Planktothrix formosa

In Einland, Sivonen et al. (1990) performed the first survey of cyanobacterial blooms in 1985-1987 and found that 13 out of 30 bloom samples contained AN. A number of cattle poisonings associated with Anabanea blooms occurred (Sivonen et al., 1990). The first identification of HMAN was isolated from a strain of Planktothrix formosa (Skulberg et al., 1992). AN was also implicated as the causative agent in incidents of fatal canine neurotoxicosis in Ireland (James et al., 1997) and Erance (Gugger et al., 2005). AN and HMAN were found in Anabaena and benthic Planktothrix spp. (Eurey et al., 2003a). AN and HMAN have also been reported in Japan and were isolated from Raphidiopsis mediterranea (Namikoshi et al., 2003). 

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... 

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... 

---