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While significantly resistant to heat and radiation, endospores can be destroyed by burning or by autoclaving at a temperature exceeding the boiling point of water, 100 °C. Endospores are able to survive at 100 °C for hours, although the larger the number of hours the fewer that will survive.
Endospores can last for decades in multiple hard conditions, such as drying and freezing. This is because the DNA inside the endospore can survive over a long period. Most bacteria are unable to form endospores due to their high resistance, but some common species are the genera Bacillus ( over 100 species) and Clostridium (over 160 species). [2]
B. subtilis can divide symmetrically to make two daughter cells (binary fission), or asymmetrically, producing a single endospore that is resistant to environmental factors such as heat, desiccation, radiation and chemical insult which can persist in the environment for long periods of time. The endospore is formed at times of nutritional ...
The location of an endospore within a cell is species-specific and can be used to determine the identity of a bacterium. Dipicolinic acid is a chemical compound which composes 5% to 15% of the dry weight of bacterial spores and is implicated in being responsible for the heat resistance of endospores. Archaeologists have found viable endospores ...
Endospores show no detectable metabolism and can survive extreme physical and chemical stresses, such as high levels of UV light, gamma radiation, detergents, disinfectants, heat, freezing, pressure, and desiccation. [95] In this dormant state, these organisms may remain viable for millions of years.
Two genera of bacterial pathogens are known to produce endospores: the aerobic Bacillus and anaerobic Clostridium. [7] Dipicolinic acid forms a complex with calcium ions within the endospore core. This complex binds free water molecules, causing dehydration of the spore. As a result, the heat resistance of macromolecules within the core increases.
A stress response that can occur under conditions that are non-advantageous, but also non-lethal, is the creation of a biofilm. In this response, bacterial cells can secrete extracellular polymeric substances to form a film that can provide support to the bacterial colony, such as by improving their ability to adhere to a surface. [4]
These serine molecules eventually produce 2 molecules of 2-phosphoglycerate, with one molecule going towards biomass and the other being used to regenerate glycine. Notably, the regeneration of glycine requires a molecule of CO 2 {\displaystyle {\ce {CO2}}} as well, therefore the Serine pathway also differs from the other 3 pathways by its ...