空间飞行对稻田鱼腥藻遗传特性的影响

Effect of Space Flight on Hereditary Characteristics of Anabaena Oryza (Cyanobacteria).

通过对具有高固氮酶活性的稻田鱼腥藻返地克隆株（ＡｏＳＲ１６）的回复再搭载及其返地样品的单克隆实验，发现空间飞行环境能导致该藻株再次出现性状分离现象，即部分单克隆株仍保持高固氮酶活性（如ＡｏＳＲ１６－１７），而另一部分单克隆株则回复到原始出发株（ＡｎａｂａｅｎａｏｒｙｚａＨＢ２３）的固氮酶活性水平。对ＡｏＳＲ１６－１７进行近两年的地面保持培养发现，这种高固氮酶活性的性状是可以遗传的。进一步通过ＲＡＰＤ分析方法，运用１２０个１０核苷酸随机引物对ＡｏＳＲ１６－１７和原始出发株的基因组ＤＮＡ进行多态性研究，结果发现：在扩增出的５００多条带中，有４条带在ＡｏＳＲ１６－１７和原始出发株之间表现出了多态性。这表明。

A retrieved monoclonal strain AoSR16 with high nitrogenase activity was reflown in space onboard a satellite, and characteristics differentiation was found again when the sample was retrieved and isolated in the laboratory.Some isolates still kept their nitrogenase activity on the same level of original strain,while other isolates like AoSR16 17 expressed higher nitrogenase activity . After 2 years of maintaining culture, the activity of nitrogenase in AoSR16 17 remained continuously high. Comparative studies between AoSR16 17 and the original strain were carried out in regard of genetic features. The polymorphism of total genomic DNA in AoSR16 17 and the original strain was studied by RAPD analysis, using 120 10 mer random primers. Of approximately 500 amplified electrophoresis bands, 4 polymorphic fragments were discernible between AoSR16 17 and the original one, the polymorphism was thus calculated to be around 0.08%. These four bands had been purified and further work is under way.