WorldWideScience

Sample records for acid synthesis characterisation

  1. [New biological active derivatives of indomethacin and acetylsalicylic acid. Synthesis, physico-chemical characterisation and structure validation].

    Science.gov (United States)

    Stan, Catalina; Stefanache, Alina; Dumitrache, M

    2006-01-01

    It is well known that niflumic acid glycinamide has a good antiinflammatory action useful in gum inflammatory diseases. The objective of this study was to obtain new glycinamides of acetylsalicylic acid and indomethacin, which could have a better antiinflammatory action than niflumic acid glycinamide. The study presents the synthesis, physico-chemical characterisation and structure validation of these glycinamides.

  2. Synthesis, characterisation and luminescent properties of lanthanide-organic polymers with picolinic and glutaric acids

    OpenAIRE

    Girginova, Penka I.; Paz, Filipe A. Almeida; Soares-Santos, Paula C. R.; Ferreira, R. A. Sá; Carlos, Luís D.; Amaral, Vítor S.; Klinowski, Jacek; Helena I. S. Nogueira; Trindade, Tito

    2007-01-01

    Three new lanthanide(III) complexes (Ln = Sm, Tb and Eu) of picolinic and glutaric acid were prepared and characterised. The crystal structure of the complex [Sm(glu)(pic)- (H2O)2] (where Hpic and H2glu stand for picolinic and glutaric acid, respectively) was determined by single-crystal Xray diffraction. All the Ln complexes were characterised by elemental analysis, infrared spectroscopy, X-ray powder diffraction and thermoanalytical measurements. The combined Introdu...

  3. Synthesis and characterisation of manganese oxides from potassium permanganate and citric acid mixtures

    Science.gov (United States)

    Burhanuddin, Syazwani; Yarmo, Ambar; Yamin, Bohari M.

    2013-11-01

    Reaction of KMnO4 and citric acid at different stoichiometric ratio found to give black precipitate after calcined at 500 %C. The black precipitate are classified as two type of manganese oxides mineral namely as bixbyite and hollandite. IR and XRD data were in agreement with the literature report.

  4. Transition Metal Complexes of 5-bromo Salicylaldehyde-2-furoic acid hydrazide; Synthesis and Characterisation

    Directory of Open Access Journals (Sweden)

    MANISH KUMAR

    2012-12-01

    Full Text Available A series of transition metal complexes of the ligand 5-bromo salicylaldehyde-2-furoic acid hydrazide have been prepared using Ti(III, Mn(III, V(III, Co(III, Fe(III, Ru(III and Rh(III. The complexes have been characterized by elemental analyses, melting points, molar conductance, magnetic susceptibility measurement, electronic and infra red spectral studies. Based on these studies octahedral structures have been proposed for these complexes. The ligand has behaved in dibasic tridentate manner. The I.R. spectra of the complexes revealed non-participation of furan ring oxygen in coordination with the metal ions.

  5. Synthesis, characterisation and biological evaluation of copper and silver complexes based on acetylsalicylic acid.

    Science.gov (United States)

    Rubner, Gerhard; Bensdorf, Kerstin; Wellner, Anja; Bergemann, Silke; Gust, Ronald

    2011-10-01

    Metalcarbonyl complexes with ligands derived from acetylsalicylic acid demonstrated high cytotoxic potential against various tumor cell lines and strong inhibition of the cyclooxygenase enzymes COX-1 and 2. In this study we tried to achieve comparable effects with [alkyne]silver or copper trifluoromethanesulfonate complexes which are more hydrophilic then the uncharged metalcarbonyl derivatives. All compounds were evaluated for growth inhibition against breast (MCF-7, MDA-MB 231) and colon cancer (HT-29) cell lines and for COX-1 and COX-2 inhibitory effects at isolated isoenzymes. Pure ligands showed neither cytotoxic nor COX-inhibitory effects. While the silver complexes of (but-2-ynyl)-2-acetoxybenzoate (But-ASS-Ag) and (but-2-yne-1,4-diyl)-bis(2-acetoxybenzoate) (Di-ASS-But-Ag) were strong cytostatics, only the copper complex Di-ASS-But-Cu was active. At the COX enzymes the complexes were more effective than their ligands and aspirin.

  6. Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin (IV) Halides, Organotin (IV) Halides and Thicyanates*

    OpenAIRE

    R.C. Aggarwal; D.S.S. Vara Prasada Rao

    1981-01-01

    Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS)/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH), nicotinic acid hydrazide (NH) or isonicotinic acide hydrazide (INH), x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV a...

  7. Lanthanide(III and Yttrium(III Complexes of Benzimidazole-2-Acetic Acid: Synthesis, Characterisation and Effect of La(III Complex on Germination of Wheat

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The synthesis and characterisation of lanthanide(III and yttrium(III nitrate complexes of benzimidazole-2-acetic acid (HBIA are reported. The complexes have been characterised by elemental analysis, molar conductance, magnetic studies, IR, 1 H NMR, UV-visible, EPR, and TG/DTA studies. They have the stoichiometry [ Ln 3 ( BIA 2 ( NO 3 7 ( H 2 O 4 ]⋅3 H 2 O where Ln=La(III, Pr(III, Nd(II, Sm(III, Eu(III, Gd(III, Tb(III, Dy(III, and Y(III. The effect of La(III complex on germination, coleoptile, and root length of two local varieties of wheat DWR-195 and GW-349 for different treatment periods has been investigated. The complex was found to exhibit enhanced activity, compared to HBIA or metal salt alone at lower treatment periods.

  8. Applied synthesis and characterisation of nanoparticles

    OpenAIRE

    Bear, J C

    2014-01-01

    This thesis covers three areas of development of nanomaterials synthesis; namely the synthesis of superhydrophobic polymer-nanoparticle composites (chapter 3), the synthesis of doped quantum dots for catalysis and photoluminescence enhancement (chapter 4) and the synthesis of magnetic iron oxide nanoparticles from inexpensive, readily available reagents (chapter 5). Details of characterisation and analytical techniques and synthetic methods used are given in chapter 2, and the thesis summaris...

  9. Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin (IV Halides, Organotin (IV Halides and Thicyanates*

    Directory of Open Access Journals (Sweden)

    R. C. Aggarwal

    1981-04-01

    Full Text Available Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH, nicotinic acid hydrazide (NH or isonicotinic acide hydrazide (INH, x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV and IR spectral studies show that NH and INH coordiante through carbonyl oxygen and terminal nitrogen; and (PH through carbonyl oxygen and ring nitrogen in monoadducts. All the three isometric pyridine carboxylic acid hydrazides are coordinated through pyridine nitrogen alone in the di-adducts. Octahedral geometry has been proposed for mono-as well as di-adducts.

  10. Synthesis and Characterisation of Nanomaterials

    Directory of Open Access Journals (Sweden)

    P. Saravanan

    2008-07-01

    Full Text Available Development of synthesis protocols for realising nanomaterials over a range of sizes, shapes,and chemical compositions is an important aspect of nanotechnology. The remarkable size-dependent physico-chemical properties of nanoparticles have fascinated and inspired researchactivity in this direction. This paper describes some aspects on synthesis and characterisationof nanoparticles of metals, metal alloys, and oxides, either in the form of thin films or bulk shapes.A brief discussion on processing of two-phase nanocomposite magnets is also presented.Defence Science Journal, 2008, 58(4, pp.504-516, DOI:http://dx.doi.org/10.14429/dsj.58.1671

  11. Synthesis and Characterisation of Diaryl Furoxans

    Directory of Open Access Journals (Sweden)

    V. N. Krishnamurthy

    2006-10-01

    Full Text Available The paper discusses the synthesis, characterisation, and performance evaluation of diarylfuroxans namely, bis-phenyl-3,4-furoxan (5 and bis-(4’-nitrophenyl-3,4-furoxan (6. Themolecules have been synthesised on the lines of reported method by cyclodimerisation of thenitrile oxides generated from benzaldoxime and p-nitro benzaldoxime, respectively. The synthesisedfuroxans (5 and (6 were characterised by the elemental analysis, UV, IR, and 1H NMRspectroscopy. The hazard characteristics (impact and friction sensitivity confirm that thecompounds are safe to handle. The oxygen balance, velocity of detonation and detonationpressure have been computed. The detonation velocity and pressure along with oxygen balanceincreased with the substitution of nitro group in the benzene ring, as expected. Thethermogravimetric studies on promising compound (6 brings out that maximum weight lossoccurs at decomposition temperature of 259–260 °C.

  12. Synthesis and characterisation of mucoadhesive thiolated polyallylamine.

    Science.gov (United States)

    Duggan, Sarah; Hughes, Helen; Owens, Eleanor; Duggan, Elaine; Cummins, Wayne; O' Donovan, Orla

    2016-02-29

    The thiolation of polyallylamine (PAAm) for use in mucoadhesive drug delivery has been achieved. PAAm was reacted with different ratios of Traut's reagent, yielding products with thiol contents ranging from 134-487μmol/g. Full mucoadhesive characterisation of the thiolated PAAm samples was conducted using swelling studies, mucoadhesive testing on porcine intestinal tissue and rheology. Both swelling and cohesive properties of the thiolated PAAm products were vastly improved in comparison to an unmodified PAAm control. The swelling abilities of the thiolated samples were high and the degree of thiolation of the products affected the initial rate of swelling. High levels of mucoadhesion were demonstrated by the thiolated PAAm samples, with adhesion times of greater than 24h measured for all three samples and, thus, thiol content did not appear to influence mucoadhesion. Rheological studies of the thiolated PAAm samples showed an increase in G' and G″ values upon the addition of a mucin solution which was not observed in the unmodified control, again highlighting the mucoadhesive interactions between these thiolated polymers and mucin. The synthesis of thiolated PAAm by reaction with Traut's reagent and resulting mucoadhesive properties demonstrates its potential for use a mucoadhesive drug delivery device.

  13. Synthesis, characterisation and antimicrobial activity of (5-bromo-5-nitro-2-oxido-1,3,2-dioxaphosphinan-2-yl amino acid esters

    Directory of Open Access Journals (Sweden)

    CIRANDUR SURESH REDDY

    2011-05-01

    Full Text Available Synthesis of a new series of (5-bromo-5-nitro-2-oxido-1,3,2-dioxaphosphinan-2-ylamino acid esters (3a–l was accomplished via a two step process, which involves the prior preparation of the monochloride intermediate (2 and its subsequent reaction with the amino acid esters in dry tetrahydrofuran in the presence of triethylamine at reflux temperature. The title compounds (3a–l structures were established by analytical, IR, 1H-, 13C- and 31P-NMR, and mass spectral data. They exhibited significant antibacterial and antifungal activity.

  14. The synthesis and characterisation of coordination and hydrogen-bonded networks based on 4-(3,5-dimethyl-1H-pyrazol-4-yl)benzoic acid.

    Science.gov (United States)

    Bryant, Macguire R; Burrows, Andrew D; Fitchett, Christopher M; Hawes, Chris S; Hunter, Sally O; Keenan, Luke L; Kelly, David J; Kruger, Paul E; Mahon, Mary F; Richardson, Christopher

    2015-05-21

    The synthesis, structural and thermal characterisation of a number of coordination complexes featuring the N,O-heteroditopic ligand 4-(3,5-dimethyl-1H-pyrazol-4-yl)benzoate, HL are reported. The reaction of H2L with cobalt(II) and nickel(II) nitrates at room temperature in basic DMF/H2O solution gave discrete mononuclear coordination complexes with the general formula {[M(HL)2(H2O)4]·2DMF} (M = Co (1), Ni (2)), whereas the reaction with zinc(II) nitrate gave [Zn(HL)2]∞, 3, a coordination polymer with distorted diamondoid topology and fourfold interpenetration. Coordination about the tetrahedral Zn(II) nodes in 3 are furnished by two pyrazolyl nitrogen atoms and two carboxylate oxygen atoms to give a mixed N2O2 donor set. Isotopological coordination polymers of zinc(II), {[Zn(HL)2]·2CH3OH·H2O}∞, 4, and cobalt(II), [Co(HL)2]∞, 5, are formed when the reactions are carried out under solvothermal conditions in methanol (80 °C) and water (180 °C), respectively. The reaction of H2L with cadmium(II) nitrate at room temperature in methanol gives {[Cd(HL)2(MeOH)2]·1.8MeOH}∞6, a 2-D (4,4)-connected coordination polymer, whereas with copper(II) the formation of green crystals that transform into purple crystals is observed. The metastable green phase [Cu3(HL)4(μ2-SO4)(H2O)3]∞, 7, crystallises with conserved binding domains of the heteroditopic ligand and contains two different metal nodes: a dicopper carboxylate paddle wheel motif, and, a dicopper unit bridged by sulfate ions and coordinated by ligand pyrazolyl nitrogen atoms. The resultant purple phase {[Cu(HL)2]·4CH3OH·H2O}∞, 8, however, has single copper ion nodes coordinated by mixed N2O2 donor sets with trans-square planar geometry and is threefold interpenetrated. The desolvation of 8 was followed by powder X-ray diffraction and single crystal X-ray diffraction which show desolvation induces the transition to a more closely packed structure while the coordination geometry about the copper ions and

  15. Synthesis and characterisation of uniform bisester tetra-amide segments

    NARCIS (Netherlands)

    Krijgsman, J.; Husken, D.; Gaymans, R.J.

    2003-01-01

    The synthesis and characterisation of a new type of high melting and fast crystallising amide units that can be used for copolymerisation have been studied. These bisester tetra-amide or TxTxT-dimethyl segments (T is a terephthalic unit and x=(CH2)n (n=2–8)) can be synthesised in a two-step reaction

  16. Synthesis and Characterisation of Aluminophosphate Molecular Sieves

    Energy Technology Data Exchange (ETDEWEB)

    Halvorsen, E.N.

    1996-02-01

    Catalysts are very important in petrochemical processes. One of the properties that make crystalline, microporous materials attractive for catalytic purposes is their well-defined structure and ability to act as shape selective catalysts. This doctoral thesis presents the synthesis and characterization of a number of crystalline, microporous aluminophosphates and silicoaluminophosphates. 99 refs., 50 figs., 12 tabs.

  17. Molecularly imprinted polymers: synthesis and characterisation.

    Science.gov (United States)

    Cormack, Peter A G; Elorza, Amaia Zurutuza

    2004-05-01

    This short review aims to present, in clear English, a summary of the principal synthetic considerations pertaining to good practice in the polymerisation aspects of molecular imprinting, and is primarily aimed at researchers familiar with molecular imprinting methods but with little or no prior experience in polymer synthesis. It is our hope that this will facilitate researchers to plan their own syntheses of molecular imprints in a more logical and structured fashion, and to begin to appreciate the limitations of the present synthetic approaches in this molecularly complex area, as well as the scope for rationally designing improved imprinted materials in the future.

  18. Synthesis and characterisation of technetium-99m labelled ciprofloxacin (Infecton)

    International Nuclear Information System (INIS)

    Full text: Infecton is Tc-99m labelled Ciprofloxacin, which is a synthetic carboxyquinolone derivative with broad-spectrum antimicrobial activity. It is a new class of radiopharmaceutical designed for imaging live bacterial infection. Conventional imaging agents such as Tc-99m or In-111 labelled leucocytes are either time-consuming or hazardous due to blood handling. These can be obviated by the use of Infecton which we synthesised by modifying the procedure described by Britton and co-workers (Lancet 1996;..347: 233-235). Bioassay and animal studies have been performed with a view to its use in infection imaging in patients. The first task was to prepare pure ciprofloxacin from its commercially available lactate salt. This was achieved by isoelectric precipitation at pH 8.6 by adding sodium hydroxide to the formulation. The resultant precipitate was washed with 200 mL of water for injection and filtered through a cintered-glass filtering unit. The precipitate was free of lactate and sodium as analysed by Biochem analyser. The UV spectrophotometric analysis showed an absorption peak at 276.3 nm which is close to the theoretical value of 277 nm, thus confirming the purity of the compound. Infecton was synthesised by adding 2 mg of pure ciprofloxacin, 0.4 mg of formimidine sulfinic acid ( non-stannous reducing agent) and 1.0 GBq Tc-99m pertechnetate in a final volume of 1.0 mL saline into a sterile N2-filled Amersham vial and boiling the mixture at 100 deg C for 10 min. The purity of the product was 40-45%. It was passed through a DEAE Sephadex A-25 column and eluted with phosphate buffered saline (0.01M, pH 6.9) with a purity of >96%. The preparation was characterised by bioassay (n=3) by adding Infecton to four different broths of bacterial strains viz Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and MRSA with resultant binding of 50.4, 45.6, 48.5 and 50.3% respectively. The binding was less than 1.0% when either ciprofloxacin or

  19. Synthesis and characterisation of technetium-99m labelled ciprofloxacin (Infecton)

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.; Choong, K.K.L.; Olma, T.R.; Mieczkowski, S. [Westmead and the New Childrens Hospital, Westmead, NSW (Australia). Department of Nuclear Medicineand Ultrasound and Centre for infectious Diseases and Microbiology laboratory Services

    1998-06-01

    Full text: Infecton is Tc-99m labelled Ciprofloxacin, which is a synthetic carboxyquinolone derivative with broad-spectrum antimicrobial activity. It is a new class of radiopharmaceutical designed for imaging live bacterial infection. Conventional imaging agents such as Tc-99m or In-111 labelled leucocytes are either time-consuming or hazardous due to blood handling. These can be obviated by the use of Infecton which we synthesised by modifying the procedure described by Britton and co-workers (Lancet 1996;..347: 233-235). Bioassay and animal studies have been performed with a view to its use in infection imaging in patients. The first task was to prepare pure ciprofloxacin from its commercially available lactate salt. This was achieved by isoelectric precipitation at pH 8.6 by adding sodium hydroxide to the formulation. The resultant precipitate was washed with 200 mL of water for injection and filtered through a cintered-glass filtering unit. The precipitate was free of lactate and sodium as analysed by Biochem analyser. The UV spectrophotometric analysis showed an absorption peak at 276.3 nm which is close to the theoretical value of 277 nm, thus confirming the purity of the compound. Infecton was synthesised by adding 2 mg of pure ciprofloxacin, 0.4 mg of formimidine sulfinic acid ( non-stannous reducing agent) and 1.0 GBq Tc-99m pertechnetate in a final volume of 1.0 mL saline into a sterile N{sub 2}-filled Amersham vial and boiling the mixture at 100 deg C for 10 min. The purity of the product was 40-45%. It was passed through a DEAE Sephadex A-25 column and eluted with phosphate buffered saline (0.01M, pH 6.9) with a purity of >96%. The preparation was characterised by bioassay (n=3) by adding Infecton to four different broths of bacterial strains viz Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and MRSA with resultant binding of 50.4, 45.6, 48.5 and 50.3% respectively. The binding was less than 1.0% when either ciprofloxacin or

  20. Synthesis, characterisation of polyaniline-Fe3O4 magnetic nanocomposite and its application for removal of an acid violet 19 dye

    Science.gov (United States)

    Patil, Manohar R.; Khairnar, Subhash D.; Shrivastava, V. S.

    2016-04-01

    The present work deals with the development of a new method for the removal of dyes from an aqueous solution using polyaniline (PANI)-Fe3O4 magnetic nanocomposite. It is synthesised in situ through self-polymerisation of monomer aniline. Photocatalytic degradation studies were carried out for cationic acid violet 19 (acid fuchsine) dye using PANI-Fe3O4 nanocomposite in aqueous solution. Different parameters like catalyst dose, contact time and pH have been studied to optimise reaction condition. The optimum conditions for the removal of the dye are initial concentration 20 mg/l, adsorbent dose 6 gm/l, pH 7. The EDS technique gives elemental composition of synthesised PANI-Fe3O4. The SEM and XRD studies were carried for morphological feature characteristics of PANI-Fe3O4 nanocomposite. The VSM (vibrating sample magnetometer) gives magnetic property of PANI-Fe3O4 nanocomposite; also FT-IR analysis gives characteristics frequency of synthesised PANI-Fe3O4. Besides the above studies kinetic study has also been carried out.

  1. Electrochemical synthesis, characterisation and phytogenic properties of silver nanoparticles

    Science.gov (United States)

    Singaravelan, R.; Bangaru Sudarsan Alwar, S.

    2015-11-01

    This work exemplifies a simple and rapid method for the synthesis of silver nanodendrite with a novel electrochemical technique. The antibacterial activity of these silver nanoparticles (Ag NPs) against pathogenic bacteria was investigated along with the routine study of optical and spectral characterisation. The optical properties of the silver nanoparticles were characterised by diffuse reflectance spectroscopy. The optical band gap energy of the electrodeposited Ag NPs was determined from the diffuse reflectance using Kubelka-Munk formula. X-ray diffraction (XRD) studies were carried out to determine the crystalline nature of the silver nanoparticles which confirmed the formation of silver nanocrystals. The XRD pattern revealed that the electrodeposited Ag NPs were in the cubic geometry with dendrite preponderance. The average particle size and the peak broadening were deliberated using Debye-Scherrer equation and lattice strain due to the peak broadening was studied using Williamson-Hall method. Surface morphology of the Ag NPs was characterised by high-resolution scanning electron microscope and the results showed the high degree of aggregation in the particles. The antibacterial activity of the Ag NPs was evaluated and showed unprecedented level antibacterial activity against multidrug resistant strains such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia and Escherichia coli in combination with Streptomycin.

  2. Synthesis, characterisation and microbial utilisation of amorphous polysugars from lactose.

    Science.gov (United States)

    Daines, Alison M; Smart, Zlatka; Sims, Ian M; Tannock, Gerald W; Hinkley, Simon F R

    2015-03-01

    The melt polymerisations of glucose, galactose, xylose and fucose with citric acid, and mixtures of sugars therein are reported. Characterisation of the citric-acid catalysed reaction products indicated similar degrees of branched polymerisation but differences in the overall molecular weight of the polymers produced. The dairy by-product lactose could not be polymerised in a similar fashion but was shown to be readily hydrolysed using microwave radiation and a polymer generated from the melt condensation of the resultant glucose and galactose monosaccharides. A preliminary assessment of the bifido-bacterial utilisation of the lactose-derived polymerised products demonstrated a significantly different growth profile compared to commercially utilised galactooligosaccharides (GOS). PMID:25498629

  3. Synthesis and characterisation of layered magnetic oxalato-salts

    CERN Document Server

    Watts, I D

    2000-01-01

    investigated. The local magnetic properties of (n-C sub 4 H sub 9) sub 4 NFeFe(C sub 2 O sub 4) sub 3 and PPh sub 4 MnFe(C sub 2 O sub 4) sub 3 have been probed by muon spin relaxation. The magnetic structure of deuterated examples of PPh sub 4 MnFe(C sub 2 O sub 4) sub 3 and PPh sub 4 FeFe(C sub 2 O sub 4) sub 3 has been studied by polarised neutron diffraction. The temperature-dependence of the two- dimensional magnetic correlation length has been determined by fitting these data to a Warren peak shape function. This thesis describes the synthesis and characterisation of magnetic oxalato-salts of general formula AM sup I sup I M sup I sup I sup I (C sub 2 O sub 4) sub 3 , where A is a monovalent organic cation and M sup I sup I and M sup I sup I sup I are transition metals. Compounds of this type crystallise as honeycomb layers of metal-oxalate sheets interleaved by layers of the cation and may be considered quasi two-dimensional molecular-based magnets. The compounds considered are derived from Fe sup I su...

  4. Kojic acid in organic synthesis

    OpenAIRE

    ZIRAK, MARYAM; Eftekhari-Sis, Bagher

    2015-01-01

    The reactions of kojic acid in organic synthesis are reviewed. The aim of this review is to cover the literature up to the end of 2014, showing the distribution of publications involving kojic acid chemistry in the synthesis of various pyrone containing compounds, pyridine and pyridone heterocycles, and also other organic compounds. First, introductory text about the preparation, biological, and industrial applications, and the chemical properties of kojic acid is given. Then its uses in orga...

  5. The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata).

    Science.gov (United States)

    Kuah, Meng-Kiat; Jaya-Ram, Annette; Shu-Chien, Alexander Chong

    2015-03-01

    The endogenous production of long-chain polyunsaturated fatty acids (LC-PUFA) in carnivorous teleost species inhabiting freshwater environments is poorly understood. Although a predatory lifestyle could potentially supply sufficient LC-PUFA to satisfy the requirements of these species, the nutrient-poor characteristics of the freshwater food web could impede this advantage. In this study, we report the cloning and functional characterisation of an elongase enzyme in the LC-PUFA biosynthesis pathway from striped snakehead (Channa striata), which is a strict freshwater piscivore that shows high deposition of LC-PUFA in its flesh. We also functionally characterised a previously isolated fatty acyl desaturase cDNA from this species. Results showed that the striped snakehead desaturase is capable of Δ4 and Δ5 desaturation activities, while the elongase showed the characteristics of Elovl5 elongases. Collectively, these findings reveal that striped snakehead exhibits the genetic resources to synthesise docosahexaenoic acid (DHA; 22:6n-3) from eicosapentaenoic acid (EPA; 20:5n-3). Both genes are expressed at considerable levels in the brain and the liver. In liver, both genes were up-regulated by dietary C18 PUFA, although this increase did not correspond to a significant rise in the deposition of muscle LC-PUFA. Brain tissue of fish fed with plant oil diets showed higher expression of fads2 gene compared to fish fed with fish oil-based diet, which could ensure DHA levels remain constant under limited dietary DHA intake. This suggests the importance of DHA production from EPA via the ∆4 desaturation step in order to maintain an optimal reserve of DHA in the neuronal tissues of carnivores.

  6. The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata).

    Science.gov (United States)

    Kuah, Meng-Kiat; Jaya-Ram, Annette; Shu-Chien, Alexander Chong

    2015-03-01

    The endogenous production of long-chain polyunsaturated fatty acids (LC-PUFA) in carnivorous teleost species inhabiting freshwater environments is poorly understood. Although a predatory lifestyle could potentially supply sufficient LC-PUFA to satisfy the requirements of these species, the nutrient-poor characteristics of the freshwater food web could impede this advantage. In this study, we report the cloning and functional characterisation of an elongase enzyme in the LC-PUFA biosynthesis pathway from striped snakehead (Channa striata), which is a strict freshwater piscivore that shows high deposition of LC-PUFA in its flesh. We also functionally characterised a previously isolated fatty acyl desaturase cDNA from this species. Results showed that the striped snakehead desaturase is capable of Δ4 and Δ5 desaturation activities, while the elongase showed the characteristics of Elovl5 elongases. Collectively, these findings reveal that striped snakehead exhibits the genetic resources to synthesise docosahexaenoic acid (DHA; 22:6n-3) from eicosapentaenoic acid (EPA; 20:5n-3). Both genes are expressed at considerable levels in the brain and the liver. In liver, both genes were up-regulated by dietary C18 PUFA, although this increase did not correspond to a significant rise in the deposition of muscle LC-PUFA. Brain tissue of fish fed with plant oil diets showed higher expression of fads2 gene compared to fish fed with fish oil-based diet, which could ensure DHA levels remain constant under limited dietary DHA intake. This suggests the importance of DHA production from EPA via the ∆4 desaturation step in order to maintain an optimal reserve of DHA in the neuronal tissues of carnivores. PMID:25542509

  7. Ruthenium (II) polypyridyl complexes as models for artificial photosynthesis: synthesis and characterisation

    OpenAIRE

    Killeen, Jonathan Scott

    2001-01-01

    This thesis presents a study on the synthesis and characterisation of a series of novel ruthenium (II) polypyridyl complexes, which are potentially models for artificial photosynthesis. Chapter 1, the introduction, highlights the literature relevant to the topic. In Chapter 2, the experimental conditions of the various methods of characterisation are described. The synthesis and characterisation of a range of novel 5-phenyI-3-(2- pyridyl)-1,2,4-triazoles, their Ru(bpy)2 and their Ru(dg-bp...

  8. Chemical characterisation and application of acid whey in fermented milk.

    Science.gov (United States)

    Lievore, Paolla; Simões, Deise R S; Silva, Karolline M; Drunkler, Northon L; Barana, Ana C; Nogueira, Alessandro; Demiate, Ivo M

    2015-04-01

    Acid whey is a by-product from cheese processing that can be employed in beverage formulations due to its high nutritional quality. The objective of the present work was to study the physicochemical characterisation of acid whey from Petit Suisse-type cheese production and use this by-product in the formulation of fermented milk, substituting water. In addition, a reduction in the fermentation period was tested. Both the final product and the acid whey were analysed considering physicochemical determinations, and the fermented milk was evaluated by means of sensory analysis, including multiple comparison and acceptance tests, as well as purchase intention. The results of the physicochemical analyses showed that whey which was produced during both winter and summer presented higher values of protein (1.22 and 0.97 %, w/v, respectively), but there were no differences in lactose content. During the autumn, the highest solid extract was found in whey (6.00 %, w/v), with larger amounts of lactose (4.73 %, w/v) and ash (0.83 %, w/v). When analysing the fermented milk produced with added acid whey, the acceptance test resulted in 90 % of acceptance; the purchase intention showed that 54 % of the consumers would 'certainly buy' and 38 % would 'probably buy' the product. Using acid whey in a fermented milk formulation was technically viable, allowing by-product value aggregation, avoiding discharge, lowering water consumption and shortening the fermentation period. PMID:25829588

  9. Sol-gel Synthesis and Characterisation of NanocrystallineYttrium Aluminum Garnet Nanopowder

    Directory of Open Access Journals (Sweden)

    Kiranmala Devi

    2008-07-01

    Full Text Available The synthesis of  yttrium aluminum garnet (YAG (Y3 Al5O12 nanopowder was carried outby sol-gel method. Y(NO33.6H2O, Al(NO33.9H2O in the presence of citric acid as complexing agent were used as starting materials. YAG nanopowder was characterised by FTIR, TGA, andXRD. To get phase-pure nanocrystalline YAG powder at relatively lower temperature, calcinationat various temperatures was studied and calcination temperature was optimised. Particle size,estimated by XRD using Scherrer's equation, was found to be 28Œ35 nm which was further confirmed by transmission electron microscopy. The particle morphology was studied by SEM.Defence Science Journal, 2008, 58(4, pp.545-549, DOI:http://dx.doi.org/10.14429/dsj.58.1675

  10. The role of acid in the formation of hydrogen-bonded networks featuring 4,4'-dicarboxy-2,2'-bipyridine (H2dcbp): Synthesis, structural and magnetic characterisation of {[Cu(H2dcbp)Cl2].H2O}2 and [Cu(H2dcbp)(NO3)2(H2O)

    OpenAIRE

    Tynan, Eithne; Jensen, Paul; Lees, Anthea C.; Moubaraki, Boujemaa; Murray, Keith S.; Kruger, Paul E.

    2005-01-01

    Reported herein are the synthesis, structural and magnetic characterisation of two hydrogen-bonded networks featuring the 4,4?-dicarboxy-2,2?-bipyridine (H2dcbp) ligand: {[Cu(H2dcbp)(Cl)2]·H2O}2 1 and [Cu(H2dcbp)(NO3)2(H2O)] 2. Compounds 1 and 2 result from the reaction of CuCl2 and Cu(NO3)2, respectively, with H2dcbp under hydrothermal conditions in the presence of either HCl or HNO3. The acid ensures that H2dcbp remains protonated and provides the anions required for charge balance irrespec...

  11. Isolation and characterisation of lactic acid bacteria from donkey milk.

    Science.gov (United States)

    Soto Del Rio, Maria de Los Dolores; Andrighetto, Christian; Dalmasso, Alessandra; Lombardi, Angiolella; Civera, Tiziana; Bottero, Maria Teresa

    2016-08-01

    During the last years the interest in donkey milk has increased significantly mainly because of its compelling functional elements. Even if the composition and nutritional properties of donkey milk are known, its microbiota is less studied. This Research Communication aimed to provide a comprehensive characterisation of the lactic acid bacteria in raw donkey milk. RAPD-PCR assay combined with 16S rDNA sequencing analysis were used to describe the microbial diversity of several donkey farms in the North West part of Italy. The more frequently detected species were: Lactobacillus paracasei, Lactococcus lactis and Carnobacterium maltaromaticum. Less abundant genera were Leuconostoc, Enterococcus and Streptococcus. The yeast Kluyveromyces marxianus was also isolated. The bacterial and biotype distribution notably diverged among the farms. Several of the found species, not previously detected in donkey milk, could have an important probiotic activity and biotechnological potential. This study represents an important insight to the ample diversity of the microorganisms present in the highly selective ecosystem of raw donkey milk. PMID:27600975

  12. Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2015-01-01

    Full Text Available A novel cellulose-chitosan gel was successfully prepared in three steps: (1 ferrocene- (Fc- cellulose with degrees of substitution (DS of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl; (2 the β-cyclodextrin (β-CD groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3 thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose and β-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and the β-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose and β-CD-chitosan was characterised by 13C-NMR spectroscopy. The gel based on β-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid. The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.

  13. Hexanitrohexaazaisowurtzitane or CL-20 in India: Synthesis and Characterisation

    OpenAIRE

    A. K. Sider; Nirmala Sikder; B. R. Gandhe; J. P. Agrawal; Haridwar Singh

    2002-01-01

    Hexanitrohexaazaisowurtzitane (HNIW) more commonly called CL-20, the highest density and the most powerful real world explosive, has been made with very high yield and a high product purity. CL-20 is thoroughly characterised by spectral data (IR, NMR and mass) along with electron spectroscopy for chemical analysis (ESCA) and X-ray diffractogram. Furthermore, small-scale sensitivity tests have also been carried out.

  14. Synthesis and Spectroscopic Characterisation of N-Alkyl Quaternary Ammonium Salts Typical Precursors of Cyanines

    Directory of Open Access Journals (Sweden)

    P. Almeida

    2002-03-01

    Full Text Available The synthesis and spectroscopic characterisation of some representative N-alkylsubstituted quaternary ammonium salts derived from benzothiazole, benzoxazole, benzoselenazole, indole and quinoline are described. These heterocyclic salts, bearing an activated methyl group in the 2-position in relation to the nitrogen atom and N-methyl, -pentyl, -hexyl and -decyl chains, are typical precursors of cyanine dyes.

  15. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures...... and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones...

  16. Synthesis and characterisation of cationically modified phospholipid polymers.

    Science.gov (United States)

    Lewis, Andrew L; Berwick, James; Davies, Martyn C; Roberts, Clive J; Wang, Jin-Hai; Small, Sharon; Dunn, Anthony; O'Byrne, Vincent; Redman, Richard P; Jones, Stephen A

    2004-07-01

    Phospholipid-like copolymers based on 2-(methacryloyloxyethyl) phosphorylcholine were synthesised using monomer-starved free radical polymerisation methods and incorporating cationic charge in the form of the choline methacrylate monomer in amounts varying from 0 to 30 wt%, together with a 5 wt% silyl cross-linking agent in order to render them water-insoluble once thermally cured. Characterisation using a variety of techniques including nuclear magnetic resonance spectroscopy, high-pressure liquid chromatography and gel permeation chromatography showed the cationic monomer did not interfere with the polymerisation and that the desired amount of charge had been incorporated. Gravimetric and differential scanning calorimetry methods were used to evaluate the water contents of polymer membranes cured at 70 degrees C, which was seen to increase with increasing cation content, producing materials with water contents ranging from 50% to 98%. Surface plasmon resonance indicated that the coatings swelled rapidly in water, the rate and extent of swelling increasing with increasing cation level. Dynamic contact angle showed that coatings of all the polymers possessed a hydrophobic surface when dry in air, characteristic of the alkyl chains expressed at the surface (>100 degrees advancing angle). Rearrangement of the hydrophilic groups to the surface occurred once wet, to produce highly wettable surfaces with a decrease in advancing angle with increasing cation content. Atomic force microscopy showed all polymer films to be smooth with no features in topographical or phase imaging. Mechanical properties of the dry films were also unaffected by the increase in cation content.

  17. Synthesis and characterisation: Zinc oxide-sulfide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prinsa, E-mail: prinsa.verma@gmail.co [Nanophosphor Application Center, Allahabad University (India); Satish Dhawan Space Center, ISRO (India); Pandey, Avinash C. [Nanophosphor Application Center, Allahabad University (India); Bhargava, R.N. [Nanocrystal Technology, New York (United States)

    2009-11-15

    A novel synthesis method is presented for the preparation of nanosized-semiconductor zinc oxide-sulphide (ZnO/ZnS) core-shell nanocomposites, both formed sequentially from a single-source solid precursor. ZnO nanocrystals were synthesized by a simple co-precipitation method and ZnO/ZnS core-shell nanocomposites were successfully fabricated by sulfidation of ZnO nanocrystals via a facile chemical synthesis at room temperature. The as-obtained samples were characterized by X-ray diffraction and transmission electron microscopy. The results showed that the pure ZnO nanocrystals were hexagonal wurtzite crystal structures and the ZnS nanoparticles were sphalerite structure with the size of about 10 nm grown on the surface of the ZnO nanocrystals. Optical properties measured reveal that ZnO/ZnS core-shell nanocomposites have integrated the photoluminescent effect of ZnO and ZnS. Based on the results of the experiments, a possible formation mechanism of ZnO/ZnS core-shell nanocomposites was also suggested. This treatment is suggested to improve various properties of optoelectronically valuable ZnO/ZnS nanocomposites. These nanosized semiconductor nanocomposites can form a new class of luminescent materials for various applications.

  18. Synthesis and characterisation of new spin crossover salts and molecular magnets.

    OpenAIRE

    Daniell, Joanna

    2016-01-01

    This research focuses on the synthesis and characterisation of novel molecular salts with the potential to undergo spin crossover (SCO) transitions. SCO describes the reversible transition between the LS and HS states, which can occur in some first row transition metal complexes with d4 – d7 valence electrons, induced by changes in external stimuli such as temperature. The rearrangement of electrons during the SCO transition results in changes to the properties exhibited by the bulk material,...

  19. Synthesis, characterisation, electrical and optical properties of copper borate compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kipcak, Azmi Seyhun; Senberber, Fatma Tugce [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Istanbul (Turkey); Aydin Yuksel, Sureyya [Department of Physics, Faculty of Arts and Science, Yildiz Technical University, Istanbul (Turkey); Derun, Emek Moroydor, E-mail: moroydor@gmail.com [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Istanbul (Turkey); Piskin, Sabriye [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Istanbul (Turkey)

    2015-10-15

    Highlights: • Cu(BO{sub 2}){sub 2} was synthesized at the form of with pdf number of “00-001-0472”. • Particle sizes were found between 162.72 and 56.44 nm and 195.76 and 75.73 nm at CuSNaH. • Reaction yields were 90.4 ± 0.84, 96.9 ± 0.78 and 78.9 ± 0.76% for CuST, CuSB and CuSNaH. • The resistivity of CuST, CuSB and CuSNaH are 1.10 × 10{sup 7}, 7.02 × 10{sup 6} and 8.62 × 10{sup 5} Ωm. • The optical energy gap was 3.76 eV. - Abstract: The hydrothermal synthesis of copper borate compounds [Cu(BO{sub 2}){sub 2}] was studied, and several parameters were found to affect the synthesis. Raw materials, including CuSO{sub 4}·5H{sub 2}O, Na{sub 2}B{sub 4}O{sub 7}·5H{sub 2}O, Na{sub 2}B{sub 4}O{sub 7}·10H{sub 2}O, NaOH and H{sub 3}BO{sub 3}, were used. Reaction temperatures and reaction times between 40 °C and 100 °C and 15 and 240 min, respectively, were used. The as-synthesised copper borate was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The yields of the reactions were also calculated. Single-phase, nanoparticulate copper borate compounds (Cu(BO{sub 2}){sub 2}) possessing high XRD crystal scores were obtained; the reactions used to obtain these materials were highly efficient. Electrical resistivity and optical absorbance measurements were carried out on the compounds obtained from the highest yielding reactions. The results of this study showed that even using a reaction time of 15 min, copper borate formation was successfully achieved.

  20. Characterisation of CMP-sialic acid transporter substrate recognition

    NARCIS (Netherlands)

    Maggioni, A.; Itzstein, M. von; Guzman, I.B. Rodriguez; Ashikov, A.M.; Stephens, A.S.; Haselhorst, T.; Tiralongo, J.

    2013-01-01

    CMP-sialic acid transporter: We report an in-depth, multidisciplinary, structural study that has identified the amino acid residues intimately involved in CMP-sialic acid transporter (CST) substrate specificity. Our data provide a significant contribution towards a better understanding the structure

  1. Biobased furandicarboxylic acids (FDCAs): effects of isomeric substitution on polyester synthesis and properties

    NARCIS (Netherlands)

    Thiyagarajan, S.; Vogelzang, W.; Knoop, J.R.I.; Frissen, A.E.; Haveren, van J.; Es, van D.S.

    2014-01-01

    In this study we present the application of different isomers of furandicarboxylic acid, or FDCA, obtained from agro-residues, in polyester synthesis. New polyesters based on 2,4-FDCA and 3,4-FDCA isomers with (linear) diols were thoroughly characterised and compared with their as-synthesised 2,5-FD

  2. Characterisation of boric acid aerosol behaviour and interactions with stainless steel

    International Nuclear Information System (INIS)

    Experiments have been conducted to determine the physical characteristics of boric acid aerosol. Aqueous solutions of boric acid (either 200 or 2000 ppm boron) were injected at a controlled rate onto a 304 stainless steel cone held at 1000oC. The transport and deposition of the resulting aerosol was studied through a system including pipework and a dilution chamber. Work was also undertaken to characterise the interaction between boric acid and stainless steel. Boric acid was vaporized in steam-argon atmospheres at 300oC and passed over 304 stainless steel coupons held at temperatures between 400 and 1000oC. (author)

  3. Characterisation of boric acid aerosol behaviour and interactions with stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, A.B.; Beard, A.M.; Bennett, P.J.; Benson, C.G.

    1991-03-01

    Experiments have been conducted to determine the physical characteristics of boric acid aerosol. Aqueous solutions of boric acid (either 200 or 2000 ppm boron) were injected at a controlled rate onto a 304 stainless steel cone held at 1000{sup o}C. The transport and deposition of the resulting aerosol was studied through a system including pipework and a dilution chamber. Work was also undertaken to characterise the interaction between boric acid and stainless steel. Boric acid was vaporized in steam-argon atmospheres at 300{sup o}C and passed over 304 stainless steel coupons held at temperatures between 400 and 1000{sup o}C. (author).

  4. Preparation and characterisation of acrylamide/maleic acid hydrogel

    Directory of Open Access Journals (Sweden)

    Klinpituksa, P.

    2005-09-01

    Full Text Available Acrylamide/maleic acid hydrogel, a superabsorbent polymer, was prepared by free radical polymerization in aqueous solution of acrylamide (AAm and maleic acid (MA : monomer and comonomer, respectively. Potassium persulfate and N,N,N’,N’-tetramethylethylenediamine were used as an initiator system. Also, ethylene glycol dimethacrylate (EGDMA and N,N’-methylenebisacrylamide (MBA were used as crosslinkers. Different compositions of acrylamide, maleic acid and crosslinkers were employed. Water swelling, equilibrium water content and swelling power of the hydrogel formed were determined. The result showed that the swelling in water at equilibrium of hydrogels was in the range of 8,420-10,300% and 3,160- 3,560%, equilibrium water content was in the range of 0.9880-0.9902 and 0.9630-0.9727 and swelling power was in the range of 84-103 and 31-36 using 1%EGDMA and 1%MBA as crosslinkers, respectively. The diffusion of water into hydrogel followed non-Fickian character based on swelling power.

  5. Catalytic asymmetric synthesis of mycocerosic acid

    NARCIS (Netherlands)

    ter Horst, B.; Feringa, B.L.; J. Minnaard, A.

    2007-01-01

    The first catalytic asymmetric total synthesis of mycocerosic acid was achieved via the application of iterative enantioselective 1,4-addition reactions and allows for the efficient construction of 1,3-polymethyl arrays with full stereocontrol; further exemplified by the synthesis of tetramethyl-dec

  6. Extraction and characterisation of aqueous organic acids from natural waters

    International Nuclear Information System (INIS)

    Humic and fulvic acids were extracted from large volumes of groundwater associated with the Broubster and Needle's Eye natural analogue sites, and the BGS research site at Drigg in Cumbria. Extractions were performed by both batchwise extraction and radial flow chromatography using DEAE-cellulose. Retained humic substances were eluted using NaOH and separated into humic and fulvic components by acidification to pH 1. After separation the humic component was purified by repetitive precipitation and dissolution whilst the fulvic component was purified by absorption chromatography. The resulting humic substances were shown to be of high purity with respect to metallic elements, with less than 1% of available sites being occupied. During elution the association of trace elements with humic substances was monitored and a high degree of association between humic substances, U and the Rare Earth Elements was noted. (author)

  7. Characterising the phase behaviour of stearic acid and its triethanolamine soap and acid-soap by infrared spectroscopy.

    Science.gov (United States)

    Pudney, Paul D A; Mutch, Kevin J; Zhu, Shiping

    2009-07-01

    The behaviour of stearic acid neutralised by triethanolamine to form soap and its acid-soap has been examined by infrared spectroscopy. It was found that not only could the neutralisation behaviour be characterised, but the thermotropic behaviour could also be followed. The neutralisation confirmed the formation of a fixed stoichiometeric ratio, 2 : 1, acid-soap. When following the thermotropic behaviour the break up of the acid-soap could be followed along with various disordering and melting transitions of the alkyl chain tail. This allowed all the thermal transitions that have been observed to be characterised in terms of the type of molecular rearrangement that was occurring and also the transition temperature at which they occurred. This allowed the binary phase diagram to be plotted and understood for this system. This is the first time IR has been used to measure a whole phase diagram of this type. The nature of the acid-soap complex itself was also characterised, with very short hydrogen bonds being present as well as a free, non-hydrogen bonded, hydroxyl group.

  8. Synthesis of β-Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    Zhao Yonghua; Ma Zhihua; Jiang Nan; Wang Jianbo

    2004-01-01

    In recent years, β-amino acids and their derivatives have attracted considerable attention due to their occurrence in biologically active natural products, such as dolastatins,cyclohexylnorstatine and Taxol. β-Amino acids also find application in the synthesis of β-lactams,piperidines, indolizidines. Moreover, the peptides consisting of β-amino acids, the so-called β-peptides, have been extensively studied recently. Consequently, considerable efforts have been directed to the synthesis of β-amino acids and their derivatives1. In particular, stereoselective synthesis of β-amino acids has been a challenging project, and there are only limited methods available. In this presentation, we report our efforts in this area.

  9. Synthesis, characterisation and crystal structures of two bi-oxadiazole derivatives featuring the trifluoromethyl group.

    Science.gov (United States)

    Kettner, Marcos A; Klapötke, Thomas M; Witkowski, Tomasz G; von Hundling, Felix

    2015-03-01

    The synthesis, characterisation, and crystal structure determination of the closely related compounds 3,3'-bi-(5-trifluoromethyl-1,2,4-oxadiazole) and 5,5'-bi-(2-trifluoromethyl-1,3,4-oxadiazole) are reported. These two compounds are known for their bioactivity; however, in this study they serve as model compounds to evaluate the suitability of the heterocyclic oxadiazole ring system for energetic materials when the fluorine atoms in the exocyclic CF3 groups are substituted successively by nitro groups. Quantum chemical calculations for the bi-1,3,4-oxadiazole derivatives with difluoronitromethyl, fluorodinitromethyl, and trinitromethyl groups have been carried out and predict promising energetic performances for both explosive and propulsive applications.

  10. Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A

    International Nuclear Information System (INIS)

    When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A

  11. Synthesis of stearic acid triethanolamine ester over solid acid catalysts

    Institute of Scientific and Technical Information of China (English)

    Tao Geng; Qiu Xiao Li; Ya Jie Jiang; Wei Wang

    2010-01-01

    The synthesis of stearic acid triethanolamine ester over solid acid catalysts was investigated.The results showed that the catalytic activity and selectivity of zirconium sulfate supported on SBA-15(6)(pore diameter 6 nm)is better than that of commonly used hypophosphorous acid,zirconium sulfate supported on MCM-41 and zirconium sulfate supported on SBA-15(9)(pore diameter 9 nm).

  12. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    Science.gov (United States)

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis. PMID:27349116

  13. Low-pressure Chemical Vapour Deposition of Silicon Nanoparticles:Synthesis and Characterisation

    Directory of Open Access Journals (Sweden)

    A. Kumar

    2008-07-01

    Full Text Available emiconductor nanostructures such as quantum wells, quantum wires or quantum dots exhibit superior properties in comparison to their bulk forms. Quantum dots are described aszero-dimensional electron gas system, as carriers are confined in all the three directions. Densityof states is discrete function of energy. Allowed energy spectrum is discrete like in an atom.Energy band gap is broadened due to carriers confinement. Semiconductor quantum dots exhibittypical coulomb blockade characteristic which is exploited for development of new generationof nanoelectronic devices namely single-electron transistor, memories, etc, whose operationdepends on quantum mechanical tunneling of carriers through energy barriers. Thesesemiconductor nanostructures emit light in visible range upon excitation by optical means. Inrecent years,  research  has been focused on different nano-scale materials; metals (Au, Ag, Fe,Mn, Ni, metal oxides (SnO2, ZnO2, compound semiconductors (GaAs, GaAlAs, CdSe, CdS,GaN, and elemental semiconductors (silicon and germanium. As silicon is the most favouredmaterial in the established integrated circuits manufacturing technology, research is being donefor controlled synthesis and characterisation of Si nanoparticles. The Si nanoparticles havebeen synthesised on oxide and nitride layers over  Si substrate by IC technology compatiblelow-pressure chemical vapour deposition technique. Atomic force microscopy (AFMcharacterisation has been extensively carried out on the samples. It is shown that the tip radiusand shape of tip lead to less accurate estimate of the actual size. The AFM images have been evaluated based on the real surface topography and shape of the tip. Photolumine scence (PL studies have been performed to characterise the samples. The PL measurements showed visiblelight emission from synthesised silicon nanoparticles.Defence Science Journal, 2008, 58(4, pp.550-558, DOI:http://dx.doi.org/10.14429/dsj.58.1676

  14. Enantioselective Total Synthesis of Plectosphaeroic Acid B

    OpenAIRE

    Jabri, Salman Y.; Overman, Larry E.

    2013-01-01

    The first total synthesis of a member of the plectosphaeroic acid family of fungal natural products is reported. Key steps include the late-stage formation of the hindered N6–C9″ bond and stereoselective introduction of the two methylthio substituents.

  15. Synthesis and optical characterisation of triphenylamine-based hole extractor materials for CdSe quantum dots

    OpenAIRE

    Planells, Miquel; Reynolds, Luke X.; Bansode, Umesh; Chhatre, Shraddha; Ogale, Satishchandra; Robertson, Neil; Haque, Saif A

    2013-01-01

    We report the synthesis and optical characterisation of different triphenylamine-based hole capture materials able to anchor to CdSe quantum dots (QDs). Cyclic voltammetry studies indicate that these materials exhibit reversible electrochemical behaviour. Photoluminescence and transient absorption spectroscopy techniques are used to study interfacial charge transfer properties of the triphenylamine functionalized CdSe QDs. Specifically, we show that the functionalized QDs based on the most ea...

  16. Novel Zinc(II Complexes of Heterocyclic Ligands as Antimicrobial Agents: Synthesis, Characterisation, and Antimicrobial Studies

    Directory of Open Access Journals (Sweden)

    Ramesh S. Yamgar

    2014-01-01

    Full Text Available The synthesis and antimicrobial activity of novel Zn(II metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z-{[3-(N-methylaminopropyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E-{[4-(1H-1,2,4-triazol-1-ylmethylphenyl]imino}methyl]phenol, and (4S-4-{4-[(E-(2-hydroxybenzylideneamino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria: E. coli and Pseudomonas fluorescens, Gram positive bacteria: Staphylococcus aureus, and also against fungi, that is, C. albicans and A. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2 μg/mL. The “in vitro” data has identified [Zn(NMAPIMHMC2]·2H2O, [Zn(TMPIMP2]·2H2O, and [Zn(HBABO2]·2H2O as potential therapeutic antifungal agents against C. albicans and A. niger.

  17. Pectin functionalised by fatty acids: Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopic characterisation

    Science.gov (United States)

    Kamnev, Alexander A.; Calce, Enrica; Tarantilis, Petros A.; Tugarova, Anna V.; De Luca, Stefania

    2015-01-01

    Chemically modified pectin derivatives obtained by partial esterification of its hydroxyl moieties with fatty acids (FA; oleic, linoleic and palmitic acids), as well as the initial apple peel pectin were comparatively characterised using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Characteristic changes observed in DRIFT spectra in going from pectin to its FA esters are related to the corresponding chemical modifications. Comparing the DRIFT spectra with some reported data on FTIR spectra of the same materials measured in KBr or NaCl matrices has revealed noticeable shifts of several polar functional groups both in pectin and in its FA-esterified products induced by the halide salts. The results obtained have implications for careful structural analyses of biopolymers with hydrophilic functional groups by means of different FTIR spectroscopic methodologies.

  18. GREEN SYNTHESIS OF GOLD NANOPARTICLES USING TOONA CILIATA METHANOL BARK EXTRACT AND THEIR CHARACTERISATION

    OpenAIRE

    Kaushik Rajan; Mann Avninder Singh; Sandhu Bharpur Singh; Parihar Vidya Bhushan Singh

    2012-01-01

    In the present study, we identified and justified the use of MeOH extract from Toona ciliata bark as a reducing and capping agent for the ecofriendly synthesis of gold nanoparticles on the basis of modern analytical techniques. The reduction of 1.0 mM aqueous solution of aurochloric acid with 1 ml, 1% w/v aqueous solution of MeOH bark extract from Toona ciliata has resulted in the formation of stabilised Gold Nanoparticles (AuNPs). The synthesised gold particles showed a surface plasmon band ...

  19. Synthesis of carbon-13-labeled tetradecanoic acids.

    Science.gov (United States)

    Sparrow, J T; Patel, K M; Morrisett, J D

    1983-07-01

    The synthesis of tetradecanoic acid enriched with 13C at carbons 1, 3, or 6 is described. The label at the carbonyl carbon was introduced by treating 1-bromotridecane with K13CN (90% enriched) to form the 13C-labeled nitrile, which upon hydrolysis yielded the desired acid. The [3-13C]tetradecanoic acid was synthesized by alkylation of diethyl sodio-malonate with [1-13C]1-bromododecane; the acid was obtained upon saponification and decarboxylation. The label at the 6 position was introduced by coupling the appropriately labeled alkylcadmium chloride with the half acid chloride methyl ester of the appropriate dioic acid, giving the corresponding oxo fatty acid ester. Formation of the tosylhydrazone of the oxo-ester followed by reduction with sodium cyanoborohydride gave the labeled methyl tetradecanoate which, upon hydrolysis, yielded the desired tetradecanoic acid. All tetradecanoic acids were identical to unlabeled analogs as evaluated by gas-liquid chromatography and infrared or NMR spectroscopy. These labeled fatty acids were used subsequently to prepare the correspondingly labeled diacyl phosphatidylcholines. PMID:6631228

  20. Physical and structural characterisation of starch/polyester blends with tartaric acid

    International Nuclear Information System (INIS)

    Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. The effects of TA, glycerol and starch + PBAT on the mechanical, optical and structural properties of the films were evaluated, with formulations based in a constrained mixture design. Tartaric acid acts as a compatibiliser and promotes the acid hydrolysis of starch chains. These two functions explain the observed film resistance and opacity. TA reduced the weight loss in water. Scanning electron microscopy (SEM) images showed that TA reduces the interfacial tension between the polymeric phases, resulting in more homogeneous films. Nuclear magnetic resonance (13C CPMAS) and Fourier transform infrared spectroscopy (FT-IR) suggest that tartaric acid is able to react with the hydroxyl groups of the starch by esterification/transesterification reactions, confirming its role as a compatibiliser. The addition of TA results in materials with better properties that are suitable for use in food packaging. - Highlights: • Tartaric acid (TA) was efficient as compatibiliser of starch/PBAT blends. • Film properties were analysed based on the modelling of the mixture design. • Greater proportions of TA resulted in more opaque and less soluble materials. • Esterification reactions promoted by TA were characterised by FT-IR and 13C CPMAS NMR. • Compatibilised blends with TA showed better morphological and mechanical properties

  1. Physical and structural characterisation of starch/polyester blends with tartaric acid

    Energy Technology Data Exchange (ETDEWEB)

    Olivato, J.B., E-mail: jubonametti@uel.br [Departamento de Ciência e Tecnologia de Alimentos, Centro de Ciências Agrárias, Universidade Estadual de Londrina, PO Box 6001, 86051-980 Londrina, PR (Brazil); Müller, C.M.O. [Departamento de Ciência e Tecnologia de Alimentos, Centro de Ciências Agrárias, Universidade Estadual de Londrina, PO Box 6001, 86051-980 Londrina, PR (Brazil); Carvalho, G.M. [Departamento de Química, Centro de Ciências Exatas, Universidade Estadual de Londrina, PO Box 6001, 86051-980 Londrina, PR (Brazil); Yamashita, F.; Grossmann, M.V.E. [Departamento de Ciência e Tecnologia de Alimentos, Centro de Ciências Agrárias, Universidade Estadual de Londrina, PO Box 6001, 86051-980 Londrina, PR (Brazil)

    2014-06-01

    Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. The effects of TA, glycerol and starch + PBAT on the mechanical, optical and structural properties of the films were evaluated, with formulations based in a constrained mixture design. Tartaric acid acts as a compatibiliser and promotes the acid hydrolysis of starch chains. These two functions explain the observed film resistance and opacity. TA reduced the weight loss in water. Scanning electron microscopy (SEM) images showed that TA reduces the interfacial tension between the polymeric phases, resulting in more homogeneous films. Nuclear magnetic resonance ({sup 13}C CPMAS) and Fourier transform infrared spectroscopy (FT-IR) suggest that tartaric acid is able to react with the hydroxyl groups of the starch by esterification/transesterification reactions, confirming its role as a compatibiliser. The addition of TA results in materials with better properties that are suitable for use in food packaging. - Highlights: • Tartaric acid (TA) was efficient as compatibiliser of starch/PBAT blends. • Film properties were analysed based on the modelling of the mixture design. • Greater proportions of TA resulted in more opaque and less soluble materials. • Esterification reactions promoted by TA were characterised by FT-IR and {sup 13}C CPMAS NMR. • Compatibilised blends with TA showed better morphological and mechanical properties.

