Function Of Cl Research Articles

Stimulatory effect of vascular endothelial growth factor on progesterone production and survivability of cultured bubaline luteal cells

The objectives of the present study were to investigate the effects of vascular endothelial growth factor (VEGF) on progesterone (P4) synthesis in cultured luteal cells from different stages of the estrous cycle and on expression of steroidogenic acute regulatory protein (STARD1), cytochrome P450 cholesterol side chain cleavage (CYP11A1) and 3β-hydroxysteroid dehydrogenase (HSD3B), antiapoptotic gene PCNA, and proapoptotic gene BAX in luteal cells obtained from mid-luteal phase (MLP) of estrous cycle in buffalo. Corpus luteum samples from the early luteal phase (ELP; day 1st–4th; n=4), MLP (day 5th–10th; n=4), and the late luteal phase (LLP; day 11th–16th; n=4) of oestrous cycle were obtained from a slaughterhouse. Luteal cell cultures were treated with VEGF (0, 1, 10 and 100ng/ml) for 24, 48 and 72h. Progesterone was assessed by RIA, while mRNA expression was determined by quantitative real-time PCR (qRT-PCR). Results indicated a dose- and time-dependent stimulatory effect of VEGF on P4 synthesis and expression of steroidogenic enzymes. Moreover, VEGF treatment led to an increase in PCNA expression and decrease in BAX expression. In summary, these findings suggest that VEGF acts locally in the bubaline CL to modulate steroid hormone synthesis and cell survivability, which indicates that this factor has an important role as a regulator of CL development and function in buffalo.

Ovulation-inducing factor (OIF/NGF) from seminal plasma origin enhances Corpus Luteum function in llamas regardless the preovulatory follicle diameter

Ovulation-inducing factor (OIF) is a protein present in llama seminal plasma that has recently been identified as β-Nerve Growth Factor (NGF) and it induces not only a high rate of ovulation but also appears to have luteotrophic properties in this species. A 2-by-2 experimental design was used to determine the effect of treatments (OIF/NGF vs GnRH) and categories of preovulatory follicle diameter (7–10 vs >10mm) on ovulation rate, CL diameter and function in llamas. Llamas (n=32 llamas per group) were randomly assigned to receive an intramuscular dose of: (a) 1mg purified OIF/NGF in the presence of a follicle of 7–10mm in diameter; (b) 50μg of GnRH in the presence of a follicle of 7–10mm in diameter; (c) 1mg purified OIF/NGF in the presence of a follicle >10mm in diameter; (d) 50μg of GnRH in the presence of a follicle >10mm in diameter. Llamas were examined by ultrasonography every 12h from treatment to Day 2 (Day 0=treatment) to detect ovulation, and again on Day 8 to determine CL diameter. Ovulation rates did not differ among groups. There was an effect of preovulatory follicle size on Corpus Luteum diameter at Day 8 (P<0.001), however plasma progesterone concentration (n=15/per group) was higher (P<0.05) in the OIF/NGF – than that of the GnRH – treated group by the same day. We conclude that OIF/NGF treatment enhances CL function regardless preovulatory follicle size at the time of treatment.

The G551D CFTR chloride channel spurs the development of personalized medicine.

The G551D CFTR chloride channel spurs the development of personalized medicine.

