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https://www.readbyqxmd.com/read/28538154/effect-of-ca-2-to-sphingomyelin-investigated-by-sum-frequency-generation-vibrational-spectroscopy
#1
Rong-Juan Feng, Lu Lin, Yi-Yi Li, Ming-Hua Liu, Yuan Guo, Zhen Zhang
The interactions between Ca(2+) ions and sphingomyelin play crucial roles in a wide range of cellular activities. However, little is known about the molecular details of the interactions at interfaces. In this work, we investigated the interactions between Ca(2+) ions and egg sphingomyelin (ESM) Langmuir monolayers at the air/water interface by subwavenumber high-resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS). We show that Ca(2+) ions can induce ordering of the acyl chains in the ESM monolayer...
May 23, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28538153/new-continuum-approaches-for-determining-protein-induced-membrane-deformations
#2
David Argudo, Neville P Bethel, Frank V Marcoline, Charles W Wolgemuth, Michael Grabe
The influence of the membrane on transmembrane proteins is central to a number of biological phenomena, notably the gating of stretch activated ion channels. Conversely, membrane proteins can influence the bilayer, leading to the stabilization of particular membrane shapes, topological changes that occur during vesicle fission and fusion, and shape-dependent protein aggregation. Continuum elastic models of the membrane have been widely used to study protein-membrane interactions. These mathematical approaches produce physically interpretable membrane shapes, energy estimates for the cost of deformation, and a snapshot of the equilibrium configuration...
May 23, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28538150/lanthanides-report-calcium-sensor-in-the-vestibule-of-ryanodine-receptor
#3
Sándor Sárközi, István Komáromi, István Jóna, János Almássy
Ca(2+) regulates ryanodine receptor's (RyR) activity through an activating and an inhibiting Ca(2+)-binding site located on the cytoplasmic side of the RyR channel. Their altered sensitivity plays an important role in the pathology of malignant hyperthermia and heart failure. We used lanthanide ions (Ln(3+)) as probes to investigate the Ca(2+) sensors of RyR, because they specifically bind to Ca(2+)-binding proteins and they are impermeable to the channel. Eu(3+)'s and Sm(3+)'s action was tested on single RyR1 channels reconstituted into planar lipid bilayers...
May 23, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28538099/iodide-selective-synthetic-ion-channels-based-on-shape-persistent-organic-cages
#4
Bahiru Punja Benke, Pulakesh Aich, Younghoon Kim, Kyung Lock Kim, Md Rumum Rohman, Soonsang Hong, In-Chul Hwang, Eun Hui Lee, Joon Ho Roh, Kimoon Kim
We report here a synthetic ion channel developed from a shape-persistent porphyrin-based covalent organic cage. The cage was synthesized by employing a synthetically economical dynamic covalent chemistry (DCC) approach. The organic cage selectively transports biologically relevant iodide ions over other inorganic anions by a dehydration-driven, channel mechanism as evidenced by vesicle-based fluorescence assays and planar lipid bilayer-based single channel recordings. Furthermore, the organic cage appears to facilitate iodide transport across the membrane of a living cell, suggesting that the cage could be useful as a biological tool that may replace defective iodide channels in living systems...
May 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28535052/programming-ionic-pore-accessibility-in-zwitterionic-polymer-modified-nanopores
#5
Laura Silies, Annette Andrieu-Brunsen
Creating switchable and gradually tunable pores or channels that display transport control similar to biological pores remains a major challenge in nanotechnology. It requires the generation and manipulation of complex charge situations at the nanoscale and the understanding of how confinement influences chemistry and transport. Here, two different pore sizes, ∼100 nm and less than 10 nm, functionalized with varying amounts of responsive zwitterionic polycarboxybetaine methyl acrylate (PCBMA) give fascinating insight into the confinement controlled ionic transport of pores functionalized with pH-dependent zwitterionic polymers...
