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991.
Youn Wook Chung Daewon Jeong Ok Jeong Noh Yong Hwan Park Soo Im Kang Min Goo Lee Tae-Hoon Lee Moon Bin Yim Ick Young Kim 《Molecules and cells》2009,27(5):609-613
It has been reported that selenoprotein W (SelW) mRNA is highly expressed in the developing central nerve system of rats,
and its expression is maintained until the early postnatal stage. We here found that SelW protein significantly increased
in mouse brains of postnatal day 8 and 20 relative to embryonic day 15. This was accompanied by increased expression of SOD1
and SOD2. When the expression of SelW in primary cultured cells derived from embryonic cerebral cortex was knocked down with
small interfering RNAs (siRNAs), SelW siRNA-transfected neuronal cells were more sensitive to the oxidative stress induced
by treatment of H2O2 than control cells. TUNEL assays revealed that H2O2-induced apoptotic cell death occurred at a higher frequency in the siRNA-transfected cells than in the control cells. Taken
together, our findings suggest that SelW plays an important role in protection of neurons from oxidative stress during neuronal
development. 相似文献
992.
993.
Minglei Tian Hongyuan Yan Kyung Ho Row 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(8-9):738-742
New ionic liquid-modified silica sorbents were developed by the surface chemical modification of the commercial silica using synthesized ionic liquids. The obtained ionic liquid-modified particles were successfully used as a special sorbent in solid-phase extraction process to isolation of cryptotanshinone, tanshinone I and tanshinone IIA from Salvia Miltiorrhiza Bunge. Different washing and elution solvents such as water, methanol and methanol–acetic acid (90/10, v/v) were evaluated. A comparison of ionic liquid-modified silica cartridges and traditional silica cartridge show that higher recovery was observed using ionic liquid-modified silica sorbents. A quantitative analysis was conducted by high-performance liquid chromatography using a C18 column (5 μm, 150 mm × 4.6 mm) with methanol–water (78:22, v/v, and containing 0.5% acetic acid) as a mobile phase. Good linearity was obtained from 0.5 × 10?4 to 0.5 mg/mL (r2 > 0.999) with the relative standard deviations less than 4.8%. 相似文献
994.
Kyung Mee Kim George N. Henderson Reginald F. Frye Cheryl D. Galloway Nancy J. Brown Mark S. Segal Witcha Imaram Alexander Angerhofer Richard J. Johnson 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(1-2):65-70
Uric acid (UA) can be directly converted to allantoin enzymatically by uricase in most mammals except humans or by reaction with superoxide. UA can react directly with nitric oxide to generate 6-aminouracil and with peroxynitrite to yield triuret; both of these metabolites have been identified in biological samples. We now report a validated high-performance liquid chromatography and tandem mass spectrometry method for the determination of these urinary UA metabolites. Urine samples were diluted 10-fold, filtered and directly injected onto HPLC for LC–MS/MS analysis. The urinary metabolites of UA were separated using gradient HPLC. Identification and quantification of UA urinary metabolites was performed with electrospray in positive ion mode by selected-reaction monitoring (SRM). Correlation coefficients were 0.991–0.999 from the calibration curve. The intra- and inter-day precision (R.S.D., %) of the metabolites ranged from 0.5% to 13.4% and 2.5–12.2%, respectively. In normal individuals (n = 21), urinary allantoin, 6-aminouracil and triuret, were 15.30 (±8.96), 0.22 (±0.12), and 0.12 (±0.10) μg/mg of urinary creatinine (mean (±S.D.)), respectively. The new method was used to show that smoking, which can induce oxidative stress, is associated with elevated triuret levels in urine. Thus, the method may be helpful in identifying pathways of oxidative stress in biological samples. 相似文献
995.
Byoung Chan Kim Daniel Lopez‐Ferrer Sang‐Mok Lee Hye‐Kyung Ahn Sujith Nair Seong H. Kim Beom Soo Kim Konstantinos Petritis David G. Camp Jay W. Grate Richard D. Smith Yoon‐Mo Koo Man Bock Gu Professor Jungbae Kim Professor 《Proteomics》2009,9(7):1893-1900
A stable and robust trypsin‐based biocatalytic system was developed and demonstrated for proteomic applications. The system utilizes polymer nanofibers coated with trypsin aggregates for immobilized protease digestions. After covalently attaching an initial layer of trypsin to the polymer nanofibers, highly concentrated trypsin molecules are crosslinked to the layered trypsin by way of a glutaraldehyde treatment. This process produced a 300‐fold increase in trypsin activity compared with a conventional method for covalent trypsin immobilization, and proved to be robust in that it still maintained a high level of activity after a year of repeated recycling. This highly stable form of immobilized trypsin was resistant to autolysis, enabling repeated digestions of BSA over 40 days and successful peptide identification by LC‐MS/MS. This active and stable form of immobilized trypsin was successfully employed in the digestion of yeast proteome extract with high reproducibility and within shorter time than conventional protein digestion using solution phase trypsin. Finally, the immobilized trypsin was resistant to proteolysis when exposed to other enzymes (i.e., chymotrypsin), which makes it suitable for use in “real‐world” proteomic applications. Overall, the biocatalytic nanofibers with trypsin aggregate coatings proved to be an effective approach for repeated and automated protein digestion in proteomic analyses. 相似文献
996.
