Probing the Metabolic Network in Bloodstream-Form Trypanosoma brucei Using Untargeted Metabolomics with Stable Isotope Labelled Glucose
Journal article, 2015
Metabolomics coupled with heavy-atom isotope-labelled glucose has been used to probe the metabolic pathways active in cultured bloodstream form trypomastigotes of Trypanosoma brucei, a parasite responsible for human African trypanosomiasis. Glucose enters many branches of metabolism beyond glycolysis, which has been widely held to be the sole route of glucose metabolism. Whilst pyruvate is the major end-product of glucose catabolism, its transamination product, alanine, is also produced in significant quantities. The oxidative branch of the pentose phosphate pathway is operative, although the non-oxidative branch is not. Ribose 5-phosphate generated through this pathway distributes widely into nucleotide synthesis and other branches of metabolism. Acetate, derived from glucose, is found associated with a range of acetylated amino acids and, to a lesser extent, fatty acids; while labelled glycerol is found in many glycerophospholipids. Glucose also enters inositol and several sugar nucleotides that serve as precursors to macromolecule biosynthesis. Although a Krebs cycle is not operative, malate, fumarate and succinate, primarily labelled in three carbons, were present, indicating an origin from phosphoenolpyruvate via oxaloacetate. Interestingly, the enzyme responsible for conversion of phosphoenolpyruvate to oxaloacetate, phosphoenolpyruvate carboxykinase, was shown to be essential to the bloodstream form trypanosomes, as demonstrated by the lethal phenotype induced by RNAi-mediated downregulation of its expression. In addition, glucose derivatives enter pyrimidine biosynthesis via oxaloacetate as a precursor to aspartate and orotate.
Author
D. J. Creek
Monash University
M. Mazet
Centre de Resonance Magnetique des Systemes Biologiques
F. Achcar
Wellcome Trust Centre for Molecular Parasitology
J. Anderson
University of Glasgow
D. H. Kim
University of Nottingham
R. Kamour
University of Tripoli
P. Morand
University of California
Centre de Resonance Magnetique des Systemes Biologiques
Y. Millerioux
Centre de Resonance Magnetique des Systemes Biologiques
M. Biran
Centre de Resonance Magnetique des Systemes Biologiques
Eduard Kerkhoven
Chalmers, Biology and Biological Engineering, Systems and Synthetic Biology
A. Chokkathukalam
University of Glasgow
S. K. Weidt
University of Glasgow
K. E. V. Burgess
University of Glasgow
R. Breitling
University of Manchester
D. G. Watson
University of Strathclyde
F. Bringaud
Centre de Resonance Magnetique des Systemes Biologiques
M. P. Barrett
Wellcome Trust Centre for Molecular Parasitology
University of Glasgow
PLoS Pathogens
1553-7366 (ISSN) 1553-7374 (eISSN)
Vol. 11 3 1-25 e1004689Subject Categories
Biological Systematics
DOI
10.1371/journal.ppat.1004689