WorldWideScience

Sample records for cholesterol oxidase interference

  1. Expression and comparison of recombinant cholesterol oxidases ...

    African Journals Online (AJOL)

    The structure and bio-activity of an endogenous cholesterol oxidase from Brevibacterium sp. was compared to the same enzyme exogenously expressed in Escherichia coli BL21 (DE3) with and without N- or C-terminal his-tags. The different proteins were purified with affinity and subtractive protocols. The specific activity of ...

  2. Implementation of cellulomonas cholesterol oxidase for total serum cholesterol determination by the endpoint method.

    Science.gov (United States)

    Srisawasdi, Pornpen; Chaichanajarernkul, Upsorn; Teerakranjana, Narumon; Kroll, Martin H

    2008-01-01

    Cellulomonas has been shown to be a good source of cholesterol oxidase in addition to Streptomyces for serum cholesterol determination by the endpoint method, inexpensive in cost, and showing excellent performance. For clinical use, we have assessed the reliability of Cellulomonas reagent for cholesterol determination. We constructed the user-defined endpoint methods on three automated analyzers. The analytical performances (linearity, precision, recovery, interference, stability, and comparison with the standardized method) of Cellulomonas cholesterol reagents were evaluated and compared to those of Streptomyces reagents. Linearity (18.1-23.3 mmol/L) and stability of reagents (6-11 weeks) depended on the analyzers being used. The average within-run and between-day % coefficients of variation (CVs) ranged from 1.44 to 2.45 and 1.98 to 2.99, respectively, and were within National Cholesterol Education Program analytical criteria (Cellulomonas enzyme is analytically reliable when used for serum cholesterol determination by the endpoint method. Its analytical performance is equivalent to Streptomyces enzymes and meets the analytical goals. It has an advantage over the other enzymes in that it does not ship in the frozen state. (c) 2008 Wiley-Liss, Inc.

  3. Application of Streptomyces and Brevibacterium cholesterol oxidase for total serum cholesterol assay by the enzymatic kinetic method.

    Science.gov (United States)

    Srisawasdi, Pornpen; Jearanaikoon, Patcharee; Wetprasit, Nuanchawee; Sriwanthana, Busarawan; Kroll, Martin H; Lolekha, Porntip H

    2006-10-01

    Using non-esterified cholesterol standard, Brevibacterium and Streptomyces are found as suitable sources of cholesterol oxidase for kinetic cholesterol assay. For clinical use, we investigated the suitability of these enzymes for cholesterol determination in human serum. We compared the performance of reagents containing 2 enzymes for the kinetic determination of total serum cholesterol with the standardized endpoint method. Reagent containing Streptomyces enzyme was more sensitive than that of Brevibacterium, with linearity up to 20.7 and 2.6 mmol/l, respectively. The analytical reaction for Streptomyces showed a shorter lag phase (148 s) and a steeper slope (absorbance vs. time) than that of Brevibacterium (246 s). The assay using Streptomyces reagent was precise and accurate and compared favorably with the endpoint method (y=1.06x-0.15, r=0.996, bias=0.21 mmol/l). Hemoglobin as high as 7.5 g/l did not interfere while turbidity greater than 2+ (absorbance >0.778 at 670 nm) and bilirubin concentrations >171.0 micromol/l did interfere (in a negative interference). Reagent was stable up to at least 8 weeks. The Streptomyces cholesterol oxidase, with 3,4-dichlorophenol, proved a suitable source for serum total cholesterol determination by the kinetic method.

  4. Amperometric determination of serum total cholesterol with nanoparticles of cholesterol esterase and cholesterol oxidase.

    Science.gov (United States)

    Aggarwal, V; Malik, J; Prashant, A; Jaiwal, P K; Pundir, C S

    2016-05-01

    We describe the preparation of glutaraldehyde cross-linked and functionalized cholesterol esterase nanoparticles (ChENPs) and cholesterol oxidase nanoparticles (ChOxNPs) aggregates and their co-immobilization onto Au electrode for improved amperometric determination of serum total cholesterol. Transmission electron microscope (TEM) images of ChENPs and ChOxNPs showed their spherical shape and average size of 35.40 and 56.97 nm, respectively. Scanning electron microscope (SEM) studies of Au electrode confirmed the co-immobilization of enzyme nanoparticles (ENPs). The biosensor exhibited optimal response at pH 5.5 and 40°C within 5 s when polarized at +0.25 V versus Ag/AgCl. The working/linear range of the biosensor was 10-700 mg/dl for cholesterol. The sensor showed high sensitivity and measured total cholesterol as low as 0.1 mg/dl. The biosensor was evaluated and employed for total cholesterol determination in sera of apparently healthy and diseased persons. The analytical recovery of added cholesterol was 90%, whereas the within-batch and between-batch coefficients of variation (CVs) were less than 2% and less than 3%. There was a good correlation (r = 0.99) between serum cholesterol values as measured by the standard enzymic colorimetric method and the current method. The initial activity of ENPs/working electrode was reduced by 50% during its regular use (200 times) over a period of 60 days when stored dry at 4°C. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Optimization of cholesterol oxidase production by Brevibacterium sp ...

    African Journals Online (AJOL)

    Abstract. An ultrasound-assisted emulsification as a pretreatment for cholesterol oxidase production by submerge fermentation using Brevibacterium sp. in a batch system was studied. Medium improvement for the production employing response surface methodology (RSM) was optimized in this paper. The concentration of ...

  6. The ultrasonic effect on the mechanism of cholesterol oxidase ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-04-26

    Apr 26, 2010 ... The effects of ultrasonic radiation on cholesterol oxidase production by Brevibacterium sp. are studied in this paper. An ultrasonic wave with low intensity at 20 kHz, 200 W/ cm2 was employed to study the effects of irradiation at different lengths of time on the growth of Brevibacterium sp. cells. The result.

  7. Fabricating an Amperometric Cholesterol Biosensor by a Covalent Linkage between Poly(3-thiopheneacetic acid and Cholesterol Oxidase

    Directory of Open Access Journals (Sweden)

    Kuo-Chuan Ho

    2009-03-01

    Full Text Available In this study, use of the covalent enzyme immobilization method was proposed to attach cholesterol oxidase (ChO on a conducting polymer, poly(3-thiopheneacetic acid, [poly(3-TPAA]. Three red-orange poly(3-TPAA films, named electrodes A, B and C, were electropolymerized on a platinum electrode by applying a constant current of 1.5 mA, for 5, 20 and 100 s, respectively. Further, 1-ethyl-3-(3-dimethylamiopropylcarbodiimide hydrochloride (EDC‧HCl and N-hydroxysuccinimide (NHS were used to activate the free carboxylic groups of the conducting polymer. Afterwards, the amino groups of the cholesterol oxidase were linked on the activated groups to form peptide bonds. The best sensitivity obtained for electrode B is 4.49 mA M-1 cm-2,with a linear concentration ranging from 0 to 8 mM, which is suitable for the analysis of cholesterol in humans. The response time (t95 is between 70 and 90 s and the limit of detection is 0.42 mM, based on the signal to noise ratio equal to 3. The interference of species such as ascorbic acid and uric acid increased to 5.2 and 10.3% of the original current response, respectively, based on the current response of cholesterol (100%. With respect to the long-term stability, the sensing response retains 88% of the original current after 13 days.

  8. An amperometric cholesterol biosensor based on epoxy resin membrane bound cholesterol oxidase.

    Science.gov (United States)

    Pundir, C S; Narang, Jagriti; Chauhan, Nidhi; Sharma, Preety; Sharma, Renu

    2012-10-01

    The use of epoxy resin membrane as a support for immobilization of enzyme has resulted into improved sensitivity and stability of biosensors for uric acid, ascorbic acid and polyphenols. The present work was aimed to prepare an improved amperometric biosensor for determination of serum cholesterol required in the diagnostics and management of certain pathological conditions. Epoxy resin membrane with immobilized cholesterol oxidase was mounted on the cleaned platinum (Pt) electrode with a parafilm to construct a working electrode. This working electrode along with Ag/AgCl as reference and Ag wire as an auxiliary electrode were connected through a three terminal electrometer to construct a cholesterol biosensor. The sensor showed optimum response within 25 sec at pH 7.0 and 45°C. The linear working range of biosensor was 1.0 to 8.0 mM cholesterol. K m and I max for cholesterol were 5.0 mM and 9.09 μA, respectively. The biosensor measured serum cholesterol. The minimum detection limit of the sensor was 1.0 mM. The mean analytical recoveries of added cholesterol in serum (2.84 and 4.13 mM) were 91.4 ± 2.8 and 92.3 ± 3.1 per cent (n=6), respectively. Within and between assay coefficient of variation (CV) were epoxy resin membrane as a support for immobilization of cholesterol oxidase has resulted into an improved amperometric cholesterol biosensor. The present biosensor had an advantage over the existing biosensors as it worked at comparatively lower potential.

  9. Preparation of cholesterol oxidase nanoparticles and their application in amperometric determination of cholesterol

    Science.gov (United States)

    Chawla, Sheetal; Rawal, Rachna; Sonia; Ramrati; Pundir, C. S.

    2013-09-01

    The nanoparticle (NP) aggregates of commercial cholesterol oxidase (ChOx) were prepared by desolvation method. The formation and characterization of ChOxNP aggregates were studied by transmission electron microscopy and scanning electron microscopy. NP aggregates were more stable, active and had a higher shelf life than that of free enzyme. An amperometric cholesterol biosensor was constructed by immobilizing ChOxNPs onto Au electrode. The biosensor showed optimum response within 8 s at pH 6.0 and 35 °C, when polarized at +0.27 V versus Ag/AgCl. The biosensor possesses high sensitivity and measures cholesterol concentrations as low as 1.56 mg/dl. The working linear range was 12.5-700 mg/dl for cholesterol. The biosensor was evaluated and employed for measurement of total cholesterol in human serum. The enzyme electrode lost 50 % of its initial activity during its regular use for 180 times over a period of 90 days when stored in 0.1 M sodium phosphate buffer, pH 7.0 at 4 °C.

  10. Preparation of cholesterol oxidase nanoparticles and their application in amperometric determination of cholesterol

    Energy Technology Data Exchange (ETDEWEB)

    Chawla, Sheetal; Rawal, Rachna; Sonia; Ramrati; Pundir, C. S., E-mail: pundircs@rediffmail.com [M. D. University, Department of Biochemistry (India)

    2013-09-15

    The nanoparticle (NP) aggregates of commercial cholesterol oxidase (ChOx) were prepared by desolvation method. The formation and characterization of ChOxNP aggregates were studied by transmission electron microscopy and scanning electron microscopy. NP aggregates were more stable, active and had a higher shelf life than that of free enzyme. An amperometric cholesterol biosensor was constructed by immobilizing ChOxNPs onto Au electrode. The biosensor showed optimum response within 8 s at pH 6.0 and 35 Degree-Sign C, when polarized at +0.27 V versus Ag/AgCl. The biosensor possesses high sensitivity and measures cholesterol concentrations as low as 1.56 mg/dl. The working linear range was 12.5-700 mg/dl for cholesterol. The biosensor was evaluated and employed for measurement of total cholesterol in human serum. The enzyme electrode lost 50 % of its initial activity during its regular use for 180 times over a period of 90 days when stored in 0.1 M sodium phosphate buffer, pH 7.0 at 4 Degree-Sign C.

  11. Lipid-based transfection reagents can interfere with cholesterol biosynthesis.

    Science.gov (United States)

    Danielli, Mauro; Marinelli, Raúl A

    2016-02-15

    Lipid-based transfection reagents are widely used for delivery of small interfering RNA into cells. We examined whether the commonly used commercial transfection reagents DharmaFECT-4 and Lipofectamine 2000 can interfere with lipid metabolism by studying cholesterogenesis. Cholesterol de novo synthesis from [(14)C]acetate was assessed in human hepatocyte-derived Huh-7 cells. The results revealed that DharmaFECT, but not Lipofectamine, markedly inhibited cholesterol biosynthesis by approximately 70%. Cell viability was not significantly altered. These findings suggest that caution is required in the choice of certain lipid-based transfection reagents for gene silencing experiments, particularly when assessing cholesterol metabolism. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Cholesterol oxidase with high catalytic activity from Pseudomonas aeruginosa: Screening, molecular genetic analysis, expression and characterization.

    Science.gov (United States)

    Doukyu, Noriyuki; Nihei, Shyou

    2015-07-01

    An extracellular cholesterol oxidase producer, Pseudomonas aeruginosa strain PA157, was isolated by a screening method to detect 6β-hydroperoxycholest-4-en-3-one-forming cholesterol oxidase. On the basis of a putative cholesterol oxidase gene sequence in the genome sequence data of P. aeruginosa strain PAO1, the cholesterol oxidase gene from strain PA157 was cloned. The mature form of the enzyme was overexpressed in Escherichia coli cells. The overexpressed enzyme formed inclusion bodies in recombinant E. coli cells grown at 20 °C and 30 °C. A soluble and active PA157 enzyme was obtained when the recombinant cells were grown at 10 °C. The purified enzyme was stable at pH 5.5 to 10 and was most active at pH 7.5-8.0, showing optimal activity at pH 7.0 and 70 °C. The enzyme retained about 90% of its activity after incubation for 30 min at 70 °C. The enzyme oxidized 3β-hydroxysteroids such as cholesterol, β-cholestanol, and β-sitosterol at high rates. The Km value and Vmax value for the cholesterol were 92.6 μM and 15.9 μmol/min/mg of protein, respectively. The Vmax value of the enzyme was higher than those of commercially available cholesterol oxidases. This is the first report to characterize a cholesterol oxidase from P. aeruginosa. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  13. Cholesterol: A modulator of the phagocyte NADPH oxidase activity - A cell-free study

    Directory of Open Access Journals (Sweden)

    Rawand Masoud

    2014-01-01

    Full Text Available The NADPH oxidase Nox2, a multi-subunit enzyme complex comprising membrane and cytosolic proteins, catalyzes a very intense production of superoxide ions O2•−, which are transformed into other reactive oxygen species (ROS. In vitro, it has to be activated by addition of amphiphiles like arachidonic acid (AA. It has been shown that the membrane part of phagocyte NADPH oxidase is present in lipid rafts rich in cholesterol. Cholesterol plays a significant role in the development of cardio-vascular diseases that are always accompanied by oxidative stress. Our aim was to investigate the influence of cholesterol on the activation process of NADPH oxidase. Our results clearly show that, in a cell-free system, cholesterol is not an efficient activator of NADPH oxidase like arachidonic acid (AA, however it triggers a basal low superoxide production at concentrations similar to what found in neutrophile. A higher concentration, if present during the assembly process of the enzyme, has an inhibitory role on the production of O2•−. Added cholesterol acts on both cytosolic and membrane components, leading to imperfect assembly and decreasing the affinity of cytosolic subunits to the membrane ones. Added to the cytosolic proteins, it retains their conformations but still allows some conformational change induced by AA addition, indispensable to activation of NADPH oxidase.

  14. Coenzyme precursor-assisted expression of a cholesterol oxidase from Brevibacterium sp. in Escherichia coli.

    Science.gov (United States)

    Wang, Longgang; Wang, Wu

    2007-05-01

    The gene (choB(b)), encoding cholesterol oxidase from Brevibacterium sp. CCTCC M201008, was cloned and sequenced by PCR (GenBank accession number: DQ345780). The gene consists of 1653 base pairs and encodes a protein of 551 amino acids. ChoB(b) exhibited a homology of 98% with cholesterol oxidase gene from Brevibacterium sterolicum ATCC 21387. The cholesterol oxidase gene, cloned in the vector pET-28a, was over-expressed in Escherichia coli BL21-CodonPlus (DE3)-RP grown at 23 degrees C in Luria-Bertani medium containing 50 microM riboflavin, the precursor of the FAD coenzyme of the enzyme. A maximum activity of 3.7 U/mg was obtained from cell free extract of E. coli BL21-CodonPlus (DE3)-RP harboring the pET-28a-choB(b).

  15. Production of recombinant cholesterol oxidase containing covalently bound FAD in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Molla Gianluca

    2010-04-01

    Full Text Available Abstract Background Cholesterol oxidase is an alcohol dehydrogenase/oxidase flavoprotein that catalyzes the dehydrogenation of C(3-OH of cholesterol. It has two major biotechnological applications, i.e. in the determination of serum (and food cholesterol levels and as biocatalyst providing valuable intermediates for industrial steroid drug production. Cholesterol oxidases of type I are those containing the FAD cofactor tightly but not covalently bound to the protein moiety, whereas type II members contain covalently bound FAD. This is the first report on the over-expression in Escherichia coli of type II cholesterol oxidase from Brevibacterium sterolicum (BCO. Results Design of the plasmid construct encoding the mature BCO, optimization of medium composition and identification of the best cultivation/induction conditions for growing and expressing the active protein in recombinant E. coli cells, concurred to achieve a valuable improvement: BCO volumetric productivity was increased from ~500 up to ~25000 U/L and its crude extract specific activity from 0.5 up to 7.0 U/mg protein. Interestingly, under optimal expression conditions, nearly 55% of the soluble recombinant BCO is produced as covalently FAD bound form, whereas the protein containing non-covalently bound FAD is preferentially accumulated in insoluble inclusion bodies. Conclusions Comparison of our results with those published on non-covalent (type I COs expressed in recombinant form (either in E. coli or Streptomyces spp., shows that the fully active type II BCO can be produced in E. coli at valuable expression levels. The improved over-production of the FAD-bound cholesterol oxidase will support its development as a novel biotool to be exploited in biotechnological applications.

  16. Preparation and some properties of cholesterol oxidase from Rhodococcus sp. R14-2

    NARCIS (Netherlands)

    Wang, C.T.; Cao, Y.P.; Sun, B.G.; Ji, B.P.; Nout, M.J.R.; Wang, J.; Zhao, Y.H.

    2008-01-01

    Rhodococcus sp. R14-2, isolated from Chinese Jin-hua ham, produces a novel extracellular cholesterol oxidase (COX). The enzyme was extracted from fermentation broth and purified 53.1-fold based on specific activity. The purified enzyme shows a single polypeptide band on SDS-PAGE with an estimated

  17. Gold Nanoparticles Like A Matrix For Covalent Immobilization Of Cholesterol Oxidase – Application For Biosensing

    Directory of Open Access Journals (Sweden)

    Wojnarowska R.

    2015-09-01

    Full Text Available Gold nanoparticles are emerging as promising agents for various areas of material science as well as nanotechnology, electronics and medicine. The interest in this material is provided due to its unique optical, electronic and molecular-recognition properties. This paper presents results of preparation, characterization and biofunctionalization of gold nanoparticles. Nanoparticles have been conjugated with the cholesterol oxidase enzyme in order to prepare the active element for biosensors. Cholesterol oxidase is one of the most important analytical enzyme, used for cholesterol assay in clinical diagnostics, and there is still a necessity in improvement of existing analytical techniques, including bio-nanotechnological approaches based on modern nanosystems. The prepared bio-nanosystem was characterized by the enzyme activity test. Obtained results showed a stable binding of the enzyme with nanoparticles and preserved the bioactivity approves which gives possibility to use the prepared bio-nanosystems for analytical purposes.

  18. Microprojectile Bombardment Transformation of Date Palm Using the Insecticidal Cholesterol Oxidase (ChoA) Gene.

    Science.gov (United States)

    Allam, Mai A; Saker, Mahmoud M

    2017-01-01

    The overall objective of this work is to optimize the transformation system for date palm as a first step toward production of date palm clones resistant to noxious pests. A construct harboring the cholesterol oxidase (ChoA) gene, which renders plant resistance against insect attack, is introduced into embryogenic date palm callus using the PDS-1000/He particle bombardment system. The process involves the establishment of embryogenic callus cultures as well as immature embryo-derived microcalli that are used as target tissues for shooting and optimization of transformation conditions. This chapter in addition explains molecular and histochemical assays conducted to confirm gene integration and expression.

  19. On the oxygen reactivity of flavoprotein oxidases: an oxygen access tunnel and gate in brevibacterium sterolicum cholesterol oxidase.

    Science.gov (United States)

    Piubelli, Luciano; Pedotti, Mattia; Molla, Gianluca; Feindler-Boeckh, Susanne; Ghisla, Sandro; Pilone, Mirella S; Pollegioni, Loredano

    2008-09-05

    The flavoprotein cholesterol oxidase from Brevibacterium sterolicum (BCO) possesses a narrow channel that links the active center containing the flavin to the outside solvent. This channel has been proposed to serve for the access of dioxygen; it contains at its "bottom" a Glu-Arg pair (Glu-475-Arg-477) that was found by crystallographic studies to exist in two forms named "open" and "closed," which in turn was suggested to constitute a gate functioning in the control of oxygen access. Most mutations of residues that flank the channel have minor effects on the oxygen reactivity. Mutations of Glu-311, however, cause a switch in the basic kinetic mechanism of the reaction of reduced BCO with dioxygen; wild-type BCO and most mutants show a saturation behavior with increasing oxygen concentration, whereas for Glu-311 mutants a linear dependence is found that is assumed to reflect a "simple" second order process. This is taken as support for the assumption that residue Glu-311 finely tunes the Glu-475-Arg-477 pair, forming a gate that functions in modulating the access/reactivity of dioxygen.

  20. Artificial Intelligence versus Statistical Modeling and Optimization of Cholesterol Oxidase Production by using Streptomyces Sp.

    Science.gov (United States)

    Pathak, Lakshmi; Singh, Vineeta; Niwas, Ram; Osama, Khwaja; Khan, Saif; Haque, Shafiul; Tripathi, C K M; Mishra, B N

    2015-01-01

    Cholesterol oxidase (COD) is a bi-functional FAD-containing oxidoreductase which catalyzes the oxidation of cholesterol into 4-cholesten-3-one. The wider biological functions and clinical applications of COD have urged the screening, isolation and characterization of newer microbes from diverse habitats as a source of COD and optimization and over-production of COD for various uses. The practicability of statistical/ artificial intelligence techniques, such as response surface methodology (RSM), artificial neural network (ANN) and genetic algorithm (GA) have been tested to optimize the medium composition for the production of COD from novel strain Streptomyces sp. NCIM 5500. All experiments were performed according to the five factor central composite design (CCD) and the generated data was analysed using RSM and ANN. GA was employed to optimize the models generated by RSM and ANN. Based upon the predicted COD concentration, the model developed with ANN was found to be superior to the model developed with RSM. The RSM-GA approach predicted maximum of 6.283 U/mL COD production, whereas the ANN-GA approach predicted a maximum of 9.93 U/mL COD concentration. The optimum concentrations of the medium variables predicted through ANN-GA approach were: 1.431 g/50 mL soybean, 1.389 g/50 mL maltose, 0.029 g/50 mL MgSO4, 0.45 g/50 mL NaCl and 2.235 ml/50 mL glycerol. The experimental COD concentration was concurrent with the GA predicted yield and led to 9.75 U/mL COD production, which was nearly two times higher than the yield (4.2 U/mL) obtained with the un-optimized medium. This is the very first time we are reporting the statistical versus artificial intelligence based modeling and optimization of COD production by Streptomyces sp. NCIM 5500.

  1. Cholesterol Oxidase Binds TLR2 and Modulates Functional Responses of Human Macrophages

    Directory of Open Access Journals (Sweden)

    Katarzyna Bednarska

    2014-01-01

    Full Text Available Cholesterol oxidase (ChoD is considered to be an important virulence factor for Mycobacterium tuberculosis (Mtb, but its influence on macrophage activity is unknown. Here we used Nocardia erythropolis ChoD, which is very similar to the Mtb enzyme (70% identity at the amino-acid level, to evaluate the impact of bacterial ChoD on the activity of THP-1-derived macrophages in vitro. We found that ChoD decreased the surface expression of Toll-like receptor type 2 (TLR2 and complement receptor 3 (CR3 on these macrophages. Flow cytometry and confocal microscopy showed that ChoD competed with lipoteichoic acid for ligand binding sites on TLR2 but not on CR3, suggesting that ChoD signaling is mediated via TLR2. Binding of ChoD to the membrane of macrophages had diverse effects on the activity of macrophages, activating p38 mitogen activated kinase and stimulating production of a large amount of interleukin-10. Moreover, ChoD primed macrophages to enhance the production of reactive oxygen species in response to the phorbol myristate acetate, which was reduced by “switching off” TLR-derived signaling through interleukin-1 receptor-associated kinases 1 and 4 inhibition. Our study revealed that ChoD interacts directly with macrophages via TLR2 and influences the biological activity of macrophages during the development of the initial response to infection.

  2. Artificial Intelligence versus Statistical Modeling and Optimization of Cholesterol Oxidase Production by using Streptomyces Sp.

    Directory of Open Access Journals (Sweden)

    Lakshmi Pathak

    Full Text Available Cholesterol oxidase (COD is a bi-functional FAD-containing oxidoreductase which catalyzes the oxidation of cholesterol into 4-cholesten-3-one. The wider biological functions and clinical applications of COD have urged the screening, isolation and characterization of newer microbes from diverse habitats as a source of COD and optimization and over-production of COD for various uses. The practicability of statistical/ artificial intelligence techniques, such as response surface methodology (RSM, artificial neural network (ANN and genetic algorithm (GA have been tested to optimize the medium composition for the production of COD from novel strain Streptomyces sp. NCIM 5500. All experiments were performed according to the five factor central composite design (CCD and the generated data was analysed using RSM and ANN. GA was employed to optimize the models generated by RSM and ANN. Based upon the predicted COD concentration, the model developed with ANN was found to be superior to the model developed with RSM. The RSM-GA approach predicted maximum of 6.283 U/mL COD production, whereas the ANN-GA approach predicted a maximum of 9.93 U/mL COD concentration. The optimum concentrations of the medium variables predicted through ANN-GA approach were: 1.431 g/50 mL soybean, 1.389 g/50 mL maltose, 0.029 g/50 mL MgSO4, 0.45 g/50 mL NaCl and 2.235 ml/50 mL glycerol. The experimental COD concentration was concurrent with the GA predicted yield and led to 9.75 U/mL COD production, which was nearly two times higher than the yield (4.2 U/mL obtained with the un-optimized medium. This is the very first time we are reporting the statistical versus artificial intelligence based modeling and optimization of COD production by Streptomyces sp. NCIM 5500.

  3. Bioconjugation of lipase and cholesterol oxidase with graphene or graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rubens A.; Souza, Michele L.; Bloisi, Georgia D.; Corio, Paolo; Petri, Denise F. S., E-mail: dfsp@iq.usp.br [Universidade de São Paulo, Instituto de Química (Brazil)

    2015-04-15

    The catalytic behavior of lipase and cholesterol oxidase (ChOx) in the absence and in the presence of graphene (G) or graphene oxide (GO) was investigated at 24 ± 1 °C and pH 6.5. GO flat sheets (0.5–2 μm) were ∼2-nm thick, while G formed aggregates. The maximum reaction velocity (V{sub max}) values and turnover numbers (k{sub cat}) determined for reactions catalyzed by physical mixtures of lipase (at 0.01 g l{sup −1}) or ChOx (at 0.03 g l{sup −1}) and G (0.012 g l{sup −1}) increased six-fold or doubled, respectively, in comparison to neat enzymes. Circular dichroism (CD) and photoluminescence (PL) spectroscopic measurements revealed the preservation of native secondary structures of enzymes and bioconjugation driven by hydrophobic interaction and energy transfer (redshift) between lipase or ChOx and G, corroborating with the enhanced catalytic behavior. On the other hand, the interactions between GO, which has hydrophilic moieties on the basal plane, and ChOx caused enzyme deactivation, as evidenced by the absence of typical CD signal. At low GO concentration (<0.012 g l{sup −1}), bioconjugates of lipases with GO led to V{sub max} and k{sub cat} values four-fold lower than their counterparts with G, but the GO hydrophilic groups probably favored the affinity for the substrate, because the Michaelis constant (K{sub m}) values decreased in comparison to that of neat lipase. Upon increasing the GO concentration, lipases lost secondary structure and the typical lipase PL bands disappeared.

  4. When cholesterol is not cholesterol: a note on the enzymatic determination of its concentration in model systems containing vegetable extracts

    Directory of Open Access Journals (Sweden)

    Pamplona Reinald

    2010-06-01

    Full Text Available Abstract Background Experimental evidences demonstrate that vegetable derived extracts inhibit cholesterol absorption in the gastrointestinal tract. To further explore the mechanisms behind, we modeled duodenal contents with several vegetable extracts. Results By employing a widely used cholesterol quantification method based on a cholesterol oxidase-peroxidase coupled reaction we analyzed the effects on cholesterol partition. Evidenced interferences were analyzed by studying specific and unspecific inhibitors of cholesterol oxidase-peroxidase coupled reaction. Cholesterol was also quantified by LC/MS. We found a significant interference of diverse (cocoa and tea-derived extracts over this method. The interference was strongly dependent on model matrix: while as in phosphate buffered saline, the development of unspecific fluorescence was inhibitable by catalase (but not by heat denaturation, suggesting vegetable extract derived H2O2 production, in bile-containing model systems, this interference also comprised cholesterol-oxidase inhibition. Several strategies, such as cholesterol standard addition and use of suitable blanks containing vegetable extracts were tested. When those failed, the use of a mass-spectrometry based chromatographic assay allowed quantification of cholesterol in models of duodenal contents in the presence of vegetable extracts. Conclusions We propose that the use of cholesterol-oxidase and/or peroxidase based systems for cholesterol analyses in foodstuffs should be accurately monitored, as important interferences in all the components of the enzymatic chain were evident. The use of adequate controls, standard addition and finally, chromatographic analyses solve these issues.

  5. Immobilization of cholesterol oxidase on magnetic fluorescent core-shell-structured nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jun, E-mail: hjun@whut.edu.cn; Liu, Huichao; Zhang, Peipei; Zhang, Pengfei; Li, Mengshi; Ding, Liyun

    2015-12-01

    The magnetic fluorescent core-shell structured nanoparticles, Fe{sub 3}O{sub 4}@SiO{sub 2}(F)@meso–SiO{sub 2} nanoparticles, were prepared. Cholesterol oxidase (COD) was immobilized on their surface to form Fe{sub 3}O{sub 4}@SiO{sub 2}(F)@meso–SiO{sub 2}@COD nanoparticles. Optimal immobilization was achieved with 2.5% (v/v) APTES, 2.0% (v/v) GA, 10 mg COD (in 15 mg carrier) and solution pH of 7.0. Fe{sub 3}O{sub 4}@SiO{sub 2}(F)@meso–SiO{sub 2}@COD nanoparticles showed maximal catalytic activity at pH 7.0 and 50 °C. The thermal, storage and operational stabilities of COD were improved greatly after its immobilization. After the incubation at 50 °C for 5 h, the nanoparticles and free COD retained 80% and 46% of its initial activity, respectively. After kept at 4 °C for 30 days, the nanoparticles and free COD maintained 86% and 65% of initial activity, respectively. The nanoparticles retained 71% of its initial activity after 7 consecutive operations. Since Fe{sub 3}O{sub 4}@SiO{sub 2}(F)@meso–SiO{sub 2}@COD nanoparticles contained tris(2,2-bipyridyl)dichloro-ruthenium(II) hexahydrate (Ru(bpy){sub 3}Cl{sub 2}) and were optical sensitive to oxygen in solution, it might be used as the sensing material and has the application potential in multi parameter fiber optic biosensor based on enzyme catalysis and oxygen consumption. - Highlights: • COD was immobilized on magnetic fluorescent core-shell structured nanoparticles. • The nanoparticles were optical sensitive to oxygen in water solution. • The nanoparticles have remarkable improved stability compared with free COD. • The nanoparticles can probably be used in multi parameter fiber optic Biosensor.

  6. Some enzymatic properties of cholesterol oxidase produced by Brevibacterium sp Algumas propriedades enzimáticas da colesterol oxidase produzida por Brevibacterium sp.

    Directory of Open Access Journals (Sweden)

    Terezinha J.G. Salva

    1999-12-01

    Full Text Available In this study we determined some properties of the cholesterol oxidase from a Brevibacterium strain isolated from buffalo's milk and identified the cholesterol degradation products by the bacterial cell. A small fraction of the enzyme synthesized by cells cultured in liquid medium for 7days was released into the medium whereas a larger fraction remained bound to the cell membrane. The extraction of this fraction was efficiently accomplished in 1 mM phosphate buffer, pH 7.0, containing 0.7% Triton X-100. The enzyme stability under freezing and at 45oC was improved by addition of 20% glycerol. The optimum temperature and pH for the enzyme activity were 53°C and 7.5, respectively. The only steroidal product from cholesterol oxidation by the microbial cell and by the crude extract of the membrane-bound enzyme was 4-colesten-3-one. Chromatographic analysis showed that minor no steroidal compounds as well as 4-colesten-3-one found in the reaction media arose during fermentation process and were extracted together with the enzyme in the buffer solution. Cholesterol oxidation by the membrane-bound enzyme was a first order reaction type.Neste trabalho foram definidas algumas propriedades da enzima colesterol oxidase produzida por uma linhagem de Brevibacterium sp. isolada de leite de búfala e foram identificados os compostos resultantes da degradação do colesterol pela bactéria. Uma pequena fração da enzima sintetizada pelas células cultivadas em meio líquido por 7 dias foi liberada no meio de cultura e uma fração maior permaneceu ligada à membrana celular. A extração desta fração foi eficientemente efetuada em tampão fosfato 1mM, pH 7,0, contendo 0,7% de triton X-100. A estabilidade da enzima congelada e a 45oC foi aumentada pela adição de 20% de glicerol. A temperatura ótima para a atividade enzimática esteve ao redor de 53(0C e o pH ótimo esteve ao redor de 7,5. O único produto da degradação do colesterol, causada pela a

  7. Rhodococcus erythropolis ATCC 25544 as a suitable source of cholesterol oxidase: cell-linked and extracellular enzyme synthesis, purification and concentration

    Directory of Open Access Journals (Sweden)

    García-Carmona Francisco F

    2002-03-01

    Full Text Available Abstract Background The suitability of the strain Rhodococcus erythropolis ATCC 25544 grown in a two-liter fermentor as a source of cholesterol oxidase has been investigated. The strain produces both cell-linked and extracellular cholesterol oxidase in a high amount, that can be extracted, purified and concentrated by using the detergent Triton X-114. Results A spray-dry method of preparation of the enzyme inducer cholesterol in Tween 20 was found to be superior in both convenience and enzyme synthesis yield to one of heat-mixing. Both were similar as far as biomass yield is concerned. Cell-linked cholesterol oxidase was extracted with Triton X-114, and this detergent was also used for purification and concentration, following temperature-induced detergent phase separation. Triton X-114 was utilized to purify and to concentrate the cell-linked and the extracellular enzyme. Cholesterol oxidase was found mainly in the resulting detergent-rich phase. When Triton X-114 concentration was set to 6% w/v the extracellular, but not the cell-extracted enzyme, underwent a 3.4-fold activation after the phase separation process. This result is interpreted in the light of interconvertible forms of the enzyme that do not seem to be in equilibrium. Fermentation yielded 360 U/ml (672 U/ml after activation, 36% of which was extracellular (65% after activation. The Triton X-114 phase separation step yielded 11.6-fold purification and 20.3-fold concentration. Conclusions The results of this work may make attractive and cost-effective the implementation of this bacterial strain and this detergent in a purification-based industrial production scheme of commercial cholesterol oxidase.

  8. Rhodococcus erythropolis ATCC 25544 as a suitable source of cholesterol oxidase: cell-linked and extracellular enzyme synthesis, purification and concentration.

    Science.gov (United States)

    Sojo, Mar M; Bru, Roque R; García-Carmona, Francisco F

    2002-03-26

    The suitability of the strain Rhodococcus erythropolis ATCC 25544 grown in a two-liter fermentor as a source of cholesterol oxidase has been investigated. The strain produces both cell-linked and extracellular cholesterol oxidase in a high amount, that can be extracted, purified and concentrated by using the detergent Triton X-114. A spray-dry method of preparation of the enzyme inducer cholesterol in Tween 20 was found to be superior in both convenience and enzyme synthesis yield to one of heat-mixing. Both were similar as far as biomass yield is concerned. Cell-linked cholesterol oxidase was extracted with Triton X-114, and this detergent was also used for purification and concentration, following temperature-induced detergent phase separation. Triton X-114 was utilized to purify and to concentrate the cell-linked and the extracellular enzyme. Cholesterol oxidase was found mainly in the resulting detergent-rich phase. When Triton X-114 concentration was set to 6% w/v the extracellular, but not the cell-extracted enzyme, underwent a 3.4-fold activation after the phase separation process. This result is interpreted in the light of interconvertible forms of the enzyme that do not seem to be in equilibrium. Fermentation yielded 360 U/ml (672 U/ml after activation), 36% of which was extracellular (65% after activation). The Triton X-114 phase separation step yielded 11.6-fold purification and 20.3-fold concentration. The results of this work may make attractive and cost-effective the implementation of this bacterial strain and this detergent in a purification-based industrial production scheme of commercial cholesterol oxidase.

  9. Covalent attachment of cholesterol oxidase and horseradish peroxidase on perlite through silanization: activity, stability and co-immobilization.

    Science.gov (United States)

    Torabi, Seyed-Fakhreddin; Khajeh, Khosro; Ghasempur, Salehe; Ghaemi, Nasser; Siadat, Seyed-Omid Ranaei

    2007-08-31

    In the present work, co-immobilization of cholesterol oxidase (COD) and horseradish peroxidase (POD) on perlite surface was attempted. The surface of perlite were activated by 3-aminopropyltriethoxysilane and covalently bonded with COD and POD via glutaraldehyde. Enzymes activities have been assayed by spectrophotometric technique. The stabilities of immobilized COD and POD to pH were higher than those of soluble enzymes and immobilization shifted optimum pH of enzymes to the lower pH. Heat inactivation studies showed improved thermostability of the immobilized COD for more than two times, but immobilized POD was less thermostable than soluble POD. Also activity recovery of immobilized COD was about 50% since for immobilized POD was 11%. The K(m) of immobilized enzymes was found slightly lower than that of soluble enzymes. Immobilized COD showed inhibition in its activity at high cholesterol concentration which was not reported for soluble COD before. Co-immobilized enzymes retained 65% of its initial activity after 20 consecutive reactor batch cycles.

  10. Strong Negative Interference by Calcium Dobesilate in Sarcosine Oxidase Assays for Serum Creatinine Involving the Trinder Reaction.

    Science.gov (United States)

    Guo, Xiuzhi; Hou, Li'an; Cheng, Xinqi; Zhang, Tianjiao; Yu, Songlin; Fang, Huiling; Xia, Liangyu; Qi, Zhihong; Qin, Xuzhen; Zhang, Lin; Liu, Qian; Liu, Li; Chi, Shuling; Hao, Yingying; Qiu, Ling

    2015-06-01

    The vasoprotective drug calcium dobesilate is known to interfere with creatinine (Cr) quantifications in sarcosine oxidase enzymatic (SOE) assays. The aim of this study was to investigate this interference in 8 different commercially available assays and to determine its clinical significance. In in vitro experiments, interference was evaluated at 3 Cr levels. For this, Cr was quantified by SOE assays in pooled serum supplemented with calcium dobesilate at final concentrations of 0, 2, 4, 8, 16, 32, and 64 μg/mL. Percent bias was calculated relative to the drug-free specimen. For in vivo analyses, changes in serum concentrations of Cr, cystatin C (CysC; a renal function marker), and calcium dobesilate were monitored in healthy participants of group I before and after oral calcium dobesilate administration. In addition, variations in interference were also examined among different SOE assays using serum obtained from healthy participants of group II. Lastly, Cr levels from the 10 patients treated with calcium dobesilate were measured using 4 SOE assays and liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) for comparison. Our in vitro analyses indicated that the presence of 8 μg/mL calcium dobesilate resulted in a -4.4% to -36.3% reduction in Cr serum concentration compared to drug-free serum for 8 SOE assays examined. In vivo, Cr values decreased relative to the baseline level with increasing drug concentration, with the lowest Cr levels obtained at 2 or 3 hours after drug administration in participants of group I. The observed Cr concentrations for participants in group II were reduced by -28.5% to -3.1% and -60.5% to -11.6% at 0 and 2 hours after administration related to baseline levels. The Cr values of 10 patients measured by Roche, Beckman, Maker, and Merit Choice SOE assays showed an average deviation of -20.0%, -22.4%, -14.2%, and -29.6%, respectively, compared to values obtained by LC-IDMS/MS. These results revealed a

  11. Strong Negative Interference by Calcium Dobesilate in Sarcosine Oxidase Assays for Serum Creatinine Involving the Trinder Reaction

    Science.gov (United States)

    Guo, Xiuzhi; Hou, Li’an; Cheng, Xinqi; Zhang, Tianjiao; Yu, Songlin; Fang, Huiling; Xia, Liangyu; Qi, Zhihong; Qin, Xuzhen; Zhang, Lin; Liu, Qian; Liu, Li; Chi, Shuling; Hao, Yingying; Qiu, Ling

    2015-01-01

    Abstract The vasoprotective drug calcium dobesilate is known to interfere with creatinine (Cr) quantifications in sarcosine oxidase enzymatic (SOE) assays. The aim of this study was to investigate this interference in 8 different commercially available assays and to determine its clinical significance. In in vitro experiments, interference was evaluated at 3 Cr levels. For this, Cr was quantified by SOE assays in pooled serum supplemented with calcium dobesilate at final concentrations of 0, 2, 4, 8, 16, 32, and 64 μg/mL. Percent bias was calculated relative to the drug-free specimen. For in vivo analyses, changes in serum concentrations of Cr, cystatin C (CysC; a renal function marker), and calcium dobesilate were monitored in healthy participants of group I before and after oral calcium dobesilate administration. In addition, variations in interference were also examined among different SOE assays using serum obtained from healthy participants of group II. Lastly, Cr levels from the 10 patients treated with calcium dobesilate were measured using 4 SOE assays and liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) for comparison. Our in vitro analyses indicated that the presence of 8 μg/mL calcium dobesilate resulted in a −4.4% to −36.3% reduction in Cr serum concentration compared to drug-free serum for 8 SOE assays examined. In vivo, Cr values decreased relative to the baseline level with increasing drug concentration, with the lowest Cr levels obtained at 2 or 3 hours after drug administration in participants of group I. The observed Cr concentrations for participants in group II were reduced by −28.5% to −3.1% and −60.5% to −11.6% at 0 and 2 hours after administration related to baseline levels. The Cr values of 10 patients measured by Roche, Beckman, Maker, and Merit Choice SOE assays showed an average deviation of −20.0%, −22.4%, −14.2%, and −29.6%, respectively, compared to values obtained by LC

  12. Cholesterol

    Science.gov (United States)

    ... found in some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods. Another type, trans fat, is in some fried and processed foods. Eating these fats can raise your LDL (bad) cholesterol. Lack of physical activity, with lots of ...

  13. AOPPs (advanced oxidation protein products) promote apoptosis in trophoblastic cells through interference with NADPH oxidase signaling: implications for preeclampsia.

    Science.gov (United States)

    Wang, Shuo-shi; Huang, Qi-tao; Zhong, Mei; Yin, Qian

    2015-01-01

    To investigate the role of placental advanced oxidation protein products (AOPPs) in the pathogenesis of preeclampsia (PE). Expression of AOPPs in human placental tissues collected from women with or without PE was examined by immunohistochemistry. The effect of AOPPs on in vitro trophoblast cell function was also examined. Specifically, we exposed trophoblastic cells to AOPPs and measured the production of human chorionic gonadotropin (hCG) as well as their invasion capacity using an in vitro Transwell invasion assay. We also investigated the effect of AOPPs on trophoblastic apoptosis and whether this effect could be mediated through interference in NADPH oxidase signaling. AOPPs were expressed in placental tissues, and were significantly increased in placentas from women with PE versus normotensive controls. AOPPs also affected trophoblast cell function in vitro by significantly reducing β-HCG production and inhibiting trophoblas cell invasive capacity. Exposure to AOPPs significantly increased apoptosis in trophoblastic cells, which was mediated through the NADPH oxidase pathway. AOPPs expression is increased in PE placentas and exposure to AOPPs adversely affects trophoblast cell function, which may contribute to the shallow trophoblast invasion that characterizes this disorder. Additional studies are needed to investigate further to determine whether AOPPs can be used as a biomarker for PE.

  14. An Oxidase-Based Electrochemical Fluidic Sensor with High-Sensitivity and Low-Interference by On-Chip Oxygen Manipulation

    Directory of Open Access Journals (Sweden)

    Chang-Soo Kim

    2012-06-01

    Full Text Available Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide. Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc. to implement a viable component for in-line fluidic sensor systems.

  15. Minimizing the effects of oxygen interference on l-lactate sensors by a single amino acid mutation in Aerococcus viridansl-lactate oxidase.

    Science.gov (United States)

    Hiraka, Kentaro; Kojima, Katsuhiro; Lin, Chi-En; Tsugawa, Wakako; Asano, Ryutaro; La Belle, Jeffrey T; Sode, Koji

    2018-04-30

    l-lactate biosensors employing l-lactate oxidase (LOx) have been developed mainly to measure l-lactate concentration for clinical diagnostics, sports medicine, and the food industry. Some l-lactate biosensors employ artificial electron mediators, but these can negatively impact the detection of l-lactate by competing with the primary electron acceptor: molecular oxygen. In this paper, a strategic approach to engineering an AvLOx that minimizes the effects of oxygen interference on sensor strips was reported. First, we predicted an oxygen access pathway in Aerococcus viridans LOx (AvLOx) based on its crystal structure. This was subsequently blocked by a bulky amino acid substitution. The resulting Ala96Leu mutant showed a drastic reduction in oxidase activity using molecular oxygen as the electron acceptor and a small increase in dehydrogenase activity employing an artificial electron acceptor. Secondly, the Ala96Leu mutant was immobilized on a screen-printed carbon electrode using glutaraldehyde cross-linking method. Amperometric analysis was performed with potassium ferricyanide as an electron mediator under argon or atmospheric conditions. Under argon condition, the response current increased linearly from 0.05 to 0.5mM l-lactate for both wild-type and Ala96Leu. However, under atmospheric conditions, the response of wild-type AvLOx electrode was suppressed by 9-12% due to oxygen interference. The Ala96Leu mutant maintained 56-69% of the response current at the same l-lactate level and minimized the relative bias error to -19% from -49% of wild-type. This study provided significant insight into the enzymatic reaction mechanism of AvLOx and presented a novel approach to minimize oxygen interference in sensor applications, which will enable accurate detection of l-lactate concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Ethamsylate (Dicynone) interference in determination of serum creatinine, uric acid, triglycerides, and cholesterol in assays involving the Trinder reaction; in vivo and in vitro.

    Science.gov (United States)

    Dastych, Milan; Wiewiorka, Ondrej; Benovská, Miroslava

    2014-01-01

    The aim of our research was the quantification of interfering properties of the haemostatic drug Dicynone (ethamsylate) in serum creatinine, uric acid, cholesterol, and triglyceride assays using the Trinder reaction. Blood from patients was collected before and 15 minutes after administration of 500 mg Dicynone dose i.v. and the above mentioned analytes were quantified using Roche assays (Cobas 8000). In our in vitro experiment, we measured concentrations of the analytes in pooled serum aliquots with final concentrations of Dicynone additions 0, 30, 60, 150, and 300 mg/L. Aliquots with 60 mg/L Dicynone were also measured at 2, 6, and 8 hours after initial measurement when stored in 22 degrees C and 4 degrees C for comparison. Concentrations of the measured analytes in samples from patients administered with a 500 mg dose of Dicynone were lower in all cases (n = 10) when compared to values in samples taken immediately before treatment. The in vitro samples showed that considerable negative interference occurred even with the low concentrations of Dicynone additions (30 and 60 mg/L), showing the strongest negative interference in creatinine values, followed by uric acid, triglycerides, and cholesterol. Using in vitro samples, we showed strong time and temperature dependence on Dicynone interference. We found and proved significant negative interference of the drug Dicynone (ethamsylate) in the clinical analysis of blood using in vivo and in vitro experiments. Furthermore, we observed a change of this effect in serum matrix over time and at different storage temperatures.

  17. Production, Purification, and Identification of Cholest-4-en-3-one Produced by Cholesterol Oxidase from sp. in Aqueous/Organic Biphasic System

    Directory of Open Access Journals (Sweden)

    Ke Wu

    2015-01-01

    Full Text Available Cholest-4-en-3-one has positive uses against obesity, liver disease, and keratinization. It can be applied in the synthesis of steroid drugs as well. Most related studies are focused on preparation of cholest-4-en-3-one by using whole cells as catalysts, but production of high-quality cholest-4-en-3-one directly from cholesterol oxidase (COD using an aqueous/organic two-phase system has been rarely explored. This study set up an enzymatic reaction system to produce cholest-4-en-3-one. We developed and optimized the enzymatic reaction system using COD from COX5-6 (a strain of Rhodococcus instead of whole-cell biocatalyst. This not only simplifies and accelerates the production but also benefits the subsequent separation and purification process. Through extraction, washing, evaporation, column chromatography, and recrystallization, we got cholest-4-en-3-one with purity of 99.78%, which was identified by nuclear magnetic resonance, mass spectroscopy, and infrared spectroscopy. In addition, this optimized process of cholest-4-en-3-one production and purification can be easily scaled up for industrial production, which can largely decrease the cost and guarantee the purity of the product.

  18. RNA interference of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO1 and ACO2) genes expression prolongs the shelf life of Eksotika (Carica papaya L.) papaya fruit.

    Science.gov (United States)

    Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom; Yeong, Wee Chien; Pillai, Vilasini

    2014-06-19

    The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6). Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.

  19. RNA Interference of 1-Aminocyclopropane-1-carboxylic Acid Oxidase (ACO1 and ACO2 Genes Expression Prolongs the Shelf Life of Eksotika (Carica papaya L. Papaya Fruit

    Directory of Open Access Journals (Sweden)

    Rogayah Sekeli

    2014-06-01

    Full Text Available The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6. Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.

  20. Biogenesis of plasma membrane cholesterol

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Y.

    1986-05-01

    A striking feature of the molecular organization of eukaryotic cells is the singular enrichment of their plasma membranes in sterols. The authors studies are directed at elucidating the mechanisms underlying this inhomogeneous disposition. Cholesterol oxidase catalyzes the oxidation of plasma membrane cholesterol in intact cells, leaving intracellular cholesterol pools untouched. With this technique, the plasma membrane was shown to contain 95% of the unesterified cholesterol of cultured human fibroblasts. Cholesterol synthesized from (/sup 3/H) acetate moved to the plasma membrane with a half-time of 1 h at 37/sup 0/C. They used equilibrium gradient centrifugation of homogenates of biosynthetically labeled, cholesterol oxidase treated cells to examine the distribution of newly synthesized sterols among intracellular pools. Surprisingly, lanosterol, a major precursor of cholesterol, and intracellular cholesterol both peaked at much lower buoyant density than did 3-hydroxy-3-methylglutaryl-CoA reductase. This suggests that cholesterol biosynthesis is not taken to completion in the endoplasmic reticulum. The cholesterol in the buoyant fraction eventually moved to the plasma membrane. Digitonin treatment increased the density of the newly synthesized cholesterol fractions, indicating that nascent cholesterol in transit is associated with cholesterol-rich membranes. The authors are testing the hypothesis that the pathway of cholesterol biosynthesis is spatially organized in various intracellular membranes such that the sequence of biosynthetic steps both concentrates the sterol and conveys it to the plasma membrane.

  1. Dietary Phenolic Compounds Interfere with the Fate of Hydrogen Peroxide in Human Adipose Tissue but Do Not Directly Inhibit Primary Amine Oxidase Activity

    Directory of Open Access Journals (Sweden)

    Christian Carpéné

    2016-01-01

    Full Text Available Resveratrol has been reported to inhibit monoamine oxidases (MAO. Many substrates or inhibitors of neuronal MAO interact also with other amine oxidases (AO in peripheral organs, such as semicarbazide-sensitive AO (SSAO, known as primary amine oxidase, absent in neurones, but abundant in adipocytes. We asked whether phenolic compounds (resveratrol, pterostilbene, quercetin, and caffeic acid behave as MAO and SSAO inhibitors. AO activity was determined in human adipose tissue. Computational docking and glucose uptake assays were performed in 3D models of human AO proteins and in adipocytes, respectively. Phenolic compounds fully inhibited the fluorescent detection of H2O2 generated during MAO and SSAO activation by tyramine and benzylamine. They also quenched H2O2-induced fluorescence in absence of biological material and were unable to abolish the oxidation of radiolabelled tyramine and benzylamine. Thus, phenolic compounds hampered H2O2 detection but did not block AO activity. Only resveratrol and quercetin partially impaired MAO-dependent [14C]-tyramine oxidation and behaved as MAO inhibitors. Phenolic compounds counteracted the H2O2-dependent benzylamine-stimulated glucose transport. This indicates that various phenolic compounds block downstream effects of H2O2 produced by biogenic or exogenous amine oxidation without directly inhibiting AO. Phenolic compounds remain of interest regarding their capacity to limit oxidative stress rather than inhibiting AO.

  2. Dietary Phenolic Compounds Interfere with the Fate of Hydrogen Peroxide in Human Adipose Tissue but Do Not Directly Inhibit Primary Amine Oxidase Activity.

    Science.gov (United States)

    Carpéné, Christian; Hasnaoui, Mounia; Balogh, Balázs; Matyus, Peter; Fernández-Quintela, Alfredo; Rodríguez, Víctor; Mercader, Josep; Portillo, Maria P

    2016-01-01

    Resveratrol has been reported to inhibit monoamine oxidases (MAO). Many substrates or inhibitors of neuronal MAO interact also with other amine oxidases (AO) in peripheral organs, such as semicarbazide-sensitive AO (SSAO), known as primary amine oxidase, absent in neurones, but abundant in adipocytes. We asked whether phenolic compounds (resveratrol, pterostilbene, quercetin, and caffeic acid) behave as MAO and SSAO inhibitors. AO activity was determined in human adipose tissue. Computational docking and glucose uptake assays were performed in 3D models of human AO proteins and in adipocytes, respectively. Phenolic compounds fully inhibited the fluorescent detection of H2O2 generated during MAO and SSAO activation by tyramine and benzylamine. They also quenched H2O2-induced fluorescence in absence of biological material and were unable to abolish the oxidation of radiolabelled tyramine and benzylamine. Thus, phenolic compounds hampered H2O2 detection but did not block AO activity. Only resveratrol and quercetin partially impaired MAO-dependent [(14)C]-tyramine oxidation and behaved as MAO inhibitors. Phenolic compounds counteracted the H2O2-dependent benzylamine-stimulated glucose transport. This indicates that various phenolic compounds block downstream effects of H2O2 produced by biogenic or exogenous amine oxidation without directly inhibiting AO. Phenolic compounds remain of interest regarding their capacity to limit oxidative stress rather than inhibiting AO.

  3. Cholesterol Regulates Multiple Forms of Vesicle Endocytosis at a Mammalian Central Synapse

    Science.gov (United States)

    Yue, Hai-Yuan; Xu, Jianhua

    2015-01-01

    Endocytosis in synapses sustains neurotransmission by recycling vesicle membrane and maintaining the homeostasis of synaptic membrane. A role of membrane cholesterol in synaptic endocytosis remains controversial because of conflicting observations, technical limitations in previous studies, and potential interference from nonspecific effects after cholesterol manipulation. Furthermore, it is unclear whether cholesterol participates in distinct forms of endocytosis that function under different activity levels. In this study, applying the whole-cell membrane capacitance measurement to monitor endocytosis in real time at the rat calyx of Held terminals, we found that disrupting cholesterol with dialysis of cholesterol oxidase (COase) or methyl-β-cyclodextrin (MCD) impaired three different forms of endocytosis, i.e., slow endocytosis, rapid endocytosis, and endocytosis of the retrievable membrane that exists at the surface before stimulation. The effects were observed when disruption of cholesterol was mild enough not to change Ca2+ channel current or vesicle exocytosis, indicative of stringent cholesterol requirement in synaptic endocytosis. Extracting cholesterol with high concentrations of MCD reduced exocytosis, mainly by decreasing the readily releasable pool (RRP) and the vesicle replenishment after RRP depletion. Our study suggests that cholesterol is an important, universal regulator in multiple forms of vesicle endocytosis at mammalian central synapses. PMID:25893258

  4. Cholesterol regulates multiple forms of vesicle endocytosis at a mammalian central synapse.

    Science.gov (United States)

    Yue, Hai-Yuan; Xu, Jianhua

    2015-07-01

    Endocytosis in synapses sustains neurotransmission by recycling vesicle membrane and maintaining the homeostasis of synaptic membrane. A role of membrane cholesterol in synaptic endocytosis remains controversial because of conflicting observations, technical limitations in previous studies, and potential interference from non-specific effects after cholesterol manipulation. Furthermore, it remains unclear whether cholesterol participates in distinct forms of endocytosis that function under different activity levels. In this study, applying the whole-cell membrane capacitance measurement to monitor endocytosis in real time at the rat calyx of Held terminals, we found that disrupting cholesterol with dialysis of cholesterol oxidase or methyl-β-cyclodextrin impaired three different forms of endocytosis, including slow endocytosis, rapid endocytosis, and endocytosis of the retrievable membrane that exists at the surface before stimulation. The effects were observed when disruption of cholesterol was mild enough not to change Ca(2+) channel current or vesicle exocytosis, indicative of stringent cholesterol requirement in synaptic endocytosis. Extracting cholesterol with high concentrations of methyl-β-cyclodextrin reduced exocytosis, mainly by decreasing the readily releasable pool and the vesicle replenishment after readily releasable pool depletion. Our study suggests that cholesterol is an important, universal regulator in multiple forms of vesicle endocytosis at mammalian central synapses. © 2015 International Society for Neurochemistry.

