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

在凝胶过滤柱（Superdex peptide HR10/30）和反相柱（L-column， ODS）上，采用blight - dyer法、硅胶- tlc法和高效液相色谱法分离了两种水母（Carybdea rastoni和Chrysaora melanester）自溶物中对有害鞭毛虫（Heterosigma akashiwo）的杀藻物质。从分离物质的色谱行为和LC-MS分析中，推测出五种杀藻剂分别为：二十二碳己酸（M: W=328, 22: 6）、二十碳五烯酸（M: W=302, 20: 5）、十六碳五烯酸（M: W=268, 17）、六碳五烯酸（M: W=268, 17）。1)、M.W分别为344 （R1+R2+R3的C数分别为13和7个双键）和346 （R1+R2+R3的C数分别为13和6个双键）的三酰基甘油（M.W= 227,15: 7）。众所周知，一种有毒的鞭毛虫会杀死贝类，如牡蛎和珍珠母。本实验旨在了解水母的杀藻剂（顺式- 5,8,11,14,17 -二十碳五酸）是否能杀死牡蛎和珍珠母体内的有毒鞭毛细胞。在加入海蜇自解液（终浓度：5% v/v）的海水中浸泡8小时后，两种贝类的圆纹圆孔螺旋体细胞数下降到初始数量的10- 40%，13小时后下降到初始数量的5%，实验期间没有杀死任何贝类。本方法有望用于减少有毒鞭毛虫感染贝类的繁殖。

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.