Lipopolysaccharide (LPS)-mediated macrophage activation: the role of calcium in the generation of tumoricidal activity

International Nuclear Information System (INIS)

Drysdale, B.E.; Shin, H.S.

1986-01-01

As the authors reported, calcium ionophore, A23187, activates macrophages (M theta) for tumor cell killing and the activated M theta produce a soluble cytotoxic factor (M theta-CF) that is similar if not identical to tumor necrosis factor. Based on these observations they have investigated whether calcium is involved in the activation mediated by another potent M theta activator, LPS. The authors have shown that A23187 caused uptake of extracellular 45 Ca ++ but LPS did not. They have examined the effect of depleting extracellular calcium by using medium containing no added calcium containing 1.0 mM EGTA. In no case did depletion result in decreased M theta-CF production by the M theta activated with LPS. Measurements using the fluorescent, intracellular calcium indicator, Quin 2 have also been performed. While ionomycin, caused a rapid change in the Quin-2 signal, LPS at a concentration even in excess of that required to activate the M theta caused no change in the signal. When high doses of Quin 2 or another intracellular chelator, 8-(diethylaminol-octyl-3,4,5-trimethoxybenzoate, were used to treat M theta, M theta-CF production decreased and cytotoxic activity was impaired. These data indicate that one or more of the processes involved in M theta-CF production does require calcium, but that activation mediated by LPS occurs without the influx of extracellular calcium or redistribution of intracellular calcium

Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

Science.gov (United States)

Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

1987-01-01

Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

Abiotic degradation of antibiotic ionophores

DEFF Research Database (Denmark)

Bohn, Pernille; Bak, Søren A; Björklund, Erland

2013-01-01

Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C f...... because they absorb light of environmentally irrelevant wavelengths....

Polyether ionophores-promising bioactive molecules for cancer therapy.

Science.gov (United States)

Huczyński, Adam

2012-12-01

The natural polyether ionophore antibiotics might be important chemotherapeutic agents for the treatment of cancer. In this article, the pharmacology and anticancer activity of the polyether ionophores undergoing pre-clinical evaluation are reviewed. Most of polyether ionophores have shown potent activity against the proliferation of various cancer cells, including those that display multidrug resistance (MDR) and cancer stem cells (CSC). The mechanism underlying the anticancer activity of ionophore agents can be related to their ability to form complexes with metal cations and transport them across cellular and subcellular membranes. Increasing evidence shows that the anticancer activity of polyether ionophores may be a consequence of the induction of apoptosis leading to apoptotic cell death, arresting cell cycle progression, induction of the cell oxidative stress, loss of mitochondrial membrane potential, reversion of MDR, synergistic anticancer effect with other anticancer drugs, etc. Continued investigation of the mechanisms of action and development of new polyether ionophores and their derivatives may provide more effective therapeutic drugs for cancer treatments. Copyright © 2012 Elsevier Ltd. All rights reserved.

Salinomycin, A Polyether Ionophoric Antibiotic, Inhibits Adipogenesis

Science.gov (United States)

Szkudlarek-Mikho, Maria; Saunders, Rudel A.; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

2012-01-01

The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor γ. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy. PMID:23123626

Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis

International Nuclear Information System (INIS)

Szkudlarek-Mikho, Maria; Saunders, Rudel A.; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

2012-01-01

Highlights: ► Salinomycin inhibits preadipocyte differentiation into adipocytes. ► Salinomycin inhibits transcriptional regulation of adipogenesis. ► Pharmacological effects of salinomycin suggest toxicity in cancer therapy. -- Abstract: The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor γ. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis

Energy Technology Data Exchange (ETDEWEB)

Szkudlarek-Mikho, Maria; Saunders, Rudel A. [Department of Medicine, Biochemistry and Cancer Biology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH 43614 (United States); Yap, Sook Fan [Faculty of Medicine and Health Sciences, Department of Pre-Clinical Sciences, University of Tunku Abdul Rahman (Malaysia); Ngeow, Yun Fong [Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chin, Khew-Voon, E-mail: khew-voon.chin@utoledo.edu [Department of Medicine, Biochemistry and Cancer Biology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH 43614 (United States)

2012-11-30

Highlights: Black-Right-Pointing-Pointer Salinomycin inhibits preadipocyte differentiation into adipocytes. Black-Right-Pointing-Pointer Salinomycin inhibits transcriptional regulation of adipogenesis. Black-Right-Pointing-Pointer Pharmacological effects of salinomycin suggest toxicity in cancer therapy. -- Abstract: The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor {gamma}. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

Development of a disposable mercury ion-selective optode based on tritylpicolinamide as ionophore

NARCIS (Netherlands)

Kuswandi, Bambang; Nuriman, [Unknown; Dam, H.H.; Reinhoudt, David; Verboom, Willem

2007-01-01

A disposable ion-selective optode for mercury based on trityl-picolinamide (T-Pico) as neutral ionophore was developed. The sensing layer consist of plasticised PVC incorporating T-Pico as a selective ionophore for Hg2+, ETH 5418 as a chromoionophore, and potassium

New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

International Nuclear Information System (INIS)

Khamjumphol, Utisawadee; Watchasit, Sarayut; Suksai, Chomchai; Janrungroatsakul, Wanwisa; Boonchiangma, Suthasinee; Tuntulani, Thawatchai; Ngeontae, Wittaya

2011-01-01

Highlights: → New four ionophores having tripodal amine (TPA) unit on anthracene and calixarene. → Synthesis and characterization data were reported. → Incorporated to the plasticized PVC membranes to prepare Cd-ISEs. → Two TPA units on calixarene showed the best selectivity toward Cd 2+ . → Applied for sensing Cd 2+ from the oxidation of CdS QDs solution. - Abstract: Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd 2+ was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship between structures of ionophores and membrane characteristics were explored. The ionophore IV which composed of two opposites TPA units on the calix[4]arene compartment showed the best selectivity toward Cd 2+ . The best membrane electrode was fabricated from ionophore IV (10.2 mmol kg -1 ) with KTpClPB (50.1 mol% related to the ionophore) as an ion exchanger incorporated in the DOS plasticized PVC membrane (1:2; PVC:DOS). The Cd-ISE fabricated from ionophore IV exhibited good properties with a Nernstian response of 29.4 ± 0.6 mV decade -1 of activity for Cd 2+ ions and a working concentration range of 1.6 x 10 -6 -1.0 x 10 -2 M. The sensor has a fast response time of 10 s and can be used for at least 1 week without any divergence in potential. The electrode can be used in the pH range of 6.0-9.0. The proposed electrodes using ionophores III and IV were employed as a probe for determining Cd 2+ from the oxidation of CdS QDs

New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

Energy Technology Data Exchange (ETDEWEB)

Khamjumphol, Utisawadee [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Watchasit, Sarayut [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Suksai, Chomchai [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Burapha University, Chonburi 20131 (Thailand); Janrungroatsakul, Wanwisa [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Boonchiangma, Suthasinee [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Tuntulani, Thawatchai [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Ngeontae, Wittaya, E-mail: wittayange@kku.ac.th [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen 40002 (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management, Khon Kaen University, Khon Kaen 40002 (Thailand)

2011-10-17

Highlights: {yields} New four ionophores having tripodal amine (TPA) unit on anthracene and calixarene. {yields} Synthesis and characterization data were reported. {yields} Incorporated to the plasticized PVC membranes to prepare Cd-ISEs. {yields} Two TPA units on calixarene showed the best selectivity toward Cd{sup 2+}. {yields} Applied for sensing Cd{sup 2+} from the oxidation of CdS QDs solution. - Abstract: Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd{sup 2+} was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship between structures of ionophores and membrane characteristics were explored. The ionophore IV which composed of two opposites TPA units on the calix[4]arene compartment showed the best selectivity toward Cd{sup 2+}. The best membrane electrode was fabricated from ionophore IV (10.2 mmol kg{sup -1}) with KTpClPB (50.1 mol% related to the ionophore) as an ion exchanger incorporated in the DOS plasticized PVC membrane (1:2; PVC:DOS). The Cd-ISE fabricated from ionophore IV exhibited good properties with a Nernstian response of 29.4 {+-} 0.6 mV decade{sup -1} of activity for Cd{sup 2+} ions and a working concentration range of 1.6 x 10{sup -6}-1.0 x 10{sup -2} M. The sensor has a fast response time of 10 s and can be used for at least 1 week without any divergence in potential. The electrode can be used in the pH range of 6.0-9.0. The proposed electrodes using ionophores III and IV were employed

Hypertonic Saline Suppresses NADPH Oxidase-Dependent Neutrophil Extracellular Trap Formation and Promotes Apoptosis

Directory of Open Access Journals (Sweden)

Ajantha Nadesalingam

2018-03-01

Full Text Available Tonicity of saline (NaCl is important in regulating cellular functions and homeostasis. Hypertonic saline is administered to treat many inflammatory diseases, including cystic fibrosis. Excess neutrophil extracellular trap (NET formation, or NETosis, is associated with many pathological conditions including chronic inflammation. Despite the known therapeutic benefits of hypertonic saline, its underlying mechanisms are not clearly understood. Therefore, we aimed to elucidate the effects of hypertonic saline in modulating NETosis. For this purpose, we purified human neutrophils and induced NETosis using agonists such as diacylglycerol mimetic phorbol myristate acetate (PMA, Gram-negative bacterial cell wall component lipopolysaccharide (LPS, calcium ionophores (A23187 and ionomycin from Streptomyces conglobatus, and bacteria (Pseudomonas aeruginosa and Staphylococcus aureus. We then analyzed neutrophils and NETs using Sytox green assay, immunostaining of NET components and apoptosis markers, confocal microscopy, and pH sensing reagents. This study found that hypertonic NaCl suppresses nicotinamide adenine dinucleotide phosphate oxidase (NADPH2 or NOX2-dependent NETosis induced by agonists PMA, Escherichia coli LPS (0111:B4 and O128:B12, and P. aeruginosa. Hypertonic saline also suppresses LPS- and PMA- induced reactive oxygen species production. It was determined that supplementing H2O2 reverses the suppressive effect of hypertonic saline on NOX2-dependent NETosis. Many of the aforementioned suppressive effects were observed in the presence of equimolar concentrations of choline chloride and osmolytes (d-mannitol and d-sorbitol. This suggests that the mechanism by which hypertonic saline suppresses NOX2-dependent NETosis is via neutrophil dehydration. Hypertonic NaCl does not significantly alter the intracellular pH of neutrophils. We found that hypertonic NaCl induces apoptosis while suppressing NOX2-dependent NETosis. In contrast, hypertonic

Immobilization of ionophore and surface characterization studies of the titanium(III) ion in a PVC-membrane sensor.

Science.gov (United States)

Rezayi, Majid; Heng, Lee Yook; Kassim, Anuar; Ahmadzadeh, Saeid; Abdollahi, Yadollah; Jahangirian, Hossein

2012-01-01

Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride) (PVC) matrices, and these were examined to determine Ti(III) selectivity. To predict the selectivity of Ti(III), a PVC membrane was used to investigate the binding of Ti(III) to c-methylcalix[4]resorcinarene (CMCR). The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III) at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl) borate (NaTFPB) as a lipophilic ionic additive, and dioctylphthalate (DOP) as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs). The strengths of the ion-ionophore (CMCR-Ti(OH)(OH(2))(5) (2+)) interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and and X-ray diffraction (XRD).

The inflammatory and tumor-promoting sesquiterpene lactone, thapsigargin, activates platelets by selective mobilization of calcium as shown by protein phosphorylations

DEFF Research Database (Denmark)

Thastrup, Ole; Linnebjerg, H; Bjerrum, P J

1987-01-01

We have studied the activation of human blood platelets by the inflammatory and tumor-promoting sesquiterpene lactone, thapsigargin. The effect of thapsigargin was compared with other common agonists (calcium ionophore A23187, phorbol ester TPA and thrombin). Platelet aggregation, serotonin release...

Regulation of the sodium/potassium/chloride cotransporter by calcium and cyclic AMP in cultured vascular smooth muscle cells

International Nuclear Information System (INIS)

Higgins, B.L.; Smith, L.; Smith, J.B.

1987-01-01

The activity of the Na/K/Cl cotransporter in smooth muscle cells cultured from rat aorta was assayed by measuring the initial rate of furosemide-inhibitable 86 Rb influx or efflux. Five uM furosemide or 0.2 uM bumetanide inhibited influx by 50%. Furosemide-inhibitable 86 Rb influx depended on the presence of all 3 ions in the external medium. The dependence on Na and K was hyperbolic with apparent Km values of 45 and 5 mM, respectively. The dependence on Cl was sigmoidal. Assuming a stoichiometry of 1:1:2 for Na:K:Cl, a Km for Cl of 60 mM was obtained from a Hofstee plot of the data. Rapidly growing cells had 3 fold higher cotransport activity than quiescent cells. Angiotensin II (ANG) stimulated furosemide-inhibitable 86 Rb efflux by 2 fold. An ANG receptor antagonist prevented ANG from increasing cotransport activity. Two calcium ionophores, A23187 and ionomycin, increased cotransport activity by 2 fold. Phorbol myristate acetate had no effect on cotransport activity. Isoproterenol, dibutyryl cyclic AMP, cholera toxin, or methylisobutylxanthine inhibited furosemide-sensitive 86 Rb influx by 35 to 50%. From these findings they conclude that increasing cytoplasmic free calcium stimulates cotransport activity, whereas increasing cellular cyclic AMP inhibits the cotransporter

Complex actions of ionomycin in cultured cerebellar astrocytes affecting both calcium-induced calcium release and store-operated calcium entry

DEFF Research Database (Denmark)

Müller, Margit S; Obel, Linea Lykke Frimodt; Waagepetersen, Helle S

2013-01-01

The polyether antibiotic ionomycin is a common research tool employed to raise cytosolic Ca(2+) in almost any cell type. Although initially thought to directly cause physicochemical translocation of extracellular Ca(2+) into the cytosol, a number of studies have demonstrated that the mechanism of......(2+), consisting of an initial peak and a subsequent sustained plateau. The response was dependent on concentration and exposure time. While the plateau phase was abolished in the absence of extracellular Ca(2+), the peak phase persisted. The peak amplitude could be lowered significantly...... by application of dantrolene, demonstrating involvement of Ca(2+)-induced Ca(2+)-release (CICR). The plateau phase was markedly reduced when store-operated Ca(2+)-entry (SOCE) was blocked with 2-aminoethoxydiphenyl borate. Our results show that ionomycin directly affects internal Ca(2+) stores in astrocytes...

Characterization of transport of calcium by microsomal membranes from roots maize

International Nuclear Information System (INIS)

Vaughan, M.A.

1985-01-01

This study investigates calcium transport by membranes of roots of maize isolated by differential centrifugation. The preparation was determined to be enriched in plasma membrane using market enzyme and electron microscopy. Using the 45 Ca filtration technique and liquid scintillation counting, vesicular calcium uptake was shown to be stimulated by added calmodulin and specific for and dependent on ATP. Conditions for maximal calcium accumulation were found to be 30 min incubation in the presence of 5 mM ATP, 5 mM MgCl 2 , 50 μM CaCl 2 , at 23 0 C, and at pH 6.5. Calcium uptake was inhibited by the ionophores A23187, X-537A, and ionomycin. Sodium fluoride, ruthenium red, and p-chloromercuribenzoate completely inhibited transport: diamide and vanadate produced slight inhibition; caffeine, caffeic acid, oligomycin, and ouabain produced little or no inhibition. Chlorpromazine, W7, trifluoperazine, and R 24 571 inhibit calcium uptake irrespective of added calmodulin, while W5 showed little effect on uptake. Verapamil, nifedipine, cinnarizine, flunarizine, lidoflazine, and diltiazem decreased calcium uptake by 17%-50%. Electron microscopic localization of calcium by pyroantimonate showed vesicles incubated with calmodulin and ATP showed the greatest amount of precipitate. These results suggest that these vesicles accumulate calcium in an ATP-dependent, calmodulin-stimulated manner

PKC and Rab13 mediate Ca2+ signal-regulated GLUT4 traffic.

Science.gov (United States)

Deng, Bangli; Zhu, Xiaocui; Zhao, Yihe; Zhang, Da; Pannu, Alisha; Chen, Liming; Niu, Wenyan

2018-01-08

Exercise/muscle contraction increases cell surface glucose transporter 4 (GLUT4), leading to glucose uptake to regulate blood glucose level. Elevating cytosolic Ca 2+ mediates this effect, but the detailed mechanism is not clear yet. We used calcium ionophore ionomycin to raise intracellular cytosolic Ca 2+ level to explore the underlying mechanism. We showed that in L6 myoblast muscle cells stably expressing GLUT4myc, ionomycin increased cell surface GLUT4myc levels and the phosphorylation of AS160, TBC1D1. siPKCα and siPKCθ but not siPKCδ and siPKCε inhibited the ionomycin-increased cell surface GLUT4myc level. siPKCα, siPKCθ inhibited the phosphorylation of AS160 and TBC1D1 induced by ionomycin. siPKCα and siPKCθ prevented ionomycin-inhibited endocytosis of GLUT4myc. siPKCθ, but not siPKCα inhibited ionomycin-stimulated exocytosis of GLUT4myc. siRab13 but not siRab8a, siRab10 and siRab14 inhibited the exocytosis of GLUT4myc promoted by ionomycin. In summary, ionomycin-promoted exocytosis of GLUT4 is partly reversed by siPKCθ, whereas ionomycin-inhibited endocytosis of GLUT4 requires both siPKCα and siPKCθ. PKCα and PKCθ contribute to ionomycin-induced phosphorylation of AS160 and TBC1D1. Rab13 is required for ionomycin-regulated GLUT4 exocytosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of angiotensin II and ionomycin on fluid and bicarbonate absorption in the rat proximal tubule

International Nuclear Information System (INIS)

Chatsudthipong, V.; Chan, Y.L.

1986-01-01

Microperfusion of proximal convoluted tubule(PCT) and peritubular capillaries was performed to examine the effects of angiotensin II(Ang II) and ionomycin on fluid and bicarbonate absorption. Bicarbonate was determined by microcalorimetry and C-14 inulin was used as a volume marker. The rates of bicarbonate absorption (JHCO 3 ) was 143 peq/min x mm and fluid absorption(Jv) was 2.70 nl/min x mm, when PCT and capillary perfusate contained normal Ringer solution. Addition of Ang II (10 -6 M) to the capillary perfusate caused reductions of JHCO 3 and Jv by 35%. A similar effect was observed when ionomycin was added to the capillary perfusate. Ang II antagonist, (Sar 1 , Ile 8 )-Angiotensin II(10 -6 M), completely blocked the inhibitory effect of Ang II on Jv and JHCO 3 . Removal of calcium from both luminal and capillary perfusate did not change the effect of Ang II on Jv and JHCO 3 . Our results indicate that Ang II inhibits the sodium-hydrogen exchanger in the proximal tubule via interacting with angiotensin receptor. The mechanism of Ang II action may involve mobilization of intracellular calcium

SIMULTANEOUS EXPRESSION AND REGULATION OF G-CSF AND IL-6 MESSENGER-RNA IN ADHERENT HUMAN MONOCYTES AND FIBROBLASTS

NARCIS (Netherlands)

VELLENGA, E; VANDERVINNE, B; DEWOLF, JTM; HALIE, MR

The regulation of granulocyte-colony stimulating factor (G-CSF) and interleukin-6 (IL-6) mRNA was studied in human adherent monocytes in response to the protein kinase C activator, oleolyl-acetylglycerol (OAG), the calcium-ionophore A23187 and the cyclic AMP elevating agents, dibutyryl c-AMP

Cordia verbenacea and secretion of mast cells in different animal species.

Science.gov (United States)

de Oliveira, Déborah Mara Costa; Luchini, Ana Carolina; Seito, Leonardo Noboru; Gomes, José Carlos; Crespo-López, María Elena; Di Stasi, Luiz Claudio

2011-05-17

Different plant species from Cordia genera are used in folk medicine as anti-inflammatory medication throughout the tropical and subtropical regions of the world. In Brazil, Cordia verbenacea is a medicinal plant known as "erva-baleeira". The alcoholic extracts, decoctions and infusions with leaves of C. verbenacea are used in Brazilian traditional medicine for treatment of cough, pneumonia, parasitic diseases and, especially, the inflammatory processes. Anti-inflammatory activity was already demonstrated; however, molecular mechanisms of action are not completely understood. Considering the importance of histamine in early events of inflammation and in allergic diseases, we evaluated the effect of ethanol extract of leaves of C. verbenacea on histamine release (in vitro and in vivo studies) from different types of mast cells induced by chemical agents using several species of rodents. The extraction and quantification of histamine were performed by using an automatic fluorometric continuous flow system. The extract of C. verbenacea (30 μg/ml) reduced the in vitro secretion of histamine from rat mast cells induced by ionophore A23187, concanavalin A and compound 48/80, respectively, to 22.1 ± 2.2%, 24.3 ± 2.5% and 21.4 ± 2.1%. At the same concentration, the extract also inhibited the secretion of histamine from mast cells of guinea pig induced by ionophore A23187 to 33.3 ± 2.2%, and mast cells of hamster induced by ionophore A23187 and concanavalin A to 15.8 ± 2.5% and 10.8 ± 2.6%, respectively. The oral treatment with the extract (300 mg/kg) also inhibited the secretion of histamine induced by A23187 about to 36.3 ± 3.2% in rats. C. verbenacea inhibits the in vitro secretion of histamine from mast cells of different animal species, as well as the secretion of mast cells from animals treated with the extract, which gives not only the proven anti-inflammatory effect of the plant, but also anti-allergic effect, opening new possibilities for future anti

Effect of methylmercury on histamine release from rat mast cells

Energy Technology Data Exchange (ETDEWEB)

Graevskaya, Elizabeth E.; Rubin, Andrew B. [Moscow State University, Biological Faculty, Department of Biophysics, 119899, Vorobjovy Gory, Moscow (Russian Federation); Yasutake, Akira; Aramaki, Ryoji [National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008 (Japan)

2003-01-01

Methylmercury chloride (MeHgCl) is well known as a significant environmental hazard, particularly as a modulator of the immune system. As it is acknowledged that the critical effector cells in the host response participating in various biological responses are mast cells, we tried to define the possible contribution of mast cells in the development of methylmercury-evoked effects. We investigated the effects of methylmercury on the rat mast cell degranulation induced by non-immunological stimuli (the selective liberator of histamine, compound 48/80, and calcium ionophore A23187) both in vivo and in vitro. Using the cells prepared from methylmercury-intoxicated rats through a 5-day treatment of MeHgCl (10 mg/kg/day), we observed the suppression of calcium ionophore A23187- and 48/80-induced histamine release, which was enhanced with time after treatment. Similar suppression was observed in the ionophore-stimulated release, when cells were prepared from rat with a single treatment of MeHgCl (20 mg/kg). It should be noted that when cells from the control rat were pre-incubated with methylmercury in vitro at a 10{sup -8} M concentration for 10 min, A23187 and compound 48/80-stimulated histamine release was significantly enhanced. However, when the pre-incubation period was prolonged to 30 min, the release was suppressed. An increase in the methylmercury concentration to 10{sup -6} M also suppressed the histamine release. These results show that methylmercury treatment can modify mast cell function depending on concentration and time, and might provide an insight into the role of mast cells in the development of methylmercury-stimulated effects. (orig.)

Genome-wide immunity studies in the rabbit: transcriptome variations in peripheral blood mononuclear cells after in vitro stimulation by LPS or PMA-Ionomycin.

Science.gov (United States)

Jacquier, Vincent; Estellé, Jordi; Schmaltz-Panneau, Barbara; Lecardonnel, Jérôme; Moroldo, Marco; Lemonnier, Gaëtan; Turner-Maier, Jason; Duranthon, Véronique; Oswald, Isabelle P; Gidenne, Thierry; Rogel-Gaillard, Claire

2015-01-23

Our purpose was to obtain genome-wide expression data for the rabbit species on the responses of peripheral blood mononuclear cells (PBMCs) after in vitro stimulation by lipopolysaccharide (LPS) or phorbol myristate acetate (PMA) and ionomycin. This transcriptome profiling was carried out using microarrays enriched with immunity-related genes, and annotated with the most recent data available for the rabbit genome. The LPS affected 15 to 20 times fewer genes than PMA-Ionomycin after both 4 hours (T4) and 24 hours (T24), of in vitro stimulation, in comparison with mock-stimulated PBMCs. LPS induced an inflammatory response as shown by a significant up-regulation of IL12A and CXCL11 at T4, followed by an increased transcription of IL6, IL1B, IL1A, IL36, IL37, TNF, and CCL4 at T24. Surprisingly, we could not find an up-regulation of IL8 either at T4 or at T24, and detected a down-regulation of DEFB1 and BPI at T24. A concerted up-regulation of SAA1, S100A12 and F3 was found upon stimulation by LPS. PMA-Ionomycin induced a very early expression of Th1, Th2, Treg, and Th17 responses by PBMCs at T4. The Th1 response increased at T24 as shown by the increase of the transcription of IFNG and by contrast to other cytokines which significantly decreased from T4 to T24 (IL2, IL4, IL10, IL13, IL17A, CD69) by comparison to mock-stimulation. The granulocyte-macrophage colony-stimulating factor (CSF2) was by far the most over-expressed gene at both T4 and T24 by comparison to mock-stimulated cells, confirming a major impact of PMA-Ionomycin on cell growth and proliferation. A significant down-regulation of IL16 was observed at T4 and T24, in agreement with a role of IL16 in PBMC apoptosis. We report new data on the responses of PBMCs to LPS and PMA-Ionomycin in the rabbit species, thus enlarging the set of mammalian species for which such reports exist. The availability of the rabbit genome assembly together with high throughput genomic tools should pave the way for more

Anti-Allergic Activity of a Platycodon Root Ethanol Extract

Directory of Open Access Journals (Sweden)

Dong-Yeul Kwon

2010-07-01

Full Text Available Platycodon grandiflorum (Campanulaceae is used as traditional medicine in Asian countries. In Korean traditional medicine, Platycodon root has been widely used since ancient times as a traditional drug to treat cold, cough and asthma. However, its effects on bone marrow-derived mast cell (BMMC-mediated allergy and inflammation mechanisms remain unknown. In this study, the biological effect of Platycodon root ethanol extract (PE was evaluated in BMMC after induction of allergic mediators by phorbol 12-myristate 13-acetate (PMA plus calcium ionophore A23187 (A23187 stimulation. The effect of PE on the production of several allergic mediators, such as interleukin-6 (IL-6, prostaglandin D2 (PGD2, leukotriene C4 (LTC4, β-Hexosaminidase (β-Hex and cyclooxygenase-2 (COX-2 protein, was investigated. The results demonstrate that PE inhibits PMA + A23187 induced production of IL-6, PGD2, LTC4, β-Hexosaminidase and COX-2 protein. Taken together, these results indicate that PE has the potential for use in the treatment of allergy.

A voltammetric method for Fe(iii) in blood serum using a screen-printed electrode modified with a Schiff base ionophore.

Science.gov (United States)

Mittal, Susheel K; Rana, Sonia; Kaur, Navneet; Banks, Craig E

2018-05-23

Herein, a potent electrochemical ionophore (SMS-2) based on a Schiff base has been used for the modification of a screen-printed electrode (SPE). The modified disposable electrode can selectively detect ferric ions in an aqueous medium. Redox behavior of the proposed strip was characterized using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Incorporation of the ligand in the ink of the SPE enhanced the analytical performance of the electrode, and its surface modification was confirmed by SEM and EDX analysis. Shifting/quenching of the cathodic peak potential of the ionophore after binding with Fe(iii) ions was used to detect and measure the ferric ion concentration. This sensor can identify Fe(iii) in the detection range from 0.625 μM to 7.5 μM. The modified SPE can selectively detect ferric ions in the presence of many other interfering ions and has been successfully used to determine the Fe(iii) content in blood serum samples. The metal-ionophore complex structure was optimized using DFT calculations to study the energetics of the metal-ionophore interactions.

Copper as a target for prostate cancer therapeutics: copper-ionophore pharmacology and altering systemic copper distribution

Science.gov (United States)

Denoyer, Delphine; Pearson, Helen B.; Clatworthy, Sharnel A.S.; Smith, Zoe M.; Francis, Paul S.; Llanos, Roxana M.; Volitakis, Irene; Phillips, Wayne A.; Meggyesy, Peter M.; Masaldan, Shashank; Cater, Michael A.

2016-01-01

Copper-ionophores that elevate intracellular bioavailable copper display significant therapeutic utility against prostate cancer cells in vitro and in TRAMP (Transgenic Adenocarcinoma of Mouse Prostate) mice. However, the pharmacological basis for their anticancer activity remains unclear, despite impending clinical trails. Herein we show that intracellular copper levels in prostate cancer, evaluated in vitro and across disease progression in TRAMP mice, were not correlative with copper-ionophore activity and mirrored the normal levels observed in patient prostatectomy tissues (Gleason Score 7 & 9). TRAMP adenocarcinoma cells harbored markedly elevated oxidative stress and diminished glutathione (GSH)-mediated antioxidant capacity, which together conferred selective sensitivity to prooxidant ionophoric copper. Copper-ionophore treatments [CuII(gtsm), disulfiram & clioquinol] generated toxic levels of reactive oxygen species (ROS) in TRAMP adenocarcinoma cells, but not in normal mouse prostate epithelial cells (PrECs). Our results provide a basis for the pharmacological activity of copper-ionophores and suggest they are amendable for treatment of patients with prostate cancer. Additionally, recent in vitro and mouse xenograft studies have suggested an increased copper requirement by prostate cancer cells. We demonstrated that prostate adenocarcinoma development in TRAMP mice requires a functional supply of copper and is significantly impeded by altered systemic copper distribution. The presence of a mutant copper-transporting Atp7b protein (tx mutation: A4066G/Met1356Val) in TRAMP mice changed copper-integration into serum and caused a remarkable reduction in prostate cancer burden (64% reduction) and disease severity (grade), abrogating adenocarcinoma development. Implications for current clinical trials are discussed. PMID:27175597

Muscle-derived interleukin-6: lipolytic, anti-inflammatory and immune regulatory effects

DEFF Research Database (Denmark)

Pedersen, Bente Klarlund; Steensberg, Adam; Keller, Pernille

2003-01-01

is low. Furthermore, cultured human primary muscle cells can increase IL-6 mRNA when incubated with the calcium ionophore ionomycin and it is likely that myocytes produce IL-6 in response to muscle contraction. The biological roles of muscle-derived IL-6 have been investigated in studies in which human...

The effect of tartrazine on histamine release from rat peritoneal mast cells.

Science.gov (United States)

Safford, R J; Goodwin, B F

1984-01-01

The release of histamine from purified rat peritoneal mast cells induced by specific antigen (egg albumin), compound 48/80 and calcium ionophore A23187 was modified by tartrazine. Histamine release induced by 48/80 and antigen was inhibited by the presence of 10(-5) to 10(-2)M tartrazine. The inhibitory effect on egg albumin induced histamine release was maximal when the tartrazine was added simultaneously with egg albumin, and was reduced by increased preincubation of the cells with tartrazine. Tartrazine had a small inhibitory effect on ionophore induced release at high concentrations, but augmented histamine release at tartrazine concentrations of 10(-3) and 10(-4)M. Augmentation of ionophore induced release was maximal at between 0-5 min preincubation of the cells with tartrazine.

Effect of iodide on glucose oxidation and 32P incorporation into phospholipids stimulated by different agents in dog thyroid slices

International Nuclear Information System (INIS)

Tseng, F.Y.; Rani, C.S.; Field, J.B.

1989-01-01

Since iodide (I-) inhibits TSH stimulation of cAMP formation, which mediates most of the effects of the hormone, it has been assumed that this accounts for the inhibitory action of iodide on the thyroid. However, TSH stimulation of 32P incorporation into phospholipids and stimulation of thyroid metabolism by other agonists, such as carbachol, phorbol esters, and ionophore A23187, is not cAMP mediated. The present studies examined the effect of iodide on stimulation of glucose oxidation and 32P incorporation into phospholipids by TSH and other agonists to determine if the inhibition of cAMP formation was responsible for the action of iodide. Preincubation of dog thyroid slices for 1 h with iodide (10(-4) M) inhibited TSH-, (Bu)2cAMP-, carbachol-, methylene blue-, 12-O-tetradecanoyl phorbol-13-acetate-, ionophore A23187-, prostaglandin E1-, and cholera toxin-stimulated glucose oxidation. I- also inhibited the stimulation by TSH, 12-O-tetradecanoyl phorbol-13-acetate, carbachol, and ionophore A23187 of 32P incorporation into phospholipids. The inhibition was similar whether iodide was added 2 h before or simultaneously with the agonist. I- itself sometimes stimulated basal glucose oxidation, but had no effect on basal 32P incorporation into phospholipids. The effects of iodide on basal and agonist-stimulated thyroid metabolism were blocked by methimazole (10(-3) M). When dog thyroid slices were preloaded with 32PO4 or [1-14C]glucose, the iodide inhibition of agonist stimulation disappeared, suggesting that the effect of iodide involves the transport process. In conclusion, I- inhibited stimulation of glucose oxidation and 32P incorporation into phospholipids by all agonists, indicating that the effect is independent of the cAMP system and that iodide autoregulation does not only involve this system. Oxidation and organification of iodide are necessary for the inhibition

Magnesium ionophore II as an extraction agent for trivalent europium and americium

Energy Technology Data Exchange (ETDEWEB)

Makrlik, Emanuel [Czech Univ. of Life Sciences, Prague (Czech Republic). Faculty of Environmental Sciences; Vanura, Petr [Univ. of Chemistry and Technology, Prague (Czech Republic). Dept. of Analytical Chemistry

2016-11-01

Solvent extraction of microamounts of trivalent europium and americium into nitrobenzene by using a mixture of hydrogen dicarbollylcobaltate (H{sup +}B{sup -}) and magnesium ionophore II (L) was studied. The equilibrium data were explained assuming that the species HL{sup +}, HL{sup +}{sub 2}, ML{sup 3+}{sub 2}, and ML{sup 3+}{sub 3} (M{sup 3+} = Eu{sup 3+}, Am{sup 3+}; L=magnesium, ionophore II) are extracted into the nitrobenzene phase. Extraction and stability constants of the cationic complex species in nitrobenzene saturated with water were determined and discussed. From the experimental results it is evident that this effective magnesium ionophore II receptor for the Eu{sup 3+} and Am{sup 3+} cations could be considered as a potential extraction agent for nuclear waste treatment.

Synthesis selective transport properties of cleft-type ionophores having two convergent hydroxamic acid functions

International Nuclear Information System (INIS)

Kim, Duck Hee; Choi, Mi Jung; Chang, Suk Kyu

2001-01-01

A series of cleft-type ionophores having two convergent hydroxamic acid functions are prepared and their selective ionophoric properties toward heavy metal and transition metal ions have been investigated. Hydroxamic acids 3 exhibited a prominent selectivity toward heavy metal ions of Hg 2+ and Pb 2+ , and transition metal ions of Cu 2+ over other transition metal and alkaline earth metal ions from slightly acidic source phase (pH 6) to an acidic receiving phase (pH 1). Selective ionophoric properties toward Pb 2+ and Cu 2+ ions over other surveyed metal ions are also confirmed by the FAB-MS measurements

Polyurethane Ionophore-Based Thin Layer Membranes for Voltammetric Ion Activity Sensing.

Science.gov (United States)

Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

2016-06-07

We report on a plasticized polyurethane ionophore-based thin film material (of hundreds of nanometer thickness) for simultaneous voltammetric multianalyte ion activity detection triggered by the oxidation/reduction of an underlying poly(3-octylthiophene) film. This material provides excellent mechanical, physical, and chemical robustness compared to other polymers. Polyurethane films did not exhibit leaching of lipophilic additives after rinsing with a direct water jet and exhibited resistance to detachment from the underlying electrode surface, resulting in a voltammetric current response with less than acrylate) ionophore-based membranes of the same thickness and composition exhibited a significant deterioration of the signal after identical treatment. While previously reported works emphasized fundamental advancement of multi-ion detection with multi-ionophore-based thin films, polyurethane thin membranes allow one to achieve real world measurements without sacrificing analytical performance. Indeed, polyurethane membranes are demonstrated to be useful for the simultaneous determination of potassium and lithium in undiluted human serum and blood with attractive precision.

Theoretical and Experimental Investigation of Pyridyl thiourea Derivatives As Ionophores For Cu(II) Ion Detection

International Nuclear Information System (INIS)

Wan Mohd Khairul; Mohd Faizuddin Abu Hasan; Adibah Izzati Daud; Adibah Izzati Daud; Hafiza Mohamed Zuki; Ku Halim Ku Bulat; Maisara Abdul Kadir

2016-01-01

Copper (II) ion chemical sensors based on pyridine-thiourea derivatives; N-pyridyl-N ' -(biphenyl-4-carbonyl)thiourea (L1), and N-pyridyl-N ' -(3,5-dimethy oxybenzoyl)thiourea (L2) were synthesised, characterised, and studied as ionophores in the form of thin-films PVC membranes. The ionophores exhibited good responses towards copper (II) ion over the concentration range of 2 x 10 -4 to 10 x 10 -4 M with a limit of detection 1.34 x 10 -5 to 1.48 x 10 -5 M. The proposed sensors L1 and L2 revealed good performance in term of reproducibility and regeneration of the ionophores with low relative standard deviation (RSD) values 4.17 % and 2.74 % respectively. Besides, quantum chemical calculation performed using Gaussian 09 program indicated the oxygen (O) atom from carbonyl moiety (C=O) was the most favourite reactive site and mainly responsible for ionophore Cu(II) interaction. The obtained data revealed pyridine-thiourea derivatives offered great potential as ionophore for the detection of Cu (II) ion. (author)

Genetic screening strategy for rapid access to polyether ionophore producers and products in actinomycetes.

Science.gov (United States)

Wang, Hao; Liu, Ning; Xi, Lijun; Rong, Xiaoying; Ruan, Jisheng; Huang, Ying

2011-05-01

Polyether ionophores are a unique class of polyketides with broad-spectrum activity and outstanding potency for the control of drug-resistant bacteria and parasites, and they are produced exclusively by actinomycetes. A special epoxidase gene encoding a critical tailoring enzyme involved in the biosynthesis of these compounds has been found in all five of the complete gene clusters of polyether ionophores published so far. To detect potential producer strains of these antibiotics, a pair of degenerate primers was designed according to the conserved regions of the five known polyether epoxidases. A total of 44 putative polyether epoxidase gene-positive strains were obtained by the PCR-based screening of 1,068 actinomycetes isolated from eight different habitats and 236 reference strains encompassing eight major families of Actinomycetales. The isolates spanned a wide taxonomic diversity based on 16S rRNA gene analysis, and actinomycetes isolated from acidic soils seemed to be a promising source of polyether ionophores. Four genera were detected to contain putative polyether epoxidases, including Micromonospora, which has not previously been reported to produce polyether ionophores. The designed primers also detected putative epoxidase genes from diverse known producer strains that produce polyether ionophores unrelated to the five published gene clusters. Moreover, phylogenetic and chemical analyses showed a strong correlation between the sequence of polyether epoxidases and the structure of encoded polyethers. Thirteen positive isolates were proven to be polyether ionophore producers as expected, and two new analogues were found. These results demonstrate the feasibility of using this epoxidase gene screening strategy to aid the rapid identification of known products and the discovery of unknown polyethers in actinomycetes.

Platinum porphyrins as ionophores in polymeric membrane electrodes

DEFF Research Database (Denmark)

Lvova, Larisa; Verrelli, Giorgio; Nardis, Sara

2011-01-01

A comparative study of Pt(II)- and Pt(IV)-porphyrins as novel ionophores for anion-selective polymeric membrane electrodes is performed. Polymeric membranes of different compositions, prepared by varying plasticizers, cationic and anionic additives and Pt porphyrins, have been examined...... within the electrode membranes, while those based on Pt(IV)TPPCl2 operate via a mixed mode carrier mechanism, evidencing also a partial reduction of the starting ionophore to Pt(II)TPP. Spectrophotometric measurements of thin polymeric films indicate that no spontaneous formation of hydroxide ion bridged...... porphyrin dimers occurs in the membrane plasticized both with high or low dielectric constant plasticizer, due to a low oxophilicity of central Pt. The computational study of various anion–Pt(IV)TPPCl2 complex formation by means of semi-empirical and density functional theory (DFT) methods revealed a good...

Chloroquine is a zinc ionophore.

Directory of Open Access Journals (Sweden)

Jing Xue

Full Text Available Chloroquine is an established antimalarial agent that has been recently tested in clinical trials for its anticancer activity. The favorable effect of chloroquine appears to be due to its ability to sensitize cancerous cells to chemotherapy, radiation therapy, and induce apoptosis. The present study investigated the interaction of zinc ions with chloroquine in a human ovarian cancer cell line (A2780. Chloroquine enhanced zinc uptake by A2780 cells in a concentration-dependent manner, as assayed using a fluorescent zinc probe. This enhancement was attenuated by TPEN, a high affinity metal-binding compound, indicating the specificity of the zinc uptake. Furthermore, addition of copper or iron ions had no effect on chloroquine-induced zinc uptake. Fluorescent microscopic examination of intracellular zinc distribution demonstrated that free zinc ions are more concentrated in the lysosomes after addition of chloroquine, which is consistent with previous reports showing that chloroquine inhibits lysosome function. The combination of chloroquine with zinc enhanced chloroquine's cytotoxicity and induced apoptosis in A2780 cells. Thus chloroquine is a zinc ionophore, a property that may contribute to chloroquine's anticancer activity.

Extraction and detection of Ionophores in the Aquatic Environment

DEFF Research Database (Denmark)

Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen

. Coccidiosis is a major disease in poultry as well as in many other hosts. Ionophores are the most heavily applied sup-group of the two sub-groups of anticoccidial agents, because they also have antibacterial properties. After the ban of antibiotic growth promoters Ionophores are used extensively worldwide......Anticoccidial agents or coccidiostatics are the only anti-bacterial substances still authorised as feed additives within the European Union (Vincent et al. 2011). Anticoccidial agents are used for the prevention of the disease coccidiosis, which is caused by a unicellular intestinal parasite...... as prophylactic chemotherapeutics and growth promoters in livestock production. As an example, the yearly consumptions of active compounds are more than 10 tonnes in Denmark and for the Republic of Korea more than 800 tonnes (Hansen et al. 2009a, Kim et al. 2008). In long term this could cause problems...

Genetic Screening Strategy for Rapid Access to Polyether Ionophore Producers and Products in Actinomycetes ▿ †

Science.gov (United States)

Wang, Hao; Liu, Ning; Xi, Lijun; Rong, Xiaoying; Ruan, Jisheng; Huang, Ying

2011-01-01

Polyether ionophores are a unique class of polyketides with broad-spectrum activity and outstanding potency for the control of drug-resistant bacteria and parasites, and they are produced exclusively by actinomycetes. A special epoxidase gene encoding a critical tailoring enzyme involved in the biosynthesis of these compounds has been found in all five of the complete gene clusters of polyether ionophores published so far. To detect potential producer strains of these antibiotics, a pair of degenerate primers was designed according to the conserved regions of the five known polyether epoxidases. A total of 44 putative polyether epoxidase gene-positive strains were obtained by the PCR-based screening of 1,068 actinomycetes isolated from eight different habitats and 236 reference strains encompassing eight major families of Actinomycetales. The isolates spanned a wide taxonomic diversity based on 16S rRNA gene analysis, and actinomycetes isolated from acidic soils seemed to be a promising source of polyether ionophores. Four genera were detected to contain putative polyether epoxidases, including Micromonospora, which has not previously been reported to produce polyether ionophores. The designed primers also detected putative epoxidase genes from diverse known producer strains that produce polyether ionophores unrelated to the five published gene clusters. Moreover, phylogenetic and chemical analyses showed a strong correlation between the sequence of polyether epoxidases and the structure of encoded polyethers. Thirteen positive isolates were proven to be polyether ionophore producers as expected, and two new analogues were found. These results demonstrate the feasibility of using this epoxidase gene screening strategy to aid the rapid identification of known products and the discovery of unknown polyethers in actinomycetes. PMID:21421776

ethane as ionophore in potentiometric sensor for Pb(II) ions

Indian Academy of Sciences (India)

tiometric sensors have attracted attention for their simple construction, low-cost, good ... of lead can cause serious health problems, includ- ing nervous system ... tripodal ionophore as a copper (II) selective electrode.16. Several studies have ...

Bradykinin and vasopressin activate phospholipase D in rat Leydig cells by a protein kinase C-dependent mechanism

DEFF Research Database (Denmark)

Vinggaard, Anne Marie; Hansen, Harald S.

1993-01-01

of PMA and vasopressin (AVP), PMA and bradykinin, or AVP and bradykinin produced no additive phosphatidylethanol or choline response, suggesting that AVP, bradykinin and PMA stimulated phospholipase D catalysed phosphatidylcholine hydrolysis by a similar protein kinase C-dependent mechanism. Furthermore......, LH (10 ng/ml), insulin (500 nmol/l), GH (100 ng/ml), interleukin-1ß (5 U/ml) and platelet-activating factor (200 nmol/l) were found not to activate phospholipase D, whereas the Ca ionophore A23187 (10 µmol/l) stimulated phosphatidylethanol formation, suggesting that Ca might be a regulator...

Caspase activity and apoptotic signaling in proliferating C2C12 cells following cisplatin or A23187 exposure

Directory of Open Access Journals (Sweden)

Darin Bloemberg

2016-06-01

Full Text Available Investigating cell death signaling using cell culture is commonly performed to examine the effects of novel pharmaceuticals or to further characterize discrete cellular signaling pathways. Here, we provide data regarding the cell death response to either cisplatin or A23187 in sub-confluent C2C12 cells, by utilizing several concentrations and incubation times for each chemical. These data include an assessment of the activation of the proteolytic enzymes caspase-3, caspase-8, caspase-9, calpain, and cathepsin B/L. Additionally, the expression of the apoptosis-regulating proteins Bax, Bcl2, and p53 are presented.

Extraction or adsorption? Voltammetric assessment of protamine transfer at ionophore-based polymeric membranes.

Science.gov (United States)

Garada, Mohammed B; Kabagambe, Benjamin; Amemiya, Shigeru

2015-01-01

Cation-exchange extraction of polypeptide protamine from water into an ionophore-based polymeric membrane has been hypothesized as the origin of a potentiometric sensor response to this important heparin antidote. Here, we apply ion-transfer voltammetry not only to confirm protamine extraction into ionophore-doped polymeric membranes but also to reveal protamine adsorption at the membrane/water interface. Protamine adsorption is thermodynamically more favorable than protamine extraction as shown by cyclic voltammetry at plasticized poly(vinyl chloride) membranes containing dinonylnaphthalenesulfonate as a protamine-selective ionophore. Reversible adsorption of protamine at low concentrations down to 0.038 μg/mL is demonstrated by stripping voltammetry. Adsorptive preconcentration of protamine at the membrane/water interface is quantitatively modeled by using the Frumkin adsorption isotherm. We apply this model to ensure that stripping voltammograms are based on desorption of all protamine molecules that are transferred across the interface during a preconcentration step. In comparison to adsorption, voltammetric extraction of protamine requires ∼0.2 V more negative potentials, where a potentiometric super-Nernstian response to protamine is also observed. This agreement confirms that the potentiometric protamine response is based on protamine extraction. The voltammetrically reversible protamine extraction results in an apparently irreversible potentiometric response to protamine because back-extraction of protamine from the membrane extremely slows down at the mixed potential based on cation-exchange extraction of protamine. Significantly, this study demonstrates the advantages of ion-transfer voltammetry over potentiometry to quantitatively and mechanistically assess protamine transfer at ionophore-based polymeric membranes as foundation for reversible, selective, and sensitive detection of protamine.

ethane as ionophore in potentiometric sensor for Pb(II) ions

Indian Academy of Sciences (India)

solvent media up to 30% (v/v) non-aqueous contents. Selectivity of the ... PVC; neutral carrier; ionophore; liquid membrane; lead ions; selectivity coefficients; Nernstian ... Health Organization (WHO) and US Environmental ... The first new tripo-.

Quartz crystal microbalance sensor using ionophore for ammonium ion detection.

Science.gov (United States)

Kosaki, Yasuhiro; Takano, Kosuke; Citterio, Daniel; Suzuki, Koji; Shiratori, Seimei

2012-01-01

Ionophore-based quartz crystal microbalance (QCM) ammonium ion sensors with a detection limit for ammonium ion concentrations as low as 2.2 microM were fabricated. Ionophores are molecules, which selectively bind a particular ion. In this study, one of the known ionophores for ammonium, nonactin, was used to detect ammonium ions for environmental in-situ monitoring of aquarium water for the first time. To fabricate the sensing films, poly(vinyl chloride) was used as the matrix for the immobilization of nonactin. Furthermore, the anionic additive, tetrakis (4-chlorophenyl) borate potassium salt and the plasticizer dioctyl sebacate were used to enhance the sensor properties. The sensor allowed detecting ammonium ions not only in static solution, but also in flowing water. The sensor showed a nearly linear response with the increase of the ammonium ion concentration. The QCM resonance frequency increased with the increase of ammonium ion concentration, suggesting a decreasing weight of the sensing film. The detailed response mechanism could not be verified yet. However, from the results obtained when using a different plasticizer, nitrophenyl octyl ether, it is considered that this effect is caused by the release of water molecules. Consequently, the newly fabricated sensor detects ammonium ions by discharge of water. It shows high selectivity over potassium and sodium ions. We conclude that the newly fabricated sensor can be applied for detecting ammonium ions in aquarium water, since it allows measuring low ammonium ion concentrations. This sensor will be usable for water quality monitoring and controlling.

Salinomycin and Other Polyether Ionophores Are a New Class of Antiscarring Agent*

Science.gov (United States)

Woeller, Collynn F.; O'Loughlin, Charles W.; Roztocil, Elisa; Feldon, Steven E.; Phipps, Richard P.

2015-01-01

Although scarring is a component of wound healing, excessive scar formation is a debilitating condition that results in pain, loss of tissue function, and even death. Many tissues, including the lungs, heart, skin, and eyes, can develop excessive scar tissue as a result of tissue injury, chronic inflammation, or autoimmune disease. Unfortunately, there are few, if any, effective treatments to prevent excess scarring, and new treatment strategies are needed. Using HEK293FT cells stably transfected with a TGFβ-dependent luciferase reporter, we performed a small molecule screen to identify novel compounds with antiscarring activity. We discovered that the polyether ionophore salinomycin potently inhibited the formation of scar-forming myofibroblasts. Salinomycin (250 nm) blocked TGFβ-dependent expression of the cardinal myofibroblast products α smooth muscle actin, calponin, and collagen in primary human fibroblasts without causing cell death. Salinomycin blocked phosphorylation and activation of TAK1 and p38, two proteins fundamentally involved in signaling myofibroblast and scar formation. Expression of constitutively active mitogen activated kinase kinase 6, which activates p38 MAPK, attenuated the ability of salinomycin to block myofibroblast formation, demonstrating that salinomycin targets the p38 kinase pathway to disrupt TGFβ signaling. These data identify salinomycin and other polyether ionophores as novel potential antiscarring therapeutics. PMID:25538236

Crown bridged thiacalix[4]arenes as cesium-selective ionophores in solvent polymeric membrane electrodes

International Nuclear Information System (INIS)

Bereczki, Robert; Csokai, Viktor; Gruen, Alajos; Bitter, Istvan; Toth, Klara

2006-01-01

Novel 1,3-alternate thiacalix[4]mono- and biscrown-6 ethers were studied as ionophores in poly(vinyl chloride) membrane electrodes. Their selectivity behavior was characterized with respect to large number of cations, including potential interferents in environmental samples, and the membrane composition was optimized for cesium ion response. Among the ionophores, 1,3-alternate thiacalix[4]mono(crown-6) ether showed, especially high selectivity for cesium over other alkali-metal ions. Transition and heavy metal ions did not interfere seriously with the electrode response, which indicates that the bridging sulfur atoms do not take part in the ion recognition process. The potentiometric cesium responses of all electrodes involved in this study were found close to Nernstian and the detection limits were lower than 10 -7 M. The Cs + /Na + selectivity of the different ionophore-based sensors and the solvent extraction ability of the ligands were interpreted based on the respective constants of complex formation

Genetic Screening Strategy for Rapid Access to Polyether Ionophore Producers and Products in Actinomycetes ▿ †

OpenAIRE

Wang, Hao; Liu, Ning; Xi, Lijun; Rong, Xiaoying; Ruan, Jisheng; Huang, Ying

2011-01-01

Polyether ionophores are a unique class of polyketides with broad-spectrum activity and outstanding potency for the control of drug-resistant bacteria and parasites, and they are produced exclusively by actinomycetes. A special epoxidase gene encoding a critical tailoring enzyme involved in the biosynthesis of these compounds has been found in all five of the complete gene clusters of polyether ionophores published so far. To detect potential producer strains of these antibiotics, a pair of d...

Ion-Selective Electrodes for the Potentiometric Determination of Pramoxine HCl Using Different Ionophores.

Science.gov (United States)

Ramadan, Nesrin K; Merey, Hanan A

2012-12-01

Four novel pramoxine HCl (PAM) selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using sodium-tetraphenylborate (TPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl -cyclodextrin as an ionophore, while sensors 3 and 4 were constructed using 4-sulfocalix-6-arene and 4-sulfocalix-8-arene respectively as ionophores. Linear responses of PAM within the concentration ranges of 1.0 × 10-4 to 1.0 × 10-2 mol L-1 and 1.0 × 10-5 to 1.0 × 10-2 mol L-1 were obtained using sensors 1 and 2, respectively and 1.0 × 10-6 to 1.0 × 10-2 mol L-1 were obtained using sensors 3 and 4. Nernstian slopes of 50.4 ± 0.6, 54.3 ± 0.8, 56.3 ± 0.3 and 59.1 ± 0.5 mV/decade over the pH range of 3.0-6.0 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for PAM. The utility of 2-hydroxy- propylcyclodextrin (2HP-β-CD) and 4-sulfocalix [6,8] arene (SC 6, 8) as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2, 3 and 4 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of PAM in bulk powder, pharmaceutical formulation, and in biological fluid. Validation of the method showed the suitability of the proposed electrodes for the use in the quality control assessment of the drug. Furthermore, statistical comparison between the results obtained by the proposed method and the official method of the drug was performed and no significant difference was found.

Peritoneal fluid modulates the sperm acrosomal exocytosis induced by N-acetylglucosaminyl neoglycoprotein

Directory of Open Access Journals (Sweden)

E.P. Passos

1999-01-01

Full Text Available The effect of peritoneal fluid (PF on the human sperm acrosome reaction (AR was tested. Sperm was pre-incubated with PF and the AR was induced by calcium ionophore A23187 and a neoglycoprotein bearing N-acetylglycosamine residues (NGP. The AR induced by calcium ionophore was inhibited 40% by PF from controls (PFc and 50% by PF from the endometriosis (PFe group, but not by PF from infertile patients without endometriosis (PFi. No significant differences were found in the spontaneous AR. When the AR was induced by NGP, pre-incubation with PFc reduced (60% the percentage of AR, while PFe and PFi caused no significant differences. The average rates of acrosome reactions obtained in control, NGP- and ionophore-treated sperm showed that NGP-induced exocytosis differed significantly between the PFc (11% and PFe/PFi groups (17%, and the ionophore-induced AR was higher for PFi (33% than PFc/PFe (25%. The incidence of the NGP-induced AR was reduced in the first hour of pre-incubation with PFc and remained nearly constant throughout 4 h of incubation. The present data indicate that PF possesses a protective factor which prevents premature AR.

Salinomycin and other polyether ionophores are a new class of antiscarring agent.

Science.gov (United States)

Woeller, Collynn F; O'Loughlin, Charles W; Roztocil, Elisa; Feldon, Steven E; Phipps, Richard P

2015-02-06

Although scarring is a component of wound healing, excessive scar formation is a debilitating condition that results in pain, loss of tissue function, and even death. Many tissues, including the lungs, heart, skin, and eyes, can develop excessive scar tissue as a result of tissue injury, chronic inflammation, or autoimmune disease. Unfortunately, there are few, if any, effective treatments to prevent excess scarring, and new treatment strategies are needed. Using HEK293FT cells stably transfected with a TGFβ-dependent luciferase reporter, we performed a small molecule screen to identify novel compounds with antiscarring activity. We discovered that the polyether ionophore salinomycin potently inhibited the formation of scar-forming myofibroblasts. Salinomycin (250 nm) blocked TGFβ-dependent expression of the cardinal myofibroblast products α smooth muscle actin, calponin, and collagen in primary human fibroblasts without causing cell death. Salinomycin blocked phosphorylation and activation of TAK1 and p38, two proteins fundamentally involved in signaling myofibroblast and scar formation. Expression of constitutively active mitogen activated kinase kinase 6, which activates p38 MAPK, attenuated the ability of salinomycin to block myofibroblast formation, demonstrating that salinomycin targets the p38 kinase pathway to disrupt TGFβ signaling. These data identify salinomycin and other polyether ionophores as novel potential antiscarring therapeutics. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Effects of ionophores and antibiotics on in vitro hydrogen sulfide production, dry matter disappearance, and total gas production in cultures with a steam-flaked corn-based substrate with or without added sulfur.

Science.gov (United States)

Quinn, M J; May, M L; Hales, K E; DiLorenzo, N; Leibovich, J; Smith, D R; Galyean, M L

2009-05-01

Effects of 3 ionophores and 2 antibiotics on in vitro H(2)S production, IVDMD, total gas production, and VFA profile with or without added S were examined. In Exp. 1, ruminal fluid from 2 ruminally cannulated steers fed a steam-flaked corn-based diet (75% concentrate) without ionophore and antibiotics for 28 d before collection was used to inoculate in vitro cultures. Treatments were control (no ionophore or antibiotic), 3 ionophores (lasalocid sodium and monensin sodium at 5 mg/L or laidlomycin propionate at 1.65 mg/L), and 2 antibiotics (chlortetracycline hydrochloride at 5 mg/L and tylosin tartarate at 1.25 mg/L). Cultures also had 0 or 1.75 mg of S/L (from sodium sulfate). No S x ionophore-antibiotic treatment interactions were noted (P > 0.53) for IVDMD, total gas production, and H(2)S production. Hydrogen sulfide (mumol/g of fermentable DM) was increased (P production tended (P = 0.09) to be increased with additional S; however, IVDMD was not affected by added S (P = 0.90). Production of H(2)S was not affected by ionophores or antibiotics (P > 0.18). On average, IVDMD (P = 0.05) was greater for ionophores than for antibiotics, whereas total gas production was less for ionophores than for control (P antibiotics (P 0.20) in acetate, propionate, or acetate:propionate between ionophores and control (S x treatment interaction, P = 0.03). In Exp. 2, the effects of ionophore-antibiotic combinations with added S were examined using the same procedures as in Exp. 1. Treatments were control, monensin plus tylosin (MT), and lasalocid plus chlortetracycline (LCTC), with concentrations of the ionophores and antibiotics as in Exp. 1. No differences were observed among treatments for H(2)S production (P > 0.55). Treatments MT and LCTC tended (P = 0.06) to increase IVDMD and decreased (P = 0.02) gas production vs. control. Proportion of acetate (P = 0.01) and acetate:propionate (P antibiotics we evaluated did not affect production of H(2)S gas in an in vitro rumen culture

Active calcium transport in plasma membrane vesicles from developing cotyledons of common bean

International Nuclear Information System (INIS)

Huang Jianzhong; Chen Ziyuan

1995-01-01

Plasma membrane vesicles were prepared from the developing cotyledons of common bean (Phaseolus vulgaris L cv Diyundou) by aqueous two-phase partitioning and characterized as to their purity by assaying marker enzymes for other membranes. The putative plasma membrane fraction was minimally contaminated by membranes other than plasma membrane and hence was of high purity. It exhibited a Ca 2+ -dependent ATPase activity, which was inhibited by 1 μmol/L EB and promoted by calcium ionophore A23187. Such an activity was responsible for the observed ATP-dependent 45 Ca 2+ uptake into inside-out plasma membrane vesicles. This process was stimulated by 0.6 μmol/L CaM and 20 μmol/L IAA but inhibited by 2 μmol/L ABA and abolished by A23187. Possible role of cytoplasmic Ca 2+ in mediating phytohormones activity is discussed

Modulation of neutrophil superoxide generation by inhibitors of protein kinase C, calmodulin, diacylglycerol and myosin light chain kinases, and peptidyl prolyl cis-trans isomerase.

Science.gov (United States)

Bergstrand, H; Eriksson, T; Hallberg, A; Johansson, B; Karabelas, K; Michelsen, P; Nybom, A

1992-12-01

To assess the role of protein kinase C (PKC) in the respiratory burst of adherent human polymorphonuclear leukocytes (PMNL), reduction of ferricytochrome C by cells triggered with a phorbol ester (PMA), ionophore A23187, serum-treated zymosan (STZ) or three lipid derivatives, 3-decanoyl-sn-glycerol (G-3-OCOC9), (R,R)-1,4-diethyl-2-O-decyl-L-tartrate (Tt-2-OC10) and 3-decyloxy-5-hydroxymethylphenol (DHP) was examined in a microtiter plate procedure in the presence of inhibitors of PKC and, for comparison, inhibitors of calmodulin, diacylglycerol and myosin light chain kinases and the peptidyl-prolyl cis-trans isomerase activity of fujiphilin. 1) Of the protein kinase inhibitors examined, Ro 31-7549 and staurosporine reduced responses to all stimuli except possibly STZ; in contrast, K252a and the myosin light chain kinase inhibitors ML-7 and ML-9 blocked responses to A23187 and STZ better than those triggered by PMA. H-7 reduced responses to A23187, DHP and G-3-OCOC9, and calphostin, palmitoyl carnitine, sphingosine and the multifunctional drugs TMB-8 and W-7 reduced A23187; they also, when examined, reduced decane derivative-induced O2- production more effectively than PMA- and STZ-triggered responses. Polymyxin B, 4 alpha-PMA and retinal displayed no inhibitory capacity. 2) Of the selective calmodulin antagonists, CGS 9343B, Ro 22-4839 and calmidazolium did not inhibit the oxidative response irrespective of the stimulus used, whereas metofenazate reduced those evoked by A23187, DHP, G-3-OCOC9 and STZ.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of amiloride on arachidonic acid and histamine release from rat mast cells

DEFF Research Database (Denmark)

Linnebjerg, H.; Hansen, Harald S.; Jensen, B.

1989-01-01

The effect of a putative Na/H exchange inhibition on histamine and [C]arachidonic acid ([C]AA) release has been examined in rat peritoneal mast cells, using either addition of amiloride or removal of extracellular Na. The cells were stimulated by non-immunological agents, i.e. calcium ionophore A......23187, nerve growth factor (NGF), thapsigargin and compound 48/80. On the basis of the results obtained, a possible role for Na/H exchange in rat mast cell secretion is discussed....

Arachidonic acid metabolism in fibroblasts derived from canine myocardium

International Nuclear Information System (INIS)

Weber, D.R.; Prescott, S.M.

1986-01-01

Canine fibroblasts from normal or healing infarcted myocardium were grown in culture. The cells were morphologically indistinguishable, but the doubling time of cells from healing myocardium was 39.6 +/- 3.5 hr whereas that of normals was 24 +/- 3.7 (n=5, p 3 H]arachidonate (AA) into phospholipids. Calcium ionophore A23187 (10 μM) caused release and metabolism of [ 3 H] AA. A23187 or AA (10μM) induced production of 6-keto PGF1α, PGE2, and a hydroxy metabolite of AA. RIA of 6-keto PGF1α showed that subconfluent cells from healing myocardium produced 1202 +/- 354 pg/mg protein whereas that of normals was 551 +/- 222 (n=7, p 3 H]AA released but did not metabolize [ 3 H]AA. In coincubations, fibroblasts incorporated myocyte-derived AA. Subsequent stimulation of the fibroblasts with A23187 induced the synthesis of 6-keto PGF1α, PGE2 and a hydroxy metabolite. The fibroblast content of healing myocardium was 35-1000 times that of normal tissue (n=7). Thus even a moderate change in AA metabolism, amplified by the AA released from deteriorating myocytes, may be a significant physiologic or pathologic event

Experimental and theoretical study on complexation of Li+ with lithium ionophore VIII

Czech Academy of Sciences Publication Activity Database

Makrlík, E.; Novák, V.; Vaňura, P.; Bouř, Petr

2013-01-01

Roč. 144, č. 11 (2013), s. 1607-1611 ISSN 0026-9247 Institutional support: RVO:61388963 Keywords : ionophores * macrocycles * complexation * DFT calculations * structures Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.347, year: 2013

The effect of intracellular calcium level regulators on the synthesis of pollen tube callose in Oenothera biennis L.

Directory of Open Access Journals (Sweden)

Elżbieta Bednarska

2014-01-01

Full Text Available It is shown that callose synthesis in the Oenothera biennis pollen tube is regulated by the endogenous Ca2+ level. Calcium antagonists reduced the amount of callose in the wall above the tip of the pollen tube (Verapamil - calcium channels blocker and at the tube tip after stopping tube growth (La3+ - a Ca2+ substitute. Ruthenium red and ionophore A 23187, which raise the Ca 21 level in the cytoplasm, induced callose synthesis at the tip of pollen tube.

Highly selective thiocyanate optochemical sensor based on manganese(III)-salophen ionophore

International Nuclear Information System (INIS)

Abdel-Haleem, Fatehy M.; Rizk, Mahmoud S.

2017-01-01

We report on the development of optochemical sensor based on Mn(III)-salophen ionophore. The sensor was prepared by embedding the ionophore in a plasticized poly (vinyl chloride) impregnated with the chromoionophore ETH7075. Optical response to thiocyanate occurred due to thiocyanate extraction into the polymer via formation of strong complex with the ionophore and simultaneous protonation of the indicator dye yielding the optical response at 545 nm. The developed optochemical sensor exhibited high selectivity for thiocyanate over other anions including the most lipophilic species such as salicylate and perchlorate. For instance, the optical selectivity coefficients, logK SCN,anion opt , were as follow: ClO 4 − = − 5.8; Sal − = − 4.0; NO 3 − ˂ − 6. Further, the thiocyanate optical selectivity obtained using the present optochemical sensor was greatly enhanced in comparison with that obtained using an anion-exchanger based sensor. Also, the optimized optochemical sensor exhibited micro-molar detection limit with 2 min response time at pH 4.5 using acetate buffer. The reversibility of the optimized sensor was poor due to strong ligation of the thiocyanate to the central Metal ion, log K = 14.1, which can be overcome by soaking the optode in sodium hydroxide followed by soaking in buffer solution. The developed sensor was utilized successfully for the determination of thiocyanate in human saliva and in spiked saliva samples. - Highlights: • Preparation of different optodes using different compositions • Mechanism depends on co-extraction of thiocyanate and protons to membrane. • Sensor showed excellent selectivity. • Sensor could be applied for thiocyanate determination in real saliva.

Highly selective thiocyanate optochemical sensor based on manganese(III)-salophen ionophore

Energy Technology Data Exchange (ETDEWEB)

Abdel-Haleem, Fatehy M., E-mail: fatehy@sci.cu.edu.eg; Rizk, Mahmoud S.

2017-06-01

We report on the development of optochemical sensor based on Mn(III)-salophen ionophore. The sensor was prepared by embedding the ionophore in a plasticized poly (vinyl chloride) impregnated with the chromoionophore ETH7075. Optical response to thiocyanate occurred due to thiocyanate extraction into the polymer via formation of strong complex with the ionophore and simultaneous protonation of the indicator dye yielding the optical response at 545 nm. The developed optochemical sensor exhibited high selectivity for thiocyanate over other anions including the most lipophilic species such as salicylate and perchlorate. For instance, the optical selectivity coefficients, logK{sub SCN,anion}{sup opt}, were as follow: ClO{sub 4}{sup −} = − 5.8; Sal{sup −} = − 4.0; NO{sub 3}{sup −} ˂ − 6. Further, the thiocyanate optical selectivity obtained using the present optochemical sensor was greatly enhanced in comparison with that obtained using an anion-exchanger based sensor. Also, the optimized optochemical sensor exhibited micro-molar detection limit with 2 min response time at pH 4.5 using acetate buffer. The reversibility of the optimized sensor was poor due to strong ligation of the thiocyanate to the central Metal ion, log K = 14.1, which can be overcome by soaking the optode in sodium hydroxide followed by soaking in buffer solution. The developed sensor was utilized successfully for the determination of thiocyanate in human saliva and in spiked saliva samples. - Highlights: • Preparation of different optodes using different compositions • Mechanism depends on co-extraction of thiocyanate and protons to membrane. • Sensor showed excellent selectivity. • Sensor could be applied for thiocyanate determination in real saliva.

