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Fluidity-dependent Mg2(+)-ATPase activity in membranes from Leishmania donovani promastigotes.

ABSTRACT: The state of the lipid phase of the membrane plays a key role in the exposure of various receptors, antigens and enzymes on the membrane surface. The fluidity of membranes of Leishmania donovani promastigotes was monitored by two independent methods, i.e. influx of sterol from liposomes and removal of phospholipids by treatment with phospholipase C. The altered sterol/phospholipid ratio, in both cases, provided evidence that the activity of the functionally important membrane-bound enzyme Mg2(+)-ATPase is modulated by the state of the lipid phase of the membrane.

SUBMITTER: Dutta M

PROVIDER: S-EPMC1133723 | biostudies-other | 1990 Feb

REPOSITORIES: biostudies-other

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RNA editing and mitochondrial activity in promastigotes and amastigotes of Leishmania donovani.

Project description:Kinetoplast maxicircle DNA sequence organisation was investigated in Leishmania donovani, strain 1S LdBob. Gene arrangement in the coding (conserved) region of the maxicircle is collinear with that of most trypanosomatids, with individual genes showing 80-90% nucleotide identity to Leishmania tarentolae, strain UC. The notable exception was an integration of a full-size minicircle sequence in the ND1 gene coding region found in L. donovani. Editing patterns of the mitochondrial mRNAs investigated also followed L. tarentolae UC patterns, including productive editing of the components of respiratory complexes III-V, and ribosomal protein S12 (RPS12), as well as the lack of productive editing in five out of six pan-edited cryptogenes (ND3, ND8, ND9, G3, G4) found in these species. Several guide RNAs for the editing events were localised in minicircles and maxicircles in the locations that are conserved between the species. Mitochondrial activity, including rates of oxygen consumption, the presence and the levels of respiratory complexes and their individual subunits and the steady-state levels of several mitochondrial-encoded mRNAs were essentially the same in axenically grown amastigotes and in promastigotes of L. donovani. However, some modulation of mitochondrial activity between these developmental stages was suggested by the finding of an amastigote-specific component in complex IV, a down-regulation of mitochondrial RNA-binding proteins (MRP) and MRP-associated protein (MRP-AP) in amastigotes, and by variations in the levels of RPS12, ND3, ND9, G3 and G4 pre-edited transcripts.

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Pentamidine uptake in Leishmania donovani and Leishmania amazonensis promastigotes and axenic amastigotes.

Project description:A transport system for pentamidine in Leishmania donovani and Leishmania amazonensis promastigotes and axenic amastigotes has been identified and characterized. Pentamidine is not metabolized by these parasites. Its uptake process is saturable, carrier-mediated and energy-dependent. This drug does not inhibit purine or pyrimidine uptake, whereas it inhibits uptake of several amino acids non-competitively and that of putrescine and spermidine competitively. The results suggest that pentamidine shares polyamine-carrier systems in these parasites.

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Project description:In this study, we examined the transcriptome of Leishmania donovani promastigotes and axenic amastigotes to identify differentially regulated mRNAs utilizing the serial analysis of gene expression Keywords: stage differentiation; axenic amastigotes

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| S-EPMC1136440 | biostudies-other

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Arginase Is Essential for Survival of Leishmania donovani Promastigotes but Not Intracellular Amastigotes.

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Comparison of gene expression of miltefosine responsive Vs miltefosine unresponsive Leishmania donovani promastigotes

Project description:The current study aims to study change in gene expression profile of miltefosine resistance L. donovani with respect to miltefosine responsive L. donovani.

2013-08-05 | GSE45496 | GEO

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