Commitment to sporulation in Bacillus megaterium and uptake of specific compounds

Commitment of Bacillus megaterium cells to continue the sporulation process was tested at different times during the developmental period with respect to either addition of different carbon sources (sugars or amino acids) or dilution into media containing these. Organisms grown in minimal medium containing sucrose as sole carbon source were committed earliest with respect to aspartic or glutamic acid as sole carbon source, later with respect to fructose, glucose, glycerol or sucrose, and latest with respect to nutrient medium supplemented with casein hydrolysate. Addition of both aspartate and a carbohydrate resulted in later commitment than addition of either compound alone. The initial uptake rates of aspartate, glutamate, glucose and sucrose increased toward the end of growth in complex medium (but not in minimal medium for glucose and sucrose) and then decreased during the developmental period.