Microcystis aeruginosa Microcystins

In the Slimmer of 1989, Rutland Water, the largest man-made lake in Western Europe and which supplies potable water to approximately 500 000 people in the East of England, contained a heavy bloom of Microcystis aeruginosa. By the end of the summer, a number of sheep and dogs had died after drinking from the bloom and concentrated scum. Analysis revealed that the cyanobacterial bloom material was toxic to laboratory mice, and that rumen contents from a poisoned sheep contained fivemicrocystin variants.Microcystins were detected in waters used for recreation in Australia at concentrations greater than 1 mg per... 

Figure 8. Left The cyclic heptapeptide hepatotoxin microcystin-LA (cyanoginosin-LA) produced by the colonial cyanobacterium Microcystis aeruginosa strain WR-70 (UV-010). MW = 909. Right The cyclic heptapeptide hepatotoxin microcystin-LR (cyanoginosin-LR) produced by a waterbloom of the colonial cyanobacterium Microcystis aeruginosa collected in Lake Akersvatn, Norway, 1984-85 MW=994, 69J1).

Rapid-acting cytotoxin that disrupts cell membranes in the liver (hepatoxin) causing an accumulation of blood in the liver. It is the most toxic of the Microcystins. It is a solid obtained from freshwater blue-green cyanobacteria (Microcystis aeruginosa, Microcystis cyanea). It is heat stable and water soluble. Aqueous solutions are "probably stable" and resistant to chlorine at 100 ppm. It is also soluble in alcohol and acetone. 

G.A. Codd, J.S. Metcalf and A.B. Kenneth, Retention of Microcystis aeruginosa and microcystin by salad lettuce (Lactuca sativa) after spray irrigation with water containing cyanobacteria, Toxicon, 37 (1999) 1181-1185. 

Microcystins LR RR] Microcystis aeruginosa (blue-green PP1 (at InM), PP2A... 

Lawton, L.A., Edwards, C., Beattie, K.A., Pleasance, S., Dear, G.J., and Codd, G.A., 1995. Isolation and charaterization of microcystins from laboratory cultures and environmental samples of Microcystis aeruginosa and from an associated animal toxicosis. Natural Toxins 3 50-57. 

Changes in intracellular calcium homeostasis produced by active metabolites of xenobiotics may cause disruption of the dynamic cytoskeleton. There are a few toxins that cause disruption of the cytoskeleton through mechanisms independent of biotransformation. Microcystin is one of these toxins. Microcystin is produced by the cyanobacterium Microcystis aeruginosa. Similar toxins are produced by other species of cyanobacteria. The hepatocyte is the specific target of microcystin, which enters the cell through a bile-acid transporter. Microcystin covalently binds to serine/threonine protein phosphatase, leading to the hyperphosphorylation of cytoskeletal proteins and deformation of the cytoskeleton (Treinen-Moslen, 2001). 

The microcystins are hepatotoxic produets of freshwater blooms of cyanobacteria of Microcystis, Anabena, and Oscillatoria species (Chen et al, 1993 Luu et al, 1993), with Microcystis aeruginosa being the most common. 

Microcystins were isolated as toxins from Microcystis aeruginosa bloom by Elleman et al. in 1978 and Kusumi et al. in 1987. 

Mohamed, Z., Carmichael, W., An, J., and El-Sharouny, H. (1999). Activated carbon removal efficiency of microcystins in an aqueous cell extract of Microcystis aeruginosa and Oscillatoria tenuis strains isolated from Egyptian freshwaters. Environ. Toxicology, 14(1), 197-201. 

Microcystis aeruginosa (order Chroococcales) accounts for 92% of the compounds isolated from the genus Microcystis (49 compounds total) with 6% coming from Microcystis viridis and 2% from undetermined species. However, it is likely that some variants of the microcystin structure were not tallied in our analysis. 

Microcystin-LR Blue-green algae Microcystis aeruginosa Y Y 1... 

Mortalities of channel catfish, Ictalurus punctatus, have been atfributed to ingestion of toxic blooms of Microcystis aeruginosa (Zimba et al., 2001). The mortalities followed sudden temperature drops of 5°C and necropsy of fish revealed congested hver and spleen tissue, which indicated microcystin toxicosis. Other channel catfish farms in southeastern United States using brackish well water have experienced fish kills that have been reported to be associated with thick blooms of a halophytic cyanobacteria, Anacystis marina rather than Microcystis (Snyder et al., 2002). 

Tillett, D. et al.. Structural organization of microcystin biosynthesis in Microcystis aeruginosa PCC7806 an integrated peptide-poliketide synthetase system, Chem. Biol, 1, 753, 2000. 

Sielaff, H. et al.. The mcyF gene of the microcystin biosynthetic gene cluster from Microcystis aeruginosa encodes an aspartate racemase, Biochem. J., 373, 909, 2003. 

Pearson, L.A. et al.. Inactivation of an ABC transporter gene, ntcyH, results in loss of microcystin production in the cyanobacterium Microcystis aeruginosa PCC 7806, Appl Environ. Microbiol, 70, 6370, 2004. 

Lopez-Rodas, V. et al.. Analysis of polygenic traits of Microcystis aeruginosa (Cyanobacteria) strains by Restricted Maximum Likelihood (REML) procedures 2. Microcystin net production, photosynthesis and respiration, Phycologia, 45, 243, 2006. 

Long, B.M., Jones, G.J., and Orr, P.T., Cellular microcystin content in N-limited Microcystis aeruginosa can be predicted from growth rate, Appl Environ. Microbiol, 67, 278, 2001. 

Oh, H.-M. et al., Microcystin production by Microcystis aeruginosa in a phosphorus-limited chemo-stat,Appl Environ. Microbiol, 66, 176, 2000. 

Orr, P.T. and Jones, G.J., Relationship between microcystin production and cell division rates in nitrogen-limited Microcystis aeruginosa cultures, Limnol. Oceanogr., 43, 1604, 1998. 

Jang, M.-H. et al.. Changes in microcystin production by Microcystis aeruginosa exposed to phyto-planktivorous and omnivorous fish, Aquat. Toxicol., 68, 51, 2004. 

Jones, G.J. and Orr, P.T., Release and degradation of microcystin following algicide treatment of a Microcystis aeruginosa bloom in a recreational lake, as determined by HPLC and protein phosphatase inhibition assay. Water Res., 28, 871, 1994. 

Latvia Microcystis aeruginosa, Aphanizomenon flos-aquae and Anabaena flos-aquae Microcystins [255]... 

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