Initial characterization of a temperature-sensitive rod--mutant of Bacillus subtilis

The general biological properties of a temperature-sensitive morphological mutant of Bacillus subtilis (168ts-200B) are described. At the restrictive temperature (45 C), cells grow as spheres which divide irregularly to form grapelike clusters. At the permissive temperature (30 C), the mutant grows as typical B. subtilis rods in short chains. A log-phase culture of rods (30 C) may be converted to spheres by transfer to 45 C. Reversion of spheres to rods occurs when the alternate temperature shift is made. Growth curves, deoxyribonucleic acid replication kinetics, and the morphology of mutant 168ts-200B are described.