FIG. 2.

Quantitation of morphological classes in sporulating cells of strains PY79, IB498, IB506, and IB507. Cells were cultured in DSM broth at 37°C and harvested for examination by electron microscopy 4 or 7 h after cessation of logarithmic growth. Morphological classes were used as indicated at the right: 1, no septa; 2, thin septum at polar position; 3, thick septum at polar position; 4, thin septum at midcell position; 5, thick septum at midcell position; 6, cell with forespore at stage III or later.