Figure 8. Increase of alkaline phosphatase activity in concentrated supernatants by ElpS overexpression.
(A) Alkaline phosphatase assays on concentrated supernatants. Specific alkaline phosphatase activity was measured by degradation of 5 mg/ml p-nitrophenyl phosphate (PNPP) in 100-fold concentrated supernatants from CB15N (WT), CB15N ΔelpS (ΔelpS), CB15N ΔelpS/pMR10 (ΔelpS/pMR10) and CB15N ΔelpS/pMR10-elpS (ΔelpS/pMR10-elpS) grown in poor medium. (B) Absence of detection of MreB in concentrated supernatants. Immunoblot with anti-MreB antibodies was done on cellular extracts and 100-fold concentrated supernatants from strains tested in (A) grown in poor medium. Proteins contained in samples tested in (A) were detected by electrophoresis and silver nitrate staining as a loading control for immunoblot.