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Ion transporters

Jianjun Chang, Yan Ding, Zhiyu Zhou, Hong-Guang Nie, Hong-Long Ji
Transepithelial fluid and salt re-absorption in epithelial tissues play an important role in fluid and salt homeostasis. In absorptive epithelium, fluid and salt flux is controlled by machinery mainly composed of epithelial sodium channels (ENaC), cystic fibrosis transmembrane conductance regulator (CFTR), Na⁺/H⁺ exchanger (NHE), aquaporin, and sodium potassium adenosine triphosphatase (Na⁺/K⁺-ATPase). Dysregulation of fluid and salt transport across epithelium contributes to the pathogenesis of many diseases, such as pulmonary edema and cystic fibrosis...
March 16, 2018: International Journal of Molecular Sciences
Oriol Blázquez, Gemma Martín, Ivan Camps, Antonio Mariscal, Julian López-Vidrier, Joan Manel Ramirez, Sergi Hernández, Sonia Estrade, Francesca Peiro, Rosalía Serna, Blas Garrido
The resistive switching properties of silicon-aluminium oxynitride (SiAlON) based devices have been studied. Electrical transport mechanisms at both resistance states were determined, exhibiting an ohmic behaviour at low resistant state and a defect-related Poole-Frenkel mechanism at high resistant state. Nevertheless, some features on the Al top-electrode are generated during the initial electroforming, suggesting some material modifications. An in-depth microscopic study at the nanoscale have been performed after the electroforming process, by acquiring scanning electron microscopy and transmission electron microscopy images...
March 16, 2018: Nanotechnology
Domenique D Zomer-van Ommen, Eyleen de Poel, Evelien Kruisselbrink, Hugo Oppelaar, Annelotte M Vonk, Hettie M Janssens, Cornelis K van der Ent, Marne C Hagemeijer, Jeffrey M Beekman
BACKGROUND: New functional assays using primary human intestinal adult stem cell cultures can be valuable tools to study epithelial defects in human diseases such as cystic fibrosis. METHODS: CFTR-mediated ion transport was measured in rectal organoid-derived monolayers grown from subjects with various CFTR mutations and compared to donor-matched intestinal current measurements (ICM) in rectal biopsies and forskolin-induced swelling of rectal organoids. RESULTS: Rectal organoid-derived monolayers were generated within four days...
March 13, 2018: Journal of Cystic Fibrosis: Official Journal of the European Cystic Fibrosis Society
H A Alhazmi
Transferrin is iron (III)-binding protein that transports Fe (III) ion to cells in different parts of the body. At saturation level 70% of transferrin remains free from iron (apo-transferrin), suggesting a broader scope of binding capabilities with non-iron (III) metal ions. Our previous work demonstrated that transferrin can effectively coordinate with noble metal ions. Hence to improve our understanding of the in-vitro metal-interaction behavior of the protein and how it correlates with its functions invivo, the interactions between apo-transferrin and medicinally important noble metals, Au (I), Au (III), Os (III), Pt (IV), Ir (III) and Ru (III) were investigated in the mobility shift mode of affinity capillary electrophoresis...
March 5, 2018: Die Pharmazie
Pouyan Ebrahimi, Javier Vilcáez
This research aimed to elucidate the effect of brine salinity and guar gum on the sorption and transport of Ba in dolomite rocks collected from the Arbuckle formation in Oklahoma, USA. Guar gum represents the most important organic additive used in viscosified fracturing fluids, and Ba constitutes the most common and abundant heavy metal found in unconventional oil and gas (UOG) wastewater. Batch experiments conducted using powdered dolomite rocks (500-600 μm particle size) revealed that at brine salinities of UOG wastewater, chloro-complexation reactions between Ba and Cl ions and pH changes that results from dolomite dissolution are the controlling factors of Ba sorption on dolomite...
March 12, 2018: Journal of Environmental Management
Yancong Feng, Rui Tan, Yan Zhao, Rongtan Gao, Luyi Yang, Jinlong Yang, Hao Li, Guofu Zhou, Haibiao Chen, Feng Pan
A novel hybrid single Li-ion conductor (SLIC) for a Li-ion solid electrolyte was prepared by mixing aluminate complexes-polyethylene glycol (LiAl-PEG) and polyethylene oxide (PEO) for solid-state Li-ion batteries. The LiAl-PEG/PEO blend possesses high thermal stability and electrochemical stability with an oxidation decomposition voltage up to 4.8 V. Notably, this hybrid SLIC exhibits not only excellent Li-ion migration kinetics, but also good ionic conductivity as high as 4.0 × 10-5 and 2.6 × 10-4 S cm-1 at 30 and 100 °C, respectively, which is much higher than previously reported SLICs...
