Bacteria having a centrally placed endospore include "Bacillus cereus". Germination involves the dormant endospore starting metabolic activity and thus breaking hibernation. The endospore consists of the bacterium's DNA, ribosomes and large amounts of dipicolinic acid. The primary dye for endospore staining is malachite green. While the rest of a bacterial cell may stain, the endospore is left colourless. When the environment becomes more favorable, the endospore can reactivate itself to the vegetative state. This is the classic counterstain in both Gram stains and endospore staining. The position of the endospore differs among bacterial species and is useful in identification. The dipicolinic acid helps stabilize the proteins and DNA in the endospore. Dipicolinic acid forms a complex with calcium ions within the endospore core. Most types of bacteria cannot change to the endospore form. It is implicated as responsible for the heat resistance of the endospore. This may be triggered by heating the endospore. Only one endospore is formed per cell. Sometimes the endospore can be so large the cell can be distended around the endospore.