|其他题名: ||Ecological and toxicological studies on microcystins|
2. 湖水中总MC的含量（胞外毒素 + 胞内毒素）和藻细胞毒素含量与生物量乘积之间具有显著正相关性关系，湖水中MC的含量可能受到水体中产毒藻类生物量和产毒藻细胞毒素含量的共同调控，而且影响藻细胞产毒的因子不一定会影响产毒藻细胞的生物量。
3. 星云湖中MC含量最大值高达41.42 µg l-1，比目前世界其他区域爆发微囊藻水华的湖泊水体中的最高含量还要高。因此，为了减少蓝藻毒素暴露对水生动物和人类的危害，控制星云湖微囊藻毒素的污染和已成为一个亟待解决的问题。
1. 本次急性中毒实验通过向腹腔注射两种不同剂量的粗提的MC抽提液（200和500 μg MC-LReq.kg–1 BW）的方法，用HPLC–MS首次测定了微囊藻毒素在暖水性浮游植物食性鳙鱼的各个组织器官分布情况。MC含量在肾脏中最高（0.094 - 4.641 μg g-1 DW），其次是胆囊（0.328 – 2.474 μg g-1 DW）、肠道（0.014 – 0.751 μg g-1 DW）、肌肉（0.008 – 0.106 μg g-1 DW）和脾脏（0 – 0.017 μg g-1 DW）。
|英文摘要: ||Microcystins are a kind of hepatotoxic cyanotoxin. This study mainly contains two parts, ecology and toxicology of microcystins.
The first part is a field survey of microcystins in Lake Xingyun, a subtropical plateau lake in China. Seasonal variations of dissolved MC, MC in seston and algal blooms were studied, and the effects of physico-chemical and biological factors on MC dynamics were discussed to evaluate on the possible mechanisms underlying these variations. The results were summarized as follows:
1. Correlation analysis suggested that the production of Microcystis in Lake Xingyun was correlated with N content (such as TN and TDN) and optimum temperature (between 20 and 25℃).
2. Significant linear relationship between total MC (dissolved MC + MC in seston) and the product of MC in algal blooms and Microcystis biomass suggested that MC concentration is regulated by both the biomass of toxin-producing phytoplankton in the water column and the concentration of MC produced per unit mass of these phytoplankton, and that factors affecting MC production are not necessarily the same with those affecting the biomass of the toxin-producing phytoplankton.
3. In Lake Xingyun, the maximum MC concentration reached as high as 42.12 µg l-1 during the warm season and was considerably higher than those of Microcystis blooms in other regions of the world. It is urgently needed to monitor MC pollution in Lake Xingyun and to reduce the exposure risk of cyanobacterial toxins to both aquatic animals and human beings.
The second part is a laboratory study on tissue distribution and deputation of microcystins in bighead carp via intraperitoneal injection. The possible mechanisms underlying these patterns in comparison with other fishes of different feeding modes were also discussed. The results were summarized as follows:
1. This is the first to report MC contents (by HPLC–MS) in various organs of warm–water planktivorous bighead carp via intraperitoneal injection with two different doses, 200 and 500 μg MC-LReq.kg-1 BW. The highest level of MC was found in the kidney (0.094 - 4.641 μg g-1 DW), followed by the gallbladder (0.328 – 2.474 μg g-1 DW), intestine (0.014 – 0.751 μg g-1 DW), muscle (0.008 - 0.106 μg g-1 DW) and spleen (0 - 0.017 μg g-1 DW).
2. Our results suggested that the clearance of MC in gallbladder seems more difficult than other organs and kidney may have capacity to transport microcystin. Most MC-LR but a small quantity of MC-RR in the aquaria water and rather low MC-LR content in the intestine and other organs indicated that the intestine of bighead carp can severely inhibit the transportation of MC-LR. It seems that elimination of MC-LR likely occurred at the intestine while MC-RR degraded in the liver after entering the blood system.|
|Appears in Collections:||中科院水生所知识产出（2009年前）_学位论文|
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