FIGURE 2.

Luciferase activity in both liquid culture (open bars) and crude lysate (filled bars). The three samples correspond to cultures of E. coli expressing luciferase from pJHD500 in: 1) K-12 BW25113, 2) K-12 BW25113 ΔNfsA, and 3) K-12 BW25113 Δfre. In the first set of measurements in vivo, aliquots (0.5 ml) of cells were assayed in triplicate using a bench top luminometer by the aldehyde injection technique (33). Measurements of luciferase activity in crude cell lysates were obtained using the flavin injection technique (34). The normalized value for K-12 BW25113 Δfre in the in vivo assay is given in the figure.