Diverse patterns of molecular changes in the mechano-responsiveness of focal adhesions Malik Sheriff, Rahuman S.; Imtiaz, Sarah; Grecco, Hernan Edgardo; Zamir, Eli Focal adhesions anchor contractile actin fibers with the extracellular matrix, sense the generated tension and respond to it by changing their morphology and composition. Here we ask how this mechanosensing is enabled at the protein-network level, given the modular assembly and multitasking of focal adhesions. To address this, we applied a sensitive 4-color live cell imaging approach, enabling monitoring patterns of molecular changes in single focal adhesions. Co-imaging zyxin, FAK, vinculin and paxillin revealed heterogeneities in their responses to Rho-associated kinase (ROCK)-mediated perturbations of actomyosin contractility. These responses were rather weakly correlated between the proteins, reflecting diverse compositional changes in different focal adhesions. This diversity is partially attributable to the location of focal adhesions, their area, molecular content and previous contractility perturbations, suggesting that integration of multiple local cues shapes differentially focal adhesion mechano-responsiveness. Importantly, the compositional changes upon ROCK perturbations exhibited distinct paths in different focal adhesions. Moreover, the protein exhibiting the strongest response to ROCK perturbations varied among different focal adhesions. The diversity in response patterns is plausibly enabled by the modular mode of focal adhesions assembly and can provide them the needed flexibility to perform multiple tasks by combining optimally a common set of multifunctional components.

Estudio multidisciplinario e interinstitucional de dos fuentes principales de agua potable para la Provincia de Córdoba Bazán, Raquel del Valle; García, Marcelo; Díaz Lozada, José Manuel; Chalimond, María Laura; Herrero, Horacio Sebastian Julian; Bonansea, Matias; Bonfanti, Enzo; Busso, Fanny; Cosavella, Ana Las fuentes de aguas superficiales son eje de desarrollo de los seres humanos, ya que permiten el abastecimiento para diferentes actividades socioeconómicas. No obstante, de forma paradójica, muchas de estas actividades causan alteración y deterioro de las mismas. Con el fin de contribuir al fortalecimiento de la articulación entre el estado, la sociedad y la Universidad desde hace aproximadamente dos décadas un equipo conformado por docentes investigadores, ayudantes de investigación, profesionales y personal técnico realizan un estudio multidisciplinar e interinstitucional en cuerpos de agua superficiales de la provincia de Córdoba. Los mayores esfuerzos están enfocados hacia dos fuentes principales de agua potable de la provincia: El río Tercero (Ctalamochita) -como parte de la cuenca del río Carcarañá- y el embalse Los Molinos. Dado que el agua propicia el bienestar de la población y el crecimiento inclusivo, y tiene un impacto positivo en la vida de las personas, al incidir en aspectos que afectan la seguridad alimentaria y energética, la salud humana y el ambiente; en el presente trabajo se brindan las principales conclusiones y recomendaciones (para diferentes usos) en ambos cuerpos de agua abordando la problemática de calidad y cantidad de agua. Tales recomendaciones aspiran a contribuir al desarrollo de un sistema de gestión integrada de los recursos hídricos con un enfoque participativo para asegurar la sostenibilidad de los ecosistemas involucrados.

A key function for microtubule-associated-protein 6 in activity-dependent stabilisation of actin filaments in dendritic spines Peris, Leticia; Bisbal, Mariano; Martinez Hernandez, José; Saoudi, Yasmina; Jonckheere, Julie; Rolland, Marta; Sebastien, Muriel; Brocard, Jacques; Denarier, Eric; Bosc, Christopher; Guerin, Christophe; Gory Fauré, Sylvie; Deloulme, Jean Christophe; Lanté, Fabien; Arnal, Isabelle; Buisson, Alain; Goldberg, Yves; Blanchoin, Laurent; Delphin, Christian; Andrieux, Annie Emerging evidence indicates that microtubule-associated proteins (MAPs) are implicated in synaptic function; in particular, mice deficient for MAP6 exhibit striking deficits in plasticity and cognition. How MAP6 connects to plasticity mechanisms is unclear. Here, we address the possible role of this protein in dendritic spines. We find that in MAP6-deficient cortical and hippocampal neurons, maintenance of mature spines is impaired, and can be restored by expressing a stretch of the MAP6 sequence called Mc modules. Mc modules directly bind actin filaments and mediate activity-dependent stabilisation of F-actin in dendritic spines, a key event of synaptic plasticity. In vitro, Mc modules enhance actin filament nucleation and promote the formation of stable, highly ordered filament bundles. Activity-induced phosphorylation of MAP6 likely controls its transfer to the spine cytoskeleton. These results provide a molecular explanation for the role of MAP6 in cognition, enlightening the connection between cytoskeletal dysfunction, synaptic impairment and neuropsychiatric illnesses.

