盐生杜氏藻的完整叶绿体分离

盐生杜氏藻(Dunaliella salina)是世界上最耐盐的一种单细胞真核绿藻，可在含0．1～5．0mol／L NaCl的培养液中正常生长．盐生杜氏藻细胞内的主要调渗物质是甘油，在甘油代谢途径中，3-磷酸甘油脱氢酶是一个关键酶．近年来的研究表明杜氏藻(Dunaliella tertiolecta)细胞质和叶绿体中都存在3-磷酸甘油脱氢酶的同工酶，且叶绿体上的同工酶与渗透调节作用直接相关,为了解D．satina中3-磷酸甘油脱氢酶同工酶的细胞定位和分布，我们通过冰浴超声波破碎和蔗糖密度梯度离心，获得盐生杜氏藻的完整叶绿体，用相差显微镜镜检、酶的活性分析等方法对其完整性作了初步分析。

Isolation of Intact Chloroplasts from Dunaliella salina

Cells of Dunaliella salina from the log phase of growth were broken by sonication on ice-water-bath and the chloroplasts were isolated by centrifugation through sucrose gradient. Osmolarity of the growth medium, the suspending medium and the sucrose gradient was kept identical to minimize changes in chloroplast volume and mitochondrial entrapment. The isolated intact chloroplasts were stable to washing with buffered medium. Isolated chloroplast yield and purity was dependent on cell culture condition; a cycle of 16 hours light and 8 hours dark with continuous high CO_2 was optimum. Isolated chloroplasts were about 70% intact by microscopic examination. The enzyme activity of glycerol-3-phosphate dehydrogenase was well retained in isolated chloroplasts.