Gambierdiscus toxicus toxin

Although Gambierdiscus toxicus was the first dinofiagellate species to be involved in the genesis of ciguateric toxins, other toxic dinofiagellates have been... 

Cultures of Gambierdiscus toxicus have been obtained in several laboratories (14,17-19). These cultures produce large amounts of maitotoxin and low amounts of lipid-soluble CTx-like toxin. However, in most cases, this toxin has not been unequivocally identified as CTx. The only firm evidence that cultures of Gambierdiscus toxicus produce CTx was provided by Baden et al. (20) who used radioimmunoassays and electrophysiological experiments to characterize the toxin. It is possible that cultured Gambierdiscus toxicus produce only trace amounts of CTx and that levels of production comparable to those found in natural populations are dependent on yet undefined environmental parameters. 

Preliminary results on toxicity of 3 species of Caribbean dinoflagellates have been reported, namely those on Gambierdiscus toxicus (25), Prorocentrum concavum (as cf. lima) (26), and mexicanum (as rhathymum) (27). A more detailed description of the effects of ether-soluble and water-soluble toxins from the same strain of toxicus on guinea pig ilea are presented elsewhere in... 

Our observations strongly suggest that Prorocentrum concavum and Gambierdiscus toxicus are major contributors of toxins to the reef and inshore ecosystems. We believe that these two species produce at least 4 (up to 7) separate toxins which may eventually... 

Lipid-Extracted Toxins from a Dinoflagellate, Gambierdiscus toxicus... 

Crude and three diethyl ether extracted, acetone treated, fractions were isolated from large-scale cultures of Gambierdiscus toxicus. Crude extracts at. 04 mg/ml inhibited the histamine contraction response in smooth muscle of the guinea pig ileum. Three semi-purified fractions at 5 ng/ml, effectively inhibited the guinea pig ileum preparation. Two of these fractions followed Michaelis-Menten kinetics for a competitive inhibition. The third fraction inhibited in a non-reversible manner. This study has established the presence of three lipid extracted toxins in toxicus, outlined a method for their assay in small quantities, and identified at least two of the effects of these toxic extracts in animals. 

Figure 1. Flow diagram for the isolation of toxins Gambierdiscus toxicus.

Bomber, J.W., Tindall, D.R., and Miller, D.M. Genetic variability in toxin potencies among seventeen clones of Gambierdiscus toxicus (Dinophyceae), J. Phycol., 25, 617-625, 1989a. 

Sperr, A.E. and Doucette, G.J. Variation in growth rate and ciguatera toxin production among geographically distinct isolates of Gambierdiscus toxicus, in Harmful and Toxic Algal Blooms, Yasumoto, T., Oshima, Y. and Eukuyo, Y. Eds., l.O.C. of UNESCO, 1996, pp. 309-312. 

McMillan, J.P, PA. Hoffman, and H.R. Granade (1986). Gambierdiscus toxicus from the Caribbean A source of toxins involved in ciguatera. Mar. Fish. Rev. 48, 48-52. 

Holmes, M.J. and R.J. Lewis, Purification and characterisation of large and small maitotoxins from cultured Gambierdiscus toxicus. Nat Toxins, 1994 2(2) 64—72. 

Ciguatoxin (CTX 1) (formula see below). For structural elucidation 0.35 mg of C. (CeoHaeOg, Mr 1111.33) were isolated from 125 kg intestines of the moray Gymnothorax javanicus (primary origin Gambierdiscus toxicus). CTX acts as an agonist of voltage-sensitive sodium channels (VSSC). The lethal dose is 0.35 pg/kg (mouse). Thus, the toxin is about 100 times more potent than tetrodotoxin. 

Dickey RW, Miller DM, Tindall DR (1984) Extraction of a water soluble toxin from a dinoflagellate Gambierdiscus toxicus. Am Chem Soc 23 258-272. 

Miller DM, Dickey RW, Tindall DR (1984) Lipid extracted toxins from a dinoflagellate, Gambierdiscus toxicus. In Seafood Toxins, Ragelis EP (ed). ACS Symposium Sertues 262, pp 241-255. 

Miyahara JT, Kurihara JE, Nakagawa LK, Kobayashi MN, Hokama Y (1987) The similarity of toxin in Ctenochaetus strigosus and cultured Gambierdiscus toxicus. 1st Asia-Pacific Congress on Animal Plant and Microbial, Abstracts, Singapore, p 0080. 

Withers N (1981) Toxin production, nutrition, and distribution of Gambierdiscus toxicus (Hawaiian strain). In Proc. 4th Int Coral Reef Symp No 2. p 449-451. 

Murata, M., Iwashita, T., Yokohama, A., Sasaki, M., and Yasumoto, T. (1992b) Partial structures of maitotoxin, the most potent marine toxin from dinoflagellate Gambierdiscus toxicus. J. Am. Chem. Soc., 114, 6594-6596. 

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