Characterization of flagellar-specific sigma factor FliA in Sphingopyxis granuli TFA

Motivation: Sigma factors are RNA polymerase subunits which play a crucial role in the transcriptional regulation of bacterial gene expression. These dissociable proteins bind to RNA polymerase controlling promoter recognition and thus, gene expression (Francez-charlot et al., 2015). Previous studies in Alphaproteobacteria identified a sigma factor FliA as a key transcriptional regulator of chemotaxis and flagella biogenesis by controlling the expression of genes involved in flagellin biosynthesis, an essential structural protein which forms flagella filament (Maruyama et al., 2015). Sphingopyxis granuli TFA is a Gram-Negative Alphaproteobacteria very interesting since is one of the few strains able to grow on the organic solvent tetralin as a sole carbon and energy source and able to grow respiring nitrate under anaerobic conditions (García-Romero et al., 2016). The aim of this study is to construct and phenotypically characterize a fliA deletion mutant that help us to elucidate the function of FliA sigma factor and thus, the hierarchy of transcriptional regulation of flagellar genes, in Sphingopyxis granuli TFA.Methods: A fliA deletion mutant is being constructed using a DNA-recombination method based on a double-strand break caused by SceI nuclease. Firstly, flanking regions of fliA gene must be cloned in a multiple cloning site (MCS) of a non-replicative vector. At the same time, this MCS is flanked by two SceI target sites. Once this integrative vector is integrated into the chromosome and selected in wild-type TFA, a broad host range vector including SceI gene downstream of an inducible promoter must be introduced. A double-strand break is caused in the chromosome after the induction of SceI nuclease by 3-methylbenzoate and DNA will be repaired causing FliA gene deletion.Once fliA deletion mutant is constructed, a phenotypic characterization will be performed. In addition, both semi-quantitative PCR and Q-PCR assays will be used in order to confirm which genes are regulated by FliA in Sphingopyxis granuli TFA

Modelización de la curva de fluencia en condiciones de deformación en caliente del aluminio puro (99.87%)

A lo largo de la historia, la conformación en caliente ha sido utilizada para dar a los metales la forma deseada. Hoy en día, sin embargo, y gracias al avance en conocimiento de materiales, la deformación en caliente no sólo proporciona la geometría deseada sino las características mecánicas. Para ello es indispensable un adecuado diseño del proceso de termoconformado. Desde este punto de vista, la obtención de una ecuación constitutiva basada en modelos existentes para la fluencia en caliente del material y del aluminio en particular con una pureza del 99.87%, se convierte en una tarea primordial y que para nuestro caso en particular hemos hecho uso del Modelo de Strim, Mecking y Bergstrom. Para este propósito, los ensayos de deformación en caliente (compresión uniaxial) fueron llevados a cabo en un intervalo de velocidades de deformación de 10ˉ¹, 10ˉ² y 10ˉ³ sˉ¹ y a una temperatura de 250, 300, 350 y 400ºc previo tratamiento térmico de recosido a 400ºc durante 20 minutos con el fin de obtener una estructura homogénea (granos equiaxiales). Las curvas de fluencia o de estado estable fueron simuladas en un programa por ordenador que permitieron obtener importantes parámetros involucrados en la deformación en caliente tales como el término de endurecimiento por deformación U(.b)² y el término de ablandamiento por restauración dinámica ()

High resolution quantitative seismic imaging of a strike-slip fault with small vertical o set in clay-rocks from underground galleries. Experimental Platform of Tournemire, France.

