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排序方式: 共有75条查询结果,搜索用时 15 毫秒
41.
Anis Limami Belinda Phillipson Rafiqa Ameziane Nicolas Pernollet Qunji Jiang Roselyne Roy Eliane Deleens Muriel Chaumont-Bonnet Peter M. Gresshoff Bertrand Hirel 《Planta》1999,209(4):495-502
To investigate the contribution of root cytosolic glutamine synthetase (GS) activity in plant biomass production, two different
approaches were conducted using the model legume Lotus japonicus. In the first series of experiments, it was found that overexpressing GS activity in roots of transgenic plants leads to
a decrease in plant biomass production. Using 15N labelling it was shown that this decrease is likely to be due to a lower nitrate uptake accompanied by a redistribution
to the shoots of the newly absorbed nitrogen which cannot be reduced due to the lack of nitrate reductase activity in this
organ. In the second series of experiments, the relationship between plant growth and root GS activity was analysed using
a series of recombinant inbred lines issued from the crossing of two different Lotus ecotypes, Gifu and Funakura. It was confirmed that a negative relationship exists between root GS expression and plant biomass
production in both the two parental lines and their progeny. Statistical analysis allowed it to be estimated that at least
13% of plant growth variation can be accounted for by variation in GS activity.
Received: 24 September 1998 / Accepted: 14 April 1999 相似文献
42.
Dianne Sako Asya V. Grinberg June Liu Monique V. Davies Roselyne Castonguay Silas Maniatis Amy J. Andreucci Eileen G. Pobre Kathleen N. Tomkinson Travis E. Monnell Jeffrey A. Ucran Erik Martinez-Hackert R. Scott Pearsall Kathryn W. Underwood Jasbir Seehra Ravindra Kumar 《The Journal of biological chemistry》2010,285(27):21037-21048
The single transmembrane domain serine/threonine kinase activin receptor type IIB (ActRIIB) has been proposed to bind key regulators of skeletal muscle mass development, including the ligands GDF-8 (myostatin) and GDF-11 (BMP-11). Here we provide a detailed kinetic characterization of ActRIIB binding to several low and high affinity ligands using a soluble activin receptor type IIB-Fc chimera (ActRIIB.Fc). We show that both GDF-8 and GDF-11 bind the extracellular domain of ActRIIB with affinities comparable with those of activin A, a known high affinity ActRIIB ligand, whereas BMP-2 and BMP-7 affinities for ActRIIB are at least 100-fold lower. Using site-directed mutagenesis, we demonstrate that ActRIIB binds GDF-11 and activin A in different ways such as, for example, substitutions in ActRIIB Leu79 effectively abolish ActRIIB binding to activin A yet not to GDF-11. Native ActRIIB has four isoforms that differ in the length of the C-terminal portion of their extracellular domains. We demonstrate that the C terminus of the ActRIIB extracellular domain is crucial for maintaining biological activity of the ActRIIB.Fc receptor chimera. In addition, we show that glycosylation of ActRIIB is not required for binding to activin A or GDF-11. Together, our findings reveal binding specificity and activity determinants of the ActRIIB receptor that combine to effect specificity in the activation of distinct signaling pathways. 相似文献
43.
Bruno Delobel Ratib Djlelati Odette Gabriel-Robez Marie-Françoise Croquette Roselyne Rousseaux-Prévost Jean Rousseaux Jean-Marc Rigot Y. Rumpler 《Human genetics》1998,102(1):98-102
An apparently balanced reciprocal translocation 46,X,t(Y;6) (q11.23 ∼ q12;p11.1) was observed in an infertile man with severe
oligozooteratozoospermia. Different mitotic chromosome banding patterns were performed and fluorescence in situ hybridization
indicated a breakpoint in the fluorescent Yq heterochromatin. Molecular genetic deletion experiments for the azoospermia factor
region in distal Yq11 showed the retention of the DAZ gene and meiotic pairing configurations suggested that the man’s infertility
could be due to the pairing behaviour of the Y;6 translocation chromosome with the X chromosome visualised by synaptonemal
complex analysis at the electron microscopy level. The morphological appearance of the normal chromosome 6 and the Y;6 translocated
chromosome included in the compartment of the sex vesicle may allow an explanation of the degeneration of most spermatocytes
after the pachytene stage.
