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Sample records for single tryptophan residue

  1. Modification of a single tryptophan residue in human Cu,Zn-superoxide dismutase by peroxynitrite in the presence of bicarbonate.

    Science.gov (United States)

    Yamakura, F; Matsumoto, T; Fujimura, T; Taka, H; Murayama, K; Imai, T; Uchida, K

    2001-07-09

    Human recombinant Cu,Zn-SOD was reacted with peroxynitrite in a reaction mixture containing 150 mM potassium phosphate buffer (pH 7.4) 25 mM sodium bicarbonate, and 0.1 mM diethylenetriamine pentaacetic acid. Disappearance of fluorescence emission at 350 nm, which could be attributed to modification of a single tryptophan residue, was observed in the modified enzyme with a pH optimum of around 8.4. A fluorescence decrease with the same pH optimum was also observed without sodium bicarbonate, but with less efficiency. Amino acid contents of the modified enzyme showed no significant difference in all amino acids except the loss of a single tryptophan residue of the enzyme. The peroxynitrite-modified enzyme showed an increase in optical absorption around 350 nm and 30% reduced enzyme activity based on the copper contents. The modified enzyme showed the same electron paramagnetic resonance spectrum as that of the control enzyme. The modified Cu,Zn-SOD showed a single protein band in sodium dodecyl sulfate--polyacrylamide gel electrophoresis (SDS--PAGE) and five protein bands in non-denaturing PAGE. From this evidence, we conclude that nitration and/or oxidation of the single tryptophan 32 and partial inactivation of the enzyme activity of Cu,Zn-SOD is caused by a peroxynitrite-carbon dioxide adduct without perturbation of the active site copper integrity.

  2. Room temperature phosphorescence study on the structural flexibility of single tryptophan containing proteins

    Science.gov (United States)

    Kowalska-Baron, Agnieszka; Gałęcki, Krystian; Wysocki, Stanisław

    2015-01-01

    In this study, we have undertaken efforts to find correlation between phosphorescence lifetimes of single tryptophan containing proteins and some structural indicators of protein flexibility/rigidity, such as the degree of tryptophan burial or its exposure to solvent, protein secondary and tertiary structure of the region of localization of tryptophan as well as B factors for tryptophan residue and its immediate surroundings. Bearing in mind that, apart from effective local viscosity of the protein/solvent matrix, the other factor that concur in determining room temperature tryptophan phosphorescence (RTTP) lifetime in proteins is the extent of intramolecular quenching by His, Cys, Tyr and Trp side chains, the crystallographic structures derived from the Brookhaven Protein Data Bank were also analyzed concentrating on the presence of potentially quenching amino acid side chains in the close proximity of the indole chromophore. The obtained results indicated that, in most cases, the phosphorescence lifetimes of tryptophan containing proteins studied tend to correlate with the above mentioned structural indicators of protein rigidity/flexibility. This correlation is expected to provide guidelines for the future development of phosphorescence lifetime-based method for the prediction of structural flexibility of proteins, which is directly linked to their biological function.

  3. Introduction of a unique tryptophan residue into various positions of Bacillus licheniformis DnaK.

    Science.gov (United States)

    Chen, Bo-En; Lin, Min-Guan; Lo, Huei-Fen; Wang, Tzu-Fan; Chi, Meng-Chun; Lin, Long-Liu

    2013-01-01

    Site-directed mutagenesis together with biochemical and biophysical techniques were used to probe effects of single-tryptophan-incorporated mutations on a bacterial molecular chaperone, Bacillus licheniformis DnaK (BlDnaK). Specifically, five phenylalanine residues (Phe(120), Phe(174), Phe(186), Phe(378) and Phe(396)) of BlDnaK were individually replaced by single tryptophans, thus creating site-specific probes for the fluorescence analysis of the protein. The steady-state ATPase activity for BlDnaK, F120W, F174W, F186W, F378W, and F396W was determined to be 76.01, 52.82, 25.32, 53.31, 58.84, and 47.53 nmol Pi/min/mg, respectively. Complementation test revealed that the single mutation at codons 120, 186, and 378 of the dnaK gene still allowed an Escherichia coli dnaK756-Ts strain to grow at a stringent temperature of 44°C. Simultaneous addition of co-chaperones and NR-peptide did not synergistically stimulate the ATPase activity of F174W and F396W, and these two proteins were unable to assist the refolding of GdnHCl-denatured luciferase. The heat-induced denaturation of all variants could be fitted adequately to a three-state model, in agreement with the observation for the wild-type protein. By CD spectral analysis, GdnHCl-induced unfolding transition for BlDnaK was 1.51 M corresponding to ΔG(N-U) of 1.69 kcal/mol; however, the transitions for mutant proteins were 1.07-1.55 M equivalent to ΔG(N-U) of 0.94-2.93 kcal/mol. The emission maximum of single-tryptophan-incorporated variants was in the range of 333.2-335.8 nm. Acrylamide quenching analysis showed that the mutant proteins had a dynamic quenching constant of 3.0-4.2 M(-1). Taken together, these results suggest that the molecular properties of BlDnaK have been significantly changed upon the individual replacement of selected phenylalanine residues by tryptophan. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. REPLACEMENT OF TRYPTOPHAN RESIDUES IN HALOALKANE DEHALOGENASE REDUCES HALIDE BINDING AND CATALYTIC ACTIVITY

    NARCIS (Netherlands)

    KENNES, C; PRIES, F; KROOSHOF, GH; BOKMA, E; Kingma, Jacob; JANSSEN, DB

    1995-01-01

    Haloalkane dehalogenase catalyzes the hydrolytic cleavage of carbon-halogen bonds in short-chain haloalkanes. Two tryptophan residues of the enzyme (Trp125 and Trp175) form a halide-binding site in the active-site cavity, and were proposed to play a role in catalysis. The function of these residues

  5. Combined Role of Two Tryptophane Residues of α-Factor Pheromone

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Eun Young [Yeungnam Univ., Gyungsan (Korea, Republic of); Hong, Nam Joo [Seoul National Univ., Seoul (Korea, Republic of)

    2013-02-15

    Amide analogs of tridecapeptide α-factor (WHWLQLKPGQPMYCONH{sub 2}) of Saccharomyces cerevisiae, in which Trp at position 1 and 3 were replaced with other residues, were synthesized to ascertain whether cooperative interactions between two Trp residues occurred upon binding with its receptor. Analogs containing Ala or Aib at position 3 of the peptide [Ala{sup 3}]α-factor amide (2) and [Aib{sup 3}]α-factor amide (5) exhibited greater decreases in bioactivity than analogs with same residue at position one [Ala{sup 1}]α-factor amide (1) and [Aib{sup 1}]α-factor amide (4), reflecting that Trp{sup 3} may plays more important role than Trp{sup 1} for agonist activity. Analogs containing Ala or Aib in both position one and three 3, 6 exhibited complete loss of bioactivity, emphasizing both the essential role and the combined role of two indole rings for triggering cell signaling. In contrast, double substituted analog with D-Trp in both positions 9 exhibited greater activity than single substituted analog with D-Trp 8 or deleted analog 7, reflecting the combined contribution of two tryptophane residues of α-factor ligand to activation of Ste2p through interaction with residue Tyr{sup 266} and importance of the proper parallel orientation of two indole rings for efficient triggering of signal G protein coupled activation. Among ten amide analogs, [Ala{sup 1,3}]α-factor amide (3), [Aib{sup 1,3}]α-factor amide (6), [D-Trp{sup 3}]α-factor amide (8) and [des-Trp{sup 1},Phe{sup 3}]α-factor amide (10) were found to have antagonistic activity. Analogs 3 and 6 showed greater antagonistic activity than analogs 8 and 10.

  6. Combined Role of Two Tryptophane Residues of α-Factor Pheromone

    International Nuclear Information System (INIS)

    Hong, Eun Young; Hong, Nam Joo

    2013-01-01

    Amide analogs of tridecapeptide α-factor (WHWLQLKPGQPMYCONH 2 ) of Saccharomyces cerevisiae, in which Trp at position 1 and 3 were replaced with other residues, were synthesized to ascertain whether cooperative interactions between two Trp residues occurred upon binding with its receptor. Analogs containing Ala or Aib at position 3 of the peptide [Ala 3 ]α-factor amide (2) and [Aib 3 ]α-factor amide (5) exhibited greater decreases in bioactivity than analogs with same residue at position one [Ala 1 ]α-factor amide (1) and [Aib 1 ]α-factor amide (4), reflecting that Trp 3 may plays more important role than Trp 1 for agonist activity. Analogs containing Ala or Aib in both position one and three 3, 6 exhibited complete loss of bioactivity, emphasizing both the essential role and the combined role of two indole rings for triggering cell signaling. In contrast, double substituted analog with D-Trp in both positions 9 exhibited greater activity than single substituted analog with D-Trp 8 or deleted analog 7, reflecting the combined contribution of two tryptophane residues of α-factor ligand to activation of Ste2p through interaction with residue Tyr 266 and importance of the proper parallel orientation of two indole rings for efficient triggering of signal G protein coupled activation. Among ten amide analogs, [Ala 1,3 ]α-factor amide (3), [Aib 1,3 ]α-factor amide (6), [D-Trp 3 ]α-factor amide (8) and [des-Trp 1 ,Phe 3 ]α-factor amide (10) were found to have antagonistic activity. Analogs 3 and 6 showed greater antagonistic activity than analogs 8 and 10

  7. UVB-induced photoperoxidation of lipids of human low and high density lipoproteins. A possible role of tryptophan residues

    International Nuclear Information System (INIS)

    Salmon, S.; Maziere, J.C.; Santus, R.; Bouchemal, N.; Morliere, P.

    1990-01-01

    Ultraviolet radiation of the UVB region readily destroys tryptophan (Trp) residues of low (LDL) and high (HDL) density lipoproteins. The photooxidation of tryptophan residues is accompanied by peroxidation of low and high density lipoproteins unsaturated fatty acids, as measured by thiobarbituric acid assay. Moreover, low and high density lipoproteins are natural carriers of vitamin E and carotenoids. These two antioxidants are also rapidly bleached by UVB. The UVA radiation promotes neither tryptophan residue destruction nor lipid photoperoxidation. The redox cycling Cu 2+ ions considerably increase lipid photoperoxidation. The synergistic action of photo and auto (Cu 2+ -induced) peroxidation induces marked post-irradiation modifications of apolipoproteins as illustrated by degradation of most tryptophan residues after overnight incubation in the dark of pre-irradiated samples. (author)

  8. Mechanisms of tryptophan adsorption onto single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Zhou Jieping; Tan Jun; Xu Pengshou; Sheng Liusi; Pan Guoqiang

    2011-01-01

    Near edge X-ray absorption fine structure spectroscopy (NEXAFS) and synchrotron radiation photoelectron spectroscopy (SRPES) were employed to investigate the adsorption mechanism of tryptophan (Trp) onto single-walled carbon nanotubes (SWCNTs). The difference of the carbon K-edge NEXAFS spectra between Trp molecules and Trp-adsorbed SWCNTs shows that a significant interaction occurs among the SWCNTs and Trp molecules adsorbed. However, negligible changes in the peak profiles and energy positions of nitrogen K-edge imply that neither of the two nitrogen atoms in Trp molecule is involved in the interface interaction. A change of the shape of the main absorption peak at the oxygen K-edge reveals that O atoms of the C=O or C-O or both are likely involved in the interface interaction. The fact that the peak at about 529 eV at the O K-edge become sharper and stronger demonstrates that the O atom in the C=O participates in the interface interaction, which was confirmed by O1s SRPES spectrum. (authors)

  9. Contribution of tryptophan residues to the combining site of a monoclonal anti dinitrophenyl spin-label antibody

    International Nuclear Information System (INIS)

    Anglister, J.; Bond, M.W.; Frey, T.; Leahy, D.; Levitt, M.; McConnell, H.M.; Rule, G.S.; Tomasello, J.; Whittaker, M.

    1987-01-01

    Two Fab fragments of the monoclonal anti dinitrophenyl (DNP) spin-label antibody AN02 were prepared by recombination of specifically deuterated heavy and light chains. In the recombinant H(I)L(II) all the tyrosines and phenylalanines were perdeuterated as were the tryptophan residues of the heavy chain. In the recombinant H(II)L(I) all the tyrosines and phenylalanines were perdeuterated as were the tryptophan residues of the light chain. Saturation of three resonances of H(I)L(II), assigned to tryptophan protons of the light chain, resulted in magnetization transfer to the aromatic proton at position 6 of the DNP ring and to the CH2 protons of the glycines linked to the DNP in a diamagnetic hapten (DNP-DG). Saturation of three resonances of H(II)L(I) assigned to tryptophan protons of the heavy chain resulted in magnetization transfer to the CH2 protons of the glycines in DNP-DG. From the dependence of the magnetization transfer on the irradiation time, the cross relaxation rates between the involved protons were estimated. The inferred distances between these protons of the hapten and certain tryptophan protons are 3-4 A. It is concluded that in the combining site of AN02 there is one tryptophan from the light chain and one tryptophan from the heavy chain that are very near the hapten. When all tyrosines and phenylalanines were perdeuterated and all tryptophan aromatic protons were deuterated except for the protons at positions 2 and 5, titration of the Fab fragments with variable amounts of paramagnetic hapten showed that one proton from the light chain tryptophan is near (less than 7 A) the unpaired electron and that three other protons are significantly closer than 15 A

  10. Contribution of tryptophan residues to the combining site of a monoclonal anti dinitrophenyl spin-label antibody

    Energy Technology Data Exchange (ETDEWEB)

    Anglister, J.; Bond, M.W.; Frey, T.; Leahy, D.; Levitt, M.; McConnell, H.M.; Rule, G.S.; Tomasello, J.; Whittaker, M.

    1987-09-22

    Two Fab fragments of the monoclonal anti dinitrophenyl (DNP) spin-label antibody AN02 were prepared by recombination of specifically deuterated heavy and light chains. In the recombinant H(I)L(II) all the tyrosines and phenylalanines were perdeuterated as were the tryptophan residues of the heavy chain. In the recombinant H(II)L(I) all the tyrosines and phenylalanines were perdeuterated as were the tryptophan residues of the light chain. Saturation of three resonances of H(I)L(II), assigned to tryptophan protons of the light chain, resulted in magnetization transfer to the aromatic proton at position 6 of the DNP ring and to the CH2 protons of the glycines linked to the DNP in a diamagnetic hapten (DNP-DG). Saturation of three resonances of H(II)L(I) assigned to tryptophan protons of the heavy chain resulted in magnetization transfer to the CH2 protons of the glycines in DNP-DG. From the dependence of the magnetization transfer on the irradiation time, the cross relaxation rates between the involved protons were estimated. The inferred distances between these protons of the hapten and certain tryptophan protons are 3-4 A. It is concluded that in the combining site of AN02 there is one tryptophan from the light chain and one tryptophan from the heavy chain that are very near the hapten. When all tyrosines and phenylalanines were perdeuterated and all tryptophan aromatic protons were deuterated except for the protons at positions 2 and 5, titration of the Fab fragments with variable amounts of paramagnetic hapten showed that one proton from the light chain tryptophan is near (less than 7 A) the unpaired electron and that three other protons are significantly closer than 15 A.

  11. Interfacial Tryptophan Residues: A Role for the Cation-{pi} Effect?

    DEFF Research Database (Denmark)

    Petersen, Frederic Nicolas Rønne; Jensen, Morten Ø.; Helix Nielsen, Claus

    2005-01-01

    Integral membrane proteins are characterized by having a preference for aromatic residues, e.g., tryptophan (W), at the interface between the lipid bilayer core and the aqueous phase. The reason for this is not clear, but it seems that the preference is related to a complex interplay between steric...... between the nitrogen moiety of lipid molecule headgroups and the pi-electron distribution of gramicidin (gA) tryptophan residues (W(9), W(11), W(13), and W(15)) using molecular dynamics (MD) simulations of gA embedded in two hydrated lipid bilayers composed of 1-palmitoyl-2-oleoylphosphatidylethanolamine....... Our criteria for cation-pi interactions are based on distance and angular requirements, and the results from our model suggest that cation-pi interactions are relevant for W(PE)(11), W(PE)(13), W(PE)(15), and, to some extent, W(PC)(11) and W(PC)(13). In our model, W(9)does not seem to engage in cation...

  12. [Environment of tryptophan residues in proteins--a factor for stability to oxidative nitrosylation. I. Analysis of primary structure].

    Science.gov (United States)

    Beda, N V; Nedospasov, A A

    2001-01-01

    Micellar catalysis under aerobic conditions effectively accelerates oxidative nitrosylation because of solubilization of NO and O2 by protein membranes and hydrophobic nuclei. Nitrosylating intermediates NOx (NO2, N2O3, N2O4) form mainly in the hydrophobic phase, and therefore their solubility in aqueous phase is low and hydrolysis is rapid, local concentration of NOx in the hydrophobic phase being essentially higher than in aqueous. Tryptophan is a hydrophobic residue and can nitrosylate with the formation of isomer N-nitrosotryptophans (NOW). Without denitrosylation mechanism, the accumulation of NOW in proteins of NO-synthesizing organisms would be constant, and long-living proteins would contain essential amounts of NOW, which is however not the case. Using Protein Data Bank (more than 78,000 sequences) we investigated the distribution of tryptophan residues environment (22 residues on each side of polypeptide chain) in proteins with known primary structure. Charged and polar residues (D, H, K, N, Q, R, S) are more incident in the immediate surrounding of tryptophan (-6, -5, -2, -1, 1, 2, 4) and hydrophobic residues (A, F, I, L, V, Y) are more rare than in remote positions. Hence, an essential part of tryptophan residues is situated in hydrophilic environment, which decreases the nitrosylation velocity because of lower NOx concentration in aqueous phase and allows the denitrosylation reactions course via nitrosonium ion transfer on nucleophils of functional groups of protein and low-molecular compounds in aqueous phase.

  13. Chemical-modification studies of a unique sialic acid-binding lectin from the snail Achatina fulica. Involvement of tryptophan and histidine residues in biological activity.

    Science.gov (United States)

    Basu, S; Mandal, C; Allen, A K

    1988-01-01

    A unique sialic acid-binding lectin, achatininH (ATNH) was purified in single step from the haemolymph of the snail Achatina fulica by affinity chromatography on sheep submaxillary-gland mucin coupled to Sepharose 4B. The homogeneity was checked by alkaline gel electrophoresis, immunodiffusion and immunoelectrophoresis. Amino acid analysis showed that the lectin has a fairly high content of acidic amino acid residues (22% of the total). About 1.3% of the residues are half-cystine. The glycoprotein contains 21% carbohydrate. The unusually high content of xylose (6%) and fucose (2.7%) in this snail lectin is quite interesting. The protein was subjected to various chemical modifications in order to detect the amino acid residues and carbohydrate residues present in its binding sites. Modification of tyrosine and arginine residues did not affect the binding activity of ATNH; however, modification of tryptophan and histidine residues led to a complete loss of its biological activity. A marked decrease in the fluorescence emission was found as the tryptophan residues of ATNH were modified. The c.d. data showed the presence of an identical type of conformation in the native and modified agglutinin. The modification of lysine and carboxy residues partially diminished the biological activity. The activity was completely lost after a beta-elimination reaction, indicating that the sugars are O-glycosidically linked to the glycoprotein's protein moiety. This result confirms that the carbohydrate moiety also plays an important role in the agglutination property of this lectin. Images Fig. 3. PMID:3140796

  14. Intragenic suppressor of Osiaa23 revealed a conserved tryptophan residue crucial for protein-protein interactions.

    Directory of Open Access Journals (Sweden)

    Jun Ni

    Full Text Available The Auxin/Indole-3-Acetic Acid (Aux/IAA and Auxin Response Factor (ARF are two important families that play key roles in auxin signal transduction. Both of the families contain a similar carboxyl-terminal domain (Domain III/IV that facilitates interactions between these two families. In spite of the importance of protein-protein interactions among these transcription factors, the mechanisms involved in these interactions are largely unknown. In this study, we isolated six intragenic suppressors of an auxin insensitive mutant, Osiaa23. Among these suppressors, Osiaa23-R5 successfully rescued all the defects of the mutant. Sequence analysis revealed that an amino acid substitution occurred in the Tryptophan (W residue in Domain IV of Osiaa23. Yeast two-hybrid experiments showed that the mutation in Domain IV prevents the protein-protein interactions between Osiaa23 and OsARFs. Phylogenetic analysis revealed that the W residue is conserved in both OsIAAs and OsARFs. Next, we performed site-specific amino acid substitutions within Domain IV of OsARFs, and the conserved W in Domain IV was exchanged by Serine (S. The mutated OsARF(WSs can be released from the inhibition of Osiaa23 and maintain the transcriptional activities. Expression of OsARF(WSs in Osiaa23 mutant rescued different defects of the mutant. Our results suggest a previously unknown importance of Domain IV in both families and provide an indirect way to investigate functions of OsARFs.

  15. Osmium tetroxide, 2,2’-bipyridine: Electroactive marker for probing accessibility of tryptophan residues in proteins

    Czech Academy of Sciences Publication Activity Database

    Fojta, Miroslav; Billová, Sabina; Havran, Luděk; Pivoňková, Hana; Černocká, Hana; Horáková Brázdilová, Petra; Paleček, Emil

    2008-01-01

    Roč. 80, č. 12 (2008), s. 4598-4605 ISSN 0003-2700 R&D Projects: GA MŠk(CZ) LC06035; GA AV ČR(CZ) IAA4004402; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN400310651 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : osmium tetroxide * chemical modification * tryptophan Subject RIV: BO - Biophysics Impact factor: 5.712, year: 2008

  16. Oxidation of free, peptide and protein tryptophan residues mediated by AAPH-derived free radicals: role of alkoxyl and peroxyl radicals

    DEFF Research Database (Denmark)

    Fuentes-Lemus, E.; Dorta, E.; Escobar, E.

    2016-01-01

    The oxidation of tryptophan (Trp) residues, mediated by peroxyl radicals (ROOc), follows a complex mechanism involving free radical intermediates, and short chain reactions. The reactivity of Trp towards ROOc should be strongly affected by its inclusion in peptides and proteins. To examine...... the latter, we investigated (by fluorescence) the kinetic of the consumption of free, peptide- and protein-Trp residues towards AAPH (2,20 -azobis(2-amidinopropane)dihydrochloride)-derived free radicals. Interestingly, the initial consumption rates (Ri ) were only slightly influenced by the inclusion of Trp...... concentrations (10–50 mM), the values of Ri were nearly constant; and at high Trp concentrations (50 mM to 1 mM), a slower increase of Ri than expected for chain reactions. Similar behavior was detected for all three systems (free Trp, and Trp in peptides and proteins). For the first time we are showing...

  17. Dynamic fluorescence spectroscopy on single tryptophan mutants of EIImtl in detergent micelles : Effects of substrate binding and phosphorylation on the fluorescence and anisotropy decay

    NARCIS (Netherlands)

    Swaving Dijkstra, Dolf; Broos, J.; Visser, Antonie J.W.G.; van Hoek, A.; Robillard, George

    1997-01-01

    The effects of substrate and substrate analogue binding and phosphorylation on the conformational dynamics of the mannitol permease of Escherichia coli were investigated, using time-resolved fluorescence spectroscopy on mutants containing five single tryptophans situated in the membrane-embedded C

  18. Steady-state fluorescence and phosphorescence spectroscopic studies of bacterial luciferase tryptophan mutants.

    Science.gov (United States)

    Li, Z; Meighen, E A

    1994-09-01

    Bacterial luciferase, which catalyzes the bioluminescence reaction in luminous bacteria, consists of two nonidentical polypeptides, α and β. Eight mutants of luciferase with each of the tryptophans replaced by tyrosine were generated by site-directed mutagenesis and purified to homogeneity. The steady-state tryptophan fluorescence and low-temperature phosphorescence spectroscopic properties of these mutants were characterized. In some instances, mutation of only a single tryptophan residue resulted in large spectral changes. The tryptophan residues conserved in both the α and the β subunits exhibited distinct fluorescence emission properties, suggesting that these tryptophans have different local enviroments. The low-temperature phosphorescence data suggest that the tryptophans conserved in bot the α and the β subunits are not located at the subunit interface and/or involved in subunit interactions. The differences in the spectral properties of the mutants have provided useful information on the local environment of the individual tryptophan residues as well as on the quaternary structure of the protein.

  19. Homogeneous competitive assay of ligand affinities based on quenching fluorescence of tyrosine/tryptophan residues in a protein via Főrster-resonance-energy-transfer

    Science.gov (United States)

    Xie, Yanling; Yang, Xiaolan; Pu, Jun; Zhao, Yunsheng; Zhang, Ying; Xie, Guoming; Zheng, Jun; Yuan, Huidong; Liao, Fei

    2010-11-01

    A new homogeneous competitive assay of ligand affinities was proposed based on quenching the fluorescence of tryptophan/tyrosine residues in a protein via Főrster-resonance-energy-transfer using a fluorescent reference ligand as the acceptor. Under excitation around 280 nm, the fluorescence of a protein or a bound acceptor was monitored upon competitive binding against a nonfluorescent candidate ligand. Chemometrics for deriving the binding ratio of the acceptor with either fluorescence signal was discussed; the dissociation constant ( Kd) of a nonfluorescent candidate ligand was calculated from its concentration to displace 50% binding of the acceptor. N-biotinyl-N'-(1-naphthyl)-ethylenediamine (BNEDA) and N-biotinyl-N'-dansyl-ethylenediamine (BDEDA) were used as the reference ligands and acceptors to streptavidin to test this new homogeneous competitive assay. Upon binding of an acceptor to streptavidin, there were the quench of streptavidin fluorescence at 340 nm and the characteristic fluorescence at 430 nm for BNEDA or at 525 nm for BDEDA. Kd of BNEDA and BDEDA was obtained via competitive binding against biotin. By quantifying BNEDA fluorescence, Kd of each tested nonfluorescent biotin derivative was consistent with that by quantifying streptavidin fluorescence using BNEDA or BDEDA as the acceptor. The overall coefficients of variation were about 10%. Therefore, this homogeneous competitive assay was effective and promising to high-throughput-screening.

  20. Bioavailability of tryptophan from a single oral dose of a trytophan-enriched peptide mixture in healthy men

    NARCIS (Netherlands)

    Brink, E.J.; Boelsma, E.; Steijns, J.; Hendriks, H.F.J.

    2004-01-01

    The aim of the study was to investigate the bioavailability of tryptophan (Trp) from a Trp-enriched peptide mixture in healthy men. A second objective was to investigate the effect of this Trp-enriched protein hydrolysate on potential parameters of serotonergic activity. serum serotonim melatonin

  1. Docking studies of antidepressants against single crystal structure of tryptophan 2, 3-dioxygenase using Molegro Virtual Docker software.

    Science.gov (United States)

    Dawood, Shazia; Zarina, Shamshad; Bano, Samina

    2014-09-01

    Tryptophan 2, 3-dioxygenase (TDO) a heme containing enzyme found in mammalian liver is responsible for tryptophan (Trp) catabolism. Trp is an essential amino acid that is degraded in to N-formylkynurenine by the action of TDO. The protein ligand interaction plays a significant role in structural based drug designing. The current study illustrates the binding of established antidepressants (ADs) against TDO enzyme using in-silico docking studies. For this purpose, Fluoxetine, Paroxetine, Sertraline, Fluvoxamine, Seproxetine, Citalopram, Moclobamide, Hyperforin and Amoxepine were selected. In-silico docking studies were carried out using Molegro Virtual Docker (MVD) software. Docking results show that all ADs fit well in the active site of TDO moreover Hyperforin and Paroxetine exhibited high docking scores of -152.484k cal/mol and -139.706k cal/mol, respectively. It is concluded that Hyperforin and Paroxetine are possible lead molecules because of their high docking scores as compared to other ADs examined. Therefore, these two ADs stand as potent inhibitors of TDO enzyme.

  2. L-Tryptophan

    Science.gov (United States)

    ... tryptophan by mouth doesn't help reduce facial pain. Improving athletic ability. Some research shows that taking L-tryptophan for 3 days before exercising can improve power during exercise. This improvement in power helps increase ...

  3. Dynamic Allostery Mediated by a Conserved Tryptophan in the Tec Family Kinases.

    Directory of Open Access Journals (Sweden)

    Nikita Chopra

    2016-03-01

    Full Text Available Bruton's tyrosine kinase (Btk is a Tec family non-receptor tyrosine kinase that plays a critical role in immune signaling and is associated with the immunological disorder X-linked agammaglobulinemia (XLA. Our previous findings showed that the Tec kinases are allosterically activated by the adjacent N-terminal linker. A single tryptophan residue in the N-terminal 17-residue linker mediates allosteric activation, and its mutation to alanine leads to the complete loss of activity. Guided by hydrogen/deuterium exchange mass spectrometry results, we have employed Molecular Dynamics simulations, Principal Component Analysis, Community Analysis and measures of node centrality to understand the details of how a single tryptophan mediates allostery in Btk. A specific tryptophan side chain rotamer promotes the functional dynamic allostery by inducing coordinated motions that spread across the kinase domain. Either a shift in the rotamer population, or a loss of the tryptophan side chain by mutation, drastically changes the coordinated motions and dynamically isolates catalytically important regions of the kinase domain. This work also identifies a new set of residues in the Btk kinase domain with high node centrality values indicating their importance in transmission of dynamics essential for kinase activation. Structurally, these node residues appear in both lobes of the kinase domain. In the N-lobe, high centrality residues wrap around the ATP binding pocket connecting previously described Catalytic-spine residues. In the C-lobe, two high centrality node residues connect the base of the R- and C-spines on the αF-helix. We suggest that the bridging residues that connect the catalytic and regulatory architecture within the kinase domain may be a crucial element in transmitting information about regulatory spine assembly to the catalytic machinery of the catalytic spine and active site.

  4. Oxidation of the tryptophan 32 residue of human superoxide dismutase 1 caused by its bicarbonate-dependent peroxidase activity triggers the non-amyloid aggregation of the enzyme.

    Science.gov (United States)

    Coelho, Fernando R; Iqbal, Asif; Linares, Edlaine; Silva, Daniel F; Lima, Filipe S; Cuccovia, Iolanda M; Augusto, Ohara

    2014-10-31

    The role of oxidative post-translational modifications of human superoxide dismutase 1 (hSOD1) in the amyotrophic lateral sclerosis (ALS) pathology is an attractive hypothesis to explore based on several lines of evidence. Among them, the remarkable stability of hSOD1(WT) and several of its ALS-associated mutants suggests that hSOD1 oxidation may precede its conversion to the unfolded and aggregated forms found in ALS patients. The bicarbonate-dependent peroxidase activity of hSOD1 causes oxidation of its own solvent-exposed Trp(32) residue. The resulting products are apparently different from those produced in the absence of bicarbonate and are most likely specific for simian SOD1s, which contain the Trp(32) residue. The aims of this work were to examine whether the bicarbonate-dependent peroxidase activity of hSOD1 (hSOD1(WT) and hSOD1(G93A) mutant) triggers aggregation of the enzyme and to comprehend the role of the Trp(32) residue in the process. The results showed that Trp(32) residues of both enzymes are oxidized to a similar extent to hSOD1-derived tryptophanyl radicals. These radicals decayed to hSOD1-N-formylkynurenine and hSOD1-kynurenine or to a hSOD1 covalent dimer cross-linked by a ditryptophan bond, causing hSOD1 unfolding, oligomerization, and non-amyloid aggregation. The latter process was inhibited by tempol, which recombines with the hSOD1-derived tryptophanyl radical, and did not occur in the absence of bicarbonate or with enzymes that lack the Trp(32) residue (bovine SOD1 and hSOD1(W32F) mutant). The results support a role for the oxidation products of the hSOD1-Trp(32) residue, particularly the covalent dimer, in triggering the non-amyloid aggregation of hSOD1. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. The preference of tryptophan for membrane interfaces: insights from N-methylation of tryptophans in gramicidin channels.

    Science.gov (United States)

    Sun, Haiyan; Greathouse, Denise V; Andersen, Olaf S; Koeppe, Roger E

    2008-08-08

    To better understand the structural and functional roles of tryptophan at the membrane/water interface in membrane proteins, we examined the structural and functional consequences of Trp --> 1-methyl-tryptophan substitutions in membrane-spanning gramicidin A channels. Gramicidin A channels are miniproteins that are anchored to the interface by four Trps near the C terminus of each subunit in a membrane-spanning dimer. We masked the hydrogen bonding ability of individual or multiple Trps by 1-methylation of the indole ring and examined the structural and functional changes using circular dichroism spectroscopy, size exclusion chromatography, solid state (2)H NMR spectroscopy, and single channel analysis. N-Methylation causes distinct changes in the subunit conformational preference, channel-forming propensity, single channel conductance and lifetime, and average indole ring orientations within the membrane-spanning channels. The extent of the local ring dynamic wobble does not increase, and may decrease slightly, when the indole NH is replaced by the non-hydrogen-bonding and more bulky and hydrophobic N-CH(3) group. The changes in conformational preference, which are associated with a shift in the distribution of the aromatic residues across the bilayer, are similar to those observed previously with Trp --> Phe substitutions. We conclude that indole N-H hydrogen bonding is of major importance for the folding of gramicidin channels. The changes in ion permeability, however, are quite different for Trp --> Phe and Trp --> 1-methyl-tryptophan substitutions, indicating that the indole dipole moment and perhaps also ring size and are important for ion permeation through these channels.

  6. Rotational spectrum of tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, M. Eugenia, E-mail: maria.sanz@kcl.ac.uk; Cabezas, Carlos, E-mail: ccabezas@qf.uva.es; Mata, Santiago, E-mail: santiago.mata@uva.es; Alonso, Josè L., E-mail: jlalonso@qf.uva.es [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, 47011 Valladolid (Spain)

    2014-05-28

    The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the {sup 14}N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O–H···N hydrogen bond in the side chain and a N–H···π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

  7. Analysis of residual stress state in sheet metal parts processed by single point incremental forming

    Science.gov (United States)

    Maaß, F.; Gies, S.; Dobecki, M.; Brömmelhoff, K.; Tekkaya, A. E.; Reimers, W.

    2018-05-01

    The mechanical properties of formed metal components are highly affected by the prevailing residual stress state. A selective induction of residual compressive stresses in the component, can improve the product properties such as the fatigue strength. By means of single point incremental forming (SPIF), the residual stress state can be influenced by adjusting the process parameters during the manufacturing process. To achieve a fundamental understanding of the residual stress formation caused by the SPIF process, a valid numerical process model is essential. Within the scope of this paper the significance of kinematic hardening effects on the determined residual stress state is presented based on numerical simulations. The effect of the unclamping step after the manufacturing process is also analyzed. An average deviation of the residual stress amplitudes in the clamped and unclamped condition of 18 % reveals, that the unclamping step needs to be considered to reach a high numerical prediction quality.

  8. L-Tryptophan depletion bioreactor, a possible cancer therapy

    Directory of Open Access Journals (Sweden)

    Rolf Bambauer

    2015-04-01

    Full Text Available The cancer therapeutic strategies knownto date are not adequate for all cancer patients. Most of them are followed by a high rate of side effects and complications. The L-tryptophan depletion bioreactor is described as a possible new method of cancer therapy. L-tryptophan is an essential amino acid which has been recognized as an important cancer nutrient and its removal can lead to destruction of the tumour. Normal human cells or tumor cells cannot synthesize L-tryptophan and therefore tumor resistance is unlikely to develop. L-tryptophan is also a constituent for different bio-molecules such as Serotonin, Melatonin, and is needed for other synthesis processes in the cell growth. L-tryptophan degrading enzymes with 3 iso-enzymes called tryptophan side chain oxydase (TSO I, II, III were isolated. The 3 iso-enzymes can be differentiated by tryptic digestion. They have different molecular weights with different effectivenesses. All the TSO enzymes have heme that can catalyze essentially similar reactions involving L-tryptophan as a substrate. The most effective TSO is the type TSO III. A column which contained TSO as a bioreactor was integrated in a plasmapheresis unit and tested it in different animals. In sheep and rabbits L-tryptophan depletion in plasma was shown at 95% and 100% rates respectively by a single pass through the bioreactor. The results in immune supprimized rats with tumors were impressive, too. In 20 different tumor cell lines there were different efficacies. Brest cancer and medulloblastoma showed the greatest efficacy of L-tryptophan degrading. The gene technology of TSO production from Pseudomonas is associated with formation of endotoxins. This disadvantage can be prevented by different washing procedures or by using fungal sources for the TSO production. TSO III is developed to treat cancer diseases successfully, and has low side effects. A combination of L-tryptophan depletion with all available cancer therapies is

  9. Effect of residual stress on the nanoindentation response of (100) copper single crystal

    International Nuclear Information System (INIS)

    Zhu, Li-na; Xu, Bin-shi; Wang, Hai-dou; Wang, Cheng-biao

    2012-01-01

    Experimental measurements were used to investigate the effect of residual stress on the nanoindentation of (100) copper single crystal. Equi-biaxial tensile and compressive stresses were applied to the copper single crystal using a special designed apparatus. It was found that residual stresses greatly affected peak load, curvature of the loading curve, elastically recovered depth, residual depth, indentation work, pile-up amount and contact area. The Suresh and Giannakopoulos and Lee and Kwon methods were used to calculate the residual stresses from load-depth data and morphology observation of nanoindents using atomic force microscopy. Comparison of the obtained results with stress values from strain gage showed that the residual stresses analyzed from the Suresh and Giannakopoulos model agreed well with the applied stresses. -- Highlights: ► Residual stresses greatly affected various nanoindentation parameters. ► The contact area can be accurately measured from AFM observation. ► The residual stresses analyzed from the S and G model agreed well with applied stresses.

  10. UV radiation-induced photochemical damage of tryptophan in peptides, proteins and ocular lenses

    International Nuclear Information System (INIS)

    Hibbard, L.B.

    1985-01-01

    These studies were undertaken to investigate the possible involvement of the amino acid tryptophan in the near-ultraviolet radiation-induced photochemical alteration of peptides and proteins and the role tryptophan photolysis plays in ocular lens damage. Sample irradiations were performed to determine if tryptophan photolysis occurs with radiation in the UV-A region in comparison to photolysis induced by wavelengths in the normal absorption band of the amino acid (UV-B). Photolysis studies were carried out on free tryptophan and two dipeptides, tryptophyglycine and glycyltryptophan, in aqueous solutions at different pH values in the range 4.5-10.0 under aerated or anaerobic conditions. Rates of photolysis of these 290 nm-irradiated compounds, detected by observing tryptophan fluorescence intensity loss during irradiation, were compared and significant differences were observed for each compound which varied with pH and oxygen environment. Another series of experiments examined the photolysis of tryptophan residues in lens proteins in whole rat lenses induced by 290 nm and 298 nm dye laser radiation. Tryptophan residue photolysis was, once again, monitored by loss in tryptophan fluorescence intensity. A relationship was derived between tryptophan loss and photoproduct buildup during irradiation

  11. Tryptophan and ATTO 590: mutual fluorescence quenching and exciplex formation.

    Science.gov (United States)

    Bhattacharjee, Ujjal; Beck, Christie; Winter, Arthur; Wells, Carson; Petrich, Jacob W

    2014-07-24

    Investigation of fluorescence quenching of probes, such as ATTO dyes, is becoming an increasingly important topic owing to the use of these dyes in super-resolution microscopies and in single-molecule studies. Photoinduced electron transfer is their most important nonradiative pathway. Because of the increasing frequency of the use of ATTO and related dyes to investigate biological systems, studies are presented for inter- and intramolecular quenching of ATTO 590 with tryptophan. In order to examine intramolecular quenching, an ATTO 590-tryptophan conjugate was synthesized. It was determined that tryptophan is efficiently quenching ATTO 590 fluorescence by excited-state charge transfer and two charge transfer complexes are forming. In addition, it was discovered that an exciplex (whose lifetime is 5.6 ns) can be formed between tryptophan and ATTO 590, and it is suggested that the possibility of such exciplex formation should be taken into account when protein fluorescence is monitored in a system tagged with ATTO dyes.

  12. TRYPTOPHAN PROMOTES CHARITABLE DONATING

    Directory of Open Access Journals (Sweden)

    Laura eSteenbergen

    2014-12-01

    Full Text Available The link between serotonin (5-HT and one of the most important elements of prosocial behavior, charity, has remained largely uninvestigated. In the present study, we tested whether charitable donating can be promoted by administering the food supplement L-Tryptophan (TRP, the biochemical precursor of 5-HT. Participants were compared with respect to the amount of money they donated when given the opportunity to make a charitable donation. As expected, compared to a neutral placebo, TRP appears to increase the participants’ willingness to donate money to a charity. This result supports the idea that the food we eat may act as a cognitive enhancer modulating the way we think and perceive the world and others.

  13. Residual Stress State in Single-Edge Notched Tension Specimen Caused by the Local Compression Technique

    Directory of Open Access Journals (Sweden)

    Huang Yifan

    2016-12-01

    Full Text Available Three-dimensional (3D finite element analyses (FEA are performed to simulate the local compression (LC technique on the clamped single-edge notched tension (SE(T specimens. The analysis includes three types of indenters, which are single pair of cylinder indenters (SPCI, double pairs of cylinder indenters (DPCI and single pair of ring indenters (SPRI. The distribution of the residual stress in the crack opening direction in the uncracked ligament of the specimen is evaluated. The outcome of this study can facilitate the use of LC technique on SE(T specimens.

  14. Contaminant Release from Residual Waste in Single Shell Tanks at the Hanford Site, Washington, USA - 9276

    International Nuclear Information System (INIS)

    Cantrell, Kirk J.; Krupka, Kenneth M.; Deutsch, William J.; Lindberg, Michael J.

    2009-01-01

    Determinations of elemental and solid-phase compositions, and contaminant release studies have been applied in an ongoing study of residual tank wastes (i.e., waste remaining after final retrieval operations) from five of 149 underground single-shell storage tanks (241-C-103, 241-C-106, 241-C-202, 241-C-203, and 241-S-112) at the U.S. Department of Energy's Hanford Site in Washington State. This work is being conducted to support performance assessments that will be required to evaluate long-term health and safety risks associated with tank site closure. The results of studies completed to date show significant variability in the compositions, solid phase properties, and contaminant release characteristics from these residual tank wastes. This variability is the result of differences in waste chemistry/composition of wastes produced from several different spent fuel reprocessing schemes, subsequent waste reprocessing to remove certain target constituents, tank farm operations that concentrated wastes and mixed wastes between tanks, and differences in retrieval processes used to remove the wastes from the tanks. Release models were developed based upon results of chemical characterization of the bulk residual waste, solid-phase characterization (see companion paper 9277 by Krupka et al.), leaching and extraction experiments, and geochemical modeling. In most cases empirical release models were required to describe contaminant release from these wastes. Release of contaminants from residual waste was frequently found to be controlled by the solubility of phases that could not be identified and/or for which thermodynamic data and/or dissolution rates have not been measured. For example, significant fractions of Tc-99, I-129, and Cr appear to be coprecipitated at trace concentrations in metal oxide phases that could not be identified unambiguously. In the case of U release from tank 241-C-103 residual waste, geochemical calculations indicated that leachate

  15. Investigations of Residual Stresses and Mechanical Properties of Single Crystal Niobium for SRF Cavities

    Science.gov (United States)

    Gnäupel-Herold, Thomas; Myneni, Ganapati Rao; Ricker, Richard E.

    2007-08-01

    This work investigates properties of large grained, high purity niobium with respect to the forming of superconducting radio frequency (SRF) cavities from such large grained sheets. The yield stresses were examined using tensile specimens that were essentially single crystals in orientations evenly distributed in the standard projection triangle. No distinct yield anisotropy was found, however, vacuum annealing increased the yield strength by a factor 2…3. The deep drawing forming operation of the half cells raises the issues of elastic shape changes after the release of the forming tool (springback) and residual stresses, both of which are indicated to be negligible. This is a consequence of the low yield stress (sheet metal forming). However, the significant anisotropy of the transversal plastic strains after uniaxial deformation points to potentially critical thickness variations for large grained / single crystal half cells, thus raising the issue of controlling grain orientation or using single crystal sheet material.

  16. Tryptophan Research in Panic Disorder

    Directory of Open Access Journals (Sweden)

    Eduard Maron

    2008-01-01

    Full Text Available A considerable body of evidence suggests the involvement of serotonin neurotransmission in the pathogenesis of panic disorder. Research on pathways and functions of tryptophan, an essential amino acid converted into serotonin, may advance our understanding of serotonergic actions in panic disorder and related phenomena. The investigative approaches in this field include manipulations of tryptophan availability as well as genetic association and functional brain imaging studies. In this review we examine the principle findings of these studies and propose further research directions.

  17. Enhancement of stability of L-tryptophan dehydrogenase from Nostoc punctiforme ATCC29133 and its application to L-tryptophan assay.

    Science.gov (United States)

    Matsui, Daisuke; Okazaki, Seiji; Matsuda, Motoki; Asano, Yasuhisa

    2015-02-20

    Microbial NAD(+)-dependent L-tryptophan dehydrogenase (TrpDH, EC1.4.1.19), which catalyzes the reversible oxidative deamination and the reductive amination between L-tryptophan and indole-3-pyruvic acid, was found in the scytonemin biosynthetic pathway of Nostoc punctiforme ATCC29133. The TrpDH exhibited high specificity toward L-tryptophan, but its instability was a drawback for L-tryptophan determination. The mutant enzyme TrpDH L59F/D168G/A234D/I296N with thermal stability was obtained by screening of Escherichia coli transformants harboring various mutant genes, which were generated by error-prone PCR using complementation in an L-tryptophan auxotroph of E. coli. The specific activity and stability of this mutant enzyme were higher than those of the wild type enzyme. We also revealed here that in these four mutation points, the two amino acid residues Asp168 and Ile296 contributed to increase the enzyme stability, and the Leu59, Ala234 residues to increase its specific activity. Growth of the strain harboring the gene of above 4 point mutated enzyme was accelerated by the enhanced performance. In the present study, we demonstrated that TrpDH L59F/D168G/A234D/I296N was available for determination of L-tryptophan in human plasma. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Residual strain evolution during the deformation of single fiber metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Hanan, J.C.; Uestuendag, E.; Clausen, B. [Dept. of Materials Science, California Inst. of Tech., Pasadena, CA (United States); Sivasambu, M.; Beyerlein, I.J. [Theoretical Div., Los Alamos National Lab., Los Alamos, NM (United States); Brown, D.W.; Bourke, M.A.M. [Materials Science and Technology Div., Los Alamos National Lab., Los Alamos, NM (United States)

    2002-07-01

    Successful application of metal matrix composites often requires strength and lifetime predictions that account for the deformation of each phase. Yet, the deformation of individual phases in composites usually differs significantly from their respective monolithic behaviors. An approach is presented that quantifies the deformation parameters of each phase using neutron diffraction measurements before, during, and after failure under tensile loading in model composites consisting of a single alumina fiber embedded in an aluminum matrix. The evolution of residual strains after loading was examined including the effects of fiber failure. (orig.)

  19. Ab initio study on electron excitation and electron transfer in tryptophan-tyrosine system

    International Nuclear Information System (INIS)

    Tong Jing; Li Xiangyuan

    2002-01-01

    In this article, ab initio calculation has been performed to evaluate the transition energy of electronic excitation in tryptophan and tyrosine by using semiempirical molecular orbital method AM1 and complete active space self-consistent field method. The solvent effect has been considered by means of the conductor-like screening model. After geometric optimizations of isolated tryptophan and tyrosine, and their corresponding radicals and cations, reaction heat of these electron transfer reactions have been obtained by the means of complete active space self-consistent field method. The transition energies from the ground state, respectively, to the lowest excited state and to the lowest triplet state of these two amino acids are also calculated and compared with the experimentally observed values. The ionization potential and electron affinity are also calculated for tryptophan and tyrosine employing Koopmans' theorem and ab initio calculation. Compared with the experimental measurements, the theoretical results are found satisfactory. Theoretical results give good explanations on the experimental phenomena that N 3 · can preferably oxide the side chain of tryptophan residue and then the electron transfer from tyrosine residue to tryptophan residue follows in peptides involving tryptophan and tyrosine

  20. Analysis of cosmetic residues on a single human hair by ATR FT-IR microspectroscopy

    Science.gov (United States)

    Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Naranitad, Suwimol; Ekgasit, Sanong

    2018-05-01

    In this work, ATR FT-IR spectra of single human hair and cosmetic residues on hair surface are successfully collected using a homemade dome-shaped Ge μIRE accessary installed on an infrared microscope. By collecting ATR spectra of hairs from the same person, the spectral patterns are identical and superimposed while different spectral features are observed from ATR spectra of hairs collected from different persons. The spectral differences depend on individual hair characteristics, chemical treatments, and cosmetics on hair surface. The "Contact-and-Collect" technique that transfers remarkable materials on the hair surface to the tip of the Ge μIRE enables an identification of cosmetics on a single hair. Moreover, the differences between un-split and split hairs are also studied in this report. These highly specific spectral features can be employed for unique identification or for differentiation of hairs based on the molecular structures of hairs and cosmetics on hairs.

  1. Effects of residual aberrations explored on single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Biskupek, Johannes; Hartel, Peter; Haider, Maximilian; Kaiser, Ute

    2012-01-01

    The effects of geometric residual aberrations such as coma B 2 and two-fold astigmatism A 1 on the contrast in aberration corrected high resolution transmission electron microscopy (HRTEM) images are investigated on single-walled carbon nanotubes (SWNT). The individual aberrations are adjusted and set up manually using an imaging C S -corrector. We demonstrate how coma B 2 can be recognized by an experienced user directly in the image and how it blurs the contrast. Even with uncorrected (resolution limiting) spherical aberration C S the coma B 2 has to be considered and must be minimized. Limits for a tolerable coma are given. The experiments are confirmed by image simulations. -- Highlights: ► Individual effects of residual aberrations such as B 2 , A 1 , and C S are demonstrated. ► Experimental HRTEM and simulated images of carbon nanotubes are compared. ► A detection limit of 50 nm B 2 in a single HRTEM image is determined.

  2. Twenty-four-hour plasma tryptophan concentrations and ratios are below normal in obese subjects and are not normalized by substantial weight reduction

    DEFF Research Database (Denmark)

    Breum, Leif; Rasmussen, Michael H; Hilsted, Jannik

    2003-01-01

    BACKGROUND: Plasma tryptophan concentrations and the ratio of tryptophan to other large neutral amino acids (plasma tryptophan ratio) are reportedly low in obese subjects. The plasma tryptophan ratio predicts brain tryptophan uptake and serotonin production. If this ratio is low in obese subjects......, serotonin function may also be low. Plasma tryptophan concentrations and ratios have been measured only at single time points in obese subjects; it is not known whether low values for these 2 variables persist throughout a 24-h period. OBJECTIVE: Our objective was to determine whether plasma tryptophan...... concentrations and ratios in obese subjects are lower than those in normal-weight subjects throughout a 24-h period and whether they increase when body weight is reduced. DESIGN: Plasma tryptophan concentrations and ratios were examined in obese subjects before and after weight loss and in nonobese control...

  3. Single-well experimental design for studying residual trapping of superciritcal carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Freifeld, B.; Finsterle, S.; Leahy, M.; Ennis-King, J.; Paterson, L.; Dance, T.

    2010-06-15

    The objective of our research is to design a single-well injection-withdrawal test to evaluate residual phase trapping at potential CO{sub 2} geological storage sites. Given the significant depths targeted for CO{sub 2} storage and the resulting high costs associated with drilling to those depths, it is attractive to develop a single-well test that can provide data to assess reservoir properties and reduce uncertainties in the appraisal phase of site investigation. The main challenges in a single-well test design include (1) difficulty in quantifying the amount of CO{sub 2} that has dissolved into brine or migrated away from the borehole; (2) non-uniqueness and uncertainty in the estimate of the residual gas saturation (S{sub gr}) due to correlations among various parameters; and (3) the potential biased S{sub gr} estimate due to unaccounted heterogeneity of the geological medium. To address each of these challenges, we propose (1) to use a physical-based model to simulation test sequence and inverse modeling to analyze data information content and to quantify uncertainty; (2) to jointly use multiple data types generated from different kinds of tests to constrain the Sgr estimate; and (3) to reduce the sensitivity of the designed tests to geological heterogeneity by conducting the same test sequence in both a water-saturated system and a system with residual gas saturation. To perform the design calculation, we build a synthetic model and conduct a formal analysis for sensitivity and uncertain quantification. Both parametric uncertainty and geological uncertainty are considered in the analysis. Results show (1) uncertainty in the estimation of Sgr can be reduced by jointly using multiple data types and repeated tests; and (2) geological uncertainty is essential and needs to be accounted for in the estimation of S{sub gr} and its uncertainty. The proposed methodology is applied to the design of a CO{sub 2} injection test at CO2CRC's Otway Project Site, Victoria

  4. Investigations of Residual Stresses and Mechanical Properties of Single Crystal Niobium for SRF Cavities

    International Nuclear Information System (INIS)

    Gnaeupel-Herold, Thomas; Myneni, Ganapati Rao; Ricker, Richard E.

    2007-01-01

    This work investigates properties of large grained, high purity niobium with respect to the forming of superconducting radio frequency (SRF) cavities from such large grained sheets. The yield stresses were examined using tensile specimens that were essentially single crystals in orientations evenly distributed in the standard projection triangle. No distinct yield anisotropy was found, however, vacuum annealing increased the yield strength by a factor 2...3. The deep drawing forming operation of the half cells raises the issues of elastic shape changes after the release of the forming tool (springback) and residual stresses, both of which are indicated to be negligible. This is a consequence of the low yield stress (< 100 MPa) and the large thickness (compared to typical thicknesses in sheet metal forming). However, the significant anisotropy of the transversal plastic strains after uniaxial deformation points to potentially critical thickness variations for large grained / single crystal half cells, thus raising the issue of controlling grain orientation or using single crystal sheet material

  5. Residual toxicity in hematopoietic cells following a single dose of methylnitrosourea

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, T.; Cronkite, E.P.; Commerford, S.L.; Carsten, A.L.

    1984-01-01

    The residual injury to the proliferation capability of hemopoietic stem cells (CFU-S) which results from their exposure to leukemogenic agents was evaluated in mice given a single leukemogenic dose of methol nitrosourea. Bone marrow cellularity, splenic weight, number of CFU-S and the proportion of cycling to noncycling CFU-S were measured in an effort to detect acute and residual injury to the CFU-S from mice given MNU 21 and 3 days earlier. Marrow cells were also transferred into lethally irradiated mice to observe the self-renewal capability of the CFU-S in the recipient spleen and bone marrow. The results of these measurements show that the CFU-S in marrow from mice given 50 mg/kg of MNU 21 days earlier still have a defective ability for self-renewal, although the total cellularity, number of CFU-S and proportion of cycling and noncycling CFU-S in the donor have returned to the normal range. The relationship of this self-renewal defect to the development of leukemia after this leukemogenic dose of MNU is not known. 21 references, 9 figures, 3 tables.

  6. Analysis of cosmetic residues on a single human hair by ATR FT-IR microspectroscopy.

    Science.gov (United States)

    Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Naranitad, Suwimol; Ekgasit, Sanong

    2018-05-15

    In this work, ATR FT-IR spectra of single human hair and cosmetic residues on hair surface are successfully collected using a homemade dome-shaped Ge μIRE accessary installed on an infrared microscope. By collecting ATR spectra of hairs from the same person, the spectral patterns are identical and superimposed while different spectral features are observed from ATR spectra of hairs collected from different persons. The spectral differences depend on individual hair characteristics, chemical treatments, and cosmetics on hair surface. The "Contact-and-Collect" technique that transfers remarkable materials on the hair surface to the tip of the Ge μIRE enables an identification of cosmetics on a single hair. Moreover, the differences between un-split and split hairs are also studied in this report. These highly specific spectral features can be employed for unique identification or for differentiation of hairs based on the molecular structures of hairs and cosmetics on hairs. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Functional diversity of Csk, Chk, and Src SH2 domains due to a single residue variation.

    Science.gov (United States)

    Ayrapetov, Marina K; Nam, Nguyen Hai; Ye, Guofeng; Kumar, Anil; Parang, Keykavous; Sun, Gongqin

    2005-07-08

    The C-terminal Src kinase (Csk) family of protein tyrosine kinases contains two members: Csk and Csk homologous kinase (Chk). Both phosphorylate and inactivate Src family kinases. Recent reports suggest that the Src homology (SH) 2 domains of Csk and Chk may bind to different phosphoproteins, which provides a basis for different cellular functions for Csk and Chk. To verify and characterize such a functional divergence, we compared the binding properties of the Csk, Chk, and Src SH2 domains and investigated the structural basis for the functional divergence. First, the study demonstrated striking functional differences between the Csk and Chk SH2 domains and revealed functional similarities between the Chk and Src SH2 domains. Second, structural analysis and mutagenic studies revealed that the functional differences among the three SH2 domains were largely controlled by one residue, Glu127 in Csk, Ile167 in Chk, and Lys200 in Src. Mutating these residues in the Csk or Chk SH2 domain to the Src counterpart resulted in dramatic gain of function similar to Src SH2 domain, whereas mutating Lys200 in Src SH2 domain to Glu (the Csk counterpart) resulted in loss of Src SH2 function. Third, a single point mutation of E127K rendered Csk responsive to activation by a Src SH2 domain ligand. Finally, the optimal phosphopeptide sequence for the Chk SH2 domain was determined. These results provide a compelling explanation for the functional differences between two homologous protein tyrosine kinases and reveal a new structure-function relationship for the SH2 domains.

  8. A single amino acid residue controls Ca2+ signaling by an octopamine receptor from Drosophila melanogaster.

    Science.gov (United States)

    Hoff, Max; Balfanz, Sabine; Ehling, Petra; Gensch, Thomas; Baumann, Arnd

    2011-07-01

    Rhythmic activity of cells and cellular networks plays an important role in physiology. In the nervous system oscillations of electrical activity and/or second messenger concentrations are important to synchronize neuronal activity. At the molecular level, rhythmic activity can be initiated by different routes. We have recently shown that an octopamine-activated G-protein-coupled receptor (GPCR; DmOctα1Rb, CG3856) from Drosophila initiates Ca(2+) oscillations. Here, we have unraveled the molecular basis of cellular Ca(2+) signaling controlled by the DmOctα1Rb receptor using a combination of pharmacological intervention, site-directed mutagenesis, and functional cellular Ca(2+) imaging on heterologously expressed receptors. Phosphorylation of a single amino acid residue in the third intracellular loop of the GPCR by PKC is necessary and sufficient to desensitize the receptor. From its desensitized state, DmOctα1Rb is resensitized by dephosphorylation, and a new Ca(2+) signal occurs on octopamine stimulation. Our findings show that transient changes of the receptor's surface profile have a strong effect on its physiological signaling properties. We expect that the detailed knowledge of DmOctα1Rb-dependent signal transduction fosters the identification of specific drugs that can be used for GPCR-mediated pest control, since octopamine serves important physiological and behavioral functions in arthropods.

  9. Regulatory Closure Options for the Residue in the Hanford Site Single-Shell Tanks

    International Nuclear Information System (INIS)

    Cochran, J.R.; Shyr, L.J.

    1998-01-01

    Liquid, mixed, high-level radioactive waste (HLW) has been stored in 149 single-shell tanks (SSTS) located in tank farms on the U.S. Department of Energy's (DOE's) Hanford Site. The DOE is developing technologies to retrieve as much remaining HLW as technically possible prior to physically closing the tank farms. In support of the Hanford Tanks Initiative, Sandia National Laboratories has addressed the requirements for the regulatory closure of the radioactive component of any SST residue that may remain after physical closure. There is significant uncertainty about the end state of each of the 149 SSTS; that is, the nature and amount of wastes remaining in the SSTS after retrieval is uncertain. As a means of proceeding in the face of these uncertainties, this report links possible end-states with associated closure options. Requirements for disposal of HLW and low-level radioactive waste (LLW) are reviewed in detail. Incidental waste, which is radioactive waste produced incidental to the further processing of HLW, is then discussed. If the low activity waste (LAW) fraction from the further processing of HLW is determined to be incidental waste, then DOE can dispose of that incidental waste onsite without a license from the U.S. Nuclear Regulatory Commissions (NRC). The NRC has proposed three Incidental Waste Criteria for determining if a LAW fraction is incidental waste. One of the three Criteria is that the LAW fraction should not exceed the NRC's Class C limits

  10. Regulatory Closure Options for the Residue in the Hanford Site Single-Shell Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, J.R. Shyr, L.J.

    1998-10-05

    Liquid, mixed, high-level radioactive waste (HLW) has been stored in 149 single-shell tanks (SSTS) located in tank farms on the U.S. Department of Energy's (DOE's) Hanford Site. The DOE is developing technologies to retrieve as much remaining HLW as technically possible prior to physically closing the tank farms. In support of the Hanford Tanks Initiative, Sandia National Laboratories has addressed the requirements for the regulatory closure of the radioactive component of any SST residue that may remain after physical closure. There is significant uncertainty about the end state of each of the 149 SSTS; that is, the nature and amount of wastes remaining in the SSTS after retrieval is uncertain. As a means of proceeding in the face of these uncertainties, this report links possible end-states with associated closure options. Requirements for disposal of HLW and low-level radioactive waste (LLW) are reviewed in detail. Incidental waste, which is radioactive waste produced incidental to the further processing of HLW, is then discussed. If the low activity waste (LAW) fraction from the further processing of HLW is determined to be incidental waste, then DOE can dispose of that incidental waste onsite without a license from the U.S. Nuclear Regulatory Commissions (NRC). The NRC has proposed three Incidental Waste Criteria for determining if a LAW fraction is incidental waste. One of the three Criteria is that the LAW fraction should not exceed the NRC's Class C limits.

  11. Ultrafast quenching of tryptophan fluorescence in proteins: Interresidue and intrahelical electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Weihong; Li Tanping; Zhang Luyuan; Yang Yi; Kao Yating; Wang Lijuan [Department of Physics, Chemistry, and Biochemistry, Program of Biophysics, Chemical Physics, and Biochemistry, Ohio State University, Columbus, OH 43210 (United States); Zhong Dongping [Department of Physics, Chemistry, and Biochemistry, Program of Biophysics, Chemical Physics, and Biochemistry, Ohio State University, Columbus, OH 43210 (United States)], E-mail: dongping@mps.ohio-state.edu

    2008-06-23

    Quenching of tryptophan fluorescence in proteins has been critical to the understanding of protein dynamics and enzyme reactions using tryptophan as a molecular optical probe. We report here our systematic examinations of potential quenching residues with more than 40 proteins. With site-directed mutation, we placed tryptophan to desired positions or altered its neighboring residues to screen quenching groups among 20 amino acid residues and of peptide backbones. With femtosecond resolution, we observed the ultrafast quenching dynamics within 100 ps and identified two ultrafast quenching groups, the carbonyl- and sulfur-containing residues. The former is glutamine and glutamate residues and the later is disulfide bond and cysteine residue. The quenching by the peptide-bond carbonyl group as well as other potential residues mostly occurs in longer than 100 ps. These ultrafast quenching dynamics occur at van der Waals distances through intraprotein electron transfer with high directionality. Following optimal molecular orbital overlap, electron jumps from the benzene ring of the indole moiety in a vertical orientation to the LUMO of acceptor quenching residues. Molecular dynamics simulations were invoked to elucidate various correlations of quenching dynamics with separation distances, relative orientations, local fluctuations and reaction heterogeneity. These unique ultrafast quenching pairs, as recently found to extensively occur in high-resolution protein structures, may have significant biological implications.

  12. Oxidative Modification of Tryptophan-Containing Peptides

    DEFF Research Database (Denmark)

    Petersen, Jonas; Christensen, Pia Katrine; Nielsen, Mathias T

    2018-01-01

    We herein present a broadly useful method for the chemoselective modification of a wide range of tryptophan-containing peptides. Exposing a tryptophan-containing peptide to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in a selective cyclodehydration between the peptide backbone...

  13. Effects of Tryptophan Content and Backbone Spacing on the Uptake Efficiency of Cell-Penetrating Peptides

    KAUST Repository

    Rydberg, Hanna A.; Matson, Maria; Å mand, Helene L.; Esbjö rner, Elin K.; Nordé n, Bengt

    2012-01-01

    Cell-penetrating peptides (CPPs) are able to traverse cellular membranes and deliver macromolecular cargo. Uptake occurs through both endocytotic and nonendocytotic pathways, but the molecular requirements for efficient internalization are not fully understood. Here we investigate how the presence of tryptophans and their position within an oligoarginine influence uptake mechanism and efficiency. Flow cytometry and confocal fluorescence imaging are used to estimate uptake efficiency, intracellular distribution and toxicity in Chinese hamster ovarian cells. Further, membrane leakage and lipid membrane affinity are investigated. The peptides contain eight arginine residues and one to four tryptophans, the tryptophans positioned either at the N-terminus, in the middle, or evenly distributed along the amino acid sequence. Our data show that the intracellular distribution varies among peptides with different tryptophan content and backbone spacing. Uptake efficiency is higher for the peptides with four tryptophans in the middle, or evenly distributed along the peptide sequence, than for the peptide with four tryptophans at the N-terminus. All peptides display low cytotoxicity except for the one with four tryptophans at the N-terminus, which was moderately toxic. This finding is consistent with their inability to induce efficient leakage of dye from lipid vesicles. All peptides have comparable affinities for lipid vesicles, showing that lipid binding is not a decisive parameter for uptake. Our results indicate that tryptophan content and backbone spacing can affect both the CPP uptake efficiency and the CPP uptake mechanism. The low cytotoxicity of these peptides and the possibilities of tuning their uptake mechanism are interesting from a therapeutic point of view. © 2012 American Chemical Society.

  14. Effects of Tryptophan Content and Backbone Spacing on the Uptake Efficiency of Cell-Penetrating Peptides

    KAUST Repository

    Rydberg, Hanna A.

    2012-07-10

    Cell-penetrating peptides (CPPs) are able to traverse cellular membranes and deliver macromolecular cargo. Uptake occurs through both endocytotic and nonendocytotic pathways, but the molecular requirements for efficient internalization are not fully understood. Here we investigate how the presence of tryptophans and their position within an oligoarginine influence uptake mechanism and efficiency. Flow cytometry and confocal fluorescence imaging are used to estimate uptake efficiency, intracellular distribution and toxicity in Chinese hamster ovarian cells. Further, membrane leakage and lipid membrane affinity are investigated. The peptides contain eight arginine residues and one to four tryptophans, the tryptophans positioned either at the N-terminus, in the middle, or evenly distributed along the amino acid sequence. Our data show that the intracellular distribution varies among peptides with different tryptophan content and backbone spacing. Uptake efficiency is higher for the peptides with four tryptophans in the middle, or evenly distributed along the peptide sequence, than for the peptide with four tryptophans at the N-terminus. All peptides display low cytotoxicity except for the one with four tryptophans at the N-terminus, which was moderately toxic. This finding is consistent with their inability to induce efficient leakage of dye from lipid vesicles. All peptides have comparable affinities for lipid vesicles, showing that lipid binding is not a decisive parameter for uptake. Our results indicate that tryptophan content and backbone spacing can affect both the CPP uptake efficiency and the CPP uptake mechanism. The low cytotoxicity of these peptides and the possibilities of tuning their uptake mechanism are interesting from a therapeutic point of view. © 2012 American Chemical Society.

  15. Effect of increased exposure times on amount of residual monomer released from single-step self-etch adhesives.

    Science.gov (United States)

    Altunsoy, Mustafa; Botsali, Murat Selim; Tosun, Gonca; Yasar, Ahmet

    2015-10-16

    The aim of this study was to evaluate the effect of increased exposure times on the amount of residual Bis-GMA, TEGDMA, HEMA and UDMA released from single-step self-etch adhesive systems. Two adhesive systems were used. The adhesives were applied to bovine dentin surface according to the manufacturer's instructions and were polymerized using an LED curing unit for 10, 20 and 40 seconds (n = 5). After polymerization, the specimens were stored in 75% ethanol-water solution (6 mL). Residual monomers (Bis-GMA, TEGDMA, UDMA and HEMA) that were eluted from the adhesives (after 10 minutes, 1 hour, 1 day, 7 days and 30 days) were analyzed by high-performance liquid chromatography (HPLC). The data were analyzed using 1-way analysis of variance and Tukey HSD tests. Among the time periods, the highest amount of released residual monomers from adhesives was observed in the 10th minute. There were statistically significant differences regarding released Bis-GMA, UDMA, HEMA and TEGDMA between the adhesive systems (p<0.05). There were no significant differences among the 10, 20 and 40 second polymerization times according to their effect on residual monomer release from adhesives (p>0.05). Increasing the polymerization time did not have an effect on residual monomer release from single-step self-etch adhesives.

  16. Serum Stabilities of Short Tryptophan-and Arginine-Rich Antimicrobial Peptide Analogs

    NARCIS (Netherlands)

    Nguyen, L.T.; Chau, J.K.; Perry, N.A.; de Boer, L.; Zaat, S.A.J.; Vogel, H.J.

    2010-01-01

    Background: Several short antimicrobial peptides that are rich in tryptophan and arginine residues were designed with a series of simple modifications such as end capping and cyclization. The two sets of hexapeptides are based on the Trp- and Arg-rich primary sequences from the "antimicrobial

  17. The mining of toxin-like polypeptides from EST database by single residue distribution analysis.

    Science.gov (United States)

    Kozlov, Sergey; Grishin, Eugene

    2011-01-31

    Novel high throughput sequencing technologies require permanent development of bioinformatics data processing methods. Among them, rapid and reliable identification of encoded proteins plays a pivotal role. To search for particular protein families, the amino acid sequence motifs suitable for selective screening of nucleotide sequence databases may be used. In this work, we suggest a novel method for simplified representation of protein amino acid sequences named Single Residue Distribution Analysis, which is applicable both for homology search and database screening. Using the procedure developed, a search for amino acid sequence motifs in sea anemone polypeptides was performed, and 14 different motifs with broad and low specificity were discriminated. The adequacy of motifs for mining toxin-like sequences was confirmed by their ability to identify 100% toxin-like anemone polypeptides in the reference polypeptide database. The employment of novel motifs for the search of polypeptide toxins in Anemonia viridis EST dataset allowed us to identify 89 putative toxin precursors. The translated and modified ESTs were scanned using a special algorithm. In addition to direct comparison with the motifs developed, the putative signal peptides were predicted and homology with known structures was examined. The suggested method may be used to retrieve structures of interest from the EST databases using simple amino acid sequence motifs as templates. The efficiency of the procedure for directed search of polypeptides is higher than that of most currently used methods. Analysis of 39939 ESTs of sea anemone Anemonia viridis resulted in identification of five protein precursors of earlier described toxins, discovery of 43 novel polypeptide toxins, and prediction of 39 putative polypeptide toxin sequences. In addition, two precursors of novel peptides presumably displaying neuronal function were disclosed.

  18. The mining of toxin-like polypeptides from EST database by single residue distribution analysis

    Directory of Open Access Journals (Sweden)

    Grishin Eugene

    2011-01-01

    Full Text Available Abstract Background Novel high throughput sequencing technologies require permanent development of bioinformatics data processing methods. Among them, rapid and reliable identification of encoded proteins plays a pivotal role. To search for particular protein families, the amino acid sequence motifs suitable for selective screening of nucleotide sequence databases may be used. In this work, we suggest a novel method for simplified representation of protein amino acid sequences named Single Residue Distribution Analysis, which is applicable both for homology search and database screening. Results Using the procedure developed, a search for amino acid sequence motifs in sea anemone polypeptides was performed, and 14 different motifs with broad and low specificity were discriminated. The adequacy of motifs for mining toxin-like sequences was confirmed by their ability to identify 100% toxin-like anemone polypeptides in the reference polypeptide database. The employment of novel motifs for the search of polypeptide toxins in Anemonia viridis EST dataset allowed us to identify 89 putative toxin precursors. The translated and modified ESTs were scanned using a special algorithm. In addition to direct comparison with the motifs developed, the putative signal peptides were predicted and homology with known structures was examined. Conclusions The suggested method may be used to retrieve structures of interest from the EST databases using simple amino acid sequence motifs as templates. The efficiency of the procedure for directed search of polypeptides is higher than that of most currently used methods. Analysis of 39939 ESTs of sea anemone Anemonia viridis resulted in identification of five protein precursors of earlier described toxins, discovery of 43 novel polypeptide toxins, and prediction of 39 putative polypeptide toxin sequences. In addition, two precursors of novel peptides presumably displaying neuronal function were disclosed.

  19. Inhibition of tryptophan - pyrrolase activity and elevation of brain tryptophan concentration by fluoxetine in rats

    International Nuclear Information System (INIS)

    Bano, S.; Sherkheli, M.A

    2003-01-01

    Objective: To investigate in-vitro as well as in-vivo effects of various doses of fluoxetine (SSRI) on tryptophan metabolism in rates. Results: In in-vitro (10 - 1000 mM) as well in-vivo (0.5 - 30 mg/kg body wt.) studies, fluoxetine showed a statistically significant inhibition of rat liver tryptophan pyrrolase (tryptophan-2,3-dioxygenase; EC 1.13.11.11) activity. Significant increases were noted at 10 and 30 mg/kg doses in brain, serum (total and free) and liver L-tryptophan concentrations. Similarly, serum non-esterified free fatty acids showed a significant increase at both doses. There was no effect on serum glucose and albumin concentrations. Conclusion: It is suggested that major mechanism of action of fluoxetine is that of elevating brain tryptophan concentration and hence 5-HT synthesis by increasing the availability of circulating tryptophan to the brain secondarily to inhibition of major tryptophan degrading enzyme, hepatic tryptophan pyrrolase. It is assumed that fluoxetine inhibits the binding of apoenzyme form of tryptophan pyrrolase with its cofactor haem. The results are discussed in relation to possible involvement of disturbed hepatic tryptophan metabolism in depressive illness. (author)

  20. Correlation Between the Microstructural Defects and Residual Stress in a Single Crystal Nickel-Based Superalloy During Different Creep Stages

    Science.gov (United States)

    Mo, Fangjie; Wu, Erdong; Zhang, Changsheng; Wang, Hong; Zhong, Zhengye; Zhang, Jian; Chen, Bo; Hofmann, Michael; Gan, Weimin; Sun, Guangai

    2018-03-01

    The present work attempts to reveal the correlation between the microstructural defects and residual stress in the single crystal nickel-based superalloy, both of which play the significant role on properties and performance. Neutron diffraction was employed to investigate the microstructural defects and residual stresses in a single crystal (SC) nickel-based superalloy, which was subjected to creeping under 220 MPa and 1000 °C for different times. The measured superlattice and fundamental lattice reflections confirm that the mismatch and tetragonal distortions with c/a > 1 exist in the SC superalloy. At the initially unstrained state, there exists the angular distortion between γ and γ' phases with small triaxial compressive stresses, ensuring the structural stability of the superalloy. After creeping, the tetragonal distortion for the γ phase is larger than that for the γ' phase. With increasing the creeping time, the mismatch between γ and γ' phases increases to the maximum, then decreases gradually and finally remains unchanged. The macroscopic residual stress shows a similar behavior with the mismatch, indicating the correlation between them. Based on the model of shear and dislocations, the evolution of microstructural defects and residual stress are reasonably explained. The effect of shear is dominant at the primary creep stage, which greatly enlarges the mismatch and the residual stress. The dislocations weaken the effect of shear for the further creep stage, resulting in the decrease of the mismatch and relaxation of the residual stress. Those findings add some helpful understanding into the microstructure-performance relationship in the SC nickel-based superalloy, which might provide the insight to materials design and applications.

  1. Residual strains and microstructure development in single and sequential double sided friction stir welds in RQT-701 steel

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, S.J. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)], E-mail: simon.barnes-2@manchester.ac.uk; Steuwer, A. [FaME38, ILL ESRF, 6 rue J.Horowitz, 38042 Grenoble, Cedex (France); University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Mahawish, S. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Johnson, R. [TWI Yorkshire, Wallis Way, Catcliffe, Rotherham S60 5TZ (United Kingdom); Withers, P.J. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)

    2008-09-25

    Single and double sided partial penetration friction stir butt welds, in a rolled, quenched and tempered steel (RQT-701), were produced at The Welding Institute (TWI) under controlled process conditions. The residual strain distributions in the longitudinal and transverse directions have been measured using energy dispersive synchrotron X-ray diffraction. The measured strains were indicative of longitudinal tensile residual stresses at levels greater than the 0.2% yield stress of the parent metal in both the single and double pass welds. In both cases, the maximum tensile strain was found in the parent metal at the boundary of the heat affected zone (HAZ). Microstructural analysis of the welds was carried out using optical microscopy and hardness variations were also mapped across the weld-plate cross-section. The maximum hardness was observed in the mixed bainite/martensite structure of the weld nugget on the advancing side of the stir zone. The minimum hardness was observed in the HAZ.

