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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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. 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.

  3. Solid-state conformation of copolymers of ß-benzyl-L-aspartate with L-alanine, L-leucine, L-valine, γ-benzyl-L-glutamate, or ε-carbobenzoxy-L-lysine

    NARCIS (Netherlands)

    Sederel, Willem L.; Bantjes, Adriaan; Feijen, Jan; Anderson, James M.

    1980-01-01

    The solid-state conformation of copolymers of ß-benzyl-L-aspartate [L-Asp(OBzl)] with L-leucine (L-Leu), L-alanine (L-Ala), L-valine (L-Val), γ-benzyl-L-glutamate [L-Glu(OBzl)], or ε-carbobenzoxy-L-lysine (Cbz-L-Lys) has been studied by ir spectroscopy and circular dichroism (CD). The ir spectra in

  4. Prolonged continuous intravenous infusion of the dipeptide L-alanine- L-glutamine significantly increases plasma glutamine and alanine without elevating brain glutamate in patients with severe traumatic brain injury.

    Science.gov (United States)

    Nägeli, Mirjam; Fasshauer, Mario; Sommerfeld, Jutta; Fendel, Angela; Brandi, Giovanna; Stover, John F

    2014-07-02

    Low plasma glutamine levels are associated with worse clinical outcome. Intravenous glutamine infusion dose- dependently increases plasma glutamine levels, thereby correcting hypoglutaminemia. Glutamine may be transformed to glutamate which might limit its application at a higher dose in patients with severe traumatic brain injury (TBI). To date, the optimal glutamine dose required to normalize plasma glutamine levels without increasing plasma and cerebral glutamate has not yet been defined. Changes in plasma and cerebral glutamine, alanine, and glutamate as well as indirect signs of metabolic impairment reflected by increased intracranial pressure (ICP), lactate, lactate-to-pyruvate ratio, electroencephalogram (EEG) activity were determined before, during, and after continuous intravenous infusion of 0.75 g L-alanine-L-glutamine which was given either for 24 hours (group 1, n = 6) or 5 days (group 2, n = 6) in addition to regular enteral nutrition. Lab values including nitrogen balance, urea and ammonia were determined daily. Continuous L-alanine-L-glutamine infusion significantly increased plasma and cerebral glutamine as well as alanine levels, being mostly sustained during the 5 day infusion phase (plasma glutamine: from 295 ± 62 to 500 ± 145 μmol/ l; brain glutamine: from 183 ± 188 to 549 ± 120 μmol/ l; plasma alanine: from 327 ± 91 to 622 ± 182 μmol/ l; brain alanine: from 48 ± 55 to 89 ± 129 μmol/ l; p alanine-L-glutamine infusion (0.75 g/ kg/ d up to 5 days) increased plasma and brain glutamine and alanine levels. This was not associated with elevated glutamate or signs of potential glutamate-mediated cerebral injury. The increased nitrogen load should be considered in patients with renal and hepatic dysfunction. Clinicaltrials.gov NCT02130674. Registered 5 April 2014.

  5. The environmental neurotoxin β-N-methylamino-l-alanine (l-BMAA) is deposited into birds' eggs.

    Science.gov (United States)

    Andersson, Marie; Karlsson, Oskar; Brandt, Ingvar

    2018-01-01

    The neurotoxic amino acid β-N-methylamino-L-alanine (BMAA) has been implicated in the etiology of neurodegenerative disorders. BMAA is also a known developmental neurotoxin and research indicates that the sources of human and wildlife exposure may be more diverse than previously anticipated. The aim of the present study was therefore to examine whether BMAA can be transferred into birds' eggs. Egg laying quail were dosed with 14 C-labeled BMAA. The distribution of radioactivity in the birds and their laid eggs was then examined at different time points by autoradiography and phosphoimaging analysis. To evaluate the metabolic stability of the BMAA molecule, the distribution of 14 C-methyl- and 14 C-carboxyl-labeled BMAA were compared. The results revealed a pronounced incorporation of radioactivity in the eggs, predominantly in the yolk but also in the albumen. Imaging analysis showed that the concentrations of radioactivity in the liver decreased about seven times between the 24h and the 72h time points, while the concentrations in egg yolk remained largely unchanged. At 72h the egg yolk contained about five times the concentration of radioactivity in the liver. Both BMAA preparations gave rise to similar distribution pattern in the bird tissues and in the eggs, indicating metabolic stability of the labeled groups. The demonstrated deposition into eggs warrants studies of BMAAs effects on bird development. Moreover, birds' eggs may be a source of human BMAA exposure, provided that the laying birds are exposed to BMAA via their diet. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. 21 CFR 172.320 - Amino acids.

    Science.gov (United States)

    2010-04-01

    ... as the hydrochloride, sodium or potassium salts: L-Alanine L-Arginine L-Asparagine L-Aspartic acid L...-Serine L-Threonine Glutamic Acid Hydrochloride L-Isoleucine L-Lysine Monohydrochloride Monopotassium L...

  7. A fast method for ionized food identification: EPR

    International Nuclear Information System (INIS)

    Raffi, J.; Rubel, G.

    1990-01-01

    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 [fr

  8. 21 CFR 582.5118 - Alanine.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... § 582.5118 Alanine. (a) Product. Alanine (L- and DL-forms). (b) Conditions of use. This substance is...

  9. Prebiotic Peptide (Amide) Bond Synthesis Accelerated by Glycerol and Bicarbonate Under Neutral to Alkaline Dry-Down Conditions

    Science.gov (United States)

    Forsythe, J. G.; Weber, A. L.

    2017-07-01

    We report a new process for robust peptide bond synthesis in the pH 6–10 range that involves dry-down heating of amino acids in the presence of glycerol and bicarbonate (substrates: L-alanine, L-2-aminobutyric acid, β-alanine, isoserine).

  10. Characterization of germination receptors of Bacillus cereus ATCC 14579

    NARCIS (Netherlands)

    Hornstra, L.M.; Vries, de Y.P.; Wells-Bennik, M.H.J.; Vos, de W.M.; Abee, T.

    2006-01-01

    Specific amino acids, purine ribonucleosides, or a combination of the two is required for efficient germination of endospores of Bacillus cereus ATCC 14579. A survey including 20 different amino acids showed that L-alanine, L-cysteine, L-threonine, and L-glutamine are capable of initiating the

  11. Endothelial Proliferation and Increased Blood - Brain Barrier Permeability in the Basal Ganglia in a Rat Model of 3,4-Dihydrozyphenyl-L-Alanine-Induced Dyskinesia

    DEFF Research Database (Denmark)

    Westin, Jenny E.; Lindgren, Hanna S.; Gardi, Jonathan Eyal

    2006-01-01

    3,4-Dihydroxyphenyl-L-alanine (L-DOPA)-induced dyskinesia is associated with molecular and synaptic plasticity in the basal ganglia, but the occurrence of structural remodeling through cell genesis has not been explored. In this study, rats with 6-hydroxydopamine lesions received injections...

  12. Study of the origin of life using synchrotron radiation

    International Nuclear Information System (INIS)

    Nakagawa, Kazumichi; Tanaka, Masahito; Koketsu, Toshiyuki; Yamada, Toru; Onuki, Hideo

    2000-01-01

    Optical absorption spectra and CD (circular dichroism) spectra of amino acids were measured in the VUV region. Using these basic data, we made irradiation experiments. The excitation of n→π* transition near 200 nm of the L-aspartic acid, produced L-alanine and β-alanine. We succeeded to find L-alanyl-L- alanine(L-alanine dimer) for the case of irradiation to solid phase of L-alanine. (author)

  13. 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)

    Brezina, B.; Havrankova, M.

    1985-01-01

    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)

  14. Density functional and neural network analysis

    DEFF Research Database (Denmark)

    Jalkanen, K. J.; Suhai, S.; Bohr, Henrik

    1997-01-01

    Density functional theory (DFT) calculations have been carried out for hydrated L-alanine, L-alanyl-L-alanine and N-acetyl L-alanine N'-methylamide and examined with respect to the effect of water on the structure, the vibrational frequencies, vibrational absorption (VA) and vibrational circular...... dichroism (VCD) intensities. The large changes due to hydration on the structures, relative stability of conformers, and in the VA and VCD spectra observed experimentally are reproduced by the DFT calculations. Furthermore a neural network was constructed for reproducing the inverse scattering data (infer...

  15. 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

    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-DFTB, SCCDFTB......+disp, RHF, MP2, and DFT methodologies for the modeling studies with the goal of interpreting the experimentally measured vibrational spectra for these molecules to the greatest extent possible and to use this combined approach to understand the structure, function, and electronic properties...

  16. Solubility of the Proteinogenic α-Amino Acids in Water, Ethanol, and Ethanol–Water Mixtures

    Science.gov (United States)

    2018-01-01

    The addition of organic solvents to α-amino acids in aqueous solution could be an effective method in crystallization. We reviewed the available data on the solubility of α-amino acids in water, water–ethanol mixtures, and ethanol at 298.15 K and 0.1 MPa. The solubility of l-alanine, l-proline, l-arginine, l-cysteine, and l-lysine in water and ethanol mixtures and the solubility of l-alanine, l-proline, l-arginine, l-cysteine, l-lysine, l-asparagine, l-glutamine, l-histidine, and l-leucine in pure ethanol systems were measured and are published here for the first time. The impact on the solubility of amino acids that can convert in solution, l-glutamic acid and l-cysteine, was studied. At lower concentrations, only the ninhydrin method and the ultraperfomance liquid chromatography (UPLC) method yield reliable results. In the case of α-amino acids that convert in solution, only the UPLC method was able to discern between the different α-amino acids and yields reliable results. Our results demonstrate that α-amino acids with similar physical structures have similar changes in solubility in mixed water/ethanol mixtures. The solubility of l-tryptophan increased at moderate ethanol concentrations. PMID:29545650

  17. 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.

  18. The effect of ammonium sulfate on the solubility of amino acids in water at (298.15 and 323.15) K

    International Nuclear Information System (INIS)

    Ferreira, Luisa A.; Macedo, Eugenia A.; Pinho, Simao P.

