OCCURRENCE OF TETRODOTOXIN IN THE GASTROPODS RAPANA-RAPIFORMIS AND R VENOSA-VENOSA

Paralytic toxicity was detected in four of 17 specimens and six of 28 specimens of the gastropods Rapana rapiformis and R. venosa venosa, respectively, collected from Chiching (Kaohsiung City) and Nanfangao (Ilan County), Taiwan, in 1988 and 1989. The highest toxicities, calculated as tetrodotoxin (TTX) content, were 140 and 13 mouse units (MU) g-1 digestive gland in R. rapiformis and R. venosa venosa, respectively. The toxins obtained from each species were purified by ultrafiltration and Bio-Gel P-2 column chromatography. The toxin's specific toxicities (as TTX) were 56 MU mg-1 (R. rapiformis) and 52 MU mg-1 (R. venosa venosa). Results of analyses by thin-layer chromatography, cellulose acetate membrane electrophoresis and high-performance liquid chromatography showed that TTX and anhydrotetrodotoxin were responsible for the toxicity. The alkali hydrolysate of each toxin showed maximum absorption at ca. 274 nm, which is the unique absorption for the C-9-base of TTX and its related substances (such as anhydrotetrodotoxin, 4-epitetrodotoxin, etc.). Here, we report for the first time the occurrence of TTX in the gastropods R. rapiformis and R. venosa venosa.