Myxosporea is a class of microscopic parasites, belonging to the Myxozoaclade within Cnidaria. They have a complex life cycle which comprises vegetative forms in two hosts, an aquatic invertebrate (generally an annelid but sometimes a bryozoan) and an ectothermicvertebrate, usually a fish. Each host releases a different type of spore. The two forms of spore are so different that until relatively recently they were treated as belonging to different classes within the Myxozoa.
The taxonomy of both actinosporeans and myxosporeans was originally based on spore morphology. In 1994 the phylum Myxozoa was redefined to solve the taxonomic and nomenclatural problems arising from the two-host life cycle of myxozoans.[1][2] The distinction between the two previously recognised classes Actinosporea and Myxosporea disappeared and the class Actinosporea was suppressed, becoming a synonym of the class Myxosporea (Bütschli, 1881). The generic names of actinosporeans were retained as collective "type" names, and it was proposed that they be used to characterise different morphological forms of actinosporeans. Those remaining actinosporeans whose myxosporean stage is unattested are being retained as species inquirenda until their specific identity is established.
It has been hypothesized that myxosporeans might have evolved from a transmissible tumor of Polypodium. This hypothesis is called the "SCANDAL hypothesis", an acronym for speciation by cancer development animals, referencing its radical nature.[3][4]
Transmissionedit
Until the 1980s, direct transmission of myxosporeans was presumed. In 1984, it was shown experimentally that spores of Myxobolus cerebralis failed to produce infections when fed to salmonids.[2] To reproduce successfully, this species requires a tubificid worm as an intermediate host, in which the spores develop into a "species" of the "genus" Triactinomyxon. These spores develop inside the oligochaete into forms which are infective to salmonids. Such a life cycle, with two different sexual stages, resulting in two kinds of resistant spores, is unique amongst the parasitic organisms. This mode of life cycle has been confirmed in several other Myxobolus species. This mode of infection has also been proved in other families. Ceratonova shasta, an economically important parasite of salmonids, has been shown to use a polychaete worm as an alternate host.[5]
Direct transmission between fish has also been demonstrated, so far in three species of Enteromyxum.
Wikimedia Commons has media related to Myxosporea.
^Kent ML, Margolis L, Corliss JO (1994). "The demise of a class of protists: Taxonomic and nomenclatural revisions proposed for the protist phylum Myxozoa Grasse, 1970". Canadian Journal of Zoology. 72 (5): 932–937. doi:10.1139/z94-126.
^ abWolf K, Markiw ME (September 1984). "Biology contravenes taxonomy in the myxozoa: new discoveries show alternation of invertebrate and vertebrate hosts". Science. 225 (4669): 1449–52. Bibcode:1984Sci...225.1449W. doi:10.1126/science.225.4669.1449. PMID 17770061.
^Bartholomew JL, Whipple MJ, Stevens DG, Fryer JL (October 1997). "The life cycle of Ceratomyxa shasta, a myxosporean parasite of salmonids, requires a freshwater polychaete as an alternate host". The Journal of Parasitology. 83 (5): 859–68. doi:10.2307/3284281. JSTOR 3284281. PMID 9379291.
^Bolin, Jessica A.; Cummins, Scott F.; Mitu, Shahida A.; Schoeman, David S.; Evans, Karen J.; Scales, Kylie L. (2021-06-11). "First report of Kudoa thunni and Kudoa musculoliquefaciens affecting the quality of commercially harvested yellowfin tuna and broadbill swordfish in Eastern Australia". Parasitology Research. 120 (7): 2493–2503. doi:10.1007/s00436-021-07206-8. ISSN 1432-1955.
^Matos, Edilson; Videira, Marcela; Velasco, Michele; Sanches, Osimar; Clemente, Sergio Carmona de São; Matos, Patricia (December 2014). "Infection of the heart of Pimelodus ornatus (Teleostei, Pimelodidae), by Myxobolus sp. (Myxozoa, Myxobolidae)". Revista Brasileira de Parasitologia Veterinária. 23 (4): 543–546. doi:10.1590/s1984-29612014083. ISSN 1984-2961.
