Fig 2. Loss of BrtA in B. bronchiseptica negatively impacts biofilm formation in vitro.

(A) RT-PCR using B. bronchiseptica cDNA as template to amplify intergenic regions between the lapA and lapG genes. The recA amplicon was used as a positive control for the constitutively expressed recA gene. cDNA obtained from wild type B. bronchiseptica grown in different NA concentrations was employed in these assays. Note: the RT-PCR assays used are not quantitative, but are useful for detecting the presence/absence of a transcript. (B) Biofilm development by the BbWT and BbΔbrtA strains cultured in SS medium either alone or supplemented with NA at the indicated concentration. Biofilm formation was assessed by PVC microtiter plate assays as described in the Materials and Methods. *, indicates a significant difference between the wild type and mutant with same concentration of NA, p<0.01. After incubation in static conditions, the medium was removed, the bacteria were stained with CV, and the extent of biofilm formation quantified. (C) Biofilm formation by the BbWT and BbΔbrtA strains assessed in SS supplemented with NA 2.0 mM in glass tubes.