TEM images of R. eutropha H16 (a) and of R. eutropha HF39 (b) after 24 h of growth on NB medium (=zero control [t=0 min after transfer to fresh NB-gluconate medium]). Cells were harvested, fixed and prepared for TEM as described in method section. All thin sections were stained with uranyl-acetate and lead citrate. Arrowheads indicate condensed cytoplasm resulting in an electron-transparent fringe between cytoplasm membrane and cytoplasm. Short arrows indicate the border between cytoplasm and denatured nucleoid. The long arrow in the left cell of (a) points to a small globular structure most likely representing an electron-transparent (“white”) remaining, not completely mobilised PHB granule. Note, the PHB granule is in close contact to nucleoid region. Bar represents 0.2 μm.