Figure 4From: Characterization of a novel chaperone/usher fimbrial operon present on KpGI-5, a methionine tRNA gene-associated genomic island in Klebsiella pneumoniaeThe fim2 locus appears to contribute to biofilm formation when expressed in E. coli HB101. (A) Results for biofilm formation assay on polystyrene for KR2107 and its three fim and/or fim2 isogenic mutants as determined by crystal violet absorbance data. Equivalent results, suggestive of no strain-to-strain differences, were obtained for assays on polyvinyl chloride plates (data not shown). (B) Biofilm formation assay based on heterologous expression of fim2 in E. coli HB101/pFim2-Ptrc. HB101 and HB101 carrying an empty pJTOOL-7 served as controls. Biofilm formation was quantified using crystal violet staining and absorbance was measured at 595 nm. Non-normalized crystal violet absorbance data are shown. (C) Biofilm formation assay results shown in (B) were normalized to take account of pre-wash total cell numbers based on OD595 readings performed at 48 h, just prior to washing off non-surface adherent cells and crystal violet staining. Data shown in all cases represent means and standard deviations of three biological replicates, each assayed in eight wells (n = 24). An asterisk indicates a highly significant difference (P < 0.0001) from HB101 and HB101/pJTOOL-7.Back to article page