  5. Oral Administration of L-Arginine in Patients With Angina or Following Myocardial Infarction May Be Protective By Increasing Plasma Superoxide Dismutase and Total Thiols With Reduction in Serum Cholesterol and Xanthine Oxidase

    Directory of Open Access Journals (Sweden)

    Pratima Tripathi

    2009-01-01

    Full Text Available Administration of L-arginine has been shown to control ischemic injury by producing nitric oxide which dilates the vessels and thus maintains proper blood flow to the myocardium. In the present study attempt has been made to determine whether oral administration of L-arginine has any effect on oxidant/antioxidant homeostasis in ischemic myocardial patients [represented by the patients of acute angina (AA and acute myocardial infarction (MI]. L-arginine has antioxidant and antiapoptotic properties, decreases endothelin-1 expression and improves endothelial function, thereby controlling oxidative injury caused during myocardial ischemic syndrome. Effect of L-arginine administration on the status of free radical scavenging enzymes, pro-oxidant enzyme and antioxidants viz. total thiols, carbonyl content and plasma ascorbic acid levels in the patients has been evaluated. We have observed that L-arginine administration (three grams per day for 15 days resulted in increased activity of free radical scavenging enzyme superoxide dismutase (SOD and increase in the levels of total thiols (T-SH and ascorbic acid with concomitant decrease in lipid per-oxidation, carbonyl content, serum cholesterol and the activity of proxidant enzyme, xanthine oxidase (XO. These findings suggest that the supplementation of L-arginine along with regular therapy may be beneficial to the patients of ischemic myocardial syndromes.

  6. About Cholesterol

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More About Cholesterol Updated:Jul 5,2017 Whether you’ve just ... Quiz This content was last reviewed April 2017. Cholesterol • Home • About Cholesterol Introduction Atherosclerosis What Your Cholesterol ...

  7. Intracellular transport of cholesterol in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Brasaemle, D.L.

    1989-01-01

    The erythrocyte was selected as a simple cell for the study of transbilayer movement of cholesterol. Cholesterol oxidase was used to measure the distribution of ({sup 3}H)cholesterol across the erythrocyte membrane. Cholesterol oxidase was also used to estimate the rate of transport of low density lipoprotein (LDL) cholesterol to the plasma membrane of cultured Chinese hamster ovary (CHO) fibroblasts; the half-time of this process was 42 minutes. The rate of transport of LDL cholesterol to the plasma membrane was confirmed by a second procedure using amphotericin B. Amphotericin B was also used to estimate the rate of transport of endogenously synthesized cholesterol to the plasma membrane of CHO cells. New methodology was developed including improvements of the previously published cholesterol oxidase assay for plasma membrane cholesterol. A new method for detecting transport of cholesterol to the plasma membrane in cultured cells was developed using amphotericin B. Preliminary studies investigated the use of fluorescent polyenes, pimaricin and etruscomycin, as probes for plasma membrane cholesterol in transport studies. Finally, a modification of a previously published cell staining protocol yielded a simple, quantitative assay for cell growth.

  8. Cholesterol Levels

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/cholesterollevels.html Cholesterol Levels To use the sharing features on this page, please enable JavaScript. What is a Cholesterol Test? Cholesterol is a waxy, fat-like substance ...

  9. Cholesterol (image)

    Science.gov (United States)

    Cholesterol is a soft, waxy substance that is present in all parts of the body including the ... and obtained from animal products in the diet. Cholesterol is manufactured in the liver and is needed ...

  10. Cholesterol and lifestyle

    Science.gov (United States)

    Hyperlipidemia - cholesterol and lifestyle; CAD - cholesterol and lifestyle; Coronary artery disease - cholesterol and lifestyle; Heart disease - cholesterol and lifestyle; Prevention - cholesterol and lifestyle; ...

  11. Tumor suppressive effect of lysyl oxidase proenzyme.

    Science.gov (United States)

    Contente, Sara; Yeh, Tze-Jou Annie; Friedman, Robert M

    2009-07-01

    Lysyl oxidase acts as both a matrix modifying enzyme and an oncogene suppressor. It is synthesized as a 50-kDa proenzyme, secreted, and processed into an approximately 30 kDa mature, active enzyme and an 18-kDa propeptide. The tumor suppressive effect of lysyl oxidase appears to be exerted within the cell, so the subcellular localization of protein forms was investigated. Propeptide-specific antibody detected 50-kDa proenzyme in cytoplasmic and nuclear extracts of non-transformed mouse fibroblasts, but free 18-kDa propeptide was not detected in any extract. Antibody to epitope near the N-terminus of mature lysyl oxidase detected the proenzyme product in non-transformed cells, and a 30-kDa cytoplasmic protein in both non-transformed and transformed cells. RNA interference reduced the expression of lysyl oxidase mRNA and 50-kDa proenzyme in non-transformed cells, but had no effect on 30-kDa protein, indicating that although this protein displays a lysyl oxidase epitope, it is not derived from lysyl oxidase message. The absence of both free 18-kDa propeptide and mature lysyl oxidase within non-transformed cells suggests that cellular reversion after restoration of lysyl oxidase gene expression is mediated by the 50-kDa proenzyme within cells.

  12. What's Cholesterol?

    Science.gov (United States)

    ... the foods you eat. Meat, fish, eggs, butter, cheese, and whole or low-fat milk all have cholesterol in them. You Need a Little, Not a ... are some foods that have a lot of cholesterol? Meat, eggs, butter, cheese, and milk (and stuff that's made with some ...

  13. High blood cholesterol levels

    Science.gov (United States)

    Cholesterol - high; Lipid disorders; Hyperlipoproteinemia; Hyperlipidemia; Dyslipidemia; Hypercholesterolemia ... There are many types of cholesterol. The ones talked about most are: ... lipoprotein (HDL) cholesterol -- often called "good" cholesterol ...

  14. Spirogyra neglecta inhibits the absorption and synthesis of cholesterol in vitro

    Directory of Open Access Journals (Sweden)

    Acharaporn Duangjai

    2016-12-01

    Conclusion: These observations suggested that inhibitory cholesterol absorption effects of SN could be mediated through the modulation of size and solubility of cholesterol micelles, resulting in interference of cholesterol uptake. In addition, SN inhibited the rate limiting step of cholesterol synthesis. This study provides supporting evidence for the potential usage of SN as a cholesterol lowering agent.

  15. Cholesterol IQ Quiz

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Cholesterol IQ Quiz Updated:Jul 5,2017 Begin the quiz Cholesterol • Home • About Cholesterol Introduction Atherosclerosis What Your Cholesterol ...

  16. High Blood Cholesterol

    Science.gov (United States)

    ... To Health Topics / High Blood Cholesterol High Blood Cholesterol Also known as Hypercholesterolemia High blood cholesterol is ... Lipid panel tests to check for healthy blood cholesterol levels Doctors use lipid panels to check whether ...

  17. Cholesterol and Your Child

    Science.gov (United States)

    ... Needs a Kidney Transplant Vision Facts and Myths Cholesterol KidsHealth > For Parents > Cholesterol Print A A A ... español El colesterol y su hijo What Is Cholesterol? Cholesterol is a waxy substance made by the ...

  18. Terminal oxidases of cyanobacteria.

    Science.gov (United States)

    Hart, S E; Schlarb-Ridley, B G; Bendall, D S; Howe, C J

    2005-08-01

    The respiratory chain of cyanobacteria appears to be branched rather than linear; furthermore, respiratory and photosynthetic electron-transfer chains co-exist in the thylakoid membrane and even share components. This review will focus on the three types of terminal respiratory oxidases identified so far on a genetic level in cyanobacteria: aa3-type cytochrome c oxidase, cytochrome bd-quinol oxidase and the alternative respiratory terminal oxidase. We summarize here their genetic, biochemical and biophysical characterization to date and discuss their interactions with electron donors as well as their physiological roles.

  19. What Is Cholesterol?

    Science.gov (United States)

    ... School Counselors Kidney Stones Brain and Nervous System Cholesterol KidsHealth > For Teens > Cholesterol Print A A A ... High Cholesterol? en español ¿Qué es el colesterol? Cholesterol Is a Fat in the Blood Cholesterol (kuh- ...

  20. The human lysyl oxidase-like 2 protein functions as an amine oxidase toward collagen and elastin.

    Science.gov (United States)

    Kim, Young-Mi; Kim, Eun-Cheol; Kim, Youngho

    2011-01-01

    The lysyl oxidase-like 2 (LOXL2) protein is a human paralogue of lysyl oxidase (LOX) that functions as an amine oxidase for formation of lysine-derived cross-links found in collagen and elastin. In addition to the C-terminal domains characteristic to the LOX family members, LOXL2 contains four scavenger receptor cysteine-rich (SRCR) domains in the N-terminus. In order to assess the amine oxidase activity of LOXL2, we expressed a series of recombinant LOXL2 proteins with deletions in the SRCR domains, using an Escherichia coli expression system. All of the purified recombinant LOXL2 proteins, with or without the SRCR domains in the N-terminus, showed significant amine oxidase activity toward several different types of collagen and elastin in in vitro amine oxidase assays, indicating deletion of the SRCR domains does not interfere with amine oxidase activity of LOXL2. Further, amine oxidase activity of LOXL2 was not susceptible to inhibition by β-aminopropionitrile, an irreversible inhibitor of LOX, suggesting a different enzymatic mechanism between these two paralogues.

  1. Causes of High Cholesterol

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Causes of High Cholesterol Updated:Nov 16,2017 If you have high ... for a heart or stroke event? Find out . Cholesterol • Home • About Cholesterol • HDL, LDL, and Triglycerides • Causes ...

  2. Cholesterol Facts and Statistics

    Science.gov (United States)

    ... Blood Pressure Salt Million Hearts® WISEWOMAN Program High Cholesterol Facts Recommend on Facebook Tweet Share Compartir Find ... about high cholesterol in the United States. High Cholesterol in the United States In 2011–2012, 78 ...

  3. Cholesterol testing and results

    Science.gov (United States)

    Cholesterol test results; LDL test results; VLDL test results; HDL test results; Coronary risk profile results; Hyperlipidemia-results; Lipid disorder test results; Heart disease - cholesterol results

  4. Fabrication and Optimization of ChE/ChO/HRP-AuNPs/c-MWCNTs Based Silver Electrode for Determining Total Cholesterol in Serum

    Directory of Open Access Journals (Sweden)

    Kusum Lata

    2016-01-01

    Full Text Available The developed method used three enzymes comprised of cholesterol esterase, cholesterol oxidase, and peroxidase for fabrication of amperometric biosensor in order to determine total cholesterol in serum samples. Gold nanoparticles (AuNPs and carboxylated multiwall carbon nanotubes (cMWCNTs were used to design core of working electrode, having covalently immobilized ChO, ChE, and HRP. Polyacrylamide layer was finally coated on working electrode in order to prevent enzyme leaching. Chemically synthesised Au nanoparticles were subjected to transmission electron microscopy (TEM for analysing the shape and size of the particles. Working electrode was subjected to FTIR and XRD. The combined action of AuNP and c-MWCNT showed enhancement in electrocatalytic activity at a very low potential of 0.27 V. The pH 7, temperature 40°C, and response time of 20 seconds, respectively, were observed. The biosensor shows a broad linear range from 0.5 mg/dL to 250 mg/dL (0.01 mM–5.83 mM with minimum detection limit being 0.5 mg/dL (0.01 mM. The biosensor showed reusability of more than 45 times and was stable for 60 days. The biosensor was successfully tested for determining total cholesterol in serum samples amperometrically with no significant interference by serum components.

  5. The ultrasonic effect on the mechanism of cholesterol oxidase ...

    African Journals Online (AJOL)

    ultrasonic on cell membrane and to facilitate enzyme excretion, transmission electron microscopy (TEM) was employed. Scanning of the bacterial cells by TEM also first revealed that holes appeared in the cytoplasmic region, then excluded from the cell barrage, and finally self-destructed with higher irradiating dosage.

  6. The ultrasonic effect on the mechanism of cholesterol oxidase ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-04-26

    Apr 26, 2010 ... ses has also aroused great interest and attention with the popularity and development of ultrasonic equipment in recent years. This study shows that a .... Cavitation bubbles shrink under heat insulation conditions, and even instantly collapse. In the twinkling, the super high temperature of 5000°C and ...

  7. A DNA-Assembled Fe3O4@Ag Nanorod in Silica Matrix for Cholesterol Biosensing

    Science.gov (United States)

    Satvekar, R. K.; Tiwari, A. P.; Rohiwal, S. S.; Tiwale, B. M.; Pawar, S. H.

    2015-12-01

    A novel nanocomposite having DNA-assembled Fe3O4@Ag nanorods in silica matrix has been proposed for fabrication of bienzymatic cholesterol nanobiosensor. Cholesterol oxidase and horseradish peroxidase have been co-encapsulated in Silica/Fe3O4@Ag-DNA nanocomposite deposited on the indium tin oxide electrode. Cyclic voltammetry was employed for the electrochemical behavior of proposed biosensor and used to estimate cholesterol with a linear range of 5-195 mg/dL.

  8. STABILITY AND STOICHIOMETRY OF BILAYER PHOSPHOLIPID-CHOLESTEROL COMPLEXES: RELATIONSHIP TO CELLULAR STEROL DISTRIBUTION AND HOMEOSTASIS&

    Science.gov (United States)

    Lange, Yvonne; Ali Tabei, S. M.; Ye, Jin; Steck, Theodore L.

    2013-01-01

    Does cholesterol distribute among intracellular compartments by passive equilibration down its chemical gradient? If so, its distribution should reflect the relative cholesterol affinity of the constituent membrane phospholipids as well as their ability to form stoichiometric cholesterol complexes. We tested this hypothesis by analyzing the reactivity to cholesterol oxidase of large unilamellar vesicles (LUVs) containing biological phospholipids plus varied cholesterol. The rates of cholesterol oxidation differed among the various phospholipid environments by roughly four orders of magnitude. Furthermore, accessibility to the enzyme increased by orders of magnitude at cholesterol thresholds that suggested stoichiometries of association of 1:1, 2:3 or 1:2 cholesterol:phospholipid (mol:mol). Cholesterol accessibility above the threshold was still constrained by its particular phospholipid environment. One phospholipid, 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidylserine, exhibited no threshold. The analysis suggested values for the relative stabilities of the cholesterol-phospholipid complexes and for the fractions of bilayer cholesterol not in complexes at the threshold equivalence points; predictably, the saturated phosphorylcholine species had the lowest stoichiometries and the strongest affinities for cholesterol. These results were in general agreement with the equilibrium distribution of cholesterol between the various LUVs and methyl-β-cyclodextrin. In addition, the properties of the cholesterol in intact human red blood cells matched predictions made from LUVs of the corresponding composition. These results support a passive mechanism for the intracellular distribution of cholesterol that can provide a signal for its homeostatic regulation. PMID:24000774

  9. Get Your Cholesterol Checked

    Science.gov (United States)

    ... cholesterol levels with a blood test called a lipid profile. For the test, a nurse will take a ... blood tests that can check cholesterol, but a lipid profile gives the most information. Find out more about ...

  10. Controlling Cholesterol with Statins

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Controlling Cholesterol with Statins Share Tweet Linkedin Pin it More ... not, the following tips can help keep your cholesterol in check: Talk with your healthcare provider about ...

  11. Low Cholesterol Diet

    Science.gov (United States)

    ... changes (TLC) and medicines. TLC includes a healthy diet, weight management, and regular physical activity. What is a low cholesterol diet? Therapeutic lifestyle changes (TLC) includes a low cholesterol ...

  12. LDL: The "Bad" Cholesterol

    Science.gov (United States)

    ... waxy, fat-like substance that's found in all the cells in your body. Your liver makes cholesterol, ... stands for low-density lipoproteins. It is called the "bad" cholesterol because a high LDL level leads ...

  13. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles.

    Science.gov (United States)

    Nirala, Narsingh R; Saxena, Preeti S; Srivastava, Anchal

    2018-02-05

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles

    Science.gov (United States)

    Nirala, Narsingh R.; Saxena, Preeti S.; Srivastava, Anchal

    2018-02-01

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2 mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19 mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100 mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel.

  15. Cholesterol oxides inhibit cholesterol esterification by lecithin: cholesterol acyl transferase

    Directory of Open Access Journals (Sweden)

    Eder de Carvalho Pincinato

    2009-09-01

    Full Text Available Cholesterol oxides are atherogenic and can affect the activity of diverse important enzymes for the lipidic metabolism. The effect of 7β-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol, cholestan-3β,5α,6β-triol,5,6β-epoxycholesterol, 5,6α-epoxycholesterol and 7α-hydroxycholesterol on esterification of cholesterol by lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43 and the transfer of esters of cholesterol oxides from high density lipoprotein (HDL to low density lipoproteins (LDL and very low density lipoproteins (VLDL by cholesteryl ester transfer protein (CETP was investigated. HDL enriched with increasing concentrations of cholesterol oxides was incubated with fresh plasma as source of LCAT. Cholesterol and cholesterol oxides esterification was followed by measuring the consumption of respective free sterol and oxysterols. Measurements of cholesterol and cholesterol oxides were done by gas-chromatography. 14C-cholesterol oxides were incorporated into HDL2 and HDL3 subfractions and then incubated with fresh plasma containing LCAT and CETP. The transfer of cholesterol oxide esters was followed by measuring the 14C-cholesterol oxide-derived esters transferred to LDL and VLDL. All the cholesterol oxides studied were esterified by LCAT after incorporation into HDL particles, competing with cholesterol by LCAT. Cholesterol esterification by LCAT was inversely related to the cholesterol oxide concentration. The esterification of 14C-cholesterol oxides was higher in HDL3 and the transfer of the derived esters was greater from HDL2 to LDL and VLDL. The results suggest that cholesterol esterification by LCAT is inhibited in cholesterol oxide-enriched HDL particles. Moreover, the cholesterol oxides-derived esters are efficiently transferred to LDL and VLDL. Therefore, we suggest that cholesterol oxides may exert part of their atherogenic effect by inhibiting cholesterol esterification on the HDL surface and thereby disturbing

  16. What Your Cholesterol Levels Mean

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More What Your Cholesterol Levels Mean Updated:Nov 16,2017 Keeping your ... stroke. This content was last reviewed April 2017. Cholesterol • Home • About Cholesterol Introduction Atherosclerosis What Your Cholesterol ...

  17. Home-Use Tests - Cholesterol

    Science.gov (United States)

    ... Medical Procedures In Vitro Diagnostics Home Use Tests Cholesterol Share Tweet Linkedin Pin it More sharing options ... a home-use test kit to measure total cholesterol. What cholesterol is: Cholesterol is a fat (lipid) ...

  18. In type 2 diabetes mellitus glycated albumin alters macrophage gene expression impairing ABCA1-mediated cholesterol efflux.

    Science.gov (United States)

    Machado-Lima, Adriana; Iborra, Rodrigo T; Pinto, Raphael S; Castilho, Gabriela; Sartori, Camila H; Oliveira, Erika R; Okuda, Ligia S; Nakandakare, Edna R; Giannella-Neto, Daniel; Machado, Ubiratan F; Corrêa-Giannella, Maria Lucia C; Traldi, Pietro; Porcu, Simona; Roverso, Marco; Lapolla, Annunziata; Passarelli, Marisa

    2015-06-01

    Advanced glycation end products (AGE) are elevated in diabetes mellitus (DM) and predict the development of atherosclerosis. AGE-albumin induces oxidative stress, which is linked to a reduction in ABCA-1 and cholesterol efflux. We characterized the glycation level of human serum albumin (HSA) isolated from poorly controlled DM2 (n = 11) patients compared with that of control (C, n = 12) individuals and determined the mechanism by which DM2-HSA can interfere in macrophage lipid accumulation. The HSA glycation level was analyzed by MALDI/MS. Macrophages were treated for 18 h with C- or DM2-HSA to measure the (14) C-cholesterol efflux, the intracellular lipid accumulation and the cellular ABCA-1 protein content. Agilent arrays (44000 probes) were used to analyze gene expression, and the differentially expressed genes were validated by real-time RT-PCR. An increased mean mass was observed in DM2-HSA compared with C-HSA, reflecting the condensation of at least 5 units of glucose. The cholesterol efflux mediated by apo AI, HDL3 , and HDL2 was impaired in DM2-HSA-treated cells, which was related to greater intracellular lipid accumulation. DM2-HSA decreased Abcg1 mRNA expression by 26%. Abca1 mRNA was unchanged, although the final ABCA-1 protein content decreased. Compared with C-HAS-treated cells, NADPH oxidase 4 mRNA expression increased in cells after DM2-HSA treatment. Stearoyl-Coenzyme A desaturase 1, janus kinase 2, and low density lipoprotein receptor mRNAs were reduced by DM2-HSA. The level of glycation that occurs in vivo in DM2-HSA-treated cells selectively alters macrophage gene expression, impairing cholesterol efflux and eliciting intracellular lipid accumulation, which contribute to atherogenesis, in individuals with DM2. © 2014 Wiley Periodicals, Inc.

  19. Relationship between serum cholesterol and body mass index in Nigeria schoolchildren aged 2-15 years.

    Science.gov (United States)

    Nwaiwu, Obiyo; Ibe, Bede C

    2015-04-01

    Non-communicable disease is becoming a public health problem that it is already present in more affluent countries. The aim of this study was to determine the relationship between body mass index (BMI) and total serum cholesterol with its lipoprotein fractions in children aged 2-15 years. Serum cholesterol was estimated using the enzymatic spectrophotometer cholesterol oxidase/peroxidase method. BMI was calculated as weight (kg)/height (m(2)). Total cholesterol and low-density lipoprotein were positively co-related with BMI (p cholesterol from known BMI values were developed. There is a positive correlation between BMI and serum cholesterol. BMI which is non-invasive is recommended as a screening tool for cardiovascular risk in settings where serum cholesterol cannot be routinely estimated. © The Author [2015]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Lysyl oxidase and the lysyl oxidase-like protein modulate odontoblastic differentiation of human dental pulp cells.

    Science.gov (United States)

    Kim, Eun-Cheol; Lee, Hwa-Jeong; Kim, Youngho

    2012-06-01

    The lysyl oxidase (LOX) family is an emerging family of amine oxidases responsible for the formation of collagen fibrils in the extracellular matrix. To date, 5 LOX family genes have been identified in humans, encoding LOX and LOX-like proteins (LOXL, LOXL2, LOXL3, and LOXL4). The goal of this study was to evaluate the expression and function of the LOX family genes in odontoblastic differentiation of human dental pulp (HDP) cells. Expression of the LOX family genes was assessed by reverse transcriptase polymerase chain reaction analysis, and the amine oxidase activity of HDP cells was evaluated by peroxidase-coupled fluorometric assays. Mineral nodule formation and expression of odontoblastic marker genes were assessed in the presence and absence of specific small interfering RNAs (siRNAs) of the LOX family genes. Among the LOX family genes, only LOX and LOXL showed prominent expression during odontoblastic differentiation of HDP cells. Suppression of LOX and LOXL expression by siRNA-induced interference substantially decreased the amine oxidase activity of the differentiating HDP cells. Furthermore, interference of LOX and LOXL expression inhibited mineral nodule formation and expression of odontoblastic marker genes during odontoblastic differentiation of HDP cells. These findings show for the first time that the LOX- and LOXL-mediated organization of collagen fibrils in extracellular matrices of HDP cells might be an important regulator for odontoblastic differentiation of HDP cells. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Enzymatic oxidation of cholesterol: properties and functional effects of cholestenone in cell membranes.

    Directory of Open Access Journals (Sweden)

    Maarit Neuvonen

    Full Text Available Bacterial cholesterol oxidase is commonly used as an experimental tool to reduce cellular cholesterol content. That the treatment also generates the poorly degradable metabolite 4-cholesten-3-one (cholestenone has received less attention. Here, we investigated the membrane partitioning of cholestenone using simulations and cell biological experiments and assessed the functional effects of cholestenone in human cells. Atomistic simulations predicted that cholestenone reduces membrane order, undergoes faster flip-flop and desorbs more readily from membranes than cholesterol. In primary human fibroblasts, cholestenone was released from membranes to physiological extracellular acceptors more avidly than cholesterol, but without acceptors it remained in cells over a day. To address the functional effects of cholestenone, we studied fibroblast migration during wound healing. When cells were either cholesterol oxidase treated or part of cellular cholesterol was exchanged for cholestenone with cyclodextrin, cell migration during 22 h was markedly inhibited. Instead, when a similar fraction of cholesterol was removed using cyclodextrin, cells replenished their cholesterol content in 3 h and migrated similarly to control cells. Thus, cholesterol oxidation produces long-term functional effects in cells and these are in part due to the generated membrane active cholestenone.

  2. Cholesterol modulates open probability and desensitization of NMDA receptors

    Science.gov (United States)

    Korinek, Miloslav; Vyklicky, Vojtech; Borovska, Jirina; Lichnerova, Katarina; Kaniakova, Martina; Krausova, Barbora; Krusek, Jan; Balik, Ales; Smejkalova, Tereza; Horak, Martin; Vyklicky, Ladislav

    2015-01-01

    NMDA receptors (NMDARs) are glutamate-gated ion channels that mediate excitatory neurotransmission in the CNS. Although these receptors are in direct contact with plasma membrane, lipid–NMDAR interactions are little understood. In the present study, we aimed at characterizing the effect of cholesterol on the ionotropic glutamate receptors. Whole-cell current responses induced by fast application of NMDA in cultured rat cerebellar granule cells (CGCs) were almost abolished (reduced to 3%) and the relative degree of receptor desensitization was increased (by seven-fold) after acute cholesterol depletion by methyl-β-cyclodextrin. Both of these effects were fully reversible by cholesterol repletion. By contrast, the responses mediated by AMPA/kainate receptors were not affected by cholesterol depletion. Similar results were obtained in CGCs after chronic inhibition of cholesterol biosynthesis by simvastatin and acute enzymatic cholesterol degradation to 4-cholesten-3-one by cholesterol oxidase. Fluorescence anisotropy measurements showed that membrane fluidity increased after methyl-β-cyclodextrin pretreatment. However, no change in fluidity was observed after cholesterol enzymatic degradation, suggesting that the effect of cholesterol on NMDARs is not mediated by changes in membrane fluidity. Our data show that diminution of NMDAR responses by cholesterol depletion is the result of a reduction of the open probability, whereas the increase in receptor desensitization is the result of an increase in the rate constant of entry into the desensitized state. Surface NMDAR population, agonist affinity, single-channel conductance and open time were not altered in cholesterol-depleted CGCs. The results of our experiments show that cholesterol is a strong endogenous modulator of NMDARs. Key points NMDA receptors (NMDARs) are tetrameric cation channels permeable to calcium; they mediate excitatory synaptic transmission in the CNS and their excessive activation can lead to

  3. Mitochondrial cholesterol import.

    Science.gov (United States)

    Elustondo, Pia; Martin, Laura A; Karten, Barbara

    2017-01-01

    All animal subcellular membranes require cholesterol, which influences membrane fluidity and permeability, fission and fusion processes, and membrane protein function. The distribution of cholesterol among subcellular membranes is highly heterogeneous and the cholesterol content of each membrane must be carefully regulated. Compared to other subcellular membranes, mitochondrial membranes are cholesterol-poor, particularly the inner mitochondrial membrane (IMM). As a result, steroidogenesis can be controlled through the delivery of cholesterol to the IMM, where it is converted to pregnenolone. The low basal levels of cholesterol also make mitochondria sensitive to changes in cholesterol content, which can have a relatively large impact on the biophysical and functional characteristics of mitochondrial membranes. Increased mitochondrial cholesterol levels have been observed in diverse pathological conditions including cancer, steatohepatitis, Alzheimer disease and Niemann-Pick Type C1-deficiency, and are associated with increased oxidative stress, impaired oxidative phosphorylation, and changes in the susceptibility to apoptosis, among other alterations in mitochondrial function. Mitochondria are not included in the vesicular trafficking network; therefore, cholesterol transport to mitochondria is mostly achieved through the activity of lipid transfer proteins at membrane contact sites or by cytosolic, diffusible lipid transfer proteins. Here we will give an overview of the main mechanisms involved in mitochondrial cholesterol import, focusing on the steroidogenic acute regulatory protein StAR/STARD1 and other members of the StAR-related lipid transfer (START) domain protein family, and we will discuss how changes in mitochondrial cholesterol levels can arise and affect mitochondrial function. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Electrochemical oxidation of cholesterol

    Directory of Open Access Journals (Sweden)

    Jacek W. Morzycki

    2015-03-01

    Full Text Available Indirect cholesterol electrochemical oxidation in the presence of various mediators leads to electrophilic addition to the double bond, oxidation at the allylic position, oxidation of the hydroxy group, or functionalization of the side chain. Recent studies have proven that direct electrochemical oxidation of cholesterol is also possible and affords different products depending on the reaction conditions.

  5. National Cholesterol Education Month

    Centers for Disease Control (CDC) Podcasts

    2009-09-01

    Do you know your cholesterol numbers? Your doctor can do a simple test to check your cholesterol levels and help you make choices that lower your risk for heart disease and stroke.  Created: 9/1/2009 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 9/9/2009.

  6. Cholesterol and Health

    Indian Academy of Sciences (India)

    cholesterol. In the gall bladder cholesterol crystalizes from the bile producing large crystalline aggregates. The causes of gall- stones are too complex for us to go into, but it can be stated that such factors as high levels of estrogens, multiple pregnancies, obesity, genetic factors and certain drugs influence the degree to.

  7. Phosphatidylcholine: cholesterol phase diagrams.

    Science.gov (United States)

    Thewalt, J L; Bloom, M

    1992-10-01

    Two mono-cis-unsaturated phosphatidylcholine (PC) lipid molecules, having very different gel-liquid crystalline phase transition temperatures as a consequence of the relative positions of the double bond, exhibit PC:cholesterol phase diagrams that are very similar to each other and to that obtained previously for a fully saturated PC:cholesterol mixture (Vist, M. R., and J. H. Davis. 1990. Biochemistry 29:451-464). This leads to the conjecture that PC:cholesterol membrane phase diagrams have a universal form which is relatively independent of the precise chemical structure of the PC molecule. One feature of this phase diagram is the observation over a wide temperature range of a fluid but highly conformationally ordered phase at bilayer concentrations of more than approximately 25 mol% cholesterol. This ;liquid ordered' phase is postulated to be the relevant physical state for many biological membranes, such as the plasma membrane of eukaryotic cells, that contain substantial amounts of cholesterol or equivalent sterols.

  8. Bile acid sequestrants for cholesterol

    Science.gov (United States)

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  9. Regulation of cholesterol homeostasis

    NARCIS (Netherlands)

    van der Wulp, Mariette Y. M.; Verkade, Henkjan J.; Groen, Albert K.

    2013-01-01

    Hypercholesterolemia is an important risk factor for cardiovascular disease. It is caused by a disturbed balance between cholesterol secretion into the blood versus uptake. The pathways involved are regulated via a complex interplay of enzymes, transport proteins, transcription factors and

  10. High Blood Cholesterol

    Science.gov (United States)

    ... cholesterol or other fats, such as triglycerides. Total testosterone and dehydroepiandrosterone sulphate tests can help rule out ... Intramural Research , which includes investigators in our Lipoprotein Metabolism Laboratory , is actively engaged in the study of ...

  11. Cholesterol - drug treatment

    Science.gov (United States)

    ... disease Heart attack Heart bypass surgery Heart bypass surgery - minimally invasive Heart disease and diet High blood cholesterol levels Peripheral artery bypass - leg Patient Instructions Abdominal aortic aneurysm repair - open - discharge Angina - discharge Angina - ...

  12. Cholesterol Domains Enhance Transfection

    Science.gov (United States)

    Betker, Jamie L.; Kullberg, Max; Gomez, Joe; Anchordoquy, Thomas J.

    2014-01-01

    The formation of cholesterol domains in lipoplexes has been associated with enhanced serum stability and transfection rates both in cell culture and in vivo. This study utilizes the ability of saturated phosphatidylcholines to promote the formation of cholesterol domains at much lower cholesterol contents than have been utilized in previous work. The results show that lipoplexes with identical cholesterol and cationic lipid contents exhibit significantly improved transfection efficiencies when a domain is present, consistent with previous work. In addition, studies assessing transfection rates in the absence of serum demonstrate that the ability of domains to enhance transfection is not dependent on interactions with serum proteins. Consistent with this hypothesis, characterization of the adsorbed proteins composing the corona of these lipoplex formulations did not reveal a correlation between transfection and the adsorption of a specific protein. Finally, we show that the interaction with serum proteins can promote domain formation in some formulations, and thereby result in enhanced transfection only after serum exposure. PMID:23557286

  13. High Blood Cholesterol Prevention

    Science.gov (United States)

    ... lots of foods high in saturated fat and trans fat may contribute to high cholesterol and related conditions, ... Choose foods that are low in saturated fat, trans fat, sodium (salt), and added sugars. These foods include ...

  14. Reference intervals for serum total cholesterol, HDL cholesterol and ...

    African Journals Online (AJOL)

    Reference intervals of total cholesterol, HDL cholesterol and non-HDL cholesterol concentrations were determined on 309 blood donors from an urban and peri-urban population of Botswana. Using non-parametric methods to establish 2.5th and 97.5th percentiles of the distribution, the intervals were: total cholesterol 2.16 ...

  15. Oxidases as Breast Cancer Oncogens

    National Research Council Canada - National Science Library

    Yeldandi, Anjana

    2000-01-01

    ...) in a non-tumorigenic human mammary epithelial cell line to ascertain whether oxidase overexpressing cells undergo transformation when exposed to substrate xanthine for XOX and uric acid for UOX...

  16. Lysyl oxidase in colorectal cancer

    DEFF Research Database (Denmark)

    Cox, Thomas R; Erler, Janine T

    2013-01-01

    Colorectal cancer is the third most prevalent form of cancer worldwide and fourth-leading cause of cancer-related mortality, leading to ~600,000 deaths annually, predominantly affecting the developed world. Lysyl oxidase is a secreted, extracellular matrix-modifying enzyme previously suggested...... to act as a tumor suppressor in colorectal cancer. However, emerging evidence has rapidly implicated lysyl oxidase in promoting metastasis of solid tumors and in particular colorectal cancer at multiple stages, affecting tumor cell proliferation, invasion, and angiogenesis. This emerging research has...... stimulated significant interest in lysyl oxidase as a strong candidate for developing and deploying inhibitors as functional efficacious cancer therapeutics. In this review, we discuss the rapidly expanding body of knowledge concerning lysyl oxidase in solid tumor progression, highlighting recent...

  17. Lysyl oxidase in colorectal cancer.

    Science.gov (United States)

    Cox, Thomas R; Erler, Janine T

    2013-11-15

    Colorectal cancer is the third most prevalent form of cancer worldwide and fourth-leading cause of cancer-related mortality, leading to ~600,000 deaths annually, predominantly affecting the developed world. Lysyl oxidase is a secreted, extracellular matrix-modifying enzyme previously suggested to act as a tumor suppressor in colorectal cancer. However, emerging evidence has rapidly implicated lysyl oxidase in promoting metastasis of solid tumors and in particular colorectal cancer at multiple stages, affecting tumor cell proliferation, invasion, and angiogenesis. This emerging research has stimulated significant interest in lysyl oxidase as a strong candidate for developing and deploying inhibitors as functional efficacious cancer therapeutics. In this review, we discuss the rapidly expanding body of knowledge concerning lysyl oxidase in solid tumor progression, highlighting recent advancements in the field of colorectal cancer.

  18. Cholesterol Balance in Prion Diseases and Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Samia Hannaoui

    2014-11-01

    Full Text Available Prion diseases are transmissible and fatal neurodegenerative disorders of humans and animals. They are characterized by the accumulation of PrPSc, an aberrantly folded isoform of the cellular prion protein PrPC, in the brains of affected individuals. PrPC is a cell surface glycoprotein attached to the outer leaflet of the plasma membrane by a glycosyl-phosphatidyl-inositol (GPI anchor. Specifically, it is associated with lipid rafts, membrane microdomains enriched in cholesterol and sphinoglipids. It has been established that inhibition of endogenous cholesterol synthesis disturbs lipid raft association of PrPC and prevents PrPSc accumulation in neuronal cells. Additionally, prion conversion is reduced upon interference with cellular cholesterol uptake, endosomal export, or complexation at the plasma membrane. Altogether, these results demonstrate on the one hand the importance of cholesterol for prion propagation. On the other hand, growing evidence suggests that prion infection modulates neuronal cholesterol metabolism. Similar results were reported in Alzheimer’s disease (AD: whereas amyloid β peptide formation is influenced by cellular cholesterol, levels of cholesterol in the brains of affected individuals increase during the clinical course of the disease. In this review, we summarize commonalities of alterations in cholesterol homeostasis and discuss consequences for neuronal function and therapy of prion diseases and AD.

  19. Cholesterol Balance in Prion Diseases and Alzheimer’s Disease

    Science.gov (United States)

    Hannaoui, Samia; Shim, Su Yeon; Cheng, Yo Ching; Corda, Erica; Gilch, Sabine

    2014-01-01

    Prion diseases are transmissible and fatal neurodegenerative disorders of humans and animals. They are characterized by the accumulation of PrPSc, an aberrantly folded isoform of the cellular prion protein PrPC, in the brains of affected individuals. PrPC is a cell surface glycoprotein attached to the outer leaflet of the plasma membrane by a glycosyl-phosphatidyl-inositol (GPI) anchor. Specifically, it is associated with lipid rafts, membrane microdomains enriched in cholesterol and sphinoglipids. It has been established that inhibition of endogenous cholesterol synthesis disturbs lipid raft association of PrPC and prevents PrPSc accumulation in neuronal cells. Additionally, prion conversion is reduced upon interference with cellular cholesterol uptake, endosomal export, or complexation at the plasma membrane. Altogether, these results demonstrate on the one hand the importance of cholesterol for prion propagation. On the other hand, growing evidence suggests that prion infection modulates neuronal cholesterol metabolism. Similar results were reported in Alzheimer’s disease (AD): whereas amyloid β peptide formation is influenced by cellular cholesterol, levels of cholesterol in the brains of affected individuals increase during the clinical course of the disease. In this review, we summarize commonalities of alterations in cholesterol homeostasis and discuss consequences for neuronal function and therapy of prion diseases and AD. PMID:25419621

  20. Respiratory burst oxidase of fertilization.

    Science.gov (United States)

    Heinecke, J W; Shapiro, B M

    1989-02-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation of egg activation modulate the activity of the oxidase. Inhibitors were used to test the relevance of this oxidase to the respiratory burst of fertilization. Procaine, two phenothiazines, and N-ethylmaleimide (but not iodoacetamide) inhibited H2O2 production by the oxidase fraction and oxygen consumption by activated eggs. The ATP requirement suggested that protein kinase activity might regulate the respiratory burst of fertilization; consonant with this hypothesis, H-7 and staurosporine were inhibitory. The respiratory burst oxidase of fertilization is an NADPH:O2 oxidoreductase that appears to be regulated by a protein kinase; although it bears a remarkable resemblance to the neutrophil oxidase, unlike the latter it does not form O2- as its initial product.

  1. Cholesterol through the Looking Glass

    Science.gov (United States)

    Kristiana, Ika; Luu, Winnie; Stevenson, Julian; Cartland, Sian; Jessup, Wendy; Belani, Jitendra D.; Rychnovsky, Scott D.; Brown, Andrew J.

    2012-01-01

    How cholesterol is sensed to maintain homeostasis has been explained by direct binding to a specific protein, Scap, or through altering the physical properties of the membrane. The enantiomer of cholesterol (ent-cholesterol) is a valuable tool in distinguishing between these two models because it shares nonspecific membrane effects with native cholesterol (nat-cholesterol), but not specific binding interactions. This is the first study to compare ent- and nat-cholesterol directly on major molecular parameters of cholesterol homeostasis. We found that ent-cholesterol suppressed activation of the master transcriptional regulator of cholesterol metabolism, SREBP-2, almost as effectively as nat-cholesterol. Importantly, ent-cholesterol induced a conformational change in the cholesterol-sensing protein Scap in isolated membranes in vitro, even when steps were taken to eliminate potential confounding effects from endogenous cholesterol. Ent-cholesterol also accelerated proteasomal degradation of the key cholesterol biosynthetic enzyme, squalene monooxygenase. Together, these findings provide compelling evidence that cholesterol maintains its own homeostasis not only via direct protein interactions, but also by altering membrane properties. PMID:22869373

  2. Influence of monoamine oxidase inhibitor on contractility of isolated rat hearts

    NARCIS (Netherlands)

    Meijler, F.L.; Durrer, D.

    1962-01-01

    Following the suggestion that monoamine oxidase inhibitor might interfere with potentiation of cardiac contractions, the influence of 1-iso-nicotinyl-2-isopropyl-hydrazide and 1-pivaloyl-2-benzyl-hydrazine on postextrasystolic increase of isotonic contractions in isolated perfused rat hearts was

  3. HDL cholesterol: atherosclerosis and beyond

    OpenAIRE

    Bochem, A.E.

    2013-01-01

    Cardiovascular disease (CVD) is the leading cause of death in the Western world. Myocardial infarction and stroke are the result of a compromised blood flow which may result from cholesterol accumulation in the vessel wall due to high plasma levels of LDL cholesterol. High plasma levels of HDL cholesterol, however, are inversely associated with CVD. This is commonly ascribed to a concept called "reverse cholesterol transport" a mechanism by which the HDL particle takes up cholesterol from the...

  4. IETS and quantum interference

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2014-01-01

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low...... suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference....

  5. An enzyme thermistor-based assay for total and free cholesterol.

    Science.gov (United States)

    Raghavan, V; Ramanathan, K; Sundaram, P V; Danielsson, B

    1999-11-01

    A method to evaluate the free (FC) and total cholesterol (TC) in human serum, bile and gallstone extract using an enzyme thermistor (ET)-based flow injection analysis (FIA) is presented. The cholesterol in high-density (HDL-C) and low density lipoprotein (LDL-C) have also been evaluated. A heparin functionalized Sepharose column was employed for the isolation of HDL and LDL fractions from serum. The estimation of cholesterol and its esters was based on their reaction with cholesterol oxidase (CO), cholesterol esterase (CE) and catalase (CAT). Three different enzyme columns, i.e. co-immobilized CO/CAT (column A), only CE (column B) and co-immobilized CO/CE/CAT (column C) were prepared by cross-linking the enzymes on glass beads using glutaraldehyde. Column A was used for estimating FC and column C was used for estimating total cholesterol (cholesterol plus esterified cholesterol). Column B was used as a pre-column which could be switched 'in' or 'out' in conjunction with column A for the estimation of TC or FC, respectively. A calibration between 1.0 and 8.0 mmol/l for FC and 0. 25 and 4.0 mmol/l for TC was obtained. For more than 2000 assays with the ET device a C.V. of less than 4% was obtained. The assay time was approximately 4 min per assay. The cholesterol estimations on the ET correlated well with similar estimations using a commercially available cholesterol diagnostic kit.

  6. Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Koji Sode

    2012-11-01

    Full Text Available Mutagenesis studies on glucose oxidases (GOxs were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe and Aspergillus niger GOx (PDB ID; 1cf3. We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

  7. Cholesterol and Health

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 2. Cholesterol and Health. Pravina Piste Vidyadhar Patil. General Article Volume 11 Issue 2 February 2006 pp 74-77. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/011/02/0074-0077. Keywords.

  8. Cost-effective and highly sensitive cholesterol microsensors with fast response based on the enzyme-induced conductivity change of polyaniline

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Kuan-Chung; Chu, Chia-Ho; Hsu, Chen-Pin; Kang, Yen-Wen; Fang, Jung-Ying; Chen, Chih-Chen; Li, Sheng-Shian; Andrew Yeh, J.; Yao, Da-Jeng; Wang, Yu-Lin, E-mail: ylwang@mx.nthu.edu.tw [Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 300, Taiwan (China); Hsu, Chia-Hsien [Division of Medical Engineering, National Health Research Institutes, MiaoLi, Taiwan (China); Huang, Yu-Fen [Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2014-09-15

    In this study, a cost-effective and highly sensitive cholesterol microsensor, which is consisted of cholesterol oxidase (ChOx), horseradish peroxidase (HRP), and polyaniline (PANI), was developed based on the enzyme-induced conductivity change of PANI with fast response. Hydrogen peroxide is produced via the reaction between cholesterol and ChOx, which was immobilized in a dialysis membrane. The produced hydrogen peroxide can oxidize HRP, which can be reduced by oxidizing PANI, thus resulting in decreased conductivity of the polyaniline thin film. The reduced HRP can be oxidized again by hydrogen peroxide and the cycle of the oxidation/reduction continues until all hydrogen peroxide are reacted, leading to the high sensitivity of the sensor due to the signal contributed from all hydrogen peroxide molecules. Cholesterol was detected near the physiological concentrations ranging from 100 mg/dl to 400 mg/dl with the cholesterol microsensors. The results show linear relation between cholesterol concentration and the conductivity change of the PANI. The microsensor showed no response to cholesterol when the PANI was standalone without cholesterol oxidase immobilized, indicating that the enzymatic reaction is required for cholesterol detection. The simple process of the sensor fabrication allows the sensor to be cost-effective and disposable usage. This electronic cholesterol microsensor is promising for point-of-care health monitoring in cholesterol level with low cost and fast response.

  9. Amperometric cholesterol biosensors based on the electropolymerization of pyrrole and aniline in sulphuric Acid for the determination of cholesterol in serum.

    Science.gov (United States)

    Muhammet, Sinan M; Cete, Servet; Arslan, Fatma; Yaşar, Ahmet

    2009-01-01

    A new amperometric cholesterol biosensor was prepared by immobilizing cholesterol oxidase by a glutaraldehyde crosslinking procedure on polypyrrole-polyaniline (ppy-pani) composite film on the surface of a platinum electrode. In order to prepare a biosensor for the determination of cholesterol, electropolymerization of pyrrole and aniline on Pt surface was performed with an electrochemical cell containing pyrrole and aniline in sulphuric acid by cyclic voltammetry between 0.0 and 0,7 V (vs.Ag/AgCl) at a scan rate of 50 mV upon Pt electrode. The amperometric determination is based on the electrochemical detection of H(2)O(2), which is generated in enzymatic reaction of cholesterol. The cholesterol determined by the oxidation of enzymatically generated H(2)O(2) at 0.7 V vs. Ag/AgCl. The optimized cholesterol oxidase biosensor displayed linear working range and a response time of 300 s. The effects of pH and temperature were investigated and optimum parameters were found to be 7.0, 25 degrees C, respectively. In addition to this, the stability and reproducibility of biosensor were tried. Operational stability of the proposed cholesterol biosensor was obtained by periodical measurements of the biosensor response. Biosensor at optimum activity conditions was used in 30 activity assays in one day to determine the operational stability. The results show that 82% of the response current was retained after 30 activity assays. The electrode was stored in a refrigerator at 4 degrees C after the measurements. The storage stability of the biosensor was determined by performing activity assays within 23 days. The results demonstrate that 60% of the response current was retained after 23 days. Preparing biosensor is used for the analysis of cholesterol in serum.

  10. Flavoprotein oxidases : classification and applications

    NARCIS (Netherlands)

    Dijkman, Willem P.; de Gonzalo, Gonzalo; Mattevi, Andrea; Fraaije, Marco W.

    This review provides an overview of oxidases that utilise a flavin cofactor for catalysis. This class of oxidative flavoenzymes has shown to harbour a large number of biotechnologically interesting enzymes. Applications range from their use as biocatalysts for the synthesis of pharmaceutical

  11. A novel function for lysyl oxidase in pluripotent mesenchymal cell proliferation and relevance to inflammation-associated osteopenia.

    Science.gov (United States)

    Khosravi, Roozbeh; Sodek, Katharine L; Xu, Wan-Peng; Bais, Manish V; Saxena, Debashree; Faibish, Michael; Trackman, Philip C

    2014-01-01

    Lysyl oxidase is a multifunctional enzyme required for collagen biosynthesis. Various growth factors regulate lysyl oxidase during osteoblast differentiation, subject to modulation by cytokines such as TNF-α in inflammatory osteopenic disorders including diabetic bone disease. Canonical Wnt signaling promotes osteoblast development. Here we investigated the effect of Wnt3a and TNF-α on lysyl oxidase expression in pluripotent C3H10T1/2 cells, bone marrow stromal cells, and committed osteoblasts. Lysyl oxidase was up-regulated by a transcriptional mechanism 3-fold in C3H10T1/2 cells, and 2.5-fold in bone marrow stromal cells. A putative functional TCF/LEF element was identified in the lysyl oxidase promoter. Interestingly, lysyl oxidase was not up-regulated in committed primary rat calvarial- or MC3T3-E1 osteoblasts. TNF-α down-regulated lysyl oxidase both in Wnt3a-treated and in non-treated C3H10T1/2 cells by a post-transcriptional mechanism mediated by miR203. Non-differentiated cells do not produce a collagen matrix; thus, a novel biological role for lysyl oxidase in pluripotent cells was investigated. Lysyl oxidase shRNAs effectively silenced lysyl oxidase expression, and suppressed the growth of C3H10T1/2 cells by 50%, and blocked osteoblast differentiation. We propose that interference with lysyl oxidase expression under excess inflammatory conditions such as those that occur in diabetes, osteoporosis, or rheumatoid arthritis can result in a diminished pool of pluripotent cells which ultimately contributes to osteopenia.

  12. A novel function for lysyl oxidase in pluripotent mesenchymal cell proliferation and relevance to inflammation-associated osteopenia.

    Directory of Open Access Journals (Sweden)

    Roozbeh Khosravi

    Full Text Available Lysyl oxidase is a multifunctional enzyme required for collagen biosynthesis. Various growth factors regulate lysyl oxidase during osteoblast differentiation, subject to modulation by cytokines such as TNF-α in inflammatory osteopenic disorders including diabetic bone disease. Canonical Wnt signaling promotes osteoblast development. Here we investigated the effect of Wnt3a and TNF-α on lysyl oxidase expression in pluripotent C3H10T1/2 cells, bone marrow stromal cells, and committed osteoblasts. Lysyl oxidase was up-regulated by a transcriptional mechanism 3-fold in C3H10T1/2 cells, and 2.5-fold in bone marrow stromal cells. A putative functional TCF/LEF element was identified in the lysyl oxidase promoter. Interestingly, lysyl oxidase was not up-regulated in committed primary rat calvarial- or MC3T3-E1 osteoblasts. TNF-α down-regulated lysyl oxidase both in Wnt3a-treated and in non-treated C3H10T1/2 cells by a post-transcriptional mechanism mediated by miR203. Non-differentiated cells do not produce a collagen matrix; thus, a novel biological role for lysyl oxidase in pluripotent cells was investigated. Lysyl oxidase shRNAs effectively silenced lysyl oxidase expression, and suppressed the growth of C3H10T1/2 cells by 50%, and blocked osteoblast differentiation. We propose that interference with lysyl oxidase expression under excess inflammatory conditions such as those that occur in diabetes, osteoporosis, or rheumatoid arthritis can result in a diminished pool of pluripotent cells which ultimately contributes to osteopenia.

  13. Cholesterol binding to ion channels

    Directory of Open Access Journals (Sweden)

    Irena eLevitan

    2014-02-01

    Full Text Available Numerous studies demonstrated that membrane cholesterol is a major regulator of ion channel function. The goal of this review is to discuss significant advances that have been recently achieved in elucidating the mechanisms responsible for cholesterol regulation of ion channels. The first major insight that comes from growing number of studies that based on the sterol specificity of cholesterol effects, show that several types of ion channels (nAChR, Kir, BK, TRPV are regulated by specific sterol-protein interactions. This conclusion is supported by demonstrating direct saturable binding of cholesterol to a bacterial Kir channel. The second major advance in the field is the identification of putative cholesterol binding sites in several types of ion channels. These include sites at locations associated with the well-known cholesterol binding motif CRAC and its reversed form CARC in nAChR, BK, and TRPV, as well as novel cholesterol binding regions in Kir channels. Notably, in the majority of these channels, cholesterol is suggested to interact mainly with hydrophobic residues in non-annular regions of the channels being embedded in between transmembrane protein helices. We also discuss how identification of putative cholesterol binding sites is an essential step to understand the mechanistic basis of cholesterol-induced channel regulation. Clearly, however, these are only the first few steps in obtaining a general understanding of cholesterol-ion channels interactions and their roles in cellular and organ functions.

  14. Respiratory burst oxidase of fertilization.

    OpenAIRE

    Heinecke, J W; Shapiro, B M

    1989-01-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation...

  15. Lysyl oxidase in cancer research

    DEFF Research Database (Denmark)

    Perryman, Lara; Erler, Janine Terra

    2014-01-01

    Metastasis is the main reason for cancer-associated deaths and therapies are desperately needed to target the progression of cancer. Lysyl oxidase (LOX) plays a pivotal role in cancer progression, including metastasis, and is therefore is an attractive therapeutic target. In this review we...... will breakdown the process of cancer progression and the various roles that LOX plays has in the advancement of cancer. We will highlight why LOX is an exciting therapeutic target for the future....

  16. Characterization of placental cholesterol transport

    DEFF Research Database (Denmark)

    Lindegaard, Marie L; Wassif, Christopher A; Vaisman, Boris

    2008-01-01

    Patients with Smith-Lemli-Opitz syndrome (SLOS) are born with multiple congenital abnormalities. Postnatal cholesterol supplementation is provided; however, it cannot correct developmental malformations due to in utero cholesterol deficit. Increased transport of cholesterol from maternal to fetal...... circulation might attenuate congenital malformations. The cholesterol transporters Abca1, Abcg1, and Sr-b1 are present in placenta; however, their potential role in placental transport remains undetermined. In mice, expression analyses showed that Abca1 and Abcg1 transcripts increased 2-3-fold between...... embryonic days 13.5 and 18.5 in placental tissue; whereas, Sr-b1 expression decreased. To examine the functional role of Abca1, Abcg1 and Sr-b1 we measured the maternal-fetal transfer of (14)C-cholesterol in corresponding mutant embryos. Disruption of either Abca1 or Sr-b1 decreased cholesterol transfer...

  17. Conducted interference, challenges and interference cases

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2015-01-01

    Conducted interference has become increasingly problematic in the past few years, especially within the 2-150 kHz band. The high penetration of non-linear loads, combined with distributed generation, will influence the voltage profile, i.e. the power quality. New technologies will introduce new

  18. Recent advances in cholesterol chemistry.

    Science.gov (United States)

    Morzycki, Jacek W

    2014-05-01

    This review article presents advances in cholesterol chemistry since 2000. Various transformations (chemical, enzymatic, electrochemical, etc.) of cholesterol are presented. A special emphasis is given to cholesterol oxidation reactions, but also substitution of the 3β-hydroxyl group, addition to the C5-C6 double bond, C-H functionalization, and C-C bond forming reactions are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Dark Matter Interference

    DEFF Research Database (Denmark)

    Del Nobile, Eugenio; Kouvaris, Christoforos; Sannino, Francesco

    2012-01-01

    We study different patterns of interference in WIMP-nuclei elastic scattering that can accommodate the DAMA and CoGeNT experiments via an isospin violating ratio $f_n/f_p=-0.71$. We study interference between the following pairs of mediators: Z and Z', Z' and Higgs, and two Higgs fields. We show ...

  20. Quantum Interference of Molecules

    Indian Academy of Sciences (India)

    IAS Admin

    GENERAL │ ARTICLE. Quantum Interference of Molecules. Probing the Wave Nature of Matter. Anu Venugopalan. Keywords. Matter waves, wave-particle du- ality, electron interference, decoherence. Anu Venugopalan is on the faculty of the School of. Basic and Applied. Sciences, GGS. Indraprastha University,. Delhi.

  1. Laparoscopic sleeve gastrectomy modifies cholesterol synthesis but not cholesterol absorption.

    Science.gov (United States)

    De Vuono, S; Ricci, M A; Siepi, D; Boni, M; Gentili, A; Scavizzi, M; Daviddi, G; Labate, P; Roscini, A R; Lupattelli, G

    Each bariatric surgery procedure impacts differently on cholesterol synthesis and absorption. Although a restrictive procedure, sleeve gastrectomy resolves diabetes mellitus and, like mixed-type procedures, induces early changes in gastrointestinal hormones. To our knowledge the present study is the first to assess the effects of sleeve gastrectomy on cholesterol synthesis and absorption. 42 consecutive subjects with obesity and sleeve gastrectomy candidates were included in the study together with a control group of 20 subjects without obesity. Before sleeve gastrectomy and 10 months afterwards, all subjects underwent a clinical examination, blood tests, ultrasound visceral fat area estimation and determination of plasma lathosterol, campesterol and sitosterol concentrations. After sleeve gastrectomy, significant decreases were observed in BMI, waist circumference, visceral and subcutaneous fat, blood pressure, triglycerides, insulin and glucose levels, lathosterol and HOMA-IR. HDL-C and apolipoprotein AI levels increased significantly. No significant differences emerged in LDL-C, apolipoprotein B levels or cholesterol absorption markers. Lathosterol levels correlated significantly with BMI, visceral fat area and HOMA-IR. Differences in cholesterol intake after surgery were not significantly associated with differences in lathosterol, campesterol and sitosterol concentrations. Sleeve gastrectomy reduced the markers of cholesterol synthesis but did not modify cholesterol absorption. Changes in cholesterol synthesis and absorption were independent of variations in cholesterol intake, suggesting a specific sleeve gastrectomy-related effect. Copyright © 2016 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

  2. [The real measurement of non-HDL-cholesterol: Atherogenic cholesterol].

    Science.gov (United States)

    Millán, Jesús; Hernández-Mijares, Antonio; Ascaso, Juan F; Blasco, Mariano; Brea, Angel; Díaz, Ángel; González-Santos, Pedro; Mantilla, Teresa; Pedro-Botet, Juan; Pintó, Xavier

    Lowe density lipoproteins (LDL) are the causal agent of cardiovascular diseases. In practice, we identify LDL with cholesterol transported in LDL (cLDL). So, cLDL has become the major target for cardiovascular prevention. Howewer, we have progressive evidences about the role of triglycerides rich lipoproteins, particularly those very low density lipoprotein (VLDL) in promotion and progression of atherosclerosis, that leads cholesterol in VLDL and its remanents as a potential therapeutic target. This feature is particularly important and of a great magnitude, in patients with hypertiglyceridemia. We can to considere, that the non-HDL cholesterol -cLDL+cVLDL+c-remmants+Lp(a)- is the real measurement of atherogenic cholesterol. In addition, non-HDL-cholesterol do not show any variations between postprandial states. In fact, non-HDL-cholesterol should be an excellent marker of atherogenic cholesterol, and an major therapeutic target in patients with atherogenic dyslipidaemia. According with different clinical trials and with the epidemiological and mendelian studies, in patients with high cardiovascular risk, optimal level of cLDL will be under 70mg/dl, and under 100 ng/dl for non-HDL-cholesterol; and in high risk patients, 100mg/dl and 130mg/dl, respectively. Copyright © 2016. Publicado por Elsevier España, S.L.U.

