Editing Microorganism (section)

==Ecology==
{{main |Microbial ecology}}

Microorganisms are found in almost every [[Habitat (ecology)|habitat]] present in nature, including hostile environments such as the [[Geographic poles|North and South poles]], [[desert]]s, [[geyser]]s, and [[Rock (geology)|rocks]]. They also include all the [[marine microorganism]]s of the [[World ocean|oceans]] and [[deep sea]]. Some types of microorganisms have adapted to [[extreme environment]]s and sustained colonies; these organisms are known as [[extremophiles]]. Extremophiles have been isolated from rocks as much as 7 kilometres below the Earth's surface,<ref>{{Cite journal |author=Szewzyk, U. |author2=Szewzyk, R. |author3=Stenström, T. | title=Thermophilic, anaerobic bacteria isolated from a deep borehole in granite in Sweden | doi= 10.1073/pnas.91.5.1810 | journal=PNAS | volume=91 | issue=5 | pages=1810–1813 | year=1994 | pmid=11607462 | pmc=43253 | bibcode=1994PNAS...91.1810S|doi-access=free }}</ref> and it has been suggested that the amount of organisms living below the Earth's surface is comparable with the amount of life on or above the surface.<ref name=Gold/> Extremophiles have been known to survive for a prolonged time in a [[vacuum]], and can be highly resistant to [[ultraviolet radiation|radiation]], which may even allow them to survive in space.<ref>{{Cite journal| author=Horneck, G. | title=Survival of microorganisms in space: a review | journal=Adv Space Res | volume=1 | issue=14 | pages=39–48 | year=1981|pmid=11541716 | doi=10.1016/0273-1177(81)90241-6}}</ref> Many types of microorganisms have intimate [[symbiosis|symbiotic relationships]] with other larger organisms; some of which are mutually beneficial ([[Mutualism (biology)|mutualism]]), while others can be damaging to the [[host (biology)|host]] organism ([[parasitism]]). If microorganisms can cause [[disease]] in a host they are known as ''[[pathogen]]s''. Microorganisms play critical roles in Earth's [[biogeochemical cycle]]s as they are responsible for [[decomposition]] and [[nitrogen fixation]].<ref>{{cite journal |last1=Rousk |first1=Johannes |last2=Bengtson |first2=Per |title=Microbial regulation of global biogeochemical cycles |journal=Frontiers in Microbiology |date=2014 |volume=5 |issue=2 |pages=210–225 |doi=10.3389/fmicb.2014.00103 |pmid=24672519 |pmc=3954078|doi-access=free }}</ref>

Bacteria use [[gene regulatory network|regulatory networks]] that allow them to adapt to almost every environmental niche on earth.<ref name= FillouxAAM>{{cite book | editor=Filloux, A. A. M. | year=2012 | title=Bacterial Regulatory Networks | publisher=[[Caister Academic Press]] | isbn= 978-1-908230-03-4}}</ref><ref name= GrossRBeierD>{{cite book | editor=Gross, R. |editor2=Beier, D. | year=2012 | title=Two-Component Systems in Bacteria | publisher=[[Caister Academic Press]] | isbn= 978-1-908230-08-9}}</ref> A network of interactions among diverse types of molecules including DNA, RNA, proteins and metabolites, is utilised by the bacteria to achieve [[regulation of gene expression]]. In bacteria, the principal function of regulatory networks is to control the response to environmental changes, for example nutritional status and environmental stress.<ref name= RequenaJM>{{cite book | editor=Requena, J. M. | year=2012 | title=Stress Response in Microbiology | publisher=[[Caister Academic Press]] | isbn=978-1-908230-04-1}}</ref> A complex organization of networks permits the microorganism to coordinate and integrate multiple environmental signals.<ref name="FillouxAAM"/>

===Extremophiles===
{{main|Extremophile}}
{{further|List of microorganisms tested in outer space}}
[[file:Deinococcus radiodurans.jpg|thumb|upright|A tetrad of ''[[Deinococcus radiodurans]]'', a [[radioresistant]] [[extremophile]] bacterium]]

