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排序方式: 共有255条查询结果,搜索用时 15 毫秒
91.
黑麦(Secale cereale)染色体除核仁组成区,着丝粒、端粒能被AgNt)3染色体,还可用BrdU和Hoechst 33258诱导出银染区,本文还对染色体差别银染的机制作了探讨。 相似文献
92.
HLA-A2.1-associated peptides, extracted from human melanoma cells, were used to study epitopes for melanoma-specific HLA-A2.1-restricted cytotoxic T lymphocytes (CTLs) by epitope reconstitution, active peptide sequence characterization and synthetic peptide verification. CTL were generated from tumor-involved nodes by in vitro stimulation, initially with autologous melanoma cells and subsequently with allogeneic HLA-A2.1 positive melanoma cells. The CTLs could lyse autologous and aUogeneic HLA-A2. 1 positive melanomas, but not HLA-A2.1 negative melanomas or HLA-A2.1 positive non-melanomas. The lysis of melanomas could be inhibited by anti-CD3, anti-HLA class I and anti-HLA-A2.1 monoclonal antibodies. HLA-A2.1 molecules were purified from detergent-solubilized human melanoma cells by immunoaffinity column chromatography and further fractionated by reversed phase high performance liquid chromatography. The fractions were assessed for their ability to reconstitute melanoma-specific epitopes with HLA-A2.1 positive antigen-processing mutant T2 cells. Three reconstitution peaks were observed in lactate dehydrogenase release assay. Mass spectrometry and ion-exchange high performance liquid chromatography analysis were used to identify peptide epitopes. Peptides with a mass-to-charge ratio of 948 usually consist of nine amino acid residues. The data from reconstitution experiments confirmed that the synthetic peptides contained epitopes and that the peptides associated with HLA-A2.1 and recognized by melanoma-specific CTL were present in these different melanoma cells. These peptides could be potentially exploited in novel peptide-based antitumor vaccines in immunotherapy for CTL. 相似文献
93.
Trichokirin-S1,a small ribosome-inactivating peptide recently purified from the seeds ofTrichosanthes kirilowii,has potential clinical applications because of its small molecular mass.Two stablestrains of hybridomas (1F11 and 2A5) that can secrete highly specific monoclonal antibodies (mAbs) againstTrichokirin-S1 have been developed using the hybridoma technique.The isotypes of these two mAbs,1F11and 2A5,were determined to be IgG_(2a) and IgG_1,respectively.The affinity constants,which were measuredby non-competitive ELISA,were found to be 2.3×10~8 M~(-1) and 2.8×10~8 M~(-1),respectively.An immunoaffinitymethod using 2A5-coupled Sepharose 4B was successfully developed to purify Trichokirin-S1.These twoantibodies have also been used to detect Trichokirin-S1 in Western blot. 相似文献
94.
Identification of peptides inhibiting adhesion of monocytes to the injured vascular endothelial cells through phage-displaying screening 总被引:1,自引:0,他引:1
Guo Y Zhang J Wang JC Yan FX Zhu BY Huang HL Liao DF 《Acta biochimica et biophysica Sinica》2005,37(4):227-233
Using oxidized low-density lipoprotein (LDL)-injured vascular endothelial cells (ECs) as target cells, peptides specifically binding to the injured ECs were screened from a phage-displaying peptide library by using the whole-cell screening technique after three cycles of the ““““““““““““““““““““““““““““““““““““““““““““““““““““““““““““““““adsorption-elution-amplification““““““““““““““““““““““““““““““““““““““““““““““““““““““““““““““““ procedure. Positive phage clones were identified by ELISA, and the inserted amino acid sequences in the displaying peptides were deduced from confirmation with DNA sequencing. The adhesion rate of ECs to monocytes was evaluated by cell counting. The activity of endothelial nitric oxide synthase (eNOS), and the expression levels of caveolin-1 and intercellular adhesion molecule-1 (ICAM-1) were determined by Western blotting. Six positive clones specifically binding to injured ECV304 endothelial cells were selected from fourteen clones. Interestingly, four phages had peptides with tandem leucine, and two of these even shared an identical sequence. Functional analysis demonstrated that the YCPRYVRRKLENELLVL peptide shared by two clones inhibited the expression of ICAM-1, increased nitric oxide concentration in the culture media, and upregulated the expression of caveolin- 1 and eNOS. As a result, the adhesion rate of monocytes to ECV304 cells was significantly reduced by 12.1%. These data suggest that the anti-adhesion effect of these novel peptides is related to the regulation of the caveolin- 1/nitric oxide signal transduction pathway, and could be of use in potential therapeutic agents against certain cardiovascular diseases initiated by vascular endothelial cell damage. 相似文献
95.
Peptide nucleic acid (PNA) binding-mediated gene regulation 总被引:2,自引:0,他引:2
96.
螅状独缩虫(Cachesium polypinum)遗传多样性的RAPD分析 总被引:5,自引:0,他引:5
用随机扩增多态DNA(RAPD)技术对武汉的汉口(CP-1)、汉阳(CP-2)和武昌(CP-3)三个地区缘毛类的螅状独缩虫(Cachesium polypinum)进行了遗传多样性分析。结果表明:这种动物存在广泛的变异,三个地域群体之间的遗传相似度为0.6522-0.7385(平均值为0.6921),各群体之间遗传相似度大小依次为:CP-2-CP-3〉CP-1-CP-2〉CP-1-CP-3。本文对 相似文献
97.
水稻矮缩病毒基因组第六号片段编码区的cDNA克隆及序列分析 总被引:4,自引:0,他引:4
从水稻矮缩病毒中国福建分离物的基因组中分离出第六号片段的双链RNA,根据已发表的日本分离物第六号片段cDNA全序列合成了两个寡聚核苷酸引物,经过逆转录合成cDNA,应用PCR方法扩增了编码区的基因序列,并将扩增产物克隆到pGEM3Zf(-)载体上。对重组子进行限制性酶切分析和DNA序列分析证明,得到的是RDV第六号片段完整的编码序列,进而构建了亚克隆并进行了全序列测定。结果表明,我们所扩增和克隆的 相似文献
98.
目的考察5-氯水杨醛缩2,4-二羟基苯酰肼对金黄色葡萄球菌的抗菌活性及体外抗氧化活性。方法采用试管法和平板法测定其对金黄色葡萄球菌最小抑菌浓度(MIC)、最小杀菌浓度(MBC),绘制杀菌曲线,并通过扫描电镜研究其作用机制,采用DPPH法测定抗氧化活性。结果该化合物对金黄色葡萄球菌的MIC为2.5 mg/m L,MBC为5 mg/m L。杀菌曲线结果表明该化合物对金黄色葡萄球菌的杀菌作用表现出明显的浓度依赖性。扫描电镜结果表明该化合物的作用机制可能与破坏菌体细胞壁、改变其通透性有关。同时该化合物具有较强的清除自由基的能力。结论 5-氯水杨醛缩2,4-二羟基苯酰肼具有显著的抗金黄色葡萄球菌作用,同时具有较好的体外抗氧化活性。 相似文献
99.