{{Short description|Genus of bacteria}} {{Italic title}} {{Automatic taxobox | taxon = Meiothermus | authority = Nobre ''et al''. 1996 emend. Albuquerque ''et al''. 2009 | type_species = ''Meiothermus ruber'' | type_species_authority = (Loginova et al. 1984) Nobre et al. 1996 | subdivision_ranks = Species | subdivision = *''M. cateniformans'' *''M. cerbereus'' *''M. granaticius'' *''M. hypogaeus'' *''M. luteus'' *"''M. rosaceus''" *''M. ruber'' *''M. rufus'' *''M. taiwanensis'' }} thumb|Thermophiles at Grand Prismatic Spring
'''''Meiothermus''''' is a genus of ''Deinococcota'' bacteria.<ref name=LPSN/><ref name=NCBI/> Members of ''Meiothermus'' can be reliably distinguished from other genera in the family ''Thermaceae'' as well as all other bacteria by the presence of three conserved signature indels (CSIs) found in the proteins: 5-methyltetrahydrofolate–homocysteine methyltransferase, cadmium transporter and polynucleotide phosphorylase and are exclusively shared by species of this genus.<ref>{{Cite journal|last1=Ho|first1=Jonathan|last2=Adeolu|first2=Mobolaji|last3=Khadka|first3=Bijendra|last4=Gupta|first4=Radhey S.|date=October 2016|title=Identification of distinctive molecular traits that are characteristic of the phylum "Deinococcus-Thermus" and distinguish its main constituent groups|url=http://dx.doi.org/10.1016/j.syapm.2016.07.003|journal=Systematic and Applied Microbiology|volume=39|issue=7|pages=453–463|doi=10.1016/j.syapm.2016.07.003|pmid=27506333 |bibcode=2016SyApM..39..453H |issn=0723-2020|url-access=subscription}}</ref> ''Meiothermus'' is also different than the ''Thermus'' genus, which it was originally a member of, in their optimum growth temperatures, with ''Meiothermus'' being able to grow in colder environments. ''Meiothermus'' was first isolated with ''Thermus'' in alkaline and neutral hot springs in Kamchatka, Russia and Yellowstone National Park, USA.
== Characteristics == ''Meiothermus'' species of bacteria are gram-negative and are primarily chemoorganoheterotrophs, and some species can use nitrate as an electron acceptor.<ref name=":3">{{Citation |last1=da Costa |first1=Milton S |title=6 Analysis of Lipids from Extremophilic Bacteria |date=2006-01-01 |url=https://www.sciencedirect.com/science/article/pii/S0580951708700096 |volume=35 |pages=127–159 |publisher=Academic Press |language=en |access-date=2022-11-10 |last2=Nobre |first2=M Fernanda |last3=Wait |first3=Robin|series=Methods in Microbiology |doi=10.1016/S0580-9517(08)70009-6 |isbn=9780125215374 |url-access=subscription }}</ref> The ''Meiothermus'' genus was originally proposed to group together several moderately thermophilic organisms that were in the ''Thermus'' genus. It was later differentiated and made its own genus. ''Meiothermus'' are mostly distinguishable from ''Thermus'' by the lower bound of their optimum growth temperatures, 50-60 °C for ''Meiothermus'' and 70 °C for ''Thermus.'' Also, in ''Meiothermus,'' the presence of two glycolipid bands is seen whereas ''Thermus'' species only contain one.<ref name=":0">{{Cite journal |last1=Ferreira |first1=Ana Margarida |last2=Wait |first2=Robin |last3=Nobre |first3=M. Fernanda |last4=Costa |first4=Milton S. daYR 1999 |title=Characterization of glycolipids from Meiothermus spp. |journal=Microbiology |year=1999 |volume=145 |issue=5 |pages=1191–1199 |doi=10.1099/13500872-145-5-1191 |pmid=10376835 |issn=1465-2080|doi-access=free }}</ref> ''Thermus'' also contains eight conserved signature indels (CSIs) compared to the three that ''Meiothermus'' has. The optimal pH range for ''Meiothermus'' growth is in the range of 7.5–9.5.