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Sample records for alanine-l

  1. High-temperature Raman study of L-alanine, L-threonine and taurine crystals related to thermal decomposition

    Science.gov (United States)

    Cavaignac, A. L. O.; Lima, R. J. C.; Façanha Filho, P. F.; Moreno, A. J. D.; Freire, P. T. C.

    2016-03-01

    In this work high-temperature Raman spectra are used to compare temperature dependence of the lattice mode wavenumber of L-alanine, L-threonine and taurine crystals. Anharmonic effects observed are associated with intermolecular N-H· · ·O hydrogen bond that plays an important role in thermal decomposition process of these materials. Short and strong hydrogen bonds in L-alanine crystal were associated with anharmonic effects in lattice modes leading to low thermal stability compared to taurine crystals. Connection between thermal decomposition process and anharmonic effects is furnished for the first time.

  2. Viscosity studies of (L-alanine-, L-proline, L-valine, L-leucine + aqueous KCl/KNO3) solutions at different temperatures

    International Nuclear Information System (INIS)

    Viscosity coefficients of (L-alanine-, L-proline, L-valine, L-leucine + 2.0 M aqueous KCl/KNO3) solutions have been determined as a function of amino acid concentration at different temperatures: (298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K. The trends of variation of viscosity values with increase in the concentration of L-alanine, L-proline, L-valine, and L-leucine in 2.0 M aqueous KCl and 2.0 M aqueous KNO3 solutions, and temperature have been ascribed to the solute-solvent interactions operative in the solutions

  3. Effective production of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) with Erwinia herbicola cells carrying a mutant transcriptional regulator TyrR.

    Science.gov (United States)

    Koyanagi, Takashi; Katayama, Takane; Suzuki, Hideyuki; Nakazawa, Hidetsugu; Yokozeki, Kenzo; Kumagai, Hidehiko

    2005-02-01

    The enzymatic production of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) using Erwinia herbicola cells involves the action of tyrosine phenol-lyase (Tpl, EC 4.1.99.2). Since Tpl is only synthesized under L-tyrosine-induced conditions, the addition of L-tyrosine to the medium is unavoidable when preparing cells (the enzyme source), but severely impedes the pure preparation of the final product L-DOPA. We circumvented this problem by using recombinant E. herbicola cells carrying a mutant transcriptional regulator TyrR, which is capable of activating the tpl promoter in the absence of L-tyrosine. PMID:15639092

  4. Hyperproduction of 3,4-dihydroxyphenyl-L-alanine (L-Dopa) using Erwinia herbicola cells carrying a mutant transcriptional regulator TyrR.

    Science.gov (United States)

    Koyanagi, Takashi; Katayama, Takane; Suzuki, Hideyuki; Onishi, Akiko; Yokozeki, Kenzo; Kumagai, Hidehiko

    2009-05-01

    In the last few decades, enzymatic production of 3,4-dihydroxyphenyl-L-alanine (L-dopa) using tyrosine phenol-lyase (Tpl) has been industrialized. This method has an intrinsic problem of tyrosine contamination because Tpl is synthesized under tyrosine-induced conditions. Herein, we constructed a hyper-L-dopa-producing strain by exploiting a mutant TyrR, an activator of tpl. The highest productivity was obtained for the strain grown under non-induced conditions. It was 30-fold higher than that obtained for tyrosine-induced wild-type cells. PMID:19420686

  5. Measurement of Liquid Diffusion Coefficients of Aqueous Solutions of Glycine, L-Alanine, L-Valine and L-Isoleucine by Holographic Interferometry

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 李继定; 马沛生; 夏淑倩

    2005-01-01

    The diffusion coefficients of aqueous solutions ofglycine, L-alanine, L-valine and L-isoleucine at 298.15 K were determined by holographic interferometry with accuracy and promptness while without disturbance. The density and viscosity of these solutions were also determined. According to original Gordon model, a model for correlating the diffusion coefficients of amino acids in aqueous solutions was developed and applied. The results showed that this model provided significant convenience in correlation of diffusion coefficients for amino acids system.

  6. Measurement of Liquid Diffusion Coefficients of Aqueous Solutions of Glycine, L-Alanine, L-Valine and L-Isoleucine by Holographic Interferometry%激光全息干涉法测量甘氨酸、L-丙氨酸、L-缬氨酸和异亮氨酸液相扩散系数的研究

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 李继定; 马沛生; 夏淑倩

    2005-01-01

    The diffusion coefficients of aqueous solutions ofglycine, L-alanine, L-valine and L-isoleucine at 298.15 K were determined by holographic interferometry with accuracy and promptness while without disturbance. The density and viscosity of these solutions were also determined. According to original Gordon model, a model for correlating the diffusion coefficients of amino acids in aqueous solutions was developed and applied. The results showed that this model provided significant convenience in correlation of diffusion coefficients for amino acids system.

  7. Transfer Partial Molar Isentropic Compressibilities of ( l-Alanine/ l-Glutamine/Glycylglycine) from Water to 0.512 {mol} \\cdot {kg}^{-1} Aqueous {KNO}3/0.512 {mol} \\cdot {kg}^{-1} Aqueous {K}2{SO}4 Solutions Between 298.15 K and 323.15 K

    Science.gov (United States)

    Riyazuddeen; Gazal, Umaima

    2013-03-01

    Speeds of sound of ( l-alanine/ l-glutamine/glycylglycine + 0.512 {mol}\\cdot {kg}^{-1} aqueous {KNO}3/0.512 {mol}\\cdot {kg}^{-1} aqueous {K}2{SO}4) systems have been measured for several molal concentrations of amino acid/peptide at different temperatures: T = (298.15 to 323.15) K. Using the speed-of-sound and density data, the parameters, partial molar isentropic compressibilities φ _{kappa }0 and transfer partial molar isentropic compressibilities Δ _{tr} φ _{kappa }0, have been computed. The trends of variation of φ _{kappa }0 and Δ _{tr} φ _{kappa }0 with changes in molal concentration of the solute and temperature have been discussed in terms of zwitterion-ion, zwitterion-water dipole, ion-water dipole, and ion-ion interactions operative in the systems.

  8. Ruthenium-nitrosyl complexes with glycine, L-alanine, L-valine, L-proline, D-proline, L-serine, L-threonine, and L-tyrosine: synthesis, X-ray diffraction structures, spectroscopic and electrochemical properties, and antiproliferative activity.

    Science.gov (United States)

    Rathgeb, Anna; Böhm, Andreas; Novak, Maria S; Gavriluta, Anatolie; Dömötör, Orsolya; Tommasino, Jean Bernard; Enyedy, Eva A; Shova, Sergiu; Meier, Samuel; Jakupec, Michael A; Luneau, Dominique; Arion, Vladimir B

    2014-03-01

    The reactions of [Ru(NO)Cl5](2-) with glycine (Gly), L-alanine (L-Ala), L-valine (L-Val), L-proline (L-Pro), D-proline (D-Pro), L-serine (L-Ser), L-threonine (L-Thr), and L-tyrosine (L-Tyr) in n-butanol or n-propanol afforded eight new complexes (1-8) of the general formula [RuCl3(AA-H)(NO)](-), where AA = Gly, L-Ala, L-Val, L-Pro, D-Pro, L-Ser, L-Thr, and L-Tyr, respectively. The compounds were characterized by elemental analysis, electrospray ionization mass spectrometry (ESI-MS), (1)H NMR, UV-visible and ATR IR spectroscopy, cyclic voltammetry, and X-ray crystallography. X-ray crystallography studies have revealed that in all cases the same isomer type (from three theoretically possible) was isolated, namely mer(Cl),trans(NO,O)-[RuCl3(AA-H)(NO)], as was also recently reported for osmium analogues with Gly, L-Pro, and D-Pro (see Z. Anorg. Allg. Chem. 2013, 639, 1590-1597). Compounds 1, 4, 5, and 8 were investigated by ESI-MS with regard to their stability in aqueous solution and reactivity toward sodium ascorbate. In addition, cell culture experiments in three human cancer cell lines, namely, A549 (nonsmall cell lung carcinoma), CH1 (ovarian carcinoma), and SW480 (colon carcinoma), were performed, and the results are discussed in conjunction with the lipophilicity of compounds. PMID:24555845

  9. Analysis of β-N-methylamino-L-alanine (L-BMAA) neurotoxicity in rat cerebellum.

    Science.gov (United States)

    Muñoz-Sáez, Emma; de Munck García, Estefanía; Arahuetes Portero, Rosa Ma; Martínez, Ana; Solas Alados, Ma Teresa; Miguel, Begoña Gómez

    2015-05-01

    Due to its structural similarity to glutamate, L-BMAA could be a trigger for neurodegenerative disorders caused by changes in the intracellular medium, such as increased oxidative stress, mitochondrial dysfunction, impaired synthesis and protein degradation and the imbalance of some enzymes. It is also important to note that according to some published studies, L-BMAA will be incorporated into proteins, causing the alteration of protein homeostasis. Neuronal cells are particularly prone to suffer damage in protein folding and protein accumulation because they have not performed cellular division. In this work, we will analyse the cerebellum impairment triggered by L-BMAA in treated rats. The cerebellum is one of the most important subcortical motor centres and ensures that movements are performed with spatial and temporal precision. Cerebellum damage caused by L-BMAA can contribute to motor impairment. To characterize this neurodegenerative pathology, we first carried out ultrastructure analysis in Purkinje cells showing altered mitochondria, endoplasmic reticulum (ER), and Golgi apparatus (GA). We then performed biochemical assays of GSK3 and TDP-43 in cerebellum, obtaining an increase of both biomarkers with L-BMAA treatment and, finally, performed autophagy studies that revealed a higher level of these processes after treatment. This work provides evidence of cerebellar damage in rats after treatment with L-BMAA. Three months after treatment, affected rats cannot restore the normal functions of the cerebellum regarding motor coordination and postural control. PMID:25898785

  10. XPS investigation on the structure of two dipeptides studied as models of self-assembling oligopeptides: comparison between experiments and theory

    International Nuclear Information System (INIS)

    The adsorption on TiO2 surface of two dipeptides AE (L-alanine-L-glutamic acid) and AK (L-alanine-L-lysine), that are 'building blocks' of the more complex self-complementary amphiphilic oligopeptides and are therefore a good model in the interpretation of the complex peptide spectra, has been investigated both theoretically and experimentally. The chemical structure and composition of thin films of both dipeptides on TiO2 were investigated by XPS (X-ray photoelectron spectroscopy). Theoretical ab-initio calculations (ΔSCF) were also performed to simulate the spectra allowing a direct comparison between experiment and theory

  11. XPS investigation on the structure of two dipeptides studied as models of self-assembling oligopeptides: comparison between experiments and theory

    Science.gov (United States)

    Battocchio, C.; Iucci, G.; Dettin, M.; Monti, S.; Carravetta, V.; Polzonetti, G.

    2008-03-01

    The adsorption on TiO2 surface of two dipeptides AE (L-alanine-L-glutamic acid) and AK (L-alanine-L-lysine), that are 'building blocks' of the more complex self-complementary amphiphilic oligopeptides and are therefore a good model in the interpretation of the complex peptide spectra, has been investigated both theoretically and experimentally. The chemical structure and composition of thin films of both dipeptides on TiO2 were investigated by XPS (X-ray photoelectron spectroscopy). Theoretical ab-initio calculations (ΔSCF) were also performed to simulate the spectra allowing a direct comparison between experiment and theory.

  12. Animal model for identifying therapetucually useful compounds for the treatment of sporadic amyotrophic lateral sclerosis

    OpenAIRE

    Gil Ayuso-Gontán, Carmen; Martínez, Ana

    2012-01-01

    [EN] The invention relates to a method for identifying compounds that are potentially useful for the treatment of sporadic amyotrophic lateral sclerosis (ALS), comprising the use of an animal model of rats, developed by means of the administration of β-Ν-methylamino-L-alanine (L-BMAA)

  13. The effect of organic nitrogen sources on recombinant glucoamylase production by Aspergillus niger in chemostat culture

    NARCIS (Netherlands)

    Swift, R.J.; Karandikar, A.; Griffen, A.M.; Punt, P.J.; Hondel, C.A.M.J.J. van den; Robson, G.D.; Trinci, A.P.J.; Wiebe, M.G.

    2000-01-01

    Aspergillus niger B1, a recombinant strain carrying 20 extra copies of the native glucoamylase gene, was grown in glucose-limited chemostat cultures supplemented with various organic nitrogen sources (dilution rate 0.12 ± 0.01 h-1, pH 5.4). In cultures supplemented with L-alanine, L-methionine, casa

  14. A fast method for ionized food identification: EPR

    International Nuclear Information System (INIS)

    Electronic paramagnetic resonance allows the detection of ionized food only after dry storage, avoiding reaction of radicals with water. Dry and solid parts are used for analysis (bones for meat and fish, kernels for fruits). Dosimetry is possible by EPR spectrometry of alanine-L fixed on products treated in industrial irradiators

  15. Neutron inelastic scattering from amino acids

    International Nuclear Information System (INIS)

    Neutron incoherent inelastic scattering technique is used for studying the extensive hydrogen bonding that connects the molecules together and gives the structure cohesion in three dimension in amino acids. Results on five amino acids namely, α-glycine, DL-alanine, L-valine, L-tyrosine and L-phenyl-alanine having different side groups are reported and compared with those from other methods. The main emphasis is on the torsional motions of NH3+ and CH3 groups. (K.B.)

  16. Excitatory amino acid b-N-methylamino-L-alanine is a putative environmental neurotoxin

    OpenAIRE

    SRDJAN LOPIČIĆ; MARIJA BRATIĆ-STANOJEVIĆ; PATHAK DHRUBA; DRAGAN PAVLOVIĆ; MILICA PROSTRAN; VLADIMIR NEDELJKOV

    2011-01-01

    The amino acid b-N-methylamino-L-alanine (L-BMAA) has been associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex in three distinct western Pacific populations. The putative neurotoxin is produced by cyanobacteria, which live symbiotically in the roots of cycad trees. L-BMAA was thought to be a threat only to those few populations whose diet and medicines rely heavily on cycad seeds. However, the recent discovery that cyanobacteria from diverse terrestrial, freshwater...

  17. Animal Models of Brain Maldevelopment Induced by Cycad Plant Genotoxins

    OpenAIRE

    Kisby, Glen E.; Moore, Holly; Spencer, Peter S.

    2013-01-01

    Cycads are long-lived tropical and subtropical plants that contain azoxyglycosides (e.g., cycasin, macrozamin) and neurotoxic amino acids (notably β-N-methylamino-L-alanine L-BMAA), toxins that have been implicated in the etiology of a disappearing neurodegenerative disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex that has been present in high incidence among three genetically distinct populations in the western Pacific. The neuropathology of amyotrophic lateral sclero...

  18. Identification of a Vibrio cholerae chemoreceptor that senses taurine and amino acids as attractants

    OpenAIRE

    So-ichiro Nishiyama; Yohei Takahashi; Kentaro Yamamoto; Daisuke Suzuki; Yasuaki Itoh; Kazumasa Sumita; Yumiko Uchida; Michio Homma; Katsumi Imada; Ikuro Kawagishi

    2016-01-01

    Vibrio cholerae, the etiological agent of cholera, was found to be attracted by taurine (2-aminoethanesulfonic acid), a major constituent of human bile. Mlp37, the closest homolog of the previously identified amino acid chemoreceptor Mlp24, was found to mediate taxis to taurine as well as L-serine, L-alanine, L-arginine, and other amino acids. Methylation of Mlp37 was enhanced upon the addition of taurine and amino acids. Isothermal titration calorimetry demonstrated that a purified periplasm...

