Hyperthermophile

Hyperthermophile

A hyperthermophile is an organism that thrives in extremely hot environments— from 60 degrees Celsius (140 degrees Fahrenheit) upwards. An optimal temperature for the existence of Hypothermophiles are above 80°C (176°F). Hyperthermophiles are a subset of extremophiles, micro-organisms within the domain Archaea, although some bacteria are able to tolerate temperatures of around 100°C (212°F), too. Many hyperthermophiles are also able to withstand other environmental extremes such as high acidity or radiation levels.

History

Hyperthermophiles were first discovered in the 1960s, in hot springs in Yellowstone National Park, Wyoming. Since then, more than fifty species have been discovered. The most hardy hyperthermophiles yet discovered live on the superheated walls of deep-sea hydrothermal vents, requiring temperatures of at least 90°C for survival. The most heat-tolerant hyperthermophile is the recently-discovered "Strain 121" [http://www.astrobiology.com/news/viewpr.html?pid=12337 Microbe from depths takes life to hottest known limit] ] which has been able to double its population during 24 hours in an autoclave at 121°C (hence its name).

Although no hyperthermophile has yet been discovered living at temperatures above 121°C, their existence is very possible (Strain 121 survived being heated to 130°C for two hours, but was not able to reproduce until it had been transferred into a fresh growth medium, at a relatively-cooler 103°C). However, it is thought unlikely that microbes could survive at temperatures above 150°C, as the cohesion of DNA and other vital molecules begins to break down at this point.

Research

Early research into hyperthermophiles speculated that their genomes could be characterized by high guanine-cytosine content; however, recent studies show that "there is no obvious correlation between the GC content of the genome and the optimal environmental growth temperature of the organism." [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1088632 High guanine-cytosine content is not an adaptation to high temperature: a comparative analysis amongst prokaryotes ] ]

The protein molecules in the hyperthermophiles exhibit hyperthermostability—that is, they can maintain structural stability (and therefore function) at high temperatures. Such proteins are homologous to their functional analogues in organisms which thrive at lower temperatures, but have evolved to exhibit optimal function at much greater temperatures. Most of the low-temperature homologues of the hyperthermostable proteins would be denatured above 60°C. Such hyperthermostable proteins are often commercially important, as chemical reactions proceed faster at high temperatures. The genomic signature of hyperthermophilic adaptation is characterized by the overrepresentation of purine bases in protein coding sequences and higher GC-content in tRNA/rRNA sequences. [ [http://www.biomedcentral.com/1471-2164/7/186 "Analysis of Nanoarchaeum equitans genome and proteome composition: indications for hyperthermophilic and parasitic adaptation."] ]

pecific hyperthermophiles

* "Methanopyrus kandleri" Strain 116, an Archaea in 80–122°C in a Central Indian Ridge.
* Strain 121, an Archaea living at 121°C in the Pacific.
* "Pyrolobus fumarii", an Archaea living at 113°C in Atlantic hydrothermal vents.
* "Pyrococcus furiosus", an Archaea which thrives at 100°C, first discovered in Italy near a volcanic vent.
* "Geothermobacterium ferrireducens", Bacteria which thrive in 65–100°C in Obsidian Pool, Yellowstone National Park.
* "Aquifex aeolicus", Bacteria living at 85–95°C in Yellowstone National Park.

References

*
*

ee also

* Mesophile
* Thermophile


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • hyperthermophile — noun Date: 1988 an organism that lives in extremely hot environments (as hot springs) with temperatures around the boiling point of water • hyperthermophilic adjective …   New Collegiate Dictionary

  • Hyperthermophile — Organisme thermophile Les organismes thermophiles (du grec thermê, chaleur et philein, aimer) ou hyperthermophiles sont des organismes qui ont besoin d une température élevée pour vivre. Ils font partie des organismes extrémophiles. Les… …   Wikipédia en Français

  • hyperthermophile — (hi per ther mo fīl) A bacterium that has its growth optimum between 80ºC and about 113ºC. Hyperthermophiles usually do not grow well below 55ºC …   Dictionary of microbiology

  • hyperthermophile — Members of the Archaea that live and thrive in temperatures above 60°C, sometimes above 100°C (cf. thermophiles, which have a tolerance ceiling of about 60°C) …   Dictionary of molecular biology

  • hyperthermophile — noun an organism that lives and thrives in an extremely hot environment, such as a deep sea smoker vent; often a member of the Archaea See Also: hyperthermophilic, thermophile …   Wiktionary

  • hyperthermophile — hy·per·thermophile …   English syllables

  • hyperthermophile — …   Useful english dictionary

  • Prefoldin — [ http://www.pdb.org/pdb/explore.do?structureId=1FXK more details...] )] IntroductionPrefoldin is a family of proteins used in protein folding complexes. It is classified as a heterohexameric molecular chaperone in both archaea and eukarya,… …   Wikipedia

  • Thermophile — A thermophile is an organism mdash; a type of extremophile mdash; which at relatively high temperatures, between 45 and 80 °C [cite book |title=Brock Biology of Microorganisms | year=2006| author=Madigan MT, Martino JM | edition=11th ed.… …   Wikipedia

  • Archaea — Archaeen Archaeon des Genus Sulfolobus, infiziert mit dem Sulfolobus Virus STSV1. Maßstab = 1 μm. Systematik Klassifikation …   Deutsch Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”