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. 2003 Oct;185(20):6185–6191. doi: 10.1128/JB.185.20.6185-6191.2003

FIG. 5.

FIG. 5.

Feedback derepression in a strain with increased rrn gene dose. By using β-galactosidase assays, promoter activities (from single-copy promoter-lacZ fusions) in strains carrying extra rRNA operons (plasmid pNO1301) (21) were compared to activities in strains containing a control plasmid (pNO1302) that does not make functional 16S or 23S rRNAs (21). Promoter activity is expressed relative to the average activity measured in strains containing the control plasmid. Growth and ATP and ppGpp extraction were performed as described in the legend for Fig. 3. Nucleotide concentrations are expressed relative to the concentration in the strain containing the control plasmid. Promoter activities in strains containing the control plasmid were as follows: rrnB P1, 137 MU; lacUV5, 1,789 MU; and rrnB P1(dis), 1,469 MU. The growth rate of the strain containing pNO1301 was 0.86 doublings/hour, and that of the strain containing pNO1302 was 1.11 doublings/hour.