Pasado y presente de la noción de resistencia estudiantil: aportes a la investigación y a la enseñanza de sociología de la educación Langer, Eduardo Daniel En este artículo nos proponemos describir las particularidades de la noción de resistencia estudiantil en el pasado y en el presente así como las formas en que esas características contribuyeron, y lo siguen haciendo, para pensar los aportes al campo de producción en investigación así como en la enseñanza de la sociología de la educación.La hipótesis a desarrollar es que junto con las transformaciones en las formaciones históricas y en los dispositivos pedagógicos a través de las reformas educativas, también hay modificaciones en aquello que consideramos resistencia según el contexto, el lugar, los sujetos y las dinámicas que allí se desarrollan. En la actualidad, la resistencia estudiantil ya no conlleva como hace algunas décadas fracaso escolar y social sino las potencialidades, las posibilidades, las formas de insistencia por continuar y sostener la escolaridad. Ello se realiza explorando la noción de resistencia tal como se produjo en el campo investigativo de la sociología de la educación en el pasado y en el presente, recuperando algunas de las transformaciones hacia la actualidad. A la vez, se desarrolla la relación entre la sociología de la educación y los estudios de gubernamentalidad para el estudio de las prácticas de resistencia.; In this article we propose to describe the particularities of the notion of student resistance in the past and in the present as well as the ways in which they contribute to reflect on the field of research and the teaching of the sociology of education. The hypothesis is that along with the transformations of the historical formations and the pedagogical devices produced by educational reforms, the conception of resistance also changes according to the context, the place, the subjects and its social dynamics. Currently, the student resistance no longer represents, as it did a few decades ago, "the reproduction of the cycle of school and social failure" (Rockwell (2006: 6), but it now represents the potentialities, possibilities, and several ways of insistence coming from the people to continue and keep the schooling (Langer, 2017) This phenomenon can be known by exploring the notion of resistance, and through the recovering of some of its transformations coming from the past to the present. This is a task that the research field of the sociology of education already did it and continue to do so. Therefore, in this article, we also discuss the relationship between the sociology of education and the governmentality studies in their usefulness for the study of the practices of student resistance.

Myelodysplastic syndromes in Latin America: State of the art Crisp, Renée; Grillé, Sofía; Belli, Carolina Bárbara; Diaz, Lilian; Undurraga, Soledad; Navarro, Juan; Vidal, Gabriela; Gusmao, Breno; Reyes, Jheremy; Huaman Garaicoa, Fuad; Magalhaes, Silvia; Barroso, Fernando; Ovilla, Roberto; Flores, Gabriela; Choque, Juan; Distéfano, Marcos; Salinas Viedma, Victor; Iastrebner, Marcelo Latin America is a group of countries that covers an area of approximately 19 197 000 km2. In 2016, itspopulation was estimated at more than 639 million. The prevalent languages are Spanish andPortuguese.Myelodysplastic syndromes (MDSs) are a heterogeneous group of myeloid neoplasms characterized byabnormal differentiation and maturation of myeloid cells, bone marrow failure, and genetic instability withenhanced risk of transforming to acute myeloid leukemia.The incidence rates for MDS in Europe and the United States range from 3 to 5 per 100 000 personyearsand increase markedly with age to 20 per 100 000 person-years for those older than age 70 years.Despite the absence of epidemiologic data, Latin America also has an aging population, as with otherdeveloped countries, and an increasing rate of secondary MDS from previous toxic exposure not only asa consequence of treating other malignancies but also as a result of environmental or occupationalfactors. Diagnosis and treatment remain difficult because of the high number of economic andtechnological disparities within and among Latin American countries.

