FIG 6.
Survival of mice challenged with the ΔrbsA isogenic mutant of Y. pestis CO92 in a pneumonic plague model, and ribose utilization. (A) For each of the strains tested, 10 adult Swiss-Webster mice were challenged by the i.n. route with 11 LD50 and then observed for mortality for 21 days. Survival data were analyzed for significance by Kaplan-Meier survival estimates with the Bonferroni post hoc test. The P values are for comparison of the results for each of the strains to the results for WT CO92. (B) Growth of mutants and WT CO92 in a modified M9 minimal medium with or without supplementation with 0.4% ribose. Samples were taken at the time points indicated and plated for CFU counts. (C) At 16 h postinoculation, culture titrations were determined for the WT CO92(pBR322), ΔrbsA(pBR322), and ΔrbsA(pBR322-rbsA) strains grown in a modified M9 minimal medium with or without supplementation with 0.4% glucose or 0.4% ribose. Statistical significance was analyzed by one-way ANOVA with the Tukey post hoc test. The comparisons between groups indicated by asterisks and brackets are significant at a P value of <0.001.