37 research outputs found
Synthesis of 2‐Substituted Cyclobutanones by a Suzuki Reaction and Dephosphorylation Sequence
Would it still be possible to identify irradiated lipid-containing foods towards the end of their shelf-life?
The current British and European Standard (BS EN1785: 2003) for the identification of gamma irradiated foods is based on the isolation and detection of a group of lipid derived 2-alkylcyclobutanone compounds that are formed following irradiation. The 2-alkylcyclobutanones (2-dodecylcyclobutanone {DCB}, and 2-tetradecylcyclobutanone {TCB}) have been validated as radiolytic markers in the routine chemical identification of irradiated foods. This study was carried out with the view to answering a key question in relation to the fate of irradiated foods post irradiation and during storage; would it still be possible to correctly identify foods as having being irradiated towards the end of their shelf-life? Chemical detection method was employed to closely follow and plot the loss of each of these radiolytic markers throughout shelf-life. Significant levels of DCB and TCB were detected in all irradiated beef samples, which have been stored over 12-month period. Despite the considerable drop in the levels of both markers with time, it was still possible to detect both markers and therefore confirm that the stored samples had in fact been previously irradiated. These reported findings confer additional traceability choice to the global market of irradiated foods that may consequently, raise confidences among concerned parties
Scope and Applicability of an Expedient Synthesis Leading to Polysubstituted 3‐(Carboxyphenyl)pyrroles
The antibacterial prodrug activator Rv2466c is a mycothiol-dependent reductase in the oxidative stress response of Mycobacterium tuberculosis
The Mycobacterium tuberculosis rv2466c gene encodes an oxidoreductase enzyme annotated as DsbA. It has a CPWC active-site motif embedded within its thioredoxin fold domain and mediates the activation of the prodrug TP053, a thienopyrimidine derivative that kills both replicating and nonreplicat-ing bacilli. However, its mode of action and actual enzymatic function in M. tuberculosis have remained enigmatic. In this study, we report that Rv2466c is essential for bacterial survival under H2O2 stress. Further, we discovered that Rv2466c lacks oxidase activity; rather, it receives electrons through the mycothiol/mycothione reductase/NADPH pathway to activate TP053, preferentially via a dithiol– disulfide mechanism. We also found that Rv2466c uses a monothiol– disulfide exchange mechanism to reduce S-mycothiolated mixed disulfides and intramolecular disulfides. Genetic, phylogenetic, bioinformat-ics, structural, and biochemical analyses revealed that Rv2466c is a novel mycothiol-dependent reductase, which represents a mycoredoxin cluster of enzymes within the DsbA family different from the glutaredoxin cluster to which mycoredoxin-
Gold-Catalyzed Tandem Cyclizations of 1,6-Diynes Triggered by Internal N- and O-Nucleophiles
One-Pot Synthesis of Indole-Fused Scaffolds via Gold-Catalyzed Tandem Annulation Reactions of 1,2-Bis(alkynyl)-2-en-1-ones with Indoles
Gap analysis of the Ramsar site network at 50: over 150 important Mediterranean sites for wintering waterbirds omitted
The Mediterranean Basin is a biodiversity hotspot. Wetlands make a key contribution to this status, but many of them remain outside the Ramsar network fifty years after the establishment of the Ramsar Convention. Here we evaluate the extent to which the Mediterranean Ramsar network covers wetlands of international importance for wintering waterbirds using the Ramsar Convention criteria 2 (species of conservation concern), 5 (> 20,000 waterbirds) and 6 (1% of a population). These criteria were applied to 4186 sites in 24 Mediterranean countries using counts of 145 wintering waterbird species from 1991 to 2017. We identified 161 sites of international importance for waterbirds that have not yet been declared as Ramsar sites, which could be added to the 180 current Mediterranean Ramsar sites established based on waterbird criteria (criteria 5 and/or 6). Among these sites, a subset of 32 very important sites reached double the required level for at least one criterion and 95 were not protected by any site conservation status. Coastal wetlands represented half of the Ramsar gap for waterbirds. We identified that an additional 1218 monitored sites could be provisionally considered as internationally important and thus require more survey efforts to assess their status. This study highlights a lack of participation of the Mediterranean countries to build the Ramsar network for wetland protection. Our results should help policymakers and managers to prioritize future Ramsar site designation, notably in the Middle East and Western European region where important gaps were identified