    2009-01-01

    Using the analytical gravimetric method the solubility of glycine, DL-alanine, L-isoleucine, L-threonine, and L-serine in aqueous systems of (NH 4 ) 2 SO 4 , at (298.15 and 323.15) K, were measured for salt concentrations ranging up to 2.0 molal. In the electrolyte molality range studied the experimental observations showed that ammonium sulfate is a salting-in agent for most of the amino acids studied. Furthermore, the change of the relative solubility with electrolyte concentration shows a maximum, which makes the representation of the data by a simple empirical correlation such as the Setschenow equation difficult. For the development and evaluation of a robust thermodynamic framework that makes it possible to more profoundly understand aqueous amino acid solutions with ammonium sulfate additional experimental information is needed

  19. Enzymatic preparation of α- and β-deuterated or tritiated amino acids with l-methionine γ-lyase

    International Nuclear Information System (INIS)

    Esaki, N.; Sawada, S.; Tanaka, H.; Soda, K.

    1982-01-01

    L-Methionine γ-lyase catalyzes the exchange of α- and β-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium or tritium of solvents. The rate of α-hydrogen exchange with deuterium was about 40 times faster than that of the elimination reactions. The deuterium and tritium were exchanged also with the α- and β-hydrogens of the straight-chain amino acids which do not undergo the elimination: L-alanine, L-α-aminobutyrate, L-norvaline, and L-norleucine. No exchange occurs for the D-isomers, acidic L-amino acids, basic L-amino acids, and branched-chain L-amino acids, although α-hydrogen of glycine, L-trypotophan, and L-phenylalanine is exchanged slowly. These enzymatic hydrogen-exchange reactions facilitate specific labeling of the L-amino acids with deuterium and tritium

  20. Studies on radiolysis of amino acids, 1

    International Nuclear Information System (INIS)

    Oku, Tadatake

    1977-01-01

    In order to elucidate the radiolysis of amino acid, peptide, protein and enzyme, the radiolytic mechanisms of neutral amino acids (glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-serine, and L-threonine) and acidic amino acids (L-aspartic acid, L-glutamic acid and DL-amino-n-adipic acid) were studied in the presence of air or in the atmosphere nitrogen. An aqueous solution of 1 mM. of each amino acid was sealed in a glass ampoule under air or nitrogen. Irradiation of amino acid solutions was carried out with γ-rays of 60 Co at doses of 4.4-2,640x10 3 rads. The amino acids and the radiolytic products formed were determined by ion-exchange chromatography. From the results of determining amino acids and the radiolytic products formed and their G-values, the radiolytic mechanisms of the amino acids were discussed. (auth.)

  1. Aromatic radiofluorination with [18F]fluorine gas: 6-[18F]fluoro-L-dopa.

    Science.gov (United States)

    Firnau, G; Chirakal, R; Garnett, E S

    1984-11-01

    A new synthesis is described for the routine production of 3,4-dihydroxy-6-[18F]fluoro-phenyl-L-alanine (6-[18F]fluoro-L-dopa). The reaction between [18F]fluorine gas and 3,4-dihydroxyphenyl-L-alanine (L-dopa) in liquid hydrogen fluoride gave 2-, 5-, and 6-[18F]fluoro-L-dopa. 6-[18F]Fluoro-L-dopa was isolated by reverse-phase high-pressure liquid chromatography. From 100 mCi [18F]F2, the method produces 3 mCi of 6-[18F]fluoro-L-dopa at the end of synthesis.

  2. Deuterium isotope effect on 13C chemical shifts of tetrabutylammonium salts of Schiff bases amino acids.

    Science.gov (United States)

    Rozwadowski, Z

    2006-09-01

    Deuterium isotope effects on 13C chemical shift of tetrabutylammonium salts of Schiff bases, derivatives of amino acids (glycine, L-alanine, L-phenylalanine, L-valine, L-leucine, L-isoleucine and L-methionine) and various ortho-hydroxyaldehydes in CDCl3 have been measured. The results have shown that the tetrabutylammonium salts of the Schiff bases amino acids, being derivatives of 2-hydroxynaphthaldehyde and 3,5-dibromosalicylaldehyde, exist in the NH-form, while in the derivatives of salicylaldehyde and 5-bromosalicylaldehyde a proton transfer takes place. The interactions between COO- and NH groups stabilize the proton-transferred form through a bifurcated intramolecular hydrogen bond. Copyright (c) 2006 John Wiley & Sons, Ltd.

  3. [Cardioprotective effects of glutamine in patients with ischemic heart disease operated under conditions of extracorporeal blood circulation].

    Science.gov (United States)

    Lomivorotov, V V; Efremov, S M; Shmyrev, V A; Ponomarev, D N; Sviatchenko, A V; Kniaz'kova, L G

    2012-01-01

    It was conducted a study of glutamine cardioptotective effects during perioperative use in patients with ischemic heart disease, operated under CB. Exclusion criteria were: left ventricular ejection fraction less than 50%, diabetes melitus, myocardial infarction less than 3 months ago, Patients of the study group (n=25) had glutamine (20% solution N(2)-L-alanine-L-glutamine ("Dipeptiven" Fresenius Kabi, Germany); 0.4 g/kg/day. Patients of control group (n=25) received placebo (0.9% NaCl solution). The main indicators were the dynamics of troponin I, as well as central hemodynamics parameters. On the 1-st day after operation the concentration of troponin I was significantly lower in the glutamine-group compared placebo-group (1.280 (0.840-2.230) 2.410 (1.060-6.600) ng/ml; p=0.035). 4 hours after CB in a glutamine-group also had significantly large indicators of cardiac index (2.58 (2.34-2.91) l/min/m2 vs 2.03 (1.76-2.32)) l/min/m2; p=0,002) and stroke index (32.8 (27.8-36.0.) ml/m2 vs 26.1 (22.6-31.8) ml/m2; p=0.023). Systemic vascular resistance index was significantly lower in glutamine-group (1942 (1828-2209) dyn x s/cm(-5)/m2 vs 2456 (2400-3265) dyn x s/cm(-5)/m2; p=0.001). Conclusion. Perioperative use of N(2)-L-alanine-L-glutamine during the first 24 hours ofperioperative period gives cardioprotective effect in patients with ischemic heart disease operated under CB.

  4. Stronger Dopamine D1 Receptor-Mediated Neurotransmission in Dyskinesia.

    Science.gov (United States)

    Farré, Daniel; Muñoz, Ana; Moreno, Estefanía; Reyes-Resina, Irene; Canet-Pons, Júlia; Dopeso-Reyes, Iria G; Rico, Alberto J; Lluís, Carme; Mallol, Josefa; Navarro, Gemma; Canela, Enric I; Cortés, Antonio; Labandeira-García, José L; Casadó, Vicent; Lanciego, José L; Franco, Rafael

    2015-12-01

    Radioligand binding assays to rat striatal dopamine D1 receptors showed that brain lateralization of the dopaminergic system were not due to changes in expression but in agonist affinity. D1 receptor-mediated striatal imbalance resulted from a significantly higher agonist affinity in the left striatum. D1 receptors heteromerize with dopamine D3 receptors, which are considered therapeutic targets for dyskinesia in parkinsonian patients. Expression of both D3 and D1-D3 receptor heteromers were increased in samples from 6-hydroxy-dopamine-hemilesioned rats rendered dyskinetic by treatment with 3, 4-dihydroxyphenyl-L-alanine (L-DOPA). Similar findings were obtained using striatal samples from primates. Radioligand binding studies in the presence of a D3 agonist led in dyskinetic, but not in lesioned or L-DOPA-treated rats, to a higher dopamine sensitivity. Upon D3-receptor activation, the affinity of agonists for binding to the right striatal D1 receptor increased. Excess dopamine coming from L-DOPA medication likely activates D3 receptors thus making right and left striatal D1 receptors equally responsive to dopamine. These results show that dyskinesia occurs concurrently with a right/left striatal balance in D1 receptor-mediated neurotransmission.

  5. Modified chemically defined medium for enhanced respiratory growth of Lactobacillus casei and Lactobacillus plantarum groups.

    Science.gov (United States)

    Ricciardi, A; Ianniello, R G; Parente, E; Zotta, T

    2015-09-01

    Members of the Lactobacillus casei and Lactobacillus plantarum groups are capable of aerobic and respiratory growth. However, they grow poorly in aerobiosis in the currently available chemically defined media, suggesting that aerobic and respiratory growth require further supplementation. The effect of Tween 80, L-alanine, L-asparagine, L-aspartate, L-proline and L-serine on anaerobic and respiratory growth of Lact. casei N87 was investigated using a 2(5) factorial design. The effectiveness of modified CDM (mCDM) was validated on 21 strains of Lact. casei and Lact. plantarum groups. Tween 80 supplementation did not affect anaerobic growth, but improved respiratory growth. L-asparagine, L-proline and L-serine were stimulatory for respiring cells, while the presence of L-aspartate, generally, impaired biomass production. mCDM promoted the growth of Lact. casei and Lact. plantarum, with best results for strains showing a respiratory phenotype. The nutritional requirements of anaerobic and respiratory cultures of members of the Lact. casei and Lact. plantarum groups differ. Tween 80 and selected amino acids derived from pathways related to TCA cycle, pyruvate conversion and NADH recycling are required for respiration. The availability of mCDM will facilitate the study of aerobic metabolism of lactobacilli under controlled conditions. © 2015 The Society for Applied Microbiology.

  6. Small GSK-3 Inhibitor Shows Efficacy in a Motor Neuron Disease Murine Model Modulating Autophagy.

    Directory of Open Access Journals (Sweden)

    Estefanía de Munck

    Full Text Available Amyotrophic lateral sclerosis (ALS is a progressive motor neuron degenerative disease that has no effective treatment up to date. Drug discovery tasks have been hampered due to the lack of knowledge in its molecular etiology together with the limited animal models for research. Recently, a motor neuron disease animal model has been developed using β-N-methylamino-L-alanine (L-BMAA, a neurotoxic amino acid related to the appearing of ALS. In the present work, the neuroprotective role of VP2.51, a small heterocyclic GSK-3 inhibitor, is analysed in this novel murine model together with the analysis of autophagy. VP2.51 daily administration for two weeks, starting the first day after L-BMAA treatment, leads to total recovery of neurological symptoms and prevents the activation of autophagic processes in rats. These results show that the L-BMAA murine model can be used to test the efficacy of new drugs. In addition, the results confirm the therapeutic potential of GSK-3 inhibitors, and specially VP2.51, for the disease-modifying future treatment of motor neuron disorders like ALS.