  19. Acute effects of a commercially-available pre-workout supplement on markers of training: a double-blind study

    OpenAIRE

    Outlaw, Jordan J; Wilborn, Colin D; Smith-Ryan, Abbie E; Hayward, Sara E; Urbina, Stacie L; Taylor, Lem W.; Foster, Cliffa A

    2014-01-01

    Background Pre-workout supplements containing numerous ingredients claim to increase performance and strength. Product-specific research is important for identifying efficacy of combined ingredients. The purpose of this study was to evaluate the effects of a proprietary pre-workout dietary supplement containing creatine monohydrate, beta-alanine, L-Tarurine, L-Leucine, and caffeine, on anaerobic power, muscular strength, body composition, and mood states. Methods In a double-blind, randomized...

  20. L-alanine distribution in the growth pyramids of TGS crystals and its influence on the growth, switching and domain structure

    Energy Technology Data Exchange (ETDEWEB)

    Brezina, B.; Havrankova, M.

    1985-06-01

    The full-faced crystals of triglycine sulphate (TGS) and deuterated homologs substituted by L-alanine (LATGS and LADTGS, resp.) were grown from growth solutions with various concentrations of the substituent. The distribution of L, alanine (L,al) in various growth pyramids of crystals was measured by the electrical switching method. The stability of domain structure of doped crystals was studied by the liquid crystal method. (author).

  1. L-alanine distribution in the growth pyramids of TGS crystals and its influence on the growth, switching and domain structure

    International Nuclear Information System (INIS)

    The full-faced crystals of triglycine sulphate (TGS) and deuterated homologs substituted by L-alanine (LATGS and LADTGS, resp.) were grown from growth solutions with various concentrations of the substituent. The distribution of L, alanine (L,al) in various growth pyramids of crystals was measured by the electrical switching method. The stability of domain structure of doped crystals was studied by the liquid crystal method. (author)

  2. CO2 Capture from Flue gas using Amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    naturally occurring substances, and partly because they have desirable properties, such as lower vapor pressures and higher stability against oxidative degradation. One important feature of these new solvents is the formation of solids upon CO2 absorption, which happens especially at higher CO2 loadings and...... of the components in the apparatus. Ideally, measurements in the full temperature range for desorption, which usually needs approximately 393 K (120 ºC), would be desirable. Using the 2 apparatuses, CO2 solubility in aqueous solutions of MEA and the potassium salts of taurine, glycine, L-alanine, L...

  3. Searching for a link between the L-BMAA neurotoxin and amyotrophic lateral sclerosis: a study protocol of the French BMAALS programme

    OpenAIRE

    Delzor, Aurélie; Couratier, Philippe; Boumédiène, Farid; Nicol, Marie; Druet-Cabanac, Michel; Paraf, François; Méjean, Annick; Ploux, Olivier; Leleu, Jean-Philippe; Brient, Luc; Lengronne, Marion; Pichon, Valérie; Combès, Audrey; El Abdellaoui, Saïda; BONNETERRE, Vincent

    2014-01-01

    Introduction Amyotrophic lateral sclerosis (ALS) is the most common motor neurone disease. It occurs in two forms: (1) familial cases, for which several genes have been identified and (2) sporadic cases, for which various hypotheses have been formulated. Notably, the β-N-methylamino-L-alanine (L-BMAA) toxin has been postulated to be involved in the occurrence of sporadic ALS. The objective of the French BMAALS programme is to study the putative link between L-BMAA and ALS. Methods and analysi...

  4. Synthesis and characterization of mixed ligand complexes of bio-metals with pyrimidine nucleoside (uridine) and amino acids

    Indian Academy of Sciences (India)

    P Rabindra Reddy; A Mohan Reddy

    2000-12-01

    The mixed ligand complexes of Cu(II), Ni(II) and Co(II) with uridine and amino acids, L-alanine, L-phenylalanine and L-tryptophan were synthesized and characterized by elemental analysis, conductivity data, infrared spectra, electronic spectra and magnetic susceptibility data. In these complexes, the nucleoside (uridine) acts as a monodentate ligand coordinating through O(4) under the conditions of investigation, whereas the amino acids coordinate through the carboxylate oxygen and the amino nitrogen. Distorted octahedral geometry for Cu(II) and octahedral geometries for both Ni(II) and Co(II) are proposed.

  5. Estrogen receptor α AF-2 mutation results in antagonist reversal and reveals tissue selective function of estrogen receptor modulators

    OpenAIRE

    Arao, Yukitomo; Hamilton, Katherine J.; Ray, Manas K.; Scott, Gregory; Mishina, Yuji; Korach, Kenneth S.

    2011-01-01

    The estrogen receptor (ER) is a ligand-dependent transcription factor containing two transcriptional activation domains. AF-1 is in the N terminus of the receptor protein and AF-2 activity is dependent on helix 12 of the C-terminal ligand-binding domain. Two point mutations of leucines 543 and 544 to alanines (L543A, L544A) in helix 12 minimized estrogen-dependent transcriptional activation and reversed the activity of the estrogen antagonists ICI182780 (ICI) and tamoxifen (TAM) into agonists...

  6. Use of vibrational spectroscopy to study protein and DNA structure, hydration, and binding of biomolecules: A combined theoretical and experimental approach

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.; Jürgensen, Vibeke Würtz; Claussen, Anetta;

    2006-01-01

    We report on our work with vibrational absorption, vibrational circular dichroism, Raman scattering, Raman optical activity, and surface-enhanced Raman spectroscopy to study protein and DNA structure, hydration, and the binding of ligands, drugs, pesticides, or herbicides via a combined theoretical...... and experimental approach. The systems we have studied systematically are the amino acids (L-alanine, L-tryptophan, and L-histidine), peptides (N-acetyl L-alanine N'-methyl amide, N-acetyl L-tryptophan N'-methyl amide, N-acetyl L-histidine N'-methyl amide, L-alanyl L-alanine, tri-L-serine, N-acetyl L......-alanine L-ploline L-tyrosine N'-methyl amide, Leu-enkephalin, cyclo-(gly-L-pro), N-acetyl (L-alanine)(n) N'-methyl amide), 3-methyl indole, and a variety of small molecules (dichlobenil and 2,6-dochlorobenzamide) of relevance to the protein systems under study. We have used molecular mechanics, the SCC...

  7. EFFECTS OF L-PHENYLALANINE ON THE RADIATION SYNTHESIS OF POLY (N,N'-METHYLENEBISACRYLAMIDE-co-4-VINYLPYRIDINE) (MICRO)GELS

    Institute of Scientific and Technical Information of China (English)

    Qing-de Chen; Xing-hai Shen; Hong-cheng Gao

    2005-01-01

    The effects of L-phenylalanine (L-Phe) on the synthesis ofpoly(N,N'-methylenebisacrylamide-co-4-vinylpyridine)(poly(Bis-co-4-VP)) (micro)gels by T-ray irradiation were studied. The addition of L-Phe could not only decrease the gelation dose (Dg) of the synthesis obviously, but also transform the morphology of copolymer from microgel to gel. In addition, the swelling ability of the (micro)gels was also affected in the presence of L-Phe. The decrease of Dg was ascribed to the effect of pH, while the transformation of the morphology was ascribed to the effect of L-Phe on the stability of the poly(Bis-co-4-VP) microgel. Such an effect was confirmed further as compared with the effects of L-alanine, L-glutamic acid, L-arginine, sulfuric acid and aqueous ammonia.

  8. Synthesis and biodistribution of six novel 99mTc complexes of 2-hydroxybenzaldehyde-amino acid Schiff bases

    International Nuclear Information System (INIS)

    For the purpose of developing novel diagnostic pharmaceuticals of 99mTc-labeled small-size complexes, six novel complexes of 99mTc-2-hydroxybenzaldehyde-amino acid Schiff bases were designed and synthesized, and their biodistributions in mice were investigated. All the compounds were obtained in radiochemical yields higher than 90% at optimal conditions, and poor uptakes in muscle, brain, heart and tumor were commonly observed with rapid blood clearance. Potentiality was revealed of good kidney imaging by 2-hydroxybenzaldehyde-alanine (L2) complex within 40 min post-injection. Good bone uptake of 2-hydroxybenzaldehyde-histidine (L4) and 2-hydroxybenzaldehyde-aspartic acid (L5) complexes, high spleen accumulation of 2-hydroxybenzaldehyde-glycine (L1) and 2-hydroxybenzaldehyde-cysteine (L3) complexes, and non-specific biodistribution of 2-hydroxybenzaldehyde-glutamic acid (L6) complex were demonstrated

  9. Excitatory amino acid b-N-methylamino-L-alanine is a putative environmental neurotoxin

    Directory of Open Access Journals (Sweden)

    VLADIMIR NEDELJKOV

    2011-04-01

    Full Text Available The amino acid b-N-methylamino-L-alanine (L-BMAA has been associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex in three distinct western Pacific populations. The putative neurotoxin is produced by cyanobacteria, which live symbiotically in the roots of cycad trees. L-BMAA was thought to be a threat only to those few populations whose diet and medicines rely heavily on cycad seeds. However, the recent discovery that cyanobacteria from diverse terrestrial, freshwater, and saltwater ecosystems around the world produce the toxin requires a reassessment of whether it poses a larger health threat. Therefore, it is proposed that monitoring L-BMAA levels in cyanobacteria-contaminated water supplies might be prudent.

  10. Morphometric and neurochemical alterations found in l-BMAA treated rats.

    Science.gov (United States)

    de Munck, Estefanía; Muñoz-Sáez, Emma; Miguel, Begoña G; Solas, M Teresa; Martínez, Ana; Arahuetes, Rosa M

    2015-05-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive muscle paralysis that reflects the motoneurons' degeneration. Several studies support the relationship between β-N-methylamino-l-alanine (l-BMAA), a neurotoxic amino acid produced by cyanobacteria and diatoms, and the sporadic occurrence of ALS and other neurodegenerative diseases. Therefore, the study of its neurotoxicity mechanisms has assumed great relevance in recent years. Recently, our research team has proposed a sporadic ALS animal model by l-BMAA administration in rats, which displays many pathophysiological features of human ALS. In this paper, we deepen the characterization of this model corroborating the occurrence of alterations present in ALS patients such as decreased muscle volume, thinning of the motor cortex, enlarged brain's lateral ventricles, and alteration of both bulbar nuclei and neurotransmitters' levels. Therefore, we conclude that l-BMAA treated rats could be a good model which mimics degenerative features that ALS causes in humans. PMID:26002186

  11. β-N-methylamino-L-alanine induces changes in both GSK3 and TDP-43 in human neuroblastoma.

    Science.gov (United States)

    Muñoz-Saez, Emma; de Munck, Estefanía; Arahuetes, Rosa M; Solas, M Teresa; Martínez, Ana M; Miguel, Begoña G

    2013-01-01

    β-N-methylamino-L-alanine (L-BMAA) is a neurotoxic amino acid produced by most cyanobacteria, which are extensively distributed in different environments all over the world. L-BMAA has been linked to a variety of neurodegenerative diseases. This work aims to analyze the toxicological action of L-BMAA related to alterations observed in different neurodegenerative illness as Alzheimer disease and amyotrophic lateral sclerosis. Our results demonstrate that neuroblastoma cells treated with L-BMAA show an increase in glycogen synthase kinase 3 β (GSk3β) and induce accumulation of TAR DNA-binding protein 43 (TDP-43) truncated forms (C-terminal fragments), phosphorylated  and high molecular weight forms of TDP-43, that appears frequently in some neurodegenerative diseases. PMID:23665941

  12. Concentration dependences of density, viscosity, refractive index, and other derived properties of metoclopramide aqueous solutions at 303.15 K

    Science.gov (United States)

    Sawale, R. T.; Deosarkar, S. D.; Kalyankar, T. M.

    2015-07-01

    Density ( ρ), viscosity ( η) and refractive index ( n D) of an antiemetic drug metoclopramide (4-amino-5-chloro- N-(2-(diethylamino)ethyl)-2-methoxybenzamide hydrochloride) solutions containing amino acids (glycine, D-alanine, L-cystine and L-histidine) were measured in the concentration range 0.01-0.17 mol/dm3 at 303.15 K. The apparent molar volume (φv) of this drug in aqueous amino acid solutions was calculated from the density data and fitted to the Massons relation, and the partial molar volume φ{v/0} of the drug was determined graphically. The partial molar volumes of transfer (Δtrφ{v/0}) of drug at infinite dilution from pure water to aqueous amino acid solutions were calculated and interpreted in terms of different interactions between the drug and amino acids.

  13. Strecker degradation of amino acids promoted by a camphor-derived sulfonamide.

    Science.gov (United States)

    Carvalho, M Fernanda N N; Ferreira, M João; Knittel, Ana S O; Oliveira, Maria da Conceição; Costa Pessoa, João; Herrmann, Rudolf; Wagner, Gabriele

    2016-01-01

    A camphor-derived sulfonimine with a conjugated carbonyl group, oxoimine 1 (O2SNC10H13O), reacts with amino acids (glycine, L-alanine, L-phenylalanine, L-leucine) to form a compound O2SNC10H13NC10H14NSO2 (2) which was characterized by spectroscopic means (MS and NMR) and supported by DFT calculations. The product, a single diastereoisomer, contains two oxoimine units connected by a -N= bridge, and thus has a structural analogy to the colored product Ruhemann´s purple obtained by the ninhydrin reaction with amino acids. A plausible reaction mechanism that involves zwitterions, a Strecker degradation of an intermediate imine and water-catalyzed tautomerizations was developed by means of DFT calculations on potential transition states. PMID:27340465

  14. Strecker degradation of amino acids promoted by a camphor-derived sulfonamide

    Science.gov (United States)

    Ferreira, M João; Knittel, Ana S O; Oliveira, Maria da Conceição; Costa Pessoa, João; Herrmann, Rudolf; Wagner, Gabriele

    2016-01-01

    Summary A camphor-derived sulfonimine with a conjugated carbonyl group, oxoimine 1 (O2SNC10H13O), reacts with amino acids (glycine, L-alanine, L-phenylalanine, L-leucine) to form a compound O2SNC10H13NC10H14NSO2 (2) which was characterized by spectroscopic means (MS and NMR) and supported by DFT calculations. The product, a single diastereoisomer, contains two oxoimine units connected by a –N= bridge, and thus has a structural analogy to the colored product Ruhemann´s purple obtained by the ninhydrin reaction with amino acids. A plausible reaction mechanism that involves zwitterions, a Strecker degradation of an intermediate imine and water-catalyzed tautomerizations was developed by means of DFT calculations on potential transition states.

