Read by QxMD icon Read

Ion channel

Monica Bregante, Armando Carpaneto, Veronica Piazza, Francesca Sbrana, Massimo Vassalli, Marco Faimali, Franco Gambale
We investigated the biophysical properties of the transport mediated by ion channels in hemocytes from the hemolymph of the bivalve Mytilus galloprovincialis. Besides other transporters, mytilus hemocytes possess a specialized channel sensitive to the osmotic pressure with functional properties similar to those of other transport proteins present in vertebrates. As chloride fluxes may play an important role in the regulation of cell volume in case of modifications of the ionic composition of the external medium, we focused our attention on an inwardly-rectifying voltage-dependent, chloride-selective channel activated by negative membrane potentials and potentiated by the low osmolality of the external solution...
2016: PloS One
Tamara Hoffmann, Erhard Bremer
The development of a semi-permeable cytoplasmic membrane was a key event in the evolution of microbial proto-cells. As a result, changes in the external osmolarity will inevitably trigger water fluxes along the osmotic gradient. The ensuing osmotic stress has consequences for the magnitude of turgor and will negatively impact cell growth and integrity. No microorganism can actively pump water across the cytoplasmic membrane; hence, microorganisms have to actively adjust the osmotic potential of their cytoplasm to scale and direct water fluxes in order to prevent dehydration or rupture...
December 9, 2016: Biological Chemistry
Ruochen Fang, Huacheng Zhang, Liulin Yang, Huanting Wang, Ye Tian, Xi Zhang, Lei Jiang
Artificial nanochannels, inheriting smart gating functions of biological ion channels, promote the development of artificial functional nanofluidic devices for high-performance biosensing and electricity generation. However, gating states of the artificial nanochannels have been mainly realized through chemical modification of the channels with responsive molecules, and their gating states cannot be further regulated once the nanochannel is modified. In this work, we employed a new supramolecular layer-by-layer (LbL) self-assembly method to achieve reversible and adjustable multiple gating features in nanofluidic diodes...
December 9, 2016: Journal of the American Chemical Society
Michael A Cooper, Janelle M Ryals, Pau Yen Wu, Kellen D Wright, Katherine R Walter, Douglas E Wright
Dietary-associated diseases have increased tremendously in our current population, yet key molecular changes associated with high-fat diets that cause clinical prediabetes, obesity, hyperglycemia, and peripheral neuropathy remain unclear. This study examines molecular and metabolic aspects altered by voluntary exercise and a high-fat diet in the mouse dorsal root ganglion. Mice were examined for changes in mRNA and proteins encoding anti-inflammatory mediators, metabolic-associated molecules, and pain associated ion channels...
December 9, 2016: Journal of the Peripheral Nervous System: JPNS
Dhiman Das, Dinh Tuan Phan, Zhao Yugang, Kang Yuejun, Vincent Chan, Chun Yang
A novel continuous flow microfluidic platform specifically designed for environmental monitoring of O/W emulsions during an aftermath of oil spills is reported herein. Ionized polycyclic aromatic hydrocarbons which are toxic are readily released from crude oil to the surrounding water phase through the smaller oil droplets with enhanced surface area. Hence, a multi-module microfluidic device is fabricated to (1) form ion enrichment zones in the water phase of O/W emulsions for the ease of detection and (2) to separate micron-sized oil droplets from the O/W emulsions...
December 9, 2016: Electrophoresis
Yu-Bin Zheng, Shuang Zhao, Shuo-Hui Cao, Sheng-Lin Cai, Xiu-Hong Cai, Yao-Qun Li
In this article, we have demonstrated for the first time a triple stimuli-responsive nanofluidic diode that can rectify ionic current under multiple external stimuli including temperature, pH, and sugar. This diode was fabricated by immobilizing poly[2-(dimethylamino)ethyl methacrylate]-co-[4-vinyl phenylboronic acid] (P(DMAEMA-co-VPBA)) onto the wall of a single glass conical nanopore channel via surface-initiator atom transfer radical polymerization (SI-ATRP). The copolymer brushes contain functional groups sensitive to pH, temperature and sugar that can induce charge and configuration change to affect the status of the pore wall...
December 9, 2016: Nanoscale
Nana Song, Ruijuan Guan, Qian Jiang, Comron J Hassanzadeh, Yuyang Chu, Xiaomei Zhao, Xia Wang, Dawei Yang, Qijun Du, Xiang-Ping Chu, Linlin Shen
The role of acid-sensing ion channels (ASICs) in the ventrolateral medulla (VLM) remains uncertain. Here, we found that ASIC1a and ASIC2 are widely expressed in rat medulla, and the expression level is higher at neonatal stage as compared to adult stage. The two ASIC subunits co-localized in medualla neurons. Furthermore, pH reduction triggered typical ASIC-type currents in the medulla, including the VLM. These currents showed a pH50 value of 6.6 and were blocked by amiloride. Based on their sensitivity to psalmotoxin 1 (PcTx1) and zinc, homomeric ASIC1a and heteromeric ASIC1a/2 channels were likely responsible for acid-mediated currents in the mouse medulla...
