Figure 7. M. smegmatis Δcpa shows normal growth behavior under standard culture conditions but displays a slight growth defect during carbon starvation.

(A) Msm parent and knockout cells were cultured in Middlebrook 7H9 medium at 37°C and cell density was measured at 600 nm at the indicated time points. Both strains showed identical growth behavior indicating that Cpa is dispensable during standard cell culture conditions. (B) cpa-knockout cells show impaired growth in the same medium devoid of glycerol as a main carbon source. Both strains were cultured in a minimal medium in absence of glycerol at 37°C. Both growth curves are representative of three or more independent experiments with the mean values ± SD plotted.

Figure 7—figure supplement 1. Western blot analysis of the Msm ∆cpa strain.

An anti-^MsmCpa antibody (bottom) was used to show the presence (left lane, wild-type M. smegmatis) or the absence (Msm ∆cpa) of the Cpa protein in the two Msm strains used in this study. An antibody against the E. coli RNA polymerase subunit β was used as a loading control (top).