May 23, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28534960/cellular-na-handling-mechanisms-involved-in-airway-smooth-muscle-contraction-review
#6
Bettina Sommer, Edgar Flores-Soto, Georgina Gonzalez-Avila
A decrease in bronchial diameter is designated as bronchoconstriction (BC) and impedes the flow of air through the airway. Asthma is characterized by inflammation of the airways, reversible BC and nonspecific hyperreactivity. These last two symptoms are dependent on airway smooth muscle. Stimuli that trigger contraction can be characterized as chemical (neurotransmitters, cytokines and terpenoids) and physical (volume inspired, air pressure). Both stimuli activate signaling pathways by acting on membrane proteins and facilitating the passage of ions through the membrane, generating a voltage change and a subsequent depolarization...
May 17, 2017: International Journal of Molecular Medicine
https://www.readbyqxmd.com/read/28534587/light-induced-relaxation-dynamics-of-the-ferricyanide-ion-revisited-by-ultrafast-xuv-photoelectron-spectroscopy
#7
Nicholas Engel, Sergey I Bokarev, Alexandre Moguilevski, Azhr A Raheem, Ruba Al-Obaidi, Tobias Möhle, Gilbert Grell, Katrin R Siefermann, Bernd Abel, Saadullah G Aziz, Oliver Kühn, Mario Borgwardt, Igor Yu Kiyan, Emad F Aziz
Photoinduced charge transfer in transition-metal coordination complexes plays a prominent role in photosynthesis and is fundamental for light-harvesting processes in catalytic materials. However, revealing the relaxation pathways of charge separation remains a very challenging task because of the complexity of relaxation channels and ultrashort time scales. Here, we employ ultrafast XUV photoemission spectroscopy to monitor fine mechanistic details of the electron dynamics following optical ligand-to-metal charge-transfer excitation of ferricyanide in aqueous solution...
May 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28534204/-ventricular-arrhythmias-in-ion-channel-diseases
#8
REVIEW
Christian Wolpert, Mara Vogel, Christian Nagel, Claudia Herrera-Siklody, Norman Rüb
In patients with ion channel disease the predominant arrhythmias are polymorphic ventricular tachycardias (VT), torsade de pointes tachycardia and ventricular fibrillation (VF). In only extremely rare cases is very rapid monomorphic ventricular tachycardia observed. This is why implantable cardioverter-defibrillators (ICDs) should always be programmed for treatment of VF only with high detection rates to avoid inappropriate discharges. In idiopathic VF and catecholaminergic polymorphic ventricular tachycardia (CPVT), no baseline electrocardiographic abnormalities can be detected, whereas in Brugada syndrome, long QT syndrome, early repolarisation syndrome and Anderson-Tawil syndrome alterations of the baseline ECG are very important to identify patients at risk...
May 22, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28534085/atp-induced-ca-2-signalling-mechanisms-in-the-regulation-of-mesenchymal-stem-cell-migration
#9
REVIEW
Lin-Hua Jiang, Fatema Mousawi, Xuebin Yang, Sėbastien Roger
The ability of cells to migrate to the destined tissues or lesions is crucial for physiological processes from tissue morphogenesis, homeostasis and immune responses, and also for stem cell-based regenerative medicines. Cytosolic Ca(2+) is a primary second messenger in the control and regulation of a wide range of cell functions including cell migration. Extracellular ATP, together with the cognate receptors on the cell surface, ligand-gated ion channel P2X receptors and a subset of G-protein-coupled P2Y receptors, represents common autocrine and/or paracrine Ca(2+) signalling mechanisms...
May 22, 2017: Cellular and Molecular Life Sciences: CMLS
https://www.readbyqxmd.com/read/28533270/classical-activation-of-macrophages-and-vardenafil
#10
Richmond Muimo
Inhibitors of phosphodiesterase 5 (PDE5) - sildenafil citrate (Viagra; Pfizer) and vardenafil hydrochloride (Levitra; Bayer/GlaxoSmithKline) - approved for the treatment of erectile dysfunction and pulmonary arterial hypertension also rescue the loss of cystic fibrosis (CF) chloride channel function and the mislocalization of F508del-CFTR in affected tissues in CF. Can PDE5 inhibitors provide a therapeutic strategy which combines ability to correct the basic ion transport defect and to control de-regulated lung inflammation in CF?...