Received: 1 August 1997 / Accepted: 25 September 1997 相似文献
44.
45.
Castonguay R Werner ED Matthews RG Presman E Mulivor AW Solban N Sako D Pearsall RS Underwood KW Seehra J Kumar R Grinberg AV 《The Journal of biological chemistry》2011,286(34):30034-30046
Endoglin (CD105), a transmembrane protein of the transforming growth factor β superfamily, plays a crucial role in angiogenesis. Mutations in endoglin result in the vascular defect known as hereditary hemorrhagic telangiectasia (HHT1). The soluble form of endoglin was suggested to contribute to the pathogenesis of preeclampsia. To obtain further insight into its function, we cloned, expressed, purified, and characterized the extracellular domain (ECD) of mouse and human endoglin fused to an immunoglobulin Fc domain. We found that mouse and human endoglin ECD-Fc bound directly, specifically, and with high affinity to bone morphogenetic proteins 9 and 10 (BMP9 and BMP10) in surface plasmon resonance (Biacore) and cell-based assays. We performed a function mapping analysis of the different domains of endoglin by examining their contributions to the selectivity and biological activity of the protein. The BMP9/BMP10 binding site was localized to the orphan domain of human endoglin composed of the amino acid sequence 26-359. We established that endoglin and type II receptors bind to overlapping sites on BMP9. In the in vivo chick chorioallantoic membrane assay, the mouse and the truncated human endoglin ECD-Fc both significantly reduced VEGF-induced vessel formation. Finally, murine endoglin ECD-Fc acted as an anti-angiogenic factor that decreased blood vessel sprouting in VEGF/FGF-induced angiogenesis in in vivo angioreactors and reduced the tumor burden in the colon-26 mouse tumor model. Together our findings indicate an important role of soluble endoglin ECD in the regulation of angiogenesis and highlight efficacy of endoglin-Fc as a potential anti-angiogenesis therapeutic agent. 相似文献
46.
Marie Tremblay-Franco Nicolas J. Cabaton Cécile Canlet Roselyne Gautier Cheryl M. Schaeberle Fabien Jourdan Carlos Sonnenschein Florence Vinson Ana M. Soto Daniel Zalko 《PloS one》2015,10(10)
Along with the well-established effects on fertility and fecundity, perinatal exposure to endocrine disrupting chemicals, and notably to xeno-estrogens, is strongly suspected of modulating general metabolism. The metabolism of a perinatally exposed individual may be durably altered leading to a higher susceptibility of developing metabolic disorders such as obesity and diabetes; however, experimental designs involving the long term study of these dynamic changes in the metabolome raise novel challenges. 1H-NMR-based metabolomics was applied to study the effects of bisphenol-A (BPA, 0; 0.25; 2.5, 25 and 250 μg/kg BW/day) in rats exposed perinatally. Serum and liver samples of exposed animals were analyzed on days 21, 50, 90, 140 and 200 in order to explore whether maternal exposure to BPA alters metabolism. Partial Least Squares-Discriminant Analysis (PLS-DA) was independently applied to each time point, demonstrating a significant pair-wise discrimination for liver as well as serum samples at all time-points, and highlighting unequivocal metabolic shifts in rats perinatally exposed to BPA, including those exposed to lower doses. In BPA exposed animals, metabolism of glucose, lactate and fatty acids was modified over time. To further explore dynamic variation, ANOVA-Simultaneous Component Analysis (A-SCA) was used to separate data into blocks corresponding to the different sources of variation (Time, Dose and Time*Dose interaction). A-SCA enabled the demonstration of a dynamic, time/age dependent shift of serum metabolome throughout the rats’ lifetimes. Variables responsible for the discrimination between groups clearly indicate that BPA modulates energy metabolism, and suggest alterations of neurotransmitter signaling, the latter finding being compatible with the neurodevelopmental effect of this xenoestrogen. In conclusion, long lasting metabolic effects of BPA could be characterized over 200 days, despite physiological (and thus metabolic) changes connected with sexual maturation and aging. 相似文献
47.
