FIG. 2.

(A)PhtrA-GFP upon overexpression of β-toxin and β-toxoid, shown by internal GFP fluorescence over time (T) of B. subtilis HT100A containing either β-toxin of β-toxoid on an inducible plasmid. After induction at T₀ of β-toxin/β-toxoid, the response of the htrA promoter was measured by quantifying the average GFP fluorescence per cell using a flow cytometer. (B) PykoJ-GFP upon overexpression of β-toxin and β-toxoid, shown by internal GFP fluorescence over time of the B. subtilis PykoJ-GFP strain in its chromosome and either β-toxin or β-toxoid on an inducible plasmid. After induction at T₀ of β-toxin/β-toxoid, the response of the ykoJ promoter was measured by quantifying the average GFP fluorescence per cell using a flow cytometer. Cultures not induced were also measured. +, induced; −, not induced.