Search results for "acids"
showing 10 items of 3520 documents
Lipid dependence of diadinoxanthin solubilization and de-epoxidation in artificial membrane systems resembling the lipid composition of the natural t…
2006
In the present study, the solubility and enzymatic de-epoxidation of diadinoxanthin (Ddx) was investigated in three different artificial membrane systems: (1) Unilamellar liposomes composed of different concentrations of the bilayer forming lipid phosphatidylcholine (PC) and the inverted hexagonal phase (H(II) phase) forming lipid monogalactosyldiacylglycerol (MGDG), (2) liposomes composed of PC and the H(II) phase forming lipid phosphatidylethanolamine (PE), and (3) an artificial membrane system composed of digalactosyldiacylglycerol (DGDG) and MGDG, which resembles the lipid composition of the natural thylakoid membrane. Our results show that Ddx de-epoxidation strongly depends on the con…
Unsaturated fatty acids from food and in the growth medium improve growth of Bacillus cereus under cold and anaerobic conditions.
2013
International audience; In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containing fraction of spinach, but not the hydrophilic fraction, restored growth of B. cereus under cold and anaerobiosis when added to the chemically defined medium. This fraction was rich in unsaturated, low melting point fatty acids. Addition of phosphatidylcholine containing unsaturated, low melting point, fatty acids similarly…
Role of Membrane Lipids for the Activity of Pore Forming Peptides and Proteins
2010
Bilayer lipids, far from being passive elements, have multiple roles in polypeptide-dependent pore formation. Lipids participate at all stages of the formation of pores by providing the binding site for proteins and peptides, conditioning their active structure and modulating the molecular reorganization of the membrane complex. Such general functions of lipids superimpose to other particular roles, from electrostatic and curvature effects to more specific actions in cases like cholesterol, sphingolipids or cardiolipin.
Two Years at Meridiani Planum: Results from the Opportunity Rover
2006
The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling ∼8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict “hopper crystals” that might reflect the formation of halite, thick weathering rinds on rock surfaces, resistant fracture fills, and networks of polygonal fractures likely caused by dehydration of sulfate salts. Chemical variations with depth show that the siliciclastic fraction of outcrop rock has undergon…
Adducts of free-base meso-tetraarylporphyrins with trihaloacetic acids: Structure and photostability
2020
Abstract Four diverse meso-tetraarylporphyrins in the form of diprotonated adducts with trifluoro-, trichloro-, tribromoacetic acids and acetic acid were investigated in benzene solution. Despite similar structural distortion of the chromophore system due to protonation, the respective adducts demonstrated different photostability when exposed to UV irradiation. The trifluoro- and trichloroacetic adducts, and the acetic acid one, showed some common features both molecular and in the mechanism of photodegradation. However, the tribromo-derivative decayed according to a different kinetic scheme, revealing a considerable impact of the bromine atoms upon the pyrrole units of the porphyrin macro…
Plasmatic extracellular vesicle microRNAs in malignant pleural mesothelioma and asbestos-exposed subjects suggest a 2-miRNA signature as potential bi…
2017
Background Malignant Pleural Mesothelioma (MPM) is an aggressive cancer mainly caused by asbestos exposure and refractory to current therapies. Specific diagnostic markers for early MPM diagnosis are needed. Changes in miRNA expression have been implicated in several diseases and cancers, including MPM. We examined if a specific miRNA signature in plasmatic extracellular vesicles (EV) may help to discriminate between malignant pleural mesothelioma patients (MPM) and subjects with Past Asbestos Exposure (PAE). Methodology/Principal findings We investigated 23 MPM patients and 19 cancer-free subjects with past asbestos exposure (PAE). We screened 754 miRNAs in plasmatic EVs by OpenArray and f…
The soluble loop BC region guides, but not dictates, the assembly of the transmembrane cytochrome b6
2017
Studying folding and assembly of naturally occurring α-helical transmembrane proteins can inspire the design of membrane proteins with defined functions. Thus far, most studies have focused on the role of membrane-integrated protein regions. However, to fully understand folding pathways and stabilization of α–helical membrane proteins, it is vital to also include the role of soluble loops. We have analyzed the impact of interhelical loops on folding, assembly and stability of the heme-containing four-helix bundle transmembrane protein cytochrome b6 that is involved in charge transfer across biomembranes. Cytochrome b6 consists of two transmembrane helical hairpins that sandwich two heme mol…
Isoprenoid biosynthesis in eukaryotic phototrophs: a spotlight on algae.
2011
Isoprenoids are one of the largest groups of natural compounds and have a variety of important functions in the primary metabolism of land plants and algae. In recent years, our understanding of the numerous facets of isoprenoid metabolism in land plants has been rapidly increasing, while knowledge on the metabolic network of isoprenoids in algae still lags behind. Here, current views on the biochemistry and genetics of the core isoprenoid metabolism in land plants and in the major algal phyla are compared and some of the most pressing open questions are highlighted. Based on the different evolutionary histories of the various groups of eukaryotic phototrophs, we discuss the distribution an…
Metabolism of n-Butyl Benzyl Phthalate in the Female Wistar Rat. Identification of New Metabolites
1999
International audience; n-Butyl benzyl phthalate (BBP), a plasticizer used in polyvinylchloride (PVC) and other polymers, has been orally administered to female Wistar rats with four doses (150, 475, 780 and 1500 mg/kg body weight/day) for 3 consecutive days. Metabolites recovered in urines were analysed by gas chromatography±mass spectrometry (GC±MS) after 24, 48 and 72 hours. Six metabolites were identi®ed. Mono-n-butyl phthalate (MBuP) and mono-n-benzyl phthalate (MBeP) represented respectively 29± 34% and 7±12 % of the total recovered metabolites. Hippuric acid, the main metabolite of benzoic acid, represented the second major metabolite (51±56%). Phthalic acid, benzoic acid and an o-ox…
Walnut Consumption, Plasma Metabolomics, and Risk of Type 2 Diabetes and Cardiovascular Disease
2021
BACKGROUND: Walnut consumption is associated with lower risk of type 2 diabetes (T2D) and cardiovascular disease (CVD). However, it is unknown whether plasma metabolites related to walnut consumption are also associated with lower risk of cardiometabolic diseases. OBJECTIVES: The study aimed to identify plasma metabolites associated with walnut consumption and evaluate the prospective associations between the identified profile and risk of T2D and CVD. METHODS: The discovery population included 1833 participants at high cardiovascular risk from the PREvención con DIeta MEDiterránea (PREDIMED) study with available metabolomics data at baseline. The study population included 57% women (baseli…