The biodegradation of microcystins in temperate freshwater bodies with previous cyanobacterial history
The biodegradation of microcystins in temperate freshwater bodies with previous cyanobacterial history
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DOI：
10.1016/j.ecoenv.2017.07.046
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发表时间：
2017-11-01
影响因子：
6.8
通讯作者：
Meriluoto, Jussi
中科院分区：
文献类型：
--
作者：
Dziga, Dariusz;Maksylewicz, Anna;Meriluoto, Jussi
蓝藻水华和蓝藻毒素发生在世界各地的淡水湖泊和水库。微囊藻毒素（MC）是由几种蓝藻产生的肝毒素，细菌降解也已被广泛报道。然而，关于MC在欧洲水体中生物降解的信息非常有限。在本文中，MC生物降解产物的发生和鉴定记录了21个欧洲湖泊和水库，其中许多有据可查的蓝藻水华的历史。不同的蓝藻丰度和分类组成的记录和MC生产商被发现在所有的分析样品。浮游发丝菌是最常见的蓝藻种类，在四湖中形成了群体性分布。MC的生物降解观察到86%的样品（18出21），和四个产品的dmMC-LR分解的HPLC和LC-MS方法检测。两种主要产物是在Arg-Asp-Leu区域具有修饰的环状dmMC-LR;另外一种产物被识别为四肽Adda-Glu-Mdha-Ala。检测到的产物的组成表明MC降解的一个新的生化途径。结果证实了微囊藻毒素生物降解是中欧沃茨中的一种常见现象的假设，它可能发生的机制，这是不同于以前报道的。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MC生物降解能力的细菌。此外，它保证新的基础和应用研究的表征和利用新的MC降解菌株和生物降解途径。
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.