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排序方式: 共有82条查询结果,搜索用时 31 毫秒
1.
grp75对细胞缺糖损伤的保护作用   总被引:8,自引:0,他引:8  
为研究grp75的功能,对过表达grp75的CHL细胞进行了无糖培养以施加能量代谢应激,运用台盼蓝染色计数、LDH释放测定和流式细胞术等方法评估其损伤程序。结果显示,无糖培养5h,过表达grp75细胞和对照组细胞比较,细胞活率、亚二倍体细胞率均无明显差别;无糖培养10h,过表达grp75细胞的活率高于对照组(P〈0.01),亚二倍体细胞率低于对照组(P〈0.05);无糖培养至20h,两组细胞活率和  相似文献
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Mad protein has been shown as an antagonist of cMyc protein in some cell lines.The effect of Mad protein to the malignant phenotype of human hepatoma BEL-7404 cell line was investigated experimentally.An eukarryotic vector pCDNA Ⅲ containing full ORF fragment of mad cDNA was transfected into targeted cells.Under G418 selection,stable Mad-overexpressed cells were cloned.Studies on the effect of Mad over-expression in cell proliferation and cell cycle revealed that cell morphology of the Mad-overexpressed BEL-7404-M1 cells was significantly different from the parent and control vector transfected cells.DNA synthesis,cell proliferation and anchorage-independent growth in soft-agar of the madtransfected cells were partially inhibited in comparison to control cells.Flos cytometry analysis indicated that mad over-expression might block more transfectant cells at G0/G1 phase,resulting in the retardation of cell proliferation.RT-PCR detected a marked inhibition of the expression of cdc25A,an important regulator gene of G0/G1 to S phase in cell cycle.It was also found that Mad protein overexpression could greatly suppress p53-mediated apoptosis in BEL-74040M1 cells in the absence of serume.Thus,Mad proteins may function as a negative regulator antagonizing c-Myc activity in the control of cell growth and apoptosis in human hepatocellular carcinoma BEL-7404 cells.  相似文献
4.
CYP6F1 (GenBank/EMBL accession No. AY662654), a novel gene with a complete encoding sequence in the cytochrome P450 family 6, was cloned and sequenced from deltamethrin-resistant 4th instar larvae of Culex pipiens pallens. The cDNA sequence of CYP6F1 has an open reading frame of 1527 bp, which encodes a putative protein of 508 amino acid residues. The deduced amino acid sequence of CYP6F1 indicated that the encoded P450 has conserved domains of a putative membrane-anchoring signal,putative reductase-binding sites, a typical heme-binding site, an ETLR motif and substrate recognition sites.Semi-quantitative RT-PCR analysis indicated that the CYP6F1 gene was expressed to a greater extent in the deltamethrin-resistant strain than in the susceptible strain of Cx. pipiens pallens. The expression levels of the CYP6F1 gene in the deltamethrin-resistant 1 st, 2nd, 3rd, 4th instar larvae and adult female mosquitoes differed, with highest expression levels in the 4th instar larvae. In addition, the CYP6F1 gene was stably expressed in mosquito C6/36 cells, and the expected 61.2 kDa band was identified by Western blotting. The cells transfected with CYP6F1 had an increased resistance to deltamethrin as compared with control cells.These results indicate that CYP6F1 is expressed at higher levels in the deltamethrin-resistant strain, and may confer some insecticide resistance in Cx. pipiens pallens.  相似文献
5.
Zheng L  Ren JQ  Li H  Kong ZL  Zhu HG 《Cell research》2004,14(6):497-506
Overexpression and activation of HER-2/neu (also known as c-erbB-2), a proto-oncogene, was found in about 30% of human breast cancers, promoting cancer growth and making cancer cells resistant to chemo- and radio-therapy.Wild-type p53 is crucial in regulating cell growth and apoptosis and is found to be mutated or deleted in 60-70% of human cancers. And some cancers with a wild-type p53 do not have normal p53 function, suggesting that it is implicated in a complex process regulated by many factors. In the present study, we showed that the overexpression of HER-2/neu could decrease the amount of wild-type p53 protein via activating PI3K pathway, as well as inducing MDM2 nuclear translocation in MCF7 human breast cancer cells. Blockage of PI3K pathway with its specific inhibitor LY294002 caused G1-S phase arrest, decreased cell growth rate and increased chemo- and radio-therapeutic sensitivity in MCF7 cells expressing wild-type p53. However, it did not increase the sensitivity to adriamycin in MDA-MB-453 breast cancer cells containing mutant p53. Our study indicates that blocking PI3K pathway activation mediated by HER-2/neu overexpression may be useful in the treatment of breast tumors with HER-2/neu overexpression and wild-type p53.  相似文献
6.
HAI-1过表达对SW620细胞体外生长和运动能力的影响   总被引:2,自引:0,他引:2  
肝细胞生长因子激活因子抑制因子1(hepatocyte growth factor activator inhibitor type 1,HAI-1)能有效抑制肝细胞生长因子激活因子(hepatocyte growth factor activator,HGFA)和丝氨酸蛋白酶Matriptase的活性,并可通过对HGFA和Matriptase活性的调控参与HGF/c—Met信号传导途径。为了解HAI-1在肿瘤细胞的生长和运动中的作用,本研究将人HAI-1基因全长cDNA克隆至pcDNA3.1( )表达载体,并转染人肠癌SW620细胞,用Western blot验证了转染细胞中HAI-1的表达情况,并分别利用生长曲线、软琼脂集落形成、穿膜运动和扩散运动测定等方法检测了HAI-1过表达对SW620细胞生长和运动能力的影响。生长曲线和软琼脂集落形成测定都显示出HAI-1转染细胞与对照组相比差异不十分明显。穿膜运动和扩散运动测定则均显示了HAI-1过表达对细胞运动能力有明显的抑制。因此,HAI-1的过表达虽然在体外对肿瘤细胞生长影响较小,但可以抑制肿瘤细胞的运动迁移能力。  相似文献
7.
