Figure 3

Growth ability of covS mutant S. pyogenes in THY broth. The CFU/ml after 23 h, THY broth culture of isogenic covS mutant strains (1529ΔcovS, SF370ΔcovS, and GT01ΔcovS), and parental isolates (1529, SF370, and GT01) are shown. At least three independent experiments were performed and they always yielded essentially the same results. The error bars indicate the standard errors of the means. (A) 5% CO2 was used as an experimental condition. The CFU/ml for overnight THY broth cultures of strains 1529ΔcovS and GT01ΔcovS were lower than those for their parental strains 1529 and GT01, respectively. The CFU/ml for overnight THY broth cultures of SF370ΔcovS were similar to that for the parental strain SF370. (B) Natural atmosphere (NA) was used as an experimental condition.