Figure 7.

Time-lapse microscopy using voltage sensitive dye DiBAC₄(3). Selected images of a time-lapse microscopy experiment carried out with B. subtilis cells stained with DiBAC₄(3). Phase contrast images (left panel) and DiBAC₄(3) fluorescence images (right panels) are depicted. Due to the strong fluorescence intensity difference between polarized and depolarized cells, the images are shown with two different contrast settings. High fluorescence intensity of DiBAC₄(3) indicates low membrane potential. An individual cell that failed to enter logarithmic growth and subsequently undergoes membrane depolarization, is indicated with an arrow. See Supplementary Movie 1 for an example of a whole time-lapse series. Strain used: B. subtilis 168 (wild type).