Editing Microorganism (section)

==Discovery==
{{See also|History of biology|Microbiology#History}} 

===Ancient precursors===
[[File:Akshamsaddin's Tomb at Goynuk.jpg|thumb|upright=1.2|The mausoleum of [[Akshamsaddin]], who mentioned microorganisms in his book Maddat ul-Hayat in the 15th century, in Bolu, Turkiye.]]
[[File:Anthonie van Leeuwenhoek (1632-1723). Natuurkundige te Delft Rijksmuseum SK-A-957.jpeg|thumb|upright=0.8|[[Antonie van Leeuwenhoek]] was the first to study microscopic organisms.]]
[[File:Spallanzani.jpg|thumb|upright|[[Lazzaro Spallanzani]] showed that boiling a broth stopped it from decaying.]]

The possible existence of microscopic organisms was discussed for many centuries before their discovery in the 17th century. By the 6th century&nbsp;BC, the [[Jain]]s of present-day India postulated the existence of tiny organisms called ''[[nigoda]]s''.<ref name="JDL_2013">{{cite book |first=Jeffery D. |last=Long |title=Jainism: An Introduction |url=https://books.google.com/books?id=I3gAAwAAQBAJ&pg=PA100 |year=2013 |publisher=I.B.Tauris |isbn=978-0-85771-392-6 |page=100 }}</ref> These nigodas are said to be born in clusters; they live everywhere, including the bodies of plants, animals, and people; and their life lasts only for a fraction of a second.<ref>{{cite book |first=Upinder |last=Singh |title=A History of Ancient and Early Medieval India: From the Stone Age to the 12th Century |url=https://books.google.com/books?id=Pq2iCwAAQBAJ&pg=PA315 |year=2008 |publisher=Pearson Education India |isbn=978-81-317-1677-9 |page=315 }}</ref> According to [[Mahavira]], the 24th preacher of Jainism, the humans destroy these nigodas on a massive scale, when they eat, breathe, sit, and move.<ref name="JDL_2013"/> Many modern Jains assert that Mahavira's teachings presage the existence of microorganisms as discovered by modern science.<ref>{{cite book |first=Paul |last=Dundas |title=The Jains |url=https://books.google.com/books?id=X8iAAgAAQBAJ&pg=PA106 |year=2003 |publisher=Routledge |isbn=978-1-134-50165-6 |page=106 }}</ref>

The earliest known idea to indicate the possibility of diseases spreading by yet unseen organisms was that of the Roman scholar [[Marcus Terentius Varro]] in a 1st-century&nbsp;BC book entitled ''On Agriculture'' in which he called the unseen creatures animalia minuta, and warns against locating a homestead near a swamp:<ref name=Varro>''Varro on Agriculture'' 1, xii Loeb</ref>

{{blockquote|… and because there are bred certain minute creatures that cannot be seen by the eyes, which float in the air and enter the body through the mouth and nose and they cause serious diseases.<ref name=Varro/>}}

In ''[[The Canon of Medicine]]'' (1020), [[Avicenna]] suggested that [[tuberculosis]] and other diseases might be contagious.<ref>{{cite journal |last=Tschanz |first=David W. |title=Arab Roots of European Medicine |journal=Heart Views |volume=4 |issue=2 |url=http://www.hmc.org.qa/hmc/heartviews/h-v-v4%20n2/9.htm |url-status=dead |archive-url=https://web.archive.org/web/20110503050312/http://www.hmc.org.qa/hmc/heartviews/H-V-v4%20N2/9.htm |archive-date=3 May 2011 }}</ref><ref>{{cite book|title=Advice to the Young Physician: On the Art of Medicine|url={{google books |plainurl=y|id=DoMVs4HuDAoC|page=33}} |last=Colgan|first=Richard |page=33 |publisher=Springer |year=2009 |isbn=978-1-4419-1033-2}}</ref>

===Early modern===
{{More information|Microscopic discovery of bacteria}}

Turkish scientist [[Akshamsaddin]] mentioned the microbe in his work {{tlit|ota|Maddat ul-Hayat}} (The Material of Life) about two centuries prior to Leeuwenhoek's experimental discovery:
{{blockquote|It is a mistake to assume that diseases appear in individuals one by one. Diseases are transmitted from person to person. This transmission takes place through small seeds that are invisible to the eye, but are still alive.<ref>Taşköprülüzâde: ''Shaqaiq-e Numaniya'', v. 1, p. 48</ref><ref>Osman Şevki Uludağ: ''Beş Buçuk Asırlık Türk Tabâbet Tarihi'' (Five and a Half Centuries of Turkish Medical History). Istanbul, 1969, pp. 35–36</ref>}}

In [[1546 in science#Medicine|1546]], [[Girolamo Fracastoro]] proposed that [[epidemic diseases]] were caused by transferable seedlike entities that could transmit infection by direct or indirect contact, or even without contact over long distances.<ref>{{cite journal |last=Nutton |first=Vivian |title=The Reception of Fracastoro's Theory of Contagion: The Seed That Fell among Thorns? |journal=[[Osiris (journal)|Osiris]]|year=1990 |volume=2nd Series, Vol. 6, Renaissance Medical Learning: Evolution of a Tradition |pages=196–234 |jstor=301787 |doi=10.1086/368701|pmid=11612689 |s2cid=37260514 }}</ref>