  2. Residual strains and microstructure development in single and sequential double sided friction stir welds in RQT-701 steel

    International Nuclear Information System (INIS)

    Barnes, S.J.; Steuwer, A.; Mahawish, S.; Johnson, R.; Withers, P.J.

    2008-01-01

    Single and double sided partial penetration friction stir butt welds, in a rolled, quenched and tempered steel (RQT-701), were produced at The Welding Institute (TWI) under controlled process conditions. The residual strain distributions in the longitudinal and transverse directions have been measured using energy dispersive synchrotron X-ray diffraction. The measured strains were indicative of longitudinal tensile residual stresses at levels greater than the 0.2% yield stress of the parent metal in both the single and double pass welds. In both cases, the maximum tensile strain was found in the parent metal at the boundary of the heat affected zone (HAZ). Microstructural analysis of the welds was carried out using optical microscopy and hardness variations were also mapped across the weld-plate cross-section. The maximum hardness was observed in the mixed bainite/martensite structure of the weld nugget on the advancing side of the stir zone. The minimum hardness was observed in the HAZ

  3. Detecting single-abasic residues within a DNA strand immobilized in a biological nanopore using an integrated CMOS sensor.

    Science.gov (United States)

    Kim, Jungsuk; Maitra, Raj D; Pedrotti, Ken; Dunbar, William B

    2013-02-01

    In this paper, we demonstrate the application of a novel current-measuring sensor (CMS) customized for nanopore applications. The low-noise CMS is fabricated in a 0.35μm CMOS process and is implemented in experiments involving DNA captured in an α-hemolysin (α-HL) nanopore. Specifically, the CMS is used to build a current amplitude map as a function of varying positions of a single-abasic residue within a homopolymer cytosine single-stranded DNA (ssDNA) that is captured and held in the pore. Each ssDNA is immobilized using a biotin-streptavidin linkage. Five different DNA templates are measured and compared: one all-cytosine ssDNA, and four with a single-abasic residue substitution that resides in or near the ~1.5nm aperture of the α-HL channel when the strand is immobilized. The CMOS CMS is shown to resolves the ~5Å displacements of the abasic residue within the varying templates. The demonstration represents an advance in application-specific circuitry that is optimized for small-footprint nanopore applications, including genomic sequencing.

  4. Characterization of Solids in Residual Wastes from Single-Shell Tanks at the Hanford Site, Washington, USA - 9277

    International Nuclear Information System (INIS)

    Krupka, Kenneth M.; Cantrell, Kirk J.; Schaef, Herbert T.; Arey, Bruce W.; Heald, Steve M.; Deutsch, William J.; Lindberg, Michael J.

    2009-01-01

    Solid-phase characterization methods have been used in an ongoing study of residual wastes (i.e., waste remaining after final retrieval operations) from the underground single-shell storage tanks 241-C-103, 241-C-106, 241-C-202, 241-C-203, and 241-S-112 at the U.S. Department of Energy's Hanford Site in Washington State. The results of studies completed to date show significant variability in the compositions of those residual wastes and the compositions, morphologies, and crystallinities of the individual phases that make up these wastes. These differences undoubtedly result from the various waste types stored and transferred in and out each tank and the sluicing and retrieval operations used for waste retrieval. Our studies indicate that these residual wastes are chemically-complex assemblages of crystalline and amorphous solids that contain contaminants as discrete phases and/or co-precipitated within oxide phases. Depending on the specific tank, various solids (e.g., gibbsite; boehmite; dawsonite; cancrinite; Fe oxides such as hematite, goethite, and maghemite; rhodochrosite; lindbergite; whewellite; nitratine; and numerous amorphous or poorly crystalline phases) have been identified by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy in residual wastes studied to date. Our studies also show that contact of residual wastes with Ca(OH)2- and CaCO3-saturated aqueous solutions, which were used as surrogates for the compositions of pore-fluid leachants derived from young and aged cements respectively, may alter the compositions of solid phases present in the contacted wastes. Fe oxides/hydroxides have been identified in all residual wastes studied to date. They occur in these wastes as discrete particles, particles intergrown within a matrix of other phases, and surface coatings on other particles or particle aggregates. These Fe oxides/hydroxides typically contain trace concentrations of other transition metals, such Cr, Mn

  5. [Acute tryptophan depletion in eating disorders].

    Science.gov (United States)

    Díaz-Marsa, M; Lozano, C; Herranz, A S; Asensio-Vegas, M J; Martín, O; Revert, L; Saiz-Ruiz, J; Carrasco, J L

    2006-01-01

    This work describes the rational bases justifying the use of acute tryptophan depletion technique in eating disorders (ED) and the methods and design used in our studies. Tryptophan depletion technique has been described and used in previous studies safely and makes it possible to evaluate the brain serotonin activity. Therefore it is used in the investigation of hypotheses on serotonergic deficiency in eating disorders. Furthermore, and given the relationship of the dysfunctions of serotonin activity with impulsive symptoms, the technique may be useful in biological differentiation of different subtypes, that is restrictive and bulimic, of ED. 57 female patients with DSM-IV eating disorders and 20 female controls were investigated with the tryptophan depletion test. A tryptophan-free amino acid solution was administered orally after a two-day low tryptophan diet to patients and controls. Free plasma tryptophan was measured at two and five hours following administration of the drink. Eating and emotional responses were measured with specific scales for five hours following the depletion. A study of the basic characteristics of the personality and impulsivity traits was also done. Relationship of the response to the test with the different clinical subtypes and with the temperamental and impulsive characteristics of the patients was studied. The test was effective in considerably reducing plasma tryptophan in five hours from baseline levels (76%) in the global sample. The test was well tolerated and no severe adverse effects were reported. Two patients withdrew from the test due to gastric intolerance. The tryptophan depletion test could be of value to study involvement of serotonin deficits in the symptomatology and pathophysiology of eating disorders.

  6. Sequence and features of the tryptophan operon of Vibrio parahemolyticus.

    Science.gov (United States)

    Crawford, I P; Han, C Y; Silverman, M

    1991-01-01

    The nucleotide sequence of the trp operon of the marine enteric bacterium Vibrio parahemolyticus is presented. The gene order E, G, D, C(F), B, A is identical to that of other enterics. The structural genes of the operon are preceded by a long leader region encoding a 41-residue peptide containing five tryptophan residues. The organization of the leader region suggests that transcription of the operon is subject to attenuation control. The promoter-operator region of the V. parahemolyticus trp operon is almost identical to the corresponding promoter-operator of E. coli. The similarities suggest that promoter strength and operator function are identical in the two species, and that transcription initiation is regulated by repression. The operon appears to lack the internal promoter within trpD that is common in terrestrial enteric species.

  7. A Single Residue in Ebola Virus Receptor NPC1 Influences Cellular Host Range in Reptiles

    Science.gov (United States)

    2016-09-07

    VH-2) is resistant to infection in an NPC1-36   dependent manner . We found that VH-2 cells are resistant to EBOV infection because the Rus-37...infection in a host species-dependent manner (24). Here, we demonstrate that an adjacent 89   residue, 503, highly conserved in the domain C of NPC1...Tyr sequence 194   change at residue 503 might influence EBOV GPCL–NPC1 binding in a bidirectional manner . 195   Accordingly, we expressed and

  8. Single particle measurements of the chemical composition of cirrus ice residue during CRYSTAL-FACE

    Science.gov (United States)

    Cziczo, D. J.; Murphy, D. M.; Hudson, P. K.; Thomson, D. S.

    2004-02-01

    The first real-time, in situ, investigation of the chemical composition of the residue of cirrus ice crystals was performed during July 2002. This study was undertaken on a NASA WB-57F high-altitude research aircraft as part of CRYSTAL-FACE, a field campaign which sought to further our understanding of the relation of clouds, water vapor, and climate by characterizing, among other parameters, anvil cirrus formed about the Florida peninsula. A counter flow virtual impactor (CVI) was used to separate cirrus ice from the unactivated interstitial aerosol particles and evaporate condensed-phase water. Residual material, on a crystal-by-crystal basis, was subsequently analyzed using the NOAA Aeronomy Laboratory's Particle Analysis by Laser Mass Spectrometry (PALMS) instrument. Sampling was performed from 5 to 15 km altitude and from 12° to 28° north latitude within cirrus originating over land and ocean. Chemical composition measurements provided several important results. Sea salt was often incorporated into cirrus, consistent with homogeneous ice formation by aerosol particles from the marine boundary layer. Size measurements showed that large particles preferentially froze over smaller ones. Meteoritic material was found within ice crystals, indicative of a relation between stratospheric aerosol particles and tropospheric clouds. Mineral dust was the dominant residue observed in clouds formed during a dust transport event from the Sahara, consistent with a heterogeneous freezing mechanism. These results show that chemical composition and size are important determinants of which aerosol particles form cirrus ice crystals.

  9. Construction of a recombinant single chain antibody recognizing nonreducing terminal mannose residues applicable to immunohistochemistry.

    Science.gov (United States)

    Yuasa, Noriyuki; Iida, Noriko; Sakaue, Hiroyuki; Zhang, Wei; Wilczynski, Sharon; Fujita-Yamaguchi, Yoko

    2007-10-01

    We recently reported characterization of 25 clones isolated from a phage library displaying human scFvs using a neoglycolipid Man3-DPPE, which was synthesized from mannotriose (Man3) and dipalmitoylphosphatidylethanolamine (DPPE). Of those, 5A3 scFv was successfully expressed and purified as a humanized scFv-Fc form (Sakai et al., Biochemistry 46:253, 2007, Zhang et al. ibid 263). To carry out immunohistochemistry (IHC) in human tissues, a HA tag sequence was introduced to the 5A3 scFv-Fc gene and the resulting construct was transfected to murine myeloma NS0 cells. The 5A3 scFv-Fc protein expressed was affinity-purified. Sodium dodecyl sulfate polyacrylamide gel electrophoresis under nonreducing and reducing conditions and enzyme-linked immunosorbent assay confirmed that 5A3 scFv-Fc protein is dimeric and retained the ability to recognize nonreducing terminal mannose residues. IHC staining of non-neoplastic tissues by this recombinant antibody revealed that no immunoreactivity was detectable in most of 16 tissues examined. Exceptions were found in IHC staining of kidney and pancreas, which demonstrated clear staining of proximal tubules and islet of Langerhans, respectively. These results demonstrated that nonreducing terminal mannose residues are not usually present under normal physiological conditions. This study thus provided a potentially useful tool for examination of the nonreducing terminal mannose residues, which may become exposed under certain pathophysiologycal conditions.

  10. Dendritic biomimicry: microenvironmental hydrogen-bonding effects on tryptophan fluorescence.

    Science.gov (United States)

    Koenig, S; Müller, L; Smith, D K

    2001-03-02

    Two series of dendritically modified tryptophan derivatives have been synthesised and their emission spectra measured in a range of different solvents. This paper presents the syntheses of these novel dendritic structures and discusses their emission spectra in terms of both solvent and dendritic effects. In the first series of dendrimers, the NH group of the indole ring is available for hydrogen bonding, whilst in the second series, the indole NH group has been converted to NMe. Direct comparison of the emission wavelengths of analogous NH and NMe derivatives indicates the importance of the Kamlet-Taft solvent beta3 parameter, which reflects the ability of the solvent to accept a hydrogen bond from the NH group, an effect not possible for the NMe series of dendrimers. For the NH dendrimers, the attachment of a dendritic shell to the tryptophan subunit leads to a red shift in emission wavelength. This dendritic effect only operates in non-hydrogen-bonding solvents. For the NMe dendrimers, however, the attachment of a dendritic shell has no effect on the emission spectra of the indole ring. This proves the importance of hydrogen bonding between the branched shell and the indole NH group in causing the dendritic effect. This is the first time a dendritic effect has been unambiguously assigned to individual hydrogen-bonding interactions and indicates that such intramolecular interactions are important in dendrimers, just as they are in proteins. Furthermore, this paper sheds light on the use of tryptophan residues as a probe of the microenvironment within proteins--in particular, it stresses the importance of hydrogen bonds formed by the indole NH group.

  11. Tuning electronic transport via hepta-alanine peptides junction by tryptophan doping.

    Science.gov (United States)

    Guo, Cunlan; Yu, Xi; Refaely-Abramson, Sivan; Sepunaru, Lior; Bendikov, Tatyana; Pecht, Israel; Kronik, Leeor; Vilan, Ayelet; Sheves, Mordechai; Cahen, David

    2016-09-27

    Charge migration for electron transfer via the polypeptide matrix of proteins is a key process in biological energy conversion and signaling systems. It is sensitive to the sequence of amino acids composing the protein and, therefore, offers a tool for chemical control of charge transport across biomaterial-based devices. We designed a series of linear oligoalanine peptides with a single tryptophan substitution that acts as a "dopant," introducing an energy level closer to the electrodes' Fermi level than that of the alanine homopeptide. We investigated the solid-state electron transport (ETp) across a self-assembled monolayer of these peptides between gold contacts. The single tryptophan "doping" markedly increased the conductance of the peptide chain, especially when its location in the sequence is close to the electrodes. Combining inelastic tunneling spectroscopy, UV photoelectron spectroscopy, electronic structure calculations by advanced density-functional theory, and dc current-voltage analysis, the role of tryptophan in ETp is rationalized by charge tunneling across a heterogeneous energy barrier, via electronic states of alanine and tryptophan, and by relatively efficient direct coupling of tryptophan to a Au electrode. These results reveal a controlled way of modulating the electrical properties of molecular junctions by tailor-made "building block" peptides.

  12. Tryptophan exposure and accessibility in the chitooligosaccharide-specific phloem exudate lectin from pumpkin (Cucurbita maxima). A fluorescence study.

    Science.gov (United States)

    Narahari, Akkaladevi; Swamy, Musti J

    2009-10-06

    The exposure and accessibility of the tryptophan residues in the chitooligosaccharide-specific pumpkin (Cucurbita maxima) phloem exudate lectin (PPL) have been investigated by fluorescence spectroscopy. The emission lambda(max) of native PPL, seen at 338nm was red-shifted to 348nm upon denaturation by 6M Gdn.HCl in the presence of 10mM beta-mercaptoethanol, indicating near complete exposure of the tryptophan residues to the aqueous medium, whereas a blue-shift to 335nm was observed in the presence of saturating concentrations of chitotriose, suggesting that ligand binding leads to a decrease in the solvent exposure of the tryptophan residues. The extent of quenching was maximum with the neutral molecule, acrylamide whereas the ionic species, iodide and Cs(+) led to significantly lower quenching, which could be attributed to the presence of charged amino acid residues in close proximity to some of the tryptophan residues. The Stern-Volmer plot for acrylamide was linear for native PPL and upon ligand binding, but became upward curving upon denaturation, indicating that the quenching occurs via a combination of static and dynamic mechanisms. In time-resolved fluorescence experiments, the decay curves could be best fit to biexponential patterns, for native protein, in the presence of ligand and upon denaturation. In each case both lifetimes systematically decreased with increasing acrylamide concentrations, indicating that quenching occurs predominantly via a dynamic process.

  13. Single-Residue Sensitivity in Neutron Reflectivity and Resonant X-ray Reflectivity from Langmuir Monolayers of Synthetic Peptides

    Science.gov (United States)

    Strzalka, Joseph; Satija, Sushil; Dimasi, Elaine; Kuzmenko, Ivan; Gog, Thomas; Blasie, J. Kent

    2004-03-01

    Labeling groups with ^2H to distinguish them in the scattering length density (SLD) profile constitutes the chief advantage of neutron reflectivity (NR) in studying Langmuir monolayers (LM) of lipids and proteins. Solid phase synthesis (SPPS) permits the labeling of a single residue in a peptide. Recent work demonstrates the sensitivity of NR to single ^2H-labeled residues in LM of vectorially oriented α -helical bundle peptides. NR requires comparison of isomorphic samples of all-^1H and ^2H-labeled peptides. Alternately, resonant x-ray reflectivity (RXR) uses only one sample. RXR exploits energy-dependent changes in the scattering factor from heavy atoms to distinguish them within the SLD profile. Peptides may be labeled by SPPS (e.g. Br-Phe), or may have inherent labels (e.g. Fe in heme proteins). As test cases, we studied LM of Br-labeled lipids and peptides with RXR. Both approaches require a model-independent means of obtaining SLD profiles from the reflectivity data. We have applied box-refinement to obtain the gradient SLD profile. This is fit uniquely with a sum of Gaussians and integrated analytically [Blasie et al., PRB 67 224201 (2003)] to provide the SLD profile. Label positions can then be determined to sub-Ångstrom accuracy. This work supported by the NIH (GM55876).

  14. Early Posttransplant Tryptophan Metabolism Predicts Long-term Outcome of Human Kidney Transplantation

    NARCIS (Netherlands)

    Vavrincova-Yaghi, Diana; Seelen, Marc A.; Kema, Ido P.; Deelman, Leo E.; Heuvel, van den Marius; Breukelman, Henk; Van den Eynde, Benoit J.; Henning, Rob H.; van Goor, Harry; Sandovici, Maria

    Background. Chronic transplant dysfunction (CTD) is the leading cause of long-term loss of the renal allograft. So far, no single test is available to reliably predict the risk for CTD. Monitoring of tryptophan (trp) metabolism through indoleamine 2.3-dioxygenase (IDO) has been previously proposed

  15. Assessment of single-shell tank residual-liquid issues at Hanford Site, Washington

    International Nuclear Information System (INIS)

    Murthy, K.S.; Stout, L.A.; Napier, B.A.; Reisenauer, A.E.; Landstrom, D.K.

    1983-06-01

    This report provides an assessment of the overall effectiveness and implications of jet pumping the interstitial liquids (IL) from single-shell tanks at Hanford. The jet-pumping program, currently in progress at Hanford, involves the planned removal of IL contained in 89 of the 149 single-shell tanks and its transfer to double-shell tanks after volume reduction by evaporation. The purpose of this report is to estimate the public and worker doses associated with (1) terminating pumping immediately, (2) pumping to a 100,000-gal limit per tank, (3) pumping to a 50,000-gal limit per tank, and (4) pumping to the maximum practical liquid removal level of 30,000 gal. Assessment of the cost-effectiveness of these various levels of pumping in minimizing any undue health and safety risks to the public or worker is also presented

  16. Allergy medication in Japanese volunteers: treatment effect of single doses on nocturnal sleep architecture and next day residual effects.

    Science.gov (United States)

    Boyle, Julia; Eriksson, Malin; Stanley, Neil; Fujita, Tomoe; Kumagi, Yuji

    2006-07-01

    To evaluate the acute effects of two histamine H(1)-receptor antagonists on nocturnal sleep architecture and on next day cognitive function and psychomotor performance. This was a single-site, randomized, double-blind, 3-way crossover study, comparing the effects of a single dose of chlorpheniramine (6 mg), fexofenadine (120 mg) and placebo in 18 healthy (male and female) Japanese volunteers aged 20-55 years. Volunteers were resident for 3 days and each period was separated by a minimum 5-day washout period. The three treatments were administered at 23.00 h. Overnight sleep was measured from 23.00 h to 07.00 h using polysomnography. Residual effects were studied at 07.00 h and 9.00 h the next morning, with the latency to sleep (sleep latency test) measured at 09.30 h. Compared with placebo, chlorpheniramine increased the latencies to sleep onset and rapid eye movement (REM) sleep (p < or = 0.05 for both), and reduced the duration of REM sleep (p residual effects the next morning were concerned there were decrements in performance with chlorpheniramine, but not with fexofenadine. Chlorpheniramine 6 mg impaired divided attention (p < 0.001), vigilance (p < 0.05), working memory (p < 0.0001) and sensori-motor performance (p < 0.01), and the latency to daytime sleep was reduced (p < 0.0001). Six adverse events possibly related to study medication were reported during the study, three of which were related to placebo, two to fexofenadine and one to chlorpheniramine. These findings suggest that a single nocturnal dose of fexofenadine has advantages over the first-generation antihistamine chlorpheniramine, being free of disruption of night-time sleep and detrimental effects on cognitive performance the next day. It is likely that this advantage will remain with chronic ingestion, but this would need to be confirmed.

  17. Tryptophan-induced pathogenesis of breast cancer

    African Journals Online (AJOL)

    Aims: To investigate the pathogenesis of breast cancer through targeted metabolomics of amino acids ... Furthermore, the biological function of tryptophan was determined through determining the influence ... profiling all the small molecules in the biosamples (e.g., .... is a promising therapeutic agent for pancreatic cancer7.

  18. "Ico-Alone" single nocturnal exchange to initiate peritoneal dialysis in patients with residual renal function-Five year, single centre experience

    Directory of Open Access Journals (Sweden)

    T Jeloka

    2013-01-01

    Full Text Available We analyzed the outcome of incremental dialysis with single nocturnal icodextrin exchange peritoneal dialysis (PD as the initial treatment for end-stage kidney failure in patients who have significant residual renal function. All adult patients opting for PD as renal replacement therapy, having residual renal function, and urinary KT/V of 1.0 were offered incremental dialysis with single nocturnal icodextrin exchange as initial treatment. Adequacy of dialysis was calculated at 1, 3, and 6 months and then 6 monthly. Patients were shifted to conventional PD if short of adequacy or if clinically indicated. Median period on "Ico-alone," peritonitis, exit site infection rates, and patient survival, while on this protocol, were calculated. These outcomes were compared with the cohort of contemporary patients on conventional PD. Thirteen patients were initiated on "Ico-alone" dialysis between October 2006 and October 2011. The baseline characteristics were similar when compared with cohort of conventional PD patients, except urine volume, which was more in "Ico-alone" group (1265 ± 316 vs. 551 ± 504, P = 0.000. Total KT/V at 3 months (1.63 ± 0.6 vs. 1.7 ± 0.2, P = 0.6 and at 1 year (1.64 ± 0.5 vs. 1.53 ± 0.3, P = 0.6 was similar to the cohort of conventional PD patients. Median period on "Ico-alone" was 9.6 months. Peritonitis rate was 1 episode in 56.22 vs 25.29 patient-months and exit site infection was 1 episode in 56.2 vs 189.71 patient-months in "Ico-alone" and conventional group, respectively. Patient survival was 42.84 months in "Ico-alone′ vs 25.29 months in conventional dialysis ( P = 0.01. In conclusion, single icodextrin exchange offers adequate dialysis in patients with residual renal function (KT/V = 1 for a median period of 9 months.

  19. Simulation investigation of thermal phase transformation and residual stress in single pulse EDM of Ti-6Al-4V

    Science.gov (United States)

    Tang, Jiajing; Yang, Xiaodong

    2018-04-01

    The thermal phase transformation and residual stress are ineluctable in the electrical discharge machining (EDM) process, and they will greatly affect the working performances of the machined surface. This paper presents a simulation study on the thermal phase transformation and residual stress in single-pulse EDM of Ti-6Al-4V, which is the most popular titanium alloy in fields such as aircraft engine and some other leading industries. A multi-physics model including thermal, hydraulic, metallography and structural mechanics was developed. Based on the proposed model, the thickness and metallographic structure of the recast layer and heat affected layer (HAZ) were investigated. The distribution and characteristics of residual stress around the discharge crater were obtained. The recast layer and HAZ at the center of crater are found to be the thinnest, and their thicknesses gradually increase approaching the periphery of the crater. The recast layer undergoes a complete α‧ (martensitic) transformation, while the HAZ is mainly composed by the α  +  β  +  α‧ three-phase microstructure. Along the depth direction of crater, the Von Mises stress increases first and then decreases, reaching its maximal value near the interface of recast layer and HAZ. In the recast layer, both compressive stress component and tensile stress component are observed. ANOVA results showed that the influence of discharge current on maximal tensile stress is more significant than that of pulse duration, while the pulse duration has more significant influence on average thickness of the recast layer and the depth location of the maximal tensile stress. The works conducted in this study will help to evaluate the quality and integrity of EDMed surface, especially when the non-destructive testing is difficult to achieve.

  20. A residual-based a posteriori error estimator for single-phase Darcy flow in fractured porous media

    KAUST Repository

    Chen, Huangxin

    2016-12-09

    In this paper we develop an a posteriori error estimator for a mixed finite element method for single-phase Darcy flow in a two-dimensional fractured porous media. The discrete fracture model is applied to model the fractures by one-dimensional fractures in a two-dimensional domain. We consider Raviart–Thomas mixed finite element method for the approximation of the coupled Darcy flows in the fractures and the surrounding porous media. We derive a robust residual-based a posteriori error estimator for the problem with non-intersecting fractures. The reliability and efficiency of the a posteriori error estimator are established for the error measured in an energy norm. Numerical results verifying the robustness of the proposed a posteriori error estimator are given. Moreover, our numerical results indicate that the a posteriori error estimator also works well for the problem with intersecting fractures.

  1. Contaminant Release from Residual Waste in Closed Single-Shell Tanks and Other Waste Forms Associated with the Tanks

    International Nuclear Information System (INIS)

    Deutsch, William J.

    2008-01-01

    This chapter describes the release of contaminants from the various waste forms that are anticipated to be associated with closure of the single-shell tanks. These waste forms include residual sludge or saltcake that will remain in the tanks after waste retrieval. Other waste forms include engineered glass and cementitious materials as well as contaminated soil impacted by previous tank leaks. This chapter also describes laboratory testing to quantify contaminant release and how the release data are used in performance/risk assessments for the tank waste management units and the onsite waste disposal facilities. The chapter ends with a discussion of the surprises and lessons learned to date from the testing of waste materials and the development of contaminant release models

  2. Tryptophan Transport in Human Fibroblast Cells—A Functional Characterization

    Directory of Open Access Journals (Sweden)

    Ravi Vumma

    2011-01-01

    Full Text Available There are indications that serotonergic neurotransmission is disturbed in several psychiatric disorders. One explanation may be disturbed transport of tryptophan (precursor for serotonin synthesis across cell membranes. Human fibroblast cells offer an advantageous model to study the transport of amino acids across cell membranes, since they are easy to propagate and the environmental factors can be controlled. The aim of this study was to functionally characterize tryptophan transport and to identify the main transporters of tryptophan in fibroblast cell lines from healthy controls. Tryptophan kinetic parameters ( V max and K m at low and high concentrations were measured in fibroblasts using the cluster tray method. Uptake of 3 H (5-L-tryptophan at different concentrations in the presence and absence of excess concentrations of inhibitors or combinations of inhibitors of amino acid transporters were also measured. Tryptophan transport at high concentration (0.5 mM had low affinity and high V max and the LAT1 isoform of system-L was responsible for approximately 40% of the total uptake of tryptophan. In comparison, tryptophan transport at low concentration (50 nM had higher affinity, lower V max and approximately 80% of tryptophan uptake was transported by system-L with LAT1 as the major isoform. The uptake of tryptophan at the low concentration was mainly sodium (Na + dependent, while uptake at high substrate concentration was mainly Na + independent. A series of different transporter inhibitors had varying inhibitory effects on tryptophan uptake. This study indicates that tryptophan is transported by multiple transporters that are active at different substrate concentrations in human fibroblast cells. The tryptophan transport trough system-L was mainly facilitated by the LAT1 isoform, at both low and high substrate concentrations of tryptophan.

  3. A single gp120 residue can affect HIV-1 tropism in macaques.

    Directory of Open Access Journals (Sweden)

    Gregory Q Del Prete

    2017-09-01

    Full Text Available Species-dependent variation in proteins that aid or limit virus replication determines the ability of lentiviruses to jump between host species. Identifying and overcoming these differences facilitates the development of animal models for HIV-1, including models based on chimeric SIVs that express HIV-1 envelope (Env glycoproteins, (SHIVs and simian-tropic HIV-1 (stHIV strains. Here, we demonstrate that the inherently poor ability of most HIV-1 Env proteins to use macaque CD4 as a receptor is improved during adaptation by virus passage in macaques. We identify a single amino acid, A281, in HIV-1 Env that consistently changes during adaptation in macaques and affects the ability of HIV-1 Env to use macaque CD4. Importantly, mutations at A281 do not markedly affect HIV-1 Env neutralization properties. Our findings should facilitate the design of HIV-1 Env proteins for use in non-human primate models and thus expedite the development of clinically relevant reagents for testing interventions against HIV-1.

  4. Conformation-specific spectroscopy of capped glutamine-containing peptides: role of a single glutamine residue on peptide backbone preferences.

    Science.gov (United States)

    Walsh, Patrick S; Dean, Jacob C; McBurney, Carl; Kang, Hyuk; Gellman, Samuel H; Zwier, Timothy S

    2016-04-28

    The conformational preferences of a series of short, aromatic-capped, glutamine-containing peptides have been studied under jet-cooled conditions in the gas phase. This work seeks a bottom-up understanding of the role played by glutamine residues in directing peptide structures that lead to neurodegenerative diseases. Resonant ion-dip infrared (RIDIR) spectroscopy is used to record single-conformation infrared spectra in the NH stretch, amide I and amide II regions. Comparison of the experimental spectra with the predictions of calculations carried out at the DFT M05-2X/6-31+G(d) level of theory lead to firm assignments for the H-bonding architectures of a total of eight conformers of four molecules, including three in Z-Gln-OH, one in Z-Gln-NHMe, three in Ac-Gln-NHBn, and one in Ac-Ala-Gln-NHBn. The Gln side chain engages actively in forming H-bonds with nearest-neighbor amide groups, forming C8 H-bonds to the C-terminal side, C9 H-bonds to the N-terminal side, and an amide-stacked geometry, all with an extended (C5) peptide backbone about the Gln residue. The Gln side chain also stabilizes an inverse γ-turn in the peptide backbone by forming a pair of H-bonds that bridge the γ-turn and stabilize it. Finally, the entire conformer population of Ac-Ala-Gln-NHBn is funneled into a single structure that incorporates the peptide backbone in a type I β-turn, stabilized by the Gln side chain forming a C7 H-bond to the central amide group in the β-turn not otherwise involved in a hydrogen bond. This β-turn backbone structure is nearly identical to that observed in a series of X-(AQ)-Y β-turns in the protein data bank, demonstrating that the gas-phase structure is robust to perturbations imposed by the crystalline protein environment.

  5. Dietary tryptophan intake and suicide rate in industrialized nations.

    Science.gov (United States)

    Voracek, Martin; Tran, Ulrich S

    2007-03-01

    The objective of this study was to assess the ecological association of dietary tryptophan intake and suicide rates across industrialized nations. Tryptophan, an essential amino acid, is the rate-limiting precursor of serotonin biosynthesis. The serotonergic system has been strongly implicated in the neurobiology of suicide. Contemporary male and female suicide rates for the general population (42 countries) and the elderly (38 countries) were correlated with national estimates of dietary tryptophan intake. Measures of tryptophan intake were significantly negatively associated to national suicide rates. Controlling for national affluence, total alcohol consumption and happiness levels slightly attenuated these associations, but left all of them negative. The effect is an ecological (group-level) finding. Estimated per capita tryptophan supply is only a proxy for actual consumption. Developed nations ranking high in dietary tryptophan intake rank low in suicide rates, independent of national wealth, alcohol intake and happiness.

  6. Tryptophan and kynurenine determination in human hair by liquid chromatography.

    Science.gov (United States)

    Dario, Michelli F; Freire, Thamires Batello; Pinto, Claudinéia Aparecida Sales de Oliveira; Prado, María Segunda Aurora; Baby, André R; Velasco, Maria Valéria R

    2017-10-15

    Tryptophan, an amino acid found in hair proteinaceous structure is used as a marker of hair photodegradation. Also, protein loss caused by several chemical/physical treatments can be inferred by tryptophan quantification. Kynurenine is a photo-oxidation product of tryptophan, expected to be detected when hair is exposed mainly to UVB (290-320nm) radiation range. Tryptophan from hair is usually quantified directly as a solid or after alkaline hydrolysis, spectrofluorimetrically. However, these types of measure are not sufficiently specific and present several interfering substances. Thus, this work aimed to propose a quantification method for both tryptophan and kynurenine in hair samples, after alkali hydrolysis process, by using high-performance liquid chromatography (HPLC) with fluorimetric and UV detection. The tryptophan and kynurenine quantification method was developed and validated. Black, white, bleached and dyed (blond and auburn) hair tresses were used in this study. Tryptophan and kynurenine were separated within ∼9min by HPLC. Both black and white virgin hair samples presented similar concentrations of tryptophan, while bleaching caused a reduction in the tryptophan content as well as dyeing process. Unexpectedly, UV/vis radiation did not promote significantly the conversion of tryptophan into its photo-oxidation product and consequently, kynurenine was not detected. Thus, this works presented an acceptable method for quantification of tryptophan and its photooxidation metabolite kynurenine in hair samples. Also, the results indicated that bleaching and dyeing processes promoted protein/amino acids loss but tryptophan is not extensively degraded in human hair by solar radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Evolution and function of the Mycoplasma hyopneumoniae peroxiredoxin, a 2-Cys-like enzyme with a single Cys residue.

    Science.gov (United States)

    Gonchoroski, Taylor; Virginio, Veridiana G; Thompson, Claudia E; Paes, Jéssica A; Machado, Cláudio X; Ferreira, Henrique B

    2017-04-01

    The minimal genome of the mollicute Mycoplasma hyopneumoniae, the etiological agent of porcine enzootic pneumonia, encodes a limited repertoire of antioxidant enzymes that include a single and atypical peroxiredoxin (MhPrx), whose evolution and function were studied here. MhPrx has only one catalytic cysteine, in contrast with some of its possible ancestors (2-Cys peroxiredoxins), which have two. Although it is more similar to 2-Cys orthologs, MhPrx can still function with a single peroxidatic cysteine (Cys P ), using non-thiolic electron donors to reduce it. Therefore, MhPrx could be a representative of a possible group of 2-Cys peroxiredoxins, which have lost the resolving cysteine (Cys R ) residue without losing their catalytic properties. To further investigate MhPrx evolution, we performed a comprehensive phylogenetic analysis in the context of several bacterial families, including Prxs belonging to Tpx and AhpE families, shedding light on the evolutionary history of Mycoplasmataceae Prxs and giving support to the hypothesis of a relatively recent loss of the Cys R within this family. Moreover, mutational analyses provided insights into MhPrx function with one, two, or without catalytic cysteines. While removal of the MhPrx putative Cys P caused complete activity loss, confirming its catalytic role, the introduction of a second cysteine in a site correspondent to that of the Cys R of a 2-Cys orthologue, as in the MhPrx supposed ancestral form, was compatible with enzyme activity. Overall, our phylogenetic and mutational studies support that MhPrx recently diverged from a 2-Cys Prx ancestor and pave the way for future studies addressing structural, functional, and evolutive aspects of peroxiredoxin subfamilies in Mollicutes and other bacteria.

  8. Central fatigue and nycthemeral change of serum tryptophan and serotonin in the athletic horse

    Directory of Open Access Journals (Sweden)

    Percipalle Maurizio

    2005-04-01

    Full Text Available Abstract Background The serotonergic system is associated with numerous brain functions, including the resetting of the mammalian circadian clock. The synthesis and metabolism of 5-HT in the brain increases in response to exercise and is correlated with high levels of blood-borne tryptophan (TRP. The present investigation was aimed at testing the existence of a daily rhythm of TRP and 5-HT in the blood of athletic horses. Methods Blood samples from 5 Thoroughbred mares were collected at 4-hour intervals for 48 hours (starting at 08:00 hours on day 1 and finishing at 4:00 on day 2 via an intravenous cannula inserted into the jugular vein. Tryptophan and serotonin concentrations were assessed by HPLC. Data analysis was conducted by one-way repeated measures analysis of variance (ANOVA and by the single cosinor method. Results ANOVA showed a highly significant influence of time both on tryptophan and on serotonin, in all horses, on either day, with p values Conclusion The results showed that serotonin and tryptophan blood levels undergo nycthemeral variation with typical evening acrophases. These results enhance the understanding of the athlete horse's chronoperformance and facilitate the establishment of training programs that take into account the nycthemeral pattern of aminoacids deeply involved in the onset of central fatigue.

  9. Control of peptide nanotube diameter by chemical modifications of an aromatic residue involved in a single close contact

    Science.gov (United States)

    Tarabout, Christophe; Roux, Stéphane; Gobeaux, Frédéric; Fay, Nicolas; Pouget, Emilie; Meriadec, Cristelle; Ligeti, Melinda; Thomas, Daniel; IJsselstijn, Maarten; Besselievre, François; Buisson, David-Alexandre; Verbavatz, Jean-Marc; Petitjean, Michel; Valéry, Céline; Perrin, Lionel; Rousseau, Bernard; Artzner, Franck; Paternostre, Maité; Cintrat, Jean-Christophe

    2011-01-01

    Supramolecular self-assembly is an attractive pathway for bottom-up synthesis of novel nanomaterials. In particular, this approach allows the spontaneous formation of structures of well-defined shapes and monodisperse characteristic sizes. Because nanotechnology mainly relies on size-dependent physical phenomena, the control of monodispersity is required, but the possibility of tuning the size is also essential. For self-assembling systems, shape, size, and monodispersity are mainly settled by the chemical structure of the building block. Attempts to change the size notably by chemical modification usually end up with the loss of self-assembly. Here, we generated a library of 17 peptides forming nanotubes of monodisperse diameter ranging from 10 to 36 nm. A structural model taking into account close contacts explains how a modification of a few Å of a single aromatic residue induces a fourfold increase in nanotube diameter. The application of such a strategy is demonstrated by the formation of silica nanotubes of various diameters. PMID:21518895

  10. Characterization of an endoprotease from rat small intestinal mucosal secretory granules which generates somatostatin-28 from prosomatostatin by cleavage after a single arginine residue

    NARCIS (Netherlands)

    Beinfeld, M. C.; Bourdais, J.; Kuks, P.; Morel, A.; Cohen, P.

    1989-01-01

    We have extracted, characterized, and partially purified an enzyme from secretory granules from rat small intestinal mucosa which cleaves a synthetic prosomatostatin substrate on the carboxyl side of a single arginine residue. This substrate Leu-Gln-Arg-Ser-Ala-Asn-Ser-NH2 contains the monobasic

  11. Tryptophan depletion affects compulsive behaviour in rats

    DEFF Research Database (Denmark)

    Merchán, A; Navarro, S V; Klein, A B

    2017-01-01

    investigated whether 5-HT manipulation, through a tryptophan (TRP) depletion by diet in Wistar and Lister Hooded rats, modulates compulsive drinking in schedule-induced polydipsia (SIP) and locomotor activity in the open-field test. The levels of dopamine, noradrenaline, serotonin and its metabolite were......-depleted HD Wistar rats, while the LD Wistar and the Lister Hooded rats did not exhibit differences in SIP. In contrast, the TRP-depleted Lister Hooded rats increased locomotor activity compared to the non-depleted rats, while no differences were found in the Wistar rats. Serotonin 2A receptor binding...

  12. Dysbiosis of the Vaginal Microbiota and Higher Vaginal Kynurenine/Tryptophan Ratio Reveals an Association with Chlamydia trachomatis Genital Infections

    Directory of Open Access Journals (Sweden)

    Noa Ziklo

    2018-01-01

    Full Text Available The natural course of Chlamydia trachomatis urogenital tract infections varies between individuals. While protective immunity can occur, some women can become reinfected, contributing to the development of severe pathology. While the reasons for these differences are unknown, an individual's response to induced interferon-γ (IFN-γ is suggested to be critical. IFN-γ induction of the enzyme indoleamine 2,3-dioxygenase, which depletes tryptophan, may be the key. One hypothesis suggests that indole-producing bacteria in the vaginal microbiota can provide a substrate for the Chlamydia to synthesize tryptophan, rescuing the Chlamydia from host IFN-γ attack. We studied a cohort of 25 women who were either, Chlamydia negative, Chlamydia positive with a single infection, or Chlamydia positive with repeated infection, to test our hypothesis. We characterized their vaginal microbiota, cytokine response, as well as their tryptophan, kynurenine and indole concentrations directly in vaginal secretions. We found that C. trachomatis urogenital tract infections either initial or repeat infections, were associated with elevated vaginal kynurenine/tryptophan ratios, primarily as a result of elevated kynurenine levels. In addition, vaginal microbiota of community state type (CST IV showed significantly lower vaginal tryptophan levels compared to CST I and III, which might be related to a higher abundance of indole producers found within this group. Furthermore, we found a higher abundance of indole producers in women who cleared their Chlamydia infection post antibiotic treatment. This study demonstrates for the first time in vivo, the association between high vaginal kynurenine/tryptophan ratios and C. trachomatis infections. In addition, tryptophan depletion was associated with vaginal microbiota of CST IV.

  13. Mapping Hfq-RNA interaction surfaces using tryptophan fluorescence quenching

    Science.gov (United States)

    Robinson, Kirsten E.; Orans, Jillian; Kovach, Alexander R.; Link, Todd M.; Brennan, Richard G.

    2014-01-01

    Hfq is a posttranscriptional riboregulator and RNA chaperone that binds small RNAs and target mRNAs to effect their annealing and message-specific regulation in response to environmental stressors. Structures of Hfq-RNA complexes indicate that U-rich sequences prefer the proximal face and A-rich sequences the distal face; however, the Hfq-binding sites of most RNAs are unknown. Here, we present an Hfq-RNA mapping approach that uses single tryptophan-substituted Hfq proteins, all of which retain the wild-type Hfq structure, and tryptophan fluorescence quenching (TFQ) by proximal RNA binding. TFQ properly identified the respective distal and proximal binding of A15 and U6 RNA to Gram-negative Escherichia coli (Ec) Hfq and the distal face binding of (AA)3A, (AU)3A and (AC)3A to Gram-positive Staphylococcus aureus (Sa) Hfq. The inability of (GU)3G to bind the distal face of Sa Hfq reveals the (R-L)n binding motif is a more restrictive (A-L)n binding motif. Remarkably Hfq from Gram-positive Listeria monocytogenes (Lm) binds (GU)3G on its proximal face. TFQ experiments also revealed the Ec Hfq (A-R-N)n distal face-binding motif should be redefined as an (A-A-N)n binding motif. TFQ data also demonstrated that the 5′-untranslated region of hfq mRNA binds both the proximal and distal faces of Ec Hfq and the unstructured C-terminus. PMID:24288369

  14. Confirmation of antibodies against L-tryptophan-like epitope in ...

    African Journals Online (AJOL)

    Confirmation of antibodies against L-tryptophan-like epitope in human African trypanosomosis serological diagnostic. ... number of patients in Congo. A diagnostic test based on this synthetic epitope, especially in combination with other tests, might improve the HAT diagnostic test in field conditions. Key words: Tryptophan ...

  15. Comparison between total lung capacity and residual volume values obtained by pletysmography and single breath methods with methane

    Directory of Open Access Journals (Sweden)

    Ricardo Marques Dias

    2006-11-01

    Full Text Available We analyzed pulmonary function tests of twenty asthmatic patients from Gaffrée e Guinle University Hospital, classified according to Brazilian Guidelines for Asthma (2002, similar to GINA, into mild persistent or moderate (9 or severe (11 asthma. We obtained parameters from spirometry, plethysmograph(PL and single breath technique for diffusion capacity (SB, with methane. Total lung capacity and residual volume were called TLCPL and RVPL when measured by pletysmography and TLCSB and RVSB when determined by single breath test. There were 13 women and 7 men with mean age of 47.6 years. The pulmonary dysfunction degree to FEV1/FVC was 58.8% with CI95=53.9 to 63.6. The mean values in litres for TLCPL (5.94 and RVPL (2.55 were significantly higher than for TLCSB (4.73 and RVSB (1.66. Multiple regression equations were determined for TLCPL e RVPL using only single breath values, TLCSB or RVSB, and spirographic parameters, with significant regression coefficients. However, the inclusion of spirometric parameters, except for FVC, did not improve the predicted capacity for the equations. Considering only the TLCSB, r2=0.79, the equation is: TLCPL=(TLCSB*1.025+1.088, with EPE=0.64. The regression for RVPL, r2=0.23, is: RVPL=(RVSB*0.9268+1.012. The results obtained after bronchodilation with 400 mcg of salbutamol did not improve the regression. We concluded that the SB technique did not obtain the same results as pletysmography for TLC and RV, but for TLC this difference can be predicted. Resumo: Foram analisados exames de função pulmonar de 20 asmáticos, em acompanhamento no HU Gaffrée Guinle, classificados, segundo o Consenso Brasileiro (2002, em asma leve persistente ou moderada (9 e grave (11. Foram obtidos os valores dos parâmetros da espirografia, da pletismografia e da técnica de respiração única, com metano, para a medida da difusão pulmonar (DLco. Assim, a capacidade pulmonar total e o volume residual, quando

  16. Tryptophan fluorescence in the Bacillus subtilis phototropin-related protein YtvA as a marker of interdomain interaction.

    Science.gov (United States)

    Losi, Aba; Ternelli, Elena; Gärtner, Wolfgang

    2004-01-01

    The Bacillus subtilis protein YtvA, related to plant phototropins (phot), binds flavin mononucleotide (FMN) within the N-terminal light, oxygen and voltage (LOV) domain. The blue light-triggered photocycle of YtvA and phot involves the reversible formation of a covalent photoadduct between FMN and a cysteine (cys) residue. YtvA contains a single tryptophan, W103, localized on the LOV domain and conserved in all phot-LOV domains. In this study, we show that the fluorescence parameters of W103 in YtvA-LOV are markedly different from those observed in the full-length YtvA. The fluorescence quantum yields are ca 0.03 and 0.08, respectively. In YtvA-LOV, the maximum is redshifted (ca 345 vs 335 nm) and the average fluorescence lifetime shorter (2.7 vs 4.7 ns). These data indicate that W103 is located in a site of tight contact between the two domains of YtvA. In the FMN-cys adduct, selective excitation of W103 at 295 nm results in minimal changes of the fluorescence parameters with respect to the dark state. On 280 nm excitation, however, there is a detectable decrease in the fluorescence emitted from tyrosines, with concomitant increase in W103 fluorescence. This effect is reversible in the dark and might arise from a light-regulated energy transfer process from a yet unidentified tyrosine to W103.

  17. Stochastic thermodynamics of a chemical nanomachine: The channeling enzyme tryptophan synthase.

    Science.gov (United States)

    Loutchko, Dimitri; Eisbach, Maximilian; Mikhailov, Alexander S

    2017-01-14

    The enzyme tryptophan synthase is characterized by a complex pattern of allosteric interactions that regulate the catalytic activity of its two subunits and opening or closing of their ligand gates. As a single macromolecule, it implements 13 different reaction steps, with an intermediate product directly channeled from one subunit to another. Based on experimental data, a stochastic model for the operation of tryptophan synthase has been earlier constructed [D. Loutchko, D. Gonze, and A. S. Mikhailov, J. Phys. Chem. B 120, 2179 (2016)]. Here, this model is used to consider stochastic thermodynamics of such a chemical nanomachine. The Gibbs energy landscape of the internal molecular states is determined, the production of entropy and its flow within the enzyme are analyzed, and the information exchange between the subunits resulting from allosteric cross-regulations and channeling is discussed.

  18. Tryptophan levels, excessive exercise, and nutritional status in anorexia nervosa.

    Science.gov (United States)

    Favaro, A; Caregaro, L; Burlina, A B; Santonastaso, P

    2000-01-01

    It has been hypothesized that reduced dietary availability of tryptophan may be the cause of impaired serotonin activity in underweight anorexics. The study reported here evaluated the relationship between tryptophan availability in the blood and nutritional status in anorexia nervosa. The total amount of tryptophan and the ratio between tryptophan and other large neutral amino acids (TRP/LNAA) were assessed in a sample of 16 starving anorexic patients. Body weight and composition and energy intake were evaluated in all patients. All subjects also completed self-reported questionnaires such as the Hopkins Symptom Checklist and Eating Disorders Inventory (EDI). The TRP/LNAA ratio seems to be higher in patients with a more severe catabolic status. It is, in fact, significantly inversely correlated with body mass index, body fat, muscle mass, daily energy intake, and daily tryptophan intake. The TRP/LNAA ratio also correlates with growth hormone and the EDI drive for thinness. Patients who exercise excessively had significantly higher TRP/LNAA ratios. In starving anorexic patients, the TRP/LNAA ratio does not seem to be determined by the content of tryptophan in the diet, but it correlates with measures of catabolism. The relationship of the TRP/LNAA ratio to excessive exercise and starvation indicates the importance of further investigations exploring the role of tryptophan availability in maintaining anorexia nervosa.

  19. Single particle analysis of ice crystal residuals observed in orographic wave clouds over Scandinavia during INTACC experiment

    Directory of Open Access Journals (Sweden)

    A. C. Targino

    2006-01-01

    Full Text Available Individual ice crystal residual particles collected over Scandinavia during the INTACC (INTeraction of Aerosol and Cold Clouds experiment in October 1999 were analyzed by Scanning Electron Microscopy (SEM equipped with Energy-Dispersive X-ray Analysis (EDX. Samples were collected onboard the British Met Office Hercules C-130 aircraft using a Counterflow Virtual Impactor (CVI. This study is based on six samples collected in orographic clouds. The main aim of this study is to characterize cloud residual elemental composition in conditions affected by different airmasses. In total 609 particles larger than 0.1 μm diameter were analyzed and their elemental composition and morphology were determined. Thereafter a hierarchical cluster analysis was performed on the signal detected with SEM-EDX in order to identify the major particle classes and their abundance. A cluster containing mineral dust, represented by aluminosilicates, Fe-rich and Si-rich particles, was the dominating class of particles, accounting for about 57.5% of the particles analyzed, followed by low-Z particles, 23.3% (presumably organic material and sea salt (6.7%. Sulfur was detected often across all groups, indicating ageing and in-cloud processing of particles. A detailed inspection of samples individually unveiled a relationship between ice crystal residual composition and airmass origin. Cloud residual samples from clean airmasses (that is, trajectories confined to the Atlantic and Arctic Oceans and/or with source altitude in the free troposphere were dominated primarily by low-Z and sea salt particles, while continentally-influenced airmasses (with trajectories that originated or traveled over continental areas and with source altitude in the continental boundary layer contained mainly mineral dust residuals. Comparison of residual composition for similar cloud ambient temperatures around –27°C revealed that supercooled clouds are more likely to persist in conditions where

  20. Exploring the mechanism of tryptophan 2,3-dioxygenase

    Science.gov (United States)

    Thackray, Sarah J.; Mowat, Christopher G.; Chapman, Stephen K.

    2008-01-01

    The haem proteins TDO (tryptophan 2,3-dioxygenase) and IDO (indoleamine 2,3-dioxygenase) are specific and powerful oxidation catalysts that insert one molecule of dioxygen into L-tryptophan in the first and rate-limiting step in the kynurenine pathway. Recent crystallographic and biochemical analyses of TDO and IDO have greatly aided our understanding of the mechanisms employed by these enzymes in the binding and activation of dioxygen and tryptophan. In the present paper, we briefly discuss the function, structure and possible catalytic mechanism of these enzymes. PMID:19021508

  1. Leaching of APC residues from secondary Pb metallurgy using single extraction tests: the mineralogical and the geochemical approach.

    Science.gov (United States)

    Ettler, Vojtech; Mihaljevic, Martin; Sebek, Ondrej; Strnad, Ladislav

    2005-05-20

    Two air-pollution-control (APC) residues--one from flue gas cooling with alkaline water and one from deionized water cooling--from secondary lead metallurgy were submitted to two different standardized short-term leaching protocols: US EPA toxicity characteristic leaching procedure (TCLP) and static leaching according to Czech/European norm EN 12457-2. The experimental procedure was coupled with detailed mineralogical investigation of the solid material (SEM, XRPD) and speciation-solubility calculations using the PHREEQC-2 geochemical code. Both types of residues were considered as hazardous materials exhibiting substantial leaching of Pb (up to 7130 mg/l) and other inorganic contaminants. However, the APC residue produced by flue gas cooling with alkaline water (sample B) exhibits more favourable leaching and environmental characteristics than that produced by simple deionised water cooling (sample A). At pH 6, phosgenite (PbCl2.PbCO3) became the dominant secondary phase. The results are consistent with the mineralogical and geochemical studies focused on acidic forest soils highly polluted by smelter emissions, where anglesite, as a unique Pb-bearing phase, has been detected. From the technological point of view, the mixing of APC residue with alkaline water, followed by an increase in the suspension pH and equilibration with atmospheric CO2, may be used to ensure the precipitation of less soluble Pb carbonates, which are more easily recycled in the Pb recovery process in the metallurgical plant.

  2. High stability and biological activity of the copper(II) complexes of alloferon 1 analogues containing tryptophan.

    Science.gov (United States)

    Kadej, Agnieszka; Kuczer, Mariola; Czarniewska, Elżbieta; Urbański, Arkadiusz; Rosiński, Grzegorz; Kowalik-Jankowska, Teresa

    2016-10-01

    Copper(II) complex formation processes between the alloferon 1 (Allo1) (HGVSGHGQHGVHG) analogues where the tryptophan residue is introducing in the place His residue H1W, H6W, H9W and H12W have been studied by potentiometric, UV-visible, CD and EPR spectroscopic, and MS methods. For all analogues of alloferon 1 complex speciation have been obtained for a 1:1 metal-to-ligand molar ratio and 2:1 of H1W because of precipitation at higher (2:1, 3:1 and 4:1) ratios. At physiological pH7.4 and a 1:1 metal-to-ligand molar ratio the tryptophan analogues of alloferon 1 form the CuH -1 L and/or CuH -2 L complexes with the 4N binding mode. The introduction of tryptophan in place of histidine residues changes the distribution diagram of the complexes formed with the change of pH and their stability constants compared to the respective substituted alanine analogues of alloferon 1. The CuH -1 L, CuH -2 L and CuH -3 L complexes of the tryptophan analogues are more stable from 1 to 5 log units in comparison to those of the alanine analogues. This stabilization of the complexes may result from cation(Cu(II))-π and indole/imidazole ring interactions. The induction of apoptosis in vivo, in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH7.4 was studied. The biological results show that copper(II) ions in vivo did not cause any apparent apoptotic features. The most active were the H12W peptide and Cu(II)-H12W complex formed at pH7.4. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Cyclopiazonic acid biosynthesis in Aspergillus sp.: characterization of a reductase-like R* domain in cyclopiazonate synthetase that forms and releases cyclo-acetoacetyl-L-tryptophan.

    Science.gov (United States)

    Liu, Xinyu; Walsh, Christopher T

    2009-09-15

    The fungal neurotoxin alpha-cyclopiazonic acid (CPA), a nanomolar inhibitor of Ca2+-ATPase, has a pentacyclic indole tetramic acid scaffold that arises from one molecule of tryptophan, acetyl-CoA, malonyl-CoA, and dimethylallyl pyrophosphate by consecutive action of three enzymes, CpaS, CpaD, and CpaO. CpaS is a hybrid, two module polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) that makes and releases cyclo-acetoacetyl-L-tryptophan (cAATrp), the tetramic acid that serves as substrate for subsequent prenylation and oxidative cyclization to the five ring CPA scaffold. The NRPS module in CpaS has a predicted four-domain organization of condensation, adenylation, thiolation, and reductase* (C-A-T-R*), where R* lacks the critical Ser-Tyr-Lys catalytic triad of the short chain dehydrogenase/reductase (SDR) superfamily. By heterologous overproduction in Escherichia coli of the 56 kDa Aspergillus flavus CpaS TR* didomain and the single T and R* domains, we demonstrate that CpaS catalyzes a Dieckmann-type cyclization on the N-acetoacetyl-Trp intermediate bound in thioester linkage to the phosphopantetheinyl arm of the T domain to form and release cAATrp. This occurs without any participation of NAD(P)H, so R* does not function as a canonical SDR family member. Use of the T and R* domains in in trans assays enabled multiple turnovers and evaluation of specific mutants. Mutation of the D3803 residue in the R* domain, conserved in other fungal tetramate synthetases, abolished activity both in in trans and in cis (TR*) activity assays. It is likely that cyclization of beta-ketoacylaminoacyl-S-pantetheinyl intermediates to released tetramates represents a default cyclization/release route for redox-incompetent R* domains embedded in NRPS assembly lines.

  4. Development of Bacillus subtilis mutants to produce tryptophan in pigs

    DEFF Research Database (Denmark)

    Bjerre, Karin; Cantor, Mette D.; Nørgaard, Jan Værum

    2017-01-01

    Objectives To generate tryptophan-overproducing Bacillus subtilis strains for in situ use in pigs, to reduce the feed cost for farmers and nitrogen pollution. Results A novel concept has been investigated—to generate B. subtilis strains able to produce tryptophan (Trp) in situ in pigs. Mutagenesis......-excreting B. subtilis strains were obtained with UV-mutagenesis and analogue selection and can be used in animal feed applications....

  5. Substitution of Active Site Tyrosines with Tryptophan Alters the Free Energy for Nucleotide Flipping by Human Alkyladenine DNA Glycosylase†

    Science.gov (United States)

    Hendershot, Jenna M.; Wolfe, Abigail E.; O'Brien, Patrick J.

    2011-01-01

    Human alkyladenine DNA glycosylase (AAG) locates and excises a wide variety of structurally diverse alkylated and oxidized purine lesions from DNA to initiate the base excision repair pathway. Recognition of a base lesion requires flipping of the damaged nucleotide into a relatively open active site pocket between two conserved tyrosine residues, Y127 and Y159. We have mutated each of these amino acids to tryptophan and measured the kinetic effects on the nucleotide flipping and base excision steps. The Y127W and Y159W mutant proteins have robust glycosylase activity toward DNA containing 1,N6-ethenoadenine (εA), within 4-fold of that of the wildtype enzyme, raising the possibility that tryptophan fluorescence could be used to probe the DNA binding and nucleotide flipping steps. Stopped-flow fluorescence was used to compare the time-dependent changes in tryptophan fluorescence and εA fluorescence. For both mutants, the tryptophan fluorescence exhibited two-step binding with essentially identical rate constants as were observed for the εA fluorescence changes. These results provide evidence that AAG forms an initial recognition complex in which the active site pocket is perturbed and the stacking of the damaged base is disrupted. Upon complete nucleotide flipping, there is further quenching of the tryptophan fluorescence with coincident quenching of the εA fluorescence. Although these mutations do not have large effects on the rate constant for excision of εA, there are dramatic effects on the rate constants for nucleotide flipping that result in 40 to 100-fold decreases in the flipping equilibrium relative to wildtype. Most of this effect is due to an increased rate of unflipping, but surprisingly the Y159W mutation causes a 5-fold increase in the rate constant for flipping. The large effect on the equilibrium for nucleotide flipping explains the greater deleterious effects that these mutations have on the glycosylase activity toward base lesions that are in

  6. A single arginine residue is required for the interaction of the electron transferring flavoprotein (ETF) with three of its dehydrogenase partners.

    Science.gov (United States)

    Parker, Antony R

    2003-12-01

    The interaction of several dehydrogenases with the electron transferring flavoprotein (ETF) is a crucial step required for the successful transfer of electrons into the electron transport chain. The exact determinants regarding the interaction of ETF with its dehydrogenase partners are still unknown. Chemical modification of ETF with arginine-specific reagents resulted in the loss, to varying degrees, of activity with medium chain acyl-coenzyme A dehydrogenase (MCAD). The kinetic profiles showed the inactivations followed pseudo-first-order kinetics for all reagents used. For activity with MCAD, maximum inactivation of ETF was accomplished by 2,3-butanedione (4% residual activity after 120 min) and it was shown that modification of one arginine residue was responsible for the inactivation. Almost 100% restoration of this ETF activity was achieved upon incubation with free arginine. However, the same 2,3-butanedione modified ETF only possessed decreased activity with dimethylglycine-(DMGDH, 44%) and sarcosine- (SDH, 27%) dehydrogenases unlike the abolition with MCAD. Full protection of ETF from arginine modification by 2,3-butanedione was achieved using substrate-protected DMGDH, MCAD and SDH respectively. Cross-protection studies of ETF with the three dehydrogenases implied use of the same single arginine residue in the binding of all three dehydrogenases. These results lead us to conclude that this single arginine residue is essential in the binding of the ETF to MCAD, but only contributes partially to the binding of ETF to SDH and DMGDH and thus, the determinants of the dehydrogenase binding sites overlap but are not identical.

  7. Characterization of f-actin tryptophan phosphorescence in the presence and absence of tryptophan-free myosin motor domain.

    Science.gov (United States)

    Bódis, Emöke; Strambini, Giovanni B; Gonnelli, Margherita; Málnási-Csizmadia, András; Somogyi, Béla

    2004-08-01

    The effect of binding the Trp-free motor domain mutant of Dictyostelium discoideum, rabbit skeletal muscle myosin S1, and tropomyosin on the dynamics and conformation of actin filaments was characterized by an analysis of steady-state tryptophan phosphorescence spectra and phosphorescence decay kinetics over a temperature range of 140-293 K. The binding of the Trp-free motor domain mutant of D. discoideum to actin caused red shifts in the phosphorescence spectrum of two internal Trp residues of actin and affected the intrinsic lifetime of each emitter, decreasing by roughly twofold the short phosphorescence lifetime components (tau(1) and tau(2)) and increasing by approximately 20% the longest component (tau(3)). The alteration of actin phosphorescence by the motor protein suggests that i), structural changes occur deep down in the core of actin and that ii), subtle changes in conformation appear also on the surface but in regions distant from the motor domain binding site. When actin formed complexes with skeletal S1, an extra phosphorescence lifetime component appeared (tau(4), twice as long as tau(3)) in the phosphorescence decay that is absent in the isolated proteins. The lack of this extra component in the analogous actin-Trp-free motor domain mutant of D. discoideum complex suggests that it should be assigned to Trps in S1 that in the complex attain a more compact local structure. Our data indicated that the binding of tropomyosin to actin filaments had no effect on the structure or flexibility of actin observable by this technique.

  8. Errors in Computing the Normalized Protein Catabolic Rate due to Use of Single-pool Urea Kinetic Modeling or to Omission of the Residual Kidney Urea Clearance.

    Science.gov (United States)

    Daugirdas, John T

    2017-07-01

    The protein catabolic rate normalized to body size (PCRn) often is computed in dialysis units to obtain information about protein ingestion. However, errors can manifest when inappropriate modeling methods are used. We used a variable volume 2-pool urea kinetic model to examine the percent errors in PCRn due to use of a 1-pool urea kinetic model or after omission of residual urea clearance (Kru). When a single-pool model was used, 2 sources of errors were identified. The first, dependent on the ratio of dialyzer urea clearance to urea distribution volume (K/V), resulted in a 7% inflation of the PCRn when K/V was in the range of 6 mL/min per L. A second, larger error appeared when Kt/V values were below 1.0 and was related to underestimation of urea distribution volume (due to overestimation of effective clearance) by the single-pool model. A previously reported prediction equation for PCRn was valid, but data suggest that it should be modified using 2-pool eKt/V and V coefficients instead of single-pool values. A third source of error, this one unrelated to use of a single-pool model, namely omission of Kru, was shown to result in an underestimation of PCRn, such that each ml/minute Kru per 35 L of V caused a 5.6% underestimate in PCRn. Marked overestimation of PCRn can result due to inappropriate use of a single-pool urea kinetic model, particularly when Kt/V <1.0 (as in short daily dialysis), or after omission of residual native kidney clearance. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  9. A single acidic residue can guide binding site selection but does not govern QacR cationic-drug affinity.

    Directory of Open Access Journals (Sweden)

    Kate M Peters

    Full Text Available Structures of the multidrug-binding repressor protein QacR with monovalent and bivalent cationic drugs revealed that the carboxylate side-chains of E90 and E120 were proximal to the positively charged nitrogens of the ligands ethidium, malachite green and rhodamine 6G, and therefore may contribute to drug neutralization and binding affinity. Here, we report structural, biochemical and in vivo effects of substituting these glutamate residues. Unexpectedly, substitutions had little impact on ligand affinity or in vivo induction capabilities. Structures of QacR(E90Q and QacR(E120Q with ethidium or malachite green took similar global conformations that differed significantly from all previously described QacR-drug complexes but still prohibited binding to cognate DNA. Strikingly, the QacR(E90Q-rhodamine 6G complex revealed two mutually exclusive rhodamine 6G binding sites. Despite multiple structural changes, all drug binding was essentially isoenergetic. Thus, these data strongly suggest that rather than contributing significantly to ligand binding affinity, the role of acidic residues lining the QacR multidrug-binding pocket is primarily to attract and guide cationic drugs to the "best available" positions within the pocket that elicit QacR induction.

  10. Exchanging a single amino acid residue generates or weakens a +2 cellooligosaccharide binding subsite in rice β-glucosidases.

    Science.gov (United States)

    Sansenya, Sompong; Maneesan, Janjira; Cairns, James R Ketudat

    2012-04-01

    Os3BGlu6, Os3BGlu7, and Os4BGlu12 are rice glycoside hydrolase family 1 β-glucosidases, the structures of which have been solved by X-ray crystallography. In complex structures, Os3BGlu7 residue Asn245 hydrogen bonds to the second sugar in the +1 subsite for laminaribiose and the third sugar in the +2 subsite for cellotetraose and cellopentaose. The corresponding Os3BGlu6 residue, Met251, appears to block the binding of cellooligosaccharides at the +2 subsite, whereas His252 in this position in Os4BGlu12 could hydrogen bond to oligosaccharides. Mutation of Os3BGlu6 Met251 to Asn resulted in a 15-fold increased k(cat)/K(m) value for hydrolysis of laminaribiose compared to wild type Os3BGlu6 and 9 to 24-fold increases for cellooligosaccharides with degrees of polymerization (DP) of 2-5. On the other hand, mutation of Os3BGlu7 Asn245 to Met decreased the k(cat)/K(m) of hydrolysis by 6.5-fold for laminaribiose and 17 to 30-fold for cellooligosaccharides with DP >2, while mutation of Os4BGlu12 His252 to Met decreased the corresponding k(cat)/K(m) values 2 to 6-fold. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Kynurenine pathway in psychosis: evidence of increased tryptophan degradation.

    LENUS (Irish Health Repository)

    Barry, Sandra

    2009-05-01

    The kynurenine pathway of tryptophan degradation may serve to integrate disparate abnormalities heretofore identified in research aiming to elucidate the complex aetiopathogenesis of psychotic disorders. Post-mortem brain tissue studies have reported elevated kynurenine and kynurenic acid in the frontal cortex and upregulation of the first step of the pathway in the anterior cingulate cortex of individuals with schizophrenia. In this study, we examined kynurenine pathway activity by measuring tryptophan breakdown, a number of pathway metabolites and interferon gamma (IFN-gamma), which is the preferential activator of the first-step enzyme, indoleamine dioxygenase (IDO), in the plasma of patients with major psychotic disorder. Plasma tryptophan, kynurenine pathway metabolites were measured using high-performance liquid chromatography (HPLC) in 34 patients with a diagnosis on the psychotic spectrum (schizophrenia or schizoaffective disorder) and in 36 healthy control subjects. IFN-gamma was measured using enzyme-linked immunosorbent assay (ELISA). The mean tryptophan breakdown index (kynurenine\\/tryptophan) was significantly higher in the patient group compared with controls (P < 0.05). IFN-gamma measures did not differ between groups (P = 0.23). No relationship was found between measures of psychopathology, symptom severity and activity in the first step in the pathway. A modest correlation was established between the tryptophan breakdown index and illness duration. These results provide evidence for kynurenine pathway upregulation, specifically involving the first enzymatic step, in patients with major psychotic disorder. Increased tryptophan degradation in psychoses may have potential consequences for the treatment of these disorders by informing the development of novel therapeutic compounds.

  12. Tryptophan metabolism in breast cancers: molecular imaging and immunohistochemistry studies

    International Nuclear Information System (INIS)

    Juhász, Csaba; Nahleh, Zeina; Zitron, Ian; Chugani, Diane C.; Janabi, Majid Z.; Bandyopadhyay, Sudeshna; Ali-Fehmi, Rouba; Mangner, Thomas J.; Chakraborty, Pulak K.; Mittal, Sandeep; Muzik, Otto

    2012-01-01

    Introduction: Tryptophan oxidation via the kynurenine pathway is an important mechanism of tumoral immunoresistance. Increased tryptophan metabolism via the serotonin pathway has been linked to malignant progression in breast cancer. In this study, we combined quantitative positron emission tomography (PET) with tumor immunohistochemistry to analyze tryptophan transport and metabolism in breast cancer. Methods: Dynamic α-[ 11 C]methyl-L-tryptophan (AMT) PET was performed in nine women with stage II–IV breast cancer. PET tracer kinetic modeling was performed in all tumors. Expression of L-type amino acid transporter 1 (LAT1), indoleamine 2,3-dioxygenase (IDO; the initial and rate-limiting enzyme of the kynurenine pathway) and tryptophan hydroxylase 1 (TPH1; the initial enzyme of the serotonin pathway) was assessed by immunostaining of resected tumor specimens. Results: Tumor AMT uptake peaked at 5–20 min postinjection in seven tumors; the other two cases showed protracted tracer accumulation. Tumor standardized uptake values (SUVs) varied widely (2.6–9.8) and showed a strong positive correlation with volume of distribution values derived from kinetic analysis (P < .01). Invasive ductal carcinomas (n = 6) showed particularly high AMT SUVs (range, 4.7–9.8). Moderate to strong immunostaining for LAT1, IDO and TPH1 was detected in most tumor cells. Conclusions: Breast cancers show differential tryptophan kinetics on dynamic PET. SUVs measured 5–20 min postinjection reflect reasonably the tracer's volume of distribution. Further studies are warranted to determine if in vivo AMT accumulation in these tumors is related to tryptophan metabolism via the kynurenine and serotonin pathways.

  13. Tryptophan metabolism, disposition and utilization in pregnancy.

    Science.gov (United States)

    Badawy, Abdulla A-B

    2015-09-17

    Tryptophan (Trp) requirements in pregnancy are several-fold: (1) the need for increased protein synthesis by mother and for fetal growth and development; (2) serotonin (5-HT) for signalling pathways; (3) kynurenic acid (KA) for neuronal protection; (4) quinolinic acid (QA) for NAD(+) synthesis (5) other kynurenines (Ks) for suppressing fetal rejection. These goals could not be achieved if maternal plasma [Trp] is depleted. Although plasma total (free + albumin-bound) Trp is decreased in pregnancy, free Trp is elevated. The above requirements are best expressed in terms of a Trp utilization concept. Briefly, Trp is utilized as follows: (1) In early and mid-pregnancy, emphasis is on increased maternal Trp availability to meet the demand for protein synthesis and fetal development, most probably mediated by maternal liver Trp 2,3-dioxygenase (TDO) inhibition by progesterone and oestrogens. (2) In mid- and late pregnancy, Trp availability is maintained and enhanced by the release of albumin-bound Trp by albumin depletion and non-esterified fatty acid (NEFA) elevation, leading to increased flux of Trp down the K pathway to elevate immunosuppressive Ks. An excessive release of free Trp could undermine pregnancy by abolishing T-cell suppression by Ks. Detailed assessment of parameters of Trp metabolism and disposition and related measures (free and total Trp, albumin, NEFA, K and its metabolites and pro- and anti-inflammatory cytokines in maternal blood and, where appropriate, placental and fetal material) in normal and abnormal pregnancies may establish missing gaps in our knowledge of the Trp status in pregnancy and help identify appropriate intervention strategies. © 2015 Authors.

  14. Notice of Violation of IEEE Publication PrinciplesJoint Redundant Residue Number Systems and Module Isolation for Mitigating Single Event Multiple Bit Upsets in Datapath

    Science.gov (United States)

    Li, Lei; Hu, Jianhao

    2010-12-01

    Notice of Violation of IEEE Publication Principles"Joint Redundant Residue Number Systems and Module Isolation for Mitigating Single Event Multiple Bit Upsets in Datapath"by Lei Li and Jianhao Hu,in the IEEE Transactions on Nuclear Science, vol.57, no.6, Dec. 2010, pp. 3779-3786After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles.This paper contains substantial duplication of original text from the paper cited below. The original text was copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission.Due to the nature of this violation, reasonable effort should be made to remove all past references to this paper, and future references should be made to the following articles:"Multiple Error Detection and Correction Based on Redundant Residue Number Systems"by Vik Tor Goh and M.U. Siddiqi,in the IEEE Transactions on Communications, vol.56, no.3, March 2008, pp.325-330"A Coding Theory Approach to Error Control in Redundant Residue Number Systems. I: Theory and Single Error Correction"by H. Krishna, K-Y. Lin, and J-D. Sun, in the IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, vol.39, no.1, Jan 1992, pp.8-17In this paper, we propose a joint scheme which combines redundant residue number systems (RRNS) with module isolation (MI) for mitigating single event multiple bit upsets (SEMBUs) in datapath. The proposed hardening scheme employs redundant residues to improve the fault tolerance for datapath and module spacings to guarantee that SEMBUs caused by charge sharing do not propagate among the operation channels of different moduli. The features of RRNS, such as independence, parallel and error correction, are exploited to establish the radiation hardening architecture for the datapath in radiation environments. In the proposed

  15. Nanosecond dynamics of influenza A/M2TM and an amantadine resistant mutant probed by time-dependent red shifts of a native tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, Vikas [Center for Advanced Biotechnology and Medicine, Robert Wood Johnson Medical School – UMDNJ, Piscataway, NJ 08854 (United States); Department of Biochemistry, Robert Wood Johnson Medical School – UMDNJ, Piscataway, NJ 08854 (United States); Cristian, Lidia [Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059 (United States); Toptygin, Dmitri; Brand, Ludwig [Department of Biology, Johns Hopkins University, Baltimore, MD 21218 (United States); DeGrado, William F., E-mail: William.Degrado@ucsf.edu [Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158 (United States)

    2013-08-30

    Highlights: ► Examined nanosecond dynamics of essential tryptophan residue of M2 proton channel. ► Channel blocking drugs restrict the ability of M2 to stabilize charge. ► Dielectric relaxation of M2 consistent with molecular dynamics simulation studies. - Abstract: Proteins involved in functions such as electron transfer or ion transport must be capable of stabilizing transient charged species on time scales ranging from picoseconds to microseconds. We study the influenza A M2 proton channel, containing a tryptophan residue that serves as an essential part of the proton conduction pathway. We induce a transition dipole in tryptophan by photoexcitation, and then probe the dielectric stabilization of its excited state. The magnitude of the stabilization over this time regime was larger than that generally found for tryptophan in membrane or protein environments. M2 achieves a water-like stabilization over a 25 ns time scale, slower than that of bulk water, but sufficiently rapid to contribute to stabilization of charge as protons diffuse through the channel. These measurements should stimulate future MD studies to clarify the role of sidechain versus non-bulk water in defining the process of relaxation.

  16. Comparison of sample digestion techniques for the determination of trace and residual catalyst metal content in single-wall carbon nanotubes by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Patricia, E-mail: patricia.grinberg@nrc.ca [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Sturgeon, Ralph E. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Diehl, Liange de O.; Bizzi, Cezar A. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil); Flores, Erico M.M. [Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil)

    2015-03-01

    A single-wall carbon nanotube material produced by laser ablation of renewable biochar in the presence of Ni and Co catalyst was characterized for residual catalyst (Co and Ni) as well as trace metal impurity content (Fe, Mo, Cr, Pb and Hg) by isotope dilution ICP-MS following sample digestion. Several matrix destruction procedures were evaluated, including a multi-step microwave-assisted acid digestion, dry ashing at 450 °C and microwave-induced combustion with oxygen. Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements. Although laborious to execute, the multi-step microwave-assisted acid digestion proved to be most reliable for recovery of the majority of the analytes, although content of Cr remained biased low for each approach, likely due to its presence as refractory carbide. - Highlights: • Determination of trace and residual catalyst metal content in Single-Wall Carbon Nanotubes by Inductively Coupled Plasma Mass Spectrometry. • Comparative study of digestion methodology combined with high precision isotope dilution ICP-MS for quantitation of elements of toxicologic relevance. • Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements.

  17. Involvement of tryptophan hydroxylase 2 gene polymorphisms in susceptibility to tic disorder in Chinese Han population

    OpenAIRE

    Zheng, Ping; Li, Erzhen; Wang, Jianhua; Cui, Xiaodai; Wang, Liwen

    2013-01-01

    Abstract Background Tryptophan hydroxylase-2 (TPH2) is a potential candidate gene for screening tic disorder (TD). Methods A case–control study was performed to examine the association between the TPH2 gene and TD. The Sequenom® Mass ARRAY iPLEX GOLD System was used to genotype two single nucleotide polymorphisms (SNPs) of the TPH2 gene in 149 TD children and in 125 normal controls. Results For rs4565946, individuals with the TT genotype showed a significantly higher risk of TD than those wit...

