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https://www.readbyqxmd.com/read/28737931/semi-ordered-hierarchical-metallic-network-for-fast-and-large-charge-induced-strain
#1
Chuan Cheng, Lukas Lührs, Tobias Krekeler, Martin Ritter, Jörg Weissmüller
Nanoporous metallic actuators for artificial muscle applications are distinguished by combining the low operating voltage which is otherwise reserved for polymer-based actuators with interesting values of strain amplitude, strength and stiffness that are comparable of those of piezoceramics. We report a nanoporous metal actuator with enhanced strain amplitude and accelerated switching. Our 3D macroscopic metallic muscle has semi-ordered and hierarchical nanoporous structure, in which µm-sized tubes align perpendicular with the sample surface, while nm-sized ligaments consist of the tube walls...
July 24, 2017: Nano Letters
https://www.readbyqxmd.com/read/28737760/channel-opening-and-gating-mechanism-in-ampa-subtype-glutamate-receptors
#2
Edward C Twomey, Maria V Yelshanskaya, Robert A Grassucci, Joachim Frank, Alexander I Sobolevsky
AMPA-subtype ionotropic glutamate receptors mediate fast excitatory neurotransmission throughout the central nervous system. Gated by the neurotransmitter glutamate, AMPA receptors are critical for synaptic strength and dysregulation of AMPA receptor-mediated signalling is linked to numerous neurological diseases. Here, we use cryo-electron microscopy to solve the structures of AMPA receptor-auxiliary subunit complexes in the apo, antagonist and agonist-bound states and elucidate the iris-like mechanism of ion channel opening...
July 24, 2017: Nature
https://www.readbyqxmd.com/read/28736757/malaria-parasite-proteins-involved-in-nutrient-channels-at-the-host-erythrocyte-membrane-advances-and-questions-for-future-research
#3
S Chalapareddy, S A Desai
Erythrocytes infected malaria parasites have increased permeability to nutrients and other solutes, as mediated by an unusual ion channel known as the plasmodial surface anion channel (PSAC). Although the increased permeability of infected erythrocytes was identified more than 70 years ago and subsequently characterized with tracer studies, its mechanism and role in parasite biology remained unclear until the introduction of patch-clamp methods and high-throughput screening technologies. These methods discovered and implicated PSAC as the primary mechanism, determined that this channel is essential for parasite development, led to identification of the channel's genes, and stimulated antimalarial drug discovery against this target...
March 2017: Int J Curr Multidiscip Stud
https://www.readbyqxmd.com/read/28735770/to4-the-first-tityus-obscurus-%C3%AE-toxin-fully-electrophysiologically-characterized-on-human-sodium-channel-isoforms
#4
Harry Morales Duque, Caroline Barbosa Farias Mourão, Diogo Vieira Tibery, Eder Alves Barbosa, Leandro Ambrósio Campos, Elisabeth Ferroni Schwartz
Many scorpion toxins that act on sodium channels (NaScTxs) have been characterized till date. These toxins may act modulating the inactivation or the activation of sodium channels and are named α- or β-types, respectively. Some venom toxins from Tityus obscurus (Buthidae), a scorpion widely distributed in the Brazilian Amazon, have been partially characterized in previous studies; however, little information about their electrophysiological role on sodium ion channels has been published. In the present study, we describe the purification, identification and electrophysiological characterization of a NaScTx, which was first described as Tc54 and further fully sequenced and renamed To4...
July 20, 2017: Peptides
https://www.readbyqxmd.com/read/28735752/conformational-changes-of-cftr-upon-phosphorylation-and-atp-binding
#5
Zhe Zhang, Fangyu Liu, Jue Chen
The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel evolved from an ATP-binding cassette transporter. CFTR channel gating is strictly coupled to phosphorylation and ATP hydrolysis. Previously, we reported essentially identical structures of zebrafish and human CFTR in the dephosphorylated, ATP-free form. Here, we present the structure of zebrafish CFTR in the phosphorylated, ATP-bound conformation, determined by cryoelectron microscopy to 3.4 Å resolution. Comparison of the two conformations shows major structural rearrangements leading to channel opening...
