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https://www.readbyqxmd.com/read/28716505/%C3%AE-methyltyrosine-a-tyrosine-hydroxylase-inhibitor-decreases-stress-response-in-zebrafish-danio-rerio
#1
Renan Idalencio, Heloísa Helena de Alcantara Barcellos, Fabiana Kalichak, João Gabriel Santos da Rosa, Thiago Acosta Oliveira, Murilo Sander de Abreu, Michele Fagundes, Fernanda Dametto, Letícia Marcheto, Caio Maximino de Oliveira, Leonardo José Gil Barcellos
In this article, we show that the tyrosine hydroxylase inhibitor α-Methyl-L-tyrosine (AMPT) decreased the responsiveness of the zebrafish stress axis to an acute stressful challenge. These effects were specific for responses to stimulation, since unstimulated (basal) cortisol levels were not altered by AMPT. Moreover, AMPT decreased the stress response 15 min after stimulation, but not after that time period. To our knowledge, this is the first report about the effects of AMPT on the neuroendocrine axis of adult zebrafish in acute stress responses...
July 14, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28711224/the-radioprotector-ortho-phospho-l-tyrosine-ptyr-attenuates-the-side-effects-of-fractionated-irradiation-in-retinoblastoma-mouse-models-but-also-decreases-the-local-tumour-control
#2
Alexander V Tschulakow, Klaus Dittmann, Stephan M Huber, Dominik Klumpp, Benjamin Stegen, Ulrich Schraermeyer, H Peter Rodemann, Sylvie Julien-Schraermeyer
BACKGROUND: Radiotherapy (RT) is used to treat retinoblastoma (Rb), the most frequent ocular tumour in children. Besides eradicating the tumour, RT can cause severe side effects including secondary malignancies. This study aimed to define whether the radioprotector ortho-phospho-L-tyrosine (pTyr) prevents RT-induced side effects and affects local tumour control in a xenograft and a genetic orthotopic Rb mouse model. METHODS: B6;129-Rb1tm3Tyj/J (Rb(+/-)) and Y79-Rb cell-xenografted nude mice were fractionated external beam irradiated (15 fractions of 5Gy 6MV photons during 3weeks) with or without pTyr pre-treatment (100mg/kg BW, 16h prior to each irradiation)...
July 12, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28687763/a-tyrosine-aminotransferase-involved-in-rosmarinic-acid-biosynthesis-in-prunella-vulgaris-l
#3
Mei Ru, Kunru Wang, Zhenqing Bai, Liang Peng, Shaoxuan He, Yong Wang, Zongsuo Liang
Rosmarinic acid (RA) and its derivants are medicinal compounds that comprise the active components of several therapeutics. We isolated and characterised a tyrosine aminotransferase of Prunella vulgaris (PvTAT). Deduced PvTAT was markedly homologous to other known/putative plant TATs. Cytoplasmic localisation of PvTAT was observed in tobacco protoplasts. Recombinantly expressed and purified PvTAT had substrates preference for L-tyrosine and phenylpyruvate, with apparent K m of 0.40 and 0.48 mM, and favoured the conversion of tyrosine to 4-hydroxyphenylpyruvate...
July 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28680873/amino-acid-pet-and-mr-perfusion-imaging-in-brain-tumours
#4
REVIEW
Christian P Filss, Francesco Cicone, Nadim Jon Shah, Norbert Galldiks, Karl-Josef Langen
PURPOSE: Despite the excellent capacity of the conventional MRI to image brain tumours, problems remain in answering a number of critical diagnostic questions. To overcome these diagnostic shortcomings, PET using radiolabeled amino acids and perfusion-weighted imaging (PWI) are currently under clinical evaluation. The role of amino acid PET and PWI in different diagnostic challenges in brain tumours is controversial. METHODS: Based on the literature and experience of our centres in correlative imaging with PWI and PET using O-(2-[(18)F]fluoroethyl)-l-tyrosine or 3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine, the current role and shortcomings of amino acid PET and PWI in different diagnostic challenges in brain tumours are reviewed...
