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https://www.readbyqxmd.com/read/29232124/mechanistic-studies-on-tryptophan-lyase-nosl-identification-of-cyanide-as-a-reaction-product
#1
Dhananjay M Bhandari, Dmytro Fedoseyenko, Tadhg P Begley
Tryptophan lyase catalyzes the formation of 3-methylindole-2-carboxylic acid and 3-methylindole from L-tryptophan. In this paper, we provide evidence supporting a formyl radical intermediate and demonstrate that cyanide is a byproduct of the NosL-catalyzed reaction with L-tryptophan. These experiments require a major revision of the NosL mechanism and uncover an unanticipated connection between NosL and HydG - the radical SAM enzyme that forms cyanide and carbon monoxide from tyrosine during the biosynthesis of the metallo cluster of the [Fe-Fe] hydrogenase...
December 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29202524/-effect-of-pts-modifications-on-l-tryptophan-production-in-escherichia-coli
#2
Tao Wu, Jinjin Zhao, Xianjun Mao
L-tryptophan, one of the aromatic amino acids, is widely used in the fields of medicine, food and feed additives. The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) plays an important role in glucose transport and phosphorylation in Escherichia coli. PTS-mediated regulation dominates the carbohydrates' uptake and metabolism in E. coli. We constructed L-tryptophan-producing bacteria containing two typical PTS mutations (ptsHIcrrglf⁻ glk⁺ and ptsG⁻) by Red homologous recombination system, and studied in 50 L jar fermenter using fed-batch fermentation...
November 25, 2017: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
https://www.readbyqxmd.com/read/29194091/menthol-reduces-phototoxicity-pain-in-a-mouse-model-of-photodynamic-therapy
#3
Lisa Wright, Daniel Baptista-Hon, Fiona Bull, Faith Dalgaty, Michael Gallacher, Sally H Ibbotson, Tim G Hales
Phototoxicity-induced pain is a major clinical problem triggered by light acting on photosensitising drugs or endogenous porphyrins, notably protoporphyrin IX (PpIX), an intermediary in heme biosynthesis. Protoporphyrin IX accumulates in individuals with erythropoietic protoporphyria and is elevated during photodynamic therapy subsequent to application of 5-aminolevulinic acid (ALA). Pain occurs during irradiation of PpIX and responds poorly to conventional analgesics. Our objective was to develop a model of PpIX phototoxicity pain and investigate the potential of menthol as an analgesic...
November 25, 2017: Pain
https://www.readbyqxmd.com/read/29185389/n-acetyl-l-tryptophan-a-substance-p-receptor-antagonist-attenuates-aluminum-induced-spatial-memory-deficit-in-rats
#4
Joylee Fernandes, Jayesh Mudgal, Chamallamudi Mallikarjuna Rao, Devinder Arora, Sanchari Basu Mallik, K S R Pai, Madhavan Nampoothiri
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...
November 29, 2017: Toxicology Mechanisms and Methods
https://www.readbyqxmd.com/read/29183601/involvement-of-h2o2-in-fluazifop-p-butyl-induced-cell-death-in-bristly-starbur-seedlings
#5
Xiaoyong Luo, Zhihang Liu, Yukari Sunohara, Hiroshi Matsumoto, Pingliang Li
In order to understand the action mechanism of fluazifop-P-butyl (FB) in bristly starbur (Acanthospermum hispidum D.C.), a susceptible plant, the role of active oxygen species (ROS) in herbicide-induced cell death in shoots was investigated. FB-induced phytotoxicity was not reduced by the antioxidants, 1,4-diazabicyclooctane (dabaco), sodium azide, l-tryptophan, d-tryptophan, hydroquinone and dimethyl pyridine N-oxide (DMPO). The activities of superoxide dismutase (SOD) and catalase (CAT), in bristly starbur seedlings were significantly increased by FB at 12 HAT and 24 HAT, while ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased only at 12 HAT...