Recurrent intrusive episodes in the Paleozoic metasedimentary upper crust during the Early Carboniferous time: The Veladero granitoid stock and the peraluminous andesite Dahlquist, Juan Andrés; Alasino, Pablo Horacio; Basei, Miguel A.S.; Morales Camera, Matías Martín; Macchioli Grande, Marcos Simón; da Costa Campos Neto, Mario; García Larrecharte, Matías The Veladero hill is a well-exposed upper crustal block located between the basement of Sierra de Umango (Western Sierras Pampeanas), and the Devonian - Carboniferous sedimentary sequence of Precordillera, at western Argentina. The hill is formed by schists, metaluminous granitoids and a subalkaline peraluminous andesite studied in this work. The country rocks are schists with mineralogy typically developed during a thermal event (e.g., cordierite, andalusite, biotite). The magmatic assemblage of the peraluminous andesite consists of K-feldspar + plagioclase + quartz + biotite + cordierite, with zircon, monazite, and oxides as accessory minerals. One representative sample from this rock was analyzed and has contents of SiO2 = 61%, Fe2O3 t + MgO = 9.03, Na2O + K2O = 6.6%, and aluminium saturation index = 1.5, consistent with the mineralogy. A U-Pb zircon Concordia age of 347 ± 4 Ma was acquired by LA-MC-ICP-MS from zircon hosted in the peraluminous andesite, which together with an age of 342 ± 2 Ma recently published for the metaluminous Veladero granitoid stock, indicate that these two ages overlap within error. Combined mineral assemblage and Al-in-hornblende geobarometric data from the Veladero granitoid stock reveal that the granitic magma passed through ∼10 km of continental crust before reaching its final emplacement level. Field evidence indicates that the Veladero granitoid stock was emplaced under dominantly brittle deformation mechanisms and that the peraluminous andesite magma was generated and subsequently intruded into a previously emplaced magma mush close to solidification, making space by the displacement of large blocks of the host granite. Documented mingling relationships between granite and peraluminous andesite also support emplacement while the granite remained partially crystallized so that the time interval between the two was relatively short, probably on the scale of hundreds of thousands of years. We propose that the peraluminous magma was generated during the ascent of the metaluminous Veladero granitoid stock magma and that the most of the zircon crystallized in high middle crust from the Veladero granitoid stock. These zircons were subsequently recycled and incorporated in the peraluminous andesite. Zircons in the Veladero granitoid stock and the peraluminous andesite have indistinguishable morphology and support this interpretation. In situ Hf isotope data were obtained from igneous zircons in the peraluminous andesite and reveal a dominantly continental source (average εHf,t = −8.0, excluding one just positive value). εHf,t and TDM values from zircon in the Veladero granitoid stock and hosted in the peraluminous andesite are indistinguishable, which is consistent with their original crystallization in the Veladero granitoid stock. TDM values mainly range from 1.5 to 1.9 Ga (average = 1.7 Ga) and reveal a continental Gondwana signature. Consistently, detrital zircon ages from schists in which the igneous rocks were emplaced indicate Ordovician depositional ages and original Gondwanan provenance. However, based on previous studies a Devonian depositional age cannot be ruled out.

Psychosine remodels model lipid membranes at neutral pH Zulueta Díaz, Yenisleidy de Las Mercedes; Caby, Sofia; Bongarzone, Ernesto R; Fanani, Maria Laura β-Galactosylsphingosine or psychosine (PSY) is a single chain sphingolipid with a cationic group, which is degraded in the lysosome lumen by β-galactosylceramidase during sphingolipid biosynthesis. A deficiency of this enzyme activity results in Krabbe's disease and PSY accumulation. This favors its escape to extralysosomal spaces, with its pH changing from acidic to neutral. We studied the interaction of PSY with model lipid membranes in neutral conditions, using phospholipid vesicles and monolayers as classical model systems, as well as a complex lipid mixture that mimics the lipid composition of myelin. At pH 7.4, when PSY is mainly neutral, it showed high surface activity, self-organizing into large structures, probably lamellar in nature, with a CMC of 38 ± 3 μM. When integrated into phospholipid membranes, PSY showed preferential partition into disordered phases, shifting phase equilibrium. The presence of PSY reduces the compactness of the membrane, making it more easily compressible. It also induces lipid domain disruption in vesicles composed of the main myelin lipids. The surface electrostatics of lipid membranes was altered by PSY in a complex manner. A shift to positive zeta potential values evidenced its presence in the vesicles. Furthermore, the increase of surface potential and surface water structuring observed may be a consequence of its location at the interface of the positively charged layer. As Krabbe's disease is a demyelinating process, PSY alteration of the membrane phase state, lateral lipid distribution and surface electrostatics appears important to the understanding of myelin destabilization at the supramolecular level.

