57 research outputs found

    Nanog Prion-like Assembly Mediates Dna Bridging to Facilitate Chromatin Reorganization and Activation of Pluripotency

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    Human NANOG expression resets stem cells to ground-state pluripotency. Here we identify the unique features of human NANOG that relate to its dose-sensitive function as a master transcription factor. NANOG is largely disordered, with a C-terminal prion-like domain that phase-transitions to gel-like condensates. Full-length NANOG readily forms higher-order oligomers at low nanomolar concentrations, orders of magnitude lower than typical amyloids. Using single-molecule Förster resonance energy transfer and fluorescence cross-correlation techniques, we show that NANOG oligomerization is essential for bridging DNA elements in vitro. Using chromatin immunoprecipitation sequencing and Hi-C 3.0 in cells, we validate that NANOG prion-like domain assembly is essential for specific DNA recognition and distant chromatin interactions. Our results provide a physical basis for the indispensable role of NANOG in shaping the pluripotent genome. NANOG\u27s unique ability to form prion-like assemblies could provide a cooperative and concerted DNA bridging mechanism that is essential for chromatin reorganization and dose-sensitive activation of ground-state pluripotency

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Search for anomalous production of events with three or more leptons in pp collisions at √s = 8TeV

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.A search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5fb-1 of proton-proton collisions with center-of-mass energy s=8TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, same-flavor lepton pair (OSSF), the invariant mass of the OSSF pair, the presence or absence of a tagged bottom-quark jet, the number of identified hadronically decaying τ leptons, and the magnitude of the missing transverse energy and of the scalar sum of jet transverse momenta. The numbers of observed events are found to be consistent with the expected numbers from standard model processes, and limits are placed on new-physics scenarios that yield multilepton final states. In particular, scenarios that predict Higgs boson production in the context of supersymmetric decay chains are examined. We also place a 95% confidence level upper limit of 1.3% on the branching fraction for the decay of a top quark to a charm quark and a Higgs boson (t→cH), which translates to a bound on the left- and right-handed top-charm flavor-violating Higgs Yukawa couplings, λtcH and λctH, respectively, of |λtcH|2+|λctH|2<0.21

    Author&apos;s personal copy Single actomyosin motor interactions in skeletal muscle ☆

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    We present a study of intramuscular motion during contraction of skeletal muscle myofibrils. Myofibrillar actin was labeled with fluorescent dye so that the ratio of fluorescently labeled to unlabeled protein was 1:10 5 . Such sparse labeling assured that there was on average only one actin-marker present in the focus at a given time. From the intensity signal in the two orthogonal detection channels, significant fluctuations, similar to fluorescent burst in diffusion-based single-molecule detection schemes, were identified via a threshold algorithm and analyzed with respect to their intensity and polarization. When only rigor complexes were formed, the fluctuations of polarized intensity were characterized by unimodal Gaussian photon distributions. During contraction, in contrast, bimodal Gaussian photon distributions were observed above the rigor background threshold. This suggests that the bimodal Gaussian photon distributions represent preand post-power stroke conformations. Clusters of polarized photons indicated an anisotropy decay of single actomyosin motors of~9 s during muscle contraction. This article is part of a Special Issue entitled: 11th European Symposium on Calcium

    A novel pulsed STED microscopy method using FastFLIM and the phasor plots

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    Stimulated emission depletion (STED) microscopy is a powerful super-resolution microscopy technique that enables observation of macromolecular complexes and sub-cellular structures with spatial resolution below the diffraction limit. The spatial resolution of STED is limited by power of the depletion laser at the specimen plane. Higher depletion laser power will improve resolution, but at the cost of increased photo-bleaching, photo-toxicity, and anti-stoke emission background. This degrades the signal-to-noise ratio, and can significantly limit STED applications in living specimens. Here, we present an efficient multi-color STED microscopy method based on the digital frequency domain fluorescence lifetime imaging (FastFLIM) and the phasor plots. Our approach utilizes a combination of pulsed excitation and pulsed depletion lasers to record the time-resolved photons by FastFLIM. We demonstrate that the resolution is improved without increasing the depletion laser power by digital separation of the depleted species from the partially depleted species based on their different decay kinetics. We show the utility of this novel STED method applied in both fixed and live cellular samples, and also show its application to fluorescence lifetime correlation spectroscopy (FLCS) measurements. By combining fluorophores with different fluorescence lifetimes, we simultaneously record two-color STED images of cells labeled with Atto655 and Alexa647 in a single scan by using a single pair of excitation and depletion lasers. This novel approach shortens the data acquisition time while minimizing the photo-toxicity caused when using two separate depletion lasers