  3. Electron and proton transport by NADPH oxidases

    OpenAIRE

    Demaurex, Nicolas; Petheö, Gábor L

    2005-01-01

    The NADPH oxidase is the main weapon of phagocytic white blood cells that are the first line of defence of our body against invading pathogens, and patients lacking a functional oxidase suffer from severe and recurrent infections. The oxidase is a multisubunit enzyme complex that transports electrons from cytoplasmic NADPH to molecular oxygen in order to generate superoxide free radicals. Electron transport across the plasma membrane is electrogenic and is associated with the flux of protons ...

  4. HDL cholesterol: atherosclerosis and beyond

    NARCIS (Netherlands)

    Bochem, A.E.

    2013-01-01

    Cardiovascular disease (CVD) is the leading cause of death in the Western world. Myocardial infarction and stroke are the result of a compromised blood flow which may result from cholesterol accumulation in the vessel wall due to high plasma levels of LDL cholesterol. High plasma levels of HDL

  5. Membrane cholesterol oxidation in live cells enhances the function of serotonin1Areceptors.

    Science.gov (United States)

    Jafurulla, Md; Nalli, Aswan; Chattopadhyay, Amitabha

    2017-03-01

    The serotonin 1A (5-HT 1A ) receptor is an important neurotransmitter receptor that belongs to the G protein-coupled receptor (GPCR) family. It is implicated in a variety of cognitive and behavioral functions and serves as an important drug target for neuropsychiatric disorders such as anxiety and depression. Previous work from our laboratory has demonstrated that membrane cholesterol plays an important role in the function of the serotonin 1A receptor. Our earlier results highlighted several structural features of cholesterol essential for receptor function. In order to explore the importance of the hydroxyl group of cholesterol in the function of the serotonin 1A receptor, we utilized cholesterol oxidase to oxidize the hydroxyl group of cholesterol to keto group. Our results show that the oxidation of the hydroxyl group of cholesterol in live cells resulted in enhancement of agonist binding and G-protein coupling to the receptor with no appreciable change in overall membrane order. These results extend our understanding of the structural requirements of cholesterol for receptor function. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Epigenetic Regulation of Cholesterol Homeostasis

    Directory of Open Access Journals (Sweden)

    Steve eMeaney

    2014-09-01

    Full Text Available Although best known as a risk factor for cardiovascular disease, cholesterol is a vital component of all mammalian cells. In addition to key structural roles, cholesterol is a vital biochemical precursor for numerous biologically important compounds including oxysterols and bile acids, as well as acting as an activator of critical morphogenic systems (e.g. the Hedgehog system. A variety of sophisticated regulatory mechanisms interact to coordinate the overall level of cholesterol in cells, tissues and the entire organism. Accumulating evidence indicates that in additional to the more ‘traditional’ regulatory schemes, cholesterol homeostasis is also under the control of epigenetic mechanisms such as histone acetylation and DNA methylation. The available evidence supporting a role for these mechanisms in the control of cholesterol synthesis, elimination, transport and storage are the focus of this review.

  7. Hepatitis C Virus Replication Depends on Endosomal Cholesterol Homeostasis.

    Science.gov (United States)

    Stoeck, Ina Karen; Lee, Ji-Young; Tabata, Keisuke; Romero-Brey, Inés; Paul, David; Schult, Philipp; Lohmann, Volker; Kaderali, Lars; Bartenschlager, Ralf

    2018-01-01

    Similar to other positive-strand RNA viruses, hepatitis C virus (HCV) causes massive rearrangements of intracellular membranes, resulting in a membranous web (MW) composed of predominantly double-membrane vesicles (DMVs), the presumed sites of RNA replication. DMVs are enriched for cholesterol, but mechanistic details on the source and recruitment of cholesterol to the viral replication organelle are only partially known. Here we focused on selected lipid transfer proteins implicated in direct lipid transfer at various endoplasmic reticulum (ER)-membrane contact sites. RNA interference (RNAi)-mediated knockdown identified several hitherto unknown HCV dependency factors, such as steroidogenic acute regulatory protein-related lipid transfer domain protein 3 (STARD3), oxysterol-binding protein-related protein 1A and -B (OSBPL1A and -B), and Niemann-Pick-type C1 (NPC1), all residing at late endosome and lysosome membranes and required for efficient HCV RNA replication but not for replication of the closely related dengue virus. Focusing on NPC1, we found that knockdown or pharmacological inhibition caused cholesterol entrapment in lysosomal vesicles concomitant with decreased cholesterol abundance at sites containing the viral replicase factor NS5A. In untreated HCV-infected cells, unesterified cholesterol accumulated at the perinuclear region, partially colocalizing with NS5A at DMVs, arguing for NPC1-mediated endosomal cholesterol transport to the viral replication organelle. Consistent with cholesterol being an important structural component of DMVs, reducing NPC1-dependent endosomal cholesterol transport impaired MW integrity. This suggests that HCV usurps lipid transfer proteins, such as NPC1, at ER-late endosome/lysosome membrane contact sites to recruit cholesterol to the viral replication organelle, where it contributes to MW functionality. IMPORTANCE A key feature of the replication of positive-strand RNA viruses is the rearrangement of the host cell

  8. Collectivity from interference

    Science.gov (United States)

    Blok, Boris; Jäkel, Christian D.; Strikman, Mark; Wiedemann, Urs Achim

    2017-12-01

    In hadronic collisions, interference between different production channels affects momentum distributions of multi-particle final states. As this QCD interference does not depend on the strong coupling constant α s , it is part of the no-interaction baseline that needs to be controlled prior to searching for other manifestations of collective dynamics, e.g., in the analysis of azimuthal anisostropy coefficients v n at the LHC. Here, we introduce a model that is based on the QCD theory of multi-parton interactions and that allows one to study interference effects in the production of m particles in hadronic collisions with N parton-parton interactions ("sources"). In an expansion in powers of 1/( N c 2 - 1) and to leading order in the number of sources N , we calculate interference effects in the m-particle spectra and we determine from them the second and fourth order cumulant momentum anisotropies v n {2} and v n {4}. Without invoking any azimuthal asymmetry and any density dependent non-linear dynamics in the incoming state, and without invoking any interaction in the final state, we find that QCD interference alone can give rise to values for v n {2} and v n {4}, n even, that persist unattenuated for increasing number of sources, that may increase with increasing multiplicity and that agree with measurements in proton-proton (pp) collisions in terms of the order of magnitude of the signal and the approximate shape of the transverse momentum dependence. We further find that the non-abelian features of QCD interference can give rise to odd harmonic anisotropies. These findings indicate that the no-interaction baseline including QCD interference effects can make a sizeable if not dominant contribution to the measured v n coefficients in pp collisions. Prospects for analyzing QCD interference contributions further and their possible relevance for proton-nucleus and nucleus-nucleus collisions are discussed shortly.

  9. The terminal oxidases of Paracoccus denitrificans

    NARCIS (Netherlands)

    de Gier, J.-W.; Lübben, M; Reijnders, W N; Tipker, C A; Slotboom, D.J.; van Spanning, R J; Stouthamer, A.H.; van der Oost, J.

    Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to

  10. The terminal oxidases of Paracoccus denitrificans

    NARCIS (Netherlands)

    Gier, Jan-Willem L. de; Lübben, Mathias; Reijnders, Willem N.M.; Tipker, Corinne A.; Slotboom, Dirk-Jan; Spanning, Rob J.M. van; Stouthamer, Adriaan H.; Oost, John van der

    1994-01-01

    Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to

  11. How to Get Your Cholesterol Tested

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More How To Get Your Cholesterol Tested Updated:Nov 16,2017 High cholesterol usually ... diabetes and high blood pressure. How often should cholesterol be checked? The American Heart Association recommends that ...

  12. Plasmonic optical interference.

    Science.gov (United States)

    Choi, Dukhyun; Shin, Chang Kyun; Yoon, Daesung; Chung, Deuk Seok; Jin, Yong Wan; Lee, Luke P

    2014-06-11

    Understanding optical interference is of great importance in fundamental and analytical optical design for next-generation personal, industrial, and military applications. So far, various researches have been performed for optical interference phenomena, but there have been no reports on plasmonic optical interference. Here, we report that optical interference could be effectively coupled with surface plasmons, resulting in enhanced optical absorption. We prepared a three-dimensional (3D) plasmonic nanostructure that consists of a plasmonic layer at the top, a nanoporous dielectric layer at the center, and a mirror layer at the bottom. The plasmonic layer mediates strong plasmonic absorption when the constructive interference pattern is matched with the plasmonic component. By tailoring the thickness of the dielectric layer, the strong plasmonic absorption can facilely be controlled and covers the full visible range. The plasmonic interference in the 3D nanostructure thus creates brilliant structural colors. We develop a design equation to determine the thickness of the dielectric layer in a 3D plasmonic nanostructure that could create the maximum absorption at a given wavelength. It is further demonstrated that the 3D plasmonic nanostructure can be realized on a flexible substrate. Our 3D plasmonic nanostructures will have a huge impact on the fields of optoelectronic systems, biochemical optical sensors, and spectral imaging.

  13. Characterization of catecholase and cresolase activities of eggplant polyphenol oxidase.

    Science.gov (United States)

    Pérez-Gilabert, M; García Carmona, F

    2000-03-01

    In the present paper the catecholase and cresolase activities of eggplant polyphenol oxidase (PPO) are described. To preserve the latter activity, a partially purified enzyme was used. Peroxidase was removed from the preparation to avoid its interference with PPO during phenol oxidation. The partially purified eggplant PPO was fully active. The catecholase/cresolase ratio of 41.1 indicated that, in a pH close to the physiological, diphenol oxidation predominates over monophenol oxidation. The characteristic lag phase of the cresolase activity is modulated by the pH, the monophenol and diphenol concentrations, and the enzyme's concentration. The effect of several inhibitors was also tested, and the K(i) values of the two most effective (tropolone and 4-hexylresorcinol) were determined.

  14. Nanomaterial-based Electrochemical Sensors for the Detection of Glucose and Cholesterol

    Science.gov (United States)

    Ahmadalinezhad, Asieh

    Electrochemical detection methods are highly attractive for the monitoring of glucose, cholesterol, cancer, infectious diseases, and biological warfare agents due to their low cost, high sensitivity, functionality despite sample turbidity, easy miniaturization via microfabrication, low power requirements, and a relatively simple control infrastructure. The development of implantable biosensors is laden with great challenges, which include longevity and inherent biocompatibility, coupled with the continuous monitoring of analytes. Deficiencies in any of these areas will necessitate their surgical replacement. In addition, random signals arising from non-specific adsorption events can cause problems in diagnostic assays. Hence, a great deal of effort has been devoted to the specific control of surface structures. Nanotechnology involves the creation and design of structures with at least one dimension that is below 100 nm. The optical, magnetic, and electrical properties of nanostructures may be manipulated by altering their size, shape, and composition. These attributes may facilitate improvements in biocompatibility, sensitivity and the specific attachment of biomaterials. Thus, the central theme of this dissertation pertains to highlighting the critical roles that are played by the morphology and intrinsic properties of nanomaterials when they are applied in the development of electrochemical biosensors. For this PhD project, we initially designed and fabricated a novel amperometric glucose biosensor based on the immobilization of glucose oxidase (GOx) on a Prussian blue modified nanoporous gold surface, which exhibited a rapid response and a low detection limit of 2.5 microM glucose. The sensitivity of the biosensor was found to be very high (177 microA/mM) and the apparent Michaelis--Menten constant was calculated to be 2.1 mM. Our study has demonstrated that nanoporous gold provides an excellent matrix for enzyme immobilization. To adopt these advanced

  15. Binaural Interference: Quo Vadis?

    Science.gov (United States)

    Jerger, James; Silman, Shlomo; Silverman, Carol; Emmer, Michele

    2017-04-01

    The reality of the phenomenon of binaural interference with speech recognition has been debated for two decades. Research has taken one of two avenues; group studies or case reports. In group studies, a sample of the elderly population is tested on speech recognition under three conditions; binaural, monaural right and monaural left. The aim is to determine the percent of the sample in which the expected outcome (binaural score-better-than-either-monaural score) is reversed (i.e., one of the monaural scores is better than the binaural score). This outcome has been commonly used to define binaural interference. The object of group studies is to answer the "how many" question, what is the prevalence of binaural interference in the sample. In case reports the binaural interference conclusion suggested by the speech recognition tests is not accepted until it has been corroborated by other independent diagnostic audiological measures. The aim is to attempt to determine the basis for the findings, to answer the "why" question. This article is at once tutorial, editorial and a case report. We argue that it is time to accept the reality of the phenomenon of binaural interference, to eschew group statistical approaches in search of an answer to the "how many" question, and to focus on individual case reports in search of an answer to the "why" question. American Academy of Audiology.

  16. Cholesterol worships a new idol.

    Science.gov (United States)

    Schulman, Ira G

    2009-12-01

    The growing worldwide epidemic of cardiovascular disease suggests that new therapeutic strategies are needed to complement statins in the lowering of cholesterol levels. In a recent paper in Science, Tontonoz and colleagues have identified Idol as a protein that can control cholesterol levels by regulating the stability of the low-density lipoprotein receptor; inhibiting the activity of Idol could provide novel approaches for the treatment of cardiovascular disease.

  17. A diminution in ascorbate oxidase activity affects carbon allocation and improves yield in tomato under water deficit.

    Science.gov (United States)

    Garchery, Cécile; Gest, Noé; Do, Phuc T; Alhagdow, Moftah; Baldet, Pierre; Menard, Guillaume; Rothan, Christophe; Massot, Capucine; Gautier, Hélène; Aarrouf, Jawad; Fernie, Alisdair R; Stevens, Rebecca

    2013-01-01

    The regulation of carbon allocation between photosynthetic source leaves and sink tissues in response to stress is an important factor controlling plant yield. Ascorbate oxidase is an apoplastic enzyme, which controls the redox state of the apoplastic ascorbate pool. RNA interference was used to decrease ascorbate oxidase activity in tomato (Solanum lycopersicum L.). Fruit yield was increased in these lines under three conditions where assimilate became limiting for wild-type plants: when fruit trusses were left unpruned, when leaves were removed or when water supply was limited. Several alterations in the transgenic lines could contribute to the improved yield and favour transport of assimilate from leaves to fruits in the ascorbate oxidase lines. Ascorbate oxidase plants showed increases in stomatal conductance and leaf and fruit sugar content, as well as an altered apoplastic hexose:sucrose ratio. Modifications in gene expression, enzyme activity and the fruit metabolome were coherent with the notion of the ascorbate oxidase RNAi lines showing altered sink strength. Ascorbate oxidase may therefore be a target for strategies aimed at improving water productivity in crop species. © 2012 Blackwell Publishing Ltd.

  18. Electron and proton transport by NADPH oxidases

    Science.gov (United States)

    Demaurex, Nicolas; Petheö, Gábor L

    2005-01-01

    The NADPH oxidase is the main weapon of phagocytic white blood cells that are the first line of defence of our body against invading pathogens, and patients lacking a functional oxidase suffer from severe and recurrent infections. The oxidase is a multisubunit enzyme complex that transports electrons from cytoplasmic NADPH to molecular oxygen in order to generate superoxide free radicals. Electron transport across the plasma membrane is electrogenic and is associated with the flux of protons through voltage-activated proton channels. Both proton and electron currents can be recorded with the patch-clamp technique, but whether the oxidase is a proton channel or a proton channel modulator remains controversial. Recently, we have used the inside–out configuration of the patch-clamp technique to record proton and electron currents in excised patches. This approach allows us to measure the oxidase activity under very controlled conditions, and has provided new information about the enzymatic activity of the oxidase and its coupling to proton channels. In this chapter I will discuss how the unique characteristics of the electron and proton currents associated with the redox activity of the NADPH oxidase have extended our knowledge about the thermodynamics and the physiological regulation of this remarkable enzyme. PMID:16321802

  19. Human lysyl oxidase-like 2.

    Science.gov (United States)

    Moon, Hee-Jung; Finney, Joel; Ronnebaum, Trey; Mure, Minae

    2014-12-01

    Lysyl oxidase like-2 (LOXL2) belongs to the lysyl oxidase (LOX) family, which comprises Cu(2+)- and lysine tyrosylquinone (LTQ)-dependent amine oxidases. LOXL2 is proposed to function similarly to LOX in the extracellular matrix (ECM) by promoting crosslinking of collagen and elastin. LOXL2 has also been proposed to regulate extracellular and intracellular cell signaling pathways. Dysregulation of LOXL2 has been linked to many diseases, including cancer, pro-oncogenic angiogenesis, fibrosis and heart diseases. In this review, we will give an overview of the current understandings and hypotheses regarding the molecular functions of LOXL2. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Retroactive Interference and Forgetting

    Directory of Open Access Journals (Sweden)

    Vinishaa Ankala

    2011-01-01

    Full Text Available Retroactive interference is the amount of information that can be forgotten by a person over time due to newly learned material. In this paper we establish a relationship between the amount of information forgotten by college students while they read and watch television and the time taken to forget it. We equate these numerical equations to solve for the unknown constants. By doing so, we can find the exact equation and also the amount of forgetting information due to retroactive interference.

  1. Cholesterol Regulates Syntaxin 6 Trafficking at trans-Golgi Network Endosomal Boundaries

    Directory of Open Access Journals (Sweden)

    Meritxell Reverter

    2014-05-01

    Full Text Available Inhibition of cholesterol export from late endosomes causes cellular cholesterol imbalance, including cholesterol depletion in the trans-Golgi network (TGN. Here, using Chinese hamster ovary (CHO Niemann-Pick type C1 (NPC1 mutant cell lines and human NPC1 mutant fibroblasts, we show that altered cholesterol levels at the TGN/endosome boundaries trigger Syntaxin 6 (Stx6 accumulation into VAMP3, transferrin, and Rab11-positive recycling endosomes (REs. This increases Stx6/VAMP3 interaction and interferes with the recycling of αVβ3 and α5β1 integrins and cell migration, possibly in a Stx6-dependent manner. In NPC1 mutant cells, restoration of cholesterol levels in the TGN, but not inhibition of VAMP3, restores the steady-state localization of Stx6 in the TGN. Furthermore, elevation of RE cholesterol is associated with increased amounts of Stx6 in RE. Hence, the fine-tuning of cholesterol levels at the TGN-RE boundaries together with a subset of cholesterol-sensitive SNARE proteins may play a regulatory role in cell migration and invasion.

  2. Niacin to Boost Your HDL "Good" Cholesterol

    Science.gov (United States)

    Niacin can boost 'good' cholesterol Niacin is a B vitamin that may raise your HDL ("good") cholesterol. But side effects might outweigh benefits for most ... been used to increase high-density lipoprotein (HDL) cholesterol — the "good" cholesterol that helps remove low-density ...

  3. Quantum interference in polyenes.

    Science.gov (United States)

    Tsuji, Yuta; Hoffmann, Roald; Movassagh, Ramis; Datta, Supriyo

    2014-12-14

    The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or by an odd number of carbons at both ends (transmission turned on or annihilated). These prescriptions for the occurrence of quantum interference lead to an unexpected consequence for switches which realize such extension through electrocyclic reactions: for some specific attachment modes the chemically closed ring will be the ON position of the switch. Normally the signs of the entries of the Green's function matrix are assumed to have no physical significance; however, we show that the signs may have observable consequences. In particular, in the case of multiple probe attachments - if coherence in probe connections can be arranged - in some cases new destructive interference results, while in others one may have constructive interference. One such case may already exist in the literature.

  4. Localization of Interference Fringes.

    Science.gov (United States)

    Simon, J. M.; Comastri, Silvia A.

    1980-01-01

    Discusses a proof for determining the localized fringes position arrived at when one considers the interference of two extended sources when one is able to observe fringes only at certain points in space. Shows how the localized fringes may be found in a device used to observe Newton's rings. (Author/CS)

  5. Laser Interference Lithography

    NARCIS (Netherlands)

    van Wolferen, Hendricus A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  6. NADPH oxidase involvement in cellular integrity.

    Science.gov (United States)

    Macpherson, Neil; Takeda, Seiji; Shang, Zhonglin; Dark, Adeeba; Mortimer, Jennifer C; Brownlee, Colin; Dolan, Liam; Davies, Julia M

    2008-05-01

    NADPH oxidase activity is involved in plant adaptation and development. The reactive oxygen species sourced by NADPH oxidase activity may contribute to wall strength and protoplast volume adjustment. Root hair bulge apices of the NADPH oxidase mutant rhd2/Atrbohc were more robust than the kjk cellulose synthase mutant, but burst more readily than the wild type (WT). Root epidermal wall appeared impaired in rhd2/Atrbohc, as revealed by the number of protoplasts released by wall-degrading enzymes. Root hair bulges of rhd2/Atrbohc burst more than the WT when challenged in situ with hypo-osmotic low ionic strength medium. Inhibition of NADPH oxidase activity with diphenylene iodonium caused WT to phenocopy the rhd2/Atrbohc bursting in response to hypo-osmotic shock. This implicates RHD2/AtRBOHC in softening the cell wall to permit protoplast expansion. Overall, the results point to a role for RHD2/AtRBOHC in contributing to wall strength.

  7. Vanillyl-alcohol oxidase, a tasteful biocatalyst

    NARCIS (Netherlands)

    Heuvel, Robert H.H. van den; Fraaije, Marco W.; Mattevi, Andrea; Laane, Colja; Berkel, Willem J.H. van

    2001-01-01

    The covalent flavoenzyme vanillyl-alcohol oxidase (VAO) is a versatile biocatalyst. It converts a wide range of phenolic compounds by catalysing oxidation, deamination, demethylation, dehydrogenation and hydroxylation reactions. The production of natural vanillin, 4-hydroxybenzaldehyde, coniferyl

  8. Glucose concentration determination based on silica sol-gel encapsulated glucose oxidase optical biosensor arrays.

    Science.gov (United States)

    Chang, Gang; Tatsu, Yoshiro; Goto, Tatsushi; Imaishi, Hiromasa; Morigaki, Kenichi

    2010-11-15

    Optical biosensor arrays for rapidly determining the glucose concentrations in a large number of beverage and blood samples were developed by immobilizing glucose oxidase (GOD) on oxygen sensor layer. Glucose oxidase was first encapsulated in silica based gels through sol-gel approach and then immobilized on 96-well microarrays integrated with oxygen sensing film at the bottom. The oxygen sensing film was made of an organically modified silica film (ORMOSIL) doped with tris(4,7-diphenyl-1,10-phenanthroline) ruthenium dichloride (Ru(dpp)(3)Cl(2)). The oxidation reaction of glucose by glucose oxidase could be monitored through fluorescence intensity enhancement due to the oxygen consumption in the reaction. The luminescence changing rate evaluated by the dynamic transient method (DTM) was correlated with the glucose concentration with the wide linear range from 0.1 to 5.0mM (Y=13.28X-0.128, R=0.9968) and low detection limit (0.06 mM). The effects of pH and coexisting ions were systemically studied. The results showed that the optical biosensor arrays worked under a wide range of pH value, and normal interfering species such as Na(+), K(+), Cl(-), PO(4)(3-), and ascorbic acid did not cause apparent interference on the measurement. The activity of glucose oxidase was mostly retained even after 2-month storage, indicating their long-term stability. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Coordination chemistry controls the thiol oxidase activity of the B12-trafficking protein CblC.

    Science.gov (United States)

    Li, Zhu; Shanmuganathan, Aranganathan; Ruetz, Markus; Yamada, Kazuhiro; Lesniak, Nicholas A; Kräutler, Bernhard; Brunold, Thomas C; Koutmos, Markos; Banerjee, Ruma

    2017-06-09

    The cobalamin or B 12 cofactor supports sulfur and one-carbon metabolism and the catabolism of odd-chain fatty acids, branched-chain amino acids, and cholesterol. CblC is a B 12 -processing enzyme involved in an early cytoplasmic step in the cofactor-trafficking pathway. It catalyzes the glutathione (GSH)-dependent dealkylation of alkylcobalamins and the reductive decyanation of cyanocobalamin. CblC from Caenorhabditis elegans ( ce CblC) also exhibits a robust thiol oxidase activity, converting reduced GSH to oxidized GSSG with concomitant scrubbing of ambient dissolved O 2 The mechanism of thiol oxidation catalyzed by ce CblC is not known. In this study, we demonstrate that novel coordination chemistry accessible to ce CblC-bound cobalamin supports its thiol oxidase activity via a glutathionyl-cobalamin intermediate. Deglutathionylation of glutathionyl-cobalamin by a second molecule of GSH yields GSSG. The crystal structure of ce CblC provides insights into how architectural differences at the α- and β-faces of cobalamin promote the thiol oxidase activity of ce CblC but mute it in wild-type human CblC. The R161G and R161Q mutations in human CblC unmask its latent thiol oxidase activity and are correlated with increased cellular oxidative stress disease. In summary, we have uncovered key architectural features in the cobalamin-binding pocket that support unusual cob(II)alamin coordination chemistry and enable the thiol oxidase activity of ce CblC. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Artificial Intelligence versus Statistical Modeling and Optimization of Cholesterol Oxidase Production by using Streptomyces Sp

    National Research Council Canada - National Science Library

    Pathak, Lakshmi; Singh, Vineeta; Niwas, Ram; Osama, Khwaja; Khan, Saif; Haque, Shafiul; Tripathi, C K M; Mishra, B N

    2015-01-01

    ... and statistical techniques and generally used for modeling and analysis of problems associated with multivariable systems. It is based on design of experiments (DOE) for the development of models, estimation of the model coefficients and prediction of the response for optimum conditions [2, 3]. RSM estimates the relationship between the response...

  11. Regulation of biliary cholesterol secretion and reverse cholesterol transport

    NARCIS (Netherlands)

    Dikkers, Arne

    2016-01-01

    According to the World Health Organization the number one cause of death throughout the world is cardiovascular disease. Therefore, there is an urgent need for new therapeutic strategies to prevent and treat cardiovascular disease. One possible way is to target the HDL-driven reverse cholesterol

  12. Binaural interference: effects of temporal interferer fringe and interstimulus interval.

    Science.gov (United States)

    Camalier, Corrie R; Grantham, D Wesley; Bernstein, Leslie R

    2014-02-01

    Binaural interference refers to the phenomenon in which the potency of binaural cues conveyed by a "target" stimulus occupying one spectral region is degraded by the presence of an "interferer" stimulus occupying a spectral region remote from the target. It is typified by conditions in which thresholds for detection of interaural temporal difference conveyed by a high-frequency target are elevated when the target is accompanied by a spectrally remote low-frequency interferer. This study explored effects of temporal relations between targets and interferers on binaural interference. In the first experiment, duration by which the interferer preceded and/or trailed the target (onset and offset "fringes") was varied. Results indicated binaural interference decreased with total duration of the temporal fringe, but did not depend on whether that duration was composed of onset, offset, or onset + offset fringes. In the second experiment, binaural interference was measured as a function of the interstimulus interval (ISI) between the two presentations of the target. Results indicated that shorter ISIs increased thresholds in both the interferer and no-interferer conditions, but did not affect binaural interference. These results suggest that the mechanisms underlying the effects of manipulations of the interferer temporal fringe and manipulation of the ISI are essentially independent.

  13. Remnant cholesterol and ischemic heart disease

    DEFF Research Database (Denmark)

    Varbo, Anette; Nordestgaard, Børge G

    2014-01-01

    PURPOSE OF REVIEW: To review recent advances in the field of remnant cholesterol as a contributor to the development of ischemic heart disease (IHD). RECENT FINDINGS: Epidemiologic, mechanistic, and genetic studies all support a role for elevated remnant cholesterol (=cholesterol in triglyceride......-rich lipoproteins) as a contributor to the development of atherosclerosis and IHD. Observational studies show association between elevated remnant cholesterol and IHD, and mechanistic studies show remnant cholesterol accumulation in the arterial wall like LDL-cholesterol (LDL-C) accumulation. Furthermore, large...... genetic studies show evidence of remnant cholesterol as a causal risk factor for IHD independent of HDL-cholesterol levels. Genetic studies also show that elevated remnant cholesterol is associated with low-grade inflammation, whereas elevated LDL-C is not. There are several pharmacologic ways of lowering...

  14. Interference between Streptococcus pneumoniae and Staphylococcus aureus: In Vitro Hydrogen Peroxide-Mediated Killing by Streptococcus pneumoniae

    OpenAIRE

    Regev-Yochay, Gili; Trzciński, Krzysztof; Thompson, Claudette M.; Malley, Richard; Lipsitch, Marc

    2006-01-01

    The bactericidal activity of Streptococcus pneumoniae toward Staphylococcus aureus is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies.

  15. Interference between Streptococcus pneumoniae and Staphylococcus aureus: In Vitro Hydrogen Peroxide-Mediated Killing by Streptococcus pneumoniae

    Science.gov (United States)

    Regev-Yochay, Gili; Trzciński, Krzysztof; Thompson, Claudette M.; Malley, Richard; Lipsitch, Marc

    2006-01-01

    The bactericidal activity of Streptococcus pneumoniae toward Staphylococcus aureus is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies. PMID:16788209

  16. Interference Rejection and Management

    Science.gov (United States)

    2009-07-01

    there has been some work relating to NBI suppression in coded OFDM systems [12, 45, 57]. In this work, the prediction-error filter ( PEF ) [30, 60] is...error filter ( PEF ) is considered for this system as a means for removing the interference in the time domain, thereby avoiding the spectral leakage that...occurs after demodulation (see block diagram given in Fig. 9.6). The PEF is a well-studied structure that uses the correlation between past samples to

  17. Diboson interference resurrection

    Science.gov (United States)

    Panico, Giuliano; Riva, Francesco; Wulzer, Andrea

    2018-01-01

    High-energy diboson processes at the LHC are potentially powerful indirect probes of heavy new physics, whose effects can be encapsulated in higher-dimensional operators or in modified Standard Model couplings. An obstruction however comes from the fact that leading new physics effects often emerge in diboson helicity amplitudes that are anomalously small in the Standard Model. As such, the formally leading Standard Model/New Physics interference contribution cancels in inclusive measurements. This paper describes a solution to this problem.

  18. Totally Asynchronous Interference Channels

    CERN Document Server

    Moshksar, Kamyar

    2010-01-01

    This paper addresses an interference channel consisting of $\\mathbf{n}$ active users sharing $u$ frequency sub-bands. Users are asynchronous meaning there exists a mutual delay between their transmitted codes. A stationary model for interference is considered by assuming the starting point of an interferer's data is uniformly distributed along the codeword of any user. The spectrum is divided to private and common bands each containing $v_{\\mathrm{p}}$ and $v_{\\mathrm{c}}$ frequency sub-bands respectively. We consider a scenario where all transmitters are unaware of the number of active users and the channel gains. The optimum $v_{\\mathrm{p}}$ and $v_{\\mathrm{c}}$ are obtained such that the so-called outage capacity per user is maximized. If $\\Pr\\{\\mathbf{n}\\leq 2\\}=1$, upper and lower bounds on the mutual information between the input and output of the channel for each user are derived using a genie-aided technique. The proposed bounds meet each other as the code length grows to infinity yielding a closed ex...

  19. Membrane Cholesterol Modulates Superwarfarin Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Marangoni, M. Natalia; Martynowycz, Michael W.; Kuzmenko, Ivan; Braun, David; Polak, Paul E.; Weinberg, Guy; Rubinstein, Israel; Gidalevitz, David; Feinstein, Douglas L.

    2016-04-26

    Superwarfarins are modified analogs of warfarin with additional lipophilic aromatic rings, up to 100-fold greater potency, and longer biological half-lives. We hypothesized that increased hydrophobicity allowed interactions with amphiphilic membranes and modulation of biological responses. We find that superwarfarins brodifacoum and difenacoum increase lactate production and cell death in neuroblastoma cells. In contrast, neither causes changes in glioma cells that have higher cholesterol content. After choleterol depletion, lactate production was increased and cell viability was reduced. Drug-membrane interactions were examined by surface X-ray scattering using Langmuir monolayers of dipalmitoylphosphatidylcholine and/or cholesterol. Specular X-ray reflectivity data revealed that superwarfarins, but not warfarin, intercalate between dipalmitoylphosphatidylcholine molecules, whereas grazing incidence X-ray diffraction demonstrated changes in lateral crystalline order of the film. Neither agent showed significant interactions with monolayers containing >20% cholesterol. These findings demonstrate an affinity of superwarfarins to biomembranes and suggest that cellular responses to these agents are regulated by cholesterol content.

  20. Low temperature synthesis of seed mediated CuO bundle of nanowires, their structural characterisation and cholesterol detection

    Energy Technology Data Exchange (ETDEWEB)

    Ibupoto, Z.H., E-mail: zafar.hussin.ibupoto@liu.se [Department of Science and Technology, Linköping University, Campus Norrköping, SE-60174 Norrköping (Sweden); Khun, K. [Department of Science and Technology, Linköping University, Campus Norrköping, SE-60174 Norrköping (Sweden); Liu, X. [Department of Physics, Chemistry, and Biology (IFM), Linköping University, 58183 Linköping Sweden (Sweden); Willander, M. [Department of Science and Technology, Linköping University, Campus Norrköping, SE-60174 Norrköping (Sweden)

    2013-10-15

    In this study, we have successfully synthesised CuO bundle of nanowires using simple, cheap and low temperature hydrothermal growth method. The growth parameters such as precursor concentration and time for duration of growth were optimised. The field emission scanning electron microscopy (FESEM) has demonstrated that the CuO bundles of nanowires are highly dense, uniform and perpendicularly oriented to the substrate. The high resolution transmission electron microscopy (HRTEM) has demonstrated that the CuO nanostructures consist of bundle of nanowires and their growth pattern is along the [010] direction. The X-ray diffraction (XRD) technique described that CuO bundle of nanowires possess the monoclinic crystal phase. The surface and chemical composition analyses were carried out with X-ray photoelectron spectroscopy (XPS) technique and the obtained results suggested the pure crystal state of CuO nanostructures. In addition, the CuO nanowires were used for the cholesterol sensing application by immobilising the cholesterol oxidase through electrostatic attraction. The infrared reflection absorption spectroscopy study has also revealed that CuO nanostructures are consisting of only Cu-O bonding and has also shown the possible interaction of cholesterol oxidase with the sharp edge surface of CuO bundle of nanowires. The proposed cholesterol sensor has demonstrated the wide range of detection of cholesterol with good sensitivity of 33.88 ± 0.96 mV/decade. Moreover, the CuO bundle of nanowires based sensor electrode has revealed good repeatability, reproducibility, stability, selectivity and a fast response time of less than 10 s. The cholesterol sensor based on the immobilised cholesterol oxidase has good potential applicability for the determination of cholesterol from the human serum and other biological samples. - Highlights: • This study describes the synthesis of bundle of CuO nanowires by hydrothermal method. • CuO nanostructures exhibit good alignment and

  1. Lymphatic vessels are essential for the removal of cholesterol from peripheral tissues by SR-BI-mediated transport of HDL.

    Science.gov (United States)

    Lim, Hwee Ying; Thiam, Chung Hwee; Yeo, Kim Pin; Bisoendial, Radjesh; Hii, Chung Shii; McGrath, Kristine C Y; Tan, Kar Wai; Heather, Alison; Alexander, J Steven Jonathan; Angeli, Veronique

    2013-05-07

    Removal of cholesterol from peripheral tissues to the bloodstream via reverse cholesterol transport (RCT) is a process of major biological importance. Here we demonstrate that lymphatic drainage is required for RCT. We have previously shown that hypercholesterolemia in mice is associated with impaired lymphatic drainage and increased lipid accumulation in peripheral tissues. We now show that restoration of lymphatic drainage in these mice significantly improves cholesterol clearance. Conversely, obstruction of lymphatic vessels in wild-type mice significantly impairs RCT. Finally, we demonstrate using silencing RNA interference, neutralizing antibody, and transgenic mice that removal of cholesterol by lymphatic vessels is dependent on the uptake and transcytosis of HDL by scavenger receptor class B type I expressed on lymphatic endothelium. Collectively, this study challenges the current view that lymphatic endothelium is a passive exchange barrier for cholesterol transport and provides further evidence for its interplay with lipid biology in health and disease. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Healthy Dietary Fats Help Beat High Cholesterol

    Science.gov (United States)

    ... 166625.html Healthy Dietary Fats Help Beat High Cholesterol Eating them can reduce your risk of heart ... ones found in some vegetable oils can reduce cholesterol levels and heart disease risk as much as ...

  3. High Cholesterol: Medicines to Help You

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women High Cholesterol--Medicines To Help You Share Tweet Linkedin Pin ... side effects for each drug, check Drugs@FDA . Cholesterol Absorption Inhibitors Brand Name Generic Name Zetia Ezetimibe ...

  4. New Cholesterol Fighting Meds Target Key Gene

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_165942.html New Cholesterol Fighting Meds Target Key Gene Two trials show ... New gene-based therapies appear to significantly decrease cholesterol levels in people, and could even cut down ...

  5. Do You Know Your Cholesterol Levels?

    Science.gov (United States)

    ... The Health Information Center Do You Know Your Cholesterol Levels? Print-friendly Version (PDF, 6.1 MB) ... Eat Smart Did you know that high blood cholesterol is a serious problem among Latinos? About one ...

  6. Cholesterol: the debate should be terminated.

    Science.gov (United States)

    Nathan, David G

    2017-07-01

    Here, I offer personal perspectives on cholesterol homeostasis that reflect my belief that certain aspects of the debate have been overstated.-Nathan, D. G. Cholesterol: the debate should be terminated. © FASEB.

  7. Diboson interference resurrection

    Directory of Open Access Journals (Sweden)

    Giuliano Panico

    2018-01-01

    Full Text Available High-energy diboson processes at the LHC are potentially powerful indirect probes of heavy new physics, whose effects can be encapsulated in higher-dimensional operators or in modified Standard Model couplings. An obstruction however comes from the fact that leading new physics effects often emerge in diboson helicity amplitudes that are anomalously small in the Standard Model. As such, the formally leading Standard Model/New Physics interference contribution cancels in inclusive measurements. This paper describes a solution to this problem.

  8. RNA interference in Lepidoptera

    DEFF Research Database (Denmark)

    Terenius, Ole; Papanicolaou, Alexie; Garbutt, Jennie S.

    2011-01-01

    Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive...... is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success...

  9. Cholesterol 24-hydroxylase: Brain cholesterol metabolism and beyond.

    Science.gov (United States)

    Moutinho, Miguel; Nunes, Maria João; Rodrigues, Elsa

    2016-12-01

    Dysfunctions in brain cholesterol homeostasis have been extensively related to brain disorders. The major elimination pathway of brain cholesterol is its hydroxylation into 24 (S)-hydroxycholesterol by the cholesterol 24-hydroxylase (CYP46A1). Interestingly, there seems to be an association between CYP46A1 and high-order brain functions, in a sense that increased expression of this hydroxylase improves cognition, while a reduction leads to a poor cognitive performance. Moreover, increasing amount of epidemiological, biochemical and molecular evidence, suggests that CYP46A1 has a role in the pathogenesis or progression of neurodegenerative disorders, in which up-regulation of this enzyme is clearly beneficial. However, the mechanisms underlying these effects are poorly understood, which highlights the importance of studies that further explore the role of CYP46A1 in the central nervous system. In this review we summarize the major findings regarding CYP46A1, and highlight the several recently described pathways modulated by this enzyme from a physiological and pathological perspective, which might account for novel therapeutic strategies for neurodegenerative disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. multicopper oxidases important for human iron metabolism

    Directory of Open Access Journals (Sweden)

    Diana Wierzbicka

    2014-01-01

    Full Text Available Multi-copper oxidases are a group of proteins which demonstrate enzymatic activity and are capable of oxidizing their substrates with the concomitant reduction of dioxygen to two water molecules. For some multi-copper oxidases there has been demonstrated ferroxidase activity which is related to their specific structure characterized by the presence of copper centres and iron-binding sites. Three multi-copper oxidases have been included in this group: ceruloplasmin, hephaestin and zyklopen. Multi copper oxidases which are expressed in different tissues are capable of oxidizing a wide spectrum of substrates. Multi-copper oxidases are capable of oxidizing a wide spectrum of substrates. Ceruloplasmin exhibits antioxidant activity as well as being involved in many other biological processes. The observations of phenotypic effects of absence or low expression of multi-copper ferroxidase-coding genes suggest that the main role of these proteins is taking part in iron metabolism. The main role of ceruloplasmin in iron turnover is oxidizing Fe2+ into Fe3+, a process which is essential for iron binding to transferrin (the main iron-transporting protein, as well as to ferritin (the main iron-storage protein. The function of hephaestin as ferroxidase is essential for iron binding to apotransferrin in the lamina propria of the intestinal mucosa, a process that is important for further transport of iron to the liver by the portal vein. Available data indicate that zyklopen is responsible for the placental iron transport. The presence of three multi-copper oxidases with ferroxidase activity emphasizes the significance of oxidation for iron metabolism. The distribution of multi-copper ferroxidases in many tissues ensures the proper iron turnover in the body as well as preventing toxic effects related to the presence of Fe2+ ions. These ions contribute to generation of free radicals, including the highly reactive hydroxyl radical, through the Fenton and Haber

  11. Nanoscale Membrane Domain Formation Driven by Cholesterol

    DEFF Research Database (Denmark)

    Javanainen, Matti; Martinez-Seara, Hector; Vattulainen, Ilpo

    2017-01-01

    . The complex nanodomain substructure forms when cholesterol positions itself in the domain boundary region. Here cholesterol can also readily flip-flop across the membrane. Most importantly, replacing cholesterol with a sterol characterized by a less asymmetric ring region impairs the emergence of nanodomains...

  12. Intestinal cholesterol secretion : future clinical implications

    NARCIS (Netherlands)

    Jakulj, L.; Besseling, J.; Stroes, E. S. G.; Groen, A. K.

    2013-01-01

    Together with the liver, the intestine serves as a homeostatic organ in cholesterol metabolism. Recent evidence has substantiated the pivotal role of the intestine in reverse cholesterol transport (RCT). RCT is a fundamental antiatherogenic pathway, mediating the removal of cholesterol from tissues

  13. Isolation of Cholesterol from an Egg Yolk

    Science.gov (United States)

    Taber, Douglass F.; Li, Rui; Anson, Cory M.

    2011-01-01

    A simple procedure for the isolation of the cholesterol, by hydrolysis and extraction followed by column chromatography, is described. The cholesterol can be further purified by complexation with oxalic acid. It can also be oxidized and conjugated to cholestenone. The source of the cholesterol is one egg yolk, which contains about 200 mg of…

  14. Public health aspects of serum cholesterol

    NARCIS (Netherlands)

    S. Houterman (Saskia)

    2001-01-01

    textabstractIn the beginning of this century Anitschkow and De Langen started pioneering work concerning the relation between cholesterol and coronary heart disease. Both showed that there was a possible relation between cholesterol in the diet, blood cholesterol levels and atherosclerosis. It took

  15. Cholesterol Level: Can It Be Too Low?

    Science.gov (United States)

    ... D. A high blood cholesterol level increases your risk of coronary artery disease. Lower cholesterol is usually better, but in rare cases having ... in individuals with heart disease or at high risk of heart disease or stroke. If ... about your cholesterol level, consult your doctor. If you're taking ...

  16. Prevention and Treatment of High Cholesterol (Hyperlipidemia)

    Science.gov (United States)

    ... t is the first step in lowering your risk of heart disease. Cooking for Lower Cholesterol A heart-healthy eating plan can help you ... lowers HDL cholesterol. When a person with high cholesterol also smokes, their risk of coronary heart disease increases more than it otherwise would. ...

  17. The intention interference effect.

    Science.gov (United States)

    Cohen, Anna-Lisa; Kantner, Justin; Dixon, Roger A; Lindsay, D Stephen

    2011-01-01

    Intentions have been shown to be more accessible (e.g., more quickly and accurately recalled) compared to other sorts of to-be-remembered information; a result termed an intention superiority effect (Goschke & Kuhl, 1993). In the current study, we demonstrate an intention interference effect (IIE) in which color-naming performance in a Stroop task was slower for words belonging to an intention that participants had to remember to carry out (Do-the-Task condition) versus an intention that did not have to be executed (Ignore-the-Task condition). In previous work (e.g., Cohen et al., 2005), having a prospective intention in mind was confounded with carrying a memory load. In Experiment 1, we added a digit-retention task to control for effects of cognitive load. In Experiment 2, we eliminated the memory confound in a new way, by comparing intention-related and control words within each trial. Results from both Experiments 1 and 2 revealed an IIE suggesting that interference is very specific to the intention, not just to a memory load.

  18. An innovative method for determining lipemia interference in blood specimens.

    Science.gov (United States)

    Rosenthal, Murray A; Katz, Hyman B

    2011-03-18

    Lipemia interference in blood samples is usually determined by adding exogenous substances that cause turbidity or by using ultracentrifugation to clarify the sample. However, there are a number of problems associated with these methods, which make it difficult to ascertain with certainty that lipemia is the cause of interference. We assessed a novel method for evaluating lipemia interference. Lipemic and non-lipemic serum samples, with similar HDL cholesterol concentrations, were mixed in various proportions (5 concentrations) and assayed for HDL and triglycerides. Thus, matched HDL samples with increasing triglycerides concentrations were tested. We then calculated the percent recovery for HDL for each mixture. Six matched sets of samples had HDL recoveries ranging from 95.9% to 101.1% (n=6 sets, 5 concentrations per set, total of 30 concentrations), with HDL concentrations ranging from 0.78 to 2.16 mmol/l. Triglycerides concentrations in these samples ranged from 1.06 to 9.78 mmol/l for the 30 concentrations. We determined that there was no triglycerides interference on the HDL method performed on the Hitachi S40 Clinical Analyzer up to a triglycerides concentration of 9.78 mmol/l. This matching method is simple to perform and proved useful in evaluating interference due to lipemia. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. MLN64 induces mitochondrial dysfunction associated with increased mitochondrial cholesterol content

    Directory of Open Access Journals (Sweden)

    Elisa Balboa

    2017-08-01

    Full Text Available MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria.

  20. MLN64 induces mitochondrial dysfunction associated with increased mitochondrial cholesterol content.

    Science.gov (United States)

    Balboa, Elisa; Castro, Juan; Pinochet, María-José; Cancino, Gonzalo I; Matías, Nuria; Sáez, P J; Martínez, Alexis; Álvarez, Alejandra R; Garcia-Ruiz, Carmen; Fernandez-Checa, José C; Zanlungo, Silvana

    2017-08-01

    MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH) levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Peptide mediators of cholesterol efflux

    Energy Technology Data Exchange (ETDEWEB)

    Bielicki, John K.; Johansson, Jan

    2013-04-09

    The present invention provides a family of non-naturally occurring polypeptides having cholesterol efflux activity that parallels that of full-length apolipoproteins (e.g., Apo AI and Apo E), and having high selectivity for ABAC1 that parallels that of full-length apolipoproteins. The invention also provides compositions comprising such polypeptides, methods of identifying, screening and synthesizing such polypeptides, and methods of treating, preventing or diagnosing diseases and disorders associated with dyslipidemia, hypercholesterolemia and inflammation.

  2. Partial characterization of lysyl oxidase from several human tissues.

    OpenAIRE

    Kuivaniemi, H

    1985-01-01

    Lysyl oxidase activity was assayed in urea extracts of a number of human tissues, proving to be highest in skin. Antibodies to human placental lysyl oxidase completely inhibited the activity of crude lysyl oxidase from all the human tissues studied, with no significant differences in the amounts of antiserum required for 50% inhibition. By contrast, marked differences were found in this value between skin tissue samples from different species. The Mr of lysyl oxidase in crude extracts of huma...

  3. Inhibition of Human Vascular NADPH Oxidase by Apocynin Derived Oligophenols

    OpenAIRE

    Mora-Pale, Mauricio; Weïwer, Michel; Yu, Jingjing; Linhardt, Robert J.; Dordick, Jonathan S.

    2009-01-01

    Enzymatic oxidation of apocynin, which may mimic in vivo metabolism, affords a large number of oligomers (apocynin oxidation products, AOP) that inhibit vascular NADPH oxidase. In vitro studies of NADPH oxidase activity were performed to identify active inhibitors, resulting in a trimer hydroxylated quinone (IIIHyQ) that inhibited NADPH oxidase with an IC50 = 31 nM. Apocynin itself possessed minimal inhibitory activity. NADPH oxidase is believed to be inhibited through prevention of the inter...

  4. Cholesterol Depletion from a Ceramide/Cholesterol Mixed Monolayer: A Brewster Angle Microscope Study

    KAUST Repository

    Mandal, Pritam

    2016-06-01

    Cholesterol is crucial to the mechanical properties of cell membranes that are important to cells’ behavior. Its depletion from the cell membranes could be dramatic. Among cyclodextrins (CDs), methyl beta cyclodextrin (MβCD) is the most efficient to deplete cholesterol (Chol) from biomembranes. Here, we focus on the depletion of cholesterol from a C16 ceramide/cholesterol (C16-Cer/Chol) mixed monolayer using MβCD. While the removal of cholesterol by MβCD depends on the cholesterol concentration in most mixed lipid monolayers, it does not depend very much on the concentration of cholesterol in C16-Cer/Chol monolayers. The surface pressure decay during depletion were described by a stretched exponential that suggested that the cholesterol molecules are unable to diffuse laterally and behave like static traps for the MβCD molecules. Cholesterol depletion causes morphology changes of domains but these disrupted monolayers domains seem to reform even when cholesterol level was low.

  5. Analysis of Cholesterol Trafficking with Fluorescent Probes

    DEFF Research Database (Denmark)

    Maxfield, Frederick R.; Wustner, Daniel

    2012-01-01

    Cholesterol plays an important role in determining the biophysical properties of biological membranes, and its concentration is tightly controlled by homeostatic processes. The intracellular transport of cholesterol among organelles is a key part of the homeostatic mechanism, but sterol transport...... that can bind to cholesterol to reveal its distribution in cells. We also discuss the use of intrinsically fluorescent sterols that closely mimic cholesterol, as well as some minimally modified fluorophore-labeled sterols. Methods for imaging these sterols by conventional fluorescence microscopy...... and by multiphoton microscopy are described. Some label-free methods for imaging cholesterol itself are also discussed briefly....

  6. Biliary cholesterol secretion : More than a simple ABC

    NARCIS (Netherlands)

    Dikkers, Arne; Tietge, Uwe J. F.

    2010-01-01

    Biliary cholesterol secretion is a process important for 2 major disease complexes, atherosclerotic cardiovascular disease and cholesterol gallstone disease With respect to cardiovascular disease, biliary cholesterol secretion is regarded as the final step for the elimination of cholesterol

  7. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis

    NARCIS (Netherlands)

    Kopacz, Malgorzata; Heuts, Dominic P. H. M.; Fraaije, Marco W.

    2014-01-01

    Putrescine oxidase from Rhodococcus erythropolis (PuO) is a flavin-containing amine oxidase from the monoamine oxidase family that performs oxidative deamination of aliphatic diamines. In this study we report pre-steady-state kinetic analyses of the enzyme with the use of single-and double-mixing

  8. THERMOSTABILITY OF RESPIRATORY TERMINAL OXIDASES IN THE LIPID ENVIRONMENT

    NARCIS (Netherlands)

    Elferink, Marieke G.L.; Bosmal, Tjibbe; Lolkema, Juke S.; Gleiszner, Michael; Driessen, Arnold J.M.; Konings, Wil N.

    1995-01-01

    The effect of the lipid environment on the thermostability of three respiratory terminal oxidases was determined. Cytochrome-e oxidase from beef heart and Bacillus stearothermophilus were used as representative proteins from mesophilic and thermophilic origin, respectively. Quinol oxidase from the

  9. Graphene quantum interference photodetector

    Directory of Open Access Journals (Sweden)

    Mahbub Alam

    2015-03-01

    Full Text Available In this work, a graphene quantum interference (QI photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach–Zehnder interferometer (MZI, which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector, low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  10. Graphene quantum interference photodetector.

    Science.gov (United States)

    Alam, Mahbub; Voss, Paul L

    2015-01-01

    In this work, a graphene quantum interference (QI) photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach-Zehnder interferometer (MZI), which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector), low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  11. NADPH oxidases in Microglia oxidant production

    DEFF Research Database (Denmark)

    Haslund-Vinding, J; McBean, G; Jaquet, V

    2017-01-01

    Microglia are the resident immune cells of the central nervous system (CNS) and constitute a self-sustaining population of CNS-adapted tissue macrophages. As mononuclear phagocytic cells, they express high levels of superoxide-producing NADPH oxidases (NOX). The sole function of members of the NOX...

  12. Lysyl oxidase and adipose tissue dysfunction

    DEFF Research Database (Denmark)

    Pastel, Emilie; Price, Emily; Sjöholm, Kajsa

    2018-01-01

    BACKGROUND/OBJECTIVES: Lysyl oxidase (LOX) is an enzyme crucial for collagen fibre crosslinking and thus for fibrosis development. Fibrosis is characterised by a surplus of collagen fibre accumulation and is amongst others also a feature of obesity-associated dysfunctional adipose tissue (AT) which...

  13. Cholesterol

    Science.gov (United States)

    ... Mental Health Sex and Birth Control Sex and Sexuality Birth Control Family HealthInfants and Toddlers Kids and Teens Pregnancy and ... Mental Health Sex and Birth Control Sex and Sexuality Birth Control Family HealthInfants and Toddlers Kids and Teens Pregnancy and ...

  14. Quantum Interference in Graphene Nanoconstrictions.

    Science.gov (United States)

    Gehring, Pascal; Sadeghi, Hatef; Sangtarash, Sara; Lau, Chit Siong; Liu, Junjie; Ardavan, Arzhang; Warner, Jamie H; Lambert, Colin J; Briggs, G Andrew D; Mol, Jan A

    2016-07-13

    We report quantum interference effects in the electrical conductance of chemical vapor deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multimode Fabry-Pérot interferences can be attributed to reflections at potential steps inside the channel. Sharp antiresonance features with a Fano line shape are observed. Theoretical modeling reveals that these Fano resonances are due to localized states inside the constriction, which couple to the delocalized states that also give rise to the Fabry-Pérot interference patterns. This study provides new insight into the interplay between two fundamental forms of quantum interference in graphene nanoconstrictions.

  15. Novel paper-based cholesterol biosensor using graphene/polyvinylpyrrolidone/polyaniline nanocomposite.

    Science.gov (United States)

    Ruecha, Nipapan; Rangkupan, Ratthapol; Rodthongkum, Nadnudda; Chailapakul, Orawon

    2014-02-15

    A novel nanocomposite of graphene (G), polyvinylpyrrolidone (PVP) and polyaniline (PANI) has been successfully prepared and used for the modification of paper-based biosensors via electrospraying. The droplet-like nanostructures of G/PVP/PANI-modified electrodes are obtained with an average size of 160 ± 1.02 nm. Interestingly, the presence of small amount of PVP (2 mg mL(-1)) in the nanocomposites can substantially improve the dispersibility of G and increase the electrochemical conductivity of electrodes, leading to enhanced sensitivity of the biosensor. The well-defined cyclic voltammogram of standard ferri/ferrocyanide is achieved on a G/PVP/PANI-modified electrode with a 3-fold increase in the current signal compared to an unmodified electrode. This modified electrode also exhibits excellent electrocatalytic activity towards the oxidation of hydrogen peroxide (H2O2). Furthermore, cholesterol oxidase (ChOx) is attached to G/PVP/PANI-modified electrode for the amperometric determination of cholesterol. Under optimum conditions, a linear range of 50 μM to 10mM is achieved and the limit of detection is found to be 1 μM for cholesterol. Finally, the proposed system can be applied for the determination of cholesterol in a complex biological fluid (i.e. human serum). © 2013 Elsevier B.V. All rights reserved.

  16. EFFECT OF CROSSLINKING ON MITOCHONDRIAL CYTOCHROME c OXIDASE

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, Maurice; Packer, Lester

    1979-12-01

    Purified and reconstituted cytochrome {und c} oxidase and mitochondria were crosslinked with biimidates in the presence and absence of cytochrome {und c}. These experiments indicate that oxidase subunit interactions are required for activity and that cytochrome {und c} mobility may be required for electron transport activity. Biimidate treatment of purified and reconstituted oxidase crosslinks all of the oxidase protomers except subunit I when {ge} 20% of the free amines are modified and inhibits steady state oxidase activity. Transient kinetics of ferrocytochrome {und c} oxidation and ferricytochrome {und a} reduction indicates inhibition of electron transfer from heme {und a} to heme {und a}{sub 3}. Crosslinking oxidase molecules to form large aggregates displaying rotational correlation times {ge} 1 ms does not affect oxidase activity. Crosslinking of mitochondria covalently binds the bc{sub 1} and {und aa}{sub 3} complexes to cytochrome {und c}, and inhibits steady-state oxidase activity considerably more than in the case of the purified oxidase. Addition of cytochrome {und c} to the purified oxidase or to {und c}-depleted mitoplasts increases inhibition slightly. Cytochrome {und c} oligomers act as competitive inhibitors of native {und c}, however, crosslinking of cytochrome {und c} to {und c}-depleted mitoplasts or purified oxidase (with dimethyl suberimidate or hetrobifunctional crosslinking reagents) results in a catalytically inactive complex.

