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排序方式: 共有288条查询结果,搜索用时 15 毫秒
31.
Sungbong Kim Hyeong Ryeol Kim Hyun Ju Oh Kyu-Tae Lee Youngsoon Um Dong Wook Kim Sang Woo Seo Chulhwan Park Seung Wook Kim 《Global Change Biology Bioenergy》2023,15(5):731-742
Xylose-rich undefined broth, extracted from the dilute acid pretreatment wastes of barley straw, serves as resourceful media for Acremonium chrysogenum M35 culture and production of cephalosporin C (CPC). Concentrating the extract with proper reprocessing enables to prepare various concentrations of xylose broth (2%–8%). The undefined xylose media were prepared for CPC production from A. chrysogenum M35 by the addition of other nutrients. Cell growth and CPC production were the most effective at 6% xylose and additional 2% glycerol, with maximum CPC production of 9.07 g/L after 6 days, which is higher production than that in defined media prepared with laboratory-level nutrients and reagents. Investigation of autotrophic and reverse trans-sulfuration pathways for cysteine synthesis, a limited element of three precursors for CPC synthesis, supports the enhanced CPC production in undefined media. Abundance of xylose ensures a maintained NADPH concentration required for sulfate reduction and synthesis of amino sulfide such as cysteine. Cystathionine-γ-lyase activity profiling indicated more efficient biosynthesis in undefined media than in other cultures use glycerol and glucose, and the biosynthesis pathway of CPC production by the cephalosporin gene cluster (i.e. pcbC and cefG genes) was investigated. The process using undefined xylose media was designed, and process simulation program confirmed our results. 相似文献
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33.
Zinc-finger nucleases (ZFNs) and TAL-effector nucleases (TALENs) are powerful tools for creating genetic modifications in eukaryotic cells and organisms. But wild-type and mutant cells that contain genetic modifications induced by these programmable nucleases are often phenotypically indistinguishable, hampering isolation of mutant cells. Here we show that transiently transfected episomal reporters encoding fluorescent proteins can be used as surrogate genes for the efficient enrichment of endogenous gene-modified cells by flow cytometry. 相似文献
34.
Alpha-fetoprotein impairs APC function and induces their apoptosis 总被引:19,自引:0,他引:19
Um SH Mulhall C Alisa A Ives AR Karani J Williams R Bertoletti A Behboudi S 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(3):1772-1778
alpha-Fetoprotein (AFP) is a tumor-associated Ag, and its serum level is elevated in patients with hepatocellular carcinoma (HCC). In vitro, AFP induces functional impairment of dendritic cells (DCs). This was demonstrated by the down-regulation of CD40 and CD86 molecules and the impairment of allostimulatory function. Also, AFP was found to induce significant apoptosis of DCs, and AFP-treated DCs produced low levels of IL-12 and TNF-alpha, a cytokine pattern that could hamper an efficient antitumor immune response. Ex vivo, APCs of patients with HCC and high levels of AFP produced lower levels of TNF-alpha than that of healthy individuals. In conclusion, these results illustrate that AFP induces dysfunction and apoptosis of APCs, thereby offering a mechanism by which HCC escapes immunological control. 相似文献
35.
A major challenge in clinical diagnostics and environmental analysis is the difficulty in rapid and sensitive detection of multiple target molecules simultaneously (i.e., multiplexed detections). Our group has designed and synthesized a dendrimer-like DNA (DL-DNA) that is multivalent and anisotropic; using this unique DNA structure, we have developed a fluorescence-tagged nanobarcode system for multiplex detection. This nanobarcode system allows the rapid and sensitive detection of multiple pathogens simultaneously using the ratios of two different fluorescent dyes, green and red, with which different DL-DNAs are labeled. The key step of our nanobarcode model lies in the monodisperse preparation of DL-DNA. Two methods, solution phase and solid phase, are presented here. With slight modifications, this platform technology can also be extended to the multiplexed detection of RNA and proteins. This protocol can be completed in 2-5 d. 相似文献
36.
Su-Jin Kim Jeong-Han Lee Beom-Su Kim Hong-Seob So Raekil Park Noh-Yil Myung Jae-Young Um Seung-Heon Hong 《PloS one》2012,7(9)
Excessive nitric oxide (NO) production is toxic to the cochlea and induces hearing loss. However, the mechanism through which NO induces ototoxicity has not been completely understood. The aim of this study was to gain further insight into the mechanism mediating NO-induced toxicity in auditory HEI-OC1 cells and in ex vivo analysis. We also elucidated whether and how epigallocatechin-3-gallate (EGCG), the main component of green tea polyphenols, regulates NO-induced auditory cell damage. To investigate NO-mediated ototoxicity, S-nitroso-N-acetylpenicillamine (SNAP) was used as an NO donor. SNAP was cytotoxic, generating reactive oxygen species, releasing cytochrome c, and activating caspase-3 in auditory cells. NO-induced ototoxicity also mediated the nuclear factor (NF)-κB/caspase-1 pathway. Furthermore, SNAP destroyed the orderly arrangement of the 3 outer rows of hair cells in the basal, middle, and apical turns of the organ of Corti from the cochlea of Sprague–Dawley rats at postnatal day 2. However, EGCG counteracted this ototoxicity by suppressing the activation of caspase-3/NF-κB and preventing the destruction of hair cell arrays in the organ of Corti. These findings may lead to the development of a model for pharmacological mechanism of EGCG and potential therapies against ototoxicity. 相似文献
37.