  7. Kinetic and Mechanistic Studies on the Interaction of Glycyl-L-alanine, Glycyl-L-asparagine, and Glycyl-L-tyrosine with Hydroxopentaaquarhodium(III Ion

    Directory of Open Access Journals (Sweden)

    Biplab K. Bera

    2013-01-01

    Full Text Available The kinetics of the interaction of three glycine-containing dipeptides, namely, glycyl-L-alanine (L1-L′H, glycyl-L-asparagine (L2-L′H, and glycyl-L-tyrosine (L3-L′H with has been studied spectrophotometrically in aqueous medium as a function of the molar concentration of , [dipeptide], pH, and temperature at constant ionic strength. Reactions were studied at pH 4.3, where the substrate complex exists predominantly as the hydroxopentaaqua species and dipeptides as the zwitterion. The reaction has been found to proceed via two parallel paths: both processes are ligand dependent. The rate constant for the processes are and . The activation parameters for both the steps were evaluated using Eyring’s equation. The low and large negative value of as well as and indicate an associative mode of activation for both the aqua ligand substitution processes for both the parallel paths. The product of the reaction has been characterized by IR and ESI-mass spectroscopic analyses.

  8. Ab initio study of the enantio-selective magnetic-field-induced second harmonic generation in chiral molecules.

    Science.gov (United States)

    Rizzo, Antonio; Rikken, G L J A; Mathevet, R

    2016-01-21

    We present a systematic ab initio study of enantio-selective magnetic-field-induced second harmonic generation (MFISHG) on a set of chiral systems ((l)-alanine, (l)-arginine and (l)-cysteine; 3,4-dehydro-(l)-proline; (S)-α-phellandrene; (R,S)- and (S,S)-cystine disulphide; N-(4-nitrophenyl)-(S)-prolinol, N-(4-(2-nitrovinyl)-phenyl)-(S)-prolinol, N-(4-tricyanovinyl-phenyl)-(S)-prolinol, (R)-BINOL, (S)-BINAM and 6-(M)-helicene). The needed electronic frequency dependent cubic response calculations are performed within a density functional theory (DFT) approach. A study of the dependence of the property on the choice of electron correlation, on one-electron basis set extension and on the choice of magnetic gauge origin is carried out on a prototype system (twisted oxygen peroxide). The magnetic gauge dependence analysis is extended also to the molecules of the set. An attempt to analyze the structure-property relationships is also made, based on the results obtained for biphenyl (in a frozen twisted conformation), for prolinol and for some of their derivatives. The strength of the effect is discussed, in order to establish its measurability with a proposed experimental setup.

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

    International Nuclear Information System (INIS)

    Pal, Amalendu; Chauhan, Nalin

    2011-01-01

    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, V φ , partial molar volume at infinite dilution, V φ o , and experimental slope, S V were obtained and interpreted in terms of solute-solvent and solute-solute interactions. These data were used to calculate the (∂V φ 0 /∂T) P values. The partial molar volume of transfer, ΔV φ 0 from water to aqueous lactose solutions at infinite dilution has also been calculated. In addition to this, the linear correlation of V φ 0 with number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of NH 3 + COO - , and CH 2 groups to V φ 0 .

  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. Conformational properties of oxazole-amino acids: effect of the intramolecular N-H···N hydrogen bond.

    Science.gov (United States)

    Siodłak, Dawid; Staś, Monika; Broda, Małgorzata A; Bujak, Maciej; Lis, Tadeusz

    2014-03-06

    Oxazole ring occurs in numerous natural peptides, but conformational properties of the amino acid residue containing the oxazole ring in place of the C-terminal amide bond are poorly recognized. A series of model compounds constituted by the oxazole-amino acids occurring in nature, that is, oxazole-alanine (L-Ala-Ozl), oxazole-dehydroalanine (ΔAla-Ozl), and oxazole-dehydrobutyrine ((Z)-ΔAbu-Ozl), was investigated using theoretical calculations supported by FTIR and NMR spectra and single-crystal X-ray diffraction. It was found that the main feature of the studied oxazole-amino acids is the stable conformation β2 with the torsion angles φ and ψ of -150°, -10° for L-Ala-Ozl, -180°, 0° for ΔAla-Ozl, and -120°, 0° for (Z)-ΔAbu-Ozl, respectively. The conformation β2 is stabilized by the intramolecular N-H···N hydrogen bond and predominates in the low polar environment. In the case of the oxazole-dehydroamino acids, the π-electron conjugation that is spread on the oxazole ring and C(α)═C(β) double bond is an additional stabilizing interaction. The tendency to adopt the conformation β2 clearly decreases with increasing the polarity of environment, but still the oxazole-dehydroamino acids are considered to be more rigid and resistant to conformational changes.

  12. A preliminary study on the taste preferences of marble goby (Oxyeleotris marmoratus for amino acids

    Directory of Open Access Journals (Sweden)

    Leong-Seng Lim

    2015-08-01

    Full Text Available Taste preferences of marble goby (Oxyeleotris marmoratus for a mixture and several single L-isomer amino acids were determined through behavioral tests. Agar gel pellet was used as the medium to deliver the amino acids, and the fish acceptance on these pellets was evaluated by calculating the acceptance index (total pellet ingested/total pellet given; maximum and minimum values are 1 and 0, respectively. O. marmoratus were found to moderately accept L-alanine, L-glycine, and L-glutamine (index values 0.38, 0.32, and 0.27, respectively but reject L-cysteine, L-glutamic acid, L-lysine, L-serine and taurine (index value 0. The amino acids mixture (AAM showed the highest acceptance (0.91 by the fish. Such results indicated that the fish preferred the amino acids mixture over any of the single amino acids tested. Therefore, the amino acids mixture is potent to function as the feeding stimulant for the O. marmoratus.

  13. Nitrogen-fixing and cellulose-producing Gluconacetobacter kombuchae sp. nov., isolated from Kombucha tea.

    Science.gov (United States)

    Dutta, Debasree; Gachhui, Ratan

    2007-02-01

    A few members of the family Acetobacteraceae are cellulose-producers, while only six members fix nitrogen. Bacterial strain RG3T, isolated from Kombucha tea, displays both of these characteristics. A high bootstrap value in the 16S rRNA gene sequence-based phylogenetic analysis supported the position of this strain within the genus Gluconacetobacter, with Gluconacetobacter hansenii LMG 1527T as its nearest neighbour (99.1 % sequence similarity). It could utilize ethanol, fructose, arabinose, glycerol, sorbitol and mannitol, but not galactose or xylose, as sole sources of carbon. Single amino acids such as L-alanine, L-cysteine and L-threonine served as carbon and nitrogen sources for growth of strain RG3T. Strain RG3T produced cellulose in both nitrogen-free broth and enriched medium. The ubiquinone present was Q-10 and the DNA base composition was 55.8 mol% G+C. It exhibited low values of 5.2-27.77 % DNA-DNA relatedness to the type strains of related gluconacetobacters, which placed it within a separate taxon, for which the name Gluconacetobacter kombuchae sp. nov. is proposed, with the type strain RG3T (=LMG 23726T=MTCC 6913T).

  14. Effects of Dietary Garlic Extracts on Whole Body Amino Acid and Fatty Acid Composition, Muscle Free Amino Acid Profiles and Blood Plasma Changes in Juvenile Sterlet Sturgeon,

    Directory of Open Access Journals (Sweden)

    Dong-Hoon Lee

    2012-10-01

    Full Text Available A series of studies were carried out to investigate the supplemental effects of dietary garlic extracts (GE on whole body amino acids, whole body and muscle free amino acids, fatty acid composition and blood plasma changes in 6 month old juvenile sterlet sturgeon (Acipenser ruthenus. In the first experiment, fish with an average body weight of 59.6 g were randomly allotted to each of 10 tanks (two groups of five replicates, 20 fish/tank and fed diets with (0.5% or without (control GE respectively, at the level of 2% of fish body weight per day for 5 wks. Whole body amino acid composition between the GE and control groups were not different (p>0.05. Among free amino acids in muscle, L-glutamic acid, L-alanine, L-valine, L-leucine and L-phenylalanine were significantly (p0.05 were noticed at 12 h (74.6 vs 73.0. Plasma insulin concentrations (μIU/ml between the two groups were significantly (p<0.05 different at 1 (10.56 vs 5.06 and 24 h (32.56 vs 2.96 after feeding. The present results suggested that dietary garlic extracts could increase dietary glucose utilization through the insulin secretion, which result in improved fish body quality and feed utilization by juvenile sterlet sturgeon.

  15. Fabrication and evaluation of evanescent wave absorption based polyaniline-cladding modified fiber optic urea biosensor

    Science.gov (United States)

    Botewad, S. N.; Pahurkar, V. G.; Muley, G. G.

    2018-01-01

    The fabrication and study of cladding modified intrinsic fiber optic urea biosensor has been reported in the present investigation. A simple cladding modification technique was used to construct the sensor by uncladding the small portion from optical fiber. Further bare core was decorated by supportive porous, chemically and optically sensitive matrix material polyaniline (PANI) as an active cladding for enzyme residency. Enzyme-urease (Urs) was cross-linked on the active cladding region via glutaraldehyde solution. Confirmation of the prepared PANI in proper form determined by ultraviolet-visible and Fourier transform infrared spectroscopic techniques. X-ray diffraction technique was employed for nature and compatibility examination of PANI. Sensor parameters such as sensitivity, selectivity, stability and lower detection limit have been analyzed by absorption variation study in evanescent wave field. The response of prepared sensor was studied towards urea in the wide concentration range 100 nM-100 mM and confirmed its lowest detection limit as 100 nM. The stability of sensor was found 28 days with little variation in response. The fabricated sensor has not shown any response towards interference species like glucose, ascorbic acid, L-alanine, L-arginine and their combination with urea solution and hence found selective for urea solution only.

