A comparative study of the effect of multiple immersions on Aedini (Diptera: Culicidae) mosquito eggs with emphasis on sylvan vectors of yellow fever virus Alencar, Jerónimo; Gleiser, Raquel M.; Morone, Fernanda; Mello, Cecília Ferreira de; Silva, Júlia dos Santos; Serra Freire, Nicolau Maués; Guimarães, Anthony Érico The effect of multiple immersions on Haemagogus janthinomys, Haemagogus leucocelaenus, Aedes albopictus and Ochlerotatus terrens eggs was studied. Eggs were collected in April, June, October and December of 2011 in Minas Gerais, Brazil. Most of the Aedes and Ochlerotatus eggs hatched upon the first immersion, while Haemagogus eggs showed a varied instalment hatching response. The number of immersions required for hatching increased for eggs collected closer to the dry winter season.

Quaternary evolution of the Cordillera Frontal piedmont between c. 33° and 34°S Mendoza, Argentina Zárate, Marcelo Arístides; Mehl, Adriana Ester; Perucca, Laura Patricia A. The piedmont of Cordillera Frontal between c. 33° and 34°S (Mendoza, Argentina) is a highly populated area deeply modified by human activities, known as Valle de Uco. It is situated within the borderland region of the geological provinces of Cordillera Frontal and Cuyo basin. The landscape is dominantly composed of both erosional and depositional landforms made of fluvio-aeolian deposits fractured and folded by tectonic processes together with some landforms of volcanic origin. Alluvial fans, related to several aggradational cycles of Quaternary age, are the most remarkable geomorphological units. Several tectonic features are present giving rise to conspicuous morphological features. Some of the streams are structurally controlled by faults while several drainage anomalies that indicate active tectonic processes have been identified. The Late Quaternary alluvial sequences, dominantly comprising sandy and silty deposits of volcaniclastic composition and secondarily metamorphic rocks, represent the fine-grained sedimentary facies of the fluvial systems accumulated in a distal fan environment. The alluvial deposits have been incised by several episodes of erosion since Pleistocene time. The Andes Cordillera and the piedmont of Mendoza province (Argentina) are an active tectonic area characterized by a complex geological setting that determines a heterogeneous landscape. Of particular environmental and human significance is the piedmont of Cordillera Frontal between c. 33° and 34°S. Known as Valle de Uco, it is a highly populated area deeply modified by human activities and constitutes one of the three man-made agricultural oases of Mendoza province (Fig. 1). Consequently, the reconstruction of the piedmont evolution and the understanding of the processes involved are essential to evaluate possible environmental responses under the present climatic fluctuations in a densely populated area. Several contributions have demonstrated the environmental sensitivity of the region during Quaternary time as documented by the record of Pleistocene and Holocene glacial advances in the Andean headwaters of the fluvial systems (e.g. Espizúa 2004, 2005; Espizúa & Pitte 2009; Messager 2010) along with geomorphological, palaeoenvironmental and palaeoclimatic studies (Baker et al. 2009; Paez et al. 2010). In order to understand the nature and characteristics of the present landscape, analysis of the Late Pleistocene and Holocene period is especially important. This key time interval covering the recent geological past includes a dramatic climatic change: the transition of the last glacial cycle to the present interglacial (Saltzman 2002). In addition, the Cordillera Frontal piedmont is considered as one of the source areas of the aeolian deposits of central Argentina (Zárate 2003; Mehl et al. 2012). Knowledge of the sedimentary record is therefore significant to validate the current models of aeolian sedimentation. These issues have renewed interest in the area and instigated multidisciplinary analysis by our research team. The studies, still under progress, include stratigraphical, sedimentological, geochronogical, morphostructural and palaeontological analysis, with the general aim of reconstructing the environmental and climatic conditions during Late Quaternary time across the Cordillera Frontal piedmont (e.g. Mehl & Zárate 2012; Rojo et al. 2012) and the eastern piedmont of San Rafael block, situated to the south (Tripaldi et al. 2011). Simultaneously, other authors (e.g. Pepin 2010; Pepin et al. 2013; Casa et al. 2011) have focused on tectonic, geomorphological and geochronological analyses in the study area (e.g. Cordón del Carrizalito piedmont, Las Tunas fluvial system). The purpose of this paper is to provide a general overview of the Quaternary stratigraphy and evolution of the Cordillera Frontal piedmont at Valle de Uco. Special emphasis is placed on Late Pleistocene and Holocene alluvial sequences that exhibit a suitable stratigraphic resolution for palaeoenvironmental reconstructions. The chronology and morphotectonic of the area are also analysed, along with the composition and provenance of the sediments. The final aim is to contribute to the understanding of the landscape dynamics in an active tectonic setting within the context of the Quaternary climate cycles.