[[Extremophiles]] are microorganisms that have adapted so that they can survive and even thrive in [[extreme environment]]s that are normally fatal to most life-forms. [[Thermophile]]s and [[hyperthermophiles]] thrive in high [[temperature]]s. [[Psychrophile]]s thrive in extremely low temperatures. – Temperatures as high as {{convert|130|°C|°F}},<ref>[[Strain 121]], a [[Hyperthermophile|hyperthermophilic]] [[archaea]], has been shown to reproduce at {{convert|121|°C|°F}}, and survive at {{convert|130|°C|°F}}.[https://www.nsf.gov/od/lpa/news/03/pr0384.htm]</ref> as low as {{convert|-17|°C|°F}}<ref>Some [[Psychrophiles|Psychrophilic]] bacteria can grow at {{convert|-17|°C|°F}}),[http://news.bbc.co.uk/1/hi/sci/tech/827063.stm] and can survive near [[absolute zero]]).{{cite web |title=Earth microbes on the Moon |url=https://science.nasa.gov/newhome/headlines/ast01sep98_1.htm |url-status=dead |archive-url=https://web.archive.org/web/20100323224432/http://science.nasa.gov/newhome/headlines/ast01sep98_1.htm |archive-date=23 March 2010 |access-date=2009-07-20}}</ref> [[Halophile]]s such as ''[[Halobacterium salinarum]]'' (an archaean) thrive in high [[Salinity|salt conditions]], up to saturation.<ref>Dyall-Smith, Mike, [http://www.microbiol.unimelb.edu.au/people/dyallsmith/ ''HALOARCHAEA''], University of Melbourne. See also [[Haloarchaea]].</ref> [[Alkaliphile]]s thrive in an [[alkaline]] [[pH]] of about 8.5–11.<ref>{{Cite journal|url=http://jb.asm.org/cgi/reprint/185/2/461.pdf|title=''Bacillus alcalophilus'' can grow at up to pH 11.5|journal=Journal of Bacteriology|date=15 January 2003|volume=185|issue=2|pages=461–465|doi=10.1128/JB.185.2.461-465.2003|last1=Olsson|first1=Karen|last2=Keis|first2=Stefanie|last3=Morgan|first3=Hugh W.|last4=Dimroth|first4=Peter|last5=Cook|first5=Gregory M.|pmid=12511491|pmc=145327}}</ref> [[Acidophile]]s can thrive in a pH of 2.0 or less.<ref>[[Picrophilus]] can grow at pH −0.06.[http://www.rcn.montana.edu/resources/organisms/organisminfo.aspx?nav=11&tid=1298&did=1&nid=82076&lid=9] {{Webarchive|url=https://web.archive.org/web/20100622184325/http://www.rcn.montana.edu/resources/organisms/organisminfo.aspx?nav=11&tid=1298&did=1&nid=82076&lid=9|date=22 June 2010}}</ref> [[Piezophile]]s thrive at very [[high pressure]]s: up to 1,000–2,000 [[Atmosphere (unit)|atm]], down to 0 atm as in a [[vacuum]] of [[Outer space|space]].{{efn|The [[Piezophile|piezophilic]] bacteria [[Halomonas salaria]] requires a pressure of 1,000 atm; [[nanobes]], a speculative organism, have been reportedly found in the earth's crust at 2,000 atm.<ref>{{cite web | url=http://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/nanobes/nanopaper.html | title=Microscopy-UK Home (Resources for the microscopy enthusiast and amateur, including free monthly e-zine, Micscape.) }}</ref>}} A few extremophiles such as ''[[Deinococcus radiodurans]]'' are [[radioresistance|radioresistant]],<ref>{{cite journal | volume=10 | issue=1 | pages=575–577 | last=Anderson | first=A. W. |author2=Nordan, H. C. |author3=Cain, R. F. |author4=Parrish, G. |author5=Duggan, D. | title=Studies on a radio-resistant micrococcus. I. Isolation, morphology, cultural characteristics, and resistance to gamma radiation | journal=Food Technol. | year=1956}}</ref> resisting [[Ionizing radiation|radiation]] exposure of up to 5k [[Gray (unit)|Gy]]. Extremophiles are significant in different ways. They extend terrestrial life into much of the Earth's [[hydrosphere]], [[Crust (geology)|crust]] and [[atmosphere]], their specific evolutionary adaptation mechanisms to their extreme environment can be exploited in [[biotechnology]], and their very existence under such extreme conditions increases the potential for [[extraterrestrial life]].<ref>{{cite journal |author=Cavicchioli, R. |title=Extremophiles and the search for extraterrestrial life |journal=Astrobiology |volume=2 |issue=3 |pages=281–292 |year=2002 |pmid=12530238 |doi=10.1089/153110702762027862 |bibcode=2002AsBio...2..281C |url=http://somosbacteriasyvirus.com/extremophiles.pdf |citeseerx=10.1.1.472.3179 |access-date=26 October 2017 |archive-date=26 April 2022 |archive-url=https://web.archive.org/web/20220426071811/https://somosbacteriasyvirus.com/extremophiles.pdf |url-status=dead }}</ref>

