Cyanobacteria //, also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen. The name "cyanobacteria" comes from the color of the bacteria (Greek: κυανός, translit. kyanós, lit. 'blue'). Cyanobacteria, which are prokaryotes, are also called "blue-green algae", though the term "algae" in modern usage is restricted to eukaryotes.
Temporal range: 3500–0Ma
Phototrophic eukaryotes perform photosynthesis by plastids that may have their ancestry in cyanobacteria, acquired long ago via a process called endosymbiosis. These endosymbiotic cyanobacteria in eukaryotes may have evolved or differentiated into specialized organelles such as chloroplasts, etioplasts and leucoplasts.
By producing and releasing oxygen (as a byproduct of photosynthesis), cyanobacteria are thought to have converted the early oxygen-poor, reducing atmosphere into an oxidizing one, causing the Great Oxygenation Event and the "rusting of the Earth", which dramatically changed the composition of the Earth's life forms and led to the near-extinction of anaerobic organisms.
Cyanobacteria are a group of photosynthetic bacteria, some of which are nitrogen-fixing, that live in a wide variety of moist soils and water either freely or in a symbiotic relationship with plants or lichen-forming fungi (as in the lichen genus Peltigera). They range from unicellular to filamentous and include colonial species. Colonies may form filaments, sheets, or even hollow spheres. Some filamentous species can differentiate into several different cell types: vegetative cells – the normal, photosynthetic cells that are formed under favorable growing conditions; akinetes – climate-resistant spores that may form when environmental conditions become harsh; and thick-walled heterocysts – which contain the enzyme nitrogenase, vital for nitrogen fixation in an anaerobic environment due to its sensitivity to oxygen.
Some cyanobacteria can fix atmospheric nitrogen in anaerobic conditions by means of specialized cells called heterocysts. Heterocysts may also form under the appropriate environmental conditions (anoxic) when fixed nitrogen is scarce. Heterocyst-forming species are specialized for nitrogen fixation and are able to fix nitrogen gas into ammonia (NH3), nitrites (NO−
2) or nitrates (NO−
3), which can be absorbed by plants and converted to protein and nucleic acids (atmospheric nitrogen is not bioavailable to plants, except for those having endosymbiotic nitrogen-fixing bacteria, especially the Fabaceae family, among others).
Free-living cyanobacteria are present in the water of rice paddies, and cyanobacteria can be found growing as epiphytes on the surfaces of the green alga, Chara, where they may fix nitrogen. Cyanobacteria such as Anabaena (a symbiont of the aquatic fern Azolla), can provide rice plantations with biofertilizer.
Many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. The cells in a hormogonium are often thinner than in the vegetative state, and the cells on either end of the motile chain may be tapered. To break away from the parent colony, a hormogonium often must tear apart a weaker cell in a filament, called a necridium.
Each individual cell (each single cyanobacterium) typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia of some species can move about by gliding along surfaces. Many of the multicellular filamentous forms of Oscillatoria are capable of a waving motion; the filament oscillates back and forth. In water columns, some cyanobacteria float by forming gas vesicles, as in archaea. These vesicles are not organelles as such. They are not bounded by lipid membranes, but by a protein sheath.
Cyanobacteria can be found in almost every terrestrial and aquatic habitat—oceans, fresh water, damp soil, temporarily moistened rocks in deserts, bare rock and soil, and even Antarctic rocks. They can occur as planktonic cells or form phototrophic biofilms. They are found in almost every endolithic ecosystem. A few are endosymbionts in lichens, plants, various protists, or sponges and provide energy for the host. Some live in the fur of sloths, providing a form of camouflage.
Aquatic cyanobacteria are known for their extensive and highly visible blooms that can form in both freshwater and marine environments. The blooms can have the appearance of blue-green paint or scum. These blooms can be toxic, and frequently lead to the closure of recreational waters when spotted. Marine bacteriophages are significant parasites of unicellular marine cyanobacteria.
Cyanobacteria growth is favoured in ponds and lakes where waters are calm and have less turbulent mixing. Their life cycles are disrupted when the water naturally or artificially mixes from churning currents caused by the flowing water of streams or the churning water of fountains. For this reason blooms of cyanobacteria seldom occur in rivers unless the water is flowing slowly. Growth is also favored at higher temperatures, making increasing water temperature as a result of global warming more problematic. At higher temperatures Microcystis species are able to outcompete diatoms and green algae. This is a concern because of the production of toxins produced by Microcystis.
Based on environmental trends, models and observations suggest cyanobacteria will likely increase their dominance in aquatic environments. This can lead to serious consequences, particularly the contamination of sources of drinking water. Cyanobacteria can interfere with water treatment in various ways, primarily by plugging filters (often large beds of sand and similar media), and by producing cyanotoxins which have the potential to cause serious illness if consumed. Consequences may also lie within fisheries and waste management practices. Anthropogenic eutrophication, rising temperatures, vertical stratification and increased atmospheric carbon dioxide are contributors to cyanobacteria increasing dominance of aquatic ecosystems.
Cyanobacteria have been found to play an important role in terrestrial habitats. It has been widely reported that cyanobacteria soil crusts help to stabilize soil to prevent erosion and retain water. An example of a cyanobacterial species that does so is Microcoleus vaginatus. M. vaginatus stabilizes soil using a polysaccharide sheath that binds to sand particles and absorbs water.
Some of these organisms contribute significantly to global ecology and the oxygen cycle. The tiny marine cyanobacterium Prochlorococcus was discovered in 1986 and accounts for more than half of the photosynthesis of the open ocean. Many cyanobacteria even display the circadian rhythms that were once thought to exist only in eukaryotic cells (see bacterial circadian rhythms).
