THE ROLE OF EXTRA-CELLULAR FIBERS IN CELL-CELL INTERACTIONS DURING EARLY BIOFILM FORMATION

Bacteria in nature often reside in differentiated communities termed biofilms, which are hence considered to be an active interphase between uni-cellular and multicellular life states for bacteria. Biofilm formation is highly regulated and involves complex processes, such as those exhibited in pathogenesis and infections, thus studying the factors that regulate the formation and disassembly of biofilms are of great interest. Biofilms assemble an extracellular matrix (ECM) that anchors the cells to each other, promoting complex development. Additionally, functional amyloid-like proteins self-assemble into fibers, and account for common extracellular components in bacterial biofilms. In the model bacterium, Bacillis subtilis, the amyloid-forming protein TasA was found to have a critical role in the initial biofilm assembly process by attaching to the cell wall and mediating cell-to-cell adhesion. Interestingly, we recently found that TasA can act to anchor matrix producers and motile cells to generate aggregates, and that these aggregates collectively migrate towards the water-air interphase. This early event was found to promote biofilm formation. Now we aim to study the role of TasA monomers and fibers in cell-cell interactions during development of early standing liquid cultures (pellicles). Specifically we investigate how TasA affects cell fate decision, cell-cell communication and the switching rate that initiate primordial aggregate development, leading eventually to a mature pellicle. We combine high-precision microscopy and genetic tools to capture real-time, in-vivo images of single cell dynamics throughout the critical initial time points.