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

用Bligh-Dyer法、硅胶-薄层色谱和反相柱(L柱)相结合的方法，从两种水母的自溶物中分离出对有害鞭毛藻赤潮异弯藻有杀藻作用的物质。从层析行为和LC-MS分析结果可知，雷氏梭子藻的5种杀藻剂分别为二十二碳六酸(M：W=328，22：6)、二十碳五烯酸(M.W=302，20：5)、二十七烷酸(M.W=268，17：1)、三酰甘油(相对分子质量为344)和346(R1+R2+R3的C数分别为13和6个双键)和346(R1+R2+R3的C数分别为13和6个双键)和346(R1+R2+R3的C数分别为13和6)。例如牡蛎和珍珠母。本试验是为了了解水母的杀藻剂(顺-5，8，11，14，17-二十碳五烷酸)是否能杀死牡蛎和珍珠母体内的有毒鞭毛细胞。在海水中加入海蜇自溶物(终浓度为5%v/v)浸泡后，两种贝类的环状螺旋藻细胞数在8小时后降至初始数的10~40%，13小时后降至初始数的5%，实验期间未见有贝类死亡。目前的处理方法有望用于减少受有毒鞭毛虫感染的贝类的繁殖。

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.