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991.
Embryonic stem cells (ESC) hold great potential for the treatment of liver diseases. Here, we report the differentiation of rhesus macaque ESC along a hepatocyte lineage. The undifferentiated monkey ESC line, ORMES-6, was cultured in an optimal culture condition in an effort to differentiate them into hepatocyte-like cells in vitro. The functional efficacy of the differentiated hepatic cells was evaluated using RT-PCR for the expression of hepatocyte specific genes, and Western blot analysis and immunocytochemistry for hepatic proteins such as alpha-fetoprotein (AFP), albumin and alpha1-antitrypsin (alpha1-AT). Functional assays were performed using the periodic acid schiff (PAS) reaction and ELISA. The final yield of ESC-derived hepatocyte-like cells was measured by flow cytometry for cells that were transduced with a liver-specific lentivirus vector containing the alpha1-AT promoter driving the expression of green fluorescence protein (GFP). The treatment of monkey ESC with an optimal culture condition yielded hepatocyte-like cells that expressed albumin, alpha1-AT, AFP, hepatocyte nuclear factor 3beta, glucose-6-phophatase, and cytochrome P450 genes and proteins as determined by RT-PCR and Western blot analysis. Immunofluorescent staining showed the cells positive for albumin, AFP, and alpha1-AT. PAS staining demonstrated that the differentiated cells showed hepatocyte functional activity. Albumin could be detected in the medium after 20 days of differentiation. Flow cytometry data showed that 6.5 +/- 1.0% of the total differentiated cells were positive for GFP. These results suggest that by using a specific, empirically determined, culture condition, we were able to direct monkey ESC toward a hepatocyte lineage. 相似文献
992.
Moon Seop Hyun Jong Pil Park Dongkyun Seo Sung-Jin Chang Seok Jae Lee Sang Yup Lee Kyungwon Kwak Tae Jung Park 《Bioprocess and biosystems engineering》2016,39(5):725-733
Macrocyclic carbohydrate rings were formed via enzymatic reactions around single-walled carbon nanotubes (SWNTs) as a catalyst. Cyclodextrin glucanotransferase, starch substrate and SWNTs were reacted in buffer solution to yield cyclodextrin (CD) rings wrapped around individual SWNTs. Atomic force microscopy showed the resulting complexes to be rings of 12–50 nm in diameter, which were highly soluble and dispersed in aqueous solution. They were further characterized by Raman and Fourier transform infrared spectroscopy and molecular simulation using density functional theory calculation. In the absence of SWNT, hydrogen bonding between glucose units determines the structure of maltose (the precursor of CD) and produces the curvature along the glucose chain. Wrapping SWNT along the short axis was preferred with curvature in the presence of SWNTs and with the hydrophobic interactions between the SWNTs and CD molecules. This synthetic approach may be useful for the functionalization of carbon nanotubes for development of nanostructures. 相似文献
993.
Figen Seymen Youn Jung Kim Ye Ji Lee Jenny Kang Tak-Heun Kim Hwajung Choi Mine Koruyucu Yelda Kasimoglu Elif Bahar Tuna Koray Gencay Teo Jeon Shin Hong-Keun Hyun Young-Jae Kim Sang-Hoon Lee Zang Hee Lee Hong Zhang Jan C-C. Hu James P. Simmer Eui-Sic Cho Jung-Wook Kim 《American journal of human genetics》2016,99(5):1199-1205
994.
Increased expression of OsPT1, a high-affinity phosphate transporter, enhances phosphate acquisition in rice 总被引:1,自引:0,他引:1
Seo HM Jung Y Song S Kim Y Kwon T Kim DH Jeung SJ Yi YB Yi G Nam MH Nam J 《Biotechnology letters》2008,30(10):1833-1838
Most high-affinity phosphate transporter genes (OsPTs) in rice were highly induced in roots when phosphate was depleted. OsPT1, however, was highly expressed in primary roots and leaves regardless of external phosphate concentrations. This finding was confirmed histochemically using transgenic rice plants that express the GUS reporter gene under the control of the OsPT1 promoter, which exhibited high GUS activity even in the phosphate sufficient condition. Furthermore, transgenic rice plants overexpressing the OsPT1 gene accumulated almost twice as much phosphate in the shoots as did wild-type plants. As a result, transgenic plants had more tillers than did wild-type plants, which is a typical physiological indicator for phosphate status in rice. 相似文献
995.
