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https://www.readbyqxmd.com/read/29777681/electrochemical-enzymatic-fenitrothion-sensor-based-on-a-tyrosinase-poly-2-hydroxybenzamide-modified-graphite-electrode
#1
Maria de Fátima Alves, Ricardo Augusto Moreira de Souza Corrêa, Filipe Soares da Cruz, Diego Leoni Franco, Lucas Franco Ferreira
This paper reports the electrosynthesis and characterisation of a polymeric film derived from 2-hydroxybenzamide over a graphite electrode and its application as an enzymatic biosensor for the determination and quantification of the pesticide fenitrothion. The material was analysed by scanning electron microscopy and its electrochemical properties characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The enzyme tyrosinase was immobilised over the modified electrode by the drop and dry technique...
May 16, 2018: Analytical Biochemistry
https://www.readbyqxmd.com/read/29775200/cadmium-induced-changes-in-the-production-of-siderophores-by-a-plant-growth-promoting-strain-of-pseudomonas-fulva
#2
Dominika Thiem, Michał Złoch, Renata Gadzała-Kopciuch, Sonia Szymańska, Christel Baum, Katarzyna Hrynkiewicz
The impact of increasing Cd2+ exposure on the quality and quantity of siderophores produced by a plant growth promoting Pseudomonas fulva strain was tested to gain insight into the degree of change. P. fulva was cultured in the increasing concentrations of Cd2+ (0, 0.5, 1.0, 2.0 mM). The secreted siderophores were separated by HPLC and characterized by UHPLC-QTOF/MS. In the presence of 2 mM Cd2+ synthesis of siderophores (hydroxamates, catecholates, phenolates) was mitigated compared to the treatments with lower concentrations of Cd2+ (0...
May 18, 2018: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/29762479/development-of-a-polyphenol-oxidase-biosensor-from-jenipapo-fruit-extract-genipa-americana-l-and-determination-of-phenolic-compounds-in-textile-industrial-effluents
#3
Rafael Souza Antunes, Denes Ferraz, Luane Ferreira Garcia, Douglas Vieira Thomaz, Rafael Luque, Germán Sanz Lobón, Eric de Souza Gil, Flávio Marques Lopes
In this work, an innovative polyphenol oxidase biosensor was developed from Jenipapo ( Genipa americana L.) fruit and used to assess phenolic compounds in industrial effluent samples obtained from a textile industry located in Jaraguá-GO, Brasil. The biosensor was prepared and optimized according to: the proportion of crude vegetal extract, pH and overall voltammetric parameters for differential pulse voltammetry. The calibration curve presented a linear interval from 10 to 310 µM (r² = 0.9982) and a limit of detection of 7 µM...
May 15, 2018: Biosensors
https://www.readbyqxmd.com/read/29761656/a-two-step-process-for-the-synthesis-of-hydroxytyrosol
#4
Ziosi Paolo, Paolucci Claudio, Santarelli Francesco, Tabanelli Tommaso, Passeri Sauro, Fabrizio Cavani, Righi Paolo
Here we report about a new process for the synthesis of hydroxytyrosol (3,4-dihydroxyphenylethanol), the most powerful natural antioxidant currently known, by means of a two-step approach. Catechol is first reacted with 2,2 dimethoxyacetaldehyde in basic aqueous medium, to produce the corresponding mandelic derivative with > 90% conversion of the limiting reactant and about 70% selectivity to the desired para-hydroxyalkylated compound. Thereafter, the intermediate is hydrogenated to hydroxytyrosol using a Pd/C catalyst, with total conversion of the mandelic derivative and 68% selectivity...
May 14, 2018: ChemSusChem
https://www.readbyqxmd.com/read/29760667/a-drd2-annk1-comt-interaction-consisting-of-functional-variants-confers-risk-of-post-traumatic-stress-disorder-in-traumatized-chinese
#5
Kunlin Zhang, Li Wang, Chengqi Cao, Gen Li, Ruojiao Fang, Ping Liu, Shu Luo, Xiangyang Zhang, Israel Liberzon
Objective: Post-traumatic stress disorder (PTSD) is a trauma- and stress-related psychiatric syndrome that occurs after exposure to extraordinary stressors. The neurotransmitter dopamine (DA) plays important roles in neurobiological processes like reward and stress, and a link between PTSD and the dopaminergic system has been reported. Thus, the investigation of an association between PTSD and gene-gene interaction (epistasis) within dopaminergic genes could uncover the genetic basis of dopamine-related PTSD symptomatology and contribute to precision medicine...
