Differential Regulation of Escherichia coli fim Genes following Binding to Mannose Receptors

Figure 3

Determination of the fimS invertible element orientation in strain NU149 mixed with plain Sepharose beads or mannose-coated Sepharose beads in pH 5.5 or pH 7.0 media by PCR analysis. The PCR analysis was performed with chromosomal DNA isolated from the NU149 cells using the INV and FIMA primers to amplify Phase-ON-oriented DNA (450 bp product), FIME and INV primers to amplify Phase-OFF-oriented DNA (750 bp product), and EcFtsZ1 and EcFtsZ2 primers to amplify the ftsZ gene (302 bp product). The products were standardized against the ftsZ product using ImageQuant software and the corrected values for both orientations were standardized to the respective 0 h time point. The lanes were loaded as follows: MW = molecular weight standard; lane 1, NU149 at time 0 h; lane 2, NU149 time 24 h, mannose-coated at pH 7.0; lane 3, NU149 time 24 h, plain at 24 h; lane 4, NU149 time 24 h, mannose-coated at pH 5.5; lane 5, NU149 time 24 h, plain at pH 5.5. All PCR products were electrophoresed on 1.5% agarose gels.