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https://www.readbyqxmd.com/read/29156586/in-depth-glyco-peptidomics-approach-reveals-unexpected-diversity-of-glycosylated-peptides-and-atypical-post-translational-modifications-in-dendroaspis-angusticeps-snake-venom
#1
Michel Degueldre, Julien Echterbille, Nicolas Smargiasso, Christian Damblon, Charlotte Gouin, Gilles Mourier, Nicolas Gilles, Edwin De Pauw, Loïc Quinton
Animal venoms represent a valuable source of bioactive peptides that can be derived into useful pharmacological tools, or even innovative drugs. In this way, the venom of Dendroaspis angusticeps (DA), the Eastern Green Mamba, has been intensively studied during recent years. It mainly contains hundreds of large toxins from 6 to 9 kDa, each displaying several disulfide bridges. These toxins are the main target of venom-based studies due to their valuable activities obtained by selectively targeting membrane receptors, such as ion channels or G-protein coupled receptors...
November 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29156380/structure-based-design-of-herg-neutral-antihypertensive-oxazalone-and-imidazolone-derivatives
#2
Busecan Aksoydan, Isik Kantarcioglu, Ismail Erol, Ramin Ekhteiari Salmas, Serdar Durdagi
Angiotensin II receptor type 1 (AT1) antagonists are the most recent drug class against hypertension. Recently first crystal structure of AT1 receptor is deposited to the protein data bank (PDB ID: 4YAY). In this work, several molecular screening methods such as molecular docking and de novo design studies were performed and it is found that oxazolone and imidazolone derivatives reveal similar/better interaction energy profiles compared to the FDA approved sartan molecules at the binding site of the AT1 receptor...
October 18, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/29156125/validating-coarse-grained-voltage-activation-model-by-comparing-the-performance-to-the-results-of-mc-simulations
#3
Myungjin Lee, Vesselin Kolev, Arieh Warshel
Simulating the nature of voltage activated systems is a problem of major current interest, covering the action of voltage gated ion channels to energy storage batteries. However, fully microscopic converging molecular simulations of external voltage effects present a major challenge and macroscopic models are associated with major uncertainties about the dielectric treatment and the underlying physical basis. Recently we developed a coarse grained (CG) model that represents explicit the electrodes, the electrolytes and the membrane / protein system...
November 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29155787/synthesis-of-core-shell-lanthanide-doped-upconversion-nanocrystals-for-cellular-applications
#4
Xiangzhao Ai, Linna Lyu, Jing Mu, Ming Hu, Zhimin Wang, Bengang Xing
Lanthanide-doped upconversion nanocrystals (UCNs) have attracted much attention in recent years based on their promising and controllable optical properties, which allow for the absorption of near-infrared (NIR) light and can subsequently convert it into multiplexed emissions that span over a broad range of regions from the UV to the visible to the NIR. This article presents detailed experimental procedures for high-temperature co-precipitation synthesis of core-shell UCNs that incorporate different lanthanide ions into nanocrystals for efficiently converting deep-tissue penetrable NIR excitation (808 nm) into a strong blue emission at 480 nm...
November 10, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29155589/the-reaction-mechanism-of-isopentenyl-phosphate-kinase-a-qm-mm-study
#5
James McClory, David J Timson, Warispreet Singh, Jian Zhang, Meilan Huang
Isopentenyl phosphate kinase (IPK) catalyzes the Mg2+-ATP dependent phosphorylation reactions to produce isopentenyl diphosphate, an important precursor in the synthesis of isopentenols. However, the position of the divalent metal ion in the crystal structures of IPK in complex with ATP and its native substrate IP has not been definitively resolved, and as a result ambiguity surrounds the catalytic mechanism of IP, limiting its exploitation as a biofuel and in drug design. Here we report the conformational change caused by substrate binding and the catalytically competent structure in complex with the metal ion Mg2+ using molecular dynamic simulations and density functional theory-based quantum mechanics/molecular mechanics calculations (B97d/AMBER99)...