[[Antonie van Leeuwenhoek]] is considered to be one of the [[List of people considered father or mother of a scientific field|fathers of microbiology]]. He was the first in 1673 to discover and conduct scientific experiments with microorganisms, using simple single-lensed [[Microscope|microscopes]] of his own design.<ref>{{Cite journal | last=Leeuwenhoek |first=A. | title=Part of a Letter from Mr Antony van Leeuwenhoek, concerning the Worms in Sheeps Livers, Gnats, and Animalcula in the Excrements of Frogs | journal=Philosophical Transactions | volume=22 | pages=509–518 | year=1753 | doi=10.1098/rstl.1700.0013 | issue=260–276 | bibcode=1700RSPT...22..509V | doi-access=free }}</ref><ref>{{Cite journal| last=Leeuwenhoek |first=A. |author-link=Antony van Leeuwenhoek | title=Part of a Letter from Mr Antony van Leeuwenhoek, F. R. S. concerning Green Weeds Growing in Water, and Some Animalcula Found about Them | journal=Philosophical Transactions | volume=23 | pages=1304–1311 |year=1753 | doi=10.1098/rstl.1702.0042 | issue=277–288 | bibcode=1702RSPT...23.1304V |s2cid=186209549 }}</ref><ref name="NickLane_RS">{{cite journal |author-link=Nick Lane |last=Lane |first=Nick |title=The Unseen World: Reflections on Leeuwenhoek (1677) 'Concerning Little Animal' |journal=Philos Trans R Soc Lond B Biol Sci |volume=370 |issue=1666 |pages=20140344 |year=2015 |doi=10.1098/rstb.2014.0344|pmid=25750239 |pmc=4360124 }}</ref><ref>Payne, A. S. ''The Cleere Observer: A Biography of Antoni Van Leeuwenhoek'', p. 13, Macmillan, 1970</ref> [[Robert Hooke]], a contemporary of Leeuwenhoek, also used [[microscopy]] to observe microbial life in the form of the fruiting bodies of [[Mold (fungus)|mould]]s. In his [[1665#July–December|1665]] book ''[[Micrographia]]'', he made drawings of studies, and he coined the term ''[[Cell (biology)|cell]]''.<ref>{{cite journal |last=Gest |first=H. |title=The remarkable vision of Robert Hooke (1635–1703): first observer of the microbial world |journal=Perspect. Biol. Med. |volume=48 |issue=2 |pages=266–272 |year=2005 |pmid=15834198 |doi=10.1353/pbm.2005.0053|s2cid=23998841 }}</ref>

===19th century===
[[File:Albert Edelfelt - Louis Pasteur - 1885.jpg|thumb|upright=0.8|left|[[Louis Pasteur]] showed that Spallanzani's findings held even if air could enter through a filter that kept particles out.]]

[[Louis Pasteur]] (1822–1895) exposed boiled broths to the air, in vessels that contained a filter to prevent particles from passing through to the [[growth medium]], and also in vessels without a filter, but with air allowed in via a curved tube so dust particles would settle and not come in contact with the broth. By boiling the broth beforehand, Pasteur ensured that no microorganisms survived within the broths at the beginning of his experiment. Nothing grew in the broths in the course of Pasteur's experiment. This meant that the living organisms that grew in such broths came from outside, as [[spore]]s on dust, rather than spontaneously generated within the broth. Thus, Pasteur refuted the theory of [[spontaneous generation]] and supported the [[germ theory of disease]].<ref>{{cite journal |last=Bordenave |first=G. |title=Louis Pasteur (1822–1895) |journal=Microbes Infect. |volume=5 |issue=6 |pages=553–560 |year=2003 |pmid=12758285 |doi=10.1016/S1286-4579(03)00075-3}}</ref>

[[File:Robert Koch.jpg|thumb|upright=0.8|[[Robert Koch]] showed that microorganisms caused [[disease]].]]

In 1876, [[Robert Koch]] (1843–1910) established that microorganisms can cause disease. He found that the blood of cattle that were infected with [[anthrax]] always had large numbers of ''[[Bacillus anthracis]]''. Koch found that he could transmit anthrax from one animal to another by taking a small sample of blood from the infected animal and injecting it into a healthy one, and this caused the healthy animal to become sick. He also found that he could grow the bacteria in a nutrient broth, then inject it into a healthy animal, and cause illness. Based on these experiments, he devised criteria for establishing a causal link between a microorganism and a disease and these are now known as [[Koch's postulates]].<ref>[http://nobelprize.org/nobel_prizes/medicine/laureates/1905/ The Nobel Prize in Physiology or Medicine 1905] Nobelprize.org Accessed 22 November 2006.</ref> Although these postulates cannot be applied in all cases, they do retain historical importance to the development of scientific thought and are still being used today.<ref>{{Cite journal |last=O'Brien |first=S. |last2=Goedert |first2=J. | title=HIV causes AIDS: Koch's postulates fulfilled | journal=Curr Opin Immunol | volume=8 | issue=5 | pages=613–618 | year=1996 | pmid=8902385 | doi=10.1016/S0952-7915(96)80075-6}}</ref>

