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微囊藻毒素的生态学和毒理学研究
Alternative TitleEcological and toxicological studies on microcystins
王青
Subtype硕士
Thesis Advisor谢平
2009-05-28
Degree Grantor中国科学院水生生物研究所
Place of Conferral水生生物研究所
Keyword微囊藻毒素 贡湖 季节变化 大鼠 静脉注射 组织分布
Abstract随着水体富营养化日益严重,有毒蓝藻水华引起的污染事件在世界范围内频繁发生,其产生的毒素对生物有潜在的危害。微囊藻毒素(Microcystins,简称MCs)是一类由蓝藻产生的具有肝毒性的生物毒素。本研究主要分为两个部分,微囊藻毒素的生态学研究和毒理学研究。 第一部分是对太湖贡湖湾的微囊藻毒素的野外调查研究,主要包括胞内毒素、胞外毒素含量的季节变化,并讨论理化和生物因子对微囊藻毒素的动力学影响以及这些变化下可能存在的机制。水华的爆发、水中毒素浓度的变化有着明显的季节性,在研究期间(2008.1-2008.12),7-10月天气较炎热的时候MCs浓度较高,另外,MCs浓度和微囊藻生物量都在10月份达到最高。在布设的采样点中,较封闭、水体流动性小的水域相比于开阔区的水域,MCs毒素含量较高。微囊藻生物量、微囊藻胞内和胞外毒素含量都与水温显著正相关,可见蓝藻爆发与温度关系密切。与微囊藻生物量显著相关的NO3、TDN和TP均与胞内、胞外毒素浓度显著相关,可见N 、P浓度通过影响生物量而间接地影响MCs的产生。贡湖湾MCs含量最大值高达17μg/L MC-LR,大大超过了世界卫生组织(WHO)提供的饮用水安全标准(1μg/L MC-LR)。因此,为了减少蓝藻毒素对水生动物和人类的危害,控制贡湖湾微囊藻毒素的污染已成为当务之急。 第二部分是研究静脉注射条件下微囊藻毒素在大鼠体内的各组织器官分布和代谢规律的室内实验,讨论这些变化下可能存在的抗毒和解毒机制。通过静脉注射MC提取液(80 μg MC-LReq./kg bw),采用HPLC-MS法测定了注射后1、2、4、6、12和24 h大鼠各组织器官中的游离的MCs含量。静脉注射后,MCs很快进入了血液循环系统并被迅速运送到大鼠的各个器官,表现为各组织器官不同的毒素含量水平。MCs的最大含量(MC-RR+MC-LR)出现在肾中(0.034- 0.295mg/gDW),其次是肺(0.007-0.067mg/gDW)、胃(0.010- 0.058mg/gDW) 和肝(0.003-0.052 mg/g DW)。大鼠肾脏中MCs含量远远高于肝中,并且毒素浓度有2个峰值(2h和24h)出现,表明大鼠肾脏可能是MCs的主要排除器官。MCs在大鼠肝脏内的积累和代谢迅速,在性腺中的MCs较难代谢,表明MCs可能产生生殖毒性。肺、心、肠、脑和脾中有不同程度的MCs累积,表明MCs对这些器官存在潜在毒性。
Other AbstractThe occurrence of heavy cyanobacterial blooms in eutrophic fresh waters has been a worldwide problem. Microcystins (MCs) produced by cyanobacteria are potent hepatotoxins.This study mainly contains two parts, ecological and toxicological studies of MCs. The first part was a field survey of MCs in Gonghu Bay of Taihu in China from Jan. 2008 to Dec.2008. Seasonal variations of intracellular MCs and extracellular MCs were studied with disucssion on the possible effects of physico-chemical and biological factors underlying these variations. Water temperature was an important factor in determining cyanobacterial biomass and toxin production. During the study period, higher MCs concentration was found in summer and autumn, and Microcystis biomass and MCs concentrations reached peaks in October. Among the sampling-sites in Gonghu Bay, MCs concentration was higher in the water areas with less fluidity. Microcystis biomass, intracellular and extracellular MCs were significantly correlated with water temperature, suggesting that breakout of water bloom was closely related with temperature. There were significant correlations among N or P concentrations, Microcystis biomass and MCs content, suggesting that N and P levels affected MCs production through influencing Microcystis biomass. In Gonghu Bay, the maximum MCs concentration reached as high as 17μg/L MC-LR and was considerably higher than the drinking water safety standard recommended by WHO. So it is urgently needed to monitor MC pollution in Lake Taihu and to reduce the exposure risk of cyanobacterial toxins to both aquatic animals and human beings. The second part was a laboratory study on distribution and deputation patterns of MCs in various tissues of Wistar rats via intravenous injection with discussion on the possible mechanisms underlying these patterns. Rats were injected intravenously (i.v.) with extracted MCs at a dose of 80 μg MC-LRequivalent/kg body weight. Free MCs concentrations in various tissues were detected at 1, 2, 4, 6, 12 and 24 h post-injection using liquid chromatography–mass spectrometry (LC–MS). MCs entered into the circulatory system rapidly after intravenous injection, and were transported to various organs, which subsequently resulted in different levels of MCs in various tissues. The highest concentration of MCs was found in kidney (0.034–0.295 mg/g dry weight), followed by lung (0.007–0.067 mg/g dry weight), stomach (0.010–0.058 mg/g dry weight) and liver (0.003–0.052 mg/g dry weight). MCs concentration was higher in kidney than in liver during the experiment, and two peaks of MCs concentration (at 2 and 24 h, respectively) were observed in kidney, indicating that MCs can be excreted directly via kidney of rat. Rapid accumulation and degradation of MCs were found in liver of the rats. It was difficult for MCs to be eliminated from gonad, hence MCs may cause chronic toxicity in the reproductive system.Though heart,intestine, spleen, brain and stomach contained less than 0.2% of injected MCs during the whole experiment stage, the presence of MCs in these tissues represents potential damage to them.
Pages79
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/12482
Collection学位论文
Recommended Citation
GB/T 7714
王青. 微囊藻毒素的生态学和毒理学研究[D]. 水生生物研究所. 中国科学院水生生物研究所,2009.
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