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摘 要：铬是一种重金属，一般以金属铬、三价铬和751价铬三种形式存在，它们均有毒性。在自然状态下仅存在后两种形式，而且751价铬的毒性最大。因铬具有很高的耐腐蚀性，常被用于电镀、金属加工、制革等行业，因此排出的废气和废水是环境中的主要污染源。其中，毒性最大的751价铬为吸入性极毒物，皮肤及黏膜接触可导致过敏，造成基因突变和遗传缺陷，而且致癌，通过食物链的传递还会出现富集效应，对生物和环境危害极大。在水污染、大气污染愈来愈严重的今天，实时监测环境中各种重金属等污染物的浓度，研究典型生物对重金属胁迫的生理响应及分子机制，通过物理化学或生物吸附的方法减少重金属含量及其毒性效应，是亟待解决的问题。集胞藻6803是一种淡水生单细胞蓝藻，因其个体微小、对各种胁迫响应迅速、环境适应性强、基因组已知、便于进行遗传操作和生理指标测定等特点，是研究胁迫响应的理想材料。本研究以集胞藻6803为材料，研究了不同浓度的751价铬处理对藻细胞生长的影响。结果表明：Cr6+处理对集胞藻6803的生长及光合色素含量、蛋白质图谱等有不同程度的影响。10µM的Cr6+对集胞藻6803的生长影响不大，但藻细胞中的叶绿素含量、类胡萝卜素含量均显著降低；30µM的Cr6+则严重影响集胞藻6803的生长，细胞培养物颜色变黄，光合色素的含量急剧减少。但这两个浓度的Cr6+对细胞全蛋白的表达谱均没有显著影响。32814
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毕业论文关键词：集胞藻6803；Cr6+；生长；光合色素；蛋白图谱
Effects of hexavalent chromium on the growth of Synechocystis sp. PCC6803
Abstract: Chromium is one of the heavy metal elements which can exists in three forms: chrome metal, trivalent chromium and hexavalent chromium, and all of them are toxic. There are only the latter two forms of chromium in natural environment, while hexavalent chromium possesses the maximum toxicity. Due to the strong corrosion resistance, chromium was widely applied in electroplate, metalworking, the tanning industry, with massive emission of exhaust gas and waste water into environment. While, hexavalent chromium is an inhaled toxic substance, skin exposure and mucosal contact might cause allergy, gene mutation, genetic defect, and may cause cancer. It could also be enriched when passing through the food chain, resulting in great harm to environment and living organisms. Nowadays, the conditions of air and water pollution are growing worse, and these subjects are urgently to be solved, for instance, monitoring the situation of heavy metal pollution in the water, study on the effects and molecular mechanism of heavy metal on the growth of typical organisms, reducing the content and alleviating the toxic effects of heavy metals by means of physicochemical and biological adsorption. Synechocystis sp. PCC6803 is one of the unicellular limnetic cyanobacteria which possess numerous advantages: small inpiduals, quick response to various stresses, well-adapted to a variety of environments，available genomics and convenient for genetic manipulation, and these characteristics make Synechocystis one of the model organisms in study of stress responses. In the present research, effect of different concentration of hexavalent chromium on the growth of Synechocystis sp. PCC6803 was studied. The results showed that hexavalent chromium treatment differently impacts the growth, photosynthetic pigments contents as well as the protein profiles of Synechocystis cells. Specifically, when cells were cultured in the medium containing 10µM Cr6+, the growth curve was comparative to the control, although the contents of chlorophyll and carotenoid were remarkably reduced. While, 30µM Cr6+ treatment had a strong impact on growth, cell culture showed abnormal yellow color, and the content of photosynthetic pigments declined seriously. Nevertheless, neither of the treatment affects the protein profiles of total proteins in cells.