Speaker
Prof.
David R. Nelson
(Harvard University and Niels Bohr Institute)
Description
Recent experiments have revealed a remarkable growth
mechanism for rod-shaped bacteria: specialized proteins
associated with cell wall elongation move at constant
velocity in clockwise and counterclockwise directions on
circles around the cell circumference. We argue that this
machinery attaches to dislocations in the ordered
peptidoglycan cell wall, and study theoretically the
dynamics of these interacting defects on the surface of a
cylinder. Unlike the dislocations typical in materials
science, the motion is predominantly climb (glycan strand
extension) instead of glide. The activated motion of these
dislocations and the resulting dynamics within a simple
kinetic model show surprising effects arising from the
cylindrical geometry, with important implications for
bacterial growth. Recent experiments revealing plastic
deformation of bacterial cell walls in a hydrodynamic flow
will be presented as well.
Primary author
Prof.
David R. Nelson
(Harvard University and Niels Bohr Institute)
