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Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites

Dissertation (MSc (Biochemistry))--University of Pretoria, 2024.

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Other Authors: Niemand, Jandeli
Format: Thesis
Language:English
Published: University of Pretoria 2024
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access_status_str Open Access
author2 Niemand, Jandeli
author_browse Niemand, Jandeli
author_facet Niemand, Jandeli
collection Thesis
dc_rights_str_mv © 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc (Biochemistry))--University of Pretoria, 2024.
format Thesis
id oai:repository.up.ac.za:2263/96331
institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:38:22.209Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2024
publishDateRange 2024
publishDateSort 2024
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/96331 Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites Niemand, Jandeli u17075395@tuks.co.za Birkholtz, Lyn-Marie Thomas, Jean Argyle UCTD Plasmodium Membrane potential Fluorescent dyes Potassium Dissertation (MSc (Biochemistry))--University of Pretoria, 2024. While malaria is a treatable disease caused by Plasmodium parasites, resulting in worldwide mortality. Plasmodium falciparum parasites are vulnerable to changes in intracellular ion concentrations. The parasite Na+/H+-ATPase (PfATP4) responsible for the simultaneous efflux of Na+ and the influx of H+ is targeted by chemically diverse antiplasmodial compounds, while triaminopyrimidine resistance is associated with mutations in a V-type H+-ATPase. In P. falciparum parasites, a high intracellular K+ concentration is maintained by the influx of K+ through K+ channels, against the concentration gradient due to a highly negative membrane potential. Given that K+ is the most abundant intracellular cation, it is possible that changing intracellular K+ levels would prevent parasite proliferation. Any changes in the intracellular K+ also affect the membrane potential, ultimately leading to cell death. Previous whole-cell proliferation assays showed that putative K+ channel inhibitors and ionophores inhibit proliferation, but these studies did not test the antiproliferative effects with changes in intracellular K+. We found that 250 nM DiBAC4(3) provided a high fluorescent signal in isolated asexual P. falciparum trophozoites after 30 min incubation. This condition resulted in a signal-to-noise of 119.28 and a Z’-factor of 0.83 and was used for further analysis of changes in the parasite’s membrane potential after treatment with inhibitors. APG-1 (5 μM) resulted in the highest signal-to-background ratio after 60 minutes, that also resulted in high signal-to-noise ratios (276.26) and a Z’-factor of 0.89. Therefore, the two fluorescent probes could successfully be detected in P. falciparum parasites and subsequently evaluate changes in Δψ and intracellular K+. NRF Biochemistry MSc (Biochemistry) Unrestricted Faculty of Natural and Agricultural Sciences SDG-01: No poverty SDG-03: Good health and well-being SDG-09: Industry, innovation and infrastructure 2024-06-06T09:45:41Z 2024-06-06T09:45:41Z 2024-09-07 2024-06-04 Dissertation * S2024 http://hdl.handle.net/2263/96331 DOI: https://doi.org/10.25403/UPresearchdata.25958974.v1 10.25403/UPresearchdata.25958974 en © 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Plasmodium
Membrane potential
Fluorescent dyes
Potassium
Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites
title Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites
title_full Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites
title_fullStr Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites
title_full_unstemmed Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites
title_short Development of fluorescence-based assays to determine changes in membrane potential and K+ levels in isolated Plasmodium falciparum parasites
title_sort development of fluorescence based assays to determine changes in membrane potential and k levels in isolated plasmodium falciparum parasites
topic UCTD
Plasmodium
Membrane potential
Fluorescent dyes
Potassium
url http://hdl.handle.net/2263/96331