FIG. 6.

ompS1 chromosomal promoter activity at low (L) and high (H) osmolarities in S. enterica serovar Typhi strains, as assessed by primer extension. IMSS-1 is the wild-type strain, IMSS-41 is the isogenic ΔompR derivative, hns99 is the isogenic transposon mutant, and STY9941 (hns99 ΔompR) is the isogenic double mutant. The DNA ladder sequence for ompS1 is shown on the left. The bands corresponding to the transcriptional start sites of the OmpR-dependent P1 promoter, the P2 OmpR-repressed promoter, and the ompA gene are marked. The amounts of total RNA used were 50 μg for the ompS1 transcriptional start site and 1 μg for ompA.