"Cyanobacteria are arguably the most successful group of microorganisms on earth. They are the most genetically diverse; they occupy a broad range of habitats across all latitudes, widespread in freshwater, marine, and terrestrial ecosystems, and they are found in the most extreme niches such as hot springs, salt works, and hypersaline bays. Photoautotrophic, oxygen-producing cyanobacteria created the conditions in the planet's early atmosphere that directed the evolution of aerobic metabolism and eukaryotic photosynthesis. Cyanobacteria fulfill vital ecological functions in the world's oceans, being important contributors to global carbon and nitrogen budgets." – Stewart and Falconer
Cyanobacteria use the energy of sunlight to drive photosynthesis, a process where the energy of light is used to synthesize organic compounds from carbon dioxide. Because they are aquatic organisms, they typically employ several strategies which are collectively known as a "carbon concentrating mechanism" to aid in the acquisition of inorganic carbon (CO2 or bicarbonate). Among the more specific strategies is the widespread prevalence of the bacterial microcompartments known as carboxysomes. These icosahedral structures are composed of hexameric shell proteins that assemble into cage-like structures that can be several hundreds of nanometers in diameter. It is believed that these structures tether the CO2-fixing enzyme, RuBisCO, to the interior of the shell, as well as the enzyme carbonic anhydrase, using the paradigm of metabolic channeling to enhance the local CO2 concentrations and thus increase the efficiency of the RuBisCO enzyme.
In contrast to purple bacteria and other bacteria performing anoxygenic photosynthesis, thylakoid membranes of cyanobacteria are not continuous with the plasma membrane but are separate compartments. The photosynthetic machinery is embedded in the thylakoid membranes, with phycobilisomes acting as light-harvesting antennae attached to the membrane, giving the green pigmentation observed (with wavelengths from 450 nm to 660 nm) in most cyanobacteria.
While most of the high-energy electrons derived from water are used by the cyanobacterial cells for their own needs, a fraction of these electrons may be donated to the external environment via electrogenic activity.
Respiration in cyanobacteria can occur in the thylakoid membrane alongside photosynthesis, with their photosynthetic electron transport sharing the same compartment as the components of respiratory electron transport. While the goal of photosynthesis is to store energy by building carbohydrates from CO2, respiration is the reverse of this, with carbohydrates turned back into CO2 accompanying energy release.
Cyanobacteria appear to separate these two processes with their plasma membrane containing only components of the respiratory chain, while the thylakoid membrane hosts an interlinked respiratory and photosynthetic electron transport chain. Cyanobacteria use electrons from succinate dehydrogenase rather than from NADPH for respiration.
Electron transport chainEdit
Many cyanobacteria are able to reduce nitrogen and carbon dioxide under aerobic conditions, a fact that may be responsible for their evolutionary and ecological success. The water-oxidizing photosynthesis is accomplished by coupling the activity of photosystem (PS) II and I (Z-scheme). In contrast to green sulfur bacteria which only use one photosystem, the use of water as an electron donor is energetically demanding, requiring two photosystems.
Attached to the thylakoid membrane, phycobilisomes act as light-harvesting antennae for the photosystems. The phycobilisome components (phycobiliproteins) are responsible for the blue-green pigmentation of most cyanobacteria. The variations on this theme are due mainly to carotenoids and phycoerythrins that give the cells their red-brownish coloration. In some cyanobacteria, the color of light influences the composition of the phycobilisomes. In green light, the cells accumulate more phycoerythrin, whereas in red light they produce more phycocyanin. Thus, the bacteria appear green in red light and red in green light. This process of complementary chromatic adaptation is a way for the cells to maximize the use of available light for photosynthesis.
A few genera lack phycobilisomes and have chlorophyll b instead (Prochloron, Prochlorococcus, Prochlorothrix). These were originally grouped together as the prochlorophytes or chloroxybacteria, but appear to have developed in several different lines of cyanobacteria. For this reason, they are now considered as part of the cyanobacterial group.
In general, photosynthesis in cyanobacteria uses water as an electron donor and produces oxygen as a byproduct, though some may also use hydrogen sulfide a process which occurs among other photosynthetic bacteria such as the purple sulfur bacteria.
Carbon dioxide is reduced to form carbohydrates via the Calvin cycle. The large amounts of oxygen in the atmosphere are considered to have been first created by the activities of ancient cyanobacteria. They are often found as symbionts with a number of other groups of organisms such as fungi (lichens), corals, pteridophytes (Azolla), angiosperms (Gunnera), etc.
Relationship to chloroplastsEdit
Primary chloroplasts are cell organelles found in some eukaryotic lineages, where they are specialized in performing the photosynthesis. They are known to have evolved from cyanobacteria through endosymbiosis, i.e. after the engulfment of a cell by another. In this case, a photosynthesizing cyanobacteria that was engulfed in some ancient eukaryotic cell. After some years of debate, it is now generally accepted that the three major groups of primary endosymbiotic eukaryotes (i.e. green plants, red algae and glaucophytes) form one large monophyletic group called Archaeplastida, which evolved after one unique endosymbiotic event.
The morphological similarity between chloroplasts and cyanobacteria was first reported by German botanist Andreas Schimper in the 19th century Chloroplasts are only found in plants and algae, thus paving the way for Russian biologist Konstantin Mereschkowski to suggest the symbiogenic origin of the plastid in 1905. Lynn Margulis brought this hypothesis back to attention more than 60 years later but it was not until supplementary data started to accumulate than the idea became fully accepted. The cyanobacterial origin of plastids is now supported by various pieces of phylogenetic, genomic, biochemical and structural evidence. The fact that another independent and more recent primary endosymbiosis event has been described between a cyanobacterium and a separate eukaryote lineage (the rhizarian Paulinella chromatophora) also gives credibility to the endosymbiotic origin of the plastid.
In addition to this primary endosymbiosis, many eukaryotic lineages have been subject to secondary or even tertiary endosymbiotic events, that is the "Matryoshka-like" engulfment by a eukaryote of another plastid-bearing eukaryote.
Within this evolutionary context, it is noteworthy that, as far as we can tell, oxygenic photosynthesis only evolved once (in cyanobacteria), and all other photosynthetic eukaryotes (including all plants and algae) have acquired this ability from them. In other words, all the oxygen that makes the atmosphere breathable for aerobic organisms originally comes from cyanobacteria or their later descendants.
