全文获取类型
收费全文 | 169篇 |
免费 | 22篇 |
出版年
2021年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 1篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1965年 | 2篇 |
排序方式: 共有191条查询结果,搜索用时 31 毫秒
61.
Timothy John Tranbarger Wanwisa Kluabmongkol Duangjai Sangsrakru Fabienne Morcillo James W Tregear Somvong Tragoonrung Norbert Billotte 《BMC plant biology》2012,12(1):1
Background
The oil palm (Elaeis guineensis Jacq.) is a perennial monocotyledonous tropical crop species that is now the world's number one source of edible vegetable oil, and the richest dietary source of provitamin A. While new elite genotypes from traditional breeding programs provide steady yield increases, the long selection cycle (10-12 years) and the large areas required to cultivate oil palm make genetic improvement slow and labor intensive. Molecular breeding programs have the potential to make significant impacts on the rate of genetic improvement but the limited molecular resources, in particular the lack of molecular markers for agronomic traits of interest, restrict the application of molecular breeding schemes for oil palm. 相似文献62.
The relaxin receptor, RXFP1, is a member of the leucine-rich repeat-containing G-protein-coupled receptor (LGR) family. These receptors are characterized by a large extracellular ectodomain containing leucine-rich repeats which contain the primary ligand binding site. RXFP1 contains six putative Asn-linked glycosylation sites in the ectodomain at positions Asn-14, Asn-105, Asn-242, Asn-250, Asn-303, and Asn-346, which are highly conserved across species. N-Linked glycosylation is the most common post-translational modification of G-protein-coupled receptors, although its role in modulating receptor function differs. We herein investigate the actual N-linked glycosylation status of RXFP1 and the functional ramifications of these post-translational modifications. Site-directed mutagenesis was utilized to generate single- or multiple-glycosylation site mutants of FLAG-tagged human RXFP1 which were then transiently expressed in HEK-293T cells. Glycosylation status was analyzed by immunoprecipitation and Western blot and receptor function analyzed with an anti-FLAG ELISA, (33)P-H2 relaxin competition binding, and cAMP activity measurement. All of the potential N-glycosylation sites of RXFP1 were utilized in HEK-293T cells, and importantly, disruption of glycosylation at individual or combinations of double and triple sites had little effect on relaxin binding. However, combinations of glycosylation sites were required for cell surface expression and cAMP signaling. In particular, N-glycosylation at Asn-303 of RXFP1 was required for optimal intracellular cAMP signaling. Hence, as is the case for other LGR family members, N-glycosylation is essential for the transport of the receptor to the cell surface. Additionally, it is likely that glycosylation is also essential for the conformational changes required for G-protein coupling and subsequent cAMP signaling. 相似文献
63.
64.
65.
Ping Fu Ross A. D. Bathgate Geoffrey W. Tregear John D. Wade 《International journal of peptide research and therapeutics》2003,10(5-6):387-391
Summary Insulin-like peptide 3 (INSL3) is one of ten members of the human insulin superfamily and consists of two peptide chains that
contain the characteristic insulin fold and disulfide bond pairings. It is primarily produced in the Leydig cells of the testes,
and gene knockout experiments have identified a key biological role as initiating testes descent during foetal development.
Its receptor has recently been shown to be a member of the leucine-rich repeat-containing G-protein-coupled receptor family
(LGR) and is known as LGR8. Considerable work has recently been undertaken with the aim of studying the mechanism of INSL3
downstream action on responsive cells and, towards this goal, the use of synthetic peptides has proved particularly beneficial.
This mini-review outlines how these together with basic structure-function studies are beginning to reveal not only its molecular
actions but also its potential new biological actions. 相似文献
66.
Daniel J. Scott Tracey Wilkinson Geoffrey W. Tregear Ross A. D. Bathgate 《International journal of peptide research and therapeutics》2003,10(5-6):393-400
Relaxin-1 is a heterodimeric peptide hormone primarily produced by the pregnant corpus luteum and/or placenta and is involved
in many essential physiological processes centered on its action as a potent extracellular matrix (ECM) remodeling agent.
Insulin-like peptide 3 (INSL3), also known as relaxin-like factor, is predominantly expressed in the Leydig cells of the testes
and is an important mediator of testicular descent. The relaxin-1 equivalent peptide in humans is actually the product of
the human RLN2 gene, human 2 (H2) relaxin. Recently identified and thought to be the ancestral relaxin, relaxin-3 is specifically expressed
in the nucleus incertus of the mouse and rat brain and is most likely an important neuropeptide. Each of the hormones above
act on cell membrane G-protein coupled receptors (GPCRs). The relaxin-1 receptor is leucine-rich repeat-containing GPCR 7
(LGR7) whereas INSL3 acts on the closely related LGR8. These receptors have large extra-cellular domains containing multiple
leucine-rich repeats (LRRs) and a unique LDL receptor-like cysteine-rich motif (LDLR-domain). Relaxin-3 will bind and activate
LGR7 with 50-fold lower activity than H2 relaxin. Two relaxin-3 selective GPCRs; somatostatin and angiotensin like peptide
receptor (SALPR) and GPCR 142 were recently identified, these type I GPCRs are unrelated to LGR7 and LGR8. The discovery and
characterisation of these receptors is greatly aiding the quest to unravel the mechanics of these important hormones, however
with three other family members, insulin-like peptides 4–6 (INSL4, INSL5 and INSL6) with unknown functions and unidentified
receptors, there is still much to be learnt about this hormone family. 相似文献
67.