Improved pan-specific MHC class I peptide binding predictions using a novel representation of the MHC binding cleft environment Carrasco Pro, Sebastián; Zimic, Mirko; Nielsen, Morten Major histocompatibility complex (MHC) molecules play a key role in cell-mediated immune responses presenting bounded peptides for recognition by the immune system cells. Several in silico methods have been developed to predict the binding affinity of a given peptide to a specific MHC molecule. One of the current state-of-the-art methods for MHC class I is NetMHCpan, which has a core ingredient for the representation of the MHC class I molecule using a pseudo-sequence representation of the binding cleft amino acid environment. New and large MHC–peptide-binding data sets are constantly being made available, and also new structures of MHC class I molecules with a bound peptide have been published. In order to test if the NetMHCpan method can be improved by integrating this novel information, we created new pseudo-sequence definitions for the MHC-binding cleft environment from sequence and structural analyses of different MHC data sets including human leukocyte antigen (HLA), non-human primates (chimpanzee, macaque and gorilla) and other animal alleles (cattle, mouse and swine). From these constructs, we showed that by focusing on MHC sequence positions found to be polymorphic across the MHC molecules used to train the method, the NetMHCpan method achieved a significant increase in the predictive performance, in particular, of non-human MHCs. This study hence showed that an improved performance of MHC-binding methods can be achieved not only by the accumulation of more MHC–peptide-binding data but also by a refined definition of the MHC-binding environment including information from non-human species.

Cationic porphyrin derivatives for application in photodynamic therapy of cancer Prack Mc Cormick, Bárbara Patricia; Pansa, Maria Florencia; Milla Sanabria, Laura Natalia; Carvalho, Carla Marisa Brito; Faustino, Maria Amparo Ferreira; Neves, Maria Graça P. M. S.; Cavaleiro, José A. S.; Vittar, Natalia Belen Rumie; Rivarola, Viviana Current studies in photodynamic therapy (PDT) against cancer are focused on the development of new photosensitizers (PSs), with higher phototoxic action. The aim of this study was to compare the therapeutic efficiency of tri-cationic meso-substituted porphyrin derivatives (Tri-Py+–Me–PF, Tri-Py+–Me–Ph, Tri-Py+–Me–CO2Me and Tri-Py+–Me–CO2H) with the well-known tetra-cationic T4PM. The phototoxic action of these derivatives was assessed in human colon adenocarcinoma cells by cell viability, intracellular localization and nuclear morphology analysis. In the experimental conditions used we determined that after light activation –PF, –Ph and –CO2Me cause a more significant decline of cell viability compared to –CO2H and T4PM. These results suggest that the nature of the peripheral substituent influences the extent of cell photodamage. Moreover, we have demonstrated that PS concentration, physicochemical properties and further light activation determine the PDT response. All porphyrins were clearly localized as a punctuated pattern in the cytoplasm of the cells, and the PDT scheme resulted in apoptotic cell death after 3 h post-PDT. The tri-cationic porphyrin derivatives Tri-Py+–Me–PF, Tri-Py+–Me–Ph and Tri-Py+–Me–CO2Me showed a promising ability, making them good photosensitizer candidates for oncological PDT.

INQ-1, a chromosome-encoded AmpC β-lactamase from Inquilinus limosus Pino, Marylú; Power, Pablo; Gutkind, Gabriel Osvaldo; Di Conza, José Alejandro

