Dual role of cAMP duringDictyostelium development

cAMP plays an essential role duringDictyostelium development both outside and inside the cell. Membrane-bound receptors and adenylyl cyclase are responsible for sensing and producing extracellular cAMP, whereas a phosphodiesterase is responsible for maintaining a low basal level. The molecular events underlying this type of hormone like signalling, which are now beginning to be deciphered, will be presented, in the light of cAMP analogue studies. The importance of intracellular cAMP for cell differentiation has been demonstrated by the central role of the cAMP dependent protein kinase. Mutants as well as strains obtained by reverse genetics will be reviewed which lead to our current understanding of the role of intracellular cAMP in the differentiation of both stalk and spore cells.     

AIDS virus-specific cytotoxic T lymphocytes in lung disorders

Human immunodeficiency virus (HIV) is implicated in the development of AIDS (acquired immune deficiency syndrome). HIV infection leads to the generation of HIV-specific thymus-derived (T) lymphocytes in humans and apes. We describe an experimental system permitting the quantitative and systematic analysis of HIV-specific cytotoxic T lymphocytes (CTL). Functional, HIV-specific CTL are obtained by broncho-alveolar lavage (BAL) from the lungs of seropositive patients with lymphocytic alveolitis. These alveolar CTL: (1) recognize and kill HIV-infected alveolar macrophages in vitro under autologous, but not heterologous, conditions; (2) correspond to standard CTL as they express the CD3 and CD8 surface markers, but not the CD4 marker; and (3) are restricted by class I HLA transplantation antigens in their cytotoxic activities. We propose the hypothesis that interactions between HIV-specific CTL and infected macrophages induce major inflammatory reactions in seropositive patients.     

种植红豆草和春小麦对土壤可溶性盐分运移的影响

通过田间试验，测定了种植红豆草（Onobrychis viciaefolia）和春小麦（Triticum aestivum）对土壤可溶性盐分运移的影响．结果表明：不同绿色覆盖方式对0～20cm土层都具有明显的抑盐效应，随着地上生物量的增加，土壤表层的可溶性盐分下降幅度达16．4％～30．5％；在生育期内，红豆草的抑盐效应（0～20cm土层）较小麦强，红豆草使0～80cm土层脱盐率达23．4％，而小麦使0～80cm土层积盐率达14．2％；单作小麦收获后的空闲地．土壤表层盐分上升速度较裸地快．     

稀土光致发光材料的研究现状和应用

本文就稀土光致发光材料进行了分类 ,对其发光特性作了简要介绍 ,综述了其开发与应用的历史与现状 ,并介绍了其目前在各个领域的应用产品 .     

沉淀二氧化硅载银抗菌剂的制备及其抗菌性能

以沉淀二氧化硅为载体，吸附硝酸银后，在500℃下灼烧，制备了具有抗菌功能的线银沉淀二氧化硅抗菌剂，并检验了其抗菌性能；还对抗菌剂的抗菌机理进行了初步探讨。测试结果表明，沉淀二氧化硅的载银量在7％以上时，所制备的抗菌剂对绿脓杆菌、大肠杆菌和枯草杆菌的杀菌率达到100％，具有优异的抗菌性能，可用于抗菌塑料、抗菌食品包装、抗菌卫生纸和抗菌纺织制品等领域。     

代谢工程和作物改良

基因组学和植物生理生化是通过基因工程改良作物的基础 .借助于这些基础研究 ,通过基因工程调控代谢途径 ,提高了油菜籽粒中的油脂含量和拟南芥种子中的维生素 E活性 ,使水稻的胚乳中能合成维生素A原 ,增加了水稻在碱性土壤中吸收铁的能力 ,展示了代谢工程在定向改良作物中的应用前景