  16. 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)

  17. GC-MS-Based Endometabolome Analysis Differentiates Prostate Cancer from Normal Prostate Cells

    Directory of Open Access Journals (Sweden)

    Ana Rita Lima

    2018-03-01

    Full Text Available Prostate cancer (PCa is an important health problem worldwide. Diagnosis and management of PCa is very complex because the detection of serum prostate specific antigen (PSA has several drawbacks. Metabolomics brings promise for cancer biomarker discovery and for better understanding PCa biochemistry. In this study, a gas chromatography–mass spectrometry (GC-MS based metabolomic profiling of PCa cell lines was performed. The cell lines include 22RV1 and LNCaP from PCa with androgen receptor (AR expression, DU145 and PC3 (which lack AR expression, and one normal prostate cell line (PNT2. Regarding the metastatic potential, PC3 is from an adenocarcinoma grade IV with high metastatic potential, DU145 has a moderate metastatic potential, and LNCaP has a low metastatic potential. Using multivariate analysis, alterations in levels of several intracellular metabolites were detected, disclosing the capability of the endometabolome to discriminate all PCa cell lines from the normal prostate cell line. Discriminant metabolites included amino acids, fatty acids, steroids, and sugars. Six stood out for the separation of all the studied PCa cell lines from the normal prostate cell line: ethanolamine, lactic acid, β-Alanine, L-valine, L-leucine, and L-tyrosine.

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

    International Nuclear Information System (INIS)

    Gancheva, Veselka; Sagstuen, Einar; Yordanov, Nicola D.

    2006-01-01

    Polycrystalline phenyl-alanine and perdeuterated l-α-alanine (l-α-alanine-d 4 ) 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 (CD 3 CD(NH 2 )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, R 1 =CH 3 C*(H)COOH and R 2 =H 3 N + -C*(CH 3 )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-d 4 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

  19. Serum metabolomics reveals the mechanistic role of functional foods and exercise for obesity management in rats.

    Science.gov (United States)

    Ammar, Naglaa M; Farag, Mohamed A; Kholeif, Tahani E; Metwally, Nadia S; El-Sheikh, Nora M; El Gendy, Abdel Nasser; Abdel-Hamid, Abdel-Hamid Z

    2017-08-05

    Obesity is one of the independent risk factors for several health problems, leading to metabolic perturbations and for which analytical approaches i.e., "metabolomics" is needed to monitor the underlying metabolic changes. In this study, obesity associated changes were assessed via serum metabolites analysis of obese rats fed on high fat diet. Obese rats were subsequently treated with different functional foods used for obesity management including pomegranate, grapefruit, and red cabbage in parallel to swimming exercise. Serum samples were analyzed using gas chromatography-mass spectrometry (GC-MS) followed by multivariate data analysis to classify samples and determine if such treatments can help revert obesity related metabolic changes back to normal status. Results led to the identification of several novel metabolites biomarkers for obesity related to lipids, amino acids and central tricarboxylic acid (TCA) pathways. Distinct variations in metabolite levels were recorded in obese rats compared to normal ones including l-aspartic, l-alanine, l-glutamine, l-glycine, phenylethanolamine, α-aminobutyric acid and β-hydroxybutyric acid. Metabolomics approach developed herein provides novel insight onto the metabolic disturbances associated with obesity, which will assist in future drug design that can help mitigate against such changes. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. 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)

    Buschmann, H.-J.; Schollmeyer, E.; Mutihac, L.

    2003-01-01

    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

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

    Science.gov (United States)

    Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

    2014-01-01

    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. PMID:24855351

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

    International Nuclear Information System (INIS)

    Walter, U.; Luthe, H.; Soeling, H.D.; Gerhart, F.

    1975-01-01

    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- 3 H] alanine + glutamic-pyruvic transaminase, L-[3- 3 H] alanine + α-oxoglutarate + glutamic-pyruvic transaminase, L-[3- 3 H] glutamate + glutamic-oxaloacetic transaminase, L-[3- 3 H] glutamate + oxalocetate + glutamic-oxaloacetic transaminase, and L-[3- 3 H] glutamate + pyruvate + glutamic-pyruvic transaminase as shown by the appearance of 3 H 2 O. No hydrogen exchange at the β-carbon of L-glutamate occurred during incubation of L-[3- 3 H] -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 2 H 2 O-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.) [de

  3. Resolution and isolation of enantiomers of (±)-isoxsuprine using thin silica gel layers impregnated with L-glutamic acid, comparison of separation of its diastereomers prepared with chiral derivatizing reagents having L-amino acids as chiral auxiliaries.

    Science.gov (United States)

    Bhushan, Ravi; Nagar, Hariom

    2015-03-01

    Thin silica gel layers impregnated with optically pure l-glutamic acid were used for direct resolution of enantiomers of (±)-isoxsuprine in their native form. Three chiral derivatizing reagents, based on DFDNB moiety, were synthesized having l-alanine, l-valine and S-benzyl-l-cysteine as chiral auxiliaries. These were used to prepare diastereomers under microwave irradiation and conventional heating. The diastereomers were separated by reversed-phase high-performance liquid chromatography on a C18 column with detection at 340 nm using gradient elution with mobile phase containing aqueous trifluoroacetic acid and acetonitrile in different compositions and by thin-layer chromatography (TLC) on reversed phase (RP) C18 plates. Diastereomers prepared with enantiomerically pure (+)-isoxsuprine were used as standards for the determination of the elution order of diastereomers of (±)-isoxsuprine. The elution order in the experimental study of RP-TLC and RP-HPLC supported the developed optimized structures of diastereomers based on density functional theory. The limit of detection was 0.1-0.09 µg/mL in TLC while it was in the range of 22-23 pg/mL in HPLC and 11-13 ng/mL in RP-TLC for each enantiomer. The conditions of derivatization and chromatographic separation were optimized. The method was validated for accuracy, precision, limit of detection and limit of quantification. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Interaction of bovine serum albumin with N-acyl amino acid based anionic surfactants: Effect of head-group hydrophobicity.

    Science.gov (United States)

    Ghosh, Subhajit; Dey, Joykrishna

    2015-11-15

    The function of a protein depends upon its structure and surfactant molecules are known to alter protein structure. For this reason protein-surfactant interaction is important in biological, pharmaceutical, and cosmetic industries. In the present work, interactions of a series of anionic surfactants having the same hydrocarbon chain length, but different amino acid head group, such as l-alanine, l-valine, l-leucine, and l-phenylalanine with the transport protein, bovine serum albumin (BSA), were studied at low surfactant concentrations using fluorescence and circular dichroism (CD) spectroscopy, and isothermal titration calorimetry (ITC). The results of fluorescence measurements suggest that the surfactant molecules bind simultaneously to the drug binding site I and II of the protein subdomain IIA and IIIA, respectively. The fluorescence as well as CD spectra suggest that the conformation of BSA goes to a more structured state upon surfactant binding at low concentrations. The binding constants of the surfactants were determined by the use of fluorescence as well as ITC measurements and were compared with that of the corresponding glycine-derived surfactant. The binding constant values clearly indicate a significant head-group effect on the BSA-surfactant interaction and the interaction is mainly hydrophobic in nature. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Raman spectra of amino acids and their aqueous solutions.

    Science.gov (United States)

    Zhu, Guangyong; Zhu, Xian; Fan, Qi; Wan, Xueliang

    2011-03-01

    Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids (L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials. Copyright © 2010 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Badelin, Valentin G.; Smirnov, Valeriy I.

    2011-01-01

    Highlights: ► Enthalpies of L-phenylalanine dissolution have been measured in aqueous methanol, ethanol, 1-propanol and 2-propanol. ► The measured data were reported as functions of composition of water + alcohol mixtures. ► Enthalpy coefficients of pair-wise interactions have been analyzed in terms of McMillan-Mayer theory. ► 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 2 ∼0.4. The standard enthalpies of solution Δ sol H° and transfer Δ tr H° 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.

  7. 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.

  8. The Uses of 2-Ethoxy-(4H)-3,1-benzoxazin-4-one in the Synthesis of Some Quinazolinone Derivatives of Antimicrobial Activity

    Science.gov (United States)

    El-Hashash, Maher A.; Darwish, Khalid M.; Rizk, Sameh A.; El-Bassiouny, Fakhry A.

    2011-01-01

    The behavior of 2-ethoxy-(4H)-3,1-benzoxazin-4-one (1) towards nitrogen nucleophiles, e.g. ethanolamine, aromatic amines (namely: p-toluidine, p-anisidine, p-hydroxyaniline, o-hydroxyaniline, o-bromoaniline, o-phenylenediamine, p-phenylenediamine, o-tolidinediamine) p-aminobenzoic acid, glucosamine hydrochloride, 2-aminonicotinic acid, 1-naphthalenesulfonic acid hydrazide, n-decanoic acid hydrazide, benzoic acid hydrazide, semicarbazide, aminoacids (e.g. D,L-alanine, L-asparagine, L-arginine) and derivatives of 2-aminothiodiazole has been investigated. The behavior of the benzoxazinone towards a selected sulfur nucleophile, L-cysteine, has also been discussed. Formation of an amidine salt as a reaction intermediate has been assumed. The effect of solvent in some reactions has been elucidated. The structures of all the novel quinazoline and quinazolinone derivatives, obtained by heterocyclic ring opening and ring closure were inferred by the IR, MS as well as 1H-NMR spectral analysis. Moreover, the antimicrobial potential of some of the new synthesized derivatives has been evaluated.

  9. The Uses of 2-Ethoxy-(4H-3,1-benzoxazin-4-one in the Synthesis of Some Quinazolinone Derivatives of Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Fakhry A. El-Bassiouny

    2011-07-01

    Full Text Available The behavior of 2-ethoxy-(4H-3,1-benzoxazin-4-one (1 towards nitrogen nucleo-philes, e.g. ethanolamine, aromatic amines (namely: p-toluidine, p-anisidine, p-hydroxyaniline, o-hydroxyaniline, o-bromoaniline, o-phenylenediamine, p-phenylene- diamine, o-tolidinediamine p-aminobenzoic acid, glucosamine hydrochloride,  2-amino- nicotinic acid, 1-naphthalenesulfonic acid hydrazide, n-decanoic acid hydrazide, benzoic acid hydrazide, semicarbazide, aminoacids (e.g. D,L-alanine, L-asparagine, L-arginine and derivatives of 2-aminothiodiazole has been investigated. The behavior of the benzoxazinone towards a selected sulfur nucleophile, L-cysteine, has also been discussed. Formation of an amidine salt as a reaction intermediate has been assumed. The effect of solvent in some reactions has been elucidated. The structures of all the novel quinazoline and quinazolinone derivatives, obtained by heterocyclic ring opening and ring closure were inferred by the IR, MS as well as 1H-NMR spectral analysis. Moreover, the antimicrobial potential of some of the new synthesized derivatives has been evaluated.

