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https://www.readbyqxmd.com/read/28930314/concerted-double-proton-transfer-electron-transfer-between-catechol-and-superoxide-radical-anion
#1
Jorge Quintero-Saumeth, David A Rincón, Markus Doerr, Martha C Daza
We have carried out a computational study on the reactivity of catechol (1,2-dihydroxybenzene) towards superoxide radical anion (O2˙(-)) in water, N,N-dimethylformamide (DMF), pentyl ethanoate (PEA) and vacuum using density functional theory and the coupled cluster method. Five reaction mechanisms were studied: (i) sequential proton transfer followed by hydrogen atom transfer (PT-HT), (ii) sequential hydrogen atom transfer followed by proton transfer (HT-PT), (iii) single electron transfer (SET), (iv) radical adduct formation (RAF) and (v) concerted double proton-transfer electron-transfer (denoted as global reaction, GR)...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28928973/prospective-replication-study-implicates-the-catechol-o-methyltransferase-val-158-met-polymorphism-as-a-biomarker-for-the-response-to-morphine-in-patients-with-cancer
#2
Hiromichi Matsuoka, Chihiro Makimura, Atsuko Koyama, Yoshihiko Fujita, Junji Tsurutani, Kiyohiro Sakai, Ryo Sakamoto, Kazuto Nishio, Kazuhiko Nakagawa
Genetic differences in humans cause clinical difficulties in opioid treatment. Previous studies indicate that a single nucleotide polymorphism in the catechol-O-methyltransferase (COMT) gene (rs4680; p.Val(158)Met) may present as a predictive biomarker for the response to morphine treatment. In our previous pilot exploratory study, patients with a G/G genotype were demonstrated to require a higher dose of morphine, compared with patients with A/A and A/G genotypes. In the present study, the aim was to replicate the findings in an independent cohort of opioid-treatment-naïve patients exhibiting various types of cancer...
October 2017: Biomedical Reports
https://www.readbyqxmd.com/read/28926717/multiple-metabolic-pathways-for-metabolism-of-l-tryptophan-in-i-fusarium-graminearum-i
#3
Kun Luo, Caro-Lyne DesRoches, Anne Johnston, Linda J Harris, Hui-Yan Zhao, Thérèse Ouellet
<i>Fusarium graminearum </i>is a plant pathogen that can cause the devastating cereal grain disease fusarium head blight (FHB) in temperate regions of the world. Previous studies have shown that <i>F. graminearum </i>can synthetize indole-3-acetic acid (auxin) using L-tryptophan (L-TRP)-dependent pathways. In the present study, we have taken a broader approach to examine the metabolism of L-TRP in <i>F. graminearum </i>liquid culture. Our results showed that <i>F. graminearum </i>was able to transiently produce the indole tryptophol when supplied with L-TRP...
September 19, 2017: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28923608/molecular-characterization-and-phylogenetic-analysis-of-highly-pathogenic-vibrio-alginolyticus-strains-isolated-during-mortality-outbreaks-in-cultured-ruditapes-decussatus-juvenile
#4
Badreddine Mechri, Monastiri Abir, Amel Medhioub, Mohamed Nejib Medhioub, Mahjoub Aouni
In the summer of 2008 and 2009, a series of mortalities in growing out seeds of R. decussatus juveniles were occurred in the eastern Tunisian littoral. Nine predominant bacterial strains were isolated from dead and moribund juveniles and characterized as Vibrio alginolyticus. These isolates were subjected to biochemical and molecular characterization. All the Vibrio strains were tested for their susceptibility against the most widely used antibiotic in aquaculture as well as, the assessment of the presence of erythromycin (emrB) and tetracycline (tetS) resistance genes among the tested bacteria...
September 15, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28921971/paper-sensor-coated-with-a-poly-carboxybetaine-multiple-dopa-conjugate-via-dip-coating-for-biosensing-in-complex-media
#5
Fang Sun, Kan Wu, Hsiang-Chieh Hung, Peng Zhang, Xinran Che, Joshua Kenyon Smith, Xiaojie Lin, Bowen Li, Priyesh Jain, Qiuming Yu, Shaoyi Jiang
Cellulose paper is an ideal diagnostic platform for low-cost, easily disposable and lightweight implementation, but requires surface modification to achieve detection with high sensitivity and specificity in complex media. In this work, a polymer-catechol conjugate containing a super-hydrophilic nonfouling poly(carboxylbetaine) (pCB) and four surface-binding L-3,4-dihydroxyphenylalanine (DOPA) groups, pCB-(DOPA)4, were applied onto a paper-based sensor surface via a simple "graft-to" immersion process to render the surface with both nonfouling and protein functionalizable properties...