Downregulation of Chloride Channel ClC-2 by Janus Kinase 3

Janus kinase-3 (JAK3) fosters proliferation and counteracts apoptosis of lymphocytes and tumor cells. The gain of function mutation (A572V)JAK3 has been discovered in acute megakaryoplastic leukemia. JAK3 is inactivated by replacement of lysine by alanine in the catalytic subunit ((K855A)JAK3). Regulation of cell proliferation and apoptosis involves altered activity of Cl(-) channels. The present study, thus, explored whether JAK3 modifies the function of the small conductance Cl(-) channel ClC-2. To this end, ClC-2 was expressed in Xenopus oocytes with or without wild-type JAK3, (A568V)JAK3 or (K851A)JAK3, and the Cl(-) channel activity determined by dual-electrode voltage clamp. Channel protein abundance in the cell membrane was determined utilizing chemiluminescence. As a result, expression of ClC-2 was followed by a marked increase of cell membrane conductance. The conductance was significantly decreased following coexpression of JAK3 or (A568V)JAK3, but not by coexpression of (K851A)JAK3. Exposure of the oocytes expressing ClC-2 together with (A568V)JAK3 to the JAK3 inhibitor WHI-P154 (4-[(3'-bromo-4'-hydroxyphenyl)amino]-6,7-dimethoxyquinazoline, 22μM) increased the conductance. Coexpression of (A568V)JAK3 decreased the ClC-2 protein abundance in the cell membrane of ClC-2 expressing oocytes. The decline of conductance in ClC-2 and (A568V)JAK3 coexpressing oocytes following inhibition of channel protein insertion by brefeldin A (5μM) was similar in oocytes expressing ClC-2 with (A568V)JAK3 and oocytes expressing ClC-2 alone, indicating that (A568V)JAK3 might slow channel protein insertion into rather than accelerating channel protein retrieval from the cell membrane. In conclusion, JAK3 downregulates ClC-2 activity and thus counteracts Cl(-) exit-an effect possibly influencing cell proliferation and apoptosis.

Change of the work function of platinum electrodes induced by halide adsorption

The properties of a halogen-covered platinum(111) surface have been studied by using density functional theory (DFT), because halides are often present at electrochemical electrode/electrolyte interfaces. We focused in particular on the halogen-induced work function change as a function of the coverage of fluorine, chlorine, bromine and iodine. For electronegative adsorbates, an adsorption-induced increase of the work function is usually expected, yet we find a decrease of the work function for Cl, Br and I, which is most prominent at a coverage of approximately 0.25 ML. This coverage-dependent behavior can be explained by assuming a combination of charge transfer and polarization effects on the adsorbate layer. The results are contrasted to the adsorption of fluorine on calcium, a system in which a decrease in the work function is also observed despite a large charge transfer to the halogen adatom.

Development of a Corrosion Model to Correlate the Atmospheric Corrosion Rate of a Carbon-Fiber Reinforced Aluminum MMC to Weather and Environmental Parameters

A corrosion model was developed to correlate the atmospheric corrosion rates of 50 volume% nickel (Ni)-coated carbon (C) fiber reinforced pure aluminum (Al (99.99%)/C/50f) metal-matrix composites (MMCs) to weather and environmental parameters such as chloride (Cl−) deposition rate, aerosol pH, and the percentage of time wet (Q4). The model was developed using polarization data of Al and C in solutions of various pH levels and Cl− concentrations. The polarization data indicated that the galvanic corrosion current (igalv) between Al and C is a function of Cl− concentration and pH. There was a linear relationship between the logarithm of igalv and the logarithm of Cl− concentrations in neutral solutions with an R2 value close to 0.95. Using the linear relationship, a corrosion model was developed that estimated the atmospheric corrosion rate of Al (99.99%)/50 MMCs as a function of the Cl− deposition rate and Q4 (i.e., [Cl‑]K•Q4), where K is the slope of the log (igalv) vs log (Cl−) curve. The atmospheric corrosion rates of Al (99.99%)/C/50f MMCs in marine, rain forest, agricultural, dry, and industrial test sites in Hawai’i were plotted against the model ([Cl−]K•Q4), which resulted in an R2 value equal to approximately 0.7.

Analytical Evaluation of Time-to-Corrosion for Chloride-Exposed Reinforced Concrete with an Admixed Corrosion Inhibitor: Part 1—No Inhibitor Egress

A first-principles-based equation from the literature was modified such that the cumulative distribution function (CDF) of Cl− concentration ([Cl−]) in concrete at the reinforcement depth after a given exposure time was calculated by numerical integration. The approach accommodates the fact that surface Cl− concentration (Cs), the effective diffusion coefficient (D), and reinforcement cover (x) each conform to a distribution, rather than being discreet. Calculations were performed for a range of mean D, Cs, and x values. The previously reported limiting [Cl−] for which various dosages of the corrosion inhibitor calcium nitrite (CN) are effective in maintaining reinforcing steel passivity was superimposed upon the CDF. From probability distributions of, first, [Cl−] and, second, Cl− threshold to initiate active corrosion, as enhanced by a particular CN addition, the percentage of reinforced concrete elements for which active corrosion initiates after specific times and, hence, inhibitor effectiveness, were...

Critical role of bicarbonate and bicarbonate transporters in cardiac function.

