activity of the latter is thought to indicate the presence of a highly labeled pool of nitrogen compounds persisting from the early anabolic reactions after acetate-1-C14 administration.

Lactate Reverses Insulin-Induced Hypoglycemic Stupor in Suckling—Weanling Mice: Biochemical Correlates in Blood, Liver, and Brain

1983 ◽  
Vol 3 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Jean Holowach Thurston ◽  
Richard E. Hauhart ◽  
James A. Schiro
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Energy Metabolism ◽  
Citric Acid Cycle ◽  
Plasma Lactate ◽  
Brain Glucose ◽  
Acid Cycle ◽  
Glucose Levels ◽  
Glycolytic Intermediates ◽  
Lactate Levels

The recovery of weanling mice from insulin-induced hypoglycemic stupor–coma after injection of sodium -l(+)-lactate (18 mmol/kg) was as rapid (10 min) as in litter-mates treated with glucose (9 mmol/kg). Stimulated by this dramatic action, we studied the effects of lactate injection on brain carbohydrate and energy metabolism in normal and hypoglycemic mice; blood and liver tissue were also studied. Ten minutes after lactate injection in normal mice, plasma lactate levels increased by 15 mmol/L; plasma glucose levels were unchanged, but the β-hydroxybutyrate concentration fell 59%. In the brains of these animals, glucose levels increased 2.3-fold, and there were significant increases in brain glycogen (10%), glucose-6-phosphate (27%), lactate (68%), pyruvate (37%), citrate (12%), and malate (19%); the increase in α-ketoglutarate (32%) was not significant. Lactate injection reduced the cerebral glucose-use rate 40%. These changes were not due to lactate-induced increases in blood [HCO−3] and pH (examined by injection of 15 mmol/kg sodium bicarbonate). Although lactate injection of hypoglycemic mice doubled levels of glucose in plasma and brain (not significant) and most of the cerebral glycolytic intermediates, values were far below normal (still in the range seen in hypoglycemic animals). By contrast, citrate and α-ketoglutarate levels returned to normal; the large increase in malate was not significant. Reduced glutamate levels increased to normal, and elevated aspartate levels fell below normal. Thus, recovery from hypoglycemic stupor does not necessarily depend on normal levels of plasma and/or brain glucose (or glycolytic intermediates). Near normal levels of the Krebs citric acid cycle intermediates suggest that changes in these metabolites, amino acids, or derived substrates relate to the dramatic recovery of hypoglycemic mice after lactate injection.

Effect of cyclic AMP on catabolite-repressed zoosporangial formation in Phytophthora capsici

1977 ◽  
Vol 55 (7) ◽  
pp. 840-843 ◽  
Author(s):  
M. Yoshikawa ◽  
H. Masago
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Cyclic Amp ◽  
Catabolite Repression ◽  
Citric Acid Cycle ◽  
Phytophthora Capsici ◽  
Antimycin A ◽  
Acid Cycle

Zoosporangial formation in Phytophthora capsici was sensitively inhibited by glucose and other catabolites including sugars, citric acid cycle acids, and amino acids, but was only slightly inhibited by 3-O-methylglucose and 2-deoxyglucose and by other seemingly weak catabolites. The inhibitions were specifically prevented by cyclic AMP among the various related nucleotides evaluated. The reversing effect by cyclic AMP was observed only on zoosporangial formation that was partially repressed by catabolites, but the completely repressed zoosporangial formation could not be reversed by cyclic AMP. Furthermore, cyclic AMP failed in reversing zoosporangial formation that was inhibited by antibiotics such as antimycin A and cycloheximide. The results suggested that the initiation of zoosporangial formation in the fungus is under the control of catabolite repression that is mediated by cyclic AMP.

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.

The extraordinary mitochondrion and unusual citric acid cycle in Trypanosoma brucei

2005 ◽  
Vol 33 (5) ◽  
pp. 967-971 ◽  
Author(s):  
J.J. van Hellemond ◽  
F.R. Opperdoes ◽  
A.G.M. Tielens
Keyword(s):  
Citric Acid ◽  
Energy Metabolism ◽  
Trypanosoma Brucei ◽  
Citric Acid Cycle ◽  
Clinical Importance ◽  
African Trypanosomes ◽  
Acid Cycle ◽  
Fermentative Metabolism ◽  
Influence Of Substrate ◽  
Citric Acid Cycle Enzymes

African trypanosomes are parasitic protozoa that cause sleeping sickness and nagana. Trypanosomes are not only of scientific interest because of their clinical importance, but also because these protozoa contain several very unusual biological features, such as their specially adapted mitochondrion and the compartmentalization of glycolytic enzymes in glycosomes. The energy metabolism of Trypanosoma brucei differs significantly from that of their hosts and changes drastically during the life cycle. Despite the presence of all citric acid cycle enzymes in procyclic insect-stage T. brucei, citric acid cycle activity is not used for energy generation. Recent investigations on the influence of substrate availability on the type of energy metabolism showed that absence of glycolytic substrates did not induce a shift from a fermentative metabolism to complete oxidation of substrates. Apparently, insect-stage T. brucei use parts of the citric acid cycle for other purposes than for complete degradation of mitochondrial substrates. Parts of the cycle are suggested to be used for (i) transport of acetyl-CoA units from the mitochondrion to the cytosol for the biosynthesis of fatty acids, (ii) degradation of proline and glutamate to succinate, (iii) generation of malate, which can then be used for gluconeogenesis. Therefore the citric acid cycle in trypanosomes does not function as a cycle.

Oxidative metabolism of bovine spermatozoa

1968 ◽  
Vol 46 (10) ◽  
pp. 1331-1332
Author(s):  
J. F. Masken ◽  
M. L. Hopwood
Keyword(s):  
Oxygen Consumption ◽  
Citric Acid ◽  
Melting Point ◽  
Oxidative Metabolism ◽  
Phosphate Buffer ◽  
Citric Acid Cycle ◽  
Specific Activity ◽  
Acid Cycle ◽  
Bovine Sperm ◽  
Bovine Spermatozoa

Suspensions of washed bovine sperm (phosphate buffer, pH 7.4) were incubated at 37 °C for 1 h with pyruvate-3-14C and in some cases, with oxaloacetate. Oxygen consumption and 14CO2 evolution were measured. Radioactive citrate, malate, fumarate, α-ketoglutarate, and oxaloacetate were found following incubation. The latter two compounds were positively identified by melting-point and specific-activity determinations of their 2,4-dinitrophenylhydrazone derivatives. The results indicate citric acid cycle activity in bull sperm. Oxygen consumption and the evolution of 14CO2 from pyruvate-3-14C tended to decline when oxaloacetate was added to the sperm suspensions.

scholarly journals Biosynthesis of food constituents: Amino acids: 1. The glutamic acid and aspartic acid groups – a review

2011 ◽  
Vol 24 (No. 1) ◽  
pp. 1-10
Author(s):  
J. Velíšek ◽  
K. Cejpek
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Citric Acid Cycle ◽  
Acid Group ◽  
Review Article ◽  
Acid Cycle ◽  
Oxaloacetic Acid ◽  
Reaction Schemes

This review article gives a survey of principal pathways that lead to the biosynthesis of the proteinogenic amino acids of the glutamic acid group (glutamic acid, glutamine, proline, arginine) and aspartic acid group (aspartic acid, asparagine, threonine, methionine, lysine, isoleucine) starting with oxaloacetic acid from the citric acid cycle. There is an extensive use of reaction schemes, sequences, and mechanisms with the enzymes involved and detailed explanations using sound chemical principles and mechanisms.

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