Ignicoccus | |
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Ignicoccus hospitalis (with two smaller, symbiotic Nanoarchaeum equitans ) | |
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Genus: | Ignicoccus Huber, Burggraf, Mayer, Wyschkony, Rachel & Stetter 2000 |
Type species | |
Ignicoccus islandicus Huber & Stetter 2000 | |
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Ignicoccus is a genus of hyperthermophillic Archaea living in marine hydrothermal vents. They were discovered in samples taken at the Kolbeinsey Ridge north of Iceland, as well as at the East Pacific Rise (at 9 degrees N, 104 degrees W) in 2000. [1]
According to the comparisons of 16S rRNA genes, Ignicoccus represents a new, deeply branching lineage within the family of the Desulfurococcaceae. [2] Three species are known: I. islandicus, [1] I. pacificus [1] and I. hospitalis strain KIN4I. [3]
The archaea of the genus Ignicoccus have tiny coccoid cells with a diameter of about 2 μm, that exhibit a smooth surface, an outer membrane and no S-layer. [4]
They have a previously unknown cell envelope structure—a cytoplasmic membrane, a periplasmic space (with a variable width of 20 to 400 nm, containing membrane-bound vesicles), and an outer membrane (approximately 10 nm wide, resembling the outer membrane of gram-negative bacteria). The latter contains numerous tightly, irregularly packed single particles (about 8 nm in diameter) and pores with a diameter of 24 nm, surrounded by tiny particles, arranged in a ring (with a diameter of 130 nm) and clusters of up to eight particles 12 nm in diameter each. [4]
The two layers of membrane previously reported are actually a type of endomembrane system consisting of cytoplasmic protrusions. In I. hospitalis, these structures harbor the endosymbiotic archaeon Nanoarchaeum equitans . [3]
Ignicocci live in a temperature range of 70–98 °C (optimum around 90 °C). They gain energy by reduction of elemental sulfur to hydrogen sulfide using molecular hydrogen as the electron donor. [2] A unique symbiosis with (or parasitism by) Nanoarchaeum equitans has also been reported. [2]
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [5] and National Center for Biotechnology Information (NCBI) [6]
16S rRNA based LTP_06_2022 [7] [8] [9] | 53 marker proteins based GTDB 09-RS220 [10] [11] [12] | ||||||||||||||||||||||||||||||
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Nanoarchaeum equitans is a species of marine archaea that was discovered in 2002 in a hydrothermal vent off the coast of Iceland on the Kolbeinsey Ridge by Karl Stetter. It has been proposed as the first species in a new phylum, and is the only species within the genus Nanoarchaeum. Strains of this microbe were also found on the Sub-polar Mid Oceanic Ridge, and in the Obsidian Pool in Yellowstone National Park. Since it grows in temperatures approaching boiling, at about 80 °C (176 °F), it is considered to be a thermophile. It grows best in environments with a pH of 6, and a salinity concentration of 2%. Nanoarchaeum appears to be an obligate symbiont on the archaeon Ignicoccus; it must be in contact with the host organism to survive. Nanoarchaeum equitans cannot synthesize lipids but obtains them from its host. Its cells are only 400 nm in diameter, making it the smallest known living organism, and the smallest known archaeon.
Nanoarchaeota is a proposed phylum in the domain Archaea that currently has only one representative, Nanoarchaeum equitans, which was discovered in a submarine hydrothermal vent and first described in 2002.
Karl Otto Stetter is a German microbiologist and authority on astrobiology. Stetter is an expert on microbial life at high temperatures.
Archaeoglobaceae are a family of the Archaeoglobales. All known genera within the Archaeoglobaceae are hyperthermophilic and can be found near undersea hydrothermal vents. Archaeoglobaceae are the only family in the order Archaeoglobales, which is the only order in the class Archaeoglobi.
Archaeoglobus is a genus of the phylum Euryarchaeota. Archaeoglobus can be found in high-temperature oil fields where they may contribute to oil field souring.
Ferroglobus is a genus of the Archaeoglobaceae.
Methanococcus is a genus of coccoid methanogens of the family Methanococcaceae. They are all mesophiles, except the thermophilic M. thermolithotrophicus and the hyperthermophilic M. jannaschii. The latter was discovered at the base of a “white smoker” chimney at 21°N on the East Pacific Rise and it was the first archaeal genome to be completely sequenced, revealing many novel and eukaryote-like elements.
Pyrobaculum is a genus of the Thermoproteaceae.
In taxonomy, Vulcanisaeta is a genus of the Thermoproteaceae.
Sulfurisphaera is a genus of the Sulfolobaceae.
In taxonomy, Palaeococcus is a genus of the Thermococcaceae.
In taxonomy, Thermococcus is a genus of thermophilic Archaea in the family the Thermococcaceae.
Pyrodictium is a genus in the family Pyrodictiaceae. It is a genus of submarine hyperthermophilic Archaea whose optimal growth temperature range is 80 to 105 °C. They have a unique cell structure involving a network of cannulae and flat, disk-shaped cells. Pyrodictium are found in the porous walls of deep-sea vents where the temperatures inside get as high as 400 °C, while the outside marine environment is typically 3 °C. Pyrodictium is apparently able to adapt morphologically to this type of hot–cold habitat.
Halopiger is a genus of archaeans in the family Natrialbaceae that have high tolerance to salinity.
Natronorubrum is a genus in the family Halobacteriaceae.
Icerudivirus is a genus of viruses in the family Rudiviridae. These viruses are non-enveloped, stiff-rod-shaped viruses with linear dsDNA genomes, that infect hyperthermophilic archaea of the species Sulfolobus islandicus. There are three species in the genus.
Archaea is a domain of organisms. Traditionally, Archaea only included its prokaryotic members, but this sense has been found to be paraphyletic, as eukaryotes are now known to have evolved from archaea. Even though the domain Archaea includes eukaryotes, the term "archaea" in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially classified as bacteria, receiving the name archaebacteria, but this term has fallen out of use.
Thermococcus kodakarensis is a species of thermophilic archaea. The type strain T. kodakarensis KOD1 is one of the best-studied members of the genus.