A novel Sucrose/H+ Symport System and an Intracellular Sucrase in Leishmania Donovani.
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
A novel Sucrose/H+ Symport System and an Intracellular Sucrase in Leishmania Donovani.
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| Creator |
Singh, Arpita
Mandal, Debjani |
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| Subject |
Infectious Diseases and Immunology
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| Description |
The flagellated form of pathogenic parasitic protozoa Leishmania, resides in the alimentary tract of its
sandfly vector, where sucrose serves as a major nutrient source. In this study we report the presence
of a sucrose transport system in Leishmania donovani promastigotes. The kinetics of sucrose uptake in
promastigotes are biphasic in nature with both high affinity Km (Km of �75 lM) and low affinity Km
(Km � 1.38 mM) components. By contrast the virulent amastigotes take up sucrose via a low affinity process
with a Km of 2.5 mM. The transport of sucrose into promastigotes leads to rapid intracellular acidification,
as indicated by changes in the fluorescence of the pH indicator 20,70-bis-(2-carboxyethyl)-5-(6)
Carboxyfluorescein (BCECF). In experiments with right side-out plasma membrane vesicles derived from
L. donovani promastigotes, an artificial pH gradient was able to drive the active accumulation of sucrose.
These data are consistent with the operation of a H+-sucrose symporter. The symporter was shown to be
independent of Na+ and to be insensitive to cytochalasin B, to the flavonoid phloretin and to the Na+/K+
ATPase inhibitor ouabain. However, the protonophore carbonylcyanide P- (trifluromethoxy) phenylhydrazone
(FCCP) and a number of thiol reagents caused significant inhibition of sucrose uptake. Evidence
was also obtained for the presence of a stable intracellular pool of the sucrose splitting enzyme, sucrase,
in promastigote stage parasites. The results are consistent with the hypothesis that L. donovani promastigotes
take up sucrose via a novel H+–sucrose symport system and that, on entering the cell, the
sucrose is hydrolysed to its component monosaccharides by an intracellular sucrase, thereby providing
an energy source for the parasites
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| Publisher |
Elsevier
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| Date |
2011
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/1274/1/INTERNATIONAL_JOURNAL_FOR_PARASITOLOGY___41(_8)_817%2D826;2011[71].pdf
Singh, Arpita and Mandal, Debjani (2011) A novel Sucrose/H+ Symport System and an Intracellular Sucrase in Leishmania Donovani. International Journal for Parasitology, 41 (8). pp. 817-826. |
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| Relation |
http://dx.doi.org/10.1016/j.ijpara.2011.03.004
http://www.eprints.iicb.res.in/1274/ |
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