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Sample records for aminobenzoic acid-ortho

  1. Oxidation of ortho- and para-aminobenzoic acid. A pulse radiolysis- and gamma radiolysis study

    International Nuclear Information System (INIS)

    Solar, Sonja; Getoff, Nikola; Zona, Robert; Solar, Wolfgang

    2011-01-01

    The oxidation of anthranilic acid (ortho-aminobenzoic acid, ANA) and para-aminobenzoic acid (PABA) by · OH, N 3 · and O ·- in basic solution was studied by pulse radiolysis. The kinetic and spectroscopic characteristics of the intermediate transients were determined. For ANA the site attack of the OH radicals was established to be ∼50% on the -NH 2 moiety and ∼50% on the aromatic ring with an overall rate constant k( · OH+ANA)=(5.5x10 9 ) dm 3 mol -1 s -1 . The rate constant of PABA was k( · OH+PABA)=8x10 9 dm 3 mol -1 s -1 . The OH-adducts of both compounds showed a first order decay of 0.8x10 5 and 1.2x10 5 s -1 , respectively, whereby the corresponding anilino-radicals were formed. The rate constant of ANA with solvated electrons was k(e - aq +ANA)=2.9x10 9 dm 3 mol -1 s -1 . The radiation induced decomposition of both substrates was studied by gamma radiolysis as a function of the absorbed dose. They exhibited a distinct radiation resistance, the initial degradation yields were ∼0.16 μmol J -1 , i.e. only 28% of the · OH radicals contributed to their decomposition. The hydroxylation process was of minor importance, the yield of hydroxylated aminobenzoic acids was≤0.01 μmol J -1 .

  2. n-aminobenzoates of rare earths

    International Nuclear Information System (INIS)

    Efremova, G.I.; Buchkova, R.T.; Lapitskaya, A.V.; Pirkes, S.B.

    1977-01-01

    N-aminobenzoates of r.e.e. have been synthesized. Their composition corresponds to the general formula Me(C 6 H 4 NH 2 COO) 3 xnH 2 O, where Me stands for La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; n=1.2. The compounds obtained are identified by chemical analysis and roentgenographically. Their solubility products, which are values of the order of 10 -9 -10 -10 , are determined

  3. Piperazin-1-ium 4-aminobenzoate monohydrate

    Directory of Open Access Journals (Sweden)

    P. Sivakumar

    2016-05-01

    Full Text Available The asymmetric unit of the title hydrated salt, C4H11N2+·C7H6NO2−·H2O, contains a piperazin-1-ium cation, a 4-aminobenzoate anion and a water molecule. One NH group of the piperazine ring is protonated and this ring adopts a chair conformation. The anion of this salt is generated by deprotonation of the OH group of the carboxylic acid substituent of 4-aminobenzoic acid. The benzene ring makes a dihedral angle of 2.6 (2° with the carboxylate substituent. The anion and the solvent water molecule are linked by an N—H...O hydrogen bond. Additional N—H...O and O—H...O hydrogen bonds connect adjacent anions through the water molecules, generating a two-dimensional network parallel to (100, forming R33(12 ring motifs. Adjacent cations are linked by N—H...N hydrogen bonds into infinite chains along (001. These chains are linked to the two-dimensional network of anions and water molecules by another N—H...O hydrogen bond, forming a three-dimensional network.

  4. P - aminobenzoic - 3,5 - T acid

    International Nuclear Information System (INIS)

    Mihaila, V.; Corol, Delia

    1999-01-01

    The p-aminobenzoic acid (PABA) is used in the treatment of rheumatoid arthritis and dermatological diseases. The tritium labelling of PABA leads to the elucidation of essential biomedical aspects concerning the collagen behavior. The process of tritium introduction into the PABA molecule consists of two steps: 1. Bromination of PABA with elemental bromine in 3 and 5 positions; 2. Replacement of bromine with tritium by a substitution catalytic reaction.. PABA - 3,5 - T is purified by thin layer preparative chromatography and is characterized radiochemically by radioactivity measurements carried out by liquid scintillators. The chemical concentration is determined by UV spectrophotometry. The quenching is estimated using a calibration curve of the pure product. The specific activities (about 50-60 Ci/mM) allow very sensitive biomedical studies to be performed. (authors)

  5. Complexing in aqueous solutions of rare earth n-aminobenzoates

    International Nuclear Information System (INIS)

    Efremova, G.I.; Buchkova, R.T.; Lapitskaya, A.V.; Pirkes, S.B.

    1977-01-01

    Complexing in the system ''ion of a rare-earth metal - n-aminobenzoic acid'' has been investigated by the pH-metric method in the pH range of 3.5-5.5. In the La-Eu series, the stability of n-aminobenzoate complexes increases and attains the maximum value in the complex Eu (lg Ksub(st)=2.66). In the Gd-Lu series the stability of the complex particles decreases monotonically

  6. 4-Aza-1-azoniabicyclo?[2.2.2]octa?ne?2-amino?benzoate?2-amino?benzoic acid (1/1/1)

    OpenAIRE

    Arman, Hadi D.; Kaulgud, Trupta; Tiekink, Edward R. T.

    2011-01-01

    A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2+·C7H6NO2−·C7H7NO2. An intramolecular N—H...O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H...O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H...N hydrogen bo...

  7. Aminobenzoates as building blocks for natural product assembly lines.

    Science.gov (United States)

    Walsh, Christopher T; Haynes, Stuart W; Ames, Brian D

    2012-01-01

    The ortho-, meta-, and para- regioisomers of aminobenzoate are building blocks for a wide range of microbial natural products. Both the ortho-isomer (anthranilate) and PABA derive from the central shikimate pathway metabolite chorismate while the meta-isomer is not available by that route and starts from UDP-3-aminoglucose. PABA is largely funnelled into folate biosynthesis while anthranilate is the scaffold for biosynthetic elaboration into many natural heterocycles, most notably with its role in indole formation for tryptophan biosynthesis. Anthranilate is also converted to benzodiazepinones, fumiquinazolines, quinoxalines, phenoxazines, benzoxazolinates, quinolones, and phenazines, often with redox enzyme participation. The 5-hydroxy form of 3-aminobenzaote is the starter unit for ansa-bridged rifamycins, ansamitocins, and geldanamycins, whereas regioisomers 2-hydroxy, 4-hydroxy and 2,4-dihydroxy-3-aminobenzoate are key components of antimycin, grixazone, and platencin and platensimycin biosynthesis, respectively. The enzymatic mechanisms for generation of the aminobenzoate regioisomers and their subsequent utilization for diverse heterocycle and macrocycle construction are examined.

  8. Steric structure and thermodynamic aspects of Dy3+ complexes with aminobenzoic acids in aqueous solutions

    International Nuclear Information System (INIS)

    Kondrashina, Yu.G.; Mustafina, A.R.; Vul'fson, S.G.

    1994-01-01

    Stability and structure of dysprosium(3) aminobenzoate complexes with molar ratios Dy:L 1:1 and 1:2 (HL-aminobenzoic acid) in aqueous solutions are determined on the basis of pH-metric and paramagnetic birefringence data. The increase of conjugation effect in the series of benzoic, meta- ortho-, and para-aminobenzoic acid results in the increase of stability of 1:1 and 1:2 complexes. Features of the structure and coordination of ligands in dysprosium complexes with meta-, ortho-, and para-aminobenzoic acid are considered. 11 refs.; 4 figs.; 2 tabs

  9. Bis(4-aminobenzoic acid-κNdichloridozinc(II

    Directory of Open Access Journals (Sweden)

    Melanie Rademeyer

    2010-12-01

    Full Text Available Molecules of the title compound [ZnCl2(C7H7NO22], are located on a twofold rotation axis. Two 4-aminobenzoic acid moieties, and two chloride ligands are coordinated to a Zn atom in a tetrahedral fashion, forming an isolated molecule. Neighbouring molecules are linked through hydrogen-bonded carboxyl groups, as well as N—H...Cl hydrogen-bonding interactions between amine groups and the chloride ligands of neighbouring molecules, forming a three-dimensional network.

  10. 2-Aminobenzoic acid–4-(pyridin-4-yldisulfanylpyridine (1/1

    Directory of Open Access Journals (Sweden)

    Hadi D. Arman

    2011-12-01

    Full Text Available The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanylpyridine molecule [dihedral angle between the pyridine rings = 89.06 (10°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3°. An N—H...O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O—H...N and N—H...N hydrogen bonds into a supramolecular chain along the b axis. These are connected into layers by π–π interactions occurring between pyridine rings [centroid–centroid distance = 3.8489 (15 Å]. The layers are connected along the a axis by C—H...O contacts. The crystal studied was a racemic twin.

  11. 4-Aminobenzoic acid 4-methylpyridine/4-methylpyridinium 4-aminobenzoate 0.58/0.42: a redetermination from the original data

    Directory of Open Access Journals (Sweden)

    Jan Fábry

    2017-10-01

    Full Text Available The title structure, 4-aminobenzoic acid 4-methylpyridine/4-methylpyridinium 4-aminobenzoate 0.58/0.42, 0.58(C6H7N·C7H7NO2·0.42(C6H8N+·C7H6NO2−, has been redetermined from the data published by Kumar et al. (2015. Acta Cryst. E71, o125-o126. The improvement of the present redetermination consists in the introduction of disorder of the methyl group over two positions as well as in the correction of the positional parameters of the hydrogen atoms that are involved in the O—H...N or N—H...O hydrogen bonds. After the correction, the hydroxyl hydrogen atom turned out to be disordered over two positions about the centre of the O...N bond, which is relatively long [2.642 (2 Å], while the H atoms of the primary amine group account more realistically for the hydrogen-bond pattern after the removal of the positional constraints. All the O—H...N or N—H...O hydrogen bonds which are present in the title structure are of moderate strength.

  12. Physico-chemical studies of some aminobenzoic acid hydrazide complexes

    Directory of Open Access Journals (Sweden)

    S. ABD EL HALEEM

    2004-04-01

    Full Text Available The stability constants and related thermodynamic functions characterizing the formation of divalent Ni, Cu, Zn, Cd and Hg complexes with o- and p-aminobenzoic acid hydrazide were determined potentiometrically at different temperatures. The formations of the complexes are endothermic processes. The formed bonds are mainly electrostatic. Conductometric titration was carried out to determine the stoichiometry and stability of the formed complexes. The structures of complexes were characterized by their IR, 1H-NMR and 13C-NMR spectra, as well as X-ray diffractograms. The coordination process takes place through the carbonyl group and the terminal hydrazinic amino group. The thermal stability of the complexes was followed in the temperature range 20–600ºC.

  13. Complexes of Y, La, and lanthanides with m-aminobenzoic acid

    International Nuclear Information System (INIS)

    Rzaczynska, Z.; Brzyska, W.

    1989-01-01

    m-Aminobenzoates of Y, La and lanthanides prepared in the reaction of the hydroxides of metal with m-aminobenzoic acid in solution have the general formula Ln(m-C 6 H 4 NH 2 COO) 3 .nH 2 O where n = 4 for Ho, Tm, n = 5 for Y, Sm, Dy, Er, Lu, and n = 6 for La, Nd, Eu, Gd, Tb, Yb. The water molecules in the hydrated compounds are in the outer coordination sphere. On heating in air at 350-410K dehydration occurs and anhydrous m-aminobenzoates Ln(m-C 6 H 4 NH 2 COO) 3 are formed. On the basis of the IR spectra it was found that the metal in hydrated m-aminobenzoate of lanthanides is simultaneously coordinated through amino- and carboxyl groups whereas in anhydrous m-aminobenzoates of lanthanides only trough the bidentate carboxyl group. From X-ray analysis it was stated that the hydrated m-aminobenzoates of lanthanides are isostructural in the whole range Y, La-Lu. (Author)

  14. Molecular complex of lumiflavin and 2-aminobenzoic acid: crystal structure, crystal spectra, and solution properties.

    Science.gov (United States)

    Shieh, H S; Ghisla, S; Hanson, L K; Ludwig, M L; Nordman, C E

    1981-08-04

    The molecular complex lumiflavin-2-aminobenzoic acid monohydrate (C13H12N4O2.C7H7NO2.H2O) crystallizes from from aqueous solution as red triclinic prisms. The space group is P1 with cell dimensions a = 9.660 A, b = 14.866 A, c = 7.045 A, alpha = 95.44 degrees , beta = 95.86 degrees, and gamma = 105.66 degrees . The crystal structure was solved by direct methods and refined by block-diagonal least-squares procedures to an R value of 0.050 on the basis of 1338 observed reflections. The structure is composed of stacks of alternating lumiflavin adn un-ionized (neutral) 2-aminobenzoic acid molecules. Two different modes of stacking interaction are observed. In one, 2-aminobenzoic acid overlaps all three of the isoalloxazine rings, at a mean distance of 3.36 A; in the other, 2-aminobenzoic acid interacts distance of 3.36 A; in the other, 2-aminobenzoic acid interacts with the pyrazine and dimethylbenzene moieties, at a distance of 3.42 A. Perpendicular to the stacking direction, the molecules form a continuous sheet. Each flavin is hydrogen bonded via O(2) and NH(3) to two symmetrically related aminobenzoates; the water of crystallization forms three hydrogen bonds, bridging two flavins, via O(4) and N(5), and one aminobenzoic acid. The red color of the crystals results from a charge-transfer transition involving stacked flavin and 2-aminobenzoic acid. The red color of the crystals results from a charge-transfer transition involving stacked flavin and 2-aminobenzoic acid molecules. Measurements of the polarized optical absorption spectra of crystals show that the transition moment direction for the long wavelength absorbance (beyond 530 nm) contains an out-of-plane component which can only arise from a charge-transfer interaction. Since the amino N does not make exceptionally close interactions with isoalloxazine atoms in either stacking mode (minimum interatomic distance 3.52 A), the charge transfer is presumed to involve pi orbitals of the 2-aminobenzoic acid donor.

  15. Complexes of heavy lanthanides with o-aminobenzoic acid

    International Nuclear Information System (INIS)

    Brzyska, W.; Rzaczynska, Z.

    1988-01-01

    Anthranilates of Tb-Lu prepared in the reaction of the rare earth hydroxides with ortho-aminobenzoic acid (anthranilic acid) have the general formula Ln(C 6 H 4 NH 2 COO) 3 centredot 2H 2 O where Ln = Tb, Dy, Ho, Er, Tm, Yb, Lu. The water molecules in the hydrated compounds are in the outer coordination sphere. On heating in air at 493 K dehydration occurs and the anhydrous anthranilates Ln(C 6 H 4 NH 2 COO) 3 are formed. On the basis of the IR spectra it was found that the metal in dihydrated anthranilates was simultaneously coordinated through amino and carboxyl groups whereas in anhydrous anthranilates only through the bidentate carboxyl group. From X-ray analysis it was stated that the anthranilates Ln(C 6 H 4 NH 2 COO) 3 centredot 2H 2 O are isostructural, whereas the anhydrous compounds Ln(C 6 H 4 NH 2 COO) 3 are isostructural in the two groups Tb-Er and Tm-Lu. (Author)

  16. Investigation into rare earth n-aminobenzoates by thermography and IR spectroscopy

    International Nuclear Information System (INIS)

    Efremova, G.I.; Buchkova, R.T.; Lapitskaya, A.V.; Pirkes, S.B.

    1977-01-01

    N-aminobenzoates of r.e.e. of the composition of M(C 6 H 4 NH 2 COO) 3 x nH 2 O have been studied by thermography and infrared spectroscopy (M=La,Ce,Pr,Nd,Sm,Eu,Cd,TdHo,Er, Tm,Yb,Lu; n=1,2). It has been established that thermal decomposition of crystallohydrates of r.e.e. n-aminobenzoates is accompanied by the formation as intermediates of non-aqueous r.e.e. n-aminobenzoates stable within a rather wide temperature range (200-300 deg). The final products of thermolysis are oxides of the corresponding r.e.e. The assignment is given of the main absorption bands in infrared spectra of n-aminobenzoates of r.e.e. The assumptions have been made about their nature: crystallization water in crystallohydrates is outward of the sphere and connected with the ligand aminogroup; the metal is, evidently, not coordinated with the nitrogen of the aminogroup. n-aminobenzoate ion is a bidentate ligand

  17. Studies on the complexes of uranium(IV), thorium(IV) and lanthanum(III) acetates with p-aminobenzoic acid, m-aminobenzoic acid, benzilic acid and phthalic acid

    International Nuclear Information System (INIS)

    Singh, Mangal; Singh, Ajaib

    1979-01-01

    Complexes of acetates of U(IV), Th(IV) and La(III) with the ligands p-aminobenzoic acid, m-aminobenzoic acid, benzilic acid and phthalic acid have been prepared. Colour and chemical analytical data are recorded. They are characterised on the basis of IR and reflectance spectra and magnetic susceptibility data. (M.G.B.)

  18. Complexing of zirconium and hafnium with ortho-aminobenzoic acid and paraaminobenzoic acid

    International Nuclear Information System (INIS)

    Alekseeva, I.I.; Nemzer, I.I.; Yuranova, L.I.; Borisova, V.V.; Prozorovskaya, Z.N.

    1977-01-01

    Formation of complexes between zirconium and hafnium and ortho- and para-aminobenzoic acids has been studied by the kinetic method. It has been found that at pH=1.3-2.0 and concentrations of metals 10 -5 -10 -6 mole complex compounds are formed with composition Me:L=1:2 and 1:1 (Me=Zr, Hf; L=ortho- or para-aminobenzoic acids). Stepwise constants and overall effective constants of complex formation have been calculated

  19. 2-Aminobenzoic acid–4-(pyridin-4-yldisulfanyl)pyridine (1/1)

    OpenAIRE

    Hadi D. Arman; Trupta Kaulgud; Edward R. T. Tiekink

    2011-01-01

    The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanyl)pyridine molecule [dihedral angle between the pyridine rings = 89.06 (10)°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3)°. An N—H...O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O&#...

  20. Synthesis and physicochemical investigation of 3-nitro-5-aminobenzoates of rare earths

    International Nuclear Information System (INIS)

    Makushova, G.N.; Zakharova, T.V.; Shilova, L.I.

    1994-01-01

    The compounds of cerium subgroup rare earth with 3-nitro-5-aminobenzoic acid of composition Ln(C 7 H 5 N 2 O 4 ) 3 ·nH 2 O, where Ln-La, Ce, Pr, Nd, Sm, Eu; n=4-14 not yet described in literature were obtained. Rare earth 3-nitro-5-aminobenzoates were individual crystal substances, as shown by X-ray diffraction; their interplanar distances were calculated. Thermal stability of the derived compounds was studied by means of thermography and thermal gravimetry. The interval of dehydration and start of decomposition of anhydrous salts was determined

  1. Characterization of the role of para-aminobenzoic acid biosynthesis in folate production by Lactococcus lactis

    NARCIS (Netherlands)

    Wegkamp, H.B.A.; Oorschot, van A.; Vos, de W.M.; Smid, E.J.

    2007-01-01

    The pab genes for para-aminobenzoic acid (pABA) biosynthesis in Lactococcus lactis were identified and characterized. In L. lactis NZ9000, only two of the three genes needed for pABA production were initially found. No gene coding for 4-amino-4-deoxychorismate lyase (pabC) was initially annotated,

  2. Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

    Indian Academy of Sciences (India)

    Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

  3. Synthesis, thermal, spectral, and biological properties of zinc(II) 4-aminobenzoate complexes

    Czech Academy of Sciences Publication Activity Database

    Homzová, K.; Györyová, K.; Hudecová, D.; Koman, M.; Melník, M.; Kovářová, Jana

    2017-01-01

    Roč. 129, č. 2 (2017), s. 1065-1082 ISSN 1388-6150 Institutional support: RVO:61389013 Keywords : zinc(II) 4-aminobenzoate * thermal * spectral Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.953, year: 2016

  4. Effects of para-aminobenzoic acid (PABA) form and administration mode on PABA recovery in 24-hour urine collections.

    Science.gov (United States)

    Sharma, Rashmi S; Joy, Raechel C; Boushey, Carol J; Ferruzzi, Mario G; Leonov, Alexei P; McCrory, Megan A

    2014-03-01

    Para-aminobenzoic acid (PABA) has long been used as an objective measure to assess completeness of 24-hour urine collections. However, pharmaceutical-grade PABA for human ingestion is not available in the United States. An alternative, the potassium salt of PABA, aminobenzoate potassium, can be obtained for clinical use, although it has not yet been validated in this role. Both PABA and aminobenzoate potassium can be directly ingested in their tablet or capsule forms or added to food before consumption. Our aim was to investigate the effect of form (PABA vs aminobenzoate potassium) and administration mode (directly ingested as a tablet/capsule vs added to food) on urinary PABA recovery levels. Twenty healthy participants underwent 3 test days separated by two 24-hour wash-out periods. Three test conditions, one on each test day, were investigated in randomized order: PABA tablet, aminobenzoate potassium capsule, and PABA or aminobenzoate potassium in food. Ingestion of each dose was supervised and participants performed the 24-hour urine collections while free-living. The 24-hour urine collections were analyzed for PABA recovery (%R) levels using a colorimetric assay. Recoveries 85% to 110% were deemed complete and those >110% were reanalyzed by high pressure liquid chromatography and mass spectrometry. Only complete collections (>85%R) were included in analyses. The recovery for the PABA tablet, aminobenzoate potassium capsule, and PABA/aminobenzoate potassium in food were similar at 98.8%R±2.0%R, 95.1%R±2.3%R, and 93.2%R±2.1%R, respectively, and did not differ significantly. These results suggest that aminobenzoate potassium may be used as an alternative to PABA for assessing the completeness of 24-hour urine collections and to track compliance with consuming provided diets in community-dwelling studies. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  5. Thermodynamic study of phase transitions in methyl esters of ortho- meta- and para-aminobenzoic acids

    International Nuclear Information System (INIS)

    Almeida, Ana R.R.P.; Monte, Manuel J.S.

    2012-01-01

    Highlights: ► Vapor pressures of liquid and crystalline phases of methyl esters of the aminobenzoic acids were measured. ► Accurate values of enthalpies of sublimation, vaporization, and fusion were derived. ► The enthalpy of intermolecular NH–O hydrogen bonds in methyl p-aminobenzoate was determined. ► The volatility of the methyl benzoates was compared with the volatility of the parent acids. - Abstract: A static method based on capacitance gauges was used to measure the vapor pressures of the condensed phases of the methyl esters of the three aminobenzoic acids. For methyl o-aminobenzoate the vapor pressures of the liquid phase were measured in the range (285.4 to 369.5) K. For the meta and para isomers vapor pressures of both crystalline and liquid phases were measured in the ranges (308.9 to 376.6) K, and (332.9 to 428.0) K, respectively. Vapor pressures of the latter compound were also measured using the Knudsen effusion method in the temperature range (319.1 to 341.2) K. From the dependence of the vapor pressures on the temperature, the standard molar enthalpies and entropies of sublimation and of vaporization were derived. Differential scanning calorimetry was used to measure the temperatures and molar enthalpies of fusion of the three isomers. The results enabled the estimation of the enthalpy of the intermolecular (N−H … O) hydrogen bond in the crystalline methyl p-aminobenzoate. A correlation relating the temperature of fusion and the enthalpy and Gibbs energy of sublimation of benzene, methyl benzoates and benzoic acids was derived.

  6. 4-Aza-1-azoniabicyclo[2.2.2]octane–2-aminobenzoate–2-aminobenzoic acid (1/1/1

    Directory of Open Access Journals (Sweden)

    Hadi D. Arman

    2011-11-01

    Full Text Available A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2+·C7H6NO2−·C7H7NO2. An intramolecular N—H...O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H...O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H...N hydrogen bond to the unprotonated amino N atom in the cation. In this way, a three-component aggregate is formed. These are connected into a three-dimensional network by amino–carboxylate N—H...O hydrogen bonds. N—H...N hydrogen bonds are also observed.

  7. Thermal and spectroscopic study to investigate p-aminobenzoic acid, sodium p-aminobenzoate and its compounds with some lighter trivalent lanthanides

    International Nuclear Information System (INIS)

    Teixeira, J.A.; Nunes, W.D.G.; Colman, T.A.D.; Nascimento, A.L.C.S do; Caires, F.J.; Campos, F.X.; Gálico, D.A.; Ionashiro, M.

    2016-01-01

    Highlights: • The p-aminobenzoic acid melts followed partial evaporation. • The stoichiometry of compounds was established by TG, EA and complexometry. • The TG–DTA curves provided previously unreported information about thermal behavior. - Abstract: The characterization, thermal stability and thermal decomposition of some lighter trivalent lanthanide p-aminobenzoates, Ln(C 7 H 6 NO 2 ) 3 ·H 2 O (Ln = La, Ce, Pr, Nd, Sm), as well as the thermal behavior and spectroscopic study of p-aminobenzoic acid C 7 H 7 NO 2 and its sodium salt were investigated. The following methods were utilized: simultaneous thermogravimetry and differential thermal analysis (TG–DTA) in dynamic dry air and nitrogen atmospheres; differential scanning calorimetry (DSC); middle (MIR) and near (NIR) infrared region spectroscopy; evolved gas analysis (EGA); elemental analysis; complexometry; X-ray diffraction (XRD); and diffuse reflectance spectroscopy (DR) in the ultraviolet and visible regions. All the compounds were obtained monohydrated and the thermal decomposition occurred in two, three or four steps in an air atmosphere, and three or four steps in N 2 atmosphere. In both atmospheres (air and N 2 ) the final residues were CeO 2 , Pr 6 O 11 , Ln 2 O 3 (Ln = La, Nd, Sm). The results also provided information concerning the coordination mode and thermal behavior, as well as the identification of the gaseous products which evolved during the thermal decomposition of these compounds. The DR and NIR spectra provided information about the ligand absorption bands and the f–f transitions of the Nd 3+ , Pr 3+ and Sm 3+ ions.

  8. Thermal and spectroscopic study to investigate p-aminobenzoic acid, sodium p-aminobenzoate and its compounds with some lighter trivalent lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, J.A.; Nunes, W.D.G.; Colman, T.A.D.; Nascimento, A.L.C.S do [Instituto de Química, UNESP—Universidade Estadual Paulista, Campus Araraquara, Departamento de Química Analítica, Araraquara 14801-970, SP (Brazil); Caires, F.J. [Faculdade de Ciências, UNESP—Universidade Estadual Paulista, Campus Bauru, Departamento de Química, Bauru 17033-260, SP (Brazil); Campos, F.X. [Instituto de Química, UNESP—Universidade Estadual Paulista, Campus Araraquara, Departamento de Química Analítica, Araraquara 14801-970, SP (Brazil); Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso, Primavera do Leste 78850-000, MT (Brazil); Gálico, D.A. [Instituto de Química, UNICAMP—Universidade Estadual de Campinas, Campinas 13083-970, SP (Brazil); Ionashiro, M., E-mail: massaoi@yahoo.com.br [Instituto de Química, UNESP—Universidade Estadual Paulista, Campus Araraquara, Departamento de Química Analítica, Araraquara 14801-970, SP (Brazil)

    2016-01-20

    Highlights: • The p-aminobenzoic acid melts followed partial evaporation. • The stoichiometry of compounds was established by TG, EA and complexometry. • The TG–DTA curves provided previously unreported information about thermal behavior. - Abstract: The characterization, thermal stability and thermal decomposition of some lighter trivalent lanthanide p-aminobenzoates, Ln(C{sub 7}H{sub 6}NO{sub 2}){sub 3}·H{sub 2}O (Ln = La, Ce, Pr, Nd, Sm), as well as the thermal behavior and spectroscopic study of p-aminobenzoic acid C{sub 7}H{sub 7}NO{sub 2} and its sodium salt were investigated. The following methods were utilized: simultaneous thermogravimetry and differential thermal analysis (TG–DTA) in dynamic dry air and nitrogen atmospheres; differential scanning calorimetry (DSC); middle (MIR) and near (NIR) infrared region spectroscopy; evolved gas analysis (EGA); elemental analysis; complexometry; X-ray diffraction (XRD); and diffuse reflectance spectroscopy (DR) in the ultraviolet and visible regions. All the compounds were obtained monohydrated and the thermal decomposition occurred in two, three or four steps in an air atmosphere, and three or four steps in N{sub 2} atmosphere. In both atmospheres (air and N{sub 2}) the final residues were CeO{sub 2}, Pr{sub 6}O{sub 11}, Ln{sub 2}O{sub 3} (Ln = La, Nd, Sm). The results also provided information concerning the coordination mode and thermal behavior, as well as the identification of the gaseous products which evolved during the thermal decomposition of these compounds. The DR and NIR spectra provided information about the ligand absorption bands and the f–f transitions of the Nd{sup 3+}, Pr{sup 3+} and Sm{sup 3+} ions.

  9. Sensitive determination of buformin using poly-aminobenzoic acid modified glassy carbon electrode

    Directory of Open Access Journals (Sweden)

    Gui-Ying Jin

    2012-12-01

    Full Text Available Glassy carbon electrode, which is used to electrochemically determine the content of buformin, is modified with an electropolymerized film of p-aminobenzoic acid in pH 7.0 acetate buffer solution (ABS. The polymer showed an excellent electrocatalytic activity for the reduction of buformin. In pH 7.0 ABS, the cathodic peak current increased linearly over three concentration intervals of buformin, and the detection limit (S/N=3 was 2.0×10−9 g/mL. The method was successfully applied to directly determine buformin in tablets with standard addition recoveries of 95.8–102.5%. The proposed method is simple, cheap and highly efficient. Keywords: Chemically modified electrode, Aminobenzoic acid, Buformin

  10. Ester Sensing with Poly (Aniline-co-m-aminobenzoic Acid Deposited on Poly (Vinyl Alcohol

    Directory of Open Access Journals (Sweden)

    S. ADHIKARI

    2011-02-01

    Full Text Available Poly (aniline-co-m-aminobenzoic acid was deposited on poly (vinyl alcohol film by in situ oxidative polymerization of the monomers aniline and m-aminobenzoic acid. Sensing experiments were performed on the composite film with the injection of various concentrations of hexenyl acetate and hexenyl butyrate at room temperature. The sensor responded rapidly and reversibly in the presence of hexenyl acetate and hexenyl butyrate vapors which was detected by resistance change of the composite film upon exposure to the vapor. Selectivity tests revealed that the sensor selectively responded to hexenyl butyrate compared to hexenyl acetate. The sensing response has been explained on the basis of FT-IR spectroscopic analysis of the polymer film before and after exposure to the ester vapor.

  11. Determination of monosaccharides derivatized with 2-aminobenzoic Acid by capillary electrophoresis.

    Science.gov (United States)

    Abo, Mitsuru; He, Li-Ping; Sato, Kae; Okubo, Akira

    2013-01-01

    Reducing monosaccharides were derivatized with 2-aminobenzoic acid (2-AA) through reductive amination using sodium cyanoborohydride as a reductant, and the derivatives were separated by capillary zone electrophoresis with UV detection using 50 mM sodium phosphate (pH 5.5) or 150 mM sodium borate-50 mM sodium phosphate (pH 7.0) running buffer. The derivatives of monosaccharides, which are major components of various carbohydrate materials, were completely separated within 25 min.

  12. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Cursino, Ana Cristina Trindade, E-mail: anacursino@ufpr.br [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil); Rives, Vicente, E-mail: vrives@usal.es [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx [Universidad de Guadalajara, Department of Chemistry, Boulevard Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Trujillano, Raquel, E-mail: rakel@usal.es [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Wypych, Fernando, E-mail: wypych@ufpr.br [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil)

    2015-10-15

    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.

  13. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    International Nuclear Information System (INIS)

    Cursino, Ana Cristina Trindade; Rives, Vicente; Arizaga, Gregorio Guadalupe Carbajal; Trujillano, Raquel; Wypych, Fernando

    2015-01-01

    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials

  14. Aryl- and heteroaryl-substituted aminobenzo[a]quinolizines as dipeptidyl peptidase IV inhibitors.

    Science.gov (United States)

    Boehringer, Markus; Fischer, Holger; Hennig, Michael; Hunziker, Daniel; Huwyler, Joerg; Kuhn, Bernd; Loeffler, Bernd M; Luebbers, Thomas; Mattei, Patrizio; Narquizian, Robert; Sebokova, Elena; Sprecher, Urs; Wessel, Hans Peter

    2010-02-01

    Synthesis and SAR are described for a structurally distinct class of DPP-IV inhibitors based on aminobenzo[a]quinolizines bearing (hetero-)aromatic substituents in the S1 specificity pocket. The m-(fluoromethyl)-phenyl derivative (S,S,S)-2g possesses the best fit in the S1 pocket. However, (S,S,S)-2i, bearing a more hydrophilic 5-methyl-pyridin-2-yl residue as substituent for the S1 pocket, displays excellent in vivo activity and superior drug-like properties. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  15. 4-Aminobenzoic acid–1,2-bis(4-pyridylethane (2/1

    Directory of Open Access Journals (Sweden)

    Fwu Ming Shen

    2010-07-01

    Full Text Available In the title compound, C12H12N2·2C7H7NO2, the 4-aminobenzoic acid molecules are linked by O—H...N hydrogen bonds to 1,2-bis(4-pyridylethane, forming linear hydrogen bonded chains parallel to [2overline{1}1]. The structure exhibits a hydrogen-bonding network involving COOH...N(pyridyl and amine and carboxylic N—H... O interactions. In addition, π–π stacking interactions [centroid–centroid distance = 3.8622 (14 Å] are also present.

  16. Photophysics and Photochemistry of 2-Aminobenzoic Acid Anion in Aqueous Solution

    Science.gov (United States)

    Pozdnyakov, Ivan P.; Plyusnin, Victor F.; Grivin, Vjacheslav P.

    2009-11-01

    Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA-) in aqueous solutions. Excitation of this species gives rise to the ABA- triplet state to the ABA• radical and to the hydrated electron (eaq-). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA- triplet state, the ABA• radical, and eaq- are T-T annihilation, recombination, and capture by the ABA- anion, respectively.

  17. Separation of 2-aminobenzoic acid-derivatized glycosaminoglycans and asparagine-linked glycans by capillary electrophoresis.

    Science.gov (United States)

    Sato, Kae; Sato, Kiichi; Okubo, Akira; Yamazaki, Sunao

    2005-01-01

    A capillary electrophoresis method was developed for the analysis of oligosaccharides combined with derivatization with 2-aminobenzoic acid. Glycosaminoglycan delta-disaccharides were effectively resolved on a fused-silica capillary tube using 150 mM borate, pH 8.5, as a running electrolyte solution. This analytical method was applied to the identification of glycosaminoglycan in combination with enzymatic digestion. The separation of N-glycans or glucose-oligomers was performed with a phosphate buffer containing polyethylene glycol or borate as an electrolyte solution. This method is expected to be useful in the determination of oligosaccharide structures in a glycoprotein.

  18. Detection of chitinase activity by 2-aminobenzoic acid labeling of chito-oligosaccharides.

    Science.gov (United States)

    Ghauharali-van der Vlugt, Karen; Bussink, Anton P; Groener, Johanna E M; Boot, Rolf G; Aerts, Johannes M F G

    2009-01-01

    Chitinases are hydrolases capable of hydrolyzing the abundant natural polysaccharide chitin. Next to artificial fluorescent substrates, more physiological chito-oligomers are commonly used in chitinase assays. Analysis of chito-oligosaccharides products is generally accomplished by UV detection. However, the relatively poor sensitivity poses a serious limitation. Here we report on a novel, much more sensitive assay for the detection of chito-oligosaccharide reaction products released by chitinases, based on fluorescent detection, following chemical labeling by 2-aminobenzoic acid. Comparison with existing UV-based assays, shows that the novel assay offers the same advantages yet allows detection of chito-oligosaccharides in the low picomolar range.

  19. X-raying investigation into complexes of n-aminobenzoic acid with metals

    International Nuclear Information System (INIS)

    Amiraslanov, I.R.; Mamedov, Kh.S.; Movsumov, Eh.M.; Musaev, F.N.; Magerramov, A.I.; Nadzhafov, G.N.; AN Azerbajdzhanskoj SSR, Baku. Inst. Fiziki)

    1979-01-01

    The X-ray structural study of triaqua-bis(p-aminobenzoate) of cadmium(2)Cd(H 2 NC 6 H 4 COO) 2 x3H 2 O is carried out. The crystals are triclinic. The coordination number of cadmium atom is 7, it forms two chelate cycles with two carboxylate ligands, and in axial positions is coordinated by nitrogen atoms of aminogroups of the two neighbouring complexes, forming a polymeric chain. Coordination is added up to 7 by one water molecule, which together with other water molecules not entering in the coordination sphere, sew together polymeric chains by hydrogen bonds

  20. The use of the 2-aminobenzoic acid tag for oligosaccharide gel electrophoresis.

    Science.gov (United States)

    Huang, Z; Prickett, T; Potts, M; Helm, R F

    2000-08-18

    Gel electrophoresis of fluorophore labeled saccharides provides a rapid and reliable method to screen enzymatic and/or chemical treatments of polysaccharides and glycoconjugates, as well as a sensitive and efficient microscale method to separate and purify oligosaccharides for further analysis. A simple and inexpensive method of derivatization and analysis using 2-aminobenzoic acid (anthranilic acid, AA) is described and applied to the extracellular polysaccharide released by the desiccation tolerant cyanobacterium Nostoc commune DRH-1. The results of these analyses suggest a possible protective functionality of two pendent groups, as well as a potential relationship between these groups and the desiccation tolerance of the organism.

  1. Spectroscopic and structural studies on some divalent metal salt of p-aminobenzoic acid (ABA(MG)) tetracyanonickelate complexes

    International Nuclear Information System (INIS)

    Atalay, Y.

    2004-01-01

    Infrared spectra of MLNi (CN) 4 [ M=Mn, Fe, Co, Ni, Zn or Cd and LDivalent metal salt of p- Aminobenzoic Acid or ABA (Mg) ] are reported. Their structure consists of polymeric layers of [M-Ni(CN) 4 ] α with the divalent metal salt of p-aminobenzoic acid [ABA(Mg)] molecules bound directly to the metal (M). These spectra were comparewith powder the Xray diffraction pattern of complexes. It is show that proposed structures for these complexes derived from Mattson 1000 FTIR spectra are consistent with the X-ray powder diffraction measurements and elemental analysis result

  2. Solution thermodynamics of pyrazinamide, isoniazid, and p-aminobenzoic acid in buffers and octanol

    International Nuclear Information System (INIS)

    Blokhina, Svetlana V.; Ol’khovich, Marina V.; Sharapova, Angelica V.; Volkova, Tatyana V.; Perlovich, German L.

    2015-01-01

    Highlights: • Solubility of pyrazinamide, isoniazid, p-aminobenzoic acid were measured. • The activity coefficients of the compounds at infinite dilution were determined. • Thermodynamic functions of dissolution and solvation were calculated. - Abstract: The solubility values of pyrazinamide, isoniazid, and p-aminobenzoic acid in buffers (pH 2.0 and 7.4) and octanol were measured in the temperature range of 293.15 to 313.15 K. The dissolution Gibbs energy, enthalpy, and entropy were calculated. The dissolving process was endothermic and enthalpy-determined. The activity coefficients of the compounds at infinite dilution were determined based on the solubility data and thermophysical parameters. A positive deviation from the ideality was observed in all the solutions. A common tendency of the solubility increase with a decrease in the activity coefficients at T = 298.15 K was revealed for the investigated solute-solvent systems. The excess thermodynamic solubility functions were calculated from the temperature dependences of the activity coefficients. The solvation processes were found to have a considerable influence on the solubility of the substances in solutions studied.

  3. Synthesis and antibacterial activity of some Schiff bases derived from 4-aminobenzoic acid

    Directory of Open Access Journals (Sweden)

    JIGNA PAREKH

    2005-10-01

    Full Text Available The following Schiff bases have been synthesized: (1 4-[(2-chlorobenzylidene amino]benzoic acid [JP1], (2 4-[(furan-2-ylmethyleneamino]benzoic acid [JP2], (3 4-[(3-phenylallylideneamino]benzoic acid [JP3], (4 4-[(2-hydroxybenzylidene amino]benzoic acid [JP4], (5 4-[(4-hydroxy-3-methoxybenzylideneamino]benzoic acid [JP5] and (6 4-[(3-nitrobenzylideneamino]benzoic acid [JP6]. They were screened as potential antibacterial agents against a number of medically important bacterial strains. The antibacterial activity was studied against A. faecalis ATCC 8750, E. aerogenes ATCC 13048, E. coli ATCC 25922, K. pneumoniae NCIM 2719, S. aureus ATCC 25923, P. vulgaris NCIM 8313, P. aeruginosa ATCC 27853 and S. typhimurium ATCC 23564. The antibacterial activity was evaluated using the Agar Ditch method. The solvents used were 1,4-dioxane and dimethyl sulfoxide. Different effects of the compounds were found in the bacterial strains investigated and the solvents used, suggesting, once again, that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. In the present work, 1,4-dioxane proved to be a good solvent in inhibiting the above stated bacterial strains.

  4. Synthesis, crystal structure and biological activity of 2-hydroxyethylammonium salt of p-aminobenzoic acid.

    Directory of Open Access Journals (Sweden)

    Manuela E Crisan

    Full Text Available p-Aminobenzoic acid (pABA plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA. The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surface area, docking experiments, Molecular Dynamics and Quantum Mechanics/Molecular Mechanics calculations. The docking study of the folate precursor pABA, its anionic form and natural auxin (indole-3-acetic acid, IAA with the auxin receptor TIR1 revealed a similar binding mode in the active site. The phytotoxic evaluation of HEA-pABA, pABA and 2-hydroxyethylamine (HEA was performed on the model plant Arabidopsis thaliana ecotype Col 0 at five different concentrations. HEA-pABA and pABA acted as potential auxin-like regulators of root development in Arabidopsis thaliana (0.1 and 0.2 mM and displayed an agravitropic root response at high concentration (2 mM. This study suggests that HEA-pABA and pABA might be considered as potential new regulators of plant growth.

  5. Solvation and Aggregation of Meta-Aminobenzoic Acid in Water: Density Functional Theory and Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Etienne Gaines

    2018-01-01

    Full Text Available Meta-aminobenzoic acid, an important model system in the study of polymorphism and crystallization of active pharmaceutical ingredients, exist in water in both the nonionic (mABA and zwitterionic (mABA± forms. However, the constituent molecules of the polymorph that crystallizes from aqueous solutions are zwitterionic. This study reports atomistic simulations of the events surrounding the early stage of crystal nucleation of meta-aminobenzoic acid from aqueous solutions. Ab initio molecular dynamics was used to simulate the hydration of mABA± and mABA and to quantify the interaction of these molecules with the surrounding water molecules. Density functional theory calculations were conducted to determine the low-lying energy conformers of meta-aminobenzoic acid dimers and to compute the Gibbs free energies in water of nonionic, (mABA2, zwitterionic, (mABA±2, and nonionic-zwitterionic, (mABA(mABA±, species. Classical molecular dynamics simulations of mixed mABA–mABA± aqueous solutions were carried out to examine the aggregation of meta-aminobenzoic acid. According to these simulations, the selective crystallization of the polymorphs whose constituent molecules are zwitterionic is driven by the formation of zwitterionic dimers in solution, which are thermodynamically more stable than (mABA2 and (mABA(mABA± pairs. This work represents a paradigm of the role of molecular processes during the early stages of crystal nucleation in affecting polymorph selection during crystallization from solution.

  6. Synthesis, purification and characterization of [3,5 - T] p-aminobenzoic acid

    International Nuclear Information System (INIS)

    Corol-Cucu, Delia-Irina; Chiper, Diana; Mihaila, V.; Negoita, N.

    2000-01-01

    This paper refers to the synthesis, purification and characterization of [3,5-T] p-aminobenzoic acid (PAB,H' vitamine). The p-aminobenzoic acid is used in the treatment of rheumatic arthritis and dermatological affections. The advantage of tritium labelling of p-aminobenzoic acid is that some biomedical important aspects of collagen's behaviour are made clear. The PAB stimulate the grow of intestinal bacteria so necessary to synthesis of some vitamins (bio tine, pantothenic acid). Tritium is the only radioactive isotope of hydrogen. Several steps have to be carried out in the synthesis of the final product as well as to study its biological behavior. For the labelling of PAB one prefers the substitution of bromine from PAB-3,5-Br with tritium because of simplicity of reaction and the easy synthesis of halogen compound. The first step in synthesis is the protection of NH 2 group through acetylation of PAB. After that PAB is bromated into the 3 and 5 position with elementary bromine. The raw compound is purified and recrystallized and characterized through thin layer chromatography.The tritium labelling is performed through substitution of bromine from bromate derivative, using Pd/C (10% Pd) as catalyst and low basic conditions for the neutralization of HBr resulting from reaction. After the separation of PAB-3,5-T through filtration, the catalyst remains on the filter paper and the labelled compound goes in aqueous solution. PAB-3,5-T is purified through thin layer chromatography with the solvent system n-BuOH:NH 4 OH(25%):H 2 O:EtOH (8:1:2:2,5, v/v) with silica gel GF 254 as support. The determination of activity is carried out with LSC (Liquid Scintillation Counter). A 98% purity was determined through TLC in the same conditions while determination of activity distribution was performed with a 2π Berthold scanner with gas running and without window. The chemical concentration has been measured through UV spectrophotometry and by comparing extinction with

  7. Molecular Complex of Lumiflavin and 2-Aminobenzoic Acid : Crystal Structure, Crystal Spectra, and Solution Properties

    OpenAIRE

    Shieh, Huey-Sheng; Ghisla, Sandro; Hanson, Louise Karle; Ludwig, Martha L.; Nordman, Christer E.

    1981-01-01

    The molecular complex lumiflavin-2-aminobenzoic acid monohydrate (C13H12N402●C7H7N02●H2O)crystallizes from aqueous solution as red triclinic prisms. The space group is P1 with cell dimensions a = 9.660 A, b = 14.866 Å, c = 7.045 Å, α = 95.44°, β = 95.86°, and γ = 105.66°. The crystal structure was solved by direct methods and refined by block-diagonal least-squares procedures to an R value of 0.050 on the basis of 1338 observed reflections. The structure is composed of stacks of alternating l...

  8. P-aminobenzoic acid and tritiated cyanoborohydride for the detection of pyruvoyl residues in proteins

    International Nuclear Information System (INIS)

    van Poelje, P.D.; Snell, E.E.

    1987-01-01

    A procedure for the detection of covalently bound pyruvic acid in purified proteins or in crude extracts is described. The dialyzed sample is first treated with sodium cyanoborohydride to reduce any Schiff bases present and then incubated with p-aminobenzoic acid and sodium [ 3 H]cyanoborohydride. Derivatized proteins are visualized by fluorography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel slices containing the labeled proteins are hydrolyzed, and, after removal of polyacrylic acid, the hydrolysate is subjected to ion-exchange high-performance liquid chromatography. The presence of pyruvic acid is established by the detection of a tritiated, 280-nm absorbing compound with a retention time corresponding to that of synthetic N-(p-carboxyphenyl)alanine. The procedure is capable of detecting protein-bound pyruvic acid in the picomolar range and is easily modified to screen for other covalently bound keto acids

  9. 4-Aminobenzoic acid–4,4′-(propane-1,3-diyldipyridine (1/1

    Directory of Open Access Journals (Sweden)

    Fwu Ming Shen

    2010-11-01

    Full Text Available In the crystal structure of the title compound, C13H14N2·C7H7NO2, the 4,4′-trimethylene-dipyridine (TMDP molecule displays an approximately planar structure, the maximum atomic deviation excluding H atoms being 0.118 (2 Å and the dihedral angle between the pyridine rings 4.59 (10°. The TMDP and 4-aminobenzoic acid (ABA molecules are linked by O—H...N and N—H...N hydrogen bonding, while ABA molecules are linked by O—H...O hydrogen bonding. C—H...π interactions are also observed between the methylene groups of TMDP molecules and the benzene rings of ABA molecules.

  10. A spectrophotometric determination of cyanate using reaction with 2-aminobenzoic acid.

    Science.gov (United States)

    Guilloton, M; Karst, F

    1985-09-01

    A specific method has been devised for the assay of cyanate, based on the reaction with 2-aminobenzoic acid. Cyclization of the product in 6 N HCl results in the formation of 2,4(1H,3H)-quinazolinedione. Cyanate content of the samples can be measured by their absorbances at 310 nm. Alternatively, the second derivatives of the spectra can be recorded; the peak-to-peak height between the first maximum (330 nm) and the first minimum (317 nm) was shown to be proportional to the cyanate content. This method is suitable for the estimation of cyanate in aqueous solutions in the concentration range 0.01 to 2 mM. When added to blood plasma, cyanate could be detected down to 0.1 mM.

  11. SEPARATION OF p-AMINOBENZOIC ACID BY REACTIVE EXTRACTION. 1. MECHANISM AND INFLUENCING FACTORS

    Directory of Open Access Journals (Sweden)

    DAN CASCAVAL

    2008-09-01

    Full Text Available The comparative study on the reactive extraction of p-aminobenzoic acid with Amberlite LA-2 and D2EHPA in two solvents with different polarity (n-heptane and dichloromethane indicated that the extractant type and solvent polarity control the extraction mechanism. Thus, the reactive extraction with Amberlite LA-2 occurs by means of the interfacial formation of an aminic adduct with three extractant molecules in low-polar solvent, or of an salt with one extractant molecule in higher polar solvent. Similarly, the extraction with D2EHPA is based on the formation of an acidic adduct with two extractant molecules in n-heptane, or of a salt with one extractant molecule in dichloromethane. The most efficient extraction has been reached for the combination Amberlite LA-2-dichloromethane.

  12. 2-Aminobenzoic acid–4,4′-bipyridine (2/1

    Directory of Open Access Journals (Sweden)

    Hadi D. Arman

    2013-09-01

    Full Text Available The asymmetric unit of title co-crystal, C10H8N2·2C7H7NO2, comprises a centrosymmetric 4,4′-bipyridine molecule, and a 2-aminobenzoic acid molecule in a general position. The latter is effectively planar [C—C—C—O torsion angle = 5.0 (3°] owing to an intramolecular N—H...O(carbonyl hydrogen bond. Three-molecule aggregates are formed via O—H...N(pyridyl hydrogen bonds and these are connected into supramolecular layers in the bc plane by N—H...O(carbonyl hydrogen bonds and π–π interactions between pyridyl and benzene rings [inter-centroid distance = 3.634 (2 Å]. Layers are connected along the a axis by weak π–π interactions between benzene rings [3.964 (2 Å].

  13. Magnetic whiskers of p-aminobenzoic acid and their use for preparation of filled and microchannel silicone rubbers

    International Nuclear Information System (INIS)

    Semenov, V. V.; Loginova, V. V.; Zolotareva, N. V.; Razov, E. N.; Kotomina, V. E.; Kruglov, A. V.

    2016-01-01

    A thin cobalt layer has been formed on the surface of p-aminobenzoic acid whiskers by chemical vapor deposition (CVD). The metallized crystals have been oriented in liquid polydimethylsiloxane rubber by applying a dc magnetic field. After vulcanization, the filler has been removed by processing in an alcohol solution of trifluoroacetic acid. The cobalt deposition on the surface of the organic compound and the properties of metallized whiskers are investigated by optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

  14. Aminobenzoate modified MgAl hydrotalcites as a novel smart additive of reinforced concrete for anticorrosion applications

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.R.; Cerezo, J.; Mol, J.M.C.; Polder, R.B.

    2013-01-01

    A carbonate form of MgAl hydrotalcite, Mg(2)Al-CO3 and its p-aminobenzoate (pAB) modified derivative, Mg(2)Al-pAB, were synthesized and characterized by means of XRD, FT-IR and TG/DSC. The anticorrosion behavior of Mg(2)Al-pAB was evaluated based on open circuit potential (OCP) of carbon steel in

  15. The Structure of p-Aminobenzoic Acid in Water: Studies Combining UV-Vis, NEXAFS and RIXS Spectroscopies

    International Nuclear Information System (INIS)

    Gainar, A; Stevens, J S; Schroeder, S L M; Suljoti, E; Xiao, J; Golnak, R; Aziz, E F

    2016-01-01

    NEXAFS-RIXS and home laboratory-based UV-Vis absorption spectroscopy are combined to examine the speciation and electronic structure of para -aminobenzoic acid (PABA) in aqueous solution as a function of pH. DFT and TD-DFT electronic structure calculations reproduce the experimental trends and provide a correlation between the experimental HOMO↔LUMO gap as well as the electronic transitions between molecular orbitals in the non-ionic, anionic and cationic forms of PABA. (paper)

  16. Magnetic whiskers of p-aminobenzoic acid and their use for preparation of filled and microchannel silicone rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, V. V., E-mail: vvsemenov@iomc.ras.ru; Loginova, V. V.; Zolotareva, N. V. [Russian Academy of Sciences, Razuvaev Institute of Organometallic Chemistry (Russian Federation); Razov, E. N. [Lobachevsky Nizhny Novgorod State University (Russian Federation); Kotomina, V. E.; Kruglov, A. V. [Lobachevsky Nizhny Novgorod State University, Physical‒Technical Research Institute (Russian Federation)

    2016-07-15

    A thin cobalt layer has been formed on the surface of p-aminobenzoic acid whiskers by chemical vapor deposition (CVD). The metallized crystals have been oriented in liquid polydimethylsiloxane rubber by applying a dc magnetic field. After vulcanization, the filler has been removed by processing in an alcohol solution of trifluoroacetic acid. The cobalt deposition on the surface of the organic compound and the properties of metallized whiskers are investigated by optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

  17. Therapeutic effect of para aminobenzoic acid (PABA) on the rat cornea administered in different ways after x-irradiation

    International Nuclear Information System (INIS)

    Panova, I.G.; Mel'nikova, I.I.; Stroeva, O.G.

    1997-01-01

    Comparative analysis of cytological state of nuclear apparatus in the mice cornea basal layer is carried out by two various method of introducing the para-aminobenzoic acid (PABA) after x-ray irradiation: 1) subcutaneous injections and 2) application of the solution on the cornea. The fact that PABA produced medicinal effect on the cornea of the irradiated mice by subcutaneous injections, shows that this action proceeds on the whole-body level

  18. Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal 2-aminobenzoates

    Science.gov (United States)

    Samsonowicz, M.; Świsłocka, R.; Regulska, E.; Lewandowski, W.

    2008-09-01

    The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons ( 1H NMR) and carbons ( 13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G ∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds.

  19. The vitamin-like dietary supplement para-aminobenzoic acid enhances the antitumor activity of ionizing radiation

    International Nuclear Information System (INIS)

    Xavier, Sandhya; MacDonald, Shannon; Roth, Jennifer; Caunt, Maresa; Akalu, Abebe; Morais, Danielle; Buckley, Michael T.; Liebes, Leonard; Formenti, Silvia C.; Brooks, Peter C.

    2006-01-01

    Purpose: To determine whether para-aminobenzoic acid (PABA) alters the sensitivity of tumor cells to ionizing radiation in vitro and in vivo. Methods and Materials: Cellular proliferation was assessed by WST-1 assays. The effects of PABA and radiation on tumor growth were examined with chick embryo and murine models. Real-time reverse transcriptase-polymerase chain reaction and Western blotting were used to quantify p21 CIP1 and CDC25A levels. Results: Para-aminobenzoic acid enhanced (by 50%) the growth inhibitory activity of radiation on B16F10 cells, whereas it had no effect on melanocytes. Para-aminobenzoic acid enhanced (50-80%) the antitumor activity of radiation on B16F10 and 4T1 tumors in vivo. The combination of PABA and radiation therapy increased tumor apoptosis. Treatment of tumor cells with PABA increased expression of CDC25A and decreased levels of p21 CIP1 . Conclusions: Our findings suggest that PABA might represent a compound capable of enhancing the antitumor activity of ionizing radiation by a mechanism involving altered expression of proteins known to regulate cell cycle arrest

  20. Ethyl-p-aminobenzoate (Benzocaine): efficacy as an anesthetic for five species of freshwater fish

    Science.gov (United States)

    Dawson, V.K.; Gilderhus, P.A.

    1979-01-01

    Ethyl-p-aminobenzoate (benzocaine) was tested for its efficacy as an anesthetic for rainbow trout (Salmo gairdnerii, brown trout (Salmo truttas, northern pike (Esox lucius). carp (Cyprinus carpio), and largemouth bass (Mieropterus salmoidesi. Since benzocaine is not water soluble, it was applied with acetone as a carrier. Concentrations of 100 to 200 mg!l were required for large adult northern pike, compared with 50 to 100 mg/l for small fish. Rates of sedation and recovery were slower in cold water than in warm water. Water hardness had little influence on the activity of benzocaine. Fish were anesthetized faster and recovered more slowly in acid than in alkaline water. Benzocaine produced deep anesthesia, but concentrations that rendered the fish handleable within 5 min were generally not safe for exposures longer than 15 min. Concentrations of benzocaine efficacious for fish were not acutely toxic to eggs of coho salmon (Oncorhynchus kisutch), chinook salmon (Oncorhynchus tshauiytschas, rainbow trout, brown trout, or lake trout (Salvelinus namaycush). Benzocaine is not registered for fishery use and is neither more effective nor safer than the registered anesthetic, tricaine methanesulfonate (MS-222l.

  1. Clinical study of p-aminobenzoic acid-N-xyloside Na in advanced cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, M.; Ota, K. (Aichi Cancer Center, Nagoya (Japan))

    1982-02-01

    Therapeutic effect of p-aminobenzoic acid-N-xyloside Na (K-247) were studied. Eleven patients with a variety of solid tumors were treated with K-247 alone. K-247 was given orally 800 mg daily for 4 weeks. As for side effect of the drug, only mild gastritis was observed in a few patients. Partial response (over 25% reduction of tumor size) with a median duration of two months was observed in 3 patients. These cases were metastatic tumor of lung from the carcinoma of thyroid, metastatic tumors of lung from the carcinoma of kidney, and mediastinal tumor. In eight patients the response was classified as no change and in one patient there was progressive disease. Thus K-247 has some therapeutic activity in patients with solid tumor. Combination therapy of irradiation and administration of K-247 were also studied. In the twelve patients receiving the combination therapy, partial response was observed in 7 patients with complete response in 3 patients. In some patients it seems that the effect of irradiation was enhanced by K-247 administration. To confirm this observation, randomized controlled trial is required.

  2. 2-Aminobenzoic acid–4-[2-(pyridin-4-ylethyl]pyridine (2/1

    Directory of Open Access Journals (Sweden)

    Hadi D. Arman

    2013-11-01

    Full Text Available The asymmetric unit of the title co-crystal, C12H12N2·2C7H7NO2, comprises a centrosymmetric 4-[2-(pyridin-4-ylethyl]pyridine molecule and a 2-aminobenzoic acid molecule in a general position. The acid has a small twist between the carboxylic acid residue and the ring [dihedral angle = 7.13 (6°] despite the presence of an intramolecular N—H...O(carbonyl hydrogen bond. Three-molecule aggregates are formed via O—H...N(pyridyl hydrogen bonds, and these are connected into supramolecular layers in the bc plane by N—H...O(carbonyl hydrogen bonds and π–π interactions between pyridine and benzene rings [inter-centroid distance = 3.6332 (9 Å]. Layers are connected along the a axis by weak π–π interactions between benzene rings [3.9577 (10 Å].

  3. Characterization of carbohydrates using highly fluorescent 2-aminobenzoic acid tag following gel electrophoresis of glycoproteins.

    Science.gov (United States)

    Anumula, K R; Du, P

    1999-11-15

    Application of the most sensitive fluorescent label 2-aminobenzoic acid (anthranilic acid, AA) for characterization of carbohydrates from the glycoproteins ( approximately 15 pmol) separated by polyacrylamide gel electrophoresis is described. AA label is used for the determination of both monosaccharide composition and oligosaccharide map. For the monosaccharide determination, bands containing the glycoprotein of interest are excised from the polyvinylidene fluoride (PVDF) membrane blots, hydrolyzed in 20% trifluoroacetic acid, derivatized, and analyzed by C-18 reversed-phase high-performance liquid chromatography. For the oligosaccharide mapping, bands were digested with peptide N-glycosidase F (PNGase F) in order to release the N-linked oligosaccharides, derivatized, and analyzed by normal-phase anion-exchange chromatography. For convenience, the PNGase F digestion was performed in 1:100 diluted ammonium hydroxide overnight. The oligosaccharide yield from ammonium hydroxide-PNGase F digestion was better or equal to all the other reported procedures, and the presumed "oligosaccharide-amine" product formed in the reaction mixture did not interfere with labeling of the oligosaccharides under the conditions used for derivatization. Sequencing of oligosaccharides can be performed using the same mapping method following treatment with an array of glycosidases. In addition, the mapping method is useful for determining the relative and simultaneous distribution of sialic acid and fucose. Copyright 1999 Academic Press.

  4. Clinical study of p-aminobenzoic acid-N-xyloside Na in advanced cancer patients

    International Nuclear Information System (INIS)

    Fukushima, Masanori; Ota, Kazuo

    1982-01-01

    Therapeutic effect of p-aminobenzoic acid-N-xyloside Na (K-247) were studied. Eleven patients with a variety of solid tumors were treated with K-247 alone. K-247 was given orally 800 mg daily for 4 weeks. As for side effect of the drug, only mild gastritis was observed in a few patients. Partial response (over 25% reduction of tumor size) with a median duration of two months was observed in 3 patients. These cases were metastatic tumor of lung from the carcinoma of thyroid, metastatic tumors of lung from the carcinoma of kidney, and mediastinal tumor. In eight patients the response was classified as no change and in one patient there was progressive disease. Thus K-247 has some therapeutic activity in patients with solid tumor. Combination therapy of irradiation and administration of K-247 were also studied. In twelve patients received the conbination therapy, partial response was observed in 7 patients with complete response in 3 patients. In some patients it seems that the effect of irradiation was enhanced by K-247 administration. To confirm this observation, randomized controlled trial is required. (author)

  5. 3-Aminobenzoic acid–4,4′-bipyridine (2/3

    Directory of Open Access Journals (Sweden)

    Pornsuda Lhengwan

    2012-08-01

    Full Text Available The asymmetric unit of the title compound, 3C10H8N2·2C7H7NO2, consists of three molecules of 4,4′-bipyridine (bpy and two molecules of 3-aminobenzoic acid (bza. Two molecules of bza and two molecules of bpy are connected via O—H...N, N—H...N and N—H...O hydrogen bonds, forming forming infinite double-stranded zigzag chains along the c axis. The third molecule of bpy is linked to the chain by weak C—H...O interactions. Adjacent chains are linked via π–π interactions [centroid–centroid distances = 3.759 (3–3.928 (3 Å] involving the pyridine rings of bpy molecules, resulting in a sheet-like structure parallel to (100. These sheets are stacked via C—H...π interactions, resulting finally in the formation of a three-dimensional supramolecular structure.

  6. Synthesis, structure, growth and characterization of a novel organic NLO single crystal: Morpholin-4-ium p-aminobenzoate

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, G. [Department of Physics, Anna University of Technology Tiruchirappalli, Tiruchirappalli 620024 (India); Ravi Kumar, K.; Sridhar, B. [X-ray Crystallography Division, Indian Institute of Chemical Technology, CSIR, Hyderabad 500007 (India); Brahadeeswaran, S., E-mail: sbrag67@yahoo.com [Department of Physics, Anna University of Technology Tiruchirappalli, Tiruchirappalli 620024 (India)

    2012-09-15

    Highlights: ► A new organic NLO crystal morpholin-4-ium p-aminobenzoate has been grown for the first time. ► The structure is reported for the first time in the literature. ► Thermal, optical and SHG studies suggest its suitability for various NLO applications. -- Abstract: The title compound, morpholin-4-ium p-aminobenzoate (MPABA)(C{sub 4}H{sub 10}NO{sup +},C{sub 7}H{sub 6}NO{sub 2}{sup −}), has been synthesized for the first time by the addition of morpholine with 4-aminobenzoic acid in equi-molar ratio and good quality single crystals have been grown by solution growth technique using methanol as a solvent. The molecular structure of the compound was solved and refined by Direct Methods using SHELXS97 and full-matrix least-squares technique using SHELXL97, respectively. MPABA crystallizes in a monoclinic system with unit cell parameters, a = 5.948(5) Å, b = 18.033(4) Å, c = 10.577(5) Å, β = 90.40(1)° and non-centrosymmetric space group Cc. The experimentally measured density and chemical compositions were found to be in good agreement with the theoretical values. The phases and functional groups of MPABA have been identified and confirmed through powder X-ray diffraction and Fourier transform infrared (FTIR) studies, respectively. The thermal stability and decomposition details were studied through TG/DTA thermograms. The UV–visible transmission spectra were recorded for the grown crystal and its NLO characteristic was explored by powder second harmonic generation (SHG) studies.

  7. Thermodynamic study on salt effects on complex formation of α-, β- and γ-cyclodextrins with p-aminobenzoic acid

    International Nuclear Information System (INIS)

    Chibunova, E.S.; Kumeev, R.S.; Terekhova, I.V.

    2015-01-01

    Highlights: • Thermodynamic study on salt effects in CD/pABA complex formation was performed. • Effects of KCl, KH 2 PO 4 and K 2 SO 4 are insignificant and nonspecific. • Specific influence of KBr is caused by the ability of Br − to penetrate into CD cavity. • Coexistence of two complexation equilibria is accompanied by solvent reorganization. - Abstract: The aim of this work was to gain a deeper understanding of salt effects in the inclusion complex formation of cyclodextrins. For this purpose, thermodynamic study of complex formation of α-, β- and γ-cyclodextrins with p-aminobenzoic acid was carried out in water and solutions of KCl, KBr, KH 2 PO 4 and K 2 SO 4 (0.2 mol/kg). Stability constants were calculated from the binding isotherms obtained on the basis of 1 H NMR measurements. Enthalpy and entropy of complex formation were estimated from the van’t Hoff plots. It was found that effects of KCl, KH 2 PO 4 and K 2 SO 4 are insignificant, while the influence of KBr on complex formation of cyclodextrins with p-aminobenzoic acid is more pronounced and results in a decrease of the stability constants. Specific action of Br − is caused by the ability of these anions to penetrate into macrocyclic cavity. Coexistence of two complexation equilibria in KBr solution is accompanied by significant solvent reorganization originated from more intensive dehydration of the interacting species. This results in an increase of the enthalpy and entropy of complex formation. Manifestation of Br − effect was found to be the same in the binding of p-aminobenzoic acid with α-, β- and γ-cyclodextrins.

  8. Synthesis, structure, growth and characterization of a novel organic NLO single crystal: Morpholin-4-ium p-aminobenzoate

    International Nuclear Information System (INIS)

    Shanmugam, G.; Ravi Kumar, K.; Sridhar, B.; Brahadeeswaran, S.

    2012-01-01

    Highlights: ► A new organic NLO crystal morpholin-4-ium p-aminobenzoate has been grown for the first time. ► The structure is reported for the first time in the literature. ► Thermal, optical and SHG studies suggest its suitability for various NLO applications. -- Abstract: The title compound, morpholin-4-ium p-aminobenzoate (MPABA)(C 4 H 10 NO + ,C 7 H 6 NO 2 − ), has been synthesized for the first time by the addition of morpholine with 4-aminobenzoic acid in equi-molar ratio and good quality single crystals have been grown by solution growth technique using methanol as a solvent. The molecular structure of the compound was solved and refined by Direct Methods using SHELXS97 and full-matrix least-squares technique using SHELXL97, respectively. MPABA crystallizes in a monoclinic system with unit cell parameters, a = 5.948(5) Å, b = 18.033(4) Å, c = 10.577(5) Å, β = 90.40(1)° and non-centrosymmetric space group Cc. The experimentally measured density and chemical compositions were found to be in good agreement with the theoretical values. The phases and functional groups of MPABA have been identified and confirmed through powder X-ray diffraction and Fourier transform infrared (FTIR) studies, respectively. The thermal stability and decomposition details were studied through TG/DTA thermograms. The UV–visible transmission spectra were recorded for the grown crystal and its NLO characteristic was explored by powder second harmonic generation (SHG) studies.

  9. Anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) via benzoyl-coenzyme A (CoA) and cyclohex-1-enecarboxyl-CoA in a denitrifying bacterium.

    Science.gov (United States)

    Lochmeyer, C; Koch, J; Fuchs, G

    1992-06-01

    The enzymes catalyzing the initial reactions in the anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) were studied with a denitrifying Pseudomonas sp. anaerobically grown with 2-aminobenzoate and nitrate as the sole carbon and energy sources. Cells grown on 2-aminobenzoate are simultaneously adapted to growth with benzoate, whereas cells grown on benzoate degrade 2-aminobenzoate several times less efficiently than benzoate. Evidence for a new reductive pathway of aromatic metabolism and for four enzymes catalyzing the initial steps is presented. The organism contains 2-aminobenzoate-coenzyme A ligase (2-aminobenzoate-CoA ligase), which forms 2-aminobenzoyl-CoA. 2-Aminobenzoyl-CoA is then reductively deaminated to benzoyl-CoA by an oxygen-sensitive enzyme, 2-aminobenzoyl-CoA reductase (deaminating), which requires a low potential reductant [Ti(III)]. The specific activity is 15 nmol of 2-aminobenzoyl-CoA reduced min-1 mg-1 of protein at an optimal pH of 7. The two enzymes are induced by the substrate under anaerobic conditions only. Benzoyl-CoA is further converted in vitro by reduction with Ti(III) to six products; the same products are formed when benzoyl-CoA or 2-aminobenzoyl-CoA is incubated under reducing conditions. Two of them were identified preliminarily. One product is cyclohex-1-enecarboxyl-CoA, the other is trans-2-hydroxycyclohexane-carboxyl-CoA. The complex transformation of benzoyl-CoA is ascribed to at least two enzymes, benzoyl-CoA reductase (aromatic ring reducing) and cyclohex-1-enecarboxyl-CoA hydratase. The reduction of benzoyl-CoA to alicyclic compounds is catalyzed by extracts from cells grown anaerobically on either 2-aminobenzoate or benzoate at almost the same rate (10 to 15 nmol min-1 mg-1 of protein). In contrast, extracts from cells grown anaerobically on acetate or grown aerobically on benzoate or 2-aminobenzoate are inactive. This suggests a sequential induction of the enzymes.

  10. Nanocomposite Thin Film of Poly(3-aminobenzoic acid and Multiwalled Carbon Nanotubes Fabricated through an Electrochemical Method

    Directory of Open Access Journals (Sweden)

    Paphawadee Netsuwan

    2014-01-01

    Full Text Available The composite thin films of poly(3-aminobenzoic acid (PABA and multiwalled carbon nanotubes (MWNTs are successfully fabricated through an electrochemical method. The composite mixtures containing 50 mM of 3-aminobenzoic acid with various concentrations of MWNTs (1.0, 2.5, 5.0, 7.5, and 10 mg/mL in 0.5 M H2SO4 were prepared and used in this study. Cyclic voltammetry (CV was used for fabrication and monitoring the electropolymerization of the composite thin films with potential range of 0 to 1100 mV for 5 cycles at scan rate of 20 mV/s on indium tin oxide- (ITO-coated glass substrate. UV-vis absorption spectroscopy, atomic force microscopy (AFM, and scanning electron microscopy (SEM techniques were employed to characterize the obtained composite thin films. It was found that MWNTs can enhance the peak current of CV traces of the PABA/MWNTs composite thin films without affecting the UV-vis absorption spectra. The surface morphology of the thin films can be studied using AFM and SEM techniques.