Inmuno-spin trapping from biochemistry to medicine: advances, challenges, and pitfalls. Focus on protein-centered radicals Gomez Mejiba, Sandra E.; Zhai, Zili; Della Vedova, Maria Cecilia; Muñoz, Marcos David; Chatterjee, Saurabh; Towner, Rheal A.; Hensley, Kenneth; Floyd, Robert A.; Mason, Ronald P.; Ramirez, Dario Background: Immuno-spin trapping (IST) is based on the reaction of a spin trap with a free radical to form a stable nitrone adduct, followed by the use of antibodies, rather than traditional electron paramagnetic resonance spectroscopy, to detect the nitrone adduct. IST has been successfully applied to mechanistic in vitro studies, and recently, macromolecule-centered radicals have been detected in models of drug-induced agranulocytosis, hepatotoxicity, cardiotoxicity, and ischemia/reperfusion, as well as in models of neurological, metabolic and immunological diseases. Scope of the review: To critically evaluate advances, challenges, and pitfalls as well as the scientific opportunities of IST as applied to the study of protein-centered free radicals generated in stressed organelles, cells, tissues and animal models of disease and exposure. Major conclusions: Because the spin trap has to be present at high enough concentrations in the microenvironment where the radical is formed, the possible effects of the spin trap on gene expression, metabolism and cell physiology have to be considered in the use of IST and in the interpretation of results. These factors have not yet been thoroughly dealt with in the literature. General significance: The identification of radicalized proteins during cell/tissue response to stressors will help define their role in the complex cellular response to stressors and pathogenesis; however, the fidelity of spin trapping/immuno-detection and the effects of the spin trap on the biological system should be considered.

Estructuras sedimentarias inducidas por actividad microbiana (ESIAM) en la planicie de marea de Puerto Rosales, estuario de Bahía Blanca; Microbially-induced sedimentary structures (MISS) in the Puerto Rosales tidal flat, Bahía Blanca estuary Bournod, Constanza Naimé; Cuadrado, Diana G.; Carmona, Noelia Beatriz; Ponce, Juan Jose; Pan, Jeronimo El estudio de matas microbianas en ambientes marinos costeros silicoclásticos actuales constituye una importante fuente de información para el análisis de análogos fósiles. En el estuario de Bahía Blanca se estudiaron planicies de marea cubiertas por matas desde un enfoque geobiológico, con el objetivo de identificar y describir estructuras inducidas por actividad microbiana (ESIAM), y distinguir rasgos presentes en los sistemas actuales que permitan reconocer estas comunidades de microorganismos en depósitos fósiles. Se realizaron muestreos biológicos y sedimentológicos, y se implementaron técnicas de microscopía óptica y electrónica para la determinación de microorganismos y la identificación de texturas características y minerales autigénicos. Las matas microbianas resultaron estar dominadas por cianobacterias y, en menor proporción, diatomeas; microorganismos que generan sustancias exopoliméricas que bioestabilizan la superficie sedimentaria. Se reconocieron texturas típicas de matas epibentónicas, tales como granos orientados y granos pequeños unidos por la mata, pirita framboidal y ceolitas. En la zona intermareal-supramareal se identificaron domos de gas, fábrica porosa esponjosa y superficies tipo colador. Además se observaron grietas de contracción, dobleces, fragmentos de mata, depresiones y remanentes erosivos, pliegues y arrugas, así como también ondulitas multidireccionales. Las estructuras halladas están relacionadas con condiciones de calma/latencia, exposición prolongada (desecación) y eventos de tormenta con alta energía erosiva sobre la planicie (olas y corrientes fuertes). En este sentido, las ESIAM resultan importantes indicadoras de condiciones ambientales particulares que presentan un elevado potencial de preservación. Su reconocimiento en el registro fósil, a través de rasgos macro y microscópicos, permiten refinar las interpretaciones paleoambientales en sucesiones marino-costeras.; The study of microbial mats in modern siliciclastic coastal marine settings represents an important analogue for the analysis of fossil deposits in similar paleoenvironments. In the Bahía Blanca estuary, mat-covered tidal flats were studied from a geobiological perspective with the aims of identifying and describing microbially-induced sedimentary structures (MISS), and to distinguish features in modern systems that allow the recognition of such microbial communities in fossil deposits. Systematic biological and sedimentological samplings were carried out, and the identification of microorganisms and the recognition and characterization of typical textures and authigenic minerals were performed through light and electronic microscopy techniques. Microbial mats were dominated by cyanobateria, followed by diatoms; both groups of microorganisms are known to secrete extracellular polymeric substances (EPS) and biostabilize the sedimentary surface. Characteristic textures of epibenthic mats, such as oriented grains and mat-bound small grains, framboidal pyrite and zeolites were recognized. In the intertidal-supratidal zone, MISS termed gas domes, sponge pore fabric, and sieve-like surfaces were identified. Moreover, shrinkage cracks, flip-overs, mat chips, erosional remnants and pockets, folds, as well as multidirected ripple marks were observed. These structures are related to calm conditions/latencies, prolonged subaerial exposure (desiccation), and storm events with high hydrodynamic energy (erosive) acting over the tidal flat (e.g. waves and currents). In this sense, MISS constitute important indicators of specific environmental conditions and thus their recognition in the rock record allows a refined interpretation of the paleoenvironment in coastal marine successions.

