Microcystins — or cyanoginosins — are a class of toxins produced by certain freshwater blue-green algae. Over 50 different microcystins have been discovered so far, of which microcystin-LR is the most common. Chemically they are cyclic heptapeptides produced through nonribosomal peptide synthases.

Cyanobacteria can produce microcystins in large quantities during algal blooms which then pose a major threat to drinking and irrigation water supplies, and the environment at large.[3][4]

Toxic Algae Bloom in Lake Erie
Lake Erie in October 2011, during an intense cyanobacteria bloom.[1][2]


Chemical structure of microcystin-LR

Microcystins — or cyanoginosins — are a class of toxins[5] produced by certain freshwater cyanobacteria; primarily Microcystis aeruginosa but also other Microcystis, as well as members of the Planktothrix, Anabaena, Oscillatoria and Nostoc genera. Over 50 different microcystins have been discovered so far, of which microcystin-LR is the most common. Chemically they are cyclic heptapeptides produced through nonribosomal peptide synthases.[6]

Microcystin-LR is the most toxic form of over 80 known toxic variants, and is also the most studied by chemists, pharmacologists, biologists, and ecologists. Microcystin-containing 'blooms' are a problem worldwide, including China, Brazil, Australia, South Africa,[7][8][9][10][11][12][13][14] the United States and much of Europe. Hartebeespoort Dam in South Africa is one of the most contaminated sites in Africa, and possibly in the world.

Microcystins contain several uncommon non-proteinogenic amino acids such as dehydroalanine derivatives and the uncommon β-amino acid ADDA. Microcystins covalently bond to and inhibit protein phosphatases PP1 and PP2A and can thus cause pansteatitis.[15]


Microcystis aeruginosa.jpeg
A culture of M. aeruginosa, a photosynthesizing bacterium

The microcystin-producing Microcystis is a genus of freshwater cyanobacteria and is projected to thrive with warmer climate conditions, such as the rise of water temperatures or in stagnant waters, and through the process of eutrophication (oversupply of nutrients).[4] A study concluded in 2009 that climate change can catalyze the global expansion of cyanobacterial blooms.[3] The EPA reported in 2013, that climate change and changing environmental conditions are associated with harmful algae growth and may negatively impact human health, and the economy for communities across the US and around the world.[16]

Evidence developed at the University of Heidelberg suggests that in particular dissolved reactive phosphorus promotes additional growth.[17]

Exposure pathways

Humans are exposed by swallowing, skin contact with or inhaling contaminated water.[18] Microcystins are chemically stable over a wide range of temperature and pH, possibly as a result of their cyclic structure.[19] Microcystin-producing bacteria algal blooms can overwhelm the filter capacities of water treatment plants. Some evidence shows the toxin can be transported by irrigation into the food chain,[20][21]

Lake Erie blooms

In 2011, a record outbreak of blooming microcystis occurred in Lake Erie, in part related to the wettest spring on record, and expanded lake bottom dead zones, reduced fish populations, fouled beaches, and the local tourism industry which generates more than $10 billion in revenue annually.[1]

In August 2014, the City of Toledo, Ohio detected unsafe levels of microcystin in its water supply due to harmful algal blooms in Lake Erie, the shallowest of the Great Lakes. They issued a DO NOT DRINK OR BOIL water advisory to approximately 500,000 people.[22][23] An Ohio state task force found that Lake Erie received more phosphorus than any other Great Lake, both from crop land, due to the farming practices, and from urban water-treatment centres[17] Algal blooms have been occurring more frequently, and scientists had predicted this significant bloom of blue-green algae to peak in early September 2014.[24][25]

San Francisco Bay Area

In 2016, microcystin had been found in San Francisco Bay Area shellfish in seawater, apparently from freshwater runoff, exacerbated by drought.[26]


In 2018, the Iowa Department of Natural Resources found microcystins at levels of .3 µg/L, or micrograms per liter, which is equivalent to .3 parts per billion in the raw water supplies of 15 out of 26 public water systems tested.[27]

