Cell cycle of Synechocystis. A) Growing cells stained with DAPI (DNA) and FM1-43 (membranes), overlay of membranes (red), thylakoids (green) and DNA (blue). B) Overlay of membrane (red) and DNA (green) of representative cells of the 5 classes defined in the text. Numbers indicate the percentage of cells present in a certain stage in an exponentially growing culture C) Fine structure of DNA (DAPI) structure in cells with a deep membrane (FM1-43) constriction and non-separated thylakoids (autofluorescence). Arrows point out non-separated nucleoids at the division plane. D) Exponentially growing cells stained with FM1-43 (membrane), DAPI (DNA), white triangles point out completely separated nucleoids having considerably different staining intensity, boxed triangles point out roughly equal nucleoids. E) Exponentially growing Bacillus subtilis cells, membrane and DNA stain analogous to panels A-D, white triangles indicate separated nucleoids in cells that do not yet have a visible division septum. Grey bars 2 μm.