281 research outputs found

    Durabilidad natural del carrizo (Phragmites australis) frente a organismos xilófagos: relación con otras especies forestales

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    This work presents the research carried out to determine the natural durability of reed (Phragmites communis) from the Fertö region of Hungary against wood decay organisms, with the objective of obtaininig information to be used as a constituent element in outdoor use, and in particular, in a viable and sustainable motorway noise barrier. Phragmites communis is a large perennial grass of considerable size which grows in temperate and tropical wetland zones throughout the world. Its growth is expansive and it frequently invades wetlands where it competes with the native species and therefore requires regular removal so that an excess of organic material is not produced in the habitat. In addition, the invasion by this plant of polluted waters also appears to have a beneficial effect, so it can be used as a natural water purifier and thus has a potential use as a purification method for wetlands contaminated by agricultural practices. Due to the need for its periodic extraction, its possible use as a construction material, although in a secondary role, gives it an added value for which further scientific study is required. In the absence of a reference Standard and being reed a lignocellulose material, the study of its natural durability has been based on the existing Standards for wood. The tests show that Hungarian reed has a high level of durability against some fungi and other wood decay organisms. Key words: Reed, sustainable noise barrier, durability, wood decay organisms.Este trabajo presenta las investigaciones llevadas a cabo para determinar la durabilidad natural de Phragmites communis procedente de la región de Fertö, Hungría, frente a organismos xilófagos, con el objetivo de ser utilizado en el exterior, y en particular, como parte fundamental de una barrera acústica sostenible para carretera. Phragmites communis es una gramínea de gran tamaño que se desarrolla en humedales de zonas templadas y tropicales de todo el mundo. Suele utilizarse como herramienta natural para la depuración de aguas, y es especialmente relevante su uso potencial como depurador de humedales contaminados por las prácticas agrícolas. Debido a la necesidad de extraerlo periódicamente, las investigaciones que se realicen para su posible uso como material de construcción ofrecerían un valorañadido. Dada la ausencia de una normativa de referencia, y dado que el carrizo es un material lignocelulósico, el estudio de su durabilidad natural se ha enfocado a partir de las normas existentes para madera. Los ensayos demuestran que la durabilidad del carrizo húngaro es alta frente a algunos hongos y organismos xilófagos

    Plant Traits and Phylogeny Predict Soil Carbon and Nutrient Cycling in Mediterranean Mixed Forests

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    Soil functioning is closely linked to the interactions between biological communities with the physical environment. Yet, the impact of plant community attributes on metabolic processes promoting soil nutrient cycling remains largely unknown. We hypothesized that the plant community acts as a regulating agent of nutrient mobilization in soils according to the phylogenetic and morpho-functional traits of plant species of which it is composed. Rhizosphere soils were collected in autumn and spring under 32 tree and shrub species in two Mediterranean mixed forests (four plots in each) located in southern Spain, and nine soil enzymatic activities related to C, N and P mobilization were assessed. Phylogeny and morpho-functional traits of plant species were recorded and their imprint in soil enzymatic activities across forests was determined. The results showed a plant phylogenetic signal for N mobilization in both forests, while it varied across forests for non-labile C and P mobilization. The plant phylogenetic signals were primarily driven by lineages that diversified through the Miocene, about 25 Myr ago. In addition, leaf traits and plant’s mycorrhizal type explained soil enzymatic activities independently from phylogeny. C and P mobilization increased under ectomycorrhizal plants, whilst enhanced N mobilization did occur under arbuscular mycorrhizal ones. The plant community composition led to a different carbon and nutrient mobilization degree, which in turn was mediated by distinct microbial communities mirroring differentiated resource-acquisition strategies of plants. Our results highlight the role of plant traits and mycorrhizal interactions in modulating carbon and nutrient cycling in Mediterranean mixed forest soils.CRUE-CSIC Springer Natur

    In vitro Susceptibility and Evaluation of Techniques for Understanding the Mode of Action of a Promising Non-antibiotic Citrus Fruit Extract Against Several Pathogens

