动物造模,硅藻油脂积累 z-bo 2020-09-26 373

　　Recently, Hu Hanhua, an associate researcher at the Institute of Hydrobiology, Chinese Academy of Sciences, used the model species Phaeodyylumum tricornutum to study diatoms and how various metabolic pathways produce carbon during the accumulation of diatom oil. It is clear whether to promote the flow of triglycerides and synthesize triglycerides. Diatom is an important group of algae. As the main primary producer, it accounts for about one-fifth of the world's primary production, which is equivalent to the net primary production of the entire tropical rain forest. Unlike most algae, the product of diatom assimilation is mainly oil or chlorophyll, which is most suitable because it is stored in the cell in the form of oil droplets, which can account for 40-60% of its content. It is considered one of the raw materials of biodiesel. However, the molecular mechanism of the reservoir is still unknown.

　　Recently, Hu Hanhua, an associate researcher at the Institute of Hydrobiology, Chinese Academy of Sciences, used diatoms as the target model species Phaeodyylum tricornutum. In the process of diatom oil accumulation, various metabolic pathways are triglycerides. We have clarified how to promote the flow of carbon to synthesis. They first used the subtractive hybridization technique and found that the gene MCC2, which is related to leucine degradation, was significantly up-regulated during the oil accumulation process. Since it is generally believed that the accumulation of oil is accompanied by the limitation of nutrients, the degradation of amino acids is an inevitable result under the conditions of nutrient limitation. But where is the breakdown of amino acids? Are all of these related to fat accumulation? There is no direct evidence for these problems.

　　Fluorescence quantitative PCR and unlabeled quantitative proteomics analysis (cooperation with researcher Ge Feng from the Institute of Aquatic Biology), as well as amino acid degradation, glycolysis, tricarboxylic acid cycle, pyruvate metabolism, fatty acids and participation in triglycerides The level of synthesized protein increased significantly. In the process of oil accumulation, the carbon stream produced by amino acid degradation and cellular glycolysis enters the tricarboxylic acid cycle, and then synthesizes fatty acids through malic acid or directly in the form of pyruvate. Show entry. The functional verification results showed that triglyceride synthesis in MCC2 knockout algae strains was reduced by 28-37%. Studies have shown that under conditions of limited nutrition, up to 40% of the pyramidal fruit lipids are transformed from the decomposition of other components of the cell. Facts have proved that the breakdown of branched chain amino acids, especially the breakdown of leucine, may play a major role in the accumulation of Tritornutumum peanut oil. Analysis of metabolite levels showed that the degradation of three branched chain amino acids in MCC2 knockout algae strains was inhibited to varying degrees. The content of glutamic acid, arginine, glutamic acid, proline, alanine, ornithine and aspartic acid is much higher than the three branched chain amino acids before oil accumulation, but the content of these amino acids quickly. Down to a low level. Experiments have further proved that these amino acids are directly or indirectly related to the unique urea cycle of diatom, which is stored in the cell through the decomposition of the urea cycle before the cell lacks nitrogen, ammonia and nitrogen dioxide. Form carbon or synthetic polyamines. Experiments also show that the degradation of valine is accomplished by first forming leucine. Their experiments showed for the first time that the carbon flow produced by cellular glycolysis and the degradation of branched-chain amino acids caused lipids to accumulate in diatomic cells.