Kyu-Bong Kim Myeon Woo Chung So Young Um Ji Seon Oh Seon Hwa Kim Mi Ae Na Hye Young Oh Wan-Seob Cho Ki Hwan Choi 《Metabolomics : Official journal of the Metabolomic Society》2008,4(4):377-392
The primary objective of this study was to discover biomarkers which are correlated with hepatotoxicity induced by chemicals
using 1H NMR spectral data of urine. A procedure of nuclear magnetic resonance (NMR) urinalysis using pattern recognition was proposed
for early screening of the hepatotoxicity of CCl4, acetaminophen (AAP), and d-galactosamine (GalN) in rats. The hepatotoxic compounds were expected to induce necrosis in hepatocytes. This was confirmed
through blood biochemistry and histopathology. CCl4 (1 ml/kg, po) or GalN (0.8 g/kg, ip) was single administered to Sprague–Dawley (S–D) rats and urine was collected every 24 h.
Animals were sacrificed 24 h or 48 h post-dosing. AAP (2 g/kg, po) was administered for 2 days and then the animals were sacrificed
24 h after the last treatment. NMR spectroscopy revealed evidently different clustering between control groups and hepatotoxicant
treatment groups in global metabolic profilings as indicated by partial least square (PLS)-discrimination analysis (DA). In
targeted profilings, endogenous metabolites of allantoin, citrate, taurine, 2-oxoglutarate, acetate, lactate, phenylacetyl
glycine, succinate, phenylacetate, 1-methylnicotinamide, hippurate, and benzoate were selected as putative biomarkers for
hepatoxicity by CCl4, AAP, and GalN. Comparison of our rat 1H NMR PLS-DA data with histopathological changes suggests that 1H NMR urinalysis can be used to predict hepatotoxicity induced by CCl4, AAP, and GalN. 相似文献
38.
In animals, β-carotene 15,15′-monooxygenase (BCMO) is the key enzyme involved in the metabolism of plant β-carotene to retinal.
In the present study, we utilized β-carotene-producing Escherichia coli to screen for mutants with higher BCMO activity which was monitored by color changes derived from β-carotene cleavage. Recombinant
wild-type and T381L mutant BCMO proteins were purified to near homogeneity in E. coli, and their enzymatic activities were determined by HPLC analysis. The catalytic efficiency for β-carotene and retinal production
of the mutant were 1.5-fold and 1.7-fold higher than those of wild-type, respectively. Further BCMO function in mammalian
cells was analyzed by a retinoic acid receptor reporter assay, which responds to the metabolic conversion of β-carotene to
retinoic acid in vivo. Overall, these tools can be used to screen more active BCMO for the industrial and pharmacological
purpose of retinal production from β-carotene. 相似文献
39.
40.
Choi IY Kim SJ Jeong HJ Park SH Song YS Lee JH Kang TH Park JH Hwang GS Lee EJ Hong SH Kim HM Um JY 《Molecular and cellular biochemistry》2007,305(1-2):153-161
The citrus unshiu peel has been used traditionally as a medicine to improve bronchial and asthmatic conditions or cardiac
and blood circulation in Korea, China, and Japan. Here, we report the effects of citrus unshiu peel water extract (CPWE) on
the phorbol myristate acetate (PMA) + calcium ionophore A23187-induced hypoxia-inducible factor-1α (HIF-1α) activation and
inflammatory cytokine production from the human mast cell line, HMC-1 cells. We compared CPWE with hesperidin, a common constituent
of citrus unshiu. CPWE and hesperidin inhibited the PMA + A23187-induced HIF-1α expression and the subsequent production of
vascular endothelial growth factor (VEGF). In addition, CPWE suppressed PMA + A23187-induced phosphorylation of the extracellular
signal-regulated kinase (ERK). We also show that the increased cytokines interleukin (IL)-1β, IL-8, and tumor necrosis factor
(TNF)-α level was significantly inhibited by treatment of CPWE or hesperidin. In the present study, we report that CPWE and
hesperidin are inhibitors of HIF-1α and cytokines on the mast cell-mediated inflammatory responses. 相似文献