  18. Mechanistic deductions from multiple kinetic and solvent deuterium isotope effects and pH studies of pyridoxal phosphate dependent carbon-carbon lyases: escherichia coli tryptophan indole-lyase

    International Nuclear Information System (INIS)

    Kiick, D.M.; Phillips, R.S.

    1988-01-01

    Analysis of the pH dependence of the kinetic parameters and competitive inhibitor Ki values for tryptophan indole-lyase suggests two enzymic groups must be unprotonated in order to facilitate binding and catalysis of tryptophan. The V/K for tryptophan and the pKi for oxindolyl-L-alanine, a putative transition state analogue and competitive inhibitor, decrease below two pK values of 7.6 and 6.0, while the Ki for L-alanine, also a competitive inhibitor, is 3300-fold larger (20 mM) than that for oxindolyl-L-alanine and increases below a single pK of 7.6. A single pK of 7.6 is also observed in the V/K profile for the alternate substrate, S-methyl-L-cysteine. Therefore, the enzymic group with a pK of 7.6 is responsible for proton abstraction at the 2-position of tryptophan, while the enzymic group with a pK of 6.0 interacts with the indole portion of tryptophan and probably catalyzes formation of the indolenine tautomer of tryptophan (in concert with proton transfer to C-3 of indole from the group with pK 7.6) to facilitate carbon-carbon bond cleavage and elimination of indole. The pH variation of the primary deuterium isotope effects for proton abstraction at the 2-position of tryptophan (DV = 2.5 and D(V/Ktrp) = 2.8) are pH independent, while the Vmax for tryptophan or S-methyl-L-cysteine is the same and also pH independent. Thus, substrates bind only to the correctly protonated form of the enzyme. Further, tryptophan is not sticky, and the pK values observed in both V/K profiles are the correct ones

  19. Single-particle characterization of ice-nucleating particles and ice particles residuals sampled by three different techniques

    Science.gov (United States)

    Kandler, Konrad; Worringen, Annette; Benker, Nathalie; Dirsch, Thomas; Mertes, Stephan; Schenk, Ludwig; Kästner, Udo; Frank, Fabian; Nillius, Björn; Bundke, Ulrich; Rose, Diana; Curtius, Joachim; Kupiszewski, Piotr; Weingartner, Ernest; Vochezer, Paul; Schneider, Johannes; Schmidt, Susan; Weinbruch, Stephan; Ebert, Martin

    2015-04-01

    During January/February 2013, at the High Alpine Research Station Jungfraujoch a measurement campaign was carried out, which was centered on atmospheric ice-nucleating particles (INP) and ice particle residuals (IPR). Three different techniques for separation of INP and IPR from the non-ice-active particles are compared. The Ice Selective Inlet (ISI) and the Ice Counterflow Virtual Impactor (Ice-CVI) sample ice particles from mixed phase clouds and allow for the analysis of the residuals. The combination of the Fast Ice Nucleus Chamber (FINCH) and the Ice Nuclei Pumped Counterflow Virtual Impactor (IN-PCVI) provides ice-activating conditions to aerosol particles and extracts the activated INP for analysis. Collected particles were analyzed by scanning electron microscopy and energy-dispersive X-ray microanalysis to determine size, chemical composition and mixing state. All INP/IPR-separating techniques had considerable abundances (median 20 - 70 %) of instrumental contamination artifacts (ISI: Si-O spheres, probably calibration aerosol; Ice-CVI: Al-O particles; FINCH+IN-PCVI: steel particles). Also, potential sampling artifacts (e.g., pure soluble material) occurred with a median abundance of separated by all three techniques. Soot was a minor contributor. Lead was detected in less than 10 % of the particles, of which the majority were internal mixtures with other particle types. Sea-salt and sulfates were identified by all three methods as INP/IPR. Most samples showed a maximum of the INP/IPR size distribution at 400 nm geometric diameter. In a few cases, a second super-micron maximum was identified. Soot/carbonaceous material and metal oxides were present mainly in the submicron range. ISI and FINCH yielded silicates and Ca-rich particles mainly with diameters above 1 µm, while the Ice-CVI also separated many submicron IPR. As strictly parallel sampling could not be performed, a part of the discrepancies between the different techniques may result from

  20. Role of quaternary structure in muscle creatine kinase stability: tryptophan 210 is important for dimer cohesion.

    Science.gov (United States)

    Perraut, C; Clottes, E; Leydier, C; Vial, C; Marcillat, O

    1998-07-01

    A mutant of the dimeric rabbit muscle creatine kinase (MM-CK) in which tryptophan 210 was replaced has been studied to assess the role of this residue in dimer cohesion and the importance of the dimeric state for the native enzyme stability. Wild-type protein equilibrium unfolding induced by guanidine hydrochloride occurs through intermediate states with formation of a molten globule and a premolten globule. Unlike the wild-type enzyme, the mutant inactivates at lower denaturant concentration and the loss of enzymatic activity is accompanied by the dissociation of the dimer into two apparently compact monomers. However, the Stokes radius of the monomer increases with denaturant concentration as determined by size exclusion chromatography, indicating that, upon monomerization, the protein structure is destabilized. Binding of 8-anilinonaphthalene-1-sulfonate shows that the dissociated monomer exposes hydrophobic patches at its surface, suggesting that it could be a molten globule. At higher denaturant concentrations, both wild-type and mutant follow similar denaturation pathways with formation of a premolten globule around 1.5-M guanidine, indicating that tryptophan 210 does not contribute to a large extent to the monomer conformational stability, which may be ensured in the dimeric state through quaternary interactions.

  1. Charged residues in the H-NS linker drive DNA binding and gene silencing in single cells.

    Science.gov (United States)

    Gao, Yunfeng; Foo, Yong Hwee; Winardhi, Ricksen S; Tang, Qingnan; Yan, Jie; Kenney, Linda J

    2017-11-21

    Nucleoid-associated proteins (NAPs) facilitate chromosome organization in bacteria, but the precise mechanism remains elusive. H-NS is a NAP that also plays a major role in silencing pathogen genes. We used genetics, single-particle tracking in live cells, superresolution microscopy, atomic force microscopy, and molecular dynamics simulations to examine H-NS/DNA interactions in single cells. We discovered a role for the unstructured linker region connecting the N-terminal oligomerization and C-terminal DNA binding domains. In the present work we demonstrate that linker amino acids promote engagement with DNA. In the absence of linker contacts, H-NS binding is significantly reduced, although no change in chromosome compaction is observed. H-NS is not localized to two distinct foci; rather, it is scattered all around the nucleoid. The linker makes DNA contacts that are required for gene silencing, while chromosome compaction does not appear to be an important H-NS function.

  2. Chimeras Reveal a Single Lipid-Interface Residue that Controls MscL Channel Kinetics as well as Mechanosensitivity

    Directory of Open Access Journals (Sweden)

    Li-Min Yang

    2013-02-01

    Full Text Available MscL, the highly conserved bacterial mechanosensitive channel of large conductance, serves as an osmotic “emergency release valve,” is among the best-studied mechanosensors, and is a paradigm of how a channel senses and responds to membrane tension. Although all homologs tested thus far encode channel activity, many show functional differences. We tested Escherichia coli and Staphylococcus aureus chimeras and found that the periplasmic region of the protein, particularly E. coli I49 and the equivalent S. aureus F47 at the periplasmic lipid-aqueous interface of the first transmembrane domain, drastically influences both the open dwell time and the threshold of channel opening. One mutant shows a severe hysteresis, confirming the importance of this residue in determining the energy barriers for channel gating. We propose that this site acts similarly to a spring for a clasp knife, adjusting the resistance for obtaining and stabilizing an open or closed channel structure.

  3. Tryptophan circuit in fatigue: From blood to brain and cognition.

    Science.gov (United States)

    Yamashita, Masatoshi; Yamamoto, Takanobu

    2017-11-15

    Brain tryptophan and its neuroactive metabolites play key roles in central fatigue. However, previous brain function analysis targets may have included both glia and neurons together. Here, we clarified the fatigue-cognitive circuit of the central-peripheral linkage, including the role of glial-neuronal interaction in cognition. Using a rat model of central fatigue induced by chronic sleep disorder (CFSD), we isolated presynaptic terminals and oligodendrocytes. Results showed that compared to control group, presynaptic levels of tryptophan, kynurenine, and kynurenic acid, but not serotonin, in the CFSD group were higher in the hypothalamus and hippocampus. Moreover, CFSD group had higher oligodendrocytic levels of tryptophan, and impaired spatial cognitive memory accuracy and increased hyperactivity and impulsivity. These findings suggest that dynamic change in glial-neuronal interactions within the hypothalamus-hippocampal circuit causes central fatigue, and increased tryptophan-kynurenic acid pathway activity in this circuit causes reduced cognitive function. Additionally, CFSD group had 1.5 times higher plasma levels of tryptophan and kynurenine. Furthermore, in rats undergoing intraperitoneal administration of kynurenine (100mg/kg) versus vehicle, kynurenine-treated rats showed enhanced production of kynurenic acid in the hippocampus, with suppressed recall of retained spatial cognitive memory. The study revealed that uptake of periphery-derived kynurenine and tryptophan into the brain enhances kynurenic acid production in the brain, and the three factors produce amplification effect involved in the role of central-peripheral linkage in central fatigue, triggering cognitive dysfunction. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Single-particle characterization of ice-nucleating particles and ice particle residuals sampled by three different techniques

    Science.gov (United States)

    Worringen, A.; Kandler, K.; Benker, N.; Dirsch, T.; Mertes, S.; Schenk, L.; Kästner, U.; Frank, F.; Nillius, B.; Bundke, U.; Rose, D.; Curtius, J.; Kupiszewski, P.; Weingartner, E.; Vochezer, P.; Schneider, J.; Schmidt, S.; Weinbruch, S.; Ebert, M.

    2015-04-01

    In the present work, three different techniques to separate ice-nucleating particles (INPs) as well as ice particle residuals (IPRs) from non-ice-active particles are compared. The Ice Selective Inlet (ISI) and the Ice Counterflow Virtual Impactor (Ice-CVI) sample ice particles from mixed-phase clouds and allow after evaporation in the instrument for the analysis of the residuals. The Fast Ice Nucleus Chamber (FINCH) coupled with the Ice Nuclei Pumped Counterflow Virtual Impactor (IN-PCVI) provides ice-activating conditions to aerosol particles and extracts the activated particles for analysis. The instruments were run during a joint field campaign which took place in January and February 2013 at the High Alpine Research Station Jungfraujoch (Switzerland). INPs and IPRs were analyzed offline by scanning electron microscopy and energy-dispersive X-ray microanalysis to determine their size, chemical composition and mixing state. Online analysis of the size and chemical composition of INP activated in FINCH was performed by laser ablation mass spectrometry. With all three INP/IPR separation techniques high abundances (median 20-70%) of instrumental contamination artifacts were observed (ISI: Si-O spheres, probably calibration aerosol; Ice-CVI: Al-O particles; FINCH + IN-PCVI: steel particles). After removal of the instrumental contamination particles, silicates, Ca-rich particles, carbonaceous material and metal oxides were the major INP/IPR particle types obtained by all three techniques. In addition, considerable amounts (median abundance mostly a few percent) of soluble material (e.g., sea salt, sulfates) were observed. As these soluble particles are often not expected to act as INP/IPR, we consider them as potential measurement artifacts. Minor types of INP/IPR include soot and Pb-bearing particles. The Pb-bearing particles are mainly present as an internal mixture with other particle types. Most samples showed a maximum of the INP/IPR size distribution at 200

  5. Maternal dietary tryptophan deficiency alters cardiorespiratory control in rat pups.

    Science.gov (United States)

    Penatti, Eliana M; Barina, Alexis E; Raju, Sharat; Li, Aihua; Kinney, Hannah C; Commons, Kathryn G; Nattie, Eugene E

    2011-02-01

    Malnutrition during pregnancy adversely affects postnatal forebrain development; its effect upon brain stem development is less certain. To evaluate the role of tryptophan [critical for serotonin (5-HT) synthesis] on brain stem 5-HT and the development of cardiorespiratory function, we fed dams a diet ∼45% deficient in tryptophan during gestation and early postnatal life and studied cardiorespiratory variables in the developing pups. Deficient pups were of normal weight at postnatal day (P)5 but weighed less than control pups at P15 and P25 (P interactions between nutrition, brain stem physiology, and age that are potentially relevant to understanding 5-HT deficiency in the sudden infant death syndrome.

  6. Neurospora tryptophan synthase: N-terminal analysis and the sequence of the pyridoxal phosphate active site peptide

    International Nuclear Information System (INIS)

    Pratt, M.L.; Hsu, P.Y.; DeMoss, J.A.

    1986-01-01

    Tryptophan synthase (TS), which catalyzes the final step of tryptophan biosynthesis, is a multifunctional protein requiring pyridoxal phosphate (B6P) for two of its three distinct enzyme activities. TS from Neurospora has a blocked N-terminal, is a homodimer of 150 KDa and binds one mole of B6P per mole of subunit. The authors shown the N-terminal residue to be acyl-serine. The B6P-active site of holoenzyme was labelled by reduction of the B6P-Schiff base with [ 3 H]-NaBH 4 , and resulted in a proportionate loss of activity in the two B6P-requiring reactions. SDS-polyacrylamide gel electrophoresis of CNBr-generated peptides showed the labelled, active site peptide to be 6 KDa. The sequence of this peptide, purified to apparent homogeneity by a combination of C-18 reversed phase and TSK gel filtration HPLC is: gly-arg-pro-gly-gln-leu-his-lys-ala-glu-arg-leu-thr-glu-tyr-ala-gly-gly-ala-gln-ile-xxx-leu-lys-arg-glu-asp-leu-asn-his-xxx-gly-xxx-his-/sub ***/-ile-asn-asn-ala-leu. Although four residues (xxx, /sub ***/) are unidentified, this peptide is minimally 78% homologous with the corresponding peptide from yeast TS, in which residue (/sub ***/) is the lysine that binds B6P

  7. Cerebral 5-HT2A receptor binding, but not mGluR2, is increased in tryptophan hydroxylase 2 decrease-of-function mice

    DEFF Research Database (Denmark)

    Jørgensen, Christinna Vangsgaard; Jacobsen, Jacob P; Caron, Marc G

    2013-01-01

    Transgenic mice with a knock-in (KI) of a tryptophan hydroxylase 2 (Tph2) R439H mutation, analogous to the Tph2 R441H single-nucleotide polymorphism originally identified in a late life depression cohort, have markedly reduced levels of 5-hydroxytryptamine (5-HT). These Tph2KI mice are therefore...

  8. Tryptophan Requirement of the Enterally Fed Term Infant in the First Month of Life

    NARCIS (Netherlands)

    Huang, L.S.; Hogewind-Schoonenboom, J.E.; Zhu, L.; Kraaijenga, J.V.S.; van Haren, N.P.C.; Voortman, G.J.; Schierbeek, H.; Twisk, J.W.R.; Huang, Y.; Chen, C.; van Goudoever, J.B.

    2014-01-01

    OBJECTIVES: Tryptophan not only is an amino acid essential to protein synthesis but also serves as a precursor in 2 important metabolic pathways: the serotonin and the kynurenine pathways. Tryptophan is related to sleeping patterns. The objective of the present study was to determine the tryptophan

  9. Dimeric Complexes of Tryptophan with M2+ Metal Ions

    NARCIS (Netherlands)

    Dunbar, R. C.; Steill, J. D.; Polfer, N. C.; Oomens, J.

    2009-01-01

    IRMPD spectroscopy using the FELIX free electron laser and a Fourier transform ICR mass spectrometer was used to characterize the structures of electrosprayed dimer complexes M(2+)Trp(2) of tryptophan with a series of eight doubly charged metal ions, including alkaline earths Ca, Sr, and Ba, and

  10. Tryptophan Levels during Grape Ripening: Effects of Cultural Practices

    Directory of Open Access Journals (Sweden)

    Ana Ruiz-Rodríguez

    2017-06-01

    Full Text Available Some cultural practices that are carried out during the grape ripening period are associated with vine stress, including leaf removal, grape bunch removal, and vegetable cover crops. Additionally, several nitrogen and sulfur supplements have also been used directly on leaves during the last stage of the ripening period. In the work described here, five different cultural practices and the reference were applied in three replicates in the same vineyard. The evolution of tryptophan levels was evaluated from just after grape veraison until the harvest date. In some cases, certain specific treatments were also evaluated after the regular harvest date. The cultural techniques that involved the application of nitrogen led to higher levels of tryptophan at the harvest day when compared to other cultural techniques. It was also found that the application of nitrogen without sulfur had a faster effect on the level of tryptophan. It was established that a period of around 20 days is needed for the grapes to show clear differences in tryptophan levels after the application of nitrogen.

  11. Binding of tryptophan and iron by reptilion plasnna proteins

    African Journals Online (AJOL)

    transport functions. Albumin of the alligator (Alligator mississippiensis) and other reptiles binds, amongst other ions, tryptophan (McMenamy & Watson 1968) and transferrin binds iron (Barber & Sheeler 1963). Multiple transferrins are present in the plasma of many reptiles. (Dessauer et af 1962) and the albumin region of the.

  12. Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection.

    Science.gov (United States)

    Boyle, M A; O'Donnell, M J; Russell, R J; Galvin, N; Swan, J; Coleman, D C

    2015-10-01

    Decontaminating dental chair unit (DCU) suction systems in a convenient, safe and effective manner is problematic. This study aimed to identify and quantify the extent of the problems using 25 DCUs, methodically eliminate these problems and develop an efficient approach for reliable, effective, automated disinfection. DCU suction system residual contamination by environmental and human-derived bacteria was evaluated by microbiological culture following standard aspiration disinfection with a quaternary ammonium disinfectant or alternatively, a novel flooding approach to disinfection. Disinfection of multicomponent suction handpieces, assembled and disassembled, was also studied. A prototype manual and a novel automated Suction Tube Cleaning System (STCS) were developed and tested, as were novel single component suction handpieces. Standard aspiration disinfection consistently failed to decontaminate DCU suction systems effectively. Semi-confluent bacterial growth (101-500 colony forming units (CFU) per culture plate) was recovered from up to 60% of suction filter housings and from up to 19% of high and 37% of low volume suction hoses. Manual and automated flood disinfection of DCU suction systems reduced this dramatically (ranges for filter cage and high and low volume hoses of 0-22, 0-16 and 0-14CFU/plate, respectively) (P<0.0001). Multicomponent suction handpieces could not be adequately disinfected without prior removal and disassembly. Novel single component handpieces, allowed their effective disinfection in situ using the STCS, which virtually eliminated contamination from the entire suction system. Flood disinfection of DCU suction systems and single component handpieces radically improves disinfection efficacy and considerably reduces potential cross-infection and cross-contamination risks. DCU suction systems become heavily contaminated during use. Conventional disinfection does not adequately control this. Furthermore, multicomponent suction handpieces

  13. The role of tryptophan 2,3-dioxygenase in the hormonal control of tryptophan metabolism in isolated rat liver cells. Effects of glucocorticoids and experimental diabetes.

    OpenAIRE

    Salter, M; Pogson, C I

    1985-01-01

    The metabolism of L-tryptophan by isolated liver cells prepared from control, adrenalectomized, glucocorticoid-treated, acute-diabetic, chronic-diabetic and insulin-treated chronic-diabetic rats was studied. Liver cells from adrenalectomized rats metabolized tryptophan at rates comparable with the minimum diurnal rates of controls, but different from rates determined for cells from control rats 4h later. Administration of dexamethasone phosphate increased the activity of tryptophan 2,3-dioxyg...

  14. Laser Desorption of Tryptophan from Tryptophan-HCl Salt on a Graphite Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae Jun; Kim, Jeong Jin; Kang, Hyuk [Ajou University, Suwon (Korea, Republic of)

    2016-03-15

    Laser spectroscopy of biological molecules in the gas phase has been pioneered by Levy and coworkers when they first produced a supersonic molecular beam of tryptophan (Trp) and obtained its electronic spectrum. They were able to obtain enough vapor pressure needed for spectroscopy by heating a powder sample of Trp, although a special thermal spray was used to minimize fragmentation during heating. Many amine compounds, including biomolecules like amino acids and peptides, are usually available only as HCl salt form in order to prevent oxidation in air. Chemical processing is required to recover a neutral amine compound from its salt, thus limiting the applicability of laser-desorption spectroscopy of biomolecules. The experimental setup is a standard molecular beam machine composed of a pulsed valve with a laser-desorption module in a vacuum chamber, a second buffer chamber, a skimmer that separates the first and the second chambers, and a third vacuum chamber that is a time-of-flight mass spectrometer (TOF MS)

  15. Cloning and characterization of indole synthase (INS) and a putative tryptophan synthase α-subunit (TSA) genes from Polygonum tinctorium.

    Science.gov (United States)

    Jin, Zhehao; Kim, Jin-Hee; Park, Sang Un; Kim, Soo-Un

    2016-12-01

    Two cDNAs for indole-3-glycerol phosphate lyase homolog were cloned from Polygonum tinctorium. One encoded cytosolic indole synthase possibly in indigoid synthesis, whereas the other encoded a putative tryptophan synthase α-subunit. Indigo is an old natural blue dye produced by plants such as Polygonum tinctorium. Key step in plant indigoid biosynthesis is production of indole by indole-3-glycerol phosphate lyase (IGL). Two tryptophan synthase α-subunit (TSA) homologs, PtIGL-short and -long, were isolated by RACE PCR from P. tinctorium. The genome of the plant contained two genes coding for IGL. The short and the long forms, respectively, encoded 273 and 316 amino acid residue-long proteins. The short form complemented E. coli ΔtnaA ΔtrpA mutant on tryptophan-depleted agar plate signifying production of free indole, and thus was named indole synthase gene (PtINS). The long form, either intact or without the transit peptide sequence, did not complement the mutant and was tentatively named PtTSA. PtTSA was delivered into chloroplast as predicted by 42-residue-long targeting sequence, whereas PtINS was localized in cytosol. Genomic structure analysis suggested that a TSA duplicate acquired splicing sites during the course of evolution toward PtINS so that the targeting sequence-containing pre-mRNA segment was deleted as an intron. PtINS had about two to fivefolds higher transcript level than that of PtTSA, and treatment of 2,1,3-benzothiadiazole caused the relative transcript level of PtINS over PtTSA was significantly enhanced in the plant. The results indicate participation of PtINS in indigoid production.

  16. Conformational study of red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) by tryptophan fluorescence and differential scanning calorimetry.

    Science.gov (United States)

    Yin, Shou-Wei; Tang, Chuan-He; Yang, Xiao-Quan; Wen, Qi-Biao

    2011-01-12

    Fluorescence and differential scanning calorimetry (DSC) were used to study changes in the conformation of red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) under various environmental conditions. The possible relationship between fluorescence data and DSC characteristics was also discussed. Tryptophan fluorescence and fluorescence quenching analyses indicated that the tryptophan residues in KPI, exhibiting multiple fluorophores with different accessibilities to acrylamide, are largely buried in the hydrophobic core of the protein matrix, with positively charged side chains close to at least some of the tryptophan residues. GdnHCl was more effective than urea and SDS in denaturing KPI. SDS and urea caused variable red shifts, 2-5 nm, in the emission λ(max), suggesting the conformational compactness of KPI. The result was further supported by DSC characteristics that a discernible endothermic peak was still detected up to 8 M urea or 30 mM SDS, also evidenced by the absence of any shift in emission maximum (λ(max)) at different pH conditions. Marked decreases in T(d) and enthalpy (ΔH) were observed at extreme alkaline and/or acidic pH, whereas the presence of NaCl resulted in higher T(d) and ΔH, along with greater cooperativity of the transition. Decreases in T(d) and ΔH were observed in the presence of protein perturbants, for example, SDS and urea, indicating partial denaturation and decrease in thermal stability. Dithiothreitol and N-ethylmaleimide have a slight effect on the thermal properties of KPI. Interestingly, a close linear relationship between the T(d) (or ΔH) and the λ(max) was observed for KPI in the presence of 0-6 M urea.

  17. An optimized single chain TCR scaffold relying on the assembly with the native CD3-complex prevents residual mispairing with endogenous TCRs in human T-cells

    Science.gov (United States)

    Knies, Diana; Klobuch, Sebastian; Xue, Shao-An; Birtel, Matthias; Echchannaoui, Hakim; Yildiz, Oezlem; Omokoko, Tana; Guillaume, Philippe; Romero, Pedro; Stauss, Hans; Sahin, Ugur; Herr, Wolfgang; Theobald, Matthias; Thomas, Simone; Voss, Ralf-Holger

    2016-01-01

    Immunotherapy of cancer envisions the adoptive transfer of T-cells genetically engineered with tumor-specific heterodimeric α/β T-cell receptors (TCRα/β). However, potential mispairing of introduced TCRα/β-chains with endogenous β/α-ones may evoke unpredictable autoimmune reactivities. A novel single chain (sc)TCR format relies on the fusion of the Vα-Linker-Vβ-fragment to the TCR Cβ-domain and coexpression of the TCR Cα-domain capable of recruiting the natural CD3-complex for full and hence, native T-cell signaling. Here, we tested whether such a gp100(280-288)- or p53(264-272) tumor antigen-specific scTCR is still prone to mispairing with TCRα. In a human Jurkat-76 T-cell line lacking endogenous TCRs, surface expression and function of a scTCR could be reconstituted by any cointroduced TCRα-chain indicating mispairing to take place on a molecular basis. In contrast, transduction into human TCRα/β-positive T-cells revealed that mispairing is largely reduced. Competition experiments in Jurkat-76 confirmed the preference of dcTCR to selfpair and to spare scTCR. This also allowed for the generation of dc/scTCR-modified cytomegalovirus/tumor antigen-bispecific T-cells to augment T-cell activation in CMV-infected tumor patients. Residual mispairing was prevented by strenghtening the Vα-Li-Vβ-fragment through the design of a novel disulfide bond between a Vα- and a linker-resident residue close to Vβ. Multimer-stainings, and cytotoxicity-, IFNγ-secretion-, and CFSE-proliferation-assays, the latter towards dendritic cells endogenously processing RNA-electroporated gp100 antigen proved the absence of hybrid scTCR/TCRα-formation without impairing avidity of scTCR/Cα in T-cells. Moreover, a fragile cytomegalovirus pp65(495-503)-specific scTCR modified this way acquired enhanced cytotoxicity. Thus, optimized scTCR/Cα inhibits residual TCR mispairing to accomplish safe adoptive immunotherapy for bulk endogenous TCRα/β-positive T-cells. PMID:27028870

  18. Increased serum free tryptophan in patients with diarrhea-predominant irritable bowel syndrome.

    Science.gov (United States)

    Christmas, David M; Badawy, Abdulla A-B; Hince, Dana; Davies, Simon J C; Probert, Christopher; Creed, Tom; Smithson, John; Afzal, Muhammad; Nutt, David J; Potokar, John P

    2010-10-01

    Irregularities of serotonin function in irritable bowel syndrome (IBS) may be due to changes in the metabolism of the serotonin precursor l-tryptophan. Dietary alteration of tryptophan intake may impact upon the mood and bowel symptoms of IBS. We hypothesized that diarrhea-predominant irritable bowel syndrome (d-IBS) patients would exhibit an increase in plasma tryptophan due to alterations in tryptophan metabolism. We also hypothesized that a diet low in tryptophan would reverse this change and reduce symptoms. Thirteen patients with d-IBS had fasting serum free and total tryptophan, large neutral amino acids, and 6 kynurenine metabolites measured before and after 2 weeks of a strict dairy-free diet. Baseline tryptophan parameters were compared with an age- and sex-matched control group. Changes in the specific tryptophan parameters before and after dairy-free diet were correlated with symptoms of IBS and mood. Compared with the control group, d-IBS patients at baseline exhibited significantly higher free serum tryptophan (10.5 ± 4.35 vs 4.75 ± 2.43 μmol/L [means ± standard deviation], P = .006) and significantly lower tryptophan dioxygenase and total tryptophan oxidation as measured by the kynurenine to free tryptophan and total kynurenines to free tryptophan ratios (23.37 ± 10.12 vs 55.33 ± 16.02, P < .001 and 49.34 ± 17.84 vs 258.46 ± 98.67, P < .001, respectively). Dairy-free diet did not modulate metabolites of the kynurenine pathway or symptoms. Tryptophan metabolism along the kynurenine pathway is inhibited in d-IBS, and a dairy-free diet does not alter this. Our findings are consistent with possible enhanced serotonin activity in d-IBS. Copyright © 2010 Elsevier Inc. All rights reserved.

  19. Eficiência dos testes COPAN (Microplate e Single na detecção de resíduos de antimicrobianos no leite Efficacy of COPAN (Microplate and Single kits in detection of antimicrobials residues in milk

    Directory of Open Access Journals (Sweden)

    C.G.M.S.C. Tenório

    2009-04-01

    Full Text Available Avaliou-se a eficiência dos testes microbiológicos COPAN (Microplate e Single para detecção de resíduos de 13 antimicrobianos inoculados em leite isento de resíduos. Foram utilizadas quatro concentrações, sendo a primeira equivalente à metade do limite de detecção declarado pelo fabricante (C1; a segunda equivalente ao limite máximo de resíduos (LMR estabelecido pela legislação brasileira (C2; a terceira equivalente ao limite de detecção declarado pelo fabricante (C3; e a quarta equivalente ao dobro do limite de detecção declarado pelo fabricante (C4. Os testes apresentaram 100% de sensibilidade na detecção de amoxicilina, ampicilina, cloxacilina, penicilina, tilosina, sulfadiazina, sulfametoxazol, e 96,7% na detecção de oxacilina para as concentrações informadas pelo fabricante como limite de detecção. Em relação às concentrações estabelecidas pela legislação brasileira, verificou-se que os testes foram capazes de detectá-las para a maioria dos antimicrobianos avaliados. Os testes não se mostraram eficientes na detecção das concentrações estabelecidas pela legislação para eritromicina, oxitetraciclina, tetraciclina, trimetoprim e gentamicina (Microplate.The efficacy of the microbiological kits COPAN (Microplate and Single for detection of antimicrobials residues was tested. Thirteen drugs were inoculated into milk without residues at four concentration levels: C1 - half of the detection threshold declared by the manufacturer, C2 - the maximum residues threshold established by the Brazilian legislation, C3 - the detection threshold declared by the manufacturer, and C4 - two fold the detection threshold declared by the manufacturer. The tests showed 100% efficient in detection of amoxicillin, cloxacillin, penicillin, tilosin, sulfadiazine, and sulfa methoxazol; and 96.7% for oxacillin considering the concentration stated by the manufacturer as threshold level. Regarding the concentrations established by

  20. New oxidation and photo-oxidation products of tryptophan

    International Nuclear Information System (INIS)

    Savige, W.E.

    1975-01-01

    Dye-sensitized photo-oxidation of tryptophan in water gives N'-formylkynurenine and (+-)-3a-hydroxy-1,2,3a,8,8a-hexahydropyrrolo[2,3-b] indole-2-carboxylic acid. The latter rearranges to oxindolyl-3-alanine on irradiation with UV light and reacts with thiols, including cysteine, in warm 20% acetic acid to give the corresponding 2-tryptophyl sulphides. (orig.) [de

  1. Tryptophan Predicts the Risk for Future Type 2 Diabetes

    OpenAIRE

    Chen, Tianlu; Zheng, Xiaojiao; Ma, Xiaojing; Bao, Yuqian; Ni, Yan; Hu, Cheng; Rajani, Cynthia; Huang, Fengjie; Zhao, Aihua; Jia, Weiping; Jia, Wei

    2016-01-01

    Recently, 5 amino acids were identified and verified as important metabolites highly associated with type 2 diabetes (T2D) development. This report aims to assess the association of tryptophan with the development of T2D and to evaluate its performance with existing amino acid markers. A total of 213 participants selected from a ten-year longitudinal Shanghai Diabetes Study (SHDS) were examined in two ways: 1) 51 subjects who developed diabetes and 162 individuals who remained metabolically h...

  2. Coumarins as turn on/off fluorescent probes for detection of residual acetone in cosmetics following headspace single-drop microextraction.

    Science.gov (United States)

    Cabaleiro, N; de la Calle, I; Bendicho, C; Lavilla, I

    2014-11-01

    In this work, a new method based on headspace-single drop microextraction for the determination of residual acetone in cosmetics by microfluorospectrometry is proposed. Acetone causes fluorescence changes in a 2.5 µL-ethanolic drop (40% v/v) containing 3.10(-4) mol L(-1) 7-hydroxy-4-methylcoumarin ('turn off') or 6.10(-6) mol L(-1) 7-diethylamino-4-methylcoumarin ('turn on'). Polarity and ability to form hydrogen bonds of short chain alcohols (polar protic solvents) were crucial in order to observe these changes in the presence of acetone (polar aprotic solvent). Parameters related with the HS-SDME procedure were studied, namely headspace volume, composition, volume and temperature of drop, microextraction time, stirring rate, mass and temperature of sample, as well as the effect of potential interferents (alcohols and fragrances). The high volatility of acetone allows its extraction from an untreated cosmetic sample within 3 min. A detection limit of 0.26 µg g(-1) and repeatability, expressed as relative standard deviation, around 5% were reached. Accuracy of the proposed methodology was evaluated by means of recovery studies. The method was successfully used to analyze different cosmetics. Simplicity and high sample throughput can be highlighted. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. A Jerte Valley Cherry-Based Product as a Supply of Tryptophan

    Directory of Open Access Journals (Sweden)

    María Garrido

    2012-01-01

    Full Text Available L -Tryptophan (tryptophan is an essential amino acid in humans. It has important roles as a precursor of different bioactive compounds. Based on previous studies in which tryptophan has been shown to be present in fresh cherries, the aim of the present work was to analyze the tryptophan content of a Jerte Valley cherry-based product. A previously optimized method of analysis of tryptophan was used, ie, high-performance liquid chromatography with fluorescence detection (HPLC/FL. As expected, HPLC/FL technique permitted to detect and quantify the tryptophan content in a different matrix rather than fresh cherries. In fact, the Jerte Valley cherry-based product contained 69.54 ± 10.64 ppm of tryptophan, thereby showing that this product is a good source of tryptophan. In summary, it has been proven that the Jerte Valley cherry-based product is rich in tryptophan and may be indicated as a supply of this essential amino acid as well as having potential health benefits for conditions where tryptophan is necessary.

  4. Heme-containing enzymes and inhibitors for tryptophan metabolism.

    Science.gov (United States)

    Yan, Daojing; Lin, Ying-Wu; Tan, Xiangshi

    2017-09-20

    Iron-containing enzymes such as heme enzymes play crucial roles in biological systems. Three distinct heme-containing dioxygenase enzymes, tryptophan 2,3-dioxygenase (TDO), indoleamine 2,3-dioxygenase 1 (IDO1) and indoleamine 2,3-dioxygenase 2 (IDO2) catalyze the initial and rate-limiting step of l-tryptophan catabolism through the kynurenine pathway in mammals. Overexpression of these enzymes causes depletion of tryptophan and the accumulation of metabolic products, which contributes to tumor immune tolerance and immune dysregulation in a variety of disease pathologies. In the past few decades, IDO1 has garnered the most attention as a therapeutic target with great potential in cancer immunotherapy. Many potential inhibitors of IDO1 have been designed, synthesized and evaluated, among which indoximod (d-1-MT), INCB024360, GDC-0919 (formerly NLG-919), and an IDO1 peptide-based vaccine have advanced to the clinical trial stage. However, recently, the roles of TDO and IDO2 have been elucidated in immune suppression. In this review, the current drug discovery landscape for targeting TDO, IDO1 and IDO2 is highlighted, with particular attention to the recent use of drugs in clinical trials. Moreover, the crystal structures of these enzymes, in complex with inhibitors, and the mechanisms of Trp catabolism in the first step, are summarized to provide information for facilitating the discovery of new enzyme inhibitors.

  5. Kinetics and mechanism of the condensation of pyridoxal hydrochloride with L-tryptophan and D-tryptophan, and the chemical transformation of their products

    Science.gov (United States)

    Pishchugin, F. V.; Tuleberdiev, I. T.

    2017-10-01

    The kinetics and mechanism of interaction between pyridoxal and L-tryptophan, D-tryptophan, and their derivatives are studied. It is found that condensation reactions proceed via three kinetically distinguishable stages: (1) the rapid intraplanar addition of the NH2 groups of the amino acids to pyridoxal with the formation of amino alcohols; (2) the rotational isomerism of amino alcohol fragments with their subsequent dehydration and the formation of a Schiff base with a specific configuration; (3) the abstraction of α-hydrogen in the product of condensation of pyridoxal with L-tryptophan, or the abstraction of CO2 in the product of condensation of pyridoxal with D-tryptophan with the formation of quinoid structures, hydrolysis of which results in the preparation of pyridoxamine and keto acid or pyridoxal and tryptamine, respectively. Schiff bases resistant to further chemical transformations are formed in the reaction with tryptophan methyl ester.

  6. Internet-Based Cognitive Behavioral Therapy for Residual Symptoms in Bipolar Disorder Type II: A Single-Subject Design Pilot Study.

    Science.gov (United States)

    Holländare, Fredrik; Eriksson, Annsofi; Lövgren, Lisa; Humble, Mats B; Boersma, Katja

    2015-04-23

    Bipolar disorder is a chronic condition with recurring episodes that often lead to suffering, decreased functioning, and sick leave. Pharmacotherapy in the form of mood stabilizers is widely available, but does not eliminate the risk of a new depressive or (hypo)manic episode. One way to reduce the risk of future episodes is to combine pharmacological treatment with individual or group psychological interventions. However, access to such interventions is often limited due to a shortage of trained therapists. In unipolar depression there is now robust evidence of the effectiveness of Internet-based psychological interventions, usually comprising psychoeducation and cognitive behavioral therapy (CBT). Internet-based interventions for persons suffering from bipolar disorder could increase access to psychological treatment. The aim of this study was to investigate the feasibility of an Internet-based intervention, as well as its effect on residual depressive symptoms in persons diagnosed with bipolar disorder type II (BP-II). The most important outcomes were depressive symptoms, treatment adherence, and whether the patient perceived the intervention as helpful. A total of 7 patients diagnosed with bipolar disorder type II at a Swedish psychiatric outpatient clinic were offered the opportunity to participate. Of the 7 patients, 3 (43%) dropped out before treatment began, and 4 (57%) were treated by means of an online, Internet-based intervention based on CBT (iCBT). The intervention was primarily aimed at psychoeducation, treatment of residual depressive symptoms, emotion regulation, and improved sleep. All patients had ongoing pharmacological treatment at recruitment and established contact with a psychiatrist. The duration of BP-II among the treated patients was between 6 and 31 years. A single-subject design was used and the results of the 4 participating patients were presented individually. Initiating treatment was perceived as too demanding under current life

  7. Digestible tryptophan levels for male broilers in pre-starter and starter diets

    Directory of Open Access Journals (Sweden)

    Bruno Samuel Borges

    2016-09-01

    Full Text Available The objective was to determine the digestible tryptophan requirements for male broilers in pre-starter and starter phases. Two experiments using 400 Cobb broilers were performed 200 males in the first experiment for the pre-starter phase (one to seven days old, and 200 males in the second experiment for the starter phase (eight to 21 days old. Chicks were housed in batter boxes made of galvanized steel as an experimental shed. The experiments were performed in a completely randomized design, with four treatments and five replicates, with ten birds each. In both experiments, the tryptophan requirement was determined using diets with different levels of digestible tryptophan. A tryptophan-deficient diet was formulated, as a basal diet, which was supplemented with increased levels of L-tryptophan in order to achieve the desirable digestible tryptophan levels. Treatments consisted of 0.209% (basal diet; 0.223%; 0.235% and 0.248% digestible tryptophan for the pre-starter phase (experiment 1 and 0.187% (basal diet; 0.200%, 0.211% and 0.223% digestible tryptophan for the starter phase (experiment 2. We evaluated feed intake, weight gain and feed conversion, as well as the metabolizability of feed nutrients. The performance and metabolic data were subjected to analysis of variance, and estimates of digestible tryptophan levels were made through polynomial regression models at 5% probability. There was no significant difference between the digestible tryptophan levels in the diet over performance and digestibility in both treatments. It is possible to conclude that the basal diet with 0.209% digestible tryptophan for the pre-starter phase and 0.187% for the starter phase, at a tryptophan: lysine ratio of 16%, as sufficient to meet the broilers requirements.

  8. Suppression of aggression in rainbow trout (Oncorhynchus mykiss) by dietary L-tryptophan.

    Science.gov (United States)

    Winberg, S; Øverli, Ø; Lepage, O

    2001-11-01

    Juvenile rainbow trout Oncorhynchus mykiss were isolated in individual compartments in observation aquaria and allowed to acclimate for 1 week, during which they were fed commercial trout feed. Thereafter, the fish were tested for aggressive behaviour using a resident/intruder test. Following this first resident/intruder test, the feed was exchanged for an experimental wet feed supplemented with 0.15 % or 1.5 % L-tryptophan (by wet mass). Controls received the same feed but without L-tryptophan supplementation. The fish were fed to satiety daily, and their individual feed intake was recorded. Aggressive behaviour was quantified again after 3 and 7 days of L-tryptophan feeding using the resident/intruder test. Feeding the fish L-tryptophan-supplemented feed for 3 days had no effect on aggressive behaviour, whereas feeding the fish L-tryptophan-supplemented feed for 7 days significantly suppressed aggressive behaviour in the fish, an effect seen at both levels of L-tryptophan supplementation. Fish fed L-tryptophan-supplemented feed showed elevated plasma and brain levels of L-tryptophan. The amino acid L-tryptophan is the precursor of serotonin, and supplementary dietary L-tryptophan was found to elevate levels of 5-hydroxyindoleacetic acid (5-HIAA) and the 5-HIAA/serotonin concentration ratio in the brain. Neither feed intake nor plasma cortisol level was significantly affected by dietary L-tryptophan. Central serotonin is believed to have an inhibitory effect on aggressive behaviour, and it is suggested that the suppressive effect of dietary L-tryptophan on aggressive behaviour is mediated by an elevation of brain serotonergic activity.

  9. Structure-function paradigm in human myoglobin: how a single-residue substitution affects NO reactivity at low pO2.

    Science.gov (United States)

    Scorciapino, Mariano Andrea; Spiga, Enrico; Vezzoli, Alessandra; Mrakic-Sposta, Simona; Russo, Rosaria; Fink, Bruno; Casu, Mariano; Gussoni, Maristella; Ceccarelli, Matteo

    2013-05-22

    This work is focused on the two more expressed human myoglobin isoforms. In the literature, their different overexpression in high-altitude natives was proposed to be related to alternative/complementary functions in hypoxia. Interestingly, they differ only at residue-54, lysine or glutamate, which is external and far from the main binding site. In order to ascertain whether these two almost identical myoglobins might exert different functions and to contribute to a deeper understanding about myoglobin's oxygen-level dependent functioning, they have been compared with respect to dynamics, heme electronic structure, and NO reactivity at different O2 levels. Electron paramagnetic resonance (EPR) spectroscopy was employed to investigate the electronic structure of the nitrosyl-form, obtaining fundamental clues about a different bond interaction between the heme-iron and the proximal histidine and highlighting striking differences in NO reactivity, especially at a very low pO2. The experimental results well matched with the information provided by molecular dynamics simulations, which showed a significantly different dynamics for the two proteins only in the absence of O2. The single mutation differentiating the two myoglobins resulted in strongly affecting the plasticity of the CD-region (C-helix-loop-D-helix), whose fluctuations, being coupled to the solvent, were found to be correlated with the dynamics of the distal binding site. In the absence of O2, on the one hand a significantly different probability for the histidine-gate opening has been shown by MD simulations, and on the other a different yield of myoglobin-NO formation was experimentally observed through EPR.

  10. Online single particle analysis of ice particle residuals from mountain-top mixed-phase clouds using laboratory derived particle type assignment

    Science.gov (United States)

    Schmidt, Susan; Schneider, Johannes; Klimach, Thomas; Mertes, Stephan; Schenk, Ludwig Paul; Kupiszewski, Piotr; Curtius, Joachim; Borrmann, Stephan

    2017-01-01

    In situ single particle analysis of ice particle residuals (IPRs) and out-of-cloud aerosol particles was conducted by means of laser ablation mass spectrometry during the intensive INUIT-JFJ/CLACE campaign at the high alpine research station Jungfraujoch (3580 m a.s.l.) in January-February 2013. During the 4-week campaign more than 70 000 out-of-cloud aerosol particles and 595 IPRs were analyzed covering a particle size diameter range from 100 nm to 3 µm. The IPRs were sampled during 273 h while the station was covered by mixed-phase clouds at ambient temperatures between -27 and -6 °C. The identification of particle types is based on laboratory studies of different types of biological, mineral and anthropogenic aerosol particles. The outcome of these laboratory studies was characteristic marker peaks for each investigated particle type. These marker peaks were applied to the field data. In the sampled IPRs we identified a larger number fraction of primary aerosol particles, like soil dust (13 ± 5 %) and minerals (11 ± 5 %), in comparison to out-of-cloud aerosol particles (2.4 ± 0.4 and 0.4 ± 0.1 %, respectively). Additionally, anthropogenic aerosol particles, such as particles from industrial emissions and lead-containing particles, were found to be more abundant in the IPRs than in the out-of-cloud aerosol. In the out-of-cloud aerosol we identified a large fraction of aged particles (31 ± 5 %), including organic material and secondary inorganics, whereas this particle type was much less abundant (2.7 ± 1.3 %) in the IPRs. In a selected subset of the data where a direct comparison between out-of-cloud aerosol particles and IPRs in air masses with similar origin was possible, a pronounced enhancement of biological particles was found in the IPRs.

  11. Nuclear magnetic resonance study of interaction of ligands with Streptococcus faecium dihydrofolate reductase labeled with [#betta#-13C]tryptophan

    International Nuclear Information System (INIS)

    London, R.E.; Groff, J.P.; Cocco, L.; Blakley, R.L.

    1982-01-01

    Dihydrofolate reductase from Streptococcus faecium has been labeled with [#betta#- 13 C]tryptophan. We have determined changes occurring in the chemical shifts and line widths of the four resonances of the 13 C NMR spectrum of the labeled enzyme, due to its interaction with various ligands. These include the coenzyme, NPDPH and related nucleotides, folate and its polyglutamate derivatives, and many inhibitors including methotrexate and trimethoprim. In addition, paramagnetic relaxation effects produced by a bound spin-labeled analogue of 2'-phosphoadenosine-5'-diphosphoribose on the tryptophan C/sup #betta#/ carbons have been measured. Distances calculated from the relaxation data have been compared with corresponding distances in the crystallographic model of the NADPH-methotrexate ternary complex of Lactobacillus casei reductase. The paramagnetic relaxation data indicate that the two downfield resonances (1 and 2) correspond to tryptophans (W/sub A/ and W/sub B/) that are more remote from the catalytic site, and from the crystallographic model these are seen to be Trp-115 and Trp-160. The upfield resonances (3 and 4) that show broadening due to chemical exchange correspond to closer residues (W/sub C/ and W/sub D/), and these are identified with Trp-6 and Trp-22. However, the relaxation data do not permit specific assignments within the nearer and farther pairs. Although resonance 3, which is split due to chemical exchange, was formerly assigned to Trp-6, data obtained for the enzyme in the presence of various ligands are better interpreted if resonance 3 is assigned to Trp-22, which is located on a loop that joins elements of secondary structure and forms one side of the ligand-binding cavity

  12. In-situ single particle composition analysis of free tropospheric ice nuclei and ice residues in mixed-phase clouds during INUIT-JFJ 2013

    Science.gov (United States)

    Schmidt, Susan; Schneider, Johannes; Thomas, Klimach; Stephan, Mertes; Ludwig, Schenk; Udo, Kästner; Frank, Stratmann; Joachim, Curtius; Piotr, Kupiszewski; Ernest, Weingartner; Emanuel, Hammer; Paul, Vochezer; Martin, Schnaiter; Stephan, Borrmann

    2014-05-01

    In the framework of the DFG (deutsche Forschungsgemeinschaft)-funded research unit INUIT (Ice Nuclei research UnIT) a field campaign at the High Alpine Research Station Jungfraujoch (JFJ, Swiss Alps, Sphinx Laboratory, 3580 m asl; 7°59'2''E, 46°32'53''N) took place in January/February 2013 (INUIT-JFJ 2013). The goal of the measurements was to investigate the chemical composition of ice particle residues (IPR) in ambient air as well as the background aerosol particles. Previous investigations conducted at the JFJ showed that particles consisting of mineral components dominate the ice particle residue number (Kamphus et al., 2008) but also particles consisting of black carbon were found to be enriched in IPR (Mertes et al., 2007; Cozic et al., 2008). Cziczo et al. find out that lead as well is a good ice nucleus and was measured in IPR at previous measurements at the JFJ. During INUIT-JFJ 2013, the IPR were sampled out of mixed-phase clouds by an Ice-CVI (Ice Counterflow Virtual Impactor, Mertes et al., 2007) and an ISI (Ice Selective Inlet, Kupiszewski et al., 2013) and analyzed by the single particle mass spectrometer ALABAMA (Aircraft-based Laser Ablation Aerosol Mass Spectrometer; Brands et al., 2011). Additionally, the ALABAMA was connected to a total aerosol-inlet to investigate the chemical composition of background aerosol particles. During 217 hours of background aerosol measurements we analyzed more than 27000 aerosol particles, which consisted mainly of pure organic components or organics mixed with ammonium, metals or mineral components. During six cloud events with approximately 63 h measurement time we detected 162 IPR sampled by the Ice-CVI. The main part of these IPR were also composed of organic material mixed with other chemical compounds. Additionally, we found particles which consisted of mineral components (approximately 23 %). Sampling mixed-phase cloud through the ISI we measured during four cloud events 34 ice residues in approximately 30 h

  13. Gallium uptake in tryptophan-related pulmonary disease

    International Nuclear Information System (INIS)

    Kim, S.M.; Park, C.H.; Intenzo, C.M.; Patel, R.

    1991-01-01

    We describe a patient who developed fever, fatigue, muscle weakness, dyspnea, skin rash, and eosinophilia after taking high doses of tryptophan for insomnia for two years. A gallium-67 scan revealed diffuse increased uptake in the lung and no abnormal uptake in the muscular distribution. Bronchoscopy and biopsy confirmed inflammatory reactions with infiltration by eosinophils, mast cells, and lymphocytes. CT scan showed an interstitial alveolar pattern without fibrosis. EMG demonstrated diffuse myopathy. Muscle biopsy from the right thigh showed an inflammatory myositis with eosinophilic and lymphocytic infiltrations

  14. Antihypertensive and cardioprotective effects of the dipeptide isoleucine-tryptophan and whey protein hydrolysate.

    Science.gov (United States)

    Martin, M; Kopaliani, I; Jannasch, A; Mund, C; Todorov, V; Henle, T; Deussen, A

    2015-12-01

    Angiotensin-converting enzyme inhibitors are treatment of choice in hypertensive patients. Clinically used inhibitors exhibit a structural similarity to naturally occurring peptides. This study evaluated antihypertensive and cardioprotective effects of ACE-inhibiting peptides derived from food proteins in spontaneously hypertensive rats. Isoleucine-tryptophan (in vitro IC50 for ACE = 0.7 μm), a whey protein hydrolysate containing an augmented fraction of isoleucine-tryptophan, or captopril was given to spontaneously hypertensive rats (n = 60) over 14 weeks. Two further groups, receiving either no supplement (Placebo) or intact whey protein, served as controls. Systolic blood pressure age-dependently increased in the Placebo group, whereas the blood pressure rise was effectively blunted by isoleucine-tryptophan, whey protein hydrolysate and captopril (-42 ± 3, -38 ± 5, -55 ± 4 mm Hg vs. Placebo). At study end, myocardial mass was lower in isoleucine-tryptophan and captopril groups but only partially in the hydrolysate group. Coronary flow reserve (1 μm adenosine) was improved in isoleucine-tryptophan and captopril groups. Plasma ACE activity was significantly decreased in isoleucine-tryptophan, hydrolysate and captopril groups, but in aortic tissue only after isoleucine-tryptophan or captopril treatment. This was associated with lowered expression and activity of matrix metalloproteinase-2. Following isoleucine-tryptophan and captopril treatments, gene expression of renin was significantly increased indicating an active feedback within renin-angiotensin system. Whey protein hydrolysate and isoleucine-tryptophan powerfully inhibit plasma ACE resulting in antihypertensive effects. Moreover, isoleucine-tryptophan blunts tissue ACE activity, reduces matrix metalloproteinase-2 activity and improves coronary flow reserve. Thus, whey protein hydrolysate and particularly isoleucine-tryptophan may serve as innovative food additives with the goal of attenuating

  15. Aberrant tryptophan transport in cultured fibroblast from patients with Male Idiopathic Osteoporosis: An in vitro study

    Directory of Open Access Journals (Sweden)

    Ylva Pernow

    2018-06-01

    Full Text Available It has been demonstrated, that long-term chronic tryptophan deficiency, results in decreased serotonin synthesis, which may lead to low bone mass and low bone formation. Findings from studies in male patients with idiopathic osteoporosis suggested a decreased transport of tryptophan in erythrocytes of osteoporotic patients, indicating that serotonin system defects may be involved in the etiology of low bone mass. Tryptophan is the precursor of serotonin, and a disturbed transport of tryptophan is implicated in altered serotonin synthesis. However, no study has investigated the tryptophan transport kinetics in MIO patients. The aim of this study is to investigate the kinetic parameters of tryptophan transport in fibroblasts derived from MIO patients compared to age and sex matched controls.Fibroblast cells were cultured from skin biopsies obtained from 14 patients diagnosed with Male Idiopathic Osteoporosis and from 13 healthy age-sex matched controls, without a diagnosis of osteoporosis. Transport of the amino acid tryptophan across the cell membrane was measured by the cluster tray method. The kinetic parameters, maximal transport capacity (Vmax and affinity constant (Km were determined by using the Lineweaver-Burke plot equation.The results of this study have shown a significantly lower mean value for Vmax (p=0.0138 and lower Km mean value (p=0.0009 of tryptophan transport in fibroblasts of MIO patients compared to the control group. A lower Vmax implied a decreased tryptophan transport availability in MIO patients.In conclusion, reduced cellular tryptophan availability in MIO patients might result in reduced brain serotonin synthesis and its endogenous levels in peripheral tissues, and this may contribute to low bone mass/formation. The findings of the present study could contribute to the etiology of idiopathic osteoporosis and for the development of novel approaches for diagnosis, treatment and management strategies of MIO. Keywords: Male

  16. Residual stresses

    International Nuclear Information System (INIS)

    Sahotra, I.M.

    2006-01-01

    The principal effect of unloading a material strained into the plastic range is to create a permanent set (plastic deformation), which if restricted somehow, gives rise to a system of self-balancing within the same member or reaction balanced by other members of the structure., known as residual stresses. These stresses stay there as locked-in stresses, in the body or a part of it in the absence of any external loading. Residual stresses are induced during hot-rolling and welding differential cooling, cold-forming and extruding: cold straightening and spot heating, fabrication and forced fitting of components constraining the structure to a particular geometry. The areas which cool more quickly develop residual compressive stresses, while the slower cooling areas develop residual tensile stresses, and a self-balancing or reaction balanced system of residual stresses is formed. The phenomenon of residual stresses is the most challenging in its application in surface modification techniques determining endurance mechanism against fracture and fatigue failures. This paper discusses the mechanism of residual stresses, that how the residual stresses are fanned and what their behavior is under the action of external forces. Such as in the case of a circular bar under limit torque, rectangular beam under limt moment, reclaiming of shafts welds and peening etc. (author)

  17. Tryptophan Biochemistry: Structural, Nutritional, Metabolic, and Medical Aspects in Humans.

    Science.gov (United States)

    Palego, Lionella; Betti, Laura; Rossi, Alessandra; Giannaccini, Gino

    2016-01-01

    L-Tryptophan is the unique protein amino acid (AA) bearing an indole ring: its biotransformation in living organisms contributes either to keeping this chemical group in cells and tissues or to breaking it, by generating in both cases a variety of bioactive molecules. Investigations on the biology of Trp highlight the pleiotropic effects of its small derivatives on homeostasis processes. In addition to protein turn-over, in humans the pathways of Trp indole derivatives cover the synthesis of the neurotransmitter/hormone serotonin (5-HT), the pineal gland melatonin (MLT), and the trace amine tryptamine. The breakdown of the Trp indole ring defines instead the "kynurenine shunt" which produces cell-response adapters as L-kynurenine, kynurenic and quinolinic acids, or the coenzyme nicotinamide adenine dinucleotide (NAD(+)). This review aims therefore at tracing a "map" of the main molecular effectors in human tryptophan (Trp) research, starting from the chemistry of this AA, dealing then with its biosphere distribution and nutritional value for humans, also focusing on some proteins responsible for its tissue-dependent uptake and biotransformation. We will thus underscore the role of Trp biochemistry in the pathogenesis of human complex diseases/syndromes primarily involving the gut, neuroimmunoendocrine/stress responses, and the CNS, supporting the use of -Omics approaches in this field.

  18. Tryptophan autofluorescence imaging of neoplasms of the human colon

    Science.gov (United States)

    Banerjee, Bhaskar; Renkoski, Timothy; Graves, Logan R.; Rial, Nathaniel S.; Tsikitis, Vassiliki Liana; Nfonsom, Valentine; Pugh, Judith; Tiwari, Piyush; Gavini, Hemanth; Utzinger, Urs

    2012-01-01

    Detection of flat neoplasia is a major challenge in colorectal cancer screening, as missed lesions can lead to the development of an unexpected `incident' cancer prior to the subsequent endoscopy. The use of a tryptophan-related autofluorescence has been reported to be increased in murine intestinal dysplasia. The emission spectra of cells isolated from human adenocarcinoma and normal mucosa of the colon were studied and showed markedly greater emission intensity from cancerous cells compared to cells obtained from the surrounding normal mucosa. A proto-type multispectral imaging system optimized for ultraviolet macroscopic imaging of tissue was used to obtain autofluorescence images of surgical specimens of colonic neoplasms and normal mucosa after resection. Fluorescence images did not display the expected greater emission from the tumor as compared to the normal mucosa, most probably due to increased optical absorption and scattering in the tumors. Increased fluorescence intensity in neoplasms was observed however, once fluorescence images were corrected using reflectance images. Tryptophan fluorescence alone may be useful in differentiating normal and cancerous cells, while in tissues its autofluorescence image divided by green reflectance may be useful in displaying neoplasms.

  19. Introduction of a tryptophan side chain into subsite +1 enhances transglycosylation activity of a GH-18 chitinase from Arabidopsis thaliana, AtChiC

    DEFF Research Database (Denmark)

    Umemoto, Naoyuki; Ohnuma, Takayuki; Mizuhara, Mamiko

    2013-01-01

    A tryptophan side chain was introduced into subsite +1 of family GH-18 (class V) chitinases from Nicotiana tabacum and Arabidopsis thaliana (NtChiV and AtChiC, respectively) by the mutation of a glycine residue to tryptophan (G74W-NtChiV and G75W-AtChiC). The specific activity toward glycol chitin...... of the two mutant enzymes was 70-71% of that of the wild type. Using chitin oligosaccharides, (GlcNAc)(n) (n = 4, 5 and 6), as the substrates, we found the transglycosylation reaction to be significantly enhanced in G74W-NtChiV and G75W-AtChiC when compared with the corresponding wild-type enzymes....... The introduced tryptophan side chain might protect the oxazolinium ion intermediate from attack by a nucleophilic water molecule. The enhancement of transglycosylation activity was much more distinct in G75W-AtChiC than in G74W-NtChiV. Nuclear magnetic resonance titration experiments using the inactive double...

  20. Photoinduced electron transfer involving eosin-tryptophan conjugates. Long-lived radical pair states for systems incorporating aromatic amino acid side chains

    Energy Technology Data Exchange (ETDEWEB)

    Jones, G. II; Farahat, C.W.; Oh, C. (Boston Univ., MA (United States))

    1994-07-14

    The electron-transfer photochemistry of the covalent derivatives of the dye eosin, in which the xanthene dye is covalently attached to the amino acid L-tryptophan via the thiohydantoin derivative, the tryptophan dipeptide, and an ethyl ester derivative, has been investigated. The singlet excited state of the dye is significantly quenched on attachment of the aromatic amino acid residue. Dye triplet states are also intercepted through intramolecular interaction of excited dye and amino acid pendants. Flash photolysis experiments verify that this interaction involves electron transfer from the indole side chains of tryptophan. Rate constants for electron transfer are discussed in terms of the distance relationships for the eosin chromophore and aromatic redox sites on peptide derivatives, the pathway for [sigma]-[pi] through-bond interaction between redox sites, and the multiplicity and state of protonation for electron-transfer intermediates. Selected electron-transfer photoreactions were studied under conditions of binding of the peptide derivatives in a high molecular weight, water-soluble, globular polymer, poly(vinyl-2-pyrrolidinone). 28 refs., 4 figs., 1 tab.

  1. Cell Adhesion on RGD-Displaying Knottins with Varying Numbers of Tryptophan Amino Acids to Tune the Affinity for Assembly on Cucurbit[8]uril Surfaces.

    Science.gov (United States)

    Sankaran, Shrikrishnan; Cavatorta, Emanuela; Huskens, Jurriaan; Jonkheijm, Pascal

    2017-09-05

    Cell adhesion is studied on multivalent knottins, displaying RGD ligands with a high affinity for integrin receptors, that are assembled on CB[8]-methylviologen-modified surfaces. The multivalency in the knottins stems from the number of tryptophan amino acid moieties, between 0 and 4, that can form a heteroternary complex with cucurbit[8]uril (CB[8]) and surface-tethered methylviologen (MV 2+ ). The binding affinity of the knottins with CB[8] and MV 2+ surfaces was evaluated using surface plasmon resonance spectroscopy. Specific binding occurred, and the affinity increased with the valency of tryptophans on the knottin. Additionally, increased multilayer formation was observed, attributed to homoternary complex formation between tryptophan residues of different knottins and CB[8]. Thus, we were able to control the surface coverage of the knottins by valency and concentration. Cell experiments with mouse myoblast (C2C12) cells on the self-assembled knottin surfaces showed specific integrin recognition by the RGD-displaying knottins. Moreover, cells were observed to elongate more on the supramolecular knottin surfaces with a higher valency, and in addition, more pronounced focal adhesion formation was observed on the higher-valency knottin surfaces. We attribute this effect to the enhanced coverage and the enhanced affinity of the knottins in their interaction with the CB[8] surface. Collectively, these results are promising for the development of biomaterials including knottins via CB[8] ternary complexes for tunable interactions with cells.

  2. Results of correlation of values of individual behaviour of rats with liver tryptophan pyrrolase activity.

    Science.gov (United States)

    Tikal, K; Kunz, K

    1976-01-01

    A significant negative correlation was found between the individual animal's horizontal activity in an open field and liver tryptophan pyrrolase (LTP) activity. On the other hand, the duration of immobility in an open field correlated postively and significantly with liver tryptophan pyrrolase activity.

  3. Inhibition of hormonal and behavioral effects of stress by tryptophan in rats.

    Science.gov (United States)

    Gul, Sumera; Saleem, Darakhshan; Haleem, Muhammad A; Haleem, Darakhshan Jabeen

    2017-11-03

    Stress in known to alter hormonal systems. Pharmacological doses of tryptophan, the essential amino acid precursor of serotonin, increase circulating leptin and decrease ghrelin in normal healthy adults. Because systemically injected leptin inhibits stress-induced behavioral deficits and systemically injected serotonin modulates leptin release from the adipocytes, we used tryptophan as a pharmacological tool to modulate hormonal and behavioral responses in unstressed and stressed rats. Leptin, ghrelin, serotonin, tryptophan, and behavior were studied in unstressed and stressed rats following oral administration of 0, 100, 200, and 300 mg/kg of tryptophan. Following oral administration of tryptophan at a dose of 300 mg/kg, circulating levels of serotonin and leptin increased and those of ghrelin decreased in unstressed animals. No effect occurred on 24-hours cumulative food intake and elevated plus maze performance. Exposure to 2 hours immobilization stress decreased 24 hours cumulative food intake and impaired performance in elevated plus maze monitored next day. Serum serotonin decreased, leptin increased, and no effect occurred on ghrelin. Stress effects on serotonin, leptin, food intake, and elevated plus maze performance did not occur in tryptophan-pretreated animals. Tryptophan-induced decreases of ghrelin also did not occur in stressed animals. The findings show an important role of serum serotonin, leptin, and ghrelin in responses to stress and suggest that the essential amino acid tryptophan can improve therapeutics in stress-induced hormonal and behavioral disorders.

  4. Delaying aging and the aging-associated decline in protein homeostasis by inhibition of tryptophan degradation

    NARCIS (Netherlands)

    van der Goot, Annemieke T.; Zhu, Wentao; Vazquez-Manrique, Rafael P.; Seinstra, Renee I.; Dettmer, Katja; Michels, Helen; Farina, Francesca; Krijnen, Jasper; Melki, Ronald; Buijsman, Rogier C.; Silva, Mariana Ruiz; Thijssen, Karen L.; Kema, Ido P.; Neri, Christian; Oefner, Peter J.; Nollen, Ellen A. A.

    2012-01-01

    Toxicity of aggregation-prone proteins is thought to play an important role in aging and age-related neurological diseases like Parkinson and Alzheimer's diseases. Here, we identify tryptophan 2,3-dioxygenase (tdo-2), the first enzyme in the kynurenine pathway of tryptophan degradation, as a

  5. The association of sleep quality and insomnia with dietary intake of tryptophan and niacin

    NARCIS (Netherlands)

    Verster, J.; Fernstrand, A.; Bury, D.; Roth, T.; Garssen, J.

    2015-01-01

    Introduction: Dietary intake of tryptophan and niacin have been related to sleep. However, the sleep-promoting effects of these nutrients are still under investigation. The aim of the current study was to examine the relationship between daily dietary intake of tryptophan and niacin and sleep.

  6. Does acute tryptophan depletion affect peripheral serotonin metabolism in the intestine?

    NARCIS (Netherlands)

    Keszthelyi, D.; Troost, F.J.; Jonkers, D.M.; Donkelaar, van E.L.; Dekker, J.; Buurman, W.A.; Masclee, A.A.

    2012-01-01

    Background: Serotonin (5-hydroxytryptamine; 5-HT), a tryptophan metabolite, plays an important regulatory role in the human central nervous system and in the gastrointestinal tract. Acute tryptophan depletion (ATD) is currently the most widely established method to investigate 5-HT metabolism.

  7. Photophysics of tryptophan in H2O, D2O, and in nonaqueous solvents

    International Nuclear Information System (INIS)

    Gudgin, E.; Lopez-Delgado, R.; Ware, W.R.

    1983-01-01

    The fluorescence properties of tryptophan in water and deuterated water have been examined. Tryptophan molecules exhibit three distinct fluorescence lifetimes in water which become longer in deuterated water; the two shorter lifetimes are present below the pK of the amino group and the long lifetime appears as the pH is raised through this pK. The steady-state quenching of tryptophan fluorescence by hydrogen ion in the region of pH less than 3 shows a definite wavelength effect, consistent with less-pronounced quenching of the subnanosecond component whose emission maximum is at 330 nm. The Stern-Volmer plots show a marked curvature in the direction of decreasing Stern-Volmer constant as [H 3 O + ] increases. Deuterium ion also quenches tryptophan fluorescence at low pD. A kinetic scheme is proposed which reproduces both the steady-state and lifetime quenching results. Tryptophan in methanol or ethanol exhibits three fluorescence lifetimes; the relative percentage of the long component vs. the intermediate component can be varied by the addition of triethylamine or acid. In dimethyl sulfoxide, tryptophan and tryptophan deuterated at the amino and ring nirogen positions show identical behavior, both having the same decay parameters. These results are discussed in light of the theories which have recently been proposed to account for the several components in tryptophan fluorescence decay. Solvent interaction is suggested to play a critical role

  8. Residual stresses

    International Nuclear Information System (INIS)

    Macherauch, E.

    1978-01-01

    Residual stresses are stresses which exist in a material without the influence of external powers and moments. They come into existence when the volume of a material constantly changes its form as a consequence of mechanical, thermal, and/or chemical processes and is hindered by neighbouring volumes. Bodies with residual stress are in mechanical balance. These residual stresses can be manifested by means of all mechanical interventions disturbing this balance. Acoustical, optical, radiological, and magnetical methods involving material changes caused by residual stress can also serve for determining residual stress. Residual stresses have an ambivalent character. In technical practice, they are feared and liked at the same time. They cause trouble because they can be the cause for unexpected behaviour of construction elements. They are feared since they can cause failure, in the worst case with catastrophical consequences. They are appreciated, on the other hand, because, in many cases, they can contribute to improvements of the material behaviour under certain circumstances. But they are especially liked for their giving convenient and (this is most important) mostly uncontrollable explanations. For only in very few cases we have enough knowledge and possibilities for the objective evaluation of residual stresses. (orig.) [de

  9. The crystal structure of tryptophan hydroxylase with bound amino acid substrate

    DEFF Research Database (Denmark)

    Windahl, Michael Skovbo; Petersen, Charlotte Rode; Christensen, Hans Erik Mølager

    2008-01-01

    Tryptophan hydroxylase (TPH) is a mononuclear non-heme iron enzyme, which catalyzes the reaction between tryptophan, O2, and tetrahydrobiopterin (BH4) to produce 5-hydroxytryptophan and 4a-hydroxytetrahydrobiopterin. This is the first and rate-limiting step in the biosynthesis of the neurotransmi......Tryptophan hydroxylase (TPH) is a mononuclear non-heme iron enzyme, which catalyzes the reaction between tryptophan, O2, and tetrahydrobiopterin (BH4) to produce 5-hydroxytryptophan and 4a-hydroxytetrahydrobiopterin. This is the first and rate-limiting step in the biosynthesis...... acid hydroxylase with bound natural amino acid substrate. The iron coordination can be described as distorted trigonal bipyramidal coordination with His273, His278, and Glu318 (partially bidentate) and one imidazole as ligands. The tryptophan stacks against Pro269 with a distance of 3.9 Å between...

  10. Dissecting the Catalytic Mechanism of Betaine-Homocysteine S-Methyltransferase Using Intrinsic Tryptophan Fluorescence and Site-Directed Mutagenesis

    Energy Technology Data Exchange (ETDEWEB)

    Castro, C.; Gratson, A.A.; Evans, J.C.; Jiracek, J.; Collinsova, M.; Ludwig, M.L.; Garrow, T.A. (ASCR); (UIUC); (Michigan)

    2010-03-05

    Betaine-homocysteine S-methyltransferase (BHMT) is a zinc-dependent enzyme that catalyzes the transfer of a methyl group from glycine betaine (Bet) to homocysteine (Hcy) to form dimethylglycine (DMG) and methionine (Met). Previous studies in other laboratories have indicated that catalysis proceeds through the formation of a ternary complex, with a transition state mimicked by the inhibitor S-({delta}-carboxybutyl)-l-homocysteine (CBHcy). Using changes in intrinsic tryptophan fluorescence to determine the affinity of human BHMT for substrates, products, or CBHcy, we now demonstrate that the enzyme-substrate complex reaches its transition state through an ordered bi-bi mechanism in which Hcy is the first substrate to bind and Met is the last product released. Hcy, Met, and CBHcy bind to the enzyme to form binary complexes with K{sub d} values of 7.9, 6.9, and 0.28 {micro}M, respectively. Binary complexes with Bet and DMG cannot be detected with fluorescence as a probe, but Bet and DMG bind tightly to BHMT-Hcy to form ternary complexes with K{sub d} values of 1.1 and 0.73 {micro}M, respectively. Mutation of each of the seven tryptophan residues in human BHMT provides evidence that the enzyme undergoes two distinct conformational changes that are reflected in the fluorescence of the enzyme. The first is induced when Hcy binds, and the second, when Bet binds. As predicted by the crystal structure of BHMT, the amino acids Trp44 and Tyr160 are involved in binding Bet, and Glu159 in binding Hcy. Replacing these residues by site-directed mutagenesis significantly reduces the catalytic efficiency (V{sub max}/K{sub m}) of the enzyme. Replacing Tyr77 with Phe abolishes enzyme activity.

  11. Doxycycline induced photodamage to human neutrophils and tryptophan

    International Nuclear Information System (INIS)

    Sandberg, S.; Glette, J.; Hopen, G.; Solberg, C.O.

    1984-01-01

    Neutrophil function were studied following irradiation (340-380 nm) of the cells in the presence of 22 μM doxycycline. At increasing light fluence the locomotion, chemiluminescence and glucose oxidation (by the hexose monophosphate shunt) of the neutrophils steadily decreased. The photodamage increased with increasing preincubation temperature and time and was enhanced in D 2 O, reduced in azide and abolished in anaerobiosis. Superoxide dismutase, catalase or mannitol did not influence the photodamage. Photooxidation of tryptophan in the presence of doxycycline was increased 9-10-fold in D 2 O and nearly abolished in the presence of 0.25 mM NaN 3 , indicating that singlet oxygen is the most important reactive oxygen species in the doxycycline-induced photodamage. The results may explain some of the features of tetracycline-induced photosensitivity and why other authors have obtained diverging results when studying the influence of tetracyclines on neutrophil functions. (author)

  12. The tryptophan hydroxylase 1 (TPH1) gene, schizophrenia susceptibility, and suicidal behavior: a multi-centre case-control study and meta-analysis

    DEFF Research Database (Denmark)

    Saetre, Peter; Lundmark, Per; Wang, August

    2010-01-01

    Serotonin (5-hydroxytryptamin; 5-HT) alternations has since long been suspected in the pathophysiology of schizophrenia. Tryptophan hydroxylase (tryptophan 5-monooxygenase; TPH) is the rate-limiting enzyme in the biosynthesis of 5-HT, and sequence variation in intron 6 of the TPH1 gene has been...... associated with schizophrenia. The minor allele (A) of this polymorphism (A218C) is also more frequent in patients who have attempted suicide and individuals who died by suicide, than in healthy control individuals. In an attempt to replicate previous findings, five single nucleotide polymorphisms (SNPs......) were genotyped in 837 Scandinavian schizophrenia patients and 1,473 controls. Three SNPs spanning intron 6 and 7, including the A218C and A779C polymorphisms, were associated with schizophrenia susceptibility (P = 0.019). However there were no differences in allele frequencies of these loci between...

  13. Single molecule TPM analysis of the catalytic pentad mutants of Cre and Flp site-specific recombinases: contributions of the pentad residues to the pre-chemical steps of recombination

    Science.gov (United States)

    Fan, Hsiu-Fang; Cheng, Yong-Song; Ma, Chien-Hui; Jayaram, Makkuni

    2015-01-01

    Cre and Flp site-specific recombinase variants harboring point mutations at their conserved catalytic pentad positions were characterized using single molecule tethered particle motion (TPM) analysis. The findings reveal contributions of these amino acids to the pre-chemical steps of recombination. They suggest functional differences between positionally conserved residues in how they influence recombinase-target site association and formation of ‘non-productive’, ‘pre-synaptic’ and ‘synaptic’ complexes. The most striking difference between the two systems is noted for the single conserved lysine. The pentad residues in Cre enhance commitment to recombination by kinetically favoring the formation of pre-synaptic complexes. These residues in Flp serve a similar function by promoting Flp binding to target sites, reducing non-productive binding and/or enhancing the rate of assembly of synaptic complexes. Kinetic comparisons between Cre and Flp, and between their derivatives lacking the tyrosine nucleophile, are consistent with a stronger commitment to recombination in the Flp system. The effect of target site orientation (head-to-head or head-to-tail) on the TPM behavior of synapsed DNA molecules supports the selection of anti-parallel target site alignment prior to the chemical steps. The integrity of the synapse, whose establishment/stability is fostered by strand cleavage in the case of Flp but not Cre, appears to be compromised by the pentad mutations. PMID:25765648

  14. Role for tryptophan in regulation of protein synthesis in porcine muscle

    International Nuclear Information System (INIS)

    Lin, F.D.; Smith, T.K.; Bayley, H.S.