Hee Jung Koo Jee Eun Yang Jae Hyung Park Daekyun LeeSeung R. Paik 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(6):972-976
In this report, mutual effect of α-synuclein and GPX-1 is investigated to unveil their involvement in the PD pathogenesis in terms of cellular defense mechanism against oxidative stress. Biochemical and immunocytochemical studies showed that α-synuclein enhanced the GPX-1 activity with Kd of 17.3 nM and the enzyme in turn markedly enhanced in vitro fibrillation of α-synuclein. Transmission electron microscopy revealed the fibrillar meshwork of α-synuclein containing GPX-1 located in locally concentrated islets. The entrapped enzyme was demonstrated to be protected in a latent form and its activity was fully recovered as released from the matrix. Therefore, novel defensive roles of α-synuclein and its amyloid fibrils against oxidative stress are suggested as the GPX-1 stimulator and the active depot for the enzyme, respectively. 相似文献
996.
Regulation of the dual specificity protein phosphatase, DsPTP1, through interactions with calmodulin
Yoo JH Cheong MS Park CY Moon BC Kim MC Kang YH Park HC Choi MS Lee JH Jung WY Yoon HW Chung WS Lim CO Lee SY Cho MJ 《The Journal of biological chemistry》2004,279(2):848-858
Reversible phosphorylation is a key mechanism for the control of intercellular events in eukaryotic cells. In animal cells, Ca2+/CaM-dependent protein phosphorylation and dephosphorylation are implicated in the regulation of a number of cellular processes. However, little is known on the functions of Ca2+/CaM-dependent protein kinases and phosphatases in Ca2+ signaling in plants. From an Arabidopsis expression library, we isolated cDNA encoding a dual specificity protein phosphatase 1, which is capable of hydrolyzing both phosphoserine/threonine and phosphotyrosine residues of the substrates. Using a gel overlay assay, we identified two Ca2+-dependent CaM binding domains (CaMBDI in the N terminus and CaMBDII in the C terminus). Specific binding of CaM to two CaMBD was confirmed by site-directed mutagenesis, a gel mobility shift assay, and a competition assay using a Ca2+/CaM-dependent enzyme. At increasing concentrations of CaM, the biochemical activity of dual specificity protein phosphatase 1 on the p-nitrophenyl phosphate (pNPP) substrate was increased, whereas activity on the phosphotyrosine of myelin basic protein (MBP) was inhibited. Our results collectively indicate that calmodulin differentially regulates the activity of protein phosphatase, dependent on the substrate. Based on these findings, we propose that the Ca2+ signaling pathway is mediated by CaM cross-talks with a protein phosphorylation signal pathway in plants via protein dephosphorylation. 相似文献
997.
Jung HJ Kim PI Lee SK Lee CW Eu YJ Lee DG Earm YE Kim JI 《Biochemical and biophysical research communications》2006,340(2):633-638
GsMTx-4, a polypeptide from the spider Grammostola spatulata, is an inhibitor of mechanosensitive channels. It is known to interact with lipid membranes, suggesting it partitions into the membrane to alter the channel gating, but the effect of the membrane charge on GsMTx-4 activity remains unknown. In this study, we found that GsMTx-4 more effectively interacts with anionic lipids than zwitterionic ones. The effect of GsMTx-4 on negatively charged membranes was similar to that of the antimicrobial peptide melittin, which led us to assess GsMTx-4's antimicrobial activity. Interestingly, we found that, in contrast to other neurotoxins, GsMTx-4 exhibited antimicrobial properties and was more active against Gram-positive than Gram-negative bacteria. These results suggest that GsMTx-4 exerts its antimicrobial effect by altering the packing of the membrane and/or inhibiting mechanosensitive channels. These findings could point the way towards a new class of antimicrobial peptides. 相似文献
998.
