PSU Mark
Eberly College of Science Mathematics Department

Meeting Details

For more information about this meeting, contact Andrew Belmonte, Tim Reluga, Stephanie Zerby, Chun Liu.

Title:Hydrodynamics and collective behavior of the tethered bacterium Thiovulum majus
Seminar:Mathematical Biology and Physiology Seminar
Speaker:Alexander Petroff, Center for Studies in Physics and Biology, Rockefeller University
The ecology and dynamics of many microbial systems are shaped by how bacteria respond to evolving nutrient gradients and microenvironments. Here we show how the response of the sulfur-oxidizing bacterium Thiovulum majus to changing oxygen gradients cause cells to organize into large-scale fronts. We show that these dynamics occur in two steps. First, chemotactic cells moving up the oxygen gradient form a front that propagates with constant velocity. We then show, through observation and mathematical analysis, that this front becomes unstable to changes in cell density. Random perturbations in cell density create oxygen gradients, which lead to the formation of millimeter-scale fluid flows. We argue that this flow results from a nonlinear instability excited by stochastic fluctuations in the density of cells. These results provide a mathematically tractable example of how collective phenomena in ecological systems can arise from the individual response of cells to a shared resource.

Room Reservation Information

Room Number:MB114
Date:04 / 25 / 2014
Time:12:00pm - 01:00pm