Cyanotoxins are chemical compounds produced by cyanobacterial mats grown in aquatic ecosystems. These may threaten human health and aquatic organisms. Extraction of these toxins is usually associated with many difficu...Cyanotoxins are chemical compounds produced by cyanobacterial mats grown in aquatic ecosystems. These may threaten human health and aquatic organisms. Extraction of these toxins is usually associated with many difficulties due to their concentration in aquatic ecosystems. This study is designed to provide suitable and effective extraction procedures that can effectively extract low concentration cyanotoxin from water and bacterial cells. The methodology is based on collecting raw material of cyanobacterial mats from naturally growing sites such as Wadi Gaza along with 16 liters of aquatic surrounding media. The materials were left in the Lab for 24 - 48 h for stabilization of the mats. The floating mats were collected using special funnel and allowed to air drying. The aqueous phase was extracted by liquid/liquid extraction using solvent mixture (hexane + ethylacetate 10% w:w), and by liquid solid extraction using several types of organoclays complexes. The solid phase was extracted by acetone and ultrasonic device. Results showed some difficulties were associated with liquid/liquid extraction whereas effective and easy extraction procedures were obtained by liquid solid extraction using either organoclay complex or activated charcoal. In contrast combination of both solid materials did not show improvement in the extracted cyanotoxin. Thus we recommend the use of organoclays or activated charcoal separately for extracting cyanotoxin. Further improvement of extraction can be tailored by using a specific organoclay complex that has some similarity in the chemical structure between the pre-adsorbed organic cation to the clay mineral and the chemical structure of cyanotoxin.展开更多
The management of cyanobacteria and potential exposure to associated biotoxins requires the allocation of scarce resources across a range of freshwater resources within various jurisdictions. Cost effective and reliab...The management of cyanobacteria and potential exposure to associated biotoxins requires the allocation of scarce resources across a range of freshwater resources within various jurisdictions. Cost effective and reliable methods for sample processing and analysis form the foundation of the protocol yielding reliable data from which to derive important decisions. In this study the utilization of new methods to collect, process and analyze samples enhanced our ability to evaluate cyanobacterial populations. Extraction of phycocyanin using the single freeze thaw method provided more accurate and precise measurements (CV 4.7% and 6.4%), offering a simple and cost-effective means to overcome the influence of morphological variability. In-vacuo concentration of samples prior to ELISA analysis provided a detection limit of 0.001 μg·L?1 MC. Fractionation of samples (?1) = ?0.279 + (1.368 ? Log PC (μg·L?1) while in an Aphanizomemon spp. dominant system Log MC (ng·L?1) = 0.385 + (0.449 ? Log PC (μg·L?1). These methods and sampling protocol could be used in other aquatic systems across a broader regional landscape to estimate the levels of microcystins.展开更多
21世纪以来,太湖地区蓝藻的爆发严重影响了当地水资源的开发与利用。以太湖蓝藻为研究对象,以快速提取含蓝藻水体为目标,基于Landsat8影像对比分析了非蓝藻水体与含蓝藻水体光谱反射特征。含蓝藻水体在近红外波段表现出强反射率特征,而...21世纪以来,太湖地区蓝藻的爆发严重影响了当地水资源的开发与利用。以太湖蓝藻为研究对象,以快速提取含蓝藻水体为目标,基于Landsat8影像对比分析了非蓝藻水体与含蓝藻水体光谱反射特征。含蓝藻水体在近红外波段表现出强反射率特征,而在蓝光、绿光、红光、短波红外波段的反射特征与非蓝藻水体一致,据此提出了一种提取含蓝藻水体信息的方法——双红外水体指数(double infrared band water index,DIBWI)。基于太湖地区2014年和2017年的Landsat8影像,与归一化差异水体指数(normalized difference water index,NDWI)、改进的归一化差异水体指数(modified normalized difference water index,MNDWI)、新型水体指数(new water index,NWI)、多波段水体指数(multi-band water index,MBWI)和水体指数2015(water index 2015,WI2015)这5种水体指数提取结果进行了对比分析,并利用2013年、2016年和2018年3期数据进行验证。结果表明,DIBWI能够较完整地提取含蓝藻水体信息,有效消除蓝藻影响并能抑制背景地物,总体精度达到98%以上,Kappa系数大于0.95,可以为太湖地区水资源保护、合理开发利用提供技术支撑。展开更多