Human health effects upon exposure

Microcystins cannot be broken down by standard proteases like pepsin, trypsin, collagenase, and chymotrypsin due to their cyclic chemical nature.[19] They are hepatotoxic, i.e. able to cause serious damage to the liver. Once ingested, microcystin travels to the liver via the bile acid transport system, where most is stored, though some remains in the blood stream and may contaminate tissue.[28][29] Acute health effects of Microcystin-LR are abdominal pain, vomiting and nausea, diarrhea, headache, blistering around the mouth, and after inhalation sore throat, dry cough, and pneumonia.[30] There appears to be inadequate information to assess the carcinogenic potential of microcystins by applying EPA Guidelines for Carcinogen Risk Assessment. A few studies suggest a relationship may exist between liver and colorectral cancers and the occurrence of cyanobacteria in drinking water in China.[31][32][33][34][35][36] Evidence is, however, limited due to limited ability to accurately assess and measure exposure.

The impact on patients with a compromised immune system is not yet fully known, but as of 1991 it was starting to raise some concern.[37]

In mice, high dose green tea might have a protective effect against microcystin induced toxicity[38][39]


In the US, the EPA issued a health advisory in 2015.[40] A ten day Health Advisory was calculated for different ages which is considered protective of non-carcinogenic adverse health effects over a ten-day exposure to microcystins in drinking water: 0.3 μg/L for bottle-fed infants and young children of pre-school age and 1.6 μg/L for children of school age through adults.[40]: 28–29

