HCO3- enrichment causes cytosolic NO3- efflux in Posidonia oceanica leaf cells

Posidonia oceanica is a seagrass, the only group of vascular plants to colonize the marine environment. Seawater is an extreme yet stable environment, characterized by high salinity, alkaline pH and low availability of essential nutrients, such as nitrate or phosphate. In addition, in aquatic environments the supply of CO2 for the photosynthesis is limited by diffusion and therefore many aquatic plants use HCO3- as the inorganic carbon source for photosynthesis. Previous results have shown that Na+ -dependent transport systems operate on the plasma membrane of P. oceanica mesophyll leaf cells for the high-affinity NO3-, Pi or amino acids uptake. Also, a direct transport of HCO3- driven by H+ has been found in this species that provides inorganic carbon for photosynthesis and could be a significant component of a carbon concentrating mechanism in this species. Interestingly, this HCO3- direct uptake caused the efflux of chloride from the cytosol, probably through S-type anion channels, pointing that other anions could also be removed from the cytosol. This hypothesis could be relevant in the case of NO3-, since the decrease of cytosolic NO3- in response to HCO3- enrichment could limit N-assimilation. Here we analyse the effect of HCO3- increase on NO3- uptake and cytosolic homeostasis in P. oceanica. Enrichment of natural seawater with 3 mM HCO3- evokes the on-going decrease of cytosolic NO3-, from 5.7 ± 0.2 to 4.8 ± 0.7 mM after 40 min of treatment. The incubation of P. oceanica leaf pieces in 3 mM HCO3- NSW causes an initial increase of NO3- concentration in the medium. Maximum efflux (21 nmol NO3- gFM-1 min-1) occurs within the first minute of incubation. Then, external NO3- is depleted from the medium at lower net uptake rate than the value observed in non HCO3- -enriched natural seawater. These results fit the hypothesis that HCO3- enrichment causes the nitrogen loose and could impair nitrogen assimilation promoting N biomass impoverishment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Spanish MINECO, projects BFU2017-85117-R and BIO2016-81957-RED

NRT2.5 a putative sodium dependent high affinity nitrate trasnporter of zostera marina l.

Seagrasses are the only group of vascular plants that recolonized the marine environment, possibly the most severe habitat shift ever accomplished by flowering plants. These plants have regained functions enabling them to thrive in liquid medium with an extremely high salinity (0.5 M Na+), high alkaline conditions (pH 8.2) and very low concentration of essential nutrients as NO3- or Pi. Despite this, seagrasses form one of the highest productive and widespread ecosystems of the planet (Larkum et al., 2006). Zostera marina was the first seagrass fully sequenced and its genome reveals important insights about this secondary adaption. Comparison with land plants indicates that less than 20 % of the genes families are specific in the genome of seagrasses. Thus, adaptation to marine environment seems to be due to molecular changes of the same family genes rather that the speciation of pre-existing genes. This appears to be the case of the high affinity nitrate transporter belonging to the NRT family. In contrast to terrestrial vascular plants, where NRT2 encode high affinity NO3- transporters that operate as H+ symporters, our electrophysiological analysis indicate that in Z. marina high affinity NO3- uptake is mediated by a Na+-dependent mechanism. A detailed analysis of the Z. marina genome indicates the presence of only one gene encoding for this type of transporter: Zosma70g00300.1. Phylogenetic analysis shows that this high affinity nitrate transporter is more related to NRT2.5 than to NTRT2.1, sharing a common ancestor with both, monocot and dicot plants. We have cloned Zosma70g00300.1 and the high-affinity nitrate transporter accessory protein NAR2 (Zosma63g00220.1) in order to characterize the specific transport mechanism mediated by these proteins in Z. marina. Thus, the putative Z. marina NRT2.5 transporter could have evolved to use Na+ as a driving ion, which might be an essential adaptation of seagrasses to colonize the marine environment.MICINN (BFU2017-85117-R; BIO2016-81957-REDT) Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of seawater inorganic carbon enrichment on NO3- transporter and reduction enzyme gene expression in Zostera marina leaves