  11. Preparation of three terbium complexes with p-aminobenzoic acid and investigation of crystal structure influence on luminescence property

    International Nuclear Information System (INIS)

    Ye Chaohong; Sun Haoling; Wang Xinyi; Li Junran; Nie Daobo; Fu Wenfu; Gao Song

    2004-01-01

    Three new rare earth p-aminobenzoic acid complexes, [Tb 2 L 6 (H 2 O) 2 ] n (1), [Tb 2 L 6 (H 2 O) 4 ].2H 2 O (2) and [Tb(phen) 2 L 2 (H 2 O) 2 ](phen)L·4H 2 O (3) (HL: p-aminobenzoic acid; phen: 1, 10-phenanthroline), with different structural forms are reported in this paper. Complex 1 is a polymolecule with a two-dimensional plane structure. Compound 2 is a binuclear molecule, and 3 appears to be a mononuclear complex. The fluorescence intensity, the fluorescence life-time and emission quantum yield of 2, which has two coordination water molecules, is better than those of 1, which has only one coordination water molecule. This is an unusual phenomenon for general fluorescent rare earth complexes. The fluorescence performance of 3 is the most unsatisfactory among the three complexes. Their crystal structures show that the coordination mode of the ligand is an important factor influencing the luminescence properties of a fluorescent rare earth complex

  12. Influence of organic component on geometry and stability of the Dy(3) complexes with benzoic and aminobenzoic acids in water-80 vol.% DMSO(DMFA) mixtures

    International Nuclear Information System (INIS)

    Kondrashina, Yu.G.; Mustafina, A.R.; Devyatov, F.V.; Vul'fson, S.G.; Kazanskij Gosudarstvennyj Univ., Kazan

    1995-01-01

    Data of pH-metric and magnetooptical analyses were used to evaluate stability and structure of benzoate and aminobenzoate dysprosium (3) complexes in water and water - 80 vol.% DMSO (DMFA) mixtures. Factors, dictating change of complex structure and stability when passing from water to organic water solvents, are discussed. 19 refs.; 2 figs.; 1 tab

  13. IN VITRO STUDY OF ANTI-INFLUENZA ACTIVITY OF PARA-AMINOBENZOIC ACID AND PROSPECTS OF NASAL DRUG DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Nefedova L.

    2017-06-01

    Full Text Available is a vitamin-like substance, para-aminobenzoic acid (PABA. The aim of this work is to study antiviral activity of para-aminobenzoic acid, ε-aminocaproic acid, and their mixture against influenza virus, to evaluate their cytotoxic effect and to calculate their selectivity index by in vitro methods. Materials and Methods. For evaluation of cytotoxic concentration (CC50 of the substance tested, we used MDCK cell culture. For determination of anti-influenza activity of PABA, ε-АCA, and their mixture under conditions of in vitro experiment, we used 24-hour passaged MDCK culture cells of dog’s kidney, influenza virus strain А/FM/1/47 (H1N1, infected titer of which in MDCK culture cells of was between 3.0 and 9.0 lgID50. Results. As a result of our studies, we have determined that PABA in the concentration range studied from 10 to 1,000 ug/ml did not have any cytopahtic effect in MDCK culture cells. We calculated selectivity index (SI for PABA, that was equal SI=128205, this fact confirm high level of therapeutic safety of this substance. The result of our experiments demonstrate that anti-influenza activity of PABA solution is almost 100 times higher than that of “ACA”, furthermore in our in vitro experiment the mixture of PABA and ε-aminocaproic acid (in ratio 1:100 demonstrates a synergetic effect. In addition, for combination of PABA and εАКК (1:100 we calculated fractional inhibitory coefficient FIC=0.79, that indicates to moderate synergetic effect of these substances. Conclusions. As a result of our in vitro studies, we have determined a high-level antiviral activity of para-aminobenzoic acid against influenza virus, and in combination with ε-aminocaproic acid it demonstrated a synergetic effect. We have determined that PABA does not exhibit any cytotoxic effect on MDCK culture cells in the concentration range studied and demonstrates high level of therapeutic safety.

  14. Mechanochemical synthesis of bumetanide-4-aminobenzoic acid molecular cocrystals: a facile and green approach to drug optimization.

    Science.gov (United States)

    Bruni, Giovanna; Maietta, Mariarosa; Berbenni, Vittorio; Mustarelli, Piercarlo; Ferrara, Chiara; Freccero, Mauro; Grande, Vincenzo; Maggi, Lauretta; Milanese, Chiara; Girella, Alessandro; Marini, Amedeo

    2014-08-07

    Molecular cocrystals are of growing interest in pharmaceutics for their improved physicochemical properties. Their mechanochemical synthesis is very promising, being easy, cheap, and "green". Here, for the first time, we report on cocrystallization of bumetanide, a diuretic and natriuretic active principle, and 4-aminobenzoic acid. The synthesis is performed both by wet and dry grinding. The cocrystal formation was investigated with a wide range of techniques, including solid-state NMR, IR, XRD, microscopy, and thermal analysis. Wet and dry grinding procedures led to different cocrystal polymorphs. In particular, the dry method gave a cocrystal by powder amorphization and subsequent crystallization. DFT calculations at the B3LYP/6-31+G(d,p) level of theory shed light on the H-bond scheme at the basis of cocrystal formation. The cocrystals showed improved solubility and dissolution rate with respect to the drug alone. This could guarantee a faster absorption and a better bioavailability of the active principle.

  15. Crystal structure of trans-bis(diethanolamine-κ3O,N,O′manganese(II bis(3-aminobenzoate

    Directory of Open Access Journals (Sweden)

    Aziz B. Ibragimov

    2016-04-01

    Full Text Available Reaction of m-aminobenzoic acid (MABA, diethanolamine (DEA and MnCl2·4H2O led to the formation of the title salt, [Mn(C4H11NO22](C7H6NO22. In the complex cation, the Mn2+ ion is located on an inversion centre and is coordinated by two symmetry-related tridentate DEA molecules, leading to the formation of a slightly distorted MnN2O4 octahedron. The MABA− counter-anions are connected to the complex ion by a pair of rather strong O—H...O hydrogen bonds, yielding a 1:2 supramolecular aggregate. Much weaker N—H...O hydrogen bonds connect neighbouring aggregates into a three-dimensional network structure.

  16. Separation of saccharides derivatized with 2-aminobenzoic acid by capillary electrophoresis and their structural consideration by nuclear magnetic resonance.

    Science.gov (United States)

    He, Liping; Sato, Kae; Abo, Mitsuru; Okubo, Akira; Yamazaki, Sunao

    2003-03-01

    Saccharides including mono- and disaccharides were quantitatively derivatized with 2-aminobenzoic acid (2-AA). These derivatives were then separated by capillary zone electrophoresis with UV detection using 50mM sodium phosphate buffer as the running electrolyte solution. In particular, the saccharide derivatives with the same molecular weight as 2-AA aldohexoses (mannose and glucose) and 2-AA aldopentoses (ribose and xylose) were well separated. The underlying reasons for separation were explored by studying their structural data using 1H and 13C NMR. It was found that the configurational difference between their hydroxyl group at C2 or C3 could cause the difference in Stokes' radii between their molecules and thus lead to different electrophoretic mobilities. The correlation between the electrophoretic behavior of these carbohydrate derivatives and their structures was studied utilizing the calculated molecular models of the 2-AA-labeled mannose, glucose, ribose, and xylose.

  17. The role of p-aminobenzoic acid in the repair of injuries induced by UV- and γ-radiation

    International Nuclear Information System (INIS)

    Rapoport, I.A.; Vasil'eva, S.V.; Davnichenko, L.S.

    1979-01-01

    For the first time it was proved that low doses of p-aminobenzoic acid (PABA) were capable of sharply decreasing lethal mutational effects of UV light and less significantly-gamma effect on a bacterial cell. The experiments were carried out on E.Coli strains which differed in the activity of ferment system of DNA UV-induced injuries reparation. VV radiation dose equaled 10-1500 erd/mm 2 . PABA capability to intensify the reparative process under mutagenic effects of 3 main types: chemical, UV as a representative of non-penetrating radiation, and penetrating radiation permitted to characterize this compound as ''reparagen''. It was emphasized that the application of reparagens capable of intensifying or weakening the reparative process permitted to observe different effects of reparation dependence on the concentration of a chemical agent being introduced from outside and localize the process of reparagen effect in time

  18. Halogeno-substituted 2-aminobenzoic acid derivatives for negative ion fragmentation studies of N-linked carbohydrates.

    Science.gov (United States)

    Harvey, David J

    2005-01-01

    Negative ion electrospray mass spectra of high-mannose N-linked glycans derivatised with 2-aminobenzoic acids and ionised from solutions containing ammonium hydroxide gave prominent [M-H](-) ions accompanied by weaker [M-2H](2-) ions. Fragmentation of both types of ions gave prominent singly charged glycosidic cleavage ions containing the derivatised reducing terminus and ions from the non-reducing terminus that appeared to be products of cross-ring cleavages. Differentiation of these two groups of ions was conveniently achieved in a single spectrum by use of chloro- or bromo-substituted benzoic acids in order to label ions containing the derivative with an atom with a distinctive isotope pattern. Fragmentation of the doubly charged ions gave more abundant fragments, both singly and doubly charged, than did fragmentation of the singly charged ions, but information of chain branching was masked by the appearance of prominent ions produced by internal cleavages. Copyright (c) 2005 John Wiley & Sons, Ltd.

  19. UV-irradiation potentiates the antimutagenicity of p-aminobenzoic and p-aminosalicylic acids in Salmonella typhimurium

    International Nuclear Information System (INIS)

    Gichner, T.; Baburek, I.; Veleminsky, J.; Kappas, A.

    1991-01-01

    UV-irradiation (254 nm, 10 or 20 J/cm 2 ) of p-aminobenzoic acid (PABA) and p-aminosalicylic acid (NaPAS) potentiated their antimuta-genicity towards N-methyl-N'-nitro-N-nitrosoguanide metagenesis in Salmonella typhimurium. Their inhibitory action towards the formation of mutagen N-methyl-N-mitrosourea from the nitrosation mixture of N-methylurea and nitrite was also increased by UV-irradiation. In contrast, UV-irradiated PABA exhibited no inhibitory effects towards the mutagenicity of sodium azide or 3-azidoglycerol. Neither PABA nor NaPAS not their UV-irradiation products were themselves mutagenic in the Ames assay. 13 refs.; 5 tabs

  20. Mass spectrometric-based stable isotopic 2-aminobenzoic acid glycan mapping for rapid glycan screening of biotherapeutics.

    Science.gov (United States)

    Prien, Justin M; Prater, Bradley D; Qin, Qiang; Cockrill, Steven L

    2010-02-15

    Fast, sensitive, robust methods for "high-level" glycan screening are necessary during various stages of a biotherapeutic product's lifecycle, including clone selection, process changes, and quality control for lot release testing. Traditional glycan screening involves chromatographic or electrophoretic separation-based methods, and, although reproducible, these methods can be time-consuming. Even ultrahigh-performance chromatographic and microfluidic integrated LC/MS systems, which work on the tens of minute time scale, become lengthy when hundreds of samples are to be analyzed. Comparatively, a direct infusion mass spectrometry (MS)-based glycan screening method acquires data on a millisecond time scale, exhibits exquisite sensitivity and reproducibility, and is amenable to automated peak annotation. In addition, characterization of glycan species via sequential mass spectrometry can be performed simultaneously. Here, we demonstrate a quantitative high-throughput MS-based mapping approach using stable isotope 2-aminobenzoic acid (2-AA) for rapid "high-level" glycan screening.

  1. Effects of the rate of supersaturation generation on polymorphic crystallization of m-hydroxybenzoic acid and o-aminobenzoic acid

    Science.gov (United States)

    He, Guangwen; Wong, Annie B. H.; Chow, Pui Shan; Tan, Reginald B. H.

    2011-01-01

    Effects of the rate of supersaturation generation on polymorphic crystallization have been investigated through evaporation and cooling crystallization experiments of m-hydroxybenzoic acid (m-HBA) in methanol, acetone and ethyl acetate, and o-aminobenzoic acid (o-ABA) in ethanol. The rate of supersaturation generation has been altered by systematically changing either the cooling rate or the evaporation rate of solvent using a jacketed crystallizer and a microfluidic evaporation device, respectively. The results have revealed that the rate of supersaturation generation and the tendency of the formation of the less stable polymorph are positively correlated. Kinetic effects are dominant when the rate of supersaturation generation is high, thereby producing the metastable polymorphs (orthorhombic m-HBA; Form II of o-ABA); on the contrary, more stable polymorphs (monoclinic m-HBA; Forms III and I of o-ABA) are formed when the rate of supersaturation generation is low and the thermodynamic effects are prevailing.

  2. Role of p-aminobenzoic acid in the repair of injuries induced by UV- and. gamma. -radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rapoport, I A; Vasil' eva, S V; Davnichenko, L S [AN SSSR, Moscow. Inst. Khimicheskoj Fiziki

    1979-07-01

    For the first time it was proved that low doses of p-aminobenzoic acid (PABA) were capable of sharply decreasing lethal mutational effects of UV light and less significantly-gamma effect on a bacterial cell. The experiments were carried out on E.Coli strains which differed in the activity of ferment system of DNA UV-induced injuries reparation. UV radiation dose equaled 10-1500 erd/mm/sup 2/. PABA capability to intensify the reparative process under mutagenic effects of 3 main types: chemical, UV as a representative of non-penetrating radiation, and penetrating radiation permitted to characterize this compound as ''reparagen''. It was emphasized that the application of reparagens capable of intensifying or weakening the reparative process permitted to observe different effects of reparation dependence on the concentration of a chemical agent being introduced from outside and localize the process of reparagen effect in time.

  3. Raman and Terahertz Spectroscopic Investigation of Cocrystal Formation Involving Antibiotic Nitrofurantoin Drug and Coformer 4-aminobenzoic Acid

    Directory of Open Access Journals (Sweden)

    Yong Du

    2016-12-01

    Full Text Available Cocrystallization could improve most physicochemical properties of specific active pharmaceutical ingredients, which has great potential in pharmaceutical development. In this study, the cocrystal of nitrofurantoin and 4-aminobenzoic acid was prepared with solid-state (solvent-free or green-chemistry grinding approach, and the above cocrystal has been characterized by Raman and terahertz vibrational spectroscopic techniques. Spectral results show that the vibrational modes of the cocrystal within the whole spectral region are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman spectra. These results offer us unique means for characterizing the cocrystal conformation from the molecule-level, and provides us with rich information about the reaction dynamic of cocrystal formation within pharmaceutical fields.

  4. A dinuclear copper complex: bis(μ-4-aminobenzoatobis[aqua(1,10-phenanthrolinecopper(II] dichloride bis(4-aminobenzoic acid dihydrate

    Directory of Open Access Journals (Sweden)

    Miao-Ling Huang

    2008-08-01

    Full Text Available The title complex, [Cu2(C7H6NO22(C12H8N22(H2O2]·2C7H7NO2·2H2O, consists of a dinuclear [Cu2(C7H6NO22(C12H8N22(H2O2]2+ cation, two Cl− anions, two 4-aminobenzoic acid molecules and two disordered water molecules (site occupancy factors 0.5. The Cu(II ion adopts a distorted square-pyramidal geometry formed by two N atoms from the 1,10-phenanthroline ligand and two O atoms of the two 4-aminobenzoic acid ligands and one water O atom. The Cu...Cu separation is 3.109 (2 Å. A twofold axis passes through the mid-point of the Cu...Cu vector.

  5. Synthesis, characterization and evaluation of 1,3,5-triazine aminobenzoic acid derivatives for their antimicrobial activity.

    Science.gov (United States)

    Al-Zaydi, Khadijah M; Khalil, Hosam H; El-Faham, Ayman; Khattab, Sherine N

    2017-05-10

    Replacement of chloride ions in cyanuric chloride give several variants of 1,3,5-triazine derivatives which were investigated as biologically active small molecules. These compounds exhibit antimalarial, antimicrobial, anti-cancer and anti-viral activities, among other beneficial properties. On the other hand, treatment of bacterial infections remains a challenging therapeutic problem because of the emerging infectious diseases and the increasing number of multidrug-resistant microbial pathogens. As multidrug-resistant bacterial strains proliferate, the necessity for effective therapy has stimulated research into the design and synthesis of novel antimicrobial molecules. 1,3,5-Triazine 4-aminobenzoic acid derivatives were prepared by conventional method or by using microwave irradiation. Using microwave irradiation gave the desired products in less time, good yield and higher purity. Esterification of the 4-aminobenzoic acid moiety afforded methyl ester analogues. The s-triazine derivatives and their methyl ester analogues were fully characterized by FT-IR, NMR ( 1 H-NMR and 13 C-NMR), mass spectra and elemental analysis. All the synthesized compounds were evaluated for their antimicrobial activity. Some tested compounds showed promising activity against Staphylococcus aureus and Escherichia coli. Three series of mono-, di- and trisubstituted s-triazine derivatives and their methyl ester analogues were synthesized and fully characterized. All the synthesized compounds were evaluated for their antimicrobial activity. Compounds (10), (16), (25) and (30) have antimicrobial activity against S. aureus comparable to that of ampicillin, while the activity of compound (13) is about 50% of that of ampicillin. Compounds (13) and (14) have antimicrobial activity against E. coli comparable to that of ampicillin, while the activity of compounds (9-12) and (15) is about 50% of that of ampicillin. Furthermore, minimum inhibitory concentrations values for clinical isolates of

  6. Calcium phenylphosphonate as a host for 4-aminobenzoic acid-Synthesis, characterization, and cation adsorption from ethanol solution

    International Nuclear Information System (INIS)

    Lazarin, Angelica M.; Ganzerli, Thiago A.; Sernaglia, Rosana L.; Andreotti, Elza I.S.; Airoldi, Claudio

    2009-01-01

    Crystalline lamellar calcium phenylphosphonate retained 4-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1160-695 cm -1 interval confirmed the presence of the phosphonate groups attached to the inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 1532 and 1751 pm for the original and the intercalated compounds, respectively. The thermogravimetric curves of both layered compounds showed the release of water molecules and the organic moiety in distinct stages, to yield a final Ca(PO 3 ) 2 residue. Solid-state 31 P nuclear magnetic resonance spectra presented only one peak for the phenylphosphonate groups attached to the main inorganic polymeric structure near 12.4 ppm. The adsorption isotherms from ethanol gave the maximum adsorption capacities of 1.68 and 0.50 mmol g -1 for copper and cobalt, respectively, whose average stability constants followed Co > Cu; the number of ligands was determined as four for both cations.

  7. Simple and Robust N-Glycan Analysis Based on Improved 2-Aminobenzoic Acid Labeling for Recombinant Therapeutic Glycoproteins.

    Science.gov (United States)

    Jeong, Yeong Ran; Kim, Sun Young; Park, Young Sam; Lee, Gyun Min

    2018-03-21

    N-glycans of therapeutic glycoproteins are critical quality attributes that should be monitored throughout all stages of biopharmaceutical development. To reduce both the time for sample preparation and the variations in analytical results, we have developed an N-glycan analysis method that includes improved 2-aminobenzoic acid (2-AA) labeling to easily remove deglycosylated proteins. Using this analytical method, 15 major 2-AA-labeled N-glycans of Enbrel ® were separated into single peaks in hydrophilic interaction chromatography mode and therefore could be quantitated. 2-AA-labeled N-glycans were also highly compatible with in-line quadrupole time-of-flight mass spectrometry (MS) for structural identification. The structures of 15 major and 18 minor N-glycans were identified from their mass values determined by quadrupole time-of-flight MS. Furthermore, the structures of 14 major N-glycans were confirmed by interpreting the MS/MS data of each N-glycan. This analytical method was also successfully applied to neutral N-glycans of Humira ® and highly sialylated N-glycans of NESP ® . Furthermore, the analysis data of Enbrel ® that were accumulated for 2.5 years demonstrated the high-level consistency of this analytical method. Taken together, the results show that a wide repertoire of N-glycans of therapeutic glycoproteins can be analyzed with high efficiency and consistency using the improved 2-AA labeling-based N-glycan analysis method. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  8. Inhibitory effects of cytostatically active 6-aminobenzo[c]phenanthridines on cytochrome P450 enzymes in human hepatic microsomes.

    Science.gov (United States)

    Zebothsen, Inga; Kunze, Thomas; Clement, Bernd

    2006-07-01

    Besides assays for the evaluation of efficacy new drug candidates have to undergo extensive testings for enhancement of pharmaceutical drug safety and optimization of application. The objective of the present work was to investigate the pharmacokinetic drug drug interaction potential for the cytostatically active 6-aminobenzo[c]phenanthridines BP-11 (6-amino-11,12-dihydro-11-(4-hydroxy-3,5-dimethoxyphenyl)benzo[c]phenanthridine) and BP-D7 (6-amino-11-(3,4,5-trimethoxyphenyl)benzo[c]phenanthridine) in vitro through incubation with human hepatic microsomes and marker substrates. For these studies the cytochrome P-450 isoenzymes and corresponding marker substrates recommended by the EMEA (The European Agency for the Evaluation of Medicinal Products) were chosen. In detail these selective substrates were caffeine (CYP1A2), coumarin (CYP2A6), tolbutamide (CYP2C9), S-(+)-mephenytoin (CYP2C19), dextromethorphane (CYP2D6), chlorzoxazone (CYP2E1) and testosterone (CYP3A4). Incubations with each substrate were carried out without a possible inhibitor and in the presence of a benzo[c]phenanthridine or a selective inhibitor at varying concentrations. Marker activities were determined by HPLC (high performance liquid chromatography). For the isoenzymes showing more than 50% inhibition by the addition of 20 microM BP-11 or BP-D7 additional concentrations of substrate and inhibitor were tested for a characterization of the inhibition. The studies showed a moderate risk for BP-11 for interactions with the cytochrome P-450 isoenzymes CYP1A2, CYP2C9, CYP2D6 and CYP3A4. BP-D7, the compound with the highest cytotstatic efficacy, showed only a moderate risk for interactions with drugs, also metabolized by CYP3A4.

  9. Synthetic, spectroscopic and structural studies on 4-aminobenzoate complexes of divalent alkaline earth metals: x-ray crystal structures of [[Mg(H2O)6] (4-aba)2].2H2O and [Ca(H2O)2(4-aba)2] (4-aba=4-aminobenzoate)

    International Nuclear Information System (INIS)

    Murugavel, Ramaswamy; Karambelkar, Vivek V.; Anantharaman, Ganapathi

    2000-01-01

    Reactions between MCl 2 .nH 2 O (M = Mg, Ca, Sr, and Ba) and 4-aminobenzoic acid (4-abaH) result in the formation of complexes [(Mg(H 2 O) 6 )(4-aba) 2 ) .2H 2 O (I), [Ca(4-aba) 2 (H2 O ) 2 ] (2), [Sr(4-aba) 2 (H2 O ) 2 ] (3), and [Ba(4-aba) 2 Cl] (4), respectively. The new compounds 1 and 2, as well as the previously reported 3 and 4 form an extended intra- and intermolecular hydrogen bonded network in the solid-state. The compounds have been characterized by elemental analysis, pH measurements, thermogravimetric studies, and IR, NMR, and UV-Vis spectroscopy. The solid state structures of the molecules 1 and 2 have been determined by single crystal x-ray diffraction studies. In the case of magnesium complex 1, the dipositively charged Mg cation is surrounded by six water molecules and the two 4-aminobenzoate ligands show no direct bonding to the metal ion. The calcium ion in 2 is octa-coordinated with direct coordination of the 4-aminobenzoate ligands to the metal ion. The Ca-Ca separation in the polymeric chain of 2 is 3.9047(5) A. (author)

  10. The dynamics of molecular dimers in the crystals of m-aminobenzoic acid studied by inelastic neutron scattering (INS), Raman, IR spectroscopy and DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Pawlukojc, A.; Leciejewicz, J

    2004-03-29

    Inelastic neutron scattering, Raman and IR spectra were measured for m-aminobenzoic acid (MABA). Optimized geometries and observed frequencies were assigned using DFT calculation on the B3LYP/6-311G** level using Gaussian 98 and Gamess programs. Experimental structural and spectroscopic data are in good agreement with computations assuming the presence in the crystals of molecular dimers composed of two MABA molecules linked by a pair of O-H...O hydrogen bonds each provided by the carboxylic group. INS frequencies have been identified for the O-H (out of plane) mod0008.

  11. Substituent and structural effects on the kinetics of the reaction of N-(substituted phenylmethylene-m- and -p-aminobenzoic acids with diazodiphenylmethane

    Directory of Open Access Journals (Sweden)

    BRATISLAV Z. JOVANOVIC

    2007-12-01

    Full Text Available The rate constants for the reaction of twenty-two N-(substituted phenyl methylene-m- and -p-aminobenzoic acids with diazodiphenylmethane were determined in absolute ethanol at 30 °C. The effects of substituents on the reactivity of the investigated compounds were interpreted by correlation of the rate constants with LFER equations. The results of quantum mechanical calculations of the mole cular structure together with experimental results gave a better insight into the effects of structure on the transmission of electronic effects of the substituents. New σ constants for substituted benzylideneamino group were calculated.

  12. The simultaneous detection and quantification of p-aminobenzoic acid and its phase 2 biotransformation metabolites in human urine using LC-MS/MS.

    Science.gov (United States)

    Nortje, Carla; Jansen van Rensburg, Peet; Cooke, Cecile; Erasmus, Elardus

    2015-01-01

    p-Aminobenzoic acid (PABA) can be used as a probe substance to investigate glycine conjugation, a reaction of phase 2 biotransformation. An LC-MS/MS method for simultaneous quantification of PABA and its metabolites from human urine was developed and validated. The metabolites can be quantified with acceptable precision and accuracy directly from human urine samples after ingestion of 550 mg PABA. The developed LC-MS/MS assay is to our knowledge the first method available for the simultaneous quantification of PABA and its glycine conjugation metabolites in human urine and provides important quantitative data for studies of this phase 2 biotransformation pathway.

  13. Selective visual detection of Pb(II) ion via gold nanoparticles coated with a dithiocarbamate-modified 4′-aminobenzo-18-crown-6

    International Nuclear Information System (INIS)

    Mehta, Vaibhavkumar N.; Kailasa, Suresh Kumar; Solanki, Jignasa N.

    2014-01-01

    We have developed a crown ether based selective colorimetric sensing scheme for the determination of Pb(II) ion by using gold nanoparticles modified with dithiocarbamate derivative of 4′-aminobenzo-18-crown-6 that acts as a colorimetric probe. Monodisperse Au-NPs were prepared by reacting 4′-aminobenzo-18-crown-6 with carbon disulfide to generate the dithiocarbamate ligand which was then added to the Au-NPs to form a supramolecular assembly on their surface. The Au-NPs modified in this way undergo aggregation in the presence of Pb(II) ions, and this causes the color to change from red to blue. The Pb(II)-induced aggregation can be monitored by using UV-visible spectrometry and even with the bare eye. The absorbance ratio (A 650nm /A 520nm ) is linearly related to the concentration of Pb(II) in the 0.1 to 75 μM range (with a correlation coefficient of 0.9957), and the detection limit is 50 nM which is lower than the allowable level (75 nM) as defined by the US EPA. The method was successfully applied to the determination of Pb(II) in spiked water samples. (author)

  14. The effect of nitrate, bicarbonate and natural organic matter on the degradation of sunscreen agent p-aminobenzoic acid by simulated solar irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Liang, E-mail: lmao@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Meng, Cui; Zeng, Chao; Ji, Yuefei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Yang, Xi, E-mail: yangxi@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005 (China); Gao, Shixiang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2011-11-15

    Our experiments revealed that a model sunscreen agent, p-aminobenzoic acid (PABA), can be effectively transformed through reactions that are mediated by simulated solar irradiation. We systematically explored the effects of nitrate ions, bicarbonate and different types of natural organic matter (NOM) on the degradation of PABA by simulated solar irradiation. Experimental data suggest that these components ubiquitous in nature water have different influence on the rates of the photoinduced removal of PABA. Products were extracted and analyzed using LC/MS and a total of four products probably resulting from {center_dot}OH and {center_dot}NO{sub 2} radicals attack were identified and the possible reaction pathways were proposed. The findings in this study provide useful information for understanding the environmental transformation of sunscreen agent in aquatic system. - Highlights: {yields} In this study, we found that p-aminobenzoic acid (PABA) can be removed by simulated solar irradiation from water. {yields} Influence of environmental components on the photodegradation of PABA was further studied. {yields} We verified using LC/MS that PABA was transformed into four compounds. {yields} We proposed the possible reaction pathways probably resulting from {center_dot}OH and {center_dot}NO{sub 2} radicals attack to PABA.

  15. 2-Aminobenzamide and 2-Aminobenzoic Acid as New MALDI Matrices Inducing Radical Mediated In-Source Decay of Peptides and Proteins

    Science.gov (United States)

    Smargiasso, Nicolas; Quinton, Loic; de Pauw, Edwin

    2012-03-01

    One of the mechanisms leading to MALDI in-source decay (MALDI ISD) is the transfer of hydrogen radicals to analytes upon laser irradiation. Analytes such as peptides or proteins may undergo ISD and this method can therefore be exploited for top-down sequencing. When performed on peptides, radical-induced ISD results in production of c- and z-ions, as also found in ETD and ECD activation. Here, we describe two new compounds which, when used as MALDI matrices, are able to efficiently induce ISD of peptides and proteins: 2-aminobenzamide and 2-aminobenzoic acid. In-source reduction of the disulfide bridge containing peptide Calcitonin further confirmed the radicalar mechanism of the ISD process. ISD of peptides led, in addition to c- and z-ions, to the generation of a-, x-, and y-ions both in positive and in negative ion modes. Finally, good sequence coverage was obtained for the sequencing of myoglobin (17 kDa protein), confirming the effectiveness of both 2-aminobenzamide and 2-aminobenzoic acid as MALDI ISD matrices.

  16. 4,4′-Bipyridinium bis(perchlorate–4-aminobenzoic acid–4,4′-bipyridine–water (1/4/2/2

    Directory of Open Access Journals (Sweden)

    Qun-Hui Meng

    2009-01-01

    Full Text Available In the structure of the title compound, C10H10N22+·2ClO4−·4C7H7NO2·2C10H8N2·2H2O, the 4,4′-bipyridinium cation has a crystallographically imposed centre of symmetry. The cation is linked by N—H...N hydrogen bonds to adjacent 4,4′-bipyridine molecules, which in turn interact via O—H...N hydrogen bonds with 4-aminobenzoic acid molecules, forming chains running parallel to [30overline{2}]. The chains are further connected into a three-dimensional network by N—H...O and O—H...O hydrogen-bonding interactions involving the perchlorate anion, the water molecules and the 4-aminobenzoic acid molecules. In addition, π–π stacking interactions with centroid–centroid distances ranging from 3.663 (6 to 3.695 (6 Å are present. The O atoms of the perchlorate anion are disordered over two sets of positions, with refined site occupancies of 0.724 (9 and 0.276 (9.

  17. Hydrophilic interaction liquid chromatography of anthranilic acid-labelled oligosaccharides with a 4-aminobenzoic acid ethyl ester-labelled dextran hydrolysate internal standard.

    Science.gov (United States)

    Neville, David C A; Alonzi, Dominic S; Butters, Terry D

    2012-04-13

    Hydrophilic interaction liquid chromatography (HILIC) of fluorescently labelled oligosaccharides is used in many laboratories to analyse complex oligosaccharide mixtures. Separations are routinely performed using a TSK gel-Amide 80 HPLC column, and retention times of different oligosaccharide species are converted to glucose unit (GU) values that are determined with reference to an external standard. However, if retention times were to be compared with an internal standard, consistent and more accurate GU values would be obtained. We present a method to perform internal standard-calibrated HILIC of fluorescently labelled oligosaccharides. The method relies on co-injection of 4-aminobenzoic acid ethyl ester (4-ABEE)-labelled internal standard and detection by UV absorption, with 2-AA (2-aminobenzoic acid)-labelled oligosaccharides. 4-ABEE is a UV chromophore and a fluorophore, but there is no overlap of the fluorescent spectrum of 4-ABEE with the commonly used fluorescent reagents. The dual nature of 4-ABEE allows for accurate calculation of the delay between UV and fluorescent signals when determining the GU values of individual oligosaccharides. The GU values obtained are inherently more accurate as slight differences in gradients that can influence retention are negated by use of an internal standard. Therefore, this paper provides the first method for determination of HPLC-derived GU values of fluorescently labelled oligosaccharides using an internal calibrant. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Crystal Structure, Fluorescence Property and Theoretical Calculation of the Zn(II) Complex with o-Aminobenzoic Acid and 1,10-Phenanthroline

    International Nuclear Information System (INIS)

    Zhang, Zhongyu; Bi, Caifeng; Fan, Yuhua; Zhang, Xia; Zhang, Nan; Yan, Xingchen; Zuo, Jian

    2014-01-01

    A novel complex [Zn(phen)(o-AB) 2 ] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with a = 7.6397(6) A, b = 16.8761(18) A, c = 17.7713(19) A, α = 90 .deg., β = 98.9570(10) .deg., γ = 90 .deg., V = 2.2633(4) nm 3 , Z = 4, F(000) = 1064, S = 1.058, Dc = 1.520 g·cm -3 , R 1 = 0.0412, wR 2 = 0.0948, μ = 1.128 mm -1 . The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291

  19. The effect of nitrate, bicarbonate and natural organic matter on the degradation of sunscreen agent p-aminobenzoic acid by simulated solar irradiation

    International Nuclear Information System (INIS)

    Mao, Liang; Meng, Cui; Zeng, Chao; Ji, Yuefei; Yang, Xi; Gao, Shixiang

    2011-01-01

    Our experiments revealed that a model sunscreen agent, p-aminobenzoic acid (PABA), can be effectively transformed through reactions that are mediated by simulated solar irradiation. We systematically explored the effects of nitrate ions, bicarbonate and different types of natural organic matter (NOM) on the degradation of PABA by simulated solar irradiation. Experimental data suggest that these components ubiquitous in nature water have different influence on the rates of the photoinduced removal of PABA. Products were extracted and analyzed using LC/MS and a total of four products probably resulting from ·OH and ·NO 2 radicals attack were identified and the possible reaction pathways were proposed. The findings in this study provide useful information for understanding the environmental transformation of sunscreen agent in aquatic system. - Highlights: → In this study, we found that p-aminobenzoic acid (PABA) can be removed by simulated solar irradiation from water. → Influence of environmental components on the photodegradation of PABA was further studied. → We verified using LC/MS that PABA was transformed into four compounds. → We proposed the possible reaction pathways probably resulting from ·OH and ·NO 2 radicals attack to PABA.

  20. Synthesis, characterization and biological activity of some transition metals with Schiff base derived from 2-thiophene carboxaldehyde and aminobenzoic acid

    Science.gov (United States)

    Mohamed, Gehad G.; Omar, M. M.; Hindy, Ahmed M. M.

    2005-12-01

    Metal complexes of Schiff base derived from 2-thiophene carboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The ligand dissociation as well as the metal-ligand stability constants were calculated pH metrically at 25 °C and ionic strength μ = 0.1 (1 M NaCl). The complexes are found to have the formulae [M(HL) 2](X) n· yH 2O (where M = Fe(III) (X = Cl, n = 3, y = 3), Co(II) (X = Cl, n = 2, y = 1.5), Ni(II) (X = Cl, n = 2, y = 1) and UO 2(II) (X = NO 3, n = 2, y = 0)) and [M(L) 2] (where M = Cu(II) (X = Cl) and Zn(II) (X = AcO)). The molar conductance data reveal that Fe(III) and Co(II), Ni(II) and UO 2(II) chelates are ionic in nature and are of the type 3:1 and 2:1 electrolytes, respectively, while Cu(II) and Zn(II) complexes are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a terdentate manner with ONS donor sites of the carboxylate O, azomethine N and thiophene S. From the magnetic and solid reflectance spectra, it is found that the geometrical structure of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, Δ H*, Δ S* and Δ G* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

  1. Ligand solvation effect on Dy3+ complexing with benzoic, p-, o-, m-aminobenzoic, 4-pyridinecarboxylic acids., and with pyridine and 4-aminopyridine in aqua and aqua-organic media

    International Nuclear Information System (INIS)

    Elistratova, Yu.G.; Mustafina, A.R.; Devyatov, F.V.; Sarvarova, N.N.

    1996-01-01

    Substituent effect on stability of Dy 3+ complexes with aminobenzoic acids (o , p-, m-isomers), pyridinecarboxylic acids and p-aminopyridine was estimated on the base of pH-metric and magnetooptic data. It was concluded that the more the efficiency of ligand's solvation the less the substituent effects the complex stability. 15 refs., 3 figs., 2 tabs

  2. Para-aminobenzoic acid

    Science.gov (United States)

    PABA is used in certain sunscreen and skin-care products. It may also naturally occur in these foods: Brewer's yeast Liver Molasses Mushrooms Spinach Whole grains Other products may also contain PABA.

  3. Crystal structures of two erbium(III complexes with 4-aminobenzoic acid and 4-chloro-3-nitrobenzoic acid

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2015-12-01

    Full Text Available The crystal structures of two erbium(III complexes with 4-aminobenzoic acid (4-ABAH, namely bis(μ2-4-aminobenzoato-κ2O:O′bis[bis(4-aminobenzoato-κ2O,O′diaquaerbium(III] dihydrate, [Er2(C7H6NO26(H2O4]·2H2O, (I, and 4-chloro-3-nitrobenzoic acid (CLNBAH, namely poly[hexakis(μ2-4-chloro-3-nitrobenzoato-κ2O:O′bis(dimethyl sulfoxide-κOdierbium(III], [Er2(C7H3ClNO46(C2H6OS2]n, (II, have been determined. In the structure of solvatomorphic compound (I, the symmetry-related irregular ErO8 coordination polyhedra in the discrete centrosymmetric dinuclear complex comprise two monodentate water molecules and six carboxylate O-atom donors, four from two bidentate carboxylate O,O′-chelate groups and two from the bis-monodentate O:O′-bridging group of the third 4-ABA anion. The Er—O bond-length range is 2.232 (3–2.478 (3 Å and the Er...Er separation in the dinuclear complex unit is 4.7527 (4 Å. One of the coordinating water molecules is involved in an intra-unit O—H...O hydrogen-bonding association with an inversion-related carboxylate O-atom acceptor. In contrast, the anhydrous compound (II is polymeric, based on centrosymmetric dinuclear repeat units comprising ErO7 coordination polyhedra which involve four O-atom donors from two bidentate O:O′-bridging carboxylate groups, one O-atom donor from the monodentate dimethyl sulfoxide ligand and two O-atom donors from the third bridging CLNBA anion. The latter provides the inter-unit link in the one-dimensional coordination polymer extending along [100]. The Er—O bond-length range in (II is 2.239 (6–2.348 (6 Å and the Er...Er separation within the dinuclear unit is 4.4620 (6 Å. In the crystal of (I, extensive inter-dimer O—H...O and N—H...O hydrogen-bonding interactions involving both the coordinating water molecules and the solvent water molecules, as well as the amine groups of the 4-ABA anions, give an overall three-dimensional network structure. Within

  4. Para-aminobenzoic acid (PABA) used as a marker for completeness of 24 hour urine: effects of age and dosage scheduling

    DEFF Research Database (Denmark)

    Jakobsen, J.; Pedersen, Agnes Nadelmann; Ovesen, L.

    2003-01-01

    collections in this age group will be rejected unjustly (false-negatives). Also, with the currently recommended dosage schedule (PABA taken with the main meals) the risk of false-positive 24 h urine collections prevails. With refinement of the PABA test procedure, ie employing a specific analytical method......Objective: To examine the age dependency of the urinary para-aminobenzoic acid (PABA) excretion, and if a delayed PABA excretion can be overcome by advancing intake schedule; and to examine the recovery of PABA in fractionated urinary samples collected during 24 h after single and repeated doses...... specimens for 24 h after a morning dose of 80 mg of PABA, and another subgroup of 10 subjects collected individual urine specimens for 24 h after ingestion of 80 mg of PABA three times at mealtimes. Subjects: Employees and relatives from the Danish Food Administration. Setting: Ninety-nine healthy...

  5. Studies on molecular structure, vibrational spectra and molecular docking analysis of 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate

    Science.gov (United States)

    Suresh, D. M.; Amalanathan, M.; Hubert Joe, I.; Bena Jothy, V.; Diao, Yun-Peng

    2014-09-01

    The molecular structure, vibrational analysis and molecular docking analysis of the 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate (MDDNAB) molecule have been carried out using FT-IR and FT-Raman spectroscopic techniques and DFT method. The equilibrium geometry, harmonic vibrational wave numbers, various bonding features have been computed using density functional method. The calculated molecular geometry has been compared with experimental data. The detailed interpretation of the vibrational spectra has been carried out by using VEDA program. The hyper-conjugative interactions and charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The simulated FT-IR and FT-Raman spectra satisfactorily coincide with the experimental spectra. The PES and charge analysis have been made. The molecular docking was done to identify the binding energy and the Hydrogen bonding with the cancer protein molecule.

  6. Comparison of hydrogen isotope exchange reactions between HTO vapor and the sodium salts of o-, m-, and p-aminobenzoic acid

    International Nuclear Information System (INIS)

    Okada, Minoru; Imaizumi, Hiroshi; Itoh, Tomoko

    1991-01-01

    Hydrogen isotope exchange reaction between HTO vapor and one of the sodium salts of o-, m-, and p-aminobenzoic acid (solid) was observed at 50 ∼ 80 degC. The acidity (acidity based on kinetic logic) for the materials at each temperature has been obtained with the A''-McKay plots based on the respective data obtained. The followings have been clarified by comparing these acidities (and the acidities obtained previously). 1) The acidity of aromatic amines can be expressed in terms of the acidity based on kinetic logic. 2) The reactivity of aromatic amine is strongly affected by both I-effect and R-effect. 3) It can be deduced that aromatic amines are more reactive than aliphatic amines. (author)

  7. Electrochemical behavior and voltammetric determination of acetaminophen based on glassy carbon electrodes modified with poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite films

    International Nuclear Information System (INIS)

    Zhu, Wencai; Huang, Hui; Gao, Xiaochun; Ma, Houyi

    2014-01-01

    Poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite film modified glassy carbon electrodes (4-ABA/ERGO/GCEs) were fabricated by a two-step electrochemical method. The electrochemical behavior of acetaminophen at the modified electrode was investigated by means of cyclic voltammetry. The results indicated that 4-ABA/ERGO composite films possessed excellent electrocatalytic activity towards the oxidation of acetaminophen. The electrochemical reaction of acetaminophen at 4-ABA/ERGO/GCE is proved to be a surface-controlled process involving the same number of protons and electrons. The voltammetric determination of acetaminophen performed with the 4-ABA/ERGO modified electrode presents a good linearity in the range of 0.1–65 μM with a low detection limit of 0.01 μM (S/N = 3). In the case of using the 4-ABA/ERGO/GCE, acetaminophen and dopamine can be simultaneously determined without mutual interference. Furthermore, the 4-ABA/ERGO/GCE has good reproducibility and stability, and can be used to determine acetaminophen in tablets. - Highlights: • The 4-ABA/ERGO/GCE was fabricated by a two-step electrochemical method. • Electrochemical behavior of acetaminophen at the 4-ABA/ERGO/GCE was investigated. • The electrochemical sensor exhibited a low detection limit and good selectivity. • This sensor was applied to the detection of acetaminophen in commercial tablets

  8. Electrochemical behavior and voltammetric determination of acetaminophen based on glassy carbon electrodes modified with poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite films

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wencai [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); School of Chemistry and Chemical Engineering, Qilu Normal University, Jinan 250013 (China); Huang, Hui; Gao, Xiaochun [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Ma, Houyi, E-mail: hyma@sdu.edu.cn [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2014-12-01

    Poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite film modified glassy carbon electrodes (4-ABA/ERGO/GCEs) were fabricated by a two-step electrochemical method. The electrochemical behavior of acetaminophen at the modified electrode was investigated by means of cyclic voltammetry. The results indicated that 4-ABA/ERGO composite films possessed excellent electrocatalytic activity towards the oxidation of acetaminophen. The electrochemical reaction of acetaminophen at 4-ABA/ERGO/GCE is proved to be a surface-controlled process involving the same number of protons and electrons. The voltammetric determination of acetaminophen performed with the 4-ABA/ERGO modified electrode presents a good linearity in the range of 0.1–65 μM with a low detection limit of 0.01 μM (S/N = 3). In the case of using the 4-ABA/ERGO/GCE, acetaminophen and dopamine can be simultaneously determined without mutual interference. Furthermore, the 4-ABA/ERGO/GCE has good reproducibility and stability, and can be used to determine acetaminophen in tablets. - Highlights: • The 4-ABA/ERGO/GCE was fabricated by a two-step electrochemical method. • Electrochemical behavior of acetaminophen at the 4-ABA/ERGO/GCE was investigated. • The electrochemical sensor exhibited a low detection limit and good selectivity. • This sensor was applied to the detection of acetaminophen in commercial tablets.

  9. Validated RP-HPLC/DAD Method for the Quantification of Insect Repellent Ethyl 2-Aminobenzoate in Membrane-Moderated Matrix Type Monolithic Polymeric Device.

    Science.gov (United States)

    Islam, Johirul; Zaman, Kamaruz; Chakrabarti, Srijita; Sharma Bora, Nilutpal; Mandal, Santa; Pratim Pathak, Manash; Srinivas Raju, Pakalapati; Chattopadhyay, Pronobesh

    2017-07-01

    A simple, accurate and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for the estimation of ethyl 2-aminobenzoate (EAB) in a matrix type monolithic polymeric device and validated as per the International Conference on Harmonization guidelines. The analysis was performed isocratically on a ZORBAX Eclipse plus C18 analytical column (250 × 4.4 mm, 5 μm) and a diode array detector (DAD) using acetonitrile and water (75:25 v/v) as the mobile phase by keeping the flow-rate constant at 1.0 mL/min. Determination of EAB was not interfered in the presence of excipients. Inter- and intra-day relative standard deviations were not higher than 2%. Mean recovery was between 98.7 and 101.3%. Calibration curve was linear in the concentration range of 0.5-10 µg/mL. Limits of detection and quantification were 0.19 and 0.60 µg/mL, respectively. Thus, the present report put forward a novel method for the estimation of EAB, an emerging insect repellent, by using RP-HPLC technique. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Electrochemical behavior and voltammetric determination of acetaminophen based on glassy carbon electrodes modified with poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite films.

    Science.gov (United States)

    Zhu, Wencai; Huang, Hui; Gao, Xiaochun; Ma, Houyi

    2014-12-01

    Poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite film modified glassy carbon electrodes (4-ABA/ERGO/GCEs) were fabricated by a two-step electrochemical method. The electrochemical behavior of acetaminophen at the modified electrode was investigated by means of cyclic voltammetry. The results indicated that 4-ABA/ERGO composite films possessed excellent electrocatalytic activity towards the oxidation of acetaminophen. The electrochemical reaction of acetaminophen at 4-ABA/ERGO/GCE is proved to be a surface-controlled process involving the same number of protons and electrons. The voltammetric determination of acetaminophen performed with the 4-ABA/ERGO modified electrode presents a good linearity in the range of 0.1-65 μM with a low detection limit of 0.01 μM (S/N=3). In the case of using the 4-ABA/ERGO/GCE, acetaminophen and dopamine can be simultaneously determined without mutual interference. Furthermore, the 4-ABA/ERGO/GCE has good reproducibility and stability, and can be used to determine acetaminophen in tablets. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. 4-({(Z-5-[(Z-3-Ethoxy-4-hydroxybenzylidene]-3-methyl-4-oxo-1,3-thiazolidin-2-ylidene}aminobenzoic acid dimethylformamide monosolvate

    Directory of Open Access Journals (Sweden)

    Paul Kosma

    2012-12-01

    Full Text Available The molecular structure of the title compound, C20H18N2O5S·C3H7NO, represents an essentially planar 5-benzylidene-thiazolidine moiety (r.m.s. deviation from planarity without ring substituents = 0.095 Å to which the 4-aminobenzoic acid fragment is inclined at 76.23 (1°. In the crystal, the benzoic acid molecules are arranged in layers parallel to [001] which are built up from inversion dimers held together by head-to-tail phenol–carboxy O—H...O hydrogen bonds and head-to-tail π–π stacking interactions between the 5-benzylidene-thiazolidine moieties (ring centroid distance = 3.579 Å. These layers are separated by the dimethylformamide solvent molecules which are firmly anchored via a short O—H...O hydrogen bond [O...O = 2.5529 (10 Å] donated by the –COOH group.

  12. Quantitative twoplex glycan analysis using 12C6 and 13C6 stable isotope 2-aminobenzoic acid labelling and capillary electrophoresis mass spectrometry.

    Science.gov (United States)

    Váradi, Csaba; Mittermayr, Stefan; Millán-Martín, Silvia; Bones, Jonathan

    2016-12-01

    Capillary electrophoresis (CE) offers excellent efficiency and orthogonality to liquid chromatographic (LC) separations for oligosaccharide structural analysis. Combination of CE with high resolution mass spectrometry (MS) for glycan analysis remains a challenging task due to the MS incompatibility of background electrolyte buffers and additives commonly used in offline CE separations. Here, a novel method is presented for the analysis of 2-aminobenzoic acid (2-AA) labelled glycans by capillary electrophoresis coupled to mass spectrometry (CE-MS). To ensure maximum resolution and excellent precision without the requirement for excessive analysis times, CE separation conditions including the concentration and pH of the background electrolyte, the effect of applied pressure on the capillary inlet and the capillary length were evaluated. Using readily available 12/13 C 6 stable isotopologues of 2-AA, the developed method can be applied for quantitative glycan profiling in a twoplex manner based on the generation of extracted ion electropherograms (EIE) for 12 C 6 'light' and 13 C 6 'heavy' 2-AA labelled glycan isotope clusters. The twoplex quantitative CE-MS glycan analysis platform is ideally suited for comparability assessment of biopharmaceuticals, such as monoclonal antibodies, for differential glycomic analysis of clinical material for potential biomarker discovery or for quantitative microheterogeneity analysis of different glycosylation sites within a glycoprotein. Additionally, due to the low injection volume requirements of CE, subsequent LC-MS analysis of the same sample can be performed facilitating the use of orthogonal separation techniques for structural elucidation or verification of quantitative performance.

  13. 4-Aminobenzoic Acid-Coated Maghemite Nanoparticles as Potential Anticancer Drug Magnetic Carriers: A Case Study on Highly Cytotoxic Cisplatin-Like Complexes Involving 7-Azaindoles

    Directory of Open Access Journals (Sweden)

    Pavel Štarha

    2014-01-01

    Full Text Available This study describes a one-pot synthesis of superparamagnetic maghemite-based 4-aminobenzoic acid-coated spherical core-shell nanoparticles (PABA@FeNPs as suitable nanocomposites potentially usable as magnetic carriers for drug delivery. The PABA@FeNPs system was subsequently functionalized by the activated species (1* and 2* of highly in vitro cytotoxic cis-[PtCl2(3Claza2] (1; 3Claza stands for 3-chloro-7-azaindole or cis-[PtCl2(5Braza2] (2; 5Braza stands for 5-bromo-7-azaindole, which were prepared by a silver(I ion assisted dechlorination of the parent dichlorido complexes. The products 1*@PABA@FeNPs and 2*@PABA@FeNPs, as well as an intermediate PABA@FeNPs, were characterized by a combination of various techniques, such as Mössbauer, FTIR and EDS spectroscopy, thermal analysis, SEM and TEM. The results showed that the products consist of well-dispersed maghemite-based nanoparticles of 13 nm average size that represent an easily obtainable system for delivery of highly cytotoxic cisplatin-like complexes in oncological practice.

  14. DFT calculations, spectroscopic, thermal analysis and biological activity of Sm(III) and Tb(III) complexes with 2-aminobenzoic and 2-amino-5-chloro-benzoic acids

    Science.gov (United States)

    Essawy, Amr A.; Afifi, Manal A.; Moustafa, H.; El-Medani, S. M.

    2014-10-01

    The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed.

  15. Nanopore Long-Read Guided Complete Genome Assembly of Hydrogenophaga intermedia, and Genomic Insights into 4-Aminobenzenesulfonate, p-Aminobenzoic Acid and Hydrogen Metabolism in the Genus Hydrogenophaga.

    Science.gov (United States)

    Gan, Han M; Lee, Yin P; Austin, Christopher M

    2017-01-01

    We improved upon the previously reported draft genome of Hydrogenophaga intermedia strain PBC, a 4-aminobenzenesulfonate-degrading bacterium, by supplementing the assembly with Nanopore long reads which enabled the reconstruction of the genome as a single contig. From the complete genome, major genes responsible for the catabolism of 4-aminobenzenesulfonate in strain PBC are clustered in two distinct genomic regions. Although the catabolic genes for 4-sulfocatechol, the deaminated product of 4-aminobenzenesulfonate, are only found in H. intermedia , the sad operon responsible for the first deamination step of 4-aminobenzenesulfonate is conserved in various Hydrogenophaga strains. The absence of pabB gene in the complete genome of H. intermedia PBC is consistent with its p -aminobenzoic acid (pABA) auxotrophy but surprisingly comparative genomics analysis of 14 Hydrogenophaga genomes indicate that pABA auxotrophy is not an uncommon feature among members of this genus. Of even more interest, several Hydrogenophaga strains do not possess the genomic potential for hydrogen oxidation, calling for a revision to the taxonomic description of Hydrogenophaga as "hydrogen eating bacteria."

  16. Chemical Speciation and Bond Lengths of Organic Solutes by Core-Level Spectroscopy: pH and Solvent Influence on p-Aminobenzoic Acid.

    Science.gov (United States)

    Stevens, Joanna S; Gainar, Adrian; Suljoti, Edlira; Xiao, Jie; Golnak, Ronny; Aziz, Emad F; Schroeder, Sven L M

    2015-05-04

    Through X-ray absorption and emission spectroscopies, the chemical, electronic and structural properties of organic species in solution can be observed. Near-edge X-ray absorption fine structure (NEXAFS) and resonant inelastic X-ray scattering (RIXS) measurements at the nitrogen K-edge of para-aminobenzoic acid reveal both pH- and solvent-dependent variations in the ionisation potential (IP), 1s→π* resonances and HOMO-LUMO gap. These changes unequivocally identify the chemical species (neutral, cationic or anionic) present in solution. It is shown how this incisive chemical state sensitivity is further enhanced by the possibility of quantitative bond length determination, based on the analysis of chemical shifts in IPs and σ* shape resonances in the NEXAFS spectra. This provides experimental access to detecting even minor variations in the molecular structure of solutes in solution, thereby providing an avenue to examining computational predictions of solute properties and solute-solvent interactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Portable electrochemical sensor based on 4-aminobenzoic acid-functionalized herringbone carbon nanotubes for the determination of ascorbic acid and uric acid in human fluids.

    Science.gov (United States)

    Abellán-Llobregat, A; González-Gaitán, C; Vidal, L; Canals, A; Morallón, E

    2018-06-30

    A new portable electrochemical sensor based on 4-aminobenzoic acid-modified herringbone carbon nanotubes (hCNTs-4ABA/Au-IDA) has been developed for the simultaneous determination of ascorbic acid (AA) and uric acid (UA) in physiological fluids. AA and UA were quantified by chronoamperometry at 0.1 and 0.32 V, respectively, in phosphate buffer solution (PBS 0.25 M, pH 7.0). Significant results were obtained for the separate quantification of AA and UA, with a limit of detection (LOD) of 0.65 μM for both analytes, and sensitivities of (9.0 ± 0.4) A g -1 mM -1 and (8.8 ± 0.3) A g -1 mM -1 for AA and UA, respectively. Repeatability was studied at 50 μM for AA and UA, providing relative standard deviations (RSD) lower than 9%. Additions of glucose, dopamine and epinephrine did not interfere with the AA and UA determination. Furthermore, UA did not interfere with AA determination at 0.1 V, although AA additions increased the current recorded at 0.32 V. The method has been successfully applied to human urine, perspiration and serum samples, without significant matrix effects, which allows for the use of an external calibration and the analysis of all the matrices investigated. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. [Analysis of monosaccharides and uronic acids in polysaccharides by pre-column derivatization with p-aminobenzoic acid and high performance liquid chromatography].

    Science.gov (United States)

    Hao, Guitang; Chen, Shangwei; Zhu, Song; Yin, Hongping; Dai, Jun; Cao, Yuhua

    2007-01-01

    An ion-pair reversed-phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of carbohydrate and uronic acids was developed. p-Aminobenzoic acid (p-AMBA) was used for pre-column derivatization of the analytes, enabling fluorescence (lambda(ex) = 313 nm, lambda(em) = 358 nm) or ultraviolet (UV at 303 nm) detection. Reaction conditions such as reaction temperature and reaction time were optimized. Atlantis dC18 column with hydrophilic end capping was selected for the separation of derivatives. Effects of mobile phase compositions such as ion pairs and their concentrations and pH on the retention behaviors and separation results of 9 monosaccharides and 2 uronic acids were investigated. Derivatives of fructose, galactose, glucose, mannose, xylose, arabinose, ribose, galacturonic acid, fucose, glucuronic acid and rhamnose were separated within 42 min, applying tetrabutyl ammonium hydrogen bisulfate (TBAHSO4) as the ion pair reagent. The detection limits were between 3.38 x 10(-8) mol/L and 176 x 10(-8) mol/L for fluorescence detection and between 2.55 x 10(-7) mol/L and 13.4 x 10(-7) mol/L for UV detection. Good linearities were obtained with correlation coefficients (r2) above 0.99. The relative standard deviations (RSDs) of the peak area of the derivatives in 12 - 51 h after derivatization were from 2.5% to 3.9%. This method has been applied for the determination of mono-/disaccharides and uronic acids in spirulina polysaccharide after dissolved in trifluoroacetic acid solution (2 mol/L). The results showed this method is suitable for the analysis of monosaccharide compositions in polysaccharides.

  19. The Efficacy of Medical Treatment of Peyronie’s Disease: Potassium Para-Aminobenzoate Monotherapy vs. Combination Therapy with Tamoxifen, L-Carnitine, and Phosphodiesterase Type 5 Inhibitor

    Directory of Open Access Journals (Sweden)

    Tae Yong Park

    2016-04-01

    Full Text Available Purpose: This study was designed to evaluate the efficacy of medical treatment of Peyronie’s disease. Materials and Methods: A total of 109 patients with Peyronie’s disease who had been treated from January 2011 to December 2014 were retrospectively reviewed in this study. Forty-four patients (Group 1 were treated with 12 mg of potassium para-aminobenzoate daily. Sixty-five patients (Group 2 were treated with combination therapy: tamoxifen (20 mg and acetyl-L-carnitine (300 mg twice daily in addition to a phosphodiesterase type 5 inhibitor. Ability to perform sexual intercourse, pain during erection, size of plaque, and penile curvature angle were assessed. Results: In Group 1, 30 of 44 patients (68.2% discontinued treatment within 12 weeks, while 5 patients (7.7% in Group 2 discontinued treatment. Pain during erection and plaque size were improved in both groups but showed no statistical difference due to the high dropout rate in Group 1. In both groups, penile curvature was improved, but demonstrated no statistical difference between the treatment groups. However, combination therapy demonstrated a better response rate in patients whose penile curvature angle was less than 30o (44.4% vs. 79.1%, p=0.048. The rate of successful sexual intercourse was significantly higher in Group 2 (42.8% vs. 78.3%, p=0.034. The number of patients who underwent surgical correction despite medical treatment was significantly higher in Group 1 (35.7% vs. 13.3%, p=0.048. Conclusions: Early medical combination therapy in Peyronie’s disease may present better results in patients whose curvature angle is less than 30o.

  20. Quantum chemical calculations and experimental investigations on 2-aminobenzoic acid-cyclodiphosph(V)azane derivative and its homo-binuclear Cu(II) complex

    Science.gov (United States)

    El-Gogary, Tarek M.; Alaghaz, Abdel-Nasser M. A.; Ammar, Reda A. A.

    2012-03-01

    A novel 2-aminobenzoic acid-cyclodiphosph(V)azane ligand H4L and its homo-binuclear Cu(II) complex of the type [Cu2L(H2O)2].2.5 H2O in which L is 1,3-di(-o-pyridyl)-2,4-(dioxo)-2',4'-bis-(2-iminobenzoic acid) cyclodiphosph(V)azane, were synthesized and characterized by different physical techniques. Infrared spectra of the complex indicate deprotonation and coordination of the imine NH and carboxyl COOH groups. It also confirms that nitrogen atom of the pyridine ring contribute to the complexation. Electronic spectra and magnetic susceptibility measurements reveal square-planar geometry for the Cu(II) complex. The elemental analyses and thermogravimetric results have justified the [Cu2L(H2O)2]·2.5H2O composition of the complex. Quantum chemical calculations were utilized to explore the electronic structure and stability of the H4L as well as the binuclear Cu(II) complex. Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of H4L and its binuclear Cu(II) complex. Different tautomers and geometrical isomers of the ligand were optimized at the ab initio DFT level. Simulated IR frequencies were scaled and compared with that experimentally measured. TD-DFT method was used to compute the UV-VIS spectra which show good agreement with measured electronic spectra.

  1. The effects of dissolved organic matter and feeding on bioconcentration and oxidative stress of ethylhexyl dimethyl p-aminobenzoate (OD-PABA) to crucian carp (Carassius auratus).

    Science.gov (United States)

    Ma, Binni; Lu, Guanghua; Yang, Haohan; Liu, Jianchao; Yan, Zhenhua; Nkoom, Matthew

    2018-03-01

    Bioconcentration of UV filters in organisms is an important indicator for the assessment of environmental hazards. However, bioconcentration testing rarely accounts for the influence of natural aquatic environmental factors. In order to better assess the ecological risk of organic UV filters (OUV-Fs) in an actual water environment, this study determined the influences of dissolved organic matter (DOM) (0, 1, 10, and 20 mg/L) and feeding (0, 0.5, 1, and 2% body weight/d) on bioconcentration of ethylhexyl dimethyl p-aminobenzoate (OD-PABA) in various tissues of crucian carp (Carassius auratus). Moreover, oxidative stress in the fish liver caused by the OD-PABA was also investigated by measuring activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST), and levels of glutathione (GSH) and malondialdehyde (MDA). The bioconcentration of OD-PABA in the fish tissues was significantly decreased with the presence of DOM indicating a reduction of OD-PABA bioavailability caused by DOM. The bioconcentration factors (BCFs) decreased by 28.00~50.93% in the muscle, 72.67~96.74% in the gill, 37.84~87.72% in the liver, and 10.32~79.38% in the kidney at different DOM concentrations compared to those of the non-DOM treatments. Significant changes in SOD, CAT, GST, GSH, and MDA levels were found in the DOM- and OD-PABA-alone treatments. However, there were no significant differences in the SOD, CAT, GST, and MDA levels found when co-exposure to OD-PABA and DOM. Feeding led to lower OD-PABA concentrations in the fish tissues, and the concentrations were decreased with increasing feeding ratios. BCFs in various tissues reduced by 39.75~72.52% in the muscle, 56.86~79.73% in the gill, 66.41~87.50% in the liver, and 75.88~89.10% in the kidney, respectively. In the unfed treatments, the levels of SOD and MDA were significantly higher than those of the fed ones while GST and GSH levels were remarkably inhibited indicating the enhanced effect of starvation

  2. Rigid, non-porous and tunable hybrid p-aminobenzoate/TiO2 materials: Toward a fine structural determination of the immobilized RhCl(Ph3)3 complex

    KAUST Repository

    Espinas, Jeff

    2015-05-01

    By exchange of ligands, Wilkinson complex RhCl(PPh3)3 are immobilized on p-aminobenzoate/TiO2 with different organic loading (6, 11 and 16%). This new hybrid material exhibit a linear correlation between the ligand content of the starting TiO2 and the rhodium loading, showing the accessibility of all surfaces amines fonctions on the non-porous parent materials. 1H, 13C, and 1D, 2D INAQUEDATE refocused and J-resolved 31P solid-state NMR confirm the well-defined structure [(≡TiO)2(n{right tail}2-O2C-C6H4-NH2)RhCl-cis-(PPh3)2]. New immobilized catalysts show interesting activity in cyclohexene hydroformylation.

  3. Rigid, non-porous and tunable hybrid p-aminobenzoate/TiO2 materials: Toward a fine structural determination of the immobilized RhCl(Ph3)3 complex

    KAUST Repository

    Espinas, Jeff; Rahal, Raed; Abou-Hamad, Edy; El Eter, Mohamad; Basset, Jean-Marie

    2015-01-01

    By exchange of ligands, Wilkinson complex RhCl(PPh3)3 are immobilized on p-aminobenzoate/TiO2 with different organic loading (6, 11 and 16%). This new hybrid material exhibit a linear correlation between the ligand content of the starting TiO2 and the rhodium loading, showing the accessibility of all surfaces amines fonctions on the non-porous parent materials. 1H, 13C, and 1D, 2D INAQUEDATE refocused and J-resolved 31P solid-state NMR confirm the well-defined structure [(≡TiO)2(n{right tail}2-O2C-C6H4-NH2)RhCl-cis-(PPh3)2]. New immobilized catalysts show interesting activity in cyclohexene hydroformylation.

  4. Electrochemical behavior and assembly of tetranuclear Dawson-derived sandwich compound [Cd4(H2O)2(As2W15O56)2]16- on 4-aminobenzoic acid modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Bi Lihua; Shen Yan; Jiang Junguang; Wang Erkang; Dong Shaojun

    2005-01-01

    The transition metal-substituted heteropolyoxoanion, Cd 4 (H 2 O) 2 (As 2 W 15 O 56 ) 2 12- (As 4 W 30 Cd 4 ), is one of the trivacant Dawson derivatives. Its redox electrochemistry has been studied in acid buffer solutions using cyclic voltammetry. It exhibited three steps of four-electron redox waves attributed to redox processes of the tungsten-oxo framework. Through layer-by-layer assembly, the compound was first successfully immobilized on a 4-aminobenzoic acid modified glassy carbon electrode surface by alternate deposition with a quaternized poly(4-vinylpyridine) partially complexed with [Os(bpy) 2 Cl] 2+/+ (denoted as QPVP-Os). Thus, prepared multilayer films have been characterized by cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy (UV-vis). The electrocatalytic activities of the multilayer films containing As 4 W 30 Cd 4 have been investigated on the reduction of three substrates of important analytical interests, NO 2 - , BrO 3 - and IO 3 - . And with the increase of the number of As 4 W 30 Cd 4 layers, the catalytic current towards the reduction of BrO 3 - was enhanced and the catalytic potential shifted positively

  5. Crystal structures of palladium(II) ternary complexes of 5-x-2-aminobenzoic acid with 1,10-phenanthroline and their interaction with calf thymus DNA (where X=Cl, Br and I).

    Science.gov (United States)

    Wang, Yue; Okabe, Nobuo; Odoko, Mamiko

    2005-10-01

    The crystal structures of a series of three palladium(II) ternary complexes of 5-halogeno-2-aminobenzoic acid (5-X-AB, where X=Cl, Br and I) with 1,10-phenanthroline [Pd(5-Cl-AB)(phen)] (1), [Pd(5-Br-AB)(phen)] (2) and [Pd(5-I-AB)(phen)] (3) have been determined, and their coordination geometries and the crystal architecture characterized. All of the complexes are an isostructure in which each Pd(II) atom has basically similar square planar coordination geometry. The substitute halogen group at 5-position of AB plays an important role in producing the coordination bonds of the carboxylate and amino groups in which the carboxylate O atom and the amino N atom act as the negative monodentate ligand atoms. The coordination bond distances of O-Pd increase in the order 1<2<3, while those of N-Pd decrease in the same order. The binding of the complexes to the calf thymus DNA has also been studied by the fluorescence method. Each of the complexes shows high binding propensity to DNA which can be reflected as the relative order 1<2<3.

  6. Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: Synthesis, spectral characterization, antimicrobial and nuclease studies

    Science.gov (United States)

    Subbaraj, P.; Ramu, A.; Raman, N.; Dharmaraja, J.

    2014-01-01

    A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA = Schiff base and B = 2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, 1H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, 1H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique.

  7. Transplacental passage of Pt after treatment with the new triamine complex cis-diaminechloro-[2-(diethylamino) ethyl 4-amino-benzoate, N{sup 4}]-chloride platinum (II) monohydrochloride monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Ognio, Emanuela; Lapide, Maddalena [Servizio Modelli Animali, Istituto Nazionale per la Ricerca sul Cancro, Genova (Italy); Chiavarina, Barbara; Viale, Maurizio [U.O. Farmacologia e Neuroscienze, Lab. Farmacologia Tossicologica, Istituto Nazionale per la Ricerca sul Cancro, Lgo R. Benzi, 10, Genova (Italy); Caviglioli, Gabriele [Universita di Genova, Dipartimento di Chimica e Tecnologie Farmaceutiche e Alimentari, Genova (Italy)

    2004-10-01

    Cis-diaminechloro-[2-(diethylamino) ethyl 4-amino-benzoate, N{sup 4}]-chloride platinum (II) monohydrochloride monohydrate (DPR) is a monofunctional Pt triamine complex synthesized starting from cisplatin and procaine hydrochloride, characterized by a good antitumor activity coupled with low toxic effects and able to impair prenatal development of mice but at doses outside or just in the upper range of therapeutic doses. In the present paper the transplacental passage of DPR-derived Pt was investigated in CD1 mice on days 9, 13, 16 and 18 of pregnancy, 24 h after ip administration of 21 mg/kg DPR. For comparison, groups of mice were treated with an equivalent Pt-containing dose of cisplatin (10.7 mg/kg). Similarly to cisplatin, small amounts of Pt were detected in fetuses on day 9. From day 13 of gestation the concentration of DPR- and cisplatin-derived Pt increased up to the highest fetal concentrations detected on day 16. On day 18 the concentration of Pt decreased. Most importantly, on days 13-18 of pregnancy cisplatin-derived Pt was always significantly higher than that assayed after DPR administration. In addition, on day 13 of pregnancy Pt exposure of fetuses was significantly higher when dams were treated with cisplatin (AUC{sub 0.5-24}= 3.40 vs. 4.95 {mu}g.h/g). Finally, it is worth noting that serum decay of Pt after DPR or cisplatin administration in adult female mice was similar with AUC{sub 0.13-2h} s of 7.5 and 6.6 {mu}g.h/ml, respectively. When we determined the concentration of Pt into the main organs of fetuses from dams treated with either DPR or cisplatin on day 18 of gestation, we observed a different organ distribution. In fact, while the concentration of DPR-derived Pt was greater in the heart (1.08{+-}0.30 vs. 0.78{+-}0.35 {mu}g/g, p<0.10), an opposite situation was found in the kidney (0.51{+-}0.20 vs. 0.69{+-}0.22 {mu}g/g, p<0.05). In conclusion, our data show that DPR may pass through the placenta with an efficiency significantly lower than

  8. Crystal structures of three anhydrous salts of the Lewis base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU with the ring-substituted benzoic acid analogues 4-aminobenzoic acid, 3,5-dinitrobenzoic acid and 3,5-dinitrosalicylic acid

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2016-03-01

    Full Text Available The anhydrous salts of the Lewis base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU with 4-aminobenzoic acid [1-aza-8-azoniabicyclo[5.4.0]undec-7-ene 4-aminobenzoate, C9H17N2+·C7H6NO2− (I], 3,5-dinitrobenzoic acid [1-aza-8-azoniabicyclo[5.4.0]undec-7-ene 3,5-dinitrobenzoate, C9H17N2+·C7H3N2O6−, (II] and 3,5-dinitrosalicylic acid (DNSA [1-aza-8-azoniabicyclo[5.4.0]undec-7-ene 2-hydroxy-3,5-dinitrobenzoate, C9H17N2+·C7H3N2O7−, (III] have been determined and their hydrogen-bonded structures are described. In both (II and (III, the DBU cations have a common disorder in three of the C atoms of the six-membered ring moieties [site-occupancy factors (SOF = 0.735 (3/0.265 (3 and 0.686 (4/0.314 (4, respectively], while in (III, there is additional rotational disorder in the DNSA anion, giving two sites (SOF = 0.72/0.28, values fixed for the phenol group. In the crystals of (I and (III, the cation–anion pairs are linked through a primary N—H...Ocarboxyl hydrogen bond [2.665 (2 and 2.869 (3 Å, respectively]. In (II, the ion pairs are linked through an asymmetric three-centre R12(4, N—H...O,O′ chelate association. In (I, structure extension is through amine N—H...Ocarboxyl hydrogen bonds between the PABA anions, giving a three-dimensional structure. The crystal structures of (II and (III are very similar, the cation–anion pairs being associated only through weak C—H...O hydrogen bonds, giving in both overall two-dimensional layered structures lying parallel to (001. No π–π ring associations are present in any of the structures.

