Fig. 2.

Glycerol can be used to induce spore formation by both phase variants. Both the yellow and the tan variants show the formation of phase-bright, coccoid-shaped cells (arrows) and vegetative, rod-shaped cells (arrowheads) after glycerol induction (panels 1 and 4). These phase-bright spores survive gentle sonication (setting 1.5, three pulses of 10 s each), whereas vegetative cells do not (panels 2 and 5). SEM analysis (magnification, ×14,000) shows coccoid cells of both glycerol-induced phase variants (panels 3 and 6). Bars, 1 μm.