ISOLATION OF ALGICIDAL SUBSTANCES IN JELLY-FISH AND THEIR UTILITY FOR REDUCTION OF RED-TIDES

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12660192
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Fisheries chemistry
• Research Institution: NIHON UNIVERSITY
• Principal Investigator: HIROMI Juro NIHON UNIVERSITY, PROFESSOR, 生物資源科学部, 教授 (30112923)
• Co-Investigator(Kenkyū-buntansha): UCHIDA Naoyuki NIHON UNIVERSITY, PROFESSOR, 生物資源科学部, 教授 (80151885)
• Project Period (FY): 2000 – 2001
• Keywords: JELLYFISH / AUTOLYSATE / ALGICIDES / POLYENOICFATTY ACIDS / Heterosigma akashiwo / Heterocapsa circularisquama / PEARL OYSTER / COLLAPSE OFRED-TIDES

Research Abstract

Algicidal substances to a harmful flagellate, Heterosigma akashiwo, in the autolysates of two species of jellyfish, Carybdea rastoni and Chrysaora melanester, were isolated by sequential procedures consisting of Bligh-Dyer's method, silica gel-TLC, and HPLC on a gel filtration column (Superdex peptide HR10/30) and on reverse phase column (L-column, ODS). Judging from the chromatographic behavior and LC-MS analysis of the isolated substances, it was suggested that five kinds of algicides from C. rastoni were Docosahexanoic acid (M : W=328, 22 : 6), Eicosapentaenoic acid (M.W=302, 20 : 5), Heptadecamonoenoic acid (M.W=268, 17 : 1), Triacylglycerols with M.W of 344 (C number of R1+R2+R3 was 13 and 7 of double bond) and 346 (C number of R1+R2+R3 was 13 and 6 of double bond), and that an algicide from C. melanaster was Tetradecsaheptaenoic acid (M.W=227, 15 : 7).
A toxic flagellate Heterocapsa circularisquama is known to kill shellfish, such as oyster and a mother-of-pearl. The test was conducted to know whether the algicide (cis-5, 8, 11, 14, 17-icosapentanoic acid) of the jellyfish Aurelia aurita can kill toxic flagellate cells within oyster and a mother-of-pearl. Number of cells of H. circularisquama in the two shellfish species soaked in seawater added with autolysate of the jellyfish (final concentration ; 5 % v/v) decreased to 10-40 % of the initial number after 8 hours and to 5 % of the initial after 13 hours, without killing no shellfish during experiments. The present treatment is expected to utilize for reducing propagation of shellfishes infected with toxic flagellates.