FIG. 1.

Expression of PrgI and PrgJ in Salmonella mutant strains. Cultures of wild-type, invA, prgJ, and invJ strains were grown in LB broth containing 0.3 M NaCl at 37°C to an OD₆₀₀ of 0.8. Aliquots of 1 ml were removed, and TCA was added to a final volume of 10%. Cultures were placed on ice for 30 min and then pelleted by spinning at 10,000 × g for 20 min. The pellets were washed with ice-cold acetone and dried under a vacuum. Pellets were resuspended in loading buffer and loaded onto sodium dodecyl sulfate-12% polyacrylamide gels. After electrophoresis, the gels were transferred to nitrocellulose. The blots were incubated with either anti-PrgI or anti-PrgJ rabbit serum followed by horseradish peroxidase-conjugated goat anti-mouse antiserum. The blots were developed, and bands were detected by chemiluminescence.