  17. A role for NADPH oxidase in antigen presentation

    Directory of Open Access Journals (Sweden)

    Gail J Gardiner

    2013-09-01

    Full Text Available The nicotinamide adenine dinucleotide phosphate (NADPH oxidase expressed in phagocytes is a multi-subunit enzyme complex that generates superoxide (O2.-. This radical is an important precursor of hydrogen peroxide (H2O2 and other reactive oxygen species (ROS needed for microbicidal activity during innate immune responses. Inherited defects in NADPH oxidase give rise to chronic granulomatous disease (CGD, a primary immunodeficiency characterized by recurrent infections and granulomatous inflammation. Interestingly, CGD, CGD carrier status, and oxidase gene polymorphisms have all been associated with autoinflammatory and autoimmune disorders, suggesting a potential role for NADPH oxidase in regulating adaptive immune responses. Here, NADPH oxidase function in antigen processing and presentation is reviewed. NADPH oxidase influences dendritic cell (DC crosspresentation by major histocompatibility complex class I molecules (MHC-I through regulation of the phagosomal microenvironment, while in B lymphocytes, NADPH oxidase alters epitope selection by major histocompatibility complex class II molecules (MHC-II.

  18. Industrial interference and radio astronomy

    Science.gov (United States)

    Jessner, A.

    2013-07-01

    The interferer - victim scenario is described for the case of industrial interference affecting radio astronomical observatories. The sensitivity of radio astronomical receivers and their interference limits are outlined. EMC above 30 MHz is a serious problem for Radio Astronomy. Interferer (CISPR) and victim (ITU-R RA 769) standards are not harmonised. The emissions from the interferer and their spectral characteristics are not defined sufficiently well by CISPR standards. The required minimum coupling losses (MCL) between an industrial device and radio astronomical antenna depends on device properties but is shown to exceed 140 dB in most cases. Spatial separation of a few km is insufficient on its own, the terrain must shield > 30-40 dB, additional mitigations such as extra shielding or suppression of high frequency emissions may be necessary. A case by case compatibility analysis and tailored EMC measures are required for individual installations. Aggregation of many weak rfi emitters can become serious problem. If deployment densities are high enough, the emission constraints can even exceed those for a single interferer at a short distance from the radio observatory. Compatibility studies must account not only for the single interferer but also for many widely distributed interference sources.

  19. Output Interference in Recognition Memory

    Science.gov (United States)

    Criss, Amy H.; Malmberg, Kenneth J.; Shiffrin, Richard M.

    2011-01-01

    Dennis and Humphreys (2001) proposed that interference in recognition memory arises solely from the prior contexts of the test word: Interference does not arise from memory traces of other words (from events prior to the study list or on the study list, and regardless of similarity to the test item). We evaluate this model using output…

  20. The RNA interference revolution

    Directory of Open Access Journals (Sweden)

    G. Lenz

    2005-12-01

    Full Text Available The discovery of double-stranded RNA-mediated gene silencing has rapidly led to its use as a method of choice for blocking a gene, and has turned it into one of the most discussed topics in cell biology. Although still in its infancy, the field of RNA interference has already produced a vast array of results, mainly in Caenorhabditis elegans, but recently also in mammalian systems. Micro-RNAs are short hairpins of RNA capable of blocking translation, which are transcribed from genomic DNA and are implicated in several aspects from development to cell signaling. The present review discusses the main methods used for gene silencing in cell culture and animal models, including the selection of target sequences, delivery methods and strategies for a successful silencing. Expected developments are briefly discussed, ranging from reverse genetics to therapeutics. Thus, the development of the new paradigm of RNA-mediated gene silencing has produced two important advances: knowledge of a basic cellular mechanism present in the majority of eukaryotic cells and access to a potent and specific new method for gene silencing.

  1. Characterizing Destructive Quantum Interference in Electron Transport

    OpenAIRE

    Sam-ang, Panu; Reuter, Matthew G.

    2017-01-01

    Destructive quantum interference in electron transport through molecules provides an unconventional route for suppressing electric current. In this work we introduce "interference vectors" for each interference and use them to characterize the interference. An interference vector may be an orbital of the bare molecule, in which case the interference is very sensitive to perturbation. In contrast, an interference vector may be a combination of multiple molecular orbitals, leading to more robus...

  2. Communications in interference limited networks

    CERN Document Server

    2016-01-01

    This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

  3. Oxidase Activity of the Barnacle Adhesive Interface Involves Peroxide-Dependent Catechol Oxidase and Lysyl Oxidase Enzymes.

    Science.gov (United States)

    So, Christopher R; Scancella, Jenifer M; Fears, Kenan P; Essock-Burns, Tara; Haynes, Sarah E; Leary, Dagmar H; Diana, Zoie; Wang, Chenyue; North, Stella; Oh, Christina S; Wang, Zheng; Orihuela, Beatriz; Rittschof, Dan; Spillmann, Christopher M; Wahl, Kathryn J

    2017-04-05

    Oxidases are found to play a growing role in providing functional chemistry to marine adhesives for the permanent attachment of macrofouling organisms. Here, we demonstrate active peroxidase and lysyl oxidase enzymes in the adhesive layer of adult Amphibalanus amphitrite barnacles through live staining, proteomic analysis, and competitive enzyme assays on isolated cement. A novel full-length peroxinectin (AaPxt-1) secreted by barnacles is largely responsible for oxidizing phenolic chemistries; AaPxt-1 is driven by native hydrogen peroxide in the adhesive and oxidizes phenolic substrates typically preferred by phenoloxidases (POX) such as laccase and tyrosinase. A major cement protein component AaCP43 is found to contain ketone/aldehyde modifications via 2,4-dinitrophenylhydrazine (DNPH) derivatization, also called Brady's reagent, of cement proteins and immunoblotting with an anti-DNPH antibody. Our work outlines the landscape of molt-related oxidative pathways exposed to barnacle cement proteins, where ketone- and aldehyde-forming oxidases use peroxide intermediates to modify major cement components such as AaCP43.

  4. A dual enzymatic-biosensor for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages of diabetic mice: evaluation of the diabetes-accelerated atherosclerosis risk.

    Science.gov (United States)

    Huang, Qilin; An, Yarui; Tang, Linlin; Jiang, Xiaoli; Chen, Hua; Bi, Wenji; Wang, Zhongchuan; Zhang, Wen

    2011-11-30

    In this paper, a novel dual enzymatic-biosensor is described for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages (PMs) of diabetic mice to evaluate the risk of diabetes-accelerated atherosclerosis. The biosensor was constructed by a three-step method. First, a poly-thionine (PTH) film was assembled on the surface of glassy carbon electrode by cyclic voltammetric electropolymerization of thionine, which serves as an electron transfer mediator (ETM). Second, gold nanoparticles (GNPs) were covered on the surface of PTH facilitating the electron transfer between glucose oxidase (GOx), cholesterol oxidase (ChOx) and electrode. Finally, the enzymes, GOx, cholesterol esterase (ChE), and ChOx, were covalently attached to the PTH layer through a chitosan (CH) linker. The PTH coupled with GNPs provides good selectivity, high sensitivity and little crosstalk for the dual enzymatic-biosensor. The developed biosensor had good electrocatalytic activity toward the oxidations of glucose and cholesterol, exhibiting a linear range from 0.008 mM to 6.0 mM for glucose with a detection limit of 2.0 μM, and a linear range from 0.002 mM to 1.0 mM for cholesterol with a detection limit of 0.6 μM. The results of the diabetic mice demonstrated that the cholesterol level did not change obviously with the increase of glucose level in serum, while the cholesterol level was induced with the increase of the glucose level in PMs. Previous studies have shown that the large accumulation of cholesterol in macrophage could lead to macrophage foam cell formation, which is the hallmark of early atherosclerosis. This study provides useful further evidences for the development of diabetes-accelerated atherosclerosis. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Raising HDL cholesterol in women

    Directory of Open Access Journals (Sweden)

    Danny J Eapen

    2009-11-01

    Full Text Available Danny J Eapen1, Girish L Kalra1, Luay Rifai1, Christina A Eapen2, Nadya Merchant1, Bobby V Khan11Emory University School of Medicine, Atlanta, GA, USA; 2University of South Florida School of Medicine, Tampa, FL, USAAbstract: High-density lipoprotein cholesterol (HDL-C concentration is essential in the determination of coronary heart disease (CHD risk in women. This is especially true in the postmenopausal state, where lipid profiles and CHD risk mimic that of age-matched men. Thus, interventions designed to reduce CHD risk by raising HDL-C levels may have particular significance during the transition to menopause. This review discusses HDL-C-raising therapies and the role of HDL in the primary prevention of CHD in women. Lifestyle-based interventions such as dietary change, aerobic exercise regimens, and smoking cessation are initial steps that are effective in raising HDL-C, and available data suggest women respond similarly to men with these interventions. When combined with pharmacotherapy, the effects of these lifestyle alterations are further amplified. Though studies demonstrating gender-specific differences in therapy are limited, niacin continues to be the most effective agent in raising HDL-C levels, especially when used in combination with fibrate or statin therapy. Emerging treatments such as HDL mimetic therapy show much promise in further raising HDL-C levels and improving cardiovascular outcomes.Keywords: high-density lipoprotein, HDL, women, cholesterol, heart disease

  6. A sensitive assay for ABCA1-mediated cholesterol efflux using BODIPY-cholesterol

    Science.gov (United States)

    Sankaranarayanan, Sandhya; Kellner-Weibel, Ginny; de la Llera-Moya, Margarita; Phillips, Michael C.; Asztalos, Bela F.; Bittman, Robert; Rothblat, George H.

    2011-01-01

    Studies have shown a negative association between cellular cholesterol efflux and coronary artery disease (CAD). Standard protocol for quantitating cholesterol efflux involves labeling cells with [3H]cholesterol and measuring release of the labeled sterol. Using [3H]cholesterol is not ideal for the development of a high-throughput assay to screen large numbers of serum as would be required in studying the link between efflux and CAD. We compared efflux using a fluorescent sterol (boron dipyrromethene difluoride linked to sterol carbon-24, BODIPY-cholesterol) with that of [3H]cholesterol in J774 macrophages. Fractional efflux of BODIPY-cholesterol was significantly higher than that of [3H]cholesterol when apo A-I, HDL3, or 2% apoB-depleted human serum were used as acceptors. BODIPY-cholesterol efflux correlated significantly with [3H]cholesterol efflux (p cholesterol efflux correlated significantly with preβ-1 (r2 = 0.6) but not with total HDL-cholesterol. Reproducibility of the BODIPY-cholesterol efflux assay was excellent between weeks (r2 = 0.98, inter-assay CV = 3.31%). These studies demonstrate that BODIPY-cholesterol provides an efficient measurement of efflux compared with [3H]cholesterol and is a sensitive probe for ABCA1-mediated efflux. The increased sensitivity of BODIPY-cholesterol assay coupled with the simplicity of measuring fluorescence results in a sensitive, high-throughput assay that can screen large numbers of sera, and thus establish the relationship between cholesterol efflux and atherosclerosis. PMID:21957199

  7. NPC2 regulates biliary cholesterol secretion via stimulation of ABCG5/G8-mediated cholesterol transport.

    Science.gov (United States)

    Yamanashi, Yoshihide; Takada, Tappei; Yoshikado, Takashi; Shoda, Jun-Ichi; Suzuki, Hiroshi

    2011-05-01

    Biliary cholesterol secretion helps maintain cholesterol homeostasis; it is regulated by the cholesterol exporter adenosine triphosphate-binding cassettes G5 and G8 (ABCG5/G8) and the cholesterol importer Niemann-Pick C1-like 1 (NPC1L1). We studied another putative regulator of cholesterol secretion into bile, Niemann-Pick C2 (NPC2)--a cholesterol-binding protein secreted by the biliary system--and determined its effects on transporter-mediated biliary secretion of cholesterol. Mice with hepatic knockdown of Npc2 or that overexpressed NPC2 were created using adenovirus-mediated gene transfer; biliary lipids were characterized. The effects of secreted NPC2 on cholesterol transporter activity were examined in vitro using cells that overexpressed ABCG5/G8 or NPC1L1. Studies of mice with altered hepatic expression of NPC2 revealed that this expression positively regulates the biliary secretion of cholesterol, supported by the correlation between levels of NPC2 protein and cholesterol in human bile. In vitro analysis showed that secreted NPC2 stimulated ABCG5/G8-mediated cholesterol efflux but not NPC1L1-mediated cholesterol uptake. Consistent with these observations, no significant changes in biliary cholesterol secretion were observed on hepatic overexpression of NPC2 in ABCG5/G8-null mice, indicating that NPC2 requires ABCG5/G8 to stimulate cholesterol secretion. Analyses of NPC2 mutants showed that the stimulatory effect of biliary NPC2 was independent of the function of lysosomal NPC2 as a regulator of intracellular cholesterol trafficking. NPC2 is a positive regulator of biliary cholesterol secretion via stimulation of ABCG5/G8-mediated cholesterol transport. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

  8. Lysyl Oxidase and the Tumor Microenvironment

    Directory of Open Access Journals (Sweden)

    Tong-Hong Wang

    2016-12-01

    Full Text Available The lysyl oxidase (LOX family of oxidases contains a group of extracellular copper-dependent enzymes that catalyze the cross-linking of collagen and elastin by oxidation, thus maintaining the rigidity and structural stability of the extracellular matrix (ECM. Aberrant expression or activation of LOX alters the cellular microenvironment, leading to many diseases, including atherosclerosis, tissue fibrosis, and cancer. Recently, a number of studies have shown that LOX is overexpressed in most cancers and that it is involved in the regulation of tumor progression and metastasis. In contrast, a few reports have also indicated the tumor-suppressing role of LOX. In this short review, we discuss recent research on the correlations between LOX and cancer. Further, the role of LOX in tumor microenvironment remodeling, tumorigenesis, and metastasis and the underlying mechanisms have also been elucidated.

  9. Lysyl Oxidase and the Tumor Microenvironment.

    Science.gov (United States)

    Wang, Tong-Hong; Hsia, Shih-Min; Shieh, Tzong-Ming

    2016-12-29

    The lysyl oxidase (LOX) family of oxidases contains a group of extracellular copper-dependent enzymes that catalyze the cross-linking of collagen and elastin by oxidation, thus maintaining the rigidity and structural stability of the extracellular matrix (ECM). Aberrant expression or activation of LOX alters the cellular microenvironment, leading to many diseases, including atherosclerosis, tissue fibrosis, and cancer. Recently, a number of studies have shown that LOX is overexpressed in most cancers and that it is involved in the regulation of tumor progression and metastasis. In contrast, a few reports have also indicated the tumor-suppressing role of LOX. In this short review, we discuss recent research on the correlations between LOX and cancer. Further, the role of LOX in tumor microenvironment remodeling, tumorigenesis, and metastasis and the underlying mechanisms have also been elucidated.

  10. Lysyl oxidase isoforms in gastric cancer.

    Science.gov (United States)

    Añazco, Carolina; Delgado-López, Fernando; Araya, Paulina; González, Ileana; Morales, Erik; Pérez-Castro, Ramón; Romero, Jacqueline; Rojas, Armando

    2016-09-01

    Gastric cancer (GC) is the fifth most frequent cancer in the world and shows the highest incidence in Latin America and Asia. An increasing amount of evidence demonstrates that lysyl oxidase isoforms, a group of extracellular matrix crosslinking enzymes, should be considered as potential biomarkers and therapeutic targets in GC. In this review, we focus on the expression levels of lysyl oxidase isoforms, its functions and the clinical implications in GC. Finding novel proteins related to the processing of these extracellular matrix enzymes might be helpful in the design of new therapies, which, in combination with classic pharmacology, could be used to delay the progress of this aggressive cancer and offer a wider temporal window for clinical intervention.

  11. NADPH oxidases in the arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Belmondo, Simone; Calcagno, Cristina; Genre, Andrea; Puppo, Alain; Pauly, Nicolas; Lanfranco, Luisa

    2016-01-01

    Plant NADPH oxidases are the major source of reactive oxygen species (ROS) that plays key roles as both signal and stressor in several plant processes, including defense responses against pathogens. ROS accumulation in root cells during arbuscular mycorrhiza (AM) development has raised the interest in understanding how ROS-mediated defense programs are modulated during the establishment of this mutualistic interaction. We have recently analyzed the expression pattern of 5 NADPH oxidase (also called RBOH) encoding genes in Medicago truncatula, showing that only one of them (MtRbohE) is specifically upregulated in arbuscule-containing cells. In line with this result, RNAi silencing of MtRbohE generated a strong alteration in root colonization, with a significant reduction in the number of arbusculated cells. On this basis, we propose that MtRBOHE-mediated ROS production plays a crucial role in the intracellular accommodation of arbuscules.

  12. Cholesterol and late-life cognitive decline.

    Science.gov (United States)

    van Vliet, Peter

    2012-01-01

    High cholesterol levels are a major risk factor for cardiovascular disease, but their role in dementia and cognitive decline is less clear. This review highlights current knowledge on the role of cholesterol in late-life cognitive function, cognitive decline, and dementia. When measured in midlife, high cholesterol levels associate with an increased risk of late-life dementia and cognitive decline. However, when measured in late-life, high cholesterol levels show no association with cognitive function, or even show an inverse relation. Although statin treatment has been shown to associate with a lower risk of dementia and cognitive decline in observational studies, randomized controlled trials show no beneficial effect of statin treatment on late-life cognitive function. Lowering cholesterol levels may impair brain function, since cholesterol is essential for synapse formation and maturation and plays an important role in the regulation of signal transduction through its function as a component of the cell membrane. However, membrane cholesterol also plays a role in the formation and aggregation of amyloid-β. Factors that influence cholesterol metabolism, such as dietary intake, are shown to play a role in late-life cognitive function and the risk of dementia. In conclusion, cholesterol associates with late-life cognitive function, but the association is strongly age-dependent. There is no evidence that treatment with statins in late-life has a beneficial effect on cognitive function.

  13. Process characterization of a monoamine oxidase

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Woodley, John

    2014-01-01

    Redox biocatalysis is currently gaining focus because it offers exquisite selectivity using mild oxidants, such as oxygen (which is environmentally benign). However, it is often challenging to implement oxidative reactions at scale due to the low activity and stability of the biocatalyst under in...... biocatalytic process using a monoamine oxidase to synthesise an intermediate in the manufacture of a drug for treating Hepatitis C (Telaprevir)....

  14. Ligand interactions with galactose oxidase: mechanistic insights.

    Science.gov (United States)

    Whittaker, M M; Whittaker, J W

    1993-01-01

    Interactions between galactose oxidase and small molecules have been explored using a combination of optical absorption, circular dichroism, and electron paramagnetic resonance (EPR) spectroscopies to detect complex formation and characterize the products. Anions bind directly to the cupric center in both active and inactive galactose oxidase, converting to complexes with optical and EPR spectra that are distinctly different from those of the starting aquo enzyme. Azide binding is coupled to stoichiometric proton uptake by the enzyme, reflecting the generation of a strong base (pKa > 9) in the active site anion adduct. At low temperature, the aquo enzyme converts to a form that exhibits the characteristic optical and EPR spectra of an anion complex, apparently reflecting deprotonation of the coordinated water. Anion binding results in a loss of the optical transition arising from coordinated tyrosine, implying displacement of the axial tyrosine ligand on forming the adduct. Nitric oxide binds to galactose oxidase, forming a specific complex exhibiting an unusual EPR spectrum with all g values below 2. The absence of Cu splitting in this spectrum and the observation that the cupric EPR signal from the active site metal ion is not significantly decreased in the complex suggest a nonmetal interaction site for NO in galactose oxidase. These results have been interpreted in terms of a mechanistic scheme where substrate binding displaces a tyrosinate ligand from the active site cupric ion, generating a base that may serve to deprotonate the coordinated hydroxyl group of the substrate, activating it for oxidation. The protein-NO interactions may probe a nonmetal O2 binding site in this enzyme. PMID:8386015

  15. Imaging Monoamine Oxidase in the Human Brain

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J. S.; Volkow, N. D.; Wang, G-J.; Logan, Jean

    1999-11-10

    Positron emission tomography (PET) studies mapping monoamine oxidase in the human brain have been used to measure the turnover rate for MAO B; to determine the minimum effective dose of a new MAO inhibitor drug lazabemide and to document MAO inhibition by cigarette smoke. These studies illustrate the power of PET and radiotracer chemistry to measure normal biochemical processes and to provide information on the effect of drug exposure on specific molecular targets.

  16. Forage polyphenol oxidase and ruminant livestock nutrition

    OpenAIRE

    Michael Richard F. Lee

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to r...

  17. Lysyl oxidase in cancer inhibition and metastasis.

    Science.gov (United States)

    Johnston, Kathryn A; Lopez, Karlo M

    2018-01-05

    Lysyl oxidase is an extracellular matrix, copper - dependent amine oxidase that catalyzes a key enzymatic step in the crosslinking of collagen and elastin. The enzyme is synthesized as a propeptide that is cleaved by procollagen - C - proteinase into two distinct parts: the mature form and the LOX propeptide. The mature enzyme plays a key role in modifying the extracellular matrix and as a result has been implicated in playing a role in the formation of cancer "niches" where tumors will develop and eventually metastasize. On the other hand, the LOX propeptide has been shown to have an inhibitory effect in the development of cancer tumors. New approaches are being developed to test the use of small molecule inhibitors on LOX; however, the lack of a crystal structure has hampered these efforts as it is extremely difficult to design selective inhibitors without knowing what the target receptor looks like. In this mini review we discuss the lysyl oxidase enzyme and its role several types of cancers. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. High Density Lipoproteins and Arteriosclerosis: Role of Cholesterol Efflux and Reverse Cholesterol Transport

    National Research Council Canada - National Science Library

    von Eckardstein, Arnold; Nofer, Jerzy Roch; Assmann, Gerd

    2001-01-01

    Abstract—High density lipoprotein (HDL) cholesterol is an important risk factor for coronary heart disease, and HDL exerts various potentially antiatherogenic properties, including the mediation of reverse transport of cholesterol...

  19. Factors associated with serum cholesterol level in a pediatric practice. Cholesterol screening in a pediatric practice.

    Science.gov (United States)

    Donker, G A; Goff, D C; Ragan, J D; Killinger, R P; Harrist, R B; Labarthe, D R

    1993-01-01

    The associations between age, sex, height, Quetelet index, blood pressure, and serum cholesterol level were examined among 1406 routinely screened children, aged 4 to 19 years, in a pediatric practice. After adjustment for sex and age, height and Quetelet index were associated with serum cholesterol levels. Quetelet index was shown by multiple linear regression to be positively related to cholesterol levels (b = 0.780, P Quetelet index was marginal. Clustering of elevated serum cholesterol level, Quetelet index, and systolic blood pressure was observed. Familial aggregation of cholesterol levels was demonstrated using analysis of variance for 742 children from 342 families included in the regression analysis (F341,400 = 1.56, P Quetelet index, and familial aggregation accounted for 10.6% of the variance in serum cholesterol levels. Siblings of children with high cholesterol levels are a high-yield group in cholesterol screening.

  20. Black pepper and piperine reduce cholesterol uptake and enhance translocation of cholesterol transporter proteins.

    Science.gov (United States)

    Duangjai, Acharaporn; Ingkaninan, Kornkanok; Praputbut, Sakonwun; Limpeanchob, Nanteetip

    2013-04-01

    Black pepper (Piper nigrum L.) lowers blood lipids in vivo and inhibits cholesterol uptake in vitro, and piperine may mediate these effects. To test this, the present study aimed to compare actions of black pepper extract and piperine on (1) cholesterol uptake and efflux in Caco-2 cells, (2) the membrane/cytosol distribution of cholesterol transport proteins in these cells, and (3) the physicochemical properties of cholesterol micelles. Piperine or black pepper extract (containing the same amount of piperine) dose-dependently reduced cholesterol uptake into Caco-2 cells in a similar manner. Both preparations reduced the membrane levels of NPC1L1 and SR-BI proteins but not their overall cellular expression. Micellar cholesterol solubility of lipid micelles was unaffected except by 1 mg/mL concentration of black pepper extract. These data suggest that piperine is the active compound in black pepper and reduces cholesterol uptake by internalizing the cholesterol transporter proteins.

  1. Modulation of lysyl oxidase by dietary copper in rats.

    Science.gov (United States)

    Rucker, R B; Romero-Chapman, N; Wong, T; Lee, J; Steinberg, F M; McGee, C; Clegg, M S; Reiser, K; Kosonen, T; Uriu-Hare, J Y; Murphy, J; Keen, C L

    1996-01-01

    Lysyl oxidase levels were estimated in rat tissues using an enzyme-linked immunosorption assay (ELISA) and a functional assay standardized against known amounts of purified lysyl oxidase. High concentrations of lysyl oxidase (> or = 150 micrograms/g of tissue or packed cells) were detected in connective tissues, such as tendon and skin. Values for aorta, kidney, lung and liver ranged from 30 to 150 micrograms/g of tissue; values for skeletal muscle and diaphragm were tendon (r2 > 0.9). When egg white-based experimental diets containing 2 or 10 micrograms/g added copper were fed to weanling rats, values for skin lysyl oxidase functional activity in the group fed 2 micrograms/g added copper were one-third to one-half the values for skin lysyl oxidase functional activity in rats fed 10 micrograms/g copper. This reduction in lysyl oxidase activity, however, had minimal effect on indices of collagen maturation in rat skin, e.g., collagen solubility in neutral salt and dilute acid or the levels of acid stable cross-links. Moreover, copper deficiency did not influence the steady-state levels of lysyl oxidase specific mRNA in rat skin or the apparent amounts of lysyl oxidase in rat skin as determined by ELISA. These observations underscore that the concentration of lysyl oxidase is relatively high in dense corrective tissues, and although decreasing dietary copper influences functional activity, there is little apparent effect on the production of lysyl oxidase protein.

  2. Lysyl oxidase expression and inhibition in uveal melanoma.

    Science.gov (United States)

    Abourbih, Daniel A; Di Cesare, Sebastian; Orellana, Maria E; Antecka, Emilia; Martins, Claudia; Petruccelli, Luca A; Burnier, Miguel N

    2010-04-01

    Lysyl oxidase is a marker of poor prognosis in several malignancies and is hypothesized to promote a migratory phenotype in hypoxic breast carcinomas. This study aims to characterize the expression of the lysyl oxidase and lysyl oxidase-like proteins in human uveal melanoma cell lines and archival choroidal melanomas using immunohistochemistry. The transcriptional control of lysyl oxidase will also be investigated under simulated hypoxic conditions using cobalt chloride. Lastly, changes in cellular proliferation and invasion will be assessed after the treatment of cell lines with beta-aminopropionitrile, a lysyl oxidase catalytic inhibitor. Retrospective analysis of lysyl oxidase expression in primary human uveal melanoma showed 82% (27 of 33) of tumors being stained positive. High lysyl oxidase expression correlated with the aggressive epithelioid cell type and was associated with shorter metastasis-free survival. Simulated hypoxia resulted in a significant increase in lysyl oxidase mRNA expression. Inhibiting lysyl oxidase's catalytic activity significantly reduced cellular invasion but had no effect on cell proliferation. Our study is the first to show lysyl oxidase expression in primary choroidal melanomas. This protein may represent a potential therapeutic target that warrants further study in this malignancy.

  3. Interference in motor learning - is motor interference sensory?

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye; Petersen, Tue Hvass; Rothwell, John C

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards, but not all motor activities cause interference. After all it is not necessary to remain completely still after practicing a task for learning to occur. Here we ask which...... mechanisms determine whether or not interference occurs. We hypothesised that interference requires the same neural circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects learned a ballistic ankle plantarflexion task. Early motor memory...... learning of the primary task, no interference was observed. Previous studies have suggested that primary motor cortex (M1) may be involved in early motor memory consolidation. 1Hz Repetitive Transcranial Magnetic Stimulation (rTMS) of corticospinal motor output at intensities below ankle movement threshold...

  4. Oxidised LDL, HDL cholesterol, LDL cholesterol levels in patients of coronary artery disease

    OpenAIRE

    Ghosh, Joya; Mishra, T. K.; Rao, Y. N.; Aggarwal, S K

    2006-01-01

    Coronary artery disease is a major cause of morbidity and has various risk factors. Lipid profile i.e. low HDL-cholesterol, high LDL cholesterol, high total cholesterol, high triglycerides playing important role in its causation. Recently interest has been shown in the oxidized fraction of LDL as one of the risk factors. In the present study 60 age and sex matched normal healthy individuals were taken as controls and 60 patients of CAD were taken. Cholesterol was measured by enzymatic method,...

  5. The quantum interference effect transistor.

    Science.gov (United States)

    Stafford, Charles A; Cardamone, David M; Mazumdar, Sumit

    2007-10-24

    We give a detailed discussion of the quantum interference effect transistor (QuIET), a proposed device which exploits the interference between electron paths through aromatic molecules to modulate the current flow. In the off state, perfect destructive interference stemming from the molecular symmetry blocks the current, while in the on state, the current is allowed to flow by locally introducing either decoherence or elastic scattering. Details of a model calculation demonstrating the efficacy of the QuIET are presented, and various fabrication scenarios are proposed, including the possibility of using conducting polymers to connect the QuIET with multiple leads.

  6. Cholesterol Transport Revisited: A New Turbo Mechanism to Drive Cholesterol Excretion

    NARCIS (Netherlands)

    de Boer, Jan Freark; Kuipers, Folkert; Groen, Albert K.

    2017-01-01

    A fine-tuned balance between cholesterol uptake and excretion by the body is pivotal to maintain health and to remain free from the deleterious consequences of cholesterol accumulation such as cardiovascular disease. The pathways involved in intracellular and extracellular cholesterol transport are

  7. Cholesterol Transport Revisited: A New Turbo Mechanism to Drive Cholesterol Excretion

    NARCIS (Netherlands)

    de Boer, Jan Freark; Kuipers, Folkert; Groen, Albert K.

    2018-01-01

    A fine-tuned balance between cholesterol uptake and excretion by the body is pivotal to maintain health and to remain free from the deleterious consequences of cholesterol accumulation such as cardiovascular disease. The pathways involved in intracellular and extracellular cholesterol transport are

  8. Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice

    NARCIS (Netherlands)

    Schonewille, Marleen; de Boer, Jan Freark; Mele, Laura; Wolters, Henk; Bloks, Vincent W.; Wolters, Justina C.; Kuivenhoven, Jan A.; Tietge, Uwe J. F.; Brufau, Gemma; Groen, Albert K.

    Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we

  9. Dietary cholesterol and fats at a young age : do they influence cholesterol metabolism in adult life?

    NARCIS (Netherlands)

    Temmerman, A.M.; Vonk, R.J.; Niezen-Koning, K.; Berger, R.; Fernandes, J.

    1989-01-01

    The effects of dietary cholesterol and fats on cholesterol metabolism later in life were studied in Mongolian gerbils. Three groups were given a basic diet with soybean oil, palm kernel oil amounting to 8.75% (w/w), or the basic diet only. In three other groups, cholesterol (0.05%) was added to the

  10. Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice

    NARCIS (Netherlands)

    Schonewille, Marleen; de Boer, Jan Freark; Mele, Laura; Wolters, Henk; Bloks, Vincent W.; Wolters, Justina C.; Kuivenhoven, Jan A.; Tietge, Uwe J. F.; Brufau, Gemma; Groen, Albert K.

    2016-01-01

    Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we

  11. Comparison of kinetic properties of amine oxidases from sainfoin and lentil and immunochemical characterization of copper/quinoprotein amine oxidases.

    Science.gov (United States)

    Zajoncová, L; Frébort, I; Luhová, L; Sebela, M; Galuszka, P; Pec, P

    1999-01-01

    Kinetic properties of novel amine oxidase isolated from sainfoin (Onobrychis viciifolia) were compared to those of typical plant amine oxidase (EC 1.4.3.6) from lentil (Lens culinaris). The amine oxidase from sainfoin was active toward substrates, such as 1,5-diaminopentane (cadaverine) with K(m) of 0.09 mM and 1,4-diaminobutane (putrescine) with K(m) of 0.24 mM. The maximum rate of oxidation for cadaverine at saturating concentration was 2.7 fold higher than that of putrescine. The amine oxidase from lentil had the maximum rate for putrescine comparable to the rate of sainfoin amine oxidase with the same substrate. Both amine oxidases, like other plant Cu-amine oxidases, were inhibited by substrate analogs (1,5-diamino-3-pentanone, 1,4-diamino-2-butanone and aminoguanidine), Cu2+ chelating agents (diethyltriamine, 1,10-phenanthroline, 8-hydroxyquinoline, 2,2'-bipyridyl, imidazole, sodium cyanide and sodium azide), some alkaloids (L-lobeline and cinchonine), some lathyrogens (beta-aminopropionitrile and aminoacetonitrile) and other inhibitors (benzamide oxime, acetone oxime, hydroxylamine and pargyline). Tested by Ouchterlony's double diffusion in agarose gel, polyclonal antibodies against the amine oxidase from sainfoin, pea and grass pea cross-reacted with amine oxidases from several other Fabaceae and from barley (Hordeum vulgare) of Poaceae, while amine oxidase from the filamentous fungus Aspergillus niger did not cross-react at all. However, using Western blotting after SDS-PAGE with rabbit polyclonal antibodies against the amine oxidase from Aspergillus niger, some degree of similarity of plant amine oxidases from sainfoin, pea, field pea, grass pea, fenugreek, common melilot, white sweetclover and Vicia panonica with the A. niger amine oxidase was confirmed.

  12. ACAT inhibitors: the search for novel cholesterol lowering agents.

    Science.gov (United States)

    Pal, Palash; Gandhi, Hardik; Giridhar, Rajani; Yadav, Mange Ram

    2013-06-01

    Increased level of serum cholesterol (hyperlipidemia) is the most significant risk factor for the development of atherosclerosis. Cholesterol levels are affected by factors such as rate of endogenous cholesterol synthesis, biliary cholesterol excretion and dietary cholesterol absorption. Acyl CoA: Cholesterol O-acyl transferases (ACAT) are a small family of enzymes that catalyze cholesterol esterification and cholesterol absorption in intestinal mucosal cells and maintain the cholesterol homeostasis in the blood. Inhibition of the ACAT enzymes is one of the attractive targets to treat hyperlipidemia. Literature survey shows that structurally diverse compounds possess ACAT inhibitory properties. In this review, a comprehensive presentation of the literature on diverse ACAT inhibitors has been given.

  13. Multitarget sensing of glucose and cholesterol based on Janus hydrogel microparticles.

    Science.gov (United States)

    Sun, Xiao-Ting; Zhang, Ying; Zheng, Dong-Hua; Yue, Shuai; Yang, Chun-Guang; Xu, Zhang-Run

    2017-06-15

    A visualized sensing method for glucose and cholesterol was developed based on the hemispheres of the same Janus hydrogel microparticles. Single-phase and Janus hydrogel microparticles were both generated using a centrifugal microfluidic chip. For glucose sensing, concanavalin A and fluorescein labeled dextran used for competitive binding assay were encapsulated in alginate microparticles, and the fluorescence of the microparticles was positively correlated with glucose concentration. For cholesterol sensing, the microparticles embedded with γ-Fe 2 O 3 nanoparticles were used as catalyst for the oxidation of 3,3',5,5'-Tetramethylbenzidine by H 2 O 2 , an enzymatic hydrolysis product of cholesterol. And the color transition was more sensitive in the microparticles than in solutions, indicating the microparticles are more applicable for visualized determination. Furthermore, Janus microparticles were employed for multitarget sensing in the two hemespheres, and glucose and cholesterol were detected within the same microparticles without obvious interference. Besides, the particles could be manipulated by an external magnetic field. The glucose and cholesterol levels were measured in human serum utilizing the microparticles, which confirmed the potential application of the microparticles in real sample detection. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Basolateral cholesterol depletion alters Aquaporin-2 post-translational modifications and disrupts apical plasma membrane targeting.

    Science.gov (United States)

    Moeller, Hanne B; Fuglsang, Cecilia Hvitfeldt; Pedersen, Cecilie Nøhr; Fenton, Robert A

    2018-01-01

    Apical plasma membrane accumulation of the water channel Aquaporin-2 (AQP2) in kidney collecting duct principal cells is critical for body water homeostasis. Posttranslational modification (PTM) of AQP2 is important for regulating AQP2 trafficking. The aim of this study was to determine the role of cholesterol in regulation of AQP2 PTM and in apical plasma membrane targeting of AQP2. Cholesterol depletion from the basolateral plasma membrane of a collecting duct cell line (mpkCCD14) using methyl-beta-cyclodextrin (MBCD) increased AQP2 ubiquitylation. Forskolin, cAMP or dDAVP-mediated AQP2 phosphorylation at Ser269 (pS269-AQP2) was prevented by cholesterol depletion from the basolateral membrane. None of these effects on pS269-AQP2 were observed when cholesterol was depleted from the apical side of cells, or when MBCD was applied subsequent to dDAVP stimulation. Basolateral, but not apical, MBCD application prevented cAMP-induced apical plasma membrane accumulation of AQP2. These studies indicate that manipulation of the cholesterol content of the basolateral plasma membrane interferes with AQP2 PTM and subsequently regulated apical plasma membrane targeting of AQP2. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Modulation of NADPH oxidase activity by known uraemic retention solutes

    DEFF Research Database (Denmark)

    Schulz, Anna Marta; Terne, Cindy; Jankowski, Vera

    2014-01-01

    BACKGROUND: Uraemia and cardiovascular disease appear to be associated with an increased oxidative burden. One of the key players in the genesis of reactive oxygen species (ROS) is nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Based on initial experiments demonstrating a decreased...... inhibitory effect on NADPH oxidase activity in the presence of plasma from patients with CKD-5D after dialysis compared with before dialysis, we investigated the effect of 48 known and commercially available uraemic retention solutes on the enzymatic activity of NADPH oxidase. METHODS: Mononuclear leucocytes...... chloride (DPI), an inhibitor of NADPH oxidase. The effect on enzymatic activity of NADPH oxidase was quantified within an incubation time of 120 min. RESULTS: Thirty-nine of the 48 uraemic retention solutes tested had a significant decreasing effect on NADPH oxidase activity. Oxalate has been characterized...

  16. Multipolar interference effects in nanophotonics

    CERN Document Server

    Liu, Wei

    2016-01-01

    Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows to describe the scattering intensity and radiation pattern through interferences of dominating excited multipole modes. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here we review the multipolar interference effects in metallic, metal-dielectric, and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and nonradiating optical anapoles. We further discuss other types of possible ...

  17. Quantum Erasure: Quantum Interference Revisited

    OpenAIRE

    Walborn, Stephen P.; Cunha, Marcelo O. Terra; Pádua, Sebastião; Monken, Carlos H.

    2005-01-01

    Recent experiments in quantum optics have shed light on the foundations of quantum physics. Quantum erasers - modified quantum interference experiments - show that quantum entanglement is responsible for the complementarity principle.

  18. Nuclear receptors in control of cholesterol transport

    NARCIS (Netherlands)

    van der Veen, Jelske Nynke

    2007-01-01

    Cholesterol is een structurele component van celmembranen en een grondstof voor de aanmaak van steroïde hormonen en galzouten en vervult dus een aantal essentiële fysiologische functies. Een goede balans van cholesterol opname, synthese, afbraak en uitscheiding is noodzakelijk, omdat verhoogde

  19. Chemical activity of cholesterol in membranes.

    Science.gov (United States)

    Radhakrishnan, A; McConnell, H M

    2000-07-18

    Measurements are reported for the rate constants for the release of cholesterol (and dihydrocholesterol) to beta-cyclodextrin from mixtures with phospholipids in homogeneous monolayers at constant pressure at the air-water interface. In each mixture, it is found that the release rate shows a sharp decrease as the cholesterol concentration in the monolayer decreases through a composition corresponding to the stoichiometry of a cholesterol-phospholipid complex. The stoichiometry of the complex was established previously by the position of a sharp cusp in the thermodynamic phase diagram of each mixture and also by a minimum in average molecular area versus composition measurements. A theoretical model used earlier to account for the phase diagrams predicts the chemical potential and chemical activity of cholesterol in these mixtures. The calculated chemical activity also shows a sharp change at the complex stoichiometry in homogeneous monolayers. The similarities in change of observed release rate and calculated chemical activity are expected from reaction rate theory where the release rate is proportional to the cholesterol chemical activity. The chemical activity of cholesterol as determined by complex formation between some phospholipids and cholesterol in the plasma membrane of cells may serve a regulatory function with respect to intracellular cholesterol transport and biosynthesis.

  20. Evaluating computational models of cholesterol metabolism

    NARCIS (Netherlands)

    Paalvast, Yared; Kuivenhoven, Jan Albert; Groen, Albert K.

    2015-01-01

    Regulation of cholesterol homeostasis has been studied extensively during the last decades. Many of the metabolic pathways involved have been discovered. Yet important gaps in our knowledge remain. For example, knowledge on intracellular cholesterol traffic and its relation to the regulation of

  1. HDL (Good), LDL (Bad) Cholesterol and Triglycerides

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More HDL (Good), LDL (Bad) Cholesterol and Triglycerides Updated:Feb 19,2018 Cholesterol isn’t just something that sits in your body like fat around your waist. It’s carried through your bloodstream ...

  2. Role of cholesterol in Mycobacterium tuberculosis infection.

    Science.gov (United States)

    Miner, Maurine D; Chang, Jennifer C; Pandey, Amit K; Sassetti, Christopher M; Sherman, David R

    2009-06-01

    Mycobacterium tuberculosis (MTB) acquisition and utilization of nutrients within the host cell is poorly understood, although it has been hypothesized that host lipids probably play an important role in MTB survival. Cholesterol has recently been identified as an important lipid for mycobacterial infection. The mce4 transport system is required for cholesterol import into bacterial cells, and deletion of mce4 locus resulted in severe attenuation in a chronic mouse model of infection. However, it has remained unclear what additional bacterial functions were required for utilization of this sterol. We have found that the igr locus, which was previously found essential for intracellular growth and virulence of MTB, is required for cholesterol metabolism: igr-deficient bacteria cannot grow using cholesterol as a primary carbon source. The growth-inhibitory effect of cholesterol in vitro depends on cholesterol import, as the delta igr mutant growth defect during the early phase of disease is completely suppressed by mutating mce4, implicating cholesterol intoxication as the primary mechanism of attenuation. We conclude that M. tuberculosis metabolizes cholesterol throughout the course of infection, and that degradation of this sterol is crucial for bacterial persistence.

  3. Cholesterol: a Century of Research and Debate

    Directory of Open Access Journals (Sweden)

    Mathew B C

    2008-01-01

    Full Text Available To The Editor: The excellent article by Dr Elmehdawi RR entitled “Hypolipidemia: A word of caution” has once again shown the multifaceted properties of cholesterol which is the most highly decorated molecule in biology [1]. Thirteen nobel prizes have been awarded to scientists who devoted major parts of their careers to cholesterol [2].

  4. Cholesterol efflux is differentially regulated in neurons and astrocytes: implications for brain cholesterol homeostasis

    Science.gov (United States)

    Chen, Jing; Zhang, Xiaolu; Kusumo, Handojo; Costa, Lucio G.; Guizzetti, Marina

    2012-01-01

    Disruption of cholesterol homeostasis in the central nervous system (CNS) has been associated with neurological, neurodegenerative, and neurodevelopmental disorders. The CNS is a closed system with regard to cholesterol homeostasis, as cholesterol-delivering lipoproteins from the periphery cannot pass the blood-brain-barrier and enter the brain. Different cell types in the brain have different functions in the regulation of cholesterol homeostasis, with astrocytes producing and releasing apolipoprotein E and lipoproteins, and neurons metabolizing cholesterol to 24(S)-hydroxycholesterol. We present evidence that astrocytes and neurons adopt different mechanisms also in regulating cholesterol efflux. We found that in astrocytes cholesterol efflux is induced by both lipid-free apolipoproteins and lipoproteins, while cholesterol removal from neurons is triggered only by lipoproteins. The main pathway by which apolipoproteins induce cholesterol efflux is through ABCA1. By upregulating ABCA1 levels and by inhibiting its activity and silencing its expression, we show that ABCA1 is involved in cholesterol efflux from astrocytes but not from neurons. Furthermore, our results suggest that ABCG1 is involved in cholesterol efflux to apolipoproteins and lipoproteins from astrocytes but not from neurons, while ABCG4, whose expression is much higher in neurons than astrocytes, is involved in cholesterol efflux from neurons but not astrocytes. These results indicate that different mechanisms regulate cholesterol efflux from neurons and astrocytes, reflecting the different roles that these cell types play in brain cholesterol homeostasis. These results are important in understanding cellular targets of therapeutic drugs under development for the treatments of conditions associated with altered cholesterol homeostasis in the CNS. PMID:23010475

  5. Cholesterol Absorption and Synthesis in Vegetarians and Omnivores.

    Science.gov (United States)

    Lütjohann, Dieter; Meyer, Sven; von Bergmann, Klaus; Stellaard, Frans

    2018-02-10

    Vegetarian diets are considered health-promoting; however, a plasma cholesterol lowering effect is not always observed. We investigate the link between vegetarian-diet-induced alterations in cholesterol metabolism. We study male and female omnivores, lacto-ovo vegetarians, lacto vegetarians, and vegans. Cholesterol intake, absorption, and fecal sterol excretion are measured as well as plasma concentrations of cholesterol and noncholesterol sterols. These serve as markers for cholesterol absorption, synthesis, and catabolism. The biliary cholesterol secretion rate is estimated. Flux data are related to body weight. Individual vegetarian diet groups are statistically compared to the omnivore group. Lacto vegetarians absorb 44% less dietary cholesterol, synthesized 22% more cholesterol, and show no differences in plasma total and LDL cholesterol. Vegan subjects absorb 90% less dietary cholesterol, synthesized 35% more cholesterol, and have a similar plasma total cholesterol, but a 13% lower plasma LDL cholesterol. No diet-related differences in biliary cholesterol secretion and absorption are observed. Total cholesterol absorption is lower only in vegans. Total cholesterol input is similar under all vegetarian diets. Unaltered biliary cholesterol secretion and higher cholesterol synthesis blunt the lowered dietary cholesterol intake in vegetarians. LDL cholesterol is significantly lower only in vegans. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Gravity Responsive NADH Oxidase of the Plasma Membrane

    Science.gov (United States)

    Morre, D. James (Inventor)

    2002-01-01

    A method and apparatus for sensing gravity using an NADH oxidase of the plasma membrane which has been found to respond to unit gravity and low centrifugal g forces. The oxidation rate of NADH supplied to the NADH oxidase is measured and translated to represent the relative gravitational force exerted on the protein. The NADH oxidase of the plasma membrane may be obtained from plant or animal sources or may be produced recombinantly.

  7. Cholesterol-lowering effect of plant sterols.

    Science.gov (United States)

    AbuMweis, Suhad S; Jones, Peter J H

    2008-12-01

    Plant sterols are plant components that have a chemical structure similar to cholesterol except for the addition of an extra methyl or ethyl group; however, plant sterol absorption in humans is considerably less than that of cholesterol. In fact, plant sterols reduce cholesterol absorption and thus reduce circulating levels of cholesterol. Earlier studies that have tested the efficacy of plant sterols as cholesterol-lowering agents incorporated plant sterols into fat spreads. Later on, plant sterols were added to other food matrices, including juices, nonfat beverages, milk and yogurt, cheese, meat, croissants and muffins, and cereal and chocolate bars. The beneficial physiologic effects of plant sterols could be further enhanced by combining them with other beneficial substances, such as olive and fish oils, fibers, and soy proteins, or with exercise. The addition of plant sterols to the diet is suggested by health experts as a safe and effective way to reduce the risk of coronary heart disease.

  8. Trapping crystal nucleation of cholesterol monohydrate

    DEFF Research Database (Denmark)

    Solomonov, I.; Weygand, M.J.; Kjær, K.

    2005-01-01

    Crystalline nucleation of cholesterol at the air-water interface has been studied via grazing incidence x-ray diffraction using synchrotron radiation. The various stages of cholesterol molecular assembly from monolayer to three bilayers incorporating interleaving hydrogen-bonded water layers...... in a monoclinic cholesterol . H2O phase, has been monitored and their structures characterized to near atomic resolution. Crystallographic evidence is presented that this multilayer phase is similar to that of a reported metastable cholesterol phase of undetermined structure obtained from bile before...... transformation to the triclinic phase of cholesterol . H2O, the thermodynamically stable macroscopic form. According to grazing incidence x-ray diffraction measurements and crystallographic data, a transformation from the monoclinic film structure to a multilayer of the stable monohydrate phase involves...

  9. How much in vitro cholesterol reducing activity of lactobacilli predicts their in vivo cholesterol function?

    Directory of Open Access Journals (Sweden)

    Golnoush Madani

    2013-01-01

    Results: No cholesterol assimilation was detected by growth and incubation of the active culture in either of the medium. Thus, in vivo cholesterol function of LA7 was not caused by cholesterol consumption. A comprehensive review of literature on the related studies also showed that there are other documented studies which evidenced the uncertainty of the direct relation between in vitro and in vivo studies. Conclusion: Cholesterol removal from the cultured media may not be considered as an appropriate integral index for selection of Lactobacillus strains with cholesterol-lowering activity.

  10. Effects of psyllium on plasma total and lipoprotein cholesterol and hepatic cholesterol in hamsters fed n-3 PUFA or n-6 PUFA with high cholesterol levels.

    Science.gov (United States)

    Liu, Young-Chau; Liu, Shyun-Yeu; Lin, Mei-Huei

    2004-01-01

    This study was conducted to determine whether psyllium is known to alter cholesterol metabolism modulate the hypercholesterolemic effect of a high cholesterol, n-3 polyunsaturated fatty acids (PUFA) diet in hamsters. Concentrations of plasma, hepatic total cholesterol and lipoprotein cholesterol were measured in male hamsters fed an n-3 PUFA plus psyllium (8%, wt/wt) diet combined with variable levels of cholesterol (0, 0.05, 0.1%, wt/wt) or a cholesterol-enriched (0.2%, wt/wt) n-3 PUFA or n-6 PUFA diet that contained either 8% methyl cellulose or psyllium for 4 weeks. In the n-3 PUFA-fed hamsters, we have found that psyllium was able to reduce plasma total cholesterol and low density lipoprotein (LDL)-cholesterol significantly when 0.1% cholesterol was added to the diet. In contrast, the effects of psyllium were not seen in the n-3 PUFA-fed hamsters without dietary cholesterol or with 0.05% dietary cholesterol. However, no matter in the presence of psyllium or not, the increase of plasma total cholesterol, very-low-density lipoprotein (VLDL)-cholesterol, LDL-cholesterol and high-density lipoprotein (HDL)-cholesterol levels was depend on the content of dietary cholesterol. Although the cholesterol diet increased the liver total cholesterol level, 80 g psyllium/kg diet resulted in a significantly lower concentration of liver total cholesterol in the cholesterol-fed hamsters. In the second experiment, we have also found that psyllium feeding lowered significantly plasma total cholesterol and VLDL-cholesterol concentrations in hamsters fed n-3 PUFA but not in those fed n-6 PUFA. However, the levels of plasma total cholesterol, VLDL-cholesterol and LDL-cholesterol levels of the (n-6) PUFA-fed hamsters were significantly lower than those in the (n-3) PUFA-fed hamsters in the absence or presence of dietary psyllium. Our data also showed that hamsters fed both high-cholesterol n-3 PUFA and n-6 PUFA diets had a significant decrease in hepatic cholesterol with intake of

  11. Continuous transport of a small fraction of plasma membrane cholesterol to endoplasmic reticulum regulates total cellular cholesterol.

    Science.gov (United States)

    Infante, Rodney Elwood; Radhakrishnan, Arun

    2017-04-17

    Cells employ regulated transport mechanisms to ensure that their plasma membranes (PMs) are optimally supplied with cholesterol derived from uptake of low-density lipoproteins (LDL) and synthesis. To date, all inhibitors of cholesterol transport block steps in lysosomes, limiting our understanding of post-lysosomal transport steps. Here, we establish the cholesterol-binding domain 4 of anthrolysin O (ALOD4) as a reversible inhibitor of cholesterol transport from PM to endoplasmic reticulum (ER). Using ALOD4, we: (1) deplete ER cholesterol without altering PM or overall cellular cholesterol levels; (2) demonstrate that LDL-derived cholesterol travels from lysosomes first to PM to meet cholesterol needs, and subsequently from PM to regulatory domains of ER to suppress activation of SREBPs, halting cholesterol uptake and synthesis; and (3) determine that continuous PM-to-ER cholesterol transport allows ER to constantly monitor PM cholesterol levels, and respond rapidly to small declines in cellular cholesterol by activating SREBPs, increasing cholesterol uptake and synthesis.

  12. Brain Monoamine Oxidase A Activity Predicts Trait Aggression

    National Research Council Canada - National Science Library

    Alia-Klein, Nelly; Goldstein, Rita Z; Kriplani, Aarti; Logan, Jean; Tomasi, Dardo; Williams, Benjamin; Telang, Frank; Shumay, Elena; Biegon, Anat; Craig, Ian W; Henn, Fritz; Wang, Gene-Jack; Volkow, Nora D; Fowler, Joanna S

    2008-01-01

    The genetic deletion of monoamine oxidase A (MAO A), an enzyme that breaks down the monoamine neurotransmitters norepinephrine, serotonin, and dopamine, produces aggressive phenotypes across species...

  13. [Xanthine oxidase deficiency (hereditary xanthinuria), molybdenum cofactor deficiency].

    Science.gov (United States)

    Sumi, S; Wada, Y

    1996-12-01

    Hereditary xanthinuria is a rare autosomal recessive disorder, with xanthine oxidase deficiency. Patients often display renal symptoms because they excrete a large amounts of xanthine in urine. An high-fluid-intake, alow-purine-food, and alkalinization of urine are effective in the patients. Molybdenum cofactor is essential for xanthine oxidase, sulfite oxidase and aldehyde oxidase. Patients with molybdenum cofactor deficiency display severe neurological symptoms, such as severe convulsions. The patients increase urinary excretions of xanthine and sulfite. Treatments are ineffective for neurological symptoms.

  14. Study on dioxygen reduction by mutational modifications of the hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Hirotoshi; Kurita, Daisuke; Kataoka, Kunishige; Sakurai, Takeshi, E-mail: tsakurai@se.kanazawa-u.ac.jp

    2014-07-18

    Highlights: • Proton transport pathway in bilirubin oxidase was mutated. • Two intermediates in the dioxygen reduction steps were trapped and characterized. • A specific glutamate for dioxygen reduction by multicopper oxidases was identified. - Abstract: The hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase is constructed with Glu463 and water molecules to transport protons for the four-electron reduction of dioxygen. Substitutions of Glu463 with Gln or Ala were attributed to virtually complete loss or significant reduction in enzymatic activities due to an inhibition of the proton transfer steps to dioxygen. The single turnover reaction of the Glu463Gln mutant afforded the highly magnetically interacted intermediate II (native intermediate) with a broad g = 1.96 electron paramagnetic resonance signal detectable at cryogenic temperatures. Reactions of the double mutants, Cys457Ser/Glu463Gln and Cys457Ser/Glu463Ala afforded the intermediate I (peroxide intermediate) because the type I copper center to donate the fourth electron to dioxygen was vacant in addition to the interference of proton transport due to the mutation at Glu463. The intermediate I gave no electron paramagnetic resonance signal, but the type II copper signal became detectable with the decay of the intermediate I. Structural and functional similarities between multicopper oxidases are discussed based on the present mutation at Glu463 in bilirubin oxidase.

  15. Alterations in the homeostasis of phospholipids and cholesterol by antitumor alkylphospholipids

    Directory of Open Access Journals (Sweden)

    Segovia Josefa L

    2010-03-01

    Full Text Available Abstract The alkylphospholipid analog miltefosine (hexadecylphosphocholine is a membrane-directed antitumoral and antileishmanial drug belonging to the alkylphosphocholines, a group of synthetic antiproliferative agents that are promising candidates in anticancer therapy. A variety of mechanisms have been suggested to explain the actions of these compounds, which can induce apoptosis and/or cell growth arrest. In this review, we focus on recent advances in our understanding of the actions of miltefosine and other alkylphospholipids on the human hepatoma HepG2 cell line, with a special emphasis on lipid metabolism. Results obtained in our laboratory indicate that miltefosine displays cytostatic activity and causes apoptosis in HepG2 cells. Likewise, treatment with miltefosine produces an interference with the biosynthesis of phosphatidylcholine via both CDP-choline and phosphatidylethanolamine methylation. With regard to sphingolipid metabolism, miltefosine hinders the formation of sphingomyelin, which promotes intracellular accumulation of ceramide. We have demonstrated for the first time that treatment with miltefosine strongly impedes the esterification of cholesterol and that this effect is accompanied by a considerable increase in the synthesis of cholesterol, which leads to higher levels of cholesterol in the cells. Indeed, miltefosine early impairs cholesterol transport from the plasma membrane to the endoplasmic reticulum, causing a deregulation of cholesterol homeostasis. Similar to miltefosine, other clinically-relevant synthetic alkylphospholipids such as edelfosine, erucylphosphocholine and perifosine show growth inhibitory effects on HepG2 cells. All the tested alkylphospholipids also inhibit the arrival of plasma-membrane cholesterol to the endoplasmic reticulum, which induces a significant cholesterogenic response in these cells, involving an increased gene expression and higher levels of several proteins related to the pathway of

  16. Computing reduction potential of Glucose Oxidase Enzyme

    OpenAIRE

    Tamura, Kazuma; Muhamad, A. Martoprawiro

    2015-01-01

    Glucose oxidase (GOx) is an enzyme and it is an important molecule to understand the energy trans-fer system in our body. Flavin adenine dinucleotide (FAD) is co-enzyme and it is frequently combined with GOx. GOx helps reduction or oxidation of FAD. Redox would not happen naturally unless FAD is combined with GOx, therefore understanding the effect of electrostatic environment which is made by atoms of GOx is one of the most important factors to decide the reduction potential of GOx-FAD. In t...

  17. Cholesterol: Top Five Foods to Lower Your Numbers

    Science.gov (United States)

    ... store-bought cookies, crackers and cakes, are particularly bad for your cholesterol levels. Trans fats raise LDL cholesterol, and lower high-density lipoprotein (HDL), the "good" cholesterol. Food labels report the content of trans ...

