Schematic diagram of a Thermococcus gammatolerans cell

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. ...

, the Thermococci are a

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...

of microbes within the

Euryarchaeota Euryarchaeota (from Ancient Greek ''εὐρύς'' eurús, "broad, wide") is a phylum of archaea. Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extr ...

.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 of Health (NIH). It is approved and funded by the government of the United States. The ...

br>webpage on Thermococci
Data extracted from the They live in extremely hot environments, such as

hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspo ...

s, and they have optimal growth temperatures above 80 °C. ''

Thermococcus In taxonomy, ''Thermococcus'' is a genus of thermophilic Archaea in the family the Thermococcaceae. Members of the genus ''Thermococcus'' are typically irregularly shaped coccoid species, ranging in size from 0.6 to 2.0 μm in diameter. Some ...

'' and ''

Pyrococcus ''Pyrococcus'' is a genus of Thermococcaceaen archaean.See the NCBIbr>webpage on Pyrococcus Data extracted from the Description and significance ''Pyrococcus'' has similar characteristics of other thermoautotrophican archaea such as ''Ar ...

'' (literally "balls of fire") are both obligately

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: * Anaerobic adhesive, a bonding a ...

chemoorganotrophs. ''Thermococcus'' prefers 70-95 °C and ''Pyrococcus'' 70-100 °C. ''

Palaeococcus helgesonii ''Palaeococcus helgesonii'' is a hyperthermophillic, anaerobic yet microaerobic archaeon Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archae ...

'', recently discovered in the

Tyrrhenian Sea The Tyrrhenian Sea (; it, Mar Tirreno , french: Mer Tyrrhénienne , sc, Mare Tirrenu, co, Mari Tirrenu, scn, Mari Tirrenu, nap, Mare Tirreno) is part of the Mediterranean Sea off the western coast of Italy. It is named for the Tyrrhenian pe ...

, is an

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cel ...

chemoheterotrophic A Chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic ( chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototro ...

that grows at temperatures of 45-85 °C with an optimal temperature of 80 °C. ''

Thermococcus gammatolerans ''Thermococcus gammatolerans'' is an archaea extremophile and the most radiation-resistant organism known to exist. As reported in 2003 the type strain EJ3T was taken from a submarine hydrothermal vent in the Guaymas Basin off the coast of Baja ...

'' sp. nov. was recently discovered in the

Guaymas Basin The Guaymas Basin is a marginal rift basin, the largest such basin in the Gulf of California. It consists of two axial troughs (northern and southern). The basin results from the activity of one of the several spreading centers in the Gulf. The ...

, and it grows at temperatures from 55-95 °C with an optimal temperaturearound 88 °C with an optimal pH of 6. It has pronounced

radioresistance Radioresistance is the level of ionizing radiation that organisms are able to withstand. Ionizing-radiation-resistant organisms (IRRO) were defined as organisms for which the dose of acute ionizing radiation (IR) required to achieve 90% reducti ...

and can survive

gamma radiation A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically s ...

at 30 kGy.

References

External links

Archaea classes Euryarchaeota {{Euryarchaeota-stub

See also

References

Further reading

External links