Synthèse d une nouvelle série de thiosucres et sulfoniums insaturés à partir de dithioacétals de cétène dérivés de sucres

REIMS-BU Sciences (514542101) / SudocSudocFranceF

Study of the conformational behaviour of trehalose mycolates by FT-IR spectroscopy

Mycolic acids are fundamental cell wall components, found in the outer membrane barrier (mycomembrane) of Mycobacterium related genera, that have shown antigenic, murine innate immunity inducting and inflammatory activity triggering action. The mycolic acid derivatives, such as the lipid extractable trehalose monomycolates (TMM) and dimycolates (TDM), have been extensively investigated by several biochemical and biological methods and, more recently, we have performed the first neutron scattering measurements on these molecules in order to characterize their dynamical behavior as well as their rigidity properties. In the present paper, we show the first systematic FT-IR study on TMM, TDM and glucose monomycolate (GMM). It includes the analysis of individual lipids but also mixtures of TMM/TDM (ratio of 1:1) or TMM/GMM (ratio of 1:2). The present work is aimed to the first characterization of the vibrational behavior of mycolates and their mixtures enabling us to elucidate the molecular mechanisms responsible for the capability of mycolic acids to affect the flexibility and permeability properties of the mycomembrane. As a whole, the present FT-IR findings provide information that have relevant biological implications, allowing to demonstrate that the membrane fluidity is not only linked to the chain length, but also to the specific conformational behavior adopted by mycolates, which in the mixtures is strongly affected by their mutual interactions. In addition, the capability of trehalose to drive the mycolate conformational behavior and then the chain order and packing is emphasized; due to the TDM relevant evidences shown by our data, this trehalose effect could be related to the TDM toxicity and inflammation action

Synthesis of D- and L-erythro 1,5-dithiopent-1-enopyranoside sulfonium salts and their evaluation as glycosidase inhibitors

A series of sulfonium salts derived from 1,5-dithiopent-1-enopyranosides was prepared in a three-step sequence from protected D- and L-erythrofuranoses. The key step is the nucleophilic displacement of a leaving group by a sulfur atom of carbohydrate-derived ketene dithioacetals. Such compounds were assayed for their properties as glycosidase inhibitors. (C) 2009 Elsevier Ltd. All rights reserved

Irreversible inhibition of IspG, a target for the development of new antimicrobials, by a 2‐vinyl analogue of its MEcPP substrate

International audienc

First access to a mycolic acid-based bioorthogonal reporter for the study of the mycomembrane and mycoloyltransferases in Corynebacteria

In this study, we report the first synthesis of an alkyne-based trehalose monomycolate probe containing a β-hydroxylated fatty acid and an α-branched chain similar to those of the natural mycolic acid. We demonstrate its utility for the labeling of the mycomembrane of Corynebacteria as well as for the study of mycoloyltransferases

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

This paper reports an efficient preparation of bridged bis-β-CD AZO-CDim 1 bearing azobenzene as a linker and exhibiting high solubility in water. The photoisomerization properties were studied by UV–vis and HPLC and supported by ab initio calculations. The cis/trans ratio of AZO-CDim 1 is 7:93 without irradiation and 37:63 after 120 min of irradiation at 365 nm; the reaction is reversible after irradiation at 254 nm. The photoinduced, switchable binding behavior of AZO-CDim 1 was evaluated by ITC, NMR and molecular modeling in the presence of a ditopic adamantyl guest. The results indicate that AZO-CDim 1 can form two different inclusion complexes with an adamantyl dimer depending on its photoinduced isomers. Both cavities of cis-AZO-CDim 1 are complexed simultaneously by two adamantyl units of the guest forming a 1:1 complex while trans-AZO-CDim 1 seems to lead to the formation of supramolecular polymers with an n:n stoichiometry

The Evolution of the Seine Basin Water Bodies Through Historical Maps

International audienc