Electron micrographs show polar localization of glycogen in csrA mutant cells.

Electron micrographs of wild type E. coli cells (A), csrA mutant cells (B) and csrA ΔglgA double mutant cells (C). Three representative pre-divisional cells per strain are depicted. The last image in each row is a magnified view of the first image in this row. Only the csrA mutant (B) displays granular structures indicative of glycogen, and these structures localize to the cell poles (in these experiments, it is not possible to determine which of the two cell poles is the old pole). Cells from the other two strains show no evidence of glycogen granules. Size bars are 1μm.