Fig. 1

Quantitation demonstrates consistency among contour measurements from different imaging modalities, despite small differences. a E. coli cells imaged using phase contrast (PC), interior fluorescence (IF) from cytoplasmic GFP, and peripheral fluorescence (PF) from the surface marker Alexa 594-Wheat Germ Agglutinin. Top: original images; middle: segmentation output from Morphometrics; bottom: extracted contours and meshlines. The pole from which all contours are measured is marked by orange and maroon dots for the beginning and end of the contours, respectively. Meshlines are colored cyan if the cell contour has positive (outward) curvature at both endpoints, maroon if the contour has negative curvature (inward) at both endpoints, and yellow if the contour has opposite signs of curvature (indicating a region where the cell body curves). Scale bar: 5 μm. b Overlay of the PC, IF, and PF cell outlines from (a). c Branching mesh (top) and centerline mesh (bottom) of the cells in (a), using the PF contours. These meshes are used to measure width profiles along the cell. d Comparison of the single-cell width profiles from pole to pole among all three imaging modalities for the cell on the left in (a). PC contours consistently estimate larger widths than PF or IF contours. e The PC, IF, and PF contours have similar curvature profiles, with slight differences consistent with width differences in (d). f Differences in cell-length measurements among imaging modalities are consistent across a wide range of cell lengths. In the legend, the first and second modality for each color correspond to the measurements along the y- and x-axes, respectively. Black line is y = x. g In cell area measurements, differences in length between imaging modalities shown in (f) are exacerbated due to width-dependent offsets in cell widths between imaging modalities, as shown in (d)