Adaptación biológica y valor de verdad en creencias cognitivas y morales Zavadivker, María Natalia La perspectiva evolucionista parte del supuesto general de que cualquier rasgo fenotípico (fisiológico, morfológico, conductual, perceptual, cognitivo, etc.) presente en el bagaje genético de la mayoría de los miembros de una población, puede ser tomado como una adaptación biológica a un determinado entorno y a determinadas presiones selectivas. Vale decir, “está allí” como resultado de un proceso de selección natural, por haber contribuido (más eficazmente que otras variantes disponibles en el pasado ancestral) al desempeño exitoso del organismo portador, en términos de supervivencia y éxito reproductivo. A dicho enfoque filogenético, que aportaría las razones evolutivas del bagaje genético con el que vienen equipados los organismos antes de interactuar con el ambiente; habría que sumarle además la perspectiva ontogenética, que daría cuenta del aprendizaje por ensayo y error que cada organismo realiza en interacción directa con el entorno, a lo largo de su desarrollo (tema del que se ocupa, por ejemplo, la Ecología del comportamiento).

Molecular Identification of Brucella Abortus Bv5 and Strain 19 in Water Buffaloes (Bubalus Bubalis) in Northeast Argentina Martinez, Diana; Thompson, Carolina; Russo, Ana Maria; Jacobo, Roberto; Torioni de Echaide, Susana Buffalo (Bubalus bubalis) populations are spread across northern Argentina, and they share their habitat with bovines. Both species are susceptible to brucellosis, and they are under a National Plan of Control and Eradication. To characterize the Brucella spp. that infects buffaloes, the blood of 35 animals that tested positive to brucellosis by a complement fixation test was collected. DNA was obtained and analyzed by polymerase chain reaction using different molecular markers. The genera, species, and biovars of Brucella were established by analyzing specific regions of the genes omp31, eri, alkB, and omp2ab. Brucella spp. was identified in 15 of 35 tested buffaloes. The product of the omp31 gene identified the genera. The detection of two fragments of 297 bp and/or 1000 bp from the eri gene confirmed the presence of B. abortus S19 and wild-type B. abortus. The amplification of the alkB gene allowed the identification of B. abortus biovars characterized by fragments of 498 bp (bv1, bv2, or bv4). The simultaneous amplification of 498 bp (alkB) and 1000 bp (eri) products suggested the presence of B. abortus bv1, which is highly prevalent in the cattle of Argentina. Fragments of 827 bp and 857 bp were amplified from the omp2ab gene, and their sequences showed 100% identity with B. melitensis and B. abortus bv5 (GenBank). However, the 721 bp product (alkB) specific for B. melitensis could not be amplified. This is the first report indicating the presence of B. abortus bv5 in Latin America.

El mito de la viajera en la poesía de Alejandra Pizarnik Calafell Sala, Núria En una poética en la que se anuncia la pérdida del sujeto como representación del yo y la problemática de un lenguaje no constitutivo, el motivo de la viajera se convierte en un símbolo a través del cual expresar el proceso de abandono que la voz poética sufrirá con respecto a sí misma y a su entorno. Esto explicaría las múltiples formas de enmascaramiento con las que Alejandra Pizarnik juega a enmascarar al sujeto de una parte importante de sus poesías: desde la figura de la exiliada, aquella que se sabe expulsada de su propio ser y del mundo aparentemente real, hasta la que inicia un peregrinaje por dos espacios que la sitúan en un ?entre?, todas estas formas se constituyen no sólo en máscaras del yo sino también en significantes con un significado propio.; In a poetic in which is announced the lost of the subject as a representation of the self and the problems of a language that is not constitutive, the topic of the traveller becomes one of the most important symbols to express the process of abandonment that the poetic voice will experience with itself and with the others. That would explain many of the masks that Alejandra Pizarnik uses to mask the subject: from the figure of the exiled, that one who knows herself expelled of her own being and of the real world; until that one that initiates a pilgrimage by two spaces that situate her in a “between”, all of them become not only a mask for the self, but also a significant with a subsequent meaning.