<ref name=":1">{{Cite journal |last1=Matsui |first1=Tatsunobu |last2=Yamada |first2=Yukie |last3=Mitsuya |first3=Hideki |last4=Shigeri |first4=Yasushi |last5=Yoshida |first5=Yasukazu |last6=Saito |first6=Yoshiro |last7=Matsui |first7=Hiroshi |last8=Watanabe |first8=Kunihiko |date=2009-04-01 |title=Sustainable and practical degradation of intact chicken feathers by cultivating a newly isolated thermophilic Meiothermus ruber H328 |url=https://doi.org/10.1007/s00253-009-1880-4 |journal=Applied Microbiology and Biotechnology |language=en |volume=82 |issue=5 |pages=941–950 |doi=10.1007/s00253-009-1880-4 |pmid=19194700 |s2cid=25880408 |issn=1432-0614|url-access=subscription }}</ref> ''Meiothermus'' is a genus of bacteria that can only exist in aerobic environments. Most ''Meiothermus'' species have a red pigmentation with the exception of ''M. chilarophilus'' which has a yellow color.<ref name=":2">{{Cite journal |last=Bergey |first=D. H. |title=Thermophilic Bacteria |date=July 1919 |journal=Journal of Bacteriology |language=en |volume=4 |issue=4 |pages=301–306 |doi=10.1128/jb.4.4.301-306.1919 |issn=0021-9193 |pmc=378811 |pmid=16558843}}</ref> Some ''Meiothermus'' species can also form biofilms and stick to surfaces using specific adhesion organelles.<ref>{{Cite journal |last1=Raulio |first1=Mari |last2=Järn |first2=Mikael |last3=Ahola |first3=Juhana |last4=Peltonen |first4=Jouko |last5=Rosenholm |first5=Jarl B. |last6=Tervakangas |first6=Sanna |last7=Kolehmainen |first7=Jukka |last8=Ruokolainen |first8=Timo |last9=Narko |first9=Pekka |last10=Salkinoja-Salonen |first10=Mirja |date=July 2008 |title=Microbe repelling coated stainless steel analysed by field emission scanning electron microscopy and physicochemical methods |journal=Journal of Industrial Microbiology & Biotechnology |volume=35 |issue=7 |pages=751–760 |doi=10.1007/s10295-008-0343-8 |issn=1367-5435 |pmid=18379832|s2cid=19876087 |doi-access=free }}</ref>
== Habitats == ''Meiothermus'' is a thermophilic genus of bacteria. Thermophiles are strains of bacteria that exist in environments that range from {{val|45|ul=°C}} to around {{val|80|ul=°C}}.<ref name=":2" /> ''Meiothermus'' in particular is best suited to ranges of {{val|50|–|60|ul=°C}}.<ref name=":0" /> ''Meiothermus'' is a strictly aerobic bacteria, needing oxygen for many of its processes.<ref>Mark D. Spanevello, Bharat K.C. Patel, The phylogenetic diversity of ''Thermus'' and ''Meiothermus'' from microbial mats of an Australian subsurface aquifer runoff channel, ''FEMS Microbiology Ecology'', Volume 50, Issue 1, October 2004, Pages 63–73, {{doi|10.1016/j.femsec.2004.05.008}}</ref>
They also live inside the gut of some Antarctic polychaete worms (Leitoscoloplos geminus, Aphelochaeta palmeri, and Aglaophamus trissophyllus), where they make up a significant part of the worms' microbiome and produce antifreeze proteins that prevents ice formation within their cells and tissues.<ref>[https://www.science.org/doi/10.1126/sciadv.adk9117 Resistance to freezing conditions of endemic Antarctic polychaetes is enhanced by cryoprotective proteins produced by their microbiome]</ref>