Historically, bacteria were first classified as plants constituting the class Schizomycetes, which along with the Schizophyceae (blue-green algae/Cyanobacteria) formed the phylum Schizophyta, then in the phylum Monera in the kingdom Protista by Haeckel in 1866, comprising Protogens, Protamaeba, Vampyrella, Protomonae, and Vibrio, but not Nostoc and other cyanobacteria, which were classified with algae, later reclassified as the Prokaryotes by Chatton.
The cyanobacteria were traditionally classified by morphology into five sections, referred to by the numerals I-V. The first three – Chroococcales, Pleurocapsales, and Oscillatoriales – are not supported by phylogenetic studies. The latter two – Nostocales and Stigonematales – are monophyletic, and make up the heterocystous cyanobacteria.
The members of Chroococales are unicellular and usually aggregate in colonies. The classic taxonomic criterion has been the cell morphology and the plane of cell division. In Pleurocapsales, the cells have the ability to form internal spores (baeocytes). The rest of the sections include filamentous species. In Oscillatoriales, the cells are uniseriately arranged and do not form specialized cells (akinetes and heterocysts). In Nostocales and Stigonematales, the cells have the ability to develop heterocysts in certain conditions. Stigonematales, unlike Nostocales, include species with truly branched trichomes.
- The classes Chroobacteria, Hormogoneae, and Gloeobacteria
- The orders Chroococcales, Gloeobacterales, Nostocales, Oscillatoriales, Pleurocapsales, and Stigonematales
- The families Prochloraceae and Prochlorotrichaceae
- The genera Halospirulina, Planktothricoides, Prochlorococcus, Prochloron, and Prochlorothrix
The remainder are validly published under the International Code of Nomenclature for algae, fungi, and plants.
Stromatolites are layered biochemical accretionary structures formed in shallow water by the trapping, binding, and cementation of sedimentary grains by biofilms (microbial mats) of microorganisms, especially cyanobacteria.
During the Precambrian, stromatolite communities of microorganisms grew in most marine and non-marine environments in the photic zone. After the Cambrian explosion of marine animals, grazing on the stromatolite mats by herbivores greatly reduced the occurrence of the stromatolites in marine environments. Since then, they are found mostly in hypersaline conditions where grazing invertebrates cannot live (e.g. Shark Bay, Western Australia). Stromatolites provide ancient records of life on Earth by fossil remains which might date from more than 3.5 Ga ago, but this is disputed. As of 2010[update] the oldest undisputed evidence of cyanobacteria is from 2.1 Ga ago, but there is some evidence for them as far back as 2.7 Ga ago. Oxygen levels in the atmosphere remained around or below 1% of today's level until 2.4 Ga ago (the Great Oxygenation Event). The rise in oxygen may have caused a fall in methane levels, and triggered the Huronian glaciation from around 2.4 to 2.1 Ga ago. In this way, cyanobacteria may have killed off much of the other bacteria of the time.
Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by cyanobacterial growth. Oncolites are similar to stromatolites, but instead of forming columns, they form approximately spherical structures that were not attached to the underlying substrate as they formed. The oncoids often form around a central nucleus, such as a shell fragment, and a calcium carbonate structure is deposited by encrusting microbes. Oncolites are indicators of warm waters in the photic zone, but are also known in contemporary freshwater environments. These structures rarely exceed 10 cm in diameter.
Biotechnology and applicationsEdit
The unicellular cyanobacterium Synechocystis sp. PCC6803 was the third prokaryote and first photosynthetic organism whose genome was completely sequenced. It continues to be an important model organism. Cyanothece ATCC 51142 is an important diazotrophic model organism. The smallest genomes have been found in Prochlorococcus spp. (1.7 Mb) and the largest in Nostoc punctiforme (9 Mb). Those of Calothrix spp. are estimated at 12–15 Mb, as large as yeast.
Recent research has suggested the potential application of cyanobacteria to the generation of renewable energy by converting sunlight into electricity. Internal photosynthetic pathways can be coupled to chemical mediators that transfer electrons to external electrodes. Currently, efforts are underway to commercialize algae-based fuels such as diesel, gasoline, and jet fuel.
Researchers from a company called Algenol have cultured genetically modified cyanobacteria in sea water inside a clear plastic enclosure so they first make sugar (pyruvate) from CO2 and the water via photosynthesis. Then, the bacteria secrete ethanol from the cell into the salt water. As the day progresses, and the solar radiation intensifies, ethanol concentrations build up and the ethanol itself evaporates onto the roof of the enclosure. As the sun recedes, evaporated ethanol and water condense into droplets, which run along the plastic walls and into ethanol collectors, from where it is extracted from the enclosure with the water and ethanol separated outside the enclosure. As of March 2013, Algenol was claiming to have tested its technology in Florida and to have achieved yields of 9,000 US gallons per acre per year. This could potentially meet US demands for ethanol in gasoline in 2025, assuming a B30 blend, from an area of around half the size of California’s San Bernardino County, requiring less than one-tenth of the area than ethanol from other biomass, such as corn, and only very limited amounts of fresh water.
Cyanobacteria may possess the ability to produce substances that could one day serve as anti-inflammatory agents and combat bacterial infections in humans.
Spirulina's extracted blue color is used as a natural food coloring in gum and candy.
Researchers from several space agencies argue that cyanobacteria could be used for producing goods for human consumption in future manned outposts on Mars, by transforming materials available on this planet.
Specific toxins include, anatoxin-a, anatoxin-as, aplysiatoxin, cyanopeptolin, cylindrospermopsin, domoic acid, nodularin R (from Nodularia), neosaxitoxin, and saxitoxin. Cyanobacteria reproduce explosively under certain conditions. This results in algal blooms, which can become harmful to other species, and pose a danger to humans and animals, if the cyanobacteria involved produce toxins. Several cases of human poisoning have been documented, but a lack of knowledge prevents an accurate assessment of the risks.
Recent studies suggest that significant exposure to high levels of cyanobacteria producing toxins such as BMAA can cause amyotrophic lateral sclerosis (ALS). People living within half a mile of cyanobacterially contaminated lakes have had a 2.3-times greater risk of developing ALS than the rest of the population; people around New Hampshire’s Lake Mascoma had an up to 25 times greater risk of ALS than the expected incidence. BMAA from desert crusts found throughout Qatar might have contributed to higher rates of ALS in Gulf War veterans.
