A Novel Two-domain Architecture Within the Amino Acid Kinase Enzyme Family Revealed by the Crystal Structure of Escherichia coli Glutamate 5-kinase

Glutamate 5-kinase (G5K) makes the highly unstable product glutamyl 5-phosphate (G5P) in the initial, controlling step of proline/ornithine synthesis, being feedback-inhibited by proline or ornithine, and causing, when defective, clinical hyperammonaemia. We determined two crystal structures of G5K from Escherichia coli, at 2.9 Å and 2.5 Å resolution, complexed with glutamate and sulphate, or with G5P, sulphate and the proline analogue 5-oxoproline. E. coli G5K presents a novel tetrameric (dimer of dimers) architecture. Each subunit contains a 257 residue AAK domain, typical of acylphosphate-forming enzymes, with characteristic α3β8α4 sandwich topology. This domain is responsible for catalysis and proline inhibition, and has a crater on the β sheet C-edge that hosts the active centre and bound 5-oxoproline. Each subunit contains a 93 residue C-terminal PUA domain, typical of RNA-modifying enzymes, which presents the characteristic β5β4 sandwich fold and three α helices. The AAK and PUA domains of one subunit associate non-canonically in the dimer with the same domains of the other subunit, leaving a negatively charged hole between them that hosts two Mg ions in one crystal, in line with the G5K requirement for free Mg. The tetramer, formed by two dimers interacting exclusively through their AAK domains, is flat and elongated, and has in each face, pericentrically, two exposed active centres in alternate subunits. This would permit the close apposition of two active centres of bacterial glutamate-5-phosphate reductase (the next enzyme in the proline/ornithine-synthesising route), supporting the postulated channelling of G5P. The structures clarify substrate binding and catalysis, justify the high glutamate specificity, explain the effects of known point mutations, and support the binding of proline near glutamate. Proline binding may trigger the movement of a loop that encircles glutamate, and which participates in a hydrogen bond network connecting active centres, which is possibly involved in the cooperativity for glutamate. © 2007 Elsevier Ltd. All rights reserved.This work was supported by grants BFU2004-05159, BFU2004-04472 from the Spanish Ministry of Education and Science, and PI052838 from the Spanish Ministry of Health.Peer Reviewe

Association of cholesterol and oxysterols in adipose tissue with obesity and metabolic syndrome traits

Adipose tissue stores a substantial amount of body cholesterol in humans. Obesity is associated with decreased concentrations of serum cholesterol. During weight gain, adipose tissue dysfunction might be one of the causes of metabolic syndrome. The aim of this study is to evaluate cholesterol storage and oxidized metabolites in adipose tissue and their relationship with metabolic clinical characteristics

Complete genome sequence of a novel recombinant Citrus tristeza virus, a resistance-breaking isolate from Uruguay

We report here the complete genome sequence of a Citrus tristeza virus (CTV) from Uruguay, sequenced by using Illumina and Sanger sequencing technology. This CTV DSST-17 genome clustered within genotype resistance breaking (RB) and presents two recombination events

Correction: A feasible pathway to stabilize monoclinic and tetragonal phase coexistence in barium titanate-based ceramics

