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https://www.readbyqxmd.com/read/28600214/validation-of-onchocerciasis-biomarker-n-acetyltyramine-o-glucuronide-natog
#1
Daniel Globisch, Lisa M Eubanks, Ryan J Shirey, Kenneth M Pfarr, Samuel Wanji, Alexander Y Debrah, Achim Hoerauf, Kim D Janda
The Neglected Tropical Disease onchocerciasis is a parasitic disease. Despite many control programmes by the World Health Organization (WHO), large communities in West and Central Africa are still affected. Besides logistic challenges during biannual mass drug administration, the lack of a robust, point-of-care diagnostic is limiting successful eradication of onchocerciasis. Towards the implementation of a non-invasive and point-of-care diagnostic, we have recently reported the discovery of the biomarker N-acetyltyramine-O-glucuronide (NATOG) in human urine samples using a metabolomics-mining approach...
May 29, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28594102/the-inhibition-effects-of-some-natural-products-on-lactoperoxidase-purified-from-bovine-milk
#2
Zeynep Köksal, Ramazan Kalın, Serpil Gerni, İlhami Gülçin, Hasan Özdemir
In this study, inhibition profiles of some natural products, which are digoxin, L-Dopa, dopamine, isoliquiritigenin, and 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane (Tetrakis), were investigated against bovine lactoperoxidase (LPO) enzyme. Digoxin, L-Dopa, and dopamine are active ingredients of some drugs, which have important functions in our body, especially in cases of heart failure. Isoliquiritigenin and tetrakis are types of natural phenolic compounds, which play an important role in cancer prevention and treatment...
June 8, 2017: Journal of Biochemical and Molecular Toxicology
https://www.readbyqxmd.com/read/28584384/multigram-scale-synthesis-of-enantiopure-3-3-difluoroproline
#3
Christelle Doebelin, Yuanjun He, Theodore M Kamenecka
An efficient route for the synthesis of enantiopure 3,3-difluoroproline on multigram-scale is described herein. The deoxofluorination can be achieved with DAST on the corresponding racemic pyrrolidinone in good yield. Resolution of the racemate by crystallization with D- and L-tyrosine hydrazide provides both enantiomers of 3,3-difluoroproline in high yield and ee%.
December 14, 2016: Tetrahedron Letters
https://www.readbyqxmd.com/read/28572813/cytosolic-and-nuclear-co-localization-of-betalain-biosynthetic-enzymes-in-tobacco-suggests-that-betalains-are-synthesized-in-the-cytoplasm-and-or-nucleus-of-betalainic-plant-cells
#4
Ning Chen, Zhi-Hai Yu, Xing-Guo Xiao
Betalains replace anthocyanins as color pigments in most families of Caryophyllales. Unlike anthocyanins, betalains are derived from tyrosine via three enzymatic steps: hydroxylation of L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA; step 1), and conversion of L-DOPA to betalamic acid (step 2), and to cyclo-DOPA (cDOPA; step 3). The principal enzymes responsible for these reactions have been elucidated at the molecular level, but their subcellular localizations have not been explored; hence, the intracellular compartments wherein betalains are biosynthesized remain unknown...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28571714/l-tyrosine-availability-affects-basal-and-stimulated-catecholamine-indices-in-prefrontal-cortex-and-striatum-of-the-rat
#5
Zachary D Brodnik, Manda Double, Rodrigo A España, George E Jaskiw
We previously found that L-tyrosine (L-TYR) but not D-TYR administered by reverse dialysis elevated catecholamine synthesis in vivo in medial prefrontal cortex (MPFC) and striatum of the rat (Brodnik et al., 2012). We now report L-TYR effects on extracellular levels of catecholamines and their metabolites. In MPFC, reverse dialysis of L-TYR elevated in vivo levels of dihydroxyphenylacetic acid (DOPAC) (L-TYR 250-1000 μM), homovanillic acid (HVA) (L-TYR 1000 μM) and 3-methoxy-4-hydroxyphenylglycol (MHPG) (L-TYR 500-1000 μM)...
