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排序方式: 共有270条查询结果,搜索用时 31 毫秒
181.
Yoshihiro Ojima Mark Thompson Duncan Retno Wahyu Nurhayati Masahito Taya William Martin Miller 《Experimental cell research》2013
The human myelogenous cell line, K562 has been extensively used as a model for the study of megakaryocytic (MK) differentiation, which could be achieved by exposure to phorbol 12-myristate 13-acetate (PMA). In this study, real-time PCR analysis revealed that the expression of catalase (cat) was significantly repressed during MK differentiation of K562 cells induced by PMA. In addition, PMA increased the intracellular reactive oxygen species (ROS) concentration, suggesting that ROS was a key factor for PMA-induced differentiation. PMA-differentiated K562 cells were exposed to hydrogen peroxide (H2O2) to clarify the function of ROS during MK differentiation. Interestingly, the percentage of high-ploidy (DNA content >4N) cells with H2O2 was 34.8±2.3% at day 9, and was 70% larger than that without H2O2 (21.5±0.8%). Further, H2O2 addition during the first 3 days of PMA-induced MK differentiation had the greatest effect on polyploidization. In an effort to elucidate the mechanisms of enhanced polyploidization by H2O2, the BrdU assay clearly indicated that H2O2 suppressed the division of 4N cells into 2N cells, followed by the increased polyploidization of K562 cells. These findings suggest that the enhancement in polyploidization mediated by H2O2 is due to synergistic inhibition of cytokinesis with PMA. Although H2O2 did not increase ploidy during the MK differentiation of primary cells, we clearly observed that cat expression was repressed in both immature and mature primary MK cells, and that treatment with the antioxidant N-acetylcysteine effectively blocked and/or delayed the polyploidization of immature MK cells. Together, these findings suggest that MK cells are more sensitive to ROS levels during earlier stages of maturation. 相似文献
182.
Tri Komala Sari Suzanne M. Pritchard Cristina W. Cunha George A. Wudiri Elizabeth I. Laws Hector C. Aguilar Naomi S. Taus Anthony V. Nicola 《Journal of virology》2013,87(24):13922-13926
Herpes simplex virus (HSV) proteins specifically required for endocytic entry but not direct penetration have not been identified. HSVs deleted of gE, gG, gI, gJ, gM, UL45, or Us9 entered cells via either pH-dependent or pH-independent endocytosis and were inactivated by mildly acidic pH. Thus, the required HSV glycoproteins, gB, gD, and gH-gL, may be sufficient for entry regardless of entry route taken. This may be distinct from entry mechanisms employed by other human herpesviruses. 相似文献
183.
Reverse micelles are formed in apolar solvents by spontaneous aggregation of surfactants. Surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) is most often used for the reverse micellar extraction of enzymes. However, the inactivation of enzyme due to strong interaction with AOT molecules is a severe problem. To overcome this problem, the AOT/water/isooctane reverse micellar system was modified by adding short chain polyethylene glycol 400 (PEG 400). The modified AOT reverse micellar system was used to extract Mucor javanicus lipase from the aqueous phase to the reverse micellar phase. The extraction efficiency (E) increased with the increase in PEG 400 addition and the maximum E in PEG 400 modified system was twofold higher than that in the PEG 400-free system. Upon addition of PEG 400, the water activity (a(w)) of aqueous phase decreased, whereas a(w) of reverse micellar phase increased. The circular dichroism spectroscopy analysis revealed that PEG 400 changes the secondary and tertiary structure of lipase. The maximum specific activity of lipase extracted in PEG 400-modified reverse micellar system was threefold higher than that in the PEG-free system. 相似文献
184.
185.
Angiogenesis, the process by which new blood vessels are formed is critical for embryonic development and physiological functioning of normal tissues. Angiogenesis also plays a critical role in the pathology of many diseases including cancer, wherein the supply and demand for blood vessels determines the rate of cancer growth. A number of therapeutic strategies are being developed to inhibit pathological angiogenesis. Kringle domains of plasminogen such as kringle 5 (K5) and a proteolytic fragment of collagen type XVIII (endostatin) are well-characterized, potent angiogenesis inhibitors. These inhibitors activate different intracellular signaling pathways to induce apoptosis and inhibit cell proliferation. Recent studies from our group have shown that K5 and endostatin can also induce autophagy in addition to apoptosis in endothelial cells. A common feature of the two treatments was the upregulation of Beclin 1 levels leading to alterations in the Beclin 1-Bcl-2 complex. Angiogenesis inhibitor-induced autophagy in endothelial cells was independent of nutritional or hypoxic stress and initiated even in the presence of endothelial-specific survival factors such as vascular endothelial growth factor (VEGF). Interfering with the autophagic response by knocking down Beclin 1 levels dramatically increased apoptosis of endothelial cells. These findings identify the autophagic response as a novel target for enhancing the therapeutic efficacy of angiogenesis inhibitors. 相似文献
186.
