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Sample records for 8-yi methyl carbamic

  1. DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PESTICIDES

    The US EPAs N-Methyl Carbamate Cumulative Risk Assessment (NMCRA) assesses the effect on acetylcholine esterase (AChE) activity of exposure to 10 N-methyl carbamate (NMC) pesticides through dietary, drinking water, and residential exposures.

  2. Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions

    Jun Jie Gao; Hui Quan Li; Yi Zhang

    2007-01-01

    Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.

  3. The dissociation chemistry of ionized methyl carbamate and its isomers revisited: Theory and experiment in concert

    P.C. Burgers (Peter); G.A. McGibbon (Graham); K.J. Jobst (Karl)

    2012-01-01

    textabstractEarly combined computational and experimental studies by J.K. Terlouw and colleagues propose that low-energy methyl carbamate ions, NH 2COOCH 3 •+ (MC-1), rearrange into distonic ions NH 2C(OH)OCH 2 •+ and hydrogen-bridged radical cations [NH 2C=O-H-OCH 2] •+ (MC-5) en route to the obser

  4. Ultra-Trace Determination of Methyl Carbamate and Ethyl Carbamate in Local Wines by GC-FID Following Pre concentration with C18-SPE

    Supawadee Sarawan

    2014-09-01

    Full Text Available An analytical method is described for ultra-trace determination of methyl carbamate and ethyl carbamate in locally produced fruit wines. The quantitative analysis involves with dichloromethane extraction followed by 30-fold preconcentration using C18 SPE prior to measurement by capillary GC-FID. Under the optimized conditions, a good linearity of their calibration curves was obtained in the range of 0.1-50.0 mg/L with r2 > 0.994. LOD and LOQ were 3.3-16.7 µg/L and 11.1-55.6 µg/L, respectively. The averaged recovery of these carbamates was ranged of 82.2-95.2% with RSD < 8.76%. The procedure was applied to determine both carbamate residues in various local wine samples. It was found that the concentration range of methyl carbamate (6.9-24.1 µg/L was rather fluctuated and higher than that of ethyl carbamate (2.6-4.3 µg/L, suggesting that is a certain residual background contamination naturally occurring in the wine fermentation.

  5. (BOSC) DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PRESTICIDES

    THE US EPA'S N-METHYL CARBAMATE CUMULATIVE RISK ASSESSMENT (NMCRA) ASSESSES THE EFFECT ON ACETYLCHOLINE ESTERASE (AChE) ACTIVITY OF EXPOSURE TO 10 N-METHLY CARBAMATE (NMC)PESTICIDES THROUGH DIETARY, DRINKING WATER, AND RESIDENTIAL EXPOSURES. THESE DATA THUS INFORM, BUT DO NOT COM...

  6. VizieR Online Data Catalog: Rotational transitions of Methyl carbamate (Groner+, 2007)

    Groner, P.; Winnewisser, M.; Medvedev, I. R.; de, F. C. Lucia; Herbst, E.; Sastry, K. V. L. N.

    2008-11-01

    The rotational-torsional spectrum of the syn conformer of methyl carbamate [CH3OC(:O)NH2], an isomer of the essential amino acid glycine [NH2CH2C(:O)OH], has been recorded at room temperature in the spectral region from 79 to 371GHz. Methyl carbamate possesses a methyl group internal rotor, which gives rise to A and E torsional substates, and associated splittings in the rotational spectrum. Almost 6000 new rotational transitions arising from the vibrational ground state have been assigned, about half of them belonging to the E torsional substate. The Fast Scan Submillimeter-wave Spectroscopic Technique (FASSST) spectrometer at the Ohio State University was used for the present measurements (2 data files).

  7. Modeling the vibrational spectrum of 4,4'-diphenylmethane- bis(methyl)carbamate

    Shundalau, M. B.; Pitsevich, G. A.; Ksenofontov, M. A.; Umreiko, D. S.

    2010-07-01

    We present results of ab initio calculations of the structure and vibrational IR spectrum for 4,4'-diphenylmethane-bis(methyl)carbamate (DPMC). Calculations were carried out in the HF/6-311G approximation with subsequent force-field scaling. The calculated characteristics of the vibrational spectrum of DPMC show satisfactory agreement with experimental values, which permits them to be used in spectral and structural analysis

  8. Nonracemic, chiral homoenolate reagents derived from (cycloalk-1-enyl)methyl carbamates and evaluation of their configurational stabilities

    Özlügedik, M.; Kristensen, Jesper Langgaard; Wibbeling, B.;

    2002-01-01

    the products 19/ent-19. Lithiated 2-unsubstituted (cyclopent-1-enyl) methyl carbamates, such as 11a or 11h, epimerise rapidly at -78 °C and the thermodynamically controlled ratio is opposite to the kinetically achieved ratio. High configurational stability was found for the 2-methylcycloalk-1-enyl......-methylcyclopentenyl)methyl and (2-methyl-cyclohexenyl)methyl reagents, established the (1S) configuration of the major lithium compound. Thus, the kinetically controlled deprotonation of the corresponding allyl carbamates removes the (pro-S) proton. Overall, a simple method for the enantioselective synthesis of...

  9. Synthesis of dimethyl carbonate from methyl carbamate and methanol using a Fixed-Bed reactor

    Wang, D. [Zaozhuang University, College of Chemistry, Chemical Engineering and Materials Science, Zaozhuang (China); Zhang, X. [Zaozhuang University, College of Chemistry, Chemical Engineering and Materials Science, Zaozhuang (China); Chinese Academy of Sciences, Institute of Coal Chemistry, State Key Laboratory of Coal Conversion, Taiyuan (China); Wei, W.; Sun, Y. [Chinese Academy of Sciences, Institute of Coal Chemistry, State Key Laboratory of Coal Conversion, Taiyuan (China)

    2012-12-15

    Several mixed oxide catalysts were prepared by coprecipitation for dimethyl carbonate (DMC) synthesis from methyl carbamate and methanol. During the batch process, the DMC yield was below 35 %. In order to minimize the unfavorable thermodynamic equilibrium and side reactions for the DMC synthesis, a fixed-bed reactor was designed. A maximum DMC yield of {proportional_to} 73 % could be realized over a ZnO-Al{sub 2}O{sub 3} catalyst. The effects of reaction conditions for this type of reactor were investigated in detail. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. The Millimeter- and Submillimeter-Wave Spectrum of Methyl Carbamate [CH3OC(:O)NH2

    Groner, Peter; Winnewisser, Manfred; Medvedev, Ivan R.; De Lucia, Frank C.; Herbst, Eric; Sastry, K. V. L. N.

    2007-03-01

    The rotational-torsional spectrum of the syn conformer of methyl carbamate [CH3OC(:O)NH2], an isomer of the essential amino acid glycine [NH2CH2C(:O)OH], has been recorded at room temperature in the spectral region from 79 to 371 GHz. Methyl carbamate possesses a methyl group internal rotor, which gives rise to A and E torsional substates, and associated splittings in the rotational spectrum. Almost 6000 new rotational transitions arising from the vibrational ground state have been assigned, about half of them belonging to the E torsional substate. Along with some earlier data, the newly measured lines were assigned and analyzed efficiently by the integration of two program packages: CAAARS, a suite for visual, interactive mouse-assisted line assignment of asymmetric rotor spectra; and ERHAM, a program that solves the effective Hamiltonian for molecules with up to two periodic large-amplitude internal motions. This Hamiltonian was used to fit 28 spectroscopic parameters for the methyl carbamate ground vibrational state to the observed line positions with a standard deviation of 0.081 MHz. With the determined spectroscopic constants and the available dipole moment components, we are able to predict the transition frequencies and intensities of many additional lines through 400 GHz. Methyl carbamate can now be searched for over a wide frequency range in appropriate interstellar sources such as hot molecular cores.

  11. Benchmark Dose Analysis from Multiple Datasets: The Cumulative Risk Assessment for the N-Methyl Carbamate Pesticides

    The US EPA’s N-Methyl Carbamate (NMC) Cumulative Risk assessment was based on the effect on acetylcholine esterase (AChE) activity of exposure to 10 NMC pesticides through dietary, drinking water, and residential exposures, assuming the effects of joint exposure to NMCs is dose-...

  12. High-performance liquid chromatography multiresidue method for the determination of N-methyl carbamates in fruit and vegetable juices.

    Sánchez-Brunete, Consuelo; Albero, Beatriz; Tadeo, José Luis

    2004-11-01

    A rapid multiresidue method has been developed for the analysis of N-methylcarbamate insecticides (oxamyl, methomyl, propoxur, carbofuran, carbaryl, and methiocarb) in fruit and vegetable juices. The method is based on the adsorption of the N-methyl carbamates in Florisil and the subsequent extraction of pesticides using a low volume of acetone. Residue levels in juice were determined by reversed-phase high-performance liquid chromatography with fluorescence detection after postcolumn derivatization. The separation of carbamates is performed on a C8 column with water-methanol as mobile phase. Recovery studies were performed at 500-, 100-, and 10-ng/ml fortification levels, and average recoveries obtained for carbamates ranged from 79 to 109%, with relative standard deviations between 1.4 and 9.9%. The method was found to be linear over the range assayed from 10 to 1,000 ng/ml, and the detection limits for carbamates varied from 0.8 to 1.9 ng/ml. PMID:15553643

  13. Monitoring of N-methyl carbamate pesticide residues in water using hollow fibre supported liquid membrane and solid phase extraction

    Msagati, Titus A. M.; Mamba, Bhekie B.

    The aim of this work was to develop a method for the determination of N-methyl carbamates in water involving hollow fibre supported liquid membrane (HFSLM) and solid phase extraction (SPE) as sample preparation methods. Four N-methyl carbamate pesticides, aldicarb, carbaryl, carbofuran and methiocarb sulfoxide, were simultaneously extracted and analysed by a liquid chromatograph with a diode array detector (LC-UV/DAD) and a liquid chromatograph coupled to a ion trap quadrupole mass spectrometer (LC-ESI-MS). The high performance liquid chromatography (HPLC) separation of carabamate extracts was performed on a C18 column with water-acetonitrile as the mobile phase. The mass spectrometry analyses were carried out in the positive mode, operating under both the selected ion monitoring (SIM) and full scan modes. The solid phase recoveries of the extracts ranged between 8% and 98%, with aldicarb having the highest recoveries, followed by carbaryl, carbofuran and methiocarb had the lowest recovery. The HFSLM recovery ranged between 8% and 58% and the order of recovery was similar to the SPE trend. Factors controlling the efficiency of the HFSLM extraction such as sample pH, stripping phase pH, enrichment time, stirring speed as well as organic solvent used for entrapment of analytes, were optimised to achieve the highest enrichment factors.

  14. A Novel Synthesis of N-Methyl-N-aryl Carbamates from Aromatic Amines and Dimethyl Carbonate Catalyzed by K2CO3/Bu4NBr

    Zhen Lu SHEN; Xuan Zhen JIANG

    2004-01-01

    A facile synthesis of N-methyl-N-aryl carbamates from aromatic amines and dimethyl carbonate (DMC) has been achieved with high yields in the presence of potassium carbonate (K2CO3) and tetrabutylammonium bromide (Bu4NBr) under solvent-free conditions.

  15. Influence of Solvent on Reaction Path to Synthesis of Methyl N-Phenyl Carbamate from Aniline, CO2 and Methanol

    安华良; 张丽丽; 苑保国; 赵新强; 王延吉

    2014-01-01

    Methyl N-phenyl carbamate (MPC), an important organic chemical, can be synthesized from aniline, CO2 and methanol. Catalyst Cu-Fe/ZrO2-SiO2 was first prepared and its catalytic performance for MPC synthesis was evaluated. Then the influence of solvent on the reaction path of MPC synthesis was investigated. It is found that the reaction intermediate is different with acetonitrile or methanol as a solvent. With acetonitrile as a solvent, the synthesis of MPC follows the reaction path with diphenyl urea as the intermediate, while with methanol as a solvent the reaction occurs via the reaction path with dimethyl carbonate as the intermediate. The catalytic mecha-nism of cooperative catalysis comprising metal sites, Lewis acid sites and Lewis base sites is proposed according to different reaction intermediates.

  16. 氨基酯交换法合成苯氨基甲酸甲酯%Synthesis of Methyl N-phenyl Carbamate by Amino-transesterification

    张光旭; 赵小双; 余东洋; 陈林; 陈建

    2011-01-01

    以PbO经甲醇预处理获得的甲氧基铅为催化剂,苯胺(AN)与氨基甲酸甲酯(MC)为原料酯交换合成苯氨基甲酸甲酯(MPC)。考察了甲醇用量、温度、时间、催化剂用量及原料配比等条件对合成反应的影响。结果表明,m(甲醇)/m(MC)=2、反应温度为150℃、反应时间为5 h、催化剂用量为原料总量的0.1%、m(MC)/m(AN)=2时,MPC的收率可达97.5%,选择性为97.86%。%In the presence of Pb(OCH3)2 catalyst , synthesis of methyl N-phenyl carbamate(MPC) from aniline and methyl carbamate by amino-transesterfication was discussed. The effects of methanol dosage, reaction temperature, reaction time, catalyst dosage and the mass ratios of methyl carbamate to anline on the reaction were studied, and the reaction mechanism over lead methylate catalyst was proposed. Under the optimum reaction conditions, the yield of MPC reached 97. 5% and selectivity of MPC is 97. 86%.

  17. A Novel Non-phosgene Process for the Synthesis of Methyl N-Phenyl Carbamate from Methanol and Phenylurea:Effect of Solvent and Catalyst

    WANG,Xin-Kui(王心葵); YAN,Shi-Run(闫世润); CAO,Yong(曹勇); FAN,Kang-Nian(范康年); HE,He-Yong(贺鹤勇); KANG,Mao-Qing(亢茂青); PENG,Shao-Yi(彭少逸)

    2004-01-01

    A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.

  18. The pH dependence of the mutagenicity of methyl benzimidazol-2-yl carbamate (MBC) towards Aspergillus nidulans (Eidam) Winter and Cladosporium cucumerinum Ellis & Arth.

    Nirenberg, H I; Speakman, J B

    1981-01-01

    The ability of methyl benzimidazol-2-yl carbamate (MBC) to induce point mutations to carboxin and MBC resistance in Aspergillus nidulans (Eidam) Winter and Cladosporium cucumerinum Ellis & Arth. was dependent upon the pH value of the agar medium into which it had been incorporated. The relevance of this in relation to testing chemicals for a possible mutagenic activity with microorganisms is discussed. PMID:7010148

  19. Assignment of the Sub-Millimeter Wave Spectrum of Methyl Carbamate, NH_2COOCH_3, in the First Excited State of the Methyl Group Internal Rotation

    Groner, P.

    2009-06-01

    The rotational spectrum of methyl carbamate in the first excited torsional state (up to 149 GHz) has been analyzed recently for rotational quantum number J up to 20 together with transitions in the ground state. An extended analysis of the rotational spectrum in the ground state between 10 and 371 GHz with over 6000 transitions with J up to 60 has also been published. In the spectra recorded at that time by the FASSST method, about 3000 transitions belonging to the first torsional excited state of the methyl group have now been assigned and analyzed, about half of them belonging to the E torsional species. Both the newly assigned and previously published transitions have been used to fit less than 45 spectroscopic parameters of an effective rotational Hamiltonian for such systems, achieving a dimensionless standard deviation of 1.33. A somewhat unexpected result was the value of the {ρ} parameter of 0.063628(20) which differed significantly from the value obtained for the ground state of 0.058791(15). The discrepancy will be investigated in the near future. Hopefully, a resolution of the problem can be achieved by a combined fit of all excited and ground state transitions using common {ρ} and {β} parameters with {β} as the angle between the {ρ}-axis and the a principal axis. V. Ilyushin, E. Alekseev, J. Demaison, I. Kleiner, J. Mol. Spectrosc. 240, 127 (2006). P. Groner, M. Winnewisser, I. R. Medvedev, F. C. De Lucia, E. Herbst, K. V. L. N. Sastry, Astrophys. J. Suppl. Ser. 169, 28 (2007). P. Groner, J. Chem. Phys. 107, 4483 (1997).

  20. Orally bioavailable pyridine and pyrimidine-based Factor XIa inhibitors: Discovery of the methyl N-phenyl carbamate P2 prime group.

    Corte, James R; Fang, Tianan; Pinto, Donald J P; Orwat, Michael J; Rendina, Alan R; Luettgen, Joseph M; Rossi, Karen A; Wei, Anzhi; Ramamurthy, Vidhyashankar; Myers, Joseph E; Sheriff, Steven; Narayanan, Rangaraj; Harper, Timothy W; Zheng, Joanna J; Li, Yi-Xin; Seiffert, Dietmar A; Wexler, Ruth R; Quan, Mimi L

    2016-05-15

    Pyridine-based Factor XIa (FXIa) inhibitor (S)-2 was optimized by modifying the P2 prime, P1, and scaffold regions. This work resulted in the discovery of the methyl N-phenyl carbamate P2 prime group which maintained FXIa activity, reduced the number of H-bond donors, and improved the physicochemical properties compared to the amino indazole P2 prime moiety. Compound (S)-17 was identified as a potent and selective FXIa inhibitor that was orally bioavailable. Replacement of the basic cyclohexyl methyl amine P1 in (S)-17 with the neutral p-chlorophenyltetrazole P1 resulted in the discovery of (S)-24 which showed a significant improvement in oral bioavailability compared to the previously reported imidazole (S)-23. Additional improvements in FXIa binding affinity, while maintaining oral bioavailability, was achieved by replacing the pyridine scaffold with either a regioisomeric pyridine or pyrimidine ring system. PMID:27073051

  1. Co(II), Ni(II) and Cu(II) complexes of methyl-5-(Phenylthio) benzimidazole-2-carbamate: Molecular structures, spectral and DFT calculations

    Mansour, Ahmed M.; El Bakry, Eslam M.; Abdel-Ghani, Nour T.

    2016-05-01

    [Co(FBZ)2(H2O)]·2NO3·0.5H2O (1), [Ni(FBZ)2X2]·zH2O (X = Cl​-, z = 0.5 (2) and X = CH3COO-, z = 1 (3)) and [Cu(FBZ)2(H2O) (NO3)]·NO3·1.5H2O (4) (FBZ = methyl-5-(Phenylthio) benzimidazole-2-carbamate; Fenbendazole) complexes were synthesized and characterized by elemental analysis, thermal, IR, EPR, UV-Vis, magnetic and conductance measurements. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were carried out at DFT/B3LYP/6-31G∗ level of theory. FBZ behaves as a neutral bidentate ligand via the pyridine-type nitrogen of the benzimidazole moiety and the carbamate group. Three-step ionization with pKa values of 3.38, 4.06 and 10.07 were reported for FBZ. The coordination of FBZ to the metal ions led to an increase in the antibacterial activity against the tested Staphylococcus aureus and Escherichia coli bacteria.

  2. The Preparation and Application of Methyl Carbamate through Alcoholysis of Urea%氨基甲酸甲酯的尿素醇解法制备及其应用研究进展

    侯国宁

    2012-01-01

    As a kind of important fine chemicals, methyl carbamate was widely applied in many areas of chemical in- dustry, which was the research focus of urea downstream at present. The research progress of methyl carbamate through al- coholysis of urea such as normal temperature and pressure catalytic synthesis, medium temperature and medium pressure catalytic synthesis and high pressure synthesis without catalyst were generalized. At the same time, its applications on or- ganic synthesis, medicine, and pesticides were reviewed to have a thorough understanding on methyl carbamate industry.%氨基甲酸甲酯作为一种重要的精细化学品,在众多领域中有着广泛的应用,当前已成为尿素下游领域竞相开发的重点。概述了常温常压催化合成、中温中压催化合成及无催化剂高压合成尿素醇解法生产氨基甲酸甲酯工艺研究进展,同时展望其在有机合成、医药、农药等领域的应用,以期对氨基甲酸甲酯行业的发展有较为深入的了解。

  3. Stereoselective synthesis of highly substituted bicyclic γ-lactones using homoaldol addition of 1-(1-cycloalkenyl)methyl carbamates

    Özlügedik, M.; Kristensen, Jesper Langgaard; Reuber, J.;

    2004-01-01

    Stereoselective addition of aldehydes 4 to metallated 1-(1-cycloalkenyl) methyl N,N-diisopropylcarbamates 1 gave cyclic homoaldol adducts 6. By applying the (-)-sparteine method, enantiomerically enriched products were obtained. These were oxidatively cyclized to diastereomerically pure ¿-lactone...

  4. FT-IR, NBO, HOMO-LUMO, MEP analysis and molecular docking study of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl)phenyl]amino}[(methoxycarbonyl) imino]methyl)carbamate

    Panicker, C. Yohannan; Varghese, Hema Tresa; Narayana, B.; Divya, K.; Sarojini, B. K.; War, Javeed Ahmad; Van Alsenoy, C.; Fun, H. K.

    2015-09-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl) phenyl]amino} [(methoxycarbonyl)imino]methyl)carbamate have been investigated using HF and DFT levels of calculations. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential study was also performed. The first and second hyperpolarizability was calculated in order to find its role in nonlinear optics. Molecular docking studies are also reported. Prediction of Activity Spectra analysis of the title compound predicts anthelmintic and antiparasitic activity as the most probable activity with Pa (probability to be active) value of 0.808 and 0.797, respectively. Molecular docking studies show that both the phenyl groups and the carbonyl oxygens of the molecule are crucial for bonding and these results draw us to the conclusion that the compound might exhibit pteridine reductase inhibitory activity.

  5. Determination of Methyl Carbamate and Ethyl Carbamate in White Liquor by GC-MS%气相色谱-质谱联用测定白酒中的氨基甲酸甲酯和氨基甲酸乙酯

    谭文渊; 袁东; 付大友; 李艳清; 王蓉

    2011-01-01

    建立一种测定白酒中的氨基甲酸甲酯和氨基甲酸乙酯的气相色谱-质谱联用(gas chromatography-massspectrometry,GC-MS)方法。GC-MS条件为:色谱柱HP-55%苯甲基硅氧烷(30.0m×0.25mm,0.25μm),进样1μL(分流比50:1),柱温170℃,质谱离子源温度230℃,四极杆温度150℃,全扫描方式的质量扫描范围m/z 30~500,溶剂延迟3min。样品采用氨基固相小柱萃取净化、氮吹浓缩定容。结果表明:氨基甲酸甲酯和氨基甲酸乙酯在2~30μg/mL范围内线性关系良好,相关系数为0.9923和0.9811,平均回收率为76.10%和75.43%,RSD为4.48%和4.00%。该方法可应用于白酒检测。%A gas chromatography-mass spectrometry(GC-MS) method has been established for the determination of methyl carbamate and ethyl carbamate in white liquor.The GC-MS conditions were column HP-55% phenylmethyl Siloxane(30.0 m × 0.25 mm,0.25μm) as the chromatography column,injection volume of 1μL(split ratio,50:1),column temperature of 170 ℃,ion source temperature of 230 ℃,quadrupole temperature of 150 ℃,mass scanning range(m/z) of 30-500 and solvent delay time of 3 min.The samples were purified by amino solid phase extraction column and then the eluent was evaporated to dryness using nitrogen blow.The results showed that the standard curves of methyl carbamate and ethyl carbamate revealed an excellent linear relationship in the concentration range of 2-30μg/mL with a correlation coefficient of respectively 0.9923 and 0.9811.The average recovery rates of this determination method for methyl carbamate and ethyl carbamate were 76.10% and 75.43% with a RSD of 4.48% and 4.00%,respectively.

  6. Vibrational (FT-IR, FT-Raman) and UV-Visible spectroscopic studies, HOMO-LUMO, NBO, NLO and MEP analysis of Benzyl (imino (1H-pyrazol-1-yl) methyl) carbamate using DFT calculaions

    Shankar Rao, Y. B.; Prasad, M. V. S.; Udaya Sri, N.; Veeraiah, V.

    2016-03-01

    This paper contains a combined experimental and theoretical study of vibrational and electronic properties of Benzyl(imino(1H-pyrazol-1-yl)methyl)carbamate (BPMC) molecule. The FT-IR and FT-Raman spectra of the title molecule in solid phase were recorded in the region 4000-400 cm-1 and 4000-50 cm-1, respectively. The UV absorption spectrum of the studied compound dissolved in ethanol was recorded in the range of 180-400 nm. The molecular geometries calculated using density functional theory (DFT) was compared with available experimental data. The vibrational spectra calculated at the B3LYP/6-31G(d,p) level were compared with the experimental spectra and assignment to each vibrational frequency was assigned on the basis of potential energy distribution (PED). The calculated electronic and nonlinear optical properties of the title molecule were reported. Furthermore, the thermodynamic properties of the molecule were discussed.

  7. Photoinduced chemiluminescence determination of carbamate pesticides.

    Catalá-Icardo, M; Meseguer-Lloret, S; Torres-Cartas, S

    2016-05-11

    A liquid chromatography method with post-column photoinduced chemiluminescence (PICL) detection is proposed for the simultaneous determination of eight carbamate pesticides, namely aldicarb, butocarboxim, ethiofencarb, methomyl, methiocarb, thiodicarb, thiofanox and thiophanate-methyl. After chromatographic separation, quinine (sensitizer) was incorporated and the flow passed through an UV lamp (67 s of irradiation time) to obtain the photoproducts, which reacted with acidic Ce(iv) and provided a CL emission. The PICL method showed great selectivity for carbamate pesticides containing sulphur in their chemical structure. A solid-phase extraction process increased sensitivity (LODs ranging from 0.06 to 0.27 ng mL(-1)) and allowed the carbamate pesticides in surface and ground water samples to be determined, with recoveries in the range 87-110% (except for thiophanate-methyl, whose recoveries were between 60 and 75%). The intra- and inter-day precision was evaluated, with RSD ranging from 1.1 to 7.5% and from 2.6 to 12.3%, respectively. A discussion about the PICL mechanism is also included. PMID:27079156

  8. A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

    Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

  9. Benzimidazole Carbamate Residues in Milk: Detection by SPR Biosensor; using a Modified QuEChERS Method for Extraction

    A surface plasmon resonance (SPR) biosensor screening assay was developed and validated to detect 11 benzimidazole carbamate (BZT) veterinary drug residues in milk. The polyclonal antibody used was raised in sheep against a methyl 5 (6)-[(carboxypentyl)-thio]-2-benzimidazole carbamate protein conjug...

  10. Radiotracer Approaches to Carbamate Insecticide Toxicology

    Methylcarbamates constitute one of the major groups of insecticides. Many unresolved problems in their toxicology may be readily approached with radiotracer studies. Dimethylcarbamates have been prepared with carbonyl-C14-labelling and methylcarbamates withmethyl-, carbonyl-and ring-labelling utilizing carbon-14. The pharmacological action of these.compounds presumably results from acetylcholinesterase inhibition and may involve carbamylation. Reaction of carbonyl- or methyl-labelled carbamates with purified cholinesterase or other esterases would allow a critical examination of this carbamylation reaction and the ease of spontaneous and induced reactivation or decarbamylation. The physiological significance of cholinesterase inhibition might be examined by administering acetate-C14 and analysis for radiolabelled acetylcholine accumulation in nervous tissue, or by utilizing acetyl-C14-choline as the substrate for in vitro determination of the degree of cholinesterase inhibition in tissues of poisoned animals with minimal dilution of the inhibitors and enzymes during analysis. Some progress has been made with radiolabelled materials in investigating the metabolism of carbamate insecticides. Sevin (1-naphthyl methylcarbamate) has been most extensively studied along with its potential hydrolysis products. The assumption that the metabolism of Sevin involves an initial hydrolysis and then further decomposition of the fragments was not supported by carbon-14 studies. The major detoxification mechanism in mammals, and probably also in insects, results from initial oxidative attack on the carbamate by the microsomes in the presence of reduced nicotinamide-adenine dinucleotide phosphate. Sevin is rapidly metabolized in mammals, but the fate of certain of the fragments has not been resolved. Some of the metabolites appear in the milk of lactating animals. One step in the metabolism appears to be formation of the N-methylol derivative. Preliminary studies on the metabolism

  11. Investigations of primary and secondary amine carbamate stability by 1H NMR spectroscopy for post combustion capture of carbon dioxide

    Highlights: ► Carbamate stability constants of series of amines have been measured at (288 to 318) K. ► Standard molar enthalpies and entropies have been determined by van’t Hoff analyses. ► A ΔHmo-ΔSmo plot for carbamate formation gives a linear relationship. ► This relationship provides a guide for the selection of amines for PCC applications. ► Stereochemical effects and intramolecular H-bonding affect carbamate formation. - Abstract: Carbamate formation is one of the major chemical reactions that can occur in solution in the capture of CO2 by amine-based solvents, and carbamate formation makes a significant enthalpy contribution to the absorption-desorption of CO2 that occurs in the absorber/stripper columns of the PCC process. Consequently, the formation of carbamates of selected series of primary and secondary amines over the temperature range (288 to 318) K has been investigated by equilibrium 1H NMR studies, and the stability constants (K9) for the equilibrium: RNH2+HCO3-⇄K9RNHCOO-+H2O are reported. van’t Hoff analyses have resulted in standard molar enthalpies, ΔHmo, and entropies, ΔSmo, of carbamate formation. A ΔHmo-ΔSmo plot generates a linear correlation for carbamate formation (providing a mean standard molar free energy, ΔGmo, for carbamate formation of about −7 kJ · mol−1), and this relationship helps provide a guide to the selection of an amine(s) solvent for CO2 capture, in terms of enthalpy considerations. A linear ΔHmo-ΔSmo plot also occurs for carbamate protonation. The formation of the carbamates has been correlated with systematic changes in composition and structure, and steric effects have been identified by comparing molecular geometries obtained using density functional B3LYP/6-311++G(d,p) calculations. Trends in steric effects have been identified in the series of compounds monoethanolamine (MEA), 1-amino-2-propanol, 2-amino-1-propanol (AP) and 2-amino-2-methyl-1-propanol (AMP). In the case of 2

  12. Carbamate pesticide induced toxic epidermal necrolysis

    Rajendran N

    2001-09-01

    Full Text Available A 36-year-old male alleged to have consumed carbamate pesticide liquid (Baygon@ developed toxic epidermal necrolysis (TEN within twenty-four hours of intake. Though drugs have been commonly incriminated as offending agents for TEN, carbamate pesticide was found to be the causative agent in our case.

  13. PPA-SiO2 Catalyzed Multi-component Synthesis of N-[α-(β-Hydroxy-α-naphthyl)(benzyl)]O-Alkyl Carbamate Derivatives

    SHATERIAN,Hamid Reza; HOSSEINIAN,Asghar; GHASHANG,Majid

    2009-01-01

    Silica-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the multi-component condensation reaction of benzaldehydes,2-naphthol,and methyl/benzyl carbamate to afford the corresponding N-[α-(β-hydroxy-α-naphthyl)(benzyl)]O-alkyl carbamate derivatives in good to excellent yields.This new approach consistently has the advantage of short reaction time,high conversions,clean reaction profiles,and simple experimental and work-up procedures.

  14. Carbamic acid and carbamate formation in NH{3}:CO{2} ices - UV irradiation versus thermal processes

    Bossa, J. B.; Theulé, P.; Duvernay, F.; Borget, F.; Chiavassa, T.

    2008-12-01

    Context: We study carbamic acid [ NH{2}COOH] and ammonium carbamate [ NH{2}COO-] [ NH{4}+] formation in interstellar ice analogs. Aims: We demonstrate how carbamic acid [ NH{2}COOH] and ammonium carbamate [ NH{2}COO-] [ NH{4}+] can be formed from both thermal reactions and energetic photons in an NH{3}:CO{2} ice mixture. Methods: Infrared and mass spectroscopy are used to monitor NH{3}:CO{2} ice mixture evolution during both warming and VUV photon irradiation. Results: Carbamic acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH{3} and CO{2} above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into carbamic acid formation in interstellar ices. Conclusions: We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, carbamic acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.

  15. Organophosphorus and carbamate insecticide poisoning.

    Vale, Allister; Lotti, Marcello

    2015-01-01

    Both organophosphorus (OP) and carbamate insecticides inhibit acetylcholinesterase (AChE), which results in accumulation of acetylcholine (ACh) at autonomic and some central synapses and at autonomic postganglionic and neuromuscular junctions. As a consequence, ACh binds to, and stimulates, muscarinic and nicotinic receptors, thereby producing characteristic features. With OP insecticides (but not carbamates), "aging" may also occur by partial dealkylation of the serine group at the active site of AChE; recovery of AChE activity requires synthesis of new enzyme in the liver. Relapse after apparent resolution of cholinergic symptoms has been reported with OP insecticides and is termed the intermediate syndrome. This involves the onset of muscle paralysis affecting particularly upper-limb muscles, neck flexors, and cranial nerves some 24-96 hours after OP exposure and is often associated with the development of respiratory failure. OP-induced delayed neuropathy results from phosphorylation and subsequent aging of at least 70% of neuropathy target esterase. Cramping muscle pain in the lower limbs, distal numbness, and paresthesiae are followed by progressive weakness, depression of deep tendon reflexes in the lower limbs and, in severe cases, in the upper limbs. The therapeutic combination of oxime, atropine, and diazepam is well established experimentally in the treatment of OP pesticide poisoning. However, there has been controversy as to whether oximes improve morbidity and mortality in human poisoning. The explanation may be that the solvents in many formulations are primarily responsible for the high morbidity and mortality; oximes would not be expected to reduce toxicity in these circumstances. even if given in appropriate dose. PMID:26563788

  16. New Water-Soluble Carbamate Ester Derivatives of Resveratrol

    Andrea Mattarei

    2014-10-01

    Full Text Available Low bioavailability severely hinders exploitation of the biomedical potential of resveratrol. Extensive phase-II metabolism and poor water solubility contribute to lowering the concentrations of resveratrol in the bloodstream after oral administration. Prodrugs may provide a solution—protection of the phenolic functions hinders conjugative metabolism and can be exploited to modulate the physicochemical properties of the compound. We report here the synthesis and characterization of carbamate ester derivatives of resveratrol bearing on each nitrogen atom a methyl group and either a methoxy-poly(ethylene glycol-350 (mPEG-350 or a butyl-glucosyl promoiety conferring high water solubility. Ex vivo absorption studies revealed that the butyl-glucosyl conjugate, unlike the mPEG-350 one, is able to permeate the intestinal wall. In vivo pharmacokinetics confirmed absorption after oral administration and showed that no hydrolysis of the carbamate groups takes place. Thus, sugar groups can be attached to resveratrol to obtain soluble derivatives maintaining to some degree the ability to permeate biomembranes, perhaps by facilitated or active transport.

  17. Computational study of structural properties of lithium cation complexes with carbamate-modified disiloxanes.

    Jeschke, Steffen; Wiemhöfer, Hans-Dieter; Mück-Lichtenfeld, Christian

    2014-07-21

    Lithium cation solvation structures [Li(S)(n=1-4)](+) with ligands of cyclic or noncyclic carbamate-modified disiloxanes are optimized at B3LYP level of theory and compared to their corresponding simplified carbamates and to the organic carbonates ethylene carbonate (EC) and dimethyl carbonate (DMC). The electrostatic potentials (ESP) of these investigated carbonyl-containing solvents are mapped on the electron density surface. The maximum ESP is located at the C=O-oxygen, whereas the disiloxane functionality represents an unpolar residue. Natural Bond Orbitals (NBO) analysis reveals strong n(N) →π(C[double bond, length as m-dash]O) donor-acceptor interactions in carbamates which outrun dipolar properties. As a result, higher total binding energies (ΔE(B)) for solvation of Li(+) in carbamates (-148 kcal mol(-1)) are found than for carbonates (-137 kcal mol(-1)). Furthermore, the disiloxane moiety with its Si-O bond is stabilized by n(O) →σ*(Si-C) hyperconjugation that provides additional electron density to a nearby SiCH3 methyl group thus supporting an additional SiCH2-H...Li(+) coordination. The formation of all investigated solvation structures is exothermic. Owing to steric hindrance of noncyclic carbonyl-containing ligands and the bulky disiloxane functionality, the solvation structure [Li(S)3](+) is the preferred structure according to Gibbs free energy ΔG(B) results. PMID:24914737

  18. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted phenylimino carbamate... Specific Chemical Substances § 721.2025 Substituted phenylimino carbamate derivative. (a) Chemical... as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject to reporting under...

  19. 21 CFR 520.434 - Chlorphenesin carbamate tablets.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chlorphenesin carbamate tablets. 520.434 Section... Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin carbamate. (b) Sponsor. See No. 000009 in § 510.600(c) of this chapter. (c) Conditions of use in...

  20. Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates.

    Krátký, Martin; Štěpánková, Šárka; Vorčáková, Katarína; Švarcová, Markéta; Vinšová, Jarmila

    2016-01-01

    Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thio)carbamates were investigated using Ellman's method for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). O-Aromatic (thio)carbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE were mostly lower than those obtained for AChE; four derivatives showed distinct selectivity for BChE. All of the (thio)carbamates produced a stronger inhibition of AChE than rivastigmine, and five of them inhibited BChE more effectively than both established drugs rivastigmine and galantamine. In general, 5-chloro-2-hydroxy-N-[4-(trifluoromethyl)-phenyl]benzamide, 2-hydroxy-N-phenylbenzamide as well as N-methyl-N-phenyl carbamate derivatives led to the more potent inhibition. O-{4-Chloro-2-[(4-chlorophenyl)carbamoyl]phenyl} dimethylcarbamothioate was identified as the most effective AChE inhibitor (IC50 = 38.98 µM), while 2-(phenylcarbamoyl)phenyl diphenylcarbamate produced the lowest IC50 value for BChE (1.60 µM). Results from molecular docking studies suggest that carbamate compounds, especially N,N-diphenyl substituted representatives with considerable portion of aromatic moieties may work as non-covalent inhibitors displaying many interactions at peripheral anionic sites of both enzymes. Mild cytotoxicity for HepG2 cells and consequent satisfactory calculated selectivity indexes qualify several derivatives for further optimization. PMID:26875979

  1. Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamates

    Thais C. M. Noguiera

    2015-07-01

    Full Text Available The crystal structures of three methylated hydrazine carbamate derivatives prepared by multi-step syntheses from l-serine are presented, namely benzyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C20H20N4O4, tert-butyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C17H22N4O4, and tert-butyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methylation reaction. In each crystal structure, the molecules are linked into chains by O—H...O hydrogen bonds, but with significant differences between them.

  2. Optimization of 1,2,5-Thiadiazole Carbamates as Potent and Selective ABHD6 Inhibitors #

    Patel, Jayendra Z.; Nevalainen, Tapio J.; Savinainen, Juha R.; Adams, Yahaya; Laitinen, Tuomo; Runyon, Robert S.; Vaara, Miia; Ahenkorah, Stephen; Kaczor, Agnieszka A.; Navia-Paldanius, Dina; Gynther, Mikko; Aaltonen, Niina; Joharapurkar, Amit A.; Jain, Mukul R.; Haka, Abigail S.; Maxfield, Frederick R.; Laitinen, Jarmo T.; Parkkari, Teija

    2015-01-01

    At present, inhibitors of α/β-hydrolase domain 6 (ABHD6) are viewed as a promising approach to treat inflammation and metabolic disorders. This article describes the optimization of 1,2,5-thiadiazole carbamates as ABHD6 inhibitors. Altogether, 34 compounds were synthesized and their inhibitory activity was tested using lysates of HEK293 cells transiently expressing human ABHD6 (hABHD6). Among the compound series, 4-morpholino-1,2,5-thiadiazol-3-yl cyclooctyl(methyl)carbamate (JZP-430, 55) potently and irreversibly inhibited hABHD6 (IC50 44 nM) and showed good selectivity (∼230 fold) over fatty acid amide hydrolase (FAAH) and lysosomal acid lipase (LAL), the main off-targets of related compounds. Additionally, activity-based protein profiling (ABPP) indicated that compound 55 (JZP-430) displayed good selectivity among the serine hydrolases of mouse brain membrane proteome. PMID:25504894

  3. CUMULATIVE EFFECTS OF ORGANOPHOSPHORUS OR CARBAMATE PESTICIDES.

    This book chapter strives to summarize the body of literature exploring the toxic interaction of organophosphorus and carbamate pesticides in mixtures. This review represents one of the only reviews of the subject that has been published within the last 20 years. Specifically, th...

  4. Amino Acid Carbamates As Prodrugs Of Resveratrol

    Andrea Mattarei; Michele Azzolini; Martina La Spina; Mario Zoratti; Cristina Paradisi; Lucia Biasutto

    2015-01-01

    Resveratrol (3, 5, 4′-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) lin...

  5. Amino Acid Carbamates As Prodrugs Of Resveratrol.

    Mattarei, Andrea; Azzolini, Michele; La Spina, Martina; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia

    2015-01-01

    Resveratrol (3, 5, 4'-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) linkage with a natural amino acid (Leu, Ile, Phe, Thr) to prevent conjugation and modulate the physicochemical properties of the molecule. We also report a convenient, high-yield protocol to obtain derivatives of this type. The new carbamate ester derivatives are stable at pH 1, while they undergo slow hydrolysis at physiological pH and hydrolyse with kinetics suitable for use in prodrugs in whole blood. After administration to rats by oral gavage the isoleucine-containing prodrug was significantly absorbed, and was present in the bloodstream as non-metabolized unaltered or partially deprotected species, demonstrating effective shielding from first-pass metabolism. We conclude that prodrugs based on the N-monosubstituted carbamate ester bond have the appropriate stability profile for the systemic delivery of phenolic compounds. PMID:26463125

  6. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    Li-Si Huang; Fei He; Hui Huang; Xiao-Yong Zhang; Shu-Hua Qi

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (−)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (−)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendrane...

  7. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    Huang, Li-Si; He, Fei; Huang, Hui; Zhang, Xiao-yong; Qi, Shu-Hua

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (−)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (−)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. ...

  8. Vinyl carbamate epoxide, a major strong electrophilic, mutagenic and carcinogenic metabolite of vinyl carbamate and ethyl carbamate (urethane).

    Park, K K; Liem, A; Stewart, B C; Miller, J A

    1993-03-01

    Vinyl carbamate epoxide (VCO) was found to possess strong electrophilic, mutagenic and carcinogenic activities. It reacted with water at 37 degrees C and pH 7.4 (phosphate buffer) to form glycolaldehyde and several related reducing compounds; none of these products were mutagenic for Salmonella typhimurium TA1535. Under these conditions VCO had a half-life (determined chemically and mutagenically) of approximately 10.5 min. This half-life was progressively lowered by increasing concentrations of chloride ion (liver, serum and isotonic levels). This ion reacted with VCO to form chloroacetaldehyde. VCO also reacted with other nucleophiles such as glutathione, DNA and its constituent guanine and adenine bases. The purine adducts formed by VCO in DNA in vitro and in vivo were released by weak acid treatment and consisted of 7-(2'-oxoethyl)guanine and N2,3-ethenoguanine as major products with 1,N6-ethenoadenine as a minor product. VCO was a strong direct mutagen in Salmonella typhimurium TA1535 and TA100 but was only weakly active in the TA98 mutant. VCO was a stronger initiator of carcinogenesis in the skin of CD-1 mice and in the liver of infant male B6C3F1 mice than its metabolic precursors vinyl carbamate (VC) and ethyl carbamate (EC). Unlike VC and EC, VCO was a strong complete carcinogen in the skin of CD-1 mice and induced papillomas and carcinomas following repetitive administration of sub-ulcerogenic doses. VCO also exhibited some carcinogenic activity in the lungs of mice and in the s.c. and mammary tissue of female Sprague-Dawley rats. These data and those from other recent studies support the conclusion that VCO is a major strong electrophilic, mutagenic and carcinogenic metabolite of EC and VC in the mouse. PMID:8453720

  9. Chemoselective Synthesis of Carbamates using CO2 as Carbon Source.

    Riemer, Daniel; Hirapara, Pradipbhai; Das, Shoubhik

    2016-08-01

    Synthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmospheric pressure. This methodology can also be applied to protect the amino group in amino acids and peptides, and also to synthesize important pharmaceuticals. PMID:27376902

  10. 76 FR 34200 - Land Disposal Restrictions: Revision of the Treatment Standards for Carbamate Wastes

    2011-06-13

    ... Standards for Carbamate Wastes AGENCY: Environmental Protection Agency. ACTION: Proposed rule. SUMMARY: The...) treatment standards for hazardous wastes from the production of carbamates and carbamate commercial chemical... carbamate wastes must be treated to meet numeric concentration limits before they can be land...

  11. Select small core structure carbamates exhibit high contact toxicity to "carbamate-resistant" strain malaria mosquitoes, Anopheles gambiae (Akron.

    Dawn M Wong

    Full Text Available Acetylcholinesterase (AChE is a proven target for control of the malaria mosquito (Anopheles gambiae. Unfortunately, a single amino acid mutation (G119S in An. gambiae AChE-1 (AgAChE confers resistance to the AChE inhibitors currently approved by the World Health Organization for indoor residual spraying. In this report, we describe several carbamate inhibitors that potently inhibit G119S AgAChE and that are contact-toxic to carbamate-resistant An. gambiae. PCR-RFLP analysis was used to confirm that carbamate-susceptible G3 and carbamate-resistant Akron strains of An. gambiae carry wild-type (WT and G119S AChE, respectively. G119S AgAChE was expressed and purified for the first time, and was shown to have only 3% of the turnover number (k(cat of the WT enzyme. Twelve carbamates were then assayed for inhibition of these enzymes. High resistance ratios (>2,500-fold were observed for carbamates bearing a benzene ring core, consistent with the carbamate-resistant phenotype of the G119S enzyme. Interestingly, resistance ratios for two oxime methylcarbamates, and for five pyrazol-4-yl methylcarbamates were found to be much lower (4- to 65-fold. The toxicities of these carbamates to live G3 and Akron strain An. gambiae were determined. As expected from the enzyme resistance ratios, carbamates bearing a benzene ring core showed low toxicity to Akron strain An. gambiae (LC(50>5,000 μg/mL. However, one oxime methylcarbamate (aldicarb and five pyrazol-4-yl methylcarbamates (4a-e showed good to excellent toxicity to the Akron strain (LC(50 = 32-650 μg/mL. These results suggest that appropriately functionalized "small-core" carbamates could function as a resistance-breaking anticholinesterase insecticides against the malaria mosquito.

  12. Tandem Mass Spectrometry Measurement of the Collision Products of Carbamate Anions Derived from CO2 Capture Sorbents: Paving the Way for Accurate Quantitation

    Jackson, Phil; Fisher, Keith J.; Attalla, Moetaz Ibrahim

    2011-08-01

    The reaction between CO2 and aqueous amines to produce a charged carbamate product plays a crucial role in post-combustion capture chemistry when primary and secondary amines are used. In this paper, we report the low energy negative-ion CID results for several anionic carbamates derived from primary and secondary amines commonly used as post-combustion capture solvents. The study was performed using the modern equivalent of a triple quadrupole instrument equipped with a T-wave collision cell. Deuterium labeling of 2-aminoethanol (1,1,2,2,-d4-2-aminoethanol) and computations at the M06-2X/6-311++G(d,p) level were used to confirm the identity of the fragmentation products for 2-hydroxyethylcarbamate (derived from 2-aminoethanol), in particular the ions CN-, NCO- and facile neutral losses of CO2 and water; there is precedent for the latter in condensed phase isocyanate chemistry. The fragmentations of 2-hydroxyethylcarbamate were generalized for carbamate anions derived from other capture amines, including ethylenediamine, diethanolamine, and piperazine. We also report unequivocal evidence for the existence of carbamate anions derived from sterically hindered amines ( Tris(2-hydroxymethyl)aminomethane and 2-methyl-2-aminopropanol). For the suite of carbamates investigated, diagnostic losses include the decarboxylation product (-CO2, 44 mass units), loss of 46 mass units and the fragments NCO- ( m/z 42) and CN- ( m/z 26). We also report low energy CID results for the dicarbamate dianion (-O2CNHC2H4NHCO{2/-}) commonly encountered in CO2 capture solution utilizing ethylenediamine. Finally, we demonstrate a promising ion chromatography-MS based procedure for the separation and quantitation of aqueous anionic carbamates, which is based on the reported CID findings. The availability of accurate quantitation methods for ionic CO2 capture products could lead to dynamic operational tuning of CO2 capture-plants and, thus, cost-savings via real-time manipulation of solvent

  13. Mechanism of action of organophosphorus and carbamate insecticides.

    Fukuto, T R

    1990-01-01

    Organophosphorus and carbamate insecticides are toxic to insects and mammals by virtue of their ability to inactivate the enzyme acetylcholinesterase. This review addresses the mechanism of inhibition of acetylcholinesterase by organophosphorus and carbamate esters, focusing on structural requirements necessary for anticholinesterase activity. The inhibition of acetylcholinesterase by these compounds is discussed in terms of reactivity and steric effects. The role of metabolic activation or d...

  14. Physicochemical studies of the carbamate-CO2-solvent system

    The formation of carbamate from CO2 and the various amine solutions has been investigated for the purpose of elucidating the structure of the species generated in the reaction. The amine solutions used were 1 and 2 molar solutions of di-n-butylamine (DNBA) in triethylamine (TEA), pure DNBA and pure TEA. It has been found that the nonaqueous solvent participates in the formation of carbamate in 1 and 2M-DNBA/TEA solutions as a proton acceptor in DNBA-carbamate formation. However, due to the high concentration of the solutions and the basicities of the amines, a significant amount of DNBA which does not form the DNBA-carbamate anion is also found to be participating as a proton acceptor. Pure TEA absorbs only 1/60 of the absorption by pure DNBA. The extent of TEA participation in the CO2-absorption process other than as a proton acceptor in DNBA-carbamate is negligible. The formation of carbamic acid and zwitterion have been found unlikely. 7 tables, 15 figs

  15. Wildlife mortality attributed to organophosphorus and carbamate pesticides

    Glaser, L.C.

    1995-01-01

    Organophosphorus (OP) and carbamate pesticides are used widely in agricultural and residential applications as insecticides, herbicides, fungicities. and rodenticides. This family of chemicals replaced the organochlorine pesticides banned for use in the United States in the 1970's. Unlike organochlorine pesticides, which are long-lived in the environment and cause biological damage when they accumulate in an organism's system over time. OP and carbamate pesticides are short-lived in the environment and fast-acting on their 'target pest.' Direct mortality of wildlife from organochlorine pesticides was uncommon (Hayes and Wayland 1975): however, mortality is the primary documented effect on wildlife from OP and carbamate pesticides (Grue et al. 1983). Organophosphorus and carbamate pesticide toxicity is not specific to a target 'pest,' and lethal effects are seen in nontarget organisms: birds appear to be the most sensitive class of animals affected by these pesticides. Organophosphorus and carbamate pesticides primainly affect the nervous system by inhibiting acetylcholinesterase (AChE) enzyme activity. This enzyme's main function in the nervous system is to break down the neurotransmitter acetylcholine. When AChE is altered by OP and carbamate pesticides, it cannot perform this breakdown function and acetylcholine accumulates. Acetylcholine accumulation increases nerve impulse transmission and leads to nerve exhaustion and. ultimately, failure of the nervous system. When the nervous system fails, muscles do not receive the electrical input they require to move. The respiratory muscles are the most critical muscle group affected, and respiratory paralysis is often the immediate cause of death.

  16. Synthesis and reactivity of cyclic-carbamate derivatives%环状氨基甲酸酯衍生物的合成及反应研究

    王静; 郭爽; 王家喜

    2011-01-01

    Cyclic carbamate has been prepared by the reaction of ethanolamine with dimethyl carbonate as raw material and zinc acetate as catalyst. The cyclic carbamate reacted with methyl acrylate producing methyl 3- (2-oxo-oxazolidin-3-yl) propanoate, which reacted with n-butylamine and 1,6-hexanediamine to give mono and bis cyclic carbamate derivatives. The attack of amine to carbonyl of heterocyclic ring of carbamate produced the hydroxylethyl substituted urea, while the attack to carbon-oxygen bond generated carbamic acid, which further underwent dehydration forming cyclic urea and/or de-carbon dioxide forming polyamine. The products were characterized by NMR and FT-IR. The reaction mechanism is finally proposed.%以乙醇胺和碳酸二甲酯为原料,在醋酸锌的催化下合成环状氨基甲酸酯,与丙烯酸甲酯反应制备3-(2-噁唑烷酮)丙酸甲酯,在K2CO3催化下进一步与正丁胺、1,6-己二胺发生酰胺化反应,得到了单、双环状氨基甲酸酯衍生物.有机胺与环状氨基甲酸酯的羰基反应形成羟乙基取代脲,与烷氧基反应形成开环的胺基甲酸,该化合物进一步脱水形成环状脲,脱二氧化碳形成多胺化合物.用NMR和红外谱图对开环产物进行表征,并初步探讨了其反应历程.

  17. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata.

    Huang, Li-Si; He, Fei; Huang, Hui; Zhang, Xiao-Yong; Qi, Shu-Hua

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (-)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (-)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1-5 were conjectured. PMID:22423284

  18. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    Li-Si Huang

    2012-01-01

    Full Text Available Five carbamate derivatives, obtucarbamates C and D (1, 2, dimethyl ((carbonylbis(azanediylbis(2-methyl-5,1-phenylenedicarbamate (3, obtucarbamates A and B (4, 5, and four aromadendrane-type sesquiterpenoids, (+-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6, (−-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7, (−-4α,10β-aromadendranediol (8, (+-4β,10β-aromadendranediol (9 were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1–5 were conjectured.

  19. Solubility improvement of an anthelmintic benzimidazole carbamate by association with dendrimers

    Fernandez, L.; Sigal, E.; Santo, M., E-mail: msanto@exa.unrc.edu.ar [Departamento de Fisica, Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto (Argentina); Otero, L.; Silber, J. J. [Departamento de Quimica. Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Rio Cuarto (Argentina)

    2011-10-15

    The improvement of aqueous solubility of methyl (5-[propylthio]-1H-benzimidazole-2-yl) carbamate, albendazole (ABZ) using polyamidoamine (PAMAM) dendrimers as solubility enhancers was investigated. Full generation PAMAM dendrimers with amine terminal groups, (G3), with hydroxyl terminal groups (G3OH) and half generation PAMAM dendrimers with carboxylate terminal groups (G2.5 and G3.5), were chosen for this study. The nature of dendrimer-ABZ association was investigated by UV absorption, fluorescence emission measurements and by {sup 1}H-NMR spectroscopy. The results obtained show that these polymeric structures have the capacity to enhance the solubility of ABZ, both lipophilic and specific hydrogen bond interactions contributing to the guest-host association. Although all studied dendrimers have hydrophobic internal nanoenvironments with similar dimensions, their surfaces differ significantly and the nature and the localization of the interactions involved in ABZ-dendrimer association depend on the type of terminal groups. (author)

  20. [Formation of ethyl carbamate in umeshu (plum liqueur)].

    Suzuki, K; Kamimura, H; Ibe, A; Tabata, S; Yasuda, K; Nishijima, M

    2001-12-01

    Samples of umeshu, a Japanese plum liqueur made from unripe plums, shochu and crystal sugar, were stored under fluorescent light, in the dark and in the refrigerator. The amount of ethyl carbamate formed in umeshu exposed to light or room temperature was larger than that in the dark or at low temperature. The amount of ethyl carbamate formed in umeshu to which cyanide had been added was larger than that in the absence of added cyanide. Thus, the amount of ethyl carbamate formed in the umeshu was increased by not only light and higher temperature, but also cyanide. Samples of model alcoholic beverages were stored under various conditions using red, yellow and blue cellophanes. The amount of ethyl carbamate formed in the model alcoholic beverage with blue cellophane was larger than in the cases of red and yellow cellophanes. It was found that the amount of ethyl carbamate formed in the model alcoholic beverage was increased by light in the wavelength range of 375-475 nm. PMID:11875819

  1. 76 FR 34147 - Land Disposal Restrictions: Revision of the Treatment Standards for Carbamate Wastes

    2011-06-13

    ... carbamates (61 FR 15583). These treatment standards were based on data for similar wastes for which EPA... CFR 268.48. EPA promulgated numeric treatment standards for these carbamate wastes in 1994 (59 FR... UHC carbamates. As a result, EPA promulgated an emergency rule in 1996 (61 FR 43924, August 26,...

  2. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Perfluoroalkyl aromatic carbamate... Significant New Uses for Specific Chemical Substances § 721.7200 Perfluoroalkyl aromatic carbamate modified...) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  3. Immobilization of acetylcholinesterase via biocompatible interface of silk fibroin for detection of organophosphate and carbamate pesticides

    Xue, Rui; Kang, Tian-Fang; Lu, Li-Ping; Cheng, Shui-Yuan

    2012-06-01

    An amperometric biosensor for the detection of organophosphate and carbamate pesticides was developed based on the immobilization of acetylcholinesterase (AChE) on regenerated silk fibroin (SF) matrix by non-covalent adsorption. SF and AChE were coated sequentially on the surface of the glassy carbon electrode (GCE) which was modified with multiwall carbon nanotube (MWNTs). The obtained biosensor was denoted as AChE-SF/MWNTs/GCE. The atomic force microscopy images showed that the SF matrix provided a more homogeneous interface for the AChE immobilization. The aggregation of immobilizing AChE was therefore avoided. The cyclic voltammogram of thiocholine at this biosensor exhibited a well defined oxidation peak at 0.667 V (vs. SCE). The inhibition rate of methyl parathion to the immobilized AChE was proportional to the logarithm of the concentration of methyl parathion over the range of the concentration of methyl parathion from 3.5 × 10-6 to 2.0 × 10-3 M with a detection limit of 5.0 × 10-7 M. Similarly, the linearly response range of carbaryl was from 1.0 × 10-7 to 3.0 × 10-5 M with a detection limit of 6.0 × 10-8 M. The experimental results indicate that AChE not only can be immobilized steadily on the SF matrix, but also the bioactivity of immobilizing AChE can be preserved effectively.

  4. Growth and characterization of organic single crystal benzyl carbamate

    Bala Solanki, S. Siva; Perumal, Rajesh Narayana; Suthan, T.; Bhagavannarayana, G.

    2015-10-01

    Benzyl carbamate single crystal is grown by a solution and vertical Bridgman technique for the first time. The cell parameters and morphologies are assessed from single crystal X-ray diffraction analysis. High resolution X-ray diffraction analysis indicates the crystalline perfection of the grown benzyl carbamate crystal. Fourier Transforms Infrared spectroscopy study has been applied to arrive at the different functional groups. Thermo gravimetric analysis and differential scanning calorimetry are used to study its thermal behavior. The microhardness test is carried out and the load dependent hardness is measured.

  5. Comparative MO investigation of hindered rotation and thermal decomposition of carbamates and thiocarbamates

    Investigation of hindered rotation in carbamates reveals the high flexibility and ionic character of the C-N bond as compared to common amides. This flexibility decreases in the case of thiocarbamates. The mechanism of activation of carbamates has been explored. Computations have proven the possibility of formation of an intramolecular H-bond in carbamates and thiocarbamates. This intramolecular H-bond is formed immediately after protonation of the carbamate. The possibility of formation of zwitterions as intermediates in the decomposition of carbamic and dithiocarbamic acids is discussed. (Auth.)

  6. Induction of Tibial Dyschondroplasia by Carbamate and Thiocarbamate Pesticides

    Tibial dyschondroplasia (TD) is a major poultry leg problem the natural etiology of which is unknown. Certain dithiocarbamate pesticides such as tetramethyl thiuram disulfide (thiram) have been shown to induce the disease in chickens. Since many different carbamate and thiocarbamate chemicals are ...

  7. NMDA antagonists exert distinct effects in experimental organophosphate or carbamate poisoning in mice

    Organophosphate (OP) and carbamate acetylcholinesterase (AChE) inhibitors produce seizures and lethality in mammals. Anticonvulsant and neuroprotective properties of N-methyl-D-aspartate (NMDA) antagonists encourage the investigation of their effects in AChE inhibitor-induced poisonings. In the present study, the effects of dizocilpine (MK-801, 1 mg/kg) or 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 10 mg/kg), alone or combined with muscarinic antagonist atropine (1.8 mg/kg), on convulsant and lethal properties of an OP pesticide dichlorvos or a carbamate drug physostigmine, were studied in mice. Both dichlorvos and physostigmine induced dose-dependent seizure activity and lethality. Atropine did not prevent the occurrence of convulsions but decreased the lethal effects of both dichlorvos and physostigmine. MK-801 or CPP blocked or attenuated, respectively, dichlorvos-induced convulsions. Contrariwise, NMDA antagonists had no effect in physostigmine-induced seizures or lethality produced by dichlorvos or physostigmine. Concurrent pretreatment with atropine and either MK-801 or CPP blocked or alleviated seizures produced by dichlorvos, but not by physostigmine. Both MK-801 and CPP co-administered with atropine enhanced its antilethal effects in both dichlorvos and physostigmine poisoning. In both saline- and AChE inhibitor-treated mice, no interaction of the investigated antidotes with brain cholinesterase was found. The data indicate that both muscarinic ACh and NMDA receptor-mediated mechanisms contribute to the acute toxicity of AChE inhibitors, and NMDA receptors seem critical to OP-induced seizures

  8. Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates

    Martin Krátký

    2016-02-01

    Full Text Available Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thiocarbamates were investigated using Ellman’s method for their ability to inhibit acetylcholinesterase (AChE and butyrylcholinesterase (BChE. O-Aromatic (thiocarbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE were mostly lower than those obtained for AChE; four derivatives showed distinct selectivity for BChE. All of the (thiocarbamates produced a stronger inhibition of AChE than rivastigmine, and five of them inhibited BChE more effectively than both established drugs rivastigmine and galantamine. In general, 5-chloro-2-hydroxy-N-[4-(trifluoromethyl-phenyl]benzamide, 2-hydroxy-N-phenylbenzamide as well as N-methyl-N-phenyl carbamate derivatives led to the more potent inhibition. O-{4-Chloro-2-[(4-chlorophenylcarbamoyl]phenyl} dimethylcarbamothioate was identified as the most effective AChE inhibitor (IC50 = 38.98 µM, while 2-(phenylcarbamoylphenyl diphenylcarbamate produced the lowest IC50 value for BChE (1.60 µM. Results from molecular docking studies suggest that carbamate compounds, especially N,N-diphenyl substituted representatives with considerable portion of aromatic moieties may work as non-covalent inhibitors displaying many interactions at peripheral anionic sites of both enzymes. Mild cytotoxicity for HepG2 cells and consequent satisfactory calculated selectivity indexes qualify several derivatives for further optimization.