  2. Lipase catalyzed synthesis of epoxy-fatty acids

    Institute of Scientific and Technical Information of China (English)

    CHEN, Qian; LI, Zu-Yi

    2000-01-01

    Lipase catalyzed synthesis of epoxy-fatty acidas from unsaturated carboxylic acids was investigated.Under mild conditions unsaturated arboxylic acids were convcveed to peroxide,then the unsaturated peroxycarboxylic acids epoxidised the C=C bond of themselves

  3. Sol-gel synthesis and characterisation of nano-scale hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Bilton, M; Brown, A P; Milne, S J, E-mail: pre5mb@leeds.ac.u [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2010-07-01

    Hydroxyapatite (HAp) forms the main mineral component of bone and teeth. This naturally occurring HAp is in the form of nano-metre sized crystallites of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} that contain a number of cation and anion impurities, for example CO{sub 3}{sup 2-}, F{sup -}, Na{sup +}, Mg{sup 2+} and Sr{sup 2+}. Synthetic nano-sized HAp particles exhibit favourable biocompatibility and bioactivity and in order to better match the composition to natural HAp there is great interest in producing a range of chemically modified powders. In this study, two HAp powders have been synthesised via a water-based low-temperature sol-gel method and a third, commercial powder from Sigma-Aldrich have been analysed. Subsequent powder calcination has been carried out within the temperature range of 500-700 {sup 0}C and the products characterised by bulk chemical analysis, X-ray diffraction and electron microscopy. Energy dispersive X-ray spectroscopy (EDX) in the TEM has been used to assess the composition of individual HAp particles. In order to do this accurately it is first necessary to account for the sensitivity of the HAp structure and composition to irradiation by the high energy electron beam of the TEM. This was done by monitoring the estimated Ca/P ratio derived from TEM-EDX of stoichiometric HAp under increasing levels of electron fluence. A fluence threshold (at a given beam energy) was established below which the measured Ca/P ratio can be considered to be stable. Subsequent elemental analysis at or below this threshold has enabled the variation in composition between particles both within and between synthesis batches to be accurately assessed. Compositional variability between particles is also evident, even in the commercial powder, but is far greater in the powders prepared by the sol-gel method.

  4. Characterisation of a proposed internet synthesis of N,N-dimethyltryptamine using liquid chromatography/electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Martins, Cláudia P B; Freeman, Sally; Alder, John F; Brandt, Simon D

    2009-08-14

    The psychoactive properties of N,N-dimethyltryptamine (DMT) are known to induce altered states of consciousness in humans. These properties attract great interest from clinical, neuroscientific, clandestine and forensic communities. The Breath of Hope Synthesis was reported on an internet website as a convenient two-step methodology for the preparation of DMT. The analytical characterisation of the first stage was the subject of previous publications by the authors and involved the thermal decarboxylation of tryptophan and the formation of tryptamine. The present study reports on the characterisation of the second step of this procedure which was based on the methylation of tryptamine. This employed methyl iodide and benzyltriethylammonium chloride/sodium hydroxide as a phase transfer catalyst. The reaction product was characterised by liquid chromatography/electrospray ionisation tandem mass spectrometry and orthogonal acceleration time-of-flight mass spectrometry. Quantitative evaluation was carried out in positive multiple reaction monitoring mode (MRM), which included synthesis of the identified reaction products. MRM screening of the product did not lead to the detection of DMT. Instead, 11.1% tryptamine starting material, 21.0% N,N,N-trimethyltryptammonium iodide (TMT) and 47.4% 1-N-methyl-TMT were detected. A 0.5% trace of the monomethylated N-methyltryptamine was also detected. This study demonstrated the impact on product purity of doubtful synthetic methodologies discussed on the internet. PMID:19592003

  5. Development and characterisation of molecularly imprinted polymers based on methacrylic acid for selective recognition of drugs.

    Science.gov (United States)

    Shi, Xizhi; Wu, Aibo; Qu, Guorun; Li, Rongxiu; Zhang, Dabing

    2007-09-01

    Specific molecularly imprinted polymers (MIPs) for the drug reserpine (RES) using methacrylic acid (MAA) as the functional monomer were developed and characterised for the first time in this study. Evaluation of the various polymers by binding assays indicated that the optimum ratio of functional monomer to template was 4:1. Furthermore, the imprinting effect of the MIPs was assessed by the chromatographic method, which demonstrated that the MIPs had better chromatographic behavior and selectivity than those of the corresponding NIPs. A combination of BET, NMR, UV spectroscopy, and MISPE analyses for investigation of the imprinting and recognition properties revealed that strong specific interactions between the functional monomer and RES in the prepolymerization solutions and the aqueous solutions were probably responsible for RES recognition. The preparation of RES MIPs and elucidation of imprinting and recognition mechanisms may serve as useful references for other drug MIPs.

  6. Synthesis and Characterisation of Biocompatible Polymer-Conjugated Magnetic Beads for Enhancement Stability of Urease.

    Science.gov (United States)

    Doğaç, Yasemin Ispirli; Teke, Mustafa

    2016-04-01

    We reported natural polymer-conjugated magnetic featured urease systems for removal of urea effectively. The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70 °C), pH stability (4.0-9.0), operational stability (0-250 min), reusability (18 times) and storage stability (24 weeks) were studied for characterisation of the urease-encapsulated biocompatible polymer-conjugated magnetic beads. Also, the surface groups and chemical structure of the magnetic beads were determined by using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The all urease-encapsulated magnetic beads protected their stability of 30-45 % relative activity at 70 °C. A significant increase was observed at their pH stability compared with the free urease for both acidic and alkaline medium. Besides this, their repeatability activity were approximately 100 % during 4(th) run. They showed residual activity of 50 % after 16 weeks. The importance of this work is enhancement stability of immobilised urease by biocompatible polymer-conjugated magnetic beads for the industrial application based on removal of urea.

  7. Synthesis and characterisation of new types of side chain cholesteryl polymers.

    Science.gov (United States)

    Wang, Bin; Du, Haiyan; Zhang, Junhua

    2011-01-01

    A series of cholesterol derivatives have been synthesised via the alkylation reaction of the 3-hydroxyl group with the aliphatic bromide compounds with different chain lengths, namely 3β-alkyloxy-cholesterol. The double bond between the C5 and C6 positions in these cholesterol derivatives was oxidised into epoxy, followed by an epoxy-ring-opening reaction with the treatment with acrylic acid, resulting in a series of 3β-alkyloxy-5α-hydroxy-6β-acryloyloxycholesterol, C(n)OCh (n=1, 2, 4, 6, 8, 10, 12), The acrylate group is connected to the C6 position, which is confirmed by the single crystal structure analysis. The corresponding polymers, PC(n)OCh, were prepared via free radical polymerisation. The structure of monomers and the resulting polymers were characterised with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The thermal properties of PC(n)OCh were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). To determine the secondary structure of polymers, circular dichroism (CD) spectra were performed. It was found that not all monomers produce high-molecular-weight polymers because of steric hindrance. However, all polymers have a helical structure, which can be enhanced by increasing the alkoxy chain length. In addition, increasing the alkoxy chain length decreases the glass transition temperature and increases the decomposition temperature of the polymers.

  8. Methotrexate-conjugated quantum dots: synthesis, characterisation and cytotoxicity in drug resistant cancer cells.

    Science.gov (United States)

    Johari-Ahar, Mohammad; Barar, Jaleh; Alizadeh, Ali Mohammad; Davaran, Soodabeh; Omidi, Yadollah; Rashidi, Mohammad-Reza

    2016-01-01

    Methotrexate (MTX), a folic acid derivative, is a potent anticancer used for treatment of different malignancies, but possible initiation of drug resistance to MTX by cancer cells has limited its applications. Nanoconjugates (NCs) of MTX to quantum dots (QDs) may favour the cellular uptake via folate receptors (FRs)-mediated endocytosis that circumvents the efflux functions of cancer cells. We synthesised MTX-conjugated l-cysteine capped CdSe QDs (MTX-QD nanoconjugates) and evaluated their internalisation and cytotoxicity in the KB cells with/without resistancy to MTX. The NCs were fully characterised by high resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), dynamic light scattering (DLS) and optical spectroscopy. Upon conjugation with MTX, the photoluminescence (PL) properties of QDs altered, while an obvious quenching in PL of QDs was observed after physical mixing. The MTX-QD nanoconjugates efficiently internalised into the cancer cells, and induced markedly high cytotoxicity (IC50, 12.0 µg/mL) in the MTX-resistant KB cells as compared to the free MTX molecules (IC50,105.0 µg/mL), whereas, these values were respectively about 7.0 and 0.6 µg/mL in the MTX-sensitive KB cells. Based on these findings, the MTX-QD nanoconjugates are proposed for the targeted therapy of MTX-resistant cancers, which may provide an improved outcome in the relapsed FR-overexpressing cancers. PMID:26176269

  9. Synthesis and characterisation of new types of side chain cholesteryl polymers.

    Science.gov (United States)

    Wang, Bin; Du, Haiyan; Zhang, Junhua

    2011-01-01

    A series of cholesterol derivatives have been synthesised via the alkylation reaction of the 3-hydroxyl group with the aliphatic bromide compounds with different chain lengths, namely 3β-alkyloxy-cholesterol. The double bond between the C5 and C6 positions in these cholesterol derivatives was oxidised into epoxy, followed by an epoxy-ring-opening reaction with the treatment with acrylic acid, resulting in a series of 3β-alkyloxy-5α-hydroxy-6β-acryloyloxycholesterol, C(n)OCh (n=1, 2, 4, 6, 8, 10, 12), The acrylate group is connected to the C6 position, which is confirmed by the single crystal structure analysis. The corresponding polymers, PC(n)OCh, were prepared via free radical polymerisation. The structure of monomers and the resulting polymers were characterised with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The thermal properties of PC(n)OCh were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). To determine the secondary structure of polymers, circular dichroism (CD) spectra were performed. It was found that not all monomers produce high-molecular-weight polymers because of steric hindrance. However, all polymers have a helical structure, which can be enhanced by increasing the alkoxy chain length. In addition, increasing the alkoxy chain length decreases the glass transition temperature and increases the decomposition temperature of the polymers. PMID:21070795

  10. Characterisation of quaternary polymethacrylate films containing tartaric acid, metoprolol free base or metoprolol tartrate.

    Science.gov (United States)

    Glaessl, B; Siepmann, F; Tucker, I; Siepmann, J; Rades, T

    2009-11-01

    The aim of this study was to better understand the interactions between metoprolol tartrate and quaternary polymethacrylate (Eudragit RL and Eudragit RS) films. For reasons of comparison, polymeric films containing the free base metoprolol or free tartaric acid were also prepared. Systems containing various amounts of the free base, free acid and the salt were characterised using polarising light microscopy, X-ray powder diffraction, differential scanning calorimetry and mechanical analysis (puncture test). The free base is the most efficient plasticiser of the three species for Eudragit RL and Eudragit RS, but with limited solubility in the polymers. Due to its hydrophobicity, it can interact with the hydrophobic polymer backbones. In contrast, in salt containing films, ionic interactions between the positively charged quaternary ammonium groups and the negatively charged tartrate anions apparently occur, this being suggested by the different effects on Eudragit RL versus RS, which have different contents of quaternary ammonium groups. Importantly, the combination of acid and base as a salt avoids drug precipitation at higher metoprolol contents. The obtained new insight into the occurring drug-polymer interactions can help to facilitate the development/optimisation of this type of dosage forms.

  11. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    DEFF Research Database (Denmark)

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested...

  12. Synthesis of a nanorod ferrofluid and characterisation by magnetic-field-dependent small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Doebrich, F. [Universitaet des Saarlandes, Technische Physik, Geb. D2 2, 66041 Saarbruecken (Germany)]. E-mail: f.doebrich@nano.uni-saarland.de; Michels, A. [Universitaet des Saarlandes, Technische Physik, Geb. D2 2, 66041 Saarbruecken (Germany); Birringer, R. [Universitaet des Saarlandes, Technische Physik, Geb. D2 2, 66041 Saarbruecken (Germany)

    2007-09-15

    Compared to conventional ferrofluids, which contain mostly spherical particles, a dispersion of highly anisometric particles such as rods or chains is expected to give rise to an enhancement or modification of well-known ferrofluid properties. This contribution reports on the synthesis of a ferrofluid containing stable chains of iron nanoparticles and on its microstructural characterisation by means of transmission electron microscopy and small-angle X-ray scattering (SAXS). The SAXS measurements develop a pronounced anisotropy of the scattering pattern as a function of an increasing external magnetic field. Evaluation of the radially averaged SAXS curves in terms of basic scattering functions is discussed.

  13. Development of a SCAR (sequence-characterised amplified region) marker for acid resistance-related gene in Lactobacillus plantarum.

    Science.gov (United States)

    Liu, Shu-Wen; Li, Kai; Yang, Shi-Ling; Tian, Shu-Fen; He, Ling

    2015-03-01

    A sequence characterised amplified region marker was developed to determine an acid resistance-related gene in Lactobacillus plantarum. A random amplified polymorphic DNA marker named S116-680 was reported to be closely related to the acid resistance of the strains. The DNA band corresponding to this marker was cloned and sequenced with the induction of specific designed PCR primers. The results of PCR test helped to amplify a clear specific band of 680 bp in the tested acid-resistant strains. S116-680 marker would be useful to explore the acid-resistant mechanism of L. plantarum and to screen desirable malolactic fermentation strains.

  14. Synthesis of Two Natural Oleanolic Acid Saponins

    Institute of Scientific and Technical Information of China (English)

    LI, Chun-Xia; ZANG, Jing; WANG, Peng; ZHANG, Xiu-Li; GUAN, Hua-Shi; LI, Ying-Xia

    2006-01-01

    Ocean University of China, Qingdao, Shandong 266003, China3-O-[β-D-Glucopyranosyl-(1→3)-α-L-arabinopyranosyl]-oleanolic acid-28-O-[β-D-glucopyranosyl] ester 1 was synthesized concisely by a convergent strategy. Using stepwise fashion for the synthesis of saponin 2,3-O-{ [β-D-glucopyranosyl-( 1→ 2 ) ]-[ α-L-arabinopyranosyl-( 1→ 3 ) ]-α-L-arabinopyranosyl }-oleanolic acid-28-O-(β-D-glucopyranosyl) ester, an abnormal phenomenon, that the terminal arabinosyl residue took the 1C4 conformation instead of typical 4C1 form, was observed. Deprotection or heating could not resume the normal conformation,which resulted in the product of 2' not 2.

  15. Characterisation of a cell wall-anchored protein of Staphylococcus saprophyticus associated with linoleic acid resistance

    Directory of Open Access Journals (Sweden)

    King Nathan P

    2012-01-01

    Full Text Available Abstract Background The Gram-positive bacterium Staphylococcus saprophyticus is the second most frequent causative agent of community-acquired urinary tract infections (UTI, accounting for up to 20% of cases. A common feature of staphylococci is colonisation of the human skin. This involves survival against innate immune defenses including antibacterial unsaturated free fatty acids such as linoleic acid which act by disrupting bacterial cell membranes. Indeed, S. saprophyticus UTI is usually preceded by perineal skin colonisation. Results In this study we identified a previously undescribed 73.5 kDa cell wall-anchored protein of S. saprophyticus, encoded on plasmid pSSAP2 of strain MS1146, which we termed S. saprophyticus surface protein F (SssF. The sssF gene is highly prevalent in S. saprophyticus clinical isolates and we demonstrate that the SssF protein is expressed at the cell surface. However, unlike all other characterised cell wall-anchored proteins of S. saprophyticus, we were unable to demonstrate a role for SssF in adhesion. SssF shares moderate sequence identity to a surface protein of Staphylococcus aureus (SasF recently shown to be an important mediator of linoleic acid resistance. Using a heterologous complementation approach in a S. aureus sasF null genetic background, we demonstrate that SssF is associated with resistance to linoleic acid. We also show that S. saprophyticus strains lacking sssF are more sensitive to linoleic acid than those that possess it. Every staphylococcal genome sequenced to date encodes SssF and SasF homologues. Proteins in this family share similar predicted secondary structures consisting almost exclusively of α-helices in a probable coiled-coil formation. Conclusions Our data indicate that SssF is a newly described and highly prevalent surface-localised protein of S. saprophyticus that contributes to resistance against the antibacterial effects of linoleic acid. SssF is a member of a protein family

  16. Synthesis of 6E-Geranylgeraniol-19-oic Acid

    Institute of Scientific and Technical Information of China (English)

    LI Shu-hua; PENG Li-Zeng; LI Wei-dong; LI Yu-lin

    2003-01-01

    The present paper deals with the facile synthesis of 6E-geranylgeraniol-19-oic acid(1), a naturally occuring alicyclic diterpene acid, by a Horner-Wadsworth-Emmons olefination of two readily available fragments 7 and 3.

  17. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    OpenAIRE

    Isabel Bento; Teresa Duarte, M.; M. João M. Curto; Inês F. Antunes; Hélène Ramos; Fátima C. Teixeira

    2006-01-01

    A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2)nCO2R of different lengths (n = 0-6, 9, 10) are described.Nucleophilic substitution reactions on halo esters (X(CH2)nCO2R) by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultin...

  18. Selection of enhanced antimicrobial activity posing lactic acid bacteria characterised by (GTG)5-PCR fingerprinting.

    Science.gov (United States)

    Šalomskienė, Joana; Abraitienė, Asta; Jonkuvienė, Dovilė; Mačionienė, Irena; Repečkienė, Jūratė

    2015-07-01

    The aim of the study was a detail evaluation of genetic diversity among the lactic acid bacteria (LAB) strains having an advantage of a starter culture in order to select genotypically diverse strains with enhanced antimicrobial effect on some harmfull and pathogenic microorganisms. Antimicrobial activity of LAB was performed by the agar well diffusion method and was examined against the reference strains and foodborne isolates of Bacillus cereus, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Antifungal activity was tested against the foodborne isolates of Candida parapsilosis, Debaromyces hansenii, Kluyveromyces marxianus, Pichia guilliermondii, Yarowia lipolytica, Aspergillus brasiliensis, Aspergillus versicolor, Cladosporium herbarum, Penicillium chrysogenum and Scopulariopsis brevicaulis. A total 40 LAB strains representing Lactobacillus (23 strains), Lactococcus (13 strains) and Streptococcus spp. (4 strains) were characterised by repetitive sequence based polymerase chain reaction fingerprinting which generated highly discriminatory profiles, confirmed the identity and revealed high genotypic heterogeneity among the strains. Many of tested LAB demonstrated strong antimicrobial activity specialised against one or few indicator strains. Twelve LAB strains were superior in suppressing growth of the whole complex of pathogenic bacteria and fungi. These results demonstrated that separate taxonomic units offered different possibilities of selection for novel LAB strains could be used as starter cultures enhancing food preservation.

  19. Selection of enhanced antimicrobial activity posing lactic acid bacteria characterised by (GTG)5-PCR fingerprinting.

    Science.gov (United States)

    Šalomskienė, Joana; Abraitienė, Asta; Jonkuvienė, Dovilė; Mačionienė, Irena; Repečkienė, Jūratė

    2015-07-01

    The aim of the study was a detail evaluation of genetic diversity among the lactic acid bacteria (LAB) strains having an advantage of a starter culture in order to select genotypically diverse strains with enhanced antimicrobial effect on some harmfull and pathogenic microorganisms. Antimicrobial activity of LAB was performed by the agar well diffusion method and was examined against the reference strains and foodborne isolates of Bacillus cereus, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Antifungal activity was tested against the foodborne isolates of Candida parapsilosis, Debaromyces hansenii, Kluyveromyces marxianus, Pichia guilliermondii, Yarowia lipolytica, Aspergillus brasiliensis, Aspergillus versicolor, Cladosporium herbarum, Penicillium chrysogenum and Scopulariopsis brevicaulis. A total 40 LAB strains representing Lactobacillus (23 strains), Lactococcus (13 strains) and Streptococcus spp. (4 strains) were characterised by repetitive sequence based polymerase chain reaction fingerprinting which generated highly discriminatory profiles, confirmed the identity and revealed high genotypic heterogeneity among the strains. Many of tested LAB demonstrated strong antimicrobial activity specialised against one or few indicator strains. Twelve LAB strains were superior in suppressing growth of the whole complex of pathogenic bacteria and fungi. These results demonstrated that separate taxonomic units offered different possibilities of selection for novel LAB strains could be used as starter cultures enhancing food preservation. PMID:26139877

  20. Electrochemical synthesis and characterisation of hybrid materials polypyrrole/dodecatungstophosphate as protective agents against steel corrosion

    Science.gov (United States)

    Bonastre Cano, Jose Antonio

    hand, this pretreatment should guarantee appropriate conditions in order to obtain a coating with high adhesion on carbon steel. Once studied the better parameters for the synthesis of the hybrid material by cyclic voltammetry, hybrid material is morphological, chemical and electrochemical characterised by the following techniques: Cyclic Voltammetry, Scanning Electron Microscopy, Energy Dispersive X Ray, X Ray Photoelectron Spectroscopy and Electrochemical Impedance Spectroscopy. The hybrid material polypyrrole/PW 12O403-. chemical structure presents Fe oxides and hydroxide within the polypyrrole polycationic matrix. Hybrid material polypyrrol/PW12O403- diminishes the corrosion of carbon steel in NaOH and Porland cement filtering solutions. These cement solutions simulate the pore fluid conditions existing in cured mortar or concrete elements. Fe ion concentration data were determinated in corrosion tests. Voltammetric response of polymeric coatings was evaluated by cyclic voltammetry. Finally, the protection provided by hybrid material polypyrrole/PW 12O403, in oxidised and reduced state, was evaluated on carbon steel electrodes embedded in Portland cement mortars immersed in seawater and submitted to an accelerated carbonation process for 265 days. Polymeric material covered carbon steel electrodes in reduced state suffer a Fe gravimetric loss 15 times lower than the ones of bare electrodes against chlorides attack, due to the effect of physical barrier. Hybrid material covered electrodes in oxidised state after being submitted to a carbonation process suffer a Fe gravimetric loss 2.5 times lower than the ones of bare electrodes, due to galvanic protection provided by hybrid material polypyrrole/PW 12O403- on carbon steel.

  1. Synthesis and Characterisation of Bis-(chloromethyl Oxetane, its Homopolymer and Copolymer with Tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    T. S. Reddy

    2006-07-01

    Full Text Available Bis-(chloromethyl oxetane (BCMO was synthesised from pentaerythritol by chlorination,followed by ring closure. It was polymerised using BF3-etherate and butanediol system, similarlythe BCMO–THF (tetrahydrofuran copolymer was also synthesised. The monomers and thepolymers were characterised by IR, 1H-NMR and molecular weight. Flame retardant propertiesof the poly-BCMO were also investigated.

  2. Catalysis of the Carbonylation of Alcohols to Carboxylic Acids Including Acetic Acid Synthesis from Methanol.

    Science.gov (United States)

    Forster, Denis; DeKleva, Thomas W.

    1986-01-01

    Monsanto's highly successful synthesis of acetic acid from methanol and carbon monoxide illustrates use of new starting materials to replace pretroleum-derived ethylene. Outlines the fundamental aspects of the acetic acid process and suggests ways of extending the synthesis to higher carboxylic acids. (JN)

  3. The Synthesis Technique of Polyacrylic Acid Superplasticizer

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rongguo; LI Qiong; ZHANG Anfu; LIU Yong; LEI Jiaheng

    2008-01-01

    Using water separation technique,acrylic acid (AA) and polyethylene glycol (PEG) 1000,of which the ratio was 1.5,were esterified and the optimum esterification ratio of 90% could be reached under the condition of 110 ℃×3 h.Using polyoxyethylene acrylate macromonomer (PA) prepared in the esterification,AA and sodium methylacryl sulfonate (MAS) as monomers,a copolymer which could be used as superplasticizer was prepared by free radical copolymerization in n(PA);n(AA) :n(MAS) of 1 ;7 :3.When the synthesis condition was 80 ℃×5 h,the optimal dosage of initiator was 3.0%-4.0%,the fluidity of cement paste with the samples could reach 270 mm.By analyzing the effect of the content of residual small molecule sulfonic monomer on the properties of sample,n(MAS)/n(PA) was controlled in a range of 2.5-3.8.

  4. Towards molecular systems capable of self-assembly on gold surfaces: synthesis and characterisation of ruthenium and osmium based terpyridine complexes

    OpenAIRE

    Tasca, Stefania

    2005-01-01

    The synthesis, spectroscopic and electrochemical characterisation of Ru(II) and Os(II) mononuclear complexes are described. Special attention is paid to the synthesis of a new series of terpyridine complexes capable of self-assembled on gold surfaces such as pyridine or thiol group. Chapter 1 is an introductory chapter in that the basic concepts regarding Ru(II) polypyridyl chemistry are introduced and explained. The parent complex [Ru(bpy)3]2+ is examined along with its photochemical and...

  5. Isolation, characterisation and synthesis of insecticidal natural products of the Myrtaceae family

    OpenAIRE

    Beddie, David G.

    1998-01-01

    New insecticidal natural products are required to find compounds with higher intrinsic activities to lower field application rates, and with novel modes of action to combat insect pest species which have developed resistance to current commercial insecticides. Using a taxonomic approach, studies on plants of the Myrtaceae family led to the isolation and characterisation of a range of insecticidal natural products 1 - 9 (figure 1). These compounds are all structurally related as they conta...

  6. Synthesis and characterisation of 5-acyl-6,7-dihydrothieno[3,2-c]pyridine inhibitors of Hedgehog acyltransferase

    Directory of Open Access Journals (Sweden)

    Thomas Lanyon-Hogg

    2016-06-01

    Full Text Available In this data article we describe synthetic and characterisation data for four members of the 5-acyl-6,7-dihydrothieno[3,2-c]pyridine (termed “RU-SKI” class of inhibitors of Hedgehog acyltransferase, including associated NMR spectra for final compounds. RU-SKI compounds were selected for synthesis based on their published high potencies against the enzyme target. RU-SKI 41 (9a, RU-SKI 43 (9b, RU-SKI 101 (9c, and RU-SKI 201 (9d were profiled for activity in the related article “Click chemistry armed enzyme linked immunosorbent assay to measure palmitoylation by Hedgehog acyltransferase” (Lanyon-Hogg et al., 2015 [1]. 1H NMR spectral data indicate different amide conformational ratios between the RU-SKI inhibitors, as has been observed in other 5-acyl-6,7-dihydrothieno[3,2-c]pyridines. The synthetic and characterisation data supplied in the current article provide validated access to the class of RU-SKI inhibitors.

  7. Synthesis and Characterisation of Porous Titania-Silica Composite Aerogel for NO(x) and Acetaldehyde Removal.

    Science.gov (United States)

    Lee, Kwang Young; Park, Se Min; Kim, Jong Beom; El Saliby, Ibrahim; Shahid, Mohammad; Kim, Geon-Joong; Shon, Ho Kyong; Kim, Jong-Ho

    2016-05-01

    In this study, the synthesis of porous titania-silica (TiO2-SiO2) composite aerogel at ambient pressure by using non-hazardous chemicals as a source of silica was investigated. TiO2-SiO2 composite aerogels were characterised and their photocatalytic performances were investigated for the removal efficiency of acetaldehyde and NO(x) under UV light. Results showed that porous composite aerogel with aggregated morphology, high surface area and an increased mesoporosity were formed. TiO2-SiO2(1.8) composite, with high Ti/Si ratio, showed the best results in terms of photocatalytic removal of acetaldehyde and nitrogen oxide.

  8. Synthesis and characterisation of metal nanoparticles and their effects on seed germination and seedling growth in commercially important Eruca sativa.

    Science.gov (United States)

    Zaka, Mehreen; Abbasi, Bilal Haider; Rahman, Latif-Ur; Shah, Afzal; Zia, Muhammad

    2016-06-01

    The synthesis, characterisation and application of metal nanoparticles have become an important and attractive branch of nanotechnology. In current study, metallic nanoparticles of silver, copper, and gold were synthesised using environment friendly method (polyols process), and applied on medicinally important plant: Eruca sativa. Effects of application of these nanoparticles were evaluated on seed germination frequency and biochemical parameters of plant tissues. Seeds of E. sativa were germinated on Murashige and Skoog (MS) medium incorporated with various combinations of nanoparticles suspension (30 µg/ml). Phytotoxicity study showed that nanoparticles could induce stress in plants by manipulating the endogenous mechanisms. In response to these stresses, plants release various defensive compounds; known as antioxidant secondary metabolites. These plants derived secondary metabolites having a great potential in treating the common human ailments. In the authors study, small-sized nanoparticles showed higher toxicity levels and enhanced secondary metabolites production, total protein content, total flavonoids content and total phenolics content. PMID:27256893

  9. Synthesis and characterisation of a novel mixed donor P,O,P' nixantphos ligand and its metal complex

    Science.gov (United States)

    Marimuthu, Thashree; Bala, Muhammad D.; Friedrich, Holger B.

    2016-02-01

    The complex [(NixC8OH)Ir(cod)Cl] 4 has been synthesized and structurally characterized by NMR, IR and single crystal X-ray diffraction. The synthesis and characterisation of the novel ligand NixC8OH is also presented. The coordination around Ir is trigonal bipyramidal with both P groups of the NixC8OH ligand bound in a bis-equatorial mode. The bis-chelating cod (C8H12) ligand occupies the remaining equatorial position and an axial position. This mode of bonding has resulted in a large bite angle (P1-Ir-P2) of 102.92(12)° for the title complex 4. The IR and NMR data further support the elucidated structure. Thermal analyses of 4 indicate that it is thermally stable up to a decomposition temperature of >400 °C.

  10. Synthesis and Characterisation of Porous Titania-Silica Composite Aerogel for NO(x) and Acetaldehyde Removal.

    Science.gov (United States)

    Lee, Kwang Young; Park, Se Min; Kim, Jong Beom; El Saliby, Ibrahim; Shahid, Mohammad; Kim, Geon-Joong; Shon, Ho Kyong; Kim, Jong-Ho

    2016-05-01

    In this study, the synthesis of porous titania-silica (TiO2-SiO2) composite aerogel at ambient pressure by using non-hazardous chemicals as a source of silica was investigated. TiO2-SiO2 composite aerogels were characterised and their photocatalytic performances were investigated for the removal efficiency of acetaldehyde and NO(x) under UV light. Results showed that porous composite aerogel with aggregated morphology, high surface area and an increased mesoporosity were formed. TiO2-SiO2(1.8) composite, with high Ti/Si ratio, showed the best results in terms of photocatalytic removal of acetaldehyde and nitrogen oxide. PMID:27483782

  11. Synthesis and characterisation of metal nanoparticles and their effects on seed germination and seedling growth in commercially important Eruca sativa.

    Science.gov (United States)

    Zaka, Mehreen; Abbasi, Bilal Haider; Rahman, Latif-Ur; Shah, Afzal; Zia, Muhammad

    2016-06-01

    The synthesis, characterisation and application of metal nanoparticles have become an important and attractive branch of nanotechnology. In current study, metallic nanoparticles of silver, copper, and gold were synthesised using environment friendly method (polyols process), and applied on medicinally important plant: Eruca sativa. Effects of application of these nanoparticles were evaluated on seed germination frequency and biochemical parameters of plant tissues. Seeds of E. sativa were germinated on Murashige and Skoog (MS) medium incorporated with various combinations of nanoparticles suspension (30 µg/ml). Phytotoxicity study showed that nanoparticles could induce stress in plants by manipulating the endogenous mechanisms. In response to these stresses, plants release various defensive compounds; known as antioxidant secondary metabolites. These plants derived secondary metabolites having a great potential in treating the common human ailments. In the authors study, small-sized nanoparticles showed higher toxicity levels and enhanced secondary metabolites production, total protein content, total flavonoids content and total phenolics content.

  12. Methane Sulphonic Acid is Green Catalyst in Organic Synthesis

    OpenAIRE

    Pramod Kulkarni

    2015-01-01

    Methane sulphonic acid is an alkanesulphonic acid and its chemical formula is CH3SO3H. MSA is a strong acid having pKa= 1.9 and completely ionized in 0.1 M in an aqueous solution and has small affinity to oxidize organic compounds, less corrosive and toxic than other mineral acids. MSA is also biodegradable and not evolve toxic gases. Therefore MSA is considered as green acid. Therefore its use in organic synthesis attracts many chemists to use in organic synthesis. In this review we describe...

  13. Electrocatalysts for the oxygen evolution electrode in water electrolysers using proton exchange membranes : synthesis and characterisation

    OpenAIRE

    Marshall, Aaron

    2005-01-01

    Electrocatalysts based on IrO2 have been synthesised and characterised using a wide range of techniques. These oxide materials were primarily developed as oxygen evolution electrocatalysts for proton exchange membrane (PEM) water electrolysis. This development has enabled high performances to be achieved in a PEM water electrolysis cell. Overall the best result was obtained with an Ir0.6Ru0.4O2 anode and 20 wt% Pt/C cathode, with a cell voltage of 1.567 V at 1 A cm−2 and 80 °C when using Nafi...

  14. Synthesis and characterisation of ruthenium carbonyl complexes with cyclometallated ligands derived from senecialdimine

    NARCIS (Netherlands)

    Mul, WP; Elsevier, CJ; Vuurman, MA; Smeets, WJJ; Spek, AL; deBoer, JL

    1997-01-01

    From thermal reactions of Ru-3(CO)(12) with senecialdimine, (CH3)(2)C=CHCH=NR (R = iPr (a), t-Bu (b)), in refluxing heptanes the following complexes have been isolated and characterised: Ru-2(CO)(6)[(CH3)(2)C(H)CC(H)NR] (2a,b), Ru-2(Co)(6)[C(H)C(CH3)C(H)C(H)=NR] (3a,b), [HRu6(CO)(18)][2-(C(H)=C(CH3)

  15. Automated solid-phase synthesis of oligosaccharides containing sialic acids

    Directory of Open Access Journals (Sweden)

    Chian-Hui Lai

    2015-05-01

    Full Text Available A sialic acid glycosyl phosphate building block was designed and synthesized. This building block was used to prepare α-sialylated oligosaccharides by automated solid-phase synthesis selectively.

  16. Genetics Home Reference: congenital bile acid synthesis defect type 2

    Science.gov (United States)

    ... DEFECT, CONGENITAL, 2 Sources for This Page Clayton PT. Disorders of bile acid synthesis. J Inherit Metab ... J, Duran M, Overmars H, Scambler PJ, Clayton PT. Mutations in SRD5B1 (AKR1D1), the gene encoding delta( ...

  17. Synthesis and analytical characterisation of copper-based nanocoatings for bioactive stone artworks treatment.

    Science.gov (United States)

    Ditaranto, Nicoletta; Loperfido, Sabrina; van der Werf, Inez; Mangone, Annarosa; Cioffi, Nicola; Sabbatini, Luigia

    2011-01-01

    Biological agents play an important role in the deterioration of cultural heritage causing aesthetic, biogeophysical and biogeochemical damages. Conservation is based on the use of preventive and remedial methods. The former aims at inhibiting biological attack, and the latter aims at eradicating the biological agents responsible for biodeterioration. Here, we propose the preparation and the analytical characterisation of copper-based nanocoating, capable of acting both as a remedy and to prevent microbial proliferation. Core-shell CuNPs are mixed with a silicon-based product, commonly used as a water-repellent/consolidant, to obtain a combined bioactive system to be applied on stone substrates. The resulting coatings exert a marked biological activity over a long period of time due to the continuous and controlled release of copper ions acting as biocides. To the best of our knowledge, this is the first time that a multifunctional material is proposed, combining the antimicrobial properties of nanostructured coatings with those of the formulations applied to the restoration of stone artworks. A complete characterisation based on a multi-technique analytical approach is presented. PMID:20972773

  18. Synthesis and Characterisation of Bis-azido Methyl Oxetane and its Polymer and Copolymer with Tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    J. K. Nair

    2002-04-01

    Full Text Available Bis-azido methyl oxetane (BAMO was synthesised from pentaerythritol in two steps. Pentaerythritol was chlorinated to yield a mixture of mono, di, tri and tetra chloro compounds. The trichloro compound on ring closure gives bis-chloro methyl oxetane (BCMO. It was reacted with sodium azide in aqueous medium to obtain BAMO. The latter was polymerised using BF3 etherate catalyst and 1,4-butanediol initiator. Similarly, the BAMO- THF copolymer was also synthesised. All the monomers and polymers were characterised by IR, 1H-NMR, 13C-NMR, and refractive index. The polymers were also characterised for molecular weight, hydroxyl value, etc. Thermal analysis showed that both polymers degrade exothermically with T max of 237 °C for poly BAMO and 241°C for BAMO- THF copolymer with activation energy of 39 kcal/mol and 40 kcal/mol, respectively. Explosive properties like impact and friction sensitivity of BAMO and the other polymers were also determined.

  19. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Isabel Bento

    2006-11-01

    Full Text Available A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2nCO2R of different lengths (n = 0-6, 9, 10 are described.Nucleophilic substitution reactions on halo esters (X(CH2nCO2R by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultinuclear NMR and IR spectroscopies, MS spectrometry and elemental analysis; theNMR spectroscopic data were used for structural assignment of the N-1 and N-2 isomers.The molecular structure of indazol-2-yl-acetic acid (5b was determined by X-raydiffraction, which shows a supramolecular architecture involving O2-H...N1intermolecular hydrogen bonds.

  20. Synthesis, characterisation, and oxygen atom transfer reactions involving the first gold(I)-alkylperoxo complexes.

    Science.gov (United States)

    Collado, Alba; Gómez-Suárez, Adrián; Oonishi, Yoshihiro; Slawin, Alexandra M Z; Nolan, Steven P

    2013-11-25

    The synthesis of a new class of organogold species containing a peroxo moiety is reported. Complexes [Au(IPr)(OO(t)Bu)] and [Au(SIPr)(OO(t)Bu)] have been synthesised via a straightforward methodology using the parent gold(I) hydroxide complexes as synthons. These complexes have been successfully used in oxygen-transfer reactions to triphenylphosphine.

  1. Preliminary studies of consolidation of wall paintings: synthesis and characterisation of nanolime

    Directory of Open Access Journals (Sweden)

    Penka I. Girginova

    2016-01-01

    Full Text Available In this publication, we report the synthesis and characterization of calcium and magnesium hydroxides nanoparticles for consolidation of mural paintings. Some preliminary results are discussed. This research is the initial part of our ongoing project which aims to develop new synthetic strategies towards novel and innovative materials for preservation and restoration of old renders.

  2. Synthesis and characterisation of substrate-based peptides as inhibitors of histone demethylase KDM4C

    DEFF Research Database (Denmark)

    Nielsen, Simon D; Leurs, Ulrike; Bergner, Magnus;

    2016-01-01

    The design and synthesis of modified pentapeptides based on a truncated version of the substrate for KDM4C, a histone lysine demethylase (KDM), and investigation of their inhibitory activity at KDM4C is reported. By modifying the lysine residue corresponding to lysine 9 at histone 3 (H3K9), three...

  3. Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia

    Science.gov (United States)

    Weber, Arthur L.

    1998-01-01

    Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.

  4. Gold(III)pentafluorophenylarylazoimidazole: Synthesis and spectral (H, C, COSY, HMQC NMR) characterisation

    Indian Academy of Sciences (India)

    Prithwiraj Byabartta; Mariano Laguna

    2006-09-01

    Reaction of [AuIII(C6F5)3(tht)] with RaaiR' in dichloromethane medium leads to [AuIII(C6F5)3 (RaaiR')] [RaaiR' = -R-C6H4-N=N-C3H2-NN-1-R', (1-3), R = H (a), Me (b), Cl (c) and R' = Me (1), CH2CH3 (2), CH2Ph (3), tht is tetrahydrothiophen]. The nine new complexes are characterised by ES/MS as well as FAB, IR and multinuclear NMR (1H, 13C, 19F) spectroscopic studies. In addition to dimensional NMR studies as 1H, 1H COSY and 1H 13C HMQC permit complete assignment of the complexes in the solution phase.

  5. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    2014-01-01

    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order...... to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved....

  6. Induction of phytic acid synthesis by abscisic acid in suspension-cultured cells of rice

    OpenAIRE

    Matsuno, Koya; Fujimura, Tatsuhito

    2014-01-01

    A pathway of phytic acid (PA) synthesis in plants has been revealed via investigations of low phytic acid mutants. However, the regulation of this pathway is not well understood because it is difficult to control the environments of cells in the seeds, where PA is mainly synthesized. We modified a rice suspension culture system in order to study the regulation of PA synthesis. Rice cells cultured with abscisic acid (ABA) accumulate PA at higher levels than cells cultured without ABA, and PA a...

  7. Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

    International Nuclear Information System (INIS)

    A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  8. Hydrogel/bioactive glass composites for bone regeneration applications: Synthesis and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Killion, John A., E-mail: jkillion@research.ait.ie [Materials Research Institute, Athlone Institute of Technology, Dublin Rd, Athlone, Co. Westmeath (Ireland); Kehoe, Sharon, E-mail: sh625116@dal.ca [Department of Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 34R2 (Canada); Geever, Luke M., E-mail: lgeever@ait.ie [Materials Research Institute, Athlone Institute of Technology, Dublin Rd, Athlone, Co. Westmeath (Ireland); Devine, Declan M., E-mail: ddevine@ait.ie [Materials Research Institute, Athlone Institute of Technology, Dublin Rd, Athlone, Co. Westmeath (Ireland); Sheehan, Eoin, E-mail: eoinsheehan@aol.com [Department of Trauma and Orthopaedics, MRHT, Tullamore, Co. Offaly (Ireland); Boyd, Daniel, E-mail: d.boyd@dal.ca [Department of Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 34R2 (Canada); Higginbotham, Clement L., E-mail: chigginbotham@ait.ie [Materials Research Institute, Athlone Institute of Technology, Dublin Rd, Athlone, Co. Westmeath (Ireland)

    2013-10-15

    Due to the deficiencies of current commercially available biological bone grafts, alternative bone graft substitutes have come to the forefront of tissue engineering in recent times. The main challenge for scientists in manufacturing bone graft substitutes is to obtain a scaffold that has sufficient mechanical strength and bioactive properties to promote formation of new tissue. The ability to synthesise hydrogel based composite scaffolds using photopolymerisation has been demonstrated in this study. The prepared hydrogel based composites were characterised using techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrometry (EDX), rheological studies and compression testing. In addition, gel fraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), porosity and swelling studies of the composites were carried out. It was found that these novel hydrogel bioglass composite formulations did not display the inherent brittleness that is typically associated with bioactive glass based bone graft materials and exhibited enhanced biomechanical properties compared to the polyethylene glycol hydrogel scaffolds along. Together, the combination of enhanced mechanical properties and the deposition of apatite on the surface of these hydrogel based composites make them an ideal candidate as bone graft substitutes in cancellous bone defects or low load bearing applications. Highlights: • Young's modulus increases with the addition of bioactive glasses. • Hydrogel based composites formed an apatite layer in simulated body fluid. • Storage modulus increases with addition of bioactive glasses. • Compressive strength is dependent on molecular weight and bioactive glass loading.

  9. Synthesis and characterisation of poly(acryalamide) grafted carboxymethyl xanthan gum copolymer.

    Science.gov (United States)

    Badwaik, Hemant Ramchandra; Sakure, Kalyani; Alexander, Amit; Ajazuddin; Dhongade, Hemant; Tripathi, Dulal Krishna

    2016-04-01

    In the present work, an unreported graft copolymer of carboxymethyl xanthan gum and acrylamide has been synthesised by free radical polymerisation in a nitrogen atmosphere using ammonium persulphate as an initiator. The optimum reaction conditions adopted for affording maximum percentage of grafting including its grafting efficiency were obtained by varying the concentration of carboxymethyl xanthan gum from 4 to 24 g dm(-3); ammonium persulphate from 5×10(-4) to 30×10(-4)mol dm(-3); acrylamide from 0.4 to 1.2 mol dm(-3); reaction temperature from 55 to 75°C and reaction time from 30 to 90 min. The synthesised graft copolymer has been characterised by (1)H NMR, FTIR spectroscopy, X-ray diffraction measurement, thermal analysis, viscosity measurement and scanning electron microscopy. However, grafting of acrylamide onto carboxymethyl xanthan gum backbone enhanced its thermal stability. This graft copolymer might be well exploited globally as a potential carrier for drug delivery system. PMID:26772913

  10. Synthesis and Characterisation of Struvite Family Crystals by An Aqueous Precipitation Method

    Directory of Open Access Journals (Sweden)

    Sutiyono S.

    2016-01-01

    Full Text Available Struvite (NH4MgPO4•6H2O is a mineral often found as a scale deposit in an industrial process and piping. The common occurrence of struvite formation is a wide variety of environments. pH solution and environmental temperature are important parameters that control precipitation and subsequent decomposition of struvite. The study aims to characterise the struvite precipitated out the solution through chemical and mineralogical analysis. In this work, struvite solution was prepared by mixing NH4OH , MgCl2 and H3PO4 with the different purity grade (A and B in the mol ratio of 1 : 1 : 1 in the stirred glass vessel tank with volume of 500 ml, and then stirred at 200 rpm for 70 minutes. Temperature of 3°C and an initial pH of 10 were selected. The precipitated deposit was dried at room temperature for 48 hours of being analyzed. Material characterization of the deposits was conducted using XRPD Rietveld method of qualitative and quantitative mineralogical phase analysis. XRF was employed for bulk chemical elemental analysis of the scale obtained. The sample A using analytical grade powder provided the major phases of struvite-(K and struvite. In constrast, the major phase of newberyite and minor phases of lepidocrocite (FeOOH and niter (KNO3 was observed by following changes in the lowest purity of powder (Sample B. Analysis of the experimental data suggests a solution mediated transformation process as a possible mechanism of struvite transformation.

  11. Cyclopentadithiophene–naphthalenediimide polymers; synthesis, characterisation, and n-type semiconducting properties in field-effect transistors and photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun-Han [Department of Chemical Engineering, Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University, 101, Sec. 2, Kuang-Fu Road, Hsin-Chu 30013, Taiwan (China); Kettle, Jeff [School of Electronics, Bangor University, Dean st., Bangor, Gwynedd, LL57 1UT Wales (United Kingdom); Horie, Masaki, E-mail: mhorie@mx.nthu.edu.tw [Department of Chemical Engineering, Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University, 101, Sec. 2, Kuang-Fu Road, Hsin-Chu 30013, Taiwan (China)

    2014-04-01

    The synthesis, characterisation, and device performance of a series of cyclopentadithiophene (CPDT)-naphthalenediimide (NDI) donor-acceptor-donor (D-A-D) polymers is reported. The monomers with various alkyl chains are synthesised via direct arylation using palladium complex catalyst. The monomers are then polymerised by oxidative polymerisation using FeCl{sub 3} to provide high molecular weight polymers (M{sub n} = 21,800–76,000). The polymer films show deep-red absorption including near-infrared region up to 1100 nm to give optical bandgap of approximately 1.16 eV. The polymers exhibit only n-type semiconducting properties giving the highest electron mobility of 9 × 10{sup -3} cm{sup 2} V{sup −1} s{sup −1} in organic field-effect transistors (OFETs). Organic photovoltaic (OPV) devices are fabricated from solutions of the polymers as acceptors and poly(3-hexylthiophene) (P3HT) as a donor. - Highlights: • Cyclopentadithiophene–naphthalenediimide oligomers were prepared by direct arylation. • The oligomers were polymerised by oxidative reaction using iron(III)chloride. • The polymer films show deep-red absorption up to 1100 nm with a bandgap of 1.1 eV. • The polymers exhibit only n-type semiconducting properties in OFETs and OPVs.

  12. Facile synthesis of mosquitocidal silver nanoparticles using Mussaenda glabra leaf extract: characterisation and impact on non-target aquatic organisms.

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L; Nicoletti, Marcello; Benelli, Giovanni

    2016-11-01

    Plant-borne compounds have been proposed for extracellular synthesis of mosquitocidal nanoparticles. However, their impact against mosquito natural enemies has been scarcely studied. Here, we synthesised silver nanoparticles (Ag NPs) using Mussaenda glabra leaf extract as reducing and stabilising agent. Biofabricated Ag NPs were characterised by UV-vis spectrophotometry, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared to the leaf aqueous extract, biosynthesised Ag NPs showed higher toxicity against mosquito vectors Anopheles subpictus, Aedes albopictus and Culex tritaeniorhynchus with LC50 of 17-19 μg/mL, respectively. Ag NPs were found safer to non-target organisms Diplonychus indicus and Gambusia affinis, with respective LC50 values ranging from 1446 to 8628 μg/mL. Overall, M. glabra-fabricated Ag NPs are a promising and eco-friendly tool against larval populations of mosquito vectors of medical and veterinary importance, with negligible toxicity against other non-target aquatic organisms.

  13. Chemical synthesis, characterisation, analytical method development and control to promote exposure assessments and toxicological testing. Highlights from COMPARE

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, Aa.; Malmberg, T.; Weiss, J. [Stockholm Univ. (Sweden). Dept. of Environmental Chemistry

    2004-09-15

    The issue of endocrine disruptor effects in wildlife and humans grow increasingly important during the 1990s'. As part of the focus on endocrine disruptors new contaminants and their metabolites were put forward for studies with endpoints related to hormone disruption. One such large group of chemicals and/or metabolites of neutral semi-persistent or persistent compounds was the substituted phenols, particularly the halogenated phenolic compounds (HPCs). Polychlorobiphenylols (OHPCBs) were reported to be strongly retained in human blood plasma in 1995 and this article was the first study to point out the general retention of several OH-PCBs in the plasma. The metabolic formation of OH-PCBs was well known and the specific blood retention had been reported for at least one PCB congener, 3,3',4,4'-tetrachlorobiphenyl (CB-77) in some previous studies. The identification of OH-PCBs being retained in blood and their specific binding to transthyretin (TTR) has formed much of the basis for two EU R and D programs, first RENCO and now COMPARE. The present report is aimed to highlight some of the results obtained within the COMPARE program mainly dealing with the chemical synthesis, characterisation and analytical aspects of HPCs.

  14. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  15. Synthesis, characterisation and stability of Cu2O nanoparticles produced via reverse micelles microemulsion

    International Nuclear Information System (INIS)

    Cuprite (Cu2O) nanoparticles were synthesized at room temperature via reduction of CuCl2.2H2O by NaBH4 in water/n-heptane microemulsion stabilised by the non-ionic Brij30 surfactant. Whole Powder Pattern Modelling of the X-ray diffraction patterns shows the presence of a bimodal size distribution in the nanopowders, with a fraction of domains in the 10-40 nm range and a smaller one below 10 nm. Linear and planar defects are absent. A relationship between the average size of the larger particles and the quantity of water in the system was obtained. The stability of cuprite under visible light irradiation both during the synthesis and after the preparation was investigated, showing that a self-catalytic conversion of Cu2O into CuO takes place in water.

  16. Synthesis, characterisation and stability of Cu{sub 2}O nanoparticles produced via reverse micelles microemulsion

    Energy Technology Data Exchange (ETDEWEB)

    Dodoo-Arhin, D. [University of Trento, Department of Materials Engineering and Industrial Technologies, via Mesiano 77, 38100 Trento (Italy); Leoni, M., E-mail: Matteo.Leoni@unitn.it [University of Trento, Department of Materials Engineering and Industrial Technologies, via Mesiano 77, 38100 Trento (Italy); Scardi, P. [University of Trento, Department of Materials Engineering and Industrial Technologies, via Mesiano 77, 38100 Trento (Italy); Garnier, E. [Laboratoire de Catalyse en Chimie Organique, UMR CNRS 6503, Universite de Poitiers, 40 Av. du Recteur Pineau, 86022 Poitiers (France); Mittiga, A. [ENEA C.R. Casaccia, via Anguillarese 301, 00123 Roma (Italy)

    2010-08-01

    Cuprite (Cu{sub 2}O) nanoparticles were synthesized at room temperature via reduction of CuCl{sub 2}.2H{sub 2}O by NaBH{sub 4} in water/n-heptane microemulsion stabilised by the non-ionic Brij30 surfactant. Whole Powder Pattern Modelling of the X-ray diffraction patterns shows the presence of a bimodal size distribution in the nanopowders, with a fraction of domains in the 10-40 nm range and a smaller one below 10 nm. Linear and planar defects are absent. A relationship between the average size of the larger particles and the quantity of water in the system was obtained. The stability of cuprite under visible light irradiation both during the synthesis and after the preparation was investigated, showing that a self-catalytic conversion of Cu{sub 2}O into CuO takes place in water.

  17. Synthesis and characterisation of highly fluorescent core-shell nanoparticles based on Alexa dyes

    Energy Technology Data Exchange (ETDEWEB)

    Natte, Kishore; Behnke, Thomas; Orts-Gil, Guillermo, E-mail: guillermo.orts-gil@bam.de; Wuerth, Christian; Friedrich, Joerg F.; Oesterle, Werner; Resch-Genger, Ute, E-mail: ute.resch@bam.de [BAM Federal Institute for Materials Research and Testing (Germany)

    2012-02-15

    Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophore-labelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor. Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles.

  18. Co(II) and Cd(II) Complexes Derived from Heterocyclic Schiff-Bases: Synthesis, Structural Characterisation, and Biological Activity

    Science.gov (United States)

    Ahmed, Riyadh M.; Yousif, Enaam I.; Al-Jeboori, Mohamad J.

    2013-01-01

    New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L1) and N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L2) are reported. Schiff-base ligands L1 and L2 were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)2]Cl2 (where M = Co(II) or Cd(II), L = L1 or L2) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, 1H, and 13C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G−) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands. PMID:24027449

  19. Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments

    OpenAIRE

    Król, Bożena; Król, Piotr; Pikus, Stanisław; Chmielarz, Paweł; Skrzypiec, Krzysztof

    2010-01-01

    Polyurethane cationomers were synthesised in the reaction of 4,4’-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium th...

  20. Synthesis, Surface Modification and Characterisation of Biocompatible Magnetic Iron Oxide Nanoparticles for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Mohamad Zaki Ab Rahman

    2013-06-01

    Full Text Available Superparamagnetic iron oxide nanoparticles (MNPs with appropriate surface chemistry exhibit many interesting properties that can be exploited in a variety of biomedical applications such as magnetic resonance imaging contrast enhancement, tissue repair, hyperthermia, drug delivery and in cell separation. These applications required that the MNPs such as iron oxide Fe3O4 magnetic nanoparticles (Fe3O4 MNPs having high magnetization values and particle size smaller than 100 nm. This paper reports the experimental detail for preparation of monodisperse oleic acid (OA-coated Fe3O4 MNPs by chemical co-precipitation method to determine the optimum pH, initial temperature and stirring speed in order to obtain the MNPs with small particle size and size distribution that is needed for biomedical applications. The obtained nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray fluorescence spectrometry (EDXRF, thermogravimetric analysis (TGA, X-ray powder diffraction (XRD, and vibrating sample magnetometer (VSM. The results show that the particle size as well as the magnetization of the MNPs was very much dependent on pH, initial temperature of Fe2+ and Fe3+ solutions and steering speed. The monodisperse Fe3O4 MNPs coated with oleic acid with size of 7.8 ± 1.9 nm were successfully prepared at optimum pH 11, initial temperature of 45 °C and at stirring rate of 800 rpm. FTIR and XRD data reveal that the oleic acid molecules were adsorbed on the magnetic nanoparticles by chemisorption. Analyses of TEM show the oleic acid provided the Fe3O4 particles with better dispersibility. The synthesized Fe3O4 nanoparticles exhibited superparamagnetic behavior and the saturation magnetization of the Fe3O4 nanoparticles increased with the particle size.

  1. Differential diagnosis in patients with suspected bile acid synthesis defects

    Institute of Scientific and Technical Information of China (English)

    Dorothea Haas; Hongying Gan-Schreier; Claus-Dieter Langhans; Tilman Rohrer; Guido Engelmann; Maura Heverin; David W Russell

    2012-01-01

    AIM:To investigate the clinical presentations associated with bile acid synthesis defects and to describe identification of individual disorders and diagnostic pitfalls.METHODS:Authors describe semiquantitative determination of 16 urinary bile acid metabolites by electrospray ionization-tandem mass spectrometry.Sample preparation was performed by solid-phase extraction.The total analysis time was 2 min per sample.Authors determined bile acid metabolites in 363 patients with suspected defects in bile acid metabolism.RESULTS:Abnormal bile acid metabolites were found in 36 patients.Two patients had bile acid synthesis defects but presented with atypical presentations.In 2 other patients who were later shown to be affected by biliary atresia and cystic fibrosis the profile of bile acid metabolites was initially suggestive of a bile acid synthesis defect.Three adult patients suffered from cerebrotendinous xanthomatosis.Nineteen patients had peroxisomal disorders,and 10 patients had cholestatic hepatopathy of other cause.CONCLUSION:Screening for urinary cholanoids should be done in every infant with cholestatic hepatopathy as well as in children with progressive neurological disease to provide specific therapy.

  2. Synthesis of new fatty acids amides from aminolysis of fatty acid methyl esters (FAMEs)

    International Nuclear Information System (INIS)

    Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce cytotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs). (author)

  3. Preliminary results for preparation and characterisation of immobilised humic acid on silicon wafer

    International Nuclear Information System (INIS)

    To facilitate understanding the chemistry of the interactions of radionuclides with humic acid (HA) in microscopic scale, we have immobilized humic acid on silicon wafers. In this communication, we present a simple protocol to immobilise humic acid on silicon wafer surface. A trifunctional silane reagent 3-aminopropyltrimethoxysilane (APTES) was used to modify the surface of silicon wafers and appeared to be able to strongly attached soluble humic acid through their carboxylic groups to solid support. Humic acid, anchored in a following incubation step, were proved to be able to bind Am(III). (orig.)

  4. Characterisation of traditional Macedonian edible oils by their fatty acid composition and their volatile compounds

    OpenAIRE

    Ivanova, Violeta; Mitrev, Sasa; Stafilov, Trajče; Markova Ruzdik, Natalija; Leitner, Erich; Lankmayr, Ernst; Siegmund, Barbara

    2015-01-01

    The fatty acid composition and volatile compounds of selected traditional Macedonian edible oils of several varieties, including sunflower seeds, pumpkin seeds, flax seed, rapeseed and sesame seeds, were analysed. The fatty acid (FA) composition was determined by GC-FID analysis after transesterification into the corresponding methyl esters. α-Linolenic acid (C18:3) was the main unsaturated fatty acid in flax seed oil (56.2% of total FA), oleic acid (C18:1) dominated in rapeseed and sesame se...