  15. Fast enzymatic preparation of L-DOPA from tyrosine and molecular oxygen: a potential method for preparing [15O]L-DOPA

    International Nuclear Information System (INIS)

    A fast, simple and inexpensive enzymatic preparation of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) from molecular oxygen and tyrosine using mushroom tyrosinase is described. The theoretical incubation time for production of [15O]L-DOPA with maximal specific activity from [15O]O2 can be calculated to be about 3 min. In practice, using a specially-designed glass reaction chamber to facilitate the incorporation of gaseous molecular oxygen into L-DOPA with zero lag-time, a 3 min reaction with 1% oxygen in nitrogen results in the formation of approx. 3.9 μmol of L-DOPA, representing conversion of about 14% of the tyrosine substrate. Given access to a supply of [15O]O2, the method should be applicable to the preparation of [15O]L-DOPA for use as a PET tracer. (author)

  16. Thermodynamic Modeling of Several Aqueous Alkanol Solutions Containing Amino Acids with the Perturbed-Chain Statistical Associated Fluid Theory Equation of State

    DEFF Research Database (Denmark)

    Ferreira, Luisa; Breil, Martin Peter; Pinho, S. P.;

    2009-01-01

    and a fluid phase. The hypothetical melting properties of each amino acid were fitted, to accurately correlate the solubilities in pure water. Only one temperature independent binary parameter is required for each amino acid/solvent pair. The model can accurately describe the solubility of the amino......The perturbed-chain statistical associated fluid theory EoS was applied to model the solubilities of glycine, DL-alanine, L-serine, L-threonine, and L-isoleucine in pure water, pure alcohols (ethanol, I-propanol, and 2-propanol) and in mixed solvent systems. Three pure component nonassociating...... parameters for the amino acids were fitted to the densities, activity and osmotic coefficients, vapor pressures, and water activity of their aqueous solutions. The solubilities of amino acids in pure and mixed solvent systems were calculated on the basis of the phase equilibrium conditions for a pure solid...

  17. Characterization of free and alginate-polylysine-alginate microencapsulated Erwinia herbicola for the conversion of ammonia, pyruvate, and phenol into L-tyrosine

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd-George, I.; Chang, T.M.S. [McGill Univ., Montreal, Quebec (Canada)

    1995-12-20

    The whole cell tyrosine phenol-lyase activity of Erwinia herbicola was microencapsulated. The authors studied the use of this for the conversion of ammonia and pyruvate along with phenol or catechol, respectively, into L-tyrosine or dihydroxyphenyl-L-alanine (L-dopa). The reactions are relevant to the development of new methods for the production of L-tyrosine and L-dopa. The growth of E. herbicola at temperatures from 22 C to 32 C is stable, since at these temperatures the cells grow up to the stationary phase and remain there for at least 10 h. At 37 C the cells grow rapidly, but they also enter the death phase rapidly. There is only limited growth of E. herbicola at 42 C. Whole cells of E. herbicola were encapsulated within alginate-polylysine-alginate microcapsules (916 {+-} 100 {micro}m, mean {+-} std. dev.). The TPL activity of the cells catalyzed the production of L-tyrosine or dihydroxyphenol-L-alanine (L-dopa) from ammonia, pyruvate, and phenol or catechol, respectively. In the production of tyrosine, an integrated equation based on an ordered ter-uni rapid equilibrium mechanism can be used to find the kinetic parameters of TPL. In an adequately stirred system, the apparent values of the kinetic parameters of whole cell TPL are equal whether the cells are free or encapsulated. The apparent K{sub M} of tyrosine varies with the amount of whole cells in the system, ranging from 0.2 to 0.3 mM. The apparent K{sub M} for phenol is 0.5 mM. The apparent K{sub M} values for pyruvate and ammonia are an order of magnitude greater for whole cells than they are for the cell free enzyme.

  18. Mechanistic aspects of ligand substitution on [(H2O)(tap)2RuORu(tap)2(H2O)]2+ {tap=2-(m-tolylazo)pyridine} ion by three glycine-containing dipeptides in aqueous medium at physiological pH

    Indian Academy of Sciences (India)

    Arup Mandal; Subala Mondal; Parnajyoti Karmakar; Biplab K Bera; Subhasis Mallick; Alak K Ghosh

    2012-05-01

    The interaction of the title complex with selected glycine-containing dipeptides(L-L'H) such as glycyl-glycine(L-L1H), glycyl-L-alanine (L-L2H) and glycyl-L-leucine(L-L3H) has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand] and temperature. The reaction has been monitored at 600 nm where the spectral difference between the reactant and product is a maximum. At pH 7.4, the interaction with studied dipeptides shows two parallel steps. i.e., it shows a non-linear dependence on the concentration of dipeptides; both processes are ligand-dependent. The rate constants for the processes are: k1 ∼ 10−3 s-1 and k2 ∼ 10−5 s-1. The activation parameters were calculated from Eyring plots. Based on the kinetic and activation parameters an associative interchange mechanism is proposed for the interaction processes. From the temperature dependence of the outer sphere association equilibrium constant, the thermodynamic parameters were also calculated. The product of the reaction has been characterized by IR and ESI-mass spectroscopic analysis.

  19. Tracking dipeptides at work-uptake and intracellular fate in CHO culture.

    Science.gov (United States)

    Sánchez-Kopper, Andres; Becker, Max; Pfizenmaier, Jennifer; Kessler, Christian; Karau, Andreas; Takors, Ralf

    2016-12-01

    Market demands for monoclonal antibodies (mAbs) are steadily increasing worldwide. As a result, production processes using Chinese hamster ovary cells (CHO) are in the focus of ongoing intensification studies for maximizing cell-specific and volumetric productivities. This includes the optimization of animal-derived component free (ADCF) cultivation media as part of good cell culture practice. Dipeptides are known to improve CHO culture performance. However, little or even conflicting assumptions exist about their putative import and functionality inside the cells. A set of well-known performance boosters and new dipeptide prospects was evaluated. The present study revealed that dipeptides are indeed imported in the cells, where they are decomposed to the amino acids building blocks. Subsequently, they are metabolized or, unexpectedly, secreted to the medium. Monoclonal antibody production boosting additives like L-alanine-L-glutamine (AQ) or glycyl-L-glutamine (GQ) can be assigned to fast or slow dipeptide uptake, respectively, thus pinpointing to the need to study dipeptide kinetics and to adjust their feeding individually for optimizing mAb production. PMID:27447702

  20. Biconical tapered optical fiber biosensor for measuring refractive index of a-amino acids in aqueous D-glucose and sucrose solution

    Science.gov (United States)

    Zibaii, M. I.; Latifi, H.; Karami, M.; Gholami, M.; Hosseini, S. M.; Ghezelayagh, M. H.

    2010-04-01

    A single-mode biconical tapered optical fiber (BTOF) sensor was utilized for sensing the variation of refractive index (RI) with concentration of D-glucose in double distilled deionized water and measuring of RI of amino acids (AAs) in carbohydrate solutions. This method showed a rewarding ability in understanding the basis of biomolecular interactions in biological systems. The BTOF is fabricated by heat pulling method, utilizing a CO2 laser. The detection limit of the BTOF was 50 ppb for the D-glucose concentration ranging from 0 to 80 ppm, and RI detection limit corresponding to these concentrations in the range at 1.3333 to 1.3404 was 5.4×10-6 as a refractometer sensor. The response of the BTOF shows that the different kinds of interactions of various groups of AAs such as L-alanine, L-leucine, and L-cystein with D-glucose, sucrose and water molecules depend on functional groups in AAs such as OH, SH;CH2;NH3+ ,COO-. These results can be interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.

  1. Thermodynamics of Carboxyl Group′s Protonation of α -amino Acids in Water-Ethanol Mixtures at 298.15K%α-氨基酸在水-乙醇中羧基质子化热力学

    Institute of Scientific and Technical Information of China (English)

    厉刚; 林瑞森; 宗汉兴

    2000-01-01

    Enthalpy changes for the protonation of carboxyl group of four α-amino acids(glycine,L-α-alanine,L-valine and L-serine) were measured in water-ethanol mixtures (10- 70wt%) at 298.15K using LKB-2277 Bioactivity Monitor.The corresponding entropy and Gibbs energy changes were also calculated.The results show that both enthalpy changes and entropy changes are favorable to the protonation of carboxyl groups of the investigated amino acids in water-ethanol mixtures.However,the influence of the composition of ethanol in the mixed solvents on the enthalpy change and entropy changes is complicated.Both sδ and sδ ,the differences of enthalpy changes and entropy changes in mixed solvents and in pure water respectively,show a minimum approximately at xEtOH=0.1.The effects of side chains on the enthalpy change and entropy changes were also investigated using the proton transfer process between glycine and the other three amino acids.The results demonstrate that the proton transfer processes for alanine and valine are spontaneous but not for serine,which could be interpreted in terms of the electrostatic interaction between amino group and carboxyl group within the molecule and the interaction between carboxyl group and the solvent.

  2. The Amino Acid Composition of the Sutter's Mill Carbonaceous Chondrite

    Science.gov (United States)

    Glavin, D. P.; Burton, A. S.; Elsila, J. E.; Dworkin, J. P.; Yin, Q. Z.; Cooper, G.; Jenniskens, P.

    2012-01-01

    In contrast to the Murchison meteorite which had a complex distribution of amino acids with a total C2 to Cs amino acid abundance of approx.14,000 parts-per-billion (ppb) [2], the Sutters Mill meteorite was found to be highly depleted in amino acids. Much lower abundances (approx.30 to 180 ppb) of glycine, beta-alanine, L-alanine and L-serine were detected in SM2 above procedural blank levels indicating that this meteorite sample experienced only minimal terrestrial amino acid contamination after its fall to Earth. Carbon isotope measurements will be necessary to establish the origin of glycine and beta-alanine in SM2. Other non-protein amino acids that are rare on Earth, yet commonly found in other CM meteorites such as aaminoisobutyric acid (alpha-AIB) and isovaline, were not identified in SM2. However, traces of beta-AIB (approx.1 ppb) were detected in SM2 and could be" extraterrestrial in origin. The low abundances of amino acids in the Sutter's Mill meteorite is consistent with mineralogical evidence that at least some parts of the Sutter's Mill meteorite parent body experienced extensive aqueous and/or thermal alteration.

  3. Electrocatalytic oxidation of some amino acids on a nickel-curcumin complex modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Majdi, S. [Department of Chemistry, Faculty of Science, K.N. Toosi University of Technology, P.O. Box 16315-1618, Tehran (Iran, Islamic Republic of); Jabbari, A. [Department of Chemistry, Faculty of Science, K.N. Toosi University of Technology, P.O. Box 16315-1618, Tehran (Iran, Islamic Republic of)]. E-mail: jabbari@kntu.ac.ir; Heli, H. [Institute of Biochemistry and Biophysics, University of Tehran, Tehran (Iran, Islamic Republic of); Moosavi-Movahedi, A.A. [Institute of Biochemistry and Biophysics, University of Tehran, Tehran (Iran, Islamic Republic of)

    2007-04-01

    This study investigated the electrocatalytic oxidation of alanine, L-arginine, L-phenylalanine, L-lysine and glycine on poly-Ni(II)-curcumin film (curcumin: 1,7-bis [4-hydroxy-3-methoxy phenyl]-1,6-heptadiene-3,5-dione) electrodeposited on a glassy carbon electrode in alkaline solution. The process of oxidation and its kinetics were established by using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques. Voltammetric studies indicated that in the presence of amino acids the anodic peak current of low valence nickel species increased, followed by a decrease in the corresponding cathodic current. This indicates that amino acids were oxidized on the redox mediator which was immobilized on the electrode surface via an electrocatalytic mechanism. Using Laviron's equation, the values of {alpha} and k {sub s} for the immobilized redox species were determined as 0.43 {+-} 0.03 and 2.47 {+-} 0.02 x 10{sup 6} s{sup -1}, respectively. The rate constant, the electron transfer coefficient and the diffusion coefficients involved in the electrocatalytic oxidation of amino acids were determined.

  4. Volumetric behaviour of amino acids and their group contributions in aqueous lactose solutions at different temperatures

    International Nuclear Information System (INIS)

    Densities, ρ, for glycine, L-alanine, L-valine, and L-leucine [(0.05 to 0.30) m] in aqueous lactose solutions ranging from pure water to 6 mass% lactose were determined at T = (293.15, 298.15, 303.15, and 308.15) K. The density was used to compute apparent molar volume, Vφ, partial molar volume at infinite dilution, Vφo, and experimental slope, SV were obtained and interpreted in terms of solute-solvent and solute-solute interactions. These data were used to calculate the (∂Vφ0/∂T)P values. The partial molar volume of transfer, ΔVφ0 from water to aqueous lactose solutions at infinite dilution has also been calculated. In addition to this, the linear correlation of Vφ0 with number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of NH3+COO-, and CH2 groups to Vφ0.

  5. Physicochemical Properties of Amino Acids in Aqueous Caffeine Solution at 25, 30, 35 and 40 ℃

    Institute of Scientific and Technical Information of China (English)

    ALI A.; SABIR S.; SHAHJAHAN; HYDER S.

    2006-01-01

    Density, viscosity, and refractive index, for glycine, DL-alanine, L-serine and DL-valine have been determined in aqueous solution of 0.05 mol/kg caffeine as a function of amino acid (AA) concentration at 25, 30, 35, and 40 ℃.The density data have been used to compute apparent molar volume. The partial molar volume (limiting apparent molar volume) was obtained by applying the Masson's equation. The viscosity data have been analyzed by means of Jones-Dole equation. The values of Falkenhagen coefficient and Jones-Dole coefficient thus obtained are used to interpret the solute-solute and solute-solvent interactions, respectively. Hydration number was also computed. The transition-state theory was applied to obtain the activation parameters of viscous flow, I.e., free energy of activation per mole of solvent, and solute. The enthalpy and entropy of activation of viscous flow were computed for the system. Refractive index was used to calculate molar refractivity of the mixtures. The results have been interpreted in the lightof various interactions occurring between the components of the mixtures under applied experimental conditions.

  6. Hydrogen exchange at the β-carbon of amino acids during transamination

    International Nuclear Information System (INIS)

    The hydrogen exchange at the β-carbon of L-alanine, L-glutamate and L-aspartate with water has been examined during transamination catalyzed by glutamic-oxaloacetic transaminase and by glutamic-pyruvic transaminase. A significant hydrogen exchange at the β-carbon has been demonstrated during incubation of L-[3-3H] alanine + glutamic-pyruvic transaminase, L-[3-3H] alanine + α-oxoglutarate + glutamic-pyruvic transaminase, L-[3-3H] glutamate + glutamic-oxaloacetic transaminase, L-[3-3H] glutamate + oxalocetate + glutamic-oxaloacetic transaminase, and L-[3-3H] glutamate + pyruvate + glutamic-pyruvic transaminase as shown by the appearance of 3H2O. No hydrogen exchange at the β-carbon of L-glutamate occurred during incubation of L-[3-3H] -glutamate with glutamic-pyruvic transaminase alone. The hydogen exchange at the β-carbon of L-glutamate coincides with transamination as demonstrated by nuclear magnetic resonance studies of 2H2O-L-glutamate exchange during transamination by glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase. No hydrogen exchange at the β-carbon occurred during transamination of L-aspartate by glutamic-oxaloacetic transaminase as shown by nuclear magnetic resonance spectroscopy. The results are discussed with special reference to the different equilibria between the pyridoxal form and the pyridoxamine form of glutamic-oxaloacetic transaminase and of glutamic-pyruvic transaminase. (orig.)

