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https://www.readbyqxmd.com/read/28098843/perm-hypothesis-the-fundamental-machinery-able-to-elucidate-the-role-of-xenobiotics-and-hormesis-in-cell-survival-and-homeostasis
#1
REVIEW
Salvatore Chirumbolo, Geir Bjørklund
In this article the Proteasome, Endoplasmic Reticulum and Mitochondria (PERM) hypothesis is discussed. The complex machinery made by three homeostatic mechanisms involving the proteasome (P), endoplasmic reticulum (ER) and mitochondria (M) is addressed in order to elucidate the beneficial role of many xenobiotics, either trace metals or phytochemicals, which are spread in the human environment and in dietary habits, exerting their actions on the mechanisms underlying cell survival (apoptosis, cell cycle regulation, DNA repair and turnover, autophagy) and stress response...
January 15, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28098402/anion-%C3%AF-interactions-in-flavoproteins-involve-a-substantial-charge-transfer-component
#2
Jiri Kozelka, Yevgen Yurenko, Sophia Bazzi, Radek Marek
Anion-π interactions have been shown to stabilize flavoproteins and to regulate the redox potential of the flavin cofactor. They are commonly attributed to electrostatic forces. Here we show that anion-flavin interactions have a substantial charge-transfer component. Our conclusion emanates from a multiapproach theoretical analysis and is backed by previously reported observations of absorption bands, originating from charge transfer between oxidized flavin and proximate cystein thiolate groups. This partial covalency of anion-flavin contacts renders classical simulations of flavoproteins questionable...
January 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28098314/isoindoline-nitroxide-labeled-porphyrins-as-potential-fluorescence-suppressed-spin-probes
#3
F Liu, T J Zou, Z L Tan, S Chen, Z H Wu, G P Yan, Q Zhang, S C Liang, J Yang
A series of isoindoline nitroxide-labeled porphyrins were synthesized by the reaction of 5-phenyldipyrromethane and 5-(4'-carboethoxy-methyleneoxyphenyl)dipyrromethane with 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO) using the Lindsey method. The corresponding water-soluble spin-labeled porphyrins were also prepared. Subsequently, these compounds were characterized and their in vitro properties were evaluated. The electrochemical assay demonstrated that these isoindoline nitroxide-labeled porphyrins had similar electrochemical and redox properties to 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO)...
January 18, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28098177/an-extended-n-h-bond-driven-by-a-conserved-second-order-interaction-orients-the-flavin-n5-orbital-in-cholesterol-oxidase
#4
Emily Golden, Li-Juan Yu, Flora Meilleur, Matthew P Blakeley, Anthony P Duff, Amir Karton, Alice Vrielink
The protein microenvironment surrounding the flavin cofactor in flavoenzymes is key to the efficiency and diversity of reactions catalysed by this class of enzymes. X-ray diffraction structures of oxidoreductase flavoenzymes have revealed recurrent features which facilitate catalysis, such as a hydrogen bond between a main chain nitrogen atom and the flavin redox center (N5). A neutron diffraction study of cholesterol oxidase has revealed an unusual elongated main chain nitrogen to hydrogen bond distance positioning the hydrogen atom towards the flavin N5 reactive center...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28097871/redox-responsive-self-assembly-micelles-from-poly-n-acryloylmorpholine-block-2-acryloyloxyethyl-ferrocene-carboxylate-amphiphilic-block-copolymers-as-drug-release-carriers
#5
Feng Xu, He Li, Yan-Ling Luo, Wei Tang
Novel well-defined redox-responsive ferrocene-containing amphiphilic block copolymers (PACMO-b-PAEFC) were synthesized by ATRP, with poly(N-acryloylmorpholine) (PACMO) as hydrophilic blocks and poly(2-acryloyloxyethyl ferrocenecarboxylate) (PAEFC) as hydrophobic blocks. The copolymers were characterized by FTIR, 1H NMR, and gel permeation chromatography, and the crystalline behavior was determined by X-ray diffraction and small-angle X-ray scattering. The results showed that the size of the lamellar crystals and crystallinity vary with the systematic compositions while the periodic structure of the lamellar stacks has no obvious change...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28097797/an-asymmetric-redox-arylation-chirality-transfer-from-sulfur-to-carbon-through-a-sulfonium-3-3-sigmatropic-rearrangement
#6
Dainis Kaldre, Boris Maryasin, Daniel Kaiser, Oliver Gajsek, Leticia González, Nuno Maulide
A general, asymmetric redox arylation of ynamides and thioalkynes with chiral sulfoxides is reported. This is the first example of a general 1,4-chirality transfer from sulfur to a carbon stereocenter through a sulfonium [3,3]-sigmatropic rearrangement. This reaction delivers α-arylated thioesters and amides under mild conditions in an atom-economical manner. The products are formed in high yields with enantiomeric ratios up to 99.5:0.5. Quantum chemical calculations suggest a mechanism for the chirality transfer from sulfur to carbon and explain the experimentally observed correlation of the enantioselectivity with both the catalyst and the substrate...