  9. Crystal and molecular structure of dysprosium (3) n-aminobenzoate

    International Nuclear Information System (INIS)

    Khiyalov, M.S.; Amiraslanov, I.R.; Mamedov, Kh.S.; Movsumov, Eh.M.

    1981-01-01

    The X ray diffraction investigation of the Dy(NH 2 C 6 H 4 COO) 3 x3H 2 O complex is carried out. Triclinic crystals have lattice parameters α=11.095(15), b=9.099(17), c=12.780 (15)A, α=108.051(12), β=89.072(10); γ=104.954(12) 0 , space group P anti 1, Z=2. The structure consists of dimer molecules. The third water molecule in the formula is an outer spherical one. The average lengths of Dy-O and Dy-OH 2 are 2.39 and 2.40 A respectively, the average value of Dy-O in bridge carboxylates (2.26A) is remarkably shorter. Hydrogen bonds between amine ligand ends, carboxylic groups oxygen and water molecules bind complex molecules into the three-dimensional frame [ru

  10. 4-Aminobenzoic acid 4-methylpyridine/4-methylpyridinium 4-aminobenzoate 0.58/0.42: a redetermination from the original data

    Czech Academy of Sciences Publication Activity Database

    Fábry, Jan

    2017-01-01

    Roč. 73, Oct (2017), s. 1508-1512 ISSN 2056-9890 R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : crystal structure * hydrogen bonding * symmetric hydrogen bonds * refinement constraints Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry

  11. Poly (aniline-co-m-aminobenzoic acid) deposited on poly (vinyl ...

    Indian Academy of Sciences (India)

    The composite film was characterized by Fourier transform infra red (FT–IR) and ultraviolet visible (UV–VIS) spectroscopy and electrical measurements. Surface morphology of the composite films was studied by field emission scanning electron microscopy (FESEM). The variation of conductivity of the films was studied.

  12. Docking and Antiherpetic Activity of 2-Aminobenzo[de]-isoquinoline-1,3-diones

    Directory of Open Access Journals (Sweden)

    Rashad Al-Salahi

    2015-03-01

    Full Text Available As part of our search for new compounds having antiviral effects, the prepared 2-aminonaphthalimide series was examined for its activity against the herpes simplex viruses HSV-1 and HSV-2. This represents the first study of the antiviral effects of this class of compounds. The new series of 2-amino-1H-benzo[de]isoquinoline-1,3-diones was examined against HSV-1 and HSV-2 using a cytopathic effect inhibition assay. In terms of effective concentration (EC50, furaldehyde, thiophene aldehyde and allyl isothiocyanide derivatives 14‒16 showed potent activity against HSV-1 (EC50 = 19.6, 16.2 and 17.8 μg/mL, compared to acyclovir as a reference drug (EC50 = 1.8 μg/mL. Moreover, 14 and 15 were found to exhibit valuable activity against HSV-2. Many of the tested compounds demonstrated weak to moderate EC50 values relative to their inactive parent compound (2-amino-1H-benzo[de]isoquinoline-1,3-dione, while compounds 7, 9, 13, 14, 15, 16, 21 and 22 were the most active set of antiviral compounds throughout this study. The cytotoxicity (CC50, EC50, and the selectivity index (SI values were determined. In a molecular docking study, the ligand-receptor interactions of compounds 1–24 and their parent with the HSV-1 thymidine kinase active site were investigated using the Molegro Virtual Docker (MVD software. Based on the potent anti-HSV properties of the previous naphthalimide condensate products, further exploration of this series of 2-amino-1H-benzo[de]isoquinoline-1,3-diones is warranted.

  13. Detection of chitinase activity by 2-aminobenzoic acid labeling of chito-oligosaccharides

    NARCIS (Netherlands)

    Ghauharali-van der Vlugt, Karen; Bussink, Anton P.; Groener, Johanna E. M.; Boot, Rolf G.; Aerts, Johannes M. F. G.

    2009-01-01

    Chitinases are hydrolases capable of hydrolyzing the abundant natural polysaccharide chitin. Next to artificial fluorescent substrates, more physiological chito-oligomers are commonly used in chitinase assays. Analysis of chito-oligosaccharides products is generally accomplished by UV detection.

  14. X-ray structural investigation into complexes of p-aminobenzoic acid and metals

    International Nuclear Information System (INIS)

    Amiraslanov, I.R.; Musaev, F.N.; Mamedov, Kh.S.

    1982-01-01

    X-ray structural investigation of p-aminobenzoatodiaqua-strontium Sr(H 2 NC 6 H 4 COO) 2 x2H 2 o' was carried out. Crystals were rhombic: a=6.86(1), b=13.39(2), c=18.58(2) A, V=1705 A, Z=4, space group P2 1 2 1 2 1 . The basis of the structure was formed by infinite along the axis a chains of strontium atom octavertices articulated with common oxygen vertices. Sr-O bond lengths were 2.46-2.74 A; the distance between strontium neighbour - ring atom 4.07(1) A. Bond angles were presented

  15. Crystal structure of 4-aminobenzoic acid–4-methylpyridine (1/1

    Directory of Open Access Journals (Sweden)

    M. Krishna Kumar

    2015-02-01

    Full Text Available In the title 1:1 adduct, C6H7N·C7H7NO2, the carboxylic acid group is twisted at an angle of 4.32 (18° with respect to the attached benzene ring. In the crystal, the carboxylic acid group is linked to the pyridine ring by an O—H...N hydrogen bond, forming a dimer. The dimers are linked by N—H...O hydrogen bonds, generating (010 sheets.

  16. Thermal behaviour and antimicrobial assay of some new zinc(II) 2-aminobenzoate complex compounds with bioactive ligands

    Czech Academy of Sciences Publication Activity Database

    Krajníková, A.; Rotaru, A.; Györyová, K.; Homzová, K.; Manolea, H. O.; Kovářová, Jana; Hudecová, D.

    2015-01-01

    Roč. 120, č. 1 (2015), s. 73-83 ISSN 1388-6150 Institutional support: RVO:61389013 Keywords : antimicrobial * nicotinamide derivatives * non-isothermal kinetics Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.781, year: 2015

  17. Hemi(4,4′-bipyridinium hexafluoridophosphate bis(4-aminobenzoic acid 4,4′-bipyridine monohydrate

    Directory of Open Access Journals (Sweden)

    Yi-Fan Luo

    2009-02-01

    Full Text Available In the title compound, 0.5C10H10N22+·PF6−·C10H8N2·2C7H7NO2·H2O, the cation is located on a center of symmetry. The crystal structure is determined by a complex three-dimensional network of intermolecular O—H...O, O—H...N, N—H...N and N—H...F hydrogen bonds. π–π stacking interactions between neighboring pyridyl rings are also present; the centroid–centroid distance is 3.643 (5 Å. The hexafluoridophosphate anion is disordered over two positions with site-occupancy factors of ca 0.6 and 0.4.

  18. The crystal structure of the complex formed by 4-nitropyridine n-oxide with 3-aminobenzoic acid

    Directory of Open Access Journals (Sweden)

    R. Moreno Fúquene

    2010-06-01

    Full Text Available La estructura cristalina y molecular del complejo formado por enlace de hidrógeno entre la 4-nitropiridina N-oxido y el ácido 3-aminobenzóico fue estudiado por difracción de rayos X. Los cristales fueron obtenidos a partir de una solución equimolecular en acetonitrilo, son monoclínicos P2/c, con a=7,325(3, b=10,173(l, c=16,701(7Á, fl=101,74(3-, V=1219( 1Á^ e Dc= 1,511 g cm^ para Z=4. La estructura fue resuelta por métodos directos y afinada por mínimos cuadrados con 1^20(1, obteniéndose un coeficiente de discordancia R=0.0504 y R^= 0.0485. Las moléculas que forman el complejo presentan un enlace de hidrógeno fuerte entre el grupo carboxilo y el grupo N-óxido con una distancia o—o igual a 2.539(7A. El ángulo dihedro formado por los planos medios de sus anillos es igual a 44.5(2°. Las moléculas de 4-nitropiridina N-óxido y del ácido 3-aininobenzóico presentan superposición en la dirección [100], con una distancia media de 3.25(4 y 3.42(4Á. Es discutido también el efecto de la substitución meta en el ácido 3-aminobenzóico sobre el empaquetamiento molecular

  19. A redetermination from the original data of the crystal structure of 2-amino-4,6-dimethoxy-pyrimidin-1-ium 4-aminobenzoate

    Czech Academy of Sciences Publication Activity Database

    Fábry, Jan

    2016-01-01

    Roč. 72, Apr (2016), 512-515 ISSN 2056-9890 R&D Projects: GA MŠk LO1603 Institutional support: RVO:68378271 Keywords : crystal structure redetermination * H-bonding * symmetric H-bonds * refinement constraints * restraints Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. Para-aminobenzoic acid used as a marker for completeness of 24 hour urine: Assessment of control limits for a specific HPLC method

    DEFF Research Database (Denmark)

    Jakobsen, Jette; Ovesen, L.; Fagt, Sisse

    1997-01-01

    (20-59 y; n = 34) PABA was taken as recommended, whereas in the older age group (60-80 y; n = 22) the last PABA dosage was advanced three hours. Results: Protocol 1: HPLC gave significantly lower PABA recovery results compared to colorimetry, the difference between methods being 23.9 +/- 5.5 mg/24 h...... in a complete 24 h urine differs from the limit based on colorimetry. This study found a limit of 187 mg/24 h corresponding to the lower 95% confidence limit for a single subject....

  1. Enhancing pterin and para-aminobenzoate content is not sufficient to successfully biofortify potato tubers and Arabidopsis thaliana plants with folate

    NARCIS (Netherlands)

    Blancquaert, D.; Storozhenko, S.; Daele, W.; Stove, C.; Visser, R.G.F.; Lambert, W.; Straeten, van der D.

    2013-01-01

    Folates are important cofactors in one-carbon metabolism in all living organisms. Since only plants and micro- organisms are capable of biosynthesizing folates, humans depend entirely on their diet as a folate source. Given the low folate content of several staple crop products, folate deficiency

  2. 2-[(1-Benzamido-2-methoxy-2-oxoethylamino]benzoic Acid

    Directory of Open Access Journals (Sweden)

    Alami Anouar

    2013-01-01

    Full Text Available The carboxylic α,α-diaminoester 2-[(1-benzamido-2-methoxy-2-oxoethyl amino]benzoic acid is obtained by N-alkylation of methyl α-azido glycinate N-benzoylated with 2-aminobenzoic acid.

  3. Trivalent rare earth complexes of some potential antiinflammatory and antipyretic compounds

    International Nuclear Information System (INIS)

    Basak, Devashish

    1994-01-01

    Binary complexes of 2-aminobenzoic acid (2-ABA), 3-aminobenzoic acid (3-ABA) and 4-aminobenzoic acid (4-ABA) with La(III), Pr(III), Nd(III), Sm(III) and Gd(III) have been studied paper electrophoretically at different temperatures and a constant ionic strength. The stability constants of the complexes have been reported. (author). 6 refs., 1 tab

  4. Determination of the conformation of 2-hydroxy- and 2-aminobenzoic acid dimers using 13C NMR and density functional theory/natural bond order analysis: the central importance of the carboxylic acid carbon.

    Science.gov (United States)

    Burnette, Ronald R; Weinhold, Frank

    2006-07-20

    The 13C chemical shift for the carboxylic acid carbon provides a powerful diagnostic probe to determine the preferred isomeric dimer structures of benzoic acid derivatives undergoing intra- and intermolecular H-bonding in the gas, solution and crystalline phases. We have employed hybrid density functional calculations and natural bond orbital analysis to elucidate the electronic origins of the observed 13C shieldings and their relationship to isomeric stability. We find that delocalizing interactions from the carbonyl oxygen lone pairs (nO) into vicinal carbon-oxygen and carbon-carbon antibonds (sigmaCO*,sigmaCC*) make critical contributions to the 13C shieldings, and these nO --> sigmaCO*, nO --> sigmaCC* interactions are in turn sensitive to the intramolecular interactions that dictate dimer structure and stability. The carboxyl carbon atom can thus serve as a useful detector of subtle structural and conformational features in this pharmacologically important class of carboxylic acid interactions.

  5. hydrothermal synthesis and characterisation of amine-templated

    African Journals Online (AJOL)

    PROF EKWUEME

    showed that the complexes were insoluble in water, ethanol, DMF and DMSO. KEYWORDS: Hydrothermal synthesis, metal phosphates, p-aminobenzoic acid, ethylacetoacetate, ethylammonium-. 4-aminobenzoate. INTRODUCTION. One of the major areas of materials science is the development of solid state materials with ...

  6. Protonation site for anilines in aqueous media

    Directory of Open Access Journals (Sweden)

    INNA M. UCHAEVA

    2002-02-01

    Full Text Available By means of the PM3 method it has been shown that the protonation of 2-, 3-, 4-methoxyanilines, 4-methylthioaniline, 2-, 3-, 4-aminobenzoic acids, 2-, 3-, 4-nitroanilines in the gaseous phase proceeds via the amine nitrogen atom. The same result, attributed to the aqueous medium, was obtained for 4-methoxyaniline, 4-aminobenzoic acid and 4-nitroaniline.

  7. Living Polycondensation: Synthesis of Well-Defined Aromatic Polyamide-Based Polymeric Materials

    KAUST Repository

    Alyami, Mram Z.

    2016-11-01

    Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low polydispersity and controlled molecular weights, and on the other hand, on studying their thermal properties. In the first project, well-defined poly (N-octyl-p-aminobenzoate) and poly (N-butyl-p-aminobenzoate) were synthesized, and for the first time, their thermal properties were studied. In the second project, ethyl4-aminobenzoate, ethyl 4-octyl aminobenzoate and 4-(hydroxymethyl) benzoic acid were used as novel efficient initiators of ε-caprolactone with t-BuP2 as a catalyst. Macroinitiator and Macromonomer of poly (ε-caprolactone) were synthesized with ethyl 4-octyl aminobenzoate and ethyl 4-aminobenzoate as initiators to afford polyamide-block-poly (ε-caprolactone) and polyamide-graft-poly (ε-caprolactone) by chain growth condensation polymerization (CGCP). In the third project, a new study has been done on chain growth condensation polymerization to discover the probability to synthesize new polymers and studied their thermal properties. For this purpose, poly (N-cyclohexyl-p-aminobenzoate) and poly (N-hexyl-p-aminobenzoate) were synthesized with low polydispersity and controlled molecular weights.

  8. A detailed in vitro study of naproxen metal complexes in quest of ...

    African Journals Online (AJOL)

    Md. Sharif Hasan

    2016-07-01

    Jul 1, 2016 ... possibilities of using Naproxen metal complexes for different therapeutic ..... FTIR spectra, scanning electron microscopy and HPLC study of Naproxen metal ..... aminobenzoic acid and 2-aminophenol and their coordination.

  9. EFFECTS OF ANESTHESIA (MS222) ON LIVER BIOTRANSFORMATION IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

    Science.gov (United States)

    Tricaine methanesulfonate (3-aminobenzoic acid ethyl ester methanesulfonate; MS222) is a widely used fish anaesthetic. While there have been several studies addressing the impact of its use on subsequently measured biotransformation rates, the measured influence on normal functio...

  10. EFFECTS OF ANESTHESIA (TRICAINE METHANESULFONATE, MS-222) BIOTRANSFORMATION IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

    Science.gov (United States)

    Tricaine methanesulfonate (3-aminobenzoic acid eithyl ester methanesulfonate, tricaine, MS-222, Finquel), an anesthetic for fish, has been used extensively in aquatic toxicology to allow surgical procedures for in vivo studies and to permit in vitro preparations of isolated perfu...

  11. Acid hydrolysis of kallar grass (leptochloa fusca) for the production

    International Nuclear Information System (INIS)

    Chughtai, F.A.; Shah, M.H.

    1993-01-01

    Acid hydrolysis of kallar grass (leptochloa fusca) was carried of with various concentrations of sulphuric acid, ortho phosphoric acid and hydrochloric acid to produce furfural. The study revealed that activity of various hydrolysing acids to produce furfural from kallar grass was of the following order H/sub 2/SO/sub 4/ > H/sub 3/PO/sub 4/ > HCl. Optimum yield (4.78%) of the produce was obtained when the material was digested with 19% H/sub 2/SO/sub 4/ for a period of 20 minutes. (author)

  12. Comparison of the reactivity of the materials having two different kinds of functional groups by applying hydrogen-isotope exchange reaction

    International Nuclear Information System (INIS)

    Imaizumi, H.; Yumoto, Y.

    1995-01-01

    The hydrogen-isotope exchange reaction between m- (or p-) aminobenzoic acid and HTO vapor has been observed in order to estimate the scale of the reactivity of the material. Each rate constant has been obtained by the A''-McKay plot method. Comparing the rate constants, the following three items have been confirmed: (1) the reactivity of both COOH and NH 2 groups increases with temperature; (2) the degree of the effect of the COOH (or NH 2 ) group on the reactivity in m-aminobenzoic acid is larger than that in p-aminobenzoic acid; (3) the A''-McKay plot method is useful in studying the reactivity of the materials not only with one (or the same kinds of) functional group(s), but also with two different kinds of functional groups. (orig.)

  13. Novel cleavage of reductively aminated glycan-tags by N-bromosuccinimide to regenerate free, reducing glycans.

    Science.gov (United States)

    Song, Xuezheng; Johns, Brian A; Ju, Hong; Lasanajak, Yi; Zhao, Chunmei; Smith, David F; Cummings, Richard D

    2013-11-15

    Glycans that are fluorescently tagged by reductive amination have been useful for functional glycomic studies. However, the existing tags can introduce unwanted properties to the glycans and complicate structural and functional studies. Here, we describe a facile method using N-bromosuccinimide (NBS) to remove the tags and efficiently regenerate free reducing glycans. The regenerated free reducing glycans can be easily analyzed by routine mass spectrometry or retagged with different tags for further studies. This new method can be used to efficiently remove a variety of fluorescent tags installed by reductive amination, including 2-aminobenzoic acid and 2-aminopyridine. NBS treatment essentially transforms the commonly used 2-aminobenzoic linkage to a cleavable linkage. It can be used to cleave printed glycans from microarrays and cleave neoglycopeptides containing a 2-aminobenzoic linker.

  14. Methemoglobin-forming effect and its role in the mechanism of action of some radioprotectors of benzo-2,1,3-thiadiazole class

    International Nuclear Information System (INIS)

    Vladimirov, V.G.; Chigareva, N.G.; Belen'kaya, I.A.; Strel'nikov, Yu.E.

    1977-01-01

    The ability of some benzo-2,1,3-tiadiazole derivatives to form methemoglobin in blood has been investigated. It has been shown that 30 min after intraperitoneal administration to mice of radioprotective doses of the preparations, the methemoglobin level in blood does not exceed 5%. After administration of a toxic dose of 4-aminobenzo-2,1,3-tiadiazole, the amount of methemoglobin in the mouse blood makes 14%. After per os administration of 4-aminobenzo-2,1,3-tiadiazole to dogs methemoglobin content of blood makes almost 50% which can provide a radioprotective action of this compound. Using substances preventing oxidation of hemoglobin to methemoglobin (isonicotinic acid hydrazide and 2-methoxy-9-phenazin sulphate) it has been shown that methemoglobin, formed in the mouse blood, does not play a leading part in manifestation of radioprotective and toxic properties of 4-aminobenzo-2,1,3-tiadiazole

  15. Improvement of organic compounds labelling method with the use of thermally activated tritium gas

    International Nuclear Information System (INIS)

    Nejman, L.A.; Smolyakov, V.S.; Antropova, L.P.

    1982-01-01

    Use of a support (various types of papers) is recommended for organic compounds labelling by tritium gas activated at a hot tungsten filament. This improvement increases chemical and radiochemical yields and makes the experiment simpler and faster. Generally labelled triethyloxonium tetra-fluoroborate, ethyl-p-aminobenzoate, p-aminobenzoic acid (Na-salt), A-factor (a natural regulator of streptomycin biosynthesis), decapeptide angiotensin I, phospholipid 1, 2 - dimyristoyl-sn-glycero-3--phosphocholine and E. coli tRNAs have been prepared by this method. Molar radioactivity of the labelled compounds is in the range of 1-200 GBg/mmole [ru

  16. The reaction of astatine with aromatic diazonium compounds

    International Nuclear Information System (INIS)

    Visser, G.W.M.; Diemer, E.L.

    1982-01-01

    Astatine reacts prefrentially with that type of aromatic diazonium salt that decomposes via a radical reaction channel (homolytic breakage of the C-N bond). The dediazonation with p-aminobenzoic acid and p-toluidine as model compounds was investigated through estatin produced in the 209 Bi(α,2n) 211 At reaction. (author)

  17. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Calcium carbonate polymorphs were precipitated at room temperature and 80°C by varying the precipitation pH, carbonate source, effect of solvent in presence and absence of structure directing agent such as para-aminobenzoic acid. Calcite phase of calcium carbonate was obtained when sodium hydrogen carbonate ...

  18. The effects of cyclodextrins on drug release from fatty suppository bases : III. Application of cyclodextrin derivatives

    NARCIS (Netherlands)

    Frijlink, H.W.; Paiotti, S.; Eissens, Anko; Lerk, C.F.

    1992-01-01

    The complexation of both n-butyl-4-aminobenzoate and diazepam with dimethyl-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin, respectively, was studied. Solid complexes were prepared by freeze-drying. The complexes were incorporated in fatty suppositories and drug release was studied, both in

  19. Isolation, structure, and synthesis of viridic acid, a new tetrapeptide mycotoxin of Penicillium viridicatum Westling

    International Nuclear Information System (INIS)

    Holzapfel, C.W.; Koekemoer, J.M.; Van Dyk, M.S.

    1986-01-01

    The isolation of a new toxic metabolite, viridic acid, from Penicillium viridicatum Westling is described. The chemical and spectroscopic properties of the compound are interpreted in terms of the tetrapeptide structure (N,N-dimethyl-o-aminobenzoyl)-glycyl-(N'-methyl-L-valyl)-o-aminobenzoic acid. The structure and chirality of viridic acid were confirmed by total synthesis

  20. Coexistent vitiligo and actinic lichen planus

    Directory of Open Access Journals (Sweden)

    Ahmad Khalil

    1992-01-01

    Full Text Available A case of vitiligo who subsequently developed the lesions of lichen planus is described. Both types of lesions occurred on sun exposed areas, aggravated on photochemotherapy and showed improvement on para aminobenzoic acid cream application with avoidance of sun exposure. The possibility of common aetiological background is discussed.

  1. Comparative analysis of monoclonal antibody N-glycosylation using stable isotope labelling and UPLC-fluorescence-MS.

    Science.gov (United States)

    Millán Martín, Silvia; Delporte, Cédric; Farrell, Amy; Navas Iglesias, Natalia; McLoughlin, Niaobh; Bones, Jonathan

    2015-03-07

    A twoplex method using (12)C6 and (13)C6 stable isotope analogues (Δmass = 6 Da) of 2-aminobenzoic acid (2-AA) is described for quantitative analysis of N-glycans present on monoclonal antibodies and other glycoproteins using ultra performance liquid chromatography with sequential fluorescence and accurate mass tandem quadrupole time of flight (QToF) mass spectrometric detection.

  2. Oxo-halogen complexes of molybdenum (V) with bioactive polyfunctional organic ligands

    International Nuclear Information System (INIS)

    Azizkulova, O.A.

    1997-01-01

    The present work dedicated to systematization of synthesized by author coordinated compounds of molybdenum with aminoacetic, asparaginic, glutamic, n-aminobenzoic acids, 1-methyl-2-imidazole, thio-semi-carbazone, thia-dia-zole and its derivatives each of which has from 2 till 5 potentially donor atom

  3. Discovery of novel inhibitors for DHODH via virtual screening and X-ray crystallographic structures

    Energy Technology Data Exchange (ETDEWEB)

    McLean, Larry R.; Zhang, Ying; Degnen, William; Peppard, Jane; Cabel, Dasha; Zou, Chao; Tsay, Joseph T.; Subramaniam, Arun; Vaz, Roy J.; Li, Yi (Sanofi)

    2010-10-28

    Amino-benzoic acid derivatives 1-4 were found to be inhibitors for DHODH by virtual screening, biochemical, and X-ray crystallographic studies. X-ray structures showed that 1 and 2 bind to DHODH as predicted by virtual screening, but 3 and 4 were found to be structurally different from the corresponding compounds initially identified by virtual screening.

  4. Mutasynthesis of fluorinated pactamycin analogues and their antimalarial activity.

    Science.gov (United States)

    Almabruk, Khaled H; Lu, Wanli; Li, Yuexin; Abugreen, Mostafa; Kelly, Jane X; Mahmud, Taifo

    2013-04-05

    A mutasynthetic strategy has been used to generate fluorinated TM-025 and TM-026, two biosynthetically engineered pactamycin analogues produced by Streptomyces pactum ATCC 27456. The fluorinated compounds maintain excellent activity and selectivity toward chloroquine-sensitive and multidrug-resistant strains of malarial parasites as the parent compounds. The results also provide insights into the biosynthesis of 3-aminobenzoic acid in S. pactum.

  5. A new smart additive of reinforced concrete based on modified hydrotalcites: Preparation, characterization and anticorrosion applications

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.; Polder, R.

    2012-01-01

    A carbonate form of Mg-Al-hydrotalcite and its p-aminobenzoate (pAB) modified derivative (i.e.,Mg(2)Al-pAB) were synthesized and characterized by means of XRD and FT-IR. The anticorrosion behavior was evaluated based on open circuit potential (OCP) of carbon steel in simulated concrete pore solution

  6. Photoactivatable Mussel-Based Underwater Adhesive Proteins by an Expanded Genetic Code.

    Science.gov (United States)

    Hauf, Matthias; Richter, Florian; Schneider, Tobias; Faidt, Thomas; Martins, Berta M; Baumann, Tobias; Durkin, Patrick; Dobbek, Holger; Jacobs, Karin; Möglich, Andreas; Budisa, Nediljko

    2017-09-19

    Marine mussels exhibit potent underwater adhesion abilities under hostile conditions by employing 3,4-dihydroxyphenylalanine (DOPA)-rich mussel adhesive proteins (MAPs). However, their recombinant production is a major biotechnological challenge. Herein, a novel strategy based on genetic code expansion has been developed by engineering efficient aminoacyl-transfer RNA synthetases (aaRSs) for the photocaged noncanonical amino acid ortho-nitrobenzyl DOPA (ONB-DOPA). The engineered ONB-DOPARS enables in vivo production of MAP type 5 site-specifically equipped with multiple instances of ONB-DOPA to yield photocaged, spatiotemporally controlled underwater adhesives. Upon exposure to UV light, these proteins feature elevated wet adhesion properties. This concept offers new perspectives for the production of recombinant bioadhesives. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Study of the growth and pyroelectric properties of TGS crystals doped with aniline-family dipolar molecules

    Science.gov (United States)

    Zhang, Kecong; Song, Jiancheng; Wang, Min; Fang, Changshui; Lu, Mengkai

    1987-04-01

    TGS crystals doped with aniline-family dipolar molecules (aniline, 2-aminobenzoic acid, 3-aminobenzoic acid, 3-aminobenzene-sulphonic acid, 4-aminobenzenesulphonic acid and 4-nitroraniline) have been grown by the slow-cooling solution method. The influence of these dopants on the growth habits, crystal morphology pyroelectric properties, and structure parameters of TGS crystals has been systematically investigated. The effects of the domain structure of the seed crystal on the pyroelectric properties of the doped crystals have been studied. It is found that the spontaneous polarization (P), pyroelectric coefficient (lambda), and internal bias field of the doped crystals are slightly higher than those of the pure TGS, and the larger the dipole moment of the dopant molecule, the higher the P and lambda of the doped TGS crystal.

  8. Crystal and molecular structure of eight organic acid-base adducts from 2-methylquinoline and different acids

    Science.gov (United States)

    Zhang, Jing; Jin, Shouwen; Tao, Lin; Liu, Bin; Wang, Daqi

    2014-08-01

    Eight supramolecular complexes with 2-methylquinoline and acidic components as 4-aminobenzoic acid, 2-aminobenzoic acid, salicylic acid, 5-chlorosalicylic acid, 3,5-dinitrosalicylic acid, malic acid, sebacic acid, and 1,5-naphthalenedisulfonic acid were synthesized and characterized by X-ray crystallography, IR, mp, and elemental analysis. All of the complexes are organic salts except compound 2. All supramolecular architectures of 1-8 involve extensive classical hydrogen bonds as well as other noncovalent interactions. The results presented herein indicate that the strength and directionality of the classical hydrogen bonds (ionic or neutral) between acidic components and 2-methylquinoline are sufficient to bring about the formation of binary organic acid-base adducts. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, the complexes 1-8 displayed 2D-3D framework structure.

  9. Intercalation of anionic organic ultraviolet ray absorbers into layered zinc hydroxide nitrate.

    Science.gov (United States)

    Cursino, Ana Cristina Trindade; Gardolinski, José Eduardo Ferreira da Costa; Wypych, Fernando

    2010-07-01

    Layered zinc hydroxide nitrate (ZHN) was synthesized and nitrate ions were topotactically exchanged with three different anionic species of commercial organic ultraviolet (UV) ray absorbers: 2-mercaptobenzoic acid, 2-aminobenzoic acid, and 4-aminobenzoic acid. The exchange reactions were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) spectroscopy, and thermal analysis (thermogravimetry, TGA, and differential thermal analysis, DTA). In all the anionic exchanged products, evidence of grafting of the organic species onto the inorganic matrix was obtained. In general, after intercalation/grafting, the UV absorption ability was improved in relation to the use of the parent organic material, showing that layered hydroxide salts (LHS) can be good alternative matrixes for the immobilization of organic species with UV-blocking properties in cosmetic products. Copyright 2010 Elsevier Inc. All rights reserved.

  10. An Efficient Solid-phase Parallel Synthesis of 2-Amino and 2-Amidobenzo[d]oxazole Derivatives via Cyclization Reactions of 2-Hydroxyphenylthiourea Resin

    International Nuclear Information System (INIS)

    Jung, Selin; Kim, Seulgi; Lee, Geehyung; Gong, Youngdae

    2012-01-01

    An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxyphenylthiourea resin 3. The resin-bound 2-hydroxy-phenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane (CH 2 Cl 2 )

  11. Synthesis, biological activity and computational studies of novel azo-compounds

    International Nuclear Information System (INIS)

    Ashraf, J.; Murtaza, S.; Mughal, E.U.; Sadiq, A.

    2017-01-01

    In the present protocol, we report the synthesis and characterization of some novel azo-compounds starting from 4-methoxyaniline and 4-aminophenazone, which were diazotized at low temperature. 4-nitrophenol, 2-aminobenzoic acid, benzamide, 4-aminobenzoic acid, resorcinol, o-bromonitrobenzene and 2-nitroaniline were used as active aromatic coupling compounds for the second step. The synthesized compounds were investigated for their potential antibacterial activities by using disc diffusion method against Escherichia coli, Shigellasonnei, Streptococcus pyrogenes, Staphylococcus aureus and Neisseria gonorrhoeae strains. They were also subjected to antioxidant activities by using DPPH method. Results revealed that the compounds of 4-methoxyaniline and 4-aminophenazone showed good antibacterial activity against all strains, where as some azo-compounds have moderate to good antioxidant activities. Furthermore, these compounds were studied by computational analysis. (author)

  12. Synthesis and studies of some magnesium complexes of aromatic hydrazones

    International Nuclear Information System (INIS)

    Adeniyi, A.A.; Oyedeji, O.O.; Aremu, J.A.; Okedeyi, J.O.; Bourne, S.A.

    2006-01-01

    Six esters were synthesized from their parent acids, while their corresponding hydrazides were subsequently synthesized from these asters. The hydrazides, on reaction with benzaldehyde, produced their respective hydrazones, namely, benzoic hydrazone (BH), m-nitrobenzoic hydrazone (m-NBH), p-nitrobenzoic hydrazone (p-NBH), 3,5 dinitrobenzoic hydrazone (3,5-dnbh), m-aminobenzoic hydrazone (m-ABH), and p-aminobenzoic hydrazone (p-ABH). These hydrazones, on interaction with magnesium chloride yielded their corresponding magnesium complexes. These complexes were off-white, grey or brownish in colour. These complexes were characterized on the basis of spectral data and metal analysis. Metal to ligand stoichiometry of 1: 3/2 and 1: 5/2 has been proposed for the complexes. The relevant infrared bands in the ligands and complexes were used to assign the probable point(s) of coordination. (author)

  13. Modified hydrotalcites for improved corrosion protection of reinforcing steel in concrete – preparation, characterization, and assessment in alkaline chloride solution

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.; Cerezo, J.; Mol, J.M.C.; Polder, R.

    2016-01-01

    Six MgAl hydrotalcites (Mg/Al = 2 and 3) were synthesized through the modification of two carbonate hydrotalcites (i.e., Mg(2)AlCO3 and Mg(3)AlCO3) by two amino acids (11aminoundecanoic acid and paminobenzoic acid) and sodium nitrite. They were characterized by means of XRD, FTIR, TG/DSC, and

  14. 3-[(E-(2,4-Dichloropbenzylideneamino]benzoic acid

    Directory of Open Access Journals (Sweden)

    Adnan Ashraf

    2011-01-01

    Full Text Available In the crystal of the title compound, C14H9Cl2NO2, inversion-related dimers with R22(8 ring motifs are formed by intermolecular O—H...O hydrogen bonding. The 3-aminobenzoic acid group and the 2,4-dichlobenzaldehyde moiety subtend a dihedral angle of 55.10 (2°. The H atom of the carboxyl group is disordered over two sites with equal occupancies.

  15. The study of 2-acetylaminotoluene ozonolysis in acetic ACID

    OpenAIRE

    Галстян, Андрій Генрійович

    2014-01-01

    The kinetics and mechanism of ozone reaction with 2-aminotoluene and its acylated derivative in acetic acid were studied in order to determine the possibility of obtaining 2-aminobenzoic acid.It is shown that the 2-aminotoluene ozonolysis reaction in acetic acid solution runs at high speed, and preferably on the free electron pair of the amino group to form mainly resinous compounds; oxidation products by the methyl group of the substrate are not formed under these conditions. The ozone attac...

  16. Comparison of ionisation properties of aetma-labeled saccharides with common labels

    OpenAIRE

    Partyka, J. (Jan); Foret, F. (František)

    2015-01-01

    We have tested (2-aminoethyl)trimethylammonium (AETMA) as a label for analysis of oligosaccharides by capillary electrophoresis with electrospray (ESI) mass spectrometry detection and compared its performance to taurine, 2-aminobenzoic acid, 2-aminobenzamide and 8-aminopyrene-1,3,6-trisulfonic acid. The AETMA-labeled saccharides were provided higher ionization signals in positive mode than native sodium or ammonium adducts and equal or higher signals than saccharides labeled by the more commo...

  17. Photooxidative cleavage of 4(1H)-quinolinones to 2-acylaminobenzoic acids and derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Staskun, B. (University of the Witwatersrand, Johannesburg (South Africa). Dept. of Chemistry); Foote, C.S. (California Univ., Los Angeles (USA). Dept. of Chemistry)

    1984-12-01

    4(1H)-Quinolinones undergo oxidative cleavage to afford the corresponding 2-acylaminobenzoic acids when subjected to dye-sensitized photooxygenation in methanol-aqueous sodium hydroxide solution. The derived 2-aminobenzoic acid was the predominant product in certain instances. The reaction, with singlet oxygen suggested as the active species, provides an alternative methodology for access to nuclear- substituted anthranilic acids and derivatives.

  18. Effect of the method for rhenium neptasulfide preparation on its catalytic properties in hydrogenation of nitrobenzene and m-nitrobenzoic acid

    International Nuclear Information System (INIS)

    Pal'chevskaya, T.A.; Bogutskaya, L.V.; Belousov, V.M.

    1988-01-01

    The effect of conditions of rhenium heptasulfide synthesis by thiosulfate method on its physicochemical and catalytic properties during hydrogenation of nitrobenzene and m-nitrobenzoic acid has been studied. It is shown that the maximum yield of m-aminobenzoic acid can be attained on insoluble sulfide rhenium contacts, containing excessive amount of sulfur (3.5 %). Under certain conditions of catalyst synthesis particles of Re 2 S 7 soluble in dimethylformamide are formed, which possess selectivity towards amine

  19. Carotamine, a Unique Aromatic Amide from Daucus Carota L. Var Biossieri (Apiaceae

    Directory of Open Access Journals (Sweden)

    Mohamed M. El-Azizi

    2002-06-01

    Full Text Available The unique aromatic peptide 4-(p-aminobenzoylamino-2-aminobenzoic acid, carotamine, together with 2,4-diaminobenzoic acid, isolated for the first time from a plant source, were identified from the aqueous alcoholic extract of the aerial parts of Daucus carota L. var. boissieri (Apiaceae. The structures were determined through conventional methods of analysis and confirmed by LC-ESI/MS and NMR spectral analysis.

  20. SYNTHESIS, SPECTROSCOPIC CHARACTERIZATION AND ...

    African Journals Online (AJOL)

    userpc

    ABSTRACT. A tridendatate Schiff base,L, 2-((2-hydroxynaphthalen-1-yl) methyleneamino)benzoic acid was prepared by condensation of 2-aminobenzoic acid with 2-hydroxy-1-naphthaldehyde.The prepared ligand was used to synthesize Sm(III) and Dy(III) complexes [LnL(NO3)2]NO3.2H2O,. (Ln=Sm(III) and Dy(III)).

  1. Emanation-thermal characteristics of Ba-salts of some aromatic acids in the temperature range between 298 and 373 K

    Energy Technology Data Exchange (ETDEWEB)

    Balek, V; Prachar, M [Ustav Jaderneho Vyzkumu, Rez (Czechoslovakia); Kroupa, J [Vyzkumny Ustav Syntetickych Pryskyric a Laku, Pardubice (Czechoslovakia)

    1977-01-01

    The paper presents the emanation-thermal characteristics of Ba salts of some monocarboxylic acids (phtalic, isophtalic and terephtalic) and dicarboxylic acids (benzoic, salicylic, 1,4-aminobenzoic, 1,2-Cl-benzoic and 1,2-I-benzoic). It is shown that the emanation thermal characteristics measured in the temperature range between 298 and 373 K are suitable for estimating diffusion properties of studied organic solids. An apparatus for determining emanation-thermal characteristics is proposed.

  2. Study of the protective properties of paraaminobenzoic acid for cornea of adult rats under X-radiation

    International Nuclear Information System (INIS)

    Stroeva, O.G.; Panova, I.G.; Mel'nikova, I.I.

    1997-01-01

    To test the efficiency of para-aminobenzoic acid (PABA) as a radioprotector for mammal tissues the protective properties of PABA for cornea of adult rats-males exposed to single whole-body irradiation were studied. X-irradiation was performed using RUM-17 facility at the dose of 5 Gy (dose rate is of 0.886 Gy/min). Results obtained prove reliably radioprotective and therapeutic effect of PABA on the cornea cells [ru

  3. Synthesis of schiff bases of pyridine-4-carbaldehyde and their antioxidant and DNA binding studies

    International Nuclear Information System (INIS)

    Shamim, S.; Murtaza, S.; Nazar, M.F.

    2016-01-01

    A series of Schiff bases of pyridine-4-carbaldehyde with 3-aminobenzoic acid, 2-aminobenzoic acid, 4-aminobenzoic acid, 1,3-phenylenediamine, 1,2-phenylenediamine, 2-aminothiophenol, 4-aminoantipyrene, 2-aminophenol and naphthalene-1-amine was synthesized and compounds were characterized by FTIR, NMR and mass spectrometry. The synthesized compounds were evaluated for their antioxidant and DNA binding interaction studies. DPPH scavenging method was used to evaluate the antioxidant activities of synthesized Schiff bases at six gradually increasing concentrations of 0.5-5mg/ml. 2-((pyridin-4-ylmethylidene)amino)phenol came out to be the most efficient antioxidant at a concentration of 4mg/ml with 74% inhibition of free radicals generated by DPPH. The DNA binding interaction of the synthesized Schiff bases was determined using UV-Vis absorption titration method. Both the hypochromic and hyperchromic effects were observed along the series. The values for the binding constant (K) and free energy change (G) were calculated and most of the Schiff bases have high positive K values which indicate the efficient binding of Schiff bases with DNA. Molecular docking studies as carried out using PatchDock molecular algorithm software also indicated the high values for geometrical shape complementarity score suggesting the stabilities of Schiff bases/DNA complex. Docking studies also suggested the minor groove binding of the Schiff bases with DNA. Drug-likeness of the synthesized compounds was also tested in silico and the results are accordingly discussed. (author)

  4. Green Approach—Multicomponent Production of Boron—Containing Hantzsch and Biginelli Esters

    Directory of Open Access Journals (Sweden)

    René Miranda

    2013-01-01

    Full Text Available Multicomponent reactions are excellent methods that meet the requirements of green chemistry, by reducing the number of steps, and consequently reducing purification requirements. Accordingly, in this work, 11 novel hybrid-boron-containing molecules, namely eight 1,4-dihydropyridines and three 3,4-dihydropyrimidinones, derived from formylphenylboronic acids (ortho, meta and para, were obtained using a green approach, involving H-4CR and B-3CR practices, in the presence of ethanol, which is a green solvent, and using three comparatively different modes of activation (mantle heating, yield 3%–7% in 24 h, Infrared Radiation (IR irradiation, yield 12%–17% in 12 h, and microwave irradiation, yield 18%–80%, requiring very low reaction times of 0.25–0.33 h. In addition, as a green-approach is offered, a convenient analysis, of the 12 green chemistry principles for the overall procedure was performed. Finally, since all the products are new, characterizations were carried out using common analytic procedures (1H, 11B, and 13C NMR, FAB+MS, HRMS, and IR. The accurate mass data of unexpected ions related to interactions between thioglycerol and the expected products, in the FAB+-mode, enabled unequivocal characterization of the target molecules.

  5. Simultaneous analysis and monitoring of 16 UV filters in cosmetics by high-performance liquid chromatography.

    Science.gov (United States)

    Kim, Dojung; Kim, Sangseop; Kim, Seol-A; Choi, Myoengsin; Kwon, Kyoung-Jin; Kim, Mijeong; Kim, Dong-Sup; Kim, Seung-Hee; Choi, Bo-Kyung

    2012-01-01

    Sixteen UV filters were simultaneously analyzed using the high-performance liquid chromatographic method. They were drometrizole (USAN Drometrizole), 4-methylbenzylidene camphor (USAN Enzacamene), menthyl anthranilate (USAN Menthyl anthranilate), benzophenone-3 (USAN Oxybenzone), benzophenone-8 (USAN Dioxybenzone), butyl methoxydibenzoylmethane (USAN Avobenzone), ethylhexyl triazone (USAN Octyl triazone), octocrylene (USAN Octocrylene), ethylhexyl dimethyl p-aminobenzoic acid (USAN Padimate O), ethylhexyl methoxycinnamate (USAN Octinoxate), p-aminobenzoic acid (USAN Aminobenzoic acid), 2-phenylbenzimidazole-5-sulfonic acid (USAN Ensulizole), isoamyl p-methoxycinnamate (USAN Amiloxate), and recent UV filters such as diethylhexyl butamidotriazone (USAN Iscotrizinol), methylene bis-benzotriazolyl tetramethylbutylphenol (USAN Bisoctrizole), and terephthalylidene dicamphor sulfonic acid (USAN Ecamsule). Separation of the UV filters was carried out in a C(18) column with a gradient of methanol-phosphate buffer, and the UV detection was at 300, 320, or 360 nm without any interference. The limits of detection were between 0.08 and 1.94 μg/ml, and the limits of quantitation were between 0.24 and 5.89 μg/ml. The extracting solvent for the UV filters was methanol, except for ethylhexyl triazone and methylene bis-benzotriazolyl tetramethylbutylphenol, which were prepared with tetrahydrofuran. The recoveries from spiked samples were between 94.90% and 116.54%, depending on the matrixes used. The developed method was applied to 23 sunscreens obtained from local markets, and the results were acceptable to their own criteria and to maximum authorized concentrations. Consequently, these results would provide a simple extracting method and a simultaneous determination for various UV filters, which can improve the quality control process as well as the environmental monitoring of sunscreens.

  6. Condensed, solution and gas phase behaviour of mono- and dinuclear 2,6-diacetylpyridine (dap) hydrazone copper complexes probed by X-ray, mass spectrometry and theoretical calculations.

    Science.gov (United States)

    Neto, Brenno A D; Viana, Barbara F L; Rodrigues, Thyago S; Lalli, Priscila M; Eberlin, Marcos N; da Silva, Wender A; de Oliveira, Heibbe C B; Gatto, Claudia C

    2013-08-28

    We describe the synthesis of novel mononuclear and dinuclear copper complexes and an investigation of their behaviour in solution using mass spectrometry (ESI-MS and ESI-MS/MS) and in the solid state using X-ray crystallography. The complexes were synthesized from two widely used diacetylpryridine (dap) ligands, i.e. 2,6-diacetylpyridinebis(benzoic acid hydrazone) and 2,6-diacetylpyridinebis(2-aminobenzoic acid hydrazone). Theoretical calculations (DFT) were used to predict the complex geometries of these new structures, their equilibrium in solution and energies associated with the transformations.

  7. Effect of some ultraviolet light absorbers on photo-stabilization of azadirachtin-A.

    Science.gov (United States)

    Deota, P T; Upadhyay, P R; Patel, K B; Mehta, K J; Varshney, A K; Mehta, M H

    2002-10-01

    The effect of photo-stabilization of Azadirachtin-A (Aza-A) was examined when exposed to sunlight and ultraviolet light in the presence of four structurally different ultraviolet stabilizers namely 4-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered at different time intervals from slides exposed to different light conditions with and without UV stabilizers as well as kinetic studies indicated that the addition of phenyl salicylate in methanolic solution of Aza-A (in 1:1 mole ratio) provides the best photo-stabilization of Aza-A molecule among the four UV stabilizers studied.

  8. Cocrystals and alloys of nitazoxanide: enhanced pharmacokinetics.

    Science.gov (United States)

    Suresh, Kuthuru; Mannava, M K Chaitanya; Nangia, Ashwini

    2016-03-18

    Two isomorphous cocrystals of nitazoxanide (NTZ) with p-aminosalicylic acid (PASA) and p-aminobenzoic acid (PABA) as well as their alloys were prepared by slurry and grinding techniques. The cocrystals exhibit faster dissolution rates and higher pharmacokinetic properties compared to the reference drug, and surprisingly the cocrystal alloy NTZ-PABA : NTZ-PASA (0.75 : 0.25) exhibited 4 fold higher bioavailability of NTZ in Sprague Dawley rats. This study opens the opportunity for cocrystal alloys as improved medicines.

  9. Ability of PABA to protect mammalian skin from ultraviolet light-induced skin tumors and actinic damage

    International Nuclear Information System (INIS)

    Snyder, D.S.; May, M.

    1975-01-01

    Application of 5% para-aminobenzoic acid (PABA) to hairless mice one hour prior to ultraviolet light (UVL) irradiation will almost totally protect these animals from developing tumors induced by chronic exposure to UVL in the 290 to 320 nm range in conjunction with a chemical carcinogen. Mice exposed to UVL and not protected by PABA developed primarily squamous cell carcinomas. Two months after cessation of chronic UVL exposure, the non-PABA-treated irradiated mouse skin appeared thickened, yellow, and wrinkled while showing elevated DNA synthesis, hyperplasia, hypergranulosis, and increased amounts of elastotic material. The PABA-treated skin was grossly normal

  10. 2-Amino­benzoic acid–4-[2-(pyridin-4-yl)eth­yl]pyridine (2/1)

    OpenAIRE

    Arman, Hadi D.; Tiekink, Edward R. T.

    2013-01-01

    The asymmetric unit of the title co-crystal, C12H12N2·2C7H7NO2, comprises a centrosymmetric 4-[2-(pyridin-4-yl)ethyl]pyridine molecule and a 2-aminobenzoic acid molecule in a general position. The acid has a small twist between the carboxylic acid residue and the ring [dihedral angle = 7.13 (6)°] despite the presence of an intramolecular N—H...O(carbonyl) hydrogen bond. Three-molecule aggregates are formed via O—H...N(pyridyl) hydrogen bonds, and these are connecte...

  11. Determination of 3-O- and 4-O-methylated monosaccharide constituents in snail glycans.

    Science.gov (United States)

    Stepan, Herwig; Bleckmann, Christina; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

    2010-07-02

    The N- and O-glycans of Arianta arbustorum, Achatina fulica, Arion lusitanicus and Planorbarius corneus were analysed for their monosaccharide pattern by reversed-phase HPLC after labelling with 2-aminobenzoic acid or 3-methyl-1-phenyl-2-pyrazolin-5-one and by gas chromatography-mass spectrometry. Glucosamine, galactosamine, mannose, galactose, glucose, fucose and xylose were identified. Furthermore, three different methylated sugars were detected: 3-O-methyl-mannose and 3-O-methyl-galactose were confirmed to be a common snail feature; 4-O-methyl-galactose was detected for the first time in snails. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. In silico design, synthesis, and assays of specific substrates for proteinase 3: influence of fluorogenic and charged groups.

    Science.gov (United States)

    Narawane, Shailesh; Budnjo, Adnan; Grauffel, Cédric; Haug, Bengt Erik; Reuter, Nathalie

    2014-02-13

    Neutrophil serine proteases are specific regulators of the immune response, and proteinase 3 is a major target antigen in antineutrophil cytoplasmic antibody-associated vasculitis. FRET peptides containing 2-aminobenzoic acid (Abz) and N-(2,4-dinitrophenyl)ethylenediamine (EDDnp) as fluorophore and quencher groups, respectively, have been widely used to probe proteases specificity. Using in silico design followed by enzymatic assays, we show that Abz and EDDnp significantly contribute to substrate hydrolysis by PR3. We also propose a new substrate specific for PR3.

  13. A Highly Stereocontrolled, One-Pot Approach toward Pyrrolobenzoxazinones and Pyrroloquinazolinones through a Lewis Acid-Catalyzed [3 + 2]-Cycloannulation Process.

    Science.gov (United States)

    Boomhoff, Michael; Ukis, Rostyslav; Schneider, Christoph

    2015-08-21

    We report herein a stereocontrolled [3 + 2]-cycloheteroannulation of bis-silyl dienediolate 1 with 2-aminobenzoic acid- and 2-aminobenzamide-derived imines to furnish highly substituted pyrrolo[1,2-a]benzoxazinones 3 and pyrrolo[1,2-a]quinazolinones 4, respectively, in good overall yields. This one-pot process rapidly generates molecular complexity and comprises a Lewis acid-catalyzed, vinylogous Mannich reaction of 1 followed by an intramolecular N,O-acetal- and N,N-aminal formation, respectively, which proceeds with good to excellent stereocontrol.

  14. Antibiotics in the chemical communication of fungi.

    Science.gov (United States)

    Kettering, Melanie; Sterner, Olov; Anke, Timm

    2004-01-01

    In dual cultures Oudemansiella mucida and Xerula melanotricha (basidiomycetes) react to the presence of living Penicillium notatum or P. turbatum with an increased production of strobilurin A (1) or X (2). P. notatum in turn reacts to the two basidiomycetes or their antibiotic strobilurin A alone with the production of N-(2-hydroxypropanoyl)-2-aminobenzoic acid amide (3) or chrysogine (4). P. melinii and P. urticae overgrow O. mucida due to complete resistance to strobilurin A. P. brevicompactum, P. citrinum, P. janczewskii and the other Penicillium strains are all sensitive but apparently do not induce O. mucida to produce the amounts of strobilurin A needed to inhibit their growth.

  15. 2-Amino­benzoic acid–4,4′-bi­pyridine (2/1)

    OpenAIRE

    Arman, Hadi D.; Tiekink, Edward R. T.

    2013-01-01

    The asymmetric unit of title co-crystal, C10H8N2·2C7H7NO2, comprises a centrosymmetric 4,4′-bipyridine molecule, and a 2-aminobenzoic acid molecule in a general position. The latter is effectively planar [C—C—C—O torsion angle = 5.0 (3)°] owing to an intramolecular N—H...O(carbonyl) hydrogen bond. Three-molecule aggregates are formed via O—H...N(pyridyl) hydrogen bonds and these are connected into supramolecular layers in the bc plane by N&#...

  16. Targeting Ligand Dependent and Ligand Independent Androgen Receptor Signaling in Prostate Cancer

    Science.gov (United States)

    2014-10-01

    flanking residues around the LXXLL motif to our lead D2 compound. * To facilitate the synthesis of tris-benzamide analogues designed to target AR...we used only alkyl groups such as n- propyl , isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl and isopentyl groups for side chain diversity of the...by reacting 3-alkoxy-4-nitrobenzoyl chlorides 2 with methyl 3-alkoxy-4-aminobenzoates 3 (Scheme 1).21 NO2 O NHO R2 O R1 O O NH2 O R1 O Oa N H NO2 O

  17. Photostabilization of doxorubicin hydrochloride with radioprotective and photoprotective agents: Potential mechanism for enhancing chemotherapy during radiotherapy

    International Nuclear Information System (INIS)

    Habib, M.J.; Asker, A.F.

    1989-01-01

    p-Aminobenzoic acid (PABA), urocanic acid, and sodium urate were found to significantly enhance the photostability of doxorubicin hydrochloride [adriamycin, (ADR)]. d1-Methionine, thiourea, and glycine also increased the photostability of this drug, but to a lesser degree. Sodium thiosulfate on the other hand, was found to be detrimental to the photostability of ADR. The photostabilizing effect of PABA was found to increase with increase of its concentration and was influenced by the pH and the buffer species of the vehicle. The findings would have an impact on the enhancement of therapeutic efficacy of adriamycin when administered during radiation therapy

  18. Identification of a 23 kDa protein from maize photoaffinity-labelled with 5-azido-[7-3H]indol-3-ylacetic acid.

    OpenAIRE

    Feldwisch, J; Zettl, R; Campos, N; Palme, K

    1995-01-01

    A 23 kDa protein (p23) was identified in microsomal extracts from maize coleoptiles by photoaffinity labelling with 5-azido-[7-3H]indol-3-ylacetic acid ([3H]N3IAA). Labelling of p23 was blocked by unlabelled IAA, N3IAA, indol-3-ylbutyric acid and indol-3-yl-lactate. In addition, labelling was efficiently decreased by tryptophan, as well as by the scavenger p-aminobenzoic acid. Labelling was, however, not affected by synthetic auxins such as 1-naphthylacetic acid or 2,4-dichlorophenoxyacetic a...

  19. Copper and dyes enhance laccase production in gamma-proteobacterium JB.

    Science.gov (United States)

    Malhotra, Kanam; Sharma, Prince; Capalash, Neena

    2004-07-01

    Laccase production in gamma-proteobacterium JB was enhanced 13-fold by adding 0.1 mM CuSO(4) 24 h after the onset of growth. Ethidium bromide (2.5 microM), Malachite Green, Phenol Red and Thymol Blue (10 microM each) enhanced laccase production 17-, 19-, 4- and 2-fold, respectively. Among the fourteen aromatic/organic compounds tried, p-aminobenzoic acid and an industrial effluent, from where the organism was isolated, showed 1.2- and 1.26-fold increases in production.

  20. The Adsorption of Pb, Zn, Cu, Ni, and Cd by Modified Ligand in a Single Component Aqueous Solution: Equilibrium, Kinetic, Thermodynamic, and Desorption Studies

    Directory of Open Access Journals (Sweden)

    E. Igberase

    2017-01-01

    Full Text Available In this investigation, an amino functionalized adsorbent was developed by grafting 4-aminobenzoic acid onto the backbone of cross-linked chitosan beads. The 3 sets of beads including chitosan (CX, glutaraldehyde cross-linked chitosan (CCX, and 4-aminobenzoic acid grafted cross-linked chitosan (FGCX were characterized by FTIR, XRD, SEM, and TGA. The water content and amine concentration of FGCX were determined. The effect of adsorption parameters was studied and the optimum was used for further studies. Equilibrium data was obtained from the adsorption experiment carried out at different initial concentration; the data were applied in isotherm, thermodynamics, and kinetic studies. The Langmuir and Dubinin-Kaganer-Radushkevich (DKR models were successful in describing the isotherm data for the considered metal ions while the Freundlich and Temkin model fit some of the considered metal ions. Pseudo-second-order and intraparticle model described the kinetic data quite well. Thermodynamic parameters such as Gibb’s free energy change (ΔGo, enthalpy change (ΔHo, and entropy change (ΔSo were calculated and the results showed that the adsorption of Pb, Cu, Ni, Zn, and Cd ions onto FGCX is spontaneous and endothermic in nature. Regeneration of the spent adsorbent was efficient for the considered metal ions.

  1. Comparison of inhibition effects of some benzoic acid derivatives on sheep heart carbonic anhydrase

    Science.gov (United States)

    Kiliç, Deryanur; Yildiz, Melike; Şentürk, Murat; Erdoǧan, Orhan; Küfrevioǧlu, Ömer Irfan

    2016-04-01

    Carbonic anhydrase (CA) is a family of metalloenzymes that requires Zn as a cofactor and catalyze the quick conversion of CO2 to HCO3- and H+. Inhibitors of the carbonic anhydrases (CAs) have medical usage of significant diseases such as glaucoma, epilepsy, gastroduodenal ulcers, acid-base disequilibria and neurological disorders. In the present study, inhibition of CA with some benzoic derivatives (1-6) were investigated. Sheep heart CA (shCA) enzyme was isolated by means of designed affinity chromatography gel (cellulose-benzyl-sulfanylamide) 42.45-fold in a yield of 44 % with 564.65 EU/mg. Purified shCA enzyme was used in vitro studies. In the studies, IC50 values were calculated for 3-aminobenzoic acid (1), 4-aminobenzoic acid (2), 2-hydroxybenzoic acid (3), 2-benzoylbenzoic acid (4), 2,3-dimethoxybenzoic acid (5), and 3,4,5-trimethoxybenzoic acid (6), showing the inhibition effects on the purified enzyme. Such molecules can be used as pioneer for discovery of novel effective CA inhibitors for medicinal chemistry applications.

  2. Dual modifications strategy to quantify neutral and sialylated N-glycans simultaneously by MALDI-MS.

    Science.gov (United States)

    Zhou, Hui; Warren, Peter G; Froehlich, John W; Lee, Richard S

    2014-07-01

    Differences in ionization efficiency among neutral and sialylated glycans prevent direct quantitative comparison by their respective mass spectrometric signals. To overcome this challenge, we developed an integrated chemical strategy, Dual Reactions for Analytical Glycomics (DRAG), to quantitatively compare neutral and sialylated glycans simultaneously by MALDI-MS. Initially, two glycan samples to be compared undergo reductive amination with 2-aminobenzoic acid and 2-(13)[C6]-aminobenzoic acid, respectively. The different isotope-incorporated glycans are then combined and subjected to the methylamidation of the sialic acid residues in one mixture, homogenizing the ionization responses for all neutral and sialylated glycans. By this approach, the expression change of relevant glycans between two samples is proportional to the ratios of doublet signals with a static 6 Da mass difference in MALDI-MS and the change in relative abundance of any glycan within samples can also be determined. The strategy was chemically validated using well-characterized N-glycans from bovine fetuin and IgG from human serum. By comparing the N-glycomes from a first morning (AM) versus an afternoon (PM) urine sample obtained from a single donor, we further demonstrated the ability of DRAG strategy to measure subtle quantitative differences in numerous urinary N-glycans.

  3. A comparative study of monosaccharide composition analysis as a carbohydrate test for biopharmaceuticals.

    Science.gov (United States)

    Harazono, Akira; Kobayashi, Tetsu; Kawasaki, Nana; Itoh, Satsuki; Tada, Minoru; Hashii, Noritaka; Ishii, Akiko; Arato, Teruyo; Yanagihara, Shigehiro; Yagi, Yuki; Koga, Akiko; Tsuda, Yuriko; Kimura, Mikiko; Sakita, Masashi; Kitamura, Satoshi; Yamaguchi, Hideto; Mimura, Hisashi; Murata, Yoshimi; Hamazume, Yasuki; Sato, Takayuki; Natsuka, Shunji; Kakehi, Kazuaki; Kinoshita, Mitsuhiro; Watanabe, Sakie; Yamaguchi, Teruhide

    2011-05-01

    The various monosaccharide composition analysis methods were evaluated as monosaccharide test for glycoprotein-based pharmaceuticals. Neutral and amino sugars were released by hydrolysis with 4-7N trifluoroacetic acid. The monosaccharides were N-acetylated if necessary, and analyzed by high-performance liquid chromatography (HPLC) with fluorometric or UV detection after derivatization with 2-aminopyridine, ethyl 4-aminobenzoate, 2-aminobenzoic acid or 1-phenyl-3-methyl-5-pyrazolone, or high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Sialic acids were released by mild acid hydrolysis or sialidase digestion, and analyzed by HPLC with fluorometric detection after derivatization with 1,2-diamino-4,5-methylenedioxybenzene, or HPAEC-PAD. These methods were verified for resolution, linearity, repeatability, and accuracy using a monosaccharide standard solution, a mixture of epoetin alfa and beta, and alteplase as models. It was confirmed that those methods were useful for ensuring the consistency of glycosylation. It is considered essential that the analytical conditions including desalting, selection of internal standards, release of monosaccharides, and gradient time course should be determined carefully to eliminate interference of sample matrix. Various HPLC-based monosaccharide analysis methods were evaluated as a carbohydrate test for glycoprotein pharmaceuticals by an inter-laboratory study. Copyright © 2011 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

  4. Induction of lethal and genetic damage by vacuum-ultraviolet (163 nm) irradiation of aqueous suspensions of yeast cells

    International Nuclear Information System (INIS)

    Ito, T.; Kobayashi, K.

    1976-01-01

    Yeast cells suspended in distilled water were irradiated with monochromatic 163 nm photons by immersing a specially designed discharge tube into the suspension. This was thought to be a useful means of investigating in vivo effects of radiation-induced water radicals on well cells in the complete absence of ionic species, since 163 nm photons can dissociate water only via excitation. These experiments showed that the water radicals (excluding e/sub aq/ - ) exerted both lethal and genetic (gene-conversion) effects quite potently, and the characteristic protection against these effects was observable when 2-mercaptoethanol or, in particular, p-aminobenzoic acid, a specific scavenger for OH radicals, was added to the medium prior to irradiation. Nearly complete protection from both lethal and genetic effects was observed in some cases with p-aminobenzoic acid. These results establish unequivocally that the OH radical, and not the hydrogen atom (H radical), possesses the damaging potency in the cell. Comparisons with γ-ray experiments revealed several differences between 163 nm photons and γ rays in the protective actions of radical scavengers, which may be attributable to reactive species other than OH radicals produced by the γ rays

  5. Differentiation of isomeric N-glycan structures by normal-phase liquid chromatography-MALDI-TOF/TOF tandem mass spectrometry.

    Science.gov (United States)

    Maslen, Sarah; Sadowski, Pawel; Adam, Alex; Lilley, Kathryn; Stephens, Elaine

    2006-12-15

    The detailed characterization of protein N-glycosylation is very demanding given the many different glycoforms and structural isomers that can exist on glycoproteins. Here we report a fast and sensitive method for the extensive structure elucidation of reducing-end labeled N-glycan mixtures using a combination of capillary normal-phase HPLC coupled off-line to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and TOF/TOF-MS/MS. Using this method, isobaric N-glycans released from honey bee phospholipase A2 and Arabidopsis thaliana glycoproteins were separated by normal-phase chromatography and subsequently identified by key fragment ions in the MALDI-TOF/TOF tandem mass spectra. In addition, linkage and branching information were provided by abundant cross-ring and "elimination" fragment ions in the MALDI-CID spectra that gave extensive structural information. Furthermore, the fragmentation characteristics of N-glycans reductively aminated with 2-aminobenzoic acid and 2-aminobenzamide were compared. The identification of N-glycans containing 3-linked core fucose was facilitated by distinctive ions present only in the MALDI-CID spectra of 2-aminobenzoic acid-labeled oligosaccharides. To our knowledge, this is the first MS/MS-based technique that allows confident identification of N-glycans containing 3-linked core fucose, which is a major allergenic determinant on insect and plant glycoproteins.

  6. Gas-generated thermal oxidation of a coordination cluster for an anion-doped mesoporous metal oxide.

    Science.gov (United States)

    Hirai, Kenji; Isobe, Shigehito; Sada, Kazuki

    2015-12-18

    Central in material design of metal oxides is the increase of surface area and control of intrinsic electronic and optical properties, because of potential applications for energy storage, photocatalysis and photovoltaics. Here, we disclose a facile method, inspired by geochemical process, which gives rise to mesoporous anion-doped metal oxides. As a model system, we demonstrate that simple calcination of a multinuclear coordination cluster results in synchronic chemical reactions: thermal oxidation of Ti8O10(4-aminobenzoate)12 and generation of gases including amino-group fragments. The gas generation during the thermal oxidation of Ti8O10(4-aminobenzoate)12 creates mesoporosity in TiO2. Concurrently, nitrogen atoms contained in the gases are doped into TiO2, thus leading to the formation of mesoporous N-doped TiO2. The mesoporous N-doped TiO2 can be easily synthesized by calcination of the multinuclear coordination cluster, but shows better photocatalytic activity than the one prepared by a conventional sol-gel method. Owing to an intrinsic designability of coordination compounds, this facile synthetic will be applicable to a wide range of metal oxides and anion dopants.

  7. Gene-enriched draft genome of the cattle tick Rhipicephalus microplus: assembly by the hybrid Pacific Biosciences/Illumina approach enabled analysis of the highly repetitive genome.

    Science.gov (United States)

    Barrero, Roberto A; Guerrero, Felix D; Black, Michael; McCooke, John; Chapman, Brett; Schilkey, Faye; Pérez de León, Adalberto A; Miller, Robert J; Bruns, Sara; Dobry, Jason; Mikhaylenko, Galina; Stormo, Keith; Bell, Callum; Tao, Quanzhou; Bogden, Robert; Moolhuijzen, Paula M; Hunter, Adam; Bellgard, Matthew I

    2017-08-01

    The genome of the cattle tick Rhipicephalus microplus, an ectoparasite with global distribution, is estimated to be 7.1Gbp in length and consists of approximately 70% repetitive DNA. We report the draft assembly of a tick genome that utilized a hybrid sequencing and assembly approach to capture the repetitive fractions of the genome. Our hybrid approach produced an assembly consisting of 2.0Gbp represented in 195,170 scaffolds with a N50 of 60,284bp. The Rmi v2.0 assembly is 51.46% repetitive with a large fraction of unclassified repeats, short interspersed elements, long interspersed elements and long terminal repeats. We identified 38,827 putative R. microplus gene loci, of which 24,758 were protein coding genes (≥100 amino acids). OrthoMCL comparative analysis against 11 selected species including insects and vertebrates identified 10,835 and 3,423 protein coding gene loci that are unique to R. microplus or common to both R. microplus and Ixodes scapularis ticks, respectively. We identified 191 microRNA loci, of which 168 have similarity to known miRNAs and 23 represent novel miRNA families. We identified the genomic loci of several highly divergent R. microplus esterases with sequence similarity to acetylcholinesterase. Additionally we report the finding of a novel cytochrome P450 CYP41 homolog that shows similar protein folding structures to known CYP41 proteins known to be involved in acaricide resistance. Copyright © 2017 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

  8. Benzoic Acid Derivatives with Trypanocidal Activity: Enzymatic Analysis and Molecular Docking Studies toward Trans-Sialidase

    Directory of Open Access Journals (Sweden)

    Muhammad Kashif

    2017-10-01

    Full Text Available Chagas, or American trypanosomiasis, remains an important public health problem in developing countries. In the last decade, trans-sialidase has become a pharmacological target for new anti-Chagas drugs. In this work, the aims were to design and find a new series of benzoic acid derivatives as trans-sialidase (TS inhibitors and anti-trypanosomal agents. Three compounds (14, 18, and 19 sharing a para-aminobenzoic acid moiety showed more potent trypanocidal activity than the commercially available drugs nifurtimox and benznidazole in both strains: the lysis concentration of 50% of the population (LC50 was <0.15 µM on the NINOA strain, and LC50 < 0.22 µM on the INC-5 strain. Additionally, compound 18 showed a moderate inhibition (47% on the trans-sialidase enzyme and a binding model similar to DANA (pattern A.

  9. Gas-phase acylation of aminopropyl-silica gel in the synthesis of some chemically bonded silica materials for analytical applications

    International Nuclear Information System (INIS)

    Basiuk, Vladimir; Khil'chevskaya, E.G.

    1991-01-01

    Gas-phase acylation of aminopropyl-silica gel with aliphatic dicarboxylic (succinic, adipic and sebacic) and 4-aminobenzoic acids is proposed as a rapid and efficient one-step method for the synthesis of carboxyalkyl- and 4-aminophenylamidopropyl-silica gels, usually used as zwitterion exchangers for liquid chromatography and matrices for multi-step syntheses of silica-bound aromatic azo reagents for the sorption and chromatographic separation of metal ions. Acylation degrees of 59-90% are achieved after 0.5 h. IR spectra of the acylation products and near-UV-visible spectra for bonded aromatic azo compounds, based on 4-aminobenzamidopropyl-silica gel, are presented. Some positive and negative aspects of the gas-phase acylation are discussed. (author). 34 refs.; 2 figs.; 2 tabs

  10. Effect of ultraviolet light absorbers on photostabilization of azadirachtin-A in solution (part: II).

    Science.gov (United States)

    Deota, P T; Upadhyay, P R; Valodkar, V B

    2003-01-01

    The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1:1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.