  7. Study on the EPR/dosimetric properties of some substituted alanines

    International Nuclear Information System (INIS)

    Polycrystalline phenyl-alanine and perdeuterated l-α-alanine (l-α-alanine-d4) were studied as potential high-energy radiation-sensitive materials (RSM) for solid state/EPR dosimetry. It was found that phenyl-alanine exhibits a linear dose response in the dose region 0.1-17kGy. However, phenyl-alanine is about 10 times less sensitive to γ-irradiation than standard l-α-alanine irradiated at the same doses. Moreover, the EPR response from phenyl-alanine is unstable and, independent of the absorbed dose, decreases by about 50% within 20 days after irradiation upon storage at room temperature. γ-irradiated polycrystalline perdeuterated l-α-alanine (CD3CD(NH2)COOH) has not previously been studied at room temperature by EPR spectroscopy. The first part of the present analysis was with respect to the structure of the EPR spectrum. By spectrum simulations, the presence of at least two radiation induced free radicals, R1=CH3C*(H)COOH and R2=H3N+-C*(CH3)COO-, was confirmed very clearly. Both these radicals were suggested previously from EPR and ENDOR studies of standard alanine crystals. The further investigations into the potential use of alanine-d4 as RSM, after choosing optimal EPR spectrometer settings parameters for this purpose, show that it is ca. two times more sensitive than standard l-α-alanine

  8. Transmembrane dynamics of the Thr-5 phosphorylated sarcolipin pentameric channel.

    Science.gov (United States)

    Cao, Yipeng; Wu, Xue; Wang, Xinyu; Sun, Haiying; Lee, Imshik

    2016-08-15

    Sarcolipin (SLN), an important membrane protein expressed in the sarcoplasmic reticulum (SR), regulates muscle contractions in cardiac and skeletal muscle. The phosphorylation at amino acid Thr5 of the SLN protein modulates the amount of Ca(2+) that passes through the SR. Using molecular dynamics simulation, we evaluated the phosphorylation at Thr5 of pentameric SLN (phospho-SLN) channel's energy barrier and pore characteristics by calculating the potential of mean force (PMF) along the channel pore and determining the diffusion coefficient. The results indicate that pentameric phospho-SLN promotes penetration of monovalent and divalent ions through the channel. The analysis of PMF, pore radius and diffusion coefficient indicates that Leu21 is the hydrophobic gate of the pentameric SLN channel. In the channel, water molecules near the Leu21 pore demonstrated a clear hydrated-dehydrated transition; however, the mutation of Leu21 to an Alanine (L21A) destroyed the hydrated-dehydrated transitions. These water-dynamic behaviors and PMF confirm that Leu21 is the key residue that regulates the ion permeability of the pentameric SLN channel. These results provide the structural-basis insights and molecular-dynamic information that are needed to understand the regulatory mechanisms of ion permeability in the pentameric SLN channel. PMID:27378083

  9. Synthesis and characterization of tin(II) complexes of fluorinated Schiff bases derived from amino acids

    Science.gov (United States)

    Singh, Har Lal

    2010-07-01

    New tin(II) complexes of general formula Sn(L) 2 (L = monoanion of 3-methyl-4-fluoro-acetophenone phenylalanine L 1H, 3-methyl-4-fluoro-acetophenone alanine L 2H, 3-methyl-4-fluoro acetophenone tryptophan L 3H, 3-methyl-4-fluoro-acetophenone valine L 4H, 3-methyl-4-fluoro-acetophenone isoleucine L 5H and 3-methyl-4-fluoro-acetophenone glycine L 6H) have been prepared. It is characterized by elemental analyses, molar conductance measurements and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance ( 1H, 13C, 19F and 119Sn NMR) spectral studies. The ligands act as bidentate towards metal ions, via the azomethine nitrogen and deprotonated oxygen of the respective amino acid. Elemental analyses and NMR spectral data of the ligands with their tin(II) complexes agree with their proposed square pyramidal structures. A few representative ligands and their tin complexes have been screened for their antibacterial activities and found to be quite active in this respect.

  10. Interactions of neurotoxins with non-NMDA glutamate receptors: an autoradiographic study

    International Nuclear Information System (INIS)

    Neurotoxic substances are discussed to cause neurode-generation by acting as excitotoxins on glutamate receptors. We investigated the properties of L-beta-oxalyl-amino-alanine (L-BOAA) and 3,4,6-trihydroxyphenlyalanine (6-OH-Dopa) at the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) glutamate receptor and that of L-BOAA and domoic acid at the kainate glutamate receptor in human hippocampus. (3 H)AMPA binding in hippocampal subfields was inhibited by L-BOAA and 6-OH-Dopa with mean IC50-values in the low micromolar range. (3H)Kainate binding was inhibited by L-BOAA with similar potency as (3H)AMPA binding and by domoic acid with mean IC50-values in the low nanomolar range. These results support the notion that symptoms like anterograde amnesia and epileptic seizures seen in domoic acid intoxication and limbic symptoms, e.g. cognitive and mood impairment observed in neurolathyrism may be caused by excitotoxic action on non-NMDA receptors. The potent interaction of 6-OH-Dopa with the AMPA-receptor may point to a possible dopaminergic-glutamatergic interaction in the development of neurodegenerative diseases like Parkinson's and Huntington's disease. (author)

  11. Assessing the effect of surface modification of polyamide RO membrane by l-DOPA on the short range physiochemical interactions with biopolymer fouling on the membrane.

    Science.gov (United States)

    Azari, Sara; Zou, Linda; Cornelissen, Emile

    2014-08-01

    Theoretical predictions of interaction energies for membrane-biopolymer foulant pairs were used to compare the fouling tendencies of a virgin commercial polyamide reverse osmosis (RO) membrane with a amino acid 3-(3,4-dihydroxyphenyl)-l-alanine (l-DOPA) coated RO membrane. Lifshitz-van der Waals (LW) and Lewis acid-base (AB) surface tension components of the membranes were determined based on contact angle results using the van Oss approach. From these values, the LW and AB components of the free energy of adhesion between membrane and foulants were calculated. Electrostatic (EL) double layer interaction energies between the membrane and foulants were also estimated using the measured surface charge data of the membranes and fouling agents. Bovine serum albumin (BSA) and alginic acid sodium salt (alginate) were used as model biopolymers causing membrane fouling. Based on the calculated adhesion free energies, acid-base interactions were found to have the strongest impact on the adhesion of both BSA and alginate to the either membranes surfaces. It was found that l-DOPA modification has significantly lowered acid-base interaction affinity toward the adhesion of both foulants studied. On the basis of calculated free energies of adhesion, lower fouling tendency of the l-DOPA modified membrane was expected. The accelerated fouling tests indicated a lower flux decline rate for the modified membrane and confirmed the results obtained from theory. PMID:24916284

  12. Effect of β-N-methylamino-L-alanine on oxidative stress of liver and kidney in rat.

    Science.gov (United States)

    de Munck, Estefanía; Muñoz-Sáez, Emma; Antonio, María Teresa; Pineda, Javier; Herrera, Amparo; Miguel, Begoña G; Arahuetes, Rosa María

    2013-03-01

    β-N-methylamino-(L)-alanine (L)-BMAA) is a neurotoxic amino acid, found in the majority of cyanbacterial genera tested. Evidence for implication of (L)-BMAA in neurodegenerative disorders, like amyotrophic lateral sclerosis (ALS), relies on bioaccumulation and biomagnification from symbiotic cyanobacteria. The involvement of (L)-BMAA in oxidative stress was demonstrated in several studies in the central nervous system. In the present study, we investigated the effect of (L)-BMAA on the oxidative stress responses of liver and kidney in rats treated by intraperitoneal administration with this amino acid. Oxidative stress was demonstrated by the quantification of lipid peroxidation, the measurement of both catalase and glutathione peroxidase activities, as well as the quantification of glutathione (GSH) levels and the total antioxidant capacity. It was observed that (L)-BMAA caused a significant increase in the degree of lipid peroxidation and catalase activity in both organs. A significant increase in glutathione peroxidase activity was obtained only in liver, whereas glutathione levels were also increased in both organs. The total antioxidant capacity decreased in liver and increased in kidney. These results suggest that the oxidative stress was higher in liver than in kidney, and might be crucial for (L)-BMAA toxicological action. PMID:23328118

  13. Animal models of brain maldevelopment induced by cycad plant genotoxins.

    Science.gov (United States)

    Kisby, Glen E; Moore, Holly; Spencer, Peter S

    2013-12-01

    Cycads are long-lived tropical and subtropical plants that contain azoxyglycosides (e.g., cycasin, macrozamin) and neurotoxic amino acids (notably β-N-methylamino-l-alanine l-BMAA), toxins that have been implicated in the etiology of a disappearing neurodegenerative disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex that has been present in high incidence among three genetically distinct populations in the western Pacific. The neuropathology of amyotrophic lateral sclerosis/parkinsonism-dementia complex includes features suggestive of brain maldevelopment, an experimentally proven property of cycasin attributable to the genotoxic action of its aglycone methylazoxymethanol (MAM). This property of MAM has been exploited by neurobiologists as a tool to study perturbations of brain development. Depending on the neurodevelopmental stage, MAM can induce features in laboratory animals that model certain characteristics of epilepsy, schizophrenia, or ataxia. Studies in DNA repair-deficient mice show that MAM perturbs brain development through a DNA damage-mediated mechanism. The brain DNA lesions produced by systemic MAM appear to modulate the expression of genes that regulate neurodevelopment and contribute to neurodegeneration. Epigenetic changes (histone lysine methylation) have also been detected in the underdeveloped brain after MAM administration. The DNA damage and epigenetic changes produced by MAM and, perhaps by chemically related substances (e.g., nitrosamines, nitrosoureas, hydrazines), might be an important mechanism by which early-life exposure to genotoxicants can induce long-term brain dysfunction. PMID:24339036

  14. Identification of a Vibrio cholerae chemoreceptor that senses taurine and amino acids as attractants

    Science.gov (United States)

    Nishiyama, So-ichiro; Takahashi, Yohei; Yamamoto, Kentaro; Suzuki, Daisuke; Itoh, Yasuaki; Sumita, Kazumasa; Uchida, Yumiko; Homma, Michio; Imada, Katsumi; Kawagishi, Ikuro

    2016-01-01

    Vibrio cholerae, the etiological agent of cholera, was found to be attracted by taurine (2-aminoethanesulfonic acid), a major constituent of human bile. Mlp37, the closest homolog of the previously identified amino acid chemoreceptor Mlp24, was found to mediate taxis to taurine as well as L-serine, L-alanine, L-arginine, and other amino acids. Methylation of Mlp37 was enhanced upon the addition of taurine and amino acids. Isothermal titration calorimetry demonstrated that a purified periplasmic fragment of Mlp37 binds directly to taurine, L-serine, L-alanine and L-arginine. Crystal structures of the periplamic domain of Mlp37 revealed that L-serine and taurine bind to the membrane-distal PAS domain in essentially in the same way. The structural information was supported by characterising the in vivo properties of alanine-substituted mutant forms of Mlp37. The fact that the ligand-binding domain of the L-serine complex had a small opening, which would accommodate a larger R group, accounts for the broad ligand specificity of Mlp37 and allowed us to visualise ligand binding to Mlp37 with fluorescently labelled L-serine. Taken together, we conclude that Mlp37 serves as the major chemoreceptor for taurine and various amino acids. PMID:26878914

  15. The formation of amino acid and dipeptide complexes with α-cyclodextrin and cucurbit[6]uril in aqueous solutions studied by titration calorimetry

    International Nuclear Information System (INIS)

    The complex stabilities and the thermodynamic data for the complexation of α-cyclodextrin and cucurbit[6]uril with some amino acids (glycine, L-alanine, L-valine, L-phenylalanine, 6-amino hexanoic acid, 8-amino octanoic acid, 11-amino undecanoic acid) and dipeptides (glycyl-glycine, glycyl-L-valine, glycyl-L-leucine and glycyl-L-phenylalanine) have been determined in aqueous solution by calorimetric titrations. The complex formation with α-cyclodextrin is mainly favoured by entropic contributions due to the release of water molecules from the cavity of the ligand. The values of the reaction enthalpies are small with the exception of 11-amino undecanoic acid. In case of the ligand cucurbit[6]uril, ion-dipole interactions between the protonated amino groups of the amino acids and the carbonyl groups take place. By steric reasons these interactions are lowered for native amino acids because the polar carboxylic groups are always located outside the hydrophobic cavity of cucurbit[6]uril. The complexes of both ligands with dipeptides in water are characterised by hydrophobic interactions and in case of cucurbit[6]uril by additional ion-dipole interactions

  16. Synthesis, characterization and pharmacological evaluation of amide prodrugs of Flurbiprofen

    International Nuclear Information System (INIS)

    Flurbiprofen (FB) suffers from the general side effects of NSAIDs, owing to presence of free carboxylic acid group. The study was aimed to retard the adverse effects of gastrointestinal origin. Ten prodrugs of FB were synthesized by amidation with ethyl esters of amino acids, namely, glycine, L-phenylalanine, L-tryptophan, L-valine, L-isoleucine, L-alanine, L-leucine, L-glutamic acid, L-aspartic acid and β alanine. Purified synthesized prodrugs were characterized by m.p., TLC, solubility, partition coefficients, elemental analyses, UV, FTIR, NMR and MS. Synthesized prodrugs were subjected for bioavailability studies, analgesic, anti-inflammatory activities and ulcerogenic index. Marked reduction of ulcerogenic index and comparable analgesic, antiinflammatory activities were obtained in all cases as compared to FB. Among synthesized prodrugs AR-9, AR-10 and AR-2 showing excellent pharmacological response and encouraging hydrolysis rate both in (Simulated Intestinal Fluid) SIF and in 80% human plasma. Prodrugs with increased aliphatic side chain length or introduction of aromatic substituent resulted in enhanced partition coefficient but diminished dissolution and hydrolysis rate. Such prodrugs can be considered for sustained release purpose. (author)

  17. Enantiomeric pair of copper(II) polypyridyl-alanine complexes: Effect of chirality on their interaction with biomolecules.

    Science.gov (United States)

    Ng, Chew Hee; Chan, Cheang Wei; Lai, Jing Wei; Ooi, Ing Hong; Chong, Kok Vei; Maah, Mohd Jamil; Seng, Hoi Ling

    2016-07-01

    Like chiral organic drugs, the chemical and biological properties of metal complexes can be dependent on chirality. Two pairs of [Cu(phen)(ala)(H2O)]X·xH2O (phen=1.10-phenanthroline: X=NO3(-); ala: l-alanine (l-ala), 1 and d-alanine (d-ala) 2; and (X=Cl(-); ala: l-ala, 3 and d-ala, 4) complex salts (x=number of lattice water molecules) have been synthesized and characterized. The crystal structure of 3 has been determined. The same pair of enantiomeric species, viz. [Cu(phen)(l-ala)(H2O)](+) and [Cu(phen)(d-ala)(H2O)](+), have been identified to be present in the aqueous solutions of both 1 and 3, and in those of both 2 and 4 respectively. Both 3 and 4 bind more strongly to ds(AT)6 than ds(CG)6. There is no or insignificant effect of the chirality of 3 and 4 on the production of hydroxyl radicals, binding to deoxyribonucleic acid from calf thymus (CT-DNA), ds(CG)6, G-quadruplex and 17-base pair duplex, and inhibition of both topoisomerase I and proteasome. Among the three proteasome proteolytic sites, the trypsin-like site is inhibited most strongly by these complexes. However, the chirality of 3 and 4 does affect the number of restriction enzymes inhibited, and their binding constants towards ds(AT)6 and serum albumin. PMID:27105312

  18. Important role of fungal intracellular laccase for melanin synthesis: purification and characterization of an intracellular laccase from Lentinula edodes fruit bodies.

