FIG. 6.
H-NS-dependent repression of clyASTy in the E. coli K-12 strains YMZ19 (clyA hns+) (shaded bars) and YMZ16 (clyA hns) (solid bars) carrying different constructs. The bacteria were grown on LB agar plates at 37°C for 16 to 17 h before being harvested. Shown is the relative cytolytic activity as determined by quantification of the release of hemoglobin from erythrocytes (see Materials and Methods). Approximately 4.0 × 107 bacterial cells were used for the samples applied in each well of the microtiter plate, giving a final density of 4 × 108 cells per ml. The activity of YMZ19/pJON97 was arbitrarily set to 1.0. The error bars indicate standard errors of the mean from two separate experiments.