The extraordinary mitochondrion and unusual citric acid cycle in Trypanosoma brucei

2005 ◽  
Vol 33 (5) ◽  
pp. 967 ◽  
Author(s):  
F.R. Opperdoes ◽  
J.J. van Hellemond ◽  
A.G.M. Tielens
Keyword(s):  
Citric Acid ◽  
Trypanosoma Brucei ◽  
Citric Acid Cycle ◽  
Acid Cycle

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.

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

Clustering of sequential enzymes in the glycolytic pathway and the citric acid cycle

1990 ◽  
Vol 43 (4) ◽  
pp. 297-306 ◽  
Author(s):  
Sonia Beeckmans ◽  
Edilbert Van Driessche ◽  
Louis Kanarek
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Glycolytic Pathway ◽  
Acid Cycle
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