  5. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    Institute of Scientific and Technical Information of China (English)

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao

    2005-01-01

    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  6. Synthesis, structural characterisation and antibacterial activity of Ag+-doped fluorapatite nanomaterials prepared by neutralization method

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The neutralization method has been used for synthesis of silver-doped fluorapatite powders. • Particles of silver-doped fluorapatite samples are of nano size and homogenous in composition. • The Ag+-doped fluorapatite samples showed antibacterial effect against Kllebsiela pneumoniae, Staphylococcus aureus and Micrococcus luteus. • AFM studies showed that silver-doped sample causes considerable morphological changes of tested bacterial cells. - Abstract: Silver doped fluorapatite nanopowders were synthesised by neutralization method, which consists of dissolving Ag2O in solution of HF and H3PO4 and addition to suspension of Ca(OH)2. The powder XRD, SEM and FTIR studies indicated the formation of a fluorapatite nanomaterials with average length of the particles is about 80 nm and a width of about 15 nm. The FTIR studies show that carbonate content in samples is very small and carbonte ions substitute both phosphate and hydroxyl groups in the crystal structure of samples, forming AB-type fluorapatite. Antibacterial studies have demonstrated that all Ag+-doped fluorapatite samples exhibit bactericidal effect against pathogens: Staphylococcus aureus, Micrococcus luteus and Kllebsiela pneumoniae. Antibacterial activity increased with the increase of Ag+ in the samples. The atomic force microscopy studies revealed extensive damage to the bacterial cell envelops in the presence of Ag+-doped fluorapatite particles which may lead to their death. The synthesized Ag+-doped fluorapatite nanomaterials are promising as antibacterial biomaterials in orthopedics and dentistry

  7. Synthesis of Uncarbonised Coconut Shell Nanoparticles: Characterisation and Particle Size Determination

    Directory of Open Access Journals (Sweden)

    S.A. Bello

    2015-06-01

    Full Text Available The possibility of using mechanical milling for the synthesis of uncarbonised coconut shell nanoparticles (UCSNPs has been investigated. UCSNPs were synthesized from discarded coconut shells (CSs using top down approach. The sundried CSs were crushed, ground and then sieved using hammer crusher, a two disc grinder and set of sieves with shine shaker respectively. The CS powders retained in the pan below 37 µm sized sieve were milled for 70 hours to obtain UCSNPS. Samples for analysis were taken at 16 and 70 hours. UCSNPs were analyzed using transmission electron microscope (TEM, scanning electron microscope (SEM with attached EDS and Gwyddion software. Samples of UCSNPs obtained at 16 and 70hours show that the deep brown colour of the initial CS powder became fading as the milling hour increased. The size determination from TEM image revealed spherical particles with an average size of 18.23 nm for UCSNPs obtained at 70 hour milling. The EDS spectrographs revealed an increase in the carbon counts with increased milling hours. This is attributable to dryness of the CS powders by the heat generated during the milling process due to absorption of kinetic energy by the CS powders from the milling balls. SEM micrographs revealed UCSNPs in agglomerated networks. The SEM micrograph/Gyweddion particles size determination showed average particles of 170.5 ±3 and 104.9 ±4.1 nm for UCSNPs obtained at 16 and 70 hours respectively. Therefore, production of UCSNPs through mechanical milling using mixture of ceramic balls of different sizes has been established especially when the particles of the sourced/initial CS powders falls below 37 µm.

  8. Lipase-catalyzed synthesis of fatty acid amide (erucamide) using fatty acid and urea.

    Science.gov (United States)

    Awasthi, Neeraj Praphulla; Singh, R P

    2007-01-01

    Ammonolysis of fatty acids to the corresponding fatty acid amides is efficiently catalysed by Candida antartica lipase (Novozym 435). In the present paper lipase-catalysed synthesis of erucamide by ammonolysis of erucic acid and urea in organic solvent medium was studied and optimal conditions for fatty amides synthesis were established. In this process erucic acid gave 88.74 % pure erucamide after 48 hour and 250 rpm at 60 degrees C with 1:4 molar ratio of erucic acid and urea, the organic solvent media is 50 ml tert-butyl alcohol (2-methyl-2-propanol). This process for synthesis is economical as we used urea in place of ammonia or other amidation reactant at atmospheric pressure. The amount of catalyst used is 3 %.

  9. Acetylsalicylic acid: Incoming 150 years of the first synthesis

    Directory of Open Access Journals (Sweden)

    Mijin Dušan Ž.

    2002-01-01

    Full Text Available Acetylsalicylic acid is one of the most fascinating and versatile drugs known to medicine, as well as one of the oldest. Acetylsalicylic acid is a drug which is safe, with analgetic, antirheumatic, anti-inflammatory antiplatelet and antithrombotic action. It may be applied not only in clinical practice, but also as prevention. The first known use of an acetylsalicylic acid-like preparation can be traced to ancient Greece. In 1853 Charles Gerhardt published the first synthesis of acetylsalicylic acid. Felix Hoffmann, a chemist for Friedrich Bayer, a German dye company obtained a patent on acetylsalicylic acid some 40 years later. Bayer coined the name Aspirin for the new product. The 20 in century was the century in which many researchers in many companies tried to improve the synthesis of acetylsalicylic acid not only in terms of yield but also purity. This paper describes the history, use, mechanism of action, synthesis and production as well as the purification and stability of acetylsalicylic acid.

  10. Synthesis, characterisation and antioxidant activity of luteolin-vanadium(II) complex.

    Science.gov (United States)

    Roy, Souvik; Mallick, Sougata; Chakraborty, Tania; Ghosh, Nilanjan; Singh, Amit Kumar; Manna, Subhadip; Majumdar, Sumana

    2015-04-15

    The complex formation between luteolin (L) and vanadium(IV) oxide sulphate monohydrate (VOSO4·H2O) was examined under UV-visible, infra-red spectroscopy, mass spectroscopy and NMR techniques. The spectroscopic data indicated that luteolin reacts with vanadium oxide cation (VO(+2)) through 4-carbonyl-5-hydroxy chelation site in the two luteolin molecule. The free radical antioxidant activity of the complex with respect to the parent molecule was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azinobis 3-ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS) methods. It was observed that the free radical scavenging activity and ferric ion reducing potential of luteolin was increased after the formation of complex with vanadium oxide (VO(+2)) cation.

  11. Phosphorus promotion and poisoning in zeolite-based materials: synthesis, characterisation and catalysis.

    Science.gov (United States)

    van der Bij, Hendrik E; Weckhuysen, Bert M

    2015-10-21

    Phosphorus and microporous aluminosilicates, better known as zeolites, have a unique but poorly understood relationship. For example, phosphatation of the industrially important zeolite H-ZSM-5 is a well-known, relatively inexpensive and seemingly straightforward post-synthetic modification applied by the chemical industry not only to alter its hydrothermal stability and acidity, but also to increase its selectivity towards light olefins in hydrocarbon catalysis. On the other hand, phosphorus poisoning of zeolite-based catalysts, which are used for removing nitrogen oxides from exhaust fuels, poses a problem for their use in diesel engine catalysts. Despite the wide impact of phosphorus-zeolite chemistry, the exact physicochemical processes that take place require a more profound understanding. This review article provides the reader with a comprehensive and state-of-the-art overview of the academic literature, from the first reports in the late 1970s until the most recent studies. In the first part an in-depth analysis is undertaken, which will reveal universal physicochemical and structural effects of phosphorus-zeolite chemistry on the framework structure, accessibility, and strength of acid sites. The second part discusses the hydrothermal stability of zeolites and clarifies the promotional role that phosphorus plays. The third part of the review paper links the structural and physicochemical effects of phosphorus on zeolite materials with their catalytic performance in a variety of catalytic processes, including alkylation of aromatics, catalytic cracking, methanol-to-hydrocarbon processing, dehydration of bioalcohol, and ammonia selective catalytic reduction (SCR) of NOx. Based on these insights, we discuss potential applications and important directions for further research.

  12. Characterisation of antioxidant and antiproliferative acidic polysaccharides from Chinese wolfberry fruits

    NARCIS (Netherlands)

    He, N.W.; Yang, X.B.; Jiao, Y.D.; Tian, L.; Zhao, Y.

    2012-01-01

    Wolfberry fruit polysaccharides (WFPs) were isolated by hot-water extraction and ethanol precipitation. With HPLC analysis, WFPs were for the first time identified as acidic polysaccharides with galacturonic acid being the main component monosaccharide (24.9%), followed by galactose (21.3%), arabino

  13. Characterisation of a 1,4-ß-fucoside hydrolase degrading colanic acid

    NARCIS (Netherlands)

    Verhoef, R.P.; Beldman, G.; Schols, H.A.; Siika-aho, M.; Ratto, M.; Buchert, J.; Voragen, A.G.J.

    2005-01-01

    A novel colanic acid-degrading enzyme was isolated from a mixed culture filtrate obtained by enrichment culturing of a compost sample using colanic acid as carbon source. The enzyme was partially purified resulting in a 17-fold increase in specific activity. Further purification by Native PAGE revea

  14. Composite polyester membranes with embedded dendrimer hosts and bimetallic Fe/Ni nanoparticles: synthesis, characterisation and application to water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Malinga, S. P., E-mail: sitholespr@yahoo.com; Arotiba, O. A. [University of Johannesburg, Department of Applied Chemistry (South Africa); Krause, R. W. M. [Rhodes University, Department of Chemistry (South Africa); Mapolie, S. F. [University of Stellenbosch, Department of Chemistry and Polymer Science (South Africa); Diallo, M. S. [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST) (Korea, Republic of); Mamba, B. B., E-mail: bmamba@uj.ac.za [University of Johannesburg, Department of Applied Chemistry (South Africa)

    2013-06-15

    This study describes the preparation, characterization and evaluation of new composite membranes with embedded dendrimer hosts and Fe/Ni nanoparticles. These new reactive membranes consist of films of cyclodextrin-poly(propyleneimine) dendrimers ({beta}-CD-PPI) that are deposited onto commercial polysulfone microporous supports and crosslinked with trimesoyl chloride (TMC). The membranes were subsequently loaded with Fe/Ni nanoparticles and evaluated as separation/reactive media in aqueous solutions using 2,4,6-trichlorophenol as model pollutant. The morphology and physicochemical properties of the composite membranes were characterised using high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy and measurements of contact angle, water intake, porosity and water permeability. The sorption capacity and catalytic activity of the membranes were evaluated using ion chromatography, atmospheric pressure chemical ionisation-mass spectrometry and UV-Vis spectroscopy (UV-Vis). The sizes of the embedded Fe/Ni nanoparticles in the membranes ranged from 40 to 66 nm as confirmed by HR-TEM. The reaction rates for the dechlorination of 2,4,6-trichlorophenol ranged from 0.00148 to 0.00250 min{sup -1}. In all cases, we found that the reaction by-products consisted of chloride ions and mixtures of compounds including phenol (m/z = 93), 2,4-dichlorophenol (m/z = 163) and 4-chlorophenol (m/z = 128). The overall results of this study suggest that {beta}-CD-PPI dendrimers are promising building blocks for the synthesis of composite and reactive membranes for the efficient removal of chlorinated organic pollutants from water.

  15. Design and Synthesis of Novel Peptide Nucleic Acid Monomers

    Institute of Scientific and Technical Information of China (English)

    白金泉; 李英; 刘克良

    2001-01-01

    All of the four nucleobases in DNA have replaced the 4-hydroxy group of N-[2-(tert-butoxycarbonylaminomethyl)-trams-4-hydroxy]tetrahydropyrrole acetic acid methyl ester with cis-stereochemistry. An efficient route for the synthesis of N-[2-(tert-butoxycarbonylaminomethyl)-trans-4-hydroxy]-tetrahydropyrrole acetic acid methyl ester has been developed.Starting with this intermediate, the protected monmers were synthesized by the Mitsunobu reaction or via its tosylate.

  16. Methane-to-acetic acid synthesis matriculates at Penn State

    Energy Technology Data Exchange (ETDEWEB)

    Rotman, D.

    1994-04-20

    Direct conversion of methane to commercially valuable chemicals remains one of the grails of industrial chemistry. But scientists at Pennsylvania State University (University Park) appear to have made a significant step forward, reporting the direct catalytic conversion of methane into acetic acid under relatively mild conditions. Commercial acetic production involves a three-step process, including steam reforming of methane to synthesis gas (syngas) and the carbonylation of methanol of acetic acid.

  17. Stereoselective synthesis of unsaturated α-amino acids.

    Science.gov (United States)

    Fanelli, Roberto; Jeanne-Julien, Louis; René, Adeline; Martinez, Jean; Cavelier, Florine

    2015-06-01

    Stereoselective synthesis of unsaturated α-amino acids was performed by asymmetric alkylation. Two methods were investigated and their enantiomeric excess measured and compared. The first route consisted of an enantioselective approach induced by the Corey-Lygo catalyst under chiral phase transfer conditions while the second one involved the hydroxypinanone chiral auxiliary, both implicating Schiff bases as substrate. In all cases, the use of a prochiral Schiff base gave higher enantiomeric excess and yield in the final desired amino acid.

  18. The Use of Supported Acidic Ionic Liquids in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Rita Skoda-Földes

    2014-06-01

    Full Text Available Catalysts obtained by the immobilisation of acidic ionic liquids (ILs on solid supports offer several advantages compared to the use of catalytically active ILs themselves. Immobilisation may result in an increase in the number of accessible active sites of the catalyst and a reduction of the amount of the IL required. The ionic liquid films on the carrier surfaces provide a homogeneous environment for catalytic reactions but the catalyst appears macroscopically as a dry solid, so it can simply be separated from the reaction mixture. As another advantage, it can easily be applied in a continuous fixed bed reactor. In the present review the main synthetic strategies towards the preparation of supported Lewis acidic and Brønsted acidic ILs are summarised. The most important characterisation methods and structural features of the supported ionic liquids are presented. Their efficiency in catalytic reactions is discussed with special emphasis on their recyclability.

  19. Genetics Home Reference: congenital bile acid synthesis defect type 1

    Science.gov (United States)

    ... 88(4):1833-41. Citation on PubMed Clayton PT. Disorders of bile acid synthesis. J Inherit Metab ... 13. Review. Citation on PubMed Subramaniam P, Clayton PT, Portmann BC, Mieli-Vergani G, Hadzić N. Variable ...

  20. One-Pot Synthesis of N-Phosphoryl Amino Acids

    Institute of Scientific and Technical Information of China (English)

    GUO Xin; FU Hua; LIN Chang-Xue; ZHAO Yu-Fen

    2003-01-01

    @@ Phosphoramidates have been considered as an important class of rationally designed therapeutics especially asoligonucleotide analogs employed as antisene and antigene agents. [1] N-Phosphoryl amino acids are of biological andpharmaceutical interest, [2] and can be used as the building blocks in synthesis of polypeptides. [3

  1. Characterisation of calamansi (Citrus microcarpa). Part I: volatiles, aromatic profiles and phenolic acids in the peel.

    Science.gov (United States)

    Cheong, Mun Wai; Chong, Zhi Soon; Liu, Shao Quan; Zhou, Weibiao; Curran, Philip; Bin Yu

    2012-09-15

    Volatile compounds in the peel of calamansi (Citrus microcarpa) from Malaysia, the Philippines and Vietnam were extracted with dichloromethane and hexane, and then analysed by gas chromatography-mass spectroscopy/flame ionisation detector. Seventy-nine compounds representing >98% of the volatiles were identified. Across the three geographical sources, a relatively small proportion of potent oxygenated compounds was significantly different, exemplified by the highest amount of methyl N-methylanthranilate in Malaysian calamansi peel. Principal component analysis and canonical discriminant analysis were applied to interpret the complex volatile compounds in the calamansi peel extracts, and to verify the discrimination among the different origins. In addition, four common hydroxycinnamic acids (caffeic, p-coumaric, ferulic and sinapic acids) were determined in the methanolic extracts of calamansi peel using ultra-fast liquid chromatography coupled to photodiode array detector. The Philippines calamansi peel contained the highest amount of total phenolic acids. In addition, p-Coumaric acid was the dominant free phenolic acids, whereas ferulic acid was the main bound phenolic acid. PMID:23107679

  2. Characterisation of calamansi (Citrus microcarpa). Part I: volatiles, aromatic profiles and phenolic acids in the peel.

    Science.gov (United States)

    Cheong, Mun Wai; Chong, Zhi Soon; Liu, Shao Quan; Zhou, Weibiao; Curran, Philip; Bin Yu

    2012-09-15

    Volatile compounds in the peel of calamansi (Citrus microcarpa) from Malaysia, the Philippines and Vietnam were extracted with dichloromethane and hexane, and then analysed by gas chromatography-mass spectroscopy/flame ionisation detector. Seventy-nine compounds representing >98% of the volatiles were identified. Across the three geographical sources, a relatively small proportion of potent oxygenated compounds was significantly different, exemplified by the highest amount of methyl N-methylanthranilate in Malaysian calamansi peel. Principal component analysis and canonical discriminant analysis were applied to interpret the complex volatile compounds in the calamansi peel extracts, and to verify the discrimination among the different origins. In addition, four common hydroxycinnamic acids (caffeic, p-coumaric, ferulic and sinapic acids) were determined in the methanolic extracts of calamansi peel using ultra-fast liquid chromatography coupled to photodiode array detector. The Philippines calamansi peel contained the highest amount of total phenolic acids. In addition, p-Coumaric acid was the dominant free phenolic acids, whereas ferulic acid was the main bound phenolic acid.

  3. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    Directory of Open Access Journals (Sweden)

    Enrico Prenesti

    2012-01-01

    Full Text Available A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria. Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture, ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing.

  4. Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments.

    Science.gov (United States)

    Król, Bożena; Król, Piotr; Pikus, Stanisław; Chmielarz, Paweł; Skrzypiec, Krzysztof

    2010-08-01

    Polyurethane cationomers were synthesised in the reaction of 4,4'-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. (1)H, (13)C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on (1)H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss-Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m(2). That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions. PMID:20927181

  5. Molecular and Functional Characterisation of a new Mammalian Family of Proton-coupled Amino Acid Transporters

    OpenAIRE

    Foltz, Martin

    2006-01-01

    Proton-coupled amino acid transport (PAT) systems in the apical membrane of epithelial cells of the small intestine and the renal tubule have been demonstrated by use of the human intestinal cell line Caco-2 and renal brush border membrane vesicles. The present thesis summarises the revelation of the molecular entity of the PAT system and provides deeper insights into this new mammalian family of proton/amino acid cotransporters. The identified family comprises four structural similar murine ...

  6. Characterisation of films and nanopaper obtained from cellulose synthesised by acetic acid bacteria.

    Science.gov (United States)

    Rozenberga, Linda; Skute, Marite; Belkova, Lubova; Sable, Inese; Vikele, Laura; Semjonovs, Pavels; Saka, Madara; Ruklisha, Maija; Paegle, Longina

    2016-06-25

    Bacterial cellulose (BC) samples were obtained using two culture media (glucose and glucose+fructose) and two bacteria (Komagataeibacter rhaeticus and Komagataeibacter hansenii). Nanopaper was obtained from the BC through oxidation and both were studied to determine the impact of culture media and bacteria strain on nanofiber structure and mechanical properties. AFM and SEM were used to investigate fibre dimensions and network morphology; FTIR and XRD to determine cellulose purity and crystallinity; carboxyl content, degree of polymerisation and zeta potential were used to characterise nanofibers. Tensile testing showed that nanopaper has up to 24 times higher Young's modulus (7.39GPa) than BC (0.3GPa). BC displayed high water retention values (86-95%) and a degree of polymerisation up to 2540. Nanofibers obtained were 80-120nm wide and 600-1200nm long with up to 15% higher crystallinity than the original BC. It was concluded that BC is an excellent source for easily obtainable, highly crystalline and strong nanofibers. PMID:27083790

  7. Stereoselective synthesis of stable-isotope-labeled amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

    1994-12-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

  8. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    Directory of Open Access Journals (Sweden)

    Akiyoshi Hoshino

    2009-06-01

    Full Text Available Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1 system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source and keto acids (oxylic acid sources. In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.

  9. Photolabile linker for the synthesis of hydroxamic acids

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to a photolabile hydroxamate linker based on the o - nitroveratryl group and its application for multistep solid-phase synthesis and controlled photolytic release of hydroxamic acids. The invention provides a method for producing a solid support comprising...... a hydroxylamine - functionalized photolabile linker, and the so produced hydroxylamine - functionalized photolabile solid support. The invention further provides a method for synthesizing a one-bead-one compound library of hydroxamic acid derivatives on a photolabile linker, as well as a method for screening...... a library of hydroxamic acid derivatives....

  10. Synthesis and Characterization of Fatty Acid/Amino Acid Self-Assemblies

    OpenAIRE

    Gajowy, Joanna; Bolikal, Durgadas; Kohn, Joachim; El Fray, Miroslawa

    2014-01-01

    In this paper, we discuss the synthesis and self-assembling behavior of new copolymers derived from fatty acid/amino acid components, namely dimers of linoleic acid (DLA) and tyrosine derived diphenols containing alkyl ester pendent chains, designated as “R” (DTR). Specific pendent chains were ethyl (E) and hexyl (H). These poly(aliphatic/aromatic-ester-amide)s were further reacted with poly(ethylene glycol) (PEG) and poly(ethylene glycol methyl ether) of different molecular masses, thus resu...

  11. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Science.gov (United States)

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

    2016-01-18

    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues. PMID:26572799

  12. Lactide Synthesis and Chirality Control for Polylactic acid Production.

    Science.gov (United States)

    Van Wouwe, Pieter; Dusselier, Michiel; Vanleeuw, Evelien; Sels, Bert

    2016-05-10

    Polylactic acid (PLA) is a very promising biodegradable, renewable, and biocompatible polymer. Aside from its production, its application field is also increasing, with use not only in commodity applications but also as durables and in biomedicine. In the current PLA production scheme, the most expensive part is not the polymerization itself but obtaining the building blocks lactic acid (LA) and lactide, the actual cyclic monomer for polymerization. Although the synthesis of LA and the polymerization have been studied systematically, reports of lactide synthesis are scarce. Most lactide synthesis methods are described in patent literature, and current energy-intensive, aselective industrial processes are based on archaic scientific literature. This Review, therefore, highlights new methods with a technical comparison and description of the different approaches. Water-removal methodologies are compared, as this is a crucial factor in PLA production. Apart from the synthesis of lactide, this Review also emphasizes the use of chemically produced racemic lactic acid (esters) as a starting point in the PLA production scheme. Stereochemically tailored PLA can be produced according to such a strategy, giving access to various polymer properties.

  13. The optimisation study of tbp synthesis process by phosphoric acid

    International Nuclear Information System (INIS)

    The present work deals with the optimisation study of TBP synthesis process by phosphoric acid. This way of synthesis is more advantageous than POCL3 or P2O5 as phosphatant agents. these latters are toxic and dangerous for the environnement. The optimisation study is based on a series of 16 experiences taking into account the range of variation of the following parameters : temperature, pressure, reagents mole ratio, promoter content. the yield calculation is based on the randomisation of an equation including all parameters. the resolution of this equation gave a 30% TBP molar ratio. this value is in agreement with that of experimental data

  14. Characterisation of Non-Autoinducing Tropodithietic Acid (TDA) Production from Marine Sponge Pseudovibrio Species

    DEFF Research Database (Denmark)

    Harrington, Catriona; Reen, F. Jerry; Mooij, Marlies J.;

    2014-01-01

    is the antibacterial compound tropodithietic acid (TDA). The aim of this study was to provide insight into the bioactivity of and the factors governing the production of TDA in marine Pseudovibrio isolates from a collection of marine sponges. The TDA produced by these Pseudovibrio isolates exhibited potent...

  15. Physio-chemical, microbiological properties of tempoyak and molecular characterisation of lactic acid bacteria isolated from tempoyak.

    Science.gov (United States)

    Chuah, Li-Oon; Shamila-Syuhada, Ahamed Kamal; Liong, Min Tze; Rosma, Ahmad; Thong, Kwai Lin; Rusul, Gulam

    2016-09-01

    This study aims to determine physio-chemical properties of tempoyak, characterise the various indigenous species of lactic acid bacteria (LAB) present at different stages of fermentation and also to determine the survival of selected foodborne pathogens in tempoyak. The predominant microorganisms present in tempoyak were LAB (8.88-10.42 log CFU/g). Fructobacillus durionis and Lactobacillus plantarum were the dominant members of LAB. Other LAB species detected for the first time in tempoyak were a fructophilic strain of Lactobacillus fructivorans, Leuconostoc dextranicum, Lactobacillus collinoides and Lactobacillus paracasei. Heterofermentative Leuconostoc mesenteroides and F. durionis were predominant in the initial stage of fermentation, and as fermentation proceeded, F. durionis remained predominant, but towards the end of fermentation, homofermentative Lb. plantarum became the predominant species. Lactic, acetic and propionic acids were present in concentrations ranging from 0.30 to 9.65, 0.51 to 7.14 and 3.90 to 7.31 mg/g, respectively. Genotyping showed a high degree of diversity among F. durionis and Lb. plantarum isolates, suggesting different sources of LAB. All tested Lb. plantarum and F. durionis (except for one isolate) isolates were multidrug resistant. Salmonella spp., Listeria monocytogenes and Staphylococcus aureus were not detected. However, survival study showed that these pathogens could survive up to 8-12 days. The results aiming at improving the quality and safety of tempoyak. PMID:27217364

  16. Synthesis of isothiocyanate-derived mercapturic acids

    NARCIS (Netherlands)

    Vermeulen, M.; Zwanenburg, B.; Chittenden, G.J.F.; Verhagen, H.

    2003-01-01

    Twelve mercapturic acids derived from saturated and unsaturated aliphatic and aromatic isothiocyanates were synthesised, by adding isothiocyanate to a solution of N-acetyl-L-cysteine and sodium bicarbonate, in a typical yield of 77%. Isothiocyanates were synthesised first by adding the corresponding

  17. Characterisation of solution cast cellulose nanofibre – reinforced poly(lactic acid

    Directory of Open Access Journals (Sweden)

    2010-01-01

    Full Text Available Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Composite films containing 2.5 and 5.0 wt% flax cellulose (FC fibres were prepared by solution casting of mixtures of poly(lactic acid (PLA solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solution cast pure PLA film, with thickness of around 160 m, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.

  18. Surface characterisation of ethylene-propylene-diene rubber upon exposure to aqueous acidic solution

    DEFF Research Database (Denmark)

    Mitra, S.; Ghanbari-Siahkali, Afshin; Kingshott, P.;

    2006-01-01

    but significantly different with respect to molar mass and the presence of long chain branching. Both rubbers contained 5-ethylidene-2-norbomene (ENB) as diene. Solution cast films of pure EPDM samples were exposed in two different acidic solutions, viz. chromosulphuric (Cr (VI)/H2SO4) and sulphuric acid (H2SO4....... Furthermore, 20% Cr (VI)/H2SO4 also attacked the allylic carbon-hydrogen (C-H) bonds of ENB resulting in more oxygenated species on the surface compared to 20% H2SO4 under identical conditions. Cr (VI) in the 20% Cr (VI)/H2SO4 was found to play an important role in alteration of surface chemistry. Studies...

  19. Monoclonal antibodies targeted to alpha-oligonucleotides. Characterisation and application in nucleic acid detection.

    OpenAIRE

    Cros, P.; Kurfürst, R; Allibert, P; Battail, N; Piga, N; Roig, V; Thuong, N T; Mandrand, B; Hélène, C

    1994-01-01

    The aim of the present study was to test the antigenicity of alpha-deoxyribonucleotides in order to develop a new tool for the detection of nucleic acid sequences for use in diagnostic applications. We describe four monoclonal antibodies (Mabs) which recognize alpha-deoxyribonucleotides. Two were raised against a poly(alpha-dT) sequence and specifically recognized the alpha-dT nucleotide. Two were raised against a sequence containing all four common nucleotides as alpha-nucleotides and, surpr...

  20. Zeolite deactivation during hydrocarbon reactions: characterisation of coke precursors and acidity, product distribution

    OpenAIRE

    Wang, B.

    2008-01-01

    The catalytic conversion of hydrocarbons over zeolites has been applied in large scale petroleum-refining processes. However, there is always formation and retention of heavy by-products, called coke, which causes catalyst deactivation. This deactivation is due to the poisoning of the acid sites and/or pore blockage. The formation of coke on hydrocarbon processing catalysts is of considerable technological and economic importance and a great deal of work has been carried out to this study. Th...

  1. Extremely acidic mine lake ecosystems in Lusatia (Germany) : characterisation and development of sustainable, biology-based acidity removal technologies

    Energy Technology Data Exchange (ETDEWEB)

    Fyson, A. [Brandenburg Univ. of Technology, Cottbus, (Germany)]|[Inst. of Freshwater Ecology and Inland Fisheries, Berlin (Germany); Deneke, R.; Nixdorf, B. [Brandenburg Univ. of Technology, Cottbus, (Germany); Steinberg, C.E.W. [Inst. of Freshwater Ecology and Inland Fisheries, Berlin (Germany)

    2003-07-01

    There are approximately 500 infilled open-cast lignite pits in Germany that are extremely acidic because of high concentrations of dissolved metals, mostly iron and aluminium. The mining lakes have pH values of 2.4 to 3.4 and also have high sulphate concentrations. Efforts are being made to neutralize the lakes for recreational purposes. The acidity can be removed from the lakes in an economical and environmentally sustainable manner by flooding through diversion of neutral, nutrient-rich river water. This paper described the living conditions of the acidic mining lakes in the Lausitz region of Germany and summarized the benefits of the controlled eutrophication approach to enhance natural, self-sustaining processes for acid neutralization. Compared to infilling with river water, eutrophication increases lake productivity and removes acidity through sediment bound and water column biologically-mediated processes. The study involved basic research on particle transport in streams and lakes, pelagic food web interactions and submerged macrophyte metabolism. It also looked at the role of wetlands, bacterial interactions at the water-sediment interface, and modelling. It was shown that the addition of phosphorus and carbon to the water column can enhance primary production. Future studies will examine environmentally acceptable treatment strategies that offer an alternative to chemical treatment. 20 refs., 1 tab., 2 figs.

  2. Extremely acidic mine lake ecosystems in Lusatia (Germany) : characterisation and development of sustainable, biology-based acidity removal technologies

    International Nuclear Information System (INIS)

    There are approximately 500 infilled open-cast lignite pits in Germany that are extremely acidic because of high concentrations of dissolved metals, mostly iron and aluminium. The mining lakes have pH values of 2.4 to 3.4 and also have high sulphate concentrations. Efforts are being made to neutralize the lakes for recreational purposes. The acidity can be removed from the lakes in an economical and environmentally sustainable manner by flooding through diversion of neutral, nutrient-rich river water. This paper described the living conditions of the acidic mining lakes in the Lausitz region of Germany and summarized the benefits of the controlled eutrophication approach to enhance natural, self-sustaining processes for acid neutralization. Compared to infilling with river water, eutrophication increases lake productivity and removes acidity through sediment bound and water column biologically-mediated processes. The study involved basic research on particle transport in streams and lakes, pelagic food web interactions and submerged macrophyte metabolism. It also looked at the role of wetlands, bacterial interactions at the water-sediment interface, and modelling. It was shown that the addition of phosphorus and carbon to the water column can enhance primary production. Future studies will examine environmentally acceptable treatment strategies that offer an alternative to chemical treatment. 20 refs., 1 tab., 2 figs

  3. Synthesis of Chiral Amino Cyclic Phosphoric Acids

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Chirai amino cyclic phosphoric acids, 5-amino-2-hydroxy-4- (4-nitrophenyl)-l, 3,2-dioxaphospho- rinane 2-oxide and 2-hydroxy-4- (4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64. 2% and 72. 8% respectively) from 2-amino-l-aryl-l,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.

  4. Fatty acid effects on fibroblast cholesterol synthesis

    International Nuclear Information System (INIS)

    Two cell lines of normal (CRL 1475, GM5565) and of familial hypercholesterolemia (FH) (CM 486,488) fibroblasts were preincubated with medium containing the growth factor ITS, 2.5 mg/ml fatty acid-free BSA, or 35.2 μmol/ml of these fatty acids complexed with 2.5 mg BSA/ml: stearic (18:0), caprylic (8:0), oleic (18:1;9), linoleic (18:2;9,12), linolenic (18:3;9,12,15), docosahexaenoic (22:6;4,7,10,13,16,19)(DHA) or eicosapentaenoic (20:5;5,8,11,14,17)(EPA). After 20 h, cells were incubated for 2 h with 0.2 μCi [14C]acetate/ml. Cells were hydrolyzed; an aliquot was quantitated for radioactivity and protein. After saponification and extraction with hexane, radioactivity in the aqueous and organic phases was determined. The FH cells always incorporated 30-90% more acetate/mg protein than normal cells but the pattern of the fatty acid effects was similar in both types. When the values were normalized to 1 for the BSA-only group, cells with ITS had the greatest [14C]acetate incorporation (1.45) followed by the caprylic group (1.14). Cells incubated with 18:3, 20:6 or 22:6 incorporated about the same amount as BSA-only. Those preincubated with 18:2, 18:1, 18:0 showed the least acetate incorporation (0.87, 0.59 and 0.52, respectively). The percentage of total 14C counts which extracted into hexane was much greater in FH cells; however, these values varied with the fatty acid, e.g., 1.31(18:0) and 0.84(8:0) relative to 1

  5. Characterisation by Moessbauer Spectroscopy of the Forms of Iron in Sulfide-Rich Fulvic Acid Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, B. A., E-mail: bgoodm@scri.sari.ac.uk [Scottish Crop Research Institute, Invergowrie (United Kingdom); Cheshire, M. V. [Macaulay Land Use Research Institute, Craigiebuckler (United Kingdom)

    2002-09-15

    Variations in the nature of the bonding between iron and fulvic acid as a function of pH in sulfide-rich solutions have been investigated by {sup 57}Fe Moessbauer spectroscopy. In all solutions iron was enriched to 95% in the {sup 57}Fe isotope and ratios of Fe : fulvic acid were maintained at 1 : 100 on a weight basis for all measurements. When the pH was decreased below 5.0, there was a progressive change in the composition of the spectra, which contained three distinct components that were similar to those seen in the absence of sulfide; i.e., a sextet from magnetically-dilute Fe(III) and doublets from Fe(II) and Fe(III). There was, however, a higher proportion of the iron as Fe(II) in the sulfide-containing solutions and this represented the only form of iron at very low pH. Establishment of equilibria was slow as evidenced by considerable hysteresis between the compositions of the solutions with decreasing and increasing pHs. On increasing the pH, sulfide prevented the formation of magnetically dilute Fe(III) species and instead, in the range 3.5-6.0, compounds were generated with parameters consistent with sulfur being coordinated to the iron. One had parameters similar to those of pyrite and hence probably contains disulfide (S{sub 2}{sup 2-}) units, whilst a second, with poorly defined magnetic hyperfine splitting, may contain monosulfide (S{sup 2-}) units, with structures related to either pyrrhotite (Fe{sub 1-x}S) or greigite (Fe{sub 3}S{sub 4}). A third component probably corresponds to a mononuclear low spin Fe(II) complex, involving sulfur and fulvic acid in the iron coordination sphere. These species were oxygen-sensitive and decomposed to yield magnetically dilute Fe(III) complexes and Fe(III) oxyhydroxides on aeration of the solutions.

  6. A New Process for Acrylic Acid Synthesis by Fermentative Process

    Science.gov (United States)

    Lunelli, B. H.; Duarte, E. R.; de Toledo, E. C. Vasco; Wolf Maciel, M. R.; Maciel Filho, R.

    With the synthesis of chemical products through biotechnological processes, it is possible to discover and to explore innumerable routes that can be used to obtain products of high addes value. Each route may have particular advantages in obtaining a desired product, compared with others, especially in terms of yield, productivity, easiness to separate the product, economy, and environmental impact. The purpose of this work is the development of a deterministic model for the biochemical synthesis of acrylic acid in order to explore an alternative process. The model is built-up with the tubular reactor equations together with the kinetic representation based on the structured model. The proposed process makes possible to obtain acrylic acid continuously from the sugar cane fermentation.

  7. Fatty Acid Methyl Esters of Melon Seed Oil: Characterisation for Potential Diesel Fuel Application

    Directory of Open Access Journals (Sweden)

    Paul M. EJIKEME

    2011-06-01

    Full Text Available Fatty acid methyl esters (FAME, biodiesel, are alternative diesel fuels usually obtained from renewable sources, mainly, vegetable and animal oils through transesterification among other processes. Melon seed oil was extracted from melon seeds bought from a local market, degummed and alkali refined using standard methods. FAME of the oil was produced using methanol in the molar ration of 1:6, 1% sodium hydroxide catalyst at the reaction temperature of 60 deg C for the duration of 1h. Results obtained showed that the fatty acid methyl esters had a specific gravity of 0.8786, viscosity of 6.24 centistokes, pH of 7.23, heating value of 36.34 J/g and flash point of 148 deg C. The FAME yield was 87.35% under the reaction conditions that applied. The infrared spectra of both the refined oil and the methyl esters from it, showed peaks at 1721.3cm-1 and 1167.8cm-1 (C=O and C-O stretches large and medium absorbance's for oils and methyl esters. Generally, the fuel properties of the FAME compared with values obtained under the same conditions for conventional petroleum diesel that was sourced from a retail outlet; suggesting that biodiesel from MSO could be used alone or in blends with petrodiesel to power compression ignition (diesel engines.

  8. Synthesis of Rosin Acid Starch Catalyzed by Lipase

    OpenAIRE

    Rihui Lin; He Li; Han Long; Jiating Su; Wenqin Huang

    2014-01-01

    Rosin, an abundant raw material from pine trees, was used as a starting material directly for the synthesis of rosin acid starch. The esterification reaction was catalyzed by lipase (Novozym 435) under mild conditions. Based on single factor experimentation, the optimal esterification conditions were obtained as follows: rosin acid/anhydrous glucose unit in the molar ratio 2 : 1, reaction time 4 h at 45°C, and 15% of lipase dosage. The degree of substitution (DS) reaches 0.098. Product from e...

  9. Fabrication and characterisation of high performance polypyrrole modified microarray sensor for ascorbic acid determination

    Energy Technology Data Exchange (ETDEWEB)

    Samseya, J. [Alagappa University, Karaikudi, Tamil Nadu (India); Srinivasan, R., E-mail: sivarunjan@gmail.com [Central Electro Chemical Research Insititute, Karaikudi, Tamil Nadu (India); Chang, Yu-Tsern; Tsao, Cheng-Wen [Department of Cosmetic Applications, Taoyuan Innovation Institute of Technology, Taiwan (China); Vasantha, V.S. [Madurai Kamaraj University, Madurai, Tamil Nadu (India)

    2013-09-02

    Graphical abstract: -- Highlights: •Gold microelectrode array (Au/MEA) with electrode of 12 μm diameter was fabricated by photolithography technique. •Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared. •Ppy/Au/MEA used for ascorbic acid determination in the presence of different neurotransmitters. •The micro array exhibited wide linear range, very high sensitivity and very low LOD than the earlier reports. •It was used successfully to test ascorbic acid in different types real samples. -- Abstract: In this study, gold microelectrode array (Au/MEA) with electrode of 12 μm diameter was fabricated by photolithography technique. Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared by cyclic voltammetry technique. The deposition potential range and number of cycles were optimised in order to get optimum thickness of Ppy film. Scanning Electron Microscope and Atomic Force Microscope investigations reveal that Ppy coating formed at 3 cycles is porous with thickness of 1.5 μm which exhibiting high catalytic current for ascorbic acid (AA) in square wave technique (SWV). In contrast to earlier sensors designs, these Ppy/Au/MEA sensors exhibits lower detection limit (LOD) of 10 nm towards AA at physiological conditions. It also exhibits enhanced sensitivity (2.5 mA cm{sup −2} mM{sup −1}) and long range of linear detection limit from 10 nm to 2.8 mM. In the same way, polypyrrole modified macro Au (Ppy/Au/MA) biosensor was also fabricated and its electro catalytic property towards AA was compared with that of Ppy/Au/MEA. The Ppy/Au/MA exhibits sensitivity of only 0.27 mA cm{sup −2} mM{sup −1}, LOD of 5 μM and linear range of 10 μM to 2.2 mM. Hence, our investigations indicate that the Ppy/Au/MEA could serve as highly sensitive sensor for AA than any of the earlier designs. So, the Ppy/Au/MEA electrode was utilised for determination AA in a wide variety of real samples.

  10. A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

    Science.gov (United States)

    Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L

    2015-04-01

    The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

  11. Synthesis of Rosin Acid Starch Catalyzed by Lipase

    Directory of Open Access Journals (Sweden)

    Rihui Lin

    2014-01-01

    Full Text Available Rosin, an abundant raw material from pine trees, was used as a starting material directly for the synthesis of rosin acid starch. The esterification reaction was catalyzed by lipase (Novozym 435 under mild conditions. Based on single factor experimentation, the optimal esterification conditions were obtained as follows: rosin acid/anhydrous glucose unit in the molar ratio 2 : 1, reaction time 4 h at 45°C, and 15% of lipase dosage. The degree of substitution (DS reaches 0.098. Product from esterification of cassava starch with rosin acid was confirmed by FTIR spectroscopy and iodine coloration analysis. Scanning electron microscopy and X-ray diffraction analysis showed that the morphology and crystallinity of the cassava starch were largely destroyed. Thermogravimetric analysis indicated that thermal stability of rosin acid starch decreased compared with native starch.

  12. Facile Synthesis of Oleanolic Acid Monoglycosides and Diglycosides

    Directory of Open Access Journals (Sweden)

    Mao-Sheng Cheng

    2008-07-01

    Full Text Available Oleanolic acid and its glycosides are important natural products, possessing various attractive biological activities such as antitumor, antivirus and anti-inflammatory properties. In the present work, fifteen oleanolic acid saponins bearing various saccharide moieties, including 3-monoglycoside, 28-monoglycoside and 3,28-diglycoside, were easily synthesized in high yields. Benzyl was chosen as the protective group for the COOH(28 group, instead of commonly used methyl and allyl, to avoid difficulties in the final deprotection. Alkali-promoted condensation of the carboxylic acid with bromoglycosides was found to be more efficient in the synthesis of 28-glycosides. Two approaches were investigated and proved practicable in the preparation of 3,28- diglycosides. This method is suitable for preparing oleanolic acid glycosides with structural diversity for extensive biological evaluation and structure-activity relationship study, and it also apply new idea for the corresponding synthetic methods to the glycoside derivatives of other triterpenoid.

  13. Very long chain fatty acid synthesis in sunflower kernels.

    Science.gov (United States)

    Salas, Joaquín J; Martínez-Force, Enrique; Garcés, Rafael

    2005-04-01

    Most common seed oils contain small amounts of very long chain fatty acids (VLCFAs), the main components of oils from species such as Brassica napus or Lunnaria annua. These fatty acids are synthesized from acyl-CoA precursors in the endoplasmic reticulum through the activity of a dissociated enzyme complex known as fatty acid elongase. We studied the synthesis of the arachidic, behenic, and lignoceric VLCFAs in sunflower kernels, in which they account for 1-3% of the saturated fatty acids. These VLCFAs are synthesized from 18:0-CoA by membrane-bound fatty acid elongases, and their biosynthesis is mainly dependent on NADPH equivalents. Two condensing enzymes appear to be responsible for the synthesis of VLCFAs in sunflower kernels, beta-ketoacyl-CoA synthase-I (KCS-I) and beta-ketoacyl-CoA synthase-II (KCS-II). Both of these enzymes were resolved by ion exchange chromatography and display different substrate specificities. While KCS-I displays a preference for 20:0-CoA, 18:0-CoA was more efficiently elongated by KCS-II. Both enzymes have different sensitivities to pH and Triton X-100, and their kinetic properties indicate that both are strongly inhibited by the presence of their substrates. In light of these results, the VLCFA composition of sunflower oil is considered in relation to that in other commercially exploited oils.

  14. Functionalisation of mesoporous silica gel with 2-[(phosphonomethyl)-amino]acetic acid functional groups. Characterisation and application

    International Nuclear Information System (INIS)

    A new complexing adsorbent was prepared by chemical modification of mesoporous silica Kieselgel 60 (dp = 37–63 μm, average pore size 6 nm, specific surface area 425 m2 g−1) with 3-glycidoxypropyltrimethoxysilane and 2-[(phosphonomethyl)amino]acetic acid (PMA), commonly known as glyphosate. The prepared adsorbent was fully characterised using elemental analysis, thermal gravimetric analysis (TGA), acid–base potentiometric titration, Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption isotherms at 77 K (BET), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The concentration of bonded PMA groups calculated from the nitrogen content was 0.38 mmol per gram. The adsorption of transition metal ions on PMA functionalised silica (HEPMAS) was studied from aqueous solutions having different pH and the following selectivity was established, Zn(II) 4, 4.9 × 105 and 2.6 × 104 for Zn(II), Pb(II) and Cd(II), respectively.

  15. Functionalisation of mesoporous silica gel with 2-[(phosphonomethyl)-amino]acetic acid functional groups. Characterisation and application

    Energy Technology Data Exchange (ETDEWEB)

    Caldarola, Dario [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Australian Centre for Research on Separation Sciences (ACROSS), University of Tasmania, Hobart, Tasmania 7001 (Australia); Mitev, Dimitar P. [Australian Centre for Research on Separation Sciences (ACROSS), University of Tasmania, Hobart, Tasmania 7001 (Australia); Marlin, Lucile [Ecole Nationale Superieure des Ingenieurs en Arts Chimiques et Technologiquesm, Toulouse (France); Irish Separation Science Cluster, Dublin City University, Dublin (Ireland); Nesterenko, Ekaterina P. [Irish Separation Science Cluster, Dublin City University, Dublin (Ireland); Paull, Brett [Australian Centre for Research on Separation Sciences (ACROSS), University of Tasmania, Hobart, Tasmania 7001 (Australia); Onida, Barbara [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); CR-INSTM for Materials with Controlled Porosity (Italy); Bruzzoniti, Maria Concetta; Carlo, Rosa Maria De; Sarzanini, Corrado [Analytical Chemistry Department, University of Torino, Via P. Giuria 5, 10125 Torino (Italy); Nesterenko, Pavel N., E-mail: Pavel.Nesterenko@utas.edu.au [Australian Centre for Research on Separation Sciences (ACROSS), University of Tasmania, Hobart, Tasmania 7001 (Australia)

    2014-01-01

    A new complexing adsorbent was prepared by chemical modification of mesoporous silica Kieselgel 60 (d{sub p} = 37–63 μm, average pore size 6 nm, specific surface area 425 m{sup 2} g{sup −1}) with 3-glycidoxypropyltrimethoxysilane and 2-[(phosphonomethyl)amino]acetic acid (PMA), commonly known as glyphosate. The prepared adsorbent was fully characterised using elemental analysis, thermal gravimetric analysis (TGA), acid–base potentiometric titration, Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption isotherms at 77 K (BET), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The concentration of bonded PMA groups calculated from the nitrogen content was 0.38 mmol per gram. The adsorption of transition metal ions on PMA functionalised silica (HEPMAS) was studied from aqueous solutions having different pH and the following selectivity was established, Zn(II) < Co(II) < Cd(II) < Mn(II) < Ni(II) < Cu(II). The calculated values of distribution coefficients D for the adsorption of ecotoxic metal ions on HEPMAS are 5.0 × 10{sup 4}, 4.9 × 10{sup 5} and 2.6 × 10{sup 4} for Zn(II), Pb(II) and Cd(II), respectively.

  16. Tailored fatty acid synthesis via dynamic control of fatty acid elongation

    OpenAIRE

    Torella, Joseph P.; Ford, Tyler J.; Kim, Scott N.; Chen, Amanda M.; Way, Jeffrey C; Silver, Pamela A

    2013-01-01

    Medium-chain fatty acids (MCFAs, 4–12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even- and odd-chain–length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, there...

  17. PlsX deletion impacts fatty acid synthesis and acid adaptation in Streptococcus mutans.

    Science.gov (United States)

    Cross, Benjamin; Garcia, Ariana; Faustoferri, Roberta; Quivey, Robert G

    2016-04-01

    Streptococcus mutans, one of the primary causative agents of dental caries in humans, ferments dietary sugars in the mouth to produce organic acids. These acids lower local pH values, resulting in demineralization of the tooth enamel, leading to caries. To survive acidic environments, Strep. mutans employs several adaptive mechanisms, including a shift from saturated to unsaturated fatty acids in membrane phospholipids. PlsX is an acyl-ACP : phosphate transacylase that links the fatty acid synthase II (FASII) pathway to the phospholipid synthesis pathway, and is therefore central to the movement of unsaturated fatty acids into the membrane. Recently, we discovered that plsX is not essential in Strep. mutans. A plsX deletion mutant was not a fatty acid or phospholipid auxotroph. Gas chromatography of fatty acid methyl esters indicated that membrane fatty acid chain length in the plsX deletion strain differed from those detected in the parent strain, UA159. The deletion strain displayed a fatty acid shift similar to WT, but had a higher percentage of unsaturated fatty acids at low pH. The deletion strain survived significantly longer than the parent strain when cultures were subjected to an acid challenge of pH 2.5.The ΔplsX strain also exhibited elevated F-ATPase activity at pH 5.2, compared with the parent. These results indicate that the loss of plsX affects both the fatty acid synthesis pathway and the acid-adaptive response of Strep. mutans. PMID:26850107

  18. Genetic and Technological Characterisation of Vineyard- and Winery-Associated Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Aspasia A. Nisiotou

    2015-01-01

    Full Text Available Vineyard- and winery-associated lactic acid bacteria (LAB from two major PDO regions in Greece, Peza and Nemea, were surveyed. LAB were isolated from grapes, fermenting musts, and winery tanks performing spontaneous malolactic fermentations (MLF. Higher population density and species richness were detected in Nemea than in Peza vineyards and on grapes than in fermenting musts. Pediococcus pentosaceus and Lactobacillus graminis were the most abundant LAB on grapes, while Lactobacillus plantarum dominated in fermenting musts from both regions. No particular structure of Lactobacillus plantarum populations according to the region of origin was observed, and strain distribution seems random. LAB species diversity in winery tanks differed significantly from that in vineyard samples, consisting principally of Oenococcus oeni. Different strains were analysed as per their enological characteristics and the ability to produce biogenic amines (BAs. Winery-associated species showed higher resistance to low pH, ethanol, SO2, and CuSO4 than vineyard-associated isolates. The frequency of BA-producing strains was relatively low but not negligible, considering that certain winery-associated Lactobacillus hilgardii strains were able to produce BAs. Present results show the necessity of controlling the MLF by selected starters in order to avoid BA accumulation in wine.

  19. Structural and rheological characterisation of heteropolysaccharides produced by lactic acid bacteria in wheat and sorghum sourdough.

    Science.gov (United States)

    Galle, Sandra; Schwab, Clarissa; Arendt, Elke K; Gänzle, Michael G

    2011-05-01

    Hydrocolloids improve the volume, texture, and shelf life of bread. Exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) during sourdough fermentation can replace hydrocolloids. It was the aim of this study to determine whether heteropolysaccharides (HePS) synthesized intracellularly from sugar nucleotides by glycosyltransferases are produced in wheat and gluten-free sorghum sourdough at effective levels. The HePS-producing strains Lactobacillus casei FUA3185, L. casei FUA3186, and Lactobacillus buchneri FUA3154 were used; Weissella cibaria 10M producing no EPS in the absence of sucrose served as control strain. Cell suspensions of L. buchneri in MRS showed the highest viscosity at low shear rate. Glycosyltransferase genes responsible of HePS formation in LAB were expressed in sorghum and wheat sourdough. However, only HePS produced by L. buchneri influenced the rheological properties of sorghum sourdoughs but not of wheat sourdoughs. Sorghum sourdough fermented with L. buchneri exhibited a low |G*| compared to the control, indicating a decrease in resistance to deformation. An increase in tan δ indicated decreased elasticity. The use of LAB producing HePS expands the diversity of EPS and increases the variety of cultures for use in baking.

  20. Structural and rheological characterisation of heteropolysaccharides produced by lactic acid bacteria in wheat and sorghum sourdough.

    Science.gov (United States)

    Galle, Sandra; Schwab, Clarissa; Arendt, Elke K; Gänzle, Michael G

    2011-05-01

    Hydrocolloids improve the volume, texture, and shelf life of bread. Exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) during sourdough fermentation can replace hydrocolloids. It was the aim of this study to determine whether heteropolysaccharides (HePS) synthesized intracellularly from sugar nucleotides by glycosyltransferases are produced in wheat and gluten-free sorghum sourdough at effective levels. The HePS-producing strains Lactobacillus casei FUA3185, L. casei FUA3186, and Lactobacillus buchneri FUA3154 were used; Weissella cibaria 10M producing no EPS in the absence of sucrose served as control strain. Cell suspensions of L. buchneri in MRS showed the highest viscosity at low shear rate. Glycosyltransferase genes responsible of HePS formation in LAB were expressed in sorghum and wheat sourdough. However, only HePS produced by L. buchneri influenced the rheological properties of sorghum sourdoughs but not of wheat sourdoughs. Sorghum sourdough fermented with L. buchneri exhibited a low |G*| compared to the control, indicating a decrease in resistance to deformation. An increase in tan δ indicated decreased elasticity. The use of LAB producing HePS expands the diversity of EPS and increases the variety of cultures for use in baking. PMID:21356463

  1. Synthesis of a tetrasaccharide fragment of hyaluronic acid having a glucuronic acid at the reducing end

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Slaghek, T.M.; Hyppönen, T.K.; Ogawa, T.; Kamerling, J.P.

    1993-01-01

    A stereocontrolled synthesis of a tetrasaccharide fragment of hyaluronic acid, beta-p-methoxyphenyl glycoside of beta-D-GlcNAc-(1¨4)-beta-D-GlcNAc-(1¨3)-beta-D-GlcNAc-(1¨4)-D-GlcA, is presented.

  2. Catalytic asymmetric synthesis of phthioceranic acid, a heptamethyl-branched acid from Mycobacterium tuberculosis

    NARCIS (Netherlands)

    ter Horst, B.; Feringa, B.L.; J. Minnaard, A.

    2007-01-01

    The first total synthesis of phthioceranic acid (1) has been achieved by an iterative catalytic asymmetric 1,4-addition protocol. This method provides a robust and high-yielding route for the preparation of 1,3-oligomethyl (deoxypropionate) arrays. After the desired number of methyl groups has been

  3. Folate/NIR 797-conjugated albumin magnetic nanospheres: synthesis, characterisation, and in vitro and in vivo targeting evaluation.

    Directory of Open Access Journals (Sweden)

    Qiusha Tang

    Full Text Available A practical and effective strategy for synthesis of Folate-NIR 797-conjugated Magnetic Albumin Nanospheres (FA-NIR 797-MAN was developed. For this strategy, Magnetic Albumin Nanospheres (MAN, composed of superparamagnetic iron oxide nanoparticles (SPIONs and bovine serum albumin (BSA, were covalently conjugated with folic acid (FA ligands to enhance the targeting capability of the particles to folate receptor (FR over-expressing tumours. Subsequently, a near-infrared (NIR fluorescent dye NIR 797 was conjugated with FA-conjugated MAN for in vivo fluorescence imaging. The FA-NIR 797-MAN exhibited low toxicity to a human nasopharyngeal epidermal carcinoma cell line (KB cells. Additionally, in vitro and in vivo evaluation of the dynamic behaviour and targeting ability of FA-NIR 797-MAN to KB tumours validated the highly selective affinity of FA-NIR 797-MAN for FR-positive tumours. In summary, the FA-NIR 797-MAN prepared here exhibited great potential for tumour imaging, since the near-infrared fluorescence contrast agents target cells via FR-mediated endocytosis. The high fluorescence intensity together with the targeting effect makes FA-NIR 797-MAN a promising candidate for imaging, monitoring, and early diagnosis of cancer at the molecular and cellular levels.

  4. Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A; Synthese de derives de l'acide tetronique et de l'acide pulvinique. Synthese totale de la norbadione A

    Energy Technology Data Exchange (ETDEWEB)

    Mallinger, A

    2008-11-15

    When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A.

  5. Synthesis and Characterization of Fatty Acid Conjugates of Niacin and Salicylic Acid.

    Science.gov (United States)

    Vu, Chi B; Bemis, Jean E; Benson, Ericka; Bista, Pradeep; Carney, David; Fahrner, Richard; Lee, Diana; Liu, Feng; Lonkar, Pallavi; Milne, Jill C; Nichols, Andrew J; Picarella, Dominic; Shoelson, Adam; Smith, Jesse; Ting, Amal; Wensley, Allison; Yeager, Maisy; Zimmer, Michael; Jirousek, Michael R

    2016-02-11

    This report describes the synthesis and preliminary biological characterization of novel fatty acid niacin conjugates and fatty acid salicylate conjugates. These molecular entities were created by covalently linking two bioactive molecules, either niacin or salicylic acid, to an omega-3 fatty acid. This methodology allows the simultaneous intracellular delivery of two bioactives in order to elicit a pharmacological response that could not be replicated by administering the bioactives individually or in combination. The fatty acid niacin conjugate 5 has been shown to be an inhibitor of the sterol regulatory element binding protein (SREBP), a key regulator of cholesterol metabolism proteins such as PCSK9, HMG-CoA reductase, ATP citrate lyase, and NPC1L1. On the other hand, the fatty acid salicylate conjugate 11 has been shown to have a unique anti-inflammatory profile based on its ability to modulate the NF-κB pathway through the intracellular release of the two bioactives.

