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".
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.
et al. 2013; Kim, et
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.
et al. 2011; Wensink,
et al. 2012; Dunkel, et al.