2,898 research outputs found

    Targeting of MKRNI for identifying cancer treatment agents

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    The molecular chaperone Hsp90 binds specifically to hTERT and is required for assembly of active telomerase activity. We show that disruption of Hsp90 function gy geldanamycin efficient ubiquitination and proteasome-mediated degradation of hTERT

    Ubiquitin ligase MKRN1 modulates telomere length homeostasis through a proteolysis of hTERT

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    Telomere homeostasis is regulated by telomerase and a collection of associatedproteins. Telomerase is, in turn, regulated by post-translational modifications of the rate-limiting catalytic subunit hTERT. Here we show that disruption of Hsp90 by geldanamycin promotes efficient ubiquitination and proteasome-mediated degradation of hTERT. Furthermore, we have used the yeast two-hybrid method to identify a novel RING finger gene (MKRN1) encoding an E3 ligase that mediates ubiquitination of hTERT. Overexpression of MKRN1 in telomerase-positive cells promotes the degradation of hTERT and decreases telomerase activity and subsequently telomere length. Our data suggest that MKRN1 plays an important role in modulating telomere length homeostasis through a dynamic balance involving hTERT protein stability

    Quantum Optical Induced-Coherence Tomography by a Hybrid Interferometer

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    Quantum interferometry based on induced-coherence phenomena has demonstrated the possibility of undetected-photon measurements. Perturbation in the optical path of probe photons can be detected by interference signals generated by quantum mechanically correlated twin photons propagating through a different path, possibly at a different wavelength. To the best of our knowledge, this work demonstrates for the first time a hybrid-type induced-coherence interferometer that incorporates a Mach-Zehnder-type interferometer for visible photons and a Michelson-type interferometer for infrared photons, based on double-pass pumped spontaneous parametric down-conversion. This configuration enables infrared optical measurements via the detection of near-visible photons and provides methods for characterizing the quality of measurements by identifying photon pairs of different origins. The results verify that the induced-coherence interference visibility is approximately the same as the heralding efficiencies between twin photons along the relevant spatial modes. Applications to both time-domain and frequency-domain quantum-optical induced-coherence tomography for three-dimensional test structures are demonstrated. The results prove the feasibility of practical undetected-photon sensing and imaging techniques based on the presented structure

    Transcriptional Regulator TonEBP Mediates Oxidative Damages in Ischemic Kidney Injury

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    TonEBP (tonicity-responsive enhancer binding protein) is a transcriptional regulator whose expression is elevated in response to various forms of stress including hyperglycemia, inflammation, and hypoxia. Here we investigated the role of TonEBP in acute kidney injury (AKI) using a line of TonEBP haplo-deficient mice subjected to bilateral renal ischemia followed by reperfusion (I/R). In the TonEBP haplo-deficient animals, induction of TonEBP, oxidative stress, inflammation, cell death, and functional injury in the kidney in response to I/R were all reduced. Analyses of renal transcriptome revealed that genes in several cellular pathways including peroxisome and mitochondrial inner membrane were suppressed in response to I/R, and the suppression was relieved in the TonEBP deficiency. Production of reactive oxygen species (ROS) and the cellular injury was reproduced in a renal epithelial cell line in response to hypoxia, ATP depletion, or hydrogen peroxide. The knockdown of TonEBP reduced ROS production and cellular injury in correlation with increased expression of the suppressed genes. The cellular injury was also blocked by inhibitors of necrosis. These results demonstrate that ischemic insult suppresses many genes involved in cellular metabolism leading to local oxidative stress by way of TonEBP induction. Thus, TonEBP is a promising target to prevent AKI

    In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser

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    The remarkably high superconducting transition temperature and upper critical field of iron(Fe)-based layered superconductors, despite ferromagnetic material base, open the prospect for superconducting electronics. However, success in superconducting electronics has been limited because of difficulties in fabricating high-quality thin films. We report the growth of high-quality c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk superconductivity by using an in-situ pulsed laser deposition technique with a 248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The temperature and field dependences of the magnetization showing strong diamagnetism and transport critical current density with superior Jc-H performance are reported. These results provide necessary information for practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let

    Body Acupuncture for Nicotine Withdrawal Symptoms: A Randomized Placebo-controlled Trial

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    This study evaluated whether improvements in nicotine withdrawal symptoms (NWS), depression and anxiety are greater for body acupuncture than for sham acupuncture. Smoking volunteers from the public were randomized to receive six sessions of either real or sham acupuncture for 2 weeks. The primary outcome measure was NWS measured by the Minnesota Nicotine Withdrawal Score, and the secondary measures were scores on the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). Eighty volunteers were randomized into real acupuncture (n = 38) and sham acupuncture (n = 42) groups, of which 46 subjects (22 and 24 in the real and sham acupuncture groups, respectively) completed the treatment and the 2-week follow-up. An intention-to-treat analysis revealed that the NWS did not differ significantly between the real and sham acupuncture groups immediately after the treatment (12.2 ± 9.7 and 12.8 ± 7.7, respectively; mean ± SD) and at the 2-week follow-up (11.7 ± 10.2 and 12.6 ± 7.8). Both groups also showed similar improvements in BDI and BAI scores. These results indicate that the real acupuncture treatment tested in this trial was no more effective than sham acupuncture at reducing NWS, depression and anxiety for smoking cessation

    Notch signaling is required for maintaining stem-cell features of neuroprogenitor cells derived from human embryonic stem cells

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    <p>Abstract</p> <p>Background</p> <p>Studies have provided important findings about the roles of Notch signaling in neural development. Unfortunately, however, most of these studies have investigated the neural stem cells (NSCs) of mice or other laboratory animals rather than humans, mainly owing to the difficulties associated with obtaining human brain samples. It prompted us to focus on neuroectodermal spheres (NESs) which are derived from human embryonic stem cell (hESC) and densely inhabited by NSCs. We here investigated the role of Notch signaling with the hESC-derived NESs.</p> <p>Results</p> <p>From hESCs, we derived NESs, the <it>in-vitro </it>version of brain-derived neurospheres. NES formation was confirmed by increased levels of various NSC marker genes and the emergence of rosette structures in which neuroprogenitors are known to reside. We found that Notch signaling, which maintains stem cell characteristics of <it>in-vivo</it>-derived neuroprogenitors, is active in these hESC-derived NESs, similar to their <it>in-vivo </it>counterpart. Expression levels of Notch signaling molecules such as NICD, DLLs, JAG1, HES1 and HES5 were increased in the NESs. Inhibition of the Notch signaling by a γ-secretase inhibitor reduced rosette structures, expression levels of NSC marker genes and proliferation potential in the NESs, and, if combined with withdrawal of growth factors, triggered differentiation toward neurons.</p> <p>Conclusion</p> <p>Our results indicate that the hESC-derived NESs, which share biochemical features with brain-derived neurospheres, maintain stem cell characteristics mainly through Notch signaling, which suggests that the hESC-derived NESs could be an <it>in-vitro </it>model for <it>in-vivo </it>neurogenesis.</p

    Culture supernatant of adipose stem cells can ameliorate allergic airway inflammation via recruitment of CD4+CD25+Foxp3 T cells

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    SDS-PAGE of supernatant after ASC cultivation. Comparison of protein composition of con sup (concentrated medium for ASCs cultivation) and ASC sup (concentrated culture supernatant after ASC cultivation for 3 days) using SDS-PAGE. Thirty micrograms of each sample was loaded into an SDS-PAGE gel. After electrophoresis, the gel was stained by Coomassie Blue (M molecular marker, arrow indicated extra proteins compared to control). (PPT 370 kb
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