FIG. 1.

Expression profile of a hilE-lacZY reporter throughout the growth curves of E. coli and S. enterica serovar Typhimurium. Strains were grown with shaking overnight in Lennox broth and then reinoculated into 20 ml of Lennox broth. Samples were taken every 40 min after the cultures began actively growing. Levels of β-galactosidase activity were determined for each sample taken. Plasmid pMAB56 is a single-copy mini-F plasmid that carries 1,000 bp of the putative hilE promoter fused upstream of a promoterless lacZY gene. Experiments were performed at least three times.