Fish toxins from

The next section, AUelochenUcals for Control of Insects and Other Arumals, discusses insect resistance factors in petunias, geraniums, com, centipede grass, sunflowers, and neem, as well as insecticidal activity of monoterpenoids and fish toxins from mangrove plants. 

HPLC has also been utilized in more complex food chain transfers. It has been known for some time that the toxins can be responsible for fish kills in the Bay of Fundy 18). The vectors for these fish kills are zooplankton that feed on toxic dinoflagellates. In two related studies (79 Sullivan, unpublished), HPLC was utilized to investigate the transport of toxins from dinoflagellates to zooplankton and then to fish. The HPLC method is ideally suited for this since only very small sample sizes (ca. 100,000 dinoflagellate cells) are required. 

Assays of ciguatoxin. Determination of ciguatoxin levels in fish was carried out in many laboratories by mouse assays. Enzyme immunoassay to screen inedible fish has been proposed by Hokama (9). No specific chemical assay has been developed, as information on functional groups suitable for fluorescence labeling is not available. Analyses conducted in the authors laboratory on remnant fish retrieved from patients meals indicated that ciguatoxin content as low level as 1 ppb could cause intoxication in adults. An extremely high sensitivity and a sophisticated pretreatment method will be required for designing a fluorometric determination method for the toxin. 

The best method of preparing individual toxins from the crude venom is by affinity immunochromatography utilizing monoclonal antibody or in one instance, polyclonal antibody (4—6). Monoclonal antibodies to both the fishing and mesentery... 

Venom is secreted from the dorsal, pelvic and anal spines. A review of original papers indicates that many papers have failed to specify from which spine the venom was obtained. Therefore, some publications are meaningless scientifically. Not a single component of fish venoms has been characterized for the amino acid sequence yet. Even the molecular weight of fish toxins is not clear. Deakins and Saunders (25) concluded that the molecular weight of Scorpaena toxin was 150,000, while Schaeffer et al. (26) concluded that it had a molecular weight range of 50,000 to 800,000. 

Fish Products. As explained earlier, it is unlikely that paralytic shellfish toxins have an impact on the utilization of fish products from the point of view of the suitability of fish as food, except perhaps in cases where whole fish are eaten with little processing. Fish simply are unable to accumulate the toxins in their muscle tissues. But the toxins do appear to have an impact on the marketing of fish products, related to consumer wariness of seafood products in general during red tide and PSP incidents. The media blitz surrounding these incidents often leaves consumers unaware of which particular seafood items to be cautious. Consequently, finfish as well as shellfish products have been avoided during these episodes (25). 

Source of Extracted Fish Toxin. Two different extracts of ciguatoxic fish were used in this study. Partially purified ciguatoxin was derived from the liver and viscera of the Pacific moray eel (Gymnothorax Javanicus) and was a side fraction of the... 

Tetrodotoxin. Toxin from ovaries and Experimental poison liver of globe fish. LD50 in mice... 

Latrunculins A (272) and B (273) are two fish toxins first isolated from the Red Sea sponge Latrunculia magnifica (220,221). Two minor toxins named latrunculins C (274) and D (275) were isolated from the same sponge (222). Latrunculin A (272) was isolated from the Pacific nudibranch Chro-modoris elisabethina (223), and latrunculin B (273) was obtained from a nudibranch Glossodoris quadricolor (224) these nudibranchs are known... 

White, A. W., Sensitivity of marine fishes to toxins from the red-tide dinoflagellate Gonyaulax excavata and implications for fish kills, Mar. Biol., 65, 255, 1981. 

Tester, P.A., Turner, J, and Shea, D. 2000. Vectorial transport of toxins from the dinoflagellate Gymnodium breve through copepods to fish. Journal of Plankton Research 22, 47-61. 

In addition to toxins from fungi, food may be contaminated with toxins produced by bacteria, such as botulinum toxin. Produced by the bacterium Clostridium botulinum, it is one of the two most potent toxins known to man, the other being ricin (see pp. 150-1). As little as one-hundred-millionth of a gram (i X 10 g) of the toxin—about 0.00000000035 oz— is lethal to a human. Fortunately the toxin is destroyed by heat, and so cooked food is unlikely to be contaminated (although the bacterial spores are quite resistant). The bacteria grow in the absence of air (they are anaerobic), therefore the foods most likely to be contaminated are those that are bottled or canned and eaten without cooking, for example raw or lightly cooked fish. 

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