Extent of cross-linking of germ cell wall of a variant of Bacillus cereus

The extent of cross-linking of diaminopimelic acid in germ cell wall peptidoglycan of Bacillus cereus var. alesti spores [strain A(−)], was found to be 13.5 ± 2.1%. This contrasted with a value of 40.3 ± 2.25% for the extent of cross-linking of vegetative cell wall of this organism. These data indicate that germ cell wall may be considerably less rigid than vegetative cell wall. The extent of cross-linking of germ cell wall and vegetative cell wall of a cortexless mutant, A(−)1, derived from A(−), were found to be 33.3 ± 3.2% and 42.6 ± 2.0% respectively. Apparently the cortexless mutant is altered in germ cell wall structure as well as in the ability to produce a cortex. Attempts were made to determine whether the extent of cross-linking of germ cell wall remained low in whole spores of A(−) and increased on germination, but these were inconclusive mainly because of problems associated with removal of hydrophobic spore coat protein.