Several chemicals can eliminate cyanobacterial blooms from water-based systems. They include: calcium hypochlorite, copper sulphate, cupricide, and simazine. The calcium hypochlorite amount needed varies depending on the cyanobacteria bloom, and treatment is needed periodically. According to the Department of Agriculture Australia, a rate of 12 g of 70% material in 1000 l of water is often effective to treat a bloom. Copper sulfate is also used commonly, but no longer recommended by the Australian Department of Agriculture, as it kills livestock, crustaceans, and fish. Culpricide is a chelated copper product that eliminates blooms with lower toxicity risks than copper sulfate. Dosage recommendations vary from 190 ml to 4.8 l per 1000 m2. Ferric alum treatments at the rate of 50 mg/l will reduce algae blooms. Simazine, which is also a herbicide, will continue to kill blooms for several days after an application. Simazine is marketed at different strengths (25, 50, and 90%), the recommended amount needed for one cubic meter of water per product is 25% product 8 ml; 50% product 4 ml; or 90% product 2.2 ml.
Despite the associated toxins which many of the members of this phylum produce, some microalgae also contain substances of high biological value, such as polyunsaturated fatty acids, amino acids (proteins), pigments, antioxidants, vitamins, and minerals. Edible blue-green algae reduce the production of pro-inflammatory cytokines by inhibiting NF-κB pathway in macrophages and splenocytes. Sulfate polysaccharides exhibit immunomodulatory, antitumor, antithrombotic, anticoagulant, anti-mutagenic, anti-inflammatory, antimicrobial, and even antiviral activity against HIV, herpes, and hepatitis.
- "Cyanophyceae". Cyanophyceae. Access Science. Retrieved 21 April 2011.
- 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): 1895–902. doi:10.1099/ijs.0.03008-0. PMID 15388760.
- 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.
- "Life History and Ecology of Cyanobacteria". University of California Museum of Paleontology. Retrieved 17 July 2012.
- Hamilton TL, Bryant DA, Macalady JL (February 2016). "The role of biology in planetary evolution: cyanobacterial primary production in low-oxygen Proterozoic oceans". Environmental Microbiology. 18 (2): 325–40. doi:10.1111/1462-2920.13118. PMC . PMID 26549614.
- "cyan | Origin and meaning of cyan by Online Etymology Dictionary". www.etymonline.com. Retrieved 2018-01-21.
- "Henry George Liddell, Robert Scott, A Greek-English Lexicon, κύα^νος". www.perseus.tufts.edu. Retrieved 2018-01-21.
- "Taxonomy Browser - Cyanobacteria". National Center for Biotechnology Information. NCBI:txid1117. Retrieved 12 April 2018.
- Allaby, M, ed. (1992). "Algae". The Concise Dictionary of Botany. Oxford: Oxford University Press.
- Liberton M, Pakrasi HB (2008). "Chapter 10. Membrane Systems in Cyanobacteria". In Herrero A, Flore E. The Cyanobacteria: Molecular Biology, Genomics, and Evolution. Norwich, United Kingdom: Horizon Scientific Press. pp. 217–287. ISBN 978-1-904455-15-8.
- 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): 3632–40. doi:10.1074/jbc.M112.416933. PMC . PMID 23255600.
- Whitton BA, ed. (5 July 2012). "The fossil record of cyanobacteria". Ecology of Cyanobacteria II: Their Diversity in Space and Time. Springer Science & Business Media. pp. 17–. ISBN 978-94-007-3855-3.
- Dodds WK, Gudder DA, Mollenhauer D (1995). "T he ecology of Nostoc". Journal of Phycology. 31: 2–18. doi:10.1111/j.0022-3646.1995.00002.x.
- Meeks JC, Elhai J, Thiel T, Potts M, Larimer F, Lamerdin J, Predki P, Atlas R (2001). "An overview of the genome of Nostoc punctiforme, a multicellular, symbiotic cyanobacterium". Photosynthesis Research. 70 (1): 85–106. doi:10.1023/A:1013840025518. PMID 16228364.
- Golden JW, Yoon HS (December 1998). "Heterocyst formation in Anabaena". Current Opinion in Microbiology. 1 (6): 623–9. doi:10.1016/s1369-5274(98)80106-9. PMID 10066546.
- Fay P (June 1992). "Oxygen relations of nitrogen fixation in cyanobacteria". Microbiological Reviews. 56 (2): 340–73. PMC . PMID 1620069.
- Sims GK, Dunigan EP (1984). "Diurnal and seasonal variations in nitrogenase activity (C2H2 reduction) of rice roots". Soil Biology and Biochemistry. 16: 15–18. doi:10.1016/0038-0717(84)90118-4.
- "Azolla-Anabaena as a Biofertilizer for Rice Paddy Fields in the Po Valley, a Temperate Rice Area in Northern Italy". Azolla-Anabaena as a Biofertilizer for Rice Paddy Fields in the Po Valley, a Temperate Rice Area in Northern Italy. International Journal of Agronomy. Retrieved 21 April 2011.
- Risser DD, Chew WG, Meeks JC (April 2014). "Genetic characterization of the hmp locus, a chemotaxis-like gene cluster that regulates hormogonium development and motility in Nostoc punctiforme". Molecular Microbiology. 92 (2): 222–33. doi:10.1111/mmi.12552. PMID 24533832.
- Khayatan B, Bains DK, Cheng MH, Cho YW, Huynh J, Kim R, Omoruyi OH, Pantoja AP, Park JS, Peng JK, Splitt SD, Tian MY, Risser DD (May 2017). "A Putative O-Linked β-N-Acetylglucosamine Transferase Is Essential for Hormogonium Development and Motility in the Filamentous Cyanobacterium Nostoc punctiforme". Journal of Bacteriology. 199 (9): e00075–17. doi:10.1128/JB.00075-17. PMC . PMID 28242721.
- Singh. Text Book Of Botany Diversity Of Microbes And Cryptogams. Rastogi Publications. ISBN 9788171338894.
