Condensed Matter Seminar: "Mechanical Cell Biology of Microbes"

Wed, 01/24/2018 - 16:00 - 17:00
Enrique Rojas (Stanford University)

Research in microbial physiology has traditionally focused on understanding biochemical pathways and, more recently, on elucidating the surprisingly complex structure of microbial cytoplasm.  On the other hand, the whether mechanical forces also play a role in controlling sub-cellular processes in microbes has been overlooked. I will highlight several novel paradigms by which microbes use mechanical (and electrical) factors as signals to control cell growth, division, and survival, and highlight how the remarkable mechanical properties of the cells are critical for these processes.  First, I will describe how, surprisingly, one of the cellular membranes (the "outer membrane") is a major load-bearing structure within Gram-negative bacteria, despite the fact that they also have a covalently cross-linked polymeric cell-wall.  Second, I will explain how the pathogenic bacterium Staphylococcus aureus harnesses internal hydrostatic pressure to drive sub-millisecond cell division in a process equivalent to mechanical fracture of the two daughter cells.  Finally, I will detail how Gram-positive bacteria use membrane tension and membrane depolarization as signals to ensure balanced synthesis of the plasma membrane and the cell wall.

David Rittenhouse Laboratory, A4