In
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
, ''Thermoproteus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of the
Thermoproteaceae
In taxonomy, the Thermoproteaceae are a family of the Thermoproteales.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information
...
. These
prokaryotes
A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connec ...
are
thermophilic
A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...
sulphur-dependent organisms related to the genera ''
Sulfolobus
''Sulfolobus'' is a genus of microorganism in the family Sulfolobaceae. It belongs to the archaea domain.
''Sulfolobus'' species grow in volcanic springs with optimal growth occurring at pH 2-3 and temperatures of 75-80 °C, making them ...
'', ''
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 105°C. They have a unique cell structure involving a network of cannulae and flat, di ...
'' and ''
Desulfurococcus
In taxonomy, ''Desulfurococcus'' is a genus of the Desulfurococcaceae.See the NCBI
The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes ...
''. They are hydrogen-sulphur
autotrophs
An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", ...
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
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
Further reading
Scientific journals
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Scientific books
Scientific databases
External links
''Thermoproteus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Archaea genera
Thermoproteota
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