Depto. de Física de MaterialesFac. de Ciencias FísicasTRUEpu

Emulsiones aceite-en-agua basadas en proteínas de garbanzo

Las emulsiones aceite-en-agua han sido habitualmente estabilizadas usando proteína de huevo. Sin embargo, en los últimos años se ha incrementado considerablemente el uso de proteínas vegetales para reemplazar a las proteínas de origen animal. Esta tendencia es debida a los nuevos hábitos alimentarios de los consumidores, que demandan una mayor presencia de proteínas de origen vegetal. Por otro lado, la incorporación de sustancias bioactivas a estas nuevas emulsiones responde a una línea comercial emergente que tiene como base el concepto de “nutrición saludable”, cuestión en la que se halla cada vez más interesada un mayor número de personas. El trabajo presentado abordó la evaluación del uso de proteína de garbanzo como agente emulsificante para la formulación y optimización de emulsiones de aceiteen- agua. También se evaluó el efecto de la concentración de proteína y el pH de la emulsión sobre la estabilidad de la emulsión. Para ello, se usó harina y concentrado proteico de garbanzo en diferentes concentraciones (2, 4 y 6 % p/p) y se eligieron valores de pH (2,5 y 8) para elaborar las emulsiones (10% aceite, 90% agua). Para favorecer la estabilidad de la emulsión se incorporó goma xantana y, una vez obtenida la pre-emulsión, se finalizó la preparación de las mismas usando un homogeneizador de alta presión. Las emulsiones preparadas se caracterizaron mediante distribución del tamaño de gota, potencial Z, e índice de estabilidad, siendo también evaluadas sus propiedades reológicas. Las mejores propiedades se correspondieron con la emulsión preparada a pH2 con un 4% p/p de concentrado proteico de garbanzo y 0.01% p/p de goma xantana. Los resultados presentados revelan un gran potencial de uso para la elaboración de nuevas emulsiones basadas en legumbres como ingrediente proteico en sustitución de las proteínas de origen animal

Au@p4VP core@shell pH-sensitive nanocomposites suitable for drug entrapment

11 p.-2 schem.-1 graph. abst.We synthesize and characterize pH-responsive hybrid nanocomposites with SERS and drug loading applications. This colloidal system is structured by spherical 50 nm Au cores individually coated by a pH-sensitive shell of poly4-vinylpyridine (Au@p4VP). The synthesis of these hybrid nanocomposites is performed in two steps, a first one involves the fabrication of vinyl-functionalized Au nanoparticles, and a second one includes the controlled overgrowth of a p4VP shell by free radical polymerization. As a result, Au@p4VP hybrid systems with a mean diameter ranging from 150 to 57 nm are obtained upon varying the monomer concentration at synthesis. Au@p4VP nanocomposite exhibits pH-response capabilities, confirmed by cryo-TEM analysis, Small Angle X-ray Scattering (SAXS) and Zeta Potential (ZP) measurements at different pH conditions. The Au@p4VP particles also display a controllable swelling response, which depends on the cross-linker density within the polymer. This swelling capability is analyzed by Dynamic Light Scattering (DLS), and UV–vis spectroscopy at different pHs. The pH-responsive capability is here exploited for the chemical entrapment of doxorubicin hydrochloride (Dox) into the polymer network. The presence of this molecule is resolved by Surface Enhanced Raman Spectroscopy (SERS) measurements. The entrapment efficiency of Dox by the Au@p4VP system is determined via NMR spectroscopy of the supernatants.JCR acknowledges funding from UOC, internal grant N116139473, aimed at enhancing submission to H2020 calls. RCC, JLR and JRR acknowledge financial support from the Spanish MINECO projects CTQ2013-48418P, CTQ2016-76311-R, BFU2016-75319-R and MAT2014-55065R. IF, RCC and ABRM thank the financial support given by Junta de Andalucía (Spain) under the project number P12-FQM-2668. J.F.D acknowledges the networking contributions by the COST actions CM1407 and CM1470.Peer reviewe

Monitorización y seguimiento del esfuerzo realizado por los estudiantes y de su asistencia a actividades presenciales

Este artículo documenta el planteamiento, la metodología y los primeros resultados de un plan de monitorización detallada del esfuerzo y de asistencia a actividades presenciales por parte de los estudiantes de las titulaciones ofertadas por la Escuela Técnica Superior de Ingenieros Navales de la Universidad Politécnica de Madrid durante el segundo cuatrimestre del curso 2011-2012. Se ha establecido un sistema mecánico de recogida de datos de esfuerzo por parte de los estudiantes utilizando una hoja tipo test especialmente configurada al efecto. Se pasa una hoja en todas y cada una de las actividades presenciales realizadas y en la hoja se solicita información sobre el trabajo "fuera de clase". Se documenta en este artículo cómo se ha estructurado esa hoja, qué tipo de datos se recogen, cómo se tratan mediante una base de datos creada al efecto, qué tipo de análisis se puede realizar y qué resultados preliminares obtenemos de dichos análisis

