Colloquium

Dictyostelium Aggregation: A Meeting Point of Cell Biology and Nonequilibrium Physics

Herbert Levine
UC San Diego
Wednesday, April 6, 2005
Higgins 310, 4 pm

Dictyostelium  is a common soil amoeba often used as a model system to study many fundamental biological processes. Dictyostelium amoebae grow as independent cells, but aggregate to form multicellular organisms when challenged by adverse conditions such as starvation. This process involves up to 100,000 separate cells, which release a chemical signal (cAMP), which causes the cells to aggregate together via chemotaxis. Subsequently, cells differentiate and sort to form a 'mound' surrounded by an extracellular matrix. How do the cells know where to go? How is cell motion coordinated? How do cell-cell interactions stabilize the ‘mound’ structure? These are all questions that need to be answered using principles of non-equilibrium physics and basic cell biology. This seminar will focus on some of the basic physics concepts that are involved in these particular processes, most notably non-linear waves in excitable media and flocking patterns of self-propelled particles.