缺刻缘绿藻的光合膜脂与中性脂及其脂肪酸组成在氮饥饿/氮恢复培养过程中的变化  

Alternations of photosynthetic membrane lipids and triacylglycerol and their fatty acids in Myrmecia incisa grown in a shift from nitrogen starvation to replenishment

作　　者：欧阳珑玲[1] 李晓蕾[1] 周志刚[1] OUYANG Long-ling LI Xiao-lei ZHOU Zhi-gang(College of Fisheries and Life Science, SJ~anghai Ocean University, Shanghai 201306, China)

机构地区：[1]上海海洋大学水产与生命学院,上海201306

出　　处：《海洋渔业》2016年第6期653-662,共10页Marine Fisheries

基　　金：国家自然科学基金项目(31402274;31172389);中国博士后科学基金项目(2014M551381);国家海洋局可再生能源专项基金(SHME2011SW02)

摘　　要：对缺刻缘绿藻(Myrmecia incisa)进行氮饥饿(4 d)/氮恢复(4 d和8 d)培养,研究其细胞中三酰甘油(TAG)和光合膜脂,主要是单半乳糖二酰甘油(MGDG)和二半乳糖二酰甘油(DGDG)的含量和脂肪酸组成的变化。结果表明TAG含量在氮饥饿胁迫下显著上升,而在氮恢复培养下逐渐下降;DGDG含量的变化趋势与TAG相反;MGDG的含量则始终呈现上升趋势。对脂肪酸组成进行分析发现花生四烯酸(ArA)主要存在于TAG中,且TAG中ArA的含量在氮饥饿胁迫下显著上升,并在氮恢复培养下逐渐下降。DGDG中ArA含量在氮饥饿/氮恢复过程中的变化与TAG中的相反;MGDG中ArA的含量在不同培养条件下始终增加。该结果表明在氮饥饿胁迫下DGDG可能向TAG合成提供ArA,而TAG在氮恢复后可向光合膜脂提供脂肪酸以供其合成。Myrmecia incisa H4301, a coccoid microalga, is a member of Trebouxiophyceae, Chlorophyta, which usually aggregates together to form non-coenobium populations. It has been found an arachidonic acid （ArA, 20： 4co6）-rich species, particularly during nitrogen starvation. Under this condition for 27 d, its ArA content increased to 7.0% of dry weight （DW） biomass. In addition, 76% of intercellular ArA is accumulated in the form of neutral lipids, which increases one fold in this alga while grows under nitrogen starvation. Therefore, this species might be one of the ideal and potential commercial sources for ArA. In addition, both the number and volume of triacylglycerol （TAG） -rich oil bodies significantly increases with the shrink of chloroplasts after cultivation under nitrogen starvation. These suggest that there is increasing TAG synthesis with a loss of photosynthetic membrane lipids when M. incisa is cultured under this condition. However, the accurate pathway of TAG biosynthesis in this microalga is unknown. This study aims to explore the effects of nitrogen starvation/replenishment on the content and fatty acid composition of photosynthetic membrane lipids, mainly monogalactosyldiacylglycerol （MGDG） and digalactosyldiacylglycerol （DGDG）, and TAG in M. incisa. It will not only enable us to give a deep insight into the biosynthesis pathway of TAG accumulation under nitrogen starvation and the degradation of TAG to help reconstruct chloroplastic membrane under the following suitable environment, but also lay a foundation for the enhancement of TAG and ArA content of biofuel produced microalgae. By using thin layer chromatography （TLC） combined with gas chromatography-mass spectrum （GC- MS）, the content of MGDG, DGDG and TAG in M. incisa under nitrogen starvation/replenishment were analyzed. Results showed that the amount of TAG dramatically increased during nitrogen starvation. The maximum value appeared on the fourth day, which was 2.1 times that on day 0 （P 〈 0.05 ）. From the

关 键 词：缺刻缘绿藻 氮饥饿 氮恢复 单半乳糖二酰甘油(MGDG) 二半乳糖二酰甘油(DGDG) 三酰甘油(TAG) 花生四烯酸(ArA) 

分 类 号：Q547[生物学—生物化学]