FIG. 2.

Oral inoculation of FvB mice with Salmonella serovar Typhimurium evaluated by Northern blot analysis. Mice were orally inoculated with either buffer alone (lanes 1 to 4) or Salmonella in buffer (lanes 5 to 8). The mice were sacrificed after 24 h. Total RNA was isolated from distal small intestine of the above mice, fractionated by formaldehyde-agarose gel electrophoresis, blotted onto a nylon filter, and hybridized sequentially to the indicated probes. Each lane represents one mouse. (A) 14028s mouse virulent strain; (B) TK93 SPI1 type III secretion mutant, isogenic to 14028s strain.