FIG. 4.

Detection of β-galactosidase activity of the YaaH-LacZ fusion in sporulating cells. Strain ASK206 carrying yaaH′-lacZ was cultured in DS medium and sampled 4 h after the onset of sporulation. The cells in the same view were observed by three different methods as described in Materials and Methods. (A) Phase-contrast image. (B and C) Fluorescence images of cells stained with DAPI (B) and FDG (C). FS, forespore; MC, mother cell; Bar, 2 μm.