Bacterial Endospre

Certain bacteria can form endospores in dry environments in a process called sporulation. They are called endospores because the spores form within the cell. Endospores offer great advantages to bacterial cells because they are extremely resistant to a number of harsh environments, including: heat, desiccation, radiation, chemicals, acids, and drying. The discovery of bacterial endospores was important to microbiology because it provided knowledge on proper methods for sterilization of culture media, foods, and other perishable items. Many organisms form spores, but the bacterial endospore is unique in its heat resistance capabilities. Endospores are bacterial structures (resting cells) formed by a few groups of bacteria as intracellular structures, but ultimately they are released as free endospores. Biologically, endospores are a fascinating type of cell. Endospores exhibit no signs of life, being described as cryptobiotic. They are highly resistant to environmental stresses such as high temperature (some endospores can be boiled for hours and retain their viability), irradiation, strong acids, disinfectants, etc. They are thought to be the most durable cell produced in nature. Although cryptobiotic, they retain viability indefinitely, such that under appropriate environmental conditions, they germinate back into vegetative cells. The primary function of most endospores is to ensure the survival of a bacterium through periods of environmental stress.

They are therefore resistant to ultraviolet and gamma radiation, desiccation, lysozyme, temperature, starvation, and chemical disinfectants.

Endospores are commonly found in soil and water, where they may survive for long period. An endospore is a dormant, tough, non-reproductive structure produced by a small number of bacteria from the Firmicute family. Endospores are formed mainly by two genera of Gram-positive bacteria: Bacillus,the aerobic sporeformers, and Clostridium, the anaerobic sporeformers. Both genera contain pathogens, and the endospores produced by these bacteria invariably play some role in the toxicity, transmission or survival of the pathogen.