  11. Synthesis and Characterization of Some New Thermal Stable Polymers - Polymerization of N-[4-N´ -(Benzylamino-carbonylphenyl]maleimide

    Directory of Open Access Journals (Sweden)

    B. L. Hiran

    2007-01-01

    Full Text Available This article describes the synthesis and characterization of homopolymer (H-BCPM of N-[4-N'-(benzylamino-carbonyl phenyl] maleimide (N-BACPMI and copolymer (C-BCPM of N-BACPMI with n-butyl acrylate (BA. The new monomer was synthesized from p-aminobenzoic acid, maleic anhydride and benzylamine. The homopolymerization of N-BACPMI is initiated by free radical using AIBN in THF solvent at 65°C. Radical copolymerization of N-BACPMI with BA, initiated by AIBN, was performed in THF solvent using equimolar amount. Effect of the different free radical initiator AIBN, BPO and solvents p-Dioxane, THF, DMF and DMSO was studied. Homopolymer and Copolymer were characterized by intrinsic viscosity, solubility test, FT-IR, 1H-NMR spectral analysis and elemental analysis. Thermal behaviour was studied by Thermo gravimetric analysis.

  12. Pancreatic exocrine function testing

    International Nuclear Information System (INIS)

    Goff, J.S.

    1981-01-01

    It is important to understand which pancreatic function tests are available and how to interpret them when evaluating patients with malabsorption. Available direct tests are the secretin stimulation test, the Lundh test meal, and measurement of serum or fecal enzymes. Indirect tests assess pancreatic exocrine function by measuring the effect of pancreatic secretion on various nutrients. These include triglycerides labeled with carbon 14, cobalamin labeled with cobalt 57 and cobalt 58, and para-aminobenzoic acid bound to a dipeptide. Of all these tests the secretin stimulation test is the most accurate and reliable if done by experienced personnel. However, the indirect tests are simpler to do and appear to be comparable to the secretin test at detecting pancreatic exocrine insufficiency. These indirect tests are becoming clinically available and clinicians should familiarize themselves with the strengths and weaknesses of each

  13. Facile synthesis of RuII Schiff base complexes: spectral characterization and antimicrobial applications

    International Nuclear Information System (INIS)

    Arunachalam, S.; Padma Priya, N.; Shahul Meeran, H.

    2014-01-01

    Diamagnetic ruthenium (II) complexes of the type (RuCl (CO) (pyridine) (L)) (where L = monobasic tridentate Schiff base ligands) were synthesized by the reactions of Schiff bases derived from the reactions of o-aminobenzoic acid and Knovenegal condensate of β - ketoesters and appropriate ruthenium metal precursor (RuHCl (CO) (PPh 3 ) 2 (py)). Elemental analyses and spectral (FT-IR, UV-Vi s and 1 H, 31 P NMR) studies of all the new synthesized complexes suggest the presence of an octahedral environment around the Ru II ion. Cyclic voltammograms of all the complexes display oxidation and reduction potentials. Superoxide dismutase activity (SOD) of these complexes has also been examined. These complexes were also subjected to study their biocidal activity against Staphylococcus epidermidis, Escherichia coli, Botrytis cinerea and Aspergillus niger. (author)

  14. Cytotoxic evaluation upon cis-platinum aminodiacetic acid complexes

    International Nuclear Information System (INIS)

    Almah binti Awaluddin; Parsons, Peter G.; Lean, Jenny M.; Jacobs, Jeffrey J.

    1990-01-01

    Cytoxic study of cis-platinum aminodiacetic acid complexes. Three novel platinum complexes have been synthesised and characterised by Awaluddin et. al (1987). This introduces a new area of radiopharmaceuticals based on technician and platinum. Cytotoxic studies were conducted on these complexes using four different types of cell lines. The para amina was found to be highly active against multi-resistant ovarian tumor cells compared to normal cells (fibroblast) and other tumor cells. The chemical structure of para-amina appears to be devoid of any functional group resembling current antitumor drugs except for a distant similarity to metotrexate with respect to the p-aminobenzoic type structure. However cell lines such as Hela and MM 253c-1, which is sensitive to metotrexate, were not sensitive to the para amina. Preliminary studies have shown that cells are blocked in the G phase of the cell cycle, suggesting an antimetabolite effect

  15. Synthesis, structure, and magnetic properties of two 1-D helical coordination polymeric Cu(II) complexes

    Science.gov (United States)

    Bian, He-Dong; Yang, Xiao-E.; Yu, Qing; Chen, Zi-Lu; Liang, Hong; Yan, Shi-Ping; Liao, Dai-Zheng

    2008-01-01

    Two helical coordination polymeric copper(II) complexes bearing amino acid Schiff bases HL or HL', which are condensed from 2-hydroxy-1-naphthaldehyde with 2-aminobenzoic acid or L-valine, respectively, have been prepared and characterised by X-ray crystallography. In [CuL] n ( 1) the copper(II) atoms are bridged by syn- anti carboxylate groups giving infinite 1-D right-handed helical chains which are further connected by weak C-H⋯Cu interactions to build a 2-D network. While in [CuL'] n ( 2) the carboxylate group acts as a rare monatomic bridge to connect the adjacent copper(II) atoms leading to the formation of a left-handed helical chain. Magnetic susceptibility measurements indicate that 1 exhibits weak ferromagnetic interactions whereas an antiferromagnetic coupling is established for 2. The magnetic behavior can be satisfactorily explained on the basis of the structural data.

  16. Preparation of one-vial reduced anti-CEA kit

    International Nuclear Information System (INIS)

    Hamada, Elena Setuko; Muramoto, Emiko; Shiraishi, Emilia Mayumi; Silva, Licia Maria Britto da; Martins, Heidi Pinto; Silva, Constanca Pagano Goncalves da

    1996-01-01

    A rapid and reliable instant reduced anti-CEA lyophilized kit for labelling with 99m Tc was developed. Each vial contains 0.5 mg of reduced anti-CEA, 40 μg of mendronate (MDP), 2.75 μg stannous fluoride (Sn F 2 ) and 15 μ g p-aminobenzoic acid (PABA). Labeling efficiency and stability were higher than 95% and were determined by instant paper chromatography. Biodistribution studies were performed in normal isogenic BALB/c mice at 4,6 and 24 hours after intravenous administration of the radiolabelled product. The maximum amount of activity was accumulated in the liver followed by intestines and kidneys. (author)

  17. A novel approach to isoindolo[2,1-a]indol-6-ones.

    Science.gov (United States)

    Duncanson, Philip; Cheong, Yuen-Ki; Motevalli, Majid; Griffiths, D Vaughan

    2012-06-07

    A convenient route to isoindolo[2,1-a]indol-6-ones has been developed starting from the appropriate 2-(N-phthaloyl)benzoic acids. Formation of the acid chlorides with thionyl chloride followed by heating with triethyl phosphite in a suitable solvent resulted in a multistep reaction giving tetracyclic β-ketophosphonates that on reduction with sodium borohydride gave the required indolones in good overall yields. Analogous β-ketophosphonates were also prepared starting with N,N-(1,8-naphthaloyl)-2-aminobenzoic acid and 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzoic acids although of these only the naphthaloyl product could be reduced with sodium borohydride without cleaving the amide bond in the ring system.

  18. Astatine-211 labelled proteins and their stability in vivo

    International Nuclear Information System (INIS)

    Yi Changhou; Jin Jannan; Zhang Shuyuan; Wang Ketai; Zhang Dayuan; Zhou Maolun

    1989-01-01

    211 At or 131 I labelled proteins, e.g. 211 At-IgG or 211 At-BSA (bovine serum albumin) were prepared by 211 At reaction with the diazo-compound of para-aminobenzoic acid, which is then conjugated with IgG or BSA via an acylation reaction. The 211 At-carbon bond was found metabolically stable under in vivo conditions. For the labelling of proteins with 211 At or 131 I, other methods of direct oxidation are also described. The results show that for the labelling of proteins with 211 At, high rate of incorporation can be obtained with hydrogen peroxide as oxidant, but the labelling of proteins with 131 I is more favourable with the strong oxidant Chloramine-T. (author) 12 refs.; 6 figs

  19. Dual fluorescence of N-phenylanthranilic acid: Effect of solvents, pH and β-cyclodextrin

    Science.gov (United States)

    Rajendiran, N.; Balasubramanian, T.

    2007-11-01

    Spectral characteristics of N-phenylanthranilic acid (NPAA) have been studied in different solvents, pH and β-cyclodextrin (β-CD) and compared with anthranilic acid (2-aminobenzoic acid, 2ABA). In all solvents a dual fluorescence is observed in NPAA, whereas 2ABA gives single emission. Combining the results observed in the absorption, fluorescence emission and fluorescence excitation spectra, it is found that strong intramolecular hydrogen bonding (IHB) interactions present in NPAA molecule. The inclusion complex of NPAA with β-CD is analysed by UV-vis, fluorimetry, FT-IR, 1H NMR, scanning electron microscope and AM 1 method. The above spectral studies show that NPAA forms a 1:1 inclusion complex with β-CD and COOH group present in the β-CD cavity. A mechanism is proposed to explain the inclusion process.

  20. Investigating tautomeric polymorphism in crystalline anthranilic acid using terahertz spectroscopy and solid-state density functional theory.

    Science.gov (United States)

    Delaney, Sean P; Witko, Ewelina M; Smith, Tiffany M; Korter, Timothy M

    2012-08-02

    Terahertz spectroscopy is sensitive to the interactions between molecules in the solid-state and recently has emerged as a new analytical tool for investigating polymorphism. Here, this technique is applied for the first time to the phenomenon of tautomeric polymorphism where the crystal structures of anthranilic acid (2-aminobenzoic acid) have been investigated. Three polymorphs of anthranilic acid (denoted Forms I, II and III) were studied using terahertz spectroscopy and the vibrational modes and relative polymorph stabilities analyzed using solid-state density functional theory calculations augmented with London dispersion force corrections. Form I consists of both neutral and zwitterionic molecules and was found to be the most stable polymorph as compared to Forms II and III (both containing only neutral molecules). The simulations suggest that a balance between steric interactions and electrostatic forces is responsible for the favoring of the mixed neutral/zwitterion solid over the all neutral or all zwitterion crystalline arrangements.

  1. A polymer supported Cu(I) catalyst for the 'click reaction' in aqueous media.

    Science.gov (United States)

    Ul Islam, Rafique; Taher, Abu; Choudhary, Meenakshi; Witcomb, Michael J; Mallick, Kaushik

    2015-01-21

    Polymer stabilized monovalent copper has been synthesized using an in situ chemical transformation route and was characterized by means of different microscopic, optical and surface characterization techniques, which offered information about the chemical structure of the polymer and the morphology of the complex. The supramolecular material, Cu(i)-poly(2-aminobenzoic acid), denoted Cu(i)-pABA, showed catalytic activity for the cycloaddition reaction between terminal alkynes and azides to synthesize 1,2,3-triazoles with excellent yields. The catalyst was recovered from the reaction mixture and recycled several times without an appreciable loss of catalytic activity. The whole strategy was done under ambient conditions and in the presence of water as a solvent.

  2. Non-isothermal degradation and evaluation of kinetic parameters of some Schiff base metal complexes

    International Nuclear Information System (INIS)

    Mishra, A.P.; Soni, Monika

    2008-01-01

    Thermal decomposition of VO (II)-methyl isobutyl ketone-nicotinamide, VO (II)-2-furfurylidine-3,4-dichloroaniline, Co(II)-4-dimethyl amino benzylidine-3-chloro-4-fluoroaniline, VO(II)-2-pyridine carboxylidine-4-aminobenzoic acid complexes have been carried out by thermogravimetric method. The TG curves of complexes were recorded at a uniform rate of 20 deg C/min in nitrogen. The thermogram of the three VO(II) complexes exhibit single stage decomposition whereas the Co(II) complex shows a double stage decomposition. Various kinetic parameters i. e., energy of activation (E), entropy (AS) and frequency factor (Z) have been evaluated by using Coats-Redfern and Piloyan-Novikova equations and their comparable values are reported. The order of thermal stability of first decomposition stage is as: 4=2>1>3. (author)

  3. Electron Detachment Dissociation (EDD) of Fluorescently Labeled Sialylated Oligosaccharides

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2012-01-01

    We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared to IRMPD. Neutral losses and satellite ions such as C – 2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared to 2-AA labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. PMID:22120881

  4. New synthesis of gold nanocorals using a diazonium compound, and their application to an electrochemiluminescent assay of hydrogen peroxide

    International Nuclear Information System (INIS)

    Xu, Min; Qi, Wenjing; Zhang, Ling; Lai, Jianping; Aziz-ur-Rehman; Majeed, Saadat; Xu, Guobao

    2014-01-01

    The reaction of hydrogen tetracholoroaurate, sodium borohydride and the diazonium compound prepared from 4-aminobenzoic acid results in the formation of gold nanocorals (Au-NCs) for the first time. Scanning electron microscopy images and transmission electron microscopy images show that the Au-NCs are composed of nanowires with a diameter of 5.3 nm. A glassy carbon electrode modified with Au-NCs is found to trigger intense electrochemiluminescence of the luminol/H 2 O 2 system at a potential of −0.13 V. The effect was exploited to determine H 2 O 2 in the 0.1 to 100 μM concentration range with a 30 nM detection limit. (author)

  5. Stable Isotope Quantitative N-Glycan Analysis by Liquid Separation Techniques and Mass Spectrometry.

    Science.gov (United States)

    Mittermayr, Stefan; Albrecht, Simone; Váradi, Csaba; Millán-Martín, Silvia; Bones, Jonathan

    2017-01-01

    Liquid phase separation analysis and subsequent quantitation remains a challenging task for protein-derived oligosaccharides due to their inherent structural complexity and diversity. Incomplete resolution or co-detection of multiple glycan species complicates peak area-based quantitation and associated statistical analysis when optical detection methods are used. The approach outlined herein describes the utilization of stable isotope variants of commonly used fluorescent tags that allow for mass-based glycan identification and relative quantitation following separation by liquid chromatography (LC) or capillary electrophoresis (CE). Comparability assessment of glycoprotein-derived oligosaccharides is performed by derivatization with commercially available isotope variants of 2-aminobenzoic acid or aniline and analysis by LC- and CE-mass spectrometry. Quantitative information is attained from the extracted ion chromatogram/electropherogram ratios generated from the light and heavy isotope clusters.

  6. Phase transition and intramolecular hydrogen bonding in nitro derivatives of ortho-hydroxy acetophenones

    Science.gov (United States)

    Filarowski, A.; Kochel, A.; Koll, A.; Bator, G.; Mukherjee, S.

    2006-03-01

    The crystal structures of two ortho-hydroxy aryl ketones (5-chloro-3-nitro-2-hydroxyacetophenone, 5-methyl-3-nitro-2-hydroxyacetophenone and the complex 5-chloro-3-nitro-2-hydroxyacetophenone with 2-aminobenzoic acid (anthranilic acid)) were determined by X-ray diffraction. The existence of an intramolecular hydrogen bond of enol character between the hydroxyl and acetyl groups was found by the X-ray method. The enol character was also confirmed by DFT (B3LYP/6-31+G(d,p)) calculations. A phase transition was found at 138 K in 5-chloro-3-nitro-2-hydroxyacetophenone. This phase transition was investigated by differential scanning calorimetry (DSC), dilatometry, and the dielectric method. A study of the nitro-group dynamics in the ortho-hydroxy acetophenones was carried out with DFT (B3LYP/6-31+G(d,p)) calculations.

  7. Pharmacological and spectral studies of synthetic biomimetic copper complexes derived from 3-hydroxyflavone derivatives as anti-inflammatory agents

    Directory of Open Access Journals (Sweden)

    K. Nagashri

    2016-09-01

    Full Text Available Novel biomimetic ligands were synthesized by the condensation of 3-hydroxyflavone, 2-aminophenol(L1/2-aminobenzoic acid (L2 and-aminothiazole (L3. Their Cu(II complexes have also been synthesized and characterized on the basis of 1H NMR, IR, UV–Vis spectra, elemental analyses, molar conductivity, ESR, electrochemical behaviour and thermal analyses. The antimicrobial activities (MIC values of the ligands, copper complexes and standard drugs have been evaluated using the serial dilution technique against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans. The anti-inflammatory and SOD activities of the investigated compounds are also promising and allow the selection of a lead compound for further biological studies.

  8. Dual fluorescence of N-phenylanthranilic acid: Effect of solvents, pH and beta-cyclodextrin.

    Science.gov (United States)

    Rajendiran, N; Balasubramanian, T

    2007-11-01

    Spectral characteristics of N-phenylanthranilic acid (NPAA) have been studied in different solvents, pH and beta-cyclodextrin (beta-CD) and compared with anthranilic acid (2-aminobenzoic acid, 2ABA). In all solvents a dual fluorescence is observed in NPAA, whereas 2ABA gives single emission. Combining the results observed in the absorption, fluorescence emission and fluorescence excitation spectra, it is found that strong intramolecular hydrogen bonding (IHB) interactions present in NPAA molecule. The inclusion complex of NPAA with beta-CD is analysed by UV-vis, fluorimetry, FT-IR, (1)H NMR, scanning electron microscope and AM 1 method. The above spectral studies show that NPAA forms a 1:1 inclusion complex with beta-CD and COOH group present in the beta-CD cavity. A mechanism is proposed to explain the inclusion process.

  9. 2-Pyridylfuran: a new fluorescent tag for the analysis of carbohydrates.

    Science.gov (United States)

    Cai, Zhi Peng; Hagan, Andrew Kevin; Wang, Mao Mao; Flitsch, Sabine Lahja; Liu, Li; Voglmeir, Josef

    2014-05-20

    We herein report the use of 1,3-di(2-pyridyl)-1,3-propanedione (DPPD) as a fluorogenic labeling reagent for sugars. Reaction of DPPD with the anomeric carbon affords a fluorescent 2-pyridylfuran (2-PF) moiety that permits the sensitive HPLC-based detection of monosaccharides. 2-PF-labeled monosaccharides can be easily separated and analyzed from mixtures thereof, and the reported protocol compares favorably with established labeling reagents such as 2-aminobenzoic acid (2-AA) and 1-phenyl-3-methyl-5-pyrazolone (PMP), ultimately allowing subfemtomole detection of the galactose-derived product. Furthermore, we demonstrate the application of DPPD in the labeling of monosaccharides in complex biological matrices such as blood and milk samples. We envisage that DPPD will prove to be an excellent choice of labeling reagent in monosaccharide and carbohydrate analysis.

  10. Hydrogen-bonded co-crystal structure of benzoic acid and zwitterionic l-proline

    Directory of Open Access Journals (Sweden)

    Aaron M. Chesna

    2017-03-01

    Full Text Available The title compound [systematic name: benzoic acid–pyrrolidin-1-ium-2-carboxylate (1/1], C7H6O2·C5H9NO2, is an example of the application of non-centrosymmetric co-crystallization for the growth of a crystal containing a typically centrosymmetric component in a chiral space group. It co-crystallizes in the space group P212121 and contains benzoic acid and l-proline in equal proportions. The crystal structure exhibits chains of l-proline zwitterions capped by benzoic acid molecules which form a C(5[R33(11] hydrogen-bonded network along [100]. The crystal structure is examined and compared to that of a similar co-crystal containing l-proline zwitterions and 4-aminobenzoic acid.

  11. OxymaPure/DIC: An Efficient Reagent for the Synthesis of a Novel Series of 4-[2-(2-Acetylaminophenyl-2-oxo-acetylamino] Benzoyl Amino Acid Ester Derivatives

    Directory of Open Access Journals (Sweden)

    Ayman El-Faham

    2013-11-01

    Full Text Available OxymaPure (ethyl 2-cyano-2-(hydroxyiminoacetate was tested as an additive for use in the carbodiimide (DIC approach for the synthesis of a novel series of α-ketoamide derivatives (4-[2-(2-acetylaminophenyl-2-oxo-acetylamino]benzoyl amino acid ester derivatives. OxymaPure showed clear superiority to HOBt/DIC or carbodiimide alone in terms of purity and yield. The title compounds were synthesized via the ring opening of N-acylisatin. First, N-acetylisatin was reacted with 4-aminobenzoic acid under conventional heating as well as microwave irradiation to afford 4-(2-(2-acetamidophenyl-2-oxoacetamidobenzoic acid. This α-ketoamide was coupled to different amino acid esters using OxymaPure/DIC as a coupling reagent to afford 4-[2-(2-acetylaminophenyl-2-oxo-acetylamino]benzoyl amino acid ester derivatives in excellent yield and purity. The synthesized compounds were characterized using FT-IR, NMR, and elemental analysis.

  12. Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans.

    Science.gov (United States)

    Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

    2016-05-15

    Mannose-6-phosphate (M-6-P) glycan analysis is important for quality control of therapeutic enzymes for lysosomal storage diseases. Here, we found that the analysis of glycans containing two M-6-Ps was highly affected by the hydrophilicity of the elution solvent used in high-performance liquid chromatography (HPLC). In addition, the performances of three fluorescent tags--2-aminobenzoic acid (2-AA), 2-aminobenzamide (2-AB), and 3-(acetyl-amino)-6-aminoacridine (AA-Ac)--were compared with each other for M-6-P glycan analysis using HPLC and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The best performance for analyzing M-6-P glycans was shown by 2-AA labeling in both analyses. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Studies on the preparation of labelled compounds for γ scintigraphy use

    International Nuclear Information System (INIS)

    Kim, Jae Rok; Awh, Ok Doo; Park, Kyung Bae; Han, Kwang Hee; Park, Woong Woo

    1990-02-01

    To develop Tc-99m labelling kits of hepatobiliary agents such as IOTIDA and IODIDA, the raw materials were synthesized and the conditions for labelling were optimized. Similar experiments were also conducted for I-131 MIBG of diagnostic use and for stannous MDP, the typical in-vivo labelling agent for RBC. The synthesis yield of IOTIDA and IODIDA were 42 % and 50 %, respectively from the starting materials 2,3,6-trimethylaniline and 2,6-diethylaniline. It has been confirmed that Tc-99m labelling yield of IDA compounds were almost quantitative under optimized conditions and they were excreted mostly through hepatobiliary track. MIBG were synthesized 62 % yield from m-iodobenzylaminehydrochloride and labelled with I-131 almost quantitatively (>98 %). It has been confirmed that p-aminobenzoic acid is an effrective antioxidant for the Tc-99m-MDP. (author)

  14. Hydrogen bonding assemblies in host guest complexes with 18-crown-6

    Science.gov (United States)

    Fonari, M. S.; Simonov, Yu. A.; Kravtsov, V. Ch.; Lipkowski, J.; Ganin, E. V.; Yavolovskii, A. A.

    2003-02-01

    Recent X-ray crystal structural data for two novel 1:2 host-guest complexes of 18-crown-6 with neutral organic molecules, thiaamide hydrazide of 2-aminobenzoic acid and thiaamide hydrazide of 4-amino-1,2,5-thiadiazole-3-carbonic acid are reported. The supramolecular structures of these two and five relative complexes are discussed from the point of view of participation of donor groups in coordination with the crown ether, and donor and acceptor groups in the self-assembly of the guest molecules. Guest molecules have incorporated amine and hydrazine moieties as proton donors and carbonyl oxygen and sulfur (in thiadiazole and in thiaamine moieties) as proton acceptors. The guest-guest interactions appeared to be crucial in the final architecture.

  15. Luminescent hybrid films obtained by covalent grafting of terbium complex to silica network

    International Nuclear Information System (INIS)

    Liu Fengyi; Fu Lianshe; Wang Jun; Liu Ze; Li Huanrong; Zhang Hongjie

    2002-01-01

    Luminescent hybrid thin films consisting of terbium complex covalently bonded to a silica-based network have been obtained in situ via a sol-gel approach. A new monomer, N-(4-benzoic acid-yl), N'-(propyltriethoxysilyl)urea (PABI), has been synthesized by grafting isocyanatopropyltriethoxysilane (ICPTES) to p-aminobenzoic acid and characterized by 1 H NMR, IR and MS. The monomer acts as a ligand for Tb 3+ ion and as a sol-gel precursor. Band emission from Tb 3+ ion due to an efficient ligand-to-metal energy transfer was observed by UV excitation. The decay curves of Tb 3+ in the hybrid films were measured. The energy difference between the triplet state energy of PABI and the 5 D 4 level of Tb 3+ ion falls in the exciting range to sensitize Tb 3+ ion fluorescence

  16. Sunlight suppressing rejection of 280- to 320-nm UV-radiation-induced skin tumors in mice

    International Nuclear Information System (INIS)

    Morison, W.L.; Kelley, S.P.

    1985-01-01

    Repeated exposure of female C3H/HeNCR- mice to sunlight prevented the normal immunologic rejection of a UV-induced tumor. This systemic immunologic alteration was transferred to syngeneic lethally X-irradiated animals with lymphoid cells from mice exposed to sunlight. The lymphoid cells also were able to suppress the capacity of lymphoid cells from normal animals to reject a UV-induced tumor. The 295- to 320-nm wave band appeared to be responsible for this immunosuppressive effect of sunlight because suppression was prevented by filtration of the radiation through Mylar and by application of a sunscreen containing para-aminobenzoic acid. These observations may have importance in understanding the pathogenesis of sunlight-induced skin cancer in humans

  17. Separation of three water-soluble vitamins by poly(dimethylsiloxane) microchannel electrophoresis with electrochemical detection.

    Science.gov (United States)

    Li, Xiang-Yun; Zhang, Qian-Li; Lian, Hong-Zhen; Xu, Jing-Juan; Chen, Hong-Yuan

    2007-09-01

    A method for rapid separation and sensitive determination of three water-soluble vitamins, pyridoxine, ascorbic acid (VC), and p-aminobenzoic acid (PABA) has been developed by PDMS microchannel electrophoresis integrated with amperometric detection. After treatment of the microchip with oxygen plasma, the peak shapes of the three analytes were essentially improved. Pyridoxine, VC, and PABA were well separated within only 80 s in a running buffer of 20 mM borate solution (pH 8.5). Good linearity was obtained within the concentration range of 2-200 microM for the three water-soluble vitamins. The detection limits were 1.0 microM for pyridoxine and VC, and 1.5 microM for PABA. The proposed method has been successfully applied to real human urine sample, without solid phase extraction, with recoveries of 80-122% for the three water-soluble vitamins.

  18. Simultaneous and accurate determination of water- and fat-soluble vitamins in multivitamin tablets by using an RP-HPLC method

    Directory of Open Access Journals (Sweden)

    Semahat Kucukkolbasi

    2013-01-01

    Full Text Available In the present study, a reversed-phase high-performance liquid chromatographic (RP-HPLC procedure was developed and validated for the simultaneous determination of seven water-soluble vitamins (thiamine, riboflavin, niacin, cyanocobalamin, ascorbic acid, folic acid, and p-aminobenzoic acid and four fat-soluble vitamins (retinol acetate, cholecalciferol, α-tocopherol, and phytonadione in multivitamin tablets. The linearity of the method was excellent (R² > 0.999 over the concentration range of 10 - 500 ng mL-1. The statistical evaluation of the method was carried out by performing the intra- and inter-day precision. The accuracy of the method was tested by measuring the average recovery; values ranged between 87.4% and 98.5% and were acceptable quantitative results that corresponded with the label claims.

  19. Inhibition of Long Chain Fatty Acyl-CoA Synthetase (ACSL) and Ischemia Reperfusion Injury

    Science.gov (United States)

    Prior, Allan M.; Zhang, Man; Blakeman, Nina; Datta, Palika; Pham, Hung; Young, Lindon H.; Weis, Margaret T.; Hua, Duy H.

    2014-01-01

    Various triacsin C analogs, containing different alkenyl chains and carboxylic acid bioisoteres including 4-aminobenzoic acid, isothiazolidine dioxide, hydroxylamine, hydroxytriazene, and oxadiazolidine dione, were synthesized and their inhibitions of long chain fatty acyl-CoA synthetase (ACSL) were examined. Two methods, a cell-based assay of ACSL activity and an in situ [14C]-palmitate incorporation into extractable lipids were used to study the inhibition. Using an in vivo leukocyte recruitment inhibition protocol, the translocation of one or more cell adhesion molecules from the cytoplasm to the plasma membrane on either the endothelium or leukocyte or both was inhibited by inhibitors 1, 9, and triacsin C. The results suggest that inhibition of ACSL may attenuate the vascular inflammatory component associated with ischemia reperfusion injury and lead to a decrease of infarct expansion. PMID:24480468

  20. Paramagnetic metal complexes as potential relaxation agents for NMR imaging

    International Nuclear Information System (INIS)

    Coroiu, Ilioara; Demco, D. E.; Darabont, Al.; Bogdan, M.

    1997-01-01

    The development of nuclear magnetic resonance (NMR) imaging technique as a clinical diagnostic modality has prompted the need for a new class of pharmaceuticals. These drugs must be administered to a patient in order to enhance the image contrast between the normal and diseased tissue and/or indicate the status of organ function or blood flow. Paramagnetic compounds are presently undergoing extensive evaluation as contrast agents in magnetic resonance imaging (MRI). These agents increase contrast in MRI by differentially localizing in tissue where they increase the relaxation rates of nearby water protons. The longitudinal R 1 and transverse R 2 relaxivities were measured as a function of molar concentrations for some new paramagnetic complexes like the following: dysprosium, erbium and gadolinium citrates, gadolinium methylene diphosphonate, dysprosium and gadolinium iminodiacetate, manganese para-aminobenzoate and copper nicotinate. The available theoretical approaches for quantitative understanding are presented. (authors)

  1. Bioreporter pseudomonas fluorescens HK44 immobilized in a silica matrix

    Directory of Open Access Journals (Sweden)

    Trogl J.

    2003-01-01

    Full Text Available The bioluminescent bioreporter Pseudomonas fluorescens HK44, the whole cell bacterial biosensor that responds to naphthalene and its metabolites via the production of visible light, was immobilized into a silica matrix by the sol-gel technique. The bioluminescence intensities were measured in the maximum of the bioluminescence band at X = 500 nm. The immobilized cells (>105 cells per g silica matrix produced light after induction by salicylate (cone. > 10 g/l, naphthalene and aminobenzoic acid. The bioluminescence intensities induced by 2,3-dihydroxynaphthalene 3-hydroxybenzoic acid and 4-hydroxybenzoic acid were comparable to a negative control. The cells in the silica layers on glass slides produced light in response to the presence of an inductor at least 8 months after immobilization, and >50 induction cycles. The results showed that these test slides could be used as assays for the multiple determination of water pollution.

  2. Chemical design of pH-sensitive nanovalves on the outer surface of mesoporous silicas for controlled storage and release of aromatic amino acid

    International Nuclear Information System (INIS)

    Roik, N.V.; Belyakova, L.A.

    2014-01-01

    Mesoporous silicas with hexagonally arranged pore channels were synthesized in water–ethanol-ammonia solution using cetyltrimethylammonium bromide as template. Directed modification of silica surface with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups was realized by postsynthetic activation of halogenoalkylsilicas, which have surface uniformly or selectively distributed 3-chloropropyl groups, with 2-aminodiphenylamine in the liquid phase. Chemical composition of silica materials was estimated by IR spectroscopy and chemical analysis of the surface products of reactions. Characteristics of porous structure of MCM-41-type silicas were determined from X-ray and low-temperature nitrogen ad-desorption measurements. Release ability of synthesized silica carriers was established on encapsulation of 4-aminobenzoic acid in pore channels and subsequent delivery at pH=6.86 and pH=1.00. It was found that N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups block pore entrances at neutral pH preventing 4-aminobenzoic acid release. At pH=1.00 repulsion of positively charged surface aromatic amino groups localized near pore orifices provides unhindered liberation of aromatic amino acid from mesoporous channels. - Graphical abstract: Blocking of pores with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups at pH=6.86 for storage of ABA and opening of pore entrances at pH=1.00 for unhindered ABA liberation. - Highlights: • Modification of MCM-41 with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups. • Study of release ability of synthesized silica carriers in relation to amino acid. • Controlled blocking and opening of pores by amino groups at pH change were performed. • Retention of amino acid at pH=6.86 and its liberation at pH=1.00 was proved

  3. Study of antioxidant, anti-protease and anti-urease potential of schiff bases of acetophenone with different amines

    International Nuclear Information System (INIS)

    Ahmed, D.; Mir, H.

    2014-01-01

    Seven acetophenone-derived Schiff bases were synthesized with different amines including 2-aminobenzoic acid (HL1), 4-aminobenzoic acid (HL2), 2-naphthylamine (HL3), phenylhydrazine (HL4), 1,2-ethanediamine (HL5), 1,2-diaminobenzene (HL6) and 1,4-diaminobenzene (HL7), and were subjected to various assays including FRAP (ferric reducing antioxidant power), DPPH (1,1-diphenyl-2-picrylhydrazyl), phosphomolybdate, reducing power, and lipid peroxidation inhibition. They were also evaluated for protease and urease inhibitory activities. Based on the results, structure-activity relationship (SAR) was determined. Only two bases, HL1 and HL4, exhibited antioxidant or free radical scavenging activity in DPPH assay. HL4 was most potent (IC50 15 micro g/mL), while HL1 was only slightly active. As HL4 was the only base with hydrogen bonded to nitrogen, most probably it involves hydrogen transfer (HT) mechanism. All the bases exhibited a range of antioxidant activity in assays involving electron transfer (ET). In the reducing power assay, HL5, HL6 and HL7 showed considerable potential while in FRAP assay, HL7 was most active followed by HL3. In phosphomolybdate assay, HL6 had the highest potency followed by HL7, while HL4 and HL3 also displayed good activity. All the bases showed moderate to high lipid peroxidation inhibitory activity. HL7 exhibited highest protease inhibitory activity (EC50 43.9 mu g/mL) followed by HL6 (EC/sub 50/ 52 mu g/mL). HL4 and HL5 did not show protease inhibitory activity at all. HL2 was most potent in inhibiting urease activity (EC50 29.91 mu g/mL). HL5 and HL6 showed moderate activity. The study showed how variation in structures of Schiff bases alters their antioxidant and anti-enzymatic activities. (author)

  4. A fluorescence-based method for cyanate analysis in ethanol/water media: correlation between cyanate presence and ethyl carbamate formation in sugar cane spirit.

    Science.gov (United States)

    Ohe, Thiago Hideyuki Kobe; da Silva, Alexandre Ataide; Rocha, Thaís da Silva; de Godoy, Flávio Schutzer; Franco, Douglas Wagner

    2014-10-01

    Based on the fluorescence properties of 2,4-(1H,3H)-quinazolinedione, a product of the reaction between cyanate and 2-aminobenzoic acid, a simple, sensitive, selective, and reproducible method for the cyanate analysis in aqueous ethanolic media is proposed. In this method, λ(exc) and λ(em) are 310 and 410 nm, respectively, and the limits of detection and quantification are 2.2 × 10(-7) and 6.7 × 10(-7) mol/L, respectively. Under optimal conditions (pH = 4.5, 40% ethanol), a concentration of 5.0 × 10(-6) mol/L cyanate can be determined in a single measurement, at a 95% level of confidence, with an uncertainty of ± 0.13 × 10(-6) mol/L. Cyanide, thiocyanate, chloride, nitrate, and sulfate ions, as well as urea and urethane in concentrations 1 × 10(3) higher than that of cyanate do not interfere with the measurement. The methodology was applied to cyanate analyses in the different fractions of the sugarcane distillate and the data strongly suggest a correlation between the presence of urea in wine, and the cyanate and ethyl carbamate concentrations in the spirit. Based on the fluorescence properties of the reaction product between cyanate and 2-aminobenzoic acid, a method for assaying cyanate was devised. This procedure applied to the sugarcane distillate showed for the first time a correlation between cyanate presence and ethyl carbamate (EC) formation in the different fractions of the product. Therefore, the proposed methodology can be used to predict in freshly distillate sugar cane spirits the potential total concentration of EC to be formed. Therefore, these data could be used to advise about the necessity of implementing a procedure to reduce spirit EC concentration before the product reaches the market. © 2014 Institute of Food Technologists®

  5. Characterization of inhibitory effects of the potential therapeutic inhibitors, benzoic acid and pyridine derivatives, on the monophenolase and diphenolase activities of tyrosinase.

    Science.gov (United States)

    Gheibi, Nematollah; Taherkhani, Negar; Ahmadi, Abolfazl; Haghbeen, Kamahldin; Ilghari, Dariush

    2015-02-01

    Involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. In the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-amino benzoic acid, 4-amino benzoic acid, nicotinic acid, and picolinic acid on the monophenolase and diphenolase activities of the mushroom tyrosinase, and then MTT assay was exploited to evaluate their toxicity on the melanoma cells. Kinetic analysis revealed that nicotinic acid and picolinic acid competitively restricted the monophenolase activity with inhibition constants (Ki) of 1.21 mM and 1.97 mM and the diphenolase activity with Kis of 2.4 mM and 2.93 mM, respectively. 2-aminobenzoic acid and 4-aminobenzoic acid inhibited the monophenolase activity in a non-competitive fashion with Kis of 5.15 µM and 3.8 µM and the diphenolase activity with Kis of 4.72 µM and 20 µM, respectively. Our cell-based data revealed that only the pyridine derivatives imposed cytotoxicity in melanoma cells. Importantly, the concentrations of the inhibitors leading to 50% decrease in the cell density (IC50) were comparable to those causing 50% drop in the enzyme activity, implying that the observed cytotoxicity is highly likely due to the tyrosinase inhibition. Moreover, our cell-based data exhibited that the pyridine derivatives acted as anti-proliferative agents, perhaps inducing cytotoxicity in the melanoma cells through inhibition of the tyrosinase activities.

  6. Characterization of inhibitory effects of the potential therapeutic inhibitors, benzoic acid and pyridine derivatives, on the monophenolase and diphenolase activities of tyrosinase

    Directory of Open Access Journals (Sweden)

    Nematollah Gheibi

    2015-02-01

    Full Text Available Objective(s:Involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. Materials and Methods: In the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-amino benzoic acid, 4-amino benzoic acid, nicotinic acid, and picolinic acid on the monophenolase and diphenolase activities of the mushroom tyrosinase, and then MTT assay was exploited to evaluate their toxicity on the melanoma cells. Results: Kinetic analysis revealed that nicotinic acid and picolinic acid competitively restricted the monophenolase activity with inhibition constants (Ki of 1.21 mM and 1.97 mM and the diphenolase activity with Kis of 2.4 mM and 2.93 mM, respectively. 2-aminobenzoic acid and 4-aminobenzoic acid inhibited the monophenolase activity in a non-competitive fashion with Kis of 5.15 µM and 3.8 µM and the diphenolase activity with Kis of 4.72 µM and 20 µM, respectively. Conclusion: Our cell-based data revealed that only the pyridine derivatives imposed cytotoxicity in melanoma cells. Importantly, the concentrations of the inhibitors leading to 50% decrease in the cell density (IC50 werecomparable to those causing 50% drop in the enzyme activity, implying that the observed cytotoxicity is highly likely due to the tyrosinase inhibition. Moreover, our cell-based data exhibited that the pyridine derivatives acted as anti-proliferative agents, perhaps inducing cytotoxicity in the melanoma cells through inhibition of the tyrosinase activities.

  7. Characterization and purification of polyphenol oxidase from artichoke (Cynara scolymus L.).

    Science.gov (United States)

    Dogan, Serap; Turan, Yusuf; Ertürk, Hatibe; Arslan, Oktay

    2005-02-09

    In this study, the polyphenol oxidase (PPO) of artichoke (Cynara scolymus L.) was first purified by a combination of (NH(4))(2)SO(4) precipitation, dialysis, and a Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity column. At the end of purification, 43-fold purification was achieved. The purified enzyme migrated as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Polyacrylamide gel electrophoresis indicated that PPO had a 57 kDa molecular mass. Second, the contents of total phenolic and protein of artichoke head extracts were determined. The total phenolic content of artichoke head was determined spectrophotometrically according to the Folin-Ciocalteu procedure and was found to be 425 mg 100 g(-1) on a fresh weight basis. Protein content was determined according to Bradford method. Third, the effects of substrate specificity, pH, temperature, and heat inactivation were investigated on the activity of PPO purified from artichoke. The enzyme showed activity to 4-methylcatechol, pyrogallol, catechol, and L-dopa. No activity was detected toward L-tyrosine, resorsinol, and p-cresol. According to V(max)/K(m) values, 4-methylcatechol (1393 EU min(-1) mM(-1)) was the best substrate, followed by pyrogallol (1220 EU min(-1) mM(-1)), catechol (697 EU min(-1) mM(-1)), and L-dopa (102 EU min(-1) mM(-1)). The optimum pH values for PPO were 5.0, 8.0, and 7.0 using 4-methylcatechol, pyrogallol, and catechol as substrate, respectively. It was found that optimum temperatures were dependent on the substrates studied. The enzyme activity decreased due to heat denaturation of the enzyme with increasing temperature and inactivation time for 4-methylcatechol and pyrogallol substrates. However, all inactivation experiments for catechol showed that the activity of artichoke PPO increased with mild heating, reached a maximum, and then decreased with time. Finally, inhibition of artichoke PPO was investigated with inhibitors such as L-cysteine, EDTA, ascorbic

  8. Investigation of supramolecular synthons and structural characterisation of aminopyridine-carboxylic acid derivatives.

    Science.gov (United States)

    Hemamalini, Madhukar; Loh, Wan-Sin; Quah, Ching Kheng; Fun, Hoong-Kun

    2014-01-01

    Co-crystal is a structurally homogeneous crystalline material that contains two or more neutral building blocks that are present in definite stoichiometric amounts. The main advantage of co-crystals is their ability to generate a variety of solid forms of a drug that have distinct physicochemical properties from the solid co-crystal components. In the present investigation, five co-crystals containing 2-amino-6-chloropyridine (AMPY) moiety were synthesized and characterized. The crystal structure of 2-amino-6-chloropyridine (AMPY) (I), and the robustness of pyridine-acid supramolecular synthon were discussed in four stoichiometry co-crystals of AMPY…BA (II), AMPY…2ABA (III), AMPY…3CLBA (IV) and AMPY…4NBA (V). The abbreviated designations used are benzoic acid (BA), 2-aminobenzoic acid (2ABA), 3-chlorobenzoic acid (3CLBA) and 4-nitrobenzoic acid (4NBA). All the crystalline materials have been characterized by (1)HNMR, (13)CNMR, IR, photoluminescence, TEM analysis and X-ray diffraction. The supramolecular assembly of each co-crystal is analyzed and discussed. Extensive N---H · · · N/N---H · · · O/O---H · · · N hydrogen bonds are found in (I-V), featuring different supramolecular synthons. In the crystal structure, for compound (I), the 2-amino-6-chloropyridine molecules are linked together into centrosymmetric dimers by hydrogen bonds to form homosynthon, whereas for compounds (II-V), the carboxylic group of the respective acids (benzoic acid, 2-aminobenzoic acid, 3-chlorobenzoic acid and 4-nitrobenzoic acid) interacts with pyridine molecule in a linear fashion through a pair of N---H · · · O and O---H · · · N hydrogen bonds, generating cyclic hydrogen-bonded motifs with the graph-set notation [Formula: see text] , to form heterosynthon. In compound (II), another intermolecular N---H · · · O hydrogen bonds further link these heterosynthons into zig-zag chains. Whereas in compounds (IV) and (V

  9. Folate Biofortification in Hydroponically Cultivated Spinach by the Addition of Phenylalanine.

    Science.gov (United States)

    Watanabe, Sho; Ohtani, Yuta; Tatsukami, Yohei; Aoki, Wataru; Amemiya, Takashi; Sukekiyo, Yasunori; Kubokawa, Seiichi; Ueda, Mitsuyoshi

    2017-06-14

    Folate is an important vitamin mainly ingested from vegetables, and folate deficiency causes various health problems. Recently, several studies demonstrated folate biofortification in plants or food crops by metabolic engineering through genetic modifications. However, the production and sales of genetically modified foods are under strict regulation. Here, we developed a new approach to achieve folate biofortification in spinach (Spinacia oleracea) without genetic modification. We hydroponically cultivated spinach with the addition of three candidate compounds expected to fortify folate. As a result of liquid chromatography tandem mass spectrometry analysis, we found that the addition of phenylalanine increased the folate content up to 2.0-fold (306 μg in 100 g of fresh spinach), representing 76.5% of the recommended daily allowance for adults. By measuring the intermediates of folate biosynthesis, we revealed that phenylalanine activated folate biosynthesis in spinach by increasing the levels of pteridine and p-aminobenzoic acid. Our approach is a promising and practical approach to cultivate nutrient-enriched vegetables.

  10. Actions of four organic acids in radix isatidis on endotoxin-neutralization investigated by kinetic turbidimetric assay.

    Science.gov (United States)

    Ma, Li; He, Ying-jun; Li, You; Gong, Mu-xin

    2012-06-01

    To investigate anti-endotoxin action of four OAs reacted with endotoxin by the LAL assay with KTA. Using a incubating kinetic tube reader and kinetic turbidimetric assay (KTA), the concentration-response time curve of endotoxin reacted with limulus amebocyte lysate (LAL) at 37 degrees C were obtained and the action of four organic acids (OAs) on it were investigated. The four OAs were benzoic acid, salicylic acid, syringic acid and 2-amino-benzoic acid from Radix isatidis. Meanwhile, the temperature variation caused by endotoxin with the four OAs was studied by the rabbit pyrogen test (RPT). It was showed that a low concentration (1 mg/mL) of the four OAs had a little effect of anti-endotoxin, and when the concentrations of the four OAs were 30 mg/mL, the endotoxin was neutralized completely. The relationships between the concentrations of endotoxin and the OAs were all linear with correlation coefficients of greater than 0.9995, indicating that the four OAs all had strong anti-endotoxin action, while syringic acid had the strongest action among the four OAs with IC50 of 12.84 mg/mL. The investigations of KTA agreed well with the results obtained by means of RPT.

  11. Biofuel cells based on direct enzyme-electrode contacts using PQQ-dependent glucose dehydrogenase/bilirubin oxidase and modified carbon nanotube materials.

    Science.gov (United States)

    Scherbahn, V; Putze, M T; Dietzel, B; Heinlein, T; Schneider, J J; Lisdat, F

    2014-11-15

    Two types of carbon nanotube electrodes (1) buckypaper (BP) and (2) vertically aligned carbon nanotubes (vaCNT) have been used for elaboration of glucose/O2 enzymatic fuel cells exploiting direct electron transfer. For the anode pyrroloquinoline quinone dependent glucose dehydrogenase ((PQQ)GDH) has been immobilized on [poly(3-aminobenzoic acid-co-2-methoxyaniline-5-sulfonic acid), PABMSA]-modified electrodes. For the cathode bilirubin oxidase (BOD) has been immobilized on PQQ-modified electrodes. PABMSA and PQQ act as promoter for enzyme bioelectrocatalysis. The voltammetric characterization of each electrode shows current densities in the range of 0.7-1.3 mA/cm(2). The BP-based fuel cell exhibits maximal power density of about 107 µW/cm(2) (at 490 mV). The vaCNT-based fuel cell achieves a maximal power density of 122 µW/cm(2) (at 540 mV). Even after three days and several runs of load a power density over 110 µW/cm(2) is retained with the second system (10mM glucose). Due to a better power exhibition and an enhanced stability of the vaCNT-based fuel cells they have been studied in human serum samples and a maximal power density of 41 µW/cm(2) (390 mV) can be achieved. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. 4-N-pyridin-2-yl-benzamide nanotubes compatible with mouse stem cell and oral delivery in Drosophila

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Jhillu S; Das, Pragna P; Bag, Indira; Krishnan, Anita; Jagannadh, Bulusu; Mohapatra, Debendra K; Bhadra, Manika Pal [Division of Organic Chemistry-I, Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007 (India); Lavanya, Madugula P; Bhadra, Utpal [Functional Genomics and Gene Silencing Group, Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007 (India)

    2010-04-16

    p-aminobenzoic acid (PABA), a structural moiety of many commercial drugs, is self-assembled with linker alkyl side chains to form tubular nanostructures. The tubes exhibited fluorescence either intrinsic or from fluorescent molecules embedded in the wall during self-assembly. Uptake and inter-cellular delivery of the conjugated nanotubes in human cancer cells and in mouse embryonic stem cells were demonstrated by fluorescence imaging and flow cytometry. Biocompatibility, cytotoxicity and clearance were monitored both ex vivo in mouse multipotent embryonic stem cells and in vivo in adult Drosophila. Accumulation of nanotubes had no adverse effects and abnormalities on stem cell morphology and proliferation rate. A distinct distribution of two separate nanotubes in various internal organs of Drosophila interprets that accumulation of nanomaterials might be interdependent on the side chain modifications and physiological settings of cell or tissue types. Unlike carbon nanomaterials, exposure of PABA nanotubes does not produce any hazards including locomotion defects and mortality of adult flies. Despite differential uptake and clearance from multiple live tissues, the use of self-assembled nanotubes can add new dimensions and scope to the development of dual-purpose oral carriers for the fulfilment of many biological promises.

  13. A Titanium–Organic Framework as an Exemplar of Combining the Chemistry of Metal– and Covalent–Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ha L.; Gándara, Felipe; Furukawa, Hiroyasu; Doan, Tan L. H.; Cordova, Kyle E.; Yaghi, Omar M.

    2016-04-06

    A crystalline material with a two-dimensional structure, termed metal–organic framework-901 (MOF-901), was prepared using a strategy that combines the chemistry of MOFs and covalent–organic frameworks (COFs). This strategy involves in situ generation of an amine-functionalized titanium oxo cluster, Ti6O6(OCH3)6(AB)6 (AB = 4-aminobenzoate), which was linked with benzene-1,4-dialdehyde using imine condensation reactions, typical of COFs. The crystal structure of MOF-901 is composed of hexagonal porous layers that are likely stacked in staggered conformation (hxl topology). This MOF represents the first example of combining metal cluster chemistry with dynamic organic covalent bond formation to give a new crystalline, extended framework of titanium metal, which is rarely used in MOFs. The incorporation of Ti(IV) units made MOF-901 useful in the photocatalyzed polymerization of methyl methacrylate (MMA). The resulting polyMMA product was obtained with a high-number-average molar mass (26 850 g mol–1) and low polydispersity index (1.6), which in many respects are better than those achieved by the commercially available photocatalyst (P-25 TiO2). Additionally, the catalyst can be isolated, reused, and recycled with no loss in performance.

  14. Enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody as a new tool to detect Sudan dyes and Para red

    International Nuclear Information System (INIS)

    Ju Chunmei; Tang Yong; Fan Huiying; Chen Jinding

    2008-01-01

    To set up an immunoassay-based method to detect Sudan dyes and Para red, we generated a monoclonal antibody (Mab) using a specially designed carboxyl derivative of Sudan I (CSD I) as the immunogen. CSD I was synthesized by azocoupling reaction using 2-naphthol and diazotised 4-aminobenzoic acid. The antibody was obtained from a hybridoma, which was derived from the fusion of the mouse myeloma SP2/0 cells and the splenocytes from the mice immunized with the CSD I-bovine serum albumin (BSA) conjugate. In addition, we showed that the Mab was highly specific for Sudan I, III and Para red. The limit of detection was approximately 0.01 ng mL -1 in phosphate-buffered saline (PBS) buffer and 0.5 ng g -1 in chilli tomato sauce. The recoveries of Sudan I, III and Para red for the chilli tomato sauce were from 84% to 99% and coefficients of variation were from 14.9% to 33.3%. Thus, the enzyme-linked immunosorbent assay (ELISA) method is a rapid and high throughput screening tool to detect Sudan dyes and Para red in food products

  15. Enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody as a new tool to detect Sudan dyes and Para red

    Energy Technology Data Exchange (ETDEWEB)

    Ju Chunmei [College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642 (China); Tang Yong [Center of Antibody Engineering, Department of Bioengineering, Jinan University, Guangzhou 510632 (China); Fan Huiying [College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642 (China); Chen Jinding [College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642 (China)], E-mail: jdchen@scau.edu.cn

    2008-07-28

    To set up an immunoassay-based method to detect Sudan dyes and Para red, we generated a monoclonal antibody (Mab) using a specially designed carboxyl derivative of Sudan I (CSD I) as the immunogen. CSD I was synthesized by azocoupling reaction using 2-naphthol and diazotised 4-aminobenzoic acid. The antibody was obtained from a hybridoma, which was derived from the fusion of the mouse myeloma SP2/0 cells and the splenocytes from the mice immunized with the CSD I-bovine serum albumin (BSA) conjugate. In addition, we showed that the Mab was highly specific for Sudan I, III and Para red. The limit of detection was approximately 0.01 ng mL{sup -1} in phosphate-buffered saline (PBS) buffer and 0.5 ng g{sup -1} in chilli tomato sauce. The recoveries of Sudan I, III and Para red for the chilli tomato sauce were from 84% to 99% and coefficients of variation were from 14.9% to 33.3%. Thus, the enzyme-linked immunosorbent assay (ELISA) method is a rapid and high throughput screening tool to detect Sudan dyes and Para red in food products.

  16. Performances of carbon-based screen-printed electrodes modified by diazonium salts with various carboxylic functions for trace metal sensors

    International Nuclear Information System (INIS)

    Bouden, Sarra; Bellakhal, Nizar; Chausse, Annie; Vautrin-Ul, Christine

    2014-01-01

    The electrochemically induced functionalization of carbon-based screen-printed-electrodes (SPEs) by phenyl groups, having one or two carboxylic functions, was achieved by reduction of in situ generated diazonium salts in aqueous media. The corresponding diazonium cations of 4-aminobenzoic acid, 4-aminophthalic acid, 3-(4-aminophenyl) propionic acid, 3-(4-aminophenyl)-2-propenoic acid and 5-aminoisophthalic acid were generated in situ with sodium nitrite in aqueous H_2SO_4. The electrochemical detection of Pb(II) with the grafted SPEs was investigated using Pb(II) 5 * 10"-"8 M solutions. The performances of the grafted SPEs were found to be dependent on the number of carboxylic groups, on their position on the phenyl ring, on the olefinic or the aliphatic character of the chain bearing the carboxylic group. The performances of mono-4-carboxyphenyl and 3,5-dicarboxyphenyl grafted SPEs for Cd(II) and Cu(II) trace detection were tested and compared. (authors)

  17. Electrochemical immunosensor for ethinylestradiol using diazonium salt grafting onto silver nanoparticles-silica-graphene oxide hybrids.

    Science.gov (United States)

    Cincotto, Fernando H; Martínez-García, Gonzalo; Yáñez-Sedeño, Paloma; Canevari, Thiago C; Machado, S A S; Pingarrón, José M

    2016-01-15

    This work describes the preparation of an electrochemical immunosensor for ethinylestradiol (EE2) based on grafting of diazonium salt of 4-aminobenzoic acid onto a glassy carbon electrode modified with silver nanoparticles/SiO2/graphene oxide hybrid followed by covalent binding of anti-ethinylestradiol (anti-EE2) to activated carboxyl groups. A competitive immunoassay was developed for the determination of the hormone using peroxidase-labeled ethinylestradiol (HRP-EE2) and measurement of the amperometric response at -200mV in the presence of hydroquinone (HQ) as redox mediator. The calibration curve for EE2 exhibited a linear range between 0.1 and 50ng/mL (r(2)=0.996), with a detection limit of 65pg/mL. Interference studies with other hormones related with EE2 revealed the practical specificity of the developed method for the analyte. A good reproducibility, with RSD=4.5% (n=10) was also observed. The operating stability of a single bioelectrode modified with anti-EE2 was maintained at least for 15 days when it was stored at 4°C under humid conditions between measurements. The developed immunosensor was applied to the analysis of spiked urine with good results. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Synthesis of new low band gap dyes with BF{sub 2}-azopyrrole complex and their use for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mikroyannidis, John A. [Chemical Technology Laboratory, Department of Chemistry, University of Patras, GR-26500 Patras (Greece); Roy, M.S. [Defence Laboratory, Jodhpur (Raj.) (India); Sharma, G.D. [Physics Department, Molecular Electronic and Optoelectronic Device Laboratory, JNV University, Jodhpur (Raj.) 342005 (India); Jaipur Engineering College, Kukas, Jaipur (Raj.) (India)

    2010-08-15

    The diazonium salt derived from 4-aminobenzoic acid, 4-aminophenol or 2-aminophenol reacted with half equivalent of pyrrole to afford symmetrical 2,5-bisazopyrroles. They reacted subsequently with boron trifluoride in the presence of triethylamine to afford the corresponding BF{sub 2}-azopyrrole complexes D1, D2 and D3 respectively. They were soluble and stable in nonprotic solvents such as chloroform, dichloromethane and tetrahydrofuran but unstable in protic solvents such as ethanol. Their absorption spectra were broad with optical band gap of 1.49-1.70 eV. Among these dyes D2 displayed the broader absorption spectrum with low band gap E{sub g}{sup opt} of 1.49 eV. We have utilized these complexes as photosensitizers for quasi solid state dye-sensitized solar cells (DSSCs) and achieved power conversion efficiency in the range of 4.0-6.0%. We have also found that the co-adsorption of citric acid hindered the formation of dye aggregates and might improve the electron injection efficiency leading to an enhancement in short circuit photocurrent. This work suggests that metal-free dyes based on BF{sub 2}-azopyrrole complex are promising candidates for improvement of the DSSC performance. (author)

  19. Dielectric Properties of Azo Polymers: Effect of the Push-Pull Azo Chromophores

    Directory of Open Access Journals (Sweden)

    Xuan Zhang

    2018-01-01

    Full Text Available The relationship between the structure and the dielectric properties of the azo polymers was studied. Four azo polymers were synthesized through the azo-coupling reaction between the same precursor (PAZ and diazonium salts of 4-aminobenzoic acid ethyl ester, 4-aminobenzonitrile, 4-nitroaniline, and 2-amino-5-nitrothiazole, respectively. The precursor and azo polymers were characterized by 1H NMR, FT-IR, UV-vis, GPC, and DSC. The dielectric constant and dielectric loss of the samples were measured in the frequency range of 100 Hz–200 kHz. Due to the existence of the azo chromophores, the dielectric constant of the azo polymers increases compared with that of the precursor. In addition, the dielectric constant of the azo polymers increases with the increase of the polarity of the azo chromophores. A random copolymer (PAZ-NT-PAZ composed of the azo polymer PAZ-NT and the precursor PAZ was also prepared to investigate the content of the azo chromophores on the dielectric properties of the azo polymers. It showed that the dielectric constant increases with the increase of the azo chromophores. The results show that the dielectric constant of this kind of azo polymers can be controlled by changing the structures and contents of azo chromophores during the preparation process.

  20. Fabrication of an electrochemical sensor based on computationally designed molecularly imprinted polymer for the determination of mesalamine in real samples

    Energy Technology Data Exchange (ETDEWEB)

    Torkashvand, M. [Department of Analytical Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Gholivand, M.B., E-mail: mbgholivand@yahoo.com [Department of Analytical Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Taherkhani, F. [Department of Physical Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-10-01

    A novel electrochemical sensor based on mesalamine molecularly imprinted polymer (MIP) film on a glassy carbon electrode was fabricated. Density functional theory (DFT) in gas and solution phases was developed to study the intermolecular interactions in the pre-polymerization mixture and to find the suitable functional monomers in MIP preparation. On the basis of computational results, o-phenylenediamine (OP), gallic acid (GA) and p-aminobenzoic acid (ABA) were selected as functional monomers. The MIP film was cast on glassy carbon electrode by electropolymerization of solution containing ternary monomers and then followed by Ag dendrites (AgDs) with nanobranch deposition. The surface feature of the modified electrode (AgDs/MIP/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under the optimal experimental conditions, the peak current was proportional to the concentration of mesalamine ranging from 0.05 to 100 μM, with the detection limit of 0.015 μM. The proposed sensor was applied successfully for mesalamine determination in real samples. - Highlights: • The determination of MES using AgDs/MIP/GCE is reported for the first time. • The computer assisted design of terpolymer MIPs was used to screen monomers. • Theoretical results of DFT approach were in agreement with experimental results. • The sensor displayed a high selectivity for template in the presence of interferes. • The developed sensor has been applied to determine mesalamine in real samples.

  1. Content of Phenolic Compounds and Antioxidant Capacity in Fruits of Apricot Genotypes

    Directory of Open Access Journals (Sweden)

    Helena Skutkova

    2010-09-01

    Full Text Available Research on natural compounds is increasingly focused on their effects on human health. In this study, we were interested in the evaluation of nutritional value expressed as content of total phenolic compounds and antioxidant capacity of new apricot (Prunus armeniaca L. genotypes resistant against Plum pox virus (PPV cultivated on Department of Fruit Growing of Mendel University in Brno. Fruits of twenty one apricot genotypes were collected at the onset of consumption ripeness. Antioxidant capacities of the genotypes were determined spectrometrically using DPPH• (1,1-diphenyl-2-picryl-hydrazyl free radicals scavenging test, TEAC (Trolox Equivalent Antioxidant Capacity, and FRAP (Ferric Reducing Antioxidant Powermethods. The highest antioxidant capacities were determined in the genotypes LE-3228 and LE-2527, the lowest ones in the LE-985 and LE-994 genotypes. Moreover, close correlation (r = 0.964 was determined between the TEAC and DPPH assays. Based on the antioxidant capacity and total polyphenols content, a clump analysis dendrogram of the monitored apricot genotypes was constructed. In addition, we optimized high performance liquid chromatography coupled with tandem electrochemical and spectrometric detection and determined phenolic profile consisting of the following fifteen phenolic compounds: gallic acid, 4-aminobenzoic acid, chlorogenic acid, ferulic acid, caffeic acid, procatechin, salicylic acid, p-coumaric acid, the flavonols quercetin and quercitrin, the flavonol glycoside rutin, resveratrol, vanillin, and the isomers epicatechin, (–- and (+- catechin.

  2. De Novo Synthesis of Benzenoid Compounds by the Yeast Hanseniaspora vineae Increases the Flavor Diversity of Wines.

    Science.gov (United States)

    Martin, Valentina; Giorello, Facundo; Fariña, Laura; Minteguiaga, Manuel; Salzman, Valentina; Boido, Eduardo; Aguilar, Pablo S; Gaggero, Carina; Dellacassa, Eduardo; Mas, Albert; Carrau, Francisco

    2016-06-08

    Benzyl alcohol and other benzenoid-derived metabolites of particular importance in plants confer floral and fruity flavors to wines. Among the volatile aroma components in Vitis vinifera grape varieties, benzyl alcohol is present in its free and glycosylated forms. These compounds are considered to originate from grapes only and not from fermentative processes. We have found increased levels of benzyl alcohol in red Tannat wine compared to that in grape juice, suggesting de novo formation of this metabolite during vinification. In this work, we show that benzyl alcohol, benzaldehyde, p-hydroxybenzaldehyde, and p-hydroxybenzyl alcohol are synthesized de novo in the absence of grape-derived precursors by Hanseniaspora vineae. Levels of benzyl alcohol produced by 11 different H. vineae strains were 20-200 times higher than those measured in fermentations with Saccharomyces cerevisiae strains. These results show that H. vineae contributes to flavor diversity by increasing grape variety aroma concentration in a chemically defined medium. Feeding experiments with phenylalanine, tryptophan, tyrosine, p-aminobenzoic acid, and ammonium in an artificial medium were tested to evaluate the effect of these compounds either as precursors or as potential pathway regulators for the formation of benzenoid-derived aromas. Genomic analysis shows that the phenylalanine ammonia-lyase (PAL) and tyrosine ammonia lyase (TAL) pathways, used by plants to generate benzyl alcohols from aromatic amino acids, are absent in the H. vineae genome. Consequently, alternative pathways derived from chorismate with mandelate as an intermediate are discussed.

  3. Photoallergic contact dermatitis. Results of photopatch testing in New York, 1985 to 1990.

    Science.gov (United States)

    DeLeo, V A; Suarez, S M; Maso, M J

    1992-11-01

    Over a 6-year period, 187 patients with a history of photosensitivity were photopatch tested using standard techniques. Seventy-six patients were male and 111 were female. Most patients were white (151 patients). Two thirds of the patients were between the ages of 31 and 60 years. Testing revealed a total of 63 positive reactions: 14 plain contact, 41 photocontact, and eight combined contact and photocontact in 37 (20%) patients. Careful history taking resulted in a diagnosis of clinically relevant photoallergic contact dermatitis in 54% of these 37 patients or 11% (20) of the total tested. Ten of the relevant responses were due to fragrance ingredients (musk ambrette and 6-methylcoumarin); 18 were due to sunscreen agents (nine to p-aminobenzoic acid and esters, nine to oxybenzone). The fragrance reactions occurred in the early years of the study (1985, 1986, and 1987) while the sunscreen agents accounted for all but two of the 14 positive reactions in the last 3 years of the study (1988, 1989, and 1990). These data suggest that the incidence of photoallergy due to fragrances is declining, while reactions to sunscreen agents, in particular oxybenzone, are increasing. This trend may reflect an altered use pattern by the general population for products containing these chemicals.

  4. Enzymatic Synthesis of Lignin-Based Concrete Dispersing Agents.

    Science.gov (United States)

    Jankowska, Dagmara; Heck, Tobias; Schubert, Mark; Yerlikaya, Alpaslan; Weymuth, Christophe; Rentsch, Daniel; Schober, Irene; Richter, Michael

    2018-03-15

    Lignin is the most abundant aromatic biopolymer, functioning as an integral component of woody materials. In its unmodified form it shows limited water solubility and is relatively unreactive, so biotechnological lignin valorisation for high-performance applications is greatly underexploited. Lignin can be obtained from the pulp and paper industry as a by-product. To expand its application, a new synthesis route to new dispersing agents for use as concrete additives was developed. The route is based on lignin functionalisation by enzymatic transformation. Screening of lignin-modifying systems resulted in functionalised lignin polymers with improved solubility in aqueous systems. Through grafting of sulfanilic acid or p-aminobenzoic acid by fungal laccases, lignin became soluble in water at pH≤4 or pH≤7, respectively. Products were analysed and evaluated in miniaturised application tests in cement paste and mortar. Their dispersing properties match the performance criteria of commercially available lignosulfonates. The study provides examples of new perspectives for the use of lignin. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Metabolic Engineering of the Shikimate Pathway for Production of Aromatics and Derived Compounds—Present and Future Strain Construction Strategies

    Directory of Open Access Journals (Sweden)

    Nils J. H. Averesch

    2018-03-01

    Full Text Available The aromatic nature of shikimate pathway intermediates gives rise to a wealth of potential bio-replacements for commonly fossil fuel-derived aromatics, as well as naturally produced secondary metabolites. Through metabolic engineering, the abundance of certain intermediates may be increased, while draining flux from other branches off the pathway. Often targets for genetic engineering lie beyond the shikimate pathway, altering flux deep in central metabolism. This has been extensively used to develop microbial production systems for a variety of compounds valuable in chemical industry, including aromatic and non-aromatic acids like muconic acid, para-hydroxybenzoic acid, and para-coumaric acid, as well as aminobenzoic acids and aromatic α-amino acids. Further, many natural products and secondary metabolites that are valuable in food- and pharma-industry are formed outgoing from shikimate pathway intermediates. (Reconstruction of such routes has been shown by de novo production of resveratrol, reticuline, opioids, and vanillin. In this review, strain construction strategies are compared across organisms and put into perspective with requirements by industry for commercial viability. Focus is put on enhancing flux to and through shikimate pathway, and engineering strategies are assessed in order to provide a guideline for future optimizations.

  6. Noninvasive investigation of exocrine pancreatic function: Feasibility of cine dynamic MRCP with a spatially selective inversion-recovery pulse.

    Science.gov (United States)

    Yasokawa, Kazuya; Ito, Katsuyoshi; Tamada, Tsutomu; Yamamoto, Akira; Hayashida, Minoru; Tanimoto, Daigo; Higaki, Atsushi; Noda, Yasufumi; Kido, Ayumu

    2015-11-01

    To investigate the feasibility of noncontrast-enhanced cine dynamic magnetic resonance cholangiopancreatography (MRCP) with a spatially selective inversion-recovery (IR) pulse for evaluating exocrine pancreatic function in comparison with the N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) test as a pancreatic exocrine function test. Twenty subjects with or without chronic pancreatitis were included. MRCP with a spatially selective IR pulse was repeated every 15 seconds for 5 minutes to acquire a total of 20 images (cine-dynamic MRCP). The median and mean frequency of the observation (the number of times) and the moving distance (mean secretion grading scores) of pancreatic juice inflow on cine-dynamic MRCP were compared with a BT-PABA test. The urinary PABA excretion rate (%) had significant positive correlations with both the mean secretion grade (r = 0.66, P = 0.002) and frequency of secretory inflow (r = 0.62, P = 0.004) in cine dynamic MRCP. Both the mean frequency of observations of pancreatic secretory inflow (1.4 ± 1.6 times vs. 14.3 ± 4.2 times, P Cine dynamic MRCP with a spatially selective IR pulse may have potential for estimating the pancreatic exocrine function noninvasively as a substitute for the BT-PABA test. © 2015 Wiley Periodicals, Inc.

  7. Production and characterization of a camelid single domain antibody-urease enzyme conjugate for the treatment of cancer.

    Science.gov (United States)

    Tian, Baomin; Wong, Wah Yau; Hegmann, Elda; Gaspar, Kim; Kumar, Praveen; Chao, Heman

    2015-06-17

    A novel immunoconjugate (L-DOS47) was developed and characterized as a therapeutic agent for tumors expressing CEACAM6. The single domain antibody AFAIKL2, which targets CEACAM6, was expressed in the Escherichia coli BL21 (DE3) pT7-7 system. High purity urease (HPU) was extracted and purified from Jack bean meal. AFAIKL2 was activated using N-succinimidyl [4-iodoacetyl] aminobenzoate (SIAB) as the cross-linker and then conjugated to urease. The activation and conjugation reactions were controlled by altering pH. Under these conditions, the material ratio achieved conjugation ratios of 8-11 antibodies per urease molecule, the residual free urease content was practically negligible (95%) L-DOS47 conjugate was produced using only ultradiafiltration to remove unreacted antibody and hydrolyzed cross-linker. L-DOS47 was characterized by a panel of analytical techniques including SEC, IEC, Western blot, ELISA, and LC-MS(E) peptide mapping. As the antibody-urease conjugate ratio increased, a higher binding signal was observed. The specificity and cytotoxicity of L-DOS47 was confirmed by screening in four cell lines (BxPC-3, A549, MCF7, and CEACAM6-transfected H23). BxPC-3, a CEACAM6-expressing cell line was found to be most susceptible to L-DOS47. L-DOS47 is being investigated as a potential therapeutic agent in human phase I clinical studies for nonsmall cell lung cancer.

  8. Combined mutagenesis of Rhodosporidium toruloides for improved production of carotenoids and lipids.

    Science.gov (United States)

    Zhang, Chaolei; Shen, Hongwei; Zhang, Xibin; Yu, Xue; Wang, Han; Xiao, Shan; Wang, Jihui; Zhao, Zongbao K

    2016-10-01

    To improve production of lipids and carotenoids by the oleaginous yeast Rhodosporidium toruloides by screening mutant strains. Upon physical mutagenesis of the haploid strain R. toruloides np11 with an atmospheric and room temperature plasma method followed by chemical mutagenesis with nitrosoguanidine, a mutant strain, R. toruloides XR-2, formed dark-red colonies on a screening plate. When cultivated in nitrogen-limited media, XR-2 cells grew slower but accumulated 0.23 g lipids/g cell dry wt and 0.75 mg carotenoids/g CDW. To improve its production capacity, different amino acids and vitamins were supplemented. p-Aminobenzoic acid and tryptophan had beneficial effects on cell growth. When cultivated in nitrogen-limited media in the presence of selected vitamins, XR-2 accumulated 0.41 g lipids/g CDW and 0.69 mg carotenoids/g CDW. A mutant R. toruloides strain with improved production profiles for lipids and carotenoids was obtained, indicating its potential to use combined mutagenesis for a more productive phenotype.