Elucidating native structure–function relationships of proteins identified using PAGE has been impeded by limitations in the isolation of intact proteins from the gel. By hydrolyzing polyacrylamide gel band under mildly acidic conditions rather than digesting entrapped proteins ~70% of a large native protein, mouse IgG1 (molecular weight 150 kDa), was isolated. Further analysis indicated that the isolated antibodies had preserved specific binding capability to target antigens as well as intact molecular weights. This new technology may contribute to functional proteomic studies through the isolation of proteins in their native state after PAGE, and other technologies requiring simultaneous separation and isolation of other macromolecules and complexes. 相似文献
997.
Prokaryotic type II and type III pantothenate kinases: The same monomer fold creates dimers with distinct catalytic properties 总被引:3,自引:0,他引:3
Hong BS Yun MK Zhang YM Chohnan S Rock CO White SW Jackowski S Park HW Leonardi R 《Structure (London, England : 1993)》2006,14(8):1251-1261
Three distinct isoforms of pantothenate kinase (CoaA) in bacteria catalyze the first step in coenzyme A biosynthesis. The structures of the type II (Staphylococcus aureus, SaCoaA) and type III (Pseudomonas aeruginosa, PaCoaA) enzymes reveal that they assemble nearly identical subunits with actin-like folds into dimers that exhibit distinct biochemical properties. PaCoaA has a fully enclosed pantothenate binding pocket and requires a monovalent cation to weakly bind ATP in an open cavity that does not interact with the adenine nucleotide. Pantothenate binds to an open pocket in SaCoaA that strongly binds ATP by using a classical P loop architecture coupled with specific interactions with the adenine moiety. The PaCoaA*Pan binary complex explains the resistance of bacteria possessing this isoform to the pantothenamide antibiotics, and the similarity between SaCoaA and human pantothenate kinase 2 explains the molecular basis for the development of the neurodegenerative phenotype in three mutations in the human protein. 相似文献
998.
There are a growing number of globally approved products and clinical trials utilizing autologous and allogeneic therapeutic cells for applications in regenerative medicine and immunotherapies. However, there is a need to develop rapid and cost-effective methods for manufacturing therapeutically effective cells. Furthermore, the resulting manufactured cells may exhibit heterogeneities that result in mixed therapeutic outcomes. Engineering approaches that can provide distinct microenvironmental cues to these cells may be able to enhance the growth and characterization of these cell products. This mini-review describes strategies to potentially enhance the expansion of therapeutic cells with biomaterials and bioreactors, as well as to characterize the cell products with microphysiological systems. These systems can provide distinct cues to maintain the quality attributes of the cells and evaluate their function in physiologically relevant conditions. 相似文献
999.
1000.
Dong Eun Lee Nam Joo Kang Kyung Mi Lee Bo Kyung Lee Jong Hun Kim Ki Won Lee Hyong Joo Lee 《The Journal of nutritional biochemistry》2010,21(8):680-686
Cocoa, a good source of dietary antioxidative polyphenols, exhibited anticarcinogenic activity in animal models, but the molecular mechanisms of the chemopreventive potential of cocoa remain unclear. Inhibition of gap-junction intercellular communication (GJIC) is strongly related to tumorigenesis. Cocoa polyphenol extracts (CPE) dose dependently attenuated hydrogen peroxide (H2O2)-induced inhibition of GJIC in rat liver epithelial (RLE) cells. CPE inhibited the H2O2-induced phosphorylation and internalization of connexin 43, which is a regulating protein of GJIC in RLE cells. The H2O2-induced accumulation of reactive oxygen species and activation of extracellular signal-regulated kinase were inhibited by CPE treatment. However, CPE did not block H2O2-induced phosphorylation of p38 mitogen-activated protein kinase. An ex vivo kinase assay demonstrated that CPE inhibited the H2O2-induced mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) 1 activity in RLE cell lysates. Ex vivo pull-down assay data revealed that CPE directly bound with MEK1 to inhibit MEK1 activity. These results indicate that CPE protects against the H2O2-induced inhibition of GJIC through antioxidant activity and direct inhibition of MEK activity, which may contribute to its chemopreventive potential. 相似文献