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1.
<正>Research concerning senescence has become a hotspot since the conception of‘cellular senescence’was put forward by Drs.Hayflick and Moorhead over five decades ago[1].Recently,a paper published in Science by Kang and colleagues,which this article aims to comment on,provides evidence of a new pathway involved in senescence[2].Senescence is a physiological and pathological process induced by numerous factors,during which cell growth ceases 相似文献
2.
Zhenbo Cao Suraj Subramaniam Neil J. Bulleid 《The Journal of biological chemistry》2014,289(9):5490-5498
Typical 2-Cys peroxiredoxins are required to remove hydrogen peroxide from several different cellular compartments. Their activity can be regulated by hyperoxidation and consequent inactivation of the active-site peroxidatic cysteine. Here we developed a simple assay to quantify the hyperoxidation of peroxiredoxins. Hyperoxidation of peroxiredoxins can only occur efficiently in the presence of a recycling system, usually involving thioredoxin and thioredoxin reductase. We demonstrate that there is a marked difference in the sensitivity of the endoplasmic reticulum-localized peroxiredoxin to hyperoxidation compared with either the cytosolic or mitochondrial enzymes. Each enzyme is equally sensitive to hyperoxidation in the presence of a robust recycling system. Our results demonstrate that peroxiredoxin IV recycling in the endoplasmic reticulum is much less efficient than in the cytosol or mitochondria, leading to the protection of peroxiredoxin IV from hyperoxidation. 相似文献
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We have used diffusion and branching process methods to investigate fixation rates, probabilities of survival per generation, and times to fixation of mutant genes under different selection methods incorporating individual and family information. Diffusion approximations fit well to simulated results even for large selection coefficients. Methods that give much weight to family information, such as BLUP evaluation which is widely used in animal breeding, reduce fixation rates of mutant genes because of the reduced effective population sizes. In general, it is observed that even mutants with relatively small heterozygous effects (say 0.1 phenotypic standard deviation) are practically ‘safe’ (i.e. their probability of loss from one generation to the next is smaller than, say, 10%) after just a few generations, typically less than 10. For methods of selection with larger effective size, such as within-family selection, the mutant is ‘safe’ in the population somewhat earlier but eventual fixation takes a longer time. Finally we evaluate the amount by which the use of marker assisted selection reduces the fixation probability of newly arisen mutants. 相似文献
5.
Hui-juan Zhu Lin-jie Wang Xiang-qing Wang Hui Pan Nai-shi Li Hong-bo Yang Ming Jin Bao-xia Zang Feng-ying Gong 《Cytotechnology》2015,67(5):885-892
Hydroxysafflor yellow A (HSYA), a main component of safflor yellow, has been demonstrated to prevent steroid-induced avascular necrosis of femoral head by inhibiting primary bone marrow-derived mesenchymal stromal cells adipogenic differentiation induced by steroid. In this study, we investigate the effect of HSYA on the proliferation and adipogenesis of mouse 3T3-L1 preadipocytes. The effects of HSYA on proliferation and differentiation of 3T3-L1 cells and its possible mechanism were studied by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide spectrophotometry, Oil Red O staining, intracellular triglyceride assays, real-time quantitative RT-PCR, transient transfection and dual luciferase reporter gene methods. HSYA inhibited the proliferation of 3T3-L1 preadipocytes and cell viability greatly decreased in a dose and time dependent manner. HSYA (1 mg/l) notably reduced the amount of intracellular lipid and triglyceride content in adipocytes by 21.3 % (2.13 ± 0.36 vs 2.71 ± 0.40, P < 0.01) and 22.6 % (1.33 ± 0.07 vs 1.72 ± 0.07, P < 0.01) on days 8 following the differentiation, respectively. HSYA (1 mg/l) significantly increased hormone-sensitive lipase (HSL) mRNA expression and promoter activities by 2.4- and 1.55-fold, respectively (P < 0.01), in differentiated 3T3-L1 adipocytes. HSYA inhibits the proliferation and adipogenesis of 3T3-L1 preadipocytes. The inhibitory action of HYSA on adipogenesis may be due to the promotion of lipolytic-specific enzyme HSL expression by increasing HSL promoter activity. 相似文献
6.
