Hardware and Software for Embedded Compact: Broadband Low Field NMR spectrometers (ECBLFNMR)

Numerous compact NMR spectrometers have been designed for an easy measurement of proton NMR spectra. High sensitivity and resolution can be reached even with low field spectrometers (LFNMR) (i.e. 60 MHz), thanks to great improvements in electronic hardware, which open up a wide field of analytical quantification and relaxation applications. A specificity of Low field NMR spectrometer is the use of a permanent and cryogen free magnet technology, avoiding the need for weekly and expensive cryogenic services. Here we present and describe a low field NMR spectrometer fabricated in our laboratory. This spectrometer (ECBLFNMR) operates at basic resonant frequencies ranging from 1 to 60 MHz, with standard sample diameter (5-10 mm). All the embedded hardware is very compact and requires only a 24 V DC power supply, so this spectrometer is portable, easy to install and has a small footprint. This ECBFLNMR is dedicated to education and quantification, and enables low-field NMR research. It may be coupled with scientific experiments not requiring high magnetic fields

Discovery of pyrido[3,4-g]quinazoline derivatives as CMGC family protein kinase inhibitors: Design, synthesis, inhibitory potency and X-ray co–crystal structure

The design and synthesis of new pyrido[3,4-g]quinazoline derivatives is described as well as their protein kinase inhibitory potencies toward five CMGC family members (CDK5, CK1, GSK3, CLK1 and DYRK1A). The interest for this original tricyclic heteroaromatic scaffold as modulators of CLK1/DYRK1A activity was validated by nanomolar potencies (compounds 12 and 13). CLK1 co-crystal structures with two inhibitors revealed the binding mode of these compounds within the ATP-binding pocket

Cloud Microorganisms, an Interesting Source of Biosurfactants

A new scientific hypothesis states that biosurfactants from cloud microorganism origin could change the surface tension of aerosols and thus the mode of precipitations. In order to check this hypothesis, our team has screened a collection of 480 microbial strains isolated from cloud waters for the production of biosurfactants and showed that 42% of these strains were producing such molecules. In the present work, we isolated and identified by LC-MS-MS lipopeptides produced from three strains issued from this screening. Viscosin and massetolide E (cyclic lipopeptides) were produced by Pseudomonas sp. PDD-14b-2, and syringafactins (linear lipopeptides) were produced by Xanthomonas campestris PDD-32b-52 and Pseudomonas syringae PDD-32b-74. The critical micelle concentration (CMC) of these biosurfactants was determined using the pendant drop method. Finally, two approaches of molecular dynamics were used to model the conformation of viscosin and syringafactin A at the water-air interface: one is based on all-atoms simulation (CHARMM force field), while the other one on coarse-grain (CG) simulation (MARTINI force field). To conclude, this work shows how the biodiversity of the cloud microbiota can be explored to search and produce biosurfactants of interest both for atmospheric sciences and also for biotechnological applications

Solution structures of the Bacillus cereus metallo-β-lactamase BcII and its complex with the broad spectrum inhibitor R-thiomandelic acid

Metallo-β-lactamases, enzymes which inactivate β-lactam antibiotics, are of increasing biological and clinical significance as a source of antibiotic resistance in pathogenic bacteria. In the present study we describe the high-resolution solution NMR structures of the Bacillus cereus metallo-β-lactamase BcII and of its complex with R-thiomandelic acid, a broad-spectrum inhibitor of metallo-β-lactamases. This is the first reported solution structure of any metallo-β-lactamase. There are differences between the solution structure of the free enzyme and previously reported crystal structures in the loops flanking the active site, which are important for substrate and inhibitor binding and catalysis. The binding of R-thiomandelic acid and the roles of active-site residues are defined in detail. Changes in the enzyme structure upon inhibitor binding clarify the role of the mobile β3–β4 loop. Comparisons with other metallo-β-lactamases highlight the roles of individual amino-acid residues in the active site and the β3–β4 loop in inhibitor binding and provide information on the basis of structure–activity relationships among metallo-β-lactamase inhibitors

Le problème Vareille(s) - Vazeille(s)

Nauton Pierre. Le problème Vareille(s) - Vazeille(s). In: Revue Internationale d'Onomastique, 3e année N°1, mars 1951. pp. 9-30

Sand supply, sources and evolution of the mid-Carboniferous Clare Basin, western Ireland: insights from multi-proxy provenance approaches

