endoesporas

Endospores (also called endoesporas in some languages) are dormant, highly resistant structures formed by certain Gram-positive bacteria, notably Bacillus and Clostridium. Sporulation occurs when nutrients are scarce, and a mature endospore is released upon lysis of the mother cell. The spore’s core contains DNA and essential enzymes with very low water content, surrounded by the cortex (a thick peptidoglycan layer) and the protective spore coats; some species also have an outer exosporium. The core stores calcium and dipicolinic acid, along with small acid-soluble proteins that help stabilize DNA.

Endospores are remarkable for their resistance to heat, desiccation, radiation, and many chemical agents, enabling survival for long periods in soil and other environments. Germination is triggered by favorable conditions, leading to rehydration and return to a vegetative, metabolically active state.

Clinically and ecologically, endospores are significant. Some endospore-forming bacteria are pathogens (for example, Bacillus anthracis and Clostridium botulinum), while others play roles in nutrient cycles and food spoilage. Because of their durability, sterilization protocols—such as autoclaving—are designed to inactivate endospores to ensure safety.

Endospores also provide insights into bacterial differentiation and stress resistance. In biotechnology, certain spore-forming bacteria are used as model systems or for practical applications, including Bacillus subtilis in enzyme production and research contexts.