  9. Excessive folate synthesis limits lifespan in the C. elegans: E. coli aging model

    Directory of Open Access Journals (Sweden)

    Virk Bhupinder

    2012-07-01

    Full Text Available Abstract Background Gut microbes influence animal health and thus, are potential targets for interventions that slow aging. Live E. coli provides the nematode worm Caenorhabditis elegans with vital micronutrients, such as folates that cannot be synthesized by animals. However, the microbe also limits C. elegans lifespan. Understanding these interactions may shed light on how intestinal microbes influence mammalian aging. Results Serendipitously, we isolated an E. coli mutant that slows C. elegans aging. We identified the disrupted gene to be aroD, which is required to synthesize aromatic compounds in the microbe. Adding back aromatic compounds to the media revealed that the increased C. elegans lifespan was caused by decreased availability of para-aminobenzoic acid, a precursor to folate. Consistent with this result, inhibition of folate synthesis by sulfamethoxazole, a sulfonamide, led to a dose-dependent increase in C. elegans lifespan. As expected, these treatments caused a decrease in bacterial and worm folate levels, as measured by mass spectrometry of intact folates. The folate cycle is essential for cellular biosynthesis. However, bacterial proliferation and C. elegans growth and reproduction were unaffected under the conditions that increased lifespan. Conclusions In this animal:microbe system, folates are in excess of that required for biosynthesis. This study suggests that microbial folate synthesis is a pharmacologically accessible target to slow animal aging without detrimental effects.

  10. Utilization of Boron Compounds for the Modification of Suberoyl Anilide Hydroxamic Acid as Inhibitor of Histone Deacetylase Class II Homo sapiens

    Science.gov (United States)

    Bakri, Ridla; Parikesit, Arli Aditya; Satriyanto, Cipta Prio; Kerami, Djati; Tambunan, Usman Sumo Friend

    2014-01-01

    Histone deacetylase (HDAC) has a critical function in regulating gene expression. The inhibition of HDAC has developed as an interesting anticancer research area that targets biological processes such as cell cycle, apoptosis, and cell differentiation. In this study, an HDAC inhibitor that is available commercially, suberoyl anilide hydroxamic acid (SAHA), has been modified to improve its efficacy and reduce the side effects of the compound. Hydrophobic cap and zinc-binding group of these compounds were substituted with boron-based compounds, whereas the linker region was substituted with p-aminobenzoic acid. The molecular docking analysis resulted in 8 ligands with ΔG binding value more negative than the standards, SAHA and trichostatin A (TSA). That ligands were analyzed based on the nature of QSAR, pharmacological properties, and ADME-Tox. It is conducted to obtain a potent inhibitor of HDAC class II Homo sapiens. The screening process result gave one best ligand, Nova2 (513246-99-6), which was then further studied by molecular dynamics simulations. PMID:25214833

  11. Acemetacin cocrystal structures by powder X-ray diffraction

    Science.gov (United States)

    Bolla, Geetha

    2017-01-01

    Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), p-aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R 3 2(9)R 2 2(8)R 3 2(9) with three different syn amides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I) or syn (type II). ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O⋯H, N⋯H, Cl⋯H and C⋯H interactions. The physicochemical properties of these cocrystals are under study. PMID:28512568

  12. Novel furosemide cocrystals and selection of high solubility drug forms.

    Science.gov (United States)

    Goud, N Rajesh; Gangavaram, Swarupa; Suresh, Kuthuru; Pal, Sharmistha; Manjunatha, Sulur G; Nambiar, Sudhir; Nangia, Ashwini

    2012-02-01

    Furosemide was screened in cocrystallization experiments with pharmaceutically acceptable coformer molecules to discover cocrystals of improved physicochemical properties, that is high solubility and good stability. Eight novel equimolar cocrystals of furosemide were obtained by liquid-assisted grinding with (i) caffeine, (ii) urea, (iii) p-aminobenzoic acid, (iv) acetamide, (v) nicotinamide, (vi) isonicotinamide, (vii) adenine, and (viii) cytosine. The product crystalline phases were characterized by powder x-ray diffraction, differential scanning calorimetry, infrared, Raman, near IR, and (13) C solid-state NMR spectroscopy. Furosemide-caffeine was characterized as a neutral cocrystal and furosemide-cytosine an ionic salt by single crystal x-ray diffraction. The stability of furosemide-caffeine, furosemide-adenine, and furosemide-cytosine was comparable to the reference drug in 10% ethanol-water slurry; there was no evidence of dissociation of the cocrystal to furosemide for up to 48 h. The other five cocrystals transformed to furosemide within 24 h. The solubility order for the stable forms is furosemide-cytosine > furosemide-adenine > furosemide-caffeine, and their solubilities are approximately 11-, 7-, and 6-fold higher than furosemide. The dissolution rates of furosemide cocrystals were about two times faster than the pure drug. Three novel furosemide compounds of higher solubility and good phase stability were identified in a solid form screen. Copyright © 2011 Wiley Periodicals, Inc.

  13. Acemetacin cocrystal structures by powder X-ray diffraction

    Directory of Open Access Journals (Sweden)

    Geetha Bolla

    2017-05-01

    Full Text Available Cocrystals of acemetacin drug (ACM with nicotinamide (NAM, p-aminobenzoic acid (PABA, valerolactam (VLM and 2-pyridone (2HP were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R32(9R22(8R32(9 with three different syn amides (VLM, 2HP and caprolactam. The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I or syn (type II. ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O...H, N...H, Cl...H and C...H interactions. The physicochemical properties of these cocrystals are under study.

  14. Novel Isoniazid cocrystals with aromatic carboxylic acids: Crystal engineering, spectroscopy and thermochemical investigations

    Science.gov (United States)

    Diniz, Luan F.; Souza, Matheus S.; Carvalho, Paulo S.; da Silva, Cecilia C. P.; D'Vries, Richard F.; Ellena, Javier

    2018-02-01

    Four novel cocrystals of the anti-tuberculosis drug Isoniazid (INH), including two polymorphs, with the aromatic carboxylic acids p-nitrobenzoic (PNBA), p-cyanobenzoic (PCNBA) and p-aminobenzoic (PABA) were rationally designed and synthesized by solvent evaporation. Aiming to explore the possible supramolecular synthons of this API, these cocrystals were fully characterized by X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR) and thermal (TGA, DSC, HSM) techniques. The cocrystal formation was found to be mainly driven by the synthons formed by the pyridine and hydrazide moieties. In both INH-PABA polymorphs, the COOH acid groups are H-bonded to pyridine and hydrazide groups giving rise to the acid⋯pyridine and acid⋯hydrazide heterosynthons. In INH-PNBA and INH-PCNBA cocrystals these acid groups are only related to the pyridine moiety. In addition to the structural study, supramolecular and Hirshfeld surface analysis were also performed based on the structural data. The cocrystals were identified from the FT-IR spectra and their thermal behaviors were studied by a combination of DSC, TGA and HSM techniques.

  15. Ab initio random structure searching of organic molecular solids: assessment and validation against experimental data† †Electronic supplementary information (ESI) available: Results of similarity analysis between the 11 structures of lowest energy obtained in the AIRSS calculations and the reported structures of form III and form IV of m-ABA; unit cell parameters and volumes for all structures considered; comparison of 2θ values derived from the unit cell parameters of different structural models representing form III of m-ABA; Le Bail fitting of the experimental powder XRD pattern of form IV of m-ABA recorded at 70 K using, as the initial structural model, the reported crystal structure following geometry optimization; table of calculated (GIPAW) absolute isotropic NMR shieldings; simulated powder XRD data for the considered structures after precise geometry optimization; experimental 1H MAS NMR spectra of forms III and IV. (pdf) The calculated and experimental data for this study are provided as a supporting dataset from WRAP, the Warwick Research Archive Portal at http://wrap.warwick.ac.uk/91884. See DOI: 10.1039/c7cp04186a

    Science.gov (United States)

    Zilka, Miri; Dudenko, Dmytro V.; Hughes, Colan E.; Williams, P. Andrew; Sturniolo, Simone; Franks, W. Trent; Pickard, Chris J.

    2017-01-01

    This paper explores the capability of using the DFT-D ab initio random structure searching (AIRSS) method to generate crystal structures of organic molecular materials, focusing on a system (m-aminobenzoic acid; m-ABA) that is known from experimental studies to exhibit abundant polymorphism. Within the structural constraints selected for the AIRSS calculations (specifically, centrosymmetric structures with Z = 4 for zwitterionic m-ABA molecules), the method is shown to successfully generate the two known polymorphs of m-ABA (form III and form IV) that have these structural features. We highlight various issues that are encountered in comparing crystal structures generated by AIRSS to experimental powder X-ray diffraction (XRD) data and solid-state magic-angle spinning (MAS) NMR data, demonstrating successful fitting for some of the lowest energy structures from the AIRSS calculations against experimental low-temperature powder XRD data for known polymorphs of m-ABA, and showing that comparison of computed and experimental solid-state NMR parameters allows different hydrogen-bonding motifs to be discriminated. PMID:28944393

  16. Gold nanostar-enhanced surface plasmon resonance biosensor based on carboxyl-functionalized graphene oxide

    International Nuclear Information System (INIS)

    Wu, Qiong; Sun, Ying; Ma, Pinyi; Zhang, Di; Li, Shuo; Wang, Xinghua; Song, Daqian

    2016-01-01

    A new high-sensitivity surface plasmon resonance (SPR) biosensor based on biofunctional gold nanostars (AuNSs) and carboxyl-functionalized graphene oxide (cGO) sheets was described. Compared with spherical gold nanoparticles (AuNPs), the anisotropic structure of AuNSs, which concentrates the electric charge density on its sharp tips, could enhance the local electromagnetic field and the electronic coupling effect significantly. cGO was obtained by a diazonium reaction of graphene oxide (GO) with 4-aminobenzoic acid. Compared with GO, cGO could immobilize more antibodies due to the abundant carboxylic groups on its surface. Testing results show that there are fairly large improvements in the analytical performance of the SPR biosensor using cGO/AuNSs-antigen conjugate, and the detection limit of the proposed biosensor is 0.0375 μg mL"−"1, which is 32 times lower than that of graphene oxide-based biosensor. - Highlights: • A sensitive and versatile SPR biosensor was constructed for detection of pig IgG. • Biofunctional gold nanostars were used to amplify the response signals. • The strategy employed carboxyl-functionalized graphene oxide as biosensing substrate. • The detection limit of the proposed biosensor is 32 times lower than that of graphene oxide-based biosensor.

  17. A review on cholinesterase inhibitors for Alzheimer's disease.

    Science.gov (United States)

    Anand, Preet; Singh, Baldev

    2013-04-01

    Alzheimer's disease (AD), a progressive neurodegenerative disorder, is characterized by the deficits in the cholinergic system and deposition of beta amyloid (Aβ) in the form of neurofibrillary tangles and amyloid plaques. Since the cholinergic system plays an important role in the regulation of learning and memory processes, it has been targetted for the design of anti-Alzheimer's drugs. Cholinesterase inhibitors enhance cholinergic transmission directly by inhibiting the enzyme acetylcholinesterase (AChE) which hydrolyses acetylcholine. Furthermore, it has been also demonstrated that both acetylcholinesterase and butrylcholinesterase (BuChE) play an important role in Aβ-aggregation during the early stages of senile plaque formation. Therefore, AChE and BuChE inhibition have been documented as critical targets for the effective management of AD by an increase in the availability of acetylcholine in the brain regions and decrease in the Aβ deposition. This review discusses the different classes of cholinesterase inhibitors including tacrine, donepezil, rivastigmine, galantamine, xanthostigmine, para-aminobenzoic acid, coumarin, flavonoid, and pyrrolo-isoxazole analogues developed for the treatment of AD.

  18. Occurrence of organic UV filters and metabolites in lebranche mullet (Mugil liza) from Brazil.

    Science.gov (United States)

    Molins-Delgado, Daniel; Muñoz, Ramón; Nogueira, Sylvia; Alonso, Mariana B; Torres, João Paulo; Malm, Olaf; Ziolli, Roberta Lourenço; Hauser-Davis, Rachel Ann; Eljarrat, Ethel; Barceló, Damià; Díaz-Cruz, M Silvia

    2018-03-15

    UV filters (UV-Fs) constitute a heterogeneous group of chemicals used as protection against the effects of UV radiation, widely used in all sort of goods and ubiquitous in the environment. The presence of these chemicals in fish is a matter of concern, because many UV-Fs display hormonal activity. In this study, muscle, gills, and liver from 11 Mugil liza individuals from the highly urbanized Guanabara Bay (Rio de Janeiro, Brazil) were analysed in order to detect eight UV-Fs and metabolites (4-dihydroxybenzophenone [BP1] (2-hydroxy-4-methoxybenzophenone [BP3], 4-methylbenzylidiene camphor [4MBC], ethylhexyl methoxycinnamate [EHMC], ethylhexyl dimethyl p-aminobenzoic acid [ODPABA], octocrylene [OC], 4-hydroxybenzophenone [4HB], and 4,4'-dihydroxybenzophenone [4DHB]) using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results showed that both target UV-Fs and metabolites were ubiquitous in the analysed tissues. Lower concentrations were observed in muscle and gills (3.07-31.6ngg -1 dry weight (dw)), whereas in liver significant amounts of metabolites (5.47-451ngg -1 dw) were present. With the concentrations determined in the fish, an estimation of the daily intake revealed that consumption of muscle in the diet represent from 0.3 to 15.2ng UV-Fs (kg body weight -1 ) d -1 , higher than those reported in fish for selected persistent organic pollutants (POPs). Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Simultaneous Liquid Chromatographic Determination of 10 Ultra-Violet Filters in Sunscreens.

    Science.gov (United States)

    Wharton, Mary; Geary, Michael; O'Connor, Niamh; Curtin, Laura; Ketcher, Krystal

    2015-09-01

    A rapid HPLC method was developed for the simultaneous determination of 10 UV filters found in sunscreen. The following UV filters were analyzed in this method; 2-phenylbenzimidazole-5-sulfonic acid, benzophenone-3, isoamyl p-methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, ethylhexyl dimethyl 4-aminobenzoic acid, ethylhexyl methoxycinnamate, butyl methoxydibenzoylmethane, ethylhexyl salicylate and homosalate. The method was developed on two columns; a Thermo Hypersil C18 BDS, 3 µm column (4.6 × 100 mm) and a Chromolith RP-18e Monolithic column (4.6 × 100 mm). The same mobile phase of ethanol and 1% acetic acid (70:30, v/v) was employed for both columns. The separation of the 10 UV filters was carried out successfully on both columns; the optimal resolution was obtained on the Thermo Scientific Hypersil column in a time frame of 7 min. An isocratic elution utilizing ethanol and acetic acid (70:30, v/v) at a temperature of 35°C was employed. The method was applied to a number of commercial samples of sunscreen and lotions and was validated according to International Conference on Harmonisation guidelines for selectivity, linearity, accuracy, precision and robustness. A comparison of the performances of both columns was also carried out. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Simultaneous determination of some ultraviolet-absorbing chemicals in sunscreen cosmetics using a high-performance liquid chromatography method.

    Science.gov (United States)

    Liu, T; Wu, D

    2011-10-01

    A method of gradient elution high-performance liquid chromatography (HPLC) for simultaneous determination of 11 different ultraviolet-absorbing chemicals of phenylbenzlmldazole sulphonic acid, 4-aminobenzoic acid, benzophenone-4, benzophenone-3, isoamyl p-methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, ethylhexyl methoxycinnamate, homosalate, ethylhexyl salicylate, methylene bis-benzotriazolyl tetramethylbutyl phenol was developed for the application to sunscreen cosmetic products. In this study, an Agilent SB-C18 analytical column (250 × 4.6 mm, 5 μm) was utilized and methanol, tetrahydrofuran and perchloric acid aqueous solution (0.2 mL HClO(4) + 300 mL H(2)O) were used for gradient elution at a total flow rate of 1.0 mL min(-1). The optimum conditions for 11 different ultraviolet-absorbing chemicals analyses were investigated. All calibration curves showed good linear regression with UV detection (311 nm) within test ranges. The correlation coefficients were better than 0.999 in all cases. The assay was simple, selective, convenient and reproducible and is suitable for the determination of ultraviolet-absorbing chemicals in commercial sunscreen cosmetic products. The use frequency of 11 different ultraviolet absorbents in 100 sunscreen cosmetics was investigated and statistically analysed. The ultraviolet absorbent of maximum use frequency was ethylhexyl methoxycinnamate. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  1. Environmental occurrence and ecological risk assessment of organic UV filters in marine organisms from Hong Kong coastal waters.

    Science.gov (United States)

    Sang, Ziye; Leung, Kelvin Sze-Yin

    2016-10-01

    Organic UV filters, now considered to be emerging contaminants in aquatic ecosystems, are being intensively tracked in environmental waters worldwide. However, their environmental fate and impact of these contaminants on marine organisms remains largely unknown, especially in Asia. This work elucidates the occurrence and the ecological risks of seven UV filters detected in farmed fish, wild mussels and some other wild organisms collected from local mariculture farms in Hong Kong. For all of the organisms, ethylhexyl methoxycinnamate (EHMC) and octyl dimethyl p-aminobenzoic acid (OD-PABA) were the predominant contaminants with the highest concentrations up to 51.3 and 24.1ng/g (dw), respectively; lower levels were found for benzophenone-8 (BP-8), octocrylene (OC) and benzophenone-3 (BP-3) from

  2. Statistical process control of cocrystallization processes: A comparison between OPLS and PLS.

    Science.gov (United States)

    Silva, Ana F T; Sarraguça, Mafalda Cruz; Ribeiro, Paulo R; Santos, Adenilson O; De Beer, Thomas; Lopes, João Almeida

    2017-03-30

    Orthogonal partial least squares regression (OPLS) is being increasingly adopted as an alternative to partial least squares (PLS) regression due to the better generalization that can be achieved. Particularly in multivariate batch statistical process control (BSPC), the use of OPLS for estimating nominal trajectories is advantageous. In OPLS, the nominal process trajectories are expected to be captured in a single predictive principal component while uncorrelated variations are filtered out to orthogonal principal components. In theory, OPLS will yield a better estimation of the Hotelling's T 2 statistic and corresponding control limits thus lowering the number of false positives and false negatives when assessing the process disturbances. Although OPLS advantages have been demonstrated in the context of regression, its use on BSPC was seldom reported. This study proposes an OPLS-based approach for BSPC of a cocrystallization process between hydrochlorothiazide and p-aminobenzoic acid monitored on-line with near infrared spectroscopy and compares the fault detection performance with the same approach based on PLS. A series of cocrystallization batches with imposed disturbances were used to test the ability to detect abnormal situations by OPLS and PLS-based BSPC methods. Results demonstrated that OPLS was generally superior in terms of sensibility and specificity in most situations. In some abnormal batches, it was found that the imposed disturbances were only detected with OPLS. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

    Science.gov (United States)

    DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

    2015-05-01

    Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  4. Analysis of fluorescently labeled glycosphingolipid-derived oligosaccharides following ceramide glycanase digestion and anthranilic acid labeling.

    Science.gov (United States)

    Neville, David C A; Coquard, Virginie; Priestman, David A; te Vruchte, Danielle J M; Sillence, Daniel J; Dwek, Raymond A; Platt, Frances M; Butters, Terry D

    2004-08-15

    Interest in cellular glycosphingolipid (GSL) function has necessitated the development of a rapid and sensitive method to both analyze and characterize the full complement of structures present in various cells and tissues. An optimized method to characterize oligosaccharides released from glycosphingolipids following ceramide glycanase digestion has been developed. The procedure uses the fluorescent compound anthranilic acid (2-aminobenzoic acid; 2-AA) to label oligosaccharides prior to analysis using normal-phase high-performance liquid chromatography. The labeling procedure is rapid, selective, and easy to perform and is based on the published method of Anumula and Dhume [Glycobiology 8 (1998) 685], originally used to analyze N-linked oligosaccharides. It is less time consuming than a previously published 2-aminobenzamide labeling method [Anal. Biochem. 298 (2001) 207] for analyzing GSL-derived oligosaccharides, as the fluorescent labeling is performed on the enzyme reaction mixture. The purification of 2-AA-labeled products has been improved to ensure recovery of oligosaccharides containing one to four monosaccharide units, which was not previously possible using the Anumula and Dhume post-derivatization purification procedure. This new approach may also be used to analyze both N- and O-linked oligosaccharides.

  5. Secondary Interactions Arrest the Hemiaminal Intermediate To Invert the Modus Operandi of Schiff Base Reaction: A Route to Benzoxazinones.

    Science.gov (United States)

    Patel, Ketan; Deshmukh, Satej S; Bodkhe, Dnyaneshwar; Mane, Manoj; Vanka, Kumar; Shinde, Dinesh; Rajamohanan, Pattuparambil R; Nandi, Shyamapada; Vaidhyanathan, Ramanathan; Chikkali, Samir H

    2017-04-21

    Discovered by Hugo Schiff, condensation between amine and aldehyde represents one of the most ubiquitous reactions in chemistry. This classical reaction is widely used to manufacture pharmaceuticals and fine chemicals. However, the rapid and reversible formation of Schiff base prohibits formation of alternative products, of which benzoxazinones are an important class. Therefore, manipulating the reactivity of two partners to invert the course of this reaction is an elusive target. Presented here is a synthetic strategy that regulates the sequence of Schiff base reaction via weak secondary interactions. Guided by the computational models, reaction between 2,3,4,5,6-pentafluoro-benzaldehyde with 2-amino-6-methylbenzoic acid revealed quantitative (99%) formation of 5-methyl-2-(perfluorophenyl)-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (15). Electron donating and electron withdrawing ortho-substituents on 2-aminobenzoic acid resulted in the production of benzoxazinones 9-36. The mode of action was tracked using low temperature NMR, UV-vis spectroscopy, and isotopic ( 18 O) labeling experiments. These spectroscopic mechanistic investigations revealed that the hemiaminal intermediate is arrested by the hydrogen-bonding motif to yield benzoxazinone. Thus, the mechanistic investigations and DFT calculations categorically rule out the possibility of in situ imine formation followed by ring-closing, but support instead hydrogen-bond assisted ring-closing to prodrugs. This unprecedented reaction represents an interesting and competitive alternative to metal catalyzed and classical methods of preparing benzoxazinone.

  6. Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

    Science.gov (United States)

    Bhattacharjee, Chira R.; Goswami, Pankaj; Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh

    2011-05-01

    Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] ( n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements ( μeff ˜ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (Δ Ep > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential ( E1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.

  7. Prediction of gradient retention data for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

    Science.gov (United States)

    Vaňková, Nikola; Česla, Petr

    2017-02-17

    In this work, we have investigated the predictive properties of mixed-mode retention model and oligomeric mixed-mode model, taking into account the contribution of monomeric units to the retention, in hydrophilic interaction liquid chromatography. The gradient retention times of native maltooligosaccharides and their fluorescent derivatives were predicted in the oligomeric series with number of monomeric glucose units in the range from two to seven. The maltooligosaccharides were separated on a packed column with carbamoyl-bonded silica stationary phase and 15 gradient profiles with different initial and final mobile phase composition were used with the gradient times 5; 7.5 and 10min. The predicted gradient retention times were compared for calculations based on isocratic retention data and gradient retention data, which provided better accuracy of the results. By comparing two different mobile phase additives, the more accurate retention times were predicted in mobile phases containing ammonium acetate. The acidic derivatives, prepared by reaction of an oligosaccharide with 2-aminobenzoic acid or 8-aminonaphthalene-1,3,6-trisulfonic acid, provided more accurate predictions of the retention data in comparison to native oligosaccharides or their neutral derivatives. The oligomeric mixed-mode model allowed prediction of gradient retention times using only one gradient profile, which significantly speeded-up the method development. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Increase in the penetration of tracer compounds into the rat brain during 2-methyl-4-chlorophenoxyacetic acid (MCPA) intoxication

    International Nuclear Information System (INIS)

    Elo, H.A.; Ylitalo, P.; Kyoettilae, J.; Hervonen, H.

    1982-01-01

    The penetration of different intravenous tracer molecules such as 14 C-labelled 2-methyl-4-chlorophenoxyacetic acid ( 14 C-MCPA), 14 C-p-aminobenzoic acid ( 14 C-PABA), 14 C-sucrose, 14 C-antipyrine and iodinated ( 125 I) human albumin ( 125 I-HA) into the brain and cerebrospinal fluid (CSF) was studied in MCPA-intoxicated and control rats. Toxic subcutaneous doses of sodium salt of MCPA (200-500 mg/kg) increased highly the brain/plasma and CSF/plasma ratios of 14 C-MCPA and 14 C-PABA, as compared to the muscle/plasma ratio. Probenecid (200 mg/kg) did not affect the cerebral MCPA concentration in the intoxicated animals. The tissue/plasma ratios of 14 C-sucrose, 14 C-antipyrine and 125 I-HA were also increased in the brain and CSF of intoxicated animals, but the increases were less pronounced than those of 14 C-MCPA or 14 C-PABA. The results indicate that MCPA intoxication caused a selective damage of the blood-brain barrier in the brain areas studied. (author)

  9. Synthesis, characterization and biocidal activity of new organotin complexes of 2-(3-oxocyclohex-1-enyl)benzoic acid.

    Science.gov (United States)

    Vieira, Flaviana T; de Lima, Geraldo M; Maia, José R da S; Speziali, Nivaldo L; Ardisson, José D; Rodrigues, Leonardo; Correa, Ary; Romero, Oscar B

    2010-03-01

    The reaction of 1,3-cyclohexadione with 2-aminobenzoic acid has produced the 2-(3-oxocyclohex-1-enyl)benzoic acid (HOBz). Subsequent reactions of the ligand with organotin chlorides led to [Me(2)Sn(OBz)O](2) (1), [Bu(2)Sn(OBz)O](2) (2), [Ph(2)Sn(OBz)O](2) (3), [Me(3)Sn(OBz)] (4), [Bu(3)Sn(OBz)] (5) and [Ph(3)Sn(OBz)] (6). All complexes have been fully characterized. In addition the structure of complexes (2) and (4) have been authenticated by X-ray crystallography. The biological activity of all derivatives has been screened against Cryptococcus neoformans and Candida albicans. In addition we have performed toxicological testes employing human kidney cell. The complexes (3), (5) and (6) displayed the best values of inhibition of the fungus growing, superior to ketoconazole. Compound (5) presented promising results in view of the antifungal and cytotoxicity assays. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

  10. Nonreductive chemical release of intact N-glycans for subsequent labeling and analysis by mass spectrometry.

    Science.gov (United States)

    Yuan, Jiangbei; Wang, Chengjian; Sun, Yujiao; Huang, Linjuan; Wang, Zhongfu

    2014-10-01

    A novel strategy is proposed, using cost-saving chemical reactions to generate intact free reducing N-glycans and their fluorescent derivatives from glycoproteins for subsequent analysis. N-Glycans without core α-1,3-linked fucose are released in reducing form by selective hydrolysis of the N-type carbohydrate-peptide bond of glycoproteins under a set of optimized mild alkaline conditions and are comparable to those released by commonly used peptide-N-glycosidase (PNGase) F in terms of yield without any detectable side reaction (peeling or deacetylation). The obtained reducing glycans can be routinely derivatized with 2-aminobenzoic acid (2-AA), 1-phenyl-3-methyl-5-pyrazolone (PMP), and potentially some other fluorescent reagents for comprehensive analysis. Alternatively, the core α-1,3-fucosylated N-glycans are released in mild alkaline medium and derivatized with PMP in situ, and their yields are comparable to those obtained using commonly used PNGase A without conspicuous peeling reaction or any detectable deacetylation. Using this new technique, the N-glycans of a series of purified glycoproteins and complex biological samples were successfully released and analyzed by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS), demonstrating its general applicability to glycomic studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Data for analysis of mannose-6-phosphate glycans labeled with fluorescent tags.

    Science.gov (United States)

    Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

    2016-06-01

    Mannose-6-phosphate (M-6-P) glycan plays an important role in lysosomal targeting of most therapeutic enzymes for treatment of lysosomal storage diseases. This article provides data for the analysis of M-6-P glycans by high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The identities of M-6-P glycan peaks in HPLC profile were confirmed by measuring the masses of the collected peak eluates. The performances of three fluorescent tags (2-aminobenzoic acid [2-AA], 2-aminobenzamide [2-AB], and 3-(acetyl-amino)-6-aminoacridine [AA-Ac]) were compared focusing on the analysis of bi-phosphorylated glycan (containing two M-6-Ps). The bi-phosphorylated glycan analysis is highly affected by the attached fluorescent tag and the hydrophilicity of elution solvent used in HPLC. The data in this article is associated with the research article published in "Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans" (Kang et al., 2016 [1]).

  12. Antibacterial Co(II, Ni(II, Cu(II and Zn(II complexes with biacetyl-derived Schiff bases

    Directory of Open Access Journals (Sweden)

    MUHAMMAD IMRAN

    2010-08-01

    Full Text Available The condensation reactions of biacetyl with ortho-hydroxyaniline and 2-aminobenzoic acid to form bidendate NO donor Schiff bases were studied. The prepared Schiff base ligands were further utilized for the formation of metal chelates having the general formula [ML2(H2O2] where M = Co(II, Ni(II, Cu(II and Zn(II and L = HL1 and HL2. These new compounds were characterized by conductance measurements, magnetic susceptibility measurements, elemental analysis, and IR, 1H-NMR, 13C-NMR and electronic spectroscopy. Both Schiff base ligands were found to have a mono-anionic bidentate nature and octahedral geometry was assigned to all metal complexes. All the complexes contained coordinated water which was lost at 141–160 °C. These compounds were also screened for their in vitro antibacterial activity against four bacterial species, namely: Escherichia coli, Staphylococcus aureus, Salmonella typhi and Bacillus subtilis. The metal complexes were found to have greater antibacterial activity than the uncomplexed Schiff base ligands.

  13. A signal-on electrogenerated chemiluminescent biosensor for lead ion based on DNAzyme

    International Nuclear Information System (INIS)

    Ma Fen; Sun Bo; Qi Honglan; Zhang Hongge; Gao Qiang; Zhang Chengxiao

    2011-01-01

    A highly reproducible and sensitive signal-on electrogenerated chemiluminescence (ECL) biosensor based on the DNAzyme for the determination of lead ion was developed. The ECL biosensor was fabricated by covalently coupling 5'-amino-DNAzyme-tagged with ruthenium bis (2,2'-bipyridine) (2,2'-bipyridine-4,4'-dicarboxylic acid)-ethylenediamine (Ru1-17E') onto the surface of graphite electrode modified with 4-aminobenzoic acid, and then a DNA substrate with a ribonucleotide adenosine hybridized with Ru1-17E' on the electrode. Upon binding of Pb 2+ to the Ru1-17E' to form a complex which catalyzed the cleavage of the DNA substrate, the double-stranded DNA was dissociated and thus led to a high ECL signal. The signal linearly increases with the concentration of Pb 2+ in the range from 5.0 to 80 pM with a detection limit of 1.4 pM and a relative standard derivation of 2.3%. This work demonstrates that using DNAzyme tagged with ruthenium complex as an ECL probe and covalently coupling method for the fabrication of the ECL biosensor with high sensitivity, good stability and significant regeneration ability is promising approach.

  14. 4-N-pyridin-2-yl-benzamide nanotubes compatible with mouse stem cell and oral delivery in Drosophila

    International Nuclear Information System (INIS)

    Yadav, Jhillu S; Das, Pragna P; Bag, Indira; Krishnan, Anita; Jagannadh, Bulusu; Mohapatra, Debendra K; Bhadra, Manika Pal; Lavanya, Madugula P; Bhadra, Utpal

    2010-01-01

    p-aminobenzoic acid (PABA), a structural moiety of many commercial drugs, is self-assembled with linker alkyl side chains to form tubular nanostructures. The tubes exhibited fluorescence either intrinsic or from fluorescent molecules embedded in the wall during self-assembly. Uptake and inter-cellular delivery of the conjugated nanotubes in human cancer cells and in mouse embryonic stem cells were demonstrated by fluorescence imaging and flow cytometry. Biocompatibility, cytotoxicity and clearance were monitored both ex vivo in mouse multipotent embryonic stem cells and in vivo in adult Drosophila. Accumulation of nanotubes had no adverse effects and abnormalities on stem cell morphology and proliferation rate. A distinct distribution of two separate nanotubes in various internal organs of Drosophila interprets that accumulation of nanomaterials might be interdependent on the side chain modifications and physiological settings of cell or tissue types. Unlike carbon nanomaterials, exposure of PABA nanotubes does not produce any hazards including locomotion defects and mortality of adult flies. Despite differential uptake and clearance from multiple live tissues, the use of self-assembled nanotubes can add new dimensions and scope to the development of dual-purpose oral carriers for the fulfilment of many biological promises.

  15. A new method for the quantification of monosaccharides, uronic acids and oligosaccharides in partially hydrolyzed xylans by HPAEC-UV/VIS.

    Science.gov (United States)

    Lorenz, Dominic; Erasmy, Nicole; Akil, Youssef; Saake, Bodo

    2016-04-20

    A new method for the chemical characterization of xylans is presented, to overcome the difficulties in quantification of 4-O-methyl-α-D-glucuronic acid (meGlcA). In this regard, the hydrolysis behavior of xylans from beech and birch wood was investigated to obtain the optimum conditions for hydrolysis, using sulfuric acid. Due to varying linkage strengths and degradation, no general method for complete hydrolysis can be designed. Therefore, partial hydrolysis was applied, yielding monosaccharides and small meGlcA containing oligosaccharides. For a new method by HPAEC-UV/VIS, these samples were reductively aminated by 2-aminobenzoic acid. By quantification of monosaccharides and oligosaccharides, as well as comparison with borate-HPAEC and (13)C NMR-spectroscopy, we revealed that the concentrations meGlcA are significantly underestimated compared to conventional methods. The detected concentrations are 85.4% (beech) and 76.3% (birch) higher with the new procedure. Furthermore, the quantified concentrations of xylose were 9.3% (beech) and 6.5% (birch) higher by considering the unhydrolyzed oligosaccharides as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Electrografting of carboxyphenyl thin layer onto gold for DNA and enzyme immobilization

    International Nuclear Information System (INIS)

    Nowicka, Anna M.; Fau, Michal; Kowalczyk, Agata; Strawski, Marcin; Stojek, Zbigniew

    2014-01-01

    The convenient functionalization of metal surfaces by carboxyphenyl groups in aprotic media is not possible for two reasons. First, carboxy derivatives of diazonium salts are very unstable and, second, the electroreduction product is soluble in the solvent. So, the optimization of the conditions of the electrografting of the metal surfaces by applying aqueous solutions is much needed. Compared to earlier cyclic voltammetry approaches we have shown that the chronoamperometric deposition is more convenient. The constant potential equal to the voltammetric peak potential and the molar ratio 1:1 for the substrates: 4-aminobenzoic acid and NaNO 2 as the diazotization agent, in 0.5 M HCl, appeared to be very satisfying conditions for the deposition of a thin layer of deposit of perpendicularly oriented carboxyphenyl groups at the Au surface and for maximal elimination of the influence of the side-reactions products. Under the determined conditions the immobilization of DNA strands was optimal and the deposited laccase layer was tightly packed and very efficient toward the electroreduction of oxygen. Electrochemical impedance spectroscopy, electrochemical quartz crystal microbalance, cyclic voltammetry, chronocoulometry, atomic force microscopy, contact angle measurements and UV–Vis spectroscopy of the solution were used to characterize the electrografted carboxyphenyl layers and subsequent oligonucleotide and enzyme immobilization process

  17. Spectroscopic characterization of metal complexes of novel Schiff base. Synthesis, thermal and biological activity studies

    Science.gov (United States)

    Omar, M. M.; Mohamed, Gehad G.; Ibrahim, Amr A.

    2009-07-01

    Novel Schiff base (HL) ligand is prepared via condensation of 4-aminoantipyrine and 2-aminobenzoic acid. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA, DrTGA and DTA). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a uninegatively tridentate manner with NNO donor sites of the azomethine N, amino N and deprotonated caroxylic-O. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ΔH*, ΔS* and ΔG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus Pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Shciff base ligand against one or more bacterial species.

  18. Engineering the substrate specificity of the DhbE adenylation domain by yeast cell surface display.

    Science.gov (United States)

    Zhang, Keya; Nelson, Kathryn M; Bhuripanyo, Karan; Grimes, Kimberly D; Zhao, Bo; Aldrich, Courtney C; Yin, Jun

    2013-01-24

    The adenylation (A) domains of nonribosomal peptide synthetases (NRPSs) activate aryl acids or amino acids to launch their transfer through the NRPS assembly line for the biosynthesis of many medicinally important natural products. In order to expand the substrate pool of NRPSs, we developed a method based on yeast cell surface display to engineer the substrate specificities of the A-domains. We acquired A-domain mutants of DhbE that have 11- and 6-fold increases in k(cat)/K(m) with nonnative substrates 3-hydroxybenzoic acid and 2-aminobenzoic acid, respectively and corresponding 3- and 33-fold decreases in k(cat)/K(m) values with the native substrate 2,3-dihydroxybenzoic acid, resulting in a dramatic switch in substrate specificity of up to 200-fold. Our study demonstrates that yeast display can be used as a high throughput selection platform to reprogram the "nonribosomal code" of A-domains. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. An azoreductase, aerobic NADH-dependent flavoprotein discovered from Bacillus sp.: functional expression and enzymatic characterization.

    Science.gov (United States)

    Ooi, Toshihiko; Shibata, Takeshi; Sato, Reiko; Ohno, Hiroaki; Kinoshita, Shinichi; Thuoc, Tran Linh; Taguchi, Seiichi

    2007-05-01

    The gene coding for an azoreductase, designated as an azrA, was cloned by polymerase chain reaction amplification from the genomic DNA of Bacillus sp. strain B29 isolated from soil. The azrA encoded a protein of 208 amino acids with calculated molecular mass of 22,766 Da. The enzyme was heterologously expressed in Escherichia coli with a strong band of 23 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Purified recombinant AzrA was a homodimer with a native molecular mass of 48 kDa containing two molecules of flavin mononucleotide (FMN; oxidized). This activity was oxygen insensitive and was nicotinamide adenine dinucleotide (reduced form; NADH) dependent. Recombinant AzrA exhibited a broad pH stability between 6 and 10 with a temperature optimum of 60-80 degrees C. The enzyme cleaved the model azo compound of methyl red [MR, 4'-(dimethylamino)-azobenzene-2-carboxylic acid] into 2-aminobenzoic acid and N, N'-dimethyl-p-phenylenediamine by ping-pong mechanism. The enzyme was not only able to decolorize MR but also able to decolorize sulfonated azo dyes such as Orange I and Acid Red 88.

  20. Radiation-induced G/sub 2/-arrest is reduced by inhibitors of poly(adenosine diphosphoribose) synthetase

    International Nuclear Information System (INIS)

    Rowley, R.

    1985-01-01

    Experiments are in progress to test whether poly(adenosine diphosphoribose) synthesis is required for the induction of G/sub 2/-arrest in growing mammalian cells following X-irradiation. A variety of poly(ADPR) synthetase inhibitors have been tested to determine: 1) whether addition of an inhibitor to X-irradiated CHO cells reduces G/sub 2/-arrest; 2) whether compounds structurally similar to poly-(ADPR) synthetase inhibitors but inactive against this enzyme affect radiation-induced G/sub 2/-arrest and 3) whether the concentration dependence for poly(ADPR) synthetase inhibition matches that for G/sub 2/-arrest reduction. G/sub 2/-arrest was measured in X-irradiated (1.5 Gy) CHO cells using the mitotic cell selection technique. Poly(ADPR) synthetase activity was measured in permeabilized cells by /sup 3/H-NAD incorporation. The synthetase inhibitors used were 3-aminobenzamide, benzamide, nicotinamide, 4-acetyl pyridine, caffeine and theophylline. The inactive compounds used were 3-aminobenzoic acid, benzoic acid, nicotinic acid, adenine, adenosine and 3'-deoxyadenosine. Inhibitors of poly(ADPR) synthetase reduced G/sub 2/-arrest while related compounds which produced no enzyme inhibition did not. The concentration dependencies for G/sub 2/-arrest reduction and enzyme inhibition were similar only for methyl xanthines. Further analysis awaits the determination of intracellular drug concentrations

  1. Peroxide Activation for Electrophilic Reactivity by the Binuclear Non-heme Iron Enzyme AurF

    International Nuclear Information System (INIS)

    Park, Kiyoung; Li, Ning; Kwak, Yeonju; Srnec, Martin

    2017-01-01

    Binuclear non-heme iron enzymes activate O 2 for diverse chemistries that include oxygenation of organic substrates and hydrogen atom abstraction. This process often involves the formation of peroxo-bridged biferric intermediates, only some of which can perform electrophilic reactions. To elucidate the geometric and electronic structural requirements to activate peroxo reactivity, the active peroxo intermediate in 4-aminobenzoate N-oxygenase (AurF) has been characterized spectroscopically and computationally. A magnetic circular dichroism study of reduced AurF shows that its electronic and geometric structures are poised to react rapidly with O 2 . Nuclear resonance vibrational spectroscopic definition of the peroxo intermediate formed in this reaction shows that the active intermediate has a protonated peroxo bridge. Density functional theory computations on the structure established here show that the protonation activates peroxide for electrophilic/single-electron-transfer reactivity. As a result, this activation of peroxide by protonation is likely also relevant to the reactive peroxo intermediates in other binuclear non-heme iron enzymes.

  2. Biochemical and molecular characterization of an azoreductase from Staphylococcus aureus, a tetrameric NADPH-dependent flavoprotein

    Science.gov (United States)

    Chen, Huizhong; Hopper, Sherryll L.; Cerniglia, Carl E.

    2018-01-01

    Azo dyes are a predominant class of colourants used in tattooing, cosmetics, foods and consumer products. A gene encoding NADPH-flavin azoreductase (Azo1) from the skin bacterium Staphylococcus aureus ATCC 25923 was identified and overexpressed in Escherichia coli. RT-PCR results demonstrated that the azo1 gene was constitutively expressed at the mRNA level in S. aureus. Azo1 was found to be a tetramer with a native molecular mass of 85 kDa containing four non-covalently bound FMN. Azo1 requires NADPH, but not NADH, as an electron donor for its activity. The enzyme was resolved to dimeric apoprotein by removing the flavin prosthetic groups using hydrophobic-interaction chromatography. The dimeric apoprotein was reconstituted on-column and in free stage with FMN, resulting in the formation of a fully functional native-like tetrameric enzyme. The enzyme cleaved the model azo dye 2-[4-(dimethylamino)phenylazo]benzoic acid (Methyl Red) into N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid. The apparent Km values for NADPH and Methyl Red substrates were 0·;074 and 0·057 mM, respectively. The apparent Vmax was 0·4 µM min−1 (mg protein)−1. Azo1 was also able to metabolize Orange II, Amaranth, Ponceau BS and Ponceau S azo dyes. Azo1 represents the first azoreductase to be identified and characterized from human skin microflora. PMID:15870453

  3. Dual gas-diffusion membrane- and mediatorless dihydrogen/air-breathing biofuel cell operating at room temperature

    Science.gov (United States)

    Xia, Hong-qi; So, Keisei; Kitazumi, Yuki; Shirai, Osamu; Nishikawa, Koji; Higuchi, Yoshiki; Kano, Kenji

    2016-12-01

    A membraneless direct electron transfer (DET)-type dihydrogen (H2)/air-breathing biofuel cell without any mediator was constructed wherein bilirubin oxidase from Myrothecium verrucaria (BOD) and membrane-bound [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F (MBH) were used as biocatalysts for the cathode and the anode, respectively, and Ketjen black-modified water proof carbon paper (KB/WPCC) was used as an electrode material. The KB/WPCC surface was modified with 2-aminobenzoic acid and p-phenylenediamine, respectively, to face the positively charged electron-accepting site of BOD and the negatively charged electron-donating site of MBH to the electrode surface. A gas-diffusion system was employed for the electrodes to realize high-speed substrate supply. As result, great improvement in the current density of O2 reduction with BOD and H2 reduction with MBH were realized at negatively and postively charged surfaces, respectively. Gas diffusion system also suppressed the oxidative inactivation of MBH at high electrode potentials. Finally, based on the improved bioanode and biocathode, a dual gas-diffusion membrane- and mediatorless H2/air-breathing biofuel cell was constructed. The maximum power density reached 6.1 mW cm-2 (at 0.72 V), and the open circuit voltage was 1.12 V using 1 atm of H2 gas as a fuel at room temperature and under passive and quiescent conditions.

  4. Crystal and NMR Structures of a Peptidomimetic β-Turn That Provides Facile Synthesis of 13-Membered Cyclic Tetrapeptides.

    Science.gov (United States)

    Cameron, Alan J; Squire, Christopher J; Edwards, Patrick J B; Harjes, Elena; Sarojini, Vijayalekshmi

    2017-12-14

    Herein we report the unique conformations adopted by linear and cyclic tetrapeptides (CTPs) containing 2-aminobenzoic acid (2-Abz) in solution and as single crystals. The crystal structure of the linear tetrapeptide H 2 N-d-Leu-d-Phe-2-Abz-d-Ala-COOH (1) reveals a novel planar peptidomimetic β-turn stabilized by three hydrogen bonds and is in agreement with its NMR structure in solution. While CTPs are often synthetically inaccessible or cyclize in poor yield, both 1 and its N-Me-d-Phe analogue (2) adopt pseudo-cyclic frameworks enabling near quantitative conversion to the corresponding CTPs 3 and 4. The crystal structure of the N-methylated peptide (4) is the first reported for a CTP containing 2-Abz and reveals a distinctly planar 13-membered ring, which is also evident in solution. The N-methylation of d-Phe results in a peptide bond inversion compared to the conformation of 3 in solution. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Correlating PSf Support Physicochemical Properties with the Formation of Piperazine-Based Polyamide and Evaluating the Resultant Nanofiltration Membrane Performance

    Directory of Open Access Journals (Sweden)

    Micah Belle Marie Yap Ang

    2017-10-01

    Full Text Available Membrane support properties influence the performance of thin-film composite nanofiltration membranes. We fabricated several polysulfone (PSf supports. The physicochemical properties of PSf were altered by adding polyethylene glycol (PEG of varying molecular weights (200–35,000 g/mol. This alteration facilitated the formation of a thin polyamide layer on the PSf surface during the interfacial polymerization reaction involving an aqueous solution of piperazine containing 4-aminobenzoic acid and an organic solution of trimesoyl chloride. Attenuated total reflectance-Fourier transform infrared validated the presence of PEG in the membrane support. Scanning electron microscopy and atomic force microscopy illustrated that the thin-film polyamide layer morphology transformed from a rough to a smooth surface. A cross-flow filtration test indicated that a thin-film composite polyamide membrane comprising a PSf support (TFC-PEG20k with a low surface porosity, small pore size, and suitable hydrophilicity delivered the highest water flux and separation efficiency (J = 81.1 ± 6.4 L·m−2·h−1, RNa2SO4 = 91.1% ± 1.8%, and RNaCl = 35.7% ± 3.1% at 0.60 MPa. This membrane had a molecular weight cutoff of 292 g/mol and also a high rejection for negatively charged dyes. Therefore, a PSf support exhibiting suitable physicochemical properties endowed a thin-film composite polyamide membrane with high performance.

  6. Single tag for total carbohydrate analysis.

    Science.gov (United States)

    Anumula, Kalyan Rao

    2014-07-15

    Anthranilic acid (2-aminobenzoic acid, 2-AA) has the remarkable property of reacting rapidly with every type of reducing carbohydrate. Reactivity of 2-AA with carbohydrates in aqueous solutions surpasses all other tags reported to date. This unique capability is attributed to the strategically located -COOH which accelerates Schiff base formation. Monosaccharides, oligosaccharides (N-, O-, and lipid linked and glycans in secretory fluids), glycosaminoglycans, and polysaccharides can be easily labeled with 2-AA. With 2-AA, labeling is simple in aqueous solutions containing proteins, peptides, buffer salts, and other ingredients (e.g., PNGase F, glycosidase, and transferase reaction mixtures). In contrast, other tags require relatively pure glycans for labeling in anhydrous dimethyl sulfoxide-acetic acid medium. Acidic conditions are known to cause desialylation, thus requiring a great deal of attention to sample preparation. Simpler labeling is achieved with 2-AA within 30-60 min in mild acetate-borate buffered solution. 2-AA provides the highest sensitivity and resolution in chromatographic methods for carbohydrate analysis in a simple manner. Additionally, 2-AA is uniquely qualified for quantitative analysis by mass spectrometry in the negative mode. Analyses of 2-AA-labeled carbohydrates by electrophoresis and other techniques have been reported. Examples cited here demonstrate that 2-AA is the universal tag for total carbohydrate analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Synthesis and characterization of novel bioactive 1,2,4-oxadiazole natural product analogs bearing the N-phenylmaleimide and N-phenylsuccinimide moieties

    Directory of Open Access Journals (Sweden)

    Catalin V. Maftei

    2013-10-01

    Full Text Available Taking into consideration the biological activity of the only natural products containing a 1,2,4-oxadiazole ring in their structure (quisqualic acid and phidianidines A and B, the natural product analogs 1-(4-(3-tert-butyl-1,2,4-oxadiazol-5-ylphenylpyrrolidine-2,5-dione (4 and 1-(4-(3-tert-butyl-1,2,4-oxadiazol-5-ylphenyl-1H-pyrrole-2,5-dione (7 were synthesized starting from 4-(3-tert-butyl-1,2,4-oxadiazol-5-ylaniline (1 in two steps by isolating the intermediates 4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-ylphenylamino-4-oxobutanoic acid (3 and (Z-4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-ylphenylamino-4-oxobut-2-enoic acid (6. The two natural product analogs 4 and 7 were then tested for antitumor activity toward a panel of 11 cell lines in vitro by using a monolayer cell-survival and proliferation assay. Compound 7 was the most potent and exhibited a mean IC50 value of approximately 9.4 µM. Aniline 1 was synthesized by two routes in one-pot reactions starting from tert-butylamidoxime and 4-aminobenzoic acid or 4-nitrobenzonitrile. The structures of compounds 1, 2, 4, 5 and 6 were confirmed by X-ray crystallography.

  8. Crystal and molecular structure of neodymium (3) p-aminobenzoaate

    International Nuclear Information System (INIS)

    Khiyalov, M.S.; Amiraslanov, I.R.; Mamedov, Kh.S.; Movsumov, Eh.M.

    1981-01-01

    X-ray structural study (lambda MoKsub(α), automatic diffractometer, the method of heavy atom, anisotropic specification) of neodymium (3) n-aminobenzoate has been carried out. The crystals are monoclinic: a=9.882 (5), b=22.810 (12), c=9.851 (8)A, β=100.02 (5)deg, v=2186.59 A 3 , Z=4, sp. gr. P2 1 /n, R=0.046. The crystal structure of Nd(OOCC 6 H 4 NH 2 ) 3 xH 2 O consists of dimer-periodic layers alternating along the b axis. Surrounding of Nd atom in the chain is formed with four oxygen atoms of four carboxyl groups of bidentate-bridge and one carboxyl bidentate-cyclic ligands, one water molecule and N atom of ligand aminogroup from the neigbouring chain. The atom simultaneously bonds the neighbouring chains into continuous layer. The mean distances Nd-O, and Nd-N are equal to 2.45 and 2.74 A. An attempt to determine hydrogen atom coordinates has failed [ru

  9. G-CSF receptor-binding cyclic peptides designed with artificial amino-acid linkers

    International Nuclear Information System (INIS)

    Shibata, Kenji; Maruyama-Takahashi, Kumiko; Yamasaki, Motoo; Hirayama, Noriaki

    2006-01-01

    Designing small molecules that mimic the receptor-binding local surface structure of large proteins such as cytokines or growth factors is fascinating and challenging. In this study, we designed cyclic peptides that reproduce the receptor-binding loop structures of G-CSF. We found it is important to select a suitable linker to join two or more discontinuous sequences and both termini of the peptide corresponding to the receptor-binding loop. Structural simulations based on the crystallographic structure of KW-2228, a stable and potent analog of human G-CSF, led us to choose 4-aminobenzoic acid (Abz) as a part of the linker. A combination of 4-Abz with β-alanine or glycine, and disulfide bridges between cysteins or homocysteins, gave a structure suitable for receptor binding. In this structure, the side-chains of several amino acids important for the interactions with the receptor are protruding from one side of the peptide ring. This artificial peptide showed G-CSF antagonistic activity in a cell proliferation assay

  10. Data for analysis of mannose-6-phosphate glycans labeled with fluorescent tags

    Directory of Open Access Journals (Sweden)

    Ji-Yeon Kang

    2016-06-01

    Full Text Available Mannose-6-phosphate (M-6-P glycan plays an important role in lysosomal targeting of most therapeutic enzymes for treatment of lysosomal storage diseases. This article provides data for the analysis of M-6-P glycans by high-performance liquid chromatography (HPLC and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry. The identities of M-6-P glycan peaks in HPLC profile were confirmed by measuring the masses of the collected peak eluates. The performances of three fluorescent tags (2-aminobenzoic acid [2-AA], 2-aminobenzamide [2-AB], and 3-(acetyl-amino-6-aminoacridine [AA-Ac] were compared focusing on the analysis of bi-phosphorylated glycan (containing two M-6-Ps. The bi-phosphorylated glycan analysis is highly affected by the attached fluorescent tag and the hydrophilicity of elution solvent used in HPLC. The data in this article is associated with the research article published in “Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans” (Kang et al., 2016 [1].

  11. Nanocomposite films containing Au nanoparticles formed by electrochemical reduction of metal ions in the multilayer films as electrocatalyst for dioxygen reduction

    International Nuclear Information System (INIS)

    Huang Minghua; Shen Yan; Cheng Wenlong; Shao Yong; Sun Xuping; Liu Baifeng; Dong Shaojun

    2005-01-01

    Through electrostatic layer-by-layer assembly, AuCl 4 - anions and [tetrakis(N-methylpyridyl)porphyrinato] cobalt (CoTMPyP) cations were alternately deposited on indium tin oxide (ITO) substrates, and 4-aminobenzoic acid modified glassy carbon electrode. Electrochemical reduction of AuCl 4 - anions sandwiched between CoTMPyP layers leads to the in situ formation of Au nanoparticles in the multilayer films. Regular growth of the multilayer films is monitored by UV-vis spectroscopy. UV-vis spectroscopy, X-ray photoelectron spectroscopy and cyclic voltammetry confirm the formation of Au nanoparticles in the multilayer films after electrochemical reduction of AuCl 4 - anions. Atomic force spectroscopy verifies that the as-prepared Au nanoparticles are uniformly distributed with average particles diameters of 20-25 nm. The resulting composite films containing Au nanoparticles with high stability exhibit high electrocatalytic activity for the reduction of dioxygen. Rotating disk electrode voltammetry and rotating ring-disk electrode voltammetry demonstrate the Au nanoparticles-containing films can catalyze two-electron reduction of O 2 to H 2 O 2 in O 2 -saturated 0.1 M H 2 SO 4 solution

  12. Investigations on aberrant glycosylation of glycosphingolipids in colorectal cancer tissues using liquid chromatography and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS).

    Science.gov (United States)

    Holst, Stephanie; Stavenhagen, Kathrin; Balog, Crina I A; Koeleman, Carolien A M; McDonnell, Liam M; Mayboroda, Oleg A; Verhoeven, Aswin; Mesker, Wilma E; Tollenaar, Rob A E M; Deelder, André M; Wuhrer, Manfred

    2013-11-01

    Cancer is a leading cause of death and alterations of glycosylation are characteristic features of malignant cells. Colorectal cancer is one of the most common cancers and its exact causes and biology are not yet well understood. Here, we compared glycosylation profiles of colorectal tumor tissues and corresponding control tissues of 13 colorectal cancer patients to contribute to the understanding of this cancer. Using MALDI-TOF(/TOF)-MS and 2-dimensional LC-MS/MS we characterized enzymatically released and 2-aminobenzoic acid labeled glycans from glycosphingolipids. Multivariate data analysis revealed significant differences between tumor and corresponding control tissues. Main discriminators were obtained, which represent the overall alteration in glycosylation of glycosphingolipids during colorectal cancer progression, and these were found to be characterized by (1) increased fucosylation, (2) decreased acetylation, (3) decreased sulfation, (4) reduced expression of globo-type glycans, as well as (5) disialyl gangliosides. The findings of our current research confirm former reports, and in addition expand the knowledge of glycosphingolipid glycosylation in colorectal cancer by revealing new glycans with discriminative power and characteristic, cancer-associated glycosylation alterations. The obtained discriminating glycans can contribute to progress the discovery of biomarkers to improve diagnostics and patient treatment.

  13. Photoaddition of p-aminobenzoil acid to thymine and thymidine

    International Nuclear Information System (INIS)

    Shaw, A.A.; Wainschel, L.A.; Shetlar, M.D.

    1992-01-01

    Several studies in the literature have shown that DNA is damaged after UV irradiation in the presence of the sunscreen agent p-aminobenzoic acid (PABA), both in vivo and in vitro. One type of damage has been shown to be the result of increased yields of pyrimidime cyclobutane dimer formation. However, it has been suggested that other types of lesions are produced as well. We have studied the photochemistry of the thymine-PABA and thymidine-PABA systems and report here the isolation and characterization of thymine-PABA and thymidine-PABA photoadducts. These products have been identified, respectively as 5-(2-amino-5-carboxyphenyl)-5,6-dihydrothymine and isomeric forms of 5-(2-amino-5-carboxyphenyl)-5,6-dihydrothymidine. The quantum yields for the formation of these ducts in deaerated aqueous solutions at pH 7.0 have been determined to be 9.5 x 10 -4 and 4.3 x 10 -3 for the thymine and thymidine based adducts respectively. A pH profile for the thymine-PABA system indicated a maximum quantum yield for adduct formation at pH 6.5, although it could be detected over the whole pH range studied (pH 3.5-11.0). (Author)

  14. Modified Synthesis of Erlotinib Hydrochloride

    Directory of Open Access Journals (Sweden)

    Leila Barghi

    2012-06-01

    Full Text Available Purpose: An improved and economical method has been described for the synthesis of erlotinib hydrochloride, as a useful drug in treatment of non-small-cell lung cancer. Methods: Erlotinib hydrochloride was synthesized in seven steps starting from 3, 4-dihydroxy benzoic acid. In this study, we were able to modify one of the key steps which involved the reduction of the 6-nitrobenzoic acid derivative to 6-aminobenzoic acid derivative. An inexpensive reagent such as ammonium formate was used as an in situ hydrogen donor in the presence of palladium/charcoal (Pd/C instead of hydrogen gas at high pressure. Results: This proposed method proceeded with 92% yield at room temperature. Synthesis of erlotinib was completed in 7 steps with overall yield of 44%.Conclusion: From the results obtained it can be concluded that the modified method eliminated the potential danger associated with the use of hydrogen gas in the presence of flammable catalysts. It should be mentioned that the catalyst was recovered after the reaction and could be used again.

  15. Improvement of Folate Biosynthesis by Lactic Acid Bacteria Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Norfarina Muhamad Nor

    2010-01-01

    Full Text Available Lactic acid bacteria (Lactococcus lactis NZ9000, Lactococcus lactis MG1363, Lactobacillus plantarum I-UL4 and Lactobacillus johnsonii DSM 20553 have been screened for their ability to produce folate intracellularly and/or extracellularly. L. plantarum I-UL4 was shown to be superior producer of folate compared to other strains. Statistically based experimental designs were used to optimize the medium formulation for the growth of L. plantarum I-UL4 and folate biosynthesis. The optimal values of important factors were determined by response surface methodology (RSM. The effects of carbon sources, nitrogen sources and para-aminobenzoic acid (PABA concentrations on folate biosynthesis were determined prior to RSM study. The biosynthesis of folate by L. plantarum I-UL4 increased from 36.36 to 60.39 µg/L using the optimized medium formulation compared to the selective Man de Rogosa Sharpe (MRS medium. Conditions for the optimal growth of L. plantarum I-UL4 and folate biosynthesis as suggested by RSM were as follows: lactose 20 g/L, meat extract 16.57 g/L and PABA 10 µM.

  16. Kinetics and Mechanistic Chemistry of Oxidation of Butacaine Sulfate by Chloramine-B in Acid Medium

    International Nuclear Information System (INIS)

    Shubha, Jayachamarajapura Pranesh; Kotabagi, Vinutha; Puttaswamy

    2012-01-01

    Butacaine sulfate is an ester of p-aminobenzoic acid which has been widely used as a local anaesthetic and it is a long standing agent particularly for spinal anaesthesia. For this reason, a kinetic study of oxidation of butacaine sulfate by sodium N-chlorobenzenesulfonamide (chloramine-B or CAB) has been carried out in HClO 4 medium at 303 K in order to explore this redox system mechanistic chemistry. The rate shows a first-order dependence on both [CAB] o , and [substrate] o , and a fractional-order dependence on acid concentration. Decrease of dielectric constant of the medium, by adding methanol, increases the rate of the reaction. Variation of ionic strength and addition of benzenesulfonamide or NaCl have no significant effect on the rate. The reaction was studied at different temperatures and the activation parameters have been evaluated. The stoichiometry of the reaction has been found to be 1:2 and the oxidation products have been identified by spectral analysis. The observed results have been explained by plausible mechanism and the related rate law has been deduced

  17. Tyrocidine A Analogues Bearing the Planar d-Phe-2-Abz Turn Motif: How Conformation Impacts Bioactivity.

    Science.gov (United States)

    Cameron, Alan J; Edwards, Patrick J B; Harjes, Elena; Sarojini, Vijayalekshmi

    2017-12-14

    The d-Phe-Pro β-turn of the cyclic β-hairpin antimicrobial decapeptide tyrocidine A, (Tyrc A) was substituted with the d-Phe-2-aminobenzoic acid (2-Abz) motif in a synthetic analogue (1). The NMR structure of 1 demonstrated that compound 1 retained the β-hairpin structure of Tyrc A with additional planarity, resulting in approximately 30-fold reduced hemolysis than Tyrc A. Although antibacterial activity was partially compromised, a single Gln to Lys substitution (2) restored activity equivalent to Tyrc A against S. aureus, enhanced activity against two Gram negative strains and maintained the reduced hemeloysis of 1. Analysis by transmission electron microscopy (TEM) suggested a membrane lytic mechanism of action for these peptides. Compound 2 also exhibits nanomolar antifungal activity in synergy with amphotericin B. The d-Phe-2-Abz turn may serve as a tool for the synthesis of structurally predictable β-hairpin libraries. Unlike traditional β-turn motifs such as d-Pro-Gly, both the 2-Abz and d-Phe rings may be further functionalized.

  18. Is energy pooling necessary in ultraviolet matrix-assisted laser desorption/ionization?

    Science.gov (United States)

    Lin, Hou-Yu; Song, Botao; Lu, I-Chung; Hsu, Kuo-Tung; Liao, Chih-Yu; Lee, Yin-Yu; Tseng, Chien-Ming; Lee, Yuan-Tseh; Ni, Chi-Kung

    2014-01-15

    Energy pooling has been suggested as the key process for generating the primary ions during ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI). In previous studies, decreases in fluorescence quantum yields as laser fluence increased for 2-aminobenzoic acid, 2,5-dihydroxybenzoic acid (2,5-DHB), and 3-hydroxypicolinic acid were used as evidence of energy pooling. This work extends the research to other matrices and addresses whether energy pooling is a universal property in UV-MALDI. Energy pooling was investigated in a time-resolved fluorescence experiment by using a short laser pulse (355 nm, 20 ps pulse width) for excitation and a streak camera (1 ps time resolution) for fluorescence detection. The excited-state lifetime of 2,5-DHB decreased with increases in laser fluence. This suggests that a reaction occurs between two excited molecules, and that energy pooling may be one of the possible reactions. However, the excited-state lifetime of 2,4,6-trihydroxyacetophenone (THAP) did not change with increases in laser fluence. The upper limit of the energy pooling rate constant for THAP is estimated to be approximately 100-500 times smaller than that of 2,5-DHB. The small energy pooling rate constant for THAP indicates that the potential contribution of the energy pooling mechanism to the generation of THAP matrix primary ions should be reconsidered. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Nutritional optimization for anaerobic growth of Bacillus steaothermophilus LLD-16

    Directory of Open Access Journals (Sweden)

    Muhammad Javed

    2016-04-01

    Full Text Available In this study, a range of nutritional supplements including twenty amino acids, major vitamins and four nucleic acid bases were exploited as added-value supplements for the growth of a lactate-minus (ldh mutant Bacillus stearothermophilus LLD-16 under anaerobic environment. The chemostat studies revealed that five amino acids that includes aspartate, glutamate, isoleucine, methionine, and serine were essential for persuaded growth of B. stearothermophilus LLD-16. The anaerobic batch studies showed that a number of nutritional supplements, such as, p-aminobenzoic acid (PABA, folic acid, pantothenic acid, adenine, glycine, leucine, tryptophan, proline, alanine and α-ketoglutarate, when added individually, improved the biomass levels. In contrast, the higher concentrations of cyanocobalamine or biotin, guanine, uracil and isoleucine were found inhibitory. Furthermore, the study explains why the highest biomass formation cannot necessarily be achieved on the richest mixture of amino acids, and the inadequacy of the biosynthetic machinery is very much dependent on the growth conditions of the microorganism.

  20. Small scale affinity purification and high sensitivity reversed phase nanoLC-MS N-glycan characterization of mAbs and fusion proteins.

    Science.gov (United States)

    Higel, Fabian; Seidl, Andreas; Demelbauer, Uwe; Sörgel, Fritz; Frieß, Wolfgang

    2014-01-01

    N-glycosylation is a complex post-translational modification with potential effects on the efficacy and safety of therapeutic proteins and known influence on the effector function of biopharmaceutical monoclonal antibodies (mAbs). Comprehensive characterization of N-glycosylation is therefore important in biopharmaceutical development. In early development, e.g. during pool or clone selection, however, only minute protein amounts of multiple samples are available for analytics. High sensitivity and high throughput methods are thus needed. An approach based on 96-well plate sample preparation and nanoLC-MS of 2- anthranilic acid or 2-aminobenzoic acid (AA) labeled N-glycans for the characterization of biopharmaceuticals in early development is reported here. With this approach, 192 samples can be processed simultaneously from complex matrices (e.g., cell culture supernatant) to purified 2-AA glycans, which are then analyzed by reversed phase nanoLC-MS. Attomolar sensitivity has been achieved by use of nanoelectrospray ionization, resulting in detailed glycan maps of mAbs and fusion proteins that are exemplarily shown in this work. Reproducibility, robustness and linearity of the approach are demonstrated, making use in a routine manner during pool or clone selection possible. Other potential fields of application, such as glycan biomarker discovery from serum samples, are also presented.

  1. Hexose rearrangements upon fragmentation of N-glycopeptides and reductively aminated N-glycans.

    Science.gov (United States)

    Wuhrer, Manfred; Koeleman, Carolien A M; Deelder, André M

    2009-06-01

    Tandem mass spectrometry of glycans and glycoconjugates in protonated form is known to result in rearrangement reactions leading to internal residue loss. Here we studied the occurrence of hexose rearrangements in tandem mass spectrometry of N-glycopeptides and reductively aminated N-glycans by MALDI-TOF/TOF-MS/MS and ESI-ion trap-MS/MS. Fragmentation of proton adducts of oligomannosidic N-glycans of ribonuclease B that were labeled with 2-aminobenzamide and 2-aminobenzoic acid resulted in transfer of one to five hexose residues to the fluorescently tagged innermost N-acetylglucosamine. Glycopeptides from various biological sources with oligomannosidic glycans were likewise shown to undergo hexose rearrangement reactions, resulting in chitobiose cleavage products that have acquired one or two hexose moieties. Tryptic immunoglobulin G Fc-glycopeptides with biantennary N-glycans likewise showed hexose rearrangements resulting in hexose transfer to the peptide moiety retaining the innermost N-acetylglucosamine. Thus, as a general phenomenon, tandem mass spectrometry of reductively aminated glycans as well as glycopeptides may result in hexose rearrangements. This characteristic of glycopeptide MS/MS has to be considered when developing tools for de novo glycopeptide structural analysis.

  2. Electron detachment dissociation of fluorescently labeled sialylated oligosaccharides.

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2011-12-01

    We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared with infrared multiphoton dissociation. Neutral losses and satellite ions such as C-2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA-labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared with 2-AA-labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Investigations on Aberrant Glycosylation of Glycosphingolipids in Colorectal Cancer Tissues Using Liquid Chromatography and Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-TOF-MS)*

    Science.gov (United States)

    Holst, Stephanie; Stavenhagen, Kathrin; Balog, Crina I. A.; Koeleman, Carolien A. M.; McDonnell, Liam M.; Mayboroda, Oleg A.; Verhoeven, Aswin; Mesker, Wilma E.; Tollenaar, Rob A. E. M.; Deelder, André M.; Wuhrer, Manfred

    2013-01-01

    Cancer is a leading cause of death and alterations of glycosylation are characteristic features of malignant cells. Colorectal cancer is one of the most common cancers and its exact causes and biology are not yet well understood. Here, we compared glycosylation profiles of colorectal tumor tissues and corresponding control tissues of 13 colorectal cancer patients to contribute to the understanding of this cancer. Using MALDI-TOF(/TOF)-MS and 2-dimensional LC-MS/MS we characterized enzymatically released and 2-aminobenzoic acid labeled glycans from glycosphingolipids. Multivariate data analysis revealed significant differences between tumor and corresponding control tissues. Main discriminators were obtained, which represent the overall alteration in glycosylation of glycosphingolipids during colorectal cancer progression, and these were found to be characterized by (1) increased fucosylation, (2) decreased acetylation, (3) decreased sulfation, (4) reduced expression of globo-type glycans, as well as (5) disialyl gangliosides. The findings of our current research confirm former reports, and in addition expand the knowledge of glycosphingolipid glycosylation in colorectal cancer by revealing new glycans with discriminative power and characteristic, cancer-associated glycosylation alterations. The obtained discriminating glycans can contribute to progress the discovery of biomarkers to improve diagnostics and patient treatment. PMID:23878401

  4. Quantification and characterization of enzymatically produced hyaluronan with fluorophore-assisted carbohydrate electrophoresis.

    Science.gov (United States)

    Kooy, Floor K; Ma, Muyuan; Beeftink, Hendrik H; Eggink, Gerrit; Tramper, Johannes; Boeriu, Carmen G

    2009-01-15

    Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA oligosaccharides, which can be enzymatically produced using Pasteurella multocida hyaluronan synthase (PmHAS). We have developed a sensitive, simple, and fast method, based on fluorophore-assisted carbohydrate electrophoresis (FACE), for characterization and quantification of polymerization products. A chromatographic pure fluorescent template was synthesized from HA tetrasaccharide (HA4) and 2-aminobenzoic acid. HA4-fluor and HA4 were used as template for PmHAS-mediated polymerization of nucleotide sugars. All products, fluorescent and nonfluorescent, were analyzed with gel electrophoresis and quantified using lane densitometry. Comparison of HA4- and HA4-fluor-derived polymers showed that the fluorophore did not negatively influence the PmHAS-mediated polymerization. Only even-numbered oligosaccharide products were observed using HA4-fluor or HA4 as template. The fluorophore intensity was linearly related to its concentration, and the limit of detection was determined to be 7.4pmol per product band. With this assay, we can now differentiate oligosaccharides of size range DP2 (degree of polymerization 2) to approximately DP400, monitor the progress of polymerization reactions, and measure subtle differences in polymerization rate. Quantifying polymerization products enables us to study the influence of experimental conditions on HA synthesis.

