Format

Send to

Choose Destination
Int J Parasitol. 2006 Feb;36(2):229-36. Epub 2005 Nov 21.

Biosynthesis and uptake of thiamine (vitamin B1) in bloodstream form Trypanosoma brucei brucei and interference of the vitamin with melarsen oxide activity.

Author information

1
Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland.

Abstract

Bloodstream forms of Trypanosoma brucei brucei were cultivated in the presence and absence of thiamine (vitamin B1) and pyridoxine (vitamin B6). The vitamins do not change growth behaviour, indicating that Trypanosoma brucei is prototrophic for the two vitamins even though in silico no bona-fide thiamine-biosynthetic genes could be identified in the T. brucei genome. Intracellularly, thiamine is mainly present in its diphosphate form. We were unable to detect significant uptake of [3H]thiamine and structural thiamine analogues such as pyrithiamine, oxithiamine and amprolium were not toxic for the bloodstream forms of T. brucei, indicating that the organism does not have an efficient uptake system for thiamine and its analogues. We have previously shown that, in the fission yeast Saccharomyces pombe, the toxicity of melarsen oxide, the pharmacologically active derivative of the frontline sleeping sickness drug melarsoprol, is abolished by thiamine and the drug is taken up by a thiamine-regulated membrane protein which is responsible for the utilization of thiamine. We show here that thiamine also has weak effects on melarsen oxide-induced growth inhibition and lysis in T. brucei. These effects were consistent with a low affinity of thiamine for the P2 adenosine transporter that is responsible for uptake of melaminophenyl arsenicals in African trypanosomes.

PMID:
16375907
DOI:
10.1016/j.ijpara.2005.10.003
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center