Dziga Dariusz, Maksylewicz Anna, Maroszek Magdalena, Budzyńska Agnieszka, Napiorkowska-Krzebietke Agnieszka, Toporowska Magdalena, Grabowska Magdalena, Kozak Anna, Rosińska Joanna, Meriluoto Jussi
Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland.
Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland.
Ecotoxicol Environ Saf. 2017 Nov;145:420-430. doi: 10.1016/j.ecoenv.2017.07.046. Epub 2017 Jul 31.
Cyanobacterial blooms and cyanotoxins occur in freshwater lakes and reservoirs all over the world. Bacterial degradation of microcystins (MC), hepatotoxins produced by several cyanobacterial species, has also been broadly documented. However, information regarding MC biodegradation in European water bodies is very limited. In this paper, the occurrence and identification of MC biodegradation products was documented for 21 European lakes and reservoirs, many of which have well-documented cyanobacterial bloom histories. Varying cyanobacterial abundance and taxonomical composition were documented and MC producers were found in all the analysed samples. Planktothrix agardhii was the most common cyanobacterial species and it formed mass occurrences in four lakes. MC biodegradation was observed in 86% of the samples (18 out of 21), and four products of dmMC-LR decomposition were detected by HPLC and LC-MS methods. The two main products were cyclic dmMC-LR with modifications in the Arg-Asp-Leu region; additionally one product was recognized as the tetrapeptide Adda-Glu-Mdha-Ala. The composition of the detected products suggested a new biochemical pathway of MC degradation. The results confirmed the hypothesis that microcystin biodegradation is a common phenomenon in central European waters and that it may occur by a mechanism which is different from the one previously reported. Such a finding implies the necessity to develop a more accurate methodology for screening bacteria with MC biodegradation ability. Furthermore, it warrants new basic and applied studies on the characterization and utilization of new MC-degrading strains and biodegradation pathways.
蓝藻水华和蓝藻毒素在世界各地的淡水湖泊和水库中都有发生。微囊藻毒素（MC）是由几种蓝藻物种产生的肝毒素，其细菌降解也有广泛的文献记载。然而，关于欧洲水体中微囊藻毒素生物降解的信息非常有限。在本文中，记录了21个欧洲湖泊和水库中微囊藻毒素生物降解产物的出现和鉴定情况，其中许多湖泊和水库都有详细记录的蓝藻水华历史。记录了不同的蓝藻丰度和分类组成，并且在所有分析样本中都发现了微囊藻毒素产生菌。阿氏浮丝藻是最常见的蓝藻物种，在四个湖泊中大量出现。在86%的样本（21个样本中的18个）中观察到微囊藻毒素生物降解，通过高效液相色谱法（HPLC）和液相色谱 - 质谱法（LC - MS）检测到了去甲基微囊藻毒素 - 亮氨酸 - 精氨酸（dmMC - LR）分解的四种产物。两种主要产物是在精氨酸 - 天冬氨酸 - 亮氨酸区域有修饰的环状dmMC - LR；此外，一种产物被鉴定为四肽Adda - 谷氨酸 - 甲基脱氢丙氨酸 - 丙氨酸。检测到的产物组成表明了微囊藻毒素降解的一种新的生化途径。结果证实了以下假设：微囊藻毒素生物降解在中欧水域是一种常见现象，并且其发生机制可能与先前报道的不同。这一发现意味着有必要开发一种更准确的方法来筛选具有微囊藻毒素生物降解能力的细菌。此外，这也需要对新的微囊藻毒素降解菌株和生物降解途径的表征及利用开展新的基础研究和应用研究。
