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Regulation of Gene Expression of Fatty Acid Synthetase in Euglena

裸藻脂肪酸合成酶基因表达调控

基本信息

批准号：
63480491
负责人：
KAWAGUCHI Akihiko
金额：
$ 4.29万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

项目摘要

Fatty acid synthetase (Type 1) was purified from a mutant of Euglena gracilis which is defective in the function of chloroplasts. Purification was carried out by ammonium sulfate and hydroxyapatite treatments. This fatty acid synthetase was not stable and its activity was lost during the purification. Several reagents tested did not prevent the lost of the activity.We investigated the effects of CO_2 concentration during growth on the lipid metabolism in Chlorella vulgaris 11h. Major lipids of C. vulgaris was phosphatidylcholine (PC), phosphatidylethanolamine (PE), monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). The relative contents of lipid classes were essentially the same in high-CO_2 and low-CO_2 cells. However, the degree of unsaturation of fatty acids was higher in low-CO_2 cells than in high-CO_2 cells. The change in the ratio of 18 : 2 to 18 : 3 was particularly significant. The ratio of 18 : 2/18 : 3 in four major lipids was different between high-CO_2 and low-CO_2 cells. The relative differences were markedly greater in galactolipids than in phospholipids. In C. vulgaris, the desaturation of fatty acids bound to MGDG and DGDG occurs in chloroplasts and that of fatty acids bound to PC and PE occurs in endoplasmic reticulum. The former activity was affected by CO_2 concentration more remarkably than the latter activity. It is also suggested that the contributions of chloroplastic and cytoplasmic pathways were different between high-CO_2 and low-CO_2 cells.

从一株叶绿体功能缺陷的细小裸藻突变株中分离纯化出脂肪酸合成酶(1型)。用硫酸铵和羟基磷灰石处理进行提纯。该脂肪酸合酶不稳定，在纯化过程中失去活性。我们研究了生长过程中CO2浓度对普通小球藻11h脂代谢的影响。其主要脂类为磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、单半乳糖二酰甘油(MGDG)和双乳糖二甘油(DGDG)。高CO_2和低CO_2细胞的脂类相对含量基本相同。然而，低CO2细胞的脂肪酸不饱和度高于高CO2细胞。18：2到18：3的比例变化尤为显著。高CO_2和低CO_2细胞四种主要脂类中18：2/18：3的比例不同。半乳糖脂的相对差异明显大于磷脂。在普通球藻中，与MGDG和DGDG结合的脂肪酸的去饱和发生在叶绿体中，而与PC和PE结合的脂肪酸的去饱和发生在内质网中。前者活性受CO_2浓度的影响比后者更为显著。高CO_2和低CO_2细胞的叶绿体途径和细胞质途径的贡献也不同。