Role of calcium in phosphoinositide metabolism and inhibition of norepinephrine transport into synaptic vesicles by amphetamine analogs

International Nuclear Information System (INIS)

Knepper, S.M.

1985-01-01

Norepinephrine-(NE) and calcium ionophore A23187-stimulated phosphoinositide (PIn) metabolism in rat brain slices was studied under varying calcium conditions. Tissue was labelled with 3 H-myo-inositol and 3 H-inositol phosphates (IPn), products of PIn metabolism were measured. In the absence of media calcium the response to NE was decreased while that to A23187 was little affected A23187 can release calcium from intracellular stores. Basal and stimulated accumulation of 3 H-IPn was reversibly antagonized with EGTA by addition of calcium. Using calcium buffers, approximately 10 -7 M free calcium was required to support hydrolysis. Free intracellular calcium is maintained at approximately this level. Thus calcium is required for PIn hydrolysis but appears to play a permissive role, basal levels being sufficient to support metabolism. Conformationally-defined (rigid) and -restricted (semi-rigid) analogs of the most stable conformations of amphetamine, antiperiplanar (exo) and gauche (endo), were utilized to probe the conformational requirements of vesicular NE transport. Analogs tested were 2-aminotetralin (2AT), 3-methyltetrahydroisoquinoline, anti- and syn-9-aminobenzobicyclo[2.2.1]heptene, and endo and exo conformers of 2-aminobenzobicyclo[2.2.1]heptene and 2-aminobenzobicyclo[2.2.2]octene

[Effect of damage integrity rat brain synaptic membranes on the functional activity GABA(A)-receptor/Cl(-)-ionophore complex in the CNC].

Science.gov (United States)

Rebrov, I G; Kalinina, M V

2013-01-01

Functional activity of the CGABA(A)-receptor/Cl(-) ionophore complex was investigated the muscimol-stimulated entry of the radioactive isotope 36Cl(-) in synaptoneurosomes in changing the structure and permeability of neuronal membranes. Integrity of the membranes was damaged by removal of Ca(+2) and Mg(+2) from the incubation medium and by the method of freezing-thawing synaptoneurosomes. In both cases, an increase in basal 36Cl(-) entry into synaptoneurosomes, indicating increased nonspecific permeability of neuronal membranes, and decreased activity the CABA(A)-receptor/Cl(-) ionophore complex. The conclusion about the relationship of processes damage neuronal membranes and reducing the inhibitory processes in the epileptic focus.

Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction

DEFF Research Database (Denmark)

Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk

2013-01-01

A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid...

[Inhibition of phospholipase A2 of peritoneal macrophages in rats by 1,2-di-O-hexadecyl-rac-glycero-3-phosphocholine].

Science.gov (United States)

Boucrot, P; Khettab, E N; Petit, J Y; Welin, L

1993-01-01

The 1-O-stearoyl-2-O-[3H] arachidonyl-sn-glycero-3-phosphocholine, introduced in the culture medium, was taken up by the peritoneal macrophages activated by the ionophore A 23187. After intracellular phospholipase A2 activity, the [3H] arachidonic acid was found in cells and in extracellular fluids. It also reached the eicosanoid synthesis. When it was introduced in the culture medium with the tritiated phospholipid, the 1, 2 di-O-hexadecyl-rac-glycero-3-phosphocholine, which has a non hydrolysable alkylated structure in the 2 position of the glycerol, inhibited the intracellular phospholipase A2, then contributed to lower the eicosanoid synthesis.

Calcium-sensitive regulation of monoamine oxidase-A contributes to the production of peroxyradicals in hippocampal cultures: implications for Alzheimer disease-related pathology

Directory of Open Access Journals (Sweden)

Li XinMin

2007-09-01

Full Text Available Abstract Background Calcium (Ca2+ has recently been shown to selectively increase the activity of monoamine oxidase-A (MAO-A, a mitochondria-bound enzyme that generates peroxyradicals as a natural by-product of the deamination of neurotransmitters such as serotonin. It has also been suggested that increased intracellular free Ca2+ levels as well as MAO-A may be contributing to the oxidative stress associated with Alzheimer disease (AD. Results Incubation with Ca2+ selectively increases MAO-A enzymatic activity in protein extracts from mouse hippocampal HT-22 cell cultures. Treatment of HT-22 cultures with the Ca2+ ionophore A23187 also increases MAO-A activity, whereas overexpression of calbindin-D28K (CB-28K, a Ca2+-binding protein in brain that is greatly reduced in AD, decreases MAO-A activity. The effects of A23187 and CB-28K are both independent of any change in MAO-A protein or gene expression. The toxicity (via production of peroxyradicals and/or chromatin condensation associated with either A23187 or the AD-related β-amyloid peptide, which also increases free intracellular Ca2+, is attenuated by MAO-A inhibition in HT-22 cells as well as in primary hippocampal cultures. Conclusion These data suggest that increases in intracellular Ca2+ availability could contribute to a MAO-A-mediated mechanism with a role in AD-related oxidative stress.

Total digestibility and in situ degradability of bulky diets with the inclusion of ionophores or probiotics for cattle and buffaloes

Directory of Open Access Journals (Sweden)

Lúcia Maria Zeoula

2014-09-01

Full Text Available The effects of ionophores (monensin and probiotic (Saccharomyces cerevisiae + selenium + chromium in diets with 80% forage were evaluated on the digestibility of nutrients. Three buffaloes, Murrah (Bubalus bubalis and three cattle, Holstein (Bos taurus, with an average weight of 520 ± 30 kg and 480 ± 182 kg, respectively, with rumen cannula, over experimental design with two 3 x 3 Latin squares in a 3 x 2 factorial arrangement, with the absence or presence of additives: ionophore or probiotic and two species, were used. The internal flow indicator of fecal dry matter (DM was the acid insoluble ash. DM, crude protein (CP and neutral detergent fiber (NDF ruminal degradability of Tifton 85 hay was conducted for cattle and buffaloes. A diet containing probiotics had higher dry matter and organic matter digestibility in buffalo and cattle, indicating a good performance in bulky diets. The potential and effective dry matter degradability in diet with probiotic in buffaloes, were smaller than diet with ionophore, suggesting that there was a better digestion of nutrients in the intestine of these animals. The potential and effective degradability of neutral detergent fiber and crude protein in the diet containing ionophores were superior than diet containing probiotic. Buffaloes showed higher capacity of dry matter and fiber digestion than cattle.

A thiourea derivative as potential ionophore for copper sensing

Science.gov (United States)

Ying, Kook Shih; Heng, Lee Yook; Hassan, Nurul Izzaty; Hasbullah, Siti Aishah

2018-04-01

A new thiourea derivative, N1,N3-bis[[3,5-bis(trifluoromethyl)phenyl]carbamothioyl]isophthalamide (TPC), as a potential copper ionophore was investigated. TPC was immobilized via drop casting method into poly(n-butyl acrylate) pBA membrane and the sensor was characterized by potentiometric method. The sensor fabricated based on TPC showed a Nernstian response towards copper ion with the slope of 27.07±2.84 mV/decade in the range of 1.0×10-6 - 1.0-10-4 M and limit of detection of 6.24 × 10-7 M. In addition, based on the separate solution method (SSM), the logarithm selectivity coefficients were less than -3.00 for monovalent, divalent and trivalent cations that are present in the environmental water samples such as K+, Ca2+, Mg2+ and Fe3+. This confirmed that the sensor fabricated with TPC exhibited good sensitivity and selectivity towards copper ion.

Activation and regulation of arachidonic acid release in rabbit peritoneal neutrophils

International Nuclear Information System (INIS)

Tao, W.

1988-01-01

Arachidonic acid release in rabbit neutrophils can be enhanced by the addition of chemotactic fMet-Leu-Phe, platelet-activating factor, PAF, or the calcium ionophore A23187. Over 80% of the release [ 3 H]arachidonic acid comes from phosphatidylcholine and phosphatidylinositol. The release is dose-dependent and increases with increasing concentration of the stimulus. The A23187-induced release increases with increasing time of the stimulation. [ 3 H]arachidonic acid release, but not the rise in the concentration of intracellular calcium, is inhibited in pertussis toxin-treated neutrophils stimulated with PAF. The [ 3 H]arachidonic acid released by A23187 is potentiated while that release by fMET-Leu-Phe or PAF is inhibited in phorbol 12-myristate 13-acetate, PMA, treated rabbit neutrophils. The protein kinase C inhibitor 1-(5-isoquinoline sulfonyl)-2-methylpiperazine, H-7, has no effect on the potentiation by PMA of the A23187-induced release, it prevents the inhibition by PMA of the release produced by PAF or fMet-Leu-Phe. In addition, PMA increases arachidonic acid release in H-7-treated cells stimulated with fMet-Leu-Phe. The diacylglycerol kinase inhibitor R59022 increases the level of diacylglycerol in neutrophils stimulated with fMet-Leu-Phe. Furthermore, R59022 potentiates [ 3 H] arachidonic acid release produced by fMet-Leu-Phe. This potentiation is not inhibited by H-7, in fact, it is increased in H-7-treated neutrophils

Carbon monoxide inhibits omega-oxidation of leukotriene B4 by human polymorphonuclear leukocytes: evidence that catabolism of leukotriene B4 is mediated by a cytochrome P-450 enzyme.

Science.gov (United States)

Shak, S; Goldstein, I M

1984-09-17

Carbon monoxide significantly inhibits omega-oxidation of exogenous leukotriene B4 to 20-OH-leukotriene B4 and 20-COOH-leukotriene B4 by unstimulated polymorphonuclear leukocytes as well as omega-oxidation of leukotriene B4 that is generated when cells are stimulated with the calcium ionophore, A23187. Inhibition of omega-oxidation by carbon monoxide is concentration-dependent, completely reversible, and specific. Carbon monoxide does not affect synthesis of leukotriene B4 by stimulated polymorphonuclear leukocytes or other cell functions (i.e., degranulation, superoxide anion generation). These findings suggest that a cytochrome P-450 enzyme in human polymorphonuclear leukocytes is responsible for catabolizing leukotriene B4 by omega-oxidation.

A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

Energy Technology Data Exchange (ETDEWEB)

Abbas, Mohammad Nooredeen; Hend Samy Amer [National Research Centre, Cairo (Egypt)

2013-04-15

A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 Χ 10{sup -7} to 1 Χ 10{sup -2} M and a lower detection limit (LDL) of 1 Χ 10{sup -7} M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

Complexation of the cesium cation with lithium ionophore VIII: extraction and DFT study

Czech Academy of Sciences Publication Activity Database

Makrlík, E.; Novák, Vít; Vaňura, P.; Bouř, Petr

2013-01-01

Roč. 298, č. 3 (2013), s. 2065-2068 ISSN 0236-5731 Institutional support: RVO:61388963 Keywords : cesium cation * lithium ionophore VIII * complexation * extraction and stability constants * water-nitrobenzene system * DFT calculations * structures Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 1.415, year: 2013

Characterization of Anthraquinone-DerivedRedox Switchable Ionophores and Their Complexes with Li+, Na+, K+, Ca+, and Mg+ Metal Ions

Directory of Open Access Journals (Sweden)

Vaishali Vyas

2011-01-01

Full Text Available Anthraquinone derived redox switchable ionophores 1,5 bis (2-(2-(2-ethoxy ethoxy ethoxyanthracene-9,10-dione (V1 and 1,8-bis(2-(2-(2-ethoxyethoxyethoxy anthracene—9,10-dione (V2 have been used for isolation, extraction and liquid membrane transport studies of Li+, Na+, K+, Ca2+ and Mg2+ metal ions. These isolated complexes were characterized by melting point determination, CV and IR, 1H NMR spectral analysis. Ionophore V2 shows maximum shift in reduction potential (ΔE with Ca(Pic2. The observed sequence for the shifting in reduction potential (ΔE between V2 and their complexes is V2 calcium picrate (42 mV > V2 potassium picrate (33 mV > V2 lithium picrate (25 mV > V2 sodium picrate (18 mV > V2 magnesium picrate (15 mV. These findings are also supported by results of extraction, back extraction and transport studies. Ionophore V2 complexed with KPic and showed much higher extractability and selectivity towards K+ than V1. These synthetic ionophores show positive and negative cooperativity towards alkali and alkaline earth metal ions in reduced and oxidized state. Hence, this property can be used in selective separation and enrichment of metal ions using electrochemically driven ion transport.

Ionophore-based optical nanosensors incorporating hydrophobic carbon dots and a pH-sensitive quencher dye for sodium detection.

Science.gov (United States)

Galyean, A A; Behr, M R; Cash, K J

2018-01-21

Nanosensors present a biological monitoring method that is biocompatible, reversible, and nano-scale, and they offer many advantages over traditional organic indicators. Typical ionophore-based nanosensors incorporate nile-blue derivative pH indicators but suffer from photobleaching while quantum dot alternatives pose a potential toxicity risk. In order to address this challenge, sodium selective nanosensors containing carbon dots and a pH-sensitive quencher molecule were developed based on an ion-exchange theory and a decoupled recognition element from the pH indicator. Carbon dots were synthesized and integrated into nanosensors containing a pH-indicator, an analyte-binding ligand (ionophore), and a charge-balancing additive. These nanosensors are ion-selective against potassium (selectivity coefficient of 0.4) and lithium (selectivity coefficient of 0.9). Reversible nanosensor response to sodium is also demonstrated. The carbon dot nanosensors are resistant to changes in optical properties for at least 12 h and display stable selectivity to physiologically-relevant sodium (alpha = 0.5 of 200 mM NaCl) for a minimum of 6 days.

Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

Directory of Open Access Journals (Sweden)

Tanabe Makoto

2011-09-01

Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin

Science.gov (United States)

2011-01-01

Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II) and lead(II). Results New metal(II) complexes of the polyether ionophorous antibiotic salinomycin with Cd(II) and Pb(II) ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa) undergoes a reaction with heavy metal(II) ions to form [Cd(Sal)2(H2O)2] (1) and [Pb(Sal)(NO3)] (2), respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II) ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II) center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II) cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II) complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock farming

Effects of secretagogues on ATP levels and protein carboxyl methylation in rat brain synaptosomes

International Nuclear Information System (INIS)

Bjorndahl, J.M.; Rutledge, C.O.

1986-01-01

The influence of various substances which are known to alter free intracellular calcium concentrations on protein carboxyl methyltransferase (PCM) activity was investigated in rat brain synaptosomes. The synaptosomes were labeled with L-[ 3 H]methionine and the 3 H-methyl esters of proteins were formed from the methyl donor S-[ 3 H]adenosyl-L-methionine ([ 3 H]AdoMet). The calcium ionophore A23187 and ouabain decreased PCM activity and the decrease produced by A23187 was antagonized by ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid and MnCl 2 . On the other hand, ruthenium red, an inhibitor of calcium uptake, stimulated PCM activity. These data suggest that PCM activity is inversely related to the free cytoplasmic calcium concentration. Veratridine, A23187 and elevated potassium ions decreased the levels of ATP and [ 3 H]AdoMet. The A23187-mediated decrease in ATP levels and the reduced [ 3 H]AdoMet formation was antagonized by ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid and MnCl 2 . Inhibition of metabolic activity of the synaptosomes by NaCN led to: decreased ATP levels; inhibition of [3H]AdoMet formation; and inhibition of PCM activity. These data suggest that the decrease in protein methylation produced by secretagogues is associated with an increase in the concentration of free intracellular calcium which results in a decrease in the metabolically active pool of ATP. This leads to a decreased rate of AdoMet formation, a cosubstrate for PCM and a resultant decrease in PCM activity

Comparative study of 2-hydroxy propyl beta cyclodextrin and calixarene as ionophores in potentiometric ion-selective electrodes for neostigmine bromide.

Science.gov (United States)

El-Kosasy, Amira M; Nebsen, Marianne; Abd El-Rahman, Mohamed K; Salem, Maissa Y; El-Bardicy, Mohamed G

2011-08-15

Three novel neostigmine bromide (NEO) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using tetrakis(4-chlorophenyl)borate (TpClPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor 3 was constructed using 4-sulfocalix-8-arene as an ionophore. Linear responses of NEO within the concentration ranges of 10(-5) to 10(-2), 10(-6) to 10(-2) and 10(-7) to 10(-2) mol L(-1) were obtained using sensors 1, 2 and 3, respectively. Nernstian slopes of 51.6 ± 0.8, 52.9 ± 0.6 and 58.6 ± 0.4 mV/decade over the pH range of 4-9 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for NEO. The utility of 2-hydroxy propyl β-cyclodextrin and 4-sulfocalix[8]arene as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2 and 3 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of NEO in bulk powder, different pharmaceutical formulations, and biological fluids (plasma and cerebrospinal fluid (CSF)) and in the presence of its degradation product (3-hydroxyphenyltrimethyl ammonium bromide) and thus could be used for stability-indicating methods. Copyright © 2011 Elsevier B.V. All rights reserved.

Precursor Ion Scan Mode-Based Strategy for Fast Screening of Polyether Ionophores by Copper-Induced Gas-Phase Radical Fragmentation Reactions.

Science.gov (United States)

Crevelin, Eduardo J; Possato, Bruna; Lopes, João L C; Lopes, Norberto P; Crotti, Antônio E M

2017-04-04

The potential of copper(II) to induce gas-phase fragmentation reactions in macrotetrolides, a class of polyether ionophores produced by Streptomyces species, was investigated by accurate-mass electrospray tandem mass spectrometry (ESI-MS/MS). Copper(II)/copper(I) transition directly induced production of diagnostic acylium ions with m/z 199, 185, 181, and 167 from α-cleavages of [macrotetrolides + Cu] 2+ . A UPLC-ESI-MS/MS methodology based on the precursor ion scan of these acylium ions was developed and successfully used to identify isodinactin (1), trinactin (2), and tetranactin (3) in a crude extract of Streptomyces sp. AMC 23 in the precursor ion scan mode. In addition, copper(II) was also used to induce radical fragmentation reactions in the carboxylic acid polyether ionophore nigericin. The resulting product ions with m/z 755 and 585 helped to identify nigericin in a crude extract of Streptomyces sp. Eucal-26 by means of precursor ion scan experiments, demonstrating that copper-induced fragmentation reactions can potentially identify different classes of polyether ionophores rapidly and selectively.

Evaluation of ionophore sensitivity of Eimeria acervulina and Eimeria maxima isolated from the Algerian to Jijel province poultry farms.

Science.gov (United States)

Djemai, Samir; Mekroud, Abdeslam; Jenkins, Mark C

2016-07-15

The present study represents the first description of ionophore resistance in recovered from commercial Algerian (Jijel-Algeria) broiler farms. Microscopy and intervening transcribed sequence 1 PCR (ITS1 PCR) revealed only 2 Eimeria species present in litter from these farms- namely Eimeria acervulina and Eimeria maxima. A pool of these isolates were evaluated in broiler chickens (Cobb 500) for sensitivity to 5 anticoccidial compounds-diclazuril (1ppm), lasalocid (125ppm), monensin (125ppm), narasin (70ppm) and salinomycin (60ppm). As indicated by anticoccidial sensitivity profiles based on lesion scores and anticoccidial index (ACI), complete resistance to monensin and narasin, partial resistance to salinomycin and lasalocid, and complete sensitivity to diclazuril was observed. While lack of sensitivity to monensin is not surprising given its use for years as the sole anticoccidial compound, the resistance to monoether (narasin) and polyether (lasalocid) ionophores suggests that cross-resistance has developed in a segment of the Eimeria population. The fairly uniform Eimeria species composition among all poultry farms suggests that E. acervulina and E. maxima more rapidly develop resistance to ionophore drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

Histamine release from cord blood basophils

DEFF Research Database (Denmark)

Nielsen, Bent Windelborg; Damsgaard, Tine Engberg; Herlin, Troels

1990-01-01

The histamine release (HR) after challenge with anti-IgE, concanavalin A, N-formyl-met-leu-phe and the calcium ionophore A23187 from 97 cord blood samples was determined by a microfiber-based assay. Maximum HR with anti-IgE showed great inter-individual variation (median: 20.5; range: 1-104 ng...... of less than 0.5 IU/ml, although sensitivity to anti-IgE was universally increased. Preincubation with pharmacologic agents modulating the IgE-mediated HR produced effects generally similar to previous findings in adult blood. However, the effects of inhibiting the cyclooxygenase pathway in cord blood...

Effect of ionophores on phosphate and arsenate transport in Micrococcus lysodeikticus

Energy Technology Data Exchange (ETDEWEB)

Friedberg, I

1977-09-01

The effects of ionophores on P/sub i/ and arsenate transport, at acid and alkaline environment, were investigated in whole cells of Micrococcus lysodeikticus, a Gram positive obligatory aerobic bacterium. The results suggest that both ..delta.. Psi and ..delta.. pH contribute to the driving force of P/sub i/ transport; ..delta.. Psi seems to be predominant at pH 7.8, whereas at pH 5.5, the transport is primarily driven by ..delta.. pH. 12 references, 1 figure.

Mitochondrial calcium uniporter silencing potentiates caspase-independent cell death in MDA-MB-231 breast cancer cells

Energy Technology Data Exchange (ETDEWEB)

Curry, Merril C.; Peters, Amelia A. [School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 (Australia); Kenny, Paraic A. [Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Roberts-Thomson, Sarah J. [School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 (Australia); Monteith, Gregory R., E-mail: gregm@uq.edu.au [School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 (Australia)

2013-05-10

Highlights: •Some clinical breast cancers are associated with MCU overexpression. •MCU silencing did not alter cell death initiated with the Bcl-2 inhibitor ABT-263. •MCU silencing potentiated caspase-independent cell death initiated by ionomycin. •MCU silencing promoted ionomycin-mediated cell death without changes in bulk Ca{sup 2+}. -- Abstract: The mitochondrial calcium uniporter (MCU) transports free ionic Ca{sup 2+} into the mitochondrial matrix. We assessed MCU expression in clinical breast cancer samples using microarray analysis and the consequences of MCU silencing in a breast cancer cell line. Our results indicate that estrogen receptor negative and basal-like breast cancers are characterized by elevated levels of MCU. Silencing of MCU expression in the basal-like MDA-MB-231 breast cancer cell line produced no change in proliferation or cell viability. However, distinct consequences of MCU silencing were seen on cell death pathways. Caspase-dependent cell death initiated by the Bcl-2 inhibitor ABT-263 was not altered by MCU silencing; whereas caspase-independent cell death induced by the calcium ionophore ionomycin was potentiated by MCU silencing. Measurement of cytosolic Ca{sup 2+} levels showed that the promotion of ionomycin-induced cell death by MCU silencing occurs independently of changes in bulk cytosolic Ca{sup 2+} levels. This study demonstrates that MCU overexpression is a feature of some breast cancers and that MCU overexpression may offer a survival advantage against some cell death pathways. MCU inhibitors may be a strategy to increase the effectiveness of therapies that act through the induction of caspase-independent cell death pathways in estrogen receptor negative and basal-like breast cancers.

Novel amide polar-embedded reversed-phase column for the fast liquid chromatography-tandem mass spectrometry method to determine polyether ionophores in environmental waters.

Science.gov (United States)

Herrero, P; Borrull, F; Pocurull, E; Marcé, R M

2012-11-09

A fast chromatographic method has been developed that takes less than 5 min per run to determine five polyether ionophores with a novel amide polar-embedded reversed-phase column coupled to a triple quadrupole mass spectrometer. A comparison between Oasis HLB and Oasis MAX sorbents for the solid-phase extraction was done. Oasis HLB sorbent gave recoveries close to 90% and the repeatability (%RSD, 25-100 ng/L, n=3) of the method was less than 7% for all compounds in all matrices. The presence of polyether ionophores in environmental waters such as river water and sewage was investigated. Monensin and narasin were frequently determined in influent and effluent sewage at concentrations from 10 ng/L to 47 ng/L in influents and from 6 ng/L to 34 ng/L in effluents. In river waters, polyether ionophores were not detected in any sample. Copyright © 2012 Elsevier B.V. All rights reserved.

Polymeric optical sensors for selective and sensitive nitrite detection using cobalt(III) corrole and rhodium(III) porphyrin as ionophores

Energy Technology Data Exchange (ETDEWEB)

Yang, Si; Wo, Yaqi; Meyerhoff, Mark E., E-mail: mmeyerho@umich.edu

2014-09-16

Highlights: • We examine cobalt(III) corroles and rhodium(III) porphyrins as ionophores in polymeric films for optical sensors to detect nitrite. • Different types of proton chromoionophores are evaluated to optimize nitrite response. • Selectivity over lipophilic anions such as perchlorate and thiocyanate is observed. • Both ionophores yield optical sensors that are fully reversible. • The cobalt(III) corrole based sensor is employed to determine nitric oxide emission rates from NO donor doped polymers with good accuracy. - Abstract: Cobalt(III) 5,10,15-tris(4-tert-butylphenyl) corrole with a triphenylphosphine axial ligand and rhodium(III) 5,10,15,20-tetra(p-tert-butylphenyl) porphyrin are incorporated into plasticized poly(vinyl chloride) films to fabricate nitrite-selective bulk optodes via absorbance measurements. The resulting films yield sensitive, fast and fully reversible response toward nitrite with significantly enhanced nitrite selectivity over other anions including lipophilic anions such as thiocyanate and perchlorate. The selectivity patterns differ greatly from the Hofmeister series based on anion lipophilicity and are consistent with selectivity obtained with potentiometric sensors based on the same ionophores. The optical nitrite sensors are shown to be useful for detecting rates of emission of nitric oxide (NO) from NO releasing polymers containing S-nitroso-N-acetyl-DL-penicillamine.

Monensin, a polyether ionophore antibiotic, overcomes TRAIL resistance in glioma cells via endoplasmic reticulum stress, DR5 upregulation and c-FLIP downregulation.

Science.gov (United States)

Yoon, Mi Jin; Kang, You Jung; Kim, In Young; Kim, Eun Hee; Lee, Ju Ahn; Lim, Jun Hee; Kwon, Taeg Kyu; Choi, Kyeong Sook

2013-08-01

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) is preferentially cytotoxic to cancer cells over normal cells. However, many cancer cells, including malignant glioma cells, tend to be resistant to TRAIL. Monensin (a polyether ionophore antibiotic that is widely used in veterinary medicine) and salinomycin (a compound that is structurally related to monensin and shows cancer stem cell-inhibiting activity) are currently recognized as anticancer drug candidates. In this study, we show that monensin effectively sensitizes various glioma cells, but not normal astrocytes, to TRAIL-mediated apoptosis; this occurs at least partly via monensin-induced endoplasmic reticulum (ER) stress, CHOP-mediated DR5 upregulation and proteasome-mediated downregulation of c-FLIP. Interestingly, other polyether antibiotics, such as salinomycin, nigericin, narasin and lasalocid A, also stimulated TRAIL-mediated apoptosis in glioma cells via ER stress, CHOP-mediated DR5 upregulation and c-FLIP downregulation. Taken together, these results suggest that combined treatment of glioma cells with TRAIL and polyether ionophore antibiotics may offer an effective therapeutic strategy.

Autoradiographic localization of GABA-regulated chloride ionophore binding site using t-[3H]butylbicycloorthobenzoate (TBOB)

International Nuclear Information System (INIS)

O'Connor, L.H.; McEwen, B.S.

1986-01-01

t-Butylbicycloorthobenzoate (TBOB) has been shown to bind with high affinity to sites on or near the chloride ionophore in rat brain membrane preparations. The present study used in vitro quantitative autoradiography to localize the regional distribution of [ 3 H]TBOB binding sites in rat forebrain. Receptors were labelled with 10 nM [ 3 H]TBOB. Nonspecific binding was determined by adding 10 μM picrotoxin to the incubation. Autoradiograms were generated using LKB Ultrofilm and then quantitated using computer-assisted spot-densitometry. The highest specific binding was found in frontal cortex layer 4, islands of Calleja, and ventral palladium. High binding was also found in many regions including anterior hypothalamic n., ventromedial hypothalamic n., dentate gyrus, stratum oriens and stratum lacunosum moleculare of hippocampus, and substantia nigra. Nonspecific binding represented 5 to 15% of total binding and was uniformly low throughout all brain regions. Thus, this selective probe for GABA-regulated chloride ionophore binding sites should provide a useful tool for characterizing this system and its relationship to convulsant and depressant drug action

Lithium ionophore VIII as an extraordinarily effective receptor for the strontium cation: Experimental and theoretical study

Czech Academy of Sciences Publication Activity Database

Makrlík, E.; Novák, Vít; Vaňura, P.; Bouř, Petr

2014-01-01

Roč. 1061, Mar 5 (2014), s. 110-113 ISSN 0022-2860 Institutional support: RVO:61388963 Keywords : strontium cation * lithium ionophore VIII * complexation * extraction and stability constants * DFT calculations * structures Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.602, year: 2014

Membrane properties involved in calcium-stimulated microparticle release from the plasma membranes of S49 lymphoma cells.

Science.gov (United States)

Campbell, Lauryl E; Nelson, Jennifer; Gibbons, Elizabeth; Judd, Allan M; Bell, John D

2014-01-01

This study answered the question of whether biophysical mechanisms for microparticle shedding discovered in platelets and erythrocytes also apply to nucleated cells: cytoskeletal disruption, potassium efflux, transbilayer phospholipid migration, and membrane disordering. The calcium ionophore, ionomycin, disrupted the actin cytoskeleton of S49 lymphoma cells and produced rapid release of microparticles. This release was significantly inhibited by interventions that impaired calcium-activated potassium current. Microparticle release was also greatly reduced in a lymphocyte cell line deficient in the expression of scramblase, the enzyme responsible for calcium-stimulated dismantling of the normal phospholipid transbilayer asymmetry. Rescue of the scrambling function at high ionophore concentration also resulted in enhanced particle shedding. The effect of membrane physical properties was addressed by varying the experimental temperature (32-42°C). A significant positive trend in the rate of microparticle release as a function of temperature was observed. Fluorescence experiments with trimethylammonium diphenylhexatriene and Patman revealed significant decrease in the level of apparent membrane order along that temperature range. These results demonstrated that biophysical mechanisms involved in microparticle release from platelets and erythrocytes apply also to lymphocytes.

Accessory signals in T-T cell interactions between antigen- and alloantigen-specific, human memory T cells generated in vitro

DEFF Research Database (Denmark)

Odum, N; Ryder, L P; Georgsen, J

1990-01-01

The potential of activated HLA class II-positive T cells as antigen-/alloantigen-presenting cells remains controversial. In our model system we use in vitro-primed, HLA class II-specific T cells of the memory T-cell phenotype, CD4+, CD29+ (4B4+), and CD45RO+ (UCHL-1). We have previously shown......), or a calcium ionophore (A23187) enabled Ta to elicit alloantigen-specific memory T-cell responses and to present purified protein derivative (PPD) to PPD-specific T-cell lines. The addition of irradiated, Epstein-Barr virus-transformed B-cell lines (EBV-LCL) (but not their supernatants) had a similar but less...

Biosynthetic machinery of ionophore polyether lasalocid: enzymatic construction of polyether skeleton.

Science.gov (United States)

Minami, Atsushi; Oguri, Hiroki; Watanabe, Kenji; Oikawa, Hideaki

2013-08-01

Diversity of natural polycyclic polyethers originated from very simple yet versatile strategy consisting of epoxidation of linear polyene followed by epoxide opening cascade. To understand two-step enzymatic transformations at molecular basis, a flavin containing monooxygenase (EPX) Lsd18 and an epoxide hydrolase (EH) Lsd19 were selected as model enzymes for extensive investigation on substrate specificity, catalytic mechanism, cofactor requirement and crystal structure. This pioneering study on prototypical lasalocid EPX and EH provides insight into detailed mechanism of ionophore polyether assembly machinery and clarified remaining issues for polyether biosynthesis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Determination of antibiotics such as macrolides, ionophores and tiamulin in liquid manure by HPLC-MS/MS.

Science.gov (United States)

Schlüsener, Michael P; Bester, Kai; Spiteller, Michael

2003-04-01

A method for the analysis of several macrolide and ionophore antibiotics as well as tiamulin in liquid manure was developed. Reversed-phase liquid chromatography and atmospheric pressure chemical ionisation (APCI) tandem mass spectrometry was used for detection.High-performance liquid chromatographic (HPLC) separation of the antibiotics was achieved in 35 min. The analytes were extracted with ethyl acetate and the extracts were cleaned up by solid-phase extraction on a diol SPE cartridge. Recovery experiments with spiked liquid manure concentrations varying from 6 to 2,000 microg kg(-1) gave constant recovery rates. The recovery rates for the macrolides erythromycin, roxithromycin and oleandomycin were 75-94%, that for the ionophore salinomycin was 119%, while that for the pleuromutilin tiamulin was 123%, when using a macrolide internal standard. The relative standard deviation was found to be 15-36% and the limits of detection were 0.4-11.0 micro g kg(-1). The maximum concentrations found in manure samples were 43 micro g kg(-1) for tiamulin and 11 micro g kg(-1) for salinomycin.

Modulation of basophils' degranulation and allergy-related enzymes by monomeric and dimeric naphthoquinones.

Directory of Open Access Journals (Sweden)

Brígida R Pinho

Full Text Available Allergic disorders are characterized by an abnormal immune response towards non-infectious substances, being associated with life quality reduction and potential life-threatening reactions. The increasing prevalence of allergic disorders demands for new and effective anti-allergic treatments. Here we test the anti-allergic potential of monomeric (juglone, menadione, naphthazarin, plumbagin and dimeric (diospyrin and diosquinone naphthoquinones. Inhibition of RBL-2H3 rat basophils' degranulation by naphthoquinones was assessed using two complementary stimuli: IgE/antigen and calcium ionophore A23187. Additionally, we tested for the inhibition of leukotrienes production in IgE/antigen-stimulated cells, and studied hyaluronidase and lipoxidase inhibition by naphthoquinones in cell-free assays. Naphthazarin (0.1 µM decreased degranulation induced by IgE/antigen but not A23187, suggesting a mechanism upstream of the calcium increase, unlike diospyrin (10 µM that reduced degranulation in A23187-stimulated cells. Naphthoquinones were weak hyaluronidase inhibitors, but all inhibited soybean lipoxidase with the most lipophilic diospyrin, diosquinone and menadione being the most potent, thus suggesting a mechanism of competition with natural lipophilic substrates. Menadione was the only naphthoquinone reducing leukotriene C4 production, with a maximal effect at 5 µM. This work expands the current knowledge on the biological properties of naphthoquinones, highlighting naphthazarin, diospyrin and menadione as potential lead compounds for structural modification in the process of improving and developing novel anti-allergic drugs.

Determination of regulatory ionophore coccidiostat residues in feedstuffs at carry-over levels by liquid chromatography-mass spectrometry

Science.gov (United States)

Stramenga, Arianna; Colagrande, Maria Novella; Campana, Guido; Scortichini, Giampiero; Migliorati, Giacomo; Compagnone, Dario

2017-01-01

In this study samples of feedstuffs were collected from different feed mills and animal farms located in central Italy and analyzed for ionophore coccidiostat residues at carry-over levels by liquid chromatography-mass spectrometry. Since unavoidable cross-contamination of feedstuffs may occur during their production as well as distribution and storage, the collection of samples covered all these different stages. Residues of lasalocid, monensin, salinomycin and maduramicin were detected in 32.4% of samples, both at production and storage level. The maximum content for unavoidable carry-over set by Regulation (EU) No 574/2011 was exceeded in 11.3% of samples. The variability of the results highlighted the different approach of each investigated feed business operator to avoid any cross-contamination in non-target feed. The method developed in this study can be able to detect ionophore coccidiostats at low concentrations consequent to carry-over. PMID:28792977

Nonsteroidal anti-inflammatory drug flufenamic acid is a potent activator of AMP-activated protein kinase.

Science.gov (United States)

Chi, Yuan; Li, Kai; Yan, Qiaojing; Koizumi, Schuichi; Shi, Liye; Takahashi, Shuhei; Zhu, Ying; Matsue, Hiroyuki; Takeda, Masayuki; Kitamura, Masanori; Yao, Jian

2011-10-01

Flufenamic acid (FFA) is a nonsteroidal anti-inflammatory drug (NSAID). It has anti-inflammatory and antipyretic properties. In addition, it modulates multiple channel activities. The mechanisms underlying the pharmacological actions of FFA are presently unclear. Given that AMP-activated protein kinase (AMPK) has both anti-inflammatory and channel-regulating functions, we examined whether FFA induces AMPK activation. 1) Exposure of several different types of cells to FFA resulted in an elevation of AMPKα phosphorylation at Thr172. This effect of FFA was reproduced by functionally and structurally similar mefenamic acid, tolfenamic acid, niflumic acid, and meclofenamic acid. 2) FFA-induced activation of AMPK was largely abolished by the treatment of cells with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (an intracellular Ca(2+) chelator) or depletion of extracellular Ca(2+), whereas it was mimicked by stimulation of cells with the Ca(2+) ionophore 5-(methylamino)-2-({(2R,3R,6S,8S,9R,11R)-3,9,11-trimethyl-8-[(1S)-1-methyl-2-oxo-2-(1H-pyrrol-2-yl)ethyl]-1,7-dioxaspiro[5.5]undec-2-yl}methyl)-1,3-benzoxazole-4-carboxylic acid (A23187) or ionomycin. 3) FFA triggered a rise in intracellular Ca(2+), which was abolished by cyclosporine, a blocker of mitochondrial permeability transition pore. Cyclosporine also abolished FFA-induced activation of AMPK. 4) Inhibition of Ca(2+)/calmodulin-dependent kinase kinase β (CaMKKβ) with 7-oxo-7H-benzimidazo[2,1-a]benz[de]isoquinoline-3-carboxylic acid acetate (STO-609) or down-regulation of CaMKKβ with short interfering RNA largely abrogated FFA-induced activation of AMPK. 5) FFA significantly suppressed nuclear factor-κB activity and inducible nitric-oxide synthase expression triggered by interleukin-1β and tumor necrosis factor α. This suppression was also largely abrogated by STO-609. Taken together, we conclude that FFA induces AMPK activation through the Ca(2+)-CaMKKβ pathway

Validation of a liquid chromatography-electrospray ionization tandem mass spectrometric method to determine six polyether ionophores in raw, UHT, pasteurized and powdered milk.

Science.gov (United States)

Pereira, Mararlene Ulberg; Spisso, Bernardete Ferraz; Jacob, Silvana do Couto; Monteiro, Mychelle Alves; Ferreira, Rosana Gomes; Carlos, Betânia de Souza; da Nóbrega, Armi Wanderley

2016-04-01

This study aimed to validate a method developed for the determination of six antibiotics from the polyether ionophore class (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) at residue levels in raw, UHT, pasteurized and powdered milk using QuEChERS extraction and high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The validation was conducted under an in-house laboratory protocol that is primarily based on 2002/657/EC Decision, but takes in account the variability of matrix sources. Overall recoveries between 93% and 113% with relative standard deviations up to 16% were obtained under intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit for monensin and 25% the Maximum Levels for all other substances. The method showed to be simple, fast and suitable for verifying the compliance of raw and processed milk samples regarding the limits recommended by Codex Alimentarius and those adopted in European Community for polyether ionophores. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of ionophore sensitivity of Eimeria acervulina and Eimeria maxima isolated from the Algerian Jijel province poultry farms

Science.gov (United States)

The present study represents the first description of ionophore resistance in Eimeria recovered from commercial Algerian (Jijel-Algeria) broiler farms. Microscopy and ITS1 PCR revealed only 2 Eimeria species present in litter from these farms- namely E. acervulina and E. maxima. A pool of these is...

Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction

DEFF Research Database (Denmark)

Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk

2013-01-01

A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid...... chromatography coupled to tandem mass spectrometry applying electrospray ionisation for detection. The samples were freeze-dried prior to extraction. The absolute recoveries for soil and sediment ranged from 71 to 123% (relative standard deviation (RSDs) below 16%) and in the range 94-133% (RSDs 9...

Effect of the dimetilsulfoxido in the response chemiluminescent and the consumption of oxygen of neutrophils activated human

International Nuclear Information System (INIS)

Garcia, J.

2001-01-01

Dimethylsulfoxide (DMSO), a hydroxyl radical scavenger, exerted a dose dependent inhibition on the luminol and lucigenin-enhanced chemiluminescent responses of human neutrophils activated with soluble and particulate stimulants. DMSO inhibition of the luminol chemiluminescense induced by calcium ionophore A23187 was probably due to OH scavenging, whereas inhibition of the lucigenin chemiluminescence suggested DMSO negatively affects the NADPH-dependent membrane oxidase of neutrophils. In agreement with this, DMSO moderately inhibited O2 consumption in PMN suspensions stimulated with chemotactic peptide and opsonized zymosan-induced luminol chemiluminescense was observed only when added before or in conjunction with stimulants, whereas A23187-induced chemiluminescense was inhibited by DMSO regardless of time of addition. Washing of DMSO-treated PMN resulted in increased luminol enhanced chemiluminescense in response to chemotactic peptide and opsonized zymosan. This is consistent with the idea that DMSO may be interfering with activation of the membrane subunits of the oxidase by translocation and docking of the cytoplasmic, regulatory subunits. These data imply that DMSO inhibits neutrophil chemiluminescense both by OH scavenging and interfering with oxidase activation. Key words:Dimethylsulfoxide, chemiluminescent, luminol, lucigenin,neutrophils [es

Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

Energy Technology Data Exchange (ETDEWEB)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha [Indian Institute of Technology-Roorkee, Department of Chemistry, Roorkee (India)

2008-04-15

A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-{alpha}-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10{sup -7}-1.0 x 10{sup -2} M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10{sup -8} M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb{sup 3+} ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

International Nuclear Information System (INIS)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha

2008-01-01

A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-α-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10 -7 -1.0 x 10 -2 M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10 -8 M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb 3+ ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

Release of leukotriene C4 from human polymorphonuclear leucocytes as determined by radioimmunoassay

International Nuclear Information System (INIS)

Aehringhaus, U.; Woelbling, R.H.; Peskar, B.M.; Peskar, B.A.; Koenig, W.; Patrono, C.

1982-01-01

Rabbits were immunized with a conjugate of leukotriene (LT)C 4 and bovine serum albumin prepared by coupling the single free amino group of the hapten to the protein using gluteraldehyde. Binding of [ 3 H]LTC 4 to the antibodies obtained is inhibited by 50% with 1.5 ng LTC 4 . The relative cross-section of LTD 4 is 16% and of LTC 4 -methyl ester 3.6%. The validity of the radioimmunoassay was demonstrated by comparison with bioassay using the isolated guinea pig ileum. Using the radioimmunoassay it could be shown that endogenous LTC 4 is released in a dose-dependent manner by human polymorphonuclear leucocytes stimulated with the divalent cation ionophore A23187. (Auth.)

Regulation of atrial natriuretic peptide (ANP) secretion

International Nuclear Information System (INIS)

Ruskoaho, H.; Toth, M.; Lang, R.E.; Unger, Th.; Garten, D.

1986-01-01

To investigate the role of calcium, protein kinase C and adenylate cyclase in the ANP secretion, the secretory responses from isolated perfused rat hearts to a calcium channel activator, Bay k8644 (methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluomethylphenyl)-2-pyridine-5-carboxylate), the calcium ionophore (A23187), the phorbol ester (12-0-tetradecanoylphorbol-13-acetate, TPA), and to forskolin were studied. ANP in perfusate was measured by radioimmunoassay 10 min before and during the infusion (30 min) of various agents at 2 min intervals. A23187 (5.7 x 10 -7 ) induced a sharp increase, whereas TPA (0.15 - 1.6 x 10 -7 ) caused a slowly progressive increase in ANP secretion. 4a-phorbol-12,13-didecanoate, a non-active phorbol ester, had no effect on ANP secretion. Bay k8644 (4 x 10 -7 ) and forskolin (1 x 10 -6 ) alone caused small but sustained increase in ANP secretion. The combination of TPA with Bay k8644, forskolin or A23187 stimulated ANP secretion higher than the calculated additive value for each agent. Dibuturyl-cAMP (1.6 x 10 -4 ) pretreatment also enhanced TPA-induced ANP release. 8-Bromo-cGMP (1.3 x 10 -4 ) and sodium nitroprusside (9 x 10 -5 ) alone had no effect, but both attenuated the TPA-induced ANP secretion. The results suggest that atrial cardiocytes possess at least two different secretory pathways for ANP secretion, which are probably dependent on protein kinase C and cyclic AMP

Radiation-induced changes in production of prostaglandins Fsub(2α), E, and thromboxane B2 in guinea pig parenchymal lung tissues

International Nuclear Information System (INIS)

Steel, L.K.; Catravas, G.N.

1982-01-01

At 1 hour to 4 days after unilateral exposure of guinea pigs to a single dose (0.5, 1.5, or 3.0 Gy) of gamma-radiation, changes were detected in prostaglandin and thromboxane concentrations in parenchymal lung tissues. At 1-3 hours after exposure, tissue levels of PGFsub(2α), PGE, and thromboxane B 2 were significantly elevated in animals receiving 3.0 Gy, with the magnitude of alteration revealing a radiation dose effect. By 24 hours, tissue prostaglandin and thromboxane levels returned to near control values. Lung tissue synthesis of prostaglandins in response to H-1 receptor stimulation by the exogenous addition of histamine revealed similar radiation dose effects. The carboxylic acid ionophore A23187, exogenously applied to lung tissues, revealed a transient peak of increased sensitivity to ionophore stimulation for TxB 2 synthesis at 24 hours and for PGFsub(2α) at 72 hours post-irradiation. The data suggest that significant alterations in prostaglandin and thromboxane concentrations in parenchymal lung tissues occur following irradiation, in a dose-dependent manner, and that altered responsiveness to H-1 receptor stimulation and divalent cation transport also occur

Radiation-induced changes in production of prostaglandins Fsub(2. cap alpha. ), E, and thromboxane B/sub 2/ in guinea pig parenchymal lung tissues

Energy Technology Data Exchange (ETDEWEB)

Steel, L K; Catravas, G N [Armed Forces Radiobiology Research Inst., Bethesda, MD (USA)

1982-11-01

At 1 hour to 4 days after unilateral exposure of guinea pigs to a single dose (0.5, 1.5, or 3.0 Gy) of gamma-radiation, changes were detected in prostaglandin and thromboxane concentrations in parenchymal lung tissues. At 1-3 hours after exposure, tissue levels of PGFsub(2..cap alpha..), PGE, and thromboxane B/sub 2/ were significantly elevated in animals receiving 3.0 Gy, with the magnitude of alteration revealing a radiation dose effect. By 24 hours, tissue prostaglandin and thromboxane levels returned to near control values. Lung tissue synthesis of prostaglandins in response to H-1 receptor stimulation by the exogenous addition of histamine revealed similar radiation dose effects. The carboxylic acid ionophore A23187, exogenously applied to lung tissues, revealed a transient peak of increased sensitivity to ionophore stimulation for TxB/sub 2/ synthesis at 24 hours and for PGFsub(2..cap alpha..) at 72 hours post-irradiation. The data suggest that significant alterations in prostaglandin and thromboxane concentrations in parenchymal lung tissues occur following irradiation, in a dose-dependent manner, and that altered responsiveness to H-1 receptor stimulation and divalent cation transport also occur.

Determination of ionophore antibiotics nactins produced by fecal Streptomyces from sheep.

Science.gov (United States)

Wang, Jun; Tan, Hongming; Lu, Yu; Cao, Lixiang

2014-04-01

To investigate the correlation between fecal actinobacteria and host animals, Streptomyces was isolated from fresh faeces of healthy sheep and secondary metabolites were analyzed. The most frequently isolated strain S161 with antibiotic activity against bacteria and fungi were analyzed. The S161 showed the highest 99 % similarity to Streptomyces canus DSB17 based on the 16S rRNA gene sequence analysis. Metabolite analysis based on MS and NMR spectra showed that S161 produces nactins, cyclotetralactones derived from nonactic acid and homononactic acid as building units of ionophoretic character. Due to ionophores are antimicrobial compounds that are commonly fed to ruminant animals to improve feed efficiency, stable beneficial interactions between Streptomyces bacteria and vertebrates have been demonstrated.

Pronuclear formation by ICSI using chemically activated ovine oocytes and zona pellucida bound sperm

Directory of Open Access Journals (Sweden)

J. E. Hernández-Pichardo

2016-11-01

Full Text Available Abstract Background In order to improve ICSI, appropiate sperm selection and oocyte activation is necessary. The objective of the present study was to determine the efficiency of fertilization using ICSI with chemically activated ovine oocytes and sperm selected by swim up (SU or swim up + zona pellucida (SU + ZP binding. Results Experiment 1, 4–20 replicates with total 821 in vitro matured oocytes were chemically activated with ethanol, calcium ionophore or ionomycin, to determine oocyte activation (precense of one PN. Treatments showed similar results (54, 47, 42 %, respectively but statistically differents (P  0.05. Conclusions Chemical activation induces higher ovine oocyte activation than mechanical activation. Ethanol slightly displays higher oocyte activation than calcium ionophore and ionomicine. Sperm selection with SU + ZP increased AR/A and AR/D rates in comparison with SU in fresh and frozen-thawed sperm. According to this, in terms of fertilization rates, chemical activation after ICSI increased oocyte PN formation compared to mechanical activation. Also, fresh sperm treated with SU and SU + ZP were significantly different than frozen-thawed sperm, but between sperm treatments no significant differences were obtained.

RSK2-induced stress tolerance enhances cell survival signals mediated by inhibition of GSK3β activity

International Nuclear Information System (INIS)

Lee, Cheol-Jung; Lee, Mee-Hyun; Lee, Ji-Young; Song, Ji Hong; Lee, Hye Suk; Cho, Yong-Yeon

2013-01-01

Highlights: •We demonstrated a novel function of RSK2 in stress tolerance. •RSK2 deficiency enhanced apoptosis by calcium stress. •RSK2-mediated GSK3β phosphorylation at serine 9 increased calcium-induced stress tolerance. •Calcium stress-induced apoptosis inhibited by adding back of RSK2 into RSK2 −/− MEFs. -- Abstract: Our previous studies demonstrated that RSK2 plays a key role in cell proliferation and transformation induced by tumor promoters such as epidermal growth factor (EGF) in mouse and human skin cells. However, no direct evidence has been found regarding the relationship of RSK2 and cell survival. In this study, we found that RSK2 interacted and phosphorylated GSK3β at Ser9. Notably, GSK3β phosphorylation at Ser9 was suppressed in RSK2 −/− MEFs compared with RSK2 +/+ MEFs by stimulation of EGF and calcium ionophore A23187, a cellular calcium stressor. In proliferation, we found that RSK2 deficiency suppressed cell proliferation compared with RSK2 +/+ MEFs. In contrast, GSK3β −/− MEFs induced the cell proliferation compared with GSK3β +/+ MEFs. Importantly, RSK2 −/− MEFs were induced severe cellular morphology change by A23187 and enhanced G1/G0 and sub-G1 accumulation of the cell cycle phase compared with RSK2 +/+ MEFs. The sub-G1 induction in RSK2 −/− MEFs by A23187 was correlated with increase of cytochrome c release, caspase-3 cleavage and apoptotic DNA fragmentation compared with RSK2 +/+ MEFs. Notably, return back of RSK2 into RSK2 −/− MEFs restored A23187-induced morphological change, and decreased apoptosis, apoptotic DNA fragmentation and caspase-3 induction compared with RSK2 −/− /mock MEFs. Taken together, our results demonstrated that RSK2 plays an important role in stress-tolerance and cell survival, resulting in cell proliferation and cancer development

Protein synthesis in muscle cultures from patients with duchenne muscular dystrophy

International Nuclear Information System (INIS)

Ionasescu, V.; Zellweger, H.; Ionasescu, R.; Lara-Braud, C.; Cancilla, P.A.

1976-01-01

Muscle samples for cultures were obtained from the quadriceps by open biopsy under local anesthesia in five patients with early stage of Duchenne muscular dystrophy (DMD) and 10 controls. Primary cultures were grown in Eagle's Minimum Essential Medium (MEM) with 20 per cent fetal calf serum. After 4 weeks, cells were trypsinized, counted, subcultured for 5 days in MEM with 5 per cent horse serum and finally incubated for 4 h with ( 3 H) leucine. Total protein synthesis showed a significant decrease (ALF OF CONTROL VALUES) only in muscle cultures from patients with DMD. Addition of calcium chloride alone or with A23187 ionophore normalized this defect in protein synthesis. By contrast, myosin heavy chain synthesis was measured and found normal in all patients. (author)

Pyrethroid insecticides and radioligand displacement from the GABA receptor chloride ionophore complex

International Nuclear Information System (INIS)

Crofton, K.M.; Reiter, L.W.; Mailman, R.B.

1987-01-01

Radioligand binding displacement studies were conducted to determine the effects of Type I and II pyrethroids on 3 H-flunitrazepam (FLU), 3 H-muscimol (MUS), and ( 35 S-t-butylbicyclophosphorothionate (TBPS) binding. Competition experiments with 3 H-FLU and 3 H-MUS indicate a lack of competition for binding by the pyrethroids. Type I pyrethroids failed to compete for the binding of ( 35 S-TBPS at concentrations as high as 50 pM. Type II pyrethroids inhibited ( 35 S-TBPS binding to rat brain synaptosomes with Ki values ranging from 5-10 pM. The data presented suggest that the interaction of Type II pyrethroids with the GABA receptor-ionophore complex is restricted to a site near the TBPS/picrotoxinin binding site

Mitochondrial respiration is sensitive to cytoarchitectural breakdown.

Science.gov (United States)

Kandel, Judith; Angelin, Alessia A; Wallace, Douglas C; Eckmann, David M

2016-11-07

An abundance of research suggests that cellular mitochondrial and cytoskeletal disruption are related, but few studies have directly investigated causative connections between the two. We previously demonstrated that inhibiting microtubule and microfilament polymerization affects mitochondrial motility on the whole-cell level in fibroblasts. Since mitochondrial motility can be indicative of mitochondrial function, we now further characterize the effects of these cytoskeletal inhibitors on mitochondrial potential, morphology and respiration. We found that although they did not reduce mitochondrial inner membrane potential, cytoskeletal toxins induced significant decreases in basal mitochondrial respiration. In some cases, basal respiration was only affected after cells were pretreated with the calcium ionophore A23187 in order to stress mitochondrial function. In most cases, mitochondrial morphology remained unaffected, but extreme microfilament depolymerization or combined intermediate doses of microtubule and microfilament toxins resulted in decreased mitochondrial lengths. Interestingly, these two particular exposures did not affect mitochondrial respiration in cells not sensitized with A23187, indicating an interplay between mitochondrial morphology and respiration. In all cases, inducing maximal respiration diminished differences between control and experimental groups, suggesting that reduced basal respiration originates as a largely elective rather than pathological symptom of cytoskeletal impairment. However, viability experiments suggest that even this type of respiration decrease may be associated with cell death.

Biphasic effect of oxygen radicals on prostaglandin production by rat mesangial cells

International Nuclear Information System (INIS)

Adler, S.; Stahl, R.A.K.; Baker, P.J.; Chen, Y.P.; Pritzl, P.M.; Couser, W.G.

1987-01-01

Cultured rat mesangial cells were exposed to a reactive oxygen species (ROS) generating system (xanthine plus xanthine oxidase) to explore the effect of ROS on their metabolism of arachidonic acid (AA). Cell viability, as assessed by 51 Cr release, was not affected by the concentrations of xanthine plus xanthine oxidase used. Prostaglandin E 2 (PGE 2 ) production following exposure to increasing quantities of xanthine plus xanthine oxidase was significantly decreased when cells were stimulated with the calcium ionophore A23187 or AA. Maximum suppression of production was seen within 10 min of ROS exposure. Thromboxane B 2 production was similarly decreased. This effect was reversed by addition of catalase to the ROS generating system but not by superoxide dismutase or mannitol, which suggested that H 2 O 2 was the responsible metabolite. High levels of H 2 O 2 suppressed PGE 2 production. Lower levels of H 2 O 2 resulted in significant stimulation of base-line PGE 2 production. Analysis of release of 3 H]AA-labeled metabolites from A23187-stimulated cells showed no effect of H 2 O 2 on phospholipase activity. Thus ROS can stimulate or inhibitor AA metabolism in the glomerular mesangium, which may have important effects on glomerular hemodynamics during glomerular injury

Synthesis and release of luteinizing hormone in vitro: manipulations of Ca2+ environment

International Nuclear Information System (INIS)

Liu, T.C.; Jackson, G.L.

1985-01-01

The authors determined if luteinizing hormone (LH) synthesis is Ca2+ dependent and coupled to LH release. They monitored LH synthesis when LH release was stimulated either by specific [gonadotropin-releasing hormone (GnRH)] or nonspecific stimuli (50 mM K+ and 2 or 20 microM Ca2+ ionophore A23187) and inhibited by Ca2+-reduced medium. LH synthesis was estimated by measuring incorporation of [ 3 H]glucosamine (glycosylation) and [ 14 C]alanine (translation) into total (cell and medium) immunoprecipitable LH by cultured rat anterior pituitary cells. Both GnRH (1 nM) and 50 mM K+ significantly stimulated LH release and glycosylation, but had no effect on LH translation. A23187 also stimulated LH release, but significantly depressed glycosylation of LH and total protein and [ 14 C]alanine uptake. Deletion of Ca2+ from the medium depressed both GnRH-induced LH release and glycosylation. Addition of 0.1 mM EGTA to Ca2+-free medium not only inhibited GnRH-induced release and glycosylation of LH but also uptake of precursors and glycosylation and translation of total protein. Thus, glycosylation and release of LH are Ca2+ dependent. Whether parallel changes in LH release and glycosylation reflect a cause and effect relationship remains to be determined

Selective sensing of mercury(II) using PVC-based membranes incorporating recently synthesized 1,3-alternate thiacalix[4]crown ionophore.

Science.gov (United States)

Mahajan, Rakesh Kumar; Kamal, Ajar; Kumar, Naresh; Bhalla, Vandana; Kumar, Manoj

2013-05-01

The construction and electrodes characteristics of poly(vinylchloride) (PVC)-based polymeric membrane electrode (PME) and coated graphite electrode (CGE), incorporating 1,3-alternate thiacalix[4]crown as ionophore for estimation of Hg(II) ions, are reported here. The best potential response was observed for PME-1 having membrane composition of: ionophore (6.2 mg), PVC (100.0 mg), 2-nitrophenyl octyl ether (2-NPOE; 200.0 mg), and sodium tetraphenyl borate (NaTPB; 2.0 mg); for CGE-1 with the membrane composition: ionophore (3.5 mg), PVC (40.0 mg), 2-NPOE (80.0 mg), and NaTPB (2.0 mg). The electrodes exhibits Nernstian slope of 29.16 mV/decade with PME-1 and 30.39 mV/decade with CGE-1 for Hg(II) ions over wide concentration range, i.e., 1.0 × 10(-1) to 5.0 × 10(-6) M with PME-1 and 1.0 × 10(-1) to 5.0 × 10(-7) M with CGE-1. Lower detection limits were found to be 9.77 × 10(-6) M for PME-1 and 7.76 × 10(-7) M for CGE-1 with response time varying from 10 to 20 s. Also, these electrodes work within pH range of 2.0-6.0 for PME-1 and 1.5-6.5 for CGE-1. Overall, CGE-1 has been found to be better than PME-1. CGE-1 has been used as indicator electrode for the potentiometric titration of Hg(II) ions with EDTA as well as successfully applied for determination of Hg(II) content in wastewater, insecticide, dental amalgam, and ayurvedic medicines samples with very good performance (0.9974 correlation coefficient in the comparison against volumetric method).

One-pot synthesis and antiproliferative activity of novel double-modified derivatives of the polyether ionophore monensin A.

Science.gov (United States)

Klejborowska, Greta; Maj, Ewa; Wietrzyk, Joanna; Stefańska, Joanna; Huczyński, Adam

2018-05-02

Monensin A (MON) is a polyether ionophore antibiotic, which shows a wide spectrum of biological activity. New MON derivatives such as double-modified ester-carbonates and double-modified amide-carbonates were obtained by a new and efficient one-pot synthesis with triphosgene as the activating reagent and the respective alcohol or amine. All new derivatives were tested for their antiproliferative activity against two drug-sensitive (MES-SA, LoVo) and two drug-resistant (MES-SA/DX5, LoVo/DX) cancer cell lines, and were also studied for their antimicrobial activity against different Staphylococcus aureus and Staphylococcus epidermidis bacterial strains. For the first time, the activity of MON and its derivatives against MES-SA and MES-SA/DX5 were evaluated. © 2018 John Wiley & Sons A/S.

The Determination of Six Ionophore Coccidiostats in Feed by Liquid Chromatography with Postcolumn Derivatisation and Spectrofotometric/Fluorescence Detection

Directory of Open Access Journals (Sweden)

Małgorzata Olejnik

2013-01-01

Full Text Available The control of levels of anticoccidial feed additives in targeted feeds plays an important role in the assurance of efficiency of animal treatment, prevention of drug resistance, and food safety. The robust and labour-efficient method for the simultaneous determination of six ionophore coccidiostats (lasalocid, maduramicin, monensin, narasin, salinomycin, and semduramicin in targeted feed has been developed. Properly grinded and homogenized feed sample was spiked with internal standard (monesin methyl ester and extracted with methanol. The extract was analysed with reversed phase HPLC without any further purification. The separation of the analytes with conventional C18 and core-shell columns was compared. Lasalocid was analysed with fluorescence detection, whereas other ionophores were detected with UV-Vis detector after derivatisation with vanillin in the presence of sulfuric acid. Fortified samples and targeted feeds at authorized levels were used for method validation. Recovery was in the range of 85–110%, depending on the analyte. The within-laboratory reproducibility did not exceed the target value from Horwitz equation. The results of the proficiency tests (z-scores in the range of −1.0 to 1.9 confirmed the reliability of the developed protocol.

Cloning and expression of calmodulin gene in Scoparia dulcis.

Science.gov (United States)

Saitoh, Daisuke; Asakura, Yuki; Nkembo, Marguerite Kasidimoko; Shite, Masato; Sugiyama, Ryuji; Lee, Jung-Bum; Hayashi, Toshimitsu; Kurosaki, Fumiya

2007-06-01

A homology-based cloning strategy yielded a cDNA clone, designated Sd-cam, encoding calmodulin protein from Scoparia dulcis. The restriction digests of genomic DNA of S. dulcis showed a single hybridized signal when probed with the fragment of this gene in Southern blot analyses, suggesting that Sd-cam occurs as a sole gene encoding calmodulin in the plant. The reverse-transcription polymerase chain reaction analysis revealed that Sd-cam was appreciably expressed in leaf, root and stem tissues. It appeared that transcription of this gene increased transiently when the leaf cultures of S. dulcis were treated with methyl jasmonate and calcium ionophore A23187. These results suggest that transcriptional activation of Sd-cam is one of the early cellular events of the methyl jasmonate-induced responses of S. dulcis.

ATP-dependent calcium transport across basal plasma membranes of human placental trophoblast

International Nuclear Information System (INIS)

Fisher, G.J.; Kelley, L.K.; Smith, C.H.

1987-01-01

As a first step in understanding the cellular basis of maternal-fetal calcium transfer, the authors examined the characteristics of calcium uptake by a highly purified preparation of the syncytiotrophoblast basal (fetal facing) plasma membrane. In the presence of nanomolar concentrations of free calcium, basal membranes demonstrated substantial ATP-dependent calcium uptake. This uptake required magnesium, was not significantly affected by Na + or K + (50 mM), or sodium azide (10 mM). Intravesicular calcium was rapidly and completely released by the calcium ionophore rapidly and completely released by the calcium ionophore A23187. Calcium transport was significantly stimulated by the calcium-dependent regulatory protein calmodulin. Placental membrane fractions enriched in endoplasmic reticulum (ER) and mitochondria also demonstrated ATP-dependent calcium uptake. In contrast to basal membrane, mitochondrial calcium uptake was completely inhibited by azide. The rate of calcium uptake was completely inhibited by azide. The rate of calcium uptake by the ER was only 20% of that of basal membranes. They conclude that the placental basal plasma membrane possesses a high-affinity calcium transport system similar to that found in plasma membranes of a variety of cell types. This transporter is situated to permit it to function in vivo in maternal-fetal calcium transfer

Transcriptional activation of a geranylgeranyl diphosphate synthase gene, GGPPS2, isolated from Scoparia dulcis by treatment with methyl jasmonate and yeast extract.

Science.gov (United States)

Yamamura, Y; Mizuguchi, Y; Taura, F; Kurosaki, F

2014-10-01

A cDNA clone, designated SdGGPPS2, was isolated from young seedlings of Scoparia dulcis. The putative amino acid sequence of the translate of the gene showed high homology with geranylgeranyl diphosphate synthase (GGPPS) from various plant sources, and the N-terminal residues exhibited the characteristics of chloroplast targeting sequence. An appreciable increase in the transcriptional level of SdGGPPS2 was observed by exposure of the leaf tissues of S. dulcis to methyl jasmonate, yeast extract or Ca(2+) ionophore A23187. In contrast, SdGGPPS1, a homologous GGPPS gene of the plant, showed no or only negligible change in the expression level upon treatment with these stimuli. The truncated protein heterologously expressed in Escherichia coli in which the putative targeting domain was deleted catalyzed the condensation of farnesyl diphosphate and isopentenyl diphosphate to liberate geranylgeranyl diphosphate. These results suggested that SdGGPPS2 plays physiological roles in methyl jasmonate and yeast extract-induced metabolism in the chloroplast of S. dulcis cells.

Somatic cell cloning in Buffalo (Bubalus bubalis): effects of interspecies cytoplasmic recipients and activation procedures.

Science.gov (United States)

Kitiyanant, Y; Saikhun, J; Chaisalee, B; White, K L; Pavasuthipaisit, K

2001-01-01

Successful nuclear transfer (NT) of somatic cell nuclei from various mammalian species to enucleated bovine oocytes provides a universal cytoplast for NT in endangered or extinct species. Buffalo fetal fibroblasts were isolated from a day 40 fetus and were synchronized in presumptive G(0) by serum deprivation. Buffalo and bovine oocytes from abattoir ovaries were matured in vitro and enucleated at 22 h. In the first experiment, we compared the ability of buffalo and bovine oocyte cytoplasm to support in vitro development of NT embryos produced by buffalo fetal fibroblasts as donor nuclei. There were no significant differences (p > 0.05) between the NT embryos derived from buffalo and bovine oocytes, in fusion (74% versus 71%) and cleavage (77% versus 75%) rates, respectively. No significant differences were also observed in blastocyst development (39% versus 33%) and the mean cell numbers of day 7 cloned blastocysts (88.5 +/- 25.7 versus 51.7 +/- 5.4). In the second experiment, we evaluated the effects of activation with calcium ionophore A23187 on development of NT embryos after electrical fusion. A significantly higher (p cloned buffalo blastocysts similar to those transferred into buffalo oocytes. Calcium ionophore used in conjunction with 6-DMAP effectively induces NT embryo development.

PVC membrane based potentiometric sensor for uranyl ion using thenoyl trifluoro acetone as ionophore

International Nuclear Information System (INIS)

Nanda, D.; Chouhan, H.P.S.; Maiti, B.

2004-01-01

Uranyl ion selective electrode based on thenoyl trifluoro acetone (TTA) incorporated into a polyvinyl chloride (PVC) membrane has been developed where dibutyl phthalate and sodium tetraphenyl borate have been used as plasticizer and anion excluder respectively. The PVC membrane containing the active ionophore, TTA, and the other ingredients has been directly cast a graphite electrode. The electrode shows near Nernstian response to UO 2 2+ in the concentration range of 10 -1 to 10 -6 mol. L -1 an average slope of 30 mV/decade. Alkali and alkaline earth ions do not interfere with the determination of uranyl ion. Interference of transition metal ions and Th (IV) is eliminated using EDTA. (author)

Effects of Echium plantagineum L. Bee Pollen on Basophil Degranulation: Relationship with Metabolic Profile

Directory of Open Access Journals (Sweden)

Eduarda Moita

2014-07-01

Full Text Available This study aimed to evaluate the anti-allergic potential of Echium plantagineum L. bee pollen and to characterize its primary metabolites. The activity of E. plantagineum hydromethanolic extract, devoid of alkaloids, was tested against β-hexosaminidase release in rat basophilic leukemic cells (RBL-2H3. Two different stimuli were used: calcium ionophore A23187 and IgE/antigen. Lipoxygenase inhibitory activity was evaluated in a cell-free system using soybean lipoxygenase. Additionally, the extract was analysed by HPLC-UV for organic acids and by GC-IT/MS for fatty acids. In RBL-2H3 cells stimulated either with calcium ionophore or IgE/antigen, the hydromethanolic extract significantly decreased β-hexosaminidase release until the concentration of 2.08 mg/mL, without compromising cellular viability. No effect was found on lipoxygenase. Concerning extract composition, eight organic acids and five fatty acids were determined for the first time. Malonic acid (80% and α-linolenic acid (27% were the main compounds in each class. Overall, this study shows promising results, substantiating for the first time the utility of intake of E. plantagineum bee pollen to prevent allergy and ameliorate allergy symptoms, although a potentiation of an allergic response can occur, depending on the dose used.