Role of human Hv1 channels in sperm capacitation and white blood cell respiratory burst established by a designed peptide inhibitor Zhao, Ruiming; Kennedy, Kelleigh; de Blas, Gerardo Andrés; Orta, Gerardo; Pavarotti, Martin Alejandro; Arias, Rodolfo José; de la Vega Beltrán, José Luis; Li, Qufei; Dai, Hui; Perozo, Eduardo; Mayorga, Luis Segundo; Darszon, Alberto; Goldstein, Steve A. N. Using a de novo peptide inhibitor, Corza6 (C6), we demonstrate that the human voltage-gated proton channel (hHv1) is the main pathway for H+ efflux that allows capacitation in sperm and permits sustained reactive oxygen species (ROS) production in white blood cells (WBCs). C6 was identified by a phage-display strategy whereby ∼1 million novel peptides were fabricated on an inhibitor cysteine knot (ICK) scaffold and sorting on purified hHv1 protein. Two C6 peptides bind to each dimeric channel, one on the S3–S4 loop of each voltage sensor domain (VSD). Binding is cooperative with an equilibrium affinity (Kd) of ∼1 nM at −50 mV. As expected for a VSD-directed toxin, C6 inhibits by shifting hHv1 activation to more positive voltages, slowing opening and speeding closure, effects that diminish with membrane depolarization.

Non-redundancy in seed dispersal and germination by native and introduced frugivorous birds: implications of invasive bird impact on native plant communities Martin Albarracin, Valeria Leticia; Nuñez, Martin Andres; Amico, Guillermo Cesar Seed dispersal by vertebrate animals is important for the establishment of many fleshy-fruited plant species. Different frugivorous species can provide different seed dispersal services according to their specific dietary preferences as well as behaviour and body traits (e.g. body size and beak size of birds). Our aim was to study redundancies and complementarities in seed dispersal and germination between the two main native seed disperser birds and the introduced silver pheasant Lophura nycthemera in the temperate Patagonian forests. For this, we collected fresh droppings from the studied species and analyzed seed content. We conducted germination trials for four plant species common in bird droppings; two native species (Aristotelia chilensis and Rhaphithamnus spinosus) and two invasive non-native species (Rubus ulmifolius and Rosa rubiginosa). Both native frugivorous birds and the silver pheasant dispersed fruits of non- native fleshy-fruited plants, but their roles were non-redundant in terms of species dispersed and effect on seed germination. The silver pheasant dispersed a proportionally high number of non-native seeds, while native birds dispersed a high number of native seeds. In addition, the effect of gut treatment in seed germination differed between seed dispersers. Native birds promoted the germination for the two native plant species studied, while the silver pheasant promoted the germination of one non-native plant. This suggests that seed dispersal by the silver pheasant may contribute to the spread of some invasive fleshy-fruited plants in the ecosystems that otherwise would not be dispersed by any other bird. The understanding of redundancies and complementarities on seed dispersal and germination between native and introduced birds will allow improving the management of fleshy-fruited non-native plants.

