Biology:Ignicoccus
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]
Systematics
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]
Cell structure
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]
Physiology
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]
Phylogeny
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_07_2026[7][8][9] | 53 marker proteins based GTDB 11-RS232[10][11][12] | |||||||||||||||||||||||||||||||||||||||||||||||||||
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See also
References
- ↑ 1.0 1.1 1.2 "Ignicoccus gen. nov., a novel genus of hyperthermophilic, chemolithoautotrophic Archaea, represented by two new species, Ignicoccus islandicus sp nov and Ignicoccus pacificus sp nov. and Ignicoccus pacificus sp. nov". International Journal of Systematic and Evolutionary Microbiology 50 (6): 2093–2100. November 2000. doi:10.1099/00207713-50-6-2093. PMID 11155984.
- ↑ 2.0 2.1 2.2 "A new phylum of Archaea represented by a nanosized hyperthermophilic symbiont". Nature 417 (6884): 63–67. 2 May 2002. doi:10.1038/417063a. PMID 11986665. Bibcode: 2002Natur.417...63H. https://www.nature.com/articles/417063a.
- ↑ 3.0 3.1 "A Complex Endomembrane System in the Archaeon Ignicoccus hospitalis Tapped by Nanoarchaeum equitans". Frontiers in Microbiology 8: 1072. 13 June 2017. doi:10.3389/fmicb.2017.01072. PMID 28659892.
- ↑ 4.0 4.1 "The ultrastructure of Ignicoccus: evidence for a novel outer membrane and for intracellular vesicle budding in an archaeon". Archaea 1 (1): 9–18. March 2002. doi:10.1155/2002/307480. PMID 15803654.
- ↑ Ignicoccus in LPSN; Freese, H. M.; Meier-Kolthoff, J. P.; Sardà Carbasse, J.; Afolayan, A. O.; Göker, M. (29 October 2025). "TYGS and LPSN in 2025: a Global Core Biodata Resource for genome-based classification and nomenclature of prokaryotes within DSMZ Digital Diversity". Nucleic Acids Research 53: D1–D12. doi:10.1093/nar/gkaf1110.
- ↑ C.L. Schoch. "Ignicoccus". National Center for Biotechnology Information (NCBI) taxonomy database. https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&mode=tree&id=54258&lvl=3.
- ↑ "The LTPlus". https://bioinfo.uib.es/ltp/#LTPlus.
- ↑ "LTP_all tree in newick format". https://biocom.uib.es/opucheck-backend/api/releases/07_26_04.
- ↑ Rossello-Mora, Ramon; Viver, Tomeu; Palmer-Rodríguez, Pere; Westram, Ralf; Bustos-Caparros, Esteban; Gago, Joan Francisco; Gonzalez-Mendez, Jaime; Llabrés, Mercè et al. (22 April 2026). "A pipeline for improved 16S rRNA gene-based phylogeny and diversity analyses of Bacteria and Archaea" (in en). Nature Portfolio. doi:10.21203/rs.3.rs-9370187/v1. https://doi.org/10.21203/rs.3.rs-9370187/v1.
- ↑ "GTDB release 11-RS232". https://gtdb.ecogenomic.org/about#4%7C.
- ↑ "ar53_r232.sp_label". https://data.gtdb.ecogenomic.org/releases/release232/232.0/auxillary_files/ar53_r232.sp_labels.tree.
- ↑ "Taxon History". https://gtdb.ecogenomic.org/taxon_history/.
Further reading
- "The unusual cell biology of the hyperthermophilic Crenarchaeon Ignicoccus hospitalis". Antonie van Leeuwenhoek 102 (2): 203–219. August 2012. doi:10.1007/s10482-012-9748-5. PMID 22653377. https://link.springer.com/article/10.1007/s10482-012-9748-5.
- "Three multihaem cytochromes c from the hyperthermophilic archaeon Ignicoccus hospitalis: purification, properties and localization". Microbiology 6 (160): 1278–1289. 2014. doi:10.1099/mic.0.077792-0. PMID 24705227.
External links
Wikidata ☰ Q290183 entry
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