Seminar: Modeling Differences in Motility of Flagellated Bacteria Near Walls
Abstract: It is well known that bacteria can be found in almost any environment on Earth and are very diverse. In particular, there are many differences between species of flagellated bacteria in morphology and patterns of motility. For example, some have a single flagellum while others have more than 20, and their distribution over the cell body varies. To probe the physical implications of, and understand reasons for, these variations, we develop models for the mechanical problem of bacterial swimming. We focus on the hydrodynamics of swimming in Newtonian fluid with rigid flagella. Earlier studies showed that morphology was important in determining the behavior of bacteria near interfaces, such as the walls of a channel. We will describe the behavior expected for a "canonical" model bacterium with a single flagellum, which resembles typical experimental observations, and contrast this with models of bacteria with two flagella. The bacterium Magnetococcus marinus has an unusual morphology that necessitates a two-flagellum model whereas other bacteria with multiple flagella can be qualitatively described by a one-flagellum model.
Bio: Henry Shum is an Assistant Professor in the Department of Applied Mathematics at the University of Waterloo. He studied Mathematics and Physics as an undergraduate at the University of Warwick, completed his doctoral degree in Mathematical Sciences at the University of Oxford, and gained postdoctoral experience at the University of Oxford (Department of Physics) and the University of Pittsburgh (Department of Chemical & Petroleum Engineering). His research interests are in modelling motility of microorganisms with an emphasis on fluid mechanics and fluid-structure interactions. More generally, he is interested in modeling chemical and physical processes that govern biological functions and applying these principles in bio-inspired artificial systems.