Municipios y calidad de vida: análisis de la cobertura de servicios básicos en la provincia de Santa Fe entre 2001 y 2010; Municipalities and Quality of Life: An Analysis of Basic Services coverage between 2001 and 2010 in the Province of Santa Fe, Argentina Gomez, Nestor Javier; Carñel, Griselda Elena; Tarabella, Laura Este trabajo analiza la cobertura de servicios domiciliarios básicos en los 55 municipios existentes en la provincia de Santa Fe, Argentina. El avance de estos es un constante desafío y, en general, su mejora es percibida como progreso de la calidad de vida y un factor retroalimentador del desarrollo. En primer lugar, se determinan y contrastan tasas e índices de cobertura de servicios de 2001 y 2010. Luego, se analiza la variación de la cobertura en el período citado a la luz del incremento de los hogares. En un tercer momento, a fin de indagar en algunos factores relacio-nados a la variación diferencial de la cobertura, se analizan los cambios teniendo en cuenta la magnitud poblacional —cohortes— y la pertenencia regional de los municipios. La metodología combina indicadores tocantes a la provisión de servicios domiciliarios considerados básicos para la vida urbana. Las fuentes de información son los Censos Nacionales de Población, Hogares y Viviendas de la República Argentina (INDEC, 2001) (INDEC , 2010), como así también el Instituto Provincial de Estadísticas y Censos de la Provincia de Santa Fe —Argentina— (IPEC, 2017). Los resultados permitieron dimensionar el proceso de cambio cuantitativo y territo-rial de la cobertura de servicios domiciliarios entre 2001 y 2010. Se detectaron asociaciones no-causales entre la cobertura de los servicios básicos considerados y la magnitud demográfica de los municipios, de forma conjunta con su localización en el territorio provincial.; In this paper we will analyse the coverage of basic services in the 55 municipalities of Santa Fe Province. In a broad sense, the growth of this kind of services is a constant challenge; its improvement reflects the progress in the quality of life. It is also an important factor to explain development. In the first place, we will determine and compare rates of the coverage of basic services from 2001 to 2010. In order to do so, we will analyse the coverage variation of that period taking into account housing increment. In the third place, we will examine changes considering population size—cohorts—and the regional belonging of the municipalities, seeking to understand the related factors to coverage variation along the aforementioned period, Regarding the methodological approach, we will combine different relevant rates of the provision of basic home services for urban life. Our information sources are the Censos Nacionales de Población, Hogares y Viviendasde Argentina (INDEC, 2001) (INDEC , 2010), and also statistics of the Instituto Provincial de Estadísticas y Censos de la Provincia de Santa Fe -Argentina- (IPEC, 2017). The achievements gave us the opportunity to appreciate the quan-titative change process of the coverage of basic services in the area between the years 2001 and 2010. We have detected non-causal connections between the coverage of basic services and municipalities’ demographic size with its location in the province.

Experimental and computational studies of the effects of free DHA on a model phosphatidylcholine membrane Verde, Alejandro Raúl; Sierra, Maria Belen; Alarcon, Laureano Martin; Pedroni, Viviana Isabel; Appignanesi, Gustavo Adrian; Morini, Marcela Ana Docosahexaenoic acid (DHA, 22:6) is a natural active compound that has raised considerable interest due to its several biological effects. In this work, effects of free DHA on the physicochemical properties of dipalmitoylphosphatidylcholine (DPPC) liposomes are investigated in terms of lipid membrane structure, by means of temperature-dependent zeta potential measurements, density studies and molecular dynamics simulations. Experimental results predict, in good agreement with simulations that DHA readily incorporates into DPPC liposomes, localizing at the lipid headgroup region. These data show that DHA induces changes in the lipid bilayer structure as well as in membrane fluidity.