September 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28918291/distinguished-cr-vi-capture-with-rapid-and-superior-capability-using-polydopamine-microsphere-behavior-and-mechanism
#6
Qingrui Zhang, Yixuan Li, Qinggang Yang, He Chen, Xinqing Chen, Tifeng Jiao, Qiuming Peng
Toxic heavy metal containing Cr(VI) species is a serious threat for ecological environment and human beings. In this work, a new mussel-inspired polydopamine microsphere (PDA-sphere) is prepared through in situ oxidative polymerization at air condition with controllable sizes. The adsorption of Cr(VI) ions onto PDA-sphere is highly pH dependent with the optimal pH ranging from 2.5 to 3.8. A rapid Cr(VI) removal can approach in 8min for equilibrium. More importantly, the prepared materials exhibit a remarkable sorption selectivity, coexisting SO4(2-), NO3(-) and Cl(-) ions at high levels; The applicability model further proves its effective performances with treated capacity of 42,000kg/kg sorbent, and the effluent can be reduced from 2000ppb to below 50ppb, which meets the drinking water criterions recommended by WHO...
August 26, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28916530/elucidation-of-the-impact-of-p-glycoprotein-and-breast-cancer-resistance-protein-on-the-brain-distribution-of-catechol-o-methyltransferase-inhibitors
#7
Joana Bicker, Ana Fortuna, Gilberto Alves, Patricio Soares-da-Silva, Amilcar Falcao
P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are clinically important efflux transporters that act cooperatively at the blood-brain barrier, limiting the entry of several drugs into the CNS and affecting their pharmacokinetics, therapeutic efficacy and safety. In the present study, the interactions of catechol-O-methyltransferase (COMT) inhibitors (BIA 9-1059, BIA 9-1079, entacapone, nebicapone, opicapone and tolcapone) with P-gp and BCRP were investigated in order to determine the contribution of these transporters in their access to the brain...
September 15, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28915025/structural-evidence-for-the-dopamine-first-mechanism-of-norcoclaurine-synthase
#8
Benjamin R Lichman, Altin Sula, Thomas Pesnot, Helen C Hailes, John M Ward, Nicholas H Keep
Norcoclaurine synthase (NCS) is a Pictet-Spenglerase that catalyzes the first key step in plant benzylisoquinoline alkaloid metabolism, a compound family that includes bioactive natural products such as morphine. The enzyme has also shown great potential as a biocatalyst for the formation of chiral isoquinolines. Here we present new high-resolution X-ray crystallography data describing Thalictrum flavum NCS bound to a mechanism-inspired ligand. The structure supports two key features of the NCS "dopamine-first" mechanism: the binding of dopamine catechol to Lys-122 and the position of the carbonyl substrate binding site at the active site entrance...
September 20, 2017: Biochemistry
https://www.readbyqxmd.com/read/28913946/facial-emotion-recognition-in-schizophrenia-an-exploratory-study-on-the-role-of-comorbid-alcohol-and-substance-use-disorders-and-comt-val158met
#9
Giuseppe Carrà, Gabriella Nicolini, Annamaria Lax, Francesco Bartoli, Filippo Castellano, Alessia Chiorazzi, Giulia Gamba, Mattia Bava, Cristina Crocamo, Costanza Papagno
OBJECTIVES: To explore whether facial emotion recognition (FER), impaired in both schizophrenia and alcohol and substance use disorders (AUDs/SUDs), is additionally compromised among comorbid subjects, also considering the role of catechol-O-methyltransferase (COMT) Val158Met. METHODS: We conducted a cross-sectional study, randomly recruiting 67 subjects with a DSM-IV-TR diagnosis of schizophrenia, and rigorously assessing AUDs/SUDs and COMT Val158Met polymorphism...
