Figure 1.

RydC regulates biofilm synthesis in E. coli and S. enterica. (A) Microtiter dish biofilm mass measured by crystal violet staining in E. coli, S. enterica (bongori) and S. sonnei after 48-h incubation. (left) The E. coli strains are wild-type MG1655Z1, its isogenic ΔRydC derivative (ΔrydC), strain containing a multicopy plasmid pUC18 and one containing pUC18 encoding RydC expressed from its endogenous promoter sequence (pUC18-rydC). (right) The same pUC18 constructs were added to Salmonella and Shigella. The data represent the means and standard deviations of at least 10 replicates. (B) RydC expression levels in the recombinant strains from the three bacteria monitored by northern blots on total RNAs directly extracted from the biofilms. The 5S rRNAs are internal loading controls.