Bicarbonate is one of the major anions in mammalian tissues and extracellular fluids. Along with accompanying H(+), HCO3 (-) is generated from CO2 and H2O, either spontaneously or via the catalytic activity of carbonic anhydrase. It serves as a component of the major buffer system, thereby playing a critical role in pH homeostasis. Bicarbonate can also be utilized by a variety of ion transporters, often working in coupled systems, to transport other ions and organic substrates across cell membranes. The functions of HCO3 (-) and HCO3 (-)-transporters in epithelial tissues have been studied extensively, but their functions in heart are less well understood. Here we review studies of the identities and physiological functions of Cl(-)/HCO3 (-) exchangers and Na(+)/HCO3 (-) cotransporters of the SLC4A and SLC26A families in heart. We also present RNA Seq analysis of their cardiac mRNA expression levels. These studies indicate that slc4a3 (AE3) is the major Cl(-)/HCO3 (-) exchanger and plays a protective role in heart failure, and that Slc4a4 (NBCe1) is the major Na(+)/HCO3 (-) cotransporter and affects action potential duration. In addition, previous studies show that HCO3 (-) has a positive inotropic effect in the perfused heart that is largely independent of effects on intracellular Ca(2+). The importance of HCO3 (-) in the regulation of contractility is supported by experiments showing that isolated cardiomyocytes exhibit sharply enhanced contractility, with no change in Ca(2+) transients, when switched from Hepes-buffered to HCO3 (-)- buffered solutions. These studies demonstrate that HCO3 (-) and HCO3 (-)-handling proteins play important roles in the regulation of cardiac function.

Novel luteolytic mechanisms in equine corpora lutea: the role of Nodal signaling pathway and its interaction with Tumor necrosis factor alpha, Interferon gamma and Fas ligand

Novel luteolytic mechanisms in equine corpora lutea: the role of Nodal signaling pathway and its interaction with Tumor necrosis factor alpha, Interferon gamma and Fas ligand

Preparation of functionalized and metal-impregnated activated carbon by a single-step activation method

A rapid method to prepare functionalized and metal-impregnated activated carbon from coal is described in this paper. A mixture of ferric chloride and a sub-bituminous coal was used to demonstrate simultaneous coal activation, chlorine functionalization, and iron/iron oxides impregnation in the resulting porous carbon products. The FeCl3 concentration in the mixture, the method to prepare the FeCl3-coal mixture (solid mixing or liquid impregnation), and activation atmosphere and temperature impacted the surface area and porosity development, Cl functionalization, and iron species impregnation and dispersion in the carbon products. Samples activated in nitrogen or a simulated flue gas at 600 or 1000°C for 1–2min had surface areas up to ∼800m2/g, bulk iron contents up to 18wt%, and surface chlorine contents up to 27wt%. Potential catalytic and adsorption application of the carbon materials was explored in catalytic wet air oxidation (CWAO) of phenol and adsorption of ionic mercury from aqueous solutions. Results indicated that impregnated activated carbons outperformed their non-impregnated counterparts in both the CWAO and adsorption tests.

TMEM16A knockdown abrogates two different Ca2+-activated Cl− currents and contractility of smooth muscle in rat mesenteric small arteries

The presence of Ca2+-activated Cl− channels (CaCCs) in vascular smooth muscle cells (SMCs) is well established. Their molecular identity is, however, elusive. Two distinct Ca2+-activated Cl− currents (I Cl(Ca)) were previously characterized in SMCs. We have shown that the cGMP-dependent I Cl(Ca) depends on bestrophin expression, while the “classical” I Cl(Ca) is not. Downregulation of bestrophins did not affect arterial contraction but inhibited the rhythmic contractions, vasomotion. In this study, we have used in vivo siRNA transfection of rat mesenteric small arteries to investigate the role of a putative CaCC, TMEM16A. Isometric force, [Ca2+]i, and SMC membrane potential were measured in isolated arterial segments. I Cl(Ca) and GTPγS-induced nonselective cation current were measured in isolated SMCs. Downregulation of TMEM16A resulted in inhibition of both the cGMP-dependent I Cl(Ca) and the “classical” I Cl(Ca) in SMCs. TMEM16A downregulation also reduced expression of bestrophins. TMEM16A downregulation suppressed vasomotion both in vivo and in vitro. Downregulation of TMEM16A reduced agonist (noradrenaline and vasopressin) and K+-induced contractions. In accordance with the depolarizing role of CaCCs, TMEM16A downregulation suppressed agonist-induced depolarization and elevation in [Ca2+]i. Surprisingly, K+-induced depolarization was unchanged but Ca2+ entry was reduced. We suggested that this is due to reduced expression of the L-type Ca2+ channels, as observed at the mRNA level. Thus, the importance of TMEM16A for contraction is, at least in part, independent from membrane potential. This study demonstrates the significance of TMEM16A for two SMCs I Cl(Ca) and vascular function and suggests an interaction between TMEM16A and L-type Ca2+ channels.