  5. Analysis of N-acetylaminosugars by CE: a comparative derivatization study.

    Science.gov (United States)

    Rustighi, Isabella; Campa, Cristiana; Rossi, Marco; Semeraro, Sabrina; Vetere, Amedeo; Gamini, Amelia

    2009-08-01

    N-linked or O-linked glycans derived from glycoprotein processing carry, an N-acetylglucosamine or an N-acetylgalactosamine respectively, at their reducing termini. The presence of the N-acetylamino group on C-2 of reducing sugar residues has been reported to hamper the derivatization reaction with a chromophore at the anomeric centre. In this paper N-acetyllactosamine, N-acetylglucosamine, N-acetylgalactosamine and several other neutral monosaccharides are coupled to three different dyes (4-aminobenzonitrile, 2-aminopyridine, 2-aminobenzoic acid (2-AA)) by reductive amination and analysed by CE with UV detection. The 2-AA derivatives showed the lowest concentration detection limits, varying approximately in the 2-3 muM range for the saccharides tested including the N-acetamido ones. The possibility to separate and detect with the same sensitivity ten 2-AA-labelled monosaccharides mainly found in mammalian or plant glycoproteins in a single CE run is highlighted. The analysis has been carried out in less than 25 min using the borate-complexation method in CZE mode. The influence of the strength of the acid used as catalyst in the chemical modification of the sugars with 2-AA is also shortly addressed.

  6. Analysis of O-glycans as 9-fluorenylmethyl derivatives and its application to the studies on glycan array.

    Science.gov (United States)

    Yamada, Keita; Hirabayashi, Jun; Kakehi, Kazuaki

    2013-03-19

    A method is proposed for the analysis of O-glycans as 9-fluorenylmethyl (Fmoc) derivatives. After releasing the O-glycans from the protein backbone in the presence of ammonia-based media, the glycosylamines thus formed are conveniently labeled with Fmoc-Cl and analyzed by HPLC and MALDI-TOF MS after easy purification. Fmoc labeled O-glycans showed 3.5 times higher sensitivities than those labeled with 2-aminobenzoic acid in fluorescent detection. Various types of O-glycans having sialic acids, fucose, and/or sulfate residues were successfully labeled with Fmoc and analyzed by HPLC and MALDI-TOF MS. The method was applied to the comprehensive analysis of O-glycans expressed on MKN45 cells (human gastric adenocarcinoma). In addition, Fmoc-derivatized O-glycans were easily converted to free hemiacetal or glycosylamine-form glycans that are available for fabrication of glycan array and neoglycoproteins. To demonstrate the availability of our methods, we fabricate the glycan array with Fmoc labeled glycans derived from mucin samples and cancer cells. The model studies using the glycan array showed clear interactions between immobilized glycans and some lectins.

  7. A multi-method approach toward de novo glycan characterization: a Man-5 case study.

    Science.gov (United States)

    Prien, Justin M; Prater, Bradley D; Cockrill, Steven L

    2010-05-01

    Regulatory agencies' expectations for biotherapeutic approval are becoming more stringent with regard to product characterization, where minor species as low as 0.1% of a given profile are typically identified. The mission of this manuscript is to demonstrate a multi-method approach toward de novo glycan characterization and quantitation, including minor species at or approaching the 0.1% benchmark. Recently, unexpected isomers of the Man(5)GlcNAc(2) (M(5)) were reported (Prien JM, Ashline DJ, Lapadula AJ, Zhang H, Reinhold VN. 2009. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap mass spectrometry (MS). J Am Soc Mass Spectrom. 20:539-556). In the current study, quantitative analysis of these isomers found in commercial M(5) standard demonstrated that they are in low abundance (2-aminobenzoic acid to detect and chromatographically resolve multiple M(5) isomers in bovine ribonuclease B. With this multi-method approach, we have the capabilities to comprehensively characterize a biotherapeutic's glycan array in a de novo manner, including structural isomers at >/=0.1% of the total chromatographic peak area.

  8. Vibratory Reaction Unit for the Rapid Analysis of Proteins and Glycochains

    Directory of Open Access Journals (Sweden)

    Yukie Sasakura

    2007-01-01

    Full Text Available A protein digestion system using immobilized enzymes for protein identification and glycochain analyses has been developed, and a vibration reaction unit for micro-scale sample convection on an enzyme-immobilized solid surface was constructed. BSA as a model substrate was digested by this unit, and was successfully identified by mass spectrometry (MS analyses. Compared to the conventional liquid-phase digestion, the reaction unit increased the number of matched peptides from 9 to 26, protein score from 455 to 1247, and sequence coverage from 21% to 48%. Glycopeptidase F (NGF, an enzyme that cleaves N-glycans from glycoproteins, was also immobilized and used to remove the glycochains from human immunoglobulin G (IgG. Trypsin and NGF were immobilized on the same solid surface and used to remove glycochains from IgG in single-step. Glycochains were labeled with fluorescent reagent and analyzed by HPLC. Several peaks corresponding to the glycochains of IgG were detected. These results suggested that the single-step digestion system, by immobilized multiple enzymes (trypsin and NGF would be effective for the rapid structural analysis of glycoproteins.Abbreviations: BSA: bovine serum albumin; MS: mass spectrometry; NGF: glycopeptidase F; IgG: immunoglobulin G; PTM: post-translational modification; HPLC: high-performance liquid chromatography; PBS: phosphate-buffered saline; EDTA: ethylenediaminetetraacetic acid; DTT: dithiothreitol; RT: retention time; ABOE: p-aminobenzoic acid octyl ester; PDMS: polydimethylsiloxane; ArgC: endoprotease Arginine C.

  9. A stability comparison of redox-active layers produced by chemical coupling of an osmium redox complex to pre-functionalized gold and carbon electrodes

    International Nuclear Information System (INIS)

    Boland, Susan; Foster, Kevin; Leech, Donal

    2009-01-01

    The production of stable redox active layers on electrode surfaces is a key factor for the development of practical electronic and electrochemical devices. Here, we report on a comparison of the stability of redox layers formed by covalently coupling an osmium redox complex to pre-functionalized gold and graphite electrode surfaces. Pre-treatment of gold and graphite electrodes to provide surface carboxylic acid groups is achieved via classical thiolate self-assembled monolayer formation on gold surfaces and the electro-reduction of an in situ generated aryldiazonium salt from 4-aminobenzoic acid on gold, glassy carbon and graphite surfaces. These surfaces have been characterized by AFM and electrochemical blocking studies. The surface carboxylate is then used to tether an osmium complex, [Os(2,2'-bipyridyl) 2 (4-aminomethylpyridine)Cl]PF 6 , to provide a covalently bound redox active layer, E 0 '' of 0.29 V (vs. Ag/AgCl in phosphate buffer, pH 7.4), on the pre-treated electrodes. The aryldiazonium salt-treated carbon-based surfaces showed the greatest stability, represented by a decrease of <5% in the peak current for the Os(II/III) redox transition of the immobilized complex over a 3-day period, compared to a decrease of 19% and 14% for the aryldiazonium salt treated and thiolate treated gold surfaces, respectively, over the same period

  10. High refractive index organic–inorganic composites with TiO2 nanocrystal

    International Nuclear Information System (INIS)

    Yu, Yang-Yen; Yu, Hui-Huan

    2013-01-01

    Highly transparent polyimide–nanocrystalline-titania hybrid materials with a relatively high titania content (up to 90 wt.%) have been fabricated via sol–gel process. The organo-soluble polyimide was synthesized from 4,4′-(hexafluoroisopropylidene) diphthalic anhydride, 3,3′-Diaminodiphenyl sulfone, and 4-aminobenzoic acid. Such carboxylic acid end groups could provide the organic–inorganic bonding with titania. The images of atomic force and scanning electron microscope showed the well-dispersed nanocrystalline-titania. The analytical results of transmission electron microscope and X-ray diffractometer indicated that the formation of nanocrystalline-titania domains of around 3–4 nm in the hybrid films. The experimental results suggest that the prepared hybrid films have high thermal stability, good surface planarity, tunable refractive index (1.61 < n < 2.01), and optical transparency in the visible range. These results indicate that the polyimide–nanocrystalline-titania hybrid materials have potential applications for optical devices. - Highlights: ► Polyimide–titania hybrid materials with up to 90 wt.% titania via sol–gel process. ► The hybrid films are highly transparent. ► Organic–inorganic bonding through the carboxylic acid end groups of polymide. ► Nanocrystalline–titania domains in the hybrid films around 3–4 nm. ► High thermal stability, good surface planarity, tunable refractive index are obtained

  11. Coumarin- and Carboxyl-Functionalized Supramolecular Polybenzoxazines Form Miscible Blends with Polyvinylpyrrolidone

    Directory of Open Access Journals (Sweden)

    Ruey-Chorng Lin

    2017-04-01

    Full Text Available In this study, we synthesized a novel multifunctional benzoxazine monomer (Coumarin-COOH BZ, possessing both coumarin and COOH groups, through the reaction of 4-methyl-7-hydroxycoumarin, 4-aminobenzoic acid, and paraformaldehyde in 1,4-dioxane, with the structure confirmed using 1H and 13C nuclear magnetic resonance and Fourier transform infrared (FTIR spectroscopy. Differential scanning calorimetry (DSC, FTIR spectroscopy, and thermogravimetric analysis were then employed to monitor the thermal curing behavior of Coumarin-COOH BZ and its blends with poly(N-vinyl-2-pyrrolidone (PVP, both before and after photodimerization of the coumarin moieties. DSC revealed a single glass transition temperature for each Coumarin-COOH BZ/PVP blend composition; a large positive deviation based on the Kwei equation suggested that strong hydrogen bonding existed between the Coumarin-COOH BZ and PVP segments, confirmed through FTIR spectroscopic analyses. The thermal properties improved (i.e., increased glass transition and thermal degradation temperatures as a result of the increased crosslinking density after photodimerization under UV exposure.

  12. DSC and X-ray diffraction investigations of phase transitions in HxBABA and NBABA

    International Nuclear Information System (INIS)

    Usha Deniz, K.; Paranjpe, A.S.; Mirza, E.B.; Parvathanathan, P.S.; Patel, K.S.

    1979-01-01

    The phase transitions and the heats of transformation, of the hexyl (HxBABA) and nonyl (NBABA) members of the series of compounds, p-n-Alkoxybenzylidene-p-Aminobenzoic Acids, have been studied by DSC in the temperature range, - 100 0 C to 300 0 C. A scheme of transitions has been proposed for each of the compounds. X-ray diffraction measurements have been done in the smectic C(Ssub(c)) and nematic (N) phases of these materials. The results reveal that (1) the Ssub(c) phase in both compounds is of the C 1 -type, (2) Ssub(c)-type order is seen throughout the nematic phase in HxBABA, whereas in NBABA, it is seen only in the neighbourhood of the Ssub(c)-N transition, (3) the temperature dependence of the smectic layer thickness, d, and of the directly measured tilt angle, theta sub(t,d), reflect faithfully the strength of the first order transition, Ssub(c)-N, and (4) there is a marked difference between the values and the temperature variations of theta sub(t,d) and theta sub(t,c) (tilt angle calculated from d) which is not completely understood, at present

  13. The effect of ultraviolet light on the cyclic nucleotide system of human fibroblasts

    International Nuclear Information System (INIS)

    Fertel, R.H.; Tejwani, G.A.; Albrightson, C.R.; Hart, R.W.

    1981-01-01

    The concentrations of cyclic AMP and cyclic GMP in in human skin fibroblasts in culture were determined after exposing the cells to varying fluences of UV (254 nm) light. The cyclic nucleotide concentrations of cells irradiated in the log phase of growth were unchanged relative to controls. In contrast, there was a rise in the concentration of cyclic AMP in cells irradiated after they reached confluency. The increase in concentration was observed as early as 30 min after irradiation, reached a maximum of about 200% of control at 4 to 6 h after exposure, and returned to control values by 24 h after irradiation. The effect was proportional to a UV fluence from 5 to 20 J/m 2 , and was blocked by the addition of the UV absorbing agent para-aminobenzoic acid. In contrast, the results indicated that UV light had no effect on the concentration of cyclic GMP in human fibroblast cell cultures. Because of the importance of cyclic nucleotides in the regulation of cellular function, it is reasonable to hypothesize that changes in cyclic AMP induced by UV light may effect the extranuclear functions of irradiated cells. (author)

  14. Degradation of N-heterocyclic indole by a novel endophytic fungus Phomopsis liquidambari.

    Science.gov (United States)

    Chen, Yan; Xie, Xing-Guang; Ren, Cheng-Gang; Dai, Chuan-Chao

    2013-02-01

    A broad-spectrum endophytic Phomopsis liquidambari, was used to degrade environmental pollutant indole. In the condition of using indole as sole carbon and nitrogen source, the optimum concentration of indole supplied was determined to be 100 mg L(-1), with 41.7% ratio of indole degradation within 120 h. Exogenous addition of plant litter significantly increased indole degradation to 99.1% within 60 h. Indole oxidation to oxindole and isatin were the key steps limiting indole degradation. Plant litter addition induced fungus to produce laccase and LiP to non-specific oxidize indole. The results of fungal metabolites pathway through HPLC-MS and NMR analysis showed that indole was firstly oxidized to oxindole and isatin, and deoxidated to indolenie-2-dione, then hydroxylated to 2-dioxindole, which pyridine ring were cleaved through C-N position and changed to 2-aminobenzoic acid. Such metabolic pathway was similar with bacterial degradation of indole-3-acetic acid in plant. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Comparison of isocratic retention models for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

    Science.gov (United States)

    Česla, Petr; Vaňková, Nikola; Křenková, Jana; Fischer, Jan

    2016-03-18

    In this work, we have investigated retention of maltooligosaccharides and their fluorescent derivatives in hydrophilic interaction liquid chromatography using four different stationary phases. The non-derivatized maltooligosaccharides (maltose to maltoheptaose) and their derivatives with 2-aminobenzoic acid, 2-aminobenzamide, 2-aminopyridine and 8-aminonaphthalene-1,3,6-trisulfonic acid were analyzed on silica gel, aminopropyl silica, amide (carbamoyl-bonded silica) and ZIC-HILIC zwitterionic sulfobetain bonded phase. The partitioning of the analytes between the bulk mobile phase and adsorbed water-rich layer, polar and ionic interactions of analytes with stationary phase have been evaluated and compared. The effects of the mobile phase additives (0.1% (v/v) of acetic acid and ammonium acetate in concentration range 5-30 mmol L(-1)) on retention were described. The suitability of different models for prediction of retention was tested including linear solvent strength model, quadratic model, mixed-mode model, and empirical Neue-Kuss model. The mixed-mode model was extended to the parameter describing the contribution of monomeric glucose unit to the retention of non-derivatized and derivatized maltooligosaccharides, which was used for evaluation of contribution of both, oligosaccharide backbone and end-group to retention. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Quantitative investigations of xylose and arabinose substituents in hydroxypropylated and hydroxyvinylethylated arabinoxylans.

    Science.gov (United States)

    Lorenz, Dominic; Knöpfle, Anna; Akil, Youssef; Saake, Bodo

    2017-11-01

    The chemical structures obtained by the modification of arabinoxylans with the cyclic carbonates propylene carbonate (PC) and 4-vinyl-1,3-dioxolan-2-one (VEC) with varying degrees of substitution were investigated. Therefore, a new analytical method was developed that is based on a microwave-assisted hydrolysis of the polysaccharides with trifluoroacetic acid and the reductive amination with 2-aminobenzoic acid. The peak assignment was achieved by HPLC-MS and the carbohydrate derivatives were quantified by HPLC-fluorescence. The obtained maximum molar substitution of PC-derivatized xylan (X HP ) was 1.8; the molar substitution of VEC-derivatized xylan (X HVE ) was 2.3. Investigations of xylose and arabinose based mono- and disubstituted derivatives revealed a preferred reaction of the cyclic carbonates with arabinose. Conversion rates were up to 2.4 times higher for monosubstitution and up to 3.0 times for disubstitution compared to xylose. Furthermore, the reaction with VEC was preferred due to higher reactivity of the newly introduced side chains. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. A validated bioanalytical HPLC method for pharmacokinetic evaluation of 2-deoxyglucose in human plasma.

    Science.gov (United States)

    Gounder, Murugesan K; Lin, Hongxia; Stein, Mark; Goodin, Susan; Bertino, Joseph R; Kong, Ah-Ng Tony; DiPaola, Robert S

    2012-05-01

    2-Deoxyglucose (2-DG), an analog of glucose, is widely used to interfere with glycolysis in tumor cells and studied as a therapeutic approach in clinical trials. To evaluate the pharmacokinetics of 2-DG, we describe the development and validation of a sensitive HPLC fluorescent method for the quantitation of 2-DG in plasma. Plasma samples were deproteinized with methanol and the supernatant was dried at 45°C. The residues were dissolved in methanolic sodium acetate-boric acid solution. 2-DG and other monosaccharides were derivatized to 2-aminobenzoic acid derivatives in a single step in the presence of sodium cyanoborohydride at 80°C for 45 min. The analytes were separated on a YMC ODS C₁₈ reversed-phase column using gradient elution. The excitation and emission wavelengths were set at 360 and 425 nm. The 2-DG calibration curves were linear over the range of 0.63-300 µg/mL with a limit of detection of 0.5 µg/mL. The assay provided satisfactory intra-day and inter-day precision with RSD less than 9.8%, and the accuracy ranged from 86.8 to 110.0%. The HPLC method is reproducible and suitable for the quantitation of 2-DG in plasma. The method was successfully applied to characterize the pharmacokinetics profile of 2-DG in patients with advanced solid tumors. Copyright © 2011 John Wiley & Sons, Ltd.

  18. Bladder cancer detection using a peptide substrate of the 20S proteasome.

    Science.gov (United States)

    Gruba, Natalia; Wysocka, Magdalena; Brzezińska, Magdalena; Dębowski, Dawid; Sieńczyk, Marcin; Gorodkiewicz, Ewa; Guszcz, Tomasz; Czaplewski, Cezary; Rolka, Krzysztof; Lesner, Adam

    2016-08-01

    The 20S catalytic core of the human 26S proteasome can be secreted from cells, and high levels of extracellular 20S proteasome have been linked to many types of cancers and autoimmune diseases. Several diagnostic approaches have been developed that detect 20S proteasome activity in plasma, but these suffer from problems with efficiency and sensitivity. In this report, we describe the optimization and synthesis of an internally quenched fluorescent substrate of the 20S proteasome, and investigate its use as a potential diagnostic test in bladder cancer. This peptide, 2-aminobenzoic acid (ABZ)-Val-Val-Ser-Tyr-Ala-Met-Gly-Tyr(3-NO2 )-NH2 , is cleaved by the chymotrypsin 20S proteasome subunit and displays an excellent specificity constant value (9.7 × 10(5)  m(-1) ·s(-1) ) and a high kcat (8 s(-1) ). Using this peptide, we identified chymotrypsin-like proteasome activity in the majority of urine samples obtained from patients with bladder cancer, whereas the proteasome activity in urine samples from healthy volunteers was below the detection limit (0.5 pm). These findings were confirmed by an inhibitory study and immunochemistry methods. © 2016 Federation of European Biochemical Societies.

  19. Evidence for significantly enhancing reduction of Azo dyes in Escherichia coli by expressed cytoplasmic Azoreductase (AzoA) of Enterococcus faecalis.

    Science.gov (United States)

    Feng, J; Heinze, T M; Xu, H; Cerniglia, C E; Chen, H

    2010-05-01

    Although cytoplasmic azoreductases have been purified and characterized from various bacteria, little evidence demonstrating that these azoreductases are directly involved in azo dye reduction in vivo is known. In order to evaluate the contribution of the enzyme to azo dye reduction in vivo, experiments were conducted to determine the effect of a recombinant cytoplasmic azoreductase (AzoA) from Enterococcus faecalis expressed in Escherichia coli on the rate of metabolism of Methyl Red, Ponceau BS and Orange II. The intact cells that contained IPTG induced AzoA had a higher rate of dye reduction with increases of 2 (Methyl Red), 4 (Ponceau BS) and 2.6 (Orange II)-fold compared to noninduced cells, respectively. Metabolites of Methyl Red isolated from induced cultures were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid through liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) analyses. In conclusion, our data demonstrate that AzoA from Ent. faecalis is capable of increasing the reduction of azo dyes in intact E. coli cells and that cytoplasmic azoreductase is involved in bacterial dye degradation in vivo.

  20. The Uses of 2-Ethoxy-(4H-3,1-benzoxazin-4-one in the Synthesis of Some Quinazolinone Derivatives of Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Fakhry A. El-Bassiouny

    2011-07-01

    Full Text Available The behavior of 2-ethoxy-(4H-3,1-benzoxazin-4-one (1 towards nitrogen nucleo-philes, e.g. ethanolamine, aromatic amines (namely: p-toluidine, p-anisidine, p-hydroxyaniline, o-hydroxyaniline, o-bromoaniline, o-phenylenediamine, p-phenylene- diamine, o-tolidinediamine p-aminobenzoic acid, glucosamine hydrochloride,  2-amino- nicotinic acid, 1-naphthalenesulfonic acid hydrazide, n-decanoic acid hydrazide, benzoic acid hydrazide, semicarbazide, aminoacids (e.g. D,L-alanine, L-asparagine, L-arginine and derivatives of 2-aminothiodiazole has been investigated. The behavior of the benzoxazinone towards a selected sulfur nucleophile, L-cysteine, has also been discussed. Formation of an amidine salt as a reaction intermediate has been assumed. The effect of solvent in some reactions has been elucidated. The structures of all the novel quinazoline and quinazolinone derivatives, obtained by heterocyclic ring opening and ring closure were inferred by the IR, MS as well as 1H-NMR spectral analysis. Moreover, the antimicrobial potential of some of the new synthesized derivatives has been evaluated.

  1. Fabrication of an electrochemical sensor based on computationally designed molecularly imprinted polymer for the determination of mesalamine in real samples

    International Nuclear Information System (INIS)

    Torkashvand, M.; Gholivand, M.B.; Taherkhani, F.

    2015-01-01

    A novel electrochemical sensor based on mesalamine molecularly imprinted polymer (MIP) film on a glassy carbon electrode was fabricated. Density functional theory (DFT) in gas and solution phases was developed to study the intermolecular interactions in the pre-polymerization mixture and to find the suitable functional monomers in MIP preparation. On the basis of computational results, o-phenylenediamine (OP), gallic acid (GA) and p-aminobenzoic acid (ABA) were selected as functional monomers. The MIP film was cast on glassy carbon electrode by electropolymerization of solution containing ternary monomers and then followed by Ag dendrites (AgDs) with nanobranch deposition. The surface feature of the modified electrode (AgDs/MIP/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under the optimal experimental conditions, the peak current was proportional to the concentration of mesalamine ranging from 0.05 to 100 μM, with the detection limit of 0.015 μM. The proposed sensor was applied successfully for mesalamine determination in real samples. - Highlights: • The determination of MES using AgDs/MIP/GCE is reported for the first time. • The computer assisted design of terpolymer MIPs was used to screen monomers. • Theoretical results of DFT approach were in agreement with experimental results. • The sensor displayed a high selectivity for template in the presence of interferes. • The developed sensor has been applied to determine mesalamine in real samples

  2. Determination of N-glycans by high performance liquid chromatography using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as the glycosylamine labeling reagent.

    Science.gov (United States)

    Wu, Yike; Sha, Qiuyue; Du, Juan; Wang, Chang; Zhang, Liang; Liu, Bi-Feng; Lin, Yawei; Liu, Xin

    2018-02-02

    Robust, efficient identification and accurate quantification of N-glycans are of great significance in N-glycomics analysis. Here, a simple and rapid derivatization method, based on the combination of microwave-assisted deglycosylation and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) labeling, was developed for the analysis of N-glycan by high performance liquid chromatography with fluorescence detection (HPLC-FLD). After optimizing various parameters affecting deglycosylation and derivatization by RNase B, the time for N-glycan labeling was shortened to 50 min with ∼10-fold enhancement in detection sensitivity comparing to conventional 2-aminobenzoic acid (2-AA) labeling method. Additionally, the method showed good linearity (correlation coefficients > 0.991) and reproducibility (RSD < 8.7%). These advantages of the proposed method were further validated by the analysis of complex samples, including fetuin and human serum. Investigation of serum N-glycome for preliminary diagnosis of human lung cancer was conducted, where significant changes of several N-glycans corresponding to core-fucosylated, mono- and disialylated glycans have been evidenced by a series of statistical analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Synthesis and Spectral Characterization of Antifungal Sensitive Schiff Base Transition Metal Complexes

    Science.gov (United States)

    Sakthivel, A.; Rajasekaran, K.

    2007-01-01

    New N2O2 donor type Schiff base has been designed and synthesized by condensing acetoacetanilido-4-aminoantipyrine with 2-aminobenzoic acid in ethanol. Solid metal complexes of the Schiff base with Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar conduction, fast atom bombardment (FAB) mass, IR, UV-Vis, and 1H NMR spectral studies. The data show that the complexes have the composition of ML type. The UV-Vis. and magnetic susceptibility data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The in vitro antifungal activities of the compounds were tested against fungi such as Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer, Candida albicans, Rhizoctonia bataicola and Trichoderma harizanum. All the metal complexes showed stronger antifungal activities than the free ligand. The minimum inhibitory concentrations (MIC) of the metal complexes were found in the range of 10~31 µg/ml. PMID:24015086

  4. [Improvement of local lymph node assay for cosmetics safety evaluation].

    Science.gov (United States)

    Liu, Zhen; Liu, Junping; Wang, Fei; Xu, Guifeng; Hou, Juan; Wan, Xuying; Zhang, Tianbao

    2009-09-01

    To improve the local lymph node assay (LLNA) as an alternative method to detect chemicals for both sensitization and irritation. The following chemicals: one negative control: 4-Aminobenzoic Acid, three sensitizers: 2,4-dinitrochlorobenzene (DNCB), Hexyl cinnamic aldehyde (HCA), 2-Aminophenol (2-APC) and two irritations: potassium hydroxide (KOH), sodium lauryl sulphate (SLS) were selected. According to the normal LLNA, groups of female Balb/c mice were treated with test solutions. The thickness of each ear was measured and each auricle was weighed. On the sixth day, the bilateral draining auricular lymph nodes were excised and weighed. The single cell suspensions were prepared, the lymphocyte were counted and the proliferations of lymph cells were detected by cell counting kit-8 (CCK-8). Significant increase in ear thickness and weight were found in groups of KOH, SLS and DNCB (above 0.5%) (P LLNA using auricle thickness and weighing as observed markers for irritation, and using lymph nodes weighing and proliferation of lymphocyte as observed markers for sensitization, could evaluate both sensitization and irritation at the same time.

  5. Effect of prolonged exposure to low antigen concentration for sensitization

    International Nuclear Information System (INIS)

    Och, Francois M.M. van; Vandebriel, Rob J.; Jong, Wim H. de; Loveren, Henk van

    2003-01-01

    The local lymph node assay (LLNA) is an assay in mice to identify potential allergens. Compounds that do not induce a stimulation index (SI)≥3 are not considered sensitizers. Of the chemicals that do, the SI of 3 is used as a benchmark, and indicates the sensitizing potency of a chemical. Compared to the exposure duration of the LLNA (3 days), real life exposure often lasts for months or years. We therefore investigated whether prolonged exposure to sensitizers at concentrations that do not induce a SI≥3 in the LLNA, were able to surpass this threshold. Mice were treated for 2 months at 7-day intervals with a range of concentrations of the known allergens ethyl-p-aminobenzoate (benzocaine, BENZ), 2,4-dinitrochlorobenzene (DNCB), and tetramethyl thiuram disulfide (TMTD). Both proliferative activity and cytokine production were established at day 60. Neither BENZ nor TMTD showed a significant increase in the proliferation rate compared to vehicle controls. Only DNCB at concentrations originally above the EC 3 a significant increase in proliferation was seen after prolonged exposure. No significant effect on IFN-γ and IL-4 production was observed for all three compounds compared. These findings indicate that for classification of sensitizers the shorter exposure period employed in the standard LLNA is sufficient, and longer periods of exposure have no bearing on this classification

  6. Chromatographic determination of nanomolar cyanate concentrations in estuarine and sea waters by precolumn fluorescence derivatization.

    Science.gov (United States)

    Widner, Brittany; Mulholland, Margaret R; Mopper, Kenneth

    2013-07-16

    Recent studies suggest that cyanate (OCN(-)) is a potentially important source of reduced nitrogen (N) available to support the growth of aquatic microbes and, thus, may play a role in aquatic N cycling. However, aquatic OCN(-) distributions have not been previously described because of the lack of a suitable assay for measuring OCN(-) concentrations in natural waters. Previous methods were designed to quantify OCN(-) in aqueous samples with much higher reduced N concentrations (micromolar levels) than those likely to be found in natural waters (nanomolar levels). We have developed a method to quantify OCN(-) in dilute, saline environments. In the method described here, OCN(-) in aqueous solution reacts with 2-aminobenzoic acid to produce a highly fluorescent derivative, 2,4-quinazolinedione, which is then quantified using high performance liquid chromatography. Derivatization conditions were optimized to simultaneously minimize the reagent blank and maximize 2,4-quinazolinedione formation (>90% reaction yield) in estuarine and seawater matrices. A limit of detection (LOD) of 0.4 nM was achieved with only minor matrix effects. We applied this method to measure OCN(-) concentrations in estuarine and seawater samples from the Chesapeake Bay and coastal waters from the mid-Atlantic region. OCN(-) concentrations ranged from 0.9 to 41 nM. We determined that OCN(-) concentrations were stable in 0.2 μm filtered seawater samples stored at -80 °C for up to nine months.

  7. Development and validation of a liquid chromatography method for the simultaneous determination of eight water-soluble vitamins in multivitamin formulations and human urine.

    Science.gov (United States)

    Patil, Suyog S; Srivastava, Ashwini K

    2013-01-01

    A simple, precise, and rapid RPLC method has been developed without incorporation of any ion-pair reagent for the simultaneous determination of vitamin C (C) and seven B-complex vitamins, viz, thiamine hydrochloride (B1), pyridoxine hydrochloride (B6), nicotinamide (B3), cyanocobalamine (B12), folic acid, riboflavin (B2), and 4-aminobenzoic acid (Bx). Separations were achieved within 12.0 min at 30 degrees C by gradient elution on an RP C18 column using a mobile phase consisting of a mixture of 15 mM ammonium formate buffer and 0.1% triethylamine adjusted to pH 4.0 with formic acid and acetonitrile. Simultaneous UV detection was performed at 275 and 360 nm. The method was validated for system suitability, LOD, LOQ, linearity, precision, accuracy, specificity, and robustness in accordance with International Conference on Harmonization guidelines. The developed method was implemented successfully for determination of the aforementioned vitamins in pharmaceutical formulations containing an individual vitamin, in their multivitamin combinations, and in human urine samples. The calibration curves for all analytes showed good linearity, with coefficients of correlation higher than 0.9998. Accuracy, intraday repeatability (n = 6), and interday repeatability (n = 7) were found to be satisfactory.

  8. High-throughput metagenomic analysis of petroleum-contaminated soil microbiome reveals the versatility in xenobiotic aromatics metabolism.

    Science.gov (United States)

    Bao, Yun-Juan; Xu, Zixiang; Li, Yang; Yao, Zhi; Sun, Jibin; Song, Hui

    2017-06-01

    The soil with petroleum contamination is one of the most studied soil ecosystems due to its rich microorganisms for hydrocarbon degradation and broad applications in bioremediation. However, our understanding of the genomic properties and functional traits of the soil microbiome is limited. In this study, we used high-throughput metagenomic sequencing to comprehensively study the microbial community from petroleum-contaminated soils near Tianjin Dagang oilfield in eastern China. The analysis reveals that the soil metagenome is characterized by high level of community diversity and metabolic versatility. The metageome community is predominated by γ-Proteobacteria and α-Proteobacteria, which are key players for petroleum hydrocarbon degradation. The functional study demonstrates over-represented enzyme groups and pathways involved in degradation of a broad set of xenobiotic aromatic compounds, including toluene, xylene, chlorobenzoate, aminobenzoate, DDT, methylnaphthalene, and bisphenol. A composite metabolic network is proposed for the identified pathways, thus consolidating our identification of the pathways. The overall data demonstrated the great potential of the studied soil microbiome in the xenobiotic aromatics degradation. The results not only establish a rich reservoir for novel enzyme discovery but also provide putative applications in bioremediation. Copyright © 2016. Published by Elsevier B.V.

  9. Morphological structure of Gluconacetobacter xylinus cellulose and cellulose-based organic-inorganic composite materials

    Science.gov (United States)

    Smyslov, R. Yu; Ezdakova, K. V.; Kopitsa, G. P.; Khripunov, A. K.; Bugrov, A. N.; Tkachenko, A. A.; Angelov, B.; Pipich, V.; Szekely, N. K.; Baranchikov, A. E.; Latysheva, E.; Chetverikov, Yu O.; Haramus, V.

    2017-05-01

    Scanning electron microscopy, ultra-small-angle neutron scattering (USANS), small-angle neutron and X-ray scattering (SANS and SAXS), as well as low-temperature nitrogen adsorption, were used in the studies of micro- and mesostructure of polymer matrix prepared from air-dry preliminarily disintegrated cellulose nano-gel film (synthesized by Gluconacetobacter xylinus) and the composites based on this bacterial cellulose. The composites included ZrO2 nanoparticles, Tb3+ in the form of low molecular weight salt and of metal-polymer complex with poly(vinylpyrrolydone)-poly(methacryloyl-o-aminobenzoic acid) copolymer. The combined analysis of the data obtained allowed revealing three levels of fractal organization in mesostructure of G. xylinus cellulose and its composites. It was shown that both the composition and an aggregation state of dopants have a significant impact on the structural characteristics of the organic-inorganic composites. The composites containing Tb3+ ions demonstrate efficient luminescence; its intensity is an order of magnitude higher in the case of the composites with the metal-polymer complex. It was found that there is the optimal content of ZrO2 nanoparticles in composites resulting in increased Tb3+ luminescence.

  10. The cholesteryl octanoate breath test: a new procedure for detection of pancreatic insufficiency in the rat.

    Science.gov (United States)

    Mundlos, S; Rhodes, J B; Hofmann, A F

    1987-09-01

    A breath test for the detection of pancreatic insufficiency was developed and tested in rats. The test features the hydrophobic molecule cholesteryl-1-14C-octanoate, which liberates 14C-octanoic acid when hydrolyzed by carboxyl ester lipase (cholesterol esterase). The 14C-octanoate is absorbed passively and rapidly metabolized to 14CO2, which is excreted in expired air. The compound was administered as an emulsion of cholesteryl octanoate, triglyceride, and lecithin to rats with mild pancreatic insufficiency induced by injecting the pancreatic duct with zein. The animals had exocrine pancreatic hypofunction based on the enzyme content of pancreas at autopsy. Amylase was reduced by 97.1 +/- 1.4%, whereas chymotrypsin was reduced by 73 +/- 14%. The p-aminobenzoic acid test was abnormal at 1 wk (21.68 +/- 8.4%), but become normal at 3 months (72.08 +/- 5.8%) after zein injection. Despite this, the animals gained weight and absorbed fat normally. The 14CO2 excretion rate in the 110-min interval after feeding was significantly reduced to 60% of sham-operated animals. Peak 14CO2 collections 20 min after feeding were reduced by 75 +/- 11%. 14CO2 output was completely normalized by administration of pancreatin prior to the test meal. The results suggest that a sensitive, noninvasive method for detecting deficiency of pancreatic carboxyl ester lipase (cholesterol esterase) secretion in the rat has been developed.

  11. Investigation of the luminescent properties of terbium-anthranilate complexes and application to the determination of anthranilic acid derivatives in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, N.; Georges, J

    2003-01-10

    The luminescent properties of terbium complexes with furosemide (FR), flufenamic (FF) acid, tolfenamic (TF) acid and mefenamic (MF) acid have been investigated in aqueous solutions. For all four compounds, complexation occurs when the carboxylic acid of the aminobenzoic group is dissociated and is greatly favoured in the presence of trioctylphosphine oxide as co-ligand and Triton X-100 as surfactant. Under optimum conditions, luminescence of the lanthanide ion is efficiently sensitised and the lifetime of the {sup 5}D{sub 4} resonance level of terbium in the complex is ranging between 1 and 1.9 ms, against 0.4 ms for the aqua ion. The sensitivity of the method for the determination of anthranilic acid derivatives is improved by one to two orders of magnitude with respect to that achieved using native fluorescence or terbium-sensitised luminescence in methanol. The limits of detection are 2x10{sup -10}, 5x10{sup -10} and 2x10{sup -9} mol l{sup -1} for flufenamic acid, furosemide and tolfenamic acid, and mefenamic acid, respectively, with within-run RSD values of less than 1%. The method has been applied to the determination of flufenamic acid in spiked calf sera with and without sample pretreatment. Depending on the method and the analyte concentration, the recovery was ranging between 83 and 113% and the lowest concentration attainable in serum samples was close to 1x10{sup -7} mol l{sup -1}.

  12. Main metabolites of 1-(2-chloroethyl)-3-[1'-(5'-p-nitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea and 1-(2-chloroethyl)-3-(2',3', 4'-tri-O-acetyl-alpha, beta-D-ribopyranosyl)-1-nitrosourea in rats

    International Nuclear Information System (INIS)

    Madelmont, J.C.; Moreau, M.F.; Godeneche, D.; Duprat, J.; Plagne, R.; Meyniel, G.

    1982-01-01

    The metabolism of two glycosylnitrosoureas, 1-(2-chloroethyl)-3-[1'-(5'-p-nitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea (RFCNU) and 1-(2-chloroethyl)-3-(2',3',4'-tri-O-acetyl-alpha, beta-D-ribopyranosyl)-1-nitrosourea (RPCNU), has been investigated in the rat. With the label on the carboxyl moiety of RFCNU, we have shown that hydrolysis of the 4-nitrobenzoyl ester occurred to a large extent in vivo; 4-nitrobenzoic acid and its glucuronide were the major urinary metabolites. Two other minor metabolites and their glucuronides were identified as 4-aminobenzoic acid and 4-acetamidobenzoic acid. With the label on the chloroethyl moieties of RFCNU and RPCNU, we have shown that chloroethanol was a major degradation product of this alkylating part of the molecule. The concentration of chloroethanol in plasma vs. time has been determined. In urine, four metabolites derived from alkylated glutathione, namely thiodiacetic acid and its sulfoxide, N-acetylcarboxymethylcysteine, and N-acetylhydroxyethylcysteine, have been identified

  13. Novel nanocomposite Kevlar fabric membranes: Fabrication characterization, and performance in oil/water separation

    Science.gov (United States)

    Karimnezhad, Hanieh; Rajabi, Laleh; Salehi, Ehsan; Derakhshan, Ali Ashraf; Azimi, Sara

    2014-02-01

    Nanocomposite membranes with hydrophilic surface were fabricated for separation of oil (n-hexane) from oil/water emulsion. Three different nanomaterials namely, para-aminobenzoate alumoxane (PAB-A), boehmite-epoxide and polycitrate alumoxane (PC-A) were coated on the Kevlar fabric (support), according to a three-step dip-coating protocol. FTIR, SEM, TEM, UV/vis spectrophotometer, and wettability analyses were used to characterize the composite membranes. The three coating layers interacted chemically with one another and also physically with the Kevlar fabric. Water uptake measurements indicated that the membrane is a hydrophilic one. SEM and TEM analyses showed the smooth surface of the composite membrane and three-dimensional dendrimeric hyper-branched structure of (PC-A), respectively. A dead-end filtration setup was applied to test the membranes performance under natural gravity force. Effect of pH as an important variable affecting separation process was investigated with the neutral pH provided the optimum condition for the separation. Oil rejection and permeate fluxes were also monitored. The optimum flux and rejection obtained, were 7392 (Lm-2 h-1) and 89.06% at pH 7, respectively. Fouling occurred as a gel layer on the membrane surface. The deposited oil droplets on the surface of the membrane were successfully washed away with satisfactory permeate flux recovery (FRR = 88.88% at neutral pH), using hot distilled water and acidic solution as eluents.

  14. Fabrication of Hydrophobic Membrane for the Separation of n-Hexane/Water Mixture Using Novel Oleophilic Nanoparticle and Kevlar Fabric, as a Superior Support

    Directory of Open Access Journals (Sweden)

    Hanieh Karimnezhad

    2017-07-01

    Full Text Available The fabrication of functionalized membranes with hydrophobic/oleophilic surfaces for the elimination of n-hexane from water using para-aminobenzoate alumoxane, boehmite-epoxide and a novel nanoparticle, i.e., Stearate Alumoxane by a simple coating technique, is reported here. FTIR was used to characterize nanoparticles. SEM and contact angle measurement analyses were used to identify the nanocomposite membranes. The concentrations of oil in permeate and retentate were measured by UV/vis spectrophotometer. The morphology of Stearate alumoxane nanoparticles was investigated by means of SEM images. The composed film of nanoparticles on the Kevlar fabric was hydrophobic with water contact angle of ~ 145° and oleophilic with oil contact angle of ~ 0º. In addition, the membranes retained stable hydrophobicity and high separation efficiency even after employing for 6 times. Applying these properties, a setup was considered using the functionalized Kevlar fabric to separate oil through down to a collector and leave water drops. Our batch filtration system was exclusively gravity-driven. The achieved separation system can separate the oily water mixture (with the concentration of 20 % (v/v n-hexane in water, effectively with a separation efficiency of 84%.

  15. Grafting of activated carbon cloths for selective adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Gineys, M.; Benoit, R.; Cohaut, N.; Béguin, F.; Delpeux-Ouldriane, S., E-mail: delpeux@cnrs-orleans.fr

    2016-05-01

    Graphical abstract: - Highlights: • A controlled grafting of carboxylic functions on activated carbon fibers. • The carbon material nanotextural properties preservation after grafting. • An identification of the grafting mechanism through ToF SIMS analysis. • A chemical mapping of the grafted surface using ToF SIMS technique and imaging. - Abstract: Chemical functionalization of an activated carbon cloth with 3-aminophthalic acid and 4-aminobenzoic acid groups by the in situ formation of the corresponding diazonium salt in aqueous acidic solution is reported. The nature and amount of selected functions on an activated carbon surface, in particular the grafted density, were determined by potentiometric titration, elemental analysis and X-ray photoelectron spectroscopy (XPS). The nanotextural properties of the modified carbon were explored by gas adsorption. Functionalized activated carbon cloth was obtained at a discrete grafting level while preserving interesting textural properties and a large porous volume. Finally, the grafting homogeneity of the carbon surface and the nature of the chemical bonding were investigated using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) technique.

  16. Gold nanostar-enhanced surface plasmon resonance biosensor based on carboxyl-functionalized graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiong; Sun, Ying; Ma, Pinyi; Zhang, Di; Li, Shuo; Wang, Xinghua; Song, Daqian, E-mail: songdq@jlu.edu.cn

    2016-03-24

    A new high-sensitivity surface plasmon resonance (SPR) biosensor based on biofunctional gold nanostars (AuNSs) and carboxyl-functionalized graphene oxide (cGO) sheets was described. Compared with spherical gold nanoparticles (AuNPs), the anisotropic structure of AuNSs, which concentrates the electric charge density on its sharp tips, could enhance the local electromagnetic field and the electronic coupling effect significantly. cGO was obtained by a diazonium reaction of graphene oxide (GO) with 4-aminobenzoic acid. Compared with GO, cGO could immobilize more antibodies due to the abundant carboxylic groups on its surface. Testing results show that there are fairly large improvements in the analytical performance of the SPR biosensor using cGO/AuNSs-antigen conjugate, and the detection limit of the proposed biosensor is 0.0375 μg mL{sup −1}, which is 32 times lower than that of graphene oxide-based biosensor. - Highlights: • A sensitive and versatile SPR biosensor was constructed for detection of pig IgG. • Biofunctional gold nanostars were used to amplify the response signals. • The strategy employed carboxyl-functionalized graphene oxide as biosensing substrate. • The detection limit of the proposed biosensor is 32 times lower than that of graphene oxide-based biosensor.

  17. Analysis of glycoprotein-derived oligosaccharides in glycoproteins detected on two-dimensional gel by capillary electrophoresis using on-line concentration method.

    Science.gov (United States)

    Kamoda, Satoru; Nakanishi, Yasuharu; Kinoshita, Mitsuhiro; Ishikawa, Rika; Kakehi, Kazuaki

    2006-02-17

    Capillary electrophoresis (CE) is an effective tool to analyze carbohydrate mixture derived from glycoproteins with high resolution. However, CE has a disadvantage that a few nanoliters of a sample solution are injected to a narrow capillary. Therefore, we have to prepare a sample solution of high concentration for CE analysis. In the present study, we applied head column field-amplified sample stacking method to the analysis of N-linked oligosaccharides derived from glycoprotein separated by two-dimensional gel electrophoresis. Model studies demonstrated that we achieved 60-360 times concentration effect on the analysis of carbohydrate chains labeled with 3-aminobenzoic acid (3-AA). The method was applied to the analysis of N-linked oligosaccharides from glycoproteins separated and detected on PAGE gel. Heterogeneity of alpha1-acid glycoprotein (AGP), i.e. glycoforms, was examined by 2D-PAGE and N-linked oligosaccharides were released by in-gel digestion with PNGase F. The released oligosaccharides were derivatized with 3-AA and analyzed by CE. The results showed that glycoforms having lower pI values contained a larger amount of tetra- and tri-antennary oligosaccharides. In contrast, glycoforms having higher pI values contained bi-antennary oligosaccharides abundantly. The result clearly indicated that the spot of a glycoprotein glycoform detected by Coomassie brilliant blue staining on 2D-PAGE gel is sufficient for quantitative profiling of oligosaccharides.

  18. Effects of pig slurry on the sorption of sulfonamide antibiotics in soil.

    Science.gov (United States)

    Thiele-Bruhn, S; Aust, M O

    2004-07-01

    Sorption of p-aminobenzoic acid (pABA) and five sulfonamide antibiotics to loess Chernozem topsoil amended with varied additions of pig slurry was investigated in batch trials. In unfertilized soil, partition coefficients (Kd) of sulfonamides ranged from 0.3 to 2.0. Strong sorption nonlinearity (1/n = 0.5 to 0.8) was best fitted by the Freundlich isotherm (R2 = 0.7 to 1.0) and was indicative for specific sorption mechanisms. Adsorption to pig slurry was much stronger, and nondesorbable portions were increased compared with soil. However, in a mixture of soil and slurry (50:1 w/w), sorption of the antibiotics was significantly decreased at a lower concentration range of pABA and the sulfonamides. This was attributed to competitive adsorption of dissolved organic matter (DOM) constituents from manure. An increase in pig slurry amendment resulted in increased total organic matter, DOM concentration, and ionic strength, but pH decreased. As a result, the nonadsorbed portions of pABA, sulfanilamide, and sulfadiazine (logD(ow) 0.1)--remained nearly constant in the presence of increased manure input. The pH changes caused by manure amendment strongly affected ionisation status of the latter compounds, thus resulting in increased adsorption, which compensated the mobilizing effect of DOM. It is suggested that the effect of manure be considered in test methods to determine the soil retention of pharmaceutical substances.

  19. Influence of porous texture and surface chemistry on the CO₂ adsorption capacity of porous carbons: acidic and basic site interactions.

    Science.gov (United States)

    Sánchez-Sánchez, Angela; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M D

    2014-12-10

    Doped porous carbons exhibiting highly developed porosity and rich surface chemistry have been prepared and subsequently applied to clarify the influence of both factors on carbon dioxide capture. Nanocasting was selected as synthetic route, in which a polyaramide precursor (3-aminobenzoic acid) was thermally polymerized inside the porosity of an SBA-15 template in the presence of different H3PO4 concentrations. The surface chemistry and the porous texture of the carbons could be easily modulated by varying the H3PO4 concentration and carbonization temperature. Porous texture was found to be the determinant factor on carbon dioxide adsorption at 0 °C, while surface chemistry played an important role at higher adsorption temperatures. We proved that nitrogen functionalities acted as basic sites and oxygen and phosphorus groups as acidic ones toward adsorption of CO2 molecules. Among the nitrogen functional groups, pyrrolic groups exhibited the highest influence, while the positive effect of pyridinic and quaternary functionalities was smaller. Finally, some of these N-doped carbons exhibit CO2 heats of adsorption higher than 42 kJ/mol, which make them excellent candidates for CO2 capture.

  20. Degradation of phenol via phenylphosphate and carboxylation to 4-hydroxybenzoate by a newly isolated strain of the sulfate-reducing bacterium Desulfobacterium anilini.

    Science.gov (United States)

    Ahn, Young-Beom; Chae, Jong-Chan; Zylstra, Gerben J; Häggblom, Max M

    2009-07-01

    A sulfate-reducing phenol-degrading bacterium, strain AK1, was isolated from a 2-bromophenol-utilizing sulfidogenic estuarine sediment enrichment culture. On the basis of phylogenetic analysis of the 16S rRNA gene and DNA homology, strain AK1 is most closely related to Desulfobacterium anilini strain Ani1 (= DSM 4660(T)). In addition to phenol, this organism degrades a variety of other aromatic compounds, including benzoate, 2-hydroxybenzoate, 4-hydroxybenzoate, 4-hydroxyphenylacetate, 2-aminobenzoate, 2-fluorophenol, and 2-fluorobenzoate, but it does not degrade aniline, 3-hydroxybenzoate, 4-cyanophenol, 2,4-dihydroxybenzoate, monohalogenated phenols, or monohalogenated benzoates. Growth with sulfate as an electron acceptor occurred with acetate and pyruvate but not with citrate, propionate, butyrate, lactate, glucose, or succinate. Strain AK1 is able to use sulfate, sulfite, and thiosulfate as electron acceptors. A putative phenylphosphate synthase gene responsible for anaerobic phenol degradation was identified in strain AK1. In phenol-grown cultures inducible expression of the ppsA gene was verified by reverse transcriptase PCR, and 4-hydroxybenzoate was detected as an intermediate. These results suggest that the pathway for anaerobic degradation of phenol in D. anilini strain AK1 proceeds via phosphorylation of phenol to phenylphosphate, followed by carboxylation to 4-hydroxybenzoate. The details concerning such reaction pathways in sulfidogenic bacteria have not been characterized previously.

  1. Revised mechanism of Boyland-Sims oxidation.

    Science.gov (United States)

    Marjanović, Budimir; Juranić, Ivan; Cirić-Marjanović, Gordana

    2011-04-21

    New computational insights into the mechanism of the Boyland-Sims oxidation of arylamines with peroxydisulfate (S(2)O(8)(2-)) in an alkaline aqueous solution are presented. The key role of arylnitrenium cations, in the case of primary and secondary arylamines, and arylamine dications and immonium cations, in the case of tertiary arylamines, in the formation of corresponding o-aminoaryl sulfates, as prevalent soluble products, and oligoarylamines, as prevalent insoluble products, is proposed on the basis of the AM1 and RM1 computational study of the Boyland-Sims oxidation of aniline, ring-substituted (2-methylaniline, 3-methylaniline, 4-methylaniline, 2,6-dimethylaniline, anthranilic acid, 4-aminobenzoic acid, sulfanilic acid, sulfanilamide, 4-phenylaniline, 4-bromoaniline, 3-chloroaniline, and 2-nitroaniline) and N-substituted anilines (N-methylaniline, diphenylamine, and N,N-dimethylaniline). Arylnitrenium cations and sulfate anions (SO(4)(2-)) are generated by rate-determining two-electron oxidation of primary and secondary arylamines with S(2)O(8)(2-), while arylamine dications/immonium cations and SO(4)(2-) are initially formed by two-electron oxidation of tertiary arylamines with S(2)O(8)(2-). The subsequent regioselectivity-determining reaction of arylnitrenium cations/arylamine dications/immonium cations and SO(4)(2-), within the solvent cage, is computationally found to lead to the prevalent formation of o-aminoaryl sulfates. The formation of insoluble precipitates during the Boyland-Sims oxidation of arylamines was also computationally studied.

  2. Mathematical Evaluation of the Amino Acid and Polyphenol Content and Antioxidant Activities of Fruits from Different Apricot Cultivars

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2011-09-01

    Full Text Available Functional foods are of interest because of their significant effects on human health, which can be connected with the presence of some biologically important compounds. In this study, we carried out complex analysis of 239 apricot cultivars (Prunus armeniaca L. cultivated in Lednice (climatic area T4, South Moravia, Czech Republic. Almost all previously published studies have focused only on analysis of certain parameters. However, we focused on detection both primary and secondary metabolites in a selection of apricot cultivars with respect to their biological activity. The contents of thirteen biogenic alpha-L-amino acids (arginine, asparagine, isoleucine, lysine, serine, threonine, valine, leucine, phenylalanine, tryptophan, tyrosine, proline and alanine were determined using ion exchange chromatography with UV-Vis spectrometry detection. Profile of polyphenols, measured as content of ten polyphenols with significant antioxidant properties (gallic acid, procatechinic acid, p-aminobenzoic acid, chlorogenic acid, caffeic acid, vanillin, p-coumaric acid, rutin, ferrulic acid and quercetrin, was determined by high performance liquid chromatography with spectrometric/electrochemical detection. Moreover, content of total phenolics was determined spectrophotometrically using the Folin-Ciocalteu method. Antioxidant activity was determined using five independent spectrophotometric methods: DPPH assay, DMPD method, ABTS method, FRAP and Free Radicals methods. Considering the complexity of the obtained data, they were processed and correlated using bioinformatics techniques (cluster analysis, principal component analysis. The studied apricot cultivars were clustered according to their common biochemical properties, which has not been done before. The observed similarities and differences were discussed.

  3. Photocatalytic degradation of sunscreen active ingredients mediated by nanostructured materials

    Science.gov (United States)

    Soto-Vazquez, Loraine

    Water scarcity and pollution are environmental issues with terrible consequences. In recent years several pharmaceutical and personal care products, such as sunscreen active ingredients, have been detected in different water matrices. Its recalcitrant behavior in the environment has caused controversies and generated countless questions about its safety. During this research, we employed an advanced oxidation process (photocatalysis) to degrade sunscreen active ingredients. For this study, we used a 3x3 system, evaluating three photocatalysts and three different contaminants. From the three catalysts employed, two of them were synthesized. ZnO nanoparticles were obtained using zinc acetate dihydrated as the precursor, and TiO2 nanowires were synthesized from titanium tetrachloride precursor. The third catalyst employed (namely, P25) was obtained commercially. The synthesized photocatalysts were characterized in terms of the morphology, elemental composition, crystalline structure, elemental oxidation states, vibrational modes and surface area, using SEM-EDS, XRD, XPS, Raman spectroscopy and BET measurements, respectively. The photocatalysts were employed during the study of the degradation of p-aminobenzoic acid, phenylbenzimidazole sulfonic acid, and benzophenone-4. In all the cases, at least 50% degradation was achieved. P25 showed degradation efficiencies above 90%, and from the nine systems, 7 of them degraded at least 86%.

  4. Pancreatic endocrine and exocrine function and salivary gland function in autoimmune pancreatitis before and after steroid therapy.

    Science.gov (United States)

    Kamisawa, Terumi; Egawa, Naoto; Inokuma, Shigeko; Tsuruta, Kouji; Okamoto, Atsutake; Kamata, Noriko; Nakamura, Teruo; Matsukawa, Masakatsu

    2003-10-01

    Autoimmune pancreatitis (AIP) is a distinct clinical entity in which an autoimmune mechanism may be involved in pathogenesis. To investigate salivary gland function in addition to pancreatic endocrine and exocrine function in patients with AIP, and to determine changes occurring after steroid therapy. Fasting serum glucose levels, oral glucose tolerance tests or glycosylated hemoglobin values were examined in 19 patients with AIP. N-benzoyl-L-tyrosyl-p-aminobenzoic acid excretion test, sialochemistry and parotid gland scintigraphy were performed in 8 patients. Eight patients had evidence of DM. Steroid therapy subsequently improved insulin secretion and glycemic control in 3 of 5 patients treated. Pancreatic exocrine function was reduced in 88% of patients. Impaired pancreatic exocrine function improved after steroid therapy in 3 of 6 patients treated. The 3 patients also showed treatment-related improvement in endocrine function. Concentration of beta2-microglobulin in saliva was significantly raised in patients with AIP compared with controls (P gland dysfunction improved after steroid therapy in all 5 patients treated. Pancreatic endocrine and exocrine and salivary gland function were frequently impaired in patients with AIP, and steroid therapy was occasionally effective for these dysfunctions.

  5. Cocrystals of Hydrochlorothiazide: Solubility and Diffusion/Permeability Enhancements through Drug-Coformer Interactions.

    Science.gov (United States)

    Sanphui, Palash; Devi, V Kusum; Clara, Deepa; Malviya, Nidhi; Ganguly, Somnath; Desiraju, Gautam R

    2015-05-04

    Hydrochlorothiazide (HCT) is a diuretic and a BCS class IV drug with low solubility and low permeability, exhibiting poor oral absorption. The present study attempts to improve the physicochemical properties of the drug using a crystal engineering approach with cocrystals. Such multicomponent crystals of HCT with nicotinic acid (NIC), nicotinamide (NCT), 4-aminobenzoic acid (PABA), succinamide (SAM), and resorcinol (RES) were prepared using liquid-assisted grinding, and their solubilities in pH 7.4 buffer were evaluated. Diffusion and membrane permeability were studied using a Franz diffusion cell. Except for the SAM and NIC cocrystals, all other binary systems exhibited improved solubility. All of the cocrystals showed improved diffusion/membrane permeability compared to that of HCT with the exception of the SAM cocrystal. When the solubility was high, as in the case of PABA, NCT, and RES cocrystals, the flux/permeability dropped slightly. This is in agreement with the expected interplay between solubility and permeability. Improved solubility/permeability is attributed to new drug-coformer interactions. Cocrystals of SAM, however, showed poor solubility and flux. This cocrystal contains a primary sulfonamide dimer synthon similar to that of HCT polymorphs, which may be a reason for its unusual behavior. Hirshfeld surface analysis was carried out in all cases to determine whether a correlation exists between cocrystal permeability and drug-coformer interactions.

  6. Crystal and molecular structures of sixteen charge-assisted hydrogen bond-mediated diisopropylammonium salts from different carboxylic acids

    Science.gov (United States)

    Lin, Zhihao; Hu, Kaikai; Jin, Shouwen; Ding, Aihua; Wang, Yining; Dong, Lingfeng; Gao, Xingjun; Wang, Daqi

    2017-10-01

    Cocrystallization of the commonly available organic amine, diisopropylamine, with a series of carboxylic acids gave a total of sixteen molecular salts with the compositions: diisopropylaminium 2-methyl-2-phenoxypropanate [(Hdpa)+ · (mpa-), mpa- = 2-methyl-2-phenoxypropanoate] (1), diisopropylaminium 2-methyl-2-(naphthalen-2-yloxy)-propionate [(Hdpa)+ · (npa-), npa- = 2-methyl-2-(naphthalen-2-yloxy)-propionate] (2), diisopropylaminium indole-3-acetate [(Hdpa)+ · (iaa-), iaa- = indole-3-acetate] (3), diisopropylaminium 4-chlorophenoxyacetate [(Hdpa)+ · (cpa-), cpa- = 4-chlorophenoxyacetate] (4), diisopropylaminium 2,4-dichlorophenoxyacetate [(Hdpa)+ · (dcpa-), dcpa- = 2,4-dichlorophenoxyacetate] (5), diisopropylaminium 4-hydroxybenzoate [(Hdpa)+ · (hba-), hba- = 4-hydroxybenzoate] (6), diisopropylaminium 4-aminobenzoate [(Hdpa)+ · (aba-), aba- = 4-aminobenzoate] (7), tetra(diisopropylaminium) tetra(1-hydroxy-2-naphthoate) trihydrate [(Hdpa)44+ · (2-hnpa)44- · 3H2O, 2-hnpa = 1-hydroxy-2-naphthoate] (8), diisopropylaminium 2-hydroxy-3-naphthoate [(Hdpa)+ · (3-hnpa-), 3-hnpa- = 2-hydroxy-3-naphthoate] (9), diisopropylaminium 5-bromosalicylate [(Hdpa)+ · (bsa-), bsa- = 5-bromosalicylate] (10), diisopropylaminium 3,5-dinitrobenzoate [(Hdpa)+ · (dna-), dna- = 3,5-dinitrobenzoate] (11), diisopropylaminium 3,5-dinitrosalicylate [(Hdpa)+ · (3,5-dns-), 3,5-dns- = 3,5-dinitrosalicylate] (12), tetra(diisopropylaminium) bis(m-phthalate) monohydrate [(Hdpa+)4 · (mpta2-)2 · H2O, mpta2- = m-phthalate] (13), bis(diisopropylaminium) dihydrogen 1,2,3,4-butane tetracarboxylate [(Hdpa+)2 · (H2Bta2-), H2Bta2- = dihydrogen 1,2,3,4-butane tetracarboxylate] (14), bis(diisopropylaminium) mucate [(Hdpa+)2 · (muc2-), muc2- = mucate] (15), and diisopropylaminium hydrogen 1,2-phenylenediacetate [(Hdpa) · (Hpda-), Hpda- = hydrogen 1,2-phenylenediacetate] (16). The sixteen salts have been characterised by XRD technique, IR, and elemental analysis, and the melting points of all the

  7. Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release.

    Directory of Open Access Journals (Sweden)

    Gurinder K Vinner

    Full Text Available The prevalence of pathogenic bacteria acquiring multidrug antibiotic resistance is a global health threat to mankind. This has motivated a renewed interest in developing alternatives to conventional antibiotics including bacteriophages (viruses as therapeutic agents. The bacterium Clostridium difficile causes colon infection and is particularly difficult to treat with existing antibiotics; phage therapy may offer a viable alternative. The punitive environment within the gastrointestinal tract can inactivate orally delivered phages. C. difficile specific bacteriophage, myovirus CDKM9 was encapsulated in a pH responsive polymer (Eudragit® S100 with and without alginate using a flow focussing glass microcapillary device. Highly monodispersed core-shell microparticles containing phages trapped within the particle core were produced by in situ polymer curing using 4-aminobenzoic acid dissolved in the oil phase. The size of the generated microparticles could be precisely controlled in the range 80 μm to 160 μm through design of the microfluidic device geometry and by varying flow rates of the dispersed and continuous phase. In contrast to free 'naked' phages, those encapsulated within the microparticles could withstand a 3 h exposure to simulated gastric fluid at pH 2 and then underwent a subsequent pH triggered burst release at pH 7. The significance of our research is in demonstrating that C. difficile specific phage can be formulated and encapsulated in highly uniform pH responsive microparticles using a microfluidic system. The microparticles were shown to afford significant protection to the encapsulated phage upon prolonged exposure to an acid solution mimicking the human stomach environment. Phage encapsulation and subsequent release kinetics revealed that the microparticles prepared using Eudragit® S100 formulations possess pH responsive characteristics with phage release triggered in an intestinal pH range suitable for therapeutic

  8. Skin metabolism of aminophenols: Human keratinocytes as a suitable in vitro model to qualitatively predict the dermal transformation of 4-amino-2-hydroxytoluene in vivo

    International Nuclear Information System (INIS)

    Goebel, C.; Hewitt, N.J.; Kunze, G.; Wenker, M.; Hein, D.W.; Beck, H.; Skare, J.

    2009-01-01

    4-Amino-2-hydroxytolune (AHT) is an aromatic amine ingredient in oxidative hair colouring products. As skin contact occurs during hair dyeing, characterisation of dermal metabolism is important for the safety assessment of this chemical class. We have compared the metabolism of AHT in the human keratinocyte cell line HaCaT with that observed ex-vivo in human skin and in vivo (topical application versus oral (p.o.) and intravenous (i.v.) route). Three major metabolites of AHT were excreted, i.e. N-acetyl-AHT, AHT-sulfate and AHT-glucuronide. When 12.5 mg/kg AHT was applied topically, the relative amounts of each metabolite were altered such that N-acetyl-AHT product was the major metabolite (66% of the dose in comparison with 37% and 32% of the same applied dose after i.v. and p.o. administration, respectively). N-acetylated products were the only metabolites detected in HaCaT cells and ex-vivo whole human skin discs for AHT and p-aminophenol (PAP), an aromatic amine known to undergo N-acetylation in vivo. Since N-acetyltransferase 1 (NAT1) is the responsible enzyme, kinetics of AHT was further compared to the standard NAT1 substrate p-aminobenzoic acid (PABA) in the HaCaT model revealing similar values for K m and V max . In conclusion NAT1 dependent dermal N-acetylation of AHT represents a 'first-pass' metabolism effect in the skin prior to entering the systemic circulation. Since the HaCaT cell model represents a suitable in vitro assay for addressing the qualitative contribution of the skin to the metabolism of topically-applied aromatic amines it may contribute to a reduction in animal testing

  9. Dendritic azo compounds as a new type amorphous molecular material with quick photoinduced surface-relief-grating formation ability

    Science.gov (United States)

    He, Yaning; Gu, Xinyu; Guo, Miaocai; Wang, Xiaogong

    2008-09-01

    A series of dendritic azobenzene-containing compounds have been synthesized as a new type amorphous molecular material, which can show quick surface-relief-grating (SRG) formation ability upon light irradiation. For the synthesis, the dendritic precursor tris(2-(ethyl(phenyl)amino)ethyl)benzene-1,3,5-tricarboxylate and tris(3,5-bis(2-(ethyl(phenyl)amino)ethoxy)benzyl)benzene-1,3,5-tricarboxylate were prepared by esterification reactions between 1,3,5-benzenetricarbonyl chloride and N-ethyl- N-hydroxyethyl-aniline and 3,5-bis[2-( N-ethylanilino)ethoxy] benzylalcohol. The precursors were, respectively reacted with the diazonium salts of 4-nitroaniline, 4-aminobenzoic acid, and 4-aminobenzonitrile to introduce different types of donor-acceptor azo chromophores at the peripheral positions. The structure and properties of the dendritic azo compounds were characterized by the spectroscopic methods and thermal analysis. The surface-relief-grating (SRG) formation behavior of the dendritic azo compounds was studied by exposing the spin-coated thin films to an interference pattern of laser beams (532 nm) at modest intensity (100 mW/cm 2). The results show that the azo compounds can form stable amorphous glasses in a broad temperature range. The glass transition temperatures ( Tgs) depend on the backbone structures and the type of the peripheral azo chromophors. The type of the electron withdrawing groups in the p-positions of the terminal azobenzene units shows a significant influence on the SRG inscription rate. For the compounds containing the same type azo chromophores, the SRG inscription rate is also affected by the backbone structure.

  10. Cellobiose Dehydrogenase Aryl Diazonium Modified Single Walled Carbon Nanotubes: Enhanced Direct Electron Transfer through a Positively Charged Surface

    Science.gov (United States)

    2011-01-01

    One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 μA cm−2 at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. PMID:21417322

  11. Covalent modification of reduced graphene oxide by means of diazonium chemistry and use as a drug-delivery system.

    Science.gov (United States)

    Wei, Guangcheng; Yan, Miaomiao; Dong, Renhao; Wang, Dong; Zhou, Xiangzhu; Chen, Jingfei; Hao, Jingcheng

    2012-11-12

    Under acidic conditions, reduced graphene oxide (rGO) was functionalized with p-aminobenzoic acid, which formed the diazonium ions through the diazotization with a wet-chemical method. Surfactants or stabilizers were not applied during the diazotization. After the functionalized rGO was treated through mild sonication in aqueous solution, these functionalized rGO sheets were less than two layers, which was determined by atomic force microscopy (AFM) imaging. The water solubility of functionalized rGO after the introduction of polyethyleneimine (PEI) was improved significantly; it was followed by covalent binding of folic acid (FA) molecules to the functionalized rGO to allow us to specifically target CBRH7919 cancer cells by using FA as a receptor. The loading and release behaviors of elsinochrome A (EA) and doxorubicin (DOX) on the functionalized rGO sheets were investigated. The EA loading ratio onto rGO-C(6)H(4)-CO-NH-PEI-NH-CO-FA (abbreviated rGO-PEI-FA, the weight ratio of drug loaded onto rGO-PEI-FA) was approximately 45.56 %, and that of DOX was approximately 28.62 %. It was interesting that the drug release from rGO-PEI-FA was pH- and salt-dependent. The results of cytotoxicity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry (FCM) assays, as well as cell morphology observations) clearly showed that the concentration of rGO-PEI-FA as the drug-delivery composite should be less than 12.5 mg L(-1). The conjugation of DOX and rGO-PEI-FA can enhance the cancer-cell apoptosis effectively and can also push the cancer cells to the vulnerable G2 phase of the cell cycle, which is most sensitive and susceptible to damage by drugs or radiation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Vitamins for enhancing plant resistance.

    Science.gov (United States)

    Boubakri, Hatem; Gargouri, Mahmoud; Mliki, Ahmed; Brini, Faiçal; Chong, Julie; Jbara, Moez

    2016-09-01

    This paper provides an overview on vitamins with inducing activities in plants, the molecular and cellular mechanisms implicated, and the hormonal signalling-network regulating this process. Moreover, it reports how vitamins might be part of the molecular events linked to induced resistance by the conventional elicitors. Induced resistance (IR), exploiting the plant innate-defense system is a sustainable strategy for plant disease control. In the last decade, vitamins have been proven to act as inducers of disease resistance, and these findings have received an important attention owing to their safety and cost effectiveness. Vitamins, including thiamine (TH, vitamin B1), riboflavin (RF, vitamin B2), menadione sodium bisulfite (MSB, vitamin K3), Para-aminobenzoic acid (PABA, vitamin Bx), and folic acid (FA, vitamin B9) provided an efficient protection against a wide range of pathogens through the modulation of specific host-defense facets. However, other vitamins, such as ascorbic acid (AA, vitamin C) and tocopherols (vitamin E), have been shown to be a part of the molecular mechanisms associated to IR. The present review is the first to summarize what vitamins are acting as inducers of disease resistance in plants and how could they be modulated by the conventional elicitors. Thus, this report provides an overview on the protective abilities of vitamins and the molecular and cellular mechanisms underlying their activities. Moreover, it describes the hormonal-signalling network regulating vitamin-signal transduction during IR. Finally, a biochemical model describing how vitamins are involved in the establishment of IR process is discussed.