May 29, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28570917/improved-method-for-preparing-ni-ii-complex-of-s-tyrosine-schiff-base-and-its-use-in-the-automated-synthesis-of-o-2-18-f-fluoroethyl-l-tyrosine-using-solid-phase-extraction-purification
#6
N Lakshminarayanan, Amit Kumar, Sushant Roy, Yogita Pawar, Pradip Chaudhari, M G R Rajan
O-(2'-[(18)F]fluoroethyl)-l-tyrosine is reportedly suitable for PET-imaging of brain tumours. We report here the synthesis of Ni(II)-complex of Schiff's base (S)-[N-2-(N'-benzylprolyl)amino]-benzophenone,((S)BPB) and alkylated l-tyrosine precursor, Ni(II)-(S)-BPB-l-Tyr-O-CH2-CH2-OTs by an improved method. A fully-automated radio-synthesis including non-HPLC purification was developed with a radio-chemical yield of 24.6 ± 2% in 70 ± 2min (n = 5). Radiochemical and enantiomeric purity was > 98% and 94% respectively...
May 22, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28570907/melanin-gamma-rays-assistants-for-bismuth-oxide-nanoparticles-synthesis-at-room-temperature-for-enhancing-antimicrobial-and-photocatalytic-activity
#7
Ahmed I El-Batal, Gharieb S El-Sayyad, Abbas El-Ghamry, Kerolos M Agaypi, Mohamed A Elsayed, Mohamed Gobara
Melanin pigment has been deemed as a natural photoprotector with strong hydrophobicity. It allured considerable compatibility with many applications in medicine, food, and nanotechnology. Penicillium chrysogenium has been devoted to the green synthesis of melanin whereby optimizing its culture and environmental conditions. The impacts of alternative economic L-tyrosine natural sources (unprecedented alternate origins) and gamma radiation were pledged for the potential growing of the pigment. Herein, notable increases in melanin yield (6...
May 23, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28564546/polyurethane-microgel-based-microtissue-interface-guided-assembly-and-spreading
#8
Michael J Hill, Debanjan Sarkar
Colloidal gels are three-dimensional networks of microgel particles and can be utilized to design microtissues where the differential adhesive interactions between the particles and cells, guided by their surface energetics, are engineered to spatially assemble the cellular and colloidal components into three-dimensional microtissues. In this work we utilized a colloidal interaction approach to design cell-polyurethane (PU) microgel bimodal microtissues using endothelial cells (ECs) as a normal cell model and a nonmalignant breast cancer cell line (MCF-7) as a cancer cell model...
June 9, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28560582/towards-standardization-of-18-f-fet-pet-imaging-do-we-need-a-consistent-method-of-background-activity-assessment
#9
Marcus Unterrainer, Franziska Vettermann, Matthias Brendel, Adrien Holzgreve, Michael Lifschitz, Matthias Zähringer, Bogdana Suchorska, Vera Wenter, Ben M Illigens, Peter Bartenstein, Nathalie L Albert
BACKGROUND: PET with O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) has reached increasing clinical significance for patients with brain neoplasms. For quantification of standard PET-derived parameters such as the tumor-to-background ratio, the background activity is assessed using a region of interest (ROI) or volume of interest (VOI) in unaffected brain tissue. However, there is no standardized approach regarding the assessment of the background reference. Therefore, we evaluated the intra- and inter-reader variability of commonly applied approaches for clinical (18)F-FET PET reading...
December 2017: EJNMMI Research
https://www.readbyqxmd.com/read/28552264/imaging-of-amino-acid-transport-in-brain-tumours-positron-emission-tomography-with-o-2-18-f-fluoroethyl-l-tyrosine-fet
#10
REVIEW
Karl-Josef Langen, Gabriele Stoffels, Christian Filß, Alexander Heinzel, Carina Stegmayr, Philipp Lohmann, Antje Willuweit, Bernd Neumaier, Felix M Mottaghy, Norbert Galldiks
The assessment of cerebral gliomas using magnetic resonance imaging (MRI) provides excellent structural images but cannot solve all diagnostic problems satisfactorily. The differentiation of tumour tissue from non-neoplastic changes may be difficult especially in the post-treatment phase. In recent years, positron emission tomography (PET) using radiolabelled amino acids has gained considerable interest as an additional tool to improve the diagnosis of cerebral gliomas and brain metastases. A key step for this advancement was the development of the F-18 labelled amino acid O-(2-[(18)F]fluoroethyl)-L-tyrosine (FET) which has spread rapidly in the last decade and replaced carbon-11 labelled amino acid tracers such as (11)C-methyl-L-methionine (MET) in many centres in Europe...
