Experiments were designed to see whether a dinoflagellate, Diplopsalis sp. nov, found in a toxic sample of detritus collected from a ciguatera-endemic area is the cause of ciguatera.
The dinoflagellate in the detritus was separated from other materials by means of sedimentation and sieving through sieves of various mesh sizes. Bioassay of the dinoflagellaterich samples thus obtained proved that the toxicity of each sample was proportionally related to the number of the dinoflagellate cells in the sample. Subsequent extraction of the dinoflagellate sample followed by fractionation of the extracts with solvents afforded two major toxins; a diethyl ether soluble toxin and an acetone precipitable toxin. The former toxin was judged to be identical, or closely related, to ciguatoxin, a major toxin in ciguatera, on the basis of various column and thin layer chromatographic properties. A close similarity was also observed between the acetone precipitable toxin and maitotoxin, a secondary toxin isolated from ciguateric surgeonfish.
Judging from these results, it was concluded that Diplopsalis sp. nov is very likely to be the cause of ciguatera.
The Japanese Society of Fisheries Science