February 18, 2024
myxosporea, class, microscopic, parasites, belonging, myxozoa, clade, within, cnidaria, they, have, complex, life, cycle, which, comprises, vegetative, forms, hosts, aquatic, invertebrate, generally, annelid, sometimes, bryozoan, ectothermic, vertebrate, usual. Myxosporea is a class of microscopic parasites belonging to the Myxozoa clade within Cnidaria They have a complex life cycle which comprises vegetative forms in two hosts an aquatic invertebrate generally an annelid but sometimes a bryozoan and an ectothermic vertebrate usually a fish Each host releases a different type of spore The two forms of spore are so different that until relatively recently they were treated as belonging to different classes within the Myxozoa MyxosporeaKudoa septempunctata sporesScientific classificationDomain EukaryotaKingdom AnimaliaPhylum CnidariaSubphylum MyxozoaClass MyxosporeaBuetchli 1881OrdersBivalvulida MultivalvulidaSynonymsActinomyxea ActinosporeaTaxonomic status editThe taxonomy of both actinosporeans and myxosporeans was originally based on spore morphology In 1994 the phylum Myxozoa was redefined to solve the taxonomic and nomenclatural problems arising from the two host life cycle of myxozoans 1 2 The distinction between the two previously recognised classes Actinosporea and Myxosporea disappeared and the class Actinosporea was suppressed becoming a synonym of the class Myxosporea Butschli 1881 The generic names of actinosporeans were retained as collective type names and it was proposed that they be used to characterise different morphological forms of actinosporeans Those remaining actinosporeans whose myxosporean stage is unattested are being retained as species inquirenda until their specific identity is established It has been hypothesized that myxosporeans might have evolved from a transmissible tumor of Polypodium This hypothesis is called the SCANDAL hypothesis an acronym for speciation by cancer development animals referencing its radical nature 3 4 Transmission editUntil the 1980s direct transmission of myxosporeans was presumed In 1984 it was shown experimentally that spores of Myxobolus cerebralis failed to produce infections when fed to salmonids 2 To reproduce successfully this species requires a tubificid worm as an intermediate host in which the spores develop into a species of the genus Triactinomyxon These spores develop inside the oligochaete into forms which are infective to salmonids Such a life cycle with two different sexual stages resulting in two kinds of resistant spores is unique amongst the parasitic organisms This mode of life cycle has been confirmed in several other Myxobolus species This mode of infection has also been proved in other families Ceratonova shasta an economically important parasite of salmonids has been shown to use a polychaete worm as an alternate host 5 Direct transmission between fish has also been demonstrated so far in three species of Enteromyxum Examples of Myxosporean genera are Kudoa which attacks fish muscle 6 and Myxobolus which attacks the hearts of freshwater fishes 7 References edit nbsp Wikimedia Commons has media related to Myxosporea Kent ML Margolis L Corliss JO 1994 The demise of a class of protists Taxonomic and nomenclatural revisions proposed for the protist phylum Myxozoa Grasse 1970 Canadian Journal of Zoology 72 5 932 937 doi 10 1139 z94 126 a b Wolf K Markiw ME September 1984 Biology contravenes taxonomy in the myxozoa new discoveries show alternation of invertebrate and vertebrate hosts Science 225 4669 1449 52 Bibcode 1984Sci 225 1449W doi 10 1126 science 225 4669 1449 PMID 17770061 Panchin AY Aleoshin VV Panchin YV January 2019 From tumors to species a SCANDAL hypothesis Biology Direct 14 1 3 doi 10 1186 s13062 019 0233 1 PMC 6343361 PMID 30674330 Wilcox Christie 19 August 2019 Can New Species Evolve From Cancers Maybe Here s How Quanta Magazine New York City Simons Foundation Retrieved 6 December 2019 Bartholomew JL Whipple MJ Stevens DG Fryer JL October 1997 The life cycle of Ceratomyxa shasta a myxosporean parasite of salmonids requires a freshwater polychaete as an alternate host The Journal of Parasitology 83 5 859 68 doi 10 2307 3284281 JSTOR 3284281 PMID 9379291 Bolin Jessica A Cummins Scott F Mitu Shahida A Schoeman David S Evans Karen J Scales Kylie L 2021 06 11 First report of Kudoa thunni and Kudoa musculoliquefaciens affecting the quality of commercially harvested yellowfin tuna and broadbill swordfish in Eastern Australia Parasitology Research 120 7 2493 2503 doi 10 1007 s00436 021 07206 8 ISSN 1432 1955 Matos Edilson Videira Marcela Velasco Michele Sanches Osimar Clemente Sergio Carmona de Sao Matos Patricia December 2014 Infection of the heart of Pimelodus ornatus Teleostei Pimelodidae by Myxobolus sp Myxozoa Myxobolidae Revista Brasileira de Parasitologia Veterinaria 23 4 543 546 doi 10 1590 s1984 29612014083 ISSN 1984 2961 Retrieved from https en wikipedia org w index php title Myxosporea amp oldid 1188149147, wikipedia, wiki, book, books, library,