Characterization of non-target-site mechanisms in imidazolinone-resistant sunflower by RNA-seq; Caracterización de mecanismos de resistencia no relacionados al sitio de acción en girasol mediante RNA-seq Gil, Mercedes; Vega Tessandori, María Fernanda; Felitti, Silvina Andrea; Picardi, Liliana Amelia; Balzergue, Sandrine; Nestares, Graciela María Los girasoles Imisun son cultivares resistentes a imidazolinonas en los cuales coexisten dos mecanismos de resistencia: (i) una mutación puntual en el sitio blanco del herbicida (resistencia relacionada al sitio de acción) y (ii) resistencia no relacionada al sitio de acción (NTSR). En la tecnología Imisun, NTSR podría estar relacionada con el metabolismo del herbicida y podría resultar de una sobreexpresión constitutiva de los genes detoxificadores, o inducida luego del tratamiento con herbicida. El objetivo de este trabajo fue caracterizar NTSR en girasoles Imisun en respuesta al tratamiento de imazetapir mediante RNA-seq, y determinar si estos mecanismos son constitutivo o inducidos por el herbicida. Las cipselas fueron germinadas en multimacetas, regadas por capilaridad y se mantuvieron en una cámara bajo condiciones controladas. Plantas de 7 días fueron tratadas con imazetapir 0 (control) y 1 μM por 12 h. Luego de la purificación del RNA de hoja, se construyeron bibliotecas de cDNA stranded y paired-end. La secuenciación se llevó a cabo en Illumina HiSeq2000. Se realizaron dos tipos de estrategias de mapeo local contra el transcriptoma de referencia HaT13l, incluyendo y filtrando multihits, respectivamente y se realizó el análisis de la expresión diferencial. Se identificaron 61 y 47 contigs (de acuerdo a la estrategia de mapeo) relacionados a metabolismo de xenobióticos: citocromos P450, transportadores ABC, glicosiltransferasas, UDPglucuronosil/glucosiltransferasas y glutatión S-transferasas. No se encontró expresión diferencial entre las plantas tratadas y sin tratar con imazetapir para ninguno de los contigs. La expresión de 17 contigs de interés fue validada mediante qRT-PCR. Estos resultados sugieren que mecanismos NTSR constitutivos estarían involucrados con la resistencia a imidazolinonas en girasol.; Imisun sunflowers (Helianthus annuus L.) are imidazolinone-resistant cultivars in which the two mechanisms of herbicide resistance coexist: (i) mutation in herbicide target-site (target-site resistance) and (ii) non-target-site resistance (NTSR). In Imisun technology, NTSR could be related to herbicide metabolism and might occur as a result of a constitutive up-regulation of resistance genes, or it can appear only after herbicide treatment. The objective of this study was to characterize NTSR in Imisun sunflower in response to imazethapyr using RNA-Seq and to determine whether these mechanisms are constitutive or herbicide-induced. Cypsels were germinated in plastic pots, watered by capillarity and growth in chamber under controlled conditions. Seven-day-old plants were treated with 0 (control) and 1 μM imazethapyr for 12 h. After leaf RNA purification, stranded, paired-end cDNA libraries were constructed. Sequencing was performed with Illumina HiSeq2000. Local mapping, with and without multihits, was carried out over the reference transcriptome HaT13l and differential expression was analysed. Sixty one and 47 contigs (according to mapping strategy) related to xenobiotic metabolism were found: cytochromes P450s, ABC transporters, glycosyltransferases, UDPglucuronosyl/glucosyltransferases and glutathione S-transferases. None of these contigs showed differential expression between control and imazethapyr-treated plants. Seventeen interesting contigs were verified by qRT-PCR. These results suggest that constitutive NTSR mechanisms may account for imidazolinone resistance in Imisun sunflower.

Trichinella spiralis in a South American sea lion (Otaria flavescens) from Patagonia, Argentina Pasqualetti, Mariana Ines; Fariña, Fernando Adrián; Krivokapich, Silvio Jesús; Gatti, G. M.; Daneri, Gustavo Adolfo; Varela, Esperanza Amalia; Lucero, Sergio; Ercole, Mariano Emmanuel; Bessi, Clara; Winter, Marina; Ribicich, Miriam Mabel Trichinella spp. from a sylvatic cycle has been found in several animal species such as pumas (Puma concolor), armadillos (Chaetophractus villosus), rats (Rattus norvegicus), and wild boars (Sus scrofa) in Argentina. Moreover, Trichinella infection has been detected in a wide range of marine mammals around the world, including polar bears (Ursus maritimus) and walruses (Odobenus rosmarus). Until the present time, Trichinella spp. infection has not been detected in marine mammals of South America. Samples from four South American sea lions (Otaria flavescens) found dead in Rio Negro, Argentina, were analyzed by artificial digestion, and in the case of one animal, Trichinella larvae were identified at the species level by nested multiplex PCR as Trichinella spiralis. This is the first report of a Trichinella species infecting marine mammals from South America.

