Bacterial Endospores

Abstract Species of the genera Bacillus and Clostridium form dormant, resistant cells are known as endospores in response to stressful conditions. Endospores form inside of a mother cell, or sporangia, via a modified, asymmetrical cell division pathway followed by a variety of spore‐specific modifications to cell structure and content. Once the spore is formed, it is metabolically dormant and highly resistant to various insults such as heat, noxious chemicals, desiccation and UV irradiation. Several significant pathogens are spore formers, which makes disease prevention via food and environment sterilisation challenging. The resistance properties of spores are derived from chemical and physical alterations such as dehydration and mineralisation of the cytoplasm, protective alteration of DNA structure by specialised proteins and formation of impermeable proteinaceous spore coats. Dormancy is ended when the spore enters an environment where spore germination is favourable. Key Concepts Bacterial endospores can survive for decades and are highly resistant to numerous environmental insults. The resistance properties of bacterial endospores contribute to their roles in food spoilage and in human and animal pathogenesis. Bacterial endospores are cells with specialised modifications to their structure and contents. Bacterial endospores are produced via a simple developmental process involving cooperative and regulated gene expression of two cells. Heat resistance of bacterial endospores is determined by several factors, the most important being the relative dehydration of the spore core. Bacterial endospores possess a unique mode of resistance to UV irradiation involving specialised DNA‐binding proteins.