Unusual Membranous Structures in Cytochrome α-deficient Mutants of Bacillus subtilis

SUMMARY: In cytochrome α-deficient mutants of Bacillus subtilis, which grow to a reduced extinction of 600 nm and cannot sporulate, exceptionally large membranous structures (mesosomes) were observed with the electron microscope. They appeared not only at the sites of septation but also attached to unfinished, unseparated cross-walls of cell division and prespore septa. The parental strain grew and sporulated normally and did not show any unusual membranous structures.