  13. Evidence for an imidazoline by-product from glycans using tandem mass spectrometry.

    Science.gov (United States)

    Duff, Robert J; Smith, Elaine; Li, Wenzhou; Fodor, Szilan

    2017-06-09

    Herein is reported the separation and identification of a previously unknown imidazoline by-product originating from the fluorescent labeling procedure when applied to enzymatically released N-linked glycans of a human IgG1. The imidazoline by-product was generated via the reductive amination procedure with either sodium cyanoborohydride or 2-picoline borane. Using ultra performance liquid chromatography (UPLC) in conjunction with hydrophilic interaction-based chromatography (HILIC), the 2-aminobenzoic acid (2-AA)-labeled glycans were well-resolved from imidazoline by-products to facilitate direct identification utilizing electrospray ionization mass spectrometry (ESI-MS) with fragmentation. It was found that this minor species (∼2%) was 18.0105u less than the neighboring peak GlcNAc 2 Man 3 GlcNAc 2 Fuc peak, abbreviated as A2G0F at 1582.5899u. While this mass loss corresponds to the mass of a water molecule, the molecular location of loss of water was not straightforward in consideration of the biantennary A2G0F structure. Model studies were carried out using A2G0F standard and N-acetyllactosamine to identify the impurity as an imidazoline ring structure located at the reducing end of the glycan as confirmed by high resolution mass fragment ions. Imidazoline content decreased when the reductant concentration was increased. To conclude, evidence for the imidazoline structure was accomplished through high resolution, high accuracy mass spectrometry (HRAM), and experiments showing chemical susceptibility and isotopically labeled tracers. This study is the first to identify these minor species which likely impact all N-acetylglucosamine-type N-linked glycans from biologics. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Identification and dynamic modeling of biomarkers for bacterial uptake and effect of sulfonamide antimicrobials

    International Nuclear Information System (INIS)

    Richter, Merle K.; Focks, Andreas; Siegfried, Barbara; Rentsch, Daniel; Krauss, Martin; Schwarzenbach, René P.; Hollender, Juliane

    2013-01-01

    The effects of sulfathiazole (STA) on Escherichia coli with glucose as a growth substrate was investigated to elucidate the effect-based reaction of sulfonamides in bacteria and to identify biomarkers for bacterial uptake and effect. The predominant metabolite was identified as pterine-sulfathiazole by LC-high resolution mass spectrometry. The formation of pterine-sulfathiazole per cell was constant and independent of the extracellular STA concentrations, as they exceeded the modeled half-saturation concentration K M S of 0.011 μmol L −1 . The concentration of the dihydrofolic acid precursor para-aminobenzoic acid (pABA) increased with growth and with concentrations of the competitor STA. This increase was counteracted for higher STA concentrations by growth inhibition as verified by model simulation of pABA dynamics. The EC value for the inhibition of pABA increase was 6.9 ± 0.7 μmol L −1 STA, which is similar to that calculated from optical density dynamics indicating that pABA is a direct biomarker for the SA effect. - Highlights: ► Elucidation of the effect-based reaction of sulfonamides in bacteria. ► Identification of a biomarker for uptake and effect-based reaction of sulfonamides. ► Investigation of a biomarker for the bacterial growth inhibition by sulfonamides. ► Quantitative mechanistic modeling of biomarker dynamics using enzyme kinetics. ► Mechanistic quantitative linking of sulfonamide concentrations and effects. - Identification of specific biomarkers for the uptake and effect-based reaction of sulfonamides in bacteria and resulting growth inhibition.

  15. Characterization, liquid crystalline behavior, electrochemical and optoelectrical properties of new poly(azomethine)s and a poly(imide) with siloxane linkages

    Science.gov (United States)

    Iwan, Agnieszka; Schab-Balcerzak, Ewa; Pociecha, Damian; Krompiec, Michal; Grucela, Marzena; Bilski, Pawel; Kłosowski, Mariusz; Janeczek, Henryk

    2011-11-01

    New siloxane-containing poly(azomethine)s and a six-membered poly(imide) have been developed from siloxane-containing diamine with four different dialdehydes and 3,4,9,10-perylenetetracarboxylic dianhydride, and their thermotropic behavior, optoelectrical and electrochemical properties were examined. Mesomorphic behavior of the polymers was investigated via differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXRD, SAXRD) studies. The electrochemical behavior of poly(azomethine)s and poly(imide) was studied by differential pulse voltammetry (DPV). The HOMO levels of these polymers were in the range of -5.13 to -5.90 eV. UV-vis properties of the polymers were investigated in solid state as thin films and in chloroform solution. Optical energy band gap ( Egopt.) was calculated from absorption spectra and absorption coefficients α. The photoluminescence properties (PL) of obtained polymers were studied in chloroform solution. The investigated poly(azomethine)s emitted blue light, while the poly(imide) emitted green light. The polymers were irradiated with a test dose of 1 Gy Co-60 gamma-rays to detect their thermoluminescence properties in the temperature range of 50-200 °C. Polymer monolayer (ITO/polymer/Al) and bulk heterojunction (BHJ) (ITO/polymer:PCBM/Al and ITO/PEDOT:PSS/polymer:PCBM/Al) devices were prepared with PAZ and PI used as active layers and I- U curves were measured in the dark and during irradiation with light (under illumination of 1000 W/m 2). Poly(azomethine)s were blended with [6,6]-phenyl C 61 butyric acid methyl ester (PCBM). Selected properties of the investigated polymers with siloxane linkages were compared with the polymers ( PAZ1a- PAZ3a, PIa) prepared from the same dialdehydes or dianhydride and poly(1,4-butanediol)bis(4-aminobenzoate).

  16. Electroactive crown ester-Cu2+ complex with in-situ modification at molecular beacon probe serving as a facile electrochemical DNA biosensor for the detection of CaMV 35s.

    Science.gov (United States)

    Zhan, Fengping; Liao, Xiaolei; Gao, Feng; Qiu, Weiwei; Wang, Qingxiang

    2017-06-15

    A novel electrochemical DNA biosensor has been facilely constructed by in-situ assembly of electroactive 4'-aminobenzo-18-crown-6-copper(II) complex (AbC-Cu 2+ ) on the free terminal of the hairpin-structured molecule beacon. The 3'-SH modified molecule beacon probe was first immobilized on the gold electrode (AuE) surface through self-assembly chemistry of Au-S bond. Then the crow ester of AbC was covalently coupled with 5'-COOH on the molecule beacon, and served as a platform to attach the Cu 2+ by coordination with ether bond (-O-) of the crown cycle. Thus, an electroactive molecule beacon-based biosensing interface was constructed. In comparison with conventional methods for preparation of electroactive molecule beacon, the approach presented in this work is much simpler, reagent- and labor-saving. Selectivity study shows that the in-situ fabricated electroactive molecule beacon remains excellent recognition ability of pristine molecule beacon probe to well differentiate various DNA fragments. The target DNA can be quantatively determined over the range from 0.10pM to 0.50nM. The detection limit of 0.060pM was estimated based on signal-to-noise ratio of 3. When the biosensor was applied for the detection cauliflower mosaic virus 35s (CaMV 35s) in soybean extraction samples, satisfactory results are achieved. This work opens a new strategy for facilely fabricating electrochemical sensing interface, which also shows great potential in aptasensor and immurosensor fabrication. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Functional polyaniline nanofibre mats for human adipose-derived stem cell proliferation and adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Abdul Rahman, Norizah, E-mail: norizah@science.putra.edu.my [Polymer Electronics Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Department of Chemistry, University of Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan (Malaysia); Feisst, Vaughan [School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Dickinson, Michelle E. [Department of Chemical and Materials Engineering, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Malmström, Jenny [Polymer Electronics Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Dunbar, P. Rod [School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Maurice Wilkins Centre, Private Bag 92019, Auckland (New Zealand); Travas-Sejdic, Jadranka, E-mail: j.travas-sejdic@auckland.ac.nz [Polymer Electronics Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); MacDiarmid Institute for Advanced Materials and Nanotechnology, P.O. Box 600, Wellington 6140 (New Zealand)

    2013-02-15

    Conductive polymer poly(aniline-co-m-aminobenzoic acid) (P(ANI-co-m-ABA)) and polyaniline (PANI) were blended with a biodegradable, biocompatible polymer, poly(L-lactic acid) and were electrospun into nanofibres to investigate their potential application as a scaffold for human adipose-derived stem cells (hASCs). These polymers, in both conductive and non-conductive form, were electrospun with average fibre diameters of less than 400 nm. Novel nanoindentation results obtained on the individual nanofibres revealed that the elastic moduli of the nanofibres are much higher at the surface (4–10 GPa, h{sub max} <75 nm) than in the inner fibre core (2–4 GPa, h{sub max} >75 nm). The composite nanofibres showed great promise as a scaffold for hASCs as they supported the cell adhesion and proliferation. After 1 week of cell culture hASCs were well spread on the substrates with abundant focal adhesions. The electrospun mats provide the cells with comparably stiff, sub-micron sized fibres as anchoring points on a substrate of high porosity. The conductive nature of these composite nanofibres offers exciting opportunities for electrical stimulation of the cells. - Highlights: ► Polyaniline and its copolymer's nanofibres were prepared by electrospinning. ► The elastic modulus of a single polyaniline composite nanofibres were determined. ► Elastic moduli of the nanofibres are much higher at the surface than the inner core. ► The electrospun mats supported the cell adhesion and proliferation. ► The nanofibres show great promise as a scaffold for adipose derived stem cells.

  18. Rationalization of reduced penetration of drugs through ceramide gel phase membrane.

    Science.gov (United States)

    Paloncýová, Markéta; DeVane, Russell H; Murch, Bruce P; Berka, Karel; Otyepka, Michal

    2014-11-25

    Since computing resources have advanced enough to allow routine molecular simulation studies of drug molecules interacting with biologically relevant membranes, a considerable amount of work has been carried out with fluid phospholipid systems. However, there is very little work in the literature on drug interactions with gel phase lipids. This poses a significant limitation for understanding permeation through the stratum corneum where the primary pathway is expected to be through a highly ordered lipid matrix. To address this point, we analyzed the interactions of p-aminobenzoic acid (PABA) and its ethyl (benzocaine) and butyl (butamben) esters with two membrane bilayers, which differ in their fluidity at ambient conditions. We considered a dioleoylphosphatidylcholine (DOPC) bilayer in a fluid state and a ceramide 2 (CER2, ceramide NS) bilayer in a gel phase. We carried out unbiased (100 ns long) and biased z-constraint molecular dynamics simulations and calculated the free energy profiles of all molecules along the bilayer normal. The free energy profiles converged significantly slower for the gel phase. While the compounds have comparable affinities for both membranes, they exhibit penetration barriers almost 3 times higher in the gel phase CER2 bilayer. This elevated barrier and slower diffusion in the CER2 bilayer, which are caused by the high ordering of CER2 lipid chains, explain the low permeability of the gel phase membranes. We also compared the free energy profiles from MD simulations with those obtained from COSMOmic. This method provided the same trends in behavior for the guest molecules in both bilayers; however, the penetration barriers calculated by COSMOmic did not differ between membranes. In conclusion, we show how membrane fluid properties affect the interaction of drug-like molecules with membranes.

  19. Structural features of lipoarabinomannan from Mycobacterium bovis BCG. Determination of molecular mass by laser desorption mass spectrometry.

    Science.gov (United States)

    Venisse, A; Berjeaud, J M; Chaurand, P; Gilleron, M; Puzo, G

    1993-06-15

    It was recently shown that mycobacterial lipoarabinomannan (LAM) can be classified into two types (Chatterjee, D., Lowell, K., Rivoire B., McNeil M. R., and Brennan, P. J. (1992) J. Biol. Chem. 267, 6234-6239) according to the presence or absence of mannosyl residues (Manp) located at the nonreducing end of the oligoarabinosyl side chains. These two types of LAM were found in a pathogenic Mycobacterium tuberculosis strain and in an avirulent M. tuberculosis strain, respectively, suggesting that LAM with Manp characterizes virulent and "disease-inducing strains." We now report the structure of the LAM from Mycobacterium bovis Bacille Calmette-Guérin (BCG) strain Pasteur, largely used throughout the world as vaccine against tuberculosis. Using an up-to-date analytical approach, we found that the LAM of M. bovis BCG belongs to the class of LAMs capped with Manp. By means of two-dimensional homonuclear and heteronuclear scalar coupling NMR analysis and methylation data, the sugar spin system assignments were partially established, revealing that the LAM contained two types of terminal Manp and 2-O-linked Manp. From the following four-step process: (i) partial hydrolysis of deacylated LAM (dLAM), (ii) oligosaccharide derivatization with aminobenzoic ethyl ester, (iii) HPLC purification, (iv) FAB/MS-MS analysis; it was shown that the dimannosyl unit alpha-D-Manp-(1-->2)-alpha-D-Manp is the major residue capping the termini of the arabinan of the LAM. In this report, LAM molecular mass determination was established using matrix-assisted UV-laser desorption/ionization mass spectrometry which reveals that the LAM molecular mass is around 17.4 kDa. The similarity of the LAM structures between M. bovis BCG and M. tuberculosis H37Rv is discussed in regard to their function in the immunopathology of mycobacterial infection.

  20. Uranyl(VI) and lanthanum(III) complexes with functionalized macrocyclic and macroacyclic Schiff bases

    International Nuclear Information System (INIS)

    Aguiari, A.; Brianese, N.; Tamburini, S.; Vigato, P.A.

    1995-01-01

    Acyclic Schiff bases have been prepared by [2 + 1] condensation of 2,6-diformyl-4-chlorophenol and H 2 NCH 2 [CH 2 XCH 2 ] n CH 2 NH 2 (n =3D 0 H 2 -I; X =3D NH, S, O n =3D 1 H 2 -II...H 2 -IV; X =3D 0 n =3D 2 H 2 -V; X =3D 0 n =3D 3 H 2 -VI). The related uranlyl(VI) and lanthanum (III) complexes have bee synthesized by reaction by reaction of the preformed ligands with the appropriate salt or by the template procedure, in the presence of base. No base was employed in the preparation of lanthanum (III) complexes, La(H 2 -II)(NO 3 ) 3 , La(H 2 -IV)(NO 3 ) 3 where the Schiff bases coordinate as neutral chelate ligands. These acyclic complexes have been used for further condensation, and symmetric and asymmetric cyclic complexes have been obtained by their reaction with the polyamines H 2 NCH 2 [CH 2 XCH 2 ]nCH 2 NH 2 or with 4,4'-diaminodibenzo -18-crown-6. By reaction with 4-aminobenzo-15-crown-5 or 2-amino-methyl-15-crown-5, the same acyclic complexes give rise to functionalized complexes bearing crown-ether moieties. Analogously, the acyclic ligand H 3 -IXX, prepared by condensation of 2,6 diformyl-4-chlorophenol and tris(aminoethyl)amine, forms mono and homodinuclear lanthanum (III) complexes, which may undergo further condensation when reacted with primary functionalized amines. (authors). 42 refs., 2 figs., 2 schemes, 1 tab

  1. Prussian blue mediated amplification combined with signal enhancement of ordered mesoporous carbon for ultrasensitive and specific quantification of metolcarb by a three-dimensional molecularly imprinted electrochemical sensor.

    Science.gov (United States)

    Yang, Yukun; Cao, Yaoyu; Wang, Xiaomin; Fang, Guozhen; Wang, Shuo

    2015-02-15

    In this work, we presented a three-dimensional (3D) molecularly imprinted electrochemical sensor (MIECS) with novel strategy for ultrasensitive and specific quantification of metolcarb based on prussian blue (PB) mediated amplification combined with signal enhancement of ordered mesoporous carbon. The molecularly imprinted polymers were synthesized by electrochemically induced redox polymerization of para aminobenzoic acid (p-ABA) in the presence of template metolcarb. Ordered mesoporous carbon material (CMK-3) was introduced to enhance the electrochemical response by improving the structure of the modified electrodes and facilitating charge transfer processes of PB which was used as an inherent electrochemical active probe. The modification process for the working electrodes of the MIECS was characterized by scanning electron microscope (SEM) and cyclic voltammetry (CV), and several important parameters controlling the performance of the MIECS were investigated and optimized in detail. The MIECS with 3D structure had the advantages of ease of preparation, high porous surface structure, speedy response, ultrasensitivity, selectivity, reliable stability, good reproducibility and repeatability. Under the optimal conditions, the MIECS offered an excellent current response for metolcarb in the linear response range of 5.0 × 10(-10)-1.0 × 10(-4) mol L(-1) and the limit of detection (LOD) was calculated to be 9.3 × 10 (-11)mol L(-1) (S/N = 3). The proposed MIECS has been successfully applied for the determination of metolcarb in real samples with satisfactory recoveries. Furthermore, the construction route of this ultrasensitive 3D MIECS may provide a guideline for the determination of non-electroactive analytes in environmental control and food safety. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Identifying target processes for microbial electrosynthesis by elementary mode analysis.

    Science.gov (United States)

    Kracke, Frauke; Krömer, Jens O

    2014-12-30

    Microbial electrosynthesis and electro fermentation are techniques that aim to optimize microbial production of chemicals and fuels by regulating the cellular redox balance via interaction with electrodes. While the concept is known for decades major knowledge gaps remain, which make it hard to evaluate its biotechnological potential. Here we present an in silico approach to identify beneficial production processes for electro fermentation by elementary mode analysis. Since the fundamentals of electron transport between electrodes and microbes have not been fully uncovered yet, we propose different options and discuss their impact on biomass and product yields. For the first time 20 different valuable products were screened for their potential to show increased yields during anaerobic electrically enhanced fermentation. Surprisingly we found that an increase in product formation by electrical enhancement is not necessarily dependent on the degree of reduction of the product but rather the metabolic pathway it is derived from. We present a variety of beneficial processes with product yield increases of maximal 36% in reductive and 84% in oxidative fermentations and final theoretical product yields up to 100%. This includes compounds that are already produced at industrial scale such as succinic acid, lysine and diaminopentane as well as potential novel bio-commodities such as isoprene, para-hydroxybenzoic acid and para-aminobenzoic acid. Furthermore, it is shown that the way of electron transport has major impact on achievable biomass and product yields. The coupling of electron transport to energy conservation could be identified as crucial for most processes. This study introduces a powerful tool to determine beneficial substrate and product combinations for electro-fermentation. It also highlights that the maximal yield achievable by bio electrochemical techniques depends strongly on the actual electron transport mechanisms. Therefore it is of great importance to

  3. A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

    2017-07-01

    Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

  4. Porous Nano-Si/Carbon Derived from Zeolitic Imidazolate Frameworks@Nano-Si as Anode Materials for Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Song, Yonghai; Zuo, Li; Chen, Shouhui; Wu, Jiafeng; Hou, Haoqing; Wang, Li

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •The porous cage-like carbon/Si nanocomposites were synthesized based on nano-Si@ZIF-8-templatedmethod. •The nano-Si was uniformly embedded in porous amorphous carbon matrices. •The porous dodecahedral carbon framework effectively accommodates the volume variation of Si during the discharge/charge process. •The Si/C nanocomposites exhibit superior reversible capacity of 1168 mA h g −1 after 100 cycles. -- Abstract: Novel porous cage-like carbon (C)/nano-Si nanocomposites as anode materials for lithium-ion batteries (LIBs) was prepared based on nano-Si@zeolitic imidazolate frameworks (ZIF-8)-templated method. In this strategy, p-aminobenzoic acid was initially grafted onto nano-Si to form benzoic acid-functionalized nano-Si, and then nano-Si@ZIF-8 was constructed by alternately growing Zn(NO 3 ) 2 ·6H 2 O and 2-methylimidazolate on benzoic acid-functionalized nano-Si under ultrasound. The novel porous cage-like nano-Si/C nanocomposites were fabricated by pyrolyzing the resulted nano-Si@ZIF-8 and washing with HCl to remove off ZnO. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectra and N 2 adsorption/desorption isotherms were employed to characterize the porous cage-like nano-Si/C nanocomposites. The resulted nano-Si/C nanocomposites as anode materials for LIBs showed a high reversible capacity of ∼1168 mA h g −1 at 100 mA g −1 after 100 cycles, which was higher than many previously reported Si/C nanocomposites. The porous nanostructure, high specific surface area and good electrical conductivity of the cage-like nano-Si/C nanocomposites contributed together to the good performance for LIBs. It might open up a new way for application of silicon materials

  5. Non-porous membrane-assisted liquid-liquid extraction of UV filter compounds from water samples.

    Science.gov (United States)

    Rodil, Rosario; Schrader, Steffi; Moeder, Monika

    2009-06-12

    A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes non-porous membrane-assisted liquid-liquid extraction (MALLE) and LC-atmospheric pressure photoionization (APPI)-MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made membrane bags were prepared from low-density polyethylene in order to accommodate 100 microL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L(-1) (OD-PABA) and 16 ng L(-1) (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L(-1) (BP-3) and 4381 ng L(-1) (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L(-1) (OC).

  6. Ultraviolet filters differentially impact the expression of key endocrine and stress genes in embryos and larvae of Chironomus riparius.

    Science.gov (United States)

    Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2016-07-01

    Several organic UV filters have hormonal activity in vertebrates, as demonstrated in fishes, rodents and human cells. Despite the accumulation of filter contaminants in aquatic systems, research on their effects on the endocrine systems of freshwaters invertebrates is scarce. In this work, the effects of five frequently used UV filters were investigated in embryos and larvae of Chironomus riparius, which is a reference organism in ecotoxicology. LC50 values for larvae as well as the percentage of eclosion of eggs were determined following exposures to: octyl-p-methoxycinnamate (OMC) also known as 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4MBC); 4-hydroxybenzophenone (4HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). To assess sublethal effects, expression levels of the genes coding for the ecdysone receptor (EcR) and heat shock protein HSP70 were investigated as biomarkers for endocrine and stress effects at the cellular level. Life-stage-dependent sensitivity was found. In embryos, all of the UV filters provoked a significant overexpression of EcR at 24h after exposure. OC, 4MBC and OD-PABA also triggered transcriptional activation of the hsp70 stress gene in embryos. In contrast, in larvae, only 4MBC and OMC/EHMC increased EcR and hsp70 mRNA levels and OD-PABA upregulated only the EcR gene. These results revealed that embryos are particularly sensitive to UV filters, which affect endocrine regulation during development. Most UV filters also triggered the cellular stress response, and thus exhibit proteotoxic effects. The differences observed between embryos and larvae and the higher sensitivity of embryos highlight the importance of considering different life stages when evaluating the environmental risks of pollutants, particularly when analyzing endocrine effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Reactive low temperature plasma ionization mass spectrometry for the determination of organic UV filters in personal care products.

    Science.gov (United States)

    Ding, Xuelu; Gerbig, Stefanie; Spengler, Bernhard; Schulz, Sabine

    2018-02-01

    Organic UV filters in personal care products (PCPs) have been persistently reported as a potential threat to human health. In order to guarantee consumers ' safety, the dose of these compounds in PCPs needs to be monitored. Here, a methodology based on reactive low temperature plasma ionization (LTP) mass spectrometry (MS) has been developed for the determination of common organic UV filters in PCPs including benzophenone-3, ethylhexyl dimethyl p-aminobenzoic acid, ethylhexyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, and ethylhexyl salicylate. The experiments were carried out in transmission geometry where the LTP ion source, samples loaded on a stainless steel mesh, and the MS inlet were aligned coaxially. Four chemicals, ammonia, ammonium formate, aniline, and methylamine were considered as reactive additives allowing reactions with the UV filters through different mechanisms. Methylamine-induced reactive LTP-MS showed the most prominent improvement on the detection of UV filter compounds. Compared to direct LTP-MS, the developed method improved the detection limits of UV filters more than 10 fold. Moreover, the method enabled fast semi-quantitative screening of UV filters in authentic PCPs. Concentrations of active ingredients in eight authentic PCPs as determined with reactive LTP-MS were found comparable to values offered by the cosmetic companies and corresponding HPLC data. The methodology provides high throughput analysis (70s per sample) and sensitive identification of organic UV filters. Lowest detectable concentrations ranged from 0.13µg/g for 4-methylbenzylidene camphor to 7.67µg/g for octocrylene in spiked cream. In addition, it shows the potential to be used as a screening tool for legal authentications of these chemicals in the future due to its semi-quantitative determination of UV filters in PCPs without tedious sample preparation and time-consuming chromatographic separation. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. [Discover potential inhibitors of 5-LOX and LTA4H from Rhei Radix et Rhizoma, Notopterygii Rhizoma et Radix and Genitana Macrophyllae Radix based on molecular simulation methods].

    Science.gov (United States)

    Gu, Yu; Zhang, Xu; Chen, Yan-Kun; Zhao, Bo-Wen; Zhang, Yan-Ling

    2017-12-01

    5-lipoxygenase (5-LOX) and leukotriene A4 hydrolase (LTA4H), as the major targets of 5-LOX branch in the arachidonic acid (AA) metabolic pathway, play an important role in the treatment of inflammation. Rhei Radix et Rhizoma, Notopterygii Rhizoma et Radix and Genitana Macrophyllae Radix have clear anti-inflammation activities. In this paper, the targets of 5-LOX and LTA4H were used as the research carrier, and Hiphop module in DS4.0 (Discovery studio) was used to construct ingredients database for preliminary screening of three traditional Chinese medicines based on target inhibitor pharmacophore, so as to obtain 5-LOX and LTA4H potential active ingredients. The ingredients obtained in initial pharmacophore screening were further screened by using CDOCKER module, and the screening rules were established based on the score of initial compound and the key amino acids to obtain 12 potential 5-LOX inhibitors and 7 potential LTA4H inhibitors. To be more specific, the potential 5-LOX inhibitors included 6 ingredients in Rhei Radix et Rhizoma, such as procyanidins B2-3,3'-O-double gallate and revandchinone 2; four ingredients in notopterygium, such as dodecanoic acid and so on. On the other hand, potential LTA4H inhibitors included revandchinone 1, revandchinone 4 in Rhei Radix et Rhizoma, tridecanoic acid, tetracosanoic acid and methyl eicosanoate in Notopterygii Rhizoma et Radix, montanic acid methyl ester and N-docosanoyl-O-aminobenzoate in Genitana Macrophyllae Radix and so on. The molecular simulation methods were highly efficient and time-saving to obtain the potential inhibitors of 5-LOX and LTA4H, which could provide assistance for discovering the chemical quality indicators of anti-inflammatory efficacy of three Chinese herbs, and may be helpful to promote the whole-process quality control of three Chinese herbs. Copyright© by the Chinese Pharmaceutical Association.

  9. Unique anthranilic acid chemistry facilitates profiling and characterization of Ser/Thr-linked sugar chains following hydrazinolysis.

    Science.gov (United States)

    Anumula, Kalyan Rao

    2008-02-01

    A novel method for the analysis of Ser/Thr-linked sugar chains was made possible by the virtue of unique anthranilic acid (AA, 2-aminobenzoic acid [2AA]) chemistry for labeling carbohydrates in aqueous salt solutions (K. R. Anumula, Anal. Biochem. 350 (2006) 1-23). The protocol for profiling of Ser/Thr carbohydrates by hydrazinolysis was made simple by eliminating intermediary isolation steps involved in a sample preparation such as desalting and various chromatographic purification schemes. A 6-h hydrazinolysis was carried out at 60 degrees C for O-linked oligosaccharides and at 95 degrees C for total oligosaccharides (N-linked with some O-linked). Following evaporation of hydrazine (<10 min), the oligosaccharides were N-acetylated and derivatized with AA in the same reaction mixture containing salts. Presumably, the glycosyl-hydrazines/hydrazones present in the mixture did not interfere with AA labeling. Because AA is the most fluorescent and highly reactive tag for labeling carbohydrates, the procedures described are suitable for the analysis of a limited amount of samples ( approximately 5 microg) by the current high-resolution high-performance liquid chromatography (HPLC) methods. HPLC conditions developed for the separation of O-linked sugar chains based on size on an amide column were satisfactory for quantitative profiling and characterization. Common O-linked sugar chains found in fetuin, equine chorionic gonadotropin, and glycophorin can be analyzed in less than 50 min. In addition, these fast profiling methods were comparable to profiling by PNGase F (peptide N-glycosidase from Flavobacterium meningosepticum) digestion in terms of time, effort, and simplicity and also were highly reproducible for routine testing. The procedures for the release of sugar chains by hydrazinolysis at the microgram level, labeling with fluorescent tag AA, and profiling by HPLC should be useful in characterization of carbohydrates found in glycoproteins.

  10. A pyrroloquinolinequinone-dependent glucose dehydrogenase (PQQ-GDH)-electrode with direct electron transfer based on polyaniline modified carbon nanotubes for biofuel cell application

    International Nuclear Information System (INIS)

    Schubart, Ivo W.; Göbel, Gero; Lisdat, Fred

    2012-01-01

    Graphical abstract: - Abstract: In this study we present a pyrroloquinolinequinone-dependent glucose dehydrogenase [(PQQ)-GDH] electrode with direct electron transfer between the enzyme and electrode. Soluble pyrroloquinolinequinone-dependent glucose dehydrogenase from Acinetobacter calcoaceticus is covalently bound to an electropolymerized polyaniline copolymer film on a multi-walled carbon nanotube (MWCNT)-modified gold electrode. The pulsed electropolymerization of 2-methoxyaniline-5-sulfonic acid (MASA) and m-aminobenzoic acid (ABA) is optimized with respect to the efficiency of the bioelectrocatalytic conversion of glucose. The glucose oxidation starts at −0.1 V vs. Ag/AgCl and current densities up to 500 μA/cm 2 at low potential of +0.1 V vs. Ag/AgCl can be achieved. The electrode shows a glucose sensitivity in the range from 0.1 mM to 5 mM at a potential of +0.1 V vs. Ag/Ag/Cl. The dynamic range is extended to 100 mM at +0.4 V vs. Ag/AgCl. The electron transfer mechanism is studied and buffer effects are investigated. The developed enzyme electrode is examined for bioenergetic application by assembling of a membrane-less biofuel cell. For the cathode a bilirubin oxidase (BOD) based MWCNT-modified gold electrode with direct electron transfer (DET) is used. The biofuel cell exhibits a cell potential of 680 ± 20 mV and a maximum power density of up to 65 μW/cm 2 at 350 mV vs. Ag/AgCl.

  11. N-glycosylation of Colorectal Cancer Tissues

    Science.gov (United States)

    Balog, Crina I. A.; Stavenhagen, Kathrin; Fung, Wesley L. J.; Koeleman, Carolien A.; McDonnell, Liam A.; Verhoeven, Aswin; Mesker, Wilma E.; Tollenaar, Rob A. E. M.; Deelder, André M.; Wuhrer, Manfred

    2012-01-01

    Colorectal cancer is the third most common cancer worldwide with an annual incidence of ∼1 million cases and an annual mortality rate of ∼655,000 individuals. There is an urgent need for identifying novel targets to develop more sensitive, reliable, and specific tests for early stage detection of colon cancer. Post-translational modifications are known to play an important role in cancer progression and immune surveillance of tumors. In the present study, we compared the N-glycan profiles from 13 colorectal cancer tumor tissues and corresponding control colon tissues. The N-glycans were enzymatically released, purified, and labeled with 2-aminobenzoic acid. Aliquots were profiled by hydrophilic interaction liquid chromatography (HILIC-HPLC) with fluorescence detection and by negative mode MALDI-TOF-MS. Using partial least squares discriminant analysis to investigate the N-glycosylation changes in colorectal cancer, an excellent separation and prediction ability were observed for both HILIC-HPLC and MALDI-TOF-MS data. For structure elucidation, information from positive mode ESI-ion trap-MS/MS and negative mode MALDI-TOF/TOF-MS was combined. Among the features with a high separation power, structures containing a bisecting GlcNAc were found to be decreased in the tumor, whereas sulfated glycans, paucimannosidic glycans, and glycans containing a sialylated Lewis type epitope were shown to be increased in tumor tissues. In addition, core-fucosylated high mannose N-glycans were detected in tumor samples. In conclusion, the combination of HILIC and MALDI-TOF-MS profiling of N-glycans with multivariate statistical analysis demonstrated its potential for identifying N-glycosylation changes in colorectal cancer tissues and provided new leads that might be used as candidate biomarkers. PMID:22573871

  12. Solid-phase reductive amination for glycomic analysis.

    Science.gov (United States)

    Jiang, Kuan; Zhu, He; Xiao, Cong; Liu, Ding; Edmunds, Garrett; Wen, Liuqing; Ma, Cheng; Li, Jing; Wang, Peng George

    2017-04-15

    Reductive amination is an indispensable method for glycomic analysis, as it tremendously facilitates glycan characterization and quantification by coupling functional tags at the reducing ends of glycans. However, traditional in-solution derivatization based approach for the preparation of reductively aminated glycans is quite tedious and time-consuming. Here, a simpler and more efficient strategy termed solid-phase reductive amination was investigated. The general concept underlying this new approach is to streamline glycan extraction, derivatization, and purification on non-porous graphitized carbon sorbents. Neutral and sialylated standard glycans were utilized to test the feasibility of the solid-phase method. As results, almost complete labeling of those glycans with four common labels of aniline, 2-aminobenzamide (2-AB), 2-aminobenzoic acid (2-AA) and 2-amino-N-(2-aminoethyl)-benzamide (AEAB) was obtained, and negligible desialylation occurred during sample preparation. The labeled glycans derived from glycoproteins showed excellent reproducibility in high performance liquid chromatography (HPLC) and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. Direct comparisons based on fluorescent absorbance and relative quantification using isotopic labeling demonstrated that the solid-phase strategy enabled 20-30% increase in sample recovery. In short, the solid-phase strategy is simple, reproducible, efficient, and sensitive for glycan analysis. This method was also successfully applied for N-glycan profiling of HEK 293 cells with MALDI-TOF MS, showing its attractive application in the high-throughput analysis of mammalian glycome. Published by Elsevier B.V.

  13. High-throughput determination of urinary hexosamines for diagnosis of mucopolysaccharidoses by capillary electrophoresis and high-performance liquid chromatography.

    Science.gov (United States)

    Coppa, Giovanni V; Galeotti, Fabio; Zampini, Lucia; Maccari, Francesca; Galeazzi, Tiziana; Padelia, Lucia; Santoro, Lucia; Gabrielli, Orazio; Volpi, Nicola

    2011-04-01

    Mucopolysaccharidoses (MPS) diagnosis is often delayed and irreversible organ damage can occur, making possible therapies less effective. This highlights the importance of early and accurate diagnosis. A high-throughput procedure for the simultaneous determination of glucosamine and galactosamine produced from urinary galactosaminoglycans and glucosaminoglycans by capillary electrophoresis (CE) and HPLC has been performed and validated in subjects affected by various MPS including their mild and severe forms, Hurler and Hurler-Scheie, Hunter, Sanfilippo, Morquio, and Maroteaux-Lamy. Contrary to other analytical approaches, the present single analytical procedure, which is able to measure total abnormal amounts of urinary GAGs, high molecular mass, and related fragments, as well as specific hexosamines belonging to a group of GAGs, would be useful for possible application in their early diagnosis. After a rapid urine pretreatment, free hexosamines are generated by acidic hydrolysis, derivatized with 2-aminobenzoic acid and separated by CE/UV in ∼10min and reverse-phase (RP)-HPLC in fluorescence in ∼21min. The total content of hexosamines was found to be indicative of abnormal urinary excretion of GAGs in patients compared to the controls, and the galactosamine/glucosamine ratio was observed to be related to specific MPS syndromes in regard to both their mild and severe forms. As a consequence, important correlations between analytical response and clinical diagnosis and the severity of the disorders were observed. Furthermore, we can assume that the severity of the syndrome may be ascribed to the quantity of total GAGs, as high-molecular-mass polymers and fragments, accumulated in cells and directly excreted in the urine. Finally, due to the high-throughput nature of this approach and to the equipment commonly available in laboratories, this method is suitable for newborn screening in preventive public health programs for early detection of MPS disorders

  14. Analytical characterization of ch14.18: a mouse-human chimeric disialoganglioside-specific therapeutic antibody.

    Science.gov (United States)

    Soman, Gopalan; Kallarakal, Abraham T; Michiel, Dennis; Yang, Xiaoyi; Saptharish, Nirmala; Jiang, Hengguang; Giardina, Steve; Gilly, John; Mitra, George

    2012-01-01

    Ch14.18 is a mouse-human chimeric monoclonal antibody to the disialoganglioside (GD2) glycolipid. In the clinic, this antibody has been shown to be effective in the treatment of children with high-risk neuroblastoma, either alone or in combination therapy. Extensive product characterization is a prerequisite to addressing the potential issues of product variability associated with process changes and manufacturing scale-up. Charge heterogeneity, glycosylation profile, molecular state and aggregation, interaction (affinity) with Fcγ receptors and functional or biological activities are a few of the critical characterization assays for assessing product comparability for this antibody. In this article, we describe the in-house development and qualification of imaged capillary isoelectric focusing to assess charge heterogeneity, analytical size exclusion chromatography with online static and dynamic light scattering (DLS), batch mode DLS for aggregate detection, biosensor (surface plasmon resonance)-based Fcγ receptor antibody interaction kinetics, N-glycoprofiling with PNGase F digestion, 2-aminobenzoic acid labeling and high performance liquid chromatography and N-glycan analysis using capillary electrophoresis. In addition, we studied selected biological activity assays, such as complement-dependent cytotoxicity. The consistency and reproducibility of the assays are established by comparing the intra-day and inter-day assay results. Applications of the methodologies to address stability or changes in product characteristics are also reported. The study results reveal that the ch14.18 clinical product formulated in phosphate-buffered saline at a concentration of 5 mg/ml and stored at 2-8°C is stable for more than five years.

  15. Rhenium(V) oxo complexes relevant to technetium renal imaging agents derived from mercaptoacetylglycylglycylaminobenzoic acid isomers. Structural and molecular mechanics studies

    International Nuclear Information System (INIS)

    Hansen, L.; Taylor, A. Jr; Marzilli, L.G.; Cini, R.

    1992-01-01

    The synthesis and characterization of three rhenium(V) oxo complexes derived from isomers of mercaptoacetylglycylglycylaminobenzoic acid (MAG 2 -ABAH 5 ) are reported. The isomers were synthesized from o-, m- and p-aminobenzoic acid and differed in the position of the terminal carboxyl group. The anions of 8-10, [ReO(MAG 2 -*ABAH)] - (* = para (8), meta (9), ortho (10)), contained the tetraanionic form of the ligands with the carboxyl group protonated. Compounds 8,9, and 10 were synthesized by exchange reactions of ReOCl 3 (Me 2 SO)(Ph 3 P) under moderate conditions and were isolated as [Ph 4 P] + , [Bu 4 N] + , and [Ph 4 P] + salts, respectively. The structures of 8 and 10 were determined by X-ray diffraction methods; except for the location of the carboxyl group, the structures are similar. The coordination geometry is pseudo square pyramidal, with nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The orientation of the carboxyl group in 10 is anti to the Re double-bond O group. Since the carboxyl groups are protonated in 8 and 10 and in other relevant structures from this class of radiopharmaceuticals including [Ph 4 As][TcO(MAG 3 H)] (MAG 3 H = tetraanionic form of mercaptoacetyltriglycine), the authors developed molecular mechanics parameters that allowed them to calculate the structures of 8, 10, and [TcO(MAG 3 H)] - . They then extended the calculations to all three isomeric complexes in their deprotonated forms and to [TcO(MAG 3 )] 2- in order to approximate their solution phase structures. They conclude that the [TcO(MAG 3 )] 2- species is conformationally flexible, and they have made an initial assessment of structures vs renal clearance

  16. N-glycosylation of colorectal cancer tissues: a liquid chromatography and mass spectrometry-based investigation.

    Science.gov (United States)

    Balog, Crina I A; Stavenhagen, Kathrin; Fung, Wesley L J; Koeleman, Carolien A; McDonnell, Liam A; Verhoeven, Aswin; Mesker, Wilma E; Tollenaar, Rob A E M; Deelder, André M; Wuhrer, Manfred

    2012-09-01

    Colorectal cancer is the third most common cancer worldwide with an annual incidence of ~1 million cases and an annual mortality rate of ~655,000 individuals. There is an urgent need for identifying novel targets to develop more sensitive, reliable, and specific tests for early stage detection of colon cancer. Post-translational modifications are known to play an important role in cancer progression and immune surveillance of tumors. In the present study, we compared the N-glycan profiles from 13 colorectal cancer tumor tissues and corresponding control colon tissues. The N-glycans were enzymatically released, purified, and labeled with 2-aminobenzoic acid. Aliquots were profiled by hydrophilic interaction liquid chromatography (HILIC-HPLC) with fluorescence detection and by negative mode MALDI-TOF-MS. Using partial least squares discriminant analysis to investigate the N-glycosylation changes in colorectal cancer, an excellent separation and prediction ability were observed for both HILIC-HPLC and MALDI-TOF-MS data. For structure elucidation, information from positive mode ESI-ion trap-MS/MS and negative mode MALDI-TOF/TOF-MS was combined. Among the features with a high separation power, structures containing a bisecting GlcNAc were found to be decreased in the tumor, whereas sulfated glycans, paucimannosidic glycans, and glycans containing a sialylated Lewis type epitope were shown to be increased in tumor tissues. In addition, core-fucosylated high mannose N-glycans were detected in tumor samples. In conclusion, the combination of HILIC and MALDI-TOF-MS profiling of N-glycans with multivariate statistical analysis demonstrated its potential for identifying N-glycosylation changes in colorectal cancer tissues and provided new leads that might be used as candidate biomarkers.

  17. Production and analysis of organic acids in hairy-root cultures of Isatis indigotica Fort. (indigo woad).

    Science.gov (United States)

    Xu, Tiefeng; Zhang, Lei; Sun, Xiaofen; Zhang, Hanming; Tang, Kexuan

    2004-02-01

    Hairy roots were induced from both cotyledon and hypocotyl explants of Isatis indigotica Fort. (indigo woad) through transformation with Agrobaterium rhizogenes strain A4, R1601 and ATCC15834. The results showed that the cotyledons were the preferred explants to hypocotyls and A4 was the most suitable A. rhizogenes strain for the transformation and induction of hairy roots of I. indigotica. High-voltage paper electrophoresis (HVPE) analysis demonstrated the production of mannopine in hairy roots and confirmed the successful transfer of Ri T-DNA (root-inducing transferred DNA) of A. rhizogenes into the I. indigotica genome. Five organic acids, namely CPQ [3-(2-carboxyphenol)-4(3 H )-quinazolinone], syringic acid, salicylic acid, benzoic acid and 2-aminobenzoic acid, which were considered as main antiviral components of I. indigotica, were detected in natural roots, hairy roots and liquid media with high-performance capillary electrophoresis. The results showed CPQ production in hairy roots was significantly higher than that in natural roots. Our results also revealed that all the five organic acids could be excreted from hairy roots into liquid media, and the concentrations of organic acids in the liquid media paralleled those in hairy roots. The hairy roots of I. indigotica grew fast and showed an S-shaped growth curve that reached its apex on the day 24 of culture with a 20-fold increase in fresh weight compared with the starting inoculums. The accumulation of the two organic acids CPQ and syringic acid in liquid media paralleled the growth of hairy roots. MS [Murashige, T. and Skoog, F. (1962) Physiol. Plant. 15, 473-497] medium or half-strength MS medium supplemented with 30 g/l maltose was found to be best for hairy-root culture and accumulation of CPQ.

  18. Development of a Schistosoma mansoni shotgun O-glycan microarray and application to the discovery of new antigenic schistosome glycan motifs.

    Science.gov (United States)

    van Diepen, Angela; van der Plas, Arend-Jan; Kozak, Radoslaw P; Royle, Louise; Dunne, David W; Hokke, Cornelis H

    2015-06-01

    Upon infection with Schistosoma, antibody responses are mounted that are largely directed against glycans. Over the last few years significant progress has been made in characterising the antigenic properties of N-glycans of Schistosoma mansoni. Despite also being abundantly expressed by schistosomes, much less is understood about O-glycans and antibody responses to these have not yet been systematically analysed. Antibody binding to schistosome glycans can be analysed efficiently and quantitatively using glycan microarrays, but O-glycan array construction and exploration is lagging behind because no universal O-glycanase is available, and release of O-glycans has been dependent on chemical methods. Recently, a modified hydrazinolysis method has been developed that allows the release of O-glycans with free reducing termini and limited degradation, and we applied this method to obtain O-glycans from different S. mansoni life stages. Two-dimensional HPLC separation of 2-aminobenzoic acid-labelled O-glycans generated 362 O-glycan-containing fractions that were printed on an epoxide-modified glass slide, thereby generating the first shotgun O-glycan microarray containing naturally occurring schistosome O-glycans. Monoclonal antibodies and mass spectrometry showed that the O-glycan microarray contains well-known antigenic glycan motifs as well as numerous other, potentially novel, antibody targets. Incubations of the microarrays with sera from Schistosoma-infected humans showed substantial antibody responses to O-glycans in addition to those observed to the previously investigated N- and glycosphingolipid glycans. This underlines the importance of the inclusion of these often schistosome-specific O-glycans in glycan antigen studies and indicates that O-glycans contain novel antigenic motifs that have potential for use in diagnostic methods and studies aiming at the discovery of vaccine targets. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights

  19. Metabolism of azo dyes by human skin microbiota.

    Science.gov (United States)

    Stingley, Robin L; Zou, Wen; Heinze, Thomas M; Chen, Huizhong; Cerniglia, Carl E

    2010-01-01

    Reduction of Methyl Red (MR) and Orange II (Or II) by 26 human skin bacterial species was monitored by a rapid spectrophotometric assay. The analysis indicated that skin bacteria, representing the genera Staphylococcus, Corynebacterium, Micrococcus, Dermacoccus and Kocuria, were able to reduce MR by 74-100 % in 24 h, with only three species unable to reduce completely the dye in that time. Among the species tested, only Corynebacterium xerosis was unable to reduce Or II to any degree by 24 h, and only Staphylococcus delphini, Staphylococcus sciuri subsp. sciuri and Pseudomonas aeruginosa were able to reduce completely this dye within 24 h. MR reduction started with early-exponential growth in Staphylococcus aureus and Staphylococcus epidermidis, and around late-exponential/early-stationary growth in P. aeruginosa. Reduction of Or II, Ponceau S and Ponceau BS started during late-exponential/early-stationary growth for all three species. Using liquid chromatography/electrospray ionization mass spectrometry analyses, MR metabolites produced by Staph. aureus, Staph. epidermidis and P. aeruginosa were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid. Searches of available genomic and proteomic data revealed that at least four of the staphylococci in this study, Staphylococcus haemolyticus, Staph. epidermidis, Staphylococcus cohnii and Staphylococcus saprophyticus, have hypothetical genes with 77, 76, 75 and 74 % sequence identity to azo1 encoding an azoreductase from Staph. aureus and hypothetical proteins with 82, 80, 72 and 74 % identity to Azo1, respectively. In addition, Staphylococcus capitis has a protein with 79 % identity to Azo1. Western analysis detected proteins similar to Azo1 in all the staphylococci tested, except Staph. delphini, Staph. sciuri subsp. sciuri and Staphylococcus auricularis. The data presented in this report will be useful in the risk assessment process for evaluation of public exposure to products containing these dyes.

  20. Synthesis and optical properties studies

    Directory of Open Access Journals (Sweden)

    N.A. El-Ghamaz

    2017-01-01

    Full Text Available 4-(4-Amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino-phenol (L1 and 4-(4-Amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino-benzoic acid (L2 have been synthesized by the condensation reaction of 4-aminoantipyrine (4-AAP and 4-aminophenol or 4-aminobenzoic acid in ethanolic solution and are characterized by various physico-chemical techniques. Thin films of L1 and L2 have been prepared by the conventional spin coating technique. X-ray diffraction patterns (XRD show an amorphous nature for both powder and thin films for L1 and L2 ligands. The optical absorption and refraction properties of L1 and L2 are investigated by spectrophotometric techniques at normal incidence of light in the wavelength range of 200–2500 nm. The absorption spectra show two peaks in the UV region which correspond to π → π∗ transition and a peak in UV–Vis region which may correspond to n → π∗ transition. The values of dispersion parameters Eo, Ed, εL, ε∞ and N/m* are calculated according to the single oscillator model. The presence of the OH group increases the value of ε∞ from 3.21 to 3.32 and the value of N/m* from 7.38 × 1053 to 2.08 × 1054 m−3Kg−1. The optical band transition is found to be indirect allowing fundamental energy gap values of 3.4 and 3.9 eV and onset energy gap values of 2.1 and 2.6 eV for L1 and L2, respectively.

  1. Photoisomerization of Ethyl 2–(3–Acylselenoureidothiophene– 3–carboxylates and Their Benzoanalogues

    Directory of Open Access Journals (Sweden)

    Jaromir Marek

    1997-09-01

    Full Text Available Synthesis, isomerisation and structure elucidation of the title compounds 1–6 and its isomers 7–12 by FTIR, 1H, 13C, 15N, 77Se NMR spectroscopy is reported. Ethyl 2–(3–acylselenoureidothiophene–3–carboxylates and their benzoanalogues (where acyl is benzoyl and pivaloyl were prepared by addition of ethyl 2–aminothiophene–3–carboxylates and ethyl 2–aminobenzoate on benzoyl– or pivaloylisoselenocyanate in acetone solution. An isomerization of 1–6 to the corresponding 3–acylisoselenoureas 7–12 was obtained. The isomerisation proceeds either by irradiation with light (340–400 nm or in the case of benzoylderivatives 1, 3, 5 by treatment with acetic acid. On the other hand the acid action in the pivaloyl set inhibited this isomerisation and evoked the retroisomerisation reaction of 8, 10, 12 to 2, 4, 6. Thermal analyses showed that isomerisation can be initiated also by heating. These changes proceed in the solid phase as an exothermic process at an elevated temperature but always below the temperature of melting. The structure 2 was supported by X–ray analysis. Molecular design of 2 and 8 was modeled during application of ab initio quantum chemistry calculation.

  2. Myeloperoxidase-derived oxidants induce blood-brain barrier dysfunction in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Andreas Üllen

    Full Text Available Peripheral leukocytes can exacerbate brain damage by release of cytotoxic mediators that disrupt blood-brain barrier (BBB function. One of the oxidants released by activated leukocytes is hypochlorous acid (HOCl formed via the myeloperoxidase (MPO-H2O2-Cl(- system. In the present study we examined the role of leukocyte activation, leukocyte-derived MPO and MPO-generated oxidants on BBB function in vitro and in vivo. In a mouse model of lipopolysaccharide (LPS-induced systemic inflammation, neutrophils that had become adherent released MPO into the cerebrovasculature. In vivo, LPS-induced BBB dysfunction was significantly lower in MPO-deficient mice as compared to wild-type littermates. Both, fMLP-activated leukocytes and the MPO-H2O2-Cl(- system inflicted barrier dysfunction of primary brain microvascular endothelial cells (BMVEC that was partially rescued with the MPO inhibitor 4-aminobenzoic acid hydrazide. BMVEC treatment with the MPO-H2O2-Cl(- system or activated neutrophils resulted in the formation of plasmalogen-derived chlorinated fatty aldehydes. 2-chlorohexadecanal (2-ClHDA severely compromised BMVEC barrier function and induced morphological alterations in tight and adherens junctions. In situ perfusion of rat brain with 2-ClHDA increased BBB permeability in vivo. 2-ClHDA potently activated the MAPK cascade at physiological concentrations. An ERK1/2 and JNK antagonist (PD098059 and SP600125, respectively protected against 2-ClHDA-induced barrier dysfunction in vitro. The current data provide evidence that interference with the MPO pathway could protect against BBB dysfunction under (neuroinflammatory conditions.

  3. New high-performance liquid chromatography assay for glycosyltransferases based on derivatization with anthranilic acid and fluorescence detection.

    Science.gov (United States)

    Anumula, Kalyan Rao

    2012-07-01

    Assays were developed using the unique labeling chemistry of 2-aminobenzoic acid (2AA; anthranilic acid, AA) for measuring activities of both β1-4 galactosyltransferase (GalT-1) and α2-6 sialyltransferase (ST-6) by high-performance liquid chromatography (HPLC) with fluorescence detection (Anumula KR. 2006. Advances in fluorescence derivatization methods for high-performance liquid chromatographic analysis of glycoprotein carbohydrates. Anal Biochem. 350:1-23). N-Acetylglucosamine (GlcNAc) and N-acetyllactosamine were used as acceptors and uridine diphosphate (UDP)-galactose and cytidine monophosphate (CMP)-N-acetylneuraminic acid (NANA) as donors for GalT-1 and ST-6, respectively. Enzymatic products were labeled in situ with AA and were separated from the substrates on TSKgel Amide 80 column using normal-phase conditions. Enzyme units were determined from the peak areas by comparison with the concomitantly derivatized standards Gal-β1-4GlcNAc and NANA-α2-6 Gal-β1-4GlcNAc. Linearity (time and enzyme concentration), precision (intra- and interassay) and reproducibility for the assays were established. The assays were found to be useful in monitoring the enzyme activities during isolation and purification. The assays were highly sensitive and performed equal to or better than the traditional radioactive sugar-based measurements. The assay format can also be used for measuring the activity of other transferases, provided that the carbohydrate acceptors contain a reducing end for labeling. An assay for glycoprotein acceptors was developed using IgG. A short HPLC profiling method was developed for the separation of IgG glycans (biantennary G0, G1, G2, mono- and disialylated), which facilitated the determination of GalT-1 and ST-6 activities in a rapid manner. Furthermore, this profiling method should prove useful for monitoring the changes in IgG glycans in clinical settings.

  4. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    Science.gov (United States)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  5. Gold Nanoparticle-based Surface-enhanced Raman Scattering Fe(III) Ion Sensor

    International Nuclear Information System (INIS)

    Ly, Nguyen Hoang; Joo, Sang-Woo; Cho, Kwang Hwi

    2015-01-01

    We performed density functional theory (DFT) calculations of 4-aminobenzo-15-crown-5 (4AB15C5) in conjugation with 4-mercaptobenzoic acid (4MCB) with the polarizable continuum model (PCM) while considering the aqueous media. After specific binding of the ferric ion onto the 4MCB.4AB15C5 compound, the Raman frequencies and intensities were estimated by DFT calculations with the PCM. It was predicted that the Raman intensities became significantly increased upon binding of the ferric ion. 4MCB.4AB15C5 could be assembled on gold nanoparticles (AuNPs) via the cleavage of the thiol bond. Colorimetric and UV.Vis absorption spectroscopy indicated that AuNPs became significantly aggregated in the presence of 1.10 mM of the ferric ion. Surface-enhanced Raman scattering (SERS) of 4MCB.4AB15C5 was used to identify the dissimilar spectral behaviors that yield a difference in intensity in the presence of the ferric ion. These changes were not observed in the other biological ions Zn 2+ , Mn 2+ , Fe 2+ , Na + , K + , Ca 2+ , Mg 2+ , NH 4+ , and Co 2+ . This study indicated that 4AB15C5 could be used to detect ferric ions in aqueous AuNP solutions by a combined method of colorimetric, UV.Vis absorption, and Raman spectroscopy. AuNPs.[4MCB. 4AB15C5] can thus be utilized as a selective turn-on sensor to Fe3 + in aqueous solutions above 1 mM.

  6. Profiling and characterization of sialylated N-glycans by 2D-HPLC (HIAX/PGC) with online orbitrap MS/MS and offline MSn.

    Science.gov (United States)

    Hanneman, Andrew J S; Strand, James; Huang, Chi-Ting

    2014-02-01

    Glycosylation is a critical parameter used to evaluate protein quality and consistency. N-linked glycan profiling is fundamental to the support of biotherapeutic protein manufacturing from early stage process development through drug product commercialization. Sialylated glycans impact the serum half-life of receptor-Fc fusion proteins (RFPs), making their quality and consistency a concern during the production of fusion proteins. Here, we describe an analytical approach providing both quantitative profiling and in-depth mass spectrometry (MS)-based structural characterization of sialylated RFP N-glycans. Aiming to efficiently link routine comparability studies with detailed structural characterization, an integrated workflow was implemented employing fluorescence detection, online positive and negative ion tandem mass spectrometry (MS/MS), and offline static nanospray ionization-sequential mass spectrometry (NSI-MS(n)). For routine use, high-performance liquid chromatography profiling employs established fluorescence detection of 2-aminobenzoic acid derivatives (2AA) and hydrophilic interaction anion-exchange chromatography (HIAX) charge class separation. Further characterization of HIAX peak fractions is achieved by online (-) ion orbitrap MS/MS, offering the advantages of high mass accuracy and data-dependent MS/MS. As required, additional characterization uses porous graphitized carbon in the second chromatographic dimension to provide orthogonal (+) ion MS/MS spectra and buffer-free liquid chromatography peak eluants that are optimum for offline (+)/(-) NSI-MS(n) investigations to characterize low-abundance species and specific moieties including O-acetylation and sulfation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  7. Biodegradation of methyl red by Bacillus sp. strain UN2: decolorization capacity, metabolites characterization, and enzyme analysis.

    Science.gov (United States)

    Zhao, Ming; Sun, Peng-Fei; Du, Lin-Na; Wang, Guan; Jia, Xiao-Ming; Zhao, Yu-Hua

    2014-05-01

    Azo dyes are recalcitrant and refractory pollutants that constitute a significant menace to the environment. The present study is focused on exploring the capability of Bacillus sp. strain UN2 for application in methyl red (MR) degradation. Effects of physicochemical parameters (pH of medium, temperature, initial concentration of dye, and composition of the medium) were studied in detail. The suitable pH and temperature range for MR degradation by strain UN2 were respectively 7.0-9.0 and 30-40 °C, and the optimal pH value and temperature were respectively 8.0 and 35 °C. Mg(2+) and Mn(2+) (1 mM) were found to significantly accelerate the MR removal rate, while the enhancement by either Fe(3+) or Fe(2+) was slight. Under the optimal degradation conditions, strain UN2 exhibited greater than 98 % degradation of the toxic azo dye MR (100 ppm) within 30 min. Analysis of samples from decolorized culture flasks confirmed biodegradation of MR into two prime metabolites: N,N'dimethyl-p-phenyle-nediamine and 2-aminobenzoic acid. A study of the enzymes responsible for the biodegradation of MR, in the control and cells obtained during (10 min) and after (30 min) degradation, showed a significant increase in the activities of azoreductase, laccase, and NADH-DCIP reductase. Furthermore, a phytotoxicity analysis demonstrated that the germination inhibition was almost eliminated for both the plants Triticum aestivum and Sorghum bicolor by MR metabolites at 100 mg/L concentration, yet the germination inhibition of parent dye was significant. Consequently, the high efficiency of MR degradation enables this strain to be a potential candidate for bioremediation of wastewater containing MR.

  8. Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes

    International Nuclear Information System (INIS)

    Holm, Allan Hjarbaek; Vase, Karina Hojrup; Winther-Jensen, Bjorn; Pedersen, Steen Uttrup; Daasbjerg, Kim

    2007-01-01

    The hydroquinone/quinone (H 2 Q/Q) redox system was tethered to glassy carbon surfaces using first an electrochemical pre-oxidation treatment to afford carboxylic acid functionalities followed by immobilizing the H 2 Q precursor, n-(2,5-dimethoxyphenyl)alkan-1-amine (general structure: H 2 N-(CH 2 ) n -C 6 H 3 (OCH 3 ) 2 , n = 1, 2, 4, 8, and 12), by carbodiimide chemistry and a final demethylation reaction. The resultant surfaces exhibited the expected chemical reversibility in aqueous solution with a pH-sensitive position of the formal potential (∼55 mV/pH unit), and an increase in the peak potential separation going from 0.02 V for n = 1 to 0.21 V for n = 12. The films were very robust and could withstand prolonged sonication and relatively large potential excursions. While the films followed the expected kinetic distance dependence for up to 4 methylene units the electrode kinetics was faster than expected for longer alkyl spacers. We suggest that film disorder, electrode-mediating effects, and a roughened electrode material could account for these apparent inconsistencies. To further understand such effects, two complementary electrode modification strategies leading to better film ordering on carbon were adapted; immobilizing a thin layer of benzoic acid by oxidative deposition of 4-aminobenzoic acid or employing a plasma deposition process to tether an acid analogue. Analysis of the various electrodes was accomplished by electrochemical methods, atomic force microscopy, and X-ray photoelectron spectroscopy

  9. Inhibition of PCAF histone acetyltransferase, cytotoxicity and cell permeability of 2-acylamino-1-(3- or 4-carboxy-phenyl)benzamides.

    Science.gov (United States)

    Park, Woong Jae; Ma, Eunsook

    2012-11-05

    Small molecule HAT inhibitors are useful tools to unravel the role of histone acetyltransferases (HATs) in the cell and they also have relevance in oncology. We synthesized a series of 2-acylamino-1-(3- or 4-carboxyphenyl)benzamides 8–19 bearing C6, C8, C10, C12, C14, and C16 acyl chains at the 2-amino position of 2-aminobenzoic acid. Enzyme inhibition of these compounds was investigated using in vitro PCAF HAT assays. The inhibitory activities of compounds 8–10, 16, and 19 were similar to that of anacardic acid, and 17 was found to be more active than anacardic acid at 100 μM. Compounds 11–15 showed the low inhibitory activity on PCAF HAT. The cytotoxicity of the synthesized compounds was evaluated by SRB (sulforhodamine B) assay against seven human cancer cell lines: HT-29 (colon), HCT-116 (colon), MDA-231 (breast), A549 (lung), Hep3B (hepatoma), HeLa (cervical) and Caki (kidney) and one normal cell line (HSF). Compound 17 was more active than anacardic acid against human colon cancer (HCT 116, IC(50): 29.17 μM), human lung cancer (A549, IC₅₀: 32.09 μM) cell lines. 18 was more active than anacardic acid against human colon cancer (HT-29, IC₅₀: 35.49 μM and HCT 116, IC₅₀: 27.56 μM), human lung cancer (A549, IC₅₀: 30.69 μM), and human cervical cancer (HeLa, IC₅₀: 34.41 μM) cell lines. The apparent permeability coefficient (P(app), cm/s) values of two compounds (16 and 17) were evaluated as 68.21 and 71.48 × 10⁻⁶ cm/s by Caco-2 cell permeability assay.

  10. Analytical characterization of ch14.18

    Science.gov (United States)

    Kallarakal, Abraham T; Michiel, Dennis; Yang, Xiaoyi; Saptharishi, Nirmala; Jiang, Hengguang; Giardina, Steve; Gilly, John; Mitra, George

    2012-01-01

    Ch14.18 is a mouse-human chimeric monoclonal antibody to the disialoganglioside (GD2) glycolipid. In the clinic, this antibody has been shown to be effective in the treatment of children with high-risk neuroblastoma, either alone or in combination therapy. Extensive product characterization is a prerequisite to addressing the potential issues of product variability associated with process changes and manufacturing scale-up. Charge heterogeneity, glycosylation profile, molecular state and aggregation, interaction (affinity) with Fcγ receptors and functional or biological activities are a few of the critical characterization assays for assessing product comparability for this antibody. In this article, we describe the in-house development and qualification of imaged capillary isoelectric focusing to assess charge heterogeneity, analytical size exclusion chromatography with online static and dynamic light scattering (DLS), batch mode DLS for aggregate detection, biosensor (surface plasmon resonance)-based Fcγ receptor antibody interaction kinetics, N-glycoprofiling with PNGase F digestion, 2-aminobenzoic acid labeling and high performance liquid chromatography and N-glycan analysis using capillary electrophoresis. In addition, we studied selected biological activity assays, such as complement-dependent cytotoxicity. The consistency and reproducibility of the assays are established by comparing the intra-day and inter-day assay results. Applications of the methodologies to address stability or changes in product characteristics are also reported. The study results reveal that the ch14.18 clinical product formulated in phosphate-buffered saline at a concentration of 5 mg/ml and stored at 2–8°C is stable for more than five years. PMID:22327432

  11. Stable isotopic labeling-based quantitative targeted glycomics (i-QTaG).

    Science.gov (United States)

    Kim, Kyoung-Jin; Kim, Yoon-Woo; Kim, Yun-Gon; Park, Hae-Min; Jin, Jang Mi; Hwan Kim, Young; Yang, Yung-Hun; Kyu Lee, Jun; Chung, Junho; Lee, Sun-Gu; Saghatelian, Alan

    2015-01-01

    Mass spectrometry (MS) analysis combined with stable isotopic labeling is a promising method for the relative quantification of aberrant glycosylation in diseases and disorders. We developed a stable isotopic labeling-based quantitative targeted glycomics (i-QTaG) technique for the comparative and quantitative analysis of total N-glycans using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We established the analytical procedure with the chemical derivatizations (i.e., sialic acid neutralization and stable isotopic labeling) of N-glycans using a model glycoprotein (bovine fetuin). Moreover, the i-QTaG using MALDI-TOF MS was evaluated with various molar ratios (1:1, 1:2, 1:5) of (13) C6 /(12) C6 -2-aminobenzoic acid-labeled glycans from normal human serum. Finally, this method was applied to direct comparison of the total N-glycan profiles between normal human sera (n = 8) and prostate cancer patient sera (n = 17). The intensities of the N-glycan peaks from i-QTaG method showed a good linearity (R(2) > 0.99) with the amount of the bovine fetuin glycoproteins. The ratios of relative intensity between the isotopically 2-AA labeled N-glycans were close to the theoretical molar ratios (1:1, 1:2, 1:5). We also demonstrated that the up-regulation of the Lewis antigen (~82%) in sera from prostate cancer patients. In this proof-of-concept study, we demonstrated that the i-QTaG method, which enables to achieve a reliable comparative quantitation of total N-glycans via MALDI-TOF MS analysis, has the potential to diagnose and monitor alterations in glycosylation associated with disease states or biotherapeutics. © 2015 American Institute of Chemical Engineers.

  12. Capillary electrophoresis determination of glucosamine in nutraceutical formulations after labeling with anthranilic acid and UV detection.

    Science.gov (United States)

    Volpi, Nicola

    2009-04-05

    A new robust CE method for the determination of the glucosamine (GlcN) content in nutraceutical formulations is described after its derivatization with anthranilic acid (2-aminobenzoic acid, AA). The CE separation of derivatized GlcN with AA was performed on an uncoated fused-silica capillary tube (50 microm I.D.) using an operating pH 7.0 buffer of 150 mM boric acid/50 mM NaH2PO4 and UV detection at 214 nm. The method was validated for specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). The detector response for GlcN was linear over the selected concentration range from 240 to 2400 pg (40-400 microg/mL) with a correlation coefficient greater than 0.980. The intra- and inter-day variations (CV%) were between 0.5 and 0.9 for migration time, and between 2.8 and 4.3 for peak area, respectively. The LOD and the LOQ of the method were approximately 200 and 500 pg, respectively. The intra- and inter-day accuracy was estimated to range from 2.8% to 5.1%, while the percent recoveries of GlcN in formulations were calculated to be about 100% after simple centrifugation for 10 min, lyophilization and derivatization with AA. The CE method was applied to the determination of GlcN content, in the form of GlcN-hydrochloride or GlcN-sulfate, of several nutraceutical preparations in the presence of other ingredients, i.e. chondroitin sulfate, vitamin C and/or methylsulfonylmethane (MSM) as well as salts and other agents. The quantitative results obtained were in total conformity with the label claims.

  13. Inhibition of PCAF Histone Acetyltransferase, Cytotoxicity and Cell Permeability of 2-Acylamino-1-(3- or 4-Carboxy-phenylbenzamides

    Directory of Open Access Journals (Sweden)

    Eunsook Ma

    2012-11-01

    Full Text Available Small molecule HAT inhibitors are useful tools to unravel the role of histone acetyltransferases (HATs in the cell and they also have relevance in oncology. We synthesized a series of 2-acylamino-1-(3- or 4-carboxyphenylbenzamides 8–19 bearing C6, C8, C10, C12, C14, and C16 acyl chains at the 2-amino position of 2-aminobenzoic acid. Enzyme inhibition of these compounds was investigated using in vitro PCAF HAT assays. The inhibitory activities of compounds 8–10, 16, and 19 were similar to that of anacardic acid, and 17 was found to be more active than anacardic acid at 100 μM. Compounds 11–15 showed the low inhibitory activity on PCAF HAT. The cytotoxicity of the synthesized compounds was evaluated by SRB (sulforhodamine B assay against seven human cancer cell lines: HT-29 (colon, HCT-116 (colon, MDA-231 (breast, A549 (lung, Hep3B (hepatoma, HeLa (cervical and Caki (kidney and one normal cell line (HSF. Compound 17 was more active than anacardic acid against human colon cancer (HCT 116, IC50: 29.17 μM, human lung cancer (A549, IC50: 32.09 μM cell lines. 18 was more active than anacardic acid against human colon cancer (HT-29, IC50: 35.49 μM and HCT 116, IC50: 27.56 μM, human lung cancer (A549, IC50: 30.69 μM, and human cervical cancer (HeLa, IC50: 34.41 μM cell lines. The apparent permeability coefficient (Papp, cm/s values of two compounds (16 and 17 were evaluated as 68.21 and 71.48 × 10−6 cm/s by Caco-2 cell permeability assay.

  14. Characterization of kallikrein-related peptidase 4 glycosylations.

    Science.gov (United States)

    Yamakoshi, Yasuo; Yamakoshi, Fumiko; Hu, Jan C-C; Simmer, James P

    2011-12-01

    Kallikrein-related peptidase 4 (KLK4) is a glycosylated serine protease that functions in the maturation (hardening) of dental enamel. Pig and mouse KLK4 contain three potential N-glycosylation sites. We isolated KLK4 from developing pig and mouse molars and characterized their N-glycosylations. N-glycans were enzymatically released by digestion with N-glycosidase F and fluorescently labeled with 2-aminobenzoic acid. Normal-phase high-performance liquid chromatography (NP-HPLC) revealed N-glycans with no, or with one, two, or three sialic acid attachments in pig KLK4 and with no, or with one or two sialic acid attachments in mouse KLK4. The labeled N-glycans were digested with sialidase to generate the asialo N-glycan cores that were fractionated by reverse-phase HPLC, and their retention times were compared with similarly labeled glycan standards. The purified cores were characterized by mass spectrometric and monosaccharide composition analyses. We determined that pig and mouse KLK4 have NA2 and NA2F biantennary N-glycan cores. The pig triantennary core is NA3. The mouse triantennary core is NA3 with a fucose connected by an α1-6 linkage, indicating that it is attached to the first N-acetyglucosamine (NA3F). We conclude that pig KLK4 has NA2, NA2F, and NA3 N-glycan cores with no, or with one, two, or three sialic acids. Mouse KLK4 has NA2, NA2F, and NA3F N-glycan cores with no, or with one or two sialic acids. © 2011 Eur J Oral Sci.

  15. Cyclometalation and coupling of a rigid 4,5-bis(imino)acridanide pincer ligand on yttrium.

    Science.gov (United States)

    Wong, Edwin W Y; Emslie, David J H

    2015-07-07

    An extremely rigid NNN-donor proligand, 4,5-bis{(diphenylmethylene)amino}-2,7,9,9-tetramethylacridan, H[AIm2] was prepared in five steps starting from 5-methyl-2-aminobenzoic acid and 4-bromotoluene. Reaction of intensely orange H[AIm2] with LiCH2SiMe3 formed deep blue Li(x)[AIm2]x (x = 2 in the solid state), while reaction with [Y(CH2SiMe3)3(THF)2] (0.5 equiv.) afforded deep blue [Y(AIm2)(AIm)] (1; AIm = an AIm2 ligand cyclometalated at the ortho-position of one of the phenyl rings). Compound 1 slowly isomerizes to form green-brown 2, which contains a single trianionic, hexadentate ligand that features one amine, two imine, and three amido donors. The acridanide backbone and one imine group in each of the original AIm2 ligands is intact, but the two acridanide backbones are now linked by an isoindoline heterocycle. Yttrium in 2 is coordinated to six nitrogen donors and the ortho carbon of an isoindoline phenyl substituent. The intense colours of H[AIm2], Li(x)[AIm2]x and 1 were shown by TD-DFT calculations to arise from charge transfer transitions from the HOMO, which is localized on the acridanide ligand backbone, to the LUMO and LUMO+1, which are localized on the imine substituents. The conversion of 1 to 2 was studied by UV-Visible absorption spectroscopy and is first-order with a half-life of 7.8 hours at room temperature.