Wiloso Edi Iswanto Nazir Novizar Hanafi Jessica Siregar Kiman Harsono Soni Sisbudi Setiawan Arief Ameir Rahman Muryanto Romli Muhammad Utama Nuki Agya Shantiko Bayuni Jupesta Joni Utomo Tri Hendro Atmoko Sari Ajeng Arum Saputra Sharah Yunihar Fang Kai 《The International Journal of Life Cycle Assessment》2019,24(3):386-396
The International Journal of Life Cycle Assessment - This paper presents a review of the research and application of life cycle assessment (LCA) in Indonesia over the last 20 years and... 相似文献
187.
Jae Yong Yoo Ki Seong Ko Hyun-Kyeong Seo Seongha Park Wahyu Indra Duwi Fanata Rikno Harmoko Nirmal Kumar Ramasamy Thiyagarajan Thulasinathan Tesfaye Mengiste Jae-Min Lim Sang Yeol Lee Kyun Oh Lee 《The Journal of biological chemistry》2015,290(27):16560-16572
The most abundant N-glycan in plants is the paucimannosidic N-glycan with core β1,2-xylose and α1,3-fucose residues (Man3XylFuc(GlcNAc)2). Here, we report a mechanism in Arabidopsis thaliana that efficiently produces the largest N-glycan in plants. Genetic and biochemical evidence indicates that the addition of the 6-arm β1,2-GlcNAc residue by N-acetylglucosaminyltransferase II (GnTII) is less effective than additions of the core β1,2-xylose and α1,3-fucose residues by XylT, FucTA, and FucTB in Arabidopsis. Furthermore, analysis of gnt2 mutant and 35S:GnTII transgenic plants shows that the addition of the 6-arm non-reducing GlcNAc residue to the common N-glycan acceptor GlcNAcMan3(GlcNAc)2 inhibits additions of the core β1,2-xylose and α1,3-fucose residues. Our findings indicate that plants limit the rate of the addition of the 6-arm GlcNAc residue to the common N-glycan acceptor as a mechanism to facilitate formation of the prevalent N-glycans with Man3XylFuc(GlcNAc)2 and (GlcNAc)2Man3XylFuc(GlcNAc)2 structures. 相似文献
188.
189.
McFarland AP Savan R Wagage S Addison A Ramakrishnan K Karwan M Duong T Young HA 《PloS one》2011,6(2):e16967
Background
There have been conflicting reports of the role of Type I interferons (IFN) in inflammatory bowel disease (IBD). Clinical trials have shown potent efficacy of systemic interferon-beta (IFN-β) in inducing remission of ulcerative colitis. Likewise, IFNAR1−/− mice display an increased sensitivity to dextran sulfate sodium (DSS)-induced colitis, suggesting Type I IFN play a protective role during inflammation of the gut. Curiously, however, there have also been reports detailing the spontaneous development of IBD in patients receiving systemic IFN-β therapy for multiple sclerosis or hepatitis.Methodology/Principal Findings
To investigate the effects of local administration of IFN-β on a murine model of colitis, we developed a transgenic Lactobacillus acidophilus strain that constitutively expresses IFN-β (La-IFN-β). While pretreatment of mice with control Lactobacillus (La-EV) provided slight protective benefits, La-IFN-β increased sensitivity to DSS. Analysis showed colitic mice pretreated with La-IFN-β had increased production of TNF-α, IFN-γ, IL-17A and IL-13 by intestinal tissues and decreased regulatory T cells (Tregs) in their small intestine. Examination of CD103+ dendritic cells (DCs) in the Peyer''s patches revealed that IFNAR1 expression was dramatically reduced by La-IFN-β. Similarly, bone marrow-derived DCs matured with La-IFN-β experienced a 3-fold reduction of IFNAR1 and were impaired in their ability to induce Tregs.Conclusions/Significance
Our IFNAR1 expression data identifies a correlation between the loss/downregulation of IFNAR1 on DCs and exacerbation of colitis. Our data show that Lactobacillus secreting IFN-β has an immunological effect that in our model results in the exacerbation of colitis. This study underscores that the selection of therapeutics delivered by a bacterial vehicle must take into consideration the simultaneous effects of the vehicle itself. 相似文献190.