  9. Synthesis of Novel Cellulose Carbamates Possessing Terminal Amino Groups and Their Bioactivity.

    Ganske, Kristin; Wiegand, Cornelia; Hipler, Uta-Christina; Heinze, Thomas

    2016-03-01

    Cellulose phenyl carbonates are an excellent platform to synthesize a broad variety of soluble and functional cellulose carbamates. In this study, the synthesis of cellulose carbamates with terminal amino groups, namely ω-aminoethylcellulose- and ω-aminoethyl-p-aminobenzyl-cellulose carbamate, is discussed. The products are well soluble and their structures can be clearly described by NMR spectroscopy. The cellulose carbamates exhibit a bactericide and fungicide activity in vitro. The ω-aminoethylcellulose carbamate possesses a strong activity against Candida albicans and Staphylococcus aureus (IC50 of 0.02 mg mL(-1) and 0.05 mg mL(-1)). The antimicrobial activity and cytotoxicity can be improved by p-amino-benzylamine (ABA) as an additional substituent. The mixed cellulose carbamate exhibits a high biocompatibility (LC50 of 3.18 mg mL(-1)) and forms films on cotton and PES, which exhibit a strong activity against S. aureus and Klebsiella pneumoniae. PMID:26612063

  10. The Target of Benzimidazole Carbamate Against Cysticerci cellulosae

    LI Qing-zhang; HAO Yan-hong; GAO Xue-jun; GAO Wen-xue; ZHAO Bing

    2007-01-01

    To study the target of benzimidazole carbamate drugs against Cysticerci cellulosae and give a theoretical basis for type evolution and new drug design, the changes of key enzyme activities and metabolite contents in the pathway of energy metabolism in C. cellulosae in vitro and in vivo were tested with albendazole and oxfendazole, respectively. Both albendazole and oxfendazole inhibited the pathways of anaerobic glycolysis, partial inversed tricarboxylic acid cycle of Taenia Solium oncosphere, immature and mature Cysticerci in vitro, and immature and mature Cysticerci in vivo to a certain degree, and enhanced fat decomposing, amino acid decomposing, xanthine decomposing metabolism, and on the other hand, the absorption of glucose was hindered; furthermore, both albendazole and oxfendazole inhibited the activities of the fumaric reductase (FR) complex noncompetently in vitro. Benzimidazole carbamate drugs could inhibit the activities of FR complex noncompetently and hinder the absorption of glucose.

  11. Organophosphate and carbamate insecticides in agricultural waters and cholinesterase (ChE) inhibition in common carp (Cyprinus carpio)

    Gruber, S.J.; Munn, M.D.

    1998-01-01

    Cholinesterase (ChE) activity was used as a biomarker for assessing exposure of common carp (Cyprinus carpio) to organophosphate and carbamate insecticides from irrigated agricultural waters. Carp were collected from a lake (Royal Lake) that receives most of its water from irrigation return flows and from a reference lake (Billy Clapp Lake) outside of the irrigation system. Results indicated that the mean whole-brain ChE activity of carp from Royal Lake (3.47 μmol/min/g tissue) was 34.2% less than that of carp from Billy Clapp Lake (5.27 μmol/min/g tissue) (p = 0.003). The depressed ChE activity in brain tissue of Royal Lake carp was in response to ChE-inhibiting insecticides detected in water samples in the weeks prior to tissue sampling; the most frequently detected insecticides included chlorpyrifos, azinphos-methyl, carbaryl, and ethoprop. Neither sex nor size appears to be a covariable in the analysis; ChE activity was not correlated with fish length or weight in either lake and there was no significant difference in ChE activity between the two sexes within each lake. Although organophosphate and carbamate insecticides can break down rapidly in the environment, this study suggests that in agricultural regions where insecticides are applied for extended periods of the year, nontarget aquatic biota may be exposed to high levels of ChE-inhibiting insecticides for a period of several months.

  12. Novel 2-aminopyrimidine carbamates as potent and orally active inhibitors of Lck: synthesis, SAR, and in vivo antiinflammatory activity.

    Martin, Matthew W; Newcomb, John; Nunes, Joseph J; McGowan, David C; Armistead, David M; Boucher, Christina; Buchanan, John L; Buckner, William; Chai, Lilly; Elbaum, Daniel; Epstein, Linda F; Faust, Theodore; Flynn, Shaun; Gallant, Paul; Gore, Anu; Gu, Yan; Hsieh, Faye; Huang, Xin; Lee, Josie H; Metz, Daniela; Middleton, Scot; Mohn, Deanna; Morgenstern, Kurt; Morrison, Michael J; Novak, Perry M; Oliveira-dos-Santos, Antonio; Powers, David; Rose, Paul; Schneider, Stephen; Sell, Stephanie; Tudor, Yanyan; Turci, Susan M; Welcher, Andrew A; White, Ryan D; Zack, Debra; Zhao, Huilin; Zhu, Li; Zhu, Xiaotian; Ghiron, Chiara; Amouzegh, Patricia; Ermann, Monika; Jenkins, James; Johnston, David; Napier, Spencer; Power, Eoin

    2006-08-10

    The lymphocyte-specific kinase (Lck) is a cytoplasmic tyrosine kinase of the Src family expressed in T cells and NK cells. Genetic evidence in both mice and humans demonstrates that Lck kinase activity is critical for signaling mediated by the T cell receptor (TCR), which leads to normal T cell development and activation. A small molecule inhibitor of Lck is expected to be useful in the treatment of T cell-mediated autoimmune and inflammatory disorders and/or organ transplant rejection. In this paper, we describe the synthesis, structure-activity relationships, and pharmacological characterization of 2-aminopyrimidine carbamates, a new class of compounds with potent and selective inhibition of Lck. The most promising compound of this series, 2,6-dimethylphenyl 2-((3,5-bis(methyloxy)-4-((3-(4-methyl-1-piperazinyl)propyl)oxy)phenyl)amino)-4-pyrimidinyl(2,4-bis(methyloxy)phenyl)carbamate (43) exhibits good activity when evaluated in in vitro assays and in an in vivo model of T cell activation. PMID:16884310

  13. Determination of Carbamate and Organophosphorus Pesticides in Vegetable Samples and the Efficiency of Gamma-Radiation in Their Removal

    Muhammed Alamgir Zaman Chowdhury

    2014-01-01

    Full Text Available In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena (n=16, purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC, and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50% of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40–48%, 35–43%, and 30–45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85–90%, 80–91%, and 90–95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80–95% of some pesticides.

  14. Carbamate Pesticide-Induced Apoptosis in Human T Lymphocytes

    Qing Li

    2015-04-01

    Full Text Available We previously found that carbamate pesticides induced significant apoptosis in human natural killer cells. To investigate whether carbamate pesticides also induce apoptosis in human T lymphocytes, in the present study Jurkat human T cells were treated in vitro with thiram, maneb, carbaryl or ziram. Apoptosis was determined by FITC-Annexin-V/PI staining. To explore the mechanism of apoptosis, intracellular levels of active caspase 3 and mitochondrial cytochrome-c release were determined by flow cytometry. We found that thiram, ziram, maneb and carbaryl also induced apoptosis in a time- and dose-dependent manner in the human T cells. However, the strength of the apoptosis-inducing effect differed among the pesticides, with the: thiram > ziram > maneb > carbaryl. Moreover, thiram significantly increased the intracellular level of active caspase 3 and caspase inhibitors significantly inhibited apoptosis. Thiram also significantly caused mitochondrial cytochrome-c release. These findings indicate that carbamate pesticides can induce apoptosis in human T cells, and the apoptosis is mediated by the activation of caspases and the release of mitochondrial cytochrome-c.

  15. Immobilization of acetylcholinesterase via biocompatible interface of silk fibroin for detection of organophosphate and carbamate pesticides

    Xue Rui [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Kang Tianfang, E-mail: kangtf@yahoo.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Lu Liping; Cheng Shuiyuan [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

    2012-06-01

    An amperometric biosensor for the detection of organophosphate and carbamate pesticides was developed based on the immobilization of acetylcholinesterase (AChE) on regenerated silk fibroin (SF) matrix by non-covalent adsorption. SF and AChE were coated sequentially on the surface of the glassy carbon electrode (GCE) which was modified with multiwall carbon nanotube (MWNTs). The obtained biosensor was denoted as AChE-SF/MWNTs/GCE. The atomic force microscopy images showed that the SF matrix provided a more homogeneous interface for the AChE immobilization. The aggregation of immobilizing AChE was therefore avoided. The cyclic voltammogram of thiocholine at this biosensor exhibited a well defined oxidation peak at 0.667 V (vs. SCE). The inhibition rate of methyl parathion to the immobilized AChE was proportional to the logarithm of the concentration of methyl parathion over the range of the concentration of methyl parathion from 3.5 Multiplication-Sign 10{sup -6} to 2.0 Multiplication-Sign 10{sup -3} M with a detection limit of 5.0 Multiplication-Sign 10{sup -7} M. Similarly, the linearly response range of carbaryl was from 1.0 Multiplication-Sign 10{sup -7} to 3.0 Multiplication-Sign 10{sup -5} M with a detection limit of 6.0 Multiplication-Sign 10{sup -8} M. The experimental results indicate that AChE not only can be immobilized steadily on the SF matrix, but also the bioactivity of immobilizing AChE can be preserved effectively.

  16. Survey of ethyl carbamate in fermented foods sold in the United Kingdom in 2004.

    Hasnip, Sarah; Crews, Colin; Potter, Nicholas; Christy, Julie; Chan, Danny; Bondu, Thomas; Matthews, Wendy; Walters, Barry; Patel, Krishna

    2007-04-01

    Results are presented of a survey of fermented foods and beverages sold in the United Kingdom for levels of ethyl carbamate (urethane) carried out to expand the range of food types sold in the United Kingdom for which data regarding ethyl carbamate are available. Samples were analyzed by in-house validated methods, which included measurement uncertainty estimates. The samples comprised 75 fermented liquids (beers, wines, fortified wines, spirits, liqueurs, soy sauces, and vinegars) and 25 fermented solid foods (cheeses, yogurts, soybean products, sauerkraut, yeast extract, olives, and Christmas pudding). Ethyl carbamate was not detected in the beers or the cider. Wines contained between 11 and 24 microg/kg and sake between 81 and 164 microg/kg. Fortified wines contained ethyl carbamate at levels between 14 and 60 microg/kg. Only two of five liqueurs contained ethyl carbamate. Most soy sauces and vinegars did not contain ethyl carbamate. No ethyl carbamate was detected in cheeses, yogurts, olives, or soybean-based products. Single samples of sauerkraut, yeast extract, and Christmas pudding contained low levels (29, 41, and 20 microg/kg ethyl carbamate, respectively). PMID:17328558

  17. Mild and Site-Selective Allylation of Enol Carbamates with Allylic Carbonates under Rhodium Catalysis.

    Sharma, Satyasheel; Han, Sang Hoon; Oh, Yongguk; Mishra, Neeraj Kumar; Han, Sangil; Kwak, Jong Hwan; Lee, Seok-Yong; Jung, Young Hoon; Kim, In Su

    2016-03-18

    The rhodium(III)-catalyzed mild and site-selective C-H allylation of enol carbamates with 4-vinyl-1,3-dioxolan-2-one and allylic carbonates affords allylic alcohols and terminal allylated products, respectively. The assistance of the carbamoyl directing group provides a straightforward preparation of biologically and synthetically important allylated enol carbamates. PMID:26906724

  18. Palladium-Catalyzed Ortho-Arylation of Carbamate-Protected Estrogens.

    Bedford, Robin B; Brenner, Peter B; Durrant, Steven J; Gallagher, Timothy; Méndez-Gálvez, Carolina; Montgomery, Michelle

    2016-05-01

    The palladium-catalyzed ortho-arylation of diethyl carbamate-protected estrone and estriol with aryl iodides gives the 2-arylated analogues. Subsequent removal of the carbamate directing group furnishes 2-arylated estrone, estradiol, or estriol depending on the method used. PMID:27057762

  19. Subchronic Toxicity Study in Rats of Two New Ethyl-Carbamates with Ixodicidal Activity

    María Guadalupe Prado-Ochoa

    2014-01-01

    Full Text Available Female and male Wistar rats were used to determine the subchronic oral toxicities of two new ethyl-carbamates with ixodicidal activities (ethyl-4-bromphenyl-carbamate and ethyl-4-chlorphenyl-carbamate. The evaluated carbamates were administered in the drinking water (12.5, 25 and 50 mg/kg/day for 90 days. Exposure to the evaluated carbamates did not cause mortality or clinical signs and did not affect food consumption or weight gain. However, exposure to these carbamates produced alterations in water consumption, hematocrit, percentages of reticulocytes, plasma proteins, some biochemical parameters (aspartate aminotransferase, gamma-glutamyl transpeptidase, cholinesterase, and creatinine activities, thiobarbituric acid reactive substances, and the relative weight of the spleen. Histologically, slight pathological alterations were found in the liver that were consistent with the observed biochemical alterations. The nonobserved adverse effect levels (NOAELs of the evaluated carbamates were 12.5 mg/kg/day for both the female and male rats. The low severity and reversibility of the majority of the observed alterations suggest that the evaluated carbamates have low subchronic toxicity.

  20. Facile one-pot synthesis of unsymmetrical ureas, carbamates, and thiocarbamates from Cbz-protected amines.

    Kim, Hee-Kwon; Lee, Anna

    2016-07-26

    A novel one-pot synthesis of unsymmetrical ureas, carbamates and thiocarbamates from Cbz-protected amines has been developed. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, isocyanates are generated in situ, which facilitate rapid reaction with amines, alcohols, and thiols to afford the corresponding ureas, carbamates and thiocarbamates in high yields. PMID:27406041

  1. 40 CFR 180.212 - S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues.

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. 180.212 Section 180.212 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Tolerances § 180.212 S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. (a) General....

  2. Synthesis and decreasing Aβ content evaluation of arctigenin-4-yl carbamate derivatives.

    Xu, Xingyu; Li, Cong; Lei, Min; Zhu, Zhiyuan; Yan, Jianming; Shen, Xu; Hu, Lihong

    2016-07-01

    A series of arctigenin-4-yl carbamate derivatives were synthesized and evaluated for potency in reducing β-amyloid (Aβ) content in HEK293-APPswe cells. Most of the arctigenin-4-yl aralkyl or aryl carbamate derivatives showed improved potency in reducing Aβ content. Among the synthesized compounds, arctigenin-4-yl (3-chlorophenyl)carbamate (20) exhibited the strongest potency with 78.7% Aβ content reduction at 20μM. Furthermore, the effect of arctigenin-4-yl (4-chlorophenyl)carbamate (19) and arctigenin-4-yl (3-chlorophenyl)carbamate (20) on lowing Aβ content was better than arctigenin under the concentrations of 1, 10 and 20μM. PMID:27212069

  3. Evaluation of carbamate insecticides as chemotherapeutic agents for cancer

    Mohd. Amanullah

    2011-01-01

    Full Text Available Background: Cancer chemotherapy has already been in practice by the use of toxins and some of the specific poisonous compounds of cyanide derivatives. Carbamate insecticides inhibit cellular metabolism including energy, protein, and nucleic acid metabolism, thereby, causing cell regression and death. Aim: Preliminary evaluation of three carbamate insecticides, namely, baygon, carbaryl, and carbofuran as chemotherapeutic agents for cancer is undertaken in the present study. Materials and Methods: The toxicity of carbamates on squamous cell carcinoma was assessed in-vitro using dye binding tests. Cells were grown in microtitration ELISA plates, as adherent cultures, for six hours, and then exposed to the drugs for 2, 4, 8, and 12 hours, and finally stained with neutral red, to assess the viable cell number, and with methylene blue for the determination of protein in the monolayer. Optical density was read in an ELISA reader. Statistical Analysis: The data obtained during the experiment was subjected to statistical analysis by using the student ′t′ test. Results: The results indicated that the percentage of the viable cell number reduced with an increase in the time of exposure of the drugs. Exposure of the tumor cells to the drugs for 12 hours detached them completely from the wells, and hence, all the cells were washed out. Exposure of the drugs prior to the establishment of the culture in-vitro resulted in the non-formation of the monolayer in the wells. Conclusions: Among the three drugs studied, the survival percent was least with carbaryl treatment followed by baygon, and with carbofuran treatment it was almost near to control group.

  4. Piezoelectric Biosensors for Organophosphate and Carbamate Pesticides: A Review

    Giovanna Marrazza

    2014-09-01

    Full Text Available Due to the great amount of pesticides currently being used, there is an increased interest for developing biosensors for their detection. Among all the physical transducers, piezoelectric systems have emerged as the most attractive due to their simplicity, low instrumentation costs, possibility for real-time and label-free detection and generally high sensitivity. This paper presents an overview of biosensors based on the quartz crystal microbalance, which have been reported in the literature for organophosphate and carbamate pesticide analysis.

  5. Inhibition Mechanism of Cholinesterases by Carbamate: A Theoretical Study

    YAO Yuan; LI Ze-sheng

    2008-01-01

    The density functional theory at the B3LYP/6-311G(d,p) level was applied to exploring the inhibition mechanism of cholinesterases by carbamate.The results indicate that the inhibition reactions with or without the catalytic effect of the catalytic triad in cholinesterases underwent a two-step addition-elimination mechanism,which is in good agreement with the proposed mechanism.The solvent has a strong effect on the inhibition reactions and the reaction with the catalytic triad in the solvent phase is close to the real reaction under biological condition.

  6. DNA Methylation

    İzmirli, Müzeyyen; Tufan, Turan; Alptekin, Davut

    2012-01-01

    Methylation is a chemical reaction in biological systems for normal genome regulation and development. It is a well known type of epigenetic mechanism. Methylation which regulates gene expression via epigenetic events like gene activation, repression, and chromatin remodelling, consists of two methylation systems. One of these systems is DNA methylation whereas the other is protein (histone) methylation. These systems are associated with some fundamental abnormalities and diseases. This revi...

  7. DNA Methylation

    Muzeyyen Izmirli; Turan Tufan; Davut Alptekin

    2012-01-01

    Methylation is a chemical reaction in biological systems for normal genome regulation and development. It is a well known type of epigenetic mechanism. Methylation which regulates gene expression via epigenetic events like gene activation, repression, and chromatin remodelling, consists of two methylation systems. One of these systems is DNA methylation whereas the other is protein (histone) methylation. These systems are associated with some fundamental abnormalities and diseases. This revie...

  8. tert-Butyl N-benzyl-N-[4-(4-fluorobenzoylmethyl-2-pyridyl]carbamate

    Pierre Koch

    2008-11-01

    Full Text Available In the crystal structure of the title compound, C25H25FN2O3, the pyridine ring makes dihedral angles of 75.1 (3, 39.4 (3 and 74.6 (3° with the phenyl ring, the carbamate plane and the 4-fluorophenyl ring, respectively. The phenyl ring makes dihedral angles of 77.2 (3 and 23.6 (3° with the carbamate plane and the 4-fluorophenyl ring, respectively. The 4-fluorophenyl ring is perpendicular to the carbamate plane, the dihedral angle between them being 89.5 (3°.

  9. Cumulative risk assessment of the intake of organophosphorus and carbamate pesticides in the Danish diet

    Jensen, A. F.; Petersen, Annette; Granby, Kit

    2003-01-01

    in the Danish nation-wide food consumption survey in 1995. The pesticide data are based on the Danish pesticide residue-monitoring programme from 1996-2001. The amount of 35 organophosphorus pesticides and carbamates were included in the cumulative risk assessment. Processing factors, such as reduction......The aim of the study is to evaluate the potential cumulative effects of organophosphorus and carbamate pesticides that act through a common mechanism of toxicity, and to assess the long- and short-term risks for the Danish population. The intake estimates are based on dietary intake data collected...... of pesticide levels by rinsing and peeling, were applied in the exposure assessment. The "Toxicity Equivalence Factor" (TEF) approach was used to normalise the toxicity of the different organophosphorus and carbamate pesticides. Cumulative chronic exposure of organophosphorus and carbamates pesticides via...

  10. The thermal desorption of CO2 from amine carbamate solutions for the 13C isotope enrichment

    Dronca, S.; Varodi, C.; Gligan, M.; Stoia, V.; Baldea, A.; Hodor, I.

    2012-02-01

    The CO2 desorption from amine carbamate in non-aqueous solvents is of major importance for isotopic enrichment of 13C. A series of experiments were carried out in order to set up the conditions for the CO2 desorption. For this purpose, a laboratory- scale plant for 13C isotope separation by chemical exchange between CO2 and amine carbamate was designed and used. The decomposition of the carbamate solution was mostly produced in the desorber and completed in the boiler. Two different-length desorbers were used, at different temperatures and liquid flow rates of the amine-non-aqueous solvent solutions. The residual CO2 was determined by using volumetric and gaschromatographic methods. These results can be used for enrichment of 13C by chemical exchange between CO2 and amine carbamate in nonaqueous solvents.

  11. Carbamates toxicity in farmers and its assesment through biochemical parameters

    Prevalent environmental toxicity of various chemical group of pesticides and their effects leading towards increasing morbidity and mortality in the farmers is of great concerned. In this situation the biochemical biomarkers are regarded as meaningful tools for monitoring toxic end points. This work was aimed to assess the toxic impacts of carbamates through some biochemical parameters and useful validity of these biomarkers was also observed. Present results reveal inhibition of cholinesterase activity by 46% whereas bilirubin, urea and creatinine levels in serum were increased and sugar values was decreased at highly significant level (p<0.001). Urine urobilinogen concentration found raised significantly at high level (p<0.001) while protein, urea creatinine and sugar values in urine of the farmers seen non-significant. This study concluded that the selected biochemical parameters can be used as biomarkers to assess the significant toxic effects in the exposed populations. (author)

  12. Potent Urea and Carbamate Inhibitors of Soluble Epoxide Hydrolases

    Morisseau, Christophe; Goodrow, Marvin H.; Dowdy, Deanna; Zheng, Jiang; Greene, Jessica F.; Sanborn, James R.; Hammock, Bruce D.

    1999-08-01

    The soluble epoxide hydrolase (sEH) plays a significant role in the biosynthesis of inflammation mediators as well as xenobiotic transformations. Herein, we report the discovery of substituted ureas and carbamates as potent inhibitors of sEH. Some of these selective, competitive tightbinding inhibitors with nanomolar Ki values interacted stoichiometrically with the homogenous recombinant murine and human sEHs. These inhibitors enhance cytotoxicity of trans-stilbene oxide, which is active as the epoxide, but reduce cytotoxicity of leukotoxin, which is activated by epoxide hydrolase to its toxic diol. They also reduce toxicity of leukotoxin in vivo in mice and prevent symptoms suggestive of acute respiratory distress syndrome. These potent inhibitors may be valuable tools for testing hypotheses of involvement of diol and epoxide lipids in chemical mediation in vitro or in vivo systems.

  13. Ethyl carbamate levels in selected fermented foods and beverages.

    Canas, B J; Havery, D C; Robinson, L R; Sullivan, M P; Joe, F L; Diachenko, G W

    1989-01-01

    Ethyl carbamate (EC), also known as urethane, is an animal carcinogen and a by-product of fermentation. Because EC has been found in distilled spirits and wines, a variety of fermented foods and beverages were analyzed to assess its occurrence in other products. Previously described methods using a gas chromatograph-thermal energy analyzer with a nitrogen converter were modified for each matrix and gave recoveries of greater than 80%, with a limit of detection in the 1-2 micrograms/kg (ppb) range. A total of 152 test samples were analyzed; EC levels ranged from none found to 3 ppb in 15 cheeses, 6 teas, 12 yogurts, and 8 ciders; from none found to 13 ppb in 30 breads and 69 malt beverages; and from none found to 84 ppb in 12 soy sauces. Gas chromatography/mass spectrometry/mass spectrometry was used to confirm EC identity and to quantitate EC in selected food extracts. PMID:2592308

  14. Novel aryl carbamate derivatives of metronidazole as potential antiamoebic agents.

    Hayat, Faisal; Wahedi, Hussain Mustatab; Park, Seonghyeok; Tariq, Saba; Azam, Amir; Shin, Dongyun

    2016-01-01

    A series of novel aryl carbamate derivatives of metronidazole (MNZ) were designed, synthesized, and screened for antiamoebic activity. As compared to MNZ, most of the derivatives exhibited moderate to excellent activity against the HM1:IMSS strain of Entamoeba histolytica. Compounds 7, 14, 16, 19, and 21 exhibited the most promising antiamoebic activity with IC50 values of 0.24, 0.08, 0.26, 0.26, and 0.15 μM, respectively, compared to that of MNZ (1.78 μM). Moreover, from the toxicological studies of these compounds on human melanocytes, the melan-a cell line revealed that the potent compounds are nontoxic at concentrations ranging from 2.5 to 50 μM. PMID:26597858

  15. Semi disposable reactor biosensors for detecting carbamate pesticides in water.

    Suwansa-ard, Siriwan; Kanatharana, Proespichaya; Asawatreratanakul, Punnee; Limsakul, Chusak; Wongkittisuksa, Booncharoen; Thavarungkul, Panote

    2005-09-15

    Two flow-injection biosensor systems using semi disposable enzyme reactor have been developed to determine carbamate pesticides in water samples. Acetylcholinesterase was immobilized on silica gel by covalent binding. pH and conductivity electrodes were used to detect the ionic change of the sample solution due to hydrolysis of acetylcholine. Carbamate pesticides inhibited acetylcholinesterase and the decrease in the enzyme activity was used to determine these pesticides. Parameters influencing the performance of the systems were optimized to be used in the inhibition procedure. Carbofuran and carbaryl were used to test these systems. Detection limits for the potentiometric and conductimetric systems were both at 10% inhibition corresponding to 0.02 and 0.3 ppm of carbofuran and carbaryl, respectively. Both systems also provided the same linear ranges, 0.02-8.0 ppm for carbofuran, and 0.3-10 ppm for carbaryl. The analysis of pesticides was done a few times before the reactor was disposed. Percentages of inhibition obtained from different reactors were reproducible, therefore, no recalibration was necessary when changing the reactor. The biosensors were used to analyze carbaryl in water samples from six wells in a vegetable growing area. Both systems could detect the presence of carbaryl in the samples and provided good recoveries of the added carbaryl, i.e., 80-106% for the potentiometric system and 75-105% for the conductimetric system. The presence of carbaryl in water samples analyzed by the biosensors was confirmed by gas chromatography-mass spectrometric system. These biosensors do not require any sample preconcentration and are suitable for detecting pesticides in real water samples. PMID:16076434

  16. Selective effects of carbamate pesticides on rat neuronal nicotinic acetylcholine receptors and rat brain acetylcholinesterase

    Effects of commonly used carbamate pesticides on rat neuronal nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes have been investigated using the two-electrode voltage clamp technique. The potencies of these effects have been compared to the potencies of the carbamates to inhibit rat brain acetylcholinesterase. The potency order of six carbamates to inhibit α4β4 nicotinic receptors is fenoxycarb > EPTC > carbaryl, bendiocarb > propoxur > aldicarb with IC50 values ranging from 3 μM for fenoxycarb to 165 μM for propoxur and >1 mM for aldicarb. Conversely, the potency order of these carbamates to inhibit rat brain acetylcholinesterase is bendiocarb > propoxur, aldicarb > carbaryl >> EPTC, fenoxycarb with IC50 values ranging from 1 μM for bendiocarb to 17 μM for carbaryl and >>1 mM for EPTC and fenoxycarb. The α4β2, α3β4, and α3β2 nicotinic acetylcholine receptors are inhibited by fenoxycarb, EPTC, and carbaryl with potency orders similar to that for α4β4 receptors. Comparing the potencies of inhibition of the distinct subtypes of nicotinic acetylcholine receptors shows that the α3β2 receptor is less sensitive to inhibition by fenoxycarb and EPTC. The potency of inhibition depends on the carbamate as well as on a combination of α and β subunit properties. It is concluded that carbamate pesticides affect different subtypes of neuronal nicotinic receptors independently of acetylcholinesterase inhibition. This implicates that neuronal nicotinic receptors are additional targets for some carbamate pesticides and that these receptors may contribute to carbamate pesticide toxicology, especially after long-term exposure

  17. Age-related differences in neurotoxicity produced by organophosphorus and N-methyl carbamate pesticides

    Potential pesticide effects in infants and toddlers have received much attention in the scientific literature and the public media, including the concern for increased response to acute or shortterm exposures. Age-related differences in the acute neurotoxicity of acetylcholinest...

  18. Age-related differences in acetylcholinesterase inhibition produced by organophosphorus and N-methyl carbamate pesticides

    Introduction The concern that infants and children may be more susceptible to the toxic effects of chemicals, including pesticides, has received much attention in the scientific literature and the public media. Greater toxicity may be evident as long-term adverse outcomes, e.g.,...

  19. tert-Butyl N-{4-methyl-3-[4-(3-pyridylpyrimidin-2-yloxy]phenyl}carbamate

    Shi-Gui Tang

    2009-08-01

    Full Text Available In the molecule of the title compound, C21H22N4O3, the pyrimidine ring is oriented at dihedral angles of 0.51 (3 and 50.76 (3° to the pyridine and benzene rings, respectively. In the crystal structure, intermolecular N—H...N hydrogen bonds link the molecules into centrosymmetric dimers, forming R22(24 ring motifs; the dimers are linked by intermolecular C—H...O hydrogen bonds into a two-dimensional network. π–π contacts between the benzene rings and between the pyrimidine and pyridine rings [centroid–centroid distances = 3.891 (1 and 3.646 (1 Å, respectively] may further stabilize the structure. Two weak C—H...π interactions are also present.

  20. Methyl N-{4-[(4-methoxyphenoxymethyl]-2-oxo-2H-chromen-7-yl}carbamate

    K. Mahesh Kumar

    2012-06-01

    Full Text Available In the title compound, C19H17NO6, the dihedral angle between the 2H-chromene ring system and benzene ring is 5.34 (6°. A short intramolecular C—H...O contact occurs. In the crystal, molecules are linked by N—H...O hydrogen bonds, generating C(8 chains propagating in [010]. The chains are linked by C—H...O interactions and the packing also exhibits π–π stacking interactions between benzene and pyran rings, with a centroid–centroid distance of 3.676 (9 Å.

  1. Carbamate Toxicity and Protective effect of vit. A and vit. E on some biochemicalaspects of male albino rats

    Samir, A.M. Zaahkouk* ; Eman, G.E. Helal

    2000-12-01

    Full Text Available The effect of daily oral administration of carbamate (1/10 L.D50 on rats for 30 successive days were studied. The male rats were divided into five groups (control, control + oil, carbamate, carbamate + vit. A and carbamate + vit. E. Each group (except control and control + oil was daily administrated carbamate (0.012 mg/kg B.wt.. Two groups of carbamate ­ intoxicated animals provided with vit. A (700 mg/kg.B.wt or vit. E (10 mg/kg.B.wt. Poisoning symptoms were recorded, e.g. unbalanse, diarrhea, have poor health and posterior limbs rigidity. Haematological parameters showed a significant decrease in red blood corpuscles (R.B.Cs, white blood corpuscles (W.B.Cs count, Haemoglobin concentration and haematocrit value in groups treated with carbamate, and an improvement in these values was observed in groups treated with the anti-oxidants (vit. A and vit. E. Total lipids cholesterol, total proteins, albumin, glucose, LDH, AST, ALT, adrenaline and noradrenaline were measured in serum. Total proteins, total lipids, of tissues (liver, heart, muscle and kidney were investigated. The present study declare that, carbamate induced a significant elevetion in serum LDH, glucose. total lipids,cholesterol, AST, ALT, adrenaline and noradrenaline. On the other hand, causes a significant reduction in total proteins and albumin. The total lipids and total proteins of the tissue were recorded highly significant decrease in the group treated with carbamate only. From another point of view, antioxidant ameliorated the effect of carbamate on tissues. So, it is clear that administration of vit. E or vit. A. reduced the effect of carbamate on biochemical alteration to various extent. The antioxidant property of vitamin A and vitamin E seem to be responsible for the observed protection against carbamate intoxication.

  2. Distribution of ace-1R and resistance to carbamates and organophosphates in Anopheles gambiae s.s. populations from Côte d'Ivoire

    Ahoua Alou Ludovic P

    2010-06-01

    Full Text Available Abstract Background The spread of pyrethroid resistance in Anopheles gambiae s.s. is a critical issue for malaria vector control based on the use of insecticide-treated nets. Carbamates and organophosphates insecticides are regarded as alternatives or supplements to pyrethroids used in nets treatment. It is, therefore, essential to investigate on the susceptibility of pyrethroid resistant populations of An. gambiae s.s. to these alternative products. Methods In September 2004, a cross sectional survey was conducted in six localities in Côte d'Ivoire: Toumbokro, Yamoussoukro, Toumodi in the Southern Guinea savannah, Tiassalé in semi-deciduous forest, then Nieky and Abidjan in evergreen forest area. An. gambiae populations from these localities were previously reported to be highly resistant to pyrethroids insecticides. Anopheline larvae were collected from the field and reared to adults. Resistance/susceptibility to carbamates (0.4% carbosulfan, 0.1% propoxur and organophosphates (0.4% chlorpyrifos-methyl, 1% fenitrothion was assessed using WHO bioassay test kits for adult mosquitoes. Then, PCR assays were run to determine the molecular forms (M and (S, as well as phenotypes for insensitive acetylcholinesterase (AChE1 due to G119S mutation. Results Bioassays showed carbamates (carbosulfan and propoxur resistance in all tested populations of An. gambiae s.s. In addition, two out of the six tested populations (Toumodi and Tiassalé were also resistant to organophosphates (mortality rates ranged from 29.5% to 93.3%. The M-form was predominant in tested samples (91.8%. M and S molecular forms were sympatric at two localities but no M/S hybrids were detected. The highest proportion of S-form (7.9% of An. gambiae identified was in sample from Toumbokro, in the southern Guinea savannah. The G119S mutation was found in both M and S molecular forms with frequency from 30.9 to 35.2%. Conclusion This study revealed a wide distribution of insensitive

  3. Methyl Iodide

    Methyl iodide (MeI, iodomethane, CH3I) was reported as a potential alternative to the stratospheric ozone-depleting fumigant methyl bromide (MeBr) in the mid-1990s (Sims et al., 1995; Ohr et al., 1996). It has since received significant research attention to determine its environmental fate and tran...

  4. Lignin is linked to ethyl-carbamate formation in ume (Prunus mume) liqueur.

    Hashiguchi, Tomokazu; Izu, Hanae; Sudo, Shigetoshi

    2012-01-01

    Ethyl carbamate concentrations in oak barrel-aged ume (Prunus mume) liqueurs were measured, and possible explanations for elevated levels were examined. The average concentration was 0.30 mg/L, significantly higher than in ume liqueurs not aged in oak (0.08 mg/L). Oak powder extracts were prepared from both untoasted and toasted oak powder by extraction with aqueous ethanol, and these were used to make ume liqueurs. Relative to a no-oak control, the ethyl carbamate concentrations were 3.8 and 11 times higher in the ume liqueur made with the untoasted and toasted oak powder extracts respectively. The extracts were loaded onto a C18 column, washed with water, and eluted with methanol. The (13)C-NMR spectra for the main constituents of the methanol elution fractions were consistent with those for lignin or fragments thereof. The methanol fractions were added to ume liqueur which was stored for 3 months. Relative to a control, the ethyl carbamate concentrations in the 3-month old liqueurs were found to be 1.2 and 4.6 higher for the untoasted oak-powder and the toasted oak-powder respectively. Ethyl carbamate was formed when lignin was added to a 40% aqueous ethanol solution that contained potassium cyanide. These observations suggest that lignin or fragments thereof promote the formation of ethyl carbamate. PMID:22232267

  5. Copper(II) catalysis in cyanide conversion into ethyl carbamate in spirits and relevant reactions.

    Aresta, M; Boscolo, M; Franco, D W

    2001-06-01

    The role of copper(II) species in the oxidation of inorganic cyanide to cyanate and in the conversion of cyanate or urea into ethyl carbamate was investigated. The oxidation process has been shown to be independent from the dissolved oxygen. Elemental analysis and infrared spectroscopy have shown the formation of a mixed copper carbonate/hydroxide in the process of oxidation of cyanide to cyanate in water/ethanol. The complexation to Cu(II) of cyanate formed upon cyanide oxidation makes the former more susceptible to nucleophilic attack from ethanol, with conversion into ethyl carbamate. Comparatively, urea has a minor role with respect to cyanide in the formation of ethyl carbamate. Therefore, the urea present in some samples of Brazilian sugar cane spirit (cachaça) has been shown to have almost no influence on the ethyl carbamate content of cachaças, which comes essentially from cyanide. Fe(II,III) affords results similar to those found with Cu(II). Some suggestions are presented to avoid ethyl carbamate formation in spirits during distillation. PMID:11409971

  6. New synthesis of carbamate, thiocarbamate and urea type herbicides: preparation of 14C-labelled diuron and EPTC

    N,N-dialkyl-carbamic acid-trimethylsilyl-esters were synthesized starting with 14CO2. The new synthesis route is simple and provides good radiochemical yield. Silyl-carbaminates directly or through carbamoyl-halogenides may be used for preparation of labelled herbicides: carbamates, thiocarbamates and ureas. (author)

  7. Assessment of Acute Oral and Dermal Toxicity of 2 Ethyl-Carbamates with Activity against Rhipicephalus microplus in Rats

    María Guadalupe Prado-Ochoa

    2014-01-01

    Full Text Available The acute oral and dermal toxicity of two new ethyl-carbamates (ethyl-4-bromophenyl-carbamate and ethyl-4-chlorophenyl-carbamate with ixodicide activity was determined in rats. The oral LD50 of each carbamate was 300 to 2000 mg/kg, and the dermal LD50 of each carbamate was >5000 mg/kg. Clinically, the surviving rats that had received oral doses of each carbamate showed decreased weight gain (P<0.05 and had slight nervous system manifestations. These clinical signs were evident from the 300 mg/kg dose and were reversible, whereas the 2000 mg/kg dose caused severe damage and either caused their death or was motive for euthanasia. At necropsy, these rats had dilated stomachs and cecums with diffuse congestion, as well as moderate congestion of the liver. Histologically, the liver showed slight degenerative lesions, binucleated hepatocytes, focal coagulative necrosis, and congestion areas; the severity of the lesions increased with dosage. Furthermore, an slight increase in gamma-glutamyltransferase, lactate dehydrogenase, and creatinine was observed in the plasma. The dermal application of the maximum dose (5000 mg/kg of each carbamate did not cause clinical manifestations or liver and skin alterations. This finding demonstrates that the carbamates under study have a low oral hazard and low acute dermal toxicity.

  8. DNA Methylation

    Alokail, Majed S.; Alenad, Amal M

    2015-01-01

    The DNA of E. coli contains 19,120 6-methyladenines and 12,045 5-methylcytosines in addition to the four regular bases and these are formed by the postreplicative action of three DNA methyltransferases. The majority of the methylated bases are formed by the Dam and Dcm methyltransferases encoded by the dam (DNA adenine methyltransferase) and dcm (DNA cytosine methyltransferase) genes. Although not essential, Dam methylation is important for strand discrimination during repair of replication e...

  9. Gas chromatographic-mass spectrometric determination of ethyl carbamate in alcoholic beverages.

    Lau, B P; Weber, D; Page, B D

    1987-07-31

    A sensitive and specific method based on gas chromatography-mass spectrometry for the quantitative determination of ethyl carbamate in table wines, fortified wines (such as ports and sherries), distilled spirits, brandies and liqueurs has been developed. Three characteristic ions from ethyl carbamate [m/z 89 (molecular ion), 74 and 62] were monitored in the selected-ion monitoring (SIM) mode. The lowest detection limit (based on the response on the m/z 62 ion) was estimated to be 0.5 ng/g (ppb). Additional confirmation techniques, including high-resolution SIM, and methane or isobutane chemical ionization are described. PMID:3654867

  10. The carcinogenic potential of ethyl carbamate (urethane): risk assessment at human dietary exposure levels

    Schlatter, J; Werner K Lutz

    2012-01-01

    Ethyl carbamate is found in fermented foods: bread contains 3-15 ng/g, stone-fruit brandies 200-20,000 ngfg, and about one-third of table-wine samples analysed contained more than 10 ng/g. In animals, ethyl carbamate is degraded to C02, H20 and NH3, with intermediate formation ofethanol. This degradation has been shown tobe inhibited (postponed) in the mouse by ethanol concentrations in the blood of about 0.15% and higher. A quantitatively minor pathway involves a two-step oxidation of the et...

  11. Application of brain cholinesterase reactivation to differentiate between organophosphorus and carbamate pesticide exposure in wild birds

    Smith, M.R.; Thomas, N.J.; Hulse, C.

    1995-01-01

    Brain cholinesterase activity was measured to evaluate pesticide exposure in wild birds. Thermal reactivation of brain cholinesterase was used to differentiate between carbamate and organophosphorus pesticide exposure. Brain cholinesterase activity was compared with gas chromatography and mass spectrometry of stomach contents. Pesticides were identified and confirmed in 86 of 102 incidents of mortality from 29 states within the USA from 1986 through 1991. Thermal reactivation of cholinesterase activity was used to correctly predict carbamates in 22 incidents and organophosphates in 59 incidents. Agreement (P < 0.001) between predictions based on cholinesterase activities and GC/MS results was significant.

  12. DNA methylation

    Williams, Kristine; Christensen, Jesper; Helin, Kristian

    2012-01-01

    DNA methylation is involved in key cellular processes, including X-chromosome inactivation, imprinting and transcriptional silencing of specific genes and repetitive elements. DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. The recent...... discovery that the three members of the TET protein family can convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) has provided a potential mechanism leading to DNA demethylation. Moreover, the demonstration that TET2 is frequently mutated in haematopoietic tumours suggests that the TET...... proteins are important regulators of cellular identity. Here, we review the current knowledge regarding the function of the TET proteins, and discuss various mechanisms by which they contribute to transcriptional control. We propose that the TET proteins have an important role in regulating DNA methylation...

  13. Investigation of ethyl carbamate levels in some fermented foods and alcoholic beverages.

    Dennis, M J; Howarth, N; Key, P E; Pointer, M; Massey, R C

    1989-01-01

    An analytical procedure has been developed for the determination of trace amounts of ethyl carbamate in fermented foodstuffs and alcoholic beverages. Concentrations were generally below the 1-5 micrograms/kg detection limit in bread, cheese, yoghurt, beer, gin and vodka. Higher concentrations were found in the other alcoholic beverages examined, which included whisky, fruit brandy, liqueur, wine, sherry and port. PMID:2721787

  14. Detection of benzimidazole carbamates and amino metabolites in liver by surface plasmon resonance-biosensor

    Two surface plasmon resonance (SPR) biosensor screening assays were developed and validated to detect 11 benzimidazole carbamate (BZT) and four amino-benzimidazole veterinary drug residues in liver tissue. The assays used polyclonal antibodies, raised in sheep, to detect BZTs and amino-benzimidazole...

  15. Photochemical decomposition of carbamate pesticides in natural waters of northern Greece

    The photochemical decomposition of the carbamate pesticides carbofuran, carbaryl and thiram was examined in natural waters of northern Greece under the influence of solar and UV (λ > 290 nm) radiation. Different major photoproducts were detected by GC/MS. The result of continuous irradiation was almost total degradation of the pesticides examined

  16. Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

    Lipp, Alexander; Lahm, Günther; Opatz, Till

    2016-06-01

    A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature. PMID:27128627

  17. Fenugreek hydrogel–agarose composite entrapped gold nanoparticles for acetylcholinesterase based biosensor for carbamates detection

    A biosensor was fabricated to detect pesticides in food samples. Acetylcholinesterase was immobilized in a novel fenugreek hydrogel–agarose matrix with gold nanoparticles. Transparent thin films with superior mechanical strength and stability were obtained with 2% fenugreek hydrogel and 2% agarose. Immobilization of acetylcholinesterase on the membrane resulted in high enzyme retention efficiency (92%) and a significantly prolonged shelf life of the enzyme (half-life, 55 days). Transmission electron microscopy revealed that, gold nanoparticles (10–20 nm in diameter) were uniformly dispersed in the fenugreek hydrogel–agarose–acetylcholinesterase membrane. This immobilized enzyme-gold nanoparticle dip-strip system detected various carbamates, including carbofuran, oxamyl, methomyl, and carbaryl, with limits of detection of 2, 21, 113, and 236 nM (S/N = 3), respectively. Furthermore, the fabricated biosensor exhibited good testing capabilities when used to detect carbamates added to various fruit and vegetable samples. - Highlights: • Acetylcholinesterase (AChE) dip-strip biosensor fabricated to detect carbamates. • AChE entrapped in fenugreek hydrogel–agarose matrix with gold nanoparticles (GNPs). • High enzyme retention efficiency (92%) and shelf life (half-life, 55 days). • Detection limits of carbofuran, oxamyl and methomyl: 2, 21 and 113 nM. • The biosensor had good testing capabilities to detect carbamates in food samples

  18. Fenugreek hydrogel–agarose composite entrapped gold nanoparticles for acetylcholinesterase based biosensor for carbamates detection

    Kestwal, Rakesh Mohan; Bagal-Kestwal, Dipali; Chiang, Been-Huang, E-mail: bhchiang@ntu.edu.tw

    2015-07-30

    A biosensor was fabricated to detect pesticides in food samples. Acetylcholinesterase was immobilized in a novel fenugreek hydrogel–agarose matrix with gold nanoparticles. Transparent thin films with superior mechanical strength and stability were obtained with 2% fenugreek hydrogel and 2% agarose. Immobilization of acetylcholinesterase on the membrane resulted in high enzyme retention efficiency (92%) and a significantly prolonged shelf life of the enzyme (half-life, 55 days). Transmission electron microscopy revealed that, gold nanoparticles (10–20 nm in diameter) were uniformly dispersed in the fenugreek hydrogel–agarose–acetylcholinesterase membrane. This immobilized enzyme-gold nanoparticle dip-strip system detected various carbamates, including carbofuran, oxamyl, methomyl, and carbaryl, with limits of detection of 2, 21, 113, and 236 nM (S/N = 3), respectively. Furthermore, the fabricated biosensor exhibited good testing capabilities when used to detect carbamates added to various fruit and vegetable samples. - Highlights: • Acetylcholinesterase (AChE) dip-strip biosensor fabricated to detect carbamates. • AChE entrapped in fenugreek hydrogel–agarose matrix with gold nanoparticles (GNPs). • High enzyme retention efficiency (92%) and shelf life (half-life, 55 days). • Detection limits of carbofuran, oxamyl and methomyl: 2, 21 and 113 nM. • The biosensor had good testing capabilities to detect carbamates in food samples.

  19. Acetylcholinesterase inhibition as an indicator of organophosphate and carbamate poisoning in Kenyan agricultural workers.

    Ohayo-Mitoko, G.J.A.; Heederik, D.; Kromhout, H.; Omondi, B.E.O.; Boleij, J.S.M.

    1997-01-01

    Acetylcholinesterase inhibition was determined for 666 Kenyan agricultural workers; 390 (58.6%) mainly pesticide applicators exposed to organophosphate and carbamate pesticides and 276 (41.4%) unexposed controls from four rural agricultural areas during 1993 and 1994. Baseline levels were depressed

  20. BETA-GLUCURONYL CARBAMATE BASED PRO-MOIETIES DESIGNED FOR PRODRUGS IN ADEPT

    LEENDERS, RGG; GERRITS, KAA; RUIJTENBEEK, R; SCHEEREN, HW; Haisma, Hidde; BOVEN, E

    1995-01-01

    A number of pro-moieties 8a - e designed for prodrug preparation have been synthesized (chart 2). The pro-moieties, containing a glucuronyl carbamate group linked to a spacer possessing a terminal carboxylic acid group, have been synthesized from isocyanates 6 and anomerically unprotected glucuronic

  1. Evaluation of ethyl N-(2-phenethyl) carbamate analogues as biofilm inhibitors of methicillin resistant Staphylococcus aureus.

    Stephens, Matthew D; Yodsanit, Nisakorn; Melander, Christian

    2016-07-12

    A small molecule library consisting of 45 compounds was synthesized based on the bacterial metabolite ethyl N-(2-phenethyl) carbamate. Screening of the compounds revealed a potent analogue capabale of inhibiting several strains of Methicillin Resistant S. aureus biofilms with low to moderate micromolar IC50 values. PMID:27341658

  2. Carbamate Stabilities of Sterically Hindered Amines from Quantum Chemical Methods: Relevance ofr CO2 Capture

    Gangarapu, S.; Marcelis, A.T.M.; Zuilhof, H.

    2013-01-01

    The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled

  3. Synthesis and Bioevaluation of 3-(substitutedphenyl-1-(4-hydroxyphenyl-2-propen-1-ones and their Carbamate Derivatives against Root – Knot Nematode (Meloidogyne javanica

    Sumona Kumari

    2014-09-01

    Full Text Available Synthesis of 3-(4-chloro/methyl/nitro/methoxy/3,4,5-trimethoxy/2,4-dichloro/ 4-bromo/ 3, 4-dimethoxy/ 2, 4-dimethoxy/ 3-bromo/ 2-chloro/ 2-methoxy phenyl-1-(4-hydroxyphenyl-2-propen-1-one (14-25 has been carried out from substituted benzaldehyde (1-12 and 4-hydroxy acetophenone (13. The condensation of synthesized 2-propen-1-ones (14-25 with phenyl isocyanate (26 gave 4-[3-(4-chloro/ methyl/nitro/methoxy/3, 4, 5-trimethoxy/2, 4-dichloro/4-bromo/3, 4-dimethoxy/2, 4-dimethoxy/3-bromo phenyl prop-2-enoyl] phenyl phenylcarbamate (27-36. The synthesized compounds were characterized on the basis of analytical and spectral data. All the compounds were evaluated for their nematicidal activity in- vitro against second stage juveniles (J2 of root - knot nematode (Meloidogyne javanica. Incorporation of carbamoyloxy moiety in 2-propen-1-ones enhanced the activity. Irrespective of the concentration, compounds 3-(4-methoxyphenyl-1-(4-hydroxyphenyl-2-propen-1-one (17 and 4-[3-(4-methoxyphenyl prop-2-enoyl] phenyl phenyl carbamate (30 have shown maximum nematode mortality i.e. 30% and 51.8%.

  4. RECOVERY OF URANIUM BY CYCLOALKYLDITHIO-CARBAMATE COMPLEXING

    Neville, O.K.

    1959-06-30

    The separation of uranium-233 from an aqueous nitric acid solution of neutron irradiated thorium by selectively complexing the uranium is described. The separation is carried out by contacting the thorium solution with a non- aromatic organic dithiocarbamate selected from the group which consists of alkali and alkaline earth cycloalkyldithiocarbamates and recovering the resulting uranyl cycloalkyldithiocarbamate complex by organic solvent extraction such as with methyl ethyl ketone. The complexed uranium may be stripped from the separated organic phase by scrubbing with one normal nitric acid solution.

  5. The concentration of ethyl carbamate in commercial ume (Prunus mume) liqueur products and a method of reducing it.

    Hashiguchi, Tomokazu; Horii, Sachie; Izu, Hanae; Sudo, Shigetoshi

    2010-01-01

    The ethyl carbamate concentration of commercial ume liqueur products was studied, and a method of reducing it was examined from the viewpoint of antioxidation. The average ethyl carbamate concentration across 38 ume liqueur products was 0.12 mg/l (0.02-0.33 mg/l). When potassium metabisulfite was added to a concentration of 0-1,000 ppm during production, the generation of ethyl carbamate was reduced in a concentration-dependent manner, but when the amount of potassium metabisulfite added was below the maximum level allowed under the Japanese Food Sanitation Act, the reduction was only 27%. When ume liqueurs were produced under deoxygenated conditions created using an oxygen absorber, the ethyl carbamate concentration was reduced by up to 47% as compared with the control group, probably due mainly to a reduction in free hydrogen cyanide. When ume liqueur was produced in an oxygen atmosphere, the ethyl carbamate concentration increased by up to 50% as compared with the control group. Thus, oxygen may be involved in the generation of ethyl carbamate in ume liqueur production. PMID:20944415

  6. Sulfonamide and carbamate derivatives of 6-chloropurine: synthesis, characterization and antimicrobial activity evaluation

    K. Venkata Narayana

    2016-07-01

    Full Text Available A series of new sulfonamide derivatives, 9-(substitutedbenzenesulfonyl-6-chloro-9H-purines 7(a-e and carbamate derivatives, 6-chloro-purine-9-carboxylic acid substituted alkyl/arylester 9(a-d, have been synthesized through an intermediate, sodium salt of 6-chloro-9(H-purine (6 which was prepared by the treatment of 6-chloro-9(H-purine (4 with sodium hydride. Structures of the newly synthesized compounds were elucidated by IR, NMR ( 1H and 13C, mass spectra and elemental analysis. Antimicrobial activity against three bacterial strains and three fungal strains at two different concentrations, 100 and 200 µg/mL including MIC values was investigated. Bio-screening data disclosed that most of the sulfonamide derivatives, 7a, 7c and 7d, and one carbamate derivative 9a showed promising antimicrobial activity having MIC values in the range of 18.0-25.0 µg/mL.

  7. Highly conductive polymer electrolyte membranes modified with polyethylene glycol-bis-carbamate

    Fu, Guopeng; Dempsey, Janel; Kyu, Thein

    By virtue of its non-flammability and chemical stability, polyethylene glycol (PEG) networks have shown potential application in all solid-state polymer electrolyte membranes (PEM). However, room temperature ionic conductivity of these PEG based PEMs is inherently low. Plasticization of these PEMs is needed to improve the ionic conductivity. It was demonstrated by this group that small-molecule plasticizers such as succinonitrile, ethylene carbonate, or urea-carbamate can boost ionic conductivity of solid-state polymer electrolyte membranes. Polyethylene glycol bis-carbamate (PEGBC) was synthesized via condensation reaction of polyethylene glycol diamine and ethylene carbonate. The PEGBC modified PEM has shown higher ionic conductivity relative to the unmodified PEM. Moreover, PEGBC modified PEM has a better thermal stability relative to ethylene carbonate based liquid electrolyte with enhanced ionic conductivity. Supported by NSF-DMR 1161070, 1502543 and REU 1359321.

  8. New HPLC method to determine ethyl carbamate in alcoholic beverages using fluorescence detection

    Herbert, P; Santos, L.; Bastos, M.; Barros, P.; Alves, A.

    2002-01-01

    A new methodology to the quantification of ethyl carbamate (EC) has been developed. This method allows the analysis by HPLC of ethyl carbarnate in samples of wine, fortified wine, and wine brandy, by a precolumn derivatization with 9-xanthydrol, and fluorescence detection. This does not require previous sample extraction or concentration. The method presents an average recovery of 96% among samples studied, a detection limit of 4.2 mug/L, and an average intermediate precision of 6.3%. The com...

  9. Efficient Lewis Acids Catalyzed Aza-Michael Reactions of Enones with Carbamates

    XIA Chun-Gu; XU Li-Wen

    2004-01-01

    The a-amino carbonyl functionality is not only a segment of biologically important natural products but also a versatile intermediate for the synthesis of nitrogen-containing compounds.1 The development of novel synthetic methods leading to a-amino ketone, a-amino acids or their derivatives has attracted much attention in organic synthesis.2 Among the traditional methods for generating a-amino carbonyl compounds, Mannich-type reaction is one of the classical and powerful methods.3 However, the classic Mannich reaction presents serious disadvantages, for example, there is still a drawback in that the silyl enolates have to be prepared from the corresponding carbonyl compounds. Alternatively, aza-Michael additions can be used to create carbon-heteroatom bonds by reaction of a,a-unsaturated carbonyl compounds with amines. Although recent advances have made this route more attractive, development of cheaper, simpler, and more efficient metal catalyst, especially which can be applied to chalcone, is highly desirable.In this paper, we demonstrated that the first aza-Michael reaction of chalcone with a less nucleophilic carbamates can be accomplished on Me3SiCFFeCl3 catalyst system under very mild conditions. Apart from experimental simplicity, the advantages of this methodology are the use of a very cheap Lewis acid catalyst and the insensitivity of the reaction mixture towards air and moisture.catalyst for aza-Michael reaction of chalcone and cyclic enones with carbamates. And with the cyclic enones with carbamates in dichloromethane at room temperature were also investigated. In this conjugate addition reaction, good to excellent yields of a-amino ketones were obtained with system could also mediates aza-Michael addition of carbamates to chalcone and derivatives.These new strategies opened efficient procedures for the synthesis of a-amino ketones under mild conditions.

  10. Bioactive Paper Sensor Based on the Acetylcholinesterase for the Rapid Detection of Organophosphate and Carbamate Pesticides

    2014-01-01

    In many countries, people are becoming more concerned about pesticide residues which are present in or on food and feed products. For this reason, several methods have been developed to monitor the pesticide residue levels in food samples. In this study, a bioactive paper-based sensor was developed for detection of acetylcholinesterase (AChE) inhibitors including organophosphate and carbamate pesticides. Based on the Ellman colorimetric assay, the assay strip is composed of a paper support (1...

  11. Management of exogenous intoxication by carbamates and organophosphates at an emergency unit

    Sydney Correia Leão

    2015-10-01

    Full Text Available Summary Objectives: to evaluate and indicate the procedure to be followed in the health unit, both for diagnosis and the treatment of acute exogenous intoxications by carbamates or organophosphates. Methods: a descriptive study based on retrospective analysis of the clinical history of patients diagnosed with intoxication by carbamates or organophosphates admitted at the emergency unit of the Hospital de Urgências de Sergipe Governador João Alves (HUSE between January and December of 2012. Some criteria were evaluated, such as: intoxicating agent; patient's age and gender; place of event, cause, circumstances and severity of the intoxication; as well as signs and symptoms of the muscarinic, nicotinic and neurological effects. Results: seventy patients (average age: 25±19.97 formed the study's population. It was observed that 77.14% of them suffered carbamate intoxication. However, organophosphate intoxications were more severe, with 68.75% of patients presenting moderate to severe forms. Suicide attempt was the leading cause of poisoning, with 62 cases (88.57% of total. Atropine administration was an effective therapeutic approach for treating signs and symptoms, which included sialorrhea (p=0.0006, nausea (p=0. 0029 and emesis (p lt0.0001. The use of activated charcoal was shown effective, both in combating the signs and symptoms presented by both patient groups (p <0.0001. Conclusion: it is concluded that the use of atropine and activated charcoal is highly effective to treat the signs and symptoms developed by patients presenting acute exogenous intoxication by carbamates or organophosphates.

  12. A Homogenous Luminescence Assay Reveals Novel Inhibitors for Giardia Lamblia Carbamate Kinase

    Chen, Catherine Z.; Southall, Noel; Galkin, Andrey; Lim, Kap; Juan J. Marugan; Kulakova, Liudmila; Shinn, Paul; van Leer, Danielle; Zheng, Wei; Herzberg, Osnat

    2012-01-01

    The human pathogen Giardia lamblia is an anaerobic protozoan parasite that causes giardiasis, one of the most common diarrheal diseases worldwide. Although several drugs are available for the treatment of giardisis, resistance to these drugs has been reported and is likely to increase. The Giardia carbamate kinase (glCK) plays an essential role in Giardia metabolism and has no homologs in humans, making it an attractive candidate for anti-Giardia drug development. We have developed a luminesc...

  13. Deconvolution Method for Determination of the Nitrogen Content in Cellulose Carbamates

    2001-01-01

    Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitrogen content for CC can be obtained by using the deconvolution method when the nitrogen content is less than 3.5%. The relationship between the nitrogen content and the absorption intensity ratio of the corresponding separated absorption peaks in FTIR spectra has been expressed by an equation precisely.

  14. Determination of Ethyl Carbamate in Alcoholic Beverages and Fermented Foods Sold in Korea

    Ryu, Dayeon; Choi, Bogyoung; Kim, Eunjoo; Park, Seri; Paeng, Hwijin; Kim, Cho-il; Lee, Jee-yeon; Yoon, Hae Jung; Koh, Eunmi

    2015-01-01

    Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were d...

  15. Methyl gallate

    Silvina Pagola

    2009-02-01

    Full Text Available The crystal structure of the title compound (systematic name: methyl 3,4,5-trihydroxybenzoate, C8H8O5, is composed of essentially planar molecules [maximum departures from the mean carbon and oxygen skeleton plane of 0.0348 (10 Å]. The H atoms of the three hydroxyl groups, which function as hydrogen-bond donors and acceptors simultaneously, are oriented in the same direction around the aromatic ring. In addition to two intramolecular hydrogen bonds, each molecule is hydrogen bonded to six others, creating a three-dimensional hydrogen-bonded network.

  16. Methyl gallate.

    Bebout, Deborah; Pagola, Silvina

    2009-01-01

    THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND (SYSTEMATIC NAME: methyl 3,4,5-trihydroxy-benzoate), C(8)H(8)O(5), is composed of essentially planar mol-ecules [maximum departures from the mean carbon and oxygen skeleton plane of 0.0348 (10) Å]. The H atoms of the three hydroxyl groups, which function as hydrogen-bond donors and acceptors simultaneously, are oriented in the same direction around the aromatic ring. In addition to two intra-molecular hydrogen bonds, each mol-ecule is hydrogen bonded to six others, creating a three-dimensional hydrogen-bonded network. PMID:21581923

  17. Methyl gallate

    Silvina Pagola; Deborah Bebout

    2009-01-01

    The crystal structure of the title compound (systematic name: methyl 3,4,5-trihydroxybenzoate), C8H8O5, is composed of essentially planar molecules [maximum departures from the mean carbon and oxygen skeleton plane of 0.0348 (10) Å]. The H atoms of the three hydroxyl groups, which function as hydrogen-bond donors and acceptors simultaneously, are oriented in the same direction around the aromatic ring. In addition to two intramolecular hydrogen bonds, each molecule is hydroge...

