Transformation of gonyautoxins in the xanthid crab Atergatis floridus

A mixture of gonyautoxins 2 and 3 (GTX sub(2,3)) in 3% NaCl solution was injected into the right chela of live specimens of the xanthid crab Atergatis floridus which were maintained in an aquarium at 27 degree C. The specimens were then examined for the contents of paralytic shellfish toxins in the chela and viscera 0.5-48h after injection by high performance liquid chromatography (HPLC) equipped with a fluorometric detector. It was shown that most of the GTX sub(2,3) administered were transported from the chela to viscera within 12 h after injection, where they were converted into saxitoxin(STX). A portion of STX in the viscera seemed to return to the chela thereafter. On the other hand, the same species of crab kept in the aquarium was fed on a feed containing a mixture of gonyautoxins 1, 2, 3, and 4 (GTX sub(1-4)) once a day for 3-12 days. GTX sub(1-4) were hardly detectable in the chela and viscera of toxin-fed crab specimens, whereas these tissues accumulated significant amounts of neosaxitoxin and STX. The accumulation of toxins during the feeding period was calculated to be 20-30%.