See also


  1. ^ a b Michael Wines (March 14, 2013). "Spring Rain, Then Foul Algae in Ailing Lake Erie". The New York Times.
  2. ^ Joanna M. Foster (November 20, 2013). "Lake Erie is Dying Again, and Warmer Waters and Wetter Weather are to Blame". ClimateProgress.
  3. ^ a b Paerl HW, Huisman J (February 2009). "Climate change: a catalyst for global expansion of harmful cyanobacterial blooms". Environmental Microbiology Reports. 1 (1): 27–37. doi:10.1111/j.1758-2229.2008.00004.x. PMID 23765717.
  4. ^ a b "Increasing toxicity of algal blooms tied to nutrient enrichment and climate change". Oregon State University. October 24, 2013.
  5. ^ Dawson, R.M (1998). "the toxicology of microcystins". Toxicon. 36 (7): 953–962. doi:10.1016/S0041-0101(97)00102-5.
  6. ^ Ramsy Agha, Samuel Cirés, Lars Wörmer and Antonio Quesada (2013). "Limited Stability of Microcystins in Oligopeptide Compositions of Microcystis aeruginosa (Cyanobacteria): Implications in the Definition of Chemotypes". Toxins. 5 (6): 1089–1104. doi:10.3390/toxins5061089. PMC 3717771. PMID 23744054.CS1 maint: Uses authors parameter (link)
  7. ^ Bradshaw D, Groenewald P, Laubscher R, Nannan N, Nojilana B, Norman B, Pieterse D, Schneider M (2003). Initial Burden of Disease Estimates for South Africa, 2000 (PDF). Cape Town: South African Medical Research Council. ISBN 978-1-919809-64-9.
  8. ^ Fatoki, O.S., Muyima, N.Y.O. & Lujiza, N. 2001. Situation analysis of water quality in the Umtata River Catchment. Water SA, (27) Pp 467-474.
  9. ^ Oberholster PJ, Botha AM, Cloete TE (2005). "An overview of toxic freshwater cyanobacteria in South Africa with special reference to risk, impact, and detection by molecular marker tools". Biokemistri. 17 (2): 57–71. doi:10.4314/biokem.v17i2.32590.
  10. ^ Oberholster PJ, Botha AM (2007). "Use of PCR based technologies for risk assessment of a winter cyanobacterial bloom in Lake Midmar, South Africa". African Journal of Biotechnology. 6 (15): 14–21.
  11. ^ Oberholster, P. 2008. Parliamentary Briefing Paper on Cyanobacteria in Water Resources of South Africa. Annexure "A" of CSIR Report No. CSIR/NRE/WR/IR/2008/0079/C. Pretoria. Council for Scientific and Industrial Research (CSIR).
  12. ^ Oberholster, P.J.; Cloete, T.E.; van Ginkel, C.; Botha, A-M.; Ashton, P.J. (2008). "The use of remote sensing and molecular markers as early warning indicators of the development of cyanobacterial hyperscum crust and microcystin-producing genotypes in the hypertrophic Lake Hartebeespoort, South Africa" (PDF). Pretoria: Council for Scientific and Industrial Research. Archived from the original (PDF) on 2014-08-11.
  13. ^ Oberholster, P.J.; Ashton, P.J. (2008). "State of the Nation Report: An Overview of the Current Status of Water Quality and Eutrophication in South African Rivers and Reservoirs" (PDF). Pretoria: Council for Scientific and Industrial Research. Archived from the original (PDF) on 2014-08-08.
  14. ^ Turton, A.R. 2015. Water Pollution and South Africa’s Poor. Johannesburg: South African Institute of Race Relations. http://irr.org.za/reports-and-publications/occasional-reports/files/water-pollution-and-south-africas-poor
  15. ^ http://www.pwrc.usgs.gov/health/rattner/rattner_blackwaternwr.cfm
  16. ^ "Impacts of Climate Change on the Occurrence of Harmful Algal Blooms" (PDF). EPA. 2013.
  17. ^ a b Suzanne Goldenberg (August 3, 2014). "Farming practices and climate change at root of Toledo water pollution". The Guardian.
  18. ^ How are humans exposed to cyanobacteria and cyanotoxins? EPA, retrieved 12 Nov 2018
  19. ^ a b Somdee, Theerasak; Thunders, Michelle; Ruck, John; Lys, Isabelle; Allison, Margaret; Page, Rachel (2013). "Degradation of [Dha7]MC-LR by a Microcystin Degrading Bacterium Isolated from Lake Rotoiti, New Zealand". Isrn Microbiology. 2013: 1–8. doi:10.1155/2013/596429. PMID 23936728.
  20. ^ Codd GA, Metcalf JS, Beattie KA (August 1999). "Retention of Microcystis aeruginosa and microcystin by salad lettuce (Lactuca sativa) after spray irrigation with water containing cyanobacteria". Toxicon. 37 (8): 1181–5. doi:10.1016/S0041-0101(98)00244-X. PMID 10400301.
