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| 发菜类囊体膜的组成及其光合特性的研究 | |
| 王梅 | |
| 出版年 | 1999 |
| 学位类型 | 博士 |
| 导师 | 匡廷云 |
| 学位授予单位 | 中国科学院植物研究所 |
| 中文摘要 | 发菜（Nostoc flagelliforme Born. et Flah.）的细胞壁由纤维素、半纤维素、糖脂和蛋白质组成。未经破碎的细胞难以进行各种光合特性的研究。由于纯度较高的发菜类囊体膜制备比较困难，对它的光合机理的研究一直是停留在整体水平上进行。我们采用French Press低温下高压破碎细胞，建立了一种快速简便的制备方法。在提取液中加入一定浓度的Ca~(2+) （Ca~(2+)既有助于维持类囊体膜的放氧活性又可以使类囊体膜在较低的离心速度下使类囊体膜得到凝集沉淀），从而在较短时间内、在高速离心的情况下得到了纯度较高并具有较高放氧活性的发菜类囊体膜。在此基础上，我们采用改进的Allen（1991）的温和绿胶系统，首次对陆生蓝藻发菜类囊体膜色素蛋白复合体进行了分离，共分离出了11条绿色的色素蛋白复合物条带和两条浅黄色的条带。7条绿色的色素蛋白复合物条带属于PSI组分，4条绿色的蛋白复合物条带属于PSII组分，其中一条浅黄色条带系未被报道过的新的色素蛋白复合物条带，经其光谱性质的分析初步鉴定为类胡萝卜素蛋白复合物，此复合物的分离有助于解释发菜独特的适应荒漠、半荒漠地带高光辐射的特性。本文还对干燥状态、复水30分钟后和复水生长24小时后的野生发菜及人工培养的发菜藻丝体膜脂及其脂肪酸组成进行了分析。发菜的膜脂由MGDG、MGDG、SQDG和PG组成，其酯酰基部位连接有16:0、16:1、18:0、18:1、18:2和18:3六种脂肪酸。野生发菜中具有高含量的不饱和脂肪酸，其含量可达总脂的73%，其中16:1和18:3分别达到28.9mol%和34.3mol%，远远高于已报道的其它蓝藻，所以我们推测发菜具有极强的抗逆性和其膜脂不饱和程度密切相关。分析不同处理的发菜的膜脂和脂肪酸组成表明，复水对野生发菜的膜脂及其脂肪酸组成没有显著影响，说明发菜的膜脂和脂肪酸组成在干燥状态下能保持很高的稳定性。从野生发菜分离出的藻丝体在25 ℃条件下培养，其膜脂脂肪酸组成发生了显著变化，主要表现为脂肪酸的不饱和程度的大幅度降低，18:3从34.9mol%降低到8.6mol%，16:1从28.9mol%降低到13.9mol%。上述结果表明了发菜具有极强的通过改变其膜脂的脂肪酸组成而适应生存环境的能力。 |
| 英文摘要 | The cell wall of Nostoc flagelliforme Born. et Flah. is composed of cellulous, semi-cellulous, glycolipid and proteins. It is difficult for us to investigate its photosynthetic properties without breaking the cells. Since it is difficult to purify thylakoid membrane from Nostoc flagelliforme, researchers have been doing photosynthetic research with intact cells. We used the French Press (USA) to purify the thylakoid membrane from Nostoc flagelliforme successfully. The purification procedure described in this paper is quite simple. Addition of CaCl_2 helps to maintain oxygen activity and aggregate the membranes so that they can be conveniently pelleted in a short time by normal centrifugation instead of ultracentrifugation. By using Allen' method improved by us, we seperated 11 green bands and two yellow bands from Nostoc flagelliforme thylakoid membrane. Seven of the green bands represent photosystem I, the remaining four green bands represent photosystem II. This method has also proved useful for isolation of carotenoid-blinding proteins. One of the two yellow bands was isolated for the first time and was thought to be carotenoid-binding protein complex. This protein complex may help to explain the reason why Nostoc Flagelliforme has high resistance in desert and semi-desert conditions. Further work is going on. The composition of membrane lipids and their fatty acids of disccated wild Nostoc flagelliforme, Nostoc flagelliforme tested 30 minutes after being allowed to absorb water and Nostoc flagelliforme allowed to absorb water and then cultured for 24 hours, were investigated. The membrane lipids of Nostoc flagelliforme are composed of MGDG, DGDG, SQDG and PG. There are six kinds of fatty acids, 16:0, 16:1, 18:0, 18:1, 18:2 and 18:3, attached to the carboxylic site of the membrane lipids. The concentration of unsaturated fatty acid of wild Nostoc flagelliforme is much higher than that of the other cyanobacteria reported so far, it is as high as 85% of the total amount of the fatty acids, among which 16:1 and 18:3 are as high as 28.9% and 34.3% respectively. The high resistance of Nostoc flagelliforme to abnormal conditions may be associated with its degree of unsaturation of fatty acids. The three different samples of Nostoc flagelliforme exhibit small variation in their composition of membrane lipids and their fatty acids, which means that water-absorption has no effect on the composition of membrane lipids and their fatty acids of Nostoc flagelliforme. Results of the Nostoc flagelliforme isolated from the wild Nostoc flagelliforme cultured at 25 degree calcius show that its composition of membrane lipids and their fatty acids changed greatly. The degree of unsaturation of fatty acid decreased dramatically, for example, 18:3 and 16:1 decreased to 8.6% and 13.9% respectively. The above results imply that Nostoc flagelliforme has a high ability to adapt to its environment through changing its composition of fatty acids of membrane lipids. |
| 中文关键词 | 发菜 ; 类囊体膜 ; 色素蛋白复合物 ; 绿胶 ; 膜脂 ; 不饱和脂酸 |
| 英文关键词 | PSI PSII Nostoc flagelliforme Born. et Flah. thylakoid membrane chlorophyll-protein complex green gel lipid unsaturation fatty acid |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源机构 | 中国科学院植物研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286242 |
| 推荐引用方式 GB/T 7714 | 王梅. 发菜类囊体膜的组成及其光合特性的研究[D]. 中国科学院植物研究所,1999. |
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