Adenosine: a putative mediator of bronchoconstriction in asthma

Energy Technology Data Exchange (ETDEWEB)

Mann, J.S.

1987-01-01

The protective effect of a muscarinic cholinergic antagonists, ipratropium bromide (IB) from inhaled adenosine- and methacholine-induced bronchoconstriction in asthma was studied. Inhaled IB protected from methacholine- but not adenosine-induced bronchoconstriction. Parasympathetically mediated bronchoconstriction is therefore unlikely to account for adenosine's airway effect in asthma. The capacity of theophylline, a bronchodilator and a competitive antagonist of adenosine at its cell surface receptors, to protect asthmatic subjects from adenosine- and histamine-induced bronchoconstriction was determined. Asthmatic airways are infiltrated with inflammatory cells. Human leucocytes prelabeled with (/sup 3/H)-adenine when activated with the calcium ionophore A23187 released labelled hypoxanthine, inosine and adenosine which was associated with a dose-related release of histamine. The chemotactic peptide f-MLP while inducing histamine release had an inconstant effect on release of label. In four of five experiments f-MLP produced a transient early increase in label release but in the remaining experiment no significant release was observed. Anti-human IgE failed to induce significant label release despite releasing histamine. Activated leucocytes are therefore a potential source of adenosine in asthma.

Myoglobin-biomimetic electroactive materials made by surface molecular imprinting on silica beads and their use as ionophores in polymeric membranes for potentiometric transduction.

Science.gov (United States)

Moreira, Felismina T C; Dutra, Rosa A F; Noronha, Joao P C; Sales, M Goreti F

2011-08-15

Myoglobin (Mb) is among the cardiac biomarkers playing a major role in urgent diagnosis of cardiovascular diseases. Its monitoring in point-of-care is therefore fundamental. Pursuing this goal, a novel biomimetic ionophore for the potentiometric transduction of Mb is presented. It was synthesized by surface molecular imprinting (SMI) with the purpose of developing highly efficient sensor layers for near-stereochemical recognition of Mb. The template (Mb) was imprinted on a silane surface that was covalently attached to silica beads by means of self-assembled monolayers. First the silica was modified with an external layer of aldehyde groups. Then, Mb was attached by reaction with its amine groups (on the external surface) and subsequent formation of imine bonds. The vacant places surrounding Mb were filled by polymerization of the silane monomers 3-aminopropyltrimethoxysilane (APTMS) and propyltrimethoxysilane (PTMS). Finally, the template was removed by imine cleavage after treatment with oxalic acid. The results materials were finely dispersed in plasticized PVC selective membranes and used as ionophores in potentiometric transduction. The best analytical features were found in HEPES buffer of pH 4. Under this condition, the limits of detection were of 1.3 × 10(-6)mol/L for a linear response after 8.0 × 10(-7) mol/L with an anionic slope of -65.9 mV/decade. The imprinting effect was tested by preparing non-imprinted (NI) particles and employing these materials as ionophores. The resulting membranes showed no ability to detect Mb. Good selectivity was observed towards creatinine, sacarose, fructose, galactose, sodium glutamate, and alanine. The analytical application was conducted successfully and showed accurate and precise results. Copyright © 2011 Elsevier B.V. All rights reserved.

Quantitative proteomic studies in resistance mechanisms of Eimeria tenella against polyether ionophores.

Science.gov (United States)

Thabet, Ahmed; Honscha, Walther; Daugschies, Arwid; Bangoura, Berit

2017-05-01

Polyether ionophores are widely used to treat and control coccidiosis in chickens. Widespread use of anticoccidials resulted in worldwide resistance. Mechanisms of resistance development and expansion are complex and poorly understood. Relative proteomic quantification using LC-MS/MS was used to compare sensitive reference strains (Ref-1, Ref-2) with putatively resistant and moderately sensitive field strains (FS-R, FS-mS) of Eimeria tenella after isotopic labelling with tandem mass tags (TMT). Ninety-seven proteins were identified, and 25 of them were regulated. Actin was significantly upregulated in resistant strains in comparison with their sensitive counterparts. On the other hand, microneme protein (MIC4) was downregulated in resistant strains. Optimization of labelling E. tenella sporozoites by TMT might identify further proteins that play a role in the obvious complex mechanism leading to resistance against Monensin.

Trace Level Determination of Polyether Ionophores in Feed

Science.gov (United States)

Rokka, Mervi; Jestoi, Marika; Peltonen, Kimmo

2013-01-01

A liquid chromatography-mass spectrometric method was developed and validated to determine six polyether ionophores (lasalocid sodium, monensin sodium, salinomycin sodium, narasin, maduramicin ammonium alpha, and semduramicin sodium) in feed samples. The method developed was very straightforward, involving extraction with 84% acetonitrile of the coccidiostats from the feed samples and filtration of the raw extract prior to chromatographic analysis. Method validation included the determination of selectivity, linearity, specificity, repeatability, the limit of detection, limit of quantification, decision limit (CCα), detection capability (CCβ), and recovery. Feed samples from the Finnish national feed control programme and suspected carry-over samples from a feed manufacturer were analysed in parallel with an existing liquid chromatography method coupled with ultraviolet detection. All feed control samples were negative in LC-UV, but with the developed MS method, monensin, salinomycin, and narasin were detected at concentrations of <0.025–0.73 mg/kg, <0.025–0.027 mg/kg, and <0.025–1.6 mg/kg, respectively. In suspected carry-over samples after an output of 2.0 tonnes of unmedicated feed in the pelletizer line, the concentrations of monensin, salinomycin, and narasin varied from undetected to 16 mg/kg. In the mixer line, after 3.2 tonnes of unmedicated feed output, the concentrations of monensin, salinomycin, and narasin varied from undetected to 2.4 mg/kg. PMID:23484082

Co-induction of glucose regulated proteins and adriamycin resistance in Chinese hamster cells

International Nuclear Information System (INIS)

Shen, J.; Hughes, C.; Cai, J.; Bartels, C.; Gessner, T.; Subjeck, J.

1987-01-01

Glucose deprivation, anoxia, calcium ionophore A23187 or 2-deoxyglucose all inducers of glucose regulated proteins (grps), also lead to a significant induction of resistance to the drug adriamycin. In the case of anoxia, A23187 and 2-deoxyglucose, the induction of resistance correlates with both the application of the inducing stress and the induction of grps. In the case of glucose deprivation, the onset of resistance correlates with the onset of glucose deprivation and precedes grp induction. Removal of each grp including condition results in the rapid disappearance of this resistance in a manner which correlates with the repression of the grps. This drug resistance can be induced in confluent cells or in actively proliferating cells, although the effect is greater in the more sensitive proliferating cells. Induction of heat shock proteins (hsps) does not appear to lead to any major change in adriamycin resistance. Grp induced cells retain less adriamycin than do controls with the greatest reduction occurring during anoxia, which is also the strongest inducer of grps and resistance. The authors propose that the application of a grp inducing stress leads to a concurrent induction in drug resistance, possibly via the translocation of grps in the cell. Finally, they also observed that adriamycin itself can induce both hsps and grps. It is possible that adriamycin exposure may correspondingly induce auto-resistance

Potentiometric polymeric membrane electrodes for mercury detection using calixarene ionophores.

Science.gov (United States)

Tyagi, Sonika; Agarwal, Himanshu; Ikram, Saiqa

2010-01-01

It is here established that potentiometric polymeric membrane electrodes based on electrically neutral ionophores are a useful analytical tool for the detection of heavy metal ions from environmental and industrial waste water. PVC based membrane containing p-tert-butyl-calix[4]arenethioether derivative as active material along with sodiumtetraphenylborate (NaTPB) as solvent mediator and dibutylphthalate as a plasticizer in the ratio 45:9:460:310 (w/w%) (I:NaTPB:DBP:PVC) exhibits good properties with a Nernstian response of 29.50+/-1.0 mV per decade of activity and a working concentration range of 7.2 x 10(-8)-1.0 x 10(-1) M. The electrode gave more stable potential readings when used around pH 2.5-6.8 and exhibits fast response time of 14 s. The sensors were found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of acetone, methanol or ethanol and could be used over a period of 7-9 months. Excellent selectivity for Hg(2+) ions is indicated by match potential method and fixed interference method. The sensors could be used successfully in the estimation of mercury in different sample.

Protein phosphorylation in isolated hepatocytes of septic and endotoxemic rats

International Nuclear Information System (INIS)

Deaciuc, I.V.; Spitzer, J.A.

1989-01-01

The purpose of this study was to investigate possible alterations induced by sepsis and endotoxicosis in the late phase of Ca2+-dependent signaling in rat liver. Hepatocytes isolated from septic or chronically endotoxin (ET)-treated rats were labeled with [32P]H3PO4 and stimulated with various agents. Proteins were resolved by one-dimensional polyacrylamide gel electrophoresis and autoradiographed. Vasopressin (VP)- and phenylephrine (PE)-induced responses were attenuated in both septic and ET-treated rats for cytosolic and membrane proteins compared with their respective controls. Glucagon and 12-O-myristate phorbol-13-acetate (TPA) affected only the phosphorylation of membrane proteins. Glucagon-induced changes in the phosphorylation of membrane proteins were affected by both sepsis and endotoxicosis, whereas TPA-stimulated phosphorylation was lowered only in endotoxicosis. Response to the Ca2+ ionophore A23187 was depressed in septic rats for cytosolic proteins. The phosphorylation of two cytosolic proteins, i.e., 93 and 61 kDa (previously identified as glycogen phosphorylase and pyruvate kinase, respectively), in response to VP, PE, and A23187 was severely impaired by endotoxicosis and sepsis. TPA did not affect the phosphorylation state of these two proteins. The results show that sepsis and endotoxicosis produce perturbations of the phosphorylation step in Ca2+ transmembrane signaling. Such changes can explain alterations of glycogenolysis and gluconeogenesis associated with sepsis and endotoxicosis

Combinatorial screening of potentiometric Pb(II) sensors from polysulfoaminoanthraquinone solid ionophore.

Science.gov (United States)

Huang, Mei-Rong; Ding, Yong-Bo; Li, Xin-Gui

2014-03-10

A potentiometric Pb(II)-selective sensor was fabricated by a combinatorial screening of electrically conducting polysulfoaminoanthraquinone (PSA) nanoparticles as a solid ionophore, ion exchangers (oleic acid (OA) and NaTPB), plasticizers in a polyvinyl chloride (PVC) matrix, membrane thickness, inner filling ion species, and concentration. The membrane sensor with the composition of PSA/PVC/DOP (dioctyl phthalate)/OA (1.0:33:61:5.0) exhibited the best performance, including a slope of 29.3 mV decade(-1) in the concentration range 10(-6.3)-10(-1.6) M, detection limit of 1.6 × 10(-7) M, response time of 16 s, lifetime of five months, and good response reversibility. The proposed sensor has demonstrated good selectivity for Pb(II) over other monovalent, divalent and trivalent interfering ions, and could be used in a pH range of 3.62-5.22. The Pb(II) sensor has been successfully applied for the determination of Pb(II) concentration in real-world samples and also as an indicator electrode for potentiometric titration of lead ions.

Lactadherin inhibits secretory phospholipase A2 activity on pre-apoptotic leukemia cells.

Directory of Open Access Journals (Sweden)

Steffen Nyegaard

Full Text Available Secretory phospholipase A2 (sPLA2 is a critical component of insect and snake venoms and is secreted by mammalian leukocytes during inflammation. Elevated secretory PLA2 concentrations are associated with autoimmune diseases and septic shock. Many sPLA2's do not bind to plasma membranes of quiescent cells but bind and digest phospholipids on the membranes of stimulated or apoptotic cells. The capacity of these phospholipases to digest membranes of stimulated or apoptotic cells correlates to the exposure of phosphatidylserine. In the present study, the ability of the phosphatidyl-L-serine-binding protein, lactadherin to inhibit phospholipase enzyme activity has been assessed. Inhibition of human secretory phospholipase A2-V on phospholipid vesicles exceeded 90%, whereas inhibition of Naja mossambica sPLA2 plateaued at 50-60%. Lactadherin inhibited 45% of activity of Naja mossambica sPLA2 and >70% of human secretory phospholipase A2-V on the membranes of human NB4 leukemia cells treated with calcium ionophore A23187. The data indicate that lactadherin may decrease inflammation by inhibiting sPLA2.

Salinomycin Hydroxamic Acids: Synthesis, Structure, and Biological Activity of Polyether Ionophore Hybrids.

Science.gov (United States)

Borgström, Björn; Huang, Xiaoli; Chygorin, Eduard; Oredsson, Stina; Strand, Daniel

2016-06-09

The polyether ionophore salinomycin has recently gained attention due to its exceptional ability to selectively reduce the proportion of cancer stem cells within a number of cancer cell lines. Efficient single step strategies for the preparation of hydroxamic acid hybrids of this compound varying in N- and O-alkylation are presented. The parent hydroxamic acid, salinomycin-NHOH, forms both inclusion complexes and well-defined electroneutral complexes with potassium and sodium cations via 1,3-coordination by the hydroxamic acid moiety to the metal ion. A crystal structure of an cationic sodium complex with a noncoordinating anion corroborates this finding and, moreover, reveals a novel type of hydrogen bond network that stabilizes the head-to-tail conformation that encapsulates the cation analogously to the native structure. The hydroxamic acid derivatives display down to single digit micromolar activity against cancer cells but unlike salinomycin selective reduction of ALDH(+) cells, a phenotype associated with cancer stem cells was not observed. Mechanistic implications are discussed.

Polyether ionophores: broad-spectrum and promising biologically active molecules for the control of drug-resistant bacteria and parasites.

Science.gov (United States)

Kevin Ii, Dion A; Meujo, Damaris Af; Hamann, Mark T

2009-02-01

As multidrug-resistant (MDR) pathogens continue to emerge, there is a substantial amount of pressure to identify new drug candidates. Carboxyl polyethers, also referred to as polyether antibiotics, are a unique class of compounds with outstanding potency against a variety of critical infectious disease targets including protozoa, bacteria and viruses. The characteristics of these molecules that are of key interest are their selectivity and high potency against several MDR etiological agents. Although many studies have been published about carboxyl polyether antibiotics, there are no recent reviews of this class of drugs. The purpose of this review is to provide the reader with an overview of the spectrum of activity of polyether antibiotics, their mechanism of action, toxicity and potential as drug candidates to combat drug-resistant infectious diseases. Polyether ionophores show a high degree of promise for the potential control of drug-resistant bacterial and parasitic infections. Despite the long history of use of this class of drugs, very limited medicinal chemistry and drug optimization studies have been reported, thus leaving the door open to these opportunities in the future. Scifinder and PubMed were the main search engines used to locate articles relevant to the topic presented in the present review. Keywords used in our search were specific names of each of the 88 compounds presented in the review as well as more general terms such as polyethers, ionophores, carboxylic polyethers and polyether antibiotics.

Inhibition of basophil histamine release by gangliosides. Further studies on the significance of cell membrane sialic acid in the histamine release process

DEFF Research Database (Denmark)

Jensen, C; Norn, S; Thastrup, Ole

1987-01-01

with the glucolipid mixture increased the sialic acid content of the cells, and this increase was attributed to an insertion of gangliosides into the cell membrane. The inhibition of histamine release was abolished by increasing the calcium concentration, which substantiates our previous findings that cell membrane......Histamine release from human basophils was inhibited by preincubation of the cells with a glucolipid mixture containing sialic acid-containing gangliosides. This was true for histamine release induced by anti-IgE, Concanavalin A and the calcium ionophore A23187, whereas the release induced by S....... aureus Wood 46 was not affected. It was demonstrated that the inhibitory capacity of the glucolipid mixture could be attributed to the content of gangliosides, since no inhibition was obtained with cerebrosides or with gangliosides from which sialic acid was removed. Preincubation of the cells...

A new method to evaluate anti-allergic effect of food component by measuring leukotriene B4 from a mouse mast cell line.

Science.gov (United States)

Takasugi, Mikako; Muta, Emi; Yamada, Koji; Arai, Hirofumi

2018-02-01

Leukotrienes (LTs), chemical mediators produced by mast cells, play an important role in allergic symptoms such as food allergies and hay fever. We tried to construct an evaluation method for the anti-LTB 4 activity of chemical substances using a mast cell line, PB-3c. PB-3c pre-cultured with or without arachidonic acid (AA) was stimulated by calcium ionophore (A23187) for 20 min, and LTB 4 production by the cells was determined by HPLC with UV detection. LTB 4 was not detected when PB-3c was pre-cultured without AA. On the other hand, LTB 4 production by PB-3c pre-cultured with AA was detectable by HPLC, and the optimal conditions of PB-3c for LTB 4 detection were to utilize the cells pre-cultured with 50 µM AA for 48 h. MK-886 (5-lipoxygenase inhibitor) completely inhibited LTB 4 production, but AACOCF 3 (phospholipase A 2 inhibitor) slightly increased LTB 4 production, suggesting that LTB 4 was generated from exogenous free AA through 5-lipoxygenase pathway. We applied this technique to the evaluation of the anti-LTB 4 activity of food components. PB-3c pre-cultured with 50 µM AA for 48 h was stimulated with A23187 in the presence of 50 µM soybean isoflavones (daidzin, genistin, daidzein, and genistein), equol, quercetin, or kaempferol. Genistein, equol, quercetin, and kaempferol strongly inhibited LTB 4 production without cytotoxicity. These results suggest that a new assay system using PB-3c is convenient to evaluate LTB 4 inhibition activity by food components. This method could be utilized for elucidation of the mechanisms of LTB 4 release suppression by food components such as flavonoids and the structure-activity relationship.

Inhibition of release of inflammatory mediators in primary and cultured cells by a Chinese herbal medicine formula for allergic rhinitis

Directory of Open Access Journals (Sweden)

McPhee Sarah

2007-02-01

Full Text Available Abstract Background We demonstrated that a Chinese herbal formula, which we refer to as RCM-101, developed from a traditional Chinese medicine formula, reduced nasal and non-nasal symptoms of seasonal allergic rhinitis (SAR. The present study in primary and cultured cells was undertaken to investigate the effects of RCM-101 on the production/release of inflammatory mediators known to be involved in SAR. Methods Compound 48/80-induced histamine release was studied in rat peritoneal mast cells. Production of leukotriene B4 induced by the calcium ionophore A23187 was studied in porcine neutrophils using an HPLC assay and lipopolysaccharide-stimulated prostaglandin E2 production was studied in murine macrophage (Raw 264.7 cells by immune-enzyme assay. Expression of cyclooxygenase-1 (COX-1 and cyclooxygenase-2 (COX-2 was determined in Raw 264.7 cells, using western blotting techniques. Results RCM-101 (1–100 μg/mL produced concentration-dependent inhibition of compound 48/80-induced histamine release from rat peritoneal mast cells and of lipopolysaccharide-stimulated prostaglandin E2 release from Raw 264.7 cells. Over the range 1 – 10 μg/mL, it inhibited A23187-induced leukotriene B4 production in porcine neutrophils. In addition, RCM-101 (100 μg/mL inhibited the expression of COX-2 protein but did not affect that of COX-1. Conclusion The findings indicate that RCM-101 inhibits the release and/or synthesis of histamine, leukotriene B4 and prostaglandin E2 in cultured cells. These interactions of RCM-101 with multiple inflammatory mediators are likely to be related to its ability to reduce symptoms of allergic rhinitis.

The Novel SCN''- Ion-selective Electrode Based on the 1-Benzyl-3-(4-nitrophenyl) thio-urea Ionophore

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Mi; Kang, Dong Hyeon; Choe, Ju Eun; You, Jung Min; Go, Min Jeong; Lee, Jung Seong; Jeon, Seung Won [Chungnam National University, Daejeon (Korea, Republic of)

2014-09-15

A potentiometric sensor based on the 1-benzyl-3-(4-nitrophenyl) thio-urea was synthesized and tested as an ionophore in PVC based membrane sensor towards SCN - ions. This membrane exhibits a linear stable response over a wide concentration range (1.0 × 10''-5 to 1.0 × 10''-2 M) with a slope of -59.2 mV/dec., a detection limit of log[SCN''- ] = -5.05, and a selectivity coefficient for thiocyanate against perchlorate anion of logK{sub s}cn''pot = -0.133. The selectivity series of the membrane is as follows: SCN''- > ClO{sub 4}''- > I''- >NO{sub 3}''- >HSO{sub 3}''- > Cl''-HSO{sub '}'-''4 > F''- > CH{sub 3}COO''- > HCO''-''3 > Br''- > H{sub 2}PO{sub 4}''- > SO{sub 3}''-''2 > SO{sub 4}''-''2 > CO{sub 3}''-''2. The proposed electrode showed good selectivity and a good response for the SCN''- ion over a wide variety of other anions in pH 6.0 buffer solutions and has a fast response time of about < 5s.. The influences of the membrane by pH, ionophore, and plasticizer were studied.

A Pilot Study: Effects of Dietary Supplementation with α-Linolenic Acid-Enriched Perilla Seed Oil on Bronchial Asthma

Directory of Open Access Journals (Sweden)

Kozo Ashida

1997-01-01

Full Text Available N-3 fatty acids, such as fish oil, have been reported to have some beneficial effects in patients with bronchial asthma. The effects of dietary supplementation with perilla seed oil rich in a-linolenic acid (α-LNA, parent n-3 fatty acid, were studied in five patients with asthma. The symptoms of asthma and mean peak flow rates (PFR both early in the morning and in the evening were improved 2 weeks after dietary supplementation and the increases in PFR were significant (P<0.05. The generation of leukotriene B4 (LTB4 by peripheral leukocytes stimulated with the Ca2+ ionophore A23187 was significantly suppressed from 77.6 to 41.6 ng/5Xl06 cells by dietary supplementation (P<0.05. The generation of leukotriene C4 (LTC4 by leukocytes was also significantly suppressed from 64.0 to 38.8 ng/5x106 cells after supplementation with perilla seed oil (P<0.05. These results suggest that dietary supplementation with perilla seed oil is beneficial for the treatment of asthma.

Targeting microparticle biogenesis: a novel approach to the circumvention of cancer multidrug resistance.

Science.gov (United States)

Roseblade, Ariane; Luk, Frederick; Ung, Alison; Bebawy, Mary

2015-01-01

Microparticles (MPs) are released from most eukaryotic cells after the vesiculation of the plasma membrane and serve as vectors of long and short-range signaling. MPs derived from multidrug resistant (MDR) cancer cells carry molecular components of the donor cell such as nucleic acids and proteins, and can alter the activity of drug-sensitive recipient cells through the transfer of their cargo. Given the substantial role of MPs in the acquisition and dissemination of MDR, we propose that the inhibition of MP release provides a novel therapeutic approach. This study characterises the effect of a panel of molecules known to act on MP-biosynthetic pathways. We demonstrate a differential effect by these molecules on MP inhibition that appear dependent on the release of intracellular calcium stores following activation with the calcium ionophore A23187. Calpain inhibitor, PD-150606; a selective inhibitor of Rho-associated, coiled-coil containing protein kinase (ROCK), Y-27632; and the vitamin B5 derivative pantethine, inhibited MP release only upon prior activation with A23187. Calpain inhibitor II showed significant inhibition in the absence of cell activation, whereas the vitamin B5 derivatives cystamine dihydrochloride and cysteamine hydrochloride showed no effect on MP inhibition under either condition. In contrast the classical pharmacological inhibitor of MDR, the calcium channel blocker Verapamil, showed an increase in MP formation on resting cells. These results suggest a potential role for calcium in the mechanism of action for PD-150606, Y-27632 and pantethine. These molecules, together with calpain inhibitor II have shown promise as modulators of MP release and warrant consideration as potential candidates for the development of an alternative therapeutic strategy for the prevention of MP-mediated MDR in cancer.

Calcium ionophore A23187 specifically decreases the secretion of beta-secretase cleaved amyloid precursor protein during apoptosis in primary rat cortical cultures

DEFF Research Database (Denmark)

Sennvik, K; Benedikz, Eirikur; Fastbom, J

2001-01-01

Alzheimer's disease (AD) is characterized by the degeneration and loss of neurons, intracellular neurofibrillary tangles and the accumulation of extracellular senile plaques consisting mainly of beta-amyloid (A beta). A beta is generated from the amyloid precursor protein (APP) by sequential beta...

Thiopental and Phenytoin as Novel Ionophores for Potentiometric Determination of Lead (II Ions

Directory of Open Access Journals (Sweden)

Yasser M. Abd EL-Karem

2009-03-01

Full Text Available Two novel polymeric membrane sensors for the analysis of Pb(II have been developed based ontwo therapeutic drugs, thiopental (TP and phenytoin (PT as two new ionophores and potassium tetrakis(p-chlorophenyl borate (KTpClPB as a lipophilic additive, in plasticized PVC membranes. The sensors show a Nernstian response for Pb(II ions over the wide concentration ranges of 1×10-2 - 7×10-6 M and 1×10-2 - 8×10-6 M for the sensors based on thiopental and phenytoin, respectively. The proposed sensors have a fast response time and can be used for more than nine weeks without any considerable divergence in potentials. The sensors exhibit comparatively good selectivity with respect to alkaline, alkaline earth and some transition and heavy metal ions. They were employed for direct determination of lead in solder alloys and in galena rocks with a good agreement with the obtained results by atomic absorption spectroscopy.

Arachidonate metabolism increases as rat alveolar type II cells differentiate in vitro

International Nuclear Information System (INIS)

Lipchik, R.J.; Chauncey, J.B.; Paine, R.; Simon, R.H.; Peters-Golden, M.

1990-01-01

Rat type II alveolar epithelial cells are known to undergo morphological and functional changes when maintained in culture for several days. Having previously demonstrated that these cells can deacylate free arachidonic acid (AA) and metabolize it to products of the cyclooxygenase pathway, the present study was undertaken to determine whether in vitro differentiation was accompanied by alterations in the availability and metabolism of AA. We assessed the constitutive and ionophore A23187-induced deacylation and metabolism of endogenous AA, as well as the metabolism of exogenously supplied AA, in primary cultures of rat type II cells at days 2, 4, and 7 after isolation. Levels of free endogenous AA were increased at day 4, whereas eicosanoid synthesis, predominantly prostaglandin E2 and prostacyclin, increased markedly only at day 7. A similar time course of augmentation of prostanoid release was seen in response to exogenous AA. Type II cells cultured on fibronectin, intended to hasten cell flattening and spreading, demonstrated accelerated increases in available free AA in response to A23187; cells cultured on basement membrane derived from Engelbreth-Holm-Swarm mouse sarcoma, known to maintain the type II phenotype, exhibited diminished levels of available free AA. From these findings, we conclude that alterations in arachidonate metabolism are linked to alterations in cellular phenotype. The potentiation of eicosanoid synthesis accompanying in vitro differentiation suggests a possible role for the alveolar epithelium in the modulation of inflammation and fibrosis in the distal lung

The protective effect of cilostazol on isolated rabbit femoral arteries under conditions of ischemia and reperfusion: the role of the nitric oxide pathway

Directory of Open Access Journals (Sweden)

Mariana R.G.A. Santos

2012-01-01

Full Text Available OBJECTIVES: The clinical significance of ischemia/reperfusion of the lower extremities demands further investigation to enable the development of more effective therapeutic alternatives. This study investigated the changes in the vascular reactivity of the rabbit femoral artery and nitric oxide metabolites under partial ischemia/ reperfusion conditions following cilostazol administration. METHODS: Ischemia was induced using infrarenal aortic clamping. The animals were randomly divided into seven groups: Control 90 minutes, Ischemia/Reperfusion 90/60 minutes, Control 120 minutes, Ischemia/Reperfusion 120/90 minutes, Cilostazol, Cilostazol before Ischemia/Reperfusion 120/90 minutes, and Ischemia 120 minutes/Cilostazol/ Reperfusion 90 minutes. Dose-response curves for sodium nitroprusside, acetylcholine, and the calcium ionophore A23187 were obtained in isolated femoral arteries. The levels of nitrites and nitrates in the plasma and skeletal muscle were determined using chemiluminescence. RESULTS: Acetylcholine-and A23187-induced relaxation was reduced in the Ischemia/Reperfusion 120/90 group, and treatment with cilostazol partially prevented this ischemia/reperfusion-induced endothelium impairment. Only cilostazol treatment increased plasma levels of nitrites and nitrates. An elevation in the levels of nitrites and nitrates was observed in muscle tissues in the Ischemia/Reperfusion 120/90, Cilostazol/Ischemia/Reperfusion, and Ischemia/ Cilostazol/Reperfusion groups. CONCLUSION: Hind limb ischemia/reperfusion yielded an impaired endothelium-dependent relaxation of the femoral artery. Furthermore, cilostazol administration prior to ischemia exerted a protective effect on endotheliumdependent vascular reactivity under ischemia/reperfusion conditions.

Calcineurin regulates slow myosin, but not fast myosin or metabolic enzymes, during fast-to-slow transformation in rabbit skeletal muscle cell culture

Science.gov (United States)

Meißner, Joachim D; Gros, Gerolf; Scheibe, Renate J; Scholz, Michael; Kubis, Hans-Peter

2001-01-01

The addition of cyclosporin A (500 ng ml−1) - an inhibitor of the Ca2+-calmodulin-regulated serine/threonine phosphatase calcineurin - to primary cultures of rabbit skeletal muscle cells had no influence on the expression of fast myosin heavy chain (MHC) isoforms MHCIIa and MHCIId at the level of protein and mRNA, but reduced the expression of slow MHCI mRNA. In addition, no influence of cyclosporin A on the expression of citrate synthase (CS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA was found. The level of enzyme activity of CS was also not affected. When the Ca2+ ionophore A23187 (4 × 10−7m) was added to the medium, a partial fast-to-slow transformation occurred. The level of MHCI mRNA increased, and the level of MHCIId mRNA decreased. Cotreatment with cyclosporin A was able to prevent the upregulation of MHCI at the level of mRNA as well as protein, but did not reverse the decrease in MHCIId expression. The expression of MHCIIa was also not influenced by cyclosporin A. Cyclosporin A was not able to prevent the upregulation of CS mRNA under Ca2+ ionophore treatment and failed to reduce the increased enzyme activity of CS. The expression of GAPDH mRNA was reduced under Ca2+ ionophore treatment and was not altered under cotreatment with cyclosporin A. When the myotubes in the primary muscle culture were electrostimulated at 1 Hz for 15 min periods followed by pauses of 30 min, a partial fast-to-slow transformation was induced. Again, cotreatment with cyclosporin A prevented the upregulation of MHCI at the level of mRNA and protein without affecting MHCIId expression. The nuclear translocation of the calcineurin-regulated transcription factor nuclear factor of activated thymocytes (NFATc1) during treatment with Ca2+ ionophore, and the prevention of the translocation in the presence of cyclosporin A, were demonstrated immunocytochemically in the myotubes of the primary culture. The effects of cyclosporin A demonstrate the involvement of

Chelation of intracellular calcium blocks insulin action in the adipocyte

International Nuclear Information System (INIS)

Pershadsingh, H.A.; Shade, D.L.; Delfert, D.M.; McDonald, J.M.

1987-01-01

The hypothesis that intracellular Ca 2+ is an essential component of the intracellular mechanism of insulin action in the adipocyte was evaluated. Cells were loaded with the Ca 2+ chelator quin-2, by preincubating them with quin-2 AM, the tetrakis(acetoxymethyl) ester of quin-2. Quin-2 loading inhibited insulin-stimulated glucose transport without affecting basal activity. The ability of insulin to stimulate glucose uptake in quin-2-loaded cells could be partially restored by preincubating cells with buffer supplemented with 1.2 mM CaCl 2 and the Ca 2+ ionophore A23187. These conditions had no effect on basal activity and omission of CaCl 2 from the buffer prevented the restoration of insulin-stimulated glucose uptake by A23187. Quin-2 loading also inhibited insulin-stimulated glucose oxidation and the ability of insulin to inhibit cAMP-stimulated lipolysis without affecting their basal activities. Incubation of cells with 100 μM quin-2 or quin-2 AM had no effect on intracellular ATP concentration or the specific binding of 125 I=labeled insulin to adipocytes. These findings suggest that intracellular Ca 2+ is an essential component in the coupling of the insulin-activated receptor complex to cellular physiological/metabolic machinery. Furthermore, differing quin-2 AM dose-response profiles suggest the presence of dual Ca 2+ -dependent pathways in the adipocyte. One involves insulin stimulation of glucose transport and oxidation, whereas the other involves the antilipolytic action of insulin

Application of the Zona-Free Manipulation Technique to Porcine Somatic Nuclear Transfer

DEFF Research Database (Denmark)

Booth, Paul J; Tan, Shijian J; Holm, Peter

2001-01-01

cytoplast was agglutinated to a single granulosa cell (primary cultures grown in 0.5% serum for 2-5 days prior to use) in phytohaemagglutinin-P. Subsequently, each half cytoplast-granulosa cell couplet was simultaneously electrofused together and to another half cytoplast. Reconstructed embryos were...... activated in calcium ionophore A23187 followed by DMAP and were then individually cultured in microwells in NCSU-23 medium. On day 7 after activation, blastocyst yield and total cell numbers were counted. Of 279 attempted reconstructed NT embryos, 85.0 +/- 2.8% (mean +/- SEM; n = 5 replicates) successfully...... fused and survived activation. The blastocyst rate (per successfully fused and surviving embryo) was 4.8 +/- 2.3% (11/236; range, 0-12.8. Total blastocyst cell count was 36.0 +/- 4.5 (range, 18-58 cells). The blastocyst rate and total cell numbers of parthenogenetically activated and zona-free control...

Cell swelling activates K⁺ and Cl^- channels as well as nonselective, stretch-activated cation channels in ehrlich ascites tumor cells

DEFF Research Database (Denmark)

Christensen, Ove; Hoffmann, Else Kay

1992-01-01

Cell-attached patch-clamp recordings from Ehrlich ascites tumor cells reveal nonselective cation channels which are activated by mechanical deformation of the membrane. These channels are seen when suction is applied to the patch pipette or after osmotic cell swelling. The channel activation does...... system. In isolated insideout patches a Ca2+-dependent, inwardly rectifying K+ channel is demonstrated. The single-channel conductance recorded with symmetrical 150 mm K+ solutions is for inward current estimated at 40 pS and for outward current at 15 pS. Activation of the K+ channel takes place after...... by membrane stretch (suction). The time-averaged number of open K+ channels during regulatory volume decrease (RVD) can be estimated at 40 per cell. The number of open K+ channels following addition of Ca2+ plus ionophore A23187 was estimated at 250 per cell. Concurrent activation in cell-attached patches...

Human keratinocyte sensitivity towards inflammatory cytokines varies with culture time

Directory of Open Access Journals (Sweden)

G. Elliott

1992-01-01

Full Text Available Proliferating keratinocyte cultures have been reported to synthesize higher concentrations of prostaglandin (PG E than confluent ones. As interleukin-1 (IL-1 stimulates keratinocyte PGE synthesis we investigated whether the degree of confluency of the keratinocyte culture modified the response of the cells to IL-1. It was found that IL-1α (100 U/ml stimulated PGE2 synthesis by proliferating (7 days in culture but not differentiating (14 days in culture keratinocytes. Similar effects were observed using tumour necrosis factor-α. Both arachidonic acid (AA and the calcium ionophore A23187 stimulated PGE2 synthesis by 7 and 14 day cultures although the increase was greatest when 7 day cultures were used. Our data indicate that there is a specific down-regulation of the mechanism(s by which some inflammatory cytokines stimulate keratinocyte eicosanoid synthesis as cultured keratinocytes begin to differentiate.

Voltammetric Thin-Layer Ionophore-Based Films: Part 2. Semi-Empirical Treatment.

Science.gov (United States)

Yuan, Dajing; Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

2017-01-03

This work reports on a semiempirical treatment that allows one to rationalize and predict experimental conditions for thin-layer ionophore-based films with cation-exchange capacity read out with cyclic voltammetry. The transition between diffusional mass transport and thin-layer regime is described with a parameter (α), which depends on membrane composition, diffusion coefficient, scan rate, and electrode rotating speed. Once the thin-layer regime is fulfilled (α = 1), the membrane behaves in some analogy to a potentiometric sensor with a second discrimination variable (the applied potential) that allows one to operate such electrodes in a multianalyte detection mode owing to the variable applied ion-transfer potentials. The limit of detection of this regime is defined with a second parameter (β = 2) and is chosen in analogy to the definition of the detection limit for potentiometric sensors provided by the IUPAC. The analytical equations were validated through the simulation of the respective cyclic voltammograms under the same experimental conditions. While simulations of high complexity and better accuracy satisfactorily reproduced the experimental voltammograms during the forward and backward potential sweeps (companion paper 1), the semiempirical treatment here, while less accurate, is of low complexity and allows one to quite easily predict relevant experimental conditions for this emergent methodology.

Ionophorèse et électroporation : administration cutanée de médicaments et d'ADN

OpenAIRE

Préat, Véronique; Vandermeulen, Gaëlle; Daugimont, Liévin; Wascotte, Valentine

2009-01-01

La peau est une cible intéressante pour l'administration de médicaments et d'ADN qui cependant reste limitée par la faible perméabilité du stratum corneum. L'ionophorèse et l'électroporation ont été largement étudiées afin d'obtenir une administration transdermique. Dans les deux cas, le passage de courant perturbe la perméabilité de la peau et même la perméabilité cellulaire dans le cas précis de l'électroporation. Ces deux techniques permettent d'élargir le spectre des substances administra...

Divergent calcium signaling in RBCs from Tropidurus torquatus (Squamata – Tropiduridae strengthen classification in lizard evolution

Directory of Open Access Journals (Sweden)

Garcia Célia RS

2007-08-01

Full Text Available Abstract Background We have previously reported that a Teiid lizard red blood cells (RBCs such as Ameiva ameiva and Tupinambis merianae controls intracellular calcium levels by displaying multiple mechanisms. In these cells, calcium stores could be discharged not only by: thapsigargin, but also by the Na+/H+ ionophore monensin, K+/H+ ionophore nigericin and the H+ pump inhibitor bafilomycin as well as ionomycin. Moreover, these lizards possess a P2Y-type purinoceptors that mobilize Ca2+ from intracellular stores upon ATP addition. Results Here we report, that RBCs from the tropidurid lizard Tropidurus torquatus store Ca2+ in endoplasmic reticulum (ER pool but unlike in the referred Teiidae, these cells do not store calcium in monensin-nigericin sensitive pools. Moreover, mitochondria from T. torquatus RBCs accumulate Ca2+. Addition of ATP to a calcium-free medium does not increase the [Ca2+]c levels, however in a calcium medium we observe an increase in cytosolic calcium. This is an indication that purinergic receptors in these cells are P2X-like. Conclusion T. torquatus RBCs present different mechanisms from Teiid lizard red blood cells (RBCs, for controlling its intracellular calcium levels. At T. torquatus the ion is only stored at endoplasmic reticulum and mitochondria. Moreover activation of purinergic receptor, P2X type, was able to induce an influx of calcium from extracelullar medium. These studies contribute to the understanding of the evolution of calcium homeostasis and signaling in nucleated RBCs.

Immunodeficiency after allogeneic bone marrow transplantation in man. Effect of phorbol ester (phorbol myristate acetate) and calcium ionophore (A23187) in vitro

DEFF Research Database (Denmark)

Møller, J; Hofmann, B; Langhoff, E

1989-01-01

This study was undertaken to clarify the mechanism behind the severely decreased lymphocyte proliferative response upon stimulation with mitogens and antigens seen after allogeneic bone marrow transplantation (BMT) in man. We investigated eight BMT patients and eight controls and found...

Echinochrome A Release by Red Spherule Cells Is an Iron-Withholding Strategy of Sea Urchin Innate Immunity.

Science.gov (United States)

Coates, Christopher J; McCulloch, Claire; Betts, Joshua; Whalley, Tim

2018-01-01

Cellular immune defences in sea urchins are shared amongst the coelomocytes - a heterogeneous population of cells residing in the coelomic fluid (blood equivalent) and tissues. The most iconic coelomocyte morphotype is the red spherule cell (or amebocyte), so named due to the abundance of cytoplasmic vesicles containing the naphthoquinone pigment echinochrome A. Despite their identification over a century ago, and evidence of antiseptic properties, little progress has been made in characterising the immunocompetence of these cells. Upon exposure of red spherule cells from sea urchins, i.e., Paracentrotus lividus and Psammechinus miliaris, to microbial ligands, intact microbes, and damage signals, we observed cellular degranulation and increased detection of cell-free echinochrome in the coelomic fluid ex vivo. Treatment of the cells with ionomycin, a calcium-specific ionophore, confirmed that an increase in intracellular levels of Ca2+ is a trigger of echinochrome release. Incubating Gram-positive/negative bacteria as well as yeast with lysates of red spherule cells led to significant reductions in colony-forming units. Such antimicrobial properties were counteracted by the addition of ferric iron (Fe3+), suggesting that echinochrome acts as a primitive iron chelator in echinoid biological defences. © 2017 S. Karger AG, Basel.

Cytoplasmic free Ca2+ is essential for multiple steps in malaria parasite egress from infected erythrocytes

Directory of Open Access Journals (Sweden)

Glushakova Svetlana

2013-01-01

Full Text Available Abstract Background Egress of Plasmodium falciparum, from erythrocytes at the end of its asexual cycle and subsequent parasite invasion into new host cells, is responsible for parasite dissemination in the human body. The egress pathway is emerging as a coordinated multistep programme that extends in time for tens of minutes, ending with rapid parasite extrusion from erythrocytes. While the Ca2+ regulation of the invasion of P. falciparum in erythrocytes is well established, the role of Ca2+ in parasite egress is poorly understood. This study analysed the involvement of cytoplasmic free Ca2+ in infected erythrocytes during the multistep egress programme of malaria parasites. Methods Live-cell fluorescence microscopy was used to image parasite egress from infected erythrocytes, assessing the effect of drugs modulating Ca2+ homeostasis on the egress programme. Results A steady increase in cytoplasmic free Ca2+ is found to precede parasite egress. This increase is independent of extracellular Ca2+ for at least the last two hours of the cycle, but is dependent upon Ca2+ release from internal stores. Intracellular BAPTA chelation of Ca2+ within the last 45 minutes of the cycle inhibits egress prior to parasitophorous vacuole swelling and erythrocyte membrane poration, two characteristic morphological transformations preceding parasite egress. Inhibitors of the parasite endoplasmic reticulum (ER Ca2+-ATPase accelerate parasite egress, indicating that Ca2+ stores within the ER are sufficient in supporting egress. Markedly accelerated egress of apparently viable parasites was achieved in mature schizonts using Ca2+ ionophore A23187. Ionophore treatment overcomes the BAPTA-induced block of parasite egress, confirming that free Ca2+ is essential in egress initiation. Ionophore treatment of immature schizonts had an adverse effect inducing parasitophorous vacuole swelling and killing the parasites within the host cell. Conclusions The parasite egress

Cobalt uptake and binding in human red blood cells

DEFF Research Database (Denmark)

Simonsen, Lars Ole; Brown, Anthony M; Harbak, Henrik

2011-01-01

of cobalt, and also from the initial slope of the cobalt buffering curve. The cobalt accumulation is similar in fed and ATP-depleted cells. The buffering curve for [Co(T)](c) can be fitted by a Michaelis type function with B(max)=24 mmol (l cells)(-1) and half-saturation at 240 µM [Co(2+)](c). The tracer...... reversibly bound, being releasable by excess extracellular EGTA in the presence of A23187, and partly tightly bound, remaining in the cells even at high ionophore concentrations. The tightly bound fraction builds up over time, and is larger and develops earlier in fed cells compared to ATP-depleted cells......-migrate with hemoglobin in Sephadex column chromatography of a lysate of (57)Co-loaded cells. (57)Co also co-migrates with hemoglobin when added to a lysate of unlabeled cells or to a solution of purified hemoglobin, in both cases with a time-dependent development of tight binding. Cobalt is known to bind to the globin...

Influence of recipient cytoplasm cell stage on transcription in bovine nucleus transfer embryos

DEFF Research Database (Denmark)

Smith, Steven D.; Soloy, Eva; Kanka, Jiri

1996-01-01

Nucleus transfer for the production of multiple embryos derived from a donor embryo relies upon the reprogramming of the donor nucleus so that it behaves similar to a zygotic nucleus. One indication of nucleus reprogramming is the RNA synthetic activity. In normal bovine embryogenesis, the embryo....... NTE were produced using either a MII phase (nonactivated) cytoplasts at 32 hr of maturation or S-phase (activated) cytoplasts activated with calcium ionophore A23187 and cycloheximide treatment approximately 8 hr prior to fusion with a blastomere from an in-vitro-produced morula stage embryo at 32 hr...... of maturation. Control in-vitro-produced embryos were 3H-uridine-labelled and fixed at the 2-, 4-, early 8-, and late 8-cell stages. NTE were similarly prepared at 1, 3, and 20 hr postfusion and at the 2-, 4-, and 8-cell stages. In the control embryos, RNA synthesis was absent in the 2-, 4-, and early 8-cell...

Fluoxetine-induced inhibition of synaptosomal [3H]5-HT release: Possible Ca2+-channel inhibition

International Nuclear Information System (INIS)

Stauderman, K.A.; Gandhi, V.C.; Jones, D.J.

1992-01-01

Fluoxetine, a selective 5-Ht uptake inhibitor, inhibited 15 mM K + -induced [ 3 H]5-HT release from rat spinal cord and cortical synaptosomes at concentrations > 0.5 uM. This effect reflected a property shared by another selective 5-HT uptake inhibitor paroxetine but not by less selective uptake inhibitors such as amitriptyline, desipramine, imipramine or nortriptyline. Inhibition of release by fluoxetine was inversely related to both the concentration of K + used to depolarize the synaptosomes and the concentration of external Ca 2+ . Experiments aimed at determining a mechanism of action revealed that fluoxetine did not inhibit voltage-independent release of [ 3 H]5-HT release induced by the Ca 2+ -ionophore A 23187 or Ca 2+ -independent release induced by fenfluramine. Moreover the 5-HT autoreceptor antagonist methiothepin did not reverse the inhibitory actions of fluoxetine on K + -induced release. Further studies examined the effects of fluoxetine on voltage-dependent Ca 2+ channels and Ca 2+ entry

Hydrocortisone selectively inhibits IgE-dependent arachidonic acid release from rat peritoneal mast cells

International Nuclear Information System (INIS)

Heiman, A.S.; Crews, F.T.

1984-01-01

Purified rat mst cells were used to study the effects of antiinflammatory steroids on the release of [1-14C]-arachidonic acid ([1-14C]AA) and metabolites. Mast cell were incubated overnight with glucocorticoids, [1-14C]AA incorporated into cellular phospholipids and the release of [1-14C]AA, and metabolites determined using a variety of secretagogues. Release of [1-14C]AA and metabolites by concanavalin A, the antigen ovalbumin and anti-immunoglobulin E antibody was markedly reduced by glucocorticoid treatment. Neither the total incorporation of [1-14C]AA nor the distribution into phospholipids was altered by hydrocortisone pretreatment. Glucocorticoid pretreatment did not alter [1-14C]AA release stimulated by somatostatin, compound 48/80, or the calcium ionophore, A23187. These data indicate that antiinflammatory steroids selectively inhibit immunoglobulin dependent release of arachidonic acid from rat mast cells. These findings question the role of lipomodulin and macrocortin as general phospholipase inhibitors and suggest that they may be restricted to immunoglobulin stimuli

Calcium-mediated signaling and calmodulin-dependent kinase regulate hepatocyte-inducible nitric oxide synthase expression.

Science.gov (United States)

Zhang, Baochun; Crankshaw, Will; Nesemeier, Ryan; Patel, Jay; Nweze, Ikenna; Lakshmanan, Jaganathan; Harbrecht, Brian G

2015-02-01

Induced nitric oxide synthase (iNOS) is induced in hepatocytes by shock and inflammatory stimuli. Excessive NO from iNOS mediates shock-induced hepatic injury and death, so understanding the regulation of iNOS will help elucidate the pathophysiology of septic shock. In vitro, cytokines induce iNOS expression through activation of signaling pathways including mitogen-activated protein kinases and nuclear factor κB. Cytokines also induce calcium (Ca(2+)) mobilization and activate calcium-mediated intracellular signaling pathways, typically through activation of calmodulin-dependent kinases (CaMK). Calcium regulates NO production in macrophages but the role of calcium and calcium-mediated signaling in hepatocyte iNOS expression has not been defined. Primary rat hepatocytes were isolated, cultured, and induced to produce NO with proinflammatory cytokines. Calcium mobilization and Ca(2+)-mediated signaling were altered with ionophore, Ca(2+) channel blockers, and inhibitors of CaMK. The Ca(2+) ionophore A23187 suppressed cytokine-stimulated NO production, whereas Ethylene glycol tetraacetic acid and nifedipine increased NO production, iNOS messenger RNA, and iNOS protein expression. Inhibition of CaMK with KN93 and CBD increased NO production but the calcineurin inhibitor FK 506 decreased iNOS expression. These data demonstrate that calcium-mediated signaling regulates hepatocyte iNOS expression and does so through a mechanism independent of calcineurin. Changes in intracellular calcium levels may regulate iNOS expression during hepatic inflammation induced by proinflammatory cytokines. Copyright © 2015 Elsevier Inc. All rights reserved.

Fast Potentiometric Analysis of Lead in Aqueous Medium under Competitive Conditions Using an Acridono-Crown Ether Neutral Ionophore

Directory of Open Access Journals (Sweden)

Ádám Golcs

2018-05-01

Full Text Available Lead is a particularly toxic heavy metal that is present above acceptable levels in the water of many countries. This article describes a quick detection method of lead(II ions using a polyvinyl chloride (PVC-based ion-selective membrane electrode containing an acridono-crown ether ionophore by potentiometry. The electrochemical cell exhibits a Nernstian response for lead(II ions between the concentration range of 10−4 to 10−2 M, and can be used in the pH range of 4–7. The applicability of this sensor was verified by measuring a multicomponent aqueous sample. Under the given conditions, this electrode is suitable for the selective quantitative analysis of lead(II ions in the presence of many additional metal ions.

Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

International Nuclear Information System (INIS)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha

2007-01-01

The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S 1 ) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S 1 ) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10 -8 to 1.0 x 10 -1 M Cd 2+ with limit of detection 5.0 x 10 -8 M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

Energy Technology Data Exchange (ETDEWEB)

Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

2007-02-05

The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

Suppressed histamine release from rat peritoneal mast cells by ultraviolet B irradiation: decreased diacylglycerol formation as a possible mechanism

International Nuclear Information System (INIS)

Danno, K.; Fujii, K.; Tachibana, T.; Toda, K.; Horio, T.

1988-01-01

This study was designed to investigate the effect of ultraviolet B (UVB) irradiation on mast cell functions. Purified mast cells obtained from rat peritoneal cavity were irradiated with UVB and subsequently exposed to a degranulator, compound 48/80, or the calcium ionophore A-23187. The amount of histamine released from mast cells measured by the enzyme isotopic assay was significantly decreased by UVB irradiation (100-400 mJ/cm2). Within this dose range, UVB alone was not cytotoxic to the cells because it did not induce histamine release. The suppression was observed when mast cells were subjected to degranulation without intervals after UVB irradiation, and even after 5 h postirradiation. The wavelength of 300 nm from a monochromatic light source showed the maximum effect. When mast cells prelabeled with [ 3 H]arachidonate were irradiated and challenged by compound 48/80, label accumulation in diacylglycerol produced by the phosphatidylinositol cycle was considerably decreased by UVB irradiation. From these results, we hypothesize that, within an adequate irradiation dose, UVB irradiation suppresses histamine release from mast cells, probably by causing noncytotoxic damage to the membrane phospholipid metabolism, which is tied to the degranulation mechanisms

Selective permeation of plutonium(IV) through a supported liquid membrane containing tri-iso-amyl phosphate as an ionophore

International Nuclear Information System (INIS)

Shukla, J.P.; Kedari, C.S.; Dharmapurikar, G.R.

1998-01-01

Selective ionophoric mobility of plutonium with ease of concentration upgradation from aqueous nitrate solutions was investigated. A thin flat-sheet supported liquid membrane (SLM) impregnated with tri-iso-amyl phosphate (TAP) was used. Accurel polypropylene hydrophobic microporous membrane 'Enka' was tested as the solid polymeric support. The source phase generally contained extremely dilute (ca. 10 -6 mol/dm -3 ) to moderately concentrated plutonium(IV) nitrate solutions (ca. 10 -3 mol/dm -3 ) in about 4 mol/dm -3 HNO 3 . Membrane permeability and selectivity dependency on variables like nitric acid concentration in the source phase, carrier concentration, receiving phase composition, etc. were systematically evaluated. More than 90% pertraction of plutonium could be easily accomplished in single run employing a feed solution consisting of about 1 mg/dm -3 Pu and 4 mol/dm -3 HNO 3 , carrier concentration of 0.8 mol/dm -3 TAP/dodecane; the receiving phase was 0.5 mol/dm -3 sodium carbonate or 0.5 mol/dm -3 ascorbic acid. The selective diffusivity of plutonium(IV) was observed from various effluents originating from fuel reprocessing operations. Reusability of membrane supports was also found to be satisfactory. (author)

Protective effects of a standard extract of Mangifera indica L. (VIMANG) against mouse ear edemas and its inhibition of eicosanoid production in J774 murine macrophages.

Science.gov (United States)

Garrido, G; González, D; Lemus, Y; Delporte, C; Delgado, R

2006-06-01

A standard aqueous extract of Mangifera indica L., used in Cuba as antioxidant under the brand name VIMANG, was tested in vivo for its anti-inflammatory activity, using commonly accepted assays. The standard extract of M. indica, administered orally (50-200mg/kg body wt.), reduced ear edema induced by arachidonic acid (AA) and phorbol myristate acetate (PMA) in mice. In the PMA model, M. indica extract also reduced myeloperoxidase (MPO) activity. In vitro studies were performed using macrophage cell line J774 stimulated with pro-inflammatory stimuli lipopolysaccharide-interferon gamma (LPS-IFNgamma) or calcium ionophore A23187 to determine prostaglandin PGE(2) or leukotriene LTB(4) release, respectively. The extract inhibited the induction of PGE(2) and LTB(4) with IC(50) values of 21.7 and 26.0microg/ml, respectively. Mangiferin (a glucosylxanthone isolated from the extract) also inhibited these AA metabolites (PGE(2), IC(50) value=17.2microg/ml and LTB(4), IC(50) value=2.1microg/ml). These results represent an important contribution to the elucidation of the mechanism involved in the anti-inflammatory and anti-nociceptive effects reported for the standard extract of M. indica VIMANG.

Fabrication of a highly selective cadmium (II) sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane as a supramolecular ionophore

Energy Technology Data Exchange (ETDEWEB)

Ghaemi, Arezoo, E-mail: arezooghaemi@yahoo.com; Tavakkoli, Haman; Mombeni, Tayebeh

2014-05-01

A new cadmium (II) ion selective sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (kryptofix5) as a supramolecular carrier has been developed. The membrane solutions containing polyvinyl chloride (PVC), plasticizer, sodium tetraphenylborate (NaTPB) as a lipophilic ionic additive and kryptofix5 as an ionophore were directly coated on the surface of graphite rods. The best composition of the coated membrane (w/w%) was found to be: 30.0% PVC, 61.0% dioctyl sebacate (DOS), 6.0% NaTPB and 3.0% kryptofix5. The sensor indicates a good linear response for Cd{sup 2+} cation over a wide concentration range from 1.0 × 10{sup −5} to 1.0 × 10{sup −1} M with a Nernstian slope of 29.8 ± 0.1 mV/decade and the detection limit is 8.4 × 10{sup −6} M. The response time of the sensor is 15 s and it can be used for 7 weeks without significant drift in potential. The sensor operates in the wide pH range of 1.0–6.0. This sensor reveals a very good selectivity toward Cd{sup 2+} ion over a wide range of alkali, transition and heavy metal cations. The sensor was used as an indicator electrode for potentiometric titration of Cd{sup 2+} using sodium fluoride and ethylenediaminetetraacetic acid (EDTA) solutions with a sharp potential change that occurred at the end point. In addition, the proposed sensor was successfully used for determination of Cd{sup 2+} cation in real water samples. - Graphical abstract: Fabrication of a highly selective cadmium (II) sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane as a supramolecular ionophore. - Highlights: • Fabrication of a novel Cd{sup 2+} selective sensor with high sensitivity and selectivity • Using fabricated sensor in a wide pH range with fast response time • Replacing expensive techniques with this low cost sensor with low detection limit • Excellent capability of this sensor for measuring Cd{sup 2+} in real samples.

Phosphatidylserine-stimulated production of N-acyl-phosphatidylethanolamines by Ca2+-dependent N-acyltransferase.

Science.gov (United States)

Hussain, Zahir; Uyama, Toru; Kawai, Katsuhisa; Binte Mustafiz, Smriti Sultana; Tsuboi, Kazuhito; Araki, Nobukazu; Ueda, Natsuo

2018-05-01

N-acyl-phosphatidylethanolamine (NAPE) is known to be a precursor for various bioactive N-acylethanolamines including the endocannabinoid anandamide. NAPE is produced in mammals through the transfer of an acyl chain from certain glycerophospholipids to phosphatidylethanolamine (PE) by Ca 2+ -dependent or -independent N-acyltransferases. The ε isoform of mouse cytosolic phospholipase A 2 (cPLA 2 ε) was recently identified as a Ca 2+ -dependent N-acyltransferase (Ca-NAT). In the present study, we first showed that two isoforms of human cPLA 2 ε function as Ca-NAT. We next purified both mouse recombinant cPLA 2 ε and its two human orthologues to examine their catalytic properties. The enzyme absolutely required Ca 2+ for its activity and the activity was enhanced by phosphatidylserine (PS). PS enhanced the activity 25-fold in the presence of 1 mM CaCl 2 and lowered the EC 50 value of Ca 2+ >8-fold. Using a PS probe, we showed that cPLA 2 ε largely co-localizes with PS in plasma membrane and organelles involved in the endocytic pathway, further supporting the interaction of cPLA 2 ε with PS in living cells. Finally, we found that the Ca 2+ -ionophore ionomycin increased [ 14 C]NAPE levels >10-fold in [ 14 C]ethanolamine-labeled cPLA 2 ε-expressing cells while phospholipase A/acyltransferase-1, acting as a Ca 2+ -independent N-acyltransferase, was insensitive to ionomycin for full activity. In conclusion, PS potently stimulated the Ca 2+ -dependent activity and human cPLA 2 ε isoforms also functioned as Ca-NAT. Copyright © 2018 Elsevier B.V. All rights reserved.

Receptor-mediated inhibition of adenylate cyclase and stimulation of arachidonic acid release in 3T3 fibroblasts. Selective susceptibility to islet-activating protein, pertussis toxin

International Nuclear Information System (INIS)

Murayama, T.; Ui, M.

1985-01-01

Thrombin exhibited diverse effects on mouse 3T3 fibroblasts. It (a) decreased cAMP in the cell suspension, (b) inhibited adenylate cyclase in the Lubrol-permeabilized cell suspension in a GTP-dependent manner, increased releases of (c) arachidonic acid and (d) inositol from the cell monolayer prelabeled with these labeled compounds, (e) increased 45 Ca 2+ uptake into the cell monolayer, and (f) increased 86 Rb + uptake into the cell monolayer in a ouabain-sensitive manner. Most of the effects were reproduced by bradykinin, platelet-activating factor, and angiotensin II. The receptors for these agonists are thus likely to be linked to three separate effector systems: the adenylate cyclase inhibition, the phosphoinositide breakdown leading to Ca 2+ mobilization and phospholipase A2 activation, and the Na,K-ATPase activation. Among the effects of these agonists, (a), (b), (c), and (e) were abolished, but (d) and (f) were not, by prior treatment of the cells with islet-activating protein (IAP), pertussis toxin, which ADP-ribosylates the Mr = 41,000 protein, the alpha-subunit of the inhibitory guanine nucleotide regulatory protein (Ni), thereby abolishing receptor-mediated inhibition of adenylate cyclase. The effects (a), (c), (d), and (e) of thrombin, but not (b), were mimicked by A23187, a calcium ionophore. The effects of A23187, in contrast to those of receptor agonists, were not affected by the treatment of cells with IAP. Thus, the IAP substrate, the alpha-subunit of Ni, or the protein alike, may play an additional role in signal transduction arising from the Ca 2+ -mobilizing receptors, probably mediating process(es) distal to phosphoinositide breakdown and proximal to Ca 2+ gating

Equol is more active than soy isoflavone itself to compete for binding to thromboxane A(2) receptor in human platelets.

Science.gov (United States)

Muñoz, Yenny; Garrido, Argelia; Valladares, Luis

2009-03-01

Several dietary intervention studies examining the health effect of soy isoflavones allude to the importance of equol in establishing the cardiovascular response to soy protein. Although, the specific mechanism by which this action occurs has not been established. The aim of this study was to investigate the inhibitory effect of soy-isoflavones and the metabolite of daidzein, equol, on agonist-induced platelet responses dependent on thromboxane A(2) (TxA(2)) receptor. Competitive radioligand binding assay was used to screen for affinity of these compounds to the TxA(2) receptor. The effect of equol on platelet activation, evaluate through of release of the ATP, by analogs of TxA(2) was analyzed. The effect of equol on platelet aggregation was investigated with ADP, U46619 (a TxA(2) mimic) and the calcium ionophore A23187. The data showed that aglycone isoflavones and equol bind to TxA(2) receptor in the micromol/L range, whereas their glucoside derivates had very low binding activity for this receptor. Under equilibrium conditions, the following order of the relative affinity in inhibiting [(3)H]-SQ29585 binding was: equol>genistein>daidzein>glycitein>genistin, daidzin, glycitin. Equol interaction was reversible and competitive for labeled-SQ29548 with not apparent decrease in the number of TxA(2) binding sites. In addition, from platelet activation studies, equol effectively inhibited ATP secretion elicited by the TxA(2) analog U46619. On the other hand, equol inhibited the platelet aggregation induced by U46619 and A23187, while it failed to inhibit that induced by ADP. The aglycone isoflavones from soy, and particularly equol, have been found to have biological effects attributable to thromboxane A(2) receptor antagonism. These findings may help elucidate how dietary isoflavone modulate platelet function and explain why soy-rich foods are claimed to have beneficial effects in the prevention of thrombotic events.

A novel dioxygenation product of arachidonic acid possesses potent chemotactic activity for human polymorphonuclear leukocytes.

Science.gov (United States)

Shak, S; Perez, H D; Goldstein, I M

1983-12-25

We have found that a novel dioxygenation product of arachidonic acid, 8(S),15(S)-dihydroxy-5,11-cis-9,13-trans-eicosatetraenoic acid (8,15-diHETE), possesses chemotactic activity for human polymorphonuclear leukocytes comparable to that of leukotriene B4. Authentic 8,15-diHETE, identified by gas chromatography-mass spectrometry, was prepared by treating arachidonic acid with soybean lipoxygenase and was purified by reverse-phase high performance liquid chromatography. Using a "leading front" assay, 8,15-diHETE exhibited significant chemotactic activity at a concentration of 5.0 ng/ml. Maximum chemotactic activity was observed at a concentration of 30 ng/ml. The 8,15-diHETE generated by mixed human leukocytes after stimulation with arachidonic acid and the calcium ionophore, A23187, exhibited quantitatively similar chemotactic activity. Two synthetic all-trans conjugated isomers of 8,15-diHETE, however, were not chemotactic at concentrations up to 500 ng/ml. In contrast to its potent chemotactic activity, 8,15-diHETE (at concentrations up to 10 micrograms/ml) was relatively inactive with respect to its ability to provoke either degranulation or generation of superoxide anion radicals by cytochalasin B-treated leukocytes. Both leukotriene B4 and 8,15-diHETE may be important mediators of inflammation.

Bacterial metabolism of human polymorphonuclear leukocyte-derived arachidonic acid.

Science.gov (United States)

Sorrell, T C; Muller, M; Sztelma, K

1992-05-01

Evidence for transcellular bacterial metabolism of phagocyte-derived arachidonic acid was sought by exposing human blood polymorphonuclear leukocytes, prelabelled with [3H]arachidonic acid, to opsonized, stationary-phase Pseudomonas aeruginosa (bacteria-to-phagocyte ratio of 50:1) for 90 min at 37 degrees C. Control leukocytes were stimulated with the calcium ionophore A23187 (5 microM) for 5 min. Radiochromatograms of arachidonic acid metabolites, extracted from A23187-stimulated cultures and then separated by reverse-phase high-performance liquid chromatography, revealed leukotriene B4, its omega-oxidation products, and 5-hydroxy-eicosatetraenoic acid. In contrast, two major metabolite peaks, distinct from known polymorphonuclear leukocyte arachidonic acid products by high-performance liquid chromatography or by thin-layer chromatography, were identified in cultures of P. aeruginosa with [3H]arachidonic acid-labelled polymorphonuclear leukocytes. Respective chromatographic characteristics of these novel products were identical to those of two major metabolite peaks produced by incubation of stationary-phase P. aeruginosa with [3H]arachidonic acid. Production of the metabolites was dependent upon pseudomonal viability. UV spectral data were consistent with a conjugated diene structure. Metabolism of arachidonic acid by P. aeruginosa was not influenced by the presence of catalase, superoxide dismutase, nordihydroguaiaretic acid, ethanol, dimethyl sulfoxide, or ferrous ions but was inhibited by carbon monoxide, ketoconazole, and 1,2-epoxy-3,3,3-trichloropropane. Our data suggest that pseudomonal metabolism of polymorphonuclear leukocyte-derived arachidonic acid occurs during phagocytosis, probably by enzymatic epoxidation and hydroxylation via an oxygenase. By this means, potential proinflammatory effects of arachidonic acid or its metabolites may be modulated by P. aeruginosa at sites of infection in vivo.

I. Lipid metabolism stimulated by altered intracellular calcium in cultured fibroblasts. II. Regulation of the activity of rat adipose tissue lipoprotein lipase

International Nuclear Information System (INIS)

Chang Wang, Huei-Hsiang Lisa.

1988-01-01

The cell killing process of 3T3 Swiss mouse fibroblasts stimulated by Ca 2+ plus A23187, a Ca 2+ ionophore has been studied. The aim of this research is to understand the biochemical mechanism of this process, i.e, to elucidate the step involved and to characterize the enzymes involved with each steps in the lipid metabolism stimulated in cultured fibroblasts undergoing a toxic death response. Parallel 3T3 cultures biosynthetically labeled with lipid precursors were examined under Ca 2+ -mediated killing conditions. Labeled lipids were extracted and analyzed by thin-layer chromatography and autoradiography. Evidence for activation of a phosphatidylinositol-specific phospholipase C has been obtained in injured 3T3 cells labeled with [ 3 H]glycerol and [ 3 H]inositol. To simplify the system for studying the lipoprotein lipase reaction, our laboratory prepared the chromophore containing a substrate: 1,2-dipalmitoyl-3-β-2-furylacryloyltriacylglycerol (DPFATG). By using this artificial lipid we could readily investigate the lipoprotein lipase reactions, since the absorbance change directly represents the hydrolysis of the chromophoric side chain of the substrate

Cortisol rapidly reduces prolactin release and cAMP and 45Ca2+ accumulation in the cichlid fish pituitary in vitro

International Nuclear Information System (INIS)

Borski, R.J.; Helms, L.M.H.; Richman, N.H. III; Grau, E.G.

