Paralytic shellfish toxin

Anabaena Yes Anatoxin-a Anatoxin-a(S) Microcystins Paralytic shellfish toxins... 

Cyanobacterial neurotoxins are small ringed alkaloids and have dramatic effects on various components of vertebrate neurons. They are all water soluble and are synthesized by several cyanobacterial genera (Table 5.1). The most commonly isolated neurotoxins are the paralytic shellfish toxins, although several other potent neurotoxic alkaloids are synthesized by freshwater cyanobacteria (Table 5.1). 

The paralytic shellfish toxins (PSTs Fig. 5.2a) include saxitoxin (STX) as well as STX analogs such as neo-saxitoxin (neo-STX), gonyautoxin (GTX), and the decar-bamoyltoxins (Sivonen and Jones 1999). These molecules are of particular concern in marine systems, where they have been implicated in human deaths following the consumption of contaminated seafood (Van Dolah 2000). The causative agents in those cases are several genera of marine dinoflagellates that are common components of red tides (e.g., Alexandrium sp. Homer et al. 1997 Van Dolah 2000). 

Kotaki, Y., Oshima, Y. and Yasumoto, T., Analysis of paralytic shellfish toxins in marine snails, Bull. Jpn. Soc. Sci. Fish., 47, 943, 1981. 

Raj, U., et al., The occurrence of paralytic shellfish toxins in two species of xanthid crab from Suva barrier reef, Fiji Islands, Toxicon, 21, 4, 547, 1983. 

Glaucous-winged gull Clams Paralytic shellfish toxins Pawlik, 1993 ... 

HALL AND REICHARDT Cryptic Paralytic Shellfish Toxins... 

Despite the uncertainties in HOP for the toxins, there is reason to suspect that their mouse intraperitoneal potencies (MIP), the ri for the standard mouse bioassay system, do not bear a uniform relationship to them. Early pharmacological work ( ) on the paralytic shellfish toxins was conducted with shellfish extracts. 

Paralytic shellfish toxins in the dinoflagellate ProtogonyauZax =Gonyaulax) spp. and bivalves of temperate waters have been the subjects of extensive studies. In contrast, information on the occurrence of these toxins in tropical waters has been scarce. 

In this paper we summarize our recent findings on paralytic shellfish toxins in tropical waters (8-15) with new assignment of a component previously unreported. It includes the confirmation of paralytic shellfish toxins in the dinoflagellate Pyrodinium bahamense war, aompressa and bivalver exposed to the organism (, with structural elucidation of three components (9,1 ). The detailed analyses of the toxin composition of crabs (11-13) and marine snails (13,14) and confirmation of a calcareous red alga Jania sp. as the primary source of the toxins ( 15) are also described. 

Bioassay. Toxicity of the materials was measured by the standard mouse bioassay for paralytic shellfish toxins and expressed by mouse unit (MU) as defined by the method (16). For testing the low toxin levels of algal specimens, extracts were treated with a charcoal column prior to injection into mice. 

Toxins were extracted with 0.1 N HCl or 75% EtOH acidified to pH 2 and treated with successive columns of charcoal, Bio-Gel P-2 and Bio-Rex 70. Toxins separated by the last column were identified by tic and electrophoresis. Relative abundance of each toxin was determined by monitoring the eluate from Bio-Rex 70 column by mouse assay. A fluorometric paralytic shellfish toxin analyzer was applied to samples which were too small to be followed by mouse assay. Toxins separated by the ion exchange column (Hitachi gel 3011C) were continuously aromatized by tei t-butylhydroperoxide and monitored by the fluorometer (1 ). 

OSHIMA ET AL. Paralytic Shellfish Toxins in Tropical Waters... 

The impact of paralytic shellfish toxins on the utilization of shellfish resources is widespread and well recognized. The picture is developing that paralytic shellfish toxins also affect finfish resources. Stated simply, paralytic shellfish toxins cause fish kills. 

Since 1976, when a herring kill was caused by paralytic shellfish toxins in the Bay of Fundy, our laboratory has been investigating the effects of the toxins on fish and the food web routes through which the toxins reach fish. 

Reports implicating paralytic shellfish toxins in fish kills are summarized in Table I. The first instance in which it was suspected that these toxins were the cause of a fish kill occurred in May 1968... 

In July 1979, mortalities of menhaden (Brevoortia tyrannus) occurred along the southern coast of Maine during a . excavata bloom ( ). Paralytic shellfish toxins were measured in the guts of these fish, up to 185 Jig per 100 g of viscera. Since phytoplankton constitute a major part of the diet of menhaden ( ), the toxins were probably acquired directly from ingestion of the toxic dinoflagellates. 

Fish kills have been reported for the Indo-Pacific region in association with blooms of another dinoflagellate, Pyrodinium bahamense ( ), which has since been confirmed to contain paralytic shellfish toxins (9 ). Whether the toxins were involved in the kills apparently remains unknown. 

Using paralytic shellfish toxins extracted from mass cultures of Bay of Fundy excavata, we have found the symptoms of poisoning and the time course of their appearance to be similar in Atlantic herring, American pollock, winter flounder, Atlantic salmon, and cod (10). 

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