Purificación, caracterización funcional y estructural de cisteín proteinasas presentes en frutos maduros de Bromelia antíacantha. Evaluación de sus posibles aplicaciones

Las proteasas o peptidasas, son enzimas que catalizan la hidrólisis del enlace peptídico de las proteínas. Se describen cinco clases de acuerdo a su mecanismo catalítico: proteasas aspárticas, de cisteína, metálicas, de serina y de treonina. Estas enzimas desempeñan papeles clave en todos los organismos vivos. A pesar de catalizar la misma reacción, la especificidad por el sustrato suele ser marcadamente diferente para cada proteasa, haciéndolas moléculas únicas. El estudio de nuevas peptidasas, aporta información valiosa permitiendo una mayor comprensión de las propiedades que definen la especificidad y la relación estructura-función, además de generar nuevas herramientas biotecnológicas. En este contexto, se trabajó con frutos maduros de Bromelia antiacantha Bertol., una especie autóctona, perteneciente a la familia Bromeliaceae. Partiendo del extracto de estos frutos y conociendo los puntos isoeléctricos de sus componentes proteicos, se empleó una metodología de purificación simple que permitió separar tres nuevas peptidasas que denominamos: Antiacanthaína A (AntA), Antiacanthaína B (AntB) y Antiacanthaína C (AntC). La caracterización bioquímica de las tres enzimas mostró que ellas tienen propiedades similares y típicas de las cisteín peptidasa

Efectos de la regulación en las condiciones de competencia de Puerto Nuevo de Buenos Aires

En este trabajo se analiza la regulación de Puerto Nuevo de Buenos Aires y sus recientes modificaciones. Los cambios regulatorios introducidos, relajan las restricciones impuestas originalmente en la privatización de las terminales del puerto, permitiendo operaciones de integración horizontal entre las terminales. Asimismo, el marco regulatorio no previó la posibilidad de participación de otros actores del sector en la operación de terminales (integración vertical). El objetivo de este trabajo es analizar cómo estos factores influyen sobre las condiciones de competencia en el sector y establecer recomendaciones sobre puntos a considerar en el futuro.regulación de Puerto Nuevo; privatización de las terminales del puerto; marco regulatorio

Las redes sociales en el aula, beneficios, usos y aplicación en la asignatura de economía

El titulo de este proyecto es “Las redes sociales en el aula, beneficios, usos y aplicación en la asignatura de economía.”, como indica, voy a realizar una investigación sobre los posibles usos de las redes sociales en la asignatura de Economía. Además inicio este trabajo con un resumen de los conocimientos adquiridos en el “Máster en Profesorado de E.S.O., F.P. y Enseñanzas de Idiomas, Artísticas y Deportivas.”A lo largo de este proyecto analizo tres puntos. Primero, los problemas y beneficios que tienen las redes sociales en la comunicación de los jóvenes. En segundo lugar, investigo sobre los usos que ya se están dando en algunos centros educativos. Y por último, propongo unas actividades basadas en el uso de redes sociales para la asignatura de Economía.<br /

Búsqueda de actividad inhibitoria de tripsina y elastasa en extractos de vegetales autóctonos = Search of inhibitory activity of trypsin and elastase in extracts of native plants

Se estudió la capacidad inhibitoria para tripsina y elastasa de extractos de vegetales autóctonos: flores de Achyrocline satureioidehojas (marcela), hojas de Baccharis trimera (carqueja), frutos de Eugenia uniflora (pitanga) y frutos Schinus molle (anacahuita). Los extractos, que presentaron diferentes propiedades, se obtuvieron utilizando agua o etanol como solventes en distintas condiciones de tiempo y temperatura. La acción inhibitoria para elastasa fue baja (< 30%) o casi nula en los extractos ensayados. Para la tripsina, todos los extractos presentaron acción inhibitoria, observándose para un mismo material vegetal importantes diferencias según el solvente utilizado, independientemente de la temperatura de extracción. Los extractos de S. molle fueron los de mayor actividad inhibitoria para tripsina. Al extracto acuoso de este vegetal, obtenido a 100 °C, se le determinó IC50 y tipo de inhibición

Granulosain I, a cysteine protease isolated from ripe fruits of Solanum granuloso-leprosum (Solanaceae)

A new cysteine peptidase (Granulosain I) was isolated from ripe fruits of Solanum granuloso-leprosum Dunal (Solanaceae) by means of precipitation with organic solvent and cation exchange chromatography. The enzyme showed a single band by SDS-PAGE, its molecular mass was 24,746 Da (MALDI-TOF/MS) and its isoelectric point was higher than 9.3. It showed maximum activity (more than 90%) in the pH range 7-8.6. Granulosain I was completely inhibited by E-64 and activated by the addition of cysteine or 2-mercaptoethanol, confirming its cysteinic nature. The kinetic studies carried out with PFLNA as substrate, showed an affinity (Km 0.6 mM) slightly lower than those of other known plant cysteine proteases (papain and bromelain). The N-terminal sequence of granulosain I (DRLPASVDWRGKGVLVLVKNQGQC) exhibited a close homology with other cysteine proteases belonging to the C1A family.Facultad de Ciencias ExactasCentro de Investigación de Proteínas Vegetale