Ifat Bar-joseph Elon Pras Haike Reznik-Wolf Dina Marek-Yagel Almogit Abu-Horvitz Maya Dushnitzky Nurit Goldstein Shlomit Rienstein Michal Dekel Ben Pode-Shakked Joseph Zlotnik Anelia Benarrosh Philippe Gillery Niklaus Hofliger Christiane Auray-Blais Roselyne Garnotel Yair Anikster 《Human genetics》2012,131(11):1805-1810
Sarcosinemia is an autosomal recessive metabolic trait manifested by relatively high concentrations of sarcosine in blood and urine. Sarcosine is a key intermediate in 1-carbon metabolism and under normal circumstances is converted to glycine by the enzyme sarcosine dehydrogenase. We encountered six families from two different descents (French and Arab), each with at least one individual with elevated levels of sarcosine in blood and urine. Using the “candidate gene approach” we sequenced the gene encoding sarcosine dehydrogenase (SARDH), which plays an important role in the conversion of sarcosine to glycine, and found four different mutations (P287L, V71F, R723X, R514X) in three patients. In an additional patient, we found a uniparental disomy in the region of SARDH gene. In two other patients, we did not find any mutations in this gene. We have shown for the first time that mutations in the SARDH gene are associated with sarcosinemia. In addition, our results indicate that other genes are most probably involved in the pathogenesis of this condition. 相似文献
48.
A short synthetic peptide inhibits signal transduction, migration and angiogenesis mediated by Tie2 receptor 下载免费PDF全文
Tie2, an endothelial cell-specific receptor kinase, has an important role in tumour angiogenesis. In an attempt to identify peptides that specifically interact with and block the Tie2 pathway, a phage-displayed peptide library was screened on a recombinant Tie2 receptor. One peptide, NLLMAAS, completely abolished the binding to Tie2 of both angiopoietin 2 and angiopoietin 1 (Ang1). We further show that NLLMAAS specifically suppresses both Ang1-induced ERK activity and migration in human umbilical endothelial cells. Moreover, in vivo, this peptide inhibits angiogenesis in the chick chorioallantoic membrane assay. NLLMAAS is the first peptide described to interact with Tie2. Our results demonstrate that it is an efficient and specific antagonist of the binding of Tie2 ligands, and suggest that this peptide or its derivates may have potential applications in the treatment of angiogenesis diseases. It also represents a potent tool to dissect the molecular mechanisms involved in the Tie2 pathway. 相似文献
49.
The enzyme gamma-glutamyl transpeptidase (GGT), implicated in many physiological processes, catalyses the transfer of a gamma-glutamyl from a donor substrate to an acyl acceptor substrate, usually an amino acid or a peptide. In order to investigate which moieties of the donor substrate are necessary for recognition by GGT, the structure of the well-recognized substrate L-gamma-glutamyl-p-nitroanilide was modified. Several activated esters and their amide derivatives were synthesized and used as substrates. Kinetic (K(m) and V(max)) and inhibition constants (K(i)) were measured and reveal that almost the entire gamma-glutamyl moiety is necessary for recognition in the binding site of the donor substrate. The implied presence of certain complementary amino acids in this substrate binding site will allow the more rational design of various substrate analogues and inhibitors. 相似文献
50.
Analysis of sediments in and around the large and deep burrows made by the callianassid shrimp Callichirus laurae, Jordan Gulf of Aqaba (Red Sea), showed that organic carbon (OC), humic matter (HM), humic (HA) and fulvic acids (FA) are redistributed both quantitatively and qualitatively by sediment reworking activities:
相似文献
1. | OC and humic matter (HM) concentrations are ca. 30 times higher in the stomach content than in surface sand, proving a selective food uptake. |
2. | a 11 to 17 times increase in OC and HM is observed in the mucus-rich burrow wall when compared to ambient sediment. |