July 18, 2017: Cell
https://www.readbyqxmd.com/read/28734362/discrimination-of-bacteria-by-rapid-sensing-their-metabolic-volatiles-using-an-aspiration-type-ion-mobility-spectrometer-a-ims-and-gas-chromatography-mass-spectrometry-gc-ms
#6
Ileana Andreea Ratiu, Victor Bocos-Bintintan, Adrian Patrut, Victor Hugo Moll, Matthew Turner, C L Paul Thomas
The objective of our study was to investigate whether one may quickly and reliably discriminate different microorganism strains by direct monitoring of the headspace atmosphere above their cultures. Headspace samples above a series of in vitro bacterial cultures were directly interrogated using an aspiration type ion mobility spectrometer (a-IMS), which produced distinct profiles ("fingerprints") of ion currents generated simultaneously by the detectors present inside the ion mobility cell. Data processing and analysis using principal component analysis showed net differences in the responses produced by volatiles emitted by various bacterial strains...
August 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28734079/post-translational-palmitoylation-controls-the-voltage-gating-and-lipid-raft-association-of-calhm1-channel
#7
Akiyuki Taruno, Hongxin Sun, Koichi Nakajo, Tatsuro Murakami, Yasuyoshi Ohsaki, Mizuho A Kido, Fumihito Ono, Yoshinori Marunaka
Emerging roles of CALHM1, a recently discovered voltage-gated ion channel, include purinergic neurotransmission of tastes in taste buds and memory formation in the brain, highlighting its physiological importance. However, the regulatory mechanisms of the CALHM1 channel remain entirely unexplored, hindering full understanding of its contribution in vivo. In fact, the different gating properties of CALHM1 in vivo and in vitro suggest undiscovered regulatory mechanisms. Here, in searching for post-translational regulatory mechanisms, we discovered the regulation of CALHM1 gating and association with lipid microdomains via protein S-palmitoylation, the only reversible lipid modification of proteins on cysteine residues...
July 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28733618/cellular-interfaces-with-hydrogen-bonded-organic-semiconductor-hierarchical-nanocrystals
#8
Mykhailo Sytnyk, Marie Jakešová, Monika Litviňuková, Oleksandr Mashkov, Dominik Kriegner, Julian Stangl, Jana Nebesářová, Frank W Fecher, Wolfgang Schöfberger, Niyazi Serdar Sariciftci, Rainer Schindl, Wolfgang Heiss, Eric Daniel Głowacki
Successful formation of electronic interfaces between living cells and semiconductors hinges on being able to obtain an extremely close and high surface-area contact, which preserves both cell viability and semiconductor performance. To accomplish this, we introduce organic semiconductor assemblies consisting of a hierarchical arrangement of nanocrystals. These are synthesised via a colloidal chemical route that transforms the nontoxic commercial pigment quinacridone into various biomimetic three-dimensional arrangements of nanocrystals...
July 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28733226/allatoregulatory-like-systems-and-changes-in-cytosolic-ca-2-modulate-feeding-behaviour-in-hydra
#9
María Eugenia Alzugaray, Jorge Rafael Ronderos
Allatotropin (AT) and allatostatin-C (AST-C) are neuropeptides originally characterized by their ability to modulate the secretion of juvenile hormones in insects. Beyond the allatoregulatory function, these neuropeptides are pleiotropic acting as myoregulators not only in insects, but also in other groups of invertebrates. We have previously proposed the existence of AT and AST-C like systems in Hydra sp., a member of the phylum Cnidaria, which is a basal group of Metazoa, sharing a common ancestor with Bilateria...
July 18, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28732812/extracts-and-compounds-active-on-trp-ion-channels-from-waldheimia-glabra-a-ritual-medicinal-plant-from-himalaya
#10
Annamaria Giorgi, Angela Bassoli, Gigliola Borgonovo, Sara Panseri, Alessandra Manzo, Daniela Pentimalli, Aniello Schiano Moriello, Luciano De Petrocellis
BACKGROUND: Waldheimia glabra (Decne.) Regel is a wild plant from the Himalayan Mountains, commonly known as Smooth Ground Daisy. This plant is traditionally used by local populations in religious rituals (incense) or in traditional herbal medicine to treat skin diseases, headache, joint pain and fever. In literature few data are available on the investigation of this aromatic plant. PURPOSE: The present work aims at deepening knowledge about the chemical composition of W...
