Fig. 4
Regulation of fciA and feoB expression. Overnight culture of S. maltophilia strains tested was inoculated into fresh LB without or with the additives as indicated at an initial OD450nm of 0.15. The fciA transcript (A) and feoB transcript (B) were quantified by qRT-PCR after a 5-h incubation. The concentrations of additives were 30 μg/ml for DIP, 1 mM for citrate, and 1 mM for ferric citrate. The relative transcript level was calculated using the transcript level of KJ cells grown in LB broth as 1. Black dots represent the results of three independent experiments. Bars represent the mean from three independent experiments. *, P < 0.01, significance calculated by Student’s t test