In
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
, the Korarchaeota are a
phylum
In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature ...
of the
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaeba ...
. The name is derived from the Greek noun koros or kore, meaning ''young man'' or ''young woman,'' and the Greek adjective archaios which means ''ancient.'' They are also known as Xenarchaeota.
Taxonomy
Korarchaeota is regarded as a
phylum
In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature ...
, which itself is part of the archaeal TACK superphylum which encompasses Thaumarchaeota (now
Nitrososphaerota), "
Aigarchaeota
The "Aigarchaeota" are a proposed archaeal phylum of which the main representative is '' Caldiarchaeum subterraneum''.. It is not yet clear if this represents a new phylum or a and order of the Nitrososphaerota, since the genome of ''Caldiarchae ...
", Crenarchaeota (now
Thermoproteota
The Thermoproteota (also known as crenarchaea) are archaea that have been classified as a phylum of the Archaea domain. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteris ...
), and "Korarchaeota".
Species
* "''Candidatus''
Korarchaeum cryptofilum
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebac ...
"
Elkins et al. 2008
* "''Candidatus''
Methanodesulfokores washburnensis"
McKay et al. 2019
Phylogeny
Analysis of their 16S rRNA gene sequences suggests that they are a deeply branching lineage that does not belong to the main archaeal groups,
Thermoproteota
The Thermoproteota (also known as crenarchaea) are archaea that have been classified as a phylum of the Archaea domain. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteris ...
and
Euryarchaeota. Analysis of the genome of one korarchaeote that was enriched from a mixed culture revealed a number of both Crenarchaeota- and Euryarchaeota-like features and supports the hypothesis of a deep-branching ancestry.
Reference species
The strain ''Korarchaeum cryptofilum'' was cultivated in an enrichment culture from a hot spring in Yellowstone National Park in USA 2008.
The cells are long and needleshaped, which gave the species its name, alluding to its "cryptical filaments". This organism lacks the genes for
purine
Purine is a heterocyclic aromatic organic compound that consists of two rings ( pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines ...
nucleotide
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecu ...
biosynthesis and thus relies on environmental sources to meet its purine requirements.
Ecology
The Korarchaeota have only been found in hydrothermal environments. They appear to have diversified at different phylogenetic levels according to temperature, salinity (freshwater or seawater), and/or geography.
Korarchaeota have been found in nature in only low abundance.
See also
*
List of Archaea genera
This article lists the genera of the Archaea. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI).
Phylogeny
National Center for ...
References
Further reading
Scientific journals
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Scientific books
Scientific databases
External links
{{Taxonbar, from=Q504947
Archaea phyla