September 15, 2017: Human Psychopharmacology
https://www.readbyqxmd.com/read/28910078/bifacial-biomimetic-freestanding-anisotropic-catechol-interfaces-with-asymmetrically-layered-films-as-versatile-extracellular-matrix-substitutes
#10
Byung Gee Im, Minjae Do, Yoojin Kim, Mira Cho, Jae-Hyung Jang
Biological naïve extracellular matrices (ECMs) exhibit anisotropic functions in their physical, chemical, and morphological properties. Representative examples include anisotropic skin layers or blood vessels simultaneously facing multiphasic environments. Here, anisotropically multifunctional structures called BiFACIAL (biomimetic freestanding anisotropic catechol-interfaces with asymmetrically layered) films were developed simply by contacting two polysaccharide solutions of heparin-catechol (Hep-C) and chitosan-catechol (Chi-C)...
September 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28905618/functionalization-of-reduced-graphene-oxide-via-thiol-maleimide-click-chemistry-facile-fabrication-of-targeted-drug-delivery-vehicles
#11
Yavuz Oz, Alexandre Barras, Rana Sanyal, Rabah Boukherroub, Sabine Szunerits, Amitav Sanyal
Reduced graphene oxide (rGO) based materials have shown to be amenable to non-covalent functionalization through hydrophobic interactions. The scaffold however does not provide sufficient covalent linkage given the low number of reactive carboxyl and alcohol groups typically available on rGO. The integration of clickable groups, particularly ones which can undergo efficient conjugation without any metal catalyst, would allow facile functionalization of these materials. This study reports on the non-covalent association of a maleimide-containing catechol (dopa-MAL) surface anchor onto rGO...
September 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28904061/a-randomized-controlled-trial-of-green-tea-extract-supplementation-and-mammographic-density-in-postmenopausal-women-at-increased-risk-of-breast-cancer
#12
Hamed Samavat, Giske Ursin, Tim H Emory, Eunjung Lee, Renwei Wang, Carolyn J Torkelson, Allison M Dostal, Karen Swenson, Chap T Le, Chung S Yang, Mimi C Yu, Douglas Yee, Anna H Wu, Jian-Min Yuan, Mindy S Kurzer
Epidemiological and animal studies suggest a protective role of green tea against breast cancer. However the underlying mechanism is not understood. We conducted a randomized, double-blinded, placebo-controlled phase II clinical trial to investigate whether supplementation with green tea extract (GTE) modifies mammographic density (MD), as a potential mechanism, involving 1,075 healthy postmenopausal women. Women assigned to the treatment arm consumed daily 4 decaffeinated GTE capsules containing 1315 mg total catechins including 843 mg epigallocatechin-3-gallate (EGCG) for 12 months...
September 13, 2017: Cancer Prevention Research
https://www.readbyqxmd.com/read/28901273/oleuropein-molecular-dynamics-and-computation
#13
Luigi Gentile, Nicola A Uccella, Ganapathy Sivakumar
Olive oil and table olive biophenols have been shown to significantly enrich the hedonic-sensory and nutritional quality of the Mediterranean diet. Oleuropein is one of the predominate biophenols in green olives and leaves, which not only has noteworthy free-radical quenching activity but also putatively reduces the incidence of various cancers. Clinical trials suggest that the consumption of extra virgin olive oil reduces the risk of several degenerative diseases. The oleuropein-based bioactives in olive oil could reduce tumor necrosis factor α, interleukin-1β and nitric oxide...
September 11, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28900390/genetically-driven-enhancement-of-dopaminergic-transmission-affects-moral-acceptability-in-females-but-not-in-males-a-pilot-study
#14
Silvia Pellegrini, Sara Palumbo, Caterina Iofrida, Erika Melissari, Giuseppina Rota, Veronica Mariotti, Teresa Anastasio, Andrea Manfrinati, Rino Rumiati, Lorella Lotto, Michela Sarlo, Pietro Pietrini
Moral behavior has been a key topic of debate for philosophy and psychology for a long time. In recent years, thanks to the development of novel methodologies in cognitive sciences, the question of how we make moral choices has expanded to the study of neurobiological correlates that subtend the mental processes involved in moral behavior. For instance, in vivo brain imaging studies have shown that distinct patterns of brain neural activity, associated with emotional response and cognitive processes, are involved in moral judgment...
2017: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/28899792/evidence-for-non-linear-metabolism-at-low-benzene-exposures-a-reanalysis-of-data
#15
K McNally, C Sams, G D Loizou, K Jones
The presence of a high-affinity metabolic pathway for low level benzene exposures of less than one part per million (ppm) has been proposed although a pathway has not been identified. The variation of metabolite molar fractions with increasing air benzene concentrations was suggested as evidence of significantly more efficient benzene metabolism at concentrations <0.1 ppm The evidence for this pathway is predicated on a rich data set from a study of Chinese shoe workers exposed to a wide range of benzene concentrations (not just "low level")...