November 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29155210/transition-from-androgenic-to-neurosteroidal-action-of-5%C3%AE-androstane-3%C3%AE-17%C3%AE-diol-through-the-type-a-%C3%AE-aminobutyric-acid-receptor-in-prostate-cancer-progression
#6
Ding Xia, Doan V Lai, Weijuan Wu, Zachary D Webb, Qing Yang, Lichao Zhao, Zhongxin Yu, Jessica E Thorpe, Bryan C Disch, Michael A Ihnat, Muralidharan Jayaraman, Danny N Dhanasekaran, Kelly L Stratton, Michael S Cookson, Kar-Ming Fung, Hsueh-Kung Lin
Androgen ablation is the standard of care prescribed to patients with advanced or metastatic prostate cancer (PCa) to slow down disease progression. Unfortunately, a majority of PCa patients under androgen ablation progress to castration-resistant prostate cancer (CRPC). Several mechanisms including alternative intra-prostatic androgen production and androgen-independent androgen receptor (AR) activation have been proposed for CRPC progression. Aldo-keto reductase family 1 member C3 (AKR1C3), a multi-functional steroid metabolizing enzyme, is specifically expressed in the cytoplasm of PCa cells; and positive immunoreactivity of the type A γ-aminobutyric acid receptor (GABAAR), an ionotropic receptor and ligand-gated ion channel, is detected on the membrane of PCa cells...
November 15, 2017: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/29154951/regulation-of-neural-ion-channels-by-muscarinic-receptors
#7
REVIEW
David A Brown
The excitable behaviour of neurons is determined by the activity of their endogenous membrane ion channels. Since muscarinic receptors are not themselves ion channels, the acute effects of muscarinic receptor stimulation on neuronal function are governed by the effects of the receptors on these endogenous neuronal ion channels. This review considers some principles and factors determining the interaction between subtypes and classes of muscarinic receptors with neuronal ion channels, and summarizes the effects of muscarinic receptor stimulation on a number of different channels, the mechanisms of receptor - channel transduction and their direct consequences for neuronal activity...
November 15, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/29154907/an-integrated-mathematical-epithelial-cell-model-for-airway-surface-liquid-regulation-by-mechanical-forces
#8
Dan Wu, Richard C Boucher, Brian Button, Timothy Elston, Ching-Long Lin
A robust method based on reverse engineering was utilized to construct the ion-channel conductance functions for airway epithelial sodium channels (ENaC), the cystic fibrosis transmembrane conductance regulator (CFTR), and calcium-activated chloride channels (CaCC). The ion-channel conductance models for both normal (NL) and cystic fibrosis (CF) airway epithelia were developed and then coupled to an adenosine triphosphate (ATP) metabolism model and a fluid transport model (collectively called the integrated cell model) to investigate airway surface liquid (ASL) volume regulation and hence mucus concentration, by mechanical forces in NL and CF human airways...
November 15, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/29154289/subjective-reality-and-brain-topology-inversion-transformations-on-non-orientable-atomic-surfaces-of-membrane-channels
#9
Gustav Bernroider
Subject-object relations reflect the relation of phenomenology and physics and are at the centre of interest in brain research and neuro-psychology. The unresolved dichotomy behind this relation is one of the most challenging questions of our time. Setting out from causal modelling I suggest a particular topology for subject-object relations and argue that we can find a physical realization in living organism that provides a continuous transform between both domains. In a geometrical metaphor this transform has the topological properties of a one-sided surface or non-orientable flat...
November 14, 2017: Journal of Integrative Neuroscience
https://www.readbyqxmd.com/read/29153987/development-and-characterization-of-a-human-and-mouse-intestinal-epithelial-cell-monolayer-platform
#10
Kenji Kozuka, Ying He, Samantha Koo-McCoy, Padmapriya Kumaraswamy, Baoming Nie, Karen Shaw, Priscilla Chan, Michael Leadbetter, Limin He, Jason G Lewis, Ziyang Zhong, Dominique Charmot, Marwan Balaa, Andrew J King, Jeremy S Caldwell, Matthew Siegel
We describe the development and characterization of a mouse and human epithelial cell monolayer platform of the small and large intestines, with a broad range of potential applications including the discovery and development of minimally systemic drug candidates. Culture conditions for each intestinal segment were optimized by correlating monolayer global gene expression with the corresponding tissue segment. The monolayers polarized, formed tight junctions, and contained a diversity of intestinal epithelial cell lineages...