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    Copyright © 2019 de Nova, Carvajal, Prieto and Rubio. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.[EN] The screening for alternatives to antibiotics is an urgent need for the pharmaceutical industry. One of these alternatives seems to be the citrus fruit extracts, which are showing a significant antibacterial activity against Gram-negative and Gram-positive bacteria. One of these citrus extracts, named BIOCITRO®, is assessed in this study to elucidate its bacteriostatic and bactericidal effect and its mode of action on the important pathogens Campylobacter coli, C. jejuni, Escherichia coli, Salmonella enterica ssp. enterica, Clostridium difficile, C. perfringens, and Staphylococcus aureus. For most of the strains tested of these bacteria the product was bactericidal as well as bacteriostatic at the same concentration, and the minimum bactericidal concentrations ranged from 16 to 256 μg/mL. Regarding the mode of action, important changes in the permeability, structure, composition and morphology of the bacterial envelope were evidenced using flow cytometry, Fourier transform infrared spectroscopy and scanning electron microscopy. The main effect of the product was found over carbohydrates and polysaccharides, inducing the release of microvesicles by the cells in addition to other specific effects. During the study, the techniques used were evaluated to clarify their contribution to the knowledge of the mode of action of the product. The survival test elucidated whether the modifications displayed using other techniques affected the viability of the cells or on the contrary, the cells remained viable even with evident changes in their structure, composition or morphology. Flow cytometry showed that for some strains the proportion of cells detected with altered membrane permeability were higher than the number of non-viable cells, and therefore the damage did not affect the viability of some cells. On the contrary, some cells observed using scanning electron microscopy with no apparent damage, were demonstrated non-viable using the survival test, making this technique indispensable in studies of the mode of action of antimicrobials to make a correct interpretation of the data from other techniques.SIThe research was partly financed by PROBENA (2015/00119/001), the company commercializing BIOCITRO® in the EU, but without any influence over the experimental procedures neither results

    CHK1 expression in gastric cancer is modulated by p53 and RB1/E2F1: Implications in chemo/radiotherapy response

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    Radiation has a limited but relevant role in the adjuvant therapy of gastric cancer (GC) patients. Since Chk1 plays a critical function in cellular response to genotoxic agents, we aimed to analyze the role of Chk1 in GC as a biomarker for radiotherapy resistance. We analyzed Chk1 expression in AGS and MKN45 human GC cell lines by RT-QPCR and WB and in a small cohort of human patient’s samples. We demonstrated that Chk1 overexpression specifically increases resistance to radiation in GC cells. Accordingly, abrogation of Chk1 activity with UCN-01 and its expression with shChk1 increased sensitivity to bleomycin and radiation. Furthermore, when we assessed Chk1 expression in human samples, we found a correlation between nuclear Chk1 accumulation and a decrease in progression free survival. Moreover, using a luciferase assay we found that Chk1’s expression is controlled by p53 and RB/E2F1 at the transcriptional level. Additionally, we present preliminary data suggesting a posttranscriptional regulation mechanism, involving miR-195 and miR-503, which are inversely correlated with expression of Chk1 in radioresistant cells. In conclusion, Chk1/microRNA axis is involved in resistance to radiation in GC, and suggests Chk1 as a potential tool for optimal stratification of patients susceptible to receive adjuvant radiotherapy after surgeryThis work was supported by Instituto de Salud Carlos III–Fondo de Investigación Sanitaria (PS09/1988 to ISP; PI11-00949, pI014-1495 and Feder Funds to RP); Comunidad Autónoma de Madrid-Universidad Autónoma de Madrid (CCG10-UAM/BIO-5871 to ISP); Fundación Leticia Castillejo Castillo and Ministerio de Ciencia e Innovación (SAF2012-30862 to RSP), Spain

    The relative abundance of fecal bacterial species belonging to the Firmicutes and Bacteroidetes phyla is related to plasma levels of bile acids in young adults

