渗透胁迫对杜氏盐藻胞内甘油含量及相关酶活性影响

杜氏盐藻(Dunaliella salina)是一种抗渗透能力强的单细胞绿藻, 甘油在其渗透调节过程中发挥重要作用。本实验对5种不同NaCl浓度条件下, 盐藻的生长、细胞内甘油含量及甘油代谢相关酶的活性变化进行了测定。结果表明, NaCl浓度过高或过低均影响盐藻的生长; 高渗胁迫条件下甘油含量迅速增加,3-磷酸甘油磷酸酶的活性和二羟丙酮还原酶催化二羟丙酮转化为甘油的活性明显增加; 而低渗胁迫条件下的甘油含量会迅速降低, 3-磷酸甘油磷酸酶的活性丧失, 二羟丙酮还原酶催化甘油转化为二羟丙酮的活性增加。基于此实验结果, 我们对盐藻渗透胁迫条件下细胞内的甘油代谢过程与其抗渗透胁迫能力的相关性进行了探讨。

Effects of Osmotic Stress on Intracellular Glycerol Content and Enzyme Activity in Dunaliella salina

Dunaliella salina is known as probably the most halotolerant eukaryotic organism living in various salt habitats, and glycerol metabolism plays an important role in its osmoregulation. We investigated the growth, intracellular glycerol content and activities of enzymes in glycerol metabolism under NaCl stress. Growth of D. salina was inhibited in solutions containing 4.0, 3.0, 0.8, and 0.6 mol.L-1 NaCl. The intracellular glycerol content accumulated and activities of glycerol 3-phosphate phosphatase and dihydroxyacetone reductase catalyzing dihydroxyacetone to glycerol were enhanced in response to hyperosmotic stress. However, glycerol content decreased and the activities of glycerol 3-phosphate phosphatase lost and dihydroxyacetone reductase catalyzing glycerol to dihydroxyacetone increased when adapting to hypo-osmotic stress. The paper discusses the association of glycerol metabolism with the osmoregulation mechanism of D. salina.