首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
The role of transferrin in iron metabolism is evaluated, both with regard to iron uptake by transferrin and to iron uptake from transferrin by different cells. The heterogeneity of serum transferrin is described and the implications of the heterogeneity are discussed. The composition of ferritin is given and the value of serum ferritins are discussed.  相似文献   

10.
李小强 《人类学学报》2022,41(6):1097-1108
农业是文明形成和发展的基础。约1万年以前,农业在西亚、中美洲和东亚地区几乎同时独立出现。西亚的两河流域被认为是小麦、大麦、燕麦等作物的起源中心;中美洲则是玉米、马铃薯和花生等农作物的诞生地;中国拥有两套独立的原始农业系统,分别是起源于长江中下游地区的稻作农业和黄河中游地区的粟-黍旱作农业,孕育了中华农耕文明。西亚的小麦农业、东亚的稻作和粟-黍农业逐步传播到世界上大多数地区,促进了早期农业全球化。15世纪末,新航路的开辟和众多贸易路线的出现加快了欧亚大陆和美洲大陆农作物的传播和融合,加速了农业全球化进程。农业的发展改变了人类改造和适应环境的能力;促进了人类定居,导致人群结构的重大变革,出现劳动分工和商品交换等,为人类提供了稳定的食物供应及储存,推动了人口的增长。农业起源和发展极大地增强了人类活动的强度和范围,深刻地影响着全球生态和气候环境。  相似文献   

11.
12.
13.
The rise, decline, and fall of LSD   总被引:1,自引:0,他引:1  
  相似文献   

14.
15.
16.
E. D. Sverdlov 《Genetica》1991,85(1):91-101
The review is devoted to analysis of research carried out in the author's laboratory on structure-function relationships in genes coding for Na, K-ATPases. Also considered are problems related to molecular evolution of ion-transporting ATPases.This brief review is devoted to a fragment of research carried out in my laboratory, the Laboratory of Human Genes Structure and Function at the Shemyakin Institute of Bioorganic Chemistry, USSR Academy of Sciences. The area of the review may be named as structural-evolutionary analysis of functional anatomies of genes. The approach is fairly standard and its essence was formulated long ago: evolution decides to be or not to be based on usefulness or lack of it. The elements of genes that are important for the gene function are retained in the course of evolution, and a comparison of genes having similar functions in different species should, hopefully, reveal different behavior of gene blocks, conservation of functionally significant blocks and variability of less significant or insignificant ones. An approach like this has been widely used in comparing proteins. However, a study of genes gives the investigator yet another tool of structural and evolutionary import: the exon structure may be relevant to the gene's evolutionary history, with exons corresponding to the functional domains arguments for and against this fascinating hypothesis have been reviewed by Blake (Blake, 1985).However, even if the exon-domain correlation does not hold in the general case, a similarity in the exon-intron pattern of genes from different species is indicative of their common evolutionary origin and is enforcing the logic of variability analysis, provided, of course, that the compared genes have a common predecessor.A few years ago we employed this approach to analyze the functional structure of genes coding for subunits of bacterial DNA-dependent RNA polymerases and constructed functional maps of the enzyme. After that, a similar study of Na,K-ATPase genes to be reviewed here was started. The entire project became possible through collaboration with the lab of Dr. N. N. Modyanov, an eminent specialist in protein chemistry who had already accumulated considerable information on Na,K-ATPase from pig kidneys by that time. I would also like to stress that the work has been started on the initiative of the deceased Director of the Institute, Yu. A. Ovchinnikov. Since this is a self-review, I am asking my colleagues whose work will not be cited here to excuse me. More objective information can be found in the reviews published on the subject (Cantley, 1981, Jorgensen et al., 1982; Lingrel et al., 1989; Pedersen & Carafoli, 1987; Rossier et al., 1987; Sweadner, 1989).  相似文献   

17.
18.
19.
The Folk Classification of Ceramics: A Study of Cognitive Prototypes . Willett Kempton . New York: Academic Press, 1981. xvi + 237 pp. $24.50 (cloth).  相似文献   

20.
In 1981 the Herbarium of Wesleyan University, Middletown, Connecticut (WECO) was donated to the New York Botanical Garden (NY). We present here an index to the collectors and a list of the verified types in the WECO Herbarium.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号