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    The online version contains supplementary material available at https://doi.org/10.1007/s11306-023-02016-8.Funding for open access publishing: Universidad de Granada/CBUA. The study was supported by the Spanish Ministry of Economy and Competitiveness via Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III (PI13/01393) and PTA 12264-I, Retos de la Sociedad (DEP2016-79512-R), and European Regional Development Funds (ERDF), by the Spanish Ministry of Education (FPU16/05159, FPU16/02828, FPU17/01523 and FPU19/01609), the Fundacion Iberoamericana de Nutricion (FINUT), the University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (UCEES), AstraZeneca HealthCare Foundation, and by the Junta de Andalucia, Consejeria de Economia, Conocimiento, Empresas y Universidad (ref. P18-RT-4455), the Chinese Scholarship Council (CSC, No. 201707060012 to XD), Fundacion Alfonso Martin Escudero and Maria Zambrano fellowship by the Ministerio de Universidades y la Union Europea -NextGenerationEU (RR_C_2021_04). We would like to thank the team of Data Integration Center of University Medicine Magdeburg for local data-analysis solutions; they are supported by MIRACUM and funded by the German Federal Ministry of Education and Research (BMBF) within the "Medical Informatics Funding Scheme" (FKZ 01ZZ1801H). This study is part of a Ph.D. thesis conducted within the Biomedicine Doctoral Studies Program of the University of Granada, Spain. AL was supported by the funds from European Commission through the "European funds for regional development" (EFRE) Project ID: ZS/2018/11/95324.Background Gut bacteria play a crucial role in the metabolism of bile acids (BA). Whether an association exists between the fecal microbiota composition and circulating BA levels in humans is poorly understood. Here, we investigated the relationship between fecal microbiota diversity and composition with plasma levels of BA in young adults. Methods Fecal microbiota diversity/composition was analyzed with 16S rRNA sequencing in 80 young adults (74% women; 21.9 +/- 2.2 years old). Plasma levels of BA were measured using liquid chromatography-tandem mass spectrometry. PERMANOVA and Spearman correlation analyses were used to investigate the association between fecal microbiota parameters and plasma levels of BA. Results Fecal microbiota beta (P = 0.025) and alpha diversity indexes of evenness (rho = 0.237, P = 0.033), Shannon (rho = 0.313, P = 0.004), and inverse Simpson (rho = 0.283, P = 0.010) were positively associated with plasma levels of the secondary BA glycolithocholic acid (GLCA). The relative abundance of genera belonging to the Firmicutes and Bacteroidetes phyla was positively correlated with plasma levels of GLCA (all rho = 0.225, P = 0.049). However, the relative abundance of species from Firmicutes and Bacteroidetes phyla were negatively correlated with plasma levels of primary and secondary BA (all rho = - 0.220, P = 0.045), except for the relative abundance of Bacteroides vulgatus, Alistipes onderdonkii, and Bacteroides xylanisolvens species (Bacteroidetes phylum) that were positively correlated with the plasma levels of GLCA. Conclusions The relative abundance of specific fecal bacteria species is associated with plasma levels of BA in young adults. However, further investigations are required to validate whether the composition of the gut microbiota can regulate the plasma concentrations of BA in humans.Universidad de Granada/CBUASpanish Ministry of Economy and Competitiveness via Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III PI13/01393Retos de la Sociedad DEP2016-79512-REuropean CommissionSpanish Government FPU16/05159, FPU16/02828, FPU17/01523, FPU19/01609Fundacion Iberoamericana de Nutricion (FINUT)University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (UCEES)AstraZenecaJunta de Andalucia P18-RT-4455China Scholarship Council 201707060012Ministerio de Universidades y la Union Europea -Next Generation EU RR_C_2021_04MIRACUMFederal Ministry of Education & Research (BMBF) FKZ 01ZZ1801HUniversity of Granada, SpainEuropean Commission Joint Research Centre ZS/2018/11/9532

    Reductive Hydrogenation of Sulfido-Bridged Tantalum Alkyl Complexes: A Mechanistic Insight