1991-01-01

During in vitro incubation, prolactin release is inhibited in a dose-related manner by cortisol. This action is mimicked by the synthetic glucocorticoid agonist dexamethasone but not by other steroids tested. Perifusion studies indicate that the inhibition of [ 3 H]prolactin release by cortisol occurs within 20 min. Cortisol (50 nM) also inhibits cAMP accumulation and reduces 45 Ca 2+ accumulation in the tilapia rostral pars distalis within 15 min. Cortisol's action on prolactin release is blocked in the presence of either the Ca 2+ ionophore A23187 or a combination of dibutyryl cAMP and 3-isobutyl-1-methylxanthine, which increase intracellular Ca 2+ and cAMP, respectively. Taken together, these findings suggest that cortisol may play a physiologically relevant role in the rapid modulation of prolactin secretion in vivo. These studies also suggest that the inhibition of prolactin release by cortisol is a specific glucocorticoid action that may be mediated, in part, through cortisol's ability to inhibit intracellular cAMP and Ca 2+ metabolism

Anti-Inflammatory and Antipruritic Effects of Luteolin from Perilla (P. frutescens L. Leaves

Directory of Open Access Journals (Sweden)

In Hwa Jeon

2014-05-01

Full Text Available Perilla (Perilla frutescens L. leaves have shown therapeutic efficacy in the treatment of inflammatory disorders, allergies, bronchial asthma, and systemic damage due to free radicals. In the present study we analyzed the active constituents in perilla leaves using high-performance liquid chromatography (HPLC and isolated luteolin, a polyphenolic flavonoid. We investigated the anti-inflammatory and antipruritic properties of luteolin. Luteolin inhibited the secretion of inflammatory cytokines such as interleukin-1β (IL-1 β and tumor necrosis factor-α (TNF-α from human mast cells (HMC-1 stimulated with phorbol myristate acetate plus calcium ionophore A23187 in a dose-dependent manner. Luteolin also significantly reduced the histamine release from rat peritoneal mast cells stimulated by compound 48/80, a potent histamine liberator. Furthermore, the administration of luteolin markedly inhibited the scratching behavior and vascular permeability induced by pruritogens, such as compound 48/80 or serotonin, in ICR mice. These results suggested that luteolin has potential as a therapeutic agent against inflammation and itch-related skin diseases.

Null-point titration measurements of free magnesium in stored erythrocytes

International Nuclear Information System (INIS)

Bock, J.L.; Yusuf, Y.; Puntillo, E.

1987-01-01

Free intracellular magnesium concentration (Mg/sub i/) was measured in stored human erythrocytes, using null-point titration with ionophore A23187. For cells stored 31 P NMR spectroscopy, which showed a decrease in Mg/sub i/ with storage. However, the NMR measurements are performed with no pretreatment of the cells, while the null-point method requires an initial washing step, which alters pH/sub i/ and may also alter Mg/sub i/. The titration-measured Mg/sub i/ values are still surprisingly low for long-stored cells, considering that depletion of ATP and 2,3-DPG should release bound Mg. Using the titration-measured Mg/sub i/ values along with measurements of total Mg, ATP, and 2,3-DPG, they estimate that an additional buffer contains about 47% of total Mg in cells stored 21 days. Mg/sub i/ determinations by both 31 P NMR and null-point titration thus indicate that erythrocyte Mg is largely bound to a high-capacity, low-affinity buffer whose relative importance increases during cell storage. Discrepancies between the methods require further investigation

Carrier-facilitated transport of Cd(II) through a supported liquid membrane containing thiacalix[4]arene derivatives as ionophore

International Nuclear Information System (INIS)

Zaghbani, Asma; Tayeb, Rafik; Dhahbi, Mahmoud

2009-01-01

The feasibility of a facilitated transport process of cadmium ions through a SLM system incorporating new extractant agents, thiacalix[4]arenes, was studied. These molecules have sulfur atoms instead of usual methylene bridges. The chemical modification of the upper or the lower rim provides a great variety of supra molecules having different complexation ability and different conformational behaviour. The efficiency of the transport across the inner membrane organic liquid phase is shown to depend on the chemical (affinity) and structural (conformational states possible) parameters of these complexing molecules. In this work, two different thiacalix[4]arenes were selected as effective ionophore for the treatment of liquid media loaded in Cd(II). The results show that these thiacalix[4]arenes derivative ensure facilitated transport of cadmium cations through supported liquid membranes. Especially, the non-substituted thiacalix[4]arene can be considered as an effective extractant agent. The incidence of several parameters on transport efficiency such as pH of both aqueous solutions and carrier concentration was studied. The permeation of the species is due to a proton potential gradient (the driving force of the process) existing between the two opposite sides of the SLM. The initial flux, J, is found to be equal to 6.7.10 -7 mol.m -2 .s -1 , under optimal experimental conditions.

Inhibition of Suicidal Erythrocyte Death by Indirubin-3’-Monoxime

Directory of Open Access Journals (Sweden)

Chunqiu Liu

2018-02-01

Full Text Available Background/Aims: Qing Dai is a prized traditional Chinese medicine whose major component, indirubin, and its derivative, indirubin-3’-monoxime (IDM, have inhibitory effects on the growth of many human tumor cells and pronounced anti-leukemic activities. However, the effects of IDM on mature human erythrocytes are unclear. This study aimed to evaluate the potential impact of IDM on erythrocytes and the mechanisms underlying that impact. Methods: Utilizing flow cytometry and confocal laser scanning microscopy, phosphatidylserine exposure at the cell surface was estimated by annexin V-fluorescein isothiocyanate (FITC. The relative cell size, expressed in arbitrary units, was evaluated by forward scatter in a flow cytometer. Fluo-3 fluorescence was used to bewrite changes in cytosolic Ca2+ activity, reactive oxygen species (ROS formation was assessed by 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA fluorescence, and ceramide abundance was evaluated by FITC-conjugated specific antibodies. Results: The 24-h exposure of human erythrocytes to IDM (12 µM significantly decreased the percentage of annexin V-binding erythrocytes and the intracellular calcium concentration ([Ca2+]i. IDM (3-12 µM did not significantly modify the ceramide level or DCFH-DA fluorescence. Energy depletion (removal of glucose for 24 hours significantly increased annexin V binding and Fluo-3 fluorescence and diminished forward scatter, and these effects were significantly mitigated by IDM (12 µM. Moreover, the Ca2+ ionophore ionomycin (1 µM, 60 min and oxidative stress (30 min exposure to 0.05 mM tert-butyl hydroperoxide, t-BHP similarly triggered eryptosis, which was also significantly suppressed by IDM. Conclusions: IDM is a novel inhibitor of suicidal erythrocyte death following ionomycin treatment, t-BHP treatment and energy depletion. Thus, IDM may counteract anemia and impairment of microcirculation, at least in part, by inhibition of Ca2+ entry into erythrocytes.

Hamster thecal cells express muscle characteristics

International Nuclear Information System (INIS)

Self, D.A.; Schroeder, P.C.; Gown, A.M.

1988-01-01

Contraction of the follicular wall about the time of ovulation appears to be a coordinated event; however, the cells that mediate it remain poorly studied. We examined the theca externa cells in the wall of hamster follicles for the presence of a functional actomyosin system, both in developing follicles and in culture. We used a monoclonal antibody (HHF35) that recognizes the alpha and gamma isoelectric variants of actin normally found in muscle, but not the beta variant associated with non-muscle sources, to evaluate large preovulatory follicles for actin content and composition. Antibody staining of sectioned ovaries showed intense circumferential reactivity in the outermost wall of developing follicles. Immunoblots from two-dimensional gels of theca externa lysates demonstrated the presence of the two muscle-specific isozymes of actin. Immunofluorescence of cultured follicular cells pulse-labeled with [3H] thymidine (for autoradiographic detection of DNA replication) revealed the presence, in many dividing cells, of actin filaments aligned primarily along the longitudinal axis of the cells. In cultures exposed to the calcium ionophore A23187 (10(-4) M) for varying periods (5 min to 1 h), contraction of many individual muscle-actin-positive cells was observed. Immunofluorescence of these cells, fixed immediately after ionophore-induced contraction, revealed compaction of the actin filaments. Our findings demonstrate that the cells of the theca externa contain muscle actins from an early stage and that these cells are capable of contraction even while proliferating in subconfluent cultures. They suggest that follicular growth may include a naturally occurring developmental sequence in which a contractile cell type proliferates in the differentiated state

Detection and quantification of ionophore antibiotics in runoff, soil and poultry litter.

Science.gov (United States)

Sun, Peizhe; Barmaz, Delphine; Cabrera, Miguel L; Pavlostathis, Spyros G; Huang, Ching-Hua

2013-10-18

Ionophore antibiotics (IPAs) are widely used as coccidiostats in poultry and other livestock industries to promote growth and prevent infections. Because most of the ingested IPAs are excreted in poultry litter, which is primarily applied as grassland fertilizer, a significant amount of IPAs can be released into the litter-soil-water environment. A robust analytical method has been developed to quantify IPAs (monensin (MON), salinomycin (SAL) and narasin (NAR)) in complex environmental compartments including surface runoff, soil and poultry litter, with success to minimize matrix interference. The method for water samples involves solid-phase extraction (SPE) followed by liquid-liquid extraction (LLE) post-clean up steps. The method for solid samples involves bi-solvent LLE. IPAs were detected by HPLC-MS, with optimized parameters to achieve the highest sensitivity. Nigericin (NIG), an IPA not used in livestock industry, is successfully applied and validated as a surrogate standard. The method recoveries were at 92-95% and 81-85% in runoff samples from unfertilized and litter-fertilized fields, respectively. For solids, the method recoveries were at 93-99% in soils, and 79-83% in poultry litter samples. SAL was detected at up to 22mg/kg and MON and NAR at up to 4mg/kg in broiler litter from different farms. Up to 183μg/kg of MON was detected in litter-fertilized soils. All three IPAs were detected in the rainfall runoff from litter-fertilized lands at concentrations up to 9μg/L. Copyright © 2013 Elsevier B.V. All rights reserved.

Anti-allergic effects of a nonameric peptide isolated from the intestine gastrointestinal digests of abalone (Haliotis discus hannai) in activated HMC-1 human mast cells.

Science.gov (United States)

Ko, Seok-Chun; Lee, Dae-Sung; Park, Won Sun; Yoo, Jong Su; Yim, Mi-Jin; Qian, Zhong-Ji; Lee, Chang-Min; Oh, Junghwan; Jung, Won-Kyo; Choi, Il-Whan

2016-01-01

The aim of the present study was to examine whether the intestine gastrointestinal (GI) digests of abalone [Haliotis discus hannai (H. discus hannai)] modulate inflammatory responses and to elucidate the mechanisms involved. The GI digests of the abalone intestines were fractionated into fractions I (>10 kDa), II (5-10 kDa) and Ⅲ (abalone intestine GI digests (AIGIDs), fraction Ⅲ inhibited the passive cutaneous anaphylaxis (PCA) reaction in mice. Subsequently, a bioactive peptide [abalone intestine GI digest peptide (AIGIDP)] isolated from fraction Ⅲ was determined to be 1175.2 Da, and the amino acid sequence was found to be PFNQGTFAS. We noted that the purified nonameric peptide (AIGIDP) attenuated the phorbol‑12‑myristate 13-acetate plus calcium ionophore A23187 (PMACI)-induced histamine release and the production of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in human mast cells (HMC-1 cells). In addition, we also noted that AIGIDP inhibited the PMACI‑induced activation of nuclear factor‑κB (NF-κB) by suppressing IκBα phosphorylation and that it suppressed the production of cytokines by decreasing the phosphorylation of JNK. The findings of our study indicate that AIGIDP exerts a modulatory, anti-allergic effect on mast cell-mediated inflammatory diseases.

Rapid Upregulation of Orai1 Abundance in the Plasma Membrane of Platelets Following Activation with Thrombin and Collagen Related Peptide

Directory of Open Access Journals (Sweden)

Guilai Liu

2015-11-01

Full Text Available Background: Blood platelets accomplish primary hemostasis following vascular injury and contribute to the orchestration of occlusive vascular disease. Platelets are activated by an increase of cytosolic Ca2+-activity ([Ca2+]i, which is accomplished by Ca2+-release from intracellular stores and subsequent store operated Ca2+ entry (SOCE through Ca2+ release activated Ca2+ channel moiety Orai1. Powerful activators of platelets include thrombin and collagen related peptide (CRP, which are in part effective by activation of small G- protein Rac1. The present study explored the influence of thrombin and CRP on Orai1 protein abundance and cytosolic Ca2+-activity ([Ca2+]i in platelets drawn from wild type mice. Methods: Orai1 protein surface abundance was quantified utilizing CF™488A conjugated antibodies, and [Ca2+]i was determined with Fluo3-fluorescence. Results: In resting platelets, Orai1 protein abundance and [Ca2+]i were low. Thrombin (0.02 U/ml and CRP (5ug/ml within 2 min increased [Ca2+]i and Orai1 protein abundance at the platelet surface. [Ca2+]i was further increased by Ca2+ ionophore ionomycin (1 µM and by store depletion with the sarcoendoplasmatic Ca2+ ATPase inhibitor thapsigargin (1 µM. However, Orai1 protein abundance at the platelet surface was not significantly affected by ionomycin and only slightly increased by thapsigargin. The effect of thrombin and CRP on Orai1 abundance and [Ca2+]i was significantly blunted by Rac1 inhibitor NSC23766 (50 µM. Conclusion: The increase of [Ca2+]i following stimulation of platelets with thrombin and collagen related peptide is potentiated by ultrarapid Rac1 sensitive translocation of Orai1 into the cell membrane.

Fabrication of new carbon paste electrodes based on gold nano-particles self-assembled to mercapto compounds as suitable ionophores for potentiometric determination of copper ions

Directory of Open Access Journals (Sweden)

Rasoul Pourtaghavi Talemi

2013-12-01

Full Text Available In the present study, we investigate the potentiometric behavior of Cu2+ carbon paste electrodes based on two mercapto compounds 2-ethylmino-5-mercapto-1,3,4-thiadiazole (EAMT and 2-acetylamino-5-mercapto-1,3,4-thiadiazole (AAMT self-assembled on gold nano-paricle (GNP as ionophore. Then, the obtained results from the modified electrodes are compared. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu2+, in which the sulfur and nitrogen atoms in their structure play a significant role as the effective coordination donor site for the copper ion. Among these electrodes, the best performance was obtained with the sensor with a EAMT/graphite powder/paraffin oil weight ratio of 4.0/68/28 with 200 µL of GNP which exhibits the working concentration range of 1.6×10−9 to 6.3×10−2 M and a nernstian slope of 28.9±0.4 mVdecade−1 of copper(II activity. The detection limit of electrode was 2.9(±0.2×10−10M and potential response was pH ; in other words, it was independent across the range of 2.8–6.3. The proposed electrode presented very good selectivity and sensitivity towards the Cu2+ ions over a wide variety of cations including alkali, alkaline earth, transition and heavy metal ions. Moreover, the proposed electrode was successfully applied as an indicator electrode in the potentiometric titration of Cu(II ions with EDTA and also the potentiometric determination of copper ions in spiked water samples.

Artificial oocyte activation with calcium ionophore for frozen sperm cycles.

Science.gov (United States)

Karabulut, Seda; Aksünger, Özlem; Ata, Can; Sağıroglu, Yusuf; Keskin, İlknur

2018-04-05

Fertilization problems are the major problems that may be faced in 30-55% of the patients during an intracytoplasmic sperm injection (ICSI) cycle. A successful oocyte activation depends on factors related to both sperm and oocyte, and one of the important factors that mediates the process is Ca 2+ concentration within the oocyte. Artificial oocyte activation (AOA) is a method used for fertilization problems that commonly involve the usage of Ca 2+ ionophores and is usually used in problems such as total fertilization failure (TFF) and globozoospermia. The aim of the present study was to investigate possible effects of AOA for different groups of patients with fertilization failure. Four groups of patients (previous TFF, low oocyte number, severe sperm quality, and frozen sperm (FS) group) that underwent ICSI with AOA were included in the study. All groups had similar control groups with same indications except TFF, where AOA was not performed. Fertilization rates were significantly higher in the TFF group than those observed in other AOA groups. Fertilization rates and quality of embryos observed in the remaining AOA groups were higher than those of the controls, which were statistically insignificant. Prgenancy rates were higher in all AOA groups compared to the controls, although the differences were significant in FS group only. Quality of embryos and pregnancy rates were lower in the TFF group compared to the remaining AOA groups indicating possible concomitant problems. Fertilization rates, quality of embryos and pregnancy rates seemed to be increased in all indication groups suggesting that not only TFF patients but also a wide variety of patients with different indications may benefit from AOA. ICSI: Intracytoplasmic sperm injection; ARTs: Assisted reproductive techniques; Ca: Calcium; AOA: Artificial oocyte activation; TFF: Total fertilization failures; OAT: Oligoasthenoteratozoospemia; IVF: In vitro fertilization; SOAT: Severe OAT; LON: Low ooctye number

Imbalance of plasma membrane ion leak and pump relationship as a new aetiological basis of certain disease states.

Science.gov (United States)

Ronquist, G; Waldenström, A

2003-12-01

amyloid peptide during the development of Alzheimer's disease is one of several mechanisms proposed to account for the toxicity of this peptide on neuronal membranes. We have studied the effects of the peptide and fragments thereof on 45Ca2+-uptake in human erythrocytes and the energetic consequences. Treatment of erythrocytes with the beta 1-40 peptide, results in qualitatively similar nucleotide pattern and decrease of energy charge as the treatment with Ca2+-ionophore A23187. Finally, in recent studies we have revealed and published in this journal that a rare condition, Tarui's disease or glycogenosis type VII, primarily associated with a defect M-subunit of phosphofructokinase, demonstrates as a cophenomenon an increased leak of Ca2+ into erythrocytes.

A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

Science.gov (United States)

Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

2016-10-01

The solid-state pH electrode has the potential possibility to be used in many extreme situations with satisfactory accuracy and low cost. But its performance is affected by the solid electrolyte, preparation process, and the structure of the sensitive membrane, etc. In this work, the relationships between these factors and the characteristic of the prepared electrode were verified by controlling the preparation conditions with a variety of electrochemical methods. Firstly, the solid electrolyte poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) was electrochemically deposited on the screen-printed carbon electrode (SPCE) substrate by a potentiostatic method in an aqueous solution containing 0.01 M 3,4-ethylenedioxythiophene (EDOT) and 0.1 M polystyrene sulfonic (PSS) acid as the supporting electrolyte. The PEDOT films were then characterized by cyclic voltammetry (CV) in the 0.1 M NaNO3 aqueous solution in order to obtain the optimized polymerization potential and charges where the PEDOT film would have a higher redox capacitance. Finally, the pH electrode was prepared by coating the SPCE/PEDOT(PSS) with a plasticized polyvinyl chloride (PVC) membrane containing tridodecylamine as hydrogen ionophore manually, and experiments were carried out to study the effect of the usage of PVC per square millimeter on the response time and stability of the electrode to optimize the PVC film thickness. The potentiometric response of the pH electrode was studied in the buffer solutions with pH ranging from 5.00 to 10.81 by the open-circuit potential (OCP) method. Experimental results show that the sensitivity of the electrode is  -55.7  ±  0.5 mV pH-1 (r 2  >  0.9980) at room temperature (24  ±  1 °C) with pH ranging from 2.00-10.50, approximating to the theoretical nernstian slope (-59.16 mV pH-1),and the response time was less than 10 s. Moreover, it has low impedance, high accuracy and potential stability as well as some

A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

International Nuclear Information System (INIS)

Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

2016-01-01

The solid-state pH electrode has the potential possibility to be used in many extreme situations with satisfactory accuracy and low cost. But its performance is affected by the solid electrolyte, preparation process, and the structure of the sensitive membrane, etc. In this work, the relationships between these factors and the characteristic of the prepared electrode were verified by controlling the preparation conditions with a variety of electrochemical methods. Firstly, the solid electrolyte poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) was electrochemically deposited on the screen-printed carbon electrode (SPCE) substrate by a potentiostatic method in an aqueous solution containing 0.01 M 3,4-ethylenedioxythiophene (EDOT) and 0.1 M polystyrene sulfonic (PSS) acid as the supporting electrolyte. The PEDOT films were then characterized by cyclic voltammetry (CV) in the 0.1 M NaNO3 aqueous solution in order to obtain the optimized polymerization potential and charges where the PEDOT film would have a higher redox capacitance. Finally, the pH electrode was prepared by coating the SPCE/PEDOT(PSS) with a plasticized polyvinyl chloride (PVC) membrane containing tridodecylamine as hydrogen ionophore manually, and experiments were carried out to study the effect of the usage of PVC per square millimeter on the response time and stability of the electrode to optimize the PVC film thickness. The potentiometric response of the pH electrode was studied in the buffer solutions with pH ranging from 5.00 to 10.81 by the open-circuit potential (OCP) method. Experimental results show that the sensitivity of the electrode is  −55.7  ±  0.5 mV pH −1 ( r 2   >  0.9980) at room temperature (24  ±  1 °C) with pH ranging from 2.00–10.50, approximating to the theoretical nernstian slope (−59.16 mV pH −1 ),and the response time was less than 10 s. Moreover, it has low impedance, high accuracy and potential stability

Luteolin, a flavonoid, inhibits CD40 ligand expression by activated human basophils.

Science.gov (United States)

Hirano, Toru; Arimitsu, Junsuke; Higa, Shinji; Naka, Tetsuji; Ogata, Atsushi; Shima, Yoshihito; Fujimoto, Minoru; Yamadori, Tomoki; Ohkawara, Tomoharu; Kuwabara, Yusuke; Kawai, Mari; Kawase, Ichiro; Tanaka, Toshio

2006-01-01

We have previously shown that flavonoids such as luteolin, apigenin and fisetin inhibit interleukin 4 and interleukin 13 production. In this study, we investigated whether luteolin can suppress CD40 ligand expression by basophils. A human basophilic cell line, KU812, was stimulated with A23187 and phorbol myristate acetate (PMA) with or without various concentrations of luteolin or other flavonoids for 12 h, and CD40 ligand expression was analyzed by FACS. The effect of luteolin on CD40 ligand mRNA expression was studied by semiquantitative reverse transcription PCR analysis. In addition, CD40 ligand expression was also measured in purified basophils that had been stimulated for 12 h with A23187 plus PMA with or without various concentrations of luteolin. CD40 ligand expression by KU812 cells was enhanced noticeably in response to A23187 and even more strikingly augmented by A23187 plus PMA. The expression was significantly suppressed by 10 or 30 microM of luteolin, whereas myricetin failed to inhibit. Reverse transcription PCR analyses demonstrated that luteolin inhibited CD40 ligand mRNA expression by stimulated KU812 cells. Of the six flavonoids examined, luteolin, apigenin, fisetin and quercetin at 30 microM showed a significant inhibitory effect on CD40 ligand expression. The incubation of purified basophils with A23187 plus PMA significantly enhanced CD40 ligand expression, and the presence of luteolin again had an inhibitory effect. Luteolin inhibits CD40 ligand expression by activated basophils.

Enhanced incorporation of radioactive inorganic phosphate into phospholipids of HeLa cells by tumor promoters

International Nuclear Information System (INIS)

Nishino, H.; Fujiki, H.; Terada, M.; Sato, S.

1983-01-01

Teleocidin, a new tumor promoter, increased incorporation of radioactive inorganic phosphate ( 32 P/sub i/) into phospholipids in HeLa cells. This effect was detected within 1 h on incubation of the cells in medium containing teleocidin. The half-maximum effective dose of teleocidin was approximately 10 ng/ml. The main effect of teleocidin was on the incorporation of 32 P/sub i/ into the phosphatidylcholine fraction, with a lesser effect on 32 P/sub i/ incorporation into other phospholipid fractions. Increased incorporation of 32 P/sub i/ into phospholipids was also observed on incubation of the cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), dihydroteleocidin B, or lyngbyatoxin A, which are all complete tumor promoters, and also with mezerein, which is an incomplete and second stage promoter. On the other hand, at concentrations of up to 1 microgram/ml, 4-O-methyl TPA and C/sub a/ 2 + ionophore A23187, which are incomplete and first stage promoters, and phorbol, which has no promoting activity in skin carcinogenesis, did not cause any increased incorporation of 32 P/sub i/ into phospholipid fractions of HeLa cells

Protection against oxidant-induced apoptosis by mitochondrial thioredoxin in SH-SY5Y neuroblastoma cells

International Nuclear Information System (INIS)

Chen Yan; Yu Min; Jones, Dean P.; Greenamyre, J. Timothy; Cai Jiyang

2006-01-01

Mitochondrial oxidative stress plays important roles in aging and age-related degenerative disorders. The newly identified mitochondrial thioredoxin (mtTrx; Trx2) is a key component of the mitochondrial antioxidant system which is responsible for the clearance of reactive intermediates and repairs proteins with oxidative damage. Here, we show that in cultured SH-SY5Y human neuroblastoma 1cells, overexpression of mtTrx inhibited apoptosis and loss of mitochondrial membrane potential induced by a chemical oxidant, tert-butylhydroperoxide (tBH). The effects of calcium ionophore (Br-A23187) were not affected by mtTrx, suggesting the protection was specific against oxidative injury. The mitochondrial glutathione pool was oxidized by tBH, and this oxidation was not inhibited by increased mtTrx. Consequently, the antioxidant function of mtTrx is not redundant, but rather in addition, to that of GSH. Mutations of Cys90 and Cys93 to serines rendered mtTrx ineffective in protection against tBH-induced cytoxicity. These data indicate that mtTrx controls the mitochondrial redox status independently of GSH and is a key component of the defensive mechanism against oxidative stress in cultured neuronal cells

Impaired phagocytosis in localized aggressive periodontitis: rescue by Resolvin E1.

Directory of Open Access Journals (Sweden)

Gabrielle Fredman

Full Text Available Resolution of inflammation is an active temporally orchestrated process demonstrated by the biosynthesis of novel proresolving mediators. Dysregulation of resolution pathways may underlie prevalent human inflammatory diseases such as cardiovascular diseases and periodontitis. Localized Aggressive Periodontitis (LAP is an early onset, rapidly progressing form of inflammatory periodontal disease. Here, we report increased surface P-selectin on circulating LAP platelets, and elevated integrin (CD18 surface expression on neutrophils and monocytes compared to healthy, asymptomatic controls. Significantly more platelet-neutrophil and platelet-monocyte aggregates were identified in circulating whole blood of LAP patients compared with asymptomatic controls. LAP whole blood generates increased pro-inflammatory LTB4 with addition of divalent cation ionophore A23187 (5 µM and significantly less, 15-HETE, 12-HETE, 14-HDHA, and lipoxin A(4. Macrophages from LAP subjects exhibit reduced phagocytosis. The pro-resolving lipid mediator, Resolvin E1 (0.1-100 nM, rescues the impaired phagocytic activity in LAP macrophages. These abnormalities suggest compromised resolution pathways, which may contribute to persistent inflammation resulting in establishment of a chronic inflammatory lesion and periodontal disease progression.

Comparison of the effect of timegadine, levamisole, and D-penicillamine on human neutrophil metabolism of endogenous arachidonic acid and chemotaxis

Energy Technology Data Exchange (ETDEWEB)

Nielsen, O.H.; Ahnfelt-Roenne, I. Department of Pharmacology, Leo Pharmaceutical Products, Ballerup; Elmgreen, J.

1988-01-01

The effect of timegadine, a novel experimental antirheumatic drug, on human neutrophil (PMN) 5-lipoxygenase activity and leukotriene B/sub 4/ (LTB/sub 4/) chemotaxis was compared with that of two second-line antiinflammatory drugs, D-penicillamine and levamisole. 1-/sup 14/C-Arachidonic acid (AA) was incorporated into the purified cells until steady state conditions were obtained. After preincubation with serial dilutions of the three drugs, AA release and metabolism was stimulated with calcium ionophore A23187. The radioactive eicosanoids released were extracted and separated by thinlayer chromatography, followed by autoradiography and quantitative laser densitometry. Chemotaxi of PMNs towards LTB/sub 4/ was measured in a modified Boyden chamber. Timegardine showed dose-dependent inhibition of both the 5-lipoxygenase pathway (IC50 3.4 x 10/sup -5/ M), and of chemotaxis (IC50 3 x 10/sup -4/ M). Inhibition of the release of AA from phospholipids, however, occurred only at therapeutically irrelevant doses (millimolar concentrations). Levamisole and D-penicillamine did not inhibit any of the cell functions investigated. Inhibition of both neutrophil motility and cellular synthesis of pro-inflammatory eicosanoids, may thus contribute to the clinical effects of timegadine in rheumatoid arthritis.

Role of calcium in the dopaminergic effect on the proximal convoluted tubule of rat kidney

International Nuclear Information System (INIS)

Chan, Y.L.; Chatsudthipong, V.; Su-Tsai, S.M.; von Riotte, A.

1986-01-01

Microperfusion studies have shown that dopamine inhibits fluid and bicarbonate absorption in the rate proximal tubule. These studies are designed to examine the cellular mechanism underlying the proximal cellular response to dopamine action. In the isolated proximal cells, dopamine, in the concentration of 10 -6 M or less, had no effect on cAMP production. However, dopamine could increase cytosolic calcium concentration (from 90 nM to 210 nM) as measured by fluorospectrometry with fura-2 as a calcium indicator. Ca-45 flux studies have shown that dopamine could increase initial influx but not the steady state uptake of Ca. Dopamine could also increase efflux of Ca. In situ microperfusion of proximal tubule and peritubular capillaries has demonstrated that Ca ionophore, A23187 (10 -6 M), could simulate the inhibitory effects of dopamine on fluid and biocarbonate absorption. There was no additive effect observed when both agents were added together in the capillary perfusate. Removal of calcium from the perfusate could partially blunt the effect of dopamine. These results suggest that intracellular calcium plays a crucial role in the dopaminergic regulation of proximal tubular transport

Expression, Localization of SUMO-1, and Analyses of Potential SUMOylated Proteins in Bubalus bubalis Spermatozoa.

Science.gov (United States)

Brohi, Rahim Dad; Wang, Li; Hassine, Najla Ben; Cao, Jing; Talpur, Hira Sajjad; Wu, Di; Huang, Chun-Jie; Rehman, Zia-Ur; Bhattarai, Dinesh; Huo, Li-Jun

2017-01-01

Mature spermatozoa have highly condensed DNA that is essentially silent both transcriptionally and translationally. Therefore, post translational modifications are very important for regulating sperm motility, morphology, and for male fertility in general. Protein sumoylation was recently demonstrated in human and rodent spermatozoa, with potential consequences for sperm motility and DNA integrity. We examined the expression and localization of small ubiquitin-related modifier-1 (SUMO-1) in the sperm of water buffalo ( Bubalus bubalis ) using immunofluorescence analysis. We confirmed the expression of SUMO-1 in the acrosome. We further found that SUMO-1 was lost if the acrosome reaction was induced by calcium ionophore A23187. Proteins modified or conjugated by SUMO-1 in water buffalo sperm were pulled down and analyzed by mass spectrometry. Sixty proteins were identified, including proteins important for sperm morphology and motility, such as relaxin receptors and cytoskeletal proteins, including tubulin chains, actins, and dyneins. Forty-six proteins were predicted as potential sumoylation targets. The expression of SUMO-1 in the acrosome region of water buffalo sperm and the identification of potentially SUMOylated proteins important for sperm function implicates sumoylation as a crucial PTM related to sperm function.

Expression, Localization of SUMO-1, and Analyses of Potential SUMOylated Proteins in Bubalus bubalis Spermatozoa

Directory of Open Access Journals (Sweden)

Rahim Dad Brohi

2017-06-01

Full Text Available Mature spermatozoa have highly condensed DNA that is essentially silent both transcriptionally and translationally. Therefore, post translational modifications are very important for regulating sperm motility, morphology, and for male fertility in general. Protein sumoylation was recently demonstrated in human and rodent spermatozoa, with potential consequences for sperm motility and DNA integrity. We examined the expression and localization of small ubiquitin-related modifier-1 (SUMO-1 in the sperm of water buffalo (Bubalus bubalis using immunofluorescence analysis. We confirmed the expression of SUMO-1 in the acrosome. We further found that SUMO-1 was lost if the acrosome reaction was induced by calcium ionophore A23187. Proteins modified or conjugated by SUMO-1 in water buffalo sperm were pulled down and analyzed by mass spectrometry. Sixty proteins were identified, including proteins important for sperm morphology and motility, such as relaxin receptors and cytoskeletal proteins, including tubulin chains, actins, and dyneins. Forty-six proteins were predicted as potential sumoylation targets. The expression of SUMO-1 in the acrosome region of water buffalo sperm and the identification of potentially SUMOylated proteins important for sperm function implicates sumoylation as a crucial PTM related to sperm function.

Immobilization of tris(2 pyridyl methylamine in a PVC-Membrane Sensor and Characterization of the Membrane Properties

Directory of Open Access Journals (Sweden)

Rezayi Majid

2012-05-01

Full Text Available Abstract Background Due to the increasing industrial use of titanium compounds, its determination is the subject of considerable efforts. The ionophore or membrane active recognition is the most important component of any polymeric membrane sensor. The sensor’s response depends on the ionophore and bonding between the ionophore and the target ion. Ionophores with molecule-sized dimensions containing cavities or semi-cavities can surround the target ion. The bond between the ionophore and target ion gives different selectivity and sensitivity toward the other ions. Therefore, ionophores with different binding strengths can be used in the sensor. Results In the present work, poly (vinyl chloride (PVC based membrane incorporating tris (2 pyridyl methylamine (tpm as an ionophore has been prepared and explored as a titanium(III selective sensor. Conclusions The strengths of the ion–ionophore (Ti(OH2+-tpm interactions and the role of ionophore on membrane were tested by various techniques such as elemental analysis, UV–vis, Fourier transform infrared (FTIR spectroscopy, scanning electron microscopy (SEM, and powder X-ray diffraction (XRD. All data approved the successful incorporation of organic group via covalent bond.

Development of a sensitive and specific radioreceptor assay for leukotriene B4

International Nuclear Information System (INIS)

Kohi, F.; Agrawal, D.K.; Cheng, J.B.; Bewtra, A.; Townley, R.G.; Olesch, J.W.

1988-01-01

To establish a simple and sensitive quantitation of leukotriene B 4 (LTB 4 ), they developed a radioreceptor assay (RRA) using a highly specific [ 3 H]leukotriene B 4 ([ 3 H]LTB 4 ) binding to a guinea pig spleen homogenate. The assay detected LTB 4 levels as low as 0.12 pmol per tube. 50% inhibition of bound [ 3 H]LTB 4 was obtained by 2.5 nM of unlabeled LTB 4 . [ 3 H]LTB 4 competition studies indicated that 20-hydroxy-LTB 4 was 8 times, 6 trans-LTB 4 was 640 times and 20-carboxy-LTB 4 was 1000 times less effective than LTB 4 . The peptide leukotrienes C 4 , D 4 and E 4 showed no effect on [ 3 H]LTB 4 binding. Recovery rates averaged 97% after ethanol extraction and evaporation of known amounts of LTB 4 . The intra-assay coefficients of variation for three samples were 2.4%, 7.2% and 8.4%, respectively. This assay was validated by measuring LTB 4 released from human granulocytes stimulated with calcium ionophore A23187. The LTB 4 level was maximal at 10 min and decreased rapidly after 15 min. This radioreceptor assay for leukotriene B 4 is highly sensitive and is comparable to the reported sensitivity by radioimmunoassay. The method is simpler and less expensive than other methods such as high pressure liquid chromatography and is suitable for routine measurement of leukotriene B 4

Gamma irradiation enhances biological activities of mulberry leaf extract

International Nuclear Information System (INIS)

Cho, Byoung-Ok; Che, Denis Nchang; Yin, Hong-Hua; Jang, Seon-Il

2017-01-01

The purpose of this study was to investigate the influence of irradiation on the anti-oxidative, anti-inflammatory and whitening effects of mulberry leaf extract. This was done by comparing the phenolic contents; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effects; 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) radical scavenging effects; in vitro tyrosinase inhibitory effects and the production of IL-6, TNF-α, PGE 2 , and NO in lipopolysaccharide-stimulated RAW264.7 macrophages and the production of IL-6 and TNF-α in phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated HMC-1 cells, respectively. The results showed that irradiated mulberry leaf extract possesses more anti-oxidant, anti-inflammatory, and tyrosinase inhibitory activities than their non-irradiated counterpart, probably due to increase in phenolic contents induced by gamma irradiation at dose of 10kGy. This research stresses on the importance of irradiation in functional foods. - Highlights: • Gamma-irradiated mulberry leaf extract enhanced in vitro antioxidant activities. • Gamma-irradiated mulberry leaf extract enhanced in vitro tyrosinase inhibitory effects. • Gamma-irradiated mulberry leaf extract treatment reduced the production of IL-6, TNF-α, PGE 2 , and NO.

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

Directory of Open Access Journals (Sweden)

Wolfgang Hüttel

2014-02-01

Full Text Available Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L−1 dehydroxymonensin; ΔmonE: 0.50 g L−1 demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L−1 dehydroxydemethylmonensin. Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation.

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding.

Science.gov (United States)

Hüttel, Wolfgang; Spencer, Jonathan B; Leadlay, Peter F

2014-01-01

Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L(-1) dehydroxymonensin; ΔmonE: 0.50 g L(-1) demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L(-1) dehydroxydemethylmonensin). Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation.

Francisella tularensis Catalase Restricts Immune Function by Impairing TRPM2 Channel Activity.

Science.gov (United States)

Shakerley, Nicole L; Chandrasekaran, Akshaya; Trebak, Mohamed; Miller, Barbara A; Melendez, J Andrés

2016-02-19

As an innate defense mechanism, macrophages produce reactive oxygen species that weaken pathogens and serve as secondary messengers involved in immune function. The Gram-negative bacterium Francisella tularensis utilizes its antioxidant armature to limit the host immune response, but the mechanism behind this suppression is not defined. Here we establish that F. tularensis limits Ca(2+) entry in macrophages, thereby limiting actin reorganization and IL-6 production in a redox-dependent fashion. Wild type (live vaccine strain) or catalase-deficient F. tularensis (ΔkatG) show distinct profiles in their H2O2 scavenging rates, 1 and 0.015 pm/s, respectively. Murine alveolar macrophages infected with ΔkatG display abnormally high basal intracellular Ca(2+) concentration that did not increase further in response to H2O2. Additionally, ΔkatG-infected macrophages displayed limited Ca(2+) influx in response to ionomycin, as a result of ionophore H2O2 sensitivity. Exogenously added H2O2 or H2O2 generated by ΔkatG likely oxidizes ionomycin and alters its ability to transport Ca(2+). Basal increases in cytosolic Ca(2+) and insensitivity to H2O2-mediated Ca(2+) entry in ΔkatG-infected cells are reversed by the Ca(2+) channel inhibitors 2-aminoethyl diphenylborinate and SKF-96365. 2-Aminoethyl diphenylborinate but not SKF-96365 abrogated ΔkatG-dependent increases in macrophage actin remodeling and IL-6 secretion, suggesting a role for H2O2-mediated Ca(2+) entry through the transient receptor potential melastatin 2 (TRPM2) channel in macrophages. Indeed, increases in basal Ca(2+), actin polymerization, and IL-6 production are reversed in TRPM2-null macrophages infected with ΔkatG. Together, our findings provide compelling evidence that F. tularensis catalase restricts reactive oxygen species to temper macrophage TRPM2-mediated Ca(2+) signaling and limit host immune function. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

In vitro effect of pH on resistance of ruminal bacteria to intracellular potassium depletion, and effect of pH and ionophores on ammonia and microbial protein production Efeito do pH in vitro sobre a resistência de bactérias do rúmen à perda de potássio intracelular e efeito do pH e de ionóforos sobre a produção de amônia e proteína microbiana

Directory of Open Access Journals (Sweden)

W.M. Leopoldino

2005-12-01

Full Text Available Ruminal fluid from steers fed on pasture was incubated with artificial media at pH 5.5 and 7.0 in two experiments. In the first, the effect of monensin level on resistance of ruminal bacteria to potassium depletion was evaluated; in the second, effects of the ionophores monensin and lasalocid on ammonia and protein production were quantified. In experiment 1, culture media affected potassium level. The monensin concentration needed to cause half maximal potassium depletion was 2.77µM at pH 5.5 but was 0.056µM at pH 7.0, showing that bacteria incubated at pH 5.5 were more tolerant to monensin than those incubated at pH 7.0. Both ionophores as well as increased acidity caused decreased ammonia production. Both ionophores inhibited ammonia production by 56%, independently of pH. In cultures incubated at pH 5.5 compared to pH 7.0, ammonia production was decreased by 50.5%, independently of the ionophores. Therefore, effects of ionophores and acidity were additive, and the maximum inhibition occurred in the presence of an ionophore at low pH (75.2%. Microbial protein production was lowest when lasalocid was present in a low pH culture medium, causing inhibition of microbial growth.Em dois estudos, o líquido ruminal de bovinos mantidos sob pastagem foi usado para incubação in vitro em diferentes meios artificiais com valores de pH 5,5 e 7,0, para avaliar a ação de níveis crescentes de monensina na resistência à perda de potássio de bactérias do rúmen e verificar o efeito de monensina e lasalocida na produção de amônia e de proteína microbiana em pH 5,5 e 7,0. O meio utilizado para determinar a perda de potássio interferiu nos valores absolutos de potássio. A concentração de monensina necessária para causar a metade da perda máxima de potássio foi de 2,77µM em pH 5,5 e 0,056µM em pH 7,0, evidenciando que as bactérias incubadas em meios com pH 5,5 foram mais resistentes à monensina que aquelas incubadas em meios com pH 7

Effects of carnitine and its congeners on eicosanoid discharge from rat cells: implications for release of TNFα

Directory of Open Access Journals (Sweden)

Ingrid M. Garrelds

1993-01-01

Full Text Available THE acyl carrier coenzyme A (CoA is involved in fatty acid metabolism. The carnitine/CoA ratio is of particular importance in regulating the transport of long-chain fatty acids into mitochondria for oxidation. Also CoA has a role in the formation and breakdown of products from both the cyclooxygenase and lipoxygenase pathways of the precursor arachidonic acid. In the present study the effect of 4 days feeding of 300 mg/kg/day of L-carnitine, acetyl Lcarnitine and propionyl L-carnitine on the basal and calcium ionophore (A23187 stimulated release of arachidonic acid metabolites from rat carrageenin elicited peritoneal cells was investigated. There were two series of experiments carried out. In the first, the harvested peritoneal cell population consisted of less than 90% macrophages and additional polymorphonuclear (PMN leucocytes. The basal release of prostaglandin E2 (PGE2, 6-ketoprostaglandin F1α (6-keto-PGF1α and leukotriene B4 (LTB4 was stimulated by all treatments. The A23187 stimulated release of 6-keto-PGF1α and LTB4 was increased by all three compounds. The 6-keto-PGF1α:TxB2 and 6-keto-PGF1α:LTB4 ratios were increased by carnitine treatment. These results suggested that carnitine could modify the macrophage component of an inflammatory site in vivo. In the second series of experiments the harvested cell population was highly purified (>95% macrophages and none of the compounds fed to the rats caused a change of either eicosanoid or TNFα formation. Moreover the 6-keto-PGF1α:TxB2 and 6-keto-PGF1α:LTB4 ratios were not enhanced by any of the compounds tested. It is conceivable that in the first series the increased ratios 6-keto-PGF1α:TxB2 and 6-keto-PGF1α:LTB4 reflected the effect of carnitine or its congeners on PMN leucocytes rather than on macrophages.

A calixarene-based ion-selective electrode for thallium(I) detection

International Nuclear Information System (INIS)

Chester, Ryan; Sohail, Manzar; Ogden, Mark I.; Mocerino, Mauro; Pretsch, Ernö; De Marco, Roland

2014-01-01

Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl + ionophores have been utilized in Tl + ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10 −2 –10 −6 M TlNO 3 with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β IL ) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn 2+ , Ca 2+ , Ba 2+ , Cu 2+ , Cd 2+ and Al 3+ with moderate selectivity against Pb 2+ , Li + , Na + , H + , K + , NH 4 + and Cs + , noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade −1 and a lower detection limit of 30.2 nM. Due to the presence of an undesirable

Proanthocyanidin-rich Pinus radiata bark extract inhibits mast cell-mediated anaphylaxis-like reactions.

Science.gov (United States)

Choi, Yun Ho; Song, Chang Ho; Mun, Sung Phil

2018-02-01

Mast cells play a critical role in the effector phase of immediate hypersensitivity and allergic reactions. Pinus radiata bark extract exerts multiple biological effects and exhibits immunomodulatory and antioxidant properties. However, its role in mast cell-mediated anaphylactic reactions has not been thoroughly investigated. In this study, we examined the effects of proanthocyanidin-rich water extract (PAWE) isolated from P. radiata bark on compound 48/80-induced or antidinitrophenyl (DNP) immunoglobulin E (IgE)-mediated anaphylaxis-like reactions in vivo. In addition, we evaluated the mechanism underlying the inhibitory effect of PAWE on mast cell activation, with a specific focus on histamine release, using rat peritoneal mast cells. PAWE attenuated compound 48/80-induced or anti-DNP IgE-mediated passive cutaneous anaphylaxis-like reactions in mice, and it inhibited histamine release triggered by compound 48/80, ionophore A23187, or anti-DNP IgE in rat peritoneal mast cells in vitro. Moreover, PAWE suppressed compound 48/80-elicited calcium uptake in a concentration-dependent manner and promoted a transient increase in intracellular cyclic adenosine-3',5'-monophosphate levels. Together, these results suggest that proanthocyanidin-rich P. radiata bark extract effectively inhibits anaphylaxis-like reactions. Copyright © 2017 John Wiley & Sons, Ltd.

Equine tracheal epithelial membrane strips - An alternate method for examining epithelial cell arachidonic acid metabolism

International Nuclear Information System (INIS)

Gray, P.R.; Derksen, F.J.; Robinson, N.E.; Peter-Golden, M.L.

1990-01-01

Arachidonic acid metabolism by tracheal epithelium can be studied using enzymatically dispersed cell suspensions or cell cultures. Both techniques require considerable tissue disruption and manipulation and may not accurately represent in vivo activity. The authors have developed an alternate method for obtaining strips of equine tracheal epithelium without enzymatic digestion. In the horse, a prominent elastic lamina supports the tracheal epithelium. By physical splitting this lamina, they obtained strips (≤12 x 1.5 cm) of pseudostratified columnar epithelium attached to a layer of elastic tissue 30-100 μm thick. Epithelial strips (1.2 x 0.5 cm) were attached to plexiglass rods and incubated with [ 3 H]arachidonic acid in M199 medium (0.5 μCi/ml) for 24 hours at 37C. The strips incorporated 36±4% (mean ± SEM) of the total radioactivity and released 8.0±1.2% of incorporated radioactivity when stimulated by 5.0 μM calcium ionophore A23187. The extracted supernatant was processed using HPLC, resulting in peaks of radioactivity that co-eluted with authentic PGE 2 , PGF 2 α, and 12-HETE standards. The greatest activity corresponded to the PGE 2 and PGF 2 α standards, which is a similar pattern to that reported for cultured human tracheal epithelium

Isolation and characterization of plasma membranes from guinea pig ileum

International Nuclear Information System (INIS)

Anon.

1986-01-01

A plasma membrane fraction from guinea pig ileum has been isolated by extraction of a crude microsomal fraction with a low ionic strength buffer containing ATP and Ca 2+ . The extracted microsomes were subjected to sucrose-density-gradient centrifugation in the presence of 0.6 M KCl. The plasma membranes were substantially free from contamination with contractile proteins, mitochondria and sarco-plasmic reticulum. The plasma membrane vesicles were enriched 30-to-40-fold in Na + -K + -ATPase and 5'-nucleotidase activities. The plasma membrane vesicles accumulated Ca 2+ in the presence of ATP. The addition of Ca 2+ ionophore A23187 to vesicles loaded with Ca 2+ in the presence of ATP removed Ca 2+ completely from the vesicles in one minute. The Km values for the Ca 2+ -dependent phosphorylated intermediates of Ca 2+ -Mg 2+ -ATPase and Ca 2+ uptake were approximately 0.8 μM indicating that the phosphorylated intermediates represent phosphorylation of Ca 2+ pump ATPase. The 3 H-nitrendipine binding to plasma membranes was characterized by high affinity with Kd of 185 pM and B/sub max/ 1280 fmol/mg protein. The plasma membrane vesicles prepared by these procedures can prove useful for the study of ion transport

Functional reconstitution of an ATP-driven Ca2+-transport system from the plasma membrane of Commelina communis L

International Nuclear Information System (INIS)

Graef, P.; Weiler, E.W.

1990-01-01

The protein(s) that constitute(s) the ATP-driven Ca 2+ -translocator of plasma membrane enriched vesicles obtained by aqueous two-phase partitioning from leaves of Commelina communis L. has/have been solubilized and reincorporated into tightly sealed liposomes. The reconstituted Ca 2+ -transport system was studied using ATP-driven 45 Ca 2+ import into the proteoliposomes as a measure of activity. The detergent, 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonate proved to be the most suitable and was used at 10 millimolar concentration, i.e. just above its critical micellar concentration. The presence of additional phospholipid and ATP improved the solubilization and/or reconstitution. The characteristics of the reconstituted system were similar to those of the plasma membrane-bound activity, including the apparent K m for Ca 2+ inhibition by relatively high levels of vanadate and lacking response to added calmodulin. The reconstituted transport system was very strongly inhibited by erythrosine B and had a low apparent K m for ATP levels of the Ca 2+ -ionophore A 23187 instantaneously discharged 90% of the Ca 2+ associated with the vesicles, proving that it had been accumulated in the intravesicular volume in soluble, freely exchangeable form. Ca 2+ -transport in the reconstituted system was thus primary active, through a Ca 2+ -translocating ATPase

Titanium (III) cation selective electrode based on synthesized tris(2pyridyl) methylamine ionophore and its application in water samples

Science.gov (United States)

Rezayi, Majid; Karazhian, Reza; Abdollahi, Yadollah; Narimani, Leila; Sany, Seyedeh Belin Tavakoly; Ahmadzadeh, Saeid; Alias, Yatimah

2014-04-01

The introduction of low detection limit ion selective electrodes (ISEs) may well pave the way for the determination of trace targets of cationic compounds. This research focuses on the detection of titanium (III) cation using a new PVC-membrane sensor based on synthesized tris(2pyridyl) methylamine (tpm) ionophore. The application and validation of the proposed sensor was done using potentiometric titration, inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS). The membrane sensor exhibited a Nernstian response to the titanium (III) cation over a concentration range of 1.0 × 10-6-1.0 × 10-2 M and pH range from 1-2.5. The Nernstian slope, the lower of detection (LOD), and the response time (t95%) of the proposed sensor were 29.17 +/- 0.24 mV/dec, 7.9 × 10-7 M, and 20 s, respectively. The direct determination of 4-39 μg/ml of titanium (III) standard solution showed an average recovery of 94.60 and a mean relative standard deviation of 1.8 at 100.0 μg/ml. Finally, the utilization of the electrodes as end-point indicators for potentiometric titration with EDTA solutions for titanium (III) sensor was successfully carried out.

A calixarene-based ion-selective electrode for thallium(I) detection

Energy Technology Data Exchange (ETDEWEB)

Chester, Ryan [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Sohail, Manzar [Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia); Ogden, Mark I.; Mocerino, Mauro [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Pretsch, Ernö [ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics (IBP), Universitätstrasse 16, CH-8092, Zürich (Switzerland); De Marco, Roland, E-mail: rdemarc1@usc.edu.au [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia)

2014-12-03

Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl{sup +} ionophores have been utilized in Tl{sup +} ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10{sup −2}–10{sup −6} M TlNO{sub 3} with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β{sub IL}) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn{sup 2+}, Ca{sup 2+}, Ba{sup 2+}, Cu{sup 2+}, Cd{sup 2+} and Al{sup 3+} with moderate selectivity against Pb{sup 2+}, Li{sup +}, Na{sup +}, H{sup +}, K{sup +}, NH{sub 4}{sup +} and Cs{sup +}, noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade

Development of 125I-leukotriene B4 radio-immunoassay and its clinical applications

International Nuclear Information System (INIS)

Wang Zhaoyue; He Yang; Chen Dechun; Ruan Changgeng

1992-11-01

LTB 4 was extracted from porcine blood with the help of HPLC. The antiserum was raised by immunizing rabbits with LTB 4 which has been conjugated with bovine serum albumin by mixed anhydride method method. The titer of the anti-body was 1:7000 and the affinity coefficient was 2.1 x 10 9 L/M. Its cross reactions with LTA 4 , LTC 4 , LTD 4 and other arachidonic acid metabolites were 0.4 ∼ 6.4%.The 125 I-histamine-LTB 4 was prepared by using chloramine T procedure. The minimum detectable limit was 25 pg/tube. The recovery rate was 84.2 ∼ 113%. The intra- and inter-assay coefficient of variation were 5.2% and 9.7% respectively. The amount of LTB 4 produced by normal human PMNL which were stimulated by ionophore A23187 and arachidonic acid was 695.5 ± 329.7 pg/10 6 cells. PMNL of patients with various acute leukemias and CML generated an increased quantities of LTB 4 , TXB 2 and 6-keto-PGF 1α . LTB 4 produced by PMNL also showed an increasing tendency in both cerebral thrombosis and acute myocardial infarction, but was not altered in cerebral hemorrhage of non-infarction coronary disease

Localisation of calcium-binding proteins in ram spermatozoa using the immunofluorescence technique

International Nuclear Information System (INIS)

Sabrina Sukardi; Watson, P.F.

2000-01-01

Localization of two calcium-binding proteins (proteins A and B) believed to be involve in membrane fusion on whole spermatozoa were carried out in two stages; before and after the acrosome reaction, the reaction being a prerequisite to fertilization. Determination of the acrosome reaction and sperm viability is carried out using fluorescent dyes i.e., FITC-conjugated Pisum sativum agglutinin (PSA) and propidium iodide (PI) respectively. Polyclonal antibodies were raised in rabbits. Ejaculated semen was diluted in buffer and loaded into tubes. Acrosome reaction was induced with calcium ionophore A23187 at 390 degree C. PI was added to the sub-samples at time 0 and 45 minutes. Excess PI, ionophore and seminal plasma was filtered out with a syringe. Smears were made on slides and air-dried. The cells were pemeabilised with ethanol and rinsed in PBS. Batch 1 slides were incubated with FITC-PSA in the dark while batch H slides were incubated in 1% sheep serum. Batch II slides were then rinsed in PBS twice and incubated in both antiserum and pre-immune serum (negative control). These slides were then incubated in FITC-conjugated secondary antibody (anti-rabbit IgG) and kept in the dark. After final washing and mounted, both batches of slides were viewed immediately using fluorescence microscope. Results obtained before acrosome reaction showed localization of both antibodies to the whole sperm head, along the midpiece and tail. The acrosomes were also intact and cells were viable. After the acrosome reaction, localization of both antibodies were observed at the post-acrosomal region, midpiece, tail and the equatorial segment with no binding to the acrosome. Cells were mainly acrosome-reacted and dying. No binding was observed with pre-immune serum. Results indicate that the antigens were present in the acrosome and the change in binding suggests that the antigens have been redistributed after commencement of the acrosome reaction. The findings suggest that the proteins

Epithelial cell specific properties and genetic complementation in a delta F508 cystic fibrosis nasal polyp cell line.

Science.gov (United States)

Kunzelmann, K; Lei, D C; Eng, K; Escobar, L C; Koslowsky, T; Gruenert, D C

1995-09-01

Analysis of vectorial ion transport and protein trafficking in transformed cystic fibrosis (CF) epithelial cells has been limited because the cells tend to lose their tight junctions with multiple subcultures. To elucidate ion transport and protein trafficking in CF epithelial cells, a polar cell line with apical and basolateral compartments will facilitate analysis of the efficacy of different gene therapy strategies in a "tight epithelium" in vitro. This study investigates the genotypic and phenotypic properties of a CF nasal polyp epithelial, delta F508 homozygote, cell line that has tight junctions pre-crisis. The cells (sigma CFNPE14o-) were transformed with an origin-of-replication defective SV40 plasmid. They develop transepithelial resistance in Ussing chambers and are defective in cAMP-dependent Cl- transport as measured by efflux of radioactive Cl-, short circuit current (Isc), or whole-cell patch clamp. Stimulation of the cells by bradykinin, histamine, or ATP seems to activate both K(+)- and Ca(+2)-dependent Cl- transport. Measurement of 36Cl- efflux following stimulation with A23187 and ionomycin indicate a Ca(+2)-dependent Cl- transport. Volume regulatory capacity of the cells is indicated by cell swelling conductance. Expression of the CF transmembrane conductance regulator mRNA was indicated by RT-PCR amplification. When cells are grown at 26 degrees C for 48 h there is no indication of cAMP-dependent Cl- as has been previously indicated in heterologous expression systems. Antibodies specific for secretory cell antigens indicate the presence of antigens found in goblet, serous, and mucous cells; in goblet and serous cells; or in goblet and mucous cells; but not antigens found exclusively in mucous or serous cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of phorbol 12-myristate 13-acetate and diacylglycerols on thromboxane A2-independent phospholipase A2 activation in collage-stimulated human platelets.

Science.gov (United States)

Reddy, S; Rao, G H; Murthy, M

1994-04-01

We investigated the priming effects of protein kinase C (PKC) activators such as phorbol 12-myristate 13-acetate (PMA), 1,2-DiC8 and OAG, and 1,3-DiC8 (a poor activator of PKC) on thromboxane A2 (TxA2)-independent phospholipase A2 (PLA2) activation in human platelets using collagen and A23187 as agonists. We measured PLA2 activation in collagen-stimulated platelets in the presence of BW755C, which abolished TxA2 synthesis, rise in cytosolic Ca2+, and aggregation. In the presence of PMA (50 nM), the amount of arachidonic acid (AA) released in platelets stimulated with collagen and A23187 represented 300% (13.85 nmol versus 4.5 nmol) and 400% (28 nmol versus 7 nmol) of controls (without PMA), respectively, while 1,2-DiC8, OAG, and 1,3-DiC8 increased TxA2-independent AA release by 50% in A23187-stimulated platelets and had no effect on the release of AA in collagen-stimulated platelets. Interestingly, 1,3-DiC8, which is a poor activator of PKC, was as effective as the other two DAGs (OAG and 1,2-DiC8) in priming TxA2-independent PLA2 activation, but was less effective than PMA in platelets stimulated with A23187. These results suggest that the TXA2-dependent IP3-mediated rise in cytosolic Ca2+ may not be obligatory for priming PLA2 activation in the presence of PMA in collagen-stimulated platelets. In contrast, 1,2-DiC8, OAG, and 1,3-DiC8 likely enhanced PLA2 activation via intracellular Ca2+ as they selectively affect this enzyme only in A23187-stimulated platelets. We also observed a significant increase in both saturated (palmitic and stearic acids) and unsaturated fatty acids (oleic and linoleic acids) in platelets stimulated by collagen or A23187 in the presence of PMA (50 nM), but not in the presence of DAGs. These findings imply that PMA may also affect the activation of DAG/MAG lipases, PLA1, or nonspecific PLA2. Since both 1,2-DiC8 and OAG exert no significant effect on the release of these fatty acids, the effects observed with PMA on DAG lipase/PLA1 may not

DNA fragmentation and cell death mediated by T cell antigen receptor/CD3 complex on a leukemia T cell line.

Science.gov (United States)

Takahashi, S; Maecker, H T; Levy, R

1989-10-01

An anti-T cell receptor (TcR) monoclonal antibody (mAb), LC4, directed against a human leukemic T cell line, SUP-T13, caused DNA fragmentation ("apoptosis") and cell death upon binding to this cell line. Cross-linking of receptor molecules was necessary for this effect since F(ab')2, but not Fab', fragments of LC4 could induce cell death. Five anti-CD3 mAb tested also caused apoptosis, but only when they were presented on a solid phase. Interestingly, soluble anti-CD3 mAb induced calcium flux and had an additive effect on the calcium flux and interleukin 2 receptor expression induced by LC4, but these anti-CD3 mAb reversed the growth inhibition and apoptosis caused by LC4. The calcium ionophore A23187, but not the protein kinase C activator phorbol 12-myristate 13-acetate (PMA), also induced apoptosis, suggesting that protein kinase C activation alone does not cause apoptosis, although PMA is growth inhibitory. These results suggest that two distinct biological phenomena can accompany stimulation of the TcR/CD3 complex. In both cases, calcium flux and interleukin 2 receptor expression is induced, but only in one case is apoptosis and cell death seen. The signal initiating apoptosis can be selectively prevented by binding CD3 portion of the receptor in this cell line. This difference in signals mediated by the TcR/CD3 complex may be important in explaining the process of thymic selection, as well as in choosing anti-TcR mAb for therapeutic use.

The role of calcium in the receptor mediated control of potassium permeability in the rat lacrimal gland

International Nuclear Information System (INIS)

Parod, R.J.; Putney, J.W. Jr.

1978-01-01

In the presence of extracellular Ca, adrenaline stimulated by a large increase in the rate of K ( 86 Rb) release from rat lacrimal slices, followed by a lower, more sustained rate. In the absence of extracellular Ca, adrenaline elicited only a transient release of 86 Rb. The artificial introduction of Ca into the cytosol by the ionophore A-23187 could also initiate the release of 86 Rb. In a zero-Ca medium, if either adrenaline or carbachol produced a transient release of 86 Rb, the tissue could not respond to the other agonist with a transient release unless Ca was momentarily reintroduced to the medium. If Ca was present in a limiting concentration, the Ca-dependent rate of 86 Rb release elicited from a lacrimal slice exposed simultaneously to carbachol and adrenaline was not significantly different from the release seen with carbachol alone. It is concluded that the agonist-induced release of K from the lacrimal gland consists of both a Ca-independent phase which is initiated by the release of a limited pool of Ca, and a Ca-dependent phase which is mediated by the influx of extracellular Ca. It is also concluded that both α-adrenergic and muscarinic receptors occupation activate a common, post-receptor mechanism which may be responsible for both phases of K release. (author)

Dual optoelectronic visual detection and quantification of spectroscopically silent heavy metal toxins: A multi-measurand sensing strategy based on Rhodamine 6G as chromo or fluoro ionophore

Energy Technology Data Exchange (ETDEWEB)

Prathish, K.P.; James, D.; Jaisy, J. [Inorganic and Polymeric Materials Group, National Institute for Interdisciplinary Science and Technology (CSIR), Industrial Estate (P.O), Pappanamcode, Trivandrum 695019 (India); Prasada Rao, T., E-mail: rao@csrrltrd.ren.nic.in [Inorganic and Polymeric Materials Group, National Institute for Interdisciplinary Science and Technology (CSIR), Industrial Estate (P.O), Pappanamcode, Trivandrum 695019 (India)

2009-08-04

A novel colorimetric chemo-sensor for the simultaneous visual detection and quantification of spectroscopically silent heavy metal toxins viz. cadmium, lead and mercury has been developed. This is based on the proposed sequential ligand exchange (SLE) mechanism of iodide from Pb-I{sup -}-Rhodamine 6G ion associate with citrate (without affecting ion associates of Cd and Hg) and subsequently from Cd-I{sup -}-Rhodamine 6G ion associate with EDTA (without affecting Hg-I{sup -}-Rhodamine 6G). Multi-measurand detection and quantification by colorimetry is possible as the individual toxins gives identical bathochromic shifts in aqueous solution, i.e. from 530 to 575 nm on formation of ternary ion associates in singular, binary and ternary mixtures. The visual detection provides a simple, quick and sensitive detection method in addition to quantification via spectrophotometry with Sandell sensitivities of 1.1, 15 and 2.5 {mu}g dm{sup -2} for cadmium, lead and mercury, respectively. The developed procedure has been successfully tested for the analysis of environmental (cast alkali, lead acid battery and zinc manufacturing industry effluents) samples. Furthermore, the multi-measurand quantification of the above-mentioned heavy metal toxins based on fluorescence quenching and use of Pyronine G as chromo-ionophore instead of Rhodamine 6G is also described.

Antihistaminic and antieicosanoid effects of oleanolic and ursolic acid fraction from Helichrysum picardii.

Science.gov (United States)

Santos Rosa, C; García Gimenez, M D; Saenz Rodriguez, M T; De la Puerta Vazquez, R

2007-06-01

Helichrysum picardii Boiss. & Reuter is a Mediterranean vegetal species from the Asteraceae family. From the methanolic extract of the aerial flowering parts of this plant, a fraction of two pentacyclic triterpenes has been isolated. Gas chromatography revealed that the triterpene isomers ursolic and oleanolic acids comprised 69% and 29% respectively of the composition of this fraction. The triterpene isomeric fraction was tested in two phagocyte cell systems. It inhibited compound 48/80-induced histamine release from rat peritoneal mast cells in an approximately percentage of 45% at 100 microM and myeloperoxidase secretion from A23187-ionophore-stimulated rat peritoneal leukocytes in a significant manner at doses of 50 and 100 miroM. Furthermore, the triterpene isomers very significantly and dose-dependently inhibited generation of the cyclo-oxygenase metabolite prostaglandin E2 (41% inhibition at 50 miroM) and the 5-lipoxygenase metabolite leukotriene B4 (79% inhibition at 50 microM) from activated rat leukocytes. This anti-eicosanoid activity of the triterpene fraction was more potent than that produced by the pure triterpene oleanolic acid used for comparision, indicating a stronger action of the ursolic acid, the major compound of the isolated triterpene fraction. From these data, it can be suggested that the triterpene isomers oleanolic and ursolic acids present in the medicinal plant Helichrysum picardii contribute to the anti-inflammatory profile of this vegetal species.

Effect of forskolin and prostaglandin E1 on stimulus secretion coupling in cultured bovine adrenal chromaffin cells.

Science.gov (United States)

Marriott, D; Adams, M; Boarder, M R

1988-02-01

Treatment of adrenal chromaffin cells with forskolin (0.1-10 microM) stimulated cyclic AMP levels, reduced the maximal stimulation of release of noradrenaline by nicotine, and increased release in response to elevated external potassium and the calcium ionophore A23187. The presence of the phosphodiesterase inhibitor Ro 20-17-24 with forskolin potentiated both the stimulation of cyclic AMP and the inhibition of nicotine-induced noradrenaline release. Dibutyryl cyclic AMP, and the elevation of cyclic AMP with prostaglandin E1, also attenuated nicotine-stimulated release. However, when the stimulation of intracellular cyclic AMP production by prostaglandin E1 was potentiated by low levels of forskolin, there was not a concomitant potentiation of effect on noradrenaline release. Dideoxyforskolin, an analogue of forskolin which does not stimulate adenylate cyclase, inhibited both potassium- and nicotine-stimulated release, probably by a mechanism unrelated to the action of forskolin in these experiments. Using Fura-2 to estimate free intracellular calcium levels, both forskolin and dideoxyforskolin (at 10 microM) reduced the calcium transient in response to nicotine. These results support a model in which elevation of cyclic AMP inhibits the activation of nicotinic receptors, but augments stimulus secretion coupling downstream of calcium entry. The data, however, do not indicate a simple relationship between total intracellular cyclic AMP levels and the attenuation of nicotinic stimulation of release.

Down-regulation of GRP78 is associated with the sensitivity of chemotherapy to VP-16 in small cell lung cancer NCI-H446 cells

International Nuclear Information System (INIS)

Wang, Yingyan; Wang, Wei; Wang, Siyan; Wang, Jiarui; Shao, Shujuan; Wang, Qi

2008-01-01

Chemotherapy resistance remains a major obstacle for the treatment of small cell lung cancer (SCLC). Glucose-regulated protein 78 (GRP78), an endoplasmic reticulum chaperone, plays a critical role in chemotherapy resistance in some cancers. However, whether the suppression of the chaperone can enhance the sensitivity of chemotherapy in SCLC is still unclear. The SCLC NCI-H446 cells were divided into three groups: BAPTA-AM→A23187-treated group, A23187-treated group and control-group. Immunofluorescence, western blot and RT-PCR were used to assess the expression of GRP78 at both protein and mRNA levels. Cell apoptosis and the cell cycle distributions of the cells were analyzed by flow cytometry in order to evaluate the therapeutic sensitivity to VP-16. The expression of GRP78 at both protein and mRNA levels in the BAPTA-AM→A23187-treated cells dramatically decreased as compared to that in both A23187-treated and control groups. After treatment by VP-16, the percentage of apoptotic cells in BAPTA-AM→A23187-treated cells were: 33.4 ± 1.01%, 48.2 ± 1.77%, 53.0 ± 1.43%, 56.5 ± 2.13%, respectively, corresponding to the concentrations of BAPTA-AM 10, 15, 25, 40 μM, which was statistically significant high in comparison with the A23187-treated group and untreated-group (7.18 ± 1.03% and 27.8 ± 1.45%, respectively, p < 0.05). The results from analysis of cell cycle distribution showed that there was a significantly decreased in G 1 phase and a dramatically increased in S phase for the BAPTA-AM→A23187-treated cells as compared with the untreated cells. BAPTA-AM is a strong inhibitor of GRP78 in the NCI-H446 cell line, the down-regulation of GRP78 can significantly increase the sensitivity to VP-16. The suppression of GRP78 may offer a new surrogated therapeutic approach to the clinical management of lung cancer

Steroid modulation of the chloride ionophore in rat brain: structure-activity requirements, regional dependence and mechanism of action

Energy Technology Data Exchange (ETDEWEB)

Gee, K.W.; Bolger, M.B.; Brinton, R.E.; Coirini, H.; McEwen, B.S.