May 24, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28547180/role-of-antioxidant-treatment-on-dna-and-lipid-damage-in-the-brain-of-rats-subjected-to-a-chemically-induced-chronic-model-of-tyrosinemia-type-ii
#11
Emilio L Streck, Samira D T De Prá, Paula Ronsani Ferro, Milena Carvalho-Silva, Lara M Gomes, Jotele F Agostini, Adriani Damiani, Vanessa M Andrade, Patrícia F Schuck, Gustavo C Ferreira, Giselli Scaini
Tyrosine levels are abnormally elevated in tissues and body fluids of patients with inborn errors of tyrosine metabolism. Tyrosinemia type II, which is caused by tyrosine aminotransferase deficiency, provokes eyes, skin, and central nervous system disturbances in affected patients. However, the mechanisms of brain damage are still poorly known. Considering that studies have demonstrated that oxidative stress may contribute, along with other mechanisms, to the neurological dysfunction characteristic of hypertyrosinemia, in the present study we investigated the effects of antioxidant treatment (NAC and DFX) on DNA damage and oxidative stress markers induced by chronic administration of L-tyrosine in cerebral cortex, hippocampus, and striatum of rats...
May 25, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28526263/n-stearoyl-l-tyrosine-inhibits-the-cell-senescence-and-apoptosis-induced-by-h2o2-in-hek293-tau-cells-via-the-cb2-receptor
#12
Yue Hu, Kai-Yi Zhou, Ze-Jian Wang, Yang Lu, Ming Yin
Although considerable energy and money have been spent trying to inhibit Aβ production and its related metabolic enzyme activities, there are still no drug treatments available to cure even slow for Alzheimer's disease. Therefore, tau protein has been focused recently as the new target for the treatment of Alzheimer's disease. The transfected human embryonic kidney 293 (HEK 293) cells with or without Tau 411 plasmid were used to evaluate the effect of tau protein on cell viability. H2O2 was added to simulate microenvironment of oxidative stress (OS) during aging...
June 25, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/28511681/chromosome-engineering-of-escherichia-coli-for-constitutive-production-of-salvianic-acid-a
#13
Liang Zhou, Qi Ding, Guo-Zhen Jiang, Zhen-Ning Liu, Hai-Yan Wang, Guang-Rong Zhao
BACKGROUND: Salvianic acid A (SAA), a valuable natural product from herbal plant Salvia miltiorrhiza, exhibits excellent antioxidant activities on food industries and efficacious therapeutic potential on cardiovascular diseases. Recently, production of SAA in engineered Escherichia coli was established via the artificial biosynthetic pathway of SAA on the multiple plasmids in our previous work. However, the plasmid-mediated system required to supplement expensive inducers and antibiotics during the fermentation process, restricting scale-up production of SAA...
May 16, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28493648/detection-of-localized-hepatocellular-amino-acid-kinetics-by-using-mass-spectrometry-imaging-of-stable-isotopes
#14
Martijn Arts, Zita Soons, Shane R Ellis, Keely A Pierzchalski, Benjamin Balluff, Gert B Eijkel, Ludwig J Dubois, Natasja G Lieuwes, Stijn M Agten, Tilman M Hackeng, Luc J C van Loon, Ron M A Heeren, Steven W M Olde Damink
Mass spectrometry imaging (MSI) simultaneously detects and identifies the spatial distribution of numerous molecules throughout tissues. Currently, MSI is limited to providing a static and ex vivo snapshot of highly dynamic systems in which molecules are constantly synthesized and consumed. Herein, we demonstrate an innovative MSI methodology to study dynamic molecular changes of amino acids within biological tissues by measuring the dilution and conversion of stable isotopes in a mouse model. We evaluate the method specifically on hepatocellular metabolism of the essential amino acid l-phenylalanine, associated with liver diseases...
June 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28477375/oral-l-tyrosine-supplementation-augments-the-vasoconstriction-response-to-whole-body-cooling-in-older-adults
#15
James A Lang, Kevin A Smaller
L-tyrosine is the primary substrate for noradrenaline biosynthesis within sympathetic axon terminals. Under stressful conditions requiring increased catecholamine production, axonal L-tyrosine concentration may limit the full expression of the sympathetic effector response and this may be particularly evident in older adults. We hypothesize that oral L-tyrosine supplementation will increase the sympathetic response to whole-body cooling and muscle metaboreflex activation. In a randomized, double-blind design, eleven young (Y = 24 ± 1 years) and eleven older (O = 68 ± 4 years) participants ingested either 150 mg kg(-1) of L-tyrosine or placebo prior to commencing 30 minutes of whole-body cooling to induce a gradual decline in skin temperature from 34 to 30...
