Accumulation of [14C]glucose (A), [14C]serine (B) and [14C]glycerol (C) by M. smegmatis SMR5/pMS2 (wt, black), ML16 with the empty vector pMS2 (ML16, green), ML16/pMN016 (ML16+mspA, blue), ML16/pML003 (ML16+ompATb, red) and ML16/pML1450 (ML16+ompATb operon, pink) was measured. All assays were performed at 37 °C at final glucose, serine or glycerol concentrations of 20 μM. Uptake experiments were performed in triplicate and are shown with standard deviations.