A lipid-mediated conformational switch modulates the thermosensing activity of DesK Inda, María Eugenia; Vandenbranden, Michel; Fernandez, Ariel; de Mendoza, Diego; Ruysschaert, Jean Marie; Cybulski, Larisa Estefania The thermosensor DesK is a multipass transmembrane histidine-kinase that allows the bacterium Bacillus subtilis to adjust the levels of unsaturated fatty acids required to optimize membrane lipid fluidity. The cytoplasmic catalytic domain of DesK behaves like a kinase at low temperature and like a phosphatase at high temperature. Temperature sensing involves a built-in instability caused by a group of hydrophilic residues located near the N terminus of the first transmembrane (TM) segment. These residues are buried in the lipid phase at low temperature and partially “buoy” to the aqueous phase at higher temperature with the thinning of the membrane, promoting the required conformational change. Nevertheless, the core question remains poorly understood: How is the information sensed by the transmembrane region converted into a rearrangement in the cytoplasmic catalytic domain to control DesK activity? Here, we identify a “linker region” (KSRKERERLEEK) that connects the TM sensor domain with the cytoplasmic catalytic domain involved in signal transmission. The linker adopts two conformational states in response to temperature-dependent membrane thickness changes: (i) random coiled and bound to the phospholipid head groups at the water-membrane interface, promoting the phosphatase state or (ii) unbound and forming a continuous helix spanning a region from the membrane to the cytoplasm, promoting the kinase state. Our results uphold the view that the linker is endowed with a helix/random coil conformational duality that enables it to behave like a transmission switch, with helix disruption decreasing the kinase/phosphatase activity ratio, as required to modulate the DesK output response.

Source limitations due to leaf rust (Puccinia Triticina) during grain filling period in wheat Serrago, Roman Augusto; Miralles, Daniel Julio Late foliar diseases (especially leaf rust) reduce assimilate supply during post-anthesis, determining fewer assimilates per grain and thereby inducing grain weight reductions. Although the assimilate reduction hypothesis is the most accepted to explain decreases in grain weight due to late foliar diseases, it has not been clearly established whether those reductions could be completely ascribed to source limitations or whether diminished grain weight could be the consequence of reductions in grain weight potential. The objective of this work was to determine whether grain weight reductions due to leaf rust during grain filling could be associated with source?sink limitations. Two experiments (during 2007 and 2008 growing seasons) including healthy and diseased wheat crops were conducted under field conditions. Source?sink manipulation treatments and grain water content measurements were made to test the source- and sink- limitation hypotheses due to the appearance of late foliar diseases during grain filling. Leaf rust was induced to appear exclusively during grain filling, and in both years, it reduced grain yield and grain weight in both experiments. However, except for distal grains, there were no significant differences between healthy and diseased plots in maximum grain water content, indicating that late foliar diseases did not affect the potential size of the grains. The reserves stored in stems were remobilised to the growing grains in both healthy and diseased crops. However, the reserves remaining at physiological maturity were significantly reduced in diseased crops. Reduction in grain number by trimming the spikes increased the grain weight in diseased but not in healthy crops. Grain weight of trimmed spikes in diseased crops reached similar values to those of healthy crops. These results support the hypothesis that foliar diseases could cause source limitation for grain filling beyond differences in grain weight potential when the crops are severely affected by late foliar diseases such as leaf rust.