1988-08-01

Further in vitro studies of steroids active at the gamma-aminobutyric acidA (GABAA) receptor regulated Cl- channel labeled by (35S)-t-butylbicyclophosphorothionate ((35S)TBPS) reveal additional structural requirements necessary for activity. Evaluation of selected steroids for activity against TBPS-induced convulsions show similar requirements for activity. Interestingly, steroids (e.g., 5 alpha-pregnan-3 alpha, 20 alpha-diol) were identified that have high potency but limited efficacy as modulators of (35S)TBPS binding. These characteristics are reminiscent of the clinically useful benzodiazepines (BZs) such as clonazepam. However, interactions between the prototypical anesthetic-barbiturate, sodium pentobarbital, and steroids active at the Cl- channel suggest that they do not share a common site of action as allosteric modulators of (35S)TBPS and BZ receptor binding. The most potent steroid evaluated, 5 alpha-pregnan-3 alpha-ol-20-one, modulates (35S)TBPS binding at low concentrations (IC50 approximately 17 nM) in a regionally dependent manner. All (35S)TBPS binding sites appear to be functionally coupled to a steroid modulatory site. Because several of the active steroids are metabolites of progesterone, their ability to inhibit the binding of (3H)promegestrone to the cytosolic progestin receptor in rat uterus was evaluated. Those steroids showing potent activity at the GABAA receptor-Cl- ionophore were inactive at the intracellular progestin receptor. Such specificity coupled with their high potency provide additional support for the hypothesis that some of these steroids may be involved in the homeostatic regulation of brain excitability via the GABAA-BZ receptor complex.

Implication of NADPH Oxidases in the Early Inflammation Process Generated by Cystic Fibrosis Cells

Science.gov (United States)

Pongnimitprasert, Nushjira; Hurtado, Margarita; Lamari, Foudil; El Benna, Jamel; Dupuy, Corinne; Fay, Michèle; Foglietti, Marie-José; Bernard, Maguy; Gougerot-Pocidalo, Marie-Anne; Braut-Boucher, Françoise

2012-01-01

In cystic fibrosis (CF) patients, pulmonary inflammation is a major cause of morbidity and mortality. The aim of this study was to further investigate whether oxidative stress could be involved in the early inflammatory process associated with CF pathogenesis. We used a model of CFTR defective epithelial cell line (IB3-1) and its reconstituted CFTR control (S9) cell line cultured in various ionic conditions. This study showed that IB3-1 and S9 cells expressed the NADPH oxidases (NOXs) DUOX1/2 and NOX2 at the same level. Nevertheless, several parameters participating in oxidative stress (increased ROS production and apoptosis, decreased total thiol content) were observed in IB3-1 cells cultured in hypertonic environment as compared to S9 cells and were inhibited by diphenyleneiodonium (DPI), a well-known inhibitor of NOXs; besides, increased production of the proinflammatory cytokines IL-6 and IL-8 by IB3-1 cells was also inhibited by DPI as compared to S9 cells. Furthermore, calcium ionophore (A23187), which upregulates DUOX and NOX2 activities, strongly induced oxidative stress and IL-8 and IL-6 overexpression in IB3-1 cells. All these events were suppressed by DPI, supporting the involvement of NOXs in the oxidative stress, which can upregulate proinflammatory cytokine production by the airway CFTR-deficient cells and trigger early pulmonary inflammation in CF patients. PMID:24049649

Diospyros lotus leaf and grapefruit stem extract synergistically ameliorate atopic dermatitis-like skin lesion in mice by suppressing infiltration of mast cells in skin lesions.

Science.gov (United States)

Cho, Byoung Ok; Che, Denis Nchang; Yin, Hong Hua; Shin, Jae Young; Jang, Seon Il

2017-05-01

Atopic dermatitis, a chronic relapsing and pruritic inflammation of the skin also thought to be involved in, or caused by immune system destruction is an upsetting health problem due to its continuously increasing incidence especially in developed countries. Mast cell infiltration in atopic dermatitis skin lesions and its IgE-mediated activation releases various cytokines and chemokines that have been implicated in the pathogenesis of atopic dermatitis. This study was aimed at investigating synergistic anti-inflammatory, anti-pruritic and anti-atopic dermatitis effects of Diospyros lotus leaf extract (DLE) and Muscat bailey A grapefruit stem extract (GFSE) in atopic dermatitis-like induced skin lesions in mice. Combinations of DLE and GFSE inhibited TNF-α and IL-6 production more than DLE or GFSE in PMA plus calcium ionophore A23187-activated HMC-1 cells. DLE and GFSE synergistically inhibited compound 48/80-induced dermal infiltration of mast cells and reduced scratching behavior than DLE or GFSE. Furthermore, DLE and GFSE synergistically showed a stronger ameliorative effect in skin lesions by reducing clinical scores; dermal infiltration of mast cells; ear and dorsal skin thickness; serum IgE and IL-4 production in atopic dermatitis-like mice. Collectively, these results suggest that DLE and GFSE synergistically exhibit anti-atopic dermatitis effects in atopic dermatitis-like skin lesions in mice. Copyright © 2017. Published by Elsevier Masson SAS.

Effects of an angelica extract on human erythrocyte aggregation, deformation and osmotic fragility.

Science.gov (United States)

Wang, X; Wei, L; Ouyang, J P; Muller, S; Gentils, M; Cauchois, G; Stoltz, J F

2001-01-01

In Chinese traditional medicine, angelica is widely used for its known clinical effects of ameliorating blood microcirculation. But the mechanism of these beneficial effects still remains unclear. In this work the rheological behaviour of human erythrocytes treated by angelica was studied in vitro. Normal RBCs incubated with an angelica extract at different concentrations (5, 10 or 20 mg/ml) for 60 min at 37 degrees C and then their aggregation, deformation and osmotic fragility were measured with different recently developed optical techniques, namely Erythroaggregometer (Regulest, Florange, France), LORCA (Mechatronics, Amsterdam) and Fragilimeter (Regulest, Florange, France). Experimental results show that angelica (20 mg/ml) significantly decreased normal RBCs' aggregation speed (p<0.01) and could inhibit the hyperaggregability caused by dextran 500. However, the strength of normal RBCs aggregates were not influenced by angelica. When a calcium ionophore A23187 (1.9 microM) was used to harden cell membrane, angelica (20 mg/ml) could significantly (p<0.01) protect erythrocytes against the loss of their deformability even it had no effects on normal RBCs deformation. Finally angelica (5 and 10 mg/ml) decreased significantly (p<0.01) normal RBCs osmotic fragility. In conclusion angelica plays a rheologically active role on human erythrocytes, and this study suggests a possible mechanism for angelica's positive effects against certain cardiovascular diseases.

Pulmonary surfactant and its components inhibit secretion of phosphatidylcholine from cultured rat alveolar type II cells

International Nuclear Information System (INIS)

Dobbs, L.G.; Wright, J.R.; Hawgood, S.; Gonzalez, R.; Venstrom, K.; Nellenbogen, J.

1987-01-01

Pulmonary surfactant is synthesized and secreted by alveolar type II cells. Radioactive phosphatidylcholine has been used as a marker for surfactant secretion. The authors report findings that suggest that surfactant inhibits secretion of 3 H-labeled phosphatidylcholine by cultured rat type II cells. The lipid components and the surfactant protein group of M/sub r/ 26,000-36,000 (SP 26-36) inhibit secretion to different extents. Surfactant lipids do not completely inhibit release; in concentrations of 100 μg/ml, lipids inhibit stimulated secretion by 40%. SP 26-36 inhibits release with an EC 50 of 0.1 μg/ml. At concentrations of 1.0 μg/ml, SP 26-36 inhibits basal secretion and reduces to basal levels secretion stimulated by terbutaline, phorbol 12-myristate 13-acetate, and the ionophore A23187. The inhibitory effect of SP 26-36 can be blocked by washing type II cells after adding SP 26-36, by heating the proteins to 100 0 C for 10 min, by adding antiserum specific to SP 26-36, or by incubating cells in the presence of 0.2 mM EGTA. SP 26-36 isolated from canine and human sources also inhibits phosphatidylcholine release from rat type II cells. Neither type I collagen nor serum apolipoprotein A-1 inhibits secretion. These findings are compatible with the hypothesis that surfactant secretion is under feedback regulatory control

In vivo and in vitro anti-inflammatory activity of Mangifera indica L. extract (VIMANG).

Science.gov (United States)

Garrido, Gabino; González, Deyarina; Lemus, Yeny; García, Dagmar; Lodeiro, Lizt; Quintero, Gypsy; Delporte, Carla; Núñez-Sellés, Alberto J; Delgado, René

2004-08-01

A standard aqueous extract of Mangifera indica L., used in Cuba as an antioxidant under the brand name of VIMANG, was tested in vivo for its anti-inflammatory activity using commonly accepted assays. M. indica extract, administered topically (0.5-2 mg per ear), reduced ear edema induced by arachidonic acid (AA) and phorbol myristate acetate (PMA, ED50 = 1.1 mg per ear) in mice. In the PMA model, M. indica extract also reduced myeloperoxidase (MPO) activity. This extract p.o. administered also inhibited tumor necrosis factor alpha (TNFalpha) serum levels in both models of inflammation (AA, ED50 = 106.1 mg kg(-1) and PMA, ED50 = 58.2 mg kg(-1)). In vitro studies were performed using the macrophage cell line RAW264.7 stimulated with pro-inflammatory stimuli (LPS-IFNgamma or the calcium ionophore A23187) to determine PGE2 or LTB4 release, respectively. The extract inhibited the induction of PGE2 with IC50 = 64.1 microg ml(-1) and LTB4 IC50 = 22.9 microg ml(-1). M. indica extract also inhibited human synovial secretory phospholipase (PL)A2 with IC 50 = 0.7 microg ml(-1). These results represent an important contribution to the elucidation of the mechanism involved in the anti-inflammatory and anti-nociceptive effects reported by the standard M. indica extract VIMANG. Copyright 2004 Elsevier Ltd.

The potential protective role of taurine against experimental allergic inflammation.

Science.gov (United States)

Nam, Sun-Young; Kim, Hyung-Min; Jeong, Hyun-Ja

2017-09-01

Taurine has been widely evaluated as a potential therapeutic agent in chronic inflammatory disorders and various infections. However, the potential role of taurine in regulating allergic inflammatory responses is currently unknown. The present study was designed to evaluate the in vitro effects of taurine on the levels of thymic stromal lymphopoietin (TSLP) and other pro-inflammatory cytokines and activation of caspase-1 and nuclear factor (NF)-κB as well as the phosphorylations of c-Jun N-terminal kinase (JNK) and p38 in phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-triggered human mast cell line, HMC-1 cells. Furthermore, we assessed the therapeutic effects of taurine on ovalbumin (OVA)-induced allergic rhinitis (AR) animal models. Here, the obtained results showed that taurine dose-dependently inhibited the production and mRNA expression of TSLP and pro-inflammatory cytokines in HMC-1 cells exposed to PMACI. Taurine attenuated the phosphorylation of JNK and p38 in activated HMC-1 cells. Moreover, taurine brought a significant inhibition of the activities of NF-κB and caspase-1. In an OVA-induced AR animal model, the increased levels of nose rubbing, histamine, immunoglobulin E, TSLP, and interleukin IL-1β were dramatically reduced by the administration of taurine. In summary, taurine could serve as potential novel remedy of allergic inflammatory disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

The Ameliorative Effect of Sophoricoside on Mast Cell-Mediated Allergic Inflammation in Vivo and in Vitro

Directory of Open Access Journals (Sweden)

Jae-Young Um

2013-05-01

Full Text Available Sophoricoside exhibits numerous pharmacological effects, including anti- inflammatory and anti-cancer actions, yet the exact mechanism that accounts for the anti-allergic effects of sophoricoside is not completely understood. The aim of the present study was to elucidate whether and how sophoricoside modulates the mast cell-mediated allergic inflammation in vitro and in vivo. We investigated the pharmacological effects of sophoricoside on both compound 48/80 or histamine-induced scratching behaviors and 2,4-dinitrochlorobenzene (DNCB-induced atopic dermatitis in mice. Additionally, to find a possible explanation for the anti-inflammatory effects of sophoricoside, we evaluated the effects of sophoricoside on the production of histamine and inflammatory cytokines and activation of nuclear factor-κB (NF-κB and caspase-1 in phorbol 12-myristate 13-acetate plus calcium ionophore A23187 (PMACI-stimulated human mast cells (HMC-1. The finding of this study demonstrated that sophoricoside reduced compound 48/80 or histamine-induced scratching behaviors and DNCB-induced atopic dermatitis in mice. Additionally, sophoricoside inhibited the production of inflammatory cytokines as well as the activation of NF-κB and caspase-1 in stimulated HMC-1. Collectively, the findings of this study provide us with novel insights into the pharmacological actions of sophoricoside as a potential molecule for use in the treatment of allergic inflammation diseases.

Fisetin inhibits IL-31 production in stimulated human mast cells: Possibilities of fisetin being exploited to treat histamine-independent pruritus.

Science.gov (United States)

Che, Denis Nchang; Cho, Byoung Ok; Shin, Jae Young; Kang, Hyun Ju; Kim, Young-Soo; Jang, Seon Il

2018-05-15

Interleukin-31 (IL-31) is a recently discovered cytokine that is tightly linked to the pathogenesis of pruritus seen in atopic dermatitis. Flavonoids, like fisetin, are naturally occurring molecules with antioxidant, cytoprotective, and anti-inflammatory actions. the present study sought to investigate whether fisetin modulates IL-31 and histamine release in human mast cells (HMC-1). HMC-1 cells were pretreated with fisetin at various doses and stimulated with phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PI) for different time intervals. We evaluated IL-31 production and histamine release and signaling mechanism of the action of fisetin on IL-31 production. We also investigated the effects of fisetin on scratching behaviors in mice. Fisetin decreased PI-stimulated mRNA expression and production of IL-31 in HMC-1 cells. Fisetin inhibited PI-induced phosphorylation of mitogen-activated protein kinases that further suppressed nuclear factor (NF-κB) activation and translocation to the nucleus through the inhibition of IκB-α phosphorylation. Fisetin also prevented mast cell release of histamine in HMC-1 cells. Mice in-vivo studies show that fisetin reduced scratching behaviors in mice. These pharmacological actions of fisetin provide new suggestions that fisetin can be of potential use for the treatment of pruritus that cannot be treated with histamine receptor blockers alone. Copyright © 2018 Elsevier Inc. All rights reserved.

Application of pyridine-2-carbaldehyde-2-(4-methyl-1,3-benzo thiazol-2-yl)hydrazone as a neutral ionophore in the construction of a novel Er(III) sensor

Energy Technology Data Exchange (ETDEWEB)

Ganjali, Mohammad Reza; Norouzi, Parviz [University of Tehran, Tehran (Iran, Islamic Republic of). Center of Excellence in Electrochemistry; Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; E-mail: ganjali@khayam.ut.ac.ir; Rezapour, Morteza; Rasoolipour, Solmaz [University of Tehran, Tehran (Iran, Islamic Republic of). Center of Excellence in Electrochemistry; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). University College of Science. Faculty of Chemistry

2007-03-15

We found that pyridine-2-carbaldehyde-2-(4-methyl-1,3-benzothiazol-2-yl) hydrazone (PCMHT) can be used as a suitable neutral ionophore for preparing an Er(III) membrane sensor with high selectivity. The optimum composition was found to be PCMHT-PVC-KTpClPB-BA with the ratios of 6.0:30.0:5.0:59.0, respectively. The Nernstian response was of 21.8 {+-} 0.5 mV decade{sup -1} of Er(III) activity, the linear range of the sensor was found to be relatively wide (from 1.0X10{sup -5} to 1.0 X10{sup -2} mol L{sup -1}). Its applicability pH range of 2.5-12.0 seems to make it suitable for analytical applications. The lower detection limit (LDL) of the sensor was 5.0 X10{sup -6} mol L{sup -1}. The excellent Er(III)-selectivity of the proposed sensor with regard to most common metal ions, and especially, lanthanide ions is another advantage. It was successfully used as an indicator electrode for titration of 25 mL of a 1.0 X 10{sup -4} mol L{sup -1} Er(III) ions with a 1.0 X 10{sup -}2 mol L{sup -1} EDTA. The proposed sensor was used for direct monitoring of Er(III) in binary mixtures and indirect determination of fluoride ions in two mouth wash preparations. (author)

Inhibition of neurotensin-stimulated mast cell secretion and carboxypeptidase A activity by the peptide inhibitor of carboxypeptidase A and neurotensin-receptor antagonist SR 48692.

Science.gov (United States)

Miller, L A; Cochrane, D E; Feldberg, R S; Carraway, R E

1998-06-01

Neurotensin (NT), a peptide found in brain and several peripheral tissues, is a potent stimulus for mast cell secretion and its actions are blocked by the specific NT receptor antagonist, SR 48692. Subsequent to stimulation, NT is rapidly degraded by mast cell carboxypeptidase A (CPA). In the experiments described here, we tested for the involvement of CPA activity in the activation of mast cell secretion by the peptide, NT. Mast cells were isolated from the peritoneal and pleural cavities of rats, purified over metrizamide gradients and incubated at 37 degrees C in Locke solution or Locke containing the appropriate inhibitors. For some experiments, media derived from mast cells stimulated by compound 48/80 were used as a source of mast cell CPA activity. Treatment of mast cells with the highly specific peptide inhibitor of CPA derived from potato (PCI) inhibited histamine release in response to NT and NT8-13 (the biologically active region of NT). This inhibition required some 20 min to develop and was only partially reversed by a 20-min wash period. PCI (10 microM) did not inhibit histamine release in response to NT1-12, bradykinin, compound 48/80, the calcium ionophore, A23187, or anti-IgE serum. PCI also inhibited mast cell CPA activity. SR 48692, a highly selective antagonist of the brain NT receptor and of NT-stimulated mast cell secretion, also inhibited mast cell CPA activity as well as bovine pancreatic CPA activity in a concentration-dependent manner. It is suggested that the mast cell binding site for NT and the active site for CPA may share similar characteristics. The results are discussed in terms of NT mechanism of action on the mast cell.

Interleukin-1α Induction in Human Keratinocytes (HaCaT: An In Vitro Model for Chemoprevention in Skin

Directory of Open Access Journals (Sweden)

T. Magcwebeba

2012-01-01

Full Text Available Long-term exposure to UV irradiation and toxic chemicals is associated with chronic inflammation that contributes to skin cancer development with interleukin-1 alpha (IL-1α, constitutively produced by keratinocytes, playing a pivotal role in skin inflammation. The aim of this study was to investigate the modulation of IL-1α production in the HaCaT keratinocyte cell line. Phorbol 12-myristate 13-acetate failed to induce IL-1α in HaCaT cells, and this might be associated with the specific deficiency known to affect downstream signalling of the MEK/ERK pathway in these cells. The calcium ionophore, ionomycin, slightly enhanced the production of intracellular (icIL-1α, but this resulted in a necrotic release at higher concentrations. UV-B exposure significantly increased the production of icIL-1α in a dose-dependent manner with a maximal induction exhibited at 24 h with minimal necrotic and apoptotic effects. Validation of the HaCaT cell model indicated that the nonsteroidal anti-inflammatory drug (NSAID, ibuprofen, and the glucocorticoid, dexamethasone, inhibited icIL-1α production, and this was associated with a slight inhibition of cell viability. The UV-B-induced keratinocyte cell model provides an in vitro system that could, apart from phorbol ester-like compounds, be utilised as a screening assay in identifying skin irritants and/or therapeutic topical agents via the modulation of IL-1α production.

Inhibition of Release of Vasoactive and Inflammatory Mediators in Airway and Vascular Tissues and Macrophages by a Chinese Herbal Medicine Formula for Allergic Rhinitis

Directory of Open Access Journals (Sweden)

George Binh Lenon

2007-01-01

Full Text Available Herbal therapies are being used increasingly for the treatment of allergic rhinitis. The aim of this study was to investigate the possible pharmacological actions and cellular targets of a Chinese herbal formula (RCM-101, which was previously shown to be effective in reducing seasonal allergic rhinitis symptoms in a randomized, placebo-controlled clinical trial. Rat and guinea pig isolated tissues (trachea and aorta were used to study the effects of RCM-101 on responses to various mediators. Production of leukotriene B4 in porcine neutrophils and of prostaglandin E2 and nitric oxide (NO in Raw 264.7 cells were also measured. In rat and guinea pig tracheal preparations, RCM-101 inhibited contractile responses to compound 48/80 but not those to histamine (guinea pig preparations or serotonin (rat preparations. Contractile responses of guinea pig tracheal preparations to carbachol and leukotriene C4, and relaxant responses to substance P and prostaglandin E2 were not affected by RCM-101. In rat aortic preparations, precontracted with phenylephrine, endothelium-dependent relaxant responses to acetylcholine and endothelium-independent relaxant responses to sodium nitroprusside were not affected by RCM-101. However, RCM-101 inhibited relaxations to l-arginine in endothelium-denuded rat aortic preparations, which had been pre-incubated with lipopolysaccharide. RCM-101 did not affect leukotriene B4 formation in isolated porcine neutrophils, induced by the calcium ionophore A23187; however, it inhibited prostaglandin E2 and NO production in lipopolysaccharide-stimulated murine macrophages (Raw 264.7 cells.The findings indicate that RCM-101 may have multiple inhibitory actions on the release and/or synthesis of inflammatory mediators involved in allergic rhinitis.

sigma receptor ligands attenuate N-methyl-D-aspartate cytotoxicity in dopaminergic neurons of mesencephalic slice cultures.

Science.gov (United States)

Shimazu, S; Katsuki, H; Takenaka, C; Tomita, M; Kume, T; Kaneko, S; Akaike, A

2000-01-28

We investigated the potential neuroprotective effects of several sigma receptor ligands in organotypic midbrain slice cultures as an excitotoxicity model system. When challenged with 100-microM N-methyl-D-aspartate (NMDA) for 24 h, dopaminergic neurons in midbrain slice cultures degenerated, and this was prevented by (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,b]-cyclohepten-5, 10-imine (MK-801; 1-10 microM). Concomitant application of ifenprodil (1-10 microM) or haloperidol (1-10 microM), both of which are high-affinity sigma receptor ligands, significantly attenuated the neurotoxicity of 100 microM NMDA. The sigma(1) receptor-selective ligand (+)-N-allylnormetazocine ((+)-SKF 10047; 1-10 microM) was also effective in attenuating the toxicity of NMDA. The effect of R(-)-N-(3-phenyl-1-propyl)-1-phenyl-2-aminopropane hydrochloride ((-)-PPAP), a sigma receptor ligand with negligible affinity for the phencyclidine site of NMDA receptors, was also examined. (-)-PPAP (3-100 microM) caused a concentration-dependent reduction of NMDA cytotoxicity, with significant protection at concentrations of 30 and 100 microM. In contrast, (+)-SKF 10047 (10 microM) and (-)-PPAP (100 microM) showed no protective effects against cell death induced by the Ca(2+) ionophore ionomycin (1-3 microM). These results indicate that sigma receptor ligands attenuate the cytotoxic effects of NMDA on midbrain dopaminergic neurons, possibly via inhibition of NMDA receptor functions.

Assessment of the metabolic effects of the ionophore grisorixin on myocardial cells in culture with 14-C-labelled substrates

International Nuclear Information System (INIS)

Maublant, J.C.; Gachon, P.; Ross, M.R.; Davidson, W.D.; Mena, I.

1984-01-01

Cultures of myocardial cells were utilized to verify the hypothesis that the ionophore grisorixin could facilitate the anaerobic and impair the aerobic metabolism in the myocardium. This was suggested by previous experiments in which the authors found an increase in the cardiac work without increase in the oxygen consumption, while the myocardial uptake of 123-Iodo-hexadecenoic acid was decreased. Tissue cultures were prepared by trypsinization of the myocardium of two to four-day old newborn mice. The cultures were incubated with 14-C-glucose (n=10), 14-C-octanoate (n=14) or 14-C-acetate (n=12). Except for the controls (n=19), they also received 1 μg/ml of an alcoholic solution of grisorixin or 200 μl of 60% alcohol. The cultures were then placed in a circuit with a closed circulation of air which passed through a vibrating reed electrometer for detection of the beta radiations of the 14-CO/sub 2/ liberated by the 14-C labelled substrates. The activity was permanently recorded for measurements of the rate of consumption of these substrates. Compared to the control values, the metabolic rate with grisorixin was significantly decreased for octanoate (77 +- 22 vs 169 +- 62 rho mole/min/mg prot, rho<0.01) and acetate (2.7 +- 1.0 vs 6.0 +- 1.3 rho mole/min/mg prot, rho<0.01). The results for glucose were 1.05 +- 0.24 vs 0.88 +- 0.24 n mole/min/mg prot, (rho<0.10). Alcohol alone produced no significant effect except on the octanoate consumption. These results provide direct evidence that grisorixin favors the anaerobic pathway in the metabolism of the myocardial cells

A calixarene-based ion-selective electrode for thallium(I) detection.

Science.gov (United States)

Chester, Ryan; Sohail, Manzar; Ogden, Mark I; Mocerino, Mauro; Pretsch, Ernö; De Marco, Roland

2014-12-03

Three new calixarene Tl(+) ionophores have been utilized in Tl(+) ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10(-2)-10(-6)M TlNO3 with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (logβIL) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn(2+), Ca(2+), Ba(2+), Cu(2+), Cd(2+) and Al(3+) with moderate selectivity against Pb(2+), Li(+), Na(+), H(+), K(+), NH4(+) and Cs(+), noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)-poly(decyl methacrylate) (PMMA-PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4mVdecade(-1) and a lower detection limit of 30.2nM. Due to the presence of an undesirable water layer and/or leaching of redox mediator from the graphite redox buffered SC, a coated wire electrode on gold and graphite redox buffered SC yielded grossly inferior detection limits against the polypyrrole/PVC SC and POT/PMMA-PDMA SC ISEs that did not display signs of a water layer or leaching of SC ingredients into the membrane. Copyright © 2014 Elsevier B.V. All rights reserved.

Role of calcium in gonadotropin releasing hormone-induced luteinizing hormone secretion from the bovine pituitary

International Nuclear Information System (INIS)

Kile, J.P.

1986-01-01

The hypothesis was tested that GnRH acts to release LH by increasing calcium uptake by gonadotroph which in turn stimulates calcium-calmodulin activity and results in LH release from bovine pituitary cells as it does in the rat. Pituitary glands of calves (4-10 months of age) were enzymatically dispersed (0.2% collagenase) and grown for 5 days to confluency in multiwell plates (3 x 10 5 /well). Cells treated with GnRH Ca ++ ionophore A23187, and ouabain all produced significant releases of LH release in a pronounced all or none fashion, while thorough washing of the cells with 0.5 mM EGTA in Ca ++ -free media prevented the action of GnRH. GnRH caused a rapid efflux of 45 Ca ++ . Both GnRH-stimulated 45 Ca efflux and LH release could be partially blocked by verapamil GnRH-induced LH release could also be blocked by nifedipine and tetrodotoxin, although these agents did not affect 45 Ca efflux. The calmodulin antagonists calmidazolium and W7 were found to block GnRH induced LH release, as well as LH release induced by theophylline, KC PGE 2 and estradiol. These data indicated that: (1) calcium is required for GnRH action, but extracellular Ca ++ does not regulate LH release; (2) GnRH elevates intracellular Ca ++ by opening both voltage sensitive and receptor mediated Ca ++ channels; (3) activation of calmodulin is one mechanism involved in GnRH-induced LH release

Products of neutrophils and eosinophils increase the responsiveness of human isolated bronchial tissue.

Science.gov (United States)

Hallahan, A R; Armour, C L; Black, J L

1990-05-01

This study examines the possibility that products of neutrophils and eosinophils could increase the responsiveness of human isolated bronchial tissue. Neutrophils and eosinophils were isolated from the peripheral blood of healthy volunteers. The cells were incubated with 1 microM calcium ionophore A23187 for 10-15 min then centrifuged, the supernatant collected and stored at -70 degrees C. Human bronchial rings (2-3 mm diameter, 3-4 mm long) were prepared from specimens resected at thoracotomy. The tissues were suspended in organ baths under a 1 g load and changes in tension measured isometrically. Stable contractions to bolus doses of histamine (0.1-10 microM) or to electrical field stimulation (40-100 V, 4-16 Hz, 1 ms for 20 s) were established. Supernatant from 106 neutrophils or 105 eosinophils was then added and tissue responsiveness reassessed. Neutrophil supernatant increased tissue responsiveness to histamine and electrical field stimulation by 54 +/- 17% (n = 5, p less than 0.05) and 18 +/- 7% (n = 6, p less than 0.05), respectively. Eosinophil supernatant increased the histamine response by 60 +/- 23% (n = 8, p less than 0.05) while tissue responsiveness to electrical field stimulation was unchanged (n = 3). Thus, as neutrophils and eosinophils can change the responsiveness of human bronchus in vitro it is possible that they do this in vivo and may not simply be temporally related to the development of bronchial hyperresponsiveness.

Flavonoids inhibit histamine release and expression of proinflammatory cytokines in mast cells.

Science.gov (United States)

Park, Hyo-Hyun; Lee, Soyoung; Son, Hee-Young; Park, Seung-Bin; Kim, Mi-Sun; Choi, Eun-Ju; Singh, Thoudam S K; Ha, Jeoung-Hee; Lee, Maan-Gee; Kim, Jung-Eun; Hyun, Myung Chul; Kwon, Taeg Kyu; Kim, Yeo Hyang; Kim, Sang-Hyun

2008-10-01

Mast cells participate in allergy and inflammation by secreting inflammatory mediators such as histamine and proinflammatory cytokines. Flavonoids are naturally occurring molecules with antioxidant, cytoprotective, and antiinflammatory actions. However, effect of flavonoids on the release of histamine and proinflammatory mediator, and their comparative mechanism of action in mast cells were not well defined. Here, we compared the effect of six flavonoids (astragalin, fisetin, kaempferol, myricetin, quercetin, and rutin) on the mast cell-mediated allergic inflammation. Fisetin, kaempferol, myricetin, quercetin, and rutin inhibited IgE or phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-mediated histamine release in RBL-2H3 cells. These five flavonoids also inhibited elevation of intracellular calcium. Gene expressions and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-8 were assessed in PMACI-stimulated human mast cells (HMC-1). Fisetin, quercetin, and rutin decreased gene expression and production of all the proinflammatory cytokines after PMACI stimulation. Myricetin attenuated TNF-alpha and IL-6 but not IL-1beta and IL-8. Fisetin, myricetin, and rutin suppressed activation of NF-kappaB indicated by inhibition of nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. The pharmacological actions of these flavonoids suggest their potential activity for treatment of allergic inflammatory diseases through the down-regulation of mast cell activation.

Nur77 nuclear import and its NBRE-binding activity in thymic lymphoma cells are regulated by different mechanisms sensitive to FK506 or HA1004

International Nuclear Information System (INIS)

Kochel, Izabela; Rapak, Andrzej; Ziolo, Ewa; Strzadala, Leon

2005-01-01

Thymic lymphoma cells restore their sensitivity to ionomycin-induced apoptosis when treated with FK506 or HA1004. In apoptosis-resistant cells, ionomycin-induced Nur77 strongly binds DNA during the first 2 h of response, in contrast to lymphoma cells treated with ionomycin together with FK506 or HA1004, which undergo massive apoptosis. We show that Nur77 could discriminate between calcium signals sensitive to FK506 and those sensitive to HA1004, as the inhibitors differentially regulate the kinetics of Nur77 nuclear import, and FK506, unlike HA1004, inhibits Nur77 DNA-binding activity. In the presence of HA1004, NBRE binding by Nur77 protein increases with time (6 h vs 2 h), whereas the final outcome of both inhibitors is apoptosis of thymic lymphoma cells

Neomysin inhibits Ca2+-stimulated phosphatidylinositol hydrolysis and protects cultured rat cardiomyocytes from Ca2+-dependent cell injury

International Nuclear Information System (INIS)

Babson, J.R.; Dougherty, J.M.

1991-01-01

Exposure of cultured rat cardiomyocytes to ionomycin and extracellular Ca 2+ leads to a rapid, sustained increase in intracellular free Ca 2+ as monitored by Ca 2+ -dependent phosphorylase a activation and to a subsequent loss of cardiomyocyte viability as determined by lactate dehydrogenase (LDH) leakage. The intracellular free Ca 2+ increase coincided with a rapid hydrolysis of phosphatidylinositol that preceded cell death. Phosphatidylinositol hydrolysis was monitored by the release of radiolabeled phosphoinositides from cardiomyocytes prelabeled with [2- 3 H]-myo-inositol. Neomycin, a known inhibitor of phospholipase C, inhibited the phosphatidylinositol hydrolysis and markedly reduced the extent of cell injury. Inhibitors of other Ca 2+ -activated processes, including intracellular proteases and phospholipase A 2 , had no effect on ionomycin-mediated cell injury. These data suggest that ionomycin-induced Ca 2+ -dependent cell injury in cultured cardiomyocytes may be due in part to the stimulation of phosphatidylinositol hydrolysis, presumably catalyzed by a Ca 2+ -dependent phospholipase C

Ionophore-Based Potentiometric Sensors for the Flow-Injection Determination of Promethazine Hydrochloride in Pharmaceutical Formulations and Human Urine

Directory of Open Access Journals (Sweden)

Suad Mustafa Al-Araji

2011-01-01

Full Text Available Plasticised poly(vinyl chloride-based membranes containing the ionophores (α-, β- and γ-cyclodextrins (CD, dibenzo-18-crown-6 (DB18C6 and dibenzo-30-crown-10 (DB30C10 were evaluated for their potentiometric response towards promethazine (PM in a flow injection analysis (FIA set-up. Good responses were obtained when β- and γ-CDs, and DB30C10 were used. The performance characteristics were further improved when tetrakis(4-chlorophenyl borate (KTPB was added to the membrane. The sensor based on β-CD, bis(2-ethylhexyl adipate (BEHA and KTPB exhibited the best performance among the eighteen sensor compositions that were tested. The response was linear from 1 x 10−5 to 1 x 10−2 M, slope was 61.3 mV decade−1, the pH independent region ranged from 4.5 to 7.0, a limit of detection of 5.3 x 10−6 M was possible and a lifetime of more than a month was observed when used in the FIA system. Other plasticisers such as dioctyl phenylphosphonate and tributyl phosphate do not show significant improvements in the quality of the sensors. The promising sensors were further tested for the effects of foreign ions (Li+, Na+, K+, Mg2+, Ca2+, Co2+, Cu2+, Cr3+, Fe3+, glucose, fructose. FIA conditions (e.g., effects of flow rate, injection volume, pH of the carrier stream were also studied when the best sensor was used (based on β-CD. The sensor was applied to the determination of PM in four pharmaceutical preparations and human urine that were spiked with different levels of PM. Good agreement between the sensor and the manufacturer’s claimed values (for pharmaceutical preparations was obtained, while mean recoveries of 98.6% were obtained for spiked urine samples. The molecular recognition features of the sensors as revealed by molecular modelling were rationalised by the nature of the interactions and complexation energies between the host and guest molecules.

In Vivo Histamine Optical Nanosensors

Directory of Open Access Journals (Sweden)

Heather A. Clark

2012-08-01

Full Text Available In this communication we discuss the development of ionophore based nanosensors for the detection and monitoring of histamine levels in vivo. This approach is based on the use of an amine-reactive, broad spectrum ionophore which is capable of recognizing and binding to histamine. We pair this ionophore with our already established nanosensor platform, and demonstrate in vitro and in vivo monitoring of histamine levels. This approach enables capturing rapid kinetics of histamine after injection, which are more difficult to measure with standard approaches such as blood sampling, especially on small research models. The coupling together of in vivo nanosensors with ionophores such as nonactin provide a way to generate nanosensors for novel targets without the difficult process of designing and synthesizing novel ionophores.

Regulation of IFN regulatory factor 4 expression in human T cell leukemia virus-I-transformed T cells.

Science.gov (United States)

Sharma, Sonia; Grandvaux, Nathalie; Mamane, Yael; Genin, Pierre; Azimi, Nazli; Waldmann, Thomas; Hiscott, John

2002-09-15

IFN regulatory factor (IRF)-4 is a lymphoid/myeloid-restricted member of the IRF transcription factor family that plays an essential role in the homeostasis and function of mature lymphocytes. IRF-4 expression is tightly regulated in resting primary T cells and is transiently induced at the mRNA and protein levels after activation by Ag-mimetic stimuli such as TCR cross-linking or treatment with phorbol ester and calcium ionophore (PMA/ionomycin). However, IRF-4 is constitutively upregulated in human T cell leukemia virus type I (HTLV-I) infected T cells as a direct gene target for the HTLV-I Tax oncoprotein. In this study we demonstrate that chronic IRF-4 expression in HTLV-I-infected T lymphocytes is associated with a leukemic phenotype, and we examine the mechanisms by which continuous production of IRF-4 is achieved in HTLV-I-transformed T cells. IRF-4 expression in HTLV-1-infected cells is driven through activation of the NF-kappaB and NF-AT pathways, resulting in the binding of p50, p65, and c-Rel to the kappaB1 element and p50, c-Rel, and NF-ATp to the CD28RE element within the -617 to -209 region of the IRF-4 promoter. Furthermore, mutation of either the kappaB1 or CD28RE sites blocks Tax-mediated transactivation of the human IRF-4 promoter in T cells. These experiments constitute the first detailed analysis of human IRF-4 transcriptional regulation within the context of HTLV-I infection and transformation of CD4(+) T lymphocytes.

In vivo and in vitro HeNe laser effects on phagocyte functions

Energy Technology Data Exchange (ETDEWEB)

Ricevuti, G.; Mazzone, A.; Monaia, C.; Fratino, P.; Degiulio, R.; Dell' Acqua, R.; Leonardi, G.; Jucci, A.; Sacchi, S. (Univ. of Pavia (Italy))

1989-10-01

The goal of this work was to evaluate the effect of helium-neon (HeNe) laser irradiation on immunocompetent cells. We used the in vivo skin window method and in vitro granulocyte function tests. The study of cellular migration showed a marked decrease in vitro and in vivo in a dose-independent manner. Superoxide release was not modified by laser irradiation. The granulocyte's aggregation, when using PHA and PMA, presented a reduction that was statistically very significant, not as a subordinate dose. An increase of the release of ATP was demonstrated only at 4 joules and precedes granulocyte aggregation. When using Ca2+ ionophore A23187 as stimulus, laser irradiation at 1, 2 or 4J did not show any modification of granulocyte aggregation. The monoclonal antibody 60.1, which identifies a membrane antigen fundamental for aggregation and chemotaxis, is expressed in normal amounts on granulocyte membranes both before and after irradiation with a HeNe laser. In fact, laser irradiation preferentially attacks the area of the cellular centrosome that determines a modification of cellular morphology. The electron microscope and immunofluorescence study with a monoclonal antibody have pointed out a disorganization of the microtubules. The alteration of some of the granulocyte functions is correlated to the damage in the centrioles. The granulocyte mitochondrial system and surface membrane remain intact, and this explains the normal production and release of free radicals. Further experiments are necessary to evaluate the clinical application of lasers in various diseases with immunophagocytic pathogenesis.

Repeated allergen exposure reduce early phase airway response and leukotriene release despite upregulation of 5-lipoxygenase pathways

Directory of Open Access Journals (Sweden)

Cui Zhi-Hua

2012-03-01

Full Text Available Abstract Background Allergen induced early phase airway response and airway plasma exudation are predominantly mediated by inflammatory mast cell mediators including histamine, cysteinyl leukotrienes (cysLTs and thromboxane A2 (TXA2. The aim of the present study was to evaluate whether repeated allergen exposure affects early phase airway response to allergen challenge. Methods A trimellitic anhydride (TMA sensitized guinea pig model was used to investigate the effects of low dose repeated allergen exposure on cholinergic airway responsiveness, early phase airway response and plasma exudation, as well as local airway production of mast cell derived cysteinyl leukotrienes and thromboxane B2 (TXB2 after allergen challenge. Results Repeated low dose allergen exposure increased cholinergic airway responsiveness. In contrast, early phase airway response and plasma exudation in response to a high-dose allergen challenge were strongly attenuated after repeated low dose allergen exposure. Inhibition of the airway response was unspecific to exposed allergen and independent of histamine receptor blocking. Furthermore, a significant reduction of cysteinyl leukotrienes and TXB2 was found in the airways of animals repeatedly exposed to a low dose allergen. However, in vitro stimulation of airway tissue from animals repeatedly exposed to a low dose allergen with arachidonic acid and calcium ionophore (A23187 induced production of cysteinyl leukotrienes and TXB2, suggesting enhanced activity of 5-lipoxygenase and cyclooxygenase pathways. Conclusions The inhibition of the early phase airway response, cysteinyl leukotriene and TXB2 production after repeated allergen exposure may result from unresponsive effector cells.

The Uremic Toxin Acrolein Promotes Suicidal Erythrocyte Death

Directory of Open Access Journals (Sweden)

Mohamed Siyabeldin E. Ahmed

2013-05-01

Full Text Available Background: Anemia is a major complication of end stage renal disease. The anemia is mainly the result of impaired formation of erythrocytes due to lack of erythropoietin and iron deficiency. Compelling evidence, however, points to the contribution of accelerated erythrocyte death, which decreases the life span of circulating erythrocytes. Erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine-exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i. Erythrocytes could be sensitized to cytosolic Ca2+ by ceramide. In end stage renal disease, eryptosis may possibly be stimulated by uremic toxins. The present study explored, whether the uremic toxin acrolein could trigger eryptosis. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin-V-binding, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, and ceramide from fluorescent antibodies. Results: A 48 h exposure to acrolein (30 － 50 µM did not significantly modify [Ca2+]i but significantly decreased forward scatter and increased annexin-V-binding. Acrolein further triggered slight, but significant hemolysis and increased ceramide formation in erythrocytes. Acrolein (50 µM induced annexin-V-binding was significantly blunted in the nominal absence of extracellular Ca2+. Acrolein augmented the annexin-V-binding following treatment with Ca2+ ionophore ionomycin (1 µM. Conclusion: Acrolein stimulates suicidal erythrocyte death or eryptosis, an effect at least in part due to stimulation of ceramide formation with subsequent sensitisation of the erythrocytes to cytosolic Ca2+.

Comparison of the effects of stimulators and inhibitors of resorption on the release of lysosomal enzymes and radioactive calcium from fetal bone in organ culture

International Nuclear Information System (INIS)

Eilon, G.; Raisz, L.G.

1978-01-01

The release of lysosomal enzymes, collagenase, and previously incorporated 45 Ca from fetal rat long bones cultured in a chemically defined medium is compared. Parathyroid hormone (PTH) and prostaglandin E 2 increased the release of β-glucuronidase, acetylglucosaminidase, and cathepsin D, but showed little effect on collagenase activity in the medium at 48 h. The dose-response relations for β-glucuronidase and 45 Ca release were similar. However, the increase in lysosomal enzyme release was proportionally greater and occurred earlier than the increase in 45 Ca release. PTH also caused a significant increase in total β-glucuronidase activity in bone plus medium. Several agents which stimulate 45 Ca release at an optimal concentration, but not at a higher concentration, including dibutyryl cAMP, isobutylmethylxanthine, and the calcium ionophore, A23187, all increased lysosomal enzyme release at the concentration which increased 45 Ca release. Three inhibitors of bone resorption (calcitonin, cortisol, and colchicine) blocked lysosomal enzyme release at the same time that 45 Ca release decreased. When the bones escaped from calcitonin inhibition, both 45 Ca and lysosomalenzyme release increased. While colchicine blocked both lysosomal enzymes and 45 CA release, it actually increased the release of bone collagenase, and together with PTH or prostaglandin E 2 caused a large increase in free collagenase activity in the medium. These data indicate that lysosomal enzyme release is closely linked to bone resorption and suggest that lysosomal enzymes may have a primary role in initiating resorption, perhaps by acting on noncollagenous matrix or tissue components before mineral removal and collagen degradation

Ocorrência de resíduos de ionóforos poliéteres em leite UHT comercializado na região metropolitana do Rio de Janeiro | Occurrence of polyether ionophore residues in UHT milk marketed in the metropolitan region of Rio de Janeiro

Directory of Open Access Journals (Sweden)

Mararlene Ulberg Pereira

2015-08-01

Full Text Available Os ionóforos poliéteres são antibióticos utilizados em bovinos como promotores de crescimento, para aumentar a produção de leite em vacas em lactação e prevenir e tratar a coccidiose. Os ionóforos poliéteres autorizados como aditivos antimicrobianos no Brasil para uso na alimentação de bovinos e vacas leiteiras são a lasalocida e a monensina sódica. Entretanto, poucos são os métodos analíticos para determinação destes resíduos em leite e não há dados de monitoramento disponíveis no Brasil. Essa classe ainda não está incluída nos programas de controle de resíduos em leite implementados pela Agência Nacional de Vigilância Sanitária e pelo Ministério da Agricultura, Pecuária e Abastecimento. Este trabalho teve como objetivo avaliar a ocorrência de seis ionóforos poliéteres em leite UHT empregando um método analítico desenvolvido e validado no Instituto Nacional de Controle de Qualidade em Saúde. O método foi aplicado em 102 amostras de leite integral UHT comercializadas na região metropolitana do Rio de Janeiro. Nas amostras analisadas somente resíduos do antibiótico monensina foram encontrados. Esta substância foi detectada em 14% das amostras, mas as concentrações estimadas foram bem inferiores ao limite máximo de resíduo de 2 µg/kg recomendado pelo Codex Alimentarius e pela Comunidade Europeia. ----------------------------------------------------------------------------------------------- Polyether ionophore antibiotics are used in cattle to promote growth, to increase milk production in lactating cows, and to prevent and treat coccidiosis. In Brazil, lasalocid and monensin are the two polyether ionophores that are allowed as antimicrobial additives in cattle and dairy cow feed. However, there are few methods for determining the residues of these additives in milk, and no monitoring data are available in Brazil. These residues are not yet included in the residue control programs in the milk matrix

Calcium uptake and release by isolated cortices and microsomes from the unfertilized egg of the sea urchin strongylocentrotus droebachiensis

International Nuclear Information System (INIS)

Oberdorf, J.A.

1986-01-01

Two subcellular fractions of the sea urchin egg were studied for their potential role in regulating the transient rise in cytosolic calcium that accompanies fertilization. Isolated cortices from unfertilized sea urchin eggs sequester calcium in an ATP dependent manner when incubated in a medium containing free calcium levels characteristic of the resting cell. This ATP dependent calcium uptake activity, measured in the presence of 5mM Na Azide to prevent mitochondrial accumulation, was increased by oxalate, and was blocked by 150 μM quercetin and 50 μM vanadate. Cortices preloaded with 45 Ca in the presence of ATP dramatically increased their rate of calcium efflux upon the addition of (1) the calcium ionophore A23187 (10 μM), (2) trifluoperazine (200 μM), (3) concentrations of free calcium that activated cortical granule exocytosis, and (4) the calcium mobilizing agent inositol trisphosphate (IP3). This pool of calcium is most likely sequestered in the portion of the egg's endoplasmic reticulum (ER) that remains associated with the cortical region during its isolation. They have developed a method for obtaining a high yield of purified microsomal vesicles from whole eggs. This preparation also demonstrates ATP dependent calcium sequestering activity which increases in the presence of oxalate and has similar sensitivities to calcium transport inhibitors, however the isolated microsomal vesicles did not show any detectable release of calcium when exposed to IP3. Procedures originally developed for purifying calsequestrin were used to partially purify a 58,000 MW protein from the egg's microsomal vesicles

Inhibitory effects of bee venom on mast cell-mediated allergic inflammatory responses.

Science.gov (United States)

Kang, Yun-Mi; Chung, Kyung-Sook; Kook, In-Hoon; Kook, Yoon-Bum; Bae, Hyunsu; Lee, Minho; An, Hyo-Jin

2018-06-01

Although bee venom (BV) is a toxin that causes bee stings to be painful, it has been widely used clinically for the treatment of certain immune‑associated diseases. BV has been used traditionally for the treatment of chronic inflammatory diseases. In this regard, the present study analyzed the effect of BV on the regulation of inflammatory mediator production by mast cells and their allergic inflammatory responses in an animal model. HMC‑1 cells were treated with BV prior to stimulation with phorbol‑12‑myristate 13‑acetate plus calcium ionophore A23187 (PMACI). The production of allergy‑associated pro‑inflammatory mediators was examined, and the underlying mechanisms were investigated. Furthermore, to investigate whether BV exhibits anti‑inflammatory effects associated with anti‑allergic effects in vivo, a compound 48/80‑induced anaphylaxis model was used. BV inhibited histamine release, mRNA expression and production of cytokines in the PMACI‑stimulated HMC‑1 cells. Furthermore, the inhibitory effects of BV on mitogen‑activated protein kinase (MAPK), MAPK kinase, signal transducer and activator of transcription 3 (STAT3) and Akt were demonstrated. The present study also investigated the ability of BV to inhibit compound 48/80‑induced systemic anaphylaxis in vivo. BV protected the mice against compound 48/80‑induced anaphylactic‑associated mortality. Furthermore, BV suppressed the mRNA expression levels of pro‑inflammatory cytokines, and suppressed the activation of MAPK and STAT3 in this model. These results provide novel insights into the possible role of BV as a modulator for mast cell‑mediated allergic inflammatory disorders.

Calcium transport in sealed vesicles from red beet (Beta vulgaris L.) storage tissue. II. Characterization of 45Ca2+ uptake into plasma membrane vesicles

International Nuclear Information System (INIS)

Giannini, J.L.; Ruiz-Cristin, J.; Briskin, D.P.

1987-01-01

Calcium uptake was examined in sealed plasma membrane vesicles isolated from red beet (Beta vulgaris L.) storage tissue using 45 Ca 2+ . Uptake of 45 Ca 2+ by the vesicles was ATP-dependent and radiotracer accumulated by the vesicles could be released by the addition of the calcium ionophore A23187. The uptake was stimulated by gramicidin D but slightly inhibited by carbonylcyanide m-chlorophenylhydrazone. Although the latter result might suggest some degree of indirect coupling of 45 Ca 2+ uptake to ATP utilization via ΔμH + , no evidence for a secondary H + /Ca 2+ antiport in this vesicle system could be found. Following the imposition of an acid-interior pH gradient, proton efflux from the vesicle was not enhanced by the addition of Ca 2+ and an imposed pH gradient could not drive 45 Ca 2+ uptake. Optimal uptake of 45 Ca 2+ occurred broadly between pH 7.0 and 7.5 and the transport was inhibited by orthovanadate, N,N'-dicyclohexylcarbodiimide, and diethylstilbestrol but insensitive to nitrate and azide. The dependence of 45 Ca 2+ uptake on both calcium and Mg:ATP concentration demonstrated saturation kinetics with K/sub m/ values of 6 micromolar and 0.37 millimolar, respectively. While ATP was the preferred substrate for driving 45 Ca 2+ uptake, GTP could drive transport at about 50% of the level observed for ATP. The results of this study demonstrate the presence of a unique primary calcium transport system associated with the plasma membrane which could drive calcium efflux from the plant cell

Trifluoperazine-Induced Suicidal Erythrocyte Death and S-Nitrosylation Inhibition, Reversed by the Nitric Oxide Donor Sodium Nitroprusside

Directory of Open Access Journals (Sweden)

Mehrdad Ghashghaeinia

2017-08-01

Full Text Available Background and Purpose: The high potency antipsychotic drug trifluoperazine (10-[3-(4-methyl-1-piperazinyl-propyl]-2-(trifluoromethyl-(10H-phenothiazine dihydrochloride; TFP may either counteract or promote suicidal cell death or apoptosis. Similar to apoptosis, erythrocytes may enter eryptosis, characterized by phosphatidylserine exposure at the cell surface and cell shrinkage. Eryptosis can be stimulated by an increase in cytoplasmic Ca2+ concentration ([Ca2+]i and inhibited by nitric oxide (NO. We explored whether TFP treatment of erythrocytes induces phosphatidylserine exposure, cell shrinkage, and calcium influx, whether it impairs S-nitrosylation and whether these effects are inhibited by NO. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, and protein nitrosylation from fluorescence switch of the Bodipy-TMR/Sypro Ruby signal. Results: Exposure of human erythrocytes to TFP significantly enhanced the percentage of annexin-V-binding cells, raised [Ca2+]i, and decreased S-nitrosylation. The effect of TFP on annexin-V-binding was not affected by removal of extracellular Ca2+ alone, but was significantly inhibited by pre-treatment with sodium nitroprusside (SNP, an effect significantly augmented by additional removal of extracellular Ca2+. A 3 hours treatment with 0.1 µM Ca2+ ionophore ionomycin triggered annexin-V-binding and cell shrinkage, effects fully reversed by removal of extracellular Ca2+. Conclusions: TFP induces eryptosis and decreases protein S-nitrosylation, effects blunted by nitroprusside. The effect of nitroprusside is attenuated in the presence of extracellular Ca2+.

Demonstration of a specific C3a receptor on guinea pig platelets

International Nuclear Information System (INIS)

Fukuoka, Y.; Hugli, T.E.

1988-01-01

Guinea pig platelets reportedly contain receptors specific for the anaphylatoxin C3a based on both ligand-binding studies and functional responses. A portion of the human 125I-C3a that binds to guinea pig platelets is competitively displaced by excess unlabeled C3a; however, the majority of ligand uptake was nonspecific. Uptake of 125I-C3a by guinea pig platelets is maximal in 1 min, and stimulation of guinea pig platelets by thrombin, ADP, or the Ca2+ ionophore A23187 showed little influence on binding of the ligand. Scatchard analysis indicated that approximately 1200 binding sites for C3a exist per cell with an estimated Kd of 8 x 10(-10) M. Human C3a des Arg also binds to guinea pig platelets, but Scatchard analysis indicated that no specific binding occurred. Because the ligand-binding studies were complicated by high levels of nonspecific uptake, we attempted to chemically cross-link the C3a molecule to a specific component on the platelet surface. Cross-linkage of 125I-C3a to guinea pig platelets with bis(sulfosuccinimidyl)suberate revealed radioactive complexes at 105,000 and 115,000 m.w. on SDS-PAGE gels by autoradiographic analysis. In the presence of excess unlabeled C3a, complex formation was inhibited. No cross-linkage could be demonstrated between the inactive 125I-C3a des Arg and the putative C3a-R on guinea pig platelets. Human C3a, but not C3a des Arg induces serotonin release and aggregation of the guinea pig platelets. Human C3a was unable to induce either serotonin release or promote aggregation of human platelets. Uptake of human 125I-C3a by human platelets was not saturable, and Scatchard analysis was inconclusive. Attempts to cross-link 125I-C3a to components on the surface of human platelets also failed to reveal a ligand-receptor complex. Therefore, we conclude that guinea pig platelets have specific surface receptors to C3a and that human platelets appear devoid of receptors to the anaphylatoxin

The Ca(2+) status of the endoplasmic reticulum is altered by induction of calreticulin expression in transgenic plants

Science.gov (United States)

Persson, S.; Wyatt, S. E.; Love, J.; Thompson, W. F.; Robertson, D.; Boss, W. F.; Brown, C. S. (Principal Investigator)

2001-01-01

To investigate the endoplasmic reticulum (ER) Ca(2+) stores in plant cells, we generated tobacco (Nicotiana tabacum; NT1) suspension cells and Arabidopsis plants with altered levels of calreticulin (CRT), an ER-localized Ca(2+)-binding protein. NT1 cells and Arabidopsis plants were transformed with a maize (Zea mays) CRT gene in both sense and antisense orientations under the control of an Arabidopsis heat shock promoter. ER-enriched membrane fractions from NT1 cells were used to examine how altered expression of CRT affects Ca(2+) uptake and release. We found that a 2.5-fold increase in CRT led to a 2-fold increase in ATP-dependent (45)Ca(2+) accumulation in the ER-enriched fraction compared with heat-shocked wild-type controls. Furthermore, after treatment with the Ca(2+) ionophore ionomycin, ER microsomes from NT1 cells overproducing CRT showed a 2-fold increase in the amount of (45)Ca(2+) released, and a 2- to 3-fold increase in the amount of (45)Ca(2+) retained compared with wild type. These data indicate that altering the production of CRT affects the ER Ca(2+) pool. In addition, CRT transgenic Arabidopsis plants were used to determine if altered CRT levels had any physiological effects. We found that the level of CRT in heat shock-induced CRT transgenic plants correlated positively with the retention of chlorophyll when the plants were transferred from Ca(2+)-containing medium to Ca(2+)-depleted medium. Together these data are consistent with the hypothesis that increasing CRT in the ER increases the ER Ca(2+) stores and thereby enhances the survival of plants grown in low Ca(2+) medium.

The Ca2+ Status of the Endoplasmic Reticulum Is Altered by Induction of Calreticulin Expression in Transgenic Plants1

Science.gov (United States)

Persson, Staffan; Wyatt, Sarah E.; Love, John; Thompson, William F.; Robertson, Dominique; Boss, Wendy F.

2001-01-01

To investigate the endoplasmic reticulum (ER) Ca2+ stores in plant cells, we generated tobacco (Nicotiana tabacum; NT1) suspension cells and Arabidopsis plants with altered levels of calreticulin (CRT), an ER-localized Ca2+-binding protein. NT1 cells and Arabidopsis plants were transformed with a maize (Zea mays) CRT gene in both sense and antisense orientations under the control of an Arabidopsis heat shock promoter. ER-enriched membrane fractions from NT1 cells were used to examine how altered expression of CRT affects Ca2+ uptake and release. We found that a 2.5-fold increase in CRT led to a 2-fold increase in ATP-dependent 45Ca2+ accumulation in the ER-enriched fraction compared with heat-shocked wild-type controls. Furthermore, after treatment with the Ca2+ ionophore ionomycin, ER microsomes from NT1 cells overproducing CRT showed a 2-fold increase in the amount of 45Ca2+ released, and a 2- to 3-fold increase in the amount of 45Ca2+ retained compared with wild type. These data indicate that altering the production of CRT affects the ER Ca2+ pool. In addition, CRT transgenic Arabidopsis plants were used to determine if altered CRT levels had any physiological effects. We found that the level of CRT in heat shock-induced CRT transgenic plants correlated positively with the retention of chlorophyll when the plants were transferred from Ca2+-containing medium to Ca2+-depleted medium. Together these data are consistent with the hypothesis that increasing CRT in the ER increases the ER Ca2+ stores and thereby enhances the survival of plants grown in low Ca2+ medium. PMID:11457960

Optimal Method to Stimulate Cytokine Production and Its Use in Immunotoxicity Assessment

Directory of Open Access Journals (Sweden)

Huiming Chen

2013-08-01

Full Text Available Activation of lymphocytes can effectively produce a large amount of cytokines. The types of cytokines produced may depend on stimulating reagents and treatments. To find an optimal method to stimulate cytokine production and evaluate its effect on immunotoxicity assessments, the authors analyzed production of IL-2, IL-4, IL-6, IL-10, IL-13, IFN-γ, TNF-α, GM-CSF, RANTES and TGF-β in undiluted rat whole blood culture (incubation for 0, 2, 4, 6, 8 or 10 h with different concentrations of PMA/ionomycin, PHA, Con A, LPS and PWM. We also evaluated the effects of cyclosporin A and azathioprine on cytokine production. The results revealed a rapid increase of IL-2, IFN-γ, TNF-α, RANTES and TGF-β secretion within 6 h after stimulation with 25 ng/mL PMA and 1 μg/mL ionomycin. The inhibition of these cytokine profiles reflected the effects of immunosuppressants on the immune system. Therefore, the results of this is study recommend the detection of cytokine profiles in undiluted whole blood stimulated 6 h with 25 ng/mL PMA and 1 μg/mL ionomycin as a powerful immunotoxicity assessment method.

Lanthanide recognition: A Ho3+ potentiometric membrane sensor as a probe for determination of terazosin

International Nuclear Information System (INIS)

Ganjali, Mohammad Reza; Shams, Haniyeh; Faridbod, Farnoush; Hajiaghababaei, Leila; Norouzi, Parviz

2009-01-01

In this study, complexation of N'-(1-pyridin-2-ylmethylene)-2-furohydrazide (NFH) with some metal ions was investigated by conductometry and spectroscopy. Then, a Ho 3+ potentiometric membrane sensor was prepared based on the highly selective complexation between this ionophore and Ho 3+ . These new ionophores are more selective than the previously reported ones. In this work, for the first time, the proposed sensor was applied in indirect determination of the terazocine in its pharmaceutical formulation. The interest in constructing lanthanide sensors arises because they have similar ionic radii to calcium, but a higher charge density, which allows them to be used as probes to find the interactions between Ca 2+ and biologically important molecules.

Epoxide hydrolase-lasalocid a structure provides mechanistic insight into polyether natural product biosynthesis.

Science.gov (United States)

Wong, Fong T; Hotta, Kinya; Chen, Xi; Fang, Minyi; Watanabe, Kenji; Kim, Chu-Young

2015-01-14

Biosynthesis of some polyether natural products involves a kinetically disfavored epoxide-opening cyclic ether formation, a reaction termed anti-Baldwin cyclization. One such example is the biosynthesis of lasalocid A, an ionophore antibiotic polyether. During lasalocid A biosynthesis, an epoxide hydrolase, Lsd19, converts the bisepoxy polyketide intermediate into the tetrahydrofuranyl-tetrahydropyran product. We report the crystal structure of Lsd19 in complex with lasalocid A. The structure unambiguously shows that the C-terminal domain of Lsd19 catalyzes the intriguing anti-Baldwin cyclization. We propose a general mechanism for epoxide selection by ionophore polyether epoxide hydrolases.

Mast cells dysregulate apoptotic and cell cycle genes in mucosal squamous cell carcinoma

Directory of Open Access Journals (Sweden)

Davis Paul

2006-12-01

Full Text Available Abstract Background Mucosal squamous cell carcinoma of the head and neck is a disease of high mortality and morbidity. Interactions between the squamous cell carcinoma and the host's local immunity, and how the latter contributes to the biological behavior of the tumor are unclear. In vivo studies have demonstrated sequential mast cell infiltration and degranulation during squamous cell carcinogenesis. The degree of mast cell activation correlates closely with distinct phases of hyperkeratosis, dysplasia, carcinoma in-situ and invasive carcinoma. However, the role of mast cells in carcinogenesis is unclear. Aim This study explores the effects of mast cells on the proliferation and gene expression profile of mucosal squamous cell carcinoma using human mast cell line (HMC-1 and human glossal squamous cell carcinoma cell line (SCC25. Methods HMC-1 and SCC25 were co-cultured in a two-compartment chamber, separated by a polycarbonate membrane. HMC-1 was stimulated to degranulate with calcium ionophore A23187. The experiments were done in quadruplicate. Negative controls were established where SCC25 were cultured alone without HMC-1. At 12, 24, 48 and 72 hours, proliferation and viability of SCC25 were assessed with MTT colorimetric assay. cDNA microarray was employed to study differential gene expression between co-cultured and control SCC25. Results HMC-1/SCC25 co-culture resulted in suppression of growth rate for SCC-25 (34% compared with 110% for the control by 72 hours, p Conclusion We show that mast cells have a direct inhibitory effect on the proliferation of mucosal squamous cell carcinoma in vitro by dysregulating key genes in apoptosis and cell cycle control.

F NMR measurement of intracellular free calcium in human red blood cells

International Nuclear Information System (INIS)

Gupta, R.K.; Schanne, F.A.X.

1986-01-01

Optical techniques for the measurement of intracellular Ca are not readily applicable to the human red cell because of the intense absorption of hemoglobin. The authors have therefore examined the use of 19 F NMR of 5,5'-difluoro-1,2-bis(o-aminophenoxy) ethane-N,N,N',N'-tetra acetic acid (5FBAPTA) introduced non-disruptively by intracellular hydrolysis of the membrane-permeant acetoxymethyl ester derivative. 19 F NMR spectra of 5FBAPTA-containing erythrocytes at 188 MHz displayed two well resolved resonances corresponding to the free and Ca-bound forms of the chelator, the resonance of the free form being ten-fold larger than that of the Ca-bound form. Addition of the ionophore A23187 resulted in the disappearance of the resonance of the free anion and a quantitative increase in the intensity of the resonance of the Ca-complex. From these data, and a K/sub D/ of 708 nM for the Ca-5FBAPTA complex, the authors estimate red cell free Ca to be 70 nM, which is in the range of values obtained for other cells, despite the fact that the human red cell, which lacks intracellular organelles for storing Ca, possesses only 1 μmol total Ca/1. cells in comparison to mmols of total Ca found in other cells. The authors ability to use 19 F NMR to measure free Ca in the red blood cell paves the way for future NMR studies of red cell free Ca concentrations in human essential hypertension as well as in other diseases states in which alterations in cellular Ca homeostasis may be involved

Selection and characterization of T-cell variants lacking molecules involved in T-cell activation (T3 T-cell receptor, T44, and T11): analysis of the functional relationship among different pathways of activation

International Nuclear Information System (INIS)

Moretta, A.; Poggi, A.; Olive, D.; Bottino, C.; Fortis, C.; Pantaleo, G.; Moretta, L.

1987-01-01

A clone of the interleukin 2-producing Jurkat leukemia cell line termed JA3 (surface phenotype, T3 + , Ti + , T44 + , T11 + , T40 + ) has been used to induce and select cell variants lacking surface molecules involved in T-cell activation. Following 200 rad of γ-radiation (1 rad = 0.01 Gy), cells were treated with monoclonal antibodies (mAbs) directed to T3, Ti, T44, or T11 antigen and complement. After growth of the residual cells in culture, negative cells were cloned under limiting conditions. Depending on the specificity of the mAb used for the immunoselection, three groups of variants were obtained. (i) The use of mAbs directed to T3 or Ti resulted in cell variants that expressed the T3 - Ti - T44 + Leu1 + T11 + T40 + 4F2 + HLA class I + surface phenotype. (ii) Immunoselection with anti-T44 mAb resulted in 2 variants that shared the T3 - Ti - T44 - Leu1 - T11 - T40 - 4F2 - HLA class I + phenotype. (iii) Cell treatment with anti-T11 mAb resulted in 15 variants characterized by the lack of T11 antigen expression and of all the other T-cell-specific surface antigens. Therefore, it appears that the different sets of JA3 cell variants, like T cells at discrete stages of intrathymic differentiation, may follow a coordinated expression of surface differentiation antigens. Analysis of the functional responsiveness of the three distinct groups of JA3 cell variants to different stimuli showed that all produced interleukin 2 in response to A23187 calcium ionophore plus phorbol 12-myristate 13-acetate

Triggering of Suicidal Erythrocyte Death by Regorafenib

Directory of Open Access Journals (Sweden)

Jens Zierle

2016-01-01

Full Text Available Background/Aims: The multikinase inhibitor regorafenib is utilized for the treatment of malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Side effects of regorafenib include anemia. At least in theory, regorafenib induced anemia could result from stimulated suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and ceramide. The present study explored, whether regorafenib induces eryptosis and, if so, whether it is effective up- and/or downstream of Ca2+. Methods: To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to regorafenib (≥ 0.5 µg/ml significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (≥ 1.25 µg/ml, but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of regorafenib on annexin-V-binding and forward scatter was not significantly blunted by removal of extracellular Ca2+. Regorafenib (5 µg/ml significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin. Conclusions: Regorafenib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+.

