FIG 3.

Growth in liquid medium and invasion efficiency of the S. Typhimurium deletion mutants. (A) Wild-type (WT) S. Typhimurium SL1344, ΔasmA, ΔcorA, ΔrecA, and ΔydgT bacteria were grown in rich medium, and CFU were enumerated by serial dilution and plating onto LB-Miller agar. Means ± SD of data from three independent experiments are shown. Asterisks indicate data significantly different from those for the wild type (P < 0.01). (B) HeLa epithelial cells were infected with wild-type S. Typhimurium SL1344, ΔasmA, ΔcorA, ΔrecA, and ΔydgT bacteria, and the number of intracellular bacteria at 1 h p.i. was quantified by a gentamicin protection assay. Invasion efficiency was calculated as the number of internalized bacteria/inoculum × 100%. Means ± SD from four independent experiments are shown. An asterisk indicates data significantly different from those for the wild type.