1. Dipicolinic acid (15% of dry weight of the spore complexed with Ca ions), located in the core: thought to be involved in heat resistance (however, heat resistant mutants has been isolated)
2. Calcium: help increase resistance to wet heat, dry heat, and oxidizing agents.
3. Calcium - dipicolinic acid complexes: might stabilize spores nucleic acid
4. Small acid-soluble, DNA-binding proteins (SASPs): saturate spore DNA and protect it from heat, radiation, desiccation, and chemicals
5. Dehydrated core: cortex can remove water from the core protect it from heat and radiation damage
6. Spore coat: thick, impermeable, protects against enzymes and chemicals
7. DNA repair enzymes: repairs DNA once spores germinate.