Functional analysis of the CS-CbnK-CbnR three-component regulatory system in a homologous (A) and heterologous (B) host. C. maltaromaticum LV17C and L. lactis MG1363 transformants carried pLQPBM1 and either pBRKR (WT columns), pBRKA239 R (KA239 columns), or pBRKRN62 (RN62 columns). The transformants were treated with 20 μg/ml of CS (white columns) or 0.05% trifluoroacetic acid (black columns). GusA activity was determined as described in Methods. Means ± standard error of triplicate assays are shown.