中国东南海域拟菱形藻属的新记录种和产毒种

拟菱形藻属（Pseudo-nitzschia）物种是一类备受关注的海洋有毒有害硅藻，我国相关研究仍然不足，已报道的物种多样性偏低，产毒物种也较少。为了解我国海域拟菱形藻属的物种多样性，阐述产毒物种信息，在我国东南海域建立了8个拟菱形藻单克隆培养株系，结合形态学和分子系统学数据，鉴定到2个物种:环孔拟菱形藻（Ps.circumpora C.H.Lim，C.P.Leaw&P.T.Lim）和多列拟菱形藻Ps.multiseries（Hasle） Hasle]，其中环孔拟菱形藻是我国的新记录种。利用高效液相色谱-质谱联用法检测了藻株的多莫酸（domoic acid，DA）特征，在5个多列拟菱形藻株系中检测到DA，单细胞产毒水平为1.01~96.11 fg。此外，利用卤虫（Artemia salina L.）和强额拟哲水蚤（Paracalanus crassirostris Dahl）对多列拟菱形藻的产毒株系（MC4177）进行诱导，发现能够提高其单细胞产毒水平，提高幅度在26~55倍。

New record and toxic species of the genus Pseudo-nitzschia from southeastern China waters

The diatom genus Pseudo-nitzschia Peragallo is a kind of harmful bloom microalgae. But the relative studies are still insufficient in China, and low species diversity and few toxic species have been recorded. To explore the diversity and verify the toxicity, 8 monoclonal strains were established from southeastern China waters. Morphology was observed under light and transmission electron microscopy, and the sequences of ribosomal transcribed spacer region were analyzed to build phylogenetic relationships. Combined morphology and molecular data, two Pseudo-nitzschia taxa were identified, i.e., Ps. circumpora C. H. Lim, C. P. Leaw & P. T. Lim and Ps. multiseries (Hasle) Hasle, with the former as a new record for China. Using liquid chromatography tandem mass spectrometry (LC-MS/MS), domoic acid (DA) was detected from 5 Ps. multiseries strains, with DA concentrations around 1.01-96.11 fg/cell. Meanwhile, a toxic Ps. multiseries strain (MC4177) was selected and induced by mix-culture with Artemia salina L. and Paracalanus crassirostris Dahl, respectively. The result showed that DA concentration increased greatly, about 26-55 times after induction.