The discovery of microorganisms such as ''[[Euglena]]'' that did not fit into either the [[animal]] or [[plant]] kingdoms, since they were [[photosynthetic]] like plants, but [[motile]] like animals, led to the naming of a third kingdom in the 1860s. In 1860 [[John Hogg (biologist)|John Hogg]] called this the [[Protoctista]], and in 1866 [[Ernst Haeckel]] named it the [[Protista]].<ref name=Scamardella1999>{{cite journal | last=Scamardella |first=J. M. | title=Not plants or animals: a brief history of the origin of Kingdoms Protozoa, Protista and Protoctista | year=1999 | journal=International Microbiology | volume=2 | issue=4 | pages=207–221 | pmid=10943416 | url=http://www.im.microbios.org/08december99/03%20Scamardella.pdf | access-date=1 October 2017 | archive-date=14 June 2011 | archive-url=https://web.archive.org/web/20110614000656/http://www.im.microbios.org/08december99/03%20Scamardella.pdf | url-status=dead }}</ref><ref name=Rothschild1989>{{cite journal |last=Rothschild |first=L. J. |author-link=Lynn J. Rothschild |title=Protozoa, Protista, Protoctista: what's in a name? |journal=J Hist Biol |volume=22 |issue=2 |pages=277–305 |year=1989 |pmid=11542176 |doi=10.1007/BF00139515 |s2cid=32462158 |url=https://zenodo.org/record/1232387 }}</ref><ref name=Pearl2005>{{cite book |editor1-first=Eldra Pearl |editor1-last=Solomon |editor2-first=Linda R. |editor2-last=Berg |editor3-first=Diana W. |editor3-last=Martin |chapter=Kingdoms or Domains? |chapter-url=https://books.google.com/books?id=qBOPoEc-zu4C&pg=PA421 |pages=421–7 |title=Biology |publisher=Brooks/Cole Thompson Learning |year=2005 |edition=7th |isbn=978-0-534-49276-2}}</ref>

The work of Pasteur and Koch did not accurately reflect the true diversity of the microbial world because of their exclusive focus on microorganisms having direct medical relevance. It was not until the work of [[Martinus Beijerinck]] and [[Sergei Winogradsky]] in the late 19th century that the true breadth of microbiology was revealed.<ref name=Brock>{{cite book | editor-last=Madigan |editor-first=M. |editor-last2=Martinko |editor-first2=J. | title=Brock Biology of Microorganisms | edition=13th | publisher=Pearson Education | year=2006 | isbn=978-0-321-73551-5 |page=1096}}</ref> Beijerinck made two major contributions to microbiology: the discovery of [[virus]]es and the development of [[enrichment culture]] techniques.<ref>{{cite web | last=Johnson |first=J. | title=Martinus Willem Beijerinck | work=APSnet| publisher=American Phytopathological Society | url=http://apsnet.org/education/feature/TMV/intro.html | archive-url=https://web.archive.org/web/20100620173433/http://apsnet.org/education/feature/TMV/intro.html | archive-date=2010-06-20 | year=2001 |orig-year=1998 | access-date=2 May 2010}} Retrieved from Internet Archive 12 January 2014.</ref> While his work on the [[tobacco mosaic virus]] established the basic principles of virology, it was his development of enrichment culturing that had the most immediate impact on microbiology by allowing for the cultivation of a wide range of microbes with wildly different physiologies. Winogradsky was the first to develop the concept of [[chemolithotrophy]] and to thereby reveal the essential role played by microorganisms in geochemical processes.<ref>{{cite book | last=Paustian |first=T. | last2=Roberts |first2=G. | chapter=Beijerinck and Winogradsky Initiate the Field of Environmental Microbiology | title=Through the Microscope: A Look at All Things Small | at=§&nbsp;1–14 | edition=3rd | year=2009 | publisher=Textbook Consortia | chapter-url=http://www.microbiologytext.com/index.php?module=Book&func=displayarticle&art_id=32 | access-date=3 October 2017 | archive-date=14 September 2008 | archive-url=https://web.archive.org/web/20080914000327/http://www.microbiologytext.com/index.php?module=Book&func=displayarticle&art_id=32 | url-status=dead }}</ref> He was responsible for the first isolation and description of both [[nitrifying bacteria|nitrifying]] and [[nitrogen-fixing bacteria]].<ref name=Brock /> French-Canadian microbiologist [[Félix d'Hérelle]] co-discovered [[bacteriophage]]s and was one of the earliest applied microbiologists.<ref name =Keen>{{cite journal |last=Keen |first=E. C. |title=Felix d'Herelle and Our Microbial Future |journal=Future Microbiology |volume=7 |issue=12 |pages=1337–1339 |year=2012 |pmid=23231482|doi=10.2217/fmb.12.115}}</ref>