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Small acid-soluble proteins (SASPs) are found in endospores. These proteins tightly bind and condense the DNA, and are in part responsible for resistance to UV light and DNA-damaging chemicals. [3] Visualising endospores under light microscopy can be difficult due to the impermeability of the endospore wall to dyes and stains. While the rest of ...
[1] [2] Once stained as part of a sample, these organisms can resist the acid and/or ethanol-based decolorization procedures common in many staining protocols, hence the name acid-fast. [ 2 ] The mechanisms of acid-fastness vary by species although the most well-known example is in the genus Mycobacterium , which includes the species ...
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.
Endospore stain on Bacillus subtilis.The spore is stained green and the vegetative cell is stained a pinkish red color. Endospore staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample. [1]
Another variation on this staining method is used in mycology to differentially stain acid-fast incrustations in the cuticular hyphae of certain species of fungi in the genus Russula. [16] [17] Some free endospores can be confused with small yeasts, so staining is used to identify the unknown fungi. [18]
B. anthracis endospores, in particular, are highly resilient, surviving extremes of temperature, low-nutrient environments, and harsh chemical treatment over decades or centuries. [ citation needed ] The endospore is a dehydrated cell with thick walls and additional layers that form inside the cell membrane.
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 taken from the intestines of Egyptian mummies as well as from lake sediments in Northern Sweden estimated to be many ...
Clostridium endospores have a distinct bowling pin or bottle shape, distinguishing them from other bacterial endospores, which are usually ovoid in shape. [ citation needed ] The Schaeffer–Fulton stain (0.5% malachite green in water) can be used to distinguish endospores of Bacillus and Clostridium from other microorganisms.