Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis.
<p>Microorganisms have evolved in a low Reynolds number environment and have adapted their behaviour to its viscosity. Here, we consider some features of behaviour observed in microorganisms and use hydrodynamic models to show that these behaviours emerge from physical interactions, including...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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2015
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| _version_ | 1797088321744142336 |
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| author | Bennett, R Rachel Bennett |
| author2 | Golestanian, R |
| author_facet | Golestanian, R Bennett, R Rachel Bennett |
| author_sort | Bennett, R |
| collection | OXFORD |
| description | <p>Microorganisms have evolved in a low Reynolds number environment and have adapted their behaviour to its viscosity. Here, we consider some features of behaviour observed in microorganisms and use hydrodynamic models to show that these behaviours emerge from physical interactions, including hydrodynamic friction, hydrodynamic interactions and mechanical constraints.</p> <p>Swimming behaviour is affected by surfaces and observations of <em>Vibrio cholerae</em> show that it swims near a surface with two distinct motility modes. We develop a model which shows that friction between pili and the surface gives the two motility modes. The model is extended to study the behaviour of bacteria which are partially attached to a surface. Observations of <em>Shewanella</em> constrained by a surface show several different behaviours. The model shows that different degrees of surface constraint lead to different types of behaviour; the flexibility of the flagellar hook and the torque exerted by the flagellar motor also cause different behaviours. Near surface behaviour is important for understanding the initial stages of biofilm formation.</p> <p><em>Chlamydomonas</em> swims using synchronous beating of its two flagella. A simple model of <em>Chlamydomonas</em> is developed to study motility and synchronisation. This model shows that the stability of synchronisation is sensitive to the beat pattern. Run-and-tumble behaviour emerges when we include intrinsic noise, without the need for biochemical signalling. The model is also used to show how observed responses of the flagella to light stimuli produce phototaxis. Finally we study hydrodynamic synchronisation of many cilia and consider the stability of metachronal waves in arrays of hydrodynamically coupled cilia.</p> <p>This thesis shows that physical interactions are responsible for many behavioural features and that physical models provide a useful technique for exploring open questions in biology.</p> |
| first_indexed | 2024-03-07T02:48:21Z |
| format | Thesis |
| id | oxford-uuid:accc7f3c-b472-4bb9-b821-59725a54ccb7 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:48:21Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | oxford-uuid:accc7f3c-b472-4bb9-b821-59725a54ccb72022-03-27T03:31:26ZPhysics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis.Thesishttp://purl.org/coar/resource_type/c_db06uuid:accc7f3c-b472-4bb9-b821-59725a54ccb7BiophysicsTheoretical physicsCondensed matter theoryEnglishOxford University Research Archive - Valet2015Bennett, RRachel BennettGolestanian, R<p>Microorganisms have evolved in a low Reynolds number environment and have adapted their behaviour to its viscosity. Here, we consider some features of behaviour observed in microorganisms and use hydrodynamic models to show that these behaviours emerge from physical interactions, including hydrodynamic friction, hydrodynamic interactions and mechanical constraints.</p> <p>Swimming behaviour is affected by surfaces and observations of <em>Vibrio cholerae</em> show that it swims near a surface with two distinct motility modes. We develop a model which shows that friction between pili and the surface gives the two motility modes. The model is extended to study the behaviour of bacteria which are partially attached to a surface. Observations of <em>Shewanella</em> constrained by a surface show several different behaviours. The model shows that different degrees of surface constraint lead to different types of behaviour; the flexibility of the flagellar hook and the torque exerted by the flagellar motor also cause different behaviours. Near surface behaviour is important for understanding the initial stages of biofilm formation.</p> <p><em>Chlamydomonas</em> swims using synchronous beating of its two flagella. A simple model of <em>Chlamydomonas</em> is developed to study motility and synchronisation. This model shows that the stability of synchronisation is sensitive to the beat pattern. Run-and-tumble behaviour emerges when we include intrinsic noise, without the need for biochemical signalling. The model is also used to show how observed responses of the flagella to light stimuli produce phototaxis. Finally we study hydrodynamic synchronisation of many cilia and consider the stability of metachronal waves in arrays of hydrodynamically coupled cilia.</p> <p>This thesis shows that physical interactions are responsible for many behavioural features and that physical models provide a useful technique for exploring open questions in biology.</p> |
| spellingShingle | Biophysics Theoretical physics Condensed matter theory Bennett, R Rachel Bennett Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis. |
| title | Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis. |
| title_full | Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis. |
| title_fullStr | Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis. |
| title_full_unstemmed | Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis. |
| title_short | Physics of microorganism behaviour: motility, synchronisation, run-and-tumble, phototaxis. |
| title_sort | physics of microorganism behaviour motility synchronisation run and tumble phototaxis |
| topic | Biophysics Theoretical physics Condensed matter theory |
| work_keys_str_mv | AT bennettr physicsofmicroorganismbehaviourmotilitysynchronisationrunandtumblephototaxis AT rachelbennett physicsofmicroorganismbehaviourmotilitysynchronisationrunandtumblephototaxis |