异域作用因子

基因表达时基因携带的遗传信息从世代相传的遗传物质DNA上通过转录传递到RNA，然后由RNA指导合成蛋白质，从而表现出基因的生物活性。基因的表达受环境因素的影响，并受生物体的控制。真核生物的基因表达在不同水平上受到调控。在细胞核中有转录时的调控，它决定基因是否能被转     

略谈真菌和植物之间的相互关系

真菌曾被列入植物的范畴，被作为植物学的一个分支学科的研究对象，它们被看作一类不含叶绿体的植物。目前已经了解，在地球上真菌的种类在１００万种以上，而维管植物的种类在３０－３５万种之间。因此，研究和了解地球上这两组庞大的生物群体之间的相互关系是十分有意义的，也是目前非常活跃的科学领域。真菌和植物之间的相互作用，有相互依赖，也即相生的一面。现代化石和分子方面的证据证实，真菌和植物的这种相互作用是从远古开始的，是从这二组生物群体出现在陆地上就开始的。事实上，学者认为，最远古、最原始的植物可能是借助于同真…     

追溯山茱萸科植物的性状进化和生物地理学历史——方法选择的影响?

This study compares results on reconstructing the ancestral state of characters and ancestral areas of distribution in Cornaceae to gain insights into the impact of using different analytical methods. Ancestral character state reconstructions were compared among three methods (parsimony, maximum likelihood, and stochastic character mapping) using MESQUITE and a full Bayesian method in BAYESTRAITS and inferences of ancestral area distribution were compared between the parsimony-based dispersal-vicariance analysis (DIVA) and a newly developed maximum likelihood (ML) method. Results indicated that among the six inflorescence and fruit characters examined, "perfect" binary characters (no homoplasy, no polymorphism within terminals, and no missing data) are little affected by choice of method, while homoplasious characters and missing data are sensitive to methods used. Ancestral areas at deep nodes of the phylogeny are substantially different between DIVA and ML and strikingly different between analyses including and excluding fossils at three deepest nodes. These results, while raising caution in making conclusions on trait evolution and historical biogeography using conventional methods, demonstrate a limitation in our current understanding of character evolution and biogeography. The biogeographic history favored by the ML analyses including fossils suggested the origin and early radiation of Cornus likely occurred in the late Cretaceous and earliest Tertiary in Europe and intercontinental disjunctions in three lineages involved movements across the North Atlantic Land Bridge (BLB) in the early and mid Tertiary. This result is congruent with the role of NALB for post-Eocene migration and in connecting tropical floras in North America and Africa, and in eastern Asia and South America. However, alternative hypotheses with an origin in eastern Asia and early Trans-Beringia migrations of the genus cannot be ruled out.     

神经营养因子基因转移载体研究进展

基因治疗可能是预防神经元变性的最有用的方法。腺病毒载体、腺相关病毒载体及逆转录病毒载体等，作为将神经营养因子基因转移珐以非神经元细胞为靶细胞的主要方法，具有潜在的区域特异性、持续性、而受性的特点，并能稳定表达神经营养因子蛋白，右逆转衰老等多种因素导致的胆碱能神经元变性，引起功能的恢复。     

测定二氧化碳浓度的注射法

红外线二氧化碳分析仪是测定植物光合作用和呼吸作用或其所处环境中二氧化碳浓度的常用仪器。测定过程中的气流通过分析仪时，需要一定的平衡时间才能得到一个稳定的读数，要想测出只有几十毫升的气体中的二氧化碳浓度变化非常困难。为此，我们参照Qop等人［‘］的方法，对测定     

封面植物简介——丽江杓兰(英文)

Cypripediumlichiangense S.C.Chen & P.J.Cribb (Orchidaceae),endemic to China,is an endangered species according to I UCN Red List criteria (IUCN,2001:I UCN Red List Categories and Criteria,Version