2018: Frontiers in Psychiatry
https://www.readbyqxmd.com/read/29757607/dual-ph-responsive-shell-cleavable-polycarbonate-micellar-nanoparticles-for-in-vivo-anticancer-drug-delivery
#6
Shaoqiong Liu, Robert Ono, Chuan Yang, Shujun Gao, Jordan Tan, James L Hedrick, Yi Yan Yang
To exploit tumor and intracellular microenvironments, pH-responsive diblock copolymers of PEG and catechol-functionalized polycarbonate with acid-labile acetal bond as the linker are synthesized to prepare micellar nanoparticles that shed the shell at acidic tumor tissues and inside cancer cells, hence accelerating drug release at the target. The pH-dependent cleavage of the shell is demonstrated at pH 5.0 and 6.5 using GPC and 1H NMR. Bortezomib (BTZ, an anticancer drug containing a phenylboronic acid group) is conjugated to the polymers through formation of pH-responsive boronate ester bond between boronic acid and cetachol in the polymers...
May 14, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29751654/biodegradation-of-di-2-ethylhexyl-phthalate-by-rhodococcus-ruber-yc-yt1-in-contaminated-water-and-soil
#7
Ting Yang, Lei Ren, Yang Jia, Shuanghu Fan, Junhuan Wang, Jiayi Wang, Ruth Nahurira, Haisheng Wang, Yanchun Yan
Di-(2-ethylehxyl) phthalate (DEHP) is one of the most broadly representative phthalic acid esters (PAEs) used as a plasticizer in polyvinyl chloride (PVC) production, and is considered to be an endocrine-disrupting chemical. DEHP and its monoester metabolites are responsible for adverse effects on human health. An efficient DEHP-degrading bacterial strain Rhodococcus ruber YC-YT1, with super salt tolerance (0⁻12% NaCl), is the first DEHP-degrader isolated from marine plastic debris found in coastal saline seawater...
May 11, 2018: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29750865/surface-modification-with-a-catechol-bearing-polypeptide-and-sensing-applications
#8
Eda Aydindogan, Emine Guler Celik, Dilek Odaci Demirkol, Shuhei Yamada, Takeshi Endo, Suna Timur, Yusuf Yagci
A novel catechol bearing polypeptide (CtP) was synthesized and used as a component of electrochemical biosensor involving both enzymatic activity and affinity-based sensing systems. Glucose oxidase (GOx) and Anti-Immunoglobulin G (Anti-IgG) were selected as model biorecognition elements for the selective analysis of glucose and IgG. Step by step surface modifications were followed using various techniques such as cyclic voltammetry (CV) and electrochemical impedance spectrometry (EIS) as well as X-Ray photoelectron spectroscopy (XPS)...
May 11, 2018: Biomacromolecules
https://www.readbyqxmd.com/read/29745764/influence-of-polydopamine-mediated-surface-modification-on-oxygen-release-capacity-of-haemoglobin-based-oxygen-carriers
#9
Quan Wang, Ruirui Zhang, Guoxing You, Jilin Hu, Penglong Li, Ying Wang, Jun Zhang, Yan Wu, Lian Zhao, Hong Zhou
Oxidative toxicity has impeded the development of haemoglobin-based oxygen carriers (HBOCs) by causing methaemoglobin (MetHb) formation and inducing oxidative stress. In our previous work, polydopamine-coated haemoglobin (Hb-PDA) nanoparticles have been designed and synthesized with the capacity to reduce oxidative toxicity. In this investigation, the mass ratio of dopamine (DA) to haemoglobin (Hb) and the pH value are found to be the primary factors that influence preparation of Hb-PDA nanoparticles. X-ray photoelectron spectroscopy showed that the catechol groups of DA play a crucial role in the modification of Hb surface...
May 10, 2018: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/29745566/-research-progress-of-neurobiological-function-of-1-methyl-6-7-dihydroxy-1-2-3-4-tetrahydroisoquinoline
#10
REVIEW
Xiaotong Zheng, Xuechai Chen, Zixuan Chen, Hong Qing, Yulin Deng, Rugang Zhong, Minjun Guo
1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (Sal) is a kind of catechol isoquinoline compound, which mainly exists in mammalian brain and performs a variety of biological functions. Through in vivo metabolism, Sal can be transformed into endogenous neurotoxins and can participate the occurrence of Parkinson's disease (PD). This has attracted widespread concern of researchers. Recently, many research works have shown that Sal may lead to alcohol addiction and regulate hormone release of the neuroendocrine system, which indicated that it is a potential regulator of dopaminergic neurons...