  18. Salicylanilide N-monosubstituted carbamates: Synthesis and in vitro antimicrobial activity.

    Krátký, Martin; Vinšová, Jarmila

    2016-03-15

    The research of innovative antimicrobial agents represents a cutting edge topic. Hence, we synthesized and characterised novel salicylanilide N-monosubstituted carbamates. Twenty compounds were evaluated in vitro against eight bacterial strains and eight fungal species. The lowest minimum inhibitory concentrations (MICs) were found to be ⩽0.49μM. Genus Staphylococcus, including methicillin-resistant Staphylococcus aureus, and fungus Trichophyton mentagrophytes showed uniformly the highest rate of susceptibility, whilst Gram-negative bacteria and most of the fungi were less susceptible. A wide range of carbamates provided comparable or superior in vitro antimicrobial activity in comparison to established drugs. Interestingly, extended-spectrum β-lactamase producing strain of Klebsiella pneumoniae was inhibited with MICs starting from 31.25μM. With respect to Staphylococci, 2-[(4-bromophenyl)carbamoyl]-4-chlorophenyl phenylcarbamate exhibited the lowest MIC values (⩽0.98μM). 2-[(4-Bromophenyl)carbamoyl]-4-chlorophenyl benzylcarbamate showed the widest spectrum of antifungal action. The results indicate that some salicylanilide carbamates can be considered to be promising candidates for future investigation. PMID:26879856

  19. Preparation of sintered silver nanosheets by coating technique using silver carbamate complex

    Ahn, Hee-Yong; Cha, Jae-Ryung; Gong, Myoung-Seon, E-mail: msgong@dankook.ac.kr

    2015-03-01

    This study describes a coating technique approach for large-scale preparation of sintered silver nanosheets whose lateral dimensions were controlled in the thickness range of 50–65 nm. These procedures involved coating water-soluble poly (vinyl alcohol) (PVA) and silver 2-ethylhexylcarbamate (Ag-EHC), as well as thermal reduction of a silver precursor by heating at 150 °C, followed by dissolving away the PVA layer with alcoholic water. When the silver carbamate layer on the PVA layer was heated to 150 °C, the silver carbamate layer was thermally reduced and directed to grow into uniform sintered nanosheets with aspect ratios as high as 1000. The multi-stacked PVA/Ag structures and sintered silver nanosheets were confirmed by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Measurements of the conductive property at room temperature indicated that these nanosheets were electrically continuous with a resistivity of approximately 7.3 × 10{sup −6} Ω cm. - Highlights: • A coating technique is used to make sintered Ag nanosheets. • PVA and silver carbamate act as a separation layer and a silver precursor. • The Ag nanosheets have thickness width 50–60 nm and width up to hundred μm. • The Ag nanosheets showed a resistivity of ca. 7.3 × 10{sup −6} Ω cm.

  20. 19F nuclear magnetic resonance analysis of the carbamate reaction of alpha-fluoro-beta-alanine (FBAL), the major catabolite of fluoropyrimidines. Application to FBAL carbamate determination in body fluids of patients treated with 5'-deoxy-5-fluorouridine

    alpha-Fluoro-beta-alanine (FBAL), the major catabolite of the antineoplastic fluoropyrimidines, is an amino acid which is in equilibrium with its carbamate derivative in weakly alkaline aqueous solutions containing carbonate. In both water and control biological fluids (urine, plasma) spiked with FBAL (and sodium bicarbonate, in some cases), 19F NMR was used: (i) to determine the pH range over which FBAL carbamate is present (pH greater than or equal to 7), the maximum concentration formed occurring around pH 9, (ii) to show that the amino group of FBAL interacts very slowly with a non-protein plasma component to form a compound X, unstable in acid medium. The presumed structure of X is RCONHCH2CHFCOOH, with R different from an alkyl group but still unidentified. The behavior of FBAL in urine and plasma of rats treated with FBAL or 5'-deoxy-5-fluorouridine (5'-dFUrd), a prodrug of 5-fluorouracil, and from patients treated with 5'-dFUrd was investigated. FBAL carbamate was not present in acid medium and was therefore absent in acidic human urine. However, it was found in alkaline rat urine. FBAL carbamate was found in plasma along with the compound X. The 19F NMR spectra of FBAL and derivatives are complex since alpha-fluoro-beta-ureido-propionic acid, the precursor of FBAL in the catabolic pathway of antineoplastic fluoropyrimidines, produces a signal overlapping that of FBAL carbamate, and very close to that of compound X

  1. Probabilistic assessment of the cumulative dietary acute exposure of the population of Denmark to organophosphorus and carbamate pesticides

    Jensen, Bodil Hamborg; Petersen, Annette; Christensen, Tue

    2009-01-01

    Organophosphorus and carbamate pesticides are acetylcholinesterase-inhibiting pesticides and as such have a common mode of action. We assessed the cumulative acute exposure of the population of Denmark to 25 organophosphorus and carbamate pesticide residues from the consumption of fruit, vegetables...... and cereals. The probabilistic approach was used in the assessments. Residue data obtained from the Danish monitoring programme carried out in the period 2004-2007, which included 6704 samples of fruit, vegetables and cereals, were used in the calculations. Food consumption data were obtained from...... the nationwide dietary survey conducted in 2000-2002. Contributions from 43 commodities were included in the calculations. We used the relative potency factor (RPF) approach to normalize the toxicity of the various organophosphorus and carbamate pesticides to the two index compounds chlorpyriphos...

  2. Role of B-esterases in assessing toxicity of organophosphorus (chlorpyrifos, malathion) and carbamate (carbofuran) pesticides to Daphnia magna.

    Barata, Carlos; Solayan, Arun; Porte, Cinta

    2004-02-10

    In this study, the cladoceran Daphnia magna was exposed to two model organophosphorous and one carbamate pesticides including malathion, chlorpyrifos and carbofuran to assess acetylcholinesterase (AChE) and carboxylesterase (CbE) inhibition and recovery patterns and relate those responses with individual level effects. Our results revealed differences in enzyme inhibition and recovery patterns among the studied esterase enzymes and pesticides. CbE was more sensitive to organophosphorous than AChE, whereas both CbE and AChE showed equivalent sensitivities to the carbamate carbofuran. Recovery patterns of AChE and CbE activities following exposure to the studied pesticides were similar with 80-100% recoveries taking place 12 and 96 h after exposure to organophosphorous and carbamates pesticides, respectively. The physiological role of AChE and CbE inhibition patterns in Daphnia was examined by using organophosphorous and carbamate compounds alone and with specific inhibitors of CbE. Under exposure to organophosphorous pesticides, survival of Daphnia juveniles was impaired at AChE inhibition levels higher than 50% whereas under exposure to the carbamate carbofuran low levels of AChE inhibition affected mortality. Inhibition of CbE by 80-90% increased toxicity to organophosphorous and carbamate pesticides by up to two- and four-fold, respectively. Our results suggest that both AChE and CbE enzymes are involved in determining toxicity of Daphnia to the studied chemicals and that AChE inhibition levels higher than 50% can be considered of environmental concern to Daphnia species. PMID:15036868

  3. Application of Physiologically Based Pharmacokinetic/Pharmacodynamic Modeling in Cumulative Risk Assessment for N-Methyl Carbamate Insecticides

    Human exposure to xenobiotics may occur through multiple pathways and routes of entry punctuated by exposure intervals throughout a work or leisure day. Exposure to a single environmental chemical along multiple pathways and routes (aggregate exposure) may have an influence on an...

  4. The role of kaolin particles in the performance of a carbamate-based biocide for water bacterial control

    Maria Olivia Pereira; Maria João Vieira; Melo, Luis F.

    2002-01-01

    The influence of kaolin particles on the activity of Pseudomonas fuorescens and on the efficacy of a carbamate-based biocide was investigated. The results indicated that kaolin particles stimulated the activity of the bacteria for all buffered pH values studied (5, 7, and 9); this effect being more evident for the tests carried out at pH 5 and 9. The presence of the clay in P. fuorescens suspensions decreased the efficiency of disinfection of the carbamate. The results also showed that kaolin...

  5. In Situ Blood-Brain Barrier Permeability of a C-10 Paclitaxel Carbamate

    Ballatore, Carlo; Zhang, Bin; Trojanowski, John Q.; Lee, Virginia M.-Y.; Smith, Amos B.

    2008-01-01

    We report the synthesis and blood-brain barrier (BBB) permeability of 14C-CNDR-29, a paclitaxel C-10 carbamate derivative shown to be devoid of P-glycoprotein (Pgp)-interactions, in an in situ mouse brain perfusion model, in comparison with 14C-paclitaxel. The results presented reveal a 3–4 fold higher BBB-permeability for the C-10 modified taxane compared to paclitaxel. These results support the notion that circumvention of Pgp-mediated efflux can lead to higher BBB-permeability. Further stu...

  6. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography

    Belisle, A.A.; Swineford, D.M.

    1988-01-01

    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  7. toxicological effect of carbamate (methavin) on some biochemical activities in white rats

    this work aims to study the toxic effect, which resulted from the direct or indirect exposure to the applied insecticide (methomyl), which was formerly known as lannate, that belongs to carbamate group. this study includes the determination of the effect of the methomyl on some biochemical activities in white rats as well as the changes in some hormonal levels. since the mentioned insecticide used in egypt from many years ago, which necessitated numerous studies on its effect to various organs of the human body by treating some animals which are closely similar to human construction

  8. Radioiodinated 2-nitrobenzyl carbamates as bioreductive alkylating agents for tissue hypoxia

    Three N-methylcarbamates of iodonitrobenzyl alcohols (4-iodo-2-nitrobenzyl alcohol 2, 5-iodo-2-nitrobenzyl alcohol 3 and 4-iodo-2,6-dinitrobenzyl alcohol 4) bearing [125I] have been prepared and characterized for their lipophilicity, their reduction potentials and the in vivo lability of the radioiodine in healthy mice. Based upon these results, 2 and 4 were tested in tumour-bearing mice showing limited uptake of radioactivity in tumours and a tumour-to-blood ratio of less than 1. Consequently these particular carbamates are not satisfactory as hypoxia imaging agents. (Author)

  9. The P450 CYP6Z1 confers carbamate/pyrethroid cross-resistance in a major African malaria vector beside a novel carbamate-insensitive N485I acetylcholinesterase-1 mutation.

    Ibrahim, Sulaiman S; Ndula, Miranda; Riveron, Jacob M; Irving, Helen; Wondji, Charles S

    2016-07-01

    Carbamates are increasingly used for vector control notably in areas with pyrethroid resistance. However, a cross-resistance between these insecticides in major malaria vectors such as Anopheles funestus could severely limit available resistance management options. Unfortunately, the molecular basis of such cross-resistance remains uncharacterized in An. funestus, preventing effective resistance management. Here, using a genomewide transcription profiling, we revealed that metabolic resistance through upregulation of cytochrome P450 genes is driving carbamate resistance. The P450s CYP6P9a, CYP6P9b and CYP6Z1 were the most upregulated detoxification genes in the multiple resistant mosquitoes. However, in silico docking simulations predicted CYP6Z1 to metabolize both pyrethroids and carbamates, whereas CYP6P9a and CYP6P9b were predicted to metabolize only the pyrethroids. Using recombinant enzyme metabolism and inhibition assays, we demonstrated that CYP6Z1 metabolizes bendiocarb and pyrethroids, whereas CYP6P9a and CYP6P9b metabolize only the pyrethroids. Other upregulated gene families in resistant mosquitoes included several cuticular protein genes suggesting a possible reduced penetration resistance mechanism. Investigation of the target-site resistance in acetylcholinesterase 1 (ace-1) gene detected and established the association between the new N485I mutation and bendiocarb resistance (odds ratio 7.3; P carbamate resistance and improve the design of effective resistance management strategies to control this malaria vector. PMID:27135886

  10. Bioactive Paper Sensor Based on the Acetylcholinesterase for the Rapid Detection of Organophosphate and Carbamate Pesticides

    Mohamed E. I. Badawy

    2014-01-01

    Full Text Available In many countries, people are becoming more concerned about pesticide residues which are present in or on food and feed products. For this reason, several methods have been developed to monitor the pesticide residue levels in food samples. In this study, a bioactive paper-based sensor was developed for detection of acetylcholinesterase (AChE inhibitors including organophosphate and carbamate pesticides. Based on the Ellman colorimetric assay, the assay strip is composed of a paper support (1×10 cm, onto which a biopolymer chitosan gel immobilized in crosslinking by glutaraldehyde with AChE and 5,5′-dithiobis(2-nitrobenzoic acid (DTNB and uses acetylthiocholine iodide (ATChI as an outside reagent. The assay protocol involves introducing the sample to sensing zone via dipping of a pesticide-containing solution. Following an incubation period, the paper is placed into ATChI solution to initiate enzyme catalyzed hydrolysis of the substrate, causing a yellow color change. The absence or decrease of the yellow color indicates the levels of the AChE inhibitors. The biosensor is able to detect organophosphate and carbamate pesticides with good detection limits (methomyl=6.16×10-4 mM and profenofos=0.27 mM and rapid response times (~5 min. The results show that the paper-based biosensor is rapid, sensitive, inexpensive, portable, disposable, and easy-to-use.

  11. Vapor Pressure, Vaporization Enthalpy, Standard Enthalpy of Formation and Standard Entropy of n-Butyl Carbamate

    Zuoxiang Zeng⁎; Zhihong Yang; Weilan Xue⁎; Xiaonan Li

    2014-01-01

    The vapor pressures of n-butyl carbamate were measured in the temperature range from 372.37 K to 479.27 K and fitted with Antoine equation. The compressibility factor of the vapor was calculated with the Virial equation and the second virial coefficient was determined by the Vetere model. Then the standard enthalpy of vaporization for n-butyl carbamate was estimated. The heat capacity was measured for the solid state (299.39–324.2 K) and liquid state (336.65–453.21 K) by means of adiabatic calorimeter. The standard en-thalpy of formationΔfHϴ[crystal (cr),298.15 K] and standard entropy Sϴ(crystal,298.15 K) of the sub-stance were calculated on the basis of the gas-phase standard enthalpy of formationΔfHϴ(g,298.15 K) and gas-phase standard entropy Sϴ(g,298.15 K), which were estimated by the Benson method. The results are acceptable, validated by a thermochemical cycle.

  12. Crystal structures of carbamate kinase from Giardia lamblia bound with citric acid and AMP-PNP.

    Kap Lim

    Full Text Available The parasite Giardia lamblia utilizes the L-arginine dihydrolase pathway to generate ATP from L-arginine. Carbamate kinase (CK catalyzes the last step in this pathway, converting ADP and carbamoyl phosphate to ATP and ammonium carbamate. Because the L-arginine pathway is essential for G. lamblia survival and absent in high eukaryotes including humans, the enzyme is a potential target for drug development. We have determined two crystal structures of G. lamblia CK (glCK with bound ligands. One structure, in complex with a nonhydrolyzable ATP analog, adenosine 5'-adenylyl-β,γ-imidodiphosphate (AMP-PNP, was determined at 2.6 Å resolution. The second structure, in complex with citric acid bound in the postulated carbamoyl phosphate binding site, was determined in two slightly different states at 2.1 and 2.4 Å resolution. These structures reveal conformational flexibility of an auxiliary domain (amino acid residues 123-170, which exhibits open or closed conformations or structural disorder, depending on the bound ligand. The structures also reveal a smaller conformational change in a region associated the AMP-PNP adenine binding site. The protein residues involved in binding, together with a model of the transition state, suggest that catalysis follows an in-line, predominantly dissociative, phosphotransfer reaction mechanism, and that closure of the flexible auxiliary domain is required to protect the transition state from bulk solvent.

  13. Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2

    Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B.

    2016-05-01

    The anilide anion ( m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion ( m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion ( m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

  14. Ionic carbamate photoacid/photobase generators for the advancement of dual-tone photolithography

    Hallett-Tapley, Geniece L.; Wee, Tse-Luen; Eldo, Joby; Jackson, Edward A.; Blackwell, James M.; Scaiano, Juan C.

    2012-03-01

    Current work in lithographic patterning has been carried out using 193 nm excitation sources, limiting the pitch division to approximately λ/2 and, thus, the advancement of Moore's law. Recently, double patterning has emerged as a potential extension of 193 nm techniques as two lines can be patterned in one exposure. In this contribution, the double patterning features of single component carbamate photoacid/photobase generators (PAG/PBG) are examined. At lower exposure doses, sulfonic acid is generated, while at higher doses, a photochemical rearrangement is initiated to activate the PBG. Optimally, at intermediate doses, photoacid and photobase components can exist concurrently resulting in the desired dual tone lithographic features. The energy required to initiate dual tone behavior can be tailored through co-added amine quenchers and carbamate concentration. Using ellipsometry, the energy required for the resists to have the first sign of photoacid generation (film dissolution), E0, and at the energy required for photobase activation (En) were determined, as this value dictates the ability to achieve the desired pitch division.

  15. Blackberry subjected to in vitro gastrointestinal digestion affords protection against Ethyl Carbamate-induced cytotoxicity.

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Su, Hongming; Zheng, Xiaodong

    2016-12-01

    Ethyl Carbamate (EC) was detected in many fermented foods. Previous studies indicated that frequent exposure to ethyl carbamate may increase the risk to suffer from cancers. Blackberry is rich in polyphenols and possesses potent antioxidant activity. This study aims to investigate the protective effect of blackberry homogenates produced before (BH) and after in vitro simulated gastrointestinal digestion (BD) on EC-induced toxicity in Caco-2 cells. Our results showed that blackberry homogenates after digestion (BD) was more effective than that before digestion (BH) in ameliorating EC-induced toxicity in Caco-2 cells. Further investigation revealed that BD remarkably attenuated EC-induced toxicity through restoring mitochondrial function, inhibiting glutathione depletion and decreasing overproduction of intracellular reactive oxygen species. Additionally, LC-MS result implied that the better protective capacity of BD may be related to the increased content of two anthocyanins (cyanidin-3-glucoside and cyanidin-3-dioxalyglucoside). Overall, the present study may give implication to prevent EC-induced health problem. PMID:27374576

  16. Kapok oil methyl esters

    The increased need for biodiesel feedstocks has caused various vegetable oils to be examined for this purpose. In the present work, the methyl esters of kapok (Ceiba pentandra) oil were prepared. The essential fuel properties were comprehensively determined and evaluated in comparison to specifications in biodiesel standards and some prior results. The kinematic viscosity of kapok oil methyl esters was greater than expected, an observation traced to the elevated amounts of methyl esters with cyclic moieties. Overall, kapok oil is a potential biodiesel feedstock. The 1H and 13C NMR spectra of kapok methyl esters are reported. - Highlights: • Methyl esters of kapok oil generally acceptable as a biodiesel fuel. • Kapok oil methyl esters a fuel with elevated content of fatty acid methyl esters containing cyclic moieties. • Kinematic viscosity of kapok oil methyl esters elevated likely due to fatty ester methyl esters with cyclic moieties. • Discusses and compares present results with prior literature

  17. Demonstration of a functional requirement for the carbamate nitrogen of ribulosebisphosphate carboxylase/oxygenase by chemical rescue

    Ribulosebisphosphate carboxylase/oxygenase is reversibly activated by the reaction of Co2 with a specific lysyl residue to form a carbamate that coordinates an essential Mg2+ cation. Surprisingly, the Lys191→Cys mutant protein, in the presence of Co2 and Mg2+ exhibits tight binding of the reaction intermediate analogue 2-carboxyarabinitol bisphosphate a property normally equated with effective coordination of the Mg2+ by the carbamate. Catalytic ineptness of the Cys191 mutant protein, despite its ability to coordinate Mg2+ properly, might be due to the absence of the carbamate nitrogen. To investigate this possibility, the authors have evaluated the ability of exogenous amines to restore catalytic activity to the mutant protein. Significantly, the Cys191 protein manifests ribulose bisphosphate dependent fixation of 14CO2 when incubated with aminomethanewsulfonate but not ethanesulfonate. This novel activity reflects a Km value for ribulose bisphosphate which is not markedly perturbed relative to wild-type enzyme, a Km for Mg2+ which is in fact decreased 10-fold, and rate saturation with respect to aminomethanesulfonate. Chromatographic and spectrophotometric analyses reveal the product of CO2 fixation to be D-3-phosphoglycerate while turnover of [1-3H]ribulose bisphosphate into [3H]phosphoglycolate confirms oxygenase activity. The authors conclude that aminomethanesulfonate restored ribulosebisphosphate carboxylase/oxygenase activities to the Cys191 mutant protein by providing a nitrogenous function which satisfies a catalytic demand normally met by the carbamate nitrogen of Lys191

  18. Synthesis and biological activity of beta-glucuronyl carbamate-based prodrugs of paclitaxel as potential candidates for ADEPT

    deBont, DBA; Leenders, RGG; Haisma, HJ; vanderMeulenMuileman, [No Value; Scheeren, HW

    1997-01-01

    The syntheses of prodrugs of paclitaxel, which can be used in ADEPT in order to target paclitaxel towards tumor cells, are described. The prodrugs 1 and 2a,b consist of a spacer molecule connected via a carbamate linkage to a beta-glucuronic acid. The spacer molecule is also connected via an ester l

  19. Structural relaxation accompanied by photo-induced chromatic phase transition of polydiacetylenes with butylene-N-difluorophenyl carbamate side chains

    Maekawa, Yuuki; Sakamoto, Naoya; Kokado, Ryousuke; Kajimoto, Naoshi; Izumi, Yuuichiro [Department of Materials Science and Chemistry, Wakayama University, 930 Sakaedani, Wakayama (Japan); Itoh, Chihiro, E-mail: citoh@sys.wakayama-u.ac.jp [Department of Materials Science and Chemistry, Wakayama University, 930 Sakaedani, Wakayama (Japan)

    2013-01-15

    We have studied the phase transition of poly-5,7-dodecadiyne-1,12-diol bis[2,4-difluorophenyl carbamate] (PDA-2,4-DFPC) and poly-5,7-dodecadiyne-1,12-diol bis[3,4-difluorophenyl carbamate] (PDA-3,4-DFPC) by visible reflection spectroscopy and mid-infrared absorption spectroscopy. Both PDA-2,4-DFPC and PDA-3,4-DFPC show the reflection spectra characterized by a sharp peak at around 1.9 eV at room temperature. While PDA-3,4-DFPC shows thermochromic phase transition to the phase showing the reflection spectrum with a peak around 2.2 eV above 120 Degree-Sign C, PDA-2,4-DFPC shows no abrupt change of the reflection spectrum. However, PDA-2,4-DFPC shows drastic change of the reflection spectrum under 532-nm CW-laser excitation. Based on these results, we can draw the following two conclusions. First, the phase transition behavior of PDA can be controlled by modifying the side-chain structure. Second, we demonstrate that thermally inaccessible phase of PDA is induced by the photo-excitation. By measuring mid-infrared absorption of PDAs, we elucidated that conformational change of side chains is accompanied with the phase transition. Based on the results, we discussed the role of the side chain in the phase transition. - Highlights: Black-Right-Pointing-Pointer We have synthesized polydiacetylene (PDA) with difluorophenyl carbamate side chain. Black-Right-Pointing-Pointer PDAs show distinct phase transition (PT) depending on the side-chain structure. Black-Right-Pointing-Pointer PDA with 3,4-difluorophenyl carbamate shows PT by thermal stimulation. Black-Right-Pointing-Pointer However, PDA with 2,4-difluorophenyl carbamate shows PT only under photo-excitation.

  20. Dissociation dynamics of methylal

    Beaud, P.; Frey, H.-M.; Gerber, T.; Mischler, B.; Radi, P.P.; Tzannis, A.-P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

  1. From immunotoxicity to carcinogenicity: the effects of carbamate pesticides on the immune system.

    Dhouib, Ines; Jallouli, Manel; Annabi, Alya; Marzouki, Soumaya; Gharbi, Najoua; Elfazaa, Saloua; Lasram, Mohamed Montassar

    2016-05-01

    The immune system can be the target of many chemicals, with potentially severe adverse effects on the host's health. In the literature, carbamate (CM) pesticides have been implicated in the increasing prevalence of diseases associated with alterations of the immune response, such as hypersensitivity reactions, some autoimmune diseases and cancers. CMs may initiate, facilitate, or exacerbate pathological immune processes, resulting in immunotoxicity by induction of mutations in genes coding for immunoregulatory factors and modifying immune tolerance. In the present study, direct immunotoxicity, endocrine disruption and inhibition of esterases activities have been introduced as the main mechanisms of CMs-induced immune dysregulation. Moreover, the evidence on the relationship between CM pesticide exposure, dysregulation of the immune system and predisposition to different types of cancers, allergies, autoimmune and infectious diseases is criticized. In addition, in this review, we will discuss the relationship between immunotoxicity and cancer, and the advances made toward understanding the basis of cancer immune evasion. PMID:26988364

  2. Occurrence and Distribution of Carbamate Pesticides and Metalaxyl in Southern Ontario Surface Waters 2007-2010.

    Struger, John; Grabuski, Josey; Cagampan, Steve; Sverko, Ed; Marvin, Chris

    2016-04-01

    Surface water sampling in 2007-2010 measured the occurrence of carbamates and metalaxyl during base flow conditions and wet weather events in southern Ontario surface waters. Carbaryl, metalaxyl and pirimicarb were the most frequently detected compounds. In 2008 these three compounds were detected in over 50 % of the samples. Overall mean concentrations of carbaryl and metalaxyl over the course of the study (2007-2010) were 15 and 18 ng/L, respectively. Elevated concentrations of carbaryl (~100 to ~950 ng/L) appeared associated with wet weather (high flow) events, while highest concentrations of metalaxyl (~20-1330 ng/L) were correlated with base flow conditions. We attributed these observations as the result of runoff of carbaryl from the watershed during rain events, while metalaxyl contamination may have resulted primarily from spray drift. PMID:26754544

  3. Biochemical and Histopathological Changes in The Rat Following Exposure to a Carbamate Pesticide

    Oxamyl is a carbamate pesticide with an oral LD50 of 5.4 mg/kg for male rats. To evaluate the subacute toxicity of the compound, two groups of male rats were dosed with 0.9 and 2.5 mg/kg/day of the pesticide, for 16 days. Toxicological evaluation included clinical chemistry and histopathological changes at the end of the study. The compound significantly altered serum alkaline phosphatase, uric acid, cholesterol, creatinine, blood urea nitrogen (BUN), serum glutamic pyruvic transaminase (SGPT and testosterone. Liver, Kidney and testicular histology revealed mild degenerative changes in the liver with the lower dose and significant degenerative changes with increased lymphocytic infiltrate with the higher dose and mild degenerative changes of the kidney with the higher dose only. Examination of the testis revealed no pathological changes at both dose levels

  4. A general method for tritium labelling of benzimidazole carbamates by catalytic exchange in dioxane solutions

    Lacey, E. (Commonwealth Scientific and Industrial Research Organization, Glebe, NSW (Australia). Div. of Animal Health, McMaster Lab.); Dawson, M. (Sydney Univ. (Australia). Dept. of Pharmacy); Long, M.A.; Than, C. (New South Wales Univ., Kensington (Australia). School of Chemistry)

    1989-12-01

    Benzimidazole carbamates (BZCs) act as inhibitors of the tubulin-microtubule equilibria in eukaryotic organisms. Recently drug resistance to this class of compounds in helminth parasites has been shown to be due to a reduced ability of resistant tubulin to bind BZCs. In order to quantitate the nature of the tubulin-BZC interaction a general method for the specific tritium labelling of BZCs has been developed. The BZCs: mebendazole, oxfendazole, parbendazole, oxibendazole, albendazole and fenbendazole were labelled by catalytic exchange using palladium on calcium carbonate in pure dioxane at 60{sup 0}C under tritium gas. The position of label incorporation for tritiated albendazole was determined by tritium-NMR as the 4-position of benzimadazole nucleus. The yields for individual BZCs varied from 8 to 68% for a range of specific activity of 0.44 to 13.4 Ci/mmole. (author).

  5. A general method for tritium labelling of benzimidazole carbamates by catalytic exchange in dioxane solutions

    Benzimidazole carbamates (BZCs) act as inhibitors of the tubulin-microtubule equilibria in eukaryotic organisms. Recently drug resistance to this class of compounds in helminth parasites has been shown to be due to a reduced ability of resistant tubulin to bind BZCs. In order to quantitate the nature of the tubulin-BZC interaction a general method for the specific tritium labelling of BZCs has been developed. The BZCs: mebendazole, oxfendazole, parbendazole, oxibendazole, albendazole and fenbendazole were labelled by catalytic exchange using palladium on calcium carbonate in pure dioxane at 600C under tritium gas. The position of label incorporation for tritiated albendazole was determined by tritium-NMR as the 4-position of benzimadazole nucleus. The yields for individual BZCs varied from 8 to 68% for a range of specific activity of 0.44 to 13.4 Ci/mmole. (author)

  6. Synthesis of kenaf cellulose carbamate and its smart electric stimuli-response.

    Gan, Sinyee; Piao, Shang Hao; Choi, Hyoung Jin; Zakaria, Sarani; Chia, Chin Hua

    2016-02-10

    Cellulose carbamate (CC) was produced from kenaf core pulp (KCP) via a microwave reactor-assisted method. The formation of CC was confirmed by Fourier transform infrared spectroscopy and nitrogen content analysis. The degree of substitution, zeta potential and size distribution of CC were also determined. The CC was characterized with scanning electron microscopy, X-ray diffraction and thermogravimetry analysis. The CC particles were then dispersed in silicone oil to prepare CC-based anhydrous electric stimuli-responsive electrorheological (ER) fluids. Rhelogical measurement was carried out using rotational rheometer with a high voltage generator in both steady and oscillatory shear modes to examine the effect of electric field strength on the ER characteristics. The results showed that the increase in electric field strength has enhanced the ER properties of CC-based ER fluid due to the chain formation induced by electric polarization among the particles. PMID:26686181

  7. Assessment of Organophosphate and Carbamate Pesticide Residues in Cigarette Tobacco with a Novel Cell Biosensor

    Spiridon Kintzios

    2008-04-01

    Full Text Available The conventional analysis of pesticide residues in analytical commodities, such as tobacco and tobacco products is a labor intensive procedure, since it is necessary to cover a wide range of different chemicals, using a single procedure. Standard analysis methods include extensive sample pretreatment (with solvent extraction and partitioning phases and determination by GC and HPLC to achieve the necessary selectivity and sensitivity for the different classes of compounds under detection. As a consequence, current methods of analysis provide a limited sample capacity. In the present study, we report on the development of a novel cell biosensor for detecting organophosphate and carbamate pesticide residues in tobacco. The sensor is based on neuroblastoma N2a cells and the measurement of changes of the cell membrane potential, according to the working principle of the Bioelectric Recognition Assay (BERA. The presence of pesticide residues is detected by the degree of inhibition of acetylcholine esterase (AChE. The sensor instantly responded to both the organophoshate pesticide chlorpyriphos and the carbamate carbaryl in a concentration-dependent pattern, being able to detect one part per billion (1 ppb. Additionally, tobacco leaf samples (in blended dry form were analyzed with both the novel biosensor and conventional methods, according to a double-blind protocol. Pesticide residues in tobacco samples caused a considerable cell membrane hyperpolarization to neuroblastoma cells immobilized in the sensor, as indicated by the increase of the negative sensor potential, which was clearly distinguishable from the sensor’s response against pesticide-free control samples. The observed response was quite reproducible, with an average variation of +5,6%. Fluorescence microscopy observations showed that treatment of the cells with either chlorpyrifos or carbaryl was associated with increased [Ca2+]cyt . The novel biosensor offers fresh

  8. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica–hydrogel hybrid microbeads

    Highlights: • Silica–hydrogel hybrid microbeads were used to develop suspension array. • The results in detecting pesticides agree well with those from LC–MS/MS. • The method showed the good capability for multiplex analysis of pesticides residues. - Abstract: A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica–hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02 ng/mL, 0.012 ng/mL, 0.04 ng/mL, 0.05 ng/mL and 0.1 ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography–tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables

  9. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica–hydrogel hybrid microbeads

    Wang, Xuan [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China); Mu, Zhongde; Shangguan, Fengqi [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu (China); Liu, Ran; Pu, Yuepu [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China); Yin, Lihong, E-mail: lhyin@seu.edu.cn [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China)

    2014-05-01

    Highlights: • Silica–hydrogel hybrid microbeads were used to develop suspension array. • The results in detecting pesticides agree well with those from LC–MS/MS. • The method showed the good capability for multiplex analysis of pesticides residues. - Abstract: A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica–hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02 ng/mL, 0.012 ng/mL, 0.04 ng/mL, 0.05 ng/mL and 0.1 ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography–tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables.

  10. Novel Preparation of Methoxy Carbamates of 1-Protected Indole- 3-methylamines as Precursor of Indole-3-methylamine

    SONG,Hao; XIN,Jun-Guo; WANG,Yin; CHEN,Wei; YANG,Jun; QIN,Yong

    2004-01-01

    @@ Indole-3-methylamine (1) has been well demonstrated to be a very useful intermediate as a pharmaceutical building block and starting material for syntheses of phytoalexins.[1] The instability of indole-3-methylamine (1) has undoubtedly restricted its application in synthetic chemistry. Hofmann rearrangement that directly converts carboxamides to alky carbamates in the presence of alcohol required unexceptionally a strong base,[2] which devaluated the possible usefulness of Hofmann rearrangement in preparation of base sensitive amines, especially for the preparation of unstable indole-3-methylamine (1). Herein we would like to report a convenient method for the preparation of alkyl carbamates of 1-protected indole-3-methylamines (4) via the diacetoxyiodobenzene (DIB) promoted Hofmann rearrangement under neutral condition.

  11. Solid-phase extraction of flavonoids in honey samples using carbamate-embedded triacontyl-modified silica sorbent.

    Liu, Houmei; Zhang, Mingliang; Guo, Yong; Qiu, Hongdeng

    2016-08-01

    In this study, carbamate-embedded triacontyl-modified silica (Sil-CBM-C30) is successfully prepared and used as an efficient sorbent for solid-phase extraction. The extraction performance of the resultant sorbent is evaluated with five flavonoids including myricetin, quercetin, luteolin, kaempferol and isorhamnetin. Main parameters, which affect extraction efficiencies, are carefully investigated and optimized. Comparative experiments between Sil-CBM-C30 and commercial C18 sorbents indicate that the extraction efficiencies of the former one surpass the latter one. The modification of carbamate-embedded triacontyl group on surface of silica causes analytes extracted by hydrophobic, hydrogen bonding and π-π interactions. Under optimal conditions, good linearities and satisfied LODs and LOQs are achieved. The SPE-HPLC-DAD method is successfully developed and applied for the honey sample analysis. PMID:26988475

  12. 氨基甲酸酯清洁合成技术进展%Progress in clean synthesis of carbamates

    谭学峰; 王越; 胡静; 马飞; 王公应

    2012-01-01

    综述了氨基甲酸酯清洁合成技术的发展现状和趋势,并对所用催化剂体系做了详细评述,认为碳酸酯胺解法是最具产业化前景的氨基甲酸酯清洁合成路线,高活性催化剂结合适宜的工艺流程是产业化成功的关键.%Recent progress and trends in clean synthesis of carbamates were reviewed, including a detail commentary on the catalyst systems. Ammonolysis of dimethyl carbonate (DMC) was considered to be the most promising industrial route for clean synthesis of carbamates. It was believed that developing high activity catalyst with suitable process would be the key to the industrial success.

  13. Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo

    Daniel-Mwuambete K.; Ponce-Gordo F.; Torrado J.; Torrado S.; Cuesta-Bandera C.

    2003-01-01

    Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on meb...

  14. Isotope separation of carbon-13 by counter-current column with exchange reaction between carbon dioxide and carbamic acid

    The isotope separation performance of carbon-13 with exchange reaction between CO2 and carbamic acid was studied and some factors for the counter-current column were studied for improving the overall performance. The working fluid for the experiments was a solution of DNBA, (C4H9)2NH, and n-octane mixture. The rate-controlling step of 13C transfer at temperatures higher than 10 deg C was the exchange reaction between carbamic acid and CO2 dissolved by physical absorption. The capacity coefficient of 13C transfer between gas and liquid in the counter-current column was successfully related to the product of three factors: the concentration of carbamic acid, the concentration of CO2 dissolved by physical absorption and the liquid holdup of the column. The liquid holdup was also an important factor. As the holdup increased, the isotope exchange rate and the overall separation factor of the column increased. However, the transient time to equilibrium was much longer. (author)

  15. Biodegradation of carbamate pesticides by natural river biofilms in different seasons and their effects on biofilm community structure

    This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1–59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0–27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water. -- Highlights: •Natural river biofilms showed high ability to degrade methomyl and carbofuran. •The presence of other pesticides caused certain effects on pesticide degradation. •Carbamate pesticides caused adverse effects on communities of diatoms and bacteria. •The tolerant diatoms and bacteria were found as potential pesticide-degraders. -- Biodegradation of carbamate pesticides by river biofilms

  16. Possible mechanisms for sensitivity to organophosphorus and carbamate insecticides in eastern screech-owls and American kestrels

    Vyas, N.B.; Thiele, L.A.; Garland, S.C.

    1998-01-01

    Effects of a single dietary exposure to fenthion and carbofuran on the survival, feeding behavior and brain ChE activity of eastern screech-owls, Otus asio and American kestrels, Falco sparverius, were evaluated. Birds were exposed to fenthion (23.6189.0 ppm) or carbofuran (31.7253.6 ppm) via meatballs. Carbofuran-exposed owls ate either = 80% of the meatball whereas all kestrels ate <= 10% of the meatball before exhibiting acute signs of toxicity. Fenthion-exposed owls and kestrels displayed a wide spectrum of meatball consumption (<10100%). Significant brain ChE inhibition was observed in dead and surviving kestrels exposed to fenthion and carbofuran and dead owls exposed to fenthion (P < 0.0001). Brain ChE activity of owls exposed to carbofuran that survived was not different from that of controls (P = 0.25). Data suggest: (1) slow feeding on a carbamate-contaminated item may provide limited protection from the toxicity of the chemical at certain rates of exposure; (2) the degree of ChE inhibition at neuromuscular junctions may be critical in determining the sensitivity of a species to a carbamate insecticide; (3) sensitivity may be a function of the ChE affinity for the carbamate inhibitor; and (4) the importance of neuromuscular junction ChE depression in determining the sensitivity of an animal may be species-specific.

  17. Precipitation of calcium carbonate from a calcium acetate and ammonium carbamate batch system

    Prah, J.; Maček, J.; Dražič, G.

    2011-06-01

    In this paper, we report a novel approach for preparing precipitated calcium carbonate using solutions of ammonium carbamate and calcium acetate as the sources of calcium and carbon dioxide, respectively. Two different concentrations of the starting solutions at three different temperatures (15, 25 and 50 °C) were used for the reaction. The influence of temperature and concentration on the polymorphism and the resulting morphology of calcium carbonate are discussed. The most important parameter for controlling a particular crystal structure and precipitate morphology were the concentrations of the initial solutions. When initial solutions with lower concentrations were used, the crystal form of the precipitate changed with time. Regardless the different polymorphism at different temperatures, after one day only the calcite form was detected in all samples, regardless of at which temperature the samples were prepared. At higher concentrations, pure vaterite or a mixture of vaterite and calcite were present at the beginning of the experiment. After one day, pure vaterite was found in the samples that were prepared at 15 and 25 °C. If calcium carbonate precipitated at 50 °C, the XRD results showed a mixture of calcite and vaterite regardless of the time at which the sample was taken. The morphology of calcium carbonate particles prepared at various conditions changed from calcite cubes to spherical particles of vaterite and aragonite needles. When a low starting concentration was used, the morphology at the initial stage was strongly affected by the temperature at which the experiments were conducted. However, after one day only, cubes were present in all cases at low initial concentrations. In contrast, at high concentrations spherical particles precipitated at all three temperatures at the beginning of the reaction. Spherical particles were made up from smaller particles. Over time, the size of the particles was diminishing due to their disintegration into

  18. Determination of Ethyl Carbamate in Alcoholic Beverages and Fermented Foods Sold in Korea.

    Ryu, Dayeon; Choi, Bogyoung; Kim, Eunjoo; Park, Seri; Paeng, Hwijin; Kim, Cho-Il; Lee, Jee-Yeon; Yoon, Hae Jung; Koh, Eunmi

    2015-09-01

    Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were divided into four matrices such as apple juice, milk, Soju (liquor containing about 20% alcohol), and rice porridge. The maximum EC value of 151.06 µg/kg was found in Maesilju (liquor made from Maesil and Soju). Whisky and Bokbunjaju (Korean black raspberry wine) contained 9.90 µg/kg and 6.30 µg/kg, respectively. EC was not detected in other alcoholic beverages. Of 20 fermented foods, Japanese-style soy sauce had highest level of 15.59 µg/kg and traditional one contained 4.18 µg/kg. Soybean paste had 1.18 µg/kg, however, EC was not found in other fermented foods. PMID:26483888

  19. Comparative voltammetric study and determination of carbamate pesticide residues in soil at carbon nanotubes paste electrodes

    THOMMANDRU RAVEENDRANATH BAB

    2014-02-01

    Full Text Available In this investigation, the persistence of carbamate pesticides in soil samples was investigated. A simple and selective differential pulse adsorptive stripping voltammetry was selected for this investigation. Carbon nanotubes paste electrodes were used as working electrodes for differential pulse adsorptive stripping voltammetry and cyclic voltammetry. A symmetric study of the various operational parameters that affect the stripping response was carried out by differential pulse voltammetry. Peak currents were linear over the concentration range of 10-5 to 10-10 M with an accumulation potential of -0.6 V and a 70 s accumulation time with lower detection limits of 1.09 x 10-7 M, 1.07 × 10-7M, 1.09×10-7 M for chlorphropham, thiodicarb, aldicarb. The relative standard deviation (n=10 and correlation coefficient values were 1.15 %, 0.988; 1.13 %, 0.978; and 1.14 %, 0.987, respectively. Universal buffer with pH range 2.0 - 6.0 was used as sup­porting electrolyte. The solutions with uniform concentration (10-5 M were used in all deter­minations. Calculations were made by standard addition method.

  20. Cyanate as an Active Precursor of Ethyl Carbamate Formation in Sugar Cane Spirit.

    Galinaro, Carlos A; Ohe, Thiago H K; da Silva, Augusto C H; da Silva, Sebastião C; Franco, Douglas W

    2015-08-26

    The thermodynamic and kinetic aspects of ethyl carbamate (EC) formation through the reaction between cyanate and ethanol were investigated. The rate constant values for cyanate ion decay and EC formation are (8.0 ± 0.4) × 10(-5) and (8.9 ± 0.4) × 10(-5) s(-1), respectively, at 25 °C in 48% aqueous ethanolic solution at pH 4.5. Under the investigated experimental conditions, the rate constants are independent of the ethanol and cyanate concentrations but increase as the temperature increases (ΔH1(⧧) = 19.4 ± 1 kcal/mol, ΔS1(⧧) = −12.1 ± 1 cal/K, and ΔG1(⧧) = 23.0 ± 1 kcal/mol) and decrease as the solution pH increases. According to molecular modeling (DFT) that was performed to analyze the reaction mechanism, the isocyanic acid (HNCO) is the active EC precursor. The calculated ΔG1(⧧), ΔH1(⧧), and ΔS1(⧧) values are in very good agreement with the experimental ones. PMID:26248556

  1. Surface display of recombinant Drosophila melanogaster acetylcholinesterase for detection of organic phosphorus and carbamate pesticides.

    Jingquan Li

    Full Text Available Acetylcholinesterase (AChE is commonly used for the detection of organophosphate (OP and carbamate (CB insecticides. However, the cost of this commercially available enzyme is high, making high-throughput insecticide detection improbable. In this study we constructed a new AChE yeast expression system in Saccharomyces cerevisiae for the expression of a highly reactive recombinant AChE originating from Drosophila melanogaster (DmAChE. Specifically, the coding sequence of DmAChE was fused with the 3'-terminal half of an α-agglutinin anchor region, along with an antigen tag for the detection of the recombinant protein. The target sequence was cloned into the yeast expression vector pYes-DEST52, and the signal peptide sequence was replaced with a glucoamylase secretion region for induced expression. The resultant engineered vector was transformed into S. cerevisiae. DmAChE was expressed and displayed on the cell surface after galactose induction. Our results showed that the recombinant protein displayed activity comparable to the commercial enzyme. We also detected different types of OP and CB insecticides through enzyme inhibition assays, with the expressed DmAChE showing high sensitivity. These results show the construction of a new yeast expression system for DmAChE, which can subsequently be used for detecting OP and CB insecticides with reduced economic costs.

  2. Vibrational spectra and normal coordinate analysis of 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate

    Muthu, S.; Renuga, S.

    2014-11-01

    In this work, the vibrational spectral analysis was carried out by using FT-Raman and FTIR spectroscopy in the range 50-4000 cm-1 and 450-4000 cm-1 respectively, for 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate (2H3MPPLC) molecule. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6-31G(d,p) basis set. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule. The dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the investigated molecule has been computed using B3LYP/6-31G(d,p) method. Mulliken population analysis on atomic charges was also calculated. Besides, frontier molecular orbitals, molecular electrostatic potential (MEP) and thermodynamic properties were performed.

  3. Identification of Novel Steroidal Androgen Receptor Degrading Agents Inspired by Galeterone 3β-Imidazole Carbamate.

    Purushottamachar, Puranik; Kwegyir-Afful, Andrew K; Martin, Marlena S; Ramamurthy, Vidya P; Ramalingam, Senthilmurugan; Njar, Vincent C O

    2016-07-14

    Degradation of all forms of androgen receptors (ARs) is emerging as an advantageous therapeutic paradigm for the effective treatment of prostate cancer. In continuation of our program to identify and develop improved efficacious novel small-molecule agents designed to disrupt AR signaling through enhanced AR degradation, we have designed, synthesized, and evaluated novel C-3 modified analogues of our phase 3 clinical agent, galeterone (5). Concerns of potential in vivo stability of our recently discovered more efficacious galeterone 3β-imidazole carbamate (6) led to the design and synthesis of new steroidal compounds. Two of the 11 compounds, 3β-pyridyl ether (8) and 3β-imidazole (17) with antiproliferative GI50 values of 3.24 and 2.54 μM against CWR22Rv1 prostate cancer cell, are 2.75- and 3.5-fold superior to 5. In addition, compounds 8 and 17 possess improved (∼4-fold) AR-V7 degrading activities. Importantly, these two compounds are expected to be metabolically stable, making them suitable for further development as new therapeutics against all forms of prostate cancer. PMID:27437082

  4. Reduced production of ethyl carbamate for wine fermentation by deleting CAR1 in Saccharomyces cerevisiae.

    Guo, Xue-Wu; Li, Yuan-Zi; Guo, Jian; Wang, Qing; Huang, Shi-Yong; Chen, Ye-Fu; Du, Li-Ping; Xiao, Dong-Guang

    2016-05-01

    Ethyl carbamate (EC), a pluripotent carcinogen, is mainly formed by a spontaneous chemical reaction of ethanol with urea in wine. The arginine, one of the major amino acids in grape musts, is metabolized by arginase (encoded by CAR1) to ornithine and urea. To reduce the production of urea and EC, an arginase-deficient recombinant strain YZ22 (Δcarl/Δcarl) was constructed from a diploid wine yeast, WY1, by successive deletion of two CAR1 alleles to block the pathway of urea production. The RT-qPCR results indicated that the YZ22 almost did not express CAR1 gene and the specific arginase activity of strain YZ22 was 12.64 times lower than that of parent strain WY1. The fermentation results showed that the content of urea and EC in wine decreased by 77.89 and 73.78 %, respectively. Furthermore, EC was forming in a much lower speed with the lower urea during wine storage. Moreover, the two CAR1 allele deletion strain YZ22 was substantially equivalent to parental strain in terms of growth and fermentation characteristics. Our research also suggested that EC in wine originates mainly from urea that is produced by the arginine. PMID:26831650

  5. Validation of analytical methods for ethyl carbamate in nine food matrices.

    Ryu, Dayeon; Choi, Bogyoung; Kim, Nayoung; Koh, Eunmi

    2016-11-15

    Ethyl carbamate (EC) is formed through a reaction between ethanol and either cyanate or N-carbamyl compounds. This study aimed to develop and validate analytical methods for EC determination in nine food matrices: apple juice, soju, milk, corn oil, rice porridge, peanut butter, beef, flat fish, and sea mustard. Differences from AOAC procedure were use of d5-EC as internal standard, dilution of alcohol content, removal of lipophilic compounds by hexane, and removal of hydrophilic polysaccharides by gel-forming. Standard curves had a good linearity (R(2)>0.997) in all matrices tested. LOD and LOQ were in the range of 0.69-6.08μg/kg and 2.10-18.43μg/kg, respectively. Recovery rates ranged from 80.75 to 121.82% for intra-day and ranged from 78.84 to 116.98% for inter-day. The relative standard deviations (RSDs) were below 14%. These results indicate that the established methods can be applied to determine EC in a variety of foods. PMID:27283695

  6. Zum thermischen Verhalten einiger Kohlensäure[(methylphenylsilyl)methyl]ester-Derivate

    Tacke, Reinhold; Link, Matthias; Bentlage-Felten, Anke; Zilch, Harald

    2016-01-01

    The synthesis and the thermal behaviour of the (methylphenylsilyl)methyl carbonates \\(CH_3(C_6H_5)Si(H)CH_2OC(O)X (6: X = OCH_3; 7: X = Cl; 8: X = N(CH_3)_2)\\) is described. 8 rearranges in toluene solution at 100 °C quantitatively to give the carbam oyloxysilane \\(C_6H_5(CH_3)_2SiOC(O)N(CH_3)_2\\) (11), whereas neat 6 and 7 at 135 °C undergo quantitative formation of \\(C_6H_5(CH_3)_2SiOCH_3\\) (12) and \\(C_6H_5(CH_3)_2SiCl\\) (13), respectively. The formation of 12 and 13 is explained by a rear...

  7. Lysine methylation: beyond histones

    Xi Zhang; Hong Wen; Xiaobing Shi

    2012-01-01

    Posttranslational modifications (PTMs) of histone proteins,such as acetylation,methylation,phosphorylation,and ubiquitylation,play essential roles in regulating chromatin dynamics.Combinations of different modifications on the histone proteins,termed 'histone code' in many cases,extend the information potential of the genetic code by regulating DNA at the epigenetic level.Many PTMs occur on non-histone proteins as well as histones,regulating protein-protein interactions,stability,localization,and/or enzymatic activities of proteins involved in diverse cellular processes.Although protein phosphorylation,ubiquitylation,and acetylation have been extensively studied,only a few proteins other than histones have been reported that can be modified by lysine methylation.This review summarizes the current progress on lysine methylation of nonhistone proteins,and we propose that lysine methylation,like phosphorylation and acetylation,is a common PTM that regulates proteins in diverse cellular processes.

  8. Methylated DNA in Borrelia species.

    Hughes, C A; Johnson, R C

    1990-01-01

    The DNA of Borrelia species was examined for the presence of methylated GATC sequences. The relapsing-fever Borrelia sp., B. coriaceae, and only 3 of 22 strains of B. burgdorferi contained adenine methylation systems. B. anserina lacked an adenine methylation system. Fundamental differences in DNA methylation exist among members of the genus Borrelia.

  9. Inheritance of Cytosine Methylation.

    Tillo, Desiree; Mukherjee, Sanjit; Vinson, Charles

    2016-11-01

    There are numerous examples of parental transgenerational inheritance that is epigenetic. The informational molecules include RNA, chromatin modifications, and cytosine methylation. With advances in DNA sequencing technologies, the molecular and epigenetic mechanisms mediating these effects are now starting to be uncovered. This mini-review will highlight some of the examples of epigenetic inheritance, the establishment of cytosine methylation in sperm, and recent genomic studies linking sperm cytosine methylation to epigenetic effects on offspring. A recent paper examining changes in diet and sperm cytosine methylation from pools of eight animals each, found differences between a normal diet, a high fat diet, and a low protein diet. However, epivariation between individuals within a group was greater than the differences between groups obscuring any potential methylation changes linked to diet. Learning more about epivariation may help unravel the mechanisms that regulate cytosine methylation. In addition, other experimental and genetic systems may also produce more dramatic changes in the sperm methylome, making it easier to unravel potential transgenerational phenomena. J. Cell. Physiol. 231: 2346-2352, 2016. © 2016 Wiley Periodicals, Inc. PMID:26910768

  10. Ethyl carbamate in cachaça (Brazilian sugarcane spirit): Extended survey confirms simple mitigation approaches in pot still distillation.

    Nóbrega, Ian C C; Pereira, José A P; Paiva, José E; Lachenmeier, Dirk W

    2011-08-01

    In 2009, we reported an association between low levels of ethyl carbamate (EC) in pot still cachaças from Paraíba State, Brazil, and distillation in copper pot stills equipped with cooled columns. To strengthen these observations, we extended our study to Pernambuco State and assessed 13 pot still and 20 column still cachaça brands. An EC range from distillation apparatus. Maximising distillation reflux ratios in the ascending parts and minimising exposure to copper in the descending parts (through the use of stainless steel) can reduce EC, and also avoid copper contamination. PMID:25214121

  11. tert-Butyl N-[2-(N-isobutyl-4-meth-oxy-benzene-sulfonamido)-eth-yl]carbamate.

    Bai, Xiao-Guang; Wang, Ju-Xian

    2014-06-01

    The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso-butyl-amino)-ethyl-carbamate with p-meth-oxy-phenyl-sulfonyl chloride. In the mol-ecule, two intra-molecular C-H⋯O hydrogen bonds are observed. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C-H⋯O hydrogen bonds, forming layers parallel to the bc plane. PMID:24940254

  12. Synthesis and antimicrobial activities of new oxime carbamates of 3-aryl-2-thioquinazolin-4(3H)-one

    Suresh S Patil; Swati D Jadhav; M B Deshmukh

    2012-09-01

    S-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one (1) with chloroacetone gave 2-(propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding oxime carbamates 4. The synthesized compounds have been confirmed using IR and 1H NMR, mass spectral data together with elemental analysis. All newly synthesized compounds have been tested for their antibacterial and antifungal activities.

  13. Onsager heat of transport of carbon dioxide at the surface of aqueous ammonia: The remarkable effect of carbamate formation

    Packwood, Daniel M.; Phillips, Leon F.

    2010-11-01

    The Onsager heat of transport Q∗ has been measured for CO 2 at the surface of aqueous ammonia. The heat of transport incorporates the enthalpy of reaction of gaseous CO 2 with ammonia, adsorbed on the liquid surface, to form adsorbed ammonium carbamate, with the result that -Q∗ has the unusually large value of 180 kJ mol -1. Measurement of Q∗ for transfer of a reactive species through a surfactant monolayer is proposed as a new method of studying reactions at liquid and quasi-liquid surfaces.

  14. 酒中氨基甲酸乙酯的研究%Research Advancement of Ethyl Carbamate in Liquor

    张瑞雨; 梁孟军; 李旭

    2014-01-01

    The mechanism,jeopardy,analysis method of ethyl carbamate(EC) was summarized as a carcinogen for public health.The limitation standard of EC was proposed to be established.%本文对酒中氨基甲酸乙酯的形成机制、危害、检测方法进行了综述,引起社会对这种致癌物质的认识和关注,倡导建立氨基甲酸乙酯的限量标准。

  15. tert-Butyl N-[6-(N,N-dipropylcarbamoyl-1,3-benzothiazol-2-yl]carbamate

    Xin Fang

    2010-05-01

    Full Text Available The title compound C19H27N3O3S, crystallizes with two unique molecules in the asymmetric unit. The benzene ring of each benzothiazole unit carries a dipropylcarbamoyl substituent in the 6-position and a tert-butyl carbamate unit on each thiazole ring. In the crystal structure, intermolecular N—H...N and weak C—H...O hydrogen bonds form centrosymmetric dimers. Additional C—H...O contacts construct a three-dimensional network. A very weak C—H...π contact is also present.

  16. An evaluation of ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) for anthelmintic activity in domestic animals.

    Panitz, E

    1977-03-01

    Ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens. Sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. At 15 mg/kg, efficacy against adult and larval Oxyuris equi was 100% and 91% and against small strongyles it was 98%. Efficacy levels were 95% against Strongylus vulgaris and S. edentatus at the 20 mg/kg dosage. In two trials at 100 mg/kg efficacy against Parascaris equorum was 77%. No efficacy was observed against Gastrophilus spp. or Anoplocephala spp. In swine single oral doses of 10 to 100 mg/kg were not effective. 500 ppm Sch 18099 in the diet for seven days resulted in 100% efficacy against Ascaris suum and Trichuris suis but had no effect on Stongyloides ransomi. Efficacy at 250 ppm against A. suum was 77%. Efficacy at 200 mg/kg in lambs was greater than 90% for Haemonchus contortus, Trichostrongylus axei, Marshallagia marshalli, Bunostomum trignocephalum, Oesophagostomum columbianum, Trichuris ovis, and Chabertia spp. Efficacy was less than 80% for Trichostrongylus vitrinus, Nematodirus filicollis, Ostertagia circumcinta and Cooperia curticei. Except for O. circumcinta and C. curticei, drug efficacy was reduced for these worms in lambs treated at 100 mg/kg. Efficacies of 14.3-89% against Ascaridia galli were obtained with dietary levels of 125-1000 ppm Sch 18099 fed for 7 days. Efficacy of 100% was recorded against Heterakis gallinarum at the 1000 ppm dietary drug level. PMID:864223

  17. Vibrational spectra study of phosphorus dendrimer containing azobenzene, ammonium and carbamate groups

    Furer, V. L.; Vandyukov, A. E.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2013-06-01

    The FTIR and FT Raman spectra of the first generation dendrimers, possessing carbamate (G1) or ammonium (G2) terminal groups were studied. The structural optimization and normal mode analysis were performed for dendrimers on the basis of the density functional theory (DFT). These calculations of G2 gave the frequencies of vibrations, infrared intensities and Raman scattering activities for the E- and Z-forms of azobenzene unit. The energy difference between the E- and Z-forms of G2 is 27.36 kcal/mol. The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that dendrimers molecules have a concave lens structure with planar -O-C6H4-CHdbnd N-N(CH3)Pdbnd S, and -O-C6H4-Ndbnd N-C6H4-CHdbnd N-NH-Cdbnd O-CH2-N fragments and slightly non-planar cyclotriphosphazene core. The experimental IR and Raman spectra of dendrimers G1 and G2 were interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The strong band 1605 cm-1 in the IR spectra show marked changes of the optical density in dependence of substituents in the aromatic ring. The differences in the IR and Raman spectra of G2 for the E- and Z-forms of azobenzene units were cleared up. During structural isomerization of azobenzene units, redistribution of band intensities appears to a much higher extent than frequency shifts.

  18. Effects of organophosphate,carbamate and pyrethroid insecticides and their mixtures on neuromuscular junction transmission

    HeFS; XiaoC

    2002-01-01

    To investigate the effects of organophosphorus (OP),carbamate (Carb),pyrehroid (Pyr) insecticides and their mixtures on neuromuscular junction transmission (NMJT),dimethoate(D) and phoxim(P),methomyl(M),and fenvalerate(F) were selected.Rats were intraperitoneally intoxicated by D,P,M,F,D+M,D+F,P+M,or P+F with the dosage of each LD50 respectively.The function of the NMJT was assessed with the mean consecutive differences (MCD) of the latencies of single fiber action potentials detected by stimulation single fiber electromyography(SSFEMG) at the stimulus frequency of 20 Hz.The SSFEMG was also applied to detect the function of NMJT in 40 patients with OPs and their mixtures poisoning in this study.The results showed that (1)the myasthenia occurred only in rats with OPs and their mixtures poisoning,but not in F,M intoxicated rats.The increase of MCD shown by SSFEMG and induced by OP and their mixtures indicating a post-synaptic block was well correlated with the occurrence of myasthenia both in rats and patients(P<0.001);(2)the increase of MCD in rats of OP poisoning was significant in comparison with the control and F,M intoxicated rats;but was not significantly different from those in rats intoxicated by OP mixtures;(3)the MCDs were significantly increased in IMS patients of both acute OP poisoning and OP mixtures poisoning,but showing no significant difference between the two groups of patients.It is concluded that OP is the only responsible agent for the dysfunction of neuromuscular transmission induced by single OP and OP mixture insecticides which could be sensitively detected by SSFEMG.

  19. Detection of Methomyl, a Carbamate Insecticide, in Food Matrices Using Terahertz Time-Domain Spectroscopy

    Baek, Seung Hyun; Kang, Ju Hee; Hwang, Yeun Hee; Ok, Kang Min; Kwak, Kyungwon; Chun, Hyang Sook

    2016-05-01

    The aim of this study was to investigate the feasibility of detecting methomyl, a carbamate insecticide, in food matrices (wheat and rice flours) using terahertz time-domain spectroscopy (THz-TDS). In the frequency range 0.1-3 THz, the characteristic THz absorption peaks of methomyl at room temperature were detected at 1 (33.4 cm-1), 1.64 (54.7 cm-1), and 1.89 (63.0 cm-1) THz. For detailed spectral analysis, the vibrational frequency and intensity of methomyl were calculated using solid-state density functional theory to mimic molecular interactions in the solid state. Qualitatively, the simulated spectrum was in good agreement with the experimental spectrum. Analysis of the individual absorption modes revealed that all of the features in the THz spectrum of methomyl were mainly generated from intermolecular vibrations. The peak appearing at 1 THz (33.4 cm-1) was then selected and tested for its suitability as a fingerprint for detecting methomyl in food matrices. Its absorbance was dose-dependently distinguishable from that of wheat and rice flours. The calibration curve of methomyl had a regression coefficient of >0.974 and a detection limit of <3.74 %. Accuracy and precision expressed as recovery and relative standard deviation in interday repeatability were in the ranges 78.0-96.5 and 2.83-4.98 %, respectively. Our results suggest that THz-TDS can be used for the rapid detection of methomyl in foods, but its sensitivity needs to be improved.

