FIG. 3.

Fluorescence levels and OD₆₀₀ for S. oneidensis MR-1 (filled circles), S. oneidensis DKN308 constitutively expressing GFP (open circles), and S. oneidensis DKN310 expressing GFP(AAV) from a ribosomal promoter, representing growth activity (filled inverted triangles). OD₆₀₀ is indicated by dashed lines, and fluorescence is indicated by solid lines. As cells grow through the exponential phase, the fluorescence levels increase, but when the stationary phase is reached, the fluorescence levels from the constitutively expressed GFP remain high whereas the fluorescence from the growth-active version decreases rapidly. The error bars indicate standard deviations of triplicate cultures; in some cases the error is less than the size of the symbol.