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Plenary Lecture 8: Microbial fortresses: the extracellular matrix and its impact on competition in bacterial biofilms

Presented by: 
C Nadell Princeton University
Thursday 30th October 2014 - 16:30 to 17:05
INI Seminar Room 1
Co-authors: Knut Drescher (Princeton University), Ned Wingreen (Princeton University), Bonnie Bassler (Princeton University)

Bacteria are now known to be highly interactive organisms that often live in groups, termed biofilms. Cells within a biofilm secrete a variety of extracellular compounds, many of which become part of a matrix that provides structural integrity and stress resistance to the bacterial group as a whole. The biofilm matrix is of central interest not only as a common feature of bacterial collective behaviour, but also as a target for the manipulation of microbial communities in contexts that are either helpful (e.g., probiotic applications and bioremediation) or harmful to humans (e.g., pathogenesis and industrial biofouling).

We aim to discover the forces governing biofilm composition with respect to secreted compounds, with an emphasis on the extracellular matrix. Using the model organism Vibrio cholerae, and with tools from molecular genetics and microfluidics, we demonstrate that matrix production confers a strong competitive advantage to matrix-secretors when co-inoculated with non-secretors. However, this advantage is accompanied by an ecological cost: impaired dispersal. We further show that biofilms can resist invasion by planktonic cells, and that different protein components of the matrix are responsible for invasion resistance in different regions of biofilms in accordance with their spatial localization. Our work has general implications for what evolutionary forces control bacterial group properties and highlights potential methods for the active manipulation of biofilms.
University of Cambridge Research Councils UK
    Clay Mathematics Institute The Leverhulme Trust London Mathematical Society Microsoft Research NM Rothschild and Sons