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

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dc.contributor.advisorVan Regenmortel, M H Ven_ZA
dc.contributor.authorLudlow, Christopher Trimbleen_ZA
dc.date.accessioned2016-10-27T14:24:57Z
dc.date.available2016-10-27T14:24:57Z
dc.date.issued1977en_ZA
dc.descriptionBibliography: pages 107-111.en_ZA
dc.description.abstractDurham, 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.identifier.apacitationLudlow, 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/11427/22333en_ZA
dc.identifier.chicagocitationLudlow, 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/11427/22333en_ZA
dc.identifier.citationLudlow, C. 1977. A proposed role for the Ca ion in the chemotactic response of Physarum polycephalum. University of Cape Town.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
dc.identifier.urihttp://hdl.handle.net/11427/22333
dc.identifier.vancouvercitationLudlow 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/11427/22333en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Molecular and Cell Biologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMicrobiologyen_ZA
dc.titleA proposed role for the Ca ion in the chemotactic response of Physarum polycephalumen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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