Laboratory of Photo-Catalytic Processes and Environmental Chemistry, Institute of Nanoscience & Nanotechnology, National Center for Scientific Research "Demokritos", Patriarchou Grigoriou E & 27 Neapoleos Str, 15310, Agia Paraskevi, Athens, Greece.
Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
Chemosphere. 2020 Jun;248:125961. doi: 10.1016/j.chemosphere.2020.125961. Epub 2020 Jan 20.
Cyanobacteria can form extensive blooms in water with concurrent production and release of a large number of chemically diverse and bioactive metabolites, including hazardous toxins. Significant number of the metabolites belongs to non-ribosomal peptides, with unique residues, unusual structures and great potential for biotechnological application. The biosynthetic pathways of the peptides generate tens of variants, but only part of them has been identified. Microginins are an understudied class of cyanobacterial linear peptides with a characteristic decanoic acid derivative amino acid residue in their structure. In this study, cyanobacterial blooms and isolated strains from Greek lakes were analyzed for the presence of microginins by liquid chromatography coupled to hybrid triple quadrupole/linear ion trap mass spectrometer (LC-qTRAP MS/MS). Microginin structures were elucidated based on the obtained fragmentation spectra. A large number of microginins occurred in blooms of Greek freshwaters and the most frequently detected were Microginin FR1 (70% of samples), Microginin T1 (52%), Microginin 565B (52%), Microginin T2 (43%), and Microginin 565A (43%). Additionally, nine cyanobacterial strains i.e. Nostoc oryzae, Synechococcus sp., Microcystis aeruginosa, Microcystis viridis, and five Microcystis sp., were found to produce microginins. Thirty-six new microginin structures were characterized out of fifty-one totally detected variants. This is the first time that such a diversity of microginins is reported to be present in water bodies. Results clearly demonstrate the great metabolomic potential of cyanobacteria that inhabit Greek freshwaters and significantly expand the knowledge of cyanobacterial secondary metabolites with regards to the class of microginins.
蓝藻可以在水中大量繁殖，同时产生和释放大量化学性质多样且具有生物活性的代谢物，包括有害毒素。大量代谢物属于非核糖体肽，具有独特的残基、不寻常的结构和巨大的生物技术应用潜力。这些肽的生物合成途径产生了数十种变体，但只有一部分得到了鉴定。微囊藻素是一类研究较少的蓝藻线性肽，其结构中含有特征性的癸酸衍生物氨基酸残基。在这项研究中，通过液相色谱-混合三重四极杆/线性离子阱质谱（LC-qTRAP MS/MS）分析了来自希腊湖泊的蓝藻水华和分离株中是否存在微囊藻素。根据获得的碎片谱图阐明了微囊藻素的结构。大量的微囊藻素存在于希腊淡水的水华，其中最常检测到的是 Microginin FR1（70%的样本）、Microginin T1（52%）、Microginin 565B（52%）、Microginin T2（43%）和 Microginin 565A（43%）。此外，还发现了 9 株蓝藻产生微囊藻素，即鱼腥藻、聚球藻、铜绿微囊藻、绿色微囊藻和 5 株微囊藻。从总共检测到的 51 种变体中，鉴定出 36 种新的微囊藻素结构。这是首次报道如此多样化的微囊藻素存在于水体中。研究结果清楚地表明，栖息在希腊淡水中的蓝藻具有巨大的代谢组学潜力，并显著扩展了关于微囊藻素类别的蓝藻次生代谢物的知识。
