Gating-induced large aqueous volumetric remodeling and aspartate tolerance in the voltage sensor domain of Shaker K+ channels

Indexación: Scopus.ACKNOWLEDGMENTS. We thank Chris Lingle and Yu Zhou (Washington University) for critical reading of the manuscript and Victoria Prado for Xenopus care and oocyte preparation. We also thank Millennium Scientific Initiative P029-022-F. This work was supported by Fondecyt Postdoctoral Grants 3170599 (to I.D.-F.) and 3160321 (to H.M.).Neurons encode electrical signals with critically tuned voltage-gated ion channels and enzymes. Dedicated voltage sensor domains (VSDs) in these membrane proteins activate coordinately with an unresolved structural change. Such change conveys the transmembrane translocation of four positively charged arginine side chains, the voltage-sensing residues (VSRs; R1–R4). Countercharges and lipid phosphohead groups likely stabilize these VSRs within the low-dielectric core of the protein. However, the role of hydration, a sign-independent charge stabilizer, remains unclear. We replaced all VSRs and their neighboring residues with negatively charged aspartates in a voltage-gated potassium channel. The ensuing mild functional effects indicate that hydration is also important in VSR stabilization. The voltage dependency of the VSR aspartate variants approached the expected arithmetic summation of charges at VSR positions, as if negative and positive side chains faced similar pathways. In contrast, aspartates introduced between R2 and R3 did not affect voltage dependence as if the side chains moved outside the electric field or together with it, undergoing a large displacement and volumetric remodeling. Accordingly, VSR performed osmotic work at both internal and external aqueous interfaces. Individual VSR contributions to volumetric works approached arithmetical additivity but were largely dissimilar. While R1 and R4 displaced small volumes, R2 and R3 volumetric works were massive and vectorially opposed, favoring large aqueous remodeling during VSD activation. These diverse volumetric works are, at least for R2 and R3, not compatible with VSR translocation across a unique stationary charge transfer center. Instead, VSRs may follow separated pathways across a fluctuating low-dielectric septum. © National Academy of Sciences. All rights reserved.https://www.pnas.org/content/115/32/820

Malalties immunomediades (immunopatologia) en el moment actual

Sota el terme de malalties immunomediades (MIM) s'agrupen totes aquelles malalties que tenen la causa de la malaltia en el sistema immunitari més que no pas la solució, com tothom espera del sistema encarregat del manteniment de la integritat de l'individu front a les infeccions. Així, autoimmunitat, immunoquímica, al·lèrgia, immunoteràpia i immunodeficiències serien els cinc grans subgrups d'aquest ampli concepte de MIM. En relació amb el diagnòstic i tractament de les MIM s'encunya el terme immunopatologia per referir-se a l'àrea de suport al diagnòstic per a aquestes malalties. Els avenços en el coneixement, diagnòstic i fins i tot tractament de les MIM són (després dels relacionats amb el coneixement de la genètica i el càncer) l'àrea biomèdica en què més aportacions s'estan fent en les darreres dècades.The term immune-mediated diseases (IMDs) groups together all the illnesses for which the cause is in the immune system rather than the solution as one would expect from the system in charge of upholding the integrity of individuals in the face of infections. Autoimmunity, immunochemistry, allergy, immunotherapy and immunodeficiencies are the 5 major subgroups of this broad concept of IMDs. When it comes to the diagnosis and treatment of IMDs, the term immunopathology has been coined to refer to the area for support in the diagnosis of such pathologies. Progress in the understanding, diagnosis and even treatment of IMDs (after knowledge of genetics and cancer) is the area in which most biomedical contributions have been made in recent decades

Luxación acromio-clavicular posterior con fractura clavicular asociada

Se presenta un caso infrecuente de luxación acromio- clavicular posterior asociada a una fractura de tercio medio clavicular ipsilateral en un varón de 17 años. El diagnóstico se basa en la sospecha clínica y en las pruebas de imagen, siendo la TAC de particular utilidad. La reducción abierta y fijación coraco-clavicular con resección del extremo distal clavicular dio excelentes resultados. Se compara el tratamiento realizado con otros publicados, realizando una revisión de la literatura al respecto.An unusual case of combined posterior acromioclavicular joint dislocation and an ipsilateral fracture of the middle third of the clavicle in a 17-year-old male is presented. Diagnosis is based on clinical suspicion and imaging test, being CT scan particularly useful. Open reduction and coracoclavicular fixation with excision of the distal clavicle led to successful results. Treatment is compared with previous reports. A review of the literature is made

Ansiedad pre-competitiva y conductas de autocontrol en jugadores de futbol

Partiendo de la conceptualización de la ansiedad dentro de la teoría de rasgo-estado, se estudia la ansiedad precompetitiva de un equipo de fútbol de tercera división. Durante cinco partidos, se aplicó el cuestionario CSAI-2 momentos antes de las competiciones, registrándose la ansiedad cognitiva, somática y autoconfianza precompetitiva de los jugadores. Los partidos se filmaron y posteriormente se estudiaron las conductas no reglamentarias tales como agresiones físicas, protestas al árbitro, protestas a los compañeros de juego, respuestas dadas ante una agresión, tarjetas amarillas, faltas señaladas al jugador y errores garrafales cometidos en el área. De esta forma, se intenta predecir si los jugadores con altas puntuaciones en el cuestionario CSAI-2 mostrarían conductas agresivas durante las competiciones. Los resultados del estudio no muestran correlaciones estadísticamente significativas entre las puntuaciones en CSAI-2 y la aparición de las conductas antideportivas. Finalmente, se discuten diferentes aspectos de la capacidad predictiva del cuestionario de MartensUsing the State-Trait Anxiety Theory, a study about pre competitive anxiety in a 3rd division soccer team players is presented. During five soccer games, the CSAI-2 was individually administrated, a few minutes before starting, and the scores of cognitive, somatic and self-reliance anxiety were taken. All of the soccer games were video taped and then several impartial observers transcribed illicit or/and erroneous sport behaviors during the games: aggression, complains to the referee, serious sport mistakes, penalties, etc. In this analysis we try to assess if the score in a pre competitive anxiety inventory predicts some of these behaviors during the competition. No statistically significant correlation between CSAI-2 scores and sport illicit behaviors were foun

Assessment of the antioxidant properties of tomato extracts: A synergistic approach using in vitro chemical tests and cell-based assays

The aim of this research was to assess the total antioxidant activity (TAA) of lipophilic (Lextr) and hydrophilic (Hextr) tomato extracts using in vitro chemical tests and cell-based assays, focusing on possible synergistic actions between tomato antioxidants. Both Hextr and Lextr were HPLC analysed for their carotenoids, phenolic compounds, and ascorbic acid contents. For the evaluation of TAA, extracts were assayed alone or in combination using in vitro chemical tests (TEAC, FRAP) and cell-based (CAA) assays using human hepatoma (HepG2) and human histiocytic lymphoma (U937) cells. The only carotenoid detected in Lextr was lycopene, while a mixture of phenolic compounds (chlorogenic acid, caffeic acid, and rutin) was identified in Hextr. Ascorbic acid was not found either in Hextr or in Lextr. Upon extract combination (1:1, v/v), the FRAP assay revealed additive action between Lextr and Hextr, whilst a slight synergistic action was observed in TAA as measured by the TEAC assay. Synergistic action was better revealed when TAA was analysed using either U937 or HepG2 cells. This could be explained by the presence of a multiphase media (cell membrane and extra- and intracellular media) that might facilitate the distribution and interaction of antioxidants with different polarities and different mechanisms of action

Website Architecture, Information Flows and Cognitive Models

This paper explores the relation between new digital genres configuration and their users’ previous knowledge patterns from an interlinguistic perspective. More precisely, first we analyse two models that underlie the formal architecture of websites. For that purpose we introduce diverse pieces of software that allow for visualization of website organization in terms of nodes and links. Then, we show the most entrenched metaphoric models that provide cognitive tools for users to understand website configuration and usage, in an English speaking culture. Finally, we discuss to what extent these models can be transferred and learned by users from other cultures, particularly in Spanish speaking communitie

Coastal macrophytes contribute to the long term geomorphological stability of Cadiz Bay

Charla presentada en el 2015 Aquatic Sciences Meeting. Aquatic Sciences: Global And Regional Perspectives — North Meets South (http://sgmeet.com/aslo/granada2015)In the Eastern Gulf of Cadiz, terrestrial sediments are mainly supplied by the large Guadalquivir and smaller Guadalete rivers, both of which are subject to substantial man-made interventions. These rivers are the main sediment source to Cadiz Bay; a shallow, meso-tidal bay with high subtidal macrophyte coverage and extensive salt marshes that appears to act as an effective filter, retaining fine material and ensuring accretion rates that match sea-level rise. Field observations suggest that the relative importance of the different mechanisms by which macrophyte canopies promote accretion is related to their species-specific biometric properties and zonation. Overall, we argue that the key mechanism which enhances long-term accretion in the bay is related to the reduction of erosive forces on the sediment bed cause by the interaction of plant canopies with local hydrodynamics, particularly during high wind events. Considering the importance of coastal macrophytes for long-term accretion, we briefly discuss how different local and regional management strategies in relation to IPCC climate change predictions may influence terrestrial derived-sediment dynamics.EU FP7-SPACE-2013: FAST - GA n.607131, Junta Andalucia: P07-RNM-2516, P09-RNM-4853, PR11-RNM-7722,MECD: CTM2008-00012/MAR, Schure-Beijerinck-Popping Fund: SBP/JK/2007-32), E.U. MarinERA Project MedEX: CTM2008-04036-E/MAR) y PERSEUS (FP7-287600)Charla en formato pd