  6. Synthesis and characterization of magnetite nanoparticles coated with lauric acid

    International Nuclear Information System (INIS)

    Understanding the process of synthesis of magnetic nanoparticles is important for its implementation in in vitro and in vivo studies. In this work we report the synthesis of magnetic nanoparticles made from ferrous oxide through coprecipitation chemical process. The nanostructured material was coated with lauric acid and dispersed in aqueous medium containing surfactant that yielded a stable colloidal suspension. The characterization of magnetic nanoparticles with distinct physico-chemical configurations is fundamental for biomedical applications. Therefore magnetic nanoparticles were characterized in terms of their morphology by means of TEM and DLS, which showed a polydispersed set of spherical nanoparticles (average diameter of ca. 9 nm) as a result of the protocol. The structural properties were characterized by using X-ray diffraction (XRD). XRD pattern showed the presence of peaks corresponding to the spinel phase of magnetite (Fe3O4). The relaxivities r2 and r2* values were determined from the transverse relaxation times T2 and T2* at 3 T. Magnetic characterization was performed using SQUID and FMR, which evidenced the superparamagnetic properties of the nanoparticles. Thermal characterization using DSC showed exothermic events associated with the oxidation of magnetite to maghemite. - Highlights: • Synthesis of magnetic nanoparticles coated with lauric acid • Characterization of magnetic nanoparticles • Morphological, structural, magnetic, calorimetric and relaxometric characterization

  7. Synthesis and characterization of magnetite nanoparticles coated with lauric acid

    Energy Technology Data Exchange (ETDEWEB)

    Mamani, J.B., E-mail: javierbm@einstein.br [Instituto do Cérebro-InCe, Hospital Israelita Albert Einstein-HIAE, 05651-901 São Paulo (Brazil); Costa-Filho, A.J. [Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto (Brazil); Cornejo, D.R. [Instituto de Física Universidade de São Paulo, USP, São Paulo (Brazil); Vieira, E.D. [Instituto de Física, Universidade Federal de Goiás, Goiânia (Brazil); Gamarra, L.F. [Instituto do Cérebro-InCe, Hospital Israelita Albert Einstein-HIAE, 05651-901 São Paulo (Brazil)

    2013-07-15

    Understanding the process of synthesis of magnetic nanoparticles is important for its implementation in in vitro and in vivo studies. In this work we report the synthesis of magnetic nanoparticles made from ferrous oxide through coprecipitation chemical process. The nanostructured material was coated with lauric acid and dispersed in aqueous medium containing surfactant that yielded a stable colloidal suspension. The characterization of magnetic nanoparticles with distinct physico-chemical configurations is fundamental for biomedical applications. Therefore magnetic nanoparticles were characterized in terms of their morphology by means of TEM and DLS, which showed a polydispersed set of spherical nanoparticles (average diameter of ca. 9 nm) as a result of the protocol. The structural properties were characterized by using X-ray diffraction (XRD). XRD pattern showed the presence of peaks corresponding to the spinel phase of magnetite (Fe{sub 3}O{sub 4}). The relaxivities r{sub 2} and r{sub 2}* values were determined from the transverse relaxation times T{sub 2} and T{sub 2}* at 3 T. Magnetic characterization was performed using SQUID and FMR, which evidenced the superparamagnetic properties of the nanoparticles. Thermal characterization using DSC showed exothermic events associated with the oxidation of magnetite to maghemite. - Highlights: • Synthesis of magnetic nanoparticles coated with lauric acid • Characterization of magnetic nanoparticles • Morphological, structural, magnetic, calorimetric and relaxometric characterization.

  8. Synthesis of zincosilicate mordenite using citric acid as complexing agent

    Institute of Scientific and Technical Information of China (English)

    MeiDong; JianjuoWang; YuhanSun

    2001-01-01

    The zincosilicate analog of zeolite mordenite was hydrothermally synthesized in the presence of citric acid and characterized with several spectroscopic techniques.The zeolite thus prepared had a higher crystallinity and Zn concentration in the framework compared with the one obtained in the absence of citric acid.XRD and FTIR provided evidence for the incorporation of Zn in the framework.Results of XAFS indicated a tetrahedral structure of Zn in the lattice framework with a Zn-O distancd of 0.1938nm.It is speculated that the citric acid might decrease the concentration of Zn2 in the synthesis mixture,there by preventing the unfavorable-formation of oxide or hydroxide species.2001 Elsevier Science B.V.All rights reserved.

  9. Cyclic Comonomers for the Synthesis of Carboxylic Acid and Amine Functionalized Poly(l-Lactic Acid

    Directory of Open Access Journals (Sweden)

    Markus Heiny

    2015-03-01

    Full Text Available Degradable aliphatic polyesters such as poly(lactic acid are widely used in biomedical applications, however, they lack functional moieties along the polymer backbone that are amenable for functionalization reactions or could be the basis for interactions with biological systems. Here we present a straightforward route for the synthesis of functional α-ω epoxyesters as comonomers for lactide polymerization. Salient features of these highly functionalized epoxides are versatility in functionality and a short synthetic route of less than four steps. The α-ω epoxyesters presented serve as a means to introduce carboxylic acid and amine functional groups into poly(lactic acid polymers via ring-opening copolymerization.

  10. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    Directory of Open Access Journals (Sweden)

    M. Onciu

    2005-02-01

    Full Text Available Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP and pyridine (Py as bases and N-methyl-2-pyrolidinone (NMP as solvent, at reflux (180-190°C for 8-12 hours.

  11. Activation of PPARα by Fatty Acid Accumulation Enhances Fatty Acid Degradation and Sulfatide Synthesis.

    Science.gov (United States)

    Yang, Yang; Feng, Yuyao; Zhang, Xiaowei; Nakajima, Takero; Tanaka, Naoki; Sugiyama, Eiko; Kamijo, Yuji; Aoyama, Toshifumi

    2016-01-01

    Very-long-chain acyl-CoA dehydrogenase (VLCAD) catalyzes the first reaction in the mitochondrial fatty acid β-oxidation pathway. VLCAD deficiency is associated with the accumulation of fat in multiple organs and tissues, which results in specific clinical features including cardiomyopathy, cardiomegaly, muscle weakness, and hepatic dysfunction in infants. We speculated that the abnormal fatty acid metabolism in VLCAD-deficient individuals might cause cell necrosis by fatty acid toxicity. The accumulation of fatty acids may activate peroxisome proliferator-activated receptor (PPAR), a master regulator of fatty acid metabolism and a potent nuclear receptor for free fatty acids. We examined six skin fibroblast lines, derived from VLCAD-deficient patients and identified fatty acid accumulation and PPARα activation in these cell lines. We then found that the expression levels of three enzymes involved in fatty acid degradation, including long-chain acyl-CoA synthetase (LACS), were increased in a PPARα-dependent manner. This increased expression of LACS might enhance the fatty acyl-CoA supply to fatty acid degradation and sulfatide synthesis pathways. In fact, the first and last reactions in the sulfatide synthesis pathway are regulated by PPARα. Therefore, we also measured the expression levels of enzymes involved in sulfatide metabolism and the regulation of cellular sulfatide content. The levels of these enzymes and cellular sulfatide content both increased in a PPARα-dependent manner. These results indicate that PPARα activation plays defensive and compensative roles by reducing cellular toxicity associated with fatty acids and sulfuric acid. PMID:27644403

  12. Chromatographic characterisation, under highly aqueous conditions, of a molecularly imprinted polymer binding the herbicide 2,4-dichlorophenoxyacetic acid.

    Science.gov (United States)

    Legido-Quigley, C; Oxelbark, J; De Lorenzi, E; Zurutuza-Elorza, A; Cormack, P A G

    2007-05-15

    The affinity of a 2,4-dichlorophenoxyacetic acid (2,4-D) molecularly imprinted polymer (MIP), which was synthesised directly in an aqueous organic solvent, for its template (2,4-D) was studied and compared with the affinity exhibited by two other reference (control) polymers, NIPA and NIPB, for the same analyte. Zonal chromatography was performed to establish the optimal selectivity, expressed as imprinting factor (IF), under chromatographic conditions more aqueous than those described so far in the literature. Frontal analysis (FA) was performed on columns packed with these polymers, using an optimized mobile phase composed of methanol/phosphate buffer (50/50, v/v), to extract adsorption isotherm data and retrieve binding parameters from the best isotherm model. Surprisingly, the template had comparable and strong affinity for both MIP (K = 3.8x10(4) M(-1)) and NIPA (K = 1.9x10(4) M(-1)), although there was a marked difference in the saturation capacities of selective and non-selective sites, as one would expect for an imprinted polymer. NIPB acts as a true control polymer in the sense that it has relatively low affinity for the template (K = 8.0x10(2) M(-1)). This work provides the first frontal chromatographic characterization of such a polymer in a water-rich environment over a wide concentration range. The significance of this work stems from the fact that the chromatographic approach used is generic and can be applied readily to other analytes, but also because there is an increasing demand for well-characterised imprinted materials that function effectively in aqueous media and are thus well-suited for analytical science applications involving, for example, biofluids and environmental water samples.

  13. Optimization of Butylphosphate synthesis from O-Phosphoric Acid

    International Nuclear Information System (INIS)

    This work was carried out in order to confirm results of previous work and to enhance the yield of TBP synthesis. This, many reactions have been realised under differents experimental condition (temperature, acid/ alcool molar ratio, pressure and the quantity of promoter agent 'POCL3'). the TBP yield variations as function the experimental parameters, has been expressed, using the 2n factorial plan mathematical model. The experimental results were compared to those given by the theoritical model, and the optimal conditions were then drawn out

  14. Synthesis of a Nitro Analogue of Plakoric Acid

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Qi; JIN,Hong-Xia; LIU,He-Hua; WU,Yi-Kang

    2006-01-01

    Synthesis of a nitro analogue of plakoric acid is presented. The peroxy bond was incorporated into the substrate structure through a boron trifluoride etherate catalyzed methoxy-hydroperoxy group partial exchange reaction in djethyl ether with urea-hydrogen peroxide complex (UHP, a commercially available solid reagent) as the source of the hydrogen peroxide. Under the given conditions, only one of the two methoxyl groups underwent the MeO-OOH exchange and the resulting hydroperoxy hemiketal proceeded directly to the end product through an intramolecular Michael addition of the hydroperoxyl group to the nitro group activated carbon-carbon double bond.

  15. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  16. Lactic acid demineralization of shrimp shell and chitosan synthesis

    Directory of Open Access Journals (Sweden)

    Alewo Opuada AMEH

    2015-05-01

    Full Text Available The use of lactic acid was compared to hydrochloric acid for shrimp shell demineralization in chitosan synthesis. Five different acid concentrations were considered for the study: 1.5M, 3.0M, 4.5M, 6.0M and 7.5M. After demineralization, the shrimp shell were deproteinized and subsequently deacetylated to produce chitosan using sodium hydroxide solution. The synthesized chitosan samples were characterized using solubility, FTIR, SEM, XRD and viscosity. The SEM, FTIR and XRD analysis indicated that chitosan was synthesized with a high degree of deacetylation (83.18±2.11 when lactic acid was used and 84.2±5.00 when HCl was used. The degree of deacetylation and the molecular weight of the chitosan samples were also estimated. ANOVA analysis (at 95% confidence interval indicated that acid type and concentration did not significantly affect the solubility, degree of deacetylation, viscosity and molecular weight of the chitosan within the range considered.

  17. Synthesis, characterisation and adsorption properties of a porous copper(II) 3D coordination polymer exhibiting strong binding enthalpy and adsorption capacity for carbon dioxide.

    Science.gov (United States)

    Eckold, Pierre; Gee, William J; Hill, Matthew R; Batten, Stuart R

    2012-11-21

    The synthesis and characterisation of microporous coordination polymers containing copper(II) or cobalt(II) and 2-(pyridin-4-yl)malonaldehyde (Hpma) is described and the gas adsorption properties evaluated. Single-crystal X-ray structure determinations identified the structures as [M(pma)(2)]·2X (M = Cu, 1; Co, 2; X = MeOH, MeCN), which contain 3D networks with rutile topology and continuous 1D rectangular channels with diameters ranging from 3 to 4 Å. The materials exhibit low BET surface areas of 143 m(2) g(-1), but possess large capacities for carbon dioxide capture of 14.1 wt%. The small pore channels are shown to account for this, delivering a particularly strong binding enthalpy to adsorbed CO(2) of 38 kJ mol(-1), and a very large adsorption capacity relative to the low surface area.

  18. Synthesis and characterization of acidic mesoporous borosilicate thin films.

    Science.gov (United States)

    Xiu, Tongping; Liu, Qian; Wang, Jiacheng

    2009-02-01

    Work on the synthesis and characterization of acidic wormhole-like ordered mesoporous borosilicate thin films (MBSTFs) on silicon wafers is described in this paper. The MBSTFs coated by the dip-coating method were prepared through an evaporation-induced self-assembly (EISA) process using nonionic block copolymers as structure-directing agents. Fourier transform infrared (FT-IR) spectroscopy confirmed the formation of borosiloxane bonds (Si-O-B). High-resolution transmission electron microscopy (HRTEM) and N2 sorption evidenced a wormhole-like mesoporous structure in the MBSTFs obtained. Scanning electron microscopy (SEM) images of the cross sections and surfaces of the samples showed that MBSTFs on silicon wafers were continuous, homogeneous and did not crack. The acidic properties of the MBSTFs were characterized by FT-IR spectra of chemisorbed pyridine. The MBSTFs thus prepared may find their future applications in many fields including chemical sensors, catalysis, optical coating, molecule separation, etc. PMID:19441565

  19. Indoleacetic Acid synthesis in soybean cotyledon callus tissue.

    Science.gov (United States)

    Black, R C; Hamilton, R H

    1976-03-01

    Growth of an auxin-requiring soybean cotyledon callus tissue (Glycine max L., Merr. var. Acme) was promoted by tryptophan, tryptamine, indole, indoleacetamide and, to a very slight degree, anthranilic acid. When tryptophan-3-(14)C was supplied in the growth medium, labeled indoleacetic acid (IAA) was found in both the tissue and the medium. Medium, from which the cells had been removed, was also found to convert labeled tryptophan to IAA. Soybean callus contained 0.044 mumole/g free tryptophan, but this is apparently not available for conversion to IAA. These results suggest that while exogenously supplied trytophan could elevate a specific internal pool where IAA synthesis occurs some of the growth on a tryptophan medium can be accounted for by external conversion.

  20. Effect of mitochondrial ascorbic acid synthesis on photosynthesis.

    Science.gov (United States)

    Senn, M E; Gergoff Grozeff, G E; Alegre, M L; Barrile, F; De Tullio, M C; Bartoli, C G

    2016-07-01

    Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of l-galactono-1,4-lactone (l-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of l-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, l-GalL treatment increased CO2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after l-GalL treatment. Increased CO2 assimilation correlated with increased leaf stomatal conductance observed in l-GalL-treated vtc2 plants. PMID:27010742

  1. Alternative kynurenic acid synthesis routes studied in the rat cerebellum

    Directory of Open Access Journals (Sweden)

    Tonali eBlanco Ayala

    2015-05-01

    Full Text Available Kynurenic acid (KYNA, an astrocyte-derived, endogenous antagonist of α7 nicotinic acetylcholine and excitatory amino acid receptors, regulates glutamatergic, GABAergic, cholinergic and dopaminergic neurotransmission in several regions of the rodent brain. Synthesis of KYNA in the brain and elsewhere is generally attributed to the enzymatic conversion of L-kynurenine (L-KYN by kynurenine aminotransferases (KATs. However, alternative routes, including KYNA formation from D-kynurenine (D-KYN by D-amino acid oxidase (DAAO and the direct transformation of kynurenine to KYNA by reactive oxygen species (ROS, have been demonstrated in the rat brain. Using the rat cerebellum, a region of low KAT activity and high DAAO activity, the present experiments were designed to examine KYNA production from L-KYN or D-KYN by KAT and DAAO, respectively, and to investigate the effect of ROS on KYNA synthesis. In chemical combinatorial systems, both L-KYN and D-KYN interacted directly with peroxynitrite (ONOO- and hydroxyl radicals (OH•, resulting in the formation of KYNA. In tissue homogenates, the non-specific KAT inhibitor aminooxyacetic acid (AOAA; 1 mM reduced KYNA production from L-KYN and D-KYN by 85.1 ± 1.7% and 27.1 ± 4.5%, respectively. Addition of DAAO inhibitors (benzoic acid, kojic acid or 3-methylpyrazole-5-carboxylic acid; 5 µM each attenuated KYNA formation from L-KYN and D-KYN by ~35% and ~66%, respectively. ONOO- (25 µM potentiated KYNA production from both L-KYN and D-KYN, and these effects were reduced by DAAO inhibition. AOAA attenuated KYNA production from L-KYN + ONOO- but not from D-KYN + ONOO-. In vivo, extracellular KYNA levels increased rapidly after perfusion of ONOO- and, more prominently, after subsequent perfusion with L-KYN or D-KYN (100 µM. Taken together, these results suggest that different mechanisms are involved in KYNA production in the rat cerebellum, and that, specifically, DAAO and ROS can function as alternative routes

  2. AMINO ACIDS AUGMENT MUSCLE PROTEIN SYNTHESIS IN NEONATAL PIGS DURING ENDOTOXEMIA BY MODULATING TRANSLATION INITIATION

    Science.gov (United States)

    In adults, sepsis reduces protein synthesis in skeletal muscle by restraining translation. The effect of sepsis on amino acid-stimulated muscle protein synthesis has not been determined in neonates, a population who is highly anabolic and whose muscle protein synthesis rates are uniquely sensitive ...

  3. Lewis Acidic Ionic Liquids As New Addition Catalyst For Oleic Acid To Monoestolide Synthesis

    Directory of Open Access Journals (Sweden)

    Nadia Farhana Adnan

    2011-09-01

    Full Text Available Estolide compound has a large potential in many industrial applications such as biodegradable lubricants and in cosmetic formulation. In this study, monoestolide can be prepared by addition reaction of oleic acid under vacuum-reflux and solvent free condition for 10 hours at 85 °C in the presence of solid zinc chloride anhydrous (ZnCl2, choline chloride (ChCl and ionic liquids (IL ChCl-ZnCl2, ChCl-FeCl3, ChCl-SnCl2, ChCl-CuCl2 as homogenous acid catalysts. These reactions were compared with common homogenous catalyst namely sulfuric acid (H2SO4. The FTIR analysis show that addition reaction using the above catalysts showed the presence of three new peaks at 1732 cm-1 for C=O ester, 967.0 cm-1 for trans-CH=CH and 1176 cm-1 for C-O-C which confirmed the existence of monoestolide. The LC-MS results showed peak for the present of new monoestolides at retention time (tR 12.3 min corresponding to m/z 563.48. Among the IL, ChCl-ZnCl2 surprisingly exhibited higher activity which is 98 % acid oleic conversion and 80 % selective for the synthesis of monoestolides. As a result, this IL gave two potential functions as a solvent as well as a green catalyst for monoestolide synthesis from oleic acid.

  4. Quantification of ethylenediamine-N,N'-bis(hydroxysulfophenylacetic) acid regioisomers and structural characterisation of its related polycondensation products by porous graphitic carbon high-performance liquid chromatography coupled to electrospray tandem mass spectrometry.

    Science.gov (United States)

    Biasone, Alessandro; Cianci, Giusto; Di Tommaso, Donata; Piaggesi, Alberto; D'Alessandro, Nicola

    2013-10-18

    Among the commercial ethylenediamine-N,N'-bis(2-hydroxy)phenylacetic acid/iron(III) derivatives, ethylenediamine-N,N'-bis(2-hydroxy-5-sulphophenylacetic) acid/iron(III) (EDDHSA/Fe) represents one of the promising chelates for the treatment of chlorotic plants. Industrial synthesis of EDDHSA/Fe leads to relevant amounts of o,o-EDDHSA condensation products (o,o-EDDHSAcps) and other secondary products that might have important relevance from the agronomic point of view. However, their chemical structures have remained unknown to date. Analysis of iron complexes by ion-pair reversed-phase chromatography, coupled with electrospray tandem mass spectrometry revealed the presence of the meso-o,o-EDDHSA/Fe, rac-o,o-EDDHSA/Fe, o,p-EDDHSA/Fe regioisomers, the hydroxyl derivative of o,o-EDDHSA/Fe, and the three main EDDHSA condensation products chelating the iron(III) (EDDHSAcps/nFe). However, the chromatographic peaks of EDDHSAcps/Fe are not well resolved due to the large numbers of stereoisomers and the poor efficiency of the ion-pair reversed-phase separation method. An alternative chromatographic method is based on porous graphitic carbon (PGC) separation after pre-column decomplexation of the chelates with trifluoracetic acid, which was developed to allow detection of EDDHSA stereo/regioisomers, EDDHSAcps, and low-molecular-weight by-products. This extensive PGC-HPLC-ESI-MS/MS investigation provides quantitative determination of meso-o,o-EDDHSA, rac-o,o-EDDHSA and o,p-EDDHSA, in addition to characterisation of EDDHSAcps and the low-molecular-weight by-products. PGC separation coupled to a triple quadrupole ESI-MS detector allowed characterisation of free ligands using collision-induced dissociation experiments in positive and negative ionisation mode, providing comparative evaluation of EDDHSAcps in three commercial samples. For detection, the PGC-HPLC-ESI-MS/MS is the best method according to the limit of quantification and limit of detection (picomolar and sub

  5. Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway.

    Science.gov (United States)

    Jawed, Kamran; Mattam, Anu Jose; Fatma, Zia; Wajid, Saima; Abdin, Malik Z; Yazdani, Syed Shams

    2016-01-01

    Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product. PMID:27466817

  6. Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway

    Science.gov (United States)

    Jawed, Kamran; Mattam, Anu Jose; Fatma, Zia; Wajid, Saima; Abdin, Malik Z.; Yazdani, Syed Shams

    2016-01-01

    Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product. PMID:27466817

  7. Rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid

    DEFF Research Database (Denmark)

    Bunch, Lennart; Liljefors, Tommy; Greenwood, Jeremy R;

    2003-01-01

    The design and synthesis of conformationally restricted analogues of alpha-amino acids is an often used strategy in medicinal chemistry research. Here we present the rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid (1), a novel...

  8. Baker's Yeast Deficient in Storage Lipid Synthesis Uses cis-Vaccenic Acid to Reduce Unsaturated Fatty Acid Toxicity.

    Science.gov (United States)

    Sec, Peter; Garaiova, Martina; Gajdos, Peter; Certik, Milan; Griac, Peter; Hapala, Ivan; Holic, Roman

    2015-07-01

    The role of cis-vaccenic acid (18:1n-7) in the reduction of unsaturated fatty acids toxicity was investigated in baker's yeast Saccharomyces cerevisiae. The quadruple mutant (QM, dga1Δ lro1Δ are1Δ are2Δ) deficient in enzymes responsible for triacylglycerol and steryl ester synthesis has been previously shown to be highly sensitive to exogenous unsaturated fatty acids. We have found that cis-vaccenic acid accumulated during cultivation in the QM cells but not in the corresponding wild type strain. This accumulation was accompanied by a reduction in palmitoleic acid (16:1n-7) content in the QM cells that is consistent with the proposed formation of cis-vaccenic acid by elongation of palmitoleic acid. Fatty acid analysis of individual lipid classes from the QM strain revealed that cis-vaccenic acid was highly enriched in the free fatty acid pool. Furthermore, production of cis-vaccenic acid was arrested if the mechanism of fatty acids release to the medium was activated. We also showed that exogenous cis-vaccenic acid did not affect viability of the QM strain at concentrations toxic for palmitoleic or oleic acids. Moreover, addition of cis-vaccenic acid to the growth medium provided partial protection against the lipotoxic effects of exogenous oleic acid. Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.

  9. Synthesis and characterisation of simultaneous interpenetrating polymer networks (SIN formed by polystyrene and polyurethane obtained from castor oil and cassava starch polyol-suspensions

    Directory of Open Access Journals (Sweden)

    Juan Manuel Cabrera Anaya

    2011-01-01

    Full Text Available Castor oil was modified by transesterification with pentaerythritol and cassava starch was subsequently incorporated into this oil (oil modified by incorporating starch is called a polyol-suspension. Polyurethane/polystyrene SINs (simulta- neously produced IPNs were synthesised from them and styrene. Reactants used in the synthesis were MDI (methylene diphenyl diisocyanate as diisocyanate, DVB (divinylbenzene as crosslinking agent for polystyrene, dibutylamine as redox primer and benzoyl peroxide as styrene polymerisation primer. The variables considered in SIN synthesis were percentage weight ratio used in the modification (1.32%; 2.64% and 5.28% to increase polyol hydroxyl functionality, starch species incorporated into polyol (Brazilian, Venezuelan and commercial to vary the amount of amylopectin within the polyol-suspension, diisocyanate/hydroxyl NCO/OH (0.85 and 1 functional groups’ molar ratio and polyurethane/ polystyrene PU/PS weight ratio (70/30 and 80/20. A wide range of materials was obtained and characterised by tensile strength, hardness, chemical attack and Soxhlet extraction. The physical-mechanical properties of the materials produced with polyols (transesterified castor oil were improved when starch was incorporated into the polyol. Several tests indicated that 24 hours as curing time were not enough, because the SINs showed lower physical-mechanical properties than the homologous polyurethane elastomers did; thus, the curing time had to be increased to 48 hours.

  10. The synthesis and characterisation of MDMA derived from a catalytic oxidation of material isolated from black pepper reveals potential route specific impurities.

    Science.gov (United States)

    Plummer, Christopher M; Breadon, Thomas W; Pearson, James R; Jones, Oliver A H

    2016-05-01

    This work examines the chemical synthesis of 3,4-methylenedioxy-N-methylamphetamine (MDMA) from piperonal prepared via a catalytic ruthenium tetroxide oxidation of piperine extracted from black pepper. A variety of oxidation conditions were experimented with including different solvent systems and co-oxidants. A sample of prepared piperonal was successfully converted into MDMA via 3,4-methylenedioxyphenyl-2-nitropropene (MDP2NP) and 3,4-methylenedioxyphenyl-2-propanone (MDP2P) and the impurities within each product characterised by GC-MS to give a contaminant profile of the synthetic pathway. Interestingly, it was discovered that a chlorinated analogue of piperonal (6-chloropiperonal) was created during the oxidation process by an as yet unknown mechanism. This impurity reacted alongside piperonal to give chlorinated analogues of each precursor, ultimately yielding 2-chloro-4,5-methylenedioxymethamphetamine (6-Cl-MDMA) as an impurity within the MDMA sample. The methodology developed is a simple way to synthesise a substantial amount of precursor material with easy to obtain reagents. The results also show that chlorinated MDMA analogues, previously thought to be deliberately included adulterants, may in fact be route specific impurities with potential application in determining the origin and synthesis method of seized illicit drugs.

  11. Synthesis and Characterisation of the Europium (III Dimolybdo-Enneatungsto-Silicate Dimer, [Eu(α-SiW9Mo2O392]13−

    Directory of Open Access Journals (Sweden)

    Loïc Parent

    2015-07-01

    Full Text Available The chemistry of polyoxometalates (POMs keeps drawing the attention of researchers, since they constitute a family of discrete molecular entities whose features may be easily modulated. Often considered soluble molecular oxide analogues, POMs possess enormous potential due to a myriad of choices concerning size, shape and chemical composition that may be tailored in order to fine-tune their physico-chemical properties. Thanks to the recent progress in single-crystal X ray diffraction, new POMs exhibiting diverse and unexpected structures have been regularly reported and described. We find it relevant to systematically analyse the different equilibria that govern the formation of POMs, in order to be able to establish reliable synthesis protocols leading to new molecules. In this context, we have been able to synthesise the Eu3+-containing silico-molybdo-tungstic dimer, [Eu(α-SiW9Mo2O392]13−. We describe the synthesis and characterisation of this new species by several physico-chemical methods, such as single-crystal X-ray diffraction, 183W NMR and electrochemistry.

  12. The synthesis and characterisation of MDMA derived from a catalytic oxidation of material isolated from black pepper reveals potential route specific impurities.

    Science.gov (United States)

    Plummer, Christopher M; Breadon, Thomas W; Pearson, James R; Jones, Oliver A H

    2016-05-01

    This work examines the chemical synthesis of 3,4-methylenedioxy-N-methylamphetamine (MDMA) from piperonal prepared via a catalytic ruthenium tetroxide oxidation of piperine extracted from black pepper. A variety of oxidation conditions were experimented with including different solvent systems and co-oxidants. A sample of prepared piperonal was successfully converted into MDMA via 3,4-methylenedioxyphenyl-2-nitropropene (MDP2NP) and 3,4-methylenedioxyphenyl-2-propanone (MDP2P) and the impurities within each product characterised by GC-MS to give a contaminant profile of the synthetic pathway. Interestingly, it was discovered that a chlorinated analogue of piperonal (6-chloropiperonal) was created during the oxidation process by an as yet unknown mechanism. This impurity reacted alongside piperonal to give chlorinated analogues of each precursor, ultimately yielding 2-chloro-4,5-methylenedioxymethamphetamine (6-Cl-MDMA) as an impurity within the MDMA sample. The methodology developed is a simple way to synthesise a substantial amount of precursor material with easy to obtain reagents. The results also show that chlorinated MDMA analogues, previously thought to be deliberately included adulterants, may in fact be route specific impurities with potential application in determining the origin and synthesis method of seized illicit drugs. PMID:27162021

  13. Specific glycosylation of α1-acid glycoprotein characterises patients with familial Mediterranean fever and obligatory carriers of MEFV

    NARCIS (Netherlands)

    Poland, D.C.W.; Drenth, J.P.H.; Rabinovitz, E.; Livneh, A.; Bijzet, J.; Van het Hof, B.; Van Dijk, W.

    2001-01-01

    Background - Familial Mediterranean fever (FMF) is a periodic febrile disorder, characterised by fever and serositis. The acute phase response during attacks of FMF results from the release of cytokines, which in turn induce increased expression and changed glycosylation of acute phase proteins. A r

  14. Preparation and structural characterisation of novel and versatile amphiphilic octenyl succinic anhydride-modified hyaluronic acid derivatives

    DEFF Research Database (Denmark)

    Eenschooten, Corinne Diane; Guillaumie, Fanny; Kontogeorgis, Georgios;

    2010-01-01

    and structurally characterised by Fourier transform-infrared spectroscopy and proton nuclear magnetic resonance spectroscopy (1H NMR). The influence of four reaction parameters on the DS of the derivatives was studied by means of an experimental design. The results showed that the OSA/HA molar ratio, the buffer...

  15. Synthesis of a stable gold hydrosol by the reduction of chloroaurate ions by the amino acid, aspartic acid

    Indian Academy of Sciences (India)

    Saikat Mandal; P R Selvakannan; Sumant Phadtare; Renu Pasricha; Murali Sastry

    2002-10-01

    Development of reliable protocols for the synthesis of nanoparticles of well-defined sizes and good monodispersity is an important aspect of nanotechnology. In this paper, we present details of the synthesis of gold nanoparticles of good monodispersity by the reduction of aqueous chloroaurate ions by the amino acid, aspartic acid. The colloidal gold solution thus formed is extremely stable in time, indicating electrostatic stabilization via nanoparticle surface-bound amino acid molecules. This observation has been used to modulate the size of the gold nanoparticles in solution by varying the molar ratio of chloroaurate ions to aspartic acid in the reaction medium. Characterization of the aspartic acid-reduced gold nanoparticles was carried out by UV-visible spectroscopy, thermogravimetric analysis and transmission electron microscopy. The use of amino acids in the synthesis and stabilization of gold nanoparticle in water has important implications in the development of new protocols for generation of bioconjugate materials.

  16. Activity of dietary fatty acids on FFA1 and FFA4 and characterisation of pinolenic acid as a dual FFA1/FFA4 agonist with potential effect against metabolic diseases

    DEFF Research Database (Denmark)

    Christiansen, Elisabeth; Watterson, Kenneth R.; Stocker, Claire J.;

    2015-01-01

    in concentration-response curves. Of the screened compounds, pinolenic acid, a constituent of pine nut oil, was identified as a relatively potent and efficacious dual FFA1/FFA4 agonist, and its suitability for further studies was confirmed by additional in vitro characterisation. Pine nut oil and free...... and esterified pure pinolenic acid were tested in an acute glucose tolerance test in mice. Pine nut oil showed a moderately but significantly improved glucose tolerance compared with maize oil. Pure pinolenic acid or ethyl ester gave robust and highly significant improvements of glucose tolerance. In conclusion...

  17. Expression of fatty acid synthesis genes and fatty acid accumulation in haematococcus pluvialis under different stressors

    Directory of Open Access Journals (Sweden)

    Lei Anping

    2012-03-01

    Full Text Available Abstract Background Biofuel has been the focus of intensive global research over the past few years. The development of 4th generation biofuel production (algae-to-biofuels based on metabolic engineering of algae is still in its infancy, one of the main barriers is our lacking of understanding of microalgal growth, metabolism and biofuel production. Although fatty acid (FA biosynthesis pathway genes have been all cloned and biosynthesis pathway was built up in some higher plants, the molecular mechanism for its regulation in microalgae is far away from elucidation. Results We cloned main key genes for FA biosynthesis in Haematococcus pluvialis, a green microalga as a potential biodiesel feedstock, and investigated the correlations between their expression alternation and FA composition and content detected by GC-MS under different stress treatments, such as nitrogen depletion, salinity, high or low temperature. Our results showed that high temperature, high salinity, and nitrogen depletion treatments played significant roles in promoting microalgal FA synthesis, while FA qualities were not changed much. Correlation analysis showed that acyl carrier protein (ACP, 3-ketoacyl-ACP-synthase (KAS, and acyl-ACP thioesterase (FATA gene expression had significant correlations with monounsaturated FA (MUFA synthesis and polyunsaturated FA (PUFA synthesis. Conclusions We proposed that ACP, KAS, and FATA in H. pluvialis may play an important role in FA synthesis and may be rate limiting genes, which probably could be modified for the further study of metabolic engineering to improve microalgal biofuel quality and production.

  18. Design, Synthesis and Characterisation of Novel Biodegradable Aliphatic Copolyesters- Poly(ethylene sebacate-co-butylene succinate and Poly(ethylene sebacate-co-butylene adipate

    Directory of Open Access Journals (Sweden)

    L. SOWBAGYALAKSHMI PRABHA

    2012-12-01

    Full Text Available Synthesis of novel aliphatic biodegradable copolyesters namely Poly (ethylene sebacate-co-butylene succinate and Poly (ethylene sebacate-co-butylene adipate were carried out using Poly (butylene Succinate, Poly (Butylene Adipate and Poly (Ethylene Sebacate in presence of Poly Phosphoric acid. Synthesis of Poly (Butylene Succinate, Poly (Butylene Adipate and Poly (Ethylene Sebacate were carried out using respective diols and diacids in presence of titanium tetrabutoxide as catalyst. Newly synthesized copolyesters were characterized by solubility studies, viscosity measurements, thermal analysis, IR Spectroscopy and Nuclear Magnetic Resonance Spectroscopy (1H-NMR and 13C-NMR. The characteristic peaks present in the homopolyesters were recorded in the copolymers as well. DSC analysis of the copolyesters showed multiple melting peaks, while increase of methylene units in the di-acid decreased the Tg.

  19. Synthesis, characterisation, stereochemistry and antimicrobial activity of 5 -piperazino- and 5-morpholinoacetyl-2,2,4-trimethyl-1, 5-benzodiazepines

    Indian Academy of Sciences (India)

    S Ponnuswamy; A Akila; D Deepa Rajakumari; V Shreevidhyaa Suressh; G Usha

    2015-11-01

    Three 1,5-benzodiazepines viz., 5-chloroacetyl-, 5-piperazinoacetyl- and N5 -morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepines have been synthesized. The structural characterisation and the conformational preferences of the compounds have been carried out using IR, 1D and 2D NMR spectral data. The NMR spectral data show that the -acetyltetrahydro-1,5-benzodiazepines prefer to exist in boat conformation with exo orientation of >C=O at 5 position in the solution state. The X-ray crystal structure of 5-morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepine also supports boat conformation in the solid state. The antimicrobial activity for -acetyltetrahydro-1,5-benzodiazepines have been carried out. -morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepine demonstrated better antibacterial and antifungal activities.

  20. Synthesis and characterisation of chitosan crosslinked-β-cyclodextrin grafted silylated magnetic nanoparticles for controlled release of Indomethacin

    Science.gov (United States)

    Anirudhan, T. S.; Dilu, D.; Sandeep, S.

    2013-10-01

    In this work, a novel hydrogel, chitosan crosslinked β-cyclodextrin grafted silylated magnetic nanoparticle (CTSCD-g-SilylMNP) was synthesised as a drug delivery system onto which Indomethacin (IND) drug was loaded. Characterisation of the drug delivery system was carried out by Tunnelling electron microscopy, Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, Dynamic light scattering and a Vibrating sample magnetometer. Swelling behaviour, in vitro drug release kinetics, and encapsulation efficiency of CTSCD-g-SilylMNP were studied. Swelling behaviour varied according to pH. In vitro release studies revealed that CTSCD-g-SilylMNP demonstrated a swelling and diffusion controlled release. Dependence of pH was also studied. Encapsulation efficiency (EE) at different percentages of drug loadings was studied. The results collectively suggest that the hydrogel has promising application in the field of controlled drug release. The biodegradability also adds to the advantage.

  1. Synthesis of E. faecium wall teichoic acid fragments.

    Science.gov (United States)

    van der Es, Daan; Groenia, Nadia A; Laverde, Diana; Overkleeft, Herman S; Huebner, Johannes; van der Marel, Gijsbert A; Codée, Jeroen D C

    2016-09-01

    The first synthesis of different Enterococcus faecium wall teichoic acid (WTA) fragments is presented. The structure of these major cell wall components was elucidated recently and it was shown that these glycerolphosphate (GroP) based polymers are built up from -6-(GalNAc-α(1-3)-GalNAc-β(1-2)-GroP)- repeating units. We assembled WTA fragments up to three repeating units in length, in two series that differ in the stereochemistry of the glycerolphosphate moiety. The key GalNAc-GalNAc-GroP synthons, required for the synthesis, were generated from galactosazide building blocks that were employed in highly stereoselective glycosylation reactions to furnish both the α- and β-configured linkages. By comparing the NMR spectra of the synthesized fragments with the isolated material it appears that the hereto undefined stereochemistry of the glycerol phosphate moiety is sn-glycerol-3-phosphate. The generated fragments will be valuable tools to study their immunological activity at the molecular level. PMID:26993744

  2. Enzymatic synthesis and application of fatty acid ascorbyl esters

    Directory of Open Access Journals (Sweden)

    Stojanović Marija M.

    2013-01-01

    Full Text Available Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully used as a reaction medium, since commonly used solvents with high Log P values are inapplicable due to ascorbic acid high polarity. Acylation of vitamin C using fatty acids, their methyl-, ethyl-, and vinyl esters, as well as triglycerides has been performed, whereas application of the activated acyl donors enabled higher molar conversions. In each case, majority of authors reported that using excessive amount of the acyl donor had positive effect on yield of product. Furthermore, several strategies have been employed for shifting the equilibrium towards the product by water content control. These include adjusting the initial water activity by pre-equilibration of reaction mixture, enzyme preparation with water vapor of saturated salt solutions, and the removal of formed water by the addition of molecular sieves or salt hydrate pairs. The aim of this article is to provide a brief overview of the procedures described so far for the lipase-catalyzed synthesis of fatty acid ascorbyl esters with emphasis on the potential application in food, cosmetics, and pharmaceutics. Furthermore, it has been pointed out that the main obstacles for process commercialization are long reaction times, lack of adequate purification methods, and high costs of lipases. Thus, future challenges in this area are testing new catalysts, developing continuous processes for esters production, finding cheaper acyl donors and reaction mediums, as well as identifying standard procedures for

  3. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    OpenAIRE

    Xuezheng Liang; Shao-Qin Lv; Lin-Mei Rong; Sheng-Xian Zhao; Chunqing Li; Baowei Hu; Chenze Qi

    2010-01-01

    The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols ...

  4. Synthesis, Characterisation, and Biological Evaluation of Zn(II) Complex with Tridentate (NNO Donor) Schiff Base Ligand

    OpenAIRE

    Ahmed, Nayaz; Riaz, Mohd; Ahmed, Altaf; Bhagat, Madhulika

    2015-01-01

    The present paper deals with the synthesis and characterization of metal complex of tridentate Schiff base ligand derived from the inserted condensation of 2-aminobenzimidazole (1H-benzimidazol-2-amine) with salicylaldehyde (2-hydroxybenzaldehyde) in a 1 : 1 molar ratio. Using this tridentate ligand, complex of Zn(II) with general formula ML has been synthesized. The synthesized complex was characterized by several techniques using molar conductance, elemental analysis, FT-IR, and mass and 1H...

  5. PMo or PW heteropoly acids supported on MCM-41 silica nanoparticles: Characterisation and FT-IR study of the adsorption of 2-butanol

    International Nuclear Information System (INIS)

    Mesoporous silica, prepared in basic conditions, has been loaded (20% weight) with 12-molybdophosphoric (PMo) or 12-tungstophosphoric (PW) acid and calcined at different temperatures ranging between 250 and 550 deg. C. The samples have been characterised by N2 adsorption-desorption at -196 deg. C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), UV-visible diffuse reflectance, Raman spectroscopy and temperature programmed reduction (TPR). The acidity and catalytic activity have been, respectively, examined by monitoring the adsorption of pyridine and 2-butanol by FT-IR spectroscopy. The results indicate that PW and PMo acids are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles. While PMo retains its Keggin structure up to 550 deg. C, PW decomposes at this temperature into crystalline WO3 and phosphorous oxides. In both cases, the morphology, hexagonal symmetry and long-range order observed for the support are preserved with calcination up to 450 deg. C. The Broensted-type acid sites found in all samples, whose surface concentration decreases as the calcination temperature increases, are responsible for the selective formation of cis-butene detected upon adsorption of 2-butanol. The sample containing PW calcined at 450 deg. C also shows selectivity to methyl ethyl ketone. - Graphical abstract: Samples based in MCM-41 nanoparticles loaded with tungstophosphoric and molybdophosphoric acids have been synthesised. The uncalcined solids and that derived upon their calcination in the temperature range 250-550 deg. C have been characterised and evaluated in the decomposition of 2-butanol monitored by FT-IR spectroscopy

  6. Characterisation of PDO olive oil Chianti Classico by non-selective (UV-visible, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Casale, M., E-mail: monica@dictfa.unige.it [Universita degli Studi di Genova, Department of Chemistry and Food and Pharmaceutical Technologies, Via Brigata Salerno 13, I-16147, Genoa (Italy); Oliveri, P.; Casolino, C. [Universita degli Studi di Genova, Department of Chemistry and Food and Pharmaceutical Technologies, Via Brigata Salerno 13, I-16147, Genoa (Italy); Sinelli, N. [Universita degli Studi di Milano, Department of Food Science and Technology, Via Celoria, 2 - I-20133 Milan (Italy); Zunin, P.; Armanino, C.; Forina, M.; Lanteri, S. [Universita degli Studi di Genova, Department of Chemistry and Food and Pharmaceutical Technologies, Via Brigata Salerno 13, I-16147, Genoa (Italy)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Characterisation of the Italian PDO extra virgin olive oil Chianti Classico. Black-Right-Pointing-Pointer Comparison between non-selective (UV-vis, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques. Black-Right-Pointing-Pointer Synergy among spectroscopic techniques, by the fusion of the respective spectra. Black-Right-Pointing-Pointer Prediction of the content of oleic and linoleic acids in the olive oils. - Abstract: An authentication study of the Italian PDO (protected designation of origin) extra virgin olive oil Chianti Classico was performed; UV-visible (UV-vis), Near-Infrared (NIR) and Mid-Infrared (MIR) spectroscopies were applied to a set of samples representative of the whole Chianti Classico production area. The non-selective signals (fingerprints) provided by the three spectroscopic techniques were utilised both individually and jointly, after fusion of the respective profile vectors, in order to build a model for the Chianti Classico PDO olive oil. Moreover, these results were compared with those obtained by the gas chromatographic determination of the fatty acids composition. In order to characterise the olive oils produced in the Chianti Classico PDO area, UNEQ (unequal class models) and SIMCA (soft independent modelling of class analogy) were employed both on the MIR, NIR and UV-vis spectra, individually and jointly, and on the fatty acid composition. Finally, PLS (partial least square) regression was applied on the UV-vis, NIR and MIR spectra, in order to predict the content of oleic and linoleic acids in the extra virgin olive oils. UNEQ, SIMCA and PLS were performed after selection of the relevant predictors, in order to increase the efficiency of both classification and regression models. The non-selective information obtained from UV-vis, NIR and MIR spectroscopy allowed to build reliable models for checking the authenticity of the Italian PDO extra virgin olive oil

  7. Characterisation of PDO olive oil Chianti Classico by non-selective (UV–visible, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques

    International Nuclear Information System (INIS)

    Highlights: ► Characterisation of the Italian PDO extra virgin olive oil Chianti Classico. ► Comparison between non-selective (UV–vis, NIR and MIR spectroscopy) and selective (fatty acid composition) analytical techniques. ► Synergy among spectroscopic techniques, by the fusion of the respective spectra. ► Prediction of the content of oleic and linoleic acids in the olive oils. - Abstract: An authentication study of the Italian PDO (protected designation of origin) extra virgin olive oil Chianti Classico was performed; UV–visible (UV–vis), Near-Infrared (NIR) and Mid-Infrared (MIR) spectroscopies were applied to a set of samples representative of the whole Chianti Classico production area. The non-selective signals (fingerprints) provided by the three spectroscopic techniques were utilised both individually and jointly, after fusion of the respective profile vectors, in order to build a model for the Chianti Classico PDO olive oil. Moreover, these results were compared with those obtained by the gas chromatographic determination of the fatty acids composition. In order to characterise the olive oils produced in the Chianti Classico PDO area, UNEQ (unequal class models) and SIMCA (soft independent modelling of class analogy) were employed both on the MIR, NIR and UV–vis spectra, individually and jointly, and on the fatty acid composition. Finally, PLS (partial least square) regression was applied on the UV–vis, NIR and MIR spectra, in order to predict the content of oleic and linoleic acids in the extra virgin olive oils. UNEQ, SIMCA and PLS were performed after selection of the relevant predictors, in order to increase the efficiency of both classification and regression models. The non-selective information obtained from UV–vis, NIR and MIR spectroscopy allowed to build reliable models for checking the authenticity of the Italian PDO extra virgin olive oil Chianti Classico.

  8. Reviewing the Tannic Acid Mediated Synthesis of Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tufail Ahmad

    2014-01-01

    Full Text Available Metal nanoparticles harbour numerous exceptional physiochemical properties absolutely different from those of bulk metal as a function of their extremely small size and large superficial area to volume. Naked metal nanoparticles are synthesized by various physical and chemical methods. Chemical methods involving metal salt reduction in solution enjoy an extra edge over other protocols owing to their relative facileness and capability of controlling particle size along with the attribute of surface tailoring. Although chemical methods are the easiest, they are marred by the use of hazardous chemicals such as borohydrides. This has led to inclination of scientific community towards eco-friendly agents for the reduction of metal salts to form nanoparticles. Tannic acid, a plant derived polyphenolic compound, is one such agent which embodies characteristics of being harmless and environmentally friendly combined with being a good reducing and stabilizing agent. In this review, first various methods used to prepare metal nanoparticles are highlighted and further tannic acid mediated synthesis of metal nanoparticles is emphasized. This review brings forth the most recent findings on this issue.

  9. Inhibition of fatty acid synthesis in rat hepatocytes by exogenous polyunsaturated fatty acids is caused by lipid peroxidation

    DEFF Research Database (Denmark)

    Mikkelsen, L.; Hansen, Harald S.; Grunnet, N.;

    1993-01-01

    by the peroxidized PUFA. Arachidonic acid and eicosapentaenoic acid showed a dose- and time-dependent cytotoxicity. Two other antioxidants: 50 µM a-tocopherol acid succinate and 1 µM N,N'-diphenyl-1,4-phenylenediamine, both proved more efficient than a-tocopherol phosphate. There was a significant correlation......Rat hepatocyte long-term cultures were utilized to investigate the impact of different polyunsaturated fatty acids (PUFA) on the insulin-induced de novo fatty acid synthesis in vitro. The addition of 0.5 mM albumin-complexed oleic, linoleic, columbinic, arachidonic, eicosapentaenoic...... or docosahexaenoic acid resulted in a marked suppression of fatty acid synthesis. By evaluation of cell viability (determined as the leakage of lactate dehydrogenase (LDH)) it turned our, that the antioxidant used (50 µM a-tocopherol phosphate) had a low antioxidant activity, resulting in cytotoxic effects...

  10. Inhibition of Interjacent Ribonucleic Acid (26S) Synthesis in Cells Infected by Sindbis Virus

    Science.gov (United States)

    Scheele, Christina M.; Pfefferkorn, E. R.

    1969-01-01

    The interrelationship of viral ribonucleic acid (RNA) and protein synthesis in cells infected by Sindbis virus was investigated. When cultures were treated with puromycin early in the course of infection, the synthesis of interjacent RNA (26S) was preferentially inhibited. A similar result was obtained by shifting cells infected by one temperature-sensitive mutant defective in RNA synthesis from the permissive (29 C) to the nonpermissive (41.5 C) temperature. Under both conditions, the viral RNA produced appeared to be fully active biologically. Once underway, the synthesis of viral RNA in wild-type Sindbis infections did not require concomitant protein synthesis. PMID:5817400

  11. Synthesis, spectral characterisation, morphology, biological activity and DNA cleavage studies of metal complexes with chromone Schiff base

    Directory of Open Access Journals (Sweden)

    P. Kavitha

    2016-07-01

    Full Text Available Cu(II, Co(II, Ni(II and Zn(II complexes have been synthesized using 3-((pyridine-2-yliminomethyl-4H-chromen-4-one as a ligand derived from 3-formyl chromone and 2-amino pyridine. All the complexes were characterised by analytical, conductivity, IR, electronic, magnetic, ESR, thermal, powder XRD and SEM studies. The analytical data revealed that the metal to ligand molar ratio is 1:2 in all the complexes. Molar conductivity data indicates that all the complexes are neutral in nature. On the basis of magnetic and electronic spectral data, octahedral geometry is proposed for all the complexes. Thermal behaviour of the synthesized complexes indicates the coordinated and lattice water molecules are present in the complexes. The X-ray diffraction data suggest a triclinic system for all compounds. Different surface morphologies were identified from SEM micrographs. All metal complexes exhibit fluorescence. The antimicrobial and nematicidal activity data show that metal complexes are more potent than the parent ligand. The DNA cleavage activity of the ligand and its metal complexes were observed in the presence of H2O2.

  12. Synthesis, characterisation of few N-substituted 1,8-naphthalimide derivatives and their copper(II) complexes

    Indian Academy of Sciences (India)

    Nilotpal Barooah; Chandan Tamuly; Jubaraj B Baruah

    2005-03-01

    A few 1,8-naphthalimide derivatives with phenyl (1), benzyl (2), 3,4-dimethoxyphenyl ethyl (3), 4-pyridyl (4), 2-hydroxy ethyl (5), 4-pyridylmethyl (6) groups attached to the nitrogen atom are synthesized and characterized. Cyclic voltammograms of all these compounds show one-electron reversible redox cycle (-1.24 V to -1.18 V) due to formation of anion radicals. However, in the case of (5), quenching of this redox process occurs when polyhydroxy-aromatic compounds such as 1,3-dihydroxy benzene and 1,3,5-trihydroxybenzene are added. Copper complexes, namely bis-{N-(4-pyridylmethyl)1,8-naphthalimide}copper (II) perchlorate (8), bis-{N-(4-pyridylmethyl)1,8-naphthalimide}copper (II) perchlorate (9) and bis-{N-(4-pyridylmethyl)phthalimide} copper (II) perchlorate (10) are synthesized and characterised. The complexes (8) and (9) show reversible redox couple of the ligand without any significant interaction with the redox active copper (II) centre.

  13. Synthesis and characterisation of chitosan crosslinked-β-cyclodextrin grafted silylated magnetic nanoparticles for controlled release of Indomethacin

    Energy Technology Data Exchange (ETDEWEB)

    Anirudhan, T.S., E-mail: tsani@rediffmail.com; Dilu, D.; Sandeep, S.

    2013-10-15

    In this work, a novel hydrogel, chitosan crosslinked β-cyclodextrin grafted silylated magnetic nanoparticle (CTSCD-g-SilylMNP) was synthesised as a drug delivery system onto which Indomethacin (IND) drug was loaded. Characterisation of the drug delivery system was carried out by Tunnelling electron microscopy, Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, Dynamic light scattering and a Vibrating sample magnetometer. Swelling behaviour, in vitro drug release kinetics, and encapsulation efficiency of CTSCD-g-SilylMNP were studied. Swelling behaviour varied according to pH. In vitro release studies revealed that CTSCD-g-SilylMNP demonstrated a swelling and diffusion controlled release. Dependence of pH was also studied. Encapsulation efficiency (EE) at different percentages of drug loadings was studied. The results collectively suggest that the hydrogel has promising application in the field of controlled drug release. The biodegradability also adds to the advantage. - Highlights: • A novel hydrogel chitosan crosslinked β-cyclodextrin grafted silylated magnetic nanoparticles (CTS–CD-g-SilylMNP) were synthesised. • Chitosan would increase the biocompatibility and swellability of the material. • Indomethacin drug was loaded onto CTS–CD-g-SilylMNP. • The swelling behaviour,drug release and encapsulation efficiency of the hydrogel were studied. • CTS–CD-g-SilylMNP can be used as a promising drug delivery system.

  14. Synthesis and application of acid labile anchor groups for the synthesis of peptide amides by Fmoc-solid-phase peptide synthesis.

    Science.gov (United States)

    Breipohl, G; Knolle, J; Stüber, W

    1989-10-01

    The preparation and application of a new linker for the synthesis of peptide amides using a modified Fmoc-method is described. The new anchor group was developed based on our experience with 4,4'-dimethoxybenzhydryl (Mbh)-protecting group for amides. Lability towards acid treatment was increased dramatically and results in an easy cleavage procedure for the preparation of peptide amides. The synthesis of N-9-fluorenylmethoxycarbonyl- ([5-carboxylatoethyl-2.4-dimethoxyphenyl)- 4'-methoxyphenyl]-methylamin is reported in detail. This linker was coupled to a commercially available aminomethyl polystyrene resin. Peptide synthesis proceeded smoothly using HOOBt esters of Fmoc-amino acids. Release of the peptide amide and final cleavage of the side chain protecting groups was accomplished by treatment with trifluoroacetic acid-dichloromethane mixtures in the presence of scavengers. The synthesis of peptide amides such as LHRH and C-terminal hexapeptide of secretin are given as examples.

  15. Amino Acid Synthesis in Seafloor Environments on Icy Worlds

    Science.gov (United States)

    Flores, Erika; Barge, Laura; VanderVelde, David; Kallas, Kayo; Baum, Marc M.; Russell, Michael J.; Kanik, Isik

    2016-10-01

    In 2005, the Cassini mission detected plumes erupting from Enceladus' surface, containing carbon dioxide, methane, silica, and possibly ammonia. Subsequent laboratory experiments indicated that the silica particles in the plumes were generated under alkaline conditions and at moderate temperatures of ~90°C (Hsu et al., 2015); one scenario for such conditions would be the existence of alkaline (serpentinization-driven) hydrothermal activity within Enceladus. Alkaline vents are significant since they have been proposed as a likely environment for the emergence of metabolism on the early Earth (Russell et al. 2014) and thus could also provide a mechanism for origin of life on ocean worlds with a water-rock interface. Alkaline vents in an acidic, iron-containing ocean could produce mineral precipitates that could act as primitive enzymes or catalysts mediating organic reactions; for example, metal sulfides can catalyze the reductive amination of pyruvate to alanine (Novikov and Copley 2013). We have conducted experiments testing the synthesis of amino acids catalyzed by other iron minerals that might be expected to precipitate on the seafloor of early Earth or Enceladus. Preliminary results indicate that amino acids as well as other organic products can be synthesized in 1-3 days under alkaline hydrothermal conditions. We also find that the yield and type of organic products is highly dependent on pH and temperature, implying that understanding the specifics of the geochemical hydrothermal gradients on Enceladus (or other ocean worlds) will be significant in determining their potential for synthesizing building blocks for life.Hsu, H.-W. et al. (2015), Nature 519, 207-210.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Novikov Y. and Copley S. D. (2013) PNAS 110, 33, 13283-13288.

  16. Ceramide synthesis from free fatty acids in rat brain: function of NADPH and substrate specificity

    Energy Technology Data Exchange (ETDEWEB)

    Singh, I.

    1983-06-01

    At the subcellular level, the synthesis of ceramide from free lignoceric acid and sphingosine in brain required reconstituted enzyme system (particulate fraction, heat-stable and heat-labile factors) and pyridine nucleotide (NADPH). The mitochondrial electron transfer inhibitors (KCN and antimycin A), energy uncouplers (oligomycin and 2,4-dinitrophenol), and carboxyatractyloside, which prevents the transport of ATP and ADP through the mitochondrial wall, inhibit the synthesis of ceramide in the presence of NADPH but have very little effect in the presence of ATP. Similar to the synthesis of ceramide, the synthesis of ATP from NADPH and NADH by the particulate fraction also required cytoplasmic factors (heat-stable and heat-labile factors). Moreover, ATP, but not its analog (AMP-CH2-P-O-P), can replace NADPH, thus suggesting that the function of the pyridine nucleotide is to provide ATP for the synthesis of ceramide. The cytoplasmic factors were not required for the synthesis of ceramide in the presence of ATP. The maximum velocity for synthesis of ceramide from free fatty acids of different chain lengths (C16-C26) was bimodal, with maxima around stearic acid (C18) and behenic acid (C22). The relative rate of synthesis of ceramide parallels the relative distribution of these fatty acids in brain cerebrosides and sulfatides.

  17. Soluble Polymer-Supported Synthesis of α-Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    XIE Cheng; HU Chun-Ling; ZHANG Gang-Shen; CHEN Zu-Xing

    2003-01-01

    @@ Due to the central role played by α-amino acid in chemistry and biology, the development of versatile and new methodology for the synthesis of natural and unnatural α-amino acid has emerged as an important and challenging synthetic endeavour for organic chemists.[1] Among the various methodologies reported for α-amino acid synthesis, [2,3] the solid-phase organic synthesis (SPOS) has served as an important approach. [4] However, inherent prob lems on solid supports are reactive site accessibility, site-site interaction and monitoring of the reaction.

