Figure 3. CshA is required for biofilm formation and reduces hemolysis. (A) Biofilm formation was analyzed by the crystal violet (CV) assay in polystyrene tubes after growth for 6 h in TSB medium with equal amounts of inoculated cells. The amount of biofilm was measured after solubilization of the CV in ethanol and measuring the absorbance at 570 nm. The error bars (standard deviation) are from 3 independent experiments. The differences between S30 + pMKgfp vs cshA::Mu + pMKgfp and cshA::Mu pMKgfp vs cshA::Mu pMKcshA were significant (p = 0.001, p = 0.014, respectively). (B) S30 wild type strain and its cshA mutant derivative were spotted onto rabbit and horse blood agar plates. Shown is one representative result from 5 independent experiments. (C) Inactivation of agrA in the cshA mutant restores biofilm formation and reduces hemolysis.