The first detection of potentially toxic Microcystis strains in two Middle Atlas Mountains natural lakes (Morocco)

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• 作者：Mountasser Douma ; Youness Ouahid…
• 关键词：Microcystis ; Microcystins ; mcy genes ; Toxigenic strains ; Natural lakes ; Morocco
• 刊名：Environmental Monitoring and Assessment
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：189
• 期：1
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Monitoring/Environmental Analysis; Environmental Management; Ecotoxicology; Atmospheric Protection/Air Quality Control/Air Pollution; Ecology;
• 出版者：Springer International Publishing
• ISSN：1573-2959
• 卷排序：189

文摘

Aguelmam Azizgza (LAZ) and Dayet Afourgah (DAF) are two Moroccan natural lakes located in a humid hydrographic basin of the Middle Atlas Mountains. Both are considered important reservoirs of plant and animal biodiversity. In addition, they are extensively used for recreational and fishing activities and as a water source for irrigation of agricultural crops. Recurrent cyanobacteria scum episodes in the two water bodies have been reported, Microcystis being the main genus in the scums. Here, we report on the toxic potential of three Microcystisaeruginosa strains isolated from those lakes: Mic LAZ and Mic B7 from LAZ and Mic DAF isolated from DAF. The toxic potential was checked by their microcystin (MC) content and the presence of mcy genes involved in MC synthesis. The identification and quantification of MC variants were performed by high-performance liquid chromatography-photo-diode array. The detection of mcy genes was achieved by whole-cell multiplex PCR that allowed the simultaneous amplification of DNA sequences corresponding to specific mcy regions. MC content of cultured cells, as MC-LR equivalents per gram cell biomass, was slightly higher in Mic LAZ (ca. 860) than in Mic B7 (ca. 700) and Mic DAF (ca. 690). Four MC variants were identified in the three isolates: MC-WR, MC-RR, MC-DM-WR, and MC-YR. The presence of toxic Microcystis strains in the two studied lakes may be regarded as an environmental and health hazard, especially during periods of bloom proliferation. It would be recommended the use of two complementary techniques, as those utilized herein (HPLC and mcy detection) to alert on highly probable toxicity of such lakes.