August 15, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/28732502/chronic-glucocorticoid-exposure-activates-bk-nlrp1-signal-involving-in-hippocampal-neuron-damage
#11
Biqiong Zhang, Yaodong Zhang, Wenning Wu, Tanzhen Xu, Yanyan Yin, Junyan Zhang, Dake Huang, Weizu Li
BACKGROUND: Neuroinflammation mediated by NLRP1 (nucleotide-binding oligomerization domain (NOD)-like receptor protein 1) inflammasome plays an important role in many neurological diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD). Our previous studies showed that chronic glucocorticoid (GC) exposure increased brain inflammation via NLRP1 inflammasome and induce neurodegeneration. However, little is known about the mechanism of chronic GC exposure on NLRP1 inflammasome activation in hippocampal neurons...
July 21, 2017: Journal of Neuroinflammation
https://www.readbyqxmd.com/read/28732465/genome-wide-signals-of-positive-selection-in-strongylocentrotid-sea-urchins
#12
Kord M Kober, Grant H Pogson
BACKGROUND: Comparative genomics studies investigating the signals of positive selection among groups of closely related species are still rare and limited in taxonomic breadth. Such studies show great promise in advancing our knowledge about the proportion and the identity of genes experiencing diversifying selection. However, methodological challenges have led to high levels of false positives in past studies. Here, we use the well-annotated genome of the purple sea urchin, Strongylocentrotus purpuratus, as a reference to investigate the signals of positive selection at 6520 single-copy orthologs from nine sea urchin species belonging to the family Strongylocentrotidae paying careful attention to minimizing false positives...
July 21, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28732201/small-molecules-for-early-endosome-specific-patch-clamping
#13
Cheng-Chang Chen, Elisabeth S Butz, Yu-Kai Chao, Yulia Grishchuk, Lars Becker, Stefan Heller, Susan A Slaugenhaupt, Martin Biel, Christian Wahl-Schott, Christian Grimm
To resolve the subcellular distribution of endolysosomal ion channels, we have established a novel experimental approach to selectively patch clamp Rab5 positive early endosomes (EE) versus Rab7/LAMP1-positive late endosomes/lysosomes (LE/LY). To functionally characterize ion channels in endolysosomal membranes with the patch-clamp technique, it is important to develop techniques to selectively enlarge the respective organelles. We found here that two small molecules, wortmannin and latrunculin B, enlarge Rab5-positive EE when combined but not Rab7-, LAMP1-, or Rab11 (RE)-positive vesicles...
July 20, 2017: Cell Chemical Biology
https://www.readbyqxmd.com/read/28731719/discovery-structure-activity-relationship-and-binding-mode-of-imidazo-1-2-a-pyridine-series-of-autotaxin-inhibitors
#14
Agnès Joncour, Nicolas Desroy, Christopher Housseman, Xavier Bock, Natacha Bienvenu, Laëtitia Cherel, Virginie Labeguere, Christophe Peixoto, Denis Annoot, Luce Lepissier, Jörg Heiermann, Willem Jan Hengeveld, Gregor Pilzak, Alain Monjardet, Emanuelle Wakselman, Veronique Roncoroni, Sandrine Le Tallec, René Galien, Christelle David, Nele Vandervoort, Thierry Christophe, Katja Conrath, Mia Jans, Alexandre Wohlkonig, Robert Touitou, Damien Fleury, Lionel Vercheval, Patrick Mollat, Nicolas Triballeau, Ellen Van der Aar, Reginald Brys, Bertrand Heckmann
Autotaxin (ATX) is a secreted enzyme playing a major role in the production of lysophosphatidic acid (LPA) in blood through hydrolysis of lysophosphatidyl choline (LPC). The ATX-LPA signaling axis arouses a high interest in the drug discovery industry as it has been implicated in several diseases including cancer, fibrotic diseases and inflammation among others. An imidazo[1,2-a]pyridine series of ATX inhibitors was identified out of a high throughput screening (HTS). A co-crystal structure with one of these compounds and ATX revealed a novel binding mode with occupancy of the hydrophobic pocket and channel of ATX but no interaction with zinc ions of the catalytic site...
July 21, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28731314/desensitization-to-chemical-and-food-sensitivities-by-low-dose-immunotherapy-ascertained-by-provocation-neutralization-is-associated-with-reduced-influx-of-calcium-ions-into-lymphocytes
#15
Basant K Puri, John McLaren Howard, Jean A Monro
Background Food and chemical sensitivities have detrimental effects on health and the quality of life. The natural course of such sensitivities can potentially be altered through various types of allergen-specific immunotherapy, including low-dose immunotherapy. The molecular mechanism by which low-dose immunotherapy causes desensitization has not thus far been elucidated. While resting lymphocytes maintain a low cytosolic calcium ion concentration, antigen receptor signaling results in calcium ion influx, predominantly via store-operated calcium channels...