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    Hydrogenolysis of a series of alkyl sulfido-bridged tantalum(IV) dinuclear complexes [Ta(?5-C5Me5)R(?-S)]2 [R = Me, nBu (1), Et, CH2SiMe3, C3H5, Ph, CH2Ph (2), p-MeC6H4CH2 (3)] has led quantitatively to the Ta(III) tetrametallic sulfide cluster [Ta(?5-C5Me5)(?3-S)]4 (4) along with the corresponding alkane. Mechanistic information for the formation of the unique low-valent tetrametallic compound 4 was gathered by hydrogenation of the phenyl-substituted precursor [Ta(?5-C5Me5)Ph(?- S)]2, which proceeds through a stepwise hydrogenation process, disclosing the formation of the intermediate tetranuclear hydride sulfide [Ta2(?5-C5Me5)2(H)Ph(?-S)(?3-S)]2 (5). Extending our studies toward tantalum alkyl precursors containing functional groups susceptible to hydrogenation, such as the allyl-and benzylsubstituted compounds [Ta(?5-C5Me5)(?3-C3H5)(?-S)]2 and [Ta(?5-C5Me5)(CH2Ph)(?-S)]2 (2), enables alternative reaction pathways en route to the formation of 4. In the former case, the dimetallic system undergoes selective hydrogenation of the unsaturated allyl moiety, forming the asymmetric complex [{Ta(?5-C5Me5)(?3-C3H5)}(?-S)2{Ta(?5-C5Me5)(C3H7)}] (6) with only one propyl fragment. Species 2, in addition to the hydrogenation of one benzyl fragment and concomitant toluene release, also undergoes partial hydrogenation and dearomatization of the phenyl ring on the vicinal benzyl unity to give a ?5-cyclohexadienyl complex [Ta2(?5-C5Me5)2(?-CH2C6H6)(?-S)2] (7). The mechanistic implications of the latter hydrogenation process are discussed by means of DFT calculationsComunidad de MadridUniversidad de AlcaláPrograma Estímulo a la Investigación de Jóvenes Investigadore

    N=N Bond Cleavage by Tantalum Hydride Complexes: Mechanistic Insights and Reactivity.

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    A series of dinuclear tantalum(IV) hydrides [{TaCpRX2}2(mu-H)2] (CpR = eta5-C5Me5, eta5-C5H4SiMe3, eta5-C5HMe4; X = Cl, Br) show the ability to promote the N=N bond cleavage in their reactions with azobenzene and benzo[c]cinnoline in absence of reducing reagents. Both, characterization of intermediate species and DFT studies point to a mechanism in two stages, in which the Ta-Ta bond splitting is key for the reduction of the N=N bond and its complete scission.Consorcio Madroño - Universidad de Alcal

    Solar velocity references from 3D HD photospheric models

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    The measurement of Doppler velocities in spectroscopic solar observations requires a reference for the local frame of rest. The rotational and radial velocities of the Earth and the rotation of the Sun introduce velocity offsets in the observations. Normally, good references for velocities are missing (e.g. telluric lines), especially in filter-based spectropolarimetric observations. We determine an absolute reference for line-of-sight velocities measured from solar observations for any heliocentric angle, calibrating the convective line shift of spatially-averaged profiles on quiet sun from a 3D hydrodynamical simulation. This method works whenever there is quiet sun in the field-of-view, and it has the advantage of being relatively insensitive to uncertainties in the atomic data. We carry out radiative transfer computations in LTE for selected C I and Fe I lines, whereas the Ca II infrared lines are synthesized in non-LTE. The degree of asymmetry and the line shifts, however, show a clear dependence on the heliocentric angle and the properties of the lines. The profiles at \mu = 1 are compared with observed profiles to prove their reliability, and they are tested against errors induced by the LTE calculations, inaccuracies in the atomic data and the 3D simulation. Theoretical quiet-sun profiles of lines commonly used by solar observers are provided to the community. Those can be used as absolute references for line-of-sight velocities. The limb effect is produced by the projection of the 3D atmosphere along the line of sight. We estimate the precision of the disk-center line shifts to be approximately 50 m s^-1, but the off-center profiles remain to be tested against observations.Comment: 9 pages, 9 figures, accepted for publication in Astronomy & Astrophysic
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