Oxymonad

{{Short description|Group of flagellated protozoa}} {{Automatic taxobox | image = Monocermonoides melolanthae.jpg | image_upright = 0.4 | image_caption = ''Monocercomonoides melolanthae'' | taxon = Oxymonadida | authority = Grassé 1952 emend. Cavalier-Smith 2003 | subdivision_ranks = Families | subdivision = * Oxymonadidae * Polymastigidae * Pyrsonymphidae * Saccinobaculidae | synonyms = * Oxymonadales * Polymastigales Engler 1898 * Polymastigida Calkins 1902 * Polymastigina Blochmann 1895 * Polymastigoda Seligo 1886 * Pyrsonymphales * Pyrsonymphida Grassé 1952 }}

The '''oxymonads''' (or '''Oxymonadida''') are a group of flagellated protists found exclusively in the intestines of animals, mostly termites and other wood-eating insects. Along with the similar parabasalid flagellates, they harbor the symbiotic bacteria that are responsible for breaking down cellulose. There is no evidence for presence of mitochondria (not even anaerobic mitochondrion-like organelles like hydrogenosomes or mitosomes) in oxymonads<ref>{{Citation |last=Hampl |first=Vladimir |title=Preaxostyla |date=2016 |work=Handbook of the Protists |pages=1–36 |editor-last=Archibald |editor-first=John M. |url=https://link.springer.com/10.1007/978-3-319-32669-6_8-1 |access-date=2024-04-15 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-32669-6_8-1 |isbn=978-3-319-32669-6 |editor2-last=Simpson |editor2-first=Alastair G.B. |editor3-last=Slamovits |editor3-first=Claudio H. |editor4-last=Margulis |editor4-first=Lynn|url-access=subscription }}</ref> and three species have been shown to completely lack any molecular markers of mitochondria.<ref>{{Cite journal |last1=Novák |first1=Lukáš V. F. |last2=Treitli |first2=Sebastian C. |last3=Pyrih |first3=Jan |last4=Hałakuc |first4=Paweł |last5=Pipaliya |first5=Shweta V. |last6=Vacek |first6=Vojtěch |last7=Brzoň |first7=Ondřej |last8=Soukal |first8=Petr |last9=Eme |first9=Laura |last10=Dacks |first10=Joel B. |last11=Karnkowska |first11=Anna |last12=Eliáš |first12=Marek |last13=Hampl |first13=Vladimír |date=2023-12-07 |editor-last=Dutcher |editor-first=Susan K. |title=Genomics of Preaxostyla Flagellates Illuminates the Path Towards the Loss of Mitochondria |journal=PLOS Genetics |language=en |volume=19 |issue=12 |article-number=e1011050 |doi=10.1371/journal.pgen.1011050 |doi-access=free |issn=1553-7404 |pmc=10703272 |pmid=38060519}}</ref>

It includes e.g. ''Dinenympha'', ''Pyrsonympha'', ''Oxymonas'',<ref name="pmid12836875">{{cite journal |author=Moriya S |title=Molecular phylogeny of three oxymonad genera: Pyrsonympha, Dinenympha and Oxymonas |journal=J. Eukaryot. Microbiol. |volume=50 |issue=3 |pages=190–7 |year=2003 |pmid=12836875 |doi= 10.1111/j.1550-7408.2003.tb00115.x|name-list-style=vanc|author2=Dacks JB |author3=Takagi A |display-authors=3 |last4=Noda |first4=Satoko |last5=Ohkuma |first5=Moriya |last6=Doolittle |first6=W. Ford |last7=Kudo |first7=Toshiaki|s2cid=26831383 |doi-access=free }}</ref> ''Streblomastix'',<ref>{{Cite journal |last1=Treitli |first1=Sebastian C. |last2=Kolisko |first2=Martin |last3=Husník |first3=Filip |last4=Keeling |first4=Patrick J. |last5=Hampl |first5=Vladimír |date=2019-09-24 |title=Revealing the metabolic capacity of Streblomastix strix and its bacterial symbionts using single-cell metagenomics |journal=Proceedings of the National Academy of Sciences |language=en |volume=116 |issue=39 |pages=19675–19684 |doi=10.1073/pnas.1910793116 |doi-access=free |issn=0027-8424 |pmc=6765251 |pmid=31492817|bibcode=2019PNAS..11619675T }}</ref> ''Monocercomonoides'', and ''Blattamonas''.<ref>{{Cite journal |last1=Treitli |first1=Sebastian C. |last2=Kotyk |first2=Michael |last3=Yubuki |first3=Naoji |last4=Jirounková |first4=Eliška |last5=Vlasáková |first5=Jitka |last6=Smejkalová |first6=Pavla |last7=Šípek |first7=Petr |last8=Čepička |first8=Ivan |last9=Hampl |first9=Vladimír |date=November 2018 |title=Molecular and Morphological Diversity of the Oxymonad Genera Monocercomonoides and Blattamonas gen. nov. |url=https://linkinghub.elsevier.com/retrieve/pii/S1434461018300683 |journal=Protist |language=en |volume=169 |issue=5 |pages=744–783 |doi=10.1016/j.protis.2018.06.005|pmid=30138782 |url-access=subscription }}</ref>

