Biology:Actinomycetota
| Actinomycetota | |
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| Scanning electron micrograph of Actinomyces israelii. | |
Scientific classification 
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| Domain: | Bacteria |
| Clade: | Terrabacteria |
| Phylum: | Actinomycetota Goodfellow 2021[1] |
| Type genus | |
| Actinomyces Harz 1877 (Approved Lists 1980)
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| Classes[2] | |
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| Synonyms | |
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The Actinomycetota (or Actinobacteria) are a diverse phylum of Gram-positive bacteria with high G+C content.[4] They can be terrestrial or aquatic.[5] They are of great economic importance to humans because agriculture and forests depend on their contributions to soil systems. In soil they help to decompose the organic matter of dead organisms so the molecules can be taken up anew by plants. While this role is also played by fungi, Actinomycetota are much smaller and likely do not occupy the same ecological niche. In this role the colonies often grow extensive mycelia, like a fungus would, and the name of an important order of the phylum, Actinomycetales (the actinomycetes), reflects that they were long believed to be fungi. Some soil actinomycetota (such as Frankia) live symbiotically with the plants whose roots pervade the soil, fixing nitrogen for the plants in exchange for access to some of the plant's saccharides. Other species, such as many members of the genus Mycobacterium, are important pathogens.
Beyond the great interest in Actinomycetota for their soil role, much is yet to be learned about them. Although currently understood primarily as soil bacteria, they might be more abundant in fresh waters.[6] Actinomycetota is one of the dominant bacterial phyla and contains one of the largest of bacterial genera, Streptomyces.[7] Streptomyces and other actinomycetota are major contributors to biological buffering of soils.[8] They are also the source of many antibiotics.[9][10]
The Actinomycetota genus Bifidobacterium is the most common bacteria in the microbiome of human infants.[11] Although adults have fewer bifidobacteria, intestinal bifidobacteria help maintain the mucosal barrier and reduce lipopolysaccharide in the intestine.[12]
Although some of the largest and most complex bacterial cells belong to the Actinomycetota, the group of marine Actinomarinales has been described as possessing the smallest free-living prokaryotic cells.[13]
Some Siberian or Antarctic Actinomycetota is said to be the oldest living organism on Earth, frozen in permafrost at around half a million years ago.[14][15] The symptoms of life were detected by CO
2 release from permafrost samples 640 kya or younger.[16]
General
Most Actinomycetota of medical or economic significance are in class Actinomycetia, and belong to the order Actinomycetales. While many of these cause disease in humans, Streptomyces is notable as a source of antibiotics.[10]
Of those Actinomycetota not in the Actinomycetales, Gardnerella is one of the most researched. Classification of Gardnerella is controversial, and MeSH catalogues it as both a Gram-positive and Gram-negative organism.[17]
Actinomycetota, especially Streptomyces spp., are recognized as the producers of many bioactive metabolites that are useful to humans in medicine, such as antibacterials,[18] antifungals,[19] antivirals, antithrombotics, immunomodifiers, antitumor drugs, and enzyme inhibitors; and in agriculture, including insecticides, herbicides, fungicides, and growth-promoting substances for plants and animals.[20] Actinomycetota-derived antibiotics that are important in medicine include aminoglycosides, anthracyclines, chloramphenicol, macrolide, tetracyclines, etc.[citation needed]
Actinomycetota have high guanine and cytosine content in their DNA.[21] The G+C content of Actinomycetota can be as high as 70%, though some may have a low G+C content.[22]
Analysis of glutamine synthetase sequence has been suggested for phylogenetic analysis of the Actinomycetota.[23]
Phylogeny
| Whole-genome based phylogeny[24] | 16S rRNA based LTP_12_2021[25][26][27] | GTDB 08-RS214[28][29][30] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Taxonomy
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)[2] and National Center for Biotechnology Information (NCBI).[31]
- Class ?"Syntrophaliphaticia" corrig. Liu et al. 2020
- Class "Aquicultoria" Jiao et al. 2021
- Class "Geothermincolia" Jiao et al. 2021
- Class "Humimicrobiia" Jiao et al. 2021
- Class Acidimicrobiia Norris 2013
- Class Actinomycetia (Stackebrandt et al. 1997) Salam et al. 2020 (Nitriliruptoria Ludwig et al. 2013)
- Subclass Actinobacteridae Stackebrandt, Rainey & Ward-Rainey 1997
- Subclass Nitriliruptoridae Kurahashi et al. 2010
- Class Coriobacteriia König 2013
- Class Rubrobacteria Suzuki 2013
- Class Thermoleophilia Suzuki and Whitman 2013
See also
References
- ↑ "Valid publication of the names of forty-two phyla of prokaryotes". Int J Syst Evol Microbiol 71 (10): 5056. 2021. doi:10.1099/ijsem.0.005056. PMID 34694987.
