Conditions controlling commitment of differentiation in Bacillus megaterium

The developmental stage at which cells of Bacillus megaterium are committed to continue differentiation, i.e., sporulation, depends on both the previous growth medium and the new medium to which the cells are transferred for the commitment test. The latest "stage of no return," after which cells continue differentiation, no matter how rich in nutrients the medium, is reached as soon as the forespore is completely surrounded by a double membrane.