    1988-01-01

    Experiments were conducted to determine the effect of varying concentrations of dietary tryptophan on growth rate and protein synthesis in edible muscle tissues of growing swine. A total of 45 immature swine (initial weight approximately 24 kg) were fed corn-gelatin diets containing 0.5 (n = 8), 0.8 (n = 10), 1.3 (n = 10), 1.5 (n = 7) or 2.0 (n = 10) g tryptophan/kg diet for 35 d. Animals fed 0.5 and 0.8 g tryptophan/kg grew more slowly, consumed less feed and had a lower efficiency of feed utilization than animals fed higher concentrations of tryptophan. Thirty similar animals were used in a second experiment. Diets containing 0.5, 0.8, 1.0, 1.5 or 2.0 g tryptophan/kg diet (n = 6) were fed for 14 d, after which all animals were killed and samples were taken of longissimus dorsi, triceps brachii and biceps femoris. Protein synthetic activity was determined by monitoring the incorporation of [ 14 C]phenylalanine into protein in vitro. There was no significant difference in synthetic activity between different muscle types. There was no effect of diet on the activity of the muscle soluble protein fraction. The activity of the muscle ribosomal fraction, however, was positively correlated with increasing concentrations of dietary tryptophan. It was concluded that tryptophan has the potential to regulate muscle protein synthesis in a manner beyond serving simply as a component of protein

  15. Solid residues

    International Nuclear Information System (INIS)

    Mulder, E.; Duin, P.J. van; Grootenboer, G.J.

    1995-01-01

    A summary is presented of the many investigations that have been done on solid residues of atmospheric fluid bed combustion (AFBC). These residues are bed ash, cyclone ash and bag filter ash. Physical and chemical properties are discussed and then the various uses of residues (in fillers, bricks, gravel, and for recovery of aluminium) are summarised. Toxicological properties of fly ash and stack ash are discussed as are risks of pneumoconiosis for workers handling fly ash, and contamination of water by ashes. On the basis of present information it is concluded that risks to public health from exposure to emissions of coal fly ash from AFBC appear small or negligible as are health risk to workers in the coal fly ash processing industry. 35 refs., 5 figs., 12 tabs

  16. Single residue mutation in active site of serine acetyltransferase isoform 3 from Entamoeba histolytica assists in partial regaining of feedback inhibition by cysteine.

    Directory of Open Access Journals (Sweden)

    Sudhir Kumar

    Full Text Available The cysteine biosynthetic pathway is essential for survival of the protist pathogen Entamoeba histolytica, and functions by producing cysteine for countering oxidative attack during infection in human hosts. Serine acetyltransferase (SAT and O-acetylserine sulfhydrylase (OASS are involved in cysteine biosynthesis and are present in three isoforms each. While EhSAT1 and EhSAT2 are feedback inhibited by end product cysteine, EhSAT3 is nearly insensitive to such inhibition. The active site residues of EhSAT1 and of EhSAT3 are identical except for position 208, which is a histidine residue in EhSAT1 and a serine residue in EhSAT3. A combination of comparative modeling, multiple molecular dynamics simulations and free energy calculation studies showed a difference in binding energies of native EhSAT3 and of a S208H-EhSAT3 mutant for cysteine. Mutants have also been generated in vitro, replacing serine with histidine at position 208 in EhSAT3 and replacing histidine 208 with serine in EhSAT1. These mutants showed decreased affinity for substrate serine, as indicated by K(m, compared to the native enzymes. Inhibition kinetics in the presence of physiological concentrations of serine show that IC50 of EhSAT1 increases by about 18 folds from 9.59 µM for native to 169.88 µM for H208S-EhSAT1 mutant. Similar measurements with EhSAT3 confirm it to be insensitive to cysteine inhibition while its mutant (S208H-EhSAT3 shows a gain of cysteine inhibition by 36% and the IC50 of 3.5 mM. Histidine 208 appears to be one of the important residues that distinguish the serine substrate from the cysteine inhibitor.

  17. Research of nitroxynil residues in bovine milk following a single administration in the dry period by ultra-performance liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Claudia Chirollo

    2013-10-01

    Full Text Available Nitroxynil (NIT is a halogenated phenol used to control fascioliasis in cattle and sheep. The Commission Regulation EU No 37/2010 has established maximum residue limits for NIT in bovine and ovine muscle (400 μg kg−1, fat (200 μg kg−1, liver (20 μg kg−1 and kidney (400 μg kg−1, and more recently in bovine and ovine milk (20 μg kg−1. Thirty-five pregnant dairy cows were treated in this study with nitroxynil (340 mg/mL solution for injection at the recommended dose of 10 mg/kg body weight at the start of the dry period, i.e. 53 to 74 days before the expected calving. Calving occurred between 43 days and 79 days after treatment. The concentrations of NIT in the milk were monitored for up to 120 days after calving. NIT residues were extracted using acetonitrile; magnesium sulfate and sodium chloride were added to induce liquid-liquid partitioning and purified by dispersive solid phase extraction for clean-up. NIT was detected by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS in negative ionization mode. The highest concentrations of this drug were found in two animals at the first milking, 48 and 53 day post treatment with levels of 362 and 657 μg kg–1, respectively. NIT residues were below the limit of detection of the method (0.24 μg/kg–1 between 67 and 106 day post-treatment. Following calving, residues rapidly depleted in animals and were non-detectable from 10 to 38 days post-calving. In particular, in all animals milk resulted compliant (<20 μg/kg−1 three days post partum.

  18. The influence of tryptophan on gluconeogenesis in the perfused liver of irradiated rats

    International Nuclear Information System (INIS)

    Borovikova, G.V.; Mashkova, N.Yu.; Dokshina, G.A.

    1985-01-01

    The liver isolated at different times after exposure to 7 Gy radiation responded in a different way to the effect of tryptophan (0.75 g/l) used as a gluconeogenesis inhibitor. While 24 h after irradiation of the addition of tryptophan inhibited gluconeogenesis from circulating exogenous amino acids, in 3 days, on the contrary, gluconeogenesis in the liver of donors was enhanced. It is suggested that these effects of tryptophan are associated with different functional status of the liver during the postirradiation observation period

  19. Acetyl coenzyme A synthetase is acetylated on multiple lysine residues by a protein acetyltransferase with a single Gcn5-type N-acetyltransferase (GNAT) domain in Saccharopolyspora erythraea.

    Science.gov (United States)

    You, Di; Yao, Li-Li; Huang, Dan; Escalante-Semerena, Jorge C; Ye, Bang-Ce

    2014-09-01

    Reversible lysine acetylation (RLA) is used by cells of all domains of life to modulate protein function. To date, bacterial acetylation/deacetylation systems have been studied in a few bacteria (e.g., Salmonella enterica, Bacillus subtilis, Escherichia coli, Erwinia amylovora, Mycobacterium tuberculosis, and Geobacillus kaustophilus), but little is known about RLA in antibiotic-producing actinomycetes. Here, we identify the Gcn5-like protein acetyltransferase AcuA of Saccharopolyspora erythraea (SacAcuA, SACE_5148) as the enzyme responsible for the acetylation of the AMP-forming acetyl coenzyme A synthetase (SacAcsA, SACE_2375). Acetylated SacAcsA was deacetylated by a sirtuin-type NAD(+)-dependent consuming deacetylase (SacSrtN, SACE_3798). In vitro acetylation/deacetylation of SacAcsA enzyme was studied by Western blotting, and acetylation of lysine residues Lys(237), Lys(380), Lys(611), and Lys(628) was confirmed by mass spectrometry. In a strain devoid of SacAcuA, none of the above-mentioned Lys residues of SacAcsA was acetylated. To our knowledge, the ability of SacAcuA to acetylate multiple Lys residues is unique among AcuA-type acetyltransferases. Results from site-specific mutagenesis experiments showed that the activity of SacAcsA was controlled by lysine acetylation. Lastly, immunoprecipitation data showed that in vivo acetylation of SacAcsA was influenced by glucose and acetate availability. These results suggested that reversible acetylation may also be a conserved regulatory posttranslational modification strategy in antibiotic-producing actinomycetes. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  20. FLIM-FRET image analysis of tryptophan in prostate cancer cells

    Science.gov (United States)

    Periasamy, Ammasi; Alam, Shagufta R.; Svindrych, Zdenek; Wallrabe, Horst

    2017-07-01

    A region of interest (ROI) based quantitative FLIM-FRET image analysis is developed to quantitate the autofluorescence signals of the essential amino acid tryptophan as a biomarker to investigate the metabolism in prostate cancer cells.

  1. Acute tryptophan depletion dose dependently impairs object memory in serotonin transporter knockout rats

    NARCIS (Netherlands)

    Olivier, J D A; Jans, L A W; Korte-Bouws, G A H; Korte, S M; Deen, P M T; Cools, A R; Ellenbroek, B A; Blokland, A

    2008-01-01

    RATIONALE: Acute tryptophan depletion (ATD) transiently lowers central serotonin levels and can induce depressive mood states and cognitive defects. Previous studies have shown that ATD impairs object recognition in rats. OBJECTIVES: As individual differences exist in central serotonin

  2. Immunosuppressive Tryptophan Catabolism and Gut Mucosal Dysfunction Following Early HIV Infection

    NARCIS (Netherlands)

    Jenabian, Mohammad-Ali; El-Far, Mohamed; Vyboh, Kishanda; Kema, Ido; Costiniuk, Cecilia T.; Thomas, Rejean; Baril, Jean-Guy; LeBlanc, Roger; Kanagaratham, Cynthia; Radzioch, Danuta; Allam, Ossama; Ahmad, Ali; Lebouche, Bertrand; Tremblay, Cecile; Ancuta, Petronela; Routy, Jean-Pierre

    2015-01-01

    Background. Tryptophan (Trp) catabolism into kynurenine (Kyn) contributes to immune dysfunction in chronic human immunodeficiency virus (HIV) infection. To better define the relationship between Trp catabolism, inflammation, gut mucosal dysfunction, and the role of early antiretroviral therapy

  3. Tryptophan Oxidative Metabolism Catalyzed by : A Thermophile Isolated from Kuwait Soil Contaminated with Petroleum Hydrocarbons

    Directory of Open Access Journals (Sweden)

    Jassim M. Al-Hassan

    2011-01-01

    Full Text Available Tryptophan metabolism has been extensively studied in humans as well as in soil. Its metabolism takes place mainly through kynurenine pathway yielding hydroxylated, deaminated and many other products of physiological significance. However, tryptophan metabolism has not been studied in an isolated thermophilic bacterium. Geobacillus stearothermophilus is a local thermophile isolated from Kuwait desert soil contaminated with petroleum hydrocarbons. The bacterium grows well at 65 °C in 0.05 M phosphate buffer (pH 7, when supplied with organic compounds as a carbon source and has a good potential for transformation of steroids and related molecules. In the present study, we used tryptophan ethyl ester as a carbon source for the bacterium to study the catabolism of the amino acid at pH 5 and pH 7. In this endeavor, we have resolved twenty one transformation products of tryptophan by GC/LC and have identified them through their mass spectral fragmentation.

  4. Picosecond Fluorescence Dynamics of Tryptophan and 5-Fluorotryptophan in Monellin : Slow Water-Protein Relaxation Unmasked

    NARCIS (Netherlands)

    Xu, Jianhua; Chen, Binbin; Callis, Patrik Robert; Muiño, Pedro L; Rozeboom, Henriette J; Broos, Jaap; Toptygin, Dmitri; Brand, Ludwig; Knutson, Jay R

    2015-01-01

    Time Dependent Fluorescence Stokes (emission wavelength) Shifts (TDFSS) from tryptophan (Trp) following sub-picosecond excitation are increasingly used to investigate protein dynamics, most recently enabling active research interest into water dynamics near the surface of proteins. Unlike many

  5. Linoleic acid, thymine, and tryptophan radiosensitization by protoporphyrin in presence of oxygene

    International Nuclear Information System (INIS)

    Champel, P.; Mignot, M.A.; Pillement, B.; Fontenil, L.; Rocquet, G.

    Sensitizing effect induced by protoporphyrin, an active molecule in photooxidation is studied. Studied substances are tryptophan, thymine, linoleic acid, each component representing one of the great groups of biological components, nucleic acid, proteins, lipids [fr

  6. Residues at a Single Site Differentiate Animal Cryptochromes from Cyclobutane Pyrimidine Dimer Photolyases by Affecting the Proteins' Preferences for Reduced FAD.

    Science.gov (United States)

    Xu, Lei; Wen, Bin; Wang, Yuan; Tian, Changqing; Wu, Mingcai; Zhu, Guoping

    2017-06-19

    Cryptochromes (CRYs) and photolyases belong to the cryptochrome/photolyase family (CPF). Reduced FAD is essential for photolyases to photorepair UV-induced cyclobutane pyrimidine dimers (CPDs) or 6-4 photoproducts in DNA. In Drosophila CRY (dCRY, a type I animal CRY), FAD is converted to the anionic radical but not to the reduced state upon illumination, which might induce a conformational change in the protein to relay the light signal downstream. To explore the foundation of these differences, multiple sequence alignment of 650 CPF protein sequences was performed. We identified a site facing FAD (Ala377 in Escherichia coli CPD photolyase and Val415 in dCRY), hereafter referred to as "site 377", that was distinctly conserved across these sequences: CPD photolyases often had Ala, Ser, or Asn at this site, whereas animal CRYs had Ile, Leu, or Val. The binding affinity for reduced FAD, but not the photorepair activity of E. coli photolyase, was dramatically impaired when replacing Ala377 with any of the three CRY residues. Conversely, in V415S and V415N mutants of dCRY, FAD was photoreduced to its fully reduced state after prolonged illumination, and light-dependent conformational changes of these mutants were severely inhibited. We speculate that the residues at site 377 play a key role in the different preferences of CPF proteins for reduced FAD, which differentiate animal CRYs from CPD photolyases. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. High-throughput metabolic profiling of diverse green Coffea arabica beans identified tryptophan as a universal discrimination factor for immature beans.

    Science.gov (United States)

    Setoyama, Daiki; Iwasa, Keiko; Seta, Harumichi; Shimizu, Hiroaki; Fujimura, Yoshinori; Miura, Daisuke; Wariishi, Hiroyuki; Nagai, Chifumi; Nakahara, Koichi

    2013-01-01

    The maturity of green coffee beans is the most influential determinant of the quality and flavor of the resultant coffee beverage. However, the chemical compounds that can be used to discriminate the maturity of the beans remain uncharacterized. We herein analyzed four distinct stages of maturity (immature, semi-mature, mature and overripe) of nine different varieties of green Coffea arabica beans hand-harvested from a single experimental field in Hawaii. After developing a high-throughput experimental system for sample preparation and liquid chromatography-mass spectrometry (LC-MS) measurement, we applied metabolic profiling, integrated with chemometric techniques, to explore the relationship between the metabolome and maturity of the sample in a non-biased way. For the multivariate statistical analyses, a partial least square (PLS) regression model was successfully created, which allowed us to accurately predict the maturity of the beans based on the metabolomic information. As a result, tryptophan was identified to be the best contributor to the regression model; the relative MS intensity of tryptophan was higher in immature beans than in those after the semi-mature stages in all arabica varieties investigated, demonstrating a universal discrimination factor for diverse arabica beans. Therefore, typtophan, either alone or together with other metabolites, may be utilized for traders as an assessment standard when purchasing qualified trading green arabica bean products. Furthermore, our results suggest that the tryptophan metabolism may be tightly linked to the development of coffee cherries and/or beans.

  8. Kinetic tritium isotopic effects in the position 2 for 5'-hydroxy-L-tryptophane

    International Nuclear Information System (INIS)

    Boroda, E.; Kanska, M.

    2006-01-01

    Tryptophanase converts 5'-hydroxy-L-tryptophane to pyrogronic acid and ammonia, however there are known conditions for the reversed reaction. Mechanism of the processes are not known till now. Kinetic isotopic effect (KIE) permits finding the rate determining stage in the multistage process. In presented communication, 5'-hydroxy-[2- 3 H]-L-tryptophane was synthesized and the KIE in the room temperature determined for different reaction stages

  9. Syntheses and Self-assembling Behaviors of Pentagonal Conjugates of Tryptophane Zipper-Forming Peptide

    Directory of Open Access Journals (Sweden)

    Nobuo Kimizuka

    2011-08-01

    Full Text Available Pentagonal conjugates of tryptophane zipper-forming peptide (CKTWTWTE with a pentaazacyclopentadecane core (Pentagonal-Gly-Trpzip and Pentagonal-Ala-Trpzip were synthesized and their self-assembling behaviors were investigated in water. Pentagonal-Gly-Trpzip self-assembled into nanofibers with the width of about 5 nm in neutral water (pH 7 via formation of tryptophane zipper, which irreversibly converted to nanoribbons by heating. In contrast, Pentagonal-Ala-Trpzip formed irregular aggregates in water.

  10. Changes of intermediary taurine and tryptophan metabolism after combined radiation-thermal injury

    International Nuclear Information System (INIS)

    Konnova, L.A.; Novoselova, G.S.

    1986-01-01

    The dynamics of changes of the taurine and tryptophane concentration in blood serum of rats has been studied during 30 days after 3b degree burn of 15% of body surface after total even exposure to radiation in doses of 3 and 6 Gy, and after combined radiation thermal injury. Combined radiation-thermal injury was found to be characterized by reduced concentration of taurine but an increase of the tryptophane level from the second-third day after the injury

  11. GPR142 Controls Tryptophan-Induced Insulin and Incretin Hormone Secretion to Improve Glucose Metabolism

    OpenAIRE

    Lin, Hua V.; Efanov, Alexander M.; Fang, Xiankang; Beavers, Lisa S.; Wang, Xuesong; Wang, Jingru; Gonzalez Valcarcel, Isabel C.; Ma, Tianwei

    2016-01-01

    GPR142, a putative amino acid receptor, is expressed in pancreatic islets and the gastrointestinal tract, but the ligand affinity and physiological role of this receptor remain obscure. In this study, we show that in addition to L-Tryptophan, GPR142 signaling is also activated by L-Phenylalanine but not by other naturally occurring amino acids. Furthermore, we show that Tryptophan and a synthetic GPR142 agonist increase insulin and incretin hormones and improve glucose disposal in mice in a G...

  12. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  13. Removing the by-products acetic acid and NH4+ from the l-tryptophan broth by vacuum thin film evaporation during l-tryptophan production

    Directory of Open Access Journals (Sweden)

    Qingyang Xu

    2018-05-01

    Full Text Available Background: During l-tryptophan production by Escherichia coli, the by-products, acetic acid and NH4+, accumulate in the fermentation broth, resulting in inhibited cell growth and activity and decreased l-tryptophan production. To improve the l-tryptophan yield and glucose conversion rate, acetic acid and NH4+ were removed under low-temperature vacuum conditions by vacuum scraper concentrator evaporation; the fermentation broth after evaporation was pressed into another fermenter to continue fermentation. To increase the volatilisation rate of acetic acid and NH4+ and reduce damage to bacteria during evaporation, different vacuum evaporation conditions were studied. Results: The optimum operating conditions were as follows: vacuum degree, 720 mm Hg; concentration ratio, 10%; temperature, 60°C; and feeding rate, 300 mL/min. The biomass yield of the control fermentation (CF and fermentation by vacuum evaporation (VEF broths was 55.1 g/L and 58.3 g/L at 38 h, respectively, (an increase of 5.8%; the living biomass yield increased from 8.9 (CF to 10.2 pF (VEF; an increase of 14.6%. l-tryptophan production increased from 50.2 g/L (CF to 60.2 g/L (VEF (an increase of 19.9%, and glucose conversion increased from 18.2% (CF to 19.5% (VEF; an increase of 7.1%. The acetic acid concentrations were 2.74 g/L and 6.70 g/L, and the NH4+ concentrations were 85.3 mmol/L and 130.9 mmol/L in VEF and CF broths, respectively. Conclusions: The acetic acid and NH4+ in the fermentation broth were quickly removed using the vacuum scraper concentrator, which reduced bacterial inhibition, enhanced bacterial activity, and improved the production of l-tryptophan and glucose conversion rate.How to cite: Xu Q, Bai F, Chen N, et al. Removing the by-products acetic acid and NH4+ from the l-tryptophan broth by vacuum thin film evaporation during l-tryptophan production. Electron J Biotechnol 2018; 33. https://doi.org/10.1016/j.ejbt.2018.04.003. Keywords: Acetic acid

  14. Structural Insights into l-Tryptophan Dehydrogenase from a Photoautotrophic Cyanobacterium, Nostoc punctiforme.

    Science.gov (United States)

    Wakamatsu, Taisuke; Sakuraba, Haruhiko; Kitamura, Megumi; Hakumai, Yuichi; Fukui, Kenji; Ohnishi, Kouhei; Ashiuchi, Makoto; Ohshima, Toshihisa

    2017-01-15

    l-Tryptophan dehydrogenase from Nostoc punctiforme NIES-2108 (NpTrpDH), despite exhibiting high amino acid sequence identity (>30%)/homology (>50%) with NAD(P) + -dependent l-Glu/l-Leu/l-Phe/l-Val dehydrogenases, exclusively catalyzes reversible oxidative deamination of l-Trp to 3-indolepyruvate in the presence of NAD + Here, we determined the crystal structure of the apo form of NpTrpDH. The structure of the NpTrpDH monomer, which exhibited high similarity to that of l-Glu/l-Leu/l-Phe dehydrogenases, consisted of a substrate-binding domain (domain I, residues 3 to 133 and 328 to 343) and an NAD + /NADH-binding domain (domain II, residues 142 to 327) separated by a deep cleft. The apo-NpTrpDH existed in an open conformation, where domains I and II were apart from each other. The subunits dimerized themselves mainly through interactions between amino acid residues around the β-1 strand of each subunit, as was observed in the case of l-Phe dehydrogenase. The binding site for the substrate l-Trp was predicted by a molecular docking simulation and validated by site-directed mutagenesis. Several hydrophobic residues, which were located in the active site of NpTrpDH and possibly interacted with the side chain of the substrate l-Trp, were arranged similarly to that found in l-Leu/l-Phe dehydrogenases but fairly different from that of an l-Glu dehydrogenase. Our crystal structure revealed that Met-40, Ala-69, Ile-74, Ile-110, Leu-288, Ile-289, and Tyr-292 formed a hydrophobic cluster around the active site. The results of the site-directed mutagenesis experiments suggested that the hydrophobic cluster plays critical roles in protein folding, l-Trp recognition, and catalysis. Our results provide critical information for further characterization and engineering of this enzyme. In this study, we determined the three-dimensional structure of l-Trp dehydrogenase, analyzed its various site-directed substitution mutants at residues located in the active site, and obtained the

  15. Flexible Enantioselectivity of Tryptophanase Attributable to Benzene Ring in Heterocyclic Moiety of D-Tryptophan

    Directory of Open Access Journals (Sweden)

    Akihiko Shimada

    2012-05-01

    Full Text Available The invariance principle of enzyme enantioselectivity must be absolute because it is absolutely essential to the homochiral biological world. Most enzymes are strictly enantioselective, and tryptophanase is one of the enzymes with extreme absolute enantioselectivity for L-tryptophan. Contrary to conventional knowledge about the principle, tryptophanase becomes flexible to catalyze D-tryptophan in the presence of diammonium hydrogenphosphate. Since D-amino acids are ordinarily inert or function as inhibitors even though they are bound to the active site, the inhibition behavior of D-tryptophan and several inhibitors involved in this process was examined in terms of kinetics to explain the reason for this flexible enantioselectivity in the presence of diammonium hydrogenphosphate. Diammonium hydrogenphosphate gave tryptophanase a small conformational change so that D-tryptophan could work as a substrate. As opposed to other D-amino acids, D-tryptophan is a very bulky amino acid with a benzene ring in its heterocyclic moiety, and so we suggest that this structural feature makes the catalysis of D-tryptophan degradation possible, consequently leading to the flexible enantioselectivity. The present results not only help to understand the mechanism of enzyme enantioselectivity, but also shed light on the origin of homochirality.

  16. Influence of tryptophan and related compounds on ergot alkaloid formation in Claviceps purpurea (FR.) Tul.

    Science.gov (United States)

    Erge, D; Schumann, B; Gröger, D

    1984-01-01

    L-Tryptophan did not exert any influence on peptide alkaloid formation in an ergotamine and in an ergosine-accumulating C. purpurea strain. A different picture was observed in a series of related C. purpurea strains. Tryptophan showed a slight stimulatory effect on the ergotoxine producer Pepty 695/S. A blocked mutant of it, designated as Pepty 695/ch which was able to accumulate secoclavines gave similar results. In a high-yielding elymoclavine strain Pepty 695/e, the progeny of the former one, tryptophan up to a concentration of 25 mM stimulated remarkably clavine biosynthesis. Furthermore, tryptophan could overcome the block of synthesis by inorganic phosphate. Increased specific activities of chanoclavine cyclase but not DMAT synthetase were observed in cultures of strain Pepty 695/e supplemented with tryptophan. 5-Methyltryptophan and bioisosteres of tryptophan were ineffective in alkaloid stimulation. These results are compared with those obtained with the grass ergot strain SD 58 and discussed with the relation to other induction phenomena.

  17. Delaying aging and the aging-associated decline in protein homeostasis by inhibition of tryptophan degradation

    Science.gov (United States)

    van der Goot, Annemieke T.; Zhu, Wentao; Vázquez-Manrique, Rafael P.; Seinstra, Renée I.; Dettmer, Katja; Michels, Helen; Farina, Francesca; Krijnen, Jasper; Melki, Ronald; Buijsman, Rogier C.; Ruiz Silva, Mariana; Thijssen, Karen L.; Kema, Ido P.; Neri, Christian; Oefner, Peter J.; Nollen, Ellen A. A.

    2012-01-01

    Toxicity of aggregation-prone proteins is thought to play an important role in aging and age-related neurological diseases like Parkinson and Alzheimer’s diseases. Here, we identify tryptophan 2,3-dioxygenase (tdo-2), the first enzyme in the kynurenine pathway of tryptophan degradation, as a metabolic regulator of age-related α-synuclein toxicity in a Caenorhabditis elegans model. Depletion of tdo-2 also suppresses toxicity of other heterologous aggregation-prone proteins, including amyloid-β and polyglutamine proteins, and endogenous metastable proteins that are sensors of normal protein homeostasis. This finding suggests that tdo-2 functions as a general regulator of protein homeostasis. Analysis of metabolite levels in C. elegans strains with mutations in enzymes that act downstream of tdo-2 indicates that this suppression of toxicity is independent of downstream metabolites in the kynurenine pathway. Depletion of tdo-2 increases tryptophan levels, and feeding worms with extra l-tryptophan also suppresses toxicity, suggesting that tdo-2 regulates proteotoxicity through tryptophan. Depletion of tdo-2 extends lifespan in these worms. Together, these results implicate tdo-2 as a metabolic switch of age-related protein homeostasis and lifespan. With TDO and Indoleamine 2,3-dioxygenase as evolutionarily conserved human orthologs of TDO-2, intervening with tryptophan metabolism may offer avenues to reducing proteotoxicity in aging and age-related diseases. PMID:22927396

  18. Role of decreased Plasma Tryptophan in memory deficits observed in Type-I diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.; Tabassum, S.; Haider, S. [University of Karachi (Pakistan). Dept. of Biochemistry

    2013-01-15

    Objective: To investigate the relationship between plasma tryptophan and the occurrence of memory dysfunctions in male and female type 1 diabetics. Methods: The case-control study was conducted at two urban healthcare facilities in Karachi from January to June 2009, and comprised 100 diabetic subjects of among whom were 50 men and 50 women. The controls were also similar in number and gender. A questionnaire was used to evaluate the memory impairment in the subjects. Plasma tryptophan was determined by high performance liquid chromatography with ultra-violet method. Students t-test was used to analyse tryptophan data. Results: There was considerable memory impairment in the cases (n=40) compared to the controls (n=5). Results also showed a significant (p<0.01) decrease in plasma tryptophan levels in both male and female diabetic patients. Conclusions: Diabetic subjects exhibited occurrence of memory impairment with concomitant decline in plasma tryptophan levels. The findings indicate that decreased brain uptake of tryptophan and lowered brain 5-hydroxytryptamine levels may be responsible for the memory deficits seen in diabetics. (author)

  19. Role of decreased Plasma Tryptophan in memory deficits observed in Type-I diabetes

    International Nuclear Information System (INIS)

    Ahmad, S.; Tabassum, S.; Haider, S.

    2013-01-01

    Objective: To investigate the relationship between plasma tryptophan and the occurrence of memory dysfunctions in male and female type 1 diabetics. Methods: The case-control study was conducted at two urban healthcare facilities in Karachi from January to June 2009, and comprised 100 diabetic subjects of among whom were 50 men and 50 women. The controls were also similar in number and gender. A questionnaire was used to evaluate the memory impairment in the subjects. Plasma tryptophan was determined by high performance liquid chromatography with ultra-violet method. Students t-test was used to analyse tryptophan data. Results: There was considerable memory impairment in the cases (n=40) compared to the controls (n=5). Results also showed a significant (p<0.01) decrease in plasma tryptophan levels in both male and female diabetic patients. Conclusions: Diabetic subjects exhibited occurrence of memory impairment with concomitant decline in plasma tryptophan levels. The findings indicate that decreased brain uptake of tryptophan and lowered brain 5-hydroxytryptamine levels may be responsible for the memory deficits seen in diabetics. (author)

  20. Acute hyponatremia after cardioplegia by histidine-tryptophane-ketoglutarate – a retrospective study

    Directory of Open Access Journals (Sweden)

    Lindner Gregor

    2012-06-01

    Full Text Available Abstract Background Hyponatremia is the most common electrolyte disorder in hospitalized patients and is known to be associated with increased mortality. The administration of antegrade single-shot, up to two liters, histidine-tryptophane-ketoglutarate (HTK solution for adequate electromechanical cardiac arrest and myocardial preservation during minimally invasive aortic valve replacement (MIAVR is a standard procedure. We aimed to determine the impact of HTK infusion on electrolyte and acid–base balance. Methods In this retrospective analysis we reviewed data on patient characteristics, type of surgery, arterial blood gas analysis during surgery and intra-/postoperative laboratory results of patients receiving surgery for MIAVR at a large tertiary care university hospital. Results A total of 25 patients were included in the study. All patients were normonatremic at start of surgery. All patients developed hyponatremia after administration of HTK solution with a significant drop of serum sodium of 15 mmol/L (p  Conclusions Acute hyponatremia during cardioplegia with HTK solution is isotonic and should probably not be corrected without presence of hypotonicity as confirmed by measurement of serum osmolality.

  1. Serum stabilities of short tryptophan- and arginine-rich antimicrobial peptide analogs.

    Directory of Open Access Journals (Sweden)

    Leonard T Nguyen

    2010-09-01

    Full Text Available Several short antimicrobial peptides that are rich in tryptophan and arginine residues were designed with a series of simple modifications such as end capping and cyclization. The two sets of hexapeptides are based on the Trp- and Arg-rich primary sequences from the "antimicrobial centre" of bovine lactoferricin as well as an antimicrobial sequence obtained through the screening of a hexapeptide combinatorial library.HPLC, mass spectrometry and antimicrobial assays were carried out to explore the consequences of the modifications on the serum stability and microbicidal activity of the peptides. The results show that C-terminal amidation increases the antimicrobial activity but that it makes little difference to its proteolytic degradation in human serum. On the other hand, N-terminal acetylation decreases the peptide activities but significantly increases their protease resistance. Peptide cyclization of the hexameric peptides was found to be highly effective for both serum stability and antimicrobial activity. However the two cyclization strategies employed have different effects, with disulfide cyclization resulting in more active peptides while backbone cyclization results in more proteolytically stable peptides. However, the benefit of backbone cyclization did not extend to longer 11-mer peptides derived from the same region of lactoferricin. Mass spectrometry data support the serum stability assay results and allowed us to determine preferred proteolysis sites in the peptides. Furthermore, isothermal titration calorimetry experiments showed that the peptides all had weak interactions with albumin, the most abundant protein in human serum.Taken together, the results provide insight into the behavior of the peptides in human serum and will therefore aid in advancing antimicrobial peptide design towards systemic applications.

  2. Antitumour agents as inhibitors of tryptophan 2,3-dioxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Pantouris, Georgios; Mowat, Christopher G., E-mail: C.G.Mowat@ed.ac.uk

    2014-01-03

    Highlights: •∼2800 National Cancer Institute USA compounds have been screened as potential inhibitors of TDO and/or IDO. •Seven compounds with anti-tumour properties have been identified as potent inhibitors. •NSC 36398 (taxifolin, dihydroquercetin) is selective for TDO with a K{sub i} of 16 M. •This may help further our understanding of the role of TDO in cancer. -- Abstract: The involvement of tryptophan 2,3-dioxygenase (TDO) in cancer biology has recently been described, with the enzyme playing an immunomodulatory role, suppressing antitumour immune responses and promoting tumour cell survival and proliferation. This finding reinforces the need for specific inhibitors of TDO that may potentially be developed for therapeutic use. In this work we have screened ∼2800 compounds from the library of the National Cancer Institute USA and identified seven potent inhibitors of TDO with inhibition constants in the nanomolar or low micromolar range. All seven have antitumour properties, killing various cancer cell lines. For comparison, the inhibition potencies of these compounds were tested against IDO and their inhibition constants are reported. Interestingly, this work reveals that NSC 36398 (dihydroquercetin, taxifolin), with an in vitro inhibition constant of ∼16 μM, is the first TDO-selective inhibitor reported.

  3. B-ALL minimal residual disease flow cytometry: an application of a novel method for optimization of a single-tube model.

    Science.gov (United States)

    Shaver, Aaron C; Greig, Bruce W; Mosse, Claudio A; Seegmiller, Adam C

    2015-05-01

    Optimizing a clinical flow cytometry panel can be a subjective process dependent on experience. We develop a quantitative method to make this process more rigorous and apply it to B lymphoblastic leukemia/lymphoma (B-ALL) minimal residual disease (MRD) testing. We retrospectively analyzed our existing three-tube, seven-color B-ALL MRD panel and used our novel method to develop an optimized one-tube, eight-color panel, which was tested prospectively. The optimized one-tube, eight-color panel resulted in greater efficiency of time and resources with no loss in diagnostic power. Constructing a flow cytometry panel using a rigorous, objective, quantitative method permits optimization and avoids problems of interdependence and redundancy in a large, multiantigen panel. Copyright© by the American Society for Clinical Pathology.

  4. Proton affinity of the histidine-tryptophan cluster motif from the influenza A virus from ab initio molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bankura, Arindam; Klein, Michael L.; Carnevale, Vincenzo, E-mail: vincenzo.carnevale@temple.edu

    2013-08-30

    Highlights: • The estimated pK{sub a} is in agreement with the experimental one. • The affinity for protons is similar to that of a histidine residue in aqueous solution. • The electrostatic environment is responsible for the stabilization of the charged imidazolium moiety. - Abstract: Ab initio molecular dynamics calculations have been used to compare and contrast the deprotonation reaction of a histidine residue in aqueous solution with the situation arising in a histidine-tryptophan cluster. The latter is used as a model of the proton storage unit present in the pore of the M2 proton conducting ion channel. We compute potentials of mean force for the dissociation of a proton from the Nδ and N∊ positions of the imidazole group to estimate the pK{sub a}s. Anticipating our results, we will see that the estimated pK{sub a} for the first protonation event of the M2 channel is in good agreement with experimental estimates. Surprisingly, despite the fact that the histidine is partially desolvated in the M2 channel, the affinity for protons is similar to that of a histidine in aqueous solution. Importantly, the electrostatic environment provided by the indoles is responsible for the stabilization of the charged imidazolium.

  5. Photoinduced Intramolecular Tryptophan Oxidation and Excited-State Behavior of [Re(L-AA)(CO)3(r-diimine)] þ (L = Pyridine or Imidazole, AA = Tryptophan, Tyrosine, Phenylalanine)

    Czech Academy of Sciences Publication Activity Database

    Blanco-Rodríguez, A. M.; Towrie, M.; Sýkora, Jan; Záliš, Stanislav; Vlček, Antonín

    2011-01-01

    Roč. 50, č. 13 (2011), s. 6122-6134 ISSN 0020-1669 R&D Projects: GA MŠk(CZ) LD11082 Institutional research plan: CEZ:AV0Z40400503 Keywords : tryptophan * tyrosine * phenylalanine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.601, year: 2011

  6. A KAS2 cDNA complements the phenotypes of the Arabidopsis fab1 mutant that differs in a single residue bordering the substrate binding pocket

    DEFF Research Database (Denmark)

    Carlsson, A.S.; LaBrie, S.T.; Kinney, A.J.

    2002-01-01

    The fab1 mutant of Arabidopsis is partially deficient in activity of ß-ketoacyl-[acyl carrier protein] synthase II (KAS II). This defect results in increased levels of 16 : 0 fatty acid and is associated with damage and death of the mutants at low temperature. Transformation of fab1 plants with a c......DNA from Brassica napus encoding a KAS II enzyme resulted in complementation of both mutant phenotypes. The dual complementation by expression of the single gene proves that low-temperature damage is a consequence of altered membrane unsaturation. The fab1 mutation is a single nucleotide change...... chain to bend. For functional analysis the equivalent Leu207Phe mutation was introduced into the fabB gene encoding the E. coli KAS I enzyme. Compared to wild-type, the Leu207Phe protein showed a 10-fold decrease in binding affinity for the fatty acid substrate, exhibited a modified behavior during size...

  7. Photolysis of carotenoids in chloroform: enhanced yields of carotenoid radical cations in the presence of a tryptophan ester

    International Nuclear Information System (INIS)

    El-Agamey, Ali; Burke, Marc; Edge, Ruth; Land, Edward J.; McGarvey, David J.; Truscott, T. George

    2005-01-01

    The presence of an acetyl tryptophan ester gives rise to enhanced yields of carotenoid radical cations in chloroform following 355 nm laser excitation of the carotenoid, even though the tryptophan does not absorb at this wavelength. The increase is attributed to positive charge transfer from semi-oxidized tryptophan itself generated by light absorbed by the carotenoid. The mechanism of these radical processes has been elucidated by pulse radiolysis studies

  8. Tryptophan pathway alterations in the postpartum period and in acute postpartum psychosis and depression.

    Science.gov (United States)

    Veen, Cato; Myint, Aye Mu; Burgerhout, Karin M; Schwarz, Markus J; Schütze, Gregor; Kushner, Steven A; Hoogendijk, Witte J; Drexhage, Hemmo A; Bergink, Veerle

    2016-01-01

    Women are at very high risk for the first onset of acute and severe mood disorders the first weeks after delivery. Tryptophan breakdown is increased as a physiological phenomenon of the postpartum period and might lead to vulnerability for affective psychosis (PP) and severe depression (PD). The aim of the current study was to investigate alterations in tryptophan breakdown in the physiological postpartum period compared to patients with severe postpartum mood disorders. We included 52 patients (29 with PP, 23 with PD), 52 matched healthy postpartum women and 29 healthy non-postpartum women. Analyzes of serum tryptophan metabolites were performed using LC-MS/MS system for tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid and 5-hydroxyindoleacetic acid. The first two months of the physiological postpartum period were characterized by low tryptophan levels, increased breakdown towards kynurenine and a downstream shift toward the 3-OH-kynurenine arm, away from the kynurenic acid arm. Kynurenine was significantly lower in patients with PP and PD as compared to healthy postpartum women (p=0.011 and p=0.001); the remaining tryptophan metabolites demonstrated few differences between patients and healthy postpartum women. Low prevalence of the investigated disorders and strict exclusion criteria to obtain homogenous groups, resulted in relatively small sample sizes. The high kynurenine levels and increased tryptophan breakdown as a phenomenon of the physiological postpartum period was not present in patients with severe postpartum mood disorders. No differences were observed in the levels of the 'neurotoxic' 3-OH-kynurenine and the 'neuroprotective' kynurenic acid arms between patients and healthy postpartum women. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. From tryptophan to hydroxytryptophan: reflections on a busy life.

    Science.gov (United States)

    Fisher, Hans

    2009-01-01

    Given the very difficult odyssey of my early years, who could have imagined the incredible and successful journey that constituted my life path after age 13? I was born into a Jewish family in Breslau, Germany, right before the rise of Nazism and Hitler's election. After Kristallnacht, when my father was taken to Buchenwald Concentration Camp, we had to leave Germany as soon as possible. The first opportunity came in May of 1939, when we boarded the SS St. Louis bound for Havana, Cuba. Almost all passengers were denied entrance into Cuba, and the ship had to go back to Europe, where I ended up in France. In December of 1939, during World War II, I was fortunate to be able to leave France. This time I made it to Cuba, where my father was already in residence. A year later, my entire family was allowed into the United States. I took advantage of all the educational resources in this land of opportunity. I graduated valedictorian of my high school class and earned a four-year scholarship to Rutgers University, where I obtained a Bachelor of Science degree. I went on to earn a Master's degree from the University of Connecticut and finally a PhD from the University of Illinois. Within two months after graduating from Illinois, I was hired as an assistant professor of nutritional biochemistry at Rutgers, where I enjoyed a most productive research and teaching career. My PhD research involved tryptophan and niacin metabolism in the chick, and upon arrival at Rutgers I continued amino acid studies with the goal of assessing the essential amino acid requirements for egg production. This research was crowned with success and was followed with amino acid requirement studies for maintenance and for growth in rabbits, and ultimately with a reevaluation of requirements in adult humans. An outgrowth of the maintenance requirements led to a series of investigations into the metabolism of histidine, histamine, and carnosine (a histidine-containing dipeptide). Histamine, we found

  10. Plasma Tryptophan and the Kynurenine–Tryptophan Ratio Are Associated with the Acquisition of Statural Growth Deficits and Oral Vaccine Underperformance in Populations with Environmental Enteropathy

    Science.gov (United States)

    Kosek, Margaret N.; Mduma, Estomih; Kosek, Peter S.; Lee, Gwenyth O.; Svensen, Erling; Pan, William K. Y.; Olortegui, Maribel Paredes; Bream, Jay H.; Patil, Crystal; Asayag, Cesar Ramal; Sanchez, Graciela Meza; Caulfield, Laura E.; Gratz, Jean; Yori, Pablo Peñataro

    2016-01-01

    Early childhood enteric infections have adverse impacts on child growth and can inhibit normal mucosal responses to oral vaccines, two critical components of environmental enteropathy. To evaluate the role of indoleamine 2,3-dioxygenase 1 (IDO1) activity and its relationship with these outcomes, we measured tryptophan and the kynurenine–tryptophan ratio (KTR) in two longitudinal birth cohorts with a high prevalence of stunting. Children in rural Peru and Tanzania (N = 494) contributed 1,251 plasma samples at 3, 7, 15, and 24 months of age and monthly anthropometrics from 0 to 36 months of age. Tryptophan concentrations were directly associated with linear growth from 1 to 8 months after biomarker assessment. A 1-SD increase in tryptophan concentration was associated with a gain in length-for-age Z-score (LAZ) of 0.17 over the next 6 months in Peru (95% confidence interval [CI] = 0.11–0.23, P < 0.001) and a gain in LAZ of 0.13 Z-scores in Tanzania (95% CI = 0.03–0.22, P = 0.009). Vaccine responsiveness data were available for Peru only. An increase in kynurenine by 1 μM was associated with a 1.63 (95% CI = 1.13–2.34) increase in the odds of failure to poliovirus type 1, but there was no association with tetanus vaccine response. A KTR of 52 was 76% sensitive and 50% specific in predicting failure of response to serotype 1 of the oral polio vaccine. KTR was associated with systemic markers of inflammation, but also interleukin-10, supporting the association between IDO1 activity and immunotolerance. These results strongly suggest that the activity of IDO1 is implicated in the pathophysiology of environmental enteropathy, and demonstrates the utility of tryptophan and kynurenine as biomarkers for this syndrome, particularly in identifying those at risk for hyporesponsivity to oral vaccines. PMID:27503512

  11. Entry of a Six-Residue Antimicrobial Peptide Derived from Lactoferricin B into Single Vesicles and Escherichia coli Cells without Damaging their Membranes.

    Science.gov (United States)

    Moniruzzaman, Md; Islam, Md Zahidul; Sharmin, Sabrina; Dohra, Hideo; Yamazaki, Masahito

    2017-08-22

    Lactoferricin B (LfcinB) and shorter versions of this peptide have antimicrobial activity. However, the elementary processes of interactions of these peptides with lipid membranes and bacteria are still not well understood. To elucidate the mechanism of their antimicrobial activity, we investigated the interactions of LfcinB (4-9) (its sequence of RRWQWR) with Escherichia coli cells and giant unilamellar vesicles (GUVs). LfcinB (4-9) and lissamine rhodamine B red-labeled LfcinB (4-9) (Rh-LfcinB (4-9)) did not induce an influx of a membrane-impermeant fluorescent probe, SYTOX green, from the outside of E. coli cells into their cytoplasm, indicating that no damage occurred in their plasma membrane. To examine the activity of LfcinB (4-9) to enter E. coli cytoplasm, we investigated the interaction of Rh-LfcinB (4-9) with single cells of E. coli containing calcein using confocal microscopy. We found that Rh-LfcinB (4-9) entered the cytoplasm without leakage of calcein. Next, we investigated the interactions of Rh-LfcinB (4-9) with single GUVs of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC) mixtures containing a fluorescent probe, Alexa Fluor 647 hydrazide (AF647), using the single GUV method. The results indicate that Rh-LfcinB (4-9) outside the GUV translocated through the GUV membrane and entered its lumen without leakage of AF647. Interaction of Rh-LfcinB (4-9) with DNA increased its fluorescence intensity greatly. Therefore, we can conclude that Rh-LfcinB (4-9) can translocate across lipid membrane regions of the plasma membrane of E. coli cells to enter their cytoplasm without leakage of calcein and its antimicrobial activity is not due to damage of their plasma membranes.

  12. Plasma L-tryptophan concentration in major depressive disorder: new data and meta-analysis.

    Science.gov (United States)

    Ogawa, Shintaro; Fujii, Takashi; Koga, Norie; Hori, Hiroaki; Teraishi, Toshiya; Hattori, Kotaro; Noda, Takamasa; Higuchi, Teruhiko; Motohashi, Nobutaka; Kunugi, Hiroshi

    2014-09-01

    Tryptophan, an essential amino acid, is the precursor to serotonin and is metabolized mainly by the kynurenine pathway. Both serotonin and kynurenine have been implicated in the pathophysiology of major depressive disorder (MDD). However, plasma tryptophan concentration in patients with MDD has not unequivocally been reported to be decreased, which prompted us to perform a meta-analysis on previous studies and our own data. We searched the PubMed database for case-control studies published until August 31, 2013, using the search terms plasma AND tryptophan AND synonyms for MDD. An additional search was performed for the term amino acid instead of tryptophan. We obtained our own data in 66 patients with MDD (DSM-IV) and 82 controls who were recruited from March 2011 to July 2012. The majority of the patients were medicated (N = 53). Total plasma tryptophan concentrations were measured by the liquid chromatography/mass spectrometry method. We scrutinized 160 studies for eligibility. Original articles that were written in English and documented plasma tryptophan values in patients and controls were selected. We included 24 studies from the literature and our own data in the meta-analysis, which involved a total of 744 patients and 793 controls. Data on unmedicated patients (N = 156) and their comparison subjects (N = 203) were also extracted. To see the possible correlation between tryptophan concentrations and depression severity, meta-regression analysis was performed for 10 studies with the Hamilton Depression Rating Scale 17-item version score. In our case-control study, mean (SD) plasma tryptophan level was significantly decreased in the MDD patients versus the controls (53.9 [10.9] vs 57.2 [11.3] μmol/L; P = .03). The meta-analysis after adjusting for publication bias showed a significant decrease in patients with MDD with a modest effect size (Hedges g, -0.45). However, analysis on unmedicated subjects yielded a large effect (Hedges g, -0.84; P = .00015). We

  13. Lignans from Carthamus tinctorius suppress tryptophan breakdown via indoleamine 2,3-dioxygenase

    Science.gov (United States)

    Kuehnl, Susanne; Schroecksnadel, Sebastian; Temml, Veronika; Gostner, Johanna M.; Schennach, Harald; Schuster, Daniela; Schwaiger, Stefan; Rollinger, Judith M.; Fuchs, Dietmar; Stuppner, Hermann

    2013-01-01

    Seed extracts of Carthamus tinctorius L. (Asteraceae), safflower, have been traditionally used to treat coronary disease, thrombotic disorders, and menstrual problems but also against cancer and depression. A possible effect of C. tinctorius compounds on tryptophan-degrading activity of enzyme indoleamine 2,3-dioxygenase (IDO) could explain many of its activities. To test for an effect of C. tinctorius extracts and isolated compounds on cytokine-induced IDO activity in immunocompetent cells in vitro methanol and ethylacetate seed extracts were prepared from cold pressed seed cakes of C. tinctorius and three lignan derivatives, trachelogenin, arctigenin and matairesinol were isolated. The influence on tryptophan breakdown was investigated in peripheral blood mononuclear cells (PBMCs). Effects were compared to neopterin production in the same cellular assay. Both seed extracts suppressed tryptophan breakdown in stimulated PBMC. The three structurally closely related isolates exerted differing suppressive activity on PBMC: arctigenin (IC50 26.5 μM) and trachelogenin (IC50 of 57.4 μM) showed higher activity than matairesinol (IC50 >200 μM) to inhibit tryptophan breakdown. Effects on neopterin production were similar albeit generally less strong. Data show an immunosuppressive property of compounds which slows down IDO activity. The in vitro results support the view that some of the anti-inflammatory, anti-cancer and antidepressant properties of C. tinctorius lignans might relate to their suppressive influence on tryptophan breakdown. PMID:23867649

  14. Severe Tryptophan Starvation Blocks Onset of Conventional Persistence and Reduces Reactivation of Chlamydia trachomatis▿

    Science.gov (United States)

    Leonhardt, Ralf M.; Lee, Seung-Joon; Kavathas, Paula B.; Cresswell, Peter

    2007-01-01

    The intracellular survival of the bacterial pathogen Chlamydia trachomatis depends on protein synthesis by the microbe soon after internalization. Pharmacologic inhibition of bacterial translation inhibits early trafficking of the parasitophorous vacuole (inclusion) to the microtubule-organizing center (MTOC) and promotes its fusion with lysosomes, which is normally blocked by Chlamydia. Depletion of cellular tryptophan pools by gamma interferon-inducible indoleamine-2,3-dioxygenase (IDO) is believed to be the major innate immune mechanism controlling C. trachomatis infection in human cells, an action to which the bacteria can respond by converting into a nonreplicating but highly reactivatable persistent state. However, whether severe IDO-mediated tryptophan starvation can be sufficient to fully arrest the chlamydial life cycle and thereby counteract the onset of persistence is unknown. Here we demonstrate that at low exogenous tryptophan concentrations a substantial fraction of C. trachomatis bacteria fail to traffic to the MTOC or to switch into the conventional persistent state in gamma interferon-induced human cells. The organisms stay scattered in the cell periphery, do not retain infectivity, and display only low transcriptional activity. Importantly, the rate at which these aberrant Chlamydia bacteria become reactivated upon replenishment of cellular tryptophan pools is substantially lower. Thus, severe tryptophan depletion in cells with high IDO activity affects chlamydial development more rigorously than previously described. PMID:17724071

  15. The effect of acute tryptophan depletion on mood and impulsivity in polydrug ecstasy users.

    Science.gov (United States)

    Young, Simon N; Regoli, Martine; Leyton, Marco; Pihl, Robert O; Benkelfat, Chawki

    2014-02-01

    Several studies suggest users of 3,4-methylenedioxymethamphetamine (ecstasy) have low levels of serotonin. Low serotonin may make them susceptible to lowered mood. This work aims to study the acute effects on mood and impulsivity of lowering serotonin levels with acute tryptophan depletion in polydrug ecstasy users and to determine whether effects were different in men and women. In a double-blind cross-over study, participants who had used ecstasy at least 25 times (n = 13) and nonuser controls (n = 17) received a tryptophan-deficient amino acid mixture and a control amino acid mixture containing tryptophan, at least 1 week apart. Mood was measured using the profile of mood states, and impulsivity was measured with the Go/No-Go task. The main result shows that a lowering of mood after acute tryptophan depletion occurred only in female polydrug ecstasy users (n = 7), relative to controls (n = 9). Results from the Go/No-Go task suggested that impulsivity was not increased by acute tryptophan depletion in polydrug ecstasy users. The group sizes were small, when males and females were considered separately. Women polydrug ecstasy users appear to be more susceptible than men to the effects of lowered serotonin levels. If use of ecstasy alone or in conjunction with other drugs causes progressive damage of serotonin neurons, women polydrug ecstasy users may become susceptible to clinical depression.

  16. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  17. Residue specific hydration of primary cell wall potato pectin identified by solid-state 13C single-pulse MAS and CP/MAS NMR spectroscopy

    DEFF Research Database (Denmark)

    Larsen, Flemming Hofmann; Chrestensen, Inge Byg; Damager, Iben

    2011-01-01

    Hydration of rhamnogalacturonan-I (RG-I) derived from potato cell wall was analyzed by 13C single-pulse (SP) magic-angle-spinning (MAS) and 13C cross-polarization (CP) MAS nuclear magnetic resonance (NMR) and supported by 2H SP/MAS NMR experiments. The study shows that the arabinan side chains...... hydrate more readily than the galactan side chains and suggests that the overall hydration properties can be controlled by modifying the ratio of these side chains. Enzymatic modification of native (NA) RG-I provided samples with reduced content of arabinan (sample DA), galactan (sample DG), or both side...... chains (sample DB). Results of these samples suggested that hydration properties were determined by the length and character of the side chains. NA and DA exhibited similar hydration characteristics, whereas DG and DB were difficult to hydrate because of the less hydrophilic properties of the rhamnose...

  18. Mechanistic Insights into Radical-Mediated Oxidation of Tryptophan from ab Initio Quantum Chemistry Calculations and QM/MM Molecular Dynamics Simulations.

    Science.gov (United States)

    Wood, Geoffrey P F; Sreedhara, Alavattam; Moore, Jamie M; Wang, John; Trout, Bernhardt L

    2016-05-12

    An assessment of the mechanisms of (•)OH and (•)OOH radical-mediated oxidation of tryptophan was performed using density functional theory calculations and ab initio plane-wave Quantum Mechanics/Molecular Mechanics (QM/MM) molecular dynamics simulations. For the (•)OH reactions, addition to the pyrrole ring at position 2 is the most favored site with a barrierless reaction in the gas phase. The subsequent degradation of this adduct through a H atom transfer to water was intermittently observed in aqueous-phase molecular dynamics simulations. For the (•)OOH reactions, addition to the pyrrole ring at position 2 is the most favored pathway, in contrast to the situation in the model system ethylene, where concerted addition to the double bond is preferred. From the (•)OOH position 2 adduct QM/MM simulations show that formation of oxy-3-indolanaline occurs readily in an aqueous environment. The observed transformation starts from an initial rupture of the O-O bond followed by a H atom transfer with the accompanying loss of an (•)OH radical to solution. Finally, classical molecular dynamics simulations were performed to equate observed differential oxidation rates of various tryptophan residues in monoclonal antibody fragments. It was found that simple parameters derived from simulation correlate well with the experimental data.

  19. Effects of environmental lighting and tryptophan devoid diet on the rat vaginal cycle.

    Science.gov (United States)

    Giammanco, S; Ernandes, M; La Guardia, M

    1997-09-01

    Cerebral serotonin level influences luteinizing hormone release and, consequently, ovulation. The present study evaluated the effects of precooked maize meal (polenta), a diet almost devoid of tryptophan the serotonin precursor on the alterations of the estrus cycle as measured by vaginal smears analysis in Wistar rats. Several conditions of environmental lighting were used in order to modify ovarian cycle: 1) natural alternating light/dark cycle; 2) continuous darkness; 3) continuous light by sodium steams: 4) continuous light by fluorescent neon tubes. Rats bred in continuous lighting showed estrus-proestrus rate significantly greater than rats bred in normal lighting or in continuous darkness. The feeding with precooked maize meal suppressed persistent estrus in rats bred in continuous lighting, and significantly cut down the estrus-proestrus frequency in any condition of environmental lighting. Our results lead to hypothesize that polenta diet, for its low tryptophan content, cutting down both tryptophan plasma content and serotonin neuronal synthesis, promotes luteinizing hormone peak.

  20. Dosimetry of D- and L-enantiomers of 11C-labeled tryptophan and valine

    International Nuclear Information System (INIS)

    Washburn, L.C.; Byrd, B.L.; Sun, T.T.; Crook, J.E.; Hubner, K.F.; Coffey, J.L.; Watson, E.E.

    1985-01-01

    We have previously reported the radiation dosimetry of 11 C-labeled DL-tryptophan and DL-valine, as well as clinical pancreatic imaging studies with these agents. Because of significant uptake in both normal pancreas and in pancreatic tumors (thought to be due to the presence of the D-enantiomer), differential diagnosis of pancreatic carcinoma was not feasible. High-performance liquid chromatographic (HPLC) methods were developed for rapid resolution of 11 C-labeled DL-tryptophan and DL-valine. Radiation dose estimates to the various organs in man were calculated for the D- and L-enantiomers of 11 C-labeled tryptophan and valine, based on tissue distribution data in rats. The dose estimates were sufficiently low that 20-mCi doses of each of the enantiomeric amino acids were approved by the FDA for intravenous administration to humans. 21 refs., 3 tabs

  1. Dosimetry of D- and L-enantiomers of 11C-labeled tryptophan and valine

    International Nuclear Information System (INIS)

    Washburn, L.C.; Byrd, B.L.; Sun, T.T.; Crook, J.E.; Hubner, K.F.; Coffey, J.L.; Watson, E.E.

    1986-01-01

    The authors have previously reported the radiation dosimetry of 11 C-labeled DL-tryptophan and DL-valine, as well as clinical pancreatic imaging studies with these agents. Because of significant uptake in both normal pancreas and in pancreatic tumors (thought to be due to the presence of the D-enantiomer), differential diagnosis of pancreatic carcinoma was not feasible. High-performance liquid chromatographic (HPLC) methods were developed for rapid resolution of 11 C-labeled DL-tryptophan and DL-valine. Radiation dose estimates to the various organs in man were calculated for the D- and L-enantiomers of 11 C-labeled tryptophan and valine, based on tissue distribution data in rats. The dose estimates were sufficiently low that 20-mCi doses of each of the enantiomeric amino acids were approved by the FDA for intravenous administration to humans. 21 references, 3 tables

  2. Synthesis of no-carrier-added alpha-[11C]methyl-L-tryptophan

    International Nuclear Information System (INIS)

    Chaly, T.; Diksic, M.

    1988-01-01

    Described here is a synthesis of no-carrier-added alpha-[ 11 C]methyl-L-tryptophan based on alkylation with 11 CH 3 I of an anion generated by reacting the Schiff base of L-tryptophan methyl ester with di-isopropylamine. The synthesis requires approximately 30 min after the end of 11 CO 2 collection and gives alpha-[ 11 C]methyl-L-tryptophan in a 20-25% radiochemical yield calculated at the end of the synthesis and without correction for radioactive decay. The specific activity of the final radiopharmaceutical, measured at the end of the synthesis, was around 2000 Ci/mmol. Data confirming the stereospecificity of the synthesis are also presented

  3. GPR142 Controls Tryptophan-Induced Insulin and Incretin Hormone Secretion to Improve Glucose Metabolism.

    Directory of Open Access Journals (Sweden)

    Hua V Lin

    Full Text Available GPR142, a putative amino acid receptor, is expressed in pancreatic islets and the gastrointestinal tract, but the ligand affinity and physiological role of this receptor remain obscure. In this study, we show that in addition to L-Tryptophan, GPR142 signaling is also activated by L-Phenylalanine but not by other naturally occurring amino acids. Furthermore, we show that Tryptophan and a synthetic GPR142 agonist increase insulin and incretin hormones and improve glucose disposal in mice in a GPR142-dependent manner. In contrast, Phenylalanine improves in vivo glucose disposal independently of GPR142. Noteworthy, refeeding-induced elevations in insulin and glucose-dependent insulinotropic polypeptide are blunted in Gpr142 null mice. In conclusion, these findings demonstrate GPR142 is a Tryptophan receptor critically required for insulin and incretin hormone regulation and suggest GPR142 agonists may be effective therapies that leverage amino acid sensing pathways for the treatment of type 2 diabetes.

  4. Tryptophan metabolism in tsetse flies and the consequences of its derangement

    Directory of Open Access Journals (Sweden)

    R. H. Gooding

    1987-01-01

    Full Text Available Literature comparing salmon and wild type Glossina morsitans morsitans and that comparing tan and wild type Glossina palpalis palpalis is reviewed. New information is presented on behaviour and biochemistry of salmon and wild type G. m. morsitans. The eye color mutants result from two lesions in the tryptophan to xanthommatin pathway: lack of tryptophan oxygenase in G. m morsitans and failure to produce or retain xanthommatin in eyes (but not in testes of G. p. palpalis. The salmon allele in G. m. morsitans is pleiotropic and profoundly affects many aspects of fly biology including longevity, reproductive capacity, vision, vectorial capacity and duration of flight, but not circadian rhythms. The tan allele in G. p. palpalis has little effect upon the biology of flies under laboratory conditions, except that tan flies appear less active than normal. Adult tsetse flies metabolize tryptophan to kynurenine which is excreted; fluctuations in activities of the enzymes producing kynurenine suggest this pathway is under metabolic control.

  5. Identification of Functional Single-Nucleotide Polymorphisms Affecting Leaf Hair Number in Brassica rapa.

    Science.gov (United States)

    Zhang, Wenting; Mirlohi, Shirin; Li, Xiaorong; He, Yuke

    2018-06-01

    Leaf traits affect plant agronomic performance; for example, leaf hair number provides a morphological indicator of drought and insect resistance. Brassica rapa crops have diverse phenotypes, and many B. rapa single-nucleotide polymorphisms (SNPs) have been identified and used as molecular markers for plant breeding. However, which SNPs are functional for leaf hair traits and, therefore, effective for breeding purposes remains unknown. Here, we identify a set of SNPs in the B. rapa ssp. pekinenesis candidate gene BrpHAIRY LEAVES1 ( BrpHL1 ) and a number of SNPs of BrpHL1 in a natural population of 210 B. rapa accessions that have hairy, margin-only hairy, and hairless leaves. BrpHL1 genes and their orthologs and paralogs have many SNPs. By intensive mutagenesis and genetic transformation, we selected the functional SNPs for leaf hairs by the exclusion of nonfunctional SNPs and the orthologous and paralogous genes. The residue tryptophan-92 of BrpHL1a was essential for direct interaction with GLABROUS3 and, thus, necessary for the formation of leaf hairs. The accessions with the functional SNP leading to substitution of the tryptophan-92 residue had hairless leaves. The orthologous BrcHL1b from B. rapa ssp. chinensis regulates hair formation on leaf margins rather than leaf surfaces. The selected SNP for the hairy phenotype could be adopted as a molecular marker for insect resistance in Brassica spp. crops. Moreover, the procedures optimized here can be used to explain the molecular mechanisms of natural variation and to facilitate the molecular breeding of many crops. © 2018 American Society of Plant Biologists. All rights reserved.

  6. Single residue AAV capsid mutation improves transduction of photoreceptors in the Abca4-/- mouse and bipolar cells in the rd1 mouse and human retina ex vivo.

    Science.gov (United States)

    De Silva, Samantha R; Charbel Issa, Peter; Singh, Mandeep S; Lipinski, Daniel M; Barnea-Cramer, Alona O; Walker, Nathan J; Barnard, Alun R; Hankins, Mark W; MacLaren, Robert E

    2016-11-01

    Gene therapy using adeno-associated viral (AAV) vectors for the treatment of retinal degenerations has shown safety and efficacy in clinical trials. However, very high levels of vector expression may be necessary for the treatment of conditions such as Stargardt disease where a dual vector approach is potentially needed, or in optogenetic strategies for end-stage degeneration in order to achieve maximal light sensitivity. In this study, we assessed two vectors with single capsid mutations, rAAV2/2(Y444F) and rAAV2/8(Y733F) in their ability to transduce retina in the Abca4 -/- and rd1 mouse models of retinal degeneration. We noted significantly increased photoreceptor transduction using rAAV2/8(Y733F) in the Abca4 -/- mouse, in contrast to previous work where vectors tested in this model have shown low levels of photoreceptor transduction. Bipolar cell transduction was achieved following subretinal delivery of both vectors in the rd1 mouse, and via intravitreal delivery of rAAV2/2(Y444F). The successful use of rAAV2/8(Y733F) to target bipolar cells was further validated on human tissue using an ex vivo culture system of retinal explants. Capsid mutant AAV vectors transduce human retinal cells and may be particularly suited to treat retinal degenerations in which high levels of transgene expression are required.

  7. Pigment Production on L-Tryptophan Medium by Cryptococcus gattii and Cryptococcus neoformans

    Science.gov (United States)

    Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

    2014-01-01

    In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin. PMID:24736553

  8. Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

    Science.gov (United States)

    Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

    2014-01-01

    In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

  9. Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    Stuart Chaskes

    Full Text Available In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

  10. Involvement of tryptophan hydroxylase 2 gene polymorphisms in susceptibility to tic disorder in Chinese Han population.

    Science.gov (United States)

    Zheng, Ping; Li, Erzhen; Wang, Jianhua; Cui, Xiaodai; Wang, Liwen

    2013-01-29

    Tryptophan hydroxylase-2 (TPH2) is a potential candidate gene for screening tic disorder (TD). A case-control study was performed to examine the association between the TPH2 gene and TD. The Sequenom® Mass ARRAY iPLEX GOLD System was used to genotype two single nucleotide polymorphisms (SNPs) of the TPH2 gene in 149 TD children and in 125 normal controls. For rs4565946, individuals with the TT genotype showed a significantly higher risk of TD than those with TC plus CC genotypes [odds ratio (OR) =3.077, 95% confidence interval (CI): 1.273-7.437; P = 0.009], as did male TD children with the TT genotype (OR = 3.228, 95% CI: 1.153-9.040; P = 0.020). The G allele of rs4570625 was significantly more frequent in TD children with higher levels of tic symptoms (Yale Global Tic Severity Scale, YGTSS) than those in controls among the male children (OR = 1.684, 95%: 1.097-2.583; P = 0.017]. TD children with severe tic symptoms had significantly higher frequencies of rs4546946 TT genotype than did normal controls in boys (OR = 3.292, 95% CI: 1.139-9.513; P = 0.022). We also found that genotype distributions of both SNPs were different between the Asian and European populations. Our results indicated that the TT genotype of rs4565946 is a potential genetic risk factor for TD, and the allele G of rs4570625 might be associated with the severity of tic symptoms in boys. These polymorphisms might be susceptibility loci for TD in the Chinese Han population. Because of the confounding of co-existing attention deficit hyperactivity disorder (ADHD),these findings need to be confirmed by studies in much larger samples.

  11. The pharmacokinetics of L-tryptophan following its intravenous and oral administration.

    OpenAIRE

    Green, A R; Aronson, J K; Cowen, P J

    1985-01-01

    The pharmacokinetics of L-tryptophan (5 g and 7.5 g) have been studied after its intravenous administration to healthy subjects and the results compared with those obtained after oral administration (0.7 g-3.5 g). In order to do this, we have re-analysed previously published data relating to oral administration. The data obtained following the oral administration of L-tryptophan suggest that the total body clearance and apparent volume of distribution are saturable. The pharmacokinetics of tr...

  12. Don't panic. A guide to tryptophan depletion with disorder-specific anxiety provocation.

    Science.gov (United States)

    Hood, S D; Bell, C J; Argyropoulos, S V; Nutt, D J

    2016-11-01

    The 2002 paper "Does 5-HT restrain panic? A tryptophan depletion study in panic disorder patients recovered on paroxetine" by Bell and colleagues - reprinted in this issue of the Journal - reports on a study undertaken in the halcyon days of David Nutt's Psychopharmacology Unit at the University of Bristol, England. In this invited commentary authors of the original work discuss the impact of this paper on the field of acute tryptophan depletion research (especially in the field of clinical anxiety disorders) and the development of disorder-specific anxiogenic provocations over the past decade. © The Author(s) 2016.

  13. L-tryptophan synthesis from 14C-anthranilic acid in plants with high and low tryptophan content

    International Nuclear Information System (INIS)

    Kutacek, M.; Eder, J.; Vackova, K.; Prochazka, S.

    1978-01-01

    The biosynthesis of L-tryptophan (L-trp) from anthranilic acid- 14 C (AA- 14 C) in undamaged organs of the seedlings of kohlrabi and peas, with high L-trp content and maize plants, with low L-trp content was compared. As for maize the experiments were carried out with normal and opaque-2 phenotypes, both with the seedlings and with the ripening kernels. AA- 14 C is metabolized in the plants to L-trp pool and to glycosyl esters of AA. In maize seedlings L-trp- 14 C is synthesized relatively less than in kohlrabi and in pea. The de novo formation of L-trp- 14 C is stopped earlier in maize than in kohlrabi. The level of free L-trp- 14 C is relatively low in maize in comparison with kohlrabi and peas. In spite of this the formation of L-trp- 14 C from AA- 14 C is sufficient in maize to incorporate L-trp both into the proteins and into a secondary metabolite that is not yet defined. At the period of seedlings the incorporation in maize of L-trp into the proteins is comparable with that in kohlrabi, and it is maximum in pea. Maize, at the stage of germination, thus forms proteins rich in L-trp. The formation of free L-trp is approximately ten times lower in ripening kernels and in the leaves adjacent to the ear and it further decreases in the course of the ripening of the kernels. Although the activity of the biosynthesis of the AA- 14 C→L-trp- 14 C pathway is relatively lower in maize than in kohlrabi and peas, this pathway is most responsible for the differences in the content of L-trp in these plants. Neither amitrol nor histidine affected the biosynthesis of L-trp in kohlrabi; the interaction of the biosynthetic pathways of L-trp and histidine known in microorganisms is thus not important in a higher plant. (author)

  14. Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

    Science.gov (United States)

    Iwata, Ayumi; Matsuki, Atsushi

    2018-02-01

    pure or fresh calcite, Ca(NO3)2, and (NH4)2SO4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

  15. Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

    Directory of Open Access Journals (Sweden)

    A. Iwata

    2018-02-01

    dust particles. Also, relatively pure or fresh calcite, Ca(NO32, and (NH42SO4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

  16. Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: failure to affect performance

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Raaymakers, J S; Saris, W H

    1995-01-01

    1. An increased uptake of tryptophan in the brain may increase serotoninergic activity and recently has been suggested to be a cause of fatigue during prolonged exercise. The present study, therefore, investigates whether ingestion of tryptophan or the competing branched-chain amino acids (BCAAs......) affect performance. Ten endurance-trained male athletes were studied during cycle exercise at 70-75% maximal power output, while ingesting, ad random and double-blind, drinks that contained 6% sucrose (control) or 6% sucrose supplemented with (1) tryptophan (3 g l-1), (2) a low dose of BCAA (6 g l-1...... tryptophan ingestion caused a 7- to 20-fold increase. Exercise time to exhaustion was not different between treatments (122 +/- 3 min). 3. The data suggest that manipulation of tryptophan supply to the brain either has no additional effect upon serotoninergic activity during prolonged exhaustive exercise...

  17. Tryptophan tags and de novo designed complementary affinity ligands for the expression and purification of recombinant proteins.

    Science.gov (United States)

    Pina, Ana Sofia; Carvalho, Sara; Dias, Ana Margarida G C; Guilherme, Márcia; Pereira, Alice S; Caraça, Luciana T; Coroadinha, Ana Sofia; Lowe, Christopher R; Roque, A Cecília A

    2016-11-11

    A common strategy for the production and purification of recombinant proteins is to fuse a tag to the protein terminal residues and employ a "tag-specific" ligand for fusion protein capture and purification. In this work, we explored the effect of two tryptophan-based tags, NWNWNW and WFWFWF, on the expression and purification of Green Fluorescence Protein (GFP) used as a model fusion protein. The titers obtained with the expression of these fusion proteins in soluble form were 0.11mgml -1 and 0.48mgml -1 for WFWFWF and NWNWNW, respectively. A combinatorial library comprising 64 ligands based on the Ugi reaction was prepared and screened for binding GFP-tagged and non-tagged proteins. Complementary ligands A2C2 and A3C1 were selected for the effective capture of NWNWNW and WFWFWF tagged proteins, respectively, in soluble forms. These affinity pairs displayed 10 6 M -1 affinity constants and Qmax values of 19.11±2.60ugg -1 and 79.39ugg -1 for the systems WFWFWF AND NWNWNW, respectively. GFP fused to the WFWFWF affinity tag was also produced as inclusion bodies, and a refolding-on column strategy was explored using the ligand A4C8, selected from the combinatorial library of ligands but in presence of denaturant agents. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Simultaneous determination of tryptophan and 8 metabolites in human plasma by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Boulet, Lysiane; Faure, Patrice; Flore, Patrice; Montérémal, Julien; Ducros, Véronique

    2017-06-01

    Tryptophan (Trp) is an essential amino-acid and the precursor of many biologically active substances such as kynurenine (KYN) and serotonin (5HT). Its metabolism is involved in different physiopathological states, such as cardiovascular diseases, cancer, immunomodulation or depression. Hence, the quantification of Trp catabolites, from both KYN and 5HT pathways, might be usefulfor the discovery of novel diagnostic and follow-up biomarkers. We have developed a simple method for quantification of Trp and 8 of its metabolites,involved in both KYN and 5HT pathways, using liquid chromatography coupled to tandem mass spectrometry. We also validated the methodin human plasma samples, according to NF EN ISO 15189 criteria. Our method shows acceptable intra- and inter-day coefficients of variation (CV) (<12% and <16% respectively). The linearity entirelycovers the human plasma range. Stabilities of whole blood and of residues weredetermined, as well as the use of 2 different types of collectiontube, enabling us to adapt our process. Matrix effects and reference values showed good agreement compared to the literature. We propose here a method allowing the simultaneous quantification of a panel of Trp catabolites, never used before to our knowledge. This method, witha quickchromatographic runtime (15min) and simple sample preparation, has beenvalidated according to NF EN ISO 15189 criteria. The method enables the detailed analysis of these metabolic pathways, which are thought to be involved in a number of pathological conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Mechanisms of hydrogen exchange in proteins from nuclear magnetic resonance studies of individual tryptophan indole NH hydrogens in lysozyme

    International Nuclear Information System (INIS)

    Wedin, R.E.; Delepierre, M.; Dobson, C.M.; Poulsen, F.M.

    1982-01-01

    The individual rates of solvent exchange of the six tryptophan indole NH hydrogens of lysozyme in 2 H 2 O have been measured over a wide range of temperatures by using 1 H NMR. Two distinct mechanisms for exchange have been identified, one characterized by a high activation energy and the other by a much lower activation energy. The high-energy process has been shown to be associated directly with the cooperative thermal unfolding of the protein and is the dominant mechanism for exchange of the most slowly exchanging hydrogen even 15 0 C below the denaturation temperature. Rate constants and activation energies for the folding and unfolding reactions were obtained from the experimental exchange rates. At low temperatures, a lower activation energy mechanism is dominant for all hydrogens, and this can be associated with local fluctuations in the protein structure which allow access of solvent. The relative exchange rates and activation energies can only qualitatively be related to the different environments of the residues in the crystal structure. There is provisional evidence that a mechanism intermediate between these two extremes may be significant for some hydrogens under restricted conditions

  20. Comprehensive analysis of the tryptophan metabolome in urine of patients with acute intermittent porphyria.

    Science.gov (United States)

    Gomez-Gomez, Alex; Marcos, Josep; Aguilera, Paula; To-Figueras, Jordi; Pozo, Oscar J

    2017-08-15

    Acute intermittent porphyria (AIP) is a rare metabolic disorder due to a deficiency of porphobilinogen deaminase, the third enzyme of the heme biosynthetic pathway. This low enzymatic activity may predispose to the appearance of acute neurological attacks. Seminal studies suggested that AIP was associated with changes in tryptophan homeostasis with inconclusive results. Therefore, the aim of this study was to analyze the urinary metabolome of AIP patients focusing on tryptophan metabolism using state-of-the-art technology. This was a case-control study including a group of 25 AIP patients with active biochemical disease and increased excretion of heme-precursors and 25 healthy controls. Tryptophan and related compounds and metabolites including: large neutral amino acids (LNAAs), serotonin, kynurenine, kynurenic acid and anthranilic acid were quantified in urine by liquid chromatography tandem-mass spectrometry (LC-MS/MS). Twenty-nine biological markers (including metabolic ratios and absolute concentrations) were compared between patients and controls. Significant differences were found in the tryptophan-kynurenine metabolic pathway. Compared to controls, AIP patients showed: (a) increased urinary excretion of kynurenine and anthranilic acid (Pmetabolome of hepatic porphyrias. Copyright © 2017. Published by Elsevier B.V.