Triggering of Suicidal Erythrocyte Death by Regorafenib.

Science.gov (United States)

Zierle, Jens; Bissinger, Rosi; Bouguerra, Ghada; Abbès, Salem; Lang, Florian

2016-01-01

The multikinase inhibitor regorafenib is utilized for the treatment of malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Side effects of regorafenib include anemia. At least in theory, regorafenib induced anemia could result from stimulated suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study explored, whether regorafenib induces eryptosis and, if so, whether it is effective up- and/or downstream of Ca2+. To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. A 48 hours exposure of human erythrocytes to regorafenib (≥ 0.5 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (≥ 1.25 µg/ml), but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of regorafenib on annexin-V-binding and forward scatter was not significantly blunted by removal of extracellular Ca2+. Regorafenib (5 µg/ml) significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin. Regorafenib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+. © 2016 The Author(s) Published by S. Karger AG, Basel.

Proteomic identification of S-nitrosylated Golgi proteins: new insights into endothelial cell regulation by eNOS-derived NO.

Directory of Open Access Journals (Sweden)

Panjamaporn Sangwung

Full Text Available Endothelial nitric oxide synthase (eNOS is primarily localized on the Golgi apparatus and plasma membrane caveolae in endothelial cells. Previously, we demonstrated that protein S-nitrosylation occurs preferentially where eNOS is localized. Thus, in endothelial cells, Golgi proteins are likely to be targets for S-nitrosylation. The aim of this study was to identify S-nitrosylated Golgi proteins and attribute their S-nitrosylation to eNOS-derived nitric oxide in endothelial cells.Golgi membranes were isolated from rat livers. S-nitrosylated Golgi proteins were determined by a modified biotin-switch assay coupled with mass spectrometry that allows the identification of the S-nitrosylated cysteine residue. The biotin switch assay followed by Western blot or immunoprecipitation using an S-nitrosocysteine antibody was also employed to validate S-nitrosylated proteins in endothelial cell lysates.Seventy-eight potential S-nitrosylated proteins and their target cysteine residues for S-nitrosylation were identified; 9 of them were Golgi-resident or Golgi/endoplasmic reticulum (ER-associated proteins. Among these 9 proteins, S-nitrosylation of EMMPRIN and Golgi phosphoprotein 3 (GOLPH3 was verified in endothelial cells. Furthermore, S-nitrosylation of these proteins was found at the basal levels and increased in response to eNOS stimulation by the calcium ionophore A23187. Immunofluorescence microscopy and immunoprecipitation showed that EMMPRIN and GOLPH3 are co-localized with eNOS at the Golgi apparatus in endothelial cells. S-nitrosylation of EMMPRIN was notably increased in the aorta of cirrhotic rats.Our data suggest that the selective S-nitrosylation of EMMPRIN and GOLPH3 at the Golgi apparatus in endothelial cells results from the physical proximity to eNOS-derived nitric oxide.

Omega-oxidation is the major pathway for the catabolism of leukotriene B4 in human polymorphonuclear leukocytes.

Science.gov (United States)

Shak, S; Goldstein, I M

1984-08-25

Leukotriene B4 (LTB4), formed by the 5-lipoxygenase pathway in human polymorphonuclear leukocytes (PMN), may be an important mediator of inflammation. Recent studies suggest that human leukocytes can convert LTB4 to products that are less biologically active. To examine the catabolism of LTB4, we developed (using high performance liquid chromatography) a sensitive, reproducible assay for this mediator and its omega-oxidation products (20-OH- and 20-COOH-LTB4). With this assay, we have found that human PMN (but not human monocytes, lymphocytes, or platelets) convert exogenous LTB4 almost exclusively to 20-OH- and 20-COOH-LTB4 (identified by gas chromatography-mass spectrometry). Catabolism of exogenous LTB4 by omega-oxidation is rapid (t1/2 approximately 4 min at 37 degrees C in reaction mixtures containing 1.0 microM LTB4 and 20 X 10(6) PMN/ml), temperature-dependent (negligible at 0 degrees C), and varies with cell number as well as with initial substrate concentration. The pathway for omega-oxidation in PMN is specific for LTB4 and 5(S),12(S)-dihydroxy-6,8,10,14-eicosatetraenoic acid (only small amounts of other dihydroxylated-derivatives of arachidonic acid are converted to omega-oxidation products). Even PMN that are stimulated by phorbol myristate acetate to produce large amounts of superoxide anion radicals catabolize exogenous leukotriene B4 primarily by omega-oxidation. Finally, LTB4 that is generated when PMN are stimulated with the calcium ionophore, A23187, is rapidly catabolized by omega-oxidation. Thus, human PMN not only generate and respond to LTB4, but also rapidly and specifically catabolize this mediator by omega-oxidation.

Cornuside inhibits mast cell-mediated allergic response by down-regulating MAPK and NF-κB signaling pathways

Energy Technology Data Exchange (ETDEWEB)

Li, Liangchang [Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Yanbian University, Yanji, 133002 (China); Jin, Guangyu [Yanbian University Hospital, Medicine College, Yanbian University, Yanji, 133000 (China); Jiang, Jingzhi [Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Yanbian University, Yanji, 133002 (China); Zheng, Mingyu; Jin, Yan [College of Pharmacy, Yanbian University, Yanji, 133002 (China); Lin, Zhenhua [Department of Pathology & Cancer Research Center, Yanbian University Medical College, Yanji, 133002 (China); Li, Guangzhao [Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Yanbian University, Yanji, 133002 (China); Choi, Yunho, E-mail: why76@jbnu.ac.kr [Department of Anatomy, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Yan, Guanghai, E-mail: ghyan2015@sina.com [Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Yanbian University, Yanji, 133002 (China)

2016-04-29

Aims: The present study is to investigate the effect of cornuside on mast cell-mediated allergic response, as well as its possible mechanisms of action. Methods: To test the anti-allergic effects of cornuside in vivo, local extravasation was induced by local injection of anti-dinitrophenyl immunoglobulin E (IgE) followed by intravenous antigenic challenge in passive cutaneous anaphylaxis model rats. Mast cell viability was determined using MTT assay. Histamine content from rat peritoneal mast cells was measured by the radioenzymatic method. To investigate the mechanisms by which cornuside affects the reduction of histamine release, the levels of calcium uptake were measured. To examine whether cornuside affects the expression of pro-inflammatory cytokines, Western blotting and ELISA were carried out. Results: Oral administration of cornuside inhibited passive cutaneous anaphylaxis in rats. Presence of cornuside attenuated IgE-induced histamine release from rat peritoneal mast cells. The inhibitory effect of cornuside on histamine release was mediated by the modulation of intracellular calcium. In addition, cornuside decreased phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187-stimulated production and secretion of pro-inflammatory cytokines such as TNF-α and IL-6 in human mast cells. The inhibitory effect of cornuside on pro-inflammatory cytokines was dependent on nuclear factor-κB and p38 mitogen-activated protein kinase. Conclusions: The present study provides evidence that cornuside inhibits mast cell-derived inflammatory allergic reactions by blocking histamine release and pro-inflammatory cytokine expression. Furthermore, in vivo and in vitro anti-allergic effects of cornuside suggest a possible therapeutic application of this agent in inflammatory allergic diseases.

Cornuside inhibits mast cell-mediated allergic response by down-regulating MAPK and NF-κB signaling pathways

International Nuclear Information System (INIS)

Li, Liangchang; Jin, Guangyu; Jiang, Jingzhi; Zheng, Mingyu; Jin, Yan; Lin, Zhenhua; Li, Guangzhao; Choi, Yunho; Yan, Guanghai

2016-01-01

Aims: The present study is to investigate the effect of cornuside on mast cell-mediated allergic response, as well as its possible mechanisms of action. Methods: To test the anti-allergic effects of cornuside in vivo, local extravasation was induced by local injection of anti-dinitrophenyl immunoglobulin E (IgE) followed by intravenous antigenic challenge in passive cutaneous anaphylaxis model rats. Mast cell viability was determined using MTT assay. Histamine content from rat peritoneal mast cells was measured by the radioenzymatic method. To investigate the mechanisms by which cornuside affects the reduction of histamine release, the levels of calcium uptake were measured. To examine whether cornuside affects the expression of pro-inflammatory cytokines, Western blotting and ELISA were carried out. Results: Oral administration of cornuside inhibited passive cutaneous anaphylaxis in rats. Presence of cornuside attenuated IgE-induced histamine release from rat peritoneal mast cells. The inhibitory effect of cornuside on histamine release was mediated by the modulation of intracellular calcium. In addition, cornuside decreased phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187-stimulated production and secretion of pro-inflammatory cytokines such as TNF-α and IL-6 in human mast cells. The inhibitory effect of cornuside on pro-inflammatory cytokines was dependent on nuclear factor-κB and p38 mitogen-activated protein kinase. Conclusions: The present study provides evidence that cornuside inhibits mast cell-derived inflammatory allergic reactions by blocking histamine release and pro-inflammatory cytokine expression. Furthermore, in vivo and in vitro anti-allergic effects of cornuside suggest a possible therapeutic application of this agent in inflammatory allergic diseases.

Evidence that CFTR is expressed in rat tracheal smooth muscle cells and contributes to bronchodilation

Directory of Open Access Journals (Sweden)

Mettey Yvette

2006-08-01

Full Text Available Abstract Background The airway functions are profoundly affected in many diseases including asthma, chronic obstructive pulmonary disease (COPD and cystic fibrosis (CF. CF the most common lethal autosomal recessive genetic disease is caused by mutations of the CFTR gene, which normally encodes a multifunctional and integral membrane protein, the CF transmembrane conductance regulator (CFTR expressed in airway epithelial cells. Methods To demonstrate that CFTR is also expressed in tracheal smooth muscle cells (TSMC, we used iodide efflux assay to analyse the chloride transports in organ culture of rat TSMC, immunofluorescence study to localize CFTR proteins and isometric contraction measurement on isolated tracheal rings to observe the implication of CFTR in the bronchodilation. Results We characterized three different pathways stimulated by the cAMP agonist forskolin and the isoflavone agent genistein, by the calcium ionophore A23187 and by hypo-osmotic challenge. The pharmacology of the cAMP-dependent iodide efflux was investigated in detail. We demonstrated in rat TSMC that it is remarkably similar to that of the epithelial CFTR, both for activation (using three benzo [c]quinolizinium derivatives and for inhibition (glibenclamide, DPC and CFTRinh-172. Using rat tracheal rings, we observed that the activation of CFTR by benzoquinolizinium derivatives in TSMC leads to CFTRinh-172-sensitive bronchodilation after constriction with carbachol. An immunolocalisation study confirmed expression of CFTR in tracheal myocytes. Conclusion Altogether, these observations revealed that CFTR in the airways of rat is expressed not only in the epithelial cells but also in tracheal smooth muscle cells leading to the hypothesis that this ionic channel could contribute to bronchodilation.

Enhanced incorporation of fatty acid into phosphatidyl choline that parallels histamine discharge in mast cells

International Nuclear Information System (INIS)

Castle, J.D.; Castle, A.M.; Ma, A.K.; Stukenbrok, H.

1984-01-01

Purified rat peritoneal and pleural mast cells preincubated briefly with radioactively labeled fatty acid were treated with A23187, which bypasses primary receptors in stimulating exocytosis. An enhanced incorporation of fatty acid into phosphatidyl choline (PC) that occurred in parallel with histamine release at 24-25 degrees C was observed and was initially proportional to the total amount of histamine discharged. Enhanced PC labeling and histamine secretion were also proportional at temperatures ranging from 17-37 degrees C. Both radioactive linoleic and palmitic acids were incorporated selectively at the beta-position of the glycerol backbone of PC. PC labeling by [3H]choline was not detectably different in control and stimulated cells, and phosphatidic acid did not exhibit selectively enhanced beta-acylation. Thus, the stimulated labeling in A23187-treated cells may occur secondary to the action of a phospholipase A2 that favors PC as a substrate. Other peritoneal cell types exhibit a very similar A23187-stimulated selective labeling of PC. Therefore, autoradiography has been used to provide a direct demonstration that in purified preparations, mast cells are the principal cell type engaged in A23187-elicited incorporation of fatty acid into PC. The efficacy of this approach has relied on special procedures devised to obtain significantly different autoradiographic grain densities between control and stimulated preparations that can be attributed to differences in the level of [3H]palmitate-labeled PC. Preliminary tests using compound 48/80 as a secretory stimulus for mast cells have identified a similar selectively enhanced PC labeling. In either case, however, consideration of possible relationships between PC metabolism and the secretory process are premature since they have not been tested directly

Effects of an Ionophore Coccidiostat (Monensin or Salinomycin, Sodium or Potassium Bicarbonate, or Both, and Bacitracin Methylene Disalicylate in Broiler Chicken Diets

Directory of Open Access Journals (Sweden)

Hooge DM

2000-01-01

Full Text Available Peterson x Arbor Acres chicks were grown on used litter to 45 or 46 days of age in three pen trials. Coccidial inoculations were given by water at 14 days of age. Sodium bicarbonate (SBC; 0.20% or potassium bicarbonate (PBC; 0.14% was added to broiler chicken diets containing monensin (MON; 110 mg/kg or salinomycin (SAL; 66 mg/kg in Experiment 1. In Experiment 2, using SAL (55 mg/kg, three dietary bicarbonate treatments (SBC, 0.20%; PBC, 0.20%; or SBC + PBC 0.10% each were tested with or without BMD R (55 mg/kg. Diets differing in SAL, BMD R, and SBC levels were evaluated in Experiment 3. Beneficial interaction was found between ionophores and bicarbonates for mortality (lower when SBC or PBC and MON in Experiment 1. For main effects, in Experiment 1 PBC with MON or SAL improved body weight, feed conversion ratio and mortality. SAL improved weight, feed conversion ratio and mortality compared to MON. In Experiment 2, PBC with SAL improved weight, coccidial lesion score, feed conversion ratio and mortality across two levels of BMD R. The PBC and SBC were equally effective in Experiment 1, but PBC was about 0 to 40% as effective as SBC, depending on parameter in Experiment 2. Half levels of SBC plus PBC generally gave intermediate results between control and SBC. SBC with MON or SAL lowered mortalities, coccidial lesion scores, and feed conversion ratios (Experiments 1 and 2, and increased body weight (Experiment 2. In Experiment 3, BMD R in all feeds improved body weight and feed conversion versus in starter feed only, and SBC with SAL and BMD R improved all performance parameters.

Restoration of prostaglandin E2-producing splenic macrophages in 89Sr-treated mice with bone marrow from Corynebacterium parvum primed donors

International Nuclear Information System (INIS)

Shibata, Y.

1989-01-01

Administration of Corynebacterium parvum (CP), 56 mg/kg ip to CBA/J mice effected the induction of prostaglandin E2 (PGE2) producing macrophages (M phi) in the bone marrow and the spleen. Maximal release of PGE2 from M phi cultured in vitro with calcium ionophore A23187 for 2 h was reached by marrow M phi removed on 5 days after CP (450 ng/mg cell protein), and by splenic M phi 9 days after CP (400 ng/mg). Neither M phi population, however, yielded more than 6.0 ng/mg leukotriene C4. To assess ontogenic relationships mice were depleted of bone marrow and blood monocytes by iv injection of the bone-seeking isotope, 89Sr. CP was given at several points before or after bone marrow cell depletion. PGE2 production by splenic M phi harvested on day 9 after CP was profoundly impaired when CP was administered either concurrently with or 3 days after 89Sr. When CP was administered 1, 3, 5, and 7 days before 89Sr, however, the induction of PGE2-producing M phi in the spleen was unaffected. To determine whether bone marrow cells from CP-injected donors can restore PGE2-producing splenic M phi (PGSM) in 89Sr-mice, recipient mice which had and had not received CP 3 days after 89Sr were transfused with 5 x 10(6) syngeneic bone marrow cells from donor mice prepared at varying intervals after CP administration. The results clearly indicate the capacity of bone marrow cells harvested on either day 1 or 2 following CP to restore PGSM in CP-primed, but not unprimed, recipients

Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: application to sulfamethoxazole and trimethoprim.

Science.gov (United States)

Almeida, S A A; Arasa, E; Puyol, M; Martinez-Cisneros, C S; Alonso-Chamarro, J; Montenegro, M C B S M; Sales, M G F

2011-12-15

Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices to carry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/μPOT) was developed for the first time for an organic compound: sulfamethoxazole (SMX). Sensory materials relied on newly designed plastic antibodies. Sol-gel, self-assembling monolayer and molecular-imprinting techniques were merged for this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conducted around SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were used as ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysis was verified in flow-injection studies with regular tubular electrodes. The LTCC/μPOT device integrated a bidimensional mixer, an embedded reference electrode based on Ag/AgCl and an Ag-based contact screen-printed under a micromachined cavity of 600 μm depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Under optimum conditions, the SMX sensor displayed slopes of about -58.7 mV/decade in a range from 12.7 to 250 μg/mL, providing a detection limit of 3.85 μg/mL and a sampling throughput of 36 samples/h with a reagent consumption of 3.3 mL per sample. The system was adjusted later to multiple analyte detection by including a second potentiometric cell on the LTCC/μPOT device. No additional reference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, and tested in fish-farming waters. The biparametric microanalyzer displayed Nernstian behaviour, with average slopes -54.7 (SMX) and +57.8 (TMP) m

A selective potentiometric copper (II) ion sensor based on the functionalized ZnO nanorods.

Science.gov (United States)

Khun, K; Ibupoto, Z H; Liu, X; Nur, O; Willander, M; Danielsson, B

2014-09-01

In this work, ZnO nanorods were hydrothermally grown on the gold-coated glass substrate and characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The ZnO nanorods were functionalized by two different approaches and performance of the sensor electrode was monitored. Fourier transform infrared spectroscopy (FTIR) was carried out for the confirmation of interaction between the ionophore molecules and ZnO nanorods. In addition to this, the surface of the electrode was characterized by X-ray photoelectron spectroscopy (XPS) showing the chemical and electronic state of the ionophore and ZnO nanorod components. The ionophore solution was prepared in the stabilizer, poly vinyl chloride (PVC) and additives, and then functionalized on the ZnO nanorods that have shown the Nernstian response with the slope of 31 mV/decade. However, the Cu2+ ion sensor was fabricated only by immobilizing the selective copper ion ionophore membrane without the use of PVC, plasticizers, additives and stabilizers and the sensor electrode showed a linear potentiometric response with a slope of 56.4 mV/decade within a large dynamic concentration range (from 1.0 x 10(-6) to 1.0 x 10(-1) M) of copper (II) nitrate solutions. The sensor showed excellent repeatability and reproducibility with response time of less than 10 s. The negligible response to potentially interfering metal ions such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe3+), zinc (Zn2+), and sodium (Na+) allows this sensor to be used in biological studies. It may also be used as an indicator electrode in the potentiometric titration.

Clofazimine Induced Suicidal Death of Human Erythrocytes

Directory of Open Access Journals (Sweden)

Arbace Officioso

2015-08-01

Full Text Available Background/Aims: The antimycobacterial riminophenazine clofazimine has previously been shown to up-regulate cellular phospholipase A2 and to induce apoptosis. In erythrocytes phospholipase A2 stimulates eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Phospholipase A2 is in part effective by fostering formation of prostaglandin E2, which triggers Ca2+ entry. Stimulators of Ca2+ entry and eryptosis further include oxidative stress and energy depletion. The present study tested, whether and how clofazimine induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, hemolysis from hemoglobin release, cytosolic Ca2+ activity ([Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS from 2′, 7′-dichlorodihydrofluorescein diacetate (DCFDA fluorescence, and cytosolic ATP level utilizing a luciferin-luciferase assay kit. Results: A 24-48 hours exposure of human erythrocytes to clofazimine (≥1.5 µg/ml significantly increased the percentage of annexin-V-binding cells without appreciably modifying forward scatter. Clofazimine significantly increased [Ca2+]i, significantly decreased cytosolic ATP, but did not significantly modify ROS. The effect of clofazimine on annexin-V-binding was significantly blunted, but not fully abolished by removal of extracellular Ca2+, and by phospholipase A2 inhibitor quinacrine (25 µM. Clofazimine further augmented the effect of Ca2+ ionophore ionomycin (0.1 µM on eryptosis. The clofazimine induced annexin-V-binding was, however, completely abrogated by combined Ca2+ removal and addition of quinacrine. Conclusion: Clofazimine stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect in part dependent on entry of extracellular Ca2+, paralleled by cellular energy depletion and sensitive to

Cloning and regulation of rat tissue inhibitor of metalloproteinases-2 in osteoblastic cells

Science.gov (United States)

Cook, T. F.; Burke, J. S.; Bergman, K. D.; Quinn, C. O.; Jeffrey, J. J.; Partridge, N. C.

1994-01-01

Rat tissue inhibitor of metalloproteinases-2 (TIMP-2) was cloned from a UMR 106-01 rat osteoblastic osteosarcoma cDNA library. The 969-bp full-length clone demonstrates 98 and 86% sequence identity to human TIMP-2 at the amino acid and nucleic acid levels, respectively. Parathyroid hormone (PTH), at 10(-8) M, stimulates an approximately twofold increase in both the 4.2- and 1.0-kb transcripts over basal levels in UMR cells after 24 h of exposure. The PTH stimulation of TIMP-2 transcripts was not affected by the inhibitor of protein synthesis, cycloheximide (10(-5) M), suggesting a primary effect of the hormone. This is in contradistinction to regulation of interstitial collagenase (matrix metalloproteinase-1) by PTH in these same cells. Nuclear run-on assays demonstrate that PTH causes an increase in TIMP-2 transcription that parallels the increase in message levels. Parathyroid hormone, in its stimulation of TIMP-2 mRNA, appears to act through a signal transduction pathway involving protein kinase A (PKA) since the increase in TIMP-2 mRNA is reproduced by treatment with the cAMP analogue, 8-bromo-cAMP (5 x 10(-3) M). The protein kinase C and calcium pathways do not appear to be involved due to the lack of effect of phorbol 12-myristate 13-acetate (2.6 x 10(-6) M) and the calcium ionophore, ionomycin (10(-7) M), on TIMP-2 transcript abundance. In this respect, regulation of TIMP-2 and collagenase in osteoblastic cells by PTH are similar. However, we conclude that since stimulation of TIMP-2 transcription is a primary event, the PKA pathway must be responsible for a direct increase in transcription of this gene.

Modulation of the release of norepinephrine by gamma-aminobutyric acid and morphine in the frontal cerebral cortex of the rat

International Nuclear Information System (INIS)

Peoples, R.W.

1989-01-01

Agents that enhance gamma-aminobutyric acid, or GABA, neurotransmission modulate certain effects of opioids, such as analgesia. Opioid analgesia is mediated in part by norepinephrine in the forebrain. In this study, the interactions between morphine and GABAergic agents on release of [ 3 H] norepinephrine from rat frontal cerebral cortical slices were examined. GABA, 5 x 10 -5 -10 -3 M, enhanced potassium stimulated [ 3 H] norepinephrine release and reversed the inhibitory effect of morphine in a noncompetitive manner. GABA did not enhance release of [ 3 H] norepinephrine stimulated by the calcium ionophore A23187. The effect of GABA was reduced by the GABA A receptor antagonists bicuculline methiodide or picrotoxin, and by the selective inhibitor of GABA uptake SKF 89976A, but was blocked completely only when bicuculline methiodide and SKF 89976A were used in combination. The GABA A agonist muscimol, 10 -4 M, mimicked the effect of GABA, but the GABA B agonist (±)baclofen, 10 -4 M, did not affect the release of [ 3 H] norepinephrine in the absence or the presence of morphine. Thus GABA appears to produce this effect by stimulating GABA uptake and GABA A , but not GABA B , receptors. In contrast to the results that would be predicted for an event involving GABA A receptors, however, the effect of GABA did not desensitize, and benzodiazepine agonists did not enhance the effect of GABA at any concentration tested between 10 -8 and 10 -4 M. Thus these receptors may constitute a subclass of GABA A receptors. These results support a role of GABA uptake and GABA A receptors in enhancing the release of norepinephrine and modulating its inhibition by opioids in the frontal cortex of the rat

Modulation of the release of norepinephrine by gamma-aminobutyric acid and morphine in the frontal cerebral cortex of the rat

Energy Technology Data Exchange (ETDEWEB)

Peoples, R.W.

1989-01-01

Agents that enhance gamma-aminobutyric acid, or GABA, neurotransmission modulate certain effects of opioids, such as analgesia. Opioid analgesia is mediated in part by norepinephrine in the forebrain. In this study, the interactions between morphine and GABAergic agents on release of ({sup 3}H) norepinephrine from rat frontal cerebral cortical slices were examined. GABA, 5 {times} 10{sup {minus}5}-10{sup {minus}3} M, enhanced potassium stimulated ({sup 3}H) norepinephrine release and reversed the inhibitory effect of morphine in a noncompetitive manner. GABA did not enhance release of ({sup 3}H) norepinephrine stimulated by the calcium ionophore A23187. The effect of GABA was reduced by the GABA{sub A} receptor antagonists bicuculline methiodide or picrotoxin, and by the selective inhibitor of GABA uptake SKF 89976A, but was blocked completely only when bicuculline methiodide and SKF 89976A were used in combination. The GABA{sub A} agonist muscimol, 10{sup {minus}4} M, mimicked the effect of GABA, but the GABA{sub B} agonist ({plus minus})baclofen, 10{sup {minus}4} M, did not affect the release of ({sup 3}H) norepinephrine in the absence or the presence of morphine. Thus GABA appears to produce this effect by stimulating GABA uptake and GABA{sub A}, but not GABA{sub B}, receptors. In contrast to the results that would be predicted for an event involving GABA{sub A} receptors, however, the effect of GABA did not desensitize, and benzodiazepine agonists did not enhance the effect of GABA at any concentration tested between 10{sup {minus}8} and 10{sup {minus}4} M. Thus these receptors may constitute a subclass of GABA{sub A} receptors. These results support a role of GABA uptake and GABA{sub A} receptors in enhancing the release of norepinephrine and modulating its inhibition by opioids in the frontal cortex of the rat.

A Novel Sensor for Monitoring of Iron(III) Ions Based on Porphyrins

Science.gov (United States)

Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

2012-01-01

Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples. PMID:22969395

A novel sensor for monitoring of iron(III) ions based on porphyrins.

Science.gov (United States)

Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

2012-01-01

Three A(3)B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10(-7)-1 × 10(-1) M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples.

Oocyte activation and preimplantation development of bovine embryos obtained by specific inhibition of cyclin-dependent kinases Ativação oocitária e desenvolvimento pré-implantação de embriões bovinos obtidos com o uso de inibidores específicos das quinases dependentes de ciclina

Directory of Open Access Journals (Sweden)

F. Perecin

2007-04-01

Full Text Available The efficiency of bohemine and roscovitine in combination with ionomycin on parthenogenetic activation and initial embryonic development of bovine oocytes was studied. Two experiments were performed: in the first, different concentrations (0, 50, 75 or 100µM and different exposure periods (2, 4 or 6 hours to bohemine or roscovitine were tested for activation rates of in vitro matured (IVM bovine oocytes, which were pre-exposed to ionomycin. The best treatments, 75µM bohemine and 50µM roscovitine, both for 6h, were used in the second experiment, in which IVM bovine oocytes were exposed to ionomycin, followed or not by bohemine or roscovitine treatment, and evaluated for nuclear status, activation rate and blastocyst development were assessed. The combined treatments (ionomycin + cyclin-dependent kinases inhibitors - CDKIs showed better results for activation rates (77.3% and initial embryonic development (35.2% than the single ionomycin treatment (69.4% for activation and 21.9% for development; and also lead to a more uniform activation (nearly 90% single pronucleus development. The results showed that CDKIs improve the effects of ionomycin on parthenogenetic activation and blastocyst development in bovine oocytes and could help to achieve more efficient activation protocols, increasing the developmental competence of embryos obtained by reproductive biotechniques.Realizaram-se dois experimentos para avaliar a eficiência da bohemina e roscovitina associadas à ionomicina para ativação partenogenética e desenvolvimento embrionário inicial de bovinos. No primeiro, foram testadas diferentes concentrações (0, 50, 75 ou 100µM e diferentes tempos de exposição (2, 4 ou 6 horas à bohemina ou à roscovitina na ativação de oócitos bovinos maturados in vitro (MIV pré-expostos à ionomicina. Os melhores tratamentos, bohemina 75µM e roscovitina 50µM, ambos por seis horas, foram utilizados no segundo experimento, no qual oócitos bovinos

Parathyroid hormone promotes the disassembly of cytoskeletal actin and myosin in cultured osteoblastic cells: Mediation by cyclic AMP

International Nuclear Information System (INIS)

Egan, J.J.; Gronowicz, G.; Rodan, G.A.

1991-01-01

Parathyroid hormone (PTH) alters the shape of osteoblastic cells both in vivo and in vitro. In this study, we examined the effect of PTH on cytoskeletal actin and myosin, estimated by polyacrylamide gel electrophoresis of Triton X-100 (1%) nonextractable proteins. After 2-5 minutes, PTH caused a rapid and transient decrease of 50-60% in polymerized actin and myosin associated with the Triton X-100 nonextractable cytoskeleton. Polymerized actin returned to control levels by 30 min. The PTH effect was dose-dependent with an IC50 of about 1 nM, and was partially inhibited by the (3-34) PTH antagonist. PTH caused a rapid transient rise in cyclic AMP (cAMP) in these cells that peaked at 4 min, while the nadir in cytoskeletal actin and myosin was recorded around 5 min. The intracellular calcium chelator Quin-2/AM (10 microM) also decreased cytoskeletal actin and myosin, to the same extent as did PTH (100 nM). To distinguish between cAMP elevation and Ca++ reduction as mediators of PTH action, we measured the phosphorylation of the 20 kD (PI 4.9) myosin light chain in cells preincubated with [32P]-orthophosphate. The phosphorylation of this protein decreased within 2-3 min after PTH addition and returned to control levels after 5 min. The calcium ionophore A-23187 did not antagonize this PTH effect. Visualization of microfilaments with rhodamine-conjugated phalloidin showed that PTH altered the cytoskeleton by decreasing the number of stress fibers. These changes in the cytoskeleton paralleled changes in the shape of the cells from a spread configuration to a stellate form with retracting processes. The above findings indicate that the alteration in osteoblast shape produced by PTH involve relatively rapid and transient changes in cytoskeletal organization that appear to be mediated by cAMP

Synthetic peptides corresponding to human follicle-stimulating hormone (hFSH)-beta-(1-15) and hFSH-beta-(51-65) induce uptake of 45Ca++ by liposomes: evidence for calcium-conducting transmembrane channel formation

Energy Technology Data Exchange (ETDEWEB)

Grasso, P.; Santa-Coloma, T.A.; Reichert, L.E. Jr. (Department of Biochemistry, Albany Medical College, New York, NY (USA))

1991-06-01

We have previously described FSH receptor-mediated influx of 45Ca++ in cultured Sertoli cells from immature rats and receptor-enriched proteoliposomes via activation of voltage-sensitive and voltage-independent calcium channels. We have further shown that this effect of FSH does not require cholera toxin- or pertussis toxin-sensitive guanine nucleotide binding protein or activation of adenylate cyclase. In the present study, we have identified regions of human FSH-beta-subunit which appear to be involved in mediating calcium influx. We screened 11 overlapping peptide amides representing the entire primary structure of hFSH-beta-subunit for their effects on 45Ca++ flux in FSH receptor-enriched proteoliposomes. hFSH-beta-(1-15) and hFSH-beta-(51-65) induced uptake of 45Ca++ in a concentration-related manner. This effect of hFSH-beta-(1-15) and hFSH-beta-(51-65) was also observed in liposomes lacking incorporated FSH receptor. Reducing membrane fluidity by incubating liposomes (containing no receptor) with hFSH-beta-(1-15) or hFSH-beta-(51-65) at temperatures lower than the transition temperatures of their constituent phospholipids resulted in no significant (P greater than 0.05) difference in 45Ca++ uptake. The effectiveness of the calcium ionophore A23187, however, was abolished. Ruthenium red, a voltage-independent calcium channel antagonist, was able to completely block uptake of 45Ca++ induced by hFSH-beta-(1-15) and hFSH-beta-(51-65) whereas nifedipine, a calcium channel blocker specific for L-type voltage-sensitive calcium channels, was without effect. These results suggest that in addition to its effect on voltage-sensitive calcium channel activity, interaction of FSH with its receptor may induce formation of transmembrane aqueous channels which also facilitate influx of extracellular calcium.

Action of luteinizing hormone-releasing hormone in rat ovarian cells: Hormone production and signal transduction

Energy Technology Data Exchange (ETDEWEB)

Wang, Jian.

1989-01-01

The present study was conducted to investigate the hypothesis that the breakdown of membrane phosphoinositides may participate in the actions of luteinizing hormone-releasing hormone (LHRH) on hormone production in rat granulosa cells. In cells prelabeled with ({sup 3}H)inositol or ({sup 3}H)arachidonic acid (AA), treatment with LHRH increased the formation of radiolabeled inositol 1,4,5-trisphosphate (IP{sub 3}) and diacylglycerol (DG), and the release of radiolabeled AA. Since IP{sub 3} induces intracellular Ca{sup 2+} mobilization, changes in the cytosolic free calcium ion concentrations ((Ca{sup 2+})i) induced by LHRH were studied in individual cells using fura-2 microspectrofluorimetry. Alterations in (Ca{sup 2+})i induced by LHRH were rapid and transient, and could be completely blocked by a LHRH antagonist. Sustained perifusion of LHRH resulted in a desensitization of the (Ca{sup 2+})i response to LHRH. LHRH treatment accelerated (Ca{sup 2+})i depletion in the cells perifused with Ca{sup 2+} free medium, indicating the involvement of intracellular Ca{sup 2+} pool(s) in (Ca{sup 2+})i changes. The actions of LHRH on the regulation of progesterone (P{sub 4}) and prostaglandin E{sub 2} (PGE{sub 2}) production were also examined. LHRH increased basal P{sub 4} production and attenuated FSH induced P{sub 4} production. Both basal and FSH stimulated PGE{sub 2} formation were increased by LHRH. Since LHRH also increased the formation of DG that stimulates the activity of protein kinase C, an activator of protein kinase C (12-0-tetradecanolyphorbol-13-acetate: TPA) was used with the Ca{sup 2+} ionophore A23187 and melittin (an activator of phospholipase A{sub 2}) to examine the roles of protein kinase C, Ca{sup 2+} and free AA, respectively, in LHRH action.

Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

International Nuclear Information System (INIS)

Kim, Yong Soo; Lim, Youn Mook; Gwon, Hui Jeong; Choi, Bo Ram; Nho, Young Chang

2009-01-01

Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells

Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Soo; Lim, Youn Mook; Gwon, Hui Jeong; Choi, Bo Ram; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2009-12-15

Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells.

Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells.

Directory of Open Access Journals (Sweden)

Jie Hong

Full Text Available Mechanisms of the progression from Barrett's esophagus (BE to esophageal adenocarcinoma (EA are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA.

The effect of xanthine oxidase and hypoxanthine on the permeability of red cells from patients with sickle cell anemia.

Science.gov (United States)

Al Balushi, Halima W M; Rees, David C; Brewin, John N; Hannemann, Anke; Gibson, John S

2018-03-01

Red cells from patients with sickle cell anemia (SCA) are under greater oxidative challenge than those from normal individuals. We postulated that oxidants generated by xanthine oxidase (XO) and hypoxanthine (HO) contribute to the pathogenesis of SCA through altering solute permeability. Sickling, activities of the main red cell dehydration pathways (P sickle , Gardos channel, and KCl cotransporter [KCC]), and cell volume were measured at 100, 30, and 0 mmHg O 2 , together with deoxygenation-induced nonelectrolyte hemolysis. Unexpectedly, XO/HO mixtures had mainly inhibitory effects on sickling, P sickle , and Gardos channel activities, while KCC activity and nonelectrolyte hemolysis were increased. Gardos channel activity was significantly elevated in red cells pharmacologically loaded with Ca 2+ using the ionophore A23187, consistent with an effect on the transport system per se as well as via Ca 2+ entry likely via the P sickle pathway. KCC activity is controlled by several pairs of conjugate protein kinases and phosphatases. Its activity, however, was also stimulated by XO/HO mixtures in red cells pretreated with N-ethylmaleimide (NEM), which is thought to prevent regulation via changes in protein phosphorylation, suggesting that the oxidants formed could also have direct effects on this transporter. In the presence of XO/HO, red cell volume was better maintained in deoxygenated red cells. Overall, the most notable effect of XO/HO mixtures was an increase in red cell fragility. These findings increase our understanding of the effects of oxidative challenge in SCA patients and are relevant to the behavior of red cells in vivo. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

comparison of a two phase diet with three phase comercial broiler ...

African Journals Online (AJOL)

Nyiko

drinking water; (2) challenged and medicated with a registered ionophore coccidiostat (Salinomycin® in. Trial 1 and ... The coccidiostat treatment group had a significantly lower ..... Nanotechnology in medicine and antibacterial effect of silver ...

Structures and properties of naturally occurring polyether antibiotics.

Science.gov (United States)

Rutkowski, Jacek; Brzezinski, Bogumil

2013-01-01

Polyether ionophores represent a large group of natural, biologically active substances produced by Streptomyces spp. They are lipid soluble and able to transport metal cations across cell membranes. Several of polyether ionophores are widely used as growth promoters in veterinary. Polyether antibiotics show a broad spectrum of bioactivity ranging from antibacterial, antifungal, antiparasitic, antiviral, and tumour cell cytotoxicity. Recently, it has been shown that some of these compounds are able to selectively kill cancer stem cells and multidrug-resistant cancer cells. Thus, they are recognized as new potential anticancer drugs. The biological activity of polyether ionophores is strictly connected with their molecular structure; therefore, the purpose of this paper is to present an overview of their formula, molecular structure, and properties.

Effects of DK-002, a synthesized (6aS,cis)-9,10-Dimethoxy-7,11b-dihydro-indeno[2,1-c]chromene-3,6a-diol, on platelet activity.

Science.gov (United States)

Lee, Ki-Seon; Khil, Lee-Yong; Chae, Sang-Ho; Kim, Deukjoon; Lee, Byung-Hoon; Hwang, Gwi-Seo; Moon, Chang-Hyun; Chang, Tong-Shin; Moon, Chang-Kiu

2006-02-02

In the present study, the mechanism of antiplatelet activity of DK-002, a synthesized (6aS,cis)-9,10-Dimethoxy-7,11b-dihydro-indeno[2,1-c]chromene-3,6a-diol, was investigated. DK-002 inhibited the thrombin, collagen, and ADP-induced rat platelet aggregation in a concentration-dependent manner, with IC50 values of 120, 27, and 47 microM, respectively. DK-002 also inhibited thrombin-induced dense granule secretion, thromboxane A2 synthesis, and [Ca2+]i elevation in platelets. DK-002 did not show any significant effect on ADP-induced inhibition of cyclic AMP elevation by prostaglandin E1, but DK-002 was confirmed to inhibit ADP-induced [Ca2+]i elevation and shape change. DK-002 inhibited 4-bromo-A23187-induced [Ca2+]i elevation in the presence of creatine phosphate/creatine phosphokinase (CP/CPK, a ADP scavenging system) and indomethacin (a specific inhibitor of cyclooxygenase). DK-002 also inhibited Ca2+ mobilization in thrombin- or 4-bromo-A23187-stimulated platelets through its inhibitory effects on both Ca2+ release from intracellular stores and Ca2+ influx, in the presence of CP/CPK and indomethacin. Taken together, the present study shows that DK-002 has inhibitory effects on stimulation of platelets, and suggests that its antiplatelet activity might be related to the inhibitory mechanism on Ca2+ mobilization in stimulated platelets.

Alkali metals and group IIA metals

International Nuclear Information System (INIS)

Fenton, D.E.

1987-01-01

This chapter on the coordination complexes of the alkali metals of group IIA starts with a historical perspective of their chemistry, from simple monodentate ligands, metal-β-diketonates to the macrocyclic polyethers which act as ligands to the alkali and akaline earth metals. Other macrocyclic ligands include quarterenes, calixarenes, porphyrins, phthalocyanines and chlorophylls. A section on the naturally occurring ionophores and carboxylic ionophores is included. (UK)

Cannabinoid inhibition of adenylate cyclase-mediated signal transduction and interleukin 2 (IL-2) expression in the murine T-cell line, EL4.IL-2.

Science.gov (United States)

Condie, R; Herring, A; Koh, W S; Lee, M; Kaminski, N E

1996-05-31

Cannabinoid receptors negatively regulate adenylate cyclase through a pertussis toxin-sensitive GTP-binding protein. In the present studies, signaling via the adenylate cyclase/cAMP pathway was investigated in the murine thymoma-derived T-cell line, EL4.IL-2. Northern analysis of EL4.IL-2 cells identified the presence of 4-kilobase CB2 but not CB1 receptor-subtype mRNA transcripts. Southern analysis of genomic DNA digests for the CB2 receptor demonstrated identical banding patterns for EL4.IL-2 cells and mouse-derived DNA, both of which were dissimilar to DNA isolated from rat. Treatment of EL4.IL-2 cells with either cannabinol or Delta9-THC disrupted the adenylate cyclase signaling cascade by inhibiting forskolin-stimulated cAMP accumulation which consequently led to a decrease in protein kinase A activity and the binding of transcription factors to a CRE consensus sequence. Likewise, an inhibition of phorbol 12-myristate 13-acetate (PMA)/ionomycin-induced interleukin 2 (IL-2) protein secretion, which correlated to decreased IL-2 gene transcription, was induced by both cannabinol and Delta9-THC. Further, cannabinoid treatment also decreased PMA/ionomycin-induced nuclear factor binding to the AP-1 proximal site of the IL-2 promoter. Conversely, forskolin enhanced PMA/ionomycin-induced AP-1 binding. These findings suggest that inhibition of signal transduction via the adenylate cyclase/cAMP pathway induces T-cell dysfunction which leads to a diminution in IL-2 gene transcription.

Piezoresistive microcantilever based lab-on-a-chip system for detection of macronutrients in the soil

Science.gov (United States)

Patkar, Rajul S.; Ashwin, Mamta; Rao, V. Ramgopal

2017-12-01

Monitoring of soil nutrients is very important in precision agriculture. In this paper, we have demonstrated a micro electro mechanical system based lab-on-a-chip system for detection of various soil macronutrients which are available in ionic form K+, NO3-, and H2PO4-. These sensors are highly sensitive piezoresistive silicon microcantilevers coated with a polymer matrix containing methyltridodecylammonium nitrate ionophore/ nitrate ionophore VI for nitrate sensing, 18-crown-6 ether for potassium sensing and Tributyltin chloride for phosphate detection. A complete lab-on-a-chip system integrating a highly sensitive current excited Wheatstone's bridge based portable electronic setup along with arrays of microcantilever devices mounted on a printed circuit board with a liquid flow cell for on the site experimentation for soil test has been demonstrated.

Chromoionophoric Recognition of Alkylamines by Nitro Derivative

International Nuclear Information System (INIS)

Kim, Ju Hee; Hwang, Ah Ran; Choe, Jong In; Chang, Suk Kyu

2004-01-01

The molecular design of efficient and selective chromogenic and fluorogenic ionophore systems for the sensing of chemically and biologically important ionic guests has attracted much attention in the past decade. Many of the compounds are based on the well-known molecular framework of crown ethers, calixarenes, and other EDTA type efficient chelating compounds. Among them the calix[4]arenes are particularly attractive for their selective ionophoric properties toward many of interesting organic ammonium guests. Particularly, the calix[4]arene-crown ethers are known to have unique binding properties toward some of alkali, alkaline earth metal ions, and biogenic amines. Many of the chromogenic sensing materials are developed by conjugating molecular framework of calix[4]- arene-crown ethers with suitable signaling functions of azophenols, thiazoles, and indophenols. Quite unexpectedly, however, the ionophoric properties of simple nitro derivative of calix[4]arene-crown ethers were not reported, except for the closely related structure having ester-ether functions in crown moiety, in spite of their synthetically easy availability and expectedly efficient ionophoric properties toward organic amine guests. In this paper, we report the ionophoric properties of dinitro derivative of calix[4]arene-crown-5 ether 1 toward representative alkylammonium ions aiming for the development of efficient and selective chromogenic sensing material for the biologically important organic amine guests. The Ba 2+ -selective chromogenic behavior of 1 over the representative alkali and alkaline earth metal ions has been reported earlier.

Differential stimulation of luminol-enhanced chemiluminescence (CL) and arachidonic acid metabolism in rat peritoneal neutrophils

Energy Technology Data Exchange (ETDEWEB)

Sturm, R.J.; Adams, L.M.; Cullinan, C.A.; Berkenkopf, J.W.; Weichman, B.M.

1986-03-05

Phorbol 12-myristate, 13-acetate (PMA) induced the production of radical oxygen species (ROS) from rat peritoneal neutrophils as assessed by CL. ROS generation occurred in a time- (maximum at 13.5 min) and dose- (concentration range of 1.7-498 nM) related fashion. However, 166 nM PMA did not induce either cyclooxygenase (CO) or lipoxygenase (LPO) product formation by 20 min post-stimulation. Conversely, A23187, at concentrations between 0.1 and 10 ..mu..M, stimulated both pathways of arachidonic acid metabolism, but had little or no effect upon ROS production. When suboptimal concentrations of PMA (5.5 nM) and A23187 (0.1-1 ..mu..M) were coincubated with the neutrophils, a synergistic ROS response was elicited. However, arachidonic acid metabolism in the presence of PMA was unchanged relative to A12187 alone. Nordihydroguaiaretic acid (NDGA) inhibited both PMA-induced CL (IC/sub 50/ = 0.9 ..mu..M) and A23187-induced arachidonic acid metabolism (IC/sub 50/ = 1.7 ..mu..M and 6.0 ..mu..M for LPO and CO, respectively). The mixed LPO-CO inhibitor, BW755C, behaved in a qualitatively similar manner to NDGA, whereas the CO inhibitors, indomethacin, piroxicam and naproxen had no inhibitory effect on ROS generation at concentrations as high as 100 ..mu..M. These results suggest that NDGA and BW755C may inhibit CL and arachidonic acid metabolism by distinct mechanisms in rat neutrophils.

Hops (Humulus lupulus L. Bitter Acids: Modulation of Rumen Fermentation and Potential As an Alternative Growth Promoter

Directory of Open Access Journals (Sweden)

Michael D. Flythe

2017-08-01

Full Text Available Antibiotics can improve ruminant growth and efficiency by altering rumen fermentation via selective inhibition of microorganisms. However, antibiotic use is increasingly restricted due to concerns about the spread of antibiotic-resistance. Plant-based antimicrobials are alternatives to antibiotics in animal production. The hops plant (Humulus lupulus L. produces a range of bioactive secondary metabolites, including antimicrobial prenylated phloroglucinols, which are commonly called alpha- and beta-acids. These latter compounds can be considered phyto-ionophores, phytochemicals with a similar antimicrobial mechanism of action to ionophore antibiotics (e.g., monensin, lasalocid. Like ionophores, the hop beta-acids inhibit rumen bacteria possessing a classical Gram-positive cell envelope. This selective inhibition causes several effects on rumen fermentation that are beneficial to finishing cattle, such as decreased proteolysis, ammonia production, acetate: propionate ratio, and methane production. This article reviews the effects of hops and hop secondary metabolites on rumen fermentation, including the physiological mechanisms on specific rumen microorganisms, and consequences for the ruminant host and ruminant production. Further, we propose that hop beta-acids are useful model natural products for ruminants because of (1 the ionophore-like mechanism of action and spectrum of activity and (2 the literature available on the plant due to its use in brewing.

Binding of thrombin-activated platelets to a fibrin scaffold through α(IIb)β₃ evokes phosphatidylserine exposure on their cell surface.

Science.gov (United States)

Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei

2013-01-01

Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an α(IIb)β₃ antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment.

Effect of breed type and ionophore supplementation on growth and carcass characteristic in feedlot hair lambs Efeito do grupo genético e da suplementação com ionóforos sobre o crescimento e as características de carcaça de cordeiros deslanados confinados

Directory of Open Access Journals (Sweden)

Jaime Salinas-Chavira

2010-03-01

Full Text Available The effects of supplementing feedlot diets with ionophores and breed type were assessed on growth rate and carcass characteristics in hair lambs. Twenty four intact males, 12 Pelibuey × Dorper (PDo and 12 Pelibuey × Damara (PDa lambs, 17.9 ± 3.7 kg initial weight, were housed in individual pens for a 60-d feeding trial. The lambs were assigned randomly into four diets: control without additives (C; 25 µg/g monensin (M; 28 µg/g salinomycin (S; 28 µg/g S for 20 d, and 25 µg/g M for the next 40 d (SM. Each diet was supplied to six lambs. Data were analyzed as a randomized complete block design in a 4 × 2 factorial arrangement, with four diets and two breed types of hair lambs (PDo and PDa. All diets were formulated to contain 14% CP and 2.6 Mcal ME/kg dry matter. At the end of the feeding trial carcass images were recorded in the last intercostal space (12th and 13th ribs using ultrasound equipment to measure the Longissimus dorsi muscle area and subcutaneous fat (SF. The average daily gain (ADG, daily dry matter intake, feed:gain ratio, subcutaneous fat and Longissimus dorsi area were not affected by ionophore supplementation.. The Pelibuey × Dorper group tended to show better average daily gain than Pelibuey × Damara (262 g/d and 235 g/d, respectively. Daily dry matter intake, feed:gain ratio and subcutaneous fat were not affected by breed type. The Pelibuey × Dorper lambs had greater Longissimus dorsi area (16.74 cm² than the Pelibuey × Damara (14.29 cm² lambs. The growth rate was not influenced by the inclusion of ionophores. Pelibuey × Dorper lambs showed better average daily gain and carcass characteristics than Pelibuey × Damara lambs.Avaliaram-se os efeitos da suplementação de dietas de confinamento com ionóforos e da raça do animal na taxa de crescimento e nas características de carcaça de cordeiros deslanados. Vinte e quatro machos não-castrados – 12 cordeiros Pelibuey × Dorper (PDo e 12 cordeiros Pelibuey �

Studies on the matched potential method for determining the selectivity coefficients of ion-selective electrodes based on neutral ionophores: experimental and theoretical verification.

Science.gov (United States)

Tohda, K; Dragoe, D; Shibata, M; Umezawa, Y

2001-06-01

A theory is presented that describes the matched potential method (MPM) for the determination of the potentiometric selectivity coefficients (KA,Bpot) of ion-selective electrodes for two ions with any charge. This MPM theory is based on electrical diffuse layers on both the membrane and the aqueous side of the interface, and is therefore independent of the Nicolsky-Eisenman equation. Instead, the Poisson equation is used and a Boltzmann distribution is assumed with respect to all charged species, including primary, interfering and background electrolyte ions located at the diffuse double layers. In this model, the MPM-selectivity coefficients of ions with equal charge (ZA = ZB) are expressed as the ratio of the concentrations of the primary and interfering ions in aqueous solutions at which the same amounts of the primary and interfering ions permselectively extracted into the membrane surface. For ions with unequal charge (ZA not equal to ZB), the selectivity coefficients are expressed as a function not only of the amounts of the primary and interfering ions permeated into the membrane surface, but also of the primary ion concentration in the initial reference solution and the delta EMF value. Using the measured complexation stability constants and single ion distribution coefficients for the relevant systems, the corresponding MPM selectivity coefficients can be calculated from the developed MPM theory. It was found that this MPM theory is capable of accurately and precisely predicting the MPM selectivity coefficients for a series of ion-selective electrodes (ISEs) with representative ionophore systems, which are generally in complete agreement with independently determined MPM selectivity values from the potentiometric measurements. These results also conclude that the assumption for the Boltzmann distribution was in fact valid in the theory. The recent critical papers on MPM have pointed out that because the MPM selectivity coefficients are highly concentration

The Acid Test: Calcium Signaling in the Skeletogenic Layer of Reef-Building Coral

Science.gov (United States)

Florn, A. M.

2016-02-01

Since the Industrial Revolution, carbon dioxide (CO2) emissions have increased more than 40%. This increased atmospheric CO2 drives ocean acidification and has potentially serious consequences for all marine life, especially calcifying organisms. The specific goal of this study was to examine calcium homeostasis and signaling dynamics within the skeletogenic tissue layers (calicodermal cells) of two coral species (Pavona maldivensis and Porites rus) at three pH treatments corresponding to present-future ocean acidification levels. Confocal microscopy techniques were used to analyze in vivo calcium dynamics of the calicodermal cells in Pavona maldivensis and Porites rus. The results show biological variation between the two reef-building coral species and their response to ocean acidification. Pavona maldivensis showed a significant difference (p < 0.01) in the ionomycin-induced calcium response among the pH treatments, but not among the microcolonies. Porites rus did not show a significant difference (p < 0.01) in the ionomycin-induced calcium response among the pH treatments or the microcolonies. Upon comparing the calcium response curves, the ionomycin-induced calcium response exhibited by Pavona maldivensis is phenomenologically similar to a calcium response that is commonly found in vertebrates. This well-studied phenomenon in vertebrate biology is known as store-operated calcium entry (SOCE) and is closely associated with the endoplasmic reticulum (ER) and mitochondria-associated endoplasmic reticulum (MAM) calcium stores. This study provides insight into the preliminary steps needed to understand in vivo calcium signaling in the calicodermis of reef-building coral and the associated consequences of ocean acidification.

Study on cytokine modulation in mast cell-induced allergic reactions by using gamma-irradiated natural herbal extracts

International Nuclear Information System (INIS)

Gwon, Hui Jeong; Lim, Youn Mook; Kim, Yong Soo; Nho, Young Chang; Kim Hae Kyoung

2009-01-01

We previously described that some natural herbal extracts such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U), differentially suppress an atopic dermatitis like skin lesions. The objective of this study was to evaluate the pro-inflammatory cytokine modulation of the water extract of the H, C, P, M, U, and those mixtures (M) and their mechanism in a phorbol myristate acetate (PMA) plus calcium inopore A23187 treated human mast cell line (HMC-1). The H, C, P, M, U, and M inhibited the inflammatory cytokines such as TNF-α, IL-6 and IL-8 stimulated by PMA plus A23187 from HMC-1 cells. In addition, the M did not significantly affect the cell viability and had no toxicity on the HMC-1 cells. Based on these results, M can be used for the treatment of an allergic inflammation response

Study on cytokine modulation in mast cell-induced allergic reactions by using gamma-irradiated natural herbal extracts

Energy Technology Data Exchange (ETDEWEB)

Gwon, Hui Jeong; Lim, Youn Mook; Kim, Yong Soo; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kim Hae Kyoung [Chonbuk National University, Jeonju (Korea, Republic of)

2009-12-15

We previously described that some natural herbal extracts such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U), differentially suppress an atopic dermatitis like skin lesions. The objective of this study was to evaluate the pro-inflammatory cytokine modulation of the water extract of the H, C, P, M, U, and those mixtures (M) and their mechanism in a phorbol myristate acetate (PMA) plus calcium inopore A23187 treated human mast cell line (HMC-1). The H, C, P, M, U, and M inhibited the inflammatory cytokines such as TNF-{alpha}, IL-6 and IL-8 stimulated by PMA plus A23187 from HMC-1 cells. In addition, the M did not significantly affect the cell viability and had no toxicity on the HMC-1 cells. Based on these results, M can be used for the treatment of an allergic inflammation response.

Low-dose gamma-rays and simulated solar particle event protons modify splenocyte gene and cytokine expression patterns

International Nuclear Information System (INIS)

Rizvi, A.; Pecaut, M.J.; Gridley, D.S.

2011-01-01

The goal was to investigate the T helper (Th) response in splenocytes of mice exposed to low-dose/low-dose-rate (LDR) γ-rays, simulated solar particle event protons (sSPE), or combination of both. C57BL/6 mice were exposed to LDR γ-radiation ( 57 Co) to a total dose of 0.05 Gray (Gy) at 0.024 cGy/h, either with or without subsequent exposure to 2 Gy sSPE protons. Expression of genes related to Th cells was evaluated immediately after exposure (day 0). On day 21, intra- and extracellular cytokine production was assessed after activation with anti-CD3 monoclonal antibodies (mAb) or phorbol 12-myristate 13-acetate/ionophore (PMA/I). Five genes were significantly modulated on day 0 in one or more of the irradiated groups compared to controls (p<0.05): Ccl11, Ccr5, Cd80, Inha, and Il9. On day 21, numbers of cells positive for interferon-γ were high in the LDR + sSPE group versus 0 Gy and LDR γ-rays (p<0.05), but there was no difference in interleukin (IL)-2 and tumor necrosis factor (TNF)-α. Levels of secreted cytokines after anti-CD3 mAb activation were high for 5 (maximum intensity projection (MIP)-1α, GM-CSF, interferon (IFN)-γ, TNF-α, IL-13) and low for 2 (IL-7, IL-9) in all irradiated groups. Priming with LDR photons had a significant effect on IFN-γ and IL-17 compared to sSPE protons alone; IL-2 was low only in the LDR + sSPE group. The cytokine patterns after anti-phorbol myristate acetate (PMA)/ionomycin (I) activation were different compared to anti-CD3 mAb and with fewer differences among groups. The data show that total-body exposure to space-relevant radiation has profound effects on Th cell status and that priming with LDR γ-rays can in some cases modulate the response to sSPE. (author)

Regulation of myosin light chain kinase during insulin-stimulated glucose uptake in 3T3-L1 adipocytes.

Directory of Open Access Journals (Sweden)

Shelly Woody

Full Text Available Myosin II (MyoII is required for insulin-responsive glucose transporter 4 (GLUT4-mediated glucose uptake in 3T3-L1 adipocytes. Our previous studies have shown that insulin signaling stimulates phosphorylation of the regulatory light chain (RLC of MyoIIA via myosin light chain kinase (MLCK. The experiments described here delineate upstream regulators of MLCK during insulin-stimulated glucose uptake. Since 3T3-L1 adipocytes express two MyoII isoforms, we wanted to determine which isoform was required for insulin-stimulated glucose uptake. Using a siRNA approach, we demonstrate that a 60% decrease in MyoIIA protein expression resulted in a 40% inhibition of insulin-stimulated glucose uptake. We also show that insulin signaling stimulates the phosphorylation of MLCK. We further show that MLCK can be activated by calcium as well as signaling pathways. We demonstrate that adipocytes treated with the calcium chelating agent, 1,2-b (iso-aminophenoxy ethane-N,N,N',N'-tetra acetic acid, (BAPTA (in the presence of insulin impaired the insulin-induced phosphorylation of MLCK by 52% and the RLC of MyoIIA by 45% as well as impairing the recruitment of MyoIIA to the plasma membrane when compared to cells treated with insulin alone. We further show that the calcium ionophore, A23187 alone stimulated the phosphorylation of MLCK and the RLC associated with MyoIIA to the same extent as insulin. To identify signaling pathways that might regulate MLCK, we examined ERK and CaMKII. Inhibition of ERK2 impaired phosphorylation of MLCK and insulin-stimulated glucose uptake. In contrast, while inhibition of CaMKII did inhibit phosphorylation of the RLC associated with MyoIIA, inhibition of CAMKIIδ did not impair MLCK phosphorylation or translocation to the plasma membrane or glucose uptake. Collectively, our results are the first to delineate a role for calcium and ERK in the activation of MLCK and thus MyoIIA during insulin-stimulated glucose uptake in 3T3-L1 adipocytes.

Mycoplasma orale infection affects K+ and Cl- currents in the HSG salivary gland cell line.

Science.gov (United States)

Izutsu, K T; Fatherazi, S; Belton, C M; Oda, D; Cartwright, F D; Kenny, G E

1996-06-01

The relations between K+ channel and Cl- channel currents and mycoplasma infection status were studied longitudinally in HSG cells, a human submandibular gland cell line. The K+ channel currents were disrupted by the occurrence of mycoplasma infection: muscarinic activation of K+ channels and K+ channel expression as estimated by ionomycin- or hypotonically induced K+ current responses were all decreased. Similar decreases in ionomycin- and hypotonically induced responses were observed for Cl- channels, but only the latter decrease was statistically significant. Also, Cl- currents could be elicited more frequently than K+ currents (63% of cases versus 0%) in infected cells when tested by exposure to hypotonic media, indicating that mycoplasma infection affects K+ channels relatively more than Cl- channels. These changes occurred in the originally infected cells, were ameliorated when the infection was cleared with sparfloxacin, and recurred when the cells were reinfected. Such changes would be expected to result in hyposecretion of salivary fluid if they occurred in vivo.

Binding of Thrombin-Activated Platelets to a Fibrin Scaffold through αIIbβ3 Evokes Phosphatidylserine Exposure on Their Cell Surface

Science.gov (United States)

Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei

2013-01-01

Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an αIIbβ3 antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment. PMID:23383331

Binding of thrombin-activated platelets to a fibrin scaffold through α(IIbβ₃ evokes phosphatidylserine exposure on their cell surface.

Directory of Open Access Journals (Sweden)

Tomasz Brzoska

Full Text Available Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an α(IIbβ₃ antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment.

Calreticulin reveals a critical Ca2+ checkpoint in cardiac myofibrillogenesis

Science.gov (United States)

Li, Jian; Pucéat, Michel; Perez-Terzic, Carmen; Mery, Annabelle; Nakamura, Kimitoshi; Michalak, Marek; Krause, Karl-Heinz; Jaconi, Marisa E.

2002-01-01

Calreticulin (crt) is an ubiquitously expressed and multifunctional Ca2+-binding protein that regulates diverse vital cell functions, including Ca2+ storage in the ER and protein folding. Calreticulin deficiency in mice is lethal in utero due to defects in heart development and function. Herein, we used crt − / − embryonic stem (ES) cells differentiated in vitro into cardiac cells to investigate the molecular mechanisms underlying heart failure of knockout embryos. After 8 d of differentiation, beating areas were prominent in ES-derived wild-type (wt) embryoid bodies (EBs), but not in ES-derived crt − / − EBs, despite normal expression levels of cardiac transcription factors. Crt − / − EBs exhibited a severe decrease in expression and a lack of phosphorylation of ventricular myosin light chain 2 (MLC2v), resulting in an impaired organization of myofibrils. Crt − / − phenotype could be recreated in wt cells by chelating extracellular or cytoplasmic Ca2+ with EGTA or BAPTA, or by inhibiting Ca2+/calmodulin-dependent kinases (CaMKs). An imposed ionomycin-triggered cystolic-free Ca2+ concentration ([Ca2+]c) elevation restored the expression, phosphorylation, and insertion of MLC2v into sarcomeric structures and in turn the myofibrillogenesis. The transcription factor myocyte enhancer factor C2 failed to accumulate into nuclei of crt − / − cardiac cells in the absence of ionomycin-triggered [Ca2+]c increase. We conclude that the absence of calreticulin interferes with myofibril formation. Most importantly, calreticulin deficiency revealed the importance of a Ca2+-dependent checkpoint critical for early events during cardiac myofibrillogenesis. PMID:12105184

Fluorinated tripodal receptors for potentiometric chloride detection in biological fluids.

Science.gov (United States)

Pankratova, Nadezda; Cuartero, Maria; Jowett, Laura A; Howe, Ethan N W; Gale, Philip A; Bakker, Eric; Crespo, Gastón A

2018-01-15

Fluorinated tripodal compounds were recently reported to be efficient transmembrane transporters for a series of inorganic anions. In particular, this class of receptors has been shown to be suitable for the effective complexation of chloride, nitrate, bicarbonate and sulfate anions via hydrogen bonding. The potentiometric properties of urea and thiourea-based fluorinated tripodal receptors are explored here for the first time, in light of the need for reliable sensors for chloride monitoring in undiluted biological fluids. The ion selective electrode (ISE) membranes with tren-based tris-urea bis(CF 3 ) tripodal compound (ionophore I) were found to exhibit the best selectivity for chloride over major lipophilic anions such as salicylate ( [Formula: see text] ) and thiocyanate ( [Formula: see text] ). Ionophore I-based ISEs were successfully applied for chloride determination in undiluted human serum as well as artificial serum sample, the slope of the linear calibration at the relevant background of interfering ions being close to Nernstian (49.8±1.7mV). The results of potentiometric measurements were confirmed by argentometric titration. Moreover, the ionophore I-based ISE membrane was shown to exhibit a very good long-term stability of potentiometric performance over the period of 10 weeks. Nuclear magnetic resonance (NMR) titrations, potentiometric sandwich membrane experiments and density functional theory (DFT) computational studies were performed to determine the binding constants and suggest 1:1 complexation stoichiometry for the ionophore I with chloride as well as salicylate. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of Distinct Roles of CaMKK Isoforms Using STO-609-Resistant Mutants in Living Cells.

Science.gov (United States)

Fujiwara, Yuya; Hiraoka, Yuri; Fujimoto, Tomohito; Kanayama, Naoki; Magari, Masaki; Tokumitsu, Hiroshi

2015-06-30

To assess the isoform specificity of the Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK)-mediated signaling pathway using a CaMKK inhibitor (STO-609) in living cells, we have established A549 cell lines expressing STO-609-resistant mutants of CaMKK isoforms. Following serial mutagenesis studies, we have succeeded in obtaining an STO-609-resistant CaMKKα mutant (Ala292Thr/Leu233Phe) and a CaMKKβ mutant (Ala328Thr/Val269Phe), which showed sensitivity to STO-609 that was 2-3 orders of magnitude lower without an appreciable effect on kinase activity or CaM requirement. These results are consistent with the results obtained for CaMKK activities in the extracts of A549 cells stably expressing the mutants of CaMKK isoforms. Ionomycin-induced 5'-AMP-activated protein kinase (AMPK) phosphorylation at Thr172 in A549 cells expressing either the wild-type or the STO-609-resistant mutant of CaMKKα was completely suppressed by STO-609 treatment but resistant to the inhibitor in the presence of the CaMKKβ mutant (Ala328Thr/Val269Phe). This result strongly suggested that CaMKKβ is responsible for ionomycin-induced AMPK activation, which supported previous reports. In contrast, ionomycin-induced CaMKIV phosphorylation at Thr196 was resistant to STO-609 treatment in A549 cells expressing STO-609-resistant mutants of both CaMKK isoforms, indicating that both CaMKK isoforms are capable of phosphorylating and activating CaMKIV in living cells. Considering these results together, STO-609-resistant CaMKK mutants developed in this study may be useful for distinguishing CaMKK isoform-mediated signaling pathways in combination with the use of an inhibitor compound.

Poly (Vinyl Chloride Based Ion Selective Electrode for Determination of Zr (IV Ions Based on 2, 6-Dibenzylidenecyclohexanone

Directory of Open Access Journals (Sweden)

Syed A. Nabi

2008-08-01

Full Text Available A selective poly (vinyl chloride-based membrane sensor using 2,6-Dibenzylidenecyclohexanone as an ionophore have been prepared and explored as Zr (IV selective electrode. The sensitivity, working range and response time shows a significant dependence on the concentration of ionophore. The electrode prepared with 100 mg of PVC, 10 mg of ionophore and 5 ml of dibutylthylate shows the best performance. The electrode works well in the concentration range of 1×10-1-5×10-5 with a nerstian slope 55±2 eV and response time of 18 seconds. The sensor works well over the pH range 3-6. The sensor can be used for the period of over 1 month with out deviation in response characteristics. The selectivity of the electrode was studied and it was found that the electrode exhibited good selectivity for zirconium (IV over some alkaline earth metal ions. The electrode was also used as indicator electrode for potentiometeric titration of Zr (IV ions against EDTA solution.

Bacteria-induced histamine release from human bronchoalveolar cells and blood leukocytes

DEFF Research Database (Denmark)

Clementsen, P; Milman, N; Struve-Christensen, E

1991-01-01

23187 resulted in histamine release. S. aureus-induced histamine release from basophils was examined in leukocyte suspensions obtained from the same individuals, and in all experiments release was found. The dose-response curves were similar to those obtained with BAL cells. The bacteria...

Synthetic tambjamine analogues induce mitochondrial swelling and lysosomal dysfunction leading to autophagy blockade and necrotic cell death in lung cancer.