In this work we have analysed the gene expression levels related to cytosolic nitrate homeostasis, including transporters and enzymes, in leaves of Zostera marina plants incubated in high HCO3- or in the absence of N. The expression levels of ZosmaNTR2, the only gene quoted as a high- affinity nitrate transporter belonging to NRT2 family in Z. marina genome, as well as its regulatory protein ZosmaNAR2, were induced in both conditions. Interestingly, expression levels of such genes were higher than the obtained for ZosmaCHL1 (ZosmaNPF6.3), which expression was lower in N-replete plants, but did not vary in response to HCO3-. These results suggest that the induction of the expression of the NO3- high-affinity transporter ZosmaNRT2 and its regulatory protein ZosmaNAR2 are the main response for the cytosolic NO3- decrease in both N-deficiency or in C-enrichment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

El civil law frente al precedente judicial vinculante: diálogos con académicos de América Latina y Europa

Este trabajo corresponde a parte de los resultados obtenidos en el marco de la ejecución del proyecto Fondecyt N° 1181066 (ANID, Chile), al cual los autores desean hacer presente su agradecimientoEl presente trabajo aborda el tema del precedente judicial vinculante. Para su ejecución, se usó como metodología la entrevista semiestructurada participando de ella un total de treinta y dos académicos de diez países de América Latina y Europa. Los resultados se estructuran en torno a los argumentos a favor y en contra del precedente como posición teórica; a narrar cómo se comportan los tribunales vértice y el resto frente a los precedentes; y, finalmente, a conocer los obstáculos que impiden seguir correctamente los precedentes.This paper addresses binding judicial precedent. The semistructured interview was used as a methodology for execution and a total of thirty-two academics, from ten countries in Latin America and Europe, participated of it. The results are structured around the arguments for and against precedent as a theoretical position; to narrate how vertex courts and inferior courts behave on precedents; and finally, to know the roadblocks that prevent following precedent correctly

Deficits in coordinated neuronal activity and network topology are striatal hallmarks in Huntington's disease.

Background. Network alterations underlying neurodegenerative diseases often precede symptoms and functional deficits. Thus, their early identification is central for improved prognosis. In Huntington's disease (HD), the cortico-striatal networks, involved in motor function processing, are the most compromised neural substrate. However, whether the network alterations are intrinsic of the striatum or the cortex is not fully understood. Results In order to identify early HD neural deficits, we characterized neuronal ensemble calcium activity and network topology of HD striatal and cortical cultures. We used large-scale calcium imaging combined with activity-based network inference analysis. We extracted collective activity events and inferred the topology of the neuronal network in cortical and striatal primary cultures from wild-type and R6/1 mouse model of HD. Striatal, but not cortical, HD networks displayed lower activity and a lessened ability to integrate information. GABAA receptor blockade in healthy and HD striatal cultures generated similar coordinated ensemble activity and network topology, highlighting that the excitatory component of striatal system is spared in HD. Conversely, NMDA receptor activation increased individual neuronal activity while coordinated activity became highly variable and undefined. Interestingly, by boosting NMDA activity, we rectified striatal HD network alterations. Conclusions. Overall, our integrative approach highlights striatal defective network integration capacity as a major contributor of basal ganglia dysfunction in HD and suggests that increased excitatory drive may serve as a potential intervention. In addition, our work provides a valuable tool to evaluate in vitro network recovery after treatment intervention in basal ganglia disorders

Dynamic photopolymerization produces complex microstructures on hydrogels in a moldless approach to generate a 3D intestinal tissue model

Epithelial tissues contain three-dimensional (3D) complex microtopographies that are essential for proper performance. These microstructures provide cells with the physicochemical cues needed to guide their self-organization into functional tissue structures. However, most in vitro models do not implement these 3D architectural features. The main problem is the availability of simple fabrication techniques that can reproduce the complex geometries found in native tissues on the soft polymeric materials required as cell culture substrates. In this study reaction-diffusion mediated photolithography is used to fabricate 3D microstructures with complex geometries on poly(ethylene glycol)-based hydrogels in a single step and moldless approach. By controlling fabrication parameters such as the oxygen diffusion/depletion timescales, the distance to the light source and the exposure dose, the dimensions and geometry of the microstructures can be well-defined. In addition, copolymerization of poly(ethylene glycol) with acrylic acid improves control of the dynamic reaction-diffusion processes that govern the free-radical polymerization of highly-diluted polymeric solutions. Moreover, acrylic acid allows adjusting the density of cell adhesive ligands while preserving the mechanical properties of the hydrogels. The method proposed is a simple, single-step, and cost-effective strategy for producing models of intestinal epithelium that can be easily integrated into standard cell culture platfor