  10. Spider dragline silk composite films doped with linear and telechelic polyalanine: Effect of polyalanine on the structure and mechanical properties.

    Science.gov (United States)

    Tsuchiya, Kousuke; Ishii, Takaoki; Masunaga, Hiroyasu; Numata, Keiji

    2018-02-26

    Spider dragline silks have attracted intensive attention as eco-friendly tough materials because of their excellent mechanical property and biomass-based origin. Composite films based on a recombinant spider dragline silk protein (ADF3) from Araneus diadematus were prepared by doping with linear or telechelic poly(L-alanine) (L- or T-polyA, respectively) as a reinforcing agent. Higher tensile strength and toughness of the composite films were achieved with the addition of polyA compared with the tensile strength and toughness of the silk-only film. The difference in the reinforcing behavior between L- and T-polyA was associated with their primary structures, which were revealed by wide angle X-ray diffraction analysis. L-polyA showed a tendency to aggregate in the composite films and induce crystallization of the inherent silk β-sheet to afford rigid but brittle films. By contrast, T-polyA dispersion in the composite films led to the formation of β-sheet crystal of both T-polyA and the inherent silk, which imparted high strength and toughness to the silk films.

  11. 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(1)H, 3-methyl-4-fluoro-acetophenone alanine L(2)H, 3-methyl-4-fluoro acetophenone tryptophan L(3)H, 3-methyl-4-fluoro-acetophenone valine L(4)H, 3-methyl-4-fluoro-acetophenone isoleucine L(5)H and 3-methyl-4-fluoro-acetophenone glycine L(6)H) 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 ((1)H, (13)C, (19)F and (119)Sn 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. Copyright 2010 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Kuenig, G.; Niedermeyer, B.; Krause, F.; Hartmann, J.; Deckert, J.; Heinsen, H.; Beckmann, H.; Riederer, P.; Ransmayr, G.

    1994-01-01

    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)

  13. The effect of immunonutrition (glutamine, alanine on fracture healing

    Directory of Open Access Journals (Sweden)

    Abdullah Küçükalp

    2014-11-01

    Full Text Available Background: There have been various studies related to fracture healing. Glutamine is an amino acid with an important role in many cell and organ functions. This study aimed to make a clinical, radiological, and histopathological evaluation of the effects of glutamine on fracture healing. Methods: Twenty rabbits were randomly allocated into two groups of control and immunonutrition. A fracture of the fibula was made to the right hind leg. All rabbits received standard food and water. From post-operative first day for 30 days, the study group received an additional 2 ml/kg/day 20% L-alanine L-glutamine solution via a gastric catheter, and the control group received 2 ml/kg/day isotonic via gastric catheter. At the end of 30 days, the rabbits were sacrificed and the fractures were examined clinically, radiologically, and histopathologically in respect to the degree of union. Results: Radiological evaluation of the control group determined a mean score of 2.5 according to the orthopaedists and 2.65 according to the radiologists. In the clinical evaluation, the mean score was 1.875 for the control group and 2.0 for the study group. Histopathological evaluation determined a mean score of 8.5 for the control group and 9.0 for the study group. Conclusion: One month after orally administered glutamine–alanine, positive effects were observed on fracture healing radiologically, clinically, and histopathologically, although no statistically significant difference was determined.

  14. Tin(IV Complexes of Schiff Base Derived from Amino Acid: Synthesis and Characteristic Spectral Studies

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    Robina Aman

    2013-01-01

    Full Text Available A new series of tin(IV complexes of general formula [Sn(L-1(Opri2] (1, [Sn(HL-12(Opri2] (2, [Sn(L-2(Opri2] (3, [Sn(HL-22(Opri2] (4, (L is dianion of Schiff bases derived from the condensation of 2-hydroxy-1-naphthaldehyde with glycine (L-1 and Lβ-alanine (L-2 was synthesized by reaction of tin(IV tetraisopropoxide with the ligands, in appropriate stoichiometric ratios (1 : 1 and 1 : 2. This would result in the replacement of the isopropoxide group from the tin(IV tetraisopropoxide and hydrogen(s from ligand with the azeotropical removal of isopropanol. An attempt has been made to prove the structure of the resulting complexes on the basis of elemental analysis, IR, 1H nuclear magnetic resonance. The binding site of the ligand was identified by IR spectroscopic measurement. In these complexes, the tin(IV centre is bonded to oxygen atom of the hydroxyl or carboxylate group. The spectra data suggest that the carboxylate group is coordinated to tin(IV centre in monodentate manner.

  15. The effects of additives on the crystal habit of monosodium L-glutamate monohydrate

    Science.gov (United States)

    Sano, Chiaki; Nagashima, Nobuya; Kawakita, Tetsuya; Iitaka, Yoichi

    1990-01-01

    The effects of various amino acids and organic acids on the habit of MSG crystals have been investigated. The addition of L-alanine (L-Ala) and L-lysine (L-Lys) made the MSG crystals short and thick, but D-glutamic acid (D-Glu), γ-amino butylic acid (γ-ABA) and L-pyrrolidone carboxylic acid (L-PCA) made the crystals long and thin. HPLC analysis of the end and the side faces of the MSG crystals grown with the additives revealed that the concentrations of L-Lys and L-Ala were higher at the end faces than at the side faces; but those of D-Glu, γ-ABA and L-PCA were higher at the side faces than at the end faces. The facts indicate that habit modifications of the MSG crystals, brought about in the presence of these additives, are due to stereo-selective adsorption of the additives on the crystal faces. Finally, the cause leading to the differences in adsorption of the additives on the crystal faces of MSG is discussed in relation to the stacking density of L-Glu molecules and Na ions on each face using the results of the X-ray structure analysis.

  16. Rhizobium hidalgonense sp. nov., a nodule endophytic bacterium of Phaseolus vulgaris in acid soil.

    Science.gov (United States)

    Yan, Jun; Yan, Hui; Liu, Li Xue; Chen, Wen Feng; Zhang, Xiao Xia; Verástegui-Valdés, Myrthala M; Wang, En Tao; Han, Xiao Zeng

    2017-01-01

    One Gram-negative, aerobic, motile, rod-shaped bacterium, designated as FH14 T , was isolated from nodules of Phaseolus vulgaris grown in Hidalgo State of Mexico. Results based upon 16S rRNA gene (≥99.8 % similarities to known species), concatenated sequence (recA, atpD and glnII) analysis of three housekeeping genes (≤93.4 % similarities to known species) and average nucleotide identity (ANI) values of genome sequence (ranged from 87.6 to 90.0 % to related species) indicated the distinct position of strain FH14 T within the genus Rhizobium. In analyses of symbiotic genes, only nitrogen fixation gene nifH was amplified that had nucleotide sequence identical to those of the bean-nodulating strains in R. phaseoli and R. vallis, while nodulation gene nodC gene was not amplified. The failure of nodulation to its original host P. vulgaris and other legumes evidenced the loss of its nodulation capability. Strain FH14 T contained summed feature 8 (C 18:1 ω6c/C 18:1 ω7c, 59.96 %), C 16:0 (10.6 %) and summed feature 2 (C 12:0 aldehyde/unknown 10.928, 10.24 %) as the major components of cellular fatty acids. Failure to utilize alaninamide, and utilizing L-alanine, L-asparagine and γ-amino butyric acid as carbon source, distinguished the strain FH14 T from the type strains for the related species. The genome size and DNA G+C content of FH14 T were 6.94 Mbp and 60.8 mol %, respectively. Based on those results, a novel specie in Rhizobium, named Rhizobium hidalgonense sp. nov., was proposed, with FH14 T (=HAMBI 3636 T  = LMG 29288 T ) as the type strain.

  17. Effect of media, additives, and incubation conditions on the recovery of high pressure and heat-injured Clostridium botulinum spores.

    Science.gov (United States)

    Reddy, N R; Tetzloff, R C; Skinner, G E

    2010-08-01

    The effect of additives and post-treatment incubation conditions on the recovery of high pressure and heat-injured (i.e., processed at 620 MPa and 95 and 100 degrees C for 5 min) spores of Clostridium botulinum strains, 62-A (proteolytic type A) and 17-B (nonproteolytic type B) was studied. High pressure and heat-injured spores were inoculated into TPGY (Trypticase-Peptone-Glucose-Yeast extract) anaerobic broth media containing additives (lysozyme, L-alanine, L-aspartic acid, dipicolonic acid, sodium bicarbonate, and sodium lactate) at various concentrations (0-10 microg/ml) individually or in combination. The spore counts of high pressure and heat-injured 62-A and 17-B recovered from TPGY broth containing lysozyme (10 microg/ml) incubated for 4 months versus that recovered from peptone-yeast extract-glucose-starch (PYGS) plating agar containing lysozyme (10 microg/ml) incubated under anaerobic conditions for 5 days were also compared. None of the additives either individually or in combination in TPGY broth improved recovery of injured spore enumeration compared to processed controls without additives. Addition of lysozyme at concentrations of 5 and 10 microg/ml in TPGY broth improved initial recovery of injured spores of 17-B during the first 4 days of incubation but did not result in additional recovery at the end of the 4 month incubation compared to the processed control without lysozyme. Adding lysozyme at a concentration of 10 microg/ml to PYGS plating agar resulted in no effect on the recovery of high pressure and heat-injured 62-A and 17-B spores. The recovery counts of high pressure and heat-injured spores of 62-A and 17-B were lower (i.e., <1.0 log units) with PYGS plating agar compared to the MPN method using TPGY broth as the growth medium. Published by Elsevier Ltd.

  18. Development and validation of a rapid, selective, and sensitive LC-MS/MS method for simultaneous determination of D- and L-amino acids in human serum: application to the study of hepatocellular carcinoma.