November 7, 2017: Stem Cell Reports
https://www.readbyqxmd.com/read/29152628/highly-efficient-gas-phase-reactivity-of-protonated-pyridine-radicals-with-propene
#11
Cameron C Bright, Matthew B Prendergast, Patrick D Kelly, James P Bezzina, Stephen J Blanksby, Gabriel da Silva, Adam J Trevitt
Small nitrogen containing heteroaromatics are fundamental building blocks for many biological molecules, including the DNA nucleotides. Pyridine, as a prototypical N-heteroaromatic, has been implicated in the chemical evolution of many extraterrestrial environments, including the atmosphere of Titan. This paper reports on the gas-phase ion-molecule reactions of the three dehydro-N-pyridinium radical cation isomers with propene. Photodissociation ion-trap mass spectrometry experiments are used to measure product branching ratios and reaction kinetics...
November 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29150934/the-current-status-and-perspectives-regarding-the-clinical-implication-of-intracellular-calcium-in-breast-cancer
#12
REVIEW
Amir Tajbakhsh, Alireza Pasdar, Mehdi Rezaee, Mostafa Fazeli, Saman Soleimanpour, Seyed Mahdi Hassanian, Zahra FarshchiyanYazdi, Tayebe Younesi Rad, Gordon A Ferns, Amir Avan
Calcium ions (Ca(2+) ) act as second messengers in intracellular signaling. Ca(2+) pumps, channels, sensors, and calcium binding proteins, regulate the concentrations of intracellular Ca(2+) as a key regulator of important cellular processes such as gene expression, proliferation, differentiation, DNA repair, apoptosis, metastasis, and hormone secretion. Intracellular Ca(2+) also influences the functions of several organelles, that include: the endoplasmic reticulum, mitochondria, the Golgi, and cell membrane both in normal and breast cancer cells...
November 18, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/29150520/dopaminergic-neurotoxins-induce-cell-death-by-attenuating-nf-%C3%AE%C2%BAb-mediated-regulation-of-trpc1-expression-and-autophagy
#13
Pramod Sukumaran, Yuyang Sun, Neil Antonson, Brij B Singh
Alterations in Ca(2+) homeostasis affect neuronal survival. However, the identity of Ca(2+) channels and the mechanisms underlying neurotoxin-induced neuronal degeneration are not well understood. In this study, the dopaminergic neurotoxins 6-hydroxydopamine (6-OHDA) and 1-methyl -4-phenylpyridium ions (MPP(+)/MPTP), which mimic Parkinson's disease (PD), induced neuronal degeneration by decreasing store-mediated Ca(2+) entry. The function of the transient receptor potential canonical (TRPC)-1 channel was decreased upon exposure to the neurotoxins, followed by a decrease in TRPC1 expression...
November 17, 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/29150461/gabaa-receptor-activation-in-the-allosteric-coagonist-model-framework-relationship-between-ec50-and-basal-activity
#14
Gustav Akk, Daniel J Shin, Allison L Germann, Joseph H Steinbach
The concerted transition model for multimeric proteins is a simple formulation for analyzing the behavior of transmitter-gated ion channels. Here, we use the model to examine the relationship between the EC50 for activation of the GABAA receptor by the transmitter GABA and basal activity employing concatemeric ternary GABAA receptors expressed in Xenopus oocytes. The basal activity reflects receptor function in the absence of transmitter, and can be changed either by mutation to increase constitutive activity, or by addition of a second agonist (acting at a different site) to increase background activity...
November 17, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/29149567/preparation-of-lithium-titanate-reduced-graphene-oxide-composites-with-3d-fishnet-like-conductive-structure-via-a-gas-foaming-method-for-high-rate-lithium-ion-batteries
#15
Tao Meng, Fenyun Yi, Honghong Cheng, Junnan Hao, Dong Shu, Shixu Zhao, Chun He, Xiaona Song, Fan Zhang
Using ammonium chloride (NH4Cl) as the pore-forming agent, three-dimensional (3D) "fishnet-like" lithium titanate/reduced graphene oxide (LTO/G) composites with hierarchical porous structure are prepared via a gas-foaming method. SEM and TEM images show that in the composite prepared with the NH4Cl concentration of 1 mg mL-1 (1-LTO/G), LTO particles with sizes of 50~100 nm disperse homogeneously on the 3D "fishnet-like" graphene sheets. The nitrogen-sorption analyses reveal the existence of micro/mesopores, which is attributed to the introduction of NH4Cl into the gap between the graphene sheets that further decomposes into gases and produces hierarchical pores during the thermal treatment process...