May 5, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28459864/tyrosinase-inhibitory-activity-molecular-docking-studies-and-antioxidant-potential-of-chemotypes-of-lippia-origanoides-verbenaceae-essential-oils
#16
Alessandra P da Silva, Natália de F Silva, Eloísa Helena A Andrade, Tais Gratieri, William N Setzer, José Guilherme S Maia, Joyce Kelly R da Silva
The essential oils (EOs) of the aerial parts of Lippia origanoides (LiOr), collected in different localities of the Amazon region, were obtained by hydrodistillation and analyzed by GC and CG-MS. Principle component analysis (PCA) based on chemical composition grouped the oils in four chemotypes rich in mono- and sesquiterpenoids. Group I was characterized by 1,8-cineole and α-terpineol (LiOr-1 and LiOr-4) and group II by thymol (LiOr-2). The oil LiOr-3 showed β-caryophyllene, α-phellandrene and β-phellandrene as predominant and LiOr-5 was rich in (E)-nerolidol and β-caryophyllene...
2017: PloS One
https://www.readbyqxmd.com/read/28456625/effects-of-matsutake-mushroom-scent-compounds-on-tyrosinase-and-murine-b16-f10-melanoma-cells
#17
Hiroki Satooka, Philip Cerda, Hae-Jung Kim, William F Wood, Isao Kubo
Tyrosinase-catalyzed l-tyrosine oxidation is a key step in melanogenesis, and intense melanin formation is often a problem in chemotherapies or food preservation. Here we report that methyl cinnamate one of the constituents characterized from mycelium and sporocarp of American matsutake mushroom Tricholoma magnivelare inhibits both enzymatic and cellular melanin formation. Methyl cinnamate inhibits mushroom tyrosinase-catalyzed l-tyrosine oxidation while the oxidation of l-3,4-dihydroxyphenylalanine (l-DOPA) was not inhibited...
June 10, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28445766/inhibitory-effect-of-emulsifiers-in-sedds-on-protease-activity-just-an-illusion
#18
Noemi Lupo, Una Fidahic, Gergely Hetényi, Janine Griesser, Andreas Bernkop-Schnürch
AIM: Evaluation of inhibitory effect of emulsifiers on pancreatic trypsin and α-chymotrypsin. METHODS: The inhibitory effect of Cremophor EL, Cremophor RH 40, Brij O10, Tween 20, polyethylene glycol 8000, polyethylene glycol 400, Carbitol, Pemulen TR-1, Pemulen TR-2, Carbopol Ultrez 20 and Carbopol Ultrez 21 on pancreatic trypsin and α-chymotrypsin was tested. BAEE (Nα-Benzoyl-l-arginine ethyl ester), BTEE (N-Benzoyl-l-tyrosine ethyl ester), casein and insulin were used as substrates for trypsin and α-chymotrypsin...
April 23, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28435719/crystal-structure-of-o-benzyl-l-tyrosine-n-carb-oxy-anhydride
#19
Aya Inada, Hitoshi Kanazawa
In the title compound, C17H15NO4 (alternative name; O-benzyl-l-tyrosine N-carb-oxy anhydride), the oxazolidine ring is planer, with an r.m.s. deviation of 0.039 Å. The benz-yloxy and benzyl rings are almost coplanar, making a dihedral angle of 0.078 (10)°, and are inclined to the oxazolidine ring by 59.16 (11) and 58.42 (11)°, respectively. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds, forming ribbons propagating along [010]. The ribbons are linked by C-H⋯π inter-actions, forming a three-dimensional supra-molecular structure...
April 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28430025/synthesis-of-dopamine-in-e-coli-using-plasmid-based-expression-system-and-its-marked-effect-on-host-growth-profiles
#20
Arunangshu Das, Anita Verma, Krishna J Mukherjee
L-Dopa and dopamine are important pathway intermediates toward the synthesis of catecholamine such as epinephrine and norepinephrine from amino acid L-tyrosine. Dopamine, secreted from dopaminergic nerve cells, serves as an important neurotransmitter. We report the synthesis of dopamine by extending the aromatic amino acid pathway of Escherichia coli DH5α by the expression of 4-hydroxyphenylacetate-3-hydrolase (HpaBC) from E. coli and an engineered dopa decarboxylase (DDC) from pig kidney cell. The activity of HpaBC and DDC require 200 µM iron supplementation and 50 µM vitamin B6, respectively as additives to the growth media...
April 21, 2017: Preparative Biochemistry & Biotechnology
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