Imaging tectonic faults with small vertical offsets in argilittes (clay-rock) using geophysical methods is challenging. In the context of deep radioactive waste disposals, the presence of such faults has to be assessed since they can modify the rock confining properties. In the Tournemire Experimental Platform (TEP, France), fault zones with small vertical offsets and complex shape have been identified from underground works. However, 3D high-resolution surface seismic methods have shown limitations in this context that led us to consider the detection and characterization of the faults directly from underground works. We investigate here the potential of seismic full waveform inversion (FWI) applied in a transmission configuration to image the clay-rock medium in a horizontal plane between galleries, and compare it with first-arrival traveltime tomography (FATT). Our objective is to characterize seismic velocities of a block of argilittes crossed by a subvertical fault zone with a small vertical offset. The specific measurement configuration allows us to neglect the influence of the galleries on the wave propagation and to simplify the problem by considering a 2D isotropic horizontal imaging domain. Our FWI scheme relies on a robust adaptation of early-arrival waveform tomography. The results obtained with FATT and FWI are in accordance and both correlate with the geological observations from the gallery walls and boreholes. We show that even though various simplifications are done in the inversion scheme and only a part of the data is used, FWI allows to get higher resolution images than FATT, and is especially less sensitive to the incomplete illumination as it uses also diffracted energy. The results provided in this study highlight the complexity of the fault zone, showing a complex interaction of the main fault system with a secondary system composed of decimetric fractures associated with the presence of water

Redox-Active Metallacarborane-Decorated Octasilsesquioxanes. Electrochemical and Thermal Properties

Polyanionic and electroactive hybrids based on octasilsesquioxanes bearing metallacarborane units are developed. They show remarkable solubility in organic solvents and outstanding thermal stability. The metallacarboranes act as independent units simultaneously undergoing the reversible redox process.We acknowledge support by MINECO [Grants CTQ2013- 44670-R, CTQ2012-32436, and CTQ2015-64436-P and the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496)] and Generalitat de Catalunya (Grant 2014/ SGR/149). J.C.-G. thanks to the CSIC for an intramural grant. V.S.-A. thanks MICINN (Grant CTQ2010-16237) for the FPI grant.Peer reviewe

EXTRACCIÓN DE ANTOCIANINAS A PARTIR DE LA CORONTA Y GRANO DE MAÍZ MORADO (Zea Mays L.) DE LA PROVINCIA DE TARATA - TACNA, PERÚ

Extraer el componente de color de la coronta o del grano de maíz morado (Zea mays L.) cultivado en la provincia de Tarata, equivale a obtener sus antocianinas; este fue el objetivo del presente trabajo. Se utilizó un diseño experimental con dos tratamientos y tres repeticiones; se realizaron análisis de humedad, acidez titulable, rendimiento del concentrado y contenido de antocianinas en las muestras obtenidas. Los resultados mostraron que la humedad estuvo entre 44,0947 a 51,4087%; la acidez cítrica de 1,8373 a 2,5566 g/L; el concentrado de antocianinas estuvo entre 0,9856 a 2,4747 %. Las antocianinas obtenidas del maíz morado cultivado en la provincia de Tarata, Tacna se encuentran en mayor cantidad en la coronta