Granulosain I, a cysteine protease isolated from ripe fruits of Solanum granuloso-leprosum (Solanaceae)

A new cysteine peptidase (Granulosain I) was isolated from ripe fruits of Solanum granuloso-leprosum Dunal (Solanaceae) by means of precipitation with organic solvent and cation exchange chromatography. The enzyme showed a single band by SDS-PAGE, its molecular mass was 24,746 Da (MALDI-TOF/MS) and its isoelectric point was higher than 9.3. It showed maximum activity (more than 90%) in the pH range 7-8.6. Granulosain I was completely inhibited by E-64 and activated by the addition of cysteine or 2-mercaptoethanol, confirming its cysteinic nature. The kinetic studies carried out with PFLNA as substrate, showed an affinity (Km 0.6 mM) slightly lower than those of other known plant cysteine proteases (papain and bromelain). The N-terminal sequence of granulosain I (DRLPASVDWRGKGVLVLVKNQGQC) exhibited a close homology with other cysteine proteases belonging to the C1A family.Facultad de Ciencias ExactasCentro de Investigación de Proteínas Vegetale

Biosynthesis of a novel antibacterial dipeptide, using proteases from south american native fruits, useful as a food preservative

Antiacanthain and granulosain are the partially purified proteolytic extracts from the South American native fruits of Bromelia antiacantha (Bertol.) and Solanum granuloso leprosum, respectively. The aim of this work was to compare the ability of both soluble and immobilized antiacanthain and granulosain f or the synthesis of Z-Tyr-Val-OH, a novel antibacterial dipeptide, in different reaction systems formed by almost anhydrous organic solvents (Xw: 1 × 10−5) and several percentages of immiscible organic solvents in 100 mM Tris(hydroxymethyl)aminomethane hydrochloride buffer pH 8.0. Soluble antiacanthain in half of the 24 different organic biphasic media showed higher catalytic potential than in 100 mM Tris(hydroxymethyl)aminomethane hydrolchloride buffer pH 8.0. Soluble granulosain showed lower catalytic potential in all liquid-liquid biphasic media than in the same buffer. However, 50% (v/v) ethyl ethanoate in 100 mM Tris(hydroxymethyl)aminomethane hydrolchloride buffer pH 8.0 allowed to express the highest catalytic potential of both soluble enzymes. In 50% v/v ethyl ethanoate, soluble antiacanthain and granulosain catalyzed the synthesis of Z-Tyr-Val-OH with 72 ± 0.15 and 60 ± 0.10% maximal peptide yields, respectively. Multi-point immobilization in glyoxyl-silica did not lead to better peptide yields than soluble enzymes, in that liquid-liquid biphasic medium under the same reaction conditions. Soluble and glyoxyl-silica immobilized antiacanthain in almost anhydrous ethyl ethanoate (Xw: 1 × 10−5) were able to retain 17.3 and 45% of the initial proteolytic activity of antiacanthain in 100 mM Tris hydrolchloride buffer pH 8.0, respectively, at 40°C under agitation (200 rpm). Soluble and glyoxyl-silica immobilized granulosain were inactivated under the same reaction conditions. Glyoxyl-silica immobilized antiacanthain showed to be a robust biocatalyst in almost anhydrous ethyl ethanoate (Xw: 1 × 10−5), eliciting the best peptide yield (75 ± 0.13%). The synthesis reaction of Z-Tyr-Val-OH could not proceed when soluble antiacanthain was used under the same conditions. Both peptidases only catalyzed the synthesis reaction under kinetic control, using activated acyl donor substrates. Finally, this work reports a novel broad-spectrum antibacterial peptide that significantly decreased (p ≤ 0.05) the specific growth rates of Gram positive and Gram negative microorganisms at very low concentrations (≥15 and 35 μg/ml, respectively); contributing with a new safe food preservative of applying for different food systems.Fil: Adaro, Mauricio Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Farmacia. Laboratorio de Bromatología; ArgentinaFil: Bersi, Grisel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Farmacia. Laboratorio de Bromatología; ArgentinaFil: Talia, Juan Manuel. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bernal, Cintia Claudia. Universidad de La Serena; ChileFil: Guzmán, Fanny. Pontificia Universidad Católica de Valparaíso; ChileFil: Vallés, Diego. Universidad de la República; UruguayFil: Barberis, Sonia Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Farmacia. Laboratorio de Bromatología; Argentin

