FIG 5 .

putA and glnA, and ntrY and ntrX are synchronously upregulated prior to exponential growth, which is accelerated by proline and glutamine. RNA samples for quantitative RT-PCR were prepared at different time points p.i. from THP-1 cells infected with host cell-free E. chaffeensis for E. chaffeensis 16S rRNA normalized against human GAPDH mRNA (A) and for putA and glnA (B) or ntrY and ntrX (C) normalized against bacterial 16S rRNA. Values relative to the amount at 0 h p.i. are shown. Data indicate the means ± standard deviations from three independent experiments performed in triplicate.