Many species of bacteria have developed abilities to swim, and in their natural environment, to live close to various interfaces. These properties are critical for their biological functions such as nutrient update, chemotaxis, adhesion, and biofilm formation. This project aims at understanding the interaction between swimming bacteria and surfaces. The common, noninfectious bacterium Caulobacter crescentus is used as a model system for the study of its swimming trajectory near a surface and its interaction with both solid surface and water/air interface. Commonly observed trajectories such as straight, circular, and locally curved ones will be recorded, along with the distance of the cell body from a surface. The experimental data will be analyzed by calculation of relevant physical interactions and computer simulations, which account for these physical interactions. The findings of the proposed study will shed light on the mechanisms of motility, chemotaxis, adhesion, and biofilm formation for a variety of microbes. The broader impact of the project includes a large educational component of classroom teaching and laboratory training, providing valuable exposure of graduate and undergraduate students to multidisciplinary research at the interface between physical and biological sciences. Outreach efforts involve partnership with local public schools through existing Brown University K-12 programs.
