Dynamics of actin filaments in an actin-myosin motility assay

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dc.contributor.advisorMuller-Nedebock, Kristian K. en_ZA
dc.contributor.advisorKriel, J. N.en_ZA
dc.contributor.authorSaffer, Oliviaen_ZA
dc.contributor.otherStellenbosch University. Faculty of Science. Dept. of Physics.en_ZA
dc.date.accessioned2023-02-03T11:48:46Z
dc.date.accessioned2023-05-18T06:57:32Z
dc.date.available2023-02-03T11:48:46Z
dc.date.available2023-05-18T06:57:32Z
dc.date.issued2023-03
dc.descriptionThesis (MSc)--Stellenbosch University, 2023. en_ZA
dc.description.abstractENGLISH ABSTRACT: Actin filaments form important parts of biological cells. Actin filaments frequently interact with myosin motors. In particular, actin filaments and myosin motors are responsible for muscle contraction in animal cells: the myosin motors attach to the actin filaments and contract, causing the filaments in the muscle to slide over each other. One way to study muscle contraction is to use experiments known as actin-myosin motility assays. This is the system we strive to model and understand in this thesis. However, there is also a broader interest in these sort of systems, since the actin-myosin motility assay is an example of an active system. After setting up our model mathematically, we begin by investigating the dynamics of a single actin filament in a motility assay by using a Langevin equation. From there, we move to including the effects of other filaments. This is achieved using hydrodynamic considerations. In order to move to a fuller picture of the dynamics of multiple filaments in a dense system, we turn to the Martin-Siggia-Rose formalism and a systematic approximation scheme known as the Random Phase Approximation. Throughout our exploration of this system, we look to derive experimentally-measurable correlation functions. While we do this, we also identify intrinsic length and time scales.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Aktienfilamente vorm belangrike dele van biologiese selle. Aktienfilamente is gereeld met miosienmotors in wisselwerking. Aktienfilamente en miosienmotors is veral verantwoordelik vir spiersametrekking in dierselle: die miosienmotors heg aan die aktienfilamente en trek saam, en veroorsaak daardeur dat die filamente in die spier oor mekaar gly. Een manier om spiersametrekking te bestudeer is deur middel van eksperimente bekend as aktien-miosien-motiliteitsessaiëring. n hierdie tesis streef ons na die modellering en verstaan van dié sisteem. Daar is egter ook wyer belangstelling in hierdie soort stelsels, aangesien die aktien-miosien-motiliteitsessaiëring ’n voorbeeld van ’n aktiewe stelsel is. Ons stel eers ons model wiskundig op, en begin dan deur die dinamika van ’n enkele aktienfilament in ’n motiliteitsessaiëring te ondersoek deur gebruik te maak van ’n Langevin- vergelyking. Ons volg daarop deur die effekte van ander filamente in te sluit. Dit word bereik deur middel van hidrodinamiese oorwegessaiëringings. Om aan te beweeg na ’n vollediger beeld van die dinamika van veelvuldige filamente in ’n digte sisteem, wend ons ons na die Martin-Siggia-Rose formalisme en ’n sistematiese benaderingskema bekend as die Lukrake-Fase Benadering (‘Random Phase Approximation’). Tydens ons verkenning van hierdie stelsel probeer ons immer voortdurend om eksperimenteel- meetbare korrelasiefunksies af te lei. Terselfdertyd identifiseer ons ook intrinsieke lengte- en tydskale.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentix, 74 pages : illustrations (some color)en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/126957
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshActin filamentsen_ZA
dc.subject.lcshActinen_ZA
dc.subject.lcshMicrofilament proteinsen_ZA
dc.subject.lcshLangevin equationsen_ZA
dc.subject.lcshMyosin -- Mechanism of actionen_ZA
dc.subject.nameUCTDen_ZA
dc.titleDynamics of actin filaments in an actin-myosin motility assayen_ZA
dc.typeThesisen_ZA
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