Development and Validation of a Novel HPLC Method for the Analysis and Quantification of Dehydroleucodine in Plant Extracts Mariani, María Laura Lucía; Penissi, Alicia Beatriz Background: Dehydroleucodine is a sesquiterpene lactone isolated from Artemisia douglasiana Besser. Distinctive biological and pharmacological activities have been shown extensively for this molecule. Only one analytical method has been described for the quantification of dehydroleucodine in biological experimental systems. However, this assay involves fluorescent detection that is normally not recommended for routine analysis. Objective: The goal of this study was to develop and validate a novel methodology for rapid detection and quantitation of dehydroleucodine by HPLC with UV detection. Method: The method involved the use of a C18 separation column, an acetonitrile/water (80:20, v/v) solution as a mobile phase in an isocratic mode at a flow rate of 1 ml/min, and UV detection at 254 nm. Results: In the selected experimental conditions, dehydroleucodine exhibited a well-defined chromatographic peak with a retention time of 3.51 min. The chromatographic signal shows a linear dependence with the dehydroleucodine concentration. Correlation coefficient: 0.99. LOD: 1.5 ng/mL. LOQ: 15 ng/mL. Conclusion: The current method is simpler, faster, and cheaper than the previously reported one, and besides it could be useful to quantify this lactone and related pharmacological compounds. Furthermore, quality control of medicinal extracts of plant origin could be analyzed, and the concentration of the active constituent could be certified by this method.

Androgens downregulate anti-Müllerian hormone promoter activity in the Sertoli cell through the androgen receptor and intact steroidogenic factor 1 sites Edelsztein, Nadia Yasmín; Racine, Chrystèle; di Clemente, Nathalie; Schteingart, Helena Fedora; Rey, Rodolfo Alberto Testicular anti-Müllerian hormone (AMH) production is inhibited by androgens around pubertal onset, as observed under normal physiological conditions and in patients with precocious puberty. In agreement, AMH downregulation is absent in patients with androgen insensitivity. The molecular mechanisms underlying the negative regulation of AMH by androgens remain unknown. Our aim was to elucidate the mechanisms through which androgens downregulate AMH expression in the testis. A direct negative effect of androgens on the transcriptional activity of the AMH promoter was found using luciferase reporter assays in the mouse prepubertal Sertoli cell line SMAT1. A strong inhibition of AMH promoter activity was seen in the presence of both testosterone and DHT and of the androgen receptor. By site-directed mutagenesis and chromatin immunoprecipitation assays, we showed that androgen-mediated inhibition involved the binding sites for steroidogenic factor 1 (SF1) present in the proximal promoter of the AMH gene. In this study, we describe for the first time the mechanism behind AMH inhibition by androgens, as seen in physiological and pathological conditions in males. Inhibition of AMH promoter activity by androgens could be due to protein-protein interactions between the ligand-bound androgen receptor and SF1 or by blockage of SF1 binding to its sites on the AMH promoter.

Widespread but heterogeneous responses of Andean forests to climate change Fadrique, Belén; Báez, Selene; Duque, Álvaro; Malizia, Agustina; Blundo, Cecilia Mabel; Carilla, Julieta; Osinaga Acosta, Oriana; Malizia, Lucio Ricardo; Silman, Miles; Farfán Ríos, William; Malhi, Yadvinder; Young, Kenneth R.; Cuesta C., Francisco; Homeier, Jurgen; Peralvo, Manuel; Pinto, Esteban; Jadan, Oswaldo; Aguirre, Nikolay; Aguirre, Zhofre; Feeley, Kenneth J. Global warming is forcing many species to shift their distributions upward, causing consequent changes in the compositions of species that occur at specific locations. This prediction remains largely untested for tropical trees. Here we show, using a database of nearly 200 Andean forest plot inventories spread across more than 33.5° latitude (from 26.8° S to 7.1° N) and 3,000-m elevation (from 360 to 3,360 m above sea level), that tropical and subtropical tree communities are experiencing directional shifts in composition towards having greater relative abundances of species from lower, warmer elevations. Although this phenomenon of ‘thermophilization’ is widespread throughout the Andes, the rates of compositional change are not uniform across elevations. The observed heterogeneity in thermophilization rates is probably because of different warming rates and/or the presence of specialized tree communities at ecotones (that is, at the transitions between distinct habitats, such as at the timberline or at the base of the cloud forest). Understanding the factors that determine the directions and rates of compositional changes will enable us to better predict, and potentially mitigate, the effects of climate change on tropical forests.