===Plants and soil===
{{Main |Soil biology}}

The [[nitrogen cycle]] in soils depends on the [[nitrogen fixation|fixation of atmospheric nitrogen]]. This is achieved by a number of [[diazotroph]]s. One way this can occur is in the [[root nodule]]s of [[legumes]] that contain symbiotic [[bacteria]] of the genera ''[[Rhizobium]]'', ''[[Mesorhizobium]]'', ''[[Sinorhizobium]]'', ''[[Bradyrhizobium]]'', and ''[[Azorhizobium]]''.<ref>{{Cite journal |author=Barea, J. |author2=Pozo, M. |author3=Azcón, R. |author4=Azcón-Aguilar, C. | title=Microbial co-operation in the rhizosphere | doi= 10.1093/jxb/eri197 | journal=J Exp Bot | volume=56 | issue=417 | pages=1761–1778 | year=2005 | pmid=15911555| doi-access=free }}</ref>

The [[root]]s of plants create a narrow region known as the [[rhizosphere]] that supports many microorganisms known as the [[root microbiome]].<ref name="Gottel">{{Cite journal|doi=10.1128/AEM.05255-11|pmid=21764952|pmc=3165402|title=Distinct Microbial Communities within the Endosphere and Rhizosphere of Populus deltoides Roots across Contrasting Soil Types|journal=Applied and Environmental Microbiology|volume=77|issue=17|pages=5934–5944|year=2011|last1=Gottel|first1=Neil R.|last2=Castro|first2=Hector F.|last3=Kerley|first3=Marilyn|last4=Yang|first4=Zamin|last5=Pelletier|first5=Dale A.|last6=Podar|first6=Mircea|last7=Karpinets|first7=Tatiana|last8=Uberbacher|first8=Ed|last9=Tuskan|first9=Gerald A.|last10=Vilgalys|first10=Rytas|last11=Doktycz|first11=Mitchel J.|last12=Schadt|first12=Christopher W.|bibcode=2011ApEnM..77.5934G}}</ref>

These microorganisms in the [[root microbiome]] are able to interact with each other and surrounding plants through signals and cues. For example, [[mycorrhizal fungi]] are able to communicate with the root systems of many plants through chemical signals between both the plant and fungi. This results in a mutualistic [[symbiosis]] between the two. However, these signals can be eavesdropped by other microorganisms, such as the [[soil bacteria]], ''Myxococcus xanthus'', which preys on other bacteria. Eavesdropping, or the interception of signals from unintended receivers, such as plants and microorganisms, can lead to large-scale, evolutionary consequences. For example, signaler-receiver pairs, like plant-microorganism pairs, may lose the ability to communicate with neighboring populations because of variability in eavesdroppers. In adapting to avoid local eavesdroppers, signal divergence could occur and thus, lead to the isolation of plants and microorganisms from the inability to communicate with other populations.<ref>{{Cite journal| last  = Rebolleda-Gómez |first=M. |last2=Wood |first2=C. W. |title=Unclear Intentions: Eavesdropping in Microbial and Plant Systems |journal=Frontiers in Ecology and Evolution |year=2019 | volume=7 |issue=385|doi=10.3389/fevo.2019.00385 |doi-access=free }}</ref>

===Symbiosis===
[[File:Hyella caespitosa.jpg|thumb|right|The photosynthetic [[cyanobacterium]] ''Hyella caespitosa'' (round shapes) with fungal hyphae (translucent threads) in the [[lichen]] ''Pyrenocollema halodytes'']]
A [[lichen]] is a [[symbiosis]] of a macroscopic fungus with [[photosynthetic]] microbial [[alga]]e or [[cyanobacteria]].<ref>{{cite web |url=https://www.anbg.gov.au/lichen/what-is-lichen.html |title=What is a lichen? |publisher=Australian National Botanic Gardens |access-date=30 September 2017}}</ref><ref>{{cite web |url=http://www.ucmp.berkeley.edu/fungi/lichens/lichens.html |title=Introduction to Lichens – An Alliance between Kingdoms |publisher=University of California Museum of Paleontology |access-date=30 September 2017}}</ref>