Thermophile

Thermophiles produce some of the bright colors of Grand Prismatic Spring, Yellowstone National Park

A thermophile is an organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 80 °C^[1] (113 and 176 °F). Many thermophiles are archaea.

Thermophiles are found in various geothermally heated regions of the Earth such as hot springs like those in Yellowstone National Park (see image) and deep sea hydrothermal vents, as well as decaying plant matter such as peat bogs and compost.

As a prerequisite for their survival, thermophiles contain enzymes that can function at high temperature. Some of these enzymes are used in molecular biology (for example, heat-stable DNA polymerases for PCR), and in washing agents.

Thermophiles are classified into obligate and facultative thermophiles: Obligate thermophiles (also called extreme thermophiles) require such high temperatures for growth, whereas facultative thermophiles (also called moderate thermophiles) can thrive at high temperatures but also at lower temperatures (below 50 °C). Hyperthermophiles are particularly extreme thermophiles for which the optimal temperatures are above 80 °C.

Thermophile is descended from the Greek: θερμότητα (thermotita), meaning heat, and Greek: φίλια (philia), love.

Extreme Thermophiles

Thermophiles, meaning heat-loving organisms, are organisms with an optimum growth temperature of 50 °C or more, a maximum of up to 70 °C or more, and a minimum of about 40 degrees C, but these are only approximate. Some extreme thermophiles (hyperthermophiles) require a very high temperature (80 °C to 105 °C) for growth. Their membranes and proteins are unusually stable at these extremely high temperatures. Thus many important biotechnological processes utilize thermophilic enzymes because of their ability to withstand intense heat.

Many of the hyperthermophiles Archea require elemental sulfur for growth. Some are anaerobes that use the sulfur instead of oxygen as an electron acceptor during cellular respiration. Some are lithotrophs that oxidize sulfur to sulfuric acid as an energy source, thus requiring the microorganism to be adapted to very low pH (i.e., it is an acidophile as well as thermophile). These organisms are inhabitants of hot, sulfur-rich environments usually associated with volcanism, such as hot springs, geysers, and fumaroles. In these places, especially in Yellowstone National Park, we find a zonation of microorganisms according to their temperature optima. Often these organisms are coloured, due to the presence of photosynthetic pigments.

Genomic and Proteomic Features of Thermophiles

The genome and proteome composition of thermophiles are characterized by overrepresentation of purine bases in protein coding sequences^[2], higher GC-content of the structural RNAs, distinct synonymous codon usage, enhanced usage of positively charged residues and aromatic residues, decrease in polar uncharged residues in the encoded protein.^[3]

See also

• Hyperthermophile
• Anaerobic digestion
• Mesophile
• Psychrophile

References

External links

• "Thermoprotei : Extreme Thermophile". NCBI Taxonomy Browser. http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=183924. 
• Major Groups Of Prokaryotes^{[dead link]}

v • d • e Extremophiles Categories Acidophile · Alkaliphile · Capnophile · Endolith · Halophile · Hyperthermophile · Hypolith · Lipophile  · Lithoautotroph · Lithophile  · Metalotolerant  · Oligotroph · Osmophile · Piezophile · Polyextremophile · Psychrophile · Thermophile · Thermoacidophile · Xerophile Notable extremophiles Bacteria Chloroflexus aurantiacus · Deinococcus radiodurans · Deinococcus-Thermus · Snottite · Thermus aquaticus · Thermus thermophilus · Spirochaeta americana Archaea Pyrococcus furiosus · Strain 121 Animalia Paralvinella sulfincola · Pompeii worm · Tardigrada Related articles Abiogenic petroleum origin · Acidithiobacillales · Acidobacteria · Acidophiles in acid mine drainage  · Archaeoglobaceae · Berkeley Pit · Blood Falls · Crenarchaeota · Grylloblattidae · Halobacteria · Halobacterium · Helaeomyia petrolei · Hydrothermal vent · Methanopyrus · Movile Cave · Radioresistance · Radiotrophic fungus  · Taq polymerase  · Thermostability · Thermotogae