In:
Journal of Medical Microbiology, Microbiology Society, Vol. 56, No. 5 ( 2007-05-01), p. 629-636
Abstract:
Leishmaniasis constitutes a complex of diseases with clinical and epidemiological diversity and includes visceral leishmaniasis, a disease that is fatal when left untreated. In earlier studies, the authors reported that Aloe vera leaf exudate (AVL) is a potent antileishmanial agent effective in promastigotes of Leishmania braziliensis , Leishmania mexicana , Leishmania tropica , Leishmania major and Leishmania infantum and also in axenic amastigotes of Leishmania donovani . In the present study, it has been demonstrated that, in promastigotes of L. donovani (IC 50 =110 μg ml −1 ), AVL mediates this leishmanicidal effect by triggering a programmed cell death. Incubation of promastigotes with AVL caused translocation of phosphatidylserine to the outer leaflet of the plasma membrane as measured by annexin V binding, which was accompanied by loss of mitochondrial membrane potential, release of cytochrome c into the cytosol and concomitant nuclear alterations that included chromatin condensation, deoxynucleotidyltransferase-mediated dUTP end labelling and DNA laddering. As this AVL-induced leishmanicidal effect could not be inhibited by protease inhibitors including Z-Val-Ala- dl -Asp (methoxy)-fluoromethylketone, a broad-spectrum caspase inhibitor, non-involvement of caspases and major proteases was suggested. Additionally, AVL treatment caused no increase in cytosolic Ca 2+ or generation of reactive oxygen species, indicating that although promastigote death was induced by an apoptotic-like mechanism similar to metazoan apoptosis, the pathways of induction and/or execution differed at the molecular level.
Type of Medium:
Online Resource
ISSN:
0022-2615
,
1473-5644
DOI:
10.1099/jmm.0.47039-0
Language:
English
Publisher:
Microbiology Society
Publication Date:
2007
detail.hit.zdb_id:
2083944-3
SSG:
12
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