January 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28097790/visible-light-mediated-remote-aliphatic-c-h-functionalizations-through-a-1-5-hydrogen-transfer-cascade
#7
Wei Shu, Cristina Nevado
A redox-neutral, light-mediated functionalization of unactivated C(sp(3) )-H bonds via iminyl radicals is presented here. A 1,5-H transfer followed by the functionalization of a C(sp(2) )-H bond takes place in aqueous media producing a variety of elaborated fused ketones. Mechanistic investigations have revealed 1,5-H transfer as the reversible, rate-determining step in this transformation. Divergent scaffolds are also accessible via C(sp(3) )-N bond formation upon a careful choice of the reaction additives...
January 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28097517/in-utero-exposure-of-hyperlipidemic-mice-to-diesel-exhaust-lack-of-effects-on-atherosclerosis-in-adult-offspring-fed-a-regular-chow-diet
#8
Jenna Harrigan, Divya Ravi, Jerry Ricks, Michael E Rosenfeld
Uterine stress is associated with an increased risk of later life metabolic diseases. In this study, we investigated the effect of diesel exhaust (DE) exposure in utero on adult susceptibility to atherosclerosis in genetically hyperlipidemic mice. Pregnant apolipoprotein E-deficient mice received either DE exposure (~250-300 μg/m(3) PM2.5 for 6 h/day, 5 days/week) or filtered air (FA) throughout gestation. Treatment effects on litter size and gender distribution were recorded. Plasma cholesterol and triglycerides were measured at 8, 12 and 16 weeks of age...
January 17, 2017: Cardiovascular Toxicology
https://www.readbyqxmd.com/read/28097376/elemental-labelling-and-mass-spectrometry-for-the-specific-detection-of-sulfenic-acid-groups-in-model-peptides-a-proof-of-concept
#9
Mona Sharar, Essa M Saied, Mario C Rodriguez, Christoph Arenz, Maria Montes-Bayón, Michael W Linscheid
Oxidative transformation of cysteine thiol groups into different functional groups is considered a significant posttranslational modification of great importance in pathological and physiological processes. A cysteine sulfenic acid (SA) residue is the transient state for thiol group oxidation and it can react with free thiols to form disulfide bonds or can be further oxidized with reactive oxygen/reactive nitrogen species (ROS/RNS) to form sulfinic and sulfonic acids. The increase in ROS/RNS concentrations is correlated to age-related diseases such as cancer and Alzheimer's disease...
January 17, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28096405/selenium-isotopes-record-extensive-marine-suboxia-during-the-great-oxidation-event
#10
Michael A Kipp, Eva E Stüeken, Andrey Bekker, Roger Buick
It has been proposed that an "oxygen overshoot" occurred during the early Paleoproterozoic Great Oxidation Event (GOE) in association with the extreme positive carbon isotopic excursion known as the Lomagundi Event. Moreover, it has also been suggested that environmental oxygen levels then crashed to very low levels during the subsequent extremely negative Shunga-Francevillian carbon isotopic anomaly. These redox fluctuations could have profoundly influenced the course of eukaryotic evolution, as eukaryotes have several metabolic processes that are obligately aerobic...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28095993/evaluation-of-the-short-term-fate-and-transport-of-chemicals-of-emerging-concern-during-soil-aquifer-treatment-using-select-transformation-products-as-intrinsic-redox-sensitive-tracers
#11
Meriam Muntau, Manoj Schulz, Kevin S Jewell, Nina Hermes, Uwe Hübner, Thomas Ternes, Jörg E Drewes
In this study, known products from oxic transformation of the X-ray contrast medium iopromide were introduced for the first time as intrinsic tracer for in situ characterization of the transition zone between oxic and suboxic conditions during the initial phase of soil-aquifer treatment (SAT). Two wet-dry cycles of a full-scale infiltration basin were monitored to characterize hydraulic retention times, redox conditions, removal of bulk organic parameters and the fate of chemicals of emerging concern (CECs)...
January 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28095880/high-throughput-expression-of-animal-venom-toxins-in-escherichia-coli-to-generate-a-large-library-of-oxidized-disulphide-reticulated-peptides-for-drug-discovery
#12
Jeremy Turchetto, Ana Filipa Sequeira, Laurie Ramond, Fanny Peysson, Joana L A Brás, Natalie J Saez, Yoan Duhoo, Marilyne Blémont, Catarina I P D Guerreiro, Loic Quinton, Edwin De Pauw, Nicolas Gilles, Hervé Darbon, Carlos M G A Fontes, Renaud Vincentelli
BACKGROUND: Animal venoms are complex molecular cocktails containing a wide range of biologically active disulphide-reticulated peptides that target, with high selectivity and efficacy, a variety of membrane receptors. Disulphide-reticulated peptides have evolved to display improved specificity, low immunogenicity and to show much higher resistance to degradation than linear peptides. These properties make venom peptides attractive candidates for drug development. However, recombinant expression of reticulated peptides containing disulphide bonds is challenging, especially when associated with the production of large libraries of bioactive molecules for drug screening...
January 17, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28095695/frontier-molecular-orbital-contributions-to-chlorination-versus-hydroxylation-selectivity-in-the-non-heme-iron-halogenase-syrb2
#13
Martin Srnec, Edward I Solomon
The ability of an Fe(IV)=O intermediate in SyrB2 to perform chlorination vs. hydroxylation was computationally evaluated for different substrates that had been studied experimentally. The π-trajectory for H-atom abstraction (Fe(IV)=O oriented perpendicular to the C-H bond of substrate) was found to lead to the S = 2 five-coordinate HO-Fe(III)-Cl complex with the C• of the substrate, π-oriented relative to both the Cl(-) and OH(-) ligands. From this ferric intermediate, hydroxylation is thermodynamically favored, but chlorination is intrinsically more reactive due to the energy splitting between two key redox-active dπ* frontier molecular orbitals (FMOs)...
January 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28094947/synthesis-of-2-azulenyltetrathiafulvalenes-by-palladium-catalyzed-direct-arylation-of-2-chloroazulenes-with-tetrathiafulvalene-and-their-optical-and-electrochemical-properties
#14
Taku Shoji, Takanori Araki, Shuhei Sugiyama, Akira Ohta, Ryuta Sekiguchi, Shunji Ito, Tetsuo Okujima, Kozo Toyota
Tetrathiafulvalene (TTF) derivatives with 2-azulenyl substituents 5-11 were prepared by the palladium-catalyzed direct cross-coupling reaction of 2-chloroazulenes with TTF in good yield. Photophysical properties of these compounds were investigated by UV-vis spectra and theoretical calculations. Redox behavior of the novel azulene-substituted TTFs was examined by using cyclic voltammetry and differential pulse voltammetry, which revealed their multistep electrochemical oxidation and/or reduction properties...
January 17, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28094922/nano-photoelectrochemical-cell-arrays-with-spatially-isolated-oxidation-and-reduction-channels
#15
Hang-Ah Park, Siyuan Liu, Youngseok Oh, Paul A Salvador, Gregory S Rohrer, Mohammad F Islam
Photoelectrochemical conversion of solar energy is explored for many diverse applications but suffers from poor efficiencies due to limited solar absorption, inadequate charge carrier separation, redox half-reactions occurring in close proximity, and/or long ion diffusion lengths. We have taken a drastically different approach to the design of photoelectrochemical cells (PECs) to spatially isolate reaction sites at the nanoscale to different materials and flow channels, suppressing carrier recombination and back-reaction of intermediates while shortening ion diffusion paths and, importantly, avoiding mixed product generation...