  21. ^ Abe, Toshihiko; Lawson, Tracy; Weyers, Jonathan D. B.; Codd, Geoffrey A. (August 1996). "Microcystin-LR Inhibits Photosynthesis of Phaseolus vulgaris Primary Leaves: Implications for Current Spray Irrigation Practice". New Phytologist. 133 (4): 651–8. doi:10.1111/j.1469-8137.1996.tb01934.x. JSTOR 2558683.
  22. ^ "Algal bloom leaves 500,000 without drinking water in northeast Ohio". Reuters. August 2, 2014.
  23. ^ Rick Jervis, USA TODAY (August 2, 2014). "Toxins contaminate drinking water in northwest Ohio".
  24. ^ John Seewer. "Don't drink the water, says 4th-largest Ohio city".
  25. ^ "Toxins in water leads to state of emergency in Ohio". Ohio Standard. Retrieved 2 August 2014.
  26. ^ John Raphael BEWARE: High Levels of Freshwater Toxin Found in Shellfish from San Francisco Bay Oct 28, 2016. Nature World News
  27. ^ Kate Payne Toxic Bacteria Blooms Impacting Water Systems Across Iowa, DNR Survey Shows. November 1, 2018. National Public Radio
  28. ^ Falconer, Ian R. (1998). "Algal Toxins and Human Health". In Hrubec, Jiři. Quality and Treatment of Drinking Water II. The Handbook of Environmental Chemistry. 5 / 5C. pp. 53–82. doi:10.1007/978-3-540-68089-5_4. ISBN 978-3-662-14774-0.
  29. ^ Falconer, I.R. 2005. Cyanobacterial Toxins of Drinking Water Supplies: Cylindrospermopsins and Microcystins. Florida: CRC Press. 279 pages.
  30. ^ What health risks do humans face as a result of exposure to cyanotoxins? EPA, retrieved 12 Nov 2018
  31. ^ Humpage AR, Hardy SJ, Moore EJ, Froscio SM, Falconer IR (October 2000). "Microcystins (cyanobacterial toxins) in drinking water enhance the growth of aberrant crypt foci in the mouse colon". Journal of Toxicology and Environmental Health, Part A. 61 (3): 155–65. doi:10.1080/00984100050131305. PMID 11036504.
  32. ^ Ito E, Kondo F, Terao K, Harada K (September 1997). "Neoplastic nodular formation in mouse liver induced by repeated intraperitoneal injections of microcystin-LR". Toxicon. 35 (9): 1453–7. doi:10.1016/S0041-0101(97)00026-3. PMID 9403968.
  33. ^ Nishiwaki-Matsushima R, Nishiwaki S, Ohta T, et al. (September 1991). "Structure-function relationships of microcystins, liver tumor promoters, in interaction with protein phosphatase". Japanese Journal of Cancer Research. 82 (9): 993–6. doi:10.1111/j.1349-7006.1991.tb01933.x. PMC 5918597. PMID 1657848.
  34. ^ Ueno Y, Nagata S, Tsutsumi T, et al. (June 1996). "Detection of microcystins, a blue-green algal hepatotoxin, in drinking water sampled in Haimen and Fusui, endemic areas of primary liver cancer in China, by highly sensitive immunoassay". Carcinogenesis. 17 (6): 1317–21. doi:10.1093/carcin/17.6.1317. PMID 8681449.
  35. ^ Yu S-Z (1989). "Drinking water and primary liver cancer". In Z.Y. Tang; M.C. Wu; S.S. Xia. Primary Liver Cancer. New York: China Academic Publishers. pp. 30–7. ISBN 978-0-387-50228-1.
  36. ^ Zhou L, Yu H, Chen K (June 2002). "Relationship between microcystin in drinking water and colorectal cancer". Biomedical and Environmental Sciences. 15 (2): 166–71. PMID 12244757.
  37. ^ Doyle P. (1991). The Impact of AIDS on the South African Population. AIDS in South Africa: The Demographics and Economic Implications. Centre for Health Policy, University of the Witwatersrand, Johannesburg, South Africa.
  38. ^ Xu, C; Shu, W. Q.; Cao, J; Qiu, Z. Q.; Zhao, Q; Chen, J. A.; Zeng, H; Fu, W. J. (2007). "绿茶对微囊藻毒素诱导肝肾氧化损伤的拮抗效应" [Antagonism effects of green tea against microcystin induced oxidant damage on liver and kidney]. 中华预防医学杂志 (in Chinese). 41 (1): 8–12. doi:10.3760/j:issn:0253-9624.2007.01.003. PMID 17484202.(subscription required)
  39. ^ Xu, Chuan; Shu, Wei-Qun; Qiu, Zhi-Qun; Chen, Ji-An; Zhao, Qing; Cao, Jia (2007). "Protective effects of green tea polyphenols against subacute hepatotoxicity induced by microcystin-LR in mice". Environmental Toxicology and Pharmacology. 24 (2): 140–8. doi:10.1016/j.etap.2007.04.004. PMID 21783802.
  40. ^ a b Drinking Water Health Advisory for the Cyanobacterial Microcystin Toxins U.S. Environmental Protection Agency Office of Water, EPA Document Number: 820R15100, 75pp, 15 June 2015

