Molecular ecology for the purpose of terminating toxic dinoflagellate by gene analysis of some enzymes relating to PSP toxin synethesis.

本文研究了钩鞭毛藻亚历山大菌（Alexandrium catenella）和塔玛兰藻（A.tamarense）麻痹性贝类中毒（PSP）毒素组成的稳定性以及产生PSP毒素的遗传系统。利用克隆培养，测定了许多群体和f_1后代不同生长阶段的细胞材料中的毒素成分。在所使用的所有分离株中，毒素组成的摩尔百分比在任何生长阶段都没有显着变化。对来自8个不同水域的这两个物种的70多个菌株的毒素组成分析表明，存在来自遥远地方的种间和种内土著种群。测定了具有不同毒素谱的藻系杂交的许多f_1后代的毒素组成。毒素组成的遗传主要以1:1孟德尔模式遗传，性取向（交配类型）与毒素遗传无关。这些数据有力地表明，A.catenella和A.tamarense的PSP毒素组成是稳定的，毒素谱的孟德尔遗传发生在这两种异thallic鞭毛藻中。此外，我们还尝试分离出了一些在tamarense和G.catenatum中与PSP生物合成有关的酶。首先，通过多个色谱柱纯化了藤中STX或GTX2+3向GTX5或C1+2的n -亚砜转移酶。该酶由两个相同的亚基（63kDa）组成，在pH6.0和25偶联温度下具有最佳活性。Mg^<2+>刺激其活性，而PAPS类似物抑制其活性。其次，部分纯化了将11- α， β -羟基STX转化为GTX2+3的o -磺基转移酶。这些酶的DNA序列将在来年进行分析。

We investigated the stability of paralytic shellfish poisoning (PSP) toxin composition in the dinoflagellate Alexandrium catenella and A.tamarense, and the genetic system producing it. Using clonal axnic cultures, toxin compositions were determined in cell material from different growth phases of many populations and F_1progenies. In all isolates used, the mole percentage of toxin composition did not significantly change in any growth phase. Toxin composition analysis of over 70 strains of both species from 8 different waters indicate the occurrence of inter-and intra-specific indigenous populations from distant localities. Toxin compositions of many F_1progenies from crosses between algal strains having different toxin profiles were determined. Toxin compositions were inherited mostly in a 1 : 1 Mendelian pattern and sexuality (mating type) was not associated with toxin inheritance. These data strongly suggest that PSP toxin compositions of A.catenella and A.tamarense are stable and that Mendelian inheritance of toxin profiles occurs in both these heterothallic dinoflagellates.Furthermore we have tried to isolate some enzymes relating to PSP biosynthesis in A.tamarense and G.catenatum. Firstly, N-sulfotransferase from STX or GTX2+3 to GTX5 or C1+2 was purified from G.catenatum through several columns. The enzyme consisted of two identical subunits (63kDa) and was optmally active at pH6.0 and 25ﾟC.The activity was stimulated by Mg^<2+> and inhibited by PAPS analogue. Secondly, O-sulfotransferase which converted 11-alpha, beta -hydroxy STX into GTX2+3 was partially purified. DNA sequence of these enzymes will be analyzed in the coming year.