Abstract
Toxin compositions in xanthid crabs Zosimus aeneus and Atergatis floridus were examined. Three specimens of each were collected on reefs of Ishigaki Island, Okinawa Prefecture, and were dissected into 6 parts; muscle of appendages, muscle of cephalothorax, skeleton of appendages, skeleton of cephalothorax, viscera, and gills. Toxicity of each tissue was determined by mouse bioassay and toxin compositions by high performance liquid chromatography (HPLC) with fluorometric detection. In both crabs, muscle of appendages gave the highest toxicities (1, 100 5, 900 MU/g)among the 6 tissues, and those of muscle of cephalothorax and gills were less than one tenth of it. In Z. aeneus, relative abun-dances (mole%) of carbamoyl-N-hydroxyneosaxitoxin (hyneoSTX) and neosaxitoxin (neoSTX) were rather high, and 10_??_15% of gonyautoxins (GTXs) were contained in addition to similar amounts of carbamoyl-N-hydroxysaxitoxin (hySTX), decarbamoylsaxitoxin (dcSTX), and saxitoxin (STX) irrespective of tissues except for gills. A. floridus possessed STX predominantly over the other STXs with no detectable amount of GTXs. In both crabs, gills had a somewhat different toxin profile from the other tissues with higher neoSTX and STX but lower hyneoSTX and hySTX. A good correlation was observed between the toxicities calculated from the results of HPLC analyses andthose from mouse bioassay.
