Figure 3.

Tracking single PolC-PAmCherry molecules in living B. subtilis cells. (a) Representative raw-data images of a single PolC-PAmCherry molecule (arrow) in a B. subtilis cell are shown; the molecule is easily identifiable and can be tracked over time. (b) No PolC-PAmCherry molecules can be identified by eye in the raw-data images in high-background experimental conditions. (c) Accurate background subtraction with SMALL-LABS enables single molecules to be detected and localized from the high-background movie in (b), and trajectories are obtained (colored lines). (d) Comparison of the measured single-molecule intensities of the fluorescent protein PAmCherry in live-cell movies with low background (white) and with a high background (red) as in (a) and (b) are shown. Scale bars, 1 μm. To see this figure in color, go online.