    Science.gov (United States)

    Nagai, Masaru; Kawata, Maki; Watanabe, Hisayuki; Ogawa, Machiko; Saito, Kumiko; Takesawa, Toshikazu; Kanda, Katsuhiro; Sato, Toshitsugu

    2003-09-01

    A laccase (EC 1.10.3.2) was isolated from the fully browned gills of Lentinula edodes fruit bodies. The enzyme was purified to a homogeneous preparation using hydrophobic, cation-exchange and size-exclusion chromatography. SDS-PAGE analysis showed the purified laccase, Lcc 2, to be a monomeric protein of 58.0 kDa. The enzyme had an isoelectric point of around pH 6.9. The optimum pH for enzyme activity was around 3.0 against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS), and it was most active at 40 degrees C and stable up to 50 degrees C. The enzyme contained 8.6 % carbohydrate and some copper atoms. The enzyme oxidized ABTS, p-phenylenediamine, pyrogallol, guaiacol, 2,6-dimethoxyphenol, catechol and ferulic acid, but not veratryl alcohol and tyrosine. Beta-(3,4-dihydroxyphenyl)alanine (L-DOPA), which was not oxidized by a laccase previously reported from the culture filtrate of L. edodes, was also oxidized by Lcc 2, and the oxidative product of L-dopa was identified as L-DOPA quinone by HPLC analysis. Lcc 2 was able to oxidize phenolic compounds extracted from fresh gills to brown-coloured products, suggesting a role for laccase in melanin synthesis in this strain. PMID:12949171

  19. Purification and characterization of a highly stable tyrosinase from Thermomicrobium roseum.

    Science.gov (United States)

    Kong, K H; Hong, M P; Choi, S S; Kim, Y T; Cho, S H

    2000-04-01

    Tyrosinase, with an isoelectric point at pH 4.9, was purified to electrophoretic homogeneity from an extremely thermophilic bacterium, Thermomicrobium roseum. Gel filtration, N-terminal amino acid sequencing and SDS/PAGE analysis indicate that T. roseum tyrosinase is composed of two identical subunits, each with a molecular mass of 43000 Da. The enzyme exhibited high substrate specificity towards catechol, chlorogenic acid, L-3-(3,4-dihydroxyphenyl)-L-alanine (L-DOPA) and pyrogallol. The K(m) value of the enzyme for L-DOPA was 0.18 mM. beta-Mercaptoethanol and sodium diethyldithiocarbamate notably inhibited the enzymic activity. The activity of the enzyme was optimal at pH 9.5 and 70 degrees C, and was increased by addition of 1 mM Mg(2+), K(+) or Cu(2+). The enzyme was highly stable against high temperature and guanidine hydrochloride. The N-terminal amino acid sequence of the enzyme was determined to be Asp-Ile-Asn-Gly-Gly-Gly-Ala-Thr-Leu-Pro-Gln-Lys-Leu-Tyr. These facts indicate that T. roseum tyrosinase appears to be distinct from the tyrosinases so far purified from other sources. PMID:10744956

  20. Application of the spin-trap HPLC-ESR method to radiation chemistry of amino acids in aqueous solutions. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Makino, K.; Moriya, F.; Hatano, H. (Kyoto Univ. (Japan). Faculty of Science)

    1984-01-01

    Our recent studies of the application of the newly developed spin-trap HPLC-ESR method to ..gamma..-radiolysis of aqueous solutions containing amino acids are reviewed. 2-Methyl-2-nitrosopropane (MNP) was used as a spin trap to convert generated unstable free radicals into relatively stable aminoxyl radicals, which were separated individually by HPLC with cation-exchange columns. Compounds derived from MNP during the preparation of aqueous MNP solutions were found to be t-butylnitrosohydroxylamine, t-butyl alcohol and isobutene. The preparation procedure of the solution in which these undesirable products are minimized is proposed. ..gamma..-Radiolysis of aqueous MNP solutions resulted in the formation of five aminoxyl radicals. The chromatographic retention times of the radicals were found to be different from those of the spin adducts from the amino acids studied here. Amino acids investigated in the present work were glycine, L-alanine, L-valine, L-isoleucine, L-leucine and DL-methionine. Twenty-five spin adducts from the amino acids were detected and identified by the method. The reactions by which short-lived radicals are produced in ..gamma..-irradiated aqueous solutions of the amino acids have been found to be H-abstraction by hydroxyl radicals and deamination by hydrated electrons.

  1. Tritium suicide selection of mammalian cell mutants defective in the transport of neutral amino acids

    International Nuclear Information System (INIS)

    Mouse lymphocytic cells of the established line GF-14 were allowed to accumulate intracellular 3H-labeled aminoisobutyric acid (AIB), frozen and stored over liquid N2. After internal radiation had reduced survival to 1 in 104, survivors were plated and tested for their ability to transport AIB. Out of 200 clones tested, two (designated GF-17 and GF-18) were found to have reductions to 13 to 35% of the parent in the rate of transport of AIB, L-alanine, L-proline, and L-serine; GF-18 also showed significant reductions in the rate of transport of L-glutamate and DL-cysteine. Little or no change was observed for 10 other amino acids or for thymidine. Kinetic analyses revealed that the mutants were not altered in K/sub m/ for AIB uptake, but had V/sub max/ values approximately 20% the value of the parent strain, GF-14, suggesting that either the number of AIB transport sites or the turnover rate of the sites has been reduced in the two mutants

  2. Electrocatalytic oxidation of some amino acids on a nickel-curcumin complex modified glassy carbon electrode

    International Nuclear Information System (INIS)

    This study investigated the electrocatalytic oxidation of alanine, L-arginine, L-phenylalanine, L-lysine and glycine on poly-Ni(II)-curcumin film (curcumin: 1,7-bis [4-hydroxy-3-methoxy phenyl]-1,6-heptadiene-3,5-dione) electrodeposited on a glassy carbon electrode in alkaline solution. The process of oxidation and its kinetics were established by using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques. Voltammetric studies indicated that in the presence of amino acids the anodic peak current of low valence nickel species increased, followed by a decrease in the corresponding cathodic current. This indicates that amino acids were oxidized on the redox mediator which was immobilized on the electrode surface via an electrocatalytic mechanism. Using Laviron's equation, the values of α and k s for the immobilized redox species were determined as 0.43 ± 0.03 and 2.47 ± 0.02 x 106 s-1, respectively. The rate constant, the electron transfer coefficient and the diffusion coefficients involved in the electrocatalytic oxidation of amino acids were determined

  3. Structure of the Mycobacterium tuberculosis proteasome and mechanism of inhibition by a peptidyl boronate.

    Science.gov (United States)

    Hu, Guiqing; Lin, Gang; Wang, Ming; Dick, Lawrence; Xu, Rui-Ming; Nathan, Carl; Li, Huilin

    2006-03-01

    Mycobacterium tuberculosis (Mtb) has the remarkable ability to resist killing by human macrophages. The 750 kDa proteasome, not available in most eubacteria except Actinomycetes, appears to contribute to Mtb's resistance. The crystal structure of the Mtb proteasome at 3.0 A resolution reveals a substrate-binding pocket with composite features of the distinct beta1, beta2 and beta5 substrate binding sites of eukaryotic proteasomes, accounting for the broad specificity of the Mtb proteasome towards oligopeptides described in the companion article [Lin et al. (2006), Mol Microbiol doi:10.1111/j.1365-2958.2005.05035.x]. The substrate entrance at the end of the cylindrical proteasome appears open in the crystal structure due to partial disorder of the alpha-subunit N-terminal residues. However, cryo-electron microscopy of the core particle reveals a closed end, compatible with the density observed in negative-staining electron microscopy that depended on the presence of the N-terminal octapetides of the alpha-subunits in the companion article, suggesting that the Mtb proteasome has a gated structure. We determine for the first time the proteasomal inhibition mechanism of the dipeptidyl boronate N-(4-morpholine)carbonyl-beta-(1-naphthyl)-L-alanine-L-leucine boronic acid (MLN-273), an analogue of the antimyeloma drug bortezomib. The structure improves prospects for designing Mtb-specific proteasomal inhibitors as a novel approach to chemotherapy of tuberculosis. PMID:16468986

  4. Structure of the Mycobacterium tuberculosis proteasome and mechanism of inhibition by a peptidyl boronate

    Energy Technology Data Exchange (ETDEWEB)

    Hu,G.; Lin, G.; Wang, M.; Dick, L.; Xu, R.; Nathan, C.; Li, H.

    2006-01-01

    Mycobacterium tuberculosis (Mtb) has the remarkable ability to resist killing by human macrophages. The 750 kDa proteasome, not available in most eubacteria except Actinomycetes, appears to contribute to Mtb's resistance. The crystal structure of the Mtb proteasome at 3.0 Angstroms resolution reveals a substrate-binding pocket with composite features of the distinct {beta}1, {beta}2 and {beta}5 substrate binding sites of eukaryotic proteasomes, accounting for the broad specificity of the Mtb proteasome towards oligopeptides described in the companion article [Lin et al. (2006), Mol Microbiol doi:10.1111/j.1365-2958.2005.05035.x]. The substrate entrance at the end of the cylindrical proteasome appears open in the crystal structure due to partial disorder of the a-subunit N-terminal residues. However, cryo-electron microscopy of the core particle reveals a closed end, compatible with the density observed in negative-staining electron microscopy that depended on the presence of the N-terminal octapeptides of the a-subunits in the companion article, suggesting that the Mtb proteasome has a gated structure. We determine for the first time the proteasomal inhibition mechanism of the dipeptidyl boronate N-(4-morpholine)carbonyl-{beta}-(1-naphthyl)-l-alanine-l-leucine boronic acid (MLN-273), an analogue of the antimyeloma drug bortezomib. The structure improves prospects for designing Mtb-specific proteasomal inhibitors as a novel approach to chemotherapy of tuberculosis.

  5. Influence of different cultural conditions on cellulase production by Nectria catalinensis.

    Science.gov (United States)

    Pardo, A G; Forchiassin, F

    1998-01-01

    The production of the extracellular cellulolytic enzyme system (endoglucanase, exoglucanase and cellobiase) of N. catalinensis was tested with different nitrogen sources, inorganic and organic ones, in liquid culture medium with microcrystalline cellulose. The nitrogen compounds used were: potassium nitrate, sodium nitrate, ammonium nitrate, ammonium phosphate, ammonium sulphate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium tartrate, urea, casamino acids, glycine, L-alanine, L-leucine, L-proline, L-lysine, L-aspartic acid, L-glutamic acid, L-asparagine, L-glutamine, L-phenylalanine, L-tyrosine, L-tryptophan, L-methionine and L-cysteine. Among these, ammonium nitrate and ammonium tartrate gave the highest yields of cellulases in 20-day-old cultures at a concentration equivalent to 0.75 g N/l in both cases. Optimal temperature for cellulase production, growth and cellulose degradation was 23 degrees C. On the other hand, an initial pH of 6.5 gave the highest yields of endoglucanase and cellobiase. In the same way, at pH 6.5, maximal growth and cellulose degradation were achieved. However, maximal exoglucanase production and glycogen content were reached at pH 7.5. PMID:9629604

  6. Effects of the Biomolecules: Vitamins, Proteins, Amino Acids, and Surfactants: DTAB, MTOAC, TMSOI, Orcinol on Upper Critical Solution Temperatures

    Directory of Open Access Journals (Sweden)

    Vinod Kumar

    2007-09-01

    Full Text Available Upper critical solution temperatures (UCSTS ± 0.05 K and mutual solubilities of phenol + water systems are reported separately with 0.5 millimol kg-1 (mm kg-1 proteins (casein, pepsin, egg-albumin, vitamins (B1-thiamine, B2-riboflavin, B6-pyridoxine, amino acids (glycine, β-alanine, L-leucine and surfactants (dodecyl trimethylammonium bromide- DTAB, trimethylsulphoxonium iodide-TMSOI, methyltrioctylammonium chloride- MTOAC, orcinol. The additives decrease the UCSTs by about 0.50-2 0C with slight enhancement in mutual solubilities but the leucine with two –CH3 (methyl and two - CH2- (methylene groups produce negligible increase in the solubilities. The –CH3 and - CH2- groups develop stronger hydrophobic interactions but the glycine develops stronger hydrophilic interactions due to –N+H3 (amino and –COO- (carboxylic groups and weaker hydrophobic due to single –CH2- group. The leucine increases the solubility by 0.009 mole fractions with a 0.7 0C decrease in USCT as compared to phenol-water. The mole fractions of additives restricted to 0.002 to 0.005 range, the conjugations of casein and vitamins in place of –CH3 groups of amino acids enhance the solubility with lower UCST values.

  7. Studies on Partial Molar Volumes of Some Amino Acids and Their Groups in Aqueous Solutions from 293.15 K to 333.15 K

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 马沛生; 夏淑倩

    2004-01-01

    Abstract Densities of aqueous solutions of eight amino acids, glycine, L-alanine, L-valine, L-isoleucine, L-serine, L-threonine, L-arginine and L-phenylalanine, are measured as a function of amino acid concentration from 293.15 K to 333.15 K. These data are used to calculate the apparent molar volume Vφ0 and infinite dilution apparent molar volume Vφ0 (partial molar volume). Data of five amino acids are used to correlate partial molar volume Vφ0 using group contribution method to estimate the contributions of the zwitterionic end groups (NH+,COO-) and CH2 group, OH group, CNHNHNH2 group and C6H5(phenyl) group of amino acids. The results show that Vφ0 values for all kinds of groups of amino acids studied increase with increase of temperature except those for CH2φ group, which are almost constant within the studied temperature range. Data of other amino acids, L-valine, L-isoleucine and L-threonine, are chosen for comparison with the predicted partial molar volume Vφ0 using the group additivity parameters obtained. The results confirm that this group additivity method has excellent predictive utility.

  8. 293.15 K到333.15 K温度下一些氨基酸及其相应基团水溶液中的偏摩尔体积研究%Studies on Partial Molar Volumes of Some Amino Acids and Their Groups in Aqueous Solutions from 293.15 K to 333.15 K

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 马沛生; 夏淑倩

    2004-01-01

    Densities of aqueous solutions of eight amino acids, glycine, L-alanine, L-valine, L-isoleucine, L-serine,L-threonine, L-arginine and L-phenylalanine, are measured as a function of amino acid concentration from 293.15 K to 333.15K. These data are used to calculate the apparent molar volume V and infinite dilution apparent molar volume V0 (partial molar volume). Data of five amino acids are used to correlate partial molar volume V0 using group contribution method to estimate the contributions of the zwitterionic end groups (NH3+,COO-) and CH2group, OH group, CNHNHNH2 group and C6H5(phenyl) group of amino acids. The results show that V0 values for all kinds of groups of amino acids studied increase with increase of temperature except those for CH2 group,which are almost constant within the studied temperature range. Data of other amino acids, L-valine, L-isoleucine and L-threonine, are chosen for comparison with the predicted partial molar volume V0 using the group additivity parameters obtained. The results confirm that this group additivity method has excellent predictive utility.