Channeled polymeric scaffolds with polypeptide gel filling for lengthwise guidance of neural cells

CNS damages are often irreversible since neurons of the central nervous system are unable to regenerate after an injury. As a new strategy within the nervous system tissue engineering, multifunctional systems based on two different biomaterials to support axonal guidance in damaged connective tracts have been developed herein. These systems are composed of a channeled scaffold made of ethyl acrylate and hydroxyethyl acrylate copolymer, P(EA-co-HEA), with parallel tubular micropores, combined with an injectable and in situ gelable self-assembling polypeptide (RAD16-I) as pores filler. The polymer scaffold is intended to provide a three-dimensional context for axon growth; subsequently, its morphology and physicochemical parameters have been determined by scanning electron microscopy, density measurements and compression tests. Besides, the hydrogel acts as a cell-friendly nanoenvironment while it creates a gradient of bioactive molecules (nerve growth factor, NGF) along the scaffolds channels; the chemotactic effect of NGF has been evaluated by a quantitative ELISA assay. These multifunctional systems have shown ability to keep circulating NGF, as well as proper short-term in vitro biological response with glial cells and neural progenitors.The authors acknowledge funding through the Spanish Ministerio de Ciencia e Innovacion (MAT2011-28791-C03-02 and -03). Dr. J.M. Garcia Verdugo (Department of Comparative Neurobiology, Cavanilles Institute of Biodiversity and Evolutive Biology, Universitat de Valencia) is thanked for kindly providing the cells employed in this work.Conejero García, Á.; Vilarino-Feltrer, G.; Martínez Ramos, C.; Monleón Pradas, M.; Vallés Lluch, A. (2015). Channeled polymeric scaffolds with polypeptide gel filling for lengthwise guidance of neural cells. European Polymer Journal. 70:331-341. doi:10.1016/j.eurpolymj.2015.07.033S3313417

Granulosain I, a cysteine protease isolated from ripe fruits of Solanum granuloso-leprosum (Solanaceae)

A new cysteine peptidase (Granulosain I) was isolated from ripe fruits of Solanum granuloso-leprosum Dunal (Solanaceae) by means of precipitation with organic solvent and cation exchange chromatography. The enzyme showed a single band by SDS-PAGE, its molecular mass was 24,746 Da (MALDI-TOF/MS) and its isoelectric point was higher than 9.3. It showed maximum activity (more than 90%) in the pH range 7-8.6. Granulosain I was completely inhibited by E-64 and activated by the addition of cysteine or 2-mercaptoethanol, confirming its cysteinic nature. The kinetic studies carried out with PFLNA as substrate, showed an affinity (Km 0.6 mM) slightly lower than those of other known plant cysteine proteases (papain and bromelain). The N-terminal sequence of granulosain I (DRLPASVDWRGKGVLVLVKNQGQC) exhibited a close homology with other cysteine proteases belonging to the C1A family.Facultad de Ciencias ExactasCentro de Investigación de Proteínas Vegetale

Prediction of the in vivo mechanical behavior of biointegrable acrylic macroporous scaffolds

[EN] This study examines a biocompatible scaffold series of random copolymer networks P(EA-HEA) made of Ethyl Acrylate, EA, and 2-Hydroxyl Ethyl Acrylate, HEA. The P(EA-HEA) scaffolds have been synthesized with varying crosslinking density and filled with a Poly(Vinyl Alcohol), PVA, to mimic the growing cartilaginous tissue during tissue repair. In cartilage regeneration the scaffold needs to have sufficient mechanical properties to sustain the compression in the joint and, at the same time, transmit mechanical signals to the cells for chondrogenic differentiation. Mechanical tests show that the elastic modulus increases with increasing crosslinking density of P(EA-HEA) scaffolds. The water plays an important role in the mechanical behavior of the scaffold, but highly depends on the crosslinking density of the proper polymer. Furthermore, when the scaffold with hydrogel is tested it can be seen that the modulus increases with increasing hydrogel density. Even so, the mechanical properties are inferior than those of the scaffolds with water filling the pores. The hydrogel inside the pores of the scaffolds facilitates the expulsion of water during compression and lowers the mechanical modulus of the scaffold. The P(EA-HEA) with PVA shows to be a good artificial cartilage model with mechanical properties close to native articular cartilage.This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2013-46467-C4-1-R (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The authors acknowledge the assistance and advice of Electron Microscopy Service of the UPV.Vikingsson, L.; Antolinos Turpín, CM.; Gómez-Tejedor, JA.; Gallego Ferrer, G.; Gómez Ribelles, JL. (2016). Prediction of the in vivo mechanical behavior of biointegrable acrylic macroporous scaffolds. Materials Science and Engineering: C. 61:651-658. https://doi.org/10.1016/j.msec.2015.12.068S6516586