Figure 3

Expression of P. aeruginosa fdx1. (A) For Northern blots, total RNA was hybridized to a [³²P]-dCTP-labelled fdx1-probe after electrophoretic separation and the autoradiogram shown is representative of several experiments. (B) The fdx1 transcript was detected by RT-PCR as a 136 bp amplicon and compared to the reference 350 bp-rRNA. The ratio fdx1/rRNA was arbitrarily set at 1 for cells at OD = 1, and compared with induced (i.e. calcium-depleted for T3SS induction) cells, and OD = 4.6 cells. Cumulative data from 3 experiments with standard error. (C) Time course evolution of the rRNA control (upper panel) and the fdx1 transcript (lower panel) after OD = 1-cells had infected J774 macrophages at multiplicity of infection of 10. The time of contact with macrophages is indicated in minutes and the size scale in bp is on the left of the panels.