    Science.gov (United States)

    Han, Minlu; Xie, Mengyu; Han, Jun; Yuan, Daoyi; Yang, Tian; Xie, Ying

    2018-04-01

    A validated liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of D- and L-amino acids in human serum. Under the optimum conditions, except for DL-proline, L-glutamine, and D-lysine, the enantioseparation of the other 19 enantiomeric pairs of proteinogenic amino acids and nonchiral glycine was achieved with a CROWNPAK CR-I(+) chiral column within 13 min. The lower limits of quantitation for L-amino acids (including glycine) and D-amino acids were 5-56.25 μM and 0.625-500 nM, respectively, in human serum. The intraday precision and interday precision for all the analytes were less than 15%, and the accuracy ranged from -12.84% to 12.37% at three quality control levels. The proposed method, exhibiting high rapidity, enantioresolution, and sensitivity, was successfully applied to the quantification of D- and L-amino acid levels in serum from hepatocellular carcinoma patients and healthy individuals. The serum concentrations of L-arginine, L-isoleucine, L-aspartate, L-tryptophan, L-alanine, L-methionine, L-serine, glycine, L-valine, L-leucine, L-phenylalanine, L-threonine, D-isoleucine, D-alanine, D-glutamate, D-glutamine, D-methionine, and D-threonine were significantly reduced in the hepatocellular carcinoma patients compared with the healthy individuals (P < 0.01). D-Glutamate and D-glutamine were identified as the most downregulated serum markers (fold change greater than 1.5), which deserves further attention in hepatocellular carcinoma research. Graphical abstract Simultaneous determination of D- and L-amino acids in human serum from hepatocellular carcinoma patients and healthy individuals. AA amino acid, HCC hepatocellular carcinoma, LC liquid chromatography, MS/MS tandem mass spectrometry, NC normal control, TIC total ion chromatogram.

  19. Compatibility of Amino Acids in Ice Ih: Implications for the Origin of Life.

    Science.gov (United States)

    Hao, Jihua; Giovenco, Elena; Pedreira-Segade, Ulysse; Montagnac, Gilles; Daniel, Isabelle

    2018-04-05

    Icy environments may have been common on early Earth due to the faint young sun. Previous studies have proposed that the formation of large icy bodies in the early ocean could concentrate the building blocks of life in eutectic fluids and, therefore, facilitate the polymerization of monomers. This hypothesis is based on the untested assumption that organic molecules are virtually incompatible in ice Ih (hexagonal ice). In this study, we conducted freezing experiments to explore the partitioning behavior of selected amino acids (AAs; glycine, l-alanine, l-proline, and l-phenylalanine) between ice Ih and aqueous solutions analogous to seawater. We allowed ice crystals to grow slowly from a few seeds in equilibrium with the solution and used Raman spectroscopy to analyze in situ the relative concentrations of AAs in the ice and aqueous solution. During freezing, there was no precipitation of AA crystals, indicating that the concentrations in solution never reached their solubility limit, even when the droplet was mostly frozen. Analyses of the Raman spectra of the ice and eutectic solution suggested that considerable amounts of AAs existed in the ice phase with partition coefficients varying between 0.2 and 0.5. These observations imply little incompatibility of AAs in ice Ih during the freezing of the solutions, rendering the concentration hypothesis in a eutectic system unwarranted. However, incorporation into ice Ih could protect AAs from decomposition or racemization and significantly improve the efficiency of extraterrestrial transport of small organics. Therefore, this study supports the hypothesis of extraterrestrial delivery of organic molecules in icy comets and asteroids to the primitive Earth as suggested by an increasing number of independent observations. Key Words: Ice Ih-Partition coefficient-Amino acids-Polymerization-Extraterrestrial transport of organics. Astrobiology 18, 381-392.

  20. L-aspartic acid transport by cat erythrocytes

    International Nuclear Information System (INIS)

    Chen, C.W.; Preston, R.L.

    1986-01-01

    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 3 H-L-asp (typically 2μM) was measured in washed RBCs incubated for 60 s at 37 0 C in medium containing 140 mM NaCl, 5 mM Kcl, 2 mM CaCl 2 , 15 mM MOPS pH 7.4, 5 mM glucose, and 14 C-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 -1 h -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

  1. Compatibility of amino acids in ice Ih and high-pressure phases: implications for the origin of life

    Science.gov (United States)

    Hao, J.; Giovenco, E.; Pedreira-Segade, U.; Montagnac, G.; Daniel, I.

    2017-12-01

    Icy environments may have been common on the early Earth due to the faint young sun. Previous studies have proposed that the formation of large icy bodies in the early ocean could concentrate the building blocks of life in eutectic fluids and therefore facilitate the polymerization of monomers. This hypothesis is based on the untested assumption that organic molecules are virtually incompatible in ice Ih. In this study, we conducted freezing experiments to explore the partitioning behavior of selected amino acids (glycine, L-alanine, L-proline, and L-phenylalanine) between ice Ih and aqueous solutions analogous to seawater. We let ice crystals grow slowly from a few seeds in equilibrium with the solution and used Raman spectroscopy to analyze in situ the relative concentrations of amino acids in the ice and aqueous solution. During freezing, there was no precipitation of amino acid crystals, indicating that the concentrations in solution never reached their solubility limit, even when the droplet was mostly frozen. Analyses of the Raman spectra of ice and eutectic solution showed that considerable amounts of amino acids existed in the ice phase with partition coefficients ranging between 0.2 and 0.5. This study also explored the partitioning of amino acids between other phases of ice (ice VI and ice VII) and solutions at high pressures and observed similar results. These observations implied little incompatibility of amino acids in ice during the freezing of the solutions, rendering the hypothesis of a cold origin of life unwarranted. However, incorporation into ice could significantly improve the efficiency of extraterrestrial transport of small organics. Therefore, this study supports the hypothesis of extraterrestrial delivery of organic molecules in the icy comets and asteroids to the primitive Earth as suggested by an increasing number of independent observations.

  2. Characterization of molecular determinants of the conformational stability of macrophage migration inhibitory factor: leucine 46 hydrophobic pocket.

    Directory of Open Access Journals (Sweden)

    Farah El-Turk

    Full Text Available Macrophage Migration Inhibitory Factor (MIF is a key mediator of inflammatory responses and innate immunity and has been implicated in the pathogenesis of several inflammatory and autoimmune diseases. The oligomerization of MIF, more specifically trimer formation, is essential for its keto-enol tautomerase activity and probably mediates several of its interactions and biological activities, including its binding to its receptor CD74 and activation of certain signaling pathways. Therefore, understanding the molecular factors governing the oligomerization of MIF and the role of quaternary structure in modulating its structural stability and multifunctional properties is crucial for understanding the function of MIF in health and disease. Herein, we describe highly conserved intersubunit interactions involving the hydrophobic packing of the side chain of Leu46 onto the β-strand β3 of one monomer within a hydrophobic pocket from the adjacent monomer constituted by residues Arg11, Val14, Phe18, Leu19, Val39, His40, Val41, Val42, and Pro43. To elucidate the structural significance of these intersubunit interactions and their relative contribution to MIF's trimerization, structural stability and catalytic activity, we generated three point mutations where Leu46 was replaced by glycine (L46G, alanine (L46A and phenylalanine (L46F, and their structural properties, stability, oligomerization state, and catalytic activity were characterized using a battery of biophysical methods and X-ray crystallography. Our findings provide new insights into the role of the Leu46 hydrophobic pocket in stabilizing the conformational state of MIF in solution. Disrupting the Leu46 hydrophobic interaction perturbs the secondary and tertiary structure of the protein but has no effect on its oligomerization state.

  3. 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. © 2016 American Society for Nutrition.

  4. Genetics of Amino Acid Taste and Appetite123

    Science.gov (United States)

    Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Beauchamp, Gary K

    2016-01-01

    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

  5. NMR spectra of PB2 627, the RNA-binding domain in influenza A virus RNA polymerase that contains the pathogenicity factor lysine 627, and improvement of the spectra by small osmolytes

    Directory of Open Access Journals (Sweden)

    Yusuke S. Kato

    2017-12-01

    Full Text Available The influenza A virus, which has an RNA genome, requires RNA-dependent RNA polymerase for transcription and replication. The polymerase is comprised of the subunits PA, PB1, and PB2. The C-terminal RNA-binding domain in PB2 contains lysine 627 (PB2 627, which is associated with pathogenicity and host range. However, the structure and molecular mechanism of PB2 627 in solution remain obscure. Here, we investigated PB2 627 in solution by nuclear magnetic resonance (NMR and detected inhomogeneity in the intensities of backbone amide proton signals due to local fluctuations in structure. To characterize the effects of chemical chaperones on spectral data and improve the data quality, we tested 20 different additives, including L-arginine L-glutamate salt, (L-arginine2SO4, glycerol, β-octylglucoside, 3-[(3-cholamidopropyl dimethylammonio]-1-propanesulfonate, Na2SO4, 1,5-diaminopentane, 1,4-diaminobutane, trehalose, sucrose, glycine, trimethylamine N-oxide, β-alanine, L-α-alanine, hydroxyectoine, betaine, L-proline, and non-detergent sulfobetaine 195, 201, and 256. We evaluated the quality of the resulting spectra by calculating the standard deviation and average of the ratio of signal intensities to noise level of amide peaks, as well as the ratio of the standard deviation to the average. NMR-profile analysis revealed diverse effects of additives on the dynamic properties of PB2 627. Based on such criteria, we found that small osmolytes such as glycine and L-α-alanine reduced structural fluctuations and improved the quality of spectral data, which is likely to facilitate a detailed NMR-based structural analysis. The methodology developed here may also be more generally useful for evaluating the effects of chemical chaperones on the structural integrity of proteins.

