Search results for "SOLID-PHASE"
showing 10 items of 178 documents
Active Site Mapping of Xylan-Deconstructing Enzymes with Arabinoxylan Oligosaccharides Produced by Automated Glycan Assembly
2017
Xylan-degrading enzymes are crucial for the deconstruction of hemicellulosic biomass, making the hydrolysis products available for various industrial applications such as the production of biofuel. To determine the substrate specificities of these enzymes, we prepared a collection of complex xylan oligosaccharides by automated glycan assembly. Seven differentially protected building blocks provided the basis for the modular assembly of 2-substituted, 3-substituted, and 2-/3-substituted arabino- and glucuronoxylan oligosaccharides. Elongation of the xylan backbone relied on iterative additions of C4-fluorenylmethoxylcarbonyl (Fmoc) protected xylose building blocks to a linker-functionalized …
Synthetic MUC1 Antitumor Vaccine Candidates with Varied Glycosylation Pattern Bearing R/S-configured Pam3 CysSerLys4.
2016
The Toll-like receptor 2 ligand Pam3 CysSer is of particular interest for the construction synthetic vaccines because of its ability to stimulate of the innate immune system. Such vaccines usually comprise Pam3 CysSer with the natural R-configuration at the glycerol 2-position. Pam3 CysSer peptide vaccines with natural configuration have been shown to be more efficient than the corresponding R/S diastereomers. In order to clarify whether the effect of the configuration of Pam3 Cys on the immune response also applies to glycopeptide vaccines, MUC1 glycopeptide-lipopeptide vaccines bearing either R- or R/S-configured Pam3 CysSerLys4 were compared for their immunological effects. In order to f…
Synthesis of Tn/T Antigen MUC1 Glycopeptide BSA Conjugates and Their Evaluation as Vaccines
2011
The tumor-associated mucin MUC1 over-expressed in most epithelial tumor tissues is considered a promising target for immunotherapy. The extracellular part of MUC1 contains a domain of numerous tandem repeats of the amino acid sequence HGVTSAPDTRPAPGSTAPPA, including five potential O-glycosylation sites. In this study, T9 and S15 have been chosen as the positions of glycosylation. The glycopeptides N-terminally equipped with a triethylene glycol spacer were synthesized by microwave-assisted Fmoc solid-phase peptide synthesis. After detachment from the resin and deprotection, the MUC1 glycopeptides were conjugated to bovine serum albumin (BSA). To evaluate the immunological properties, balb/c…
How Chemical and Sensorial Markers Reflect Gentian Geographic Origin in Chardonnay Wine Macerated with Gentiana lutea Roots?
2020
A Burgundian Chardonnay wine was enriched with Gentiana lutea root powders originating from two French mountain sites (Massif Central and Jura) in order to prepare semi-dry gentian aromatized Chardonnay wine-based drinks. These novel alcoholic beverages were chemically and sensorially characterized for evaluating if the gentian geographic origin influenced bitter and elemental and volatile composition and sensory profiles in the final products. For that, the chemical fingerprint of gentian powders and wines were carried by headspace solid phase microextraction gas chromatography coupled to mass spectrometry (HS&ndash
Analysis of cannabinoids by liquid chromatography–mass spectrometry in milk, liver and hemp seed to ensure food safety
2017
A method for determining cannabinoids, Δ9-tetrahidrocannabinol (THC), 11-nor-9-carboxy-Δ9-THC (THC-COOH) and 11-hidroxy-Δ9-THC (THC-OH) in milk, liver and hemp seeds based on liquid chromatography tandem mass spectrometry has been optimized and validated. Analytes were extracted with methanol and the extracts cleaned-up by solid-phase extraction using Oasis HLB (60 mg). The developed method was validated according to the Commission Decision 2002/657/EC. The decision limit (CCα) and detection capability (CCβ) ranged from 3.10–10.5 ng g−1 and 3.52–11.5 ng g−1, the recoveries were 76–118% and matrix effect ranged from −17.8% to 19.9% in the three matrices studied. The method was applied to foo…
Analysis of furan in coffee of different provenance by head-space solid phase microextraction gas chromatography-mass spectrometry: effect of brewing…
2009
A simple, sensitive and accurate method for the analysis of furan in roasted coffee has been used based on headspace-solid-phase micro-extraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). The extraction was performed using 75-microm carboxen/polydimethylsiloxane fiber. Ionic strength, extraction time and temperature, and desorption time were assessed as the most important parameters affecting the HS-SPME procedure and d(4)-furan was used as the internal standard. The linearity range was in the range 0.0075-0.486 ng g(-1); the LOD and LOQ calculated using the signal-to-noise ratio approach were 0.002 and 0.006 ng g(-1), respectively. The inter- and intra-day precisio…
The Off-Flavor of Pea Flour
2014
Pea products are underused as a protein source in human food because of their “beany” flavor. The objective of the study is to select an extraction method being the most representative for the sensory perception of the beany flavor. Solid phase microextraction (SPME) and purge and trap (P&T) extracts were analyzed by GC-MS and the sensory representation of the extracts was assessed by direct gas chromatography-olfactometry (D-GC-O). Extracted compounds were less numerous in SPME extracts than in P&T extracts. Nevertheless, the SPME method was more suitable because of its good representation of the pea suspension odor.
Understanding fat, proteins and saliva impact on aroma release from flavoured ice-creams
2017
Publication également référencée sous le numéro WOS:000437803400018; The release profile of fourteen aroma compounds was studied in ice cream samples varying in fat and protein, both in level and type. In vitro aroma release was monitored by solid phase micro-extraction gas chromatography using an innovative saliva reactor, which imitated human chewing under temperature control. The results showed that the effect of the fat type on aroma release was smaller than that of fat level. Ice creams with low fat level released more hydrophobic aroma compounds than ice creams with high fat level. At low fat level more aroma compounds were released from ice creams with lower protein content. At high …
Multi‐residue extraction to determine organic pollutants in mussel hemolymph
2021
This study assesses the extraction of eleven pharmaceuticals, five pesticides, five perfluoroalkyl substances, and two illicit drugs in hemolymph from (Mytilus Galloprovincialis). Four extraction procedures using Phree™ Phospholipid Removal cartridges were tested using different volumes of methanol (400 and 600 μL) and acetonitrile (300 and 450 μL). The pollutants were determined by high-performance liquid chromatography–tandem mass spectrometry. The use of methanol gave several problems during the extraction procedure, such as longer times and sample loss. Three methods (acetonitrile 300 and 450 μL; and methanol 600 μL) were validated. Recoveries at three concentration levels (5, 50, and 1…
Natural Product Synthesis on Polymeric Supports—Synthesis and Biological Evaluation of an Indolactam Library
1999
Potent activators of protein kinase C in fibroblasts: This property was determined for several indolactam V analogues (1) with a new cell-based assay system. This tumor-promoting indole alkaloid and analogues thereof can be synthesized efficiently on the solid phase. The key steps of the combinatorial approach are a regioselective amination of the indole ring and an enantioselective enzymatic reaction.