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   16篇
  免费   0篇
  2016年   1篇
  2013年   2篇
  2012年   1篇
  2010年   1篇
  2007年   1篇
  2006年   1篇
  2003年   1篇
  2002年   2篇
  1991年   1篇
  1990年   1篇
  1980年   1篇
  1971年   1篇
  1969年   1篇
  1965年   1篇
排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
2.
Root, callus, and cell suspension cultures have been establishedfrom seedlings of Atropa belladonna, L. and Atropa belladonna,cultivar lutea Döll. The growth of these cultures is described.Callus cultures transferred to auxin (-naphthaleneacetic acid)-freemedium initiated roots and shoots. Excised root cultures havebeen established from such roots and plants from such shoots.Extracts of the cultures have been submitted to the Vitali—Morinreaction and following chromatography, to the Dragendorff reaction.Cultured excised roots and plants raised from shoots initiatedon cultured callus were shown to contain atropine (hyoscyamine)and reactive substances corresponding in Rf to hyoscine andcuscohygrine. These alkaloids were absent from cultured callusand cultured cell suspensions and from leaves when initiatedwithout roots on callus. The cultured calluses and cell suspensionscontained choline (0.022–0.027 g per 100 g dry weightof root callus). The growth of cell suspension cultures wasnot inhibited by incorporating atropine sulphate, L-hyoscyamine,L-hyoscine hydrobromide, or DL-scopoline nitrate in the culturemedium at 250 mg/I. These alkaloids were absorbed by the cells,a high proportion of the added alkaloid could be recovered fromthe cultures even after 4 weeks' growth and no evidence wasobtained of the presence of degradation products of the alkaloids.The suppression of alkaloid formation in actively growing callusand cell suspension cultures is discussed.  相似文献   
3.
4.
5.
SYNOPSIS. Under aerobic conditions, we have determined glycerol uptake in the long slender (LS) bloodstream form of Trypanosoma (Trypanozoon) brucei brucei by studying glycerophosphate accumulation in the parasites. The coupled enzyme theory applies to the permeation-phosphorylation sequence. Glycerol passage through the plasma membrane is asymmetric, the efflux process being favored over the influx process. No free diffusion of glycerol can be detected even under conditions under which free glycerol accumulates within the cells; most probably, glycerol permeation is mediated by a specific transport system. In the absence of respiratory activities, glycerol is known to be an end-product of T. brucei glycolysis; its production from glycerophosphate should allow ATP synthesis. The observed efflux of free glycerol following intracellular accumulation of glycerophosphate confirms the hypothesis that glycerol production occurs through reversal of glycerol kinase activity. We conclude that in vivo the role of the carrier-mediated asymmetric permeation process is to prevent inhibition of the reversal of the glycerol kinase-mediated reaction by removing free glycerol.  相似文献   
6.
The present study was undertaken to investigate the pattern of optimal codon usage in Archaea. Comparative analysis was executed to understand the pattern of codon usage bias between the high expression genes (HEG) and the whole genomes in two Archaeal phyla, Crenarchaea and Euryarchaea. The G + C% of the HEG was found to be less in comparison to the genome G + C% in Crenarchaea, whereas reverse was the case in Euryarchaea. The preponderance of U/A ending codons that code for HEG in Crenarchaea was in sharp contrast to the C/G ended ones in Euryarchaea. The analysis revealed prevalence of U-ending codons even within the WWY (nucleotide ambiguity code) families in Crenarchaea vis-à-vis Euryarchaea, bacteria and Eukarya. No plausible interpretation of the observed disparity could be made either in the context of tRNA gene composition or genome G + C%. The results in this study attested that the preferential biasness for codons in HEG of Crenarchaea might be different from Euryarchaea. The main highlights are (i) varied CUB in the HEG and in the whole genomes in Euryarchaea and Crenarchaea. (ii) Crenarchaea was found to have some unusual optimal codons (OCs) compared to other organisms. (iii) G + C% (and GC3) of the HEG were different from the genome G + C% in the two phyla. (iv) Genome G + C% and tRNA gene number failed to explain CUB in Crenarchaea. (v) Translational selection is possibly responsible for A + T rich OCs in Crenarchaea.  相似文献   
7.
8.
9.
10.
Calcific deposits in soft tissue are rare and may clinically resemble a tumour. It seems feasible, therefore, to investigate them by the non-invasive technique of fine needle aspiration cytology (FNAC). In this study three cases with extensive accumulation of acellular calcific material in the breast are described in which FNAC was indicative of soft tissue calcinosis. In all cases routine mammogram had shown a partially cystic opacity. All other investigations were normal and no significant family or medical history was present. Cytopreparations in all cases showed only abundant acellular calcium. The patients had no further treatment and on follow up were clinically well with no changes. The cases are interesting, since the cytohistological findings in the aspirate sample appeared to be strongly indicative of soft tissue calcinosis.  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