PolyP was first extracted with the Kulaev method from the WT (grey histograms) and the phoP mutant (white histograms) of S. lividans TK24 grown on a Pi replete (A, B, C) or Pi limited (D, E, F, G) solid R2YE medium, at different time points throughout growth. This extraction yielded three fractions: (A, D) hot perchlorate fraction polyP (HMW polyP); (B, E) alkali-soluble fraction polyP (MMW polyP); (C, F) acid-soluble fraction polyP (SMW polyP). PolyP was also extracted with the Kornberg method from the WT and phoP mutant, at different time points on Pi limited R2YE medium. PolyP was run on urea-polyacrylamide gel (G). Lanes 1, 2, 3, 4, 5 contain size standard polyP, approximate length 20, 40, 60, 90 and 230 residues. The other lanes contain polyP preparations of the WT and phoP mutant. Note that the HMW polyP is not able to enter the gel and is therefore not detected. Only MMW and SMW polyP are visible.