Thermophile

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 122 °C (113 and 252 °F).[1][2] Many thermophiles are archaea. Thermophilic eubacteria are suggested to have been among the earliest bacteria.[3]

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.

Unlike other types of bacteria, thermophiles can survive at much hotter temperatures, whereas other bacteria would be damaged and sometimes killed if exposed to the same temperatures.

Professor Zachary Studniberg, from Cambridge University, wrote in his book 'The Function of Extremophiles' that they are the most unique organism on the planet in terms of their contribution to modern life.

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

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

Contents

  • Classification 1
  • Thermophile versus mesophile 2
  • Gene transfer and genetic exchange 3
  • See also 4
  • References 5
  • External links 6

Classification

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.

Bacteria within the acidophilic thermophiles, which can cause contamination in fruit juice drinks.[4]

A colony of thermophiles in the outflow of Mickey Hot Springs, Oregon, the water temperature is approximately 60°C.

Thermophiles, meaning heat-loving, 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°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 use thermophilic enzymes because of their ability to withstand intense heat.

Many of the hyperthermophiles Archea require elemental photosynthetic pigments.

Thermophile versus mesophile

Thermophiles can be discriminated from mesophiles from genomic features. For example, the GC content levels in the coding regions of some signatures genes were consistently identified as correlated with the temperature range condition when the association analysis was applied to mesophilic and thermophilic organisms regardless of their phylogeny, oxygen requirement, salinity, or habitat conditions.[5]

Gene transfer and genetic exchange

Sulfolobus solfataricus and Sulfolobus acidocaldarius are hyperthermophilic archaea. When these organisms are exposed to the DNA damaging agents UV irradiation, bleomycin or mitomycin C, species-specific cellular aggregation is induced.[6][7] In S. acidocaldarius, UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency.[7] Recombination rates exceed those of uninduced cultures by up to three orders of magnitude. Frols et al.[6][8] and Ajon et al. [7](2011) hypothesized that cellular aggregation enhances species-specific DNA transfer between Sulfolobus cells in order to provide increased repair of damaged DNA by means of homologous recombination. Van Wolferen et al.,[9] in discussing DNA exchange in the hyperthermophiles under extreme conditions, noted that DNA exchange likely plays a role in repair of DNA via homologous recombination. They suggested that this process is crucial under DNA damaging conditions such as high temperature. Also it has been suggested that DNA transfer in Sulfolobus may be a primitive form of sexual interaction similar to the more well-studied bacterial transformation systems that are associated with species-specific DNA transfer between cells leading to homologous recombinational repair of DNA damage [see Transformation (genetics)].

See also

References

  1. ^ Madigan MT, Martino JM (2006). Brock Biology of Microorganisms (11th ed.). Pearson. p. 136.  
  2. ^ Takai T, et al. (2008). production by a hyperthermophilic methanogen under high-pressure cultivation"4"Cell proliferation at 122°C and isotopically heavy CH. PNAS 105 (31): 10949–51.  
  3. ^ Horiike T, Miyata D, Hamada K, et al. (January 2009). "Phylogenetic construction of 17 bacterial phyla by new method and carefully selected orthologs". Gene 429 (1–2): 59–64.  
  4. ^ G. L. Pettipher, M. E. Osmundson, J. M. Murphy. Methods for the detection and enumeration of Alicyclobacillus acidoterrestris and investigation of growth and production of taint in fruit juice and fruit juice-containing drinks. Letters in Applied Microbiology. Volume 24, Issue 3, pages 185–189, March 1997.
  5. ^ Zheng H, Wu H (December 2010). "Gene-centric association analysis for the correlation between the guanine-cytosine content levels and temperature range conditions of prokaryotic species". BMC Bioinformatics 11: S7.  
  6. ^ a b >Fröls S, Ajon M, Wagner M, Teichmann D, Zolghadr B, Folea M, Boekema EJ, Driessen AJ, Schleper C, Albers SV (November 2008). "UV-inducible cellular aggregation of the hyperthermophilic archaeon Sulfolobus solfataricus is mediated by pili formation". Mol. Microbiol. 70 (4): 938–52.  
  7. ^ a b c Ajon M, Fröls S, van Wolferen M, Stoecker K, Teichmann D, Driessen AJ, Grogan DW, Albers SV, Schleper C (November 2011). "UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili". Mol. Microbiol. 82 (4): 807–17.  
  8. ^ Fröls S, White MF, Schleper C (February 2009). "Reactions to UV damage in the model archaeon Sulfolobus solfataricus". Biochem. Soc. Trans. 37 (Pt 1): 36–41.  
  9. ^ van Wolferen M, Ajon M, Driessen AJ, Albers SV (July 2013). "How hyperthermophiles adapt to change their lives: DNA exchange in extreme conditions". Extremophiles 17 (4): 545–63.  

External links

  • "Thermoprotei : Extreme Thermophile". NCBI Taxonomy Browser.