- ↑ 2.0 2.1 "Actinobacteria". List of Prokaryotic names with Standing in Nomenclature (LPSN). https://lpsn.dsmz.de/phylum/actinobacteria.
- ↑ "Phylum XXVI. Actinobacteria phyl. nov.". Bergey's Manual of Systematic Bacteriology. 5 (2nd ed.). New York, NY: Springer. 2012. pp. 33–34.
- ↑ "Phylogenetic framework and molecular signatures for the main clades of the phylum Actinobacteria". Microbiology and Molecular Biology Reviews 76 (1): 66–112. March 2012. doi:10.1128/MMBR.05011-11. PMID 22390973.
- ↑ "Evidence excluding the root of the tree of life from the actinobacteria". Mol. Biol. Evol. 25 (1): 1–4. January 2008. doi:10.1093/molbev/msm249. PMID 18003601.
- ↑ "Metagenomics of the water column in the pristine upper course of the Amazon river". PLOS ONE 6 (8): e23785. 2011. doi:10.1371/journal.pone.0023785. PMID 21915244. Bibcode: 2011PLoSO...623785G.
- ↑ "Bacteria". Encyclopedia of Earth. Washington DC: National Council for Science and the Environment. 2010. http://www.eoearth.org/article/Bacteria?topic=49480.
- ↑ "Antagonistic activities of local actinomycete isolates against rice fungal pathogens". African Journal of Microbiology Research 3 (11): 737–742. November 2009.
- ↑ Donald, Lavinia; Pipite, Atanas; Subramani, Ramesh; Owen, Jeremy; Keyzers, Robert A.; Taufa, Taitusi (2022). "Streptomyces: Still the Biggest Producer of New Natural Secondary Metabolites, a Current Perspective" (in en). Microbiology Research 13 (3): 418–465. doi:10.3390/microbiolres13030031. ISSN 2036-7481.
- ↑ 10.0 10.1 Procópio, Rudi Emerson de Lima; Silva, Ingrid Reis da; Martins, Mayra Kassawara; Azevedo, João Lúcio de; Araújo, Janete Magali de (2012). "Antibiotics produced by Streptomyces". The Brazilian Journal of Infectious Diseases 16 (5): 466–471. doi:10.1016/j.bjid.2012.08.014. ISSN 1678-4391. PMID 22975171.
- ↑ "Diversity of bifidobacteria within the infant gut microbiota". PLOS ONE 7 (5): e36957. 2012-05-11. doi:10.1371/journal.pone.0036957. PMID 22606315. Bibcode: 2012PLoSO...736957T.
- ↑ "Microbial translocation in chronic liver diseases". International Journal of Microbiology 2012: 694629. 2012. doi:10.1155/2012/694629. PMID 22848224.
- ↑ "Metagenomics uncovers a new group of low GC and ultra-small marine Actinobacteria". Scientific Reports 3: 2471. 2013. doi:10.1038/srep02471. PMID 23959135. Bibcode: 2013NatSR...3E2471G.