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

    International Nuclear Information System (INIS)

    Held, Christoph; Reschke, Thomas; Müller, Rainer; Kunz, Werner; Sadowski, Gabriele

    2014-01-01

    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 NO 3 [−] (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 + , NH 4 + , Cl − , Br − , I − , NO 3 − , and SO 4 2− 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

  7. Design, characterization, teratogenicity testing, antibacterial, antifungal and DNA interaction of few high spin Fe(II) Schiff base amino acid complexes

    Science.gov (United States)

    Abdel-Rahman, Laila H.; El-Khatib, Rafat M.; Nassr, Lobna A. E.; Abu-Dief, Ahmed M.; Lashin, Fakhr El-Din

    2013-07-01

    In this study, new Fe(II) Schiff base amino acid chelates derived from the condensation of o-hydroxynaphthaldehyde with L-alanine, L-phenylalanine, L-aspartic acid, L-histidine and L-arginine were synthesized and characterized via elemental, thermogravimetric analysis, molar conductance, IR, electronic, mass spectra and magnetic moment measurements. The stoichiometry and the stability constants of the complexes were determined spectrophotometrically. Correlation of all spectroscopic data suggested that Schiff bases ligands exhibited tridentate with ONO sites coordinating to the metal ions via protonated phenolic-OH, azomethine-N and carboxylate-O with the general formulae [Fe(HL)2]·nH2O. But in case of L-histidine, the ligand acts as tetradentate via deprotonated phenolic-OH, azomethine-N, carboxylate-O and N-imidazole ring ([FeL(H2O)2]·2H2O), where HL = mono anion and L = dianion of the ligand. The structure of the prepared complexes is suggested to be octahedral. The prepared complexes were tested for their teratogenicity on chick embryos and found to be safe until a concentration of 100 μg/egg with full embryos formation. Moreover, the interaction between CT-DNA and the investigated complexes were followed by spectrophotometric and viscosity measurements. It was found that, the prepared complexes bind to DNA via classical intercalative mode and showed a different DNA activity with the sequence: nhi > nari > nali > nasi > nphali. Furthermore, the free ligands and their complexes are screened for their in vitro antibacterial and antifungal activity against three types of bacteria, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus and three types of anti fungal cultures, Penicillium purpurogenium, Aspergillus flavus and Trichotheium rosium in order to assess their antimicrobial potential. The results show that the metal complexes are more reactive with respect to their corresponding Schiff base amino acid ligands.

  8. A Polyphasic Approach for Phenotypic and Genetic Characterization of the Fastidious Aquatic Pathogen Francisella noatunensis subsp. orientalis

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    José G. Ramírez-Paredes

    2017-12-01

    Full Text Available Francisella noatunensis subsp. orientalis (Fno is the causative agent of piscine francisellosis, an emerging infectious disease in Asia and Latin America. In this study two outbreaks of francisellosis were diagnosed in the UK on the basis of histopathology, electron microscopy, PCR, bacterial isolation and fulfillment of Koch's postulates. Furthermore, a phenotypic fingerprint based on biochemical analyses, metabolic activity, chemotaxonomic composition, and antimicrobial assays was generated for the novel isolates, the Fno type strain Ehime-1 from Asia and other Fno from Latin America. The genetic relatedness between the novel Fno and other Francisellaceae species was investigated by sequencing and comparing the 16SrRNA gene, 8 housekeeping genes (individually and concatenated and the 16SrRNA-ITS-23SrRNA sequence. The phenotypic profiling indicated a high degree of similarity among the Fno strains as all were able to metabolize dextrin, N-acetyl-D glucosamine, D-fructose, α-D-glucose, D-mannose, methyl pyruvate, acetic acid, α-keto butyric acid, L-alaninamide, L-alanine, L-alanylglycine, L-asparagine, L-glutamic acid, L-proline, L-serine, L-threonine, inosine, uridine, glycerol, D L-α-glycerol phosphate, glucose-1-phosphate, and glucose-6-phosphate. The chemotaxonomic analyses indicated that 24:1 (20.3%, 18:1n-9 (16.9%, 24:0 (13.1% 14:0 (10.9%, 22:0 (7.8%, 16:0 (7.6%, and 18:0 (5.5% were the predominant structural fatty acids in Fno. The antimicrobial assays showed little variation between the isolates and high susceptibility to enrofloxacin, gentamicin, neomycin, streptomycin, amikacin, ciprofloxacin, gatifloxacin, nitrofurantoin, tobramycin, kanamycin, tetracycline, oxytetracycline, florfenicol, oxolinic acid, and streptomycin in all the Fno analyzed. In all the phylogenetic trees the Fno strains clustered together in independent branches confirming a high degree of homogeneity. Interestingly in five of the 11 trees i.e., mutS, putA, rpo

  9. Role of L-alanine for redox self-sufficient amination of alcohols.

    Science.gov (United States)

    Klatte, Stephanie; Wendisch, Volker F

    2015-01-23

    In white biotechnology biocatalysis represents a key technology for chemical functionalization of non-natural compounds. The plasmid-born overproduction of an alcohol dehydrogenase, an L-alanine-dependent transaminase and an alanine dehydrogenase allows for redox self-sufficient amination of alcohols in whole cell biotransformation. Here, conditions to optimize the whole cell biocatalyst presented in (Bioorg Med Chem 22:5578-5585, 2014), and the role of L-alanine for efficient amine functionalization of 1,10-decanediol to 1,10-diaminodecane were analyzed. The enzymes of the cascade for amine functionalization of alcohols were characterized in vitro to find optimal conditions for an efficient process. Transaminase from Chromobacterium violaceum, TaCv, showed three-fold higher catalytic efficiency than transaminase from Vibrio fluvialis, TaVf, and improved production at 37°C. At 42°C, TaCv was more active, which matched thermostable alcohol dehydrogenase and alanine dehydrogenase and improved the 1,10-diaminodecane production rate four-fold. To study the role of L-alanine in the whole cell biotransformation, the L-alanine concentration was varied and 1,10.diaminodecane formation tested with constant 10 mM 1,10- decanediol and 100 mM NH4Cl. Only 5.6% diamine product were observed without added L-alanine. L-alanine concentrations equimolar to that of the alcohol enabled for 94% product formation but higher L-alanine concentrations allowed for 100% product formation. L-alanine was consumed by the E. coli biocatalyst, presumably due to pyruvate catabolism since up to 16 mM acetate accumulated. Biotransformation employing E. coli strain YYC202/pTrc99a-ald-adh-ta Cv, which is unable to catabolize pyruvate, resulted in conversion with a selectivity of 42 mol-%. Biotransformation with E. coli strains only lacking pyruvate oxidase PoxB showed similar reduced amination of 1,10-decanediol indicating that oxidative decarboxylation of pyruvate to acetate by PoxB is primarily

  10. Expression of the alaE gene is positively regulated by the global regulator Lrp in response to intracellular accumulation of l-alanine in Escherichia coli.

    Science.gov (United States)

    Ihara, Kohei; Sato, Kazuki; Hori, Hatsuhiro; Makino, Yumiko; Shigenobu, Shuji; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2017-04-01

    The alaE gene in Escherichia coli encodes an l-alanine exporter that catalyzes the active export of l-alanine using proton electrochemical potential. In our previous study, alaE expression was shown to increase in the presence of l-alanyl-l-alanine (Ala-Ala). In this study, the global regulator leucine-responsive regulatory protein (Lrp) was identified as an activator of the alaE gene. A promoter less β-galactosidase gene was fused to an alaE upstream region (240 nucleotides). Cells that were lacZ-deficient and harbored this reporter plasmid showed significant induction of β-galactosidase activity (approximately 17-fold) in the presence of 6 mM l-alanine, l-leucine, and Ala-Ala. However, a reporter plasmid possessing a smaller alaE upstream region (180 nucleotides) yielded transformants with strikingly low enzyme activity under the same conditions. In contrast, lrp-deficient cells showed almost no β-galactosidase induction, indicating that Lrp positively regulates alaE expression. We next performed an electrophoretic mobility shift assay (EMSA) and a DNase I footprinting assay using purified hexahistidine-tagged Lrp (Lrp-His). Consequently, we found that Lrp-His binds to the alaE upstream region spanning nucleotide -161 to -83 with a physiologically relevant affinity (apparent K D , 288.7 ± 83.8 nM). Furthermore, the binding affinity of Lrp-His toward its cis-element was increased by l-alanine and l-leucine, but not by Ala-Ala and d-alanine. Based on these results, we concluded that the gene expression of the alaE is regulated by Lrp in response to intracellular levels of l-alanine, which eventually leads to intracellular homeostasis of l-alanine concentrations. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  11. Secretion of d-alanine by Escherichia coli.

    Science.gov (United States)

    Katsube, Satoshi; Sato, Kazuki; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2016-07-01

    Escherichia coli has an l-alanine export system that protects the cells from toxic accumulation of intracellular l-alanine in the presence of l-alanyl-l-alanine (l-Ala-l-Ala). When a DadA-deficient strain was incubated with 6.0 mM l-Ala-l-Ala, we detected l-alanine and d-alanine using high-performance liquid chromatography (HPLC) analysis at a level of 7.0 mM and 3.0 mM, respectively, after 48 h incubation. Treatment of the culture supernatant with d-amino acid oxidase resulted in the disappearance of a signal corresponding to d-alanine. Additionally, the culture supernatant enabled a d-alanine auxotroph to grow without d-alanine supplementation, confirming that the signal detected by HPLC was authentic d-alanine. Upon introduction of an expression vector harbouring the alanine racemase genes, alr or dadX, the extracellular level of d-alanine increased to 11.5 mM and 8.5 mM, respectively, under similar conditions, suggesting that increased metabolic flow from l-alanine to d-alanine enhanced d-alanine secretion. When high-density DadA-deficient cells preloaded with l-Ala-l-Ala were treated with 20 µM carbonyl cyanide m-chlorophenyl hydrazone (CCCP), secretion of both l-alanine and d-alanine was enhanced ~twofold compared with that in cells without CCCP treatment. In contrast, the ATPase inhibitor dicyclohexylcarbodiimide did not exert such an effect on the l-alanine and d-alanine secretion. Furthermore, inverted membrane vesicles prepared from DadA-deficient cells lacking the l-alanine exporter AlaE accumulated [3H]D-alanine in an energy-dependent manner. This energy-dependent accumulation of [3H]D-alanine was strongly inhibited by CCCP. These results indicate that E. coli has a transport system(s) that exports d-alanine and that this function is most likely modulated by proton electrochemical potential.

  12. Optimum conditions for prebiotic evolution in extraterrestrial environments

    Science.gov (United States)

    Abbas, Ousama H.

