Nanobdellota - WikiHQ

Nanobdellota (previously "Nanoarchaeota", Greek for "dwarf or tiny ancient one") is a phylum of Archaea. The first species discovered, Nanoarchaeum equitans, was from a submarine hydrothermal vent in Iceland and described in 2002. In 2002, Harald Huber and his colleagues at the University of Regensburg and Max Planck Institute for Medical Research discovered a new archaea from a submarine hot vent in Iceland. The species could not be fitted into any of the known groups so that they created a new phylum "Nanoarchaeota" for the new species they named Nanoarchaeum equitans.

In 2022, Japanese scientists led by Shingo Kato described a new species Nanobdella aerobiophila discovered from a terrestrial hot spring in Japan. For the classification, they created family Nanobdellaceae, order Nanobdellales and class Nanobdellia. In 2023, they introduced a new phylum Nanobdellota for the species. According to the revised International Code of Nomenclature of Prokaryotes (ICNP, Prokaryotic Code) of 2022, the name of a taxon cannot be created using the same spelling of the stem taxon, genus name, which is not validly published. Nanoarchaeota was not a validly published name while Nanobdella is a valid name and thus, Nanobdellota is accepted as the correct name of the phylum, and a new kingdom Nanobdellati was created in 2023.

Species and diversity

Members of the Nanobdellota are associated with different host organisms and environmental conditions. Despite small size, a reduced genome and limited respiration, they have unusual metabolic features. For example, N. equitans has a complex and highly developed intercellular communication system.

The phylogeny of the Nanobdellota is anchored by its only cultured representative, Nanoarchaeum equitans, which clusters in a separate evolutionary group than other archaea, which have recently been reclassified. Further analysis has shown that N. equitans diverged early on in the evolution of Archaea, as indicated by the 16S rRNA sequence. This suggests that they occupy a deeply branching position within this group.

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and the National Center for Biotechnology Information (NCBI).

Class Nanobdellia Kato et al. 2022 ["Nanoarchaea" Huber et al. 2011; "Nanoarchaeia" Vazquez-Campos et al. 2021
Family "Tiddalikarchaeaceae" Vazquez-Campos et al. 2021]
Genus "Candidatus Rehaiarchaeum" Rao et al. 2023
"Ca. R. fermentans" Rao et al. 2023
Genus "Candidatus Acidifodinimicrobium" Luo et al. 2020
"Ca. P. acidiphilum" Baker et al. 2010
"N. equitans" Huber et al. 2002
"Ca. N. minuta" St. John et al. 2019
"Ca. N. acidilobi" Wurch et al. 2016
Family "Haiyanarchaeaceae" Rao et al. 2023
Genus "Candidatus Haiyanarchaeum" Rao et al. 2023
"Ca. H. thermophilum" Rao et al. 2023

thumb|Nanoarchaeum equitans

Characteristics

Cells of N. equitans are spherical with a diameter of approximately 400 nm, Cells of N. equitans contain a normal S-layer with sixfold symmetry with a 15 nm lattice constant. The genomes of described nanoarchaeotes demonstrate different degrees of reduction, which is compatible with a host dependent lifestyle. Both terrestrial hot springs and underwater hydrothermal vents have yielded isolates in the genus Nanoarchaeum . However, there is evidence that nanoarcheotes reside in a variety of habitats outside of marine thermal vents.