- ↑ "The oldest living organisms: ancient survivors with a fragile future". The Guardian. 2 May 2010. http://www.guardian.co.uk/theobserver/2010/may/02/rachel-sussman-oldest-plants.
- ↑ "The oldest living thing in the world". It's Okay to be Smart. https://www.itsokaytobesmart.com/post/91481365622/siberian-actinobacteria-oldest-living-thing.
- ↑ "Ancient bacteria show evidence of DNA repair". Proceedings of the National Academy of Sciences of the United States of America 104 (36): 14401–14405. September 2007. doi:10.1073/pnas.0706787104. PMID 17728401. Bibcode: 2007PNAS..10414401J.
- ↑ Gardnerella at the US National Library of Medicine Medical Subject Headings (MeSH)
- ↑ "Antibacterial agents from actinomycetes - a review". Frontiers in Bioscience 4: 240–53. 2012. doi:10.2741/e373.
- ↑ "Antifungal antibiotics". Applied Microbiology and Biotechnology 58 (1): 46–57. January 2002. doi:10.1007/s002530100822. PMID 11831475.
- ↑ "Biological control of maize seed pathogenic fungi by use of actinomycetes". Biocontrol 48 (2): 233–240. 2003. doi:10.1023/a:1022673226324.
- ↑ "Genomics of Actinobacteria: tracing the evolutionary history of an ancient phylum". Microbiology and Molecular Biology Reviews 71 (3): 495–548. September 2007. doi:10.1128/MMBR.00005-07. PMID 17804669.
- ↑ "Breaking a paradigm: cosmopolitan and abundant freshwater actinobacteria are low GC". Environmental Microbiology Reports 4 (1): 29–35. February 2012. doi:10.1111/j.1758-2229.2011.00274.x. PMID 23757226. Bibcode: 2012EnvMR...4...29G.
- ↑ "Glutamine synthetase sequence evolution in the mycobacteria and their use as molecular markers for Actinomycetota speciation". BMC Evol. Biol. 9: 48. 2009. doi:10.1186/1471-2148-9-48. PMID 19245690.
- ↑ "Genome-Based Taxonomic Classification of the Phylum Actinobacteria". Front. Microbiol. 9: 2007. 2018. doi:10.3389/fmicb.2018.02007. PMID 30186281.
- ↑ "The LTP". https://imedea.uib-csic.es/mmg/ltp/#LTP.
- ↑ "LTP_all tree in newick format". https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/Tree_LTP_all_12_2021.ntree.
- ↑ "LTP_12_2021 Release Notes". https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_12_2021_release_notes.pdf.
- ↑ "GTDB release 08-RS214". https://gtdb.ecogenomic.org/about#4%7C.
- ↑ "bac120_r214.sp_label". https://data.gtdb.ecogenomic.org/releases/release214/214.0/auxillary_files/bac120_r214.sp_labels.tree.
- ↑ "Taxon History". https://gtdb.ecogenomic.org/taxon_history/.
- ↑ "Actinobacteria". National Center for Biotechnology Information (NCBI) taxonomy database. https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=201174&lvl=3&lin=f&keep=1&srchmode=1&unlock.
Further reading
- "Antibiotic discovery from Actinomycetes: Will a renaissance follow the decline and fall?". SIM News 55: 186–196. 2005.
- "Antimicrobials from Actinomycetes: Back to the Future". Microbe 2 (3): 125–131. 2007. http://www.microbemagazine.org/index.php?option=com_content&view=article&id=2221:antimicrobials-from-actinomycetes-back-to-the-future&catid=546&Itemid=731.
- "Studies on the antibacterial activity of the Actinomycetes isolated from the Khumbu Region of Nepal". International Conference on the Great Himalayas: Climate, Health, Ecology, Management and Conservation. Kathmandu. January 12–15, 2004. http://www.aehms.org/pdf/Panday%20F.pdf.
External links
Wikidata ☰ {{{from}}} entry
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