Observation of Room Temperature B–Cl Activation of the HCB11Cl11– Anion and Isolation of a Stable Anionic Carboranyl Phosphazide

The perchlorinated carba-closo-dodecaborate anion is typically inert toward B-Cl functionalization. We present here the observation of two competing reactions that occur with this anion at ambient temperature. When this molecule is treated with n-BuLi and subsequently reacted with tosyl azide, a cycloaddition occurs and results in chloride substitution at a B-Cl vertex. The competing and dominant pathway is a substitution reaction to form the azide N3CB11Cl11(-). This rare anionic carboranyl azide reacts with PPh3 in FC6H5 to afford a stable anionic phosphazide. When dissolved in tetrahydrofuran, the phosphazide is in equilibrium with free PPh3 and N3CB11Cl11(-). Both the triazole and phosphazide are characterized by single-crystal X-ray diffraction, NMR and IR spectroscopy, and high-resolution mass spectrometry.

The Citrus clementina Putative Allergens: From Proteomic Analysis to Structural Features

Several allergens have been identified and characterized in the genus Citrus, which belongs to the germin-like proteins (GPLs), profilins, and non-specific lipid transfer proteins (nsLTPs). In this work, in silico sequence analysis, protein purification, mass spectrometry identification, and the spectral counting method were integrated to identify new putative allergens of Citrus clementina and their expression level in the fruit peel. The in silico analysis revealed fifteen new sequences belonging to GLPs (Cit cl 1), and two more belonging to nsLTPs (Cit cl 3). No other new sequences were found as regards profilins (Cit cl 2). Each putative allergen from fruit peel was obtained using different protein extraction methods, and the protein sequences of the putative allergens were identified by means of LTQ-Orbitrap XL mass spectrometer. The spectral counting strategy revealed that Cit cl 1 had a higher expression level than Cit cl 2 and Cit cl 3. To predict the quaternary structure and deduced function of Cit cl 1, its primary sequence was used as a template to search a homologous protein structure in the RCSB PDB Database, getting high correspondence with the oxalate oxidase protein in barley.

Reductive degradation of chlorinated organic pollutants-contaminated water by bimetallic Pd/Al nanoparticles: Effect of acidic condition and surfactants

The Pd/Al nanoparticles (NPs) prepared by aqueous cementation were employed to probe hydrodechlorination (HDC) efficiencies of 4-chlorophenol (4-CP) in aqueous solution and 2-chlorobiphenyl (2-PCB) in surfactant solution. Major factors affecting HDC performance were investigated including acidic types, pH conditions, and surfactant types and their concentrations. Among HCl, H2SO4, H3PO4, formic acid, and acetic acid, only HCl was the proper pH adjustor to initiate HDC reaction of 4-CP with Pd/Al NPs at pH 3.0 due to the particular penetration function of active Cl− on the compact oxide film of Al. Aqueous pH states obviously influenced HDC efficiency and its values stable at pH 3–4 were the optimum range for HDC with HCl adjustor. 0.389mM of 4-CP could be almost completely dechlorinated into phenol after 30-min reaction using 2g/L of Pd/Al NPs with 1.2wt.% of Pd loading. In addition, the effect of surfactants on HDC process of highly hydrophobic 2-PCB was explored, which were employed for its better solubilization. The addition of surfactants including SDS, CTAB, Tween 80, or Brij 30 had adverse effect on HDC activity of Pd/Al NPs due to their inhibiting effect on Al corrosion. The adverse effect was closely related with the concentrations of surfactants especially for each CMC level and molecular structures.

