Puffer toxicity

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). 

Other Lethal Agents. There are a number of substances, many found in nature, which are known to be more toxic than nerve agents (6). None has been weaponized. Examples of these toxic natural products include shellfish poison, isolated from toxic clams puffer fish poison, isolated from the viscera of the puffer fish the active principle of curare "heart poisons" of the digitaUs type the active principle of the sea cucumber active principles of snake venom and the protein ricin, obtained from castor beans (See Castor oil). 

Pioneering studies were made to determine the structure of tetrodotoxin 1, one of the most toxic compounds among the low-molecular-weight poisons, found in the ovaries and liver of puffer fish, which is a highly esteemed delicacy in Japan. With a combination of the most versatile instrumental facilities, the complex perhydroquinazoline structure of 1 was established (65T2059) in the early 1960s. 

Pufferfish. Toxic species are members of the order Tetrodontiformes (Plectognathi) and include the sharp-nosed puffers (Canthigaste-ridae). porcupine fish (Diodontidae) as well as the true puffers or fugu (Tetraodontidae). Many human fatalities continue to occur from eating these fish, including an occasional fatality in Florida (cf. 1.9 9 ). The toxin occurs principally in the ovaries9 liver and, in some species, the skin. 

The variability of toxicity within a particular species with respect to individuals, geographic location, and season (1,40). Decrease in toxicity of eggs of pufferfish during development (41) and the lack of toxicity of cultured pufferfish (42,43). Development of toxicity of non-toxic cultured puffers when fed the livers of toxic wild puffers, but failure to develop toxicity when fed pure tetrodotoxin (42). 

Exogenous Origin. The theory that tetrodotoxin arises in the environment and is ingested by these animals is favored by the finding that cultured puffers are non-toxic. It is also favored by the feeding experiments of Matsui (42), in which non-toxic puffers became toxic upon ingesting toxic livers of wild puffers. The... 

A mouse bioassay method is useful for screening of the toxicity of various organisms from affected areas, although this method may not be sufficient for the identification of the toxin. Recently, distribution of tetrodotoxin in the marine ecosystem has expanded from puffer-fishes to some other animals. Rapid and accurate determination of the toxin occurring in those organisms is becoming increasingly important from the public health standpoint. 

Many fish species, over 700 species worldwide, are either directly toxic or upon ingestion are poisonous to humans. A classic example is the toxin produced by the puffer fishes (Sphaeroides spp.) called tetrodotoxin (TTX). Tetrodotoxin is concentrated in the gonads, liver, intestine, and skin, and poisonings occurs most frequently in Japan and other Asian countries where the flesh, considered a delicacy, is eaten as fugu. Death occurs within 5 to 30 minutes and the fatality rate is about 60%. TTX is an inhibitor of the voltage-sensitive Na channel (like saxitoxin) it may also be found in some salamanders and may be bacterial in origin. 

The highly toxic guanidinium alkaloid tetrodotoxin was first isolated from the Japanese puffer fish, Fuga rubipes. In the early 1960s, a guanidinium alkaloid was isolated from eggs of the California newt Taricha torosa and named tarichatoxin (185). It proved identical with tetrodotoxin from puffer fish (186 see Ref. 5 for a historical review). Tetrodotoxin and other guanidinium toxins, namely, chiriquitoxin and the zetekitoxins, have been shown to occur in other amphibians. 

More recent studies have identified the most potent toxin produced by the frog as batrachotoxin (although it is one of about a hundred toxins). This is one of the most toxic substances known—five times more potent than tetrodotoxin, the toxin found in puffer fish (see pp. 252-3)—and a dose of 200 pg would be lethal for a human. Interestingly, tetrodotoxin is also found in the Californian newt. Batrachotoxin is secreted through the skin when the animal is stressed, and so when animals hck or bite the frog they are exposed to the toxin, which causes death by stopping the heart beating. 

The fargefs for natural biological toxins include ion channels and receptors for transmitfers. At least four parts of fhe volfage-gafed sodium charmels are binding sifes for extremely toxic natural products. " Tetrodotoxin (Fig. 30-16), which is found in the puffer fish, certain newts, and venom of fhe blue-ringed octopus, and also the shellfish poison saxitoxin (Fig. 

Tetradotoxin is a potent neurotoxin isoiated from the ovaries and liver of many species of Tetradodontidae, especiaiiy the Japanese fugu (or puffer fish). Saxitoxin is a mussel or clam poison produced by certain marine dinoflagellates, Gonyaulax catenella or G. tamarensis, the consumption of which cause the mussels or clams to become poisonous. These poisonous shellfish were connected to a toxic red tide environmental condition on the coastal region of California in early 1970. Batrachotoxin is a cardiotoxic and neurotoxic steroid isolated originally from the poison dart frog, Phyllobates terribilis. It is a lipid soluble neurotoxin that is at least 10-fold more toxic than tetradotoxin. 

Nunez-Vazquez EJ, Yotsu-Yamashita M, Sierra-Beltran AP, Yasumoto T, Ochoa JL. Toxicities and distribution of tetrodotoxin in the tissues of puffer fish found in the coast of the Baja California Peninsula, Mexico. Toxicon 38 729-734, 2000. 

Tetrodotoxin, from the puffer fish and other members of the order Tetraodontiformes, is a neurotoxin much like saxitoxin in its mechanism of action, toxicity, and physical characteristics. Palytoxin, from the soft coral Palythoa tuberculosa, is extremely toxic and quite stable in impure form, but difficulty of production or harvest from nature reduces the likelihood that an aggressor would use it as an MCBW. The brevetoxins, commonly associated with red tide dinoflagellate blooms, and the blue-green algal toxins like microcystin, a hepatotoxin, have limited toxicity. 

Furthermore, the protocols for how to make puffer safe to eat and how to prevent puffer products made from toxic puffers have been suggested. Finally, the biological significance and neurophysiological role of TTX have been elucidated and TTX may act as an important drug like anesthetic in future. 

Tetrodotoxin (TTX), a puffer toxin named after its order name Tetraodonti-formes by Professor Y. Tahara in 1880, is one of the most potent nonproteinac-eous toxins known, responsible for numerous fish poisonings. This toxin is one of the oldest known natural toxins recorded as early as 2700 BC in Chinese literature, describing the toxicity of puffer, and around 2500 BC in Egyptian history. 

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