ACT toxins

BgK K+ channel-acting toxin from sea anemone Bunodosoma granulifera C (Cys) cysteine (reduced form) or half-cystine residue (oxidized form)... 

HmK K+ channel-acting toxin from spider Heteractis magnifica... 

ShK channel-acting toxin from sea anemone Stichodactyia heiianthus... 

The results of TLC indicated that concavum produced at least three and possibly as many as five separate toxins (Table V). The three relatively distinct toxic components were designated PC-1, PC-3, and PC-5. Results from TLC did not clearly distinguish PC-2 or PC-4 from PC-5. However, mouse bloassay of these fractions (from preparative TLC) revealed that PC-4 was a fast-acting toxin in contrast to the slow-acting PC-2 and PC-5. Of course, the variation in results of the mouse bioassays could have been a consequence of different amounts and levels of purity of the respective fractions. Regardless, preliminary results from TLC and bioassay suggest that PC-2 may be the same as PC-5, the former being a water soluble carryover in the initial ether fraction. 

The fast-acting WSAF from concavum contained two toxic components (PC-3 and PC-4). Separate bloassay of these fractions showed both to cause fast death and other similar symptoms. At present, we can not speculate on relationships between the two or with fast-acting toxins previously identified from other marine organisms. 

In addition to those host nonselective toxins, Altemaria pathogens produce a number of host-selective toxins such as AK-toxin, AF-toxin, and ACT-toxin.298 9,10-Epoxy-8-hydroxy-9-methyldecatrienoic acid, the common backbone of these toxins, was biosynthesized via the polyketide pathway. Genetic approach has allowed the identification of a gene cluster for AF-toxin biosynthesis.299... 

Prorocentrolides and Spiro-prorocentrimine Fast-Acting Toxins with Unknown Molecular Targets... 

Hu, T, deFreitas, A.S., Curtis, J.M., Oshima, Y., Walter, J.A. and Wright, J.L., 1996h. Isolation and structure of prorocen-trolide B, a fast-acting toxin from ProrocenfrMm maculosum. J Nat Prod 59, 1010-1014. 

Wright, J.L.C., Curtis, J.M., Hu, X, and Walter, JA. 1997. The spirolides and prorocentrolide B new additions to a rapidly growing group of fast-acting toxins with a common pharmacophore. 8th Int Conf on Harmful Algae, Abstract p. 215. 

Class Index C22 heart irregularities and low blood rapid acting toxin that causes venom. 

In the early 1990s, routine bioassays detected the presence of a fast-acting toxin in extracts of shellfish from sites along the southeastern coast of Nova Scotia, Canada [11]. Two new toxins of the cyclic imine group, named spirolide B and spirolide D, were isolated from the viscera of scallops (Placopecten magellanicus) and mussels (M. edulis) and their structures determined [12]. Subsequently, spirolides A, C, E, and F were described, along with 13-desmethyl spirolide C [13,14]. 

Hu T. et al. Isolation and structure of prorocentrolide B, a fast-acting toxin from Prorocentrum macu-losum, J. Nat. Prod. 59, 1010, 1996. 

Pettier, I. et al., Identification of slow- and fast-acting toxins in a highly ciguatoxic barracuda (Sphymena barracuda) by HPLC/MS and radiolabelled ligand binding, Toxicon, 42, 663, 2003. 

Also observe for late-onset noncardiogenic pulmonary edema resulting from slower-acting toxins, which may take several hours to appear. Early signs and symptoms include dyspnea, hypoxemia, and tachypnea (see p 213). 

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