Growth phenotypes, cell shape and nucleoid morphology observations of the par mutant strains. (A and B) The cultures of the mutants were grown in antibiotic-free complex medium (TB) (A) and minimal medium (SH) (B). For complementation experiments, the wild type and the ΔparAmN-1 strains carrying the plasmid pMK-parABm were grown in the presence of kanamycin (20 μg/ml). One representative of three independent experiments is shown. (C) Microscopic analysis of the cell shape, cell division and DNA morphology of the wild type and par mutants grown in complex medium (TB). Shown are representative phase-contrast (Phase) and fluorescence images (Membrane, DNA) and a merge between the membrane and DNA images (Overlay). The cells were stained with carboxyfluorescein (for membranes) and with DAPI (for DNA) before imaging. White arrows show aberrant nucleoids. Scale bars, 2 μm.