FIG. 6.

Ratio of expression of F. tularensis genes during MDM infection to that during in vitro culture. Real-time RT-PCR experiments for each RNA sample were done in triplicate from two RNA samples. RNA samples were collected from infection of human MDM monolayers after 4 (filled bars) and 10 (open bars) h of infection and from in vitro-cultured bacteria growing in mid-logarithmic phase. The ratio of transcripts results from the amount of mRNA from MDM infection, normalized to 16S rRNA concentration, divided by the amount of product from in vitro-cultured F. tularensis bacteria at each time point. The increase in transcript for both genes was significant (P < 0.005) compared to the level of 16S rRNA transcripts at 4 and 10 h of MDM infection.