Thermophile
A thermophile is an organism—a type of
Thermophiles are found in various
Thermophiles can survive at high temperatures, whereas other bacteria or archaea would be damaged and sometimes killed if exposed to the same temperatures.
The enzymes in thermophiles function at high temperatures. Some of these enzymes are used in molecular biology, for example the Taq polymerase used in PCR.[4] "Thermophile" is derived from the Greek: θερμότητα (thermotita), meaning heat, and Greek: φίλια (philia), love.
Comparative surveys suggest that thermophile diversity is principally driven by pH, not temperature.[5]
Classification
Thermophiles can be classified in various ways. One classification sorts these organisms according to their optimal growth temperatures:[6]
- Simple thermophiles: 50–64 °C (122–147 °F)
- Extreme thermophiles 65–79 °C (149–174 °F)
- Hyperthermophiles 80 °C (176 °F) and beyond, but not below 50 °C (122 °F)
In a related classification, thermophiles are sorted as follows:
- Facultative thermophiles (also called moderate thermophiles) can thrive at high temperatures, but also at lower temperatures (below 50 °C (122 °F)), whereas
- Obligate thermophiles (also called extreme thermophiles) require such high temperatures for growth.
- Hyperthermophiles are particularly extreme thermophiles for which the optimal temperatures are above 80 °C (176 °F).
Many of the hyperthermophilic Archaea require elemental
Thermophile versus mesophile
Thermophiles can be discriminated from mesophiles from genomic features. For example, the GC-content levels in the coding regions of some signature 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.[7]
Fungal thermophiles
Fungi are the only group of organisms in the Eukaryota domain that can survive at temperature ranges of 50–60 °C.[8] Thermophilic fungi have been reported from a number of habitats, with most of them belonging to the fungal order Sordariales.[9] Thermophilic fungi have great biotechnological potential due to their ability to produce industrial-relevant thermostable enzymes, in particular for the degradation of plant biomass.[10]
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.[11][12] In S. acidocaldarius, UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency.[12] Recombination rates exceed those of uninduced cultures by up to three orders of magnitude. Frols et al.[11][13] and Ajon et al.[12](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.,[14] 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[citation needed] (see Transformation (genetics)).
See also
References
- ISBN 0-13-196893-9.
- PMID 18664583.
- PMID 19000750.
- PMID 11238984.
- ^ Power, J.F., Carere, C.R., Lee, C.K., Wakerley, G.L., Evans, D.W., Button, M., White, D., Climo, M.D., Hinze, A.M., Morgan, X.C. and McDonald, I.R., 2018. Microbial biogeography of 925 geothermal springs in New Zealand. Nature communications, 9(1), p.2876.
- S2CID 36345694.
- PMID 21172057.
- S2CID 46013720.
- S2CID 224847697, retrieved 2022-06-02
- PMID 26615748.
- ^ PMID 18990182.
- ^ PMID 21999488.
- PMID 19143598.
- S2CID 5572901.
External links
- "Thermoprotei : Extreme Thermophile". NCBI Taxonomy Browser.
- How hot is too Hot? T-Limit Expedition