Aurélie Fildier

Hyperbranched cyclic and multicyclic poly(etherketone)s by polycondensation of isosorbide and isomannide with 2,6,4′-trifluorobenzophenone and 1,3,5-tris(4-fluorobenzoyl) benzene

1,3,5-Tris(4-fluorobenzoyl)benzene (TFBB) and 2,6,4′-trifluorobenzophenone (TFB) were polycondensed with isosorbide and isomanide. All polycondensations were performed in a mixture of dimethyl sulfoxide and toluene with potassium carbonate as promotor. Optimal concentration to avoid gelation was set at 0.06 mol L−1. The different cyclization tendencies on the basis of monomers conformations are discussed. In the TFB series, the feed ratio isosorbide/TFB was varied from 1.0:1.0 to 1.5:1.0. A majority of linear and hyperbranched species were identified as main reaction products by matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry regardless of the diol with slight cyclization tendency for isomannide. When TFBB was polycondensed with isosorbide, the cyclization tendency was significantly improved. The products obtained at a feed ratio of 1.41/1.0 and 1.51/1.0 were rich in cyclic and multicyclic species. More interesting results were obtained from the polycondensation of TFBB and isomannide, giving rise majoritarily to cyclic, bicyclic, and multicyclic species. Differential scanning calorimetric measurements indicated high glass transition temperature (around 200°C).

Phytochemical and Biological Investigation of Two Diplotaxis Species Growing in Tunisia: D. virgata & D. erucoides

A phytochemical investigation of Diplotaxis virgata D.C. and D. erucoides (L.) D.C. (Brassicaceae) offered to the isolation of two new flavonoids isorhamnetin-3-O-α-l-glucopyranoside (1) and rhamnetin-3,3ʹ-di-O-β-d-glucopyranoside (2), respectively. Their structures have been elucidated from the extended spectroscopic methods, including 1D- and 2D-NMR, UV and mass spectrometry analysis and by comparison with literature data. The fatty acid composition of the hexane extracts of the two species was also investigated by using GC-MS. The antioxidant activity of ethanol, ethyl acetate, n-butanol extracts and the isolated compounds from the two species was evaluated using DPPH and ABTS+ scavenging assays. All the tested samples showed an efficient radical scavenging ability, with IC50 values ranging from 16–40 µg/mL for the DPPH and from 17–44 µg/mL for the ABTS+ assays. In addition, the antibacterial activity of the prepared extracts and compounds 1 and 2, determined by well diffusion agar method against two Gram positive and five Gram negative bacteria, was evaluated and the results showed significant effects against all strains used.

Synthesis and characterization of isosorbide-based α,ω-dihydroxyethersulfone oligomers

Functionalization of bio-based oligomers is a relevant approach in order to allow these materials to replace more conventional and nonbiodegradable polymers in a wider range of applications. This article will report on the hydroxylation of isosorbide-based ethersulfone oligomers. The hydroxy end-group was controlled by the variation of polycondensation parameters. Comparative study was conducted to assess the effect of isosorbide excess and the monomer concentration on structural composition and molecular weights of produced oligomers. Depending on reaction conditions, various products were synthesized, mainly α,ω-dihydroxyethersulfone oligomers. The characterization of the synthesized polyethersulfone was demonstrated by MALDI–TOF, NMR spectroscopy, differential scanning calorimetry, and size exclusion chromatography.

A complementary LC-ESI-MS and MALDI-TOF approach for screening antibacterial proteomic signature of farmed European sea bass mucus.

Antibacterial protection in the mucus is provided by antimicrobial compounds and till now few numbers of AMP and proteins were identified. Herein, mass spectral profiling of fresh mucus from farmed sea bass (Dicentrarchus labrax) using Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometer (MALDI-TOF) and liquid chromatography mass spectrometry is investigated in order to survey the infective/healthy status of the mucus. We identify AMP peptides of 2891.7, 2919.45 and 2286.6 Da molecular weight respectively and characterize Chrysophsins in the mucus of Dicentrarchus labrax. These peptides display broad-spectrum bactericidal activity against Gram-negative (Minimum Inhibitory Concentrations namely MICs < 0.5 μM) and Gram-positive bacteria (MICs < 0.5 μM) including Escherichia coli and Bacillus subtilis. Furthermore, sensitivity to yeast Candida albicans is reported for the first time and shows interesting MICs of less than 2 μM. We also demonstrate that the fish pathogen Aeromonas salmonoicida is sensitive to Chrysophsins (MICs ranging between 5 and 14 μM). Our mucus molecular mass mapping developed approach allows for fast exploration of immune status. Our data provides evidence that Chrysophsins are secreted by immune cells and are released in mucus of non-challenged farmed European sea bass. These results suggest that Chrysophsins, secreted by gills of red sea bream, are an important widespread component of Teleostei defense against disease.

High-Resolution Mass Spectrometry as a Tool To Evaluate the Sample Preparation of Sludge

This study explored the sample preparation steps based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) of a complex matrix, such as sewage sludge, regarding their impacts on the chemical signatures of the samples obtained via high-resolution mass spectrometry (HRMS). The effects on the HRMS signal of the intrinsic parameters of the QuEChERS method, such as the extraction solvent, the buffer salt, or the purification procedure, have been evaluated. Different strategies have been used to perform these evaluations, such as a comparison of the total number of HRMS signals, a comparison of the targeted screening based on more than 100 compounds, and a comparison of a nontargeted screening based both on the study of the most discriminating couples [mass-to-charge ratio (m/z); retention time (tR)] and on the most intense peaks. Moreover, two specific methods dedicated to the extraction of surfactants and drugs have been added to this comparison to visualize the impact of specific conditions on the chemical signature. This study provides the first information on the impact of sample preparation on the HRMS analysis of sludge. It shows that acetonitrile is the most effective solvent for obtaining maximum information from sewage sludge. The comparison of the different cleanup procedures emphasizes the significance of this step and demonstrates the connection between the intrinsic physicochemical properties of molecules and the operating conditions of the extraction, particularly the pH. Moreover, the study highlights that surfactants, i.e., quaternary ammoniums in the positive ionization mode and linear alkylbenzene sulfonates in the negative mode, are the most discriminating compounds.