An effective triblock copolymer as a suppressor for microvia filling via copper electrodeposition

In this work, an effective suppressor was found in copper electroplating solution for microvia filling. The suppressor is a triblock copolymer comprised of ethylene oxide (EO)–propylene oxide (PO)–ethylene oxide (EO) with a molecular weight of 2900 (EPE 2900). In terms of the obtained filling performance evaluated by observing the obtained cross-sectional views of the microvias after electroplating, the electroplating solution was systematically studied as functions of Cl− concentration, EPE 2900 concentration, and convection conditions. It was found that filling performance was greatly dependent on these key factors. In the developed copper electroplating formulation, EPE 2900 was able to yield sufficient filling performance in a broad Cl− concentration ranging from 3 to 200ppm, although the optimized value was determined to be about 30ppm in terms of the best filling performance. During the microvia filling process, Cl− concentration, EPE 2900 concentration, and forced convection would affect each other. Their interactions were studied based on the anchor effect of Cl− on the adsorption of EPE 2900 on Cu substrates. In doing so, extensive electrochemical experiments including galvanostatic measurements, linear sweep voltammetry, electrochemical impedance spectroscopy and cyclic voltammetry were employed to study the adsorption behavior of EPE 2900 on the cathode during both the copper electrodeposition and dissolution processes. An adsorbing mechanism of EPE 2900 on cathode was proposed to elucidate the promotional role in improving the microvia filling performance.

Synthesis and Hydrolysis–Condensation Study of Water-Soluble Self-Assembled Pentacoordinate Polysilylamides

Polysilylamides (n = 1–8) with a Si–Cl functionality containing pentacoordinate silicon in the backbone were produced in high yield by transsilylation of bis(chloromethyl)methylchlorosilane and the trimethylsilyl derivative of diketopiperazine. Pentacoordinate polysilylamides were highly soluble in water as a result of silicon water coordination (Si←OH2) from hydrolysis of the Si–Cl group in each repeat unit. Interestingly, the water silicon coordination in polysilanolamides was stable toward self-condensation and found to contain pentacoordinate silicon even in water, thus avoiding siloxane (Si–O–Si) bond formation. In the gas phase the polysilanolamides underwent intramolecular stepwise hydrolysis–condensation possibly as a result of C═C double-bond formation at each monomer unit, as observed by MALDI-TOF MS. Low-intensity peaks of macrocyclic polysilanolamides (n = 2–5) were also observed that contain water molecules. For a better understanding of the hydrolysis–condensation process of the polysilylamide, new model compounds of pentacoordinated silicon derivatives of pyridones were synthesized, characterized, and compared with the polysilanolamides using NMR and X-ray crystallography. X-ray analysis of the model compounds revealed insight into the silicon water coordination in each repeat unit and the mode of packing within the polymers that contain these monomer units. It is found that the partial hydrolysis of the model pentacoordinate chlorosilanes gives water-coordinated pentacoordinate silicon species that resemble an intermediate in the aqueous hydrolysis of pentacoordinate polysilylamides.

Effect of progesterone concentration and duration of proestrus on fertility in beef cattle after fixed-time artificial insemination

The objective was to determine the effect of plasma progesterone concentration and the duration of proestrus during growth of the ovulatory follicle on fertility in beef cattle. Heifers (N = 61) and postpartum cows (N = 79) were assigned randomly to four groups in a two-by-two design involving luteal-phase versus subluteal-phase plasma progesterone concentrations and normal versus short proestrus. To synchronize follicular wave emergence, estradiol-17β was given im during the midluteal phase (Day 0) and concurrently, a once-used controlled intravaginal progesterone-releasing device was placed intravaginally. In the subluteal-phase progesterone groups, a luteolytic dose of PGF2α was given on Day 0 and again 12 hours later. In the luteal-phase progesterone groups, PGF2α was not given (so as to retain a functional CL). The controlled intravaginal progesterone-releasing device was removed and PGF2α was given on Days 7 or 8 in the normal- and short-proestrus groups, respectively. Cattle were given lutropin im 12 or 36 hours later in the short- and normal-proestrus groups, respectively, with AI at 12 hours after lutropin treatment. Transrectal ultrasonography was used to monitor ovarian response during treatments and to diagnose pregnancy 60 days after AI. Cattle (heifers and cows combined) in the subluteal-phase progesterone groups and normal proestrus groups had a larger follicle at the time of AI, and a larger CL that secreted more progesterone 9 days after AI than cattle with luteal-phase progesterone concentrations or those with short proestrus (P < 0.03). There was a higher incidence of ovulation (P < 0.01) the day after AI in heifers (55/61; 90%) than in cows (44/79; 56%). Pregnancy rates ranged from 11% to 54%, and were higher in cattle (heifers and cows combined) in the subluteal-phase progesterone groups and normal proestrus groups than in the luteal-phase progesterone or short proestrus groups, respectively, (P < 0.02). In conclusion, a short proestrous interval reduced pregnancy rate after fixed-time AI in beef cattle. A low progesterone environment during growth of the ovulatory follicle increased the preovulatory follicle size and subsequent CL size and function, and compensated for the effect of a short proestrus on pregnancy rates.