    The overall goal of the dissertation was to devise synthetic pathways leading to the production of peptides and amino acids from smaller organic precursors. To this end, eight different zeolites were tested in order to determine their catalytic potential in the conversion of amino acids to peptides. The zeolites tested were either synthetic or naturally occurring. Acidic solutions of amino acids were prepared with or without zeolites and their reactivity was monitored over a four-week time interval. The kinetics and feasibility of peptide synthesis from selected amino acid combinations was investigated via the paper chromatography technique. Nine different amino acids were tested. The nature and extent of product were measured at constant time intervals. It was found that two ZSM-5 synthetic zeolites as well as the Fisher Scientific zeolite mix without alumina salts may have a catalytic potential in the conversion of amino acids to peptides. The conversion was verified by matching the paper chromatogram of the experimental product with that of a known peptide. The experimental results demonstrate that the optimum solvent system for paper chromatographic analysis of the zeolite-catalyzed self-assembly of the amino acids L-aspartic acid, L- asparagine, L-histidine, and L-serine is a 50:50 mixture of 1-butanol and acetone by volume. For the amino acids L-alanine, L-glycine, and L-valine, the optimum solvent was found to be a 30:70 mixture of ammonia and propanol by volume. A mathematical model describing the distance traveled (spot position) versus reaction time was constructed for the zeolite-catalyzed conversion of L- leucine and L-tyrosine and was found to approximately follow the function f(t) = 25 ln t. Two case studies for prebiotic synthesis leading to the production of amino acids or peptides in extraterrestrial environments were discussed: one involving Saturn's moon Titan, and the other involving Jupiter's moon Europa. In the Titan study, it was determined

  13. Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis.

    Science.gov (United States)

    Krawczyk, Antonina O; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H J; Kuipers, Oscar P; Eijlander, Robyn T

    2017-04-01

    Spore heat resistance, germination, and outgrowth are problematic bacterial properties compromising food safety and quality. Large interstrain variation in these properties makes prediction and control of spore behavior challenging. High-level heat resistance and slow germination of spores of some natural Bacillus subtilis isolates, encountered in foods, have been attributed to the occurrence of the spoVA 2mob operon carried on the Tn 1546 transposon. In this study, we further investigate the correlation between the presence of this operon in high-level-heat-resistant spores and their germination efficiencies before and after exposure to various sublethal heat treatments (heat activation, or HA), which are known to significantly improve spore responses to nutrient germinants. We show that high-level-heat-resistant spores harboring spoVA 2mob required higher HA temperatures for efficient germination than spores lacking spoVA 2mob The optimal spore HA requirements additionally depended on the nutrients used to trigger germination, l-alanine (l-Ala), or a mixture of l-asparagine, d-glucose, d-fructose, and K + (AGFK). The distinct HA requirements of these two spore germination pathways are likely related to differences in properties of specific germinant receptors. Moreover, spores that germinated inefficiently in AGFK contained specific changes in sequences of the GerB and GerK germinant receptors, which are involved in this germination response. In contrast, no relation was found between transcription levels of main germination genes and spore germination phenotypes. The findings presented in this study have great implications for practices in the food industry, where heat treatments are commonly used to inactivate pathogenic and spoilage microbes, including bacterial spore formers. IMPORTANCE This study describes a strong variation in spore germination capacities and requirements for a heat activation treatment, i.e., an exposure to sublethal heat that increases

  14. ApoSOD1 lacking dismutase activity neuroprotects motor neurons exposed to beta-methylamino-L-alanine through the Ca2+/Akt/ERK1/2 prosurvival pathway

    Science.gov (United States)

    Petrozziello, Tiziana; Secondo, Agnese; Tedeschi, Valentina; Esposito, Alba; Sisalli, MariaJosè; Scorziello, Antonella; Di Renzo, Gianfranco; Annunziato, Lucio

    2017-01-01

    Amyotrophic lateral sclerosis (ALS) is a severe human adult-onset neurodegenerative disease affecting lower and upper motor neurons. In >20% of cases, the familial form of ALS is caused by mutations in the gene encoding Cu,Zn-superoxide dismutase (SOD1). Interestingly, administration of wild-type SOD1 to SOD1G93A transgenic rats ameliorates motor symptoms through an unknown mechanism. Here we investigated whether the neuroprotective effects of SOD1 are due to the Ca2+-dependent activation of such prosurvival signaling pathway and not to its catalytic activity. To this aim, we also examined the mechanism of neuroprotective action of ApoSOD1, the metal-depleted state of SOD1 that lacks dismutase activity, in differentiated motor neuron-like NSC-34 cells and in primary motor neurons exposed to the cycad neurotoxin beta-methylamino-L-alanine (L-BMAA). Preincubation of ApoSOD1 and SOD1, but not of human recombinant SOD1G93A, prevented cell death in motor neurons exposed to L-BMAA. Moreover, ApoSOD1 elicited ERK1/2 and Akt phosphorylation in motor neurons through an early increase of intracellular Ca2+ concentration ([Ca2+]i). Accordingly, inhibition of ERK1/2 by siMEK1 and PD98059 counteracted ApoSOD1- and SOD1-induced neuroprotection. Similarly, transfection of the dominant-negative form of Akt in NSC-34 motor neurons and treatment with the selective PI3K inhibitor LY294002 prevented ApoSOD1- and SOD1-mediated neuroprotective effects in L-BMAA-treated motor neurons. Furthermore, ApoSOD1 and SOD1 prevented the expression of the two markers of L-BMAA-induced ER stress GRP78 and caspase-12. Collectively, our data indicate that ApoSOD1, which is devoid of any catalytic dismutase activity, exerts a neuroprotective effect through an early activation of Ca2+/Akt/ERK1/2 pro-survival pathway that, in turn, prevents ER stress in a neurotoxic model of ALS. PMID:28085149

  15. Characterization of germination receptors of Bacillus cereus ATCC 14579.

    Science.gov (United States)

    Hornstra, Luc M; de Vries, Ynte P; Wells-Bennik, Marjon H J; de Vos, Willem M; Abee, Tjakko

    2006-01-01

    Specific amino acids, purine ribonucleosides, or a combination of the two is required for efficient germination of endospores of Bacillus cereus ATCC 14579. A survey including 20 different amino acids showed that l-alanine, l-cysteine, l-threonine, and l-glutamine are capable of initiating the germination of endospores of B. cereus ATCC 14579. In addition, the purine ribonucleosides inosine and adenosine can trigger germination of the spores. Advanced annotation of the B. cereus ATCC 14579 genome revealed the presence of seven putative germination (ger) operons, termed gerG, gerI, gerK, gerL, gerQ, gerR, and gerS. To determine the role of the encoded putative receptors in nutrient-induced germination, disruption mutants were constructed by the insertion of pMUTIN4 into each of the seven operons. Four of the seven mutants were affected in the germination response to amino acids or purine ribonucleosides, whereas no phenotype could be attributed to the mutants with disrupted gerK, gerL, and gerS loci. The strain with a disrupted gerR operon was severely hampered in the ability to germinate: germination occurred in response to l-glutamine but not in the presence of any of the other amino acids tested. The gerG mutant showed significantly reduced l-glutamine-induced germination, which points to a role of this receptor in the l-glutamine germination signaling pathway. gerR, gerI, and gerQ mutants showed reduced germination rates in the presence of inosine, suggesting a role for these operons in ribonucleoside signaling. Efficient germination by the combination of l-glutamine and inosine was shown to involve the gerG and gerI operons, since the germination of mutants lacking either one of these receptors was significantly reduced. Germination triggered by the combination of l-phenylalanine and inosine was lost in the gerI mutant, indicating that both molecules are effective at the GerI receptor.

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

    Directory of Open Access Journals (Sweden)

    Noureddine Bouras

    2016-04-01

    Full Text Available 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 (NH42SO4] 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 ± 4.46 μg g− 1, 43.07 ± 23.39 μg g− 1 and 28.91 ± 4.64 μg 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 ± 4.71 μg g− 1 of medium and TS93-71B (27.03 ± 4.09 μg g− 1 of medium on synthetic medium supplemented with l-alanine. The highest concentrations of catenarin (174.54 ± 14.46 μg g− 1 and 104.87 ± 6.13 μg 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 ± 0.36 μg 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.

  17. Transport of D-[1-14C]-amino acids into Chinese hamster ovary (CHO-K1) cells: implications for use of labeled D-amino acids as molecular imaging agents

    International Nuclear Information System (INIS)

    Shikano, Naoto; Nakajima, Syuichi; Kotani, Takashi; Ogura, Masato; Sagara, Jun-ichi; Iwamura, Yukio; Yoshimoto, Mitsuyoshi; Kubota, Nobuo; Ishikawa, Nobuyoshi; Kawai, Keiichi

    2007-01-01

    Introduction: The fact that D-amino acids have been found in various tissues and are involved in various functions is a clue to how to develop new imaging agents. We examined D-amino acid transport mechanisms in Chinese hamster ovary (CHO-K1) cells because CHO-K1 cells are widely used in biomedical studies and are thought to be useful for expression of genes involved in metabolism of D-amino acids. Methods: Uptake experiments were performed. CHO-K1 cells cultured in 60-mm plastic culture dishes under ordinary culture conditions were incubated with 18.5 kBq of radiolabeled amino acid in 2 ml of phosphate-buffered-saline-based uptake solution at 37 o C. The following radiolabeled amino acid tracers were used: D-[1- 14 C]-alanine, L-[1- 14 C]-alanine, D-[1- 14 C]-serine, L-[1- 14 C]-serine, D-[1- 14 C]-methionine, L-[1- 14 C]-methionine, D-[1- 14 C]-phenylalanine, L-[1- 14 C]-phenylalanine, D-[1- 14 C]-leucine, L-[1- 14 C]-leucine, D-[1- 14 C]-valine, L-[1- 14 C]-valine, D-[1- 14 C]-tyrosine, L-[1- 14 C]-tyrosine, D-[1- 14 C]-glutamic acid, L-[1- 14 C]-glutamic acid, D-[1- 14 C]-lysine, L-[1- 14 C]-lysine, D-[1- 14 C]-arginine and L-[1- 14 C]-arginine. We tested the inhibitory effects of the following compounds (1.0 mM) on transport: 2-(methylamino)isobutyric acid (a specific inhibitor of system A, in Na + -containing uptake solution) and 2-amino-bicyclo[2,2,1]heptane-2-carboxylic acid (a specific inhibitor of system L, in Na + -free uptake solution). Results: D-[1- 14 C]-methionine, D-[1- 14 C]-phenylalanine and D-[1- 14 C]-tyrosine accumulated mainly via system L. D-[1- 14 C]-alanine and D-[1- 14 C]-serine accumulated primarily via system ASC. High uptake of D-[1- 14 C]-alanine, D-[1- 14 C]-methionine, D-[1- 14 C]-phenylalanine and D-[1- 14 C]-leucine was observed. The uptake of radiolabeled serine, valine, tyrosine, glutamic acid and arginine into CHO-K1 was highly stereoselective for L-isomers. Conclusions: We observed high uptake of D-[1- 14 C]-alanine via system