  9. Influence of the composition of aqueous-alcohol solvents on the thermodynamic characteristics of L-phenylalanine dissolution at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Badelin, Valentin G. [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Street, 153045, Ivanovo (Russian Federation); Smirnov, Valeriy I., E-mail: vis@isc-ras.ru [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Street, 153045, Ivanovo (Russian Federation)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Enthalpies of L-phenylalanine dissolution have been measured in aqueous methanol, ethanol, 1-propanol and 2-propanol. Black-Right-Pointing-Pointer The measured data were reported as functions of composition of water + alcohol mixtures. Black-Right-Pointing-Pointer Enthalpy coefficients of pair-wise interactions have been analyzed in terms of McMillan-Mayer theory. Black-Right-Pointing-Pointer A comparative analysis of the characteristics of dissolution of L-phenylalanine and some other L-amino acids in the similar systems has been made. - Abstract: The enthalpies of L-phenylalanine dissolution in aqueous methanol, ethanol, 1-propanol and 2-propanol have been determined by calorimetry at 298.15 K and alcohol mole fractions up to x{sub 2} {approx}0.4. The standard enthalpies of solution {Delta}{sub sol}H Degree-Sign and transfer {Delta}{sub tr}H Degree-Sign from water to the mixed solvent as well as the enthalpy coefficients of L-phenylalanine-alcohol pair-wise interactions were calculated. The interrelation of the enthalpies of dissolution and transfer for L-phenylalanine with structural features of alcohols has been determined. A comparative analysis of the thermodynamic characteristics of dissolution of L-phenylalanine and some other amino acids (glycine, L-alanine, L-threonine and L-valine) in the mixtures studied has been made.

  10. Volumetric behaviour of amino acids and their group contributions in aqueous lactose solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Amalendu, E-mail: palchem@sify.co [Department of Chemistry, Kurukshetra University, Kurukshetra 136 119 (India); Chauhan, Nalin [Department of Chemistry, Kurukshetra University, Kurukshetra 136 119 (India)

    2011-02-15

    Densities, {rho}, for glycine, L-alanine, L-valine, and L-leucine [(0.05 to 0.30) m] in aqueous lactose solutions ranging from pure water to 6 mass% lactose were determined at T = (293.15, 298.15, 303.15, and 308.15) K. The density was used to compute apparent molar volume, V{sub {phi}}, partial molar volume at infinite dilution, V{sub {phi}}{sup o}, and experimental slope, S{sub V} were obtained and interpreted in terms of solute-solvent and solute-solute interactions. These data were used to calculate the ({partial_derivative}V{sub {phi}}{sup 0}/{partial_derivative}T){sub P} values. The partial molar volume of transfer, {Delta}V{sub {phi}}{sup 0} from water to aqueous lactose solutions at infinite dilution has also been calculated. In addition to this, the linear correlation of V{sub {phi}}{sup 0} with number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of NH{sub 3}{sup +}COO{sup -}, and CH{sub 2} groups to V{sub {phi}}{sup 0}.

  11. Synthesis, characterization and pharmacological evaluation of amide prodrugs of Flurbiprofen

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Ashutosh; Veerasamy, Ravichandran; Jain, Prateek Kumar; Dixit, Vinod Kumar; Agrawal, Ram Kishor [Dr. H. S. Gour Vishwavidyalaya, Sagar (India). Dept. of Pharmaceutical Sciences. Pharmaceutical Chemistry Research Lab.]. E-mail: dragrawal2001@yahoo.co.in

    2008-07-01

    Flurbiprofen (FB) suffers from the general side effects of NSAIDs, owing to presence of free carboxylic acid group. The study was aimed to retard the adverse effects of gastrointestinal origin. Ten prodrugs of FB were synthesized by amidation with ethyl esters of amino acids, namely, glycine, L-phenylalanine, L-tryptophan, L-valine, L-isoleucine, L-alanine, L-leucine, L-glutamic acid, L-aspartic acid and {beta} alanine. Purified synthesized prodrugs were characterized by m.p., TLC, solubility, partition coefficients, elemental analyses, UV, FTIR, NMR and MS. Synthesized prodrugs were subjected for bioavailability studies, analgesic, anti-inflammatory activities and ulcerogenic index. Marked reduction of ulcerogenic index and comparable analgesic, antiinflammatory activities were obtained in all cases as compared to FB. Among synthesized prodrugs AR-9, AR-10 and AR-2 showing excellent pharmacological response and encouraging hydrolysis rate both in (Simulated Intestinal Fluid) SIF and in 80% human plasma. Prodrugs with increased aliphatic side chain length or introduction of aromatic substituent resulted in enhanced partition coefficient but diminished dissolution and hydrolysis rate. Such prodrugs can be considered for sustained release purpose. (author)

  12. Simple enzymatic procedure for L-carnosine synthesis: whole-cell biocatalysis and efficient biocatalyst recycling.

    Science.gov (United States)

    Heyland, Jan; Antweiler, Nicolai; Lutz, Jochen; Heck, Tobias; Geueke, Birgit; Kohler, Hans-Peter E; Blank, Lars M; Schmid, Andreas

    2010-01-01

    β-Peptides and their derivates are usually stable to proteolysis and have an increased half-life compared with α-peptides. Recently, β-aminopeptidases were described as a new enzyme class that enabled the enzymatic degradation and formation of β-peptides. As an alternative to the existing chemical synthesis routes, the aim of the present work was to develop a whole-cell biocatalyst for the synthesis and production of β-peptides using this enzymatic activity. For the optimization of the reaction system we chose the commercially relevant β,α-dipeptide L-carnosine (β-alanine-L-histidine) as model product. We were able to show that different recombinant yeast and bacteria strains, which overexpress a β-peptidase, could be used directly as whole-cell biocatalysts for the synthesis of L-carnosine. By optimizing relevant reaction conditions for the best-performing recombinant Escherichia coli strain, such as pH and substrate concentrations, we obtained high l-carnosine yields of up to 71%. Long-time as well as biocatalyst recycling experiments indicated a high stability of the developed biocatalyst for at least five repeated batches. Application of the recombinant E. coli in a fed-batch process enabled the accumulation of l-carnosine to a concentration of 3.7 g l(-1). PMID:21255308

  13. Defining Multiple Characteristic Raman Bands of α-Amino Acids as Biomarkers for Planetary Missions Using a Statistical Method

    Science.gov (United States)

    Rolfe, S. M.; Patel, M. R.; Gilmour, I.; Olsson-Francis, K.; Ringrose, T. J.

    2016-06-01

    Biomarker molecules, such as amino acids, are key to discovering whether life exists elsewhere in the Solar System. Raman spectroscopy, a technique capable of detecting biomarkers, will be on board future planetary missions including the ExoMars rover. Generally, the position of the strongest band in the spectra of amino acids is reported as the identifying band. However, for an unknown sample, it is desirable to define multiple characteristic bands for molecules to avoid any ambiguous identification. To date, there has been no definition of multiple characteristic bands for amino acids of interest to astrobiology. This study examined l-alanine, l-aspartic acid, l-cysteine, l-glutamine and glycine and defined several Raman bands per molecule for reference as characteristic identifiers. Per amino acid, 240 spectra were recorded and compared using established statistical tests including ANOVA. The number of characteristic bands defined were 10, 12, 12, 14 and 19 for l-alanine (strongest intensity band: 832 cm-1), l-aspartic acid (938 cm-1), l-cysteine (679 cm-1), l-glutamine (1090 cm-1) and glycine (875 cm-1), respectively. The intensity of bands differed by up to six times when several points on the crystal sample were rotated through 360 °; to reduce this effect when defining characteristic bands for other molecules, we find that spectra should be recorded at a statistically significant number of points per sample to remove the effect of sample rotation. It is crucial that sets of characteristic Raman bands are defined for biomarkers that are targets for future planetary missions to ensure a positive identification can be made.

  14. Viscous and Surface Properties of Upper Critical Solution Temperatures of Immiscible Solvents with Biomolecules, Surfactants and Polymer Resin

    Directory of Open Access Journals (Sweden)

    Man Singh

    2011-05-01

    Full Text Available

    Viscosity and surface tension of upper critical solutions (UCS of water + phenol with ΔG > 0 are reported. The phenol upper critical solutions within before (B and after (A UCS temperatures range are depicted as BUCS and AUCS respectively and were used for study. Viscous flow times (t, sec and pendant drop numbers (n were measured together with Survismeter for h/N m s-2 and g/mN m-1 respectively. The t and n were repeated for UCS with 0.5 millimol/L proteins (casein, pepsin, EA-Egg, albumin, vitamins [thiamine (B1, riboflavin (B2, pyridoxine (B6], amino acids (glycine, b-alanine, L-leucine, surfactants dodecyltrimethylammoniumbromide (DTAB, trimethylsulphoxoniumiodide (TMSOI, methyltrioctylammoniumchloride (MTOAC, orcinol and melamineformaldehyde-polyvinylpyrrolidone (MFP. Additives formed UCS at lower temperature with about 60% thermal energy saving. The t and n were used to calculate tn sec-1 for density calculation with Mansingh equation. The BUCS, UCS and AUCS as pre UCS and post UCS were obtained at 600C, 700C and 610C respectively. The tn with water were obtained for 25 to 700C and plotted with corresponding densities (± 0.05 kg m-3 for calibration curve used for density calculations. The densities were noted as TMSOI > orcinol > MFP > DTAB > MTOAC, with lower values at 66.5 and higher at 660C.


  15. High performance microbiological transformation of L-tyrosine to L-dopa by Yarrowia lipolytica NRRL-143

    Directory of Open Access Journals (Sweden)

    Shultz Jeffry L

    2007-08-01

    Full Text Available Abstract Background The 3,4-dihydroxy phenyl L-alanine (L-dopa is a drug of choice for Parkinson's disease, controlling changes in energy metabolism enzymes of the myocardium following neurogenic injury. Aspergillus oryzae is commonly used for L-dopa production; however, potential improvements in ease of handling, growth rate and environmental impact have led to an interest in exploiting alternative yeasts. The two important elements required for L-dopa production are intracellular tyrosinases (thus pre-grown yeast cells are required for the transformation of L-tyrosine to L-dopa and L-ascorbate, which acts as a reducing agent. Results Pre-grown cells of Yarrowia lipolytica NRRL-143 were used for the microbiological transformation of L-tyrosine to L-dopa. Different diatomite concentrations (0.5–3.0 mg/ml were added to the acidic (pH 3.5 reaction mixture. Maximum L-dopa biosynthesis (2.96 mg/ml L-dopa from 2.68 mg/ml L-tyrosine was obtained when 2.0 mg/ml diatomite was added 15 min after the start of the reaction. After optimizing reaction time (30 min, and yeast cell concentration (2.5 mg/ml, an overall 12.5 fold higher L-dopa production rate was observed when compared to the control. Significant enhancements in Yp/s, Qs and qs over the control were observed. Conclusion Diatomite (2.0 mg/ml addition 15 min after reaction commencement improved microbiological transformation of L-tyrosine to L-dopa (3.48 mg/ml; p ≤ 0.05 by Y. lipolytica NRRL-143. A 35% higher substrate conversion rate was achieved when compared to the control.

  16. Highly sensitive interference-free electrochemical determination of pyridoxine at graphene modified electrode: Importance in Parkinson and Asthma treatments.

    Science.gov (United States)

    Raj, M Amal; Gowthaman, N S K; John, S Abraham

    2016-07-15

    To reduce the side effects in the medication of Parkinson and Asthma, pyridoxine (PY) is administered along with l-3,4-dihydroxyphenyl alanine (l-dopa) and theophylline (TP), respectively. However, excessive dosage of PY leads to nervous disorder. Thus, a sensitive and selective electrochemical method was developed for the determination of PY in the presence of major interferences including TP, l-dopa, ascorbic acid (AA) and riboflavin (RB) using electrochemically reduced graphene oxide (ERGO) film modified glassy carbon electrode (GCE) in this paper. The ERGO fabrication process involves the nucleophilic substitution of graphene oxide at basic pH on amine terminal of 1,6-hexadiamine which was pre-assembled on GCE followed by electrochemical reduction. The electrocatalytic activity of the ERGO modified electrode was examined towards the oxidation of PY. It greatly enhanced the oxidation current of PY in contrast to bare and GO modified GCEs due to facile electron transfer besides π-π interaction between ERGO film and PY. Since TP and l-dopa drugs antagonize the drug action of PY, ERGO modified GCE was also used for the simultaneous determination of PY and l-dopa and PY and TP. Further, the selective determination of PY in the presence of other water soluble vitamins such as ascorbic acid and riboflavin was also demonstrated. Using amperometry, detection of 100nM PY was achieved and the detection limit was found to be 5.6×10(-8)M (S/N=3). The practical application of the present method was demonstrated by determining the concentration of PY in human blood serum and commercial drugs. PMID:27124811

  17. 1-L-丙氨酸-1-脱氧-D-果糖的合成及在卷烟中的应用%Synthesis of 1-L-Alanine-1-deoxy-D-fructose and its Application in Cigarette

    Institute of Scientific and Technical Information of China (English)

    张敦铁; 肜霖; 黄龙; 朱魏; 熊国玺

    2012-01-01

    In order to further .study on MaiMard reaction, the synthesis of the Maillard reaction intermediate was studied in mixture of anhydrous methanol and glycerol system, using alamne and glucose; as raw materials. The Maillard reaction intermediate was received after separation and purification. The structure of purified product was identified by IR. MS, NMR and so on. The cigarette applied with simplex product was evaluated by experts of panel lest. The results showed that: the synthesed compound is the target product. It is 1-l.-alanine-l-deoxy-D-fructose( ADF), and its yield is 62.7%. The sensory evaluation showed that the ADF could enhance the aroma of smoke, reduce the offensive odor and improve the aflertaste.%为进一步研究Maillard反应,以丙氨酸、葡萄糖为原料,在甲醇甘油体系中加入一定催化剂进行反应,经分离纯化得到Maillard反应中间体,再运用IR、MS、NMR进行了结构表征,并将这一产物加入卷烟中进行评吸.结果表明:这一单一产物为目标化合物,即1-L-丙氨酸-1-脱氧D-果糖(ADF),其产率为62.7%;ADF在卷烟中具有增浓、增香、减少杂气、改善余味等作用,可以提高卷烟感官质量.

  18. Enolisation Kinetics of m-Nitro Acetophenone

    Directory of Open Access Journals (Sweden)

    Swati Malhotra

    2014-03-01

    Full Text Available m-Nitroacetophenone was chosen for the study of kinetics of enolisation. The rate of the reaction was studied by iodination. The kinetics of the reaction was monitored under several conditions of variation of ketone concentration, dielectric constant of the medium , temperature, effect of catalyst etc. In addition to this four different amino acids viz. β-alanin, DL-alanin, L-alanin and Glycine were tested as catalyst for the enolisation process. The rate of enolisation was found to increase with the increase in then ketone concentration , percentage composition of the solvent mixture and also with the increase in the dipole moments of the amino acids. Pseudofirst order rate kinetics was operational and the rate constants were found to increase with the increase in the amino acid molarity. Linear plots obtained for log of rate constants versus reciprocal of temperature which were in good agreement with Arrhenius equation. The values of thermodynamic parameters like Entropy (∆S≠ , Enthalpy (∆H≠, energy of activation (∆Ea and Free energy(∆F≠ were calculated and were found to be 2.6186 e.u. , 20.85 e.u. ,23.46 k cal mol-1 and 20.0 k cal mol-1 respectively.  © 2014 BCREC UNDIP. All rights reservedReceived: 31st July 2013; Revised: 8th November 2013; Accepted: 21st November 2013[How to Cite: Malhotra, S., Jaspal, D. (2014. Kinetics of the Enolisation Reaction of m-Nitro Acetophe-none Catalyzed by Amino Acids. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 16-22. (doi:10.9767/bcrec.9.1.5258.16-22][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5258.16-22

  19. β-N-methylamino-l-alanine causes neurological and pathological phenotypes mimicking Amyotrophic Lateral Sclerosis (ALS): the first step towards an experimental model for sporadic ALS.