Patrimonio inmaterial en el Ecuador. Una construcción colectiva

Las tradiciones, en contextos de fragilidades geopolíticas, se han visto afectadas por prácticas oculturizantes. Estas, unidas al consumismo y al mercantilismo, pasan, de manera silenciosa, a la trastienda del imperio monocultural. Con la Declaratoria del Patrimonio Inmaterial realizada en la convención de París, en 2003, y ratificada por Ecuador en 2005, se crea una mayor conciencia sobre la importancia de salvaguardar la memoria social y patrimonio colectivo de los pueblos. El presente texto documenta la participación ciudadana en esa tarea de cuidar los saberes y prácticas que son parte de la vida cotidiana de las comunidades, ciudades, pueblos y colectivos; por tanto, parte del patrimonio inmaterial y legado cultural para las presentes y futuras generaciones. Desde la academia, con actores de pueblos, docentes y funcionarios públicos, este libro reflexiona sobre el tema. Frente al inexistente diálogo y pese a la poca documentación existente, este diálogo se convierte en una antesala para la concreación de la Ley Orgánica de Cultura con régimen especial para el patrimonio cultural inmaterial en el Ecuador (2016) y su reglamento (2017). Con esto, la política pública habilita la gestión responsable en torno al cuidado del patrimonio inmaterial en el país

Remdesivir and three other drugs for hospitalised patients with COVID-19: final results of the WHO Solidarity randomised trial and updated meta-analyses.

BACKGROUND World Health Organization expert groups recommended mortality trials of four repurposed antiviral drugs - remdesivir, hydroxychloroquine, lopinavir, and interferon beta-1a - in patients hospitalized with coronavirus disease 2019 (Covid-19). METHODS We randomly assigned inpatients with Covid-19 equally between one of the trial drug regimens that was locally available and open control (up to five options, four active and the local standard of care). The intention-to-treat primary analyses examined in-hospital mortality in the four pairwise comparisons of each trial drug and its control (drug available but patient assigned to the same care without that drug). Rate ratios for death were calculated with stratification according to age and status regarding mechanical ventilation at trial entry. RESULTS At 405 hospitals in 30 countries, 11,330 adults underwent randomization; 2750 were assigned to receive remdesivir, 954 to hydroxychloroquine, 1411 to lopinavir (without interferon), 2063 to interferon (including 651 to interferon plus lopinavir), and 4088 to no trial drug. Adherence was 94 to 96% midway through treatment, with 2 to 6% crossover. In total, 1253 deaths were reported (median day of death, day 8; interquartile range, 4 to 14). The Kaplan-Meier 28-day mortality was 11.8% (39.0% if the patient was already receiving ventilation at randomization and 9.5% otherwise). Death occurred in 301 of 2743 patients receiving remdesivir and in 303 of 2708 receiving its control (rate ratio, 0.95; 95% confidence interval [CI], 0.81 to 1.11; P = 0.50), in 104 of 947 patients receiving hydroxychloroquine and in 84 of 906 receiving its control (rate ratio, 1.19; 95% CI, 0.89 to 1.59; P = 0.23), in 148 of 1399 patients receiving lopinavir and in 146 of 1372 receiving its control (rate ratio, 1.00; 95% CI, 0.79 to 1.25; P = 0.97), and in 243 of 2050 patients receiving interferon and in 216 of 2050 receiving its control (rate ratio, 1.16; 95% CI, 0.96 to 1.39; P = 0.11). No drug definitely reduced mortality, overall or in any subgroup, or reduced initiation of ventilation or hospitalization duration. CONCLUSIONS These remdesivir, hydroxychloroquine, lopinavir, and interferon regimens had little or no effect on hospitalized patients with Covid-19, as indicated by overall mortality, initiation of ventilation, and duration of hospital stay. (Funded by the World Health Organization; ISRCTN Registry number, ISRCTN83971151; ClinicalTrials.gov number, NCT04315948.)