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

 

Show simple item record

dc.contributor.advisor Van Regenmortel, M H V en_ZA
dc.contributor.author Ludlow, Christopher Trimble en_ZA
dc.date.accessioned 2016-10-27T14:24:57Z
dc.date.available 2016-10-27T14:24:57Z
dc.date.issued 1977 en_ZA
dc.identifier.citation Ludlow, C. 1977. A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/22333
dc.description Bibliography: pages 107-111. en_ZA
dc.description.abstract 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. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Microbiology en_ZA
dc.title A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Molecular and Cell Biology en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Ludlow, C. T. (1977). <i>A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/22333 en_ZA
dc.identifier.chicagocitation Ludlow, Christopher Trimble. <i>"A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1977. http://hdl.handle.net/11427/22333 en_ZA
dc.identifier.vancouvercitation Ludlow CT. A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1977 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22333 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Ludlow, Christopher Trimble AB - 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. DA - 1977 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1977 T1 - A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum TI - A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum UR - http://hdl.handle.net/11427/22333 ER - en_ZA


Files in this item

This item appears in the following Collection(s)

Show simple item record