FIG.2.

Fluorescence emitted by B. anthracis Δ14185 and B. subtilis WB600 expressing different GFP reporter genes from various promoters. Strains expressing the three versions of the gfp gene in conjunction with the indicated promoter cassettes were cultured in FAG liquid media. GFP expression was monitored from a bacterial culture drawn at an A₅₅₀ of 5.0 by scanning the emission between 450 and 550 nm at excitations of 410 nm for wt GFP and GFPuv and 488 nm for EGFP. (A) Emission scans of B. subtilis and B. anthracis cultures expressing wt gfp, driven by the Pamy, Ptms, and P43 promoters. (B) Emission scans of cultures expressing the wt gfp, gfpuv, and egfp genes driven by the P43 promoter. Note the lack of EGFP fluorescence (driven by the P43 promoter) in B. anthracis as opposed to the high fluorescence level in B. subtilis. (C) Fluorescence-activated cell sorter-based detection of fluorescent B. anthracis vegetative cells expressing gfpuv from the P43 promoter (shaded curve) versus nonfluorescent cells (solid curve). FL1-Height, fluorescence intensity per cell; counts, normalized fractions of cells.