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Proton transport

Manami Akasaka, Atsushi Kamei, Nami Araya, Kotaro Oyama, Makoto Sasaki
No abstract text is available yet for this article.
October 15, 2018: Pediatrics International: Official Journal of the Japan Pediatric Society
Till Überrück, Oliver Neudert, Klaus-Dieter Kreuer, Bernhard Blümich, Josef Granwehr, Siegfried Stapf, Songi Han
Nafion is the most common material used as a proton exchange membrane in fuel cells. Yet, details of the transport pathways for protons and water in the inner membrane are still under debate. Overhauser Dynamic Nuclear Polarization (ODNP) has proven to be a useful tool for probing hydration dynamics and interactions within 5-8 Å of protein and soft material surfaces. Recently it was suggested that ODNP can also be applied to analyze surface water dynamics along Nafion's inner membrane. Here we interrogate the viability of this method for Nafion by carrying out a series of measurements relying on 1H nuclear magnetic resonance (NMR) relaxometry and diffusometry experiments with and without ODNP hyperpolarization, accompanied by other complementary characterization methods including small angle X-ray scattering (SAXS), thermal gravimetric analysis (TGA) of hydration, and proton conductivity by AC impedance spectroscopy...
October 15, 2018: Physical Chemistry Chemical Physics: PCCP
Cristina Benito-Muñoz, Almudena Perona, David Abia, Helena G Dos Santos, Enrique Núñez, Carmen Aragón, Beatriz López-Corcuera
Neurotransmitter removal from glycine-mediated synapses relies on two sodium-driven high-affinity plasma membrane GlyTs that control neurotransmitter availability. Mostly glial GlyT1 is the main regulator of glycine synaptic levels, whereas neuronal GlyT2 promotes the recycling of synaptic glycine and supplies neurotransmitter for presynaptic vesicle refilling. The GlyTs differ in sodium:glycine symport stoichiometry, showing GlyT1 a 2:1 and GlyT2 a 3:1 sodium:glycine coupling. Sodium binds to the GlyTs at two conserved Na+ sites: Na1 and Na2...
2018: Frontiers in Molecular Neuroscience
Panagiotis D Velentzas, Lejie Zhang, Gautam Das, Tsun-Kai Chang, Charles Nelson, William R Kobertz, Eric H Baehrecke
Nutrient availability influences the production and degradation of materials that are required for cell growth and survival. Autophagy is a nutrient-regulated process that is used to degrade cytoplasmic materials and has been associated with human diseases. Solute transporters influence nutrient availability and sensing, yet we know little about how transporters influence autophagy. Here, we screen for solute transporters that are required for autophagy-dependent cell death and identify CG11665/hermes. We show that hermes is required for both autophagy during steroid-triggered salivary gland cell death and TNF-induced non-apoptotic eye cell death...
October 9, 2018: Developmental Cell
Vishwanatha K Rao, Gerardo Zavala, Abhijit Deb Roy, Richard E Mains, Betty A Eipper
The biosynthetic and endocytic pathways of secretory cells are characterized by progressive luminal acidification, a process which is crucial for posttranslational modifications and membrane trafficking. This progressive fall in luminal pH is mainly achieved by the vacuolar-type-H+ ATPase (V-ATPase). V-ATPases are large, evolutionarily ancient rotary proton pumps that consist of a peripheral V1 complex, which hydrolyzes ATP, and an integral membrane V0 complex, which transports protons from the cytosol into the lumen...
October 14, 2018: Journal of Cellular Physiology
Haiyan Hu, Jie He, Junjie Zhao, Xingqi Ou, Hongmin Li, Zhengang Ru
Soil acidification is one of major problems limiting crop growth and especially becoming increasingly serious in China owing to excessive use of nitrogen fertilizer. Only the STOP1 of Arabidopsis was identified clearly sensitive to proton rhizotoxicity and the molecular mechanism for proton toxicity tolerance of plants is still poorly understood. The main objective of this study was to investigate the transcriptomic change in plants under the low pH stress. The low pH as a single factor was employed to induce the response of the wheat seedling roots...
November 2018: Genes & Genomics
Xiaowei Yang, Yinhuan Zhang, Yan Liu, Chang Chen, Wenjuan Xu, Hongbin Xiao
Emodin is a natural anthraquinone derivative that occurs in many Chinese medicinal herbs. It might induce liver damage, but the mechanism is not clear. In this research, seven groups of Sprague-Dawley (SD) rats with three doses of emodin were used. The liver injury was examined by analyzing biochemical indexes and histopathology. Altered proteins between the control group (CG) and the liver injury group were determined by proteomic technology. The results showed that emodin causes liver injury in a time- and dose-dependent manner...
