How do bacteria respond to the mechanics of their environment? To answer this question, we use concepts and techniques from physics and engineering. We mechanically probe single bacteria, then observe and quantify their behavior.
Bacteria rapidly adapt to changes in their environment by leveraging sensing systems that probe their surroundings. One common assumption is that these are responsive to signals that are chemical in nature. Yet, bacteria frequently experience changes in mechanical forces, for example as they transition from swimming to surface-bound states. Do single bacteria actively sense and respond to mechanical forces? We address this question in by characterizing how the pathogen Pseudomonas aeruginosa responds to surface contact.
The surface of bacteria is decorated with filaments only a few nanometers thick. In collaboration with the Kukura lab, we have developed iSCAT, a microscopy technique that allows us to directly visualize pili and flagella in live cells, without the need for labels. With this, we can finally understand the dynamic regulation of these surface structures, and how they help cells mechanically interact with their environments.
Biofilms and flow
Flow is ubiquitous in the environments of microbes, be it in industrial piping systems, in the wild, or during infection. We know very little about how hydrodynamic forces modulate biofilm architecture and the behavior of single cells within the collective. Our lab uses a combination of engineering, material science and microscopy techniques to answer this question.