The sigma-F dependent gene sspA affects septum positioning development of spore chains in the filamentous bacterium, Streptomyces coelicolor. Septation was visualised using cell wall staining with fluorescent wheat germ agglutinin (green). Each pre-spore compartment contains a single chromosome stained by propidium iodide (red). The main image and the insert were taken using laser-scanning confocal microscopy and super-resolution, three-dimensional structured illumination fluorescence microscopy, respectively. For further details readers are referred to the article by Tzanis et al. on pp. 363–380 of this issue.