thermophile
{{short description|Organism that thrives at relatively high temperatures}}
{{distinguish|Thermopile|Thermopylae (disambiguation){{!}}Thermopylae}}
Image:Aerial image of Grand Prismatic Spring (view from the south).jpg, Yellowstone National Park]]
A thermophile is a type of extremophile that thrives at relatively high temperatures, between {{convert|41|and|122|C|F}}.{{cite book |title=Brock Biology of Microorganisms |date=2006|author=Madigan MT|author2=Martino JM |edition=11th |pages=136 |publisher=Pearson |isbn=0-13-196893-9}}{{Cite journal |author= Takai T |display-authors= etal |title=Cell proliferation at 122°C and isotopically heavy CH4 production by a hyperthermophilic methanogen under high-pressure cultivation |journal=PNAS |volume=105 |issue=31 |pages=10949–51 |date=2008 |doi= 10.1073/pnas.0712334105 |pmid=18664583 |pmc=2490668|bibcode=2008PNAS..10510949T |doi-access= free }} Many thermophiles are archaea, though some of them are bacteria and fungi. Thermophilic eubacteria are suggested to have been among the earliest bacteria.{{cite journal |author=Horiike T |author2=Miyata D |author3=Hamada K |display-authors=etal |title=Phylogenetic construction of 17 bacterial phyla by new method and carefully selected orthologs |journal=Gene |volume=429 |issue=1–2 |pages=59–64 |date=January 2009 |pmid=19000750 |pmc=2648810 |doi=10.1016/j.gene.2008.10.006 }}
Thermophiles are found in geothermally heated regions of the Earth, such as hot springs like those in Yellowstone National Park and deep sea hydrothermal vents, as well as decaying plant matter, such as peat bogs and compost. They 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.{{cite journal |last1=Vieille |first1=Claire |last2=Zeikus |first2=Gregory J. |date=March 2001 |title=Hyperthermophilic Enzymes: Sources, Uses, and Molecular Mechanisms for Thermostability |journal=Microbiology and Molecular Biology Reviews |volume=65 |issue=1 |pages=1–43 |doi=10.1128/MMBR.65.1.1-43.2001 |issn=1092-2172 |pmid=11238984|pmc=99017 }} "Thermophile" is derived from the {{langx|el|θερμότητα}} (thermotita), meaning heat, and {{langx|el|φίλια}} (philia), love.
Comparative surveys suggest that thermophile diversity is principally driven by pH, not temperature.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.
Classification
Thermophiles can be classified in various ways. One classification sorts these organisms according to their optimal growth temperatures:{{cite journal|author=Stetter, K.|title=History of discovery of the first hyperthermophiles|journal=Extremophiles|year=2006|volume=10|issue=5|pages=357–362|doi=10.1007/s00792-006-0012-7|pmid=16941067|s2cid=36345694}}
- Simple thermophiles: {{convert|50–64|C|F}}
- Extreme thermophiles {{convert|65–79|C|F}}
- Hyperthermophiles {{convert|80|C|F}} and beyond, but not below {{convert|50|C|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 {{convert|50|C}}), 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 {{convert|80|C}}.
File:Thermophilic bacteria.jpg, Oregon, the water temperature is approximately
{{convert|60|C}}.]]
