Fig. 1.
MreB persistently moves perpendicularly to the cell’s long axis in a representative cell. (A–C) DIC (A) and smoothed fluorescence images of the initial (B) and final (C) time points of a 100-s-long time lapse of two adjacent E. coli cells expressing MreB–Rfpsw. The blue line indicates a rough cell outline and the scale bar is 1 μm. (Inset of C) Sketch of the position of the focal plane at approximately one-fourth of the cell diameter (the point spread function is indicated in blue). (D and E) Intermediate snapshots, taken every 12.5 s, of the rectangular part of the lower cell highlighted in B and C. The resulting spot trajectory is highlighted in blue in E. (F) Kymograph of the interpolated fluorescence intensity along the dashed line in the first panel of E. Images were taken every 2.5 s. The horizontal positions of the raw (blue) and smoothed (red) trajectories are displayed. (G) The raw (blue) and smoothed (red) trajectory in the xy plane. (H and I) MreB trajectory velocity v (H) and orientation relative to the long cell axis ϕ (I) as a function of time t.