Algae And Protists Codexery

Anabaena

Filamentous cyanobacteria fixing nitrogen and producing neurotoxins.

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Anabaena is a genus of filamentous cyanobacteria that can differentiate specialized cells called heterocysts for nitrogen fixation under nitrogen-limiting conditions.[1] Anabaena is also used as a model organism to study primitive vision pigments through its sensory rhodopsin protein.[2] The Anabaena genus and Aphanizomenon share considerable taxonomic overlap, and within the ADA clade (which includes Anabaena, Dolichospermum, and Aphanizomenon), numerous sequenced morphospecies fail to form a monophyletic group.[3][4]

Scientific classification

  1. DomainBacteria
  2. KingdomBacillati
  3. PhylumCyanobacteriota
  4. ClassCyanophyceae
  5. OrderNostocales
  6. FamilyNostocaceae
  7. GenusAnabaena

Named by Bory de Saint-Vincent ex Bornet & Flahault, 1886

Sources: Wikipedia taxobox: Anabaena (CC BY-SA 4.0)

Quick Facts

Field
Cyanobacteria
Known for
  • Nitrogen fixation
  • neurotoxin production
  • symbiotic relationships with plants
Neurotoxin producers
One of four genera of cyanobacteria that produce neurotoxins

Facts from the source article.

Key facts and history

Heterocyst cells are terminally specialized for nitrogen fixation, with a micro-oxic interior created by increased respiration and inactivation of photosystem II.[1] Nitrogenase within heterocysts transforms dinitrogen into ammonia using ATP and reductant from carbohydrate metabolism.[1] Carbohydrate synthesized in vegetative cells moves into heterocysts, while fixed nitrogen moves back into vegetative cells as amino acids.[1] Double-strand breaks in DNA are repaired in Anabaena by homologous recombination, with the RecN protein catalyzing an early step.[5]

From 1999 through 2005, the United States Department of Energy conducted a DNA sequencing initiative that produced a full genome map for the model organism Anabaena variabilis ATCC 29413, a genome comprising 7.2 million base pairs.[6] A 2014 publication described the genome sequencing work, with particular attention to heterocysts—cells that transform nitrogen into ammonia.[6] When nitrogen levels are low, vegetative cells along the filaments transform into heterocysts at roughly regular intervals.[1] This partnership is distinctive because the microbe passes directly from one plant generation to the next, resulting in Anabaena azollae being entirely reliant upon its host.[7]

A light-sensitive membrane protein called Anabaena sensory rhodopsin plays a key role in investigations into how light alters molecular shape, thereby triggering the cellular processes and signals underlying vertebrate vision.[2]

References

  1. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: "The Cyanobacteria: Molecular Biology, Genomics and Evolution", Caister Academic Press, January 2014 (we also read that source) en.wikipedia.org
  2. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: Schapiro, "Ultrafast photochemistry of Anabaena Sensory Rhodopsin: Experiment and theory", Biochimica et Biophysica Acta (BBA) - Bioenergetics, May 2014, p. 589–597 (original not read by us) en.wikipedia.org
  3. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: Rajaniemi, "Phylogenetic and morphological evaluation of the genera Anabaena, Aphanizomenon, Trichormus and Nostoc (Nostocales, Cyanobacteria)", International Journal of Systematic and Evolutionary Microbiology, 1 Januar (original not read by us) en.wikipedia.org
  4. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: Dreher, "Complete genomes derived by directly sequencing freshwater bloom populations emphasize the significance of the genus level ADA clade within the Nostocales", Harmful Algae, March 2021 (original not read by us) en.wikipedia.org
  5. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: "InterPro", www.ebi.ac.uk; "Dynamics and Cell-Type Specificity of the DNA Double-Strand Break Repair Protein RecN in the Developmental Cyanobacterium Anabaena sp. Strain PCC 7120", PLoS One, 2015 (original not read by us) en.wikipedia.org
  6. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: "Home - Anabaena variabilis ATCC 29413", genome.jgi.doe.gov; "Anabaena variabilis ATCC 29413, complete genome", 28 January 2014; Thiel, "Complete genome sequence of Anabaena variabilis ATCC 29413.", Standards in Genomic Sciences, 15 June 2014, p. 562–73 (original not read by us) en.wikipedia.org
  7. Wikipedia, "Anabaena" (CC BY-SA 4.0), which cites: The Arctic Azolla event - The Geological Society (original not read by us) en.wikipedia.org

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Anabaena (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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