Saccharibacteria

{{Short description|Bacterial lineage}}

{{Taxobox

|image=41396 2020 736 Fig4 HTML.webp

|image_caption=Ca. Nanosynbacter lyticus (aka TM7x, green) and bacterial hosts (red).
Scale bars are 5 μm.

|domain = Bacteria

|unranked_phylum = CPR group

| phylum = Saccharibacteria

| phylum_authority = Albertsen et al. 2013

| classis = "Saccharimonadia"

| classis_authority = corrig. McLean et al. 2020

| ordo = "Saccharimonadales"

| ordo_authority = corrig. McLean et al. 2020

| subdivision_ranks = Families

| subdivision =

• "Nanogingivalaceae"
• "Nanoperiodontomorbaceae"
• "Nanosynbacteraceae"
• "Nanosyncoccaceae"
• "Saccharimonadaceae"

|synonyms=

• Candidate division TM7

}}

Saccharibacteria, formerly known as TM7,{{cite web |author = Sayers|display-authors = etal| url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=95818&lvl=3&lin=f&keep=1&srchmode=1&unlock |title=Saccharibacteria |accessdate=2021-03-20 |publisher=National Center for Biotechnology Information (NCBI) taxonomy database}}

is a major bacterial lineage. It was discovered through 16S rRNA sequencing . {{Cite journal | doi = 10.1128/MMBR.00033-09 | last1 = Pace | first1 = N. R. | title = Mapping the Tree of Life: Progress and Prospects | journal = Microbiology and Molecular Biology Reviews | volume = 73 | issue = 4 | pages = 565–576 | year = 2009 | pmid = 19946133 | pmc = 2786576}}

TM7x from the human oral cavity was cultivated and revealed that TM7x is an extremely small coccus (200-300 nm) and has a distinctive lifestyle not previously observed in human-associated microbes.{{Cite journal|title = Cultivation of a human-associated TM7 phylotype reveals a reduced genome and epibiotic parasitic lifestyle|journal = Proceedings of the National Academy of Sciences|date = 2015-01-06|issn = 0027-8424|pmc = 4291631|pmid = 25535390|pages = 244–249|volume = 112|issue = 1|doi = 10.1073/pnas.1419038112|first1 = Xuesong|last1 = He|first2 = Jeffrey S.|last2 = McLean|first3 = Anna|last3 = Edlund|first4 = Shibu|last4 = Yooseph|first5 = Adam P.|last5 = Hall|first6 = Su-Yang|last6 = Liu|first7 = Pieter C.|last7 = Dorrestein|first8 = Eduardo|last8 = Esquenazi|first9 = Ryan C.|last9 = Hunter|bibcode = 2015PNAS..112..244H|doi-access = free}} It is an obligate epibiont of various hosts, including Actinomyces odontolyticus strain (XH001) yet also has a parasitic phase thereby killing its host. The full genome sequence revealed a highly reduced genome (705kB) {{cite web | url=https://www.ncbi.nlm.nih.gov/bioproject?term=PRJNA241438 | title=Candidatus Saccharibacteria oral taxon TM7x (ID 241438) - BioProject - NCBI}} and a complete lack of amino acid biosynthetic capacity. An axenic culture of TM7 from the oral cavity was reported in 2014 but no sequence or culture was made available.{{cite journal|last1=Soro|first1=V.|title=Axenic Culture of a Candidate Division TM7 Bacterium from the Human Oral Cavity and Biofilm Interactions with Other Oral Bacteria|journal=Applied and Environmental Microbiology|date=2014|volume=80|issue=20|pages=6480–6489|doi=10.1128/AEM.01827-14|pmid=25107981|pmc=4178647|bibcode=2014ApEnM..80.6480S}}