December 9, 2016: Scientific Reports
Yeonho Song, Ji Hye Lee, Hoon Hwang, George C Schatz, Hyonseok Hwang
Potential of mean force (PMF) profiles and position-dependent diffusion coefficients of Na(+) and K(+) are calculated to elucidate the translocation of ions through a cyclic peptide nanotube, composed of 8 × cyclo[-(d-Leu-Trp)4-] rings, in water and in hydrated DMPC bilayers. The PMF profiles and PMF decomposition analysis for the monovalent cations show that favorable interactions of the cations with the CPN as well as the lipid bilayer and dehydration free energy penalties are two major competing factors which determine the free energy surface for ion transport through CPNs both in water and in lipid bilayers, and that the selectivity of CPNs to cations mainly arises from favorable interaction energies of cations with CPNs and lipid bilayers that are more dominant than the dehydration penalties...
November 23, 2016: Journal of Physical Chemistry. B
Andras Bodi, Katrin Lilja Sigurdardottir, Ágúst Kvaran, Ragnar Bjornsson, Ingvar Arnason
The threshold photoelectron spectra and threshold photoionization mass spectra of 1-halogenated-1-silacyclohexanes, for the halogens X = F, Cl, Br, and I, have been obtained using synchrotron vacuum ultraviolet radiation and photoelectron photoion coincidence spectroscopy. As confirmed by a similar ionization onset and density functional theory molecular orbitals, the ionization to the ground state is dominated by electron removal from the silacyclohexane ring for X = F, Cl, and Br, and from the halogen lone pair for X = I...
November 23, 2016: Journal of Physical Chemistry. A
Xingyu Lin, Qian Yang, Fei Yan, Bowen Zhang, Bin Su
In biology, all protein channels share a common feature of containing narrow pore regions with hydrophobic functional groups and selectivity filter regions abundant with charged residues, which work together to account for fast and selective mass transport in and out of cells. In this work, an ultrathin layer of polydimethylsiloxane (PDMS) was evaporated on the top orifices of charged silica nanochannels (2-3 nm in diameter and 60 nm in length) vertically attached to the electrode surface, and the resulting structure is designated as heterogeneous silica nanochannels (HSNs)...
December 7, 2016: ACS Applied Materials & Interfaces
Adam S Chatterley, Florian Lackner, C D Pemmaraju, Daniel M Neumark, Stephen R Leone, Oliver Gessner
The dissociation dynamics of ferrocene are explored following strong field ionization using femtosecond time-resolved extreme ultraviolet (XUV) transient absorption spectroscopy. Employing transitions in the vicinity of the iron 3p (M2,3) edge, the dissociation is monitored from the point of view of the iron atom. With low strong field pump intensities (≈2 × 10(13) W cm(-2)), only ferrocenium cations are produced, and their iron 3p absorption spectrum is reported. It very closely resembles the 3p spectrum of atomic Fe(+) ions but is red-shifted by 0...
December 8, 2016: Journal of Physical Chemistry. A
Yanyan Liang, Zhengping Liu
Ionic current rectification of nanofluidic diode membranes has been studied widely in recent years because it is analogous to the functionality of biological ion channels in principle. We report a new method to fabricate ionic current rectification membranes based on mesoporous silica confined in anodic aluminum oxide (AAO) membranes. Two types of mesostructured silica nanocomposites, hexagonal structure and nanoparticle stacked structure, were used to asymmetrically fill nanochannels of AAO membranes by a vapor-phase synthesis (VPS) method with aspiration approach and were further modified via sequence vapor infiltration (SVI) treatment...
December 9, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Tanmoy Saha, Amitosh Gautam, Arnab Mukherjee, Mayurika Lahiri, Pinaki Talukdar
Despite the great interest in artificial ion channel design, only a small number of channel-forming molecules are currently available for addressing challenging problems, particularly in the biological systems. Recent advances in chloride-mediated cell death, aided by synthetic ion carriers, encouraged us to develop chloride selective supramolecular ion channels. The present work describes vicinal diols, tethered to a rigid 1,3-diethynylbenzene core, as pivotal moieties for the barrel-rosette ion channel formation, and the activity of such channels was tuned by controlling the lipophilicity of designed monomers...
