首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   23篇
  免费   1篇
  2021年   1篇
  2018年   1篇
  2013年   3篇
  2011年   2篇
  2010年   2篇
  2009年   2篇
  2007年   2篇
  2005年   1篇
  2003年   1篇
  1999年   2篇
  1996年   1篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有24条查询结果,搜索用时 15 毫秒
1.
The effect of gibberellin A1 (GA1) on production of ethylene by cowpea (Vigna sinensis cv Blackeye pea no. 5) epicotyl explants and its relationship to epicotyl elongation was investigated. The explants were placed upright in water and incubated in sealed culture tubes or in large jars. GA, and IAA in ethanol solution were injected into the subapical tissues of the decapitated epicotyls. Cowpea epicotyl explants elongated after GA but not after IAA treatment, and they were very sensitive to exogenous ethylene. As little as 0.14 1/1 ethylene reduced significantly GA1-induced epicotyl elongation.Treatment with GA1 induced the production of ethylene which began 10 h after GA application, showed a peak at about 22 h and then declined. The yield of ethylene was proportional to the amount of GA, injected. The inhibition of epicotyl elongation in closed tubes was avoided by absorbing ethylene released with Hg(Cl04)2 , or by adding AVG to the incubation solution to inhibit ethylene production. Treatment with IAA elicited a rapid production of ethylene which ceased about 10 h after application. The effects of IAA and GA1 on ethylene production were additive.Abbreviations AVG aminoethoxyvinylglycine 2-amino-4-(2-aminoethoxy)-trans-3butenoic acid - ACC 1-aminocyclopropane-1-carboxylic acid - GA gibberellin - IAA indole-3-acetic acid  相似文献   
2.
Catechol oxidase was extracted from an acetone powder prepared from green olive. The enzyme was purified 240-fold by ammonium sulphate fractionation followed by ion exchange chromatography and gel filtration. The enzyme was characterized by substrate specificity and response to inhibitors. Between 7 and 9 bands having catechol oxidase activity could be detected by gel electrophoresis and electrofocusing. The purified enzyme had an estimated MW of 42 000. The enzyme was strongly inhibited by diethyldithiocarbamate. Inhibition by chloride was strongly dependent on pH. The enzyme did not oxidise monophenols.  相似文献   
3.
Replacement of the highly basic benzamidine moiety of NAPAP by the moderately basic 1-aminoisoquinoline moiety resulted in thrombin inhibitors with improved selectivity towards trypsin and enhanced Caco-2 cell permeability.  相似文献   
4.
5.
6.
Deficiency of mitochondrial thymidine kinase (TK2) is associated with mitochondrial DNA (mtDNA) depletion and manifests by severe skeletal myopathy in infancy. In order to elucidate the pathophysiology of this condition, mitochondrial deoxyribonucleoside triphosphate (dNTP) pools were determined in patients' fibroblasts. Despite normal mtDNA content and cytochrome c oxidase (COX) activity, mitochondrial dNTP pools were imbalanced. Specifically, deoxythymidine triphosphate (dTTP) content was markedly decreased, resulting in reduced dTTP:deoxycytidine triphosphate ratio. These findings underline the importance of balanced mitochondrial dNTP pools for mtDNA synthesis and may serve as the basis for future therapeutic interventions.  相似文献   
7.
Replacement of the highly basic benzamidine moiety with moderate basic amino-bicycloaryl moieties in a series of thrombin inhibitors related to NAPAMP provided potent enzyme inhibition and significant improvements in membrane transport and oral bioavailability.  相似文献   
8.
Isofemale lines of two populations of Drosophila melanogaster, originating from France and Tanzania, were examined over a range of temperatures. Morphological traits showed distinct patterns in phenotypic plasticity; flies of the two populations differed in shape. Genotype-by-Environment (G*E) interactions were frequently found in the Tanzania population, but were hardly present in the France population. If G*E interaction was present over temperature, estimates of additive genetic variance and additive genetic covariance were made to compare theoretical models with our data. The conclusion is that in France Drosophila melanogaster has been selected over a wider range of temperatures, resulting in parallel reaction norms of more optimal slope. In contrast, selection must have taken place over a narrower temperature range in Tanzanian flies, and will have exerted no direct influence on the slope of the reaction norm.  相似文献   
9.
10.
The effects of several photosynthetic inhibitors and uncouplers of oxidative phosphorylation on NO3 and NO2 assimilation were studied using detached barley (Hordeum vulgare L. cv Numar) leaves in which only endogenous NO3 or NO2 were available for reduction. Uncouplers of oxidative phosphorylation greatly increased NO3 reduction in both light and darkness, while photosynthetic inhibitors did not.

The NO2 concentration in the control leaves was very low in both light and darkness; 98% or more of the NO2 formed from NO3 was further assimilated in control leaves. More NO2 accumulated in the leaves in light and darkness in the presence of photosynthetic inhibitors. Of this NO2, 94% or more was further assimilated. It appears that metabolites, either external or internal to the chloroplast, capable of reducing NADP (which, in turn, could reduce ferredoxin via NADP reductase) might support NO2 reduction in darkness and light when photosynthetic electron flow is inhibited by photosynthetic inhibitors.

Nitrite assimilation was much more sensitive to uncouplers in darkness than in light: in darkness, 74% or more of NO2 formed from NO3 was further assimilated, whereas in light, 95% or more of the NO2 was further assimilated.

  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