Organism that lives within the body or cells of another organism
A representation of the endosymbiotic theory
An endosymbiont or endobiont[1] is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects.[2][3]
Endosymbiosis played key roles in the development of eukaryotes and plants. Roughly 2.2 billion years ago an archaea absorbed a bacterium through phagocytosis that eventually became the mitochondria that provide energy to all living cells. Approximately 1 billion years ago, other cells absorbed cyanobacteria that eventually became chloroplasts, organelles that produce energy from sunlight.[4] Some 100 million years ago, UCYN-A, a nitrogen-fixing bacteria became an endosymbiont of marine algae Braarudosphaera bigelowii, eventually evolving into a nitroplast.[5] Similarly, Diatoms in the family Rhopalodiaceae have evolved a diazoplast, a nitrogen-fixing organelle.[6]
Symbionts are either obligate (require their host to survive) or facultative (can survive independently).[7] The most common examples of obligate endosymbiosis are mitochondria and chloroplasts, which reproduce via mitosis in tandem with their host cells. Some human parasites, e.g. Wuchereria bancrofti and Mansonella perstans, thrive in their intermediate insect hosts because of an obligate endosymbiosis with Wolbachia spp.[8] They can both be eliminated by treatments that target their bacterial host.[9]
^Margulis L, Chapman MJ (2009). Kingdoms & domains an illustrated guide to the phyla of life on Earth (4th ed.). Amsterdam: Academic Press/Elsevier. p. 493. ISBN 978-0-08-092014-6.
^Mergaert P (April 2018). "Role of antimicrobial peptides in controlling symbiotic bacterial populations". Natural Product Reports. 35 (4): 336–356. doi:10.1039/c7np00056a. PMID 29393944.
^Little AF, van Oppen MJ, Willis BL (June 2004). "Flexibility in algal endosymbioses shapes growth in reef corals". Science. 304 (5676): 1492–1494. Bibcode:2004Sci...304.1491L. doi:10.1126/science.1095733. PMID 15178799. S2CID 10050417.
^Baisas, Laura (18 April 2024). "For the first time in one billion years, two lifeforms truly merged into one organism". Popular Science. Retrieved 26 April 2024.
^Wong, Carissa (11 April 2024). "Scientists discover first algae that can fix nitrogen — thanks to a tiny cell structure". Nature.com. Archived from the original on 14 April 2024. Retrieved 16 April 2024.
^"Genomic divergence within non-photosynthetic cyanobacterial endosymbionts in rhopalodiacean diatoms". www.ncbi.nlm.nih.gov. PMC 5638926. PMID 29026213. Retrieved 25 April 2024.
^Slatko, Barton E.; Taylor, Mark J.; Foster, Jeremy M. (1 July 2010). "The Wolbachia endosymbiont as an anti-filarial nematode target". Symbiosis. 51 (1): 55–65. Bibcode:2010Symbi..51...55S. doi:10.1007/s13199-010-0067-1. ISSN 1878-7665. PMC 2918796. PMID 20730111.
^Warrell D, Cox TM, Firth J, Török E (11 October 2012). Oxford Textbook of Medicine: Infection. OUP Oxford. ISBN 978-0-19-965213-6.
An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualistic relationship...
distinguish organelles from endosymbionts – whole organisms living inside other organisms – by their reduced genome sizes. As an endosymbiont evolves into an organelle...
organelle, originated some 100 million years ago from a cyanobacterial endosymbiont called UCYN-A2, which allows B. bigelowii to fix nitrogen and convert...
insects, and is in turn a host to symbiotic bacteria. The bacterial endosymbiont Ca. "Kinetoplastibacterium crithidii" maintains a permanent mutualistic...
nodules; single-celled algae inside reef-building corals; and bacterial endosymbionts that provide essential nutrients to about 10%–15% of insects.[citation...
Trichonympha is referred to as an endosymbiont. However, Trichonympha is also a host to bacterial symbionts. Both as an endosymbiont and as a host, Trichonympha...
significantly clarified plastid genome evolution, the horizontal movement of endosymbiont genes to the "host" nuclear genome, and plastid spread throughout the...
genus Amphidinium, and other taxa, as yet unidentified, may have similar endosymbiont affinities. The true Zooxanthella K.brandt is a mutualist of the radiolarian...
come from primitive eukaryotes capturing oxygen-powered bacteria as endosymbionts and transforming them into organelles called mitochondria. The earliest...
McCutcheon JP (September 2014). "Sympatric speciation in a bacterial endosymbiont results in two genomes with the functionality of one". Cell. 158 (6):...
in this genus, and some related genera, possess an obligate bacterial endosymbiont called Blochmannia. This bacterium has a small genome, and retains genes...
Plastids, like mitochondria, have their own DNA and are developed from endosymbionts, in this case cyanobacteria. They usually take the form of chloroplasts...
autotrophic algae called cryptomonads (or cryptophytes), which contain endosymbiont red algae whose internal chloroplasts (evolved via endosymbiosis with...
is a species of bacteria which was originally identified as a benign endosymbiont in plants, but has since been associated with disease in humans and cattle...
they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification...
Keeling PJ (March–April 2007). "Mitochondrial genome of a tertiary endosymbiont retains genes for electron transport proteins". The Journal of Eukaryotic...
family Burkholderiaceae. "Candidatus Caballeronia schumannianae" is an endosymbiont. Vandamme P, Peeters C, De Smet B, Price EP, Sarovich DS, Henry DA, Hird...
revealed by examining the phylogeny of their bacterial endosymbionts, especially the obligate endosymbiont Buchnera. The results depend on the assumption that...
Some Francisella species are pathogenic bacteria but some others are endosymbionts of ticks. Ticks do not use any other food source than vertebrate blood...
Dyall SD, Brown MT, Johnson PJ (April 2004). "Ancient invasions: from endosymbionts to organelles". Science. 304 (5668): 253–257. Bibcode:2004Sci...304...
of the host and the endosymbionts show orderly and electron-dense cellular structures, no digestion in either host or endosymbionts appears to have occurred...
commonly referred to as the host while the internal cell is called the endosymbiont. Chloroplasts are believed to have arisen after mitochondria, since all...
and Francisella endosymbionts are closely related to pathogens, there is a substantial risk of misidentification between endosymbionts and pathogens, leading...
glossinidia is a species of gram-negative bacteria that is a bacterial endosymbiont of the tsetse fly. Because of this relationship, Wigglesworthia has lost...
family Rhopalodiaceae also possess a cyanobacterial endosymbiont called a spheroid body. This endosymbiont has lost its photosynthetic properties, but has...
species. Ten subspecies are recognised. The species carries Wolbachia endosymbionts, which is an alpha-proteobacterium that is known to modify the reproduction...
bacterial and fungal endosymbionts reside is mostly unknown. Bacteriocyte location varies depending on the insect and endosymbiont type. These cells often...
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