November 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29148067/should-theophylline-be-added-to-the-j-wave-syndrome-therapeutic-armamentarium
#16
EDITORIAL
Charles Antzelevitch, Sami Viskin
The substrate for both early repolarization syndrome (ERS) and Brugada syndrome (BrS), the so-called J wave syndromes, has been shown to develop as a consequence of genetic variants causing a loss of function of inward currents such sodium (INa ) and calcium (ICa ) channel currents or a gain of function in outward currents such as the transient outward current (Ito ). These changes in ion channel function result in an outward shift of the balance of currents active during the early phases of the epicardial action potential in the right ventricular outflow tract (RVOT) of the heart in the case BrS and in the inferior left ventricle in the case of ERS...
November 16, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/29147699/strain-relaxation-and-ambipolar-electrical-transport-in-gaas-insb-core-shell-nanowires
#17
Torsten Rieger, Patrick Zellekens, Natalia Demarina, Ali Al Hassan, Franz Josef Hackemüller, Hans Lüth, Ullrich Pietsch, Thomas Schäpers, Detlev Grützmacher, Mihail Ion Lepsa
The growth, crystal structure, strain relaxation and room temperature transport characteristics of GaAs/InSb core-shell nanowires grown using molecular beam epitaxy are investigated. Due to the large lattice mismatch between GaAs and InSb of 14%, a transition from island-based to layer-like growth occurs during the formation of the shell. High resolution transmission electron microscopy in combination with geometric phase analyses as well as X-ray diffraction with synchrotron radiation are used to investigate the strain relaxation and prove the existence of different dislocations relaxing the strain on zinc blende and wurtzite core-shell nanowire segments...
November 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/29146979/thickness-dependent-parasitic-channel-formation-at-aln-si-interfaces
#18
Hareesh Chandrasekar, K N Bhat, Muralidharan Rangarajan, Srinivasan Raghavan, Navakanta Bhat
The performance of GaN-on-Silicon electronic devices is severely degraded by the presence of a parasitic conduction pathway at the nitride-substrate interface which contributes to switching losses and lower breakdown voltages. The physical nature of such a parasitic channel and its properties are however, not well understood. We report on a pronounced thickness dependence of the parasitic channel formation at AlN/Si interfaces due to increased surface acceptor densities at the interface in silicon. The origin of these surface acceptors is analyzed using secondary ion mass spectroscopy measurements and traced to thermal acceptor formation due to Si-O-N complexes...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29145442/downregulation-of-kcnmb4-expression-and-changes-in-bk-channel-subtype-in-hippocampal-granule-neurons-following-seizure-activity
#19
Luke E Whitmire, Ling Ling, Vladslav Bugay, Chase M Carver, Santosh Timilsina, Hui-Hsiu Chuang, David B Jaffe, Mark S Shapiro, Jose E Cavazos, Robert Brenner
A major challenge is to understand maladaptive changes in ion channels that sets neurons on a course towards epilepsy development. Voltage- and calcium-activated K+ (BK) channels contribute to early spike timing in neurons, and studies indicate that the BK channel plays a pathological role in increasing excitability early after a seizure. Here, we have investigated changes in BK channels and their accessory β4 subunit (KCNMB4) in dentate gyrus (DG) granule neurons of the hippocampus, key neurons that regulate excitability of the hippocampus circuit...
2017: PloS One
https://www.readbyqxmd.com/read/29144441/g-protein-coupled-receptors-targeted-by-analgesic-venom-peptides
#20
REVIEW
James T Daniel, Richard J Clark
Chronic pain is a complex and debilitating condition associated with a large personal and socioeconomic burden. Current pharmacological approaches to treating chronic pain such as opioids, antidepressants and anticonvulsants exhibit limited efficacy in many patients and are associated with dose-limiting side effects that hinder their clinical use. Therefore, improved strategies for the pharmacological treatment of pathological pain are urgently needed. G-protein coupled receptors (GPCRs) are ubiquitously expressed on the surface of cells and act to transduce extracellular signals and regulate physiological processes...
November 16, 2017: Toxins
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