Panels A and C. To ensure that equivalent amounts of total protein from each sample were assayed, the same volume of lysate from each sample was electrophoresed through an SDS-polyacrylamide and stained with Coomassie Blue R250 dye. Panels B and D. Western blots showing the relative expression of GFP from the different promoter-gfp constructs. The expression of GFP was detected using a rabbit anti-GFP antibody. Two transformants carrying the following constructs, pBSV2G-flaBp2-gfp (lanes 1 and 2), pBSV2G-flaBp35-gfp (lanes 3 and 4) and pBSV2G-flaBp3-gfp (lanes 5 and 6), were tested (Panel B). Similarly, GFP expression was assayed from transformants carrying the following mutations within the flaB promoter: pBSV2G-flaBp2-gfp (lanes 1 and 2) and pBSV2G-flaBp2sm-gfp (lanes 3 and 4), and pBSV2G-flaBp2C→G-gfp (lanes 5 and 6). Lane C is a promoterless negative control (pBSV2G-gfp) (Panel D).