Induced polarization of clay-sand mixtures: experiments and modelling

Frequency-domain induced polarization (IP) measurements consist of imposing an alternative sinusoidal electrical current (AC) at a given frequency and measuring the resulting electrical potential difference between two other non-polarizing electrodes. The magnitude of the conductivity and the phase lag between the current and the difference of potential can be expressed into a complex conductivity with the in-phase representing electromigration and a quadrature conductivity representing the reversible storage of electrical charges (capacitive effect) of the porous material. Induced polarization has become an increasingly popular geophysical method for hydrogeological and environmental applications [1]. These applications include for instance the characterization of clay materials used as permeability barriers in landfills or to contain various types of contaminants including radioactive wastes [2]. The goal of our study is to get a better understanding of the influence of the clay content, clay mineralogy, and pore water salinity upon complex conductivity measurements of saturated clay-sand mixtures in the frequency range ~ 1 mHz-12 kHz. The complex conductivity of saturated unconsolidated sand-clay mixtures was experimentally investigated using two types of clay minerals, kaolinite and smectite in the frequency range 1.4 mHz - 12 kHz. Four different types of sample were used, two containing mainly kaolinite (80% of the mass, the remaining containing 15% of smectite and 5% of illite/muscovite; 95% of kaolinite, 5% of illite/muscovite), and the two others containing mainly Na-smectite or Na-Ca-smectite (95% of the mass; bentonite). The experiments were performed with various clay contents (1, 5, 20, and 100 % in volume of the sand-clay mixture) and salinities (distilled water, 0.1 g/L, 1 g/L, and 10 g/L NaCl solution). In total, 44 saturated clay or clay-sand mixtures were prepared. Induced polarization measurements were performed with a cylindrical four-electrode sample-holder (cylinder made of PVC with 30 cm in length and 19 cm in diameter) associated with a SIP-Fuchs II impedance meter and non-polarizing Cu/CuSO4 electrodes (Figure 1). These electrodes were installed at 10 cm from the base of the sample holder and regularly spaced (each 90 degree). The results illustrate the strong impact of the Cationic Exchange Capacity (CEC) of the clay minerals upon the complex conductivity. The amplitude of the in-phase conductivity of the kaolinite-clay samples is strongly dependent to saturating fluid salinity (Figure 2) for all volumetric clay fractions, whereas the in-phase conductivity of the smectite-clay samples is quite independent on the salinity, except at the low clay content (5% and 1% of clay in volume). This is due to the strong and constant surface conductivity of smectite associated with its very high CEC. The quadrature conductivity increases steadily with the CEC and the clay content. We observe that the dependence on frequency of the quadrature conductivity of sand-kaolinite mixtures is more important than for sand-bentonite mixtures. For both types of clay, the quadrature conductivity seems to be fairly independent on the pore fluid salinity (Figure 2) except at very low clay contents (1% kaolinite-clay in volume). This is due to the constant surface site density of Na counter-ions in the Stern layer of clay materials [3]. At the lowest clay content (1%), the magnitude of the quadrature conductivity increases with the salinity, as expected for silica sands. In this case, the surface site density of Na counter-ions in the Stern layer increases with salinity [4]. The experimental data show good agreement with predicted values given by our Spectral Induced Polarization (SIP) model [4]. This complex conductivity model considers the electrochemical polarization of the Stern layer coating the clay particles and the Maxwell-Wagner polarization. We use the differential effective medium theory to calculate the complex conductivity of the porous medium constituted of the grains and the electrolyte. The SIP model includes also the effect of the grain size distribution upon the complex conductivity spectra. Interfacial parameters are estimated using the TLM of Sverjensky [5] for silica and the Donnan model of Tournassat and Appelo [6] for smectite

Carborane-stilbene dyads: influence of substituents and cluster isomers on the photoluminescence properties

Two novel styrene-containing meta-carborane derivatives substituted at the second carbon cluster atom (Cc) with either a methyl (Me), or a phenyl (Ph) group, are introduced herein alongside with a new set of stilbene-containing ortho- (o-) and meta- (m-) carborane dyads. The latter set of compounds has been prepared from styrenecontaining carborane derivatives via Heck coupling reaction. High regioselectivity has been achieved for these compounds by using a combination of palladium complexes [Pd2(dba)3]/[Pd(t-Bu3P)2] as a catalytic system, yielding exclusively E isomers. All compounds have been fully characterized and the crystal structures of seven of them analyzed by X-ray diffraction. The absorption spectra of these compounds are similar to those of their respective fluorophore groups (styrene or stilbene), showing very low influence of the substituent (Me or Ph) linked to the second Cc atom or the cluster isomer (o- or m-). On the other hand, fluorescence spectroscopy revealed high emission intensities for Me-o-carborane derivatives, whereas their Ph-o-carborane analogues evidenced an almost total lack of fluorescence, confirming the significant role of the substituent bound to the adjacent Cc in o-carboranes. In contrast, all the m-carborane derivatives display similar photoluminescence (PL) behavior regardless of the substituent attached to the second Cc, demonstrating its small influence on the emission properties. Additionally, m-carborane derivatives are significantly more fluorescent than their o- counterparts, reaching quantum yield values as high as 30.2%. Regarding the solid state emission, only stilbene-containing Ph-o-carborane derivatives, which showed very low fluorescence in solution, exhibited a notable PL emission in films attributed to the aggregation-induced emission. DFT calculations were performed to successfully complement the photoluminescence studies, supporting the experimentally observed photophysical behavior of the styrene and stilbene-containing carborane derivatives. In conclusion, in this work is proved that it is possible to tailor the PL properties of the carborane-stilbene dyads by changing the Cc substituent and the carborane isomer.This work has been supported by Ministerio de Economía y Competitividad, MINECO, (CTQ2013-44670-R and CTQ2013-41339-P), and Generalitat de Catalunya (2014/SGR/149). Theoretical calculations have been achieved using computers from the Centro Técnico de Informática del Consejo Superior de Investigaciones Ciéntificas (CTI-CSIC). ICMAB acknowledges financial support from the MINECO, through the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV- 2015-0496).Peer reviewe

Étude par couplage CIN-MEB de l'influence de la microstructure sur les déformations par dessiccation de l'argilite de Tournemire

La relation entre les déformations par dessiccation de l’argilite de Tournemire et les propriétés texturales de la roche a été étudiée par un nouveau montage expérimental. Celui-ci se déroule en deux phases : la première utilise la méthode de corrélation d’images numériques (CIN) et la seconde la microscopie électronique à balayage (MEB). L’intérêt de cette manipulation est de pouvoir quantifier l’influence de la microstructure de l’argilite sur des déformations provoquées par des variations d’humidités. Dans une enceinte étanche, un échantillon provenant du forage FD90 du tunnel de Tournemire a été soumis à cycle de saturation-désaturation entre 98 et 33% d’humidité (98-33-98-33). L’échantillon se présente sous la forme d’un cube de 20x20x20mm3 et est filmé par deux caméras. La première caméra filme un champ large sur une face entière (25x20mm²) tandis que la seconde filme un champ zoomé (5.5x4.1mm²) sur une autre face. Le champ zoomé est ensuite analysé au MEB afin d’établir une cartographie des minéraux en électrons rétrodiffusés, qui sera comparée aux champs de déformations obtenus par CIN à partir des images des caméras. Ce montage expérimental permet d’étudier les champs de déformations dans deux directions (approximation du phénomène en 3D) à deux échelles différentes (millimétrique à micrométrique) avec la microstructure et la teneur en eau de la roche

A 3D Peptide/[60]Fullerene Hybrid for Multivalent Recognition

Multivalent ligand presentation is a powerful strategy for the development of specific binders and inhibitors. Peptide/[60]fullerene hybrids have now been synthesized that exploit the complete substitution of the fullerene scaffold to afford globular structures presenting twelve copies of a peptide ligand for the recognition of E-selectin. Fully substituted peptide/[60]fullerene hexakis-adducts offer an excellent opportunity for multivalent protein recognition. In contrast to monofunctionalized fullerene hybrids, peptide/[60]fullerene hexakis-adducts display multiple copies of a peptide in close spatial proximity and in the three dimensions of space. High affinity peptide binders for almost any target can be currently identified by in vitro evolution techniques, often providing synthetically simpler alternatives to natural ligands. However, despite the potential of peptide/[60]fullerene hexakis-adducts, these promising conjugates have not been reported to date. Here we present a synthetic strategy for the construction of 3D multivalent hybrids that are able to bind with high affinity the E-selectin. The here synthesized fully substituted peptide/[60]fullerene hybrids and their multivalent recognition of natural receptors constitute a proof of principle for their future application as functional biocompatible materialsThis work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [SAF2017-89890-R, PCI2019-103400, PID2020-117143RB-I00, PID2020-114653RB-I00 and PID2020-115120GB-I00], Xunta de Galicia (ED431C 2017/25 and Centro singular de investigación de Galicia accreditation 2019–2022, ED431G 2019/03) and the European Commission (EC) (European Regional Development Fund-ERDF). J.M. thanks the ERC-STG (DYNAP, 677786), ERC-POC (TraffikGene, 838002), Xunta de Galicia (Oportunius Program) and Human Frontier Science Programme Young Investigator Grant (RGY0066/2017) for funding. J.J.R. received a Beatriz Galindo Grant (BEAGAL18-00051) by the Spanish Ministerio de Universidades. I.G. received predoctoral fellowships (ED481A-2018/116 and FPU17/00941). J.C.-G. thanks the Comunidad de Madrid Atracción de Talento program (2018-T2/BMD-10275)S