- "Differences between Bacteria and Cyanobacteria". Microbiology Notes. 2015-10-29. Retrieved 2018-01-21.
- Walsby AE (March 1994). "Gas vesicles". Microbiological Reviews. 58 (1): 94–144. PMC . PMID 8177173.
- de los Ríos A, Grube M, Sancho LG, Ascaso C (February 2007). "Ultrastructural and genetic characteristics of endolithic cyanobacterial biofilms colonizing Antarctic granite rocks". FEMS Microbiology Ecology. 59 (2): 386–95. doi:10.1111/j.1574-6941.2006.00256.x. PMID 17328119.
- Vaughan T (2011). Mammalogy. Jones and Barlett. p. 21. ISBN 9780763762995.
- Schultz, Nora (30 August 2009). "Photosynthetic viruses keep world's oxygen levels up". New Scientist.
- Jöhnk KD, Huisman J, Sharples J, Sommeijer B, Visser PM, Stroom JM (1 March 2008). "Summer heatwaves promote blooms of harmful cyanobacteria". Global Change Biology. 14 (3): 495–512. doi:10.1111/j.1365-2486.2007.01510.x. ISSN 1365-2486.
- Paerl HW, Paul VJ (April 2012). "Climate change: links to global expansion of harmful cyanobacteria". Water Research. 46 (5): 1349–63. doi:10.1016/j.watres.2011.08.002. PMID 21893330.
- Thomas AD, Dougill AJ (15 March 2007). "Spatial and temporal distribution of cyanobacterial soil crusts in the Kalahari: Implications for soil surface properties". Geomorphology. 85 (1): 17–29. doi:10.1016/j.geomorph.2006.03.029.
- Belnap J, Gardner JS (1993). "Soil Microstructure in Soils of the Colorado Plateau: The Role of the Cyanobacterium Microcoleus Vaginatus". The Great Basin Naturalist. 53 (1): 40–47. doi:10.2307/41712756. Retrieved 8 October 2017.
- Nadis S (December 2003). "The cells that rule the seas" (PDF). Scientific American. 289 (6): 52–3. Bibcode:2003SciAm.289f..52N. doi:10.1038/scientificamerican1203-52. PMID 14631732.
- Walsh PJ, Smith S, Fleming L, Solo-Gabriele H, Gerwick WH, eds. (2 September 2011). "Cyanobacteria and cyanobacterial toxins". Oceans and Human Health: Risks and Remedies from the Seas. Academic Press. pp. 271–296. ISBN 978-0-08-087782-2.
- Kerfeld CA, Heinhorst S, Cannon GC (2010). "Bacterial microcompartments". Annual Review of Microbiology. 64 (1): 391–408. doi:10.1146/annurev.micro.112408.134211. PMID 20825353.
- Long BM, Badger MR, Whitney SM, Price GD (October 2007). "Analysis of carboxysomes from Synechococcus PCC7942 reveals multiple Rubisco complexes with carboxysomal proteins CcmM and CcaA". The Journal of Biological Chemistry. 282 (40): 29323–35. doi:10.1074/jbc.M703896200. PMID 17675289.
- Vothknecht UC, Westhoff P (December 2001). "Biogenesis and origin of thylakoid membranes". Biochimica et Biophysica Acta. 1541 (1–2): 91–101. doi:10.1016/S0167-4889(01)00153-7. PMID 11750665.
- Sobiechowska-Sasim M, Stoń-Egiert J, Kosakowska A (February 2014). "Quantitative analysis of extracted phycobilin pigments in cyanobacteria—an assessment of spectrophotometric and spectrofluorometric methods". J Appl Phycol. 26: 2065–2074. doi:10.1007/s10811-014-0244-3. PMC .
- Pisciotta JM, Zou Y, Baskakov IV (May 2010). Yang C, ed. "Light-dependent electrogenic activity of cyanobacteria". PLOS One. 5 (5): e10821. Bibcode:2010PLoSO...510821P. doi:10.1371/journal.pone.0010821. PMC . PMID 20520829.
- Vermaas WF (2001). Photosynthesis and Respiration in Cyanobacteria. eLS. John Wiley & Sons, Ltd. doi:10.1038/npg.els.0001670. ISBN 978-0-470-01590-2.
- Klatt JM, de Beer D, Häusler S, Polerecky L (2016). "Cyanobacteria in Sulfidic Spring Microbial Mats Can Perform Oxygenic and Anoxygenic Photosynthesis Simultaneously during an Entire Diurnal Period". Frontiers in Microbiology. 7: 1973. doi:10.3389/fmicb.2016.01973. PMC . PMID 28018309.
- Grossman AR, Schaefer MR, Chiang GG, Collier JL (September 1993). "The phycobilisome, a light-harvesting complex responsive to environmental conditions" (PDF). Microbiological Reviews. 57 (3): 725–49. PMC . PMID 8246846.
- "Colors from bacteria | Causes of Color". www.webexhibits.org. Retrieved 2018-01-22.
- Garcia-Pichel F. "Cyanobacteria". In Schaechter M. Encyclopedia of Microbiology (third ed.). pp. 107–124. doi:10.1016/B978-012373944-5.00250-9. ISBN 978-0-12-373944-5.
- Kehoe DM (May 2010). "Chromatic adaptation and the evolution of light color sensing in cyanobacteria". Proceedings of the National Academy of Sciences of the United States of America. 107 (20): 902930. doi:10.1073/pnas.1004510107. PMC . PMID 20457899.
- Kehoe DM, Gutu A (2006). "Responding to color: the regulation of complementary chromatic adaptation". Annual Review of Plant Biology. 57: 127–50. doi:10.1146/annurev.arplant.57.032905.105215. PMID 16669758.
- Palenik B, Haselkorn R (January 1992). "Multiple evolutionary origins of prochlorophytes, the chlorophyll b-containing prokaryotes". Nature. 355 (6357): 265–7. doi:10.1038/355265a0. PMID 1731224.
- Urbach E, Robertson DL, Chisholm SW (January 1992). "Multiple evolutionary origins of prochlorophytes within the cyanobacterial radiation". Nature. 355 (6357): 267–70. doi:10.1038/355267a0. PMID 1731225.
