View source for Nanobacterium

{{Short description|Genus of bacteria}}
{{italic title}}
{{Taxobox
| name = "''Nanobacterium''"
| domain = [[Bacteria]]
| phylum = [[Pseudomonadota]]
| classis = [[Alphaproteobacteria]]
| ordo = ''[[incertae sedis]]''
| familia = ''[[incertae sedis]]''
| genus = '''"''Nanobacterium''"'''
| genus_authority = Ciftcioglu et al. 1997<ref>{{cite book |vauthors = Ciftcioglu N, Kuronen I, Åkerman K, Hiltunen E, Laukkanen J, Kajander EO | chapter = A new potential threat in antigen and antibody products: Nanobacteria |veditors= Brown F, Burton D, Doherty P, Mekalanos J, Norrby E | title = Vaccines 97. Molecular approaches to the control of infectious diseases | publisher = Cold Spring Harbor Laboratory Press | location = New York | date= 1997 | pages = 99–103 | isbn = 0-87969-516-1}}</ref>
| subdivision_ranks = Species
| subdivision = 
* "''[[Nanobacterium sanguineum]]''" <small>Ciftcioglu et al. 1997</small>
| synonyms =
}}
[[Image:ALH84001 structures.jpg|thumb|Structures found on meteorite fragment [[Allan Hills 84001]]]]

'''''Nanobacterium''''' ({{IPAc-en|ˌ|n|æ|n|oʊ|b|æ|k|ˈ|t|ɪər|i|əm}} {{respell|NAN|oh|bak|TEER|ee|əm}}, pl. ''nanobacteria'' {{IPAc-en|ˌ|n|æ|n|oʊ|b|æ|k|ˈ|t|ɪər|i|ə}} {{respell|NAN|oh|bak|TEER|ee|ə}}) is the unit or member name of a former proposed class of living [[organism]]s, specifically [[cell wall|cell-walled]] [[microorganisms]], now discredited, with a size much smaller than the generally accepted lower limit for life (about 200&nbsp;[[nanometer|nm]] for [[Bacteria#Morphology|bacteria]], like [[Mycoplasma pneumoniae#Cell biology|mycoplasma]]). Originally based on observed nano-scale structures in geological formations (including the Martian meteorite [[Allan Hills 84001]]), the status of nanobacteria was controversial, with some researchers suggesting they are a new class of living organism<ref>{{cite journal |author=Kajander E |title=Nanobacteria—propagating calcifying nanoparticles |journal=Lett Appl Microbiol |volume=42 |issue=6 |pages=549–52 |year=2006 |pmid=16706890 |doi=10.1111/j.1472-765X.2006.01945.x|s2cid=20169194 |doi-access= }}</ref><ref>{{cite journal |vauthors=Ciftcioglu N, McKay D, Mathew G, Kajander E |title=Nanobacteria: fact or fiction? Characteristics, detection, and medical importance of novel self-replicating, calcifying nanoparticles |journal=J Investig Med |volume=54 |issue=7 |pages=385–94 |year=2006 |pmid=17169260 |doi=10.2310/6650.2006.06018|s2cid=35400477 |hdl=2060/20060028181 |hdl-access=free }}</ref> capable of incorporating radiolabeled [[uridine]],<ref name="mayo1" /> and others attributing to them a simpler, [[abiotic]] nature.<ref name=Cisar /><ref name="Martel J, Young JD 2008 5549–54">{{cite journal |vauthors=Martel J, Young JD |title=Purported nanobacteria in human blood as calcium carbonate nanoparticles |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=105 |issue=14 |pages=5549–54 |date=April 2008 |pmid=18385376 |doi=10.1073/pnas.0711744105 |pmc=2291092 |bibcode = 2008PNAS..105.5549M |doi-access=free }}</ref> One skeptic dubbed them "the [[cold fusion]] of microbiology", in reference to a notorious episode of supposed erroneous science.<ref>Jack Maniloff, quoted in "The Rise and Fall of Nanobacteria", Young and Martel, ''Scientific American'', January 2010</ref> The term "calcifying [[nanoparticle]]s" (CNPs) has also been used as a conservative name regarding their possible status as a life form.