Further reading

  • National Center for Environmental Assessment. Toxicological Reviews of Cyanobacterial Toxins: Microcystins LR, RR, YR, and LA (NCEA-C-1765)

External links

ADDA (amino acid)

(all-S,all-E)-3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid is a non-proteinogenic amino acid found in toxins made by cyanobacteria. Toxins which include this amino acid are microcystin and nodularin.

Aphanizomenon flos-aquae

Aphanizomenon flos-aquae is a brackish and freshwater species of cyanobacteria found around the world, including the Baltic Sea and the Great Lakes.

Canadian Reference Materials

Canadian Reference Materials (CRM) are certified reference materials of high-quality and reliability produced by the National Metrology Institute of Canada – the National Research Council Canada. The NRC Certified Reference Materials program is operated by the Measurement Science and Standards portfolio and provides CRMs for environmental, biotoxin, food, nutritional supplement, and stable isotope analysis. The program was established in 1976 to produce CRMs for inorganic and organic marine environmental analysis and remains internationally recognized producer of CRMs.


Colestyramine (INN) or cholestyramine (USAN) (trade names Questran, Questran Light, Cholybar, Olestyr) is a bile acid sequestrant, which binds bile in the gastrointestinal tract to prevent its reabsorption. It is a strong ion exchange resin, which means it can exchange its chloride anions with anionic bile acids in the gastrointestinal tract and bind them strongly in the resin matrix. The functional group of the anion exchange resin is a quaternary ammonium group attached to an inert styrene-divinylbenzene copolymer.

Colestyramine removes bile acids from the body by forming insoluble complexes with bile acids in the intestine, which are then excreted in the feces. As a result of this loss of bile acids, more plasma cholesterol is converted to bile acids in the liver to normalise levels. This conversion of cholesterol into bile acids lowers plasma cholesterol levels.


Cyanopeptolins are a class of oligopeptides produced by Microcystis and Planktothrix algae strains, and can be neurotoxic. The production of cyanopeptolins occurs through nonribosomal peptides synthases (NRPS).


Cyanotoxins are toxins produced by bacteria called cyanobacteria (also known as blue-green algae). Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under high concentration of phosphorus conditions, they reproduce exponentially to form blooms. Blooming cyanobacteria can produce cyanotoxins in such concentrations that they poison and even kill animals and humans. Cyanotoxins can also accumulate in other animals such as fish and shellfish, and cause poisonings such as shellfish poisoning.

Among cyanotoxins are some of the most powerful natural poisons known, including poisons which can cause rapid death by respiratory failure. The toxins include potent neurotoxins, hepatotoxins, cytotoxins, and endotoxins. Despite the similarity in name, they are not cyanides. Recreational exposure to cyanobacteria can result in gastro-intestinal and hay fever symptoms or pruritic skin rashes. Exposure to the cyanobacteria neurotoxin BMAA may be an environmental cause of neurodegenerative diseases such as ALS, Parkinson's Disease and Alzheimer's Disease. There is also an interest in the military potential of biological neurotoxins such as cyanotoxins, which "have gained increasing significance as potential candidates for weaponization."The first published report that blue-green algae or cyanobacteria could have lethal effects appeared in Nature in 1878. George Francis described the algal bloom he observed in the estuary of the Murray River in Australia, as "a thick scum like green oil paint, some two to six inches thick." Wildlife which drank the water died rapidly and terribly. Most reported incidents of poisoning by microalgal toxins have occurred in freshwater environments, and they are becoming more common and widespread. For example, thousands of ducks and geese died drinking contaminated water in the midwestern United States. In 2010, for the first time, marine mammals were reported to have died from ingesting cyanotoxins.


Cyclamides are a class of oligopeptides, produced by cyanobacteria algae strains, such as microcystis aeruginosa and can be toxic. Cyclamides are synthesized through ribosomic pathways.


