Functional verification of regulator-encoding plasmids. Each regulatory gene, cloned into the pWSK29 vector, was introduced into a strain containing a mutation of the corresponding regulator and a lacZY reporter to a gene known to be activated by the regulator (The hilC-encoding plasmid was introduced into the wild type strain and compared to the control vector). β-galactosidase assays were performed on log-phase cultures (using ONPG) and the results represent a mean of at least three independent assays. (A) An invF::Tn5-lacZY reporter was used to verify the plasmids encoding hilA, hilC, hilD and sirA. (B) A sopB-lacZY fusion was used for the plasmid encoding invF and sicA; and (C), a srfH::MudJ reporter for the plasmid encoding ssrB.