Fig. 5.

Relative importance of elastic vs. plastic modes. The snap-back of the cell upon switching off the flow (Fig. 3), parameterized in terms of the slope of the tip position, as measured for 66 cells (33 E. coli and 33 B. subtilis) in differing growth conditions [see the key in the figure for growth media, temperature, and flow rate (1× being the maximal flow rate)]. For each snap-back, we quantified its magnitude by measuring the deflection angle ϕ of the tip before and after the snap-back. The snap-back angle is approximately proportional to the initial angle of deflection when the angles are small, confirming the prediction of the dislocation-mediated growth theory (Supporting Information). The ∼1/2 slope shows that the contributions by the two fundamental modes of deformation (elastic vs. plastic) are comparable with one another, regardless of the temperatures and growth conditions. Error bars are propagated from the uncertainty in calculating cell tip and channel end positions during image analysis.