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   72篇
  免费   5篇
  2023年   1篇
  2021年   1篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   3篇
  2014年   1篇
  2013年   3篇
  2012年   3篇
  2011年   6篇
  2010年   3篇
  2009年   4篇
  2008年   6篇
  2007年   1篇
  2006年   2篇
  2005年   6篇
  2004年   2篇
  2003年   6篇
  2002年   2篇
  2001年   4篇
  2000年   3篇
  1999年   1篇
  1997年   2篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1968年   1篇
  1967年   2篇
  1966年   1篇
  1965年   2篇
  1964年   2篇
排序方式: 共有77条查询结果,搜索用时 375 毫秒
1.
The rat ErbB2 (rErbB2) protein is a 185‐kDa glycoprotein belonging to the epidermal growth factor‐related proteins (ErbB) of receptor tyrosine kinases. Overexpression and mutations of ErbB proteins lead to several malignancies including breast, lung, pancreatic, bladder and ovary carcinomas. ErbB2 is immunogenic and is an ideal candidate for cancer immunotherapy. We investigated the possibility of expressing the extracellular (EC) domain of rErbB2 (653 amino acids, aa) in Nicotiana benthamiana plants, testing the influence of the 23 aa transmembrane (TM) sequence on protein accumulation. Synthetic variants of the rErbB2 gene portion encoding the EC domain, optimized with a human codon usage and either linked to the full TM domain (rErbB2_TM, 676 aa), to a portion of it (rErbB2‐pTM, 662 aa), or deprived of it (rErbB2_noTM, 653 aa) were cloned in the pEAQ‐HT expression vector as 6X His tag fusions. All rErbB2 variants (72–74.5 kDa) were transiently expressed, but the TM was detrimental for rErbB2 EC accumulation. rERbB2_noTM was the most expressed protein; it was solubilized and purified with Nickel affinity resin. When crude soluble extracts expressing rErbB2_noTM were administered to BALB/c mice, specific rErbB2 immune responses were triggered. A potent antitumour activity was induced when vaccinated mice were challenged with syngeneic transplantable ErbB2+ mammary carcinoma cells. To our knowledge, this is the first report of expression of rErbB2 in plants and of its efficacy in inducing a protective antitumour immune response, opening interesting perspectives for further immunological testing.  相似文献   
2.
Leukemia inhibitory factor (LIF) is a multifunctional glycoprotein that displays multiple biological activities in different cell types, but to date there has been no report on its expression in the normal mammary gland. In this study we found that LIF is expressed at low but detectable levels in postpubertal, adult virgin, and pregnant mouse mammary glands. However, LIF expression drops after parturition to become almost undetectable in lactating glands. Interestingly, LIF expression shows a steep increase shortly after weaning that is maintained for the following 3 days. During this period, known as the first stage of mammary gland involution, the lack of suckling induces local factors that cause extensive epithelial cell death. It has been shown that Stat3 is the main factor in signaling the initiation of apoptosis, but the mechanism of its activation remains unclear. Herein, we show that LIF expression in the gland is induced by milk stasis and not by the decrease of circulating lactogenic hormones after weaning. Implantation of LIF containing pellets in lactating glands results in a significant increase in epithelium apoptosis. In addition, this treatment also induces Stat3 phosphorylation. We conclude that LIF regulated expression in the mouse mammary gland may play a relevant role during the first stage of mammary gland involution. Our results also show that LIF-induced mammary epithelium apoptosis could be mediated, at least partially, by Stat3 activation.  相似文献   
3.
Cell death in the rat thymus: a minireview   总被引:6,自引:0,他引:6  
During the last decades, the literature has clearly established the fundamental role of the thymus in the development of an effective immune system. During thymocyte development and maturation, potentially autoreactive thymocytes are eliminated by a process known as apoptosis or programmed cell death responsible for the negative selection occurring within the thymus. This process is in sharp contrast to other types of cell death referred to as necrosis. Actually, three different types of cell death have been recently observed morphologically in the rat thymus, i.e. necrosis, apoptosis and clustered cell death. Moreover, among the numerous factors influencing thymocyte cell death, particular attention has been paid to hormones, chemicals, biological compounds and physical agents that may influence the type and/or the extent of cell death. Finally, a brief overview has been devoted to the contribution of mitochondria, nitric oxide, glutathione and intracellular levels of cations in addition to the activity of genes as cdk2, p53, Fas and members' of the Bcl2 family in modulating rat thymus cell death.  相似文献   
4.