June 1, 2017: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
https://www.readbyqxmd.com/read/29744443/incorporating-catechol-into-electroactive-polypyrrole-nanowires-on-titanium-to-promote-hydroxyapatite-formation
#11
Zhengao Wang, Jinquan Zeng, Guoxin Tan, Jingwen Liao, Lei Zhou, Junqi Chen, Peng Yu, Qiyou Wang, Chengyun Ning
To improve the osteointegration property of biomedical titanium, nano-architectured electroactive coating was synthesized through the electrochemical polymerization of dopamine and pyrrole. The highly binding affinity of Ca2+ to the catechol moiety of doped dopamine enabled efficient interaction between polypyrrole/polydopamine nanowires and mineral ions. The results indicate that the PPy/PDA nanowires preserved its efficient electro-activity and accelerated the hydroxyapatite deposition in a simulated body fluid...
March 2018: Bioactive Materials
https://www.readbyqxmd.com/read/29740575/hydroxybenzoic-acid-derivatives-as-dual-target-ligands-mitochondriotropic-antioxidants-and-cholinesterase-inhibitors
#12
Catarina Oliveira, Fernando Cagide, José Teixeira, Ricardo Amorim, Lisa Sequeira, Francesco Mesiti, Tiago Silva, Jorge Garrido, Fernando Remião, Santiago Vilar, Eugenio Uriarte, Paulo J Oliveira, Fernanda Borges
Alzheimer's disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy toward AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN 1 (catechol derivative), and AntiOxBEN 2 (pyrogallol derivative) and compounds 15-18 , which have longer spacers...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29738234/coating-titania-nanoparticles-with-epoxy-containing-catechol-polymers-via-cu-0-lrp-as-intelligent-enzyme-carriers
#13
Donghao Wang, Wenyi Ding, Kaiyue Zhou, Shutong Guo, Qiang Zhang, David M Haddleton
Immobilization of enzyme could offer the biocatalyst with increased stability and important recoverability, which plays a vital role for the enzyme's industrial applications. In this study, we present a new strategy to build an intelligent enzyme carrier by coating titania nanoparticles with thermoresponsive epoxy-functionalized polymers. Zero-valent copper mediated living radical polymerization (Cu(0)-LRP) was utilized herein to copolymerize N-isopropylacrylamide (NIPAM) and glycidyl acrylate (GA), directly from an unprotected dopamine-functionalized initiator, in order to obtain an epoxy-containing polymer with terminal anchor for the "grafting to" or "one-pot" modification of titania nanoparticles...
May 8, 2018: Biomacromolecules
https://www.readbyqxmd.com/read/29733501/a-versatile-mussel-inspired-dynamic-biointerface-from-specific-cell-behavior-modulation-to-selective-cell-isolation
#14
Lei Liu, Xiaohua Tian, Yue Ma, Yuqing Duan, Xin Zhao, Guoqing Pan
We report here a novel dynamic biointerface based on mussel-inspired chemistry and reversible covalent chemistry. We first biomimetically designed peptides with catechol-containing sequence and cell-binding sequence at each end. The biomimetic, mussel-inspired peptides were then reversibly bound on a phenylboronic acid (PBA)-containing polymer-grafted substrate through sugar-responsive catechol-boronate covalent interactions. The resultant biointerface is thus capable of dynamic presentation of the bioactivity (i...
May 7, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29732734/io4-stimulated-crosslinking-of-catechol-conjugated-hydroxyethyl-chitosan-as-a-tissue-adhesive
#15
Xiaoting Peng, Yanfei Peng, Baoqin Han, Wanshun Liu, Fuming Zhang, Robert J Linhardt
Catechol-functionalized polymers are of particular interest because of their strong water-resistant adhesive properties. Hydroxymethyl chitosan (HECTS) has been used as an implantable biomaterial having good water solubility, biodegradability and biocompatibility. Here, hydrocaffeic acid (HCA) grafted HECTS (HCA-g-HECTS) was prepared through carbodiimide coupling and the tethered catechol underwent periodate (IO4-)-stimulated mono and double cross-linking with genipin. The gelation time of these cross-linked HCA-g-HECTS hydrogels decreased with increasing molar ratio of cross-linker to grafted catechol group, increasing temperature, or the addition of genipin...