- Cohen Y, Jørgensen BB, Revsbech NP, Poplawski R (February 1986). "Adaptation to Hydrogen Sulfide of Oxygenic and Anoxygenic Photosynthesis among Cyanobacteria". Applied and Environmental Microbiology. 51 (2): 398–407. PMC . PMID 16346996.
- Blankenship RE (2014). Molecular Mechanisms of Photosynthesis. Wiley-Blackwell. pp. 147–173. ISBN 978-1-4051-8975-0.
- Och LM, Shields-Zhou GA (January 2012). "The Neoproterozoic oxygenation event: Environmental perturbations and biogeochemical cycling". Earth-Science Reviews. 110 (1–4): 26–57. doi:10.1016/j.earscirev.2011.09.004.
- Adams DG, Bergman B, Nierzwicki-Bauer SA, Duggan PS, Rai AN, Schüßler A (2013). The Prokaryotes. Springer, Berlin, Heidelberg. pp. 359–400. doi:10.1007/978-3-642-30194-0_17. ISBN 978-3-642-30193-3.
- Smith A (1973). "Synthesis of metabolic intermediates". In Carr NG, Whitton BA. The Biology of Blue-green Algae. University of California Press. pp. 30–. ISBN 978-0-520-02344-4.
- Jangoux M (1987). "Diseases of Echinodermata. I. Agents microorganisms and protistans" (PDF). Dis. Aquat. Org. 2: 147–162. doi:10.3354/dao002147.
- Kinne O (ed.). Diseases of Marine Animals (PDF). 1. Chichester, UK: John Wiley & Sons. ISBN 978-0-471-99584-5.
- Kristiansen A (1964). "Sarcinastrum urosporae, a Colourless Parasitic Blue-green Alga" (PDF). Phycologia. 4 (1): 19–22. doi:10.2216/i0031-8884-4-1-19.1. Archived from the original (PDF) on 6 January 2015.
- Keeling PJ (2013). "The number, speed, and impact of plastid endosymbioses in eukaryotic evolution". Annual Review of Plant Biology. 64: 583–607. doi:10.1146/annurev-arplant-050312-120144. PMID 23451781.
- Howe CJ, Barbrook AC, Nisbet RE, Lockhart PJ, Larkum AW (August 2008). "The origin of plastids". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 363 (1504): 2675–85. doi:10.1098/rstb.2008.0050. PMC . PMID 18468982.
- Rodríguez-Ezpeleta N, Brinkmann H, Burey SC, Roure B, Burger G, Löffelhardt W, Bohnert HJ, Philippe H, Lang BF (July 2005). "Monophyly of primary photosynthetic eukaryotes: green plants, red algae, and glaucophytes". Current Biology. 15 (14): 1325–30. doi:10.1016/j.cub.2005.06.040. PMID 16051178.
- Adl SM, Simpson AG, Lane CE, Lukeš J, Bass D, Bowser SS, Brown MW, Burki F, Dunthorn M, Hampl V, Heiss A, Hoppenrath M, Lara E, Le Gall L, Lynn DH, McManus H, Mitchell EA, Mozley-Stanridge SE, Parfrey LW, Pawlowski J, Rueckert S, Shadwick L, Shadwick L, Schoch CL, Smirnov A, Spiegel FW (September 2012). "The revised classification of eukaryotes". The Journal of Eukaryotic Microbiology. 59 (5): 429–93. doi:10.1111/j.1550-7408.2012.00644.x. PMC . PMID 23020233.
- Price DC, Chan CX, Yoon HS, Yang EC, Qiu H, Weber AP, Schwacke R, Gross J, Blouin NA, Lane C, Reyes-Prieto A, Durnford DG, Neilson JA, Lang BF, Burger G, Steiner JM, Löffelhardt W, Meuser JE, Posewitz MC, Ball S, Arias MC, Henrissat B, Coutinho PM, Rensing SA, Symeonidi A, Doddapaneni H, Green BR, Rajah VD, Boore J, Bhattacharya D (February 2012). "Cyanophora paradoxa genome elucidates origin of photosynthesis in algae and plants". Science. 335 (6070): 843–7. doi:10.1126/science.1213561. PMID 22344442.
- Ponce-Toledo RI, Deschamps P, López-García P, Zivanovic Y, Benzerara K, Moreira D (February 2017). "An Early-Branching Freshwater Cyanobacterium at the Origin of Plastids". Current Biology. 27 (3): 386–391. doi:10.1016/j.cub.2016.11.056. PMC . PMID 28132810.
- Schimper, A.F.W. (1883). "Über die Entwicklung der Chlorophyllkörner und Farbkörper" [About the development of the chlorophyll grains and stains]. Bot. Zeitung (in German). 41: 105–14, 121–31, 137–46, 153–62. Archived from the original on 19 October 2013.
- Alberts B (2002). Molecular biology of the cell (4. ed.). New York [u.a.]: Garland. ISBN 0-8153-4072-9.
- Mereschkowsky C (1905). "Über Natur und Ursprung der Chromatophoren im Pflanzenreiche" [About the nature and origin of chromatophores in the vegetable kingdom]. Biol Centralbl (in German). 25: 593–604.
- Sagan L (March 1967). "On the origin of mitosing cells". Journal of Theoretical Biology. 14 (3): 255–74. doi:10.1016/0022-5193(67)90079-3. PMID 11541392.
- Schwartz RM, Dayhoff MO (January 1978). "Origins of prokaryotes, eukaryotes, mitochondria, and chloroplasts". Science. 199 (4327): 395–403. doi:10.1126/science.202030. PMID 202030.
- Archibald JM (August 2015). "Genomic perspectives on the birth and spread of plastids". Proceedings of the National Academy of Sciences of the United States of America. 112 (33): 10147–53. doi:10.1073/pnas.1421374112. PMC . PMID 25902528.
- Blankenship RE (October 2010). "Early evolution of photosynthesis". Plant Physiology. 154 (2): 434–8. doi:10.1104/pp.110.161687. PMC . PMID 20921158.
