黄河水源水浮游藻类及藻类毒素污染状况动态研究

目的 :探讨黄河水源水浮游藻类和藻毒素污染状况及影响因素。方法 :于 1998年 5～ 12月在河南省S市、Z市、P市水源水设采样点 ,对水源水浮游藻类、藻类毒素污染情况及总氮、总磷、COD等指标进行了连续检测。结果 :河南省黄河水源水总氮检出范围为 2 5 7～ 6 .79mg/L ,总磷的检出范围为 0 0 1～ 0 .32mg/L ,蓝藻和绿藻为浮游藻类的优势种群。MC的阳性率 ( >2 0ng/L)为 82 6 1% ,最高达到 95 7 9ng/L。结论 :按照Carlson提出的富营养化指数TSI(TP)判定标准 ,结合TN、TP、COD及藻类密度等指标 ,认为河南省境内黄河水源水已呈现富营养化特征。磷是黄河水源水浮游藻类生长的主要限制因子 ,控制黄河水源水富营养化应以控制磷为主。     

Toxicity thresholds for juvenile freshwater mussels Echyridella menziesii and crayfish Paranephrops planifrons,after acute or chronic exposure to Microcystis sp

Survival of juvenile freshwater mussels (Echyridella menziesii (Gray, 1843) formerly known as Hyridella menziesi) and crayfish (Paranephrops planifrons, White, 1842) decreased after four days exposure to microcystin‐containing cell‐free extracts (MCFE) of Microcystis sp. at concentrations typical of severe cyanobacterial blooms. Crayfish survival was 100, 80, and 50% in microcystin concentrations of 1339, 2426, and 11146 μg L^?1 respectively, and shade‐ and shelter‐seeking behavior was negatively affected when concentrations were ≥2426 μg L^?1. Mussel survival decreased to 92% and reburial rates decreased to 16% after exposure for 96 h to MCFE containing microcystins at concentrations of 5300 μg L^?1. Crayfish survival was 100% when fed freeze‐dried Microcystis sp. incorporated into an artificial diet (6–100 μg microcystin kg^?1 ww) at dietary doses from 0.03 to 0.55 μg g^?1 body weight d^?1 for 27 days. Specific growth rate was significantly lower in crayfish fed ≥0.15 μg g^?1 body weight day^?1 compared with controls, but not compared with a diet incorporating nontoxic cyanobacteria. Microcystins accumulated preferentially in crayfish hepatopancreas and mussel digesta as MCFE or dietary concentrations increased. These laboratory data indicate that, assuming dissolved oxygen concentrations remain adequate, and no simultaneous exposure to live Microcystis sp. cells, cell‐free microcystins will only be a significant stressor to juvenile crayfish and mussels in severe Microcystis sp. blooms. In contrast, crayfish were negatively affected by relatively low concentrations of microcystins in artificial diets compared with those measured locally in benthic cyanobacterial mats. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 487–502, 2014.     

ADMAdda5]-microcystins in Planktothrix agardhii strain PH-123 (cyanobacteria)--importance for monitoring of microcystins in the environment

Two major and two minor microcystins (MCYST) were isolated from a hepatotoxic Danish strain of Planktothrix agardhii (Gomont) Anagnostidis et Komárek by reversed-phase high-performance liquid chromatography. The microcystins were characterized by UV spectroscopy, amino acid analysis, fast atom bombardment mass spectrometry (FABMS), and high-resolution FABMS. The major microcystins were further analysed by collisionally induced tandem electrospray ionization MS. The microcystins were found to be demethylated variants of MCYST-HtyR (homotyrosine-arginine) and MCYST-LR (leucine-arginine). The two major microcystins contained an acetyl-demethyl variant (ADMAdda) of 3-amino-9-acetoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda). This is the first report of [ADMAdda5]-microcystins in Planktothrix. The two [ADMAdda5]-microcystins inhibited protein phosphatase activity but showed low cross-reactivity with antibodies of an enzyme-linked immunosorbent assay (ELISA), emphasizing the potential underestimation of the toxicity of natural blooms dominated by Planktothrix when microcystin content is quantified using only an ELISA.     

