Breviatea

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Breviatea
Undescribed breviates 2025 Aguilera-Campos-et-al.jpg
Differential interference contrast micrographs of four strains of undescribed marine breviates. Scale bars: 5 µm
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Clade: Podiata
Clade: Amorphea
Clade: Obazoa
Class: Breviatea
Cavalier-Smith 2004 in Cavalier-Smith et al., 2004 [1]
Order: Breviatida
Cavalier-Smith, 2004 [1]
Genera
Diversity
4 species

Breviatea, commonly known as breviate amoebae, [2] are a group of free-living, amitochondriate protists with uncertain phylogenetic position. [3] They are biflagellate, and can live in anaerobic (oxygen-free) environments. [3] [2] [4] They are currently placed in the Obazoa clade. [5] They likely do not possess vinculin proteins. [5] Their metabolism relies on fermentative production of ATP as an adaptation to their low-oxygen environment. [3]

Contents

The lineage emerged roughly one billion years ago, at a time when the oxygen content of the Earth's oceans was low, and they thus developed anaerobic lifestyles. Together with apusomonads, they are the closest relatives of the opisthokonts, a group that includes animals and fungi. [2] [6]

Characteristics

Mitochondrion-related organelles (MROs) are organelles that evolved from a degradation of ancestral, fully functional mitochondria. Among Breviatea, MROs are present in Pygsuia , Breviata and Subulatomonas . In the cells of Pygsuia, for which the complete transcriptome is known, there is a single smooth MRO that lacks a mitochondrial genome and most components of the electron transport chain. Of the citric acid cycle enzymes, which are present in the mitochondria in other organisms, only two are present in Pygsuia: fumarase and succinate dehydrogenase. In contrast, Lenisia cells contain multiple MROs with cristae. [6]

Evolution

Breviatea is a clade of basal eukaryotes. They are closely related to the apusomonads and the Opisthokonta supergroup, and together they compose the larger clade Obazoa, which is the sister group to Amoebozoa. [2] Within Breviatea, the four known species are distributed into smaller clades of two species each: one uniting Breviata with Subulatomonas , and one uniting Lenisia with Pygsuia . [3]

Podiata

Taxonomy

History

The class Breviatea was created in 2004 by British protozoologist Thomas Cavalier-Smith to group a problematic taxon previously known as 'Mastigamoeba invertens'. This organism, initially classified in the Archamoebae within phylum Amoebozoa, appeared to strongly diverge in phylogenetic trees based on ribosomal RNA and had a structure very different from other archamoebae. Because of these results, 'M. invertens' was separated into the order Breviatida, contained in the monotypic class Breviatea. [1] The organism was eventually renamed Breviata anathema . [7] A second genus and species, Subulatomonas tetraspora , was described in 2011. [8] Cavalier-Smith established a family-level rank, Breviatidae, for both genera in 2013. [9] The same year, a third genus and species of breviates was described, Pygsuia biforma , [2] later classified by Cavalier-Smith in a separate family Pygsuidae. [10] In 2016, a fourth breviate Lenisia limosa was described without a family rank. [3] [11]

Classification

There are currently four accepted genera, each containing only one species.

References

  1. 1 2 3 Cavalier-Smith, Thomas; Chao, Ema E.-Y.; Oates, Brian (2004). "Molecular phylogeny of Amoebozoa and the evolutionary significance of the unikont Phalansterium". European Journal of Protistology. 40: 21–48. doi:10.1016/j.ejop.2003.10.001.
  2. 1 2 3 4 5 6 Brown, Matthew W.; Sharpe, Susan C.; Silberman, Jeffrey D.; Heiss, Aaron A.; Lang, B. Franz; Simpson, Alastair G. B.; Roger, Andrew J. (2013-10-22). "Phylogenomics demonstrates that breviate flagellates are related to opisthokonts and apusomonads". Proceedings of the Royal Society B: Biological Sciences. 280 (1769) 20131755. doi:10.1098/rspb.2013.1755. ISSN   0962-8452. PMC   3768317 . PMID   23986111.
  3. 1 2 3 4 5 6 Hamann, Emmo; Gruber-Vodicka, Harald; Kleiner, Manuel; et al. (2016-06-09). "Environmental Breviatea harbor mutualistic Arcobacter epibionts". Nature. 534 (7606): 254–258. Bibcode:2016Natur.534..254H. doi:10.1038/nature18297. ISSN   0028-0836. PMC   4900452 . PMID   27279223.
  4. ↑ Elsas, Jan Dirk van; Trevors, Jack T.; Rosado, Alexandre Soares; Nannipieri, Paolo (2019-04-05). Modern Soil Microbiology, Third Edition. CRC Press. ISBN   978-0-429-60240-5.
  5. 1 2 Kang, Seungho; Tice, Alexander K.; Stairs, Courtney W.; Jones, Robert E.; Lahr, Daniel J. G.; Brown, Matthew W. (2021-07-26). "The integrin-mediated adhesive complex in the ancestor of animals, fungi, and amoebae". Current Biology. 31 (14): 3073–3085.e3. doi: 10.1016/j.cub.2021.04.076 . ISSN   0960-9822. PMID   34077702. S2CID   235273235.
  6. 1 2 Leger, Michelle M.; Kolísko, Martin; Stairs, Courtney W.; Simpson, Alastair G. B. (2019). "Mitochondrion-Related Organelles in Free-Living Protists". In Tachezy, Jan (ed.). Hydrogenosomes and Mitosomes: Mitochondria of Anaerobic Eukaryotes. Microbiology Monographs. Vol. 9 (2nd ed.). Springer Cham. doi:10.1007/978-3-030-17941-0. ISBN   978-3-030-17941-0. S2CID   199511756.
  7. 1 2 Walker, Giselle; Dacks, Joel B.; Embley, T. Martin (2006). "Ultrastructural Description of Breviata anathema, N. Gen., N. Sp., the Organism Previously Studied as "Mastigamoeba invertens"". Journal of Eukaryotic Microbiology. 53 (2): 65–78. doi:10.1111/j.1550-7408.2005.00087.x. PMID   16579808. S2CID   31046569.
  8. 1 2 Katz, Laura A.; Grant, Jessica; Parfrey, Laura Wegener; Gant, Anastasia; O'Kelly, Charles J.; Anderson, O. Roger; Molestina, Robert E.; Nerad, Thomas (November 2011). "Subulatomonas tetraspora nov. gen. nov. sp. is a Member of a Previously Unrecognized Major Clade of Eukaryotes". Protist. 162 (5): 762–773. doi:10.1016/j.protis.2011.05.002. PMID   21723191.
  9. ↑ Cavalier-Smith, Thomas (May 2013). "Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa". European Journal of Protistology. 49 (2): 115–178 Document online. doi:10.1016/j.ejop.2012.06.001. ISSN   0932-4739. PMID   23085100.
  10. ↑ Cavalier-Smith, Thomas (2022-05-01). "Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi". Protoplasma. 259 (3): 487–593. doi: 10.1007/s00709-021-01665-7 . ISSN   1615-6102. PMC   9010356 . PMID   34940909.
  11. ↑ Lamża, Łukasz. "Deep-branching eukaryotes and early events in protist evolution". Biological Reviews. n/a (n/a). doi:10.1111/brv.70101. ISSN   1469-185X.
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