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701.
Electrochemical Monitoring of the Early Events of Hydrogen Peroxide Production by Mitochondria 下载免费PDF全文
Dr. Emmanuel Suraniti Salem Ben‐Amor Pauline Landry Prof. Michel Rigoulet Prof. Eric Fontaine Prof. Serge Bottari Dr. Anne Devin Prof. Neso Sojic Dr. Nicolas Mano Dr. Stéphane Arbault 《Angewandte Chemie (International ed. in English)》2014,53(26):6655-6658
Mitochondria consume oxygen in the respiratory chain and convert redox energy into ATP. As a side process, they produce reactive oxygen species (ROS), whose physiological activities are still not understood. However, current analytical methods cannot be used to monitor mitochondrial ROS quantitatively and unambiguously. We have developed electrochemical biosensors based on peroxidase‐redox polymer‐modified electrodes, providing selective detection of H2O2 with nanomolar sensitivity, linear response over five concentration decades, and fast response time. The release of H2O2 by mitochondria was then monitored under phosphorylating or inhibited respiration conditions. We report the detection of two concomitant regimes of H2O2 release: large fluxes (hundreds of nM ) under complex III inhibition, and bursts of a few nM immediately following mitochondria activation. These unprecedented bursts of H2O2 are assigned to the role of mitochondria as the hub of redox signaling in cells. 相似文献
702.
Muller F Fontaine P Remita S Fauré MC Lacaze E Goldmann M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(12):4791-4794
An application of the radiolysis method using an X-ray synchrotron beam is developed as a novel approach to the synthesis of metal-organic films with controlled shapes and thickness. We demonstrate that a Langmuir monolayer deposited onto a silver ion containing subphase, irradiated by an incident beam impinging below the critical angle for total reflection, induces the synthesis of a stable nanostructured silver-organic ultrathin film at the air-water interface. The X-ray scattering is also used to monitor in situ the structure of the silver layer during the synthesis process. The layer is observed by atomic force microscopy after its transfer onto a silicon substrate. One observes a film thickness of 4.6 nm, in good agreement with the X-ray penetration depth, about 4.5 nm. The silver structure is oriented by the initial organic film phase. This experiment demonstrates the considerable potential of this approach to produce various controlled metal-organic films with a surfactant self-assembly as a template. 相似文献
703.
Michiko Atsumi Leticia Gonzlez Chantal Daniel 《Journal of photochemistry and photobiology. A, Chemistry》2007,190(2-3):310-320
The absorption spectroscopy of [Ru(phen)2dppz]2+ and [Ru(tap)2dppz]2+ (phen = 1,10-phenanthroline, tap = 1,4,5,8-tetraazaphenanthrene; dppz = dipyridophenazine) complexes used as molecular light switches by intercalation in DNA has been analysed by means of Time-Dependent Density Functional Theory (TD-DFT). The electronic ground state structures have been optimized at the DFT (B3LYP) level of theory. The absorption spectra are characterized by a high density of excited states between 500 nm and 250 nm. The absorption spectroscopy of [Ru (phen)2dppz]2+ in vacuum is characterized by metal-to-ligand-charge-transfer (MLCT) transitions corresponding to charge transfer from Ru(II) either to the phen ligands or to the dppz ligand with a strong MLCT () absorption at 411 nm. In contrast, the main feature of the lowest part of the vacuum theoretical spectrum of [Ru(tap)2dppz]2+ between 522 nm and 400 nm is the presence of various excited states such as MLCT (), ligand-to-ligand-charge-transfer LLCT () or intra-ligand IL () states. When taking into account solvent corrections within the polarizable continuum model (PCM) approach (H2O, CH3CN) the absorption spectrum of [Ru(tap)2dppz]2+ is dominated by a strong absorption at 388 nm (CH3CN) or 390 nm (H2O) assigned to a 1IL () corresponding to a charge transfer from the outside end of the dppz ligand to the site of coordination to Ru(II). These differences in the absorption spectra of the two Ru(II) complexes have dramatic effects on the mechanism of deactivation of these molecules after irradiation at about 400 nm. In particular, the electronic deficiency at the outside end of the dppz ligand created by absorption to the 1IL state will favour electron transfer from the guanine to the Ru(II) complex when it is intercalated in DNA. 相似文献
704.
Arafat Tayeb Aur��lie Labbe Alexandre Bureau Chantal M��rette 《Computational Statistics》2011,26(3):539-560
The study of genetic properties of a disease requires the collection of information concerning the subjects in a set of pedigrees. The main focus of this study was the detection of susceptible genes. However, even with large pedigrees, the heterogeneity of phenotypes in complex diseases such as Schizophrenia, Bipolar and Autism, makes the detection of susceptible genes difficult to accomplish. This is mainly due to a genetic heterogeneity: many genes phenomena are involved in the disease. In order to reduce this heterogeneity, our idea consists in sub-typing the disease and in partitioning the population into more alike sub-groups. We developed a probabilistic model based on a Latent Class Analysis (LCA) that takes into account the familial dependence inside a pedigree, even for large pedigrees. It also takes into account individuals with missing and partially missing measurements. Estimation of model parameters is performed by an EM algorithm, and computations for the E step inside a pedigree are achieved using a pedigree peeling algorithm. When more than one model are fitted, we use model selection strategies such as cross-validation or/and BIC approaches to choose the suitable model among a set of candidates. Moreover, we present a simulation based on a genetic disease class model and we show that our model leads to better individual classification than the model that assumes independence among subjects. An application of our model to a Schizophrenia-Bipolar pedigree data set from Eastern Quebec is also performed. 相似文献
705.
Verena I. Böhmer Prof. Wiktor Szymanski Keimpe-Oeds van den Berg Chantal Mulder Piermichele Kobauri Hugo Helbert Dr. Dion van der Born Friederike Reeβing Anja Huizing Dr. Marten Klopstra Douwe F. Samplonius Dr. Ines F. Antunes Jürgen W. A. Sijbesma Dr. Gert Luurtsema Prof. Wijnand Helfrich Dr. Ton J. Visser Prof. Ben L. Feringa Prof. Philip H. Elsinga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(47):10871-10881
Since the seminal contribution of Rolf Huisgen to develop the [3+2] cycloaddition of 1,3-dipolar compounds, its azide–alkyne variant has established itself as the key step in numerous organic syntheses and bioorthogonal processes in materials science and chemical biology. In the present study, the copper(I)-catalyzed azide–alkyne cycloaddition was applied for the development of a modular molecular platform for medical imaging of the prostate-specific membrane antigen (PSMA), using positron emission tomography. This process is shown from molecular design, through synthesis automation and in vitro studies, all the way to pre-clinical in vivo evaluation of fluorine-18- labeled PSMA-targeting ‘F-PSMA-MIC’ radiotracers (t1/2=109.7 min). Pre-clinical data indicate that the modular PSMA-scaffold has similar binding affinity and imaging properties to the clinically used [68Ga]PSMA-11. Furthermore, we demonstrated that targeting the arene-binding in PSMA, facilitated through the [3+2]cycloaddition, can improve binding affinity, which was rationalized by molecular modeling. The here presented PSMA-binding scaffold potentially facilitates easy coupling to other medical imaging moieties, enabling future developments of new modular imaging agents. 相似文献