  18. Leuconostoc citreum SK24.002 glucansucrase: Biochemical characterisation and de novo synthesis of α-glucan.

    Science.gov (United States)

    Song, Liping; Miao, Ming; Jiang, Bo; Xu, Ting; Cui, Steve W; Zhang, Tao

    2016-10-01

    The cell-associated glucansucrase from Leuconostoc citreum SK24.002 was isolated, purified, characterized and used for de novo synthesis of α-glucan and acceptor-products. The final specific glucansucrase activity was 1.4U/mg protein with 13.2-fold purification. The obtained glucansucrase had a molecular weight of 186kDa,Tm of 61.7 °C and △H of 176.7kJ/mol. The enzyme showed maximum activity at pH 5.0-6.0 and 45°C. The enzyme activity was enhanced by Ca(2+), Mn(2+) or Co(2+) ions, whereas the activity decreased as the methanol, ethanol, n-butanol, DMSO or isopropanol concentration increased. The chemical inhibitors including BD, DTNB, EDC or NBS also significantly inhibited enzyme activity. Km, Vmax and kcat of glucansucrase were 10.9mM, 3.6U/mg and 306.6 1/s, respectively. For de novo synthesis from sucrose, α-glucan polymer with molecular weight of 1.5×10(7)g/mol and maltose acceptor products (trisaccharide, tetrasaccharide and pentasaccharide) were obtained by glucansucrase via glucosyltransfer reactions, respectively. PMID:27164499

  19. Synthesis of L-ascorbic acid in the phloem

    Directory of Open Access Journals (Sweden)

    Haupt Sophie

    2003-11-01

    Full Text Available Abstract Background Although plants are the main source of vitamin C in the human diet, we still have a limited understanding of how plants synthesise L-ascorbic acid (AsA and what regulates its concentration in different plant tissues. In particular, the enormous variability in the vitamin C content of storage organs from different plants remains unexplained. Possible sources of AsA in plant storage organs include in situ synthesis and long-distance transport of AsA synthesised in other tissues via the phloem. In this paper we examine a third possibility, that of synthesis within the phloem. Results We provide evidence for the presence of AsA in the phloem sap of a wide range of crop species using aphid stylectomy and histochemical approaches. The activity of almost all the enzymes of the primary AsA biosynthetic pathway were detected in phloem-rich vascular exudates from Cucurbita pepo fruits and AsA biosynthesis was demonstrated in isolated phloem strands from Apium graveolens petioles incubated with a range of precursors (D-glucose, D-mannose, L-galactose and L-galactono-1,4-lactone. Phloem uptake of D-[U-14C]mannose and L-[1-14C]galactose (intermediates of the AsA biosynthetic pathway as well as L-[1-14C]AsA and L-[1-14C]DHA, was observed in Nicotiana benthamiana leaf discs. Conclusions We present the novel finding that active AsA biosynthesis occurs in the phloem. This process must now be considered in the context of mechanisms implicated in whole plant AsA distribution. This work should provoke studies aimed at elucidation of the in vivo substrates for phloem AsA biosynthesis and its contribution to AsA accumulation in plant storage organs.

  20. Tailored fatty acid synthesis via dynamic control of fatty acid elongation.

    Science.gov (United States)

    Torella, Joseph P; Ford, Tyler J; Kim, Scott N; Chen, Amanda M; Way, Jeffrey C; Silver, Pamela A

    2013-07-01

    Medium-chain fatty acids (MCFAs, 4-12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even- and odd-chain-length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, thereby slowing acyl-ACP elongation and redirecting flux from phospholipid synthesis to MCFA production. Our results show that induced protein degradation can be used to dynamically alter metabolic flux, and thereby increase the yield of a desired compound. The strategy reported herein should be widely useful in a range of metabolic engineering applications in which essential enzymes divert flux away from a desired product, as well as in the production of polyketides, bioplastics, and other recursively synthesized hydrocarbons for which chain-length control is desired. PMID:23798438

  1. Tailored fatty acid synthesis via dynamic control of fatty acid elongation

    Energy Technology Data Exchange (ETDEWEB)

    Torella, JP; Ford, TJ; Kim, SN; Chen, AM; Way, JC; Silver, PA

    2013-07-09

    Medium-chain fatty acids (MCFAs, 4-12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even-and odd-chain-length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, thereby slowing acyl-ACP elongation and redirecting flux from phospholipid synthesis to MCFA production. Our results show that induced protein degradation can be used to dynamically alter metabolic flux, and thereby increase the yield of a desired compound. The strategy reported herein should be widely useful in a range of metabolic engineering applications in which essential enzymes divert flux away from a desired product, as well as in the production of polyketides, bioplastics, and other recursively synthesized hydrocarbons for which chain-length control is desired.

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

    International Nuclear Information System (INIS)

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

  3. Fatty acid digestion, synthesis and metabolism in broiler chickens and pigs

    NARCIS (Netherlands)

    Smink, W.

    2012-01-01


    The impact of variation in the composition of dietary fat on digestion, metabolism and synthesis of fatty acids was studied in broiler chickens and in pigs. In young broiler chickens, digestion of unsaturated fatty acids was substantially higher compared with that of saturated fatty acids. Po

  4. Synthesis, characterisation and thermal degradation behaviour of some coordination polymers by using TG–DTG and DTA techniques

    Directory of Open Access Journals (Sweden)

    Ratiram Gomaji Chaudhary

    2015-07-01

    Full Text Available The four chelate polymer complexes commonly called as coordination polymers of Mn(II, Co(II, Ni(II and Cu(II ions with fbpmpc (fbpmpc = fumaroyl bis (paramethoxyphenylcarbamide were synthesized and characterised by elemental analyses, infrared spectroscopy, diffuse reflectance, magnetic moment susceptibility, thermal analysis, X-ray diffraction, electrical conductivity and scanning electron microscopy technique (SEM. SEM investigations of coordination polymers were found in different shapes and sizes, though they are synthesized from a single ligand. Each metal ion is coordinated by a bis (bidentate manner through oxygen atom of the carboxylato group and the nitrogen atom of an amide group of ligand and two aqua ligands by coordinated bond which formed 6-member heterocyclic ring. In the present article, the main aim of research study is to find out the comparative studies of coordination polymers such as thermogravimetry (TG, derivative thermogravimetry (DTG, differential thermal analysis (DTA, electrical conductivity and morphology behaviour. Furthermore, the electrical conductivities of chelating ligand and coordination polymers were determined in the solid state powder form. The electrical conductivities measurements of undoped and doped ligand, coordination polymers were carried out at room temperature by the four probe technique using an electrometer. Thermal degradation studies of the coordination polymers have been carried out from a non-isothermal condition under nitrogen atmosphere at a heating rate of 10 °C min−1. The decomposition steps and thermal stabilities of these complexes were confirmed by thermal analysis techniques (TG/DTG/DTA. The thermal studies inferred the presence of crystallized water in all coordination polymers, whereas coordinated water was found in Ni(II and Cu(II ions.

  5. Thioacetic acid/NaSH-mediated synthesis of N-protected amino thioacids and their utility in peptide synthesis.

    Science.gov (United States)

    Mali, Sachitanand M; Gopi, Hosahudya N

    2014-03-21

    Thioacids are recently gaining momentum due to their versatile reactivity. The reactivity of thioacids has been widely explored in the selective amide/peptide bond formation. Thioacids are generally synthesized from the reaction between activated carboxylic acids such as acid chlorides, active esters, etc., and Na2S, H2S, or NaSH. We sought to investigate whether the versatile reactivity of the thioacids can be tuned for the conversion of carboxylic acids into corresponding thioacids in the presence of NaSH. Herein, we report that thioacetic acid- and NaSH-mediated synthesis of N-protected amino thioacids from the corresponding N-protected amino acids, oxidative dimerization of thioacids, crystal conformations of thioacid oxidative dimers, and the utility of thioacids and oxidative dimers in peptide synthesis. Our results suggest that peptides can be synthesized without using standard coupling agents.

  6. Synthesis of a pseudo-disaccharide library and its application to the characterisation of the heparanase catalytic site.

    Science.gov (United States)

    Vinader, Victoria; Haji-Abdullahi, Mohamed H; Patterson, L H; Afarinkia, Kamyar

    2013-01-01

    A novel methodology is described for the efficient and divergent synthesis of pseudodisaccharides, molecules comprising of amino carbasugar analogues linked to natural sugars. The methodology is general and enables the introduction of diversity both at the carbasugar and the natural sugar components of the pseudodisaccharides. Using this approach, a series of pseudodisaccharides are synthesised that mimic the repeating backbone unit of heparan sulfate, and are tested for inhibition of heparanase, a disease-relevant enzyme that hydrolyses heparan sulfate. A new homology model of human heparanase is described based on a family 79 β-glucuronidase. This model is used to postulate a computational rationale for the observed activity of the different pseudodisaccharides and provide valuable information that informs the design of potential inhibitors of this enzyme. PMID:24260588

  7. Synthesis of a pseudo-disaccharide library and its application to the characterisation of the heparanase catalytic site.

    Directory of Open Access Journals (Sweden)

    Victoria Vinader

    Full Text Available A novel methodology is described for the efficient and divergent synthesis of pseudodisaccharides, molecules comprising of amino carbasugar analogues linked to natural sugars. The methodology is general and enables the introduction of diversity both at the carbasugar and the natural sugar components of the pseudodisaccharides. Using this approach, a series of pseudodisaccharides are synthesised that mimic the repeating backbone unit of heparan sulfate, and are tested for inhibition of heparanase, a disease-relevant enzyme that hydrolyses heparan sulfate. A new homology model of human heparanase is described based on a family 79 β-glucuronidase. This model is used to postulate a computational rationale for the observed activity of the different pseudodisaccharides and provide valuable information that informs the design of potential inhibitors of this enzyme.

  8. Optimisation and Characterisation of Lipase-Catalysed Synthesis of a Kojic Monooleate Ester in a Solvent-Free System by Response Surface Methodology.

    Directory of Open Access Journals (Sweden)

    Khairulazhar Jumbri

    Full Text Available Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM based on central composite rotatable design (CCRD was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435 as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield. The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost.

  9. Synthesis of functionalized fluorescent gold nanoclusters for acid phosphatase sensing

    Science.gov (United States)

    Sun, Jian; Yang, Fan; Yang, Xiurong

    2015-10-01

    A novel and convenient one-pot but two-step synthesis of fluorescent gold nanoclusters, incorporating glutathione (GSH) and 11-mercaptoundecanoic acid (MUA) as the functionalized ligands (i.e. AuNCs@GSH/MUA), is demonstrated. Herein, the mixing of HAuCl4 and GSH in aqueous solution results in the immediate formation of non-fluorescent GSH-Au+ complexes, and then a class of ~2.6 nm GSH-coated AuNCs (AuNCs@GSH) with mild orange-yellow fluorescence after several days. Interestingly, the intense orange-red emitting ~1.7 nm AuNCs@GSH/MUA can be synthesized within seconds by introducing an alkaline aqueous solution of MUA into the GSH-Au+ complexes or AuNC@GSH solution. Subsequently, a reliable AuNC@GSH/MUA-based real-time assay of acid phosphatase (ACP) is established for the first time, inspired by the selective coordination of Fe3+ with surface ligands of AuNCs, the higher binding affinity between the pyrophosphate ion (PPi) and Fe3+, and the hydrolysis of PPi into orthophosphate by ACP. Our fluorescent chemosensor can also be applied to assay ACP in a real biological sample and, furthermore, to screen the inhibitor of ACP. This report paves a new avenue for synthesizing AuNCs based on either the bottom-up reduction or top-down etching method, establishing real-time fluorescence assays for ACP by means of PPi as the substrate, and further exploring the sensing applications of fluorescent AuNCs.A novel and convenient one-pot but two-step synthesis of fluorescent gold nanoclusters, incorporating glutathione (GSH) and 11-mercaptoundecanoic acid (MUA) as the functionalized ligands (i.e. AuNCs@GSH/MUA), is demonstrated. Herein, the mixing of HAuCl4 and GSH in aqueous solution results in the immediate formation of non-fluorescent GSH-Au+ complexes, and then a class of ~2.6 nm GSH-coated AuNCs (AuNCs@GSH) with mild orange-yellow fluorescence after several days. Interestingly, the intense orange-red emitting ~1.7 nm AuNCs@GSH/MUA can be synthesized within seconds by

  10. Sulfanilic acid catalyzed solvent-free synthesis of 1,5-benzodiazepine derivatives

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Sulfanilic acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepines from o-phenylenediamine and ketones. This method is simple, effective and environmentally friendly and gives better yields.

  11. Synthesis and characterisation of polyelectrolytes based on polymers of diallyldimethyl ammonium chloride and poly(styrene-co-butadiene)

    OpenAIRE

    Svensson, David

    2012-01-01

    In printed electronics there are many polyelectrolytes to choose from. While polyelectrolytes such as polystyrene sulfonic acid can fulfill many ofthe desired functionalities of a semiconductor, there is a need for other polyelectrolytes with other functionalities, such as functionality at low airhumidity and better cross-linking possibilities, while still functioning as a good semiconductor.Within this thesis, there is a description of general polyelectrolytes, as well as various usages.The ...

  12. Cetalox and analogues: synthesis via acid-mediated polyene cyclizations.

    Science.gov (United States)

    Snowden, Roger L

    2008-06-01

    Using a novel, acid-mediated cyclization methodology, a direct access to Cetalox ((+/-)-1; a commercially important ambergris-type odorant) and various structurally related didehydro (i.e., 19, 26, and 30) and tetradehydro (i.e., 28 and 37/38) analogues is described. Treatment of either (E,E)-14 or (E)-15 with an excess of FSO(3)H in 2-nitropropane at -90 degrees stereospecifically afforded (+/-)-1 in 40 and 42% yield, respectively. Under similar conditions, cyclization of (E)-18 or 20 furnished 19 in 60 and 64% yield, respectively. Analogously, using an excess of ClSO(3)H in CH(2)Cl(2) at -80 degrees, 26 is formed with high stereoselectivity by cyclization of either (E)-24 or (Z)-25 (52 and 31% yield, resp.); in the same manner, 28 was prepared from 27 (22% yield). The same principle was applied to the synthesis of racemic Superambrox (30), via cyclization of 35, but only with poor selectivity (22%) and low yield (7%). Another approach via cyclization of (E)-40 under solvolysis conditions (excess TFA in CH(2)Cl(2) at -10 degrees) gave a higher yield (15%) with improved selectivity (43%). Finally, cyclization of 34 (1:1 diastereoisomer mixture) afforded 37/38 (10:1) in 27% yield. The qualitative organoleptic properties of 19, 26, 28, 30, and 37/38 (10:1) are briefly discussed. PMID:18618391

  13. Synthesis of stable C-linked ferrocenyl amino acids and their use in solution-phase peptide synthesis.

    Science.gov (United States)

    Philip, Anijamol T; Chacko, Shibin; Ramapanicker, Ramesh

    2015-12-01

    Incorporation of ferrocenyl group to peptides is an efficient method to alter their hydrophobicity. Ferrocenyl group can also act as an electrochemical probe when incorporated onto functional peptides. Most often, ferrocene is incorporated onto peptides post-synthesis via amide, ester or triazole linkages. Stable amino acids containing ferrocene as a C-linked side chain are potentially useful building units for the synthesis of ferrocene-containing peptides. We report here an efficient route to synthesize ferrocene-containing amino acids that are stable and can be used in peptide synthesis. Coupling of 2-ferrocenyl-1,3-dithiane and iodides derived from aspartic acid or glutamic acid using n-butyllithium leads to the incorporation of a ferrocenyl unit to the δ-position or ε-position of an α-amino acid. The reduction or hydrolysis of the dithiane group yields an alkyl or an oxo derivative. The usability of the synthesized amino acids is demonstrated by incorporating one of the amino acids in both C-terminus and N-terminus of tripeptides in solution phase.

  14. Synthesis of an Ursolic Acid Saponin with N-Acetylglucosamine-containing Trisaccharide Residue

    Institute of Scientific and Technical Information of China (English)

    WANG Peng; LI Chun-Xia; WANG Guang-Fa; LI Ying-Xia

    2006-01-01

    The focus of this work is the synthesis of an ursolic acid saponin with an N-acetylglucosamine-containing trisaccharide residue. Therefore, ursolic acid 3-yl α-L-arabinopyranosyl-(1→2)-α-L-arabinopyranosyl-(1→6)-2-acetamido-2-deoxy-β-D-glucopyranoside (1) was concisely synthesized in convergent synthesis with 48.0% overall yield. The structure of saponin 1 was confirmed by 1H NMR, 13C NMR and mass spectra.

  15. WRINKLED1 Rescues Feedback Inhibition of Fatty Acid Synthesis in Hydroxylase-Expressing Seeds1[OPEN

    Science.gov (United States)

    Browse, John

    2016-01-01

    Previous attempts at engineering Arabidopsis (Arabidopsis thaliana) to produce seed oils containing hydroxy fatty acids (HFA) have resulted in low yields of HFA compared with the native castor (Ricinus communis) plant and caused undesirable effects, including reduced total oil content. Recent studies have led to an understanding of problems involved in the accumulation of HFA in oils of transgenic plants, which include metabolic bottlenecks and a decrease in the rate of fatty acid synthesis. Focusing on engineering the triacylglycerol assembly mechanisms led to modest increases in the HFA content of seed oil, but much room for improvement still remains. We hypothesized that engineering fatty acid synthesis in the plastids to increase flux would facilitate enhanced total incorporation of fatty acids, including HFA, into seed oil. The transcription factor WRINKLED1 (WRI1) positively regulates the expression of genes involved in fatty acid synthesis and controls seed oil levels. We overexpressed Arabidopsis WRI1 in seeds of a transgenic line expressing the castor fatty acid hydroxylase. The proportion of HFA in the oil, the total HFA per seed, and the total oil content of seeds increased to an average of 20.9%, 1.26 µg, and 32.2%, respectively, across five independent lines, compared with 17.6%, 0.83 µg, and 27.9%, respectively, for isogenic segregants. WRI1 and WRI1-regulated genes involved in fatty acid synthesis were up-regulated, providing for a corresponding increase in the rate of fatty acid synthesis. PMID:27208047

  16. WRINKLED1 Rescues Feedback Inhibition of Fatty Acid Synthesis in Hydroxylase-Expressing Seeds.

    Science.gov (United States)

    Adhikari, Neil D; Bates, Philip D; Browse, John

    2016-05-01

    Previous attempts at engineering Arabidopsis (Arabidopsis thaliana) to produce seed oils containing hydroxy fatty acids (HFA) have resulted in low yields of HFA compared with the native castor (Ricinus communis) plant and caused undesirable effects, including reduced total oil content. Recent studies have led to an understanding of problems involved in the accumulation of HFA in oils of transgenic plants, which include metabolic bottlenecks and a decrease in the rate of fatty acid synthesis. Focusing on engineering the triacylglycerol assembly mechanisms led to modest increases in the HFA content of seed oil, but much room for improvement still remains. We hypothesized that engineering fatty acid synthesis in the plastids to increase flux would facilitate enhanced total incorporation of fatty acids, including HFA, into seed oil. The transcription factor WRINKLED1 (WRI1) positively regulates the expression of genes involved in fatty acid synthesis and controls seed oil levels. We overexpressed Arabidopsis WRI1 in seeds of a transgenic line expressing the castor fatty acid hydroxylase. The proportion of HFA in the oil, the total HFA per seed, and the total oil content of seeds increased to an average of 20.9%, 1.26 µg, and 32.2%, respectively, across five independent lines, compared with 17.6%, 0.83 µg, and 27.9%, respectively, for isogenic segregants. WRI1 and WRI1-regulated genes involved in fatty acid synthesis were up-regulated, providing for a corresponding increase in the rate of fatty acid synthesis. PMID:27208047

  17. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    Directory of Open Access Journals (Sweden)

    Xuezheng Liang

    2010-08-01

    Full Text Available The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and β-keto esters make this novel carbon based acid one of the best choices for the reaction.

  18. Synthesis, Characterisation, and Biological Evaluation of Zn(II Complex with Tridentate (NNO Donor Schiff Base Ligand

    Directory of Open Access Journals (Sweden)

    Nayaz Ahmed

    2015-01-01

    Full Text Available The present paper deals with the synthesis and characterization of metal complex of tridentate Schiff base ligand derived from the inserted condensation of 2-aminobenzimidazole (1H-benzimidazol-2-amine with salicylaldehyde (2-hydroxybenzaldehyde in a 1 : 1 molar ratio. Using this tridentate ligand, complex of Zn(II with general formula ML has been synthesized. The synthesized complex was characterized by several techniques using molar conductance, elemental analysis, FT-IR, and mass and 1HNMR spectroscopy. The elemental analysis data suggest the stoichiometry to be 1 : 1 [M : L]. The complex is nonelectrolytic in nature as suggested by molar conductance measurements. Infrared spectral data indicate the coordination between the ligand and the central metal ion through deprotonated phenolic oxygen, imidazole nitrogen of benzimidazole ring, and azomethine nitrogen atom. Spectral studies suggest tetrahedral geometry for the complex. The pure compound, synthesized ligand, and metal complex were screened for their antimicrobial activity.

  19. Suppression of glycosaminoglycan synthesis by articular cartilage, but not of hyaluronic acid synthesis by synovium, after exposure to radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hugenberg, S.T.; Myers, S.L.; Brandt, K.D.

    1989-04-01

    We recently found that injection of 2 mCi of yttrium 90 (90Y; approximately 23,000 rads) into normal canine knees stimulated glycosaminoglycan (GAG) synthesis by femoral condylar cartilage. The present investigation was conducted to determine whether radiation affects cartilage metabolism directly. Rates of GAG synthesis and degradation in normal canine articular cartilage were studied following irradiation. Cultured synovium from the same knees was treated similarly, to determine the effects of irradiation on hyaluronic acid synthesis. Twenty-four hours after exposure to 1,000 rads, 10,000 rads, or 50,000 rads, 35S-GAG synthesis by the cartilage was 93%, 69%, and 37%, respectively, of that in control, nonirradiated cartilage. The effect was not rapidly reversible: 120 hours after exposure to 50,000 rads, GAG synthesis remained at only 28% of the control level. Autoradiography showed marked suppression of 35S uptake by chondrocytes after irradiation. Cartilage GAG degradation was also increased following irradiation: 4 hours and 8 hours after exposure to 50,000 rads, the cartilage GAG concentration was only 66% and 54%, respectively, of that at time 0, while corresponding values for control, nonirradiated cartilage were 90% and 87%. In contrast to its effects on cartilage GAG metabolism, radiation at these levels had no effect on synovial hyaluronic acid synthesis.

  20. Abc Amino Acids: Design, Synthesis, and Properties of New Photoelastic Amino Acids

    Energy Technology Data Exchange (ETDEWEB)

    Standaert, Robert F [ORNL; Park, Dr Seung Bum [Seoul National University

    2006-01-01

    Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A in the backbone upon transa?cis photoisomerization. This isomer, designated mpAbc, has substituents at meta and para positions on the inner (azo-linked) and outer rings, respectively. An efficient synthesis of Fmoc-protected mpAbc was executed in which the biaryl components were formed via Suzuki couplings and the azo linkage was formed via amine/nitroso condensation; protected forms of three other Abc isomers were prepared similarly. A decapeptide incorporating mpAbc was synthesized by conventional solid-phase methods and displayed characteristic azobenzene photochemical behavior with optimal conversion to the cis isomer at 360 nm and a thermal cisa?trans half life of 100 min. at 80 AoC.

  1. Synthesis and Characterization of Fatty Acid/Amino Acid Self-Assemblies

    Directory of Open Access Journals (Sweden)

    Joanna Gajowy

    2014-10-01

    Full Text Available In this paper, we discuss the synthesis and self-assembling behavior of new copolymers derived from fatty acid/amino acid components, namely dimers of linoleic acid (DLA and tyrosine derived diphenols containing alkyl ester pendent chains, designated as “R” (DTR. Specific pendent chains were ethyl (E and hexyl (H. These poly(aliphatic/aromatic-ester-amides were further reacted with poly(ethylene glycol (PEG and poly(ethylene glycol methyl ether of different molecular masses, thus resulting in ABA type (hydrophilic-hydrophobic-hydrophilic triblock copolymers. We used Fourier transform infrared (FTIR and nuclear magnetic resonance (NMR spectroscopies to evaluate the chemical structure of the final materials. The molecular masses were estimated by gel permeation chromatography (GPC measurements. The self-organization of these new polymeric systems into micellar/nanospheric structures in aqueous environment was evaluated using ultraviolet/visible (UV-VIS spectroscopy, dynamic light scattering (DLS and transmission electron microscopy (TEM. The polymers were found to spontaneously self-assemble into nanoparticles with sizes in the range 196–239 nm and critical micelle concentration (CMC of 0.125–0.250 mg/mL. The results are quite promising and these materials are capable of self-organizing into well-defined micelles/nanospheres encapsulating bioactive molecules, e.g., vitamins or antibacterial peptides for antibacterial coatings on medical devices.

  2. Synthesis and characterization of Fatty acid/amino Acid self-assemblies.

    Science.gov (United States)

    Gajowy, Joanna; Bolikal, Durgadas; Kohn, Joachim; Fray, Miroslawa El

    2014-01-01

    In this paper, we discuss the synthesis and self-assembling behavior of new copolymers derived from fatty acid/amino acid components, namely dimers of linoleic acid (DLA) and tyrosine derived diphenols containing alkyl ester pendent chains, designated as "R" (DTR). Specific pendent chains were ethyl (E) and hexyl (H). These poly(aliphatic/aromatic-ester-amide)s were further reacted with poly(ethylene glycol) (PEG) and poly(ethylene glycol methyl ether) of different molecular masses, thus resulting in ABA type (hydrophilic-hydrophobic-hydrophilic) triblock copolymers. We used Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies to evaluate the chemical structure of the final materials. The molecular masses were estimated by gel permeation chromatography (GPC) measurements. The self-organization of these new polymeric systems into micellar/nanospheric structures in aqueous environment was evaluated using ultraviolet/visible (UV-VIS) spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). The polymers were found to spontaneously self-assemble into nanoparticles with sizes in the range 196-239 nm and critical micelle concentration (CMC) of 0.125-0.250 mg/mL. The results are quite promising and these materials are capable of self-organizing into well-defined micelles/nanospheres encapsulating bioactive molecules, e.g., vitamins or antibacterial peptides for antibacterial coatings on medical devices. PMID:25347356

  3. Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng, E-mail: zhxch@zzu.edu.cn

    2014-03-15

    MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H{sub 2}O{sub 2} indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions. Highlights: • 5–45 wt% HPW/MCM-48 mesoporous catalysts were prepared and characterized. • Their catalytic activities for the green synthesis of benzoic acid were investigated. • HPW/MCM-48 was approved to be an efficient catalyst. • 5 wt% HPW/MCM-48 exhibited the highest catalytic activity.

  4. Synthesis of Tetrahydrofuran and Tetrahydropyran Derivatives Catalyzed by Tungstophosphoric Acid in Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Synthesis of tetrahydrofuran and tetrahydropyran derivatives catalyzed by tungstophosphoric acid (H3PW12O4o) were conveniently performed with high yield from the corresponding unsaturated alcohols in ionic liquid. Sufuric acid (H2SO4), trifluoromathanesulfonic acid (TfOH)and p-toluenesulfonic acid (TsOH) were also explored for preparing these products in ionic liquid.The catalysts and ionic liquid can be easily recovered and reused.

  5. A Facile Method for Asymmetric Synthesis of β-Hydroxy-α-amino Acids

    Institute of Scientific and Technical Information of China (English)

    LI,Shuo; LI,Lei; ZHANG,Zhi-Hui; XU,Peng-Fei

    2004-01-01

    @@ β-Hydroxy-a-amino acids are an important class of amino acids due to their inherent biological investigations[1] and as structural components of more complex biomolecules.[2] β-Hydroxy-a-amino acids have been used as intermediates in the asymmetric synthesis of other compounds.[3] An efficient and convenient concise method for the preparation of optically pure enantiomers of β-hydroxy-α-amino acids would be of general interest.

  6. Synthesis, structural characterisation and antibacterial activity of Ag{sup +}-doped fluorapatite nanomaterials prepared by neutralization method

    Energy Technology Data Exchange (ETDEWEB)

    Stanić, Vojislav, E-mail: voyo@vinca.rs [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Radosavljević-Mihajlović, Ana S. [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Živković-Radovanović, Vukosava [University of Belgrade, Faculty of Chemistry, P.O. Box 51, 11158 Belgrade (Serbia); Nastasijević, Branislav; Marinović-Cincović, Milena; Marković, Jelena P.; Budimir, Milica D. [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia)

    2015-05-15

    Graphical abstract: - Highlights: • The neutralization method has been used for synthesis of silver-doped fluorapatite powders. • Particles of silver-doped fluorapatite samples are of nano size and homogenous in composition. • The Ag{sup +}-doped fluorapatite samples showed antibacterial effect against Kllebsiela pneumoniae, Staphylococcus aureus and Micrococcus luteus. • AFM studies showed that silver-doped sample causes considerable morphological changes of tested bacterial cells. - Abstract: Silver doped fluorapatite nanopowders were synthesised by neutralization method, which consists of dissolving Ag{sub 2}O in solution of HF and H{sub 3}PO{sub 4} and addition to suspension of Ca(OH){sub 2}. The powder XRD, SEM and FTIR studies indicated the formation of a fluorapatite nanomaterials with average length of the particles is about 80 nm and a width of about 15 nm. The FTIR studies show that carbonate content in samples is very small and carbonte ions substitute both phosphate and hydroxyl groups in the crystal structure of samples, forming AB-type fluorapatite. Antibacterial studies have demonstrated that all Ag{sup +}-doped fluorapatite samples exhibit bactericidal effect against pathogens: Staphylococcus aureus, Micrococcus luteus and Kllebsiela pneumoniae. Antibacterial activity increased with the increase of Ag{sup +} in the samples. The atomic force microscopy studies revealed extensive damage to the bacterial cell envelops in the presence of Ag{sup +}-doped fluorapatite particles which may lead to their death. The synthesized Ag{sup +}-doped fluorapatite nanomaterials are promising as antibacterial biomaterials in orthopedics and dentistry.

  7. Barley polyamine oxidase: Characterisation and analysis of the cofactor and the N-terminal amino acid sequence

    DEFF Research Database (Denmark)

    Radova, A.; Sebela, M.; Galuszka, P.;

    2001-01-01

    was further confirmed by measuring the fluorescence spectra, Barley PAO is an acidic protein (pI 5.4) containing 3% of neutral sugars: its molecular mass determined by SDS-PAGE was 56 kDa, whilst gel permeation chromatography revealed the higher value of 76 kDa. The N-terminal amino acid sequence of barley...

  8. Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

    Science.gov (United States)

    Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng

    2014-03-01

    MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H2O2 indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions.

  9. Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

    Science.gov (United States)

    Kato, Hiroyuki; Suzuki, Hiromi; Inoue, Yoshiko; Suzuki, Katsuya; Kobayashi, Hisamine

    2016-01-01

    Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential amino acids. We determined fractional protein synthesis rates (FSR) at different time points following exercise. Mixed protein and collagen protein FSRs in skeletal muscle were determined by measuring protein-bound enrichments of hydroxyproline and proline, and by measuring the intracellular enrichment of proline, using injections of flooding d3-proline doses. A leucine-enriched mixture of essential amino acids (or distilled water as a control) was administrated 30 min or 1 day post-exercise. The collagen protein synthesis in the vastus lateralis was elevated for 2 days after exercise. Although amino acid administration did not increase muscle collagen protein synthesis, it did lead to augmented mixed muscle protein synthesis 1 day following exercise. Thus, contrary to the regulation of mixed muscle protein synthesis, muscle collagen protein synthesis is not affected by amino acid availability after damage-inducing exercise. PMID:27367725

  10. Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

    Directory of Open Access Journals (Sweden)

    Hiroyuki Kato

    2016-06-01

    Full Text Available Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential amino acids. We determined fractional protein synthesis rates (FSR at different time points following exercise. Mixed protein and collagen protein FSRs in skeletal muscle were determined by measuring protein-bound enrichments of hydroxyproline and proline, and by measuring the intracellular enrichment of proline, using injections of flooding d3-proline doses. A leucine-enriched mixture of essential amino acids (or distilled water as a control was administrated 30 min or 1 day post-exercise. The collagen protein synthesis in the vastus lateralis was elevated for 2 days after exercise. Although amino acid administration did not increase muscle collagen protein synthesis, it did lead to augmented mixed muscle protein synthesis 1 day following exercise. Thus, contrary to the regulation of mixed muscle protein synthesis, muscle collagen protein synthesis is not affected by amino acid availability after damage-inducing exercise.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  12. A thermodynamic basis for prebiotic amino acid synthesis and the nature of the first genetic code

    CERN Document Server

    Higgs, Paul G

    2009-01-01

    Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these ten early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.

  13. Synthesis and characterisation of Stannate ceramics for application as high performance material; Synthese und Charakterisierung von Stannat-Keramiken fuer die Verwendung als Hochleistungswerkstoff

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, A.

    2003-07-01

    New optimised wet-chemical routes (precipitation, polymerisation and sol-gel) for the production of pure, homogenic and nanocrystalline perovskitic earth alkali stannate powders (Ba- and SrSnO{sub 3}) were investigated. One of the routes was used to synthesise substituted partly new stannate ceramics (Ba{sub 2}YSnO{sub 5.5}, Ba{sub 2}NdSnO{sub 5.5} and nonstoichiometric compositions). The characterisation includes thermal analysis, Fourier transform infrared spectroscopy, x-ray diffraction and quantitative phase analysis. Further, results of impedance spectroscopy on the substituted powders are discussed. Thermal analysis data provide information about the precursor i. e. phase transition, ordering onset and mass changes. FTIR spectroscopy is both used to identify functional groups in the precursor and to compare with starting reagents as well as to investigate the surface behaviour of the calcined powders, i. e. adsorption of CO{sub 2} or water. X-ray diffraction data are used to compare the products in terms of phase purity and identification of additional phases as well as determination of crystallite size and distribution, structural parameters and quantitative phase analysis (target product and additional phases). The synthesis routes are compared and evaluated. The polymerisation and sol-gel-routes provide the best products in terms of material specific parameters. Different impedance spectra of Ba{sub 2}YSnO{sub 5.5}, Ba{sub 2}NdSnO{sub 5.5} and ''nonstoichiometric'' ceramics measured between RT and ca. 600 C are presented and calculated values for the specific conductance are shown. Ba{sub 2}YSnO{sub 5.5} can be applied as good conductive compound, Ba{sub 2}NdSnO{sub 5.5} and nonstoichiometric compositions as possible candidates for a membrane in a SOFC or as sensor material. (orig.)

  14. Synthesis and spectroscopic studies of iron (III) complex with a quinolone family member (pipemidic acid)

    Science.gov (United States)

    Skrzypek, D.; Szymanska, B.; Kovala-Demertzi, Dimitra; Wiecek, Joanna; Talik, E.; Demertzis, Mavroudis A.

    2006-12-01

    The interaction of iron (III) with pipemidic acid, Hpipem, afforded the complex [Fe (pipem) (HO)2 (H2O)]2. The new complex has been characterised by elemental analyses, infra-red, EPR and XPS spectroscopies. The monoanion, pipem, exhibits O, O ligation through the carbonyl and carboxylato oxygen atoms. Six coordinate dimer distorted octahedral configuration has been proposed for [Fe (pipem) (HO)2 (H2O)]2.

  15. The Prebiotic Synthesis of Ethylenediamine Monoacetic Acid, The Repeating Unit of Peptide Nucleic Acids

    Science.gov (United States)

    Nelson, Kevin E.; Miller, Stanley L.

    1992-01-01

    The polymerization of ribonucleic acids or their precursors constitutes an important event in prebiotic chemistry. The various problems using ribonucleotides to make RNA suggest that there may have been a precursor. An attractive possibility are the peptide nucleic acids (PNA). PNAs are nucleotide analogs that make use of a polymer of ethylenediamine monoacetic acid (EDMA or 2-amninoethyl glycine) with the bases attached by an acetic acid. EDMA is an especially attractive alternative to the ribose phosphate or deoxyribose phosphate backbone because it contains no chiral centers and is potentially prebiotic, but there is no reported prebiotic synthesis. We have synthesized both EDMA and ethylenediamine diacetic acid (EDDA) from the prebiotic compounds ethylenediamine, formaldehyde, and hydrogen cyanide. The yields of EDMA range from 11 to 79% along with some sEDDA and uEDDA. These reactions work with concentrations of 10(exp -1)M and as low as 10(exp -4)M, and the reaction is likely to be effective at even lower concentrations. Ethylenediamine is a likely prebiotic compound, but it has not yet been demonstrated, although compounds such as ethanolamine and cysteamine have been proven to be prebiotic. Under neutral pH and heating at l00 C, EDMA is converted to the lactam, monoketopiperazine (MKP). The cyclization occurs and has an approximate ratio of MKP/EDMA = 3 at equilibrium. We have measured the solubilities of EDMA center dot H20 as 6.4 m, EDMA center dot HCl center dot H20 as 13.7 m, and EDMA center dot 2HCl center dot H20 as 3.4 m. These syntheses together with the high solubility of EDMA suggest that EDMA would concentrate in drying lagoons and might efficiently form polymers. Given the instability of ribose and the poor polymerizability of nucleotides, the prebiotic presence of EDMA and the possibility of its polymerization raises the possibility that PNAs are the progenitors of present day nucleic acids. A pre-RNA world may have existed in which PNAs or

  16. Fish oil increases bile acid synthesis in male patients with hypertriglyceridemia

    NARCIS (Netherlands)

    Jonkers, IJAM; Smelt, AHM; Princen, HMG; Kuipers, F; Romijn, JA; Boverhof, R; Masclee, AAM; Stellaard, F

    2006-01-01

    Fibrates are drugs of choice in patients with hypertriglyceridemia (HTG), but may increase the risk for gallstones by decreasing bile acid synthesis. Fish oil might be a therapeutic alternative, but its effect on bile acid metabolism in humans is unknown. We compared the effects of triglyceride-lowe

  17. Design and Synthesis of Chiral Molecular Tweezers Based on Deoxycholic Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms.Instead of using toxic phosgene,the triphosgene was employed in synthesis of the molecular tweezers receptors.These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.

  18. Synthesis of Long Chain Unsaturated-alpha,omega-Dicarboxylic Acids from Renewable Materials via Olefin Metathesis

    Science.gov (United States)

    The self-metathesis reaction of soy, rapeseed, tall, and linseed oil fatty acids was investigated for the synthesis of symmetrical long-chain unsaturated-alpha,omega-dicarboxylic acids. The metathesis reactions were carried out in the presence of a Grubbs catalyst under solvent-free conditions at a...

  19. Microwave-assisted base-free synthesis of trans-cinnamic acids using hypervalent iodonium salts

    Institute of Scientific and Technical Information of China (English)

    Min Zhu; Chao Shentu; Zhong Shi Zhou

    2007-01-01

    A fast and convenient base-free Heck reaction of acrylic acid with hypervalent iodonium salts was achieved under microwave irradiation in water, providing a simple method for the synthesis of trans-cinnamic acids in good yields in short time.

  20. Synthesis of 6-phosphofructose aspartic acid and some related Amadori compounds.

    Science.gov (United States)

    Hansen, Alexandar L; Behrman, Edward J

    2016-08-01

    We describe the synthesis and characterization of 6-phosphofructose-aspartic acid, an intermediate in the metabolism of fructose-asparagine by Salmonella. We also report improved syntheses of fructose-asparagine itself and of fructose-aspartic acid. PMID:27258673

  1. Synthesis of β3-Amino Acids via Catalyst- and Solvent-Free Aza-Michael Reaction

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A safe, environmentally friendly and cost-effective method for the synthesis of β-amino acid derivatives has been developed. Treatment of α,β-unsaturated compounds with aliphatic amines furnishes β-amino acid derivatives in good to excellent yields via a catalyst- and solvent-free aza-Michael addition.

  2. Synthesis of novel trivalent amino acid glycoconjugates based on the cyclotriveratrylene ('CTV') scaffold.

    Science.gov (United States)

    van Ameijde, Jeroen; Liskamp, Rob M J

    2003-08-01

    The convenient synthesis of novel trivalent amino acid glycoconjugates based on cyclotriveratrylene ('CTV') is described. These constructs consist of the CTV scaffold, three oligoethylene glycol spacers of variable length connected to a glyco amino acid residue which can also be varied. The resulting library of trivalent glycoconjugates can be used for studying multivalent interactions. PMID:12948190

  3. Potency of individual bile acids to regulate bile acid synthesis and transport genes in primary human hepatocyte cultures.

    Science.gov (United States)

    Liu, Jie; Lu, Hong; Lu, Yuan-Fu; Lei, Xiaohong; Cui, Julia Yue; Ellis, Ewa; Strom, Stephen C; Klaassen, Curtis D

    2014-10-01

    Bile acids (BAs) are known to regulate their own homeostasis, but the potency of individual bile acids is not known. This study examined the effects of cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA) on expression of BA synthesis and transport genes in human primary hepatocyte cultures. Hepatocytes were treated with the individual BAs at 10, 30, and 100μM for 48 h, and RNA was extracted for real-time PCR analysis. For the classic pathway of BA synthesis, BAs except for UDCA markedly suppressed CYP7A1 (70-95%), the rate-limiting enzyme of bile acid synthesis, but only moderately (35%) down-regulated CYP8B1 at a high concentration of 100μM. BAs had minimal effects on mRNA of two enzymes of the alternative pathway of BA synthesis, namely CYP27A1 and CYP7B1. BAs increased the two major target genes of the farnesoid X receptor (FXR), namely the small heterodimer partner (SHP) by fourfold, and markedly induced fibroblast growth factor 19 (FGF19) over 100-fold. The BA uptake transporter Na(+)-taurocholate co-transporting polypeptide was unaffected, whereas the efflux transporter bile salt export pump was increased 15-fold and OSTα/β were increased 10-100-fold by BAs. The expression of the organic anion transporting polypeptide 1B3 (OATP1B3; sixfold), ATP-binding cassette (ABC) transporter G5 (ABCG5; sixfold), multidrug associated protein-2 (MRP2; twofold), and MRP3 (threefold) were also increased, albeit to lesser degrees. In general, CDCA was the most potent and effective BA in regulating these genes important for BA homeostasis, whereas DCA and CA were intermediate, LCA the least, and UDCA ineffective.

  4. Improved One-pot Synthesis of 4,6-Dihydroxyisophthalic Acid and 2,3-Dihydroxyterephthalic Acid

    Institute of Scientific and Technical Information of China (English)

    Guang Dong LEI; Li Xin LI; Zhi Yun LU; Ming Gui XIE

    2005-01-01

    An improved method for the large-scale preparation of 4,6-dihydroxyisophthalic acid and 2,3-dihydroxyterephthalic acid has been developed. Compared to the previous procedures,this new process requires much lower CO2 pressure of 0.3 Mpa and shorter reaction time, thus providing a convenient access for large-scale synthesis. The yield is high (93% and 65%,respectively), and the oxidation of phenol is nearly inhibited, neither decolorization nor further chromatographic purification is required.

  5. Synthesis of deuterium-labelled methylphenidate, p-hydroxy-methylphenidate, ritalinic acid and p-hydroxyritalinic acid

    International Nuclear Information System (INIS)

    The synthesis of threo-dl-methylphenidate (Ritalin 1), threo-dl-p-hydroxy-methylphenidate (3), threo-dl-ritalinic acid (2), and threo-dl-p-hydroxyritalinic acid (4) with deuterium incorporated in the piperidine ring is described. These compounds were synthesized for use as internal standards for mass fragmentographic assays of methylphenidate and its metabolites. The synthetic scheme described resulted in less than 0.05% 2H0 in the piperidine ring in any of the preparations. (author)

  6. Synthesis of deuterium-labelled methylphenidate, p-hydroxy-methylphenidate, ritalinic acid and p-hydroxyritalinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, K.; Kilts, C.; Breese, G. (North Carolina Univ., Chapel Hill (USA). School of Medicine)

    1982-04-01

    The synthesis of threo-dl-methylphenidate (Ritalin 1), threo-dl-p-hydroxy-methylphenidate (3), threo-dl-ritalinic acid (2), and threo-dl-p-hydroxyritalinic acid (4) with deuterium incorporated in the piperidine ring is described. These compounds were synthesized for use as internal standards for mass fragmentographic assays of methylphenidate and its metabolites. The synthetic scheme described resulted in less than 0.05% /sup 2/H/sub 0/ in the piperidine ring in any of the preparations.

  7. Synthesis, Characterisation, and Evaluation of a Cross-Linked Disulphide Amide-Anhydride-Containing Polymer Based on Cysteine for Colonic Drug Delivery

    Directory of Open Access Journals (Sweden)

    Vuanghao Lim

    2013-12-01

    Full Text Available The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide-3-mercapto propionic anhydride (trithiol monomers using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5–1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.

  8. Synthesis, characterisation, and evaluation of a cross-linked disulphide amide-anhydride-containing polymer based on cysteine for colonic drug delivery.

    Science.gov (United States)

    Lim, Vuanghao; Peh, Kok Khiang; Sahudin, Shariza

    2013-12-18

    The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide)-3-mercapto propionic anhydride (trithiol monomers) using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5-1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.

  9. [New synthesis of the anticoagulant pentasaccharide idraparinux and preparation of its analogues containing sulfonic acid moieties].

    Science.gov (United States)

    Herczeg, Mihály

    2012-01-01

    Two novel synthetic pathways were elaborated for the preparation of idraparinux, a heparin-related fully O-sulfated, O-methylated anticoagulant pentasaccharide. Both methods based upon a [2+3] block synthesis utilizing the same trisaccharide acceptor which was coupled to either a uronic acid disaccharide donor or its nonoxidized precursor. Two bioisosteric sulfonic acid analogues of idraparinux were also prepared, in which two or three primary sulfate esters were replaced by sodium-sulfonatomethyl moieties. The sulfonic acid groups were formed on a monosaccharide level and the obtained carbohydrate sulfonic acid esters were found to be excellent donors and acceptors in the glycosylation reactions. The disulfonic-acid analogue was prepared in a [2+3] block synthesis by using a trisaccharide disulfonic acid as an acceptor and a glucuronide disaccharide as a donor. For the synthesis of the pentasaccharide trisulfonic acid, a more-efficient approach, which involved elongation of the trisaccharide acceptor with a non-oxidized precursor of the glucuronic acid followed by post-glycosidation oxidation at the tetrasaccharide level and a subsequent [1+4] coupling reaction, was elaborated. In vitro evaluation of the anticoagulant activity of the reference compound idraparinux and the new sulfonic acid derivatives revealed that the disulfonate analogue inhibited the blood-coagulation-proteinase factor Xa with outstanding efficacy; however, the introduction of the third sulfonic acid moiety resulted in a notable decrease in the anti-Xa activity. PMID:23230650

  10. Chemical Synthesis of Uncommon Natural Bile Acids: The 9α-Hydroxy Derivatives of Chenodeoxycholic and Lithocholic Acids.

    Science.gov (United States)

    Iida, Takashi; Namegawa, Kazunari; Nakane, Naoya; Iida, Kyoko; Hofmann, Alan Frederick; Omura, Kaoru

    2016-09-01

    The chemical synthesis of the 9α-hydroxy derivatives of chenodeoxycholic and lithocholic acids is reported. For initiating the synthesis of the 9α-hydroxy derivative of chenodeoxycholic acid, cholic acid was used; for the synthesis of the 9α-hydroxy derivative of lithocholic acid, deoxycholic acid was used. The principal reactions involved were (1) decarbonylation of conjugated 12-oxo-Δ(9(11))-derivatives using in situ generated monochloroalane (AlH2Cl) prepared from LiAlH4 and AlCl3, (2) epoxidation of the deoxygenated Δ(9(11))-enes using m-chloroperbenzoic acid catalyzed by 4,4'-thiobis-(6-tert-butyl-3-methylphenol), (3) subsequent Markovnikov 9α-hydroxylation of the Δ(9(11))-enes with AlH2Cl, and (4) selective oxidation of the primary hydroxyl group at C-24 in the resulting 3α,9α,24-triol and 3α,7α,9α,24-tetrol to the corresponding C-24 carboxylic acids using sodium chlorite (NaClO2) in the presence of a catalytic amount of 2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO) and sodium hypochlorite (NaOCl). The (1)H- and (13)C-NMR spectra are reported. The 3α,7α,9α-trihydroxy-5β-cholan-24-oic acid has been reported to be present in the bile of the Asian bear, and its 7-deoxy derivative is likely to be a bacterial metabolite. These bile acids are now available as authentic reference standards, permitting their identification in vertebrate bile acids. PMID:27319285

  11. Decreased hepatotoxic bile acid composition and altered synthesis in progressive human nonalcoholic fatty liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Lake, April D. [University of Arizona, Department of Pharmacology and Toxicology, Tucson, AZ 85721 (United States); Novak, Petr [Biology Centre ASCR, Institute of Plant Molecular Biology, Ceske Budejovice 37001 (Czech Republic); Shipkova, Petia; Aranibar, Nelly; Robertson, Donald; Reily, Michael D. [Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Co., Princeton, NJ 08543 (United States); Lu, Zhenqiang [The Arizona Statistical Consulting Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Lehman-McKeeman, Lois D. [Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Co., Princeton, NJ 08543 (United States); Cherrington, Nathan J., E-mail: cherrington@pharmacy.arizona.edu [University of Arizona, Department of Pharmacology and Toxicology, Tucson, AZ 85721 (United States)

    2013-04-15

    Bile acids (BAs) have many physiological roles and exhibit both toxic and protective influences within the liver. Alterations in the BA profile may be the result of disease induced liver injury. Nonalcoholic fatty liver disease (NAFLD) is a prevalent form of chronic liver disease characterized by the pathophysiological progression from simple steatosis to nonalcoholic steatohepatitis (NASH). The hypothesis of this study is that the ‘classical’ (neutral) and ‘alternative’ (acidic) BA synthesis pathways are altered together with hepatic BA composition during progression of human NAFLD. This study employed the use of transcriptomic and metabolomic assays to study the hepatic toxicologic BA profile in progressive human NAFLD. Individual human liver samples diagnosed as normal, steatosis, and NASH were utilized in the assays. The transcriptomic analysis of 70 BA genes revealed an enrichment of downregulated BA metabolism and transcription factor/receptor genes in livers diagnosed as NASH. Increased mRNA expression of BAAT and CYP7B1 was observed in contrast to decreased CYP8B1 expression in NASH samples. The BA metabolomic profile of NASH livers exhibited an increase in taurine together with elevated levels of conjugated BA species, taurocholic acid (TCA) and taurodeoxycholic acid (TDCA). Conversely, cholic acid (CA) and glycodeoxycholic acid (GDCA) were decreased in NASH liver. These findings reveal a potential shift toward the alternative pathway of BA synthesis during NASH, mediated by increased mRNA and protein expression of CYP7B1. Overall, the transcriptomic changes of BA synthesis pathway enzymes together with altered hepatic BA composition signify an attempt by the liver to reduce hepatotoxicity during disease progression to NASH. - Highlights: ► Altered hepatic bile acid composition is observed in progressive NAFLD. ► Bile acid synthesis enzymes are transcriptionally altered in NASH livers. ► Increased levels of taurine and conjugated bile acids

  12. A review on synthesis and characterization of solid acid materials for fuel cell applications

    Science.gov (United States)

    Mohammad, Norsyahida; Mohamad, Abu Bakar; Kadhum, Abdul Amir H.; Loh, Kee Shyuan

    2016-08-01

    Solid acids emerged as an electrolyte material for application in fuel cells due to their high protonic conductivity and stability at high temperatures between 100 °C and 250 °C. This paper gives an overview of the different solid acid materials and their properties, such as high protonic conductivity and thermal stability, in relation to phase transitions and mechanisms of proton transport. Various solid acid synthesis methods including aqueous and dry mixing, electrospinning, sol-gel, impregnation and thin-film casting will be discussed, and the impact of synthesis methods on the properties of solid acids will be highlighted. The properties of solid acids synthesized as either single crystals and or polycrystalline powders were identified via X-ray diffraction, nuclear magnetic resonance, thermal analyses, optical microscopy and infrared spectroscopy. A selection of electrolyte-electrode assembly methods and the performance of solid acid fuel cell prototypes are also reviewed.

  13. X-Ray Characterisation of Various Aluminium Phases in the Medicinal Herb Bacopa Monnieri Affected by Simulated Acid Rain

    OpenAIRE

    Mallick, B.

    2012-01-01

    In the present investigation various aluminium-based new phases formed due to substitution of sulphur via simulated acid rain in Bacopa monnieri have been analyzed using X-ray diffraction (XRD) technique. So far there is no report on the effects of acid rain on the B. monnieri herb and its vital properties like memory-boosting mechanism. Therefore, in the present study, an attempt has been made to analyze the various aluminium phase (salt) formations due to the substitution of sulphur via sim...

  14. Characterisation of fatty acid, carotenoid, tocopherol/tocotrienol compositions and antioxidant activities in seeds of three Chenopodium quinoa Willd. genotypes.

    Science.gov (United States)

    Tang, Yao; Li, Xihong; Chen, Peter X; Zhang, Bing; Hernandez, Marta; Zhang, Hua; Marcone, Massimo F; Liu, Ronghua; Tsao, Rong

    2015-05-01

    Composition of fatty acids, tocopherols, tocotrienols, and carotenoids, and their contribution to antioxidant activities were investigated in seeds of three coloured quinoa cultivars (white, red and black). The major components and individual compounds were significantly different, and their concentrations were higher in darker seeds (p quinoa had the highest vitamin E followed by red and white quinoas. Carotenoids, mainly trans-lutein (84.7-85.6%) and zeaxanthin were confirmed for the first time in quinoa seeds, and the concentration was also the highest in black seeds. The antioxidant activities of lipophilic extracts were positively correlated with polyunsaturated fatty acids, total carotenoids and total tocopherols. PMID:25529712

  15. Synthesis and characterization of humic acids with distinct redox capacities

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, S.; Heise, K.H.; Bernhard, G.

    2002-05-01

    Various humic acids with distinct redox capacities were synthesized, based on the oxidation of hydroquinone in alkaline solution in the presence or absence of amino acids. The synthesized humic acids show Fe(III) redox capacities which are up to 10 times higher than that of natural humic acid from Aldrich. (orig.)

  16. Synthesis and Characterization of Dual Acidic Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Xiao Hua WANG; Guo Hong TAO; Zi Yan ZHANG; Yuan KOU

    2005-01-01

    Novel ionic liquids with dual acidity, of which the cation contains Bronsted acidity and anions contain Lewis acidity were synthesized. These ionic liquids obtained were identified by NMR,FT-IR, SDT and FAB-MS. Their acidities were determined by pyridine probe on IR spectrography.

  17. Green Synthesis and Urease Inhibitory Activity of Spiro-Pyrimidinethiones/Spiro-Pyrimidinones-Barbituric Acid Derivatives

    OpenAIRE

    Mohammadi Ziarani, Ghodsi; Asadi, Shima; Faramarzi, Sakineh; Amanlou, Massoud

    2015-01-01

    Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) with pore size 6 nm as an efficient heterogeneous nanoporous solid acid catalyst exhibited good catalytic activity in the Biginelli-like reaction in the synthesis of spiroheterobicyclic rings with good yield and good recyclability. Spiro-pyrimidinethiones/spiro-pyrimidinones-barbituric acid derivatives were synthesized in a simple and efficient method using the one-pot three-component reaction of a cyclic 1,3- dicarbonyl compounds (barbituric ...

  18. Synthesis of novel (1-alkanoyloxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives

    OpenAIRE

    Vepsäläinen Jouko J; Turhanen Petri A

    2006-01-01

    Abstract A novel strategy for the synthesis of (1-alkanoyloxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives (1a-d) via (1-hydroxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives (2a-d), starting from alendronate has been developed with reasonable 51–77% overall yields. Intermediate products, (1-hydroxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives (2a-d), were prepared in water with reasonable to high yields (52–94%).

  19. X-Ray Characterisation of Various Aluminium Phases in the Medicinal Herb Bacopa Monnieri Affected by Simulated Acid Rain

    Directory of Open Access Journals (Sweden)

    B. Mallick

    2012-07-01

    Full Text Available In the present investigation various aluminium-based new phases formed due to substitution of sulphur via simulated acid rain in Bacopa monnieri have been analyzed using X-ray diffraction (XRD technique. So far there is no report on the effects of acid rain on the B. monnieri herb and its vital properties like memory-boosting mechanism. Therefore, in the present study, an attempt has been made to analyze the various aluminium phase (salt formations due to the substitution of sulphur via simulated acid rain (SiAR in B. Monnieri because of its toxicological importance. The new phases like AlH(SO42 and Al2S3 along with usual Al2O3:H2O, MgO, FeAl2(PO42(OH2:8H2O, (K2Ca(SO42:H2O, have been observed in B. monnieri when treated with sulphuric-simulated acid rain (S-SiAR of two different pH (3.39 and 5.45 for 20 weeks. These Al-based new salts formed in the above medicinal herb due to the induction of S-SiAR may cause Alzheimer’s disease and induce other abnormities.

  20. Characterisation of SalRAB a salicylic acid inducible positively regulated efflux system of Rhizobium leguminosarum bv viciae 3841.

    Science.gov (United States)

    Tett, Adrian J; Karunakaran, Ramakrishnan; Poole, Philip S

    2014-01-01

    Salicylic acid is an important signalling molecule in plant-microbe defence and symbiosis. We analysed the transcriptional responses of the nitrogen fixing plant symbiont, Rhizobium leguminosarum bv viciae 3841 to salicylic acid. Two MFS-type multicomponent efflux systems were induced in response to salicylic acid, rmrAB and the hitherto undescribed system salRAB. Based on sequence similarity salA and salB encode a membrane fusion and inner membrane protein respectively. salAB are positively regulated by the LysR regulator SalR. Disruption of salA significantly increased the sensitivity of the mutant to salicylic acid, while disruption of rmrA did not. A salA/rmrA double mutation did not have increased sensitivity relative to the salA mutant. Pea plants nodulated by salA or rmrA strains did not have altered nodule number or nitrogen fixation rates, consistent with weak expression of salA in the rhizosphere and in nodule bacteria. However, BLAST analysis revealed seventeen putative efflux systems in Rlv3841 and several of these were highly differentially expressed during rhizosphere colonisation, host infection and bacteroid differentiation. This suggests they have an integral role in symbiosis with host plants.

  1. Characterisation of SalRAB a salicylic acid inducible positively regulated efflux system of Rhizobium leguminosarum bv viciae 3841.

    Directory of Open Access Journals (Sweden)

    Adrian J Tett

    Full Text Available Salicylic acid is an important signalling molecule in plant-microbe defence and symbiosis. We analysed the transcriptional responses of the nitrogen fixing plant symbiont, Rhizobium leguminosarum bv viciae 3841 to salicylic acid. Two MFS-type multicomponent efflux systems were induced in response to salicylic acid, rmrAB and the hitherto undescribed system salRAB. Based on sequence similarity salA and salB encode a membrane fusion and inner membrane protein respectively. salAB are positively regulated by the LysR regulator SalR. Disruption of salA significantly increased the sensitivity of the mutant to salicylic acid, while disruption of rmrA did not. A salA/rmrA double mutation did not have increased sensitivity relative to the salA mutant. Pea plants nodulated by salA or rmrA strains did not have altered nodule number or nitrogen fixation rates, consistent with weak expression of salA in the rhizosphere and in nodule bacteria. However, BLAST analysis revealed seventeen putative efflux systems in Rlv3841 and several of these were highly differentially expressed during rhizosphere colonisation, host infection and bacteroid differentiation. This suggests they have an integral role in symbiosis with host plants.

