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题名: 砷对微囊藻生长影响及其形态转化研究
作者: 王畅
答辩日期: 2008-06-13
导师: 刘剑彤
授予单位: 中国科学院水生生物研究所
授予地点: 水生生物研究所
学位: 硕士
关键词: 微囊藻 ; 砷酸盐 ; 磷酸盐 ; 细胞密度 ; 形态分析
其他题名: The Study on the Influence of Arsenic on the Growth of Microcystis aeruginosa and the Arsenic Speciation Transformation
摘要: 本文采用微囊藻Microcystis aeruginosa 905和砷酸盐作为研究对象,分析砷对微囊藻生长的影响以及探讨由于微囊藻对砷胁迫的响应致使砷形态的变化。采用显微镜进行细胞计数研究砷对微囊藻生长的影响,采用HPLC-HG-AFS检测微囊藻胞外培养基中砷的形态考察微囊藻对砷胁迫的响应。微囊藻胞外培养基基体复杂,在砷形态分析中采用基体匹配法消除基体干扰。 研究分析结果如下: (1) 微囊藻胞内胞外缺磷条件下,砷对微囊藻毒性较强、致毒作用较快,并且砷对微囊藻毒性随砷酸盐浓度升高明显增强,随微囊藻生物量变大稍微减弱。此条件下砷采用Pit机制进入微囊藻胞内,微囊藻细胞迅速吸收大量砷酸盐并还原为亚砷酸盐,但甲基化过程慢,且MMA是甲基化过程的中间产物,最终胞外检测到As(III)、DMA、As(V)。 (2) 在低磷浓度、中等磷浓度和高磷浓度条件下,砷对微囊藻毒性都不明显、致毒缓慢,砷对微囊藻毒性随砷酸盐浓度升高稍有增强,随微囊藻生物量变大而减弱。这些磷条件下,砷均采用Pst机制进入微囊藻胞内,微囊藻细胞吸收砷酸盐缓慢,还原得到的亚砷酸盐可完全甲基化为最终产物DMA,所以胞外仅检测到DMA、As(V)。但在高磷、高砷条件下,砷进入胞内虽然缓慢但量大,所以还原而来的亚砷酸盐不能完全甲基化排出胞外,胞外检测到As(III)、DMA、As(V)。 (3) 砷对微囊藻生长影响在微囊藻生长规律中的迟滞期时效果最明显。其原因是在迟滞期微囊藻代谢活跃并且酶活性强,对砷酸盐吸收和还原速度快,产生毒性明显。 总之,在不同磷酸盐浓度条件下,砷对微囊藻生长影响及其形态转化的研究结果表明:磷酸盐浓度控制砷进入微囊藻胞内采用的机制,从而决定砷对微囊藻生长影响和砷的形态转化。并且就微囊藻对砷的生物转化这方面而言,在低磷和中磷条件(与环境供磷水平相当)下,微囊藻将高毒性无机砷转化为低毒性有机砷,砷和微囊藻作用对环境不会产生扩大性危害。
英文摘要: In this research, Microcystis aeruginosa 905 and arsenate were used to investigate the influence of arsenic on Microcystis aeruginosa and the arsenic speciation transformation. Cell density was observed by microscope in order to investigate the toxicity of the arsenate to the Microcystis aeruginosa. The speciation analysis method of HPLC-HG-AFS was applied to determinate the biotransformation of the Microcystis aeruginosa to the arsenate. The matched matrix was used in the speciation analysis method to eliminate the matrix effects of the algae broth. The main results were summarized as follows: (1) When intracellular and extracellular phosphorus of the Microcystis aeruginosa was absent, the effect of toxicity caused by the arsenate to the Microcystis aeruginosa was strong and rapid. The toxicity was enhanced evidently along with the increase of arsenate concentration and was reduced unobviously along with the increase of Microcystis aeruginosa biomass. When the arsenate entered into the cell by Pit system, it was deoxidized to arsenite rapidly, and then the arsenite was methylated toMMA and DMA slowly. MMA was the intermediate product, so As(III)、DMA、As(V) were found in the Microcystis aeruginosa broth finally. (2) Under the conditions of low, moderate and high phosphorus concentration, the effect of toxicity caused by the arsenate to the Microcystis aeruginosa was weak and slow. The toxicity was enhanced unobviously upon the increase of arsenate concentration and reduced with the increase of Microcystis aeruginosa biomass. Here, the arsenate entered into the cell by Pst system and was deoxidized to arsenite that was methylated completely to DMA slowly, and only DMA、As(V) were found in the Microcystis aeruginosa broth. However, As(III)、DMA、As(V) were found under high phosphorus and arsenate concentration because large number of arsenate was deoxidized to arsenite which couldn’t be methylated completely. (3) The influence of arsenate to Microcystis aeruginosa was affected by biological growth manner. It was the most obvious in the lag phase that the effect of arsenate to the Microcystis aeruginosa. The reasons were that the metabolism of Microcystis aeruginosa.was promoted and enzyme was high, and the adsorption and reduction of arsenate was rapid, which induced evident toxicity. In conclusions, the entrance system of arsenate into the Microcystis aeruginosa was controlled by phosphate concentration, which decided the influence of the arsenate on growth of the Microcystis aeruginosa and the arsenic speciation transformation. Under low and moderate phosphorus concentration of broth that was equivalent to phosphorus of environment, the arsenate was translated into low toxic arsenic speciation. It was worth noting that the harm to the circumstance induced by the biotransformation of the Microcystis aeruginosa to the arsenate can not be enlarged.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.ihb.ac.cn/handle/342005/12374
Appears in Collections:中科院水生所知识产出(2009年前)_学位论文

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Recommended Citation:
砷对微囊藻生长影响及其形态转化研究.王畅[d].中国科学院水生生物研究所,2008.20-25
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