Fig. 3.

Decoupling the two fundamental modes of deformation. (A, Lower) At t = 0–16 min, an E. coli cell is growing in the presence of a constant flow for a period comparable to the cell division time. The deformation represents the sum of elastic and plastic modes (Movie S2). At t = 17 min, as the flow is abruptly turned off, the elastic mode vanishes and the cell partly recoils. The residual deformation reflects the cumulative effect of force transduction, which resulted in differential growth of the cell wall. At 17 min, in the absence of the flow, the cell straightens gradually as it grows. (A, Upper) The length of the cell increases exponentially despite the large deflections induced by the external mechanical forces—the mass-doubling time does not change appreciably during the experiment and is comparable to that of nonfilamentous cells. (B) Scatter plot of the experimental results for the tip position as time progresses through the snap-back experiment from A.