FIG. 1.

6S RNA-deficient cells (ssrS1) are at a competitive disadvantage after 2 days of growth in stationary phase. (A) Equal numbers of 6S RNA null cells and wild-type cells were inoculated into LB medium and incubated at 37°C, and viable-cell counts were measured over time by plating. The data presented are averages for five duplicate cultures of KW370 (ssrS1 Nal^r) cocultured with ZK1143 (wild type, Str^r) and five duplicate cultures of KW371 (ssrS1 Str^r) and ZK1142 (wild type, Nal^r). Standard deviations were small enough not to be visible on the log scale. (B) 6S RNA-deficient cells and wild-type cells were inoculated into individual cultures (not in competition) and incubated at 37°C, and cell densities were measured over time by plating. The data shown are from a representative experiment containing two duplicates of each cell type: ZK1142, ZK1143, KW370, and KW371.