Dependence of the heat resistance of bacterial endospores on their dipicolinic acid content.

Abstract

IT is generally accepted that mature spores from aerobic or anaerobic bacteria contain large quantities (5–15 per cent of the dry weight) of dipicolinic acid, whereas it is absent in the non-resistant vegetative cells1,2. Biosynthesis of dipicolinic acid is usually considered to be indicative of the formation of heat-resistant spores. In Clostridium roseum3 sporulation involves the development first of a refractile spore-like body, which is followed by the synthesis of dipicolinic acid, and later of a heat-resistant spore. In the aerobic bacteria, however, a close correlation between these three processes makes difficult the isolation of the first stage in sporulation.