Science.gov (United States)

Rodilla, Ananda M; Korrodi-Gregório, Luís; Hernando, Elsa; Manuel-Manresa, Pilar; Quesada, Roberto; Pérez-Tomás, Ricardo; Soto-Cerrato, Vanessa

2017-02-15

Current pharmacological treatments for lung cancer show very poor clinical outcomes, therefore, the development of novel anticancer agents with innovative mechanisms of action is urgently needed. Cancer cells have a reversed pH gradient compared to normal cells, which favours cancer progression by promoting proliferation, metabolic adaptation and evasion of apoptosis. In this regard, the use of ionophores to modulate intracellular pH appears as a promising new therapeutic strategy. Indeed, there is a growing body of evidence supporting ionophores as novel antitumour drugs. Despite this, little is known about the implications of pH deregulation and homeostasis imbalance triggered by ionophores at the cellular level. In this work, we deeply analyse for the first time the anticancer effects of tambjamine analogues, a group of highly effective anion selective ionophores, at the cellular and molecular levels. First, their effects on cell viability were determined in several lung cancer cell lines and patient-derived cancer stem cells, demonstrating their potent cytotoxic effects. Then, we have characterized the induced lysosomal deacidification, as well as, the massive cytoplasmic vacuolization observed after treatment with these compounds, which is consistent with mitochondrial swelling. Finally, the activation of several proteins involved in stress response, autophagy and apoptosis was also detected, although they were not significantly responsible for the cell death induced. Altogether, these evidences suggest that tambjamine analogues provoke an imbalance in cellular ion homeostasis that triggers mitochondrial dysfunction and lysosomal deacidification leading to a potent cytotoxic effect through necrosis in lung cancer cell lines and cancer stem cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Possibilities and limitations of the sequential injection chromatography technique for the determination of anticoccidial agents in water, pharmaceutical formulations and feed

DEFF Research Database (Denmark)

Bjørklund, E.; Maya, Fernando; Bak, S A

2011-01-01

... hyphenated with sensitive mass spectrometry have been employed for analysis of ionophores in various water bodies as recently summarized by Hansen and coworkers [9]. On the contrary, the synthetic chemicals have not been monitored in the environment before, while other ...... hyphenated with sensitive mass spectrometry have been employed for analysis of ionophores in various water bodies as recently summarized by Hansen and coworkers [9]. On the contrary, the synthetic chemicals have not been monitored in the environment before, while other ...

Hydroxychloroquine inhibits CD154 expression in CD4+ T lymphocytes of systemic lupus erythematosus through NFAT, but not STAT5, signaling.

Science.gov (United States)

Wu, Shu-Fen; Chang, Chia-Bin; Hsu, Jui-Mei; Lu, Ming-Chi; Lai, Ning-Sheng; Li, Chin; Tung, Chien-Hsueh

2017-08-09

Overexpression of membranous CD154 in T lymphocytes has been found previously in systemic lupus erythematosus (SLE). Because hydroxychloroquine (HCQ) has been used frequently in the treatment of lupus, we sought to identify the effects of HCQ on CD154 and a possibly regulatory mechanism. CD4 + T cells were isolated from the blood of lupus patients. After stimulation with ionomycin or IL-15 and various concentrations of HCQ, expression of membranous CD154 and NFAT and STAT5 signaling were assessed. HCQ treatment had significant dose-dependent suppressive effects on membranous CD154 expression in ionomycin-activated T cells from lupus patients. Furthermore, HCQ inhibited intracellular sustained calcium storage release, and attenuated the nuclear translocation of NFATc2 and the expression of NFATc1. However, CD154 expressed through IL-15-mediated STAT5 signaling was not inhibited by HCQ treatment. HCQ inhibited NFAT signaling in activated T cells and blocked the expression of membranous CD154, but not STAT5 signaling. These findings provide a mechanistic insight into SLE in HCQ treatment.

A novel EIS field effect structures coated with TESUD-PPy-PVC-dibromoaza[7]helicene matrix for potassium ions detection

Energy Technology Data Exchange (ETDEWEB)

Tounsi, Moncef, E-mail: tounsi1981@live.fr [Laboratoire des Interfaces et des Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Université de Monastir (Tunisia); Université de Lyon, Institut de Sciences Analytiques (ISA) – UMR 5280, 5 rue de la Doua, 69100 Villeurbanne (France); Ben Braiek, Mourad [Laboratoire de Synthèse Organique Asymétrique et Catalyse Homogène, Faculté des Sciences, Université de Monastir, Avenue de l' environnement, 5019, Monastir (Tunisia); Barhoumi, Houcine [Laboratoire des Interfaces et des Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Université de Monastir (Tunisia); Baraket, Abdoullatif; Lee, Michael; Zine, Nadia [Université de Lyon, Institut de Sciences Analytiques (ISA) – UMR 5280, 5 rue de la Doua, 69100 Villeurbanne (France); Maaref, Abderrazak [Laboratoire des Interfaces et des Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Université de Monastir (Tunisia); Errachid, Abdelhamid, E-mail: abdelhamid.errachid-el-salhi@univ-lyon1.fr [Université de Lyon, Institut de Sciences Analytiques (ISA) – UMR 5280, 5 rue de la Doua, 69100 Villeurbanne (France)

2016-04-01

In this work, we describe the development of new Aza[7]helicene-containing PVC-based membranes for the K{sup +} ions quantification. Here, silicon nitride-based structures (Si-p/SiO{sub 2}/Si{sub 3}N{sub 4}) were developed and the surface was activated, functionalized with an aldehyde–silane (11-(Triethoxysilyl)undecanal (TESUD)), functionalized with polypyrrole (PPy), and coated with the polyvinylchloride (PVC)-membrane containing the Aza[7]helicene as ionophore. All stages of functionalization process have been thoroughly studied by contact angle measurements (CAMs) and atomic force microscopy (AFM). The developed ion-selective electrode (ISE) was then applied using electrochemical impedance spectroscopy (EIS) for the detection of potassium ions. A linear range was observed between 1.0 × 10{sup −8} M to 1.0 × 10{sup −3} M and a detection limit of 1.0 × 10{sup −8} M was observed. The EIS results have showed a good sensitivity to potassium ion using this novel technique. The target helicene exhibited good solubility and excellent thermal stability with a high decomposition temperature (Td > 300 °C) and it indicates that helicene may be a promising material as ionophore for ion-selective electrodes (ISEs) elaboration. - Highlights: • Synthesis and characterization of a new derivatives of Aza[7]helicenes • Manufacture of PPy structures on the SiO{sub 2}/Si{sub 3}N{sub 4} surface using the TESUD as cross linking agent. • The PPy fabricated microstructures can be used as support matrix in biosensing. • Impedimetric K{sup +}-ISEs was developed by using dibromoaza[7]helicene as ionophore for K{sup +} ions determination.

Inositol trisphosphate and thapsigargin discriminate endoplasmic reticulum stores of calcium in rat brain

DEFF Research Database (Denmark)

Verma, A; Hirsch, D J; Hanley, M R

1990-01-01

ATP dependent Ca2+ accumulation into oxalate-loaded rat brain microsomes is potently inhibited by thapsigargin with an IC50 of 2 nM and maximal inhibition at 10 nM. Approximately 15% of the total A23187-releasable microsomal calcium store is insensitive to thapsigargin concentrations up to 100 mi...

A steady-state mechanism can account for the properties of inositol 2,4,5-trisphosphate-stimulated Ca2+ release from permeabilized L1210 cells.

Science.gov (United States)

Loomis-Husselbee, J W; Dawson, A P

1993-01-01

We have investigated the effects of sub-maximal Ins(2,4,5)P3 concentrations on the Ca2+ permeability of the residual undischarged Ca2+ stores in electroporated or digitonin-permeabilized L1210 cells by measuring Ca(2+)-efflux rate after addition of the ATPase inhibitor thapsigargin. Low concentrations of Ins(2,4,5)P3, causing rapid discharge of a small proportion of the releasable Ca2+, result in a substantial stimulation of Ca2+ efflux after thapsigargin addition. This indicates firstly that in the absence of thapsigargin there must have been a substantial, counterbalancing, increase in rate of Ca2+ pumping, and secondly that the increased Ca2+ permeability is more consistent with a steady state than with a quantal model of Ca2+ release. Similar increases in passive Ca2+ permeability are produced by addition of concentrations of ionomycin which produce equivalent changes in Ca2+ loading to those produced by Ins(2,4,5)P3, although the time course and initial rate of Ca2+ release are very much slower. In the presence of a Ca(2+)-buffering system, the time course of Ca2+ release by Ins(2,4,5)P3 becomes superimposable on that of ionomycin, indicating that the initial rapid phase of Ins(2,4,5)P3-stimulated Ca2+ is at least partially due to positive feedback from extravesicular Ca2+. PMID:8382056

Arachidonic acid assimilation by thrombocytes from white carneau pigeons

International Nuclear Information System (INIS)

Saxon, D.J.; Blankenship, T.

1986-01-01

The metabolism of arachidonic acid was investigated using thrombocyte-enriched-plasma from RBWC and WC-II white carneau pigeons, which differ genetically in their susceptibility to atherosclerosis. Thrombocytes were incubated at 42 C with [ 14 C] arachidonate in Puck's solution. After a 1 hour labeling period the WC-II cells had taken up 69% and RBWC 77% of the [ 14 C]arachidonate from the medium. When 8,11,14-eicosatrienoic acid or 5,8,11,14,17-eicosapentaenoic acid were added to incubation media the [ 14 C] uptake was reduced in each type cell, with WC-II exhibiting the greatest effect. Release of [ 14 C]molecules from cells labeled with [ 14 ]Carachidonate was studied using calcium ionophore and indomethacin. Indomethacin inhibited [ 14 C] molecule release similarly in both RBWC and WC-II cells. Calcium ionophore was twice as effective in stimulating [ 14 C]molecule release from WC-II than RBWC cells. Therefore, the WE-II cells (from pigeons greater in susceptibility to atherosclerosis) are more sensitive to calcium ionophore than the REWC cells

Rapid changes in protein phosphorylation associated with gravity perception in corn roots

International Nuclear Information System (INIS)

McFadden, J.J.; Poovaiah, B.W.

1987-01-01

A previous paper from this laboratory showed calcium- and calmodulin-dependent in vivo protein phosphorylation in corn root tips. The authors show that rapid changes in calcium-dependent protein phosphorylation are involved in light-dependent graviperception in corn root tips. Corn seedlings (Zea mays L, cv Merit) were grown in the dark for 3 d, then apical root segments were harvested in dim green light to measure in vivo protein phosphorylation. Segments were incubated with 0.5 mCi 32 P for 1 h, then immediately frozen in liquid N 2 or first treated with either 7 min light, or 7 min light plus 1 mM EGTA and 10 μM A23187. Labeled proteins were separated by 2D gel electrophoresis and detected by autoradiography. Light caused rapid and specific promotion of phosphorylation of 5 polypeptides. The increases in protein phosphorylation were reversed by treating with EGTA and A23187. The authors postulate that these changes in protein phosphorylation are an essential part of the light-dependent gravity response in Merit roots

Increases in cellular calcium concentration stimulate pepsinogen secretion from dispersed chief cells

International Nuclear Information System (INIS)

Raufman, J.P.; Berger, S.; Cosowsky, L.; Straus, E.

1986-01-01

Intracellular calcium concentration ([Ca]i) and pepsinogen secretion from dispersed chief cells from guinea pig stomach were determined before and after stimulation with calcium ionophores. [Ca]i was measured using the fluorescent probe quin2. Basal [Ca]i was 105 +/- 4 nM. Pepsinogen secretion was measured with a new assay using 125 I-albumin substrate. This assay is 1000-fold more sensitive than the widely-used spectrophotometric assay, technically easy to perform, rapid, and relatively inexpensive. The kinetics and stoichiometry of ionophore-induced changes in [Ca]i and pepsinogen secretion were similar. These data support a role for calcium as a cellular mediator of pepsinogen secretion

Involvement of cyclic nucleotides in locust flight muscle metabolism

NARCIS (Netherlands)

Worm, R.A.A.

1980-01-01

1. Flight had no significant effect on the levels of c-AMP of c-GMP in the flight muscles of Locusta migratoria. 2. Injections of 0.01 or 0.1 corpus cardiacum equivalents into the abdominal cavity did not elicit any effect on cyclic nucleotide levels either. 3. Injection of A23187 resulted in

Oxidative metabolism of monensin in rat liver microsomes and interactions with tiamulin and other chemotherapeutic agents: evidence for the involvement of cytochrome P-450 3A subfamily.

Science.gov (United States)

Nebbia, C; Ceppa, L; Dacasto, M; Carletti, M; Nachtmann, C

1999-09-01

Monensin (MON) is an ionophore antibiotic widely used in veterinary practice as a coccidiostatic or a growth promoter. The aims of this study were to characterize the P-450 isoenzyme(s) involved in the biotransformation of the ionophore and to investigate how this process may be affected by tiamulin and other chemotherapeutic agents known to produce toxic interactions with MON when administered concurrently in vivo. In liver microsomes from untreated rats (UT) or from rats pretreated, respectively, with ethanol (ETOH), beta-naphthoflavone (betaNAF), phenobarbital (PB), pregnenolone 16alpha-carbonitrile (PCN), or dexamethasone (DEX), the rate of MON O-demethylation was the following: DEX > PCN > PB > UT = ETOH > betaNAF; similar results were obtained by measuring total MON metabolism. In addition, the extent of triacetyloleandomycin-mediated P-450 complexes was greatly reduced by the prior addition of 100 microM MON. In DEX-treated microsomes, MON O-demethylation was found to fit monophasic Michaelis-Menten kinetics (K(M) = 67.6 +/- 0.01 microM; V(max) = 4.75 +/- 0.76 nmol/min/mg protein). Tiamulin markedly inhibited this activity in an apparent competitive manner, with a calculated K(i) (Dixon plot) of 8.2 microM and an IC(50) of about 25 microM. At the latter concentration, only ketoconazole or metyrapone, which can bind P-450 3A, inhibited MON O-demethylase to a greater extent than tiamulin, whereas alpha-naphthoflavone, chloramphenicol, or sulphametasine was less effective. These results suggest that P-450 3A plays an important role in the oxidative metabolism of MON and that compounds capable of binding or inhibiting this isoenzyme could be expected to give rise to toxic interactions with the ionophore.

Dicty_cDB: Contig-U14247-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 22555 ) Zebrafish DNA sequence from clone DKEY-19D21 in l... 44 7.5 1 ( BV440136 ) S237P6107RD7.T0 Portugu...eseWaterDog Canis familiar... 44 7.5 1 ( AC158364 ) Mus musculus BAC clone RP23-187

Effects of amines, monensin and nigericin on the renin release from isolated superfused rat glomeruli

DEFF Research Database (Denmark)

Skøtt, O

1987-01-01

transiently. Alkalinization of the cell interior was achieved with weak permeable bases and ionophores. At low concentrations (5 mM NH4Cl; 0.2 mM chloroquine) the weak bases caused a delayed inhibition of the RR, while at higher concentrations (15 and 30 mM NH4Cl; 10 mM methylamine) the inhibitory effect...... was overlaid with a transient stimulation. 1.5 mM NH4Cl and 10 and 20 microM chloroquine had no effect. Addition of 10 microM of the Na-H ionophore monensin also caused a transient stimulation followed by a progressive inhibition. 0.1 microM monensin had no effect. The above procedures cause increases in both...

Biomimetic supercontainers for size-selective electrochemical sensing of molecular ions

Science.gov (United States)

Netzer, Nathan L.; Must, Indrek; Qiao, Yupu; Zhang, Shi-Li; Wang, Zhenqiang; Zhang, Zhen

2017-04-01

New ionophores are essential for advancing the art of selective ion sensing. Metal-organic supercontainers (MOSCs), a new family of biomimetic coordination capsules designed using sulfonylcalix[4]arenes as container precursors, are known for their tunable molecular recognition capabilities towards an array of guests. Herein, we demonstrate the use of MOSCs as a new class of size-selective ionophores dedicated to electrochemical sensing of molecular ions. Specifically, a MOSC molecule with its cavities matching the size of methylene blue (MB+), a versatile organic molecule used for bio-recognition, was incorporated into a polymeric mixed-matrix membrane and used as an ion-selective electrode. This MOSC-incorporated electrode showed a near-Nernstian potentiometric response to MB+ in the nano- to micro-molar range. The exceptional size-selectivity was also evident through contrast studies. To demonstrate the practical utility of our approach, a simulated wastewater experiment was conducted using water from the Fyris River (Sweden). It not only showed a near-Nernstian response to MB+ but also revealed a possible method for potentiometric titration of the redox indicator. Our study thus represents a new paradigm for the rational design of ionophores that can rapidly and precisely monitor molecular ions relevant to environmental, biomedical, and other related areas.

Altered sensitivity of system A amino acid transport to ouabain in normal and transformed C3H-10T1/2 cells during the cell cycle

International Nuclear Information System (INIS)

Leister, K.J.; Schenerman, M.A.; Racker, E.

1989-01-01

Quiescent C3H-10T1/2 mouse fibroblasts that have not undergone any type of stress have a relatively low rate of 2-aminoisobutyrate (Aib) uptake by means of system A, which is primarily energized by the transmembrane Na + chemical gradient potential. System A activity in these cells is not sensitive to ouabain or proton ionophores. In contrast, methylcholanthrene-transformed and cofluent C3H-10T1/2 cells treated with ouabain utilize the membrane potential generated by the Na + , K + -ATPase pump to drive Aib transport by means of system A as shown by the sensitivity of transport activity to ouabain and proton ionophores. Since glucose is present during the assay, the proton ionophores do not affect the availability of ATP, as indicated by the undiminished uptake of 86 Rb + by the Na + , K + -ATPase pump. As cells progress through the G 1 phase of the cell cycle, they show an increased system A activity prior to entry into the S phase, which is also dependent on the electrogenicity of the Na + , K + -ATPase pump. There appears to be in all these cases a qualitative shift in the bioenergetic mechanism for the uptake of Aib as well as a marked quantitative increase in Aib uptake. The high activity after ouabain treatment was sustained in the transformed cells after removal of the ouabain, whereas in the confluent 10T1/2 cells the rate of uptake decayed rapidly, suggesting a difference in the mode of regulation. The authors conclude that transformed cells and normal cells in late G 1 or under stress make use of the membrane potential generated by the Na + , K + -ATPase pump to drive amino acid uptake by means of system A

Development of a pH sensing membrane electrode based on a new calix[4]arene derivative.

Science.gov (United States)

Kormalı Ertürün, H Elif; Demirel Özel, Ayça; Sayın, Serkan; Yılmaz, Mustafa; Kılıç, Esma

2015-01-01

A new pH sensing poly(vinyl chloride) (PVC) membrane electrode was developed by using recently synthesized 5,17-bis(4-benzylpiperidine-1-yl)methyl-25,26,27,28-tetrahydroxy calix[4]arene as an ionophore. The effects of membrane composition, inner filling solution and conditioning solution on the potential response of the proposed pH sensing membrane electrode were investigated. An optimum membrane composition of 3% ionophore, 67% o-nitrophenyl octyl ether (o-NPOE) as plasticizer, 30% PVC was found. The electrode exhibited a near-Nernstian slope of 58.7±1.1 mV pH(-1) in the pH range 1.9-12.7 at 20±1 °C. It showed good selectivity for H(+) ions in the presence of some cations and anions and a longer lifetime of at least 12 months when compared with the other PVC membrane pH electrodes reported in the literature. Having a wide working pH range, it was not only applied as a potentiometric indicator electrode in various acid-base titrations, but also successfully employed in different real samples. It has good reproducibility and repeatability with a response time of 6-7s. Compared to traditional glass pH electrode, it exhibited excellent potentiometric response after being used in fluoride-containing media. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of commonly used anticoccidials and antibiotics in a subclinical necrotic enteritis model

OpenAIRE

Lanckriet , Anouk; Timbermont , Leen; De Gussem , Maarten; Marien , Maja; Vancraeynest , Dieter; Haesebrouck , Freddy; Ducatelle , Richard; Van Immerseel , Filip

2010-01-01

Abstract Necrotic enteritis poses an important health risk to broilers. The ionophore anticoccidials lasalocid, salinomycin, maduramicin, narasin and a combination of narasin and nicarbazin were tested in feed for their prophylactic effect on the incidence of necrotic enteritis in a subclinical experimental infection model that uses coccidia as predisposing factor. In addition, drinking water medication with the antibiotics amoxicillin, tylosin and lincomycin was evaluated as curat...

Molecular mechanisms behind the antimicrobial activity of hop iso-α-acids in Lactobacillus brevis.

Science.gov (United States)

Schurr, Benjamin C; Hahne, Hannes; Kuster, Bernhard; Behr, Jürgen; Vogel, Rudi F

2015-04-01

The main bittering component in beer, hop iso-α-acids, have been characterised as weak acids, which act as ionophores impairing microbial cells' function under acidic conditions as present in beer. Besides medium pH, divalent cations play a central role regarding the efficacy of the antimicrobial effect. The iso-α-acids' non-bitter derivatives humulinic acids can be found in isomerised hop extracts and can be generated during hop storage. Therefore, they have been under investigation concerning their influence on beer sensory properties. This study sketches the molecular mechanism behind iso-α-acids' antimicrobial activity in Lactobacillus (L.) brevis regarding their ionophore activity versus the dependence of the inhibitory potential on manganese binding, and suggests humulinic acids as novel tasteless food preservatives. We designed and synthesised chemically modified iso-α-acids to enhance the basic understanding of the molecular mechanism of antimicrobial iso-α-acids. It could be observed that a manganese-binding dependent transmembrane redox reaction (oxidative stress) plays a crucial role in inhibition. Privation of an acidic hydroxyl group neither erased ionophore activity, nor did it entirely abolish antimicrobial activity. Humulinic acids proved to be highly inhibitory, even outperforming iso-α-acids. Copyright © 2014 Elsevier Ltd. All rights reserved.

An efficient ab initio DFT and PCM assessment of the potentiometric selectivity of a salophen type Schiff base.

Science.gov (United States)

Demir, Serkan; Yilmaz, Hakan; Dilimulati, Maowulidan; Andaç, Müberra

2014-06-01

As a neutral carrier component for the preparation of a potentiometric membrane sensor, the affinity and selectivity of the salophen type Schiff base ligand obtained by 1:2 condensation of 2.3-diaminopyridine with salicylaldehyde toward a series of common cations has been fully examined by DFT/B3LYP and integral equation formalism polarizable continum model (IEF-PCM or only given with PCM as default input in the computations) in combination with the experimental data. Both the potentiometric measurements and DFT calculations have exhibited that the ionophore shows appreciable selectivity for Cu(2+) ion over other cations. Four different approaches where the last three are the modified version of each other have been evaluated and compared with potentiometric data. Based upon the results of comparison among the approaches suggested to verify the selective behavior of ionophore toward Cu(2+), PCM implemented approach having a whole computational groundwork has given well-matched results with the observed data and with the method augmented with experimental hydration energies. The foremost interferences were detected by determining potentiometric selectivity coefficients for each metal ion relative to Cu(2+) and compared to the results obtained by the DFT calculations.

Activation of AMPK inhibits cervical cancer cell growth through AKT/FOXO3a/FOXM1 signaling cascade

International Nuclear Information System (INIS)

Yung, Mingo Ming Ho; Chan, David Wai; Liu, Vincent Wing Sun; Yao, Kwok-Ming; Ngan, Hextan Yuen-Sheung

2013-01-01

Although advanced-stage cervical cancer can benefit from current treatments, approximately 30% patients may fail after definitive treatment eventually. Therefore, exploring alternative molecular therapeutic approaches is imperatively needed for this disease. We have recently shown that activation of AMP-activated protein kinase (AMPK), a metabolic sensor, hampers cervical cancer cell growth through blocking the Wnt/β-catenin signaling activity. Here, we report that activated AMPK (p-AMPK) also inhibits cervical cancer cell growth by counteracting FOXM1 function. Effect of the activation of AMPK on FOXM1 expression was examined by hypoxia and glucose deprivation, as well as pharmacological AMPK activators such as A23187, AICAR and metformin. RT Q-PCR and Western blot analysis were employed to investigate the activities of AMPK, FOXM1 and AKT/FOXO3a signaling. Consistent with our previous findings, the activation of AMPK by either AMPK activators such as AICAR, A23187, metformin, glucose deprivation or hypoxia significantly inhibited the cervical cancer cell growth. Importantly, we found that activated AMPK activity was concomitantly associated with the reduction of both the mRNA and protein levels of FOXM1. Mechanistically, we showed that activated AMPK was able to reduce AKT mediated phosphorylation of p-FOXO3a (Ser253). Interestingly, activated AMPK could not cause any significant changes in FOXM1 in cervical cancer cells in which endogenous FOXO3a levels were knocked down using siRNAs, suggesting that FOXO3a is involved in the suppression of FOXM1. Taken together, our results suggest the activated AMPK impedes cervical cancer cell growth through reducing the expression of FOXM1

Internal magnesium, 2,3-diphosphoglycerate, and the regulation of the steady-state volume of human red blood cells by the Na/K/2Cl cotransport system

Science.gov (United States)

1992-01-01

This study is concerned with the relationship between the Na/K/Cl cotransport system and the steady-state volume (MCV) of red blood cells. Cotransport rate was determined in unfractionated and density- separated red cells of different MCV from different donors to see whether cotransport differences contribute to the difference in the distribution of MCVs. Cotransport, studied in cells at their original MCVs, was determined as the bumetanide (10 microM)-sensitive 22Na efflux in the presence of ouabain (50 microM) after adjusting cellular Na (Nai) and Ki to achieve near maximal transport rates. This condition was chosen to rule out MCV-related differences in Nai and Ki that might contribute to differences in the net chemical driving force for cotransport. We found that in both unfractionated and density-separated red cells the cotransport rate was inversely correlated with MCV. MCV was correlated directly with red cell 2,3-diphosphoglycerate (DPG), whereas total red cell Mg was only slightly elevated in cells with high MCV. Thus intracellular free Mg (Mgifree) is evidently lower in red cells with high 2,3-DPG (i.e., high MCV) and vice versa. Results from flux measurements at their original MCVs, after altering Mgifree with the ionophore A23187, indicated a high Mgi sensitivity of cotransport: depletion of Mgifree inhibited and an elevation of Mgifree increased the cotransport rate. The apparent K0.5 for Mgifree was approximately 0.4 mM. Maximizing Mgifree at optimum Nai and Ki minimized the differences in cotransport rates among the different donors. It is concluded that the relative cotransport rate is regulated for cells in the steady state at their original cell volume, not by the number of copies of the cotransporter but by differences in Mgifree. The interindividual differences in Mgifree, determined primarily by differences in the 2,3-DPG content, are responsible for the differences in the relative cotransport activity that results in an inverse relationship

Development of pvc membrane based potentiometric pH sensor using amine type neutral carrier

International Nuclear Information System (INIS)

Khan, M.F.

1999-01-01

The glass membrane-based pH-electrode has proved its utility over decades. However some limitations are associated with these type of sensors. It can not be used for measuring pH of hydrofluoric acid solution and is difficult to miniaturize for biological applications due to its high resistance and fragility. In the present investigation modified PVC-membranes have been cast by incorporating lipophilic salt tetrabutyl ammonium tetraphenylborate and sodium tetraphenylborate along with electro active compound tri-n-octylamine as neutral carrier. The performance comparison of fabricated pH-sensitive membrane electrode has been carried out regarding their Nernstian slope and life time. The performance comparison of the membrane electrodes fabricated from laboratory grade tri-n-octylamine and those prepared from highly purified ionophore was also carried out. The slopes of the modified membrane electrodes based on pure ionophore were 59 mV/decade H/sup +/ ions and commercial ionophore 54 mV/decade H/sup +/ ions. The linear range was from pH 5-11. In the range of pH 6-10 response was excellent. The measurement of selectivity coefficients for the probable, interfering ions (anions and cations) were also carried out. (author)

A Reliable and Non-destructive Method for Monitoring the Stromal pH in Isolated Chloroplasts Using a Fluorescent pH Probe

Directory of Open Access Journals (Sweden)

Pai-Hsiang Su

2017-12-01

Full Text Available The proton gradient established by the pH difference across a biological membrane is essential for many physiological processes, including ATP synthesis and ion and metabolite transport. Currently, ionophores are used to study proton gradients, and determine their importance to biological functions of interest. Because of the lack of an easy method for monitoring the proton gradient across the inner envelope membrane of chloroplasts (ΔpHenv, whether the concentration of ionophores used can effectively abolish the ΔpHenv is not proven for most experiments. To overcome this hindrance, we tried to setup an easy method for real-time monitoring of the stromal pH in buffered, isolated chloroplasts by using fluorescent pH probes; using this method the ΔpHenv can be calculated by subtracting the buffer pH from the measured stromal pH. When three fluorescent dyes, BCECF-AM [2′,7′-bis-(2-carboxyethyl-5-(and-6-carboxyfluorescein acetoxymethyl ester], CFDA-SE [5(6-Carboxyfluorescein diacetate succinimidyl ester] and SNARF-1 carboxylic acid acetate succinimidyl ester were incubated with isolated chloroplasts, BCECF-AM and CFDA-SE, but not the ester-formed SNARF-1 were taken up by chloroplasts and digested with esterase to release high levels of fluorescence. According to its relatively higher pKa value (6.98, near the physiological pH of the stroma, BCECF was chosen for further development. Due to shielding of the excitation and emission lights by chloroplast pigments, the ratiometric fluorescence of BCECF was highly dependent on the concentration of chloroplasts. By using a fixed concentration of chloroplasts, a highly correlated standard curve of pH to the BCECF ratiometric fluorescence with an r-square value of 0.98 was obtained, indicating the reliability of this method. Consistent with previous reports, the light-dependent formation of ΔpHenv can be detected ranging from 0.15 to 0.33 pH units upon illumination. The concentration of the ionophore

[Phenotypic and functional features of NK and NKT cells in chronic hepatitis B].

Science.gov (United States)

Wu, Shaofei; Li, Man; Sun, Xuehua; Zhou, Zhenhua; Zhu, Xiaojun; Zhang, Xin; Gao, Yueqiu

2015-06-01

To detect the ratio of natural killer (NK)/natural killer T (NKT) cells in peripheral blood, the levels of NKG2D/NKG2A, interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α) in patients with chronic hepatitis B (CHB). Peripheral blood mononuclear cells (PBMCs) were harvested from CHB patients. The ratio of NK/NKT cells in PBMCs and the levels of NKG2D and NKG2A were detected by flow cytometry. The expressions of intracellular IFN-γ and TNF-α were analyzed by flow cytometry after the treatment with phorbol 12-myristate 13-acetate (PMA), brefeldin A (BFA) or ionomycin in vitro. The comparison between two groups was performed by independent sample t-test. The relationship of each index to hepatitis B virus load and serum alanine aminotransferase was analyzed by Pearson correlation analysis. Compared with healthy controls, CHB patients presented with significantly decreased peripheral blood NK/NKT cell ratio and significantly elevated proportions of NKG2A+ NK and NKG2A+NKT cells, and after the treatment with PMA/BFA/ionomycin, IFN-γ+ NK and IFN-γ+ NKT cells were significantly reduced in CHB patients. NK and NKT cells showed a reduced ratio, disordered receptor expressions and decreased cytokine secretion capacity in CHB patients.

Adult fast myosin pattern and Ca2+-induced slow myosin pattern in primary skeletal muscle culture

Science.gov (United States)

Kubis, Hans-Peter; Haller, Ernst-August; Wetzel, Petra; Gros, Gerolf

1997-01-01

A primary muscle cell culture derived from newborn rabbit muscle and growing on microcarriers in suspension was established. When cultured for several weeks, the myotubes in this model develop the completely adult pattern of fast myosin light and heavy chains. When Ca2+ ionophore is added to the culture medium on day 11, raising intracellular [Ca2+] about 10-fold, the myotubes develop to exhibit properties of an adult slow muscle by day 30, expressing slow myosin light as well as heavy chains, elevated citrate synthase, and reduced lactate dehydrogenase. The remarkable plasticity of these myotubes becomes apparent, when 8 days after withdrawal of the ionophore a marked slow-to-fast transition, as judged from the expression of isomyosins and metabolic enzymes, occurs. PMID:9108130

77 FR 15577 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Science.gov (United States)

2012-03-16

...-Apr-12 UT Logan Logan-Cache..... 2/3187 2/23/12 RNAV (GPS) RWY 17, Amdt 1. 5-Apr-12 VT Lyndonville... Paul Intl/Wold- 30L, ILS RWY Chamberlain. 30L (CAT II), Amdt 44A. 5-Apr-12 MN Minneapolis..... Minneapolis-St 2/6419 2/23/12 CONVERGING ILS Paul Intl/Wold- RWY 30L, Orig. Chamberlain. 5-Apr-12 MN Duluth...

Saiboku-to, a Kampo herbal medicine, inhibits LTC4 release from eosinophils

Directory of Open Access Journals (Sweden)

Koichi Hirai

1998-01-01

Full Text Available Saiboku-to (TJ-96, a traditional Kampo herbal formation, has been used in the treatment of bronchial asthma in Japan as an anti-allergy herbal medicine. We investigated the effect of TJ-96 on leukotriene (LTC4 release from eosinophils and basophils isolated from healthy volunteers. Pre-incubation of eosinophils with TJ-96 inhibited ionophore- or formyl-methionyl-leucyl-phenylalanine (FMLP-induced LTC4 generation by eosinophils in a dose-dependent fashion. The TJ-96 was more potent in the release by ionophore (IC50 = 60 mg/mL than the release induced by FMLP (IC50 = 300 mg/mL. Maximal inhibition was observed when eosinophils were pretreated with TJ-96 for 5 min. Although TJ-96 at high concentrations inhibited IgE-mediated histamine release from human basophils, inhibition of IgE-mediated LTC4 release was not statistically significant. The potent inhibitory activity was found in the extract of Glycyrrhiza root, one of the herbal components of TJ-96, but the inhibitory effects were not due to either glycyrrhizin or liquiritin, the main elements of the Glycyrrhiza root. These results raise the possibility that the clinical efficacy of TJ-96 is derived, at least in part, from its potent inhibitory effect on LTC4 release from eosinophils.

A novel ion selective sensor for promethium determination

International Nuclear Information System (INIS)

Gupta, Vinod K.; Jain, Rajeev; Hamdan, A.J.; Agarwal, Shilpi; Bharti, Arvind K.

2010-01-01

This is a first promethium 145 ion-selective sensor based on the comparative study of two Schiff base ligands (X 1 and X 2 ) as neutral ionophores. Effect of various plasticizers: 2-nitrophenyloctylether (o-NPOE), dibutyl phosphonate (DBP), dioctylphthalate (DOP), tri-(2-ethylhexyl) phosphate (TEHP), dibutyl butylphosphonate (DBBP), chloronaphthalene (CN) and anion excluders: potassium tetrakis (p-chloropheny1) borate (KTpClPB), sodiumtetraphenylborate (NaTPB) and oleic acid (OA) have been studied. The membrane with a composition of ionophore (X 1 /X 2 ):KTpClPB:PVC:o-NPOE (w/w, %) in the ratio of 5:5:30:60 exhibited best performance. The best responsive membrane sensors (8 and 21) exhibited working concentration range of 4.5 x 10 -7 -1.0 x 10 -2 M and 3.5 x 10 -6 -1.0 x 10 -2 M with a detection limits of 3.2 x 10 -7 M and 2.3 x 10 -6 M and Nernstian slopes of 20.0 ± 0.5, 19.5 ± 0.5 mV decade -1 of activity, respectively. The sensor no. 8 works satisfactorily in partially non-aqueous media up to 10% (v/v) content of methanol, ethanol and acetonitrile. Analytical application of the proposed sensor has been demonstrated in determination of promethium (III) ions in spiked water samples.

Fisetin, a flavonol, inhibits TH2-type cytokine production by activated human basophils.

Science.gov (United States)

Higa, Shinji; Hirano, Toru; Kotani, Mayumi; Matsumoto, Motonobu; Fujita, Akihito; Suemura, Masaki; Kawase, Ichiro; Tanaka, Toshio

2003-06-01

Activation of mast cells and basophils through allergen stimulation releases chemical mediators and synthesizes cytokines. Among these cytokines, IL-4, IL-13, and IL-5 have major roles in allergic inflammation. We sought to determine the potency of flavonoids (astragalin, fisetin, kaempferol, myricetin, quercetin, and rutin) for the inhibition of cytokine expression and synthesis by human basophils. The inhibitory effect of flavonoids on cytokine expression by stimulated KU812 cells, a human basophilic cell line, and freshly purified peripheral blood basophils was measured by means of semiquantitative RT-PCR and ELISA assays. The effects of flavonoids on transcriptional activation of the nuclear factor of activated T cells were assessed by means of electrophoretic mobility shift assays. Fisetin suppressed the induction of IL-4, IL-13, and IL-5 mRNA expression by A23187-stimulated KU812 cells and basophils in response to cross-linkage of the IgE receptor. Fisetin reduced IL-4, IL-13, and IL-5 synthesis (inhibitory concentration of 50% [IC(50)] = 19.4, 17.7, and 17.4 micromol/L, respectively) but not IL-6 and IL-8 production by KU812 cells. In addition, fisetin inhibited IL-4 and IL-13 synthesis by anti-IgE antibody-stimulated human basophils (IC(50) = 5.1 and 6.2 micromol/L, respectively) and IL-4 synthesis by allergen-stimulated basophils from allergic patients (IC(50) = 4.8 micromol/L). Among the flavonoids examined, kaempferol and quercetin showed substantial inhibitory activities in cytokine expression but less so than those of fisetin. Fisetin inhibited nuclear localization of nuclear factor of activated T cells c2 by A23187-stimulated KU812 cells. These results provide evidence of a novel activity of the flavonoid fisetin that suppresses the expression of T(H)2-type cytokines (IL-4, IL-13, and IL-5) by basophils.

A new calcineurin inhibition domain in Cabin1

International Nuclear Information System (INIS)

Jang, Hyonchol; Cho, Eun-Jung; Youn, Hong-Duk

2007-01-01

Calcineurin (CN), a calcium-activated phosphatase, plays a critical role in various biological processes including T cell activation. Cabin1, a calcineurin binding protein 1, has been shown to bind directly to CN using its C-terminal region and inhibit CN activity. However, no increase in CN activity has been found in Cabin1ΔC T cells, which produce a truncated Cabin1 lacking the C-terminal CN binding region. Here, we report that Cabin1 has additional CN binding domain in its 701-900 amino acid residues. Cabin1 (701-900) blocked both CN-mediated dephosphorylation and nuclear import of NFAT and thus inhibited IL-2 production in response to PMA/ionomycin stimulation. This fact may explain why Cabin1ΔC mice previously showed no significant defect in CN-mediated signaling pathway

Pyrrolidine constrained bipyridyl-dansyl click fluoroionophore as selective Al(3+)sensor.

Science.gov (United States)

Maity, Debabrata; Govindaraju, T

2010-07-07

A pyrrolidine constrained bipyridyl-dansyl (ionophore-fluorophore) conjugate with triazole linker was synthesised through click chemistry. The fluoroionophore serves as a selective ratiometric and colorimetric chemosensor for Al(3+) based on internal charge transfer (ICT).

HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

NARCIS (Netherlands)

STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

1993-01-01

It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free

Immunomodulatory effects of the fungicide Mancozeb in agricultural workers

International Nuclear Information System (INIS)

Corsini, Emanuela; Birindelli, Sarah; Fustinoni, Silvia; De Paschale, Gioia; Mammone, Teresa; Visentin, Sara; Galli, Corrado L.; Marinovich, Marina; Colosio, Claudio

2005-01-01

Available data suggest that ethylenebisdithiocarbamates (EBDCs) may have immunomodulatory effects. This study aimed to investigate the immunological profile of farmers exposed to Mancozeb, an EBDC fungicide, through the determination of several serum, cellular, and functional immune parameters. Twenty-six healthy subjects entered the study, 13 vineyards exposed to Mancozeb and 13 unexposed controls. Exposure was assessed through the determination of ethylentiourea (ETU) in urine. Complete and differential blood count, serum immunoglobulins, complement fractions, autoantibodies, lymphocyte subpopulations, proliferative response to mitogens, natural killer (NK) activity, and cytokine production were measured. Post-exposure samples showed ETU urine concentration significantly higher than pre-exposure and control groups. A significant increase in CD19+ cells, both percentage and absolute number, and a significant decrease in the percentage of CD25+ cells were found in post-exposure samples compared to controls. A statistically significant increase in the proliferative response to phorbol myristate acetate plus ionomycin (PMA + ionomycin) was observed in the post-exposure group compared to controls and baseline, while a significant reduction in LPS-induced TNF-α release in post-exposure samples was observed. Overall, our results suggest that low-level exposure to Mancozeb has slight immunomodulatory effects, and point out a method adequate to reveal immune-modifications in workers occupationally exposed to potential immunotoxic compounds, based on a whole blood assay

Host Immunity via Mutable Virtualized Large-Scale Network Containers

Science.gov (United States)

2016-07-25

Programs, P.O. Box 8795, REPORT NUMBER Williamsburg, VA 23187-8795 9. SPONSORING/ MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM...Second, we need to mitigate the threat from insiders. Though the system only allows authenticated clients to locate and access it service, insiders...and constrain the distributed persistent inside crawlers that have va.lid credentials to access the web services. The main idea is to add a marker

Silver ion recognition using potentiometric sensor based on recently synthesized isoquinoline-1,3-dione derivatives

Directory of Open Access Journals (Sweden)

AJAR KAMAL

2012-08-01

Full Text Available The four derivatives of isoquinoline-1,3-dione based on β-lactum (I-IV, have been explored as neutral ionophores for preparing poly(vinylchloride based polymeric membrane electrodes (PME selective to silver(I ions. The addition of sodium tetraphenylborate (NaTPB and dioctylsebacate (DOS as a plasticizer was found to improve the performance of ion selective electrodes. The best performance was obtained with PME-1 based on ionophore I having composition: ionophore (9.2 mg, PVC (100.1 mg, DOS (201.1 mg and NaTPB (1.5 mg in 5 mL tetrahydrofuran. The electrode response was linear with Nernstian slope of 58.44 mV/decade in the concentration range of 1.0 x 10-1 M to 5.0 x 10-6 M and detection limit of 5.83 x 10-6 M. It performs satisfactorily over wide pH range of 1.0-5.5. The proposed sensor can be used over a period of more than three months without any significant drift in potential and shows good selectivity to silver(I ion over a number of cations especially with no interference of mercury(II ions. Sharp end point was obtained when the sensor was used as an indicator electrode for the potentiometric titration of silver(I ions with chloride ions and therefore this electrode (PME-1 could be used for quantitative determination of silver(I ion in synthetic water, silver foil and dental amalgam samples.

The activity and compatibility of the antibiotic tiamulin with other drugs in poultry medicine--A review.

Science.gov (United States)

Islam, K M S; Klein, U; Burch, D G S

2009-11-01

Tiamulin hydrogen fumarate is a semisynthetic derivative of the diterpene antibiotic pleuromutilin used in poultry medicine to treat mainly Mycoplasma- and Brachyspira-related diseases. Its use over 30 yr has not generally increased the development of resistance to these pathogens but occasionally resistant isolates are encountered. Tiamulin administered at therapeutic levels is relatively quickly absorbed, metabolized in the liver, and eliminated from the body of the bird after a withdrawal period of 72 h, and as a result, meat products can be safely consumed. A zero withdrawal period for eggs has been granted in several European Union states. When administered with different drugs, tiamulin has been shown to have an enhanced activity with the tetracyclines. There is a strong interaction, even death, with the ionophore anticoccidials monensin, narasin, and salinomycin when tiamulin is used at therapeutic levels, but this is dose-related and low doses do not interact. It is thought to be caused by the preferential metabolism of tiamulin in the liver resulting in a build up of the ionophore leading to clinical signs of overdosage. Tiamulin shows a milder interaction, such as temporary growth depression, with maduramicin and semduramicin but is compatible with lasalocid. Although tiamulin shows small benefits in improving performance in healthy animals, its main production benefit is in the face of infection, as a true therapeutic antibiotic.

Transcriptomic analysis of mouse EL4 T cells upon T cell activation and in response to protein synthesis inhibition via cycloheximide treatment

OpenAIRE

Lim, Pek Siew; Hardy, Kristine; Peng, Kaiman; Shannon, Frances M.

2015-01-01

T cell activation involves the recognition of a foreign antigen complexed to the major histocompatibility complex on the antigen presenting T cell to the T cell receptor. This leads to activation of signaling pathways, which ultimately leads to induction of key cytokine genes responsible for eradication of foreign antigens. We used the mouse EL4 T cell as a model system to study genes that are induced as a result of T cell activation using phorbol myristate acetate (PMA) and calcium ionomycin...

Influence of ER leak on resting cytoplasmic Ca2+ and receptor-mediated Ca2+ signalling in human macrophage.

Science.gov (United States)

Layhadi, Janice A; Fountain, Samuel J

2017-06-03

Mechanisms controlling endoplasmic reticulum (ER) Ca 2+ homeostasis are important regulators of resting cytoplasmic Ca 2+ concentration ([Ca 2+ ] cyto ) and receptor-mediated Ca 2+ signalling. Here we investigate channels responsible for ER Ca 2+ leak in THP-1 macrophage and human primary macrophage. In the absence of extracellular Ca 2+ we employ ionomycin action at the plasma membrane to stimulate ER Ca 2+ leak. Under these conditions ionomycin elevates [Ca 2+ ] cyto revealing a Ca 2+ leak response which is abolished by thapsigargin. IP 3 receptors (Xestospongin C, 2-APB), ryanodine receptors (dantrolene), and translocon (anisomycin) inhibition facilitated ER Ca 2+ leak in model macrophage, with translocon inhibition also reducing resting [Ca 2+ ] cyto . In primary macrophage, translocon inhibition blocks Ca 2+ leak but does not influence resting [Ca 2+ ] cyto . We identify a role for translocon-mediated ER Ca 2+ leak in receptor-mediated Ca 2+ signalling in both model and primary human macrophage, whereby the Ca 2+ response to ADP (P2Y receptor agonist) is augmented following anisomycin treatment. In conclusion, we demonstrate a role of ER Ca 2+ leak via the translocon in controlling resting cytoplasmic Ca 2+ in model macrophage and receptor-mediated Ca 2+ signalling in model macrophage and primary macrophage. Copyright © 2017 Elsevier Inc. All rights reserved.

Bach2 represses the AP-1-driven induction of interleukin-2 gene transcription in CD4+ T cells

OpenAIRE

Jang, Eunkyeong; Lee, Hye Rim; Lee, Geon Hee; Oh, Ah-Reum; Cha, Ji-Young; Igarashi, Kazuhiko; Youn, Jeehee

2017-01-01

The transcription repressor Bach2 has been proposed as a regulator of T cell quiescence, but the underlying mechanism is not fully understood. Given the importance of interleukin-2 in T cell activation, we investigated whether Bach2 is a component of the network of factors that regulates interleukin-2 expression. In primary and transformed CD4+ T cells, Bach2 overexpression counteracted T cell receptor/CD28- or PMA/ionomycin-driven induction of interleukin-2 expression, and silencing of Bach2...

Ca2+ uptake and cellular integrity in rat EDL muscle exposed to electrostimulation, electroporation, or A23187

DEFF Research Database (Denmark)

Gissel, Hanne; Clausen, Torben

2003-01-01

We tested the hypothesis that increased Ca2+ uptake in rat extensor digitorum longus (EDL) muscle elicits cell membrane damage as assessed from release of the intracellular enzyme lactate dehydrogenase (LDH). This was done by using 1) electrostimulation, 2) electroporation, and 3) the Ca2+ ionoph...

Steric and Stereochemical Modulation in Pyridyl- and Quinolyl-Containing Ligands

Directory of Open Access Journals (Sweden)

Zhaohua Dai

2016-12-01

Full Text Available Nitrogen-containing pyridine and quinoline are outstanding platforms on which excellent ionophores and sensors for metal ions can be built. Steric and stereochemical effects can be used to modulate the affinity and selectivity of such ligands toward different metal ions on the coordination chemistry front. On the signal transduction front, such effects can also be used to modulate optical responses of these ligands in metal sensing systems. In this review, steric modulation of achiral ligands and stereochemical modulation in chiral ligands, especially ionophores and sensors for zinc, copper, silver, and mercury, are examined using published structural and spectral data. Although it might be more challenging to construct chiral ligands than achiral ones, isotropic and anisotropic absorption signals from a single chiroptical fluorescent sensor provide not only detection but also differentiation of multiple analytes with high selectivity.

Employment of Voltammetry in Studies of Transport Processes across Artificial Phospholipid Membranes

Czech Academy of Sciences Publication Activity Database

Šestáková, Ivana; Navrátil, Tomáš; Josypčuk, Bohdan

2016-01-01

Roč. 28, č. 11 (2016), s. 2754-2759 ISSN 1040-0397 Institutional support: RVO:61388955 Keywords : phospholipid membrane * cadmium * calcium ionophore (calcimycin) Subject RIV: CG - Electrochemistry Impact factor: 2.851, year: 2016

Some frontiers of research in basic ruminant nutrition

African Journals Online (AJOL)

research on energy metabolism covers mechanisms of energy generation in anaerobes ..... by the action of ionophores would be at distinct disadvantage unless they could couple ...... industrial utilization of renewable resources. New research ...

Neutrophil-induced human bronchial hyperresponsiveness in vitro--pharmacological modulation.

Science.gov (United States)

Hughes, J M; McKay, K O; Johnson, P R; Tragoulias, S; Black, J L; Armour, C L

1993-04-01

Although it has been postulated that inflammatory cells cause the bronchial hyperresponsiveness which is diagnostic of asthma, until recently there has been little direct evidence of such a link. We have recently shown that calcium ionophore-activated human neutrophils and eosinophils can induce a state of human airway hyperresponsiveness in vitro. In this study we have shown that the anti-inflammatory agent nedocromil sodium, 10(-7) M, inhibited the hyperresponsiveness induced by products released from ionophore activated neutrophils but did not inhibit the release of leukotriene B4 from the same cells. Neutrophil-induced bronchial hyperresponsiveness was also inhibited by pre-treatment of the bronchial tissues with a thromboxane A2 and prostaglandin receptor antagonist, GR32191, 10(-7) M. These findings indicate that cyclooxygenase products are involved in bronchial hyperresponsiveness induced by inflammatory cell products in vitro and that their release can be inhibited by nedocromil sodium.

Nitrate and bicarbonate selective CHEMFETs

NARCIS (Netherlands)

Antonisse, M.M.G.; Engbersen, Johannes F.J.; Reinhoudt, David

1995-01-01

The development of durable anion selective CHEMFET micro sensors is described. Selectivity in these sensors is either obtained from differences in hydration energy of the anions (the Hlofmeister series, giving nitrate selectivity) or by introduction of a new class of uranyl salophene ionophores

A Modified NK Cell Degranulation Assay Applicable for Routine Evaluation of NK Cell Function

Directory of Open Access Journals (Sweden)

Snehal Shabrish

2016-01-01

Full Text Available Natural killer (NK cells play important role in innate immunity against tumors and viral infections. Studies show that lysosome-associated membrane protein-1 (LAMP-1, CD107a is a marker for degranulation of NK and cytotoxic T cells and its expression is a sensitive marker for the cytotoxic activity determination. The conventional methods of determination of CD107a on NK cells involve use of peripheral blood mononuclear cells (PBMC or pure NK cells and K562 cells as stimulants. Thus, it requires large volume of blood sample which is usually difficult to obtain in pediatric patients and patients with cytopenia and also requires specialized laboratory for maintaining cell line. We have designed a flow cytometric assay to determine CD107a on NK cells using whole blood, eliminating the need for isolation of PBMC or isolate NK cells. This assay uses phorbol-12-myristate-13-acetate (PMA and calcium ionophore (Ca2+-ionophore instead of K562 cells for stimulation and thus does not require specialized cell culture laboratory. CD107a expression on NK cells using modified NK cell degranulation assay compared to the conventional assay was significantly elevated (p<0.0001. It was also validated by testing patients diagnosed with familial hemophagocytic lymphohistiocytosis (FHL with defect in exocytosis. This assay is rapid, cost effective, and reproducible and requires significantly less volume of blood which is important for clinical evaluation of NK cells.

Anticoccidial efficacy testing: In vitro Eimeria tenella assays as replacement for animal experiments.

Science.gov (United States)

Thabet, Ahmed; Zhang, Runhui; Alnassan, Alaa-Aldin; Daugschies, Arwid; Bangoura, Berit

2017-01-15

Availability of an accurate in vitro assay is a crucial demand to determine sensitivity of Eimeria spp. field strains toward anticoccidials routinely. In this study we tested in vitro models of Eimeria tenella using various polyether ionophores (monensin, salinomycin, maduramicin, and lasalocid) and toltrazuril. Minimum inhibitory concentrations (MIC 95 , MIC 50/95 ) for the tested anticoccidials were defined based on a susceptible reference (Houghton strain), Ref-1. In vitro sporozoite invasion inhibition assay (SIA) and reproduction inhibition assay (RIA) were applied on sensitive laboratory (Ref-1 and Ref-2) and field (FS-1, FS-2, and FS-3) strains to calculate percent of inhibition under exposure of these strains to the various anticoccidials (%I SIA and%I RIA, respectively). The in vitro data were related to oocyst excretion, lesion scores, performance, and global resistance indices (GI) assessed in experimentally infected chickens. Polyether ionophores applied in the RIA were highly effective at MIC 95 against Ref-1 and Ref-2 (%I RIA ≥95%). In contrast, all tested field strains displayed reduced to low efficacy (%I RIA animal model (p89%) against all strains used in this study. However, adjusted GI (GI adj ) for toltrazuril-treated groups exhibited differences between reference and field strains which might indicate varying sensitivity. RIA is a suitable in vitro tool to detect sensitivity of E. tenella towards polyether ionophores, and may thus help to reduce, replace, or refine use of animal experimentation for in vivo sensitivity assays. Copyright © 2016 Elsevier B.V. All rights reserved.

All-solid-state potassium-selective electrode using graphene as the solid contact

DEFF Research Database (Denmark)

Li, Fenghua; Ye, Junjin; Zhou, Min

2012-01-01

Graphene sheets are used for the first time to fabricate a new type of solid-contact ion-selective electrode (SC-ISE) as the intermediate layer between an ionophore-doped solvent polymeric membrane and a glassy carbon electrode. The new transducing layer was characterized by transmission electron...

Cardioplegia cristalóide, barotrauma e função endotelial: considerações experimentais Crystalloid cardioplegia, barotrauma and endothelium function: experimental considerations

Directory of Open Access Journals (Sweden)

Paulo Roberto B Évora

1996-06-01

effect the endothelium function of epicardic canine coronary arteries. These experiments did not show any alterations at level of receptors (dose-response curves to ACH and ADP; signal transduction/G-proteins (dose-response curve to sodium fluoride; intracellular mechanisms of the EDRF/NO release (dose-response curves to phospholipase C and calcium ionophores A23187. The smooth muscular relaxant function (dose-response curves to sodium nitroprusside and isoproterenol and contarctions (doseresponse curves to KCI and PGF2alpha were also preserved. These experimental observations allow the following speculative considerations: a Should barotrauma be a phenomenon present only in damaged coronary circulation? b All infusion were performed in no more than two or three minutes. Is cardioplegia barotrauma a phenomenon time-dependente? c High levels of potassium could be associated with barotrauma, d Cardioplegia barotrauma is a fancy, at least in our experimental conditions? e Experiments in "organ chambers" study only epicardic arteries. Could barotrauma damage the microcirculation? f The canine coronary circulation is less affeccted by high pressure than human coronaries? These data are suggestive that crystalloid moderately hyperkalemic infusions at high pressures for two or three minutes, do not impair the endothelium release of EDRF/NO of canine epicardic coronary arteries.

Effects of thapsigargin in isolated rat thoracic aorta

DEFF Research Database (Denmark)

Mikkelsen, E O; Thastrup, Ole; Christensen, S B

1988-01-01

The effect of thapsigargin (Tg) was studied in rat thoracic aorta. Tg (10(-8)-10(-5) M) had a dual effect on rat aorta. Thus, Tg induced a concentration dependent increase in basal tone in normal physiological salt solution (PSS), while Tg in potassium (K+) precontracted aortic rings caused a con...... A 23187 had an endothelium dependent relaxant effect on rat aorta different from that of carbachol. The results indicate that Tg in vascular smooth muscle acts by stimulating the transmembranal influx of extracellular calcium....

Development of a hexavalent chromium ISFET sensor with a polymeric membrane including tributylphosphate

International Nuclear Information System (INIS)

Zazoua, A.; Zougar, S.; Kherrat, R.; Samar, M.H.; Jaffrezic-Renault, N.; Errachid, A.; Abbaci, A.

2006-01-01

This paper presents a first report on chromium ISFET (ion-sensitive field effect transistor) based on a polymeric membrane (siloprene) including an ionophore (tributylphosphate) sensitive for hexavalent chromium. The sensor sensitivity as a function of the pH was studied; its value is minimum in a pH interval from 5.5 to 7.5. The sensitivity for hexavalent chromium was found to be 15 mV/loga Cr 6+ in the range of 10 -4 to 10 -2 M. The detection limit was found to be 10 -5 M. The studied interfering ions are Pb(II) and Cd(II) that do not represent a great perturbation upon the response for hexavalent chromium

Development of a hexavalent chromium ISFET sensor with a polymeric membrane including tributylphosphate

Energy Technology Data Exchange (ETDEWEB)

Zazoua, A. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Zougar, S. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Kherrat, R. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Samar, M.H. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Jaffrezic-Renault, N. [CEGELY-UMR 5005 CNRS, Ecole centrale de Lyon, 69134 Ecully cedex (France)]. E-mail: Nicole.Jaffrezic@ec-lyon.fr; Errachid, A. [Center of Reference for Bioengineering in Catalonia (CREBEC), Laboratory of Nanobioengineering, Parc Cientific de Barcelona, Universidad de Barcelona C/ Josep Samitier 1-5, 08028 Barcelona (Spain); Abbaci, A. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria)

2006-03-15

This paper presents a first report on chromium ISFET (ion-sensitive field effect transistor) based on a polymeric membrane (siloprene) including an ionophore (tributylphosphate) sensitive for hexavalent chromium. The sensor sensitivity as a function of the pH was studied; its value is minimum in a pH interval from 5.5 to 7.5. The sensitivity for hexavalent chromium was found to be 15 mV/loga {sub Cr{sup 6+}} in the range of 10{sup -4} to 10{sup -2} M. The detection limit was found to be 10{sup -5} M. The studied interfering ions are Pb(II) and Cd(II) that do not represent a great perturbation upon the response for hexavalent chromium.

Remote Loading of ⁶⁴Cu²⁺ into Liposomes without the Use of Ion Transport Enhancers

DEFF Research Database (Denmark)

Henriksen, Jonas Rosager; Petersen, Anncatrine Luisa; Hansen, Anders Elias

2015-01-01

Due to low ion permeability of lipid bilayers, it has been and still is common practice to use transporter molecules such as ionophores or lipophilic chelators to increase transmembrane diffusion rates and loading efficiencies of radionuclides into liposomes. Here, we report a novel and very simple...

Effect of Kisspeptin on the Developmental Competence and Early Transcript Expression in Porcine Oocytes Parthenogenetically Activated with Different Methods

Directory of Open Access Journals (Sweden)

Islam M. Saadeldin

2018-01-01

Full Text Available Recent studies showed the modulatory effect of kisspeptin (KP on calcium waves through the cell membrane and inside the cell. Spermatozoon can induce similar ooplasmic calcium oscillations at fertilization to trigger meiosis II. Here, we evaluated the effect of KP supplementation with 6-dimethylaminopurine (6-DMAP for 4 h on embryonic development after oocyte activation with single electric pulse, 5 µM ionomycin, or 8% ethanol. Compared to control nonsupplemented groups, KP significantly improved embryo developmental competence electric- and ethanol-activated oocytes in terms of cleavage (75.3% and 58.6% versus 64% and 48%, respectively, p<0.05 and blastocyst development (31.3% and 10% versus 19.3% and 4%, respectively, p<0.05. MOS expression was increased in electrically activated oocytes in presence of KP while it significantly reduced CCNB1 expression. In ionomycin treated group, both MOS and CCNB1 showed significant increase with no difference between KP and control groups. In ethanol-treated group, KP significantly reduced CCNB1 but no effect was observed on MOS expression. The early alterations in MOS and CCNB1 mRNA transcripts caused by KP may explain the significant differences in the developmental competence between the experimental groups. Kisspeptin supplementation may be adopted in protocols for porcine oocyte activation through electric current and ethanol to improve embryonic developmental competence.

Rapid determination of cadmium in rice using an all-solid RGO-enhanced light addressable potentiometric sensor.

Science.gov (United States)

Zhang, Wen; Xu, Yiwei; Zou, Xiaobo

2018-09-30

Herein, an all-solid light addressable potentiometric sensor (LAPS) is presented for determination of cadmium (Cd) in rice. On the working surface of the LAPS, reduced graphene oxide (RGO) is introduced as a part of ion-to-electron transducer to improve ionophore behaviors. The composite modification of RGO and ionophore is validated with scanning electron microscopy. The as-fabricated sensor presents a rapid response in less than 10 s to target Cd. Meanwhile, it shows lower noise (0.23 mV) and better limit of detection (0.002 mg L -1 ) than LAPS (control) without RGO modification (0.37 mV; 0.008 mg L -1 ). With the proposed method, satisfactory precision, accuracy and selectivity are also established. This method is adopted in an extensive survey for 25 rice samples from 5 regions in China. The results are in very good agreement with those obtained using inductively-coupled plasma-mass spectrometry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stuides on a Pb2+-selective electrode with a macrocyclic liquid membrane. Potentiometric determination of Pb2+ ions

Directory of Open Access Journals (Sweden)

MARIAN ISVORANU

2006-12-01

Full Text Available This paper presents experimental and theoretical data regarding the design, characterization and analytical applications of a non-expensive, liquid-membrane ion-selective electrode for Pb2+ ions. The membrane is a solution of the active complex formed by Pb2+ ions with dibenzo-18-crown-6-ionophore (DB-[18]-C-6 extracted in propylene carbonate (PC. The sucessful application of the developed electrode for the determination of Pb2+ ions in aqueos solution samples by direct potentiometry and potentiometric titration is presented. For the presented analytical results, there are insignificant systematic errors between the direct potentiometric method with the developed ion-selective electrode and atomic absorption spectrometry.

Application of cultured human mast cells (CHMC) for the design and structure-activity relationship of IgE-mediated mast cell activation inhibitors.

Science.gov (United States)

Argade, Ankush; Bhamidipati, Somasekhar; Li, Hui; Carroll, David; Clough, Jeffrey; Keim, Holger; Sylvain, Catherine; Rossi, Alexander B; Coquilla, Christina; Issakani, Sarkiz D; Masuda, Esteban S; Payan, Donald G; Singh, Rajinder

2015-01-01

Here we report the optimization of small molecule inhibitors of human mast cell degranulation via anti-IgE-mediated tryptase release following cross-linking and activation of IgE-loaded FcεR1 receptors. The compounds are selective upstream inhibitors of FcεR1-dependent human mast cell degranulation and proved to be devoid of activity in downstream ionomycin mediated degranulation. Structure-activity relationship (SAR) leading to compound 26 is outlined. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effects of an active live yeast product on the growth performance ...

African Journals Online (AJOL)

A study was conducted to evaluate the effects of a rumen-specific, active live yeast (Saccharomyces cerevisiae; SC CNCM I-1077), alone or in combination with an ionophore (lasalocid-Na) in standard feedlot diets, on production performance and carcass quality of lambs. Sixty South African (S.A.) Mutton Merino lambs, ...

Membrane electrodes for the determination of pyridostigmine bromide.

Science.gov (United States)

El-Kosasy, Amira M; Salem, Maissa Y; El-Bardicy, Mohamed G; Abd El-Rahman, Mohamed K

2009-01-01

Two pyridostigmine bromide (PB) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH), based on the interaction between the drug solution and the dissociated COOH groups in the PVC-COOH. One of the sensors was fabricated by using PVC-COOH only as anionic site without incorporation of an ionophore (sensor 1). The second sensor was constructed by using 2-hydroxy propyl beta-cyclodextrin as an ionophore (sensor 2). Linear responses of PB within a concentration range of 10(-3)-10(-2) and 10(-5)-10(-2) M, with slopes of 51.9 +/- 0.31 and 56.7 +/- 0.40 mV/decade over pH range of 5-10 were obtained using sensors 2 and 1, respectively. The proposed method displayed useful analytical characteristics for determination of PB in tablets with average recoveries of 100.22 +/- 0.62, and 100.15 +/- 0.72, and in plasma with average recoveries of 99.14 +/- 1.19 and 99.79 +/- 0.72, for sensors 2 and 1, respectively. The utility of 2-hydroxy propyl beta-cyclodextrin as an ionophore has a significant influence on increasing both membrane sensitivity and selectivity of sensor 2 in comparison with sensor 1. The methods were also used to determine the intact drug in the presence of its degradate, and thus could be used as stability-indicating methods. The results obtained by the proposed procedures were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method. No significant difference for either accuracy or precision was observed.

The fate and effect of monensin during anaerobic digestion of dairy manure under mesophilic conditions

Science.gov (United States)

There is growing concern about environmental impact of residual antibiotics and feed additives in the manure of treated animals. Monensin, a polyether ionophore coccidiostat, is the only feed additive permitted for use in the U.S. for lactating dairy cows. Previous research has shown that up to 5...

Regulation of calcium release from the endoplasmic reticulum by the serine hydrolase ABHD2.

Science.gov (United States)

Yun, Bogeon; Lee, HeeJung; Powell, Roger; Reisdorph, Nichole; Ewing, Heather; Gelb, Michael H; Hsu, Ku-Lung; Cravatt, Benjamin F; Leslie, Christina C

2017-09-02

The serine hydrolase inhibitors pyrrophenone and KT195 inhibit cell death induced by A23187 and H 2 O 2 by blocking the release of calcium from the endoplasmic reticulum and mitochondrial calcium uptake. The effect of pyrrophenone and KT195 on these processes is not due to inhibition of their known targets, cytosolic phospholipase A 2 and α/β-hydrolase domain-containing (ABHD) 6, respectively, but represent off-target effects. To identify targets of KT195, fibroblasts were treated with KT195-alkyne to covalently label protein targets followed by click chemistry with biotin azide, enrichment on streptavidin beads and tryptic peptide analysis by mass spectrometry. Although several serine hydrolases were identified, α/β-hydrolase domain-containing 2 (ABHD2) was the only target in which both KT195 and pyrrophenone competed for binding to KT195-alkyne. ABHD2 is a serine hydrolase with a predicted transmembrane domain consistent with its pull-down from the membrane proteome. Subcellular fractionation showed localization of ABHD2 to the endoplasmic reticulum but not to mitochondria or mitochondrial-associated membranes. Knockdown of ABHD2 with shRNA attenuated calcium release from the endoplasmic reticulum, mitochondrial calcium uptake and cell death in fibroblasts stimulated with A23187. The results describe a novel mechanism for regulating calcium transfer from the endoplasmic reticulum to mitochondria that involves the serine hydrolase ABHD2. Copyright © 2017 Elsevier Inc. All rights reserved.

Mouse splenic and bone marrow cell populations that express high-affinity Fc epsilon receptors and produce interleukin 4 are highly enriched in basophils.

OpenAIRE

Seder, R A; Paul, W E; Dvorak, A M; Sharkis, S J; Kagey-Sobotka, A; Niv, Y; Finkelman, F D; Barbieri, S A; Galli, S J; Plaut, M

1991-01-01

Splenic and bone marrow cells from normal mice, and from mice that have been polyclonally activated by injection of anti-IgD antibody, contain cells that produce interleukin 4 (IL-4) in response to crosslinkage of Fc epsilon receptors (Fc epsilon R) or Fc gamma R or to ionomycin. Isolated Fc epsilon R+ cells have recently been shown to contain all of the IL-4-producing capacity of the nonlymphoid compartment of spleen and bone marrow. Here, purified Fc epsilon R+ cells are shown to be enriche...

Effects of periodontal therapy on serum C-reactive protein, sE-selectin, and tumor necrosis factor-alpha secretion by peripheral blood-derived macrophages in diabetes. A pilot study.