Liu Minliang Liang Liang Liu Haofei Zhang Ming Martin Caitlin Sun Wei 《Biomechanics and modeling in mechanobiology》2019,18(2):387-398
Biomechanics and Modeling in Mechanobiology - It is well known that residual deformations/stresses alter the mechanical behavior of arteries, e.g., the pressure–diameter curves. In an effort... 相似文献
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Aisada Uchugonova Wenluo Cao Robert M Hoffman Karsten Koenig 《Cell cycle (Georgetown, Tex.)》2015,14(21):3430-3433
Hair-follicle-associated pluripotent (HAP) stem cells can differentiate into many cell types, including neurons and heart muscle cells, and have been shown to repair peripheral nerves and the spinal cord in mice. HAP stem cells can be obtained from each individual patient for regenerative medicine which overcomes problems with immune rejection. Previously, we have demonstrated that genetically-encoded protein markers such as GFP in transgenic mice can be used to visualize HAP stem cells in vivo by multiphoton tomography. Detection and visualization of stem cells in vivo without exogenous labels such as GFP would be important for human application. In the present report, we demonstrate label-free visualization of hair follicle stem cells in mouse whiskers by multiphoton tomography due to the intrinsic fluorophores such as NAD(P)H/flavins. We compared multiphoton tomography of GFP-labeled HAP stem cells and unlabeled stem cells in isolated mouse whiskers. We show that observation of HAP stem cells by label-free multiphoton tomography is comparable to detection using GFP-labeled stem cells. The results described here have important implications for detection and isolation of human HAP stem cells for regenerative medicine. 相似文献
9.
人睫状神经营养因子的原核表达,纯化及其生物效应 总被引:2,自引:0,他引:2
人睫状神经营养因子(hCNTF)克隆入pBV220中,在DH5α菌株中表达,重组蛋白以包含体的形式存在,表达量为菌体总蛋白的50%左右。经比较发现用2mol/L脲洗涤包含体可溶解大量可溶性细菌蛋白,且包含体损失较小。在高浓度变性剂条件下进行sepharcylS-200凝胶过滤,解决了纯化中hCNTF易聚合的问题,在低浓度变性剂条件下进行DEAE离子交换,有利于蛋白活性的保持。经两步纯化后得到均一性hCNTF,纯度达95%以上。在自然状态下使hCNTF复性。纯化复性后的hCNTF对无血清培养的鸡胚背根节神经元和脊髓腹角运动神经元有明显的维持存活和促进生长发育的生物效应。 相似文献
10.
The incidence of gallbladder cancer (GBC) is relatively rare but a high degree of malignancy. The migration and invasion potential of GBC severely affects the prognosis of patients with GBC. Glycochenodeoxycholate (GCDC) is one of the most important components in GBC-associated microenvironment. However, the role of GCDC in the metastatic feature of GBC cells is not fully understood. First, the results of this study found that GCDC could effectively enhance the metastasis of GBC cells. Furthermore, GCDC could lead to the enhancement of epithelial to mesenchymal transition (EMT) phenotype in GBC cells, which is concerned to be an important mechanism of tumor metastasis. Further studies showed that GCDC treatment induced the upregulation of matrix metalloproteinase-3 (MMP3), MMP9, and SOCS3/JAK2/p-STAT3 signal pathway in GBC cells, which could regulate the level of EMT. Beside that, we also found the positive expression of farnesoid X receptor (FXR) in GBC cells and inhibition of FXR could significantly block the effect of GCDC on the metastasis of GBC cells. These results indicated that GCDC promoted GBC cells metastasis by enhancing the level of EMT and inhibition of FXR could significantly block the effect of GCDC. On one hand, FXR might be an indicator for predicting the metastasis of patient with GBC. On the other hand, FXR might serve as a potential antimetastasis target in GBC therapy. 相似文献