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A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum

Bibliography: pages 107-111.

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Main Author: Ludlow, Christopher Trimble
Other Authors: Van Regenmortel, M H V
Format: Thesis
Language:English
Published: Department of Molecular and Cell Biology 2016
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access_status_str Open Access
author Ludlow, Christopher Trimble
author2 Van Regenmortel, M H V
author_browse Ludlow, Christopher Trimble
Van Regenmortel, M H V
author_facet Van Regenmortel, M H V
Ludlow, Christopher Trimble
author_sort Ludlow, Christopher Trimble
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description Bibliography: pages 107-111.
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id oai:open.uct.ac.za:11427/22333
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:33:49.949Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2016
publishDateRange 2016
publishDateSort 2016
publisher Department of Molecular and Cell Biology
publisherStr Department of Molecular and Cell Biology
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spelling oai:open.uct.ac.za:11427/22333 A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum Ludlow, Christopher Trimble Van Regenmortel, M H V Microbiology Bibliography: pages 107-111. Durham, in a review published in 1974, presented the following hypotheses concerning the factors that control amoeboid movement: (1) actin and myosin are present in all cells that exhibit amoeboid movement and, changes in the internal [Ca⁺⁺] regulate contraction, (2) filaments of actin and myosin form an intimate association with the surface membrane and depending on the local [Ca⁺⁺] , the filaments can cause the membrane to relax or become rigid, (3) Ca⁺⁺ fluxes across the external membrane (viz. efflux and influx) regulate the state of contraction in the proposed actinomyosin-surface membrane network and, (4) such Ca++ fluxes operating across the membrane manifest themselves (especially with slime mould plasmodia) as waves of adhesion running across the undersurface of a cell and aid in movement. A working hypothesis, that encompasses the ideas of Durham, is that Ca⁺⁺ entry and efflux across the external membrane control such cellular processes as extension of pseudopodia, exocytosis, endocytosis and the direction of movement (chemotactic response) of amoeboid cells. In the specific case of slime mould plasmodia, which best exemplify all of Durham's hypotheses, the simplest hypothesis to explain the control of chemotaxis is that attractants (sugars, food; organisms) cause a Ca⁺⁺ efflux across the membrane and a subsequent movement forward. Repellents would act in a reverse manner by causing Ca⁺⁺ entry. This hypothesis also allows for the existence of a Ca⁺⁺-accumulating organelle. This organelle might replace or act in concert with the proposed Ca⁺⁺ fluxes across the external membrane. The investigations reported in this thesis were devised to examine experimentally this hypothesis. 2016-10-27T14:24:57Z 2016-10-27T14:24:57Z 1977 Master Thesis Masters MSc http://hdl.handle.net/11427/22333 eng application/pdf Department of Molecular and Cell Biology Faculty of Science University of Cape Town
spellingShingle Microbiology
Ludlow, Christopher Trimble
A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum
thesis_degree_str Master's
title A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum
title_full A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum
title_fullStr A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum
title_full_unstemmed A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum
title_short A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum
title_sort proposed role for the ca ion in the chemotactic response of physarum polycephalum
topic Microbiology
url http://hdl.handle.net/11427/22333
work_keys_str_mv AT ludlowchristophertrimble aproposedroleforthecaioninthechemotacticresponseofphysarumpolycephalum
AT ludlowchristophertrimble proposedroleforthecaioninthechemotacticresponseofphysarumpolycephalum