全文获取类型
收费全文 | 202篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
203篇 |
出版年
2023年 | 1篇 |
2021年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 3篇 |
2011年 | 20篇 |
2010年 | 28篇 |
2009年 | 36篇 |
2008年 | 26篇 |
2007年 | 14篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1993年 | 2篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有203条查询结果,搜索用时 0 毫秒
1.
Dimitrij Lang H.Thomas Steely Jr. Chia-Yi Kao Nicholas T. Ktistakis 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1987,910(3)
The contour lengths of linear, double-stranded (ds) RNAs from mycovirus PcV and Pseudomonas bacteriophage ø6 have been measured with samples prepared for the electron microscope from 0.05 to 0.5 M NH4Cl solutions. A linear dependence of contour length on the logarithm of ionic strength was found and compared with that of dsDNA (pBR322, linearized and open-circular forms). Conditions for molecular weight determinations of any natural dsRNA by electron microscopy have been established, and the method has been calibrated with ø6 dsRNA of known nucleotide sequence. The results imply that dsRNA in 0.20 M NH4Cl solution has a rise per basepair of 0.271 nm, which is shorter than that in the A-conformation (4%) and in the A′-conformation (10%). The thermal behavior of dsRNA in terms of melting temperature and exhibition of fine structure of melting curves was found to be generally similar to that of dsDNA, as expected from the literature. Folding of dsRNA in ethanolic solution was similar to that of dsDNA. However, in contrast to dsDNA, coiled coils could not be induced by ethanol, which is consistent with dsRNA being stiffer than dsDNA. Concerning dsDNA, the results show that a contraction in rise per basepair by 0.1 nm is coupled with an increase in the winding angle between basepairs by 0.47°, as qualitatively predicted by polyelectrolyte theory. 相似文献
2.
Inactivation of de novo DNA methyltransferase activity by high concentrations of double-stranded DNA
F. Palitti D. Carotti S. Grünwald M. Rispoli E.P. Whitehead C. Salerno R. Strom D. Drahovsky 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1987,910(3)
The activity of eukaryotic DNA methyltransferase diminishes with time when the enzyme is incubated with high concentrations (200–300 μg/ml) of unmethylated double-stranded Micrococcus luteus DNA. Under similar conditions, single-stranded DNA induces only a limited decrease of enzyme activity. The inactivation process is apparently due to a slowly progressive interaction of the enzyme with double-stranded DNA that is independent of the presence of S-adenosyl-l-methionine. The inhibited enzyme cannot be reactivated either by high salt dissociation of the DNA-enzyme complex or by extensive digestion of the DNA. Among synthetic polydeoxyribonucleotides both poly(dG-dC) · poly(dG-dC) and poly(dA-dT) · poly(dA-dT), but not poly(dI-dC) · poly(dI-dC), cause inactivation of DNA methyltransferase. This inactivation process may be of interest in regulating the ‘de novo’ activity of the enzyme. 相似文献
3.
4.
The stability and dynamics of a double-stranded DNA (dsDNA) is affected by the preferential occupancy of small monovalent molecular ions. Small metal and molecular ions such as sodium and alkyl ammonium have crucial biological functions in human body, affect the thermodynamic stability of the duplex DNA and exhibit preferential binding. Here, using atomistic molecular dynamics simulations, we investigate the preferential binding of metal ion such as Na+ and molecular ions such as tetramethyl ammonium (TMA+) and 2-hydroxy-N,N,N-trimethylethanaminium (CHO+) to double-stranded DNA. The thermodynamic driving force for a particular molecular ion-DNA interaction is determined by decomposing the free energy of binding into its entropic and enthalpic contributions. Our simulations show that each of these molecular ions preferentially binds to the minor groove of the DNA and the extent of binding is highest for CHO+. The ion binding processes are found to be entropically favourable. In addition, the contribution of hydrophobic effects towards the entropic stabilisation (in case of TMA+) and the effect of hydrogen bonding contributing to enthalpic stabilisation (in case of CHO+) have also been investigated. 相似文献
5.
自从1962年Hollings在栽培蘑菇(Agaricus bisporus)中发现第一例真菌病毒以来,迄今已在100多种真菌中发现了病毒,多数含双链RNA基因组。1972年Bozarth报道在R.solani中发现病毒,但未报道该病毒的理化性质。1975年Finlker在R.solani的一个强致病力菌株中分离到双链RNA病毒,它含3个组分dsRNA。 相似文献
6.
