RECETOX - Research Centre for Toxic Compounds in the Environment, Masaryk University, Faculty of Science, Brno, Czechia.
RECETOX - Research Centre for Toxic Compounds in the Environment, Masaryk University, Faculty of Science, Brno, Czechia.
Harmful Algae. 2016 Dec;60:157-166. doi: 10.1016/j.hal.2016.11.002. Epub 2016 Nov 23.
Phytoplankton can produce various bioactive metabolites, which may affect other organisms in the aquatic environment. This study provides the first information on the total retinoid-like activity associated with both intracellular and extracellular metabolites produced by selected phytoplankton species that could play a role in teratogenic effects and developmental disruption in exposed organisms. The studied species included a coccoid cyanobacteria (Microcystis aeruginosa), a filamentous cyanobacteria (Aphanizomenon gracile) and a green alga (Desmodesmus quadricauda), all of which commonly occur in freshwater bodies in Europe. Methanolic extracts from cellular material and extracellular exudates were prepared from cultures cultivated in two light-intensity variants with five replicates for each species. The retinoid-like activity was evaluated by in vitro assays along with chemical analyses of two potent retinoic acids (all-trans retinoic acid (ATRA) and 9cis-RA). The mean total retinoid-like activity of metabolites produced by the three studied species representing different phytoplankton taxonomic groups ranged from 705 to 5572ng ATRA equivalent/g dry matter corresponding to 0.064-0.234ng ATRA/10 cells. Retinoid-like activity was found in the cellular extracts of all species, while only the extracellular exudates of cyanobacteria exhibited detectable activity (41-1081ng ATRA/L). The greatest extracellular as well as total (extra- and intra- cellular together) retinoid-like activity was detected for Microcystis aeruginosa. The two potent retinoic acids studied were more frequently detected in cellular extracts than in extracellular exudates of all species. Their contribution to observed in vitro effects was relatively low for all tested samples (<10%), indicating a substantial contribution of other retinoid-like compounds to the overall activity. The results indicate possible influence of light intensity and cell density on the production of metabolites with retinoid-like activity and the cyanotoxin microcystin by the studied species. The recalculation of the results per dry weight, water volume, per 10 cells and biovolume enables a direct comparison of the retinoid-like activity distribution between extracts and exudates and the use of the data for risk assessment in water bodies.
浮游植物可以产生各种生物活性代谢物，这些代谢物可能会影响水生环境中的其他生物。本研究首次提供了与选定浮游植物物种的细胞内和细胞外代谢物相关的总类视黄醇活性的信息，这些代谢物可能在暴露生物的致畸作用和发育中断中发挥作用。研究的物种包括球形蓝藻（微囊藻）、丝状蓝藻（鱼腥藻）和绿藻（四尾栅藻），这些物种在欧洲的淡水水体中都很常见。从在两种光照强度下培养的培养物中制备细胞物质和细胞外渗出物的甲醇提取物，每种物种都有五个重复。通过体外测定和两种强效维甲酸（全反式维甲酸（ATRA）和 9cis-RA）的化学分析来评估类视黄醇活性。代表不同浮游植物分类群的三种研究物种产生的代谢物的总类视黄醇活性平均值范围为 705 至 5572ng ATRA 当量/g 干物质，对应于 0.064-0.234ng ATRA/10 个细胞。在所有物种的细胞提取物中都发现了类视黄醇活性，而只有蓝藻的细胞外渗出物表现出可检测的活性（41-1081ng ATRA/L）。微囊藻的细胞外和总类视黄醇活性（细胞外和细胞内一起）最大。在所研究的所有物种的细胞提取物中都发现了这两种强效维甲酸，而在所有物种的细胞外渗出物中都检测到了它们。对于所有测试样品，它们对观察到的体外效应的贡献相对较低（<10%），这表明其他类视黄醇化合物对整体活性有很大贡献。结果表明，光照强度和细胞密度可能会影响研究物种产生具有类视黄醇活性的代谢物和微囊藻毒素的情况。根据干重、水量、每 10 个细胞和生物量重新计算结果，可实现提取物和渗出物之间类视黄醇活性分布的直接比较，并将数据用于水体的风险评估。
