Growth phase dependent clyA transcription. Bacteria were grown in LB medium (A) at 37C and samples were assayed for luciferase activity as described in Materials and Methods. The strains tested were: the UPEC derivative COE2 (clyA::luxAB), the E. coli K-12 strain BSN26 (clyA::luxAB) and the UPEC strain 536 clyA
+ (JON53) which was serving as a luciferase negative control. The growth curves (upper panel) are presented from a representative experiment. The data curves for luciferase activity (lower panel) represent the average value of three independent experiments and vertical bars indicate the standard deviations. (B) Immunoblot detection of ClyA and CRP proteins. The immunoreactive bands corresponding to ClyA and CRP are indicated with arrows. Bacteria were grown in LB medium at 37C. Whole cell lysates were prepared from samples collected during different growth phases from the logarithmic phase of growth until the stationary phase. Lane 1: UPEC strain 536. Lanes 25: strain JON53, OD600=1.6 (lane2), OD600=1.74 (lane 3), OD600=2.24 (lane 4) and OD600=2.7 (lane 5). Lanes 69: COE2, OD600=1.5 (lane 6), OD600=1.8 (lane 7), OD600=2.04 (lane 8) and OD600=2.5 (lane 9).