  2. Synthesis and structural analysis of 13C-fatty acids

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The 13C-labeled fatty acids octanoic-1-13C acid and palmitic-l-13C acid were synthetically prepared from Ba 13CO3. The yield of the former was more than 90% and that of the latter was above 85%. MS, IR, 1H-NMR and 13NMR were performed to analyze the structures of the two 13C-fatty acids, compared with their unlabeled fatty acids.

  3. A biochemical model for characterising the surface-active phospolipid bilayer of articular cartilage relative to acid-base equilibrium

    Directory of Open Access Journals (Sweden)

    Z. Pawlak

    2008-01-01

    Full Text Available Purpose: This paper, addresses the question of how changes in acid - base equilibrium influence change in thecharge density of the phospholipid bilayer on articular cartilage surfaces during lubrication.Design/methodology/approach: Liposomes have been used to mimic biological phospholipid membranes onarticular cartilage surface where proteins are bounded, ions are transported, energy is transducted, and cellular processestake place. The charge density of the membrane was determined as a function of pH and electrolyte concentration fromthe microelectrophoretic method. Liposome membrane was prepared as an aqueous solution of NaCl under variouspH conditions. Microelectrophoresis was used to examine the local acid-base equilibrium of the electrolytes with themembrane surface, which can be considered to model the phospholipids interface in articular cartilage.Findings: The adsorbed ions (H+, OH-, Na+, Cl- which are present in the electrically charged solutions of liposomemembrane comprising phosphatidycholine (PC, were found to exhibit pH-responsive quasi-periodic behavior.Research limitations/implications: We have established that the acid-base dissociation behavior inphospholipid bilayers of articular cartilage is a key to understanding biolubrication processes. For example,previous investigators found that the formation of the multilayer of polyisopeptide/hyaluronic acid depends onsurface properties such as film thickness, surface friction, surface wetability; wetness and swelling behavior.Future work should consider the adsorption of polyelectrolyte ions, e.g., the glycoprotein lubricin and hyaluronan,on the liposome membrane surface in the presence of H+ and OH- ions.Originality/value: A novel model of the joints’ phospholipid bilayers has been created using liposome membraneThis model can be applied in the investigation of polyelectrolyte ions such as lubricin, in articular cartilage. Wehave demonstrated that the acid-base processes on

  4. Direct microwave-assisted amino acid synthesis by reaction of succinic acid and ammonia in the presence of magnetite

    Science.gov (United States)

    Jiang, Nan; Liu, Dandan; Shi, Weiguang; Hua, Yingjie; Wang, Chongtai; Liu, Xiaoyang

    2013-10-01

    Since the discovery of submarine hot vents in the late 1970s, it has been postulated that submarine hydrothermal environments would be suitable for emergence of life on Earth. To simulate warm spring conditions, we designed a series of microwave-assisted amino acid synthesis involving direct reactions between succinic acid and ammonia in the presence of the magnetite catalyst. These reactions which generated aspartic acid and glycine were carried out under mild temperatures and pressures (90-180 °C, 4-19 bar). We studied this specific reaction inasmuch as succinic acid and ammonia were traditionally identified as prebiotic compounds in primitive deep-sea hydrothermal systems on Earth. The experimental results were discussed in both biochemical and geochemical context to offer a possible route for abiotic amino acid synthesis. With extremely diluted starting materials (0.002 M carboxylic acid and 0.002 M ammonia) and catalyst loading, an obvious temperature dependency was observed in both cases [neither product was detected at 90 °C in comparison with 21.08 μmol L-1 (aspartic acid) and 70.25 umol L-1 (glycine) in 180 °C]. However, an opposite trend presented for reaction time factor, namely a positive correlation for glycine, but a negative one for aspartic acid.

  5. Visible-light photoredox synthesis of unnatural chiral α-amino acids.

    Science.gov (United States)

    Jiang, Min; Jin, Yunhe; Yang, Haijun; Fu, Hua

    2016-01-01

    Unnatural chiral α-amino acids are widely used in fields of organic chemistry, biochemistry and medicinal chemistry, and their synthesis has attracted extensive attention. Although the asymmetric synthesis provides some efficient protocols, noble and elaborate catalysts, ligands and additives are usually required which leads to high cost. Distinctly, it is attractive to make unnatural chiral α-amino acids from readily available natural α-amino acids through keeping of the existing chiral α-carbon. However, it is a great challenge to construct them under mild conditions. In this paper, 83 unnatural chiral α-amino acids were prepared at room temperature under visible-light assistance. The protocol uses two readily available genetically coded proteinogenic amino acids, L-aspartic acid and glutamic acid derivatives as the chiral sources and radical precursors, olefins, alkynyl and alkenyl sulfones, and 2-isocyanobiphenyl as the radical acceptors, and various unnatural chiral α-amino acids were prepared in good to excellent yields. The simple protocol, mild conditions, fast reactions, and high efficiency make the method an important strategy for synthesis of diverse unnatural chiral α-amino acids. PMID:27185220

  6. A biochemical model for characterising the surface-active phospolipid bilayer of articular cartilage relative to acid-base equilibrium

    OpenAIRE

    Z. Pawlak; J. Kotynska; Figaszewski, Z A; A. Gadomski; A. Gudaniec; A. Oloyede

    2008-01-01

    Purpose: This paper, addresses the question of how changes in acid - base equilibrium influence change in thecharge density of the phospholipid bilayer on articular cartilage surfaces during lubrication.Design/methodology/approach: Liposomes have been used to mimic biological phospholipid membranes onarticular cartilage surface where proteins are bounded, ions are transported, energy is transducted, and cellular processestake place. The charge density of the membrane was determined as a funct...

  7. Isolation and characterisation of antifungal compounds from lactic acid bacteria and their application in wheat and gluten-free bread

    OpenAIRE

    Axel, Claudia

    2015-01-01

    As part of the “free-from” trend, biopreservation for bread products has increasingly become important to prevent spoilage since artificial preservatives are more and more rejected by consumers. A literature review conducted as part of this thesis revealed that the evaluation of more suitable antifungal strains of lactic acid bacteria (LAB) is important. Moreover, increasing the knowledge about the origin of the antifungal effect is fundamental for further enhancement of biopreservation. This...

  8. Tethered Aminohydroxylation: Synthesis of the β-Amino Acid of Microsclerodermins A and B

    OpenAIRE

    Pullin, Robert D. C.; Rathi, Akshat H.; Melikhova, Ekaterina Y.; Winter, Christian; Thompson, Amber L.; Donohoe, Timothy J.

    2013-01-01

    The utility of the tethered aminohydroxylation (TA) has been demonstrated by synthesis of the complex β-amino acid residue of microsclerodermins A and B. The TA provided a regio- and stereoselective functionalization of a complex homoallylic alcohol. The route includes late-stage introduction of the aliphatic side chain via a cuprate addition and cross metathesis, a tactic designed to render the synthesis applicable to other microsclerodermins.

  9. Synthesis of novel fullerene α-amino acid conjugates

    Institute of Scientific and Technical Information of China (English)

    Jing Zhang; Yan Xia Wang; Feng Kang; Ying Ya Shao; Zong Jie Li; Xin Lin Yang

    2008-01-01

    Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas)and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.

  10. Kinetic Characterisation of a Single Chain Antibody against the Hormone Abscisic Acid: Comparison with Its Parental Monoclonal

    Science.gov (United States)

    Badescu, George O.; Marsh, Andrew; Smith, Timothy R.; Thompson, Andrew J.; Napier, Richard M.

    2016-01-01

    A single-chain Fv fragment antibody (scFv) specific for the plant hormone abscisic acid (ABA) has been expressed in the bacterium Escherichia coli as a fusion protein. The kinetics of ABA binding have been measured using surface plasmon resonance spectrometry (BIAcore 2000) using surface and solution assays. Care was taken to calculate the concentration of active protein in each sample using initial rate measurements under conditions of partial mass transport limitation. The fusion product, parental monoclonal antibody and the free scFv all have low nanomolar affinity constants, but there is a lower dissociation rate constant for the parental monoclonal resulting in a three-fold greater affinity. Analogue specificity was tested and structure-activity binding preferences measured. The biologically-active (+)-ABA enantiomer is recognised with an affinity three orders of magnitude higher than the inactive (-)-ABA. Metabolites of ABA including phaseic acid, dihydrophaseic acid and deoxy-ABA have affinities over 100-fold lower than that for (+)-ABA. These properties of the scFv make it suitable as a sensor domain in bioreporters specific for the naturally occurring form of ABA. PMID:27023768

  11. Kinetic Characterisation of a Single Chain Antibody against the Hormone Abscisic Acid: Comparison with Its Parental Monoclonal.

    Directory of Open Access Journals (Sweden)

    George O Badescu

    Full Text Available A single-chain Fv fragment antibody (scFv specific for the plant hormone abscisic acid (ABA has been expressed in the bacterium Escherichia coli as a fusion protein. The kinetics of ABA binding have been measured using surface plasmon resonance spectrometry (BIAcore 2000 using surface and solution assays. Care was taken to calculate the concentration of active protein in each sample using initial rate measurements under conditions of partial mass transport limitation. The fusion product, parental monoclonal antibody and the free scFv all have low nanomolar affinity constants, but there is a lower dissociation rate constant for the parental monoclonal resulting in a three-fold greater affinity. Analogue specificity was tested and structure-activity binding preferences measured. The biologically-active (+-ABA enantiomer is recognised with an affinity three orders of magnitude higher than the inactive (--ABA. Metabolites of ABA including phaseic acid, dihydrophaseic acid and deoxy-ABA have affinities over 100-fold lower than that for (+-ABA. These properties of the scFv make it suitable as a sensor domain in bioreporters specific for the naturally occurring form of ABA.

  12. Synthesis and role of salicylic acid in wheat varieties with different levels of cadmium tolerance

    International Nuclear Information System (INIS)

    Highlights: • Cd induces the salicylic acid metabolism in wheat. • Salicylic acid is synthesized via benzoic acid and/or ortho-hydroxy-cinnamic acid. • Cd tolerance can be explained by the highly induced glutathione metabolism. • Salicylic acid signalling is correlated with glutathione-related mechanisms. - Abstract: Wheat genotypes with different endogenous SA contents were investigated, in order to reveal how cadmium influences salicylic acid (SA) synthesis, and to find possible relationships between SA and certain protective compounds (members of the antioxidants and the heavy metal detoxification system) and between the SA content and the level of cadmium tolerance. Cadmium exposure induced SA synthesis, especially in the leaves, and it is suggested that the phenyl-propanoid synthesis pathway is responsible for the accumulation of SA observed after cadmium stress. Cadmium influenced the synthesis and activation of protective compounds to varying extents in wheat genotypes with different levels of tolerance; the roots and leaves also responded differently to cadmium stress. Although a direct relationship was not found between the initial SA levels and the degree of cadmium tolerance, the results suggest that the increase in the root SA level during cadmium stress in the Mv varieties could be related with the enhancement of the internal glutathione cycle, thus inducing the antioxidant and metal detoxification systems, which promote Cd stress tolerance in wheat seedlings. The positive correlation between certain SA-related compounds and protective compounds suggests that SA-related signalling may also play a role in the acclimation to heavy metal stress

  13. Synthesis and role of salicylic acid in wheat varieties with different levels of cadmium tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, Viktória; Gondor, Orsolya K.; Szalai, Gabriella; Darkó, Éva; Majláth, Imre; Janda, Tibor; Pál, Magda, E-mail: pal.magda@agrar.mta.hu

    2014-09-15

    Highlights: • Cd induces the salicylic acid metabolism in wheat. • Salicylic acid is synthesized via benzoic acid and/or ortho-hydroxy-cinnamic acid. • Cd tolerance can be explained by the highly induced glutathione metabolism. • Salicylic acid signalling is correlated with glutathione-related mechanisms. - Abstract: Wheat genotypes with different endogenous SA contents were investigated, in order to reveal how cadmium influences salicylic acid (SA) synthesis, and to find possible relationships between SA and certain protective compounds (members of the antioxidants and the heavy metal detoxification system) and between the SA content and the level of cadmium tolerance. Cadmium exposure induced SA synthesis, especially in the leaves, and it is suggested that the phenyl-propanoid synthesis pathway is responsible for the accumulation of SA observed after cadmium stress. Cadmium influenced the synthesis and activation of protective compounds to varying extents in wheat genotypes with different levels of tolerance; the roots and leaves also responded differently to cadmium stress. Although a direct relationship was not found between the initial SA levels and the degree of cadmium tolerance, the results suggest that the increase in the root SA level during cadmium stress in the Mv varieties could be related with the enhancement of the internal glutathione cycle, thus inducing the antioxidant and metal detoxification systems, which promote Cd stress tolerance in wheat seedlings. The positive correlation between certain SA-related compounds and protective compounds suggests that SA-related signalling may also play a role in the acclimation to heavy metal stress.

  14. Synthesis and biological properties of amino acids and peptides containing a tetrazolyl moiety

    Science.gov (United States)

    Popova, E. A.; Trifonov, R. E.

    2015-09-01

    Literature data published mainly in the last 15 years on the synthesis and biological properties of amino acid analogues and derivatives containing tetrazolyl moieties are analyzed. Tetrazolyl analogues and derivatives of amino acids and peptides are shown to be promising for medicinal chemistry. Being polynitrogen heterocyclic systems comprising four endocyclic nitrogen atoms, tetrazoles can behave as acids and bases and form strong hydrogen bonds with proton donors (more rarely, with acceptors). They have high metabolic stability and are able to penetrate biological membranes. The review also considers the synthesis and properties of linear and cyclic peptides based on modified amino acids incorporating a tetrazolyl moiety. A special issue is the discussion of the biological properties of tetrazole-containing amino acids and peptides, which exhibit high biological activity and can be used to design new drugs. The bibliography includes 200 references.

  15. A Green Synthesis of Diisopropyl Phosphoryl Amino Acid

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we report that diisopropyl phosphoryl amino acid could be prepared with reasonable yields under solvent-free condition by adding amino acid to the mixture of diisopropyl phosphite and N-chlorodiisopropylamine.

  16. Synthesis and identification of dinitro- and diaminoterephthalic acid

    Institute of Scientific and Technical Information of China (English)

    M. Ghaemy; H. Mighani

    2009-01-01

    Dinitroterephthalic acid (DNTPA) and diaminoterephthalic acid (DATPA) were prepared in 85% and 75% yields, respectively. These compounds were characterized by using FTIR and IHNMR. DATPA can be used as a monomer for the preparation of polyesters and polyamides.

  17. Absence of cholesterol synthesis as contrasted with the presence of fatty acid synthesis in some arthropods

    NARCIS (Netherlands)

    Zandee, D.I.

    1967-01-01

    1. 1. After administration of acetate-1-14C absence of cholesterol synthesis was demonstrated in the lobster Homarus gammarus (L.), the spider Avicularia avicularia (L.) and in the millepede Graphidostreptus tumuliporus (Karsch). 2. 2. However, the animals utilize acetate for the synthesis of fatty

  18. Synthesis of protected (2S,4R)-2-amino-4-methyldecanoic acid, a proposed component of culicinins

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Tian Tian Sun; Duo Mei; Jun Fei Wang; Ying Xia Li

    2008-01-01

    The protected (2S,4R)-2-amino-4-methyldecanoic acid, a proposed component of culicinins has been synthesized over 10 steps and in total 28% yields using Wittig reaction and Schollkopf amino acid synthesis as key steps.

  19. Retinoic Acid Synthesis and Signaling during Early Organogenesis

    OpenAIRE

    Duester, Gregg

    2008-01-01

    Retinoic acid, a derivative of vitamin A, is an essential component of cell-cell signaling during vertebrate organogenesis. In early development retinoic acid functions as a trunk organizer by providing an instructive signal for posterior neuroectoderm and foregut endoderm and a permissive signal for trunk mesoderm differentiation. At later stages, retinoic acid contributes to the development of the eye and other organs. Recent efforts suggest that retinoic acid acts primarily in a paracrine ...

  20. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

    Science.gov (United States)

    Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

    2011-01-01

    A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

  1. Synthesis of alpha-hydroxyphosphonic acids from Lesquerella oil

    Science.gov (United States)

    Lesquerella oil has been a substance of growing chemical interest, due to the ease with which it is produced and its similarity in structure to castor oil. The primary fatty acid in Lesquerella oil, lesquerolic acid, is very similar to the principal component of castor oil, ricinoleic acid, and may ...

  2. A Convenient Synthesis of Amino Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-05-01

    Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

  3. Myristic acid potentiates palmitic acid-induced lipotoxicity and steatohepatitis associated with lipodystrophy by sustaning de novo ceramide synthesis.

    Science.gov (United States)

    Martínez, Laura; Torres, Sandra; Baulies, Anna; Alarcón-Vila, Cristina; Elena, Montserrat; Fabriàs, Gemma; Casas, Josefina; Caballeria, Joan; Fernandez-Checa, Jose C; García-Ruiz, Carmen

    2015-12-01

    Palmitic acid (PA) induces hepatocyte apoptosis and fuels de novo ceramide synthesis in the endoplasmic reticulum (ER). Myristic acid (MA), a free fatty acid highly abundant in copra/palmist oils, is a predictor of nonalcoholic steatohepatitis (NASH) and stimulates ceramide synthesis. Here we investigated the synergism between MA and PA in ceramide synthesis, ER stress, lipotoxicity and NASH. Unlike PA, MA is not lipotoxic but potentiated PA-mediated lipoapoptosis, ER stress, caspase-3 activation and cytochrome c release in primary mouse hepatocytes (PMH). Moreover, MA kinetically sustained PA-induced total ceramide content by stimulating dehydroceramide desaturase and switched the ceramide profile from decreased to increased ceramide 14:0/ceramide16:0, without changing medium and long-chain ceramide species. PMH were more sensitive to equimolar ceramide14:0/ceramide16:0 exposure, which mimics the outcome of PA plus MA treatment on ceramide homeostasis, than to either ceramide alone. Treatment with myriocin to inhibit ceramide synthesis and tauroursodeoxycholic acid to prevent ER stress ameliorated PA plus MA induced apoptosis, similar to the protection afforded by the antioxidant BHA, the pan-caspase inhibitor z-VAD-Fmk and JNK inhibition. Moreover, ruthenium red protected PMH against PA and MA-induced cell death. Recapitulating in vitro findings, mice fed a diet enriched in PA plus MA exhibited lipodystrophy, hepatosplenomegaly, increased liver ceramide content and cholesterol levels, ER stress, liver damage, inflammation and fibrosis compared to mice fed diets enriched in PA or MA alone. The deleterious effects of PA plus MA-enriched diet were largely prevented by in vivo myriocin treatment. These findings indicate a causal link between ceramide synthesis and ER stress in lipotoxicity, and imply that the consumption of diets enriched in MA and PA can cause NASH associated with lipodystrophy.

  4. Synthesis and spectroscopic characterization of fluorescent solid rare earth complexes with hydroxamic acids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The complexes RE2(DHYA)3 .nH2O in the title bar were synthesized through some reactions oftrivalent rareearth ions. In the process of synthesis, dihydroxamic acids were taken as ligands while the alcohol was taken as a solvent.The ligands included adipylhydroxamic acid (ADHA), p-phthalichydroxamic acid (PPHA), oxalohydroxamic acid (OXHA), butadihydroxamic acid (BDHA), o-phthalichydroxamic acid (OPHA), benzoylhydroxamic acid (BHA), etc.Measured at 25 ℃, the molar conductances in various modes are 13.00-21.05 S. cm2. mol-1, which shows that rare-earth complexes are nonelectrolytes and the hydroxamino groups of the complexes have taken part in bonding. Infrared spectra, ultraviolet spectra, nuclear magnetic resonance (1HNMR) spectra, and fluorescence spectra were used to investigate the complexes. Experiments have proved that the complexes of Eu3+ and Tb3+ with aromatic hydroxamic acids have good fluorescent characteristics.

  5. Characterisation of Fecal Soap Fatty Acids, Calcium Contents, Bacterial Community and Short-Chain Fatty Acids in Sprague Dawley Rats Fed with Different sn-2 Palmitic Triacylglycerols Diets

    Science.gov (United States)

    Wan, Jianchun; Hu, Songyou; Ni, Kefeng; Chang, Guifang; Sun, Xiangjun; Yu, Liangli

    2016-01-01

    The structure of dietary triacylglycerols is thought to influence fatty acid and calcium absorption, as well as intestinal microbiota population of the host. In the present study, we investigated the impact of palmitic acid (PA) esterified at the sn-2 position on absorption of fatty acid and calcium and composition of intestinal microorganisms in rats fed high-fat diets containing either low sn-2 PA (12.1%), medium sn-2 PA (40.4%) or high sn-2 PA (56.3%), respectively. Fecal fatty acid profiles in the soaps were measured by gas chromatography (GC), while fecal calcium concentration was detected by ICP-MS. The fecal microbial composition was assessed using a 16S rRNA high-throughput sequencing technology and fecal short-chain fatty acids were detected by ion chromatograph. Dietary supplementation with a high sn-2 PA fat significantly reduced total fecal contents of fatty acids soap and calcium compared with the medium or low sn-2 PA fat groups. Diet supplementation with sn-2 PA fat did not change the entire profile of the gut microbiota community at phylum level and the difference at genera level also were minimal in the three treatment groups. However, high sn-2 PA fat diet could potentially improve total short-chain fatty acids content in the feces, suggesting that high dietary sn-2 PA fat might have a beneficial effect on host intestinal health. PMID:27783700

  6. Electroenzymatic strategies for deracemization, stereoinversion and asymmetric synthesis of amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Maerkle, Wolfgang [Institut fuer Biotechnologie 2, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany); Luetz, Stephan [Institut fuer Biotechnologie 2, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany)], E-mail: s.luetz@fz-juelich.de

    2008-02-25

    A combination of a selective enzymatic oxidation with an unselective electrochemical reduction step was applied for deracemization, stereoinversion and asymmetric synthesis of L-leucine (starting from racemic leucine, D-leucine or 4-methyl-2-oxovaleric acid) in a batch reactor. D-Amino acid oxidase (D-AAO) from Trigonopsis variabilis was used as enzyme. Reaction conditions for the electrochemical and enzymatic reactions were investigated separately and finally combined to an electroenzymatic synthesis, yielding 3.5 mmol L{sup -1} d{sup -1} of L-leucine (ee 91%)

  7. Quantitative Proteomics: Measuring Protein Synthesis Using 15N Amino Acids Labeling in Pancreas Cancer Cells

    OpenAIRE

    Zhao, Yingchun; Lee, Wai-Nang Paul; Lim, Shu; Go, Vay Liang; Xiao, Jing; Cao, Rui; Zhang, Hengwei; Recker, Robert; Xiao, Gary Guishan

    2009-01-01

    Pancreatic cancer MIA PaCa cells were cultured in the presence and absence of 15N amino acids mixture for 72 hours. During protein synthesis, the incorporation of 15N amino acids results in a new mass isotopomer distribution in protein, which is approximated by the concatenation of two binomial distributions of 13C and 15N. Fraction of protein synthesis (FSR) can thus be determined from the relative intensities of the ‘labeled’ (new) and the ‘unlabeled” (old) spectra. Six prominent spots were...

  8. Communic Acids: Occurrence, Properties and Use as Chirons for the Synthesis of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Alejandro F. Arteaga

    2012-02-01

    Full Text Available Communic acids are diterpenes with labdane skeletons found in many plant species, mainly conifers, predominating in the genus Juniperus (fam. Cupresaceae. In this review we briefly describe their distribution and different biological activities (anti- bacterial, antitumoral, hypolipidemic, relaxing smooth muscle, etc.. This paper also includes a detailed explanation of their use as chiral building blocks for the synthesis of bioactive natural products. Among other uses, communic acids have proven useful as chirons for the synthesis of quassinoids (formal, abietane antioxidants, ambrox and other perfume fixatives, podolactone herbicides, etc., featuring shorter and more efficient processes.

  9. Synthesis and mesomorphic behaviour of lithocholic acid derivatives

    Indian Academy of Sciences (India)

    V A E Shaikh; N N Maldar; S V Lonikar

    2003-08-01

    A series of liquid crystalline derivatives of lithocholic acid were prepared using simple chemical reactions involving the terminal functional group—hydroxyl at C-3 and/or carboxyl at C-24. Thus methyl -3-(3-carboxy propionyl) lithocholate (I), 3-(3-carboxy propionyl) lithocholic acid (II), 3-acetyl lithocholic acid (III), 3-propionyl lithocholic acid (IV), 3-benzoyl lithocholic acid (V), 3-(4-nitrobenzoyl) lithocholic acid (VI), 3-cinnamoyl lithocholic acid (VII), methyl-3-(4-nitrobenzoyl) lithocholate (VIII) and 1,4-bis [cholan-24-methoxy carbonyl-3-oxycarbonyl] butane (IX) were prepared in good yields and characterized by IR, NMR and polarizing optical microscopy. Compounds (I) and (IX) exhibited monotropic behaviour while the others were enantiotropic. Some of the compounds also showed a high tendency of super cooling. Compounds (V), (VI) and (IX) formed cholesteric phase while the remaining compounds displayed smectic phase.

  10. Characterising pharmacological ligands to study the long chain fatty acid receptors GPR40/FFA1 and GPR120/FFA4

    DEFF Research Database (Denmark)

    Milligan, G; Alvarez-Curto, E; Watterson, K R;

    2015-01-01

    The G protein-coupled receptors FFA1 (previously designated GPR40) and FFA4 (previously GPR120) are both activated by saturated and unsaturated longer-chain free fatty acids. With expression patterns and functions anticipated to directly or indirectly promote insulin secretion, provide homeostatic...... control of blood glucose and improve tissue insulin sensitivity, both receptors are being studied as potential therapeutic targets for the control of type II diabetes. Furthermore, genetic and systems biology studies in both humans and mouse models link FFA4 to diabetes and obesity. Although activated...... of the sphingosine 1 phosphate receptor S1P1 . Screening and subsequent medicinal chemistry programmes have developed a number of FFA1 selective agonists that are effective in promoting insulin secretion in a glucose concentration-dependent manner, and in lowering blood glucose levels. However, the recent...

  11. The synthesis of astaxanthin esters,independent of the formation of cysts,highly correlates with the synthesis of fatty acids in Haematococcus pluvialis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty acids, though it is an well known phenomenon that the accumulation of astaxanthin is usually accompanied by the formation of cyst. The red cysts contain more than 30% of fatty acids, with 81% of the unsaturated fatty acids. Taken together, besides a resource of astaxanthin, H. pluvialis would be a good resource of valuable fatty acids.

  12. Racemic synthesis and solid phase peptide synthesis application of the chimeric valine/leucine derivative 2-amino-3,3,4-trimethyl-pentanoic acid.

    Science.gov (United States)

    Pelà, M; Del Zoppo, L; Allegri, L; Marzola, E; Ruzza, C; Calo, G; Perissutti, E; Frecentese, F; Salvadori, S; Guerrini, R

    2014-07-01

    The synthesis of non natural amino acid 2-amino-3,3,4-trimethyl-pentanoic acid (Ipv) ready for solid phase peptide synthesis has been developed. Copper (I) chloride Michael addition, followed by a Curtius rearrangement are the key steps for the lpv synthesis. The racemic valine/leucine chimeric amino acid was then successfully inserted in position 5 of neuropeptide S (NPS) and the diastereomeric mixture separated by reverse phase HPLC. The two diastereomeric NPS derivatives were tested for intracellular calcium mobilization using HEK293 cells stably expressing the mouse NPS receptor where they behaved as partial agonist and pure antagonist.

  13. Relationship of lipogenic enzyme activities to the rate of rat liver fatty acid synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, G.; Kelley, D.; Schmidt, P.; Virk, S.; Serrato, C.

    1986-05-01

    The mechanism by which diet regulates liver lipogenesis is unclear. Here the authors report how dietary alterations effect the activities of key enzymes of fatty acid (FA) synthesis. Male Sprague-Dawley rats, 400-500 g, were fasted for 48h and then refed a fat-free, high carbohydrate (HC) diet (75% cal. from sucrose) for 0,3,9,24 and 48h, or refed a HC diet for 48h, then fed a high-fat (HF) diet (44% cal. from corn oil) for 3,9,24 and 48h. The FA synthesis rate and the activities of acetyl CoA carboxylase (AC), fatty acid synthase (FAS), ATP citrate lyase (CL), and glucose 6-phosphate dehydrogenase (G6PDH) were determined in the livers. FA synthesis was assayed with /sup 3/H/sub 2/O, enzyme activities were measured spectrophotometrically except for AC which was assayed with /sup 14/C-bicarbonate. There was no change in the activity of AC during fasting or on the HC diet. Fasting decreased the rate of FA synthesis by 25% and the activities of FAS and CL by 50%; refeeding the HC diet induced parallel changes in FA synthesis and the activities of FAS, CL, and G6PDH. After 9h on the HF diet, FA synthesis had decreased sharply, AC activity increased significantly while no changes were detected in the other activities. Subsequently FA synthesis did not change while the activities of the enzymes decreased slowly. These enzymes did not appear to regulate FA synthesis during inhibition of lipogenesis, but FAS, CL or G6PDH may be rate limiting in the induction phase. Other key factors may regulate FA synthesis during dietary alterations.

  14. Amino acid starvation has opposite effects on mitochondrial and cytosolic protein synthesis.

    Directory of Open Access Journals (Sweden)

    Mark A Johnson

    Full Text Available Amino acids are essential for cell growth and proliferation for they can serve as precursors of protein synthesis, be remodelled for nucleotide and fat biosynthesis, or be burnt as fuel. Mitochondria are energy producing organelles that additionally play a central role in amino acid homeostasis. One might expect mitochondrial metabolism to be geared towards the production and preservation of amino acids when cells are deprived of an exogenous supply. On the contrary, we find that human cells respond to amino acid starvation by upregulating the amino acid-consuming processes of respiration, protein synthesis, and amino acid catabolism in the mitochondria. The increased utilization of these nutrients in the organelle is not driven primarily by energy demand, as it occurs when glucose is plentiful. Instead it is proposed that the changes in the mitochondrial metabolism complement the repression of cytosolic protein synthesis to restrict cell growth and proliferation when amino acids are limiting. Therefore, stimulating mitochondrial function might offer a means of inhibiting nutrient-demanding anabolism that drives cellular proliferation.

  15. Physical Characterisation as an Insight into a Gene Delivery System Containing Cyclodextrins with Pluronic®-F127 and Folic acid as Non-Viral Vectors.

    Science.gov (United States)

    Eng, Matthew; Elkordy, Amal A; McCarron, Paul A; Elkordy, Eman A; Faheem, Ahmed

    2014-01-01

    Gene delivery into cells offers opportunities to treat various human genetic diseases. Effective gene delivery is dependent on its stability and ability to transfect across cells. DNA is susceptible to enzymatic degradation and its negatively charge are barriers towards successful transfection. DNA has to be protected from degradation and neutralised. Non-viral vectors are preferred carrier systems, therefore, the use of cyclodextrins with Pluronic(®)-F127 and folic acid at different concentrations to stabilise the formulation was investigated. Formulations were characterised in fresh and freeze dried forms. DNA stability in formulations was tested by determining the stability of DNA against enzymatic degradation. Degree of DNA inclusion into cyclodextrins was investigated using fluorescence spectroscopy. Thermal behaviour was studied using Differential Scanning Calorimetry (DSC). Incorporation of Pluronic(®)-F127 produced most stable formulations regarding enzymatic degradation. These formulations show high percentage inclusion. Shift of peaks in FTIR data, appearance of uniform particulate as detected by SEM and changing in the denaturation temperature as demonstrated by DSC data for Pluronic(®)-F127 containing formulations confirm clear interaction between Pluronic(®)-F127 and cyclodextrin/ DNA complex. It was noted that γ-cyclodextrin provide better protection and inclusion compared to β-cyclodextrin. Pluronic(®)-F127 with cyclodextrins is a promising combination to improve stability.

  16. Photochemical Synthesis of the Bioconjugate Folic Acid-Gold Nanoparticles

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Bertel, Linda; Páez-Mozo, Edgar;

    2013-01-01

    In this paper we present a rapid and simple onepot method to obtain gold nanoparticles functionalized with folic acid using a photochemistry method. The bioconjugate folic acid-gold nanoparticle was generated in one step using a photo-reduction method, mixing hydrogen tetrachloroaurate with folic...... at 4°C prolongs the stability of folic acid-gold nanoparticle suspensions to up to 26 days. Ultraviolet visible and Fourier transform infrared spectroscopy showed a surface plasmon band of around 534nm and fluorescence spectroscopy exhibited a quenching effect on gold nanoparticles in the fluorescence...... emission of folic acid and thus confirmed the conjugation of folic acid to the surface of gold nanoparticles. In this study we demonstrate the use of a photochemistry method to obtain folic acid-gold nanoparticles in a simple and rapid way without the use of surfactants and long reaction times...

  17. Retinoic acid synthesis and functions in early embryonic development

    OpenAIRE

    Kam Richard Kin Ting; Deng Yi; Chen Yonglong; Zhao Hui

    2012-01-01

    Abstract Retinoic acid (RA) is a morphogen derived from retinol (vitamin A) that plays important roles in cell growth, differentiation, and organogenesis. The production of RA from retinol requires two consecutive enzymatic reactions catalyzed by different sets of dehydrogenases. The retinol is first oxidized into retinal, which is then oxidized into RA. The RA interacts with retinoic acid receptor (RAR) and retinoic acid X receptor (RXR) which then regulate the target gene expression. In thi...

  18. Synthesis and photophysical studies of new pyrenylamino acids

    OpenAIRE

    Pereira, Goreti; Castanheira, Elisabete M. S.; Schellenberg, Peter Michael; Belsley, M.; Ferreira, Paula M. T.; Monteiro, Luís S.

    2013-01-01

    Two new pyrenylamino acid derivatives were synthesized from beta-bromodehydroalanine derivatives in good yields using addition and elimination reactions. The photophysical properties of the two new pyrenylamino acids were studied in several solvents. Steady-state and time-resolved fluorescence measurements revealed that the bipyrenylamino acid undergoes excimer formation, this process being solvent dependent. Rate constants for excimer formation and dissociation were calculated. The monopy...

  19. A Novel Synthesis of β-Hydroxy-α-amino Acids

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Hui; LI Shuo; XU Pen-gFei

    2003-01-01

    @@ β-hydroxy-α-amino acids constitute an important class of compounds as naturally occurring amino acids and as components of many complex natural products possessing a wide range of biological activities. [1] As a consequence of the essential role played by these amino acids in the biological systems and their utility as synthetic building blocks, a number of useful strategies have been devised for their preparation. [2

  20. Modulation by Amino Acids: Toward Superior Control in the Synthesis of Zirconium Metal-Organic Frameworks.

    Science.gov (United States)

    Gutov, Oleksii V; Molina, Sonia; Escudero-Adán, Eduardo C; Shafir, Alexandr

    2016-09-12

    The synthesis of zirconium metal-organic frameworks (Zr MOFs) modulated by various amino acids, including l-proline, glycine, and l-phenylalanine, is shown to be a straightforward approach toward functional-group incorporation and particle-size control. High yields in Zr-MOF synthesis are achieved by employing 5 equivalents of the modulator at 120 °C. At lower temperatures, the method provides a series of Zr MOFs with increased particle size, including many suitable for single-crystal X-ray diffraction studies. Furthermore, amino acid modulators can be incorporated at defect sites in Zr MOFs with an amino acid/ligand ratio of up to 1:1, depending on the ligand structure and reaction conditions. The MOFs obtained through amino acid modulation exhibit an improved CO2 -capture capacity relative to nonfunctionalized materials.

  1. Increased Production of Fatty Acids and Triglycerides in Aspergillus oryzae by Enhancing Expressions of Fatty Acid Synthesis-Related Genes

    Energy Technology Data Exchange (ETDEWEB)

    Tamano, Koichi; Bruno, Kenneth S.; Karagiosis, Sue A.; Culley, David E.; Deng, Shuang; Collett, James R.; Umemura, Myco; Koike, Hideaki; Baker, Scott E.; Machida, Masa

    2013-01-01

    Microbial production of fats and oils is being developedas a means of converting biomass to biofuels. Here we investigate enhancing expression of enzymes involved in the production of fatty acids and triglycerides as a means to increase production of these compounds in Aspergillusoryzae. Examination of the A.oryzaegenome demonstrates that it contains twofatty acid synthases and several other genes that are predicted to be part of this biosynthetic pathway. We enhancedthe expressionof fatty acid synthesis-related genes by replacing their promoters with thepromoter fromthe constitutively highly expressedgene tef1. We demonstrate that by simply increasing the expression of the fatty acid synthasegenes we successfullyincreasedtheproduction of fatty acids and triglyceridesby more than two fold. Enhancement of expression of the fatty acid pathway genes ATP-citrate lyase and palmitoyl-ACP thioesteraseincreasedproductivity to a lesser extent.Increasing expression ofacetyl-CoA carboxylase caused no detectable change in fatty acid levels. Increases in message level for each gene were monitored usingquantitative real-time RT-PCR. Our data demonstrates that a simple increase in the abundance of fatty acid synthase genes can increase the detectable amount of fatty acids.

  2. Polymers from fatty acids: poly(ω-hydroxyl tetradecanoic acid) synthesis and physico-mechanical studies.

    Science.gov (United States)

    Liu, Chen; Liu, Fei; Cai, Jiali; Xie, Wenchun; Long, Timothy E; Turner, S Richard; Lyons, Alan; Gross, Richard A

    2011-09-12

    This Article describes the synthesis and physicomechanical properties of bioplastics prepared from methyl ω-hydroxytetradecanoic acid (Me-ω-OHC14), a new monomer available by a fermentation process using an engineered Candida tropicalis strain. Melt-condensation experiments were conducted using titanium tetraisopropoxide (Ti[OiPr](4)) as a catalyst in a two-stage polymerization (2 h at 200 °C under N(2), 4 h at 220 °C under 0.1 mmHg). Poly(ω-hydroxytetradecanoate), P(ω-OHC14), M(w), determined by SEC-MALLS, increased from 53K to 110K as the Ti(OiPr)(4) concentration increased from 50 to 300 ppm. By varying the polymerization conditions (catalyst concentration, reaction time, second-stage reaction temperature) a series of P(ω-OHC14) samples were prepared with M(w) values from 53K to 140K. The synthesized polyesters with M(w) ranging from 53K to 140K were subjected to characterization by DSC, TGA, DMTA, and tensile testing. Influences of P(ω-OHC14) molecular weight, melting point, and enthalpies of melting/crystallization on material tensile properties were explored. Cold-drawing tensile tests at room temperature for P(ω-OHC14) with M(w) 53K-78K showed a brittle-to-ductile transition. In contrast, P(ω-OHC14) with M(w) 53K undergoes brittle fracture. Increasing P(ω-OHC14) M(w) above 78K resulted in a strain-hardening phenomena and tough properties with elongation at break ~700% and true tensile strength of ~50 MPa. Comparisons between high density polyethylene and P(ω-OHC14) mechanical and thermal properties as a function of their respective molecular weights are discussed. PMID:21793591

  3. Synthesis and Quantitative Structure-Property Relationships of Side Chain-Modified Hyodeoxycholic Acid Derivatives

    OpenAIRE

    Antimo Gioiello; Antonio Macchiarulo; Roberto Pellicciari; Roberto Nuti; Roccaldo Sardella; Benedetto Natalini; Paola Sabbatini; Paolo Filipponi

    2013-01-01

    Bile acids have emerged as versatile signalling compounds of a complex network of nuclear and membrane receptors regulating various endocrine and paracrine functions. The elucidation of the interconnection between the biological pathways under the bile acid control and manifestations of hepatic and metabolic diseases have extended the scope of this class of steroids for in vivo investigations. In this framework, the design and synthesis of novel biliary derivatives able to modulate a specific...

  4. One-pot Synthesis of Lewis Acidic Ionic Liquids for Friedel-Crafts Alkylation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. The ionic liquids were used as catalyst for Friedel-Crafts alkylation of benzene and 1-dodecene. The turnovers of 1-dodecene were higher than 99%. Monoalkylbenzene selectivity was 98%, while the 2-substituent product selectivity was 45%.

  5. Synthesis of 2-[11C]cyano-isonicotinic acid hydrazide

    International Nuclear Information System (INIS)

    Isonicotinic acid hydrazide (isoniazid), a drug used in treating tuberculosis has been labelled with carbon-11 at the 2-position. The labelling synthesis starts with methyl isonicotinate treated with dimethyl sulfate. The resulting salt solution is loaded onto silica gel and dried, followed by treatment with carbon-11 labelled hydrocyanic acid. Work-up gave the labelled compound with an average 32% radiochemical yield. Subsequent treatment with hydrazine hydrate yielded isoniazid

  6. Polyphosphorous acid catalyzed cyclization in the synthesis of cryptolepine derivatives

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    11-Oxo-10,11-dihydroxy-5H-indolo[3,2,b]quinoline7-carboxylic acid was obtained specifically by polyphosphorous acid catalyzed cyclization with optimal reaction conditions. Biological assays showed that it potentially inhibits the proteasomal chymotrypsin-like activity in vitro and suppresses breast cancer cell growth.

  7. Improved synthesis of isostearic acid using zeolite catalysts

    Science.gov (United States)

    Isostearic acids are unique and important biobased products with superior properties. Unfortunately, they are not widely utilized in industry because they are produced as byproducts from a process called clay-catalyzed oligomerization of tall oil fatty acids. Generally, this clay method results in...

  8. Differential regulation of protein synthesis by amino acids and insulin in peripheral and visceral tissues of neonatal pigs.

    Science.gov (United States)

    Suryawan, Agus; O'Connor, Pamela M J; Bush, Jill A; Nguyen, Hanh V; Davis, Teresa A

    2009-05-01

    The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are maximally stimulated after feeding. In the current study, we examined the individual roles of amino acids and insulin in the regulation of protein synthesis in peripheral and visceral tissues of the neonate by performing pancreatic glucose-amino acid clamps in overnight-fasted 7-day-old pigs. We infused pigs (n = 8-12/group) with insulin at 0, 10, 22, and 110 ng kg(-0.66) min(-1) to achieve approximately 0, 2, 6 and 30 muU ml(-1) insulin so as to simulate below fasting, fasting, intermediate, and fed insulin levels, respectively. At each insulin dose, amino acids were maintained at the fasting or fed level. In conjunction with the highest insulin dose, amino acids were also allowed to fall below the fasting level. Tissue protein synthesis was measured using a flooding dose of L: -[4-(3)H] phenylalanine. Both insulin and amino acids increased fractional rates of protein synthesis in longissimus dorsi, gastrocnemius, masseter, and diaphragm muscles. Insulin, but not amino acids, increased protein synthesis in the skin. Amino acids, but not insulin, increased protein synthesis in the liver, pancreas, spleen, and lung and tended to increase protein synthesis in the jejunum and kidney. Neither insulin nor amino acids altered protein synthesis in the stomach. The results suggest that the stimulation of protein synthesis by feeding in most tissues of the neonate is regulated by the post-prandial rise in amino acids. However, the feeding-induced stimulation of protein synthesis in skeletal muscles is independently mediated by insulin as well as amino acids.

  9. Isolation and characterisation of 8-hydroxy-3Z,5Z-tetradecadienoic acid, a putative intermediate in Pichia guilliermondii gamma-decalactone biosynthesis from ricinoleic acid.

    Science.gov (United States)

    Iacazio, G; Martini, D; Faure, B; N'Guyen, M H

    2002-03-19

    During a screening procedure for the discovery of a strong gamma-decalactone producer from ricinoleic acid, we observed that the yeast Pichia guilliermondii accumulated transiently 8-hydroxy-3Z,5Z-tetradecadienoic acid 1 during gamma-decalactone biosynthesis in the stationary phase of growth. The structural elucidation of 1 was based on nuclear magnetic resonance, infrared, ultraviolet and gas chromatography-mass spectrometry experiments. The occurrence of 1 is discussed in relation with previously proposed gamma-decalactone biosynthetic pathways. PMID:12007654

  10. Synthesis of quinoxalines in the presence of heteropoly acids

    Directory of Open Access Journals (Sweden)

    Fatemeh Hakimia

    2013-04-01

    Full Text Available Efficient synthesis of quinoxaline derivatives from the reaction of α-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced.

  11. Easy synthesis of graphene sheets from alfalfa plants by treatment of nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jiao, E-mail: qujiao@bhu.edu.cn [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013 (China); School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China); Luo, Chunqiu, E-mail: fplj_lcq@163.com [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013 (China); Zhang, Qian; Cong, Qiao [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013 (China); Yuan, Xing [School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China)

    2013-04-01

    Highlights: ► An easy method for synthesis of graphene sheets using alfalfa plants was introduced. ► An novelty formation mechanism of graphene sheets using alfalfa plants was proposed. ► This method exploits a new carbon source and provides a novel idea to synthesize graphene sheets. -- Abstract: This letter focuses on synthesis of graphene sheets from alfalfa plants by treatment of nitric acid. The transmission electron microscopy image (TEM) demonstrates that the graphene sheets are agglomerated and overlapped, the energy dispersive spectrum (EDS) indicates that the products are pure, and the Raman spectrum shows the graphene sheets are well graphitized. In addition, the formation mechanism of the graphene sheets from alfalfa plants by treatment nitric acid is discussed. These findings inspire the search for a new strategy for synthesis of graphene sheets from renewable natural products, and the lower cost of this new process and carbon source may facilitate industrial production.

  12. Synthesis and characterisation of nitrogen poly-heterocyclic molecules using as selective complexing agents of metallic cations; Synthese et caracterisation de molecules polyheterocycliques azotees utilisables en tant que complexants selectifs de cations metalliques

    Energy Technology Data Exchange (ETDEWEB)

    Alphonse, F.A

    2003-12-15

    Separation of actinides (III) from lanthanides (III) is a crucial problem in the reprocessing of used nuclear fuels. Experimental results shown that soft donor extractants such as nitrogen polydentate heterocycles containing a NCCNCCN coordination site are potentials ligands for selective extraction of actinides (III). In those cases, two types of liquid-liquid extractions are employed: synergistic combination with lipophilic acid extractants and direct extraction. On the basis of the Hard and Soft Acids and Bases theory and basicity evaluation, new extractants were defined. We have first studied the synthesis of potential 1,3,5-triazine ligands designed for extraction in synergy with {alpha}-bromodecanoic acid. Secondly, we have examined the synthesis of bis-triazinyl-pyridine ligands for direct extraction studies. Extraction tests were carried out and perspectives of synthesis were deducted from those extraction results. (author)

  13. Asymmetric synthesis of aromatic β-amino acids using ω-transaminase: Optimizing the lipase concentration to obtain thermodynamically unstable β-keto acids.

    Science.gov (United States)

    Mathew, Sam; Jeong, Seong-Su; Chung, Taeowan; Lee, Sang-Hyeup; Yun, Hyungdon

    2016-01-01

    Synthesized aromatic β-amino acids have recently attracted considerable attention for their application as precursors in many pharmacologically relevant compounds. Previous studies on asymmetric synthesis of aromatic β-amino acids using ω-transaminases could not be done efficiently due to the instability of β-keto acids. In this study, a strategy to circumvent the instability problem of β-keto acids was utilized to generate β-amino acids efficiently via asymmetric synthesis. In this work, thermodynamically stable β-ketoesters were initially converted to β-keto acids using lipase, and the β-keto acids were subsequently aminated using ω-transaminase. By optimizing the lipase concentration, we successfully overcame the instability problem of β-keto acids and enhanced the production of β-amino acids. This strategy can be used as a general approach to efficiently generate β-amino acids from β-ketoesters.

  14. Lipase-catalyzed synthesis of oligoesters of 2,5-furandicarboxylic acid with aliphatic diols

    NARCIS (Netherlands)

    Cruz-Izquierdo, Álvaro; Broek, van den Lambertus A.M.; Serra, Juan L.; Llama, María J.; Boeriu, Carmen G.

    2015-01-01

    2,5-Furandicarboxylic acid is a platform chemical for the production of biobased polymers and materials. This study reports the synthesis of furan oligoesters via polytransesterification of dimethyl furan-2,5-dicarboxylate and linear α, ω-aliphatic diols with chain length ranging from C2 to C12,

  15. Phosphotungstic Acid: An Efficient, Cost-effective and Recyclable Catalyst for the Synthesis of Polysubstituted Quinolines

    Directory of Open Access Journals (Sweden)

    Sahareh Bashiribod

    2009-03-01

    Full Text Available Phosphotungstic acid (H3PW12O40 was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedländer condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions.

  16. Insulin and amino acids stimulate whole body protein synthesis in neonates

    Science.gov (United States)

    Insulin and amino acids (AA) stimulate muscle protein synthesis in neonatal pigs. To determine the effects of insulin and AA on whole body protein turnover, hyperinsulinemic (0 and 100 ng/(kg[0.66]/min))-euglycemic-AA clamps were performed during euaminoacidemia or hyperaminoacidemia in fasted 7-d-...

  17. The first total synthesis of the novel triquinane natural products pleurotellol and pleurotellic acid

    OpenAIRE

    Mehta, Goverdhan; Murthy, Sai Krishna A

    2003-01-01

    The first total synthesis of the triquinane based sesquiterpenoid antibiotics (±)-pleurotellol and (±)-pleurotellic acid isolated from the fermentation broth of Pleurotellus hypnophilus have been accomplished. The triquinane based bis-enone system obtained via photo-thermal metathesis in a caged pentacyclic dione has been elaborated to the natural products through carefully crafted functional group transformations.

  18. Silica Sulfuric Acid: An Eco-Friendly and Reusable Catalyst for Synthesis of Benzimidazole Derivatives

    Directory of Open Access Journals (Sweden)

    Bahareh Sadeghi

    2013-01-01

    Full Text Available Silica sulfuric acid (SiO2-OSO3H as an eco-friendly, readily available, and reusable catalyst is applied to benzimidazole derivatives synthesis under reflux in ethanol. The procedure is very simple and the products are isolated with an easy workup in good-to-excellent yields.

  19. Tannic acid Catalyzed an Efficient Synthesis of 2,4,5-Triaryl-1H-Imidazole

    Directory of Open Access Journals (Sweden)

    Shitole Nana Vikram

    2013-05-01

    Full Text Available Tannic acid (C76H52O46 has been found to be an efficient catalyst for one-pot synthesis of 2,4,5-triaryl substituted imidazoles by the reaction of an arylaldehyde, benzyl/benzoin and an ammonium acetate. The short reaction time and excellent yields making this protocol practical and economically attractive.

  20. A convenient procedure for the solid-phase synthesis of hydroxamic acids on PEGA resins

    DEFF Research Database (Denmark)

    Nandurkar, Nitin Subhash; Petersen, Rico; Qvortrup, Katrine;

    2011-01-01

    An efficient method for the solid-phase synthesis of hydroxamic acids is described. The method comprises the nucleophilic displacement of esters immobilized on PEGA resins with hydroxylamine/sodium hydroxide in isopropanol. The hydroxyaminolysis protocol is compatible with a broad range of PEGA...

  1. 2-(hydroxymethyl)aspartic acid: synthesis, crystal structure, and reaction with a transaminase

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.J.; Metzler, D.E.; Powell, D.; Jacobson, R.A.

    1980-11-05

    The synthesis and x-ray crystal structure of 2-(hydroxymethyl) aspartic acid and the preliminary evaluation of its interaction with cytosolic aspartate aminotransferase of pig heart are described. A dissociation constant 1.4 mM for the L-2-(hydroxymethyl) aspartate complex with the enzyme was obtained. 2 figures. (DP)

  2. An Unexpected and Efficient Synthesis of Open-chain Derivatives of Bistetronic Acid under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    SHI Feng; MA Ning; ZHOU Dianxiang; ZHANG Ge; JIANG Bo; TU Shujiang

    2009-01-01

    An unexpected and efficient synthesis of novel open-chain derivatives of bistetronic acid has been successfully achieved in glyclol under microwave irradiation (MW).This method has the prominent advantages of short reaction time,high yield,operational simplicity as well as environmental friendliness.

  3. Mass transfer effects in the H2SO4 catalyzed pivalic acid synthesis

    NARCIS (Netherlands)

    Brilman, D.W.F.; Meesters, N.G.; Swaaij, W.P.M. van; Versteeg, G.F.

    2001-01-01

    The synthesis of carboxylic acids from alkenes, carbon monoxide and water according to the Koch process is usually carried out in a stirred gas–liquid–liquid multiphase reactor. Due to the complex reaction system with fast, equilibrium reactions and fast, irreversible reactions the yield and product

  4. Recent advances in the catalytic asymmetric synthesis of β-amino acids

    NARCIS (Netherlands)

    Weiner, Barbara; Szymanski, Wiktor; Janssen, Dick B.; Minnaard, Adriaan J.; Feringa, Ben L.

    2010-01-01

    In this critical review, the progress in catalytic asymmetric synthesis of β-amino acids is discussed, covering the literature since 2002. The review treats transition metal catalysis, organocatalysis and biocatalysis and covers the most important synthetic methods, such as hydrogenation, the Mannic

  5. Synthesis and pharmacology of 3-hydroxy-delta2-isoxazoline-cyclopentane analogues of glutamic acid

    DEFF Research Database (Denmark)

    Conti, P; De Amici, M; Bräuner-Osborne, Hans;

    2002-01-01

    The synthesis and pharmacology of two potential glutamic acid receptor ligands are described. Preparation of the bicyclic 3-hydroxy-delta2-isoxazoline-cyclopentane derivatives (+/-)-7 and (+/-)-8 was accomplished via 1,3-dipolar cycloaddition of bromonitrile oxide to suitably protected 1-amino...

  6. Synthesis of an ent-Halimanolide from ent-Halimic Acid

    Directory of Open Access Journals (Sweden)

    Julio G. Urones

    2008-05-01

    Full Text Available An efficient synthesis of ent-halimanolide 2 (15,16-epoxy-12-oxo-ent-halima- 5(10,13(16,14-trien-18,2β-olide, from ent-halimic acid has been achieved, corroborating the structure of the natural compound and establishing its absolute configuration.

  7. Phenylboronic acid catalysed synthesis of 1,5-benzodiazepines via cyclocondensation of -phenylenediamine and ketones

    Indian Academy of Sciences (India)

    Santosh V Goswami; Prashant B Thorat; Sudhakar R Bhusare

    2013-07-01

    Phenylboronic acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepine derivatives via cyclocondensation of -phenylenediamine and various ketones in good to excellent yields (82-91%) using acetonitrile as solvent at reflux condition. The remarkable advantages offered by this method are easy mild reaction condition, experimental work up and good to excellent yields of products.

  8. Effect of Whole-Body X-Irradiation of the Synthesis of Individual Fatty Acids in Liver Slices from Normal and Fasted Rats

    DEFF Research Database (Denmark)

    Hansen, Heinz Johs. Max; Hansen, Lisbeth Grænge; Faber, M.

    1965-01-01

    (1) Using (2-14C) acetate and (1-14C) butyrate as precursors, rat-liver fatty acids were synthesized in vitro and assayed by paper chromatography. (2) Whole-body x-irradiation induced a change in the synthetic pattern of hepatic fatty acids towards a relatively enhanced synthesis of palmitic acid....... (3) X-irradiation and fasting seem to have opposite effects on fatty-acid synthesis. X-irradiation counteracts the drop in total synthesis and the relatively enhanced synthesis of palmitoleic acid induced by fasting. The relative enhancement of palmitic-acid synthesis mentioned under (2) stands...

  9. Synthesis and transdermal properties of acetylsalicylic acid and selected esters.

    Science.gov (United States)

    Gerber, Minja; Breytenbach, Jaco C; Hadgraft, Jonathan; du Plessis, Jeanetta

    2006-03-01

    The primary aim of this study was to determine the transdermal penetration of acetylsalicylic acid and some of its derivatives, to establish a correlation, if any, with selected physicochemical properties and to determine if transdermal application of acetylsalicylic acid and its derivatives will give therapeutic drug concentrations with respect to transdermal flux. Ten derivatives of acetylsalicylic acid were prepared by esterification of acetylsalicyloyl chloride with ten different alcohols. The experimental aqueous solubility, logD and transdermal flux values were determined for acetylsalicylic acid and its derivatives at pH 4.5. In vitro penetration was measured through excised female human abdominal skin in diffusion cells. The experimental aqueous solubility of acetylsalicylic acid (6.56 mg/ml) was higher than that of the synthesised acetylsalicylate derivatives (ranging from 1.76 x 10(-3) to 3.32 mg/ml), and the logD of acetylsalicylic acid (-0.85) was lower than that of its derivatives (ranging from -0.25 to 1.95). There was thus an inverse correlation between the aqueous solubility data and the logD values. The experimental transdermal flux of acetylsalicylic acid (263.83 nmol/cm(2)h) was much higher than that of its derivatives (ranging from 0.12 to 136.02 nmol/cm(2)h).

  10. SYNTHESIS AND PHARMACOLOGICAL SCREENING OF NSUBSTITUTED ANTHRANILIC ACID DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Dileep Tiwari

    2011-06-01

    Full Text Available In the present work eight newly synthesized structurally diverse anthranilic acid derivatives were evaluated for their anti-inflammatory activity against carrageenan induced oedema in albino rats. All the anthranilic acid derivatives were compared for their percentage inhibition of the oedema using control drug phenylbutazone. The desired anthranilic acid derivatives 5-bromo-2-{[5-{[(2E-3-(2- substitutedphenylprop-2-enoyl]amino}-1,3,4,-oxadiazol-2- yl methyl]amino}benzoic acid (compounds 1-4 were synthesized by condensation of 5-bromo-N - (2'-amino acetyl -1',3',4'-oxadiazol-5'-ylmethyl anthranilic acid and substituted aromatic aldehydes, respectively, and the compounds 5-bromo-N – [2'-amino [1"-acetyl-5''- (substitutedaryl-2'-pyrazolin-3"-yl]-1'3'4'-oxadiazol-5'- ylmethyl anthranilic acid (compounds 5-8 were synthesized by the condensation of compounds (1-4 with the hydrazine hydrate in the presence of few drops of glacial acetic acid. Compound 5 was found to be a potent member of this series which showed 51.05% antiinflammatory activity with ED50 of 51.05 mg/kg while phenylbutazone exhibited 47.23% anti-inflammatory activity at the same dose. The structures of the newly synthesized compounds have been established on the basis of spectral (FTIR and 1H-NMR data and elemental analysis.

  11. [Asymmetric synthesis of aromatic L-amino acids catalyzed by transaminase].