福建省部分水源微囊藻毒素污染调查

目的 报告福建省部分饮用水水源微囊藻毒素污染状况调查结果,探讨饮用水水源微囊藻毒素的危害及预防措施.方法 1998,2000年在厦门同安肝癌高发区抽样采集浅井水49份、自来水4份、水库水3份,竞争酶联免疫吸附法（ELISA）测定水样中微囊藻毒素;2001年8-9月份采集福州山仔水库微囊藻水华,小鼠生物法测定微囊藻水华急性毒性,高效液相色谱法定性、定量测定微囊藻毒素类型和含量.结果 厦门同安农村饮用水水源普遍存在微囊藻毒素污染,夏季藻类生长高峰期,水库水微囊藻毒素检出率100%,浅井水检出率77.5%;同安水源中优势藻为颤藻,其次为微囊藻.福州山仔水库微囊藻水华LD50为9.9 g藻浆/kg,平均死亡时间2.5 h.每克鲜藻浆含微囊藻毒素20.5μg,主要毒素类型为MC-RR,其次为MC-LR和MC-YR.结论 福建省部分饮用水水源存在微囊藻毒素污染,山仔水库微囊藻毒素主要类型为MC-RR,有明显的肝毒性.     

Influence of drinking water composition on quantitation and biological activity of dissolved microcystin (cyanotoxin)

Toxic cyanobacteria in aquatic environments have been implicated in many poisoning incidents of livestock, wildlife, and domestic animals. Microcystins (MCYSTs) in water supplies represent a risk to public health. This work investigated the effect of water composition on the quantitation and biological activity of MCYSTs analyzed by different methods (HPLC, ELISA, and protein phosphatase 1 inhibition assay). Different MCYST concentrations were added to deionized water and quantified, confirming the efficiency of these analytical methods. MCYST concentrations diluted in drinking water had reduced detection by all methods tested. The drinking water used contained a free chlorine concentration of 2.5 mg/L and an Fe concentration of 0.45 mg/L, and the conductivity was 69.8 microS cm(-1), whereas in deionized water, free chlorine and Fe were not detectable, and the conductivity was 1.6 microS cm(-1). Drinking water also interfered with the biological activity of MYCSTs, as these toxins showed reduced protein phosphatase-1 inhibition. A free chlorine concentration of 2.5 mg/L in deionized water was completely effective in preventing any detection of 10 microg/L of added MCYSTs. Fe and Al ions also were very effective in reducing MCYST detection. The chemical composition of drinking water thus affected MCYST detection, indicating a significant reduction in quantitation of this molecule either because of its decomposition or through complexation with metal ions.     

Measurement of phycocyanin fluorescence as an online early warning system for cyanobacteria in reservoir intake water

Cyanobacterial blooms in drinking water reservoirs may cause a variety of water quality problems, including those of taste and odor, and can compromise the water supply destined for human consumption. In response to this problem an online monitoring tool for analyzing the cyanobacterial concentration in intake water is of practical value. This study demonstrated a positive correlation between phycocyanin fluorescence and cyanobacterial biomass during Microcystis aeruginosa blooms in a lowland drinking water reservoir, using online detection. The highest correlation coefficients were found for a cyanobacterial biomass concentration below 15 mg freshweight/L, indicating that this method can be an effective early warning system. Rapid changes in fluorescence were observed when wind drift moved higher cyanobacterial concentrations into the water intake, indicating that fluorescence could be employed as a quick warning for changed requirements for plant operations.     

