Toxic starfish

Trumpet shells can become highly intoxicated by ingesting toxic starfish (Noguchi et al, 1982). 

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). 

Four antimicrobial peptides, discodermins A-D (383-386), isolated from the Japanese sponge Discodermia kiiensis also show inhibitory activity on the development of starfish embryos (317,318). Three ichthyo-toxic peptides, pardaxins P-1 through P-3 (387-389), were isolated from... 

In museum collections, most invertebrates will be encountered as natural history specimens, which are divided into dry and wet-preserved. Those animals having a shell or tough exoskeleton, like starfish, shelled mollusks, and lobsters, may be dried after death. The tissue may be removed, but it is often left inside the shell or carapace to shrivel and dry. Wet-preserved specimens are usually fixed in a solution of formalin or some other preservative to prevent the tissues from deteriorating quickly after death. After a brief period, the specimen is usually removed from the toxic fixing solution, rinsed, and placed in a storage solution of 70% ethanol (alcohol) mixed with water. 

Asterosaponins are usually considered to be responsible for the general toxicity of starfish. However, this investigation showed that sterols and another class of minor chemical components, such as glycosides of polyhydroxysteroids also play an important role in the general toxicity. 

A new type of saponin was discovered as toxic substances in starfishes of the genus Echinaster. The stmcture of steroidal cyclic glycosides, sepositoside A (76) from the Mediterranean starfish Echinaster sepositus [100] was determined. Three major saponins in the same starfish were isolated, and their structures were found to have 22,23-epoxide groups in the side chain [101]. 

The toxicity of starfishes may be derived from the saponins. The biological activities of these compounds were reported, including haemolytic properties, and antitumour [104] and antibacterial activities [105]. Inhibition activities for influenza virus multiplication, and anti-inflammatory activity towards contraction of the rat phrenic nerve diaphragm preparation, were also reported [106]. Saponins are chemical defence agents in starfishes, and they also induce escape reactions in bivalve molluscs [107]. It is of interest to note that the sperm agglutination substance in the egg jelly of starfish is similar to asterosaponin A [108]. 

Astropecten latespinosus and Astropecten scoparius were also added to the list ofTTX-bearingechinoderms (Maruyamaet a/., 1984,1985 Miyazawa et a/., 1985) from the results of toxicity examination of starfish collected from all over Japan. In the mouse assay, A. latespinosus and A. scoparius showed the toxicity scores of 13 and 5.7 MU/g, respectively. These findings made sure of TTX intoxication mechanism in gastropods to come from their food chain. Afterward, TTX study gave a clue to be expanded in many aspects. In 1985, TTX was also reported from starfish A. polyacanthus and A. scoparius from Seto Inland Sea, Japan, with the highest toxicity scores of 520 and 46 MU/g, respectively (Miyazawa et al., 1985). 

In regard with transmission of TTX through the food web, TTX in puffers seems to come directly from their food, such as toxic gastropods, flatworm, and starfish. TTX commonly accumulates in the eggs of puffers. 

Presently, distribution of TTX is known in only a limited number of organisms (Table II). Toxicity data on TTX-bearing animals collected show more or less toxicity in them irrespective of local and individual variations of toxicity. All of them are found to be carnivorous. TTX in them seems to come directly from their food, such as in puffers, toxic gastropods, flatworms, and starfish, and is accumulated in species-specific organ(s). 

The starfish accumulated a lot of TTX from small toxic gastropods (Lin and Hwang, 2001). 

Echinodcwm saponbis. Asteroids (starfish) and ho-lothuroids (sea cucumbers) secrete saponins for defense. The E. s. are responsible for the general toxicity of these creatures, they have cytotoxic, hemolytic, ichthyotoxic, and microbicidal activities. As yet E. s. have not been detected in sea urchins and feather stars. Starfish contain only steroid saponins while sea ur-... 

More than 10 hypotheses with different degrees of analysis were put forward to reveal the causes of the EC in the White Sea in 1990. We will discuss only two. Both of them were based on the findings of the State Commission having investigated this accident The death of starfish was caused by an unknown toxicant . However, due to the events of 1990-1991 no official conclusion of the Commission ever appeared. 

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