When the spores of Bacillus megaterium QM B1551 (ATCC 12872) were incubated with 5mM CdCl₂ at 30C, they underwent the early germination events, such as loss of heat resistance and release of calcium dipicolinate, in the same way as when they were germinated by glucose+KNO₃. However, germination by CdCl₂ caused no increase in the reducing groups in the cortex and no excretion of glucosamine-containing materials due to the hydrolysis of the cortex peptidoglycan. Addition of CdCl₂ at any time during germination by glucose+KNO₃ inhibited the release of glucosamine-containing materials from the spores, whereas removal of cadmium from the CdCl₂-germinated spores by treatment with cysteine restored the hydrolysis of peptidoglycan.
These results suggested that CdCl₂ caused the early events of spore germination but prevented the spores from undergoing the events following germination by inhibiting the enzymatic lysis of the cortex peptidoglycan. The conclusion from the study is that cortex degradation is not always required for the initiation of germination.