Along with Candidate Phylum TM6,{{Cite journal|title = Candidate phylum TM6 genome recovered from a hospital sink biofilm provides genomic insights into this uncultivated phylum|journal = Proceedings of the National Academy of Sciences|date = 2013-06-25|issn = 0027-8424|pmc = 3696752|pmid = 23754396|pages = E2390–E2399|volume = 110|issue = 26|doi = 10.1073/pnas.1219809110|first1 = Jeffrey S.|last1 = McLean|first2 = Mary-Jane|last2 = Lombardo|first3 = Jonathan H.|last3 = Badger|first4 = Anna|last4 = Edlund|first5 = Mark|last5 = Novotny|first6 = Joyclyn|last6 = Yee-Greenbaum|first7 = Nikolay|last7 = Vyahhi|first8 = Adam P.|last8 = Hall|first9 = Youngik|last9 = Yang|bibcode = 2013PNAS..110E2390M|doi-access = free}} it was named after sequences obtained in 1994 in an environmental study of a soil sample of peat bog in Germany where 262 PCR amplified 16S rDNA fragments were cloned into a plasmid vector, named TM clones for {{lang|de|Torf, Mittlere Schicht}} (lit. peat, middle layer).{{Cite journal | doi = 10.1007/BF01574689| last1 = Rheims | first1 = H. | last2 = Rainey | first2 = F. A. | last3 = Stackebrandt | first3 = E. | title = A molecular approach to search for diversity among bacteria in the environment | journal = Journal of Industrial Microbiology & Biotechnology | volume = 17 | issue = 3–4 | pages = 159–169 | year = 1996| s2cid = 31868442 | doi-access = free }}

