FIG 6.

Overexpression of y3555 increases the growth fitness of Y. pestis strains. Shown are the growth kinetics of the Y. pestis KIM6⁺ parental strain, Δy3550 mutant, Δy3555 mutant, and Δy3550 Δy3555 mutant alone or overexpressing either y3555 (pCR4::3555) or y3550 (pCR4::3550) in LB medium. Data represent the mean values of the results from three independent experiments. The growth rate (μ) calculated from regression analysis is given next to each strain name. Data were analyzed using one-way ANOVA and a Tukey post hoc test. Asterisks mark significantly different growth rates of mutant strains versus that of the parental strain.