FIG. 2.

Effect of complementation with foreign CorA proteins on invasion of Caco-2 epithelial cells. (A) The ability of E. coli corA (MM3218), M. jannaschii corA (MM3203), or B. subtilis MgtE (MM3217) to complement the invasion defect of a corA mutant strain was determined. S. enterica serovar Typhimurium strains were allowed to invade Caco-2 epithelial cells for 1 h, and intracellular bacteria were left to replicate for 6 h in the presence of gentamicin, except with the M. jannaschii corA mutant, where replication was for 4 h. P values indicate t tests comparing the wild type (MM2089) to the other strains. Data represent the average of three independent experiments (two experiments for the M. jannaschii corA mutant). (B) Transport via the B. subtilis MgtE transporter expressed in S. enterica serovar Typhimurium. ⁵⁷Co²⁺ uptake was measured in the wild type (MM2089), a corA mutant strain (MM2242), and a corA mutant strain with a plasmid carrying a functional B. subtilis mgtE gene (MM3217). The data were normalized to the amount of ⁵⁷Co²⁺ uptake in wild-type cells in the absence of additional CoCl₂. The data shown are from a single experiment representative of two independent experiments. WT, wild type.