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甲藻赤潮及其毒素的产生机制及夜光藻氮代谢途径 总被引：8，自引：1，他引：7
依据８０－９０年代国内外有关资料,从甲藻分类、甲藻室内培养、甲藻毒素及其生物合成上方面,综合评述甲藻赤潮及其毒素最新研究进展;并结合作者自己的研究结果,对夜光藻赤潮的生产与调控机理模型提出一种理论假说,这一假说的验证将为全面阐明夜光藻生活史及赤潮成因和机理提供分子水平的框架路径。 相似文献
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Environmental inequality scholarship has paid little attention to the disproportional exposure of immigrants in the United States (U.S.) to unfavorable environmental conditions. This study investigates whether new international migrants in the U.S. are exposed to environmental hazards and how this pattern varies among immigrant subpopulations (e.g., Hispanics, Asian, European). We combine sociodemographic information from the American Community Survey with toxicity-weighted chemical concentrations (Toxics Release Inventory) to model the relationship between toxin exposure and the relative population of recent immigrants across Public Use Microdata Areas (PUMAs, n = 2054) during 2005–2011. Results from spatial panel models show that immigrants tend to be less exposed to toxins, suggesting resilience instead of vulnerability. This pattern was pronounced among immigrants from Europe and Latin America (excluding Mexico). However, our results revealed that Mexican immigrants are disproportionately exposed to environmental hazards in wealthy regions. 相似文献
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Ian R. Falconer 《洁净——土壤、空气、水》2005,33(1):64-71
Microcystins are cyclic heptapeptide toxins produced by a range of cyanobacterial genera. These cyanobacteria occur naturally in drinking water reservoirs subject to eutrophication, and in rivers and natural lakes. Because of the diversity of organisms, the toxins occur, from oligo‐mesotrophic lakes in North Temperate latitudes, to hypertrophic tropical ponds. The toxins are responsible for numerous cases of injury and death of domestic animals, and human poisoning from drinking water. The initial poisoning includes hepatic cell death. This leads to secondary effects from liver deficiency, including jaundice and photosensitisation. The toxic effects are largely due to inhibition of phosphatase enzymes, acting to regulate protein phosphorylation. The consequences include structural damage, apoptosis and, at lower concentrations, cell cycle effects and tumour promotion. As there is no clear evidence for direct carcinogenesis by microcystins, they are classed as non‐carcinogenic toxins in drinking water. Guideline Values for safe drinking water are derived from data for subchronic rodent toxicity, using the No Observed Adverse Effect Level (the highest dose giving no toxicity). To this dose are applied uncertainty factors, to calculate a Tolerable Daily Intake. On the basis of a standard bodyweight and water consumption the Guideline Value is determined for drinking water. For microcystin‐LR the WHO have set a provisional Guideline Value of 1 μg/L for drinking water. 相似文献
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Haberkorn H Tran D Massabuau JC Ciret P Savar V Soudant P 《Marine pollution bulletin》2011,62(6):1191-1197
The complexity of the relationships between Alexandrium minutum (A.m.) concentration in the water ([A.m.]w), Paralytic Shellfish Poisoning contamination in the digestive gland ([PSP]dg) and valve behavior was explored in oysters Crassostrea gigas. Two experiments were conducted, during which oysters’ valve behaviour were analyzed. Oysters, first acclimated for 10-days with the non harmful microalgae Heterocapsa triquetra (H.t.), were exposed to four microalgae mixtures at constant total concentrations of 10 × 103 cells ml−1 (experiment-1) and 5 × 103 cells ml−1 (experiment-2): 100% A.m.; 50% A.m.-50% H.t.; 25% A.m.-75% H.t.; 100% H.t. At the end of experiment-2, [PSP]dg were measured.At 10 × 103 cells ml−1, the microalgal ingestion decreased (p < 0.05) with increasing [A.m.]w but not at 5 × 103 cells ml−1 (p > 0.05). The frequency of microclosures specifically increased with [A.m.]w (p < 0.05) and the opening duration with [PSP]dg (p < 0.0001). Oysters exhibiting the maximum increase in opening duration also exhibited the highest [PSP]dg. The results are discussed in terms of oyster physiology and origin of the behavioral response. 相似文献
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Bloom‐forming cyanobacteria have been observed in eutrophic waterbodies including drinking water reservoirs all over the world. In this connection investigations about the relevance of intra‐ and extracellular cyanotoxins for drinking water treatment were carried out in laboratory‐ and pilot‐scale experiments. An algae growth phase depended toxin release from cyanobacteria was obtained naturally caused from cultured cyanobacteria (Microcystis aeruginosa) and in a eutrophic reservoir containing Planktothrix rubescens. Results from laboratory‐scale tests using cultivated cyanobacteria and pilot‐scale experiments at a eutrophic reservoir underline the induced toxin release during conventional water treatment. Additional to the known toxin release using pre‐oxidation, it was obtained the first time that the application of flocculation/filtration also effects in toxin release under the conditions investigated, possibly caused by turbulences in pipes and pressure gradients in filters. 相似文献
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以实验室单种培养的强壮前沟藻为对象,研究了强壮前沟藻毒素的来源,分析了藻毒素浓度与溶血活性的相关性,研究了理化因子对藻毒素溶血活性的影响。结果表明,溶血活性随着强壮前沟藻细胞的增殖呈上升的趋势,细胞内容物和细胞碎片的溶血活性显著高于去藻过滤液,强壮前沟藻毒素主要来源于衰亡期的细胞内容物和细胞碎片,并存在浓度相关的溶血性。强壮前沟藻毒素的溶血活性不存在光敏感性。随着pH的上升,毒素溶血活性呈降低趋势。Ca2+、Mn2+、Cu2+抑制了强壮前沟藻毒素溶血活性,而Co2+、Zn2+显著的增强了溶血活性,Mg2+对其溶血活性的影响不显著。EDTA对强壮前沟藻毒素的溶血活性有显著的促进作用。 相似文献
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