Anatoxin isolation

Anatoxins. Neurotoxins produced by filamentous Anabaena flos-aquae are called anatoxins (ANTXS) 15). Currently two anatoxins, from different strains of A. flos-aquae, have been isolated and at least partially characterized. ANTX-A from strain (single filament isolate) NRC-44-1 is the first toxin from a freshwater... 

Figure 3. (+)-Anatoxin-a (AnTx) and ACh induced single ion channel currents in isolated frog muscle fibers. Open channels with 32 pS conductance are downward deflections (inward current at hyperpolarized potentials). The currents shown on the left are all at one potential. The duration of channel open events had a similar voltage-dependence for both ACh and (+)-anatoxin-a. With ACh, the events were most often singular, while with (+)-anatoxin-a the events were shorter and were more frequently paired so that the mean duration of the exponentially distributed open times and selected membrane holding potentials was approximately one-half, independent of the concentration of the agonist applied.

Alteromonas species producing sodium channel blockers, 80r,82 Anabaena flos-aquae neurotoxins, 88 toxic principle, 108 Analyses, definition, 43 Anatoxin(s) isolation, 88 types, 88,91 Anatoxin a... 

Parsons and coworkers [174] have published a route to anatoxin-o, which was isolated from strains of freshwater blue-green algae Anabaena flos aqua and is responsible for the death of livestock, waterfowl, and fish [175]. The sequence started... 

The main genera responsible for freshwater toxic blooms are Microcystis, Anabaena, Aphanizomenon and Oscillatoria. Toxins produced include 1. anatoxins, alkaloids and peptides of Anabaena 2. the peptide microcystin and related peptides of Microcystis 3. aphantoxins, compounds of Aphanizomenon with properties similar to some paralytic shellfish poisons. Properties of Oscillatoria toxin suggest they are peptides similar to those of Microcystis. Microcystis toxins are peptides (M.W. approx. 1200) which contain three invariant D-amino acids, alanine, erythro-3-methyl aspartic and glutamic acids, two variant L-amino acids, N-methyl dehydro alanine and a 3-amino acid. Individual toxic strains have one or more multiples of this peptide toxin. The one anatoxin characterized is a bicylic secondary amine called anatoxin-a (M.W. 165). The aphantoxin isolated in our laboratory contains two main toxic fractions. On TLC and HPLC the fractions have the same characteristics as saxitoxin and neosaxitoxin. 

Alkaloid Toxins. Only one alkaloid toxin has been chemically defined from the cyanobacteria. This is the secondary amine, 2-acetyl-9-azabicyclo (4-2-1) non-2-ene, called anatoxin-a. It is isolated from the filamentous strain Anabaena flos-aquae NRG-44-1 (18,19). 

A variety of other tropane alkaloids have been isolated of which the most important is anatoxin-A, a highly toxic nACh-R agonist and depolarizing neuromuscular blocking agent deriving from Anabaena cyanobacterium species that can contaminate inland waters. 

Anatoxin-a, the first highly potent cyanotoxin to have its structure and absolute stereochemistry elucidated, was originally isolated from a unialgal clone of Anabaena Jlos-aquae (NRC-44h) [5]. The structure was confirmed by X-ray crystallographic data for the N-acetyl derivative [11] and additional studies have since provided further proof for the structure and stereochemistry (for example, [12]). Anatoxin-a is an unsymmetrical bicyclic secondary amine, and was the first naturally occurring alkaloid discovered to contain a 9-azabicyclo[4,2,l]nonane (homotropane) skeleton. Homotropanes are one-carbon analogs of the tropanes and, as such, are structurally closely related to the well-known alkaloid cocaine. 

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]. 

Anatoxin-a is a natnrally occnrring nenrotoxic alkaloid, prodnced by several strains of cyanobacteria. Originally, the species, Anabaena flos aquae, was the sonrce of the toxin, which was conse-qnently named anatoxin-a. Since its isolation (Devlin et al. 1977) and characterisation as a (lA,(5A)-2-acetyl-9-azabicyclo[4.2.1]nonane (Hnber et al. 1972 Koskinen and Rapoport 1985) in the 1970s, anatoxin-a (1 Fig. 7.1 A) has stimnlated the scientific commnnity worldwide. While synthetic chemists devised methods for the constmction of the novel 9-azabicyclo[4.2.1]nonane ring system, medicinal chemists were intrigned by its powerful biological activity. 

Anatoxin-a was first isolated fmmAnabaenaflos-aquae in 1976 (Devlin et al. 1977). The isolation and enriehment of AN from eultuied material involved adjustment of the algae suspension to pH 5 prior to lyophilization. The residual material was then extracted with methanol containing dilute hydrochloric acid. After evaporation the resulting syrup was neutralized and extracted with benzene... 

Carmichael, W.W, and Gorham, ER. 1978. Anatoxins from clones of Anabaena flos-aquae isolated from lakes in western Canada. Mittint Verein Theor Angew Limon 21, 285—295. 

Kangatharalingam, N., and Priscu, J. 1993. Isolation and verification of anatoxin-a producing clones of Anabaena flos-aquae (lyngb.) de Breb. from a eutrophic lake.FEMSMicrobiolEcol 12, 127-130. 

A neurotoxic natural product, anatoxin-a(s) (261), was isolated from several biological sources, including a blue-green alga (330, 331). 

Anatoxin-a(s) (61) is a potent neurotoxin, first isolated from the cyanobacterium A. flos-aqmeP Despite the name of this metabolite, it is structurally unrelated to anatoxin-a (62). The structure was not solved until 1989 through a combination of H, and NMR experiments on a sample of anatoxin-a(s) that had been... 

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 (AN) has not been implicated in human toxicosis but there have been many confirmed incidenfs where fhis toxin led to rapid animal fatalities following the consumption of lakewaters containing cyanobacteria. AN was isolated and determined to be a bicychc secondary amine,... 

Anatoxin A is the fast-acting and highly effective poison of the cyanobacterium Anabaenaflos-aquae, which is ubiquitous in freshwater. Anatoxin A, also known as Very Fast Death Factor , was isolated from Anabaenaflos-aquae in 1977 by Paul Gorham at the National Research CoimcU in Ottawa. [553,554] The structure had already been determined in 1972 by X-ray analysis of its N-acetyl derivative. [555] Later, the presence of anatoxin A was detected in a range of other toxic strains of Oscillatoria, Anabaena circinalis, Aphanizomenonflos-aquae, Cylindorsperum pp. and Raphidiopsis mediterranea. 

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