68.
Positions of multiple insertions in SSU rDNA of lichen-forming fungi 总被引:11,自引:3,他引:8
Lichen-forming fungi, in symbiotic associations with algae, frequently have
nuclear small subunit ribosomal DNA (SSU rDNA) longer than the 1,800
nucleotides typical for eukaryotes. The lichen-forming ascomycetous fungus
Lecanora dispersa contains insertions at eight distinct positions of its
SSU rDNA; the lichen-forming fungi Calicium tricolor and Porpidia
crustulata each contain one insertion. Insertions are not limited to fungi
that form lichens; the lichen ally Mycocalicium albonigrum also contains
two insertions. Of the 11 insertion positions now reported for
lichen-forming fungi and this ally, 6 positions are known only from
lichen-forming fungi. Including the 4 newly reported in this study,
insertions are now known from at least 17 positions among all reported SSU
rDNA sequences. Insertions, most of which are Group I introns, are reported
in fungal and protistan lineages and occur at corresponding positions in
genomes as phylogenetically distant as the nuclei of fungi, green algae,
and red algae. Many of these positions are exposed in the mature rRNA
tertiary structure and may be subject to independent insertion of introns.
Insertion of introns, accompanied by their sporadic loss, accounts for the
scattered distribution of insertions observed within the SSU rDNA of these
diverse organisms.
相似文献
69.
John D. Wade John W. Perich Michael J. McLeish Laszlo Otvos Jr. Geoffrey W. Tregear 《Letters in Peptide Science》1995,2(2):71-76
Summary The continuous-flow Fmoc solid-phase synthesis methodology was used together with the derivative Fmoc-Tyr(PO3Bzl2)-OH to successfully prepare an O-phosphorylated tyrosine analogue of a heptadecapeptide which was designed to adopt an -helical conformation in solution. Comprehensive chemical characterization, including ion-spray mass spectrometry, confirmed the high purity of the synthetic peptide and the presence of the tyrosine O-phosphate moiety. Circular dichroism spectroscopic analysis showed that, in water and at low concentration, the peptide has a greater degree of helicity or possibly a longer helix chain length than the non-O-phosphorylated form. A similar phenomenon was observed in the membrane-mimicking solvent octyl -glucoside. The increase in the helicity during trifluoroethanol titration and the absence of apparent coiled coil-type aggregation further demonstrated the intrinsic ability of the peptides to form -helices. The data, taken together, indicate that, at least for this peptide, the -helix secondary structural element is more pronounced following tyrosine O-phosphorylation. 相似文献
70.
The extent of polylactosamine glycosylation of MDCK LAMP-2 is determined by its Golgi residence time 总被引:2,自引:1,他引:1
The increased polylactosamine glycosylation of LAMP-2 in MDCK cells
cultured for 1 day relative to cells cultured for 3 days has been
correlated with its slower rate of Golgi transit (Nabi and Rodriguez-
Boulan, 1993, Mol. Biol. Cell., 4, 627-635). To determine if the
differential polylactosamine glycosylation of LAMP-2 is a consequence of
glycosyltransferase expression levels, the activities of beta1- 6GlcNAc-TV,
beta1-3GlcNAc-T(i), beta1-2GlcNAc-TI, beta1, 4Gal-T, alpha2- 6sialyl-T, and
alpha2-3sialyl-T were assayed and no significant differences in the
activities of these enzymes in 1 and 3 day cell extracts were detected.
During MDCK epithelial polarization, the Golgi apparatus undergoes
morphological changes and apiconuclear Golgi networks were more evident in
3 day cells. Treatment with nocodazole disrupted Golgi networks and
generated numerous Golgi clusters in both 1 day and 3 day cells. In the
presence of nocodazole the differential migration of LAMP-2 in 1 and 3 day
MDCK cells was maintained and could be eliminated by treatment with
endo-beta-galactosidase, indicating that gross Golgi morphology did not
influence the extent of LAMP-2 polylactosamine glycosylation. Nocodazole
treatment did, however, result in the faster migration of LAMP-2 which was
not due to modification of core N-glycans as the precursor form of the
glycoprotein migrated with an identical molecular size. Following
incubation at 20 degrees C, which prevents the exit of proteins from the
trans-Golgi network, the molecular size of LAMP-2 increased to a similar
extent in both 1 and 3 day MDCK cells. Extending the time of incubation at
20 degrees C did not influence the size of LAMP-2, demonstrating that its
glycosylation is modified not by its retention within the Golgi but rather
by its equivalent slower Golgi passage at the lower temperature in both 1
and 3 day cells. An identical effect was observed in nocodazole treated
cells, demonstrating that Golgi residence time determines the extent of
LAMP-2 polylactosamine glycosylation, even in isolated Golgi clusters.
相似文献