  18. Cholesterol Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/cholesteroltest.html Cholesterol Test To use the sharing features on this page, please enable JavaScript. What is a Cholesterol Test? Cholesterol is a waxy, fat-like substance ...

  19. High Cholesterol and Complementary Health Practices: What the Science Says

    Science.gov (United States)

    ... Health NCCIH Clinical Digest for health professionals High Cholesterol and Complementary Health Practices: What the Science Says ... chemically identical to the active ingredient in the cholesterol-lowering drug lovastatin. Available evidence on the cholesterol- ...

  20. Major Risk Factors for Heart Disease: High Blood Cholesterol

    Science.gov (United States)

    ... Major Risk Factors for Heart Disease High Blood Cholesterol High blood cholesterol is another major risk factor for heart disease ... can do something about. The higher your blood cholesterol level, the greater your risk for developing heart ...

  1. Lysyl oxidases regulate fibrillar collagen remodelling in idiopathic pulmonary fibrosis

    Science.gov (United States)

    White, Eric S.

    2017-01-01

    ABSTRACT Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung with few effective therapeutic options. Structural remodelling of the extracellular matrix [i.e. collagen cross-linking mediated by the lysyl oxidase (LO) family of enzymes (LOX, LOXL1-4)] might contribute to disease pathogenesis and represent a therapeutic target. This study aimed to further our understanding of the mechanisms by which LO inhibitors might improve lung fibrosis. Lung tissues from IPF and non-IPF subjects were examined for collagen structure (second harmonic generation imaging) and LO gene (microarray analysis) and protein (immunohistochemistry and western blotting) levels. Functional effects (collagen structure and tissue stiffness using atomic force microscopy) of LO inhibitors on collagen remodelling were examined in two models, collagen hydrogels and decellularized human lung matrices. LOXL1/LOXL2 gene expression and protein levels were increased in IPF versus non-IPF. Increased collagen fibril thickness in IPF versus non-IPF lung tissues correlated with increased LOXL1/LOXL2, and decreased LOX, protein expression. β-Aminoproprionitrile (β-APN; pan-LO inhibitor) but not Compound A (LOXL2-specific inhibitor) interfered with transforming growth factor-β-induced collagen remodelling in both models. The β-APN treatment group was tested further, and β-APN was found to interfere with stiffening in the decellularized matrix model. LOXL1 activity might drive collagen remodelling in IPF lungs. The interrelationship between collagen structural remodelling and LOs is disrupted in IPF lungs. Inhibition of LO activity alleviates fibrosis by limiting fibrillar collagen cross-linking, thereby potentially impeding the formation of a pathological microenvironment in IPF. PMID:29125826

  2. Lysyl oxidases regulate fibrillar collagen remodelling in idiopathic pulmonary fibrosis.

    Science.gov (United States)

    Tjin, Gavin; White, Eric S; Faiz, Alen; Sicard, Delphine; Tschumperlin, Daniel J; Mahar, Annabelle; Kable, Eleanor P W; Burgess, Janette K

    2017-11-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung with few effective therapeutic options. Structural remodelling of the extracellular matrix [i.e. collagen cross-linking mediated by the lysyl oxidase (LO) family of enzymes (LOX, LOXL1-4)] might contribute to disease pathogenesis and represent a therapeutic target. This study aimed to further our understanding of the mechanisms by which LO inhibitors might improve lung fibrosis. Lung tissues from IPF and non-IPF subjects were examined for collagen structure (second harmonic generation imaging) and LO gene (microarray analysis) and protein (immunohistochemistry and western blotting) levels. Functional effects (collagen structure and tissue stiffness using atomic force microscopy) of LO inhibitors on collagen remodelling were examined in two models, collagen hydrogels and decellularized human lung matrices. LOXL1/LOXL2 gene expression and protein levels were increased in IPF versus non-IPF. Increased collagen fibril thickness in IPF versus non-IPF lung tissues correlated with increased LOXL1/LOXL2, and decreased LOX, protein expression. β-Aminoproprionitrile (β-APN; pan-LO inhibitor) but not Compound A (LOXL2-specific inhibitor) interfered with transforming growth factor-β-induced collagen remodelling in both models. The β-APN treatment group was tested further, and β-APN was found to interfere with stiffening in the decellularized matrix model. LOXL1 activity might drive collagen remodelling in IPF lungs. The interrelationship between collagen structural remodelling and LOs is disrupted in IPF lungs. Inhibition of LO activity alleviates fibrosis by limiting fibrillar collagen cross-linking, thereby potentially impeding the formation of a pathological microenvironment in IPF. © 2017. Published by The Company of Biologists Ltd.

  3. Endogenous cholesterol synthesis, fecal steroid excretion and serum lanosterol in subjects with high or low response of serum cholesterol to dietary cholesterol

    NARCIS (Netherlands)

    Beynen, A.C.; Katan, M.B.; Gent, van C.M.

    1986-01-01

    In this study we addressed the question whether hypo- and hyper-responders to dietary cholesterol differ with regard to the flexibility of endogenous cholesterol synthesis after changes in cholesterol intake. Whole-body cholesterol synthesis was measured as faecal excretion of neutral steroids and

  4. The heme-copper oxidase family consists of three distinct types of terminal oxidases and is related to nitric oxide reductase

    NARCIS (Netherlands)

    van der Oost, J.; de Boer, A P; de Gier, J.-W.; Zumft, W.G.; Stouthamer, A.H.; van Spanning, R J

    1994-01-01

    Among aerobic prokaryotes, many different terminal oxidase complexes have been described. Sequence comparison has revealed that the aa3-type cytochrome c oxidase and the bo3-type quinol oxidase are variations on the same theme: the heme-copper oxidase. A third member of this family has recently been

  5. Genetic therapies to lower cholesterol.

    Science.gov (United States)

    Khoo, Bernard

    2015-01-01

    This review surveys the state-of-the-art in genetic therapies for familial hypercholesterolaemia (FH), caused most commonly by mutations in the LDL receptor (LDLR) gene. FH manifests as highly elevated low density lipoprotein (LDL) cholesterol levels and consequently accelerated atherosclerosis. Modern pharmacological therapies for FH are insufficiently efficacious to prevent premature cardiovascular disease, can cause significant adverse effects and can be expensive. Genetic therapies for FH have been mooted since the mid 1990s but gene replacement strategies using viral vectors have so far been unsuccessful. Other strategies involve knocking down the expression of Apolipoprotein B100 (APOB100) and the protease PCSK9 which designates LDLR for degradation. The antisense oligonucleotide mipomersen, which knocks down APOB100, is currently marketed (with restrictions) in the USA, but is not approved in Europe due to its adverse effects. To address this problem, we have devised a novel therapeutic concept, APO-skip, which is based on modulation of APOB splicing, and which has the potential to deliver a cost-effective, efficacious and safe therapy for FH. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Physiological and pathological implications of cholesterol.

    Science.gov (United States)

    Cortes, Victor A; Busso, Dolores; Maiz, Alberto; Arteaga, Antonio; Nervi, Flavio; Rigotti, Attilio

    2014-01-01

    Cholesterol has evolved to fulfill sophisticated biophysical, cell signaling and endocrine requirements of animal systems. At a cellular level, cholesterol is found in membranes, where it increases both bilayer stiffness and impermeability to water and ions. Furthermore, cholesterol is integrated into specialized lipid-protein membrane microdomains with critical topographical and signaling functions. At an organismal level, cholesterol is the precursor for all steroid hormones, including gluco- and mineralo-corticoids, sex hormones and vitamin D, all of which regulate carbohydrate, sodium, reproductive and bone homeostasis, respectively. This sterol is also the precursor for bile acids, which are important for intestinal absorption of dietary lipids as well as energy and glucose metabolic regulation. Importantly, complex mechanisms maintain cholesterol within physiological ranges and the disregulation of these mechanisms results in embryonic or adult diseases, caused by either excessive or reduced tissue cholesterol levels. The causative role of cholesterol in these diseases has been demonstrated by diverse genetic and pharmacologic animal models that are commented in this review.

  7. Acyl-coenzyme A:cholesterol acyltransferases

    OpenAIRE

    Chang, Ta-Yuan; Li, Bo-Liang; Chang, Catherine C. Y.; Urano, Yasuomi

    2009-01-01

    The enzymes acyl-coenzyme A (CoA):cholesterol acyltransferases (ACATs) are membrane-bound proteins that utilize long-chain fatty acyl-CoA and cholesterol as substrates to form cholesteryl esters. In mammals, two isoenzymes, ACAT1 and ACAT2, encoded by two different genes, exist. ACATs play important roles in cellular cholesterol homeostasis in various tissues. This chapter summarizes the current knowledge on ACAT-related research in two areas: 1) ACAT genes and proteins and 2) ACAT enzymes as...

  8. Biotechniques in Electrochemical Determination of Cholesterol: Review

    Directory of Open Access Journals (Sweden)

    VIKAS

    2007-09-01

    Full Text Available With rising healthcare costs and to improve patient care, diagnostic laboratories have been challenged to develop new tests that are reliable, cost–effective and accurate and to optimize existing protocols by making them faster and more economical. Determination of serum total cholesterol is one of the most vital biochemical parameters in healthcare. With the availability of new materials associated with new sensing techniques has led to remarkable innovations in the design and construction of cholesterol biosensors. The present review describes the specifications of most of the electrochemical cholesterol biosensors reported till date.

  9. Cholesterol homeostasis in cardiovascular disease and recent advances in measuring cholesterol signatures.

    Science.gov (United States)

    Seo, Hong Seog; Choi, Man Ho

    2015-09-01

    Despite the biochemical importance of cholesterol, its abnormal metabolism has serious cellular consequences that lead to endocrine disorders such as cardiovascular disease (CVD). Nevertheless, the impact of blood cholesterol as a CVD risk factor is still debated, and treatment with cholesterol-lowering drugs remains controversial, particularly in older patients. Although, the prevalence of CVD increases with age, the underlying mechanisms for this phenomenon are not well understood, and metabolic changes have not been confirmed as predisposing factors of atherogenesis. The quantification of circulating biomarkers for cholesterol homeostasis is therefore warranted, and reference values for cholesterol absorption and synthesis should be determined in order to establish CVD risk factors. The traditional lipid profile is often derived rather than directly measured and lacks a universal standard to interpret the results. In contrast, mass spectrometry-based cholesterol profiling can accurately measure free cholesterol as a biologically active component. This approach allows to detect alterations in various metabolic pathways that control cholesterol homeostasis, by quantitative analysis of cholesterol and its precursors/metabolites as well as dietary sterols. An overview of the mechanism of cholesterol homeostasis under different physiological conditions may help to identify predictive biomarkers of concomitant atherosclerosis and conventional CVD risk factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Cellular Cholesterol Regulates Ubiquitination and Degradation of the Cholesterol Export Proteins ABCA1 and ABCG1*

    Science.gov (United States)

    Hsieh, Victar; Kim, Mi-Jurng; Gelissen, Ingrid C.; Brown, Andrew J.; Sandoval, Cecilia; Hallab, Jeannette C.; Kockx, Maaike; Traini, Mathew; Jessup, Wendy; Kritharides, Leonard

    2014-01-01

    The objective of this study was to examine the influence of cholesterol in post-translational control of ABCA1 and ABCG1 protein expression. Using CHO cell lines stably expressing human ABCA1 or ABCG1, we observed that the abundance of these proteins is increased by cell cholesterol loading. The response to increased cholesterol is rapid, is independent of transcription, and appears to be specific for these membrane proteins. The effect is mediated through cholesterol-dependent inhibition of transporter protein degradation. Cell cholesterol loading similarly regulates degradation of endogenously expressed ABCA1 and ABCG1 in human THP-1 macrophages. Turnover of ABCA1 and ABCG1 is strongly inhibited by proteasomal inhibitors and is unresponsive to inhibitors of lysosomal proteolysis. Furthermore, cell cholesterol loading inhibits ubiquitination of ABCA1 and ABCG1. Our findings provide evidence for a rapid, cholesterol-dependent, post-translational control of ABCA1 and ABCG1 protein levels, mediated through a specific and sterol-sensitive mechanism for suppression of transporter protein ubiquitination, which in turn decreases proteasomal degradation. This provides a mechanism for acute fine-tuning of cholesterol transporter activity in response to fluctuations in cell cholesterol levels, in addition to the longer term cholesterol-dependent transcriptional regulation of these genes. PMID:24500716

  11. Tissue storage and control of cholesterol metabolism in man on high cholesterol diets.

    Science.gov (United States)

    Quintão, E C; Brumer, S; Stechhahn, K

    1977-03-01

    The possibility of accumulation of tissue cholesterol in human beings submitted to high cholesterol feeding was investigated in liver biopsies and through fecal sterol balance studies. Feeding to 10 individuals 3.1 to 3.4 g/day of cholesterol for 3 weeks raised the mean serum level from 293 to 349 mg/100 ml, namely 19%, whereas the liver cholesterol content was 417 mg/100 g of wet weight. In 10 control cases eating 0.1--0.4 g/day of cholesterol serum cholesterol remained stable throughout the experimental period and the liver cholesterol content was 256 mg/100 g. Difference of liver colesterol level between the two groups was 62%. In 7 patients submitted to two periods of balance investigation on a cholesterol-free synthetic formula diet respectively prior to (PI) and after (PIII) eating the high cholesterol solid food from 4 to 15 weeks (PII), fecal steroid excretion in PIII exceeded PI in 3 patients. Such data are a direct evidence for the existence of an efficient system to release acutely stored cholesterol. In one patient bile acid excretion accounted for the difference between PIII and PI.

  12. Structure of the human lysyl oxidase gene

    Energy Technology Data Exchange (ETDEWEB)

    Haemaelaeinen, E.R.; Kemppainen, R.; Pihlajaniemi, T.; Kivirikko, K.I. (Univ. of Oulu (Finland))

    1993-09-01

    Lysyl oxidase (EC 1.4.3.13), an extracellular copper enzyme, initiates the crosslinking of collagens and elastin by catalyzing oxidative deamination of the [epsilon]-amino group in certain lysine and hydroxylysine residues. The authors report here that the human lysyl oxidase gene is about 15 kb in size and consists of seven exons. Transcription is initiated at one major site and four minor sites, and the first exon consists of 273 bp of untranslated sequences (calculated to the major site) and 631 bp of translated sequences, which accounts for about half of all the translated sequences of the gene. The seventh exon, on the other hand, codes for only the last codon of amino acid 416 and for amino acid 417, which are followed by the translation termination codon and the 3[prime] untranslated sequences. Exons 2-6 vary in size from 96to157 bp, and the introns from 331 bp to about 3.5 kb. The 5[prime] flanking region contains a TATA-like sequence at -30 relative to the major transcription initiation site and a CCAAT motif at -109. The 5[prime] flanking region and the downstream sequences present in the first exon and first intron contain altogether five possible binding sequences for Sp1, six for AP-2, one for AP-1, three of PEA3, three for MEP-1, and three CCCTCCC motifs, all of which may be involved in the regulation of the expression of the gene. 25 refs., 4 figs., 1 tab.

  13. Triglycerides, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol in rats exposed to premium motor spirit fumes.

    Science.gov (United States)

    Aberare, Ogbevire L; Okuonghae, Patrick; Mukoro, Nathaniel; Dirisu, John O; Osazuwa, Favour; Odigie, Elvis; Omoregie, Richard

    2011-06-01

    Deliberate and regular exposure to premium motor spirit fumes is common and could be a risk factor for liver disease in those who are occupationally exposed. A possible association between premium motor spirit fumes and plasma levels of triglyceride, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol using a rodent model could provide new insights in the pathology of diseases where cellular dysfunction is an established risk factor. The aim of this study was to evaluate the possible effect of premium motor spirit fumes on lipids and lipoproteins in workers occupationally exposed to premium motor spirit fumes using rodent model. Twenty-five Wister albino rats (of both sexes) were used for this study between the 4(th) of August and 7(th) of September, 2010. The rats were divided into five groups of five rats each. Group 1 rats were not exposed to premium motor spirit fumes (control group), group 2 rats were exposed for 1 hour daily, group 3 for 3 hours daily, group 4 for 5 hours daily and group 5 for 7 hours daily. The experiment lasted for a period of 4 weeks. Blood samples obtained from all the groups after 4 weeks of exposure were used for the estimation of plasma levels of triglyceride, total cholesterol, high density lipoprotein- cholesterol and low density lipoprotein- cholesterol. Results showed significant increase in means of plasma total cholesterol and low density lipoprotein levels (Plevel of high density lipoprotein, the ratio of low density lipoprotein to high density lipoprotein and the ratio of total cholesterol to high density lipoprotein did not differ significantly in exposed subjects when compared with the control group. These results showed that frequent exposure to petrol fumes may be highly deleterious to the liver cells.

  14. Molecular evolution of cytochrome bd oxidases across proteobacterial genomes.

    Science.gov (United States)

    Degli Esposti, Mauro; Rosas-Pérez, Tania; Servín-Garcidueñas, Luis Eduardo; Bolaños, Luis Manuel; Rosenblueth, Monica; Martínez-Romero, Esperanza

    2015-02-16

    This work is aimed to resolve the complex molecular evolution of cytochrome bd ubiquinol oxidase, a nearly ubiquitous bacterial enzyme that is involved in redox balance and bioenergetics. Previous studies have created an unclear picture of bd oxidases phylogenesis without considering the existence of diverse types of bd oxidases. Integrated approaches of genomic and protein analysis focused on proteobacteria have generated a molecular classification of diverse types of bd oxidases, which produces a new scenario for interpreting their evolution. A duplication of the original gene cluster of bd oxidase might have occurred in the ancestors of extant α-proteobacteria of the Rhodospirillales order, such as Acidocella, from which the bd-I type of the oxidase might have diffused to other proteobacterial lineages. In contrast, the Cyanide-Insensitive Oxidase type may have differentiated into recognizable subtypes after another gene cluster duplication. These subtypes are widespread in the genomes of α-, β-, and γ-proteobacteria, with occasional instances of lateral gene transfer. In resolving the evolutionary pattern of proteobacterial bd oxidases, this work sheds new light on the basal taxa of α-proteobacteria from which the γ-proteobacterial lineage probably emerged. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  15. Physiological roles of plastid terminal oxidase in plant stress ...

    Indian Academy of Sciences (India)

    The plastid terminal oxidase (PTOX) is a plastoquinol oxidase localized in the plastids of plants. It is able to transfer electrons from plastoquinone (PQ) to molecular oxygen with the formation of water. Recent studies have suggested that PTOX is beneficial for plants under environmental stresses, since it is involved in the ...

  16. Effect of heat treatment on polyphenol oxidase and peroxidase ...

    African Journals Online (AJOL)

    GREGO

    2006-12-18

    Dec 18, 2006 ... Hamdan AM (1975). Date polyphenol oxidase. M.Sc. Thesis, College of. Agriculture, University of Baghdad. Hasegawa S, Maier VP (1980). Polyphenol oxidase of dates. J. Agric. Food Chem. 28: 891-893. Gerhard K (1993). Métabolisme des végétaux. Physiologie et Biochimie. Ed. Française ISBN. France.

  17. Application of glucose oxidase for the production of metal ...

    African Journals Online (AJOL)

    The present study deals with the application of glucose oxidase (GOX) for the production of metal gluconates by fermentation method. It provides a method for the conversion of glucose into gluconic acid and its derivatives using the enzyme glucose oxidase (GOX). Due to the presence of calcium carbonate in fermentation ...

  18. Laboratory-evolved vanillyl-alcohol oxidase produces natural vanillin

    NARCIS (Netherlands)

    Heuvel, van den R.H.H.; Berg, van den W.A.M.; Rovida, S.; Berkel, van W.J.H.

    2004-01-01

    The flavoenzyme vanillyl-alcohol oxidase was subjected to random mutagenesis to generate mutants with enhanced reactivity to creosol (2-methoxy-4-methylphenol). The vanillyl-alcohol oxidase-mediated conversion of creosol proceeds via a two-step process in which the initially formed vanillyl alcohol

  19. 21 CFR 866.2420 - Oxidase screening test for gonorrhea.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oxidase screening test for gonorrhea. 866.2420... screening test for gonorrhea. (a) Identification. An oxidase screening test for gonorrhea is an in vitro... of gonorrhea. (b) Classification. Class III (premarket approval) (transitional device). (c) Date PMA...

  20. Structure and activity of Aspergillus nidulans copper amine oxidase

    DEFF Research Database (Denmark)

    McGrath, Aaron P; Mithieux, Suzanne M; Collyer, Charles A

    2011-01-01

    Aspergillus nidulans amine oxidase (ANAO) has the unusual ability among the family of copper and trihydroxyphenylalanine quinone-containing amine oxidases of being able to oxidize the amine side chains of lysine residues in large peptides and proteins. We show here that in common with the related...

  1. Application of glucose oxidase for the production of metal ...

    African Journals Online (AJOL)

    Chem

    2013-11-27

    Nov 27, 2013 ... The present study deals with the application of glucose oxidase (GOX) for the production of metal gluconates by fermentation method. It provides a method for the conversion of glucose into gluconic acid and its derivatives using the enzyme glucose oxidase (GOX). Due to the presence of calcium carbonate ...

  2. A dual enzymatic-biosensor for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages of diabetic mice: Evaluation of the diabetes-accelerated atherosclerosis risk

    Energy Technology Data Exchange (ETDEWEB)

    Huang Qilin; An Yarui; Tang Linlin; Jiang Xiaoli; Chen Hua; Bi Wenji [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Wang Zhongchuan [Department of Anorectal Surgery, Xinhua Hospital, Affiliated to School of Medicine of Shanghai Jiaotong University, Shanghai 200092 (China); Zhang Wen, E-mail: wzhang@chem.ecnu.edu.cn [Department of Chemistry, East China Normal University, Shanghai 200062 (China)

    2011-11-30

    evidences for diabetes-accelerate atherosclerosis. - Abstract: In this paper, a novel dual enzymatic-biosensor is described for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages (PMs) of diabetic mice to evaluate the risk of diabetes-accelerated atherosclerosis. The biosensor was constructed by a three-step method. First, a poly-thionine (PTH) film was assembled on the surface of glassy carbon electrode by cyclic voltammetric electropolymerization of thionine, which serves as an electron transfer mediator (ETM). Second, gold nanoparticles (GNPs) were covered on the surface of PTH facilitating the electron transfer between glucose oxidase (GOx), cholesterol oxidase (ChOx) and electrode. Finally, the enzymes, GOx, cholesterol esterase (ChE), and ChOx, were covalently attached to the PTH layer through a chitosan (CH) linker. The PTH coupled with GNPs provides good selectivity, high sensitivity and little crosstalk for the dual enzymatic-biosensor. The developed biosensor had good electrocatalytic activity toward the oxidations of glucose and cholesterol, exhibiting a linear range from 0.008 mM to 6.0 mM for glucose with a detection limit of 2.0 {mu}M, and a linear range from 0.002 mM to 1.0 mM for cholesterol with a detection limit of 0.6 {mu}M. The results of the diabetic mice demonstrated that the cholesterol level did not change obviously with the increase of glucose level in serum, while the cholesterol level was induced with the increase of the glucose level in PMs. Previous studies have shown that the large accumulation of cholesterol in macrophage could lead to macrophage foam cell formation, which is the hallmark of early atherosclerosis. This study provides useful further evidences for the development of diabetes-accelerated atherosclerosis.

  3. High-fat diet-induced reduction in nitric oxide-dependent arteriolar dilation in rats: role of xanthine oxidase-derived superoxide anion.

    Science.gov (United States)

    Erdei, Nóra; Tóth, Attila; Pásztor, Eniko T; Papp, Zoltán; Edes, István; Koller, Akos; Bagi, Zsolt

    2006-11-01

    Obesity frequently leads to the development of hypertension. We hypothesized that high-fat diet (HFD)-induced obesity impairs the endothelium-dependent dilation of arterioles. Male Wistar rats were fed with normal (control) or HFD (60% of saturated fat, for 10 wk). In rats with HFD, body weight, mean arterial blood pressure, and serum insulin, cholesterol, and glucose were elevated. In isolated gracilis muscle arterioles (diameter: approximately 160 microm) of HFD, rat dilations to ACh (at 1 microM, maximum: 83 +/- 3%) and histamine (at 10 microM, maximum: 16 +/- 4%) were significantly (P < 0.05) decreased compared with those of control responses (maximum: 90 +/- 2 and 46 +/- 4%, respectively). Dilations to the NO donor sodium nitroprusside were similar in the two groups. Inhibition of NO synthesis by N(omega)-nitro-l-arginine methyl ester reduced ACh- and histamine-induced dilations in control arterioles but had no effect on microvessels of HFD rats. The superoxide dismutase mimetic Tiron or xanthine oxidase inhibitor allopurinol enhanced ACh (maximum: 90 +/- 2 and 93 +/- 2%, respectively)- and histamine (maximum: 30 +/- 7 and 37 +/- 8%, respectively)-induced dilations in HFD arterioles, whereas the NAD(P)H oxidase inhibitor apocynin had no significant effect. Correspondingly, in carotid arteries of HFD rats, an enhanced superoxide production was shown by lucigenin-enhanced chemiluminescence, in association with an increased xanthine oxidase, but not NAD(P)H oxidase activity. In addition, a marked xanthine oxidase immunostaining was detected in the endothelial layer of the gracilis arterioles of HFD, but not in control rats. These findings suggest that, in obese rats, NO mediation of endothelium-dependent dilation of skeletal muscle arterioles is reduced because of an enhanced xanthine oxidase-derived superoxide production. These alterations demonstrate substantial dysregulation of arteriolar tone by the endothelium in HFD-induced obesity, which may contribute to

  4. Characterizing destructive quantum interference in electron transport

    Science.gov (United States)

    Sam-ang, Panu; Reuter, Matthew G.

    2017-05-01

    Destructive quantum interference in electron transport through molecules provides an unconventional route for suppressing electric current. In this work we introduce ‘interference vectors’ for each interference and use them to characterize the interference. An interference vector may be a combination of multiple molecular orbitals (MOs), leading to more robust interference that is likelier to be experimentally observable. In contrast, an interference vector may itself be a MO, in which case the interference is not robust and will be harder to detect. Our characterization scheme quantifies these two possibilities through the degree of rotation and also assigns an order to each interference that describes the shape of the Landauer-Büttiker transmission function around the interference. Several examples are then presented, showcasing the generality of our theory and characterization scheme, which is not limited to specific classes of molecules or particular molecule-electrode coupling patterns.

  5. Interference in ballistic motor learning - is motor interference really sensory?

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards. We hypothesised that interference requires the same circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects...

  6. Quantum Eraser for Three-Slit Interference

    OpenAIRE

    Shah, Naveed Ahmad; Qureshi, Tabish

    2016-01-01

    It is well known that in a two-slit interference experiment, if the information, on which of the two paths the particle followed, is stored in a quantum path detector, the interference is destroyed. However, in a setup where this path information is "erased", the interference can reappear. Such a setup is known as a quantum eraser. A generalization of quantum eraser to a three-slit interference is theoretically analyzed. It is shown that three complementary interference patterns can arise out...

  7. estimations of cholesterol, triglycerides and fractionation

    African Journals Online (AJOL)

    Preferred Customer

    . 2Department of Science Laboratory .... clinical-chemistry parameters directly from whole blood, plasma or serum. The direct use of ..... Research suggests that men with high cholesterol levels when they are young. (mean age of 22 years) ...

  8. [Cholesterol and atherosclerosis. Historical considerations and treatment].

    Science.gov (United States)

    Zárate, Arturo; Manuel-Apolinar, Leticia; Basurto, Lourdes; De la Chesnaye, Elsa; Saldívar, Iván

    2016-01-01

    Cholesterol is a precursor of steroid hormones and an essential component of the cell membrane, however, altered regulation of the synthesis, absorption and excretion of cholesterol predispose to cardiovascular diseases of atherosclerotic origin. Despite, the recognition of historical events for 200 years, starting with Michel Chevreul naming «cholesterol»; later on, Lobstein coining the term atherosclerosis and Marchand introducing it, Anichkov identifying cholesterol in atheromatous plaque, and Brown and Goldstein discovering LDL receptor; as well as the emerging of different drugs, such as fibrates, statins and cetrapibs this decade, promising to increase HDL and the most recent ezetimibe and anti-PCSK9 to inhibit the degradation of LDL receptor, however morbidity has not been reduced in cardiovascular disease. Copyright © 2016. Published by Masson Doyma México S.A.

  9. What Are High Blood Cholesterol and Triglycerides?

    Science.gov (United States)

    ... in your blood. How can I control my cholesterol? • Cut down on foods high in saturated and trans fats. These include fatty meats, organ meats such as liver, shellfish, cheese, whole-milk dairy products, and solid fats such ...

  10. Proximate composition and cholesterol concentrations of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-18

    DWB) for raw and fried samples, respectively, but decreased to 295.20 ... Key words: Rhynchophorus phoenicis, Oryctes monoceros, proximate composition, cholesterol, heat treatment. INTRODUCTION. Insects have played ...

  11. Wheat alkylresorcinols reduce micellar solubility of cholesterol in vitro and increase cholesterol excretion in mice.

    Science.gov (United States)

    Horikawa, Kazumasa; Hashimoto, Chiaki; Kikuchi, Yosuke; Makita, Miki; Fukudome, Shin-Ichi; Okita, Kimiko; Wada, Naoyuki; Oishi, Katsutaka

    2017-03-01

    Epidemiological studies have shown that the consumption of whole grains can reduce risk for metabolic disorders. We recently showed that chronic supplementation with wheat alkylresorcinols (ARs) prevents glucose intolerance and insulin resistance with hepatic lipid accumulation induced in mice by a high-fat high-sucrose diet (HFHSD). This study examines the effects of ARs on the micellar solubility of cholesterol in vitro, as well as the effects of transient AR supplementation on faecal lipid excretion and plasma lipid levels in mice. We found that ARs formed bile micelles with taurocholate independently of phospholipids, and dose-dependently decreased the micellar solubility of cholesterol in a biliary micelle model. Transient AR supplementation with HFHSD increased faecal cholesterol and triglyceride contents and decreased plasma cholesterol concentrations. These suggest that one underlying mechanism through which ARs suppress diet-induced obesity is by interfering with the micellar cholesterol solubilisation in the digestive tract, which subsequently decreases cholesterol absorption.

  12. SNAREs and cholesterol movement for steroidogenesis.

    Science.gov (United States)

    Kraemer, Fredric B; Shen, Wen-Jun; Azhar, Salman

    2017-02-05

    Steroidogenesis is a complex process through which cholesterol traffics to mitochondria and is converted via a series of enzymatic steps to steroid hormones. Although the rate-limiting step in this process is the movement of cholesterol from the outer to the inner mitochondrial membrane via the actions of StAR, a continuous supply of cholesterol must be delivered to the outer mitochondrial membrane during active steroidogenesis and this is derived from multiple sources, including lipoprotein uptake, endogenous cholesterol synthesis and release from stores within cytoplasmic lipid droplets. A number of mechanisms have been suggested to contribute to cholesterol trafficking to mitochondria; however, there is no definitive consensus and this is particularly so in regards to trafficking from cytoplasmic lipid droplets. In this paper we review experiments in which we have surveyed the expression of SNARE proteins in steroidogenic tissue and cells and examined the role of SNAREs in mediating cholesterol movement from lipid droplets to the mitochondria based on multiple studies that identified SNAREs as components of cytoplasmic lipid droplets. We established and characterized an in vitro mitochondria reconstitution assay system that enabled us to examine the impact of adding recombinant SNARE proteins specifically on the movement of cholesterol from model lipid droplets to the outer mitochondrial membrane. Using this reconstitution assay system in combination with siRNA knockdown experiments in rat primary granulosa cells or in steroidogenic cell lines, we showed that several SNARE proteins are important components in the trafficking of cholesterol from lipid droplets to the mitochondria for steroidogenesis. Published by Elsevier B.V.

  13. Assessing possible hazards of reducing serum cholesterol.

    Science.gov (United States)

    Law, M R; Thompson, S G; Wald, N J

    1994-02-05

    To assess whether low serum cholesterol concentration increases mortality from any cause. Systematic review of published data on mortality from causes other than ischaemic heart disease derived from the 10 largest cohort studies, two international studies, and 28 randomised trials, supplemented by unpublished data on causes of death obtained when necessary. Excess cause specific mortality associated with low or lowered serum cholesterol concentration. The only cause of death attributable to low serum cholesterol concentration was haemorrhagic stroke. The excess risk was associated only with concentrations below about 5 mmol/l (relative risk 1.9, 95% confidence interval 1.4 to 2.5), affecting about 6% of people in Western populations. For noncirculatory causes of death there was a pronounced difference between cohort studies of employed men, likely to be healthy at recruitment, and cohort studies of subjects in community settings, necessarily including some with existing disease. The employed cohorts showed no excess mortality. The community cohorts showed associations between low cholesterol concentration and lung cancer, haemopoietic cancers, suicide, chronic bronchitis, and chronic liver and bowel disease; these were most satisfactorily explained by early disease or by factors that cause the disease lowering serum cholesterol concentration (depression causes suicide and lowers cholesterol concentration, for example). In the randomised trials nine deaths (from a total of 687 deaths not due to ischaemic heart disease in treated subjects) were attributed to known adverse effects of the specific treatments, but otherwise there was no evidence of an increased mortality from any cause arising from reduction in cholesterol concentration. There is no evidence that low or reduced serum cholesterol concentration increases mortality from any cause other than haemorrhagic stroke. This risk affects only those people with a very low concentration and even in these will be

  14. Biodynamics of cholesterol and bile acids in the lithiasic hamster.

    Science.gov (United States)

    Khallou, J; Riottot, M; Parquet, M; Verneau, C; Lutton, C

    1991-11-01

    By using the isotopic equilibrium method in the young male Syrian hamster, the rates of cholesterol turnover processes, i.e. dietary cholesterol absorption, cholesterol synthesis, cholesterol excretion in the faeces and urine and cholesterol transformation into bile acids, were determined in the hamster receiving a control (C) or a lithogenic diet (L) for 7 weeks. At the end of this period the gall bladder of all animals in group L contained cholesterol gallstones. The coefficient of dietary cholesterol absorption was reduced by 26%, cholesterol synthesis and cholesterol faecal excretion were twofold higher in group L than in group C. Bile acid content in the small intestine was diminished in group L, but bile acid composition was similar in the two groups. The increase in cholesterogenesis in lithiasic animals essentially took place in the liver. Bile acid biosynthesis did not significantly differ in the two groups, but represented only 35% of total cholesterol input (dietary absorption + internal secretion) in group L v. 52% in group C. Thus, in the lithiasic hamster, hepatic synthesis of cholesterol and bile acids are not coupled. The molar percentage of cholesterol in bile was twofold higher in group L than in group C but those of bile acids and of phospholipids were not modified. In the lithiasic hamster the specific activity of biliary cholesterol was similar to that in plasma and liver. Consequently, biliary cholesterol does not derive directly from cholesterol newly synthesized in the liver but from hepatic cholesterol rapidly exchangeable with plasma cholesterol.

  15. Evaluation of LDL-Cholesterol / HDL-Cholesterol Ratio as Predictor of Dyslipidemia in Subclinical Hypothyroidism

    Directory of Open Access Journals (Sweden)

    Smita S. Kottagi

    2014-01-01

    Full Text Available Background: Subclinical hypothyroidism is defined as a serum TSH concentration above the upper limit of the reference range when serum T3 and T4 concentrations are within reference ranges. Subclinical thyroid disease is a laboratory diagnosis. Patients with subclinical disease have few or no definitive clinical signs or symptoms of thyroid dysfunction. It has been associated with higher levels of some cardiovascular risk factors. Despite some conflicting results, many studies have found that subjects with subclinical hypothyroidism have total cholesterol and low density lipoprotein cholesterol levels higher than euthyroid subjects. The association between subclinical hypothyroidism and dyslipidemia is well known. Aims and Objectives: This study is an attempt to find the importance of Low Density Lipoprotein – Cholesterol / Higher Density Lipoprotein - Cholesterol (LDL-C/HDL-C ratio rather than measurement of individual lipid profile parameters in bringing to light the dyslipidemic state associated with subclinical hypothyroidism. Materials and Methods: We studied 30 subclinical hypothyroid cases with age above 35 yrs and 30 age matched euthyroid controls. Serum T3, T4, TSH were estimated by ELISA method, serum total cholesterol, HDL Cholesterol by enzymatic CHOD-PAP method, and LDL cholesterol using Friedewald formula. Results: We found the significant increase in the serum levels of TSH (p < 0.001, Total cholesterol (p<0.001, LDL cholesterol (p<0.001, and LDL-C/HDL-C (p<0.001, Systolic blood pressure and diastolic blood pressure (p<0.001. There was no significant change in the levels of serum T3, T4, HDL- cholesterol. Conclusion: Increased levels of total cholesterol, LDL cholesterol and increased LDL-C/HDL-C ratio are seen in patients with subclinical hypothyroidism. LDL-C/HDLC ratio is a better indicator for dyslipidemia in subclinical hypothyroid cases.

  16. Dietary cholesterol modulates pathogen blocking by Wolbachia.

    Directory of Open Access Journals (Sweden)

    Eric P Caragata

    Full Text Available The bacterial endosymbiont Wolbachia pipientis protects its hosts from a range of pathogens by limiting their ability to form infections inside the insect. This "pathogen blocking" could be explained by innate immune priming by the symbiont, competition for host-derived resources between pathogens and Wolbachia, or the direct modification of the cell or cellular environment by Wolbachia. Recent comparative work in Drosophila and the mosquito Aedes aegypti has shown that an immune response is not required for pathogen blocking, implying that there must be an additional component to the mechanism. Here we have examined the involvement of cholesterol in pathogen blocking using a system of dietary manipulation in Drosophila melanogaster in combination with challenge by Drosophila C virus (DCV, a common fly pathogen. We observed that flies reared on cholesterol-enriched diets infected with the Wolbachia strains wMelPop and wMelCS exhibited reduced pathogen blocking, with viral-induced mortality occurring 2-5 days earlier than flies reared on Standard diet. This shift toward greater virulence in the presence of cholesterol also corresponded to higher viral copy numbers in the host. Interestingly, an increase in dietary cholesterol did not have an effect on Wolbachia density except in one case, but this did not directly affect the strength of pathogen blocking. Our results indicate that host cholesterol levels are involved with the ability of Wolbachia-infected flies to resist DCV infections, suggesting that cholesterol contributes to the underlying mechanism of pathogen blocking.

  17. Cholesterol suppresses antimicrobial effect of statins

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Haeri

    2015-12-01

    Full Text Available Objective(s:Isoprenoid biosynthesis is a key metabolic pathway to produce a wide variety of biomolecules such as cholesterol and carotenoids, which target cell membranes. On the other hand, it has been reported that statins known as inhibitors of isoprenoid biosynthesis and cholesterol lowering agents, may have a direct antimicrobial effect on the some bacteria. The exact action of statins in microbial metabolism is not clearly understood. It is possible that statins inhibit synthesis or utilization of some sterol precursor necessary for bacterial membrane integrity. Accordingly, this study was designed in order to examine if statins inhibit the production of a compound, which can be used in the membrane, and whether cholesterol would replace it and rescue bacteria from toxic effects of statins. Materials and Methods: To examine the possibility we assessed antibacterial effect of statins with different classes; lovastatin, simvastatin, and atorvastatin, alone and in combination with cholesterol on two Gram-positive (Staphylococcus aureus and Enterococcus faecalis and two Gram-negative (Pseudomonas aeruginosa and Escherichia coli bacteria using gel diffusion assay. Results: Our results showed that all of the statins except for lovastatin had significant antibacterial property in S. aureus, E. coli, and Enter. faecalis. Surprisingly, cholesterol nullified the antimicrobial action of effective statins in statin-sensitive bacteria. Conclusion: It is concluded that statins may deprive bacteria from a metabolite responsible for membrane stability, which is effectively substituted by cholesterol.

  18. Methotrexate in Atherogenesis and Cholesterol Metabolism

    Directory of Open Access Journals (Sweden)

    Eric Coomes

    2011-01-01

    Full Text Available Methotrexate is a disease-modifying antirheumatic drug commonly used to treat inflammatory conditions such as rheumatoid arthritis which itself is linked to increased cardiovascular risk. Treatments that target inflammation may also impact the cardiovascular system. While methotrexate improves cardiovascular risk, inhibition of the cyclooxygenase (COX-2 enzyme promotes atherosclerosis. These opposing cardiovascular influences may arise from differing effects on the expression of proteins involved in cholesterol homeostasis. These proteins, ATP-binding cassette transporter (ABC A1 and cholesterol 27-hydroxylase, facilitate cellular cholesterol efflux and defend against cholesterol overload. Methotrexate upregulates expression of cholesterol 27-hydroxylase and ABCA1 via adenosine release, while COX-2 inhibition downregulates these proteins. Adenosine, acting through the A2A and A3 receptors, may upregulate proteins involved in reverse cholesterol transport by cAMP-PKA-CREB activation and STAT inhibition, respectively. Elucidating underlying cardiovascular mechanisms of these drugs provides a framework for developing novel cardioprotective anti-inflammatory medications, such as selective A2A receptor agonists.

  19. Targeting cholesterol-rich microdomains to circumvent tamoxifen-resistant breast cancer

    Science.gov (United States)

    2011-01-01

    Introduction Adjuvant treatment with tamoxifen substantially improves survival of women with estrogen-receptor positive (ER+) tumors. Tamoxifen resistance (TAMR) limits clinical benefit. RRR-α-tocopherol ether-linked acetic acid analogue (α-TEA) is a small bioactive lipid with potent anticancer activity. We evaluated the ability of α-TEA in the presence of tamoxifen to circumvent TAMR in human breast cancer cell lines. Methods Two genotypically matched sets of TAM-sensitive (TAMS) and TAM-resistant (TAMR) human breast cancer cell lines were assessed for signal-transduction events with Western blotting, apoptosis induction with Annexin V-FITC/PI assays, and characterization of cholesterol-rich microdomains with fluorescence staining. Critical involvement of selected mediators was determined by using RNA interference and chemical inhibitors. Results Growth-factor receptors (total and phosphorylated forms of HER-1 and HER-2), their downstream prosurvival mediators pAkt, pmTOR, and pERK1/2, phosphorylated form of estrogen receptor-α (pER-α at Ser-167 and Ser-118, and cholesterol-rich lipid microdomains were highly amplified in TAMR cell lines and enhanced by treatment with TAM. α-TEA disrupted cholesterol-rich microdomains, acted cooperatively with TAM to reduce prosurvival mediators, and induced DR5-mediated mitochondria-dependent apoptosis via an endoplasmic reticulum stress-triggered pro-death pJNK/CHOP/DR5 amplification loop. Furthermore, methyl-β-cyclodextrin (MβCD), a chemical disruptor of cholesterol rich microdomains, acted cooperatively with TAM to reduce prosurvival mediators and to induce apoptosis. Conclusions Data for the first time document that targeting cholesterol-rich lipid microdomains is a potential strategy to circumvent TAMR, and the combination of α-TEA + TAM can circumvent TAMR by suppression of prosurvival signaling via disruption of cholesterol-rich lipid microdomains and activation of apoptotic pathways via induction of endoplasmic

  20. Ezetimibe-sensitive cholesterol uptake by NPC1L1 protein does not require endocytosis.

    Science.gov (United States)

    Johnson, Tory A; Pfeffer, Suzanne R

    2016-06-01

    Human NPC1L1 protein mediates cholesterol absorption in the intestine and liver and is the target of the drug ezetimibe, which is used to treat hypercholesterolemia. Previous studies concluded that NPC1L1-GFP protein trafficking is regulated by cholesterol binding and that ezetimibe blocks NPC1L1-GFP function by inhibiting its endocytosis. We used cell surface biotinylation to monitor NPC1L1-GFP endocytosis and show that ezetimibe does not alter the rate of NPC1L1-GFP endocytosis in cultured rat hepatocytes grown under normal growth conditions. As expected, NPC1L1-GFP endocytosis depends in part on C-terminal, cytoplasmically oriented sequences, but endocytosis does not require cholesterol binding to NPC1L1's N-terminal domain. In addition, two small- molecule inhibitors of general (and NPC1L1-GFP) endocytosis failed to inhibit the ezetimibe-sensitive uptake of [(3)H]cholesterol from taurocholate micelles. These experiments demonstrate that cholesterol uptake by NPC1L1 does not require endocytosis; moreover, ezetimibe interferes with NPC1L1's cholesterol adsorption activity without blocking NPC1L1 internalization in RH7777 cells. © 2016 Johnson and Pfeffer. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  1. Planar Amperometric Glucose Sensor Based on Glucose Oxidase Immobilized by Chitosan Film on Prussian Blue Layer

    Directory of Open Access Journals (Sweden)

    Zongyou Chen

    2002-04-01

    Full Text Available A planar amperometric glucose microsensor based on glucose oxidase immobilized by chitosan film on Prussian Blue layer has been developed. The experimental results show that the optimum detection potential is 50 mV (versus Ag/AgCl and the optimum pH is 6.5. Under the selective conditions the sensor exhibits excellent sensitivity of 98 nA/M and a linear range of 0.1-6.0 mM. The apparent Michanelis-Menten constant of the sensor is 21 mM. The response time is less than 60 seconds. No apparent change in the response to glucose was observed during one month. Foremost, the interference of ascorbic and uric acids can be avoided due to selective permeability of chitosan film and electrocatalysis of PB layer to H2O2. The sensor has been applied to detect glucose in human blood serum.

  2. Structural and Functional Association of Trypanosoma brucei MIX Protein with Cytochrome c Oxidase Complex ▿ †

    Science.gov (United States)

    Zíková, Alena; Panigrahi, Aswini K.; Uboldi, Alessandro D.; Dalley, Rachel A.; Handman, Emanuela; Stuart, Kenneth

    2008-01-01

    A mitochondrial inner membrane protein, designated MIX, seems to be essential for cell viability. The deletion of both alleles was not possible, and the deletion of a single allele led to a loss of virulence and aberrant mitochondrial segregation and cell division in Leishmania major. However, the mechanism by which MIX exerts its effect has not been determined. We show here that MIX is also expressed in the mitochondrion of Trypanosoma brucei, and using RNA interference, we found that its loss leads to a phenotype that is similar to that described for Leishmania. The loss of MIX also had a major effect on cytochrome c oxidase activity, on the mitochondrial membrane potential, and on the production of mitochondrial ATP by oxidative phosphorylation. Using a tandem affinity purification tag, we found that MIX is associated with a multiprotein complex that contains subunits of the mitochondrial cytochrome c oxidase complex (respiratory complex IV), the composition of which was characterized in detail. The specific function of MIX is unknown, but it appears to be important for the function of complex IV and for mitochondrial segregation and cell division in T. brucei. PMID:18776036

  3. Dietary cholesterol impairs memory and memory increases brain cholesterol and sulfatide levels.

    Science.gov (United States)

    Darwish, Deya S; Wang, Desheng; Konat, Gregory W; Schreurs, Bernard G

    2010-02-01

    Cholesterol and sulfatides play many important roles in learning and memory. To date, our observations about the effects of cholesterol on learning have been assessed during response acquisition; that is, the learning of a new memory. Here, we report for the first time to our knowledge, on the effect of a cholesterol diet on a previously formed memory. Rabbits were given trace conditioning of the nictitating membrane response for 10 days, then fed a 2% cholesterol diet for 8 weeks, and then assessed for memory recall of the initially learned task. We show that dietary cholesterol had an adverse effect on memory recall. Second, we investigated whether dietary cholesterol caused an increase in brain cholesterol and sulfatide levels in four major brain structures (hippocampus, frontal lobe, brainstem, and cerebellum) using a technique for analyzing myelin and myelin-free fractions separately. Although our data confirm previous findings that dietary cholesterol does not directly affect cholesterol and establish that it does not affect sulfatide levels in the brain, these levels did increase rather significantly in the hippocampus and frontal lobe as a function of learning and memory. (c) 2009 APA, all rights reserved.

  4. Cholesterol aided etching of tomatine gold nanoparticles: a non-enzymatic blood cholesterol monitor.

    Science.gov (United States)

    Raj, Vidya; Johnson, Teslin; Joseph, Kuruvilla

    2014-10-15

    Colloidal gold is extensively used for molecular sensing because of the wide flexibilities it offers in terms of modifications of the gold nanoparticles (GNPs) surface with a variety of functional groups. We describe a simple, enzyme free assay for the detection of cholesterol, and demonstrate its applicability by estimating cholesterol in human serum samples. To enable cholesterol detection, we functionalized GNPs with tomatine, a glycoalkaloid found in the leaves and stem of tomato plants. The binding of cholesterol onto tomatine functionalized gold nanoparticles (TGNPs) was characterized by a blue shift in the plasmon absorption spectra (SPR) followed by reduction in the particle size. The TGNPs have been core etched with increasing concentration of cholesterol and with 800 ng/mL of cholesterol particles in the size range of 10-12 nm have been obtained. This behavior was attributed to the enhanced hydrophobicity of the surface acquired by cholesterol binding resulting in the folding or shrinkage of molecule in turn leading to core etching. The method was successfully applied for the detection of cholesterol in real samples and agrees well with values obtained from the conventional method. Because of its significant plasmonic shift and simplicity, this biosensor could be used for cholesterol detection as it does not demand either any hazardous and costly chemicals or any complex synthetic routes. Copyright © 2014. Published by Elsevier B.V.

  5. Interference and memory capacity limitations.

    Science.gov (United States)

    Endress, Ansgar D; Szabó, Szilárd

    2017-10-01

    Working memory (WM) is thought to have a fixed and limited capacity. However, the origins of these capacity limitations are debated, and generally attributed to active, attentional processes. Here, we show that the existence of interference among items in memory mathematically guarantees fixed and limited capacity limits under very general conditions, irrespective of any processing assumptions. Assuming that interference (a) increases with the number of interfering items and (b) brings memory performance to chance levels for large numbers of interfering items, capacity limits are a simple function of the relative influence of memorization and interference. In contrast, we show that time-based memory limitations do not lead to fixed memory capacity limitations that are independent of the timing properties of an experiment. We show that interference can mimic both slot-like and continuous resource-like memory limitations, suggesting that these types of memory performance might not be as different as commonly believed. We speculate that slot-like WM limitations might arise from crowding-like phenomena in memory when participants have to retrieve items. Further, based on earlier research on parallel attention and enumeration, we suggest that crowding-like phenomena might be a common reason for the 3 major cognitive capacity limitations. As suggested by Miller (1956) and Cowan (2001), these capacity limitations might arise because of a common reason, even though they likely rely on distinct processes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  6. Interference due to coherence swapping

    Indian Academy of Sciences (India)

    In quantum interference (first order) the important requirement is the coherence of a quantum state, which usually we tend to associate with a particle if it has come from a single source and made to pass through a double slit or through a suit- able device such as a beam splitter (as in a Mach–Zehnder interferometer).

  7. "Quantum Interference with Slits" Revisited

    Science.gov (United States)

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his…

  8. The Interference of Polarised Light

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 4. The Interference of Polarised Light - The Pancharatnam Phase. Rajaram Nityananda. General Article Volume 18 Issue 4 April 2013 pp 309-322. Fulltext. Click here to view fulltext PDF. Permanent link:

  9. Conducted interference on smart meters

    NARCIS (Netherlands)

    Keyer, Cornelis H.A.; Leferink, Frank

    2017-01-01

    The increasing conducted interference caused by modern electronic equipment is causing more problems for electronic, or static, energy meters. These meters are called smart meters when equipped with a communication link, and are replacing the conventional electromechanical meters. It is known that

  10. Interference in Cellular Satellite Systems

    OpenAIRE

    Kilic, Ozlem; Zaghloul, Amir I.

    2010-01-01

    Co-channel beam interference in multi-beam satellite communications systems was investigated particularly for the downlink. Concept of frequency reuse was explained and the role of satellite antenna size and pattern was examined. Conventional spot beam coverage and its impact on determining the antenna size on board was discussed.

  11. In situ synthesis of cylindrical spongy polypyrrole doped protonated graphitic carbon nitride for cholesterol sensing application.

    Science.gov (United States)

    Shrestha, Bishnu Kumar; Ahmad, Rafiq; Shrestha, Sita; Park, Chan Hee; Kim, Cheol Sang

    2017-08-15

    Herein, we demonstrate the exfoliation of bulk graphitic carbon nitrides (g-C 3 N 4 ) into ultra-thin (~3.4nm) two-dimensional (2D) nanosheets and their functionalization with proton (g-C 3 N 4 H + ). The layered semiconductor g-C 3 N 4 H + nanosheets were doped with cylindrical spongy shaped polypyrrole (CSPPy-g-C 3 N 4 H + ) using chemical polymerization method. The as-prepared nanohybrid composite was utilized to fabricate cholesterol biosensors after immobilization of cholesterol oxidase (ChOx) at physiological pH. Large specific surface area and positive charge nature of CSPPy-g-C 3 N 4 H + composite has tendency to generate strong electrostatic attraction with negatively charged ChOx, and as a result they formed stable bionanohybrid composite with high enzyme loading. A detailed electrochemical characterization of as-fabricated biosensor electrode (ChOx-CSPPy-g-C 3 N 4 H + /GCE) exhibited high-sensitivity (645.7 µAmM -1 cm -2 ) in wide-linear range of 0.02-5.0mM, low detection limit (8.0μM), fast response time (~3s), long-term stability, and good selectivity during cholesterol detection. To the best of our knowledge, this novel nanocomposite was utilized for the first time for cholesterol biosensor fabrication that resulted in high sensing performance. Hence, this approach opens a new prospective to utilize CSPPy-g-C 3 N 4 H + composite as cost-effective, biocompatible, eco-friendly, and superior electrocatalytic as well as electroconductive having great application potentials that could pave the ways to explore many other new sensors fabrication and biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Visualization of monoamine oxidase in human brain

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J.S.; Volkow, N.D.; Wang, G.J.; Pappas, N.; Shea, C.; MacGregor, R.R.; Logan, J.

    1996-12-31

    Monoamine oxidase is a flavin enzyme which exists in two subtypes, MAO A and MAO B. In human brain MAO B predominates and is largely compartmentalized in cell bodies of serotonergic neurons and glia. Regional distribution of MAO B was determined by positron computed tomography with volunteers after the administration of deuterium substituted [11C]L-deprenyl. The basal ganglia and thalamus exhibited the greatest concentrations of MAO B with intermediate levels in the frontal cortex and cingulate gyrus while lowest levels were observed in the parietal and temporal cortices and cerebellum. We observed that brain MAO B increases with are in health normal subjects, however the increases were generally smaller than those revealed with post-mortem studies.

  13. Glucose oxidase immobilization onto carbon nanotube networking

    CERN Document Server

    Karachevtsev, V A; Zarudnev, E S; Karachevtsev, M V; Leontiev, V S; Linnik, A S; Lytvyn, O S; Plokhotnichenko, A M; Stepanian, S G

    2012-01-01

    When elaborating the biosensor based on single-walled carbon nanotubes (SWNTs), it is necessary to solve such an important problem as the immobilization of a target biomolecule on the nanotube surface. In this work, the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube network, which was created by the deposition of nanotubes from their solution in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide ester (PSE) was used to form the molecular interface, the bifunctional molecule of which provides the covalent binding with the enzyme shell, and its other part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a molecular interface leaves out the direct adsorption of the enzyme (in this case, its activity decreases) onto the nanotube surface, and, second, it ensures the enzyme localization near the nanotube. The comparison of the resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the PSE environment evidences the creat...

  14. An ultrafiltration assay for lysyl oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Shackleton, D.R.; Hulmes, D.J. (Univ. of Edinburgh Medical School (England))

    1990-03-01

    A modification of the original microdistillation assay for lysyl oxidase is described in which Amicon C-10 microconcentrators are used to separate, by ultrafiltration, the 3H-labeled products released from a (4,5-3H)-lysine-labeled elastin substrate. Enzyme activity is determined by scintillation counting of the ultrafiltrate, after subtraction of radioactivity released in the presence of beta-aminopropionitrile, a specific inhibitor of the enzyme. Conditions are described which optimize both the sensitivity and the efficient use of substrate. The assay shows linear inhibition of activity in up to 1 M urea; hence, as the enzyme is normally diluted in the assay, samples in 6 M urea can be assayed directly, without prior dialysis, and corrected for partial inhibition. Comparable results are obtained when enzyme activity is assayed by ultrafiltration or microdistillation. The assay is simple and convenient and, by using disposable containers throughout, it eliminates the need for time-consuming decontamination of radioactive glassware.

  15. Characterization of Glucose Oxidase from Penicillium notatum

    Directory of Open Access Journals (Sweden)

    Nabeela Saleem

    2009-01-01

    Full Text Available In the present study glucose oxidase (GOD has been isolated from a culture filtrate of Penicillium notatum. The enzyme was purified by ammonium sulphate precipitation, diethylaminoethyl (DEAE cellulose ion-exchange chromatography and Sephadex gel filtration. This protocol gave 16.47-fold purification and 25 % recovery of the enzyme. The optimum pH and temperature for the activity were 5.4 and 45 °C, respectively. The Km and vmax values for the enzyme were 10.5 mM and 456 U/mg, respectively. A detailed kinetic study of thermal inactivation was carried out. Both enthalpy of activation (ΔH* and entropy of activation (ΔS* decreased at higher temperatures. Moreover, free energy of denaturation (ΔG* increased at higher temperature, making the enzyme thermally stable. A possible explanation for the thermal inactivation of GOD at higher temperatures is also discussed.