Many hyperthermophilic Archaea require elemental sulfur for growth. Some are anaerobes that use the sulfur instead of oxygen as an electron acceptor during anaerobic cellular respiration. Some are lithotrophs that oxidize sulphur to create 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, zonation of microorganisms according to their temperature optima occurs. These organisms are often colored, due to the presence of photosynthetic pigments.{{cn|date=February 2023}}
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.{{cite journal |author=Zheng H |author2=Wu H |title=Gene-centric association analysis for the correlation between the guanine-cytosine content levels and temperature range conditions of prokaryotic species |journal=BMC Bioinformatics |volume=11 |pages=S7 |date=December 2010 |issue=Suppl 11 |doi=10.1186/1471-2105-11-S11-S7 |pmc=3024870 |pmid=21172057 |doi-access=free }}
Fungal thermophiles
Fungi are the only group of organisms in the Eukaryota domain that can survive at temperature ranges of 50–60 °C.{{Cite journal |last1=Rajasekaran |first1=A. K. |last2=Maheshwari |first2=R. |date=1993-09-01 |title=Thermophilic fungi: An assessment of their potential for growth in soil |url=https://doi.org/10.1007/BF02702992 |journal=Journal of Biosciences |language=en |volume=18 |issue=3 |pages=345–354 |doi=10.1007/BF02702992 |s2cid=46013720 |issn=0973-7138}} Thermophilic fungi have been reported from a number of habitats, with most of them belonging to the fungal order Sordariales.{{Citation |last1=Patel |first1=Hardi |title=Thermophilic fungi: Diversity, physiology, genetics, and applications |date=2021 |url=http://dx.doi.org/10.1016/b978-0-12-821005-5.00005-3 |work=New and Future Developments in Microbial Biotechnology and Bioengineering |pages=69–93 |publisher=Elsevier |access-date=2022-06-02 |last2=Rawat |first2=Seema|doi=10.1016/b978-0-12-821005-5.00005-3 |isbn=9780128210055 |s2cid=224847697 |url-access=subscription }} Thermophilic fungi have great biotechnological potential due to their ability to produce industrial-relevant thermostable enzymes, in particular for the degradation of plant biomass.{{Cite journal |last1=van den Brink |first1=Joost |last2=Facun |first2=Kryss |last3=de Vries |first3=Michel |last4=Stielow |first4=J. Benjamin |date=December 2015 |title=Thermophilic growth and enzymatic thermostability are polyphyletic traits within Chaetomiaceae |url=http://dx.doi.org/10.1016/j.funbio.2015.09.011 |journal=Fungal Biology |volume=119 |issue=12 |pages=1255–1266 |doi=10.1016/j.funbio.2015.09.011 |pmid=26615748 |bibcode=2015FunB..119.1255V |issn=1878-6146|url-access=subscription }}
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.{{cite journal |display-authors=6 |author=Fröls S |author2=Ajon M |author3=Wagner M |author4=Teichmann D |author5=Zolghadr B |author6= Folea M |author7=Boekema EJ |author8=Driessen AJ |author9=Schleper C |author10=Albers SV |title=UV-inducible cellular aggregation of the hyperthermophilic archaeon Sulfolobus solfataricus is mediated by pili formation |journal=Mol. Microbiol. |volume=70 |issue=4 |pages=938–52 |date=November 2008 |pmid=18990182 |doi=10.1111/j.1365-2958.2008.06459.x |url=https://www.rug.nl/research/portal/files/56956856/UV_inducible_cellular_aggregation_of_the_hyperthermophilic_archaeon_Sulfolobus_solfataricus_is_mediated_by_pili_formation.pdf |doi-access=free }}{{cite journal |author1=Ajon M |author2= Fröls S |author3=van Wolferen M |author4=Stoecker K |author5=Teichmann D |author6=Driessen AJ |author7=Grogan DW |author8=Albers SV |author9=Schleper C |display-authors=5 |title=UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili |journal=Mol. Microbiol. |volume=82 |issue=4 |pages=807–17 |date=November 2011 |pmid=21999488 |doi=10.1111/j.1365-2958.2011.07861.x |url=https://pure.rug.nl/ws/files/6771142/2011MolMicrobiolAjon.pdf |doi-access=free }} In S. acidocaldarius, UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency. Recombination rates exceed those of uninduced cultures by up to three orders of magnitude. Frols et al.{{cite journal |author=Fröls S |author2=White MF |author3=Schleper C |title=Reactions to UV damage in the model archaeon Sulfolobus solfataricus |journal=Biochem. Soc. Trans. |volume=37 |issue=Pt 1 |pages=36–41 |date=February 2009 |pmid=19143598 |doi=10.1042/BST0370036 }} and Ajon et al.(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., 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.{{cite journal |author=van Wolferen M |author2=Ajon M |author3=Driessen AJ |author4=Albers SV |title=How hyperthermophiles adapt to change their lives: DNA exchange in extreme conditions |journal=Extremophiles |volume=17 |issue=4 |pages=545–63 |date=July 2013 |pmid=23712907 |doi=10.1007/s00792-013-0552-6 |s2cid=5572901 }}
See also
References
{{reflist}}
External links
- {{cite web |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=183924 |title=Thermoprotei : Extreme Thermophile |work=NCBI Taxonomy Browser }}
- [https://deepcarbon.net/feature/how-hot-is-too-hot#.V9Fp-4WASfE/ How hot is too Hot? T-Limit Expedition]
{{Extremophile}}