微囊藻毒素的毒性以及水生生物的富集作用

微囊藻毒素是微囊藻等淡水藻类产生的一类具有生物活性的环状七肽物质 ,它能抑制蛋白磷酸酶 1和蛋白磷酸酶 2A的活性 ,打破细胞内蛋白磷酸化 脱磷酸化的平衡 ,引起肝损伤甚至肝坏死。而且它是强促癌剂。然而 ,其毒性及富集作用很少受到人们的重视。本文拟综述微囊藻毒素的毒性及其生物富集作用     

淡水湖泊微囊藻毒素的污染和毒理学研究

微囊藻毒素是淡水湖泊蓝藻产生的一类肽类毒素 ,它的产生受到藻类的遗传和环境因素共同影响。微囊藻毒以肝脏为靶器官 ,通过多种作用引起肝细胞坏死 ,抑制蛋白磷酸酶 1(PP1)和蛋白磷酸酶 2A(PP2A)的活性 ,具有致癌性 ,是肿瘤促进剂。微囊藻及其毒素的污染已成为一个受人关注的公共卫生问题。由于微囊藻毒素污染的广泛性、持续性以及它所具有的热稳定性和水溶性 ,可能存在潜在的食品安全问题。本文综述了微囊藻及其毒素的污染、微囊藻毒素的产生原因和毒理学研究现状 ,预防的基本原则 ,并就其在食品安全方面将要开展的工作提出了一些建议     

Serologic evaluation of human microcystin exposure

Microcystins are among the most commonly detected toxins associated with cyanobacteria blooms worldwide. Two episodes of intravenous microcystin exposures occurred among kidney dialysis patients during 1996 and 2001. Analysis of serum samples collected during these episodes suggests that microcystins are detectable as free and bound forms in human serum. Our goal was to characterize the biochemical evidence for human exposure to microcystins, to identify uncertainties associated with interpretation of these observed results, and to identify research needs. We analyzed serum samples using enzyme-linked immunosorbent assay (ELISA) methods to detect free microcystins, and gas chromatography/mass spectrometry (GC/MS) to detect 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB). MMPB is derived from both free and protein-bound microcystins by chemical oxidation, and it appears to represent total microcystins present in serum. We found evidence of free microcystins in patient serum for more than 50 days after the last documented exposure. Serum concentrations of free microcystins were consistently lower than MMPB quantification of total microcystins: free microcystins as measured by ELISA were only 8-51% of total microcystin concentrations as detected by the GC/MS method. After intravenous exposure episodes, we found evidence of microcystins in human serum in free and protein-bound forms, though the nature of the protein-bound forms is uncertain. Free microcystins appear to be a small but variable subset of total microcystins present in human serum. Research is needed to elucidate the human toxicokinetics of microcystins, in part to determine how observed serum concentrations can be used to estimate previous microcystin exposure.     

Phosphoprotein analysis for investigation of in vivo relationship between protein phosphatase inhibitory activities and acute hepatotoxicity of microcystin-LR

Microcystin-LR (MCLR) produced by freshwater cyanobacteria is a potent hepatotoxin and inhibits protein serine/threonine phosphatases 1 and 2A (PP1 and PP2A). Okadaic acid (OA) is a similar phosphatase inhibitor, which has less affinity to PP1 than PP2A. MCLR and OA behave similarly with primary culture hepatocytes with the induction of phosphorylation of the cytokeratins, morphological changes, and apoptosis. The purpose of this study was to investigate the in vivo relationship between the protein phosphatase inhibitory activities and the acute hepatotoxicity of MCLR compared to OA. MCLR and OA were intraperitoneally administrated to mice at approximately 220 microg/kg. After 30 min, the liver of only the MCLR-treated mouse was dark-colored and heavier than that of the control mouse. Subsequently, the phosphoproteins of the mouse liver were chemically modified with reversible biotinylation reagent and selectively analyzed by LC/MS/MS. Consequently, the phosphorylated Ser 354 of formyltetrahydrofolate dehydrogenase, which is an abundant enzyme in the liver cytoplasm, was observed in the MCLR- and the OA-treated mice 9.5 and 5.3 times more intensely than in the control mouse respectively, suggesting that MCLR and OA inhibited PP2A and induced the resulting phosphorylation. These results supported the hypothesis that the acute hepatotoxicity is possibly caused by the PP1 inhibition, and not by the PP2A inhibition.