The B23 Circular Dichroism beamline at Diamond Light Source has been operational since 2009 and has seen visits from more than 200 user groups, who have generated large amounts of data. Based on the experience of overseeing the users' progress at B23, four key areas requiring the most assistance are identified: planning of experiments and note-keeping; designing titration experiments; processing and analysis of the collected data; and production of experimental reports. To streamline these processes an integrated software package has been developed and made available for the users. The subsequent article summarizes the main features of the software.
Cyclic B-type proanthocyanidins in red wines and grapes have been discovered recently. However, proanthocyanidins of a different chemical structure (non-cyclic A-type proanthocyanidins) already known to be present in cranberries and wine possess an identical theoretical mass. As a matter of fact, the retention times and the MS/MS fragmentations found for the proposed novel cyclic B-type tetrameric proanthocyanidin in red wine and the known tetrameric proanthocyanidin in a cranberry extract are herein shown to be identical. Thus, hydrogen/deuterium (H/D) exchange was applied to HPLC-HRMS/MS to confirm the actual chemical structure of the new oligomeric proanthocyanidins. The comparison of the results in water and deuterium oxide and between wine and cranberry extract indicates that the cyclic B-type tetrameric proanthocyanidin is the actual constituent of the recently proposed novel tetrameric species ([CHO], m/z 1153.2608). Surprisingly, the same compound was also identified as the main tetrameric proanthocyanidin in cranberries. Finally, a totally new cyclic B-type hexameric proanthocyanidin ([CHO], m/z 1729.3876) belonging to this novel class was identified for the first time in red wine. Graphical Abstract ᅟ.
The antioxidant properties of fresh black truffles (Tuber melanosporum)melanosporum) (T.) refrigerated at 4 °C 4 °C under different packaging conditions: air atmosphere (A), (A), reduced pressure (V), (V), mix 1% O 2 /99% N 2 (ON) and mix 40% CO 2 /60% N 2 (CN) were evaluated during 28 d 28 days of storage. The results were compared with the volatile fingerprint determined by SPME-GC/MS and with the phenolic antioxidants characterized by HPLC-MS/MS. HPLC-MS/MS. The total antioxidant content and the antioxidant activity decreased during the storage, regardless of the packaging method. The principal components component analysis (PCA) showed that the total antioxidant content was well correlated with low storage times, high antioxidant activity and three volatile aldehydes. In contrast, 2-propyl-butanoate and 2-nonen-1-ol inversely correlated with the antioxidant activity, as well as gentisic acid, which was the only phenolic antioxidant which increased during the storage. V, CN and ON were always better strategies than A to preserve the freshness of T. T. However, V is a valid and cheap alternative to normal atmosphere to prolong the shelf life for up to two weeks.
A-type resistance towards “last-line” glycopeptide antibiotic vancomycin in the leading hospital acquired infectious agent, the enterococci, is the most common in the UK. Resistance is regulated by the VanRASA two-component system, comprising the histidine sensor kinase VanSA and the partner response regulator VanRA. The nature of the activating ligand for VanSA has not been identified, therefore this work sought to identify and characterise ligand(s) for VanSA. In vitro approaches were used to screen the structural and activity effects of a range of potential ligands with purified VanSA protein. Of the screened ligands (glycopeptide antibiotics vancomycin and teicoplanin, and peptidoglycan components N-acetylmuramic acid, D-Ala-D-Ala and Ala-D-y-Glu-Lys-D-Ala-D-Ala) only glycopeptide antibiotics vancomycin and teicoplanin were found to bind VanSA with different affinities (vancomycin 70 μM; teicoplanin 30 and 170 μM), and were proposed to bind via exposed aromatic residues tryptophan and tyrosine. Furthermore, binding of the antibiotics induced quicker, longer-lived phosphorylation states for VanSA, proposing them as activators of type A vancomycin resistance in the enterococci.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.