Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
FEBS Lett. 2013 Feb 14;587(4):370-7. doi: 10.1016/j.febslet.2012.12.020. Epub 2013 Jan 10.
Phenotypic and genotypic changes in Chlamydomonas reinhardtii BafJ5, a starchless mutant, with respect to lipid metabolism was studied in different trophic states under nitrogen (N) sufficient and limited conditions. Interestingly, cellular lipid content increased linearly with input acetate concentration with highest lipid content (∼42%) under nitrogen limitation and mixotrophic state. RT-qPCR studies indicate that key fatty acid biosynthesis genes are down-regulated under N limitation but not under mixotrophic state, whereas, ACS2, encoding Acetyl-CoA synthetase, and DGTT4, encoding Diacylglycerol O-acyltransferase, are up-regulated under all conditions. These results collectively indicate that acetate is the limiting factor and central molecule in lipid droplet synthesis. The study also provides further evidence of the presence of a chloroplast pathway for triacylglycerol synthesis in microalgae.
以氮素充足和限制条件下不同营养型为背景，研究了莱茵衣藻 BafJ5 突变体（一种不含淀粉的突变体）的表型和基因型在脂代谢方面的变化。有趣的是，细胞内脂含量随添加的醋酸盐浓度呈线性增加，在氮素限制和混合营养型条件下，脂含量最高（约 42%）。RT-qPCR 研究表明，关键脂肪酸生物合成基因在氮素限制下下调，但在混合营养型条件下不下调，而编码乙酰辅酶 A 合成酶的 ACS2 和编码二酰基甘油 O-酰基转移酶的 DGTT4 在所有条件下都上调。这些结果共同表明，醋酸盐是脂质滴合成的限制因素和中心分子。该研究还进一步证明了在微藻中存在用于三酰基甘油合成的叶绿体途径。
