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Endospores are resistant to most agents that would normally kill the vegetative cells they formed from. Unlike persister cells, endospores are the result of a morphological differentiation process triggered by nutrient limitation (starvation) in the environment; endosporulation is initiated by quorum sensing within the "starving" population.
Spores form a part of the life cycles of a diverse range of organisms such as many bacteria, plants, algae, fungi and some protozoa. In Saccharomyces cerevisiae (Kingdom Fungi), the set of early genes activating sporulation is induced by Ime1 (Inducer of Meiosis 1) and a regulator of middle genes is Ndt80p. [ 4 ]
There is debate as to whether endospory or heterospory evolved first. Some debate centers upon the requirement of endospory to develop before heterospory. [2] Endospory is assumed to follow heterospory but it has been suggested that without endospory, early plant species dependency on water fertilization and environmental impacts on gametophytic gene expression would have reduced the chances ...
The cyst walls of bacteria are formed by the thickening of the normal cell wall with added peptidoglycan layers. The walls of protozoan cysts are made of chitin , [ 11 ] a type of glycopolymer . The cyst wall of some ciliated protists is composed of four layers, ectocyst, mesocyst, endocyst, and the granular layer.
Sporogenesis is the production of spores in biology.The term is also used to refer to the process of reproduction via spores. Reproductive spores were found to be formed in eukaryotic organisms, such as plants, algae and fungi, during their normal reproductive life cycle.
Two gametes fuse to form a zygote, which develops into a new sporophyte. This cycle is known as alternation of generations . The spores of seed plants are produced internally, and the megaspores (formed within the ovules) and the microspores are involved in the formation of more complex structures that form the dispersal units, the seeds and ...
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]
They allow survival and are not a form of reproduction. [19] Under suitable conditions the spore germinates to produce a viable bacterium. Endospores are formed inside the mother cell, whereas exospores are formed at the end of the mother cell as a bud. [20]