Cyanobacteria

"Cyanobacterium" redirects here. For the genus, see Cyanobacterium (genus).
"Blue-green algae" and "Green-blue algae" redirect here. For the plant algae, see Green algae.

Cyanobacteria
Temporal range: 2100–0 Ma (Possible Paleoarchean records)
Microscope image of Cylindrospermum, a filamentous genus of cyanobacteria
Scientific classification Edit this classification
Domain: Bacteria
Clade: Terrabacteria
Clade: Cyanobacteria-Melainabacteria group
Phylum: Cyanobacteria
Stanier, 1973
Class: Cyanophyceae
Orders[3]

As of 2014 the taxonomy was under revision[1][2]

Synonyms
List
  • Chloroxybacteria Margulis & Schwartz 1982
  • "Cyanophycota" Parker, Schanen & Renner 1969
  • "Cyanophyta" Steinecke 1931
  • "Diploschizophyta" Dillon 1963
  • "Endoschizophyta" Dillon 1963
  • "Exoschizophyta" Dillon 1963
  • Gonidiophyta Schaffner 1909
  • "Phycobacteria" Cavalier-Smith 1998
  • Phycochromaceae Rabenhorst 1865
  • Prochlorobacteria Jeffrey 1982
  • Prochlorophycota Shameel 2008
  • Prochlorophyta Lewin 1976
  • Chroococcophyceae Starmach 1966
  • Chamaesiphonophyceae Starmach 1966
  • "Cyanobacteriia"
  • Cyanophyceae Sachs 1874
  • Cyanophyta Steinecke 1931
  • Hormogoniophyceae Starmach 1966
  • Myxophyceae Wallroth 1833
  • Nostocophyceae Christensen 1978
  • Pleurocapsophyceae Starmach 1966
  • Prochlorophyceae Lewin 1977
  • Scandophyceae Vologdin 1962
  • Phycochromaceae Rabenhorst 1865
  • Oxyphotobacteria Gibbons & Murray 1978
  • Schizophyceae Cohn 1879

Cyanobacteria (/saɪˌænoʊbækˈtɪəri.ə/), also called Cyanobacteriota or Cyanophyta, are a phylum of autotrophic gram-negative bacteria[4] that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" (from Ancient Greek κύανος (kúanos) 'blue') refers to their bluish green (cyan) color,[5][6] which forms the basis of cyanobacteria's informal common name, blue-green algae,[7][8][9] although as prokaryotes they are not scientifically classified as algae.[note 1]

Cyanobacteria are probably the most numerous taxon to have ever existed on Earth and the first organisms known to have produced oxygen,[10] having appeared in the middle Archean eon and apparently originated in a freshwater or terrestrial environment.[11] Their photopigments can absorb the red- and blue-spectrum frequencies of sunlight (thus reflecting a greenish color) to split water molecules into hydrogen ions and oxygen. The hydrogen ions are used to react with carbon dioxide to produce complex organic compounds such as carbohydrates (a process known as carbon fixation), and the oxygen is released as a byproduct. By continuously producing and releasing oxygen over billions of years, cyanobacteria are thought to have converted the early Earth's anoxic, weakly reducing prebiotic atmosphere, into an oxidizing one with free gaseous oxygen (which previously would have been immediately removed by various surface reductants), resulting in the Great Oxidation Event and the "rusting of the Earth" during the early Proterozoic,[12] dramatically changing the composition of life forms on Earth.[13] The subsequent adaptation of early single-celled organisms to survive in oxygenous environments likely had led to endosymbiosis between anaerobes and aerobes, and hence the evolution of eukaryotes during the Paleoproterozoic.

Cyanobacteria use photosynthetic pigments such as various forms of chlorophyll, carotenoids, phycobilins to convert the photonic energy in sunlight to chemical energy. Unlike heterotrophic prokaryotes, cyanobacteria have internal membranes. These are flattened sacs called thylakoids where photosynthesis is performed.[14][15] Photoautotrophic eukaryotes such as red algae, green algae and plants perform photosynthesis in chlorophyllic organelles that are thought to have their ancestry in cyanobacteria, acquired long ago via endosymbiosis. These endosymbiont cyanobacteria in eukaryotes then evolved and differentiated into specialized organelles such as chloroplasts, chromoplasts, etioplasts, and leucoplasts, collectively known as plastids.