Science.gov (United States)

Lalla, E; Kaplan, S; Yang, J; Roth, G A; Papapanou, P N; Greenberg, S

2007-06-01

Diabetes is associated with an increased risk for vascular disease and periodontitis. The aim of this study was to assess the effects of periodontal treatment in diabetes with respect to alterations in the pro-inflammatory potential of peripheral blood mononuclear cells. Ten patients with diabetes and moderate to severe periodontitis received full-mouth subgingival debridement. Blood samples for serum/plasma and mononuclear cell isolation were collected prior to and 4 wk after therapy. Mononuclear cells were analyzed by flow cytometry and stimulated with lipopolysaccharide or ionomycin/phorbol ester to determine the pro-inflammatory capacity of macrophages and lymphocytes, respectively. Following periodontal treatment, all patients demonstrated a significant improvement in clinical periodontal status (p C-reactive protein significantly decreased by 37% (p periodontal therapy and a potential impact on atherosclerosis-related complications in diabetic individuals.

Dicyclohexano-18-crown-6 as a novel carrier in the liquid membrane permeation of actinides

International Nuclear Information System (INIS)

Kumar, Anil; Singh, R.K.; Bajpai, D.D.; Shukla, J.P.

1994-01-01

The proven extractability and profound selectivity of dicyclohexano-18-crown-6 (DC18C6) has been exploited by selecting this crown ether as the ionophore in liquid membrane transport. Macrocycle-facilitated transport of Pu(IV) and U(VI) against their concentration gradient from aqueous nitric acid solutions across organic bulk liquid membrane (BLM) and thin-sheet supported liquid membrane (SLM) containing DC18C6 as the mobile carrier and toluene as the membrane solvent was investigated. (author). 23 refs., 9 tabs., 7 figs

Modulation pf pulmonary surfactant secretion from alveolar type II cells by cytoplasmic free calcium ([Ca2+]/sub i/)

International Nuclear Information System (INIS)

Sano, K.; Voelker, D.R.; Mason, R.J.

1986-01-01

Ca 2+ is regulator of a variety of cellular functions including exocytosis. TPA and terbutaline have been shown to stimulate surfactant secretion from alveolar type II cells. The authors examined changes in [Ca 2+ ]/sub i/ and surfactant secretion by secretagogues in primary culture of alveolar type II cells. Cells were isolated from adult rats and were cultured for 24 h with 3 H-choline to label phosphatidylcholine. Percent secretion was determined by counting the lipids of cells and medium; cytotoxicity was excluded by measuring lactate dehydrogenase as cells and medium. [Ca 2+ ]/sub i/ was determined by measuring quin2 fluroescence of cells cultured on a glass coverslip. Ionomycin increased secretion as well as [Ca 2+ ] in dose dependent manner at the concentration from 25 to 400 nM. Ionomycin (50 nM) increased terbutaline-induced secretion in a synergistic manner but only increased TPA-induced secretion in an additive manner. Terbutaline mobilized [Ca 2+ ]/sub i/ from intracellular stores and increased [Ca 2+ ]/sub i/ by 20% from a basal level of 140 nM. TPA itself did not change [Ca 2+ ]/sub i/ but inhibited the effect of terbutaline on [Ca 2+ ]/sub i/. Loading of quin2 in the absence of extracellular calcium lowered [Ca 2+ ]/sub i/ from 143 nM to 31 nM. Lowering [Ca 2+ ]/sub i/ inhibited TPA- or terbutaline-induced secretion by 22% and 40% respectively. These results indicate that [Ca 2+ ]/sub i/ effects cAMp-induced secretion more than protein kinase C-mediated secretion in alveolar type II cells

Graphene-based biomimetic materials targeting urine metabolite as potential cancer biomarker: application over different conductive materials for potentiometric transduction

Science.gov (United States)

Truta, Liliana A.A.N.A.; Ferreira, Nádia S.; Sales, M. Goreti F.

2015-01-01

This works presents a novel surface Smart Polymer Antibody Material (SPAM) for Carnitine (CRT, a potential biomarker of ovarian cancer), tested for the first time as ionophore in potentiometric electrodes of unconventional configuration. The SPAM material consisted of a 3D polymeric network created by surface imprinting on graphene layers. The polymer was obtained by radical polymerization of (vinylbenzyl)trimethylammonium chloride and 4-styrenesulfonic acid (signaling the binding sites), and vinyl pivalate and ethylene glycol dimethacrylate (surroundings). Non-imprinted material (NIM) was prepared as control, by excluding the template from the procedure. These materials were then used to produce several plasticized PVC membranes, testing the relevance of including the SPAM as ionophore, and the need for a charged lipophilic additive. The membranes were casted over solid conductive supports of graphite or ITO/FTO. The effect of pH upon the potentiometric response was evaluated for different pHs (2-9) with different buffer compositions. Overall, the best performance was achieved for membranes with SPAM ionophore, having a cationic lipophilic additive and tested in HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) buffer, pH 5.1. Better slopes were achieved when the membrane was casted on conductive glass (−57.4mV/decade), while the best detection limits were obtained for graphite-based conductive supports (3.6×10−5mol/L). Good selectivity was observed against BSA, ascorbic acid, glucose, creatinine and urea, tested for concentrations up to their normal physiologic levels in urine. The application of the devices to the analysis of spiked samples showed recoveries ranging from 91% (± 6.8%) to 118% (± 11.2%). Overall, the combination of the SPAM sensory material with a suitable selective membrane composition and electrode design has lead to a promising tool for point-of-care applications. PMID:26456975

Antiplatelet activity of Allium ursinum and Allium sativum.

Science.gov (United States)

Hiyasat, Bahi; Sabha, Dina; Grotzinger, Kristina; Kempfert, Joerg; Rauwald, Johann-Wilhelm; Mohr, Friedrich-Wilhelm; Dhein, Stefan

2009-01-01

Garlic (Allium sativum) has a well-established reputation as a protective agent against cardiovascular disease, while nearly nothing is known about its cousin Allium ursinum. The aim of this study was to evaluate the antiaggregatory mechanism of garlic and to compare the effects of A. ursinum and A. sativum. In a prospective study, extracts were prepared from A. sativum powder made from fresh A. sativum bulbs and fresh A. ursinum leaves by maceration. The extracts were characterized by thin layer chromatography. Their in vitro effects on human platelet aggregation were examined by light transmission aggregometry after induction by adenosine diphosphate (ADP), collagen, A23187, epinephrine and arachidonic acid (ARA) in platelets from healthy volunteers. A. ursinum and A. sativum exert similar antiaggregatory effects: they inhibit platelet aggregation induced via the ADP pathway and to a lesser extent aggregation induced by epinephrine, whereas ARA-, collagen- and A23187-induced aggregation was not affected. It became clear that the alcoholic extract of A. ursinum is the potent form, while the aqueous extract exerted an unspecific activity. The effects were strictly dose related. A. ursinum and A. sativum extracts exhibited similar potencies. Both A. ursinum and A. sativum exert antiaggregatory effects. Garlic extracts are acting by inhibition of the ADP pathway; their mechanisms of action are comparable to that of the clinically used drug clopidogrel. The pharmacologically active component of the extracts appears to be lipophilic rather than hydrophilic, but the precise chemical substance is still unknown. This is the first report on the antiplatelet activity of A. ursinum. Copyright 2009 S. Karger AG, Basel.

N-methyl-D-aspartate promotes the survival of cerebellar granule cells: pharmacological characterization

DEFF Research Database (Denmark)

Balázs, R; Hack, N; Jørgensen, Ole Steen

1989-01-01

The survival of cerebellar granule cells in culture is promoted by chronic exposure to N-methyl-D-aspartate (NMDA). The effect is due to the stimulation of 'conventional' NMDA receptor-ionophore complex: it is concentration dependent, voltage dependent and blocked by the selective antagonists D-2...

Comparative studies of neodymium (III)-selective PVC membrane sensors

Energy Technology Data Exchange (ETDEWEB)

Gupta, Vinod K., E-mail: vinodfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India); Goyal, Rajendra N.; Sharma, Ram A. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

2009-08-04

Sensors based on two neutral ionophores, N,N'-bis((1H-pyrrol-2-yl)methylene)cyclohexane-1,2-diamine (L{sub 1}) and 3,3'-(cyclohexane-1,2-diylbis(azan-1-yl-1-ylidene) bis(methan-1-yl-1-ylidene)bis(5-hydroxymethyl)pyridine-2-ol) (L{sub 2}) are described for quantification of neodymium (III). Effect of various plasticizers; 2-nitrophenyloctylether (o-NPOE), dibutyl butylphosphonate (DBBP), tri-n-butyl phosphates (TBP), dioctylpthalate (DOP) and chloronapthalen (CN) and anion excluder, sodiumtetraphenylborate (NaTPB) has been studied. The membrane composition of PVC:o-NPOE:ionophore (L{sub 1}):NaTPB (w/w; mg) of 150:300:5:5 exhibited best performance. The sensor with ionophore (L{sub 1}) exhibits significantly enhanced selectivity towards neodymium (III) in the concentration range 5.0 x 10{sup -7} to 1.0 x 10{sup -2} M with a detection limit of 1.0 x 10{sup -7} M and a Nernstian compliance (19.8 {+-} 0.3 mV decade{sup -1} of activity) within pH range 4.0-8.0. The response time of sensor was found as 10 s. The influence of the membrane composition and possible interfering ions has also been investigated on the response properties of the electrode. The fast and stable response, good reproducibility and long-term stability of the sensor are observed. The sensor has been found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol or acetonitrile and could be used for a period of 3 months. The selectivity coefficients determined by using fixed interference method (FIM) indicate high selectivity for neodymium. The proposed electrode shows fairly good discrimination of neodymium (III) from other cations. The application of prepared sensor has been demonstrated in the determination of neodymium (III) in spiked water samples.

The effect of dietary lipid saturation and monensin-Na on the CLA ...

African Journals Online (AJOL)

One diet contained no ionophore antibiotic and the other monensin-Na included at 165 g/ton. These two basal diets were supplemented, according to a 2 x 3 factorial design, with three lipid sources [i.e. 20 g/kg of either beef tallow, sunflower oil or a CLA oil concentrate] differing in saturation level and fatty acid profile.

Subpopulations in purified platelets adhering on glass.

Science.gov (United States)

Donati, Alessia; Gupta, Swati; Reviakine, Ilya

2016-06-22

Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process.

Solid-contact potentiometric sensors and multisensors based on polyaniline and thiacalixarene receptors for the analysis of some beverages and alcoholic drinks

Science.gov (United States)

Sorvin, Michail; Belyakova, Svetlana; Stoikov, Ivan; Shamagsumova, Rezeda; Evtugyn, Gennady

2018-04-01

Electronic tongue is a sensor array that aims to discriminate and analyze complex media like food and beverages on the base of chemometrics approaches for data mining and pattern recognition. In this review, the concept of electronic tongue comprising of solid-contact potentiometric sensors with polyaniline and thacalix[4]arene derivatives is described. The electrochemical reactions of polyaniline as a background of solid-contact sensors and the characteristics of thiacalixarenes and pillararenes as neutral ionophores are briefly considered. The electronic tongue systems described were successfully applied for assessment of fruit juices, green tea, beer and alcoholic drinks They were classified in accordance with the origination, brands and styles. Variation of the sensor response resulted from the reactions between Fe(III) ions added and sample components, i.e., antioxidants and complexing agents. The use of principal component analysis and discriminant analysis is shown for multisensor signal treatment and visualization. The discrimination conditions can be optimized by variation of the ionophores, Fe(III) concentration and sample dilution. The results obtained were compared with other electronic tongue systems reported for the same subjects.

Monitoring of praseodymium(III) ions in aqueous solutions, soil and sediment samples by a PVC membrane sensor based on a furan-triazole derivative

Energy Technology Data Exchange (ETDEWEB)

Pourjavid, Mohammad Reza [Islamic Azad University, Tehran (Iran, Islamic Republic of). Dept. of Medicinal Chemistry. Nuclear Science and Technology Research Institute; Rezaee, Mohammad; Hosseini, Majid Haji [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Razavi, Taherehsadat, E-mail: pourjavid@gmail.com [Research Institute of Petroleum Industry, Tehran (Iran, Islamic Republic of). Instrumental Analysis Dept.

2012-07-01

A furan-triazole derivative has been explored as an ionophore for preparation of a highly selective Pr(III) membrane sensor. The proposed sensor exhibits a Nernstian response for Pr(III) activity over a wide concentration range with a detection limit of 5.2 x 10{sup -8}M. Its response is independent of pH of the solution in the range 3.0-8.8 and offers the advantages of fast response time. To investigate the analytical applicability of the sensor, it was applied successfully as an indicator electrode in potentiometric titration of Pr(III) solution and also in the direct and indirect determination of trace Pr(III) ions in some samples. (author)

Salinomycin-induced polyneuropathy in cats: Morphologic and epidemiologic data

NARCIS (Netherlands)

Linde-Sipman, J.S. van der; Inch, T.S.G.A.M. van den; Nes, J.J. van; Verhagen, H.; Kersten, J.G.T.M.; Beynen, A.C.; Plekkringa, R.

1999-01-01

In April 1996, an outbreak of toxic polyneuropathy in cats occurred in the Netherlands. All cats had been fed one of two brands of dry cat food from one manufacturer. Chemical analyses of these foods, stomach contents, and liver and kidney of affected cats revealed contamination with the ionophor

Sub-nanomolar sensing of ionic mercury with polymeric electrospun nanofibers

Energy Technology Data Exchange (ETDEWEB)

Kacmaz, Sibel [University of Dokuz Eylul, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Izmir (Turkey); Ertekin, Kadriye, E-mail: kadriye.ertekin@deu.edu.tr [University of Dokuz Eylul, Faculty of Sciences, Department of Chemistry, 35160 Izmir (Turkey); University of Dokuz Eylul, Center for Fabrication and Application of Electronic Materials (EMUM), 35160 Izmir (Turkey); Suslu, Aslihan [University of Dokuz Eylul, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Izmir (Turkey); University of Dokuz Eylul, Faculty Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey); Ergun, Yavuz [University of Dokuz Eylul, Faculty of Sciences, Department of Chemistry, 35160 Izmir (Turkey); Celik, Erdal [University of Dokuz Eylul, Center for Fabrication and Application of Electronic Materials (EMUM), 35160 Izmir (Turkey); University of Dokuz Eylul, Faculty Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey); Cocen, Umit [University of Dokuz Eylul, Faculty Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey)

2012-03-15

Ethyl cellulose (EC) based electrospun nanofibers were exploited for sub-nanomolar level optical chemical sensing of ionic mercury. An azomethine ionophore was used as Hg (I) and Hg (II) sensing material. Ethyl cellulose nanofibers with varying amounts of the ionic liquid; 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF{sub 4}) were prepared and characterized. The nanofibers were fabricated by electrospinning technique. The offered chemosensor allow determination of mercury ions in a large linear working range between 1.0 Multiplication-Sign 10{sup -10} and 1.0 Multiplication-Sign 10{sup -4} mol L{sup -1}. Limit of detection was found to be 0.07 nM which makes this technique alternative to cold-vapor atomic absorption spectrometry (CV-AAS), flame emission methods and to inductively coupled plasma-mass spectrometry (ICP-MS). The electrospun nanofibers exhibited excellent sensitivity for Hg (II) with respect to the continuous thin films prepared with same composition. The observed high sensitivity can be attributed to the high surface area of the nanofibrous materials and enhanced diffusibility of the mercury ions to the ionophore.

5-tert-Butyl-2-(4'-[{sup 18}F]fluoropropynylphenyl)-1,3-dithiane oxides: potential new GABA{sub A} receptor radioligands

Energy Technology Data Exchange (ETDEWEB)

Li Xuehe; Jung, Yong-Woon; Snyder, Scott E.; Blair, Joseph; Sherman, Philip S.; Desmond, Timothy; Frey, Kirk A. [Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109 (United States); Kilbourn, Michael R. [Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109 (United States)], E-mail: mkilbour@umich.edu

2008-07-15

As potential new ligands targeting the binding site of {gamma}-aminobutyric acid (GABA) receptor ionophore, trans-5-tert-butyl-2-(4'-fluoropropynylphenyl)-2-methyl-1,1-dioxo-1, 3-dithiane (1) and cis/trans-5-tert-butyl-2-(4'-fluoropropynylphenyl)-2-methyl-1,1,3, 3-tetroxo-1,3-dithiane (2) were selected for radiolabeling and initial evaluation as in vivo imaging agents for positron emission tomography (PET). Both compounds exhibited identical high in vitro binding affinities (K{sub i}=6.5 nM). Appropriate tosylate-substituted ethynyl precursors were prepared by multistep syntheses involving stepwise sulfur oxidation and chromatographic isolation of desired trans isomers. Radiolabeling was accomplished in one step using nucleophilic [{sup 18}F]fluorination. In vivo biodistribution studies with trans-[{sup 18}F]1 and trans-[{sup 18}F]2 showed significant initial uptake into mouse brain and gradual washout, with heterogeneous regional brain distributions and higher retention in the cerebral cortex and cerebellum and lower retention in the striatum and pons-medulla. These regional distributions of the new radioligands correlated with in vitro and ex vivo measures of standard radioligands binding to the ionophore- and benzodiazepine-binding sites of GABA{sub A} receptor in rodent brain. A comparison of these results with previously prepared radiotracers for other neurochemical targets, including successes and failures as in vivo radioligands, suggests that higher-affinity compounds with increased retention in target brain tissues will likely be needed before a successful radiopharmaceutical for human PET imaging can be identified.

Ionophorous functions of phosphatidic acid in the plant cell

Czech Academy of Sciences Publication Activity Database

Medvedev, S.S.; Tankelyun, O.V.; Batov, A.Y.; Voronina, O.V.; Martinec, Jan; Macháčková, Ivana

2006-01-01

Roč. 53, č. 1 (2006), s. 39-47 ISSN 1021-4437 R&D Projects: GA MŠk 1P05ME825 Grant - others:Russian Foundation for Basic Research 05-04-49619 Institutional research plan: CEZ:AV0Z50380511 Keywords : Zea mays * phosphatidic acid * membrane vesicles Subject RIV: EF - Botanics Impact factor: 0.321, year: 2006

[ABIN1 is not involved in imatinib upregulating A20 to inhibit the activation of NF-κB pathway in Jurkat T cells].

Science.gov (United States)

Chen, Qian; Wang, Senlin; Lin, Chen; Chen, Shaohua; Zhao, Xiaoling; Li, Yangqiu

2017-05-01

Objective To investigate the effect of imatinib (IM) on the expressions of A20-binding inhibitor of NF-κB1 (ABIN1) and A20 in Jurkat T cells. Methods Jurkat T cells were treated with 25, 50 and 100 nmol/L IM for 24 hours. The mRNA and protein levels of ABIN1, A20 and NF-κB were detected by real-time quantitative PCR and Western blotting. Results IM significantly inhibited both mRNA and protein levels of ABIN1 and NF-κB, but raised the mRNA and protein levels of A20; while phorbol 12-myristate 13-acetate/ionomycin increased the expression levels of ABIN1 and A20 mRNA and protein. Conclusion IM could upregulate A20 protein to inhibit the activation of NF-κB pathway in Jurkat T cells, which was independent of the ABIN1 protein.

Calcium-dependent nitric oxide production is involved in the cytoprotective properties of n-acetylcysteine in glycochenodeoxycholic acid-induced cell death in hepatocytes

International Nuclear Information System (INIS)

Gonzalez-Rubio, Sandra; Linares, Clara I.; Bello, Rosario I.; Gonzalez, Raul; Ferrin, Gustavo; Hidalgo, Ana B.; Munoz-Gomariz, Elisa; Rodriguez, Blanca A.; Barrera, Pilar; Ranchal, Isidora; Duran-Prado, Mario; Aguilar-Melero, Patricia; De la Mata, Manuel; Muntane, Jordi

2010-01-01

The intracellular oxidative stress has been involved in bile acid-induced cell death in hepatocytes. Nitric oxide (NO) exerts cytoprotective properties in glycochenodeoxycholic acid (GCDCA)-treated hepatocytes. The study evaluated the involvement of Ca 2+ on the regulation of NO synthase (NOS)-3 expression during N-acetylcysteine (NAC) cytoprotection against GCDCA-induced cell death in hepatocytes. The regulation of Ca 2+ pools (EGTA or BAPTA-AM) and NO (L-NAME or NO donor) production was assessed during NAC cytoprotection in GCDCA-treated HepG2 cells. The stimulation of Ca 2+ entrance was induced by A23187 in HepG2. Cell death, Ca 2+ mobilization, NOS-1, -2 and -3 expression, AP-1 activation, and NO production were evaluated. GCDCA reduced intracellular Ca 2+ concentration and NOS-3 expression, and enhanced cell death in HepG2. NO donor prevented, and L-NAME enhanced, GCDCA-induced cell death. The reduction of Ca 2+ entry by EGTA, but not its release from intracellular stores by BAPTA-AM, enhanced cell death in GCDCA-treated cells. The stimulation of Ca 2+ entrance by A23187 reduced cell death and enhanced NOS-3 expression in GCDCA-treated HepG2 cells. The cytoprotective properties of NAC were related to the recovery of intracellular Ca 2+ concentration, NOS-3 expression and NO production induced by GCDCA-treated HepG2 cells. The increase of NO production by Ca 2+ -dependent NOS-3 expression during NAC administration reduces cell death in GCDCA-treated hepatocytes.

Calcium-dependent nitric oxide production is involved in the cytoprotective properties of n-acetylcysteine in glycochenodeoxycholic acid-induced cell death in hepatocytes

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Rubio, Sandra; Linares, Clara I; Bello, Rosario I [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Gonzalez, Raul; Ferrin, Gustavo [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Centro de Investigacion Biomedica en Red de Enfermedades Hepaticas y Digestivas (CIBEREH o Ciberehd) (Spain); Hidalgo, Ana B [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Munoz-Gomariz, Elisa [Department of Biostatistics, Reina Sofia University Hospital, Cordoba (Spain); Rodriguez, Blanca A [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Barrera, Pilar; Ranchal, Isidora [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Centro de Investigacion Biomedica en Red de Enfermedades Hepaticas y Digestivas (CIBEREH o Ciberehd) (Spain); Duran-Prado, Mario [Instituto de Parasitologia y Biomedicina Lopez Neyra, CSIC, Granada (Spain); CIBER Fisiopatologia de la Obesidad y Nutricion CB06/03, Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo (Spain); Aguilar-Melero, Patricia [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); De la Mata, Manuel [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Centro de Investigacion Biomedica en Red de Enfermedades Hepaticas y Digestivas (CIBEREH o Ciberehd) (Spain); Muntane, Jordi [Liver Research Unit, Reina Sofia University Hospital, Cordoba (Spain); Centro de Investigacion Biomedica en Red de Enfermedades Hepaticas y Digestivas (CIBEREH o Ciberehd) (Spain)

2010-01-15

The intracellular oxidative stress has been involved in bile acid-induced cell death in hepatocytes. Nitric oxide (NO) exerts cytoprotective properties in glycochenodeoxycholic acid (GCDCA)-treated hepatocytes. The study evaluated the involvement of Ca{sup 2+} on the regulation of NO synthase (NOS)-3 expression during N-acetylcysteine (NAC) cytoprotection against GCDCA-induced cell death in hepatocytes. The regulation of Ca{sup 2+} pools (EGTA or BAPTA-AM) and NO (L-NAME or NO donor) production was assessed during NAC cytoprotection in GCDCA-treated HepG2 cells. The stimulation of Ca{sup 2+} entrance was induced by A23187 in HepG2. Cell death, Ca{sup 2+} mobilization, NOS-1, -2 and -3 expression, AP-1 activation, and NO production were evaluated. GCDCA reduced intracellular Ca{sup 2+} concentration and NOS-3 expression, and enhanced cell death in HepG2. NO donor prevented, and L-NAME enhanced, GCDCA-induced cell death. The reduction of Ca{sup 2+} entry by EGTA, but not its release from intracellular stores by BAPTA-AM, enhanced cell death in GCDCA-treated cells. The stimulation of Ca{sup 2+} entrance by A23187 reduced cell death and enhanced NOS-3 expression in GCDCA-treated HepG2 cells. The cytoprotective properties of NAC were related to the recovery of intracellular Ca{sup 2+} concentration, NOS-3 expression and NO production induced by GCDCA-treated HepG2 cells. The increase of NO production by Ca{sup 2+}-dependent NOS-3 expression during NAC administration reduces cell death in GCDCA-treated hepatocytes.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Selectivity of the ionophore for Pb(II) ions was determined by spectrophotometric method. The electrode can also be used as an indicator electrode in potentiometric titration of Pb(II) ions with standard chromate solution and its determination in real-life samples. Surface morphology of membrane electrode at different stages ...

Rate and extent of ruminal degradation of crude protein from ...

African Journals Online (AJOL)

Predicted crude protein degradation was calculated at rate constants for outflow of 0.04 and 0.06/h respect- ively. ... as buffers, an ionophore and an antibiotic according to general .... the non-bird resistant ('sweet') varieties. Ruminal .... have been affected by both the particle type and the math- ematical model we used.

A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

International Nuclear Information System (INIS)

Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Yusof, Noor Azah; Tee, Tan Wee; Abdullah, Abd Halim; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Heng, Lee Yook

2011-01-01

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl + cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 x 10 -8 to 1.0 x 10 -1 M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu 2+ Ni 2+ and Pb 2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl + cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl + cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 x 10 -8 to 1.0 x 10 -1 M is linear with a Nernstian slope of 57.27 mV.

A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

Science.gov (United States)

Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Azah Yusof, Noor; Tee, Tan Wee; Yook Heng, Lee; Halim Abdullah, Abd

2011-02-01

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl+ cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 × 10-8 to 1.0 × 10-1M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu2+ Ni2+ and Pb2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl+ cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl+ cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 × 10-8 to 1.0 × 10-1M is linear with a Nernstian slope of 57.27 mV.

Mechanisms whereby insulin increases diacylglycerol in BC3H-1 myocytes.

Science.gov (United States)

Farese, R V; Cooper, D R; Konda, T S; Nair, G; Standaert, M L; Davis, J S; Pollet, R J

1988-01-01

/PE labelling by [3H]arachidonic acid, [3H]myristic acid, and [14C]choline. Phenylephrine, ionophore A23187 and phorbol esters did not increase [2-3H]glycerol incorporation into DAG or other glycerolipids in 2-h-prelabelling experiments; thus activation of the phospholipase C which hydrolyses phosphatidylinositol, its mono- and bis-phosphate, Ca2+ mobilization, and protein kinase C activation, appear to be ruled out as mechanisms to explain the insulin effect on synthesis de novo of PA, DAG and PC.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3146971

Automated patch-clamp technique: increased throughput in functional characterization and in pharmacological screening of small-conductance Ca2+ release-activated Ca2+ channels

DEFF Research Database (Denmark)

Schrøder, Rikke L; Friis, Søren; Sunesen, Morten

2008-01-01

require high signal-to-noise ratios obtained by high seal resistances. Automated whole-cell establishment resulted in membrane resistances of 1728 +/- 226 MOmega (n = 44). CRAC channels were activated by a number of methods that raise intracellular calcium concentration, including EGTA, ionomycin, Ins(1......, and the current could be reactivated by subsequent addition of thapsigargin. I(CRAC) was blocked by SKF-96365 and 2-APB with IC50 values of 4.7 +/- 1.1 microM (n = 9) and 7.5 +/- 0.7 (n = 9) microM, respectively. The potencies of these blockers were similar to values reported for I(CRAC) in similar conventional...

Effect of human bone marrow mesenchymal stromal cells on cytokine production by peripheral blood naive, memory, and effector T cells.

Science.gov (United States)

Laranjeira, Paula; Pedrosa, Monia; Pedreiro, Susana; Gomes, Joana; Martinho, Antonio; Antunes, Brigida; Ribeiro, Tania; Santos, Francisco; Trindade, Helder; Paiva, Artur

2015-01-05

The different distribution of T cells among activation/differentiation stages in immune disorders may condition the outcome of mesenchymal stromal cell (MSC)-based therapies. Indeed, the effect of MSCs in the different functional compartments of T cells is not completely elucidated. We investigated the effect of human bone marrow MSCs on naturally occurring peripheral blood functional compartments of CD4(+) and CD8(+) T cells: naive, central memory, effector memory, and effector compartments. For that, mononuclear cells (MNCs) stimulated with phorbol myristate acetate (PMA) plus ionomycin were cultured in the absence/presence of MSCs. The percentage of cells expressing tumor necrosis factor-alpha (TNF-α), interferon gamma (IFNγ), and interleukin-2 (IL-2), IL-17, IL-9, and IL-6 and the amount of cytokine produced were assessed by flow cytometry. mRNA levels of IL-4, IL-10, transforming growth factor-beta (TGF-β), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) in purified CD4(+) and CD8(+) T cells, and phenotypic and mRNA expression changes induced by PMA + ionomycin stimulation in MSCs, were also evaluated. MSCs induced the reduction of the percentage of CD4(+) and CD8(+) T cells producing TNF-α, IFNγ, and IL-2 in all functional compartments, except for naive IFNγ(+)CD4(+) T cells. This inhibitory effect differentially affected CD4(+) and CD8(+) T cells as well as the T-cell functional compartments; remarkably, different cytokines showed distinct patterns of inhibition regarding both the percentage of producing cells and the amount of cytokine produced. Likewise, the percentages of IL-17(+), IL-17(+)TNF-α(+), and IL-9(+) within CD4(+) and CD8(+) T cells and of IL-6(+)CD4(+) T cells were decreased in MNC-MSC co-cultures. MSCs decreased IL-10 and increased IL-4 mRNA expression in stimulated CD4(+) and CD8(+) T cells, whereas TGF-β was reduced in CD8(+) and augmented in CD4(+) T cells, with no changes for CTLA4. Finally, PMA + ionomycin

Calcium transport in vesicles energized by cytochrome oxidase

Energy Technology Data Exchange (ETDEWEB)

Rosier, Randy N. [Univ. of Rochester, NY (United States)

1979-01-01

Experiments on the reconstitution of cytochrome oxidase into phospholipid vesicles were carried out using techniques of selectivity energizing the suspensions with ascorbate and cytochrome c or ascorbate, PMS, and internally trapped cytochrome c. It was found that the K⁺ selective ionophore valinomycin stimulated the rate of respiration of cytochrome oxidase vesicles regardless of the direction of the K⁺ flux across the vesicle membranes. The stimulation occurred in the presence of protonophoric uncouplers and in the complete absence of potassium or in detergent-lysed suspensions. Gramicidin had similar effects and it was determined that the ionophores acted by specific interaction with cytochrome oxidase rather than by the previously assumed collapse of membrane potentials. When hydrophobic proteins and appropriate coupling factors were incorporated into the cytochrome oxidase, vesicles phosphorylation of ADP could be coupled to the oxidation reaction of cytochrome oxidase. Relatively low P:O, representing poor coupling of the system, were problematical and precluded measurements of protonmotive force. However the system was used to study ion translocation.

Influence of Introduced Substituents on the Anion-selectivity of [14]Tetraazaannulene Complexes.

Science.gov (United States)

Moriuchi-Kawakami, Takayo; Obita, Minako; Tsujinaka, Toshiki; Shibutani, Yasuhiko

2015-01-01

Nickel(II) complexes of [14]tetraazaannulene derivatives incorporating aromatic rings into their azaannulene framework were synthesized, and the anion-selectivity of the [14]tetraazaannulene nickel complexes 1 - 4 was evaluated by potentiometric measurements with solvent polymeric membrane electrodes. All of the [14]Tetraazaannulene nickel complexes, except 3, were found to exhibit high selectivity for the I(-) ion over the SCN(-) ion, although considerable interference of the ClO4(-) ion was observed in all 1 - 4 complexes. Concerning the anion-selectivities of 1 and 4, the incorporation of naphthalene rings into the azaannulene framework decreased not only the interference of the ClO4(-) ion but also the I(-) ion-selectivity over the SCN(-) ion. Comparison studies between the dibenzotetraaza[14]annulene nickel complexes 1 - 3 indicated that differences in the attached substituents of the [14]tetraazaannulene nickel complexes greatly influenced the ion-selectivity as ionophores. According to our computational results, the ionophoric properties of [14]tetraazaannulene nickel complexes 1 - 4 were influenced by their electrostatic properties rather than their topological properties.

Intracellular calcium signal at the leading edge regulates mesodermal sheet migration during Xenopus gastrulation.

Science.gov (United States)

Hayashi, Kentaro; Yamamoto, Takamasa S; Ueno, Naoto

2018-02-05

During the gastrulation stage in animal embryogenesis, the cells leading the axial mesoderm migrate toward the anterior side of the embryo, vigorously extending cell protrusions such as lamellipodia. It is thought that the leading cells sense gradients of chemoattractants emanating from the ectodermal cells and translate them to initiate and maintain the cell movements necessary for gastrulation. However, it is unclear how the extracellular information is converted to the intracellular chemical reactions that lead to motion. Here we demonstrated that intracellular Ca 2+ levels in the protrusion-forming leading cells are markedly higher than those of the following cells and the axial mesoderm cells. We also showed that inhibiting the intracellular Ca 2+ significantly retarded the gastrulation cell movements, while increasing the intracellular Ca 2+ with an ionophore enhanced the migration. We further found that the ionophore treatment increased the active form of the small GTPase Rac1 in these cells. Our results suggest that transient intracellular Ca 2+ signals play an essential role in the active cell migration during gastrulation.

Luteolin, a flavonoid, inhibits AP-1 activation by basophils

International Nuclear Information System (INIS)

Hirano, Toru; Higa, Shinji; Arimitsu, Junsuke; Naka, Tetsuji; Ogata, Atsushi; Shima, Yoshihito; Fujimoto, Minoru; Yamadori, Tomoki; Ohkawara, Tomoharu; Kuwabara, Yusuke; Kawai, Mari; Matsuda, Hisashi; Yoshikawa, Masayuki; Maezaki, Naoyoshi; Tanaka, Tetsuaki; Kawase, Ichiro; Tanaka, Toshio

2006-01-01

Flavonoids including luteolin, apigenin, and fisetin are inhibitors of IL-4 synthesis and CD40 ligand expression by basophils. This study was done to search for compounds with greater inhibitory activity of IL-4 expression and to clarify the molecular mechanisms through which flavonoids inhibit their expression. Of the 37 flavonoids and related compounds examined, ayanin, luteolin, and apigenin were the strongest inhibitors of IL-4 production by purified basophils in response to anti-IgE antibody plus IL-3. Luteolin did not suppress Syk or Lyn phosphorylation in basophils, nor did suppress p54/46 SAPK/JNK, p38 MAPK, and p44/42 MAPK activation by a basophilic cell line, KU812 cells, stimulated with A23187 and PMA. However, luteolin did inhibit phosphorylation of c-Jun and DNA binding activity of AP-1 in nuclear lysates from stimulated KU812 cells. These results provide a fundamental structure of flavonoids for IL-4 inhibition and demonstrate a novel action of flavonoids that suppresses the activation of AP-1

Enteric methane mitigation technologies for ruminant livestock: a synthesis of current research and future directions.

Science.gov (United States)

Patra, Amlan Kumar

2012-04-01

Enteric methane (CH(4)) emission in ruminants, which is produced via fermentation of feeds in the rumen and lower digestive tract by methanogenic archaea, represents a loss of 2% to 12% of gross energy of feeds and contributes to global greenhouse effects. Globally, about 80 million tonnes of CH(4) is produced annually from enteric fermentation mainly from ruminants. Therefore, CH(4) mitigation strategies in ruminants have focused to obtain economic as well as environmental benefits. Some mitigation options such as chemical inhibitors, defaunation, and ionophores inhibit methanogenesis directly or indirectly in the rumen, but they have not confirmed consistent effects for practical use. A variety of nutritional amendments such as increasing the amount of grains, inclusion of some leguminous forages containing condensed tannins and ionophore compounds in diets, supplementation of low-quality roughages with protein and readily fermentable carbohydrates, and addition of fats show promise for CH(4) mitigation. These nutritional amendments also increase the efficiency of feed utilization and, therefore, are most likely to be adopted by farmers. Several new potential technologies such as use of plant secondary metabolites, probiotics and propionate enhancers, stimulation of acetogens, immunization, CH(4) oxidation by methylotrophs, and genetic selection of low CH(4)-producing animals have emerged to decrease CH(4) production, but these require extensive research before they can be recommended to livestock producers. The use of bacteriocins, bacteriophages, and development of recombinant vaccines targeting archaeal-specific genes and cell surface proteins may be areas worthy of investigation for CH(4) mitigation as well. A combination of different CH(4) mitigation strategies should be adopted in farm levels to substantially decrease methane emission from ruminants. Evidently, comprehensive research is needed to explore proven and reliable CH(4) mitigation technologies

ANTI-ALLERGIC EFFECTS OF 1,5-BIS(4’-HYDROXY-3’-METHOXYPHENYL-1,4-PENTADIENE-3-ONE ON MAST CELL-MEDIATED ALLERGY MODEL

Directory of Open Access Journals (Sweden)

AGUNG ENDRO NUGROHO

2009-01-01

Full Text Available 1,5-bis(4’-hydroxy-3’-methoxyphenyl-1,4-pentadiene-3-one is a 1,5-diphenyl-1,4-pentadiene-3-one analogue of curcumin that is produced by modifying the middle site of curcumin leading to 1,4-pentadiene-3-ones to maintain the hydroxy moiety at the aromatic rings that are responsible for its biological activities. Curcumin has been reported to have anti-allergic effects and can inhibit the release of histamine from mast cells. In the present study, we evaluated the anti-allergic effects of 1,5-bis(4’-hydroxy-3’-methoxyphenyl-1,4-pentadiene-3-one in a mast cell-mediated allergy mode in order to provide information about a newly synthesised-compound for an alternative allergy drug. The study was performed using (1 a rat basophilic leukaemia (RBL-2H3 cell line, which is a tumour analogue of mast cells, with DNP24-BSA, thapsigargin and ionomycin as inducers for secretory markers from mast cells, and (2 an active cutaneous anaphylaxis (ACA reaction, with ovalbumin as an inductor of mast cell degranulation. Treatment with 1,5-bis(4’-hydroxy-3’-methoxyphenyl-1,4-pentadiene-3-one strongly inhibited the DNP24-BSA, thapsigargin and ionomycin-mediated release of histamine and β-hexosaminidase from the RBL-2H3 cell line. The results indicated that this compound influenced the activation processes of FcεRI by antigen and intracellular Ca2+ signalling events in mast cells. In type 1 allergy model, this compound also inhibited the active cutaneous anaphylactic reaction on rat dorsal skins generated by ovalbumin. We conclude that the compound 1,5-bis(4’-hydroxy-3’-methoxyphenyl-1,4-pentadiene-3-one showed anti-allergic activities mediated by mechanisms related to intracellular signalling events in mast cells.

Changes in the Th1 : Th2 Cytokine Bias in Pregnancy and the Effects of the Anti-Inflammatory Cyclopentenone Prostaglandin 15-Deoxy-Δ12,14-Prostaglandin J2

Directory of Open Access Journals (Sweden)

Lynne Sykes

2012-01-01

Full Text Available Pregnancy is a complex immunological state in which a bias towards T helper 2 (Th2 protects the fetus. Evidence suggests that proinflammatory cytokines increase the risk of poor neonatal outcome, independently of the direct effect of preterm labour. The anti-inflammatory prostaglandin 15-deoxy-Δ12,14-Prostaglandin J2 (15dPGJ2 inhibits nuclear factor Kappa B (NF-κB in amniocytes and myocytes in vitro and is a ligand for the chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2 receptor. Here we examine the Th1:Th2 cytokine bias in pregnancy and whether 15dPGJ2 could be used to inhibit the production of the proinflammatory cytokines through inhibition of NF-κB while simultaneously promoting Th2 interleukin 4 (IL-4 synthesis via CRTH2 in T helper cells. Peripheral blood mononuclear cells (PBMCs from women at 28 weeks, term pre-labour, term labour as well as non-pregnant female controls were cultured with 15dPGJ2 or vehicle control and stimulated with phorbol myristyl acetate (PMA/ionomycin. The percentage of CD4+ cells producing interferon gamma (IFN-γ and tumor necrosis factor alpha (TNF-α in response to PMA/ionomycin was significantly reduced in pregnancy. 15dPGJ2 reduced IFN-γ and TNF-α production in stimulated T helper cells, but did not alter IL-4 production in CRTH2+ve cells. 15dPGJ2 also reduced phospho-p65 in stimulated PBMCs. In summary, 15dPGJ2 suppresses the Th1 response of PBMCs during pregnancy and active labour whilst maintaining the Th2 response suggesting a therapeutic benefit in reducing neonatal morbidity in inflammation-induced PTL.

Gramicidin A: A New Mission for an Old Antibiotic

Directory of Open Access Journals (Sweden)

Justin M David

2015-01-01

Full Text Available Gramicidin A (GA is a channel-forming ionophore that renders biological membranes permeable to specific cations which disrupts cellular ionic homeostasis.  It is a well-known antibiotic, however it’s potential as a therapeutic agent for cancer has not been widely evaluated.  In two recently published studies, we showed that GA treatment is toxic to cell lines and tumor xenografts derived from renal cell carcinoma (RCC, a devastating disease that is highly resistant to conventional therapy.  GA was found to possess the qualities of both a cytotoxic drug and a targeted angiogenesis inhibitor, and this combination significantly compromised RCC growth in vitro and in vivo.  In this review, we summarize our recent research on GA, discuss the possible mechanisms whereby it exerts its anti-tumor effects, and share our perspectives on the future opportunities and challenges to the use of GA as a new anticancer agent.

Prevention of allergic rhinitis by ginger and the molecular basis of immunosuppression by 6-gingerol through T cell inactivation.

Science.gov (United States)

Kawamoto, Yoshiyuki; Ueno, Yuki; Nakahashi, Emiko; Obayashi, Momoko; Sugihara, Kento; Qiao, Shanlou; Iida, Machiko; Kumasaka, Mayuko Y; Yajima, Ichiro; Goto, Yuji; Ohgami, Nobutaka; Kato, Masashi; Takeda, Kozue

2016-01-01

The incidence of allergies has recently been increasing worldwide. Immunoglobulin E (IgE)-mediated hypersensitivity is central to the pathogenesis of asthma, hay fever and other allergic diseases. Ginger (Zingiber officinale Roscoe) and its extracts have been valued for their medical properties including antinausea, antiinflammation, antipyresis and analgesia properties. In this study, we investigated the antiallergic effects of ginger and 6-gingerol, a major compound of ginger, using a mouse allergy model and primary/cell line culture system. In mice with ovalbumin (OVA)-induced allergic rhinitis, oral administration of 2% ginger diet reduced the severity of sneezing and nasal rubbing by nasal sensitization of OVA and suppressed infiltration of mast cells in nasal mucosa and secretion of OVA-specific IgE in serum. 6-Gingerol inhibited the expression of not only Th2 cytokines but also Th1 cytokines in OVA-sensitized spleen cells. Accordingly, 6-gingerol suppressed in vitro differentiation of both Th1 cells and Th2 cells from naïve T cells. In addition, 6-gingerol suppressed both superantigen staphylococcal enterotoxin B (SEB)- and anti-CD3-induced T cell proliferation. 6-Gingerol also abrogated PMA plus ionomycin- and SEB-induced IL-2 production in T cells, suggesting that 6-gingerol affected T cell receptor-mediated signal transduction rather than the antigen-presentation process. Indeed, 6-gingerol inhibited the phosphorylation of MAP kinases, calcium release and nuclear localization of c-fos and NF-κB by PMA and ionomycin stimulation. Thus, our results demonstrate that 6-gingerol suppresses cytokine production for T cell activation and proliferation, thereby not causing B cell and mast cell activation and resulting in prevention or alleviation of allergic rhinitis symptoms. Copyright © 2015 Elsevier Inc. All rights reserved.

Circular Dichroism is Sensitive to Monovalent Cation Binding in Monensin Complexes

Czech Academy of Sciences Publication Activity Database

Nedzhib, A.; Kessler, Jiří; Bouř, Petr; Gyurcsik, B.; Pantcheva, I.

2016-01-01

Roč. 28, č. 5 (2016), s. 420-428 ISSN 0899-0042 R&D Projects: GA ČR GA15-09072S; GA ČR(CZ) GA16-05935S Institutional support: RVO:61388963 Keywords : monovalent polyether ionophore * metal complexes * synchrotron radiation circular dichroism * time-dependent density functional theory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.956, year: 2016

Neodymium(III PVC Membrane Electrodchemical Sensor Based on N-benzoylethylidene-2-aminobenzylamine

Directory of Open Access Journals (Sweden)

Hassan Ali Zamani

2012-01-01

Full Text Available The N-benzoylethylidene-2-aminobenzylamine (BEA was used as a suitable ionophore in construction of neodymium ion selective electrode. The electrode with composition of 30% PVC, 58% solvent mediator (NB, 2% ionophore (BEA and 10% anionic additive (OA shows the best potentiometric response characteristics. The Nd3+ sensor exhibits a Nernstian slope of 21.2 ± 0.2 mV decade-1 over the concentration range of 1.0 × 10-6 to 1.0 × 10-2 mol L-1, and a detection limit of 6.3 × 10-7 mol L-1 of Nd3+ ions. The potentiometric response of the sensor is independent of the solution pH in the range of 2.4–8.5. It has a very short response time, in the whole concentration range (~7 s, and can be used for at least eight weeks. The proposed sensor revealed high selectivity with respect to all common alkali, alkaline earth, transition and heavy metal ions, including members of the lanthanide family other than Nd3+. The Nd3+ sensor was successfully applied as an indicator electrode in the potentiometric titration of Nd3+ ions with EDTA. The electrode was also employed for the determination of the fluoride ion in two mouth wash preparations.

Interferon-¿ and interleukin-4 production by human T cells recognizing Leishmania donovani antigens separated by SDS-PAGE

DEFF Research Database (Denmark)

Bahrenscheer, J; Kemp, M; Kurtzhals, J A

1995-01-01

of proliferation and interferon-gamma (IFN-gamma) production in cultures of peripheral blood mononuclear cells (PBMC) from individuals who had recovered from visceral leishmaniasis caused by L. donovani. The release of interleukin-4 (IL-4) by PBMC stimulated with the isolated L. donovani antigen fractions...... was measured after treatment with phorbol-myristate-acetate and ionomycin. The cells proliferated in response to all protein fractions with molecular weights in the range production...... was infrequently observed. The results show that T cells from individuals who have been cured of visceral leishmaniasis recognize and respond to a wide range of leishmanial antigens. There was no evidence of particular fractions constantly giving either IFN-gamma or IL-4-producing responses....

DREAM plays an important role in platelet activation and thrombogenesis

Science.gov (United States)

Kim, Kyungho; Tseng, Alan; Barazia, Andrew; Italiano, Joseph E.

2017-01-01

Downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, is known to modulate pain responses. However, it is unknown whether DREAM is expressed in anucleate platelets and plays a role in thrombogenesis. By using intravital microscopy with DREAM-null mice and their bone marrow chimeras, we demonstrated that both hematopoietic and nonhematopoietic cell DREAMs are required for platelet thrombus formation following laser-induced arteriolar injury. In a FeCl3-induced thrombosis model, we found that compared with wild-type (WT) control and nonhematopoietic DREAM knockout (KO) mice, DREAM KO control and hematopoietic DREAM KO mice showed a significant delay in time to occlusion. Tail bleeding time was prolonged in DREAM KO control mice, but not in WT or DREAM bone marrow chimeric mice. In vivo adoptive transfer experiments further indicated the importance of platelet DREAM in thrombogenesis. We found that DREAM deletion does not alter the ultrastructural features of platelets but significantly impairs platelet aggregation and adenosine triphosphate secretion induced by numerous agonists (collagen-related peptide, adenosine 5′-diphosphate, A23187, thrombin, or U46619). Biochemical studies revealed that platelet DREAM positively regulates phosphoinositide 3-kinase (PI3K) activity during platelet activation. Using DREAM-null platelets and PI3K isoform-specific inhibitors, we observed that platelet DREAM is important for α-granule secretion, Ca2+ mobilization, and aggregation through PI3K class Iβ (PI3K-Iβ). Genetic and pharmacological studies in human megakaryoblastic MEG-01 cells showed that DREAM is important for A23187-induced Ca2+ mobilization and its regulatory function requires Ca2+ binding and PI3K-Iβ activation. These results suggest that platelet DREAM regulates PI3K-Iβ activity and plays an important role during thrombus formation. PMID:27903531

Selective electrochemical sensor for copper (II) ion based on chelating ionophores

International Nuclear Information System (INIS)

Singh, Ashok Kumar; Mehtab, Sameena; Jain, Ajay Kumar

2006-01-01

Plasticized membranes using 3-(2-pyridinyl)-2H-pyrido[1,2,-a]-1,3,5-triazine-2,4(3H)-dithione (L 1 ) and acetoacetanilide (L 2 ) have been prepared and explored as Cu 2+ -selective sensors. Effect of various plasticizers, viz. chloronaphthalene (China), benzyl acetate (BA), o-nitrophenyloctyl ether (o-NPOE), and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied in detail and improved performance was observed at several instances. Optimum performance was observed with dithione derivative (L 1 ) having a membrane composition of L 1 (5):PVC (120):o-NPOE (240):OA (10). The sensor works satisfactorily in the concentration range 5.0 x 10 -8 to 1.0 x 10 -2 M (detection limit 4.0 x 10 -8 M) with a Nernstian slope of 29.5 mV decade -1 of activity. Wide pH range (3.0-9.5), fast response time (12 s), non-aqueous tolerance (up to 20%) and adequate shelf life (4 months) indicate the vital utility of the proposed sensor. The potentiometric selectivity coefficient values as determined by match potential method (MPM) indicate good response for Cu 2+ in presence of interfering ions. The proposed electrode comparatively shows good selectivity with respect to alkali, alkaline earth, transition and some rare earth metals ions. The electrode was used for the determination of copper in different milk powder, water samples and as indicator electrode in potentiometric titration of copper ion with EDTA

Control of poultry coccidiosis: changing trends.

Science.gov (United States)

Tewari, A K; Maharana, B R

2011-06-01

Coccidiosis is the most important protozoan disease affecting the poultry industry worldwide. Control of poultry coccidiosis is presently based on managerial skills and the use of prophylactic coccidiostatic drugs. With the emergence of drug resistant Eimeria strains, emphasis has been laid on development and use of safer vaccines; some of them have been commercialized successfully. The present review deals with the various factors responsible for the development of clinical coccidiosis in poultry as well as an overview of the currently available inducers and boosters of immunity against coccidiosis. There are three groups of vaccines currently available against coccidiosis which can be distinguished on the basis of characteristics of the Eimeria species included in the respective products, viz. vaccines based on live virulent strains, vaccines based on live attenuated strains, and vaccines based on live strains that are relatively tolerant to the ionophore compounds. The latter vaccine combines the early chemotherapeutic effect of ionophores with the late prophylactic effect of vaccination. Although in the near future more varieties of oocyst based live vaccines are expected, identification of selective coccidian-specific immunoprotective molecules is likely to get more attention to facilitate the sustainable control of poultry coccidiosis.

Shikonin, a constituent of Lithospermum erythrorhizon exhibits anti-allergic effects by suppressing orphan nuclear receptor Nr4a family gene expression as a new prototype of calcineurin inhibitors in mast cells.

Science.gov (United States)

Wang, Xiaoyu; Hayashi, Shusaku; Umezaki, Masahito; Yamamoto, Takeshi; Kageyama-Yahara, Natsuko; Kondo, Takashi; Kadowaki, Makoto

2014-12-05

Over the last few decades, food allergy (FA) has become a common disease in infants in advanced countries. However, anti-allergic medicines available in the market have no effect on FA, and consequently effective drug therapies for FA are not yet available. We have already demonstrated that mucosal mast cells play an essential role in the development of FA in a murine model. Thus, we screened many constituents from medicinal herbs for the ability to inhibit rat basophilic leukemia-2H3 mast-like cell degranulation, and found that shikonin, a naphthoquinone dye from Lithospermum erythrorhizon, exhibited the most potent inhibitory effect among them. Furthermore, shikonin extremely inhibited the IgE/antigen-induced and calcium ionophore-induced upregulation of tumor necrosis factor (TNF)-α mRNA expression in mucosal-type bone marrow-derived mast cells (mBMMCs). Global gene expression analysis confirmed by real-time PCR revealed that shikonin drastically inhibited the IgE/antigen-induced and calcium ionophore-induced upregulation of mRNA expression of the nuclear orphan receptor 4a family (Nr4a1, Nr4a2 and Nr4a3) in mBMMCs, and knockdown of Nr4a1 or Nr4a2 suppressed the IgE/antigen-induced upregulation of TNF-α mRNA expression. Computational docking simulation of a small molecule for a target protein is a useful technique to elucidate the molecular mechanisms underlying the effects of drugs. Therefore, the simulation revealed that the predicted binding sites of shikonin to immunophilins (cyclophilin A and FK506 binding protein (FKBP) 12) were almost the same as the binding sites of immunosuppressants (cyclosporin A and FK506) to immunophilins. Indeed, shikonin inhibited the calcineurin activity to a similar extent as cyclosporin A that markedly suppressed the IgE/antigen-enhanced mRNA expression of TNF-α and the Nr4a family in mBMMCs. These findings suggest that shikonin suppresses mucosal mast cell activation by reducing Nr4a family gene expression through the

A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

Energy Technology Data Exchange (ETDEWEB)

Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Yusof, Noor Azah; Tee, Tan Wee; Abdullah, Abd Halim [Department of Chemistry Faculty of Science, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Rounaghi, Gholamhossein; Mohajeri, Masoomeh [Department of Chemistry, Factuality of Sciences, Islamic Azad University of Mashhad, Mashhad (Iran, Islamic Republic of); Heng, Lee Yook, E-mail: anuar@science.upm.edu.my [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E. (Malaysia)

2011-02-15

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl{sup +} cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 x 10{sup -8} to 1.0 x 10{sup -1}M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu{sup 2+} Ni{sup 2+} and Pb{sup 2+} cations, but the electrode has a wider dynamic range and a lower detection limit to Tl{sup +} cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl{sup +} cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 x 10{sup -8} to 1.0 x 10{sup -1}M is linear with a Nernstian slope of 57.27 mV.

Cannabinoid actions at TRPV channels: effects on TRPV3 and TRPV4 and their potential relevance to gastrointestinal inflammation.

Science.gov (United States)

De Petrocellis, L; Orlando, P; Moriello, A Schiano; Aviello, G; Stott, C; Izzo, A A; Di Marzo, V

2012-02-01

Plant cannabinoids, like Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD), activate/desensitize thermosensitive transient receptor potential (TRP) channels of vanilloid type-1 or -2 (TRPV1 or TRPV2). We investigated whether cannabinoids also activate/desensitize two other 'thermo-TRP's', the TRP channels of vanilloid type-3 or -4 (TRPV3 or TRPV4), and if the TRPV-inactive cannabichromene (CBC) modifies the expression of TRPV1-4 channels in the gastrointestinal tract. TRP activity was assessed by evaluating elevation of [Ca(2+)](i) in rat recombinant TRPV3- and TRPV4-expressing HEK-293 cells. TRP channel mRNA expression was measured by quantitative RT-PCR in the jejunum and ileum of mice treated with vehicle or the pro-inflammatory agent croton oil. (i) CBD and tetrahydrocannabivarin (THCV) stimulated TRPV3-mediated [Ca(2+)](i) with high efficacy (50-70% of the effect of ionomycin) and potency (EC(50∼) 3.7 μm), whereas cannabigerovarin (CBGV) and cannabigerolic acid (CBGA) were significantly more efficacious at desensitizing this channel to the action of carvacrol than at activating it; (ii) cannabidivarin and THCV stimulated TRPV4-mediated [Ca(2+)](i) with moderate-high efficacy (30-60% of the effect of ionomycin) and potency (EC(50) 0.9-6.4 μm), whereas CBGA, CBGV, cannabinol and cannabigerol were significantly more efficacious at desensitizing this channel to the action of 4-α-phorbol 12,13-didecanoate (4α-PDD) than at activating it; (iii) CBC reduced TRPV1β, TRPV3 and TRPV4 mRNA in the jejunum, and TRPV3 and TRPV4 mRNA in the ileum of croton oil-treated mice. Cannabinoids can affect both the activity and the expression of TRPV1-4 channels, with various potential therapeutic applications, including in the gastrointestinal tract. © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.

Generalized Selectivity Description for Polymeric Ion-Selective Electrodes Based on the Phase Boundary Potential Model.

Science.gov (United States)

Bakker, Eric

2010-02-15

A generalized description of the response behavior of potentiometric polymer membrane ion-selective electrodes is presented on the basis of ion-exchange equilibrium considerations at the sample-membrane interface. This paper includes and extends on previously reported theoretical advances in a more compact yet more comprehensive form. Specifically, the phase boundary potential model is used to derive the origin of the Nernstian response behavior in a single expression, which is valid for a membrane containing any charge type and complex stoichiometry of ionophore and ion-exchanger. This forms the basis for a generalized expression of the selectivity coefficient, which may be used for the selectivity optimization of ion-selective membranes containing electrically charged and neutral ionophores of any desired stoichiometry. It is shown to reduce to expressions published previously for specialized cases, and may be effectively applied to problems relevant in modern potentiometry. The treatment is extended to mixed ion solutions, offering a comprehensive yet formally compact derivation of the response behavior of ion-selective electrodes to a mixture of ions of any desired charge. It is compared to predictions by the less accurate Nicolsky-Eisenman equation. The influence of ion fluxes or any form of electrochemical excitation is not considered here, but may be readily incorporated if an ion-exchange equilibrium at the interface may be assumed in these cases.

A review of calixarene applications in nuclear industries

International Nuclear Information System (INIS)

Bahram Mokhtari; Iranian Offshore Oil Company, Lavan Island; Kobra Pourabdollah; Naser Dallali

2011-01-01

Calixarenes has been subject to extensive research in development of many extractants, transporters, stationary phases, electrode ionophores and optical and electrochemical sensors over the past four decades. In this paper, the nuclear applications of calixarenes are summarized in six fields including complexation studies, solvent extraction, membrane transport, chromatography, luminescent and colorimetric applications, and electroanalytical applications. In the first to fourth sections, the extractability, extraction equilibria and extraction constants of lanthanide, actinide and other nuclear waste cations ions, which were subjected to solvent extraction by the macrocyclic ligands, are reviewed. In two last sections, the analytical applications of calixarene complexes towards nuclear waste cations, including spectroscopic and electroanalytic sensors, are discussed. The examples described in this review illustrate the potential of calixarene derivatives in the rapidly growing field of cations recognition in nuclear wastes. (author)

A novel, fast responding, low noise potentiometric sensor containing a carbon-based polymeric membrane for measuring surfactants in industrial and environmental applications.

Science.gov (United States)

Samardžić, Mirela; Galović, Olivera; Hajduković, Mateja; Sak-Bosnar, Milan

2017-01-01

A new high-sensitivity potentiometric sensor for anionic surfactants was fabricated using the dimethyldioctadecylammonium-tetraphenylborate (DDA-TPB) ion associate as an ionophore that was incorporated into a liquid PVC membrane. Carbon powder was used for immobilization of the ionophore in the membrane, thus significantly reducing its ohmic resistance and reducing its signal drift. The sensor exhibits a sub-Nernstian response for both dodecylbenzenesulfonate (DBS) and dodecyl sulfate (DS) in H 2 O (55.3 and 58.5mV/decade of activity, respectively) in a range between 3.2×10 -7 and 4.6×10 -3 M for DS and 2.5×10 -7 and 1.2×10 -3 M for DBS. The sensor also exhibited a sub-Nernstian response for DS and DBS in 10mM Na 2 SO 4 (55.4 and 57.7mV/decade of activity, respectively) between 2.5×10 -7 and 4.6×10 -3 M for DS and 1.5×10 -7 and 8.8×10 -4 M for DBS. The detection limits for DS and DBS in H 2 O were 2.5×10 -7 and 2.0×10 -7 M and in 10mM Na 2 SO 4 the detection limits were 2.5×10 -7 and 1.2×10 -7 M, respectively. The response time of the sensor was less than 5s for changes at higher concentration levels (above 1×10 -4 M) in both water and 10mM Na 2 SO 4. At lower concentrations (below 1×10 -5 M) the response times were 8 and 6s in water and 10mM Na 2 SO 4 , respectively. The signal drift of the sensor was 1.2mV/hour. The new carbon-based sensor exhibited excellent selectivity performance for DS over almost all of the anions commonly present in commercial formulations and it was successfully employed as an end-point detector in potentiometric titrations of anionic surfactants in a pH range from 3 to 12. Three-component mixtures containing sodium alkanesulfonate (C 10 , C 12 and C 14 ) were successfully differentially titrated. Copyright © 2016 Elsevier B.V. All rights reserved.

Production of interferon-¿ and interleukin-4 by human T cells recognizing Leishmania lipophosphoglycan-associated protein

DEFF Research Database (Denmark)

Kemp, M; Kurtzhals, J A; Christensen, C B

1993-01-01

The Leishmania protein LPGAP which is co-isolated with lipophosphoglycan is a specific activator of T cells from individuals who have recovered from American leishmaniasis. We have tested the effect of LPGAP on peripheral blood mononuclear cells (PBMC) from Kenyan donors cured from L. donovani in....... The results show that both IFN-gamma producing (Th1-like) and IL-4 producing (Th2-like) T cells recognizing LPGAP are expanded after infection with L. donovani in humans....... infections. LPGAP induced vigorous proliferation and production of interferon-gamma (IFN-gamma) by the cells. In addition PBMC incubated with LPGAP released interleukin-4 (IL-4) after pulsing with ionomycin and phorbol myristate acetate. Single cells were isolated from LPGAP-stimulated cell lines...

Regulation of human renin expression in chorion cell primary cultures

International Nuclear Information System (INIS)

Duncan, K.G.; Haidar, M.A.; Baxter, J.D.; Reudelhuber, T.L.

1990-01-01

The human renin gene is expressed in the kidney, placenta, and several other sites. The release of renin or its precursor, prorenin, can be affected by several regulatory agents. In this study, primary cultures of human placental cells were used to examine the regulation of prorenin release and renin mRNA levels and of the transfected human renin promoter linked to chloramphenicol acetyltransferase reporter sequences. Treatment of the cultures with a calcium ionophore alone, calcium ionophore plus forskolin (that activates adenylate cyclase), or forskolin plus a phorbol ester increased prorenin release and renin mRNA levels 1.3 endash to 6 endash fold, but several classes of steroids did not affect prorenin secretion or renin RNA levels. These results suggest that (i) the first 584 base pairs of the renin gene 5'endash flanking DNA do not contain functional glucocorticoid or estrogen response elements, (ii) placental prorenin release and renin mRNA are regulated by calcium ion and by the combinations of cAMP with either C kinase or calcium ion, and (iii) the first 100 base pairs of the human renin 5'endash flanking DNA direct accurate initiation of transcription and can be regulated by cAMP. Thus, some control of renin release in the placenta (and by inference in other tissues) occurs via transcriptional influences on its promoter

Papillon-Lefèvre syndrome patient reveals species-dependent requirements for neutrophil defenses

DEFF Research Database (Denmark)

Sørensen, Ole E.; Clemmensen, Stine N; Dahl, Sara L

2014-01-01

immunodeficiency. Here, we characterized a 24-year-old woman who had suffered from severe juvenile periodontal disease, but was otherwise healthy, and identified a homozygous missense mutation in CTSC indicative of PLS. Proteome analysis of patient neutrophil granules revealed that several proteins that normally......Papillon-Lefèvre syndrome (PLS) results from mutations that inactivate cysteine protease cathepsin C (CTSC), which processes a variety of serine proteases considered essential for antimicrobial defense. Despite serine protease-deficient immune cell populations, PLS patients do not exhibit marked......CAP-18 into the antibacterial peptide LL-37 in response to ionomycin. In immature myeloid cells from patient bone marrow, biosynthesis of CTSC and neutrophil serine proteases appeared normal along with initial processing and sorting to cellular storage. In contrast, these proteins were completely absent...

Protein import into chloroplasts requires a chloroplast ATPase

International Nuclear Information System (INIS)

Pain, D.; Blobel, G.

1987-01-01

The authors have transcribed mRNA from a cDNA clone coding for pea ribulose-1,5-bisphosphate carboxylase, translated the mRNA in a wheat germ cell-free system, and studied the energy requirement for posttranslational import of the [ 35 S]methionine-labeled protein into the stroma of pea chloroplasts. They found that import depends on ATP hydrolysis within the stroma. Import is not inhibited when H + , K + , Na + , or divalent cation gradients across the chloroplast membranes are dissipated by ionophores, as long as exogenously added ATP is also present during the import reaction. The data suggest that protein import into the chloroplast stroma requires a chloroplast ATPase that does not function to generate a membrane potential for driving the import reaction but that exerts its effect in another, yet-to-be-determined, mode. They have carried out a preliminary characterization of this ATPase regarding its nucleotide specificity and the effects of various ATPase inhibitors

Protein import into chloroplasts requires a chloroplast ATPase

Energy Technology Data Exchange (ETDEWEB)

Pain, D.; Blobel, G.

1987-05-01

The authors have transcribed mRNA from a cDNA clone coding for pea ribulose-1,5-bisphosphate carboxylase, translated the mRNA in a wheat germ cell-free system, and studied the energy requirement for posttranslational import of the (/sup 35/S)methionine-labeled protein into the stroma of pea chloroplasts. They found that import depends on ATP hydrolysis within the stroma. Import is not inhibited when H/sup +/, K/sup +/, Na/sup +/, or divalent cation gradients across the chloroplast membranes are dissipated by ionophores, as long as exogenously added ATP is also present during the import reaction. The data suggest that protein import into the chloroplast stroma requires a chloroplast ATPase that does not function to generate a membrane potential for driving the import reaction but that exerts its effect in another, yet-to-be-determined, mode. They have carried out a preliminary characterization of this ATPase regarding its nucleotide specificity and the effects of various ATPase inhibitors.

Impact of salinomycin on the intestinal microflora of broiler chickens

DEFF Research Database (Denmark)

Johansen, Charlotte; Friis-Holm, Lotte Bjerrum; Pedersen, Karl

2007-01-01

jejuni infection and on the composition of the caecal microflora in broiler chickens. Methods: An experimental infection study was carried out in isolators and the intestinal microflora was analyzed using quantitative cultivation, denaturant gradient gel electrophoresis (DGGE), cloning and sequencing...... treated chickens compared to un-treated controls. Conclusion: Termination of the use of ionophore coccidiostats will not affect food safety related to campylobacter, but will increase the risk of necrotic enteritis in the broilers....

Tetraazacyclohexadeca Macrocyclic Ligand as a Neutral Carrier in a Cr Ion-selective Electrode

Directory of Open Access Journals (Sweden)

Puja Saxena

2004-12-01

Full Text Available Abstract: A polystyrene-based membrane of 2,10-dimethyl-4,12-diphenyl-1,5,9,13-tetraazacyclohexadeca-1,4,9,12-tetraene macrocyclic ionophore was prepared and investigated as Cr(III-selective electrode. The best performance was observed with the membrane having the polystyrene-ligand-dibutylphthalate-sodiumtetraphenyl borate composition 1:4:1:1 with a Nernstian slope of 19.0 mV per decade of concentration between pH 3.0 and 6.5. This electrode has been found to be chemically inert and of adequate stability with a response time of 20 s and was used over a period of 100 d with good reproducibility (S= 0.3 mV. The membrane works satisfactorily in a partially non-aqueous medium up to a maximum 30% (v/v content of methanol and ethanol. The potentiometric selectivity coefficient values indicate that the membrane sensor is highly selective for Cr(III ions over a number of monovalent, divalent and trivalent cations. The membrane electrode has also been successfully used to determine Cr3+ in various food materials.

Flow Injection Potentiometric Determination of Cd2+ Ions Using a Coated Graphite Plasticized PVC-Membrane Electrode Based on 1, 3-Bis(2-cyanobenzene)triazene.

Science.gov (United States)

Shamsipur, Mojtaba; Sahari, Shokat; Payehghadr, Mahmood; Alizadeh, Kamal

2011-09-01

1, 3-Bis(2-cyanobenzene)triazene, L, was used as a suitable ionophore for the fabrication of a new PVC-based polymeric membrane coated graphite electrode for selective sensing of Cd2+ ion. The electrode exhibited a selective linear Nernstian response to Cd2+ ion at an optimal pH range of 6-9 with a limit of detection of 8.0 × 10-6 M and a fast response time of about 2 s. The electrode was used as a proper detection system in flow-injection potentiometry of cadmium ion and resulted in well defined peaks for cadmium ions with stable baseline, excellent reproducibility and high sampling rates of over 100 injections per hour. It showed good stability, reproducibility and fast response time. The practical utility of the proposed system has also been reported.