December 9, 2016: Journal of the American Chemical Society
Nicholas J Porter, Nicolas H Christianson, Christophe Decroos, David W Christianson
Histone deacetylase 8 (HDAC8) catalyzes the hydrolysis of acetyl-l-lysine to yield products l-lysine and acetate through a mechanism in which a nucleophilic water molecule is activated by a histidine general base and a catalytic metal ion (Zn(2+) or Fe(2+)). Acetyl-l-lysine also requires activation by metal coordination and a hydrogen bond with catalytic tyrosine Y306, which also functions in transition state stabilization. Interestingly, Y306 is located in the conserved glycine-rich loop G(302)GGGY. The potential flexibility afforded by the tetraglycine segment may facilitate induced-fit conformational changes in Y306 between "in" and "out" positions, as observed in related deacetylases...
December 6, 2016: Biochemistry
Cristina Moreno, Alicia de la Cruz, Carmen Valenzuela
Voltage gated potassium channels (KV) are membrane proteins that allow selective flow of K(+) ions in a voltage-dependent manner. These channels play an important role in several excitable cells as neurons, cardiomyocytes, and vascular smooth muscle. Over the last 20 years, it has been shown that omega-3 polyunsaturated fatty acids (PUFAs) enhance or decrease the activity of several cardiac KV channels. PUFAs-dependent modulation of potassium ion channels has been reported to be cardioprotective. However, the precise cellular mechanism underlying the cardiovascular benefits remained unclear in part because new PUFAs targets and signaling pathways continue being discovered...
2016: Frontiers in Physiology
Shaweta Gupta, Srirupa Chakraborty, Ridhima Vij, Anthony Auerbach
Nicotinic acetylcholine receptors are allosteric proteins that generate membrane currents by isomerizing ("gating") between resting and active conformations under the influence of neurotransmitters. Here, to explore the mechanisms that link the transmitter-binding sites (TBSs) with the distant gate, we use mutant cycle analyses to measure coupling between residue pairs, phi value analyses to sequence domain rearrangements, and current simulations to reproduce a microsecond shut component ("flip") apparent in single-channel recordings...
December 8, 2016: Journal of General Physiology
Shelley Fong, John A Chiorini, James Sneyd, Vinod Suresh
Previous studies have shown that localized delivery of the aquaporin-1 (AQP1) gene to the parotid duct can restore saliva flow in minipigs following irradiation-induced salivary hypofunction. The resulting flow rate and electrochemisty of secreted saliva contradicts current understanding of ductal fluid transport. We hypothesized that changes in expression of ion transport proteins have occurred following AQP1 transfection. We use a mathematical model of ion and fluid transport across the parotid duct epithelial cells to predict the expression profile of ion transporters that are consistent with the experimental measurements of saliva composition and secretion rates...
December 8, 2016: American Journal of Physiology. Gastrointestinal and Liver Physiology
Natalie Foot, Tanya Henshall, Sharad Kumar
Newly synthesized transmembrane proteins undergo a series of steps to ensure that only the required amount of correctly folded protein is localized to the membrane. The regulation of protein quality and its abundance at the membrane are often controlled by ubiquitination, a multistep enzymatic process that results in the attachment of ubiquitin, or chains of ubiquitin to the target protein. Protein ubiquitination acts as a signal for sorting, trafficking, and the removal of membrane proteins via endocytosis, a process through which multiple ubiquitin ligases are known to specifically regulate the functions of a number of ion channels, transporters, and signaling receptors...
January 2017: Physiological Reviews
Beatrice Ellen Tyrrell, Andrew Cameron Sayce, Kelly Lyn Warfield, Joanna Louise Miller, Nicole Zitzmann
Influenza virus causes three to five million severe respiratory infections per year in seasonal epidemics, and sporadic pandemics, three of which occurred in the twentieth century and are a continuing global threat. Currently licensed antivirals exclusively target the viral neuraminidase or M2 ion channel, and emerging drug resistance necessitates the development of novel therapeutics. It is believed that a host-targeted strategy may combat the development of antiviral drug resistance. To this end, a class of molecules known as iminosugars, hydroxylated carbohydrate mimics with the endocyclic oxygen atom replaced by a nitrogen atom, are being investigated for their broad-spectrum antiviral potential...
December 8, 2016: Critical Reviews in Microbiology
Kazuki Fukami, Fumiko Sekiguchi, Atsufumi Kawabata
BACKGROUND: Hydrogen sulfide (H2S), a gasotransmitter, is generated from L-cysteine by mainly 3 enzymes, cystathionine-γ-lyase (CSE), cystathionine-β-synthase, and 3-mercaptopyruvate sulfurtransferase in cooperation with cysteine aminotransferase. The H2S-forming enzymes, particularly CSE, are overexpressed under the pathological conditions such as inflammation, neuronal or neuroendocrine differentiation and cancer development. Given that Cav3.2 T-type Ca2+ channels mediate some of the biological activity of H2S, we focus on the role of the H2S/Cav3...
December 9, 2016: Pharmacology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"