FIG 1 .

The sopE gene induces iNOS expression and enhances the growth of S. Typhimurium in the intestine. Groups of streptomycin-pretreated mice were infected with the SL1344 wild type (CAL63, sopE⁺) or a sopE mutant (CAL88, sopE). Groups of mice were euthanized at the indicated time points. For all groups, n = 4 except for the day 2 sopE⁺ group (n = 3) (a) Analysis of bacterial numbers in the colon contents. Boxes in whisker plots represent the second and third quartiles, while lines indicate the first and fourth quartiles. (B) Nos2 mRNA levels in the mucosa were quantified by real-time PCR. Bars represent geometric mean Nos2 copy numbers per 100 copies of glyceraldehyde 3-phosphate dehydrogenase (Gapdh) mRNA ± the standard errors. (C) Levels of iNOS protein in the mucosa from mice infected with sopE⁺ (lanes 1 to 4) or sopE mutant (lanes 5 to 8) strains were determined by Western blotting (top panel). Detection of tubulin by Western blotting served as a loading control (bottom panel). Each lane represents protein extracts isolated from one animal. Molecular masses of standard proteins are indicated on the right. (D) Quantification of iNOS levels in Western blot assays by densitometry. Each square represents the intensity of the iNOS signal divided by the intensity of the tubulin signal from one animal. Significance is based on the two-tailed Student t test. *, P < 0.05.