  20. High lethality and minimal variation after acute self-poisoning with carbamate insecticides in Sri Lanka – implications for global suicide prevention

    Lamb, Thomas; Selvarajah, Liza R.; Mohamed, Fahim; Jayamanne, Shaluka; Gawarammana, Indika; Mostafa, Ahmed; Buckley, Nicholas A.; Roberts, Michael S.; Eddleston, Michael

    2016-01-01

    Abstract Background: Highly hazardous organophosphorus (OP) insecticides are responsible for most pesticide poisoning deaths. As they are removed from agricultural practice, they are often replaced by carbamate insecticides of perceived lower toxicity. However, relatively little is known about poisoning with these insecticides. Methods: We prospectively studied 1288 patients self-poisoned with carbamate insecticides admitted to six Sri Lankan hospitals. Clinical outcomes were recorded for each patient and plasma carbamate concentration measured in a sample to confirm the carbamate ingested. Findings: Patients had ingested 3% carbofuran powder (719), carbosulfan EC25 liquid (25% w/v, 389), or fenobucarb EC50 liquid (50% w/v, 127) formulations, carbamate insecticides of WHO Toxicity Classes Ib, II, and II, respectively. Intubation and ventilation was required for 183 (14.2%) patients while 71 (5.5%) died. Compared with carbofuran, poisoning with carbosulfan or fenobucarb was associated with significantly higher risk of death [carbofuran 2.2%; carbosulfan 11.1%, OR 5.5 (95% CI 3.0–9.8); fenobucarb 6.3%, OR 3.0 (1.2–7.1)] and intubation [carbofuran 6.1%; carbosulfan 27.0%, OR 5.7 (3.9–8.3); fenobucarb 18.9%, OR 3.6 (2.1–6.1)]. The clinical presentation and cause of death did not differ markedly between carbamates. Median time to death was similar: carbofuran 42.3 h (IQR 5.5–67.3), carbosulfan 21.3 h (11.5–71.3), and fenobucarb 25.3 h (17.3–72.1) (p = 0.99); no patients showed delayed onset of toxicity akin to the intermediate syndrome seen after OP insecticide poisoning. For survivors, median duration of intubation was 67.8 h (IQR 27.5–118.8) with no difference in duration between carbamates. Reduced GCS at presentation was associated with worse outcome although some patients with carbosulfan died after presentation with normal GCS. Conclusions: We did not find carbamate insecticide self-poisoning to vary markedly according to the carbamate

  1. 固相膜萃取-高效液相色谱法测定饮用水中12种氨基甲酸酯类农药残留%Determination of twelve carbamate residues in drinking water by HPLC after solid-phase membrane extraction

    杨晓松; 余辉菊; 马子元

    2012-01-01

    目的:建立固相膜萃取-高效液相色谱法测定饮用水中灭多威、涕灭威、速灭威、残灭威、呋喃丹、甲萘威、抗杀虫威、异丙威、硫双威、仲丁威、猛杀威、杀虫威等12种氨基甲酸酯类农药残留量的方法.方法:水样经C18固相萃取膜真空抽滤,滤膜用乙酸乙酯洗脱,洗脱液经氮吹、甲醇溶解,高效液相色谱法测定.结果:12种氨基甲酸酯类农药的线性范围为0.05 mg/L~25.0 mg/L,线性相关系数大于0.999,检出限为0.31 mg/L~1.25 mg/L,水样中氨基甲酸酯类农残最低检测浓度范围为0.005 mg/L~0.019 mg/L,加标回收率为59.3%~97.3%,RSD<7.5%.结论:本方法样品前处理方便、快捷,有机试剂用量少.%Objective:To establish a method for determination of 12 carbamate residues including methomyl, al-dicarb, metolcarb, profluoralin, furadan, methyl carbamate, pirimicarb, isoprocarb, thiodicarb, fenobucarb, promecarb and tetrachlorvinphose in drinking - water by high performance liquid chromatography after solid - phase membrane extraction. Methods: The water sample was filtered through the conditioned solid - phase membrane under vacuum. The carbamales absorbed on the membrane were eluted using ethyl acetate and the eluted solution was blown to dryness under nitrogen gas. The residue was reconstituted with methanol and analyzed by HPLC. Results: The linear range of 12 carbamates residues were between 0. 05 mg/L to 25. 0 mg/L with r >0. 999. The detection limits were 0. 31 mg/L to 1.25 mg/L. The lowest detection limits of carbamate residues in the sample water were between 0.005 mg/L and 0.019 mg/L. The recoveries ranged from 59. 3% to 97. 3% with RSD <7.5% . Conclusion: The method can be used for the multi -residue analysis of carbamate residues in drinking water.

  2. Optimization and validation of liquid-liquid extraction with low temperature partitioning for determination of carbamates in water

    Using a 23 experimental design, liquid-liquid extraction with low temperature partitioning (LLE-LTP) was optimized and validated for analysis of three carbamates (aldicarb, carbofuran and carbaryl) in water samples. In this method, 2.0 mL of sample is placed in contact with 4.0 mL of acetonitrile. After agitation, the sample is placed in a freezer for 3 h for phase separation. The organic extract is analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). For validation of the technique, the following figures of merit were evaluated: accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity. Extraction recovery percentages of the carbamates aldicarb, carbofuran and carbaryl were 90%, 95% and 96%, respectively. Even though extremely low volumes of sample and solvent were used, the extraction method was selective and the detection and quantification limits were between 5.0 and 10.0 μg L-1, and 17.0 and 33.0 μg L-1, respectively.

  3. Vibrational spectra study of fluorescent dendrimers built from the cyclotriphosphazene core with terminal dansyl and carbamate groups

    Furer, V. L.; Vandyukova, I. I.; Vandyukov, A. E.; Fuchs, S.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2011-08-01

    The FTIR and FT Raman spectra of the "Janus"-type dendrimers, possessing five carbamate groups on one side and five fluorescent dansyl derivatives on the other side, with amide G1 and hydrazone G2 central linkages were studied. These surface-block dendrimers are obtained by the coupling of two different dendrons. The FTIR and FT-Raman spectra of the zero generation dendrons, built from the hexafunctional cyclotriphosphazene core, with five dansyl terminal groups and one carbamate G0 v and one oxybenzaldehyde function G0v have been recorded. The structural optimization and normal mode analysis were performed for dendron G0v on the basis of the density functional theory (DFT). The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that dendron molecule G0v has a concave lens structure with planar -O-C6H4-CHdbnd O fragments and slightly non-planar cyclotriphosphazene core. The experimental IR and Raman spectra of dendron G0v were interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The strong band 1597 cm -1 show marked changes of the optical density in dependence of substituents in the aromatic ring. The frequencies of ν(N-H) bands in the IR spectra reveal the presence of the different types of H-bonds in the dendrimers.

  4. [DNA methylation in obesity].

    Pokrywka, Małgorzata; Kieć-Wilk, Beata; Polus, Anna; Wybrańska, Iwona

    2014-01-01

    The number of overweight and obese people is increasing at an alarming rate, especially in the developed and developing countries. Obesity is a major risk factor for diabetes, cardiovascular disease, and cancer, and in consequence for premature death. The development of obesity results from the interplay of both genetic and environmental factors, which include sedentary life style and abnormal eating habits. In the past few years a number of events accompanying obesity, affecting expression of genes which are not directly connected with the DNA base sequence (e.g. epigenetic changes), have been described. Epigenetic processes include DNA methylation, histone modifications such as acetylation, methylation, phosphorylation, ubiquitination, and sumoylation, as well as non-coding micro-RNA (miRNA) synthesis. In this review, the known changes in the profile of DNA methylation as a factor affecting obesity and its complications are described. PMID:25531701

  5. Apoptosis and DNA Methylation

    Richard R. Meehan

    2011-04-01

    Full Text Available Epigenetic mechanisms assist in maintaining gene expression patterns and cellular properties in developing and adult tissues. The molecular pathology of disease states frequently includes perturbation of DNA and histone methylation patterns, which can activate apoptotic pathways associated with maintenance of genome integrity. This perspective focuses on the pathways linking DNA methyltransferases and methyl-CpG binding proteins to apoptosis, and includes new bioinformatic analyses to characterize the evolutionary origin of two G/T mismatch-specific thymine DNA glycosylases, MBD4 and TDG.

  6. Catalytic aziridination of electron-deficient olefins with an N-chloro-N-sodio carbamate and application of this novel method to asymmetric synthesis.

    Minakata, Satoshi; Murakami, Yuta; Tsuruoka, Ryoji; Kitanaka, Shinsuke; Komatsu, Mitsuo

    2008-12-21

    A new method for the aziridination of electron-deficient olefins using an N-chloro-N-sodio carbamate is described; the reaction was promoted by phase-transfer catalysis (solid-liquid) and afforded aziridines from alpha,beta-unsaturated ketones, esters, sulfones and amides. PMID:19048156

  7. Is the carbamate juvenoid W-328 an insect growth regulator for the cockroach .I.Blaberus craniifer./I. Br. (Insecta, Dictyoptera)?

    Goudey-Perriere, F.; Lemonnier, F.; Perriere, C.; Dahmani, F. Z.; Wimmer, Zdeněk

    2003-01-01

    Roč. 75, - (2003), s. 47-59. ISSN 0048-3575 Institutional research plan: CEZ:AV0Z4055905 Keywords : Blaberus craniifer * Blattella germanica * carbamate juvenoids Subject RIV: CC - Organic Chemistry Impact factor: 0.768, year: 2003

  8. Development of a strategy for the asymmetric synthesis of polycyclic polyprenylated acylphloroglucinols via N-amino cyclic carbamate hydrazones: application to the total synthesis of (+)-clusianone.

    Garnsey, Michelle R; Lim, Daniel; Yost, Julianne M; Coltart, Don M

    2010-11-19

    A broadly applicable asymmetric synthetic strategy utilizing N-amino cyclic carbamate alkylation that provides access to the various stereochemical permutations of a common structural motif found in many polycyclic polyprenylated acylphloroglucinols is described. The utility of this methodology is demonstrated through the first asymmetric total synthesis of the antiviral agent (+)-clusianone. PMID:20977254

  9. Ferric chloride-catalyzed reaction of [60]fullerene with tert-butyl N-substituted carbamates: synthesis of oxazolidino[4,5:1,2][60]fullerenes.

    You, Xun; Wang, Guan-Wu

    2014-01-01

    The rare oxazolidinofullerenes have been prepared by the ferric chloride-catalyzed reaction of [60]fullerene with various tert-butyl N-substituted carbamates via t-Bu-O bond cleavage and heteroannulation under mild conditions. A possible mechanism for the formation of oxazolidinofullerenes is proposed. PMID:24328055

  10. Efficient Cellular Entry of (r-x-r)-Type Carbamate-Plasmid DNA Complexes and Its Implication for Noninvasive Topical DNA Delivery to Skin.

    Vij, Manika; Natarajan, Poornemaa; Yadav, Amit K; Patil, Kiran M; Pandey, Tanuja; Gupta, Nidhi; Santhiya, Deenan; Kumar, Vaijayanti A; Fernandes, Moneesha; Ganguli, Munia

    2016-06-01

    Arginine-rich cell penetrating peptides are powerful tools for in vitro as well as in vivo delivery of a wide plethora of biomolecules. However, presence of consecutive arginine residues leads to enhanced amenability for proteolytic degradation as well as steric hindrances for membrane interactions which compromise its bioavailability. In order to overcome these limitations we previously reported a safe and stable octaarginine based oligomer, i.e., (r-x-r)4-carbamate, where the backbone amide linkages were replaced by carbamate linkages and 6-aminohexanoic acid based spacer moieties were incorporated for better flexibility, hydrophobicity, optimal spacing of guanidinium groups, and protection against proteolytic cleavage; resulting in improved transfection efficiency over its amide counterpart. In the present work we have investigated the mechanism behind this enhanced transfection efficiency and, based on our observations, demonstrate how the synergistic effect of rationalized oligomer designing, complex characteristics, and cell type contributes to overall effective intracellular delivery. Our results indicate that the (r-x-r)4-carbamate-plasmid DNA complexes primarily utilize lipid raft dependent pathway of cellular entry more than other pathways, and this possibly facilitates their increased entry in the lipid raft rich milieu of skin cells. We also emphasize the utility of oligomer (r-x-r)4-carbamate as an efficient carrier for topical delivery of nucleic acids in skin tissue. This carrier can be utilized for safe, efficient, and noninvasive delivery of therapeutically relevant macromolecular hydrophilic cargo like nucleic acids to skin. PMID:27175623

  11. Quantum Chemical Studies on Solvents for Post-Combustion Carbon Dioxide Capture: Calculation of pKa and Carbamate Stability of Disubtituted Piperazines

    Gangarapu, S.; Wierda, G.J.; Marcelis, A.T.M.; Zuilhof, H.

    2014-01-01

    Piperazine is a widely studied solvent for post-combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of CH3, CH2F, CH2OH, CH2NH2, COCH3, and CN groups of 2,5-disubstituted piperazines on the pKa and carbamate stabili

  12. A Mechanism-based 3D-QSAR Approach for Classification and Prediction of Acetylcholinesterase Inhibitory Potency of Organophosphate and Carbamate Analogs

    Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a serine residue in the enzyme active site, and their inhibitory potency depends largely on affinity for the enzyme and the reactivity of the ester. Despite this understandi...

  13. ORALLY ACTIVE CARBAMATE PRODRUGS OF THE SELECTIVE DOPAMINE AGONIST N-0437 - INVIVO ACTIVITIES IN THE 6-OHDA TURNING MODEL AND INVITRO ACTIVITIES

    DENDAAS, [No Value; DEBOER, P; TEPPER, PG; ROLLEMA, H; HORN, AS

    1991-01-01

    The in-vivo activities of eight carbamate prodrugs of the D2-agonist N-0437 were determined by examining the effects of the prodrugs, after their oral administration in rats with unilateral 6-OHDA lesions of the striatum. The resulting contralateral turning was used as an index of the activity of th

  14. DNA Methylation and Cancer Diagnosis

    Jérôme Torrisani

    2013-07-01

    Full Text Available DNA methylation is a major epigenetic modification that is strongly involved in the physiological control of genome expression. DNA methylation patterns are largely modified in cancer cells and can therefore be used to distinguish cancer cells from normal tissues. This review describes the main technologies available for the detection and the discovery of aberrantly methylated DNA patterns. It also presents the different sources of biological samples suitable for DNA methylation studies. We discuss the interest and perspectives on the use of DNA methylation measurements for cancer diagnosis through examples of methylated genes commonly documented in the literature. The discussion leads to our consideration for why DNA methylation is not commonly used in clinical practice through an examination of the main requirements that constitute a reliable biomarker. Finally, we describe the main DNA methylation inhibitors currently used in clinical trials and those that exhibit promising results.

  15. Methylated β-Cyclodextrins

    Schönbeck, Jens Christian Sidney; Westh, Peter; Madsen, Jens Christian;

    2011-01-01

    groups at O2 promote complexation by extending the hydrophobic cavity. Like in the case of 2-hydroxypropylated cyclodextrins, the methyl substituents cause an increased release of ordered water from the hydration shell of the bile salts, resulting in a strong increase in both the enthalpy and the entropy...

  16. Evidence of carbamate resistance in urban populations of Anopheles gambiae s.s. mosquitoes resistant to DDT and deltamethrin insecticides in Lagos, South-Western Nigeria

    Oduola Adedayo O

    2012-06-01

    Full Text Available Abstract Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05 but was significantly higher (P A. gambiae s.s (M form. The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a clear indication that calls for the implementation of

  17. 氨基甲酸酯淀粉浆料的制备及上浆性能%Manufacture and Sizing Performance of Carbamate Starch Size Mixture

    刘志军; 许冬生

    2011-01-01

    探讨氨基甲酸酯淀粉的取代度对氨基甲酸酯淀粉浆料上浆性能的影响.通过改变氧化铵对淀粉的投料比,制备了一系列具有不同变性程度的氨基甲酸酯淀粉,对不同取代度的氨基甲酸酯淀粉浆料的浆液性能及对棉纤维的黏附性能进行了测试.结果表明:当取代度不超过0.053时,随氨基甲酸酯淀粉取代度的提高,浆液黏度降低,热稳定性提高,对棉纤维的黏着力增大.指出:氨基甲酸酯变性有利于改善淀粉对纯棉经纱的上浆性能.%Effect of carbamate starch substitution degree on size mixture property was discussed. Through changing feed ratio of ammonium chloride to starch,a series of carbamate starch with different substitution degree were made. Sizing property of carbamate starch with different substitution degree and adhesion performance to cotton fiber were tested. The result shows when the substitution degree is less 0. 053 and substitution degree of carbamate starch is increasing,sizing viscosity is reduced, the thermal stability is increased, the adhesion to cotton fiber is increased. It is pointed out that sizing property of carbamate starch to pure cotton yarn can be improved.

  18. Event extraction for DNA methylation

    Ohta Tomoko; Pyysalo Sampo; Miwa Makoto; Tsujii Jun’ichi

    2011-01-01

    Abstract Background We consider the task of automatically extracting DNA methylation events from the biomedical domain literature. DNA methylation is a key mechanism of epigenetic control of gene expression and implicated in many cancers, but there has been little study of automatic information extraction for DNA methylation. Results We present an annotation scheme for DNA methylation following the representation of the BioNLP shared task on event extraction, select a set of 200 abstracts inc...

  19. Identification and characterization of 4-methylbenzyl 4-[(pyrimidin-2-ylamino)methyl]piperidine-1-carboxylate, an orally bioavailable, brain penetrant NR2B selective N-methyl-D-aspartate receptor antagonist.

    Liverton, Nigel J; Bednar, Rodney A; Bednar, Bohumil; Butcher, John W; Claiborne, Christopher F; Claremon, David A; Cunningham, Michael; DiLella, Anthony G; Gaul, Stanley L; Libby, Brian E; Lyle, Elizabeth A; Lynch, Joseph J; McCauley, John A; Mosser, Scott D; Nguyen, Kevin T; Stump, Gary L; Sun, Hong; Wang, Hao; Yergey, James; Koblan, Kenneth S

    2007-02-22

    The discovery of a novel series of NR2B subtype selective N-methyl-d-aspartate (NMDA) antagonists is reported. Initial optimization of a high-throughput screening lead afforded an aminopyridine derivative 13 with significant NR2B antagonist potency but limited selectivity over hERG-channel and other off-target activities. Further structure-activity studies on the aminoheterocycle moiety and optimization of the carbamate led to the highly potent 2-aminopyrimidine derivative 20j with a significantly improved off-target activity profile and oral bioavailability in multiple species coupled with good brain penetration. Compound 20j demonstrated efficacy in in vivo rodent models of antinociception, allodynia, and Parkinson's disease. PMID:17249648

  20. Protein methylation in pea chloroplasts

    The methylation of chloroplast proteins has been investigated by incubating intact pea (Pisum sativum) chloroplasts with [3H-methyl]-S-adenosylmethionine. Incubation in the light increases the amount of methylation in both the thylakoid and stromal fractions. Numerous thylakoid proteins serve as substrates for the methyltransfer reactions. Three of these thylakoid proteins are methylated to a significantly greater extent in the light than in the dark. The primary stromal polypeptide methylated is the large subunit of ribulose bisphosphate carboxylase/oxygenase. One other stromal polypeptide is also methylated much more in the light than in the dark. Two distinct types of protein methylation occur. One methylinkage is stable to basic conditions whereas a second type is base labile. The base-stable linkage is indicative of N-methylation of amino acid residues while base-lability is suggestive of carboxymethylation of amino acid residues. Labeling in the light increases the percentage of methylation that is base labile in the thylakoid fraction while no difference is observed in the amount of base-labile methylations in light-labeled and dark-labeled stromal proteins. Also suggestive of carboxymethylation is the detection of volatile [3H]methyl radioactivity which increases during the labeling period and is greater in chloroplasts labeled in the light as opposed to being labeled in the dark; this implies in vivo turnover of the [3H]methyl group

  1. Evaluation of exposure to organophosphate, carbamate, phenoxy acid, and chlorophenol pesticides in pregnant women from 10 Caribbean countries.

    Forde, Martin S; Robertson, Lyndon; Laouan Sidi, Elhadji A; Côté, Suzanne; Gaudreau, Eric; Drescher, Olivia; Ayotte, Pierre

    2015-09-01

    Pesticides are commonly used in tropical regions such as the Caribbean for both household and agricultural purposes. Of particular concern is exposure during pregnancy, as these compounds can cross the placental barrier and interfere with fetal development. The objective of this study was to evaluate exposure of pregnant women residing in 10 Caribbean countries to the following commonly used classes of pesticides in the Caribbean: organophosphates (OPs), carbamates, phenoxy acids, and chlorophenols. Out of 438 urine samples collected, 15 samples were randomly selected from each Caribbean country giving a total of 150 samples. Samples were analyzed for the following metabolites: six OP dialkylphosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP)]; two carbamate metabolites [2-isopropoxyphenol (2-IPP) and carbofuranphenol]; one phenoxy acid 2,4-dichlorophenoxyacetic acid (2,4-D); and five chlorophenols [2,4-dichlorophenol (DCP), 2,5-dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (TCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP)]. OP metabolites were consistently detected in ≥60% of the samples from Antigua and Barbuda, Bermuda, and Jamaica. Of the carbamate metabolites, 2-IPP was detected in seven of the 10 Caribbean countries with a detection frequency around 30%, whereas carbofuranphenol was detected in only one sample. The detection frequency for the phenoxy acid 2,4-D ranged from 20% in Grenada to a maximum of 67% in Belize. Evidence of exposure to chlorophenol pesticides was also established with 2,4-DCP by geometric means ranging from 0.52 μg L(-1) in St Lucia to a maximum of 1.68 μg L(-1) in Bermuda. Several extreme concentrations of 2,5-DCP were detected in four Caribbean countries-Belize (1100 μg L(-1)), Bermuda (870 μg L(-1)), Jamaica (1300 μg L(-1)), and St Kitts and Nevis (1400 μg L(-1

  2. Synthesis, screening for antiacetylcholinesterase activity and binding mode prediction of a new series of [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters

    Zanatta, Nilo; Marchi, Tiago M.; Bonacorso, Helio G.; Martins, Marcos A.P.; Flores, Alex F.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Nucleo de Quimica de Heterociclos]. E-mail: zanatta@base.ufsm.br; Borchhardt, Deise M.; Andricopulo, Adriano D.; Salum, Livia B. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Centro de Biotecnologia Molecular Estrutural. Lab. de Quimica Medicinal e Computacional; Carpes, Adriana D.; Schetinger, Maria R.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Lab. de Enzimologia Toxicologica

    2008-07-01

    A series of nine new [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters (phosphate-carbamate compounds) was obtained through the reaction of (4,4,4-trifluoro-3-hydroxybut-1-yl)-carbamic acid ethyl esters with phosphorus oxychloride followed by the addition of alcohols. The products were characterized by {sup 1}H, {sup 13}C, {sup 31}P, and {sup 19}F NMR spectroscopy, GC-MS, and elemental analysis. All the synthesized compounds were screened for acetylcholinesterase (AChE) inhibitory activity using the Ellman method. All compounds containing phosphate and carbamate pharmacophores in their structures showed enzyme inhibition, being the compound bearing the diethoxy phosphate group (2b) the most active compound. Molecular modeling studies were performed to investigate the detailed interactions between AChE active site and small-molecule inhibitor candidates, providing valuable structural insights into AChE inhibition. (author)

  3. Chiral separation on sulfonated cellulose tris(3,5-dimethylphenyl carbamate)-coated zirconia monolith by capillary electro chromatography

    Sulfonated cellulose tris(3,5-dimethylphenyl carbamate) (SCDMPC)-coated zirconia monolith (ZM) was used as the chiral stationary phase in capillary electro chromatography for separation of enantiomers of ten chiral compounds in acetonitrile (ACN)-phosphate buffer mixtures as the eluent. Influences of the ACN content, buffer concentration and pH on chiral separation have been investigated. Separation data on SCDMPC-ZM have been compared with those on CDMPC-ZM. Resolution factors were better on SCDMPC-ZM than CDMPC-ZM while retention factors were in general shorter on the former than the latter. Best chiral resolutions on SCDMPC-ZM were obtained with the eluent of 50% ACN containing 50 mM phosphate at pH around 4

  4. Ethyl Carbamate in Alcoholic Beverages from Mexico (Tequila, Mezcal, Bacanora, Sotol and Guatemala (Cuxa: Market Survey and Risk Assessment

    Jürgen Rehm

    2009-01-01

    Full Text Available Ethyl carbamate (EC is a recognized genotoxic carcinogen, with widespread occurrence in fermented foods and beverages. No data on its occurrence in alcoholic beverages from Mexico or Central America is available. Samples of agave spirits including tequila, mezcal, bacanora and sotol (n=110, and of the sugarcane spirit cuxa (n=16 were purchased in Mexico and Guatemala, respectively, and analyzed for EC. The incidence of EC contamination was higher in Mexico than in Guatemala, however, concentrations were below international guideline levels (<0.15 mg/L. Risk assessment found the Margin of Exposure (MOE in line with that of European spirits. It is therefore unlikely that EC plays a role in high rates of liver cirrhosis reported in Mexico.

  5. Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo

    Daniel-Mwuambete K.

    2003-12-01

    Full Text Available Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on mebendazole-treated mice, at doses of 25-50 mg/kg. There was a correlation between ED50 and pharmacokinetical parameters of AUC0∞ and Cmax , showing that a significant improvement on solubility affects the in vivo activity of these drugs.

  6. Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo.

    Daniel-Mwuambete, K; Ponce-Gordo, F; Torrado, J; Torrado, S; Cuesta-Bandera, C

    2003-12-01

    Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on mebendazole-treated mice, at doses of 25-50 mg/kg. There was a correlation between ED50 and pharmacokinetical parameters of AUC0-infinity and Cmax, showing that a significant improvement on solubility affects the in vivo activity of these drugs. PMID:14710635

  7. Temperature-induced uptake of CO2 and formation of carbamates in mesocaged silica modified with n-propylamines.

    Bacsik, Zoltán; Atluri, Rambabu; Garcia-Bennett, Alfonso E; Hedin, Niklas

    2010-06-15

    Adsorption-mediated CO(2) separation can reduce the cost of carbon capture and storage. The reduction in cost requires adsorbents with high capacities for CO(2) sorption and high CO(2)-over-N(2) selectivity. Amine-modified sorbents are promising candidates for carbon capture. To investigate the details of CO(2) adsorption in such materials, we studied mesocaged (cubic, Pm3n symmetry) silica adsorbents with tethered propylamines using Fourier transform infrared (FTIR) spectroscopy and volumetric uptake experiments. The degree of heterogeneity in these coatings was varied by either cosynthesizing or postsynthetically introducing the propylamine modification. In situ FTIR spectroscopy revealed the presence of both physisorbed and chemisorbed CO(2) in the materials. We present direct molecular evidence for physisorption using FTIR spectroscopy in mesoporous silica sorbents modified with propylamines. Physisorption reduced the CO(2)-over-N(2) selectivity in amine-rich sorbents. Samples with homogeneous coatings showed typical CO(2) adsorption trends and large quantities of IR-observable physisorbed CO(2). The uptake of CO(2) in mesocaged materials with heterogeneous propylamine coatings was higher at high temperatures than at low temperatures. At higher temperatures and low pressures, the postsynthetically modified materials adsorbed more CO(2) than did the extracted ones, even though the surface area after modification was clearly reduced and the coverage of primary amine groups was lower. The principal mode of CO(2) uptake in postsynthetically modified mesoporous silica was chemisorption. The chemisorbed moieties were present mainly as carbamate-ammonium ion pairs, resulting from the quantitative transformation of primary amine groups during CO(2) adsorption as established by NIR spectroscopy. The heterogeneity in the coatings promoted the formation of these ion pairs. The average propylamine-propylamine distance must be small to allow the formation of carbamate

  8. Methylation in hepatocellular carcinoma

    Regina M. Santella

    2007-02-01

    Full Text Available

    The development of HCC is a complex, multistep, multistage process. The molecular pathogenesis of HCC appears to involve multiple genetic aberrations in the molecular control of hepatocyte proliferation, differentiation and death and the maintenance of genomic integrity. This process is influenced by the cumulative activation and inactivation of oncogenes, tumor suppressor genes and other genes. p53, a tumor suppressor gene, is the most frequently mutated gene in human cancers. There is also a striking sequence specific binding and induction of mutations by AFB1 at codon 249 of p53 in HCC.

    Epigenetic alterations are also involved in cancer development and progression. Methylation of promoter CpG islands is associated with inhibition of transcriptional initiation and permanent silencing of downstream genes.

    It is now known that most important tumor suppressor genes are inactivated, not only by mutations and deletions but also by promoter methylation. Several studies indicated that p16, p15, RASSF1A, MGMT, and GSTP1 promoter hypermethylation are prevalent in HCC. In addition, geographic variation in the methylation status of tumor DNA indicates that environmental factors may influence the frequent and concordant degree of hypermethylation in multiple genes in HCC and that epigeneticenvironmental interactions may be involved in hepatocarcinogenesis. We have found significant relationships between promoter methylation and AFB1-DNA adducts confirming the impact of environmental exposures on gene methylation.

    DNA isolated from serum or plasma of cancer patients frequently contains the same genetic and

  9. A potent new class of kappa-receptor agonist: 4-substituted 1-(arylacetyl)-2-[(dialkylamino)methyl]piperazines.

    Naylor, A; Judd, D B; Lloyd, J E; Scopes, D I; Hayes, A G; Birch, P J

    1993-07-23

    The synthesis of 4-substituted 1-(arylacetyl)-2-[(alkylamino)methyl]piperazines (10-22, 26, 27, and 30-33) and their activities as kappa-opioid receptor agonists are described. This includes a range of 4-acyl and 4-carboalkoxy derivatives with the latter series showing the greatest kappa-agonist activity. In particular, methyl 4-[(3,4-dichlorophenyl)acetyl]-3-[(1-pyrrolidinyl) methyl]-1-piperazinecarboxylate (18) displays exceptional potency and selectivity. It showed the following activities in functional in vitro assays: rabbit vas deferens (kappa-specific tissue) IC50 = 0.041 nM, rat vas deferens (mu-specific tissue) IC50 > 10,000 nM, and hamster vas deferens (delta-specific tissue) IC50 > 10,000 nM. Compound 18 is also a highly potent antinociceptive agent, as determined in the mouse acetylcholine-induced abdominal constriction test: ED50 = 0.000 52 mg/kg, sc. The activity of 18 resides solely in its 3(R)-enantiomer. The kappa-agonist activity in both the 4-acyl and the 4-carbamate series is sensitive to the size of the 4-substituent. In addition, it would appear that an appreciable negative electrostatic potential in this region of the molecule is an important requirement for optimal potency. PMID:8393489

  10. Vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction for the determination of carbamates in juices by micellar electrokinetic chromatography tandem mass spectrometry.

    Moreno-González, David; Huertas-Pérez, José F; García-Campaña, Ana M; Gámiz-Gracia, Laura

    2015-07-01

    A new method based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction has been developed for the extraction of carbamate pesticides in juice samples prior to their determination by micellar electrokinetic chromatography coupled to tandem mass spectrometry. This sample treatment allowed the satisfactory extraction and the extract clean-up of 25 carbamates from different fruit and vegetal juices (banana, tomato, and peach). In this study, the addition of ammonium perfluorooctanoate in the aqueous sample in combination with vortex agitation, provided very clean extracts with short extraction times. Under optimized conditions, recoveries of the proposed method for these pesticides from fortified juice samples ranged from 81% to 104%, with relative standard deviations lower than 15%. Limits of quantification were between 2.3µgkg(-)(1) and 4.7µgkg(-)(1), showing the high sensitivity of this fast and simple method. PMID:25882424

  11. 49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. 173.193 Section 173.193 Transportation Other Regulations... bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. (a) Bromoacetone must...

  12. Aberrant methylation patterns in cancer

    Hudler, Petra; Videtič, Alja

    2016-01-01

    Epigenetic mechanisms, such as DNA methylation, DNA hydroxymethylation, post-translational modifications (PTMs) of histone proteins affecting nucleosome remodelling, and regulation by small and large non-coding RNAs (ncRNAs) work in concert with cis and trans acting elements to drive appropriate gene expression. Advances in detection methods and development of dedicated platforms and methylation arrays resulted in an explo - sion of information on aberrantly methylated sequences linking devia...

  13. Supercritical fluid extraction for some carbamate insecticides in potatoes samples with HPLC/flourescence determination and HPLC/mass spectrometry confirmation

    Gilvanda Silva Nunes; Santos, Teresa Cristina R.; Damiá Barceló; Alexandre Santos Pimenta; Maria Lúcia Ribeiro

    2002-01-01

    Six supercritical fluid extraction (SFE) methods were tested, by varying the following operational parameters: CO2 pressure, time and temperature of extraction, type and proportion of static modifier, and Hydromatrix®/sample rate into cell. Firstly, insecticide carbamates were extracted from spiked potatoes samples (fortification level of 0,5 mg.Kg-1) by using SPE procedures, and then final extracts were analyzed HPLC/fluorescence. Good performance was observed with SFE methods that operated ...

  14. The carbamate kinase-like carbamoyl phosphate synthetase of the hyperthermophilic archaeon Pyrococcus furiosus, a missing link in the evolution of carbamoyl phosphate biosynthesis

    Durbecq, Virginie; Legrain, Christianne; Roovers, Martine; Piérard, André; Glansdorff, Nicolas

    1997-01-01

    Microbial carbamoyl phosphate synthetases (CPS) use glutamine as nitrogen donor and are composed of two subunits (or domains), one exhibiting glutaminase activity, the other able to synthesize carbamoyl phosphate (CP) from bicarbonate, ATP, and ammonia. The pseudodimeric organization of this synthetase suggested that it has evolved by duplication of a smaller kinase, possibly a carbamate kinase (CK). In contrast to other prokaryotes the hyperthermophilic archaeon Pyrococcus furiosus was found...

  15. 氨基甲酸酯淀粉浆料抗老化性分析%Study on Anti-aging Property of Carbamate Starch Size Mixture

    刘志军

    2013-01-01

    探讨氨基甲酸酯淀粉浆料的抗老化性能.通过改变尿素对玉米淀粉的投料比,制备出一系列具有不同取代度的氨基甲酸酯淀粉,测试了淀粉浆液的黏度、透明度和沉降积,研究了氨基甲酸酯化变性程度与淀粉浆液抗老化性能之间的关系.结果表明:当取代度不超过0.054时,随着氨基甲酸酯化程度的提高,浆液的冷热黏度差值变小,透明度得到明显改善,沉降积增加.指出:当取代度不超过0.054时,氨基甲酸酯淀粉随取代度的提高,浆液的老化速度降低,抗老化性能明显改善.%Anti-aging property of carbamate starch size mixture was studied. A series of carbamate starch with different substitution degrees were prepared through changing the feed ration of urea to native corn starch. The viscosity, transparency and sedimentation volume of starch sizing were measured. The relationship between modification of carbamate starch and anti-aging property of the starch sizing was investigated. The result shows when the substitution degree is less 0.054,as substitution degree of carbamate starch increases,the difference of cold and hot viscosity of starch is reduced, the transparency of the starch is improved,the sedimentation volume of the starch is increased and the anti-aging property is improved significantly.

  16. 一些N-酰基取代(硫代)氨基甲酸酯的合成%The Synthesis of Some N-Acyl Carbamates & Thionocarbamates

    杨光; 司宗兴

    1999-01-01

      合成了9种新的N-酰基取代(硫代)氨基甲酸酯化合物,它们的结构均通过IR、1HNMR及元素分析予以确证。%  Two series of carbamates were synthesized and all compounds were confirmed by 1HNMR , IR and elementary analysis . The synthetic methods and the spectrum properties of new compounds were discussed.

  17. 氨基甲酸酯类农药的微色谱快速检测法%Rapid Determination of Carbamate Pesticides by Micro-chromatography

    卫海燕; 邵华

    2011-01-01

    [ Objective] To rapidly detect the carbamate pesticides by preparing a new instrument of micro-column detector with capillary effect. [ Methods ] Based on the principle of thin-layer chromatography, fixing the sorbent in the thin heating wire, using microcolumn detector to prepare a new instrument of micro-column detector, the carbamate pesticides was rapidly detected and analyzed qualitatively and quantitatively. [ Results ] The method can make qualitative and quantitative analysis of carbamate pesticides, and the minimum detection limit was 50 μg. [ Conclusion ] The method is simple, efficient , reproducible, with less reagent consumption,can be used to detect bulk carbamate pesticides samples and it is a new method for rapid pesticide poisoning filtering.%目的 利用毛细管效应建立制备微色谱柱检测器以快速检测氨基甲酸酯类农药.方法 在薄层色谱原理的基础上,通过将吸着剂固定于细加热丝上,利用毛细管效应制备微色谱柱检测器,对氨基甲酸酯类农药作出快速的定性分析.结果 该方法 可以对氨基甲酸酯类农药作出快速的定性分析,且最低检出量可达到50 μg.结论 该法操作简便,高效,重现性好,且试剂用量少,是批量氨基甲酸酯类农药样品定性检测和突发农药中毒事件现场快速筛选的一种新方法 .

  18. Synthesis of Industrially Relevant Carbamates towards Isocyanates using Carbon Dioxide and Organotin(IV) Alkoxides.

    Germain, Nicolas; Müller, Imke; Hanauer, Matthias; Paciello, Rocco A; Baumann, Robert; Trapp, Oliver; Schaub, Thomas

    2016-07-01

    A straightforward phosgene-free synthesis of aromatic isocyanates and diisocyanates is disclosed. Theoretical investigations suggested that the insertion of carbon dioxide (CO2 ) by dialkyltin(IV) dialkoxides could be used to convert aromatic amines into aromatic mono- and dicarbamates. Here we show, that methyl phenylcarbamate (MPC) from aniline using organotin(IV) dimethoxide and CO2 can be formed in high yield of up to 92 %, experimentally corroborating the predictions of density functional theory (DFT) calculations. MPC was then separated from the tin oxide residues and converted into phenyl isocyanate. Furthermore, organotin(IV) alkoxides could be regenerated from the tin oxide residues and reused, paving the way for a continuous industrial process. Extension of the scope to the synthesis of diurethanes from toluene 2,4-diamine and 4,4'-methylenedianiline could potentially allow the efficient production of industrially relevant diisocyanates. PMID:27319978

  19. Ionic liquid polymer functionalized carbon nanotubes-doped poly(3,4-ethylenedioxythiophene) for highly-efficient solid-phase microextraction of carbamate pesticides.

    Wu, Mian; Wang, Liying; Zeng, Baizhao; Zhao, Faqiong

    2016-04-29

    A poly(3,4-ethylenedioxythiophene)-ionic liquid polymer functionalized multiwalled carbon nanotubes (PEDOT-PIL/MWCNTs) composite solid-phase microextraction (SPME) coating was fabricated by electrodeposition. After being dipped in Nafion solution, a Nafion-modified coating was obtained. The outer layer Nafion played a crucial role in enhancing the durability and stability of the coating, thus it was robust enough for replicated extraction for at least 150 times without decrease of extraction performance. The Nafion-modified coating exhibited much higher sensitivity than commercial coatings for the direct extraction of carbamate pesticides in aqueous solutions, due to its strong hydrophobic effect and π-π affinity based enrichment. When it was used for the determination of carbamate pesticides in combination with gas chromatography-flame ionization detection, good linearity (correlation coefficients higher than 0.9981), low limits of detection (15.2-27.2 ng/L) and satisfactory precision (relative standard deviation <8.2%, n=5) were achieved. The developed method was applied to the analysis of four carbamate pesticides in apple and lettuce samples, and acceptable recoveries (i.e. 87.5-106.5%) were obtained for the standard addition. PMID:27036210

  20. An evaluation of liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization for the rapid and simultaneous measurement of carbamate pesticides and organophorus pesticides

    Liquid chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface (LC/APCI/MS) is evaluated for the simultaneous determination of carbamate pesticides and organophosphorus pesticides in a single chromatographic analysis. APCI mass spectra of those compounds were obtained to study their ionization characteristics. APCI provided abundant ions such as protonated molecules and characteristic fragment ions for carbamate pesticides and organophosphorus pesticides. To evaluate the feasibility of the LC/APCI/MS for a routine quantitative analysis, the linearity and repeatability of LC/APCI/MS were examined by measuring standard solution mixtures of five carbamate pesticides and four organophosphorus pesticides over the range of 1 to 100 μg/mL. The peak areas in chromatograms of characteristic ions for those compounds showed less than 3% of variation from run to tun. The standard calibration curves for the nine pesticides show good linearity in the concentration range. The detection limits of the LC/APCI/MS system for those compounds range from 0.006 to 0.2 ng

  1. DFT study of structure, IR and Raman spectra of the first generation dendron built from cyclotriphosphazene core with terminal carbamate and ester groups

    Furer, V. L.; Vandyukov, A. E.; Fuchs, S.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2012-06-01

    The FTIR and FT-Raman spectra of the first generation dendron built from the cyclotriphosphazene core, five arms sbnd Osbnd C6H4sbnd CHdbnd Nsbnd N(CH3)sbnd P(S)rbond2 with ten carbamate terminal groups and one ester function Gv1 have been recorded. The IR and Raman spectra of the zero generation dendron Gv0 and first generation dendrimer G1 with the same core and terminal groups were also examined. The structural optimization and normal mode analysis were performed for dendron Gv1 on the basis of the density functional theory (DFT). The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that Gv1 has a concave lens structure with planar sbnd Osbnd C6H4sbnd CHdbnd Nsbnd N(CH3)sbnd P(S)rbond2 fragments and slightly non-planar cyclotriphosphazene core. The carbamate groups attached to different arms show significant deviations from a symmetrical arrangement relative to the local planes of repeating units. The experimental IR spectrum of Gv1 dendron was interpreted by means of potential energy distributions. The strong band 1604 cm-1 shows marked changes of the optical density in dependence of the carbamate, ester or azomethyne substituents in the aromatic ring. The frequencies of ν(Nsbnd H) and ν(Cdbnd O) bands in the IR spectra reveal the presence of the different types of H-bonds in the studied dendrimers.

  2. Complex effect of thiadiazole derivatives and carbamate%噻二唑衍生物与氨基甲酸酯复合效应机理研究

    陈化飞; 许玲玲; 刘蕊; 于宁; 宋应金

    2014-01-01

    根据二巯基苯并噻二唑独特的抗高温氧化性能和特有的有色金属腐蚀抑制性能以及二戊基氨基甲酸酯特殊的抗磨性能和特殊的过氧化物的中和性能,对它们的复合进行四球摩擦磨损试验和抗氧化试验研究,并与二烷基二硫代磷酸锌的性能进行对比研究,从中找出替代其的理论依据。%According to unique high temperature oxidation resistance and corrosion inhibition of 2 mercaptobenzothiazole thiadiazole and diamyl carbamate , and unique abrasion resistance and peroxide performance of diamyl carbamate ,the complex effects of 2 mercaptobenzothia-zole thiadiazole and diamyl carbamate were studied .The complex effects were evaluated by four-ball tester and the antioxidant test .Comparing with performance of zinc dialkyl dithio-phosphate ( ZDDP) , the theory basis of alternative was found out .

  3. DNA methylation in metabolic disorders

    Barres, Romain; Zierath, Juleen R

    2011-01-01

    have provided evidence that environmental factors at all ages could modify DNA methylation in somatic tissues, which suggests that DNA methylation is a more dynamic process than previously appreciated. Because of the importance of lifestyle factors in metabolic disorders, DNA methylation provides...... a mechanism by which environmental factors, including diet and exercise, can modify genetic predisposition to disease. This article considers the current evidence that defines a role for DNA methylation in metabolic disorders.......DNA methylation is a major epigenetic modification that controls gene expression in physiologic and pathologic states. Metabolic diseases such as diabetes and obesity are associated with profound alterations in gene expression that are caused by genetic and environmental factors. Recent reports...

  4. Methods of DNA methylation detection

    Maki, Wusi Chen (Inventor); Filanoski, Brian John (Inventor); Mishra, Nirankar (Inventor); Rastogi, Shiva (Inventor)

    2010-01-01

    The present invention provides for methods of DNA methylation detection. The present invention provides for methods of generating and detecting specific electronic signals that report the methylation status of targeted DNA molecules in biological samples.Two methods are described, direct and indirect detection of methylated DNA molecules in a nano transistor based device. In the direct detection, methylated target DNA molecules are captured on the sensing surface resulting in changes in the electrical properties of a nano transistor. These changes generate detectable electronic signals. In the indirect detection, antibody-DNA conjugates are used to identify methylated DNA molecules. RNA signal molecules are generated through an in vitro transcription process. These RNA molecules are captured on the sensing surface change the electrical properties of nano transistor thereby generating detectable electronic signals.

  5. Research of Phosphate-carbamate Amylose Sizing Property%磷酸-氨基甲酸酯直链淀粉浆液性能研究

    闫怀义; 贺丽丽

    2012-01-01

    Sizing property of phosphate-carbamate amylose was discussed. Phosphate-carbamate amylose, phosphate amylose and phosphate starch were prepared. Through contrast test,proper substitution of carbamate was identified for phosphate-carbamate amylose. Gelatiniiation temperature, viscosity and viscosity thermal stability were tested and contrasted for pho9phate-carbamate amylose sizing,phosphate amylose and PVA blending sizing,phosphate amylose sizing ,phosphate starch sizing,amylose sizing.com starch sizing. The above sizings were used to size C 19.5 tex yam and T/C 13 tat yam,strength and elongation of the sized yam were tested and contrasted. The result shows that sizing properties of phosphate-carbamate amylose and phosphate amylase & PVA are basically same and better than that of the other sizing obviously, sizing demands of pure cottan yarn and polyester cotton blended yarn can be reached. It is considered that phosphaie-carbamate amylose can be textile size mixture or replace PVA.%探讨磷酸-氨基甲酸酯直链淀粉的浆液性能.制备了磷酸-氨基甲酸酯直链淀粉、磷酸酯直链淀粉、磷酸酯淀粉,并采用对比试验确定了磷酸-氨基甲酸酯直链淀粉适宜于上浆的氨基甲酸酯取代度;测定并比较了磷酸-氨基甲酸酯直链淀粉浆液、磷酸酯直链淀粉和PVA混合浆液、磷酸酯直链淀粉浆液、磷酸酯淀粉浆液、直链淀粉浆液、玉米淀粉浆液的糊化温度、黏度和黏度热稳定性;用以上各种浆液在C 19.5 tex纱和T/C13 tex纱上进行了上浆试验,并进行了强伸性测定和比较.结果表明:磷酸-氧基甲酸酯直链淀粉浆液与磷酸酯直链淀粉和PVA混合浆液的性能基本相当,明显好于其他浆液,可满足纯棉纱和涤棉纱的上浆要求.认为磷酸-氧基甲酸酯直链淀粉浆液有可能成为取代PVA的纺织浆料.

  6. DNA Methylation in Thyroid Tumorigenesis

    Thyroid cancer is the most common endocrine cancer with 1,690 deaths each year. There are four main types of which the papillary and follicular types together account for >90% followed by medullary cancers with 3% to 5% and anaplastic carcinomas making up <3%. Epigenetic events of DNA hypermethylation are emerging as promising molecular targets for cancer detection. Our immediate and long term goal is to identify DNA methylation markers for early detection of thyroid cancer. This pilot study comprised of 21 patients to include 11 papillary thyroid cancers (PTC), 2 follicular thyroid cancers (FTC), 5 normal thyroid cases, and 3 hyperthyroid cases. Aberrant promoter methylation was examined in 24 tumor suppressor genes using the methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) assay and in the NIS gene using methylation-specific PCR (MSP). The frequently methylated genes were CASP8 (17/21), RASSF1 (16/21) and NIS (9/21). In the normal samples, CASP8, RASSF1 and NIS were methylated in 5/5, 4/5 and 1/5 respectively. In the hyperthyroid samples, CASP8, RASSF1 and NIS were methylated in 3/3, 2/3 and 1/3 respectively. In the thyroid cancers, CASP8, RASSF1, and NIS were methylated in 9/13, 10/13, and 7/13 respectively. CASP8, RASSF1 and NIS were also methylated in concurrently present normal thyroid tissue in 3/11, 4/11 and 3/11 matched thyroid cancer cases (matched for presence of both normal thyroid tissue and thyroid cancer), respectively. Our data suggests that aberrant methylation of CASP8, RASSF1, and NIS maybe an early change in thyroid tumorigenesis regardless of cell type

  7. Adsorption of the enantiomers of 3-chloro-1-phenyl-propanol on silica-bonded chiral quinidine carbamate

    Asnin, Leonid [University of Tennessee, Knoxville (UTK); Kaczmarski, Krzysztof [University of Tennessee and Rzeszow University of Technology, Poland; Felinger, Attila [ORNL; Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

    2005-10-01

    The interactions of 3-chloro-1-phenyl-propanol with a quinidine carbamate-bonded chiral stationary phase under NPLC conditions were studied by measuring the adsorption isotherm data of its enantiomers by frontal analysis, modeling these data with a suitable isotherm model, and comparing the experimental overloaded elution band profiles with those calculated with this isotherm and the equilibrium dispersive model of liquid chromatography. The affinity energy distribution was calculated from the adsorption isotherm data. The results show that the surface of the adsorbent is heterogeneous and exhibits a bimodal adsorption energy distribution. This fact is interpreted in terms of the presence of two different types of adsorption sites on the stationary phase, nonselective and enantioselective sites. Albeit the bi-Langmuir isotherm model successfully accounts for the single-component data corresponding to both enantiomers, the competitive bi-Langmuir isotherm model does not allow an accurate prediction of the overloaded band profiles of the racemic mixture. Thermodynamic data are drawn for explanation. Some aspects of the retention mechanism are discussed in the light of the data obtained.

  8. Changes of ethyl carbamate and its precursors in maesil (Prunus mume) extract during one-year fermentation.

    Choi, Bogyoung; Koh, Eunmi

    2016-10-15

    The contents of ethyl carbamate (EC), cyanide, and ethanol were determined in maesil extracts that are liquids generated from fermentation of maesil fruit and brown sugar at 25°C or 15°C for one year. EC was detected from day 150 with a maximum value of 9.7μg/kg. The cyanide levels increased with prolonged soaking time of maesil and decreased at day 150 where EC was firstly detected, indicating that cyanide is a precursor of EC. Ethanol slowly increased at 25°C, while it fluctuated at 15°C. The contents of EC, cyanide, and ethanol were higher in the extracts fermented at 25°C compared with those at 15°C. EC contents had a higher positive correlation with cyanide contents (R=0.658) than ethanol contents (R=0.351). These results indicate that fermenting temperature gave a rise of EC precursors and consequently led to the increase of EC in the maesil extract. PMID:27173569

  9. The Stepwise Behavioral Responses: Behavioral Adjustment of the Chinese Rare Minnow (Gobiocypris rarus in the Exposure of Carbamate Pesticides

    Zongming Ren

    2013-01-01

    Full Text Available In order to illustrate the behavioral regulation in environmental stress, the behavioral responses of the Chinese rare minnow (Gobiocypris rarus to arprocarb, carbofuran, and oxamyl were analyzed with an online monitoring system. The Self-Organizing Map (SOM was used to define the patterns of the behavioral data obtained from treatments at concentrations of 0.1 toxic unit (TU, 1 TU, 2 TU, 5 TU, 10 TU, and 20 TU and a control. In certain cases, differences among the carbamate pesticides (CPs tested were observed. The profiles of behavioral strength (BS in SOM varied according to the concentration used. The time of the first significant decrease of the BS varied inversely with the CP concentrations. The results suggested that the behavioral regulation in the stepwise behavioral responses (SBR was evident. The primary movement behaviors shown by the SBR model included no effect, stimulation, acclimation, adjustment (readjustment, and toxic effect, especially at the lower concentrations. However, higher stress (10 TU and 20 TU might limit the function of the behavioral adjustment produced by the intrinsic response mechanisms. It was concluded that SBR, which were affected by both the concentration and the exposure time, could be used as a suitable indicator in the ecotoxicological risk assessment of CPs.

  10. Studies on the Purification and Characterization of Soybean Esterase,and Its Sensitivity to Organophosphate and Carbamate Pesticides

    LI Jian-ke; ZHOU Yan-li; WEN Yan-xia; WANG Jian-hua; HU Qiu-hui

    2009-01-01

    Soybean esterase,a cholinesterase-like enzyme,was purified by differential centrifugation firstly,then,ammonium sulfate precipitation,dialysis,and finally,DEAE-cellulose-32 ion-exchange chromatography after extracting it from soybean seeds with phosphate buffer(0.3 mol L-1,pH 7.0).The extract recovery rate of the purified enzyme was 8.18% and purification fold was 91.58.The soybean esterase appeared as two bands on the denaturing SDS-PAGE with molecular weights of 24 and 37.2 kDa,respectively,which proved that it is a dimer protein consisting of two subunits.The result of nondenaturing PAGE revealed that the soybean esterase is a single band with cholinesterase-like activity using α-naphthyl acetate as the substrate and fast blue B salt as coloring agent.The esterase showed very high sensitivity to 18 kinds of organophosphate pesticides and 6 kinds of carbamate pesticides with the lowest detective limits of 0.03125-0.0625 and 0.03 125-0.25 mg kg-1,respectively,and can meet the demands of MRL specified by the most countries.

  11. Mechanism and kinetic study on the gas-phase reactions of OH radical with carbamate insecticide isoprocarb

    Zhang, Chenxi; Yang, Wenbo; Bai, Jing; Zhao, Yuyang; Gong, Chen; Sun, Xiaomin; Zhang, Qingzhu; Wang, Wenxing

    2012-12-01

    As one of the most important carbamate insecticides, isoprocarb [2-(1-methylethyl) phenyl methylcarbamate, MIPC] is widely used in agricultural and cotton spraying. The atmospheric chemical reaction mechanism and kinetics of MIPC with OH radical have been researched using the density functional theory in this paper. The study shows that OH radical is more easily added to the C atoms of aromatic ring than to carbon-oxygen double bond, while the H atom is abstracted more difficulty from -CONH- group and aromatic ring than from the -CH3- group and the -CH- group. At room temperature, the total rate constant of MIPC with OH radical is about 5.1 × 10-12 cm3 molecule-l s-l. OH radical addition reaction and H atom abstraction reaction are both important for the OH-initiated reaction of MIPC. The energy-rich adducts (MIPC-OH) and the MIPC's radical isomers are open-shell activated radicals and can be further oxidized in the atmosphere.

  12. Electrochemical synthesis of niobium methylate

    The formation of niobium(V) methylate in methanol against the background of lithium chloride is studied. It is found that, in the anodic dissolution of niobium in the diaphragm-free electrolytic tank, formed niobium(V) methylate is partially reduced to the four-valent state at the cathode. In order to suppress the reduction of Nb(V), an electrolytic tank was designed, which enabled one to separate the anolyte from the catholyte using the difference between their densities. Niobium methylate was not found in the anolyte; however, it formed as a result of mixing the anolyte with the catholyte after completion of electrolysis. The current efficiency of niobium methylate of 96-97% was achieved. Possible mechanism of the process is discussed

  13. Research advances in formation mechanism and controlling approach of the ethyl carbamate in rice wine%黄酒中氨基甲酸乙酯形成机理及控制方法研究进展

    白卫东; 沈棚; 钱敏

    2012-01-01

    Ethyl carbamate is one of a carcinogenic substance in rice wine. The review introduced the formation mechanism of ethyl carbamate, the influence of the process of making wine on its formation and its methods of monitoring. In addition, the research progress was introduced. It can provide some reference in controlling the content of ethyl carbamate in rice wine for enterprises.%氨基甲酸乙酯是一种存在于黄酒中的致癌物质.该文主要从氨基甲酸乙酯的形成机理,酿造工艺对其形成影响和控制方法等方面进行综述,同时对未来研究方向进行了展望.旨在为企业更好地控制黄酒中的氨基甲酸乙酯含量提供参考.

  14. A Booster Pump Added on the High-Pressure Ammonium Carbamate Pump Inlet%高压甲铵泵入口增加甲铵升压泵简介

    张青林

    2014-01-01

    During the 30・52 CO2 stripping urea plant operation ,the outlet pressure of the high‐pressure ammonium carbamate pump is low due to the low concentration of ammonium carbamate , and the whole unit is in disorder to be shut down . After adding the booster pump on the high‐pressure ammonium carbamate pump inlet ,the normal operation is ensured ,but some new problems are not yet solved .%30・52 CO2汽提法尿素装置开车过程中,因甲铵液浓度低,高压甲铵泵出口压力低,导致合成系统紊乱而被迫停车;在高压甲铵泵入口增设一台升压泵后,确保了系统的正常运行,但也带来新问题尚待解决。

  15. HISTONE METHYLATION REGULATES MEMORY FORMATION

    Gupta, Swati; Kim, Se Y.; Artis, Sonja; Molfese, David L.; Schumacher, Armin; Sweatt, J. David; Paylor, Richard E.; Lubin, Farah D.

    2010-01-01

    It has been established that regulation of chromatin structure through post-translational modification of histone proteins, primarily histone H3 phosphorylation and acetylation, is an important early step in the induction of synaptic plasticity and formation of long-term memory. In this study, we investigated the contribution of another histone modification, histone methylation, to memory formation in the adult hippocampus. We found that tri-methylation of histone H3 at lysine 4 (H3K4), an ac...

  16. Methylation: a regulator of HIV-1 replication?

    Jeang Kuan-Teh; Yedavalli Venkat RK

    2007-01-01

    Abstract Recent characterizations of methyl transferases as regulators of cellular processes have spurred investigations into how methylation events might influence the HIV-1 life cycle. Emerging evidence suggests that protein-methylation can positively and negatively regulate HIV-1 replication. How DNA- and RNA- methylation might impact HIV-1 is also discussed.

  17. Penetration of methyl isocyanate through organic vapor and acid gas respirator cartridges.

    Moyer, E S; Berardinelli, S P

    1987-04-01

    Methyl isocyanate (MIC) is a volatile, toxic chemical [Threshold Limit Value (TLV) = 0.02 ppm] used to manufacture carbamate pesticides. The principal manufacturer of MIC is Union Carbide, and the site of production is Institute, West Virginia. In light of the December 1984 Bhopal, India disaster and possible safety problems at the Institute facility, NIOSH conducted this research as a basis upon which to recommend protective equipment that might be used in an emergency situation where extremely high MIC concentrations might be encountered. Both protective clothing and respirators were evaluated. In particular, NIOSH studied air-purifying respirators in order to assess their effectiveness against MIC vapor penetration. NIOSH does not recommend any air purifying respirator for MIC because of its high toxicity and lack of warning properties and because no effective end of service life indicator currently is available for MIC. This report addresses only MIC penetration through air-purifying cartridges at challenge concentrations designed to simulate emergency escape conditions. Another report addresses the protective clothing issue. The results presented are for two different manufacturers' organic vapor (OV) and acid gas cartridges. Penetration tests were conducted at three or four MIC challenge concentrations and at three different humidity conditions. In general, breakthrough times (1% of challenge concentration) were very short (less than 20 min). Also, high relative humidity was found to decrease the breakthrough time of MIC. PMID:3591646

  18. [Determination of 51 carbamate pesticide residues in vegetables by liquid chromatography-tandem mass spectrometry based on optimization of QuEChERS sample preparation method].

    Wang, Lianzhu; Zhou, Yu; Huang, Xiaoyan; Wang, Ruilong; Lin, Zixu; Chen, Yong; Wang, Dengfei; Lin, Dejuan; Xu, Dunming

    2013-12-01

    The raw extracts of six vegetables (tomato, green bean, shallot, broccoli, ginger and carrot) were analyzed using gas chromatography-mass spectrometry (GC-MS) in full scan mode combined with NIST library search to confirm main matrix compounds. The effects of cleanup and adsorption mechanisms of primary secondary amine (PSA) , octadecylsilane (C18) and PSA + C18 on co-extractives were studied by the weight of evaporation residue for extracts before and after cleanup. The suitability of the two versions of QuEChERS method for sample preparation was evaluated for the extraction of 51 carbamate pesticides in the six vegetables. One of the QuEChERS methods was the original un-buffered method published in 2003, and the other was AOAC Official Method 2007.01 using acetate buffer. As a result, the best effects were obtained from using the combination of C18 and PSA for extract cleanup in vegetables. The acetate-buffered version was suitable for the determination of all pesticides except dioxacarb. Un-buffered QuEChERS method gave satisfactory results for determining dioxacarb. Based on these results, the suitable QuEChERS sample preparation method and liquid chromatography-positive electrospray ionization-tandem mass spectrometry under the optimized conditions were applied to determine the 51 carbamate pesticide residues in six vegetables. The analytes were quantified by matrix-matched standard solution. The recoveries at three levels of 10, 20 and 100 microg/kg spiked in six vegetables ranged from 58.4% to 126% with the relative standard deviations of 3.3%-26%. The limits of quantification (LOQ, S/N > or = 10) were 0.2-10 microg/kg except that the LOQs of cartap and thiofanox were 50 microg/kg. The method is highly efficient, sensitive and suitable for monitoring the 51 carbamate pesticide residues in vegetables. PMID:24669707

  19. [Xenopsylla cheopis (Siphonaptera: Xenopsyllinae), fleas in rural plague areas of high altitude Madagascar: level of sensitivity to DDT, pyrethroids and carbamates after 50 years of chemical vector control].

    Ratovonjato, J; Duchemin, J B; Duplantier, J M; Chanteau, S

    2000-01-01

    The resistance of Xenopsylla cheopis from urban area to pyrethroids, to DDT, and their susceptibility to carbamate are known. We have evaluated the susceptibility of X. cheopis collected from three rural localities: Ambodisiarivo (district of Antananarivo Avaradrano), Mandoto (district of Betafo), Analaroa (district of Anjozorobe) in the province of Antananarivo and in Besoa (district of Ambalavao) in the province of Fianarantsoa. The standard WHO protocol was used and four insecticides were tested: deltamethrin 0.025%, cyfluthrin 0.15% (pyrethroids), DDT 4% (organochlorine), propoxur 1% and bendiocarb 0.1% (carbamate). X. cheopis has been shown resistance to DDT 4%, to deltamethrin 0.025% but was susceptible in the rural area around Antananarivo City. They were tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1% in the districts of Betafo and Anjozorobe. In Besoa, X. cheopis was resistant to DDT 4%, tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1%. These results indicate that DDT and pyrethroids can not be recommended any more for the vector control in the rural area around the capital. The use of pyrethroids in the other districts of the central highland must be joined with a X. cheopis susceptibility control. In case of resistance to pyrethroids, carbamates would be proposed to control plague vector in the rural area. The high level of resistance to DDT and pyrethroid in the rural area around the capital confirms the importance of studying the flea population in different area of Madagascar and the possibility of the gene resistance propagation. PMID:12463026

  20. Teores de carbamato de etila em aguardentes de cana e mandioca: parte II Contents of ethyl carbamate in sugar cane and manioc spirits: part II

    Luiz Gualberto de Andrade Sobrinho

    2009-01-01

    Full Text Available Herein, we report the concentration of ethyl carbamate (EC and copper in 380 samples of sugar-cane spirit and 45 samples of manioc spirit as determined by GC-MS and FAAS respectively. The cyanide content determined spectrophotometrically is reported for the manioc spirit. Sugar cane spirit produced by alembic distillation (70,0 µg L-1 shown a lower content of EC than samples produced by column distillation (270 µg L-1. No simple correlation between the content of EC and copper for sugar cane spirit as well among the concentration of EC, copper, and cyanide for manioc spirit could be observed.

