Tetrodotoxin bacteria

Saxitoxin (STX) is a toxin which is found in marine microorganisms. It is most likely synthesized by bacteria which live in symbiosis with dinoflagellates, a component of phytoplankton. Through the marine food chain, it can lead to poisoning of humans. The mechanism of toxicity of saxitoxin is vety similar to that of tetrodotoxin. Saxitoxin binds from the outside of the membrane to various forms of voltage-sensitive Na+channels and blocks the channel in an activation state-independent manner. 

Tetrodotoxin (TTX) is a toxin derived from bacteria which is concentrated in the gonads and liver of certain pufferfishes (fugu). Similar to saxitoxin, tetrodotoxin is a very potent blocker of most voltage-sensitive Na+ channels. 

Tetrodotoxin (TTX) and saxitoxin (STX) are potent sodium channel blockers that are found in phylogenetically diverse species of marine life. The wide distribution of TTX and STX has resulted in speculation that bacteria are the source of these toxins. Recently, investigators have reported isolation of marine bacteria, including Vibrio Alteromonas, Plesiomonas, and Pseudomonas species, that produce TTX and STX. This chapter details the methods and results of research to define bacterial sources of TTX and STX. 

The tetrodotoxins (TTXs) and saxitoxins (STXs) have in common the ability to block sodium channels of excitable membranes (1—5), Saxitoxin and tetrodotoxin are some of the most potent non-proteinaceous neurotoxins known and are responsible for significant human morbidity and mortality (6, 7). Although for many years the biosynthetic origin(s) of TTXs and STXs has not been identified, recent evidence indicates that bacteria may be a source. 

Hwang DF, Arakawa O, Saito T, Noguchi T, Simidu U, Tsukamoto K, Shida Y, Hashimoto K. (1988) Tetrodotoxin-producing bacteria from the blue-ringed octopus Octopus Maculosus. Marine Biology 100 327-332. 

Carroll S, McEvoy EG Gibson R. (2003) The production of tetrodotoxin-like substances by nemertean worms in conjunction with bacteria. J Exp Mar Biol Ecol 288 51-63. 

Do, H. K., Kogure, K., and Simidu, U., Identification of deep-sea sediment bacteria which produce tetrodotoxin, Appl. Environ. Microbiol., 56, 1162, 1990. 

Tetrodotoxin, however, has been isolated from the Californian newts Taricha torosa, Taricha rivularis, and Taricha granulosa it has formerly been called tarichatoxin but was later found to be identical with tetrodotoxin from Tetraodontidae. We now know that tetrodotoxin is a bacterial toxin (ref. 29) but we have no idea about this kind of symbiosis between bacteria and amphibia. It certainly does not act as a fungicide or bactericide (ref. 30) but it might act as a repellent against predators of the animals themselves or of their egg clusters as has been observed in Tetrodotoxin containing fish. 

Hwang, D.F., Arakawa, O., Saito, T., Noguchi, T., Simidu, U., Tsukamoto, K., Shida, Y., and Hashimoto, K. 1989. Tetrodotoxin-producing bacteria from the blue-ringed octopus. Octopus maculosus. Mar. Biol 100, 327-332. 

Matsui, T., Taketsugu, S., Sato, EL, Yamamori, K., Kodama, K., Eshi, A., EEirose, H., and Shimizu, C. 1990. Toxification of cultured puffer fish by the administration of tetrodotoxin producing bacteria. Nippon Suisan Gakkaishi 56, 705. 

Quinazoline alkaloids a group of about 30 alkaloids, which occur in higher plants (in families taxono-mically very distant from one another), animals and bacteria. They are derived biosyntfaetically from an-thranilic add. The simplest representative of the Q.a. is Glomerine (see) which is a very rare animal Q.a. Of the plant Q.a., Febiifugine (see) has some significance. In the wide sense, tetrodotoxin fi-om the puffer... 

Tetrodotoxin Bacteria Alkaloid (guanidine) Inhibitor of sodium channels, voltage-dependent 385/1 mg... 

Many chaetognaths host bacteria of the genus Vibrio, which confer on them toxicity due to the presence of tetrodotoxin (Thuesen and Kogure, 1989). Bioluminescence has also been reported (Haddock and Case, 1994). The chitin of the hooks of species of Sagitta is a-chitin, the most common form among arthropods and fungi (Bone, Ryan, and Pulsford, 1983 Saito et al, 1995). 

Wu, Z., Yang, Y., Xie, L., Xia, G., Hu, J., Wang, S., and Zhang, R. (2005a) Toxicity and distribution of tetrodotoxin-producing bacteria in puffer fish Fugu rubripes collected from the Bohai Sea of China. Toxicon, 46, 471—476. 

Cheng, C.A., Hwang, D.F., Tsai, Y.H., Chen, H.C., Jeng, S.S., Noguchi, T, Ohwada, H., and Hasimoto, K. (1995) Microflora and tetrodotoxin-producing bacteria in a gastropod, Niotha clathrata. Food Chem. Toxicol., 33, 929-934. 

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