November 2017: Pesticide Biochemistry and Physiology
https://www.readbyqxmd.com/read/29169940/enrichment-of-cellulose-acetate-nanofibre-assemblies-for-therapeutic-delivery-of-l-tryptophan
#6
Behrouz Ghorani, Parikshit Goswami, Richard S Blackburn, Stephen J Russell
The essential amino acid L-tryptophan is naturally present in the body, and is also available as a water soluble dietary supplement. The feasibility of preparing enriched cellulose acetate (CA)-based fibres as a vehicle for therapeutic delivery of such biomolecules was investigated. A new ternary solvent system consisting of acetone: N,N-dimethylacetamide: methanol (2:1:2) has been demonstrated to permit the solution blending of CA with the water soluble L-tryptophan. Nanofibrous webs substantially free of structural defects were continuously produced with mean fibre diameters in the range of 520-1,010nm, dependent on process parameters...
November 20, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29143967/thirteen-week-toxicity-study-of-dietary-l-tryptophan-in-rats-with-a-recovery-period-of-5%C3%A2-weeks
#7
Yusuke Shibui, Hideki Matsumoto, Yoko Masuzawa, Takumi Ohishi, Tsutomu Fukuwatari, Katsumi Shibata, Ryosei Sakai
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...
November 16, 2017: Journal of Applied Toxicology: JAT
https://www.readbyqxmd.com/read/29138359/comparative-effects-of-intraduodenal-amino-acid-infusions-on-food-intake-and-gut-hormone-release-in-healthy-males
#8
Robert E Steinert, Sina S Ullrich, Nori Geary, Lori Asarian, Marco Bueter, Michael Horowitz, Christine Feinle-Bisset
In contrast to the many studies of the effects of individual amino acids (AAs) on eating, no studies have compared the effects of different AAs on eating and underlying preabsorptive gastrointestinal mechanisms. To compare the effects of intraduodenal infusions of l-tryptophan (TRP), l-leucine (LEU), l-phenylalanine (PHE) and l-glutamine (GLN) on appetite, gastrointestinal hormone responses (including ghrelin, cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 [GLP-1]), glycemia (glucagon, insulin and glucose) and test meal size in healthy males, we retrospectively analyzed data from four published independent, randomized, double-blind, placebo-controlled studies of 90-min intraduodenal infusions of the individual AAs...
November 2017: Physiological Reports
https://www.readbyqxmd.com/read/29136908/chiral-recognition-of-tryptophan-enantiomers-using-chitosan-capped-silver-nanoparticles-scanometry-and-spectrophotometry-approaches
#9
Marzieh Jafari, Javad Tashkhourian, Ghodratollah Absalan
A new, fast and inexpensive colorimetric sensor was developed for chiral recognition of tryptophan enantiomers using chitosan-capped silver nanoparticles. The function of the sensor was based on scanometry and spectrophotometry of the colored product of a reaction solution containing a mixture of chitosan-capped silver nanoparticles, phosphate buffer and tryptophan enantiomers. The image of the colored solution was taken using the scanometer and the corresponding color values were obtained using Photoshop software which subsequently were used for optimization of the experimental parameters as the analytical signal...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29115321/raman-microspectroscopy-and-multivariate-data-analysis-optical-differentiation-of-aqueous-d-and-l-tryptophan-solutions
#10
H Koch, S Polepil, K Eisen, S Will
The combination of Raman spectroscopy as a sensitive and selective optical measurement technique and multivariate data analysis forms a powerful tool for probing intermolecular interactions between enantiomers. In this study we demonstrate that the optical differentiation of aqueous d- and l-tryptophan solutions is possible using Raman spectroscopy and principal component analysis (PCA). The loadings of the PCA allow identifying these functional groups most relevant for enantiospecific interactions. Through a partial least squares regression (PLSR) a calibration line can be established for the mixing ratio of ternary aqueous d- and l-tryptophan solutions...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29112406/nicrophorusamides-a-and-b-antibacterial-chlorinated-cyclic-peptides-from-a-gut-bacterium-of-the-carrion-beetle-nicrophorus-concolor
#11
Yern-Hyerk Shin, Suhyun Bae, Jaehoon Sim, Joonseong Hur, Shin-Il Jo, Jongheon Shin, Young-Ger Suh, Ki-Bong Oh, Dong-Chan Oh
Nicrophorusamides A and B (1 and 2) were discovered from a rare actinomycete, Microbacterium sp., which was isolated from the gut of the carrion beetle Nicrophorus concolor. The structures of the nicrophorusamides were established as new chlorinated cyclic hexapeptides bearing uncommon amino acid units mainly based on 1D and 2D NMR spectroscopic analysis. The absolute configurations of the amino acid residues 5-chloro-l-tryptophan, d-threo-β-hydroxyasparagine/d-asparagine, l-ornithine, l-allo-isoleucine, d-leucine, and d-valine were determined using Marfey's method and chemical derivatization with 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate followed by LC/MS analysis...