一氧化氮诱导食管癌细胞线粒体DNA编码基因过表达   总被引:2,自引:0,他引:2       下载免费PDF全文
以人食管癌细胞系EC109作为驱赶方(driver),以被一氧化氮(nitric oxid,NO)诱导的EC109作为实验方(tester),应用抑制消减杂交(suppression subtractive hybridization, SSH)、反向mRNA斑点印迹和RNA印迹等技术手段研究了NO诱导的食管癌细胞中基因的过表达情况.然后对过表达基因的表达序列标签(expressed sequence tag,EST)实施序列测定,并与GenBank进行BLAST同源性比较和序列突变分析.结果先后两次从69个SSH阳性克隆中共鉴定出6个线粒体DNA(mitochondrial DNA, mtDNA)编码的基因,即ND-4L、ND-4、COX-2、Lys-tRNA、ATP-8和ATP-6.表明NO可以诱导食管癌细胞mtDNA编码的基因过表达.另外,在ND-4L/ND-4基因的片段(10 736~11 449)上发现了三处同型单核苷酸置换(10 872 T→C, 11 001 A→G, 11 346 A→G),在COX-2/Lys-tRNA/ATP-8/ATP-6基因片段(8 011~8 589)上发现了一处单核苷酸缺失(8 380 A).氨基酸序列分析表明,在NO诱导的EC109中可能存在着一种结构异常的ATP-8肽链(一条在N端被截短的只有11个氨基酸残基的肽链,而正常的ATP-8肽链为68个氨基酸残基).这些研究结果为深入揭示NO对肿瘤细胞的作用机制提供了新的重要线索.  相似文献
8.
肌肉生长抑制素(MSTN)是抑制肌肉生长和发育的重要生长调控因子.通过cDNA末端快速扩增法(RACE)克隆草鱼MSTN-1型和MSTN-2型全长cDNA.RT-PCR分析结果表明,MSTN-1在草鱼肌肉、脑和眼中的转录量较高,在肝胰脏、脾脏和心的转录量较低,在肠、腮、性腺和肾中无表达;MSTN-2只在脑和肌内中有表达.在草鱼胚胎发育的0-36 hpf期间,MSTN-1的转录量较低;在胚胎发育的36-48 hpf期间,其转录量呈逐渐升高的趋势;MSTN-2各时相均无表达,可能因为该基因在草鱼胚胎发育过程中不起重要作用.通过分别显微注射MSTN-1型和MSTN-2型mRNA至斑马鱼1-2细胞期胚胎.结果显示,注射MSTN-1型mRNA过表达可导致斑马鱼体节发生期胚胎的前-后轴拉长,背-腹轴变短,脊索轻微扭曲,以及体节发育受到强烈抑制而不分化等现象.注射MSTN-2型mRNA胚胎早期发育有所延迟并未发生明显变化,但发育至60h之后尾部明显发生严重弯曲.  相似文献
9.
Ma YH  Hu JH  Zhou XG  Zeng RW  Mei ZT  Fei J  Guo LH 《Cell research》2000,10(4):303-310
Transgenic mice ubiquitously overexpressing murine γ-aminobutyric acid transporter subtype I were created.Unexpectedly,these mice markedly exhibited heritable obesity,which features significantly increased body weight and fat deposition.Behavioral examination revealed that transgenic mice have slightly reduced spontaneous locomotive capacity and altered feeding pattern.This preliminary finding indicates that the inappropriate level of γ-aminobutyric acid transporters may be directly or indirectly involved in the pathogenic mechanism underlying certain types of obesity.  相似文献
10.
Ma YH  Hu JH  Zhou XG  Mei ZT  Fei J  Guo LH 《Cell research》2000,10(1):59-69
γ-Aminobutyric acid and GABAergic receptors were previously reported to be distributed in reproductive systems besides CNS and predicted to participate in the modulation of testicular function.γ-Aminobutyric acid transporter was implicated to be involved in this process.However,the potential role of γ-aminobutyric transporter in testis has not been explored.In this study,we investigated the existence of mouse γ-aminobutyric acid transporter subtype I (mGAT1) in testis.Wild-type and transgenic mice,which overexpressing mGAT1 in a variety of tissues,especially in testis,were primarily studied to approach the profile of mGAT1 in testis.Mice with overexpressed mGAT1 develop normally but with reduced mass and size of testis as compared with wild-type.Testicular morphology of transgenic mice exhibited overt abnormalities including focal damage of the spermatogenic epithelium accompanied by capillaries proliferation and increased diameter of seminiferous tubules lumen.Reduced number of spermatids was also found in some seminiferous tubules.Our results clearly demonstrate the presence of GAT1 in mouse testis and imply that GAT1 is possibly involved in testicular function.  相似文献
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