  1. pH tuning of Nafion for selective detection of tryptophan

    International Nuclear Information System (INIS)

    Frith, K.-A.; Limson, J.L.

    2009-01-01

    Selective and sensitive detection of the amino acid tryptophan is of importance in food processing, pharmaceutical formulations and in biological fluids. Electrochemical methods of detection of tryptophan are hampered by sluggish electron transfer kinetics and in complex matrices through overlapping peaks from interferents. This study examines the potential of the cation exchange membrane Nafion to enhance selectivity and sensitivity of this analyte through a seldom explored feature of this membrane: pH manipulation. A detailed examination of the effect of pH on the selectivity afforded by Nafion as a function of the analyte charge is presented. Selective detection of tryptophan and significant increases in sensitivity of its detection was observed in the presence of melatonin, dopamine and other interferents present in a pharmaceutical formulation through manipulation of the pH of the solution. At pH 3.0 at a Nafion-modified electrode, changes in the protonation of melatonin and tryptophan lowered the anodic potential of the analytes in a non-uniform manner increasing the peak resolution and permitting analyses with detection limits of 1.6 ± 0.1 nM and 1.6 ± 0.2 nM, respectively.

  2. Physiological roles of tryptophan in teleosts: current knowledge and perspectives for future studies

    DEFF Research Database (Denmark)

    Hoseini, Seyyed Morteza; Pérez-Jiménez, Amelia; Costas, Benjamin

    2017-01-01

    from the neuroendocrine to the immune system in vertebrates. In aquaculture, extensive research has been performed to optimize the levels of tryptophan in the commercial diets for many fish species. Providing adequate levels of this amino acid is critically important for fish growth but also for fish...

  3. Tryptophan biosynthesis in stramenopiles: eukaryotic winners in the diatom complex chloroplast

    Czech Academy of Sciences Publication Activity Database

    Jiroutová, Kateřina; Horák, Aleš; Bowler, C.; Oborník, Miroslav

    2007-01-01

    Roč. 65, č. 5 (2007), s. 496-511 ISSN 0022-2844 R&D Projects: GA AV ČR IAA500220502 Institutional research plan: CEZ:AV0Z60220518 Keywords : tryptophan synthesis * mosaic origin * diatom * Oomycetes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2007

  4. PYROLYTIC PRODUCTS FROM TRYPTOPHAN AND GLUTAMIC-ACID ARE POSITIVE IN THE MAMMALIAN SPOT-TEST

    DEFF Research Database (Denmark)

    Jensen, Niels Juul

    1983-01-01

    Pyrolysates of tryptophan (Trp-P-2) and glutamic acid (Glu-P-1) are known mutagens in in vitro short term mutagenicity tests, and have also shown carcinogenic effects in long term animal studies. The present study demonstrates that they also produce mutations in somatic cells. This result...

  5. Lactococcus lactis as expression host for the biosynthetic incorporation of tryptophan analogues into recombinant proteins

    NARCIS (Netherlands)

    El Khattabi, Mohamed; van Roosmalen, Maarten L.; Jager, Dennis; Metselaar, Heidi; Permentier, Hjalmar; Leenhouts, Kees; Broos, Jaap

    2008-01-01

    Incorporation of Trp (tryptophan) analogues into a protein may facilitate its structural analysis by spectroscopic techniques. Development of a biological system for the biosynthetic incorporation of such analogues into proteins is of considerable importance. The Gram-negative Escherichia coli is

  6. Recognizing emotions in faces : effects of acute tryptophan depletion and bright light

    NARCIS (Netherlands)

    aan het Rot, Marije; Coupland, Nicholas; Boivin, Diane B.; Benkelfat, Chawki; Young, Simon N.

    2010-01-01

    In healthy never-depressed individuals, acute tryptophan depletion (ATD) may selectively decrease the accurate recognition of fearful facial expressions. Here we investigated the perception of facial emotions after ATD in more detail. We also investigated whether bright light, which can reverse

  7. Dietary l-tryptophan leaves a lasting impression on the brain and the stress response

    DEFF Research Database (Denmark)

    Höglund, Erik; Øverli, Øyvind; Åberg Andersson, Madelene

    2017-01-01

    Comparative models suggest that effects of dietary tryptophan (Trp) on brain serotonin (5-hydroxytryptamine; 5-HT) neurochemistry and stress responsiveness are present throughout the vertebrate lineage. Moreover, hypothalamic 5-HT seems to play a central role in control of the neuroendocrine stre...

  8. No Tryptophan, Tyrosine and Phenylalanine Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder

    NARCIS (Netherlands)

    Bergwerff, C.E.; Luman, M.; Blom, H.J.; Oosterlaan, J.

    2016-01-01

    Background The aim of the current study was to explore the role of aromatic amino acids (AAAs) in blood in relation to attention-deficit/hyperactivity disorder (ADHD). Given their impact on the synthesis of serotonin and dopamine, decreased concentrations of the AAAs tryptophan, tyrosine and

  9. Reprint of 'pH tuning of Nafion for selective detection of tryptophan'

    Energy Technology Data Exchange (ETDEWEB)

    Frith, K.-A. [Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6140 (South Africa); Limson, J.L., E-mail: j.limson@ru.ac.z [Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6140 (South Africa)

    2010-05-30

    Selective and sensitive detection of the amino acid tryptophan is of importance in food processing, pharmaceutical formulations and in biological fluids. Electrochemical methods of detection of tryptophan are hampered by sluggish electron transfer kinetics and in complex matrices through overlapping peaks from interferents. This study examines the potential of the cation exchange membrane Nafion to enhance selectivity and sensitivity of this analyte through a seldom explored feature of this membrane: pH manipulation. A detailed examination of the effect of pH on the selectivity afforded by Nafion as a function of the analyte charge is presented. Selective detection of tryptophan and significant increases in sensitivity of its detection was observed in the presence of melatonin, dopamine and other interferents present in a pharmaceutical formulation through manipulation of the pH of the solution. At pH 3.0 at a Nafion-modified electrode, changes in the protonation of melatonin and tryptophan lowered the anodic potential of the analytes in a non-uniform manner increasing the peak resolution and permitting analyses with detection limits of 1.6 +- 0.1 nM and 1.6 +- 0.2 nM, respectively.

  10. pH tuning of Nafion for selective detection of tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Frith, K.-A. [Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6140 (South Africa); Limson, J.L. [Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6140 (South Africa)], E-mail: j.limson@ru.ac.za

    2009-05-01

    Selective and sensitive detection of the amino acid tryptophan is of importance in food processing, pharmaceutical formulations and in biological fluids. Electrochemical methods of detection of tryptophan are hampered by sluggish electron transfer kinetics and in complex matrices through overlapping peaks from interferents. This study examines the potential of the cation exchange membrane Nafion to enhance selectivity and sensitivity of this analyte through a seldom explored feature of this membrane: pH manipulation. A detailed examination of the effect of pH on the selectivity afforded by Nafion as a function of the analyte charge is presented. Selective detection of tryptophan and significant increases in sensitivity of its detection was observed in the presence of melatonin, dopamine and other interferents present in a pharmaceutical formulation through manipulation of the pH of the solution. At pH 3.0 at a Nafion-modified electrode, changes in the protonation of melatonin and tryptophan lowered the anodic potential of the analytes in a non-uniform manner increasing the peak resolution and permitting analyses with detection limits of 1.6 {+-} 0.1 nM and 1.6 {+-} 0.2 nM, respectively.

  11. Direct fluorination of melatonin and 5-hydroxy-L-tryptophan with [18F]F2

    International Nuclear Information System (INIS)

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

    1986-01-01

    In order that melatonin receptors may be studied in man with positron emission tomography, melatonin labelled with a positron emitting isotope is needed. The preparation of 6-fluoro-melatonin labelled with F-18 is described. Using the same fluorination method, 5-hydroxy-6-(F-18)fluorotryptophan and 4-(F-18)fluoro-5-hydroxy-tryptophan were also prepared. (UK)

  12. Synthesis of 2-substituted tryptophans via a C3- to C2-alkyl migration

    Directory of Open Access Journals (Sweden)

    Michele Mari

    2014-08-01

    Full Text Available The reaction of 3-substituted indoles with dehydroalanine (Dha derivatives under Lewis acid-mediated conditions has been investigated. The formation of 2-substituted tryptophans is proposed to occur through a selective alkylative dearomatization–cyclization followed by C3- to C2-alkyl migration and rearomatization.

  13. Tryptophan catabolism restricts IFN-γ-expressing neutrophils and Clostridium difficile immunopathology

    NARCIS (Netherlands)

    El-Zaatari, Mohamad; Chang, Yu-Ming; Zhang, Min; Franz, Matthew; Shreiner, Andrew; McDermott, Andrew J.; van der Sluijs, Koenraad F.; Lutter, René; Grasberger, Helmut; Kamada, Nobuhiko; Young, Vincent B.; Huffnagle, Gary B.; Kao, John Y.

    2014-01-01

    The interplay between Clostridium difficile and the host's metabolome is believed to influence the severity of infection. However, the mechanism for this phenomenon remains unclear. In this study, we model one of these metabolic pathways by focusing on tryptophan metabolism in the host. We found

  14. Internal Energies of Ion-Sputtered Neutral Tryptophan and Thymine Molecules Determined by Vacuum Ultraviolet Photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jia; Takahashi, Lynelle; Wilson, Kevin R.; Leone, Stephen R.; Ahmed, Musahid

    2010-03-11

    Vacuum ultraviolet photoionization coupled to secondary neutral mass spectrometry (VUV-SNMS) of deposited tryptophan and thymine films are performed at the Chemical Dynamics Beamline. The resulting mass spectra show that while the intensity of the VUV-SNMS signal is lower than the corresponding secondary ion mass spectroscopy (SIMS) signal, the mass spectra are significantly simplified in VUV-SNMS. A detailed examination of tryptophan and thymine neutral molecules sputtered by 25 keV Bi3 + indicates that the ion-sputtered parent molecules have ~;;2.5 eV of internal energy. While this internal energy shifts the appearance energy of the photofragment ions for both tryptophan and thymine, it does not change the characteristic photoionizaton efficiency (PIE) curves of thymine versus photon energy. Further analysis of the mass spectral signals indicate that approximately 80 neutral thymine molecules and 400 tryptophan molecules are sputtered per incident Bi3 + ion. The simplified mass spectra and significant characteristic ion contributions to the VUV-SNMS spectra indicate the potential power of the technique for organic molecule surface analysis.

  15. Reprint of 'pH tuning of Nafion for selective detection of tryptophan'

    International Nuclear Information System (INIS)

    Frith, K.-A.; Limson, J.L.

    2010-01-01

    Selective and sensitive detection of the amino acid tryptophan is of importance in food processing, pharmaceutical formulations and in biological fluids. Electrochemical methods of detection of tryptophan are hampered by sluggish electron transfer kinetics and in complex matrices through overlapping peaks from interferents. This study examines the potential of the cation exchange membrane Nafion to enhance selectivity and sensitivity of this analyte through a seldom explored feature of this membrane: pH manipulation. A detailed examination of the effect of pH on the selectivity afforded by Nafion as a function of the analyte charge is presented. Selective detection of tryptophan and significant increases in sensitivity of its detection was observed in the presence of melatonin, dopamine and other interferents present in a pharmaceutical formulation through manipulation of the pH of the solution. At pH 3.0 at a Nafion-modified electrode, changes in the protonation of melatonin and tryptophan lowered the anodic potential of the analytes in a non-uniform manner increasing the peak resolution and permitting analyses with detection limits of 1.6 ± 0.1 nM and 1.6 ± 0.2 nM, respectively.

  16. Study of interaction between tryptophan, tyrosine, and phenylalanine separately with silver nanoparticles by fluorescence quenching method

    International Nuclear Information System (INIS)

    Roy, S.; Das, T.K.

    2015-01-01

    Using the spectroscopic method, the individual interaction of the three biochemically important amino acids, which are constituents of protein, namely, tryptophan, tyrosine, and phenylalanine with biologically synthesized silver nanoparticles has been investigated. The obtained UV-Vis spectra show the formation of ground-state complexes between tryptophan, tyrosine, and phenylalanine with silver nanoparticles. Silver nanoparticles possess the ability to quench the intrinsic fluorescence of the aforesaid amino acids by a dynamic quenching process. The binding constant, number of binding sites, and corresponding thermodynamic parameters (ΔH, ΔS, and ΔG) based on the interaction system were calculated for 293, 303, and 313 K. In the case of tryptophan and phenylalanine, with increase in temperature, the binding constant K was found to decrease; conversely, it was found to increase with increase in temperature in the case of tyrosine. The thermodynamic results revealed that the binding process was spontaneous; hydrogen bonding and van der Waals interaction were the predominant forces responsible for the complex stabilization in the case of tryptophan and phenylalanine, respectively, whereas in the case of tyrosine, hydrophobic interaction was the sole force conferring stability. Moreover, the Förster non-radiation energy transfer theory has been applied to calculate the average binding distance among the above amino acids and silver nanoparticles. The results show a binding distance of <7 nm, which ensures that energy transfer does occur between the said amino acids and silver nanoparticles. (authors)

  17. Cross-linking of lens crystallin proteins induced by tryptophan metabolites and metal ions

    DEFF Research Database (Denmark)

    Tweeddale, Helen J; Hawkins, Clare Louise; Janmie, Joane F

    2016-01-01

    Long-wavelength solar UV radiation is implicated in photodamage to the human eye. The human lens contains multiple tryptophan-derived compounds that have significant absorbance bands in the UVA region (λ 315-400 nm) that act as efficient physical filters for these wavelengths. The concentrations...

  18. Fluorescence imaging of tryptophan and collagen cross-links to evaluate wound closure ex vivo

    Science.gov (United States)

    Wang, Ying; Ortega-Martinez, Antonio; Farinelli, Bill; Anderson, R. R.; Franco, Walfre

    2016-02-01

    Wound size is a key parameter in monitoring healing. Current methods to measure wound size are often subjective, time-consuming and marginally invasive. Recently, we developed a non-invasive, non-contact, fast and simple but robust fluorescence imaging (u-FEI) method to monitor the healing of skin wounds. This method exploits the fluorescence of native molecules to tissue as functional and structural markers. The objective of the present study is to demonstrate the feasibility of using variations in the fluorescence intensity of tryptophan and cross-links of collagen to evaluate proliferation of keratinocyte cells and quantitate size of wound during healing, respectively. Circular dermal wounds were created in ex vivo human skin and cultured in different media. Two serial fluorescence images of tryptophan and collagen cross-links were acquired every two days. Histology and immunohistology were used to validate correlation between fluorescence and epithelialization. Images of collagen cross-links show fluorescence of the exposed dermis and, hence, are a measure of wound area. Images of tryptophan show higher fluorescence intensity of proliferating keratinocytes forming new epithelium, as compared to surrounding keratinocytes not involved in epithelialization. These images are complementary since collagen cross-links report on structure while tryptophan reports on function. HE and immunohistology show that tryptophan fluorescence correlates with newly formed epidermis. We have established a fluorescence imaging method for studying epithelialization processes during wound healing in a skin organ culture model, our approach has the potential to provide a non-invasive, non-contact, quick, objective and direct method for quantitative measurements in wound healing in vivo.

  19. Tryptophan Depletion Promotes Habitual over Goal-Directed Control of Appetitive Responding in Humans.

    Science.gov (United States)

    Worbe, Yulia; Savulich, George; de Wit, Sanne; Fernandez-Egea, Emilio; Robbins, Trevor W

    2015-02-05

    Optimal behavioral performance results from a balance between goal-directed and habitual systems of behavioral control, which are modulated by ascending monoaminergic projections. While the role of the dopaminergic system in behavioral control has been recently addressed, the extent to which changes in global serotonin neurotransmission could influence these 2 systems is still poorly understood. We employed the dietary acute tryptophan depletion procedure to reduce serotonin neurotransmission in 18 healthy volunteers and 18 matched controls. We used a 3-stage instrumental learning paradigm that includes an initial instrumental learning stage, a subsequent outcome-devaluation test, and a slip-of-action stage, which directly tests the balance between hypothetical goal-directed and habitual systems. We also employed a separate response inhibition control test to assess the behavioral specificity of the results. Acute tryptophan depletion produced a shift of behavioral performance towards habitual responding as indexed by performance on the slip-of-action test. Moreover, greater habitual responding in the acute tryptophan depletion group was predicted by a steeper decline in plasma tryptophan levels. In contrast, acute tryptophan depletion left intact the ability to use discriminative stimuli to guide instrumental choice as indexed by the instrumental learning stage and did not impair inhibitory response control. The major implication of this study is that serotonin modulates the balance between goal-directed and stimulus-response habitual systems of behavioral control. Our findings thus imply that diminished serotonin neurotransmission shifts behavioral control towards habitual responding. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  20. Effects of tryptophan derivatives and β-carboline alkaloids on radiation- and peroxide-induced transformations of ethanol

    International Nuclear Information System (INIS)

    Sverdlov, R.L.; Brinkevich, S.D.; Shadyro, O.I.

    2014-01-01

    The subject of this study was investigation of interactions of tryptophan and its derivatives, including structurally related β-carboline alkaloids with oxygen- and carbon-centered radicals being formed during radiation- and peroxide-induced transformations of ethanol. It was shown that the above named compounds suppressed recombination and disproportionation reactions of α-hydroxyethyl radicals. The inhibitory effects of tryptophan, 5-hydroxytryptophan and serotonin were mainly realized by means of reduction and addition reactions, while those of β-carboline alkaloids – harmine, harmane and harmaline – were due to oxidation reactions. Melatonin displayed low reactivity towards α-hydroxyethyl radicals. Tryptophan derivatives and β-carboline alkaloids were found to inhibit radiation-induced oxidation of ethanol while being virtually not used up. The low transformation yields of tryptophan, 5-hydroxytryptophan and serotonin, as well as β-carboline alkaloids, indicate their capability of regeneration, which could occur on interaction of tryptophan with O ·− 2 and HO · 2 , or on oxidation of α-hydroxyethyl radicals by β-carboline alkaloids. - Highlights: • Tryptophan, 5-hydroxytryptophane and serotonin can reduce or add α-HER. • β-Carboline alkaloids – harmane, harmine, harmaline – can oxidize α-HER. • Tryptophan and its derivatives can reduce oxygen-centered radicals

  1. Uptake and incorporation of labeled tryptophan isomers into IAA in the jsR1 mutant of Lemna gibba

    International Nuclear Information System (INIS)

    Baldi, B.G.; Maher, B.R.; Cohen, J.D.

    1989-01-01

    Analyses of the IAA-overproducing mutant of Lemna have been initiated in order to study in vivo biosynthesis of IAA. Using radiolabelled tryptophan isomers prepared from commercial sources of 14 C-D,L tryptophan by chiral separation kinetics of uptake of L and D tryptophan were determined for sterile cultures of individual jsR 1 four-frond colonies. Over a 24 h period, about 50% of the radioactivity from 14 C-L-TRP in media, or about 25% from 14 C-D-TRP, was found in the plant tissue. Maximal rates of uptake were seen in the first six hors for both isomers. Endogenous levels of tryptophan determined in jsR 1 as measures of pool sizes in vivo show 5 to 10 ug/g FW total tryptophan with less than 1% in the D isomer form. Information on uptake and endogenous pool sizes of tryptophan isomers is being used for feeding of stable isotope labeled tryptophan ( 13 C, 14 N) to jsR 1 at physiological levels. Analyses of incorporation of label into IAA using GC-MS and high resolution mass spectrometry are currently underway

  2. N-acetyl-L-tryptophan, a substance-P receptor antagonist attenuates aluminum-induced spatial memory deficit in rats.

    Science.gov (United States)

    Fernandes, Joylee; Mudgal, Jayesh; Rao, Chamallamudi Mallikarjuna; Arora, Devinder; Basu Mallik, Sanchari; Pai, K S R; Nampoothiri, Madhavan

    2018-06-01

    Neuroinflammation plays an important role in the pathophysiology of Alzheimer's disease. Neurokinin substance P is a key mediator which modulates neuroinflammation through neurokinin receptor. Involvement of substance P in Alzheimer's disease is still plausible and various controversies exist in this hypothesis. Preventing the deleterious effects of substance P using N-acetyl-L-tryptophan, a substance P antagonist could be a promising therapeutic strategy. This study was aimed to evaluate the effect of N-acetyl-L-tryptophan on aluminum induced spatial memory alterations in rats. Memory impairment was induced using aluminum chloride (AlCl 3 ) at a dose of 10 mg/kg for 42 d. After induction of dementia, rats were exposed to 30 and 50 mg/kg of N-acetyl-L-tryptophan for 28 d. Spatial memory alterations were measured using Morris water maze. Acetylcholinesterase activity and antioxidant enzyme glutathione level were assessed in hippocampus, frontal cortex and striatum. The higher dose of N-acetyl-L-tryptophan (50 mg/kg) significantly improved the aluminum induced memory alterations. N-acetyl-L-tryptophan exposure resulted in significant increase in acetylcholinesterase activity and glutathione level in hippocampus. The neuroprotective effect of N-acetyl-L-tryptophan could be due to its ability to block substance P mediated neuroinflammation, reduction in oxidative stress and anti-apoptotic properties. To conclude, N-acetyl-L-tryptophan may be considered as a novel neuroprotective therapy in Alzheimer's disease.

  3. Relation of plasma tryptophan concentrations during pregnancy to maternal sleep and mental well-being: The GUSTO cohort.

    Science.gov (United States)

    van Lee, Linde; Cai, Shirong; Loy, See Ling; Tham, Elaine K H; Yap, Fabian K P; Godfrey, Keith M; Gluckman, Peter D; Shek, Lynette P C; Teoh, Oon Hoe; Goh, Daniel Y T; Tan, Kok Hian; Chong, Yap Seng; Meaney, Michael J; Chen, Helen; Broekman, Birit F P; Chong, Mary F F

    2018-01-01

    Evidence suggests a relation between plasma tryptophan concentrations and sleep and mental well-being. As no studies have been performed in pregnant women, we studied the relation of plasma tryptophan concentrations during pregnancy with sleep quality, and mood during and after pregnancy. Pregnant women (n = 572) from the Growing Up in Singapore Towards healthy Outcomes study completed the Pittsburgh Sleep Quality Index (PSQI), the Edinburgh Postnatal Depression Scale (EPDS) and the State-Trait Anxiety Inventory (STAI) at 26-28 weeks gestation and three months post-delivery. Plasma tryptophan concentrations were measured at 26-28 weeks gestation. Poisson regressions estimated prevalence ratios (PR) for the association between tryptophan and poor sleep quality (PSQI global score > 5), probable antenatal depression (EPDS ≥ 15) and probable anxiety (STAI-state ≥ 41) were calculated adjusting for covariates. Mean plasma tryptophan concentrations was 48.0µmol/L (SD: 8.09). Higher plasma tryptophan concentrations were associated with a lower prevalence of antenatal poor sleep quality adjusting for covariates [PR: 0.88 (95% CI 0.80, 0.97) per 10µmol/L], especially in those participants who also suffered from anxiety symptoms [PR: 0.80 (95% CI 0.67, 0.95)]. No associations were observed between tryptophan concentrations during pregnancy and postnatal sleep quality or mental well-being. Subjective measures were used to assess sleep and mental well-being. We observed that higher plasma tryptophan concentrations were associated with a 12% lower prevalence of poor sleep quality during pregnancy, in particular among those with anxiety symptoms. These findings suggest the importance of having adequate tryptophan concentrations during pregnancy. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Thirteen week toxicity study of dietary l-tryptophan in rats with a recovery period of 5 weeks.

    Science.gov (United States)

    Shibui, Yusuke; Matsumoto, Hideki; Masuzawa, Yoko; Ohishi, Takumi; Fukuwatari, Tsutomu; Shibata, Katsumi; Sakai, Ryosei

    2018-04-01

    Although l-tryptophan is nutritionally important and widely used in medical applications, toxicity data for its oral administration are limited. The purpose of this study was to evaluate the potential toxicity of an experimental diet containing added l-tryptophan at doses of 0 (basal diet), 1.25%, 2.5% and 5.0% when administered to Sprague-Dawley rats for 13 weeks. There were no toxicological changes in clinical signs, ophthalmology, urinalysis, hematology, necropsy, organ weight and histopathology between control rats and those fed additional l-tryptophan. Body weight gain and food consumption significantly decreased throughout the administration period in males in the 2.5% group and in both sexes in the 5.0% group. At the end of the dosing period, decreases in water intake in males in the 5.0% group and in serum glucose in females in the 5.0% group were observed. The changes described above were considered toxicologically significant; however, they were not observed after a 5 week recovery period, suggesting reversibility. Consequently, the no-observed-adverse-effect level of l-tryptophan in the present study was 1.25% for males and 2.5% for females (mean intake of l-tryptophan: 779 mg kg -1 body weight day -1 [males] and 1765 mg kg -1 body weight day -1 [females]). As the basal diet used in this study contained 0.27% of proteinaceous l-tryptophan, the no-observed-adverse-effect level of overall l-tryptophan was 1.52% for males and 2.77% for females (mean intake of overall l-tryptophan: 948 mg kg -1 body weight day -1 (males) and 1956 mg kg -1 body weight day -1 (females)). We conclude that l-tryptophan has a low toxicity profile in terms of human use. Copyright © 2017 John Wiley & Sons, Ltd.

  5. The Effects of Tryptophan on Everyday Interpersonal Encounters and Social Cognitions in Individuals with a Family History of Depression.

    Science.gov (United States)

    Hogenelst, Koen; Schoevers, Robert A; Aan Het Rot, Marije

    2015-03-02

    Individuals with a family history of depression show subtle abnormalities in the processing of social stimuli. This could negatively affect their interpersonal functioning and contribute to their depression risk. Repeated administration of the serotonin precursor tryptophan has previously been shown to increase agreeable behavior and reduce quarrelsome behavior in irritable people, who are also considered at risk for depression. To examine the effects of tryptophan on social functioning in individuals with a family history of depression, 40 men and women with at least one first-degree relative with depression received tryptophan (1g three times a day) and placebo for 14 days each in a double-blind crossover design and recorded their social behavior and mood during everyday interpersonal encounters. Participants also provided daily ratings of their positive and negative cognitions concerning their social functioning. Tryptophan improved mood. Unexpectedly, tryptophan increased quarrelsome behavior and reduced agreeable behavior, specifically during interactions at home. The behavioral effects of tryptophan were not moderated by mood or by the interaction partner. Negative social cognitions were lower when tryptophan was given second and lower during placebo when placebo was given second. Overall, tryptophan may not alter social behavior in individuals with a family history of depression as it does in irritable people. However, the behavioral effects of tryptophan at home might be seen as a way for individuals with a family history of depression to achieve more control. Over time, this may positively influence the way they feel and think about themselves in a social context. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  6. Single histidine residue in head-group region is sufficient to impart remarkable gene transfection properties to cationic lipids: evidence for histidine-mediated membrane fusion at acidic pH.

    Science.gov (United States)

    Kumar, V V; Pichon, C; Refregiers, M; Guerin, B; Midoux, P; Chaudhuri, A

    2003-08-01

    Presence of endosome-disrupting multiple histidine functionalities in the molecular architecture of cationic polymers, such as polylysine, has previously been demonstrated to significantly enhance their in vitro gene delivery efficiencies. Towards harnessing improved transfection property through covalent grafting of endosome-disrupting single histidine functionality in the molecular structure of cationic lipids, herein, we report on the design, the synthesis and the transfection efficiency of two novel nonglycerol-based histidylated cationic amphiphiles. We found that L-histidine-(N,N-di-n-hexadecylamine)ethylamide (lipid 1) and L-histidine-(N,N-di-n-hexadecylamine,-N-methyl)ethylamide (lipid 2) in combination with cholesterol gave efficient transfections into various cell lines. The transfection efficiency of Chol/lipid 1 lipoplexes into HepG2 cells was two order of magnitude higher than that of FuGENE(TM)6 and DC-Chol lipoplexes, whereas it was similar into A549, 293T7 and HeLa cells. A better efficiency was obtained with Chol/lipid 2 lipoplexes when using the cytosolic luciferase expression vector (pT7Luc) under the control of the bacterial T7 promoter. Membrane fusion activity measurements using fluorescence resonance energy transfer (FRET) technique showed that the histidine head-groups of Chol/lipid 1 liposomes mediated membrane fusion in the pH range 5-7. In addition, the transgene expression results using the T7Luc expression vector convincingly support the endosome-disrupting role of the presently described mono-histidylated cationic transfection lipids and the release of DNA into the cytosol. We conclude that covalent grafting of a single histidine amino acid residue to suitable twin-chain hydrophobic compounds is able to impart remarkable transfection properties on the resulting mono-histidylated cationic amphiphile, presumably via the endosome-disrupting characteristics of the histidine functionalities.

  7. A Brief Historic Overview of Clinical Disorders Associated with Tryptophan: The Relevance to Chronic Fatigue Syndrome (CFS and Fibromyalgia (FM.

    Directory of Open Access Journals (Sweden)

    Adele Blankfield

    2012-01-01

    Full Text Available Last century there was a short burst of interest in the tryptophan related disorders of pellagra and related abnormalities that are usually presented in infancy. 1 , 2 Nutritional physiologists recognized that a severe human dietary deficiency of either tryptophan or the B group vitamins could result in central nervous system (CNS sequelae such as ataxia, cognitive dysfunction and dysphoria, accompanied by skin hyperpigmentation. 3 , 4 The current paper will focus on the emerging role of tryptophan in chronic fatigue syndrome (CFS and fibromyalgia (FM.

  8. Myocardial blood flow rate and capillary permeability for 99mTc-DTPA in patients with angiographically normal coronary arteries. Evaluation of the single-injection, residue detection method with intracoronary indicator bolus injection and the use of a mobile gamma camera

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Kelbaek, H; Efsen, F

    1994-01-01

    The aims of the present study were to quantitate myocardial perfusion and capillary permeability in the human heart by means of the single-injection, residue detection method using a mobile gamma camera. With this method, the intravascular mean transit time and the capillary extraction fraction (E...

  9. Etiological classification of depression based on the enzymes of tryptophan metabolism.

    Science.gov (United States)

    Fukuda, Katsuhiko

    2014-12-24

    Viewed in terms of input and output, the mechanisms of depression are still akin to a black box. However, there must be main pivots for diverse types of depression. From recent therapeutic observations, both the serotonin (5-HT) and kynurenine pathways of tryptophan metabolism may be of particular importance to improved understanding of depression. Here, I propose an etiological classification of depression, based on key peripheral and central enzymes of tryptophan metabolism. Endogenous depression is caused by a larger genetic component than reactive depression. Besides enterochromaffin and mast cells, tryptophan hydroxylase 1 (TPH1), primarily expressed in the gastrointestinal tract, is also found in 5-hydroxytryptophan-producing cells (5-HTP cells) in normal intestinal enterocytes, which are thought to essentially shunt 5-HT production in 5-HT-producing cells. Genetic studies have reported an association between TPH1 and depression, or the responsiveness of depression to antidepressive medication. Therefore, it is possible that hypofunctional 5-HTP cells (reflecting TPH1 dysfunction) in the periphery lead to deficient brain 5-HT levels. Additionally,it has been reported that higher TPH2 expression in depressed suicides may reflect a homeostatic response to deficient 5-HT levels. Subsequently, endogenous depression may be caused by TPH1 dysfunction combined with compensatory TPH2 activation. Reactive depression results from life stresses and involves the hypothalamic-pituitary-adrenal axis, with resulting cortisol production inducing tryptophan 2,3-dioxygenase (TDO) activation. In secondary depression, caused by inflammation, infection, or oxidative stress, indoleamine 2,3-dioxygenase (IDO) is activated. In both reactive and secondary depression, the balance between 3-hydroxykynurenine (3-HK) and kynurenic acid may shift towards 3-HK production via kynurenine-3-monooxygenase (KMO) activation. By shifting the equilibrium position of key enzymes of tryptophan

  10. Effect of tryptophan hydroxylase gene polymorphism on aggression in major depressive disorder and undifferentiated somatoform disorder.

    Science.gov (United States)

    Koh, Kyung Bong; Kim, Chan Hyung; Choi, Eun Hee; Lee, Young-joon; Seo, Won Youl

    2012-05-01

    Aggression and anger have been linked with depression, and anger suppression has been linked with somatic symptoms of somatoform disorders. However, the relationship between aggression or anger and genes in patients with depression and somatoform disorders has not been clearly elucidated. The objective of this study was to examine the effect of serotonin-related gene polymorphism on aggression in depressive disorders and somatoform disorders. A serotonin-related polymorphic marker was assessed by using single nucleotide polymorphism (SNP) genotyping. 106 outpatients with major depressive disorder (MDD), 102 outpatients with undifferentiated somatoform disorder, and 133 healthy subjects were enrolled between October 2005 and May 2008. Diagnoses were made according to the Korean version of the Structured Clinical Interview Schedule for DSM-IV. The allele and genotype frequencies of tryptophan hydroxylase-1 (TPH1) A218C were compared between groups. The Hamilton Depression Rating Scale and the Aggression Questionnaire were used for psychological assessment. Each of the 2 disorder groups scored significantly higher on all the Aggression Questionnaire subscales and on the total Aggression Questionnaire score than the healthy subjects (P sex and age. However, no significant differences were found in TPH1 C allele and CC homozygote frequencies between the undifferentiated somatoform disorder patients and the healthy subjects. TPH1 CC homozygote in the MDD group scored significantly higher in terms of verbal aggression (P = .03) and total Aggression Questionnaire score (P = .04) than A-carrier genotypes, regardless of sex and age. However, no significant differences were found in the scores of all the Aggression Questionnaire subscales and the total Aggression Questionnaire score between TPH1 CC homozygote and A-carrier genotypes in the undifferentiated somatoform disorder group and the control group, respectively. Aggression in MDD patients is more susceptible to an

  11. Involvement of tryptophan hydroxylase 2 gene polymorphisms in susceptibility to tic disorder in Chinese Han population

    Directory of Open Access Journals (Sweden)

    Zheng Ping

    2013-01-01

    Full Text Available Abstract Background Tryptophan hydroxylase-2 (TPH2 is a potential candidate gene for screening tic disorder (TD. Methods A case–control study was performed to examine the association between the TPH2 gene and TD. The Sequenom® Mass ARRAY iPLEX GOLD System was used to genotype two single nucleotide polymorphisms (SNPs of the TPH2 gene in 149 TD children and in 125 normal controls. Results For rs4565946, individuals with the TT genotype showed a significantly higher risk of TD than those with TC plus CC genotypes [odds ratio (OR =3.077, 95% confidence interval (CI: 1.273–7.437; P = 0.009], as did male TD children with the TT genotype (OR = 3.228, 95% CI: 1.153–9.040; P = 0.020. The G allele of rs4570625 was significantly more frequent in TD children with higher levels of tic symptoms (Yale Global Tic Severity Scale, YGTSS than those in controls among the male children (OR = 1.684, 95%: 1.097–2.583; P = 0.017]. TD children with severe tic symptoms had significantly higher frequencies of rs4546946 TT genotype than did normal controls in boys (OR = 3.292, 95% CI: 1.139–9.513; P = 0.022. We also found that genotype distributions of both SNPs were different between the Asian and European populations. Conclusions Our results indicated that the TT genotype of rs4565946 is a potential genetic risk factor for TD, and the allele G of rs4570625 might be associated with the severity of tic symptoms in boys. These polymorphisms might be susceptibility loci for TD in the Chinese Han population. Because of the confounding of co-existing attention deficit hyperactivity disorder (ADHD,these findings need to be confirmed by studies in much larger samples.

  12. The Effects of Tryptophan on Everyday Interpersonal Encounters and Social Cognitions in Individuals with a Family History of Depression

    NARCIS (Netherlands)

    Hogenelst, Koen; Schoevers, Robert A.; Rot, Marije Aan Het

    2015-01-01

    Background: Individuals with a family history of depression show subtle abnormalities in the processing of social stimuli. This could negatively affect their interpersonal functioning and contribute to their depression risk. Repeated administration of the serotonin precursor tryptophan has

  13. Cognition following acute tryptophan depletion : Difference between first-degree relatives of bipolar disorder patients and matched healthy control volunteers

    NARCIS (Netherlands)

    Sobczak, S; Riedel, W J; Booij, I; Aan Het Rot, M; Deutz, N E P; Honig, A

    BACKGROUND: Serotonergic circuits have been proposed to mediate cognitive processes, particularly learning and memory. Cognitive impairment is often seen in bipolar disorders in relation to a possible lowered serotonergic turnover. METHODS: We investigated the effects of acute tryptophan depletion

  14. Reduction of cerebral blood flow in subclinical hepatic encephalopathy and its correlation with plasma-free tryptophan

    International Nuclear Information System (INIS)

    Rodriguez, G.; Testa, R.; Celle, G.; Gris, A.; Marenco, S.; Nobili, F.; Novellone, G.; Rosadini, G.

    1987-01-01

    Cerebral blood flow (CBF), measured by the noninvasive xenon-133 inhalation method, EEG, and plasma levels of ammonia (NH 3 ) and free tryptophan were determined in 18 hospitalized cirrhotic patients affected with subclinical hepatic encephalopathy, as diagnosed by the Kurtz test. CBF results were significantly lower (p less than 0.001) in the patients' group as compared with a sex- and age-matched normal control population, although seven patients had values in the normal range. NH 3 was increased only in six, while free tryptophan was increased in all but two patients. A significant negative correlation (p = 0.02) between CBF and free tryptophan was found, even though it appears to be difficult to interpret. We suggest that CBF impairment in some cirrhotic patients with subclinical hepatic encephalopathy may be related to the systemic metabolic derangement caused by the liver disease; free tryptophan could have some implication in producing CBF reduction

  15. Membrane interaction and secondary structure of de novo designed arginine-and tryptophan peptides with dual function

    KAUST Repository

    Rydberg, Hanna A.; Carlsson, Nils; Nordé n, Bengt

    2012-01-01

    of arg/trp peptides and investigated how the position and number of tryptophans affect cellular uptake. Here we explore the antimicrobial properties and the interaction with lipid model membranes of these peptides, using minimal inhibitory concentrations

  16. Metabolism of carbon-14 labelled l-tryptophan, l-kynerenine and hydroxy-l-kynerenine in miners with scleroderma

    International Nuclear Information System (INIS)

    Hankes, L.V.; De Bruin, E.; Jansen, C.R.; Voster, L.; Schmaeler, M.

    1977-01-01

    Six South African white miners were studied with the 2-g l-tryptophan load test and tracer doses of L-tryptophan-7a-carbon-14, L-kynurenine-keto-carbon-14 and hydroxy-L-kynerenine-keto-carbon-14. The breath 14 CO 2 and 14 urinary metabolites were measured. When they were compared with a previous study of American women with scleroderma, similar 14 CO 2 and tryptophan metabolite excretion patterns were observed in the data from the miners. The labelled quinolinic acid excretion was more significantly elevated in the South African miners' urine than in the urine of the American women. The data from both studies suggest that some patients with scleroderma have an altered step in the tryptophan metabolic pathway after hydroxy-anthranilic acid. What relationship exists between the induction of pulmonary silicosis and the subsequent development of scleroderma, requires additional human studies

  17. Tryptophan-Assisted Synthesis Reduces Bimetallic Gold/Silver Nanoparticle Cytotoxicity and Improves Biological Activity

    Directory of Open Access Journals (Sweden)

    Igor O. Shmarakov

    2014-10-01

    Full Text Available Aiming to reduce the potential in vivo hepato-and nephrotoxicity of Ag/Au bimetallic nanoparticles (NPs stabilized by sodium dodecyl sulphate (SDS, an approach involving a simultaneous reduction of silver nitrate and tetrachlorauratic acid using tryptophan (Trp as a reducing/stabilizing agent was applied during NP synthesis. The obtained Ag/Au/Trp NPs (5–15 nm sized were able to form stable aggregates with an average size of 370–450 nm and were potentially less toxic than Ag/Au/SDS in relation to a mouse model system based on clinical biochemical parameters and oxidative damage product estimation. Ag/Au/Trp NPs were shown to exhibit anticancer activity in relation to a Lewis lung carcinoma model. The data generated from the present study support the fact that the use of tryptophan in NP synthesis is effective in attenuating the potential hepatotoxicity and nephrotoxicity of NPs during their in vivo application.

  18. Effects of biogenic aldehydes and aldehyde dehydrogenase inhibitors on rat brain tryptophan hydroxylase activity in vitro.

    Science.gov (United States)

    Nilsson, G E; Tottmar, O

    1987-04-21

    The effect of indole-3-acetaldehyde, 5-hydroxyindole-3-acetaldehyde, disulfiram, diethyldithiocarbamate, coprine, and 1-amino-cyclopropanol on tryptophan hydroxylase activity was studied in vitro using high performance liquid chromatography with electro-chemical detection. With the analytical method developed, 5-hydroxytryptophan, serotonin, and 5-hydroxyindole-3-acetic acid could be measured simultaneously. Indole-3-acetaldehyde (12-1200 microM) was found to cause a 6-33% inhibition of the enzyme. Dependent upon the nature of the sulfhydryl- or reducing-agent (dithiotreitol, glutathione, or ascorbate) present in the incubates, the degree of inhibition by disulfiram varied, probably due to the formation of various mixed disulfides. Also the presence of diethyldithiocarbamate (160-1600 microM) was found to inhibit tryptophan hydroxylase (28-91%), while 5-hydroxyindole-3-acetaldehyde, coprine, or 1-aminocyclopropanol appeared to have no effect on the enzyme activity.

  19. Enzymatic synthesis of S-phenyl-L-cysteine from keratin hydrolysis industries wastewater with tryptophan synthase.

    Science.gov (United States)

    Xu, Lisheng; Wang, Zhiyuan; Mao, Pingting; Liu, Junzhong; Zhang, Hongjuan; Liu, Qian; Jiao, Qing-Cai

    2013-04-01

    An economical method for production of S-phenyl-L-cysteine from keratin acid hydrolysis wastewater (KHW) containing L-serine was developed by recombinant tryptophan synthase. This study provides us with an alternative KHW utilization strategy to synthesize S-phenyl-L-cysteine. Tryptophan synthase could efficiently convert L-serine contained in KHW to S-phenyl-L-cysteine at pH 9.0, 40°C and Trion X-100 of 0.02%. In a scale up study, L-serine conversion rate reach 97.1% with a final S-phenyl-L-cysteine concentration of 38.6 g l(-1). Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Formation of tryptophan radicals in irradiated aqueous solutions of hexachloroplatinate(IV): a flash photolysis study.

    Science.gov (United States)

    Zang, L; Rodgers, M A

    1999-10-01

    The oxidation of tryptophan photosensitized by PtCl6(2-) has been investigated in aqueous solutions at different pH using nanosecond laser flash photolysis. Cationic and neutral radicals of tryptophan were detected at pH 2.8 and 8.5, respectively. The generation of the radical was attributed to oxidation by Cl2- that was formed from the homolytic bond cleavage in the excited state of PtCl6(2-). The bimolecular rate constant derived from the kinetics analysis, 2.8 +/- 0.2 x 10(9) M-1 s-1, is in good agreement with the value obtained in earlier pulse radiolysis studies. Both the cationic and neutral radicals decayed by second-order kinetics, consistent with the dimerization process.

  1. Enzymatic syntheses of some 11C-labelled analogues of L-tyrosine and L-tryptophan

    International Nuclear Information System (INIS)

    Bjurling, P.; Malmborg, P.; Langstroem, B.

    1990-01-01

    In the elucidation of biochemical processes by use of positron emission tomography (PET), the multi-tracer approach can be valuable. In previous work, the authors have been studying the dopaminergic and serotonergic neurosystems by use of 11 C-labelled L-DOPA and 5-hydroxy-L-tryptophan, respectively. They have now developed the syntheses of several analogues of tyrosine and tryptophan, labelled with 11 C in the β-position, which are of interest for use in similar applications

  2. Tryptophan-enriched antioxidant cereals improve sleep in children with autistic spectrum and attention deficit hyperactivity disorders

    OpenAIRE

    Galán, Carmen; Sánchez, Soledad; Franco, Lourdes; Bravo, Rafael; Rivero, Montserrat; Rodríguez, Ana Beatriz; Barriga, Carmen

    2017-01-01

    Theintake of foods rich in tryptophan produces beneficial effects on sleep. Themajority of children with neurological disorders like autistic spectrum disorder(ASD), cerebral palsy or attention deficit hyperactivity disorder (ADHD) havesleep problems. To evaluate the effect of tryptophan-enriched cereal intake onsleep of children with neurological disorders. Involving 7 children with ASD, 9children with cerebral palsy and 6 children with ADHD. They carried a wrist actimeterto record activity....

  3. Multiresponse optimization of a UPLC method for the simultaneous determination of tryptophan and 15 tryptophan-derived compounds using a Box-Behnken design with a desirability function.

    Science.gov (United States)

    Setyaningsih, Widiastuti; Saputro, Irfan E; Carrera, Ceferino A; Palma, Miguel; Barroso, Carmelo G

    2017-06-15

    A Box-Behnken design was used in conjunction with multiresponse optimization based on the desirability function to carry out the simultaneous separation of tryptophan and 15 derivatives by Ultra Performance Liquid Chromatography. The gradient composition of the mobile phase and the flow rate were optimized with respect to the resolution of severely overlapping chromatographic peaks and the total run time. Two different stationary phases were evaluated (hybrid silica and a solid-core-based C 18 column). The methods were validated and a suitable sensitivity was found for all compounds in the concentration range 1-100μgL -1 (R 2 >0.999). High levels of repeatability and intermediate precision (CV less than 0.25% and 1.7% on average for the retention time and the signal area, respectively) were obtained. The new method was applied to the determination tryptophan and its derivatives in black pigmented glutinous and non-glutinous rice grain samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Serum Levels of Tryptophan, 5-Hydroxytryptophan and Serotonin in Patients Affected with Different Forms of Amenorrhea

    Directory of Open Access Journals (Sweden)

    S. Comai

    2010-01-01

    Full Text Available Tryptophan (Trp is present in the serum, partly bound to albumine and in the free form. The unbound portion of circulating tryptophan has the property of crossing the hematoencephalic barrier and being converted within the brain into serotonin (5-HT through the enzymatic processes of hydroxylation and decarboxylation. The serotoninergic system plays an important role in neuroendocrine control of reproductive hormone secretion, and in particular, it may influence GnRH pulsatility, a function essential for reproductive processes. In this study, we analysed serum levels of tryptophan, serotonin and 5-hydroxytryptophan (5-HTP in women with three different forms of amenorrhea: 16 patients were diagnosed with anorexia nervosa, 60 patients with functional hypothalamic amenorrhea, and 14 patients with hyperprolactinemia. Data were compared with those of a group of 25 healthy women. Serum Trp levels were significantly (P ≤ 0.05 lower in the anorexic (11.64 ± 0.53 μg/ml, mean ± S.E. than in the control (12.98 ± 0.37 μg/ml groups. In addition, in the anorexic group a statistical dispersion of Trp values was shown indicating a bimodal data distribution suggesting the existence of two different subgroups of patients. Regarding 5-HTP, an increase of its serum level was observed in all the groups with amenorrhea with the highest value in hyperprolactinemic patients. On the contrary, no statistical differences in serum 5-HT levels among the four analyzed groups were observed. This study shows that women affected by various forms of amenorrhea present an altered metabolism of tryptophan via serotonin and, in particular, markedly high differences are observed between the two subgroups of anorexic patients.

  5. Serum Levels of Tryptophan, 5-Hydroxytryptophan and Serotonin in Patients Affected with Different Forms of Amenorrhea

    Directory of Open Access Journals (Sweden)

    S. Comai

    2010-06-01

    Full Text Available Tryptophan (Trp is present in the serum, partly bound to albumine and in the free form. The unbound portion of circulating tryptophan has the property of crossing the hematoencephalic barrier and being converted within the brain into serotonin (5-HT through the enzymatic processes of hydroxylation and decarboxylation. The serotoninergic system plays an important role in neuroendocrine control of reproductive hormone secretion, and in particular, it may influence GnRH pulsatility, a function essential for reproductive processes. In this study, we analysed serum levels of tryptophan, serotonin and 5-hydroxytryptophan (5-HTP in women with three different forms of amenorrhea: 16 patients were diagnosed with anorexia nervosa, 60 patients with functional hypothalamic amenorrhea, and 14 patients with hyperprolactinemia. Data were compared with those of a group of 25 healthy women. Serum Trp levels were significantly (P ≤ 0.05 lower in the anorexic (11.64 ± 0.53 µg/ml, mean ± S.E. than in the control (12.98 ± 0.37 µg/ml groups. In addition, in the anorexic group a statistical dispersion of Trp values was shown indicating a bimodal data distribution suggesting the existence of two different subgroups of patients. Regarding 5-HTP, an increase of its serum level was observed in all the groups with amenorrhea with the highest value in hyperprolactinemic patients. On the contrary, no statistical differences in serum 5-HT levels among the four analyzed groups were observed. This study shows that women affected by various forms of amenorrhea present an altered metabolism of tryptophan via serotonin and, in particular, markedly high differences are observed between the two subgroups of anorexic patients.

  6. Uremic anorexia: a consequence of persistently high brain serotonin levels? The tryptophan/serotonin disorder hypothesis.

    Science.gov (United States)

    Aguilera, A; Selgas, R; Codoceo, R; Bajo, A

    2000-01-01

    Anorexia is a frequent part of uremic syndrome, contributing to malnutrition in dialysis patients. Many factors have been suggested as responsible for uremic anorexia. In this paper we formulate a new hypothesis to explain the appetite disorders in dialysis patients: "the tryptophan/serotonin disorder hypothesis." We review current knowledge of normal hunger-satiety cycle control and the disorders described in uremic patients. There are four phases in food intake regulation: (1) the gastric phase, during which food induces satiety through gastric distention and satiety peptide release; (2) the post absorptive phase, during which circulating compounds, including glucose and amino acids, cause satiety by hepatic receptors via the vagus nerve; (3) the hepatic phase, during which adenosine triphosphate (ATP) concentration is the main stimulus inducing hunger or satiety, with cytokines inhibiting ATP production; and (4) the central phase, during which appetite is regulated through peripheral (circulating plasma substances and neurotransmitters) and brain stimuli. Brain serotonin is the final target for peripheral mechanisms controlling appetite. High brain serotonin levels and a lower serotonin/dopamine ratio cause anorexia. Plasma and brain amino acid concentrations are recognized factors involved in neurotransmitter synthesis and appetite control. Tryptophan is the substrate of serotonin synthesis. High plasma levels of anorectics such as tryptophan (plasma and brain), cholecystokinin, tumor necrosis factor alpha, interleukin-1, and leptin, and deficiencies of nitric oxide and neuropeptide Y have been described in uremia; all increase intracerebral serotonin. We suggest that brain serotonin hyperproduction due to a uremic-dependent excess of tryptophan may be the final common pathway involved in the genesis of uremic anorexia. Various methods of ameliorating anorexia by decreasing the central effects of serotonin are proposed.

  7. No Tryptophan, Tyrosine and Phenylalanine Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder

    OpenAIRE

    Bergwerff, C.E.; Luman, M.; Blom, H.J.; Oosterlaan, J.

    2016-01-01

    Background The aim of the current study was to explore the role of aromatic amino acids (AAAs) in blood in relation to attention-deficit/hyperactivity disorder (ADHD). Given their impact on the synthesis of serotonin and dopamine, decreased concentrations of the AAAs tryptophan, tyrosine and phenylalanine in blood may contribute to the expression of ADHD symptoms. Decreased AAA blood concentrations, in turn, may be related to lowered dietary protein intake or to abnormal AAA catabolism, as ev...

  8. Effects of Acute Tryptophan Depletion on Three Different Types of Behavioral Impulsivity

    Directory of Open Access Journals (Sweden)

    Donald M. Dougherty

    2010-01-01

    Full Text Available Introduction While central nervous system serotonin has been implicated in a variety of problematic impulsive behaviors, biological manipulation of brain serotonin using acute tryptophan depletion for studying changes in impulsive behavior has received little attention. Methods Using identical treatment conditions, we examined the effects of reduced serotonin synthesis for each of three matched groups using acute tryptophan depletion. Thirty healthy men and women (ages 18–45 were assigned to perform one of three tasks assessing different types of behavioral impulsivity: response initiation, response inhibition, and consequence sensitivity ( N = 90. Participants completed two experimental days during which each consumed either a tryptophan-depletion or balanced-placebo amino-acid formulation and completed 5 sessions of their respective tasks at 0.25 h before and 1.5, 4.0, 5.0, and 6.0 h after beverage consumption. Results During peak effectiveness (5.0 h to 6.0 h following amino-acid consumption, depletion produced selective differences dependent on the type of impulsivity being tested. Specifically, relative to baseline testing (pre-depletion, response initiation impulsivity was significantly increased during the peak effects of depletion. And, when compared to placebo control, both response initiation and consequence sensitivity impulsivity were increased during the peak effects of depletion. Conclusion Though response initiation and consequence sensitivity impulsivity were affected by tryptophan depletion, response inhibition impulsivity was not, suggesting that other biological processes may underlie this specific component of impulsivity. Future research in other populations or using different pharmacological agents is warranted to further examine the biological processes underlying these components of impulsivity.

  9. Effects of Acute Tryptophan Depletion on Three Different Types of Behavioral Impulsivity

    Directory of Open Access Journals (Sweden)

    Donald M. Dougherty

    2010-06-01

    Full Text Available Introduction: While central nervous system serotonin has been implicated in a variety of problematic impulsive behaviors, biological manipulation of brain serotonin using acute tryptophan depletion for studying changes in impulsive behavior has received little attention. Methods: Using identical treatment conditions, we examined the effects of reduced serotonin synthesis for each of three matched groups using acute tryptophan depletion. Thirty healthy men and women (ages 18–45 were assigned to perform one of three tasks assessing different types of behavioral impulsivity: response initiation, response inhibition, and consequence sensitivity (N = 90. Participants completed two experimental days during which each consumed either a tryptophan-depletion or balanced-placebo amino-acid formulation and completed 5 sessions of their respective tasks at 0.25 h before and 1.5, 4.0, 5.0, and 6.0 h after beverage consumption. Results: During peak effectiveness (5.0 h to 6.0 h following amino-acid consumption, depletion produced selective differences dependent on the type of impulsivity being tested. Specifically, relative to baseline testing (pre-depletion, response initiation impulsivity was significantly increased during the peak effects of depletion. And, when compared to placebo control, both response initiation and consequence sensitivity impulsivity were increased during the peak effects of depletion. Conclusion: Though response initiation and consequence sensitivity impulsivity were affected by tryptophan depletion, response inhibition impulsivity was not, suggesting that other biological processes may underlie this specific component of impulsivity. Future research in other populations or using different pharmacological agents is warranted to further examine the biological processes underlying these components of impulsivity.

  10. Leptogenesis and residual CP symmetry

    International Nuclear Information System (INIS)

    Chen, Peng; Ding, Gui-Jun; King, Stephen F.

    2016-01-01

    We discuss flavour dependent leptogenesis in the framework of lepton flavour models based on discrete flavour and CP symmetries applied to the type-I seesaw model. Working in the flavour basis, we analyse the case of two general residual CP symmetries in the neutrino sector, which corresponds to all possible semi-direct models based on a preserved Z 2 in the neutrino sector, together with a CP symmetry, which constrains the PMNS matrix up to a single free parameter which may be fixed by the reactor angle. We systematically study and classify this case for all possible residual CP symmetries, and show that the R-matrix is tightly constrained up to a single free parameter, with only certain forms being consistent with successful leptogenesis, leading to possible connections between leptogenesis and PMNS parameters. The formalism is completely general in the sense that the two residual CP symmetries could result from any high energy discrete flavour theory which respects any CP symmetry. As a simple example, we apply the formalism to a high energy S 4 flavour symmetry with a generalized CP symmetry, broken to two residual CP symmetries in the neutrino sector, recovering familiar results for PMNS predictions, together with new results for flavour dependent leptogenesis.

  11. Determination of C10-chloroalkane residues in fish matrices by short column gas chromatography/electron capture negative ion low resolution mass spectrometry applying single pure and representative synthesised chlorodecanes as standards

    International Nuclear Information System (INIS)

    Beaume, Florence; Coelhan, Mehmet; Parlar, Harun

    2006-01-01

    A new chlorodecane (CD) standard was developed consisting of five single compounds with 5-9 Cl-atoms, with which it was possible to determine chlorodecane residues in fish matrices from different countries using short column gas chromatography/electron capture negative ion low resolution mass spectrometry (SCGC/ECNI-LRMS). The concentrations found were between 4.8 and 30.2 ng/g fat. Pentachlorodecanes could not be detected in all samples. For an evaluation of the new CD-standard, the fish matrices were also quantified by several other polychlorinated decane (CP10) standards with different chlorine grade: 50, 55, 63.5, 65, and 70%. The concentrations found differed unsurprisingly considerable among the applied standards. Considering only these CP10:50-70% standards that showed the highest similarity in peak patterns with the fish samples, the differences in observed chlorodecane concentrations between these standards and the new CD-standard were low, varying only 1-16%. The CP10:50-70% standards were further quantified with the new CD-standard (chlorine content, 58.2%) with neglectable observed differences to the CP10:60, 63.5, and 65% standards. Highest differences were observed to the CP10:50, 55, and 70% standards. By this work, the quantification of eco-toxicologically relevant C10-chloroparaffins using the new CD-standard has led to reproducible and reliable results, which indicates further that these compounds are still a concerning class of substances in environmental fish samples

  12. Fourier transform coupled tryptophan scanning mutagenesis identifies a bending point on the lipid-exposed δM3 transmembrane domain of the Torpedo californica nicotinic acetylcholine receptor

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    Caballero-Rivera, Daniel; Cruz-Nieves, Omar A; Oyola-Cintrón, Jessica; Torres-Núñez, David A; Otero-Cruz, José D

    2011-01-01

    The nicotinic acetylcholine receptor (nAChR) is a member of a family of ligand-gated ion channels that mediate diverse physiological functions, including fast synaptic transmission along the peripheral and central nervous systems. Several studies have made significant advances toward determining the structure and dynamics of the lipid-exposed domains of the nAChR. However, a high-resolution atomic structure of the nAChR still remains elusive. In this study, we extended the Fourier transform coupled tryptophan scanning mutagenesis (FT-TrpScanM) approach to gain insight into the secondary structure of the δM3 transmembrane domain of the Torpedo californica nAChR, to monitor conformational changes experienced by this domain during channel gating, and to identify which lipid-exposed positions are linked to the regulation of ion channel kinetics. The perturbations produced by periodic tryptophan substitutions along the δM3 transmembrane domain were characterized by two-electrode voltage clamp and 125I-labeled α-bungarotoxin binding assays. The periodicity profiles and Fourier transform spectra of this domain revealed similar helical structures for the closed- and open-channel states. However, changes in the oscillation patterns observed between positions Val-299 and Val-304 during transition between the closed- and open-channel states can be explained by the structural effects caused by the presence of a bending point introduced by a Thr-Gly motif at positions 300–301. The changes in periodicity and localization of residues between the closed-and open-channel states could indicate a structural transition between helix types in this segment of the domain. Overall, the data further demonstrate a functional link between the lipid-exposed transmembrane domain and the nAChR gating machinery. PMID:21785268

  13. The role of adrenal hormones in the activation of tryptophan 2,3-dioxygenase by nicotinic acid in rat liver.

    Science.gov (United States)

    Sainio, E L

    1997-09-01

    In this study, our previous finding that nicotinic acid activates tryptophan 2,3-dioxygenase as strongly as tryptophan was investigated in further detail. This study focused on the role of the adrenals in the activation process. Adrenalectomy abolished the activation due to nicotinic acid, but not the activation caused by tryptophan. The role of corticoids and/or adrenomedullary hormones in the enzyme activation was studied, by supplementing these hormones in adrenalectomized rats using minipumps implanted under the skin. The results showed that the enhanced activity of tryptophan 2,3-dioxygenase caused by nicotinic acid was partly restored by adrenaline following adrenalectomy but not by corticosterone supplementation. The results were supported by further experiments in which the rats were treated with adrenaline or corticosterone intraperitoneally before nicotinic acid administration. The conclusion that adrenaline participates in the regulation of tryptophan 2,3-dioxygenase should promote further study to determine whether adrenaline is a general modulator of this enzyme. This experimental model generated new information on the activation mechanism of tryptophan 2,3-dioxygenase by nicotinic acid.

  14. l-Tryptophan Radical Cation Electron Spin Resonance Studies: Connecting Solution-derived Hyperfine Coupling Constants with Protein Spectral Interpretations

    Science.gov (United States)

    Connor, Henry D.; Sturgeon, Bradley E.; Mottley, Carolyn; Sipe, Herbert J.; Mason, Ronald P.

    2009-01-01

    Fast-flow electron spin resonance (ESR) spectroscopy has been used to detect a free radical formed from the reaction of l-tryptophan with Ce4+ in an acidic aqueous environment. Computer simulations of the ESR spectra from l-tryptophan and several isotopically modified forms strongly support the conclusion that the l-tryptophan radical cation has been detected by ESR for the first time. The hyperfine coupling constants (HFCs) determined from the well-resolved isotropic ESR spectra support experimental and computational efforts to understand l-tryptophan's role in protein catalysis of oxidation-reduction processes. l-tryptophan HFCs facilitated the simulation of fast-flow ESR spectra of free radicals from two related compounds, tryptamine and 3-methylindole. Analysis of these three compounds' β-methylene hydrogen HFC data along with equivalent l-tyrosine data has led to a new computational method that can distinguish between these two amino acid free radicals in proteins without dependence on isotope labeling, electron nuclear double resonance or high-field ESR. This approach also produces geometric parameters (dihedral angles for the β-methylene hydrogens) which should facilitate protein site assignment of observed l-tryptophan radicals as has been done for l-tyrosine radicals. PMID:18433127

  15. Alzheimer's disease evaluation using label-free, stainless, fluorescence to measure tryptophan metabolism along the kynurenine pathway

    Science.gov (United States)

    Sordillo, Laura A.; Zhang, Lin; Shi, Lingyan; Sriramoju, Vidyasagar; Sordillo, Peter P.; Alfano, Robert R.

    2018-02-01

    Under stress conditions, pro-inflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-1 beta, interleukin 6 and interferon gamma are released. It is known that these cytokines stimulate indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO), which increase tryptophan metabolism through the kynurenine pathway, and that this can cause increased production of neurotoxic compounds. Brain tissues from Alzheimer's disease patients and agematched controls were investigated using label-free fluorescence spectroscopy. Tryptophan (exc. 280/ em. 340 nm) and its metabolites (N-formyl-L-kynurenine (exc. 325/em. 434 nm), kynurenine (exc. 365/em. 480 nm) and kynurenic acid (exc. 330/em. 390 nm)) have distinct spectral profiles. Preliminary results show a difference in the optical signatures in three important areas of the brain (hippocampus, BA 9, BA 17) between patients with Alzheimer's disease and agedmatched controls (normal), and a marked relative increase in tryptophan in the Alzheimer's patients. Thus determinations of tryptophan to tryptophan metabolite ratios could potentially be used to measure IDO and TDO activity and the degree of inflammation in the brain. This label-free optical technique may be useful in the study of Alzheimer's and other neurodegenerative diseases.

  16. [Characterisation of three polymorphisms of the tryptophan hydroxylase 2 gene in a sample of Colombian population with major depressive disorder].

    Science.gov (United States)

    Martínez-Idárraga, Adriana; Riveros-Barrera, Irene; Sánchez, Ricardo; Jaramillo, Luis Eduardo; Calvo-Gómez, José Manuel; Yunis-Londoño, Juan José

    Identify whether rs11179000, rs136494 and rs4570625 polymorphisms of the tryptophan hydroxylase 2 gene, are associated with a major depressive disorder in a sample of the Colombian population. Case-control study was conducted in which a comparison was made between subjects diagnosed with major depressive disorder at some point in adulthood or active symptoms at the time of evaluation, and subjects with no psychiatric disease. Subjects were studied in the Department of Psychiatry, Faculty of Medicine and the Institute of Genetics at the National University of Colombia. Polymorphisms were genotyped using Taqman probes in real time PCR. As well as studying the association between major depressive disorder and these (single nucleotide polymorphisms (SNPs), the association with other factors previously associated with depression were also analysed. No statistically significant association between genotypic and allelic frequencies of each polymorphism and major depressive disorder was found. Association between sex and complication during pregnancy / childbirth and major depressive disorder was observed. Association between sex and complication during pregnancy / childbirth and major depressive disorder was observed. There was no association between any polymorphism and major depressive disorder. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  17. Stable isotope labeling, in vivo, of D- and L-tryptophan pools in lemna gibba and the low incorporation of label into indole-3-acetic acid

    International Nuclear Information System (INIS)

    Baldi, B.G.; Maher, B.R.; Slovin, J.P.; Cohen, J.D.

    1991-01-01

    The authors present evidence that the role of tryptophan and other potential intermediates in the pathways that could lead to indole derivatives needs to be reexamined. Two lines of Lemna gibba were tested for uptake of [ 15 N-indole]-labeled tryptophan isomers and incorporation of that label into free indole-3-acetic acid (IAA). Both lines required levels of L-[ 15 N]tryptophan 2 to 3 orders of magnitude over endogenous levels in order to obtain measurable incorporation of label into IAA. Labeled L-tryptophan was extractable from plant tissue after feeding and showed no measurable isomerization into D-tryptophan. D-[ 15 N]trytophan supplied to Lemna at rates of approximately 400 times excess of endogenous D-tryptophan levels (to yield an isotopic enrichment equal to that which allowed detection of the incorporation of L-tryptophan into IAA), did not result in measurable incorporation of label into free IAA. These results demonstrate that L-tryptophan is a more direct precursor to IAA than the D isomer and suggest (a) that the availability of tryptophan in vivo is not a limiting factor in the biosynthesis of IAA, thus implying that other regulatory mechanisms are in operation and (b) that L-tryptophan also may not be a primary precursor to IAA in plants

  18. Candida glabrata tryptophan-based pigment production via the Ehrlich pathway.

    Science.gov (United States)

    Brunke, Sascha; Seider, Katja; Almeida, Ricardo Sergio; Heyken, Antje; Fleck, Christian Benjamin; Brock, Matthias; Barz, Dagmar; Rupp, Steffen; Hube, Bernhard

    2010-04-01

    Pigments contribute to the pathogenicity of many fungi, mainly by protecting fungal cells from host defence activities. Here, we have dissected the biosynthetic pathway of a tryptophan-derived pigment of the human pathogen Candida glabrata, identified key genes involved in pigment production and have begun to elucidate the possible biological function of the pigment. Using transcriptional analyses and a transposon insertion library, we have identified genes associated with pigment production. Targeted deletion mutants revealed that the pigment is a by-product of the Ehrlich pathway of tryptophan degradation: a mutant lacking a tryptophan-upregulated aromatic aminotransferase (Aro8) displayed significantly reduced pigmentation and a recombinantly expressed version of this protein was sufficient for pigment production in vitro. Pigment production is tightly regulated as the synthesis is affected by the presence of alternative nitrogen sources, carbon sources, cyclic AMP and oxygen. Growth of C. glabrata on pigment inducing medium leads to an increased resistance to hydrogen peroxide, an effect which was not observed with a mutant defective in pigmentation. Furthermore, pigmented yeast cells had a higher survival rate when exposed to human neutrophils and caused increased damage in a monolayer model of human epithelia, indicating a possible role of pigmentation during interactions with host cells.

  19. The Potential Role of Cannabinoids in Modulating Serotonergic Signaling by Their Influence on Tryptophan Metabolism

    Directory of Open Access Journals (Sweden)

    Dietmar Fuchs

    2010-08-01

    Full Text Available Phytocannabinoids present in Cannabis plants are well known to exert potent anti-inflammatory and immunomodulatory effects. Previously, we have demonstrated that the psychoactive D9-tetrahydrocannabinol (THC and the non-psychotropic cannabidiol (CBD modulate mitogen-induced Th1-type immune responses in peripheral blood mononuclear cells (PBMC. The suppressive effect of both cannabinoids on mitogen-induced tryptophan degradation mediated by indoleamine-2,3-dioxygenase (IDO, suggests an additional mechanism by which antidepressive effects of cannabinoids might be linked to the serotonergic system. Here, we will review the role of tryptophan metabolism in the course of cell mediated immune responses and the relevance of cannabinoids in serotonergic signaling. We conclude that in particular the non-psychotropic CBD might be useful for the treatment of mood disorders in patients with inflammatory diseases, since this cannabinoid seems to be safe and its effects on activation-induced tryptophan degradation by CBD were more potent as compared to THC.

  20. Application of Tryptophan Fluorescence Bandwidth-Maximum Plot in Analysis of Monoclonal Antibody Structure.

    Science.gov (United States)

    Huang, Cheng-Yen; Hsieh, Ming-Ching; Zhou, Qinwei

    2017-04-01

    Monoclonal antibodies have become the fastest growing protein therapeutics in recent years. The stability and heterogeneity pertaining to its physical and chemical structures remain a big challenge. Tryptophan fluorescence has been proven to be a versatile tool to monitor protein tertiary structure. By modeling the tryptophan fluorescence emission envelope with log-normal distribution curves, the quantitative measure can be exercised for the routine characterization of monoclonal antibody overall tertiary structure. Furthermore, the log-normal deconvolution results can be presented as a two-dimensional plot with tryptophan emission bandwidth vs. emission maximum to enhance the resolution when comparing samples or as a function of applied perturbations. We demonstrate this by studying four different monoclonal antibodies, which show the distinction on emission bandwidth-maximum plot despite their similarity in overall amino acid sequences and tertiary structures. This strategy is also used to demonstrate the tertiary structure comparability between different lots manufactured for one of the monoclonal antibodies (mAb2). In addition, in the unfolding transition studies of mAb2 as a function of guanidine hydrochloride concentration, the evolution of the tertiary structure can be clearly traced in the emission bandwidth-maximum plot.

  1. Caspase recruitment domain 9, microbiota, and tryptophan metabolism: dangerous liaisons in inflammatory bowel diseases.

    Science.gov (United States)

    Lamas, Bruno; Richard, Mathias L; Sokol, Harry

    2017-07-01

    Inflammatory bowel diseases (IBDs) develop as a result of a combination of genetic predisposition, dysbiosis of the gut microbiota, and environmental influences. Here, we describe an example of how caspase recruitment domain 9 (CARD9), one of the numerous IBD susceptibility genes, participate to colitis susceptibility by shaping gut microbiota to produce tryptophan metabolites. Recent study showed that CARD9 mice are more susceptible to colitis as a result of impaired interleukin 22 signaling pathway. Furthermore, aryl hydrocarbon receptor (AhR) ligands from tryptophan metabolism by the gut microbiota participate to intestinal homeostasis by inducing production of interleukin 22 by intestinal immune cells. These data suggest an interaction between CARD9 and the ability of gut microbiota to produce AhR ligands. The microbiota from CARD9 mice fails to metabolize tryptophan leading to defective AhR activation which contributes to the susceptibility of mice to colitis by decreased interleukin 22 production. These effects were abrogated in the presence of AhR agonist. Reduced production of AhR ligands is also observed in the microbiota from individuals with IBD, particularly in those with CARD9 risk alleles associated with IBD. Correcting impaired microbiota functions, such as ability to produce AhR ligands, is an attractive strategy in IBD.

  2. Tryptophan derivatives regulate the transcription of Oct4 in stem-like cancer cells.

    Science.gov (United States)

    Cheng, Jie; Li, Wenxin; Kang, Bo; Zhou, Yanwen; Song, Jiasheng; Dan, Songsong; Yang, Ying; Zhang, Xiaoqian; Li, Jingchao; Yin, Shengyong; Cao, Hongcui; Yao, Hangping; Zhu, Chenggang; Yi, Wen; Zhao, Qingwei; Xu, Xiaowei; Zheng, Min; Zheng, Shusen; Li, Lanjuan; Shen, Binghui; Wang, Ying-Jie

    2015-06-10

    The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to environmental toxicants, is increasingly recognized as a key player in embryogenesis and tumorigenesis. Here we show that a variety of tryptophan derivatives that act as endogenous AhR ligands can affect the transcription level of the master pluripotency factor Oct4. Among them, ITE enhances the binding of the AhR to the promoter of Oct4 and suppresses its transcription. Reduction of endogenous ITE levels in cancer cells by tryptophan deprivation or hypoxia leads to Oct4 elevation, which can be reverted by administration with synthetic ITE. Consequently, synthetic ITE induces the differentiation of stem-like cancer cells and reduces their tumorigenic potential in both subcutaneous and orthotopic xenograft tumour models. Thus, our results reveal a role of tryptophan derivatives and the AhR signalling pathway in regulating cancer cell stemness and open a new therapeutic avenue to target stem-like cancer cells.

  3. Effects of tryptophan depletion on selective serotonin reuptake inhibitor-remitted patients with obsessive compulsive disorder.

    Science.gov (United States)

    Hood, Sean D; Broyd, Annabel; Robinson, Hayley; Lee, Jessica; Hudaib, Abdul-Rahman; Hince, Dana A

    2017-12-01

    Serotonergic antidepressants are first-line medication therapies for obsessive-compulsive disorder, however it is not known if synaptic serotonin availability is important for selective serotonin reuptake inhibitor efficacy. The present study tested the hypothesis that temporary reduction in central serotonin transmission, through acute tryptophan depletion, would result in an increase in anxiety in selective serotonin reuptake inhibitor-remitted obsessive-compulsive disorder patients. Eight patients (four males) with obsessive-compulsive disorder who showed sustained clinical improvement with selective serotonin reuptake inhibitor treatment underwent acute tryptophan depletion in a randomized, double-blind, placebo-controlled, within-subjects design, over two days one week apart. Five hours after consumption of the depleting/sham drink the participants performed a personalized obsessive-compulsive disorder symptom exposure task. Psychological responses were measured using the Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and Visual Analogue Scales. Free plasma tryptophan to large neutral amino acid ratio decreased by 93% on the depletion day and decreased by 1% on the sham day, as anticipated. Psychological rating scores as measured by Visual Analogue Scale showed a significant decrease in perceived control and increase in interfering thoughts at the time of provocation on the depletion day but not on the sham day. A measure of convergent validity, namely Visual Analogue Scale Similar to past, was significantly higher at the time of provocation on both the depletion and sham days. Both the depletion and time of provocation scores for Visual Analogue Scale Anxiety, Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and blood pressure were not significant. Acute tryptophan depletion caused a significant decrease in perceived control and increase in interfering thoughts at the time of provocation. Acute tryptophan

  4. Tryptophan decarboxylase plays an important role in ajmalicine biosynthesis in Rauvolfia verticillata.

    Science.gov (United States)

    Liu, Wanhong; Chen, Rong; Chen, Min; Zhang, Haoxing; Peng, Meifang; Yang, Chunxian; Ming, Xingjia; Lan, Xiaozhong; Liao, Zhihua

    2012-07-01

    Tryptophan decarboxylase (TDC) converts tryptophan into tryptamine that is the indole moiety of ajmalicine. The full-length cDNA of Rauvolfia verticillata (RvTDC) was 1,772 bps that contained a 1,500-bp ORF encoding a 499-amino-acid polypeptide. Recombinant 55.5 kDa RvTDC converted tryptophan into tryptamine. The K (m) of RvTDC for tryptophan was 2.89 mM, higher than those reported in other TIAs-producing plants. It demonstrated that RvTDC had lower affinity to tryptophan than other plant TDCs. The K (m) of RvTDC was also much higher than that of strictosidine synthase and strictosidine glucosidase in Rauvolfia. This suggested that TDC might be the committed-step enzyme involved in ajmalicine biosynthesis in R. verticillata. The expression of RvTDC was slightly upregulated by MeJA; the five MEP pathway genes and SGD showed no positive response to MeJA; and STR was sharply downregulated by MeJA. MeJA-treated hairy roots produced higher level of ajmalicine (0.270 mg g(-1) DW) than the EtOH control (0.183 mg g(-1) DW). Highest RvTDC expression level was detected in hairy root, about respectively 11, 19, 65, and 109-fold higher than in bark, young leaf, old leaf, and root. Highest ajmalicine content was also found in hairy root (0.249 mg g(-1) DW) followed by in bark (0.161 mg g(-1) DW) and young leaf (0.130 mg g(-1) DW), and least in root (0.014 mg g(-1) DW). Generally, the expression level of RvTDC was positively consistent with the accumulation of ajmalicine. Therefore, it could be deduced that TDC might be the key enzyme involved in ajmalicine biosynthesis in Rauvolfia.