Sericytochromatia, the proposed name of the paraphyletic and most basal group, is the ancestor of both the non-photosynthetic group Melainabacteria and the photosynthetic cyanobacteria, also called Oxyphotobacteria.[16]

The cyanobacteria Synechocystis and Cyanothece are important model organisms with potential applications in biotechnology for bioethanol production, food colorings, as a source of human and animal food, dietary supplements and raw materials.[17] Cyanobacteria produce a range of toxins known as cyanotoxins that can cause harmful health effects in humans and animals.

  1. ^ Silva PC, Moe RL (December 2019). "Cyanophyceae". AccessScience. McGraw Hill Education. doi:10.1036/1097-8542.175300. Retrieved 21 April 2011.
  2. ^ Oren A (September 2004). "A proposal for further integration of the cyanobacteria under the Bacteriological Code". International Journal of Systematic and Evolutionary Microbiology. 54 (Pt 5): 1895–1902. doi:10.1099/ijs.0.03008-0. PMID 15388760.
  3. ^ Komárek J, Kaštovský J, Mareš J, Johansen JR (2014). "Taxonomic classification of cyanoprokaryotes (cyanobacterial genera) 2014, using a polyphasic approach" (PDF). Preslia. 86: 295–335.
  4. ^ Sinha RP, Häder DP (2008). "UV-protectants in cyanobacteria". Plant Science. 174 (3): 278–289. Bibcode:2008PlnSc.174..278S. doi:10.1016/j.plantsci.2007.12.004.
  5. ^ Harper, Douglas. "cyan". Online Etymology Dictionary. Retrieved 21 January 2018.
  6. ^ κύανος. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
  7. ^ "Life History and Ecology of Cyanobacteria". University of California Museum of Paleontology. Archived from the original on 19 September 2012. Retrieved 17 July 2012.
  8. ^ "Taxonomy Browser – Cyanobacteria". National Center for Biotechnology Information. NCBI:txid1117. Retrieved 12 April 2018.
  9. ^ Allaby M, ed. (1992). "Algae". The Concise Dictionary of Botany. Oxford: Oxford University Press.
  10. ^ Crockford PW, Bar On YM, Ward LM, Milo R, Halevy I (November 2023). "The geologic history of primary productivity". Current Biology. 33 (21): 4741–4750.e5. Bibcode:2023CBio...33E4741C. doi:10.1016/j.cub.2023.09.040. PMID 37827153. S2CID 263839383.
  11. ^ Stal LJ, Cretoiu MS (2016). The Marine Microbiome: An Untapped Source of Biodiversity and Biotechnological Potential. Springer Science+Business Media. ISBN 978-3319330006.
  12. ^ Whitton BA, ed. (2012). "The fossil record of cyanobacteria". Ecology of Cyanobacteria II: Their Diversity in Space and Time. Springer Science+Business Media. p. 17. ISBN 978-94-007-3855-3.
  13. ^ "Bacteria". Basic Biology. 18 March 2016.
  14. ^ Liberton M, Pakrasi HB (2008). "Chapter 10. Membrane Systems in Cyanobacteria". In Herrero A, Flore E (eds.). The Cyanobacteria: Molecular Biology, Genomics, and Evolution. Norwich, United Kingdom: Horizon Scientific Press. pp. 217–287. ISBN 978-1-904455-15-8.
  15. ^ Liberton M, Page LE, O'Dell WB, O'Neill H, Mamontov E, Urban VS, Pakrasi HB (February 2013). "Organization and flexibility of cyanobacterial thylakoid membranes examined by neutron scattering". The Journal of Biological Chemistry. 288 (5): 3632–3640. doi:10.1074/jbc.M112.416933. PMC 3561581. PMID 23255600.
  16. ^ Monchamp ME, Spaak P, Pomati F (27 July 2019). "Long Term Diversity and Distribution of Non-photosynthetic Cyanobacteria in Peri-Alpine Lakes". Frontiers in Microbiology. 9: 3344. doi:10.3389/fmicb.2018.03344. PMC 6340189. PMID 30692982.
  17. ^ Pathak J, Rajneesh, Maurya PK, Singh SP, Haeder DP, Sinha RP (2018). "Cyanobacterial Farming for Environment Friendly Sustainable Agriculture Practices: Innovations and Perspectives". Frontiers in Environmental Science. 6. doi:10.3389/fenvs.2018.00007. ISSN 2296-665X.


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