The lab focuses on understanding collective bacterial behaviors, using biofilm formation as a model system. Bacterial biofilms are surface-associated bacterial communities that are held together by an extracellular matrix. Cells within these communities are highly resistant to antibiotics and display strong phenotypic heterogeneity. Using microscopy, molecular biology techniques, and mathematical modeling, we study how bacteria form these complex multicellular biofilm communities, and how these biofilms affect bacterial ecology.
Biofilms in Ecology and Evolution
Why do bacteria form biofilms? Bacteria that are bound in biofilms are highly resistant against antibiotics and other chemical insults of the environment, which is a clear evolutionary advantage of forming biofilms. However, we recently discovered another reason for why bacteria may want to form biofilms: physical aspects of the biofilm life style strongly favor the evolution of simple social behaviors, such as the production of shared resources or "public goods".
[ Drescher, et al. 2014; Nadell, et al. 2013].
How do biofilms grow in realistic physical and chemical environments? Biofilms are often thought to occur as surface-attached films. However, in environmental conditions that mimic their natural habitats, biofilms of P. aeruginosa and S. aureus are deformed into string-like structures. We discovered that these structures have a mesh-like architecture that captures other cells that are flowing past to grow explosively fast and cause rapid clogging of various industrial, environmental, and medical flow systems.
[ Drescher, et al. 2013; Kim, et al. 2014]
Biophysics of Collective Behaviors
What can we learn about collective bacterial behaviors from physics? Many aspects of bacterial interactions are inherently physical. Some examples: During biofilm growth, cells push and pull on each other, while being embedded in an elastic matrix. Understanding the molecular transport of nutrients and metabolites through the biofilm also relies on physics. Before bacteria form biofilms, their swimming motility creates fluid flows that lead to physical interactions with surfaces and other bacteria.
[ Drescher, et al. 2011; Wensink, et al. 2012; Dunkel, et al. 2014;]