5.
Cultured fibroblasts from the dermis of normal subjects and of Pseudoxanthoma elasticum (PXE) patients were analysed for enzyme activity, protein and mRNA expression of metalloproteases (MMP-2, MMP-3, MMP-9, MT1-MMP) and of their specific inhibitors (TIMP-1, TIMP-2 and TIMP-3). MMP-3, MMP-9 and TIMP-3 mRNAs and proteins failed to be detected in both the medium and the cell layer of both controls and PXE patients. MMP-2 mRNA was significantly more expressed in PXE than in control cell lines, whereas MT1-MMP, TIMP-1 and TIMP-2 mRNAs appeared unchanged. MMP-2 was significantly higher in the cell extracts from PXE fibroblasts than in control cells, whereas differences were negligible in the cell medium. Data suggest that PXE fibroblasts have an increased proteolytic potential, and that MMP-2 may actively contribute to connective tissue alterations in this genetic disorder.  相似文献   
6.
Flavescence dorée (FD) is a grapevine disease that afflicts several wine production areas in Europe, from Portugal to Serbia. FD is caused by a bacterium, "Candidatus Phytoplasma vitis," which is spread throughout the vineyards by a leafhopper, Scaphoideus titanus (Cicadellidae). After collection of S. titanus specimens from FD-contaminated vineyards in three different areas in the Piedmont region of Italy, we performed a survey to characterize the bacterial microflora associated with this insect. Using length heterogeneity PCR with universal primers for bacteria we identified a major peak associated with almost all of the individuals examined (both males and females). Characterization by denaturing gradient gel electrophoresis confirmed the presence of a major band that, after sequencing, showed a 97 to 99% identity with Bacteroidetes symbionts of the "Candidatus Cardinium hertigii" group. In addition, electron microscopy of tissues of S. titanus fed for 3 months on phytoplasma-infected grapevine plants showed bacterial cells with the typical morphology of "Ca. Cardinium hertigii." This endosymbiont, tentatively designated ST1-C, was found in the cytoplasm of previtellogenic and vitellogenic ovarian cells, in the follicle cells, and in the fat body and salivary glands. In addition, cell morphologies resembling those of "Ca. Phytoplasma vitis" were detected in the midgut, and specific PCR assays indicated the presence of the phytoplasma in the gut, fat body and salivary glands. These results indicate that ST1-C and "Ca. Phytoplasma vitis" have a complex life cycle in the body of S. titanus and are colocalized in different organs and tissues.  相似文献   
7.
Candidatus Phytoplasma mali’, the causal agent of apple proliferation (AP) disease, is a quarantine pathogen controlled by chemical treatments against insect vectors and eradication of diseased plants. In accordance with the European Community guidelines, novel strategies should be developed for sustainable management of plant diseases by using resistance inducers (e.g. endophytes). A basic point for the success of this approach is the study of endophytic bacteria associated with plants. In the present work, endophytic bacteria living in healthy and ‘Ca. Phytoplasma mali’-infected apple trees were described by cultivation-dependent and independent methods. 16S rDNA sequence analysis showed the presence of the groups Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chlamydiae, and Firmicutes. In detail, library analyses underscored 24 and 17 operational taxonomic units (OTUs) in healthy and infected roots, respectively, with a dominance of Betaproteobacteria. Moreover, differences in OTUs number and in CFU/g suggested that phytoplasmas could modify the composition of endophytic bacterial communities associated with infected plants. Intriguingly, the combination of culturing methods and cloning analysis allowed the identification of endophytic bacteria (e.g. Bacillus, Pseudomonas, and Burkholderia) that have been reported as biocontrol agents. Future research will investigate the capability of these bacteria to control ‘Ca. Phytoplasma mali’ in order to develop sustainable approaches for managing AP.  相似文献   
8.
9.
10.
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