三价铬对酵母细胞脂肪酸摄取和三酰甘油合成的影响

Effects of trivalent chromium on fatty acid uptake and triacylglycerol synthesis in Saccharomyces cerevisiae

为探究三价铬离子对酵母细胞脂质代谢的影响及其作用机制,通过油红O染色和薄层层析检测酵母总脂质及脂肪酸和三酰甘油含量,倒置荧光显微镜观察酵母细胞内脂滴数量以及GC-MS分析酵母细胞内脂肪酸组分,观察三价铬离子对酵母脂质含量的影响。实时定量PCR进一步检测酵母脂质代谢相关基因的转录,分析酵母脂质含量变化的机制。选取SMMC-7721细胞对三价铬离子的降脂作用进行功能保守性验证。结果表明:100μmol/L三价铬离子处理后,酵母内总脂质及脂肪酸和三酰甘油的含量降低,细胞内脂滴数量减少,脂肪酸组成比例得到调节;细胞内脂肪酸摄取基因FAA1、FAA3和三酰甘油合成基因DGA1、PAH1的转录水平呈下调。三价铬离子同样引起SMMC-7721细胞脂质含量降低和脂肪酸摄取基因ACSL1、ACSL3和三酰甘油合成基因DGAT2的转录水平下调。研究表明,三价铬通过降低脂肪酸摄取基因和三酰甘油合成基因的表达,降低细胞对油酸的摄取和三酰甘油的合成,从而调节细胞内脂质含量。

To study the effect and mechanism of trivalent chromium on lipid metabolism in saccharomyces cerevisiae,total lipid,fatty acids,and triacylglycerol content in yeast were detected by oil red O staining and thin layer chromatography.The number of lipid droplets in yeast cells was observed by inverted fluorescence microscopy,and the fatty acid composition in yeast cells was analyzed by GC-MS.The effect of trivalent chromium on yeast lipid content was observed.Real time quantitative PCR further detected the transcription of genes related to yeast lipid metabolism and analyzed the mechanism of changes in yeast lipid content.Finally,the functional conservation was verified in SMMC-7721 cells.The results indicated that when treated with 100μmol/L trivalent chromium,the contents of total lipids,fatty acids and triacylglycerol were reduced,the number of lipid droplets was decreased in cells,and the composition of fatty acids was regulated in yeast cells.The transcription of fatty acid uptake genes FAA1 and FAA3 and triacylglycerol synthesis genes DGA1 and PAH1 was significantly down-regulated by trivalent chromium in yeast cells.The lipid content and transcription of fatty acid uptake genes ACSL1,ACSL3 and triglyceride synthesis gene DGAT2 was also reduced by trivalent chromium in SMMC-7721 cells.It is implied that trivalent chromium might control the lipid reduction by regulating the genes expressions involved in fatty acid uptake and triacylglycerol synthesis.