''Thermoproteus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

archaea Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even thou ...

ns in the family

Thermoproteaceae Thermoproteaceae is a family (biology), family of archaeans in the order Thermoproteales. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnol ...

. These

prokaryotes A prokaryote (; less commonly spelled procaryote) is a single-celled organism whose cell lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Ancient Greek (), meaning 'before', and (), meaning 'nut' ...

are

thermophilic A thermophile is a type of extremophile that thrives at relatively high temperatures, between . Many thermophiles are archaea, though some of them are bacteria and fungi. Thermophilic eubacteria are suggested to have been among the earliest bact ...

sulphur-dependent organisms related to the genera ''

Sulfolobus ''Sulfolobus'' is a genus of microorganism in the family Sulfolobaceae. It belongs to the kingdom Thermoproteati of the Archaea domain. ''Sulfolobus'' species grow in volcanic springs with optimal growth occurring at pH 2–3 and temperatu ...

'', ''

Pyrodictium ''Pyrodictium'' is a genus in the family Pyrodictiaceae. It is a genus of submarine hyperthermophilic Archaea whose optimal growth temperature range is 80 to 110°C. They have a unique cell structure involving a network of cannulae and flat, di ...

'' and '' Desulfurococcus''. They are hydrogen-sulphur

autotrophs An autotroph is an organism that can convert abiotic sources of energy into energy stored in organic compounds, which can be used by other organisms. Autotrophs produce complex organic compounds (such as carbohydrates, fats, and proteins) us ...

and can grow at temperatures of up to 95 °C.

Description and significance

''Thermoproteus'' is a genus of anaerobes that grow in the wild by autotrophic sulfur reduction. Like other hyperthermophiles, ''Thermoproteus'' represents a living example of some of Earth's earliest organisms, located at the base of the Archaea.

Genome structure

Genetic sequencing of ''Thermoproteus'' has revealed much about the organism's modes of metabolism. Total genome length is 1.84 Mbp, and the DNA is double-stranded and circular. Genes are arranged in co-transcribed clusters called operons. The ''Thermoproteus tenax'' genome has been completely sequenced.

Phylogeny

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

(NCBI)

Cell structure and metabolism

A significant amount of research has been done on the metabolism of ''Thermoproteus'' and other hyperthermophiles as well. ''Thermoproteus'' metabolizes autotrophically through sulfur reduction, but it grows much faster by sulfur respiration in cultivation. In ''T. tenax'', a number of metabolic pathways allow the cell to select a mode of metabolism depending on the energy requirements of the cell (depending, for example, on the cell's developmental or growth stage). Like all archaea, ''Thermoproteus'' possesses unique membrane lipids, which are ether-linked glycerol derivatives of 20 or 40 carbon branched lipids. The lipids' unsaturations are generally conjugated (as opposed to the unconjugation found in Bacteria and Eukaryota). In ''Thermosphaera'', as in all members of the Crenarchaeota, the membranes are predominated by the 40-carbon lipids that span the entire membrane. This causes the membrane to be composed of monolayers with polar groups at each end. The cells are rod-shaped with diameters of up to 4 micrometres and up to 100 micrometres in length, and reproduce by developing branches on the end of the cell which grow into individual cells. They are motile by flagella.

Ecology

Members of ''Thermoproteus'' are found in acidic hot springs and water holes; they have been isolated in these habitats in Iceland, Italy, North America, New Zealand, the Azores, and Indonesia. Their optimal growth temperature is 85 °C.

References

External links

''Thermoproteus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Archaea genera Thermoproteota {{archaea-stub