Morphogenesis and Properties of the Bacterial Spore

This chapter focuses on the spore nucleoid, concentrating on the small acid-soluble spore proteins (SASP), which saturate the spore chromosome and play an important role in protecting spore DNA from damage. It also discusses spore cortex and germ cell wall, which concentrates on the precise structure of the peptidoglycan (PG) in these two layers, as well as the synthesis and function of these two structures. The spore coat is also discussed in the chapter, which covers the properties and functions of indi­vidual coat proteins, as well as the function and assembly of the coat structure itself. The spore cortex surrounds the spore core, between the inner and outer forespore membranes, and is composed predominantly of PG, although there may also be some proteins present. While the identities of such cortical proteins have not been established, good candidates are enzymes involved in cortex lysis during spore germination. The outermost structure common to spores of all species is called the coat. This complex shell consists of a series of one or more morphologically distinct layers (depending on the species) that protect the spore from a variety of noxious molecules and from mechanical damage. The primary role of the coat is to protect the spore. It does this, at the very least, by acting as a sieve that excludes all but the smallest molecules from the spore interior and by providing mechanical strength.