November 7, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29105163/in-vitro-effects-of-inulin-and-soya-bean-oligosaccharide-on-skatole-production-and-the-intestinal-microbiota-in-broilers
#12
H Y Liu, R Hou, G Q Yang, F Zhao, W G Dong
The experiment was conducted to investigate the in vitro effects of inulin and soya bean oligosaccharide (SBO) on the metabolism of L-tryptophan (L-try) to skatole production, and the intestinal microbiota in broilers. Treatments were as follows: caecal microbiota control (Cc), Cc + inulin, Cc + SBO, rectal microbiota control (Rc), Rc + inulin and Rc + SBO. Microbial suspensions were anaerobically incubated at 38°C for 24 hr. The results showed that concentrations of skatole and acetic acid were significantly lower in caecal microbiota fermentation broth (MFB) than those in rectal MFB (p < ...
November 3, 2017: Journal of Animal Physiology and Animal Nutrition
https://www.readbyqxmd.com/read/29104243/diverse-secondary-metabolites-from-the-marine-derived-fungus-dichotomomyces-cejpii-f31-1
#13
Yan-Xiu Chen, Meng-Yang Xu, Hou-Jin Li, Kun-Jiao Zeng, Wen-Zhe Ma, Guo-Bao Tian, Jun Xu, De-Po Yang, Wen-Jian Lan
By adding l-tryptophan and l-phenylalanine to GPY medium, twenty-eight compounds, including amides, polyketides, a sesquiterpenoid, a diterpenoid, a meroterpenoid, diketopiperazines, β-carbolines, fumiquinazolines, and indole alkaloids, were discovered from the marine-derived fungus Dichotomomyces cejpii F31-1, demonstrating the tremendous biosynthetic potential of this fungal strain. Among these compounds, four amides dichotomocejs A-D (1-4), one polyketide dichocetide A (5), and two diketopiperazines dichocerazines A-B (15 and 16) are new...
November 1, 2017: Marine Drugs
https://www.readbyqxmd.com/read/29102139/short-communication-supplementation-of-colostrum-and-milk-with-5-hydroxy-l-tryptophan-affects-immune-factors-but-not-growth-performance-in-newborn-calves
#14
Lorenzo E Hernández-Castellano, Ranya Özçelik, Laura L Hernandez, Rupert M Bruckmaier
In ruminants, colostrum is the main source of immunoglobulins for the newborn animal, conferring immune protection until the immune system becomes active and able to synthesize its own immunoglobulins. Serotonin (5-HT), a biogenic amine derived from tryptophan, has stimulatory effects on many physiological processes, including components of the innate (mastocytes, eosinophils, and natural killer cells) and adaptive (T and B lymphocytes) immune systems. Based on the known effects of 5-HT on the immune system, we hypothesized that increased concentrations of 5-HT, through administration of its precursor 5-hydroxy-l-tryptophan (5-HTP), may positively affect development of the calf's immune system and therefore support health and growth performance during the first weeks of life...
October 25, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/29100619/indoxyl-3-sulfate-inhibits-maturation-and-activation-of-human-monocyte-derived-dendritic-cells
#15
Sakhila Ghimire, Carina Matos, Massimiliano Caioni, Daniela Weber, Katrin Peter, Ernst Holler, Marina Kreutz, Kathrin Renner
Indole is produced from l-tryptophan by commensal bacteria and further metabolized to indoxyl 3-sulfate (I3S) in the liver. Physiologic concentrations of I3S are related to a lower risk to develop graft versus host disease in allogeneic stem cell transplanted patients pointing towards an immunoregulatory function of I3S. Here we investigated the impact of I3S on the maturation of human monocyte-derived dendritic cells (DCs). Even pathophysiologic concentrations of I3S did not affect viability of mature DCs, but I3S decreased the expression of co-stimulatory molecules such as CD80 and CD86 on mature DCs...
