PREPARATION AND CHARACTERIZATION OF INTACT AND FREE SPORES OF BACILLUS POPILLIAE DUTKY

Spores of Bacillus popilliae are enclosed within a large sporangium. In an effort to characterize the spores precisely, a method was developed to free them from their sporangia by sonic vibration. Separation of the free spores from sporangial debris was made by lysozyme treatment, centrifugation, and the Sacks and Alderton aqueous polymer two-phase system. The intact spores are fully refractile; they accept and retain malachite green applied by a modified Wirtz spore-staining technique. The free spores are elongated with rounded ends and measure 1.30–2.25 μ × 0.90–1.40 μ. Outgrowth of intact germinated spores is lowest when heat-activated at 80 °C and highest when heat-activated at 50 °C. Free spores are more heat sensitive than are intact spores, possibly because of damage by the sonic treatment. L-Alanine, adenosine, and glucose separately and in combination do not influence germination of either intact or free spores. Although potassium phosphate somewhat increased germination of intact spores, other salts were ineffective, but almost all salts increased germination of free spores.