2017: Clinical and Translational Imaging: Reviews in Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/28678407/homochiral-metal-organic-frameworks-based-on-amino-acid-ligands-for-hplc-separation-of-enantiomers
#5
Jun-Hui Zhang, Rui-Yu Nong, Bang-Jin Wang, Ping Ai, Sheng-Ming Xie, Li-Ming Yuan
Natural amino acids are well known to form coordination polymers with transition metal ions. In this study, six homochiral metal-organic frameworks constructed from Zn(2+) or Co(2+) ions and various enantiopure amino acid (L-tyrosine, L-histidine, L-tryptophan and L-glutamic acid), namely [Zn(L-tyr)]n (L-tyrZn), [Zn4 (btc)2 (Hbtc)(L-His)2 (H2 O)4 ]·1.5H2 O, {[Zn2 (L-trp)2 (bpe)2 (H2 O)2 ]·2H2 O·2NO3 }n , [Co2 (L-Trp)(INT)2 (H2 O)2 (ClO4 )], [Co2 (sdba)((L-Trp)2 ] and [Co(L-Glu)(H2 O)·H2 O]∞ , were synthesized according to the methods previously reported in the literature...
July 5, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28674386/metabolic-and-microbial-signatures-in-rat-hepatocellular-carcinoma-treated-with-caffeic-acid-and-chlorogenic-acid
#6
Zhan Zhang, Di Wang, Shanlei Qiao, Xinyue Wu, Shuyuan Cao, Li Wang, Xiaojian Su, Lei Li
Hepatocellular carcinoma (HCC) treatment remains lack of effective chemopreventive agents, therefore it is very attractive and urgent to discover novel anti-HCC drugs. In the present study, the effects of chlorogenic acid (ChA) and caffeic acid (CaA) on HCC induced by diethylnitrosamine (DEN) were evaluated. ChA or CaA could reduce the histopathological changes and liver injury markers, such as alanine transarninase, aspartate aminotransferase, alkaline phosphatase, total bile acid, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol...
July 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28671678/molecular-basis-of-the-evolution-of-alternative-tyrosine-biosynthetic-routes-in-plants
#7
Craig A Schenck, Cynthia K Holland, Matthew R Schneider, Yusen Men, Soon Goo Lee, Joseph M Jez, Hiroshi A Maeda
L-Tyrosine (Tyr) is essential for protein synthesis and is a precursor of numerous specialized metabolites crucial for plant and human health. Tyr can be synthesized via two alternative routes by different key regulatory TyrA family enzymes, prephenate dehydrogenase (PDH, also known as TyrAp) or arogenate dehydrogenase (ADH, also known as TyrAa), representing a unique divergence of primary metabolic pathways. The molecular foundation underlying the evolution of these alternative Tyr pathways is currently unknown...
June 26, 2017: Nature Chemical Biology
https://www.readbyqxmd.com/read/28645884/investigation-of-the-effects-of-lycium-barbarum-polysaccharides-against-cadmium-induced-damage-in-testis
#8
Maria Vittoria Varoni, Sergio Domenico Gadau, Valeria Pasciu, Elena Baralla, Elisa Serra, Domenico Palomba, Maria Piera Demontis
This study describes the effects of Lycium barbarum polysaccharides (LBP) on testicular damage induced by cadmium (Cd). Adult male rats were i.p. injected with CdCl2 (4mg/Kg, once) with or without LBP pretreatment (300mg/Kg orally, once a day, for 30days). Testis weight, morphological/histological structure and oxidative stress parameters were evaluated. Several adverse effects were observed after CdCl2 injection, with a significant decrease in body/testis weight ratio (P<0.05), gross morphological changes with hyperemia of the parenchyma, increased volume and alteration in the structure of the seminiferous tubules...
June 20, 2017: Experimental and Molecular Pathology
https://www.readbyqxmd.com/read/28637871/phosphorylation-at-serine-31-targets-tyrosine-hydroxylase-to-vesicles-for-transport-along-microtubules
#9
Ana Jorge-Finnigan, Rune Kleppe, Kunwar Jung-Kc, Ming Ying, Michael Marie, Ivan Rios-Mondragon, Michael F Salvatore, Jaakko Saraste, Aurora Martinez
Tyrosine hydroxylase (TH) catalyzes the conversion of L-tyrosine into L-Dopa, which is the rate-limiting step in the synthesis of catecholamines, particularly dopamine in dopaminergergic neurons. Low dopamine levels and death of the dopaminergic neurons are hallmarks of Parkinson's disease (PD), where α-synuclein is also a key player. TH is highly regulated, notably by phosphorylation of several Ser/Thr residues in the N-terminal tail. However, the functional role of TH phosphorylation at the Ser31 site (THpSer31) remains unclear...
June 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28600214/validation-of-onchocerciasis-biomarker-n-acetyltyramine-o-glucuronide-natog
#10
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...
August 1, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28594102/the-inhibition-effects-of-some-natural-products-on-lactoperoxidase-purified-from-bovine-milk
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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 20, 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
#18
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
#19
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
#20
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
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