June 1, 2017: Clinical Science (1979-)
https://www.readbyqxmd.com/read/28533165/analgesic-conopeptides-targeting-g-protein-coupled-receptors-reduce-excitability-of-sensory-neurons
#11
REVIEW
Mahsa Sadeghi, Jeffrey R McArthur, Rocio K Finol-Urdaneta, David J Adams
Conotoxins (conopeptides) are a diverse group of peptides isolated from the venom of marine cone snails. Conus peptides modulate pain by interacting with voltage-gated ion channels and G protein-coupled receptors (GPCRs). Opiate drugs targeting GPCRs have long been used, nonetheless, many undesirable side effects associated with opiates have been observed including addiction. Consequently, alternative avenues to pain management are a largely unmet need. It has been shown that various voltage-gated calcium channels (VGCCs) respond to GPCR modulation...
May 19, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28532668/design-synthesis-and-biological-evaluation-of-4-piperazinyl-containing-chidamide-derivatives-as-hdacs-inhibitors
#12
Qingwei Zhang, Bingliu Lu, Jianqi Li
The synthesis and biological evaluation of a variety of 4-piperazinyl-containing Chidamide derivatives is described. Some of these compounds were shown to inhibit HDAC1 with IC50 values below micromolar range, and inhibited proliferation of several human cancer cells, not possessing toxicity to human normal cells and hERG K(+) ion channels. Compound 9g, proved to be the most potent and efficacious derivative in this series, was orally active in an HCT116 xenograft model in vivo.
May 12, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28530274/transporting-an-ionic-liquid-water-mixture-in-a-conical-nanochannel-a-nanofluidic-memristor
#13
Qian Sheng, Yanbo Xie, Jun Li, Xinwei Wang, Jianming Xue
Synthetic conical nanochannels have gained attention for their ion rectification behavior, which can be used to mimic the functionalities of biological ion channels. Employing these nanochannels and inspired by biological synaptic dynamics, we herein demonstrate a new nanofluidic device as a memristor, the ion transport conductance of which depends on the history of its ion flow. The nanofluidic memristors show excellent repeatability, high ON/OFF ratios, and sufficiently long retention times, which are highly desirable for logic control and neuromorphic engineering applications in nanofluidic systems as well as for fundamental transport studies of ionic liquids on a nanoscale...
May 22, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28530239/thermogenetic-neurostimulation-with-single-cell-resolution
#14
Yulia G Ermakova, Aleksandr A Lanin, Ilya V Fedotov, Matvey Roshchin, Ilya V Kelmanson, Dmitry Kulik, Yulia A Bogdanova, Arina G Shokhina, Dmitry S Bilan, Dmitry B Staroverov, Pavel M Balaban, Andrei B Fedotov, Dmitry A Sidorov-Biryukov, Evgeny S Nikitin, Aleksei M Zheltikov, Vsevolod V Belousov
Thermogenetics is a promising innovative neurostimulation technique, which enables robust activation of neurons using thermosensitive transient receptor potential (TRP) cation channels. Broader application of this approach in neuroscience is, however, hindered by a limited variety of suitable ion channels, and by low spatial and temporal resolution of neuronal activation when TRP channels are activated by ambient temperature variations or chemical agonists. Here, we demonstrate rapid, robust and reproducible repeated activation of snake TRPA1 channels heterologously expressed in non-neuronal cells, mouse neurons and zebrafish neurons in vivo by infrared (IR) laser radiation...
May 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28529713/gap-junction-structure-unraveled-but-not-fully-revealed
#15
REVIEW
Eric C Beyer, Viviana M Berthoud
Gap junction channels facilitate the intercellular exchange of ions and small molecules, a process that is critical for the function of many different kinds of cells and tissues. Recent crystal structures of channels formed by one connexin isoform (connexin26) have been determined, and they have been subjected to molecular modeling. These studies have provided high-resolution models to gain insights into the mechanisms of channel conductance, molecular permeability, and gating. The models share similarities, but there are some differences in the conclusions reached by these studies...
