Planktothrix Oscillatoria

Microcystis, Nostoc, and Oscillatoria (Planktothrix). Cyanobacteria toxins (cyanotoxins) include cytotoxins and biotoxins (neurotoxins anatoxin-a, anatoxin-a(s) and saxitoxins, and the hepatotoxins microcystins MCs, and nodularins), with biotoxins being responsible for acute lethal, acute chronic, and subchronic poisonings of wild/domestic animals and humans. In most of the reported cases, afflicted animals consumed water from water bodies where there was an obvious presence of cyano-bacterial scum on the water surface. More recent measurements of cyanobacterial toxins using sensitive modem analytical methods have often revealed high frequencies of toxic blooms even when animal poisonings have not been reported. 

Cyanobacteria -/Anafaaena spp. and Oscillatoria sp. (Planktothrix spp.) Cyanobacteria - Planktothrix spp. 

Homoanatoxin-a, obtained from various freshwater cyanobacteria, is a relatively rare natural analog of anatoxin-a for which the C-11 side chain is extended by one methylene unit (Figure 6.4). It was originally isolated from Planktothrix sp. (formerly Oscillatoria) in 1992 [51]. It has recently been isolated from Raphidiopsis mediterranea Skuja from Japan [52] and Planktothrix (formerly Oscillatoria) formosa blooms in Ireland [53]. 

In 1992, a methylene analogue of AN, named homoanatoxin-a (HMAN), was isolated from Planktothrix (Oscillatoria) formosa in Norway (Skulberg et al. 1992). Interestingly, HMAN... 

Microcystins and Nodularins Mieroeystins (MC) are widely distributed eyanotoxins, and have often been implicated in aeeidental human and animal poisonings. They are produeed by several genera, including the planktonic Microcystis, Planktothrix, Anabaena species, and the benthic Oscillatoria. Nodularins are only produced by the species Nodularia spumigena, whieh occurs in brackish waters, essentially in the Baltie Sea, Australia, and New Zealand. 

Anatoxins are produced mainly by Anabaena species, but also by Aphanizomenon, Planktothrix, Cylindrospermum, Microcystis, and the benthic Oscillatoria and Phormidium (Sivonen and Jones, 1999). 

In 1992, a methylene analogue of AN, homoanatoxin-a (HMAN) (Figure 38.1 R=C2H5), was isolated from Planktothrix (Oscillatoria) formosa in Norway (Skulberg et al., 1992). AN and HMAN act by enhancing the release of acetylcholine (ACh) from peripheral cholinergic nerves (Lilleheil et al, 1997). HMAN is much less common than AN but has been found in Ireland and Japan (Furey et al., 2003a), (Namikoshi et al., 2003). Anatoxin-a(s) is structurally umelated to AN but was also... 

Anatoxin-a is a potent, fast-acting nemotoxin. It occurs worldwide in freshwaters and is produced by several genera of cyanobacteria, including Anabaena, Aphanizomenon, Microcystis, Planktothrix, Raphidiopsis, Arthrospira, Cylindrospermum, Phormidium, Nostoc, and Oscillatoria (Osswald et al., 2007). Exposures occur mainly through consumption of contaminated drinking water but have also occurred from recreational use of lakes and through contaminated dietary supplements (Rogers et al., 2005). 

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