  16. Dairy products and plasma cholesterol levels

    Directory of Open Access Journals (Sweden)

    Lena Ohlsson

    2010-08-01

    Full Text Available Cholesterol synthesized in the body or ingested is an essential lipid component for human survival from our earliest life. Newborns ingest about 3–4 times the amount per body weight through mother's milk compared to the dietary intake of adults. A birth level of 1.7 mmol/L plasma total cholesterol will increase to 4–4.5 mmol/L during the nursing period and continue to increase from adulthood around 40% throughout life. Coronary artery disease and other metabolic disorders are strongly associated with low-density lipoprotein (LDL and high-density lipoprotein (HDL cholesterol as well as triacylglycerol concentration. Milk fat contains a broad range of fatty acids and some have a negative impact on the cholesterol rich lipoproteins. The saturated fatty acids (SFAs, such as palmitic acid (C16:0, myristic acid (C14:0, and lauric acid (C12:0, increase total plasma cholesterol, especially LDL, and constitute 11.3 g/L of bovine milk, which is 44.8% of total fatty acid in milk fat. Replacement of dairy SFA and trans-fatty acids with polyunsaturated fatty acids decreases plasma cholesterol, especially LDL cholesterol, and is associated with a reduced risk of cardiovascular disease. Available data shows different effects on lipoproteins for different dairy products and there is uncertainty as to the impact a reasonable intake amount of dairy items has on cardiovascular risk. The aim of this review is to elucidate the effect of milk components and dairy products on total cholesterol, LDL, HDL, and the LDL/HDL quotients. Based on eight recent randomized controlled trials of parallel or cross-over design and recent reviews it can be concluded that replacement of saturated fat mainly (but not exclusively derived from high-fat dairy products with low-fat dairy products lowers LDL/HDL cholesterol and total/HDL cholesterol ratios. Whey, dairy fractions enriched in polar lipids, and techniques such as fermentation, or fortification of cows feeding can be used

  17. Inhibition of rat mammary tumorigenesis by dietary cholesterol.

    Science.gov (United States)

    el-Sohemy, A; Bruce, W R; Archer, M C

    1996-01-01

    The effects of dietary cholesterol and oxidized cholesterol on mammary tumor development were examined in female Sprague-Dawley rats exposed to the carcinogen N-methyl-N-nitrosourea (MNU). Animals were administered 50 mg/kg MNU at 50 days of age and fed either a control (AIN-76) diet or the control diet supplemented with 0.3% cholesterol or 0.3% oxidized cholesterol for up to 26 weeks. The oxidized cholesterol was prepared by heating cholesterol at 110 degrees C for 48 h. Gas chromatographic analysis of the oxidized cholesterol revealed a 2% yield of oxidation products in addition to a large amount of unchanged cholesterol (> 96%). Tumor incidence in the cholesterol group (67%) was significantly lower than in the control group (96%, P < 0.05), but the oxidized cholesterol group (79%) was not significantly different from the control or cholesterol groups. Average number of tumors per animal was lower in the cholesterol group (1.5) than in the control (2.8) or oxidized cholesterol groups (2.3, P < 0.005). Serum low density lipoprotein (LDL) cholesterol was greater in the cholesterol (185 +/- 38 mg/dl) and the oxidized cholesterol groups (160 +/- 34 mg/dl) than in the controls (55 +/- 4 mg/dl, P < 0.05), although there was no difference between the cholesterol and the oxidized cholesterol groups. These results show that dietary cholesterol inhibits mammary tumor development in this model. Elevated serum LDL cholesterol may inhibit de novo cholesterol synthesis in preneoplastic and/or tumor cells, thereby inhibiting their proliferation.

  18. The usefulness of total cholesterol and high density lipoprotein ...

    African Journals Online (AJOL)

    Objective: To determine the usefulness of total cholesterol/high-density lipoprotein cholesterol and/or highdensity lipoprotein cholesterol/total cholesterol ratios in the interpretation of lipid profile result in clinical practice. Methods: This is a prospective case-control study involving 109 diabetics, 98 diabetic hypertensives, 102 ...

  19. Cholesterol granuloma of the breast: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Eun; Park, In Seo; Lee, Kyung Hee; Kim, Mi Young; Kim, Youn Jeong [College of Medicine, Inha University, Incheon (Korea, Republic of)

    2008-06-15

    Cholesterol granuloma is histologically characterized as fibrous granulation tissue containing cholesterol crystals within surrounding giant cells. Cases of cholesterol granuloma of the breast are rare. In fact, only eight cases have been previously described, and of these, an ultrasonography was performed in only. Here, we report the ultrasonographic findings of a breast cholesterol granuloma accompanied with a literature review.

  20. Dietary cholesterol - the role of eggs in the prudent diet

    African Journals Online (AJOL)

    eggs from the diet should be weighed against the effect of deprivation of these nutrients. Dietary cholesterol, serum cholesterol and CHD. Metabolic ward and controlled studies have demonstrated that an increase in dietary cholesterol as the only dietary variable, taken either as crystalline cholesterol, egg yolk or whole egg ...

  1. Cholesterol-Lowering Therapy Interventions: A Pharmacoeconomic Assessment

    OpenAIRE

    Michael A. Kortt; Armstrong, Edward P.

    1998-01-01

    Elevated cholesterol levels are associated with an increased risk of cardiovascular diseases. Treatment strategies promoting the associated health benefits from a reduction in elevated cholesterol levels have been outlined in guidelines published by the National Cholesterol Education Program. Clinicians and researchers have also examined the economic benefits associated with reducing elevated cholesterol levels. Most of these studies have employed traditional pharmacoeconomic techniques like ...

  2. Cholesterol and ocular pathologies: focus on the role of cholesterol-24S-hydroxylase in cholesterol homeostasis

    Directory of Open Access Journals (Sweden)

    Fourgeux Cynthia

    2015-03-01

    Full Text Available The retina is responsible for coding the light stimulus into a nervous signal that is transferred to the brain via the optic nerve. The retina is formed by the association of the neurosensory retina and the retinal pigment epithelium that is supported by Bruch’s membrane. Both the physical and metabolic associations between these partners are crucial for the functioning of the retina, by means of nutrient intake and removal of the cell and metabolic debris from the retina. Dysequilibrium are involved in the aging processes and pathologies such as age-related macular degeneration, the leading cause of visual loss after the age of 50 years in Western countries. The retina is composed of several populations of cells including glia that is involved in cholesterol biosynthesis. Cholesterol is the main sterol in the retina. It is present as free form in cells and as esters in Bruch’s membrane. Accumulation of cholesteryl esters has been associated with aging of the retina and impairment of the retinal function. Under dietary influence and in situ synthesized, the metabolism of cholesterol is regulated by cell interactions, including neurons and glia via cholesterol-24S-hydroxylase. Several pathophysiological associations with cholesterol and its metabolism can be suggested, especially in relation to glaucoma and age-related macular degeneration.

  3. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes

    Science.gov (United States)

    Storey, Stephen M.; McIntosh, Avery L.; Huang, Huan; Landrock, Kerstin K.; Martin, Gregory G.; Landrock, Danilo; Payne, H. Ross; Atshaves, Barbara P.; Kier, Ann B.

    2012-01-01

    A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2/SCP-x/L-FABP null mice and hepatocytes. Taken together

  4. Aronia melanocarpa (chokeberry) polyphenol-rich extract improves antioxidant function and reduces total plasma cholesterol in apolipoprotein E knockout mice.

    Science.gov (United States)

    Kim, Bohkyung; Ku, Chai Siah; Pham, Tho X; Park, Youngki; Martin, Derek A; Xie, Liyang; Taheri, Rod; Lee, Jiyoung; Bolling, Bradley W

    2013-05-01

    We hypothesized that a polyphenol-rich chokeberry extract (CBE) would modulate hepatic lipid metabolism and improve antioxidant function in apolipoprotein E knockout (apoE(-/-)) mice. ApoE(-/-) mice were fed diets containing 15% fat with 0.2% cholesterol alone or supplemented with 0.005% or 0.05% CBE for 4 weeks. CBE polyphenol content was determined by the total phenols, 4-dimethylaminocinnamaldehyde, and ultra high-performance liquid chromatography-mass spectrometry methods. The 0.05% CBE diet provided mice with mean daily doses of 1.2 mg gallic acid equivalents of total phenols, 0.19 mg anthocyanins, 0.17 mg phenolic acids, 0.06 mg proanthocyanidins (as catechin-equivalents), and 0.02 mg flavonols. The 0.05% CBE group had 12% less plasma total cholesterol concentrations than the control. Despite the hypocholesterolemic effect of CBE, hepatic mRNA levels of low-density lipoprotein receptor, hydroxyl-3-methylglutaryl coenzyme A reductase and cholesterol 7α-hydroxylase in CBE-fed mice were not significantly different from controls. Dietary CBE did not alter hepatic lipid content or the hepatic expression of genes involved in lipogenesis and fatty acid β-oxidation such as fatty acid synthase, carnitine palmitoyltransferase 1 and acyl-CoA oxidase. Plasma paraoxonase and catalase activities were significantly increased in mice fed 0.05% CBE. Both CBE diets increased hepatic glutathione peroxidase (GPx) activity but the 0.05% CBE group had 24% less proximal intestine GPx activity relative to controls. Thus, dietary CBE lowered total cholesterol and improved plasma and hepatic antioxidant function at nutritionally-relevant doses in apoE(-/-) mice. Furthermore, the CBE cholesterol-lowering mechanism in apoE(-/-) mice was independent of hepatic expression of genes involved in cholesterol metabolism. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Evaluation of oxalate decarboxylase and oxalate oxidase for industrial applications.

    Science.gov (United States)

    Cassland, Pierre; Sjöde, Anders; Winestrand, Sandra; Jönsson, Leif J; Nilvebrant, Nils-Olof

    2010-05-01

    Increased recirculation of process water has given rise to problems with formation of calcium oxalate incrusts (scaling) in the pulp and paper industry and in forest biorefineries. The potential in using oxalate decarboxylase from Aspergillus niger for oxalic acid removal in industrial bleaching plant filtrates containing oxalic acid was examined and compared with barley oxalate oxidase. Ten different filtrates from chemical pulping were selected for the evaluation. Oxalate decarboxylase degraded oxalic acid faster than oxalate oxidase in eight of the filtrates, while oxalate oxidase performed better in one filtrate. One of the filtrates inhibited both enzymes. The potential inhibitory effect of selected compounds on the enzymatic activity was tested. Oxalate decarboxylase was more sensitive than oxalate oxidase to hydrogen peroxide. Oxalate decarboxylase was not as sensitive to chlorate and chlorite as oxalate oxidase. Up to 4 mM chlorate ions, the highest concentration tested, had no inhibitory effect on oxalate decarboxylase. Analysis of the filtrates suggests that high concentrations of chlorate present in some of the filtrates were responsible for the higher sensitivity of oxalate oxidase in these filtrates. Oxalate decarboxylase was thus a better choice than oxalate oxidase for treatment of filtrates from chlorine dioxide bleaching.

  6. The Role of Macrophage Lipophagy in Reverse Cholesterol Transport

    Directory of Open Access Journals (Sweden)

    Se-Jin Jeong

    2017-03-01

    Full Text Available Macrophage cholesterol efflux is a central step in reverse cholesterol transport, which helps to maintain cholesterol homeostasis and to reduce atherosclerosis. Lipophagy has recently been identified as a new step in cholesterol ester hydrolysis that regulates cholesterol efflux, since it mobilizes cholesterol from lipid droplets of macrophages via autophagy and lysosomes. In this review, we briefly discuss recent advances regarding the mechanisms of the cholesterol efflux pathway in macrophage foam cells, and present lipophagy as a therapeutic target in the treatment of atherosclerosis.

  7. Lysyl oxidase-like 2 level and glaucoma surgical outcomes.

    Science.gov (United States)

    Park, Hae-Young Lopilly; Kim, Jie Hyun; Park, Chan Kee

    2014-04-24

    To evaluate the levels of TGF-β and lysyl oxidases in both the aqueous humor and in Tenon's tissue in patients with POAG, and to assess their association with bleb morphological features and outcomes of glaucoma surgery. Eighteen POAG patients scheduled to undergo glaucoma surgery and 17 healthy controls were enrolled. At the time of surgery, approximately 0.1 mL aqueous humor through an anterior chamber paracentesis and a 4 × 4-mm sample of Tenon's tissue were obtained. Concentrations of TGF-β and lysyl oxidases (types 1 and 2) were analyzed by ELISA. The bleb morphologic features based on the Moorfields Bleb Grading System were evaluated by bleb photographs. The TGF-β in Tenon's tissue and lysyl oxidase-like 2 in aqueous humor and in Tenon's tissue were significantly elevated in POAG patients. When POAG patients were divided by outcome 1 year after surgery, lysyl oxidase-like 2 protein was significantly higher in both aqueous humor and Tenon's tissue of the failure group. The level of lysyl oxidase-like 2 protein was significantly correlated with that of TGF-β in the Tenon's tissue. Lysyl oxidase-like 2 level in the aqueous humor (r = 0.563, P lysyl oxidase-like 2 levels at the time of surgery were significantly correlated with 1-year outcomes of glaucoma surgery. The level of lysyl oxidase-like 2 was significantly correlated with that of TGF-β, suggesting induction by TGF-β. Modulation of lysyl oxidase-like 2 levels may have important applications in glaucoma surgery. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  8. Direct regulation of cytochrome c oxidase by calcium ions.

    Directory of Open Access Journals (Sweden)

    Tatiana Vygodina

    Full Text Available Cytochrome c oxidase from bovine heart binds Ca(2+ reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+ shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca(2+ on the functional characteristics of cytochrome oxidase was revealed earlier. Here we report that Ca(2+ inhibits cytochrome oxidase activity of isolated bovine heart enzyme by 50-60% with Ki of ∼1 µM, close to Kd of calcium binding with the oxidase determined spectrophotometrically. The inhibition is observed only at low, but physiologically relevant, turnover rates of the enzyme (∼10 s(-1 or less. No inhibitory effect of Ca(2+ is observed under conventional conditions of cytochrome c oxidase activity assays (turnover number >100 s(-1 at pH 8, which may explain why the effect was not noticed earlier. The inhibition is specific for Ca(2+ and is reversed by EGTA. Na(+ ions that compete with Ca(2+ for binding with the Cation Binding Site, do not affect significantly activity of the enzyme but counteract the inhibitory effect of Ca(2+. The Ca(2+-induced inhibition of cytochrome c oxidase is observed also with the uncoupled mitochondria from several rat tissues. At the same time, calcium ions do not inhibit activity of the homologous bacterial cytochrome oxidases. Possible mechanisms of the inhibition are discussed as well as potential physiological role of Ca(2+ binding with cytochrome oxidase. Ca(2+- binding at the Cation Binding Site is proposed to inhibit proton-transfer through the exit part of the proton conducting pathway H in the mammalian oxidases.

  9. CotA, a multicopper oxidase from Bacillus pumilus WH4, exhibits manganese-oxidase activity.

    Directory of Open Access Journals (Sweden)

    Jianmei Su

    Full Text Available Multicopper oxidases (MCOs are a family of enzymes that use copper ions as cofactors to oxidize various substrates. Previous research has demonstrated that several MCOs such as MnxG, MofA and MoxA can act as putative Mn(II oxidases. Meanwhile, the endospore coat protein CotA from Bacillus species has been confirmed as a typical MCO. To study the relationship between CotA and the Mn(II oxidation, the cotA gene from a highly active Mn(II-oxidizing strain Bacillus pumilus WH4 was cloned and overexpressed in Escherichia coli strain M15. The purified CotA contained approximately four copper atoms per molecule and showed spectroscopic properties typical of blue copper oxidases. Importantly, apart from the laccase activities, the CotA also displayed substantial Mn(II-oxidase activities both in liquid culture system and native polyacrylamide gel electrophoresis. The optimum Mn(II oxidase activity was obtained at 53°C in HEPES buffer (pH 8.0 supplemented with 0.8 mM CuCl2. Besides, the addition of o-phenanthroline and EDTA both led to a complete suppression of Mn(II-oxidizing activity. The specific activity of purified CotA towards Mn(II was 0.27 U/mg. The Km, Vmax and kcat values towards Mn(II were 14.85±1.17 mM, 3.01×10(-6±0.21 M·min(-1 and 0.32±0.02 s(-1, respectively. Moreover, the Mn(II-oxidizing activity of the recombinant E. coli strain M15-pQE-cotA was significantly increased when cultured both in Mn-containing K liquid medium and on agar plates. After 7-day liquid cultivation, M15-pQE-cotA resulted in 18.2% removal of Mn(II from the medium. Furthermore, the biogenic Mn oxides were clearly observed on the cell surfaces of M15-pQE-cotA by scanning electron microscopy. To our knowledge, this is the first report that provides the direct observation of Mn(II oxidation with the heterologously expressed protein CotA, Therefore, this novel finding not only establishes the foundation for in-depth study of Mn(II oxidation mechanisms, but also offers

  10. Enhancement of liposome mediated gene transfer by adding cholesterol and cholesterol modulating drugs.

    Science.gov (United States)

    Bae, Yun-Ui; Huh, Jae-Wan; Kim, Bieong-Kil; Park, Hyeon Young; Seu, Young-Bae; Doh, Kyung-Oh

    2016-12-01

    Cholesterol is an important cell membrane component and has been used as co-lipid for cationic liposome to enhance gene delivery. However, the role of cholesterol in transfection efficiency has not been fully understood. In this study, transfection efficiency of liposome was measured after cholesterol was added to the cell culture medium. As a result, addition of cholesterol increased transfection efficiency of several liposomes consisting of different lipid components in various cells (AGS, CHO, COS7 and, MCF7). Furthermore, treatment of cells with cholesterol modulating drugs, imipramine and U18666A, also increased transfection efficiency of liposomes. To elucidate the role of added cholesterol in gene transfer, endocytotic mechanism was studied and also revealed that adding cholesterol in culture media induced participation of caveolae-mediated endocytosis and micropinocytosis in CHO cell. Therefore, the results of this work suggest that modulation of intracellular cholesterol can be an important method to enhance gene delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Prevention of cholesterol gallstones by inhibiting hepatic biosynthesis and intestinal absorption of cholesterol

    Science.gov (United States)

    Wang, Helen H; Portincasa, Piero; de Bari, Ornella; Liu, Kristina J; Garruti, Gabriella; Neuschwander-Tetri, Brent A; Wang, David Q.-H

    2013-01-01

    Cholesterol cholelithiasis is a multifactorial disease influenced by a complex interaction of genetic and environmental factors, and represents a failure of biliary cholesterol homeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed. The primary pathophysiologic event is persistent hepatic hypersecretion of biliary cholesterol, which has both hepatic and small intestinal components. The majority of the environmental factors are probably related to Western-type dietary habits, including excess cholesterol consumption. Laparoscopic cholecystectomy, one of the most commonly performed surgical procedures in the US, is nowadays a major treatment for gallstones. However, it is invasive and can cause surgical complications, and not all patients with symptomatic gallstones are candidates for surgery. The hydrophilic bile acid, ursodeoxycholic acid (UDCA) has been employed as first-line pharmacological therapy in a subgroup of symptomatic patients with small, radiolucent cholesterol gallstones. Long-term administration of UDCA can promote the dissolution of cholesterol gallstones. However, the optimal use of UDCA is not always achieved in clinical practice because of failure to titrate the dose adequately. Therefore, the development of novel, effective, and noninvasive therapies is crucial for reducing the costs of health care associated with gallstones. In this review, we summarize recent progress in investigating the inhibitory effects of ezetimibe and statins on intestinal absorption and hepatic biosynthesis of cholesterol, respectively, for the treatment of gallstones, as well as in elucidating their molecular mechanisms by which combination therapy could prevent this very common liver disease worldwide. PMID:23419155

  12. Alcohol consumption stimulates early steps in reverse cholesterol transport

    OpenAIRE

    Gaag, M.S.; Tol, A; Vermunt, S.H.F.; Scheek, L.M.; Schaafsma, G.; Hendriks, H.F.J.

    2001-01-01

    Alcohol consumption is associated with increased HDL cholesterol levels, which may indicate stimulated reverse cholesterol transport. The mechanism is, however, not known. The aim of this study was to evaluate the effects of alcohol consumption on the first two steps of the reverse cholesterol pathway: cellular cholesterol efflux and plasma cholesterol esterification. Eleven healthy middle-aged men consumed four glasses (40 g of alcohol) of red wine, beer, spirits (Dutch gin), or carbonated m...

  13. Inhibition of intestinal cholesterol absorption with ezetimibe increases components of reverse cholesterol transport in humans.

    Science.gov (United States)

    Davidson, Michael H; Voogt, Jason; Luchoomun, Jayraz; Decaris, Julie; Killion, Salena; Boban, Drina; Glass, Alexander; Mohammad, Hussein; Lu, Yun; Villegas, Deona; Neese, Richard; Hellerstein, Marc; Neff, David; Musliner, Thomas; Tomassini, Joanne E; Turner, Scott

    2013-10-01

    Reverse cholesterol transport (RCT) can be defined as a pathway of flux of cholesterol from peripheral tissues to the liver for potential excretion into feces. This prospective, placebo-controlled, double-blind crossover study assessed the effect of ezetimibe on several RCT parameters in hyperlipidemic patients. Following 7 weeks of treatment (ezetimibe 10 mg/day or placebo), 26 patients received 24-h continuous IV infusions of [3,4-(13)C2]-cholesterol, then took heavy water ((2)H2O) by mouth. Cholesterol excretion was measured by quantification of neutral/acid sterols in stool and blood samples during 7 days post-infusion with continued treatment. Plasma de novo cholesterol synthesis was assessed by (2)H-labeling from (2)H2O. Ezetimibe significantly reduced levels of low-density lipoprotein cholesterol (22%, P < 0.001) without significant changes in triglycerides and high-density lipoprotein cholesterol and significantly increased the flux of plasma-derived cholesterol into fecal neutral sterols by 52% (P = 0.04) without change in flux into fecal bile acids. Total fecal neutral sterol output increased by 23% (P = 0.02). Plasma de novo cholesterol synthesis increased by 57% (P < 0.001). The fractional clearance rate (FCR) of plasma cholesteryl-ester trended higher (7%; P = 0.055) with a reduction in absolute cholesteryl-ester production rate (9%, P < 0.01). Whole-body free cholesterol efflux rate from extra-hepatic tissues into plasma was not measurably changed by ezetimibe. Ezetimibe treatment approximately doubled the flux of plasma-derived cholesterol into fecal neutral sterols, in association with increases in total fecal neutral sterol excretion, FCR of plasma cholesterol ester, and plasma de novo cholesterol synthesis. These effects are consistent with increased cholesterol transport through the plasma compartment and excretion from the body, in response to ezetimibe treatment in hyperlipidemic humans. Clintrials.gov: NCT00701727. Copyright

  14. Neutrophils to the ROScue: Mechanisms of NADPH Oxidase Activation and Bacterial Resistance

    Directory of Open Access Journals (Sweden)

    Giang T. Nguyen

    2017-08-01

    Full Text Available Reactive oxygen species (ROS generated by NADPH oxidase play an important role in antimicrobial host defense and inflammation. Their deficiency in humans results in recurrent and severe bacterial infections, while their unregulated release leads to pathology from excessive inflammation. The release of high concentrations of ROS aids in clearance of invading bacteria. Localization of ROS release to phagosomes containing pathogens limits tissue damage. Host immune cells, like neutrophils, also known as PMNs, will release large amounts of ROS at the site of infection following the activation of surface receptors. The binding of ligands to G-protein-coupled receptors (GPCRs, toll-like receptors, and cytokine receptors can prime PMNs for a more robust response if additional signals are encountered. Meanwhile, activation of Fc and integrin directly induces high levels of ROS production. Additionally, GPCRs that bind to the bacterial-peptide analog fMLP, a neutrophil chemoattractant, can both prime cells and trigger low levels of ROS production. Engagement of these receptors initiates intracellular signaling pathways, resulting in activation of downstream effector proteins, assembly of the NADPH oxidase complex, and ultimately, the production of ROS by this complex. Within PMNs, ROS released by the NADPH oxidase complex can activate granular proteases and induce the formation of neutrophil extracellular traps (NETs. Additionally, ROS can cross the membranes of bacterial pathogens and damage their nucleic acids, proteins, and cell membranes. Consequently, in order to establish infections, bacterial pathogens employ various strategies to prevent restriction by PMN-derived ROS or downstream consequences of ROS production. Some pathogens are able to directly prevent the oxidative burst of phagocytes using secreted effector proteins or toxins that interfere with translocation of the NADPH oxidase complex or signaling pathways needed for its activation

  15. Effect of Inhibition of Intestinal Cholesterol Absorption on the Prevention of Cholesterol Gallstone Formation.

    Science.gov (United States)

    Portincasa, Piero; Wang, David Q-H

    2017-01-01

    Cholesterol cholelithiasis is a multifactorial hepatobiliary disease. Interactions between genetic and environmental factors play a critical role in biliary cholesterol homeostasis and its imbalance enhances cholelithogenesis. In patients developing symptoms or complications of gallstone disease, laparoscopic cholecystectomy is recommended for treatment of gallstones. In a subgroup of patients with small, radiolucent pure cholesterol gallstones, the hydrophilic bile acid, ursodeoxycholic acid (UDCA) is still considered the only pharmacological therapy able to induce oral litholysis. Identifying novel and effective pharmacological therapies is being investigated. We propose that the specific intestinal Niemann-Pick C1-like 1 protein inhibitor ezetimibe is a potential agent for preventing gallstone formation by reducing bioavailability of intestine- derived cholesterol to the liver for biliary secretion and desaturating bile through the inhibition of intestinal absorption of cholesterol. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. Sphingomyelin synthase overexpression increases cholesterol accumulation and decreases cholesterol secretion in liver cells

    Directory of Open Access Journals (Sweden)

    Li Yue

    2011-03-01

    Full Text Available Abstract Background Studies have shown that plasma high density lipoprotein cholesterol levels are negatively correlated with the development of atherosclerosis, whereas epidemiological studies have also shown that plasma sphingomyelin level is an independent risk factor for atherosclerosis. Methods To evaluate the relationship between cellular sphingomyelin level and cholesterol metabolism, we created two cell lines that overexpressed sphingomyelin synthase 1 or 2 (SMS1 or SMS2, using the Tet-off expression system. Results We found that SMS1 or SMS2 overexpression in Huh7 cells, a human hepatoma cell line, significantly increased the levels of intracellular sphingomyelin, cholesterol, and apolipoprotein A-I and decreased levels of apolipoprotein A-I and cholesterol in the cell culture medium, implying a defect in both processes. Conclusions Our findings indicate that the manipulation of sphingomyelin synthase activity could influence the metabolism of sphingomyelin, cholesterol and apolipoprotein A-I.

  17. Electromagnetic compatibility and interference metrology

    Science.gov (United States)

    Ma, M. T.; Kanda, M.

    1986-07-01

    The material included in the report is intended for a short course on electromagnetic compatibility/interference (EMC/EM) metrology. The entire course is presented in nine chapters with the introductory part given as Chapter 1. The particular measurement topics to be covered are: (1) open sites (Chapters 2 and 6), (2) transverse electromagnetic cells (Chapter 3), (3) techniques for measuring the electromagnetic shielding of materials (Chapter 4), (4) anechoic chambers (Chapter 5), and (5) reverberating chambers (Chapter 8). In addition, since small probe antennas play an important role in some of the EMC/EMI measurements discussed, a separate chapter on various probe systems developed at NBS is given in Chapter 7. Selected contemporary EMI topics such as the characterization and measurement of a complex EM environment, interferences in the form of out-of-band receptions to an antenna, and some conducted EMI problems are also briefly discussed (Chapter 9).

  18. Enzymatic quantification of cholesterol and cholesterol esters from silicone hydrogel contact lenses.

    Science.gov (United States)

    Pucker, Andrew D; Thangavelu, Mirunalni; Nichols, Jason J

    2010-06-01

    The purpose of this work was to develop an enzymatic method of quantification of cholesterol and cholesterol esters derived from contact lenses, both in vitro and ex vivo. Lotrafilcon B (O2 Optix; CIBA Vision, Inc., Duluth, GA) and galyfilcon A (Acuvue Advance; Vistakon, Inc., Jacksonville, FL) silicone hydrogel contact lenses were independently incubated in cholesterol oleate solutions varying in concentrations. After incubation, the lenses were removed and underwent two separate 2:1 chloroform-methanol extractions. After in vitro studies, 10 human subjects wore both lotrafilcon B and galyfilcon A contact lenses for 7 days. The lenses also underwent two separate 2:1 chloroform-methanol extractions. All in vitro and ex vivo samples were quantified with a cholesterol esterase enzymatic reaction. Calibration curves from quantifications of in vitro contact lens samples soaked in successively decreasing concentrations of cholesterol oleate yielded coefficients of determination (R(2)) of 0.99 (lotrafilcon B) and 0.97 (galyfilcon A). For in vitro contact lens samples, galyfilcon A was associated with an average cholesterol oleate extraction of 39.85 +/- 48.65 microg/lens, whereas lotrafilcon B was associated with 5.86 +/- 3.36 microg/lens (P = 0.05) across both extractions and all incubation concentrations. For ex vivo contact lens samples, there was significantly more cholesterol and cholesterol esters deposited on galyfilcon A (5.77 +/- 1.87 microg/lens) than on lotrafilcon B (2.03 +/- 1.62 microg/lens; P = 0.0005). This is an efficient and simple method of quantifying total cholesterol extracted from silicone hydrogel contact lenses and, potentially, the meibum and/or tear film. Certain silicone hydrogel materials demonstrate more affinity for cholesterol and its esters than do others.

  19. Image hiding using optical interference

    Science.gov (United States)

    Zhang, Yan; Wang, Weining

    2010-09-01

    Optical image encryption technology has attracted a lot of attentions due to its large capacitance and fast speed. In conventional image encryption methods, the random phase masks are used as encryption keys to encode the images into white noise distribution. Therefore, this kind of methods requires interference technology to record complex amplitude and is vulnerable to attack techniques. The image hiding methods which employ the phase retrieve algorithm to encode the images into two or more phase masks are proposed, the hiding process is carried out within a computer using iterative algorithm. But the iterative algorithms are time consumed. All method mentioned above are based on the optical diffraction of the phase masks. In this presentation, a new optical image hiding method based on optical interference is proposed. The coherence lights which pass through two phase masks are combined by a beam splitter. Two beams interfere with each other and the desired image appears at the pre-designed plane. Two phase distribution masks are design analytically; therefore, the hiding speed can be obviously improved. Simulation results are carried out to demonstrate the novelty of the new proposed methods. This method can be expanded for double images hiding.

  20. Quantum interference in plasmonic circuits.

    Science.gov (United States)

    Heeres, Reinier W; Kouwenhoven, Leo P; Zwiller, Valery

    2013-10-01

    Surface plasmon polaritons (plasmons) are a combination of light and a collective oscillation of the free electron plasma at metal/dielectric interfaces. This interaction allows subwavelength confinement of light beyond the diffraction limit inherent to dielectric structures. As a result, the intensity of the electromagnetic field is enhanced, with the possibility to increase the strength of the optical interactions between waveguides, light sources and detectors. Plasmons maintain non-classical photon statistics and preserve entanglement upon transmission through thin, patterned metallic films or weakly confining waveguides. For quantum applications, it is essential that plasmons behave as indistinguishable quantum particles. Here we report on a quantum interference experiment in a nanoscale plasmonic circuit consisting of an on-chip plasmon beamsplitter with integrated superconducting single-photon detectors to allow efficient single plasmon detection. We demonstrate a quantum-mechanical interaction between pairs of indistinguishable surface plasmons by observing Hong-Ou-Mandel (HOM) interference, a hallmark non-classical interference effect that is the basis of linear optics-based quantum computation. Our work shows that it is feasible to shrink quantum optical experiments to the nanoscale and offers a promising route towards subwavelength quantum optical networks.

  1. Cooperative Algorithms for MIMO Interference Channels

    CERN Document Server

    Peters, Steven W

    2010-01-01

    Interference alignment is a transmission technique for exploiting all available degrees of freedom in the interference channel with an arbitrary number of users. Most prior work on interference alignment, however, neglects interference from other nodes in the network not participating in the alignment operation. This paper proposes three generalizations of interference alignment for the multiple-antenna interference channel with multiple users that account for colored noise, which models uncoordinated interference. First, a minimum interference-plus-noise leakage algorithm is presented, and shown to be equivalent to previous subspace methods when noise is spatially white or negligible. A joint minimum mean squared error design is then proposed that jointly optimizes the transmit precoders and receive spatial filters, whereas previous designs neglect the receive spatial filter. This algorithm is shown to be a generalization of previous joint MMSE designs for other system configurations such as the broadcast ch...

  2. Carbon nanostructure composite for electromagnetic interference ...

    Indian Academy of Sciences (India)

    2015-05-30

    based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference.

  3. Two pathways of activation of the superoxide-generating NADPH oxidase of phagocytes in vitro--distinctive effects of inhibitors.

    Science.gov (United States)

    Sigal, Natalia; Gorzalczany, Yara; Pick, Edgar

    2003-06-01

    The NADPH oxidase complex of phagocytes comprises a membrane-associated flavocytochrome b559, and 4 cytosolic components: p47phox, p67phox, p40phox, and the small GTPase Rac. Activation of the oxidase in vivo is the result of assembly of the cytosolic components with cytochrome b559 and is mimicked in vitro by a cell-free system consisting of membranes, p47phox, p67phox, nonprenylated or prenylated Rac, and an anionic amphiphile as activator (defined as "p47phox and amphiphile-dependent" or canonical pathway). We reported that prenylated Rac1 is capable of activating the NADPH oxidase in vitro in the absence of p47phox and amphiphile (defined as "p47phox and amphiphile-independent" pathway). We now demonstrate that the 2 pathways exhibit distinctive susceptibilities to inhibitors: 1) The anionic amphiphile lithium dodecyl sulfate, an activator of the canonical pathway, has the opposite effect (inhibition) on oxidase activation by prenylated Rac and p67phox; 2) GDP and, paradoxically, GTP (but not GMP, ATP, ADP, and AMP) prevent oxidase activation by the p47phox and amphiphile-independent pathway but do not affect activation by the canonical pathway; 3) The Rac-binding domain of p21-activated kinase is a potent inhibitor of activation by the p47phox and amphiphile-independent pathway while exerting a milder inhibitory effect on the canonical pathway; 4) The C-terminal polybasic Rac1 peptide 177-191 and the cationic antibiotic neomycin sulfate inhibit activation by the canonical pathway but do not affect activation by the p47phox and amphiphile-independent pathway; 5) Binding of prenylated Rac1 to membrane-mimicking phospholipid vesicles is, nevertheless, enhanced when these contain negatively charged lipids. It is proposed that preferential inhibition of oxidase activation, via the p47phox and amphiphile-independent pathway, is a reflection of interference by the inhibitors with Rac-dependent recruitment of p67phox to the membrane.

  4. Free cholesterol and cholesterol esters in bovine oocytes: Implications in survival and membrane raft organization after cryopreservation.

    Science.gov (United States)

    Buschiazzo, Jorgelina; Ríos, Glenda L; Canizo, Jesica R; Antollini, Silvia S; Alberio, Ricardo H

    2017-01-01

    Part of the damage caused by cryopreservation of mammalian oocytes occurs at the plasma membrane. The addition of cholesterol to cell membranes as a strategy to make it more tolerant to cryopreservation has been little addressed in oocytes. In order to increase the survival of bovine oocytes after cryopreservation, we proposed not only to increase cholesterol level of oocyte membranes before vitrification but also to remove the added cholesterol after warming, thus recovering its original level. Results from our study showed that modulation of membrane cholesterol by methyl-β-cyclodextrin (MβCD) did not affect the apoptotic status of oocytes and improved viability after vitrification yielding levels of apoptosis closer to those of fresh oocytes. Fluorometric measurements based on an enzyme-coupled reaction that detects both free cholesterol (membrane) and cholesteryl esters (stored in lipid droplets), revealed that oocytes and cumulus cells present different levels of cholesterol depending on the seasonal period. Variations at membrane cholesterol level of oocytes were enough to account for the differences found in total cholesterol. Differences found in total cholesterol of cumulus cells were explained by the differences found in both the content of membrane cholesterol and of cholesterol esters. Cholesterol was incorporated into the oocyte plasma membrane as evidenced by comparative labeling of a fluorescent cholesterol. Oocytes and cumulus cells increased membrane cholesterol after incubation with MβCD/cholesterol and recovered their original level after cholesterol removal, regardless of the season. Finally, we evaluated the effect of vitrification on the putative raft molecule GM1. Cholesterol modulation also preserved membrane organization by maintaining ganglioside level at the plasma membrane. Results suggest a distinctive cholesterol metabolic status of cumulus-oocyte complexes (COCs) among seasons and a dynamic organizational structure of cholesterol

  5. Free cholesterol and cholesterol esters in bovine oocytes: Implications in survival and membrane raft organization after cryopreservation.

    Directory of Open Access Journals (Sweden)

    Jorgelina Buschiazzo

    Full Text Available Part of the damage caused by cryopreservation of mammalian oocytes occurs at the plasma membrane. The addition of cholesterol to cell membranes as a strategy to make it more tolerant to cryopreservation has been little addressed in oocytes. In order to increase the survival of bovine oocytes after cryopreservation, we proposed not only to increase cholesterol level of oocyte membranes before vitrification but also to remove the added cholesterol after warming, thus recovering its original level. Results from our study showed that modulation of membrane cholesterol by methyl-β-cyclodextrin (MβCD did not affect the apoptotic status of oocytes and improved viability after vitrification yielding levels of apoptosis closer to those of fresh oocytes. Fluorometric measurements based on an enzyme-coupled reaction that detects both free cholesterol (membrane and cholesteryl esters (stored in lipid droplets, revealed that oocytes and cumulus cells present different levels of cholesterol depending on the seasonal period. Variations at membrane cholesterol level of oocytes were enough to account for the differences found in total cholesterol. Differences found in total cholesterol of cumulus cells were explained by the differences found in both the content of membrane cholesterol and of cholesterol esters. Cholesterol was incorporated into the oocyte plasma membrane as evidenced by comparative labeling of a fluorescent cholesterol. Oocytes and cumulus cells increased membrane cholesterol after incubation with MβCD/cholesterol and recovered their original level after cholesterol removal, regardless of the season. Finally, we evaluated the effect of vitrification on the putative raft molecule GM1. Cholesterol modulation also preserved membrane organization by maintaining ganglioside level at the plasma membrane. Results suggest a distinctive cholesterol metabolic status of cumulus-oocyte complexes (COCs among seasons and a dynamic organizational structure

  6. Cholesterol Removal from Adult Skeletal Muscle impairs Excitation-Contraction Coupling and Aging reduces Caveolin-3 and alters the Expression of other Triadic Proteins

    Directory of Open Access Journals (Sweden)

    Genaro eBarrientos

    2015-04-01

    Full Text Available Cholesterol and caveolin are integral membrane components that modulate the function/location of many cellular proteins. Skeletal muscle fibers, which have unusually high cholesterol levels in transverse tubules, express the caveolin-3 isoform but its association with transverse tubules remains contentious. Cholesterol removal impairs excitation-contraction coupling in amphibian and mammalian fetal skeletal muscle fibers. Here, we show that treating single muscle fibers from adult mice with the cholesterol removing agent methyl-β-cyclodextrin decreased fiber cholesterol by 26%, altered the location pattern of caveolin-3 and of the voltage dependent calcium channel Cav1.1, and suppressed or reduced electrically evoked Ca2+ transients without affecting membrane integrity or causing sarcoplasmic reticulum calcium depletion. We found that transverse tubules from adult muscle and triad fractions that contain ~10% attached transverse tubules, but not sarcoplasmic reticulum membranes, contained caveolin-3 and Cav1.1; both proteins partitioned into detergent-resistant membrane fractions highly enriched in cholesterol. Aging entails significant deterioration of skeletal muscle function. We found that triad fractions from aged rats had similar cholesterol and RyR1 protein levels compared to triads from young rats, but had lower caveolin-3 and glyceraldehyde 3-phosphate dehydrogenase and increased Na+/K+-ATPase protein levels. Both triad fractions had comparable NADPH oxidase (NOX activity and protein content of NOX2 subunits (p47phox and gp91phox, implying that NOX activity does not increase during aging. These findings show that partial cholesterol removal impairs excitation-contraction coupling and alters caveolin-3 and Cav1.1 location pattern, and that aging reduces caveolin-3 protein content and modifies the expression of other triadic proteins. We discuss the possible implications of these findings for skeletal muscle function in young and aged

  7. Structure of cholesterol/ceramide monolayer mixtures

    DEFF Research Database (Denmark)

    Scheffer, L.; Solomonov, I.; Weygand, M.J.

    2005-01-01

    The structure of monolayers of cholesterol/ ceramide mixtures was investigated using grazing incidence x-ray diffraction, immunofluorescence, and atomic force microscopy techniques. Grazing incidence x-ray diffraction measurements showed the existence of a crystalline mixed phase of the two...... that in uncompressed ceramide monolayers, the highly crystalline phase coexists with a disordered loosely packed phase. In contrast, no disordered phase coexists with the new crystalline mixed phase. We conclude that the new mixed phase represents a stable homogeneous arrangement of cholesterol with ceramide...... components within a range of compositions of cholesterol/ ceramide between 100: 0 and 67: 33. The mixed phase coexists with the ceramide crystalline phase in the range of compositions between 50: 50 and 30: 70; between 30: 70 and 0: 100 only the highly crystalline phase of ceramide was detected. The latter...

  8. Ordering effects of cholesterol and its analogues

    DEFF Research Database (Denmark)

    Róg, Tomasz; Pasenkiewicz-Gierula, Marta; Vattulainen, Ilpo

    2009-01-01

    Without any exaggeration, cholesterol is one of the most important lipid species in eukaryotic cells. Its effects on cellular membranes and functions range from purely mechanistic to complex metabolic ones, besides which it is also a precursor of the sex hormones (steroids) and several vitamins....... In this review, we discuss the biophysical effects of cholesterol on the lipid bilayer, in particular the ordering and condensing effects, concentrating on the molecular level or inter-atomic interactions perspective, starting from two-component systems and proceeding to many-component ones e.g., modeling lipid...... rafts. Particular attention is paid to the roles of the methyl groups in the cholesterol ring system, and their possible biological function. Although our main research methodology is computer modeling, in this review we make extensive comparisons between experiments and different modeling approaches....

  9. CHOBIMALT: A Cholesterol-Based Detergent†

    Science.gov (United States)

    Howell, Stanley C.; Mittal, Ritesh; Huang, Lijun; Travis, Benjamin; Breyer, Richard M.; Sanders, Charles R.

    2010-01-01

    Cholesterol and its hemisuccinate and sulfate derivatives are widely used in studies of purified membrane proteins, but are difficult to solubilize in aqueous solution, even in the presence of detergent micelles. Other cholesterol derivatives do not form conventional micelles and lead to viscous solutions. To address these problems a cholesterol-based detergent, CHOBIMALT, has been synthesized and characterized. At concentrations above 3–4μM, CHOBIMALT forms micelles without the need for elevated temperatures or sonic disruption. Diffusion and fluorescence measurements indicated that CHOBIMALT micelles are large (210 ± 30 kDa). The ability to solubilize a functional membrane protein was explored using a G-protein coupled receptor, the human kappa opioid receptor type 1 (hKOR1). While CHOBIMALT alone was not found to be effective as a surfactant for membrane extraction, when added to classical detergent micelles CHOBIMALT was observed to dramatically enhance the thermal stability of solubilized hKOR1. PMID:20919740

  10. Controlling multimode optomechanical interactions via interference

    Science.gov (United States)

    Kuzyk, Mark C.; Wang, Hailin

    2017-08-01

    We demonstrate optomechanical interference in a multimode system, in which an optical mode couples to two mechanical modes. A phase-dependent excitation-coupling approach is developed, which enables the observation of destructive interference in dynamical backactions. The destructive interference prevents the coupling of the mechanical system to the optical mode, suppressing optically induced mechanical damping. These studies establish optomechanical interference as an essential tool for controlling the interactions between light and mechanical oscillators.

  11. Distributed Interference Alignment with Low Overhead

    CERN Document Server

    Ma, Yanjun; Chen, Rui

    2011-01-01

    Based on closed-form interference alignment (IA) solutions, a low overhead distributed interference alignment (LOIA) scheme is proposed in this paper for the $K$-user SISO interference channel, and extension to multiple antenna scenario is also considered. Compared with the iterative interference alignment (IIA) algorithm proposed by Gomadam et al., the overhead is greatly reduced. Simulation results show that the IIA algorithm is strictly suboptimal compared with our LOIA algorithm in the overhead-limited scenario.

  12. [Screening and optimization of cholesterol conversion strain].

    Science.gov (United States)

    Fan, Dan; Xiong, Bingjian; Pang, Cuiping; Zhu, Xiangdong

    2014-10-04

    Bacterial strain SE-1 capable of transforming cholesterol was isolated from soil and characterized. The transformation products were identified. Fermentation conditions were optimized for conversion. Cholesterol was used as sole carbon source to isolate strain SE-1. Morphology, physiological and biochemical characteristics of strain SE-1 were studied. 16S rRNA gene was sequenced and subjected to phylogenetic analysis. Fermentation supernatants were extracted with chloroform, the transformation products were analyzed by silica gel thin layer chromatography and Sephadex LH20. Their structures were identified by 1H-NMR and 13C-NMR. Fermentation medium including carbon and nitrogen, methods of adding substrates and fermentation conditions for Strain SE-1 were optimized. Strain SE-1 was a Gram-negative bacterium, exhibiting the highest homologs to Burkholderia cepacia based on the physiological analysis. The sequence analysis of 16S rRNA gene of SE-1 strain and comparison with related Burkholderia show that SE-1 strain was very close to B. cepacia (Genbank No. U96927). The similarity was 99%. The result of silica gel thin layer chromatography shows that strain SE-1 transformed cholesterol to two products, 7beta-hydroxycholesterol and the minor product was 7-oxocholesterol. The optimum culture conditions were: molasses 5%, (NH4 )2SO4 0.3%, 4% of inoculation, pH 7.5 and 36 degrees C. Under the optimum culture condition, the conversion rate reached 34.4% when concentration of cholesterol-Tween 80 was 1 g/L. Cholesterol 7beta-hydroxylation conversion rate under optimal conditions was improved by 20.8%. Strain SE-1 isolated from soil is capable of converting cholesterol at lab-scale.

  13. Tympanomastoid cholesterol granulomas: Immunohistochemical evaluation of angiogenesis.

    Science.gov (United States)

    Iannella, Giannicola; Di Gioia, Cira; Carletti, Raffaella; Magliulo, Giuseppe

    2017-08-01

    This study investigates the immunohistochemical expression of vascular endothelial growth factor (VEGF) and CD34 in patients treated for middle ear and mastoid cholesterol granulomas to evaluate the angiogenesis and vascularization of this type of lesion. A correlation between the immunohistochemical data and the radiological and intraoperative evidence of temporal bone marrow invasion and blood source connection was performed to validate this hypothesis. Retrospective study. Immunohistochemical expression of VEGF and CD34 in a group of 16 patients surgically treated for cholesterol granuloma was examined. Middle ear cholesteatomas with normal middle ear mucosa and external auditory canal skin were used as the control groups. The radiological and intraoperative features of cholesterol granulomas were also examined. In endothelial cells, there was an increased expression of angiogenetic growth factor receptors in all the cholesterol granulomas in this study. The quantitative analysis of VEGF showed a mean value of 37.5, whereas the CD34 quantitative analysis gave a mean value of 6.8. Seven patients presented radiological or intraoperative evidence of bone marrow invasion, hematopoietic potentialities, or blood source connections that might support the bleeding theory. In all of these cases there was computed tomography or intraoperative evidence of bone erosion of the middle ear and/or temporal bone structures. The mean values of VEGF and CD34 were 41.1 and 7.7, respectively. High values of VEGF and CD34 are present in patients with cholesterol granulomas. Upregulation of VEGF and CD34 is indicative of a remarkable angiogenesis and a widespread vascular concentration in cholesterol granulomas. 3b. Laryngoscope, 127:E283-E290, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  14. Structure and activity of Aspergillus nidulans copper amine oxidase.

    Science.gov (United States)

    McGrath, Aaron P; Mithieux, Suzanne M; Collyer, Charles A; Bakhuis, Janny G; van den Berg, Marco; Sein, Arjen; Heinz, Andrea; Schmelzer, Christian; Weiss, Anthony S; Guss, J Mitchell

    2011-06-28

    Aspergillus nidulans amine oxidase (ANAO) has the unusual ability among the family of copper and trihydroxyphenylalanine quinone-containing amine oxidases of being able to oxidize the amine side chains of lysine residues in large peptides and proteins. We show here that in common with the related enzyme from the yeast Pichia pastoris, ANAO can promote the cross-linking of tropoelastin and oxidize the lysine residues in α-casein proteins and tropoelastin. The crystal structure of ANAO, the first for a fungal enzyme in this family, has been determined to a resolution of 2.4 Å. The enzyme is a dimer with the archetypal fold of a copper-containing amine oxidase. The active site is the most open of any of those of the structurally characterized enzymes in the family and provides a ready explanation for its lysine oxidase-like activity.

  15. Improved Oxidase Mimetic Activity by Praseodymium Incorporation into Ceria Nanocubes.

    Science.gov (United States)

    Jiang, Lei; Fernandez-Garcia, Susana; Tinoco, Miguel; Yan, Zhaoxia; Xue, Qi; Blanco, Ginesa; Calvino, Jose J; Hungria, Ana B; Chen, Xiaowei

    2017-06-07

    Ceria nanocubes (NC) modified with increasing concentrations of praseodymium (5, 10, 15, and 20 mol %) have been successfully synthesized by a hydrothermal method. The as-synthesized Pr-modified ceria nanocubes exhibit an enhanced oxidase-like activity on the organic dye TMB within a wide range of concentrations and durations. The oxidase activity increases with increasing Pr amounts in Pr-modified ceria nanocubes within the investigated concentration range. Meanwhile, these Pr-modified ceria nanocubes also show higher reducibility than pure ceria nanocubes. The kinetics of their oxidase mimetic activity is fitted with the Michaelis-Menten equation. A mechanism has been proposed on how the Pr incorporation could affect the energy level of the bands in ceria and hence facilitate the TMB oxidation reaction. The presence of Pr(3+) species on the surface also contributes to the increasing activity of the Pr-modified ceria nanocubes present higher oxidase activity than pure ceria nanocubes.

  16. Inhibitory activity of xanthine oxidase by fractions Crateva adansonii

    National Research Council Canada - National Science Library

    Abdullahi, A; Hamzah, RU; Jigam, AA; Yahya, A; Kabiru, AY; Muhammad, H; Sakpe, S; Adefolalu, FS; Isah, MC; Kolo, MZ

    2012-01-01

    ...: Xanthine oxidase inhibitory activity was assayed spectrophotometrically and the degree of enzyme inhibition was determined by measuring the increase in absorbance at 295 nm associated with uric acid formation...

  17. Gibberellin oxidase activities in Bradyrhizobium japonicum bacteroids.

    Science.gov (United States)

    Méndez, Constanza; Baginsky, Cecilia; Hedden, Peter; Gong, Fan; Carú, Margarita; Rojas, María Cecilia

    2014-02-01

    Bradyrhizobium japonicum bacteroids isolated from root nodules of soybean (Glycine max.) plants converted the gibberellin (GA) precursor [(14)C1]GA12 into several products identified by combined gas chromatography-mass spectrometry as [(14)C1]GA24, [(14)C1]GA9, [(14)C1]GA15, GA9 17-nor-16-one and unidentified products. The oxidation of GA12, catalyzed by the GA 20-oxidase, was present in symbiotic bacteroids from plants around flowering, but not in bacteroids from plants at either an early vegetative stage or at late growth stages. Expression of cps and ks genes, involved in ent-kaurene biosynthesis, was also demonstrated in bacteroids from soybean plants around flowering. Earlier precursors of the GA pathway, ent-[(14)C1]kaurenoic acid or [(14)C4]GA12-aldehyde, were efficiently utilized by B. japonicum bacteroids to give labelled GA9 plus intermediates partially oxidized at C-20, as well as GA9 17-nor-16-one and an unidentified product. No 3β or 13-hydroxylated [(14)C]GAs were detected in any of the incubations. Moreover the C19-GAs [(14)C1]GA4 or [(14)C1]GA20 were recovered unconverted upon incubation with the bacteroids which supports the absence of GA 3β-hydroxylase activity in B. japonicum. The bacterial 20-oxidase utilized the 13-hydroxylated substrates [(14)C1]GA53, [(14)C1]GA44 or [(14)C1]GA19, although with less efficiency than [(14)C1]GA12 to give [(14)C1]GA20 as final product, while the 3β-hydroxylated substrate [(14)C1]GA14 was converted to [(14)C1]GA4 to a very small extent. Endogenous GA9 and GA24 were identified by GC-MS in methanolic nodule extracts. These results suggest that B. japonicum bacteroids would synthesize GA9 under the symbiotic conditions present in soybean root nodules. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Dietary cholesterol from eggs increases the ratio of total cholesterol to high-density lipoprotein cholesterol in humans : a meta-analysis

    NARCIS (Netherlands)

    Weggemans, R.M.; Zock, P.L.; Katan, M.B.

    2001-01-01

    Several epidemiologic studies found no effect of egg consumption on the risk of coronary heart disease. It is possible that the adverse effect of eggs on LDL-cholesterol is offset by their favorable effect on HDL cholesterol. Objective: The objective was to review the effect of dietary cholesterol

  19. 47 CFR 24.237 - Interference protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Interference protection. 24.237 Section 24.237... SERVICES Broadband PCS § 24.237 Interference protection. (a) All licensees are required to coordinate their... proposed facilities will not cause interference to existing OFS stations within the coordination distance...

  20. 47 CFR 27.1221 - Interference protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Interference protection. 27.1221 Section 27... Technical Standards § 27.1221 Interference protection. (a) Interference protection will be afforded to BRS... station relative to a base station in another GSA, is equal to the distance, in kilometers, from the base...

  1. Interference mitigation techniques in wireless communications ...

    African Journals Online (AJOL)

    Co-Channel Interference, Intersymbol interference and fading are major impairment to the high-capacity transmission in power- and band-limited wireless communication channel. This paper presents an overview of interference mitigation techniques in wireless communications systems. Linear filtering, equalization, and ...

  2. Impact of MIMO Co-Channel Interference

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; De Carvalho, Elisabeth; Prasad, Ramjee

    2007-01-01

    to cellular interference of some specific Multiple Input Multiple Output (MIMO) schemes on the same and other MIMO schemes. The goal is to study the impact of interference from MIMO schemes at a user located in the cell edge. Semi-Analytical evaluations of Signal to Interference and Noise Ratio (SINR) is done...

  3. An accumulator model of semantic interference

    NARCIS (Netherlands)

    van Maanen, Leendert; van Rijn, Hedderik

    To explain latency effects in picture-word interference tasks, cognitive models need to account for both interference and stimulus onset asynchrony (SOA) effects. As opposed to most models of picture-word interference, which model the time course during the task in a ballistic manner, the RACE model

  4. Cholesterol mediates membrane curvature during fusion events.

    Science.gov (United States)

    Ivankin, Andrey; Kuzmenko, Ivan; Gidalevitz, David

    2012-06-08

    Biomembranes undergo extensive shape changes as they perform vital cellular functions. The mechanisms by which lipids and proteins control membrane curvature remain unclear. We use x-ray reflectivity, grazing incidence x-ray diffraction, and epifluorescence microscopy to study binding of HIV-1 glycoprotein gp41's membrane-bending domain to DPPC/cholesterol monolayers of various compositions at the air-liquid interface. The results offer a new insight into how membrane curvature could be regulated by cholesterol during fusion of the viral lipid envelope and the host cell membranes.

  5. Cholesterol oxidation products and their biological importance

    DEFF Research Database (Denmark)

    Kulig, Waldemar; Cwiklik, Lukasz; Jurkiewicz, Piotr

    2016-01-01

    and precisely regulated level, with an excess of cholesterol. Like cholesterol, many oxysterols are hydrophobic and hence confined to cell membranes. However, small chemical differences between the sterols can significantly affect how they interact with other membrane components, and this in turn can have...... a substantial effect on membrane properties. In this spirit, this review describes the biological importance and the roles of oxysterols in the human body. We focus primarily on the effect of oxysterols on lipid membranes, but we also consider other issues such as enzymatic and nonenzymatic synthesis processes...

  6. An immunoreactive xanthine oxidase protein-possessing xanthinuria and her family.

    Science.gov (United States)

    Yamamoto, T; Moriwaki, Y; Suda, M; Takahashi, S; Hada, T; Nanahoshi, M; Agbedana, E O; Higashino, K

    1992-06-15

    The presence of immunoreactive xanthine oxidase protein was proven in a xanthinuric patient, using a polyclonal antibody against xanthine oxidase. The antibody was raised against purified human liver xanthine oxidase in a rabbit. Double immunodiffusion method demonstrated the existence of an immunologically reactive xanthine oxidase which did not possess xanthine oxidase activity. In addition, urinary excretion of oxypurines in the patient and her family was investigated. The results indicated that a brother and a sister had xanthinuria.

  7. Inhibition of xanthine oxidase by Puerto Rican plant extracts.

    Science.gov (United States)

    Guerrero, R O; Guzman, A L

    1998-12-01

    This study was conducted to search for xanthine oxidase inhibitors in natural products obtained from plants collected in Puerto Rico and to assess the influence of these extracts in the prevention of cataractogenesis. Allopurinol is currently a xanthine oxidase inhibitor used in the treatment of gout. New alternatives with increased therapeutic activity and less side effects should be investigated. Preclusion of cataractogenesis in diabetic rats is also the focus of this investigation. Natural products in the form of plant extracts from Puerto Rico offer a rich and relatively untapped source for the discovery of new drugs that may address these kind of problems. Nineteen collections of Myrtaceae plant extracts were screened for xanthine oxidase inhibition. A spectrophotometrical method was used employing allopurinol as positive control and a blank as negative control. A protocol of the assay with slight modifications was followed from the literature. Two extracts with the highest percentages of xanthine oxidase inhibition were evaluated for possible prevention of cataractogenesis in streptozotocin diabetic rats. The animals were given to drink these plant extracts ad libitum for three months while controls received water. The appearance of cataracts was assessed physically. Two of the nineteen plant extracts showed high inhibition percentages of xanthine oxidase. Eucalyptus deglupta and Syzygium malaccense displayed 51% and 64% inhibitions (IC50 44.5 micrograms/ml and IC50 51 micrograms/ml), respectively. As for the cataractogenesis inhibition, laboratory animals that drank E. deglupta for three months did not develop cataracts. Two plant extracts provided positive results with varying degrees of inhibition of xanthine oxidase. S. malaccense demonstrated the greatest xanthine oxidase inhibitory activity whereas E. deglupta presented the best finding for cataractogenesis prevention. The procedures used in this investigation are useful for the in vitro screening of

  8. Androgen receptor and monoamine oxidase polymorphism in wild bonobos

    OpenAIRE

    Garai, Cintia; Furuichi, Takeshi; Kawamoto, Yoshi; Ryu, Heungjin; Inoue-Murayama, Miho

    2014-01-01

    Androgen receptor gene (AR), monoamine oxidase A gene (MAOA) and monoamine oxidase B gene (MAOB) have been found to have associations with behavioral traits, such as aggressiveness, and disorders in humans. However, the extent to which similar genetic effects might influence the behavior of wild apes is unclear. We examined the loci AR glutamine repeat (ARQ), AR glycine repeat (ARG), MAOA intron 2 dinucleotide repeat (MAin2) and MAOB intron 2 dinucleotide repeat (MBin2) in 32 wild bonobos, Pa...

