Figure 3

IutA protein induction and qRT-PCR analysis of iutA expression. A. Heat-extracted proteins of E. coli O104:H4 strains C3493 (German isolate) and CCSS001 (iutA::cat) grown on MacConkey (MC) or LB agar in the absence (MC or LB) or presence (MC + DP or LB + BS) of 2,2’-dipyridil (DP) were separated in 12.5% SDS-PAGE gels and stained with Coomassie brilliant blue. Molecular mass markers are indicated on the left and the heat-extracted IutA protein is depicted by an arrow on the right. B. E. coli O104:H4 strain C3493 was grown on LB, MacConkey, LB/DP and MacConkey/DP for approximately 18 h at 37 °C, RNA was extracted and cDNA synthesized. The fold variation of gene expression was obtained by the comparative cycle threshold (∆∆CT) method. The iutA expression expressed as a value of 1 represented bacteria grown in LB, and variations in expression in other media conditions are related to this value. The expression of iutA resulted in 2.15- (*, P = 0.01), 4.9- (*, P = 0.001) and 12.13-folds (*, P = 0.01), increase in bacteria grown on MacConkey, LB/DIP and MacConkey/DIP respectively. Student’s T-test was used for the statistical analysis.