Low- p H Activation of Bacillus cereus Spores

Abstract

Heat activation of bacterial spores at low p H was investigated in detail. Unlike activation of spores in distilled water at a neutral p H, activation at low p H involves two superimposed processes: enhanced activation and death. Low- p H-activated spores failed to germinate in d -alanine, in contrast to spores activated at neutral p H, owing to the abolition of alanine-racemase activity. Morphological and permeability changes such as release and partial disruption of spores were dipicolinic acid-observed during low- p H activation. The kinetics pattern of low- p H activation, as well as the change in properties of the spores thereafter, suggest that the mechanism of low- p H activation differs from that of other kinds of heat-activation.