Servir en la Corte de los Reyes Católicos: dominicos en los oficios de tutor de príncipes y embajador (1490-1516); Serving at the Court of the Catholic Monarchs: Dominicans in the office of tutor of princes and ambassador (1490-1516) Nieva, Guillermo René La relación entre dominicos observantes y monarcas castellanos durante el reinado de los Reyes Católicos se articuló en torno a la actividad de patrocinio regio sobre los conventos de la Orden de Predicadores y al servicio de los frailes en la Corte. Algunos de esos religiosos recibieron el encargo de educar a los príncipes, situación que en general les permitió iniciar una ascendente carrera política y eclesiástica. De hecho, varios de ellos destacaron como embajadores al servicio del rey Fernando hasta el final de su reinado. Tal es el caso de fray Tomás de Matienzo y de fray Bernardo de Mesa,activos miembros de aquella agrupación que José Martínez Millán ha denominado ?partido fernandino?. En el presente estudio se analizarán las trayectorias vitales de ambos personajes, ya sea como vehículos de ciertas corrientes de espiritualidad sumamente atractivas entre los miembros de la aristocracia castellana a principios del siglo XVI, así como en su rol específico de agentes de la política exterior sostenida por la "facción fernandina". En este último sentido, examinaremos en particular la cuestión de los beneficios que podía crear a los monarcas el reclutamiento de religiosos en su personal diplomático.; The relationship between observant Dominicans and Castilian monarchs during the reign of the Catholic Monarchs was articulated around the activity of royal patronage on the convents of the Order of Preachers and the service of the friars in the Court. Some of these religious received the task of educating princes, situation that generally allowed them to start an ascending political and ecclesiastical career. In fact, several of them highlighted as ambassadors in the service of King Ferdinand until the end of his reign. Such is the case of fray Tomás Matienzo and fray Bernardo de Mesa, active members of that group José Martínez Millán called “partido fernandino”. This study will explore the vital trajectories of both figures, either as vehicles of certain currents of spirituality extremely attractive among the members of the Spanish aristocracy in the early 16th century, as well as its specific role as agents of foreign policy held by “facción fernandina”. In the latter sense, we will examine in particular the question of the benefits the monarchs could obtain from the recruitment of religious in its diplomatic personnel.

Una edad U-Pb SHRIMP (Carniano) para el Grupo Puesto Viejo, depocentro de San Rafael Ottone, Eduardo Guillermo; Monti, Mariana; Marsicano, Claudia Alicia; de la Fuente, Marcelo Saul; Naipauer, Maximiliano; Armstrong, Richard; Mancuso, Adriana Cecilia El Grupo Puesto Viejo incluye, de base a techo, las formaciones Quebrada de los Fósiles y Río Seco de la Quebrada (Stipanicic et al. 2007). La Formación Quebrada de los Fósiles contiene restos paleoflorísticos saltuarios y escasos niveles con palinomorfos, que reflejan una asociación donde abundan las esfenofitas y pleuromeiales (Ottone y García 1991). En la unidad también hay tetrápodos dicinodontes y un arcosauromorfo basal (Koilamasuchus gonzalezdiazi), correlacionados con la Zona de Lystrosaurus AZ, referida en Sudáfrica al Induano (Triásico Inferior bajo). La suprayacente Formación Río Seco de la Quebrada presenta restos de sinápsidos, tanto dicinodontes (Kanameyeria argentina y Vinceria sp.) como cinodontes (Cynognathus crateronotus, Diademodon tetragonus y Pascualognathus polanskii), que la correlacionarían con la Zona Cynognathus AZ, referida en Sudáfrica al Olenekiano hasta Anisiano (Triásico Inferior alto/ Triásico Medio) (Abdala et al. 2009, Martinelli et al. 2009). Trabajos recientes citaron en la Formación Quebrada de los Fósiles una palinoflora referida al Lopingiano (Pérmico alto), sugiriendo que en el Grupo Puesto Viejo podría estar representado el límite Permo/ Triásico (Zavattieri et al. 2003, Sepúlveda et al. 2007, Stipanicic et al. 2007). Nuestra datación U-Pb SHRIMP en la ignimbrita emplazada entre las formaciones Quebrada de los Fósiles y Río Seco de la Quebrada dio como resultado 235.8 ± 2.0 Ma (Carniano). Este dato plantea un nuevo marco deposicional para el Grupo Puesto Viejo, ajustando además la edad de sus fósiles, en especial las faunas de tetrápodos que, aunque comparten taxones con la Cuenca del Karoo, se habrían registrado ca. 10 Ma más tarde de lo propuesto para Sudáfrica. Nuestro resultado pone en dudas la validez del esquema bioestratigráfico sudafricano y su uso para correlacionar el Triásico Inferior a Medio de Gondwana, principalmente considerando que dicha secuencia carece de dataciones absolutas. Por otro lado, teniendo en cuenta que el Grupo Puesto Viejo habría comenzado a depositarse hacia el Triásico Medio y que rocas del techo de la infrayacente Formación Cerro Carrizalito fueron datadas por U-Pb SHRIMP en 251.9±2.7/6.6 Ma (ca. del límite Lopingiano/Triásico) (Rocha-Campos et al. 2011), se concluye que el pasaje entre el Pérmico y el Triásico no estaría representado en el Grupo Puesto Viejo.