La Filosofía dentro del contexto de la política científica actual en Argentina Mie, Fabian Gustavo La supervivencia académica de la filosofía está sometida actualmente en Argentina a una presión impuesta por criterios de productividad e impacto alentados a través del rediseño en curso del sistema científico. Si bien este proceso en desarrollo creciente atañe a las ciencias básicas en general, puede advertirse que aspectos específicos de la elaboración del conocimiento filosófico, incluyendo sus períodos de tiempo y criterios de validación tradicionales, son difícilmente compatibles con una idea de conocimiento socialmente dominante cada vez más orientada a la aplicación y al retorno económico de la inversión en ciencia. En este contexto, es dudoso que la filosofía pueda apelar a justificaciones como la de la ?potencial utilidad?, que tienen a su alcance otras ciencias básicas (Schwarz 2017). Hay dos cuestiones candentes y conjuntas que considerar aquí: (a) ¿qué hace de la filosofía todavía hoy una forma del saber socialmente aceptable?, y (b) ¿por qué el estado tiene que seguir manteniendo con fondos públicos esa disciplina dentro de las instituciones académicas? En este artículo me propongo esbozar una justificación posible del papel que puede caberle a la filosofía en el contexto actual (primeramente enfocado en Argentina); sugiero que esa justificación proviene de la necesidad de revisar críticamente la idea dominante del saber y apunta a reformular el proyecto del ideal humano de racionalidad.

El Jano socialista. Juan B. Justo y el lugar de los símbolos en la política moderna Reyes, Francisco Jerónimo El artículo analiza la forma en que, a lo largo de su carrera política, un dirigente clave del socialismo argentino, Juan B. Justo, concibió el lugar singular que debían ocupar distintas manifestaciones de un fenómeno significativo de la política: los símbolos. A partir de sus experiencias locales y de su conocimiento de otras realidades del mundo occidental, se argumenta que sus valoraciones y propuestas en torno a dicho problema resultaron siempre atadas a cambiantes coyunturas particulares, evidenciando un carácter oscilante y demostrando el peso de las dos fuentes de su pensamiento y acción: una cultura científica ampliamente extendida y la cultura política del socialismo de la Segunda Internacional en que abrevara. El corpus documental se compone de un amplio conjunto de intervenciones de este intelectual-militante (artículos periodísticos y conferencias a cargo del Partido Socialista, así folletos y libros que condensan sus principales aportes doctrinarios), para luego cotejarse con el aporte de otras voces provenientes del socialismo argentino que tensionan los postulados de dicha cultura política sobre el lugar de los símbolos en la modernidad, en general, y en la política argentina de inicios del siglo XX, en particular, en donde el fenómeno nacionalista ocupa un lugar ineludible.

Desfiguración y redención de la naturaleza Grossi, Bruno La ligazón entre narración y experiencia, o como la progresiva desaparición de una causa el empobrecimiento de la otra, es el diagnostico que, aun con sus matices, Lukács y Benjamin afirman a comienzos de los años 30. La crítica a la «descripción» o la «novela pura» (en suma, la autonomía del arte) en ambos autores, supone la pérdida, la separación con aquella inmediatez que ligaba la ficción con la vida. Lo que parece discutirse es siempre el lugar, la relación, el dialogo polémico que el arte establece con la naturaleza. Nuestra lectura intenta reponer el contexto de la discusión y replantear ciertos supuestos que operan en la escritura de ambos filósofos.

Corrosion protection of AZ91D magnesium alloy by a cerium-molybdenum coating. The effect of citric acid as an additive Lehr, Ivana Leticia; Saidman, Silvana Beatriz In order to improve the corrosion resistance of AZ91D magnesium alloy, a coating was formed by a potentiostatic technique from a solutions containing Ce(NO3)3, Na2MoO4 and citric acid (H3Cit). The degree of corrosion protection achieved was evaluated in simulated physiological solution by monitoring the open circuit potential, polarization techniques and electrochemical impedance spectroscopy (EIS). Surface analysis techniques (SEM, EDS, X-ray diffraction and X-ray photoelectron spectroscopy (XPS)) were used for coating characterization. The film is mainly composed by cerium and molybdenum oxides and magnesium oxides and hydroxides. The obtained results show that the corrosion resistance of the coated electrodes has been increased significantly. This improvement in the anticorrosive performance is in part due to the corrosion inhibition properties of H3Cit.