==Characteristics== Most Oxymonads are around 50 μm in size and have a single nucleus, associated with four flagella. Their basal bodies give rise to several long sheets of microtubules, which form an organelle called an axostyle, but different in structure from the axostyles of parabasalids. The cell may use the axostyle to swim, as the sheets slide past one another and cause it to undulate. An associated fiber called the preaxostyle separates the flagella into two pairs. A few oxymonads have multiple nuclei, flagella, and axostyles.

[[File:2023 Oxymonad.svg|center|thumb|upright=2|{{center|Representation of an oxymonad}}{{ordered list|Flagella (two pairs)| Basal bodies| Nucleus| Motile axostyle| Endoplasmic reticulum, the transport network for molecules going to specific parts of the cell| Reduced Golgi apparatus; modifies proteins and sends them out of the cell| Pinocytic pore, for filter feeding| Endosome, sorts material| Membrane-bound granules}}]]

==Relationship to ''Trimastix'' and ''Paratrimastix''== The free-living flagellates ''Trimastix'' and ''Paratrimastix'' are closely related to the oxymonads.<ref name="pmid11371592">{{cite journal |author=Dacks JB |title=Oxymonads are closely related to the excavate taxon Trimastix |journal=Mol. Biol. Evol. |volume=18 |issue=6 |pages=1034–44 |date=June 2001 |pmid=11371592 |doi= 10.1093/oxfordjournals.molbev.a003875|name-list-style=vanc|author2=Silberman JD |author3=Simpson AG |display-authors=3 |last4=Moriya |first4=S |last5=Kudo |first5=T |last6=Ohkuma |first6=M |last7=Redfield |first7=RJ|doi-access=free }}</ref><ref>{{Cite journal |last1=Zhang |first1=Qianqian |last2=Táborský |first2=Petr |last3=Silberman |first3=Jeffrey D. |last4=Pánek |first4=Tomáš |last5=Čepička |first5=Ivan |last6=Simpson |first6=Alastair G.B. |date=September 2015 |title=Marine Isolates of Trimastix marina Form a Plesiomorphic Deep-branching Lineage within Preaxostyla, Separate from Other Known Trimastigids (Paratrimastix n. gen.) |url=https://linkinghub.elsevier.com/retrieve/pii/S1434461015000462 |journal=Protist |language=en |volume=166 |issue=4 |pages=468–491 |doi=10.1016/j.protis.2015.07.003|pmid=26312987 |url-access=subscription }}</ref> They lack aerobic mitochondria and have four flagella separated by a preaxostyle, but unlike the oxymonads have a feeding groove. This character places the Oxymonads, ''Trimastix'', and ''Paratrimastix'' among the Excavata, and in particular they may belong to the metamonads. Molecular phylogenetic studies indeed place Preaxostyla (oxymonads, ''Trimastix'', and ''Paratrimastix'') in Metamonada.<ref>{{Cite journal |last1=Zhang |first1=Qianqian |last2=Táborský |first2=Petr |last3=Silberman |first3=Jeffrey D. |last4=Pánek |first4=Tomáš |last5=Čepička |first5=Ivan |last6=Simpson |first6=Alastair G.B. |date=September 2015 |title=Marine Isolates of Trimastix marina Form a Plesiomorphic Deep-branching Lineage within Preaxostyla, Separate from Other Known Trimastigids (Paratrimastix n. gen.) |url=https://linkinghub.elsevier.com/retrieve/pii/S1434461015000462 |journal=Protist |language=en |volume=166 |issue=4 |pages=468–491 |doi=10.1016/j.protis.2015.07.003|pmid=26312987 |url-access=subscription }}</ref><ref>{{Cite journal |last1=Stairs |first1=Courtney W. |last2=Táborský |first2=Petr |last3=Salomaki |first3=Eric D. |last4=Kolisko |first4=Martin |last5=Pánek |first5=Tomáš |last6=Eme |first6=Laura |last7=Hradilová |first7=Miluše |last8=Vlček |first8=Čestmír |last9=Jerlström-Hultqvist |first9=Jon |last10=Roger |first10=Andrew J. |last11=Čepička |first11=Ivan |date=December 2021 |title=Anaeramoebae are a divergent lineage of eukaryotes that shed light on the transition from anaerobic mitochondria to hydrogenosomes |url=https://linkinghub.elsevier.com/retrieve/pii/S0960982221013646 |journal=Current Biology |language=en |volume=31 |issue=24 |pages=5605–5612.e5 |doi=10.1016/j.cub.2021.10.010|pmid=34710348 |bibcode=2021CBio...31E5605S }}</ref>