  9. Inhibitory activity of xanthine oxidase by fractions Crateva adansonii

    OpenAIRE

    A Abdullahi; RU Hamzah; AA Jigam; Yahya, A.; AY Kabiru; Muhammad, H.; S Sakpe; FS Adefolalu; MC Isah; MZ Kolo

    2012-01-01

    Objective: To study the inhibitory effect of various extracts from Crateva adansonii (C. adansonii) used traditionally against several inflammatory diseases such as rheumatism, arthritis, and gout, was investigated on purified bovine milk xanthine oxidase (XO) activity. Methods: Xanthine oxidase inhibitory activity was assayed spectrophotometrically and the degree of enzyme inhibition was determined by measuring the increase in absorbance at 295 nm associated with uric acid formation. Enzy...

  10. 2013 Cholesterol Guidelines Revisited: Percent LDL Cholesterol Reduction or Attained LDL Cholesterol Level or Both for Prognosis?

    NARCIS (Netherlands)

    Bangalore, Sripal; Fayyad, Rana; Kastelein, John J.; Laskey, Rachel; Amarenco, Pierre; Demicco, David A.; Waters, David D.

    2016-01-01

    The 2013 American College of Cardiology (ACC)/American Heart Association (AHA) guideline on the treatment of blood cholesterol recommends moderate- to high-intensity statins for patients with atherosclerotic cardiovascular disease but departs from the traditional treat-to-target approach. Whether

  11. Aspirin Increases the Solubility of Cholesterol in Lipid Membranes

    Science.gov (United States)

    Alsop, Richard; Barrett, Matthew; Zheng, Sonbo; Dies, Hannah; Rheinstadter, Maikel

    2014-03-01

    Aspirin (ASA) is often prescribed for patients with high levels of cholesterol for the secondary prevention of myocardial events, a regimen known as the Low-Dose Aspirin Therapy. We have recently shown that Aspirin partitions in lipid bilayers. However, a direct interplay between ASA and cholesterol has not been investigated. Cholesterol is known to insert itself into the membrane in a dispersed state at moderate concentrations (under ~37.5%) and decrease fluidity of membranes. We prepared model lipid membranes containing varying amounts of both ASA and cholesterol molecules. The structure of the bilayers as a function of ASA and cholesterol concentration was determined using high-resolution X-ray diffraction. At cholesterol levels of more than 40mol%, immiscible cholesterol plaques formed. Adding ASA to the membranes was found to dissolve the cholesterol plaques, leading to a fluid lipid bilayer structure. We present first direct evidence for an interaction between ASA and cholesterol on the level of the cell membrane.

  12. [Basic mechanisms: absorption and excretion of cholesterol and other sterols].

    Science.gov (United States)

    Cofan Pujol, Montserrat

    2014-01-01

    Cholesterol is of vital importance for vertebrate cell membrane structure and function. It is obvious that adequate regulation of cholesterol homeostasis is essential. Hypercholesterolemia promotes atherosclerosis and thereby represents a major risk factor for cardiovascular disease. The liver has been considered the major site of control in maintenance of cholesterol homeostasis. The liver facilitates clearance of (very) low density lipoprotein particles and cholesterol-containing chylomicron remnants, synthesizes cholesterol, synthesizes and secretes (nascent) high density lipoprotein particles, secretes cholesterol and bile salts to bile, and is involved in reverse cholesterol transport. In recent years, however, the importance of the intestine in many aspects of cholesterol physiology is increasingly recognized. It has become apparent that direct secretion of cholesterol from the blood compartment into the intestine, or transintestinal cholesterol excretion, plays a major role in disposal of cholesterol via the feces. This review will discuss current knowledge on the physiology of cholesterol homeostasis, with emphasis on cholesterol absorption, cholesterol synthesis and fecal excretion, and therapeutic options for hypercholesterolemia. Copyright © 2013 Elsevier España, S.L. y SEA. All rights reserved.

  13. Lysyl oxidase activity regulates oncogenic stress response and tumorigenesis.

    Science.gov (United States)

    Wiel, C; Augert, A; Vincent, D F; Gitenay, D; Vindrieux, D; Le Calvé, B; Arfi, V; Lallet-Daher, H; Reynaud, C; Treilleux, I; Bartholin, L; Lelievre, E; Bernard, D

    2013-10-10

    Cellular senescence, a stable proliferation arrest, is induced in response to various stresses. Oncogenic stress-induced senescence (OIS) results in blocked proliferation and constitutes a fail-safe program counteracting tumorigenesis. The events that enable a tumor in a benign senescent state to escape from OIS and become malignant are largely unknown. We show that lysyl oxidase activity contributes to the decision to maintain senescence. Indeed, in human epithelial cell the constitutive expression of the LOX or LOXL2 protein favored OIS escape, whereas inhibition of lysyl oxidase activity was found to stabilize OIS. The relevance of these in vitro observations is supported by in vivo findings: in a transgenic mouse model of aggressive pancreatic ductal adenocarcinoma (PDAC), increasing lysyl oxidase activity accelerates senescence escape, whereas inhibition of lysyl oxidase activity was found to stabilize senescence, delay tumorigenesis, and increase survival. Mechanistically, we show that lysyl oxidase activity favors the escape of senescence by regulating the focal-adhesion kinase. Altogether, our results demonstrate that lysyl oxidase activity participates in primary tumor growth by directly impacting the senescence stability.

  14. Inhibition of human vascular NADPH oxidase by apocynin derived oligophenols.

    Science.gov (United States)

    Mora-Pale, Mauricio; Weïwer, Michel; Yu, Jingjing; Linhardt, Robert J; Dordick, Jonathan S

    2009-07-15

    Enzymatic oxidation of apocynin, which may mimic in vivo metabolism, affords a large number of oligomers (apocynin oxidation products, AOP) that inhibit vascular NADPH oxidase. In vitro studies of NADPH oxidase activity were performed to identify active inhibitors, resulting in a trimer hydroxylated quinone (IIIHyQ) that inhibited NADPH oxidase with an IC(50)=31nM. Apocynin itself possessed minimal inhibitory activity. NADPH oxidase is believed to be inhibited through prevention of the interaction between two NADPH oxidase subunits, p47(phox) and p22(phox). To that end, while apocynin was unable to block the interaction of his-tagged p47(phox) with a surface immobilized biotinylated p22(phox) peptide, the IIIHyQ product strongly interfered with this interaction (apparent IC(50)=1.6microM). These results provide evidence that peroxidase-generated AOP, which consist of oligomeric phenols and quinones, inhibit critical interactions that are involved in the assembly and activation of human vascular NADPH oxidase.

  15. Histochemistry of reactive oxygen-species (ROS)-generating oxidases in cutaneous and mucous epithelia of laboratory rodents with special reference to xanthine oxidase

    NARCIS (Netherlands)

    Gossrau, R.; Frederiks, W. M.; van Noorden, C. J.

    1990-01-01

    Cutaneous and mucous epithelia of various organs of laboratory rodents were analysed histochemically for reactive oxygen species (ROS)-generating oxidases using cerium methods. High activities of xanthine oxidase and also superoxide dismutase were present in orthokeratotic stratified squamous

  16. Targeting lysyl oxidase reduces peritoneal fibrosis.

    Directory of Open Access Journals (Sweden)

    Christopher R Harlow

    Full Text Available Abdominal surgery and disease cause persistent abdominal adhesions, pelvic pain, infertility and occasionally, bowel obstruction. Current treatments are ineffective and the aetiology is unclear, although excessive collagen deposition is a consistent feature. Lysyl oxidase (Lox is a key enzyme required for crosslinking and deposition of insoluble collagen, so we investigated whether targeting Lox might be an approach to reduce abdominal adhesions.Female C57Bl/6 mice were treated intraperitoneally with multiwalled carbon nanotubes (NT to induce fibrosis, together with chemical (ß-aminoproprionitrile-BAPN or miRNA Lox inhibitors, progesterone or dexamethasone. Fibrotic lesions on the diaphragm, and expression of fibrosis-related genes in abdominal wall peritoneal mesothelial cells (PMC were measured. Effects of BAPN and dexamethasone on collagen fibre alignment were observed by TEM. Isolated PMC were cultured with interleukin-1 alpha (IL-1α and progesterone to determine effects on Lox mRNA in vitro.NT-induced fibrosis and collagen deposition on the diaphragm was ameliorated by BAPN, Lox miRNA, or steroids. BAPN and dexamethasone disrupted collagen fibres. NT increased PMC Lox, Col1a1, Col3a1 and Bmp1 mRNA, which was inhibited by steroids. Progesterone significantly inhibited IL-1α induced Lox expression by PMC in vitro.Our results provide proof-of-concept that targeting peritoneal Lox could be an effective approach in ameliorating fibrosis and adhesion development.

  17. Targeting lysyl oxidase reduces peritoneal fibrosis.

    Science.gov (United States)

    Harlow, Christopher R; Wu, Xuan; van Deemter, Marielle; Gardiner, Fiona; Poland, Craig; Green, Rebecca; Sarvi, Sana; Brown, Pamela; Kadler, Karl E; Lu, Yinhui; Mason, J Ian; Critchley, Hilary O D; Hillier, Stephen G

    2017-01-01

    Abdominal surgery and disease cause persistent abdominal adhesions, pelvic pain, infertility and occasionally, bowel obstruction. Current treatments are ineffective and the aetiology is unclear, although excessive collagen deposition is a consistent feature. Lysyl oxidase (Lox) is a key enzyme required for crosslinking and deposition of insoluble collagen, so we investigated whether targeting Lox might be an approach to reduce abdominal adhesions. Female C57Bl/6 mice were treated intraperitoneally with multiwalled carbon nanotubes (NT) to induce fibrosis, together with chemical (ß-aminoproprionitrile-BAPN) or miRNA Lox inhibitors, progesterone or dexamethasone. Fibrotic lesions on the diaphragm, and expression of fibrosis-related genes in abdominal wall peritoneal mesothelial cells (PMC) were measured. Effects of BAPN and dexamethasone on collagen fibre alignment were observed by TEM. Isolated PMC were cultured with interleukin-1 alpha (IL-1α) and progesterone to determine effects on Lox mRNA in vitro. NT-induced fibrosis and collagen deposition on the diaphragm was ameliorated by BAPN, Lox miRNA, or steroids. BAPN and dexamethasone disrupted collagen fibres. NT increased PMC Lox, Col1a1, Col3a1 and Bmp1 mRNA, which was inhibited by steroids. Progesterone significantly inhibited IL-1α induced Lox expression by PMC in vitro. Our results provide proof-of-concept that targeting peritoneal Lox could be an effective approach in ameliorating fibrosis and adhesion development.

  18. Monoamine oxidase inhibitory activities of heterocyclic chalcones.

    Science.gov (United States)

    Minders, Corné; Petzer, Jacobus P; Petzer, Anél; Lourens, Anna C U

    2015-11-15

    Studies have shown that natural and synthetic chalcones (1,3-diphenyl-2-propen-1-ones) possess monoamine oxidase (MAO) inhibition activities. Of particular importance to the present study is a report that a series of furanochalcones acts as MAO-B selective inhibitors. Since the effect of heterocyclic substitution, other than furan (and more recently thiophene, piperidine and quinoline) on the MAO inhibitory properties of the chalcone scaffold remains unexplored, the aim of this study was to synthesise and evaluate further heterocyclic chalcone analogues as inhibitors of the human MAOs. For this purpose, heterocyclic chalcone analogues that incorporate pyrrole, 5-methylthiophene, 5-chlorothiophene and 6-methoxypyridine substitution were examined. Seven of the nine synthesised compounds exhibited IC50 values chalcones are reversible and competitive MAO inhibitors. 4h, however, may exhibit tight-binding to MAO-B, a property linked to its thiophene moiety. We conclude that high potency chalcones such as 4h represent suitable leads for the development of MAO-B inhibitors for the treatment of Parkinson's disease and possibly other neurodegenerative disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Study of Drug Metabolism by Xanthine Oxidase

    Directory of Open Access Journals (Sweden)

    Lizhou Sun

    2012-04-01

    Full Text Available In this work, we report the studies of drug metabolism by xanthine oxidase (XOD with electrochemical techniques. Firstly, a pair of stable, well-defined and quasi-reversible oxidation/reduction peaks is obtained with the formal potential at −413.1 mV (vs. SCE after embedding XOD in salmon sperm DNA membrane on the surface of pyrolytic graphite electrode. Then, a new steady peak can be observed at −730 mV (vs. SCE upon the addition of 6-mercaptopurine (6-MP to the electrochemical system, indicating the metabolism of 6-MP by XOD. Furthermore, the chronoamperometric response shows that the current of the catalytic peak located at −730 mV increases with addition of 6-MP in a concentration-dependent manner, and the increase of the chronoamperometric current can be inhibited by an XOD inhibitor, quercetin. Therefore, our results prove that XOD/DNA modified electrode can be efficiently used to study the metabolism of 6-MP, which may provide a convenient approach for in vitro studies on enzyme-catalyzed drug metabolism.

  20. MONOAMINE OXIDASE: RADIOTRACER DEVELOPMENT AND HUMAN STUDIES.

    Energy Technology Data Exchange (ETDEWEB)

    FOWLER,J.S.; LOGAN,J.; VOLKOW,N.D.; WANG,G.J.; MACGREGOR,R.R.; DING,Y.S.

    2000-09-28

    PET is uniquely capable of providing information on biochemical transformations in the living human body. Although most of the studies of monoamine oxidase (MAO) have focused on measurements in the brain, the role of peripheral MAO as a phase 1 enzyme for the metabolism of drugs and xenobiotics is gaining attention (Strolin Benedetti and Tipton, 1998; Castagnoli et al., 1997.). MAO is well suited for this role because its concentration in organs such as kidneys, liver and digestive organs is high sometimes exceeding that in the brain. Knowledge of the distribution of the MAO subtypes within different organs and different cells is important in determining which substrates (and which drugs and xenobiotics) have access to which MAO subtypes. The highly variable subtype distribution with different species makes human studies even more important. In addition, the deleterious side effects of combining MAO inhibitors with other drugs and with foodstuffs makes it important to know the MAO inhibitory potency of different drugs both in the brain and in peripheral organs (Ulus et al., 2000). Clearly PET can play a role in answering these questions, in drug research and development and in discovering some of the factors which contribute to the highly variable MAO levels in different individuals.

  1. Inhibiting Cholesterol Absorption During Lactation Programs Future Intestinal Absorption of Cholesterol in Adult Mice.

    Science.gov (United States)

    Dimova, Lidiya G; de Boer, Jan Freark; Plantinga, Josee; Plösch, Torsten; Hoekstra, Menno; Verkade, Henkjan J; Tietge, Uwe J F

    2017-08-01

    In nematodes, the intestine senses and integrates early life dietary cues that lead to lifelong epigenetic adaptations to a perceived nutritional environment-it is not clear whether this process occurs in mammals. We aimed to establish a mouse model of reduced dietary cholesterol availability from maternal milk and investigate the consequences of decreased milk cholesterol availability, early in life, on the metabolism of cholesterol in adult mice. We blocked intestinal absorption of cholesterol in milk fed to newborn mice by supplementing the food of dams (for 3 weeks between birth and weaning) with ezetimibe, which is secreted into milk. Ezetimibe interacts with the intestinal cholesterol absorption transporter NPC1l1 to block cholesterol uptake into enterocytes. Characterization of these offspring at 24 weeks of age showed a 27% decrease in cholesterol absorption (P < .001) and reduced levels of Npc1l1 messenger RNA and protein, but not other cholesterol transporters, in the proximal small intestine. We observed increased histone H3K9me3 methylation at positions -423 to -607 of the proximal Npc1l1 promoter in small intestine tissues from 24-week-old offspring fed ezetimibe during lactation, compared with controls. These findings show that the early postnatal mammalian intestine functions as an environmental sensor of nutritional conditions, responding to conditions such as low cholesterol levels by epigenetic modifications of genes. Further studies are needed to determine how decreased sterol absorption for a defined period might activate epigenetic regulators; the findings of our study might have implications for human infant nutrition and understanding and preventing cardiometabolic disease. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  2. Elevated Remnant Cholesterol Causes Both Low-Grade Inflammation and Ischemic Heart Disease, Whereas Elevated Low-Density Lipoprotein Cholesterol Causes Ischemic Heart Disease Without Inflammation

    DEFF Research Database (Denmark)

    Varbo, Anette; Benn, Marianne; Tybjærg-Hansen, Anne

    2013-01-01

    Elevated nonfasting remnant cholesterol and low-density lipoprotein (LDL) cholesterol are causally associated with ischemic heart disease (IHD), but whether elevated nonfasting remnant cholesterol and LDL cholesterol both cause low-grade inflammation is currently unknown.......Elevated nonfasting remnant cholesterol and low-density lipoprotein (LDL) cholesterol are causally associated with ischemic heart disease (IHD), but whether elevated nonfasting remnant cholesterol and LDL cholesterol both cause low-grade inflammation is currently unknown....

  3. Codebook-based interference alignment for uplink MIMO interference channels

    KAUST Repository

    Lee, Hyun Ho

    2014-02-01

    In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multipleoutput (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute the transmit precoder and inform its quantized index to the associated user via limited rate feedback link.We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load tomaintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF. © 2014 KICS.

  4. Partial interference subspace rejection in CDMA systems

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiene; Mewelstein, Paul

    2001-01-01

    Previously presented interference subspace rejection (ISR) proposed a family of new efficient multiuser detectors for CDMA. We reconsider in this paper the modes of ISR using decision feedback (DF). DF modes share similarities with parallel interference cancellation (PIC) but attempt to cancel...... interference by nulling rather than subtraction. However like the PIC they are prone to wrong tentative decisions. We propose a modification to DF modes that performs partial ISR instead of complete interference cancellation. When tentative decisions are correct, interference is therefore not perfectly...

  5. Quantum eraser for three-slit interference

    Science.gov (United States)

    Shah, Naveed Ahmad; Qureshi, Tabish

    2017-12-01

    It is well known that in a two-slit interference experiment, if the information, on which of the two paths the particle followed, is stored in a quantum path detector, the interference is destroyed. However, in a set-up where this path information is `erased', the interference can reappear. Such a set-up is known as a quantum eraser. A generalization of quantum eraser to a `three-slit' interference is theoretically analysed. It is shown that three complementary interference patterns can arise out of the quantum erasing process.

  6. Quantum Interference and Coherence Theory and Experiments

    CERN Document Server

    Ficek, Zbigniew; Rhodes, William T; Asakura, Toshimitsu; Brenner, Karl-Heinz; Hänsch, Theodor W; Kamiya, Takeshi; Krausz, Ferenc; Monemar, Bo; Venghaus, Herbert; Weber, Horst; Weinfurter, Harald

    2005-01-01

    For the first time, this book assembles in a single volume accounts of many phenomena involving quantum interference in optical fields and atomic systems. It provides detailed theoretical treatments and experimental analyses of such phenomena as quantum erasure, quantum lithography, multi-atom entanglement, quantum beats, control of decoherence, phase control of quantum interference, coherent population trapping, electromagnetically induced transparency and absorption, lasing without inversion, subluminal and superluminal light propagation, storage of photons, quantum interference in phase space, interference and diffraction of cold atoms, and interference between Bose-Einstein condensates. This book fills a gap in the literature and will be useful to both experimentalists and theoreticians.

  7. High Cholesterol/Low Cholesterol: Effects in Biological Membranes: A Review.

    Science.gov (United States)

    Subczynski, Witold K; Pasenkiewicz-Gierula, Marta; Widomska, Justyna; Mainali, Laxman; Raguz, Marija

    2017-12-01

    Lipid composition determines membrane properties, and cholesterol plays a major role in this determination as it regulates membrane fluidity and permeability, as well as induces the formation of coexisting phases and domains in the membrane. Biological membranes display a very diverse lipid composition, the lateral organization of which plays a crucial role in regulating a variety of membrane functions. We hypothesize that, during biological evolution, membranes with a particular cholesterol content were selected to perform certain functions in the cells of eukaryotic organisms. In this review, we discuss the major membrane properties induced by cholesterol, and their relationship to certain membrane functions.

  8. IETS and quantum interference: propensity rules in the presence of an interference feature.

    Science.gov (United States)

    Lykkebo, Jacob; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

    2014-09-28

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Second, we consider how inelastic electron tunneling spectroscopy can be used to probe the presence of an interference feature by identifying vibrational modes that are selectively suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference.

  9. INTERFERENCE OF UNIDIRECTIONAL SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-05-01

    Full Text Available Subject of study.We consider interference of unidirectional shock waves or, as they are called, catching up shock waves. The scope of work is to give a classification of the shock-wave structures that arise in this type of interaction of shock waves, and the area of their existence. Intersection of unidirectional shock waves results in arising of a shock-wave structure at the intersection point, which contains the main shock wave, tangential discontinuity and one more reflected gas-dynamic discontinuity of unknown beforehand type. The problem of determining the type of reflected discontinuity is the main problem that one has to solve in the study of catching shock waves interference. Main results.The paper presents the pictures of shock-wave structures arising at the interaction of catching up shock waves. The areas with a regular and irregular unidirectional interaction of shocks are described. Characteristic shock-wave structures are of greatest interest, where reflected gas-dynamic discontinuity degenerates into discontinuous characteristics. Such structures have a number of extreme properties. We have found the areas of existence for such shock-wave structures. There are also areas in which the steady-state solution is not available. The latter has determined revival of interest for the theoretical study of the problem, because the facts of sudden shock-wave structure destruction inside the air intake of supersonic aircrafts at high Mach numbers have been discovered. Practical significance.The theory of interference for unidirectional shock waves and design procedure are usable in the design of supersonic air intakes. It is also relevant for application possibility investigation of catching up oblique shock waves to create overcompressed detonation in perspective detonation air-jet and rocket engines.

  10. Histone deacetylase inhibition decreases cholesterol levels in neuronal cells by modulating key genes in cholesterol synthesis, uptake and efflux.

    Directory of Open Access Journals (Sweden)

    Maria João Nunes

    Full Text Available Cholesterol is an essential component of the central nervous system and increasing evidence suggests an association between brain cholesterol metabolism dysfunction and the onset of neurodegenerative disorders. Interestingly, histone deacetylase inhibitors (HDACi such as trichostatin A (TSA are emerging as promising therapeutic approaches in neurodegenerative diseases, but their effect on brain cholesterol metabolism is poorly understood. We have previously demonstrated that HDACi up-regulate CYP46A1 gene transcription, a key enzyme in neuronal cholesterol homeostasis. In this study, TSA was shown to modulate the transcription of other genes involved in cholesterol metabolism in human neuroblastoma cells, namely by up-regulating genes that control cholesterol efflux and down-regulating genes involved in cholesterol synthesis and uptake, thus leading to an overall decrease in total cholesterol content. Furthermore, co-treatment with the amphipathic drug U18666A that can mimic the intracellular cholesterol accumulation observed in cells of Niemman-Pick type C patients, revealed that TSA can ameliorate the phenotype induced by pathological cholesterol accumulation, by restoring the expression of key genes involved in cholesterol synthesis, uptake and efflux and promoting lysosomal cholesterol redistribution. These results clarify the role of TSA in the modulation of neuronal cholesterol metabolism at the transcriptional level, and emphasize the idea of HDAC inhibition as a promising therapeutic tool in neurodegenerative disorders with impaired cholesterol metabolism.

  11. Embracing interference in wireless systems

    CERN Document Server

    Gollakota, Shyamnath

    2014-01-01

    The wireless medium is a shared resource. If nearby devices transmit at thesame time, their signals interfere, resulting in a collision. In traditionalnetworks, collisions cause the loss of the transmitted information. For thisreason, wireless networks have been designed with the assumption thatinterference is intrinsically harmful and must be avoided.This book, a revised version of the author's award-winning Ph.D.dissertation, takes an alternate approach: Instead of viewing interferenceas an inherently counterproductive phenomenon that should to be avoided, wedesign practical systems that tra

  12. Interference Mitigation in Cognitive Femtocells

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira; Cattoni, Andrea Fabio; Alvarez Roig, Victor

    2010-01-01

    , management and optimization can be prohibitive. Instead, self-optimization of an uncoordinated deployment should be considered. Cognitive Radio enabled femtocells are considered to be a promising solution to enable self-optimizing femtocells to effectively manage the inter-cell interference, especially...... in densely deployed femto scenarios. In this paper, two key elements of cognitive femtocells are combined: a power control algorithm and a fully distributed dynamic spectrum allocation method. The resulting solution was evaluated through system-level simulations and compared to the separate algorithms...

  13. Garbanzo diet lowers cholesterol in hamsters

    Science.gov (United States)

    Cholesterol-lowering potential of diets with 22% protein from Chickpea (Cicer arietinum, European variety of Garbanzo, Kabuli Chana), Bengal gram (Cicer arietinum, Asian variety of Garbanzo, Desi Chana, smaller in size, yellow to black color), lentils, soy protein isolate, hydrolyzed salmon protein...

  14. Cholesterol oxidation products and their biological importance

    Czech Academy of Sciences Publication Activity Database

    Kulig, W.; Cwiklik, Lukasz; Jurkiewicz, Piotr; Rog, T.; Vattulainen, I.

    2016-01-01

    Roč. 199, SI (2016), s. 144-160 ISSN 0009-3084 R&D Projects: GA ČR(CZ) GBP208/12/G016; GA ČR GA15-14292S Institutional support: RVO:61388955 Keywords : cholesterol * oxidation * oxysterols Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.361, year: 2016

  15. Cholesterol levels in fragile X syndrome.

    Science.gov (United States)

    Berry-Kravis, Elizabeth; Levin, Rebecca; Shah, Haroon; Mathur, Shaguna; Darnell, Jennifer C; Ouyang, Bichun

    2015-02-01

    Fragile X syndrome (FXS) is associated with intellectual disability and behavioral dysfunction, including anxiety, ADHD symptoms, and autistic features. Although individuals with FXS are largely considered healthy and lifespan is not thought to be reduced, very little is known about the long-term medical health of adults with FXS and no systematically collected information is available on standard laboratory measures from metabolic screens. During the course of follow up of a large cohort of patients with FXS we noted that many patients had low cholesterol and high density lipoprotein (HDL) values and thus initiated a systematic chart review of all cholesterol values present in charts from a clinic cohort of over 500 patients with FXS. Total cholesterol (TC), low density lipoprotein (LDL) and HDL were all significantly reduced in males from the FXS cohort relative to age-adjusted population normative data. This finding has relevance for health monitoring in individuals with FXS, for treatments with cholesterol-lowering agents that have been proposed to target the underlying CNS disorder in FXS based on work in animal models, and for potential biomarker development in FXS. © 2014 Wiley Periodicals, Inc.

  16. Estimations of cholesterol, triglycerides and fractionation of ...

    African Journals Online (AJOL)

    cholesterol (VLDL-C) in 53 female subjects in Warri, Delta State, Nigeria using the Reflotron® (an auto analyser), supported with the use of questionnaire to get information on age and sex. Age range of the subjects was 18–80 years. The TG levels in ...

  17. globulins and cholesterol levels in Ibadan, Nigeria.

    African Journals Online (AJOL)

    rum total protein, globulin and cholesterol levels were sig- nificantly increased in oral contraceptive and their control counterparts. The albumin/globulin ratio in subjects on oral contraceptives users is significantly decreased compared with controls. In view of the findings of this study, it is suggested that the biochemical ...

  18. Resveratrol protects rabbits against cholesterol diet- induced ...

    African Journals Online (AJOL)

    The excessive consumption of high cholesterol diet has been associated with an increased incidence of lipidaemia. Lipidaemia is enhanced by formation of oxidative stress, lipid peroxidation and hyperglycaemia. The aim of these experiments was to investigate the protective effect of resveratrol co-administered with ...

  19. Blood cholesterol : a public health perspective

    NARCIS (Netherlands)

    Verschuren, W.M.M.

    1995-01-01

    Changes in total cholesterol levels (TC) were studied using data from three epidemiological studies: about 30,000 men and women aged 37-43 were examined between 1974 and 1980 (CB Project), about 80,000 men aged 33-37 between 1981 and 1986 (RIFOH Project) and 42,000 men and women aged 20-59 from 1987

  20. Top Five Lifestyle Changes to Reduce Cholesterol

    Science.gov (United States)

    ... protein is one of two proteins in dairy products — the other is casein. Whey protein may account for many of the health benefits attributed to dairy. Studies have shown that whey protein given as a supplement lowers both LDL and total cholesterol. You can ...

  1. Proximate composition and cholesterol concentrations of ...

    African Journals Online (AJOL)

    Proximate composition and cholesterol concentrations of Rhynchophorus phoenicis and Oryctes monoceros larvae subjected to different heat treatments. ... 514.63 mg/100g dry weight basis (DWB) for raw and fried samples, respectively, but decreased to 295.20 mg/100 g DWB in the smoke-dried samples. Similarly, the ...

  2. Dietary cholesterol increases paraoxonase 1 enzyme activity

    National Research Council Canada - National Science Library

    Kim, Daniel S; Burt, Amber A; Ranchalis, Jane E; Richter, Rebecca J; Marshall, Julieann K; Nakayama, Karen S; Jarvik, Ella R; Eintracht, Jason F; Rosenthal, Elisabeth A; Furlong, Clement E; Jarvik, Gail P

    2012-01-01

    .... Five dietary components, cholesterol (P < 2.0 × 10(-16)), alcohol (P = 8.51 × 10(-8)), vitamin C (P = 7.97 × 10(-5)), iron (P = 0.0026), and folic acid (0.037) were independently predictive of PON1 activity...

  3. Amplified solid-state electrochemiluminescence detection of cholesterol in near-infrared range based on CdTe quantum dots decorated multiwalled carbon nanotubes@reduced graphene oxide nanoribbons.

    Science.gov (United States)

    Huan, Juan; Liu, Qian; Fei, Airong; Qian, Jing; Dong, Xiaoya; Qiu, Baijing; Mao, Hanping; Wang, Kun

    2015-11-15

    An amplified solid-state electrochemiluminescence (ECL) biosensor for detection of cholesterol in near-infrared (NIR) range was constructed based on CdTe quantum dots (QDs) decorated multiwalled carbon nanotubes@reduced graphene nanoribbons (CdTe-MWCNTs@rGONRs), which were prepared by electrostatic interactions. The CdTe QDs decorated on the MWCNTs@rGONRs resulted in the amplified ECL intensity by ~4.5 fold and decreased onset potential by ~100 mV. By immobilization of the cholesterol oxidase (ChOx) and NIR CdTe-MWCNTs@rGONRs on the electrode surface, a solid-state ECL biosensor for cholesterol detection was constructed. When cholesterol was added to the detection solution, the immobilized ChOx catalyzed the oxidation of cholesterol to generate H2O2, which could be used as the co-reactant in the ECL system of CdTe-MWCNTs@rGONRs. The as-prepared biosensor exhibited good performance for cholesterol detection including good reproducibility, selectivity, and acceptable linear range from 1 μM to 1mM with a relative low detection limit of 0.33 μM (S/N=3). The biosensor was successfully applied to the determination of cholesterol in biological fluid and food sample, which would open a new possibility for development of solid-state ECL biosensors with NIR emitters. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Polyamine Oxidase and Diamine Oxidase Activities in Human Milk during the First Month of Lactation.

    Science.gov (United States)

    Bjelakovic, Ljiljana; Kocic, Gordana; Bjelakovic, Bojko; Najman, Stevo; Stojanović, Dusica; Jonovic, Marina; Pop-Trajkovic, Zoran

    2012-06-01

    Human milk (HM) is the ideal food for all newborns and infants. Apart from various bioactive compounds, including cytokines, antibodies, hormones, vitamines, it also contains polyamines, such as spermine (Sp), spermidine (Spd) and putrescine (Put). The present study investigated polyamine metabolism in colostrum and mature human milk by measuring the polyamine oxidase (PAO) and diamine oxidase (DAO) enzyme activities, which are necessary for polyamine catabolism, as well as by determining the malondialdehyde (MDA) levels, the final product of polyamine biodegradation. The PAO, DAO activity and MDA levels were quantified in colostrum (1st and 2nd day) as well as in mature human milk, 30th day of lactation. We found the steady increase of PAO activity and steady decrease of DAO activity and MDA levels during first month of lactation. Since the products of PAO activity such as, amino aldehydes and hydrogen peroxide (H(2)O(2)) might have potential antimicrobial effects, promoting the oxidative stress, it is likely that human milk PAO throughout the lactation period, contributes to the protective effects of human milk.

  5. Compared with Acyl-CoA:cholesterol O-acyltransferase (ACAT) 1 and lecithin:cholesterol acyltransferase, ACAT2 displays the greatest capacity to differentiate cholesterol from sitosterol.

    Science.gov (United States)

    Temel, Ryan E; Gebre, Abraham K; Parks, John S; Rudel, Lawrence L

    2003-11-28

    The capacity of acyl-CoA:cholesterol O-acyltransferase (ACAT) 2 to differentiate cholesterol from the plant sterol, sitosterol, was compared with that of the sterol esterifying enzymes, ACAT1 and lecithin:cholesterol acyltransferase (LCAT). Cholesterol-loaded microsomes from transfected cells containing either ACAT1 or ACAT2 exhibited significantly more ACAT activity than their sitosterol-loaded counterparts. In sitosterol-loaded microsomes, both ACAT1 and ACAT2 were able to esterify sitosterol albeit with lower efficiencies than cholesterol. The mass ratios of cholesterol ester to sitosterol ester formed by ACAT1 and ACAT2 were 1.6 and 7.2, respectively. Compared with ACAT1, ACAT2 selectively esterified cholesterol even when sitosterol was loaded into the microsomes. To further characterize the difference in sterol specificity, ACAT1 and ACAT2 were compared in intact cells loaded with either cholesterol or sitosterol. Despite a lower level of ACAT activity, the ACAT1-expressing cells esterified 4-fold more sitosterol than the ACAT2 cells. The data showed that compared with ACAT1, ACAT2 displayed significantly greater selectively for cholesterol compared with sitosterol. The plasma cholesterol esterification enzyme lecithin:cholesterol acyltransferase was also compared. With recombinant high density lipoprotein particles, the esterification rate of cholesterol by LCAT was only 15% greater than for sitosterol. Thus, LCAT was able to efficiently esterify both cholesterol and sitosterol. In contrast, ACAT2 demonstrated a strong preference for cholesterol rather than sitosterol. This sterol selectivity by ACAT2 may reflect a role in the sorting of dietary sterols during their absorption by the intestine in vivo.

  6. Cytochemical localization of catalase and several hydrogen peroxide-producing oxidases in the nucleoids and matrix of rat liver peroxisomes

    NARCIS (Netherlands)

    Veenhuis, M.; Wendelaar Bonga, S.E.

    1979-01-01

    The distribution of catalase, amino acid oxidase, α-hydroxy acid oxidase, urate oxidase and alcohol oxidase was studied cytochemically in rat hepatocytes. The presence of catalase was demonstrated with the conventional diaminobenzidine technique. Oxidase activities were visualized with methods based

  7. Serum diamine oxidase activity in patients with histamine intolerance.

    Science.gov (United States)

    Manzotti, G; Breda, D; Di Gioacchino, M; Burastero, S E

    2016-03-01

    Intolerance to various foods, excluding bona fide coeliac disease and lactose intolerance, represents a growing cause of patient visits to allergy clinics.Histamine intolerance is a long-known, multifaceted clinical condition triggered by histamine-rich foods and alcohol and/or by drugs that liberate histamine or block diamine oxidase (DAO), the main enzyme involved in the metabolism of ingested histamine. Histamine limitation diets impose complex, non-standardized restrictions that may severely impact the quality of life of patients. We retrospectively evaluated 14 patients who visited allergy outpatient facilities in northern Italy with a negative diagnosis for IgE-mediated food hypersensitivity, coeliac disease, conditions related to gastric hypersecretion, and systemic nickel hypersensitivity, and who previously underwent a histamine limitation diet with benefits for their main symptoms. Serum diamine oxidase levels and the clinical response to diamine oxidase supplementation were investigated. We found that 10 out of 14 patients had serum DAO activityintolerance. Moreover, 13 out of 14 patients subjectively reported a benefit in at least one of the disturbances related to food intolerances following diamine oxidase supplementation. The mean value (±SD) of diamine oxidase activity in the cohort of patients with histamine intolerance symptoms was 7.04±6.90 U/mL compared to 39.50±18.16 U/mL in 34 healthy controls (P=0.0031). In patients with symptoms triggered by histamine-rich food, measuring the serum diamine oxidase activity can help identify subjects who can benefit from a histamine limitation diet and/or diamine oxidase supplementation.Properly designed, controlled studies investigating histamine intolerance that include histamine provocation are indispensable for providing insights into the area of food intolerances, which are currently primarily managed with non-scientific approaches in Italy. © The Author(s) 2015.

  8. Localization of phenol oxidase in female Trichuris suis.

    Science.gov (United States)

    Fetterer, R H; Hill, D E

    1994-12-01

    A phenol oxidase (E.C. 1.10.3.1) preparation from adult female Trichuris suis was assayed by both polarographic and spectrophotometric techniques. The T. suis enzyme oxidized most diphenols including 4-methylcatechol (4MC) and dihydroxyphenylalanine but did not oxidize tyrosine. The pH and temperature optima were 6.8 and 36 C, respectively. The Km measured using 4MC as a substrate ranged from 0.12 to 0.4 mM. The highest phenol oxidase activity was isolated in fractions from the adult females that were enriched in eggs relative to the activity in somatic tissue from females and all male tissues that were assayed. Phenol oxidase activity was localized on sodium dodecyl sulfate-polyacrylamide gel electrophoresis substrate gels into 2 bands with M(r)'s of 44,000 and 53,000. An antibody to the 44,000 band recognized 2 bands of 40,000 and 45,000 M(r) on western blot analysis of the enzyme preparation. Immunocytochemical localization of anti-phenol oxidase antibody in serial cross sections of adult female worms indicates that the enzyme is found exclusively in the anterior part of the parasite in the proximal part of the uterus that is posterior to the junction with the stichosome. Eggs located in more distal parts of the reproductive system did not react with the antibody. The results indicate that a phenol oxidase is located in the fertilized eggs of adult female T. suis. It is likely that phenol oxidase contributes significantly to the chemical hardening process in the eggs when they pass out into the external environment. Inhibition of phenol oxidase may reduce the survivability of the eggs and thus minimize contamination of livestock facilities.

  9. Transbilayer movement and net flux of cholesterol and cholesterol sulfate between liposomal membranes.

    Science.gov (United States)

    Rodrigueza, W V; Wheeler, J J; Klimuk, S K; Kitson, C N; Hope, M J

    1995-05-09

    The kinetics of cholesterol and cholesterol sulfate (CS) movement between vesicles have been investigated. CS is widely distributed in cell membranes, plasma and skin and is similar in structure to cholesterol, but possesses an ionizable sulfate moiety at the 3 beta-position which imparts a negative charge at physiological pHs. Donor vesicles of various sizes ranging from 40 to 250 nm, composed of egg phosphatidylcholine (EPC)/sterol/N-palmitoyldihydrolactosylcerebroside (75:10:15 mole ratio) containing trace amounts of [3H]sterol, were used to monitor sterol transfer into a 10-fold excess of large unilamellar vesicles (LUV) composed of EPC with a diameter of 100 nm. The two populations of vesicles were separated by centrifugation following the addition of a lectin which caused the aggregation of donor vesicles. Both cholesterol and CS exhibited biphasic kinetics of exchange. The rate constants for efflux and transbilayer diffusion for both sterol molecules were determined after fitting kinetic data, using numerical integration, to a three-compartment model, which includes the inner and outer monolayers of donor vesicles and the acceptor bilayer. The rate of intermembrane exchange for CS was approximately 10-fold faster than for cholesterol in all liposomes tested. Using the kinetic model, a rate of transbilayer movement for cholesterol and CS was estimated. In both cases, it was found to be slower than the rate of efflux from the surface of vesicles. For vesicles containing CS, the surface charge was monitored to demonstrate that the slowly exchanging pool was located in the inner monolayer, and the rapidly exchanging pool in the outer half of the bilayer. For cholesterol, it was not possible to distinguish between this model and one where lateral domains of cholesterol within the plane of the bilayer may influence the kinetics of exchange.

  10. Monoamine Oxidase B Inhibitors in Parkinson's Disease.

    Science.gov (United States)

    Dezsi, Livia; Vecsei, Laszlo

    2017-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder with a prevalence increasing with age. Oxidative stress and glutamate toxicity are involved in its pathomechanism. There are still many unmet needs of PD patients, including the alleviation of motor fluctuations and dyskinesias, and the development of therapies with neuroprotective potential. To give an overview of the pharmacological properties, the efficacy and safety of the monoamine oxidase B (MAO-B) inhibitors in the treatment of PD, with special focus on the results of randomized clinical trials. A literature search was conducted in PubMed for 'PD treatment', 'MAO-B inhibitors', 'selegiline', 'rasagiline', 'safinamide' and 'clinical trials' with 'MAO-B inhibitors' in 'Parkinson' disease'. MAO-B inhibitors have a favorable pharmacokinetic profile, improve the dopamine deficient state and may have neuroprotective properties. Safinamide exhibits an anti-glutamatergic effect as well. When applied as monotherapy, MAO-B inhibitors provide a modest, but significant improvement of motor function and delay the need for levodopa. Rasagiline and safinamide were proven safe and effective when added to a dopamine agonist in early PD. As add-on to levodopa, MAO-B inhibitors significantly reduced off-time and were comparable in efficacy to COMT inhibitors. Improvements were achieved as regards certain non-motor symptoms as well. Due to the efficacy shown in clinical trials and their favorable side-effect profile, MAO-B inhibitors are valuable drugs in the treatment of PD. They are recommended as monotherapy in the early stages of the disease and as add-on therapy to levodopa in advanced PD. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Cytochrome C oxidase activity and oxygen tolerance.

    Science.gov (United States)

    Campian, Jian Li; Gao, Xueshan; Qian, Mingwei; Eaton, John W

    2007-04-27

    Most cultured cells and intact animals die under hyperoxic conditions. However, a strain of HeLa cells that proliferates under 80% O(2), termed "HeLa-80," has been derived from wildtype HeLa cells ("HeLa-20") by selection for resistance to stepwise increases of oxygen partial pressure. The tolerance of HeLa-80 cells to hyperoxia is not associated with changes in antioxidant defenses or susceptibility to oxidant-mediated killing. Rather, under both 20 and 80% O(2), mitochondrial reactive oxygen species (ROS) production is approximately 2-fold less in HeLa-80 cells, likely related to a significantly higher cytochrome c oxidase (COX) activity ( approximately 2-fold), which may act to deplete upstream electron-rich intermediates responsible for ROS generation. We now report that in HeLa-80 cells elevated COX activity is associated with a >2-fold increase in the regulatory subunit COX Vb, whereas expression levels of other subunits are very close to wild type. Small interfering RNA against Vb selectively lowers COX Vb expression in HeLa-80 cells, increases mitochondrial ROS generation, decreases COX activity 60-80%, and diminishes viability under 80% (but not 20%) O(2). In addition, overexpression of subunit Vb increases COX activity and decreases ROS production in wild-type HeLa-20 cells, along with some increase in tolerance to hyperoxia. Overall, our results indicate that it is possible to make cells tolerant of hyperoxia by manipulation of mitochondrial electron transport. These observations may suggest new pharmaceutical strategies to diminish oxygen-mediated cellular damage.

  12. Monoamine oxidase and agitation in psychiatric patients.

    Science.gov (United States)

    Nikolac Perkovic, Matea; Svob Strac, Dubravka; Nedic Erjavec, Gordana; Uzun, Suzana; Podobnik, Josip; Kozumplik, Oliver; Vlatkovic, Suzana; Pivac, Nela

    2016-08-01

    Subjects with schizophrenia or conduct disorder display a lifelong pattern of antisocial, aggressive and violent behavior and agitation. Monoamine oxidase (MAO) is an enzyme involved in the degradation of various monoamine neurotransmitters and neuromodulators and therefore has a role in various psychiatric and neurodegenerative disorders and pathological behaviors. Platelet MAO-B activity has been associated with psychopathy- and aggression-related personality traits, while variants of the MAOA and MAOB genes have been associated with diverse clinical phenotypes, including aggressiveness, antisocial problems and violent delinquency. The aim of the study was to evaluate the association of platelet MAO-B activity, MAOB rs1799836 polymorphism and MAOA uVNTR polymorphism with severe agitation in 363 subjects with schizophrenia and conduct disorder. The results demonstrated significant association of severe agitation and smoking, but not diagnosis or age, with platelet MAO-B activity. Higher platelet MAO-B activity was found in subjects with severe agitation compared to non-agitated subjects. Platelet MAO-B activity was not associated with MAOB rs1799836 polymorphism. These results suggested the association between increased platelet MAO-B activity and severe agitation. No significant association was found between severe agitation and MAOA uVNTR or MAOB rs1799836 polymorphism, revealing that these individual polymorphisms in MAO genes are not related to severe agitation in subjects with schizophrenia and conduct disorder. As our study included 363 homogenous Caucasian male subjects, our data showing this negative genetic association will be a useful addition to future meta-analyses. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Lysyl Oxidase Polymorphisms and Susceptibility to Osteosarcoma

    Science.gov (United States)

    He, Zhimin; Zhou, Yujia; Han, Carrie; Shi, Guodong; Gao, Rui; Wang, Ce; Yang, Lili; Song, Haihan; Yuan, Wen

    2012-01-01

    Despite the knowledge of many genetic alterations present in osteosarcoma, the complexity of this disease precludes placing its biology into a simple conceptual framework. Lysyl oxidase (LOX) catalyzes the cross-linking of elastin and collagen, which is essential for the structural integrity and function of bone tissue. In the current study, we performed genomic sequencing on all seven exons -including the intron-exon splice sites, and the putative promoter region of LOX gene - followed by luciferase reporter assay to analyze the function of newly identified polymorphisms. Associations between LOX polymorphisms and osteosarcoma were then evaluated. Our sequencing data revealed three polymorphisms (−22G/C, 225C/G, and 473G/A) in the exons and promoter region of LOX. The −22G/C polymorphism lies in the downstream core promoter element (DPE) region and caused a decrease in promoter activity of LOX. The prevalence of the −22C allele and 473A allele were significantly increased in osteosarcoma patients compared to controls (odds ratio [OR] = 3.88, 95% confidence interval [CI]  = 1.94−7.78, p = 4.18×10−5, and OR = 1.38, 95%CI = 1.07−1.78, p = 0.013; p 0.0167 was considered significant after Bonferroni correction). Analyzing haplotype showed that the frequency of CCG haplotype (−22, 225, 473) was significantly higher in osteosarcoma cases than in healthy controls after Bonferroni correction (p = 4.46×10−4). These results indicate that the −22G/C polymorphism may affect the expression of LOX, and that −22G/C and 473G/A polymorphisms may be new risk factors for osteosarcoma. These findings reveal a potential new pathway by which genetic polymorphisms may affect human diseases. PMID:22911823

  14. Lysyl oxidase polymorphisms and susceptibility to osteosarcoma.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available Despite the knowledge of many genetic alterations present in osteosarcoma, the complexity of this disease precludes placing its biology into a simple conceptual framework. Lysyl oxidase (LOX catalyzes the cross-linking of elastin and collagen, which is essential for the structural integrity and function of bone tissue. In the current study, we performed genomic sequencing on all seven exons--including the intron-exon splice sites, and the putative promoter region of LOX gene--followed by luciferase reporter assay to analyze the function of newly identified polymorphisms. Associations between LOX polymorphisms and osteosarcoma were then evaluated. Our sequencing data revealed three polymorphisms (-22G/C, 225C/G, and 473G/A in the exons and promoter region of LOX. The -22G/C polymorphism lies in the downstream core promoter element (DPE region and caused a decrease in promoter activity of LOX. The prevalence of the -22C allele and 473A allele were significantly increased in osteosarcoma patients compared to controls (odds ratio [OR] = 3.88, 95% confidence interval [CI]= 1.94-7.78, p = 4.18×10(-5, and OR = 1.38, 95%CI = 1.07-1.78, p = 0.013; p 0.0167 was considered significant after Bonferroni correction. Analyzing haplotype showed that the frequency of CCG haplotype (-22, 225, 473 was significantly higher in osteosarcoma cases than in healthy controls after Bonferroni correction (p = 4.46×10(-4. These results indicate that the -22G/C polymorphism may affect the expression of LOX, and that -22G/C and 473G/A polymorphisms may be new risk factors for osteosarcoma. These findings reveal a potential new pathway by which genetic polymorphisms may affect human diseases.

  15. Forage Polyphenol Oxidase and Ruminant Livestock Nutrition

    Directory of Open Access Journals (Sweden)

    Michael Richard F. Lee

    2014-12-01

    Full Text Available Polyphenol oxidase (PPO is associated with the detrimental effect of browning fruit and vegetables, however interest within PPO containing forage crops has grown since the brownng reaction was associated with reduced nitrogen (N losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage increased the quality of protein, improving N-use efficiency (NUE when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalysing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP. If the protein is an enzyme the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase un-degraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of red clover.

  16. The inhibition of monoamine oxidase by esomeprazole.

    Science.gov (United States)

    Petzer, A; Pienaar, A; Petzer, J P

    2013-09-01

    Virtual screening of a library of drugs has suggested that esomeprazole, the S-enantiomer of omeprazole, may possess binding affinities for the active sites of the monoamine oxidase (MAO) A and B enzymes. Based on this finding, the current study examines the MAO inhibitory properties of esomeprazole. Using recombinant human MAO-A and MAO-B, IC50 values for the inhibition of these enzymes by esomeprazole were experimentally determined. To examine the reversibility of MAO inhibition by esomeprazole, the recoveries of the enzymatic activities after dilution of the enzyme-inhibitor complexes were evaluated. In addition, reversibility of inhibition was also examined by measuring the recoveries of enzyme activities after dialysis of enzyme-inhibitor mixtures. Lineweaver-Burk plots were constructed to evaluate the mode of MAO inhibition and to measure Ki values. The results document that esomeprazole inhibits both MAO-A and MAO-B with IC50 values of 23 µM and 48 µM, respectively. The interactions of esomeprazole with MAO-A and MAO-B are reversible and most likely competitive with Ki values for the inhibition of the respective enzymes of 8.99 µM and 31.7 µM. Considering the available pharmacokinetic data and typical therapeutic doses of esomeprazole, these inhibitory potencies are unlikely to be of pharmacological relevance in humans. The MAO inhibitory effects of esomeprazole should however be taken into consideration when using this drug in animal experiments where higher doses are often administered. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Trans Fat Now Listed With Saturated Fat and Cholesterol

    Science.gov (United States)

    ... Trans Fat Now Listed With Saturated Fat and Cholesterol Share Tweet Linkedin Pin it More sharing options ... I Do About Saturated Fat, Trans Fat, and Cholesterol? When comparing foods, look at the Nutrition Facts ...

  18. Short communication Fatty acid and cholesterol content, chemical ...

    African Journals Online (AJOL)

    user

    This study aimed to determine the fatty acid and chemical composition and cholesterol ... It is an essential component of cell membranes and lipoproteins, and a ... present in large quantities, cholesterol may cause cardiovascular diseases, ...

  19. Plasma Ubiquinone, Alpha-Tocopherol and Cholesterol in Man

    DEFF Research Database (Denmark)

    Karlsson, Jan; Diamant, Bertil; Edlund, Per Olof

    1992-01-01

    Farmakologi, Coenzyme Q10, free cholesterol, vitamin E, antioxidants, Alpha-Tocopherol, vitamin Q, plasma, LDL-particle......Farmakologi, Coenzyme Q10, free cholesterol, vitamin E, antioxidants, Alpha-Tocopherol, vitamin Q, plasma, LDL-particle...

  20. Are You Taking the Right Treatment for Your High Cholesterol?

    Science.gov (United States)

    ... You Taking the Right Treatment For Your High Cholesterol? Our analysis and new guidelines could change your ... and 75 years old and have diabetes, high cholesterol, high blood pressure, or if you smoke: • If ...

  1. Remnant cholesterol as a cause of ischemic heart disease

    DEFF Research Database (Denmark)

    Varbo, Anette; Benn, Marianne; Nordestgaard, Børge G

    2014-01-01

    This review focuses on remnant cholesterol as a causal risk factor for ischemic heart disease (IHD), on its definition, measurement, atherogenicity, and levels in high risk patient groups; in addition, present and future pharmacological approaches to lowering remnant cholesterol levels...... are considered. Observational studies show association between elevated levels of remnant cholesterol and increased risk of cardiovascular disease, even when remnant cholesterol levels are defined, measured, or calculated in different ways. In-vitro and animal studies also support the contention that elevated...... levels of remnant cholesterol may cause atherosclerosis same way as elevated levels of low-density lipoprotein (LDL) cholesterol, by cholesterol accumulation in the arterial wall. Genetic studies of variants associated with elevated remnant cholesterol levels show that an increment of 1mmol/L (39mg...

  2. Nonfasting triglycerides, cholesterol, and ischemic stroke in the general population

    DEFF Research Database (Denmark)

    Varbo, Anette; Nordestgaard, Børge G; Tybjaerg-Hansen, Anne

    2011-01-01

    Current guidelines on stroke prevention have recommendations on desirable cholesterol levels, but not on nonfasting triglycerides. We compared stepwise increasing levels of nonfasting triglycerides and cholesterol for their association with risk of ischemic stroke in the general population....

  3. A novel paper-based device coupled with a silver nanoparticle-modified boron-doped diamond electrode for cholesterol detection

    Energy Technology Data Exchange (ETDEWEB)

    Nantaphol, Siriwan [Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330 (Thailand); Chailapakul, Orawon, E-mail: corawon@chula.ac.th [Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330 (Thailand); Center for Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330 (Thailand); Siangproh, Weena, E-mail: weenasi@hotmail.com [Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattanna, Bangkok 10110 (Thailand)

    2015-09-03

    A novel paper-based analytical device (PAD) coupled with a silver nanoparticle-modified boron-doped diamond (AgNP/BDD) electrode was first developed as a cholesterol sensor. The AgNP/BDD electrode was used as working electrode after modification by AgNPs using an electrodeposition method. Wax printing was used to define the hydrophilic and hydrophobic areas on filter paper, and then counter and reference electrodes were fabricated on the hydrophilic area by screen-printing in house. For the amperometric detection, cholesterol and cholesterol oxidase (ChOx) were directly drop-cast onto the hydrophilic area, and H{sub 2}O{sub 2} produced from the enzymatic reaction was monitored. The fabricated device demonstrated a good linearity (0.39 mg dL{sup −1} to 270.69 mg dL{sup −1}), low detection limit (0.25 mg dL{sup −1}), and high sensitivity (49.61 μA mM{sup −1} cm{sup −2}). The precision value for ten replicates was 3.76% RSD for 1 mM H{sub 2}O{sub 2}. In addition, this biosensor exhibited very high selectivity for cholesterol detection and excellent recoveries for bovine serum analysis (in the range of 99.6–100.8%). The results showed that this new sensing platform will be an alternative tool for cholesterol detection in routine diagnosis and offers the advantages of low sample/reagent consumption, low cost, portability, and short analysis time. - Highlights: • Novel PAD coupled with AgNP/BDDE for cholesterol determination was developed. • Wide linear range, low detection limit and high selectivity were achieved. • This sensor was successfully applied for cholesterol determination in bovine serum. • This platform offers the advantages of low sample/reagent consumption and low cost.

  4. Diet-induced dyslipidemia impairs reverse cholesterol transport in hamsters.

    Science.gov (United States)

    Tréguier, Morgan; Briand, François; Boubacar, Adamou; André, Agnès; Magot, Thierry; Nguyen, Patrick; Krempf, Michel; Sulpice, Thierry; Ouguerram, Khadija

    2011-09-01

    Reverse cholesterol transport (RCT) is an anti-atherogenic process by which cholesterol is effluxed from peripheral tissues by high-density lipoprotein (HDL) and returned to the liver for excretion into the bile and faeces. Dyslipidemia is thought to impair RCT through higher triglyceride-rich lipoprotein (TRL), low HDL-cholesterol and higher activity of cholesteryl ester transfer protein (CETP), which transfers cholesteryl esters from HDL to TRL for further hepatic uptake. As CETP pathway would represent a major route in human RCT, we therefore investigated whether diet-induced dyslipidemia impairs RCT in hamster, a CETP-expressing species. Golden Syrian hamsters were fed a chow or chow+0·3% cholesterol diet over 4 weeks. Biochemical parameters and in vivo VLDL-triglycerides secretion (Triton WR-1339 injection) were then measured. In vitro macrophage cholesterol efflux was measured, and in vivo macrophage-to-faeces RCT was also assessed after an intraperitoneal injection of (3) H-cholesterol-labelled hamster primary macrophages. Cholesterol-enriched diet increased plasma total cholesterol (144%), triglycerides (101%), VLDL-triglycerides secretion (175%), CETP activity (44%) and reduced HDL-cholesterol/total cholesterol ratio by 20% (P diet significantly increased hepatic total cholesterol and triglycerides by 459 and 118% and increased aortic total cholesterol content by 304%. In vitro cholesterol efflux from macrophages to plasma was significantly reduced by 25% with plasma from cholesterol-fed hamsters. In vivo RCT experiments showed a significant 75% reduction of macrophage-derived cholesterol faecal excretion in cholesterol-fed hamsters. Overall, these data demonstrate that diet-induced dyslipidemia severely impairs in vivo RCT in hamsters. © 2011 The Authors. European Journal of Clinical Investigation © 2011 Stichting European Society for Clinical Investigation Journal Foundation.

