Oxymonad

Oxymonad
Oxymonads
Scientific classification
Domain: Eukaryota
(unranked): Excavata
Phylum: Metamonada
Order: Oxymonadida

The Oxymonads are a group of flagellated protozoa found exclusively in the intestines of termites and other wood-eating insects. Along with the similar parabasalid flagellates, they harbor the symbiotic bacteria that are responsible for breaking down cellulose. Both groups lack mitochondria, and oxymonads also lack dictyosomes.

It includes Dinenympha, Pyrsonympha, and Oxymonas.[1]

Characteristics

Most Oxymonads are around 50 μm in size and have a single nucleus, associated with four flagella. Their basal bodies give rise to a 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.

Relationship to Trimastix

The free-living flagellate Trimastix is closely related to the oxymonads.[2] It lacks mitochondria and has four flagella separated by a preaxostyle, but unlike the oxymonads has a feeding groove. This character places the Oxymonads and Trimastix among the excavates, and in particular they may belong to the metamonads.

References

  1. ^ Moriya S, Dacks JB, Takagi A et al. (2003). "Molecular phylogeny of three oxymonad genera: Pyrsonympha, Dinenympha and Oxymonas". J. Eukaryot. Microbiol. 50 (3): 190–7. doi:10.1111/j.1550-7408.2003.tb00115.x. PMID 12836875. 
  2. ^ Dacks JB, Silberman JD, Simpson AG et al. (June 2001). "Oxymonads are closely related to the excavate taxon Trimastix". Mol. Biol. Evol. 18 (6): 1034–44. PMID 11371592. http://mbe.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=11371592. 

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Look at other dictionaries:

  • Parabasalid — Taxobox color = khaki name = Parabasalids domain = Eukaryota unranked phylum = Excavata phylum = Metamonada classis = Parabasalia classis authority = Honigberg 1973 subdivision ranks = Orders subdivision = Trichomonadida Cristamonadida… …   Wikipedia

  • Axostyle — An axostyle is a sheet of microtubules found in certain protozoa. It arises from the bases of the flagella, sometimes projecting beyond the end of the cell, and is often flexible or contractile, and so may be involved in movement. Axostyles occur …   Wikipedia

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