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Bacterial endospores are resistant to antibiotics, most disinfectants, and physical agents such as radiation, boiling, and drying. The impermeability of the spore coat is thought to be responsible for the endospore's resistance to chemicals. The heat resistance of endospores is due to a variety of factors:
Endospores were first studied in 1876 by scientists Cohn and Koch. [3] It was found that endospores could not be stained using simple stains such as methylene blue, safranin, and carbol fuchsin. These scientists, along with a few others, found out that spores were dormant and resistant to heat.
Endospores are stained red, while the counterstain methylene blue stains the vegetative bacteria blue. Endospores are surrounded by a highly resistant spore coat, which is highly resistant to excessive heat, freezing, desiccation, as well as chemical agents. More importantly, for identification, spores are resistant to commonly employed ...
Perhaps the best known bacterial adaptation to stress is the formation of endospores. Endospores are bacterial survival structures that are highly resistant to many different types of chemical and environmental stresses and therefore enable the survival of bacteria in environments that would be lethal for these cells in their normal vegetative ...
Bacterial endospores are most resistant to disinfectants, but some fungi, viruses and bacteria also possess some resistance. [10] Disinfectants are used to rapidly kill bacteria. They kill off the bacteria by causing the proteins to become damaged and the outer layers of the bacteria cell to rupture. The DNA material subsequently leaks out.
Endospores exhibit more extreme isolation from their environment in terms of cell wall thickness, impermeability to substrates, and presence of dipicolinic acid, a compound known to confer resistance to extreme heat. [7] Microbial cysts have been likened to modified vegetative cells with the addition of a specialized capsule. [7]
Some genera of Gram-positive bacteria, such as Bacillus, Clostridium, Sporohalobacter, Anaerobacter, and Heliobacterium, can form highly resistant, dormant structures called endospores. [93] Endospores develop within the cytoplasm of the cell; generally, a single endospore develops in each cell. [94]
Mycobacterium tuberculosis (stained red) in tissue (blue).. Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures.