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https://www.readbyqxmd.com/read/29345916/monitoring-h2o2-inside-aspergillus-fumigatus-with-an-integrated-microelectrode-the-role-of-peroxiredoxin-protein-prx1
#1
Carla S Santos, Renata Bannitz-Fernandes, Alex S Lima, Carlos A Tairum, Iran Malavazi, Luis Eduardo S Netto, Mauro Bertotti
In vivo studies on the degradation of exogenous hydrogen peroxide (H2O2) in the microenvironment of Aspergillus fumigatus fungus were performed by using an integrated Pt microelectrode. Three A. fumigatus strains were used to confirm the role of the cytosolic protein Prx1 on the defense mechanism of this microorganism: a wild-type strain, capable to express the protein Prx1; a Δprx strain, whose gene prx1 was removed; and a complemented Δprx1::prx1+ strain derivatized from the Δprx and in which the gene prx1 was re-introduced...
January 18, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29345388/dentin-bond-strength-and-nanoleakage-of-the-adhesive-interface-after-intracoronal-bleaching
#2
Vanessa Cavalli, Maicon Sebold, Mirela Sanae Shinohara, Patrícia Nóbrega Rodrigues Pereira, Marcelo Giannini
This study evaluated dentin bond strength (BS) and nanoleakage of non- and pre-etched dentin immediately (T0 ,), 7 days (T7 ), and 14 days (T14 ) after bleaching. Bovine incisors (150) were selected and half of them submitted to intrapulpal dentin etching (e). Non- and pre-etched dentin were subjected to the following (n = 15): no bleaching/control (C); 35% carbamide peroxide (CP); 35% hydrogen peroxide (35% HP); 25% hydrogen peroxide (25% HP); and sodium perborate (SP). Bleaching agents were applied to the pulp chamber four times within a 72-h interval...
January 18, 2018: Microscopy Research and Technique
https://www.readbyqxmd.com/read/29345334/roles-of-the-three-mycobacterium-smegmatis-katg-genes-for-peroxide-detoxification-and-isoniazid-susceptibility
#3
Yasuhisa Iwao, Noboru Nakata
Three different katG sequences (katGI, katGII, and katGIII) were identified in the Mycobacterium smegmatis genome. The contribution of the three katG genes to survival of the bacterium was examined by constructing gene disruptants of these three genes. The katGIII sequence did not produce a functional catalase-peroxidase. Analyses of peroxidase activity and mRNA expression revealed that in wild type M. smegmatis, expression dominance between KatGI and KatGII was switched in the exponential growth phase and the stationary growth phase...
January 18, 2018: Microbiology and Immunology
https://www.readbyqxmd.com/read/29344877/a-bioluminescent-test-system-reveals-valuable-antioxidant-properties-of-lactobacillus-strains-from-human-microbiota
#4
Maria Marsova, Serikbay Abilev, Elena Poluektova, Valeriy Danilenko
Oxidative stress cause serious damages in human organism resulting in multiple diseases. Antioxidant therapy includes diet, the use of chemical agents or commensal bacteria such as lactobacilli. This study aims to evaluate the antioxidant (AO) activity of cell-free culture supernatants of lactobacilli, isolated from different parts of the human body. A test system based on Escherichia coli MG1655 strains carrying plasmids encoding luminescent biosensors pSoxS-lux and pKatG-lux inducible by superoxide anion and hydrogen peroxide, respectively, was used to analyze cell-free culture supernatants of lactobacilli...
January 17, 2018: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/29343643/pyridoxal-5-phosphate-as-an-oxygenase-cofactor-discovery-of-a-carboxamide-forming-%C3%AE-amino-acid-monooxygenase-decarboxylase
#5
Ying Huang, Xiaodong Liu, Zheng Cui, Daniel Wiegmann, Giuliana Niro, Christian Ducho, Yuan Song, Zhaoyong Yang, Steven G Van Lanen
Capuramycins are antimycobacterial antibiotics that consist of a modified nucleoside named uridine-5'-carboxamide (CarU). Previous biochemical studies have revealed that CarU is derived from UMP, which is first converted to uridine-5'-aldehyde in a reaction catalyzed by the dioxygenase CapA and subsequently to 5'-C-glycyluridine (GlyU), an unusual β-hydroxy-α-amino acid, in a reaction catalyzed by the pyridoxal-5'-phosphate (PLP)-dependent transaldolase CapH. The remaining steps that are necessary to furnish CarU include decarboxylation, O atom insertion, and oxidation...
January 17, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29342886/a-xylenol-orange-based-screening-assay-for-the-substrate-specificity-of-flavin-dependent-para-phenol-oxidases
#6
Tom A Ewing, Aster van Noord, Caroline E Paul, Willem J H van Berkel
Vanillyl alcohol oxidase (VAO) and eugenol oxidase (EUGO) are flavin-dependent enzymes that catalyse the oxidation of para-substituted phenols. This makes them potentially interesting biocatalysts for the conversion of lignin-derived aromatic monomers to value-added compounds. To facilitate their biocatalytic exploitation, it is important to develop methods by which variants of the enzymes can be rapidly screened for increased activity towards substrates of interest. Here, we present the development of a screening assay for the substrate specificity of para-phenol oxidases based on the detection of hydrogen peroxide using the ferric-xylenol orange complex method...
January 14, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29341384/influence-of-spore-and-carrier-material-surface-hydrophobicity-on-decontamination-efficacy-with-condensing-hydrogen-peroxide-vapor
#7
Elisabeth Eschlbeck, Christina Seeburger, Ulrich Kulozik
AIMS: To investigate the influence of surface hydrophobicity of carrier material and bacterial spores of Bacillus subtilis SA 22 and Bacillus atrophaeus (DSM 675) on spore inactivation with condensing hydrogen peroxide gas. METHODS AND RESULTS: Surface hydrophobicity of bacterial spores and carrier material was determined by means of contact angle measurement. Spores of Bacillus subtilis showed water contact angles of 90 °, spores of Bacillus atrophaeus showed water contact angles of 42 °...
January 16, 2018: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/29339757/melatonin-increases-chilling-tolerance-in-postharvest-peach-fruit-by-alleviating-oxidative-damage
#8
Shifeng Cao, Jiarong Shao, Liyu Shi, Liwei Xu, Ziming Shen, Wei Chen, Zhenfeng Yang
Melatonin has been reported to alleviate chilling symptoms in postharvest peach fruit during cold storage, however, the mechanism involved is largely unknown. To better understand its role in chilling tolerance, here we investigated the effects of melatonin on oxidative damage in peach fruit subjected to chilling after harvest. Chilling injury of peaches was dramatically reduced by melatonin treatment. Melatonin induced hydrogen peroxide (H2O2) content at the early stage of storage but inhibited its accumulation thereafter...
January 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29339453/pgrmc1-localization-and-putative-function-in-the-nucleolus-of-bovine-granulosa-cells-and-oocytes
#9
Laura Terzaghi, Alberto Maria Luciano, Priscila C Dall Acqua, Silvia Modina, John J Peluso, Valentina Lodde
Progesterone Receptor Membrane Component-1 (PGRMC1) is a highly conserved multifunctional protein that is found in numerous systems, including reproductive system. Interestingly, PGRMC1 is expressed at several intracellular locations, including the nucleolus. The aim of this study is to investigate the functional relationship between PGRMC1 and nucleolus. Immunofluorescence experiments confirmed PGRMC1's nucleolar localization in cultured bovine granulosa cells (bGC) and oocytes. Additional experiments conducted on bGC revealed that PGRMC1 co-localizes with nucleolin (NCL), a major nucleolar protein...
January 16, 2018: Reproduction: the Official Journal of the Society for the Study of Fertility
https://www.readbyqxmd.com/read/29339305/modelling-ros-formation-in-boreal-lakes-from-interactions-between-dissolved-organic-matter-and-absorbed-solar-photon-flux
#10
Raoul Wolf, Jan-Erik Thrane, Dag Olav Hessen, Tom Andersen
Concentrations of dissolved organic matter (DOM) are increasing in a large number of lakes across the Northern hemisphere. This browning serves a dual role for biota by protecting against harmful ultraviolet radiation, while also absorbing photosynthetically active radiation. The photochemical activation of DOM and subsequent formation of reactive oxygen species (ROS) is a potentially harmful side effect, but can be difficult to measure directly in situ. In this study, we combine a data set of physico-chemical properties from 71 Nordic lakes with in vitro ROS formation quantum yields to predict ROS formations across a representative boreal ecosystem gradient...
January 11, 2018: Water Research
https://www.readbyqxmd.com/read/29339217/effects-of-rutin-on-the-physicochemical-properties-of-skin-fibroblasts-membrane-disruption-following-uv-radiation
#11
Izabela Dobrzyńska, Agnieszka Gęgotek, Ewelina Gajko, Elżbieta Skrzydlewska, Zbigniew A Figaszewski
Human skin provides the body's first line of defense against physical and environmental assaults. This study sought to determine how rutin affects the membrane electrical properties, sialic acid content, and lipid peroxidation levels of fibroblast membranes after disruption by ultraviolet (UV) radiation. Changes in cell function may affect the basal electrical surface properties of cell membranes, and changes can be detected by electrokinetic measurements. The charge density of the fibroblast membrane surface was measured as a function of pH...
January 12, 2018: Chemico-biological Interactions
https://www.readbyqxmd.com/read/29337692/generation-of-superoxide-and-hydrogen-peroxide-by-side-reactions-of-mitochondrial-2-oxoacid-dehydrogenase-complexes-in-isolation-and-in-cells
#12
Victoria I Bunik, Martin D Brand
Mitochondrial 2-oxoacid dehydrogenase complexes oxidize 2-oxoglutarate, pyruvate, branched-chain 2-oxoacids and 2-oxoadipate to the corresponding acyl-CoAs and reduce NAD+ to NADH. The isolated enzyme complexes generate superoxide anion radical or hydrogen peroxide in defined reactions by leaking electrons to oxygen. Studies using isolated mitochondria in media mimicking cytosol suggest that the 2-oxoacid dehydrogenase complexes contribute little to the production of superoxide or hydrogen peroxide relative to other mitochondrial sites at physiological steady-states...
June 27, 2017: Biological Chemistry
https://www.readbyqxmd.com/read/29337589/critical-review-on-the-analytical-mechanistic-steps-in-the-evaluation-of-antioxidant-activity
#13
Anantharaman Shivakumar, M S Yogendra Kumar
Electrophysiological systems are prone to release free radicals for functioning of biological system with proper balancing of antioxidant-prooxidant ratio for establishing a healthy living system. The biostress condition releases different reactive oxygen species, such as hydroxyl, alkoxyl, superoxide, hydrogen peroxide, hydroperoxyl, ozone, singlet oxygen, hypochlorus acid, thiyl radical, etc. This review tries to discuss the general aspects of the antioxidant assay methodologies that are currently used for the detection of antioxidant property...
January 16, 2018: Critical Reviews in Analytical Chemistry
https://www.readbyqxmd.com/read/29337577/preparation-of-nano-au-pt-alloy-microspheres-decorated-with-reduced-graphene-oxide-for-non-enzymatic-hydrogen-peroxide-sensing
#14
Zhixue Bai, Wenhao Dong, Yipeng Ren, Cong Zhang, Qiang Chen
The flourish of nanotechnology has brought new vitality to the research and development of electrochemical sensing materials. In this work, we successfully synthesized Nano Au & Pt alloy microspheres decorated with reduced graphene oxide (RGO/nAPAMSs) by a simple, facile and eco-friendly one-step reduction strategy for the fabrication of highly sensitive non-enzymatic H2O2 sensing interfaces. Energy-dispersive X-ray spectroscopy mapping (EDX mapping), energy-dispersive X-ray spectroscopy analyzer (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR) and X-ray diffraction spectrum (XRD) were employed to characterize RGO/nAPAMSs from a microscopic perspective...
January 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29336940/myeloperoxidase-its-role-for-host-defense-inflammation-and-neutrophil-function
#15
REVIEW
Yasuaki Aratani
Myeloperoxidase (MPO) is a heme-containing peroxidase expressed mainly in neutrophils and to a lesser degree in monocytes. In the presence of hydrogen peroxide and halides, MPO catalyzes the formation of reactive oxygen intermediates, including hypochlorous acid (HOCl). The MPO/HOCl system plays an important role in microbial killing by neutrophils. In addition, MPO has been demonstrated to be a local mediator of tissue damage and the resulting inflammation in various inflammatory diseases. These findings have implicated MPO as an important therapeutic target in the treatment of inflammatory conditions...