  5. Profiling of tryptophan-related plasma indoles in patients with carcinoid tumors by automated, on-line, solid-phase extraction and HPLC with fluorescence detection.

    Science.gov (United States)

    Kema, I P; Meijer, W G; Meiborg, G; Ooms, B; Willemse, P H; de Vries, E G

    2001-10-01

    Profiling of the plasma indoles tryptophan, 5-hydroxytryptophan (5-HTP), serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) is useful in the diagnosis and follow-up of patients with carcinoid tumors. We describe an automated method for the profiling of these indoles in protein-containing matrices as well as the plasma indole concentrations in healthy controls and patients with carcinoid tumors. Plasma, cerebrospinal fluid, and tissue homogenates were prepurified by automated on-line solid-phase extraction (SPE) in Hysphere Resin SH SPE cartridges containing strong hydrophobic polystyrene resin. Analytes were eluted from the SPE cartridge by column switching. Subsequent separation and detection were performed by reversed-phase HPLC combined with fluorometric detection in a total cycle time of 20 min. We obtained samples from 14 healthy controls and 17 patients with metastasized midgut carcinoid tumors for plasma indole analysis. In the patient group, urinary excretion of 5-HIAA and serotonin was compared with concentrations of plasma indoles. Within- and between-series CVs for indoles in platelet-rich plasma were 0.6-6.2% and 3.7-12%, respectively. Results for platelet-rich plasma serotonin compared favorably with those obtained by single-component analysis. Plasma 5-HIAA, but not 5-HTP was detectable in 8 of 17 patients with carcinoid tumors. In the patient group, platelet-rich plasma total tryptophan correlated negatively with platelet-rich plasma serotonin (P = 0.021; r = -0.56), urinary 5-HIAA (P = 0.003; r = -0.68), and urinary serotonin (P manual, single-component analyses.

  6. Revisiting the tryptophan-serotonin deficiency and the inflammatory hypotheses of major depression in a biopsychosocial approach

    Directory of Open Access Journals (Sweden)

    Andreas Baranyi

    2017-11-01

    Full Text Available Background The aim of this cross-sectional study was to identify important biopsychosocial correlates of major depression. Biological mechanisms, including the inflammatory and the tryptophan-serotonin deficiency hypotheses of major depression, were investigated alongside health-related quality of life, life satisfaction, and social support. Methods The concentrations of plasma tryptophan, plasma kynurenine, plasma kynurenic acid, serum quinolinic acid, and the tryptophan breakdown to kynurenine were determined alongside health-related quality of life (Medical Outcome Study Form, SF-36, life satisfaction (Life Satisfaction Questionnaire, FLZ, and social support (Social Support Survey, SSS in 71 depressive patients at the time of their in-patient admittance and 48 healthy controls. Results Corresponding with the inflammatory hypothesis of major depression, our study results suggest a tryptophan breakdown to kynurenine in patients with major depression, and depressive patients had a lower concentration of neuroprotective kynurenic acid in comparison to the healthy controls (Mann–Whitney-U: 1315.0; p = 0.046. Contradicting the inflammatory theory, the concentrations of kynurenine (t: −0.945; df = 116; p = 0.347 and quinolinic acid (Mann-Whitney-U: 1376.5; p = 0.076 in depressive patients were not significantly different between depressed and healthy controls. Our findings tend to support the tryptophan-serotonin deficiency hypothesis of major depression, as the deficiency of the serotonin precursor tryptophan in depressive patients (t: −3.931; df = 116; p < 0.001 suggests dysfunction of serotonin neurotransmission. A two-step hierarchical linear regression model showed that low tryptophan concentrations, low social support (SSS, occupational requirements (FLZ, personality traits (FLZ, impaired physical role (SF-36, and impaired vitality (SF-36 predict higher Beck Depression Inventory (BDI-II scores. Discussion Our study results

  7. Regular moderate or intense exercise prevents depression-like behavior without change of hippocampal tryptophan content in chronically tryptophan-deficient and stressed mice.

    Directory of Open Access Journals (Sweden)

    Hosung Lee

    Full Text Available Regular exercise has an antidepressant effect in human subjects. Studies using animals have suggested that the antidepressant effect of exercise is attributable to an increase of brain 5-hydroxytryptamine (5-HT; however, the precise mechanism underlying the antidepressant action via exercise is unclear. In contrast, the effect of 5-HT on antidepressant activity has not been clarified, in part because the therapeutic response to antidepressant drugs has a time lag in spite of the rapid increase of brain 5-HT upon administration of these drugs. This study was designed to investigate the contribution of brain 5-HT to the antidepressant effect of exercise. Mice were fed a tryptophan-deficient diet and stressed using chronic unpredictable stress (CUS for 4 weeks with or without the performance of either moderate or intense exercise on a treadmill 3 days per week. The findings demonstrated that the onset of depression-like behavior is attributable not to chronic reduction of 5-HT but to chronic stress. Regular exercise, whether moderate or intense, prevents depression-like behavior with an improvement of adult hippocampal cell proliferation and survival and without the recovery of 5-HT. Concomitantly, the mice that exercised showed increased hippocampal noradrenaline. Regular exercise prevents the impairment of not long-term memory but short-term memory in a 5-HT-reduced state. Together, these findings suggest that: (1 chronic reduction of brain 5-HT may not contribute to the onset of depression-like behavior; (2 regular exercise, whether moderate or intense, prevents the onset of chronic stress-induced depression-like behavior independent of brain 5-HT and dependent on brain adrenaline; and (3 regular exercise prevents chronic tryptophan reduction-induced impairment of not long-term but short-term memory.

  8. [Development of residual voltage testing equipment].

    Science.gov (United States)

    Zeng, Xiaohui; Wu, Mingjun; Cao, Li; He, Jinyi; Deng, Zhensheng

    2014-07-01

    For the existing measurement methods of residual voltage which can't turn the power off at peak voltage exactly and simultaneously display waveforms, a new residual voltage detection method is put forward in this paper. First, the zero point of the power supply is detected with zero cross detection circuit and is inputted to a single-chip microcomputer in the form of pulse signal. Secend, when the zero point delays to the peak voltage, the single-chip microcomputer sends control signal to power off the relay. At last, the waveform of the residual voltage is displayed on a principal computer or oscilloscope. The experimental results show that the device designed in this paper can turn the power off at peak voltage and is able to accurately display the voltage waveform immediately after power off and the standard deviation of the residual voltage is less than 0.2 V at exactly one second and later.

  9. Highly Conserved Arg Residue of ERFNIN Motif of Pro-Domain is Important for pH-Induced Zymogen Activation Process in Cysteine Cathepsins K and L.

    Science.gov (United States)

    Aich, Pulakesh; Biswas, Sampa

    2018-06-01

    Pro-domain of a cysteine cathepsin contains a highly conserved Ex 2 Rx 2 Fx 2 Nx 3 Ix 3 N (ERFNIN) motif. The zymogen structure of cathepsins revealed that the Arg(R) residue of the motif is a central residue of a salt-bridge/H-bond network, stabilizing the scaffold of the pro-domain. Importance of the arginine is also demonstrated in studies where a single mutation (Arg → Trp) in human lysosomal cathepsin K (hCTSK) is linked to a bone-related genetic disorder "Pycnodysostosis". In the present study, we have characterized in vitro Arg → Trp mutant of hCTSK and the same mutant of hCTSL. The R → W mutant of hCTSK revealed that this mutation leads to an unstable zymogen that is spontaneously activated and auto-proteolytically degraded rapidly. In contrast, the same mutant of hCTSL is sufficiently stable and has proteolytic activity almost like its wild-type counterpart; however it shows an altered zymogen activation condition in terms of pH, temperature and time. Far and near UV circular dichroism and intrinsic tryptophan fluorescence experiments have revealed that the mutation has minimal effect on structure of the protease hCTSL. Molecular modeling studies shows that the mutated Trp31 in hCTSL forms an aromatic cluster with Tyr23 and Trp30 leading to a local stabilization of pro-domain and supplements the loss of salt-bridge interaction mediated by Arg31 in wild-type. In hCTSK-R31W mutant, due to presence of a non-aromatic Ser30 residue such interaction is not possible and may be responsible for local instability. These differences may cause detrimental effects of R31W mutation on the regulation of hCTSK auto-activation process compared to altered activation process in hCTSL.

  10. Psychosocial stress and inflammation driving tryptophan breakdown in children and adolescents: A cross-sectional analysis of two cohorts.

    Science.gov (United States)

    Michels, Nathalie; Clarke, Gerard; Olavarria-Ramirez, Loreto; Gómez-Martínez, Sonia; Díaz, Ligia Esperanza; Marcos, Ascensión; Widhalm, Kurt; Carvalho, Livia A

    2018-05-15

    Tryptophan breakdown is an important mechanism in several diseases e.g. inflammation and stress-induced inflammation have been associated with the development of depression via enhanced tryptophan breakdown. Depression is a major public health problem which commonly starts during adolescence, thus identifying underlying mechanisms during early life is crucial in prevention. The aim of this work was to verify whether independent and interacting associations of psychosocial stress and inflammation on tryptophan breakdown already exist in children and adolescents as a vulnerable age group. Two cross-sectional population-based samples of children/adolescents (8-18 y) were available: 315 from the European HELENA study and 164 from the Belgian ChiBS study. In fasting serum samples, tryptophan, kynurenine, kynurenic acid, C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (IFN)-ɣ, soluble vascular adhesion molecule 1 (sVCAM1) and soluble intercellular adhesion molecule 1 (sICAM1) were measured. Psychological stress was measured by stress reports (subjective) and cortisol (objective - awakening salivary cortisol or hair cortisol). Linear regressions with stress or inflammation as predictor were adjusted for age, sex, body mass index, puberty, socio-economic status and country. In both cohorts, inflammation as measured by higher levels of CRP, sVCAM1 and sICAM1 was associated with kynurenine/tryptophan ratio and thus enhanced tryptophan breakdown (beta: 0.145-0.429). Psychological stress was only associated with tryptophan breakdown in the presence of higher inflammatory levels (TNF-α in both populations). Inflammatory levels were replicable key in enhancing tryptophan breakdown along the kynurenine pathway, even at young age and in a non-clinical sample. The stress-inflammation interaction indicated that only the stress exposures inducing higher inflammatory levels (or in an already existing inflammatory status) were associated

  11. Effect of surface roughness and surface modification of indium tin oxide electrode on its potential response to tryptophan

    International Nuclear Information System (INIS)

    Khan, Md. Zaved Hossain; Nakanishi, Takuya; Kuroiwa, Shigeki; Hoshi, Yoichi; Osaka, Tetsuya

    2011-01-01

    Highlights: → We examine factors affecting potential response of ITO electrode to tryptophan. → Surface roughness of ITO electrode affects the stability of its rest potential. → Surface modification is effective for ITO electrode with a certain roughness. → Optimum values of work function exist for potential response of ITO to tryptophan. - Abstract: The effect of surface modification of indium tin oxide (ITO) electrode on its potential response to tryptophan was investigated for ITO substrates with different surface roughness. It was found that a small difference in surface roughness, between ∼1 and ∼2 nm of R a evaluated by atomic force microscopy, affects the rest potential of ITO electrode in the electrolyte. A slight difference in In:Sn ratio at the near surface of the ITO substrates, measured by angle-resolved X-ray photoelectron spectrometry and Auger electron spectroscopy is remarkable, and considered to relate with surface roughness. Interestingly, successive modification of the ITO surface with aminopropylsilane and disuccinimidyl suberate, of which essentiality to the potential response to indole compounds we previously reported, improved the stability of the rest potential and enabled the electrodes to respond to tryptophan in case of specimens with R a values ranging between ∼2 and ∼3 nm but not for those with R a of ∼1 nm. It was suggested that there are optimum values of effective work function of ITO for specific potential response to tryptophan, which can be obtained by the successive modification of ITO surface.

  12. Meal Pattern of Male Rats Maintained on Amino Acid Supplemented Diets: The Effect of Tryptophan, Lysine, Arginine, Proline and Threonine

    Directory of Open Access Journals (Sweden)

    Raghad Ayaso

    2014-07-01

    Full Text Available The macronutrient composition of the diet has been shown to affect food intake, with proteins having distinct effects. The present study investigated the effect of diet supplementation with individual amino acids (tryptophan, lysine, arginine, proline and threonine on meal pattern among male rats. Meal pattern and body weight were monitored for two weeks. Proline and threonine had minimal effects on meal pattern, while the most pronounced changes were observed in the tryptophan group. Both tryptophan and lysine decreased overall food intake, which was translated into a reduction in body weight. The reduced food intake of the tryptophan group was associated with an increase in meal size, intermeal intervals (IMI and meal time and a decrease in meal number. The decrease in the food intake of the lysine group was associated with a reduction in both IMI and meal number, and this was accompanied by an increase in meal time. Arginine increased meal number, while decreasing IMI. Proline and threonine had a minimal effect on meal pattern. Lysine seems to increase satiety, and arginine seems to decrease it, while tryptophan seems to increase satiety and decrease satiation. Accordingly, changes in meal patterns are associated with the type of amino acid added to the diet.

  13. Correlation between breakfast tryptophan content and morning-evening in Japanese infants and students aged 0-15 yrs.

    Science.gov (United States)

    Harada, Tetsuo; Hirotani, Masaaki; Maeda, Mari; Nomura, Hiromi; Takeuchi, Hitomi

    2007-03-01

    Tryptophan can be metabolized via 5-hydroxytryptamine=serotonin to melatonin by a series of 4 enzymes in pineal body. Lack of serotonin in body fluid in the brain during daytime can lead to several psychiatric disorders, while shortage of plasma-melatonin at night can be related to sleep disorders. The Morning-Evening (M-E) questionnaire and the original questionnaire including questions on sleep habits, mental symptoms, and contents of meals were administered to 1055 infants aged 0-6 yrs, 751 students attending an elementary school, and 473 students attending junior high school in Kochi City (33 degrees N). The index of tryptophan taken at breakfast (Trp-Index) was calculated as tryptophan amount per one meal based on the tryptophan included in each 100 g of the foods and a standard amount of food per one meal. A significant positive-correlation between M-E scores and Trp-Index was not shown by relatively older students, aged 9-15 yrs (Pearson's test, r=0.044-0.123, p=0.071-0.505), whereas a significant positive correlation was shown by infants and young elementary school students aged 0-8 yrs (r=0.180, 0.258, phigh quality of sleep, and indirectly good mental health, presumably, through the metabolism of tryptophan to serotonin in daytime and further to melatonin at night.

  14. Effects of Tranilast on the Urinary Excretion of Kynurenic and Quinolinic Acid under Conditions of L Tryptophan Loading

    Directory of Open Access Journals (Sweden)

    Rowland R. Noakes

    2013-01-01

    Full Text Available The pathogenesis of morphea and other cutaneous sclerosing disorders remain poorly understood. Although they are considered to be autoimmune disorders, abnormal tryptophan metabolism may be involved. Current therapy is directed to supressing the autoimmune response. Demonstration of a therapeutic response to manipulation of the kynurenine pathway would both support a role for abnormal tryptophan metabolism and offer additional targets for therapy. Tranilast is a 3-hydroxyanthranilic acid derivative known to target the kynurenine pathway. The aim of this study was to see if tranilast lowered the urinary excretion of the kynurenine metabolites kynurenic and quinolinic acid under condition of L tryptophan loading in a volunteer. Mean baseline value for kynurenic acid and quinolinic acid were 1.1 and 2.1 mmol/mol creatinine, respectively. This rose to 5.6 and 3.8 mmol/mol creatinine respectively under conditions of L tryptophan loading 2 grams daily. Adding 1 g of tranilast daily lowered the values to 2.0 and 2.9 mmol/mol creatinine, respectively. These data suggest that tranilast acts as a competitive inhibitor of either indoleamine 2, 3-dioxygenase (IDO, tryptophan 2, 3 di-oxygenase (TDO or both. As it involved only 1 subject, the results may not be representative of the larger population and must be considered preliminary.

  15. Alpha-tryptophan synthase of Isatis tinctoria: gene cloning and expression.

    Science.gov (United States)

    Salvini, M; Boccardi, T M; Sani, E; Bernardi, R; Tozzi, S; Pugliesi, C; Durante, M

    2008-07-01

    Indole producing reaction is a crux in the regulation of metabolite flow through the pathways and the coordination of primary and secondary product biosynthesis in plants. Indole is yielded transiently from indole-3-glycerol phosphate and immediately condensed with serine to give tryptophan, by the enzyme tryptophan synthase (TS). There is evidence that plant TS, like the bacterial complex, functions as an alpha beta heteromer. In few species, e.g. maize, are known enzymes, related with the TS alpha-subunit (TSA), able to catalyse reaction producing indole, which is free to enter the secondary metabolite pathways. In this contest, we searched for TSA and TSA related genes in Isatis tinctoria, a species producing the natural blue dye indigo. The It-TSA cDNA and the full-length exons/introns genomic region were isolated. The phylogenetic analysis indicates that It-TSA is more closely related to Arabidopsis thaliana At-T14E10.210 TSA (95.7% identity at the amino acid level) with respect to A. thaliana At-T10P11.11 TSA1-like (63%), Zea mays indole-3-glycerol phosphate lyase (54%), Z. mays TSA (53%), and Z. mays indole synthase (50%). The It-TSA cDNA was also able to complement an Escherichia coli trpA mutant. To examine the involvement of It-TSA in the biosynthesis of secondary metabolism compounds, It-TSA expression was tested in seedling grown under different light conditions. Semi-quantitative RT-PCR showed an increase in the steady-state level of It-TSA mRNA, paralleled by an increase of indigo and its precursor isatan B. Our results appear to indicate an involvement for It-TSA in indigo precursor synthesis and/or tryptophan biosynthesis.

  16. Neopterin, kynurenine and tryptophan as new biomarkers for early detection of rectal anastomotic leakage.

    Science.gov (United States)

    Dusek, Tomas; Orhalmi, Julius; Sotona, Otakar; Krcmova, Lenka Kujovska; Javorska, Lenka; Dolejs, Josef; Paral, Jiri

    2018-03-01

    At present, there are no strong predictors, nor a useful scoring system, that clearly identifies patients at risk for anastomotic leakage. This study aimed to investigate a new method that assesses this risk by monitoring levels of neopterin, tryptophan, and kynurenine, in bodily fluids. This prospective study included patients who underwent elective rectal resection for carcinoma. The basic condition for inclusion was rectal anastomosis using the double-stapling technique. Preoperative levels of neopterin, tryptophan, kynurenine, and their ratios, were assessed with blood and urine samples. These levels were then monitored for 6 postoperative days in venous blood, urine, and abdominal drainage fluid. A total of 42 patients were enrolled in the study. Thirty-six patients underwent a laparoscopic resection and 6 patients had an open procedure. No differences were found among neopterin, tryptophan, and kynurenine serum levels. However, the groups were observed to have significant differences in the urinary neopterin/creatinine ratio: the preoperative neopterin/creatinine ratio was 139.5 μmol/mol in the group with leakage, vs 114.8 μmol/mol in the group without complications, p = 0.037. The same results were observed during the postoperative period, p = 0.012. Additionally, the group with complications had a higher mean value of neopterin in drainage fluid, p = 0.048. Our study demonstrated that high preoperative levels of urinary neopterin could be interpreted as a risk for anastomotic leakage. Moreover, pathological levels of neopterin in urine and abdominal drainage fluid could be useful for early identification of anastomotic leakage during the postoperative period prior to its clinical development.

  17. The Role of Amino Acid Permeases and Tryptophan Biosynthesis in Cryptococcus neoformans Survival.

    Directory of Open Access Journals (Sweden)

    João Daniel Santos Fernandes

    Full Text Available Metabolic diversity is an important factor during microbial adaptation to different environments. Among metabolic processes, amino acid biosynthesis has been demonstrated to be relevant for survival for many microbial pathogens, whereas the association between pathogenesis and amino acid uptake and recycling are less well-established. Cryptococcus neoformans is an opportunistic fungal pathogen with many habitats. As a result, it faces frequent metabolic shifts and challenges during its life cycle. Here we studied the C. neoformans tryptophan biosynthetic pathway and found that the pathway is essential. RNAi indicated that interruptions in the biosynthetic pathway render strains inviable. However, auxotroph complementation can be partially achieved by tryptophan uptake when a non preferred nitrogen source and lower growth temperature are applied, suggesting that amino acid permeases may be the target of nitrogen catabolism repression (NCR. We used bioinformatics to search for amino acid permeases in the C. neoformans and found eight potential global permeases (AAP1 to AAP8. The transcriptional profile of them revealed that they are subjected to regulatory mechanisms which are known to respond to nutritional status in other fungi, such as (i quality of nitrogen (Nitrogen Catabolism Repression, NCR and carbon sources (Carbon Catabolism Repression, CCR, (ii amino acid availability in the extracellular environment (SPS-sensing and (iii nutritional deprivation (Global Amino Acid Control, GAAC. This study shows that C. neoformans has fewer amino acid permeases than other model yeasts, and that these proteins may be subjected to complex regulatory mechanisms. Our data suggest that the C. neoformans tryptophan biosynthetic pathway is an excellent pharmacological target. Furthermore, inhibitors of this pathway cause Cryptococcus growth arrest in vitro.

  18. Schiff bases derived from L-Tyrosine L-Tryptophan and their Cu(II) chelates as effective means for preventive-treatment of radiation injuries

    International Nuclear Information System (INIS)

    Malakyan, M.H.; Bajinyan, S.A.; Matosyan, V.H.; Tonoyan, V.J.; Babayan, K.N.; Boyajyan, A.S.; Yeghiazaryan, D.E.; Vardevanyan, L.A.; Sorenson, J.R.J.

    2008-01-01

    Full text: Study on essential metallo element chelates as radioprotectors presents a promising direction in a search for and development of novel anti-radiation agents and offers a new approach to overcome the pathological effects of ionizing radiation. The key idea elucidating the radioprotective effects of metallo element-containing chelates of amino acid derivatives is their role in stimulation of de novo synthesis of metallo element-dependent enzymes required for recovery of hemopoietic activity and immuno competency lost as a consequence of radiation damage. Aimed to develop novel anti-radiation remedies of less toxicity and high efficacy, Schiff bases derived from L-Tyrosine and L-Tryptophan and their Cu(II) chelates were synthesized. In experiments in vitro and in vivo biological and pharmacological properties of the mentioned Schiff Bases and their copper complexes are under study. According to the results obtained, L-Tyrosinate and L-Tryptophanate Schiff bases are low toxic compounds with a weak antioxidant activity and exert radioprotective effects in case of animal X-ray irradiation at a dose level equal or less than LD 50/30 . Unlike Schiff Bases, their appropriate Cu(II) chelates possess high anti radical/antioxidant activity and manifest expressed radio-protective action at LD 100/30 dose of ionizing radiation. Anti-radiation effects of amino acid Schiff bases and their metallo chelates are manifested in case of both subcutaneous and oral single administration to the animal organism at 10, 20, or 40 mg/kg 1, 3, 6, or 24 hours prior to radiation exposure. Conclusions are drawn basing on determinations of survival and average life-span indices of irradiated animals, as well as on studies for their hematological, biochemical, immunological, biophysical indices. It is revealed that on the background of preliminary administration of the compounds studied to the animal organism the characteristics of DNA are significantly improved, the immune status

  19. Cysteine and tryptophan anomalies found when scanning all the binding sites in the Protein Data Bank.

    Science.gov (United States)

    Iván, Gábor; Szabadka, Zoltán; Grolmusz, Vince

    2010-01-01

    The Protein Data Bank (PDB) is one of the richest sources of structural biological information in the World. It started to exist as the computer-readable depository of crystallographic data complementing printed papers. The proper interpretation of the content of the individual files in the PDB still needs the detailed information found in the citing publication. An advanced graph theoretical method is presented here for automatically repairing, re-organising and re-structuring PDB data yielding the identification of all the protein-ligand complexes and all the binding sites in the PDB. As an application, we identified strong cysteine and tryptophan irregularities in the data.

  20. Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

    Directory of Open Access Journals (Sweden)

    Gergely L. Tolnai

    2016-04-01

    Full Text Available The selective functionalization of peptides containing only natural amino acids is important for the modification of biomolecules. In particular, the installation of an alkyne as a useful handle for bioconjugation is highly attractive, but the use of a carbon linker is usually required. Herein, we report the gold-catalyzed direct alkynylation of tryptophan in peptides using the hypervalent iodine reagent TIPS-EBX (1-[(triisopropylsilylethynyl]-1,2-benziodoxol-3(1H-one. The reaction proceeded in 50–78% yield under mild conditions and could be applied to peptides containing other nucleophilic and aromatic amino acids, such as serine, phenylalanine or tyrosine.

  1. Converging evidence for central 5-HT effects in acute tryptophan depletion

    DEFF Research Database (Denmark)

    Crockett, Molly; Clark, Luke; Roiser, Jonathan

    2012-01-01

    the validity of ATD.2 Although we agree that ATD's effects on 5-HT activity at the molecular level need further clarification, van Donkelaar et al.2 goes too far in challenging whether ATD exerts its effects through serotonergic mechanisms. There is strong evidence that ATD reduces brain 5-HT and disrupts......Acute tryptophan depletion (ATD), a dietary technique for manipulating brain serotonin (5-HT) function, has advanced our understanding of 5-HT mechanisms in the etiology and treatment of depression and other affective disorders.1 A recent review article in Molecular Psychiatry questioned...

  2. Model of the complex of Parathyroid hormone-2 receptor and Tuberoinfundibular peptide of 39 residues

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    Persson Bengt

    2010-10-01

    Full Text Available Abstract Background We aim to propose interactions between the parathyroid hormone-2 receptor (PTH2R and its ligand the tuberoinfundibular peptide of 39 residues (TIP39 by constructing a homology model of their complex. The two related peptides parathyroid hormone (PTH and parathyroid hormone related protein (PTHrP are compared with the complex to examine their interactions. Findings In the model, the hydrophobic N-terminus of TIP39 is buried in a hydrophobic part of the central cavity between helices 3 and 7. Comparison of the peptide sequences indicates that the main discriminator between the agonistic peptides TIP39 and PTH and the inactive PTHrP is a tryptophan-phenylalanine replacement. The model indicates that the smaller phenylalanine in PTHrP does not completely occupy the binding site of the larger tryptophan residue in the other peptides. As only TIP39 causes internalisation of the receptor and the primary difference being an aspartic acid in position 7 of TIP39 that interacts with histidine 396 in the receptor, versus isoleucine/histidine residues in the related hormones, this might be a trigger interaction for the events that cause internalisation. Conclusions A model is constructed for the complex and a trigger interaction for full agonistic activation between aspartic acid 7 of TIP39 and histidine 396 in the receptor is proposed.

  3. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  4. Spectrofluorometric and Molecular Modeling Studies on Binding of Nitrite Ion with Bovine Hemoglobin: Effect of Nitrite Ion on Amino Acid Residues

    Science.gov (United States)

    Madrakian, T.; Bagheri, H.; Afkhami, A.

    2015-05-01

    The interaction between nitrite ion and bovine hemoglobin was investigated by a spectrofluorometric technique. The experimental results indicated that the interaction causes a static quenching of the fluorescence of bovine hemoglobin, that the binding reaction is spontaneous, and that H-bonding interactions play a major role in binding of this ion to bovine hemoglobin. The formation constant for this interaction was calculated. Based on Förster's theory of nonradiative energy transfer, the binding distance between this ion and bovine hemoglobin was determined. Furthermore, the interaction of nitrite ion with tyrosine and tryptophan was investigated with synchronous fluorescence. There was no significant shift of the maximum emission wavelength with interactions of the mentioned ion with bovine hemoglobin, which implies that interaction of nitrite ion with bovine hemoglobin does not affect the microenvironment around the tryptophan and tyrosine residues. Furthermore, the effect of nitrite ion on amino acid residues of bovine hemoglobin was studied by a molecular docking technique.

  5. Intrinsic Tryptophan Fluorescence in the Detection and Analysis of Proteins: A Focus on Förster Resonance Energy Transfer Techniques

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    Amar B. T. Ghisaidoobe

    2014-12-01

    Full Text Available F resonance energy transfer (FRET occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (\\(\\uplambda_{\\textsc{ex}}\\sim\\ nm, \\(\\uplambda_{\\textsc{em}}\\sim\\ 350 nm, in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the proteinlocal environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic F resonance energy transfer (iFRET, a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins.

  6. Effects of L-tryptophan, Fructan, and Casein on Reducing Ammonia, Hydrogen Sulfide, and Skatole in Fermented Swine Manure

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    Q. K. Sheng

    2015-08-01

    Full Text Available The effects of daily dietary Bacillus subtilis (Bs, and adding L-tryptophan, fructan, or casein to fecal fermentation broths were investigated as means to reduce the production of noxious gas during manure fermentation caused by ammonia, hydrogen sulfide (H2S, and 3-methylindole (skatole. Eighty swine (50.0±0.5 kg were equally apportioned to an experimental group given Bs in daily feed, or a control group without Bs. After 6 weeks, fresh manure was collected from both groups for fermentation studies using a 3×3 orthogonal array, in which tryptophan, casein, and fructan were added at various concentrations. After fermentation, the ammonia, H2S, L-tryptophan, skatole, and microflora were measured. In both groups, L-tryptophan was the principle additive increasing skatole production, with significant correlation (r = 0.9992. L-tryptophan had no effect on the production of ammonia, H2S, or skatole in animals fed Bs. In both groups, fructan was the principle additive that reduced H2S production (r = 0.9981. Fructan and Bs significantly interacted in H2S production (p = 0.014. Casein was the principle additive affecting the concentration of ammonia, only in the control group. Casein and Bs significantly interacted in ammonia production (p = 0.039. The predominant bacteria were Bacillus spp. CWBI B1434 (26% in the control group, and Streptococcus alactolyticus AF201899 (36% in the experimental group. In summary, daily dietary Bs reduced ammonia production during fecal fermentation. Lessening L-tryptophan and increasing fructan in the fermentation broth reduced skatole and H2S.

  7. Altered tryptophan and alanine transport in fibroblasts from boys with attention-deficit/hyperactivity disorder (ADHD: an in vitro study

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    Vumma Ravi

    2011-09-01

    Full Text Available Abstract Background The catecholaminergic and serotonergic neurotransmitter systems are implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD. The amino acid tyrosine is the precursor for synthesis of the catecholamines dopamine and norepinephrine, while tryptophan is the precursor of serotonin. A disturbed transport of tyrosine, as well as other amino acids, has been found in a number of other psychiatric disorders, such as schizophrenia, bipolar disorder and autism, when using the fibroblast cell model. Hence, the aim of this study was to explore whether children with ADHD may have disturbed amino acid transport. Methods Fibroblast cells were cultured from skin biopsies obtained from 14 boys diagnosed with ADHD and from 13 matching boys without a diagnosis of a developmental disorder. Transport of the amino acids tyrosine, tryptophan and alanine across the cell membrane was measured by the cluster tray method. The kinetic parameters, maximal transport capacity (Vmax and affinity constant (Km were determined. Any difference between the two groups was analyzed by Student's unpaired t-test or the Mann Whitney U test. Results The ADHD group had significantly decreased Vmax (p = 0.039 and Km (increased affinity (p = 0.010 of tryptophan transport in comparison to controls. They also had a significantly higher Vmaxof alanine transport (p = 0.031, but the Km of alanine transport did not differ significantly. There were no significant differences in any of the kinetic parameters regarding tyrosine transport in fibroblasts for the ADHD group. Conclusions Tryptophan uses the same transport systems in both fibroblasts and at the blood brain barrier (BBB. Hence, a decreased transport capacity of tryptophan implies that less tryptophan is being transported across the BBB in the ADHD group. This could lead to deficient serotonin access in the brain that might cause disturbances in both the serotonergic and the catecholaminergic

  8. Influence of the tryptophan-indole-IFNγ axis on human genital Chlamydia trachomatis infection: role of vaginal co-infections.

    Science.gov (United States)

    Aiyar, Ashok; Quayle, Alison J; Buckner, Lyndsey R; Sherchand, Shardulendra P; Chang, Theresa L; Zea, Arnold H; Martin, David H; Belland, Robert J

    2014-01-01

    The natural history of genital Chlamydia trachomatis infections can vary widely; infections can spontaneously resolve but can also last from months to years, potentially progressing to cause significant pathology. The host and bacterial factors underlying this wide variation are not completely understood, but emphasize the bacterium's capacity to evade/adapt to the genital immune response, and/or exploit local environmental conditions to survive this immune response. IFNγ is considered to be a primary host protective cytokine against endocervical C. trachomatis infections. IFNγ acts by inducing the host enzyme indoleamine 2,3-dioxgenase, which catabolizes tryptophan, thereby depriving the bacterium of this essential amino acid. In vitro studies have revealed that tryptophan deprivation causes Chlamydia to enter a viable but non-infectious growth pattern that is termed a persistent growth form, characterized by a unique morphology and gene expression pattern. Provision of tryptophan can reactivate the bacterium to the normal developmental cycle. There is a significant difference in the capacity of ocular and genital C. trachomatis serovars to counter tryptophan deprivation. The latter uniquely encode a functional tryptophan synthase to synthesize tryptophan via indole salvage, should indole be available in the infection microenvironment. In vitro studies have confirmed the capacity of indole to mitigate the effects of IFNγ; it has been suggested that a perturbed vaginal microbiome may provide a source of indole in vivo. Consistent with this hypothesis, the microbiome associated with bacterial vaginosis includes species that encode a tryptophanase to produce indole. In this review, we discuss the natural history of genital chlamydial infections, morphological and molecular changes imposed by IFNγ on Chlamydia, and finally, the microenvironmental conditions associated with vaginal co-infections that can ameliorate the effects of IFNγ on C. trachomatis.

  9. Influence of the tryptophan-indole-IFNγ axis on human genital Chlamydia trachomatis infection: role of vaginal co-infections

    Directory of Open Access Journals (Sweden)

    Ashok eAiyar

    2014-06-01

    Full Text Available The natural history of genital Chlamydia trachomatis infections can vary widely; infections can spontaneously resolve but can also last from months to years, potentially progressing to cause significant pathology. The host and bacterial factors underlying this wide variation are not completely understood, but emphasize the bacterium’s capacity to evade/adapt to the genital immune response, and/or exploit local environmental conditions to survive this immune response. IFNγ is considered to be a primary host protective cytokine against endocervical C. trachomatis infections. IFNγ acts by inducing the host enzyme indoleamine 2,3-dioxygenase, which catabolizes tryptophan, thereby depriving the bacterium of this essential amino acid. In vitro studies have revealed that tryptophan deprivation causes Chlamydia to enter a viable but non-infectious growth pattern that is termed a persistent growth form, characterized by a unique morphology and gene expression pattern. Provision of tryptophan can reactivate the bacterium to the normal developmental cycle. There is a significant difference in the capacity of ocular and genital C. trachomatis serovars to counter tryptophan deprivation. The latter uniquely encode a functional tryptophan synthase to synthesize tryptophan via indole salvage, should indole be available in the infection microenvironment. In vitro studies have confirmed the capacity of indole to mitigate the effects of IFNγ; it has been suggested that a perturbed vaginal microbiome may provide a source of indole in vivo. Consistent with this hypothesis, the microbiome associated with bacterial vaginosis includes species that encode a tryptophanase to produce indole. In this review, we discuss the natural history of genital chlamydial infections, morphological and molecular changes imposed by IFNγ on Chlamydia, and finally, the microenvironmental conditions associated with vaginal co-infections that can ameliorate the effects of IFNγ on C

  10. Tryptophan, thiamine and indole-3-acetic acid exchange between Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense.

    Science.gov (United States)

    Palacios, Oskar A; Gomez-Anduro, Gracia; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    During synthetic mutualistic interactions between the microalga Chlorella sorokiniana and the plant growth-promoting bacterium (PGPB) Azospirillum brasilense, mutual exchange of resources involved in producing and releasing the phytohormone indole-3-acetic acid (IAA) by the bacterium, using tryptophan and thiamine released by the microalga, were measured. Although increased activities of tryptophan synthase in C. sorokiniana and indole pyruvate decarboxylase (IPDC) in A. brasilense were observed, we could not detect tryptophan or IAA in the culture medium when both organisms were co-immobilized. This indicates that no extra tryptophan or IAA is produced, apart from the quantities required to sustain the interaction. Over-expression of the ipdC gene occurs at different incubation times: after 48 h, when A. brasilense was immobilized alone and grown in exudates of C. sorokiniana and at 96 h, when A. brasilense was co-immobilized with the microalga. When A. brasilense was cultured in exudates of C. sorokiniana, increased expression of the ipdC gene, corresponding increase in activity of IPDC encoded by the ipdC gene, and increase in IAA production were measured during the first 48 h of incubation. IAA production and release by A. brasilense was found only when tryptophan and thiamine were present in a synthetic growth medium (SGM). The absence of thiamine in SGM yielded no detectable IAA. In summary, this study demonstrates that C. sorokiniana can exude sufficient tryptophan and thiamine to allow IAA production by a PGPB during their interaction. Thiamine is essential for IAA production by A. brasilense and these three metabolites are part of a communication between the two microorganisms. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Influence of amino acid residues near the active site of cytochrome P450 from Bacillus megaterium on the selectivity of n-octane oxidation to octanol regioisomers

    Science.gov (United States)

    Miyaji, Akimitsu; Baba, Toshihide

    2017-09-01

    A mutant of cytochrome P450 from Bacillus megaterium (CYP450BM-3) was prepared by replacing two alanine residues around active site of the enzyme, alanine 328 and alanine 82, with leucine and tryptophan, respectively. The CYP450BM-3 mutant produced 2-octanol selectively from n-octane under atmospheric temperature and pressure; its selectivity was 74%. Furthermore, the mutant produced 1-octanol, which is not produced by wild-type enzyme.

  12. Effects of Ultrasound, Tryptophan and Proline on embryogenesis and regeneration of grape (Vitis vinifera L.

    Directory of Open Access Journals (Sweden)

    Yousef Farokhzad

    2016-10-01

    Full Text Available Genetic improvement of Grape is limited by traditional methods. An effective regeneration system for tissues culture of transgenic adult plants could facilitate genetic modification of them. So it is necessary to develop and improve embryogenesis and regeneration systems in plants. Accordingly the aim of the present study was to evaluate the effects of ultrasound (0 (as control, 60, 120 and 240 second, tryptophan (0 (as control, 50,100, 200 µM and proline content (0 (as control, 50, 100 and 200 µM on grape stem internodes explants in Kodori cultivar. This project was performed in factorial experiment (two factors in the basis of completely randomized design with three replications at tissue culture laboratory of Shahed University of Tehran. Results showed that both ultrasound and two explained amino acids had significant effects on studied characteristics such as callus frequency, callus length and width, fresh weight, embryo numbers in each callus and their germination percentage. Generally, using 100 µM tryptophan and proline coincide with 120 second ultrasound had highest positive effects on the most studied characteristics.

  13. Lack of tryptophan hydroxylase-1 in mice results in gait abnormalities.

    Science.gov (United States)

    Suidan, Georgette L; Duerschmied, Daniel; Dillon, Gregory M; Vanderhorst, Veronique; Hampton, Thomas G; Wong, Siu Ling; Voorhees, Jaymie R; Wagner, Denisa D

    2013-01-01

    The role of peripheral serotonin in nervous system development is poorly understood. Tryptophan hydroxylase-1 (TPH1) is expressed by non-neuronal cells including enterochromaffin cells of the gut, mast cells and the pineal gland and is the rate-limiting enzyme involved in the biosynthesis of peripheral serotonin. Serotonin released into circulation is taken up by platelets via the serotonin transporter and stored in dense granules. It has been previously reported that mouse embryos removed from Tph1-deficient mothers present abnormal nervous system morphology. The goal of this study was to assess whether Tph1-deficiency results in behavioral abnormalities. We did not find any differences between Tph1-deficient and wild-type mice in general motor behavior as tested by rotarod, grip-strength test, open field and beam walk. However, here we report that Tph1 (-/-) mice display altered gait dynamics and deficits in rearing behavior compared to wild-type (WT) suggesting that tryptophan hydroxylase-1 expression has an impact on the nervous system.

  14. IDO chronic immune activation and tryptophan metabolic pathway: A potential pathophysiological link between depression and obesity.

    Science.gov (United States)

    Chaves Filho, Adriano José Maia; Lima, Camila Nayane Carvalho; Vasconcelos, Silvânia Maria Mendes; de Lucena, David Freitas; Maes, Michael; Macedo, Danielle

    2018-01-03

    Obesity and depression are among the most pressing health problems in the contemporary world. Obesity and depression share a bidirectional relationship, whereby each condition increases the risk of the other. By inference, shared pathways may underpin the comorbidity between obesity and depression. Activation of cell-mediated immunity (CMI) is a key factor in the pathophysiology of depression. CMI cytokines, including IFN-γ, TNFα and IL-1β, induce the catabolism of tryptophan (TRY) by stimulating indoleamine 2,3-dioxygenase (IDO) resulting in the synthesis of kynurenine (KYN) and other tryptophan catabolites (TRYCATs). In the CNS, TRYCATs have been related to oxidative damage, inflammation, mitochondrial dysfunction, cytotoxicity, excitotoxicity, neurotoxicity and lowered neuroplasticity. The pathophysiology of obesity is also associated with a state of aberrant inflammation that activates aryl hydrocarbon receptor (AHR), a pathway involved in the detection of intracellular or environmental changes as well as with increases in the production of TRYCATs, being KYN an agonists of AHR. Both AHR and TRYCATS are involved in obesity and related metabolic disorders. These changes in the TRYCAT pathway may contribute to the onset of neuropsychiatric symptoms in obesity. This paper reviews the role of immune activation, IDO stimulation and increased TRYCAT production in the pathophysiology of depression and obesity. Here we suggest that increased synthesis of detrimental TRYCATs is implicated in comorbid obesity and depression and is a new drug target to treat both diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. MUTANT STRAIN of Bacillus subtilis IFBG MC-1 WITH INCREASED TRYPTOPHAN SYNTHESIS

    Directory of Open Access Journals (Sweden)

    A. F. Tkachenko

    2013-12-01

    Full Text Available Scientific research of essential amino acids biotechnology is directed both to create optimum conditions for producer’s cultivation and economically viable raw materials selection for these technologies, so as breeding the more productive microorganisms strains capable of extracellular producing amino acids. For successful microbial synthesis it is necessary to have an excellent crop’s metabolism knowledge and ensure that the composition of growth medium have no repressing substances. Bacterial cultures from «Collection microorganism’s stains and plants line for food and agriculture biotechnology» from Institute of Food Biotechnology and Genomics of National Academy of Sciences of Ukraine have been studied. Tryptophan producer Bacillus subtilis have been selected, which accumulated the greatest amount of this amino acid in the cultivation liquid. The optimal culture producer conditions were selected. Using selection methods, namely mutagenesis with UV irradiation and sequential stepwise selection, mutant strain Bacillus subtilis IFBG MC-1 were obtained which produced nearly 50% more tryptophan (13.9 g/l than the parent strain.

  16. Non-invasive tryptophan fluorescence measurements as a novel method of grading cataract

    DEFF Research Database (Denmark)

    Erichsen, Jesper Høiberg; Mensah, Aurore; Kessel, Line

    2017-01-01

    . All cataracts were age-related. Lens material from 16 eyes of 14 patients was included in the study. Cataracts were preoperatively graded in categories 1, 2 and 3. No lenses were category 4. For nuclear cataracts mean values of F-factor were 52.9 (SD 12.2), 61.7 (SD 5.3) and 75.7 (SD 8.9......) for categories 1, 2 and 3 respectively. Linear regression on F-factor as a function of preoperative grading category showed increasing values of F-factor with increasing preoperative grading category, R2 = 0.515. Our experiment showed that preoperative optical grading of cataracts by Scheimpflug imaging may......Development of non-invasive treatments for cataract calls for a sensitive diagnostic assay. We conducted a study to test whether the ratio of folded tryptophan to non-tryptophan fluorescence emission (F-factor) may be used for grading cataracts in human lenses. The F-factor was measured...

  17. Bright ambient light conditions reduce the effect of tryptophan depletion in healthy females.

    Science.gov (United States)

    Defrancesco, Michaela; Niederstätter, Harald; Parson, Walther; Kemmler, Georg; Hinterhuber, Hartmann; Marksteiner, Josef; Deisenhammer, Eberhard A

    2013-11-30

    Tryptophan depletion (TD) is an established method to influence the serotonergic system and mood. The purpose of this study was to examine the effect of TD under different ambient light conditions, measured through serotonin-associated plasma levels and a visual analog scale (VAS), on healthy females. Thirty-eight healthy female s-allele carriers of the serotonin transporter promoter gene (5-HTTLPR) were administered a TD under dim light conditions (75 lx). A sub-group of 8 participants repeated the procedure randomized in two additional light conditions (585 lx and 1530 lx respectively). Prior to, and 5h following administration of TD, various variables (serotonin-associated plasma levels, VAS) were measured. Due to not normal distributed data, non-parametric statistical tests were used. Overall analysis showed a significant mood lowering effect of TD. Moreover, TD decreased all measured serotonin-associated plasma levels significantly. Significant differences in varying light conditions were found for the VAS and plasma tryptophan, with the greatest effect of TD in the 75 lx condition. Results of our study showed an influence of even slight differences in ambient light intensity on the effect of TD concerning mood as well as on the serotonergic system. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Tryptophan-2,3-dioxygenase (TDO) inhibition ameliorates neurodegeneration by modulation of kynurenine pathway metabolites.

    Science.gov (United States)

    Breda, Carlo; Sathyasaikumar, Korrapati V; Sograte Idrissi, Shama; Notarangelo, Francesca M; Estranero, Jasper G; Moore, Gareth G L; Green, Edward W; Kyriacou, Charalambos P; Schwarcz, Robert; Giorgini, Flaviano

    2016-05-10

    Metabolites of the kynurenine pathway (KP) of tryptophan (TRP) degradation have been closely linked to the pathogenesis of several neurodegenerative disorders. Recent work has highlighted the therapeutic potential of inhibiting two critical regulatory enzymes in this pathway-kynurenine-3-monooxygenase (KMO) and tryptophan-2,3-dioxygenase (TDO). Much evidence indicates that the efficacy of KMO inhibition arises from normalizing an imbalance between neurotoxic [3-hydroxykynurenine (3-HK); quinolinic acid (QUIN)] and neuroprotective [kynurenic acid (KYNA)] KP metabolites. However, it is not clear if TDO inhibition is protective via a similar mechanism or if this is instead due to increased levels of TRP-the substrate of TDO. Here, we find that increased levels of KYNA relative to 3-HK are likely central to the protection conferred by TDO inhibition in a fruit fly model of Huntington's disease and that TRP treatment strongly reduces neurodegeneration by shifting KP flux toward KYNA synthesis. In fly models of Alzheimer's and Parkinson's disease, we provide genetic evidence that inhibition of TDO or KMO improves locomotor performance and ameliorates shortened life span, as well as reducing neurodegeneration in Alzheimer's model flies. Critically, we find that treatment with a chemical TDO inhibitor is robustly protective in these models. Consequently, our work strongly supports targeting of the KP as a potential treatment strategy for several major neurodegenerative disorders and suggests that alterations in the levels of neuroactive KP metabolites could underlie several therapeutic benefits.

  19. Optimization of Photosensitized Tryptophan Oxidation in the Presence of Dimegin-Polyvinylpyrrolidone-Chitosan Systems.

    Science.gov (United States)

    Solovieva, Anna B; Kardumian, Valeria V; Aksenova, Nadezhda A; Belovolova, Lyudmila V; Glushkov, Mikhail V; Bezrukov, Evgeny A; Sukhanov, Roman B; Kotova, Svetlana L; Timashev, Peter S

    2018-05-23

    By the example of a model process of tryptophan photooxidation in the aqueous medium in the presence of a three-component photosensitizing complex (porphyrin photosensitizer-polyvinylpyrrolidone- chitosan, PPS-PVP-CT) in the temperature range of 20-40 °С, we have demonstrated a possibility of modification of such a process by selecting different molar ratios of the components in the reaction mixture. The actual objective of this selection is the formation of a certain PPS-PVP-CT composition in which PVP macromolecules would coordinate with PPS molecules and at the same time practically block the complex binding of PPS molecules with chitosan macromolecules. Such blocking allows utilization of the bactericidal properties of chitosan to a greater extent, since chitosan is known to depress the PPS photosensitizing activity in PPS-PVP-CT complexes when using those in photodynamic therapy (PDT). The optimal composition of photosensitizing complexes appears to be dependent on the temperature at which the PDT sessions are performed. We have analyzed the correlations of the effective rate constants of tryptophan photooxidation with the photophysical characteristics of the formed complexes.

  20. Imaging C. elegans with thiolated tryptophan-based NIR fluorescent gold nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Barman, Apurba Kr. [Indian Institute of Technology Kanpur, Department of Chemistry (India); Chaturbedi, Amaresh; Subramaniam, K. [Indian Institute of Technology Kanpur, Department of Biological Sciences and Bioengineering (India); Verma, Sandeep, E-mail: sverma@iitk.ac.in [Indian Institute of Technology Kanpur, Department of Chemistry (India)

    2013-11-15

    Multidentate, thiolated, tryptophan-containing peptide conjugates were synthesized for the preparation of gold nanoclusters (AuNCs). Precursor Au{sub 11}(PPh{sub 3}){sub 8}Cl{sub 3} was prepared by the reduction of HAuCl{sub 4}, followed by the use of tryptophan-containing peptide conjugates in ligand displacement reactions, to afford near-infrared fluorescent AuNCs. The emission maxima for these newly synthesized AuNCs were ∼715 nm. AuNCs were characterized with the help of UV–Vis, FTIR, fluorescence and MALDI analysis. FTIR spectra showed that the ligands bind to Au atoms through Au–S bonds, while MALDI mass spectra revealed that the clusters consisted of 20–23 Au atoms. Introduction of hydrophilic –COOH groups engendered water solubility to these AuNCs, enabling bioimaging applications. We demonstrate fluorescence imaging of the nematode C. elegans and confirm distribution of these AuNCs in nematode gut with the help of green fluorescent protein co-localization experiments.

  1. CARD9 impacts colitis by altering gut microbiota metabolism of tryptophan into aryl hydrocarbon receptor ligands.

    Science.gov (United States)

    Lamas, Bruno; Richard, Mathias L; Leducq, Valentin; Pham, Hang-Phuong; Michel, Marie-Laure; Da Costa, Gregory; Bridonneau, Chantal; Jegou, Sarah; Hoffmann, Thomas W; Natividad, Jane M; Brot, Loic; Taleb, Soraya; Couturier-Maillard, Aurélie; Nion-Larmurier, Isabelle; Merabtene, Fatiha; Seksik, Philippe; Bourrier, Anne; Cosnes, Jacques; Ryffel, Bernhard; Beaugerie, Laurent; Launay, Jean-Marie; Langella, Philippe; Xavier, Ramnik J; Sokol, Harry

    2016-06-01

    Complex interactions between the host and the gut microbiota govern intestinal homeostasis but remain poorly understood. Here we reveal a relationship between gut microbiota and caspase recruitment domain family member 9 (CARD9), a susceptibility gene for inflammatory bowel disease (IBD) that functions in the immune response against microorganisms. CARD9 promotes recovery from colitis by promoting interleukin (IL)-22 production, and Card9(-/-) mice are more susceptible to colitis. The microbiota is altered in Card9(-/-) mice, and transfer of the microbiota from Card9(-/-) to wild-type, germ-free recipients increases their susceptibility to colitis. The microbiota from Card9(-/-) mice fails to metabolize tryptophan into metabolites that act as aryl hydrocarbon receptor (AHR) ligands. Intestinal inflammation is attenuated after inoculation of mice with three Lactobacillus strains capable of metabolizing tryptophan or by treatment with an AHR agonist. Reduced production of AHR ligands is also observed in the microbiota from individuals with IBD, particularly in those with CARD9 risk alleles associated with IBD. Our findings reveal that host genes affect the composition and function of the gut microbiota, altering the production of microbial metabolites and intestinal inflammation.

  2. Au nanoparticles on tryptophan-functionalized graphene for sensitive detection of dopamine

    International Nuclear Information System (INIS)

    Lian, Qianwen; Luo, Ai; An, Zhenzhen; Li, Zhuang; Guo, Yongyang; Zhang, Dongxia; Xue, Zhonghua; Zhou, Xibin; Lu, Xiaoquan

    2015-01-01

    Graphical abstract: - Highlights: • A novel AuNPs/Trp-GR composite was fabricated by directly electrochemical deposition. • The composite exhibited excellent electrocatalytic activity towards DA. • The proposed method was applied to real samples. - Abstract: A novel and uniform gold nanoparticles/tryptophan-functionalized graphene nanocomposite (AuNPs/Trp-GR) has been successfully fabricated by directly electrochemical depositing gold onto the surface of tryptophan-functionalized graphene (Trp-GR). The nanostructure of AuNPs/Trp-GR was characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). It was demonstrated that Au nanoparticles were well dispersed on the surface of Trp-GR which might attribute to the more binding sites provided by Trp-GR for the formation of Au nanoparticles. The electrocatalytic activity of the AuNPs/Trp-GR towards the dopamine (DA) was systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, a wide and valuable linear range (0.5–411 μM), a low detection limit (0.056 μM, S/N = 3), good repeatability and stability were obtained for the determination of DA. Furthermore, the modified electrode was successfully applied to real samples analysis

  3. Au nanoparticles on tryptophan-functionalized graphene for sensitive detection of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Qianwen; Luo, Ai; An, Zhenzhen; Li, Zhuang; Guo, Yongyang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, 730070, Lanzhou (China); Xue, Zhonghua [College of Chemistry and Chemical Engineering, Northwest Normal University, 730070, Lanzhou (China); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, 730070, Lanzhou (China); Lu, Xiaoquan, E-mail: Luxq@nwnu.edu.cn [College of Chemistry and Chemical Engineering, Northwest Normal University, 730070, Lanzhou (China)

    2015-09-15

    Graphical abstract: - Highlights: • A novel AuNPs/Trp-GR composite was fabricated by directly electrochemical deposition. • The composite exhibited excellent electrocatalytic activity towards DA. • The proposed method was applied to real samples. - Abstract: A novel and uniform gold nanoparticles/tryptophan-functionalized graphene nanocomposite (AuNPs/Trp-GR) has been successfully fabricated by directly electrochemical depositing gold onto the surface of tryptophan-functionalized graphene (Trp-GR). The nanostructure of AuNPs/Trp-GR was characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). It was demonstrated that Au nanoparticles were well dispersed on the surface of Trp-GR which might attribute to the more binding sites provided by Trp-GR for the formation of Au nanoparticles. The electrocatalytic activity of the AuNPs/Trp-GR towards the dopamine (DA) was systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, a wide and valuable linear range (0.5–411 μM), a low detection limit (0.056 μM, S/N = 3), good repeatability and stability were obtained for the determination of DA. Furthermore, the modified electrode was successfully applied to real samples analysis.

  4. The role of oligomerization and cooperative regulation in protein function: the case of tryptophan synthase.

    Directory of Open Access Journals (Sweden)

    M Qaiser Fatmi

    Full Text Available The oligomerization/co-localization of protein complexes and their cooperative regulation in protein function is a key feature in many biological systems. The synergistic regulation in different subunits often enhances the functional properties of the multi-enzyme complex. The present study used molecular dynamics and Brownian dynamics simulations to study the effects of allostery, oligomerization and intermediate channeling on enhancing the protein function of tryptophan synthase (TRPS. TRPS uses a set of α/β-dimeric units to catalyze the last two steps of L-tryptophan biosynthesis, and the rate is remarkably slower in the isolated monomers. Our work shows that without their binding partner, the isolated monomers are stable and more rigid. The substrates can form fairly stable interactions with the protein in both forms when the protein reaches the final ligand-bound conformations. Our simulations also revealed that the α/β-dimeric unit stabilizes the substrate-protein conformation in the ligand binding process, which lowers the conformation transition barrier and helps the protein conformations shift from an open/inactive form to a closed/active form. Brownian dynamics simulations with a coarse-grained model illustrate how protein conformations affect substrate channeling. The results highlight the complex roles of protein oligomerization and the fine balance between rigidity and dynamics in protein function.

  5. Tryptophan: the key to boosting brain serotonin synthesis in depressive illness.

    Science.gov (United States)

    Badawy, Abdulla A-B

    2013-10-01

    It has been proposed that focusing on brain serotonin synthesis can advance antidepressant drug development. Biochemical aspects of the serotonin deficiency in major depressive disorder (MDD) are discussed here in detail. The deficiency is caused by a decreased availability of the serotonin precursor tryptophan (Trp) to the brain. This decrease is caused by accelerated Trp degradation, most likely induced by enhancement of the hepatic enzyme tryptophan 2,3-dioxygenase (TDO) by glucocorticoids and/or catecholamines. Induction of the extrahepatic Trp-degrading enzyme indolylamine 2,3-dioxygenase (IDO) by the modest immune activation in MDD has not been demonstrated and, if it occurs, is unlikely to make a significant contribution. Liver TDO appears to be a target of many antidepressants, the mood stabilisers Li(+) and carbamazepine and possibly other adjuncts to antidepressant therapy. The poor, variable and modest antidepressant efficacy of Trp is due to accelerated hepatic Trp degradation, and efficacy can be restored or enhanced by combination with antidepressants or other existing or new TDO inhibitors. Enhancing Trp availability to the brain is thus the key to normalisation of serotonin synthesis and could form the basis for future antidepressant drug development.

  6. EFFECT OF DIETARY TRYPTOPHAN LEVELS ON GROWTH PERFORMANCE OF BROILER CHICKENS REARED IN THE HOT SEASON UNDER TROPICAL ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Emmanuel Opoola

    2017-12-01

    Full Text Available This study was conducted to evaluate the effect of dietary levels of tryptophan on growth performance of broiler chickens reared under tropical environment. At the starter phase, a total of two hundred and eighty five day old mixed sex Arbor Acres broiler chicks were randomly allotted to five dietary treatments with three replicates each having nineteen (19 chicks. At the finisher phase, two hundred and seventy broilers were also allotted to five dietary treatments with three replicates each having 18 broilers per replicate. The dietary tryptophan levels at the starter phase were 0.15, 0.19, 0.23, 0.27 and 0.31% respectively while the diets for the finisher phase contained 0.13, 0.17, 0.21, 0.25 and 0.29% dietary tryptophan respectively. All other nutrient levels were constant. The experiment was conducted at 0 to 28d (starter phase and 33 to 56d (finisher phase. Growth performance traits including weight gain, feed intake and feed conversion ratio were recorded at the end of each week. The results for the starter phase showed that chicks fed diet containing 0.23%, 0.27% and 0.31% dietary tryptophan had similar results in term of the weight gain, average daily weight gain, feed intake and average daily feed intake. For the finisher phase, the birds fed 0.21%, 0.25% and 0.29% tryptophan diets also had similar results in terms of final weight, weight gain, feed intake and average daily feed intake. Our results suggest that supplemental tryptophan was sufficient to have significant (P<0.05 effect on broiler performance. However, polynomial regression analysis reveals that the optimum performances were reached at 0.24% and 0.21% dietary tryptophan for the starter and finisher phases respectively. Therefore, it can be concluded that dietary tryptophan requirements during the hot season for the starter and finisher phases were 0.24% and 0.21%, respectively.

  7. Highly specific ''sensing'' of tryptophan by a luminescent europium(III) complex

    Energy Technology Data Exchange (ETDEWEB)

    Stubenrauch, Jan A.; Mevissen, Christian; Schulte, Marie F.; Bochenek, Steffen; Albrecht, Markus [RWTH Univ. Aachen (Germany). Inst. fuer Organische Chemie; Subramanian, Palani S. [Central Salt and Marine Chemicals, Research Institute (CSRI), Gujarat (India)

    2016-07-01

    The europium(III) complex 1-Cl{sub 3} (S,S-2,2{sup '}-(((1,10-phenanthroline-2,9-diyl)bis(methanylylidene))bis (azanylyliden e))bis(3-methylbutanamide)europiumtrichloride) undergoes, only in the presence of the amino acid tryptophan, a change of emission at 615 nm. In the presence of few equivalents of tryptophan, emission of the europium complex is enhanced while it disappears upon addition of large amounts. This behavior can be assigned to displacement of the sensitizing phenanthroline ligand of 1-Cl{sub 2} x Trp in the latter case.

  8. Metabolic Availability of the Limiting Amino Acids Lysine and Tryptophan in Cooked White African Cornmeal Assessed in Healthy Young Men Using the Indicator Amino Acid Oxidation Technique.

    Science.gov (United States)

    Rafii, Mahroukh; Elango, Rajavel; Ball, Ronald O; Pencharz, Paul B; Courtney-Martin, Glenda

    2018-06-01

    Maize is a staple food in many regions of the world, particularly in Africa and Latin America. However, maize protein is limiting in the indispensable amino acids lysine and tryptophan, making its protein of poor quality. The main objective of this study was to determine the protein quality of white African cornmeal by determining the metabolic availability (MA) of lysine and tryptophan. To determine the MA of lysine, 4 amounts of l-lysine (10, 13, 16, and 18 mg · kg-1 · d-1 totaling 28.6%, 37.1%, 45.7%, and 51.4% of the mean lysine requirement of 35 mg · kg-1 · d-1, respectively) were studied in 6 healthy young men in a repeated-measures design. To determine the MA of tryptophan, 4 amounts of l-tryptophan (0.5, 1, 1.5, and 2 mg · kg-1 · d-1 totaling 12.5%, 25.0%, 37.5%, and 50.0% of the mean tryptophan requirement of 4 mg · kg-1 · d-1, respectively) were studied in 7 healthy young men in a repeated-measures design. The MAs of lysine and tryptophan were estimated by comparing the indicator amino acid oxidation (IAAO) response with varying intakes of lysine and tryptophan in cooked white cornmeal compared with the IAAO response to l-lysine and l-tryptophan intakes in the reference protein (crystalline amino acid mixture patterned after egg protein) with the use of the slope ratio method. The MAs of lysine and tryptophan from African cooked white cornmeal were 71% and 80%, respectively. Our study provides a robust estimate of the availability of lysine and tryptophan in African white maize to healthy young men. This estimate provides a basis for postproduction fortification or supplementation of maize-based diets. This trial was registered at www.clinicaltrials.gov as NCT02402179.

  9. Handling of Solid Residues

    International Nuclear Information System (INIS)

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  10. Surplus dietary tryptophan reduces plasma cortisol and noradrenaline concentrations and enhances recovery after social stress in pigs

    NARCIS (Netherlands)

    Koopmans, S.J.; Ruis, M.A.W.; Dekker, R.A.; Diepen, van J.T.M.; Korte, S.M.; Mroz, Z.

    2005-01-01

    Social stress occurs in intensive pig farming due to aggressive behavior. This stress may be reduced at elevated dietary levels of tryptophan (TRP). In this study, we compared the effects of high (13.2%) vs. normal (3.4%) dietary TRP to large neutral amino acid (LNAA) ratios on behavior and stress

  11. Evaluation of acute tryptophan depletion and sham depletion with a gelatin-based collagen peptide protein mixture

    DEFF Research Database (Denmark)

    Stenbæk, Dea Siggaard; Einarsdottir, H S; Goregliad-Fjaellingsdal, T

    2016-01-01

    Acute Tryptophan Depletion (ATD) is a dietary method used to modulate central 5-HT to study the effects of temporarily reduced 5-HT synthesis. The aim of this study is to evaluate a novel method of ATD using a gelatin-based collagen peptide (CP) mixture. We administered CP-Trp or CP+Trp mixtures...

  12. Metabolic pathway interruption: CRISPR/Cas9-mediated knockout of tryptophan 2,3-oxygenase in Tribolium castaneum

    Science.gov (United States)

    The Tribolium castaneum vermilion gene encodes tryptophan 2,3-dioxygenase, a pivotal enzyme in the ommochrome pathway that is responsible for the black eye color. T. castaneum strains with a loss-of-function mutation, vermilion white (vw), lack both the promoter and the first 80% of the vermilion co...

  13. Neural and personality correlates of individual differences related to the effects of acute tryptophan depletion on future reward evaluation.

    Science.gov (United States)

    Demoto, Yoshihiko; Okada, Go; Okamoto, Yasumasa; Kunisato, Yoshihiko; Aoyama, Shiori; Onoda, Keiichi; Munakata, Ayumi; Nomura, Michio; Tanaka, Saori C; Schweighofer, Nicolas; Doya, Kenji; Yamawaki, Shigeto

    2012-01-01

    In general, humans tend to discount the value of delayed reward. An increase in the rate of discounting leads to an inability to select a delayed reward over a smaller immediate reward (reward-delay impulsivity). Although deficits in the serotonergic system are implicated in this reward-delay impulsivity, there is individual variation in response to serotonin depletion. The aim of the present study was to investigate whether the effects of serotonin depletion on the ability to evaluate future reward are affected by individual personality traits or brain activation. Personality traits were assessed using the NEO-Five Factor Inventory and Temperament and Character Inventory. The central serotonergic levels of 16 healthy volunteers were manipulated by dietary tryptophan depletion. Subjects performed a delayed reward choice task that required the continuous estimation of reward value during functional magnetic resonance imaging scanning. Discounting rates were increased in 9 participants, but were unchanged or decreased in 7 participants in response to tryptophan depletion. Participants whose discounting rate was increased by tryptophan depletion had significantly higher neuroticism and lower self-directedness. Furthermore, tryptophan depletion differentially affected the groups in terms of hemodynamic responses to the value of predicted future reward in the right insula. These results suggest that individuals who have high neuroticism and low self-directedness as personality traits are particularly vulnerable to the effect of low serotonin on future reward evaluation accompanied by altered brain activation patterns. Copyright © 2012 S. Karger AG, Basel.

  14. Evening dietary tryptophan improves post-sleep behavioral and brain measures of memory function in healthy subjects

    NARCIS (Netherlands)

    Markus, C.R.; Jonkman, L.M.; Lammers, J.H.C.M.; Deutz, N.E.P.

    2006-01-01

    Brain serotonin function has been implicated in the control of sleep and sleep related memory dysfunctions are attributed to deficient brain serotonin activity. Depletion of the serotonin precursor tryptophan reduces brain serotonin function and is found to cause sleep abnormalities and cognitive

  15. Indoleamine 2,3-dioxygenase-dependent tryptophan metabolites contribute to tolerance induction during allergen immunotherapy in a mouse model

    NARCIS (Netherlands)

    Taher, Yousef A.; Piavaux, Benoit J. A.; Gras, Renee; van Esch, Betty C. A. M.; Hofman, Gerard A.; Bloksma, Nanne; Henricks, Paul A. J.; van Oosterhout, Antoon J. M.

    Background: The tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) has been implicated in immune suppression and tolerance induction. Objective: We examined (1) whether IDO activity is required during tolerance induction by allergen immunotherapy or for the subsequent suppressive

  16. Adsorption of the cysteine–tryptophan dipeptide at the Au(110)/liquid interface studied using reflection anisotropy spectroscopy

    DEFF Research Database (Denmark)

    Morozzo della Rocca, Blasco; Smith, C I; Tesauro, Cinzia

    2010-01-01

    The adsorption of a cysteine–tryptophan dipeptide has been monitored at a Au(110)/electrolyte interface using reflection anisotropy spectroscopy. At −0.6 V the dipeptide adsorbed through the formation of Au–S bonds and a link between the NH2 group at the Au surface. As the applied potential...

  17. Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

    KAUST Repository

    Rydberg, Hanna A

    2014-04-18

    Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

  18. Synthesis and biological evaluation of ¹⁸F-labeled fluoropropyl tryptophan analogs as potential PET probes for tumor imaging.

    Science.gov (United States)

    Chiotellis, Aristeidis; Mu, Linjing; Müller, Adrienne; Selivanova, Svetlana V; Keller, Claudia; Schibli, Roger; Krämer, Stefanie D; Ametamey, Simon M

    2013-01-01

    In the search for an efficient, fluorine-18 labeled amino acid based radiotracer for tumor imaging with positron emission tomography (PET), two new tryptophan analogs were synthesized and characterized in vitro and in vivo. Both are tryptophan alkyl-derivatives, namely 2-(3-[(18)F]fluoropropyl)-DL-tryptophan ([(18)F]2-FPTRP) and 5-(3-[(18)F]fluoro-propyl)-DL-tryptophan ([(18)F]5-FPTRP). Standard reference compounds and precursors were prepared by multi step approaches. Radiosynthesis was achieved by no-carrier-added nucleophilic [(18)F]fluorination in 29-34% decay corrected yields with radiochemical purity over 99%. In vitro cell uptake assays showed that both compounds are substrates for amino acid transport and enter small cell lung cancer cells (NCI-H69) most probably almost exclusively via large neutral amino acids transporter(s) (LAT). Small animal PET imaging with xenograft bearing mice revealed high tumor/background ratios for [(18)F]2-FPTRP comparable to the well established tyrosine analog O-(2-[(18)F]fluroethyl)-L-tyrosine ([(18)F]FET). Radiometabolite studies showed no evidence of involvement of a biotransformation step in tumor accumulation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  19. Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

    KAUST Repository

    Rydberg, Hanna A; Kunze, Angelika; Carlsson, Nils; Altgä rde, Noomi; Svedhem, Sofia; Nordé n, Bengt

    2014-01-01

    Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

  20. Preparation and characterization of a novel epoxy based nanocomposite using tryptophan as an eco-friendly curing agent

    International Nuclear Information System (INIS)

    Motahari, Ahmad; Omrani, Abdollah; Rostami, Abbas Ali; Ehsani, Morteza

    2013-01-01

    Highlights: • Epoxy cured with tryptophan in the presence of 2,4,5-triphenylimidazole. • Kinetic study on the epoxy nanocomposite using advanced isoconversional method. • Structural study and characterization of nanocomposite using SEM, XRD, AFM and DMTA. - Abstract: In this study, kinetics of the curing reaction between DGEBA epoxy resin and tryptophan as an environmentally friendly curing agent in the presence of 2,4,5-triphenylimidazole was reported. The role of silica nanoparticles (SiNP) in changing the mechanism of the curing reaction was also studied. The optimum molar ratio of DGEBA/tryptophan and the optimum content of SiNP were determined by calorimetry analyses. Kinetic analysis using the advanced isoconversional method revealed that the system undergoes the vitrification. Thermogravimetric analysis demonstrated that addition of SiNP does not improve the thermal stability of the tryptophan based thermosets. Impedance spectroscopy and also the standard four-probe method were performed to investigate the effect of curing agent and SiNP loading level on the electrical properties of the cured epoxy. The structure and morphology of the nanocomposite were studied by X-ray diffraction analysis, atomic force microscopy and scanning electron microscopy imaging. Dynamic mechanical thermal analysis revealed that the crosslinking density cannot be significantly affected with the addition of SiNP

  1. Site-directed Mutagenesis Switching a Dimethylallyl Tryptophan Synthase to a Specific Tyrosine C3-Prenylating Enzyme*

    Science.gov (United States)

    Fan, Aili; Zocher, Georg; Stec, Edyta; Stehle, Thilo; Li, Shu-Ming

    2015-01-01

    The tryptophan prenyltransferases FgaPT2 and 7-DMATS (7-dimethylallyl tryptophan synthase) from Aspergillus fumigatus catalyze C4- and C7-prenylation of the indole ring, respectively. 7-DMATS was found to accept l-tyrosine as substrate as well and converted it to an O-prenylated derivative. An acceptance of l-tyrosine by FgaPT2 was also observed in this study. Interestingly, isolation and structure elucidation revealed the identification of a C3-prenylated l-tyrosine as enzyme product. Molecular modeling and site-directed mutagenesis led to creation of a mutant FgaPT2_K174F, which showed much higher specificity toward l-tyrosine than l-tryptophan. Its catalytic efficiency toward l-tyrosine was found to be 4.9-fold in comparison with that of non-mutated FgaPT2, whereas the activity toward l-tryptophan was less than 0.4% of that of the wild-type. To the best of our knowledge, this is the first report on an enzymatic C-prenylation of l-tyrosine as free amino acid and altering the substrate preference of a prenyltransferase by mutagenesis. PMID:25477507

  2. Radiation-induced mutagenicity and lethality in tryptophan-requiring auxotrophs of escherichia coli

    International Nuclear Information System (INIS)

    Xu Rong; Qian Hongwei; Yao Fenying; Gu Shuzhu; Xu Jiaxin; Bi Hekan; Liu Yuying

    1989-01-01

    Mutation and killing caused by X-ray radiation and 60 Co γ-ray radiation were studied in three different tryptophan-requiring auxotrophs (WP2, Wp2A, Cm 891) of Escherichia coli. These testers are sensitive to base pair substitution mutagens. Cm891 carries a R-factor and is more sensitive than WP2 and WP2A to radiation-induced mutation and lethality. The results of the study show that (1) ionizing radiation was mutagenic to E. coli, (2) the order of mutagenic sensitivity among three strains to ionizing radiation was Cm891 > WP2A > WP2, (3) the dose rate of γ-ray influences mutagenicity and lethalty of E. coli strain, (4) the toxicity and mutagenicity of γ-ray were similar to X-ray when Cm891 was tested, however, γ-ray was more toxic and mutagenic than X-ray to WP2A ang WP2

  3. Effect of Tryptophan on the corrosion behavior of low alloy steel in sulfamic acid

    Directory of Open Access Journals (Sweden)

    Hesham T.M. Abdel-Fatah

    2016-11-01

    Full Text Available Sulfamic acid is widely used in various industrial acid cleaning applications. In the present work, the inhibition effect of Tryptophan (Tryp on the corrosion of low alloy steel in sulfamic acid solutions at four different temperatures was studied. The investigations involved electrochemical methods (electrochemical impedance spectroscopy; EIS and the new technique electrochemical frequency modulation; EFM as well as gravimetric measurements. The inhibition efficiency and the apparent activation energy have been calculated in the presence and in the absence of Tryp. It is most probable that the inhibition property of Tryp was due to the electrostatic adsorption of the protonated form of Tryp on the steel surface. Adsorption of the inhibitor molecule, onto the steel surface followed the Temkin adsorption isotherm. The thermodynamic parameters of adsorption were determined and discussed. All of the obtained data from the three techniques were in close agreement, which confirmed that EFM technique can be used efficiently for monitoring the corrosion inhibition under the studied conditions.

  4. Estradiol or fluoxetine alters depressive behavior and tryptophan hydroxylase in rat raphe.

    Science.gov (United States)

    Yang, Fu-Zhong; Wu, Yan; Zhang, Wei-Guo; Cai, Yi-Yun; Shi, Shen-Xun

    2010-03-10

    The effects of 17beta-estradiol and fluoxetine on behavior of ovariectomized rats subjected to the forced swimming test and the expression of tryptophan hydroxylase (TPH) in dorsal and median raphe were investigated, respectively through time sampling technique of behavior scoring and immunohistochemistry. Both estradiol and fluoxetine increased swimming and decreased immobility in the forced swimming test. The forced swimming stress decreased integrated optical density of TPH-positive regions in dorsal and median raphe. Both estradiol and fluoxetine administration prevented integrated optical density of TPH-positive regions from being decreased by forced swimming stress. These observations suggest that both estradiol and fluoxetine have protective bearing on ovariectomized rats enduring forced swimming stress.

  5. Kinetics of immobilisation and release of tryptophan, riboflavin and peptides from whey protein microbeads.

    Science.gov (United States)

    O'Neill, Graham J; Egan, Thelma; Jacquier, Jean Christophe; O'Sullivan, Michael; Dolores O'Riordan, E

    2015-08-01

    This study investigated the kinetics of immobilisation and release of riboflavin, amino acids and peptides from whey microbeads. Blank whey microbeads were placed in solutions of the compounds. As the volume of microbeads added to the solution was increased, the uptake of the compounds increased, to a maximum of 95% for the pentapeptide and 56%, 57% and 45% for the dipeptide, riboflavin and tryptophan respectively, however, the rate of uptake remained constant. The rate of uptake increased with increasing molecule hydrophobicity. The opposite was observed in the release studies, the more hydrophobic compounds had lower release rate constants (kr). When whey microbeads are used as sorbents, they show excellent potential to immobilise small hydrophobic molecules and minimise subsequent diffusion, even in high moisture environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Biocatalytic production of psilocybin and derivatives in tryptophan synthase-enhanced reactions.