    Science.gov (United States)

    de Munck, Estefanía; Muñoz-Sáez, Emma; Miguel, Begoña G; Solas, M Teresa; Ojeda, Irene; Martínez, Ana; Gil, Carmen; Arahuetes, Rosa Ma

    2013-09-01

    β-N-methylamino-l-alanine (L-BMAA) is a neurotoxic amino acid that has been related to various neurodegenerative diseases. The aim of this work was to analyze the biotoxicity produced by L-BMAA in vivo in rats, trying to elucidate its physiopathological mechanisms and to search for analogies between the found effects and pathologies like Amyotrophic Lateral Sclerosis (ALS). Our data demonstrated that the neurotoxic effects in vivo were dosage-dependent. For evaluating the state of the animals, a neurological evaluation scale was developed as well as a set of functional tests. Ultrastructural cell analysis of spinal motoneurons has revealed alterations both in endoplasmic reticulum and mitochondria. Since GSK3β could play a role in some neuropathological processes, we analyzed the alterations occurring in GSK3β levels in L-BMAA treated rats, we have observed an increase in the active form of GSK3β levels in lumbar spinal cord and motor cerebral cortex. On the other hand, (TAR)-DNA-binding protein 43 (TDP-43) increased in L-BMAA treated animals. Our results indicated that N-acetylaspartate (NAA) declined in animals treated with L-BMAA, and the ratio of N-acetylaspartate/choline (NAA/Cho), N-acetylaspartate/creatine (NAA/Cr) and N-acetylaspartate/choline+creatine (NAA/Cho+Cr) tended to decrease in lumbar spinal cord and motor cortex. This project offers some encouraging results that could help establishing the progress in the development of an animal model of sporadic ALS and L-BMAA could be a useful tool for this purpose. PMID:23688553

  20. L-BMAA induced ER stress and enhanced caspase 12 cleavage in human neuroblastoma SH-SY5Y cells at low nonexcitotoxic concentrations.

    Science.gov (United States)

    Okle, Oliver; Stemmer, Kerstin; Deschl, Ulrich; Dietrich, Daniel R

    2013-01-01

    The cyanobacterial β-N-methylamino-L-alanine (L-BMAA) is described as a low-potency excitotoxin, possibly a factor in the increased incidence of amyotrophic lateral sclerosis (ALS) and Parkinsonism-dementia complex (PDC) in Guam. The latter association is intensively disputed, as L-BMAA concentrations required for toxic effects exceed those assumed to occur via food. The question thus was raised whether L-BMAA leads to neurodegeneration at nonexcitotoxic conditions. Using human SH-SY5Y neuroblastoma cells, L-BMAA-transport, incorporation into proteins, and subsequent impairment of cellular protein homeostasis were investigated. Binding of L-BMAA to intracellular proteins, but no clear protein incorporation was detected in response to (14)C-L-BMAA exposures. Nevertheless, low L-BMAA concentrations (≥ 0.1mM, 48 h) increased protein ubiquitination, 20S proteasomal and caspase 12 activity, expression of the endoplasmic reticulum (ER) stress marker CHOP, and enhanced phosphorylation of elf2α in SH-SY5Y cells. In contrast, high L-BMAA concentrations (≥ 1mM, 48 h) increased reactive oxygen species and protein oxidization, which were partially ameliorated by coincubation with vitamin E. L-BMAA-mediated cytotoxicity was observable 48 h following ≥ 2mM L-BMAA treatment. Consequently, the data presented here suggest that low L-BMAA concentrations result in a dysregulation of the cellular protein homeostasis with ensuing ER stress that is independent from high-concentration effects such as excitotoxicity and oxidative stress. Thus, the latter could be a contributing factor in the onset and slow progression of ALS/PDC in Guam. PMID:23047912

  1. Synthesis of a molecularly imprinted sorbent for selective solid-phase extraction of β-N-methylamino-L-alanine.

    Science.gov (United States)

    Svoboda, Pavel; Combes, Audrey; Petit, Julia; Nováková, Lucie; Pichon, Valérie

    2015-11-01

    The aim of the work was to synthesize a molecularly imprinted material for the selective solid-phase extraction (SPE) of β-N-methylamino-L-alanine (L-2-amino-3-methylpropionic acid; BMAA) from cyanobacterial extracts. BMAA and its structural analogs that can be used as template are small, polar and hydrophilic molecules. These molecules are poorly soluble in organic solvents that are commonly used for the synthesis of acrylic-based polymers. Therefore, a sol gel approach was chosen to carry out the synthesis and the resulting sorbents were evaluated with different extraction procedures in order to determine their ability to selectively retain BMAA. The presence of imprinted cavities in the sorbent was demonstrated by comparing elution profiles obtained by using molecularly imprinted silica (MIS) and non-imprinted silica (NIS) as a control. The molecularly imprinted solid-phase extraction (MISPE) procedure was first developed in a pure medium (acetonitrile) and further optimized for the treatment of cyanobacterial samples. It was characterized by high elution recoveries (89% and 77% respectively in pure and in real media).The repeatability of the extraction procedure in pure medium, in real medium and the reproducibility of MIS synthesis all expressed as RSD values of extraction recovery of BMAA were equal to 3%, 12% and 5%, respectively. A MIS capacity of 0.34 µmol/g was measured. The matrix effects, which affected the quantification of BMAA when employing a mixed mode sorbent, were completely removed by adding a clean-up step of the mixed-mode sorbent extract on the MIS. PMID:26452922

  2. Measuring and modeling aqueous electrolyte/amino-acid solutions with ePC-SAFT

    International Nuclear Information System (INIS)

    Highlights: • Amino-acid solubilities and osmotic coefficients in ternary solutions containing one amino acids and one salt measured. • Weak salt influence on amino-acid solubilities except for salts containing Mg[2+] or NO3[−] (salting-in behavior). • Osmotic coefficients dominated by the solute with the highest molality. • Amino-acid solubilities and osmotic coefficients predicted reasonably with ePC-SAFT with deviations of 3.7% and 9.3%. • Predictions based on pure-component parameters for ions and amino acids using no ion/amino-acid fitting parameters. -- Abstract: In this work thermodynamic properties of electrolyte/amino acid/water solutions were measured and modeled. Osmotic coefficients at 298.15 K were measured by means of vapor-pressure osmometry. Amino-acid solubility at 298.15 K was determined gravimetrically. Considered aqueous systems contained one of the four amino acids: glycine, L-/DL-alanine, L-/DL-valine, and L-proline up to the respective amino-acid solubility limit and one of 13 salts composed of the ions Li+, Na+, K+, NH4+, Cl−, Br−, I−, NO3−, and SO42− at salt molalities of 0.5, 1.0, and 3.0 mol · kg−1, respectively. The data show that the salt influence is more pronounced on osmotic coefficients than on amino-acid solubility. The electrolyte Perturbed-Chain Statistical Association Theory (ePC-SAFT) was applied to model thermodynamic properties in aqueous electrolyte/amino-acid solutions. In previous works, this model had been applied to binary salt/water and binary amino acid/water systems. Without fitting any additional parameters, osmotic coefficients and amino-acid solubility in the ternary electrolyte/amino acid/water systems could be predicted with overall deviations of 3.7% and 9.3%, respectively, compared to the experimental data

  3. Preferential Treatment: Interaction Between Amino Acids and Minerals

    Science.gov (United States)

    Crapster-Pregont, E. J.; Cleaves, H. J.; Hazen, R. M.

    2008-12-01

    Amino acids are the building blocks of proteins and are important for some models of the origin of life. Polymerization of amino acids from dilute solution is unlikely without a scaffold or catalyst. The surfaces of early Earth minerals are the most likely candidates for this role. The surface adsorption behavior of 12 amino acids (L-alanine, L-serine, L-aspartic acid, L-proline, L- phenylalanine, L-valine, L-arginine, d-amino valeric acid, glycine, L-lysine, L-isoleucine, and B-alanine) on 21 minerals (quartz, calcite, enstatite, illite, olivine, pyrrhotite, pyrite, alkali basalt, albite, analcime, chlorite, barite, hydroxyl apatite, hematite, magnetite, aluminum hydroxide, kaolin, silica gel, corundum, rutile, and montmorillonite) was determined via batch adsorption experiments. Absorption was determined for concentrations between 10-4M and 10-6M in the presence of 0.1M NaCl, and between pH values of 3 and 9 at 25 degrees C. The equilibrated solutions were centrifuged, filtered, derivatized using a fluorescent amino group tag (dansyl-chloride) and analyzed by HPLC. Adsorption was standardized using BET surface area measurements for each mineral to give the number of mols of each amino acid adsorbed per square meter for each mineral. The results indicate an enormous difference in the adsorption of amino acids between minerals, along with major differences in the adsorption of individual amino acids on the same mineral surface. There is also a change in the absorbance of amino acids as the pH changes. Many previous studies of amino acid concentration and catalysis by minerals have used clay minerals because of their high surface areas, however, this data suggests that the surfaces of minerals such as calcite, quartz and pyrite have even higher affinities for amino acids. The results suggest mineral surfaces that could be optimal locations for the polymerization of molecules linked to the origin of life.

  4. Preparation and properties of BSA-loaded microspheres based on multi-(amino acid copolymer for protein delivery

    Directory of Open Access Journals (Sweden)

    Chen X

    2014-05-01

    Full Text Available Xingtao Chen,1 Guoyue Lv,1 Jue Zhang,2 Songchao Tang,2 Yonggang Yan,1 Zhaoying Wu,2 Jiacan Su,2 Jie Wei2 1College of Physical Science and Technology, Sichuan University, Chengdu, 2Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China Abstract: A multi-(amino acid copolymer (MAC based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 µm to 79.7 µm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery. Keywords: poly (amino acid copolymer, release, degradation

  5. Deinococcus arenae sp. nov., a novel species isolated from sand in South Korea.

    Science.gov (United States)

    Lee, Dongwook; Cha, Seho; Jang, Jun Hyeong; Seo, Taegun

    2016-07-01

    A Gram-negative strain, designated SA1(T), was isolated from a sand specimen from Yangyang Beach, South Korea. The cells of SA1(T) were observed to be red pigmented, strictly aerobic, non-motile rods. Strain SA1(T) was found to grow optimally at 30 °C and pH 7 (pH growth range, pH 7-9). Phylogenetic analyses of the 16S rRNA gene sequence of SA1(T) showed that the organism belongs to the phylum Deinococcus-Thermus and forms a branch within the genus Deinococcus, with Deinococcus actinosclerus BM2(T) as a close relative (99.8   % sequence similarity). The strain was found to be catalase positive and oxidase negative and to metabolise 2-ketogluconate, acetate, D,L-3-hydroxybutyrate, D-glucose, D-maltose, D-mannitol, D-mannose, D-melibiose, D-sorbitol, D-sucrose, glycogen, L-alanine, L-histidine, L-malate, L-proline and n-valerate. The guanine plus cytosine (G + C) base composition of the DNA was 69.5 mol %, as determined by the thermal denaturation method. The predominant respiratory quinone was identified as menaquinone with eight isoprene units (MK-8). The polar lipid profile of strain SA1(T) showed the presence of several unidentified glycolipids, phosphoglycolipids, phospholipids, aminophospholipids and unidentified lipids. In addition, the most abundant fatty acids of strain SA1(T) were identified as C15:1 ω6c, C16:1 ω7c and C17:0. On the basis of phylogenetic analyses, DNA-DNA hybridisation and biochemical characteristics, strain SA1(T) (=KCTC 33741(T) = JCM 31047(T)) is concluded to represent a novel species of the genus Deinococcus, for which the name Deinococcus arenae sp. nov. is proposed. PMID:27147067

  6. Genetics of Amino Acid Taste and Appetite.

    Science.gov (United States)

    Bachmanov, Alexander A; Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Reed, Danielle R; Tordoff, Michael G; Beauchamp, Gary K

    2016-07-01

    The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the consumption of some sweet-tasting amino acids (d-phenylalanine, d-tryptophan, and l-proline) are associated with polymorphisms of a taste receptor, type 1, member 3 gene (Tas1r3), and involve differential peripheral taste responsiveness. Strain differences in the consumption of some other sweet-tasting amino acids (glycine, l-alanine, l-glutamine, and l-threonine) do not depend on Tas1r3 polymorphisms and so must be due to allelic variation in other, as yet unknown, genes involved in sweet taste. Strain differences in the consumption of l-glutamate may depend on postingestive rather than taste mechanisms. Thus, genes and physiologic mechanisms responsible for strain differences in the consumption of each amino acid depend on the nature of its taste and postingestive properties. Overall, mouse strain differences in amino acid taste and appetite have a complex genetic architecture. In addition to the Tas1r3 gene, these differences depend on other genes likely involved in determining the taste and postingestive effects of amino acids. The identification of these genes may lead to the discovery of novel mechanisms that regulate amino acid taste and appetite. PMID:27422518

  7. Knockdown of cytosolic glutaredoxin 1 leads to loss of mitochondrial membrane potential: implication in neurodegenerative diseases.

    Directory of Open Access Journals (Sweden)

    Uzma Saeed

    Full Text Available Mitochondrial dysfunction including that caused by oxidative stress has been implicated in the pathogenesis of neurodegenerative diseases. Glutaredoxin 1 (Grx1, a cytosolic thiol disulfide oxido-reductase, reduces glutathionylated proteins to protein thiols and helps maintain redox status of proteins during oxidative stress. Grx1 downregulation aggravates mitochondrial dysfunction in animal models of neurodegenerative diseases, such as Parkinson's and motor neuron disease. We examined the mechanism underlying the regulation of mitochondrial function by Grx1. Downregulation of Grx1 by shRNA results in loss of mitochondrial membrane potential (MMP, which is prevented by the thiol antioxidant, alpha-lipoic acid, or by cyclosporine A, an inhibitor of mitochondrial permeability transition. The thiol groups of voltage dependent anion channel (VDAC, an outer membrane protein in mitochondria but not adenosine nucleotide translocase (ANT, an inner membrane protein, are oxidized when Grx1 is downregulated. We then examined the effect of beta-N-oxalyl amino-L-alanine (L-BOAA, an excitatory amino acid implicated in neurolathyrism (a type of motor neuron disease, that causes mitochondrial dysfunction. Exposure of cells to L-BOAA resulted in loss of MMP, which was prevented by overexpression of Grx1. Grx1 expression is regulated by estrogen in the CNS and treatment of SH-SY5Y cells with estrogen upregulated Grx1 and protected from L-BOAA mediated MMP loss. Our studies demonstrate that Grx1, a cytosolic oxido-reductase, helps maintain mitochondrial integrity and prevents MMP loss caused by oxidative insult. Further, downregulation of Grx1 leads to mitochondrial dysfunction through oxidative modification of the outer membrane protein, VDAC, providing support for the critical role of Grx1 in maintenance of MMP.