Research tends to agree that these structures exist, and appear to replicate in some way.<ref>{{cite journal|pmc=2242841|title=Nanobacteria Are Mineralo Fetuin Complexes|year=2008|volume=4|issue=2|pmid=18282102|last1=Raoult|first1=D|last2=Drancourt|first2=M|last3=Azza|first3=S|last4=Nappez|first4=C|last5=Guieu|first5=R|last6=Rolain|first6=JM|last7=Fourquet|first7=P|last8=Campagna|first8=B|last9=La Scola|first9=B|last10=Mege|first10=Jean-Louis|last11=Mansuelle|first11=Pascal|last12=Lechevalier|first12=Eric|last13=Berland|first13=Yvon|last14=Gorvel|first14=Jean-Pierre|last15=Renesto|first15=Patricia|pages=e41|doi=10.1371/journal.ppat.0040041|journal=PLOS Pathogens|display-authors=8 |doi-access=free }}</ref> However, the idea that they are living entities has now largely been discarded, and the particles are instead thought to be nonliving crystallizations of minerals and organic molecules.<ref>"The Rise and Fall of Nanobacteria", Young and Martel, ''Scientific American'', January 2010</ref>

==1981–2000==
In 1981 Francisco Torella and Richard Y. Morita described very small cells called [[ultramicrobacteria]].<ref>{{cite journal |last1=Torella |first1=Francisco |last2=Morita |first2=Richard Y. |title=Microcultural Study of Bacterial Size Changes and Microcolony and Ultramicrocolony Formation by Heterotrophic Bacteria in Seawater |journal=Appl. Environ. Microbiol. |date=1 February 1981 |volume=41 |issue=2 |pages=518–527 |doi=10.1128/aem.41.2.518-527.1981 |pmid=16345721 |pmc=243725 |bibcode=1981ApEnM..41..518T }}</ref> Defined as being smaller than 300&nbsp;nm, by 1982 MacDonell and Hood found that some could pass through a 200&nbsp;nm membrane{{Citation needed|date=April 2023}}. Early in 1989, geologist [[Robert L. Folk]] found what he later identified as ''nannobacteria'' (written with double "n"), that is, nanoparticles isolated from geological specimens<ref>A convention has been adopted between researchers to name -or spell- the nanoparticles isolated from geological specimens as ''nannobacteria'', and those from biological specimens as ''nanobacteria''.</ref> in [[travertine]] from hot springs of [[Viterbo]], Italy.  Initially searching for a bacterial cause for travertine deposition, [[scanning electron microscope]] examination of the mineral where no bacteria were detectable revealed extremely small objects which appeared to be biological.<!-- 1989 find: Dark Life, pg 44 -->  His first oral presentation elicited what he called "mostly a stony silence", at the 1992 [[Geological Society of America]]'s annual convention.<ref name="Folk1997">{{cite web|url=http://naturalscience.com/ns/articles/01-03/ns_folk.html|title=Nanobacteria: surely not figments, but what under heaven are they?|last=Folk|first=Robert L.|date=March 4, 1997|publisher=naturalSCIENCE|access-date=2008-12-20|url-status=dead|archive-url=https://web.archive.org/web/20081209035746/http://naturalscience.com/ns/articles/01-03/ns_folk.html|archive-date=December 9, 2008}}</ref> He proposed that nanobacteria are the principal agents of precipitation of all minerals and crystals on Earth formed in liquid water, that they also cause all oxidation of metals, and that they are abundant in many biological specimens.<ref name="Folk1997" />

In 1996, NASA scientist [[David S. McKay|David McKay]] published a study suggesting the existence of nanofossils — fossils of Martian nanobacteria — in [[ALH84001]], a meteorite originating from [[Mars]] and found in Antarctica.<ref name="life">{{cite journal |last=McKay |first=David S. |year=1996 |title=Search for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH84001 |journal=Science |volume=273 |issue=5277 |pages=924–930 |doi=10.1126/science.273.5277.924 |pmid=8688069 |bibcode=1996Sci...273..924M|s2cid=40690489 |display-authors=etal}}</ref>

