Search results for "METHANE"
showing 10 items of 1763 documents
Methylthioacetaldehyde, a possible intermediate metabolite for the production of volatile sulphur compounds from L-methionine by Lactococcus lactis
2004
Volatile sulphur compounds (VSCs) production from L-methionine was studied in Lactococcus lactis. In vitro studies with radiolabelled L-methionine and resting cells of L. lactis revealed that L-methionine was initially converted to alpha-keto-gamma-methylthiobutyrate (KMBA) by a transamination reaction. A part of KMBA was subsequently chemically converted to methylthioacetaldehyde, methanethiol and dimethylsulphides. Chemical conversion of KMBA to methylthioacetaldehyde was dependent on pH, Mn(II) and oxygen. Since methanethiol and dimethylsulphide production was highly related to that of methylthioacetaldehyde, the latter compound was proposed as being an intermediate in VSCs production by…
Targeting the aryl hydrocarbon receptor with a novel set of triarylmethanes
2020
International audience; The aryl hydrocarbon receptor (AhR) is a chemical sensor upregulating the transcription of responsive genes associated with endocrine homeostasis, oxidative balance and diverse metabolic, immunological and inflammatory processes, which have raised the pharmacological interest on its modulation. Herein, a novel set of 32 unsymmetrical triarylmethane (TAM) class of structures has been synthesized, characterized and their AhR transcriptional activity evaluated using a cell-based assay. Eight of the assayed TAM compounds (14, 15, 18, 19, 21, 22, 25, 28) exhibited AhR agonism but none of them showed antagonist effects. TAMs bearing benzotrifluoride, naphthol or heteroarom…
Transcriptional activation of the small GTPase gene rhoB by genotoxic stress is regulated via a CCAAT element
2001
The gene encoding the Ras-related GTPase RhoB-specific is immediate-early inducible by genotoxic treatments. Regulation of transcriptional activation of rhoB is still unclear. Here we show that cells lacking either p53 or c-Fos are not different from wild-type cells with respect to the level of rhoB induction upon UV irradiation, indicating that these transcription factors are not crucial for stimulation of rhoB mRNA expression. Extracts from UV-irradiated and non-irradiated cells revealed similar DNA-binding activities to a 0.17 kb rhoB promoter fragment harboring the functional element(s) necessary for stimulation of rhoB by UV light. By means of immunoprecipitation we found that an ATF-2…
Synthesis, X-ray Structure Determination, and Comprehensive Photochemical Characterization of (Trifluoromethyl)diazirine-Containing TRPML1 Ligands
2021
Potential (trifluoromethyl)diazirine-based TRPML1 ion channel ligands were designed and synthesized, and their structures were determined by single-crystal X-ray diffraction analysis. Photoactivation studies via 19F NMR spectroscopy and HPLC-MS analysis revealed distinct kinetical characteristics in selected solvents and favorable photochemical properties in an aqueous buffer. These photoactivatable TRPML activators represent useful and valuable tools for TRPML photoaffinity labeling combined with mass spectrometry.
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL)-linker in the synthesis of glycopeptide partial structures of complex cell surface glycoproteins.
2003
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL) linker represents a novel fluoride-sensitive anchor for the solid-phase synthesis of protected peptides and glycopeptides. Its cleavage is achieved under almost neutral conditions using tetrabutylammonium fluoride trihydrate in dichloromethane thus allowing the construction of complex molecules sensitive to basic and acidic media commonly required for the cleavage of standard linker systems. The advantages of the PTMSEL linker are demonstrated in the synthesis of glycopeptides from the liver intestine (LI)-cadherin and the mucin MUC1, bearing carbohydrate moieties such as N-linked chitobiose or O-linked sialyl-T(N)-residues. The synthesis of the…
Effect of tin and lead chlorotriphenyl analogues on fruit fly Drosophila hydei and liposomes membrane
2011
This article presents the results of a study investigating the biological activity of triphenyltin chloride (TPhT) and two metalloorganic compounds, triphenyllead chloride (TPhL) and triphenylmethane chloride (TPhC), in their interaction with model membranes and the living organisms of fruit flies Drosophila hydei. The study of model membranes (sonicated liposomes) was conducted using the electron spin resonance (ESR) spin probe technique, whereas the experiment on fruit flies involved investigating their viability on media containing the studied compounds. The test results clearly demonstrate that TPhT affects fruit flies more actively than TPhL (complete lethality after 7 days of culture …
Tris[oligo(1,4-phenylenevinylene)]methylium Dyes
2009
The tris[oligo(1,4-phenylenevinylene)]carbinols 2a–f (n =1–4) and the tris(4-styrylphenyl)methanes 7a,b have been prepared by Wittig–Horner (3 + 4a–f 2a–f) and Siegristreactions (5 + 6a,b 7a,b). The Wittig–Horner reactions in these examples are accompanied by an autoxidation, whereas a reduction occurs in the Siegrist reactions. Compound 2a, the lowest member (n = 1) of the series 2a–d with terminal dialkylamino groups, generates first, on treatment with acids, the methylium dye 2′a, which absorbs far into the NIR region (λmax = 1100 nm). The higher members 2b,c (n = 2,3) of the carbinol series yield by acidic treatment only N-protonated methylium dyes 2″′b,c. The different behavior is due …
Global sensitivity of aviation NO<sub>x</sub> effects to the HNO<sub>3</sub>-forming channel …
2013
Abstract. The impact of a recently proposed HNO3-forming channel of the HO2 + NO reaction on atmospheric ozone, methane and their precursors is assessed with the aim to investigate its effects on aviation NOx induced radiative forcing. The first part of the study addresses the differences in stratospheric and tropospheric HOx-NOx chemistry in general, by comparing a global climate simulation without the above reaction to two simulations with different rate coefficient parameterizations for HO2 + NO → HNO3. A possible enhancement of the reaction by humidity, as found by a laboratory study, particularly reduces the oxidation capacity of the atmosphere, increasing methane lifetime significantl…
The European Union's Methane Strategy
2023
This document has been included as a part of the teaching materials funded by the UNESCO Chair of the University of Valencia, 2023. This paper dicusses about the European Union's Methane Strategy
Liquid–Liquid Equilibria of Water + Ethanol + 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide Ternary System: Measurements and Correla…
2015
In this work authors present the experimental liquid–liquid equilibria (LLE) data of water + ethanol + 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([bmim][Tf2N]) system at different temperatures. The LLE of the system was obtained in the temperature range from 283.2 to 323.2 K. The nonrandom two liquid (NRTL) and universal quasichemical (UNIQUAC) models were used to correlate ternary systems. The equilibrium compositions were successfully correlated by the interaction parameters from both models, however UNIQUAC gave a more accurate correlation. Finally, a study about the solvent capability of ionic liquid was made in order to evaluate the possibility of separating the mi…