  5. Cholesterol and Copper Affect Learning and Memory in the Rabbit

    OpenAIRE

    Schreurs, Bernard G.

    2013-01-01

    A rabbit model of Alzheimer’s disease based on feeding a cholesterol diet for eight weeks shows sixteen hallmarks of the disease including beta amyloid accumulation and learning and memory changes. Although we have shown that feeding 2% cholesterol and adding copper to the drinking water can retard learning, other studies have shown that feeding dietary cholesterol before learning can improve acquisition and feeding cholesterol after learning can degrade long-term memory. We explore the devel...

  6. Cholesterol in the retina: the best is yet to come

    OpenAIRE

    Pikuleva, Irina A.; Curcio, Christine A.

    2014-01-01

    Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understand...

  7. Non-aqueous capillary electrophoretic separation of cholesterol and 25-hydroxycholesterol after derivatization with Girard P reagent.

    Science.gov (United States)

    Gregus, Michal; Roberg-Larsen, Hanne; Lundanes, Elsa; Foret, Frantisek; Kuban, Petr; Wilson, Steven Ray

    2017-10-01

    Capillary electrophoresis (CE) can provide high separation efficiency with very simple instrumentation, but has yet to be explored regarding oxysterols/cholesterol. Cholesterol and 25-hydroxycholesterol (both are 4-ene-3-ketosteroids) were quantitatively transformed into hydrazones using Girard P reagent after enzymatic oxidation by cholesterol oxidase. Separation was achieved using non-aqueous capillary electrophoresis with UV detection at 280nm; the "charge-tagging" Girard P reagent ensured both charge and chromophore (which are requirements for CE-UV). Excess reagent was also separated from the two analytes, eliminating the need for removal prior to the analysis. The compounds were separated in less than 5min with excellent separation efficiency, using separation electrolytes fully compatible with mass spectrometry. The CE-UV method was used to optimize steps for charge-tagging, revealing that the procedure is affected by the analyte/reagent ratio and reaction time, but also the analyte structure. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. 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.

  9. 25-Hydroxycholesterol Increases the Availability of Cholesterol in Phospholipid Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Brett N.; Schlesinger, Paul H.; Ory, Daniel S.; Baker, Nathan A.

    2011-02-01

    Side-chain oxysterols are enzymatically generated oxidation products of cholesterol that serve a central role in mediating cholesterol homeostasis. Recent work has shown that side-chain oxysterols, such as 25-hydroxycholesterol (25-HC), alter membrane structure in very different ways from cholesterol, suggesting a possible mechanism for how these oxysterols regulate cholesterol homeostasis. Here we extend our previous work, using molecular dynamics simulations of 25-HC and cholesterol mixtures in 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) bilayers to examine interactions between 25-HC and cholesterol in the same bilayer. When added to cholesterol-containing membranes, 25-HC causes larger changes in membrane structure than when added to cholesterol-free membranes, demonstrating interactions between the two sterols. We also find that the presence of 25-HC changes the position, orientation, and solvent accessibility of cholesterol, shifting it into the water interface and therefore its availability to external acceptors. This is consistent with experimental results showing that oxysterols can trigger cholesterol trafficking from the plasma membrane to the endoplasmic reticulum. These interactions provide a potential mechanism for 25-HC-mediated regulation of cholesterol trafficking and homeostasis through direct modulation of cholesterol availability.

  10. Regulation of direct transintestinal cholesterol excretion in mice

    NARCIS (Netherlands)

    van der Velde, Astrid E.; Vrins, Carlos L. J.; van den Oever, Karin; Seemann, Ingar; Elferink, Ronald P. J. Oude; van Eck, Miranda; Kuipers, Folkert; Groen, Albert K.

    2008-01-01

    Biliary secretion is generally considered to be an obligate step in the pathway of excess cholesterol excretion from the body. We have recently shown that an alternative route exists. Direct transintestinal cholesterol efflux ( TICE) contributes significantly to cholesterol removal in mice. Our aim

  11. Sex Differences in the Hepatic Cholesterol Sensing Mechanisms in Mice

    Directory of Open Access Journals (Sweden)

    Ingemar Björkhem

    2013-09-01

    Full Text Available Cholesterol is linked to many multifactorial disorders, including different forms of liver disease where development and severity depend on the sex. We performed a detailed analysis of cholesterol and bile acid synthesis pathways at the level of genes and metabolites combined with the expression studies of hepatic cholesterol uptake and transport in female and male mice fed with a high-fat diet with or without cholesterol. Lack of dietary cholesterol led to a stronger response of the sterol sensing mechanism in females, resulting in higher expression of cholesterogenic genes compared to males. With cholesterol in the diet, the genes were down-regulated in both sexes; however, males maintained a more efficient hepatic metabolic flux through the pathway. Females had higher content of hepatic cholesterol but this was likely not due to diminished excretion but rather due to increased synthesis and absorption. Dietary cholesterol and sex were not important for gallbladder bile acids composition. Neither sex up-regulated Cyp7a1 upon cholesterol loading and there was no compensatory up-regulation of Abcg5 or Abcg8 transporters. On the other hand, females had higher expression of the Ldlr and Cd36 genes. These findings explain sexual dimorphism of cholesterol metabolism in response to dietary cholesterol in a high-fat diet in mice, which contributes to understanding the sex-basis of cholesterol-associated liver diseases.

  12. diagnostic potential of serum vitamin e tocopherol and cholesterol ...

    African Journals Online (AJOL)

    hi-tech

    2003-08-01

    Aug 1, 2003 ... 8 August 2003. DIAGNOSTIC POTENTIAL OF SERUM VITAMIN E TOCOPHEROL AND CHOLESTEROL LEVELS IN CHILDREN WITH PROTEIN ENERGY .... taken as significant. Cholesterol assay of serum: Cholesterol was determined after enzymatic hydrolysis and oxidation of the EDTA-serum samples.

  13. Understanding Lipoproteins as Transporters of Cholesterol and Other Lipids

    Science.gov (United States)

    Biggerstaff, Kyle D.; Wooten, Joshua S.

    2004-01-01

    A clear picture of lipoprotein metabolism is essential for understanding the pathophysiology of atherosclerosis. Many students are taught that low-density lipoprotein-cholesterol is "bad" and high-density lipoprotein-cholesterol is "good." This misconception leads to students thinking that lipoproteins are types of cholesterol rather than…

  14. Immuno-histochemical localization of cholesterol binding proteins in ...

    African Journals Online (AJOL)

    SAM

    2014-07-09

    Jul 9, 2014 ... Positive control tissue sections were stained with Sudan Black-B for microscopic visualization of cholesterol .... 6 cm) by holes made. .... Sudan black-B specially stained the cholesterol droplets in form of black granules, which gave positive binding of cholesterol at appropriate binding sites (Figure 8).

  15. Tuberculosis treatment raises total cholesterol level and restores ...

    African Journals Online (AJOL)

    The aim of this study was to determine whether tuberculosis (TB) treatment normalizes the lipid profile strongly affected by pulmonary TB. Serum levels of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and triglycerides (TG) were determined in 83 patients with ...

  16. Beyond Low-Density Lipoprotein Cholesterol Respective Contributions of Non-High-Density Lipoprotein Cholesterol Levels, Triglycerides, and the Total Cholesterol/High-Density Lipoprotein Cholesterol Ratio to Coronary Heart Disease Risk in Apparently Healthy Men and Women

    NARCIS (Netherlands)

    Arsenault, Benoit J.; Rana, Jamal S.; Stroes, Erik S. G.; Després, Jean-Pierre; Shah, Prediman K.; Kastelein, John J. P.; Wareham, Nicholas J.; Boekholdt, S. Matthijs; Khaw, Kay-Tee

    2009-01-01

    OBJECTIVES: This study was designed to test the hypothesis that at any low-density lipoprotein cholesterol (LDL-C) level, other lipid parameters such as non-high-density lipoprotein cholesterol (HDL-C) levels, triglyceride (TG) levels, and the total cholesterol (TC)/HDL-C are still associated with

  17. Alcohol consumption stimulates early stemps in reverse cholesterol transport

    NARCIS (Netherlands)

    Gaag, van der M.S.; Tol, van A.; Vermunt, S.H.F.; Scheek, L.M.; Schaafsma, G.; Hendriks, H.F.J.

    2001-01-01

    Alcohol consumption is associated with increased HDL cholesterol levels, which may indicate stimulated reverse cholesterol transport. The mechanism is, however, not known. The aim of this study was to evaluate the effects of alcohol consumption on the first two steps of the reverse cholesterol

  18. CHROMATOGRAPHIC METHODS IN THE ANALYSIS OF CHOLESTEROL AND RELATED LIPIDS

    NARCIS (Netherlands)

    HOVING, EB

    1995-01-01

    Methods using thin-layer chromatography, solid-phase extraction, gas chromatography, high-performance liquid chromatography and supercritical fluid chromatography are described for the analysis of single cholesterol, esterified and sulfated cholesterol, and for cholesterol in the context of other

  19. HDL Cholesterol and Risk of Type 2 Diabetes

    DEFF Research Database (Denmark)

    Haase, Christiane L; Tybjærg-Hansen, Anne; Nordestgaard, Børge G

    2015-01-01

    associated with type 2 diabetes is unknown. In a prospective study of the general population (n = 47,627), we tested whether HDL cholesterol-related genetic variants were associated with low HDL cholesterol levels and, in turn, with an increased risk of type 2 diabetes. HDL cholesterol-decreasing gene scores...

  20. Emerging roles of the intestine in control of cholesterol metabolism

    NARCIS (Netherlands)

    Kruit, Janine K.; Groen, Albert K.; van Berkel, Theo J.; Kuipers, Folkert

    2006-01-01

    The liver is considered the major "control center" for maintenance of whole body cholesterol homeostasis. This organ is the main site for de novo cholesterol synthesis, clears cholesterol-containing chylomicron remnants and low density lipoprotein particles from plasma and is the major contributor

  1. Cholesterol Profile of Adults Resident in Eastern Nigeria | Igweh ...

    African Journals Online (AJOL)

    Objective: The present study aims to determine a cholesterol profile for people living in this part of Eastern Nigeria. This will enable recommendation of a range of normal Cholesterol levels for the people living in this part of the world. Method: Total serum cholesterol, HDL, LDL, VLDL and triglycerides levels were determined ...

  2. The treatment of cholesterol: issues, effects and targets

    African Journals Online (AJOL)

    Review: The treatment of cholesterol: issues, effects and targets. 523. Vol 52 No 6. SA Fam Pract 2010. Statins: what are they? Statins are the most powerful cholesterol lowering drugs currently available. Statins inhibit 3-hydroxy-3-methyl- glutaryl-coenzyme A (HMG CoA) reductase, which leads to reduced cholesterol ...

  3. Alcohol consumption stimulates early steps in reverse cholesterol transport

    NARCIS (Netherlands)

    Gaag, M.S. van der; Tol, A. van; Vermunt, S.H.F.; Scheek, L.M.; Schaafsma, G.; Hendriks, H.F.J.

    2001-01-01

    Alcohol consumption is associated with increased HDL cholesterol levels, which may indicate stimulated reverse cholesterol transport. The mechanism is, however, not known. The aim of this study was to evaluate the effects of alcohol consumption on the first two steps of the reverse cholesterol

  4. Diet and lifestyle: its association with cholesterol levels among ...

    African Journals Online (AJOL)

    Dietary patterns, physical activities related with work, habit of consuming liquor were noted while cholesterol level, blood glucose levels, blood pressure, height, weight, waist girth, and hip circumference were measured. Results: The overall prevalence rate of borderline high cholesterol level (200-239) and high cholesterol ...

  5. Moderate alcohol consumption increases cholesterol efflux mediated by ABCA1

    NARCIS (Netherlands)

    Beulens, J.W.J.; Sierksma, A.; Tol, van A.; Fournier, C.

    2004-01-01

    Moderate alcohol consumption increases HDL cholesterol, which is involved in reverse cholesterol transport (RCT). The aim of this study was to investigate the effect of moderate alcohol consumption on cholesterol efflux, using J774 mouse macrophages and Fu5AH cells, and on other parameters in the

  6. Cholesterol-Lowering Supplements: Lower Your Numbers without Prescription Medication

    Science.gov (United States)

    ... fat protein sources May reduce LDL None Whey protein May reduce total cholesterol, LDL cholesterol and triglycerides May cause nausea, constipation, diarrhea or gas Another popular cholesterol-lowering supplement is red yeast rice. There is some evidence that red yeast rice ...

  7. Spatial light interference microscopy (SLIM).

    Science.gov (United States)

    Wang, Zhuo; Millet, Larry; Mir, Mustafa; Ding, Huafeng; Unarunotai, Sakulsuk; Rogers, John; Gillette, Martha U; Popescu, Gabriel

    2011-01-17

    We present spatial light interference microscopy (SLIM) as a new optical microscopy technique, capable of measuring nanoscale structures and dynamics in live cells via interferometry. SLIM combines two classic ideas in light imaging: Zernike's phase contrast microscopy, which renders high contrast intensity images of transparent specimens, and Gabor's holography, where the phase information from the object is recorded. Thus, SLIM reveals the intrinsic contrast of cell structures and, in addition, renders quantitative optical path-length maps across the sample. The resulting topographic accuracy is comparable to that of atomic force microscopy, while the acquisition speed is 1,000 times higher. We illustrate the novel insight into cell dynamics via SLIM by experiments on primary cell cultures from the rat brain. SLIM is implemented as an add-on module to an existing phase contrast microscope, which may prove instrumental in impacting the light microscopy field at a large scale.

  8. CDMA with interference cancellation for multiprobe missions

    Science.gov (United States)

    Divsalar, D.; Simon, M. K.

    1995-01-01

    Code division multiple-access spread spectrum has been proposed for use in future multiprobe/multispacecraft missions. This article considers a general parallel interference-cancellation scheme that significantly reduces the degradation effect of probe (user) interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each probe (user) the total interference produced by the remaining most reliably received probes (users) accessing the channel. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of probe/spacecraft interference. The one-stage interference cancellation was analyzed for two types of tentative decision devices, namely, hard and null zone decisions. Simulation results are given for one- and two-stage interference cancellation for equal as well as unequal received power probes.

  9. Amperometric biosensors for glucose, lactate, and glycolate based on oxidases and redox-modified siloxane polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hale, P.D.; Inagaki, Toru; Lee, Hung Sui; Skotheim, T.A.; Karan, Hiroko I.; Okamoto, Yoshi (Brookhaven National Lab., Upton, NY (USA); Medgar Evers Coll., Brooklyn, NY (USA). Div. of Natural Science and Mathematics; Polytechnic Univ., Brooklyn, NY (USA). Dept. of Chemistry)

    1989-01-01

    Amperometric biosensors based on flavin-containing oxidases undergo several steps which produce a measurable current that is related to the concentration of substrate. In the initial step, the substrate converts the oxidized flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN) into the reduced form (FADH{sub 2} or FMNH{sub 2}). Because these cofactors are located well within the enzyme molecule, direct electron transfer to the surface of a conventional electrode does not occur to a measurable degree. A common method of facilitating this electron transfer is to introduce oxygen into the system because it is the natural acceptor for the oxidases; the oxygen is reduced by the FADH{sub 2} or FMNH{sub 2} to hydrogen peroxide, which can then be detected electrochemically. The major drawback to this approach is the fact that oxidation of hydrogen peroxide requires a large overpotential, thus making these sensors susceptible to interference from electroactive species. To lower the necessary applied potential, several non-physiological redox couples have been employed to shuttle electrons between the flavin moieties and the electrode. For example, sensors based on the ferrocene/ferricinium redox couple and on electrodes consisting of conducting salts such as TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane) have previously been reported. Electron relays have also been attached directly to the enzyme molecule to facilitate electron transfer. More recently, these studies have been extended to include systems where the mediating redox species are covalently attached to polymers such as poly(pyrrole), poly(vinylpyridine), and poly(siloxane). The present paper describes the development of amperometric biosensors based on flavin-containing enzymes and this latter family of polymeric mediators. 9 refs., 5 figs.

  10. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  11. Effect of testosterone deficiency on cholesterol metabolism in pigs fed a high-fat and high-cholesterol diet

    OpenAIRE

    Cai, Zhaowei; Xi, Haitao; Pan, Yongming; Jiang, Xiaoling; Chen, Liang; Cai, Yueqin; Zhu, Keyan; Chen, Cheng; Xu, Xiaoping; Chen, Minli

    2015-01-01

    Background Testosterone deficiency is associated with increased serum cholesterol levels. However, how testosterone deficiency precisely affects cholesterol metabolism remains unclear. Therefore, in the current study, we examined the effect of testosterone deficiency on cholesterol metabolism and liver gene expression in pigs fed a high-fat and high-cholesterol (HFC) diet. Methods Sexually mature male miniature pigs (6?7 months old) were randomly divided into 3 groups as follows: intact male ...

  12. Forage polyphenol oxidase and ruminant livestock nutrition

    Science.gov (United States)

    Lee, Michael R. F.

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated

  13. Forage polyphenol oxidase and ruminant livestock nutrition.

    Science.gov (United States)

    Lee, Michael R F

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated

  14. Potent and selective mediators of cholesterol efflux

    Energy Technology Data Exchange (ETDEWEB)

    Bielicki, John K; Johansson, Jan

    2015-03-24

    The present invention provides a family of non-naturally occurring polypeptides having cholesterol efflux activity that parallels that of full-length apolipoproteins (e.g., Apo AI and Apo E), and having high selectivity for ABAC1 that parallels that of full-length apolipoproteins. The invention also provides compositions comprising such polypeptides, methods of identifying, screening and synthesizing such polypeptides, and methods of treating, preventing or diagnosing diseases and disorders associated with dyslipidemia, hypercholesterolemia and inflammation.

  15. EVALUATION OF SERUM CHOLESTEROL, AMINO TRANSFERASES

    Directory of Open Access Journals (Sweden)

    Anantha Babu

    2016-01-01

    Full Text Available BACKGROUND AND AIMS The purpose of this study was to determine the efficacy of red yeast rice (Monascus purpureus-fermented rice in lowering cholesterol in the blood. At the same time, alanine aminotranferase (ALT, aspartate aminotransferase (AST and gamma-glutamyl transferase (γ-GT were measured for notable side effects in the liver. Possible muscle damage was determined by measuring creatine kinase (CK. METHODS The cholesterol lowering effect in serum of red yeast rice-fed rats were studied over a 42-day feeding period. A total of 16 male Sprague-Dawley rats were randomised into 8 per group: control and treated. Treated rats were administered 1.35g/kg/day. Control rats were maintained on ordinary rat chow. RESULTS Serum cholesterol levels were significantly decreased by 19.13% in treated group compared to controls. This treatment also showed increase in serum ALT and AST activities by 41.90% and 21.53%, respectively. Mean CK activity in treated rats showed an increase by 32.32% when compared with control rats. γ-GT is the only enzyme that showed a decrease of 15.16% in sera of treated rats. Body weights of control and treated rats increased significantly by 10% end of feeding period but were not due to treatment. CONCLUSION Red yeast rice significantly decreased serum cholesterol level at a dosage of 1.35g/kg/day. However, the differences in serum enzyme activities between control and treated rats were not significant.

  16. Electromagnetic Interference (EMI) and TEMPEST Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Electromagnetic Interference (EMI), Electromagnetic Compatibility (EMC) and TEMPEST testing are conducted at EPG's Blacktail Canyon Test Facility in one of its two...

  17. Using Interference to Block RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

    We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag.......We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag....

  18. Evidence for condensed complexes of cholesterol in lipid membranes

    Science.gov (United States)

    Ratajczak, Maria K.

    Although cholesterol is a predominant lipid in the eukaryotic plasma membrane, its interactions with other lipids are still not well understood. Insights into the nature of lipid assembly can be gained from examining lipid-cholesterol interaction using model systems. A key observation was the discovery of liquid-liquid phase diagrams with two critical points in the binary mixtures of cholesterol and lipids. The shape of the phase diagrams can be explained by a thermodynamic model of "condensed complexes". In our quest to characterize cholesterol-lipid interactions, we determined phase diagrams of cholesterol and phospholipids that point to the existence of condensed complexes. This complex formation hypothesis was further supported by experiments involving cholesterol removal by cyclodextrin, grazing x-ray diffraction and x-ray reflectivity studies and isothermal calorimetry. Our study aimed at establishing a correlation (or the lack of) between domain formation and complex formation, as well as determining the mode of cholesterol association with different lipids based on their structural and physical properties. We established a displacement assay by which we were able to probe cholesterol-lipid interactions by perturbing them in the presence of an intercalator that competes with cholesterol for association with lipids. Our data support the condensed complex model between cholesterol and lipids, and cholesterol when complexed with lipids shows low activity whereas free, uncomplexed cholesterol exhibits high activity. We were successful in modulating cholesterol activity by varying the level of intercalator while keeping the cholesterol content fixed. In this thesis, not only have we shown that cholesterol can be displaced by intercalators in model systems, we have further established that such displacement can take place in membranes of live cell.

  19. Cholesterol impairment contributes to neuroserpin aggregation

    Science.gov (United States)

    Giampietro, Costanza; Lionetti, Maria Chiara; Costantini, Giulio; Mutti, Federico; Zapperi, Stefano; La Porta, Caterina A. M.

    2017-03-01

    Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer’s and Parkinson’s diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation.

  20. Fibroblast cholesterol efflux to plasma from metabolic syndrome subjects is not defective despite low high-density lipoprotein cholesterol

    NARCIS (Netherlands)

    Dullaart, Robin P. F.; Groen, Albert K.; Dallinga-Thie, Geesje M.; de Vries, Rindert; Sluiter, Wim J.; van Tol, Arie

    Objective: We tested whether in metabolic syndrome (MetS) subjects the ability of plasma to stimulate cellular cholesterol efflux. an early step in the anti-atherogenic reverse cholesterol transport pathway. is maintained despite low high-density lipoprotein (HDL) cholesterol. Design: In 76 subjects

  1. Fibroblast cholesterol efflux to plasma from metabolic syndrome subjects is not defective despite low high-density lipoprotein cholesterol

    NARCIS (Netherlands)

    Dullaart, Robin P. F.; Groen, Albert K.; Dallinga-Thie, Geesje M.; de Vries, Rindert; Sluiter, Wim J.; van Tol, Arie

    2008-01-01

    OBJECTIVE: We tested whether in metabolic syndrome (MetS) subjects the ability of plasma to stimulate cellular cholesterol efflux, an early step in the anti-atherogenic reverse cholesterol transport pathway, is maintained despite low high-density lipoprotein (HDL) cholesterol. DESIGN: In 76 subjects

  2. Fibroblast cholesterol efflux to plasma from metabolic syndrome subjects is not defective despite low high-density lipoprotein cholesterol

    NARCIS (Netherlands)

    R.P.F. Dullaart (Robin); A. Groen (Albert); G.M. Dallinga-Thie (Geesje); R. de Vries (Rindert); W. Sluiter (Wim); A. van Tol (Arie)

    2008-01-01

    textabstractObjective: We tested whether in metabolic syndrome (MetS) subjects the ability of plasma to stimulate cellular cholesterol efflux, an early step in the anti-atherogenic reverse cholesterol transport pathway, is maintained despite low high-density lipoprotein (HDL) cholesterol. Design: In

  3. Negative interferences by calcium dobesilate in the detection of five serum analytes involving Trinder reaction-based assays.

    Science.gov (United States)

    Guo, Xiuzhi; Hou, Li'an; Yin, Yicong; Wu, Jie; Zhao, Fang; Xia, Liangyu; Cheng, Xinqi; Liu, Qian; Liu, Li; Xu, Ermu; Qiu, Ling

    2018-01-01

    Previously, we reported the strong negative interference of calcium dobesilate, a vasoprotective agent, in creatinine assays involving the Trinder reaction. It is hypothesized that a similar effect occurs in the detection of uric acid (UA), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). The interferences of calcium dobesilate during the detection of the five serum analytes were investigated on automated systems/analysers, and the effects were compared among eight different assay systems for each analyte. A calcium dobesilate standard was added into two sets of the blank serum pools of each analyte at final concentrations of 0, 2, 4, 8, 16, 32, and 64 μg/mL. The percentage deviation of each analyte value was calculated between each drug concentration and the drug-free samples. The clinically acceptable error levels for UA, TC, TG, HDL-C, and LDL-C were defined as ±4.87%, ±4.1%, ±9.57%, ±5.61%, and ±5.46%, respectively. The observed interference was concentration dependent for each analyte. In the presence of 16 μg/mL calcium dobesilate, which was within the therapeutic range, all seven Trinder reaction-based UA assay systems, two TG assay systems, two HDL-C assay systems and one TC assay system exhibited negative drug interferences. Calcium dobesilate negatively interferes with the detection of UA, TG, TC, and HDL-C in assay systems based on the Trinder reaction. The effect was most significant in UA and TG detection.

  4. Fluorescent Probes for Analysis and Imaging of Monoamine Oxidase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dokyoung; Jun, Yong Woong; Ahn, Kyo Han [POSTECH, Pohang (Korea, Republic of)

    2014-05-15

    Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.

  5. Xanthine oxidase inhibitory activity of constituents of Cinnamomum cassia twigs.

    Science.gov (United States)

    Ngoc, Tran Minh; Khoi, Nguyen Minh; Ha, Do Thi; Nhiem, Nguyen Xuan; Tai, Bui Huu; Don, Dao Van; Luong, Hoang Van; Son, Doan Cao; Bae, KiHwan

    2012-07-15

    A methanol extract of the twigs of Cinnamomum cassia was found to inhibit xanthine oxidase. Purification of the methanol extract afforded three new phenolic glycosides, cinnacasolide A-C (11-13), together with 10 known compounds (1-10). The structures of the three new compounds were determined by interpretation of spectroscopic data. Cinnamaldehyde derivatives 1-5 and 7 were significant inhibitors of xanthine oxidase, with IC(50) values ranging from 7.8 to 36.3 μg/mL. The results indicate that the acyl group of these cinnamaldehyde derivatives plays an important role in the inhibition of xanthine oxidase. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Xanthine oxidase in human skeletal muscle following eccentric exercise

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Frandsen, Ulrik; Orthenblad, N.

    1997-01-01

    1. The present study tested the hypothesis that the level of xanthine oxidase is elevated in injured human skeletal muscle in association with inflammatory events. Seven male subjects performed five bouts of strenuous one-legged eccentric exercise. Muscle biopsies from both the exercised...... and the control leg, together with venous blood samples, were obtained prior to exercise and at 45 min, 24, 48 and 96 h after exercise. The time courses of xanthine oxidase immunoreactivity and indicators of muscle damage and inflammation were examined. 2. The number of xanthine oxidase structures observed...... by immunohistological methods in the exercised muscle was up to eightfold higher than control from day 1 to day 4 after exercise (P

  7. Endoscopic Transnasal Approach for Cholesterol Granuloma of the Petrous Apex

    Directory of Open Access Journals (Sweden)

    Mohammad Samadian

    2015-01-01

    Full Text Available Cholesterol granulomas are rare round or ovoid cysts. They contain cholesterol crystals surrounded by foreign bodies of giant cells and are characterized by chronic inflammation. Large cholesterol granuloma can compress surrounding tissue especially cranial nerves. There are several types of surgery for the resection of cholesterol granuloma. We describe 4 cases of cholesterol granuloma operated on via transnasal endoscopic approach. In this report, we describe radiologic and pathologic features of this lesion and explain the advantages and disadvantages of transsphenoidal endoscopic approach for these rare lesions.

  8. Cholesterol monohydrate nucleation in ultrathin films on water

    DEFF Research Database (Denmark)

    Rapaport, H.; Kuzmenko, I.; Lafont, S.

    2001-01-01

    The growth of a cholesterol crystalline phase, three molecular layers thick at the air-water interface, was monitored by grazing incidence x-ray diffraction and x-ray reflectivity. Upon compression, a cholesterol film transforms from a monolayer of trigonal symmetry and low crystallinity...... to the triclinic 3-D crystal structure of cholesterol . H(2)O. By comparison, the cholesterol derivative stigmasterol transforms, upon compression, directly into a crystalline trilayer in the rectangular lattice. These results may contribute to an understanding of the onset of cholesterol crystallization...

  9. Biochemical and Bioimaging Evidence of Cholesterol in Acquired Cholesteatoma

    DEFF Research Database (Denmark)

    Thorsted, Bjarne; Bloksgaard, Maria; Groza, Alexandra

    2016-01-01

    : The results show that the total lipid content of the cholesteatoma matrix is similar to that of stratum corneum from skin and that the cholesteatoma matrix unquestionably contains cholesterol. The cholesterol content in the cholesteatoma matrix is increased by over 30% (w/w dry weight) compared to the control....... The cholesterol sulfate content is below 1% of the total lipids in both the cholesteatoma and the control. Cholesterol ester was reduced by over 30% when compared to the control. CONCLUSIONS: The content of cholesterol in the cholesteatoma matrix is significantly different from that in stratum corneum from skin...

  10. NADPH Oxidases and Their Roles in Skin Homeostasis and Carcinogenesis.

    Science.gov (United States)

    Rudolf, Jana; Raad, Houssam; Taieb, Alain; Rezvani, Hamid Reza

    2017-11-17

    Skin protects the body from dehydration, pathogens, and external mutagens. NADPH oxidases are central components for regulating the cellular redox balance. There is increasing evidence indicating that reactive oxygen species (ROS) generated by members of this enzyme family play important roles in the physiology and pathophysiology of the skin. Recent Advances: NADPH oxidases are active producers of ROS such as superoxide and hydrogen peroxide. Different isoforms are found in virtually all tissues. They play pivotal roles in normal cell homeostasis and in the cellular responses to various stressors. In particular, these enzymes are integral parts of redox-sensitive prosurvival and proapoptotic signaling pathways, in which they act both as effectors and as modulators. However, continuous (re)activation of NADPH oxidases can disturb the redox balance of cells, in the worst-case scenario in a permanent manner. Abnormal NADPH oxidase activity has been associated with a wide spectrum of diseases, as well as with aging and carcinogenesis. Sunlight with its beneficial and deleterious effects induces the activation of NADPH oxidases in the skin. Evidence for the important roles of this enzyme family in skin cancer and skin aging, as well as in many chronic skin diseases, is now emerging. Understanding the precise roles of NADPH oxidases in normal skin homeostasis, in the cellular responses to solar radiation, and during carcinogenesis will pave the way for their validation as therapeutic targets not only for the prevention and treatment of skin cancers but also for many other skin-related disorders. Antioxid. Redox Signal. 00, 000-000.

  11. Effect of Moderate Alcohol Consumption on Parameters of Reverse Cholesterol Transport in Postmenopausal Women

    NARCIS (Netherlands)

    Sierksma, A.; Vermunt, S.H.F.; Lankhuizen, I.M.; Gaag, M.S. van der; Scheek, L.M.; Grobbee, D.E.; Tol, A. van; Hendriks, H.F.J.

    2004-01-01

    Background: Alcohol consumption is associated with increased high-density lipoprotein (HDL) cholesterol levels. One of the main antiatherogenic functions of HDL is reverse cholesterol transport. Three early steps of reverse cholesterol transport are (1) cellular cholesterol efflux, (2) plasma

  12. Partially Purification and Characterization of Polyphenol Oxidase of Quince

    OpenAIRE

    YAĞAR, Hülya; SAĞIROĞLU, Ayten

    2002-01-01

    Polyphenol oxidase (PPO, EC 1.14.18.1) was extracted from quince (Cydonia oblonga) by using 0.1 M phosphate buffer, pH 6.8. The polyphenol oxidase of quince was partially purified by (NH4)2SO4 and dialysis. Substrate specificity experiments were carried out with catechol, pyrogallol, L-DOPA, p-cresole and tyrosine. Catechol was the most suitable substrate compound for quince PPO. The Michaelis constants were 4.54 mM, 7.35mM and 17.8 mM for catechol, pyrogallol and L-DOPA, respective...

  13. A Conserved Steroid Binding Site in Cytochrome c Oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Ling; Mills, Denise A.; Buhrow, Leann; Hiser, Carrie; Ferguson-Miller, Shelagh (Michigan)

    2010-09-02

    Micromolar concentrations of the bile salt deoxycholate are shown to rescue the activity of an inactive mutant, E101A, in the K proton pathway of Rhodobacter sphaeroides cytochrome c oxidase. A crystal structure of the wild-type enzyme reveals, as predicted, deoxycholate bound with its carboxyl group at the entrance of the K path. Since cholate is a known potent inhibitor of bovine oxidase and is seen in a similar position in the bovine structure, the crystallographically defined, conserved steroid binding site could reveal a regulatory site for steroids or structurally related molecules that act on the essential K proton path.

  14. Signal transduction and activation of the NADPH oxidase in eosinophils

    Directory of Open Access Journals (Sweden)

    Mark A Lindsay

    1997-12-01

    Full Text Available Activation of the eosinophil NADPH oxidase and the subsequent release of toxic oxygen radicals has been implicated in the mechanism of parasite killing and inflammation. At present, little is known of the signal transduction pathway that govern agonist-induced activation of the respiratory burst and is the subject of this review. In particular, we focus on the ability of leukotrine B4 to activate the NADPH oxidase in guinea-pig peritoneal eosinophils which can be obtained in sufficient number and purity for detailed biochemical experiments to be performed.

  15. HDL Cholesterol, LDL Cholesterol, and Triglycerides as Risk Factors for CKD: A Mendelian Randomization Study.

    Science.gov (United States)

    Lanktree, Matthew B; Thériault, Sébastien; Walsh, Michael; Paré, Guillaume

    2017-07-26

    High-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglyceride concentrations are heritable risk factors for vascular disease, but their role in the progression of chronic kidney disease (CKD) is unclear. 2-sample Mendelian randomization analysis of data derived from the largest published lipid and CKD studies. Effect of independent genetic variants significantly associated with lipid concentrations was obtained from the Global Lipids Genetics Consortium (n=188,577), and the effect of these same variants on estimated glomerular filtration rate (eGFR), CKD (defined as eGFRGenetics Consortium (n=133,814). Using conventional, multivariable, and Egger Mendelian randomization approaches, we assessed the causal association between genetically determined lipid concentrations and kidney traits. eGFR, dichotomous eGFRGenetically higher triglyceride concentrations appeared associated with higher eGFRs, but this finding was driven by a single pleiotropic variant in the glucokinase regulator gene (GCKR). After exclusion, genetically higher triglyceride concentration was not associated with any kidney trait. Individual patient-level phenotype and genotype information were unavailable. 2-sample Mendelian randomization analysis of data from the largest lipid and CKD cohorts supports genetically higher HDL cholesterol concentration as causally associated with better kidney function. There was no association between genetically altered LDL cholesterol or triglyceride concentration and kidney function. Further analysis of CKD outcomes in HDL cholesterol intervention trials is warranted. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  16. THE REDUCTION OF CHOLESTEROL WITH CUPPING THERAPY ON CHOLESTEROL REDUCTION IN PATIENTS WITH HYPERCHOLESTEROLEMIA

    Directory of Open Access Journals (Sweden)

    Zahid Fikri

    2017-04-01

    Full Text Available Introduction: Hypercholesterolemia is a risk factor causes of death at younger ages. Hypercholesterolemia may increase the risk of atherosclerosis, coronary heart disease, pancreatitis (pancreas inflammation in organs, diabetes mellitus, thyroid disorders, liver disease and kidney disease. Many patients with hypercholesterolemia using cupping therapy. Cupping therapy is alternative treatment process of throwing dirty blood from the body through the skin surface. The objective of this study was to determine the effect of cupping therapy to decrease cholesterol levels in patients with hypercholesterolemia. Method: Design used in this study was quasy experimental design. The population is all patients with hypercholesterolemia in the health center plaza Gresik. The total sample is 18 respondents, taken according to inclusion criteria. Independent variable is the cupping therapy. The dependent variable was the decrease in cholesterol levels. Data were collected using a questionnaire and observation of cholesterol. Data were analyzed using independent t-test and paired t tests with signi fi cance level α < 0.05. Result: The results show that cholesterol levels in patients with hypercholesterolemia treated groups decreased majority. Independent statistical analysis using t-test showed p = 0.001 and with the Paired t-test p value = 0.003. Discussion: This result means that there are significant effects of cupping therapy on cholesterol reduction in patients with hypercholesterolemia aged 45 years and over. Further research needs to be done in control diet, lifestyle and daily activities for the success of cupping therapy.

  17. Microwave assisted direct saponification for the simultaneous determination of cholesterol and cholesterol oxides in shrimp.

    Science.gov (United States)

    Souza, Hugo A L; Mariutti, Lilian R B; Bragagnolo, Neura

    2017-05-01

    A novel microwave-assisted direct saponification method for the simultaneous determination of cholesterol and cholesterol oxides in shrimp was developed and validated. Optimal saponification conditions, determined by means of an experimental design, were achieved using 500mg of sample and 20mL of 1mol/L KOH ethanol solution for 16min at 45°C at maximum power at 200W and magnetic stirring at 120rpm. Higher extraction of cholesterol oxides in a reduced saponification time (∼75 times) was achieved in comparison with the direct cold saponification method. The new method showed low detection (≤0.57μg/mL) and quantification (≤1.73μg/mL) limits, good repeatability (≤10.50% intraday and ≤8.56% interday) and low artifact formation (evaluated by using a deuterated cholesterol-D6 standard). Raw, salted and dried-salted shrimps were successfully analyzed by the validated method. The content of cholesterol oxides increased after salting and decreased after drying. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Effect of honey on serum cholesterol and lipid values.

    Science.gov (United States)

    Münstedt, Karsten; Hoffmann, Sven; Hauenschild, Annette; Bülte, Michael; von Georgi, Richard; Hackethal, Andreas

    2009-06-01

    Small studies have suggested that honey benefits patients with high cholesterol concentrations. The present study aimed to confirm this finding in a larger group of subjects. Sixty volunteers with high cholesterol, stratified according to gender and hydroxymethylglutaryl-coenzyme A reductase inhibitor (statin) treatment (yes/no), were randomized to receive 75 g of honey solution or a honey-comparable sugar solution once daily over a period of 14 days. Baseline measurements, including body mass index (BMI) and lipid profile, were obtained, and subjects also completed dietary questionnaires and the Inventory for the Assessment of Negative Bodily Affect-Trait form (INKA-h) questionnaire. Measurements were repeated 2 weeks later. BMI and high-density lipoprotein (HDL) cholesterol values were significantly correlated (r = -0.487; P cholesterol to HDL cholesterol (r = 0.420; P cholesterol value. INKA-h scores and LDL cholesterol values were also significantly correlated (r = 0.273, P = .042). Neither solution influenced significantly cholesterol or triglyceride values in the total group; in women, however, the LDL cholesterol value increased in the sugar solution subgroup but not in the women taking honey. Although ingesting honey did not reduce LDL cholesterol values in general, women may benefit from substituting honey for sugar in their diet. Reducing the BMI lowers the LDL cholesterol value, and psychological interventions also seem important and merit further investigation.

  19. Cholesterol in the retina: the best is yet to come

    Science.gov (United States)

    Pikuleva, Irina A.; Curcio, Christine A.

    2014-01-01

    Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understanding these genes’ roles in retinal physiology and how chorioretinal cholesterol is maintained. In the first half of this review, we will succinctly summarize physico-chemical properties of cholesterol, its distribution in the human body, general principles of maintenance and metabolism, and differences in cholesterol handling in human and mouse that impact on experimental approaches. This information will provide a backdrop to the second part of the review focusing on unique aspects of chorioretinal cholesterol homeostasis, aging in Bruch's membrane, cholesterol in AMD lesions, a model for lesion biogenesis, a model for macular vulnerability based on vascular biology, and alignment of AMD-related genes and pathobiology using cholesterol and an atherosclerosis-like progression as unifying features. We conclude with recommendations for the most important research steps we can take towards delineating the cholesterol-AMD link. PMID:24704580

  20. Cholesterol in the retina: the best is yet to come.

    Science.gov (United States)

    Pikuleva, Irina A; Curcio, Christine A

    2014-07-01

    Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because of eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understanding these genes' roles in retinal physiology and how chorioretinal cholesterol is maintained. In the first half of this review, we will succinctly summarize physico-chemical properties of cholesterol, its distribution in the human body, general principles of maintenance and metabolism, and differences in cholesterol handling in human and mouse that impact on experimental approaches. This information will provide a backdrop to the second part of the review focusing on unique aspects of chorioretinal cholesterol homeostasis, aging in Bruch's membrane, cholesterol in AMD lesions, a model for lesion biogenesis, a model for macular vulnerability based on vascular biology, and alignment of AMD-related genes and pathobiology using cholesterol and an atherosclerosis-like progression as unifying features. We conclude with recommendations for the most important research steps we can take towards delineating the cholesterol-AMD link. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. HF Interference, Procedures and Tools (Interferences HF, procedures et outils) (CD-ROM)

    National Research Council Canada - National Science Library

    2007-01-01

    ...) on "HF Interference, Procedures and Tools", to address the concerns raised by the potential for unintentional radio interference to be caused by the widespread operation of broadband wire line...

  2. Anticancer Activity of the Cholesterol Exporter ABCA1 Gene

    Directory of Open Access Journals (Sweden)

    Bradley Smith

    2012-09-01

    Full Text Available The ABCA1 protein mediates the transfer of cellular cholesterol across the plasma membrane to apolipoprotein A-I. Loss-of-function mutations in the ABCA1 gene induce Tangier disease and familial hypoalphalipoproteinemia, both cardiovascular conditions characterized by abnormally low levels of serum cholesterol, increased cholesterol in macrophages, and subsequent formation of vascular plaque. Increased intracellular cholesterol levels are also frequently found in cancer cells. Here, we demonstrate anticancer activity of ABCA1 efflux function, which is compromised following inhibition of ABCA1 gene expression by oncogenic mutations or cancer-specific ABCA1 loss-of-function mutations. In concert with elevated cholesterol synthesis found in cancer cells, ABCA1 deficiency allows for increased mitochondrial cholesterol, inhibits release of mitochondrial cell death-promoting molecules, and thus facilitates cancer cell survival, suggesting that elevated mitochondrial cholesterol is essential to the cancer phenotype.

  3. Two X-linked chronic granulomatous disease patients with unusual NADPH oxidase properties

    NARCIS (Netherlands)

    Wolach, Baruch; Broides, Arnon; Zeeli, Tal; Gavrieli, Ronit; de Boer, Martin; van Leeuwen, Karin; Levy, Jacov; Roos, Dirk

    2011-01-01

    Chronic granulomatous disease (CGD) is an immune deficiency syndrome caused by defects in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, the enzyme that generates reactive oxygen species (ROS) in phagocytizing leukocytes. This study evaluates the NADPH oxidase capacity in two

  4. Cloning and sequencing of phenol oxidase 1 (pox1) gene from ...

    African Journals Online (AJOL)

    user

    2011-02-21

    Feb 21, 2011 ... The gene (pox1) encoding a phenol oxidase 1 from Pleurotus ostreatus was sequenced and the corresponding ... codon; pox 1, phenol oxidase 1; DNA, deoxyribonucleic acid;. ORF, opening ...... cytochrome c6. Analysis of ...

  5. Direct Enzymatic Assay for Alcohol Oxidase, Alcohol Dehydrogenase, and Formaldehyde Dehydrogenase in Colonies of Hansenula polymorpha

    OpenAIRE

    Eggeling, L; Sahm, H.

    1980-01-01

    A procedure is described for the qualitative direct identification of alcohol oxidase, alcohol dehydrogenase, and formaldehyde dehydrogenase in yeast colonies. The method has been applied successfully to isolate mutants of Hansenula polymorpha with altered glucose repression of alcohol oxidase.

  6. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    -dynamic discontinuities, the intensities corresponding to the transition from regular to irregular interference were described. Numerical calculations of the shock-wave structure transformation in the conditions of hysteresis were performed. The results were compared with the experiments carried out by hydraulic analogy method. Practical significance. Results of the work complement well the theory of stationary gas-dynamic discontinuities interference and can be used at designing of perspective images of supersonic and hypersonic aircraft.

  7. IETS and quantum interference: propensity rules in the presence of an interference feature

    OpenAIRE

    Lykkebo, Jacob; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C.

    2014-01-01

    Destructive quantum interference in single molecule electronics is an intriguing phe- nomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference ef- fects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Sec- ondly, we consider how inelastic electron tunneling spectroscopy can be used ...

  8. Peroxisomal Polyamine Oxidase and NADPH-Oxidase cross-talk for ROS homeostasis which affects respiration rate in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Efthimios A. Andronis

    2014-04-01

    Full Text Available Homeostasis of reactive oxygen species (ROS in the intracellular compartments is of critical importance as ROS have been linked with nearly all cellular processes and more importantly with diseases and aging. PAs are nitrogenous molecules with an evolutionary conserved role in the regulation of metabolic and energetic status of cells. Recent evidence also suggests that polyamines (PA are major regulators of ROS homeostasis. In Arabidopsis the backconversion of the PAs spermidine (Spd and spermine (Spm to putrescine (Put and Spd, respectively is catalyzed by two peroxisomal PA oxidases (AtPAO. However, the physiological role of this pathway remains largely elusive. Here we explore the role of peroxisomal PA backconversion and in particular that catalyzed by the highly expressed AtPAO3 in the regulation of ROS homeostasis and mitochondrial respiratory burst. Exogenous PAs exert an NADPH-oxidase dependent stimulation of oxygen consumption, with Spd exerting the strongest effect. This increase is attenuated by treatment with the NADPH-oxidase blocker diphenyleneiodonium iodide (DPI. Loss-of-function of AtPAO3 gene results to increased NADPH-oxidase-dependent production of superoxide anions (O2.-, but not H2O2, which activate the mitochondrial alternative oxidase pathway (AOX. On the contrary, overexpression of AtPAO3 results to an increased but balanced production of both H2O2 and O2.-. These results suggest that the ratio of O2.-/H2O2 regulates respiratory chain in mitochondria, with PA-dependent production of O2.- by NADPH-oxidase tilting the balance of electron transfer chain in favor of the AOX pathway. In addition, AtPAO3 seems to be an important component in the regulating module of ROS homeostasis, while a conserved role for PA backconversion and ROS across kingdoms is discussed.

  9. Potential of BODIPY-cholesterol for analysis of cholesterol transport and diffusion in living cells

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Lund, Frederik Wendelboe; Röhrl, Clemens

    2016-01-01

    Cholesterol is an abundant and important lipid component of cellular membranes. Analysis of cholesterol transport and diffusion in living cells is hampered by the technical challenge of designing suitable cholesterol probes which can be detected for example by optical microscopy. One strategy...... and collaborative efforts with Bob Bittman for studying diffusion in the plasma membrane (PM) and uptake of BChol in a quantitative manner. For that purpose, we used a variety of fluorescence approaches including fluorescence correlation spectroscopy and its imaging variants, fluorescence recovery after...... photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP). We also describe pulse-chase studies from the PM using BChol in direct comparison to DHE. Based on the gathered imaging data, we present a two-step kinetic model for sterol transport between PM and recycling endosomes. In addition, we...

  10. Interference and the Law of Energy Conservation

    Science.gov (United States)

    Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

    2014-01-01

    Introductory physics textbooks consider interference to be a process of redistribution of energy from the wave sources in the surrounding space resulting in constructive and destructive interferences. As one can expect, the total energy flux is conserved. However, one case of apparent non-conservation energy attracts great attention. Imagine that…

  11. 47 CFR 74.604 - Interference avoidance.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference avoidance. 74.604 Section 74.604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... Stations § 74.604 Interference avoidance. (a) (b) Where two or more licensees are assigned a common channel...

  12. Mode Interference Effect in Coherent Electron Focusing.

    NARCIS (Netherlands)

    Beenakker, C.W.J.; Houten, H. van; Wees, B.J. van

    1988-01-01

    A novel quantum interference effect in ballistic transport is described: the interference of coherently excited magnetic edge states in a two-dimensional electron gas. The effect explains the characteristic features of the unexpected fine structure observed recently in an electron focusing

  13. Lysyl oxidase-like 4 (LOXL4) promotes proliferation and metastasis of gastric cancer via FAK/Src pathway.

    Science.gov (United States)

    Li, Rong-kun; Zhao, Wen-yi; Fang, Fang; Zhuang, Chun; Zhang, Xiao-xin; Yang, Xiao-mei; Jiang, Shu-heng; Kong, Fan-zhi; Tu, Lin; Zhang, Wen-ming; Yang, Sheng-li; Cao, Hui; Zhang, Zhi-gang

    2015-02-01

    Lysyl oxidase-like 4 (LOXL4) has been found up-regulated in a variety of human malignancies, but its clinical significance and functional roles in gastric cancer (GC) remain unknown. Lysyl oxidase-like 4 (LOXL4) expression level in tumor tissues and human GC cell lines was evaluated by quantitative real-time polymerase chain reaction, Western blotting and immunohistochemical analyses. Its clinical significance was inferred from the analysis of 379 tissue samples of patients with GC using tissue microarray. The roles of LOXL4 in cell proliferation, migration and invasion in vitro were analyzed by gene over-expression, RNA interference and recombinant protein. Effects of LOXL4 on regulation of focal adhesion kinase/Src kinase (FAK/Src) pathway were examined by Western blotting. Lysyl oxidase-like 4 (LOXL4) was up-regulated in GC tissues relative to paired non-tumor tissues, and this over-expression was significantly associated with tumor size, depth of tumor invasion, lymph node metastasis, tumor-node-metastasis (TNM) stages and poorer overall survival. Over-expression of LOXL4 has promotive effects on GC cell proliferation, migration and invasion in vitro, consistent with this, LOXL4 knockdown has inhibitive effects on GC cell proliferation, migration and invasion. Furthermore, recombinant human LOXL4 protein also promoted GC cell proliferation and migration. Subsequent mechanistic studies showed that LOXL4 could activate FAK/Src pathway to enhance cell-extracellular matrix adhesion. Taken together, our data reveal that up-regulation of LOXL4 expression is a frequent event in GC progression, contributes to tumor cell proliferation and metastasis, and LOXL4 may be a potential independent prognostic marker and therapeutic target for GC.

  14. Belief attribution despite verbal interference.

    Science.gov (United States)

    Forgeot d'Arc, Baudouin; Ramus, Franck

    2011-05-01

    False-belief (FB) tasks have been widely used to study the ability of individuals to represent the content of their conspecifics' mental states (theory of mind). However, the cognitive processes involved are still poorly understood, and it remains particularly debated whether language and inner speech are necessary for the attribution of beliefs to other agents. We present a completely nonverbal paradigm consisting of silent animated cartoons in five closely related conditions, systematically teasing apart different aspects of scene analysis and allowing the assessment of the attribution of beliefs, goals, and physical causation. In order to test the role of language in belief attribution, we used verbal shadowing as a dual task to inhibit inner speech. Data on 58 healthy adults indicate that verbal interference decreases overall performance, but has no specific effect on belief attribution. Participants remained able to attribute beliefs despite heavy concurrent demands on their verbal abilities. Our results are most consistent with the hypothesis that belief attribution is independent from inner speech.

  15. Improved CDMA Performance Using Parallel Interference Cancellation

    Science.gov (United States)

    Simon, Marvin; Divsalar, Dariush

    1995-01-01

    This report considers a general parallel interference cancellation scheme that significantly reduces the degradation effect of user interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each user the interference produced by the remaining users accessing the channel in an amount proportional to their reliability. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of user interference. The 1-stage interference cancellation is analyzed for three types of tentative decision devices, namely, hard, null zone, and soft decision, and two types of user power distribution, namely, equal and unequal powers. Simulation results are given for a multitude of different situations, in particular, those cases for which the analysis is too complex.

  16. Interference-exact radiative transfer equation

    DEFF Research Database (Denmark)

    Partanen, Mikko; Haÿrynen, Teppo; Oksanen, Jani

    2017-01-01

    Maxwell's equations with stochastic or quantum optical source terms accounting for the quantum nature of light. We show that both the nonlocal wave and local particle features associated with interference and emission of propagating fields in stratified geometries can be fully captured by local damping...... equation (RTE) as a physically transparent interference-exact model that extends the useful range of computationally efficient and quantum optically accurate interference-aware optical models from simple structures to full optical devices.......The Purcell effect, i.e., the modification of the spontaneous emission rate by optical interference, profoundly affects the light-matter coupling in optical resonators. Fully describing the optical absorption, emission, and interference of light hence conventionally requires combining the full...

  17. A novel interference fringes software counting method

    Science.gov (United States)

    Yang, Yuanzhao; Chen, Benyong; Wu, Xiaowei; Li, Dacheng

    2005-02-01

    Conventional interference fringes counting methods often process two sinusoidal interference signals with a phase difference of π/2 to realize fringe-counting. But when the signals fluctuate in half a period of the signal, the conventional fringe-counting method sometimes produces direction-distinguishing mistakes, then resulting in counting errors. To address the problem, this paper presents a novel interference fringes counting method that uses software to distinguish the forward or backward direction of interference fringe and to count. This fringe-counting method can accurately distinguish the moving direction induced by the fluctuation of interference fringes, so it has the advantages of exact counting, intelligence and reliability. An experimental setup based on a Michelson interferometer is constructed to demonstrate the utility of this fringe-counting method for displacement measurement, and experimental results with a range of 1036mm is presented.

  18. Cytochrome cbb3 of Thioalkalivibrio is a Na+-pumping cytochrome oxidase

    NARCIS (Netherlands)

    Muntyan, M.S.; Cherepanov, D.A.; Malinen, A.M.; Bloch, D.A.; Sorokin, D.Y.; Severina, I.I.; Ivashina, T.V.; Lahti, R.; Muyzer, G.; Skulachev, V.P.

    2015-01-01

    Cytochrome c oxidases (Coxs) are the basic energy transducers in the respiratory chain of the majority of aerobic organisms. Coxs studied to date are redox-driven proton-pumping enzymes belonging to one of three subfamilies: A-, B-, and C-type oxidases. The C-type oxidases (cbb3 cytochromes), which

  19. Molecular mechanisms of irbesartan suppressing atherosclerosis in high cholesterol-diet apolipoprotein E knock-out mice.

    Science.gov (United States)

    Yao, Rui; Cheng, Xiang; Chen, Yong; Xie, Jiang-Jiao; Yu, Xian; Liao, Meng-Yang; Ding, Ying-Jun; Tang, Ting-Ting; Liao, Yu-Hua

    2010-03-04

    Atherosclerosis is a chronic inflammatory disease in which the renin-angiotensin-aldosterone system plays an important role. Evidence indicate that the angiotensin type 1 receptor blockers can suppress atherogenesis, but the exact mechanisms have not been fully elucidated. The study was undertaken to investigate the potential effects and molecular mechanisms of an angiotensin type 1 receptor blocker irbesartan on atherogenesis in high cholesterol-diet apolipoprotein E knock-out mice. Adult male apolipoprotein E knock-out mice were given normal diet or high cholesterol-diet and randomized to receive no treatment or irbesartan 10 mg kg(-1) d(-1) for 12 weeks. The apolipoprotein E knock-out mice with high cholesterol-diet were associated with a marked increase in atherosclerotic lesion area, plasma lipid and angiotensin II levels, as well as the expressions of angiotensin type 1 receptor in the aorta. High cholesterol-diet feeding increases the activity of NADPH oxidase subunits (p47(phox) and Rac), extracellular signal-regulated kinase 1/2, janus kinase 2, signal transducer and activator of transcription 3, nuclear factor-kappaB and the expression of tumor necrosis factor-alpha, interleukin 6, monocyte chemoattactant protein-1 and vascular cell adhesion molecule-1 in the aortas. These changes were suppressed in mice that were treated with irbesartan 10 mg kg(-1) d(-1), with no significant change in systolic blood pressure and plasma lipid levels. The results suggest that irbesartan can attenuate atherosclerosis, and this effect is partly related to the inhibition of oxidative stress and inflammatory signal transduction pathways which eventually leads to the decrease in the expression of inflammatory cytokines. Copyright 2008 Elsevier Ireland Ltd. All rights reserved.

  20. Selective solid-phase extraction of cholesterol using molecularly imprinted polymers and its application in different biological samples.

    Science.gov (United States)

    Shi, Yun; Zhang, Jiang-Hua; Shi, Dan; Jiang, Ming; Zhu, Ye-Xiang; Mei, Su-Rong; Zhou, Yi-Kai; Dai, Kang; Lu, Bin

    2006-11-16

    Non-covalent molecularly imprinted polymers (MIPs) of cholesterol were prepared by UV initiated polymerization. A polymer that had the highest binding selectivity and capability was used as solid-phase extraction (SPE) sorbents for direct extraction of cholesterol from different biological samples (human serum, cow milk, yolk, shrimp, pork and beef). The extraction conditions of molecularly imprinted SPE (MISPE) were optimized and the optimum protocol was: conditioning MISPE cartridges with n-hexane, loading with n-hexane, washing with n-hexane and n-hexane:toluene=9:1, respectively, then eluting with chloroform:ethanol:acetic acid=3:1:1. Cholesterol MISPE selectively recognized, effectively trapped and pre-concentrated cholesterol over a concentration range of 10-80 microg/mL. Recoveries ranged from 80.6% to 92.7%, with R.S.D. lower than 9.8%. Under the optimal condition, MISPE recoveries of spiked human serum, yolk, cow milk, shrimp, pork and beef were 91.1%, 80.4%, 86.6%, 78.2%, 81.4% and 80.1%, respectively. Compared with C18 SPE, almost all of the matrix interferences were removed after MISPE, and better baselines and higher selectivity were achieved.