''Nanobacterium sanguineum'' was proposed in 1998 as an explanation of certain kinds of pathologic [[calcification]] ([[apatite]] in [[kidney stone]]s) by [[Finland|Finnish]] researcher [[Olavi Kajander]] and [[Turkey|Turkish]] researcher [[Neva Çiftçioğlu]], working at the [[University of Kuopio]] in Finland. According to the researchers, the particles [[Self-replication|self-replicated]] in [[microbiological culture]], and the researchers further reported having identified [[DNA]] in these structures by staining.<ref name=Kajander>{{cite journal |vauthors=Kajander E, Ciftçioglu N |title=Nanobacteria: An alternative mechanism for pathogenic intra- and extracellular calcification and stone formation |journal=Proc Natl Acad Sci USA |volume=95 |issue=14 |pages=8274–9 |year=1998 |pmid=9653177 |doi=10.1073/pnas.95.14.8274 |pmc=20966|bibcode = 1998PNAS...95.8274K|doi-access=free }}</ref>

A paper published in 2000 by a team led by [[National Institutes of Health|NIH]] scientist [[John Cisar]] further tested these ideas. It stated that what had previously been described as "self-replication" was a form of [[Crystal structure|crystalline]] growth. The only DNA detected in his specimens was identified as coming from the bacteria ''[[Phyllobacterium myrsinacearum]]'', which is a common contaminant in [[Polymerase chain reaction|PCR]] reactions.<ref name=Cisar >{{cite journal |vauthors=Cisar J, Xu D, Thompson J, Swaim W, Hu L, Kopecko D |title=An alternative interpretation of nanobacteria-induced biomineralization |journal=Proc Natl Acad Sci USA |volume=97 |issue=21 |pages=11511–5 |year=2000 |pmid=11027350 |doi=10.1073/pnas.97.21.11511 |pmc=17231 |bibcode=2000PNAS...9711511C|doi-access=free }}</ref>

==2001–present==
In 2004, a [[Mayo Clinic]] team led by Franklin Cockerill, John Lieske, and [[Virginia M. Miller]] reported to have isolated nanobacteria from diseased human [[artery|arteries]] and [[kidney stone]]s. Their results were published in 2004 and 2006 respectively.<ref name=mayo1 >{{cite journal |vauthors=Miller V, Rodgers G, Charlesworth J, Kirkland B, Severson S, Rasmussen T, Yagubyan M, Rodgers J, Cockerill F, Folk R, Rzewuska-Lech E, Kumar V, Farell-Baril G, Lieske J |title=Evidence of nanobacterial-like structures in calcified human arteries and cardiac valves |journal=Am J Physiol Heart Circ Physiol |volume=287 |issue=3 |pages=H1115–24 |year=2004 |pmid=15142839 |doi=10.1152/ajpheart.00075.2004}}</ref><ref name=mayo2 >{{cite journal  |vauthors=Kumar V, Farell G, Yu S, etal |title=Cell biology of pathologic renal calcification: contribution of crystal transcytosis, cell-mediated calcification, and nanoparticles |journal=J. Investig. Med. |volume=54 |issue=7 |pages=412–24 |date=November 2006  |pmid=17169263 |doi=10.2310/6650.2006.06021|s2cid=26068331 }}</ref> Similar findings were obtained in 2005 by László Puskás at the [[University of Szeged]], Hungary. Dr. Puskás identified these particles in cultures obtained from human atherosclerotic aortic walls and blood samples of atherosclerotic patients but the group was unable to detect DNA in these samples.<ref name=puskas >{{cite journal |vauthors=Puskás L, Tiszlavicz L, Rázga Z, Torday L, Krenács T, Papp J |title=Detection of nanobacteria-like particles in human atherosclerotic plaques |journal=Acta Biol Hung |volume=56 |issue=3–4 |pages=233–45 |year=2005 |pmid=16196199 |doi=10.1556/ABiol.56.2005.3-4.7|bibcode=2005AcBH...56..233P |url=https://publicatio.bibl.u-szeged.hu/28633/1/Detectionofnanobacteria-likeparticlesinhumanatheroscleroticplaquesfulltext.pdf }}</ref>

