Skip to main content
. 2020 Feb 20;9:e50629. doi: 10.7554/eLife.50629

Figure 6. Differential MreB-curvature correlations in filamentous cells are due to cell poles and cell bending.

(A–B) Phase-contrast image (A) and fluorescence intensity (B) of a representative filamentous E. coli expressing MreB-msfGFP and SulA (NO53/pDB192). Contours (cyan) are obtained by computational cell segmentation. Positive contour curvature is found at cell poles, bulges, and outer parts of spontaneously bent regions, while negative curvature is found at indentations and inner parts of bent regions. Straight cell segments (yellow) are defined as regions where the curvature of the spatially averaged centerline (magenta) is smaller than 0.05 μm−1. (C–D) Normalized average MreB intensity as a function of local contour curvature. Comparison between correlations obtained from full contours (black) and side walls (green) (C) and from side walls (green) and straight cell segments (magenta) (D). (E–F) Distributions of contour-curvature values corresponding to correlation plots in (C–D). Shaded region: Standard deviation between three biological replicates.

Figure 6—source data 1. Table containing all data presented in Figure 6 and Figure 6—figure supplements 1–2.
The file Dataset-Fig6.xlsx contains: Figure 6C-D For filamentous NO53 cells, numerical values of correlations between contour curvature and normalized MreB-msfGFP intensities for the full contour, side walls or flat regions with number of cells considered. Figure 6E-F For filamentous NO53 cells, numerical values of the distribution of contour curvatures for the full contour, side walls or flat regions with number of cells considered. Figure 6—figure supplement 1 For NO53 cells, numerical values of the (i) correlations between contour curvature and normalized MreB-msfGFP intensities, and (ii) distribution of contour curvatures for the full contour and side walls. Figure 6—figure supplement 2 For filamentous NO53 cells, numerical values of (i) correlations between curvature and normalized MreB-msfGFP intensities, and (ii) curvature distributions after applying curvature or intensity correction methods.

Figure 6.

Figure 6—figure supplement 1. Correlations between MreB and contour curvature in WT cells.

Figure 6—figure supplement 1.

Left. Normalized average MreB intensity as a function of local contour curvature in strain NO53 (mreB <> mreB msfGFP). Comparison between correlations obtained from full contours (black) and side walls (green). Right. Distributions of contour-curvature values corresponding to correlation plots on the left. Shaded areas show standard deviation between three biological replicates.
Figure 6—figure supplement 2. Loss of correlations between MreB and contour curvature after renormalizing either curvature or intensity for cell bending in filamentous cells.

Figure 6—figure supplement 2.

(A–B) Curvature correction. (A) Average MreB intensity as a function of contour curvature (black) and bending-corrected contour curvature (orange) in NO53/pDB192 (Plac::sulA). (B) Distributions of contour curvature (black) and corrected contour curvature (orange). Curvature correction leads to a narrower distribution while ~ 80% of local curvature values keep their original sign of curvature. (C–E) Intensity correction. (C) Average MreB intensity as a function of bending-corrected MreB-intensity (orange). Intensity is corrected for observed correlations between MreB intensity and centerline curvature in (D) (Materials and methods). (D) Average MreB intensity as a function of smoothened centerline curvature (using a Gauss filter of σ = 80 nm). (E) Centerline-curvature distribution. Shaded areas show standard deviation between three biological replicates.