  1. Teores de carbamato de etila em aguardentes de cana e mandioca: parte II Contents of ethyl carbamate in sugar cane and manioc spirits: part II

    Luiz Gualberto de Andrade Sobrinho; Luciana Tereza Dias Cappelini; Alexandre Ataíde da Silva; Carlos Alexandre Galinaro; Silmara França Buchviser; Daniel Rodrigues Cardoso; Douglas Wagner Franco

    2009-01-01

    Herein, we report the concentration of ethyl carbamate (EC) and copper in 380 samples of sugar-cane spirit and 45 samples of manioc spirit as determined by GC-MS and FAAS respectively. The cyanide content determined spectrophotometrically is reported for the manioc spirit. Sugar cane spirit produced by alembic distillation (70,0 µg L-1) shown a lower content of EC than samples produced by column distillation (270 µg L-1). No simple correlation between the content of EC and copper for sugar ca...

  2. Hypervalent iodine(iii)-promoted N-incorporation into N-aryl vinylogous carbamates to quinoxaline diesters: access to 1,4,5,8-tetraazaphenanthrene.

    Sagar, A; Vidaycharan, Shinde; Shinde, Anand H; Sharada, Duddu S

    2016-04-26

    A novel oxidative N-incorporation strategy for synthesis of quinoxaline diesters under metal-free conditions is described for the first time. The mild reaction conditions allow for this transformation via the formation of two C(sp(2))-N bonds utilizing cheaply available NaN3 as the N-atom source. N-Aryl vinylogous carbamates in this study undergo azidation at enamino C(sp(2))-H selectively. The robustness of this strategy is further demonstrated by the synthesis of a valuable 1,4,5,8-tetraazaphenanthrene derivative using a mild and convenient approach. PMID:27050385

  3. (1S,3S,4S)-tert-Butyl N-[1-benzyl-3-hydr­oxy-5-phenyl-4-(picolinamido)pent­yl]carbamate

    Jian-Feng Zheng; Su-Yu Huang; Jian-Nan Guo; Yu Zhang; Li-Ren Jin

    2008-01-01

    The title compound, C29H35N3O4, was obtained by the reaction of (2S,4S,5S)-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentyl)carbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1)° with the phenyl ring of the terminal benzyl group and 14.3 (1)...

  4. Allergic reaction induced by dermal and/or respiratory exposure to low-dose phenoxyacetic acid, organophosphorus, and carbamate pesticides

    Several types of pesticides, such as organophosphates, phenoxyacetic acid, and carbamate have a high risk of affecting human health, causing allergic rhinitis and bronchial asthma-like diseases. We used our long-term sensitization method and a local lymph node assay to examine the allergic reactions caused by several types of pesticides. BALB/c mice were topically sensitized (9 times in 3 weeks), then challenged dermally or intratracheally with 2,4-D, BRP, or furathiocarb. One day post-challenge, the mice were processed to obtain biologic materials for use in assays of total IgE levels in serum and bronchoalveolar lavage fluid (BALF); differential cell counts and chemokine levels in BALF; lymphocyte counts and surface antigen expression on B-cells within regional lymph nodes (LNs); and, ex situ cytokine production by cells from these LNs. 2,4-D-induced immune responses characteristic of immediate-type respiratory reactions, as evidenced by increased total IgE levels in both serum and BALF; an influx of eosinophils, neutrophils, and chemokines (MCP-1, eotaxin, and MIP-1β) in BALF; increased surface antigen expression on B-cells IgE and MHC class II production) in both auricular and the lung-associated LNs; and increased Th2 cytokine production (IL-4, IL-5, IL-10, and IL-13) in both auricular and the lung-associated LN cells. In contrast, BRP and furathiocarb treatment yielded, at most, non-significant increases in all respiratory allergic parameters. BRP and furathiocarb induced marked proliferation of MHC Class II-positive B-cells and Th1 cytokines (IL-2, TNF-α, and IFN-γ) in only auricular LN cells. These results suggest that 2,4-D is a respiratory allergen and BRP and furathiocarb are contact allergens. As our protocol detected classified allergic responses to low-molecular-weight chemicals, it thus may be useful for detecting environmental chemical-related allergy.

  5. Chromogenic platform based on recombinant Drosophila melanogaster acetylcholinesterase for visible unidirectional assay of organophosphate and carbamate insecticide residues

    Highlight: ► A visible chromogenic platform for rapid analysis of OP and CM insecticide residues was developed. ► The assay has the capabilities of both qualitative measurement and quantitative analysis. ► The sensitivity, capabilities of resisting interferences and storage stability were desirable. ► Matrix effects were acceptable and detection performance was satisfactory in real application. - Abstract: In this study we propose a chromogenic platform for rapid analysis of organophosphate (OP) and carbamate (CM) insecticide residues, based on recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) as enzyme and indoxyl acetate as substrate. The visible chromogenic strip had the advantages identical to those of commonly used lateral flow assays (LFAs) with utmost simplicity in sample loading and result observation. After optimization, depending on the color intensity (CI) values, the well-established assay has the capabilities of both qualitative measurement via naked eyes and quantitative analysis by colorimetric reader with the desirable IC50 values against the tested six insecticides (0.06 μg mL−1 of carbofuran, 0.28 μg mL−1 of methomyl, 0.03 μg mL−1 of dichlorvos, 31.6 μg mL−1 of methamidophos, 2.0 μg mL−1 of monocrotophos, 6.3 μg mL−1 of omethoate). Acceptable matrix effects and satisfactory detection performance were confirmed by in-parallel LC–MS/MS analysis in different vegetable varieties at various spiked levels of 10−3 to 101 μg g−1. Overall, the testified suitability and applicability of this novel platform meet the requirements for practical use in food safety management and environmental monitoring, especially in the developing world.

  6. Chromogenic platform based on recombinant Drosophila melanogaster acetylcholinesterase for visible unidirectional assay of organophosphate and carbamate insecticide residues

    Han Zheng [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Chi Chensen [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Bai Bing; Liu Gang; Rao Qinxiong [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Peng Shaojie [Institute of Shanghai Food and Drug Supervision, 615 Liuzhou Road, Shanghai 200233 (China); Liu Hong [Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhongshan West Road, Shanghai 200336 (China); Zhao Zhihui [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Zhang Dabing [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Wu Aibo, E-mail: wuaibo@saas.sh.cn [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China)

    2012-03-30

    Highlight: Black-Right-Pointing-Pointer A visible chromogenic platform for rapid analysis of OP and CM insecticide residues was developed. Black-Right-Pointing-Pointer The assay has the capabilities of both qualitative measurement and quantitative analysis. Black-Right-Pointing-Pointer The sensitivity, capabilities of resisting interferences and storage stability were desirable. Black-Right-Pointing-Pointer Matrix effects were acceptable and detection performance was satisfactory in real application. - Abstract: In this study we propose a chromogenic platform for rapid analysis of organophosphate (OP) and carbamate (CM) insecticide residues, based on recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) as enzyme and indoxyl acetate as substrate. The visible chromogenic strip had the advantages identical to those of commonly used lateral flow assays (LFAs) with utmost simplicity in sample loading and result observation. After optimization, depending on the color intensity (CI) values, the well-established assay has the capabilities of both qualitative measurement via naked eyes and quantitative analysis by colorimetric reader with the desirable IC{sub 50} values against the tested six insecticides (0.06 {mu}g mL{sup -1} of carbofuran, 0.28 {mu}g mL{sup -1} of methomyl, 0.03 {mu}g mL{sup -1} of dichlorvos, 31.6 {mu}g mL{sup -1} of methamidophos, 2.0 {mu}g mL{sup -1} of monocrotophos, 6.3 {mu}g mL{sup -1} of omethoate). Acceptable matrix effects and satisfactory detection performance were confirmed by in-parallel LC-MS/MS analysis in different vegetable varieties at various spiked levels of 10{sup -3} to 10{sup 1} {mu}g g{sup -1}. Overall, the testified suitability and applicability of this novel platform meet the requirements for practical use in food safety management and environmental monitoring, especially in the developing world.

  7. Radiosynthesis and ex vivo evaluation of [11C-carbonyl]carbamate- and urea-based monoacylglycerol lipase inhibitors

    Introduction: Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) are the two primary enzymes that regulate the tone of endocannabinoid signaling. Although new PET radiotracers have been discovered for imaging FAAH in vivo, no such radiotracer exists for imaging MAGL. Here we report the radiosynthesis of five candidate MAGL radiotracers and their ex vivo evaluations in mice and rats. Methods: Candidate carbamate and urea MAGL inhibitors were radiolabeled at the carbonyl position by [11C]CO2 fixation. Radiotracers were administered (tail-vein injection) to rodents and brain uptake of radioactivity measured at early and late time points ex vivo. Specificity of uptake was explored by pretreatment with unlabeled inhibitors (2 mg/kg, ip) 30 min prior to radiotracer administration. Results: All five candidate MAGL radiotracers were prepared in high specific activity (> 65 GBq/μmol) and radiochemical purity (> 98%). Moderate brain uptake (0.2–0.8 SUV) was observed for each candidate while pretreatment did not reduce uptake for four of the five tested. For two candidates ([11C]12 and [11C]14), high retention of radioactivity was observed in the blood (ca. 10 and 4 SUV at 40 min) which was blocked by pretreatment with unlabeled inhibitors. The most promising candidate, [11C]18, demonstrated moderate brain uptake (ca. 0.8 SUV) which showed circa 50% blockade by pretreatment with unlabeled 18. Conclusion: One putative and four reported potent and selective MAGL inhibitors have been radiolabeled via [11C]CO2 fixation as radiotracers for this enzyme. Despite the promising in vitro pharmacological profile, none of the five candidate radiotracers exhibited in vivo behavior suitable for PET neuroimaging

  8. Influence of a carbamate pesticide on growth, respiration (14C)-carbon metabolism and symbiosis of a Rhizobium sp

    Addition of aldicarb (2 methyl-2(methyl thio) propionaldehyde-O-methyl carbamoyl oxime) in the growth medium enhanced the growth of Rhizobium sp. (cowpea group) at 2ppm level while an inhibition was observed at the normal (5 ppm) and higher (10 ppm) concentrations. Respiration of the cells was also inhibited by 5 and 10 ppm levels of the chemical eventhough a stimulation was observed at 2 ppm (lower) concentration. The insecticide, when incorporated at 5 and 10 ppm levels in the medium increased the 14C-glucose incorporation and considerably altered the assimilation of the radioactive carbon in different fractions of rhizobium cells. Soil application of this insecticide (Temik 10 G) reduced the number of nodules formed and the total nitrogen content in cowpea plants inoculated with the Rhizobium sp. but enhanced the dry matter production of cowpea plants. (Auth.)

  9. PCMdb: Pancreatic Cancer Methylation Database

    Nagpal, Gandharva; Sharma, Minakshi; Kumar, Shailesh; Chaudhary, Kumardeep; Gupta, Sudheer; Gautam, Ankur; Raghava, Gajendra P. S.

    2014-02-01

    Pancreatic cancer is the fifth most aggressive malignancy and urgently requires new biomarkers to facilitate early detection. For providing impetus to the biomarker discovery, we have developed Pancreatic Cancer Methylation Database (PCMDB, http://crdd.osdd.net/raghava/pcmdb/), a comprehensive resource dedicated to methylation of genes in pancreatic cancer. Data was collected and compiled manually from published literature. PCMdb has 65907 entries for methylation status of 4342 unique genes. In PCMdb, data was compiled for both cancer cell lines (53565 entries for 88 cell lines) and cancer tissues (12342 entries for 3078 tissue samples). Among these entries, 47.22% entries reported a high level of methylation for the corresponding genes while 10.87% entries reported low level of methylation. PCMdb covers five major subtypes of pancreatic cancer; however, most of the entries were compiled for adenocarcinomas (88.38%) and mucinous neoplasms (5.76%). A user-friendly interface has been developed for data browsing, searching and analysis. We anticipate that PCMdb will be helpful for pancreatic cancer biomarker discovery.

  10. Characterization of acetylcholinesterase from the brain of the Amazonian tambaqui (Colossoma macropomum) and in vitro effect of organophosphorus and carbamate pesticides.

    Assis, Caio Rodrigo Dias; Castro, Patrícia Fernandes; Amaral, Ian Porto Gurgel; Carvalho, Elba Verônica Matoso Maciel; Carvalho, Luiz Bezerra; Bezerra, Ranilson Souza

    2010-10-01

    In the present study, acetylcholinesterase (AChE) from the brain of the Amazonian fish tambaqui (Colossoma macropomum) was partially characterized and its activity was assayed in the presence of five organophosphates (dichlorvos, diazinon, chlorpyrifos, and tetraethyl pyrophosphate [TEPP]) and two carbamates (carbaryl and carbofuran) insecticides. Optimal pH and temperature were 7.0 to 8.0 and 45°C, respectively. The enzyme retained approximately 70% of activity after incubation at 50°C for 30 min. The insecticide concentration capable of inhibiting half of the enzyme activity (IC50) for dichlorvos, chlorpyrifos, and TEPP were calculated as 0.04 µmol/L, 7.6 µmol/L, and 3.7 µmol/L, respectively. Diazinon and temephos did not inhibit the enzyme. The IC50 values for carbaryl and carbofuran were estimated as 33.8 µmol/L and 0.92 µmol/L, respectively. These results suggest that AChE from the juvenile C. macropomum brain could be used as an alternative biocomponent of organophosphorus and carbamate biosensors in routine pesticide screening in the environment. PMID:20872688

  11. Vortex-Assisted Dispersive Micro-Solid Phase Extraction Using CTAB-Modified Zeolite NaY Sorbent Coupled with HPLC for the Determination of Carbamate Insecticides.

    Salisaeng, Pawina; Arnnok, Prapha; Patdhanagul, Nopbhasinthu; Burakham, Rodjana

    2016-03-16

    A vortex-assisted dispersive micro-solid phase extraction (VA-D-μ-SPE) based on cetyltrimethylammonium bromide (CTAB)-modified zeolite NaY was developed for preconcentration of carbamate pesticides in fruits, vegetables, and natural surface water prior to analysis by high performance liquid chromatography with photodiode array detection. The small amounts of solid sorbent were dispersed in a sample solution, and extraction occurred by adsorption in a short time, which was accelerated by vortex agitation. Finally, the sorbents were filtered from the solution, and the analytes were subsequently desorbed using an appropriate solvent. Parameters affecting the VA-D-μ-SPE performance including sorbent amount, sample volume, desorption solvent ,and vortex time were optimized. Under the optimum condition, linear dynamic ranges were achieved between 0.004-24.000 mg kg(-1) (R(2) > 0.9946). The limits of detection (LODs) ranged from 0.004-4.000 mg kg(-1). The applicability of the developed procedure was successfully evaluated by the determination of the carbamate residues in fruits (dragon fruit, rambutan, and watermelon), vegetables (cabbage, cauliflower, and cucumber), and natural surface water. PMID:26915268

  12. Synthesis of novel C17 steroidal carbamates. Studies on CYP17 action, androgen receptor binding and function, and prostate cancer cell growth.

    Moreira, Vânia M A; Vasaitis, Tadas S; Guo, Zhiyong; Njar, Vincent C O; Salvador, Jorge A R

    2008-11-01

    We have exploited the reaction of 1,1'-carbonylbis(2-methylimidazole) (CBMI) with several 17beta-hydroxy androstanes to synthesize a series of novel C17 steroidal carbamates. Structural elucidation features have been provided for the final compounds based on 1D and 2D NMR techniques, IR spectroscopy, and related literature. The new compounds were tested for inhibition of human cytochrome 17alpha-hydroxylase-C17,20-lyase (CYP17) and androgen receptor (AR) binding and function effects. Their inhibitory potential against PC-3 cell proliferation was also evaluated. Compounds 11 and 23 were found to inhibit CYP17 with IC50 values of 17.1 and 11.5 microM, respectively. The carbamate moiety at C17 allowed tight binding of the synthesized compounds to both wild-type (wt-) and mutated AR. When bound to the mutated AR, the compounds were found to have a dual effect, stimulating transcription at low concentrations while almost fully blocking it at the higher concentrations tested, in the presence of the natural androgen dihydrotestosterone (DHT). Compounds 8 and 12 were the most active against PC-3 cell proliferation with EC50 values of 2.2 and 0.2 microM, respectively. PMID:18582482

  13. Quantum chemical studies on solvents for post-combustion carbon dioxide capture: calculation of pKa and carbamate stability of disubstituted piperazines.

    Gangarapu, Satesh; Wierda, Gerben J; Marcelis, Antonius T M; Zuilhof, Han

    2014-06-23

    Piperazine is a widely studied solvent for post-combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of -CH(3), -CH(2)F, -CH(2)OH, -CH(2)NH(2), -COCH3 , and -CN groups of 2,5-disubstituted piperazines on the pKa and carbamate stability towards hydrolysis are investigated by quantum chemical methods. For the calculations, B3LYP, M11L, and spin-component-scaled MP2 (SCS-MP2) methods are used and coupled with the SMD solvation model. The experimental pK(a) values of piperazine, 2-methylpiperazine, and 2,5-dimethylpiperazine agree well with the calculated values. The present study indicates that substitution of -CH(3), -CH(2) NH(2), and -CH(2) OH groups on the 2- and 5-positions of piperazine has a positive impact on the CO(2) absorption capacity by reducing the carbamate stability towards hydrolysis. Furthermore, their higher boiling points, relative to piperazine itself, will lead to a reduction of volatility-related losses. PMID:24782140

  14. Sequential injection kinetic spectrophotometric determination of quaternary mixtures of carbamate pesticides in water and fruit samples using artificial neural networks for multivariate calibration

    Chu, Ning; Fan, Shihua

    2009-12-01

    A new analytical method was developed for the simultaneous kinetic spectrophotometric determination of a quaternary carbamate pesticide mixture consisting of carbofuran, propoxur, metolcarb and fenobucarb using sequential injection analysis (SIA). The procedure was based upon the different kinetic properties between the analytes reacted with reagent in flow system in the non-stopped-flow mode, in which their hydrolysis products coupled with diazotized p-nitroaniline in an alkaline medium to form the corresponding colored complexes. The absorbance data from SIA peak time profile were recorded at 510 nm and resolved by the use of back-propagation-artificial neural network (BP-ANN) algorithms for multivariate quantitative analysis. The experimental variables and main network parameters were optimized and each of the pesticides could be determined in the concentration range of 0.5-10.0 μg mL -1, at a sampling frequency of 18 h -1. The proposed method was compared to other spectrophotometric methods for simultaneous determination of mixtures of carbamate pesticides, and it was proved to be adequately reliable and was successfully applied to the simultaneous determination of the four pesticide residues in water and fruit samples, obtaining the satisfactory results based on recovery studies (84.7-116.0%).

  15. Assessing the Potential Content of Ethyl Carbamate in White, Red, and Rosé Wines as a Key Factor for Pursuing Urea Degradation by Purified Acid Urease.

    Cerreti, Martina; Fidaleo, Marcello; Benucci, Ilaria; Liburdi, Katia; Tamborra, Pasquale; Moresi, Mauro

    2016-07-01

    The ethyl carbamate (EC) content of a wine after a given temperature-time storage was theoretically predicted from the potential concentration of ethyl carbamate (PEC), as determined via an accelerated EC formation test. Such information was used to decide whether an enzymatic treatment was needed to reduce the wine urea level before bottling/aging. To this end, 6 white, red, and rosé wines, manufactured in Italy as such or enriched with urea, were tested for their PEC content either before or after enzymatic treatment using a purified acid urease preparation derived from Lactobacillus fermentum. The treatment was severely affected by the total phenolic content (TP) of the wine, the estimated pseudo-first-order kinetic rate constant for NH3 formation reducing by a factor of approximately 2000 as the TP increased from 0 to 1.64 g L(-1) . Such a sensitivity to TP was by far greater than that pertaining to a killed cell-based enzyme preparation used previously. Urea hydrolysis was successful at reducing EC concentration in wines with low levels of TP and other EC precursors. PMID:27239804

  16. Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

    Zhi Mei Liu; Xiao Huan Zang; Wei Hua Liu; Chun Wang; Zhi Wang

    2009-01-01

    A novel method for the determination of five carbamate pesticides(metolcarb,carbofuran,carbaryl,isoprocard and diethofencard)in water samples was developed by dispersive liquid-liquid microextraction(DLLME)coupled with high performance liquid chromatography-diode array detector(HPLC-DAD).Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results.Under the optimum conditions for the method,the calibration curve was linear in the concentration range from 5 to I000 ng mL-1 for all the five carbamate pesticides,with the correlation coefficients(r2)varying from 0.9984 to 0.9994.Good enrichment factors were achieved ranging from 80 to 177-fold,depending on the compound.The limits of detection(LODs)(S/N = 3)were ranged from 0.1 to 0.5 ng mL-1.The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

  17. In silico docking of methyl isocyanate (MIC) and its hydrolytic product (1, 3-dimethylurea) shows significant interaction with DNA Methyltransferase 1 suggests cancer risk in Bhopal-Gas- Tragedy survivors.

    Khan, Inbesat; Senthilkumar, Chinnu Sugavanam; Upadhyay, Nisha; Singh, Hemant; Sachdeva, Meenu; Jatawa, Suresh Kumar; Tiwari, Archana

    2015-01-01

    DNA methyltransferase 1 (DNMT1) is a relatively large protein family responsible for maintenance of normal methylation, cell growth and survival in mammals. Toxic industrial chemical exposure associated methylation misregulation has been shown to have epigenetic influence. Such misregulation could effectively contribute to cancer development and progression. Methyl isocyanate (MIC) is a noxious industrial chemical used extensively in the production of carbamate pesticides. We here applied an in silico molecular docking approach to study the interaction of MIC with diverse domains of DNMT1, to predict cancer risk in the Bhopal population exposed to MIC during 1984. For the first time, we investigated the interaction of MIC and its hydrolytic product (1,3-dimethylurea) with DNMT1 interacting (such as DMAP1, RFTS, and CXXC) and catalytic (SAM, SAH, and Sinefungin) domains using computer simulations. The results of the present study showed a potential interaction of MIC and 1,3-dimethylurea with these domains. Obviously, strong binding of MIC with DNMT1 interrupting normal methylation will lead to epigenetic alterations in the exposed humans. We suggest therefore that the MIC- exposed individuals surviving after 1984 disaster have excess risk of cancer, which can be attributed to alterations in their epigenome. Our findings will help in better understanding the underlying epigenetic mechanisms in humans exposed to MIC. PMID:26625778

  18. Synthesis, structural characterization, docking, lipophilicity and cytotoxicity of 1-[(1R)-1-(6-fluoro-1,3-benzothiazol-2-yl)ethyl]-3-alkyl carbamates, novel acetylcholinesterase and butyrylcholinesterase pseudo-irreversible inhibitors

    Pejchal, V.; Štěpánková, Š.; Pejchalová, M.; Královec, K.; Havelek, R.; Růžičková, Z.; Ajani, Haresh; Lo, Rabindranath; Lepšík, Martin

    Roč. 24, č. 7 ( 2016 ), s. 1560-1572. ISSN 0968-0896 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : halogenated benzothiazole * carbamates * acetylcholinesterase * butyrylcholinesterase inhibition * pseudo-irreversible mechanism * covalent docking Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.793, year: 2014

  19. Examining pyrethroids, carbamates and neonicotenoids in fish, water and sediments from the Indus River for potential health risks.

    Jabeen, Farhat; Chaudhry, Abdul Shakoor; Manzoor, Sadia; Shaheen, Tayybah

    2015-02-01

    This 3 × 3 factorial study assessed pyrethroids, carbamates and neonicotenoids groups of pesticides in replicated samples of three fish species from low (S1, reference), medium (S2) and heavy (S3) polluted sites receiving agricultural run-offs around the Indus River. Water and sediment samples from the same sites were also analysed for these pesticides by using high-performance liquid chromatography. Out of nine investigated pesticides, only three pesticides (deltamethrin, carbofuran and cypermethrin) were detected in fish and sediment samples. Deltamethrin in Cyprinus carpio ranged from 0.490 to 0.839 μg/g, mostly exceeding 0.5 μg/g as the maximum residual limit suggested by FAO-WHO, whereas it ranged from 0.214 to 0.318 μg/g in the sampled sediments. The carbofuran concentrations were 0.0425-0.066 and 0.613-0.946 μg/g in Labeo rohita and Channa marulius muscles respectively and 0.069-0.081 μg/g in the corresponding sediment samples. These values were either higher or lower than the maximum limit (0.1 μg/g) as suggested by FAO-WHO. Conversely, the cypermethrin concentration ranged from 0.141 to 0.174 in Ch. marulius and 0.183-0.197 μg/g in sediments which were both below the FAO-WHO maximum limit of 2 μg/g. No pesticide residues were detected in water from these sampling sites. Most selected physicochemical variables were within the acceptable range of World Health Organization for the water quality for aquatic life. The detected pesticide contents were mostly higher in fish muscles from heavily polluted sites. This is worrying because these pesticides may pose health risks for the fish and people of the study area. However, a preliminary risk assessment indicated that the calculated daily intake of detected pesticides by people consuming fish from the Indus River was low and did not present an immediate risk to the fish-consuming people. This study may be used as a benchmark to determine the safety of fish meat in order to develop intervention

  20. Poisoning of raptors with organophosphorus and carbamate pesticides with emphasis on Canada, U.S. and U.K.

    Mineau, P.; Fletcher, M.R.; Glaser, L.C.; Thomas, N.J.; Brassard, C.; Wilson, L.K.; Elliott, J.E.; Lyon, L.A.; Henny, C.J.; Bollinger, T.; Porter, S.L.

    1999-01-01

    We reviewed cases of raptor mortality resulting from cholinesterase-inhibiting pesticides. We compiled records from the U.S., U.K. and Canada for the period 1985-95 (520 incidents) and surveyed the relevant literature to identify the main routes of exposure and those products that led to the greatest number of poisoning cases. A high proportion of cases in the U.K. resulted from abusive uses of pesticides (willful poisoning). The proportion was smaller in North America where problems with labeled uses of pesticides were as frequent as abuse cases. Poisoning resulting from labeled use was possible with a large number of granular pesticides and some seed treatments through secondary poisoning or through the ingestion of contaminated invertebrates, notably earthworms. With the more toxic products, residue levels in freshly-sprayed insects were high enough to cause mortality. The use of organophosphorus products as avicides and for the topical treatment of livestock appeared to be common routes of intoxication. The use of insecticides in dormant oils also gave rise to exposure that can be lethal or which can debilitate birds and increase their vulnerability. A few pesticides of high toxicity were responsible for the bulk of poisoning cases. Based on limited information, raptors appeared to be more sensitive than other bird species to organophosphorus and carbamate pesticides. Some of the more significant risk factors that resulted in raptor poisonings were: insectivory and vermivory; opportunistic taking of debilitated prey; scavenging, especially if the gastrointestinal tracts are consumed; presence in agricultural areas; perceived status as pest species; and flocking or other gregarious behavior at some part of their life cycle. Lethal or sublethal poisoning should always be considered in the diagnosis of dead or debilitated raptors even when another diagnosis (e.g., electrocution, car or building strike) is apparent. Many cases of poisoning are not currently

  1. (Benzoylamino)methyl 4-Hydroxybenzoate

    Kristina Mladenovska; Emil Popovski

    2010-01-01

    (Benzoylamino)methyl 4-hydroxybenzoate (“Benzamidomethylparaben”) (3) was obtained from a reaction of 4-hydroxybenzoic acid (2) with a dioxane suspension of (benzamidomethyl)triethylammonium chloride (1). The phenolic group in 2 cannot be benzamidomethylated with 1 in aqueous media.

  2. Electronic transport in methylated fragments of DNA

    de Almeida, M. L.; Oliveira, J. I. N.; Lima Neto, J. X.; Gomes, C. E. M.; Fulco, U. L.; Albuquerque, E. L.; Freire, V. N.; Caetano, E. W. S.; de Moura, F. A. B. F.; Lyra, M. L.

    2015-11-01

    We investigate the electronic transport properties of methylated deoxyribonucleic-acid (DNA) strands, a biological system in which methyl groups are added to DNA (a major epigenetic modification in gene expression), sandwiched between two metallic platinum electrodes. Our theoretical simulations apply an effective Hamiltonian based on a tight-binding model to obtain current-voltage curves related to the non-methylated/methylated DNA strands. The results suggest potential applications in the development of novel biosensors for molecular diagnostics.

  3. Electronic transport in methylated fragments of DNA

    Almeida, M. L. de; Oliveira, J. I. N.; Lima Neto, J. X.; Gomes, C. E. M.; Fulco, U. L., E-mail: umbertofulco@gmail.com; Albuquerque, E. L. [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Freire, V. N. [Departamento de Física, Universidade Federal do Ceará, 60455-760 Fortaleza, CE (Brazil); Caetano, E. W. S. [Instituto Federal de Educação, Ciência e Tecnologia do Ceará, 60040-531 Fortaleza, CE (Brazil); Moura, F. A. B. F. de; Lyra, M. L. [Instituto de Física, Universidade Federal de Alagoas, 57072-900 Maceió-AL (Brazil)

    2015-11-16

    We investigate the electronic transport properties of methylated deoxyribonucleic-acid (DNA) strands, a biological system in which methyl groups are added to DNA (a major epigenetic modification in gene expression), sandwiched between two metallic platinum electrodes. Our theoretical simulations apply an effective Hamiltonian based on a tight-binding model to obtain current-voltage curves related to the non-methylated/methylated DNA strands. The results suggest potential applications in the development of novel biosensors for molecular diagnostics.

  4. Applicability of a carbamate insecticide multiresidue method for determining additional types of pesticides in fruits and vegetables.

    Krause, R T; August, E M

    1983-03-01

    Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbofuran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered. PMID:6853408

  5. 氯苯甘油氨酯缓释片的稳定性考察%Stability study of chlorphenesin carbamate sustained-release tablets

    卢欣; 王晶晶; 杨金荣; 房志仲

    2011-01-01

    Objective: To build a method in vitro and analyze the stability of chlorphenesin carbamate sustained-release tablets. Methods: Ultraviolet spectrophotometry method was used to determine the drug release of chlorphenesin carbamate sustained-release tablets ire vitro. High performance liquid chromatography method was used to determine the content of chlorphenesin carbamate sustained-release tablets and its related compounds. Results: Under the conditions of stress testing, the appearance, weight, hardness, content, related substance and release rate were stable. Result of accelerated testing and long-term testing showed that tablets with aluminum plastics package bag as package material were stable. Conclusion: The tablets are stable to illumination and high temperature, unstable to humidity. The tablets with moisture resistant packages are stable in acceleration and long-term testing.%目的:建立氯苯甘油氨酯缓释片的体外考察方法,并对其稳定性进行初步考察.方法:采用紫外分光光度法测定氯苯甘油氨酯缓释片体外释放度;采用高效液相色谱法测定氯苯甘油氨酯缓释片的药物含量和有关物质.结果:该制剂在各影响因素的实验条件下,样品的外观、重量、硬度、含量、有关物质、释放度没有明显变化;以铝塑包装袋为包装材料,进行加速、长期实验,制剂的稳定性良好.结论:氯苯甘油氨酯缓释片耐光照、高温,但在高湿条件下不稳定,选用防潮铝塑包装袋包装后,在加速实验和长期实验条件下基本稳定.

  6. Methyl 5-bromo-2-[methyl(methylsulfonylamino]benzoate

    Muneeb Hayat Khan

    2009-05-01

    Full Text Available The title compound, C10H12BrNO4S, is an intermediate in the synthesis of benzothiazine. The planar methyl ester group (maximum deviation is 0.0065 Å is oriented at a dihedral angle of 39.09 (13° with respect to the aromatic ring. In the crystal structure, weak intermolecular C—H...O interactions link the molecules into centrosymmetric dimers, through R22(10 ring motifs.

  7. Analysis of Ethyl Carbamate in Chinese Wines and Effects of Different Vintage Technologies on the Formation of Ethyl Carbamate%葡萄酒中氨基甲酸乙酯的含量测定及酿造工艺对其含量的影响

    于英; 李记明; 沈志毅; 姜文广

    2012-01-01

    调查了我国干红葡萄酒(77款)和干白葡萄酒(17款)中氨基甲酸乙酯(EC)含量情况,并探讨了酿酒工艺(果胶酶、酵母、乳酸菌和发酵温度等)对葡萄酒中氨基甲酸乙酯(EC)含量的影响。研究结果显示:干红葡萄酒中EC含量范围在7.00~26.80μg/L,平均浓度为17.90μg/L;干白葡萄酒中EC含量范围在6.40~21.58μg/L,平均浓度为11.35μg/L。葡萄酒酿造过程中EC的生成主要受酵母菌和乳酸菌种类的影响,酒精发酵温度的降低和果胶酶的使用有助于减少葡萄酒中EC的含量。%We used solid phase extraction and gas chromatography-flame ionization detector(SPE-GC-FID).Effects of different vintage technologies(pectases,yeasts,malolactic bacterias and fermentation temperature) on the formation of ethyl carbamate in Cabernet Gernischt wines during vinification were studied.The results showed the concentration range of ethyl carbamate in dry red wines was 7.00~26.80 μg/L,and the average was 17.90 μg/L.In dry white wines,the concentration range was 6.40~21.58 μg/L and the average was 11.35 μg/L.The ethyl carbamate is formed mainly from yeasts and malolactic bacterias during winemaking.The lower temperatures of alcoholic fermentation and the supplements of pectases before alcoholic fermentation could contribute to minimize the production of ethyl carbamate in wine.

  8. Folate deficiency affects histone methylation.

    Garcia, Benjamin A; Luka, Zigmund; Loukachevitch, Lioudmila V; Bhanu, Natarajan V; Wagner, Conrad

    2016-03-01

    Formaldehyde is extremely toxic reacting with proteins to crosslinks peptide chains. Formaldehyde is a metabolic product in many enzymatic reactions and the question of how these enzymes are protected from the formaldehyde that is generated has largely remained unanswered. Early experiments from our laboratory showed that two liver mitochondrial enzymes, dimethylglycine dehydrogenase (DMGDH) and sarcosine dehydrogenase (SDH) catalyze oxidative demethylation reactions (sarcosine is a common name for monomethylglycine). The enzymatic products of these enzymes were the demethylated substrates and formaldehyde, produced from the removed methyl group. Both DMGDH and SDH contain FAD and both have tightly bound tetrahydrofolate (THF), a folate coenzyme. THF binds reversibly with formaldehyde to form 5,10-methylene-THF. At that time we showed that purified DMGDH, with tightly bound THF, reacted with formaldehyde generated during the reaction to form 5,10-methylene-THF. This effectively scavenged the formaldehyde to protect the enzyme. Recently, post-translational modifications on histone tails have been shown to be responsible for epigenetic regulation of gene expression. One of these modifications is methylation of lysine residues. The first enzyme discovered to accomplish demethylation of these modified histones was histone lysine demethylase (LSD1). LSD1 specifically removes methyl groups from di- and mono-methylated lysines at position 4 of histone 3. This enzyme contained tightly bound FAD and the products of the reaction were the demethylated lysine residue and formaldehyde. The mechanism of LSD1 demethylation is analogous to the mechanism previously postulated for DMGDH, i.e. oxidation of the N-methyl bond to the methylene imine followed by hydrolysis to generate formaldehyde. This suggested that THF might also be involved in the LSD1 reaction to scavenge the formaldehyde produced. Our hypotheses are that THF is bound to native LSD1 by analogy to DMGDH and SDH and

  9. Methylated genes as new cancer biomarkers

    Brunner, Nils; Duffy, M.J; Napieralski, R.;

    2009-01-01

    measurement of the methylation status of the promoter regions of specific genes can aid early detection of cancer, determine prognosis and predict therapy responses. Promising DNA methylation biomarkers include the use of methylated GSTP1 for aiding the early diagnosis of prostate cancer, methylated PITX2 for...... predicting outcome in lymph node-negative breast cancer patients and methylated MGMT in predicting benefit from alkylating agents in patients with glioblastomas. However, prior to clinical utilisation, these findings require validation in prospective clinical studies. Furthermore, assays for measuring gene...

  10. miRNAting control of DNA methylation

    Ashwani Jha; Ravi Shankar

    2014-06-01

    DNA methylation is a type of epigenetic modification where a methyl group is added to the cytosine or adenine residue of a given DNA sequence. It has been observed that DNA methylation is achieved by some collaborative agglomeration of certain proteins and non-coding RNAs. The assembly of IDN2 and its homologous proteins with siRNAs recruits the enzyme DRM2, which adds a methyl group at certain cytosine residues within the DNA sequence. In this study, it was found that de novo DNA methylation might be regulated by miRNAs through systematic targeting of the genes involved in DNA methylation. A comprehensive genome-wide and system-level study of miRNA targeting, transcription factors, DNA-methylation-causing genes and their target genes has provided a clear picture of an interconnected relationship of all these factors which regulate DNA methylation in Arabidopsis. The study has identified a DNA methylation system that is controlled by four different genes: IDN2, IDNl1, IDNl2 and DRM2. These four genes along with various critical transcription factors appear to be controlled by five different miRNAs. Altogether, DNA methylation appears to be a finely tuned process of opposite control systems of DNA-methylation-causing genes and certain miRNAs pitted against each other.

  11. Altered DNA methylation in PAH deficient phenylketonuria.

    Dobrowolski, Steven F; Lyons-Weiler, James; Spridik, Kayla; Biery, Amy; Breck, Jane; Vockley, Jerry; Yatsenko, Svetlana; Sultana, Tamanna

    2015-01-01

    While phenylalanine (PHE) is the toxic insult in phenylketonuria (PKU), mechanisms underlying PHE toxicity remain ill-defined. Altered DNA methylation in response to toxic exposures is well-recognized. DNA methylation patterns were assessed in blood and brain from PKU patients to determine if PHE toxicity impacts methylation. Methylome assessment, utilizing methylated DNA immunoprecipitation and paired-end sequencing, was performed in DNA obtained from brain tissue of classical PKU patients, leukocytes from poorly controlled PKU patients, leukocytes from well controlled PKU patients, and appropriate control tissues. In PKU brain tissue, expression analysis determined the impact of methylation on gene function. Differential methylation was observed in brain tissue of PKU patients and expression studies identified downstream impact on gene expression. Altered patterns of methylation were observed in leukocytes of well controlled and poorly controlled patients with more extensive methylation in patients with high PHE exposure. Differential methylation of noncoding RNA genes was extensive in patients with high PHE exposure but minimal in well controlled patients. Methylome repatterning leading to altered gene expression was present in brain tissue of PKU patients, suggesting a role in neuropathology. Aberrant methylation is observed in leukocytes of PKU patients and is influenced by PHE exposure. DNA methylation may provide a biomarker relating to historic PHE exposure. PMID:25990862

  12. Avocado and olive oil methyl esters

    Biodiesel, the mono-alkyl esters of vegetable oils, animal fats or other triacylglycerol-containing materials and an alternative to conventional petroleum-based diesel fuel, has been derived from a variety of feedstocks. Numerous feedstocks have been investigated as potential biodiesel sources, including commodity oils, however, the methyl esters of avocado and olive oil would likely be suitable as biodiesel fuel. In order to expand the database and comprehensive evaluation of the properties of vegetable oil esters, in this work the fuel-related properties of avocado and olive oil methyl esters, which exhibit similar fatty acid profiles including high oleic acid content, are determined. The cetane numbers of avocado oil methyl esters and olive oil methyl esters are relatively high, determined as 59.2 and 62.5, respectively, due to their elevated content of methyl oleate. Other properties are well within the ranges specified in biodiesel standards. The cloud points of both esters are slightly above 0 °C due to their content of saturated esters, especially methyl palmitate. Overall, avocado and olive oil yield methyl esters with fuel properties comparable to methyl esters from other commodity vegetable oils. The 1H and 13C NMR spectra of avocado and olive oil methyl esters are reported. -- Highlights: • Methyl esters of avocado and olive oil meet biodiesel fuel standards. • Provides comparison for methyl esters of other vegetable oils with high oleic content. • Discusses and compares present results with prior literature

  13. Methylated genes as new cancer biomarkers.

    Duffy, M J

    2012-02-01

    Aberrant hypermethylation of promoter regions in specific genes is a key event in the formation and progression of cancer. In at least some situations, these aberrant alterations occur early in the formation of malignancy and appear to be tumour specific. Multiple reports have suggested that measurement of the methylation status of the promoter regions of specific genes can aid early detection of cancer, determine prognosis and predict therapy responses. Promising DNA methylation biomarkers include the use of methylated GSTP1 for aiding the early diagnosis of prostate cancer, methylated PITX2 for predicting outcome in lymph node-negative breast cancer patients and methylated MGMT in predicting benefit from alkylating agents in patients with glioblastomas. However, prior to clinical utilisation, these findings require validation in prospective clinical studies. Furthermore, assays for measuring gene methylation need to be standardised, simplified and evaluated in external quality assurance programmes. It is concluded that methylated genes have the potential to provide a new generation of cancer biomarkers.

  14. DNA methylation in hepatocellular carcinoma

    Iris Tischoff; Andrea Tannapfel

    2008-01-01

    As for many other tumors, development of hepatocellular carcinoma (HCC) must be understood as a multistep process with accumulation of genetic and epigenetic alterations in regulatory genes, leading to activation of oncogenes and inactivation or loss of tumor suppressor genes (TSG). In the last decades, in addition to genetic alterations, epigenetic inactivation of (tumor suppressor) genes by promoter hypermethylation has been recognized as an important and alternative mechanism in tumorigenesis. In HCC, aberrant methylation of promoter sequences occurs not only in advanced tumors, it has been also observed in premalignant conditions just as chronic viral hepatitis B or C and cirrhotic liver. This review discusses the epigenetic alterations in hepatocellular carcinoma focusing DNA methylation.

  15. Liquid chromatography and mass spectrometry for the analysis of N-β-methylamino-L-alanine with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate.

    Glover, W Broc; Cohen, Steven A; Murch, Susan J

    2015-01-01

    Numerous studies in the past decade have identified N-β-methylamino-L-alanine (BMAA) as a putative environmental neurotoxin. Produced by cyanobacteria and accumulated at different levels of the trophic system, BMAA has been detected in the brain tissue of human patients that died from progressive neurodegenerative disease. Research into the mechanism of neurotoxicity has been hampered by conflicting results and disagreement in the literature over analytical methods used for quantification and detection. While several research approaches have been tested, the use of the derivatizing reagent 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate is presented here as an effective and selective means for the analysis of BMAA and two co-occurring biological isomers, DAB and AEG, by liquid chromatography and tandem mass spectrometry. PMID:25323521

  16. A review of ethyl carbamate and polycyclic aromatic hydrocarbon contamination risk in cachaça and other Brazilian sugarcane spirits.

    Riachi, L G; Santos, A; Moreira, R F A; De Maria, C A B

    2014-04-15

    Sixteen polycyclic aromatic hydrocarbons (PAHs) have been identified in Brazilian sugarcane spirits. Contamination sources are: sugarcane burn before harvest and petroleum derivatives. PAHs concentration in spirits produced from burned cane was about 2-3 times higher than those from unburned cane. Benzo(a)pyrene (BaP) is present at less than 1%, and therefore is not a representative marker of cachaça contamination by PAHs. Ethyl carbamate (EC) is produced during both fermentation and distillation. During distillation, cupric ions may catalyse the conversion of cyanide to EC. In discontinuous distillation, the use of the heart fraction for bottling cachaça considerably decreases its concentration. In the continuous process, in which there is no separation of distillate, it is highly recommended to couple cooling devices and reflux systems to the distillation column. Consumers are at a greater risk of EC exposure from cachaça than from any other spirit. PMID:24295690

  17. tert-Butyl N-[2-(N-isobutyl-4-meth­oxy­benzene­sulfonamido)­eth­yl]carbamate

    Xiao-Guang Bai; Ju-Xian Wang

    2014-01-01

    The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso­butyl­amino)­ethyl­carbamate with p-meth­oxy­phenyl­sulfonyl chloride. In the mol­ecule, two intra­molecular C—H⋯O hydrogen bonds are observed. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C—H⋯O hydrogen bonds, forming layers parallel to the bc plane....

  18. HPLC-MS测定白酒中氨基甲酸酯类农药残留%Determination of carbamates pesticides in liquor by HPLC/MS

    谭文渊; 袁东; 付大友; 李艳清; 王蓉

    2012-01-01

    A HPLC/MS method has been established for the determination of ten carbamates pesticides in liquor. The chromatographic conditions are as follows: Column of Phenomenex-Luna CN 100 A(250 mm×.6 mm×5 pm), and mobile phase was acetonitrile-water(20:80-80:20 within 40 minutes), flow rate was 1.0 mL/min, wavelength was 195 nm, column temperature was 25 ℃ and the injection volume was 20 μl.. MS conditions: Scanning range is 50-350 m/z, temperature of drying gas is 350 %, flow rate of drying gas is 8.0 mL/min, pressure of the evaporative gas is 275.86 kPa. The liquor samples were treated by SPE(solid phase extraction, NH2) and then concentrated by nitrogen-blow. Results showed that the standard curves of ten carbamates were linear over the quality range of 0.05-3 μg/mL, the correlation coefficient r were over 0.99. The average recovery of carbamates were 72.6%-97.6%, RSD were 2.6%-5.9%. Conclusion: this method was accurate, rapid, sensitive for the determination of carbamates pesticides in liquor by HPLC/MS.%建立了一种同时对白酒中10种氨基甲酸酯类农药残留的HPLC-MS测定方法。色谱条件:色谱柱Phenomenex-LunaCN100A(250mm×4.6mm×5μm),流动相乙腈-水(在40min内乙腈由20%变为80%),流速1.00mL/min,检测波长195nm,柱温25℃,进样量20μL。质谱条件:电喷雾离子源(ESI+源),扫描范围(m/z)为50~350,干燥气温度350℃,干燥气流速8.0mL/min,雾化气压力275.86kPa。样品制备:白酒样品用固相萃取处理后,氮吹浓缩,乙腈定容至2mL。结果表明,10种氨基甲酸酯类农药残留在0.05~3μg范围积线性关系良好,相关系数R2〉0.99。平均回收率在72.6%和97.6%,RSD在2.6%~5.9%之间。结论:方法灵敏度高、操作简便、结果准确,可用于酒样中痕量农药残留的含量测定。

  19. A novel and efficient strategy for the synthesis of various carbamates using carbamoyl chlorides under solvent-free and grinding conditions using microwave irradiation

    Hassan Zare; Mohammad Mehdi Ghanbari; Marzieh Jamali; Abdollah Aboodi

    2012-01-01

    We present an efficient,fast and simple strategy of generating the intermediate carbamoyl chlorides from secondary amines using stoichiometric amounts of bis(trichloromethyl)carbonate (BTC) in solution and solvent-free conditions with excellent yields.The results obtained showed the yield increasing on whether a base was used.Finally,an efficient and rapid synthesis of variety carbamate derivatives was developed by the reaction with a high variety of different alcohols,phenols,diols and this intermediate at room temperature with grinding and in solvent-free conditions under microwave irradiation.The presence of various safe bases is shown to be effective in reducing the reaction times,increasing the yields and easing purification.The present method does not involve any azardous phosgene.

  20. Putting muscle in DNA methylation

    James P Reddington; Richard R Meehan

    2011-01-01

    Over 25 years ago seminal experiments from the labs of Peter Jones and Harold Weintraub demonstrated that alteration in the DNA modification state underlie the myogenic conversion of fibroblast cell lines [1,2].This paved the way for the identification of myogenic helix-loop-helix (HLH) proteins in muscle differentiation,but the mechanism by which DNA methylation regulates muscle differentiation has remained elusive [3].

  1. 关于氨气提法尿素装置高压甲铵冷凝器配置的分析%Analysis Concerning Arrangement of High Pressure Carbamate Condenser in Urea Plant by Ammonia Stripping Method

    夏炎华; 孙喜; 刘金亮

    2013-01-01

    意大利斯那姆氨气提法工艺自上世纪80年代末期引入我国以来,国内已有近30套氨气提法尿素装置,但国内的氨气提法尿素装置全部采用的是传统的单高压甲铵冷凝器流程,而在国外双高压甲铵汽凝器流程已广泛使用。介绍了单高压甲铵冷凝流程和双高压甲铵冷凝器流程的工艺特点;对比了2种流程的蒸汽平衡及中压蒸汽消耗。结果表明,采用双高压甲铵冷凝流程配置,其吨尿素中压蒸汽消耗比单高压甲铵冷凝器流程低150.31 kg ,节能效果明显。%Since the Italian Snamprogetti ammonia stripping method process has been imported into China at end stage in 1980, there were almost 30 sets of urea plants with ammonia stripping method in China , but in all inland urea plants with ammonia stripping method , the traditional process with sin-gle high pressure carbamate condenser was fully adopted , and the process with double high pressure carbamate condensers was widely used in foreign countries.Author has introduced the process features of single high pressure carbamate condenser and double high pressure carbamate condensers; has compared the steam balance and steam consume for the two kinds of processes.Result indicates that using arrangement of process with double high pres-sure carbamate condensers, the consume of middle pressure steam per ton of urea is 150.31kg lower than that in process with single high pressure carba-mate condenser, the effect for saving energy is obvious.

  2. Combustion characterization of methylal in reciprocating engines

    Dodge, L.; Naegeli, D. [Southwest Research Institute, San Antonio, TX (United States)

    1994-06-01

    Methylal, CH{sub 3}OCH{sub 2}OCH{sub 3}, also known as dimethoxy-methane, is unique among oxygenates in that it has a low autoignition temperature, no carbon-carbon bonds, and is soluble in middle distillate fuels. Because of these properties, methylal has been shown to be a favorable fuel additive for reducing smoke in diesel engines. Recent measurements of ignition delay times indicate that methylal has a cetane number in the range of 45-50, which is compatible with diesel fuels. Engine tests have shown that adding methylal to diesel fuel significantly reduces smoke emissions. Gaseous emissions and combustion efficiencies obtained with methylal/diesel fuel blends remain essentially the same as those measured using neat diesel fuel. Lubricity measurements of methylal/diesel fuel blends with a ball on cylinder lubrication evaluator (BOCLE) show that methylal improves the lubricity of diesel fuel. Even though additions of methylal lower the fuel viscosity, the results of the BOCLE tests indicate that the methylal/diesel fuel blends cause less pump wear than neat diesel fuel. The one drawback is that methylal has a low boiling point (42{degrees}C) and a relatively high vapor pressure. As a result, it lowers the flash point of diesel fuel and causes a potential fuel tank flammability hazard. One solution to this increased volatility is to make polyoxymethylenes with the general formula of CH{sub 3}O(CH{sub 2}O){sub x}CH{sub 3} where x > 2. The molecules are similar to methylal, but have higher molecular weights and thus higher viscosities and substantially lower vapor pressures. Therefore, their flash points will be compatible with regular diesel fuel. The polyoxymethylenes are expected to have combustion properties similar to methylal. It is theorized that by analogy with hydrocarbons, the ignition quality (i.e., cetane number) of the polyoxymethylenes will be better than that of methylal.

  3. Wp specific methylation of highly proliferated LCLs

    The epigenetic regulation of viral genes may be important for the life cycle of EBV. We determined the methylation status of three viral promoters (Wp, Cp, Qp) from EBV B-lymphoblastoid cell lines (LCLs) by pyrosequencing. Our pyrosequencing data showed that the CpG region of Wp was methylated, but the others were not. Interestingly, Wp methylation was increased with proliferation of LCLs. Wp methylation was as high as 74.9% in late-passage LCLs, but 25.6% in early-passage LCLs. From two Burkitt's lymphoma cell lines, Wp specific hypermethylation was also found (>80%). Interestingly, the expression of EBNA2 gene which located directly next to Wp was associated with its methylation. Our data suggested that Wp specific methylation may be important for the indicator of the proliferation status of LCLs, and the epigenetic viral gene regulation of EBNA2 gene by Wp should be further defined possibly with other biological processes

  4. An Integrated Workflow for DNA Methylation Analysis

    Pingchuan Li; Feray Demirci; Gayathri Mahalingam; Caghan Demirci; Mayumi Nakano; Blake C.Meyers

    2013-01-01

    The analysis of cytosine methylation provides a new way to assess and describe epigenetic regulation at a whole-genome level in many eukaryotes.DNA methylation has a demonstrated role in the genome stability and protection,regulation of gene expression and many other aspects of genome function and maintenance.BS-seq is a relatively unbiased method for profiling the DNA methylation,with a resolution capable of measuring methylation at individual cytosines.Here we describe,as an example,a workflow to handle DNA methylation analysis,from BS-seq library preparation to the data visualization.We describe some applications for the analysis and interpretation of these data.Our laboratory provides public access to plant DNA methylation data via visualization tools available at our "Next-Gen Sequence" websites (http://mpss.udel.edu),along with small RNA,RNA-seq and other data types.

  5. Vibrational Spectroscopy of Methyl benzoate

    Maiti, Kiran Sankar

    2014-01-01

    Methyl benzoate (MB) is studied as a model compound for the development of new IR pulse schemes with possible applicability to biomolecules. Anharmonic vibrational modes of MB are calculated on different level (MP2, SCS, CCSD(T) with varying basis sets) ab-initio PESs using the vibrational self-consistent field (VSCF) method and its correlation corrected extensions. Dual level schemes, combining different quantum chemical methods for diagonal and coupling potentials, are systematically studied and applied successfully to reduce the computational cost. Isotopic substitution of {\\beta}-hydrogen by deuterium is studied to obtain a better understanding of the molecular vibrational coupling topology.

  6. Curtius rearrangement reactions of 3-(4-azidocarbonyl) phenylsydnone. Synthesis of 4-(sydnon-3-yl) phenyl carbamates, N-aryl-N'-[4-(sydnon-3-yl)] phenyl ureas and their antimicrobial and insecticidal activities

    P R Latthe; P S Shinge; Bharati V Badami; P B Patil; S N Holihosur

    2006-05-01

    3-[4-(Azidocarbonyl)]phenylsydnone (2) obtained from 3-(4-hydrazinocarbonyl) phenylsydnone (1) on Curtius rearrangement with alcohols, water and amines afforded the corresponding carbamates (3a-h), 4,4'-(sydnone-3-yl) diphenyl urea (4) and 4-(heterocyclyl)phenyl ureas (5a-l). Compounds (5a-l) on one-pot ring conversion yielded the 1,3,4-oxadiazolin-2-one derivatives (6a-l), which on reaction with N2H4 gave the 4-amino-1,2,4-triazolin-3-ones (7a-l). All these compounds exhibited moderate antimicrobial activity against the few microbes tested. The carbamates have been found to be more toxic against fourth instar larvae of Aedes aegypti, in particular, the -butyl derivative (3e).

  7. Hypoxic radiosensitization by the antimicrobial methyl paraben

    Jacobs, G.P.; Sade, N.

    1984-08-01

    The antimicrobial preservative, methyl paraben (methyl-4-hydroxybenzoate) sensitizes anoxic buffered suspensions of Staphylococcus aureus to gamma-radiation. The maximal response at an 0.5 mM concentration represents a 150 percent increase in response over that for deoxygenated suspensions without additive, and 80 percent of the response for aerated suspensions alone. Methyl paraben is not toxic to the test organism under the present test conditions.

  8. Hypoxic radiosensitization by the antimicrobial methyl paraben

    The antimicrobial preservative, methyl paraben (methyl-4-hydroxybenzoate) sensitizes anoxic buffered suspensions of Staphylococcus aureus to gamma-radiation. The maximal response at an 0.5 mM concentration represents a 150 percent increase in response over that for deoxygenated suspensions without additive, and 80 percent of the response for aerated suspensions alone. Methyl paraben is not toxic to the test organism under the present test conditions

  9. Relaxation processes in aromatic methyl groups

    A range of compounds with methyl groups disposed ortho and peri on heteroaromatic frameworks have been prepared, and T1 values and methyl-methyl Overhauser effects measured for them. Most of the nuclear Overhauser effect values were ≤6%, but two examples of methyls flanked by two others exhibited values of 9% (6-hydroxy-4,4,5,7-tetramethyl-3,4-dihydro-2H-benzopyran -2-one) and 15% (1,4,5,8,9-pentamethylcarbazole). 19 refs., 1tab

  10. Influence of DNA methylation on transgene expression

    2001-01-01

    DNA methylation plays an important role in gene expression in eukaryote. But DNA methylation of transgene usually leads to target gene silencing in plant genetic engineering. In this research, reporter gene b-glu- curonidase (GUS) gene (uidA) was introduced into tobaccos via Agrobacterium-mediated transformation method, and the foreign uidA gene became inactive in some transgenic tobaccos. No mRNA of uidA was detected in these plants by Northern blotting analysis, and DNA methylation of promoter region was found. The results indicated that gene silencing might be caused by DNA methylation of promoter.

  11. DNA Methylation Landscapes of Human Fetal Development.

    Slieker, Roderick C; Roost, Matthias S; van Iperen, Liesbeth; Suchiman, H Eka D; Tobi, Elmar W; Carlotti, Françoise; de Koning, Eelco J P; Slagboom, P Eline; Heijmans, Bastiaan T; Chuva de Sousa Lopes, Susana M

    2015-10-01

    Remodelling the methylome is a hallmark of mammalian development and cell differentiation. However, current knowledge of DNA methylation dynamics in human tissue specification and organ development largely stems from the extrapolation of studies in vitro and animal models. Here, we report on the DNA methylation landscape using the 450k array of four human tissues (amnion, muscle, adrenal and pancreas) during the first and second trimester of gestation (9,18 and 22 weeks). We show that a tissue-specific signature, constituted by tissue-specific hypomethylated CpG sites, was already present at 9 weeks of gestation (W9). Furthermore, we report large-scale remodelling of DNA methylation from W9 to W22. Gain of DNA methylation preferentially occurred near genes involved in general developmental processes, whereas loss of DNA methylation mapped to genes with tissue-specific functions. Dynamic DNA methylation was associated with enhancers, but not promoters. Comparison of our data with external fetal adrenal, brain and liver revealed striking similarities in the trajectory of DNA methylation during fetal development. The analysis of gene expression data indicated that dynamic DNA methylation was associated with the progressive repression of developmental programs and the activation of genes involved in tissue-specific processes. The DNA methylation landscape of human fetal development provides insight into regulatory elements that guide tissue specification and lead to organ functionality. PMID:26492326

  12. Métathèse croisée d'alcènes contenant des N-hétéroaryles. Trifluorométhylation d'ène-carbamates cycliques et dérivés

    Lafaye, Kevin

    2015-01-01

    Has now been applied to the synthesis of a wide range of compounds such as polymers, petrochemicals, pharmaceuticals and naturals compounds. A large range of functional groups are well tolerated including alcohols, amides, carbamates and sulfonamides. However, some limitations still have to be overcome Olefin metathesis has emerged has one of the most efficient carbon-carbon bond forming reaction and such as rich N-heteroaryles which are probably causing desactivation of the ruthenium catalys...

  13. Determination of Seven Carbamates Residues in Vegetable by HPLC%高效液相色谱法测定蔬菜中7种氨基甲酸酯类农药残留研究

    王缇; 万妮

    2012-01-01

    [Objective] The aim was to establish an analysis method of carbamates residues. [ Method] The residues of aldiearb sulfone, alrli-carb sulfoxide, methomy), 3-hydroxy-carbofuran, aldiearb, carbofuran and carbryl in vegetable were determined by HPLC with fluorescence detector and post-column derivation, furthermore the fortified recoveries of seven carbamates in vegetable at 0.05, 0.10 and 0. 50 mg/kg were determined. [ Result] The recoveries of seven carbamates in vegetable ranged from 74.6% to 107. 6% , and the precision was less than 10%. [ Conclusion] The method is suitable for the determination of carbamates residues in Chinese cabbage, cucumber, tomato, pepper and celery.%[目的]建立一种氨基甲酸酯类农药残留分析方法.[方法]对市场上蔬菜随机抽样,采用配荧光检测器和柱后衍生系统的高效液相色谱议测定了蔬菜中涕灭威砜、涕灭威亚砜、灭多威、3-羟基克百威、涕灭威、克百威、甲萘威7种氨基甲酸酯类农药的多残留,对每种农药进行了3种不同浓度(0.05、0.10、0.50 mg/kg)的添加回收率试验.[结果]蔬菜中7种农药的回收率在74.6% ~ 107.6%,精密度在10%以内.[结论]该方法可用于大白菜、黄瓜、番茄、辣椒、芹菜等样品中氨基甲酸酯类农药残留分析.

  14. 同位素稀释-GC/MS法测定腐乳中氨基甲酸乙酯含量%Determination of ethyl carbamate in fermented bean curd by GC/MS with isotopic dilution

    王立媛; 吴平谷; 张晶; 汤鋆; 赵永信

    2011-01-01

    Objective:To establish a method for determination of ethyl carbamate in fermented bean curd by isotopic dilution -gas chromatograph - mass spectrometry ( GC/MS). Methods: Ethyl carbamate was determined by gas chromatography -mass spectrometry in selection ion mode after the samples were spiked with D5 - ethyl carbamate and purified by C18 and diatomite solid phase extraction column. Results: The recovery rates were 89% -99% and RSD < 10% , the limit of determination was 2.0 ug/kg. Conclusion: The method is sensitive, accurate and could be used for determination of ethyl carbamate in fermented bean curd.%目的:建立了一种用于腐乳中氨基甲酸乙酯含量的同位素稀释-气相色谱-质谱联用检测方法.方法:采用D5-氨基甲酸乙酯同位素稀释技术,C18和硅藻土固相萃取净化样品,然后用GC/MS测定样品中氨基甲酸乙酯.结果:该方法在腐乳中氨基甲酸乙酯的加标回收率在89%~ 99%之间,相对标准偏差(RSD)小于10%,最低检测限达到2.0μg/kg.结论:方法净化效果好,检测灵敏度、准确度均满足检测要求,可作为腐乳中氨基甲酸乙酯含量检测的确证方法.