Evgenia V. Dolgova Yaroslav R. Efremov Konstantin E. Orishchenko Oleg M. Andrushkevich Ekaterina A. Alyamkina Anastasia S. Proskurina Sergey I. Bayborodin Valeriy P. Nikolin Nelly A. Popova Elena R. Chernykh Alexandr A. Ostanin Oleg S. Taranov Vladimir V. Omigov Alexandra M. Minkevich Vladimir A. Rogachev Sergey S. Bogachev Mikhail A. Shurdov 《Gene》2013
We previously reported that fragments of exogenous double-stranded DNA can be internalized by mouse bone marrow cells without any transfection. Our present analysis shows that only 2% of bone marrow cells take up the fragments of extracellular exogenous DNA. Of these, ~ 45% of the cells correspond to CD34 + hematopoietic stem cells. Taking into account that CD34 + stem cells constituted 2.5% of the total cell population in the bone marrow samples analyzed, these data indicate that as much as 40% of CD34 + cells readily internalize fragments of extracellular exogenous DNA. This suggests that internalization of fragmented dsDNA is a general feature of poorly differentiated cells, in particular CD34 + bone marrow cells. 相似文献
7.
8.
《Bioscience, biotechnology, and biochemistry》2013,77(11):2254-2256
Palatine chrome black 6BN (PCB6BN) is virtually non-fluorescent in an aqueous solution or in the presence of single-stranded DNA (ssDNA), whereas the fluorescence intensity of PCB6BN was linearly enhanced up to 300 μM of double-stranded DNA (dsDNA) base pairs. PCB6BN could be a useful fluorescent probe for quantifying dsDNA even when ssDNA is present for both heterogeneous and homogeneous assays. 相似文献
9.
Kyung Suk Lee Amanda B. Marciel Alexander G. Kozlov Charles M. Schroeder Timothy M. Lohman Taekjip Ha 《Journal of molecular biology》2014
Single-stranded DNA binding proteins (SSBs) selectively bind single-stranded DNA (ssDNA) and facilitate recruitment of additional proteins and enzymes to their sites of action on DNA. SSB can also locally diffuse on ssDNA, which allows it to quickly reposition itself while remaining bound to ssDNA. In this work, we used a hybrid instrument that combines single-molecule fluorescence and force spectroscopy to directly visualize the movement of Escherichia coli SSB on long polymeric ssDNA. Long ssDNA was synthesized without secondary structure that can hinder quantitative analysis of SSB movement. The apparent diffusion coefficient of E. coli SSB thus determined ranged from 70,000 to 170,000 nt2/s, which is at least 600 times higher than that determined from SSB diffusion on short ssDNA oligomers, and is within the range of values reported for protein diffusion on double-stranded DNA. Our work suggests that SSB can also migrate via a long-range intersegment transfer on long ssDNA. The force dependence of SSB movement on ssDNA further supports this interpretation. 相似文献
10.
Kwok Ki Ho Heng ZhangBarbara L. Golden Joe Ogas 《Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms》2013,1829(2):199-210
PICKLE plays a critical role in repression of genes that regulate development identity in Arabidopsis thaliana. PICKLE codes for a putative ATP-dependent chromatin remodeler that exhibits sequence similarity to members of subfamily II of animal CHD remodelers, which includes remodelers such as CHD3/Mi-2 that also restrict expression of developmental regulators. Whereas animal CHD3 remodelers are a component of the Mi-2/NuRD complex that promotes histone deacetylation, PICKLE promotes trimethylation of histone H3 lysine 27 suggesting that it acts via a distinct epigenetic pathway. Here, we examine whether PICKLE is also a member of a multisubunit complex and characterize the biochemical properties of recombinant PICKLE protein. Phylogenetic analysis indicates that PICKLE-related proteins in plants share a common ancestor with members of subfamily II of animal CHD remodelers. Biochemical characterization of PICKLE in planta, however, reveals that PICKLE primarily exists as a monomer. Recombinant PICKLE protein is an ATPase that is stimulated by ssDNA and mononucleosomes and binds to both naked DNA and mononucleosomes. Furthermore, recombinant PICKLE exhibits ATP-dependent chromatin remodeling activity. These studies demonstrate that subfamily II CHD proteins in plants, such as PICKLE, retain ATP-dependent chromatin remodeling activity but act through a mechanism that does not involve the ubiquitous Mi-2/NuRD complex. 相似文献