Figure 4

Schematic representation of pmrH and pmrD loci and determination of K. pneumoniae P _pmrH :: lacZ and P _pmrD :: lacZ activity. (A) Diagrammatic representation of the pmrH and pmrD loci. The large arrows represent the open reading frames. The relative positions of the primer sets used in PCR-amplification of the DNA fragments encompassing the P _pmrH and P _pmrD regions are indicated, and the numbers denote the relative positions to the translational start site. The name and approximate size of the DNA probes used in electro-mobility shift assay (EMSA) are shown on the left. The dashed boxes indicate the predicted PhoP and PmrA binding sequences and the alignment result is shown below. The identical nucleotide sequences are underlined. HP, hypothetical protein. (B) The β-galactosidase activities of log-phased cultures of K. pneumoniae strains carrying placZ15-PpmrH grown in LB, LB containing 10 mM MgCl₂, LB containing 0.1 mM FeCl₃ or 0.1 mM FeCl₃ plusing 0.3 mM deferoxamine were determined and expressed as Miller units. (C) The β-galactosidase activities of log-phased cultures of K. pneumoniae strains carrying placZ15-PpmrD grown in LB, LB containing 10 mM MgCl₂ or LB containing 0.1 mM FeCl₃ were determined and expressed as Miller units. The data shown were the average ± standard deviations from triplicate samples. *, P < 0.01 compared to the same strain grown in LB medium. **, P < 0.01 compared to the parental strain grown in LB medium. #, P < 0.01 compared to the parental strain grown in LB medium supplemented with ferric ions.