endosporeja

Endosporeja, commonly referred to as endospore, is a dormant, highly resistant structure formed by certain Gram-positive bacteria in response to environmental stress, such as nutrient limitation. Genera that produce endospores include Bacillus and Clostridium. Endospores enable survival under extreme heat, desiccation, radiation, chemical disinfectants and starvation, allowing bacteria to endure until conditions improve. When conditions become favorable again, the endospore can germinate and give rise to a vegetative cell.

Structure and formation: Endospores are composed of a central core with DNA and essential enzymes, protected by a cortex of peptidoglycan and a multilayer coat. The core contains low water content and high concentrations of dipicolinic acid and small acid-soluble proteins that stabilize DNA. Sporulation is a complex developmental process triggered by nutrient limitation and regulated by specific sigma factors; it involves asymmetric cell division, engulfment of the forespore, and maturation inside the mother cell. Germination externally triggered by nutrients returns the spore to vegetative growth.

Ecology and health: Endospores play a key role in the persistence of their producers in soils, dust and hospital environments. Pathogenic spore-formers include Bacillus anthracis and several Clostridium species (e.g., C. botulinum, C. tetani, C. difficile). Because spores resist many disinfectants, controlling them requires rigorous sanitation, often including autoclaving or high-level chemical treatments. In microbiology, endospores are detected by spore staining (Schaeffer-Fulton) and other methods.

Applications and relevance: Some non-pathogenic spore-formers (e.g., Bacillus subtilis) are used in research and industry as model organisms and in probiotic formulations. The study of endospore formation informs ecology, evolution and strategies for pasteurization and sterilization.