2017: F1000Research
https://www.readbyqxmd.com/read/28529489/the-electrogenic-na-k-pump-is-a-key-determinant-of-repolarization-abnormality-susceptibility-in-human-ventricular-cardiomyocytes-a-population-based-simulation-study
#16
Oliver J Britton, Alfonso Bueno-Orovio, László Virág, András Varró, Blanca Rodriguez
Background: Cellular repolarization abnormalities occur unpredictably due to disease and drug effects, and can occur even in cardiomyocytes that exhibit normal action potentials (AP) under control conditions. Variability in ion channel densities may explain differences in this susceptibility to repolarization abnormalities. Here, we quantify the importance of key ionic mechanisms determining repolarization abnormalities following ionic block in human cardiomyocytes yielding normal APs under control conditions...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28528699/steps-toward-maturation-of-embryonic-stem-cell-derived-cardiomyocytes-by-defined-physical-signals
#17
Nian Shen, Anne Knopf, Claas Westendorf, Udo Kraushaar, Julia Riedl, Hannah Bauer, Simone Pöschel, Shannon Lee Layland, Monika Holeiter, Stefan Knolle, Eva Brauchle, Ali Nsair, Svenja Hinderer, Katja Schenke-Layland
Cardiovascular disease remains a leading cause of mortality and morbidity worldwide. Embryonic stem cell-derived cardiomyocytes (ESC-CMs) may offer significant advances in creating in vitro cardiac tissues for disease modeling, drug testing, and elucidating developmental processes; however, the induction of ESCs to a more adult-like CM phenotype remains challenging. In this study, we developed a bioreactor system to employ pulsatile flow (1.48 mL/min), cyclic strain (5%), and extended culture time to improve the maturation of murine and human ESC-CMs...
May 18, 2017: Stem Cell Reports
https://www.readbyqxmd.com/read/28528673/acid-sensing-ion-channel-pharmacology-past-present-and-future-%C3%A2
#18
Lachlan D Rash
pH is one of the most strictly controlled parameters in mammalian physiology. An extracellular pH of ~7.4 is crucial for normal physiological processes, and perturbations to this have profound effects on cell function. Acidic microenvironments occur in many physiological and pathological conditions, including inflammation, bone remodeling, ischemia, trauma, and intense synaptic activity. Cells exposed to these conditions respond in different ways, from tumor cells that thrive to neurons that are either suppressed or hyperactivated, often fatally...
2017: Advances in Pharmacology
https://www.readbyqxmd.com/read/28528672/physiology-and-pharmacology-of-ryanodine-receptor-calcium-release-channels
#19
Angela F Dulhunty, Philip G Board, Nicole A Beard, Marco G Casarotto
Ryanodine receptor (RyR) ion channels are essential for skeletal and cardiac muscle function. Their knockout leads to perinatal death from respiratory and cardiac failure. Acquired changes or mutations in the protein cause debilitating skeletal myopathy and cardiac arrhythmia which can be deadly. Knowledge of the pharmacology of RyR channels is central to developing effective and specific treatments of these myopathies. The ion channel is a >2.2MDa homotetamer with distinct structural and functional characteristics giving rise to a myriad of regulatory sites that are potential therapeutic targets...
2017: Advances in Pharmacology
https://www.readbyqxmd.com/read/28528671/voltage-gated-sodium-channel-pharmacology-insights-from-molecular-dynamics-simulations
#20
Rong Chen, Amanda Buyan, Ben Corry
Voltage-gated ion channels are the target of a range of naturally occurring toxins and therapeutic drugs. There is a great interest in better understanding how these diverse compounds alter channel function in order to design the next generation of therapeutics that can selectively target one of the channel subtypes found in the body. Since the publication of a number of bacterial sodium channel structures, molecular dynamics simulations have been invaluable in gaining a high resolution understanding where many of these small molecules and toxins bind to the channels, how they find their binding site, and how they can selectively bind to one channel subtype over another...
2017: Advances in Pharmacology
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