北黄海慢原甲藻形态结构与腹泻性贝类毒素组成

Morphological and toxicological characterization of DSP producing dinoflagellate,Prorocentrum rhathymum,isolated from the North Yellow Sea,China

慢原甲藻鉴定的报道不仅少见也存在分歧,其产毒特征也因不同地理种而存在差异,形态学和分子生物学应用与毒素分析相结合进行分析的报道更是少见。本研究对采集自温带的中国北黄海海域的疑似慢原甲藻株系,利用光学显微镜(LM)、荧光显微镜(FM)和扫描电子显微镜(SEM),对其形态学进行仔细观察;经核糖体18S rRNA序列分析,建立该株系的系统发生树,判定该藻株与其他藻株的亲缘关系;通过液相色谱质谱联用法(LC-MS/MS)检测该藻株产生毒素的主要成分。观察发现该慢原甲藻长为(33.20±1.25)μm,宽为(24.50±1.39)μm;与墨西哥原甲藻相比,细胞表面分布有整齐排列的刺胞孔,无更小的拟孔。18S rRNA序列分析结果表明此株藻与P.rhathymum(EU287487)和P.tsawwassenense(EF657885)遗传相似性最高,因此判定此藻为慢原甲藻。LC-MS/MS检测发现了其可产生疑似DTX1(Dinophysis toxin 1)的衍生物。本研究将为进一步了解慢原甲藻的地理分布和分类地位以及毒素特征提供参考。

The reports on Prorocentrum rhathymum are not only rare and also divergent,and the toxin production of which are various from place to place. The method combined with morphological,molecular and toxic producing analysis also remains unclear. In this paper,the light microscopy（ LM）,fluorescent microscopy（ FM） and scanning electron microscopy（ SEM） were used for morphological observation of suspected Prorocentrum rhathymum collected from the North Yellow Sea,China; analysis of 18 S rRNA genes were applied for phylogenetic tree to identify the relationship between sampled algae and other species; LC-MS/MS detection method was used for the detection of toxic components produced by sampled P. rhathymum. The results indicated that P. rhathymum isolated from the North Yellow Sea,China was（ 33. 20 ± 1. 25） μm in length and（ 24. 50 ± 1. 39） μm in width,on the plates of which distributing lined tricocyst pores and no poroid pores were observed. The 18 S rRNA sequence analysis showed the sampled algae species had a closer relationship with genetic similar coefficient with P. rhathymum（ EU287487） and P.tsawwassenense（ EF657885）. Taken together,the algae sampled in North Yellow Sea was identified as P. rhathymum. The LC-MS/MS analysis indicated that the sampled P. rhathymum might produce DTX1 derivatives. These results could provide the reference for the research on the geographical distribution,taxonomy and toxin producing characterization of P. rhathymum.