September 1, 2018: Toxicology Research
Gal Masrati, Manish Dwivedi, Abraham Rimon, Yael Gluck-Margolin, Amit Kessel, Haim Ashkenazy, Itay Mayrose, Etana Padan, Nir Ben-Tal
Cation/proton antiporters (CPAs) play a major role in maintaining living cells' homeostasis. CPAs are commonly divided into two main groups, CPA1 and CPA2, and are further characterized by two main phenotypes: ion selectivity and electrogenicity. However, tracing the evolutionary relationships of these transporters is challenging because of the high diversity within CPAs. Here, we conduct comprehensive evolutionary analysis of 6537 representative CPAs, describing the full complexity of their phylogeny, and revealing a sequence motif that appears to determine central phenotypic characteristics...
October 11, 2018: Nature Communications
Andreas Nazet, Richard Buchner
Dielectric relaxation spectra of three members of the alkylammonium formate family of protic ionic liquids (PILs), namely, ethylammonium formate (EAF), n -butylammonium formate (BuAF), and n -pentylammonium formate (PeAF), as well as the pseudo-PIL triethylamine + formic acid (molar ratio 1:2; TEAF) have been studied over a wide frequency (50 MHz to 89 GHz) and temperature range (5-65 °C), complemented by measurements of their density, viscosity, and conductivity. It turned out that the dominating relaxation of EAF, BuAF, and PeAF arises from both cation and anion reorientations which are synchronized in their dynamics due to hydrogen bonding...
May 21, 2018: Journal of Chemical Physics
Ary Nasi, Natália Sousa Freitas Queiroz, Nelson H Michelsohn
BACKGROUND: Prolonged monitoring increased our knowledge on gastroesophageal reflux (GER), and the disease became known as gastroesophageal reflux disease (GERD). Prolonged reflux monitoring permits the diagnosis of GERD when endoscopic findings are not enough to characterize it. OBJECTIVE: The objective of this paper is to review the current knowledge on impedance-pH monitoring, taking into account the published literature and the authors experience with 1,200 exams...
October 4, 2018: Arquivos de Gastroenterologia
Dingyuan I Sun, Alexia Tasca, Maximilian Haas, Grober Baltazar, Richard M Harland, Walter E Finkbeiner, Peter Walentek
Na+/H+ exchangers (NHEs) represent a highly conserved family of ion transporters that regulate pH homeostasis. NHEs as well as other proton transporters were previously linked to the regulation of the Wnt signaling pathway, cell polarity signaling, and mucociliary function. Furthermore, mutations in the gene SLC9A3 (encoding NHE3) were detected as additional risk factors for airway infections in cystic fibrosis patients. Here, we used the Xenopus embryonic mucociliary epidermis as well as human airway epithelial cells (HAECs) as models to investigate the functional roles of NHEs in mucociliary development and regeneration...
October 9, 2018: Cells, Tissues, Organs
Hong-Hsiang Guan, Yin-Cheng Hsieh, Pei-Ju Lin, Yen-Chieh Huang, Masato Yoshimura, Li-Ying Chen, Shao-Kang Chen, Phimonphan Chuankhayan, Chien-Chih Lin, Nai-Chi Chen, Atsushi Nakagawa, Sunney I Chan, Chun-Jung Chen
The membrane-embedded quinol:fumarate reductase (QFR) in anaerobic bacteria catalyzes the reduction of fumarate to succinate by quinol in the anaerobic respiratory chain. The electron/proton-transfer pathways in QFRs remain controversial. Here we report the crystal structure of QFR from the anaerobic sulphate-reducing bacterium Desulfovibrio gigas (D. gigas) at 3.6 Å resolution. The structure of the D. gigas QFR is a homo-dimer, each protomer comprising two hydrophilic subunits, A and B, and one transmembrane subunit C, together with six redox cofactors including two b-hemes...
October 8, 2018: Scientific Reports
Vito Porcelli, Angelo Vozza, Valeria Calcagnile, Ruggiero Gorgoglione, Roberto Arrigoni, Flavia Fontanesi, Carlo M T Marobbio, Alessandra Castegna, Ferdinando Palmieri, Luigi Palmieri
The genome of Saccharomyces cerevisiae encodes 35 members of the mitochondrial carrier family (MCF) and 58 MCF members are coded by the genome of Arabidopsis thaliana, most of which have been functionally characterized. Here two members of this family, Ymc2p from S. cerevisiae and BOU from Arabidopsis, have been thoroughly characterized. These proteins were overproduced in bacteria and reconstituted into liposomes. Their transport properties and kinetic parameters demonstrate that Ymc2p and BOU transport glutamate, and to a much lesser extent L-homocysteinesulfinate, but not other amino acids and many other tested metabolites...
November 2018: Biochimica et biophysica acta. Bioenergetics
Simon Fuchs, Sierra C Hansen, Marie Markones, Evgeny V Mymrikov, Heiko Heerklotz, Carola Hunte
The Na+ /H+ exchanger NHE1 is critical for cell vitality as it controls intracellular pH and cell volume. Its functionality is influenced by calcineurin B homologous proteins (CHPs). The human isoform CHP3 is important for transport of NHE1 to the plasma membrane and for its activity. Here, we characterized the binding interaction of human CHP3 with the regulatory domain of NHE1. The exact binding site of CHP3 was previously debated. CHP3 as well as both regions of NHE1 in question were produced and purified...
