Masters Degrees (Physics)

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Browsing Masters Degrees (Physics) by Subject "Actin filaments"

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    Dynamics of actin filaments in an actin-myosin motility assay
    (Stellenbosch : Stellenbosch University, 2023-03) Saffer, Olivia; Muller-Nedebock, Kristian K. ; Kriel, J. N.; Stellenbosch University. Faculty of Science. Dept. of Physics.
    ENGLISH 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.