== Metabolism == Some species of ''Meiothermus'' have the ability to break down keratin at much a rate much higher than natural rates. These keratinolytic processes performed by ''Meiothermus'' species like the common ''M. ruber'' lead to production of amino acids that can be used by the environment.<ref name=":1" /> ''Meiothermus'' can use other organic substrates like starch, disaccharides, amino acids and others as a carbon and energy source.<ref name=":3" />
==Phylogeny== {{See also|Bacterial taxonomy}} The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)<ref name=LPSN>{{lpsn3|genus/meiothermus|Meiothermus}}</ref> and National Center for Biotechnology Information (NCBI).<ref name=NCBI>{{cite web |author=Schoch CL |display-authors=et al. |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&mode=tree&id=65551&lvl=3 |title=Meiothermus |accessdate=2025-06-05 |publisher=National Center for Biotechnology Information (NCBI) taxonomy database}}</ref>
Species incertae sedis: * "''Meiothermus rosaceus''" <small>Chen et al. 2002</small>
{| class="wikitable" |- ! colspan=1 | 16S rRNA based LTP_10_2024<ref>{{cite web|title=The LTP |url=https://imedea.uib-csic.es/mmg/ltp/#LTP| access-date=10 December 2024}}</ref><ref>{{cite web|title=LTP_all tree in newick format| url=https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_all_10_2024.ntree |access-date=10 December 2024}}</ref><ref>{{cite web|title=LTP_10_2024 Release Notes| url=https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_10_2024_release_notes.pdf |access-date=10 December 2024}}</ref> ! colspan=1 | 120 marker proteins based GTDB 10-RS226<ref name="about">{{cite web |title=GTDB release 10-RS226 |url=https://gtdb.ecogenomic.org/about#4%7C |website=Genome Taxonomy Database|access-date=1 May 2025}}</ref><ref name="tree_bac">{{cite web |title=bac120_r226.sp_label |url=https://data.gtdb.ecogenomic.org/releases/release226/226.0/auxillary_files/bac120_r226.sp_labels.tree |website=Genome Taxonomy Database|access-date=1 May 2025}}</ref><ref name="taxon_history">{{cite web |title=Taxon History |url=https://gtdb.ecogenomic.org/taxon_history/ |website=Genome Taxonomy Database|access-date=1 May 2025}}</ref> |- | style="vertical-align:top| {{Clade | style=font-size:90%;line-height:80% |label1=''Meiothermus'' |1={{clade |1=''M. luteus'' <small>Habib et al. 2017</small> |2={{clade |1={{clade |1=''M. rufus'' <small>Albuquerque et al. 2010</small> |2={{clade |1=''M. granaticius'' <small>Albuquerque et al. 2010</small> |2=''M. hypogaeus'' <small>Mori et al. 2012</small> }} }} |2={{clade |1={{clade |1=''M. cateniformans'' <small>Zhang et al. 2010</small> |2=''M. taiwanensis'' <small>Chen et al. 2002</small> }} |2={{clade |1=''M. cerbereus'' <small>Chung et al. 1997</small> |2=''M. ruber'' <small>(Loginova et al. 1984) Nobre et al. 1996</small> (type sp.) }} }} }} }} }} | {{clade|style=font-size:90%;line-height:80% |label1=''Meiothermus'' |1={{Clade |1=''M. granaticius'' |2={{clade |1={{clade |1=''M. luteus'' |2=''M. rufus'' }} |2={{clade |1=''M. hypogaeus'' |2={{clade |1=''M. cerbereus'' |2={{clade |1=''M. ruber'' |2=''M. taiwanensis'' [incl. ''M. cateniformans''] }} }} }} }} }} }} |}
==See also== * List of bacteria genera * List of bacterial orders
==References== {{Reflist}}
{{Portal bar|Biology}} {{Bacteria classification}} {{Taxonbar|from=Q16985301}}
Category:Deinococcota Category:Gram-negative bacteria Category:Bacteria genera