  15. A genome-wide methylation study on obesity Differential variability and differential methylation

    Xu, Xiaojing; Su, Shaoyong; Barnes, Vernon A.; De Miguel, Carmen; Pollock, Jennifer; Ownby, Dennis; Shi, Huidong; Zhu, Haidong; Snieder, Harold; Wang, Xiaoling

    2013-01-01

    Besides differential methylation, DNA methylation variation has recently been proposed and demonstrated to be a potential contributing factor to cancer risk. Here we aim to examine whether differential variability in methylation is also an important feature of obesity, a typical non-malignant common

  16. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    2010-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  17. Methylation Linear Discriminant Analysis (MLDA for identifying differentially methylated CpG islands

    Vass J Keith

    2008-08-01

    Full Text Available Abstract Background Hypermethylation of promoter CpG islands is strongly correlated to transcriptional gene silencing and epigenetic maintenance of the silenced state. As well as its role in tumor development, CpG island methylation contributes to the acquisition of resistance to chemotherapy. Differential Methylation Hybridisation (DMH is one technique used for genome-wide DNA methylation analysis. The study of such microarray data sets should ideally account for the specific biological features of DNA methylation and the non-symmetrical distribution of the ratios of unmethylated and methylated sequences hybridised on the array. We have therefore developed a novel algorithm tailored to this type of data, Methylation Linear Discriminant Analysis (MLDA. Results MLDA was programmed in R (version 2.7.0 and the package is available at CRAN 1. This approach utilizes linear regression models of non-normalised hybridisation data to define methylation status. Log-transformed signal intensities of unmethylated controls on the microarray are used as a reference. The signal intensities of DNA samples digested with methylation sensitive restriction enzymes and mock digested are then transformed to the likelihood of a locus being methylated using this reference. We tested the ability of MLDA to identify loci differentially methylated as analysed by DMH between cisplatin sensitive and resistant ovarian cancer cell lines. MLDA identified 115 differentially methylated loci and 23 out of 26 of these loci have been independently validated by Methylation Specific PCR and/or bisulphite pyrosequencing. Conclusion MLDA has advantages for analyzing methylation data from CpG island microarrays, since there is a clear rational for the definition of methylation status, it uses DMH data without between-group normalisation and is less influenced by cross-hybridisation of loci. The MLDA algorithm successfully identified differentially methylated loci between two classes of

  18. Methyl 3-(Quinolin-2-ylindolizine-1-carboxylate

    Roumaissa Belguedj

    2015-12-01

    Full Text Available A novel compound, methyl 3-(quinolin-2-ylindolizine-1-carboxylate (2 has been synthesized by cycloaddition reaction of 1-(quinolin-2-ylmethylpyridinium ylide (1 with methyl propiolate in presence of sodium hydride in THF. The structure of this compound was established by IR, 1H-NMR, 13C-NMR and MS data

  19. DNA Methylation Modulates Nociceptive Sensitization after Incision

    Sun, Yuan; Sahbaie, Peyman; Liang, DeYong; Li, Wenwu; Shi, Xiaoyou; Kingery, Paige; Clark, J. David

    2015-01-01

    DNA methylation is a key epigenetic mechanism controlling DNA accessibility and gene expression. Blockade of DNA methylation can significantly affect pain behaviors implicated in neuropathic and inflammatory pain. However, the role of DNA methylation with regard to postoperative pain has not yet been explored. In this study we sought to investigate the role of DNA methylation in modulating incisional pain and identify possible targets under DNA methylation and contributing to incisional pain. DNA methyltranferase (DNMT) inhibitor 5-Aza-2′-deoxycytidine significantly reduced incision-induced mechanical allodynia and thermal sensitivity. Aza-2′-deoxycytidine also reduced hindpaw swelling after incision, suggesting an anti-inflammatory effect. Global DNA methylation and DNMT3b expression were increased in skin after incision, but none of DNMT1, DNMT3a or DNMT3b was altered in spinal cord or DRG. The expression of proopiomelanocortin Pomc encoding β-endorphin and Oprm1 encoding the mu-opioid receptor were upregulated peripherally after incision; moreover, Oprm1 expression was further increased under DNMT inhibitor treatment. Finally, local peripheral injection of the opioid receptor antagonist naloxone significantly exacerbated incision-induced mechanical hypersensitivity. These results suggest that DNA methylation is functionally relevant to incisional nociceptive sensitization, and that mu-opioid receptor signaling might be one methylation regulated pathway controlling sensitization after incision. PMID:26535894

  20. DMPD: TLR ignores methylated RNA? [Dynamic Macrophage Pathway CSML Database

    Full Text Available 16111629 TLR ignores methylated RNA? Ishii KJ, Akira S. Immunity. 2005 Aug;23(2):11...1-3. (.png) (.svg) (.html) (.csml) Show TLR ignores methylated RNA? PubmedID 16111629 Title TLR ignores methylate

  1. Protein methylation reactions in intact pea chloroplasts

    Post-translational protein methylation was investigated in Pisum sativum chloroplasts. Intact pea chloroplasts were incubated with (3H-methyl)-S-adenosylmethionine under various conditions. The chloroplasts were then separated into stromal and thylakoid fractions and analyzed for radioactivity transferred to protein. Light enhanced the magnitude of labeling in both fractions. One thylakoid polypeptide with an apparent molecular mass of 43 kDa was labeled only in the light. Several other thylakoid and stromal proteins were labeled in both light and dark-labeling conditions. Both base-labile methylation, carboxy-methylesters and base-stable groups, N-methylations were found. Further characterization of the methyl-transfer reactions will be presented

  2. Characterization by NMR of ozonized methyl linoleate

    Diaz, Maritza F. [National Center for Scientific Research, Havana (Cuba). Ozone Research Center. Dept. of Ozonized Substances]. E-mail: maritza.diaz@cnic.edu.cu; Gavin, Jose A. [University of the Laguna, Tenerife (Spain)

    2007-07-01

    In the present study ozonized methyl linoleate with peroxide index of 1,800 mmol-equiv kg{sup -1} was chemically characterized. Ozonation of methyl linoleate produced hydroperoxides, ozonides and aldehydes which were identified by {sup 1}H and {sup 13}C NMR two-dimensional. The standard methyl linoleate and ozonized methyl linoleate shown very similar {sup 1}H NMR spectra except for the signals at {delta} 9.7 and {delta} 9.6 that correspond to aldehydic hydrogen, {delta} 5.7 and {delta} 5.5 (olefinic signals from hydroperoxides) and {delta} 5.2 ppm (multiplet from ozonides methynic hydrogen). Other resonance assignments are based on the connectivities provided by the hydrogen scalar coupling constants. These results indicate that NMR spectroscopy can provide valuable information about the amount of formed oxygenated compounds in the ozonized methyl linoleate in order to use it to follow up ozone therapy and chemistry of ozonized vegetable oil. (author)

  3. A wide range kinetic modeling study of pyrolysis and oxidation of methyl butanoate and methyl decanoate. Note I: Lumped kinetic model of methyl butanoate and small methyl esters

    A lumped kinetic model of methyl butanoate pyrolysis and oxidation is presented and discussed in this work. The hierarchical approach first required the development and validation of sub-mechanisms of small esters such as methyl formate, methyl acrylate and methyl crotonate. A broad-ranging validation of the whole kinetic scheme of methyl butanoate oxidation was then carried out through comparisons with experimental data obtained in shock tube devices, plug flow and jet stirred reactors, rapid compression machines and premixed laminar flames. A detailed analysis of laminar flame speeds complements and extends this kinetic study. The lumped model predicts a wide range of experiments well, thus constituting a flexible and reliable kinetic scheme despite the reduced number of species involved. Moreover, this lumped approach and the proposed model lay the foundation for an extension to biodiesel fuel modeling.

  4. Radiation effects on DNA methylation in mice

    Effects of ionizing radiation on DNA methylation in liver, brain and spleen were examined by high performance liquid chromatography (HPLC). The total methylated cytosine level in the genome was reduced within 8 hours after 3.8 Gy of irradiation in liver of adult mice. But no appreciable effect was observed in brain and spleen. When mice were irradiated at newborn, liver DNA revealed no change in methylated cytosine level. Even though slight effects of radiation were detected in he methylation of the c-myc and c-fos genes, they were only temporary and no long-term effects were observed. These data suggest that the effect of radiation on DNA methylation in vivo is not prevailing a DNA damage, but rather influenced much through biological parameters. (author)

  5. Microemulsion Polymerization of Methyl Methacrylat

    2001-01-01

    The microemulsion polymerization of methyl methacrylate was studied. The effects of feeding modes on the structure and the properties of the obtained polymer microlatex were investigated by measuring the conversion, the transmittance and the refractive index of the latex, and by measuring the particle size, the molecular weight and the glass transition temperature (Tg) of the polymers. The results show that compared to the batch feeding mode, the semi-continuous feeding mode is more favorable to form a PMMA microlatex with a higher transmittance, a smaller particle size, a higher molecular weight and a higher Tg. And the obtained PMMA microlatex has a 30 %-40 % (mass fraction) polymer content, a 0.03 emulsifier/water weight ratio, a 0.05emulsifier/monomer weight ratio and a 17 nm average particle diameter, which is very important for the industrialization of the microemulsion polymerization technique.

  6. Estimation of the methylation pattern distribution from deep sequencing data

    Lin, Peijie; Forêt, Sylvain; Wilson, Susan R; Burden, Conrad J.

    2015-01-01

    Background Bisulphite sequencing enables the detection of cytosine methylation. The sequence of the methylation states of cytosines on any given read forms a methylation pattern that carries substantially more information than merely studying the average methylation level at individual positions. In order to understand better the complexity of DNA methylation landscapes in biological samples, it is important to study the diversity of these methylation patterns. However, the accurate quantific...

  7. Risk assessment of ethyl carbamate in Chinese rice wine among population in five provinces in China%中国5省市居民黄酒中氨基甲酸乙酯的风险评估

    刘爱东; 蒋定国; 周萍萍; 高秀芬; 李建文; 张磊; 刘兆平; 杨大进

    2015-01-01

    Objective To assess the health risk of exposure of ethyl carbamate from rice wine among population in five Chinese southeast provinces and municipalities.Methods The simple distribution method was introduced in dietary exposure assessment of ethyl carbamate derived from rice wine consumed by population aged 18 and above.Subsequently,their health risk assessment was conducted.The consumption data of rice wine from Chinese Nutrition and Health Survey (2002) and the ethyl carbamate concentrate data from a survey in 2010 and 2011 were adopted in dietary exposure assessment.Results The mean and maximum values of ethyl carbamate in rice wine sample were 0.103 and 0.498 mg/kg respectively.The average intake of ethyl carbamate and the margin of exposure (MOE) value among population aged 18 and above were 13.4 ng/kg BW per day and 22 388 respectively.In addition,the average intake of ethyl carbamate in rice wine of consumer only was 427.8 ng/kg BW per day.Therefore,the margin of exposure value was 701.Conclusion For the population aged 18 and above,the health risk caused by ethyl carbamate intake from rice wine was quite low,however,it was rather high among population who consume the rice wine in large quantities.%目的 对中国东南地区5省市居民黄酒中氨基甲酸乙酯暴露的健康风险进行评估.方法 利用2002年中国居民营养与健康状况调查5省市18岁及以上人群黄酒消费量数据,以及2010、2011年在5省市采集黄酒样品的检测结果,采用简单分布膳食暴露评估方法对人群经黄酒摄入氨基甲酸乙酯进行估计,并对造成的健康风险进行评估.结果 5省市黄酒中氨基甲酸乙酯的平均含量为0.103 mg/kg,最大值为0.498 mg/kg.18岁以上人群黄酒氨基甲酸乙酯平均暴露量为13.4 ng/kg BW,暴露限值为22 388.黄酒饮酒者氨基甲酸乙酯平均暴露量为427.8 ng/kg BW,暴露限值为701.结论 18岁及以上全部人群黄酒氨基甲酸乙酯暴露的健康风险较低,

  8. Graphene grafted silica-coated Fe3O4 nanocomposite as absorbent for enrichment of carbamates from cucumbers and pears prior to HPLC.

    Sun, Meng; Ma, Xiaoxing; Wang, Juntao; Wang, Weina; Wu, Qiuhua; Wang, Chun; Wang, Zhi

    2013-04-01

    In this paper, a novel graphene (G) grafted silica-coated Fe3O4 nanocomposite was fabricated by the chemical bonding of G onto the surface of silica-coated Fe3 O4 nanoparticles. Some carbamates (metolcarb, carbaryl, pirimicarb, and diethofencarb) in cucumber and pear samples were enriched by this nanocomposite prior to their determination by HPLC with UV detection. Experimental parameters that may affect the extraction efficiency were investigated. Under the optimum conditions, a linear response was achieved in the concentration range of 0.5-100.0 ng/g for metolcarb, carbaryl, and diethofencarb, and 1.0-100 ng/g for pirimicarb with the correlation coefficients (r) ranging from 0.9956 to 0.9984. The LOD (S/N = 3) of the method were found to be in the range from 0.08 to 0.2 ng/g. The RSDs were in the range from 2.4 to 5.8%. The results indicated that the G grafted silica-coated Fe3 O4 nanocomposite was stable and efficient for magnetic SPE and has a great application potential for the preconcentration of other organic pollutants from real samples. PMID:23404952

  9. Microwave accelerated selective Soxhlet extraction for the determination of organophosphorus and carbamate pesticides in ginseng with gas chromatography/mass spectrometry.

    Zhou, Ting; Xiao, Xiaohua; Li, Gongke

    2012-07-01

    Microwave accelerated selective Soxhlet extraction (MA-SSE), a novel selective extraction technique, was investigated in this study. A Soxhlet extraction system containing a glass filter was designed as an extractor. During the procedure of MA-SSE, both the target analytes and the interfering components were extracted from the sample into the extraction solvent enhanced by microwave irradiation. After the solvent flowed though the sorbent, the interfering components were adsorbed by the sorbent, and the target analytes remaining in the solvent were collected in the extraction bottle. No cleanup or filtration was required after extraction. The efficiency of the MA-SSE approach was demonstrated in the determination of organophosphorus and carbamate pesticide residues in ginseng by gas chromatography/mass spectrometry (GC/MS). Under the optimized conditions, low limits of detection (0.050-0.50 μg/kg) were obtained. The recoveries were in the range of 72.0-110.1% with relative standard deviations less than 7.1%. Because of the effect of microwave irradiation, MA-SSE showed significant advantage compared with other extraction techniques. The sorbent used in this study showed good cleanup ability. The mechanism of MA-SSE was demonstrated to be based on the rupture of the cell walls according to the structural changes of ginseng samples. On the basis of the results, MA-SSE as a simple and effective sample preparation technique for the analysis of pesticide residues in complex matrixes shows great promise. PMID:22686368

  10. Vibrational frequency analysis, FT-IR, DFT and M06-2X studies on tert-Butyl N-(thiophen-2yl)carbamate

    Sert, Yusuf; Singer, L. M.; Findlater, M.; Doğan, Hatice; Çırak, Ç.

    2014-07-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized tert-Butyl N-(thiophen-2yl)carbamate have been investigated. The experimental FT-IR (4000-400 cm-1) spectrum of the molecule in the solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and DFT/M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with the 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The vibrational frequencies have been assigned using potential energy distribution (PED) analysis by using VEDA 4 software. The computational optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with related literature results. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and are depicted.

  11. A DFT study on the functionalization of a BN nanosheet with PCsbnd X, (PC = phenyl carbamate, X = OCH3, CH3, NH2, NO2 and CN)

    Beheshtian, Javad; Soleymanabadi, Hamed; Peyghan, Ali Ahmadi; Bagheri, Zargham

    2013-03-01

    By using density functional theory calculations, we investigated the chemical functionalization of a BN nanosheet with different organo-azo derivatives including PCsbnd X, (PC = phenyl carbamate, X = OCH3, CH3, NH2, NO2 and CN) in terms of geometric, energetic, and electronic properties. Reaction energies have been calculated to be in the range of 0.19 to 0.35 eV which is augmented by increasing the electron withdrawing characteristic of the functional groups so that the relative magnitude order is sbnd NO2 > sbnd CN > sbnd OCH3 > sbnd CH3 > sbnd NH2. The chemical functionalization leads to a decrease in HOMO/LUMO energy gap of BN sheet especially after adsorption of PCsbnd NO2 by about 1.88 eV. Conduction level and Fermi level of the BN sheet are shifted to lower energies upon the functionalization of the sheet with PCsbnd NO2 and PCsbnd CN, thus, it leads to an increment in work function of the sheet, impeding the field electron emission.

  12. The Methylene Alkoxy Carbamate Self-Immolative Unit: Utilization for the Targeted Delivery of Alcohol-Containing Payloads with Antibody-Drug Conjugates.

    Kolakowski, Robert V; Haelsig, Karl T; Emmerton, Kim K; Leiske, Chris I; Miyamoto, Jamie B; Cochran, Julia H; Lyon, Robert P; Senter, Peter D; Jeffrey, Scott C

    2016-07-01

    A strategy for the conjugation of alcohol-containing payloads to antibodies has been developed and involves the methylene alkoxy carbamate (MAC) self-immolative unit. A series of MAC β-glucuronide model constructs were prepared to evaluate stability and enzymatic release, and the results demonstrated high stability at physiological pH in a substitution-dependent manner. All the MAC model compounds efficiently released alcohol drug surrogates under the action of β-glucuronidase. To assess the MAC technology for ADCs, the potent microtubule-disrupting agent auristatin E (AE) was incorporated through the norephedrine alcohol. Conjugation of the MAC β-glucuronide AE drug linker to the anti-CD30 antibody cAC10, and an IgG control antibody, gave potent and immunologically specific activities in vitro and in vivo. These studies validate the MAC self-immolative unit for alcohol-containing payloads within ADCs, a class that has not been widely exploited. PMID:27198854

  13. Utilization of charge-transfer complexation for the detection of carcinogenic substances in foods: Spectroscopic characterization of ethyl carbamate with some traditional π-acceptors

    Adam, Abdel Majid A.; Refat, Moamen S.; Saad, Hosam A.

    2013-04-01

    The study of toxic and carcinogenic substances in foods represents one of the most demanding areas in food safety, due to their repercussions for public health. One potentially toxic compound for humans is ethyl carbamate (EC). EC is a multi-site genotoxic carcinogen of widespread occurrence in fermented foods and alcoholic beverages. Structural and thermal stability of charge-transfer complexes formed between EC as a donor with quinol (QL), picric acid (PA), chloranilic acid (CLA), p-chloranil (p-CHL) and 1,3-dinitrobenzene (DNB) as acceptors were reported. Elemental analysis (CHN), electronic absorption spectra, photometric titration, IR, and 1H NMR spectra show that the interaction between EC and acceptors was stabilized by hydrogen bonding, via a 1:1 stoichiometry. Thermogravimetric (TG) analysis indicates that the formation of molecular CT complexes was stable, exothermic and spontaneous. Finally, the CT complexes were screened for their antibacterial and antifungal activities. The results indicated that the [(EC)(QL)] complex exhibited strong antimicrobial activities against various bacterial and fungal strains compared with standard drugs.

  14. Aberrant DNA methylation in cloned ovine embryos

    LIU Lei; HOU Jian; LEI TingHua; BAI JiaHua; GUAN Hong; AN XiaoRong

    2008-01-01

    By using the approach of immunofluorescence staining with an antibody against 5-methylcytosine (5MeC), the present study detected the DNA methylation patterns of cloned ovine embryos. The em-bryos derived from in vitro fertilization were also examined for reference purpose. The results showed that: (1) during the pre-implantation development, cloned embryos displayed a similar demethylation profile to the fertilized embryos; that is, the methylation level decreased to the lowest at 8-cell stage, and then increased again at morulae stage. However, methylation level was obviously higher in cloned embryos than in stage-matched fertilized embryos, especially at 8-cell stage and afterwards; (2) at blastocyst stage, the methylation pattern in cloned embryos was different from that in fertilized em-bryos. In cloned blastocyst, inner cell mass (ICM) exhibited a comparable level to trophectoderm cells (TE), while in in-vitro fertilized blastocyst the methylation level of ICM was lower than that of TE, which is not consistent with that reported by other authors. These results indicate that DNA methylation is abnormally reprogrammed in cloned embryos, implying that aberrant DNA methylation reprogramming may be one of the factors causing cloned embryos developmental failure.

  15. Imaging Histone Methylations in Living Animals.

    Sekar, Thillai V; Paulmurugan, Ramasamy

    2016-01-01

    Histone modifications (methylation, acetylation, phosphorylation, sumoylation, etc.,) are at the heart of cellular regulatory mechanisms, which control expression of genes in an orderly fashion and control the entire cellular regulatory networks. Histone lysine methylation has been identified as one of the several posttranslational histone modifications that plays crucial role in regulating gene expressions in facultative heterochromatic DNA regions while maintaining structural integrity in constitutive heterochromatic DNA regions. Since histone methylation is dysregulated in various cellular diseases, it has been considered a potential therapeutic target for drug development. Currently there is no simple method available to screen and preclinically evaluate drugs modulating this cellular process, we recently developed two different methods by adopting reporter gene technology to screen drugs and to preclinically evaluate them in living animals. Method detects and quantitatively monitors the level of histone methylations in intact cells, is of a prerequisite to screen small molecules that modulate histone lysine methylation. Here, we describe two independent optical imaging sensors developed to image histone methylations in cells and in living animals. Since we used standard PCR-based cloning strategies to construct different plasmid vectors shown in this chapter, we are not providing any details regarding the construction methods, instead, we focus on detailing various methods used for measuring histone methylation-assisted luciferase quantitation in cells and imaging in living animals. PMID:27424907

  16. DNA methylation analysis reveals distinct methylation signatures in pediatric germ cell tumors

    Aberrant DNA methylation is a prominent feature of many cancers, and may be especially relevant in germ cell tumors (GCTs) due to the extensive epigenetic reprogramming that occurs in the germ line during normal development. We used the Illumina GoldenGate Cancer Methylation Panel to compare DNA methylation in the three main histologic subtypes of pediatric GCTs (germinoma, teratoma and yolk sac tumor (YST); N = 51) and used recursively partitioned mixture models (RPMM) to test associations between methylation pattern and tumor and demographic characteristics. We identified genes and pathways that were differentially methylated using generalized linear models and Ingenuity Pathway Analysis. We also measured global DNA methylation at LINE1 elements and evaluated methylation at selected imprinted loci using pyrosequencing. Methylation patterns differed by tumor histology, with 18/19 YSTs forming a distinct methylation class. Four pathways showed significant enrichment for YSTs, including a human embryonic stem cell pluripotency pathway. We identified 190 CpG loci with significant methylation differences in mature and immature teratomas (q < 0.05), including a number of CpGs in stem cell and pluripotency-related pathways. Both YST and germinoma showed significantly lower methylation at LINE1 elements compared with normal adjacent tissue while there was no difference between teratoma (mature and immature) and normal tissue. DNA methylation at imprinted loci differed significantly by tumor histology and location. Understanding methylation patterns may identify the developmental stage at which the GCT arose and the at-risk period when environmental exposures could be most harmful. Further, identification of relevant genetic pathways could lead to the development of new targets for therapy

  17. Dietary and lifestyle factors of DNA methylation.

    Lim, Unhee; Song, Min-Ae

    2012-01-01

    Lifestyle factors, such as diet, smoking, physical activity, and body weight management, are known to constitute the majority of cancer causes. Epigenetics has been widely proposed as a main mechanism that mediates the reversible effects of dietary and lifestyle factors on carcinogenesis. This chapter reviews human studies on potential dietary and lifestyle determinants of DNA methylation. Apart from a few prospective investigations and interventions of limited size and duration, evidence mostly comes from cross-sectional observational studies and supports some associations. Studies to date suggest that certain dietary components may alter genomic and gene-specific DNA methylation levels in systemic and target tissues, affecting genomic stability and transcription of tumor suppressors and oncogenes. Most data and supportive evidence exist for folate, a key nutritional factor in one-carbon metabolism that supplies the methyl units for DNA methylation. Other candidate bioactive food components include alcohol and other key nutritional factors of one-carbon metabolism, polyphenols and flavonoids in green tea, phytoestrogen, and lycopene. Some data also support a link of DNA methylation with physical activity and energy balance. Effects of dietary and lifestyle exposures on DNA methylation may be additionally modified by common genetic variants, environmental carcinogens, and infectious agents, an aspect that remains largely unexplored. In addition, growing literature supports that the environmental conditions during critical developmental stages may influence later risk of metabolic disorders in part through persistent programming of DNA methylation. Further research of these modifiable determinants of DNA methylation will improve our understanding of cancer etiology and may present certain DNA methylation markers as attractive surrogate endpoints for prevention research. Considering the plasticity of epigenetic marks and correlated nature of lifestyle factors, more

  18. Methylation – an uncommon modification of glycans*

    Staudacher, Erika

    2012-01-01

    A methyl group on a sugar residue is a rarely reported event. Until now this kind of modification has been found in the kingdom of animals only in worms and molluscs, whereas it is more frequently present in some species of bacteria, fungi, algae and plants, but not in mammals. The monosaccharides involved as well as the positions of the methyl groups on the sugar vary with the species. Methylation seems to play a role in some recognition events but details are still unknown. This review summ...

  19. Recognition of methylated DNA through methyl-CpG binding domain proteins

    Zou, Xueqing; Ma, Wen; Solov'yov, Ilia;

    2012-01-01

    DNA methylation is a key regulatory control route in epigenetics, involving gene silencing and chromosome inactivation. It has been recognized that methyl-CpG binding domain (MBD) proteins play an important role in interpreting the genetic information encoded by methylated DNA (mDNA). Although the...... function of MBD proteins has attracted considerable attention and is well characterized, the mechanism underlying mDNA recognition by MBD proteins is still poorly understood. In this article, we demonstrate that the methyl-CpG dinucleotides are recognized at the MBD-mDNA interface by two MBD arginines...... through an interplay of hydrogen bonding and cation-p interaction. Through molecular dynamics and quantum-chemistry calculations we investigate the methyl-cytosine recognition process and demonstrate that methylation enhances MBD-mDNA binding by increasing the hydrophobic interfacial area and by...

  20. Methylated Flavonoids From Artemisia Monosperma

    S. I. Ismail; Hammouda, F. M. [فايزة محمود حمودة; Rizk, A. M.; Hassan, N. M.

    1989-01-01

    Investigation of the flavonoid constituents of Artemisia monosperma resulted in the isolation and identification of four methylated flavonoids: quercetin 3,3',4'-trimethylether, diosmetin (luteolin 4'-methylether), 2',3,5'-trimethoxy-4',5,7-trihydroxyflavone and 2',5'-dimethoxy-3,4',5,7-tetrahydroxyflavone. أسفرت دراسة الفلافونيدات لنبات العادر عن فصل وتعريف أربعة مركبات هي : كيرستين 3،13،14 - تراي ميثيل إثير ، دايزموتين ( ليتيولين 14 - ميثيل أثير ) ، 12،3،15 - تراي ميثوكس - 14 ،5 ،7 - ترا...

  1. Prognostic CpG Methylation Biomarkers Identified by Methylation Array in Esophageal Squamous Cell Carcinoma Patients

    Kuo, I-Ying; Chang, Jia-Ming; Jiang, Shih-Sheng; Chen, Chung-Hsin; Chang, I-Shou; Sheu, Bor-Shyang; Lu, Pei-Jung; Chang, Wei-Lun; Lai, Wu-Wei; Wang, Yi-Ching

    2014-01-01

    Background: Esophageal squamous cell carcinoma (ESCC) is an aggressive cancer with poor prognosis. We aimed to identify a panel of CpG methylation biomarkers for prognosis prediction of ESCC patients. Methods: Illumina's GoldenGate methylation array, supervised principal components, Kaplan-Meier survival analyses and Cox regression model were conducted on dissected tumor tissues from a training cohort of 40 ESCC patients to identify potential CpG methylation biomarkers. Pyrosequencing quantit...

  2. MGMT promoter methylation in gliomas-assessment by pyrosequencing and quantitative methylation-specific PCR

    Håvik Annette

    2012-03-01

    Full Text Available Abstract Background Methylation of the O6-methylguanine-DNA methyltransferase (MGMT gene promoter is a favorable prognostic factor in glioblastoma patients. However, reported methylation frequencies vary significantly partly due to lack of consensus in the choice of analytical method. Method We examined 35 low- and 99 high-grade gliomas using quantitative methylation specific PCR (qMSP and pyrosequencing. Gene expression level of MGMT was analyzed by RT-PCR. Results When examined by qMSP, 26% of low-grade and 37% of high-grade gliomas were found to be methylated, whereas 97% of low-grade and 55% of high-grade gliomas were found methylated by pyrosequencing. The average MGMT gene expression level was significantly lower in the group of patients with a methylated promoter independent of method used for methylation detection. Primary glioblastoma patients with a methylated MGMT promoter (as evaluated by both methylation detection methods had approximately 5 months longer median survival compared to patients with an unmethylated promoter (log-rank test; pyrosequencing P = .02, qMSP P = .06. One third of the analyzed samples had conflicting methylation results when comparing the data from the qMSP and pyrosequencing. The overall survival analysis shows that these patients have an intermediate prognosis between the groups with concordant MGMT promoter methylation results when comparing the two methods. Conclusion In our opinion, MGMT promoter methylation analysis gives sufficient prognostic information to merit its inclusion in the standard management of patients with high-grade gliomas, and in this study pyrosequencing came across as the better analytical method.

  3. Homogalacturonan Methyl-Esterification and Plant Development

    Sebastian Wolf; Gregory Mouille; Jérome Pelloux

    2009-01-01

    The ability of a plant cell to expand is largely defined by the physical constraints imposed by its cell wall. Accordingly, cell wall properties have to be regulated during development. The pectic polysaccharide homogalacturonan is a major component of the plant primary walls. Biosynthesis and in muro modification of homogalacturonan have recently emerged as key determinants of plant development, controlling cell adhesion, organ development, and phyllo-tactic patterning. This review will focus on recent findings regarding impact of homogalacturonan content and methyl-esterification status of this polymer on plant life. De-methyl-esterification of homogalacturonan occurs through the action of the ubiquitous enzyme 'pectin methyl-esterase'. We here describe various strategies developed by the plant to finely tune the methyl-esterification status of homogalacturonan along key events of the plant lifecycle.

  4. Targeting DNA Methylation for Epigenetic Therapy

    Yang, Xiaojing; Lay, Fides; Han, Han; Jones, Peter A.

    2010-01-01

    DNA methylation patterns are established during embryonic development and faithfully copied through somatic cell divisions. Based on our understanding of DNA methylation and other interrelated epigenetic modifications, a comprehensive view of the epigenetic landscape and cancer epigenome is evolving. The cancer methylome is highly disrupted, making DNA methylation an excellent target for anti-cancer therapies. During the last few decades, an increasing number of drugs targeting DNA methylation have been developed in an effort to increase efficacy, stability and to decrease toxicity. The earliest and the most successful epigenetic drug to date, 5-Azacytidine, is currently recommended as the first-line treatment for high risk myelodysplastic syndromes (MDS) patients. Encouraging results from clinical trials have prompted further efforts to elucidate epigenetic alterations in cancer and subsequently develop new epigenetic therapies. This review delineates the latest cancer epigenetic models, recent discovery of hypomethylation agents and their application in the clinic. PMID:20846732

  5. Preparation of methyl-3H labelled dimethylnitrosamine

    Tritium labelled dimethylamine was prepared from benzalmethylimine in reaction with methyl-3H iodide followed by hydrolysis. The product was converted with sodium nitrite in glacial acetic acid into labelled dimethylnitrosamine. The radiochemical yield was 85%. (author)

  6. Copper Catalyzed Oceanic Methyl Halide Production

    Robin Kim, Jae Yun; Rhew, Robert

    2014-01-01

    Methyl halides are found in all of Earth’s biomes, produced naturally or through manmade means. Their presence in the atmosphere is problematic, as they catalyze depletion of stratospheric ozone. To understand the full environmental impact of these compounds, it is important to identify their chemical cycling processes. Iron increases methyl halide production in soils and oceans, yet copper’s influence remains unknown despite its similar chemical oxidation properties to iron. I experimentally...

  7. Histone H4 Lysine 20 methylation

    Jørgensen, Stine; Schotta, Gunnar; Sørensen, Claus Storgaard

    2013-01-01

    compaction. The distinct H4K20 methylation states are mediated by SET8/PR-Set7 that catalyses monomethylation of H4K20, whereas SUV4-20H1 and SUV4-20H2 enzymes mediate further H4K20 methylation to H4K20me2 and H4K20me3. Disruption of these H4K20-specific histone methyltransferases leads to genomic...

  8. Aberrant DNA methylation in cervical carcinogenesis

    Hui-Juan Yang

    2013-01-01

    Persistent infection with high-risk types of human papillomavirus(HPV) is known to cause cervical cancer; however,additional genetic and epigenetic alterations are required for progression from precancerous disease to invasive cancer.DNA methylation is an early and frequent molecular alteration in cervical carcinogenesis.In this review,we summarize DNA methylation within the HPV genome and human genome and identify its clinical implications.Methylation of the HPV long control region (LCR) and L1 gene is common during cervical carcinogenesis and increases with the severity of the cervical neoplasm.The L1 gene of HPV16 and HPV18 is consistently hypermethylated in invasive cervical cancers and can potentially be used as a clinical marker of cancer progression.Moreover,promoters of tumor suppressor genes (TSGs) involved in many cellular pathways are methylated in cervical precursors and invasive cancers.Some are associated with squamous cell carcinomas,and others are associated with adenocarcinomas.Identification of methylated TSGs in Pap smear could be an adjuvant test in cervical cancer screening for triage of women with high-risk HPV,atypical squamous cells of undetermined significance,or low grade squamous intraepithelial lesion (LSIL).However,consistent panels must be validated for this approach to be translated to the clinic.Furthermore,reversion of methylated TSGs using demethylating drugs may be an alternative anticancer treatment,but demethylating drugs without toxic carcinogenic and mutagenic properties must be identified and validated.

  9. DNA Methylation Biomarkers: Cancer and Beyond

    Thomas Mikeska

    2014-09-01

    Full Text Available Biomarkers are naturally-occurring characteristics by which a particular pathological process or disease can be identified or monitored. They can reflect past environmental exposures, predict disease onset or course, or determine a patient’s response to therapy. Epigenetic changes are such characteristics, with most epigenetic biomarkers discovered to date based on the epigenetic mark of DNA methylation. Many tissue types are suitable for the discovery of DNA methylation biomarkers including cell-based samples such as blood and tumor material and cell-free DNA samples such as plasma. DNA methylation biomarkers with diagnostic, prognostic and predictive power are already in clinical trials or in a clinical setting for cancer. Outside cancer, strong evidence that complex disease originates in early life is opening up exciting new avenues for the detection of DNA methylation biomarkers for adverse early life environment and for estimation of future disease risk. However, there are a number of limitations to overcome before such biomarkers reach the clinic. Nevertheless, DNA methylation biomarkers have great potential to contribute to personalized medicine throughout life. We review the current state of play for DNA methylation biomarkers, discuss the barriers that must be crossed on the way to implementation in a clinical setting, and predict their future use for human disease.

  10. 酱油中氨基甲酸乙酯和氯丙醇含量调查与分析%Survey and analysis of ethyl carbamate and 3-chloro-1,2-propanediol (3-MCPD) in soy sauce

    王立媛; 吴平谷; 张晶; 汤鋆; 赵永信

    2012-01-01

    Objective:To investigate the levels of 3 - chloro - 1,2 - propanediol(3 - MCPD) and ethyl carbamate in soy sauce. Methods: The total 135 soy sauce samples were collected from big, middle - sized and small supermarkets and farmer's market respectively. The 3 - chloro - 1,2 - propanediol(3 - MCPD) and ethyl carbamate were measured by gas chromatography - mass spectrometry in selection ion mode, after the samples were coupled with D5 - ethyl carbamate and D5 - 3 - chloro -1,2- propanediol ( 3 - MCPD ) , and purified by diatomite solid phase extraction coulum. Results: The results showed that ethyl carbamate was detected in all samples ( 100% ) with the range from 1. 6 μg/kg to 80. 8 μg/kg,the 3 - chloro - 1,2 - propanediol( 3 - MCPD) was detected in 32.05% of the samples with the range from 5. 8 μg/kg to 379. 10 μg/kg. Conclusion: In this investigation, the ethyl carbamate was detected in all soy sauce samples, and the level of 3 - chloro - 1,2 - propanediol(3 - MCPD) was not pretty low, and the data obtained in our test can be the references for risk assessment of ethyl carbamate and 3 - chloro - 1 ,2 - propanediol in soy sauce.%目的:调查本地市售酱油中氯丙醇和氨基甲酸乙酯含量.方法:在本市大、中、小超市及农贸市场采集135份酱油,采用d5-3-氯-1,2-丙二醇、D5-氨基甲酸乙酯同位素稀释技术,硅藻土固相萃取净化样品,然后用GC/MS测定样品中氯丙醇和氨基甲酸乙酯.结果:135份酱油中氨基甲酸乙酯检出率100%,含量范围为1.6 μg/kg~80.8 μg/kg;氯丙醇检出率为32.05%,含量范围为5.8 μg/kg~ 379.10 μg/kg.结论:本次调查显示酱油中均存在氨基甲酸乙酯,氯丙醇检出含量也不低,为开展酱油中氨基甲酸乙酯和氯丙醇的风险评估提供了基础数据.

  11. 新型氨基甲酸乙酯人工抗原的分析表征方法研究%Analysis and Characterization of a Novel Artificial Antigen of Ethyl Carbamate

    郭明; 周伟; 周珊; 敬娇; 杨萍

    2013-01-01

    A novel artificial antigen of ethyl carbamate( EC) was synthesized by l-(3-dimethylaminopropyl)-3-ethyl carbon carbodiimide method, and ATR-FTIR was applied to the characterization of the coupling effects of EC and the secondary structure change of the carrier protein combined with fluorescence spectrometry. The coupling ratio of the hapten molecules with the carrier protein of the new artificial antigen of ethyl carbamate was determined by MALDI-TOF-MS together with UV spectroscopy and electrophoresis method. The results showed that the synthetic route of the design was reasonable and a new artificial antigen of ethyl carbamate was successfully prepared. There was a variation in the content of α-helix, β-sheet and β-turn of artificial antigen compared with the carrier protein molecules. The "fluorescence phase diagram" of the artificial antigen was conformed to transitional relations of linear types, in line with the "all or none" pattern. The results of charac?terization of the artificial antigen of ethyl carbamate by ATR-FTIR and MALDI-TOF-MS were consistent with that of using other spectroscopic methods and electrophoresis methods. The coupling ratio of the artificial anti?gen calculated is 15:1-19:1 and the titer of antiserum by mice immunized with EC was 1:25600. The results of this work may provide a useful reference for the techniques of preparation and characterization of the artifi?cial antigen of ethyl carbamate.%采用1-(3-二甲氨基丙基)-3-乙基碳二亚胺方法合成氨基甲酸乙酯(Ethyl carbamate,EC)新型人工抗原.将衰减全反射红外光谱法(ATR-FTIR)应用于人工合成抗原的表征分析,并结合荧光光谱分析EC人工抗原的偶联效果以及载体蛋白质分子的二级结构变化;通过质谱结合紫外光谱、电泳方法进行人工抗原的系统表征,计算新型人工抗原中半抗原分子与载体蛋白质分子的偶联比.结果表明:合成路线合理,成功获得了氨基甲酸乙酯新型人

  12. Research progress on toxicity and contamination of ethyl carbamate in fermented foods%发酵食品中氨基甲酸乙酯污染及其毒性研究进展

    崔霞; 苗虹; 赵云峰; 吴永宁

    2014-01-01

    氨基甲酸乙酯(ethyl carbamate, EC)是在食品发酵过程中产生的一种化学污染物,广泛存在于发酵食品和酒精饮料中。对于啮齿类动物,氨基甲酸乙酯是一种多位点致癌物,可以导致动物发生肺癌、淋巴癌、肝癌和皮肤癌等疾病。国际癌症研究机构(IARC)已将其认定为2A 级致癌物,鉴于其对人类具有潜在的致癌性,氨基甲酸乙酯污染已成为近年来国际社会高度关注的食品安全热点问题之一。本文总结了当前国内外氨基甲酸乙酯的研究现状,对其理化特性、代谢途径、毒性、在发酵食品中的污染情况及各国限量标准进行了综述。最后建议我国相关部门应积极开展氨基甲酸乙酯安全问题调查和研究,帮助企业改进生产工艺,建立国家限量标准,以利于与国际接轨,促进我国发酵食品相关工业长期健康发展。%Ethyl carbamate is a kind of chemical contaminants which is formed as a by-product of fermentation processes, with widespread occurrence in fermented foods and alcoholic beverages. For the rodent animal, ethyl carbamate is recognized as a multisite carcinogen, which can cause lung cancer, lymphatic cancer, liver cancer, skin cancer and other diseases in animals. Recently, International Agency for Research on Cancer (IARC) upgraded its classification of ethyl carbamate to group 2A. On considering of its potential carcinogenicity to humans, ethyl carbamate pollution has become one of the hot issues of food safety in the world. The present paper summarized the current status of research about ethyl carbamate, and gave a review from the following aspects: the contamination level in fermented foods, limits of each states, metabolic pathways, and toxicity and so on. Finally, we suggested the relation departments should carry out the food safety surveys and studies about EC actively. In order to meet the international standards and facilitate the long-term healthy development of

  13. Determination of 7 carbamate pesticides in water by solid phase extraction-gas chromatography%固相萃取-气相色谱法测定水中7种氨基甲酸酯农药

    周伦敏; 陆昱养; 何云亚

    2013-01-01

    目的:建立应用气相色谱-氮磷检测器结合固相萃取测定水中7种氨基甲酸酯农药的方法.方法:水样经ENVI-Carb固相萃取柱富集,以二氯甲烷+丙酮(1+1)洗脱,采用DB-1701毛细管柱和氮磷检测器进行检测.结果:7种氨基甲酸酯农药在DB-1701毛细管柱上均能得到很好分离,回收率在82.0%~101.5%,相对标准偏差为2.9%~10.5%.结论:本方法简便、快速、灵敏,可用于水中氨基甲酸酯农药的检测.%Objective:To establish a method for determination of 7 carbamate pesticides in water by gas chromatography-nitrogen phosphorus detector combined with solid-phase extraction.Methods:The target pesticides in water samples were enrichmented with ENVI-Carb solid phase extraction column,and eluted with dichloromethane and acetone(1 + 1),and separated with DB-1701 capillary column and detected with GC-NPD.Results:Seven carbamate pesticides could be well separated,the recovery rates were 82.0% ~ 101.5%,with the relative standard deviation of 2.9% ~ 10.5%.Conclusion:This method was simple,rapid and sensitive and it can be applied for analysis of carbamate pesticides in water.

  14. Optimized method for methylated DNA immuno-precipitation

    Carlos Guerrero-Bosagna; Per Jensen

    2015-01-01

    Methylated DNA immunoprecipitation (MeDIP) is one of the most widely used methods to evaluate DNA methylation on a whole genome scale, and involves the capture of the methylated fraction of the DNA by an antibody specific to methyl-cytosine. MeDIP was initially coupled with microarray hybridization to detect local DNA methylation enrichments along the genome. More recently, MeDIP has been coupled with next generation sequencing, which highlights its current and future applicability. In previo...

  15. DNA methylation and microRNAs in cancer

    Li, Xiang-Quan; Guo, Yuan-Yuan(Department of Physics, Shanxi University, Taiyuan, Shanxi 030006, China); Wei,, J.B.

    2012-01-01

    DNA methylation is a type of epigenetic modification in the human genome, which means that gene expression is regulated without altering the DNA sequence. Methylation and the relationship between methylation and cancer have been the focus of molecular biology researches. Methylation represses gene expression and can influence embryogenesis and tumorigenesis. In different tissues and at different stages of life, the level of methylation of DNA varies, implying a fundamental but distinct role f...

  16. Measurement of mercury methylation in lake water and sediment samples

    Biological mercury methylation was assayed by a new radiochemical technique in the water column and sediments of a mercury-contaminated lake. In 24 weeks during 1979, there were three episodes of methylating activity in surface floc and in water, each lasting 3 to 5 weeks. Periods of methylation in the water column coincided with surface sediment methylation and appeared to be related to overall microbial activity. Mercury was actively methylated in the presence of bound sulfide

  17. Methyl-CpG-binding domain sequencing reveals a prognostic methylation signature in neuroblastoma.

    Decock, Anneleen; Ongenaert, Maté; Cannoodt, Robrecht; Verniers, Kimberly; De Wilde, Bram; Laureys, Geneviève; Van Roy, Nadine; Berbegall, Ana P; Bienertova-Vasku, Julie; Bown, Nick; Clément, Nathalie; Combaret, Valérie; Haber, Michelle; Hoyoux, Claire; Murray, Jayne; Noguera, Rosa; Pierron, Gaelle; Schleiermacher, Gudrun; Schulte, Johannes H; Stallings, Ray L; Tweddle, Deborah A; De Preter, Katleen; Speleman, Frank; Vandesompele, Jo

    2016-01-12

    Accurate assessment of neuroblastoma outcome prediction remains challenging. Therefore, this study aims at establishing novel prognostic tumor DNA methylation biomarkers. In total, 396 low- and high-risk primary tumors were analyzed, of which 87 were profiled using methyl-CpG-binding domain (MBD) sequencing for differential methylation analysis between prognostic patient groups. Subsequently, methylation-specific PCR (MSP) assays were developed for 78 top-ranking differentially methylated regions and tested on two independent cohorts of 132 and 177 samples, respectively. Further, a new statistical framework was used to identify a robust set of MSP assays of which the methylation score (i.e. the percentage of methylated assays) allows accurate outcome prediction. Survival analyses were performed on the individual target level, as well as on the combined multimarker signature. As a result of the differential DNA methylation assessment by MBD sequencing, 58 of the 78 MSP assays were designed in regions previously unexplored in neuroblastoma, and 36 are located in non-promoter or non-coding regions. In total, 5 individual MSP assays (located in CCDC177, NXPH1, lnc-MRPL3-2, lnc-TREX1-1 and one on a region from chromosome 8 with no further annotation) predict event-free survival and 4 additional assays (located in SPRED3, TNFAIP2, NPM2 and CYYR1) also predict overall survival. Furthermore, a robust 58-marker methylation signature predicting overall and event-free survival was established. In conclusion, this study encompasses the largest DNA methylation biomarker study in neuroblastoma so far. We identified and independently validated several novel prognostic biomarkers, as well as a prognostic 58-marker methylation signature. PMID:26646589

  18. Estimativa da incerteza de medição em análise cromatográfica: abordagem sobre a quantificação de carbamato de etila em cachaça The measurement uncertainty estimation in chromatographic analisys: approach on the quantification of ethyl carbamate in " cachaça"

    Marcus Henrique Campino de la Cruz

    2010-01-01

    Full Text Available The measurement uncertainty is useful to estimate the confidence of analytical results. Nowadays, a result without the uncertainty statement cannot be considered reliable, but the scientific literature still lacks examples of the estimate of the measurement uncertainty. This paper presents a practical and reliable description of the measurement uncertainty estimation of the analytical determination of ethyl carbamate in cachaça by GC-IDMS. The isotope dilution technique (ID associated with GC-MS was used to improve the accuracy. The uncertainty estimated corresponds to 10% of the mass fraction of ethyl carbamate (115 ± 11 ng/g, which is in agreement with ppb level.

  19. Study on carbamate pesticides by capillary electrophoresis with laser-induced fluorescence detection%CE-LIF在氨基甲酸酯类农药研究中的应用

    杨玉林; 赵晓寅; 赵文杰; 周天舒

    2012-01-01

    用毛细管电泳激光诱导荧光检测法(CE-LIF),对灭除威(XMC)、混杀威(2,3,5-trime-thacarb)和灭虫威(mercaptodimethur)等3种氨基甲酸酯类农药进行了研究.在碱性条件下,氨基甲酸酯类农药水解产生甲胺并与荧光衍生试剂4-氯-7-硝基-2,1,3-苯并二唑(NBD-Cl)发生衍生化反应,产物经毛细管电泳激光诱导荧光检测法测定.对影响水解、衍生以及毛细电泳分离的因素如缓冲液酸度、浓度和衍生试剂的浓度等进行了详细讨论;在最佳条件下,3种农药的检出限分别可达3.0×10-9、1.0×10-9和3.0×10-9 mol/L,并测定了它们的水解速率常数及活化能.该方法不仅可对氨基甲酸酯类农药进行测定,同时也可用于对这类农药的一些理化常数的测定.%A sensitive and rapid capillary electrophoresis method with laser-induced fluorescence detection (CE-LIF) was developed for the determination of carbamate pesticides (including (3,5-dimethylphenyl) N-methylcarbamate (XMC), and mercaptodimethur). In alkaline solution, carbamate was hydrolyzed to methylamine, which can be derivatized by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-C1) and detected by CE-LIF. Several parameters which influence the hydrolysis, derivatization and electrophoresis separation, such as pH, concentration of buffer solution and concentration of NBD-C1, were investigated. The detection limits of the three carbamates were 3. 0×10-9, 1. 0 ×10-9 and 3. 0 ×10-9 mol/L, respectively. The proposed method was successfully employed to determine the rate constants and activation energies for carbamates hydrolysis.

  20. UPLC-MS/MS测定中药材中19种氨基甲酸酯农药残留量%Determination of Nineteen Carbamate Pesticides in Chinese Medicinal Materials by UPLC-MS/MS

    张燕; 杨钊; 金红宇; 孙磊; 李欣荣; 吴爱英

    2011-01-01

    OBJECTIVE To establish a method for the determination of 19 carbamate pesticides in Chinese medicinal materials by UPLC triple-quadrupole tandem mass spectrometer.METHODS The samples were determinated by multi-reactions monitoring (MRM) technology.The separation was performed on a Waters ACQUITY UPLC (R) BEH C18 column with acetonitrile -0.1% formic acid ( 1:1 ) with a flow rate of 0.2 mL min-1.Ion mode was set as ESI+.RESULTS The standard curves of the 19 carbamate pesticides showed good linearity over the concentration range of 1.0 - 100 μg · L-1 (r =0.994 7 -0.999 7), respectively.The LODs of 19 carbamate pesticides were in the range of 0.02 - 0.46 μg · L- 1 and the average recoveries were 73.2% - 119.7% at three levels.CONCLUSION The method is rapid, sensitive and suitable for the determination of 19 carbamate pesticides in Chinese medicinal materials.%目的 建立测定中药材中19种氨基甲酸酯农药残留量的超高效液相-串联四级杆质谱方法.方法 多反应监测模式测定,以Waters ACQUITY UPLC(R) BEH C18进行分离,乙腈-0.1%甲酸溶液(1:1),流速:0.2 mL·min-1.离子化模式:ESI+.结果 19种农药测定的线性范围在1.0~100.0 μg·L-1之间,r分别在0.994 7~0.999 7之间,检出质量浓度分别在0.02~0.46μg·L-1之间,3个水平的回收率分别在73.2%~119.7%之间.结论 该方法快速、准确、灵敏,可用于中药材中氨基甲酸酯类农药残留的测定.

  1. Determination of Neurotoxin b-ODAP and Non-protein Amino Acids in Lathyrus Sativus by High-Performance Liquid Chromatography with Precolumn Derivatization with 6-Amino quinolyl-N-hydroxysuccinimidyl Carbamate (AQC)

    2000-01-01

    A new method was developed for the quantitative determination of the neurotoxic non-protein amino acid, 3-N-oxalyl-L-2,3-diaminopropionic acid (b -ODAP), its nontoxic a -isomer and other non-protein amino acids in the plant samples of Lathyrus sativus after derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) by reversed-phase high-performance liquid chromatography (HPLC). 2-Amino butyric acid (ABA) was used as an internal standard. The RP HPLC detection limit for both isomers is 1.8 ng with good response linearity. The results are compared with a colorimetric method.

  2. The Stress Corrosion Characteristics of the High-Pressure Ammonium Carbamate Condenser E104 and It's Leakage Treatment%高压甲铵冷凝器 E104应力腐蚀特点及泄漏处理

    刘志勇; 朱建宇

    2014-01-01

    针对氨汽提法尿素装置高压甲铵冷凝器腐蚀的特点,结合高压甲铵冷凝器的运行状况,探讨查漏方案及对策,以及操作维护方面的注意事项。%Combining the corrosion characteristics of the high-pressure ammonium carbamate condenser E104 in the ammonia stripping urea plant with it's operation ,discuss the leakage detection method and countermeasures ,precautions of operation and maintenance .

  3. 液相色谱串联质谱法测定白酒中氨基甲酸乙酯的方法探讨%Determination of Ethyl Carbamate in White Spirit by Liquid Chromatography-tandem Mass Spectrometry

    吴宏萍; 杨红文; 魏云; 吴丽华; 薛锡佳; 张娇娇; 锁震南; 时玉英

    2015-01-01

    建立了直接测定白酒中氨基甲酸乙酯的液相色谱-串联质谱(LC-MS-MS)分析方法,采用Poroshell 120EC-C18色谱柱,以0.1%乙酸水溶液和乙腈为流动相(体积比9∶1)进行洗脱,流速为0.2mL/min;在电喷雾电离(ESI)正离子模式下,采用多重反应监测模式进行检测,线性范围为5~500μg/L;检出限为1μg/L,定量限为5μg/L;加标回收率为89%~106%,相对标准偏差均不大于3.9%。该法快捷、准确、重现性好。%A method for the direct determination of ethyl carbamate in White spirit was established by liquid chromatography with tandem mass spectrometry (LC-MS-MS).The LC separation was performed on a Poroshell 120 EC-C18 column (50mm × 3.0mm,2.7μm)by using 0.1%(v/v) acetic acid aqueous solution and acetonitrile as mobile phases (v/v 9∶1) at a flow rate of 0.2mL/min. The analytes were detected by tandem mass spectro-metry under the positive ion mode with the electrospray ionization (ESI) source and in the multiple reaction monitoring (MRM)mode. Under the optimized conditions ,the calibration curve was linear in the ranges of 5~500μg/L for the ethyl carbamate with the detection limits of 1μg/L and the limit of quantification of 5μg/L. The recoveries of the ethyl carbamate was in the range of 89%and 106%with the relative standard deviations not more than3.9%. The developed method is simple ,rapid and accurate, and suitable for the quality control of ethyl carbamate in White spirit.

  4. Erasure of CpG methylation in Arabidopsis alters patterns of histone H3 methylation in heterochromatin

    Tariq, M.; Saze, H.; Probst, A.; Lichota, Jacek; Habu, Y.; Paszkowski, JK.

    2003-01-01

    In mammals and plants, formation of heterochromatin is associated with hypermethylation of DNA at CpG sites and histone H3 methylation at lysine 9. Previous studies have revealed that maintenance of DNA methylation in Neurospora and Arabidopsis requires histone H3 methylation. A feedback loop from...... DNA methylation to histone methylation, however, is less understood. Its recent examination in Arabidopsis with a partial loss of function in DNA methyltransferase 1 (responsible for maintenance of CpG methylation) yielded conflicting results. Here we report that complete removal of CpG methylation in...

  5. Ethyl-bridged hybrid column as an efficient alternative for HPLC analysis of plasma amino acids by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate.

    Castellanos, Mar; Van Eendenburg, Cecile Van; Gubern, Carme; Sanchez, Juan M

    2016-09-01

    Conventional C18 silica columns have proven to be useful for the analysis of amino acids (AA) from protein hydrolysates but undesirable peak overlapping is usually found when analyzing body fluids given that a large number of AAs are present in the samples. As an alternative to silica packings, an ethyl-bridged packing for reversed-phase liquid chromatography of derivatized AAs with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) has been evaluated. The new packing material improves the separation efficiency allowing better separations when analyzing biological fluids. Moreover, this packing has advantages for routine AA analysis, such as a decrease in the total running time and an increase in the life-time of the columns. The pH of the mobile phase has a significant effect on the elution behavior of the AQC hydrolysis product (AMQ) and on the AA derivatives. It is not possible to elute AMQ before detecting the first AA derivative, which requires an accurate adjustment of the pH in the range of 5.30-5.35 to obtain good separation and resolution for the most polar compounds. Under the conditions proposed, it is possible to separate all AAs except the Gly-Gln pair, which is not a problem when hydrolyzed samples are analyzed. The AMQ-Ser pair requires either the use of a different mobile phase pH for its baseline separation or the use of fluorescence detection. Two different procedures for protein removal from plasma samples have been evaluated, solvent precipitation and ultrafiltration (UF) and it has been found that UF gives better results as no significant losses of AAs were observed. The validation of the proposed method with UV detection gives method detection limits in the range of 8-12μM, with repeatability values<8% (n=6) and inter-day precision in plasma samples ranging from 4 to 13% (n=4). PMID:27428457

  6. Global DNA methylation of ischemic stroke subtypes.

    Carolina Soriano-Tárraga

    Full Text Available Ischemic stroke (IS, a heterogeneous multifactorial disorder, is among the leading causes of mortality and long-term disability in the western world. Epidemiological data provides evidence for a genetic component to the disease, but its epigenetic involvement is still largely unknown. Epigenetic mechanisms, such as DNA methylation, change over time and may be associated with aging processes and with modulation of the risk of various pathologies, such as cardiovascular disease and stroke. We analyzed 2 independent cohorts of IS patients. Global DNA methylation was measured by luminometric methylation assay (LUMA of DNA blood samples. Univariate and multivariate regression analyses were used to assess the methylation differences between the 3 most common IS subtypes, large-artery atherosclerosis (LAA, small-artery disease (SAD, and cardio-aortic embolism (CE. A total of 485 IS patients from 2 independent hospital cohorts (n = 281 and n = 204 were included, distributed across 3 IS subtypes: LAA (78/281, 59/204, SAD (97/281, 53/204, and CE (106/281, 89/204. In univariate analyses, no statistical differences in LUMA levels were observed between the 3 etiologies in either cohort. Multivariate analysis, adjusted by age, sex, hyperlipidemia, and smoking habit, confirmed the lack of differences in methylation levels between the analyzed IS subtypes in both cohorts. Despite differences in pathogenesis, our results showed no global methylation differences between LAA, SAD, and CE subtypes of IS. Further work is required to establish whether the epigenetic mechanism of methylation might play a role in this complex disease.

  7. Elucidating the pathway for arsenic methylation

    Although biomethylation of arsenic has been studied for more than a century, unequivocal demonstration of the methylation of inorganic arsenic by humans occurred only about 30 years ago. Because methylation of inorganic arsenic activates it to more reactive and toxic forms, elucidating the pathway for the methylation of this metalloid is a topic of considerable importance. Understanding arsenic metabolism is of public health concern as millions of people chronically consume drinking water that contains high concentrations of inorganic arsenic. Hence, the focus of our research has been to elucidate the molecular basis of the steps in the pathway that leads from inorganic arsenic to methylated and dimethylated arsenicals. Here we describe a new S-adenosylmethionine (AdoMet)-dependent methyltransferase from rat liver cytosol that catalyzes the conversion of arsenite to methylated and dimethylated species. This 42-kDa protein has sequence motifs common to many non-nucleic acid methyltransferases and is closely related to methyltransferases of previously unknown function that have been identified by conceptual translations of cyt19 genes of mouse and human genomes. Hence, we designate rat liver arsenic methyltransferase as cyt19 and suggest that orthologous cyt19 genes encode an arsenic methyltransferase in the mouse and human genomes. Our studies with recombinant rat cyt19 find that, in the presence of an exogenous or a physiological reductant, this protein can catalyze the entire sequence of reactions that convert arsenite to methylated metabolites. A scheme linking cyt19 and thioredoxin-thioredoxin reductase in the methylation and reduction of arsenicals is proposed

  8. DNA methylation at hepatitis B viral integrants is associated with methylation at flanking human genomic sequences

    Watanabe, Yoshiyuki; Yamamoto, Hiroyuki; Oikawa, Ritsuko; Toyota, Minoru; Yamamoto, Masakazu; Kokudo, Norihiro; Tanaka, Shinji; Arii, Shigeki; Yotsuyanagi, Hiroshi; Koike, Kazuhiko; Itoh, Fumio

    2015-01-01

    Integration of DNA viruses into the human genome plays an important role in various types of tumors, including hepatitis B virus (HBV)–related hepatocellular carcinoma. However, the molecular details and clinical impact of HBV integration on either human or HBV epigenomes are unknown. Here, we show that methylation of the integrated HBV DNA is related to the methylation status of the flanking human genome. We developed a next-generation sequencing-based method for structural methylation analysis of integrated viral genomes (denoted G-NaVI). This method is a novel approach that enables enrichment of viral fragments for sequencing using unique baits based on the sequence of the HBV genome. We detected integrated HBV sequences in the genome of the PLC/PRF/5 cell line and found variable levels of methylation within the integrated HBV genomes. Allele-specific methylation analysis revealed that the HBV genome often became significantly methylated when integrated into highly methylated host sites. After integration into unmethylated human genome regions such as promoters, however, the HBV DNA remains unmethylated and may eventually play an important role in tumorigenesis. The observed dynamic changes in DNA methylation of the host and viral genomes may functionally affect the biological behavior of HBV. These findings may impact public health given that millions of people worldwide are carriers of HBV. We also believe our assay will be a powerful tool to increase our understanding of the various types of DNA virus-associated tumorigenesis. PMID:25653310

  9. GSH2 promoter methylation in pancreatic cancer analyzed by quantitative methylation-specific polymerase chain reaction

    GAO, FEI; HUANG, HAO-JIE; GAO, JUN; LI, ZHAO-SHEN; MA, SHU-REN

    2015-01-01

    Tumor suppressor gene silencing via promoter hypermethylation is an important event in pancreatic cancer pathogenesis. Aberrant DNA hypermethylation events are highly tumor specific, and may provide a diagnostic tool for pancreatic cancer patients. The objective of the current study was to identify novel methylation-related genes that may potentially be used to establish novel therapeutic and diagnostic strategies against pancreatic cancer. The methylation status of the GS homeobox 2 (GSH2) gene was analyzed using the sodium bisulfite sequencing method. The GSH2 methylation ratio was examined in primary carcinomas and corresponding normal tissues derived from 47 patients with pancreatic cancer, using quantitative methylation-specific polymerase chain reaction. Methylation ratios were found to be associated with the patient's clinicopathological features. GSH2 gene methylation was detected in 26 (55.3%) of the 47 pancreatic cancer patients, indicating that it occurs frequently in pancreatic cancer. A significant association with methylation was observed for tumor-node-metastasis stage (P=0.031). GSH2 may be a novel methylation-sensitive tumor suppressor gene in pancreatic cancer and may be a tumor-specific biomarker of the disease. PMID:26171036

  10. Methylation plotter: a web tool for dynamic visualization of DNA methylation data.

    Mallona, Izaskun; Díez-Villanueva, Anna; Peinado, Miguel A

    2014-01-01

    Methylation plotter is a Web tool that allows the visualization of methylation data in a user-friendly manner and with publication-ready quality. The user is asked to introduce a file containing the methylation status of a genomic region. This file can contain up to 100 samples and 100 CpGs. Optionally, the user can assign a group for each sample (i.e. whether a sample is a tumoral or normal tissue). After the data upload, the tool produces different graphical representations of the results following the most commonly used styles to display this type of data. They include an interactive plot that summarizes the status of every CpG site and for every sample in lollipop or grid styles. Methylation values ranging from 0 (unmethylated) to 1 (fully methylated) are represented using a gray color gradient. A practical feature of the tool allows the user to choose from different types of arrangement of the samples in the display: for instance, sorting by overall methylation level, by group, by unsupervised clustering or just following the order in which data were entered. In addition to the detailed plot, Methylation plotter produces a methylation profile plot that summarizes the status of the scrutinized region, a boxplot that sums up the differences between groups (if any) and a dendrogram that classifies the data by unsupervised clustering. Coupled with this analysis, descriptive statistics and testing for differences at both CpG and group levels are provided. The implementation is based in R/shiny, providing a highly dynamic user interface that generates quality graphics without the need of writing R code. Methylation plotter is freely available at http://gattaca.imppc.org:3838/methylation_plotter/. PMID:25260021

  11. Prognostic DNA Methylation Markers for Prostate Cancer

    Siri H. Strand

    2014-09-01

    Full Text Available Prostate cancer (PC is the most commonly diagnosed neoplasm and the third most common cause of cancer-related death amongst men in the Western world. PC is a clinically highly heterogeneous disease, and distinction between aggressive and indolent disease is a major challenge for the management of PC. Currently, no biomarkers or prognostic tools are able to accurately predict tumor progression at the time of diagnosis. Thus, improved biomarkers for PC prognosis are urgently needed. This review focuses on the prognostic potential of DNA methylation biomarkers for PC. Epigenetic changes are hallmarks of PC and associated with malignant initiation as well as tumor progression. Moreover, DNA methylation is the most frequently studied epigenetic alteration in PC, and the prognostic potential of DNA methylation markers for PC has been demonstrated in multiple studies. The most promising methylation marker candidates identified so far include PITX2, C1orf114 (CCDC181 and the GABRE~miR-452~miR-224 locus, in addition to the three-gene signature AOX1/C1orf114/HAPLN3. Several other biomarker candidates have also been investigated, but with less stringent clinical validation and/or conflicting evidence regarding their possible prognostic value available at this time. Here, we review the current evidence for the prognostic potential of DNA methylation markers in PC.