- Rockwell NC, Lagarias JC, Bhattacharya D (2014). "Primary endosymbiosis and the evolution of light and oxygen sensing in photosynthetic eukaryotes". Frontiers in Ecology and Evolution. 2 (66). doi:10.3389/fevo.2014.00066. PMC . PMID 25729749.
- Summarised in Cavalier-Smith T (April 2000). "Membrane heredity and early chloroplast evolution". Trends in Plant Science. 5 (4): 174–82. doi:10.1016/S1360-1385(00)01598-3. PMID 10740299.
- Nowack EC, Melkonian M, Glöckner G (March 2008). "Chromatophore genome sequence of Paulinella sheds light on acquisition of photosynthesis by eukaryotes". Current Biology. 18 (6): 410–8. doi:10.1016/j.cub.2008.02.051. PMID 18356055.
- Archibald JM (January 2009). "The puzzle of plastid evolution". Current Biology. 19 (2): R81–8. doi:10.1016/j.cub.2008.11.067. PMID 19174147.
- "How do plants make oxygen? Ask cyanobacteria". Phys.org. Science X. March 30, 2017. Retrieved 2017-10-26.
- Von Nägeli C (1857). Caspary R, ed. "Bericht über die Verhandlungen der 33. Versammlung deutscher Naturforscher und Aerzte, gehalten in Bonn von 18 bis 24 September 1857" [Report on the negotiations on 33 Meeting of German Natural Scientists and Physicians, held in Bonn, 18 to 24 September 1857]. Botanische Zeitung. 15: 749–776.
- Haeckel E (1867). Generelle Morphologie der Organismen. Reimer, Berlin.
- Chatton É (1925). "Pansporella perplexa. Réflexions sur la biologie et la phylogénie des protozoaires". Ann. Sci. Nat. Zool. 10-VII: 1–84.
- Gugger MF, Hoffmann L (March 2004). "Polyphyly of true branching cyanobacteria (Stigonematales)". International Journal of Systematic and Evolutionary Microbiology. 54 (Pt 2): 349–57. doi:10.1099/ijs.0.02744-0. PMID 15023942.
- Howard-Azzeh M, Shamseer L, Schellhorn HE, Gupta RS (November 2014). "Phylogenetic analysis and molecular signatures defining a monophyletic clade of heterocystous cyanobacteria and identifying its closest relatives". Photosynthesis Research. 122 (2): 171–85. doi:10.1007/s11120-014-0020-x. PMID 24917519.
- 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.
- Pringsheim EG (1963). Farblose Algen: Ein Beitrag zur Evolutionsforschung. Gustav Fischer Verlag.
- Riding, R. (2007). "The term stromatolite: towards an essential definition". Lethaia. 32 (4): 321–330. doi:10.1111/j.1502-3931.1999.tb00550.x.
- Garwood, Russell J. (2012). "Patterns In Palaeontology: The first 3 billion years of evolution". Palaeontology Online. 2 (11): 1–14. Retrieved June 25, 2015.
- Lane, Nick (6 February 2010) "First breath: Earth's billion-year struggle for oxygen". New Scientist, pp. 36–9. See accompanying graph as well.
- Corsetti FA, Awramik SM, Pierce D (April 2003). "A complex microbiota from snowball Earth times: microfossils from the Neoproterozoic Kingston Peak Formation, Death Valley, USA". Proceedings of the National Academy of Sciences of the United States of America. 100 (8): 4399–404. Bibcode:2003PNAS..100.4399C. doi:10.1073/pnas.0730560100. PMC . PMID 12682298.
- Gutschick RC, Perry TG (1959-11-01). "Sappington (Kinderhookian) sponges and their environment [Montana]". Journal of Paleontology. 33 (6): 977–985. Retrieved 2007-06-28.
- Riding, Robert. (1991). Calcareous Algae and Stromatolites, p. 32. Springer-Verlag Press.
- Kaneko T, Sato S, Kotani H, Tanaka A, Asamizu E, Nakamura Y, Miyajima N, Hirosawa M, Sugiura M, Sasamoto S, Kimura T, Hosouchi T, Matsuno A, Muraki A, Nakazaki N, Naruo K, Okumura S, Shimpo S, Takeuchi C, Wada T, Watanabe A, Yamada M, Yasuda M, Tabata S (June 1996). "Sequence analysis of the genome of the unicellular cyanobacterium Synechocystis sp. strain PCC6803. II. Sequence determination of the entire genome and assignment of potential protein-coding regions". DNA Research. 3 (3): 109–36. doi:10.1093/dnares/3.3.109. PMID 8905231.
- Tabei Y, Okada K, Tsuzuki M (April 2007). "Sll1330 controls the expression of glycolytic genes in Synechocystis sp. PCC 6803". Biochemical and Biophysical Research Communications. 355 (4): 1045–50. doi:10.1016/j.bbrc.2007.02.065. PMID 17331473.
- Rocap G, Larimer FW, Lamerdin J, Malfatti S, Chain P, Ahlgren NA, Arellano A, Coleman M, Hauser L, Hess WR, Johnson ZI, Land M, Lindell D, Post AF, Regala W, Shah M, Shaw SL, Steglich C, Sullivan MB, Ting CS, Tolonen A, Webb EA, Zinser ER, Chisholm SW (August 2003). "Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche differentiation". Nature. 424 (6952): 1042–7. Bibcode:2003Natur.424.1042R. doi:10.1038/nature01947. PMID 12917642.
- Dufresne A, Salanoubat M, Partensky F, Artiguenave F, Axmann IM, Barbe V, Duprat S, Galperin MY, Koonin EV, Le Gall F, Makarova KS, Ostrowski M, Oztas S, Robert C, Rogozin IB, Scanlan DJ, Tandeau de Marsac N, Weissenbach J, Wincker P, Wolf YI, Hess WR (August 2003). "Genome sequence of the cyanobacterium Prochlorococcus marinus SS120, a nearly minimal oxyphototrophic genome". Proceedings of the National Academy of Sciences of the United States of America. 100 (17): 10020–5. Bibcode:2003PNAS..10010020D. doi:10.1073/pnas.1733211100. PMC . PMID 12917486.
