Reactions between 1-Methyl-2-phenyl-3-nitrosoindole, Activated with Benzoyl Chloride, with Indole and Indolizine Derivatives as Nucleophiles: a Case of 1,3-Migration.

2-Phenyl-3-nitrosoindole activated with PhCOCl reacts with indoles and indolizines (NuH) affording products of 1,2-addiction which undergo 1,3-nucleophilic migration in acid media

On the Role of Nitrogen Monoxide (Nitric Oxide) in the Nitration of a Tyrosine Derivative and Model Compounds

The nitration of tyrosine derivatives with nitrogen monoxide (nitric oxide) occurs only in the presence of dioxygen, and the hypothesized mechanism involves nitrogen dioxide (NO2). For better understanding of the reaction mechanism, the nitration of model compounds - such as 1- and 2-naphthols and their corresponding 2- and 1-nitroso derivatives with nitrogen monoxide in the presence and in the absence of dioxygen was studied. The results described here show that tyrosine and naphthols do not undergo nitrosation when they react with (NO)-N-., and so nitrosation of tyrosine in biological systems is highly unlikely. In addition, the oxidation of nitrosonaphthols reversible arrow isonitrosonaphthols by nitric oxide and its derivatives to the corresponding nitro derivatives does not involve the oxoammonium ion, as reported previously. The mechanistic proposals are supported mainly by ESR investigation and electrochemical data

Fluorescence study on rat epithelial cells and liposomes exposed to aromatic nitroxides

This study was performed to evaluate the effects, if any, of aromatic nitroxides, namely, indolinic nitroxides, on membrane fluidity of rat epithelial cells using steady-state fluorescence. These nitroxides are being increasingly considered as new and versatile compounds to reduce oxidative stress in biological systems. Hence, the results obtained in this study will give more insights on the interaction of these compounds with biological structures which at present is lacking, especially in view of their possible application as antioxidant therapeutic agents. The probes DPH and Laurdan which give information on the hydrophobic and hydrophilic-hydrophobic regions of the membrane bilayer, respectively, showed that nitroxide 1 (1,2-dihydro-2-methyl-3H-indole-3-one-1-oxyl) significantly increases membrane fluidity, whereas the corresponding phenylimino nitroxide derivative 2 (1,2-dihydro-2-methyl-3H-indole-3-phenylimino-1-oxyl) leads to membrane rigidification. The aliphatic nitroxide TEMPO included in this study for comparison produced no modifications. Consequently, it appears that the structure of the heterocyclic rings (aromatic or aliphatic) and the substituents may affect membrane fluidity differently. (C) 2004 Elsevier Inc. All rights reserved

A study of gas contaminants and interaction with materials in RPC closed loop systems

Resistive Plate Counters (RPC) detectors at the Large Hadron Collider (LHC) experiments use gas recirculation systems to cope with large gas mixture volumes and costs. In this paper a long-term systematic study about gas purifiers, gas contaminants and detector performance is discussed. The study aims at measuring the lifetime of purifiers with unused and used cartridge material along with contaminants release in the gas system. During the data-taking the response of several RPC double-gap detectors was monitored in order to characterize the correlation between dark currents, filter status and gas contaminants

An analysis of materials used in the RPC detector and in the closed loop gas system of CMS at the LHC.

The results are reported of the study of materials used in the CERN Closed Loop recirculation gas system currently under test with the RPC muon detectors in the CMS experiment at the LHC. Studies include a sampling campaign in a low-radiation environment (cosmic rays at the CERN ISR test site). We describe the dedicated RPC chamber tests, the chemical analysis of the filters and gas used, and discuss the results of the Closed Loop system

Resonance energy transfer sensitises and monitors in situ switching of LOV2-based optogenetic actuators

Engineered light-dependent switches provide uniquely powerful opportunities to investigate and control cell regulatory mechanisms. Existing tools offer high spatiotemporal resolution, reversibility and repeatability. Cellular optogenetics applications remain limited with diffusible targets as the response of the actuator is difficult to independently validate. Blue light levels commonly needed for actuation can be cytotoxic, precluding long-term experiments. We describe a simple approach overcoming these obstacles. Resonance energy transfer can be used to constitutively or dynamically modulate actuation sensitivity. This simultaneously offers on-line monitoring of light-dependent switching and precise quantification of activation-relaxation properties in intact living cells. Applying this approach to different LOV2-based switches reveals that flanking sequences can lead to relaxation times up to 11-fold faster than anticipated. In situ-measured parameter values guide the design of target-inhibiting actuation trains with minimal blue-light exposure, and context-based optimisation can increase sensitivity and experimental throughput a further 10-fold without loss of temporal precision

Loss of ISWI Function in Drosophila Nuclear Bodies Drives Cytoplasmic Redistribution of Drosophila TDP-43

Over the past decade, evidence has identified a link between protein aggregation, RNA biology, and a subset of degenerative diseases. An important feature of these disorders is the cytoplasmic or nuclear aggregation of RNA-binding proteins (RBPs). Redistribution of RBPs, such as the human TAR DNA-binding 43 protein (TDP-43) from the nucleus to cytoplasmic inclusions is a pathological feature of several diseases. Indeed, sporadic and familial forms of amyotrophic lateral sclerosis (ALS) and fronto-temporal lobar degeneration share as hallmarks ubiquitin-positive inclusions. Recently, the wide spectrum of neurodegenerative diseases characterized by RBPs functions' alteration and loss was collectively named proteinopathies. Here, we show that TBPH (TAR DNA-binding protein-43 homolog), the Drosophila ortholog of human TDP-43 TAR DNA-binding protein-43, interacts with the arcRNA hsr omega and with hsr omega-associated hnRNPs. Additionally, we found that the loss of the omega speckles remodeler ISWI (Imitation SWI) changes the TBPH sub-cellular localization to drive a TBPH cytoplasmic accumulation. Our results, hence, identify TBPH as a new component of omega speckles and highlight a role of chromatin remodelers in hnRNPs nuclear compartmentalization

Increased Number of Cerebellar Granule Cells and Astrocytes in the Internal Granule Layer in Sheep Following Prenatal Intra-amniotic Injection of Lipopolysaccharide

Chorioamnionitis is an important problem in perinatology today, leading to brain injury and neurological handicaps. However, there are almost no data available regarding chorioamnionitis and a specific damage of the cerebellum. Therefore, this study aimed at determining if chorioamnionitis causes cerebellar morphological alterations. Chorioamnionitis was induced in sheep by the intra-amniotic injection of lipopolysaccharide (LPS) at a gestational age (GA) of 110 days. At a GA of 140 days, we assessed the mean total and layer-specific volume and the mean total granule cell (GCs) and Purkinje cell (PC) number in the cerebelli of LPS-exposed and control animals using high-precision design-based stereology. Astrogliosis was assessed in the gray and white matter (WM) using a glial fibrillary acidic protein staining combined with gray value image analysis. The present study showed an unchanged volume of the total cerebellum as well as the molecular layer, outer and inner granular cell layers (OGL and IGL, respectively), and WM. Interestingly, compared with controls, the LPS-exposed brains showed a statistically significant increase (+20.4%) in the mean total number of GCs, whereas the number of PCs did not show any difference between the two groups. In addition, LPS-exposed animals showed signs of astrogliosis specifically affecting the IGL. Intra-amniotic injection of LPS causes morphological changes in the cerebellum of fetal sheep still detectable at full-term birth. In this study, changes were restricted to the inner granule layer. These cerebellar changes might correspond to some of the motor or non-motor deficits seen in neonates from compromised pregnancies