May 7, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/29732328/spectrophotometric-techniques-for-the-characterization-of-strains-involved-in-the-blue-pigmentation-of-food-preliminary-results
#16
Luca Fasolato, Nadia Andrea Andreani, Roberta De Nardi, Giulia Nalotto, Lorenzo Serva, Barbara Cardazzo, Stefania Balzan, Lisa Carraro, Federico Fontana, Enrico Novelli
Near infrared spectroscopy (NIRs) and ultraviolet visible spectroscopy (UV-vis) have been investigated as rapid techniques to characterize foodborne bacteria through the analysis of the spectra of whole cells or microbial suspensions. The use of spectra collected from broth cultures could be used as a fingerprint for strain classification using a combined polyphasic approach. The aim of this study was to evaluate the feasibility of NIRs and UV-vis for the characterization of blue strains belonging to the Pseudomonas fluorescens group...
March 31, 2018: Italian Journal of Food Safety
https://www.readbyqxmd.com/read/29730044/association-between-catechol-o-methyltransferase-genetic-variation-and-functional-connectivity-in-patients-with-first-episode-schizophrenia
#17
Hongyan Wang, Bin Zhang, Botao Zeng, Yingying Tang, Tianhong Zhang, Shanshan Zhao, Chunbo Li, Jijun Wang, Donald C Goff
Dopamine in the prefrontal cortex (PFC) plays an important role in cognitive performance and regulates by catechol-O-methyltransferase (COMT) expression. To clarify the effect of COMT genotype on cognitive function in patients with schizophrenia, we performed DNA genotyping, cognitive evaluations, and functional magnetic resonance imaging (fMRI) in antipsychotic-naïve patients with first-episode schizophrenia (FES) and matched healthy control subjects. We found that all cognitive domains were impaired in patients with FES compared with healthy subjects...
May 3, 2018: Schizophrenia Research
https://www.readbyqxmd.com/read/29723539/differential-effect-of-comt-gene-methylation-on-the-prefrontal-connectivity-in-subjects-with-depression-versus-healthy-subjects
#18
Kyoung-Sae Na, Eunsoo Won, June Kang, Aram Kim, Sunyoung Choi, Woo-Suk Tae, Yong-Ku Kim, Min-Soo Lee, Sook-Haeng Joe, Byung-Joo Ham
Expression of the catechol-O-methyl transferase (COMT) gene mainly determines prefrontal dopaminergic availability. Deficient prefrontal dopaminergic activity leads to loss of interest, energy, and motivation, which are core symptoms of depression. Given the role of stress-environmental interactions in major depressive disorder (MDD), we investigated the impact of COMT gene methylation status on prefrontal connectivity. We measured COMT gene methylation and polymorphisms (Val158Met) at the rs4468 locus in peripheral blood samples of healthy controls (n = 90) and patients with MDD (n = 90)...
April 30, 2018: Neuropharmacology
https://www.readbyqxmd.com/read/29717427/design-of-ag-and-pt-tio-2-sio-2-nanomaterials-for-the-photocatalytic-degradation-of-phenol-under-solar-irradiation
#19
Juan Matos, Biviana Llano, Ricmary Montaña, Po S Poon, Maria C Hidalgo
The design of hybrid mesoporous TiO2 -SiO2 (TS1) materials decorated with Ag and Pt nanoparticles was performed. The photocatalytic degradation of phenol under artificial solar irradiation was studied and the activity and selectivity of the intermediate products were verified. TiO2 -SiO2 was prepared by sol-gel method while Ag- and Pt-based photocatalysts (TS1-Ag and TS1-Pt) were prepared by photodeposition of the noble metals on TS1. Two series of photocatalysts were prepared varying Ag and Pt contents (0...
May 1, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29715329/a-new-crystal-form-of-aspergillus-oryzae-catechol-oxidase-and-evaluation-of-copper-site-structures-in-coupled-binuclear-copper-enzymes
#20
Leena Penttinen, Chiara Rutanen, Markku Saloheimo, Kristiina Kruus, Juha Rouvinen, Nina Hakulinen
Coupled binuclear copper (CBC) enzymes have a conserved type 3 copper site that binds molecular oxygen to oxidize various mono- and diphenolic compounds. In this study, we found a new crystal form of catechol oxidase from Aspergillus oryzae (AoCO4) and solved two new structures from two different crystals at 1.8-Å and at 2.5-Å resolutions. These structures showed different copper site forms (met/deoxy and deoxy) and also differed from the copper site observed in the previously solved structure of AoCO4. We also analysed the electron density maps of all of the 56 CBC enzyme structures available in the protein data bank (PDB) and found that many of the published structures have vague copper sites...
2018: PloS One
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