Dadih (Indonesian: Dadih), a traditional fermented milk popular among people of West Sumatra, Indonesia, is made by pouring fresh raw unheated buffalo milk into a bamboo tube capped with a banana leaf, and allowing it to ferment spontaneously at room temperature for two days.

The milk is fermented by indigenous lactic bacteria of the buffalo milk. Its natural fermentation provides different strains of indigenous lactic bacteria involved in each fermentation. The natural indigenous lactic acid bacteria observed in dadih could be derived from the bamboo tubes, buffalo milk or banana leaves involved in milk fermentation.

Dadih is usually eaten for breakfast, mixed together with ampiang (traditional glutinous rice krispies) and palm sugar. Dadih can also be eaten with hot rice and sambal.Some studies on probiotic properties of indigenous strains isolated from dadih fermented milk demonstrated to exhibit antimutagenic, acid, and bile tolerance as well as antipathogenic properties. Natural wild strains isolated from dadih show inhibitory, competitive and displacing properties against pathogens, and they are promising candidates for future probiotics. Viable cells of Lactobacillus plantarum strains from dadih as well as active metabolism play important roles in removing microcystin-LR, cyanobacterial toxin, and natural wild strain of Lactobacillus plantarum from dadih has the highest removal abilities as compared to the other commercial probiotic strains. This finding offers new and economical tools for decontaminating microcystin containing water.

Lake Bernard Frank

Lake Bernard Frank (Lake Frank), is a 54-acre (220,000 m2) reservoir on the North Branch of Rock Creek in Derwood, Maryland, USA, just east of Rockville. It is named after Bernard Frank, a wilderness activist and a co-founder of The Wilderness Society. The lake's boundaries are, approximately, Route 28, East Gude Drive, Avery Road, and Muncaster Mill Road. Lake Frank was created in 1966 to aid in flood and sediment control, as well as to provide recreation. It has an earthen dam, installed in 1967, on its southern side. It was created as a sister lake to Lake Needwood. Lake Frank is owned by the Maryland-National Capital Park and Planning Commission (M-NCPPC).

The lake's secluded location within Rock Creek Regional Park is another of its assets. Visitors to the lake must bike or walk about 1/4 of a mile from all parking lots to get to the lakeshore. The Lake Frank & Meadowside Trails surround the lake, making it a favorite hiking spot. Also, locals enjoy fishing from the shoreline, though a license is needed to do so. However, swimming, boating, and ice skating are prohibited.

The main trail around Lake Frank, the Lakeside Trail, is a 3​1⁄4 mile long loop. Approximately 2/3 of the trail is unpaved and traverses the woods surrounding the lake. The other part of the trail is wider and paved. At the approximate half-way point of the trail, there is a creek that must be crossed. Though there are a group of rocks which form a bridge-like path across, the creek may be impassable depending on the water level.

Lake Needwood

Lake Needwood is a 75-acre (300,000 m2) reservoir in Derwood, Maryland, USA. Located east of Rockville, in the eastern part of Montgomery County, it is situated on Rock Creek. The lake was created to provide flood control. It also protects the water quality of the creek by functioning as a retention basin to trap sediment from storm-water runoff.

The lake is part of Rock Creek Regional Park. Visitors can rent pedal boats, rowboats, and canoes, and a flat-bottom pontoon boat, the Needwood Queen, is available for rides. Also, the picnic areas surrounding the lake are popular locations for various events. Other park features include a visitors center and snack bar, hiking and biking trails, playgrounds, an archery range and Needwood Golf Course. About one mile (1.6 km) southeast is Lake Needwood's sister lake, Lake Frank.

The Rock Creek Trail begins at Lake Needwood and can be followed along the course of Rock Creek, ending at the Potomac River in Washington, D.C.