Nan Jiang Eun-Hee Jeon Jung-Hun Pak Tae-Joung Ha In-Youl Baek Woo-Suk Jung Jai-Heon Lee Doh-Hoon Kim Hong-Kyu Choi Zheng Cui Young-Soo Chung 《Plant biotechnology reports》2010,4(4):253-260
Plant secondary metabolites have always been a focus of study due to their important roles in human medicine and nutrition. We transferred the isoflavone synthase (IFS) gene into soybean [Glycine max (L.) Merr.] using the Agrobacterium-mediated transformation method in an attempt to produce transformed soybean plants which produced increased levels of the secondary metabolite, isoflavone. Although the trial to produce transgenic plant failed due to unestablished hygromycin selection, transformed callus cell lines were obtained. The induction rate and degree of callus were similar among the three cultivars tested, but light illumination positively influenced the frequency of callus formation, resulting in a callus induction rate of 74% for Kwangan, 67% for Sojin, and 73% for Duyou. Following seven to eight subcultures on selection media, the isoflavone content of the transformed callus lines were analyzed by high-performance liquid chromatography. The total amount of isoflavone in the transformed callus cell lines was three- to sixfold higher than that in control callus or seeds. Given the many positive effects of isoflavone on human health, it may be possible to adapt our transformed callus lines for industrialization through an alternative cell culture system to produce high concentrations of isoflavones. 相似文献
999.
Je-Hoon Ryu Jace Drain Jung Hwan Kim Sean McGee Angus Gray-Weale Lynne Waddington Glendon J. Parker Mark Hargreaves Sang-Ho Yoo David Stapleton 《International journal of biological macromolecules》2009,45(5):478-482
Glycogen is a cellular energy store that is crucial for whole body energy metabolism, metabolic regulation and exercise performance. To understand glycogen structure we have purified glycogen particles from rat liver and human skeletal muscle tissues and compared their biophysical properties with those found in commercial glycogen preparations. Ultrastructural analysis of commercial liver glycogens fails to reveal the classical α-rosette structure but small irregularly shaped particles. In contrast, commercial slipper limpet glycogen consists of β-particles with similar branching and chain lengths to purified rat liver glycogen together with a tendency to form small α-particles, and suggest it should be used as a source of glycogen for all future studies requiring a substitute for mammalian liver glycogen. 相似文献
1000.
The MHC class I-like IgG receptor controls perinatal IgG transport,IgG homeostasis,and fate of IgG-Fc-coupled drugs 总被引:1,自引:0,他引:1
Roopenian DC Christianson GJ Sproule TJ Brown AC Akilesh S Jung N Petkova S Avanessian L Choi EY Shaffer DJ Eden PA Anderson CL 《Journal of immunology (Baltimore, Md. : 1950)》2003,170(7):3528-3533
Abs of the IgG isotype are efficiently transported from mother to neonate and have an extended serum t(1/2) compared with Abs of other isotypes. Circumstantial evidence suggests that the MHC class I-related protein, the neonatal FcR (FcRn), is the FcR responsible for both in vivo functions. To understand the phenotypes imposed by FcRn, we produced and analyzed mice with a defective FcRn gene. The results provide direct evidence that perinatal IgG transport and protection of IgG from catabolism are mediated by FcRn, and that the latter function is key to IgG homeostasis, essential for generating a potent IgG response to foreign Ags, and the basis of enhanced efficacy of Fc-IgG-based therapeutics. FcRn is therefore a promising therapeutic target for enhancing protective humoral immunity, treating autoimmune disease, and improving drug efficacy. 相似文献