  12. Prognostic DNA methylation markers for prostate cancer.

    Strand, Siri H; Orntoft, Torben F; Sorensen, Karina D

    2014-01-01

    Prostate cancer (PC) is the most commonly diagnosed neoplasm and the third most common cause of cancer-related death amongst men in the Western world. PC is a clinically highly heterogeneous disease, and distinction between aggressive and indolent disease is a major challenge for the management of PC. Currently, no biomarkers or prognostic tools are able to accurately predict tumor progression at the time of diagnosis. Thus, improved biomarkers for PC prognosis are urgently needed. This review focuses on the prognostic potential of DNA methylation biomarkers for PC. Epigenetic changes are hallmarks of PC and associated with malignant initiation as well as tumor progression. Moreover, DNA methylation is the most frequently studied epigenetic alteration in PC, and the prognostic potential of DNA methylation markers for PC has been demonstrated in multiple studies. The most promising methylation marker candidates identified so far include PITX2, C1orf114 (CCDC181) and the GABRE~miR-452~miR-224 locus, in addition to the three-gene signature AOX1/C1orf114/HAPLN3. Several other biomarker candidates have also been investigated, but with less stringent clinical validation and/or conflicting evidence regarding their possible prognostic value available at this time. Here, we review the current evidence for the prognostic potential of DNA methylation markers in PC. PMID:25238417

  13. 2-Methyl-6-(6-methyl-1H-benzimidazol-2-ylphenol–2-methyl-6-(5-methyl-1H-benzimidazol-2-ylphenol (3/1

    Suchada Chantrapromma

    2009-12-01

    Full Text Available The title compound, 0.75C15H14N2O·0.25C15H14N2O, is a co-crystal of 2-methyl-6-(6-methyl-1H-benzimidazol-2-ylphenol as the major component and 2-methyl-6-(5-methyl-1H-benzimidazol-2-ylphenol as the minor component. The refined site-occupancy ratio is 0.746 (4/0.254 (4. The conformations of both components are identical except for that of the methyl substituent on the benzene ring of the benzimidazole unit which is positionally disordered over two positions. The molecule is essentially planar, the dihedral angle between the benzimidazole plane and the benzene ring being 3.49 (4°. An intramolecular O—H...N hydrogen bond generates an S(6 ring motif. In the crystal packing, molecules are linked through N—H...O hydrogen bonds into chains along [201]. These chains are stacked approximately along the a-axis direction. The crystal packing is further stabilized by weak N—H...O and O...H...N hydrogen bonds, together with weak intermolecular C—H...π interactions. A π–π interaction with a centroid–centroid distance of 3.6241 (6 Å is also observed between the substituted phenyl ring and that of the benzimidazole system.

  14. Methyl Esters for Tumor Drug Delivery

    José Portilla-Arias

    2010-01-01

    Full Text Available New copolyesters derived from poly(β,L-malic acid have been designed to serve as nanoconjugate platforms in drug delivery. 25% and 50% methylated derivatives (coPMLA-Me25H75 and coPMLA-Me50H50 with absolute molecular weights of 32 600 Da and 33 100 Da, hydrodynamic diameters of 3.0 nm and 5.2 nm and zeta potential of −15 mV and −8.25 mV, respectively, were found to destabilize membranes of liposomes at pH 5.0 and pH 7.5 at concentrations above 0.05 mg/mL. The copolymers were soluble in PBS (half life of 40 hours and in human plasma (half life of 15 hours but they showed tendency to aggregate at high levels of methylation. Fluorescence-labeled copolymers were internalized into MDA-MB-231 breast cancer cells with increased efficiency for the higher methylated copolymer. Viability of cultured brain and breast cancer cell lines indicated moderate toxicity that increased with methylation. The conclusion of the present work is that partially methylated poly(β,L-malic acid copolyesters are suitable as nanoconjugate platforms for drug delivery.

  15. Histone Lysine Methylation in Diabetic Nephropathy

    Guang-dong Sun

    2014-01-01

    Full Text Available Diabetic nephropathy (DN belongs to debilitating microvascular complications of diabetes and is the leading cause of end-stage renal diseases worldwide. Furthermore, outcomes from the DCCT/EDIC study showed that DN often persists and progresses despite intensive glucose control in many diabetes patients, possibly as a result of prior episode of hyperglycemia, which is called “metabolic memory.” The underlying mechanisms responsible for the development and progression of DN remain poorly understood. Activation of multiple signaling pathways and key transcription factors can lead to aberrant expression of DN-related pathologic genes in target renal cells. Increasing evidence suggests that epigenetic mechanisms in chromatin such as DNA methylation, histone acetylation, and methylation can influence the pathophysiology of DN and metabolic memory. Exciting researches from cell culture and experimental animals have shown that key histone methylation patterns and the related histone methyltransferases and histone demethylases can play important roles in the regulation of inflammatory and profibrotic genes in renal cells under diabetic conditions. Because histone methylation is dynamic and potentially reversible, it can provide a window of opportunity for the development of much-needed novel therapeutic potential for DN in the future. In this minireview, we discuss recent advances in the field of histone methylation and its roles in the pathogenesis and progression of DN.

  16. Developmental differences in posttranslational calmodulin methylation in pea plants

    A calmodulin-N-methyltransferase was used to analyze the degree of lysine-115 methylation of pea calmodulin. Calmodulin was isolated from segments of developing roots of young etiolated and green pea plants and was tested for its ability to be methylated by the calmodulin methyltransferase in the presence of 3H-methyl-S-adenosylmethionine. Calmodulin methylation levels were lower in apical root segments and in the young lateral roots compared with the mature, differentiated root tissues. The methylation of these calmodulin samples occurs specifically at lysine 115 since site-directed mutants of calmodulin with substitutions at this position were not methylated and competitively inhibited methylation. The present findings, combined with previous data showing differences in NAD kinase activation by methylated and unmethylated calmodulins, raise the possibility that posttranslational methylation could affect calmodulin action

  17. MicroRNA Methylation in Colorectal Cancer.

    Kaur, Sippy; Lotsari-Salomaa, Johanna E; Seppänen-Kaijansinkko, Riitta; Peltomäki, Päivi

    2016-01-01

    Epigenetic alterations such as DNA methylation, histone modifications and non-coding RNA (including microRNA) associated gene silencing have been identified as a major characteristic in human cancers. These alterations may occur more frequently than genetic mutations and play a key role in silencing tumor suppressor genes or activating oncogenes, thereby affecting multiple cellular processes. In recent years, studies have shown that microRNAs, that act as posttranscriptional regulators of gene expression are frequently deregulated in colorectal cancer (CRC), via aberrant DNA methylation. Over the past decade, technological advances have revolutionized the field of epigenetics and have led to the identification of numerous epigenetically dysregulated miRNAs in CRC, which are regulated by CpG island hypermethylation and DNA hypomethylation. In addition, aberrant DNA methylation of miRNA genes holds a great promise in several clinical applications such as biomarkers for early screening, prognosis, and therapeutic applications in CRC. PMID:27573897

  18. Martian Methyl Chloride. A lesson in uncertainty

    Bains, William

    2013-01-01

    The MSL Lander Curiosity has recently detected methyl halides coming from heated samples of Martian soil. This is reminiscent of similar findings in the Viking Lander spacecraft. In the 1970s a consensus developed quickly explaining the methyl halides as contamination originating from the spacecraft, and ignoring lines of evidence that the two compounds originated from Mars, and that they could not have originated from the proposed spacecraft chemistry. I discuss why this consensus developed from the understanding of biochemistry and geochemistry of 1976, despite its implausibility. Subsequent explanations for the Viking methyl halides are more plausible but still not proven. The Curiosity rover results are also being explained as a result of on-spacecraft chemistry. I urge caution in this interpretation, in light of the historical Viking example: it is better to leave unexplained data unexplained than to lock in an explanation that precludes future developments.

  19. 氨基甲酸酯的抗磨性能及其作用机理的研究%Mechanism and performance of anti-wear properties of diamyl carbamate

    胡洁; 于宁; 杨翰林; 刘蕊; 陈化飞; 许玲玲; 宋应金

    2014-01-01

    采用四球试验机评价二戊基氨基甲酸酯单组分化合物在成品油中的抗磨性能,并通过X射线光电子能谱( XPS)分析了边界润滑膜的形成机理及作用机理。结果表明,二戊基氨基甲酸酯与ZD-DP及硼酸酯具有优良的复合效应,且在溶剂精制基础油中具有良好的感受性。%The anti-wear properties of diamyl carbamate in refine d oil product were evaluated by four-ball machine .The formation mechanism and action mechanism of boundary film were analysized by X-ray photoelectronic spectroscopy ( XPS) .The results showed that the dia-myl carbamate , ZDDP and borate ester had excellent composite effect .Moreover , they had good sensitivity in solvent refined base oil .

  20. Information Thermodynamics of Cytosine DNA Methylation.

    Sanchez, Robersy; Mackenzie, Sally A

    2016-01-01

    Cytosine DNA methylation (CDM) is a stable epigenetic modification to the genome and a widespread regulatory process in living organisms that involves multicomponent molecular machines. Genome-wide cytosine methylation patterning participates in the epigenetic reprogramming of a cell, suggesting that the biological information contained within methylation positions may be amenable to decoding. Adaptation to a new cellular or organismal environment also implies the potential for genome-wide redistribution of CDM changes that will ensure the stability of DNA molecules. This raises the question of whether or not we would be able to sort out the regulatory methylation signals from the CDM background ("noise") induced by thermal fluctuations. Here, we propose a novel statistical and information thermodynamic description of the CDM changes to address the last question. The physical basis of our statistical mechanical model was evaluated in two respects: 1) the adherence to Landauer's principle, according to which molecular machines must dissipate a minimum energy ε = kBT ln2 at each logic operation, where kB is the Boltzmann constant, and T is the absolute temperature and 2) whether or not the binary stretch of methylation marks on the DNA molecule comprise a language of sorts, properly constrained by thermodynamic principles. The study was performed for genome-wide methylation data from 152 ecotypes and 40 trans-generational variations of Arabidopsis thaliana and 93 human tissues. The DNA persistence length, a basic mechanical property altered by CDM, was estimated with values from 39 to 66.9 nm. Classical methylome analysis can be retrieved by applying information thermodynamic modelling, which is able to discriminate signal from noise. Our finding suggests that the CDM signal comprises a language scheme properly constrained by molecular thermodynamic principles, which is part of an epigenomic communication system that obeys the same thermodynamic rules as do current

  1. Promoter hypermethylation of methyl guanine methyl transferase in lung cancer patients of Kashmir valley

    Sheikh Mohd Shaffi

    2013-04-01

    Full Text Available Context: MGMT, is a DNA repair protein involved in removing the mutagenic and cytotoxic adducts from O 6 -guanine in DNA, which otherwise can lead to the mutation, primarily due to the tendency of O 6 -methylguanine to pair with thymine during replication, resulting in the conversion of GC to AT pairs, if left unrepaired due to epigenetic silencing of its promoter. Aims: To study the status of MGMT in Kashmiri lung cancer patients Materials and Methods: In this study we analyzed the promoter status of this gene in 50 lung cancer patients using methylation specific-PCR and confirmed by restriction digestion. Results: The promoter was found to be methylated in 52% of the cases, more in male patients (54.2% than in female patients (46.6%. When stratified according to smoking status, current smokers showed a strong association with methylation (OR = 6.0, P = 0.005 than former and never smokers. We also compared the promoter methylation of the MGMT gene with pesticide exposure, and found that patients with pesticide exposure had statistically significant (OR = 7.7 and P = 0.003 association with promoter methylation. Conclusions: Our results indicate that MGMT promoter methylation is associated with smoking exposure and there appears to be an association of MGMT promoter methylation with pesticide exposure in Kashmiri lung cancer patients.

  2. seqlm: an MDL based method for identifying differentially methylated regions in high density methylation array data

    Kolde, Raivo; Märtens, Kaspar; Lokk, Kaie; Laur, Sven; Vilo, Jaak

    2016-01-01

    Motivation: One of the main goals of large scale methylation studies is to detect differentially methylated loci. One way is to approach this problem sitewise, i.e. to find differentially methylated positions (DMPs). However, it has been shown that methylation is regulated in longer genomic regions. So it is more desirable to identify differentially methylated regions (DMRs) instead of DMPs. The new high coverage arrays, like Illuminas 450k platform, make it possible at a reasonable cost. Few tools exist for DMR identification from this type of data, but there is no standard approach. Results: We propose a novel method for DMR identification that detects the region boundaries according to the minimum description length (MDL) principle, essentially solving the problem of model selection. The significance of the regions is established using linear mixed models. Using both simulated and large publicly available methylation datasets, we compare seqlm performance to alternative approaches. We demonstrate that it is both more sensitive and specific than competing methods. This is achieved with minimal parameter tuning and, surprisingly, quickest running time of all the tried methods. Finally, we show that the regional differential methylation patterns identified on sparse array data are confirmed by higher resolution sequencing approaches. Availability and Implementation: The methods have been implemented in R package seqlm that is available through Github: https://github.com/raivokolde/seqlm Contact: rkolde@gmail.com Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27187204

  3. Genome-wide analysis of DNA methylation in hepatoblastoma tissues

    Cui, Ximao; Liu, Baihui; Zheng, Shan; Dong, Kuiran; Dong, Rui

    2016-01-01

    DNA methylation has a crucial role in cancer biology. In the present study, a genome-wide analysis of DNA methylation in hepatoblastoma (HB) tissues was performed to verify differential methylation levels between HB and normal tissues. As alpha-fetoprotein (AFP) has a critical role in HB, AFP methylation levels were also detected using pyrosequencing. Normal and HB liver tissue samples (frozen tissue) were obtained from patients with HB. Genome-wide analysis of DNA methylation in these tissues was performed using an Infinium HumanMethylation450 BeadChip, and the results were confirmed with reverse transcription-quantitative polymerase chain reaction. The Infinium HumanMethylation450 BeadChip demonstrated distinctively less methylation in HB tissues than in non-tumor tissues. In addition, methylation enrichment was observed in positions near the transcription start site of AFP, which exhibited lower methylation levels in HB tissues than in non-tumor liver tissues. Lastly, a significant negative correlation was observed between AFP messenger RNA expression and DNA methylation percentage, using linear Pearson's R correlation coefficients. The present results demonstrate differential methylation levels between HB and normal tissues, and imply that aberrant methylation of AFP in HB could reflect HB development. Expansion of these findings could provide useful insight into HB biology.

  4. DNA methylation and microRNAs in cancer

    Xiang-Quan Li; Yuan-Yuan Guo; Wei De

    2012-01-01

    DNA methylation is a type of epigenetic modification in the human genome,which means that gene expression is regulated without altering the DNA sequence.Methylation and the relationship between methylation and cancer have been the focus of molecular biology researches.Methylation represses gene expression and can influence embryogenesis and tumorigenesis.In different tissues and at different stages of life,the level of methylation of DNA varies,implying a fundamental but distinct role for methylation.When genes are repressed by abnormal methylation,the resulting effects can include instability of that gene and inactivation of a tumor suppressor gene.MicroRNAs have some aspects in common with this regulation of gene expression.Here we reviewed the influence of gene methylation on cancer and analyzed the methods used to profile methylation.We also assessed the correlation between methylation and other epigenetic modifications and microRNAs.About 55 845 research papers have been published about methylation,and one-fifth of these are about the appearance of methylation in cancer.We conclude that methylation does play a role in some cancer types.

  5. Methylation plotter: a web tool for dynamic visualization of DNA methylation data

    Mallona, Izaskun; Díez-Villanueva, Anna; Peinado, Miguel A

    2014-01-01

    Methylation plotter is a Web tool that allows the visualization of methylation data in a user-friendly manner and with publication-ready quality. The user is asked to introduce a file containing the methylation status of a genomic region. This file can contain up to 100 samples and 100 CpGs. Optionally, the user can assign a group for each sample (i.e. whether a sample is a tumoral or normal tissue). After the data upload, the tool produces different graphical representations of the results f...

  6. Safening effect of bentazon on cloransulam-methyl and halosulfuron-methyl in dry bean

    Peter H. Sikkema; Christy Shropshire; Nader Soltani

    2012-01-01

    Bentazon, applied as a tankmix, has been shown to have the potential for reducing the injury from some POST herbicides. Field experiments were conducted in 2008 and 2009 at Exeter, ON and in 2009 at Ridgetown, ON to determine if the addition of bentazon reduces the injury from cloransulam-methyl or halosulfuron-methyl applied POST in black, cranberry, kidney and white beans. Bentazon added to cloransulam-methyl reduced the level of injury 0 to 6% at 17.5 g·ai·ha–1 and 0...

  7. Methylation of DNA of maize and wheat grains during fumigation with methyl bromide

    The possibility that methylation of DNA occurs during fumigation of foodstuffs with methyl bromide was investigated in two grains, maize and wheat, using 14C-labeled fumigant. 7-Methylguanine and 1-methyladenine were identified as major products along with lesser amounts of 3-methylcytosine and 3-methyladenine. 3-Methylguanine was probably also formed in minor amounts. Although less than 1% of the bound radioactivity was associated with the DNA isolated, the results indicated that 0.5-1% of the guanine residues in the DNA of these grains was methylated during treatment with 48 mg/L methylbromide for 72 h

  8. Sensitive bi-enzymatic biosensor based on polyphenoloxidases-gold nanoparticles-chitosan hybrid film-graphene doped carbon paste electrode for carbamates detection.

    Oliveira, Thiago M B F; Barroso, M Fátima; Morais, Simone; Araújo, Mariana; Freire, Cristina; de Lima-Neto, Pedro; Correia, Adriana N; Oliveira, Maria B P P; Delerue-Matos, Cristina

    2014-08-01

    A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electrodeposition of a hybrid film onto a graphene doped carbon paste electrode (GPE). Graphene and the gold nanoparticles (AuNPs) were morphologically characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, dynamic light scattering and laser Doppler velocimetry. The electrodeposited hybrid film was composed of laccase (LACC), tyrosinase (TYR) and AuNPs entrapped in a chitosan (CS) polymeric matrix. Experimental parameters, namely graphene redox state, AuNPs:CS ratio, enzymes concentration, pH and inhibition time were evaluated. LACC-TYR-AuNPs-CS/GPE exhibited an improved Michaelis-Menten kinetic constant (26.9±0.5M) when compared with LACC-AuNPs-CS/GPE (37.8±0.2M) and TYR-AuNPs-CS/GPE (52.3±0.4M). Using 4-aminophenol as substrate at pH5.5, the device presented wide linear ranges, low detection limits (1.68×10(-9)±1.18×10(-10)-2.15×10(-7)±3.41×10(-9)M), high accuracy, sensitivity (1.13×10(6)±8.11×10(4)-2.19×10(8)±2.51×10(7)%inhibitionM(-1)), repeatability (1.2-5.8% RSD), reproducibility (3.2-6.5% RSD) and stability (ca. twenty days) to determine carbaryl, formetanate hydrochloride, propoxur and ziram in citrus fruits based on their inhibitory capacity on the polyphenoloxidases activity. Recoveries at two fortified levels ranged from 93.8±0.3% (lemon) to 97.8±0.3% (orange). Glucose, citric acid and ascorbic acid do not interfere significantly in the electroanalysis. The proposed electroanalytical procedure can be a promising tool for food safety control. PMID:24642204

  9. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases.

    Aly Abd-Ella

    Full Text Available Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low

  10. Study on the Interaction between Humic Substances in Soil and Carbamate Pesticides Using Fluorescence Quenching Titration Method%荧光猝灭滴定法研究土壤腐殖质与氨基甲酸酯类农药相互作用

    施国兰; 郑博福; 白英臣; 吴丰昌; 吴代赦

    2012-01-01

    为研究氨基甲酸酯类农药在溶解有机质参与下的迁移转化过程,利用荧光猝灭滴定法研究了土壤HS(腐殖质)与氨基甲酸酯类农药的相互作用.结果表明,呋喃丹和西维因的荧光都能不同程度地被FA(富里酸)和HA(腐殖酸)猝灭,主要猝灭机理为静电结合猝灭.采用静态猝灭模型计算出氨基甲酸酯类农药与HS的K(结合常数),lg K由大到小为呋喃丹-HA(4.96)>西维因-HA(4.93)>呋喃丹-FA(4.72)>西维因-FA(4.68).HA与氨基甲酸酯类农药的lgK明显大于FA与氨基甲酸酯类农药,表明HS与氨基甲酸酯类农药间的作用力有疏水作用.进一步研究表明,氢键作用对HS与氨基甲酯类农药结合有一定的影响.%To reveal the mechanisms of transport and conversion of carbamate pesticides in the presence of dissolved organic matters, the fluorescence quenching titration method was applied to investigate the interactions between carbamate pesticides and humic substances in soil. The results showed that the intrinsic fluorescence of carbofuran and carbaryl was quenched by the fulvic and humic acids to varying degrees. Static quenching was the primary mechanism during this process. The binding constants (K) of carbamate pesticides and humic substances were estimated using the fluorescence static quenching model. The order of lg K were: those of carbofuran and humic acid (4. 96) > those of carbaryl and humic acid (4. 93) > those of carbofuran and fulvic acid (4. 72) > those of carbaryl and fulvic acid (4. 68). The values of lg K of carbamate pesticides and humic acids were clearly higher than those of carbamate pesticides and fulvic acids. This result indicated that the hydrophobic force is one of the main interactions between carbamate pesticides and humic substances, and further proved that hydrogen bonding could slightly affect the bonding of carbamate pesticides and humic substances.

  11. Kinetic Isotope Effects in the Reduction of Methyl Iodide

    Holm, Torkil

    1999-01-01

    a-Deuterium kinetic isotope effects (KIE's) have been determined for the reaction of methyl iodide with a series of reducing agents. Reagents which transfer hydride ion in an SN2 reaction show small inverse or small normal KIE's. Reagents which transfer an electron to methyl iodide to produce...... methyl radical show large normal KIE's up to 20 % per a-D. Large KIE's were found for the reaction of methyl iodide with sodium, for Pd-catalyzed reaction of methyl iodide with hydrogen, for ET at a platinum cathode, for ET from benzophenone ketyl or from sodium naphthalenide, for iron catalyzed ET from...... a Grignard reagent to methyl iodide, and for reduction of methyl iodide with tributyltin hydride or with gaseous hydrogen iodide. Very small KIE's were found for electron transfer to methyl iodide from magnesium in ether or from sodium in ammonia. The reason may be that these reactions are transport...

  12. Consequences of dietary methyl donor supplements: Is more always better?

    Shorter, Kimberly R; Felder, Michael R; Vrana, Paul B

    2015-07-01

    Epigenetic mechanisms are now recognized to play roles in disease etiology. Several diseases increasing in frequency are associated with altered DNA methylation. DNA methylation is accomplished through metabolism of methyl donors such as folate, vitamin B12, methionine, betaine (trimethylglycine), and choline. Increased intake of these compounds correlates with decreased neural tube defects, although this mechanism is not well understood. Consumption of these methyl donor pathway components has increased in recent years due to fortification of grains and high supplemental levels of these compounds (e.g. vitamins, energy drinks). Additionally, people with mutations in one of the enzymes that assists in the methyl donor pathway (5-MTHFR) are directed to consume higher amounts of methyl donors to compensate. Recent evidence suggests that high levels of methyl donor intake may also have detrimental effects. Individualized medicine may be necessary to determine the appropriate amounts of methyl donors to be consumed, particularly in women of child bearing age. PMID:25841986

  13. Methylation of inorganic arsenic by murine fetal tissue explants.

    Broka, Derrick; Ditzel, Eric; Quach, Stephanie; Camenisch, Todd D

    2016-07-01

    Although it is generally believed that the developing fetus is principally exposed to inorganic arsenic and the methylated metabolites from the maternal metabolism of arsenic, little is known about whether the developing embryo can autonomously metabolize arsenic. This study investigates inorganic arsenic methylation by murine embryonic organ cultures of the heart, lung, and liver. mRNA for AS3mt, the gene responsible for methylation of arsenic, was detected in all embryonic tissue types studied. In addition, methylated arsenic metabolites were generated by all three tissue types. The fetal liver explants yielded the most methylated arsenic metabolites (∼7% of total arsenic/48 h incubation) while the heart, and lung preparations produced slightly greater than 2% methylated metabolites. With all tissues the methylation proceeded mostly to the dimethylated arsenic species. This has profound implications for understanding arsenic-induced fetal toxicity, particularly if the methylated metabolites are produced autonomously by embryonic tissues. PMID:26446802

  14. Enzymatic Synthesis of Methyl-Galactoaldehyde

    WANG Qun; YU Guangli

    2002-01-01

    Methyl-galactosides were oxidized at room temperature by galactose oxidase in a one-step reaction and affordedmethyl-galactoaldehyde in excellent yield and high purity. The resulting galactoaldehyde as a useful intermediate can be di-rectly used in glycopeptide synthesis.

  15. 27 CFR 21.116 - Methyl alcohol.

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Methyl alcohol. 21.116 Section 21.116 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants §...

  16. Methyl 3,4-bis(cyclopropylmethoxybenzoate

    Xian-Chao Cheng

    2011-05-01

    Full Text Available The title compound, C16H20O4, was obtained unintentionally as the byproduct of an attempted synthesis of methyl 3-(cyclopropylmethoxy-4-hydroxybenzoate. In the crystal, the molecules are linked by intermolecular C—H...O interactions.

  17. Atmospheric fate of methyl vinyl ketone

    Praske, Eric; Crounse, John D; Bates, Kelvin H; Kurtén, Theo; Kjærgaard, Henrik Grum; Wennberg, Paul O

    2015-01-01

    First generation product yields from the OH-initiated oxidation of methyl vinyl ketone (3-buten-2-one, MVK) under both low and high NO conditions are reported. In the low NO chemistry, three distinct reaction channels are identified leading to the formation of (1) OH, glycolaldehyde, and acetyl...

  18. DNA methylation markers for breast cancer prognosis

    Dedeurwaerder, Sarah; Fuks, François

    2012-01-01

    Currently, most of the prognostic and predictive gene expression signatures emerging for breast cancer concern the tumor component. In Dedeurwaerder et al. we show that DNA methylation profiling of breast tumors is a particularly sensitive means of capturing features of the immune component of breast tumors. Most importantly, correlation is observed between T-cell marker genes and breast cancer clinical outcome.

  19. Affinity-based enrichment strategies to assay methyl-CpG binding activity and DNA methylation in early Xenopus embryos

    Bogdanović Ozren

    2011-08-01

    Full Text Available Abstract Background DNA methylation is a widespread epigenetic modification in vertebrate genomes. Genomic sites of DNA methylation can be bound by methyl-CpG-binding domain proteins (MBDs and specific zinc finger proteins, which can recruit co-repressor complexes to silence transcription on targeted loci. The binding to methylated DNA may be regulated by post-translational MBD modifications. Findings A methylated DNA affinity precipitation method was implemented to assay binding of proteins to methylated DNA. Endogenous MeCP2 and MBD3 were precipitated from Xenopus oocyte extracts and conditions for methylation-specific binding were optimized. For a reverse experiment, DNA methylation in early Xenopus embryos was assessed by MBD affinity capture. Conclusions A methylated DNA affinity resin can be applied to probe for MBD activity in extracts. This assay has a broad application potential as it can be coupled to downstream procedures such as western blotting, fluorimetric HDAC assays and quantitative mass spectrometry. Methylated DNA affinity capture by methyl-CpG binding proteins produces fractions highly enriched for methylated DNA, suitable for coupling to next generation sequencing technologies. The two enrichment strategies allow probing of methyl-CpG protein interactions in early vertebrate oocytes and embryos.

  20. Quantitative DNA Methylation Analysis of Candidate Genes in Cervical Cancer

    Erin M Siegel; Riggs, Bridget M; Delmas, Amber L.; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D.

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and ...

  1. DNA methylation dynamics in muscle development and disease

    Monica Suelves

    2015-01-01

    DNA methylation is an essential epigenetic modification for mammalian development and is crucial for the establishment and maintenance of cellular identity. Traditionally, DNA methylation has been considered as a permanent repressive epigenetic mark. However, the application of genome-wide approaches has allowed the analysis of DNA methylation in different genomic contexts revealing a more dynamic regulation than originally thought, since active DNA methylation and demethylation occur during...

  2. DNA methylation dynamics in muscle development and disease

    Carrió, Elvira; Suelves, Mònica

    2015-01-01

    DNA methylation is an essential epigenetic modification for mammalian development and is crucial for the establishment and maintenance of cellular identity. Traditionally, DNA methylation has been considered as a permanent repressive epigenetic mark. However, the application of genome-wide approaches has allowed the analysis of DNA methylation in different genomic contexts revealing a more dynamic regulation than originally thought, since active DNA methylation and demethylation occur during ...

  3. Allele-Specific DNA Methylation Detection by Pyrosequencing®

    Sommer Kristensen, Lasse; Johansen, Jens Vilstrup; Grønbæk, Kirsten

    2015-01-01

    DNA methylation is an epigenetic modification that plays important roles in healthy as well as diseased cells, by influencing the transcription of genes. In spite the fact that human somatic cells are diploid, most of the currently available methods for the study of DNA methylation do not provide......-effective protocol for allele-specific DNA methylation detection based on Pyrosequencing(®) of methylation-specific PCR (MSP) products including a single nucleotide polymorphism (SNP) within the amplicon....

  4. Detection of MGMT promoter methylation in glioblastoma using pyrosequencing

    Xie, Hao; Tubbs, Raymond; Yang, Bin

    2015-01-01

    Recent clinical trials on patients with glioblastoma revealed that O6-Methylguanine-DNA methyltransferase (MGMT) methylation status significantly predicts patient’s response to alkylating agents. In this study, we sought to develop and validate a quantitative MGMT methylation assay using pyrosequencing on glioblastoma. We quantified promoter methylation of MGMT using pyrosequencing on paraffin-embedded fine needle aspiration biopsy tissues from 43 glioblastoma. Using a 10% cutoff, MGMT methyl...

  5. DNA Methylation as a Biomarker for Preeclampsia

    Anderson, Cindy M.; Ralph, Jody L.; Wright, Michelle L.; Linggi, Bryan E.; Ohm, Joyce E.

    2014-10-01

    Background: Preeclampsia contributes significantly to pregnancy-associated morbidity and mortality as well as future risk of cardiovascular disease in mother and offspring, and preeclampsia in offspring. The lack of reliable methods for early detection limits the opportunities for prevention, diagnosis, and timely treatment. Purpose: The purpose of this study was to explore distinct DNA methylation patterns associated with preeclampsia in both maternal cells and fetal-derived tissue that represent potential biomarkers to predict future preeclampsia and inheritance in children. Method: A convenience sample of nulliparous women (N = 55) in the first trimester of pregnancy was recruited for this prospective study. Genome-wide DNA methylation was quantified in first-trimester maternal peripheral white blood cells and placental chorionic tissue from normotensive women and those with preeclampsia (n = 6/group). Results: Late-onset preeclampsia developed in 12.7% of women. Significant differences in DNA methylation were identified in 207 individual linked cytosine and guanine (CpG) sites in maternal white blood cells collected in the first trimester (132 sites with gain and 75 sites with loss of methylation), which were common to approximately 75% of the differentially methylated CpG sites identified in chorionic tissue of fetal origin. Conclusion: This study is the first to identify maternal epigenetic targets and common targets in fetal-derived tissue that represent putative biomarkers for early detection and heritable risk of preeclampsia. Findings may pave the way for diagnosis of preeclampsia prior to its clinical presentation and acute damaging effects, and the potential for prevention of the detrimental long-term sequelae.

  6. Effects of Soil Residues of Sulfosulfuron and Mesosulfuron Methyl + Iodosulfuron Methyl Sodium on Sunflower Varieties

    Serim, Ahmet Tansel; MADEN, Salih

    2014-01-01

    Using field assays, we studied how the residues of sulfosulfuron and mesosulfuron methyl + iodosulfuron methyl sodium (ME+IMS) applied at two spraying times and three application rates affected two sunflower varieties seeded 12 months after treatment (MAT) in Central Anatolian Region, Turkey. Specifically, we studied their effects on the shoot length, seed yield, and yield components, including plant length, head diameter (HD), and 1000-seed weight. Sunflower yield was found to be the most se...

  7. A novel method for detecting 7-methyl guanine reveals aberrant methylation levels in Huntington disease

    Thomas, Beena; Matson, Samantha; Chopra, Vanita; Sun, Liping; Sharma, Swati; Hersch, Steven; Rosas, H. Diana; Scherzer, Clemens; Ferrante, Robert; Matson, Wayne

    2013-01-01

    Guanine methylation is a ubiquitous process affecting DNA and various RNA species. N-7 guanine methylation (7-MG), though relatively less studied, could have a significant role in normal transcriptional regulation as well as in the onset and development of pathological conditions. The lack of a sensitive method to accurately quantify trace amounts of altered bases like 7-MG, has been a major deterrent in delineating its biological function(s). Here we report the development of methods to dete...

  8. GSH2 promoter methylation in pancreatic cancer analyzed by quantitative methylation-specific polymerase chain reaction

    Gao, Fei; HUANG, HAO-JIE; Gao, Jun; Li, Zhao-Shen; Shu-ren MA

    2015-01-01

    Tumor suppressor gene silencing via promoter hypermethylation is an important event in pancreatic cancer pathogenesis. Aberrant DNA hypermethylation events are highly tumor specific, and may provide a diagnostic tool for pancreatic cancer patients. The objective of the current study was to identify novel methylation-related genes that may potentially be used to establish novel therapeutic and diagnostic strategies against pancreatic cancer. The methylation status of the GS homeobox 2 (GSH2) g...

  9. Simultaneous Determination of Salicylic Acid, Jasmonic Acid, Methyl Salicylate, and Methyl Jasmonate from Ulmus pumila Leaves by GC-MS

    Zhi-hong Huang

    2015-01-01

    Full Text Available Salicylic acid, jasmonic acid, methyl salicylate, and methyl jasmonate are important phytohormones and defensive signaling compounds, so it is of great importance to determine their levels rapidly and accurately. The study uses Ulmus pumila leaves infected by Tetraneura akinire Sasaki at different stages as materials; after extraction with 80% methanol and ethyl acetate and purification with primary secondary amine (PSA and graphitized carbon blacks (GCB, the contents of signal compounds salicylic acid, jasmonic acid, methyl salicylate, and methyl jasmonate were determined by GC-MS. The results showed that the level of salicylic acid, jasmonic acid, methyl salicylate, and methyl jasmonate increased remarkably in U. pumila once infected by T. akinire Sasaki, but the maximums of these four compounds occurred at different times. Salicylic acid level reached the highest at the early stage, and jasmonic acid level went to the maximum in the middle stage; by contrast, change of content of methyl salicylate and methyl jasmonate was the quite opposite.

  10. Synthesis of [methyl-14C]crotonobetaine from DL-[methyl-14C]carnitine

    The causes of carnitine deficiency syndromes are not completely understood, but decomposition of L-carnitine in vivo is likely to be involved. Carnitine is metabolized to γ-butyrobetaine, and crotonobetaine is probably an intermediate in this pathway. To validate experimentally the precursor-product relationship between the three physiologically occuring γ-betaines - L-carnitine, crotonobetaine, γ-butyrobetaine - labelling with stable or radioactive isotopes became necessary. Methyl-labelled carnitine isomers (L(-)-, D(+)- or DL-) or γ-butyrobetaine can be easily synthesized by methylation of 4-amino-3-hydroxybutyric acid isomers or 4-aminobutyric acid, respectively. Because of problems with the 4-aminocrotonic acid, we synthesized labelled crotonbetaine from labelled carnitine. Thus, DL-[methyl-14C]carnitine was dehydrated by reaction with concentrated sulfuric acid. After removal of the latter the products were separated and purified by ion exchange chromatography on DOWEX 50 WX8 (200 - 400 mesh) and gradient elution with hydrochloric acid. In addition to the labelled main product [methyl-14C]crotonobetaine (yield about 50 %), [methyl-14C]glycine betaine and [methyl-14C]acetonyl-trimethylammonium (ATMA) were formed. The end products were identified by combined thin layer chromatography/autoradiography and quantified by liquid scintillation counting. (Author)

  11. 2010年杭州市售发酵性食品中氨基甲酸乙酯调查与分析%Survey and analysis of ethyl carbamate in commercial fermented foods in Hangzhou in 2010

    吴平谷; 杨大进; 沈向红; 王立媛; 潘晓冬; 张晶; 赵永信; 谭莹

    2011-01-01

    Objective To observe the ethyl carbamate concentrations in different commercial fermented foods in Hangzhou in 2010.Methods In 2010,237 commercial fermented food samples of eight categories,including yellow wine,white spirit,wine,beer,cooking wine,sauce,vinegar and fermented bean curd,were purchased from 3 different size markets respectively in Hangzhou.The ethyl carbamate was measured by gas chromatography-mass spectrometry in selection ion mode,after the samples were coupled with D5-ethyl carbamate,and purified by diatomite solid phase extraction column.Results The results showed that ethyl carbamate was detected in all samples analyzed (100%) with the range from 2.0 μg/kg to 515.0 μg/kg.The ethyl carbamate average(median)levels in 8 food catergories were descending with fermented red bean curd (182.2 μg/kg (161.2 μg/kg)),yellow wine (159.6 μg/kg (121.0 μg/kg)),cooking wine (86.8 μg/kg (95.6 μg/kg)),white spirit (72.0 μg/kg (60.5 μg/kg)),soy sauce (47.2 μg/kg(40.7μg/kg)),vinegar (26.7 μg/kg (31.8 μg/kg)),wine (15.7 μg/kg (16.8 μg/kg)) and beer (2.2 μg/kg (2.3 μg/kg)).Conclusion The ethyl carbamate was detected in all fermented foods in Hangzhou in 2010,and the levels of ethyl carbamate in red bean curd and yellow wine were higher than others.%目的 调查2010年杭州市售发酵性食品中氨基甲酸乙酯含量.方法 2010年在杭州大、中、小型3家超市采集237份发酵性食品,包括黄酒、白酒、葡萄酒、啤酒、料酒、酱油、食醋、腐乳等8类食品,采用D5-氨基甲酸乙酯核素稀释技术,硅藻土固相萃取净化样品,然后用气相色谱-质谱法测定样品中氨基甲酸乙酯.结果 237份发酵性食品中氨基甲酸乙酯检出率为100%,含量范围为2.0 ~515.0 μg/kg,氨基甲酸乙酯含量平均值(中位数)从高到低依次为红腐乳[182.2 μg/kg(161.2 μg/kg )]、黄酒[159.6 μg/kg(121.0 μg/kg)]、料酒[86.8 μg/kg(95.6 μg/kg)]、白酒[72.0 μg/kg(60.5 μg/kg )]、酱油[47

  12. Evaluation of Methyl-Binding Domain Based Enrichment Approaches Revisited.

    Karolina A Aberg

    Full Text Available Methyl-binding domain (MBD enrichment followed by deep sequencing (MBD-seq, is a robust and cost efficient approach for methylome-wide association studies (MWAS. MBD-seq has been demonstrated to be capable of identifying differentially methylated regions, detecting previously reported robust associations and producing findings that replicate with other technologies such as targeted pyrosequencing of bisulfite converted DNA. There are several kits commercially available that can be used for MBD enrichment. Our previous work has involved MethylMiner (Life Technologies, Foster City, CA, USA that we chose after careful investigation of its properties. However, in a recent evaluation of five commercially available MBD-enrichment kits the performance of the MethylMiner was deemed poor. Given our positive experience with MethylMiner, we were surprised by this report. In an attempt to reproduce these findings we here have performed a direct comparison of MethylMiner with MethylCap (Diagenode Inc, Denville, NJ, USA, the best performing kit in that study. We find that both MethylMiner and MethylCap are two well performing MBD-enrichment kits. However, MethylMiner shows somewhat better enrichment efficiency and lower levels of background "noise". In addition, for the purpose of MWAS where we want to investigate the majority of CpGs, we find MethylMiner to be superior as it allows tailoring the enrichment to the regions where most CpGs are located. Using targeted bisulfite sequencing we confirmed that sites where methylation was detected by either MethylMiner or by MethylCap indeed were methylated.

  13. Analysis of DNA Cytosine Methylation on Cotton under Salt Stress

    ZHAO Yun-le; YE Wu-wei; WANG Jun-juan; FAN Bao-xiang

    2008-01-01

    @@ DNA methylation,especially methylation of cytosine in eukaryotic organisms,has been implicated in gene regulation,genomic imprinting,the timing of DNA replication,and determination of chromatin structure.It was reported that 6.5% of the whole cytosine residues in the nuclear DNA in higher plants were methylated.The methylation of cytosine in plant nuclear DNA occurs usually in both CpG and CpNG sequences,and the methylation state can be maintained through the cycles of DNA replication and is likely to play an integral role in regulating gene expression.

  14. DNA methylation: a new twist in the tail

    Gavin Kelsey

    2011-01-01

    DNA methylation is the epigenetic mark with the longest history and that we probably understand best, yet we still have no adequate account for why specific DNA sequences are selected to become methylated.Gene-specific DNA methylation is fundamental to processes such as developmental silencing of genes, classical epigenetic phenomena such as genomic imprinting, and occurs pathologically in the silencing of tumor suppressor genes in cancer.Fully understanding the mechanisms of methylation is thus of huge importance.In mammals,the acquisition of DNA methylation is determined by one of two de novo DNA methyltransferase enzymes, Dnmt3a and Dnmt3b.

  15. The DNA methylation events in normal and cloned rabbit embryos

    TaoChen; Yan-LingZhang; YanJiang; Shu-ZhenLiu; HeideSchatten; Da-YuanChen; Qing-YuanSun

    2005-01-01

    To study the DNA methylation events in normal and cloned rabbit embryos, we investigated the methylation status of a satellite seqnence and the promoter region of a single-copy gene using bisulfite-sequencing technology. During normal rabbit embryo development, both sequences maintained hypermethylation status until the 8- to 16-cell stage when progressive demethylation took place. In cloned embryos, the single-copy gene promoter sequence was rapidly demethylated and preco-ciously de novo methylated, while the satellite sequence mainrained the donor-type methylation status in all examined stages. Our results indicate that unique sequences as well as satellitesequences may have aberrant methylation patterns in cloned embryos.

  16. The global DNA methylation surrogate LINE-1 methylation is correlated with MGMT promoter methylation and is a better prognostic factor for glioma.

    Fumiharu Ohka

    Full Text Available Gliomas are the most frequently occurring primary brain tumor in the central nervous system of adults. Glioblastoma multiformes (GBMs, WHO grade 4 have a dismal prognosis despite the use of the alkylating agent, temozolomide (TMZ, and even low grade gliomas (LGGs, WHO grade 2 eventually transform to malignant secondary GBMs. Although GBM patients benefit from promoter hypermethylation of the O(6-methylguanine-DNA methyltransferase (MGMT that is the main determinant of resistance to TMZ, recent studies suggested that MGMT promoter methylation is of prognostic as well as predictive significance for the efficacy of TMZ. Glioma-CpG island methylator phenotype (G-CIMP in the global genome was shown to be a significant predictor of improved survival in patients with GBM. Collectively, we hypothesized that MGMT promoter methylation might reflect global DNA methylation. Additionally in LGGs, the significance of MGMT promoter methylation is still undetermined. In the current study, we aimed to determine the correlation between clinical, genetic, and epigenetic profiles including LINE-1 and different cancer-related genes and the clinical outcome in newly diagnosed 57 LGG and 54 GBM patients. Here, we demonstrated that (1 IDH1/2 mutation is closely correlated with MGMT promoter methylation and 1p/19q codeletion in LGGs, (2 LINE-1 methylation levels in primary and secondary GBMs are lower than those in LGGs and normal brain tissues, (3 LINE-1 methylation is proportional to MGMT promoter methylation in gliomas, and (4 higher LINE-1 methylation is a favorable prognostic factor in primary GBMs, even compared to MGMT promoter methylation. As a global DNA methylation marker, LINE-1 may be a promising marker in gliomas.

  17. Regulation and function of DNA methylation in plants and animals

    He, Xinjian

    2011-02-15

    DNA methylation is an important epigenetic mark involved in diverse biological processes. In plants, DNA methylation can be established through the RNA-directed DNA methylation pathway, an RNA interference pathway for transcriptional gene silencing (TGS), which requires 24-nt small interfering RNAs. In mammals, de novo DNA methylation occurs primarily at two developmental stages: during early embryogenesis and during gametogenesis. While it is not clear whether establishment of DNA methylation patterns in mammals involves RNA interference in general, de novo DNA methylation and suppression of transposons in germ cells require 24-32-nt piwi-interacting small RNAs. DNA methylation status is dynamically regulated by DNA methylation and demethylation reactions. In plants, active DNA demethylation relies on the repressor of silencing 1 family of bifunctional DNA glycosylases, which remove the 5-methylcytosine base and then cleave the DNA backbone at the abasic site, initiating a base excision repair (BER) pathway. In animals, multiple mechanisms of active DNA demethylation have been proposed, including a deaminase- and DNA glycosylase-initiated BER pathway. New information concerning the effects of various histone modifications on the establishment and maintenance of DNA methylation has broadened our understanding of the regulation of DNA methylation. The function of DNA methylation in plants and animals is also discussed in this review. © 2011 IBCB, SIBS, CAS All rights reserved.

  18. [Research advances in methyl bromide in the ocean].

    Du, Hui-na; Xie, Wen-xia; Cui, Yu-qian; Chen, Jian-lei; Ye, Si-yuan

    2014-12-01

    Methyl bromide is an important atmospheric trace gas, which plays significant roles in the global warming and atmospheric chemistry. The ocean plays important and complex roles in the global biogeochemical cycles of methyl bromide, not only the source of atmospheric methyl bromide, but also the sink. Therefore, developing the chemical research of the soluble methyl bromide in the ocean, will not only have a certain guiding significance to the atmospheric ozone layer protection, but also provide a theoretical basis for estimating methyl bromide's contribution to the global environmental change on global scale. This paper reviewed the research advances on methyl bromide in the ocean, from the aspects of the biogeochemical cycle of methyl bromide in the ocean, the analysis and determination method, the concentration distribution, the sea-to-air flux and its sources and sinks in the atmosphere. Some deficiencies in the current studies were put forward, and the directions of the future studies were prospected. PMID:25876424

  19. Structural Basis for Methyl Transfer by a Radical SAM Enzyme

    Boal, Amie K.; Grove, Tyler L.; McLaughlin, Monica I.; Yennawar, Neela H.; Booker, Squire J.; Rosenzweig, Amy C. (NWU); (Penn)

    2014-10-02

    The radical S-adenosyl-l-methionine (SAM) enzymes RlmN and Cfr methylate 23S ribosomal RNA, modifying the C2 or C8 position of adenosine 2503. The methyl groups are installed by a two-step sequence involving initial methylation of a conserved Cys residue (RlmN Cys{sup 355}) by SAM. Methyl transfer to the substrate requires reductive cleavage of a second equivalent of SAM. Crystal structures of RlmN and RlmN with SAM show that a single molecule of SAM coordinates the [4Fe-4S] cluster. Residue Cys{sup 355} is S-methylated and located proximal to the SAM methyl group, suggesting the SAM that is involved in the initial methyl transfer binds at the same site. Thus, RlmN accomplishes its complex reaction with structural economy, harnessing the two most important reactivities of SAM within a single site.

  20. One electron oxidation of 4-methyl thiophenol

    4-Methyl thiophenol(MTP) undergoes one electron oxidation with N3. and Br2-. radicals at pH 11 to give 4-methyl phenylthiyl radical (CH3C6H4S.) with λmax at 310 and 500 nm. OH radicals react with MTP by addition to the benzene ring and also by oxidation to give both hydroxycyclohexadienyl type radicals (∼ 25%, λmax = 390 nm) and CH3C6H4S. radicals (∼ 75%). In acidic solutions, H-atoms, CO2-. and (CH3)2COH radicals abstract H-atom from -SH group to give the same species, thus acting as oxidants. This radical was found to be neither oxidising nor reducing in nature and decayed by second order kinetics. (author). 2 refs., 2 figs

  1. Clean production of methyl ethyl ketone (MEK)

    Methyl ethyl ketone oxime (MEKO) was obtained by reaction of methyl ethyl ketone (MEK) with ammonia and hydrogen peroxide using titanium silicalite-1 (TS-1) as catalyst. The effect of reaction temperature, type of solvent, molar ratios of NH3/MEK, H2O2/MEK and mg catalyst/mmol MEK ratio was studied. Water was the most appropriate solvent to obtain high selectivity to oxime. 100% selectivity to MEKO and 60% conversion of MEK was obtained at 70 Celsius degrade using the following parameters: H2O2/MEK = 0,7 and NH3/MEK = 1,12. mg.catalyst/mmol MEK = 10,5. Little decrease in the catalytic activity was observed after reusing the catalysts twice suggesting that incorporated Ti in the MFI structure is rather stable under the studied conditions

  2. Methyl bromide residues in fumigated cocoa beans

    The 14C activity in unroasted [14C]-methyl bromide fumigated cocoa beans was used to study the fate and persistence of CH3Br in the stored beans. About 70% of the residues occurred in the shells. Unchanged CH3Br could not be detected, all the sorbed CH3Br having reacted with bean constituents apparently to form 14C-methylated derivatives and inorganic bromide. No 14C activity was found in the lipid fraction. Roasting decreased the bound (non-volatile) residues, with corresponding changes in the activities and amounts of free sugars, free and protein amino acids. Roasted nibs and shells showed a two-fold increase in the volatile fraction of the 14C residue. This fraction may be related to the volatile aroma compounds formed by Maillard-type reactions. (author)

  3. DNA Methylation Analysis: Choosing the Right Method

    Sergey Kurdyukov

    2016-01-01

    Full Text Available In the burgeoning field of epigenetics, there are several methods available to determine the methylation status of DNA samples. However, choosing the method that is best suited to answering a particular biological question still proves to be a difficult task. This review aims to provide biologists, particularly those new to the field of epigenetics, with a simple algorithm to help guide them in the selection of the most appropriate assay to meet their research needs. First of all, we have separated all methods into two categories: those that are used for: (1 the discovery of unknown epigenetic changes; and (2 the assessment of DNA methylation within particular regulatory regions/genes of interest. The techniques are then scrutinized and ranked according to their robustness, high throughput capabilities and cost. This review includes the majority of methods available to date, but with a particular focus on commercially available kits or other simple and straightforward solutions that have proven to be useful.

  4. DNA Methylation: Insights into Human Evolution.

    Irene Hernando-Herraez; Raquel Garcia-Perez; Sharp, Andrew J; Tomas Marques-Bonet

    2015-01-01

    A fundamental initiative for evolutionary biologists is to understand the molecular basis underlying phenotypic diversity. A long-standing hypothesis states that species-specific traits may be explained by differences in gene regulation rather than differences at the protein level. Over the past few years, evolutionary studies have shifted from mere sequence comparisons to integrative analyses in which gene regulation is key to understanding species evolution. DNA methylation is an important ...

  5. Methyl 5-(2-bromoacetyl-2-propoxybenzoate

    Jiang Ke

    2008-07-01

    Full Text Available The title compound, C13H15BrO4, was synthesized from methyl 5-acetyl-2-hydroxybenzoate. With the exception of the ester group and some H atoms, the molecule is planar, the average deviation from planarity being 0.086 (5 Å. The dihedral angle between the phenyl ring and the ester group is 41.6 (3°. Adjacent molecules are interconnected by C—H...O bonds, generating a layered structure.

  6. Arginine methylation regulates the p53 response

    Jansson, Martin; Durant, Stephen T; Cho, Er-Chieh;

    2008-01-01

    Activation of the p53 tumour suppressor protein in response to DNA damage leads to apoptosis or cell-cycle arrest. Enzymatic modifications are widely believed to affect and regulate p53 activity. We describe here a level of post-translational control that has an important functional consequence on...... of p53. Furthermore, PRMT5 depletion triggers p53-dependent apoptosis. Thus, methylation on arginine residues is an underlying mechanism of control during the p53 response....

  7. Kinetics of enzymatic hydrolysis of methyl ricinoleate

    Neeharika, T. S.V.R.; Lokesh, P.; Prasanna Rani, K. N.; Prathap Kumar, T.; Prasad, R. B.N.

    2015-01-01

    Ricinoleic acid is an unsaturated hydroxy fatty acid that naturally occurs in castor oil in proportions of up to 85–90%. Ricinoleic acid is a potential raw material and finds several applications in coatings, lubricant formulations and pharmaceutical areas. Enzymatic hydrolysis of castor oil is preferred over conventional hydrolysis for the preparation of ricinoleic acid to avoid estolide formation. A kinetics analysis of the enzymatic hydrolysis of Methyl Ricinoleate in the presence of Candi...

  8. CATECHOL-O-METHYL TRANSFERASE AND SCHIZOPHRENIA

    Šagud, Marina; Műck-Šeler, Dorotea; Mihaljević-Peleš, Alma; Vuksan-Ćusa, Bjanka; Živković, Maja; Jakovljević, Miro; Pivac, Nela

    2010-01-01

    Catechol-O-methyl transferase (COMT) is an enzyme involved in the degradation of dopamine. The most commonly examined polymorphism within the COMT gene is Val108/158Met polymorphism, which results in three to fourfold difference in COMT enzyme activity. It is particularely important in prefrontal cortex, since COMT activity is the most important regulator of the prefrontal dopamine function. Given the association between schizophrenia and decreased dopamine activity in the prefrontal corte...

  9. Liberation of methyl acrylate from metallalactone complexes via M-O ring opening (M = Ni, Pd) with methylation agents

    Lee, S. Y Tina

    2013-01-01

    Ring opening of various nickela- and palladalactones induced by the cleavage of the M-O bond by methyl trifluoromethanesulfonate (MeOTf) and methyl iodide (MeI) is examined. Experimental evidence supports the mechanism of ring opening by the alkylating agent followed by β-H elimination leading to methyl acrylate and a metal-hydride species. MeOTf shows by far higher efficiency in the lactone ring opening than any other methylating agent including the previously reported methyl iodide. © 2013 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

  10. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Erin M Siegel

    Full Text Available Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2. A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003. Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated.

  11. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Siegel, Erin M; Riggs, Bridget M; Delmas, Amber L; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2). A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site) per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC) of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003). Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated. PMID:25826459

  12. Dynamic instability of genomic methylation patterns in pluripotent stem cells

    Ooi Steen KT

    2010-09-01

    Full Text Available Abstract Background Genomic methylation patterns are established during gametogenesis, and perpetuated in somatic cells by faithful maintenance methylation. There have been previous indications that genomic methylation patterns may be less stable in embryonic stem (ES cells than in differentiated somatic cells, but it is not known whether different mechanisms of de novo and maintenance methylation operate in pluripotent stem cells compared with differentiating somatic cells. Results In this paper, we show that ablation of the DNA methyltransferase regulator DNMT3L (DNA methyltransferase 3-like in mouse ES cells renders them essentially incapable of de novo methylation of newly integrated retroviral DNA. We also show that ES cells lacking DNMT3L lose DNA methylation over time in culture, suggesting that DNA methylation in ES cells is the result of dynamic loss and gain of DNA methylation. We found that wild-type female ES cells lose DNA methylation at a much faster rate than do male ES cells; this defect could not be attributed to sex-specific differences in expression of DNMT3L or of any DNA methyltransferase. We also found that human ES and induced pluripotent stem cell lines showed marked but variable loss of methylation that could not be attributed to sex chromosome constitution or time in culture. Conclusions These data indicate that DNA methylation in pluripotent stem cells is much more dynamic and error-prone than is maintenance methylation in differentiated cells. DNA methylation requires DNMT3L in stem cells, but DNMT3L is not expressed in differentiating somatic cells. Error-prone maintenance methylation will introduce unpredictable phenotypic variation into clonal populations of pluripotent stem cells, and this variation is likely to be much more pronounced in cultured female cells. This epigenetic variability has obvious negative implications for the clinical applications of stem cells.

  13. Oxytocin receptor DNA methylation in postpartum depression.

    Kimmel, Mary; Clive, Makena; Gispen, Fiona; Guintivano, Jerry; Brown, Tori; Cox, Olivia; Beckmann, Matthias W; Kornhuber, Johannes; Fasching, Peter A; Osborne, Lauren M; Binder, Elisabeth; Payne, Jennifer L; Kaminsky, Zachary

    2016-07-01

    The oxytocin receptor (OXTR) is a key regulator of stress and anxiety and may be regulated by both psychosocial risk factors and gonadal hormones, making it an attractive candidate for study in postpartum depression (PPD). The objective of this study was to investigate both serum hormone and PPD specific DNA methylation variation in the OXTR. Illumina HM450 microarray data generated in a prospective PPD cohort identified significant associations (P=0.014) with PPD in an intronic region in the OXTR located 4bp proximal to an estrogen receptor (ER) binding region. Pyrosequencing confirmed moderate evidence for an interaction of CpGs in the region with childhood abuse status to mediate PPD. These CpGs located on chr3 at positions 8810078 and 8810069 exhibited significant associations with postpartum depression scores from an independent cohort of 240 women with no prior psychiatric history. Hormone analysis suggested a PPD specific negative correlation of DNA methylation in the region with serum estradiol levels. Estradiol levels and OXTR DNA methylation exhibited a significant interaction to associate with the ratio of allopregnanolone to progesterone. Cumulatively, the data corroborate our previous hypotheses of a PPD specific increased sensitivity of epigenetic reprogramming at estrogen target genes and suggests that OXTR epigenetic variation may be an important mediator of mood relevant neuroactive steroid production. PMID:27108164

  14. Neural Tube Defects, Folic Acid and Methylation

    Henk J. Blom

    2013-09-01

    Full Text Available Neural tube defects (NTDs are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s underlying human folic acid responsiveness in NTDs. However, several lines of evidence suggest that not only folates but also choline, B12 and methylation metabolisms are involved in NTDs. Decreased B12 vitamin and increased total choline or homocysteine in maternal blood have been shown to be associated with increased NTDs risk. Several polymorphisms of genes involved in these pathways have also been implicated in risk of development of NTDs. This raises the question whether supplementation with B12 vitamin, betaine or other methylation donors in addition to folic acid periconceptional supplementation will further reduce NTD risk. The objective of this article is to review the role of methylation metabolism in the onset of neural tube defects.

  15. Modified TEDA impregnants for methyl iodine removal

    One of the more successful impregnants for methyl iodide removal has been TEDA (Triethylene Diamine). The high activity of this compound owes as much to its rigid structure as to its basicity. Drawbacks to the use of TEDA as an impregnant have been (1) its vapor pressure and (2) that it is a solid and must be dissolved in water before applying to the charcoal. It is reported that the addition of C-Alkyl groups to the TEDA molecule can serve the purpose of decreasing the vapor pressure of the TEDA molecule. Thus improved performance at higher temperatures is expected when such modified TEDA compounds are used. Charcoals impregnated with C-Alkyl derivatives of TEDA are capable of retentions of more than 99% of the input methyl iodide under standard test conditions at 1300C, 95% R.H. Repeated tests of such charcoals have shown their ability, under standard test conditions, to retain greater than 99% methyl iodide at 250C, 95% R.H

  16. Differential methylation tests of regulatory regions.

    Ryu, Duchwan; Xu, Hongyan; George, Varghese; Su, Shaoyong; Wang, Xiaoling; Shi, Huidong; Podolsky, Robert H

    2016-06-01

    Differential methylation of regulatory elements is critical in epigenetic researches and can be statistically tested. We developed a new statistical test, the generalized integrated functional test (GIFT), that tests for regional differences in methylation based on the methylation percent at each CpG site within a genomic region. The GIFT uses estimated subject-specific profiles with smoothing methods, specifically wavelet smoothing, and calculates an ANOVA-like test to compare the average profile of groups. In this way, possibly correlated CpG sites within the regulatory region are compared all together. Simulations and analyses of data obtained from patients with chronic lymphocytic leukemia indicate that GIFT has good statistical properties and is able to identify promising genomic regions. Further, GIFT is likely to work with multiple different types of experiments since different smoothing methods can be used to estimate the profiles of data without noise. Matlab code for GIFT and sample data are available at http://www.augusta.edu/mcg/biostatepi/people/software/gift.html. PMID:26982617

  17. Structure and Vibrational Spectra of Tert-butyl N-(2- bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate%Tert-butyl(N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate的结构和振动光谱

    2007-01-01

    The molecular structure, conformational stability, and vibrational frequencies of tert-butyl N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate (TBBFC) were investigated by utilizing the Hartree-Fock (HF) and density functional theory (DFT) ab initio calculations with 6-31G* and 6-31G* * basis sets. The optimized bond length and angle values obtained by HF method showed the best agreement with the experimental values. Comparison of the observed and calculated fundamental vibrational frequencies indicated that B3LYP was superior to the scaled HF approach for molecular problems. Optimal uniform scaling factors calculated for the title compound are 0.899/0.904,0.958/0.961, and 0.988/0.989 for HF, B3LYP, and BLYP (6-31G */6-31G* *), respectively.