==Taxonomy== {{cladogram |title=Cladogram of Oxymonadida<ref>{{Cite journal |last1=Treitlia |first1=Sebastian C. |last2=Kotykb |first2=Michael |last3=Yubukia |first3=Naoji |last4=Jirounkováa |first4=Eliska |last5=Vlasáková |first5=Jitka |last6=Smejkalováa |first6=Pavla |last7=Sípek |first7=Petr |last8=Cepicka |first8=Ivan |last9=Hampl |first9=Vladimír |title=Molecular and Morphological Diversity of the Oxymonad Genera Monocercomonoides and Blattamonas gen. nov. |journal=Protist |volume=169 |issue=5 |year=2018 |pages=744–783 |doi=10.1016/j.protis.2018.06.005|pmid=30138782 }}</ref> |{{clade| style=font-size:90%;line-height:80% |1={{Clade |1=Polymastigidae |2={{Clade |1=Saccinobaculidae |2={{Clade |1=Oxymonadidae |2={{Clade |1=''Opisthomitus'' |2=Pyrsonymphidae }} }} }} }} }} }}

* Order '''Oxymonadida''' Grassé 1952 emend. Cavalier-Smith 2003<ref>{{cite journal | website=Collection of genus-group names in a systematic arrangement | title=Part 1- Virae, Prokarya, Protists, Fungi | url=http://mave.tweakdsl.nl/tn/genera1.html | display-authors=etal | access-date=30 June 2016 | archive-url=https://web.archive.org/web/20160814234049/http://mave.tweakdsl.nl/tn/genera1.html | archive-date=14 August 2016 }}</ref> ** Family Oxymonadidae Kirby 1928 [Oxymonadaceae; Oxymonadinae Cleveland 1934] *** Genus ?''Metasaccinobaculus'' Freitas 1945 *** Genus ''Barroella'' Zeliff 1944 [''Kirbyella'' Zeliff 1930 non Kirkaldy 1906 non Bolivar 1909] *** Genus ''Microrhopalodina'' Grassé & Foa 1911 [''Proboscidiella'' Kofoid & Swezy 1926] *** Genus ''Opisthomitus'' Grassé 1952 non Duboscq & Grassé 1934 *** Genus ''Oxymonas'' Janicki 1915 *** Genus ''Sauromonas'' Grassé & Hollande 1952 ** Family Polymastigidae Bütschli 1884 [Polymastiginae Kirby 1931; Polymastigaceae; Streblomastigaceae; Streblomastigidae Kofoid & Swezy 1919] *** Genus ?''Paranotila'' Cleveland 1966 *** Genus ?''Tubulimonoides'' Krishnamurthy & Sultana 1976 *** Genus ''Blattamonas'' Treitli et al. 2018 *** Genus ''Brachymonas'' (Grassé 1952) Treitli et al. 2018 non Hiraishi et al. 1995 *** Genus ''Monocercomonoides'' Travis 1932 *** Genus ''Polymastix'' Bütschli 1884 non Gruber 1884 *** Genus ''Streblomastix'' Kofoid & Swezy 1920 ** Family Pyrsonymphidae Grassé 1892 [Pyrsonymphaceae; Pyrsonymphinae Kirby 1937 nom. nud.; Dinenymphidae Grassé 1911; Dinenymphinae Cleveland et al. 1934; Dinenymphaceae] *** Genus ''Dinenympha'' Leidy 1877 [''Pyrsonympha'' (''Dinenympha'') (Leidy 1877) Koidzumi 1921] *** Genus ''Pyrsonympha'' Leidy 1877 [''Pyrsonema'' Kent 1881; ''Lophophora'' Comes 1910 non Coulter 1894 non Kraatz 1895 non Moeschler 1890] ** Family Saccinobaculidae Brugerolle & Lee 2002 ex Cavalier-Smith 2012 [Saccinobaculinae Cleveland et al. 1934] *** Genus ''Notila'' Cleveland 1950 *** Genus ''Saccinobaculus'' Cleveland-Hall & Sanders & Collier 1934

== References == {{Reflist}} {{Metamonada}} {{Taxonbar|from=Q618894}}

Category:Flagellates Category:Metamonads Category:Anaerobes