Cis-Dichlorido(dimethyl sulfoxide-κS)(N,N,N′,N′-tetramethylguanidine-κN′′)platinum(II)

In the title compound, cis-[PtCl2(C5H13N3)(C2H6OS)], the four-coordinate PtII atom is bonded to one N atom of the N,N,N′,N′-tetra­methyl­guanidine ligand, one dimethyl sulfoxide S atom and two chloride ligands, forming a cis-square-planar geometry. The bond lengths and angles of the N—Pt—Cl functionality are typical for imine dichloridoplatinum(II) complexes. The H atom of the imino group is oriented towards the O atom of the sulfoxide group of a neighboring mol­ecule and forms an N—H⋯O hydrogen bond.

Trigeminal Ganglion Neurons of Mice Show Intracellular Chloride Accumulation and Chloride-Dependent Amplification of Capsaicin-Induced Responses

Intracellular Cl− concentrations ([Cl−]i) of sensory neurons regulate signal transmission and signal amplification. In dorsal root ganglion (DRG) and olfactory sensory neurons (OSNs), Cl− is accumulated by the Na+-K+-2Cl− cotransporter 1 (NKCC1), resulting in a [Cl−]i above electrochemical equilibrium and a depolarizing Cl− efflux upon Cl− channel opening. Here, we investigate the [Cl−]i and function of Cl− in primary sensory neurons of trigeminal ganglia (TG) of wild type (WT) and NKCC1−/− mice using pharmacological and imaging approaches, patch-clamping, as well as behavioral testing. The [Cl−]i of WT TG neurons indicated active NKCC1-dependent Cl− accumulation. Gamma-aminobutyric acid (GABA)A receptor activation induced a reduction of [Cl−]i as well as Ca2+ transients in a corresponding fraction of TG neurons. Ca2+ transients were sensitive to inhibition of NKCC1 and voltage-gated Ca2+ channels (VGCCs). Ca2+ responses induced by capsaicin, a prototypical stimulus of transient receptor potential vanilloid subfamily member-1 (TRPV1) were diminished in NKCC1−/− TG neurons, but elevated under conditions of a lowered [Cl−]o suggesting a Cl−-dependent amplification of capsaicin-induced responses. Using next generation sequencing (NGS), we found expression of different Ca2+-activated Cl− channels (CaCCs) in TGs of mice. Pharmacological inhibition of CaCCs reduced the amplitude of capsaicin-induced responses of TG neurons in Ca2+ imaging and electrophysiological recordings. In a behavioral paradigm, NKCC1−/− mice showed less avoidance of the aversive stimulus capsaicin. In summary, our results strongly argue for a Ca2+-activated Cl−-dependent signal amplification mechanism in TG neurons that requires intracellular Cl− accumulation by NKCC1 and the activation of CaCCs.

The 2,2′-diindolylmethane dianion supporting scaffold for group 15 compounds

Deprotonated 2,2′-diindolylmethane functions as a dianionic chelating ligand for the isolation and characterization of the group 15 species {ArCH(3-MeC8H4N)2}PCl (2) and {ArCH(3-MeC8H4N)2}SbNMe2 (6, Ar=p-C6H4Br). The single crystal X-ray structure of 2 revealed a six-membered heterocycle featuring an N–P–N bonding motif and a terminal P–Cl function. The antimony complex 6 is a rare example of an N-heterocyclic aminostibine. DFT computations were used to examine the energies of isomers for these compounds and to describe the bonding features of the diindolyl fragment with the group 15 cation.