Fig. 3.

Cryo-scanning electron micrographs of mature spore chains of the whi mutants expressing FtsZ. Column 1, S. coelicolor M145 (parental strain) and its whiA, whiB and whiG mutants harbouring control plasmid; column 2, same strains as shown in column 1 but now containing plasmid pSCF7, which expresses ftsZ from the constitutive ermE promoter; column 3, whiH, whiI, whiJ and ssgB mutants containing control plasmid; column 4, same strains as shown in column 3, but now containing plasmid pSCF7 (or pSCF7B for the ssgB mutant). Note that the constitutive expression of ftsZ restores sporulation to all whi mutants, while ssgB mutants produce spore-like bodies with highly variable sizes (see Fig. 5), most likely due to incorrect localization of FtsZ. For high-resolution TEM images of the spore chains see Fig. 5. All strains were grown for 5 days on SFM agar plates at 30°C. See Fig. S3 for lower magnification. All images presented at the same scale. Bar (top left), 1 μm