Tetrapod swimming/wading traces in Lower Cretaceous marginal-marine environments from Patagonia:distribution and paloebathimetric implications Fernández, Diana Elizabeth; Pazos, Pablo Jose During the past few years, the first integrated ichnological/sedimentological research of Lower Cretaceous, marginal-marine units from the Neuquén basin (Northern Patagonia, Argentina) has been carried out. Most of the ichnofossils included in those studies were invertebrate trace fossils. Only some were assigned to vertebrates (non-avian theropod dinosaurs, in particular). The aim of the present work is to communicate the presence of tetrapod swimming traces in two Lower Cretaceous units of this basin, to describe them and to inform of their use as paleobathymetric tools in a case study. The Neuquén Basin contains over 7000 m thick marine and continental deposits of Late Triassic to Paleogene age. The material analyzed in this work comes from two units: the Mulichinco Formation and the Agua de la Mula Member or Upper Member of the Agrio Formation (Mendoza Group). The first unit is a mainly clastic, marine to continental succession of early Valanginian age. Nearby the study area, the Mulichinco Formation comprises clastic and carbonate lithologies that have been interpreted as deposited in non-deltaic, open shallow marine environments. The second unit is a Late Hauterivian?Early Barremian mixed carbonate?siliciclastic marine and marginal-marine succession. In five localities, bi or tridactyl hypichnial marks composed of elongate, parallel, straight to slightly curved ridges were found. Some of the terminations are reflexed. The sets of ridges are 48 mm up to 18 cm in length, and 17 mm up to 9 cm in width. We have previously reported isolated material. Even though the specimens continue to be scarce, it is possible to acknowledge that they are more abundant than previously thought. Some are provisionally assigned to Characichnos Whyte and Romano, and are ascribed to the activity of swimming or wading tetrapods of relatively small size. During the last years it has been confirmed that shallow and/or marginal-marine environments where common in the studied units. In levels where the direct sedimentological evidence was inconclusive, the presence of these trace fossils allowed to infer shallower depositional settings.

Resultados Paleomagnéticos preliminares del Grupo Mesón, Departamento de Santa Victoria, Provincia de Salta, Argentina Franceschinis, Pablo Reinaldo; Rapalini, Augusto Ernesto; Escayola, Monica Patricia; Luppo, Tomas Se presentan los resultados de un estudio paleomagnético preliminar de tres sitios ubicados en las areniscas rojas a moradas de la Formación Campanario perteneciente al Grupo Mesón, correspondiente al Cámbrico tardío temprano y de un sitio perteneciente a un dique ácido intruyendo al grupo Mesón, de edad desconocida. El estudio se llevó a cabo en el área de Santa Victoria Oeste, lugar definido por Turner (1964) como la localidad tipo de la subyacente Formación Puncoviscana.

El concepto de posición docente: notas conceptuales y metodológicas Southwell, Myriam; Vassiliades, Alejandro Las regulaciones del trabajo docente han sido posiblemente uno de los temas más abordados en los estudios de historia, política y sociología de la educación en los últimos años. Desde diversos marcos teóricos y epistemológicos, un vasto número de investigaciones se han dedicado a analizar la cuestión para aproximarse a dar cuenta de problemas tales como las relaciones entre educación escolar y reproducción social y cultural, los vínculos entre el trabajo docente y la producción o el combate de la desigualdad, las disputas en torno de derechos laborales de los profesores, las diversas orientaciones que el Estado y otros actores pretenden imprimir al trabajo de enseñar, los diversos modos en que los docentes recepcionan y resignifican las políticas públicas en educación, sus concepciones respecto de dicho trabajo y de los estudiantes, las formas de razonamiento en torno del género, la raza, la clase social y la diferencia que operan como fundamento de las prácticas de los enseñantes, entre otros temas de destacada relevancia en la agenda de investigación educativa de nuestro país y en la región.; From different theoretical and epistemological approaches, teaching practice has been thought as vocation, work, job and condition, concepts from which it has been intended to account for diverse problems built by the fields of pedagogy, didactics, and history and educational policy. In this article we aim to develop the way in which it would be possible to tackle it from the concept of teaching position, presenting a series of theoretical movements that sustain this option. We will focus on a group of contributions that post-foundational perspectives, and particularly the Political Discourse Analysis, have done, with theoretical and methodological consequences for the study of teaching work regulations. We will consider the open and contingent discursive configuration of social relations and identities and identifications as temporary suture and fixation processes, trying to account for the way in which the notion of subject positions gives way to other forms of considering those configurations and allows developing the concept of teaching position.