  18. (9H-Fluoren-9-ylmethyl N-{(2R,3R,4S-4-hydroxy-2-[(2S,5R-2-isopropyl-5-methylcyclohexyloxy]-5-oxooxolan-3-yl}carbamate propan-2-ol 0.334-solvate

    Graeme J. Gainsford

    2012-02-01

    Full Text Available The title compound, C29H35NO6.0.334C3H8O, a novel chiral N-(fluoren-9-ylmethyloxyxcarbonyl precursor, crystallizes with two independent carbamate (M molecules and propan-2-ol solvent molecules in the unit cell. Its crystal structure has been determined from barely adequate data obtained from a multi-fragment needle crystal. In the crystal, N—H...O hydrogen bonds link M molecules related by translation along the a axis into two independent chains. The ordered solvent molecule, having a partial occupancy of 0.334, is attached to one independent M molecule through O—H...O hydrogen bonds. The crystal packing exhibits weak intermolecular C—H...O interactions and voids of 270 Å3 filled with randomly disordered solvent molecules which were handled using the SQUEEZE methodology.

  19. 固相萃取-高效液相色谱法测定黄酒中氨基甲酸乙酯%Determination of Ethyl Carbamate in Yellow Rice Wine by Solid- phase Extraction Coupled with HPLC

    诸葛庆; 李博斌; 江涛; 寿谦; 葛乐勇; 曾红艳

    2012-01-01

    建立一种反相高效液相色谱法测定黄酒中氨基甲酸乙酯的方法。样品经固相萃取柱净化后衍生,采用反相C18色谱柱XB—Cfsf4.6mm×250mm,5μm),以乙腈-0.02moL/L乙酸纳水溶液为流动相进行梯度洗脱,流速为lmL/min;设定荧光检测器中激发波长为233nm,发射波长为600nm,对黄酒中的氨基甲酸乙酯进行检测。结果表明,在50.0-250.0μg/L添加量范围内,平均回收率为92.9%,相对标准偏差为4.5%(n=6)。方法的检出限为10μg/L,线性范围为100~1500μg/L(R=0.9995),测定结果与标准气相色谱一质谱法基本相同。所建立的方法可以作为黄酒中氨基甲酸乙酯的检测方法。%A reverse phase HPLC method for the determination of ethyl carbamate in yellow rice wine had been developed. Wine samples were firstly pretreated by solid-phase extraction,ethyl carbamate was separated on a XB- CL8 (4.6mm×250 mm,5 μm) by using gradient elution (acetonitrile and 0.02 moL/L sodium acetate as the mobile phase) at a flow rate of lmL/min and detected by a fluorescence detector (kex=233 nm, hem=600 nm). At the spike levels of 50.0,100.0 and 250.0μg/L, the average recovery for ethyl carbamate was 92.9% with RSD as 4.5 % (n = 6), the detection limit was 10 μg/L, and the linear range was from 100-500μg/L(R=0.9995.The determination results by this method were almost the same as those by GCMS. Therefore, this method could be use to determine ethyl carbamate in yellow rice wine.

  20. 高效液相色谱直接进样法测定水中氨基甲酸酯%Determination carbamates in ambient water by direct injection -HPLC -FD

    陈军; 卜伟; 程滢; 张宗祥

    2008-01-01

    采用直接进样-高效液相色谱-荧光检测,Waters Carbamate Analysis3.9×150 mm色谱柱,以水-甲醇-乙腈为流动相,激发波长为339nm,发射波长为445 nm定量测定水中的氨基甲酸酯.结果表明本方法的标准偏差在0.02-0.12 μg/L之间,变异系数在1.07%-7.24%之间,平均回收率在89.5%-100.5%之间,检出限在0.06-0.36 μg/L之间.

  1. Measurement of Ethyl Carbamate Content in Baijiu(Liquor) by SPE Coupled with GC-MS%SPE结合GC-MS法测定白酒中的氨基甲酸乙酯

    李安军; 刘国英; 汤有宏; 张严; 高江婧; 姜利; 张培龙

    2014-01-01

    氨基甲酸乙酯(Ethyl carbamate,EC)是发酵食品和酒精饮料制造过程伴随产生的一种具有潜在致癌性的物质.采取固相萃取结合GC-MS以氨基甲酸丙酯(PC)为内标的方法测定白酒中EC的含量,并完善优化实验条件.结果表明,该方法平均回收率为90.52%,相对标准偏差(RSD)为4.97%,检出限2.8 μg/L.适用于白酒中EC的日常分析检测.

  2. Fatty Acid Amide Hydrolase (FAAH), Acetylcholinesterase (AChE), and Butyrylcholinesterase (BuChE): Networked Targets for the Development of Carbamates as Potential Anti-Alzheimer's Disease Agents.

    Montanari, Serena; Scalvini, Laura; Bartolini, Manuela; Belluti, Federica; Gobbi, Silvia; Andrisano, Vincenza; Ligresti, Alessia; Di Marzo, Vincenzo; Rivara, Silvia; Mor, Marco; Bisi, Alessandra; Rampa, Angela

    2016-07-14

    The modulation of the endocannabinoid system is emerging as a viable avenue for the treatment of neurodegeneration, being involved in neuroprotective and anti-inflammatory processes. In particular, indirectly enhancing endocannabinoid signaling to therapeutic levels through FAAH inhibition might be beneficial for neurodegenerative disorders such as Alzheimer's disease, effectively preventing or slowing the progression of the disease. Hence, in the search for a more effective treatment for Alzheimer's disease, in this paper, the multitarget-directed ligand paradigm was applied to the design of carbamates able to simultaneously target the recently proposed endocannabinoid system and the classic cholinesterase system, and achieve effective dual FAAH/cholinesterase inhibitors. Among the two series of synthesized compounds, while some derivatives proved to be extremely potent on a single target, compounds 9 and 19 were identified as effective dual FAAH/ChE inhibitors, with well-balanced nanomolar activities. Thus, 9 and 19 might be considered as new promising candidates for Alzheimer's disease treatment. PMID:27309570

  3. 高效液相色谱直接进样法测定水中氨基甲酸酯%To Directly Detect Carbamate in Ambient Water by HPLC

    程滢; 陈军; 薛锐

    2007-01-01

    采用高效液相色谱法测定水中氨基甲酸酯,用Waters Carbamate Analysis3.9×150mm色谱柱,以水-甲醇-乙腈为流动相,用激发波长为339nm,发射波长为445nm的荧光检测器定量测定水中氨基甲酸酯的含量,结果表明本方法的标准偏差在0.02~0.12μg/L之间,变异系数在1.07%~7.24%之间,平均回收率在89.5%~100.5%之间.

  4. Novel 1,3-diacylamidopropane-2-[bis-(2-dimethylaminoethane)] carbamate pH-sensitive lipids for cationic liposome-mediated transfection

    Spelios, Michael G.

    A novel series of 1,3-diacylamidopropane-2-[bis(2-dimethylaminoethane)] carbamate analogs (1,3lb) were designed for cationic lipid-assisted transfection (lipofection). First, their physicochemical properties in self-assemblies with and without plasmid DNA (pDNA) were evaluated to examine the effects of hydrophobic tail length and degree of saturation on gene delivery and expression. Significant in vitro lipofection was induced at a nitrogen:phosphate ratio (N:P) of 4:1 by the dimyristoyl, dipalmitoyl, and dioleoyl analogs 1,3lb2, 1,3lb3, and 1,3lb5, respectively, without inclusion of neutral "lipofection enhancing" co-lipids in the cationic lipid formulations. Lipofection was reduced in the presence of co-lipids except for 1,3lb5 which maintained reporter gene expression levels at N:P 4:1 and yielded increased bioactivity at a lower NP of 2:1. Physicochemical characterization of the bioactive transfection agents (cytofectins) revealed: high hydration and in-plane elasticity of lipid monolayers by Langmuir film balance measurements; fluid lipid bilayers, with gel---liquid crystalline phase transitions below physiological temperature, by fluorescence anisotropy; lipid mixing with biomembrane-mimicking vesicles by fluorescence resonance energy transfer; efficient pDNA binding and compaction by ethidium bromide displacement; cationic liposome---nucleic acid complexes (lipoplexes) with large particle sizes (mean diameter ≥ 500 nm) and zeta potentials of positive values by dynamic light scattering and electrophoretic mobility, respectively. The results suggest that well hydrated and elastic cationic lipids forming fluid lamellar assemblies are extremely potent and minimally toxic cytofectins. Second, a comparison was made between 1,3lb2 and two derivatives, one an isomer with a shorter space between the myristoyl chains and the other the monovalent form, in an effort to delineate the biological effects of interchain distance and pH-induced polar headgroup expandability

  5. Methyl chloride and methyl bromide emissions from baking: an unrecognized anthropogenic source.

    Thornton, Brett F; Horst, Axel; Carrizo, Daniel; Holmstrand, Henry

    2016-05-01

    Methyl chloride and methyl bromide (CH3Cl and CH3Br) are the largest natural sources of chlorine and bromine, respectively, to the stratosphere, where they contribute to ozone depletion. We report the anthropogenic production of CH3Cl and CH3Br during breadbaking, and suggest this production is an abiotic process involving the methyl ester functional groups in pectin and lignin structural polymers of plant cells. Wide variations in baking styles allow only rough estimates of this flux of methyl halides on a global basis. A simple model suggests that CH3Br emissions from breadbaking likely peaked circa 1990 at approximately 200tonnes per year (about 0.3% of industrial production), prior to restrictions on the dough conditioner potassium bromate. In contrast, CH3Cl emissions from breadbaking may be of similar magnitude as acknowledged present-day CH3Cl industrial emissions. Because the mechanisms involve functional groups and compounds widely found in plant materials, this type of methyl halide production may occur in other cooking techniques as well. PMID:26878644

  6. 2010年杭州市蔬菜有机磷和氨基甲酸酯农药残留状况分析%Analysis of organophosphorus and carbamate pesticide residues in vegetables collected from Hangzhou in 2010

    何良兴; 张瓅文; 李燕

    2011-01-01

    目的:了解杭州市蔬菜农药残留情况,为蔬菜质量安全的监管和控制工作提供科学依据.方法:采集蔬菜样品446577批次,测定有机磷和氨基甲酸酯农药残留量,并对结果进行分析总结.结果:蔬菜年均农药超标率为0.09%,残留农药以有机磷为主,不同品种蔬菜的超标率与超标农药类型都不同,杭州本地与外地蔬菜农药超标率没有显著不同.结论:杭州市蔬菜农药残留水平较低,质量安全状况良好,但禁用农药还需要进一步加强监管.%Objective: To investigate the conditions of organophosphorus and carbamate pesticide residues in vegetables in Hangzhou in order to provide the basis for surveillance and control of vegetables safety. Methods: The total 446,577 samples of vegetables were collected and their residues of organophosphorus and carbamate were measured. At last, the results were analysised and summaried. Results: The disqualification rate of vegetables is 0.09%. The organophosphorus is the main pesticide residues. The disqualification rate and the type of pesticide residues varies in different kinds of vegetables. There's no difference in the disqualification rate of vegetables between Hangzhou and other places. Conclusion: The level of pesticide residues is low,and vegetable quality of Hangzhou is good, but supervision and administration on the forbidden pesticides should be strengthened.

  7. Rapid Determination of Organic Phosphorus and Carbamate Pesticides in Samples%样品中有机磷与氨基甲酸酯类农药快速检测方法的建立

    卫海燕; 邵华

    2011-01-01

    目的 建立现场快速筛选区分有机磷农药和氨基甲酸酯类农药的方法.方法 在薄层色谱原理基础上,利用毛细管效应制备微色谱柱检测仪,检测2类农药.结果 该方法可以对有机磷农药和氨基甲酸酯类农药作出快速的定性分析,且最低检出量可达到10 μg.结论 该法操作简便,高效,重现性好,且试剂用量少,是批量农药样品定性检测和突发农药中毒事件现场快速筛选的一种新方法.%[Objective]To establish the method for rapid filtering organophosphorus pesticides and carbamate pesticides.[Methods]Based on the principle of thin-layer chromatography, the micro-column detector was prepared by using capillary effect, and was used to detect 2 kinds of pesticides.[Results]The method could make qualitative and quantitative analysis of organophosphorus peaticides and carbamate pesticides, and the minimum detection limit was 10 μg.[Conclusion]The method is simple, efficient, reproducible, with less reagent consumption, and it is a new method for qualitative detection of bulk samples of pesticides and rapid pesticide poisoning filtering in emergency incident.

  8. Validation and use of a fast sample preparation method and liquid chromatography-tandem mass spectrometry in analysis of ultra-trace levels of 98 organophosphorus pesticide and carbamate residues in a total diet study involving diversified food types.

    Chung, Stephen W C; Chan, Benny T P

    2010-07-16

    This paper reports a comprehensive sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, identification and quantitation of 73 pesticides and their related products, a total of 98 analytes, belonging to organophosphorus pesticides (OPPs) and carbamates, in foods. The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rigged, and safe) procedure that combines isolation of the pesticides and sample clean-up in a single step. Analysis is performed by liquid chromatography-electrospray ionization-tandem mass spectrometry operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Two main fragment ions for each pesticide were obtained to achieve the identification according to the SANCO guidelines 10684/2009. The method was validated with various food samples, including edible oil, meat, egg, cheese, chocolate, coffee, rice, tree nuts, citric fruits, vegetables, etc. No significant matrix effect was observed for tested pesticides, therefore, matrix-matched calibration was not necessary. Calibration curves were linear and covered from 1 to 20 microg L(-1) for all compounds studied. The average recoveries, measured at 10 microg kg(-1), were in the range 70-120% for all of the compounds tested with relative standard deviations below 20%, while a value of 10 microg kg(-1) has been established as the method limit of quantitation (MLOQ) for all target analytes. Similar trueness and precision results were also obtained for spiking at 200 microg kg(-1). Expanded uncertainty values were in the range 21-27% while the HorRat ratios were below 1. The method has been successfully applied to the analysis of 700 food samples in the course of a baseline monitoring study of OPPs and carbamates. PMID:20557892

  9. Absence of pyroglutamyl-Nsup(3im)-methyl-histidyl-prolineamide (methyl-thyrotrophin releasing hormone) in the rat hypothalamus

    Methyl-TRH is a potent synthetic analogue of TRH. Nsup(3im)-methyl-histidine is present in mammalian brain and it has been suggested that methyl-TRH is a physiological releasing hormone normally present in the hypothalamus. A non-gradient cation-exchange chromatography system that uses SP-Sephadex C-25 and completely resolves methyl-TRH and TRH has been developed. Because methyl-TRH cross-reacts in the immunoassay for TRH, this assay was used to measure TRH and methyl-TRH in the chromatographic fractions. By this means it has been demonstrated that the amount of methyl-TRH present in the rat is less that 0.025ng/hypothalamus. (author)

  10. EFS shows biallelic methylation in uveal melanoma with poor prognosis as well as tissue-specific methylation

    Uveal melanoma (UM) is a rare eye tumor. There are two classes of UM, which can be discriminated by the chromosome 3 status or global mRNA expression profile. Metastatic progression is predominantly originated from class II tumors or from tumors showing loss of an entire chromosome 3 (monosomy 3). We performed detailed EFS (embryonal Fyn-associated substrate) methylation analyses in UM, cultured uveal melanocytes and normal tissues, to explore the role of the differentially methylated EFS promoter region CpG island in tumor classification and metastatic progression. EFS methylation was determined by direct sequencing of PCR products from bisulfite-treated DNA or by sequence analysis of individual cloned PCR products. The results were associated with clinical features of tumors and tumor-related death of patients. Analysis of 16 UM showed full methylation of the EFS CpG island in 8 (50%), no methylation in 5 (31%) and partial methylation in 3 (19%) tumors. Kaplan-Meier analysis revealed a higher risk of metastatic progression for tumors with EFS methylation (p = 0.02). This correlation was confirmed in an independent set of 24 randomly chosen tumors. Notably, only UM with EFS methylation gave rise to metastases. Real-time quantitative RT-PCR expression analysis revealed a significant inverse correlation of EFS mRNA expression with EFS methylation in UM. We further found that EFS methylation is tissue-specific with full methylation in peripheral blood cells, and no methylation in sperm, cultured primary fibroblasts and fetal muscle, kidney and brain. Adult brain samples, cultured melanocytes from the uveal tract, fetal liver and 3 of 4 buccal swab samples showed partial methylation. EFS methylation always affects both alleles in normal and tumor samples. Biallelic EFS methylation is likely to be the result of a site-directed methylation mechanism. Based on partial methylation as observed in cultured melanocytes we hypothesize that there might be methylated and

  11. Regulated DNA Methylation and the Circadian Clock: Implications in Cancer

    Tammy M. Joska

    2014-09-01

    Full Text Available Since the cloning and discovery of DNA methyltransferases (DNMT, there has been a growing interest in DNA methylation, its role as an epigenetic modification, how it is established and removed, along with the implications in development and disease. In recent years, it has become evident that dynamic DNA methylation accompanies the circadian clock and is found at clock genes in Neurospora, mice and cancer cells. The relationship among the circadian clock, cancer and DNA methylation at clock genes suggests a correlative indication that improper DNA methylation may influence clock gene expression, contributing to the etiology of cancer. The molecular mechanism underlying DNA methylation at clock loci is best studied in the filamentous fungi, Neurospora crassa, and recent data indicate a mechanism analogous to the RNA-dependent DNA methylation (RdDM or RNAi-mediated facultative heterochromatin. Although it is still unclear, DNA methylation at clock genes may function as a terminal modification that serves to prevent the regulated removal of histone modifications. In this capacity, aberrant DNA methylation may serve as a readout of misregulated clock genes and not as the causative agent. This review explores the implications of DNA methylation at clock loci and describes what is currently known regarding the molecular mechanism underlying DNA methylation at circadian clock genes.

  12. Adsorption sites and rotational tunneling of methyl groups in cubic I methyl fluoride water clathrate

    Prager, M.; Baumert, J.; Press, W.; Plazanet, M.; J. S. Tse; Klug, D. D.

    2005-01-01

    Neutron spectroscopy in the mueV and meV regime and quasielastic scattering is applied to characterize the dynamics of methyl groups of methyl fluoride guest molecules in cubic I CH3F - water clathrate. Only above T similar to 60 K quasielastic spectra are unaffected by quantum effects. They are well described by two Lorentzians representing the CH3F species in the small and large cages of the structure. The intensities show that both cages are completely filled. The linear broadenings with t...

  13. Cytological study of DNA methylation and histone methylation patterns in human cell lines

    Skalníková, M.; Bártová, Eva; Kozubek, Stanislav; Kozubek, Michal

    Brno: Masarykova univerzita v Brně, 2004 - (Kozubek, S.; Kozubek, M.), s. 72-75 ISBN 80-210-3560-9. [Biophysics of the Genome. Brno (CZ), 12.10.2004-13.10.2004] R&D Projects: GA ČR GP202/03/D033; GA ČR GA202/04/0907; GA MZd NC6987; GA MZd 1A8241; GA AV ČR IAA5004306 Institutional research plan: CEZ:AV0Z5004920 Keywords : DNA methylation patterns * human cell lines * histone methylation patterns Subject RIV: BO - Biophysics

  14. Structure, function and carcinogenicity of metabolites of methylated and non-methylated polycyclic aromatic hydrocarbons: a comprehensive review.

    Flesher, James W; Lehner, Andreas F

    2016-03-01

    The Unified Theory of PAH Carcinogenicity accommodates the activities of methylated and non-methylated polycyclic aromatic hydrocarbons (PAHs) and states that substitution of methyl groups on meso-methyl substituted PAHs with hydroxy, acetoxy, chloride, bromide or sulfuric acid ester groups imparts potent cancer producing properties. It incorporates specific predictions from past researchers on the mechanism of carcinogenesis by methyl-substituted hydrocarbons, including (1) requirement for metabolism to an ArCH2X type structure where X is a good leaving group and (2) biological substitution of a meso-methyl group at the most reactive center in non-methylated hydrocarbons. The Theory incorporates strong inferences of Fieser: (1) The mechanism of carcinogenesis involves a specific metabolic substitution of a hydrocarbon at its most reactive center and (2) Metabolic elimination of a carcinogen is a detoxifying process competitive with that of carcinogenesis and occurring by a different mechanism. According to this outlook, chemical or biochemical substitution of a methyl group at the reactive meso-position of non-methylated hydrocarbons is the first step in the mechanism of carcinogenesis for most, if not all, PAHs and the most potent metabolites of PAHs are to be found among the meso methyl-substituted hydrocarbons. Some PAHs and their known or potential metabolites and closely related compounds have been tested in rats for production of sarcomas at the site of subcutaneous injection and the results strongly support the specific predictions of the Unified Theory. PMID:26894797

  15. An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion

    Sarathy, S M; Thomson, M J; Pitz, W J; Lu, T

    2010-02-19

    Biodiesel is typically a mixture of long chain fatty acid methyl esters for use in compression ignition engines. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This research study presents new combustion data for methyl decanoate in an opposed-flow diffusion flame. An improved detailed chemical kinetic model for methyl decanoate combustion is developed, which serves as the basis for deriving a skeletal mechanism via the direct relation graph method. The novel skeletal mechanism consists of 648 species and 2998 reactions. This mechanism well predicts the methyl decanoate opposed-flow diffusion flame data. The results from the flame simulations indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.

  16. 3-Methyl­anilinium hydrogen phthalate

    Liu, Ming-Liang

    2011-01-01

    The asymmetric unit of the title salt, C7H10N+·C8H5O4 −, consists of two 3-methyl­phenyl­ammonium cations and two hydrogen phthalate anions. There are strong intra­molecular O—H⋯O hydrogen bonds in the virtually planar (r.m.s. deviations = 0.054 Å) phthalate anions. In the crystal, the cations and anions are connected via an extensive sytem of N—H⋯O hydrogen bonds into a corrugated layer extended parallel to (001).

  17. Development of sunflower hybrids tolerant to tribenuron methyl

    Jocić Siniša; Malidža Goran; Cvejić Sandra; Hladni Nada; Miklič Vladimir; Škorić Dragan

    2011-01-01

    Discovery of tribenuron-methyl resistant wild Helianthus annuus L. population (ANN-KAN) created an opportunity for expansion of sunflower herbicide resistance breeding program. The aim of this study was development of sunflower hybrids resistant to tribenuron-methyl. Creation of tribenuron-methyl resistant hybrids would enable the use of a wider palette of herbicides for sunflower, more efficient chemical control of Cirsium arvense and more economically pro...

  18. Mercury Methylation by Dissimilatory Iron-Reducing Bacteria▿

    Kerin, E. J.; Gilmour, C C; Roden, E.; Suzuki, M T; Coates, J. D.; Mason, R P

    2006-01-01

    The Hg-methylating ability of dissimilatory iron-reducing bacteria in the genera Geobacter, Desulfuromonas, and Shewanella was examined. All of the Geobacter and Desulfuromonas strains tested methylated mercury while reducing Fe(III), nitrate, or fumarate. In contrast, none of the Shewanella strains produced methylmercury at higher levels than abiotic controls under similar culture conditions. Geobacter and Desulfuromonas are closely related to known Hg-methylating sulfate-reducing bacteria w...

  19. Widely variable endogenous retroviral methylation levels in human placenta

    Reiss, Daphne; Zhang, Ying; Mager, Dixie L.

    2007-01-01

    It is generally assumed that transposable elements, including endogenous retroviruses (ERVs), are silenced by DNA methylation/chromatin structure in mammalian cells. However, there have been very few experimental studies to examine the methylation status of human ERVs. In this study, we determined and compared the methylation status of the 5′ long terminal repeats (LTRs) of different copies of the human endogenous retrovirus (HERV) family HERV-E, which are inserted in various genomic contexts...

  20. Maternal methyl supplemented diets and effects on offspring health

    O'Neill, Rachel J.; Vrana, Paul B.; Rosenfeld, Cheryl S.

    2014-01-01

    Women seeking to become pregnant and pregnant women are currently advised to consume high amounts of folic acid and other methyl donors to prevent neural tube defects in their offspring. These diets can alter methylation patterns of several biomolecules, including nucleic acids, and histone proteins. Limited animal model data suggests that developmental exposure to these maternal methyl supplemented (MS) diets leads to beneficial epimutations. However, other rodent and humans studies have yie...

  1. Methylated DNA Immunoprecipitation Analysis of Mammalian Endogenous Retroviruses.

    Rebollo, Rita; Mager, Dixie L

    2016-01-01

    Endogenous retroviruses are repetitive sequences found abundantly in mammalian genomes which are capable of modulating host gene expression. Nevertheless, most endogenous retrovirus copies are under tight epigenetic control via histone-repressive modifications and DNA methylation. Here we describe a common method used in our laboratory to detect, quantify, and compare mammalian endogenous retrovirus DNA methylation. More specifically we describe methylated DNA immunoprecipitation (MeDIP) followed by quantitative PCR. PMID:26895065

  2. Synthesis and pharmacological activities of 2-methyl-8-quinolyloxypropylamines

    Reddy YSR

    2007-01-01

    Full Text Available Starting chloropropane derivative (2 was prepared by the reaction of 2-methyl-8-hydroxyquinoline (1 with 1- bromo-3-chloropropane in presence of a base. Various new 1-(2-methyl-8-quinolyloxy-3-propylamines (3a-3j have been synthesized by the condensation of 1-(2-methyl-8-quinolyloxy-3-chloropropane (2 with different amines. Compounds were screened for the possible central nervous system depressant activities. Some of them showed moderate central nervous system depressant activity.

  3. Methylation of the chicken vitellogenin gene: influence of estradiol administration.

    Meijlink, F C; Philipsen, J N; Gruber, M; AB, G

    1983-01-01

    The degree of methylation of the chicken vitellogenin gene has been investigated. Upon induction by administration of estradiol to a rooster, methyl groups at specific sites near the 5'-end of the gene are eliminated. The process of demethylation is slower than the activation of the gene. Demethylation is therefore probably not a prerequisite to gene transcription. At least two other sites in the coding region of the gene are methylated in the liver of estrogenized roosters, but not in the li...

  4. Folding-promoted methylation of a helical DMAP analogue.

    Heemstra, Jennifer M; Moore, Jeffrey S

    2004-02-18

    The methylation rate for a series of pyridine-containing phenylene ethynylene oligomers shows a nonlinear dependence on chain length, with a significant rate enhancement observed for oligomers that adopt a folded, helical conformation. The folded structure provides a microenvironment that lowers the energy barrier for the methylation reaction. Of these noncovalent interactions, the largest stabilization may arise from binding of methyl iodide in the hydrophobic cavity of the folded oligomer, in close proximity to the pyridine nucleophile. PMID:14871092

  5. Quantitative methylation-specific PCR - optimization and application

    Pharo, Heidi Dietrichson

    2014-01-01

    Aberrant DNA methylation is one of the most common alterations in cancer, and a vast diversity of methods for its investigation exists. Quantitative methylation-specific PCR (qMSP) is frequently used to estimate the amounts of methylation at specific loci, such as gene promoters. However, diverging qMSP results are being reported in the literature, underscoring the need for standardization of the individual steps of the protocol. In this study we aimed at identifying the most likely sources o...

  6. A DNA methylation fingerprint of 1628 human samples

    Fernandez, A. F.; Assenov, Y.; Martin-Subero, J.I. (José Ignacio); Balint, B.; Siebert, R.; Taniguchi, H; Yamamoto, H.; M. Hidalgo; Tan, A.-C.; Galm, O; Ferrer, I.; Sanchez-Cespedes, M.; Villanueva, A; Carmona, J; Sanchez-Mut, J. V.

    2012-01-01

    Most of the studies characterizing DNA methylation patterns have been restricted to particular genomic loci in a limited number of human samples and pathological conditions. Herein, we present a compromise between an extremely comprehensive study of a human sample population with an intermediate level of resolution of CpGs at the genomic level. We obtained a DNA methylation fingerprint of 1628 human samples in which we interrogated 1505 CpG sites. The DNA methylation patterns reve...

  7. Research and application progress of MGMT promoter methylation in gliomas

    Cui-yun SUN; Shi-zhu YU

    2014-01-01

    O6-methylguanine-DNA methyltransferase (MGMT) is an important DNA repair enzyme. The promoter methylation status of MGMT gene has recently become a biomarker of gliomas. Methylation of the MGMT promoter not only is an important biomarker to evaluate the sensitivity to the chemotherapy with alkylating agents, but also contributes to predicting prognosis and distinguishing between recurrence and pseudoprogression in glioma patients. Especially in the elderly, MGMT promoter methylation stat...

  8. Differential DNA Methylation Analysis without a Reference Genome

    Johanna Klughammer; Paul Datlinger; Dieter Printz; Nathan C. Sheffield; Matthias Farlik; Johanna Hadler; Gerhard Fritsch; Christoph Bock

    2015-01-01

    Summary Genome-wide DNA methylation mapping uncovers epigenetic changes associated with animal development, environmental adaptation, and species evolution. To address the lack of high-throughput methods for DNA methylation analysis in non-model organisms, we developed an integrated approach for studying DNA methylation differences independent of a reference genome. Experimentally, our method relies on an optimized 96-well protocol for reduced representation bisulfite sequencing (RRBS), which...

  9. Novel PdCI 2 (RuCI 3)/ZrO2SO3 Catalysts for Synthesis of Carbamates by Oxidative Carbonylation of Amines%一种胺氧化羰化制氨基甲酸酯新催化剂体系

    石峰; 司马天龙; 邓友全

    2000-01-01

    Novel combined PdC12 (RuCl3) with ZrO2-SO3 catalysts were developed for the synthesis of carbamates by oxidative carbonylation of aliphatic and aromatic amines. At 170 ℃ and 4.0 MPa, oxidative carbonylation of aromatic amines to the corresponding carbamates over this catalyst system could be proceeded with a high conversion and selectivity. Especially when β-naphthylamine was used as the substrate, 100% conversion and 95% selectivity were obtained in only 15 min. The catalytic performance of PdCl2/ZrO2-SO3 was better than that of RuCl3/ZrO2-SO3 for such oxidative carbonylation reaction.Possible role of ZrO2-SO3 as co-catalyst was also conjectured.

  10. Formation of Methyl Acrylate from CO 2 and Ethylene via Methylation of Nickelalactones

    Bruckmeier, Christian

    2010-05-24

    The nickel-induced coupling of ethylene and CO2 represents a promising pathway toward acrylates. To overcome the high bond dissociation energies of the M-O moieties, we worked out an in situ methylation of nickelalactones to realize the β-hydride elimination and the liberation of the acrylate species. © 2010 American Chemical Society.

  11. Osteoponin Promoter Controlled by DNA Methylation: Aberrant Methylation in Cloned Porcine Genome

    Chih-Jie Shen

    2014-01-01

    Full Text Available Cloned animals usually exhibited many defects in physical characteristics or aberrant epigenetic reprogramming, especially in some important organ development. Osteoponin (OPN is an extracellular-matrix protein involved in heart and bone development and diseases. In this study, we investigated the correlation between OPN mRNA and its promoter methylation changes by the 5-aza-dc treatment in fibroblast cell and promoter assay. Aberrant methylation of porcine OPN was frequently found in different tissues of somatic nuclear transferred cloning pigs, and bisulfite sequence data suggested that the OPN promoter region −2615 to −2239 nucleotides (nt may be a crucial regulation DNA element. In pig ear fibroblast cell culture study, the demethylation of OPN promoter was found in dose-dependent response of 5-aza-dc treatment and followed the OPN mRNA reexpression. In cloned pig study, discrepant expression pattern was identified in several cloned pig tissues, especially in brain, heart, and ear. Promoter assay data revealed that four methylated CpG sites presenting in the −2615 to −2239 nt region cause significant downregulation of OPN promoter activity. These data suggested that methylation in the OPN promoter plays a crucial role in the regulation of OPN expression that we found in cloned pigs genome.

  12. Global hypomethylation and promoter methylation in small intestinal neuroendocrine tumors

    Fotouhi, Omid; Adel Fahmideh, Maral; Kjellman, Magnus; Sulaiman, Luqman; Höög, Anders; Zedenius, Jan; Hashemi, Jamileh; Larsson, Catharina

    2014-01-01

    Aberrant DNA methylation is a feature of human cancer affecting gene expression and tumor phenotype. Here, we quantified promoter methylation of candidate genes and global methylation in 44 small intestinal-neuroendocrine tumors (SI-NETs) from 33 patients by pyrosequencing. Findings were compared with gene expression, patient outcome and known tumor copy number alterations. Promoter methylation was observed for WIF1, RASSF1A, CTNNB1, CXCL14, NKX2–3, P16, LAMA1, and CDH1. By contrast APC, CDH3...

  13. DNA methylation profiles in preeclampsia and healthy control placentas.

    Yeung, Kristen R; Chiu, Christine L; Pidsley, Ruth; Makris, Angela; Hennessy, Annemarie; Lind, Joanne M

    2016-05-15

    Preeclampsia is a hypertensive disorder of pregnancy that affects 3-5% of all pregnancies. There is evidence to suggest that epigenetic mechanisms, such as DNA methylation, play a role in placental development and function. This study compared DNA methylation profiles of placentas from preeclampsia-affected pregnancies with placentas from healthy pregnancies to identify gene-specific changes in DNA methylation that may contribute to the development of preeclampsia. The methylation status of eight placental biopsies taken from preeclampsia-affected and 16 healthy pregnancies was analyzed using the Illumina Infinium Methylation 450 BeadChip array. Bisulfite pyrosequencing was used to confirm regions found to be differentially methylated between preeclampsia and healthy placentas. A total of 303 differentially methylated regions, 214 hypermethylated and 89 hypomethylated, between preeclampsia cases and controls were identified, after adjusting for gestational age (adjusted P Functional annotation found cell adhesion, wingless type MMTV Integration Site family member 2 (Wnt) signaling pathway, and regulation of transcription were significantly enriched in these gene regions. Hypermethylation of WNT2, sperm equatorial segment protein (SPESP1), NADPH oxidase 5 (NOX5), and activated leukocyte cell adhesion molecule (ALCAM) in preeclampsia placentas was confirmed with pyrosequencing. This study found differences in methylation in gene regions involved in cell signaling (WNT2), fertilization and implantation (SPESP1), reactive oxygen species signaling (NOX5), and cell adhesion (ALCAM). These results build on recently published studies that have reported significant differences in DNA methylation in preeclampsia placentas. PMID:26968548

  14. Quantitation of DNA methylation by melt curve analysis

    Jones Michael E

    2009-04-01

    Full Text Available Abstract Background Methylation of DNA is a common mechanism for silencing genes, and aberrant methylation is increasingly being implicated in many diseases such as cancer. There is a need for robust, inexpensive methods to quantitate methylation across a region containing a number of CpGs. We describe and validate a rapid, in-tube method to quantitate DNA methylation using the melt data obtained following amplification of bisulfite modified DNA in a real-time thermocycler. Methods We first describe a mathematical method to normalise the raw fluorescence data generated by heating the amplified bisulfite modified DNA. From this normalised data the temperatures at which melting begins and finishes can be calculated, which reflect the less and more methylated template molecules present respectively. Also the T50, the temperature at which half the amplicons are melted, which represents the summative methylation of all the CpGs in the template mixture, can be calculated. These parameters describe the methylation characteristics of the region amplified in the original sample. Results For validation we used synthesized oligonucleotides and DNA from fresh cells and formalin fixed paraffin embedded tissue, each with known methylation. Using our quantitation we could distinguish between unmethylated, partially methylated and fully methylated oligonucleotides mixed in varying ratios. There was a linear relationship between T50 and the dilution of methylated into unmethylated DNA. We could quantitate the change in methylation over time in cell lines treated with the demethylating drug 5-aza-2'-deoxycytidine, and the differences in methylation associated with complete, clonal or no loss of MGMT expression in formalin fixed paraffin embedded tissues. Conclusion We have validated a rapid, simple in-tube method to quantify methylation which is robust and reproducible, utilizes easily designed primers and does not need proprietary algorithms or software. The

  15. Evidence for non-CpG methylation in mammals

    Yan, Jie; Zierath, Juleen R; Barres, Romain

    2011-01-01

    In mammals, the existence of cytosine methylation on non-CpG sequences is controversial. Here, we adapted a LuminoMetric-based Assay (LUMA) to determine global non-CpG methylation levels in rodent and human tissues. We observed that......In mammals, the existence of cytosine methylation on non-CpG sequences is controversial. Here, we adapted a LuminoMetric-based Assay (LUMA) to determine global non-CpG methylation levels in rodent and human tissues. We observed that...

  16. A review on environmental factors regulating arsenic methylation in humans

    Subjects exposed to arsenic show significant inter-individual variation in urinary patterns of arsenic metabolites but insignificant day-to-day intra-individual variation. The inter-individual variation in arsenic methylation can be partly responsible for the variation in susceptibility to arsenic toxicity. Wide inter-ethnic variation and family correlation in urinary arsenic profile suggest a genetic effect on arsenic metabolism. In this paper the environmental factors affecting arsenic metabolism are reviewed. Methylation capacity might reduce with increasing dosage of arsenic exposure. Furthermore, women, especially at pregnancy, have better methylation capacity than their men counterparts, probably due to the effect of estrogen. Children might have better methylation capacity than adults and age shows inconsistent relevance in adults. Smoking and alcohol consumption might be associated with a poorer methylation capacity. Nutritional status is important in the methylation capacity and folate may facilitate the methylation and excretion of arsenic. Besides, general health conditions and medications might influence the arsenic methylation capacity; and technical problems can cause biased estimates. The consumption of seafood, seaweed, rice and other food with high arsenic contents and the extent of cooking and arsenic-containing water used in food preparation may also interfere with the presentation of the urinary arsenic profile. Future studies are necessary to clarify the effects of the various arsenic metabolites including the trivalent methylated forms on the development of arsenic-induced human diseases with the consideration of the effects of confounding factors and the interactions with other effect modifiers

  17. Theoretical spectroscopic characterization at low temperatures of S-methyl thioformate and O-methyl thioformate

    Senent, M. L., E-mail: senent@iem.cfmac.csic.es [Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid 28006 (Spain); Puzzarini, C., E-mail: cristina.puzzarini@unibo.it [Dipartimento di Chimica G. Ciamician, Università di Bologna, Via F. Selmi 2, I-40126 Bologna (Italy); Hochlaf, M., E-mail: hochlaf@univ-mlv.fr [Laboratoire de Modélisation et Simulation Multi Echelle, Université Paris-Est, MSME UMR 8208 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallée (France); Domínguez-Gómez, R., E-mail: rosa.dominguez@upm.es [Departamento de Ingeniería Civil, Cátedra de Química, E.U.I.T. Obras Públicas, Universidad Politécnica de Madrid, Madrid (Spain); Carvajal, M., E-mail: miguel.carvajal@dfa.uhu.es [Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Unidad Asociada IEM-CSIC-U.Huelva, Universidad de Huelva, 21071 Huelva (Spain)

    2014-09-14

    Highly correlated ab initio methods are employed to determine spectroscopic properties at low temperatures of two S-analogs of methyl formate: S-methyl thioformate CH{sub 3}-S-CHO (MSCHO) and O-methyl thioformate CH{sub 3}-O-CHS (MOCHS). Both species are detectable and they are expected to play an important role in Astrochemistry. Molecular properties are compared with those of the O-analog, methyl formate. Both isomers present two conformers cis and trans. cis-CH{sub 3}-S-CHO represents the most stable structure lying 4372.2 cm{sup −1} below cis-CH{sub 3}-O-CHS. The energy difference between the cis and trans forms is drastically lower for MSCHO (1134 cm{sup −1}) than for MOCHS (1963.6 cm{sup −1}). Harmonic and anharmonic fundamentals and the corresponding intensities, as well as the rotational constants for the ground vibrational and first excited torsional states and the centrifugal distortions constants, are provided. Low torsional energy levels have been obtained by solving variationally a two dimensional Hamiltonian expressed in terms of the two torsional degrees of freedom. The corresponding 2D potential energy surfaces have been computed at the CCSD(T)/aug-cc-pVTZ level of theory. The methyl torsional barriers V{sub 3}(cis) are determined to be 139.7 cm{sup −1} (CH{sub 3}-S-CHO) and 670.4 cm{sup −1} (CH{sub 3}-O-CHS). The A/E splitting of ground torsional state has been estimated to be 0.438 cm{sup −1} for CH{sub 3}-S-CHO and negligible for CH{sub 3}-O-CHS.

  18. Assessing the efficiency and significance of Methylated DNA Immunoprecipitation (MeDIP) assays in using in vitro methylated genomic DNA

    Jia Jinsong; Pekowska Aleksandra; Jaeger Sebastien; Benoukraf Touati; Ferrier Pierre; Spicuglia Salvatore

    2010-01-01

    Abstract Background DNA methylation contributes to the regulation of gene expression during development and cellular differentiation. The recently developed Methylated DNA ImmunoPrecipitation (MeDIP) assay allows a comprehensive analysis of this epigenetic mark at the genomic level in normal and disease-derived cells. However, estimating the efficiency of the MeDIP technique is difficult without previous knowledge of the methylation status of a given cell population. Attempts to circumvent th...

  19. Methyl Complexes of the Transition Metals.

    Campos, Jesús; López-Serrano, Joaquín; Peloso, Riccardo; Carmona, Ernesto

    2016-05-01

    Organometallic chemistry can be considered as a wide area of knowledge that combines concepts of classic organic chemistry, that is, based essentially on carbon, with molecular inorganic chemistry, especially with coordination compounds. Transition-metal methyl complexes probably represent the simplest and most fundamental way to view how these two major areas of chemistry combine and merge into novel species with intriguing features in terms of reactivity, structure, and bonding. Citing more than 500 bibliographic references, this review aims to offer a concise view of recent advances in the field of transition-metal complexes containing M-CH3 fragments. Taking into account the impressive amount of data that are continuously provided by organometallic chemists in this area, this review is mainly focused on results of the last five years. After a panoramic overview on M-CH3 compounds of Groups 3 to 11, which includes the most recent landmark findings in this area, two further sections are dedicated to methyl-bridged complexes and reactivity. PMID:26991740

  20. Rotational Spectroscopy of Methyl Vinyl Ketone

    Zakharenko, Olena; Motiyenko, R. A.; Aviles Moreno, Juan-Ramon; Huet, T. R.

    2015-06-01

    Methyl vinyl ketone, MVK, along with previously studied by our team methacrolein, is a major oxidation product of isoprene, which is one of the primary contributors to annual global VOC emissions. In this talk we present the analysis of the rotational spectrum of MVK recorded at room temperature in the 50 -- 650 GHz region using the Lille spectrometer. The spectroscopic characterization of MVK ground state will be useful in the detailed analysis of high resolution infrared spectra. Our study is supported by high level quantum chemical calculations to model the structure of the two stable s-trans and s-cis conformers and to obtain the harmonic force field parameters, internal rotation barrier heights, and vibrational frequencies. In the Doppler-limited spectra the splittings due to the internal rotation of methyl group are resolved, therefore for analysis of this molecule we used the Rho-Axis-Method Hamiltonian and RAM36 code to fit the rotational transitions. At the present time the ground state of two conformers is analyzed. Also we intend to study some low lying excited states. The analysis is in progress and the latest results will be presented. Support from the French Laboratoire d'Excellence CaPPA (Chemical and Physical Properties of the Atmosphere) through contract ANR-10-LABX-0005 of the Programme d'Investissements d'Avenir is acknowledged.

  1. Automated sequence- and stereo-specific assignment of methyl-labeled proteins by paramagnetic relaxation and methyl-methyl nuclear overhauser enhancement spectroscopy

    Venditti, Vincenzo; Fawzi, Nicolas L.; Clore, G. Marius, E-mail: mariusc@mail.nih.gov [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Laboratory of Chemical Physics (United States)

    2011-11-15

    Methyl-transverse relaxation optimized spectroscopy is rapidly becoming the preferred NMR technique for probing structure and dynamics of very large proteins up to {approx}1 MDa in molecular size. Data interpretation, however, necessitates assignment of methyl groups which still presents a very challenging and time-consuming process. Here we demonstrate that, in combination with a known 3D structure, paramagnetic relaxation enhancement (PRE), induced by nitroxide spin-labels incorporated at only a few surface-exposed engineered cysteines, provides fast, straightforward and robust access to methyl group resonance assignments, including stereoassignments for the methyl groups of leucine and valine. Neither prior assignments, including backbone assignments, for the protein, nor experiments that transfer magnetization between methyl groups and the protein backbone, are required. PRE-derived assignments are refined by 4D methyl-methyl nuclear Overhauser enhancement data, eliminating ambiguities and errors that may arise due to the high sensitivity of PREs to the potential presence of sparsely-populated transient states.

  2. Effects of methyl p-hydroxybenzoate (methyl paraben) on Ca2+ concentration and histamine release in rat peritoneal mast cells

    Fukugasako, Sanae; ITO, SHINICHI; Ikemoto, Yoshimi

    2003-01-01

    Mechanisms of methyl p-hydroxybenzoate (methyl paraben) action in allergic reactions were investigated by measuring the intracellular Ca2+ concentration ([Ca2+]i) and histamine release in rat peritoneal mast cells (RPMCs).In the presence or absence of extracellular Ca2+, methyl paraben (0.1–10 mM) increased [Ca2+]i, in a concentration-dependent manner. Under both the conditions, methyl paraben alone did not evoke histamine release.In RPMCs pretreated with a protein kinase C (PKC) activator (p...

  3. Adaptation of an automated [11C]methylation system for the loop labeling method using [11C]methyl triflate

    An automated system for preparation of 11C-methylated compounds from [11C]methyl iodide, manufactured by Sumitomo Heavy Industries Ltd., was adapted for the loop labeling method using [11C]methyl triflate. Two 2-way valves on an exchangeable tray were replaced with 3-way valves and a furnace for heating an AgOTf column at 200 deg C was added. The automated system successfully produced [11C]raclopride and [11C]N-methyl-3-piperidyl benzilate in 0.96-1.1 GBq and 1.0-1.3 GBq, respectively, at 40 min after the end of bombardment. (author)

  4. METHYLATION PATTERN OF LRP15 GENE IN LEUKEMIA

    2007-01-01

    Objective To investigate the methylation status of LRP15 gene in acute leukemia (AL) patients and its role in the tumorigenesis.Methods The methylation of LRP15 promoter and first exon of bone marrow mononuclear cells in 73 patients with AL, 10 with chronic leukemia (CL), 9 with hematological benign diseases, and 20 healthy transplantation donors was analyzed by using methylation specific polymerase chain reaction. The methylation of LRP15 gene promoter and first exon in COS7, K562, and HL60 cell lines was also assayed.Results No LRP15 gene promoter methylation was detected in COS7 cell line. LRP15 gene promoter was methylated in K562 and HL60 cell lines. No deletion of LRP15 gene was detected in all samples. In nearly all French-American-British leukemia subtypes, we found that frequency of LRP15 methylation in adult patients with AL was 71.23%( 52/73 ). There was no detectable methylation in any of the 20 healthy donors and 8 chronic myeloid leukemia patients.The difference in frequency of LRP15 methylation between AL patients and healthy donors or CL patients ( 10. 00%,1/10) was significant (P < 0. 01 ). Hypermethylation of LRP15 gene was found in 57. 14% (16/28) of newly diagnosed AL patients, 83.33% of relapsed AL patients respectively, which was significantly different ( P < 0. 05). We also demonstrated LRP15 methylation in 55.56% (5/9) adults with benign hematological diseases.Conclusions LRP15 methylation changes are common abnormalities in leukemia. LRP15 is postulated to be a tumor suppressor gene.

  5. Oxidative stability and ignition quality of algae derived methyl esters containing varying levels of methyl eicosapentaenoate and methyl docosahexaenoate

    Bucy, Harrison

    Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Additionally, microalgae also do not compete with food and can be cultivated with wastewater on non-arable land. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. FAME biodiesel), renewable diesel, renewable gasoline, or jet fuel. For microalgae derived FAME, the fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chainpolyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is known that oxidative stability and cetane number decrease with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability and ignition quality of algae-based FAME with varying levels of EPA and DHA removal. Oxidative stability tests were conducted at a temperature of 110°C and airflow of 10 L/h using a Metrohm 743 Rancimat with automatic induction period determination following the EN 14112 Method from the ASTM D6751 and EN 14214

  6. (S-(Z-Methyl 2-[2,3-bis(benzyloxycarbonylguanidino]-4-methylpentanoate

    Frank R. Fronczek

    2011-01-01

    Full Text Available The title molecule, C24H29N3O6, has a nearly planar ten-atom C3N3O4 core, on account of both N—H groups forming six-membered-ring intramolecular hydrogen bonds to carbamate carbonyl O atoms. The absolute configuration was determined from resonant scattering of light atoms in Mo Kα radiation, agreeing with the configuration of starting materials.

  7. DNA methylation studies using twins: what are they telling us?

    Bell, Jordana T.; Spector, Tim D

    2012-01-01

    Recent studies have identified both heritable DNA methylation effects and differential methylation in disease-discordant identical twins. Larger sample sizes, replication, genetic-epigenetic analyses and longitudinal assays are now needed to establish the role of epigenetic variants in disease.

  8. Development of sunflower hybrids tolerant to tribenuron methyl

    Jocić Siniša

    2011-01-01

    Full Text Available Discovery of tribenuron-methyl resistant wild Helianthus annuus L. population (ANN-KAN created an opportunity for expansion of sunflower herbicide resistance breeding program. The aim of this study was development of sunflower hybrids resistant to tribenuron-methyl. Creation of tribenuron-methyl resistant hybrids would enable the use of a wider palette of herbicides for sunflower, more efficient chemical control of Cirsium arvense and more economically profitable post-emergence control of some annual broad-leaves weeds in sunflower. Original populations SURES-1 and SURES-2 are homozygous for resistance to tribenuron-methyl. F1 generations produced from the crossings are completely resistant to tribenuron-methyl, pointing out to dominant way of inheritance of this trait. Studies on the exact number of genes controlling the resistance are in progress. Tribenuron-methyl resistance was transferred from original populations into a number of female and male inbred lines of cultivated sunflower. These inbred lines could enable creation of a number of hybrids resistant to tribenuron-methyl. Hybrids SUMO-1-PR, SUMO-2- OR and SUMO-3 are resistant to doubled application dose of tribenuron-methyl. Agronomical characteristics of these hybrids are on the level with the leading conventional sunflower hybrids.

  9. Biological meaning of the methyl eugenol to fruit flies

    Tachi, S.; Subahar, S

    1998-12-16

    The objective of this research is to test a hypothesis whether methyl eugenol has a benefit in sexual selection of fruit flies and to find at what age the male flies respond to methyl eugenol. This test was conducted using carambola fruit fly (Bractocera carambolae) at Inter University Center for Life Science of ITB. The results of the tests are summarized as follows ; 1. Males started to respond to methyl eugenol at the age of 11 days old and the maximum number of males were recorded on 14 and 15 days old. 2. Most of the carambola fruit fly start to respond to methyl eugenol before they become sexually mature. 3. A very small percentage of newly emerged males (less than 1%) survive to mate with females during treatment with methyl eugenol. Methyl eugenol has benefit in sexual selection of carabola fruit fly, i.e., males responded to methyl eugenol before they engage in sexual activities, while females responded to methyl eugenol only when males started their mating activities. (author)

  10. DNA methylation characteristics of primary melanomas with distinct biological behaviour.

    Szilvia Ecsedi

    Full Text Available In melanoma, the presence of promoter related hypermethylation has previously been reported, however, no methylation-based distinction has been drawn among the diverse melanoma subtypes. Here, we investigated DNA methylation changes associated with melanoma progression and links between methylation patterns and other types of somatic alterations, including the most frequent mutations and DNA copy number changes. Our results revealed that the methylome, presenting in early stage samples and associated with the BRAF(V600E mutation, gradually decreased in the medium and late stages of the disease. An inverse relationship among the other predefined groups and promoter methylation was also revealed except for histologic subtype, whereas the more aggressive, nodular subtype melanomas exhibited hypermethylation as well. The Breslow thickness, which is a continuous variable, allowed for the most precise insight into how promoter methylation decreases from stage to stage. Integrating our methylation results with a high-throughput copy number alteration dataset, local correlations were detected in the MYB and EYA4 genes. With regard to the effects of DNA hypermethylation on melanoma patients' survival, correcting for clinical cofounders, only the KIT gene was associated with a lower overall survival rate. In this study, we demonstrate the strong influence of promoter localized DNA methylation changes on melanoma initiation and show how hypermethylation decreases in melanomas associated with less favourable clinical outcomes. Furthermore, we establish the methylation pattern as part of an integrated apparatus of somatic DNA alterations.

  11. KNaY-zeolite catalyzed dehydration of methyl lactate

    Hai Feng Shi; Yao Chi Hu; Yang Wang; He Huang

    2007-01-01

    A promising catalyst, KNaY was prepared by an ion exchange method with aqueous potassium chloride solution. Compared with NaY, KNaY was an effective catalyst for the dehydration of methyl lactate to methyl acrylate. Under the optimized conditions,an improved yield of 37.9 mol% was achieved.

  12. DNA methylation of SPARC and chronic low back pain

    Dashwood Thomas

    2011-08-01

    Full Text Available Abstract Background The extracellular matrix protein SPARC (Secreted Protein, Acidic, Rich in Cysteine has been linked to degeneration of the intervertebral discs and chronic low back pain (LBP. In humans, SPARC protein expression is decreased as a function of age and disc degeneration. In mice, inactivation of the SPARC gene results in the development of accelerated age-dependent disc degeneration concurrent with age-dependent behavioral signs of chronic LBP. DNA methylation is the covalent modification of DNA by addition of methyl moieties to cytosines in DNA. DNA methylation plays an important role in programming of gene expression, including in the dynamic regulation of changes in gene expression in response to aging and environmental signals. We tested the hypothesis that DNA methylation down-regulates SPARC expression in chronic LBP in pre-clinical models and in patients with chronic LBP. Results Our data shows that aging mice develop anatomical and behavioral signs of disc degeneration and back pain, decreased SPARC expression and increased methylation of the SPARC promoter. In parallel, we show that human subjects with back pain exhibit signs of disc degeneration and increased methylation of the SPARC promoter. Methylation of either the human or mouse SPARC promoter silences its activity in transient transfection assays. Conclusions This study provides the first evidence that DNA methylation of a single gene plays a role in chronic pain in humans and animal models. This has important implications for understanding the mechanisms involved in chronic pain and for pain therapy.

  13. Degradation of Methyl Iodide in Soil: Effects of Environmental Factors

    Methyl iodide (MeI) is a promising alternative to the phased-out fumigant methyl bromide, and its environmental fate following soil fumigation is of great concern. Experiments were conducted to investigate the effect of various environmental factors on the degradation rate of MeI in soil. The chem...

  14. Experimental research on performance of gaseous methyl iodide removal

    Under the circumstance of gaseous methyl iodide removal process in containment venting system, taking the deionized water and alkalescent sodium thiosulphate as absorber, the experimental researches on the performance of gaseous methyl iodide removal were carried out at different solution temperatures and concentrations. And the effects of two types of mechanisms, namely mass transfer and chemical reaction, on gaseous methyl iodide removal process were analyzed based on the experimental results. The research results show that at room temperature, the mass transfer mechanism plays a dominant role in gaseous methyl iodide removal process through the absorption of alkalescent sodium thiosulphate solution. Thus, the slow chemical reaction rate is the major factor that limits gaseous methyl iodide removal efficiency. With temperature increasing, the effect of chemical reaction is constantly enhanced in the methyl iodide removal process. However, the gas absorption process will get into an insensitive region when the reaction rate reaches to a certain point and the continuously enhancing chemical reaction rate will not greatly influence the removal efficiency. At that point, mass transfer performance becomes the major factor that limits gaseous methyl iodide removal process. The efficiency of gaseous methyl iodide removal can be further improved by necessary means of enhancing mass transfer process through increasing contact surface and so on. (authors)

  15. TET1 and hydroxymethylcytosine in transcription and DNA methylation fidelity

    Williams, Kristine; Christensen, Jesper; Pedersen, Marianne Terndrup;

    2011-01-01

    Enzymes catalysing the methylation of the 5-position of cytosine (mC) have essential roles in regulating gene expression and maintaining cellular identity. Recently, TET1 was found to hydroxylate the methyl group of mC, converting it to 5-hydroxymethyl cytosine (hmC). Here we show that TET1 binds...

  16. Analysis of DNA Cytosine Methylation on Cotton under Salt Stress

    2008-01-01

    DNA methylation,especially methylation of cytosine in eukaryotic organisms,has been implicated in gene regulation,genomic imprinting,the timing of DNA replication,and determination of chromatin structure.It was reported that 6.5% of the whole cytosine residues in the nuclear DNA in higher

  17. Effects of cytosine methylation on transcription factor binding sites

    Medvedeva, Yulia A

    2014-03-26

    Background: DNA methylation in promoters is closely linked to downstream gene repression. However, whether DNA methylation is a cause or a consequence of gene repression remains an open question. If it is a cause, then DNA methylation may affect the affinity of transcription factors (TFs) for their binding sites (TFBSs). If it is a consequence, then gene repression caused by chromatin modification may be stabilized by DNA methylation. Until now, these two possibilities have been supported only by non-systematic evidence and they have not been tested on a wide range of TFs. An average promoter methylation is usually used in studies, whereas recent results suggested that methylation of individual cytosines can also be important.Results: We found that the methylation profiles of 16.6% of cytosines and the expression profiles of neighboring transcriptional start sites (TSSs) were significantly negatively correlated. We called the CpGs corresponding to such cytosines " traffic lights" We observed a strong selection against CpG " traffic lights" within TFBSs. The negative selection was stronger for transcriptional repressors as compared with transcriptional activators or multifunctional TFs as well as for core TFBS positions as compared with flanking TFBS positions.Conclusions: Our results indicate that direct and selective methylation of certain TFBS that prevents TF binding is restricted to special cases and cannot be considered as a general regulatory mechanism of transcription. 2013 Medvedeva et al.; licensee BioMed Central Ltd.

  18. Acute exercise remodels promoter methylation in human skeletal muscle

    Barrès, Romain; Yan, Jie; Egan, Brendan;

    2012-01-01

    DNA methylation is a covalent biochemical modification controlling chromatin structure and gene expression. Exercise elicits gene expression changes that trigger structural and metabolic adaptations in skeletal muscle. We determined whether DNA methylation plays a role in exercise-induced gene ex...

  19. Novel methyl transfer during chemotaxis in Bacillus subtilis

    If Bacillus subtilis is incubated in radioactive methionine in the absence of protein synthesis, the methyl-accepting chemotaxis proteins (MCPs) become radioactively methylated. If the bacteria are further incubated in excess nonradioactive methionine (cold-chased) and then given the attractant aspartate, the MCPs lose about half of their radioactivity due to turnover, in which lower specific activity methyl groups from S-adenosylmethionine (AdoMet) replace higher specific activity ones. Due to the cold-chase, the specific activity of the AdoMet pool is reduced at least 2-fold. If, later, the attractant is removed, higher specific activity methyl groups return to the MCPs. Thus, there must exist an unidentified methyl carrier than can reversibly receive methyl groups from the MCPs. In a similar experiment, labeled cells were transferred to a flow cell and exposed to addition and removal of attractant and of repellent. All four kinds of stimuli were found to cause methanol production. Bacterial with maximally labeled MCPs were exposed to many cycles of addition and removal of attractant; the maximum amount of radioactive methanol was evolved on the third, not the first, cycle. This result suggests that there is a precursor-product relationship between methyl groups on the MCPs and on the unidentified carrier, which might be the direct source of methanol. However, since no methanol was produced when a methyltransferase mutant, whose MCPs were unmethylated, was exposed to addition and removal of attractant or repellent, the methanol must ultimately derive from methylated MCPs

  20. Aberrant methylation of candidate tumor suppressor genes in neuroblastoma.

    Hoebeeck, Jasmien; Michels, Evi; Pattyn, Filip; Combaret, Valérie; Vermeulen, Joëlle; Yigit, Nurten; Hoyoux, Claire; Laureys, Geneviève; De Paepe, Anne; Speleman, Frank; Vandesompele, Jo

    2009-01-18

    CpG island hypermethylation has been recognized as an alternative mechanism for tumor suppressor gene inactivation. In this study, we performed methylation-specific PCR (MSP) to investigate the methylation status of 10 selected tumor suppressor genes in neuroblastoma. Seven of the investigated genes (CD44, RASSF1A, CASP8, PTEN, ZMYND10, CDH1, PRDM2) showed high frequencies (> or =30%) of methylation in 33 neuroblastoma cell lines. In 42 primary neuroblastoma tumors, the frequencies of methylation were 69%, CD44; 71%, RASSF1A; 56%, CASP8; 25%, PTEN; 15%, ZMYND10; 8%, CDH1; and 0%, PRDM2. Furthermore, CASP8 and CDH1 hypermethylation was significantly associated with poor event-free survival. Meta-analysis of 115 neuroblastoma tumors demonstrated a significant correlation between CASP8 methylation and MYCN amplification. In addition, there was a correlation between ZMYND10 methylation and MYCN amplification. The MSP data, together with optimized mRNA re-expression experiments (in terms of concentration and time of treatment and use of proper reference genes) further strengthen the notion that epigenetic alterations could play a significant role in NB oncogenesis. This study thus warrants the need for a global profiling of gene promoter hypermethylation to identify genome-wide aberrantly methylated genes in order to further understand neuroblastoma pathogenesis and to identify prognostic methylation markers. PMID:18819746