Dinoflagellate, Gonyaulax catenella

Nitrogen-containing compounds which have been isolated during the past year from sources other than plants and therefore not truly defined as alkaloids are not reviewed. These are saxitoxin (65) from the dinoflagellate Gonyaulax catenella, and leucogenenol (66), a metabolite of Penicillium gilmaniiP ... 

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. 

The paralytic poison produced by the dinoflagellate Gonyaulax catenella in axenic culture has been isolated in pure form by Schantz et al. (1966). A study of its chemical, physical, and biological properties established that it is identical in chemical structure to saxitoxin, the poison isolated from toxic Alaska butter clams (Saxidomas giganteus) and to the poison isolated from toxic California sea mussels Mytilus californiaus). Infrared spectra were given for G. catenella poison and the mussel poison. 

Saxitoxin is an alkaloid of nonplant origin. It is the neurotoxic constituent of dinoflagel-lates (Gonyaulax catenella and G. excavata) the so-called red tide found along the U.S. coast. Shellfish, clams, and scallops consume this and become extremely poisonous for human consumption. 

The mouse bioassay (MBA) was developed 70 years ago by Sommer and Meyer as part of their pioneering work that related the dinoflagellate Alexandrium catenella (Gonyaulax) as a causative agent of PSP (see Wekell et al ). At the time, the identity of the paralyzing toxic compounds was not known and the MBA remained for several years as a field test to help health officials manage toxic outbreaks in Alaska and British Columbia.Only after a purified saxitoxin dihydrochloride was made available in 1950 was it possible to calibrate the assay, and the AOAC accepted the new version of the MBA as an official method. Reasons for the sustained application of the MBA lie in its simplicity of application, relatively low cost, and availability of test protocols to calibrate mice strains to compare operator performance and to perform repeatability and reproducibility studies (National Shellfish Sanitation Program, USA ). 

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