FIG 4 .

Effects of the rob deletion on biofilm elaboration and ica operon expression in FK300. (A) Biofilm elaboration in wild-type FK300 and its derivatives was assessed using the polystyrene microtiter plate assay described in Materials and Methods. The averages and standard errors from each sample are shown. sm, FK300 carrying a stop mutation at adenine nucleotide position 331 (A₃₃₁ to T₃₃₁); pC001, pKAT with rob (FK300); pC003, pKAT with rob (TF2758). (B) Quantitative measurements of icaR and icaADBC transcription by quantitative PCR. Total RNA preparation, cDNA synthesis, and then quantitative PCR were performed as described in Materials and Methods. Transcript levels in the rob deletion mutant compared to those in wild-type (WT) strain FK300 were assigned. The expression of the gyrB gene was used for sample normalization. Error bars indicate standard errors. (C) PIA/PNAG production was measured as described in the legend to Fig. 1.