Ultrastructural analysis of sporulation in a conditional serine protease mutant of Bacillus subtilis

The morphological characteristics of wild-type Bacillus subtilis and a temperature-sensitive serine protease derivative have been observed during vegetative and sporulation time periods. At 30 C wild-type and mutant cells grow and sporulate identically. At 47.5 C wild-type and mutant cells grow identically, but the mutant cells are blocked at stage 0 or I in the sporulation sequence. Wild-type cells sporulate normally at 47.5 C.