In 2005, Ciftcioglu and her research team at [[NASA]] used a rotating [[cell culture]] flask, which simulates some aspects of low-gravity conditions, to culture nanobacteria suspected of rapidly forming kidney stones in astronauts. In this environment, they were found to multiply five times faster than in normal Earth gravity. The study concluded that nanobacteria potentially have a role in forming kidney stones and may need to be screened for in crews pre-flight.<ref>{{cite journal |vauthors=Ciftçioglu N, Haddad R, Golden D, Morrison D, McKay D |title=A potential cause for kidney stone formation during space flights: enhanced growth of nanobacteria in microgravity |journal=Kidney Int |volume=67 |issue=2 |pages=483–91 |year=2005 |pmid=15673296 |doi=10.1111/j.1523-1755.2005.67105.x|doi-access=free }}</ref>

An article published to the [[PLOS Pathogens|''Public Library of Science Pathogens'']] (PLOS Pathogens) in February 2008 focused on the comprehensive characterization of nanobacteria. The authors claim that their results rule out the existence of nanobacteria as [[Life|living]] entities and that they are instead a unique [[Self-replication|self-propagating]] entity, namely self-propagating mineral-[[fetuin]] complexes.<ref>{{cite journal  |vauthors=Raoult D, Drancourt M, Azza S, etal |title=Nanobacteria Are Mineralo Fetuin Complexes |journal=PLOS Pathog. |volume=4 |issue=2 |pages=e41 |date=February 2008 |pmid=18282102 |pmc=2242841 |doi=10.1371/journal.ppat.0040041 |doi-access=free }}</ref>

An article published to the [[PNAS|''Proceedings of the National Academy of Sciences'']] (PNAS) in April 2008 also reported that blood nanobacteria are not living organisms, and stated that "CaCO<sub>3</sub> precipitates prepared ''in vitro'' are remarkably similar to purported nanobacteria in terms of their uniformly sized, membrane-delineated vesicular shapes, with cellular division-like formations and aggregations in the form of colonies."<ref name="Martel J, Young JD 2008 5549–54"/> The growth of such "biomorphic" inorganic precipitates was studied in detail in a 2009 ''[[Science (journal)|Science]]'' paper, which showed that unusual [[crystal growth]] mechanisms can produce [[witherite]] precipitates from [[barium chloride]] and [[silica]] solutions that closely resemble primitive organisms.<ref>{{cite journal |vauthors=García-Ruiz JM, Melero-García E, Hyde ST |title=Morphogenesis of self-assembled nanocrystalline materials of barium carbonate and silica |journal=Science |volume=323 |issue=5912 |pages=362–5 |date=January 2009 |pmid=19150841 |doi=10.1126/science.1165349 |url=http://garciaruiz.com/biomorphs/Science_2009_files/Morphogenesis%20of%20Self-Assembled%20Nanocrystalline_JM_science_2009_1.pdf |bibcode=2009Sci...323..362G |s2cid=11977001 |access-date=2009-12-03 |archive-url=https://web.archive.org/web/20120301114608/http://garciaruiz.com/biomorphs/Science_2009_files/Morphogenesis%20of%20Self-Assembled%20Nanocrystalline_JM_science_2009_1.pdf |archive-date=2012-03-01 |url-status=dead }}</ref> The authors commented on the close resemblance of these crystals to putative nanobacteria, stating that their results showed that evidence for life cannot rest on [[Morphology (biology)|morphology]] alone.

Further work on the importance of nanobacteria in geology by R. L. Folk and colleagues includes study of [[calcium carbonate]] [[Bahama]] [[ooids]],<ref>Folk, RL and Lynch. FL (2001) Organic matter, putative nanobacteria and the formation of oolites and hard grounds, Sedimentology, 48:215–229.</ref> [[Silicate mineral|silicate]] [[clay minerals]],<ref>Folk, RL and Lynch, FL, (1997) The possible role of nanobacteria (dwarf bacteria) in clay-mineral diagenesis, Journal of Sedimentary Research, 67:583–589.</ref> [[Sulfide minerals|metal sulfides]],<ref>Folk, RL (2005) nanobacteria and the formation of framboidal pyrite, Journal Earth System Science, 114:369–374</ref> and [[iron oxides]].<ref>Folk, RL and Carlin J (2006) Adventures in an iron birdbath: nanostructure of iron oxide and the nanobacteria connection, Geological Society of America, Abstracts with programs, v. 38 (3), p. 6.</ref> In all of these chemically diverse minerals, the putative nanobacteria are approximately the same size, mainly 0.05–0.2&nbsp;μm. This suggests a [[Common descent|commonality of origin]].{{cn|date=August 2024}} At least for the type locality at Viterbo, Italy, the [[biogenicity]] of these minute cells has been supported by [[transmission electron microscopy]] (TEM).<ref>Kirkland, B and Lynch, FL (2005) nanobacteria, Big Foot and the Loch Ness Monster—what are you supposed to believe?, Geological Society of America, abs. with progr., v. 37:253.</ref> Slices through a green bioslime showed entities 0.09–0.4&nbsp;μm in diameter with definite cell walls and interior dots resembling [[ribosomes]], and even smaller objects with cell walls and [[wikt:lucent|lucent]] interiors with diameters of 0.05&nbsp;μm.<ref>Folk, RL and Kirkland, B, (2007) On the smallness of life: new TEM evidence from biofilm in hot springs, Viterbo, Italy, Geological Society of America, abs. with proper., v. 39 (6) 421.</ref> [[Microbiological culture|Culturable]] organisms on earth are the same 0.05&nbsp;μm size as the supposed nanobacteria on Mars.<ref>Folk, RL and Taylor, L (2002) nanobacterial alteration of pyroxenes in Martian meteorite ALH84001, Meteorology and Planetary Science, v. 37:1057–1070.</ref>

