Rasmussen Silas Anselm, Meier Sebastian, Andersen Nikolaj Gedsted, Blossom Hannah Eva, Duus Jens Øllgaard, Nielsen Kristian Fog, Hansen Per Juel, Larsen Thomas Ostenfeld
Department of Biotechnology and Biomedicine, Technical University of Denmark , Søltofts Plads 221, 2800 Kgs. Lyngby, Denmark.
Department of Chemistry, Technical University of Denmark , Kemitorvet 207, 2800 Kgs. Lyngby, Denmark.
J Nat Prod. 2016 Sep 23;79(9):2250-6. doi: 10.1021/acs.jnatprod.6b00345. Epub 2016 Aug 23.
Blooms of the microalga Prymnesium parvum cause devastating fish kills worldwide, which are suspected to be caused by the supersized ladder-frame polyether toxins prymnesin-1 and -2. These toxins have, however, only been detected from P. parvum in rare cases since they were originally described two decades ago. Here, we report the isolation and characterization of a novel B-type prymnesin, based on extensive analysis of 2D- and 3D-NMR data of natural as well as 90% (13)C enriched material. B-type prymnesins lack a complete 1,6-dioxadecalin core unit, which is replaced by a short acyclic C2 linkage compared to the structure of the original prymnesins. Comparison of the bioactivity of prymnesin-2 with prymnesin-B1 in an RTgill-W1 cell line assay identified both compounds as toxic in the low nanomolar range. Chemical investigations by liquid chromatography high-resolution mass spectrometry (LC-HRMS) of 10 strains of P. parvum collected worldwide showed that only one strain produced the original prymnesin-1 and -2, whereas four strains produced the novel B-type prymnesin. In total 13 further prymnesin analogues differing in their core backbone and chlorination and glycosylation patterns could be tentatively detected by LC-MS/HRMS, including a likely C-type prymnesin in five strains. Altogether, our work indicates that evolution of prymnesins has yielded a diverse family of fish-killing toxins that occurs around the globe and has significant ecological and economic impact.
微小原甲藻（Prymnesium parvum）的大量繁殖在全球范围内导致毁灭性的鱼类死亡，据怀疑这是由超大型梯架式聚醚毒素原甲藻毒素-1和-2引起的。然而，自二十年前最初描述以来，这些毒素仅在极少数情况下从微小原甲藻中被检测到。在此，我们基于对天然以及90%（13）C富集材料的二维和三维核磁共振数据的广泛分析，报告了一种新型B型原甲藻毒素的分离和表征。B型原甲藻毒素缺乏完整的1,6 - 二氧杂十氢化萘核心单元，与原始原甲藻毒素的结构相比，该单元被一个短的无环C2连接所取代。在RTgill - W1细胞系试验中对原甲藻毒素-2和原甲藻毒素-B1的生物活性进行比较，结果表明这两种化合物在低纳摩尔范围内均具有毒性。通过液相色谱高分辨率质谱（LC - HRMS）对全球收集的10株微小原甲藻进行化学研究表明，只有一株产生原始的原甲藻毒素-1和-2，而有四株产生新型B型原甲藻毒素。通过LC - MS/HRMS总共还可以初步检测到另外13种原甲藻毒素类似物，它们在核心骨架以及氯化和糖基化模式上有所不同，其中包括在五株菌株中可能存在的C型原甲藻毒素。总之，我们的工作表明原甲藻毒素的进化产生了一个全球分布的、具有显著生态和经济影响的杀鱼毒素多样化家族。
