Euryarchaeota
Phylum of archaea From Wikipedia, the free encyclopedia
Phylum of archaea From Wikipedia, the free encyclopedia
Euryarchaeota (from Ancient Greek εὐρύς eurús, "broad, wide") is a kingdom of archaea.[3] Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines; halobacteria, which survive extreme concentrations of salt; and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C. They are separated from the other archaeans based mainly on rRNA sequences and their unique DNA polymerase.[4]
| Euryarchaeota | |
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| Halobacterium sp. strain NRC-1, each cell about 5 µm in length. | |
Scientific classification  | |
| Domain: | Archaea |
| Kingdom: | Euryarchaeota Woese, Kandler & Wheelis, 1990[1] |
| Phyla[2] | |
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| Synonyms | |
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The Euryarchaeota are diverse in appearance and metabolic properties. The phylum contains organisms of a variety of shapes, including both rods and cocci. Euryarchaeota may appear either gram-positive or gram-negative depending on whether pseudomurein is present in the cell wall.[5] Euryarchaeota also demonstrate diverse lifestyles, including methanogens, halophiles, sulfate-reducers, and extreme thermophiles in each.[5] Others live in the ocean, suspended with plankton and bacteria. Although these marine euryarchaeota are difficult to culture and study in a lab, genomic sequencing suggests that they are motile heterotrophs.[6]
Though it was previously thought that euryarchaeota only lived in extreme environments (in terms of temperature, salt content and/or pH), a paper by Korzhenkov et al published in January 2019 showed that euryarchaeota also live in moderate environments, such as low-temperature acidic environments. In some cases, euryarchaeota outnumbered the bacteria present.[7] Euryarchaeota have also been found in other moderate environments such as water springs, marshlands, soil and rhizospheres.[8] Some euryarchaeota are highly adaptable; an order called Halobacteriales are usually found in extremely salty and sulfur-rich environments but can also grow in salt concentrations as low as that of seawater 2.5%.[8] In rhizospheres, the presence of euryarchaeota seems to be dependent on that of mycorrhizal fungi; a higher fungal population was correlated with higher euryarchaeotal frequency and diversity, while absence of mycorrihizal fungi was correlated with absence of euryarchaeota.[8]
In 2022, the proposed kingdom Methanobacteriati was introduced to replace Euryarchaeota, which was claimed to be taxonomically invalid.[9]
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)[10] and National Center for Biotechnology Information (NCBI)[11]
| 16S rRNA based LTP_12_2021.[12][13][14] | |||||||||||||||||||||||||||||||||||||||
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Other phylogenetic analyzes have suggested that the archaea of the clade DPANN may also belong to Euryarchaeota and that they may even be a polyphyletic group occupying different phylogenetic positions within Euryarchaeota. It is also debated whether the phylum Altiarchaeota should be classified in DPANN or Euryarchaeota.[15] A cladogram summarizing this proposal is graphed below.[16][17] The groups marked in quotes are lineages assigned to DPANN, but phylogenetically separated from the rest.
| Dombrowski et al. 2019,[15] Jordan et al. 2017[16] and Cavalier-Smith 2020.[17] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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A third phylogeny, 53 marker proteins based GTDB 08-RS214.[18][19][20]
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Euryarchaeota s.s. |
