Paralytic toxins newly isolated from the red tide of Cochlodinium type'78 Yatsushiro

Research Project

Project/Area Number	60560222
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Fisheries chemistry
Research Institution	Kagoshima University
Principal Investigator	ONOUE Yoshio Kagoshima University, 水産学部, 助教授 (10160920)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	Cochlodinium / Toxic plankton / Red tide / Paralytic toxins / Neurotoxins / Hemolysin / Hemagglutinin / 凝集素
Research Abstract	Two unique toxins were isolated from the supernatant collected by continuous centrifugation from the red tide of Cochlodinium type '78 Yatsushiro. The structures of two of these were deduced to be a zinc complex of carbamoyl-N-sulfo-11 <alpha> -hydroxyneosaxitoxin sulfate (1) or its 11 <beta> epimer (2), based on electrophoresis, TLC, <^1H^-> NMR, FAB-Mass, fluorescent X-ray and conversion experiments. 1 revealed little toxicity on intraperitoneal injection into mice. 2 showed a specific toxicity of 50-80 mouse units/mg. The 50% lethal concentrations of 1 and 2 on juvenile red seabream were 10-15 and 1-5 mg%, respectively. On mild acid hydrolysis, 1 and 2 were converted to highly toxic compounds, i.e., 11 <alpha> -hydroxyneosaxitoxin sulfate and its 11 <beta> epimer. On the other hand, three high-molecular toxic fractions (neurotoxin, hemolysin and hemagglutinin) were also separated from the algal cells through the treatments such as organic solvent fractionation, aqueous phenol extract and dialysis. These three toxic fractions caused abnormality (e.g., edema) in the secondary gill lamella of juvenile red seabream at a concentration of 0.01% in seawater (temp. 26-27゜C, DO 6-8 ppm). The opercular lesion was most conspicuous on exposure to the neurotoxin fraction. The hemolytic number of hemolysin fraction on sheep red blood cell was estimated to be 600 and the hemagglutinative titre of hemagglutinin fraction to be 6200 on the same blood cell. Further purifications and refined studies of these three fractions are now in progress in this laboratory.