Minimal Requirements for Commitment to Sporulation in Bacillus megaterium

Abstract

Commitment to sporulation was examined by means of both endotrophic sporulation and rejuvenation experiments. In both cases, a point of commitment to the completion of sporulation occurred at stage II. With 2 × 10 8 cells/ml, the process by which commitment occurred required 0.5 m m Mg 2+ , 10.0 m m phosphate, and an energy source (minimum of 5.0 m m acetate). For completion of sporulation and formation of normal, heat-resistant refractile spores, 0.3 m m Ca 2+ was required. Except for this Ca 2+ requirement, the completion of sporulation after commitment was independent of the nature of the surrounding medium. Some aspects of the utilization of these required substances were examined.