  8. Partial molar volume and partial molar compressibility of four homologous {alpha}-amino acids in aqueous sodium fluoride solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, K., E-mail: krpal25@yahoo.co [Department of Physics, Government College of Engg., Tirunelveli 627 007, Tamilnadu (India); Edwin Gladson, S., E-mail: aseg_win@rediffmail.co [Department of Physics, St. Xavier' s Catholic College of Engg., Chunkankadai 629 003, Tamilnadu (India)

    2011-06-15

    Research highlights: Partial molar volume indicates strong solute-cosolute interaction in the NaF solution. Partial molar compressibility results compliment partial molar volume results. Hydration number proves that sodium fluoride has dehydration effect on amino acids. Interactions between sodium fluoride and (NH{sub 3}{sup +},COO{sup -}) group of amino acid are stronger. - Abstract: Density and ultrasonic speed of four amino acids (glycine, L-alanine, L-valine, and L-leucine) in aqueous sodium fluoride solutions {l_brace}(0.1 to 0.5) M{r_brace} have been measured at T = (308.15, 313.15, and 318.15) K. Apparent molar volumes (V{sub {phi}}), partial molar volumes (V{sub {phi}}{sup 0}), transfer volumes ({Delta}V{sub {phi}}{sup 0}) and hydration number (n{sub H}) are evaluated using density data. Adiabatic compressibility ({beta}{sub s}), change ({Delta}{beta}{sub s}), and relative change in compressibility ({Delta}{beta}{sub s}/{beta}{sub 0}), apparent molar compressibility (K{sub {phi}}), partial molar compressibility (K{sub {phi}}{sup 0}), transfer compressibility ({Delta}K{sub {phi}}{sup 0}), and hydration number (n{sub H}) have been calculated using ultrasonic speed data. The linear correlation of V{sub {phi}}{sup 0},{Delta}V{sub {phi}}{sup 0},K{sub {phi}}{sup 0} and {Delta}K{sub {phi}}{sup 0} for a homologous series of amino acids have been used utilised to calculate the contribution of charged end groups (NH{sub 3}{sup +}, COO{sup -}), CH{sub 2} group and other alkyl chain of the amino acids. The analysis shows that the ion-ion interactions are much stronger than ion-hydrophobic interactions over the entire concentration range of sodium fluoride. It is observed that sodium fluoride has a strong dehydration effect on amino acids.

  9. L-aspartic acid transport by cat erythrocytes

    International Nuclear Information System (INIS)

    Cat and dog red cells are unusual in that they have no Na/K ATPase and contain low K and high Na intracellularly. They also show significant Na dependent L-aspartate (L-asp) transport. The authors have characterized this system in cat RBCs. The influx of 3H-L-asp (typically 2μM) was measured in washed RBCs incubated for 60 s at 370C in medium containing 140 mM NaCl, 5 mM Kcl, 2 mM CaCl2, 15 mM MOPS pH 7.4, 5 mM glucose, and 14C-PEG as a space marker. The cells were washed 3 times in the medium immediately before incubation which was terminated by centrifuging the RBCs through a layer of dibutylphthalate. Over an L-asp concentration range of 0.5-1000μM, influx obeyed Michaelis-Menten kinetics with a small added linear diffusion component. The Kt and Jmax of the saturable component were 5.40 +/- 0.34 μM and 148.8 +/- 7.2 μmol 1. cell-1h-1 respectively. Replacement of Na with Li, K, Rb, Cs or choline reduce influx to diffusion. With the addition of asp analogues (4+M L-asp, 40+M inhibitor), the following sequence of inhibition was observed (range 80% to 40% inhib.): L-glutamate > L-cysteine sulfonate > D-asp > L-cysteic acid > D-glutamate. Other amino acids such as L-alanine, L-proline, L-lysine, L-cysteine, and taurine showed no inhibition (<5%). These data suggest that cat red cells contain a high-affinity Na dependent transport system for L-asp, glutamate, and closely related analogues which resembles that found in the RBCs of other carnivores and in neural tissues

  10. Density and sound speed study of hydration of 1-butyl-3-methylimidazolium based amino acid ionic liquids in aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • Apparent and partial molar volumes of aqueous AAILs at T = (293.15 to 313.15) K. • Isothermal and adiabatic compressibilities of AAILs in aqueous solution at T = 298.15 K. • Method for direct estimation of hydration numbers due to electrostriction is given. • Internal pressure and hydration numbers for AAILs at T = 298.15 K. • Results obtained demonstrate kosmotropic behavior of AAILs. - Abstract: Amino acid ionic liquids (AAILs) have huge potential in the field of protein chemistry, enzymatic reactions, templates for synthetic study etc. which is due to their distinctive properties like unique acid-base characteristics, tunable hydrophobicity, hydrogen bonding ability and strong hydration effects. To explore the field of bio-ionic liquids for its real life applications and sustainable technology development, it is essential to have better understanding of these newly researched liquid salts in life’s most chosen medium, i.e. in aqueous medium, through study of their physicochemical properties in aqueous solutions. In this context, we are reporting herewith measurements and analysis of volumetric properties in the temperature range of (293.15 to 313.25) K and acoustic properties at 298.15 K in the concentration range of (0.05 to 0.5) mol · kg−1 for aqueous solutions of 1-butyl-3-methylimidazolium [Bmim] based amino acid ionic liquids, prepared from glycine, L-alanine, L-valine, L-leucine and L-isoleucine. The experimental density and sound speed data were used to obtain apparent, partial and limiting molar volumes as well as isentropic and isothermal compressibility properties. These data have been further used to understand electrostriction as well as concentration dependence of internal pressure. The hydration numbers for AAILs in aqueous medium were estimated from compressibility data using Passynski method and the estimated ionic hydration numbers are compared with those obtained using activity data. The results are explained in

  11. Functional and molecular characteristics of system L in human breast cancer cells.

    Science.gov (United States)

    Shennan, D B; Thomson, J; Barber, M C; Travers, M T

    2003-04-01

    The functional and molecular properties of system L in human mammary cancer cells (MDA-MB-231 and MCF-7) have been examined. All transport experiments were conducted under Na(+)-free conditions. alpha-Aminoisobutyric acid (AIB) uptake by MDA-MB-231 and MCF-7 cells was almost abolished by BCH (2-amino-2-norbornane-carboxylic acid). AIB uptake by MDA-MB-231 cells was also inhibited by L-alanine (83.6%), L-lysine (75.6%) but not by L-proline. Similarly, L-lysine and L-alanine, respectively, reduced AIB influx into MCF-7 cells by 45.3% and 63.7%. The K(m) of AIB uptake into MDA-MB-231 and MCF-7 cells was, respectively, 1.6 and 8.8 mM, whereas the V(max) was, respectively, 9.7 and 110.0 nmol/mg protein/10 min. AIB efflux from MDA-MB-231 and MCF-7 cells was trans-stimulated by BCH, L-glutamine, L-alanine, L-leucine, L-lysine and AIB (all at 2 mM). In contrast, L-glutamate, L-proline, L-arginine and MeAIB had no effect. The interaction between L-lysine and AIB efflux was one of low affinity. The fractional release of AIB from MDA-MB-231 cells was trans-accelerated by D-leucine and D-tryptophan but not by D-alanine. MDA-MB-231 and MCF-7 cells expressed LAT1 and CD98 mRNA. MCF-7 cells also expressed LAT2 mRNA. The results suggest that AIB transport in mammary cancer cells under Na(+)-free conditions is predominantly via system L which acts as an exchange mechanism. The differences in the kinetics of AIB transport between MDA-MB-231 and MCF-7 cells may be due to the differential expression of LAT2. PMID:12659948

  12. Molecular aggregation in crystalline 1:1 complexes of hydrophobic D- and L-amino acids. I. The L-isoleucine series.

    Science.gov (United States)

    Dalhus; Görbitz

    1999-06-01

    The amino acid L-isoleucine has been cocrystallized with seven selected D-amino acids including D-methionine [L-isoleucine-D-methionine (1/1), C(6)H(13)NO(2).C(5)H(11)NO(2)S, amino-acid side chain R = -CH(2)-CH(2)-S-CH(3)] and a homologous series from D-alanine [L-isoleucine-D-alanine (1/1), C(6)H(13)NO(2).C(3)H(7)NO(2), R = -CH(3)] through D-alpha-aminobutyric acid [L-isoleucine-D-alpha-aminobutyric acid (1/1), C(6)H(13)NO(2).C(4)H(9)NO(2), R = -CH(2)-CH(3)] and D-norvaline [L-isoleucine-D-norvaline (1/1), C(6)H(13)NO(2).C(5)H(11)NO(2), R = -CH(2)-CH(2)-CH(3)] to D-norleucine [L-isoleucine-D-norleucine (1/1), C(6)H(13)NO(2).C(6)H(13)NO(2), R = -CH(2)-CH(2)-CH(2)-CH(3)] with linear side chains, and D-valine [L-isoleucine-D-valine (1/1), C(6)H(13)NO(2).C(5)H(11)NO(2), R = -CH-(CH(3))(2)] and D-leucine [L-isoleucine-D-leucine (1/1), C(6)H(13)NO(2).C(6)H(13)NO(2), R = -CH(2)-CH-(CH(3))(2)] with branched side chains. All the crystal structures are divided into distinct hydrophilic and hydrophobic layers. In the five complexes with amino acids with linear side chains the polar parts of the D- and L-amino acids are related by pseudo-glide-plane symmetry, and four of them have remarkably similar molecular arrangements. The D-valine and D-leucine complexes, on the other hand, are structurally quite different with the polar parts of the D- and L-amino acids related by pseudo-inversion. Differences in the hydrogen-bond pattern in the two molecular arrangements are discussed. PMID:10927385

  13. Marinobacterium coralli sp. nov., isolated from mucus of coral (Mussismilia hispida).

    Science.gov (United States)

    Chimetto, Luciane A; Cleenwerck, Ilse; Brocchi, Marcelo; Willems, Anne; De Vos, Paul; Thompson, Fabiano L

    2011-01-01

    A Gram-negative, aerobic bacterium, designated R-40509(T), was isolated from mucus of the reef builder coral (Mussismilia hispida) located in the São Sebastião Channel, São Paulo, Brazil. The strain was oxidase-positive and catalase-negative, and required Na(+) for growth. Its phylogenetic position was in the genus Marinobacterium and the closest related species were Marinobacterium sediminicola, Marinobacterium maritimum and Marinobacterium stanieri; the isolate exhibited 16S rRNA gene sequence similarities of 97.5-98.0 % with the type strains of these species. 16S rRNA gene sequence similarities with other type strains of the genus Marinobacterium were below 96 %. DNA-DNA hybridizations between strain R-40509(T) and the type strains of the phylogenetically closest species of the genus Marinobacterium revealed less than 70 % DNA-DNA relatedness, supporting the novel species status of the strain. Phenotypic characterization revealed that the strain was able to grow at 15-42 °C and in medium containing up to 9 % NaCl. The isolate could be differentiated from phenotypically related species by several features, including its ability to utilize d-alanine, l-alanine, bromosuccinic acid, β-hydroxybutyric acid and α-ketovaleric acid, but not acetate or l-arabinose. It produced acetoin (Voges-Proskauer), but did not have esterase lipase (C8) or catalase activities. It possessed C(18 : 1)ω7c (35 %), summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c; 25 %) and C(16 : 0) (22 %) as major cellular fatty acids. The DNA G+C content was 58.5 mol%. The name Marinobacterium coralli sp. nov. is proposed to accommodate this novel isolate; the type strain is R-40509(T) (=LMG 25435(T) =CAIM 1449(T)). PMID:20154332

  14. Influence of nitrogen sources on growth and mycotoxin production by isolates of Pyrenophora tritici-repentis from wheat

    Institute of Scientific and Technical Information of China (English)

    Noureddine Bouras; Michael D. Holtz; Reem Aboukhaddour; Stephen E. Strelkova

    2016-01-01

    The fungus Pyrenophora tritici-repentis (Died.) Drechs. infects the leaves and kernels of wheat, causing tan spot and red smudge, respectively. Isolates of P. tritici-repentis have been reported to be both phytopathogenic and mycotoxigenic. This research investigates the influence of nitrogen sources on growth and production of mycotoxins by eight different isolates of P. tritici-repentis. A synthetic agar medium (SAM) was used with different nitrogen sources, both inorganic [(NH4Cl, NH4NO3 and (NH4)2SO4)] and organic (L-alanine, L-histidine, and L-lysine), at a concentration of 37.5 mmol L−1. Individual isolates exhibited different growth rates that varied according to the nitrogen source added to the medium. The choice of nitrogen source also had a major effect on production of the mycotoxins emodin, catenarin and islandicin. The highest concentrations of emodin, 54.40 ± 4.46μg g−1, 43.07 ± 23.39μg g−1 and 28.91 ± 4.64μg g−1 of growth medium, were produced on the complex medium (V8-potato dextrose agar) by the isolates Alg-H2, 331-2 and TS93-71B, respectively. A relatively high concentration of emodin also was produced by isolates Az35-5 (28.29 ± 4.71μg g−1 of medium) and TS93-71B (27.03 ± 4.09μg g−1 of medium) on synthetic medium supplemented with L-alanine. The highest concentrations of catenarin (174.54 ± 14.46μg g−1 and 104.87 ± 6.13μg g−1 of medium) were recorded for isolates TS93-71B and Alg-H2 on synthetic medium supplemented with L-alanine and NH4Cl, respectively. The highest concentration of islandicin (4.64 ± 0.36μg g−1 medium) was observed for isolate 331-2 in the presence of L-lysine. There was not a close relationship between mycelial growth and mycotoxin production by the fungal isolates. This is the first report on the influence of nitrogen sources on the production of mycotoxins by P. tritici-repentis.

  15. Efectos de la glutamina parenteral en pacientes sometidos a trasplante de médula ósea Effects of parenteral glutamine in patients submitted to bone marrow transplantation

    Directory of Open Access Journals (Sweden)

    C. Gómez Candela

    2006-02-01

    which these patients are submitted induce secondary effects, with a high metabolic stress. Glutamine is considered a conditionally essential amino acid, and has been shown effective in severe catabolic states. The aim of the study was to assess the effect of parenteral nutrition (PN therapy supplemented with glutamine on duration of nutritional support in a group of patients with BMT. We have also analyzed associated complications, the nutritional status, the clinical course at 6 months, differences as to type of transplantation, and oral ingestion capability. This is a phase IV, randomized, double blind, and parallel clinical trial, done at a single center. The study was performed on 49 patients, 29% male and 71% female patients, with ages between 21-63 years, distributed in 3 diagnostic groups (leukemia, lymphoma, and solid tumors, and admitted to the Hematology Department of our Hospital. Fifty percent of the patients in each group have received PN supplemented with glutamine (0.4 g/kg/day of L-alanine- L-glutamine, and the other 50% have received standard PN. RESULTS: we have not found significant differences nor at the beginning nor at the end of the study between both groups with regards to studied variables. CONCLUSIONS: PN is and effective therapy for maintenance of the nutritional status in patients submitted to a therapy with a, highly catabolic effect such as BMT. Although we have not been able to show the ef ficacy of glutamine supplementation in this study with the used dose, it does have been effective in other reports.

  16. Utilization of carbon sources by the soil microbial communities of different forest types in subtropical Australia%澳大利亚亚热带不同森林土壤微生物群落对碳源的利用

    Institute of Scientific and Technical Information of China (English)

    鲁顺保; 郭晓敏; 芮亦超; 周小奇; 陈成榕; 徐志红; 牛德奎

    2012-01-01

    the contribution rate of forest types in different combinations of variables for the statistical characterization of a single variable, and the merits of the decision variables were revealed. On soil microbial metabolic characteristics and soil properties, RDA analysis showed that the utilization of L-Alanine, L-Arginine, D-(+)-Glucose and N-Acetyl-glucosamine was greatly influenced by pH in kauri pine. Utilization of Citric acid, L-Malic acid and 7-Amino butyric acid were influenced by total phosphorus in hoop pine, and D-( +)-Fructose, Citric acid and L-cysteine-HCl were influenced by water, total nitrogen and total carbon in slash pine.