April 26, 2017: Journal of Complementary & Integrative Medicine
https://www.readbyqxmd.com/read/28730837/molecular-basis-of-trpa1-regulation-in-nociceptive-neurons-a-review
#16
A Kádková, V Synytsya, J Krusek, L Zímová, V Vlachová
Transient receptor potential A1 (TRPA1) is an excitatory ion channel that functions as a cellular sensor, detecting a wide range of proalgesic agents such as environmental irritants and endogenous products of inflammation and oxidative stress. Topical application of TRPA1 agonists produces an acute nociceptive response through peripheral release of neuropeptides, purines and other transmitters from activated sensory nerve endings. This, in turn, further regulates TRPA1 activity downstream of G-protein and phospholipase C-coupled signaling cascades...
July 18, 2017: Physiological Research
https://www.readbyqxmd.com/read/28730802/sensing-single-molecule-penetration-into-nanopores-pushing-the-time-resolution-to-the-diffusion-limit
#17
Igor Bodrenko, Jiajun Wang, Samuele Salis, Mathias Winterhalter, Matteo Ceccarelli
To quantify small molecule penetration into and eventually permeation through nanopores, we applied an improved excess-noise analysis of the ion current fluctuation caused by entering molecules. The kinetic parameters of substrate entry and leave are derived from a two-state Markov model, analyzing the substrate concentration depen- dence of the average ion current and its variance. Including filter corrections allows one to detect the transition rates beyond the cutoff frequency, fc, of the instrumental ion-current filter...
July 21, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28730575/the-effect-of-chronic-fluorosis-on-calcium-ions-and-camkii%C3%AE-and-c-fos-expression-in-the-rat-hippocampus
#18
Yao Teng, Jing Zhang, Zigui Zhang, Juan Feng
This study investigated neurotoxicity of chronic fluorosis in the rat hippocampus. Newly weaning, male, Sprague-Dawley (SD) rats were administered 15, 30, and 60 mg/L sodium fluoride (NaF) solution (fluorine ion concentration 8.25, 16.50, and 33.00 mg/L, respectively), and tap water, for 18 months. The neurotoxicological mechanism was examined with a focus on intracellular calcium overload. Results showed that as the fluoride concentration increased, calcium ion concentration [Ca(2+)], the expression of calcium/calmodulin-dependent protein kinase II α (CaMKIIα), and the expression of catus proto-oncogene protein c-fos (c-fos) all tend to increase...
July 20, 2017: Biological Trace Element Research
https://www.readbyqxmd.com/read/28729840/cardiac-subtype-specific-modeling-of-kv1-5-ion-channel-deficiency-using-human-pluripotent-stem-cells
#19
Maike Marczenke, Ilaria Piccini, Isabella Mengarelli, Jakob Fell, Albrecht Röpke, Guiscard Seebohm, Arie O Verkerk, Boris Greber
The ultrarapid delayed rectifier K(+) current (IKur), mediated by Kv1.5 channels, constitutes a key component of the atrial action potential. Functional mutations in the underlying KCNA5 gene have been shown to cause hereditary forms of atrial fibrillation (AF). Here, we combine targeted genetic engineering with cardiac subtype-specific differentiation of human induced pluripotent stem cells (hiPSCs) to explore the role of Kv1.5 in atrial hiPSC-cardiomyocytes. CRISPR/Cas9-mediated mutagenesis of integration-free hiPSCs was employed to generate a functional KCNA5 knockout...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28729686/ultralow-voltage-operation-of-biologically-assembled-all-carbon-nanotube-nanomesh-transistors-with-ion-gel-gate-dielectrics
#20
Hye-Hyeon Byeon, Kein Kim, Woong Kim, Hyunjung Yi
The demonstration of field-effect transistors (FETs) based entirely on single-walled carbon nanotubes (SWNTs) would enable the fabrication of high-on-current, flexible, transparent and stretchable devices owing to the excellent electrical, optical, and mechanical properties of SWNTs. Fabricating all-SWNT-based FETs via simple solution process, at room temperature and without using lithography and vacuum process could further broaden the applicability of all-SWNT-FETs. In this work, we report on biologically assembled all SWNT-based transistors and demonstrate that ion-gel-gated network structures of unsorted SWNTs assembled using a biological template material enabled operation of SWNT-based transistors at a very low voltage...
July 20, 2017: Scientific Reports
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