It has been found in several environments since such as from activated sludges,{{Cite journal| last1 = Bond| first1 = PL| last2 = Hugenholtz| first2 = P| last3 = Keller| first3 = J| last4 = Blackall| first4 = LL| title = Bacterial community structures of phosphate-removing and non-phosphate-removing activated sludges from sequencing batch reactors| journal = Applied and Environmental Microbiology| volume = 61| issue = 5| pages = 1910–6| year = 1995| doi = 10.1128/AEM.61.5.1910-1916.1995| pmid = 7544094| pmc = 167453| bibcode = 1995ApEnM..61.1910B}}{{Cite journal| last1 = Godon| first1 = JJ| last2 = Zumstein| first2 = E| last3 = Dabert| first3 = P| last4 = Habouzit| first4 = F| last5 = Moletta| first5 = R| title = Molecular microbial diversity of an anaerobic digestor as determined by small-subunit rDNA sequence analysis| journal = Applied and Environmental Microbiology| volume = 63| issue = 7| pages = 2802–13| year = 1997| doi = 10.1128/AEM.63.7.2802-2813.1997| pmid = 9212428| pmc = 168577| bibcode = 1997ApEnM..63.2802G}} water treatment plant sludge{{Cite journal| last1 = Hugenholtz | first1 = P.| last2 = Tyson | first2 = G. W.| last3 = Webb | first3 = R. I.| last4 = Wagner | first4 = A. M.| last5 = Blackall | first5 = L. L.| title = Investigation of Candidate Division TM7, a Recently Recognized Major Lineage of the Domain Bacteria with No Known Pure-Culture Representatives| journal = Applied and Environmental Microbiology| volume = 67| issue = 1| pages = 411–419| year = 2001| pmid = 11133473| pmc = 92593| doi = 10.1128/AEM.67.1.411-419.2001| bibcode = 2001ApEnM..67..411H}} rainforest soil,{{Cite journal| last1 = Borneman| first1 = J| last2 = Triplett| first2 = EW| title = Molecular microbial diversity in soils from eastern Amazonia: evidence for unusual microorganisms and microbial population shifts associated with deforestation| journal = Applied and Environmental Microbiology| volume = 63| issue = 7| pages = 2647–53| year = 1997| doi = 10.1128/AEM.63.7.2647-2653.1997| pmid = 9212415| pmc = 168563| bibcode = 1997ApEnM..63.2647B}} human saliva,{{Cite journal| last1 = Lazarevic | first1 = V.| last2 = Whiteson | first2 = K.| last3 = Hernandez | first3 = D.| last4 = Francois | first4 = P.| last5 = Schrenzel | first5 = J.| title = Study of inter- and intra-individual variations in the salivary microbiota| journal = BMC Genomics| volume = 11| pages = 523| year = 2010| pmid = 20920195| pmc = 2997015| doi = 10.1186/1471-2164-11-523| doi-access = free}}{{Cite journal| last1 = Dewhirst | first1 = F. E.| last2 = Chen | first2 = T.| last3 = Izard | first3 = J.| last4 = Paster | first4 = B. J.| last5 = Tanner | first5 = A. C. R.| last6 = Yu | first6 = W. -H.| last7 = Lakshmanan | first7 = A.| last8 = Wade | first8 = W. G.| title = The Human Oral Microbiome| journal = Journal of Bacteriology| volume = 192| issue = 19| pages = 5002–5017| year = 2010| pmid = 20656903| pmc = 2944498| doi = 10.1128/JB.00542-10}} in association with sponges,{{Cite journal | last1 = Thiel | first1 = V. | last2 = Leininger | first2 = S. | last3 = Schmaljohann | first3 = R. | last4 = Brümmer | first4 = F. | last5 = Imhoff | first5 = J. F. | title = Sponge-specific Bacterial Associations of the Mediterranean Sponge Chondrilla nucula (Demospongiae, Tetractinomorpha) | doi = 10.1007/s00248-006-9177-y | journal = Microbial Ecology | volume = 54 | issue = 1 | pages = 101–111 | year = 2007 | pmid = 17364249 | pmc = | s2cid = 34564973 }} cockroaches,{{Cite journal| last1 = Berlanga| first1 = M| last2 = Paster| first2 = BJ| last3 = Guerrero| first3 = R| title = The taxophysiological paradox: changes in the intestinal microbiota of the xylophagous cockroach Cryptocercus punctulatus depending on the physiological state of the host| journal = International Microbiology| volume = 12| issue = 4| pages = 227–36| year = 2009| pmid = 20112227}} gold mines,{{Cite journal| last1 = Rastogi | first1 = G.| last2 = Stetler | first2 = L. D.| last3 = Peyton | first3 = B. M.| last4 = Sani | first4 = R. K.| title = Molecular analysis of prokaryotic diversity in the deep subsurface of the former Homestake gold mine, South Dakota, USA| journal = The Journal of Microbiology| volume = 47| issue = 4| pages = 371–384| year = 2009| pmid = 19763410| doi = 10.1007/s12275-008-0249-1| s2cid = 7972151| url = https://scholarworks.montana.edu/xmlui/handle/1/13225}} acetate-amended aquifer sediment,{{Cite journal|title = Small genomes and sparse metabolisms of sediment-associated bacteria from four candidate phyla|journal = mBio |date = 2013-01-01|issn = 2150-7511|pmc = 3812714|pmid = 24149512|pages = e00708–00713|volume = 4|issue = 5|doi = 10.1128/mBio.00708-13|first1 = Rose S.|last1 = Kantor|first2 = Kelly C.|last2 = Wrighton|first3 = Kim M.|last3 = Handley|first4 = Itai|last4 = Sharon|first5 = Laura A.|last5 = Hug|first6 = Cindy J.|last6 = Castelle|first7 = Brian C.|last7 = Thomas|first8 = Jillian F.|last8 = Banfield}} and other environments (bar thermophilic), making it an abundant and widespread phylum. Recently, TM7 rDNA and whole-cells were detected in activated sludge with >99.7% identity to a human skin TM7 and 98.6% identity to the human oral TM7a,{{Cite journal | last1 = Dinis | first1 = J. M. | last2 = Barton | first2 = D. E. | last3 = Ghadiri | first3 = J. | last4 = Surendar | first4 = D. | last5 = Reddy | first5 = K. | last6 = Velasquez | first6 = F. | last7 = Chaffee | first7 = C. L. | last8 = Lee | first8 = M. C. W. | last9 = Gavrilova | first9 = H. | last10 = Ozuna | first10 = H. | last11 = Smits | first11 = S. A. | last12 = Ouverney | first12 = C. C. | editor1-last = Yang | editor1-first = Ching-Hong | title = In Search of an Uncultured Human-Associated TM7 Bacterium in the Environment | doi = 10.1371/journal.pone.0021280 | journal = PLOS ONE | volume = 6 | issue = 6 | pages = e21280 | year = 2011 | pmid = 21701585 | pmc =3118805 |bibcode = 2011PLoSO...621280D | doi-access = free}} suggesting metabolically active TM7 isolates in environmental sites may serve as model organisms to investigate the role TM7 species play in human health.