January 11, 2018: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/29336721/using-hydrogen-peroxide-to-prevent-antibody-disulfide-bond-reduction-during-manufacturing-process
#16
Cheng Du, Yunping Huang, Ameya Borwankar, Zhijun Tan, Anthony Cura, Joon Chong Yee, Nripen Singh, Richard Ludwig, Michael Borys, Sanchayita Ghose, Nesredin Mussa, Zheng Jian Li
During large-scale monoclonal antibody manufacturing, disulfide bond reduction of antibodies, which results in generation of low molecule weight species, is occasionally observed. When this happens, the drug substance does not meet specifications. Many investigations have been conducted across the biopharmaceutical industry to identify the root causes, and multiple strategies have been proposed to mitigate the problem. The reduction is correlated with the release of cellular reducing components and depletion of dissolved oxygen before, during, and after harvest...
January 16, 2018: MAbs
https://www.readbyqxmd.com/read/29336033/h2-o2-mediates-nitrate-induced-iron-chlorosis-by-regulating-iron-homeostasis-in-rice
#17
Haifei Chen, Quan Zhang, Hongmei Cai, Wei Zhou, Fangsen Xu
The uptake of nitrate by plant roots causes a pH increment in rhizosphere and leads to iron (Fe) deficiency in rice. However, little is known about the mechanism how the nitrate uptake-induced high rhizosphere pH causes Fe deficiency. Here, we found that rice showed severe leaf chlorosis and large amounts of Fe plaque were aggregated on the root surface and intercellular space outside the exodermis in a form of ferrihydrite under alkaline conditions. In this case, there was significantly decreased Fe concentration in shoots and the Fe deficiency responsive genes were strongly induced in the roots...
January 16, 2018: Plant, Cell & Environment
https://www.readbyqxmd.com/read/29335171/effect-of-hydrogen-peroxide-on-microcystic-aeruginosa-role-of-cytochromes-p450
#18
Jia Wang, Zunwei Chen, Hui Chen, Yuezhong Wen
Cyanobacterial bloom has been rising as a worldwide issue owing to its adverse effects to water quality and ecological health. To solve this problem, hydrogen peroxide (H2O2) has been considered as a potential algaecide because no by-products are generated after treatment and because it kills cyanobacteria selectively. In addition, cytochromes P450 (CYPs) was reported to be related with H2O2, but the roles of CYPs in the regulation of H2O2 in cyanobacteria have yet to be investigated. In this study, the CYPs suicide inhibitor 1-aminobenzotriazole (ABT) was added to the representative cyanobacteria Microcystis aeruginosa (M...
January 12, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29334737/tubular-hybrids-a-nanoparticle-molecular-network
#19
Priyadarshi Ranjan, Sreejith Shankar, Ronit Popovitz-Biro, Sidney R Cohen, Iddo Pinkas, Reshef Tenne, Michal Lahav, Milko E van der Boom
We report here a new methodology for the formation of free-standing nanotubes composed of individual gold nanoparticles crosslinked by coordination complexes or porphyrin molecules using WS2 nanotubes (INT-WS2) as a template. Our method consists of three steps: (i) the coverage of these robust inorganic materials with monodispersed and dense monolayers of gold nanoparticles, (ii) formation of a molecular-AuNP network by exposing these decorated tubes to solutions containing a ruthenium polypyridyl complex or meso-tetra(4-pyridyl)porphyrin, (iii) removal of the INT-WS2 template with a hydrogen peroxide (H2O2) solution...
January 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29333855/carbon-and-binder-free-core-shell-nanowire-arrays-for-efficient-ethanol-electro-oxidation-in-alkaline-medium
#20
Fen Guo, Yiju Li, Baoan Fan, Yi Liu, Lilin Lu, Yang Lei
To achieve high electrochemical surface area (ECSA) and avoid carbon support and binder in the anode catalyst of direct ethanol fuel cell, herein, we design freestanding core-shell nickel@palladium-nickel nanowire arrays (Ni@Pd-Ni NAs) without carbon support and binder for high-efficiency ethanol electro-oxidation. Bare Ni nanowire arrays (Ni NAs) are first prepared using the facile template-assistantelectrodeposition method. Subsequently, the Ni@Pd-Ni NAs are formed using one-step solution-based alloying reaction...
January 15, 2018: ACS Applied Materials & Interfaces
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