    Science.gov (United States)

    Xia, Wenna; Sun, Yu; Min, Cong; Han, Wei; Wu, Sheng

    2012-11-01

    Aromatic L-Amino acids are important chiral building blocks for the synthesis of many drugs, pesticides, fine chemicals and food additives. Due to the high activity and steroselectivity, enzymatic synthesis of chiral building blocks has become the main research direction in asymmetric synthesis field. Guided by the phylogenetic analysis of transaminases from different sources, two representative aromatic transaminases TyrB and Aro8 in type I subfamily, from the prokaryote Escherichia coli and eukaryote Saccharomyces cerevisia, respectively, were applied for the comparative study of asymmetric transamination reaction process and catalytic efficiency of reversely converting keto acids to the corresponding aromatic L-amino acid. Both TyrB and Aro8 could efficiently synthesize the natural aromatic amino acids phenylalanine and tyrosine as well as non-natural amino acid phenylglycine. The chiral HPLC analysis showed the produced amino acids were L-configuration and the e.e value was 100%. L-alanine was the optimal amino donor, and the transaminase TyrB and Aro8 could not use D-amino acids as amino donor. The optimal molar ratio of amino donor (L-alanine) and amino acceptor (aromatic alpha-keto acids) was 4:1. Both of the substituted group on the aromatic ring and the length of fatty acid carbon chain part in the molecular structure of aromatic substrate alpha-keto acid have the significant impact on the enzyme-catalyzed transamination efficiency. In the experiments of preparative-scale transamination synthesis of L-phenylglycine, L-phenylalanine and L-tyrosine, the specific production rate catalyzed by TryB were 0.28 g/(g x h), 0.31 g/(g x h) and 0.60 g/(g x h) and the specific production rate catalyzed by Aro8 were 0.61 g/(g x h), 0.48 g/(g x h) and 0.59 g/(g x h). The results obtained here were useful for applying the transaminases to asymmetric synthesis of L-amino acids by reversing the reaction balance in industry.

  12. Synthesis of polyacrylic-acid-based thermochromic polymers

    Science.gov (United States)

    Srivastava, Jyoti; Alam, Sarfaraz; Mathur, G. N.

    2003-10-01

    Smart materials respond to environmental stimuli with particular changes in some variables (for example temperature, pressure and electric field etc), for that reason they are often called responsive materials. In the present work, we have synthesized thermochromic polymer based on poly acrylic acid cobalt chloride (CoCl2) and phosphoric acid (H3PO4) that visually and reversibly changes color in the temperature range (70 - 130°C). These thermochromic materials can be used as visual sensors of temperature. Thermochromic polymers are based on polyacrylic acid and CoCl2 complex.

  13. Retinoic acid synthesis and functions in early embryonic development

    Directory of Open Access Journals (Sweden)

    Kam Richard Kin Ting

    2012-03-01

    Full Text Available Abstract Retinoic acid (RA is a morphogen derived from retinol (vitamin A that plays important roles in cell growth, differentiation, and organogenesis. The production of RA from retinol requires two consecutive enzymatic reactions catalyzed by different sets of dehydrogenases. The retinol is first oxidized into retinal, which is then oxidized into RA. The RA interacts with retinoic acid receptor (RAR and retinoic acid X receptor (RXR which then regulate the target gene expression. In this review, we have discussed the metabolism of RA and the important components of RA signaling pathway, and highlighted current understanding of the functions of RA during early embryonic development.

  14. Polylactic acid (PLA) synthesis and modifications: a review

    Institute of Scientific and Technical Information of China (English)

    Yanling CHENG; Shaobo DENG; Paul CHEN; Roger RUAN

    2009-01-01

    This article reviews various methods of synthesizing polycondensation and ring-opening polymerization and modifying properties of polylactic acid (PLA), which may be used as biomaterials, such as a drug carrier in a drug delivery system, as a cell scaffold and suture in tissue engineering, and as packaging materials in packaging engineering field. Copolymerization of lactide with other monomers or polymers such as malic acid, polyethylene glycol (PEG), polyglycolic acid (PGA), or dextran, as well as blending polylactide with natural derivatives and other methods of modification are discussed. Surface modifications of PLA-type copolymers, such as surface coating,chemical modification, and plasma treatment are described.

  15. Microbiologically produced carboxylic acids used as building blocks in organic synthesis.

    Science.gov (United States)

    Aurich, Andreas; Specht, Robert; Müller, Roland A; Stottmeister, Ulrich; Yovkova, Venelina; Otto, Christina; Holz, Martina; Barth, Gerold; Heretsch, Philipp; Thomas, Franziska A; Sicker, Dieter; Giannis, Athanassios

    2012-01-01

    Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building blocks. Thereby, our biotechnological goal was the development of process fundamentals regarding the variable use of renewable raw materials, the development of a multi purpose bioreactor and application of a pilot plant with standard equipment for organic acid production to minimize the technological effort. Furthermore the development of new product isolation procedures, with the aim of direct product recovery, capture of products or single step operation, was necessary. The application of robust and approved microorganisms, also genetically modified, capable of using a wide range of substrates as well as producing a large spectrum of products, was of special importance. Microbiologically produced acids, like 2-oxo-glutaric acid and 2-oxo-D-gluconic acid, are useful educts for the chemical synthesis of hydrophilic triazines, spiro-connected heterocycles, benzotriazines, and pyranoic amino acids. The chiral intermediate of the tricarboxylic acid cycle, (2R,3S)-isocitric acid, is another promising compound. For the first time our process provides large quantities of enantiopure trimethyl (2R,3S)-isocitrate which was used in subsequent chemical transformations to provide new chiral entities for further usage in total synthesis and pharmaceutical research.Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building

  16. Synthesis and Physicochemial Properties of Three Glutaric Acid Diester

    Directory of Open Access Journals (Sweden)

    Salma Bte Samidin

    2016-01-01

    Full Text Available Abstract Three diesters were prepared through the esterification reaction of diacid (glutaric acid with 3 different straight chain alcohols with para-toluene sulphonic acid (PTSA (4% as a catalyst. The resulting products were confirmed by Fourier Transform Infrared (FTIR and Nuclear Magnetic Resonance (NMR analyses. The oxidative stability, viscosity, flash point and pour point were measured.  Dioctyl glutarate and didecyl glutarate showed a liquid form at room temperature. Glutaric acid diesters produced show high oxidative stability, higher than 187˚C and high temperature pour point. Didodecyl glutarate forms solid at room temperature and shows high flash point of 210˚C and viscosity index VI of 194 respectively. Keywords: Biolubricant, esterification, glutaric acid, alcohol

  17. Synthesis and antitumor activity of derivatives of 23-hydroxybetulinic acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of natural product 23-hydroxybetulinic acid derivatives were prepared. In the preparation of mono-O-benzoyl ester derivative, it was observed that benzoyl group migrated from 3-O- to 23-O-position during the detritylation.

  18. Synthesis of azo derivatives of 4-aminosalicylic acid

    Institute of Scientific and Technical Information of China (English)

    Zheng Bao Zhao; Hui Xia Zheng; Yuan Gui Wei; Jiang Liu

    2007-01-01

    For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively.The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, N-salicyloyl glycine acid to get azo derivatives of 4-ASA.The azo derivatives were hydrolyzed under the alkaline condition to get the target products.All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details.New derivatives of 4-ASA were characterized.The synthetic route was reasonable and feasible.

  19. Synthesis of a New Polyoxometalate Loaded Stearic Acid Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Yong YANG; Lei ZHANG; Wei FAN; Xiao Hong WANG; Bin LI; Jing Fu LIU

    2004-01-01

    The stearic acid nanoparticles loaded polyoxometalate K6[γ-(CpTi)2SiW10O38][(CpTi)2SiW10] have been prepared and structurally characterized by elemental analysis, IR spectra.The particle size was estimated by transition electron microscope and zatesizer instrument. The result showed that the polyoxometalate retained the parent structure after encapsulation by stearic acid nanoparticles.

  20. Synthesis and proton conductibility of ternary germanic heteropoly acids

    Institute of Scientific and Technical Information of China (English)

    SANG Xiaoguang; WU Qingyin

    2004-01-01

    The ternary germanic heteropoly acids H5GeW11VO40·22H2O and H5GeMo11VOd0.24H2O were synthesized for the first time by the stepwise acidification and the stepwise addition of solution of the component elements. The products were characterized by ICP, IR, UV, XRD and TG-DTA. The proton conductibility and the activation energy of proton conduction of the heteropoly acids were investigated.

  1. Vapour phase synthesis of salol over solid acids via transesterification

    Indian Academy of Sciences (India)

    S Z Mohamed Shamshuddin; N Nagaraju

    2010-03-01

    The transesterification of methyl salicylate with phenol has been studied in vapour phase over solid acid catalysts such as ZrO2, MoO3 and SO$^{2-}_{4}$ or Mo(VI) ions modified zirconia. The catalytic materials were prepared and characterized for their total surface acidity, BET surface area and powder XRD patterns. The effect of mole-ratio of the reactants, catalyst bed temperature, catalyst weight, flowrate of reactants, WHSV and time-on-stream on the conversion (%) of phenol and selectivity (%) of salol has been investigated. A good yield (up to 70%) of salol with 90% selectivity was observed when the reactions were carried out at a catalyst bed temperature of 200°C and flow-rate of 10 mL/h in presence of Mo(VI)/ZrO2 as catalyst. The results have been interpreted based on the variation of acidic properties and powder XRD phases of zirconia on incorporation of SO$^{2-}_{4}$ or Mo(VI) ions. The effect of poisoning of acid sites of SO$^{2-}_{4}$ or Mo(VI) ions modified zirconia on total surface acidity, powder XRD phases and catalytic activity was also studied. Possible reaction mechanisms for the formation of salol and diphenyl ether over acid sites are proposed.

  2. Inhibition of Fatty Acid Synthesis Induces Apoptosis of Human Pancreatic Cancer Cells.

    Science.gov (United States)

    Nishi, Koji; Suzuki, Kenta; Sawamoto, Junpei; Tokizawa, Yuma; Iwase, Yumiko; Yumita, Nagahiko; Ikeda, Toshihiko

    2016-09-01

    Cancer cells tend to have a high requirement for lipids, including fatty acids, cholesterol and triglyceride, because of their rapid proliferative rate compared to normal cells. In this study, we investigated the effects of inhibition of lipid synthesis on the proliferation and viability of human pancreatic cancer cells. Of the inhibitors of lipid synthesis that were tested, 5-(tetradecyloxy)-2-furoic acid (TOFA), which is an inhibitor of acetyl-CoA carboxylase, and the fatty acid synthase (FAS) inhibitors cerulenin and irgasan, significantly suppressed the proliferation of MiaPaCa-2 and AsPC-1 cells. Treatment of MiaPaCa-2 cells with these inhibitors significantly increased the number of apoptotic cells. In addition, TOFA increased caspase-3 activity and induced cleavage of poly (ADP-ribose) polymerase in MiaPaCa-2 cells. Moreover, addition of palmitate to MiaPaCa-2 cells treated with TOFA rescued cells from apoptotic cell death. These results suggest that TOFA induces apoptosis via depletion of fatty acids and that, among the various aspects of lipid metabolism, inhibition of fatty acid synthesis may be a notable target for the treatment of human pancreatic cancer cells. PMID:27630308

  3. Synthesis and pharmacological evaluation of cyclodextrin conjugate prodrug of mefenamic acid

    Directory of Open Access Journals (Sweden)

    Dev S

    2007-01-01

    Full Text Available In the present investigation mefenamic acid prodrug of β-cyclodextrins was synthesized. The primary hydroxy group of β-cyclodextrins was used to block the acid group. The synthesis involved a series of protection and deprotection reaction. The ester was evaluated for stability in simulated gastric and intestinal fluid. The hydrolysis of cyclodextrin conjugate in colon is confirmed by the hydrolysis kinetics studies in rat faecal material. The ester was also evaluated for ulcerogenicity. Results of these studies established the primary aim of masking the ulcerogenic potential of free drug, by using 12-fold dose of the normal dose of mefenamic acid and equivalent doses of the ester.

  4. THE ASYMMETRIC SYNTHESIS OF AMINO ACIDS UNDER POLYMER-SUPPORTED PHASE TRANSFER CATALYTIC CONDITION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The optical α-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical α-amino acids. This is a new method for the asymmetric synthesis of α-amino acids. The influences of catalyst,temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.

  5. Asymmetric synthesis of -aminophosphonates: The bio-isosteric analogs of -aminobutyric acid

    Indian Academy of Sciences (India)

    Kalisankar Bera; Dwayaja Nadkarni; Iirishi N N Namboothiri

    2013-05-01

    The properties of aminophosphonates as transition state analogs of amino acids, and as antibacterial, antifungal and antiHIV agents attracted considerable attention in recent years. Although many reviews appeared in the literature covering - and -aminophosphonates, -aminophosphonates did not receive sufficient attention despite the fact that parent -aminophosphonic acid and its derivatives are bio-isosteric analogs of GABA (-amino butyric acid). This review provides a critical summary of the significance of -aminophosphonates and various approaches to their synthesis, with particular emphasis to asymmetric versions.

  6. Effect of O-acetylsalicylic acid on lipid synthesis by guinea pig gastric mucosa in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Spohn, M.; McColl, I.

    1987-01-01

    The aim of this work was to investigate the involvement of lipids as possible components of the gastric mucosal barrier by studying the synthesis and secretion of lipids by the epithelial cell lining of gastric mucosa and the effect of salicylate on these processes. O-Acetylsalicylic acid reversibly reduced in vitro incorporation of (U-/sup 14/C) and of DL-(2-/sup 14/C) mevalonic acid into lipids by isolated epithelial cells and by intact mucosa of guinea pig stomach, indicating reversible inhibition of lipid synthesis by the tissue in the presence of the drug. Inhibition of incorporation of both precursors into total lipids, into their fatty acid components, and into cholesterol is demonstrated. 19 refs.

  7. Direct amidation of amino acid derivatives catalyzed by arylboronic acids : applications in dipeptide synthesis.

    OpenAIRE

    Liu, S.; Yang, Y.; Liu, X.; Ferdousi, F. K.; Batsanov, A.S.; Whiting, A

    2013-01-01

    The direct amidation of amino acid derivatives catalyzed by arylboronic acids has been examined. The reaction was generally slow relative to simple amine-carboxylic acid combinations though proceeded at 65–68 °C generally avoiding racemization. 3,4,5-Trifluorophenylboronic and o-nitrophenylboronic acids were found to be the best catalysts, though for slower dipeptide formations, high catalyst loadings were required and an interesting synergistic catalytic effect between two arylboronic acids ...

  8. Synthesis of Enriched 10B Boric Acid of Nuclear Grade

    Institute of Scientific and Technical Information of China (English)

    张雷; 张卫江; 徐姣; 任新

    2014-01-01

    An economic and effective method of preparing enriched 10B boric acid was established by chemical reac-tion of enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certain conditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factors were investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yield of enriched 10B boric acid could reach 97. 2%and the purity was up to 94. 1%under the following conditions:the tem-perature was 50—60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystal-lization and titration analysis, the purity of the product could reach over 99. 2%from 94.1%.

  9. Catabolism of Branched Chain Amino Acids Supports Respiration but Not Volatile Synthesis in Tomato Fruits

    Institute of Scientific and Technical Information of China (English)

    Andrej Kochevenko; Wagner L.Araújo; Gregory S.Maloney; Denise M.Tieman; Phuc Thi Do; Mark G.Taylor; Harry J.Klee; Alisdair R.Fernie

    2012-01-01

    The branched-chain amino acid transaminases (BCATs) have a crucial role in metabolism of the branched-chain amino acids leucine,isoleucine,and valine.These enzymes catalyze the last step of synthesis and the initial step of degradation of these amino acids.Although the biosynthetic pathways of branched chain amino acids in plants have been extensively investigated and a number of genes have been characterized,their catabolism in plants is not yet completely understood.We previously characterized the branched chain amino acid transaminase gene family in tomato,revealing both the subcellular localization and kinetic properties of the enzymes encoded by six genes.Here,we examined possible functions of the enzymes during fruit development.We further characterized transgenic plants differing in the expression of branched chain amino acid transaminases 1 and 3,evaluating the rates of respiration in fruits deficient in BCAT1 and the levels of volatiles in lines overexpressing either BCAT1 or BCAT3.We quantitatively tested,via precursor and isotope feeding experiments,the importance of the branched chain amino acids and their corresponding keto acids in the formation of fruit volatiles.Our results not only demonstrate for the first time the importance of branched chain amino acids in fruit respiration,but also reveal that keto acids,rather than amino acids,are the likely precursors for the branched chain flavor volatiles.

  10. Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

  11. Five Decades with Polyunsaturated Fatty Acids: Chemical Synthesis, Enzymatic Formation, Lipid Peroxidation and Its Biological Effects

    Science.gov (United States)

    Catalá, Angel

    2013-01-01

    I have been involved in research on polyunsaturated fatty acids since 1964 and this review is intended to cover some of the most important aspects of this work. Polyunsaturated fatty acids have followed me during my whole scientific career and I have published a number of studies concerned with different aspects of them such as chemical synthesis, enzymatic formation, metabolism, transport, physical, chemical, and catalytic properties of a reconstructed desaturase system in liposomes, lipid peroxidation, and their effects. The first project I became involved in was the organic synthesis of [1-14C] eicosa-11,14-dienoic acid, with the aim of demonstrating the participation of that compound as a possible intermediary in the biosynthesis of arachidonic acid “in vivo.” From 1966 to 1982, I was involved in several projects that study the metabolism of polyunsaturated fatty acids. In the eighties, we studied fatty acid binding protein. From 1990 up to now, our laboratory has been interested in the lipid peroxidation of biological membranes from various tissues and different species as well as liposomes prepared with phospholipids rich in PUFAs. We tested the effect of many antioxidants such as alpha tocopherol, vitamin A, melatonin and its structural analogues, and conjugated linoleic acid, among others. PMID:24490074

  12. Synthesis and Quantitative Structure-Property Relationships of Side Chain-Modified Hyodeoxycholic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Antimo Gioiello

    2013-08-01

    Full Text Available Bile acids have emerged as versatile signalling compounds of a complex network of nuclear and membrane receptors regulating various endocrine and paracrine functions. The elucidation of the interconnection between the biological pathways under the bile acid control and manifestations of hepatic and metabolic diseases have extended the scope of this class of steroids for in vivo investigations. In this framework, the design and synthesis of novel biliary derivatives able to modulate a specific receptor requires a deep understanding of both structure-activity and structure-property relationships of bile acids. In this paper, we report the preparation and the critical micellization concentration evaluation of a series of hyodeoxycholic acid derivatives characterized by a diverse side chain length and by the presence of a methyl group at the alpha position with respect to the terminal carboxylic acid moiety. The data collected are instrumental to extend on a quantitative basis, the knowledge of the current structure-property relationships of bile acids and will be fruitful, in combination with models of receptor activity, to design and prioritize the synthesis of novel pharmacokinetically suitable ligands useful in the validation of bile acid-responsive receptors as therapeutic targets.

  13. Synthesis, structure, and biological applications of α-fluorinated β-amino acids and derivatives.

    Science.gov (United States)

    March, Taryn L; Johnston, Martin R; Duggan, Peter J; Gardiner, James

    2012-11-01

    This review gives a broad overview of the state of play with respect to the synthesis, conformational properties, and biological activity of α-fluorinated β-amino acids and derivatives. General methods are described for the preparation of monosubstituted α-fluoro-β-amino acids (Scheme 1). Nucleophilic methods for the introduction of fluorine predominantly involve the reaction of DAST with alcohols derived from α-amino acids, whereas electrophilic sources of fluorine such as NFSI have been used in conjunction with Arndt-Eistert homologation, conjugate addition or organocatalyzed Mannich reactions. α,α-Difluoro-β-amino acids have also been prepared using DAST; however, this area of synthesis is largely dominated by the use of difluorinated Reformatsky reagents to introduce the difluoro ester functionality (Scheme 9). α-Fluoro-β-amino acids and derivatives analyzed by X-ray crystal and NMR solution techniques are found to adopt preferred conformations which are thought to result from stereoelectronic effects associated with F located close to amines, amides, and esters (Figs. 2-6). α-Fluoro amide and β-fluoro ethylamide/amine effects can influence the secondary structure of α-fluoro-β-amino acid-containing derivatives including peptides and peptidomimetics (Figs. 7-9). α-Fluoro-β-amino acids are also components of a diverse range of bioactive anticancer (e.g., 5-fluorouracil), antifungal, and antiinsomnia agents as well as protease inhibitors where such fluorinated analogs have shown increased potency and spectrum of activity.

  14. SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF OXIME ESTERS FROM DIHYDROCUMIC ACID

    Directory of Open Access Journals (Sweden)

    Yanqing Gao,

    2012-07-01

    Full Text Available Dihydrocumic acid was prepared from β-pinene through oxidation and dehydration. Then, ten oxime esters from dihydrocumic acid were synthesized. Reaction conditions of the oxime esters were adjusted and their structures were characterized by IR, 1H-NMR, MS, and elemental analysis. The antibacterial activity of these newly synthesized oxime esters against Gram-negative bacteria and Gram-positive bacteria was also investigated using the inhibition zone method. The preliminary results indicated that seven compounds displayed better antibacterial activity against Gram-negative bacteria compared with bromogeramine, a commercially available antibacterial agent.

  15. Phenazines and natural products; novel synthesis of saphenic acid

    DEFF Research Database (Denmark)

    Petersen, Lars; Jensen, Knud J.; Nielsen, John

    1999-01-01

    The natural product saphenic acid (6-(1-hydroxyethyl)1- phenazinecarboxylic acid) was synthesized from readily accessible starting materials. The desired product was obtained in an overall yield of 22% for four steps with the key steps being formation of a diphenylamine, followed by cyclization u...... under alkaline and reducing conditions. Assignments of 1H NMR spectra were achieved by homo- and heteronuclear 1D and 2D correlations. Double pulsed field gradient spin-echo one-dimensional NOESY proved especially valuable for assignment of aromatic protons....

  16. Phenazines and natural products; Novel synthesis of saphenic acid

    DEFF Research Database (Denmark)

    Petersen, Lars; Jensen, Knud Jørgen; Nielsen, John

    1999-01-01

    The natural product saphenic acid (6-(1-hydroxyethyl)1-phenazinecarboxylic acid) was synthesized from readily accessible starting materials. The desired product was obtained in an overall yield of 22% for four steps with the key steps being formation of a diphenylamine, followed by cyclization un...... under alkaline and reducing conditions. Assignments of H-1 NMR spectra were achieved by homo- and heteronuclear 1D and 2D correlations. Double pulsed field gradient spin-echo one-dimensional NOESY proved especially valuable for assignment of aromatic protons....

  17. Radiation synthesis and characterization of polyacrylic acid hydrogels

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pH-sensitive polyacrylic acid (PAA) hydrogels were synthesized by gamma-ray irradiation at an ambient temperature. The influences of dose, monomer concentration, cross-linking agent content, pH, and ionic strength on the swelling ratio (SR) of the PAA hydrogels were investigated in detail. The results show that the SR of the hydrogel decreases with an increase in the dose, monomer concentration, and cross-linking agent content. In alkaline solution, the SR of the hydrogels is much higher than that in acid solution. Also, the ionic strength can influence the SR of the hydrogels. The more the concentration, the lower the SR.

  18. An improved procedure for the synthesis of DL-[2-[sup 13]C]-glutamic acid

    Energy Technology Data Exchange (ETDEWEB)

    Potrzebowski, M.J.; Stolowich, N.J.; Scott, A.I. (Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry)

    1990-03-01

    A convenient two-step chemical synthesis of DL-[2-[sup 13]C]-glutamic acid from methyl acrylate and diethylacetamidomalonate is described. Synthesis of the Michael adduct (III) was effected in quantitative yield by employing strong amino bases as catalysts. The reactivities of three such catalysts, tetramethyl guanidine (TMG), 1,8-diazobicyclo [5,4,0]-undec-7-ene (1,5-5) (DBU) and 1,5-diazobicyclo [4,3,0] non-5-ene (DBN) were compared by [sup 13]C NMR and all are shown to catalyse the reaction quantitatively, however at markedly different rates. (Author).

  19. Docosahexaenoic acid inhibits melanin synthesis in murine melanoma cells in vitro through increasing tyrosinase degradation

    OpenAIRE

    Balcos, Marie Carmel; Kim, Su Yeon; Jeong, Hyo-Soon; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Park, Kyoung-Chan; Kim, Dong-Seok

    2014-01-01

    Aim: To investigate the effects of docosahexaenoic acid (DHA) on melanin synthesis and related regulatory mechanisms. Methods: B16F10 mouse melanoma cells were exposed to DHA for 3 d, and melanin content and tyrosinase activity were measured. Western blot analysis was used to analyze the protein levels in DHA-mediated signal transduction pathways. Results: DHA (1–25 μmol/L) did not affect the viability of B16F10 cells, but decreased α-MSH-induced melanin synthesis in a concentration-dependent...

  20. Synthesis of dopamine analogue containing benzeneboronic acid group, a target compound for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, T.; Yoshino, K. [Shinshu Univ., Faculty of Science, Matsumoto, Nagano (Japan); Hiratsuka, J. [Kawasaki Medical School, Dept. of Radiation Oncology, Kurashiki, Okayama (Japan); Ichihashi, M. [Kobe Univ. (Japan). School of Medicine

    2000-10-01

    Melanin synthesis is accentuated in the melanoma cells. DOPA is one of the melanin precursors, and has been found to be the substrates for tyrosinase. Since Dopamine has the similar structure to DOPA, we have thought that the Dopamine containing boron atom has a possibility to be incorporated into the melanin synthesis pathway, resulting in both higher {sup 10}B-delivery and long lasting {sup 10}B-accumulation in melanoma. Thus, we tried to synthesize a new amide compound between Dopamine and p-carboxybenzeneboronic acid (PCBA). (author)

  1. Synthesis and Structure Elucidation of Cr(III Complexes of Polydentate Hydroxamic Acid Ligands

    Directory of Open Access Journals (Sweden)

    K.P. SRIVASTAVA

    2013-06-01

    Full Text Available The ligands α-mercaptobenzacetohydroxamic acid (MBAHA-H and 2-amino-α-mercaptobenzacetohydroxamic acid (AMBAHA-H and their different mixed ligand novel complexes with CrIII having specific formulae have been synthesized and characterised by elemental analyses, magnetic and conductance measurements, IR and electronic spectral studies. The ligands were found to behave as monobasic tridentate (SO’O donor and tetradentate (SO’ ON donor manner respectively. All the synthesized CrIII complexes were non-electrolyte with magnetic moment ranging from 3.79 to 3.87 BM. The structural assessment of the complexes has been carried out based on spectral studies (electronic&infrared and molar conductivity values. All the complexes were found to be of octahedral geometry.

  2. Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes.

    Science.gov (United States)

    Kohli, Gurjeet S; John, Uwe; Van Dolah, Frances M; Murray, Shauna A

    2016-08-01

    Fatty acids, which are essential cell membrane constituents and fuel storage molecules, are thought to share a common evolutionary origin with polyketide toxins in eukaryotes. While fatty acids are primary metabolic products, polyketide toxins are secondary metabolites that are involved in ecologically relevant processes, such as chemical defence, and produce the adverse effects of harmful algal blooms. Selection pressures on such compounds may be different, resulting in differing evolutionary histories. Surprisingly, some studies of dinoflagellates have suggested that the same enzymes may catalyse these processes. Here we show the presence and evolutionary distinctiveness of genes encoding six key enzymes essential for fatty acid production in 13 eukaryotic lineages for which no previous sequence data were available (alveolates: dinoflagellates, Vitrella, Chromera; stramenopiles: bolidophytes, chrysophytes, pelagophytes, raphidophytes, dictyochophytes, pinguiophytes, xanthophytes; Rhizaria: chlorarachniophytes, haplosporida; euglenids) and 8 other lineages (apicomplexans, bacillariophytes, synurophytes, cryptophytes, haptophytes, chlorophyceans, prasinophytes, trebouxiophytes). The phylogeny of fatty acid synthase genes reflects the evolutionary history of the organism, indicating selection to maintain conserved functionality. In contrast, polyketide synthase gene families are highly expanded in dinoflagellates and haptophytes, suggesting relaxed constraints in their evolutionary history, while completely absent from some protist lineages. This demonstrates a vast potential for the production of bioactive polyketide compounds in some lineages of microbial eukaryotes, indicating that the evolution of these compounds may have played an important role in their ecological success. PMID:26784357

  3. Synthesis and Antiviral Activity of Hydrogenated Ferulic Acid Derivatives

    OpenAIRE

    Can Cui; Zhi-Peng Wang; Xiu-jiang Du; Li-Zhong Wang; Shu-Jing Yu; Xing-Hai Liu; Zheng-Ming Li; Wei-Guang Zhao

    2013-01-01

    A series of hydrogenated ferulic acid amide derivatives 4 were synthesized. The molecular structures of the synthesized compounds were analyzed by H1 NMR and HRMS. The biological activity study showed that some of them displayed excellent protection activity and curative activity against TMV at 500 μg/mL.

  4. Synthesis of 9-oxononanoic acid, a precursor for biopolymers.

    Science.gov (United States)

    Otte, Konrad B; Kirtz, Marko; Nestl, Bettina M; Hauer, Bernhard

    2013-11-01

    Polymers based on renewable resources have become increasingly important. The natural functionalization of fats and oils enables an easy access to interesting monomeric building blocks, which in turn transform the derivative biopolymers into high-performance materials. Unfortunately, interesting building blocks of medium-chain length are difficult to obtain by traditional chemical means. Herein, a biotechnological pathway is established that could provide an environmentally suitable and sustainable alternative. A multiple enzyme two-step one-pot process efficiently catalyzed by a coupled 9S-lipoxygenase (St-LOX1, Solanum tuberosum) and 9/13-hydroperoxide lyase (Cm-9/13HPL, Cucumis melo) cascade reaction is proposed as a potential route for the conversion of linoleic acid into 9-oxononanoic acid, which is a precursor for biopolymers. Lipoxygenase catalyzes the insertion of oxygen into linoleic acid through a radical mechanism to give 9S-hydroperoxy-octadecadienoic acid (9S-HPODE) as a cascade intermediate, which is subsequently cleaved by the action of Cm-9/13HPL. This one-pot process afforded a yield of 73 % combined with high selectivity. The best reaction performance was achieved when lipoxygenase and hydroperoxide lyase were applied in a successive rather than a simultaneous manner. Green leaf volatiles, which are desired flavor and fragrance products, are formed as by-products in this reaction cascade. Furthermore, we have investigated the enantioselectivity of 9/13-HPLs, which exhibited a strong preference for 9S-HPODE over 9R-HPODE.

  5. Total synthesis of five lipoteichoic acids of Clostridium difficile

    DEFF Research Database (Denmark)

    Hogendorf, Wouter Frederik Johan; Gisch, Nicolas; Schwudke, Dominik;

    2014-01-01

    The emergence of hypervirulent resistant strains have made Clostridium difficile a notorious nosocomial pathogen and has resulted in a renewed interest in preventive strategies, such as vaccines based on (synthetic) cell wall antigens. Recently, the structure of the lipoteichoic acid (LTA...

  6. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    Directory of Open Access Journals (Sweden)

    Sylvain Rault

    2007-11-01

    Full Text Available A feasibility and chemical study of the coupling conditions of L-ascorbic acidwith ferulic acid derivatives are described on the basis of the known synergistic effects ofmixtures of various antioxidants. Novel L-ascorbic ferulic hybrids linked at the C-3hydroxyl group were prepared with the aim to protect the alcohol function and the enediolsystem.

  7. An efficient enzymatic synthesis of 5-aminovaleric acid

    NARCIS (Netherlands)

    Pukin, A.; Boeriu, C.G.; Scott, E.L.; Sanders, J.P.M.; Franssen, M.C.R.

    2010-01-01

    The title compound was prepared enzymatically from l-lysine in an excellent yield and under buffer-free conditions. l-Lysine was oxidized by the action of l-lysine a-oxidase from Trichoderma viride followed by spontaneous oxidative decarboxylation of the intermediate 6-amino-2-oxocaproic acid in the

  8. Synthesis and Fungicidal Activities of Pyrimethanil Heterocyclic Acid Salt

    Institute of Scientific and Technical Information of China (English)

    SUN,Xiao-Hong; LIU,Yuan-Fa; CHEN,Bang; JIA,Ying-Qi; YANG,Jian-Wu

    2007-01-01

    Seven pyrimethanil salts were synthesized by organic base containing nitrogen atom reacting with substituted pyridine acids. They are reported for the first time. Their structures have been confirmed by IR, 1H NMR and elemental analysis. The preliminary toxicity tests indicated that most of them exhibited excellent fungicidal activities.The relationship between the structures and the fungicidal activities of the compounds was discussed.

  9. An Improved Synthesis of Retinoic Acid from β-Ionone

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A convenient and large-scale preparation of rctinoic acid 1 from β-ionone in five steps with 38% overall yield is described. The key steps are the epoxidization of 2 with a new methylated agent and the condensation 4 with tetraethyl methylenediphophonate in one-pot procedure to prepare 6.

  10. Recent Advances in Substrate-Controlled Asymmetric Induction Derived from Chiral Pool α-Amino Acids for Natural Product Synthesis.

    Science.gov (United States)

    Paek, Seung-Mann; Jeong, Myeonggyo; Jo, Jeyun; Heo, Yu Mi; Han, Young Taek; Yun, Hwayoung

    2016-07-21

    Chiral pool α-amino acids have been used as powerful tools for the total synthesis of structurally diverse natural products. Some common naturally occurring α-amino acids are readily available in both enantiomerically pure forms. The applications of the chiral pool in asymmetric synthesis can be categorized prudently as chiral sources, devices, and inducers. This review specifically examines recent advances in substrate-controlled asymmetric reactions induced by the chirality of α-amino acid templates in natural product synthesis research and related areas.

  11. Synthesis of new fatty acids amides from aminolysis of fatty acid methyl esters (FAMEs); Sintese de novas amidas graxas a partir da aminolise de esteres metilicos

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carolina R.; Montes D' Oca, Caroline da Ros; Duarte, Rodrigo da C.; Kurz, Marcia H.S.; Primel, Ednei G.; Clementin, Rosilene M.; Villarreyes, Joaquin Ariel M.; Montes D' Oca, Marcelo G., E-mail: dqmdoca@furg.b [Universidade Federal do Rio Grande, RS (Brazil). Escola de Quimica e Alimentos

    2010-07-01

    Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce cytotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs). (author)

  12. Synthesis and Biological Evaluation of Novel Phosphatidylcholine Analogues Containing Monoterpene Acids as Potent Antiproliferative Agents.

    Directory of Open Access Journals (Sweden)

    Anna Gliszczyńska

    Full Text Available The synthesis of novel phosphatidylcholines with geranic and citronellic acids in sn-1 and sn-2 positions is described. The structured phospholipids were obtained in high yields (59-87% and evaluated in vitro for their cytotoxic activity against several cancer cell lines of different origin: MV4-11, A-549, MCF-7, LOVO, LOVO/DX, HepG2 and also towards non-cancer cell line BALB/3T3 (normal mice fibroblasts. The phosphatidylcholines modified with monoterpene acid showed a significantly higher antiproliferative activity than free monoterpene acids. The highest activity was observed for the terpene-phospholipids containing the isoprenoid acids in sn-1 position of phosphatidylcholine and palmitic acid in sn-2.

  13. Synthesis and Biological Evaluation of Novel Phosphatidylcholine Analogues Containing Monoterpene Acids as Potent Antiproliferative Agents

    Science.gov (United States)

    Gliszczyńska, Anna; Niezgoda, Natalia; Gładkowski, Witold; Czarnecka, Marta; Świtalska, Marta; Wietrzyk, Joanna

    2016-01-01

    The synthesis of novel phosphatidylcholines with geranic and citronellic acids in sn-1 and sn-2 positions is described. The structured phospholipids were obtained in high yields (59–87%) and evaluated in vitro for their cytotoxic activity against several cancer cell lines of different origin: MV4-11, A-549, MCF-7, LOVO, LOVO/DX, HepG2 and also towards non-cancer cell line BALB/3T3 (normal mice fibroblasts). The phosphatidylcholines modified with monoterpene acid showed a significantly higher antiproliferative activity than free monoterpene acids. The highest activity was observed for the terpene-phospholipids containing the isoprenoid acids in sn-1 position of phosphatidylcholine and palmitic acid in sn-2. PMID:27310666

  14. Convergent synthesis of degradable dendrons based on L-malic acid

    DEFF Research Database (Denmark)

    Meyhoff, Ulrich; Riber, Ulla; Boas, Ulrik

    2015-01-01

    New degradable polyester dendrons based on the cellular tricarboxylic acid cycle component L-malic acid were synthesized up to the third generation by convergent synthesis. The dendron wedges could be introduced in a stepwise, highly regioselective fashion. HMBC-NMR revealed that the C1-carbonyl on...... malic acid was exclusively esterified, before the reaction of the second dendron wedge at C4 took place. Degradation studies on a first generation dendron analyzed by HPLC showed that hydrolytic degradation of the dendron most profoundly takes place at pH 4 and pH 9 with the highest degradation rate at...... alkaline pH. NMR shows that the dendron degrades to malic acid and fumaric acid derivatives. Preliminary studies performed in the cell culture show low toxicity of the dendrons in concentrations of up to 50 μg mL-1....

  15. Effect Factors in Synthesis of Nicotinic Acid by Electrooxidation of 3-Picoline

    Institute of Scientific and Technical Information of China (English)

    SUN Xiu-yun; ZHANG Yu-min; CAO Xue-jing; ZHANG Heng-bin; LI Fei; XU Yu-ling

    2005-01-01

    In an electrolytic cell with a proton exchange membrane, nicotinic acid was synthesized at the PbO2 anode. The relationship between the current density and the potential at different concentrations of 3-picoline and sulfuric acid as well as at different temperatures was studied with polarization curves. The effects of the concentrations of sulfuric acid and 3-picoline, the anode potential and the reaction temperature on the selectivity and the current efficiency were explored. The optimum conditions were determined by orthogonal experiments. Under optimum conditions the selectivity and the current efficiency for the synthesis of nicotinic acid might reach 89% and 65%, respectively. The concentrations of 3-picoline and nicotinic acid were analyzed with high performance liquid chromatography and the product was characterized with elemental analysis, chromatography-mass spectrometry and IR spectrometry.

  16. Stereoselective Synthesis of 1-Aminocyclopropanecarboxylic Acid Derivatives via Ylide Cyclopropanation of Dehydroamino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    Zhou Rui; Deng Xianming; Zheng Juncheng; Shen Qi; Sun Xiuli; Tang Yong

    2011-01-01

    1-Aminocyclopropanecarboxylic acid derivatives are synthesized from readily available dehydroamino acid de-rivatives via sulfur ylide. A range of different ylides are employed and the corresponding aminocyclopropanes are afforded with reasonable diastereoselection in good yields.

  17. Synthesis and curing of alkyd enamels based on ricinoleic acid

    Directory of Open Access Journals (Sweden)

    Jovičić Mirjana C.

    2010-01-01

    Full Text Available A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricinoleic acid were formulated by calculation on alkyd constant. Alkyds were characterized by FTIR and by the determination of acid and hydroxyl numbers. Then synthesized alkyds were made into baking enamels by mixing with melamine-formaldehyde resins (weight ratio of 70:30 based on dried mass. Two types of commercial melamine resins were used: threeisobutoxymethyl melamine-formaldehyde resin (TIMMF and hexamethoxymethyl melamine resin (HMMMF. Prepared alkyd/melamine resin mixtures were cured in a differential scanning calorimeter (DSC under non-isothermal mode. Apparent degree of curing as a function of temperature was calculated from the curing enthalpies. Kinetic parameters of curing were calculated using Freeman-Carroll method. TIMMF resin is more reactive with synthesized alkyds than HMMMF resin what was expected. Alkyd resin with 30 wt% of ricinoleic acid is slightly more reactive than alkyd with 40 wt% of ricinoleic acid, probably because it has the high contents of free hydroxyl and acid groups. The gel content, Tg, thermal stability, hardness, elasticity and impact resistance of coated films cured at 150°C for 60 min were measured. Cured films show good thermal stability since the onset of films thermal degradation determined by thermogravimetric analysis (TGA is observed at the temperatures from 281 to 329°C. Films based on alkyd 30 are more thermal stable than those from alkyd 40, with the same melamine resin. The type of alkyd resin has no significant

  18. Role of amidation in bile acid effect on DNA synthesis by regenerating mouse liver.

    Science.gov (United States)

    Barbero, E R; Herrera, M C; Monte, M J; Serrano, M A; Marin, J J

    1995-06-01

    Effect of bile acids on DNA synthesis by the regenerating liver was investigated in mice in vivo after partial hepatectomy (PH). Radioactivity incorporation into DNA after [14C]thymidine intraperitoneal administration peaked at 48 h after PH. At this time a significant taurocholate-induced dose-dependent reduction in DNA synthesis without changes in total liver radioactivity content was found (half-maximal effect at approximately 0.1 mumol/g body wt). Effect of taurocholate (0.5 mumol/g body wt) was mimicked by chocolate, ursodeoxycholate, deoxycholate, dehydrocholate, tauroursodeoxycholate, taurochenodeoxycholate, and taurodeoxycholate. In contrast, chenodeoxycholate, glycocholate, glycochenodeoxycholate, glycoursodeoxycholate, glycodeoxycholate, 5 beta-cholestane, bromosulfophthalein, and free taurine lacked this effect. No relationship between hydrophobic-hydrophilic balance and inhibitory effect was observed. Analysis by high-performance liquid chromatography indicated that inhibition of thymidine incorporation into DNA was not accompanied by an accumulation of phosphorylated DNA precursors in the liver but rather by a parallel increase in nucleotide catabolism. Bile acid-induced modifications in DNA synthesis were observed in vivo even in the absence of changes in toxicity tests, which suggests that the inhibitory effect shared by most unconjugated and tauroconjugated bile acids but not by glycoconjugated bile acids should be accounted for by mechanisms other than nonselective liver cell injury. PMID:7611405

  19. Synthesis and characterization of a pH responsive folic acid functionalized polymeric drug delivery system.

    Science.gov (United States)

    Li, Xia; McTaggart, Matt; Malardier-Jugroot, Cecile

    2016-01-01

    We report the computational analysis, synthesis and characterization of folate functionalized poly(styrene-alt-maleic anhydride), PSMA for drug delivery purpose. The selection of the proper linker between the polymer and the folic acid group was performed before conducting the synthesis using Density Functional Theory (DFT). The computational results showed the bio-degradable linker 2, 4-diaminobutyric acid, DABA as a good candidate allowing flexibility of the folic acid group while maintaining the pH sensitivity of PSMA, used as a trigger for drug release. The synthesis was subsequently carried out in multi-step experimental procedures. The functionalized polymer was characterized using InfraRed spectroscopy, Nuclear Magnetic Resonance and Dynamic Light Scattering confirming both the chemical structure and the pH responsiveness of PSMA-DABA-Folate polymers. This study provides an excellent example of how computational chemistry can be used in selection process for the functional materials and product characterization. The pH sensitive polymers are expected to be used in delivering anti-cancer drugs to solid tumors with overly expressed folic acid receptors. PMID:27183249

  20. Synthesis and Verification of Biobased Terephthalic Acid from Furfural

    Science.gov (United States)

    Tachibana, Yuya; Kimura, Saori; Kasuya, Ken-Ichi

    2015-02-01

    Exploiting biomass as an alternative to petrochemicals for the production of commodity plastics is vitally important if we are to become a more sustainable society. Here, we report a synthetic route for the production of terephthalic acid (TPA), the monomer of the widely used thermoplastic polymer poly(ethylene terephthalate) (PET), from the biomass-derived starting material furfural. Biobased furfural was oxidised and dehydrated to give maleic anhydride, which was further reacted with biobased furan to give its Diels-Alder (DA) adduct. The dehydration of the DA adduct gave phthalic anhydride, which was converted via phthalic acid and dipotassium phthalate to TPA. The biobased carbon content of the TPA was measured by accelerator mass spectroscopy and the TPA was found to be made of 100% biobased carbon.

  1. Enzymatic synthesis and application of fatty acid ascorbyl esters

    OpenAIRE

    Stojanović Marija M.; Carević Milica B.; Mihailović Mladen D.; Knežević-Jugović Zorica D.; Petrović Slobodan D.; Bezbradica Dejan I.

    2013-01-01

    Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully use...

  2. THE SYNTHESIS OF MACROPOROUS CROSSLINKED POLYSTYRENE AMIDOPHOSPHONIC ACID

    Institute of Scientific and Technical Information of China (English)

    HE Binlin; WANG Linfu; CHEN Weizhu

    1984-01-01

    A series of macromolecular copolymers of styrene and divinyl-benzene were prepared in the presence of iso-octanol or 2-ethyl butyl alcohol. The factors which affected the physical structures of the copolymer were discussed. The macroporous amido-phosphonic acid resin was obtained after the acetylation, phosphonylation and amination of the crosslinked polystyrene. The factors which affected each reaction were studied and the change of physical structures of the copolymer were discussed.

  3. Microwave Irradiation Promoted Synthesis of Aryloxy Acetic Acids

    Institute of Scientific and Technical Information of China (English)

    LIN Min; ZHOU Jin-mei; XIA Hai-ping; YANG Rui-feng; LIN Chen

    2004-01-01

    Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%-97.4%) were obtained when the molar ratio of the reactants was n(ArOH) : n(NaOH): n(ClCH2CO2H) =1: 2.5: 1.2 with microwave irradiation power of 640 W for 65-85 s.

  4. Synthesis and photoactivity of phenylazonaphthalene peptide nucleic acid monomers

    Institute of Scientific and Technical Information of China (English)

    Jin Du Li; Miao Chen; Sheng Liu; Hao Bo Zhang; Zhi Lu Liu

    2008-01-01

    Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized,and their photoisomerization was examined.The new PNA monomers showed reversible trans-cis isomerization with UV and visible light irradiation,which might be the foundation of photo-regulating the hybridization between PNA containing phenylazonaphthalene unit and DNA.Simultaneously,the fluorescence of the new PNA monomers might make them especially useful as structural probes.

  5. Electrochemical Dicarboxylation of Styrene: Synthesis of 2-Phenylsuccinic Acid

    Institute of Scientific and Technical Information of China (English)

    WANG, Huan; LIN, Mei-Yu; FANG, Hui-Jue; CHEN, Ting-Ting; LU, Jia-Xing

    2007-01-01

    Electrochemical dicarboxylation of styrene in the presence of atmospheric pressure of CO2 with a Ti cathode monium bromide to give 2-phenylsuccinic acid. Influences of the nature of the electrodes, the current density, the passed charge and the temperature on electrolysis were studied to optimize the electrolytic conditions, with the maximal isolated yield to be 86.07%. The mechanism of the elelctrocarboxylation process has been studied by cyclic voltammetry.

  6. Synthesis and bioactivity of 2',3'-benzoabscisic acid analogs.

    Science.gov (United States)

    Han, Xiaoqiang; Wan, Chuan; Li, Xiuyun; Li, Hong; Yang, Dongyan; Du, Shijie; Xiao, Yumei; Qin, Zhaohai

    2015-06-01

    2',3'-Benzoabscisic acid 4a is significantly more active than (±)-ABA and can be potentially used as a plant growth regulator for agriculture. In this study, six 4a analogs were designed and synthesized. Bioassay showed that 4a displayed greater activity than (±)-ABA and the six analogs produced less inhibition than 4a itself. Specially, some analogs displayed markedly different activities to different physiological and biochemical process, which were largely different from ABA and 4a. Compared to (±)-ABA, 4b and 4c were more effective germination inhibitors for lettuce, but less effective inhibitors for rice elongation. Five-membered analog 5 was higher or slightly weaker in inhibiting Arabidopsis seed germination and rice elongation, respectively, but at least 10 times less effective than (±)-ABA in lettuce seed germination. Dual acid 6 and alkyne acid 20 nearly produced no inhibitory activity for Arabidopsis seed germination, but displayed excellent activity in inhibiting rice seedling growth. The preference of the analogs to different physiology process indicated that they might provide a strategy to develop novel ABA agonists or antagonist and be used as probe to investigate the function of different ABA receptors. PMID:25913114

  7. Increase of uric acid synthesis in irradiated chicken's embryos

    International Nuclear Information System (INIS)

    Several important intermediate and end products of uric acid metabolism as well as their corresponding enzymatic reactions were studied in 16 day-old chicken embryos which had been one or more times irradiated or respectively treated with ammonium chloride. After sublethal X-irradiation and at the time of the second irradiation with 800 R, the activity of the glutamine synthetase and the xanthin dehydrogenase in the kidneys of the embryos was increased. In contrast to this the glutamate dehydrogenase activity was moderately decreased. Two hours after the main irradiation the uric acid values as well as the amount of fixed nitrogen in the blood serum of previously-irradiated embryos are noticeably higher than the comparative data in non-previously irradiated animals. The glutamic acid values increase after the second irradiation, but still remain lower than with the non-previously irradiated animals. I achieved concuring ressults when I treated the embryos with ammonium chloride instead of radiation. (orig./MG)

  8. Inhibitors of Fatty Acid Synthesis Induce PPAR α -Regulated Fatty Acid β -Oxidative Genes: Synergistic Roles of L-FABP and Glucose

    OpenAIRE

    Huan Huang; McIntosh, Avery L.; Martin, Gregory G.; Petrescu, Anca D.; Landrock, Kerstin K.; Danilo Landrock; Kier, Ann B.; Friedhelm Schroeder

    2013-01-01

    While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor-α (PPARα) in the nucleus, was found to bind TOFA and its activated CoA th...

  9. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    Directory of Open Access Journals (Sweden)

    Hartati Hartati

    2013-06-01

    Full Text Available This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively. © 2013 BCREC UNDIP. All rights reservedReceived: 20th January 2013; Revised: 31st March 2013; Accepted: 1st April 2013[How to Cite: Hartati, H., Santoso, M., Triwahyono, S., Prasetyoko, D. (2013. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 14-33. (doi:10.9767/bcrec.8.1.4394.14-33][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4394.14-33] | View in  |

  10. Concise synthesis of the A/BCD-ring fragment of gambieric acid A

    Science.gov (United States)

    Fuwa, Haruhiko; Fukazawa, Ryo; Sasaki, Makoto

    2014-01-01

    Gambieric acid A (GAA) and its congeners belong to the family of marine polycyclic ether natural products. Their highly complex molecular architecture and unique biological activities have been of intense interest within the synthetic community. We have previously reported the first total synthesis, stereochemical reassignment, and preliminary structure–activity relationships of GAA. Here we disclose a concise synthesis of the A/BCD-ring fragment of GAA. The synthesis started from our previously reported synthetic intermediate that represents the A/B-ring. The C-ring was synthesized via an oxiranyl anion coupling and a 6-endo cyclization, and the D-ring was forged by means of an oxidative lactonization and subsequent palladium-catalyzed functionalization of the lactone ring. In this manner, the number of linear synthetic steps required for the construction of the C- and D-rings was reduced from 22 to 11. PMID:25629027

  11. Glutamic Acid - Amino Acid, Neurotransmitter, and Drug - Is Responsible for Protein Synthesis Rhythm in Hepatocyte Populations in vitro and in vivo.

    Science.gov (United States)

    Brodsky, V Y; Malchenko, L A; Konchenko, D S; Zvezdina, N D; Dubovaya, T K

    2016-08-01

    Primary cultures of rat hepatocytes were studied in serum-free media. Ultradian protein synthesis rhythm was used as a marker of cell synchronization in the population. Addition of glutamic acid (0.2 mg/ml) to the medium of nonsynchronous sparse cultures resulted in detection of a common protein synthesis rhythm, hence in synchronization of the cells. The antagonist of glutamic acid metabotropic receptors MCPG (0.01 mg/ml) added together with glutamic acid abolished the synchronization effect; in sparse cultures, no rhythm was detected. Feeding rats with glutamic acid (30 mg with food) resulted in protein synthesis rhythm in sparse cultures obtained from the rats. After feeding without glutamic acid, linear kinetics of protein synthesis was revealed. Thus, glutamic acid, a component of blood as a non-neural transmitter, can synchronize the activity of hepatocytes and can form common rhythm of protein synthesis in vitro and in vivo. This effect is realized via receptors. Mechanisms of cell-cell communication are discussed on analyzing effects of non-neural functions of neurotransmitters. Glutamic acid is used clinically in humans. Hence, a previously unknown function of this drug is revealed. PMID:27677557

  12. Effects of Long Chain Fatty Acid Synthesis and Associated Gene Expression in Microalga Tetraselmis sp.

    Directory of Open Access Journals (Sweden)

    T. Catalina Adarme-Vega

    2014-06-01

    Full Text Available With the depletion of global fish stocks, caused by high demand and effective fishing techniques, alternative sources for long chain omega-3 fatty acids are required for human nutrition and aquaculture feeds. Recent research has focused on land-based cultivation of microalgae, the primary producers of omega-3 fatty acids in the marine food web. The effect of salinity on fatty acids and related gene expression was studied in the model marine microalga, Tetraselmis sp. M8. Correlations were found for specific fatty acid biosynthesis and gene expression according to salinity and the growth phase. Low salinity was found to increase the conversion of C18:4 stearidonic acid (SDA to C20:4 eicosatetraenoic acid (ETA, correlating with increased transcript abundance of the Δ-6-elongase-encoding gene in salinities of 5 and 10 ppt compared to higher salinity levels. The expression of the gene encoding β-ketoacyl-coenzyme was also found to increase at lower salinities during the nutrient deprivation phase (Day 4, but decreased with further nutrient stress. Nutrient deprivation also triggered fatty acids synthesis at all salinities, and C20:5 eicosapentaenoic acid (EPA increased relative to total fatty acids, with nutrient starvation achieving a maximum of 7% EPA at Day 6 at a salinity of 40 ppt.

  13. Overexpression of malate dehydrogenase in transgenic alfalfa enhances organic acid synthesis and confers tolerance to aluminum.

    Science.gov (United States)

    Tesfaye, M; Temple, S J; Allan, D L; Vance, C P; Samac, D A

    2001-12-01

    Al toxicity is a severe impediment to production of many crops in acid soil. Toxicity can be reduced through lime application to raise soil pH, however this amendment does not remedy subsoil acidity, and liming may not always be practical or cost-effective. Addition of organic acids to plant nutrient solutions alleviates phytotoxic Al effects, presumably by chelating Al and rendering it less toxic. In an effort to increase organic acid secretion and thereby enhance Al tolerance in alfalfa (Medicago sativa), we produced transgenic plants using nodule-enhanced forms of malate dehydrogenase and phosphoenolpyruvate carboxylase cDNAs under the control of the constitutive cauliflower mosaic virus 35S promoter. We report that a 1.6-fold increase in malate dehydrogenase enzyme specific activity in root tips of selected transgenic alfalfa led to a 4.2-fold increase in root concentration as well as a 7.1-fold increase in root exudation of citrate, oxalate, malate, succinate, and acetate compared with untransformed control alfalfa plants. Overexpression of phosphoenolpyruvate carboxylase enzyme specific activity in transgenic alfalfa did not result in increased root exudation of organic acids. The degree of Al tolerance by transformed plants in hydroponic solutions and in naturally acid soil corresponded with their patterns of organic acid exudation and supports the concept that enhancing organic acid synthesis in plants may be an effective strategy to cope with soil acidity and Al toxicity. PMID:11743127

  14. Benign synthesis of 2-ethylhexanoic acid by cytochrome P450cam: enzymatic, crystallographic, and theoretical studies.

    Science.gov (United States)

    French, K J; Strickler, M D; Rock, D A; Rock, D A; Bennett, G A; Wahlstrom, J L; Goldstein, B M; Jones, J P

    2001-08-14

    This study examines the ability of P450cam to catalyze the formation of 2-ethylhexanoic acid from 2-ethylhexanol relative to its activity on the natural substrate camphor. As is the case for camphor, the P450cam exhibits stereoselectivity for binding (R)- and (S)-2-ethylhexanol. Kinetic studies indicate (R)-2-ethylhexanoic acid is produced 3.5 times as fast as the (S)-enantiomer. In a racemic mixture of 2-ethylhexanol, P450cam produces 50% more (R)-2-ethylhexanoic acid than (S)-2-ethylhexanoic acid. The reason for stereoselective 2-ethylhexanoic acid production is seen in regioselectivity assays, where (R)-2-ethylhexanoic acid comprises 50% of total products while (S)-2-ethylhexanoic acid comprises only 13%. (R)- and (S)-2-ethylhexanol exhibit similar characteristics with respect to the amount of oxygen and reducing equivalents consumed, however, with (S)-2-ethylhexanol turnover producing more water than the (R)-enantiomer. Crystallographic studies of P450cam with (R)- or (S)-2-ethylhexanoic acid suggest that the (R)-enantiomer binds in a more ordered state. These results indicate that wild-type P450cam displays stereoselectivity toward 2-ethylhexanoic acid synthesis, providing a platform for rational active site design. PMID:11583152

  15. Clean synthesis of biodiesel over solid acid catalysts of sulfonated mesopolymers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    FDU-15-SO3H,a solid acid material prepared from the sulfonation of FDU-15 mesoporous polymer,has been demonstrated to serve as an efficient catalyst in the esterification of palmitic acid with methanol as well as in the transesterification of fatty acid-edible oil mixture.FDU-15-SO3H achieved an acid conversion of 99.0% when the esterification was carried out at 343 K with a methanol/palmitic acid molar ratio of 6:1 and 5 wt% catalyst loading.It was capable of giving 99.0% yield of fatty acid methyl esters (FAME) when the transesterification of soybean oil was performed at 413 K and the methanol/oil weight ratio of 1:1.FDU-15-SO3H was further applied to the transesterification/esterification of the oil mixtures with a varying ratio of soybean oil to palmitic acid,which simulated the feedstock with a high content of free fatty acids.The yield of FAME reached 95% for the oil mixtures containing 30 wt% palmitic acid.This indicated the sulfonated mesopolymer was a potential catalyst for clean synthesis of fuel alternative of biodiesel from the waste oil without further purification.

  16. In situ synthesis of peptide nucleic acids in porous silicon for drug delivery and biosensing.

    Science.gov (United States)

    Beavers, Kelsey R; Mares, Jeremy W; Swartz, Caleb M; Zhao, Yiliang; Weiss, Sharon M; Duvall, Craig L

    2014-07-16

    Peptide nucleic acids (PNA) are a unique class of synthetic molecules that have a peptide backbone and can hybridize with nucleic acids. Here, a versatile method has been developed for the automated, in situ synthesis of PNA from a porous silicon (PSi) substrate for applications in gene therapy and biosensing. Nondestructive optical measurements were performed to monitor single base additions of PNA initiated from (3-aminopropyl)triethoxysilane attached to the surface of PSi films, and mass spectrometry was conducted to verify synthesis of the desired sequence. Comparison of in situ synthesis to postsynthesis surface conjugation of the full PNA molecules showed that surface mediated, in situ PNA synthesis increased loading 8-fold. For therapeutic proof-of-concept, controlled PNA release from PSi films was characterized in phosphate buffered saline, and PSi nanoparticles fabricated from PSi films containing in situ grown PNA complementary to micro-RNA (miR) 122 generated significant anti-miR activity in a Huh7 psiCHECK-miR122 cell line. The applicability of this platform for biosensing was also demonstrated using optical measurements that indicated selective hybridization of complementary DNA target molecules to PNA synthesized in situ on PSi films. These collective data confirm that we have established a novel PNA-PSi platform with broad utility in drug delivery and biosensing.