- Meeks JC, Elhai J, Thiel T, Potts M, Larimer F, Lamerdin J, Predki P, Atlas R (2001). "An overview of the genome of Nostoc punctiforme, a multicellular, symbiotic cyanobacterium". Photosynthesis Research. 70 (1): 85–106. doi:10.1023/A:1013840025518. PMID 16228364.
- Herdman M, Janvier M, Rippka R, Stanier RY (1979). "Genome Size of Cyanobacteria". Journal of General Microbiology. 111: 73–85. doi:10.1099/00221287-111-1-73.
- Quintana N, Van der Kooy F, Van de Rhee MD, Voshol GP, Verpoorte R (August 2011). "Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering". Applied Microbiology and Biotechnology. 91 (3): 471–90. doi:10.1007/s00253-011-3394-0. PMC . PMID 21691792.
- Blue green bacteria may help generate 'green' electricity, The Hindu, 21 June 2010
- Joule wins key patent for GMO cyanobacteria that create fuels from sunlight, CO2, and water. Biofuels Digest (2010-09-14). Retrieved on 2011-04-06.
- "Algenol Biofuels exceeds 9,000 gallons of ethanol per year per" (PDF). Algenol Biofuels. 6 March 2013. Archived from the original (PDF) on 20 April 2014.
- Lane J (September 25, 2012). "Take it to the Limit: Algenol and rising yields in advanced biofuels". Biofuels Digest.
- "Nuisance seaweed found to produce compounds with biomedical potential". Sciencedaily.com. 24 May 2012. doi:10.1016/j.chembiol.2012.03.014. Retrieved 1 June 2012.
- "13 August 2013 Federal Register; FDA Approves Natural Blue Color Additive Extracted from Spirulina".
- Verseux C, Baqué M, Lehto K, de Vera JP, Rothschild LJ, Billi D (2016). "Sustainable life support on Mars – the potential roles of cyanobacteria". International Journal of Astrobiology. 15 (1): 65–92. Bibcode:2016IJAsB..15...65V. doi:10.1017/S147355041500021X.
- Thébault L, Lesne J, Boutin JP (1995). "[Cyanobacteria, their toxins and health risks]". Medecine Tropicale. 55 (4): 375–80. PMID 8830224.
- Blue-Green Algae (Cyanobacteria) and their Toxins. Hc-sc.gc.ca (2013-01-30). Retrieved on 2014-04-19.
- Harmful Bloom in Lake Atitlán, Guatemala from NASA Earth Observatory, retrieved on 9 January 2010.
- Caller TA, Doolin JW, Haney JF, Murby AJ, West KG, Farrar HE, Ball A, Harris BT, Stommel EW (2009). "A cluster of amyotrophic lateral sclerosis in New Hampshire: a possible role for toxic cyanobacteria blooms". Amyotrophic Lateral Sclerosis. 10 Suppl 2: 101–8. doi:10.3109/17482960903278485. PMID 19929741.
- Cox PA, Richer R, Metcalf JS, Banack SA, Codd GA, Bradley WG (2009). "Cyanobacteria and BMAA exposure from desert dust: a possible link to sporadic ALS among Gulf War veterans". Amyotrophic Lateral Sclerosis. 10 Suppl 2: 109–17. doi:10.3109/17482960903286066. PMID 19929742.
- Main D (2006). "Toxic Algae Blooms" (PDF). Veterinary Pathologist, South Perth. agric.wa.gov.au. Retrieved 18 November 2014.
- May V, Baker H (1978). "Reduction of toxic algae in farm dams by ferric alum". Techn. Bull. New South Wales Dept of Agriculture. 19: 1–16.
- Spolaore P, Joannis-Cassan C, Duran E, Isambert A (February 2006). "Commercial applications of microalgae". Journal of Bioscience and Bioengineering. 101 (2): 87–96. doi:10.1263/jbb.101.87. PMID 16569602.
- Christaki E, Florou-Paneri P, Bonos E (December 2011). "Microalgae: a novel ingredient in nutrition". International Journal of Food Sciences and Nutrition. 62 (8): 794–9. doi:10.3109/09637486.2011.582460. PMID 21574818.
- Ku CS, Pham TX, Park Y, Kim B, Shin MS, Kang I, Lee J (April 2013). "Edible blue-green algae reduce the production of pro-inflammatory cytokines by inhibiting NF-κB pathway in macrophages and splenocytes". Biochimica et Biophysica Acta. 1830 (4): 2981–8. doi:10.1016/j.bbagen.2013.01.018. PMC . PMID 23357040.
- Mišurcová L, Škrovánková S, Samek D, Ambrožová J, Machů L (2012). "Health benefits of algal polysaccharides in human nutrition". Advances in Food and Nutrition Research. 66: 75–145. doi:10.1016/B978-0-12-394597-6.00003-3. ISBN 978-0-12-394597-6. PMID 22909979.
- Cribbs G (1997). Nature's Superfood: the Blue-Green Algae Revolution (first ed.). Newleaf. ISBN 978-0-7522-0569-4.
- Savage M. The Millennial Project: Colonizing the Galaxy in Eight Easy Steps. Little Brown & Co. ISBN 978-0-316-77163-4.
- Fogg GE, Stewart WD, Fay P, Walsby AE (1973). The Blue-green Algae. London and New York: Academic Press. ISBN 978-0-12-261650-1.
- "Architects of the earth's atmosphere", Introduction to the Cyanobacteria, University of California, Berkeley, 3 February 2006.
- Whitton BA. "Phylum Cyanophyta (Cyanobacteria)". The Freshwater Algal Flora of the British Isles. Cambridge: Cambridge University Press. ISBN 978-0-521-77051-4.
- Pentecost A, Franke U (2010). "Photosynthesis and calcification of the stromatolitic freshwater cyanobacterium Rivularia". Eur. J. Phycol. 45 (4): 345–353. doi:10.1080/09670262.2010.492914.
- Whitton BA, Potts M, eds. (2000). The Ecology of Cyanobacteria: their Diversity in Time and Space. Springer. ISBN 978-0-7923-4735-4.
- "From Micro-Algae to Blue Oil". ParisTech Review. December 2011.
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