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An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. [1] [2] The name "endospore" is suggestive of a spore or seed-like form (endo means 'within'), but it is not a true spore (i.e., not an offspring). It is a stripped-down, dormant form to which the bacterium can reduce itself.
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 ]
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 ...
Generally, the basic morphologies are spheres (coccus) and round-ended cylinders or rod shaped (bacillus). But, there are also other morphologies such as helically twisted cylinders (example Spirochetes), cylinders curved in one plane (selenomonads) and unusual morphologies (the square, flat box-shaped cells of the Archaean genus Haloquadratum ...
Bacterial spores have proven to be difficult to stain as they are not permeable to aqueous dye reagents. 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 ...
A well accepted example of pleomorphism is Helicobacter pylori, which exists as both a helix-shaped form (classified as a curved rod) and a coccoid form. [7] Legionella pneumophila , the species of intracellular bacteria parasite responsible for Legionnaire's disease , has been seen to differentiate within a developmentally diverse network. [ 8 ]
While often associated with gastrointestinal illness, B. cereus is also associated with illnesses such as fulminant bacterial infection, central nervous system involvement, respiratory tract infection, and endophthalmitis. Endophthalmitis is the most common form of extra-gastrointestinal pathogenesis, which is an infection of the eye that may ...
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).