    Science.gov (United States)

    Blei, Felix; Baldeweg, Florian; Fricke, Janis; Hoffmeister, Dirk

    2018-05-11

    Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine) is the main alkaloid of the fungal genus Psilocybe, the so-called "magic mushrooms". The pharmaceutical interest in this psychotropic natural product as a future medication to treat depression and anxiety is strongly re-emerging. Here, we present an enhanced enzymatic route of psilocybin production by adding TrpB, the tryptophan synthase of the mushroom Psilocybe cubensis, to the reaction. We capitalized on its substrate flexibility and show psilocybin formation from 4-hydroxyindole and L-serine, which are less cost-intensive substrates, compared to the previous method. Further, we show enzymatic production of 7-phosphoryloxytryptamine (isonorbaeocystin), a non-natural congener of the Psilocybe alkaloid norbaeocystin (4-phosphoryloxytryptamine), and of serotonin (5-hydroxytryptamine) via the same in vitro approach. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Role of NAD, Oxidative Stress, and Tryptophan Metabolism in Autism Spectrum Disorders

    Directory of Open Access Journals (Sweden)

    Musthafa Mohamed Essa

    2013-01-01

    Full Text Available Autism spectrum disorder (ASD is a pervasive neuro-developmental disorder characterized by impaired social interaction, reduced/absent verbal and non-verbal communication, and repetitive behavior during early childhood. The etiology of this developmental disorder is poorly understood, and no biomarkers have been identified. Identification of novel biochemical markers related to autism would be advantageous for earlier clinical diagnosis and intervention. Studies suggest that oxidative stress-induced mechanisms and reduced antioxidant defense, mitochondrial dysfunction, and impaired energy metabolism (NAD + , NADH, ATP, pyruvate, and lactate, are major causes of ASD. This review provides renewed insight regarding current autism research related to oxidative stress, mitochondrial dysfunction, and altered tryptophan metabolism in ASD.

  8. To Cheat or Not To Cheat: Tryptophan Hydroxylase 2 SNP Variants Contribute to Dishonest Behavior.

    Science.gov (United States)

    Shen, Qiang; Teo, Meijun; Winter, Eyal; Hart, Einav; Chew, Soo H; Ebstein, Richard P

    2016-01-01

    Although, lying (bear false witness) is explicitly prohibited in the Decalogue and a focus of interest in philosophy and theology, more recently the behavioral and neural mechanisms of deception are gaining increasing attention from diverse fields especially economics, psychology, and neuroscience. Despite the considerable role of heredity in explaining individual differences in deceptive behavior, few studies have investigated which specific genes contribute to the heterogeneity of lying behavior across individuals. Also, little is known concerning which specific neurotransmitter pathways underlie deception. Toward addressing these two key questions, we implemented a neurogenetic strategy and modeled deception by an incentivized die-under-cup task in a laboratory setting. The results of this exploratory study provide provisional evidence that SNP variants across the tryptophan hydroxylase 2 (TPH2) gene, that encodes the rate-limiting enzyme in the biosynthesis of brain serotonin, contribute to individual differences in deceptive behavior.

  9. To cheat or not to cheat: Tryptophan hydroxylase 2 SNP variants contribute to dishonest behavior

    Directory of Open Access Journals (Sweden)

    Qiang eShen

    2016-05-01

    Full Text Available Although lying (bear false witness is explicitly prohibited in the Decalogue and a focus of interest in philosophy and theology, more recently the behavioral and neural mechanisms of deception are gaining increasing attention from diverse fields especially economics, psychology and neuroscience. Despite the considerable role of heredity in explaining individual differences in deceptive behavior, few studies have investigated which specific genes contribute to the heterogeneity of lying behavior across individuals. Also, little is known concerning which specific neurotransmitter pathways underlie deception. Towards addressing these two key questions, we implemented a neurogenetic strategy and modeled deception by an incentivized die-under-cup task in a laboratory setting. The results of this exploratory study provide provisional evidence that SNP variants across the tryptophan hydroxylase 2 (TPH2 gene, that encodes the rate-limiting enzyme in the biosynthesis of brain serotonin, contribute to individual differences in deceptive behavior.

  10. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  11. Certain tryptophan photoproducts are inhibitors of cytochrome P450-dependent mutagenicity

    International Nuclear Information System (INIS)

    Rannug, U.; Agurell, E.; Cederberg, H.; Rannug, A.

    1992-01-01

    Two photoproducts, derived from UV-irradiation of the amino acid L-tryptophan and with high Ah (TCDD) receptor binding affinity, were tested for genotoxic and antimutagenic effects. The two indolo[3,2-b]carbazole derivatives, with the molecular weights of 284 and 312, respectively, were tested in Saccharomyces cerevisiae strain D7 for mitotic gene conversion and reverse mutation and in strain RS112 for sister chromatid conversion and gene conversion. No significant (P > 0.05) genotoxic effects were found in strain D7, while strain RS112 showed a small but significant increase in the frequency of sister chromatid conversions. In Chinese hamster ovary (CHO) cells the two compounds induced a statistically significant but less than twofold increase in the frequency of sister chromatid exchanges (SCE). No mutations were detected when the compounds were tested in Salmonella tphimurium strains TA98 and TA100. However, both 284 and 312 acted as antimutagens on strain TA100+S9 in the presence of benzo(a)pyrene. The decrease in mutagenicity by the most potent compound 284 was 20 revertants/nmol. This effect could be explained by an inhibitory effect on the cytochrome P450-dependent ethoxyresorufin O-deethylase (EROD) activity as seen in rat hepatocytes. The two compounds were also tested with hamster cells expressing rat cytochrome P-4501A1. The results support the conclusion that this cytochrome P-450 isozyme is inhibited by the tryptophan photoproducts. Similar results were also seen with two other high affinity Ah receptor ligands the quinazolinocarboline alkaloids rutaecapine and dehydrorutaecarpine. 20 refs., 3 figs., 4 tabs

  12. In situ tryptophan-like fluorometers: assessing turbidity and temperature effects for freshwater applications.

    Science.gov (United States)

    Khamis, K; Sorensen, J P R; Bradley, C; Hannah, D M; Lapworth, D J; Stevens, R

    2015-04-01

    Tryptophan-like fluorescence (TLF) is an indicator of human influence on water quality as TLF peaks are associated with the input of labile organic carbon (e.g. sewage or farm waste) and its microbial breakdown. Hence, real-time measurement of TLF could be particularly useful for monitoring water quality at a higher temporal resolution than available hitherto. However, current understanding of TLF quenching/interference is limited for field deployable sensors. We present results from a rigorous test of two commercially available submersible tryptophan fluorometers (ex ∼ 285, em ∼ 350). Temperature quenching and turbidity interference were quantified in the laboratory and compensation algorithms developed. Field trials were then undertaken involving: (i) an extended deployment (28 days) in a small urban stream; and, (ii) depth profiling of an urban multi-level borehole. TLF was inversely related to water temperature (regression slope range: -1.57 to -2.50). Sediment particle size was identified as an important control on the turbidity specific TLF response, with signal amplification apparent 200 NTU for clay particles. Compensation algorithms significantly improved agreement between in situ and laboratory readings for baseflow and storm conditions in the stream. For the groundwater trial, there was an excellent agreement between laboratory and raw in situ TLF; temperature compensation provided only a marginal improvement, and turbidity corrections were unnecessary. These findings highlight the potential utility of real time TLF monitoring for a range of environmental applications (e.g. tracing polluting sources and monitoring groundwater contamination). However, in situations where high/variable suspended sediment loads or rapid changes in temperature are anticipated concurrent monitoring of turbidity and temperature is required and site specific calibration is recommended for long term, surface water monitoring.

  13. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    International Nuclear Information System (INIS)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia; Lu, Xiaoquan; Zhou, Xibin

    2014-01-01

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis

  14. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China); Lu, Xiaoquan, E-mail: Luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070 (China); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China)

    2014-05-01

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis.

  15. Ruminal tryptophan-utilizing bacteria degrade ergovaline from tall fescue seed extract.

    Science.gov (United States)

    Harlow, B E; Goodman, J P; Lynn, B C; Flythe, M D; Ji, H; Aiken, G E

    2017-02-01

    The objectives of this study were to evaluate degradation of ergovaline in a tall fescue [ (Schreb.) Darbysh.] seed extract by rumen microbiota ex vivo and to identify specific bacteria capable of ergovaline degradation in vitro. Rumen cell suspensions were prepared by harvesting rumen fluid from fistulated wether goats ( = 3), straining, and differential centrifugation. Suspensions were dispensed into anaerobic tubes with added Trypticase with or without extract (∼10 μg kg ergovaline). Suspensions were incubated for 48 h at 39°C. Samples were collected at 0, 24, and 48 h for ergovaline analysis and enumeration of hyper-ammonia producing (HAB) and tryptophan-utilizing bacteria. Ergovaline values were analyzed by repeated measures using the mixed procedure of SAS. Enumeration data were log transformed for statistical analysis. When suspensions were incubated with extract, 11 to 15% of ergovaline disappearance was observed over 48 h ( = 0.02). After 24 h, suspensions with added extract had 10-fold less HAB than controls ( = 0.04), but treatments were similar by 48 h ( = 1.00). However, after 24 h and 48 h, suspensions with extract had 10-fold more tryptophan-utilizing bacteria ( rumen pure cultures ( JB1, B159, HD4, B, F, MD1, SR) were evaluated for the ability to degrade ergovaline in vitro. Pure culture cell suspensions were incubated as described above and samples were taken at 0 and 48 h for ergovaline analysis. Data were analyzed using the ANOVA procedure of SAS. All HAB, including the isolates, tested degraded ergovaline (54 to 75%; bacteria tested did not degrade ergovaline. The results of this study indicate which rumen bacteria may play an important role in ergovaline degradation and that microbiological strategies for controlling their activity could have ramifications for fescue toxicosis and other forms of ergotism in ruminants.

  16. Positron emission tomographic studies on aromatic L-amino acid decarboxylase activity in vivo for L-dopa and 5-hydroxy-L-tryptophan in the monkey brain

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig, P; Tedroff, J; Lindner, K J; Bjurling, P; Chang, C W; Laangstroem, B [Uppsala Univ. (Sweden); Tsukada, H [Central Research Lab., Hamamatsu Photonics Shizuoka, Osaka (Japan); Watanabe, Y [Dept. of Neuroscience, Osaka Bioscience Inst., Osaka (Japan)

    1993-01-01

    The regional brain kinetics following 5-hydroxy-L-([beta]-11 C)tryptophan and L-([beta]-11 C)DOPA intravenous injection was measured in twelve Rhesus monkeys using positron emission tomography (PET). The radiolabelled compounds were also injected together with various doses of unlabelled 5-hydroxy-L-tryptophan or L-DOPA. The radioactivity accumulated in the striatal region and the rate of increased utilization with time was calculated using a graphical method with back of the brain as a reference region. The rate constants for decarboxylation were 0.0070 [+-] 0.0007 (S. D) and 0.0121 [+-] 0.0010 min[sup -1] for 5-hydroxy-L-([beta]-11 C)tryptophan and L-([beta]-11 C)DOPA, respectively. After concomitant injection with unlabelled 5-hydroxy-L-tryptophan, the rate constant of 5-hydroxy-L-([beta]-11 C)tryptophan decreased dose-dependently and a 50 percent reduction was seen with a dose of about 4 mg/kg of unlabelled compound. A decreased utilization rate of L-([beta]-11 C)DOPA was seen only after simultaneous injection of 30 mg/kg of either L-DOPA or 5-hydroxy-L-tryptophan. This capacity limitation was most likely interpreted as different affinity of the striatal aromatic amino acid decarboxylase for L-DOPA and 5-hydroxy-L-tryptophan, respectively.

  17. Interactions of a didomain fragment of the Drosophila Sex-lethal protein with single-stranded uridine-rich oligoribonucleotides derived from the transformer and Sex-lethal messenger RNA precursors: NMR with residue-selective [5-2H]uridine substitutions

    International Nuclear Information System (INIS)

    Kim, Insil; Muto, Yutaka; Watanabe, Satoru; Kitamura, Aya; Futamura, Yasuhiro; Yokoyama, Shigeyuki; Hosono, Kazumi; Kawai, Gota; Takaku, Hiroshi; Dohmae, Naoshi; Takio, Koji; Sakamoto, Hiroshi; Shimura, Yoshiro

    2000-01-01

    Proteins that contain two or more copies of the RNA-binding domain [ribonucleoprotein (RNP) domain or RNA recognition motif (RRM)] are considered to be involved in the recognition of single-stranded RNA, but the mechanisms of this recognition are poorly understood at the molecular level. For an NMR analysis of a single-stranded RNA complexed with a multi-RBD protein, residue-selective stable-isotope labeling techniques are necessary, rather than common assignment methods based on the secondary structure of RNA. In the present study, we analyzed the interaction of a Drosophila Sex-lethal (Sxl) protein fragment, consisting of two RBDs (RBD1-RBD2), with two distinct target RNAs derived from the tra and Sxl mRNA precursors with guanosine and adenosine, respectively, in a position near the 5'-terminus of a uridine stretch. First, we prepared a [5- 2 H]uridine phosphoramidite, and synthesized a series of 2 H-labeled RNAs, in which all of the uridine residues except one were replaced by [5- 2 H]uridine in the target sequence, GU 8 C. By observing the H5-H6 TOCSY cross peaks of the series of 2 H-labeled RNAs complexed with the Sxl RBD1-RBD2, all of the base H5-H6 proton resonances of the target RNA were unambiguously assigned. Then, the H5-H6 cross peaks of other target RNAs, GU 2 GU 8 , AU 8 , and UAU 8 , were assigned by comparison with those of GU 8 C. We found that the uridine residue prior to the G or A residue is essential for proper interaction with the protein, and that the interaction is tighter for A than for G. Moreover, the H1' resonance assignments were achieved from the H5-H6 assignments. The results revealed that all of the protein-bound nucleotide residues, except for only two, are in the unusual C2'-endo ribose conformation in the complex

  18. Interactions of a didomain fragment of the Drosophila Sex-lethal protein with single-stranded uridine-rich oligoribonucleotides derived from the transformer and Sex-lethal messenger RNA precursors: NMR with residue-selective [5-2H]uridine substitutions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Insil; Muto, Yutaka; Watanabe, Satoru; Kitamura, Aya; Futamura, Yasuhiro; Yokoyama, Shigeyuki [University of Tokyo, Department of Biophysics and Biochemistry, Graduate School of Science (Japan); Hosono, Kazumi; Kawai, Gota; Takaku, Hiroshi [Chiba Institute of Technology, Department of Industrial Chemistry (Japan); Dohmae, Naoshi; Takio, Koji [Institute of Physical and Chemical Research (RIKEN) (Japan); Sakamoto, Hiroshi [Kobe University, Department of Biology, Faculty of Science (Japan); Shimura, Yoshiro [Biomolecular Engineering Research Institute (Japan)

    2000-06-15

    Proteins that contain two or more copies of the RNA-binding domain [ribonucleoprotein (RNP) domain or RNA recognition motif (RRM)] are considered to be involved in the recognition of single-stranded RNA, but the mechanisms of this recognition are poorly understood at the molecular level. For an NMR analysis of a single-stranded RNA complexed with a multi-RBD protein, residue-selective stable-isotope labeling techniques are necessary, rather than common assignment methods based on the secondary structure of RNA. In the present study, we analyzed the interaction of a Drosophila Sex-lethal (Sxl) protein fragment, consisting of two RBDs (RBD1-RBD2), with two distinct target RNAs derived from the tra and Sxl mRNA precursors with guanosine and adenosine, respectively, in a position near the 5'-terminus of a uridine stretch. First, we prepared a [5-{sup 2}H]uridine phosphoramidite, and synthesized a series of {sup 2}H-labeled RNAs, in which all of the uridine residues except one were replaced by [5-{sup 2}H]uridine in the target sequence, GU{sub 8}C. By observing the H5-H6 TOCSY cross peaks of the series of {sup 2}H-labeled RNAs complexed with the Sxl RBD1-RBD2, all of the base H5-H6 proton resonances of the target RNA were unambiguously assigned. Then, the H5-H6 cross peaks of other target RNAs, GU{sub 2}GU{sub 8}, AU{sub 8}, and UAU{sub 8}, were assigned by comparison with those of GU{sub 8}C. We found that the uridine residue prior to the G or A residue is essential for proper interaction with the protein, and that the interaction is tighter for A than for G. Moreover, the H1' resonance assignments were achieved from the H5-H6 assignments. The results revealed that all of the protein-bound nucleotide residues, except for only two, are in the unusual C2'-endo ribose conformation in the complex.

  19. Management of NORM Residues

    International Nuclear Information System (INIS)

    2013-06-01

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  20. Neuroendocrine and Immune Responses Undertake Different Fates following Tryptophan or Methionine Dietary Treatment: Tales from a Teleost Model

    Directory of Open Access Journals (Sweden)

    Rita Azeredo

    2017-09-01

    Full Text Available Methionine and tryptophan appear to be fundamental in specific cellular pathways involved in the immune response mechanisms, including stimulation of T-regulatory cells by tryptophan metabolites or pro-inflammatory effects upon methionine supplementation. Thus, the aim of this study was to evaluate the immunomodulatory effect of these amino acids on the inflammatory and neuroendocrine responses in juveniles of European seabass, Dicentrarchus labrax. To achieve this, goal fish were fed for 14 days methionine and tryptophan-supplemented diets (MET and TRP, respectively, 2× dietary requirement level or a control diet meeting the amino acids requirement levels (CTRL. Fish were sampled for immune status assessment and the remaining fish were challenged with intraperitoneally injected inactivated Photobacterium damselae subsp. piscicida and sampled either 4 or 24 h post-injection. Respiratory burst activity, brain monoamines, plasma cortisol, and immune-related gene expression showed distinct and sometimes opposite patterns regarding the effects of dietary amino acids. While neuroendocrine intermediates were not affected by any dietary treatment at the end of the feeding trial, both supplemented diets led to increased levels of plasma cortisol after the inflammatory insult, while brain monoamine content was higher in TRP-fed fish. Peripheral blood respiratory burst was higher in TRP-fed fish injected with the bacteria inoculum but only compared to those fed MET. However, no changes were detected in total antioxidant capacity. Complement factor 3 was upregulated in MET-fed fish but methionine seemed to poorly affect other genes expression patterns. In contrast, fish fed MET showed increased immune cells numbers both before and after immune challenge, suggesting a strong enhancing effect of methionine on immune cells proliferation. Differently, tryptophan effects on inflammatory transcripts suggested an inhibitory mode of action. This, together

  1. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A N; Webster, G A [Imperial College, London (United Kingdom); Webster, P J [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  2. NMR assignments for the amino-terminal residues of trp repressor and their role in DNA binding

    International Nuclear Information System (INIS)

    Arrowsmith, C.H.; Carey, J.; Treat-Clemons, L.; Jardetzky, O.

    1989-01-01

    The trp repressor of Escherichia coli specifically binds to operator DNAs in three operons involved in tryptophan metabolism. The NMR spectra of repressor and a chymotryptic fragment lacking the six amino-terminal residues are compared. Two-dimensional J-correlated spectra of the two forms of the protein are superimposable except for cross-peaks that are associated with the N-terminal region. The chemical shifts and relaxation behavior of the N-terminal resonances suggest mobile arms. Spin-echo experiments on a ternary complex of repressor with L-tryptophan and operator DNA indicate that the termini are also disordered in the complex, although removal of the arms reduces the DNA binding energy. Relaxation measurements on the armless protein show increased mobility for several residues, probably due to helix fraying in the newly exposed N-terminal region. DNA binding by the armless protein does not reduce the mobility of these residues. Thus, it appears that the arms serve to stabilize the N-terminal helix but that this structural role does not explain their contribution to the DNA binding energy. These results suggest that the promiscuous DNA binding by the arms seen in the X-ray crystal structure is found in solution as well

  3. The association between the hypothalamic pituitary adrenal axis and tryptophan metabolism in persons with recurrent major depressive disorder and healthy controls

    NARCIS (Netherlands)

    Sorgdrager, F. J. H.; Doornbos, B.; Penninx, B. W. J. H.; de Jonge, P.; Kema, I. P.

    2017-01-01

    Objectives: Persistent changes in serotonergic and hypothalamic pituitary adrenal (HPA) axis functioning are implicated in recurrent types of major depressive disorder (MDD). Systemic tryptophan levels, which influence the rate of serotonin synthesis, are regulated by glucocorticoids produced along

  4. Metabolism of /sup 14/C-labelled L-tryptophan, L-kynurenine, and hydroxy-L-kynurenine in miners with scleroderma

    Energy Technology Data Exchange (ETDEWEB)

    Hankes, L.V.; De Bruin, E.; Jansen, C.R.; Vorster, L.; Schmaeler, M.

    1977-03-19

    Six South African white miners were studied with the 2-g L-tryptophan load test and tracer doses of L-tryptophan-7a-/sup 14/C, L-kynurenine-keto-/sup 14/C and hydroxy-L-kynurenine-keto-/sup 14/C. The breath /sup 14/CO/sub 2/ and 14 urinary metabolites were measured. When they were compared with a previous study of American women with scleroderma, similar /sup 14/CO/sub 2/ and tryptophan metabolite excretion patterns were observed in the data from the miners. The labelled quinolinic acid excretion was more significantly elevated in the South African miners' urine than in the urine of the American women. The data from both studies suggest that some patients with scleroderma have an altered step in the tryptophan metabolic pathway after hydroxy-anthranilic acid. What relationship exists between the induction of pulmonary silicosis and the subsequent development of scleroderma, requires additional human studies.

  5. Designing with residual materials

    NARCIS (Netherlands)

    Walhout, W.; Wever, R.; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies

  6. Internalisation of the mu-opioid receptor by endomorphin-1 and leu-enkephalin is dependant on aromatic amino acid residues.

    Science.gov (United States)

    Del Borgo, Mark P; Blanchfield, Joanne T; Toth, Istvan

    2008-04-15

    The opioid receptor system in the central nervous system controls a number of physiological processes, most notably pain. However, most opioids currently available have a variety of side-effects as well as exhibiting tolerance. Tolerance is most likely to be a complex phenomenon, however, the role of receptor internalisation is thought to play a crucial role. In this study, we examined the role of aromaticity in ligand-mediated receptor internalisation of the mu-opioid receptor (MOPR). These studies show that the amount of receptor internalisation may be dependant on the amphiphilicity of the ligand. Specifically, deletion of the C-terminus aromatic residues of endomorphin 1, particularly tryptophan reduces receptor-mediated internalisation whilst the addition of tryptophan within the enkephalin sequence increases receptor internalisation and decreases tolerance.

  7. Study on the interaction of tropisetron hydrochloride and L-tryptophan by spectrofluorimetry and its analytical application

    International Nuclear Information System (INIS)

    Zhu Xiashi; Gong Aiqin; Wang Baosheng; Yu Suhai

    2008-01-01

    A new method to determine tropisetron hydrochloride with L-tryptophan in the medium with pH=9.0 was studied, which is based on the fluorescence quenching effect of tropisetron hydrochloride on L-tryptophan. The fluorescence quenching mechanism and various factors influencing fluorescence quenching were discussed. Under the optimum conditions, the linear range and detection limit were 0.03-12.0 and 0.01 μg/mL (correlation coefficient r=0.9970), respectively. The calibration curve equation was ΔF=6.17+12.56 C (μg/mL). RSD was 3.4% (c=4.0 μg/mL, n=5); the detection limit estimated (S/N=3) was 0.01 μg/mL. The proposed method had been successfully applied to determine tropisetron hydrochloride in real samples and the obtained results were in good agreement with the results of the official method

  8. Computational Protocols for Prediction of Solute NMR Relative Chemical Shifts. A Case Study of L-Tryptophan in Aqueous Solution

    DEFF Research Database (Denmark)

    Eriksen, Janus J.; Olsen, Jógvan Magnus H.; Aidas, Kestutis

    2011-01-01

    to the results stemming from the conformations extracted from the MM conformational search in terms of replicating an experimental reference as well as in achieving the correct sequence of the NMR relative chemical shifts of L-tryptophan in aqueous solution. We find this to be due to missing conformations......In this study, we have applied two different spanning protocols for obtaining the molecular conformations of L-tryptophan in aqueous solution, namely a molecular dynamics simulation and a molecular mechanics conformational search with subsequent geometry re-optimization of the stable conformers...... using a quantum mechanically based method. These spanning protocols represent standard ways of obtaining a set of conformations on which NMR calculations may be performed. The results stemming from the solute–solvent configurations extracted from the MD simulation at 300 K are found to be inferior...

  9. Real-time detection of faecally contaminated drinking water with tryptophan-like fluorescence: defining threshold values.

    Science.gov (United States)

    Sorensen, James P R; Baker, Andy; Cumberland, Susan A; Lapworth, Dan J; MacDonald, Alan M; Pedley, Steve; Taylor, Richard G; Ward, Jade S T

    2018-05-01

    We assess the use of fluorescent dissolved organic matter at excitation-emission wavelengths of 280nm and 360nm, termed tryptophan-like fluorescence (TLF), as an indicator of faecally contaminated drinking water. A significant logistic regression model was developed using TLF as a predictor of thermotolerant coliforms (TTCs) using data from groundwater- and surface water-derived drinking water sources in India, Malawi, South Africa and Zambia. A TLF threshold of 1.3ppb dissolved tryptophan was selected to classify TTC contamination. Validation of the TLF threshold indicated a false-negative error rate of 15% and a false-positive error rate of 18%. The threshold was unsuccessful at classifying contaminated sources containing water globally. Copyright © 2017 Natural Environment Research Council (NERC), as represented by the British Geological Survey (BGS. Published by Elsevier B.V. All rights reserved.

  10. Remarkable Role of Indoleamine 2,3-Dioxygenase and Tryptophan Metabolites in Infectious Diseases: Potential Role in Macrophage-Mediated Inflammatory Diseases

    OpenAIRE

    Murakami, Yuki; Hoshi, Masato; Imamura, Yukio; Arioka, Yuko; Yamamoto, Yasuko; Saito, Kuniaki

    2013-01-01

    Indoleamine 2,3-dioxygenase 1 (IDO1), the L-tryptophan-degrading enzyme, plays a key role in the immunomodulatory effects on several types of immune cells. Originally known for its regulatory function during pregnancy and chronic inflammation in tumorigenesis, the activity of IDO1 seems to modify the inflammatory state of infectious diseases. The pathophysiologic activity of L-tryptophan metabolites, kynurenines, is well recognized. Therefore, an understanding of the regulation of IDO1 and th...

  11. Tryptophan Intake in the US Adult Population Is Not Related to Liver or Kidney Function but Is Associated with Depression and Sleep Outcomes.

    Science.gov (United States)

    Lieberman, Harris R; Agarwal, Sanjiv; Fulgoni, Victor L

    2016-12-01

    Tryptophan is an indispensable amino acid and is a precursor of the neurotransmitter serotonin. Tryptophan metabolites, such as serotonin and melatonin, are thought to participate in the regulation of mood and sleep and tryptophan is used to treat insomnia, sleep apnea, and depression. This study examined the intake of tryptophan and its associations with biochemical, behavioral, sleep, and health and safety outcomes in adults in a secondary analysis of a large, publicly available database of the US population. Data from the NHANES 2001-2012 (n = 29,687) were used to determine daily intakes of tryptophan and its associations with biochemical markers of health- and safety-related outcomes, self-reported depression, and sleep-related variables. Data were adjusted for demographic factors and protein intake. Linear trends were computed across deciles of intake for each outcome variable, and P-trends were determined. The usual tryptophan intake by US adults was 826 mg/d, severalfold higher than the Estimated Average Requirement for adults of 4 mg/(kg ⋅ d) (∼280 mg/d for a 70-kg adult). Most health- and safety-related biochemical markers of liver function, kidney function, and carbohydrate metabolism were not significantly (P-trend > 0.05) associated with deciles of tryptophan intake and were well within normal ranges, even for individuals in the 99th percentile of intake. Usual intake deciles of tryptophan were inversely associated with self-reported depression measured by the Patient Health Questionnaire raw score (0-27; P-trend depression, 5 = severe depression; P-trend depression and positively associated with sleep duration. © 2016 American Society for Nutrition.

  12. Role of Hydrophobic/Aromatic Residues on the Stability of Double-Wall β-Sheet Structures Formed by a Triblock Peptide.

    Science.gov (United States)

    Ozgur, Beytullah; Sayar, Mehmet

    2017-04-27

    Bioinspired self-assembling peptides serve as powerful building blocks in the manufacturing of nanomaterials with tailored features. Because of their ease of synthesis, biocompatibility, and tunable activity, this emerging branch of biomolecules has become very popular. The triblock peptide architecture designed by the Hartgerink group is a versatile system that allows control over its assembly and has been shown to demonstrate tunable bioactivity. Three main forces, Coulomb repulsion, hydrogen bonding and hydrophobicity act together to guide the triblock peptides' assembly into one-dimensional objects and hydrogels. It was shown previously that both the nanofiber morphology (e.g., intersheet spacing, formation of antiparallel/parallel β-sheets) and hydrogel rheology strictly depend on the choice of the core residue where the triblock peptide fibers with aromatic cores in general form shorter fibers and yield poor hydrogels with respect to the ones with aliphatic cores. However, an elaborate understanding of the molecular reasons behind these changes remained unclear. In this study, by using carefully designed computer based free energy calculations, we analyzed the influence of the core residue on the formation of double-wall fibers and single-wall β-sheets. Our results demonstrate that the aromatic substitution impairs the fiber cores and this impairment is mainly associated with a reduced hydrophobic character of the aromatic side chains. Such weakening is most obvious in tryptophan containing peptides where the fiber core absorbs a significant amount of water. We also show that the ability of tyrosine to form side chain hydrogen bonds plays an indispensable role in the fiber stability. As opposed to the impairment of the fiber cores, single-wall β-sheets with aromatic faces become more stable compared to the ones with aliphatic faces suggesting that the choice of the core residue can also affect the underlying assembly mechanism. We also provide an in

  13. Effects of acute tryptophan depletion on central processing of CT-targeted and discriminatory touch in humans.

    Science.gov (United States)

    Trotter, Paula Diane; McGlone, Francis; McKie, Shane; McFarquhar, Martyn; Elliott, Rebecca; Walker, Susannah Claire; Deakin, John Francis William

    2016-08-01

    C-tactile afferents (CTs) are slowly conducting nerve fibres, present only in hairy skin. They are optimally activated by slow, gentle stroking touch, such as those experienced during a caress. CT stimulation activates affective processing brain regions, alluding to their role in affective touch perception. We tested a theory that CT-activating touch engages the pro-social functions of serotonin, by determining whether reducing serotonin, through acute tryptophan depletion, diminishes subjective pleasantness and affective brain responses to gentle touch. A tryptophan depleting amino acid drink was administered to 16 healthy females, with a further 14 receiving a control drink. After 4 h, participants underwent an fMRI scan, during which time CT-innervated forearm skin and CT non-innervated finger skin was stroked with three brushes of differing texture, at CT-optimal force and velocity. Pleasantness ratings were obtained post scanning. The control group showed a greater response in ipsilateral orbitofrontal cortex to CT-activating forearm touch compared to touch to the finger where CTs are absent. This differential response was not present in the tryptophan depleted group. This interaction effect was significant. In addition, control participants showed a differential primary somatosensory cortex response to brush texture applied to the finger, a purely discriminatory touch response, which was not observed in the tryptophan depleted group. This interaction effect was also significant. Pleasantness ratings were similar across treatment groups. These results implicate serotonin in the differentiation between CT-activating and purely discriminatory touch responses. Such effects could contribute to some of the social abnormalities seen in psychiatric disorders associated with abnormal serotonin function. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  14. High tryptophan diet reduces CA1 intraneuronal ss-amyloid in the triple transgenic mouse model of Alzheimer's disease.

    Czech Academy of Sciences Publication Activity Database

    Noristani, H. N.; Verkhratsky, A.; Rodríguez Arellano, Jose Julio

    2012-01-01

    Roč. 11, č. 5 (2012), s. 810-822 ISSN 1474-9718 R&D Projects: GA ČR GA309/09/1696; GA ČR GA305/08/1384; GA ČR(CZ) GAP304/11/0184 Institutional research plan: CEZ:AV0Z50390703 Institutional support: RVO:68378041 Keywords : Alzheimer's disease * hippocampus * L-tryptophan diet Subject RIV: FH - Neurology Impact factor: 5.705, year: 2012

  15. The short (S) allele of the serotonin transporter polymorphism and acute tryptophan depletion both increase impulsivity in men

    OpenAIRE

    Walderhaug, Espen; Herman, Aryeh Isaac; Magnusson, Andres; Morgan, Michael John; Landrø, Nils Inge

    2010-01-01

    Reduced serotonergic neurotransmission is implicated in impulsive behavior. We studied the triallelic system of the serotonin transporter gene linked polymorphic region (5-HTTLPR) and acute manipulation of serotonin together to further delineate the mechanisms by which serotonergic neurotransmission affects impulsivity. Fifty-two healthy participants (38 men and 14 women) underwent acute tryptophan depletion (ATD) or placebo in a randomized, double-blind, parallel group experiment. Impulsive ...

  16. Mutations in Cancer Cause Gain of Cysteine, Histidine, and Tryptophan at the Expense of a Net Loss of Arginine on the Proteome Level

    Directory of Open Access Journals (Sweden)

    Viktoriia Tsuber

    2017-07-01

    Full Text Available Accumulation of somatic mutations is critical for the transition of a normal cell to become cancerous. Mutations cause amino acid substitutions that change properties of proteins. However, it has not been studied as to what extent the composition and accordingly chemical properties of the cell proteome is altered as a result of the increased mutation load in cancer. Here, we analyzed data on amino acid substitutions caused by mutations in about 2000 protein coding genes from the Cancer Cell Line Encyclopedia that contains information on nucleotide and amino acid alterations in 782 cancer cell lines, and validated the analysis with information on amino acid substitutions for the same set of proteins in the Catalogue of Somatic Mutations in Cancer (COSMIC; v78 in circa 18,000 tumor samples. We found that nonsynonymous single nucleotide substitutions in the analyzed proteome subset ultimately result in a net gain of cysteine, histidine, and tryptophan at the expense of a net loss of arginine. The extraordinary loss of arginine may be attributed to some extent to composition of its codons as well as to the importance of arginine in the functioning of prominent tumor suppressor proteins like p53.

  17. An artificial self-sufficient cytochrome P450 directly nitrates fluorinated tryptophan analogs with a different regio-selectivity.

    Science.gov (United States)

    Zuo, Ran; Zhang, Yi; Huguet-Tapia, Jose C; Mehta, Mishal; Dedic, Evelina; Bruner, Steven D; Loria, Rosemary; Ding, Yousong

    2016-05-01

    Aromatic nitration is an immensely important industrial process to produce chemicals for a variety of applications, but it often suffers from multiple unsolved challenges. Enzymes as biocatalysts have been increasingly used for organic chemistry synthesis due to their high selectivity and environmental friendliness, but nitration has benefited minimally from the development of biocatalysis. In this work, we aimed to develop TxtE as practical biocatalysts for aromatic nitration. TxtE is a unique class I cytochrome P450 enzyme that nitrates the indole of l-tryptophan. To develop cost-efficient nitration processes, we fused TxtE with the reductase domains of CYP102A1 (P450BM3) and of P450RhF to create class III self-sufficient biocatalysts. The best engineered fusion protein was comparable with wild type TxtE in terms of nitration performance and other key biochemical properties. To demonstrate the application potential of the fusion enzyme, we nitrated 4-F-dl-tryptophan and 5-F-l-tryptophan in large scale enzymatic reactions. Tandem MS/MS and NMR analyses of isolated products revealed altered nitration sites. To our knowledge, these studies represent the first practice in developing biological nitration approaches and lay a solid basis to the use of TxtE-based biocatalysts for the production of valuable nitroaromatics. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Preparation and HPLC isolation of L-[U-14C]tryptophan from enzyme hydrolysate labelled with 14C

    International Nuclear Information System (INIS)

    Novak, J.; Tintera, S.; Hromadkova, B.

    1990-01-01

    Tryptophan was obtained from biomass of the blue-green alga Synechococcus elongatus cultivated under 14 CO 2 . After partial purification, the protein fraction was subjected to enzymatic hydrolysis using pronase. Semipreparative isolation of L-[U- 14 C]tryptophan was accomplished on a HPLC column of Separon S Hema 1000 CM, 2% ethanol were added to the eluent, and a precolumn packed with the basic anion exchanger Spheron 1000 DEAE was used. Always after the passage of L-[U- 14 C]tryptophan, the precolumn was decoupled. The substance was collected in 96% ethanol. After removing the solvent by vacuum evaporation, the sample was analyzed on a column packed with Separon SIX C 18 in the eluent of 0.1M-NaH 2 PO 4 , 2% methanol. When the desired radiochemical purity was not attained, the sample was purified on Separon SIX C 18 using 2% methanol. The final radiochemical purity achieved by using this method is 98%. (P.A.). 5 figs., 2 tabs., 4 refs

  19. Membrane interaction and secondary structure of de novo designed arginine-and tryptophan peptides with dual function

    KAUST Repository

    Rydberg, Hanna A.

    2012-10-01

    Cell-penetrating peptides and antimicrobial peptides are two classes of positively charged membrane active peptides with several properties in common. The challenge is to combine knowledge about the membrane interaction mechanisms and structural properties of the two classes to design peptides with membrane-specific actions, useful either as transporters of cargo or as antibacterial substances. Membrane active peptides are commonly rich in arginine and tryptophan. We have previously designed a series of arg/trp peptides and investigated how the position and number of tryptophans affect cellular uptake. Here we explore the antimicrobial properties and the interaction with lipid model membranes of these peptides, using minimal inhibitory concentrations assay (MIC), circular dichroism (CD) and linear dichroism (LD). The results show that the arg/trp peptides inhibit the growth of the two gram positive strains Staphylococcus aureus and Staphylococcus pyogenes, with some individual variations depending on the position of the tryptophans. No inhibition of the gram negative strains Proteus mirabilis or Pseudomonas aeruginosa was noticed. CD indicated that when bound to lipid vesicles one of the peptides forms an α-helical like structure, whereas the other five exhibited rather random coiled structures. LD indicated that all six peptides were somehow aligned parallel with the membrane surface. Our results do not reveal any obvious connection between membrane interaction and antimicrobial effect for the studied peptides. By contrast cell-penetrating properties can be coupled to both the secondary structure and the degree of order of the peptides. © 2012 Elsevier Inc.

  20. Composite system based on biomolecules-functionalized multiwalled carbon nanotube and ionic liquid: Electrochemistry and electrocatalysis of tryptophane

    International Nuclear Information System (INIS)

    Li Li; Bu Caihong; Zhang Yijun; Du Jie; Lu Xiaoquan; Liu Xiuhui

    2011-01-01

    The combination of biomolecules-functionalized multiwalled carbon nanotube (MWNTs) and ionic liquid (IL) yields nanostructured biointerfaces, formed a novel kind of structurally uniform and bioelectrocatalytic activity material. Rutin was chosen as a model biomolecules to investigate the composite system. The MWNTs–Rutin–IL composite film was characterized by different methods including thermogravimetric analysis (TGA), UV–vis spectra, electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscope (SECM). A pair of well-defined quasi reversible redox peaks of rutin was obtained at the MWNTs–Rutin–IL composite film modified glassy carbon electrode (GCE) by direct electron transfer between the rutin and the GCE electrode. Dramatically enhanced biocatalytic and electrocatalytic activity was exemplified at the MWNTs–Rutin–IL/GCE electrode by the oxidized of tryptophane. The oxidation peak currents of tryptophane in such modified electrode increased linearly with the concentrations of tryptophane in the range from 8 × 10 −8 to 2 × 10 −5 mol L −1 with a detection limit of 3.0 × 10 −8 mol L −1 . The unique composite material based on biomolecules-functionalized carbon nanotube and ionic liquid have wide potential applications in direct electrochemistry, biosensors, and biocatalysis.

  1. Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis

    Science.gov (United States)

    Jenkins, Trisha A.; Nguyen, Jason C. D.; Polglaze, Kate E.; Bertrand, Paul P.

    2016-01-01

    The serotonergic system forms a diffuse network within the central nervous system and plays a significant role in the regulation of mood and cognition. Manipulation of tryptophan levels, acutely or chronically, by depletion or supplementation, is an experimental procedure for modifying peripheral and central serotonin levels. These studies have allowed us to establish the role of serotonin in higher order brain function in both preclinical and clinical situations and have precipitated the finding that low brain serotonin levels are associated with poor memory and depressed mood. The gut-brain axis is a bi-directional system between the brain and gastrointestinal tract, linking emotional and cognitive centres of the brain with peripheral functioning of the digestive tract. An influence of gut microbiota on behaviour is becoming increasingly evident, as is the extension to tryptophan and serotonin, producing a possibility that alterations in the gut may be important in the pathophysiology of human central nervous system disorders. In this review we will discuss the effect of manipulating tryptophan on mood and cognition, and discuss a possible influence of the gut-brain axis. PMID:26805875

  2. On the efficient bio-incorporation of 5-hydroxy-tryptophan in recombinant proteins expressed in Escherichia coli with T7 RNA polymerase-based vectors.

    Science.gov (United States)

    Oliveira-Souza, Wellington P; Bronze, Fellipe; Broos, Jaap; Marcondes, Marcelo F M; Oliveira, Vitor

    2017-10-21

    Biosynthetic incorporation of non-canonic amino acids is an attractive strategy to introduce new properties in recombinant proteins. Trp analogs can be incorporated in recombinant proteins replacing regular Trp during protein translation into a Trp-auxotrophic cell host. This straightforward method however, is limited to few analogs recognized and accepted by the cellular protein production machinery. 5-hydroxy-tryptophan (5OH-Trp) can be bio-incorporated using E. coli as expression host however; we have experienced very low incorporation yields - amount of protein containing regular Trp/amount of protein containing the Trp analog - during expressions of 5OH-Trp labeled proteins. Furthermore, this low incorporation yield were verified especially when the widely-used vectors based on the T7 RNA polymerase were used. Testing different 5OH-Trp incorporation protocols we verified that in these T7-based systems, the production of the T7 RNA polymerase is driven by the same elements - lac promoter/IPTG - as the target protein. Consequently, the bio-incorporation of the 5OH-Trp residues also occurs in this crucial enzyme, but, the produced T7 RNA polymerase labeled with 5OH-Trp is inactive or much less active. In the present work, we describe an efficient method to overcome this mentioned problem and bio-incorporate 5OH-Trp in proteins expressed in E. coli., using vectors based on the T7 RNA polymerase-T7 promoter. The two-step induction protocol here described showed incorporation efficiencies of 5OH-Trp higher than 90%. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Two-channel dansyl/tryptophan emitters with a cholic acid bridge as reporters for local hydrophobicity within supramolecular systems based on bile salts.

    Science.gov (United States)

    Gomez-Mendoza, M; Marin, M Luisa; Miranda, Miguel A

    2014-11-14

    The aim of the present work is to develop two-channel emitters to probe local hydrophobicity by means of fluorescence quenching within different biomimetic supramolecular environments. To achieve this goal, the dansyl (Dns) and tryptophan (Trp) fluorophores have been covalently attached to cholic acid (CA) in order to ensure simultaneous incorporation of the two emitting units into the same compartment. In principle, the two fluorophores of the synthesized Dns-CA-Trp probes could either exhibit an orthogonal behavior or display excited state interactions. The fluorescence spectra of 3β-Dns-CA-Trp showed a residual Trp emission band at ca. 350 nm and an enhanced Dns maximum in the 500-550 nm region. This reveals a partial intramolecular energy transfer, which is consistent with the Dns and Trp singlet energies. Thus, the two photoactive units are not orthogonal; nevertheless, 3β-Dns-CA-Trp seems appropriate as a two-channel reporter for the supramolecular systems of interest. Fluorescence quenching of 3β-Dns-CA-Trp by iodide (which remains essentially in bulk water) was examined within sodium cholate, sodium taurocholate, sodium deoxycholate and mixed micelles. Interestingly, a decrease in the emission intensity of the two bands was observed with increasing iodide concentrations. The most remarkable effect was observed for mixed micelles, where the quenching rate constants were one order of magnitude lower than in solution. As anticipated, the quenching efficiency by iodide decreased with increasing hydrophobicity of the microenvironment, a trend that can be correlated with the relative accessibility of the probe to the ionic quencher.

  4. Application of gene targeting to designed mutation breeding of high-tryptophan rice.

    Science.gov (United States)

    Saika, Hiroaki; Oikawa, Akira; Matsuda, Fumio; Onodera, Haruko; Saito, Kazuki; Toki, Seiichi

    2011-07-01

    Site-directed mutagenesis via gene targeting (GT) based on homologous recombination is the ultimate mutation breeding technology because it enables useful information acquired from structural- and computational-based protein engineering to be applied directly to molecular breeding, including metabolic engineering, of crops. Here, we employed this rationale to introduce precise mutations in OASA2--an α-subunit of anthranilate synthase that is a key enzyme of tryptophan (Trp) biosynthesis in rice (Oryza sativa)--via GT, with subsequent selection of GT cells using a Trp analog. The expression level of OASA2 in plants homozygous and heterozygous for modified OASA2 was similar to that of nontransformants, suggesting that OASA2 transcription in GT plants was controlled in the same manner as endogenous OASA2, and that GT could lead to a lower risk of gene silencing than in conventional overexpression approaches. Moreover, we showed that enzymatic properties deduced from protein engineering or in vitro analysis could be reproduced in GT plants as evidenced by Trp accumulation levels. Interestingly, mature seeds of homozygous GT plants accumulated Trp levels 230-fold higher than in nontransformants without any apparent morphological or developmental changes. Thus, we have succeeded in producing a novel rice plant of great potential nutritional benefit for both man and livestock that could not have been selected using conventional mutagenesis approaches. Our results demonstrate the effectiveness of directed crop improvement by combining precision mutagenesis via GT with a knowledge of protein engineering.

  5. 5-HT modulation by acute tryptophan depletion of human instrumental contingency judgements.

    Science.gov (United States)

    Chase, Henry W; Crockett, Molly J; Msetfi, Rachel M; Murphy, Robin A; Clark, Luke; Sahakian, Barbara J; Robbins, Trevor W

    2011-02-01

    The concept of 'depressive realism', that depression leads to more accurate perception of causal control, has been influential in the field of depression research, but remains controversial. Recent work testing contingency learning has suggested that contextual processing might determine realism-like effects. Serotonin (5-hydroxytryptamine, (5-HT)), which is implicated in the pathophysiology of depression, might also influence contextual processing. Using acute tryptophan depletion (ATD), we tested the hypothesis that dysfunctional serotoninergic neurotransmission influences contingency judgements in dysphoric subjects via an effect on contextual processing. We employed a novel contingency learning task to obtain separate measures (ratings) of the causal effect of participants' responses and efficacy of the background context over an outcome. Participants, without a history of depression, completed this task on and off ATD in a double-blind, placebo-controlled, within-subjects design. As with other work on contingency learning, the effects of ATD were related to baseline mood levels. Although no overall effects of ATD were observed, the subgroup of participants with low Beck depression inventory (BDI) scores showed reduced ratings of contextual control and improved accuracy of contingency judgements under positive contingencies following ATD, compared to placebo. High BDI participants demonstrated low accuracy in contingency judgements, regardless of serotoninergic status. No effect of ATD on contingency judgements was observed in the group as a whole, but effects were observed in a subgroup of participants with low BDI scores. We discuss these data in light of the context processing hypothesis, and prior research on 5-HT and depressive realism.

  6. Effect of Tryptophan Hydroxylase-2 rs7305115 SNP on suicide attempts risk in major depression

    Directory of Open Access Journals (Sweden)

    Zhang Yuqi

    2010-08-01

    Full Text Available Abstract Background Suicide and major depressive disorders (MDD are strongly associated, and genetic factors are responsible for at least part of the variability in suicide risk. We investigated whether variation at the tryptophan hydroxylase-2 (TPH2 gene rs7305115 SNP may predispose to suicide attempts in MDD. Methods We genotyped TPH2 gene rs7305115 SNP in 215 MDD patients with suicide and matched MDD patients without suicide. Differences in behavioral and personality traits according to genotypic variation were investigated by logistic regression analysis. Results There were no significant differences between MDD patients with suicide and controls in genotypic (AG and GG frequencies for rs7305115 SNP, but the distribution of AA genotype differed significantly (14.4% vs. 29.3%, p p p Conclusions The study suggested that hopelessness, negative life events and family history of suicide were risk factors of attempted suicide in MDD while the TPH2 rs7305115A remained a significant protective predictor of suicide attempts.

  7. Interactions between the nuclear matrix and an enhancer of the tryptophan oxygenase gene

    Energy Technology Data Exchange (ETDEWEB)

    Kaneoka, Hidenori [Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Miyake, Katsuhide, E-mail: miyake@nubio.nagoya-u.ac.jp [Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Iijima, Shinji [Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2009-10-02

    The gene for tryptophan oxygenase (TO) is expressed in adult hepatocytes in a tissue- and differentiation-specific manner. The TO promoter has two glucocorticoid-responsive elements (GREs), and its expression is regulated by glucocorticoid hormone in the liver. We found a novel GRE in close proximity to a scaffold/matrix attachment region (S/MAR) that was located around -8.5 kb from the transcriptional start site of the TO gene by electrophoretic mobility shift and chromatin immunoprecipitation (ChIP) assays. A combination of nuclear fractionation and quantitative PCR analysis showed that the S/MAR was tethered to the nuclear matrix in both fetal and adult hepatocytes. ChIP assay showed that, in adult hepatocytes, the S/MAR-GRE and the promoter proximal regions interacted with lamin and heterogeneous nuclear ribonucleoprotein U in a dexamethasone dependent manner, but this was not the case in fetal cells, suggesting that developmental stage-specific expression of the TO gene might rely on the binding of the enhancer (the -8.5 kb S/MAR-GRE) and the promoter to the inner nuclear matrix.

  8. Alterations in tryptophan and purine metabolism in cocaine addiction: a metabolomic study.

    Science.gov (United States)

    Patkar, Ashwin A; Rozen, Steve; Mannelli, Paolo; Matson, Wayne; Pae, Chi-Un; Krishnan, K Ranga; Kaddurah-Daouk, Rima

    2009-10-01

    Mapping metabolic "signatures" can provide new insights into addictive mechanisms and potentially identify biomarkers and therapeutic targets. We examined the differences in metabolites related to the tyrosine, tryptophan, purine, and oxidative stress pathways between cocaine-dependent subjects and healthy controls. Several of these metabolites serve as biological indices underlying the mechanisms of reinforcement, toxicity, and oxidative stress. Metabolomic analysis was performed in 18 DSM-IV-diagnosed cocaine-dependent individuals with at least 2 weeks of abstinence and ten drug-free controls. Plasma concentrations of 37 known metabolites were analyzed and compared using a liquid chromatography electrochemical array platform. Multivariate analyses were used to study the relationship between severity of drug use [Addiction Severity Index (ASI) scores] and biological measures. Cocaine subjects showed significantly higher levels of n-methylserotonin (p cocaine and control groups with no overlap. Alterations in the methylation processes in the serotonin pathways and purine metabolism seem to be associated with chronic exposure to cocaine. Given the preliminary nature and cross-sectional design of the study, the findings need to be confirmed in larger samples of cocaine-dependent subjects, preferably in a longitudinal design.

  9. Tryptophan hydroxylase Is Required for Eye Melanogenesis in the Planarian Schmidtea mediterranea.

    Directory of Open Access Journals (Sweden)

    Bramwell G Lambrus

    Full Text Available Melanins are ubiquitous and biologically important pigments, yet the molecular mechanisms that regulate their synthesis and biochemical composition are not fully understood. Here we present a study that supports a role for serotonin in melanin synthesis in the planarian Schmidtea mediterranea. We characterize the tryptophan hydroxylase (tph gene, which encodes the rate-limiting enzyme in serotonin synthesis, and demonstrate by RNA interference that tph is essential for melanin production in the pigment cups of the planarian photoreceptors. We exploit this phenotype to investigate the biological function of pigment cups using a quantitative light-avoidance behavioral assay. Planarians lacking eye pigment remain phototactic, indicating that eye pigmentation is not essential for light avoidance in S. mediterranea, though it improves the efficiency of the photophobic response. Finally, we show that the eye pigmentation defect observed in tph knockdown animals can be rescued by injection of either the product of TPH, 5-hydroxytryptophan (5-HTP, or serotonin. Together, these results highlight a role for serotonin in melanogenesis, perhaps as a regulatory signal or as a pigment substrate. To our knowledge, this is the first example of this relationship to be reported outside of mammalian systems.

  10. Studies on the application of tryptophan metabolites as indicators of acute radiation damage and their modification

    International Nuclear Information System (INIS)

    Streffer, C.

    1979-01-01

    It has been the aim of the investigations to continue earlier studies on the amplication of tryptophan metabolites as biochemical indicators after irradiation. These metabolites are of interest as they apparently indicate radiation effects in contrast to other metabolites like taurine and deoxycytidine in a dose range which leads to acute radiation sickness with the consequence of death. This assumption has been confirmed by the results of these studies. Measurements in the urine of rats demonstrate that the excretion of kynurenic acid and of xanthurenic acid as well as especially the ratio of kynurenic acid/anthranilic acid increases considerably in those animals which die some days later. The excretion of the surviving anilic acid increases considerably in those animals which die some days later. The excretion of the surviving animals is characteristical different. This abnormal excretion is induced by changes of specific, hepatic enzyme activities. The investigations have shown that the effects on the enzyme activities apppear not only after X-rays irradiation but also after neutrons. The studies, which have been performed with human material on the NAD-metabolism, demonstrate that with respect to the enzyme activities in the spleen as well as to the urinary excretion the same or similar effects, which have been found with animal experiments, can be expected. (orig.) 891 MG/orig. 892 CKA [de

  11. Specificity of the Acute Tryptophan and Tyrosine plus Phenylalanine Depletion and Loading Tests Part II:

    Directory of Open Access Journals (Sweden)

    Abdulla A.-B. Badawy

    2010-01-01

    Full Text Available Current formulations for acute tryptophan (Trp or tyrosine (Tyr plus phenylalanine (Phe depletion and loading cause undesirable decreases in ratios of Trp or Tyr + Phe to competing amino acids (CAA, thus undermining the specificities of these tests. Branched-chain amino acids (BCAA cause these unintended decreases, and lowering their content in a new balanced control formulation in the present study led to normalization of all ratios. Four groups (n = 12 each of adults each received one of four 50 g control formulations, with 0% (traditional, 20%, 30%, or 40% less of the BCAA. The free and total [Trp]/[CAA] and [Phe + Tyr]/[BCAA+ Trp] ratios all decreased significantly during the first 5 h following the traditional formulation, but were fully normalized by the formulation containing 40% less of the BCAA. We recommend the latter as a balanced control formulation and propose adjustments in the depletion and loading formulations to enhance their specificities for 5-HT and the catecholamines.

  12. Interactions between the nuclear matrix and an enhancer of the tryptophan oxygenase gene

    International Nuclear Information System (INIS)

    Kaneoka, Hidenori; Miyake, Katsuhide; Iijima, Shinji

    2009-01-01

    The gene for tryptophan oxygenase (TO) is expressed in adult hepatocytes in a tissue- and differentiation-specific manner. The TO promoter has two glucocorticoid-responsive elements (GREs), and its expression is regulated by glucocorticoid hormone in the liver. We found a novel GRE in close proximity to a scaffold/matrix attachment region (S/MAR) that was located around -8.5 kb from the transcriptional start site of the TO gene by electrophoretic mobility shift and chromatin immunoprecipitation (ChIP) assays. A combination of nuclear fractionation and quantitative PCR analysis showed that the S/MAR was tethered to the nuclear matrix in both fetal and adult hepatocytes. ChIP assay showed that, in adult hepatocytes, the S/MAR-GRE and the promoter proximal regions interacted with lamin and heterogeneous nuclear ribonucleoprotein U in a dexamethasone dependent manner, but this was not the case in fetal cells, suggesting that developmental stage-specific expression of the TO gene might rely on the binding of the enhancer (the -8.5 kb S/MAR-GRE) and the promoter to the inner nuclear matrix.

  13. Tryptophan depletion affects the autonomic stress response in generalized social anxiety disorder.

    Science.gov (United States)

    van Veen, J Frederieke; van Vliet, Irene M; de Rijk, Roel H; van Pelt, Johannes; Mertens, Bart; Fekkes, Durk; Zitman, Frans G

    2009-11-01

    In generalized social anxiety disorder (gSAD), serotonergic dysfunctions are found, as well as abnormalities of the autonomic nervous system (ANS) in basal conditions and of the hypothalamic pituitary adrenal (HPA) axis in response to psychological challenges. These findings raise the question whether these phenomena are interrelated. Therefore we designed a study in which two groups with nine pair wise age and gender matched gSAD patients (total of 10 men and 8 women), who were successfully treated with a selective serotonin reuptake inhibitor (SSRI), underwent a tryptophan depletion challenge (TD) or a placebo condition. A TD procedure temporarily decreases serotonergic neurotransmission. In order to activate the stress system the TD/placebo challenge was combined with a public speaking task. We assessed ANS responses, as measured with the promising new marker salivary alpha-amylase (sAA), and HPA-axis responses, as measured with salivary cortisol. The most important result was that the TD group showed a significant larger sAA response to the public speaking task as compared to the placebo group, reflecting hyperresponsivity of the ANS in this group, whereas no differences were seen in cortisol responses. This suggests that in gSAD there is a vulnerability of the ANS more than the HPA-axis.

  14. Determination of adenine based on the fluorescence recovery of the L-Tryptophan-Cu(2+) complex.

    Science.gov (United States)

    Duan, Ruilin; Li, Chunyan; Liu, Shaopu; Liu, Zhongfang; Li, Yuanfang; Yuan, Yusheng; Hu, Xiaoli

    2016-01-05

    A simple and sensitive method for determination of adenine was developed based on fluorescence quenching and recovery of L-Tryptophan (L-Trp). The fluorescence of L-Trp could efficiently quenched by copper ion compared with other common metal ions. Upon addition of adenine (Ade) in L-Trp-Cu(II) system, the fluorescence was reoccurred. Under the optimum conditions, the recovery fluorescence intensity was linearly correlated with the concentration of adenine in the range from 0.34 to 25.0μmolL(-1), with a correlation coefficient (R(2)) of 0.9994. The detection limit (3σ/k) was 0.046μmolL(-1), indicating that this method could applied to detect trace adenine. In this study, amino acids including L-Trp, D-Trp, L-Tyr, D-Tyr, L-Phe, D-Phe were investigated and only L-Trp could well chelated copper ion. Additionally, the mechanism of quench and recovery also were discussed and the method was successfully applied to detect the adenine in DNA with satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. A small-molecule allosteric inhibitor of Mycobacterium tuberculosis tryptophan synthase

    Energy Technology Data Exchange (ETDEWEB)

    Wellington, Samantha; Nag, Partha P.; Michalska, Karolina; Johnston, Stephen E.; Jedrzejczak, Robert P.; Kaushik, Virendar K.; Clatworthy, Anne E.; Siddiqi, Noman; McCarren, Patrick; Bajrami, Besnik; Maltseva, Natalia I.; Combs, Senya; Fisher, Stewart L.; Joachimiak, Andrzej; Schreiber, Stuart L.; Hung, Deborah T.

    2017-07-03

    New antibiotics with novel targets are greatly needed. Bacteria have numerous essential functions, but only a small fraction of such processes—primarily those involved in macromolecular synthesis—are inhibited by current drugs. Targeting metabolic enzymes has been the focus of recent interest, but effective inhibitors have been difficult to identify. We describe a synthetic azetidine derivative, BRD4592, that kills Mycobacterium tuberculosis (Mtb) through allosteric inhibition of tryptophan synthase (TrpAB), a previously untargeted, highly allosterically regulated enzyme. BRD4592 binds at the TrpAB a–b-subunit interface and affects multiple steps in the enzyme’s overall reaction, resulting in inhibition not easily overcome by changes in metabolic environment. We show that TrpAB is required for the survival of Mtb and Mycobacterium marinum in vivo and that this requirement may be independent of an adaptive immune response. This work highlights the effectiveness of allosteric inhibition for targeting proteins that are naturally highly dynamic and that are essential in vivo, despite their apparent dispensability under in vitro conditions, and suggests a framework for the discovery of a next generation of allosteric inhibitors.

  16. A small-molecule allosteric inhibitor of Mycobacterium tuberculosis tryptophan synthase

    Energy Technology Data Exchange (ETDEWEB)

    Wellington, Samantha; Nag, Partha P.; Michalska, Karolina; Johnston, Stephen E.; Jedrzejczak, Robert P.; Kaushik, Virendar K.; Clatworthy, Anne E.; Siddiqi, Noman; McCarren, Patrick; Bajrami, Besnik; Maltseva, Natalia I.; Combs, Senya; Fisher, Stewart L.; Joachimiak, Andrzej; Schreiber, Stuart L.; Hung, Deborah T.

    2017-07-03

    New antibiotics with novel targets are greatly needed. Bacteria have numerous essential functions, but only a small fraction of such processes—primarily those involved in macromolecular synthesis—are inhibited by current drugs. Targeting metabolic enzymes has been the focus of recent interest, but effective inhibitors have been difficult to identify. We describe a synthetic azetidine derivative, BRD4592, that kills Mycobacterium tuberculosis (Mtb) through allosteric inhibition of tryptophan synthase (TrpAB), a previously untargeted, highly allosterically regulated enzyme. BRD4592 binds at the TrpAB α–β-subunit interface and affects multiple steps in the enzyme's overall reaction, resulting in inhibition not easily overcome by changes in metabolic environment. We show that TrpAB is required for the survival of Mtb and Mycobacterium marinum in vivo and that this requirement may be independent of an adaptive immune response. This work highlights the effectiveness of allosteric inhibition for targeting proteins that are naturally highly dynamic and that are essential in vivo, despite their apparent dispensability under in vitro conditions, and suggests a framework for the discovery of a next generation of allosteric inhibitors.

  17. Enhanced longevity by ibuprofen, conserved in multiple species, occurs in yeast through inhibition of tryptophan import.

    Directory of Open Access Journals (Sweden)

    Chong He

    2014-12-01

    Full Text Available The common non-steroidal anti-inflammatory drug ibuprofen has been associated with a reduced risk of some age-related pathologies. However, a general pro-longevity role for ibuprofen and its mechanistic basis remains unclear. Here we show that ibuprofen increased the lifespan of Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster, indicative of conserved eukaryotic longevity effects. Studies in yeast indicate that ibuprofen destabilizes the Tat2p permease and inhibits tryptophan uptake. Loss of Tat2p increased replicative lifespan (RLS, but ibuprofen did not increase RLS when Tat2p was stabilized or in an already long-lived strain background impaired for aromatic amino acid uptake. Concomitant with lifespan extension, ibuprofen moderately reduced cell size at birth, leading to a delay in the G1 phase of the cell cycle. Similar changes in cell cycle progression were evident in a large dataset of replicatively long-lived yeast deletion strains. These results point to fundamental cell cycle signatures linked with longevity, implicate aromatic amino acid import in aging and identify a largely safe drug that extends lifespan across different kingdoms of life.

  18. Enhanced Longevity by Ibuprofen, Conserved in Multiple Species, Occurs in Yeast through Inhibition of Tryptophan Import

    Science.gov (United States)

    He, Chong; Tsuchiyama, Scott K.; Nguyen, Quynh T.; Plyusnina, Ekaterina N.; Terrill, Samuel R.; Sahibzada, Sarah; Patel, Bhumil; Faulkner, Alena R.; Shaposhnikov, Mikhail V.; Tian, Ruilin; Tsuchiya, Mitsuhiro; Kaeberlein, Matt; Moskalev, Alexey A.; Kennedy, Brian K.; Polymenis, Michael

    2014-01-01

    The common non-steroidal anti-inflammatory drug ibuprofen has been associated with a reduced risk of some age-related pathologies. However, a general pro-longevity role for ibuprofen and its mechanistic basis remains unclear. Here we show that ibuprofen increased the lifespan of Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster, indicative of conserved eukaryotic longevity effects. Studies in yeast indicate that ibuprofen destabilizes the Tat2p permease and inhibits tryptophan uptake. Loss of Tat2p increased replicative lifespan (RLS), but ibuprofen did not increase RLS when Tat2p was stabilized or in an already long-lived strain background impaired for aromatic amino acid uptake. Concomitant with lifespan extension, ibuprofen moderately reduced cell size at birth, leading to a delay in the G1 phase of the cell cycle. Similar changes in cell cycle progression were evident in a large dataset of replicatively long-lived yeast deletion strains. These results point to fundamental cell cycle signatures linked with longevity, implicate aromatic amino acid import in aging and identify a largely safe drug that extends lifespan across different kingdoms of life. PMID:25521617

  19. Evaluation of Urinary Tryptophan Metabolite Levels in Non-diabetic Compared to Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Loredana Elena OLAR

    2017-11-01

    Full Text Available Diabetes mellitus is one of the most common metabolic disorders in animals. Thus, currently, it is imperative to introduce non-invasive, economical and rapid methods for the investigation of diabetes in animals. In this study, the urine samples collected from 10 non-diabetic and 10 streptozotocin-induced diabetic rats were investigated by the spectrofluorimetric technique. Emission spectra for the urine samples were obtained following an excitation wavelength of 280 and 400 nm. The investigated fluorophores were mainly tryptophan metabolites, and significant differences resulted between the mean heights of the emission bands attributed to these fluorophore compounds in diabetic compared to non-diabetic rats. The shape of the spectral windings after the utilization of these two excitation wavelengths was almost similar for diabetic and non-diabetic rats; however, there were some discriminatory elements between the two types of investigated samples. In conclusion, the obtained urine fluorescence spectra allow a clear differentiation between diabetic and non-diabetic rats.

  20. Low-dose tryptophan depletion in recovered depressed women induces impairments in autobiographical memory specificity.

    Science.gov (United States)

    Haddad, Anneke D M; Williams, J Mark G; McTavish, Sarah F B; Harmer, Catherine J

    2009-12-01

    Depressed patients perform poorly on tests of autobiographical memory specificity (AMS); this may have negative consequences for other important cognitive abilities, delays recovery from mood episodes, and, in recovered patients, may mediate vulnerability to future episodes. Although the cognitive mechanisms underlying AMS deficits are beginning to be understood, the neurobiological mechanisms remain unclear. Serotonin is implicated in both depression and long-term memory; therefore, temporary lowering of brain serotonin function via acute tryptophan depletion (ATD) offers a means of studying the role of serotonin in autobiographical memory specificity. In this study, 24 previously depressed women underwent low-dose ATD or sham depletion and completed tests of initial and delayed memory, recollection- and familiarity-based recognition, and AMS. ATD did not differentially affect state mood. Compared with sham depletion, ATD impaired immediate recall on the Auditory Verbal Learning Test. Although ATD did not differentially impair recollection- and familiarity-based recognition, it did slow recognition of positive words. ATD also reduced autobiographical memory specificity in response to negative cue words. The results confirm previous findings that low-dose ATD can reinstate depression-congruent biases in cognition without causing depressive mood in vulnerable populations. The ATD-induced reduction in memory specificity suggests that serotonergic dysfunction may mediate depressive deficits in autobiographical memory; the interaction of cognitive and neurobiological vulnerability mechanisms is discussed.

  1. Dissection of seroreactivity against the tryptophan-rich motif of the feline immunodeficiency virus transmembrane glycoprotein

    International Nuclear Information System (INIS)

    Freer, Giulia; Giannecchini, Simone; Tissot, Alain; Bachmann, Martin F.; Rovero, Paolo; Serres, Pierre Francoise; Bendinelli, Mauro

    2004-01-01

    Immunogenicity of the tryptophan-rich motif (TrpM) in the membrane-proximal ectodomain of the transmembrane (TM) glycoprotein of feline immunodeficiency virus (FIV) was investigated. Peptide 59, a peptide containing the TrpM of the TM of FIV, was covalently coupled to Qβ phage virus-like particles (Qβ-59) in the attempt to induce potent anti-TrpM B cell responses in cats. All Qβ-59 immunized cats, but not cats that received a mixture of uncoupled Qβ and peptide 59, developed antibodies that reacted with a same epitope in extensive binding and binding competition assays. The epitope recognized was composed of three amino acids, two of which are adjacent. However, Qβ-59-immune sera failed to recognize whole FIV in all binding and neutralization assays performed. Furthermore, no reactivity against the TrpM was detected by screening sera from FIV-infected cats that had reacted with TM peptides, confirming that this epitope does not seem to be serologically functional in the FIV virion. The data suggest that TrpM may not be a suitable target for antiviral vaccine design

  2. Effects of acute tryptophan depletion on memory, attention and executive functions: a systematic review.

    Science.gov (United States)

    Mendelsohn, Daniel; Riedel, Wim J; Sambeth, Anke

    2009-06-01

    The serotonergic system is implicated in the regulation of mood and cognition. Acute tryptophan depletion (ATD) is an experimental procedure for lowering central serotonin levels. Here, the effects of ATD on psychomotor processing, declarative memory, working memory, executive functions and attention are discussed. The most robust finding is that ATD impairs the consolidation of episodic memory for verbal information. Semantic memory appears to be unaffected by ATD although a limited variety of tasks examined effects in this domain. Similarly, evidence suggests ATD does not influence verbal, spatial and affective working memory. Most studies investigating effects on executive functions have produced non-specific or negative findings. In terms of attention, ATD either does not affect or may improve focused attention and ATD likely does not impact sustained and divided attention or attentional set-shifting. Although ATD is known to affect mood in certain vulnerable populations, the effects of ATD on cognition in non-vulnerable participants are independent of mood changes. Suggestions for future directions and implications for psychiatric illnesses are discussed.

  3. Evaluation of residue-residue contact predictions in CASP9

    KAUST Repository

    Monastyrskyy, Bohdan; Fidelis, Krzysztof; Tramontano, Anna; Kryshtafovych, Andriy

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures

  4. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... for policy makers and courts in awarding damages in a large number of real-world accident cases....

  5. Does tryptophan degradation along the kynurenine pathway mediate the association between pro-inflammatory immune activity and depressive symptoms?

    Science.gov (United States)

    Quak, Jacqueline; Doornbos, Bennard; Roest, Annelieke M; Duivis, Hester E; Vogelzangs, Nicole; Nolen, Willem A; Penninx, Brenda W J H; Kema, Ido P; de Jonge, Peter

    2014-07-01

    Several studies have suggested that induced tryptophan (TRP) degradation through the kynurenine (KYN) pathway by the enzyme indoleamine 2,3-dioxygenase (IDO) is implicated in the relation between depression and inflammation. We investigated the role of tryptophan degradation in the relationship between inflammatory markers and depressive symptoms in the Netherlands Study of Depression and Anxiety (NESDA) and hypothesized that tryptophan degradation would mediate (part of) this association. 2812 Participants of NESDA were included in this study including 1042 persons with current major depressive disorder (MDD). Assessments of C-reactive protein (CRP), interleukin (IL)-6, tumor-necrosis factor (TNF)-α, KYN and TRP were obtained from fasting blood samples at the baseline assessment. Tryptophan degradation was estimated by calculating the ratio [KYN/TRP]. Depressive symptoms were measured with the Inventory of Depressive Symptomatology. Significant associations between inflammation and depressive symptoms were found for CRP and IL-6, for the total group and the subgroup of patients with current MDD. Adjustment for KYN/TRP did not attenuate these associations. There were no significant indirect effects for CRP on depressive symptoms mediated by KYN/TRP for the whole group (B=-0.032; 95% CI: -0.103 to 0.028) and for the subgroup of patients with current MDD (B=0.059; 95% CI: -0.037 to 0.165). Also IL-6 did not indirectly affect depressive symptoms through KYN/TRP in the total group (B=-0.023; 95% CI: -0.093 to 0.045) and in the MDD subgroup B=0.052; 95% CI: -0.019 to 0.144). Finally, no significant relation between depressive symptoms and KYN/TRP was found in the whole group (β=-0.019, p=0.311) nor in the subgroup with MDD (β=0.025, p=0.424). We did not find indications for tryptophan degradation, measured by KYN/TRP, to mediate the relationship between inflammation and depressive symptoms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The selenazal drug ebselen potently inhibits indoleamine 2,3-dioxygenase by targeting enzyme cysteine residues.

    Science.gov (United States)

    Terentis, Andrew C; Freewan, Mohammed; Sempértegui Plaza, Tito S; Raftery, Mark J; Stocker, Roland; Thomas, Shane R

    2010-01-26

    The heme enzyme indoleamine 2,3-dioxygenase (IDO) plays an important immune regulatory role by catalyzing the oxidative degradation of l-tryptophan. Here we show that the selenezal drug ebselen is a potent IDO inhibitor. Exposure of human macrophages to ebselen inhibited IDO activity in a manner independent of changes in protein expression. Ebselen inhibited the activity of recombinant human IDO (rIDO) with an apparent inhibition constant of 94 +/- 17 nM. Optical and resonance Raman spectroscopy showed that ebselen altered the active site heme of rIDO by inducing a transition of the ferric heme iron from the predominantly high- to low-spin form and by lowering the vibrational frequency of the Fe-CO stretch of the CO complex, indicating an opening of the distal heme pocket. Substrate binding studies showed that ebselen enhanced nonproductive l-tryptophan binding, while circular dichroism indicated that the drug reduced the helical content and protein stability of rIDO. Thiol labeling and mass spectrometry revealed that ebselen reacted with multiple cysteine residues of IDO. Removal of cysteine-bound ebselen with dithiothreitol reversed the effects of the drug on the heme environment and significantly restored enzyme activity. These findings indicate that ebselen inhibits IDO activity by reacting with the enzyme's cysteine residues that result in changes to protein conformation and active site heme, leading to an increase in the level of nonproductive substrate binding. This study highlights that modification of cysteine residues is a novel and effective means of inhibiting IDO activity. It also suggests that IDO is under redox control and that the enzyme represents a previously unrecognized in vivo target of ebselen.

  7. Machine for compacting solid residues

    International Nuclear Information System (INIS)

    Herzog, J.

    1981-11-01

    Machine for compacting solid residues, particularly bulky radioactive residues, constituted of a horizontally actuated punch and a fixed compression anvil, in which the residues are first compacted horizontally and then vertically. Its salient characteristic is that the punch and the compression anvil have embossments on the compression side and interpenetrating plates in the compression position [fr

  8. Quadratic residues and non-residues selected topics

    CERN Document Server

    Wright, Steve

    2016-01-01

    This book offers an account of the classical theory of quadratic residues and non-residues with the goal of using that theory as a lens through which to view the development of some of the fundamental methods employed in modern elementary, algebraic, and analytic number theory. The first three chapters present some basic facts and the history of quadratic residues and non-residues and discuss various proofs of the Law of Quadratic Reciprosity in depth, with an emphasis on the six proofs that Gauss published. The remaining seven chapters explore some interesting applications of the Law of Quadratic Reciprocity, prove some results concerning the distribution and arithmetic structure of quadratic residues and non-residues, provide a detailed proof of Dirichlet’s Class-Number Formula, and discuss the question of whether quadratic residues are randomly distributed. The text is a valuable resource for graduate and advanced undergraduate students as well as for mathematicians interested in number theory.

  9. Is there a relationship between tryptophan dietary intake and plasma levels of indoxyl sulfate in chronic kidney disease patients on hemodialysis?

    Directory of Open Access Journals (Sweden)

    Jessyca Sousa de Brito

    Full Text Available Abstract Introduction: Gut microbiota is involved in generation of uremic toxins in chronic kidney disease (CKD patients on hemodialysis (HD, like indoxyl sulfate (IS that is originated from tryptophan amino acid fermentation. Objective: To evaluate the tryptophan intake by chronic renal failure patients on HD and its possible relationship with IS plasma levels. Methods: Participated of the study 46 patients with CKD on HD regular program (56.5% men; 52.7 ± 10.3 years; 63 (32.2-118.2 months on HD; BMI 25.6 ± 4.9 kg/m2. The tryptophan intake was evaluated by a 24-hours dietary recall (R-24h performed on 3 different days. Routine biochemical tests and anthropometric measurements were evaluated. IS plasma levels were determined by High Performance Liquid Chromatography (HPLC with fluorescent detection and the interleukin-6 (IL-6 plasma levels by immunoenzymatic method (ELISA, Enzyme Linked Immunosorbent Assay. Results: The average of tryptophan intake was according to recommendation, but IS plasma levels (35.0 ± 11.9 mg/L were elevated, however according to the EUTox values for uremic individuals. There was no correlation between the tryptophan intake and IS plasma levels. However, there was positive correlation between protein intake and tryptophan and variables used to evaluate lean body mass, and moreover, IS levels were positively associated with IL-6 (r = 0.6: p = 0.01. Conclusion: The present study suggests that tryptophan dietary intake may not be a determinant factor to IS levels. However, it suggests that gut microbiota may play an important role in systemic inflammation in patients with CKD.

