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Calcium dipicolinate, abundant within the endospore, may stabilize and protect the endospore's DNA. Small acid-soluble proteins (SASPs) saturate the endospore's DNA and protect it from heat, drying, chemicals, and radiation. They also function as a carbon and energy source for the development of a vegetative bacterium during germination.
Endospore staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample. [1] Within bacteria, endospores are protective structures used to survive extreme conditions, including high temperatures making them highly resistant to chemicals. [ 2 ]
Importantly, encystment is a process observed to precede cell division, [8] while the formation of an endospore involves non-reproductive cellular division. The study of the encystment process was mostly confined to the 1970s and '80s, resulting in the lack of understanding of genetic mechanisms and additional defining characteristics, though ...
It has been proposed that endospore formation has allowed for the survival of some bacteria for hundreds of millions of years (e.g. in salt crystals) [14] [15] although these publications have been questioned. [16] [17] Endospore formation is limited to several genera of gram-positive bacteria such as Bacillus and Clostridium. It differs from ...
Fig1. The sporulation process of Bacillus subtilis. Bacillus subtilis is a rod-shaped, Gram-positive bacteria that is naturally found in soil and vegetation, and is known for its ability to form a small, tough, protective and metabolically dormant endospore.
Endospore staining is particularly useful for identifying endospore-forming bacterial pathogens such as Clostridioides difficile. Prior to the development of more efficient methods, this stain was performed using the Wirtz method with heat fixation and counterstain.
The endospore is formed at times of nutritional stress and through the use of hydrolysis, allowing the organism to persist in the environment until conditions become favourable. Prior to the process of sporulation the cells might become motile by producing flagella , take up DNA from the environment, or produce antibiotics .
An endosperm is formed after the two sperm nuclei inside a pollen grain reach the interior of a female gametophyte or megagametophyte, also called the embryonic sac.One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus).