Fig. 4.

The connector-mediated pathway of wild-type S. enterica demonstrates increased persistence of pbgP expression after activation in low Mg²⁺ and then repression in high Mg²⁺. (A) pbgP mRNA levels in wild-type S. enterica (14028s) and the engineered strain (EG17344) with direct pathway after bacteria were grown in inducing conditions (20 μM MgCl₂) for 2 h and then grown for the indicated times after the addition of 10 mM MgCl₂. The value at time 0 corresponds to the time the organisms were switched to repressing (i.e., 10 mM MgCl₂) conditions. (B) pbgP mRNA levels in wild-type (14028s) and pmrD-FLAG (EG13654) strains grown as described in A.