Trypanosoma brucei, metabolism

Blattner, J. Helfert, S. Michels, P. Clayton, C. Compartmentation of phosphoglycerate kinase in Trypanosoma brucei plays a critical role in parasite energy metabolism. Proc. Natl. Acad. Sci. USA, 95, 11596-11600 (1998)... 

Rivibre L, van Weelden SWH, Glass P, Vegh P, Coustou V, Biran M, van Hellemond JJ, Bringaud F, Tielens AGM, Boshart M (2004) Acetyhsuccinate CoA-transferase in procyclic Trypanosoma brucei - gene identification and role in carbohydrate metabolism. J Biol Chem 279 45337-45346... 

Misek, D.E. and Saltiel, A.R. An inositol phosphate glycan derived from a Trypanosoma brucei glycosyl-phosphatidylinositol mimics some of the metabolic actions of insulin. J. Biol. Chem., 1992, 267, 16266-16273. 

A very simplified example is shown in Figure 4.1, in which the different snbstances involved are jnst represented by gray balls, with lines between them representing chemical reactions in a real chart for teaching metabolism the names and other details wonld be shown explicitly. This diagram may look very complicated, and yon may suspect that I have chosen an unnecessarily complicated example, but in fact the reverse is true the organism represented, the form of the parasite Trypanosoma brucei that exists in the bloodstream of people infected with African sleeping sickness, has possibly the simplest... 

Fig. 4.1 Simplified representation of the main metabolic activity of the form of the parasite Trypanosoma brucei found in the bloodstream. The different degrees of shading distinguish the four different compartments in the system, including the blood of the host, which supplies the glucose and inorganic phosphate needed by the parasite for its metabohsm, and receives the pyruvate and glycerol that it excretes. The shaded circles represent the different metabolites, connected by hues to indicate enzyme-catalyzed reactions...

Callens, M., Kuntz, D. A. and Opperdoes, F. R. (1991) Characterization of pyruvate kinase of Trypanosoma brucei and its role in the regulation of carbohydrate metabolism. Mol. Biochem. Parasitol. 47 19 30. 

Van Schaftingen, E., Opperdoes, F. R. and Hers, H.-G. (1987) Effects of various metabolic conditions of the trivalent arsenical melarsen oxide on the intracellular levels of fructose 2,6-bisphosphate and of glycolytic intermediates in Trypanosoma brucei. Eur. J. Biochem. 166 653-661. 

Trypanosoma brucei complex. Unlike Leishmania and T. cruzi, the mammalian (bloodstream) forms of the T. brucei complex are much easier to obtain. Thus more is known on how purine metabolism in the insect (procyclic) forms compares to that of mammalian bloodstream forms. 

Trypanosoma brucei complex. African trypanosomes of the Trypanosoma brucei complex metabolize pyrimidines in a manner similar to that of Leishmania and T. cruzi (Fig. 6.17). All six enzyme activities for the synthesis of UMP were detected in homogenates of blood trypomastigotes of T.b. brucei (87). In addition, uracil PRTase, cytidine deaminase, and pyrimidine cleavage activities have been detected in cell-free homogenates no uridine kinase activity was detected (94). 

Fish, W. R., Marr, J. J. and Berens, R. L. (1982) Purine metabolism in Trypanosoma brucei gambiense. Biochim. Biophys. Acta 714 422-428. 

Henderson, G., Fairlamb, A. H. and Cerami, A. (1987) Trypanothione dependent peroxide metabolism in Crithidia fasciculata and Trypanosoma brucei. Mol. Biochem. Parasitol. 24 39-45. 

Gruenberg, J., Sharma, P. R. and Deshusses, J. (1978) D-glucose transport in Trypanosoma brucei. D-glucose transport is the rate-limiting step of its metabolism. Eur. J. Biochem. 89 461-469. 

Ter Kuile, B. H. and Opperdoes, F. R. (1992) Mutual adjustment of glucose uptake and metabolism in Trypanosoma brucei grown in a chemostat. J. Bacterial. 174 1273-1279. 

Wiemer EA, Midiels PA, Opperdoes FR. The inhibidon of pyruvate transport across the plasma membrane of the bloodstream form of Trypanosoma brucei and its metabolic implicadons. Biochem J 1995 312(Pt 2) 479-484. 

HPPR-MP can compete favorably with the normal substrate. The enzym-ological data are consistent with the metabolic studies which show that a large concentration of HPPR-MP (1-2 mM) is found within the cell APPR-MP is formed very slowly and in concentrations about one-tenth that of its precursor. The rate-limiting step is the formation of succino-APPR-MP by the adenylosuccinate synthetase. This conversion does not occur in mammalian tissues. The same metabolic sequences have been shown to exist in the intracellular parasitic form of L. donovani, in the vitro culture form, the blood stream and intracellular forms of Trypanosoma cruzi >7 the causative agent of American trypanosomiasis, and in the African trypanosomes T. brucei and rhodesiense. ... 

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