October 4, 2018: Scientific Reports
Nathan E Thomas, Chao Wu, Emma A Morrison, Anne E Robinson, Josephine P Werner, Katherine Henzler-Wildman
Ion-coupled transporters must regulate access of ions and substrates into and out of the binding site to actively transport substrates and minimize dissipative leak of ions. Within the single-site alternating access model, competitive substrate binding forms the foundation of ion-coupled antiport. Strict competition between substrates leads to stoichiometric antiport without slippage. However, recent NMR studies of the bacterial multidrug transporter EmrE have demonstrated that this multidrug transporter can simultaneously bind drug and proton, which will affect the transport stoichiometry and efficiency of coupled antiport...
October 4, 2018: Journal of Biological Chemistry
Xi Chen, Huanan Zhang, Ramya H Tunuguntla, Aleksandr Noy
Limited biocompatibility and fouling propensity can restrict real-world applications of a large variety of biosensors. Biological systems are adept at protecting and separating vital components of biological machinery with semipermeable membranes that often contain defined pores and gates to restrict transmembrane transport only to specific species. Here we use a similar approach for creating fouling-resistant pH sensors. We integrate silicon nanoribbon transistor sensors with an antifouling lipid bilayer coating that contains proton-permeable carbon nanotube porin (CNTP) channels and demonstrate robust pH detection in a variety of complex biological fluids...
October 4, 2018: Nano Letters
Tao Zhang, Zhongquan Liao, Leonardo Medrano Sandonas, Arezoo Dianat, Xiaoling Liu, Peng Xiao, Ihsan Amin, Rafael Gutierrez, Tao Chen, Ehrenfried Zschech, Gianaurelio Cuniberti, Rainer Jordan
Mass transport through graphene is receiving increasing attention due to the potential for molecular sieving. Experimental studies are mostly limited to the translocation of protons, ions, and water molecules, and results for larger molecules through graphene are rare. Here, we perform controlled radical polymerization with surface-anchored self-assembled initiator monolayer in a monomer solution with single-layer graphene separating the initiator from the monomer. We demonstrate that neutral monomers are able to pass through the graphene (via native defects) and increase the graphene defects ratio (Raman ID /IG ) from ca...
October 3, 2018: Nature Communications
Yejin Jang, Jin Soo Shin, Yi-Seul Yoon, Yun Young Go, Hye Won Lee, Oh Seung Kwon, Sehee Park, Man-Seong Park, Meehyein Kim
Screening of chemical libraries with 2,000 synthetic compounds identified salinomycin as a hit against influenza A and B viruses with 50% effective concentrations ranging from 0.4 to 4.3 μM in cells. This compound is a carboxylic polyether ionophore that exchanges monovalent ions for protons across lipid bilayer membranes. Monitoring the time course of viral infection showed that salinomycin blocked nuclear migration of viral nuclear protein (NP) that is the most abundant component of the viral ribonucleoprotein (vRNP) complex...
October 3, 2018: Journal of Virology
Angelique Jarry, Sandrine Ricote, Aaron Geller, Christopher Pellegrinelli, Xiaohang Zhang, David M Stewart, Ichiro Takeuchi, Eric D Wachsman, Ethan J Crumlin, Bryan W Eichhorn
Performance of Proton-Solid Oxide Fuel Cells (H+-SOFC) is governed by ion transport through solid/gas interfaces. Major breakthroughs are then intrinsically linked to a detailed understanding of how parameters tailoring bulk proton conductivity affect surface chemistry in situ, at an early stage. In this work, we studied proton and oxygen transport at the interface between H+-SOFC electrolyte BaCexZr0.9-xY0.1O2.95 (x = 0; 0.2; 0.9) thin films and the gas (100 mtorr of H2O and O2) by using synchrotron-based ambient pressure X-ray photoelectron spectroscopy (APXPS) at operating temperature (>400°C)...
October 3, 2018: ACS Applied Materials & Interfaces
D Jahn, M Träger, M Kis, C Brabetz, D Schumacher, A Blažević, M Ciobanu, M Pomorski, U Bonnes, S Busold, F Kroll, F-E Brack, U Schramm, M Roth
This article reports on the development of thin diamond detectors and their characterization for their application in temporal profile measurements of subnanosecond ion bunches. Two types of diamonds were used: a 20 μ m thin polycrystalline chemical vapor deposited (CVD) diamond and a membrane with a thickness of (5 ± 1) μ m etched out of a single crystal (sc) CVD diamond. The combination of a small detector electrode and an impedance matched signal outlet leads to excellent time response properties with a signal pulse resolution (FWHM) of τ = (113 ± 11) ps...
September 2018: Review of Scientific Instruments
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