January 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/28094921/uranium-redox-transformations-after-u-vi-coprecipitation-with-magnetite-nanoparticles
#16
Ivan Pidchenko, Kristina O Kvashnina, Tadahiro Yokosawa, Nicolas Finck, Sebastian Bahl, Dieter Schild, Robert Polly, Elke Bohnert, Andre Rossberg, Jörg Göttlicher, Kathy Dardenne, Jörg Rothe, Thorsten Schäfer, Horst Geckeis, Tonya Vitova
Uranium redox states and speciation in magnetite nanoparticles co-precipitated with U(VI) for uranium loadings varying from 1000 to 10000 ppm are investigated by X-ray absorption spectroscopy (XAS). It is demonstrated that the U M4 high energy resolution X-ray absorption near edge structure (HR-XANES) method is capable to clearly characterize U(IV), U(V) and U(VI) existing simultaneously in the same sample. The contributions of the three different uranium redox states are quantified with the iterative transformation factor analysis (ITFA) method...
January 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28094795/impacts-of-chemical-gradients-on-microbial-community-structure
#17
Jianwei Chen, Anna Hanke, Halina E Tegetmeyer, Ines Kattelmann, Ritin Sharma, Emmo Hamann, Theresa Hargesheimer, Beate Kraft, Sabine Lenk, Jeanine S Geelhoed, Robert L Hettich, Marc Strous
Succession of redox processes is sometimes assumed to define a basic microbial community structure for ecosystems with oxygen gradients. In this paradigm, aerobic respiration, denitrification, fermentation and sulfate reduction proceed in a thermodynamically determined order, known as the 'redox tower'. Here, we investigated whether redox sorting of microbial processes explains microbial community structure at low-oxygen concentrations. We subjected a diverse microbial community sampled from a coastal marine sediment to 100 days of tidal cycling in a laboratory chemostat...
January 17, 2017: ISME Journal
https://www.readbyqxmd.com/read/28094788/electronic-control-of-gene-expression-and-cell-behaviour-in-escherichia-coli-through-redox-signalling
#18
Tanya Tschirhart, Eunkyoung Kim, Ryan McKay, Hana Ueda, Hsuan-Chen Wu, Alex Eli Pottash, Amin Zargar, Alejandro Negrete, Joseph Shiloach, Gregory F Payne, William E Bentley
The ability to interconvert information between electronic and ionic modalities has transformed our ability to record and actuate biological function. Synthetic biology offers the potential to expand communication 'bandwidth' by using biomolecules and providing electrochemical access to redox-based cell signals and behaviours. While engineered cells have transmitted molecular information to electronic devices, the potential for bidirectional communication stands largely untapped. Here we present a simple electrogenetic device that uses redox biomolecules to carry electronic information to engineered bacterial cells in order to control transcription from a simple synthetic gene circuit...
January 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28094773/methane-emissions-and-microbial-communities-as-influenced-by-dual-cropping-of-azolla-along-with-early-rice
#19
Jingna Liu, Heshui Xu, Ying Jiang, Kai Zhang, Yuegao Hu, Zhaohai Zeng
Azolla caroliniana Willd. is widely used as a green manure accompanying rice, but its ecological importance remains unclear, except for its ability to fix nitrogen in association with cyanobacteria. To investigate the impacts of Azolla cultivation on methane emissions and environmental variables in paddy fields, we performed this study on the plain of Dongting Lake, China, in 2014. The results showed that the dual cropping of Azolla significantly suppressed the methane emissions from paddies, likely due to the increase in redox potential in the root region and dissolved oxygen concentration at the soil-water interface...
January 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28094525/photocatalytic-color-switching-of-transition-metal-hexacyanometalate-nanoparticles-for-high-performance-light-printable-rewritable-paper
#20
Wenshou Wang, Ji Feng, Yifan Ye, Fenglei Lyu, Yi-Sheng Liu, Jinghua Guo, Yadong Yin
Developing efficient photoreversible color switching systems for constructing rewritable paper is of significant practical interest owing to the potential environmental benefits including forest conservation, pollution reduction, and resource sustainability. Here we report that the color change associated with the redox chemistry of nanoparticles of Prussian blue and its analogues could be integrated with the photocatalytic activity of TiO2 nanoparticles to construct a class of new photoreversible color switching systems, which can be conveniently utilized for fabricating ink-free, light printable rewritable paper with various working colors...
January 17, 2017: Nano Letters
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