Monday, November 9, 2015 - 16:00 to 17:00
Weniger 116
Event Speaker: 
Tristan Ursell, University of Oregon
Local Contact: 
Weihong Qiu(Weihong.Qiu@physics.oregonstate.edu)

In bacteria, the reproducible and robust construction of the cell wall is integral to mechanical integrity and viability under osmotic stress. Antibiotics that disrupt cell wall construction ultimately lead to discontinuous mechanical failure of the cell. Our work explores the biophysics of cell growth and death, as a guide to understanding mechanisms that disrupt mechanical properties of the cell. We use a combination of cell wall fluorescent labeling, high resolution time-lapse microscopy, and computational image processing to characterize where, and with what dynamics growth occurs and morphology is regulated. Analysis of cell-surface fluorescence indicates that the cytoskeleton is present at sites of active growth and that depolymerization of the cytoskeleton causes homogeneous, unstructured growth and eventual cell death by rupture. When combined with cell-shape analysis, our data strongly suggest that dynamic localization of the bacterial cytoskeleton is part of a curvature sensing and growth feedback mechanism that orchestrates heterogeneous growth to maintain cell shape and regulate mechanical stress. These techniques pave the way for studying the detailed dynamics of growth-associated proteins and their disturbance by antibiotics. We will also discuss recent results of transport phenomena in collectively motile bacterial groups.