随着生物技术的发展和不断完善,许多研究者试图通过生物技术的方法来获得雄性 不育。如 Mariani等, Koltunow等,Li等分别将白喉毒素和两个不同的核糖核酸 酶( Rnase T1和 Barnase)基因进行融合,通过含抗除草剂基因的植物双元表达载体转 化烟草,得到转基因雄性不育烟草和油菜再如 Schmulling等将农杆菌 Rhizogenes A的T-DNA间的rolc基因与CaMV35s启动子串联成嵌合基因转化烟草,结果rolc基因 在转基因植株中的系统表达,出现雄性不育植株

第一节 概 述 第二节 药物代谢的酶( E n z y m e s f o r D r u g M e t a bo lism) 第三节 第Ⅰ相的生物转化(PhaseⅠ B iotransformation)

Introduction: Weathering The Breakdown of Rock At the Earth's surface, rocks are exposed to the effects of weathering: the chemical alteration and mechanical breakdown of rock, when exposed to air, moisture, and organic matter. Weathering is an integral part of the rock cycle. Weathering converts rock to regolith

Introduction: What Is an Igneous rock? Igneous rocks vary greatly. Some contain large mineral grains. Others contain grains so small they can barely be seen under a high power microscope. Igneous rocks also vary greatly in color. All igneous rocks are formed through the cooling and solidification of magma

Earth's Internal Structure When a meteorite impacts a planet or moon, its energy of motion (called kinetic energy)is transformed into heat energy. As Earth grew larger and larger from continual impacts, its temperature increased. Radioactive decay of materials like uranium, thorium and potassium also added heat

Carleton(arl)S. Fiorina是惠普公司 的主席,总截和首席执行宫。两次被福布 斯》杂志评为美国经济界的最有权力的女性 也被看作是美国成功女性的代表人物

Factors facilitating head s attack transparent performance and fashion cycles The same factors make defense harder

The Uses of History in Law and economics Ron harris During the last quarter of the twentieth century, the humanities and social sciences have turned toward history something that culminated in the 1990s, and this phenomenon was evident in law as well. However until recently law and economics, the most infuential post-World War

KEEPING LEGAL HISTORY MEANINGFUL Richard H. pildes For nearly a generation after the end of reconstruction, conventionally identified as the 1876 disputed Presidential election and subsequent withdrawal of federal troops from the South black Americans' political participation remained surprisingly robust. Even in the 1890s, half of black men continued to vote in key gubernatorial races in Southern states

Detailed study of the text 1. The idea of helping people comes naturally to most of As might be expected, most of us are willing to help others. Most of us will naturally think of helping others Come to sb. :(an idea) to enter someone's mind