Biodegradable nanofibrous scaffolds as smart delivery vehicles for amino acids

The encapsulation of amino acids (AAs) and their correct preservation before they are ingested are challenging tasks. Nonpolar (l-alanine and l-phenylalanine), polar (l-cysteine hydrochloride and l-asparagine), and charged (l-lysine hydrochloride and l-aspartic acid) AAs were loaded into biodegradable and nontoxic poly(tetramethylene succinate) (PE44) nanofibers (NFs) with electrospinning. The loading of AAs considerably affected the morphology, topography, thermal properties, and wettability of the PE44 NFs. Furthermore, although the AAs crystallized in a phase separated from the polymeric matrix, the distribution of such crystals changed into PE44 NFs and depended on their chemical nature. Release assays in enzyme-free solutions provided evidence that very significant amounts of AAs were retained in the NFs after 7 days, whereas assays in the lipase-containing solution (because lipase performs essential roles in the digestion) showed almost complete release after a few hours. Lipase preferentially attacked the PE44 regions responsible for the retention of AAs in the biphasic system and favored the almost immediate release of the biomolecules. The results displayed in this study, combined with the biocompatibility, biodegradability, and potential use of the PE44 NFs as edible nonnutritional elements, suggest that the loaded PE44–AA NFs could be used to supply essential and conditional AAs.Peer ReviewedPostprint (author's final draft

New Models Used to Determine the Dioxins Total Amount and Toxicity (TEQ) in Atmospheric Emissions from Thermal Processes

In order to reduce the calculation effort during the simulation of the emission of polychlorinated dibenzo-p-dioxins and furans (PCDD/F) during municipal solid waste incineration, minimizing the number of simulated components is mandatory. For this purpose, two new multilinear regression models capable of determining the dioxins total amount and toxicity of an atmospheric emission have been adjusted based on previously published ones. The new source of data used (almost 200 PCDD/F analyses) provides a wider range of application to the models, increasing also the diversity of the emission sources, from industrial and laboratory scale thermal processes. Only three of the 17 toxic congeners (1,2,3,6,7,8-HxCDD, 2,3,7,8-TCDF and OCDF), whose formation was found to be linearly independent, were necessary as inputs for the models. All model parameters have been statistically validated and their confidence intervals have been calculated using the Bootstrap method. The resulting coefficients of determination (R2) for the models are 0.9711 ± 0.0056 and 0.9583 ± 0.0085; its root mean square errors (RMSE) are 0.2115 and 0.2424, and its mean absolute errors (MAE) are 0.1541 and 0.1733 respectively.Juan A. Conesa and Nuria Ortuño acknowledge the support for this work by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain). Damià Palmer thanks IQS—Universitat Ramon Llull for its financial support

Simulating Gaia performances on white dwarfs

One of the most promising space missions of ESA is the astrometric satellite Gaia, which will provide very precise astrometry and multicolour photometry, for all 1.3 billion objects to V~20, and radial velocities with accuracies of a few km/s for most stars brighter than V ~ 17. Consequently, full homogeneous six-dimensional phase-space information for a huge number of stars will become available. Our Monte Carlo simulator has been used to estimate the number of white dwarfs potentially observable by Gaia. From this we assess which would be the white dwarf luminosity functions which Gaia will obtain and discuss in depth the scientific returns of Gaia in the specific field of white dwarf populations. Scientific attainable goals include, among others, a reliable determination of the age of the Galactic disk, a better knowledge of the halo of the Milky Way and the reconstruction of the star formation history of the Galactic disk. Our results also demonstrate the potential impact of a mission like Gaia in the current understanding of the white dwarf cooling theory.Comment: 13 pages, 17 figures, accepted for publication in MNRA