  16. Functional polyaniline nanofibre mats for human adipose-derived stem cell proliferation and adhesion

    International Nuclear Information System (INIS)

    Abdul Rahman, Norizah; Feisst, Vaughan; Dickinson, Michelle E.; Malmström, Jenny; Dunbar, P. Rod; Travas-Sejdic, Jadranka

    2013-01-01

    Conductive polymer poly(aniline-co-m-aminobenzoic acid) (P(ANI-co-m-ABA)) and polyaniline (PANI) were blended with a biodegradable, biocompatible polymer, poly(L-lactic acid) and were electrospun into nanofibres to investigate their potential application as a scaffold for human adipose-derived stem cells (hASCs). These polymers, in both conductive and non-conductive form, were electrospun with average fibre diameters of less than 400 nm. Novel nanoindentation results obtained on the individual nanofibres revealed that the elastic moduli of the nanofibres are much higher at the surface (4–10 GPa, h max max >75 nm). The composite nanofibres showed great promise as a scaffold for hASCs as they supported the cell adhesion and proliferation. After 1 week of cell culture hASCs were well spread on the substrates with abundant focal adhesions. The electrospun mats provide the cells with comparably stiff, sub-micron sized fibres as anchoring points on a substrate of high porosity. The conductive nature of these composite nanofibres offers exciting opportunities for electrical stimulation of the cells. - Highlights: ► Polyaniline and its copolymer's nanofibres were prepared by electrospinning. ► The elastic modulus of a single polyaniline composite nanofibres were determined. ► Elastic moduli of the nanofibres are much higher at the surface than the inner core. ► The electrospun mats supported the cell adhesion and proliferation. ► The nanofibres show great promise as a scaffold for adipose derived stem cells

  17. A photoaffinity ligand for dopamine D2 receptors: azidoclebopride.

    Science.gov (United States)

    Niznik, H B; Guan, J H; Neumeyer, J L; Seeman, P

    1985-02-01

    In order to label D2 dopamine receptors selectively and covalently by means of a photosensitive compound, azidoclebopride was synthesized directly from clebopride. The dissociation constant (KD) of clebopride for the D2 dopamine receptor (canine brain striatum) was 1.5 nM, while that for azidoclebopride was 21 nM. The affinities of both clebopride and azidoclebopride were markedly reduced in the absence of sodium chloride. In the presence of ultraviolet light, azidoclebopride inactivated D2 dopamine receptors irreversibly, as indicated by the inability of the receptors to bind [3H]spiperone. Maximal photoinactivation of about 60% of the D2 dopamine receptors occurred at 1 microM azidoclebopride; 30% of the receptors were inactivated at 80 nM azidoclebopride (pseudo-IC50). Dopamine agonists selectively protected the D2 receptors from being inactivated by azidoclebopride, the order of potency being (-)-N-n-propylnorapomorphine greater than apomorphine greater than (+/-)-6,7-dihydroxy-2-aminotetralin greater than (+)-N-n-propylnorapomorphine greater than dopamine greater than noradrenaline greater than serotonin. Similarly, dopaminergic antagonists prevented the photoinactivation of D2 receptors by azidoclebopride with the following order of potency: spiperone greater than (+)-butaclamol greater than haloperidol greater than clebopride greater than (-)-sulpiride greater than (-)-butaclamol. The degree of D2 dopamine receptor photoinduced inactivation by azidoclebopride was not significantly affected by scavengers such as p-aminobenzoic acid and dithiothreitol. Furthermore, irradiation of striatal membranes with a concentration of azidoclebopride sufficient to inactivate dopamine D2 receptors by 60% did not significantly reduce dopamine D1, serotonin (S2), benzodiazepine, alpha 1- or beta-noradrenergic receptors. This study describes the use of a novel and selective photoaffinity ligand for brain dopamine D2 receptors. The molecule, in radiolabeled form, may aid in the

  18. The magnetorheological fluid of carbonyl iron suspension blended with grafted MWCNT or graphene

    Science.gov (United States)

    Rwei, Syang-Peng; Ranganathan, Palraj; Chiang, Whe-Yi; Wang, Tza-Yi

    2017-12-01

    In this work, the magnetorheological (MR) fluids containing MWCNT/CI (carbonyl iron) complex and graphene/CI complex were prepared and have the better dispersity in silicone oil than CI powders alone. 1, 4-Aminobenzoic acid (PABA) was used as a grafting agent to modify CI powders to have NH2-end-group so that such nanoparticles can adsorb to acid-treated MWCNT or graphene via attraction of NH2 and COOH groups. The MWCNT/CI complex and graphene/CI complex have a structure of carbonyl iron nanoparticles adsorbed to MWCNT and graphene by self assembly, respectively. Because the carbonyl iron particles possessing magnetic permeability in nanometer scale adsorb to MWCNT or graphene which usually has a nanometer-scaled diameter and a micrometer-scaled length in this work, the dispersity of MWCNT/CI or graphene/CI complex in silicone oil is superior than the previous report [15] that the micrometer-scaled carbonyl iron microspheres were coated with multiwalled carbon nanotubes. Among CI (unmodified), MWCNT/CI and graphene/CI, graphene/CI has the best dispersity while MWCNT/CI still has the better dispersity than unmodified CI. At the temperature T = 300 K, the saturation magnetizations of CI, MWCNT/CI, graphene/CI are 208, 211 emu/g, and 204 emu/g, respectively, indicating that MWCNT/CI complex and graphene/CI complex still maintain the saturation magnetization as high as CI without being interfered by the blended MWCNT or graphene. A wide dynamic range of the yield stress adjusted through varying the electric current can be achieved by the MR fluids containing 69 wt% MWCNT/CI and graphene/CI which is useful in a shock absorber or damper. The result of the yield stress indicates the suspended MWCNT/CI particles are oriented more easily toward the direction perpendicular to the flow direction to block the flow stream lines.

  19. Folate Production by Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Stefano Raimondi

    2011-01-01

    Full Text Available Probiotic bacteria, mostly belonging to the genera Lactobacillus and Bifidobacterium, confer a number of health benefits to the host, including vitamin production. With the aim to produce folate-enriched fermented products and/or develop probiotic supplements that accomplish folate biosynthesis in vivo within the colon, bifidobacteria and lactobacilli have been extensively studied for their capability to produce this vitamin. On the basis of physiological studies and genome analysis, wild-type lactobacilli cannot synthesize folate, generally require it for growth, and provide a negative contribution to folate levels in fermented dairy products. Lactobacillus plantarum constitutes an exception among lactobacilli, since it is capable of folate production in presence of para-aminobenzoic acid (pABA and deserves to be used in animal trials to validate its ability to produce the vitamin in vivo. On the other hand, several folate-producing strains have been selected within the genus Bifidobacterium, with a great variability in the extent of vitamin released in the medium. Most of them belong to the species B. adolescentis and B. pseudocatenulatum, but few folate producing strains are found in the other species as well. Rats fed a probiotic formulation of folate-producing bifidobacteria exhibited increased plasma folate level, confirming that the vitamin is produced in vivo and absorbed. In a human trial, the same supplement raised folate concentration in feces. The use of folate-producing probiotic strains can be regarded as a new perspective in the specific use of probiotics. They could more efficiently confer protection against inflammation and cancer, both exerting the beneficial effects of probiotics and preventing the folate deficiency that is associated with premalignant changes in the colonic epithelia.

  20. Synthesis and in Vitro and in Vivo Anticoagulant and Antiplatelet Activities of Amidino- and Non-Amidinobenzamides

    Directory of Open Access Journals (Sweden)

    Soo Hyun Lee

    2016-05-01

    Full Text Available Three amidino- and ten non-amidinobenzamides were synthesized as 3-aminobenzoic acid scaffold-based anticoagulant and antiplatelet compounds. The anticoagulant activities of thirteen synthesized compounds 1–13, and 2b and 3b as prodrugs were preliminary evaluated by screening the prolongation of activated partial thromboplastin time (aPTT and prothrombin time (PT in vitro. From the aPTT results obtained, two amidinobenzamides, N-(3′-amidinophenyl-3-(thiophen-2′′-ylcarbonylamino benzamide (1, 33.2 ± 0.7 s and N-(4′-amidinophenyl-3-(thiophen-2′′-ylcarbonylamino benzamide (2, 43.5 ± 0.6 s were selected to investigate the further anticoagulant and antiplatelet activities. The aPTT results of 1 (33.2 ± 0.7 s and 2 (43.5 ± 0.6 s were compared with heparin (62.5 ± 0.8 s in vitro at 30 μM. We investigated the effect of 1 and 2 on blood anticoagulant activity (ex vivo and on tail bleeding time (in vivo on mice. A tail cutting/bleeding time assay revealed that both 1 and 2 prolonged bleeding time in mice at a dose of 24.1 g/mouse and above. Compounds 1 and 2 dose-dependently inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In addition, 1 and 2 were evaluated on the inhibitory activities of thrombin and FXa as well as the generation of thrombin and FXa in human umbilical vein endothelial cells (HUVECs. Collectively, 1 and 2 possess some antiplatelet and anticoagulant activities and offer a basis for development of a novel antithrombotic product.

  1. Synthesis and characterization of hybrid carbon nanotube/polymer for use in the active layer of organic solar cells'

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Luiza De Lazari; Calado, Hallen Daniel Rezende, E-mail: luizadl@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2016-07-01

    Full text: Nowadays, the fast development of portable and flexible devices such as smart phones, smart watches and adhesive sensors, has stimulated research into alternative energy generators for the operation of these devices. Organic solar cells (OPVs) are seen as a promising technology in this scenario because their properties such as low weight, semi-transparency, low cost and flexibility. Intrinsically conducting polymers (CPs) are studied as active layer in OPVs because their good electrical and optical properties. The carbon nanotube - CNT in the polymer matrix leads to the formation of interconnected nano networks influencing the crystalline CP behavior and reducing the resistance in the charge transfer. This increases the transport of electrons and minimizes recombination by p-p and p-CH{sub 2} interaction with CPs, enhancing its properties and improving the efficiency of OPVs optoelectronics. To preparing the hybrid for this work in 3 stages it was used a homemade multi-walled CNT. Initially, the CNT's were functionalized with amine 1,3-diaminopropane - DAP (CNT-DAP) and then with an amine monomer from p-aminobenzoic acid - ABA. In a subsequent step, the hybrid (CNT-DAP-ABA-P3HT) was obtained by polymerizing using FeCl{sub 3} 3- hexylthiophene (3HT) in the presence of NTC-DAP-ABA, which led to obtaining the PC directly connected to CNT. The resulting hybrid was characterized by FTIR, Raman, XPS, thermal analysis, SEM, optical absorption and fluorescence. FTIR spectra showed bands associated with functional groups present in the functionalization steps. Raman results showed the increase of the ratio ID/IG caused by greater disorder by inserting the new groups to the CNT. The electrochemical profile was studied by cyclic voltammetry at different scan rates, generating curves with almost reversible profile. The analyzes showed that the CNT were functionalized covalently and have potential for application in active layer of OPVs. (author)

  2. LC/MS/MS identification of some folic acid degradation products after E-beam irradiation

    International Nuclear Information System (INIS)

    Araújo, M.M.; Marchioni, E.; Zhao, M.; Kuntz, F.; Di Pascoli, T.; Villavicencio, A.L.C.H.; Bergaentzle, M.

    2012-01-01

    Folates belong to the B vitamin group based on the parental compound folic acid (FA). They are involved in important biochemical processes like DNA synthesis and repair. FA is composed of a pteridine ring, p-aminobenzoic acid and glutamate moieties. The human metabolism is not able to synthesize folates and therefore obtain them from diet. FA, a synthetic vitamin, is used as a food fortificant because of its low price, relative stability and increased bioavailability compared to natural folate forms. FA is known to be a sensitive compound easily degradable in aqueous solution by ultraviolet and visible light towards various by-products. Irradiation is a process for preservation of foods that uses accelerated electrons, gamma rays or X-rays. Irradiation is proposed for the treatment of various food products, eliminating or reducing pathogens and insects, increasing the storage time and replacing chemical fumigants. This study concerns the identification of degradation products of FA after E-beam irradiation. FA aqueous solutions were irradiated with a Van de Graaff electrons beam accelerator (2 MeV, 100 μA current, 20 cm scan width, dose rate about 2 kGy/s). Applied doses were between 0 (control) and 10.0 kGy. Absorbed doses were monitored with FWT 60.00 radiochromic dosimeters. - Highlights: ► We investigated the degradation of folic acid aqueous solution after electron beam treatment. ► Radiation doses over 5 kGy promote huge folic acid degradation and appearance of several degradation products. ► PCA, PABA and pABGA, already known folic acid degradation products, are formed due to E-beam treatment. ► Xanthopterin, a new radio-induced breakdown product, is formed after irradiation treatment.

  3. Contamination sources and distribution patterns of pharmaceuticals and personal care products in Alpine rivers strongly affected by tourism.

    Science.gov (United States)

    Mandaric, Ladislav; Diamantini, Elena; Stella, Elisa; Cano-Paoli, Karina; Valle-Sistac, Jennifer; Molins-Delgado, Daniel; Bellin, Alberto; Chiogna, Gabriele; Majone, Bruno; Diaz-Cruz, M Silvia; Sabater, Sergi; Barcelo, Damia; Petrovic, Mira

    2017-07-15

    Knowledge regarding the impact of tourism on the emergence of pharmaceuticals and personal care products (PPCPs) in Alpine river waters is limited and scarce. Therefore, a study on the occurrence patterns and spatiotemporal variability of 105 PPCPs in an Alpine river basin located in the Trentino-Alto Adige region (North-Eastern Italy) has been conducted. We observed that the total concentration of analyzed PPCPs was generally higher in all sampling sites during winter than in the summer. The analysis of tourist data revealed that during both sampling campaigns the number of tourists was lower in the downstream sites in comparison with the upstream area of the basin (Val di Sole). Particularly, sampling sites located near important tourist resorts have shown the highest abundance of the PPCPs during winter, being analgesics/anti-inflammatories, antihypertensives and antibiotics the most abundant pharmaceutically active compounds (PhACs). Diclofenac showed the highest concentration amongst PhACs, reaching concentrations up to 675ngL -1 in the sampling site situated downstream of the Tonale wastewater treatment plant (WWTP). Antihypertensives were found at concentrations >300ngL -1 , while antibiotics were quantified up to 196ngL -1 , respectively. Amongst personal care products (PCPs), the most abundant compound was octyl-dimethyl-p-aminobenzoic acid (ODPABA) with concentrations reaching up to 748ngL -1 in the sampling site situated within the Rotaliana district. In general, concentrations and detection frequencies were higher in water than in the sediment samples. The most frequently detected PhACs in sediments from both sampling campaigns were antibiotics, while amongst PCPs in sediments, octocrylene (OC) showed the highest concentration in both sampling campaigns. As a result, this study highlights the potential impact of tourism on the water quality of the Alpine aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Photophysical studies of highly luminescent europium(III) and terbium(III) complexes functionalized with amino and mercapto groups

    Energy Technology Data Exchange (ETDEWEB)

    Souza, E.R.; Monteiro, J.H.S.K.; Mazali, I.O.; Sigoli, F.A., E-mail: fsigoli@iqm.unicam.br

    2016-02-15

    This work proposes the replacement of coordinated-water molecules from the precursor complexes [Ln(aba){sub 3}(H{sub 2}O)] and [Ln(tta){sub 3}(H{sub 2}O){sub 2}], (Ln=Eu{sup 3+}, Gd{sup 3+} or Tb{sup 3+}, aba{sup −}=aminobenzoate, tta{sup −}=thenoyltrifluoroacetonate) by the ligands mercaptobenzoate (mba{sup −}), mercaptopropionate (mpa{sup −}), phenanthroline (phen), dimethylformamide (dmf) and acetoacetanilide (aaa{sup −}), leading to anionic or neutral amino (–NH{sub 2}) or mercapto (–SH) functionalized-lantanides (III) complexes with reasonable emission quantum yields for potential application on fluorescence microscopy of biological moieties. The complexes photophysical properties were studied using luminescence spectroscopy and theoretical models to determine the transfer and back energy transfer rates and quantum yields, that were compared with experimental ones. The anionic complexes [Eu(tta){sub 3}(L)]{sup −} showed high quantum yield values and their sensitization efficiency are in the range of 39–81%. The overlay of the ground state geometries, obtained from the Sparkle/PM3 model, of the complexes [Eu(tta){sub 3}(aba)]{sup −}, [Eu(tta){sub 3}(mba)]{sup −} and [Eu(tta){sub 3}(mpa)]{sup −}, suggest similar coordination polyhedrons occupied by the europium(III). The highest transfer rates T→{sup 5}D{sub 1,0} were obtained for the anionic complexes [Eu(tta){sub 3}(L)]{sup −} which might be a result of the low triplet level energies and R{sub L} values. - Highlights: • Lanthanides functionalized-complexes. • Free mercapto and amino groups. • Covalence degree of Eu-ligands. • Energy transfer rates. • Intrinsic and absolute quantum yields and sensitization.

  5. Functionalization of glassy carbon surface by means of aliphatic and aromatic amino acids. An experimental and theoretical integrated approach

    International Nuclear Information System (INIS)

    Vanossi, Davide; Benassi, Rois; Parenti, Francesca; Tassinari, Francesco; Giovanardi, Roberto; Florini, Nicola; De Renzi, Valentina; Arnaud, Gaelle; Fontanesi, Claudio

    2012-01-01

    Highlights: ► Glassy carbon is functionalized via electrochemical assisted grafting of amino acids. ► The grafting mechanism is suggested to involve the “zwitterionic” species. ► DFT calculations allowed to determine the electroactive species. ► An original grafting mechanism is proposed. - Abstract: Glassy carbon (GC) electrode surfaces are functionalized through electrochemical assisted grafting, in oxidation regime, of six amino acids (AA): β-alanine (β-Ala), L-aspartic acid (Asp), 11-aminoundecanoic acid (UA), 4-aminobenzoic acid (PABA), 4-(4-amino-phenyl)-butyric acid (PFB), 3-(4-amino-phenyl)-propionic acid (PFP). Thus, a GC/AA interface is produced featuring carboxylic groups facing the solution. Electrochemical (cyclic voltammetry and electrochemical impedance spectroscopy) and XPS techniques are used to experimentally characterize the grafting process and the surface state. The theoretical results are compared with the experimental evidence to determine, at a molecular level, the overall grafting mechanism. Ionization potentials, standard oxidation potentials, HOMO and electron spin distributions are calculated at the CCD/6-31G* level of the theory. The comparison of experimental and theoretical data suggests that the main electroactive species is the “zwitterionic” form for the three aliphatic amino acids, while the amino acids featuring the amino group bound to the phenyl aromatic moiety show a different behaviour. The comparison between experimental and theoretical results suggests that both the neutral and the zwitterionic forms are present in the acetonitrile solution in the case of 4-(4-amino-phenyl)-butyric acid (PFB) and 3-(4-amino-phenyl)-propionic acid.

  6. Pseudomonas aeruginosa 4-amino-4-deoxychorismate lyase: spatial conservation of an active site tyrosine and classification of two types of enzyme.

    Directory of Open Access Journals (Sweden)

    Patrick E F O'Rourke

    Full Text Available 4-Amino-4-deoxychorismate lyase (PabC catalyzes the formation of 4-aminobenzoate, and release of pyruvate, during folate biosynthesis. This is an essential activity for the growth of gram-negative bacteria, including important pathogens such as Pseudomonas aeruginosa. A high-resolution (1.75 Å crystal structure of PabC from P. aeruginosa has been determined, and sequence-structure comparisons with orthologous structures are reported. Residues around the pyridoxal 5'-phosphate cofactor are highly conserved adding support to aspects of a mechanism generic for enzymes carrying that cofactor. However, we suggest that PabC can be classified into two groups depending upon whether an active site and structurally conserved tyrosine is provided from the polypeptide that mainly forms an active site or from the partner subunit in the dimeric assembly. We considered that the conserved tyrosine might indicate a direct role in catalysis: that of providing a proton to reduce the olefin moiety of substrate as pyruvate is released. A threonine had previously been suggested to fulfill such a role prior to our observation of the structurally conserved tyrosine. We have been unable to elucidate an experimentally determined structure of PabC in complex with ligands to inform on mechanism and substrate specificity. Therefore we constructed a computational model of the catalytic intermediate docked into the enzyme active site. The model suggests that the conserved tyrosine helps to create a hydrophobic wall on one side of the active site that provides important interactions to bind the catalytic intermediate. However, this residue does not appear to participate in interactions with the C atom that undergoes an sp(2 to sp(3 conversion as pyruvate is produced. The model and our comparisons rather support the hypothesis that an active site threonine hydroxyl contributes a proton used in the reduction of the substrate methylene to pyruvate methyl in the final stage of

  7. Enhanced biodegradation of petrochemical wastewater using ozonation and BAC advanced treatment system

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chi-Kang; Tsai, Tsung-Yueh; Liu, Jiunn-Ching; Chen, Mei-Chen [Energy and Resources Labs., ITRI, Hsinchu (Taiwan)

    2001-07-01

    The characteristics of degradation/conversion of bio-refractory and the growth of a biofilm are investigated in laboratory-scale pre-ozonation and lifted moving-bed biological activated carbon (BAC) advanced treatment processes treating phenol, benzoic acid, aminobenzoic acid and petrochemical industry wastewater which contains acrylonitrile butadiene styrene (ABS). The optimal reaction time and ozone dosage of pre-ozonation for bio-refractory conversion were determined to be 30 min and 100-200mg O{sub 3}/hr, respectively. After pre-ozonation of 30 min treatment, BOD{sub 5}/COD ratio of influent and effluent increased apparently from 20 to 35%, approximately. However, the change of pH in pre-ozonation was inconspicuous. The optimal flow rate of influent and air were controlled at 1.6 1/h and 120-l50nl/min in lifted moving-bed BAC advanced treatment reactor. A COD removal efficiency of 85-95% and 70-90% may be maintained by using an organic loading of 3.2-6.3kg COD/m{sup 3} day and 0.6-1.6 kg-COD/m{sup 3} day with an HRT of 6.0 h as secondary and advanced treatment system, respectively. The time required for the BAC bed to be regenerated by a thermal regeneration is prolonged 4-5 times more than that of GAC system. It can be estimated that the enhanced COD removal capability of the biofilm was not only due to the increase in the COD removal capability of acclimated bacteria, but also due to species succession of bacteria in bio-film ecosystem. (Author)

  8. Human COQ9 Rescues a coq9 Yeast Mutant by Enhancing Coenzyme Q Biosynthesis from 4-Hydroxybenzoic Acid and Stabilizing the CoQ-Synthome

    Directory of Open Access Journals (Sweden)

    Cuiwen H. He

    2017-07-01

    Full Text Available Coq9 is required for the stability of a mitochondrial multi-subunit complex, termed the CoQ-synthome, and the deamination step of Q intermediates that derive from para-aminobenzoic acid (pABA in yeast. In human, mutations in the COQ9 gene cause neonatal-onset primary Q10 deficiency. In this study, we determined whether expression of human COQ9 could complement yeast coq9 point or null mutants. We found that expression of human COQ9 rescues the growth of the temperature-sensitive yeast mutant, coq9-ts19, on a non-fermentable carbon source and increases the content of Q6, by enhancing Q biosynthesis from 4-hydroxybenzoic acid (4HB. To study the mechanism for the rescue by human COQ9, we determined the steady-state levels of yeast Coq polypeptides in the mitochondria of the temperature-sensitive yeast coq9 mutant expressing human COQ9. We show that the expression of human COQ9 significantly increased steady-state levels of yeast Coq4, Coq6, Coq7, and Coq9 at permissive temperature. Human COQ9 polypeptide levels persisted at non-permissive temperature. A small amount of the human COQ9 co-purified with tagged Coq6, Coq6-CNAP, indicating that human COQ9 interacts with the yeast Q-biosynthetic complex. These findings suggest that human COQ9 rescues the yeast coq9 temperature-sensitive mutant by stabilizing the CoQ-synthome and increasing Q biosynthesis from 4HB. This finding provides a powerful approach to studying the function of human COQ9 using yeast as a model.

  9. Indium tin oxide with zwitterionic interfacial design for biosensing applications in complex matrices

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, Nadia T.; Alias, Yatimah; Khor, Sook Mei, E-mail: naomikhor@um.edu.my

    2015-01-15

    Graphical abstract: - Highlights: • The incorporation of a linker and antifouling molecules is an important interfacial design for both affinity and enzymatic biosensors. • The resistance to non-specific protein adsorptions of BSA–FITC and RBITC–Cyt c were determined by confocal laser scanning microscopy. • The antifouling interface allows detection of target analytes in highly complicated biological matrices. - Abstract: Biosensing interfaces consisting of linker molecules (COOH or NH{sub 2}) and charged, antifouling moieties ((-SO{sup 3−} and N{sup +}(Me){sub 3}) for biosensing applications were prepared for the first time by the in situ deposition of mixtures of aryl diazonium cations on indium tin oxide (ITO) electrodes. A linker molecule is required for the attachment of biorecognition molecules (e.g., antibodies, enzymes, DNA chains, and aptamers) close to the transducer surface. The attached molecules improve the biosensing sensitivity and also provide a short response time for analyte detection. Thus, the incorporation of a linker and antifouling molecules is an important interfacial design for both affinity and enzymatic biosensors. The reductive adsorption behavior and electrochemical measurement were studied for (1) an individual compound and (2) a mixture of antifouling zwitterionic molecules together with linker molecules [combination 1: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 1,4-phenylenediamine (PPD); combination 2: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 4-aminobenzoic acid (PABA)] of aryl diazonium cations grafted onto an ITO electrode. The mixture ratios of SP:TMAP:PPD and SP:TMAP:PABA that provided the greatest resistance to non-specific protein adsorptions of bovine serum albumin labeled with fluorescein isothiocyanate (BSA–FITC) and cytochrome c labeled with rhodamine B isothiocyanate (RBITC–Cyt c) were determined by confocal laser scanning microscopy (CLSM). For the surface antifouling study

  10. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

    Directory of Open Access Journals (Sweden)

    Palash Sanphui

    2014-03-01

    Full Text Available Acemetacin (ACM is a non-steroidal anti-inflammatory drug (NSAID, which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM, isonicotinamide (INA, and picolinamide (PAM], caprolactam (CPR, p-aminobenzoic acid (PABA, and piperazine (PPZ. The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable

  11. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.

    Science.gov (United States)

    Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

    2014-03-01

    Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N-H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior

  12. Advances in analytical methods and occurrence of organic UV-filters in the environment — A review

    International Nuclear Information System (INIS)

    Ramos, Sara; Homem, Vera; Alves, Arminda; Santos, Lúcia

    2015-01-01

    UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3 mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

  13. High resolution and high sensitivity methods for oligosaccharide mapping and characterization by normal phase high performance liquid chromatography following derivatization with highly fluorescent anthranilic acid.

    Science.gov (United States)

    Anumula, K R; Dhume, S T

    1998-07-01

    Facile labeling of oligosaccharides (acidic and neutral) in a nonselective manner was achieved with highly fluorescent anthranilic acid (AA, 2-aminobenzoic acid) (more than twice the intensity of 2-aminobenzamide, AB) for specific detection at very high sensitivity. Quantitative labeling in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC for 60 min resulted in negligible or no desialylation of the oligosaccharides. A high resolution high performance liquid chromatographic method was developed for quantitative oligosaccharide mapping on a polymeric-NH2bonded (Astec) column operating under normal phase and anion exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the map by simple evaporation, the chromatographic conditions developed use volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems. The mapping and characterization technology was developed using well characterized standard glycoproteins. The fluorescent oligosaccharide maps were similar to the maps obtained by the high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), except that the fluorescent maps contained more defined peaks. In the map, the oligosaccharides separated into groups based on charge, size, linkage, and overall structure in a manner similar to HPAEC-PAD with contribution of -COOH function from the label, anthranilic acid. However, selectivity of the column for sialic acid linkages was different. A second dimension normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK Gel amide-80) for separation of the AA labeled neutral complex type and isomeric structures of high mannose type oligosaccharides. The oligosaccharides labeled with AA are compatible with biochemical and biophysical techniques, and use of matrix assisted laser desorption mass spectrometry for rapid determination of oligosaccharide mass map of glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC methods

  14. Optimization, biological evaluation and microPET imaging of copper-64-labeled bombesin agonists, [64Cu-NO2A-(X)-BBN(7-14)NH2], in a prostate tumor xenografted mouse model

    International Nuclear Information System (INIS)

    Lane, Stephanie R.; Nanda, Prasanta; Rold, Tammy L.; Sieckman, Gary L.; Figueroa, Said D.; Hoffman, Timothy J.; Jurisson, Silvia S.; Smith, Charles J.

    2010-01-01

    Gastrin-releasing peptide receptors (GRPr) are a member of the bombesin (BBN) receptor family. GRPr are expressed in high numbers on specific human cancers, including human prostate cancer. Therefore, copper-64 ( 64 Cu) radiolabeled BBN(7-14)NH 2 conjugates could have potential for diagnosis of human prostate cancer via positron-emission tomography (PET). The aim of this study was to produce [ 64 Cu-NO2A-(X)-BBN(7-14)NH 2 ] conjugates for prostate cancer imaging, where X=pharmacokinetic modifier (beta-alanine, 5-aminovaleric acid, 6-aminohexanoic acid, 8-aminooctanoic acid, 9-aminonanoic acid or para-aminobenzoic acid) and NO2A=1,4,7-triazacyclononane-1,4-diacetic acid [a derivative of NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid)]. Methods: [(X)-BBN(7-14)NH 2 ] Conjugates were synthesized by solid-phase peptide synthesis (SPPS), after which NOTA was added via manual conjugation. The new peptide conjugates were radiolabeled with 64 Cu radionuclide. The receptor-binding affinity was determined in human prostate PC-3 cells, and tumor-targeting efficacy was determined in PC-3 tumor-bearing severely combined immunodeficient (SCID) mice. Whole-body maximum intensity microPET/CT images of PC-3 tumor-bearing SCID mice were obtained 18 h postinjection (pi). Results: Competitive binding assays in PC-3 cells indicated high receptor-binding affinity for the [NO2A-(X)-BBN(7-14)NH 2 ] and [ nat Cu-NO2A-(X)-BBN(7-14)NH 2 ] conjugates. In vivo biodistribution studies of the [ 64 Cu-NO2A-(X)-BBN(7-14)NH 2 ] conjugates at 1, 4 and 24 h pi showed very high uptake of the tracer in GRPr-positive tissue with little accumulation and retention in nontarget tissues. High-quality, high-contrast microPET images were obtained, with xenografted tumors being clearly visible at 18 h pi. Conclusions: NO2A chelator sufficiently stabilizes copper(II) radiometal under in vivo conditions, producing conjugates with very high uptake and retention in targeted GRPr. Preclinical evaluation of these

  15. Effects of in vivo exposure to UV filters (4-MBC, OMC, BP-3, 4-HB, OC, OD-PABA) on endocrine signaling genes in the insect Chironomus riparius.

    Science.gov (United States)

    Ozáez, Irene; Martínez-Guitarte, José Luis; Morcillo, Gloria

    2013-07-01

    There is increasing evidence indicating that several UV filters might have endocrine disruptive effects. Numerous studies have evaluated hormonal effects in vertebrates, mainly reporting estrogenic and androgenic activities in mammals and fishes. There is only limited knowledge about potential endocrine activity in invertebrate hormonal systems. In this work, the effects on endocrine signaling genes of six frequently used UV filters were investigated in Chironomus riparius, a reference organism in aquatic toxicology. The UV filters studied were: octyl-p-methoxycinnamate (OMC) also called 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4-MBC); benzophenone-3 (BP-3); 4-hidroxybenzophenone (4-HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). After in vivo exposure at different dosages, expression levels of the genes coding for the ecdysone receptor (EcR), the ultraspiracle (usp, ortholog of the RXR) and the estrogen-related receptor (ERR) were quantified by Real Time PCR. The EcR gene was significantly upregulated by 4-MBC, OMC/EHMC and OD-PABA, with a dose-related response following 24h exposure. In contrast, the benzophenones, BP-3 and 4-HB, as well as OC did not alter this gene at the same exposure conditions. The transcription profiles of the usp and ERR genes were not significantly affected, except for BP-3 that inhibited the usp gene at the highest concentration. To our knowledge, this is the first experimental evidence in invertebrates of a direct effect of UV filters on endocrine-related genes, and is consistent with the known effects on vertebrate hormonal receptor genes. The capability of 4-MBC, OMC/EHMC and OD-PABA to stimulate the expression of the ecdysone receptor, a key transcription factor for the ecdysone-genomic response in arthropods, suggests the possibility of a broad and long-term effect on this hormonal pathway. These findings strengthen the need for further research about the ecotoxicological implications

  16. Rapid screening method to study the reactivity of UV filter substances towards skin proteins by high-performance thin-layer chromatography.

    Science.gov (United States)

    Stiefel, C; Schwack, W

    2013-12-01

    Most UV filters used in sunscreens and other cosmetic products contain carbonyl groups, which generally are able to react with peptides or free amino acids of the human skin. To estimate their reactivity, we studied different prominent UV filter substances, octocrylene, ethylhexyl salicylate, 4-t-butyl-4'-methoxydibenzoylmethane, ethylhexyl methoxycinnamate, benzophenone-3, hydroxymethylbenzoyl sulphonic acid, octyldimethyl p-aminobenzoic acid, 3-benzylidene camphor, 4-methylbenzylidene camphor, diethylhexyl butamido triazone and ethylhexyl triazone. A simple screening method using an amino HPTLC plate as protein model was established. The influence of different reaction conditions like heating and irradiation was determined. The ketones BP-3, HMBS and BM-DBM revealed the highest binding rates after both irradiation and heating. After 1 h of irradiation, 82%, 28% and 96%, respectively, were bonded to the amino phase, while heating resulted in values of 52%, 36% and 16%. For BP-3 and HMBS, even storage in the dark at room temperature resulted in a low binding. Contrarily, for the two camphor derivatives 3-BC and 4-MBC, only irradiation led to a slightly turnover. UV filters with ester groups also showed a different behaviour depending on their main skeleton. While OCR especially reacted under heating with the amino phase, resulting in 36% of bound species after one hour, UV irradiation particularly encouraged a reaction of the other esters. After 1 h irradiation, 15% of EHMC, 38% of EHS and 48% of OD-PABA were bonded to the amino groups of the HPTLC plate, whereas the reactivity of the two triazones, EHT and DEBT, was comparatively low. Especially the UV filters BP-3, BM-DBM, HMBS, EHMC or OCR, which are commonly known to cause contact dermatitis, showed a high tendency to form adducts with the amino layer. Thus, the amino plate seems to be a proper tool to screen for skin sensitizers. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  17. Synthesis and oxidation of CpIrIII compounds: functionalization of a Cp methyl group.

    Science.gov (United States)

    Park-Gehrke, Lisa S; Freudenthal, John; Kaminsky, Werner; Dipasquale, Antonio G; Mayer, James M

    2009-03-21

    [CpIrCl(2)](2) () and new CpIr(III)(L-L)X complexes (L-L = N-O or C-N chelating ligands; X = Cl, I, Me) have been prepared and their reactivity with two-electron chemical oxidants explored. Reaction of with PhI(OAc)(2) in wet solvents yields a new chloro-bridged dimer in which each of the Cp ligands has been singly acetoxylated to form [Cp(OAc)Ir(III)Cl(2)](2) () (Cp(OAc) = eta(5)-C(5)Me(4)CH(2)OAc). Complex and related carboxy- and alkoxy-functionalized Cp(OR) complexes can also be prepared from plus (PhIO)(n) and ROH. [Cp(OAc)Ir(III)Cl(2)](2) () and the methoxy analogue [Cp(OMe)Ir(III)Cl(2)](2) () have been structurally characterized. Treatment of [CpIrCl(2)](2) () with 2-phenylpyridine yields CpIr(III)(ppy)Cl () (ppy = cyclometallated 2-phenylpyridyl) which is readily converted to its iodide and methyl analogues CpIr(III)(ppy)I and CpIr(III)(ppy)Me (). CpIr(III) complexes were also prepared with N-O chelating ligands derived from anthranilic acid (2-aminobenzoic acid) and alpha-aminoisobutyric acid (H(2)NCMe(2)COOH), ligands chosen to be relatively oxidation resistant. These complexes and were reacted with potential two-electron oxidants including PhI(OAc)(2), hexachlorocyclohexadienone (C(6)Cl(6)O), N-fluoro-2,4,6-trimethylpyridinium (Me(3)pyF(+)), [Me(3)O]BF(4) and MeOTf (OTf = triflate, CF(3)SO(3)). Iridium(V) complexes were not observed or implicated in these reactions, despite the similarity of the potential products to known CpIr(V) species. The carbon electrophiles [Me(3)O]BF(4) and MeOTf appear to react preferentially at the N-O ligands, to give methyl esters in some cases. Overall, the results indicate that Cp is not inert under oxidizing conditions and is therefore not a good supporting ligand for oxidizing organometallic complexes.

  18. Porcine dentin sialoprotein glycosylation and glycosaminoglycan attachments.

    Science.gov (United States)

    Yamakoshi, Yasuo; Nagano, Takatoshi; Hu, Jan Cc; Yamakoshi, Fumiko; Simmer, James P

    2011-02-03

    Dentin sialophosphoprotein (Dspp) is a multidomain, secreted protein that is critical for the formation of tooth dentin. Mutations in DSPP cause inherited dentin defects categorized as dentin dysplasia type II and dentinogenesis imperfecta type II and type III. Dentin sialoprotein (Dsp), the N-terminal domain of dentin sialophosphoprotein (Dspp), is a highly glycosylated proteoglycan, but little is known about the number, character, and attachment sites of its carbohydrate moieties. To identify its carbohydrate attachment sites we isolated Dsp from developing porcine molars and digested it with endoproteinase Glu-C or pronase, fractionated the digestion products, identified fractions containing glycosylated peptides using a phenol sulfuric acid assay, and characterized the glycopeptides by N-terminal sequencing, amino acid analyses, or LC/MSMS. To determine the average number of sialic acid attachments per N-glycosylation, we digested Dsp with glycopeptidase A, labeled the released N-glycosylations with 2-aminobenzoic acid, and quantified the moles of released glycosylations by comparison to labeled standards of known concentration. Sialic acid was released by sialidase digestion and quantified by measuring β-NADH reduction of pyruvic acid, which was generated stoichiometrically from sialic acid by aldolase. To determine its forms, sialic acid released by sialidase digestion was labeled with 1,2-diamino-4,5-methyleneoxybenzene (DMB) and compared to a DMB-labeled sialic acid reference panel by RP-HPLC. To determine the composition of Dsp glycosaminoglycan (GAG) attachments, we digested Dsp with chondroitinase ABC and compared the chromotagraphic profiles of the released disaccharides to commercial standards. N-glycosylations were identified at Asn37, Asn77, Asn136, Asn155, Asn161, and Asn176. Dsp averages one sialic acid per N-glycosylation, which is always in the form of N-acetylneuraminic acid. O-glycosylations were tentatively assigned at Thr200, Thr216 and Thr

  19. Porcine dentin sialoprotein glycosylation and glycosaminoglycan attachments

    Directory of Open Access Journals (Sweden)

    Yamakoshi Fumiko

    2011-02-01

    Full Text Available Abstract Background Dentin sialophosphoprotein (Dspp is a multidomain, secreted protein that is critical for the formation of tooth dentin. Mutations in DSPP cause inherited dentin defects categorized as dentin dysplasia type II and dentinogenesis imperfecta type II and type III. Dentin sialoprotein (Dsp, the N-terminal domain of dentin sialophosphoprotein (Dspp, is a highly glycosylated proteoglycan, but little is known about the number, character, and attachment sites of its carbohydrate moieties. Results To identify its carbohydrate attachment sites we isolated Dsp from developing porcine molars and digested it with endoproteinase Glu-C or pronase, fractionated the digestion products, identified fractions containing glycosylated peptides using a phenol sulfuric acid assay, and characterized the glycopeptides by N-terminal sequencing, amino acid analyses, or LC/MSMS. To determine the average number of sialic acid attachments per N-glycosylation, we digested Dsp with glycopeptidase A, labeled the released N-glycosylations with 2-aminobenzoic acid, and quantified the moles of released glycosylations by comparison to labeled standards of known concentration. Sialic acid was released by sialidase digestion and quantified by measuring β-NADH reduction of pyruvic acid, which was generated stoichiometrically from sialic acid by aldolase. To determine its forms, sialic acid released by sialidase digestion was labeled with 1,2-diamino-4,5-methyleneoxybenzene (DMB and compared to a DMB-labeled sialic acid reference panel by RP-HPLC. To determine the composition of Dsp glycosaminoglycan (GAG attachments, we digested Dsp with chondroitinase ABC and compared the chromotagraphic profiles of the released disaccharides to commercial standards. N-glycosylations were identified at Asn37, Asn77, Asn136, Asn155, Asn161, and Asn176. Dsp averages one sialic acid per N-glycosylation, which is always in the form of N-acetylneuraminic acid. O-glycosylations were

  20. Human Plasma N-glycosylation as Analyzed by Matrix-Assisted Laser Desorption/Ionization-Fourier Transform Ion Cyclotron Resonance-MS Associates with Markers of Inflammation and Metabolic Health*

    Science.gov (United States)

    Reiding, Karli R.; Ruhaak, L. Renee; Uh, Hae-Won; el Bouhaddani, Said; van den Akker, Erik B.; Plomp, Rosina; McDonnell, Liam A.; Houwing-Duistermaat, Jeanine J.; Slagboom, P. Eline; Beekman, Marian; Wuhrer, Manfred

    2017-01-01

    Glycosylation is an abundant co- and post-translational protein modification of importance to protein processing and activity. Although not template-defined, glycosylation does reflect the biological state of an organism and is a high-potential biomarker for disease and patient stratification. However, to interpret a complex but informative sample like the total plasma N-glycome, it is important to establish its baseline association with plasma protein levels and systemic processes. Thus far, large-scale studies (n >200) of the total plasma N-glycome have been performed with methods of chromatographic and electrophoretic separation, which, although being informative, are limited in resolving the structural complexity of plasma N-glycans. MS has the opportunity to contribute additional information on, among others, antennarity, sialylation, and the identity of high-mannose type species. Here, we have used matrix-assisted laser desorption/ionization (MALDI)-Fourier transform ion cyclotron resonance (FTICR)-MS to study the total plasma N-glycome of 2144 healthy middle-aged individuals from the Leiden Longevity Study, to allow association analysis with markers of metabolic health and inflammation. To achieve this, N-glycans were enzymatically released from their protein backbones, labeled at the reducing end with 2-aminobenzoic acid, and following purification analyzed by negative ion mode intermediate pressure MALDI-FTICR-MS. In doing so, we achieved the relative quantification of 61 glycan compositions, ranging from Hex4HexNAc2 to Hex7HexNAc6dHex1Neu5Ac4, as well as that of 39 glycosylation traits derived thereof. Next to confirming known associations of glycosylation with age and sex by MALDI-FTICR-MS, we report novel associations with C-reactive protein (CRP), interleukin 6 (IL-6), body mass index (BMI), leptin, adiponectin, HDL cholesterol, triglycerides (TG), insulin, gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), and smoking. Overall, the

  1. Tautomeric and Microscopic Protonation Equilibria of Anthranilic Acid and Its Derivatives.

    Science.gov (United States)

    Zapała, Lidia; Woźnicka, Elżbieta; Kalembkiewicz, Jan

    2014-01-01

    The acid-base chemistry of three zwitterionic compounds, namely anthranilic (2-aminobenzoic acid), N -methylanthranilic and N -phenylanthranilic acid has been characterized in terms of the macroconstants K a1 , K a2 , the isoelectric point p H I , the tautomerization constant K z and microconstants k 11 , k 12 , k 21 , k 22 . The potentiometric titration method was used to determine the macrodissociation constants. Due to the very poor water solubility of N -phenylanthranilic acid the dissociation constants p K a1 and p K a2 were determined in MDM-water mixtures [MDM is a co-solvent mixture, consisting of equal volumes of methanol (MeOH), dioxane and acetonitrile (MeCN)]. The Yasuda-Shedlovsky extrapolation procedure has been used to obtain the values of p K a1 and p K a2 in aqueous solutions. The p K a1 and p K a2 values obtained by this method are 2.86 ± 0.01 and 4.69 ± 0.03, respectively. The tautomerization constant K z describing the equilibrium between unionized form ⇌ zwitterionic form was evaluated by the K z method based on UV-VIS spectrometry. The method uses spectral differences between the zwitterionic form (found at isoelectric pH in aqueous solution) and the unionized form (formed in an organic solvent of low dielectric constant). The highest value of the K z constant has been observed in the case of N -methylantranilic acid (log 10 K z  = 1.31 ± 0.04). The values of log 10 K z for anthranilic and N -phenylanthranilic acids are similar and have values of 0.93 ± 0.03 and 0.90 ± 0.05, respectively. The results indicate that the tested compounds, in aqueous solution around the isoelectric point pH I , occur mainly in the zwitterionic form. Moreover, the influence of the type of substituent and pH of the aqueous phase on the equilibrium were analyzed with regard to the formation and the coexistence of different forms of the acids in the examined systems.

  2. Microscale Measurements of Michaelis–Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage

    Science.gov (United States)

    2016-01-01

    Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis–Menten constants (KM) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A KM value of 3.3 ± 0.8 mM (Vmax, 2100 ± 200 μM/min) was obtained for 3′-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a KM of 2 ± 1 mM (Vmax, 400 ± 100 μM/min) was obtained for the 6′-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a KM value of 3 ± 2 mM (Vmax, 900 ± 300 μM/min) for 3′-sialyllactose. With a knowledge of Vmax, the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3′ and 6′ sialic acid linkages. PMID:27936604

  3. Quantitative glycan profiling of normal human plasma derived immunoglobulin and its fragments Fab and Fc.

    Science.gov (United States)

    Anumula, Kalyan Rao

    2012-08-31

    Typical clinical grade human IgG (intravenous immunoglobulin, IVIG), used for carbohydrate analysis, is derived from thousands of healthy donors. Quantitative high-resolution glycan profiles of IgG and its Fc-Fab fragments are presented here. Glycan profiles were established following digestions with Fc specific endoglycosidase S and generic PNGase F under denaturing and non-denaturing (native) conditions. The native PNGase F glycan profile of IgG was similar (but not identical) to that of Endo S. Endo S profiles did not contain the glycans with bisecting GlcNAc. PNGase F glycan profiles were the same for Fc fragments that were isolated from pepsin and Ide S protease digests. Both isolated Fab fragments and the previously deglycosylated IVIG (native conditions) yielded the same glycan profile. Glycan profiles were established using high resolution HPLC with 2-aminobenzoic acid (2AA) labeling. An accurate determination of sialylation levels can be made by this method. Carbohydrate content in Fc and Fab was determined using an internal standard and corrected for both protein and glycan recoveries. Fab portion contained about 14% of the total carbohydrate which translates to 2.3 sugar chains per mol in IVIG where 2 chains are located in the CH2 domain of the Fc. Fc glycans consisted of neutral (N) 84.5%; mono-sialylated (S1) 15% and di-sialylated (S2) 0.5%. In contrast, Fab contained N, 21%; S1, 43% and S2, 36%. The distribution of bisecting N-acetylglucosamine and fucose was found to be very different in various glycans (N, S1 and S2) found in Fab and Fc. Total IgG glycan profile (Fab plus Fc) contained N, 78.5%; S1, 17% and S2, 4.5%. Percent distribution of glycans G0, G1 and G2 (with 0, 1 and 2 two galactoses) was 26, 49 and 25 respectively within the 78% of the neutral glycans. Glycan profiles were nearly the same for various clinical grade IVIG preparations from various manufacturers. A fast HPLC profiling method was developed for the separation and quantitation

  4. Microscale Measurements of Michaelis-Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage.

    Science.gov (United States)

    Gattu, Srikanth; Crihfield, Cassandra L; Holland, Lisa A

    2017-01-03

    Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis-Menten constants (K M ) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A K M value of 3.3 ± 0.8 mM (V max , 2100 ± 200 μM/min) was obtained for 3'-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a K M of 2 ± 1 mM (V max , 400 ± 100 μM/min) was obtained for the 6'-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a K M value of 3 ± 2 mM (V max , 900 ± 300 μM/min) for 3'-sialyllactose. With a knowledge of V max , the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3' and 6' sialic acid linkages.

  5. MONITORING KADAR NITRIT DAN NITRAT PADA AIR SUMUR DI DAERAH CATUR TUNGGAL YOGYAKARTA DENGAN METODE SPEKTROFOTOMETRI UV-VIS (Monitoring of Nitrite and Nitrate Content in Ground Water of Catur Tunggal Region of Yogyakarta by UV-VIS Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Setiowati Setiowati

    2016-07-01

    Full Text Available ABSTRAK Metode analisis nitrit dan nitrat perlu dikembangkan untuk memonitor kualitas air minum. Kualitas air sumur untuk parameter nitrit dan nitrat dipengaruhi oleh kondisi lingkungan dan kedalaman air sumur.Penelitian ini bertujuan menganalisis nitrit dan nitrat menggunakan asam p-aminobenzoat (PABA pada air sumur di daerah perkotaan Yogyakarta. Analisis nitrit didasarkan pada reaksi antara ion nitrit dengan PABA yang membentuk senyawa azo dengan panjang gelombang maksimum 546 nm. Kedalaman air sumur di daerah Catur Tunggal rata-rata > 10 m. Kadar nitrit dan nitrat pada air sumur adalah 0,05-0,09 dan 8,22-36,58 mg/L. Kadar nitrit dan nitrat tersebut memenuhi baku mutu dan aman untuk dikonsumsi. Konsentrasi nitrit dan nitrat pada air RO adalah 0,05 dan 2,72-59,57 mg/L. Kadar nitrit pada air RO tidak memenuhi baku mutu sedangkan kadar nitrat memenuhi baku mutu kecuali RO 5. ABSTRACT The method for analysis nitrite and nitrate had to developed to monitor the drinking water quality. The well water quality, especially for nitrite and nitrate were influenced by environmental conditions and depth of well. This study aims to analyze nitrite and nitrate using p-aminobenzoic acid (PABA in ground water at urban areas of Yogyakarta. The analysis was based on the reaction between nitrite ions with PABA which form azo compounds with a maximum wavelength of 546 nm. The depth of wells at Catur Tunggal were more than 10 m. Concentration of nitrite and nitrate in well water were 0.05 to 0.09 and 8.22 to 36.58 mg / L. The concentrations met the standard for drinking water quality and was safe for consumption. The concentration of nitrite and nitrate in reverse osmosis (RO water were 0.05 and 2.72 to 59.57 mg / L. The concentration of nitrite did not meet the standard for drinking water quality while the concentration of nitrate met the standard for drinking water quality except RO 5.

  6. Aggravation of cold-induced injury in Vero-B4 cells by RPMI 1640 medium – Identification of the responsible medium components

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    Pless-Petig Gesine

    2012-10-01

    Full Text Available Abstract Background In modern biotechnology, there is a need for pausing cell lines by cold storage to adapt large-scale cell cultures to the variable demand for their products. We compared various cell culture media/solutions for cold storage of Vero-B4 kidney cells, a cell line widely used in biotechnology. Results Cold storage in RPMI 1640 medium, a recommended cell culture medium for Vero-B4 cells, surprisingly, strongly enhanced cold-induced cell injury in these cells in comparison to cold storage in Krebs-Henseleit buffer or other cell culture media (DMEM, L-15 and M199. Manufacturer, batch, medium supplements and the most likely components with concentrations outside the range of the other media/solutions (vitamin B12, inositol, biotin, p-aminobenzoic acid did not cause this aggravation of cold-induced injury in RPMI 1640. However, a modified Krebs-Henseleit buffer with a low calcium concentration (0.42 mM, a high concentration of inorganic phosphate (5.6 mM, and glucose (11.1 mM; i.e. concentrations as in RPMI 1640 evoked a cell injury and loss of metabolic function corresponding to that observed in RPMI 1640. Deferoxamine improved cell survival and preserved metabolic function in modified Krebs-Henseleit buffer as well as in RPMI 1640. Similar Ca2+ and phosphate concentrations did not increase cold-induced cell injury in the kidney cell line LLC-PK1, porcine aortic endothelial cells or rat hepatocytes. However, more extreme conditions (Ca2+ was nominally absent and phosphate concentration raised to 25 mM as in the organ preservation solution University of Wisconsin solution also increased cold-induced injury in rat hepatocytes and porcine aortic endothelial cells. Conclusion These data suggest that the combination of low calcium and high phosphate concentrations in the presence of glucose enhances cold-induced, iron-dependent injury drastically in Vero-B4 cells, and that a tendency for this pathomechanism also exists in other cell types.

  7. Human Plasma N-glycosylation as Analyzed by Matrix-Assisted Laser Desorption/Ionization-Fourier Transform Ion Cyclotron Resonance-MS Associates with Markers of Inflammation and Metabolic Health.

    Science.gov (United States)

    Reiding, Karli R; Ruhaak, L Renee; Uh, Hae-Won; El Bouhaddani, Said; van den Akker, Erik B; Plomp, Rosina; McDonnell, Liam A; Houwing-Duistermaat, Jeanine J; Slagboom, P Eline; Beekman, Marian; Wuhrer, Manfred

    2017-02-01

    Glycosylation is an abundant co- and post-translational protein modification of importance to protein processing and activity. Although not template-defined, glycosylation does reflect the biological state of an organism and is a high-potential biomarker for disease and patient stratification. However, to interpret a complex but informative sample like the total plasma N-glycome, it is important to establish its baseline association with plasma protein levels and systemic processes. Thus far, large-scale studies (n >200) of the total plasma N-glycome have been performed with methods of chromatographic and electrophoretic separation, which, although being informative, are limited in resolving the structural complexity of plasma N-glycans. MS has the opportunity to contribute additional information on, among others, antennarity, sialylation, and the identity of high-mannose type species.Here, we have used matrix-assisted laser desorption/ionization (MALDI)-Fourier transform ion cyclotron resonance (FTICR)-MS to study the total plasma N-glycome of 2144 healthy middle-aged individuals from the Leiden Longevity Study, to allow association analysis with markers of metabolic health and inflammation. To achieve this, N-glycans were enzymatically released from their protein backbones, labeled at the reducing end with 2-aminobenzoic acid, and following purification analyzed by negative ion mode intermediate pressure MALDI-FTICR-MS. In doing so, we achieved the relative quantification of 61 glycan compositions, ranging from Hex 4 HexNAc 2 to Hex 7 HexNAc 6 dHex 1 Neu5Ac 4 , as well as that of 39 glycosylation traits derived thereof. Next to confirming known associations of glycosylation with age and sex by MALDI-FTICR-MS, we report novel associations with C-reactive protein (CRP), interleukin 6 (IL-6), body mass index (BMI), leptin, adiponectin, HDL cholesterol, triglycerides (TG), insulin, gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), and smoking. Overall

  8. The influence of virus infections on antioxidant levels in the genetically modified plum variety "Honeysweet" (Prunus domestica L.

    Directory of Open Access Journals (Sweden)

    Jiri Sochor

    2015-08-01

    Full Text Available It is well-known that polyphenolic compounds are found abundantly in fruit, but various kinds of diseases  lower these levels. This work measures total polyphenolic content, antioxidant activity and the levels of specific important antioxidants in fruits of the genetically modified (GM plum variety HoneySweet, trees  which were previously inoculated with a range of different virus infections.  These were the Plum Pox virus (PPV, Prune Dwarf virus (PDV and Apple Chlorotic Leaf-Spot virus (ACLSV. Uninoculated trees were used as controls. Antioxidant activity was measured using four different photometric  methods – DPPH (2,2-diphenyl-1-picrylhydrazyl, DMPD (N-dimethyl-p-phenylenediamine, ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and FRAP (Ferric reducing antioxidant power. Total polyphenol content was measured using the Folin–Ciocalteau method. The profiles of 10 specific antioxidant constituents in the fruits of the GM plum variety HoneySweet were detected and analyzed, since these are of interest for their role in human diets and could play a role in the resistance of plants to viruses. Detection was made using HPLC with UV-VIS detection.  They were: gallic acid, p-coumaric acid, 4-aminobenzoic acid, chlorogenic acid, caffeic acid, ferulic acid, vanillin, rutin and quercetin. The compound with the highest concentration was chlorogenic acid (587 mg/100 g, and that with the lowest was p-coumaric acid (0.95 mg/100 g. Of the four methods of antioxidant activity used, in three the lowest levels of antioxidant activity were seen where the PPV virus was combined with ACLSV, and in three the highest levels were seen in the un-inoculated control without any infection. The highest values of total polyphenols were seen in the control (65.3 mg/100 g, followed by infection of PPV, then treatment PPV, PDV and ACLSV, then treatment PPV and PDV and finally the lowest levels were seen in treatment PPV and ACLSV (44.2 mg/100 g, which

  9. Influência do defloculante na deposição de alumina por eletroforese The influence of deflocullant on alumina deposition by electrophoresis

    Directory of Open Access Journals (Sweden)

    M. V. Gelfuso

    2003-12-01

    Full Text Available A conformação de materiais cerâmicos por eletroforese é conhecida por ser de baixo custo e necessitar de pouca infra-estrutura para fabricação de recobrimentos e laminados cerâmicos. O método é simples, mas o principal problema é a toxicidade associada aos solventes orgânicos usualmente utilizados como meio de dispersão. Este trabalho visa obter corpos cerâmicos de alumina através do processo de eletroforese, utilizando barbotinas aquosas. Para determinar a estabilidade das barbotinas, contendo diferentes tipos de defloculantes, medidas qualitativas de viscosidade através do método de Pitot e pH foram realizadas. Estes parâmetros foram acompanhados em suspensões contendo entre 0,5 e 4,0% em massa de defloculantes como poli-acrilato de amônio (DREW, ácido para-amino benzóico (PABA e quitosana. O maior valor de densidade a verde (37,5% da teórica e taxa de deposição (33,2 mg/min foi obtido para corpos cerâmicos depositados a 6,0 V/mm dispersados com DREW.Electrophoresis forming is an economical and reliable method for the fabrication of coatings and laminate ceramics. The process is simple, but a major problem is the toxicity and environmental problem associated with the organic solvents usually employed as vehicle media. This work aims to obtain bodies of Al2O3 by electrophoretic deposition using aqueous slips. The stability of the slips was studied, as a function of the different dispersants, by qualitative measures of viscosity by the Pitot and pH method. These processing parameters were accomplished in suspensions containing between 0.5 to 4.0wt.% of dispersants as the poli(ammonium acrylate (DREW, para-aminobenzoic acid (PABA and quitosan. The largest value of green density, 37.5% of the theoretical density and deposition rate, 33.2 mg/min, was obtained for bodies deposited in 6.0 V/cm with DREW.

  10. Advances in analytical methods and occurrence of organic UV-filters in the environment--A review.

    Science.gov (United States)

    Ramos, Sara; Homem, Vera; Alves, Arminda; Santos, Lúcia

    2015-09-01

    UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

  11. Advances in analytical methods and occurrence of organic UV-filters in the environment — A review

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Sara; Homem, Vera, E-mail: vhomem@fe.up.pt; Alves, Arminda; Santos, Lúcia

    2015-09-01

    UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3 mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

  12. Transcriptional Responses in root and leaf of Prunus persica Under Drought Stress Using RNA Sequencing

    Directory of Open Access Journals (Sweden)

    Najla Ksouri

    2016-11-01

    Full Text Available Prunus persica L. Batch, or peach, is one of the most important crops and it is widely established in irrigated arid and semi-arid regions. However, due to variations in the climate and the increased aridity, drought has become a major constraint, causing crop losses worldwide. The use of drought-tolerant rootstocks in modern fruit production appears to be a useful method of alleviating water deficit problems. However, the transcriptomic variation and the major molecular mechanisms that underlie the adaptation of drought-tolerant rootstocks to water shortage remain unclear. Hence, in this study, high-throughput sequencing (RNA-seq was performed to assess the transcriptomic changes and the key genes involved in the response to drought in root tissues (GF677 rootstock and leaf tissues (graft, var. Catherina subjected to 16 days of drought stress. In total, 12 RNA libraries were constructed and sequenced. This generated a total of 315M raw reads from both tissues, which allowed the assembly of 22,079 and 17,854 genes associated with the root and leaf tissues, respectively. Subsets of 500 differentially expressed genes (DEGs in roots and 236 in leaves were identified and functionally annotated with 56 gene ontology (GO terms and 99 metabolic pathways, which were mostly associated with aminobenzoate degradation and phenylpropanoid biosynthesis. The GO analysis highlighted the biological functions that were exclusive to the root tissue, such as locomotion, hormone metabolic process, and detection of stimulus, indicating the stress-buffering role of the GF677 rootstock. Furthermore, the complex regulatory network involved in the drought response was revealed, involving proteins that are associated with signaling transduction, transcription and hormone regulation, redox homeostasis, and frontline barriers. We identified two poorly characterized genes in P. persica: growth-regulating factor 5 (GRF5, which may be involved in cellular expansion, and AtHB12

  13. Indium tin oxide with zwitterionic interfacial design for biosensing applications in complex matrices

    International Nuclear Information System (INIS)

    Darwish, Nadia T.; Alias, Yatimah; Khor, Sook Mei

    2015-01-01

    Graphical abstract: - Highlights: • The incorporation of a linker and antifouling molecules is an important interfacial design for both affinity and enzymatic biosensors. • The resistance to non-specific protein adsorptions of BSA–FITC and RBITC–Cyt c were determined by confocal laser scanning microscopy. • The antifouling interface allows detection of target analytes in highly complicated biological matrices. - Abstract: Biosensing interfaces consisting of linker molecules (COOH or NH 2 ) and charged, antifouling moieties ((-SO 3− and N + (Me) 3 ) for biosensing applications were prepared for the first time by the in situ deposition of mixtures of aryl diazonium cations on indium tin oxide (ITO) electrodes. A linker molecule is required for the attachment of biorecognition molecules (e.g., antibodies, enzymes, DNA chains, and aptamers) close to the transducer surface. The attached molecules improve the biosensing sensitivity and also provide a short response time for analyte detection. Thus, the incorporation of a linker and antifouling molecules is an important interfacial design for both affinity and enzymatic biosensors. The reductive adsorption behavior and electrochemical measurement were studied for (1) an individual compound and (2) a mixture of antifouling zwitterionic molecules together with linker molecules [combination 1: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 1,4-phenylenediamine (PPD); combination 2: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 4-aminobenzoic acid (PABA)] of aryl diazonium cations grafted onto an ITO electrode. The mixture ratios of SP:TMAP:PPD and SP:TMAP:PABA that provided the greatest resistance to non-specific protein adsorptions of bovine serum albumin labeled with fluorescein isothiocyanate (BSA–FITC) and cytochrome c labeled with rhodamine B isothiocyanate (RBITC–Cyt c) were determined by confocal laser scanning microscopy (CLSM). For the surface antifouling study, we used 2

  14. Indium tin oxide with zwitterionic interfacial design for biosensing applications in complex matrices

    Science.gov (United States)

    Darwish, Nadia T.; Alias, Yatimah; Khor, Sook Mei

    2015-01-01

    Biosensing interfaces consisting of linker molecules (COOH or NH2) and charged, antifouling moieties ((sbnd SO3- and N+(Me)3) for biosensing applications were prepared for the first time by the in situ deposition of mixtures of aryl diazonium cations on indium tin oxide (ITO) electrodes. A linker molecule is required for the attachment of biorecognition molecules (e.g., antibodies, enzymes, DNA chains, and aptamers) close to the transducer surface. The attached molecules improve the biosensing sensitivity and also provide a short response time for analyte detection. Thus, the incorporation of a linker and antifouling molecules is an important interfacial design for both affinity and enzymatic biosensors. The reductive adsorption behavior and electrochemical measurement were studied for (1) an individual compound and (2) a mixture of antifouling zwitterionic molecules together with linker molecules [combination 1: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 1,4-phenylenediamine (PPD); combination 2: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 4-aminobenzoic acid (PABA)] of aryl diazonium cations grafted onto an ITO electrode. The mixture ratios of SP:TMAP:PPD and SP:TMAP:PABA that provided the greatest resistance to non-specific protein adsorptions of bovine serum albumin labeled with fluorescein isothiocyanate (BSA-FITC) and cytochrome c labeled with rhodamine B isothiocyanate (RBITC-Cyt c) were determined by confocal laser scanning microscopy (CLSM). For the surface antifouling study, we used 2-[2-(2-methoxyethoxy) ethoxy]acetic acid (OEG) as a standard control because of its prominent antifouling properties. Surface compositions of combinations 1 and 2 were characterized using X-ray photoelectron spectroscopy (XPS). Field-emission scanning electron microscopy (FE-SEM) was used to characterize the morphology of the grafted films to confirm the even distribution between linker and antifouling molecules grafted onto the ITO surfaces

  15. PA-1, a Versatile Anaerobe Obtained in Pure Culture, Catabolizes Benzenoids and Other Compounds in Syntrophy with Hydrogenotrophs, and P-2 plus Wolinella sp. Degrades Benzenoids

    Science.gov (United States)

    Barik, Sudhakar; Brulla, W. J.; Bryant, M. P.

    1985-01-01

    Methanogenic enrichments catabolizing 13 mM phenylacetate or 4 mM phenol were established at 37°C, using a 10% inoculum from a municipal anaerobic digester. By using agar roll tubes of the basal medium plus 0.1% yeast extract-25 mM fumarate, a hydrogenotrophic lawn of Wolinella succinogenes and phenol or phenylacetate, strains P-2 and PA-1, respectively, were isolated in coculture with W. succinogenes. With the lawn deleted, PA-1 was isolated in pure culture. Strain P-2 is apparently a new species of anaerobic, motile, gram-negative, spindle-shaped, small rod that as yet has been grown only in coculture with W. succinogenes. It used phenol, hydrocinnamate, benzoate, and phenylacetate as energy sources. Product recovery by the coculture, per mole of phenol and 4.4 mol of fumarate used, included 2.03, 0.12, 0.08, and 3.23 mol, respectively, of acetate, propionate, butyrate, and succinate. Carbon recovery was 75% and H recovery was 80%, although CO2 and a few other possible products were not determined. That P-2 is an obligate proton-reducing acetogen and possible pathways for its degradation of phenol are discussed. Strain PA-1 is apparently a new species of anaerobic, motile, relatively small, gram-negative rod. It utilized compounds such as phenylacetate, hydrocinnamate, benzoate, phenol, resorcinol, gallate, 4-aminophenol, 2-aminobenzoate, pyruvate, Casamino Acids, and aspartate as energy sources in coculture with W. succinogenes. Per mole of phenylacetate and 1.44 mol of fumarate used, 1.04, 0.53, and 0.78 mol of acetate, propionate, and succinate, respectively, were recovered from the coculture. Only about 50% of the carbon and H were recovered. In coculture with Methanospirillum hungatei, 0.96 mol of acetate and 0.25 mol of methane were recovered per mol of pyruvate used; 0.90 mol of acetate and 0.33 mol of methane, per mol of fumarate used; 0.93 mol of acetate and 0.54 mol of methane, per mol of aspartate used; and 1.71 mol of acetate and 0.57 mol of methane

  16. Morphological and physical characterization of poly(styrene-isobutylene-styrene) block copolymers and ionomers thereof

    Science.gov (United States)

    Baugh, Daniel Webster, III

    of a third phase attributed to PIB chains near the PS domain interface which experience reduced mobility due to their firm attachment to the hard PS domain. The relative amount of this phase decreased in samples with larger PS blocks, while the temperature of the associated transition increased. Tensile testing showed increased tensile strength but decreased elongation at break with larger PS blocks. DMA of the ionomers indicated improved dynamic modulus at temperatures above 100spcirc$C. Tensile testing of the ionomers indicated slight improvements in tensile strength with little loss in elongation at break. PS-PIB-PS block copolymer ionomer (BCP01, center block molecular weight = 53,000 g/mole; 25.5 wt % polystyrene, 4.7% sulfonation of phenyl units, 100% neutralized with KOH) was compounded with various organic and inorganic acid salts of 2-ethylhexyl-p-dimethyl aminobenzoate (ODAB) to explore the efficacy of these compounds as ionic plasticizers. (Abstract shortened by UMI.)

  17. The use of Fluorescence Resonance Energy Transfer (FRET peptidesfor measurement of clinically important proteolytic enzymes

    Directory of Open Access Journals (Sweden)

    Adriana K. Carmona

    2009-09-01

    Full Text Available Proteolytic enzymes have a fundamental role in many biological processes and are associated with multiple pathological conditions. Therefore, targeting these enzymes may be important for a better understanding of their function and development of therapeutic inhibitors. Fluorescence Resonance Energy Transfer (FRET peptides are convenient tools for the study of peptidases specificity as they allow monitoring of the reaction on a continuous basis, providing a rapid method for the determination of enzymatic activity. Hydrolysis of a peptide bond between the donor/acceptor pair generates fluorescence that permits the measurement of the activity of nanomolar concentrations of the enzyme. The assays can be performed directly in a cuvette of the fluorimeter or adapted for determinations in a 96-well fluorescence plate reader. The synthesis of FRET peptides containing ortho-aminobenzoic acid (Abz as fluorescent group and 2, 4-dinitrophenyl (Dnp or N-(2, 4-dinitrophenylethylenediamine (EDDnp as quencher was optimized by our group and became an important line of research at the Department of Biophysics of the Federal University of São Paulo. Recently, Abz/Dnp FRET peptide libraries were developed allowing high-throughput screening of peptidases substrate specificity. This review presents the consolidation of our research activities undertaken between 1993 and 2008 on the synthesis of peptides and study of peptidases specificities.As enzimas proteolíticas têm um papel fundamental em muitos processos biológicos e estão associadas a vários estados patológicos. Por isso, o estudo da especificidade das peptidases pode ser importante para uma melhor compreensão da função destas enzimas e para o desenvolvimento de inibidores. Os substratos com supressão intramolecular de fluorescência constituem uma excelente ferramenta, pois permitem o monitoramento da reação de forma contínua, proporcionando um método prático e rápido para a determinação da

  18. Cupric ion reducing antioxidant capacity assay for antioxidants in human serum and for hydroxyl radical scavengers.

    Science.gov (United States)

    Apak, Reşat; Güçlü, Kubilay; Ozyürek, Mustafa; Bektaşoğlu, Burcu; Bener, Mustafa

    2010-01-01

    , for which the FRAP (ferric reducing antioxidant potency) test is basically nonresponsive. The additivity of absorbances of all the tested antioxidants confirmed that antioxidants in the CUPRAC test do not chemically interact among each other so as to cause an intensification or quenching of the theoretically expected absorbance, and that a total antioxidant capacity (TAC) assay of serum is possible. As a distinct advantage over other electron-transfer based assays (e.g., Folin, FRAP, ABTS, DPPH), CUPRAC is superior in regard to its realistic pH close to the physiological pH, favorable redox potential, accessibility and stability of reagents, and applicability to lipophilic antioxidants as well as hydrophilic ones. The CUPRAC procedure can also assay hydroxyl radicals, being the most reactive oxygen species (ROS). As a more convenient, efficient, and less costly alternative to HPLC/electrochemical detection techniques and to the nonspecific, low-yield TBARS test, we use p-aminobenzoate, 2,4- and 3,5-dimethoxybenzoate probes for detecting hydroxyl radicals generated from an equivalent mixture of [Fe(II)+EDTA] with hydrogen peroxide. The produced hydroxyl radicals attack both the probe and the water-soluble antioxidants in 37 degrees C-incubated solutions for 2 h. The CUPRAC absorbance of the ethylacetate extract due to the reduction of Cu(II)-neocuproine reagent by the hydroxylated probe decreases in the presence of (.)OH scavengers, the difference being proportional to the scavenging ability of the tested compound. The developed method is less lengthy, more specific, and of a higher yield than the classical TBARS assay.