==See also==
* [[Protocell]]
* [[Mycoplasma]] — smallest known bacteria (300&nbsp;nm)
* [[Nanoarchaeum]] — smallest known archaeum (400&nbsp;nm)
* [[Nanobe]] — possible smallest lifeforms (20&nbsp;nm)
* [[Parvovirus]] — smallest known viruses (18–28&nbsp;nm)
* [[Prion]] — smallest known infectious agent (≈10&nbsp;nm)
* [[Ultramicrobacteria]] — possible dormant forms of larger cells (200&nbsp;nm)

==References==
{{reflist|30em}}

==External links==
*[https://doi.org/10.1371/journal.ppat.0030055 Nanobacteria: Facts or Fancies?]
*[https://www.nytimes.com/2006/12/23/science/23microbe.html?hp&ex=1166936400&en=ddbd033a6a93021d&ei=5094&partner=homepage From Scum, Perhaps the Tiniest Form of Life, NY Times December 23, 2006]
*[https://www.wired.com/news/technology/0,1282,66861,00.html Are Nanobacteria Making Us Ill?], Wired News, Mar. 14, 2005
*[https://news.bbc.co.uk/2/hi/science/nature/3729487.stm Claim made for new form of life], BBC News, May 19, 2004
*[https://web.archive.org/web/20080205020037/http://www.medilexicon.com/medicalnews.php?newsid=20076 Infectious Microorganism Linked to Kidney Stones and other Diseases], February 2005
*[https://web.archive.org/web/20060107205619/http://www.msstate.edu/dept/geosciences/4site/nannobacteria.htm Nannobacteria Research Page of the Department of Geosciences, Mississippi State University]
*[https://www.newscientist.com/news/news.jsp?id=ns99995009 New Scientist article about nanobacteria]
*[https://web.archive.org/web/20190921135527/http://www.calcify.com/ The Calcium Bomb — The Nanobacteria Link to Heart Disease and Cancer]
*{{cite book |last=Taylor |first=Michael |title=Dark Life |year=1999 |publisher=Scribner |location=New York, NY |isbn=0-684-84191-6 }}
*[https://www.amazon.com/Time-Travelers-Academy-Reginald-Williams/dp/1847289266/ The Time Travelers Academy], a science fiction novel; it tells a story about the nanobacteria found in Martian meteorites.
*[http://www.jsg.utexas.edu/researcher/robert_folk/] Selected publications of Robert L. Folk on nanobacteria
*{{Cite news|url = http://www.kurzweilai.net/irst-detailed-microscopy-evidence-of-nanobacteria-at-the-lower-size-limit-of-life|title = First detailed microscopy evidence of 'nanobacteria' at the lower size limit of life|date = March 9, 2015|work = Kurzweil AI|access-date =10 March 2015}}

{{Self-replicating organic structures}}
{{Organisms et al.}}

{{Taxonbar|from=Q941131}}

[[Category:Bacterial diseases]]
[[Category:Geomicrobiology]]
[[Category:Unsolved problems in biology]]
[[Category:Hypothetical life forms]]