Microcystin
（重定向自Microcystins）
![NOAA captured this view of Lake Erie in October 2011, during the worst cyanobacteria bloom the lake experienced in decades. Torrential rains increased fertilizer runoff, which promoted the growth of microcystin-producing bacteria.[1][2]](/Images/godic/202501/27/Toxic_Algae_Bloom_in_Lake_Erie0548.jpg")
![Chemical structure of microcystin-LR](/Images/godic/202501/27/Microcystin-LR-structure0548.png")
![A culture of microcystis aeruginosa, a photosynthesizing bacteria](/Images/godic/202501/27/Microcystis_aeruginosa0548.jpeg")
Microcystins (or cyanoginosins) are a class of toxins 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.