  17. Rheb-TOR signaling promotes protein synthesis, but not glucose or amino acid import, in Drosophila

    Directory of Open Access Journals (Sweden)

    de la Cruz Aida

    2007-03-01

    Full Text Available Abstract Background The Ras-related GTPase, Rheb, regulates the growth of animal cells. Genetic and biochemical tests place Rheb upstream of the target of rapamycin (TOR protein kinase, and downstream of the tuberous sclerosis complex (TSC1/TSC2 and the insulin-signaling pathway. TOR activity is regulated by nutritional cues, suggesting that Rheb might either control, or respond to, nutrient availability. Results We show that Rheb and TOR do not promote the import of glucose, bulk amino acids, or arginine in Drosophila S2 cells, but that both gene products are important regulators of ribosome biogenesis, protein synthesis, and cell size. S2 cell size, protein synthesis, and glucose import were largely insensitive to manipulations of insulin signaling components, suggesting that cellular energy levels and TOR activity can be maintained through insulin/PI3K-independent mechanisms in S2 cell culture. In vivo in Drosophila larvae, however, we found that insulin signaling can regulate protein synthesis, and thus may affect TOR activity. Conclusion Rheb-TOR signaling controls S2 cell growth by promoting ribosome production and protein synthesis, but apparently not by direct effects on the import of amino acids or glucose. The effect of insulin signaling upon TOR activity varies according to cellular type and context.

  18. Synthesis, binding affinity at glutamic acid receptors, neuroprotective effects, and molecular modeling investigation of novel dihydroisoxazole amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Grazioso, Giovanni;

    2005-01-01

    The four stereoisomers of 5-(2-amino-2-carboxyethyl)-4,5-dihydroisoxazole-3-carboxylic acid(+)-4, (-)-4, (+)-5, and (-)-5 were prepared by stereoselective synthesis of two pairs of enantiomers, which were subsequently resolved by enzymatic procedures. These four stereoisomers and the four stereoi...... derivatives showed high antagonist potency with preference for the NR2A and NR2B subtypes, with derivative (-)-4 behaving as the most potent antagonist. The biological data are discussed on the basis of homology models reported in the literature for NMDA receptors and mGluRs....

  19. Stereoselective Synthesis of α-Amino-C-phosphinic Acids and Derivatives

    Directory of Open Access Journals (Sweden)

    José Luis Viveros-Ceballos

    2016-08-01

    Full Text Available α-Amino-C-phosphinic acids and derivatives are an important group of compounds of synthetic and medicinal interest and particular attention has been dedicated to their stereoselective synthesis in recent years. Among these, phosphinic pseudopeptides have acquired pharmacological importance in influencing physiologic and pathologic processes, primarily acting as inhibitors for proteolytic enzymes where molecular stereochemistry has proven to be critical. This review summarizes the latest developments in the asymmetric synthesis of acyclic and phosphacyclic α-amino-C-phosphinic acids and derivatives, following in the first case an order according to the strategy used, whereas for cyclic compounds the nitrogen embedding in the heterocyclic core is considered. In addition selected examples of pharmacological implications of title compounds are also disclosed.

  20. Efficient Fixation of Carbon Dioxide by Electrolysis - Facile Synthesis of Useful Carboxylic Acids -

    Institute of Scientific and Technical Information of China (English)

    Masao Tokuda

    2006-01-01

    Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide (scCO2) has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.

  1. REGULATION OF CARDIAC AND SKELETAL MUSCLE PROTEIN SYNTHESIS BY INDIVIDUAL BRANCHED-CHAIN AMINO ACIDS IN NEONATAL PIGS

    Science.gov (United States)

    Skeletal muscle grows at a very rapid rate in the neonatal pig, due in part to an enhanced sensitivity of protein synthesis to the postprandial rise in amino acids. An increase in leucine alone stimulates protein synthesis in skeletal muscle of the neonatal pig; however, the effect of isoleucine and...

  2. A practical synthesis of 3,4-diethoxybenzthioamide based on Friedel-Crafts reaction with potassium thiocyanate in methanesulfonic acid.

    Science.gov (United States)

    Aki, Shinji; Fujioka, Takafumi; Ishigami, Masashi; Minamikawa, Jun-ichi

    2002-09-01

    The synthesis of 3,4-diethoxybenzthioamide, the key intermediate for OPC-6535, is achieved by employing Friedel-Crafts reaction of 1,2-diethoxybenzene with potassium thiocyanate in methanesulfonic acid at ambient temperature.

  3. Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory

    2008-10-15

    The synthesis of nano-crystalline activated fly ash catalyst (AFAC) with crystallite size of 12 nm was carried out by chemical and thermal treatment of fly ash, a waste material generated from coal-burning power plants. Fly ash was chemically activated using sulfuric acid followed by thermal activation at 600{sup o}C. The variation of surface and physico-chemical properties of the fly ash by activation methods resulted in improved acidity and therefore, catalytic activity for acid catalyzed reactions. The AFAC was characterized by X-ray diffraction, FT-IR spectroscopy, N{sub 2}-adsorption-desorption isotherm, scanning electron microscopy, flame atomic absorption spectrophotometry and sulfur content by CHNS/O elemental analysis. It showed amorphous nature due to high silica content (81%) and possessed high BET surface area (120 m{sup 2}/g). The catalyst was found to be highly active solid acid catalyst for liquid phase esterification of salicylic acid with acetic anhydride and methanol giving acetylsalicylic acid and methyl salicylate respectively. A maximum yield of 97% with high purity of acetylsalicylic acid (aspirin) and a very high conversion 87% of salicylic acid to methyl salicylate (oil of wintergreen) was obtained with AFAC. The surface acidity and therefore, catalytic activity in AFAC was originated by increased silica content, hydroxyl content and higher surface area as compared to fly ash. The study shows that coal generated fly ash can be converted into potential solid acid catalyst for acid catalyzed reactions. Furthermore, this catalyst may replace conventional environmentally hazardous homogeneous liquid acids making an ecofriendly; solvent free, atom efficient, solid acid based catalytic process. 27 refs., 5 figs., 2 tabs.

  4. Oleic acid coated magnetic nano-particles: Synthesis and characterizations

    International Nuclear Information System (INIS)

    Magnetic nano particles of Fe3O4 coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe2+ and Fe3+ ions. The nano particles were characterized using XRD, TEM, FTIR, TGA and VSM. X-ray diffraction studies showed that nano particles consist of single phase Fe3O4 having inverse spinel structure. The particle size obtained from width of Bragg peak is about 12.6 nm. TEM analysis showed that sizes of nano particles are in range of 6 to 17 nm with a dominant population at 12 - 14 nm. FTIR and TGA analysis showed that -COOH group of oleic acid is bound to the surface of Fe3O4 particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe3O4 particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm

  5. Oleic acid coated magnetic nano-particles: Synthesis and characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Biswajit, E-mail: bpanda@mes.ac.in; Goyal, P. S. [Pillai’s Institute of Information Technology, Engineering, Media Studies and Research, Dr. K. M. Vasudevan Pillai’s Campus, New Panvel, 410 206 (India)

    2015-06-24

    Magnetic nano particles of Fe{sub 3}O{sub 4} coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe{sup 2+} and Fe{sup 3+} ions. The nano particles were characterized using XRD, TEM, FTIR, TGA and VSM. X-ray diffraction studies showed that nano particles consist of single phase Fe{sub 3}O{sub 4} having inverse spinel structure. The particle size obtained from width of Bragg peak is about 12.6 nm. TEM analysis showed that sizes of nano particles are in range of 6 to 17 nm with a dominant population at 12 - 14 nm. FTIR and TGA analysis showed that -COOH group of oleic acid is bound to the surface of Fe{sub 3}O{sub 4} particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe{sub 3}O{sub 4} particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm.

  6. Synthesis and Characterization of Polyamides Based on Dimer Acid

    Institute of Scientific and Technical Information of China (English)

    WANG Wenzhi; ZHANG Zhifang; XU Meiyun; ZHANG Yonghua

    2009-01-01

    A series of dimer acid-based polyamides were synthesized by melt-polycondensation of dimer acid and various aromatic diamines,and were characterized by Fourier transform infrared spectrum(FT-IR)and nuclear magnetic resonance(1~H NMR).The physical properties of the polyamides,such as glass transition temperature,melting temperature,decomposition temperature and mechanical properties were also investigated.The polyamides'intrinsic viscosity ranges from 1.8 dL·g~(-1) to 2.2 dL·g~(-1),and the melting temperature ranges from 140℃to 181℃.The glass transition temperatures,observed from dynamic mechanical analysis,fall in the range of 34.8-48.2℃.The physical and mechanical properties of the resultant polyamides are similar to those of the PA1212.The heat resistance and mechanical properties of poly(4,4'-diphenylsulfone dimeramide)(PSD)and poly(4,4'-diphenyl dimeramide)(PPDI)are comparable to those of PA1212.

  7. Enzymatic synthesis of enantiopure alpha- and beta-amino acids by phenylalanine aminomutase-catalysed amination of cinnamic acid derivatives.

    Science.gov (United States)

    Wu, Bian; Szymanski, Wiktor; Wietzes, Piet; de Wildeman, Stefaan; Poelarends, Gerrit J; Feringa, Ben L; Janssen, Dick B

    2009-01-26

    The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of alpha-phenylalanine to beta-phenylalanine, an important step in the biosynthesis of the N-benzoyl phenylisoserinoyl side-chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)-cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring-substituted (E)-cinnamic acids can serve as a substrate in PAM-catalysed ammonia addition reactions for the biocatalytic production of several important beta-amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non-natural aromatic alpha- and beta-amino acids in excellent enantiomeric excess (ee >99 %). The internal 5-methylene-3,5-dihydroimidazol-4-one (MIO) cofactor is essential for the PAM-catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent.

  8. Synthesis of labelled compound of ferulic acid and caffeic acid with tritium

    International Nuclear Information System (INIS)

    Effective components of Chinese traditional herbs consist of many compounds, but some of the compounds usually contain unsaturated carbon-carbon double bonds. The unsaturated organic compounds 3H-Ferulic acid and 3H-Caffeic acid are prepared with their tritiated intermediates made by electric-dischange exposure method, which ensures the compounds contaning double bonds not hydrogenated. The 3H-Ferulic acid is composed of 3H-vanillin and Malonic acid. The 3H-Caffeic acid is composed of 3H-protocatechuyl aldehyde and Malonic acid and the specific activity of the products is 0.2 mCi/mg. The radiochemicaly purity is greater than 90%

  9. Exercise, Amino Acids and Aging in the Control of Human Muscle Protein Synthesis

    OpenAIRE

    Walker, Dillon K.; Dickinson, Jared M.; Timmerman, Kyle L.; Drummond, Micah J.; Reidy, Paul T.; Fry, Christopher S.; Gundermann, David M.; Rasmussen, Blake B.

    2011-01-01

    In this review we discuss recent research in the field of human skeletal muscle protein metabolism characterizing the acute regulation of mammalian target of rapamycin complex (mTORC) 1 signaling and muscle protein synthesis (MPS) by exercise, amino acid nutrition and aging. Resistance exercise performed in the fasted state stimulates mixed MPS within 1 h post-exercise, which can remain elevated for 48 h. We demonstrate that the activation of mTORC1 signaling (and subsequently enhanced transl...

  10. o-Iodoxybenzoic acid mediated oxidative desulfurization initiated domino reactions for synthesis of azoles.

    Science.gov (United States)

    Chaudhari, Pramod S; Pathare, Sagar P; Akamanchi, Krishnacharaya G

    2012-04-20

    A systematic exploration of thiophilic ability of o-iodoxybenzoic acid (IBX) for oxidative desulfurization to trigger domino reactions leading to new methodologies for synthesis of different azoles is described. A variety of highly substituted oxadiazoles, thiadiazoles, triazoles, and tetrazoles have been successfully synthesized in good to excellent yields, starting from readily accessible thiosemicarbazides, bis-diarylthiourea, 1,3-disubtituted thiourea, and thioamides. PMID:22423599

  11. Synthesis and activity of 2-oxoamides containing long chain beta-amino acids.

    Science.gov (United States)

    Constantinou-Kokotou, Violetta; Peristeraki, Anna; Kokotos, Christoforos G; Six, David A; Dennis, Edward A

    2005-07-01

    2-Oxoamides based on long chain beta-amino acids were synthesized. 1-Benzyl substituted long chain amines, needed for such synthesis, were synthesized starting from Boc-phenylalaninol. The oxidative conversion of a phenyl group to a carboxyl group was used as the key transformation synthetic step. The compounds synthesized were studied for their activity against GIVA PLA(2), and were proven to be weak inhibitors. PMID:15635664

  12. Recent Advances in the Total Synthesis of Tetramic Acid-Containing Natural Products

    OpenAIRE

    Wen-Ju Bai; Chen Lu; Xiqing Wang

    2016-01-01

    With incredible bioactivities and fascinating structural complexities, tetramic acid- (TA-) containing natural products have attracted favorable attention among the organic chemistry community. Although the construction of the TA core is usually straightforward, the intricate C3-side chain sometimes asks for some deliberative strategy so as to fulfill an elegant total synthesis. This review mainly covers some exceptional synthetic examples for each type of natural product in recent years, sho...

  13. Synthesis and Application of Phenyl Nitrone Derivatives as Acidic and Microbial Corrosion Inhibitors

    OpenAIRE

    Shijun Chen; Kang Zhao; Gang Chen

    2015-01-01

    Nitrone has drawn great attention due to its wide applications as a 1,3-dipole in heterocyclic compounds synthesis and the bioactivities. With the special structure, nitrone can also be used as ligand in inorganic chemistry. Based on the current research, the nitrones are anticipated to be effective inhibitors against acidic and microbial corrosion. The aim of this work is to investigate the inhibitory action of nitrones. In this work, a series of phenyl nitrone derivatives (PN) was synthesiz...

  14. Enzymatic Synthesis of Dipeptide Derivatives Containing Noncoded Amino Acids in Organic Solvents

    Institute of Scientific and Technical Information of China (English)

    YANG,Hong(杨洪); ZHOU,Chuang(周闯); TIAN,Gui-Ling(田桂玲); YE,Yun-Hua(叶蕴华)

    2002-01-01

    A series of dipeptide derivatives containing non-coded amino acis, N-Boc-4-X-Phe-Ala-NHNHNHPh (X= Cl, Br, I, NO2),were synthesized by using thermoase in organic solvents. The physical data were consistent with the same samples prepared by 3-( diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4 (3H)-one (DEPBT). Influence of different substituted groups of the non-coded amino acids and different organic solvents on the enzymatic peptide synthesis was studied.

  15. Synthesis and characterization of covalent diphenylalanine nanotube-folic acid conjugates

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Rindzevicius, Tomas; Wu, Kaiyu;

    2014-01-01

    Herein, we describe the synthesis and characterization of a covalent nanoscale assembly formed between diphenylalanine micro/nanotubes (PNT) and folic acid (FA). The conjugate was obtained via chemical functionalization through coupling of amine groups of PNTs and carboxylic groups of FA. The sur...... for applications in the detection and diagnosis of cancer or tropical diseases such as leishmaniasis and as a carrier nanosystem delivering drugs to malignant tumors that overexpress folate receptors....

  16. Polyanionic Carboxyethyl Peptide Nucleic Acids (ce-PNAs: Synthesis and DNA Binding.

    Directory of Open Access Journals (Sweden)

    Yuliya Kirillova

    Full Text Available New polyanionic modifications of polyamide nucleic acid mimics were obtained. Thymine decamers were synthesized from respective chiral α- and γ-monomers, and their enantiomeric purity was assessed. Here, we present the decamer synthesis, purification and characterization by MALDI-TOF mass spectrometry and an investigation of the hybridization properties of the decamers. We show that the modified γ-S-carboxyethyl-T10 PNA forms a stable triplex with polyadenine DNA.

  17. Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells.

    Science.gov (United States)

    Yagi, A; Machii, K; Nishimura, H; Shida, T; Nishioka, I

    1985-05-15

    A homogeneous glycoprotein (mol. wt 40,000) containing 34% carbohydrate was isolated from Aloe arborescens var. natalensis. At a concentration of 5 micrograms/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed. PMID:3996544

  18. NOVEL 3-ACETYLCOUMARIN SCHIFF’S BASE SYNTHESIS FROM DIFFERENT ACID HYDRAZIDE

    Directory of Open Access Journals (Sweden)

    Anees Pangal

    2013-10-01

    Full Text Available A new series of Schiff’s bases, SB1, SB2 and SB3 were synthesized from 3-acetylcoumarin and different acid hydrazides. The 3-acetyl coumarin was synthesized starting from salicylaldehyde and ethylacetoacetate. The structures of the synthesized compounds have been established on the basis of physical and spectral data. They shows a prominent absorption of -(C=N- in FTIR. A survey of existing literature revealed that there are no reports describing the synthesis of such hydrazones.

  19. Aqueous citric acid as green reaction media for the synthesis of octahydroxanthenes

    Directory of Open Access Journals (Sweden)

    Camilo A. Navarro D.

    2013-08-01

    Full Text Available A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

  20. Abolished synthesis of cholic acid reduces atherosclerotic development in apolipoprotein E knockout mice[S

    OpenAIRE

    Slätis, Katharina; Gåfvels, Mats; Kannisto, Kristina; Ovchinnikova, Olga; Paulsson-Berne, Gabrielle; Parini, Paolo; Jiang, Zhao-Yan; Eggertsen, Gösta

    2010-01-01

    To investigate the effects of abolished cholic acid (CA) synthesis in the ApoE knockout model [apolipoprotein E (apoE) KO],a double-knockout (DKO) mouse model was created by crossbreeding Cyp8b1 knockout mice (Cyp8b1 KO), unable to synthesize the primary bile acid CA, with apoE KO mice. After 5 months of cholesterol feeding, the development of atherosclerotic plaques in the proximal aorta was 50% less in the DKO mice compared with the apoE KO mice. This effect was associated with reduced inte...

  1. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    Directory of Open Access Journals (Sweden)

    Patrick Rabe

    2014-08-01

    Full Text Available Tropodithietic acid (TDA is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus aureus and Vibrio anguillarum for a structure–activity relationship (SAR study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues is presented and the bioactivity of the synthetic compounds is discussed.

  2. Total synthesis of leopolic acid A, a natural 2,3-pyrrolidinedione with antimicrobial activity

    Science.gov (United States)

    Dhavan, Atul A; Kaduskar, Rahul D; Musso, Loana; Scaglioni, Leonardo; Martino, Piera Anna

    2016-01-01

    Summary The first total synthesis of leopolic acid A, a fungal metabolite with a rare 2,3-pyrrolidinedione nucleus linked to an ureido dipeptide, was designed and carried out. Crucial steps for the strategy include a Dieckmann cyclization to obtain the 2,3-pyrrolidinedione ring and a Wittig olefination to install the polymethylene chain. An oxazolidinone-containing leopolic acid A analogue was also synthesized. The antibacterial activity showed by both compounds suggests that they could be considered as promising candidates for future developments. PMID:27559415

  3. Concise and Straightforward Asymmetric Synthesis of a Cyclic Natural Hydroxy-Amino Acid

    Directory of Open Access Journals (Sweden)

    Mario J. Simirgiotis

    2014-11-01

    Full Text Available An enantioselective total synthesis of the natural amino acid (2S,4R,5R-4,5-di-hydroxy-pipecolic acid starting from D-glucoheptono-1, 4-lactone is presented. The best sequence employed as a key step the intramolecular nucleophilic displacement by an amino function of a 6-O-p-toluene-sulphonyl derivative of a methyl D-arabino-hexonate and involved only 12 steps with an overall yield of 19%. The structures of the compounds synthesized were elucidated on the basis of comprehensive spectroscopic (NMR and MS and computational analysis.

  4. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    DEFF Research Database (Denmark)

    Rabe, Patrick; Klapschinski, Tim A.; Brock, Nelson L.;

    2014-01-01

    Tropodithietic acid (TDA) is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus...... aureus and Vibrio anguillarum for a structure-activity relationship (SAR) study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues...

  5. Integrated process of distillation with side reactors for synthesis of organic acid esters

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Chandrakant B; Prindle, John C; Kolah, Aspri; Miller, Dennis J; Lira, Carl T

    2015-11-04

    An integrated process and system for synthesis of organic-acid esters is provided. The method of synthesizing combines reaction and distillation where an organic acid and alcohol composition are passed through a distillation chamber having a plurality of zones. Side reactors are used for drawing off portions of the composition and then recycling them to the distillation column for further purification. Water is removed from a pre-reactor prior to insertion into the distillation column. An integrated heat integration system is contained within the distillation column for further purification and optimizing efficiency in the obtaining of the final product.

  6. Synthesis, characterization, and crystal structure of 2-iodo-3,4,5-trimethoxybenzoic acid

    Science.gov (United States)

    Kolev, Iliyan N.; Petrova, Svetlana P.; Nikolova, Rositsa P.; Dimowa, Louiza T.; Shivachev, Boris L.

    2013-02-01

    This work describes the synthesis of 2-iodo-3,4,5-trimethoxybenzoic acid. The combination of iodine and silver trifluoroacetate (AgTFA) reagents was used successfully for the iodination of 3,4,5-trimetoxybenzoic acid. To improve the efficiency of the synthetic process a significant modification on the experimental design was also performed. The main structural features of the obtained aryl iodide were investigated by a single crystal X-ray diffraction analysis, FTIR, 1H and 13C NMR spectroscopy.

  7. Total synthesis of leopolic acid A, a natural 2,3-pyrrolidinedione with antimicrobial activity

    Science.gov (United States)

    Dhavan, Atul A; Kaduskar, Rahul D; Musso, Loana; Scaglioni, Leonardo; Martino, Piera Anna

    2016-01-01

    Summary The first total synthesis of leopolic acid A, a fungal metabolite with a rare 2,3-pyrrolidinedione nucleus linked to an ureido dipeptide, was designed and carried out. Crucial steps for the strategy include a Dieckmann cyclization to obtain the 2,3-pyrrolidinedione ring and a Wittig olefination to install the polymethylene chain. An oxazolidinone-containing leopolic acid A analogue was also synthesized. The antibacterial activity showed by both compounds suggests that they could be considered as promising candidates for future developments.

  8. Synthesis of flavanones using methane sulphonic acid as a green catalyst and comparision under different conditions

    Directory of Open Access Journals (Sweden)

    R. B. Kshatriya

    2014-06-01

    Full Text Available Flavonoids are an important class of natural products with wide range activities.Flavonoids includes flavone,flavanone,flavane & flavanol.The synthetic route invovles synthesis of chalcone followed by ring closing to give flavanone.So many catalysts were mentioned in past literature.But most efficient catalyst is methane sulphonic acid.It is easy to handle,less reaction time &easily available.Flavanones were synthesized from chalcone using methane sulphonic acid under thermal condition,microw wave and ultrasound condition.Flavanones are syntheisized in very less time compared to other conditions.

  9. IMMOBILIZATION OF Saccharomyces Cerevisiae USING POLY(ACRYLAMIDE) GEL FOR ASYMMETRIC SYNTHESIS OF R(-)-MANDELIC ACID

    Institute of Scientific and Technical Information of China (English)

    LI Zhongqin; GUO Daiping; HUANG Xinghua; YANG Kai; XU Xiaoping

    2006-01-01

    In this paper, the poly(acrylamide) hydrogel used to immobilize saccharomyces cerevisiae for asymmetric synthesis of R(-)-mandelic acid was prepared with free radical ploymerization in deionized water at room temperature under nitrogen atmosphere. The influence of the composition of hydrogel, loading amount of cells and culture conditions on the asymmetric synthesis was investigated. Results show that PAAm hydrogel is a feasible carrier for immobilization of cells which is a potential alternative method to prepare enantiomerically pure R(-)-mandelic acid.

  10. A Novel and Highly Regioselective Synthesis of New Carbamoylcarboxylic Acids from Dianhydrides

    Directory of Open Access Journals (Sweden)

    Adrián Ochoa-Terán

    2014-01-01

    Full Text Available A regioselective synthesis has been developed for the preparation of a series of N,N′-disubstituted 4,4′-carbonylbis(carbamoylbenzoic acids and N,N′-disubstituted bis(carbamoyl terephthalic acids by treatment of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (1 and 1,2,4,5-benzenetetracarboxylic dianhydride (2 with arylalkyl primary amines (A-N. The carbamoylcarboxylic acid derivatives were synthesized with good yield and high purity. The specific reaction conditions were established to obtain carbamoyl and carboxylic acid functionalities over the thermodynamically most favored imide group. Products derived from both anhydrides 1 and 2 were isolated as pure regioisomeric compounds under innovative experimental conditions. The chemo- and regioselectivity of products derived from dianhydrides were determined by NMR spectroscopy and confirmed by density functional theory (DFT. All products were characterized by NMR, FTIR, and MS.

  11. Photocatalytic Synthesis of Gold Nanoparticles Using Preyssler Acid and Their Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    Ali AYATI; Ali AHMADPOUR; Fatemeh F. BAMOHARRAM; Majid M. HERAVI; Hamed RASHIDI

    2011-01-01

    Preyssler acid H14[NaP5W30O110] was used as reducing agent and stabilizer for the synthesis of gold nanoparticles by photolysis of Au(Ⅲ)/Preyssler acid/propan-2-ol solution. Preyssler acid plays both the role of transferring electrons from propan-2-ol to Au(Ⅲ) and stabilizing the nanoparticles. Propan-2-ol was used as sacrificial reagent for the photoformation of reduced Preyssler acid. Gold nanoparticles (Au NPs) were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM), and particle size distribution (PSD) measurements. The synthesized Au NPs had a uniform hexagonal morphology and their size was about 17 nm. The catalytic performance of these NPs for photodegradation of methyl orange (MeO) was investigated in aqueous solution. UV-Vis studies showed that Au NPs can catalyze photodegradation of this azo dye. The pseudo-first-order rate constants were also calculated for this reaction.

  12. Ionic liquids as novel solvents for the synthesis of sugar fatty acid ester.

    Science.gov (United States)

    Mai, Ngoc Lan; Ahn, Kihun; Bae, Sang Woo; Shin, Dong Woo; Morya, Vivek Kumar; Koo, Yoon-Mo

    2014-12-01

    Sugar fatty acid esters are bio-surfactants known for their non-toxic, non-ionic, and high biodegradability . With great emulsifying and conditioning effects, sugar fatty acids are widely used in the food, pharmaceutical, and cosmetic industries. Biosynthesis of sugar fatty acid esters has attracted growing attention in recent decades. In this study, the enzymatic synthesis of sugar fatty acid esters in ionic liquids was developed, optimized, and scaled up. Reaction parameters affecting the conversion yield of lipase-catalyzed synthesis of glucose laurate from glucose and vinyl laurate (i.e. temperature, vinyl laurate/glucose molar ratio, and enzyme loads) were optimized by response surface methodology (RSM). In addition, production was scaled up to 2.5 L, and recycling of enzyme and ionic liquids was investigated. The results showed that under optimal reaction conditions (66.86 °C, vinyl laurate/glucose molar ratio of 7.63, enzyme load of 73.33 g/L), an experimental conversion yield of 96.4% was obtained which is close to the optimal value predicted by RSM (97.16%). A similar conversion yield was maintained when the reaction was carried out at 2.5 L. Moreover, the enzymes and ionic liquids could be recycled and reused effectively for up to 10 cycles. The results indicate the feasibility of ionic liquids as novel solvents for the biosynthesis of sugar fatty acid esters.

  13. Quantitative Proteomics: Measuring Protein Synthesis Using 15N Amino Acids Labeling in Pancreas Cancer Cells

    Science.gov (United States)

    Zhao, Yingchun; Lee, Wai-Nang Paul; Lim, Shu; Go, Vay Liang; Xiao, Jing; Cao, Rui; Zhang, Hengwei; Recker, Robert; Xiao, Gary Guishan

    2010-01-01

    Pancreatic cancer MIA PaCa cells were cultured in the presence and absence of 15N amino acids mixture for 72 hours. During protein synthesis, the incorporation of 15N amino acids results in a new mass isotopomer distribution in protein, which is approximated by the concatenation of two binomial distributions of 13C and 15N. Fraction of protein synthesis (FSR) can thus be determined from the relative intensities of the ‘labeled’ (new) and the ‘unlabeled” (old) spectra. Six prominent spots were picked from 2-D gels of proteins from lysates of cells cultured in 0% (control), and 50% and 33% 15N enriched media. These protein spots were digested and analyzed with MALDI-TOF/TOF. The isotopomer distribution of peptides after labeling can be fully accounted for by the labeled (new) and unlabeled (old) peptides. The ratio of the new and old peptide fractions was determined using multiple regression analysis of the observed spectrum as a linear combination of the expected new and the old spectra. The fractional protein synthesis rates calculated from such ratios of same peptide from cells grown in 50% and 33% 15N amino acid enrichments were comparable to each other. The FSR of these six identified proteins ranged between 44–76%. PMID:19072287

  14. Metabolic switch during adipogenesis: From branched chain amino acid catabolism to lipid synthesis.

    Science.gov (United States)

    Halama, Anna; Horsch, Marion; Kastenmüller, Gabriele; Möller, Gabriele; Kumar, Pankaj; Prehn, Cornelia; Laumen, Helmut; Hauner, Hans; Hrabĕ de Angelis, Martin; Beckers, Johannes; Suhre, Karsten; Adamski, Jerzy

    2016-01-01

    Fat cell metabolism has an impact on body homeostasis and its proper function. Nevertheless, the knowledge about simultaneous metabolic processes, which occur during adipogenesis and in mature adipocytes, is limited. Identification of key metabolic events associated with fat cell metabolism could be beneficial in the field of novel drug development, drug repurposing, as well as for the discovery of patterns predicting obesity risk. The main objective of our work was to provide comprehensive characterization of metabolic processes occurring during adipogenesis and in mature adipocytes. In order to globally determine crucial metabolic pathways involved in fat cell metabolism, metabolomics and transcriptomics approaches were applied. We observed significantly regulated metabolites correlating with significantly regulated genes at different stages of adipogenesis. We identified the synthesis of phosphatidylcholines, the metabolism of even and odd chain fatty acids, as well as the catabolism of branched chain amino acids (BCAA; leucine, isoleucine and valine) as key regulated pathways. Our further analysis led to identification of an enzymatic switch comprising the enzymes Hmgcs2 (3-hydroxy-3-methylglutaryl-CoA synthase) and Auh (AU RNA binding protein/enoyl-CoA hydratase) which connects leucine degradation with cholesterol synthesis. In addition, propionyl-CoA, a product of isoleucine degradation, was identified as a putative substrate for odd chain fatty acid synthesis. The uncovered crosstalks between BCAA and lipid metabolism during adipogenesis might contribute to the understanding of molecular mechanisms of obesity and have potential implications in obesity prediction. PMID:26408941

  15. Synthesis and characterization of agricultural controllable humic acid superabsorbent.

    Science.gov (United States)

    Gao, Lijuan; Wang, Shiqiang; Zhao, Xuefei

    2013-12-01

    Humic acid superabsorbent polymer (P(AA/AM-HA)) and superabsorbent polymer (P(AA/AM)) were synthesized by aqueous solution polymerization method using acrylic acid (AA), acrylamide (AM) and humic acid (HA) as raw material. The effects of N,N'-methylenebisacrylamide (MBA) crosslinking agent, potassium peroxydisulfate (KPS) initiator, reaction temperature, HA content, ratio of AA to AM, concentration of monomer and neutralization of AA on water absorption were investigated. Absorption and desorption ratios of nitrogen fertilizer and phosphate fertilizer were also investigated by determination of absorption and desorption ratio of NH4(+), PO4(3-) on P(AA/AM-HA) and P(AA/AM). The P(AA/AM-HA) and P(AA/AM) were characterized by Fourier translation infrared spectroscopy, biological photomicroscope and scanning electron microscopy (SEM). The optimal conditions obtained were as follows: the weight ratio of MBA to AA and AM was 0.003; the weight ratio of KPS to AA and AM was 0.008; the weight ratio of HA to AA was 0.1; the mole ratio of AM to AA is 0.1; the mole ratio of NaOH to AA is 0.9; the reaction temperature was 60°C. P(AA/AM-HA) synthesized under optimal conditions, has a good saline tolerance, its water absorbency in distilled water and 0.9 wt.% saline solution is 1180 g/g and 110 g/g, respectively. P(AA/AM-HA) achieves half saturation in 6.5 min. P(AA/AM-HA) is superior to P(AA/AM) on absorption of NH4(+), PO4(3-). The SEM micrograph of P(AA/AM-HA) shows a fine alveolate structure. The biological optical microscope micrograph of P(AA/AM-HA) shows a network structure. Graft polymerization between P(AA/AM) and HA was demonstrated by infrared spectrum. The P(AA/AM-HA) superabsorbent has better absorbing ability of water and fertilizer, electrolytic tolerance and fewer cost than P(AA/AM) superabsorbent. PMID:25078843

  16. Synthesis and Application of a Novel Perfluorooctylated Citric Acid

    Institute of Scientific and Technical Information of China (English)

    YANG Wei; QING Feng-Ling; MENG Wei-Dong

    2005-01-01

    A novel perfluorooctylated citric acid was synthesized successfully via allylation of triethyl citrate followed by perfluorooctylation, reduction and hydrolysis. The fabrics treated with this compound showed good oil repellent and moderate water repellent properties: the oil repellent rating and the water repellent score were 6 and 80 respectively.Even after 10 washing cycles, the repellent properties were kept at the same level. The finished fabrics also showed some wrinkle-resistant properties, and the dry wrinkle recovery angle was increased by 53° compared with untreated fabrics. The critical surface energy of the treated fabric surface was 20±1 mN/m. This multifunctional compound also showed good water solubility, which would be beneficial for the environmental protection.

  17. Synthesis and Insecticidal Activities of Novel Phthalic Acid Diamides

    Institute of Scientific and Technical Information of China (English)

    闫涛; 李玉新; 李永强; 王多义; 陈伟; 刘卓; 李正名

    2012-01-01

    In order to discover novel insecticides with the new action mode on ryanodine receptor (RyR), a series of novel phthalic acid diamide derivatives were designed and synthesized. All compounds were characterized by 1H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that some title compounds exhibited excellent insecticidal activities against Mythimna separata, Spodoptera exigua, and Plutella xylostella. The title compound 3-nitro-N-cyclopropyl-N'-[2-methyl-4-(perfluoropropan-2-yl)phenyl]phthalamidte (4a) was more efficient against diamondback moths than the control (chlorantraniliprole). The effects of some title compounds on intracellular calcium of neurons from the Spodoptera exigua proved that the title compounds were RyR activators.

  18. Synthesis of tyrosine derivatives containing boric acid moiety

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, M.; Yoshino, Kazuo [Shinshu Univ., Faculty of Science, Matsumoto, Nagano (Japan); Kimura, M.

    1998-12-01

    While p-boronophenylalanine (p-BPA) is known as a useful pharmaceutical for Boron Neutron Capture Therapy (BNCT), it is also reported that the boron content after it is accumulated in melanomas decreases gradually with time. 2-hydroxy-5-(2' carboxy-2'-aminoethyl) phenyl boric acid (HBPA) is suggested for alternative candidate to be used, as the compound (HBPA) resembles more in chemical nature to tyrosine and is more difficult to be oxidized by tyrosinase than p-BPA. The authors tried to synthesize HBPA via isocyanoethylacetate, employing 1-bromo-2-methoxy-5-methylbenzene as a starting material. The structure of the synthesized compounds at each steps in the course of the scheme was determined using {sup 1}H, {sup 13}C and {sup 11}B NMR spectrometer. (S. Ohno)

  19. Loss of Nuclear Receptor SHP Impairs but Does Not Eliminate Negative Feedback Regulation of Bile Acid Synthesis

    OpenAIRE

    Kerr, Thomas A.; Saeki, Shigeru; Schneider, Manfred; Schaefer, Karen; Berdy, Sara; Redder, Thadd; Shan, Bei; Russell, David W.; Schwarz, Margrit

    2002-01-01

    The in vivo role of the nuclear receptor SHP in feedback regulation of bile acid synthesis was examined. Loss of SHP in mice caused abnormal accumulation and increased synthesis of bile acids due to derepression of rate-limiting CYP7A1 and CYP8B1 hydroxylase enzymes in the biosynthetic pathway. Dietary bile acids induced liver damage and restored feedback regulation. A synthetic agonist of the nuclear receptor FXR was not hepatotoxic and had no regulatory effects. Reduction of the bile acid p...

  20. Sequential enzymatic synthesis and separation of 13N-L-glutamic acid and 13N-L-alanine

    International Nuclear Information System (INIS)

    The sequential enzymatic synthesis and separation of 13N-L-glutamic acid and 13N-L-alanine are described. Basically, that involves the synthesis of 13N-L-glutamic acid by one enzyme, the transamination of the labeled glutamic acid to form 13N-L-alanine by a second enzyme, and the separation of the two amino acids by rapid column chromatography. The 13N-L-alanine was evaluated in animals by imaging and tissue distribution studies and showed good potential as a pancreatic imaging agent

  1. Synthesis of acid-base bifunctional mesoporous materials by oxidation and thermolysis

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zou, Yongcun [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China); Wu, Shujie; Liu, Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

    2011-06-15

    Graphical abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst. The obtained sample of SO{sub 3}H-MCM-41-NH{sub 2} containing amine and sulfonic acids exhibits excellent catalytic activity in aldol condensation reaction. Research highlights: {yields} Synthesize acid-base bifunctional mesoporous materials SO{sub 3}H-MCM-41-NH{sub 2}. {yields} Oxidation and then thermolysis to generate acidic site and basic site. {yields} Exhibit good catalytic performance in aldol condensation reaction between acetone and various aldehydes. -- Abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst SO{sub 3}H-MCM-41-NH{sub 2}. This method was achieved by co-condensation of tetraethylorthosilicate (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and (3-triethoxysilylpropyl) carbamicacid-1-methylcyclohexylester (3TAME) in the presence of cetyltrimethylammonium bromide (CTAB), followed by oxidation and then thermolysis to generate acidic site and basic site. X-ray diffraction (XRD) and transmission electron micrographs (TEM) show that the resultant materials keep mesoporous structure. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), back titration, solid-state {sup 13}C CP/MAS NMR and solid-state {sup 29}Si MAS NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The bifunctional sample (SO{sub 3}H-MCM-41-NH{sub 2}) containing amine and sulfonic acids exhibits excellent acid-basic properties, which make it possess high activity in aldol condensation reaction between acetone and various aldehydes.

  2. The effect of pantothenic acid deficiency on keratinocyte proliferation and the synthesis of keratinocyte growth factor and collagen in fibroblasts.

    Science.gov (United States)

    Kobayashi, Daisaku; Kusama, Miho; Onda, Masaaki; Nakahata, Norimichi

    2011-01-01

    It has been reported that pantothenic acid (vitamin B5) and panthenol, an alcohol derivative of pantothenic acid, have beneficial moisturizing effects on the skin. However, few studies have investigated the mechanism of action of pantothenic acid on skin tissues. We tried to clarify the role of pantothenic acid on skin function by using keratinocytes and fibroblasts. The depletion of pantothenic acid from the culture medium suppressed keratinocyte proliferation and promoted differentiation. Moreover, pantothenic acid depletion decreased the synthesis of keratinocyte growth factor and procollagen 4a2 in fibroblasts. These results suggest that pantothenic acid is essential for maintaining keratinocyte proliferation and differentiation. PMID:21258175

  3. D-amino acids indirectly inhibit biofilm formation in Bacillus subtilis by interfering with protein synthesis.

    Science.gov (United States)

    Leiman, Sara A; May, Janine M; Lebar, Matthew D; Kahne, Daniel; Kolter, Roberto; Losick, Richard

    2013-12-01

    The soil bacterium Bacillus subtilis forms biofilms on surfaces and at air-liquid interfaces. It was previously reported that these biofilms disassemble late in their life cycle and that conditioned medium from late-stage biofilms inhibits biofilm formation. Such medium contained a mixture of D-leucine, D-methionine, D-tryptophan, and D-tyrosine and was reported to inhibit biofilm formation via the incorporation of these D-amino acids into the cell wall. Here, we show that L-amino acids were able to specifically reverse the inhibitory effects of their cognate D-amino acids. We also show that D-amino acids inhibited growth and the expression of biofilm matrix genes at concentrations that inhibit biofilm formation. Finally, we report that the strain routinely used to study biofilm formation has a mutation in the gene (dtd) encoding D-tyrosyl-tRNA deacylase, an enzyme that prevents the misincorporation of D-amino acids into protein in B. subtilis. When we repaired the dtd gene, B. subtilis became resistant to the biofilm-inhibitory effects of D-amino acids without losing the ability to incorporate at least one noncanonical D-amino acid, D-tryptophan, into the peptidoglycan peptide side chain. We conclude that the susceptibility of B. subtilis to the biofilm-inhibitory effects of D-amino acids is largely, if not entirely, due to their toxic effects on protein synthesis. PMID:24097941

  4. Expanding the amino acid repertoire of ribosomal polypeptide synthesis via the artificial division of codon boxes

    Science.gov (United States)

    Iwane, Yoshihiko; Hitomi, Azusa; Murakami, Hiroshi; Katoh, Takayuki; Goto, Yuki; Suga, Hiroaki

    2016-04-01

    In ribosomal polypeptide synthesis the library of amino acid building blocks is limited by the manner in which codons are used. Of the proteinogenic amino acids, 18 are coded for by multiple codons and therefore many of the 61 sense codons can be considered redundant. Here we report a method to reduce the redundancy of codons by artificially dividing codon boxes to create vacant codons that can then be reassigned to non-proteinogenic amino acids and thereby expand the library of genetically encoded amino acids. To achieve this, we reconstituted a cell-free translation system with 32 in vitro transcripts of transfer RNASNN (tRNASNN) (S = G or C), assigning the initiator and 20 elongator amino acids. Reassignment of three redundant codons was achieved by replacing redundant tRNASNNs with tRNASNNs pre-charged with non-proteinogenic amino acids. As a demonstration, we expressed a 32-mer linear peptide that consists of 20 proteinogenic and three non-proteinogenic amino acids, and a 14-mer macrocyclic peptide that contains more than four non-proteinogenic amino acids.

  5. Fatty Acid Composition of Tobacco Seed Oil and Synthesis of Alkyd Resin

    Institute of Scientific and Technical Information of China (English)

    MUKHTAR,Azam; ULLAH,Habib; MUKHTAR,Hamid

    2007-01-01

    The fatty acid composition of tobacco seed oil revealed that the oil is rich in unsaturated fatty acids, having linoleic acid (71.63%), oleic acid (13.46%) and palmitic acid (8.72%) as the most abundant unsaturated and saturated fatty acids respectively. So the tobacco oil was characterized as semi-drying type on the basis of fatty acid composition. The synthesis of alkyd resin was carried out by alcoholysis or monoglyceride process using an alkali refined tobacco seed oil, pentaerythritol, cis-1,2,3,6-tetrahydrophthalic anhydride along with lithium hydroxide as catalyst.The alkyd resin so prepared was found to be bright and of low color with high gloss. The drying and hardness properties and adhesion of the tobacco seed oil derived alkyd resin were also found a bit superior to those of other alkyd resins of the same oil length. In addition, the water and acid resistance of the said alkyd was also found comparable to the other alkyds.

  6. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B;

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4-isoxa...

  7. Synthesis and Spectroscopic Characterisation of 2,3-Epoxy/3-Chloro-2-hydroxy Propyl Derivatives of Quaternary Ammonium Salts: Useful Cationic Fixing Agents

    Institute of Scientific and Technical Information of China (English)

    SHARIF Saima; AHMAD Saeed; IZHAR-UL-HAQ Mian Muhammad

    2008-01-01

    Eight mono-reactive and four bis-reactive 2,3-epoxy/3-chloro-2-hydroxy propyl derivatives of quaternary ammonium salts have been synthesised by reacting epichlorohydrin with suitable tertiary amines and diamines.Mono-reactive derivatives also contain cyano and carboxylic groups in addition to 2,3-epoxy/3-chloro-2-hydroxy propyl groups. The structures of these quaternary ammonium salts have been characterised using IR and 1H NMR spectroscopic techniques. These quaternary ammonium chlorides have been applied to the cotton fabrics as pretreatments and aftertreatments and promising results have been obtained.

  8. Synthesis, growth of organic nonlinear optical crystal: Semicarbazone of 2-amino-5-chloro-benzophenone (S2A5CB) and its characterisation

    Science.gov (United States)

    Sethuraman, K.; Ramesh Babu, R.; Vijayan, N.; Gopalakrishnan, R.; Ramasamy, P.

    2006-05-01

    A new organic crystal of semicarbazone of 2-amino-5-chloro-benzophenone has been grown as a single crystal by slow evaporation solution growth technique for the first time in the literature. The grown crystal has been characterised by proton nuclear magnetic resonance spectral analysis and single crystal and powder X-ray diffraction studies. Functional groups of the crystallised molecules were confirmed by FT-IR and FT-Raman analyses. Mechanical strength of the crystals was studied by microhardness test. Optical transparency of the grown crystals has been studied by UV-Visible spectra. The second harmonic generation property of the compound was analysed.

  9. Synthesis and characterisation of molybdenum (V) and (VI) complexes of 2,6-diformyl-p-cresol-bis[4-(X-phenyl) thiosemicarbazone

    International Nuclear Information System (INIS)

    Molybdenum (V) and (VI) complexes of novel ligand 2, 6-diformyl-p-cresol bis [4-(X-phenyl) thiosemicarbazone] (where X = -H, o-CH3, m-CH3, p-CH3, p-OCH3 and p-Cl) are synthesised and characterised on the basis of elemental analyses and magnetic, IR, UV, EPR, and NMR spectral studies. The complexes have the composition [MoO2LH] and [MoOClLH]. The Schiff bases behave as dibasic tetradentate SNON donor ligands. (author)

  10. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  11. Synthesis and characterization of arsenate antimonic acid AAAc(1 : 1)

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-wen; CHEN Qi-yuan; YIN Zhou-lan; ZHANG Ping-min; WANG Yu-wen

    2005-01-01

    The AAAc(1 : 1) was synthesized in water by As2O3 and Sb2O3 with molar ratio of 1 : 1: AAAc(1 : 1)was characterized by Raman, IR, TG/DTG, DSC, XPS and XRD. The results show that there are four peaks to vsof As-OH, As-O-Sb, Sb-OH and Sb-O-Sb in Raman spectra of AAAc(1 : 1) at 100 - 1 000 cm-1. The solution of AAAc(1 : 1) was also titrated with KOH solution. The titration results show that AAAc(1 : 1) is a hexabasic acid with dissociation constants of k1 = 3.62 × 10-2 , k2 = 3.05 × 10-3 , k3 = 6. 43 × 10-6 , k4 = 9. 78 × 10-8 ,k5 = 1.32 × 10-11 , k6 =3.87 × 10-12. AAAc(1 : 1) has a good solubility and stability in water, its solid obtained by free volatilizing water from its solution under air at ambient temperature is amorphous. Chemical and thermal analyture of AsO ( OH )2-OH-Sb ( OH )4-O-Sb ( OH )4-OH-AsO ( OH )2 or As ( OH )3-O-Sb(OH)4-O-Sb(OH)4-O-As(OH)3 (isomerism) through experimental determination and geometry optimization.

  12. Whole-body DHA synthesis-secretion kinetics from plasma eicosapentaenoic acid and alpha-linolenic acid in the free-living rat.

    Science.gov (United States)

    Metherel, Adam H; Domenichiello, Anthony F; Kitson, Alex P; Hopperton, Kathryn E; Bazinet, Richard P

    2016-09-01

    Whole body docosahexaenoic acid (DHA, 22:6n-3) synthesis from α-linolenic acid (ALA, 18:3n-3) is considered to be very low, however, the daily synthesis-secretion of DHA may be sufficient to supply the adult brain. The current study aims to assess whether whole body DHA synthesis-secretion kinetics are different when comparing plasma ALA versus eicosapentaenoic acid (EPA, 20:5n-3) as the precursor. Male Long Evans rats (n=6) were fed a 2% ALA in total fat diet for eight weeks, followed by surgery to implant a catheter into each of the jugular vein and carotid artery and 3h of steady-state infusion with a known amount of (2)H-ALA and (13)C-eicosapentaenoic acid (EPA, 20:5n3). Blood samples were collected at thirty-minute intervals and plasma enrichment of (2)H- and (13)C EPA, n-3 docosapentaenoic acid (DPAn-3, 22:5n-3) and DHA were determined for assessment of synthesis-secretion kinetic parameters. Results indicate a 13-fold higher synthesis-secretion coefficient for DHA from EPA as compared to ALA. However, after correcting for the 6.6 fold higher endogenous plasma ALA concentration, no significant differences in daily synthesis-secretion (nmol/day) of DHA (97.6±28.2 and 172±62), DPAn-3 (853±279 and 1139±484) or EPA (1587±592 and 1628±366) were observed from plasma unesterified ALA and EPA sources, respectively. These results suggest that typical diets which are significantly higher in ALA compared to EPA yield similar daily DHA synthesis-secretion despite a significantly higher synthesis-secretion coefficient from EPA. PMID:27263420

  13. Involvement of a universal amino acid synthesis impediment in cytoplasmic male sterility in pepper.

    Science.gov (United States)

    Fang, Xianping; Fu, Hong-Fei; Gong, Zhen-Hui; Chai, Wei-Guo

    2016-01-01

    To explore the mechanisms of pepper (Capsicum annuum L.) cytoplasmic male sterility (CMS), we studied the different maturation processes of sterile and fertile pepper anthers. A paraffin section analysis of the sterile anthers indicated an abnormality of the tapetal layer and an over-vacuolization of the cells. The quantitative proteomics results showed that the expression of histidinol dehydrogenase (HDH), dihydroxy-acid dehydratase (DAD), aspartate aminotransferase (ATAAT), cysteine synthase (CS), delta-1-pyrroline-5-carboxylate synthase (P5CS), and glutamate synthetase (GS) in the amino acid synthesis pathway decreased by more than 1.5-fold. Furthermore, the mRNA and protein expression levels of DAD, ATAAT, CS and P5CS showed a 2- to 16-fold increase in the maintainer line anthers. We also found that most of the amino acid content levels decreased to varying degrees during the anther tapetum period of the sterile line, whereas these levels increased in the maintainer line. The results of our study indicate that during pepper anther development, changes in amino acid synthesis are significant and accompany abnormal tapetum maturity, which is most likely an important cause of male sterility in pepper. PMID:26987793

  14. Downregulation of de Novo Fatty Acid Synthesis in Subcutaneous Adipose Tissue of Moderately Obese Women

    Directory of Open Access Journals (Sweden)

    Esther Guiu-Jurado

    2015-12-01

    Full Text Available The purpose of this work was to evaluate the expression of fatty acid metabolism-related genes in human adipose tissue from moderately obese women. We used qRT-PCR and Western Blot to analyze visceral (VAT and subcutaneous (SAT adipose tissue mRNA expression involved in de novo fatty acid synthesis (ACC1, FAS, fatty acid oxidation (PPARα, PPARδ and inflammation (IL6, TNFα, in normal weight control women (BMI < 25 kg/m2, n = 35 and moderately obese women (BMI 30–38 kg/m2, n = 55. In SAT, ACC1, FAS and PPARα mRNA expression were significantly decreased in moderately obese women compared to controls. The downregulation reported in SAT was more pronounced when BMI increased. In VAT, lipogenic-related genes and PPARα were similar in both groups. Only PPARδ gene expression was significantly increased in moderately obese women. As far as inflammation is concerned, TNFα and IL6 were significantly increased in moderate obesity in both tissues. Our results indicate that there is a progressive downregulation in lipogenesis in SAT as BMI increases, which suggests that SAT decreases the synthesis of fatty acid de novo during the development of obesity, whereas in VAT lipogenesis remains active regardless of the degree of obesity.

  15. Steroselective synthesis and application of L-( sup 15 N) amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J. (Los Alamos National Lab., NM (United States)); Lodwig, S.N. (Centralia Coll., WA (United States). Div. of Science)

    1991-01-01

    We have developed two general approaches to the stereoselective synthesis of {sup 15}N- and {sup 13}C-labeled amino acids. First, labeled serine, biosynthesized using the methylotrophic bacterium M. extorquens AM1, serves as a chiral precursor for the synthesis of other amino acids. For example, pyridoxal phosphate enzymes can be used for the conversion of L-({alpha}-{sup 15}N)serine to L-({alpha}-{sup 15}N)tyrosine, L-({alpha}-{sup 15}N)tryptophan, and L-({alpha}-{sup 15}N)cysteine. In the second approach, developed by Oppolzer and Tamura, an electrophilic amination'' reagent, 1-chloro-1-nitrosocyclohexane, was used to convert chiral enolates into L-{alpha}-amino acids. We prepared 1-chloro-1-({sup 15}N) nitrosocyclohexane and used it to aminate chiral enolates to produce L-({alpha}-{sup 15}N)amino acids. The stereoselectivity of this scheme using the Oppolzer sultam chiral auxiliary is remarkable, producing enantiomer ratios of 200 to 1. 22 refs., 4 figs.

  16. Effect of Nitric Acid Concentrations on Synthesis and Stability of Maghemite Nanoparticles Suspension

    Directory of Open Access Journals (Sweden)

    Irwan Nurdin

    2014-01-01

    Full Text Available Maghemite (γ-Fe2O3 nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD, transmission electron microscopy (TEM, alternating gradient magnetometry (AGM, thermogravimetric analysis (TGA, dynamic light scattering (DLS, and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.

  17. Sulfanilic acid functionalized mesoporous SBA-15: A water-tolerant solid acid catalyst for the synthesis of uracil fused spirooxindoles as antioxidant agents

    Indian Academy of Sciences (India)

    Robabeh Baharfar; Razieh Azimi

    2015-08-01

    Incorporating sulfanilic acid as a hydrophobic Brønsted acid inside the nanospaces of SBA-15 led to a water-tolerant solid acid catalyst, SBA-15-PhSO 3 H, which showed excellent catalytic performance in synthesis of uracil-fused spirooxindoles in aqueous ethanol. The synthesized compounds were evaluated for their antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay.

  18. Azide- and Alkyne-Functionalised α- and β3-Amino Acids

    DEFF Research Database (Denmark)

    Sminia, T.J.; Pedersen, Daniel Sejer

    2012-01-01

    The synthesis and full characterisation of bifunctional β -amino acids that have side chains functionalised with terminal azides (S)-4 and (R)-4 or acetylenes 5 and 6 is reported for the first time. The building blocks incorporate a turn-inducing β -segment and a side chain that can be functional......The synthesis and full characterisation of bifunctional β -amino acids that have side chains functionalised with terminal azides (S)-4 and (R)-4 or acetylenes 5 and 6 is reported for the first time. The building blocks incorporate a turn-inducing β -segment and a side chain that can...... be functionalised further, for example, through copper-catalysed Huisgen cycloaddition. Moreover, the corresponding α-amino acids 1 and 3 have been synthesised and characterised. All amino acid building blocks were of high optical purity as demonstrated by derivatisation and subsequent NMR analysis. © Georg Thieme...

  19. An Efficient Synthesis of 1-Alkyl-2-phenyl-4-quinolones from 2-Halobenzoic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yoon Ju; Choi, Jin Sun; Lee, Jae In [Duksung Women' s Univ., Seoul (Korea, Republic of)

    2013-10-15

    The present method offers an efficient synthesis of 1-alkyl-2-phenyl-4-quinolones from 2-haloben-zoic acids. It has the advantages with respect to (i) synthesis of 2 equiv of alkynones 5 from 1 equiv of 4,6-pyrimidyl di(2-halobenzoates) 3, (ii) synthesis of versatile 1-alkyl-2-phenyl-4-quinolones in high overall yields, and (iii) use of readily available and cheap starting materials. Therefore, this method could be utilized as a practical synthesis of 1-alkyl-2-phenyl-4-quinolones. Several methods have been developed to synthesize 1-alkyl-2-phenyl-4-quinolones from 2'-substituted acetophenones, anilines, and 2-halobenzoyl chlorides as starting materials. The reaction of N-methylisatoic anhydride with the lithium enolate of an 4'-methoxyacetophenone afforded the 1-methyl-2-phenyl-4-quinolone in a short sequence, but the yield was low. N-(2-Acetylphenyl)benzamides, prepared by Friedel-Crafts acylation of N-phenyl benzamides with acetyl chloride or benzoylation of 2'-aminoacetophenones with benzoyl chlorides,8 were cyclized with potassium t-butoxide to yield 2-aryl-4-quinolones, which were further alkylated with alkyl iodides to give 1-alkyl-2-aryl-4-quinolones.

  20. Synthesis and role of salicylic acid in wheat varieties with different levels of cadmium tolerance.

    Science.gov (United States)

    Kovács, Viktória; Gondor, Orsolya K; Szalai, Gabriella; Darkó, Eva; Majláth, Imre; Janda, Tibor; Pál, Magda

    2014-09-15

    Wheat genotypes with different endogenous SA contents were investigated, in order to reveal how cadmium influences salicylic acid (SA) synthesis, and to find possible relationships between SA and certain protective compounds (members of the antioxidants and the heavy metal detoxification system) and between the SA content and the level of cadmium tolerance. Cadmium exposure induced SA synthesis, especially in the leaves, and it is suggested that the phenyl-propanoid synthesis pathway is responsible for the accumulation of SA observed after cadmium stress. Cadmium influenced the synthesis and activation of protective compounds to varying extents in wheat genotypes with different levels of tolerance; the roots and leaves also responded differently to cadmium stress. Although a direct relationship was not found between the initial SA levels and the degree of cadmium tolerance, the results suggest that the increase in the root SA level during cadmium stress in the Mv varieties could be related with the enhancement of the internal glutathione cycle, thus inducing the antioxidant and metal detoxification systems, which promote Cd stress tolerance in wheat seedlings. The positive correlation between certain SA-related compounds and protective compounds suggests that SA-related signalling may also play a role in the acclimation to heavy metal stress.