Корархеоты: древняя ветвь архей из гидротермальных источников.

Proposed phylum within the Archaea

The Korarchaeota is a proposed phylum within the Archaea. 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. The name is equivalent to Candidatus Korarchaeota, and they go by the name Xenarchaeota or Xenarchaea as well.

The Korarchaeota are a proposed phylum in the domain, Archaea. They are thought to have diverged relatively early in the genesis of Archaea and are among the deep branching lineages. The evolutionary link between Asgard archaea and Korarchaeota of TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, Korarchaeota) is yet unknown. Since then only a few Korarchaeal genomes have been described. To check for Korarchaeota, samples from a variety of hot springs in Iceland and Kamchatka were gathered. According to the samples and analysis, the Icelandic samples contained about 87 distinct 16S ribosomal nucleic acid sequences, whereas the Kamchatkan samples contained about 33. Based on protein sequences and phylogenetic analysis of conserved single genes, the Korarchaeote was identified as a “deep archaeal lineage” with a possible relationship to the Crenarchaeota. Furthermore, given the known genetic makeup of archaea, the Korarchaeota may have preserved a set of biological traits that correspond to the earliest known archaeal form. 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.

Korarchaeota are a proposed phylum within the domain, Archaea, and therefore exhibit characteristics such as having a cell wall without peptidoglycan, as well as lipid membranes that are ether linked. They have a surface layer of paracrystalline protein. This surface layer, known as the S layer, is densely packed and consists of 1 2 proteins form various lattice structures and are most likely what maintains the cells’ structural integrity. Korarchaeota cells have an ultrathin filamentous morphology that may vary in length.

Korarcheota have only been found in hydrothermal environments ranging from terrestrial, including hot springs to marine, including shallow hydrothermal vents and deep sea hydrothermal vents. Previous research has shown greater diversity of Korarchaea found in terrestrial hot springs compared to marine environments. Korarcheota likely originated in marine environments and then adapted to terrestrial ones. Geographically, Korarcheota have been found in a variety of locations around the world including Japan, Yellowstone National Park, the Gulf of California, Iceland and Russia.