March 15, 2018: Nanoscale
Bingwen Zhang, Qinfang Zhang, Yujie Bai
A new monolayer MnC<sub>2</sub> was predicted as a stable 2D material associated with the
 result of phonon and AIMD calculations. The in-plane young's modulus is 73.6 N/m,
 which is about 20% of graphene. The monolayer MnC<sub>2</sub> is antiferromagnetic with a
 Neil temperature around 280K and from the dirac point of the electronic band we got
 the fermi velocity of 5.37×10<sup>5</sup> m/s showing excellent electronic transport property...
March 15, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Justine Marchand, Parisa Heydarizadeh, Benoît Schoefs, Cornelia Spetea
Chloroplasts are endosymbiotic organelles and play crucial roles in energy supply and metabolism of eukaryotic photosynthetic organisms (algae and land plants). They harbor channels and transporters in the envelope and thylakoid membranes, mediating the exchange of ions and metabolites with the cytosol and the chloroplast stroma and between the different chloroplast subcompartments. In secondarily evolved algae, three or four envelope membranes surround the chloroplast, making more complex the exchange of ions and metabolites...
March 14, 2018: Cellular and Molecular Life Sciences: CMLS
Cuimei Zhang, Shangli Shi
Drought severely limits global plant distribution and agricultural production. Elucidating the physiological and molecular mechanisms governing alfalfa stress responses will contribute to the improvement of drought tolerance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa ( Medicago sativa L.) varieties contrasting in drought tolerance, Longzhong (drought-tolerant) and Gannong No. 3 (drought-sensitive), were comparatively assayed when seedlings were exposed to -1...
2018: Frontiers in Plant Science
Ganhua Xie, Pei Li, Zhiju Zhao, Zhongpeng Zhu, Xiang-Yu Kong, Zhen Zhang, Kai Xiao, Liping Wen, Lei Jiang
Water wetting behavior in nano-confined environments plays an important role in mass transport and signal trans-mission of organisms. It is valuable and challengeable to investigate how water behaves in such a nanometer-scale with external stimuli, in particular with electric field and light. Unfortunately, the mechanism of hydrophobic reaction inside the nano-spaces is still obscure and lacks of experimental supporting for the current electric-field- or photo-responsive nanochannels which suffer from fragility or monofunctionality...
March 15, 2018: Journal of the American Chemical Society
Mohammad Kassem, Igor Alekseev, Maria Escorne-Bokova, David Le Coq, Eugene Bychkov
Conductivity isotherms of (CdTe)x (AgI)0.5- x/2 (As2Te3)0.5- x/2 glasses (0.0 ≤ x ≤ 0.15) reveal a non-monotonic behavior with increasing CdTe content reminiscent of mixed cation effect in oxide and chalcogenide glasses. Nevertheless, the apparent similarity appears to be partly incorrect. Using110m Ag tracer diffusion measurements, we show that semiconducting CdTe additions produce a dual effect: (1) decreasing the Ag+ ion transport by a factor of ≈200 with a simultaneous increase of the diffusion activation energy, and (2) increasing the electronic conductivity by 1...
March 14, 2018: Journal of Physical Chemistry. B
Ning Wei, Michelle L Gumz, Anita T Layton
Major renal functions such as renal blood flow, glomerular filtration rate, and urinary excretion are known to exhibit circadian oscillations. However, the underlying mechanisms that govern these variations have yet to be fully elucidated. To better understand the impact of the circadian clock on renal solute and water transport, we have developed a computational model of the renal circadian clock, and coupled that model to an epithelial transport model of the proximal convoluted cell of the rat kidney. The activity of the Na$^+$-H$^+$ exchanger 3 (NHE3) is assumed to be regulated by changes in transcription of the NHE3 mRNA due to regulation by circadian clock proteins...
March 14, 2018: American Journal of Physiology. Renal Physiology
Vatika Gupta, Kanika Jain, Rajni Garg, Anshu Malik, Pooja Gulati, Rakesh Bhatnagar
Microbial colonization is an outcome of appropriate sensing and regulation of its gene expression. Bacillus anthracis adapts and thrives in its environment through complex regulatory mechanisms, among them, the two component systems (TCS). Many bacteria respond to the oxygen fluctuations via TCS. In the present work, a previously uncharacterized TCS, Bas1213-1214, of B. anthracis with a probable role in oxygen sensing has been characterized as a functional TCS. A substantial increase in the expression of Bas1213 was observed during the stationary growth phase, in presence of bicarbonate ions, and under oxidative stress thereby speculating the role of Bas1213 in toxin production and adaptive responses...