October 6, 2017: Immunobiology
https://www.readbyqxmd.com/read/29083895/genomics-driven-discovery-of-chlorinated-cyclic-hexapeptides-ulleungmycins-a-and-b-from-a-streptomyces-species
#16
Sangkeun Son, Young-Soo Hong, Mina Jang, Kyung Taek Heo, Byeongsan Lee, Jun-Pil Jang, Jong-Won Kim, In-Ja Ryoo, Won-Gon Kim, Sung-Kyun Ko, Bo Yeon Kim, Jae-Hyuk Jang, Jong Seog Ahn
Analysis of the genome sequence of Streptomyces sp. KCB13F003 showed the presence of a cryptic gene cluster encoding flavin-dependent halogenase and nonribosomal peptide synthetase. Pleiotropic approaches using multiple culture media followed by LC-MS-guided isolation and spectroscopic analysis enabled the identification of two new chlorinated cyclic hexapeptides, ulleungmycins A and B (1 and 2). Their structures, including absolute configurations, were determined by 1D and 2D NMR techniques, advanced Marfey's analysis, and GITC derivatization...
October 30, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29058562/does-l-tryptophan-supplementation-reduce-chewing-deficits-in-an-experimental-model-of-cerebral-palsy
#17
Diego Cabral Lacerda, Raul Manhães-de-Castro, Kelli Nogueira Ferraz-Pereira, Ana Elisa Toscano
Children with cerebral palsy commonly present with feeding difficulties that result from multiple orofacial sequelae, especially deficits in mastication. A previous study demonstrated that perinatal protein undernutrition accentuated the chewing impact in an experimental model of cerebral palsy. Therefore, the present study investigated whether nutritional manipulation reversed or minimized the chewing sequelae in cerebral palsy. We emphasized the relevance of evaluating the therapeutic potential of nutrients, especially tryptophan supplementation, to reduce the chewing deficits that are typical of this syndrome...
October 23, 2017: Nutritional Neuroscience
https://www.readbyqxmd.com/read/29046831/self-assembly-of-chiral-fluorescent-nanoparticles-based-on-water-soluble-l-tryptophan-derivatives-of-p-tert-butylthiacalix-4-arene
#18
Pavel L Padnya, Irina A Khripunova, Olga A Mostovaya, Timur A Mukhametzyanov, Vladimir G Evtugyn, Vyacheslav V Vorobev, Yuri N Osin, Ivan I Stoikov
New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86-134 nm in diameter in water at a concentration of 1 × 10(-4) M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/29037509/structure-determination-of-disease-associated-peak-aaa-from-l-tryptophan-implicated-in-the-eosinophilia-myalgia-syndrome
#19
Klaus Klarskov, Hugo Gagnon, Pierre-Luc Boudreault, Chad Normandin, Baptiste Plancq, Eric Marsault, Gerald J Gleich, Stephen Naylor
The eosinophilia-myalgia syndrome (EMS) outbreak of 1989 that occurred in the USA and elsewhere was caused by the ingestion of l-Tryptophan (L-Trp) solely manufactured by the Japanese company Showa Denko K.K. (SD). Six compounds present in the SD L-Trp were reported to be case-associated contaminants. However, "one" of these compounds, Peak AAA has remained structurally uncharacterized, despite the fact that it was described as "the only statistically significant (p=0.0014) contaminant". Here, we employ on-line microcapillary-high performance liquid chromatography-electrospray ionization mass spectrometry (LC-MS), and tandem mass spectrometry (MS/MS) to determine that Peak AAA is in fact two structurally related isomers...
October 14, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/29024806/dimerization-and-oxidation-of-tryptophan-in-uv-a-photolysis-sensitized-by-kynurenic-acid
#20
Ekaterina D Sormacheva, Peter S Sherin, Yuri P Tsentalovich
Photoinduced generation of radicals in the eye lens may play an important role in the modification of proteins leading to their coloration, aggregation, and insolubilization. The radicals can be formed via the reactions of photoexcited endogenous chromophores of the human lens with lens proteins, in particular with tryptophan residues. In the present work we studied the reactions induced by UV-A (315-400nm) light between kynurenic acid (KNA), an effective photosensitizer present in the human lens, and N-acetyl-L-tryptophan (NTrpH) under aerobic and anaerobic conditions...
October 9, 2017: Free Radical Biology & Medicine
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