  10. Is there a relationship between tryptophan dietary intake and plasma levels of indoxyl sulfate in chronic kidney disease patients on hemodialysis?

    Science.gov (United States)

    Brito, Jessyca Sousa de; Borges, Natália Alvarenga; Dolenga, Carla Juliana Ribeiro; Carraro-Eduardo, José Carlos; Nakao, Lia Sumie; Mafra, Denise

    2016-12-01

    Gut microbiota is involved in generation of uremic toxins in chronic kidney disease (CKD) patients on hemodialysis (HD), like indoxyl sulfate (IS) that is originated from tryptophan amino acid fermentation. To evaluate the tryptophan intake by chronic renal failure patients on HD and its possible relationship with IS plasma levels. Participated of the study 46 patients with CKD on HD regular program (56.5% men; 52.7 ± 10.3 years; 63 (32.2-118.2) months on HD; BMI 25.6 ± 4.9 kg/m2). The tryptophan intake was evaluated by a 24-hours dietary recall (R-24h) performed on 3 different days. Routine biochemical tests and anthropometric measurements were evaluated. IS plasma levels were determined by High Performance Liquid Chromatography (HPLC) with fluorescent detection and the interleukin-6 (IL-6) plasma levels by immunoenzymatic method (ELISA, Enzyme Linked Immunosorbent Assay). The average of tryptophan intake was according to recommendation, but IS plasma levels (35.0 ± 11.9 mg/L) were elevated, however according to the EUTox values for uremic individuals. There was no correlation between the tryptophan intake and IS plasma levels. However, there was positive correlation between protein intake and tryptophan and variables used to evaluate lean body mass, and moreover, IS levels were positively associated with IL-6 (r = 0.6: p = 0.01). The present study suggests that tryptophan dietary intake may not be a determinant factor to IS levels. However, it suggests that gut microbiota may play an important role in systemic inflammation in patients with CKD.

  11. Effects of chronic fluoxetine treatment on neurogenesis and tryptophan hydroxylase expression in adolescent and adult rats.

    Science.gov (United States)

    Klomp, Anne; Václavů, Lena; Meerhoff, Gideon F; Reneman, Liesbeth; Lucassen, Paul J

    2014-01-01

    The antidepressant drug fluoxetine (Prozac) has been increasingly prescribed to children and adolescents with depressive disorders despite a lack of thorough understanding of its therapeutic effects in the paediatric population and of its putative neurodevelopmental effects. Within the framework of PRIOMEDCHILD ERA-NET, we investigated; a) effects of chronic fluoxetine treatment on adult hippocampal neurogenesis, a structural readout relevant for antidepressant action and hippocampal development; b) effects on tryptophan hydroxylase (TPH) expression, a measure of serotonin synthesis; c) whether treatment effects during adolescence differed from treatment at an adult age, and d) whether they were subregion-specific. Stereological quantification of the number of proliferating (Ki-67+) cells and of the number of young migratory neurons (doublecortin+), revealed a significant age-by-treatment interaction effect, indicating that fluoxetine affects both proliferation and neurogenesis in adolescent-treated rats differently than it does in adult-treated rats. In terms of subregional differences, fluoxetine enhanced proliferation mainly in the dorsal parts of the hippocampus, and neurogenesis in both the suprapyramidal and infrapyramidal blades of the dentate gyrus in adolescent-treated rats, while no such differences were seen in adult-treated rats. Fluoxetine exerted similar age-by-treatment interaction effects on TPH cells mainly in the ventral portion of the dorsal raphe nucleus. We conclude that fluoxetine exerts divergent effects on structural plasticity and serotonin synthesis in adolescent versus adult-treated rats. These preliminary data indicate a differential sensitivity of the adolescent brain to this drug and thus warrant further research into their behavioural and translational aspects. Together with recent related findings, they further call for caution in prescribing these drugs to the adolescent population.

  12. Effects of chronic fluoxetine treatment on neurogenesis and tryptophan hydroxylase expression in adolescent and adult rats.

    Directory of Open Access Journals (Sweden)

    Anne Klomp

    Full Text Available The antidepressant drug fluoxetine (Prozac has been increasingly prescribed to children and adolescents with depressive disorders despite a lack of thorough understanding of its therapeutic effects in the paediatric population and of its putative neurodevelopmental effects. Within the framework of PRIOMEDCHILD ERA-NET, we investigated; a effects of chronic fluoxetine treatment on adult hippocampal neurogenesis, a structural readout relevant for antidepressant action and hippocampal development; b effects on tryptophan hydroxylase (TPH expression, a measure of serotonin synthesis; c whether treatment effects during adolescence differed from treatment at an adult age, and d whether they were subregion-specific. Stereological quantification of the number of proliferating (Ki-67+ cells and of the number of young migratory neurons (doublecortin+, revealed a significant age-by-treatment interaction effect, indicating that fluoxetine affects both proliferation and neurogenesis in adolescent-treated rats differently than it does in adult-treated rats. In terms of subregional differences, fluoxetine enhanced proliferation mainly in the dorsal parts of the hippocampus, and neurogenesis in both the suprapyramidal and infrapyramidal blades of the dentate gyrus in adolescent-treated rats, while no such differences were seen in adult-treated rats. Fluoxetine exerted similar age-by-treatment interaction effects on TPH cells mainly in the ventral portion of the dorsal raphe nucleus. We conclude that fluoxetine exerts divergent effects on structural plasticity and serotonin synthesis in adolescent versus adult-treated rats. These preliminary data indicate a differential sensitivity of the adolescent brain to this drug and thus warrant further research into their behavioural and translational aspects. Together with recent related findings, they further call for caution in prescribing these drugs to the adolescent population.

  13. Experimental Evolution of a Green Fluorescent Protein Composed of 19 Unique Amino Acids without Tryptophan

    Science.gov (United States)

    Kawahara-Kobayashi, Akio; Hitotsuyanagi, Mitsuhiro; Amikura, Kazuaki; Kiga, Daisuke

    2014-04-01

    At some stage of evolution, genes of organisms may have encoded proteins that were synthesized using fewer than 20 unique amino acids. Similar to evolution of the natural 19-amino-acid proteins GroEL/ES, proteins composed of 19 unique amino acids would have been able to evolve by accumulating beneficial mutations within the 19-amino-acid repertoire encoded in an ancestral genetic code. Because Trp is thought to be the last amino acid included in the canonical 20-amino-acid repertoire, this late stage of protein evolution could be mimicked by experimental evolution of 19-amino-acid proteins without tryptophan (Trp). To further understand the evolution of proteins, we tried to mimic the evolution of a 19-amino-acid protein involving the accumulation of beneficial mutations using directed evolution by random mutagenesis on the whole targeted gene sequence. We created active 19-amino-acid green fluorescent proteins (GFPs) without Trp from a poorly fluorescent 19-amino-acid mutant, S1-W57F, by using directed evolution with two rounds of mutagenesis and selection. The N105I and S205T mutations showed beneficial effects on the S1-W57F mutant. When these two mutations were combined on S1-W57F, we observed an additive effect on the fluorescence intensity. In contrast, these mutations showed no clear improvement individually or in combination on GFPS1, which is the parental GFP mutant composed of 20 amino acids. Our results provide an additional example for the experimental evolution of 19-amino-acid proteins without Trp, and would help understand the mechanisms underlying the evolution of 19-amino-acid proteins. (236 words)

  14. Biochemical characterization of an L-tryptophan dehydrogenase from the photoautotrophic cyanobacterium Nostoc punctiforme.

    Science.gov (United States)

    Ogura, Ryutaro; Wakamatsu, Taisuke; Mutaguchi, Yuta; Doi, Katsumi; Ohshima, Toshihisa

    2014-06-10

    An NAD(+)-dependent l-tryptophan dehydrogenase from Nostoc punctiforme NIES-2108 (NpTrpDH) was cloned and overexpressed in Escherichia coli. The recombinant NpTrpDH with a C-terminal His6-tag was purified to homogeneity using a Ni-NTA agarose column, and was found to be a homodimer with a molecular mass of 76.1kDa. The enzyme required NAD(+) and NADH as cofactors for oxidative deamination and reductive amination, respectively, but not NADP(+) or NADPH. l-Trp was the preferred substrate for deamination, though l-Phe was deaminated at a much lower rate. The enzyme exclusively aminated 3-indolepyruvate; phenylpyruvate was inert. The pH optima for the deamination of l-Trp and amination of 3-indolpyruvate were 11.0 and 7.5, respectively. For deamination of l-Trp, maximum enzymatic activity was observed at 45°C. NpTrpDH retained more than 80% of its activity after incubation for 30min at pHs ranging from 5.0 to 11.5 or incubation for 10min at temperatures up to 40°C. Unlike l-Trp dehydrogenases from higher plants, NpTrpDH activity was not activated by metal ions. Typical Michaelis-Menten kinetics were observed for NAD(+) and l-Trp for oxidative deamination, but with reductive amination there was marked substrate inhibition by 3-indolepyruvate. NMR analysis of the hydrogen transfer from the C4 position of the nicotinamide moiety of NADH showed that NpTrpDH has a pro-S (B-type) stereospecificity similar to the Glu/Leu/Phe/Val dehydrogenase family. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Tryptophan hydroxylase type 2 variants modulate severity and outcome of addictive behaviors in Parkinson's disease.

    Science.gov (United States)

    Cilia, Roberto; Benfante, Roberta; Asselta, Rosanna; Marabini, Laura; Cereda, Emanuele; Siri, Chiara; Pezzoli, Gianni; Goldwurm, Stefano; Fornasari, Diego

    2016-08-01

    Impulse control disorders and compulsive medication intake may occur in a minority of patients with Parkinson's disease (PD). We hypothesize that genetic polymorphisms associated with addiction in the general population may increase the risk for addictive behaviors also in PD. Sixteen polymorphisms in candidate genes belonging to five neurotransmitter systems (dopaminergic, catecholaminergic, serotonergic, glutamatergic, opioidergic) and the BDNF were screened in 154 PD patients with addictive behaviors and 288 PD control subjects. Multivariate analysis investigated clinical and genetic predictors of outcome (remission vs. persistence/relapse) after 1 year and at the last follow-up (5.1 ± 2.5 years). Addictive behaviors were associated with tryptophan hydroxylase type 2 (TPH2) and dopamine transporter gene variants. A subsequent analysis within the group of cases showed a robust association between TPH2 genotype and the severity of addictive behaviors, which survived Bonferroni correction for multiple testing. At multivariate analysis, TPH2 genotype resulted the strongest predictor of no remission at the last follow-up (OR[95%CI], 7.4[3.27-16.78] and 13.2[3.89-44.98] in heterozygous and homozygous carriers, respectively, p medication dose reduction was not a predictor. TPH2 haplotype analysis confirmed the association with more severe symptoms and lower remission rates in the short- and the long-term (p addictive behaviors in PD, modulating the severity of symptoms and the rate of remission at follow-up. If confirmed in larger independent cohorts, TPH2 genotype may become a useful biomarker for the identification of at-risk individuals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. No Tryptophan, Tyrosine and Phenylalanine Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder.

    Directory of Open Access Journals (Sweden)

    Catharina Elisabeth Bergwerff

    Full Text Available The aim of the current study was to explore the role of aromatic amino acids (AAAs in blood in relation to attention-deficit/hyperactivity disorder (ADHD. Given their impact on the synthesis of serotonin and dopamine, decreased concentrations of the AAAs tryptophan, tyrosine and phenylalanine in blood may contribute to the expression of ADHD symptoms. Decreased AAA blood concentrations, in turn, may be related to lowered dietary protein intake or to abnormal AAA catabolism, as evidenced by increased urinary AAA concentrations.Eighty-three children with ADHD (75% males and 72 typically developing (TD children (51% males, aged 6 to 13 years, participated in the study. AAA concentrations were assessed in blood spots and an 18-hour urinary sample. A nutritional diary was filled out by parents to calculate dietary protein intake. Parent and teacher questionnaires assessed symptoms of ADHD, oppositional defiant disorder, conduct disorder, and autism spectrum disorder.Children with ADHD showed normal AAA concentrations in blood spots and urine, as well as normal protein intake compared to controls. No associations between AAA concentrations and symptoms of ADHD or comorbid psychiatric disorders were found.This study is the first to explore AAA metabolism in children with ADHD using a well-defined and relatively large sample. We found that AAA deficiencies are not related to ADHD. The results do not support treatment with AAA supplements in children with ADHD. Future studies regarding the cause of serotonin and dopamine alterations in ADHD should focus on other explanations, such as effects of altered transport of AAAs.

  17. Impact of the Gut Microbiota on Intestinal Immunity Mediated by Tryptophan Metabolism

    Science.gov (United States)

    Gao, Jing; Xu, Kang; Liu, Hongnan; Liu, Gang; Bai, Miaomiao; Peng, Can; Li, Tiejun; Yin, Yulong

    2018-01-01

    The gut microbiota influences the health of the host, especially with regard to gut immune homeostasis and the intestinal immune response. In addition to serving as a nutrient enhancer, L-tryptophan (Trp) plays crucial roles in the balance between intestinal immune tolerance and gut microbiota maintenance. Recent discoveries have underscored that changes in the microbiota modulate the host immune system by modulating Trp metabolism. Moreover, Trp, endogenous Trp metabolites (kynurenines, serotonin, and melatonin), and bacterial Trp metabolites (indole, indolic acid, skatole, and tryptamine) have profound effects on gut microbial composition, microbial metabolism, the host's immune system, the host-microbiome interface, and host immune system–intestinal microbiota interactions. The aryl hydrocarbon receptor (AhR) mediates the regulation of intestinal immunity by Trp metabolites (as ligands of AhR), which is beneficial for immune homeostasis. Among Trp metabolites, AhR ligands consist of endogenous metabolites, including kynurenine, kynurenic acid, xanthurenic acid, and cinnabarinic acid, and bacterial metabolites, including indole, indole propionic acid, indole acetic acid, skatole, and tryptamine. Additional factors, such as aging, stress, probiotics, and diseases (spondyloarthritis, irritable bowel syndrome, inflammatory bowel disease, colorectal cancer), which are associated with variability in Trp metabolism, can influence Trp–microbiome–immune system interactions in the gut and also play roles in regulating gut immunity. This review clarifies how the gut microbiota regulates Trp metabolism and identifies the underlying molecular mechanisms of these interactions. Increased mechanistic insight into how the microbiota modulates the intestinal immune system through Trp metabolism may allow for the identification of innovative microbiota-based diagnostics, as well as appropriate nutritional supplementation of Trp to prevent or alleviate intestinal inflammation

  18. Tryptophan Metabolism and Its Relationship with Depression and Cognitive Impairment among HIV-infected Individuals

    Directory of Open Access Journals (Sweden)

    Michael R. Keegan

    2016-01-01

    Full Text Available Objective Cognitive impairment (CI and major depressive disorder (MDD remain prevalent in treated HIV-1 disease; however, the pathogenesis remains elusive. A possible contributing mechanism is immune-mediated degradation of tryptophan (TRP via the kynurenine (KYN pathway, resulting in decreased production of serotonin and accumulation of TRP degradation products. We explored the association of these biochemical pathways and their relationship with CI and MDD in HIV-positive (HIV+ individuals. Methods In a cross-sectional analysis, concentrations of neopterin (NEO, tumor necrosis factor-alpha, TRP, KYN, KYN/TRP ratio, phenylalanine (PHE, tyrosine (TYR, PHE/TYR ratio, and nitrite were assessed in the cerebrospinal fluid (CSF and plasma of HIV+( n = 91 and HIV-negative (HIV- individuals ( n = 66. CI and MDD were assessed via a comprehensive neuropsychological test battery. A Global Deficit Score ≥0.5 was defined as CI. Nonparametric statistical analyses included Kruskal–Wallis and Mann–Whitney U tests, and multivariate logistic regression. Results Following Bonferroni correction, NEO concentrations were found to be greater in CSF and TRP concentration was found to be lower in the plasma of HIV+ versus HIV– individuals, including a subgroup of aviremic (defined as HIV-1 RNA <50 cps/mL HIV+ participants receiving antiretroviral therapy ( n = 44. There was a nonsignificant trend toward higher KYN/TRP ratios in plasma in the HIV+ group ( P = 0.027; Bonferroni corrected α = 0.0027. In a logistic regression model, lower KYN/TRP ratios in plasma were associated with CI and MDD in the overall HIV+ group ( P = 0.038 and P = 0.063, respectively and the aviremic subgroup ( P = 0.066 and P = 0.027, respectively, though this observation was not statistically significant following Bonferroni correction (Bonferroni corrected α = 0.0031. Conclusions We observed a trend toward lower KYN/TRP ratios in aviremic HIV+ patients with CI and MDD.

  19. Protein- and tryptophan-restricted diets induce changes in rat gonadal hormone levels.

    Science.gov (United States)

    Del Angel-Meza, A R.; Feria-Velasco, A; Ontiveros-Martínez, L; Gallardo, L; Gonzalez-Burgos, I; Beas-Zárate, C

    2001-04-01

    The release of gonadotrophic hormones starts at puberty and, along with the subsequent estral cyclicity, is subject to hormonal feedback systems and to the action of diverse neuroactive substances such as gamma amino butyric acid and catecholamines. This study shows the effect of the administration during 40 days of protein-restricted and corn-based (tryptophan- and lysine-deficient) diets on the serotonin concentration in medial hypothalamic fragments as well as in follicle-stimulating luteinizing hormones, 17-beta-estradiol and progesterone serum levels, and estral cyclicity in 60- and 100-day-old rats (young, mature, and in gestation). In young rats, a delay in vaginal aperture development, and a lengthening of the estral cycle to a continuous anestral state was observed, mainly in the group fed corn. This group showed a 25% decrease in the serotonin concentration compared with the protein-restricted group, which exhibited an increase of 9% over the control group. Luteinizing hormone levels decreased in 16% and 13%, whereas follicle-stimulating hormone increased in 13% and 5% in the young animals of restricted groups, respectively, compared with the control group. Serum progesterone levels decreased only in young restricted versus control animals, and no differences were seen among adult and gestational rats. Serum levels of 17-beta-estradiol in restricted animals showed different concentration patterns, mainly in the corn group, which was higher at the 20th gestational day, falling drastically postpartum. The results obtained in this study show serotonin to be a very important factor in the release of gonadotrophic hormones and the start of puberty.

  20. Intragastric preloads of l-tryptophan reduce ingestive behavior via oxytocinergic neural mechanisms in male mice.

    Science.gov (United States)

    Gartner, Sarah N; Aidney, Fraser; Klockars, Anica; Prosser, Colin; Carpenter, Elizabeth A; Isgrove, Kiriana; Levine, Allen S; Olszewski, Pawel K

    2018-06-01

    Human and laboratory animal studies suggest that dietary supplementation of a free essential amino acid, l-tryptophan (TRP), reduces food intake. It is unclear whether an acute gastric preload of TRP decreases consumption and whether central mechanisms underlie TRP-driven hypophagia. We examined the effect of TRP administered via intragastric gavage on energy- and palatability-induced feeding in mice. We sought to identify central mechanisms through which TRP suppresses appetite. Effects of TRP on consumption of energy-dense and energy-dilute tastants were established in mice stimulated to eat by energy deprivation or palatability. A conditioned taste aversion (CTA) paradigm was used to assess whether hypophagia is unrelated to sickness. c-Fos immunohistochemistry was employed to detect TRP-induced activation of feeding-related brain sites and of oxytocin (OT) neurons, a crucial component of satiety circuits. Also, expression of OT mRNA was assessed with real-time PCR. The functional importance of OT in mediating TRP-driven hypophagia was substantiated by showing the ability of OT receptor blockade to abolish TRP-induced decrease in feeding. TRP reduced intake of energy-dense standard chow in deprived animals and energy-dense palatable chow in sated mice. Anorexigenic doses of TRP did not cause a CTA. TRP failed to affect intake of palatable yet calorie-dilute or noncaloric solutions (10% sucrose, 4.1% Intralipid or 0.1% saccharin) even for TRP doses that decreased water intake in thirsty mice. Fos analysis revealed that TRP increases activation of several key feeding-related brain areas, especially in the brain stem and hypothalamus. TRP activated hypothalamic OT neurons and increased OT mRNA levels, whereas pretreatment with an OT antagonist abolished TRP-driven hypophagia. We conclude that intragastric TRP decreases food and water intake, and TRP-induced hypophagia is partially mediated via central circuits that encompass OT. Copyright © 2018 Elsevier Ltd. All

  1. 5-Fluoro-[β-11C]-L-tryptophan is a functional analogue of 5-hydroxy-[β-11C]-L-tryptophan in vitro but not in vivo

    International Nuclear Information System (INIS)

    Eriksson, Olof; Selvaraju, Ramkumar; Borg, Beatrice; Asplund, Veronika; Estrada, Sergio; Antoni, Gunnar

    2013-01-01

    Introduction: 5-Hydroxy-[β- 11 C]-L-tryptophan ([ 11 C]HTP) is an established positron emission tomography (PET) imaging agent for neuroendocrine tumors (NETs). It has also been used for other clinical research purposes in neurology and diabetes. However, its widespread use is limited by the short physical half-life of the radionuclide and a difficult radiosynthesis. Therefore, a Fluorine-18 labeled analogue, 5-[ 18 F]Fluoro-L-tryptophan ([ 18 F]FTRP), has been proposed as a functional analogue. There is no published method for the synthesis of L-[ 18 F]FTRP. We have therefore developed a synthesis of 5-fluoro-[β- 11 C]-L-tryptophan ([ 11 C]FTRP), based on the existing chemo-enzymatic method for [ 11 C]HTP and evaluated the potential usefulness of radiolabeled FTRP as a substitute for [ 11 C]HTP. Methods: The in vitro and in vivo behavior of [ 11 C]FTRP, including the dependence of key enzymes in the serotonergic metabolic pathway, was investigated in NET cell lines, NET xenograft carrying immunodeficient mice, normal rats and in non-human primate. [ 11 C]HTP was used for direct comparison. Results: Uptake of [ 11 C]FTRP in NET cell lines in vitro was mediated by enzymes involved in serotonin synthesis and metabolism, similar to [ 11 C]HTP. In vivo biodistribution, either in rodent or non-human primate, was not affected by selectively inhibiting enzymatic steps in the serotonergic metabolic pathway. Conclusion: [ 11 C]FTRP has in vitro biological function similar to that of [ 11 C]HTP. However, this function is not retained in vivo as shown by biodistribution and PET/CT studies. Radiolabeled FTRP is thus not likely to provide an advantage over [ 11 C]HTP in PET imaging in oncology, neurology or diabetes

  2. Bioenergy from sisal residues

    Energy Technology Data Exchange (ETDEWEB)

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    The main objectives of this report are: To analyse the bioenergy potential of the Tanzanian agro-industries, with special emphasis on the Sisal industry, the largest producer of agro-industrial residues in Tanzania; and to upgrade the human capacity and research potential of the Applied Microbiology Unit at the University of Dar es Salaam, in order to ensure a scientific and technological support for future operation and implementation of biogas facilities and anaerobic water treatment systems. The experimental work on sisal residues contains the following issues: Optimal reactor set-up and performance; Pre-treatment methods for treatment of fibre fraction in order to increase the methane yield; Evaluation of the requirement for nutrient addition; Evaluation of the potential for bioethanol production from sisal bulbs. The processing of sisal leaves into dry fibres (decortication) has traditionally been done by the wet processing method, which consumes considerable quantities of water and produces large quantities of waste water. The Tanzania Sisal Authority (TSA) is now developing a dry decortication method, which consumes less water and produces a waste product with 12-15% TS, which is feasible for treatment in CSTR systems (Continously Stirred Tank Reactors). (EG)

  3. Peroxyl radical- and photo-oxidation of glucose 6- phosphate dehydrogenase generates cross-links and functional changes via oxidation of tyrosine and tryptophan residues

    DEFF Research Database (Denmark)

    Leinisch, Fabian; Mariotti, Michele; Rykær, Martin

    2017-01-01

    indicate that pathophysiological processes and multiple human diseases are associated with the accumulation of damaged proteins. In this study we investigated the mechanisms and consequences of exposure of the key metabolic enzyme glucose-6-phosphate dehydrogenase (G6PDH) to peroxyl radicals (ROO...

  4. Stepwise O-Atom Transfer in Heme-Based Tryptophan Dioxygenase: Role of Substrate Ammonium in Epoxide Ring Opening.

    Science.gov (United States)

    Shin, Inchul; Ambler, Brett R; Wherritt, Daniel; Griffith, Wendell P; Maldonado, Amanda C; Altman, Ryan A; Liu, Aimin

    2018-03-28

    Heme-based tryptophan dioxygenases are established immunosuppressive metalloproteins with significant biomedical interest. Here, we synthesized two mechanistic probes to specifically test if the α-amino group of the substrate directly participates in a critical step of the O atom transfer during catalysis in human tryptophan 2,3-dioxygenase (TDO). Substitution of the nitrogen atom of the substrate to a carbon (probe 1) or oxygen (probe 2) slowed the catalytic step following the first O atom transfer such that transferring the second O atom becomes less likely to occur, although the dioxygenated products were observed with both probes. A monooxygenated product was also produced from probe 2 in a significant quantity. Analysis of this new product by HPLC coupled UV-vis spectroscopy, high-resolution mass spectrometry, 1 H NMR, 13 C NMR, HSQC, HMBC, and infrared (IR) spectroscopies concluded that this monooxygenated product is a furoindoline compound derived from an unstable epoxyindole intermediate. These results prove that small molecules can manipulate the stepwise O atom transfer reaction of TDO and provide a showcase for a tunable mechanism by synthetic compounds. The product analysis results corroborate the presence of a substrate-based epoxyindole intermediate during catalysis and provide the first substantial experimental evidence for the involvement of the substrate α-amino group in the epoxide ring-opening step during catalysis. This combined synthetic, biochemical, and biophysical study establishes the catalytic role of the α-amino group of the substrate during the O atom transfer reactions and thus represents a substantial advance to the mechanistic comprehension of the heme-based tryptophan dioxygenases.

  5. Interaction between 5-HTTLPR genotype and cognitive stress vulnerability on sleep quality: effects of sub-chronic tryptophan administration.

    Science.gov (United States)

    van Dalfsen, Jens H; Markus, C Rob

    2015-02-02

    Abundant evidence suggests that allelic variation in the serotonin transporter-linked polymorphic region (5-HTTLPR) influences susceptibility to stress and its affective consequences due to brain serotonergic vulnerability. Based on recent assumptions, the present study examined whether the 5-HTTLPR genotype may also interact with a vulnerability to chronic stress experience (conceptualized by trait neuroticism) in order to influence sleep quality and, additionally, whether this is influenced by brain serotonergic manipulations. In a well-balanced experimental design, homozygous S-allele (n = 57) and L-allele (n = 54) genotypes with high and low chronic stress vulnerability (neuroticism) were first assessed for general past sleep quality during a month before onset of the experiment. Then subjects were assessed for sleep quality following 7 days of tryptophan (3.0g/day) or placebo intake. Although high neuroticism was significantly related to a higher frequency of stressful life events and daily hassles, it did not interact with the 5-HTTLPR genotype on general past sleep quality. However, as expected, a 7 day period of tryptophan administration was exclusively associated with better sleep quality scores in the S'/S' genotype with high trait neuroticism. Current findings suggest that 5-HTTLPR does not directly interact with stress vulnerability in order to influence sleep quality. Instead, based on current and previous findings, it is suggested that the S'/S' 5-HTTLPR genotype promotes the risk for stress-related sleep disturbances because of an increased susceptibility to the depressogenic consequences of stress. Accordingly, by way of reducing depressive symptomatology, tryptophan augmentation may particularly improve sleep quality in stress-vulnerable individuals carrying the 5-HTTLPR S-allele. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  6. Depressive disorder and gastrointestinal dysfunction after myocardial infarct are associated with abnormal tryptophan-5-hydroxytryptamine metabolism in rats.

    Science.gov (United States)

    Lu, Xiaofang; Wang, Yuefen; Liu, Chunyan; Wang, Yangang

    2017-01-01

    In this study, we investigated the relationship between tryptophan-5-hydroxytryptamine metabolism, depressive disorder, and gastrointestinal dysfunction in rats after myocardial infarction. Our goal was to elucidate the physiopathologic bases of somatic/psychiatric depression symptoms after myocardial infarction. A myocardial infarction model was established by permanent occlusion of the left anterior descending coronary artery. Depression-like behavior was evaluated using the sucrose preference test, open field test, and forced swim test. Gastric retention and intestinal transit were detected using the carbon powder labeling method. Immunohistochemical staining was used to detect indoleamine 2,3-dioxygenase expression in the hippocampus and ileum. High-performance liquid chromatography with fluorescence and ultraviolet detection determined the levels of 5-hydroxytryptamine, its precursor tryptophan, and its metabolite 5-hydroxyindoleacetic acid in the hippocampus, distal ileum, and peripheral blood. All data were analyzed using one-way analyses of variance. Three weeks after arterial occlusion, rats in the model group began to exhibit depression-like symptoms. For example, the rate of sucrose consumption was reduced, the total and central distance traveled in the open field test were reduced, and immobility time was increased, while swimming, struggling and latency to immobility were decreased in the forced swim test. Moreover, the gastric retention rate and gastrointestinal transit rate were increased in the model group. Expression of indoleamine 2,3-dioxygenase was increased in the hippocampus and ileum, whereas 5-hydroxytryptamine metabolism was decreased, resulting in lower 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels in the hippocampus and higher levels in the ileum. Depressive disorder and gastrointestinal dysfunction after myocardial infarction involve abnormal tryptophan-5-hydroxytryptamine metabolism, which may explain the somatic, cognitive

  7. Depressive disorder and gastrointestinal dysfunction after myocardial infarct are associated with abnormal tryptophan-5-hydroxytryptamine metabolism in rats.

    Directory of Open Access Journals (Sweden)

    Xiaofang Lu

    Full Text Available In this study, we investigated the relationship between tryptophan-5-hydroxytryptamine metabolism, depressive disorder, and gastrointestinal dysfunction in rats after myocardial infarction. Our goal was to elucidate the physiopathologic bases of somatic/psychiatric depression symptoms after myocardial infarction. A myocardial infarction model was established by permanent occlusion of the left anterior descending coronary artery. Depression-like behavior was evaluated using the sucrose preference test, open field test, and forced swim test. Gastric retention and intestinal transit were detected using the carbon powder labeling method. Immunohistochemical staining was used to detect indoleamine 2,3-dioxygenase expression in the hippocampus and ileum. High-performance liquid chromatography with fluorescence and ultraviolet detection determined the levels of 5-hydroxytryptamine, its precursor tryptophan, and its metabolite 5-hydroxyindoleacetic acid in the hippocampus, distal ileum, and peripheral blood. All data were analyzed using one-way analyses of variance. Three weeks after arterial occlusion, rats in the model group began to exhibit depression-like symptoms. For example, the rate of sucrose consumption was reduced, the total and central distance traveled in the open field test were reduced, and immobility time was increased, while swimming, struggling and latency to immobility were decreased in the forced swim test. Moreover, the gastric retention rate and gastrointestinal transit rate were increased in the model group. Expression of indoleamine 2,3-dioxygenase was increased in the hippocampus and ileum, whereas 5-hydroxytryptamine metabolism was decreased, resulting in lower 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels in the hippocampus and higher levels in the ileum. Depressive disorder and gastrointestinal dysfunction after myocardial infarction involve abnormal tryptophan-5-hydroxytryptamine metabolism, which may explain the

  8. Inactivation of cellular caspases by peptide-derived tryptophan and tyrosine peroxides

    DEFF Research Database (Denmark)

    Hampton, Mark B; Morgan, Philip E; Davies, Michael Jonathan

    2002-01-01

    Peroxides generated on peptides and proteins within cells, as a result of radical attack or reaction with singlet oxygen, are longer-lived than H(2)O(2) due to their poor removal by protective enzymes. These peroxides readily oxidize cysteine residues and can inactivate thiol-dependent enzymes. W...

  9. THE EFFECTS OF GLYCATION ON THE BINDING OF HUMAN SERUM ALBUMIN TO WARFARIN AND L-TRYPTOPHAN

    OpenAIRE

    Joseph, K.S.; Hage, David S.

    2010-01-01

    Diabetes leads to elevated levels of glucose in blood which, in turn, can lead to the non-enzymatic glycation of serum proteins such as human serum albumin (HSA). It has been suggested that this increase in glycation can alter the ability of HSA to bind to drugs and other small solutes. This study used high-performance affinity chromatography (HPAC) to see if there is any significant change related to glycation in the binding of HSA to warfarin and L-tryptophan, which are often used as probe ...

  10. Characterization of 5-(2- 18F-fluoroethoxy)-L-tryptophan for PET imaging of the pancreas

    OpenAIRE

    Abbas, Ahmed; Beamish, Christine; McGirr, Rebecca; Demarco, John; Cockburn, Neil; Krokowski, Dawid; Lee, Ting-Yim; Kovacs, Michael; Hatzoglou, Maria; Dhanvantari, Savita

    2016-01-01

    Purpose: In diabetes, pancreatic beta cell mass declines significantly prior to onset of fasting hyperglycemia. This decline may be due to endoplasmic reticulum (ER) stress, and the system L amino acid transporter LAT1 may be a biomarker of this process. In this study, we used 5-(2- 18F-fluoroethoxy)-L-tryptophan ( 18F-L-FEHTP) to target LAT1 as a potential biomarker of beta cell function in diabetes. Procedures: Uptake of 18F-L-FEHTP was determined in wild-type C57BL/6 mice by ex vivo biodis...

  11. The GPR139 reference agonists 1a and 7c, and tryptophan and phenylalanine share a common binding site

    DEFF Research Database (Denmark)

    Shehata, Mohamed A.; Jensen, Anne Cathrine Nøhr; Jespers, Willem

    2017-01-01

    for GPR139. Two series published by Shi et al. and Dvorak et al. included agonists 1a and 7c respectively, with potencies in the ten-nanomolar range. Furthermore, Isberg et al. and Liu et al. have previously shown that tryptophan (Trp) and phenylalanine (Phe) can activate GPR139 in the hundred...... important for the activation of GPR139 as predicted by the receptor model. The initial ligand-receptor complex was optimized through free energy perturbation simulations, generating a refined GPR139 model in agreement with experimental data. In summary, the GPR139 reference surrogate agonists 1a and 7c...

  12. Uptake in the pancreatic islets of nicotimamide, nicotinic acid and tryptophan and their ability to prevent streptozotocin diabetes in mice

    Energy Technology Data Exchange (ETDEWEB)

    Tjaelve, H; Wilander, E [Uppsala Univ. (Sweden)

    1976-01-01

    The uptake of the nicotinamide adenine dinucleotide (NAD)-precursors nicotinamide, nicotinic acid and tryptophan in the pancreatic islets of mice was studied by use of autoradio-graphical methods. The ability of these substances to prevent streptozotocin diabetes was studied in the same species. It was found that only nicotinamide was strongly accumulated in the pancreatic islets and nicotinamide was also the only NAD-precursor which protected against the streptozotocin diabetes. Apparently there is a relationship between the ability of the NAD-precursors to be taken up in the pancreatic islets and their ability to prevent streptozotocin diabetes.

  13. Geochemical Testing And Model Development - Residual Tank Waste Test Plan

    International Nuclear Information System (INIS)

    Cantrell, K.J.; Connelly, M.P.

    2010-01-01

    This Test Plan describes the testing and chemical analyses release rate studies on tank residual samples collected following the retrieval of waste from the tank. This work will provide the data required to develop a contaminant release model for the tank residuals from both sludge and salt cake single-shell tanks. The data are intended for use in the long-term performance assessment and conceptual model development.

  14. Process for measuring residual stresses

    International Nuclear Information System (INIS)

    Elfinger, F.X.; Peiter, A.; Theiner, W.A.; Stuecker, E.

    1982-01-01

    No single process can at present solve all problems. The complete destructive processes only have a limited field of application, as the component cannot be reused. However, they are essential for the basic determination of stress distributions in the field of research and development. Destructive and non-destructive processes are mainly used if investigations have to be carried out on original components. With increasing component size, the part of destructive tests becomes smaller. The main applications are: quality assurance, testing of manufactured parts and characteristics of components. Among the non-destructive test procedures, X-raying has been developed most. It gives residual stresses on the surface and on surface layers near the edges. Further development is desirable - in assessment - in measuring techniques. Ultrasonic and magnetic crack detection processes are at present mainly used in research and development, and also in quality assurance. Because of the variable depth of penetration and the possibility of automation they are gaining in importance. (orig./RW) [de

  15. Ancient origin of the tryptophan operon and the dynamics of evolutionary change.

    Science.gov (United States)

    Xie, Gary; Keyhani, Nemat O; Bonner, Carol A; Jensen, Roy A

    2003-09-01

    The seven conserved enzymatic domains required for tryptophan (Trp) biosynthesis are encoded in seven genetic regions that are organized differently (whole-pathway operons, multiple partial-pathway operons, and dispersed genes) in prokaryotes. A comparative bioinformatics evaluation of the conservation and organization of the genes of Trp biosynthesis in prokaryotic operons should serve as an excellent model for assessing the feasibility of predicting the evolutionary histories of genes and operons associated with other biochemical pathways. These comparisons should provide a better understanding of possible explanations for differences in operon organization in different organisms at a genomics level. These analyses may also permit identification of some of the prevailing forces that dictated specific gene rearrangements during the course of evolution. Operons concerned with Trp biosynthesis in prokaryotes have been in a dynamic state of flux. Analysis of closely related organisms among the Bacteria at various phylogenetic nodes reveals many examples of operon scission, gene dispersal, gene fusion, gene scrambling, and gene loss from which the direction of evolutionary events can be deduced. Two milestone evolutionary events have been mapped to the 16S rRNA tree of Bacteria, one splitting the operon in two, and the other rejoining it by gene fusion. The Archaea, though less resolved due to a lesser genome representation, appear to exhibit more gene scrambling than the Bacteria. The trp operon appears to have been an ancient innovation; it was already present in the common ancestor of Bacteria and Archaea. Although the operon has been subjected, even in recent times, to dynamic changes in gene rearrangement, the ancestral gene order can be deduced with confidence. The evolutionary history of the genes of the pathway is discernible in rough outline as a vertical line of descent, with events of lateral gene transfer or paralogy enriching the analysis as interesting

  16. The Relationships among Tryptophan, Kynurenine, Indoleamine 2,3-Dioxygenase, Depression, and Neuropsychological Performance.

    Science.gov (United States)

    Hestad, Knut A; Engedal, Knut; Whist, Jon E; Farup, Per G

    2017-01-01

    It has been suggested that the metabolic enzyme indoleamine 2,3-dioxygenase (IDO) is a biological mediator of inflammation related to the psychopathology of depression, with a Kynurenine (KYN) increase in the Tryptophan (TRP) metabolic pathway, resulting in reduced Serotonin. In this study, we examined KYN, TRP, and the ratio of KYN to TRP concentrations × 10 3 (KT Ratio) in serum and cerebrospinal fluid (CSF) in (a) a group of depressed patients and (b) a control group of patients referred to a neurologic outpatient clinic for whom no specific diagnosis could be established. The KT Ratio is considered an index that represents IDO. The participants were examined with the Beck Depression Inventory II (BDI-II), the Montgomery Aasberg Depression Rating Scale (MADRS), and a neuropsychological test battery. We found no significant differences between the two study groups with respect to TRP, KYN, or KT Ratio in serum or CSF. Differences in neuropsychological performance between the two patient groups could be seen in the following tests: Animal Fluency, Digit Symbol, the DKEFS Color-Interference Test (Naming Part), Trail Making Test A and B, and the Grooved Pegboard Non-dominant Hand. KYN in serum correlated highly with KYN in CSF. KYN in serum correlated significantly with both age and gender. When analyzing males and females separately, we found that women had a lower level of TRP in both serum (Mann-Whitney U -test: TRP in Serum; p = 0.001) and CSF (Mann-Whitney U -test: TRP in CSF; p = 0.003). Women had a lower level of KYN in serum ( p = 0.029) than men did. Age was positively associated with KYN. KYN in CSF correlated only with age, however; there were no gender differences. No significant relationship was seen between BDI-II and MADRS on the one hand, and KYN and TRP on the other. KYN in CSF as the KT Ratio in both serum and CSF was associated with neuropsychological performance. Thus, we suggest that KYN and KT Ratio are related more strongly to

  17. The Relationships among Tryptophan, Kynurenine, Indoleamine 2,3-Dioxygenase, Depression, and Neuropsychological Performance

    Directory of Open Access Journals (Sweden)

    Knut A. Hestad

    2017-10-01

    Full Text Available It has been suggested that the metabolic enzyme indoleamine 2,3-dioxygenase (IDO is a biological mediator of inflammation related to the psychopathology of depression, with a Kynurenine (KYN increase in the Tryptophan (TRP metabolic pathway, resulting in reduced Serotonin. In this study, we examined KYN, TRP, and the ratio of KYN to TRP concentrations × 103 (KT Ratio in serum and cerebrospinal fluid (CSF in (a a group of depressed patients and (b a control group of patients referred to a neurologic outpatient clinic for whom no specific diagnosis could be established. The KT Ratio is considered an index that represents IDO. The participants were examined with the Beck Depression Inventory II (BDI-II, the Montgomery Aasberg Depression Rating Scale (MADRS, and a neuropsychological test battery. We found no significant differences between the two study groups with respect to TRP, KYN, or KT Ratio in serum or CSF. Differences in neuropsychological performance between the two patient groups could be seen in the following tests: Animal Fluency, Digit Symbol, the DKEFS Color-Interference Test (Naming Part, Trail Making Test A and B, and the Grooved Pegboard Non-dominant Hand. KYN in serum correlated highly with KYN in CSF. KYN in serum correlated significantly with both age and gender. When analyzing males and females separately, we found that women had a lower level of TRP in both serum (Mann–Whitney U-test: TRP in Serum; p = 0.001 and CSF (Mann–Whitney U-test: TRP in CSF; p = 0.003. Women had a lower level of KYN in serum (p = 0.029 than men did. Age was positively associated with KYN. KYN in CSF correlated only with age, however; there were no gender differences. No significant relationship was seen between BDI-II and MADRS on the one hand, and KYN and TRP on the other. KYN in CSF as the KT Ratio in both serum and CSF was associated with neuropsychological performance. Thus, we suggest that KYN and KT Ratio are related more strongly to

  18. Ancient Origin of the Tryptophan Operon and the Dynamics of Evolutionary Change†

    Science.gov (United States)

    Xie, Gary; Keyhani, Nemat O.; Bonner; Jensen, Roy A.

    2003-01-01

    The seven conserved enzymatic domains required for tryptophan (Trp) biosynthesis are encoded in seven genetic regions that are organized differently (whole-pathway operons, multiple partial-pathway operons, and dispersed genes) in prokaryotes. A comparative bioinformatics evaluation of the conservation and organization of the genes of Trp biosynthesis in prokaryotic operons should serve as an excellent model for assessing the feasibility of predicting the evolutionary histories of genes and operons associated with other biochemical pathways. These comparisons should provide a better understanding of possible explanations for differences in operon organization in different organisms at a genomics level. These analyses may also permit identification of some of the prevailing forces that dictated specific gene rearrangements during the course of evolution. Operons concerned with Trp biosynthesis in prokaryotes have been in a dynamic state of flux. Analysis of closely related organisms among the Bacteria at various phylogenetic nodes reveals many examples of operon scission, gene dispersal, gene fusion, gene scrambling, and gene loss from which the direction of evolutionary events can be deduced. Two milestone evolutionary events have been mapped to the 16S rRNA tree of Bacteria, one splitting the operon in two, and the other rejoining it by gene fusion. The Archaea, though less resolved due to a lesser genome representation, appear to exhibit more gene scrambling than the Bacteria. The trp operon appears to have been an ancient innovation; it was already present in the common ancestor of Bacteria and Archaea. Although the operon has been subjected, even in recent times, to dynamic changes in gene rearrangement, the ancestral gene order can be deduced with confidence. The evolutionary history of the genes of the pathway is discernible in rough outline as a vertical line of descent, with events of lateral gene transfer or paralogy enriching the analysis as interesting

  19. Formation of intermediate cementum. III: 3H-tryptophan and 3H-proline uptake into the epithelial root sheath of Hertwig in vitro

    International Nuclear Information System (INIS)

    Lindskog, S.; Hammarstroem, L.

    1982-01-01

    The intermediate cementum is a narrow, mineralized tissue between the cementum and dentin. Recent studies have shown that this tissue is mineralized by the epithelial root sheath in a way similar to the mineralization of the innermost layer of aprismatic enamel. In the present investigation uptake of proline and tryptophan into the epithelial root sheath was studied with autoradiography. Tryptophan is an amino acid that is incorporated into enamel matrix but not into collagen. Tryptophan uptake was significant in the whole epithelial root sheath, but not into the odontoblasts or predentin. Proline was incorporated into the predentin while the root sheath was unlabeled. This indicated that the matrix of the intermediate cementum was formed by the epithelial root sheath of Hertwig, and that this matrix was a noncollagenous matrix possibly of the same nature as enamel matrix

  20. Residual Stress Analysis Based on Acoustic and Optical Methods

    Directory of Open Access Journals (Sweden)

    Sanichiro Yoshida

    2016-02-01

    Full Text Available Co-application of acoustoelasticity and optical interferometry to residual stress analysis is discussed. The underlying idea is to combine the advantages of both methods. Acoustoelasticity is capable of evaluating a residual stress absolutely but it is a single point measurement. Optical interferometry is able to measure deformation yielding two-dimensional, full-field data, but it is not suitable for absolute evaluation of residual stresses. By theoretically relating the deformation data to residual stresses, and calibrating it with absolute residual stress evaluated at a reference point, it is possible to measure residual stresses quantitatively, nondestructively and two-dimensionally. The feasibility of the idea has been tested with a butt-jointed dissimilar plate specimen. A steel plate 18.5 mm wide, 50 mm long and 3.37 mm thick is braze-jointed to a cemented carbide plate of the same dimension along the 18.5 mm-side. Acoustoelasticity evaluates the elastic modulus at reference points via acoustic velocity measurement. A tensile load is applied to the specimen at a constant pulling rate in a stress range substantially lower than the yield stress. Optical interferometry measures the resulting acceleration field. Based on the theory of harmonic oscillation, the acceleration field is correlated to compressive and tensile residual stresses qualitatively. The acoustic and optical results show reasonable agreement in the compressive and tensile residual stresses, indicating the feasibility of the idea.

  1. Immobilization of acid digestion residue

    International Nuclear Information System (INIS)

    Greenhalgh, W.O.; Allen, C.R.

    1983-01-01

    Acid digestion treatment of nuclear waste is similar to incineration processes and results in the bulk of the waste being reduced in volume and weight to some residual solids termed residue. The residue is composed of various dispersible solid materials and typically contains the resultant radioactivity from the waste. This report describes the immobilization of the residue in portland cement, borosilicate glass, and some other waste forms. Diagrams showing the cement and glass virtification parameters are included in the report as well as process steps and candidate waste product forms. Cement immobilization is simplest and probably least expensive; glass vitrification exhibits the best overall volume reduction ratio

  2. Radioimmunoassay for 6-D-tryptophan analog of luteinizing hormone-releasing hormone: measurement of serum levels after administration of long-acting microcapsule formulations

    International Nuclear Information System (INIS)

    Mason-Garcia, M.; Vigh, S.; Comaru-Schally, A.M.; Redding, T.W.; Somogyvari-Vigh, A.; Horvath, J.; Schally, A.V.

    1985-01-01

    A sensitive and specific radioimmunoassay for [6-D-tryptophan]luteinizing hormone-releasing hormone ([D-Trp 6 ]LH-RH) was developed and used for following the rate of liberation of [D-Trp 6 ]LH-RH from a long-acting delivery systems based on a microcapsule formulation. Rabbit antibodies were generated against [D-Trp 6 ]LH-RH conjugated to bovine serum albumin with glutaraldehyde. Crossreactivity with LH-RH was less than 1%; there was no significant cross-reactivity with other peptides. The minimal detectable dose of [D-Trp 6 ]LH-RH was 2 pg per tube. In tra- and interassay coefficients of variation were 8% and 10%, respectively. The radioimmunoassay was suitable for direct determination of [D-Trp 6 ]LH-RH in serum, permitting the study of blood levels of the analog after single injections into normal men and after one-a-month administration of microcapsules to rats. In men, 90 min after subcutaneous injection of 250 μg of the peptide, serum [D-Trp 6 ]LH-RH rose to 6-12 ng/ml. Luteinizing hormone was increased 90 min and 24 hr after the administration of the analog. Several batches of microcapsules were tested in rats and the rate of release of [D-Trp 6 ]LH-RH was followed. The improved batch of microcapsules of [D-Trp 6 ]LH-RH increased serum concentrations of the analog for 30 days or longer after intramuscular injection

  3. Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

    Science.gov (United States)

    Rutherford, R.; Gallois, P.; Masson, P. H.

    1998-01-01

    Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

  4. Kynurenic Acid: The Janus-Faced Role of an Immunomodulatory Tryptophan Metabolite and Its Link to Pathological Conditions

    Directory of Open Access Journals (Sweden)

    Elisa Wirthgen

    2018-01-01

    Full Text Available Tryptophan metabolites are known to participate in the regulation of many cells of the immune system and are involved in various immune-mediated diseases and disorders. Kynurenic acid (KYNA is a product of one branch of the kynurenine pathway of tryptophan metabolism. The influence of KYNA on important neurophysiological and neuropathological processes has been comprehensively documented. In recent years, the link of KYNA to the immune system, inflammation, and cancer has become more apparent. Given this connection, the anti-inflammatory and immunosuppressive functions of KYNA are of particular interest. These characteristics might allow KYNA to act as a “double-edged sword.” The metabolite contributes to both the resolution of inflammation and the establishment of an immunosuppressive environment, which, for instance, allows for tumor immune escape. Our review provides a comprehensive update of the significant biological functions of KYNA and focuses on its immunomodulatory properties by signaling via G-protein-coupled receptor 35 (GPR35- and aryl hydrocarbon receptor-mediated pathways. Furthermore, we discuss the role of KYNA–GPR35 interaction and microbiota associated KYNA metabolism for gut homeostasis.

  5. Experimentally calibrated computational chemistry of tryptophan hydroxylase: Trans influence, hydrogen-bonding, and 18-electron rule govern O-2-activation

    DEFF Research Database (Denmark)

    Haahr, Lærke Tvedebrink; Kepp, Kasper Planeta; Boesen, Jane

    2010-01-01

    with the experimental value (0.25 mm/s) which we propose as the structure of the hydroxylating intermediate, with the tryptophan substrate well located for further reaction 3.5 Å from the ferryl group. Based on the optimized transition states, the activation barriers for the two paths (glu and his) are similar, so......Insight into the nature of oxygen activation in tryptophan hydroxylase has been obtained from density functional computations. Conformations of O2-bound intermediates have been studied with oxygen trans to glutamate and histidine, respectively. An O2-adduct with O2 trans to histidine (Ohis...... towards the cofactor and a more activated O–O bond (1.33 Å) than in Oglu (1.30 Å). It is shown that the cofactor can hydrogen bond to O2 and activate the O–O bond further (from 1.33 to 1.38 Å). The Ohis intermediate leads to a ferryl intermediate (Fhis) with an isomer shift of 0.34 mm/s, also consistent...

  6. Lactobacillus johnsonii inhibits indoleamine 2,3-dioxygenase and alters tryptophan metabolite levels in BioBreeding rats.

    Science.gov (United States)

    Valladares, Ricardo; Bojilova, Lora; Potts, Anastasia H; Cameron, Evan; Gardner, Christopher; Lorca, Graciela; Gonzalez, Claudio F

    2013-04-01

    In our previous work, we found that feeding Lactobacillus johnsonii to BioBreeding diabetes-prone (BBDP) rats decreased the incidence of diabetes development. The aim of this study was to investigate host pathways affected by L. johnsonii, with specific focus on the rate-limiting enzyme of tryptophan catabolism, indoleamine 2,3-dioxygenase (IDO). Suspensions of L. johnsonii or an equal volume of vehicle were orally administered to BBDP rats. Tissue IDO was investigated using quantitative RT-PCR and Western blot, whereas tryptophan, kynurenine, and 5-hydroxytryptamine (5-HT) concentrations were quantified by HPLC and ELISA. IDO activity was also investigated using L. johnsonii culture cell-free supernatant (CFS) with affinity-purified IDO and HT-29 intestinal epithelial cells. L. johnsonii feeding resulted in a 17% reduction in serum kynurenine compared with that in vehicle-fed controls, correlating with a 1.4-fold elevation in 5-HT levels. H₂O₂ produced by L. johnsonii abolished IDO activity in vitro, and L. johnsonii feeding resulted in a 3.9-fold increase in ileum lumen H₂O₂. L. johnsonii CFS significantly reduced IDO activity in HT-29 intestinal epithelial cells (47% reduction) compared with that in vehicle-treated controls, an effect abolished by catalase treatment. These data support the role of H₂O₂ in commensal bacteria-host interactions and highlight the influence of commensal bacteria-derived H₂O₂ on host physiology.

  7. Effect of acute tryptophan depletion on emotions in individuals with personal and family history of depression following a mood induction.

    Science.gov (United States)

    Altman, Sarah E; Shankman, Stewart A; Spring, Bonnie

    2010-08-01

    Acute tryptophan depletion (ATD) has shown depletion-specific increases in depressed mood and overall depressive symptoms, especially in those with a family history and in remitted patients. However, its effect on a broad range of emotions beyond depressed mood has been inconsistent, and studies have rarely employed a negative mood induction. The present double-blind study administered tryptophan-depleted and taste-matched placebo challenge drinks to individuals with a past diagnosis and family history of depression (i.e. depression-vulnerable subjects) and controls in order to investigate the effect of ATD on positive affect, anxiety, anger and depressed mood following a negative mood induction. Certain aspects of positive affect decreased due to ATD in the depression vulnerables but not in the controls. No differential effects were found on depressed mood and anxiety. A stress-induced blunted hedonic capacity may increase vulnerability to ATD and may be a core emotional abnormality in depression. Additionally, serotonin may have a stronger influence on positive affect than on other depression-related emotions during periods of stress. (c) 2010 S. Karger AG, Basel.

  8. Radiosynthesis of 1-[{sup 18}F]fluoroethyl-L-tryptophan as a novel potential amino acid PET tracer

    Energy Technology Data Exchange (ETDEWEB)

    Sun Ting, E-mail: beibeisun2008@163.com [Department of Cardiac Function, Shanghai Ninth People' s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Tang Ganghua, E-mail: gtang0224@yahoo.com.cn [Department of Nuclear Medicine, the first affiliated hospital, SunYat-Sen University, Guangzhou 510080 (China); Tian Hua [State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032 (China); Wang Xiaoyan [Department of Nuclear Medicine, the first affiliated hospital, SunYat-Sen University, Guangzhou 510080 (China); Chen Xianghua [Department of Cardiac Function, Shanghai Ninth People' s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Chen Zhifeng [Department of Nuclear Medicine, the first affiliated hospital, SunYat-Sen University, Guangzhou 510080 (China); Wang Shihchen [Department of Nuclear Medicine, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, 1 Shuaifuyuan Wangfujing Beijing 100730 (China)

    2012-04-15

    {sup 18}F labeled natural amino acids have been introduced as promising tumor imaging agents. A novel [{sup 18}F]fluoro amino acid analog 1-[{sup 18}F]fluoroethyl-L-tryptophan (1-[{sup 18}F]FETrp) was designed and synthesized by a two-pot three-step procedure, including the synthesis of 1-[{sup 18}F]fluoro-2- (tosyloxy)ethane, the [{sup 18}F]fluoroethylation of the precursor N-Boc-L-tryptophan ethyl ester and following the deprotection of the tert-butoxycarbonyl and ethyl ester protecting groups. 1-[{sup 18}F]FETrp was resulted in 0.9{+-}0.2% (n=5) radiochemical yields (no decay corrected) by HPLC purification, within a total synthesis time of 65 min. The radiochemical purity of 1-[{sup 18}F]FETrp was 95-97%. The radiosynthetic method needs to be further optimized to get a satisfying radiochemical yield. - Highlights: Black-Right-Pointing-Pointer We designed and synthesized the novel amino acid analog 1-[{sup 19}F]FETrp. Black-Right-Pointing-Pointer We radiosynthesized 1-[{sup 18}F]FETrp using the two-pot three-step procedure. Black-Right-Pointing-Pointer The total synthesis time was 65 min and the yield was very low. Black-Right-Pointing-Pointer The synthetic strategy via [{sup 18}F]FCH{sub 2}CH{sub 2}OTs needs to be optimized or changed.

  9. The role of serotonin in personality inference: tryptophan depletion impairs the identification of neuroticism in the face.

    Science.gov (United States)

    Ward, Robert; Sreenivas, Shubha; Read, Judi; Saunders, Kate E A; Rogers, Robert D

    2017-07-01

    Serotonergic mechanisms mediate the expression of personality traits (such as impulsivity, aggression and anxiety) that are linked to vulnerability to psychological illnesses, and modulate the identification of emotional expressions in the face as well as learning about broader classes of appetitive and aversive signals. Faces with neutral expressions signal a variety of socially relevant information, such that inferences about the big five personality traits, including Neuroticism, Extraversion and Agreeableness, can be accurately made on the basis of emotionally neutral facial photographs. Given the close link between Neuroticism and psychological distress, we investigated the effects of diminished central serotonin activity (achieved by tryptophan depletion) upon the accuracy of 52 healthy (non-clinical) adults' discriminations of personality from facial characteristics. All participants were able to discriminate reliably four of the big five traits. However, the tryptophan-depleted participants were specifically less accurate in discriminating Neuroticism than the matched non-depleted participants. These data suggest that central serotonin activity modulates the identification of not only negative facial emotional expression but also a broader class of signals about personality characteristics linked to psychological distress.

  10. l-Tryptophan-capped carbon quantum dots for the sensitive and selective fluorescence detection of mercury ion in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Xuejuan; Li, Shifeng; Zhuang, Lulu; Tang, Jiaoning, E-mail: tjn@szu.edu.cn [Shenzhen University, Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering (China)

    2016-07-15

    l-Tryptophan-capped carbon quantum dots (l-CQDs) were facilely synthesized through “green” methodology, and the obtained material was utilized as a sensitive and selective fluorescence sensor for mercury ion (Hg{sup 2+}) in pure aqueous solutions. Carboxyl-functionalized CQDs were first green synthesized by a one-step hydrothermal route, and l-tryptophan was then attached to CQDs via direct surface condensation reaction in aqueous solution at room temperature. The as-synthesized l-CQDs had an average size of ca. 5 nm with a good dispersity in water, and exhibited a favorable selectivity for Hg{sup 2+} ions over a range of other common metal cations in aqueous solution (10 mM PBS buffer, pH 6.0). Upon the addition of Hg{sup 2+}, a complete fluorescence quenching (ON–OFF switching) of l-CQDs was evident from the fluorescence titration experiment, and the fluorescence detection limit of Hg{sup 2+} was calculated to be 11 nM, which indicated that the obtained environmentally friendly l-CQDs had sensitive detection capacity for Hg{sup 2+} in aqueous solution.

  11. A Better Understanding of Protein Structure and Function by the Synthesis and Incorporation of Selenium- and Tellurium Containing Tryptophan Analogs

    Energy Technology Data Exchange (ETDEWEB)

    Helmey, Sherif Samir [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Belmont Univ., Nashville, TN (United States). Dept. of Chemistry and Physics; Rice, Ambrose Eugene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Belmont Univ., Nashville, TN (United States). Dept. of Chemistry and Physics; Hatch, Duane Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Belmont Univ., Nashville, TN (United States). Dept. of Chemistry and Physics; Silks, Louis A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Marti-Arbona, Ricardo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division

    2016-08-17

    Unnatural heavy metal-containing amino acid analogs have shown to be very important in the analysis of protein structure, using methods such as X-ray crystallography, mass spectroscopy, and NMR spectroscopy. Synthesis and incorporation of selenium-containing methionine analogs has already been shown in the literature however with some drawbacks due to toxicity to host organisms. Thus synthesis of heavy metal tryptophan analogs should prove to be more effective since the amino acid tryptophan is naturally less abundant in many proteins. For example, bioincorporation of β-seleno[3,2-b]pyrrolyl-L-alanine ([4,5]SeTrp) and β-selenolo[2,3-b]pyrrolyl-L-alanine ([6,7]SeTrp) has been shown in the following proteins without structural or catalytic perturbations: human annexin V, barstar, and dihydrofolate reductase. The reported synthesis of these Se-containing analogs is currently not efficient for commercial purposes. Thus a more efficient, concise, high-yield synthesis of selenotryptophan, as well as the corresponding, tellurotryptophan, will be necessary for wide spread use of these unnatural amino acid analogs. This research will highlight our progress towards a synthetic route of both [6,7]SeTrp and [6,7]TeTrp, which ultimately will be used to study the effect on the catalytic activity of Lignin Peroxidase (LiP).

  12. Evaluation of residue-residue contact predictions in CASP9

    KAUST Repository

    Monastyrskyy, Bohdan

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures being the precision in recognizing contacts and the difference between the distribution of distances in the subset of predicted contact pairs versus all pairs of residues in the structure. The emphasis is placed on the prediction of long-range contacts (i.e., contacts between residues separated by at least 24 residues along sequence) in target proteins that cannot be easily modeled by homology. Although there is considerable activity in the field, the current analysis reports no discernable progress since CASP8.

  13. Landfilling of waste incineration residues

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Cai, Zuansi

    2002-01-01

    Residues from waste incineration are bottom ashes and air-pollution-control (APC) residues including fly ashes. The leaching of heavy metals and salts from the ashes is substantial and a wide spectrum of leaching tests and corresponding criteria have been introduced to regulate the landfilling...

  14. Statistical inference on residual life

    CERN Document Server

    Jeong, Jong-Hyeon

    2014-01-01

    This is a monograph on the concept of residual life, which is an alternative summary measure of time-to-event data, or survival data. The mean residual life has been used for many years under the name of life expectancy, so it is a natural concept for summarizing survival or reliability data. It is also more interpretable than the popular hazard function, especially for communications between patients and physicians regarding the efficacy of a new drug in the medical field. This book reviews existing statistical methods to infer the residual life distribution. The review and comparison includes existing inference methods for mean and median, or quantile, residual life analysis through medical data examples. The concept of the residual life is also extended to competing risks analysis. The targeted audience includes biostatisticians, graduate students, and PhD (bio)statisticians. Knowledge in survival analysis at an introductory graduate level is advisable prior to reading this book.

  15. Role of an Absolutely Conserved Tryptophan Pair in the Extracellular Domain of Cys-Loop Receptors

    DEFF Research Database (Denmark)

    Braun, Nina; Lynagh, Timothy; Yu, Rilei

    2016-01-01

    Cys-loop receptors mediate fast synaptic transmission in the nervous system, and their dysfunction is associated with a number of diseases. While some sequence variability is essential to ensure specific recognition of a chemically diverse set of ligands, other parts of the underlying amino acid...... sequences show a high degree of conservation, possibly to preserve the overall structural fold across the protein family. In this study, we focus on the only two absolutely conserved residues across the Cys-loop receptor family, two Trp side chains in the WXD motif of Loop D and in the WXPD motif of Loop A...

  16. Radiosynthesis and biological evaluation of 5-(3-[18F]Fluoropropyloxy)-L-tryptophan for tumor PET imaging

    International Nuclear Information System (INIS)

    He, Shanzhen; Tang, Ganghua; Hu, Kongzhen; Wang, Hongliang; Wang, Shuxia; Huang, Tingting; Liang, Xiang; Tang, Xiaolan

    2013-01-01

    Introduction: [ 18 F]FDG PET has difficulty distinguishing tumor from inflammation in the clinic because of the same high uptake in nonmalignant and inflammatory tissue. In contrast, amino acid tracers do not accumulate in inflamed tissues and thus provide an excellent opportunity for their use in clinical cancer imaging. In this study, we developed a new amino acid tracer 5-(3-[ 18 F]Fluoropropyloxy)-L-tryptophan ([ 18 F]-L-FPTP) by two-step reactions and performed its biologic evaluation. Methods: [ 18 F]-L-FPTP was prepared by [ 18 F]fluoropropylation of 5-hydroxy-L-tryptophan disodium salt and purification on C18 cartridges. The biodistribution of [ 18 F]-L-FPTP was determined in normal mice and the incorporation of [ 18 F]-L-FPTP into tissue proteins was investigated. In vitro competitive inhibition experiments were performed with Hepa1-6 hepatoma cell lines. [ 18 F]-L-FPTP PET imaging was performed on tumor-bearing and inflammation mice and compared with [ 18 F]-L-FEHTP PET. Results: The overall uncorrected radiochemical yield of [ 18 F]-L-FPTP was 21.1 ± 4.4% with a synthesis time of 60 min, the radiochemical purity was more than 99%. Biodistribution studies demonstrate high uptake of [ 18 F]-L-FPTP in liver, kidney, pancreas, and blood at the early phase, and fast clearance in most tissues over the whole observed time. The uptake studies in Hepa1-6 cells suggest that [ 18 F]-L-FPTP is transported by the amino acid transport system B 0,+ , LAT2 and ASC. [ 18 F]-L-FPTP displays good stability and is not incorporated into proteins in vitro. PET imaging shows that [ 18 F]-L-FPTP can be a better potential PET tracer for differentiating tumor from inflammation than [ 18 F]FDG and 5-(3-[ 18 F]fluoroethyloxy)-L-tryptophan ([ 18 F]-L-FEHTP), with high [ 18 F]-L-FPTP uptake ratio (2.53) of tumor to inflammation at 60 min postinjection. Conclusions: Using [ 18 F]fluoropropyl derivatives as intermediates, the new tracer [ 18 F]-L-FPTP was achieved with good yield and

  17. Effects of dietary tryptophan and phenylalanine–tyrosine depletion on phasic alertness in healthy adults – A pilot study

    Directory of Open Access Journals (Sweden)

    Patricia Hildebrand

    2015-04-01

    Full Text Available Background: The synthesis of the neurotransmitters serotonin (5-HT and dopamine (DA in the brain can be directly altered by dietary manipulation of their relevant precursor amino acids (AA. There is evidence that altered serotonergic and dopaminergic neurotransmission are both associated with impaired attentional control. Specifically, phasic alertness is one specific aspect of attention that has been linked to changes in 5-HT and DA availability in different neurocircuitries related to attentional processes. The present study investigated the impact of short-term reductions in central nervous system 5-HT and DA synthesis, which was achieved by dietary depletion of the relevant precursor AA, on phasic alertness in healthy adult volunteers; body weight–adapted dietary tryptophan and phenylalanine–tyrosine depletion (PTD techniques were used. Methods: The study employed a double-blind between-subject design. Fifty healthy male and female subjects were allocated to three groups in a randomized and counterbalanced manner and received three different dietary challenge conditions: acute tryptophan depletion (ATD, for the depletion of 5-HT; N=16, PTD (for the depletion of DA; N=17, and a balanced AA load (BAL; N=17, which served as a control condition. Three hours after challenge intake (ATD/PTD/BAL, phasic alertness was assessed using a standardized test battery for attentional performance (TAP. Blood samples for AA level analyses were obtained at baseline and 360 min after the challenge intake. Results: Overall, there were no significant differences in phasic alertness for the different challenge conditions. Regarding PTD administration, a positive correlation between the reaction times and the DA-related depletion magnitude was detected via the lower plasma tyrosine levels and the slow reaction times of the first run of the task. In contrast, higher tryptophan concentrations were associated with slower reaction times in the fourth run of the

  18. Residual stress by repair welds

    International Nuclear Information System (INIS)

    Mochizuki, Masahito; Toyoda, Masao

    2003-01-01

    Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

  19. Niclosamide residues in milk and organs of lactating goats

    International Nuclear Information System (INIS)

    El Hindi, A.M.; Sidra, M.S.

    1986-01-01

    14 C-Niclosamide was administered to two groups of lactating goats at levels of 2ppm for five consecutive days and 10ppm as a single dose. Residues of the molluscicide in milk, if at all present, did not exceed 0.001 ppm at any time. About 50% of the administered activity was excreted in faeces, while 30% excreted through urine in animals surviving 6 days after withdrawal. The unchanged molluscicide is present only in relatively trace amounts. The highest residues in organs were found in the liver of both groups (0.01-0.04 ppm). From the results it could be concluded that absorbed niclosamide is completely metabolised and rapidly eliminated through urine, leaving little or no residues of the unchanged molluscicide. Little or no residues were detected in lean muscles and milk which are consumed by humans. There is no preferential deposition of the molluscicide or its metabolites in fat

  20. Profiling of tryptophan-related plasma indoles in patients with carcinoid tumors by automated, on-line, solid-phase extraction and HPLC with fluorescence detection

    NARCIS (Netherlands)

    Kema, IP; Meijer, WG; Meiborg, G; Ooms, B; Willemse, PHB; de Vries, EGE

    2001-01-01

    Background: Profiling of the plasma indoles tryptophan, 5-hydroxytryptophan (5-HTP), serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) is useful in the diagnosis and follow-up of patients with carcinoid tumors. We describe an automated method for the profiling of these indoles in protein-containing

  1. Influence of Hepatitis C Virus Sustained Virological Response on Immunosuppressive Tryptophan Catabolism in ART-Treated HIV/HCV Coinfected Patients

    NARCIS (Netherlands)

    Jenabian, Mohammad-Ali; Mehraj, Vikram; Costiniuk, Cecilia T.; Vyboh, Kishanda; Kema, Ido; Rollet, Kathleen; Ramirez, Robert Paulino; Klein, Marina B.; Routy, Jean-Pierre

    2016-01-01

    Background: We previously reported an association between tryptophan (Trp) catabolism and immune dysfunction in HIV monoinfection. Coinfection with HIV is associated with more rapid evolution of hepatitis C virus (HCV)-associated liver disease despite antiretroviral therapy (ART), possibly due to

  2. Association between A218C polymorphism of the tryptophan-hydroxylase-1 gene, harm avoidance and binge eating behavior in bulimia nervosa.

    Science.gov (United States)

    Monteleone, Palmiero; Tortorella, Alfonso; Martiadis, Vassilis; Serino, Ismene; Di Filippo, Carmela; Maj, Mario

    2007-06-21

    Genes involved in serotonin transmission are likely involved in the biological predisposition to bulimia nervosa. We investigated whether the A218C polymorphism of the tryptophan-hydroxylase-1 gene was associated to bulimia nervosa and/or to some phenotypic aspects of the disorder. One hundred eighty Caucasian women (91 patients with bulimia nervosa and 89 healthy controls) were enrolled into the study. They underwent a blood sample collection for A218C polymorphism of the tryptophan-hydroxylase-1 genotyping and a clinical evaluation assessing comorbidity for Axis I and II psychiatric disorders, harm avoidance personality dimension and bulimic symptoms. The distribution of both tryptophan-hydroxylase-1 A218C genotypes and alleles did not significantly differ between patients and controls. Bulimic women with the AA genotype exhibited a more severe binge eating behavior and higher harm avoidance scores than those with CC genotype. These findings support the idea that tryptophan-hydroxylase-1 A218C polymorphism does not play a part in the genetic susceptibility to bulimia nervosa, but it seems to be involved in predisposing bulimic patients to a more disturbed eating behavior and higher harm avoidance.

  3. Identification of an evolutionary conserved structural loop that is required for the enzymatic and biological function of tryptophan 2,3-dioxygenase

    NARCIS (Netherlands)

    Michels, Helen; Seinstra, Renee I.; Uitdehaag, Joost C. M.; Koopman, Mandy; van Faassen, Martijn; Martineau, Celine N.; Kema, Ido P.; Buijsman, Rogier; Nollen, Ellen A. A.

    2016-01-01

    The enzyme TDO (tryptophan 2,3-dioxygenase; TDO-2 in Caenorhabditis elegans) is a potential therapeutic target to cancer but is also thought to regulate proteotoxic events seen in the progression of neurodegenerative diseases. To better understand its function and develop specific compounds that

  4. The effect of tryptophan supplemented diets on brain serotonergic activity and plasma cortisol under undisturbed and stressed conditions in grouped-housed Nile tilapia Oreochromis niloticus

    NARCIS (Netherlands)

    Martins, C.I.; Silva, P.I.M.; Costas, B.; Larsen, B.K.; Santos, G.A.; Conceicao, L.E.C.; Dias, J.; Overli, O.; Höglund, E.; Schrama, J.W.

    2013-01-01

    Tryptophan (TRP) supplemented diets have been shown to have therapeutic effects in farmed animals including fish by modulating the activity of the neurotransmitter serotonin (5-hydroxytryptamine; 5-HT). The effects reported in fish have been obtained using individually-housed fish and include a

  5. Aggression in Replacement Grower and Finisher Gilts fed a High-Tryptophan Diet and the Effect of Long-term Human-Animal Interaction

    Science.gov (United States)

    Aggression is a major problem for swine production as it negatively impacts the pigs’ health and welfare. Dietary approaches such as increasing tryptophan (TRP) ingestion to raise cerebral serotonin (5-HT) – a key neurotransmitter for aggression control, and long-term positive social handling have b...

  6. HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC PROFILING OF TRYPTOPHAN AND RELATED INDOLES IN BODY-FLUIDS AND TISSUES OF CARCINOID PATIENTS

    NARCIS (Netherlands)

    KEMA, IP; SCHELLINGS, AMJ; HOPPENBROUWERS, CJM; RUTGERS, HM; DEVRIES, EGE; MUSKIET, FAJ

    1993-01-01

    A high performance liquid chromatographic method with quaternary gradient elution and fluorometric detection was developed for profiling of tryptophan (TRP), 5-hydroxytryptophan, serotonin (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) in urine, platelet-rich plasma and (tumour) tissue of

  7. Assessment of the Potential Role of Tryptophan as the Precursor of Serotonin and Melatonin for the Aged Sleep-wake Cycle and Immune Function: as a Model

    Directory of Open Access Journals (Sweden)

    Sergio D. Paredes

    2009-01-01

    Full Text Available In the present review we summarize the relationship between the amino acid, tryptophan, the neurotransmitter, serotonin, and the indole, melatonin, with the rhythms of sleep/wake and the immune response along with the possible connections between the alterations in these rhythms due to aging and the so-called “serotonin and melatonin deficiency state.” The decrease associated with aging of the brain and circulating levels of serotonin and melatonin seemingly contributes to the alterations of both the sleep/wake cycle and the immune response that typically accompany old age. The supplemental administration of tryptophan, e.g. the inclusion of tryptophan-enriched food in the diet, might help to remediate these age-related alterations due to its capacity of raise the serotonin and melatonin levels in the brain and blood. Herein, we also summarize a set of studies related to the potential role that tryptophan, and its derived product melatonin, may play in the restoration of the aged circadian rhythms of sleep/wake and immune response, taking the ringdove ( Streptopelia risoria as a suitable model.

  8. Cell Adhesion on RGD-Displaying Knottins with Varying Numbers of Tryptophan Amino Acids to Tune the Affinity for Assembly on Cucurbit[8]uril Surfaces

    NARCIS (Netherlands)

    Sankaran, Shrikrishnan; Cavatorta, Emanuela; Huskens, Jurriaan; Jonkheijm, Pascal

    2017-01-01

    Cell adhesion is studied on multivalent knottins, displaying RGD ligands with a high affinity for integrin receptors, that are assembled on CB[8]-methylviologen-modified surfaces. The multivalency in the knottins stems from the number of tryptophan amino acid moieties, between 0 and 4, that can form

  9. Moderate whisky consumption in combination with an evening meal reduces tryptophan availability to the brain but does not influence performance in healthy volunteers

    NARCIS (Netherlands)

    Markus, C.R.; Sierksma, A.; Verbeek, C.; Rooijen, J.J.M. van; Patel, H.J.; Brand, A.N.; Hendriks, H.F.J.

    2004-01-01

    Brain serotonin (5-HT) synthesis is controlled by nutrients that influence the availability of plasma tryptophan (Trp) as compared with the sum of the other large neutral amino acids (LNAA; Trp:LNAA). Alcohol consumption is found to change mood and performance and this might well be due to