文摘Cyanotoxins are chemical compounds produced by cyanobacterial mats grown in aquatic ecosystems. These may threaten human health and aquatic organisms. Extraction of these toxins is usually associated with many difficulties due to their concentration in aquatic ecosystems. This study is designed to provide suitable and effective extraction procedures that can effectively extract low concentration cyanotoxin from water and bacterial cells. The methodology is based on collecting raw material of cyanobacterial mats from naturally growing sites such as Wadi Gaza along with 16 liters of aquatic surrounding media. The materials were left in the Lab for 24 - 48 h for stabilization of the mats. The floating mats were collected using special funnel and allowed to air drying. The aqueous phase was extracted by liquid/liquid extraction using solvent mixture (hexane + ethylacetate 10% w:w), and by liquid solid extraction using several types of organoclays complexes. The solid phase was extracted by acetone and ultrasonic device. Results showed some difficulties were associated with liquid/liquid extraction whereas effective and easy extraction procedures were obtained by liquid solid extraction using either organoclay complex or activated charcoal. In contrast combination of both solid materials did not show improvement in the extracted cyanotoxin. Thus we recommend the use of organoclays or activated charcoal separately for extracting cyanotoxin. Further improvement of extraction can be tailored by using a specific organoclay complex that has some similarity in the chemical structure between the pre-adsorbed organic cation to the clay mineral and the chemical structure of cyanotoxin.
文摘The management of cyanobacteria and potential exposure to associated biotoxins requires the allocation of scarce resources across a range of freshwater resources within various jurisdictions. Cost effective and reliable methods for sample processing and analysis form the foundation of the protocol yielding reliable data from which to derive important decisions. In this study the utilization of new methods to collect, process and analyze samples enhanced our ability to evaluate cyanobacterial populations. Extraction of phycocyanin using the single freeze thaw method provided more accurate and precise measurements (CV 4.7% and 6.4%), offering a simple and cost-effective means to overcome the influence of morphological variability. In-vacuo concentration of samples prior to ELISA analysis provided a detection limit of 0.001 μg·L?1 MC. Fractionation of samples (?1) = ?0.279 + (1.368 ? Log PC (μg·L?1) while in an Aphanizomemon spp. dominant system Log MC (ng·L?1) = 0.385 + (0.449 ? Log PC (μg·L?1). These methods and sampling protocol could be used in other aquatic systems across a broader regional landscape to estimate the levels of microcystins.
文摘21世纪以来,太湖地区蓝藻的爆发严重影响了当地水资源的开发与利用。以太湖蓝藻为研究对象,以快速提取含蓝藻水体为目标,基于Landsat8影像对比分析了非蓝藻水体与含蓝藻水体光谱反射特征。含蓝藻水体在近红外波段表现出强反射率特征,而在蓝光、绿光、红光、短波红外波段的反射特征与非蓝藻水体一致,据此提出了一种提取含蓝藻水体信息的方法——双红外水体指数(double infrared band water index,DIBWI)。基于太湖地区2014年和2017年的Landsat8影像,与归一化差异水体指数(normalized difference water index,NDWI)、改进的归一化差异水体指数(modified normalized difference water index,MNDWI)、新型水体指数(new water index,NWI)、多波段水体指数(multi-band water index,MBWI)和水体指数2015(water index 2015,WI2015)这5种水体指数提取结果进行了对比分析,并利用2013年、2016年和2018年3期数据进行验证。结果表明,DIBWI能够较完整地提取含蓝藻水体信息,有效消除蓝藻影响并能抑制背景地物,总体精度达到98%以上,Kappa系数大于0.95,可以为太湖地区水资源保护、合理开发利用提供技术支撑。