    Single actomyosin motor interactions in skeletal muscle

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    We present a study of intramuscular motion during contraction of skeletal muscle myofibrils. Myofibrillar actin was labeled with fluorescent dye so that the ratio of fluorescently labeled to unlabeled protein was 1:105. Such sparse labeling assured that there was on average only one actin-marker present in the focus at a given time. From the intensity signal in the two orthogonal detection channels, significant fluctuations, similar to fluorescent burst in diffusion-based single-molecule detection schemes, were identified via a threshold algorithm and analyzed with respect to their intensity and polarization. When only rigor complexes were formed, the fluctuations of polarized intensity were characterized by unimodal Gaussian photon distributions. During contraction, in contrast, bimodal Gaussian photon distributions were observed above the rigor background threshold. This suggests that the bimodal Gaussian photon distributions represent pre- and post-power stroke conformations. Clusters of polarized photons indicated an anisotropy decay of single actomyosin motors of ~ 9 s during muscle contraction

    Case detection and diagnosis of primary aldosteronism â The consensus of Taiwan Society of Aldosteronism

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    Background/Purpose: Even though the increasing clinical recognition of primary aldosteronism (PA) as a public health issue, its heightened risk profiles and the availability of targeted surgical/medical treatment being more understood, consensus in its diagnosis and management based on medical evidence, while recognizing the constraints of our real-world clinical practice in Taiwan, has not been reached. Methods: The Taiwan Society of Aldosteronism (TSA) Task Force acknowledges the above-mentioned issues and reached this Taiwan PA consensus at its inaugural meeting, in order to provide updated information of internationally acceptable standards, and also to incorporate our local disease characteristics into the management of PA. Results: When there is suspicion of PA, a plasma aldosterone to renin ratio (ARR) should be obtained initially. Patients with abnormal ARR will undergo confirmatory laboratory and image tests. Subtype classification with adrenal venous sampling (AVS) or NP-59 nuclear imaging, if AVS not available, to lateralize PA is recommended when patients are considered for adrenalectomy. The strengths and weaknesses of the currently available identification methods are discussed, focusing especially on result interpretation. Conclusion: With this consensus we hope to raise more awareness of PA among medical professionals and hypertensive patients in Taiwan, and to facilitate reconciliation of better detection, identification and treatment of patients with PA. Index words: Primary aldosteronism, Guideline, TAIPAI, TS

    Association of visceral adiposity and clinical outcome among patients with aldosterone producing adenoma

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    Introduction Primary aldosteronism (PA) is a common form of secondary hypertension that has significant cardiovascular events and increased prevalence of metabolic syndrome and diabetics. Although plasma aldosterone concentration is positively correlated with visceral fat area (VFA) in non-PA individuals, the role of visceral adiposity associated with clinical success after surgery is not known.Research design and methods We analyzed patients who underwent adrenalectomy for aldosterone-producing adenoma (APA) at the Taiwan PA Investigator group. VFA was calculated from the abdominal CT scan at APA diagnosis, and all patients received adrenalectomy.Results The study involved 100 consecutive patients with APA (42 males; mean age 49.3 years) matched with 41 essential hypertension (EH) patients. Patients with APA had smaller VFA (p=0.010) than their EH counterparts. Multiple linear regression analysis revealed that the duration of hypertension (p=0.007), but not plasma aldosterone, was negatively correlated with VFA in patients with APA. Logistic regression analysis showed that log VFA (OR=0.065, p&lt;0.001) and duration of hypertension before PA diagnosis (OR=0.919, p=0.011) can predict complete clinical success after adrenalectomy. Multifactor-adjusted generalized additive model demonstrated that log VFA &lt;9.2 was associated with complete cure of hypertension. Furthermore, VFA was increased at 6 months after adrenalectomy (p=0.045).Conclusions Patients with APA had smaller VFA than their EH counterparts, and VFA increased after adrenalectomy. Clinical complete cure of hypertension after surgery was associated with smaller VFA and shorter duration of hypertension at PA diagnosis, suggesting a potential interplay of visceral adiposity and aldosterone of the patients with APA
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