Tuesday, May 28, 2013

1305.5843 (Ariel Amir et al.)

Elastic and Plastic Deformations of Bacterial Cell Walls    [PDF]

Ariel Amir, Farinaz Babaeipour, David R. Nelson, Suckjoon Jun
Cell walls define a cell shape in bacteria. They are rigid enough to resist large internal pressures, but also surprisingly plastic to grow under a wide range of external forces and geometric constraints. Understanding the mechanics of bacterial cell walls and the interaction between their growth and mechanical cues is a long standing problem. Here, we show that bacterial cell wall growth is affected by mechanical stress, leading to remarkable materials properties unique to living cells. By applying a precisely controllable hydrodynamic force to growing rod-shaped Escherichia coli cells, we show that they can significantly deflect either elastically or plastically depending on the duration of the applied force. Our experimental results are in a good quantitative agreement with the predictions of dislocation-mediated cell-wall growth. These findings provide insight into how bacteria use the material properties of cell walls to robustly maintain their shape under varying physical environments.
View original: http://arxiv.org/abs/1305.5843

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