Sedimentary provenance analysis aims to improve the understanding of all factors associated with sediment production, transport and deposition. This has implications for a wide range of geosciences, helping towards reconstructing palaeogeography, palaeodrainage, and palaeoenvironment. However, multiple factors hinder optimum interpretation of provenance signals in sediments and sedimentary rocks. Some of these factors are investigated in this study, including the impacts of sedimentary recycling and sediment storage in the hinterland, prior to final deposition. This project applies a multi-proxy provenance approach to ancient sandstones from the mid-Carboniferous Clare Basin, western Ireland, to answer key provenance analysis questions and also to better constrain sedimentary routing and sources, basin infill, and palaeogeographic evolution. A large provenance dataset is presented here, comprising zircon U-Pb geochronology data from 13 samples (1624 grains), apatite U-Pb geochronology and trace element results from 10 samples (587 grains), heavy mineral analysis of 31 samples and standard petrographic analysis of 57 samples. The use of zircon and apatite U-Pb geochronology, heavy minerals analysis, apatite trace elements, and petrographic analysis is proven a powerful combination in the identification of sedimentary recycling in mineralogically mature sandstones. The results enable the identification of multiple source terranes supplying the sandstones of the Clare Basin. A major first cycle southern peri-Gondwanan associated input is identified. Additionally, polycyclic zircon (of Laurentian and Caledonian affinity) and apatite (Caledonian affinity) are established as ultimately being derived from the north but recycled through Old Red Sandstone sedimentary basins to the south (e.g. Dingle and Munster basins). Sedimentary recycling is therefore clearly favoured over intensive first cycle chemical weathering, to explain the mineralogical maturity of sandstones in the Clare Basin. The multi-proxy provenance approach identifies sedimentary sourcing in the Clare Basin as being continuously from the WSW-SSW throughout the entire sampled stratigraphy. Comparing provenance signals from the entire basin, both temporally and spatially, using detrital geochronology and heavy mineral indices, enables a better understanding of hinterland and shelf configuration evolution. Furthermore, southern hinterland uplift, linked with the Variscan Orogeny, is envisaged to impact supply during the later infill of the Clare Basin. In addition, heavy mineral indices in Tullig Cyclothem deltaic sandstones indicate a link between detrital mineralogy, sedimentary facies and sediment pre-depositional history. Relatively higher apatite-tourmaline index values are seen in channelised sandstones compared to sandstones associated with mouth bar and interdistributary bay facies. The apatite-tourmaline index highlights variations in the extent of chemical weathering experienced by the sediment prior to deposition. Such findings likely indicate that chemical weathering occurring prior to deposition is dependent on the sediment residence time in the hinterland and this signal appears to carry through to ultimate deposition. This highlights the potential of this specific index for use in reconstructing palaeoweathering and palaeoclimate at a deep-geological time scale. This project advances the utility of provenance analysis and highlights the need for a multi-proxy provenance approach to fully understand sedimentary routing. For the first time, the Clare Basin infill has been fully constrained through a multi-proxy provenance approach. Learnings from this case study from a well-known Irish sedimentary basin can be applied to other sedimentary successions, with a specific applicability to quartz-rich sedimentary rocks

Sand supply, sources and evolution of the mid-Carboniferous Clare Basin, western Ireland: insights from multi-proxy provenance approaches

Sedimentary provenance analysis aims to improve the understanding of all factors associated with sediment production, transport and deposition. This has implications for a wide range of geosciences, helping towards reconstructing palaeogeography, palaeodrainage, and palaeoenvironment. However, multiple factors hinder optimum interpretation of provenance signals in sediments and sedimentary rocks. Some of these factors are investigated in this study, including the impacts of sedimentary recycling and sediment storage in the hinterland, prior to final deposition. This project applies a multi-proxy provenance approach to ancient sandstones from the mid-Carboniferous Clare Basin, western Ireland, to answer key provenance analysis questions and also to better constrain sedimentary routing and sources, basin infill, and palaeogeographic evolution. A large provenance dataset is presented here, comprising zircon U-Pb geochronology data from 13 samples (1624 grains), apatite U-Pb geochronology and trace element results from 10 samples (587 grains), heavy mineral analysis of 31 samples and standard petrographic analysis of 57 samples. The use of zircon and apatite U-Pb geochronology, heavy minerals analysis, apatite trace elements, and petrographic analysis is proven a powerful combination in the identification of sedimentary recycling in mineralogically mature sandstones. The results enable the identification of multiple source terranes supplying the sandstones of the Clare Basin. A major first cycle southern peri-Gondwanan associated input is identified. Additionally, polycyclic zircon (of Laurentian and Caledonian affinity) and apatite (Caledonian affinity) are established as ultimately being derived from the north but recycled through Old Red Sandstone sedimentary basins to the south (e.g. Dingle and Munster basins). Sedimentary recycling is therefore clearly favoured over intensive first cycle chemical weathering, to explain the mineralogical maturity of sandstones in the Clare Basin. The multi-proxy provenance approach identifies sedimentary sourcing in the Clare Basin as being continuously from the WSW-SSW throughout the entire sampled stratigraphy. Comparing provenance signals from the entire basin, both temporally and spatially, using detrital geochronology and heavy mineral indices, enables a better understanding of hinterland and shelf configuration evolution. Furthermore, southern hinterland uplift, linked with the Variscan Orogeny, is envisaged to impact supply during the later infill of the Clare Basin. In addition, heavy mineral indices in Tullig Cyclothem deltaic sandstones indicate a link between detrital mineralogy, sedimentary facies and sediment pre-depositional history. Relatively higher apatite-tourmaline index values are seen in channelised sandstones compared to sandstones associated with mouth bar and interdistributary bay facies. The apatite-tourmaline index highlights variations in the extent of chemical weathering experienced by the sediment prior to deposition. Such findings likely indicate that chemical weathering occurring prior to deposition is dependent on the sediment residence time in the hinterland and this signal appears to carry through to ultimate deposition. This highlights the potential of this specific index for use in reconstructing palaeoweathering and palaeoclimate at a deep-geological time scale. This project advances the utility of provenance analysis and highlights the need for a multi-proxy provenance approach to fully understand sedimentary routing. For the first time, the Clare Basin infill has been fully constrained through a multi-proxy provenance approach. Learnings from this case study from a well-known Irish sedimentary basin can be applied to other sedimentary successions, with a specific applicability to quartz-rich sedimentary rocks