Lake Winnipeg algae threat

In the last 30 years Lake Winnipeg has experienced a steady surge of blue-green algae growth and although algae grows naturally in the lake, excessive blue-green algae blooms are caused by high ratio levels of nitrogen and phosphorus draining into the lake via rivers and surface runoff. Up to five and a half million people rely on the health of Lake Winnipeg. The lake is an economical powerhouse that supports a $100 million a year tourism industry and a $25 million a year fishing industry. Healthy algae populations play an important role in keeping lake Winnipeg's ecological systems balanced. Green algae provides food for zooplankton, which are then eaten by larger fish in the lake. However the toxins that blue-green algae release can destroy fresh water ecosystems and can be dangerous for humans and other species. Very high levels of the algae toxin microcystin closed Victoria Beach off from the public in the summer of 2003. Grand Beach and other surrounding settlements along the lake are often closed for a short time during summer months due to E. coli and algae-toxin related threats. Immense algae blooms have appeared in the northern part of Lake Winnipeg in the last decade with hundreds of square kilometers of the lake covered with a thick toxic layer of blue-green algae. Local residents in surrounding communities say the blue-green algae is well known for creating deadly water conditions in prairie dugouts and have been known to even kill livestock. Commercial and aboriginal fishermen on the lake often find their nets temporarily disabled during the summer months because of the thick algae conditions. The Lake Winnipeg algae blooms are considered the worst algae problem of any large freshwater lake in the world.


Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria. It is the most toxic of the microcystins.


Microcystinase is a protease that selectively degrades Microcystin, an extremely potent cyanotoxin that results in marine pollution and human and animal food chain poisoning. The enzyme is naturally produced by a number of bacteria isolated in Japan and New Zealand. As of 2012, the chemical structure of this enzyme has not been scientifically determined. The enzyme degrades the cyclic peptide toxin microcystin into a linear peptide, which is 160 times less toxic. Other bacteria then further degrade the linear peptide.


Microcystis is a genus of freshwater cyanobacteria which includes the harmful algal bloom Microcystis aeruginosa. The cyanobacteria can produce neurotoxins and hepatotoxins, such as microcystin and cyanopeptolin.

Microcystis aeruginosa

Microcystis aeruginosa is a species of freshwater cyanobacteria which can form harmful algal blooms of economic and ecological importance. They are the most common toxic cyanobacterial bloom in eutrophic fresh water. Cyanobacteria produce neurotoxins and peptide hepatotoxins, such as microcystin and cyanopeptolin.


Planktothrix is a genus of filamentous cyanobacteria (often called blue-green algae). P. agardhii is regarded as a type species of the genus. Like all the Oscillatoriales, Planktothrix species have no heterocyst and no akinetes, but are unique because they are planktonic, solitary trichome and have gas vacuoles. Before the work of Suda et al., some species of the taxon were grouped within the genus Oscillatoria. A tremendous body of work on Planktothrix ecology and physiology has been done by Anthony E. Walsby, and the 55.6 kb microcystin synthetase gene have been sequenced.P. agardhii and P. rubescens are commonly observed in lakes of the Northern Hemisphere where they are known producers of potent hepatotoxins called microcystins.

Protein phosphatase 1

Protein phosphatase 1 (PP1) belongs to a certain class of phosphatases known as protein serine/threonine phosphatases. This type of phosphatase includes metal-dependent protein phosphatases (PPMs) and aspartate-based phosphatases. PP1 has been found to be important in the control of glycogen metabolism, muscle contraction, cell progression, neuronal activities, splicing of RNA, mitosis, cell division, apoptosis, protein synthesis, and regulation of membrane receptors and channels.

Spirulina (dietary supplement)

Spirulina is a biomass of cyanobacteria (blue-green algae) that can be consumed by humans and other animals. The two species are Arthrospira platensis and A. maxima.

Cultivated worldwide, Arthrospira is used as a dietary supplement or whole food. It is also used as a feed supplement in the aquaculture, aquarium, and poultry industries.

Steroidobacter flavus

Steroidobacter flavus is a microcystin-degrading bacterium from the genus of Steroidobacter which has been isolated from forest soil from the Hainan Island in China.


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