March 14, 2018: Journal of Cellular Biochemistry
Arisu Shigeta, Shota Ito, Rina Kaneko, Sahoko Tomida, Keiichi Inoue, Hideki Kandori, Izuru Kawamura
Krokinobacter rhodopsin 2 (KR2), a light-driven Na+ pump, is a dual-functional protein, pumping protons in the absence of Na+ when K+ or larger alkali metal ions are present. A specific mutation in helix A near the extracellular Na+ binding site, H30A, eliminates its proton pumping ability. We induced structural changes in H30A by altering the alkali metal ion bound at the extracellular binding site, and observed a strong electrostatic interaction between the Schiff base and counterion and torsion around the Schiff base as revealed by solid-state nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies...
March 14, 2018: Physical Chemistry Chemical Physics: PCCP
Zheng-Zhe Zhang, Ya-Fei Cheng, Lian-Zeng-Ji Xu, Yu-Hui Bai, Ren-Cun Jin
The increasing use of engineered Ag nanoparticles (NPs) in consumer products raises great concerns about their environmental impacts, but their potential impact on anaerobic ammonium oxidation (anammox) bacteria in wastewater treatment remains unclear. In this study, the response of anammox consortia inhabiting in granules to long-term exposure of AgNPs was investigated. The gradually increased stress of AgNPs (1, 10, 50 mg L-1 ) showed no adverse effects on the nitrogen removal performance and on the relative abundance of Ca...
March 7, 2018: Bioresource Technology
L V Tat'yanenko, N A Sanina, O V Dobrokhotova, A I Kotelnikov, N S Goryachev, I I Pihteleva, G I Kozub, T A Kondrateva
The effect of iron nitrosyl complexes, NO donors, of a general formula [Fe2 (L)2 (NO)4 ] with functional sulfur-containing ligands (L-3-nitro-phenol-2-yl, 4-nitro-phenol-2-yl, or 1-methyl-tetrazol-5-yl) on the activity of sarcoplasmic reticulum Ca2+ -ATPase and cyclic guanosine monophosphate phosphodiesterase (cGMP PDE) was studied. The test complexes uncoupled the hydrolytic and transport functions of Ca2+ - ATPase, thus disturbing the balance of Ca2+ ions in cells, which may affect the formation of thrombi and adhesion of metastatic cells to the endothelium of capillaries...
January 2018: Doklady. Biochemistry and Biophysics
Shoji Segami, Mariko Asaoka, Satoru Kinoshita, Mayu Fukuda, Yoichi Nakanishi, Masayoshi Maeshima
Proton-translocating inorganic pyrophosphatase (H+-PPase) actively translocates protons across membranes coupled with the hydrolysis of inorganic pyrophosphate (PPi). H+-PPase, which is composed of a single protein and uses a simple compound as a substrate, has been recognized as a new type of ion pump in addition to the P-, F-, and V-type ion translocating ATPases. H+- and Na+-PPases are distributed in various organisms including plants, parasitic protozoa, Archaebacteria, and bacteria, but are not present in animals or yeast...
March 9, 2018: Plant & Cell Physiology
A Mostek, M Slowinska, S Judycka, H Karol, A Ciereszko, M A Dietrich
During semen cryopreservation, spermatozoa are exposed to physical and chemical stressors that result in their functional and structural damage. Growing evidence suggests that most cryoinjuries result from oxidative stress accompanying sperm cryopreservation. Elevated amounts of reactive oxygen species (ROS) generated during cryopreservation can react with sperm macromolecules, including proteins. The goal of this study was to investigate the oxidative modifications (measured as carbonylation level changes) of carp spermatozoa proteins triggered by the cryopreservation process...
March 9, 2018: Journal of Animal Science
Sunhye Kim, Tae-Young Kim, Seung-Muk Yi, Jongbae Heo
The sources of different pollutants contributing to ambient fine particles (PM2.5 ) on Daebu Island, Korea, were estimated. Twenty four hour integrated filter samples were collected from May 21-November 1, 2016, and analyzed for organic carbon, elemental carbon, ions, and trace elements. Positive matrix factorization was conducted on the PM2.5 chemical speciation data from the samples to define the pathways and sources of PM2.5 at the sampling site. A total of 80 samples and 24 chemical species were used to run the model and a total of nine sources were identified: secondary sulfate (29...
March 10, 2018: Journal of Environmental Management
Sherwood Benavides, Siyi Qu, Feng Gao, William A Phillip
The development of membranes that separate molecules based on chemical factors, rather than physical factors, is one promising approach to meeting the demand for membranes that are more selective. In this study, the design of multifunctional, pH-responsive membranes that selectively pump a target solute is detailed. The membranes consist of two functional components: a gate layer made from an amine-functionalized copolymer and a reactive matrix lined by iminodiacetic acid groups that bind divalent cations reversibly...
March 13, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
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