September 9, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/28898548/plasma-catechols-after-eating-olives
#16
David S Goldstein, Courtney Holmes, Jamie Cherup, Yehonatan Sharabi
Olives contain 3,4-dihydroxyphenyl compounds (catechols)-especially 3,4-dihydroxyphenylethanol (DOPET)-that have therapeutic potential as nutraceuticals. Whether olive ingestion affects plasma levels of free (unconjugated) catechols has been unknown. Arm venous blood was sampled before and 15, 30, 45, 60, 120, 180, and 240 min after six healthy volunteers ate 10 Kalamata olives. Catechols were assayed by alumina extraction followed by liquid chromatography with series electrochemical detection. Plasma DOPET increased to 18...
September 12, 2017: Clinical and Translational Science
https://www.readbyqxmd.com/read/28895596/electrochemical-estimation-of-the-active-site-density-on-metal-free-nitrogen-doped-carbon-using-catechol-as-an-adsorbate
#17
Arup Chakraborty, Ruttala Devivaraprasad, Bapi Bera, Manoj Neergat
Carbon is heat-treated with a nitrogen-containing precursor (ammonia) to obtain nitrogen-doped carbon and the composition is estimated using CHN and XPS analysis. The active site density of the carbon and nitrogen-doped carbon is quantified using 1,2-dihydroxybenzene (catechol) molecules as an adsorbate in phosphate buffer (pH 7) solution. The features of the voltammograms of the catechol-adsorbed high surface area carbon and nitrogen-doped carbon are similar to that of the polished nitrogen-grafted glassy carbon electrode (GCE) reported in the literature...
September 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28893069/silicone-oil-swelling-slippery-surfaces-based-on-mussel-inspired-magnetic-nanoparticles-with-multiple-self-healing-mechanisms
#18
Biyu Jin, Mingzhu Liu, Qinghua Zhang, Xiaoli Zhan, Fengqiu Chen
In this work, a novel substrate building block, magnetic Fe3O4 nanoparticles (MNPs) armed with dopamine molecules were developed via mussel-inspired metal-coordination bonds. Combined with glycidyl methacrylate, polydimethylsiloxane (PDMS) and diethylenetriamine (DETA), the original silicone oil swelling SLIPS (SPG-MNP) owning ability to heal the matrix itself were first prepared by reversible coordinate bonds and strong covalent bonds crosslinking process. The matrix mechanical characteristics and surface physicochemical properties were also systematically investigated...
September 11, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28891646/synergic-click-boronate-thiosemicarbazone-system-for-fast-and-irreversible-bioorthogonal-conjugation-in-live-cells
#19
Burcin Akgun, Caishun Li, Yubin Hao, Gareth Lambkin, Ratmir Derda, Dennis G Hall
Fast, high-yielding and selective bioorthogonal 'click' reactions employing non-toxic reagents are in high demand for their great utility in the bioconjugation of biomolecules in live cells. Although a number of click reactions were developed for this purpose, many are associated with drawbacks and limitations that justify the development of alternative systems for both single- or dual-labeling applications. Recent reports highlighted the potential of boronic ester formation as a bioorthogonal click reaction between abiotic boronic acids and diols...
September 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28890256/tuneable-denture-adhesives-using-biomimetic-principles-for-enhanced-tissue-adhesion-in-moist-environments
#20
Simrone K Gill, Nima Roohpour, Paul D Topham, Brian J Tighe
Nature provides many interesting examples of adhesive strategies. Of particular note, the protein glue secreted by marine mussels delivers high adhesion in wet and dynamic environments owing to existence of catechol moieties. As such, this study focuses on denture fixatives, where a non-zinc-containing commercial-based formulation has been judiciously modified by a biomimetic catechol-inspired polymer, poly(3,4-dihydroxystyrene/styrene-alt-maleic acid) in a quest to modulate adhesive performance. In vitro studies, in a lap-shear configuration, revealed that the catechol-modified components were able to enhance adhesion to both the denture base and hydrated, functional oral tissue mimic, with the resulting mode of failure prominently being adhesive rather than cohesive...
September 7, 2017: Acta Biomaterialia
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