Coelenterate toxins

Uemura, D., Ueda, K., Hirata, Y., Katayama, C., and Tanaka, J. 1980a. Structural studies on palytoxin, a potent coelenterate toxin. Tetrahedron Letters 21(50) 4857- 4860. 

Coelenterate toxins found in jellyfish and sea anemones bind to both sodium and potassium channels (Messerli, 2006). Coelenterates represent the earliest extant creature with a neuromuscular system. Toxins from the sea anemone are the best characterized cnidarian toxins in terms of mechanism of action, and more than 50 different toxins that target sodium VGICs have thus far been isolated or cloned (Honma, 2006). Each of these toxins can serve as a probe of sodium VGIC structure and function, and provide selectivity for sodium-dependent mechanisms in cardiac and neuronal tissues, to include autonomic nerves that mediate gastrointestinal symptoms in a variety of disease states. 

Uemura, D., K. Ueda, Y. Hirata, C. Katayama, and J. Tanaka Structural Studies on Palytoxin, a Potent Coelenterate Toxin. Tetrahedron Lett. 21, 4857 (1980). 

Meinardi, E., Florin-Christensen, M., Paratcha, G., Azcurra, (.M., and Florin-Christensen, J. (1995) The molecular basis of the self/non-self selectivity of a coelenterate toxin. Biochem. Biophys. Res. Commun., 216, 348-354. 

Coelenterates and Echinoderms. In the phylla Coelenterata and Echinodermata approximately 90 species have been investigated for toxicity (see Tables II and IH). Only 20 or so have been extensively studied (e.g., sea anemones, sea cucumber, and jellyfish). Even so, while relatively complete studies have been made on isolation, characterization, and elucidation of mechanisms of action, in no one species have all of the toxins present been identified. Thousands of species have not been subjected to even the most cursory examination. 

Coelenterates and Echinoderms. Coelenterate and echinoderm toxins range from small molecular weight amines, to sterols, to large complex carbohydrate chains, to proteins of over 100,000 daltons. Molecular size sometimes reflects taxonomy, e.g., sea anemones (Actiniaria) all possess toxic polypeptides varying in size from 3,000 to 10,000 daltons while jellyfish contain toxic proteins (ca. 100,000 daltons). Carotenoids have been isolated from Asterias species (starfish), Echinoidea (sea urchins), and Anthozoans such as Actiniaria (sea anemones) and the corals. These are sometimes complexed with sterols (J5). 

The actions of proteins isolated from sea anemones, or other coelenterates, involve mechanisms different from those described for saponins. Thus, hemolysins from sea anemone R macrodactylus are capable of forming ion channels directly in membranes (98). The basic protein from S. helianthus also forms channels in black-lipid membranes. These channels are permeable to cations and show rectification (99). This ability of S. helianthus toxin III to form channels depends upon the nature of the host lipid membrane (100). Cytolysin S. helianthus binds to sphingomyelin and this substance may well serve as the binding site in cell membranes (101-106). 

Many of the toxins obtained from coelenterates and echinoderms, because of their hemolytic or cytotoxic actions, are assumed to have a general disruptive action on cell membranes. However, since many of these toxins are capable of forming pores or channels in the plasma membrane of cells, their cytolytic actions may be a result of this highly selective action. On the other hand, the saponins from starfish and sea cucumbers have a direct lytic action as a result of their detergent action on the integrity of cells. 

Fire corals are coelenterates belonging to the genus Millepora. On touch, toxins in... 

Coelenterate (cnidarian) toxins are found in venomous jellyfish and sea anemones. They produce not only severe pain, but also contact dermatitis that may include hemolysis and scarification. Some jellyfish envenomations are fatal, to include stings by both large (Chironex fleckeri) and small (Carukia barnesi) Australian box jellyfish (Watters, 2006a). Anaphylaxis may occur with species that have less toxic venoms. Prevention from envenomation by those who enter the marine environment is therefore clinically important. 

Moore RE, Scheurer PJ (1971) Palytoxin a new marine toxin from a coelenterate. Science 172 495... 

The phylum Coelenterata is subdivided into the classes Hydrozoa, Cubozoa, Scyphozoa, and Anthozoa. The latter class is subdivided into Hexa- and Octocorallia. Many coelenterates produce toxic or other biologically active metabolites 235). For example toxins are used by jellyfish and sea anemones for defence or in order to capture prey. 

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