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几种微藻的空间生物学效应及其分子机制
胡章立
Subtype博士
Thesis Advisor刘永定 ; 俞敏娟
1997
Degree Grantor中国科学院水生生物研究所
Place of Conferral中国科学院水生生物研究所
Degree Discipline水生生物学
Keyword稻田鱼腥藻 盐生杜氏藻 空间环境 微重力 适应 性状分离 细胞质膜
Abstract本研究利用返回式科学实验卫星对9种微藻进行了空间搭载试验。通过对返地样品的进一步分析,发现藻类对空间飞行环境具有很强的适应能力。这种适应主要表现在两个方面:①在搭载的藻类材料中,绝大多数都能在空间环境中生存与生长,并且一些种类在空间环境中表现出生长增强效应,固定化藻细胞较液体培养及固体Agar培养的藻细胞表现得更为明显。②在对稻田鱼腥藻的空间搭载及再搭载实验中,发现了高固氮酶活性变异株—AoSR16和AoSR16-17,它们是空间效应的适应性表现形式。将具有高固氮酶活性的空间返地单克隆株(AoSR16)进行空间回复搭载,并对返地样品进行单克隆分离,结果再次出现了性状分离现象,即一些克隆株回复到出发株的固氮酶活性水平,一些则保持高固氮酶活性(如 AoSR16-17)。对高固氮酶活性单克隆株进行近两年的保持培养后,有的克隆株(如 AoSR16-17,AoSR16-47 等)继续保持高固氮酶活性,而有的克隆株(如 AoSR16-32等)则恢复到出发株的固氮酶水平。对AoSR16-17与初始出发株(Original strain)进行了包括形态结构、生理生化及遗传特性的比较分析,结果表明:AoSR16-17的藻丝体相对较长,细胞壁较薄,脂质体数目减小;氮代谢活性与代谢途径及其储藏物和分泌物的情况均发现了变化。高固氮酶活性变异株固定的氮在地面培养时除用于正常生长外,同时以藻胆蛋白累积和以氨的形式处排;而在微重力环境中则主要用于促进生长。运用120个10个核苷酸随机引物的RAPD分析,对AoSR16-17和初始出发株的基因组DNA进行了多态性研究,发现在扩增出的500多条带中,有4条带在AoSR16-17和初始出发株之间表现出多态性。回收4条差异带,用凝胶PCR扩增,再经DNA纯化系统分离,得到了纯的差异带,对基进一步的分析正在进行中。通过回转器模拟微重力刺激实验,发现在微重力刺激下,杜氏盐藻细胞甘油含量增加,H~+分泌速率加快,膜磷脂与膜蛋白比率下降,质膜(PM)H~+-ATPase活性升高。并在此基础上进一步通过抑制剂与激活剂实验及其分析结果,构建了藻类对微重力刺激感受、传导与中央委员应的初步模型。结果表明:细胞质膜是盐生杜氏藻细胞主要微重力感受体;膜磷脂/蛋白、PM H~+-ATPase、膜电位、Ca~(2+)及钙调蛋白在其信号传导与响应过程中起到重要的作用。
Other AbstractNine species of algae had been flighted in space for eight days and they were then retrieved and analyzed in laboratory. The results indicated that the algae had a strong adaptability to space environment, their adaptability mainly displayed in the following two environment, their adaptability mainly displayed in the following two aspects: ① most of the flighted algae could survive and grow in space, stimulation of the growth were observed in some algae, especially in immobilized algal cells ② Space adaptable strains(AoSR16 and AoSR16-17 etc.) had been isolated from the samples of space flight or re-flight Anabaena oryza HB23. The monoclonal strain AoSR16 of high nitrogenase activity was re-flighted in space by satellite, and characteristics differentiation was found again when the sample was retrieved and isolated in laboratory. While some isolates still kept their nitrogenase activity on the same level of original strain, other isolates like AoSR16-17 expressed higher nitrogenase activity. After 2 years in maintaining culture, the activity continuously remained high in strains like AoSR16-17, AoSR16-47, but in strains like AoSR16-32 its nitrogenase activity dropped back to the level of the original strain. Comparative studies on AoSR16-17 and the original strain were carried out in regard of morphological, physiological, biochemical and genetic features. Compared with the original strain, AoSR16-17 had longer filaments, thinner cell wall and less lipid bodies, furthermore its nitrogen activity and nitrogen metabolism path changed obviously. At the ground culture condition, the fixed nitrogen not only served as growth nutrition, it can also be restored in the form of phycobiliprotein or excreted as ammonium. On the other hand, the nitrogen was mainly used to enhance the growth under microgravity condition. The polymorphism of total genomic DNA between AoSR16-17 and Original strain were studied by RAPD analysis, using 120 10-mer random primers. Of approximate 500 amplified electrophoresis bands, 4 polymorphic fragments were discernible between AoSR16-17 and the original, the polymorphism was thus calculated around 0.08 %. These four bands had been purified and further work is under way. Clinorotation experiments was established to simulate microgravity in ground condition. During clinorotation, correlation between simulating microgravity and some physiological and biochemical parameters had been observed in the unicellular Dunaliella salina. The changes included the increase of glycerol content, the rate of H~+ secretion and PM H~+-ATPase activity, and the decrease of the ratio of the plasma membrane(PM) phospholipid to PM protein. Based on these results and the data obtained by using activators and inhibitors, a preliminary model was proposed to explain how the alga cell gravi-sense, transduct and response to the microgravity. In this model, PM is quite possible the sensing body of microgravity, other factors, such as PM H~+-ATPase. PM phospholipid /protein, PM electrical potential, Ca~(2+) and calmodulin, may play important roles in signal transduction and response.
Pages126
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/12512
Collection学位论文
Recommended Citation
GB/T 7714
胡章立. 几种微藻的空间生物学效应及其分子机制[D]. 中国科学院水生生物研究所. 中国科学院水生生物研究所,1997.
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