Affiliation:
1. Institute of Biomedical and Life Sciences, Division of Infection and Immunity, University of Glasgow, Glasgow G12 8QQ, United Kingdom
Abstract
ABSTRACT
Resistance to diminazene aceturate (Berenil) is a severe problem in the control of African trypanosomiasis in domestic animals. It has been speculated that resistance may be the result of reduced diminazene uptake by the parasite. We describe here the mechanisms by which [
3
H]diminazene is transported by
Trypanosoma brucei brucei
bloodstream forms. Diminazene was rapidly accumulated through a single transporter, with a
K
m
of 0.45 ± 0.11 μM, which was dose dependently inhibited by pentamidine and adenosine. The
K
i
values for these inhibitors were consistent with this transporter being the P2/TbAT1 adenosine transporter. Yeast expressing
TbAT1
acquired the ability to take up [
3
H]diminazene and [
3
H]pentamidine.
TbAT1
-null mutants had lost almost all capacity for [
3
H]diminazene transport. However, this cell line still displayed a small but detectable rate of [
3
H]diminazene accumulation, in a nonsaturable manner. We conclude that TbAT1 mediates [
3
H]diminazene transport almost exclusively and that this explains the observed diminazene resistance phenotypes of
TbAT1
-null mutants and field isolates.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
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