FIG. 8.

Altered HemA regulation in strains bearing the hemA[KK] allele. (A) Loss of HemA protein in stationary phase. Cultures were grown in LB medium to an OD₆₀₀ of 0.5 (lanes a and d), to 3 h beyond stationary phase (lanes b and e), or overnight (lanes c and f). The extract from an equal number of cells was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and probed with anti-HemA MAb H23. Lanes a to c, HemA[WT]; lanes d to f, HemA[KK]. (B) The blot from the experiment shown in panel A was reprobed with anti-RpoS MAb R12 (8). (C) LT-2 wild-type cells were grown in LB medium to an OD₆₀₀ of 0.5 (lane a) or overnight (lane b) and probed with anti-HemA MAb H23. This blot shows results similar to those in panel A but was developed with a longer exposure time to increase the sensitivity. (D) Cultures of TE7725 hemA[WT] hemE env (a) and TE7726 hemA[KK] hemE env (b) were grown in LB medium containing 20 μg of heme/ml for 36 h, and the red fluorescence seen in lane b was visualized by using a UV light source. The image was made with the EagleEye II system (Stratagene).