Expression of genes related with the rna-directed dna methylation (rddm) pathway in Eragrostis curvula sexual and apomictic genotypes Selva, Juan Pablo; Garbus, Ingrid; Romero, José Rodolfo; Pessino, Silvina Claudia; Leblanc, Olivier; Echenique, Carmen Viviana Apomixis in plants refers to a diverse group of developmental behaviors resulting in asexual reproduction through seeds. Apomictic individuals bypass both meiotic reduction and egg cell fertilization to produce offspring that are exact genetic replicas of the maternal plant. Given the established relationships between sexual and apomictic pathways, different models have been proposed to explain the occurrence of apomixis at the molecular level involving genetic and epigenetic mechanisms. Weeping lovegrass [Eragrostis curvula (Schrader) Nees] is an apomictic perennial grass native of Southern Africa. The type of apomixis present in the E. curvula is pseudogamous diplospory. There are recent evidences on the role played by certain proteins of the RdDM pathways involved in gametophytic apomixis expression, suggesting an epigenetic regulation of the trait. It was reported in maize that loss-of-function of the dmt103 and dmt102 methyltransferases genes partially mimics apomictic developments. Similarly, loss-of-function in ago104, a maize homolog of ago9, also results in apomixis-like traits, giving rise to up to 70% of functional unreduced female gametes. These data suggest that an epigenetic regulation plays a role on the establishment of apomixis. In this work we studied the expression of EcDmt102-like and EcAgo104-like genes associated to the RdDM pathway in flowers and leaves of sexual and apomictic E. curvula plants. Using RNA seq data was possible to obtain the complete cDNA sequence for both genes from both apomictic and sexual genotypes. The phylogenetic analysis indicated that these genes group together in the same clade with the corresponding ones of Arabidopsis and Zea mays. The EcDmt102-like and EcAgo104-like genes profiles were analyzed using qRT-PCR in leaves and different stages of reproductive tissue. The expression profile obtained for EcDmt102-like was relatively higher in reproductive tissue of sexual plants, being down-regulated in apomictic ones. Expression of this gene was not observed in leaves from both genotypes. The expression pattern of EcAgo104-like was complex and is still under study because occurrence of a putative alternative splicing in the apomictic genotypes is being analysed. Our results support the reported roles played by this genes in gametophytic apomixis in other plant species.

On the stapedial anatomy of non-mammaliaform cynodonts Gaetano, Leandro Carlos; Abdala, Fernando The stapes is known in several non-mammaliaform cynodonts although it has only been cursorily studied. Here we thoroughly analyze the stapedial anatomy of several basal cynodonts in a phylogenetic framework. Non-mammaliaform cynodonts stapes has two crurae and a stapedial foramen. The fused crurae may extend into medial and/or lateral platforms reducing the stapedial foramen relative size. The presence of straight crurae is the basal condition and the most widespread among non-mammaliaform cynodonts; however, variations of this morphology are recognized in the gomphodonts Langbergia, Trirachodon, Exaeretodon, and some specimens of Massetognathus. The anterior crus is more robust than the posterior one in most of the cynodonts analyzed. The opposite situation is registered in Exaeretodon, some specimens of Massetognathus, Probainognathus, and Morganucodon. The crurae are subequal in Scalenodon and some specimens of Galesaurus and Probainognathus. A relatively small stapedial foramen is observed in the basal non-mammaliaform cynodonts Platycraniellus, Procynosuchus, and Progalesaurus whereas it is larger in gomphodonts. The stapedial foramen size is highly variable intraspecifically in Galesaurus and Massetognathus. Procynosuchus and Thrinaxodon only have a lateral platform, whereas the presence of a single medial platform is synapomorphic of a more derived clade including Platycraniellus plus Eucynodontia. Galesaurus, Procynosuchus, and Thrinaxodon share the presence of a lateral ossified portion of the stapes wider than the medial one whereas the opposite situation is synapomorphic of gomphodonts and also observed in Platycraniellus. Anterior and/or posterior projections medially and/or laterally are inconsistently present in some of the cynodonts studied. These projections are not related to the insertion of soft tissues as it has been interpreted. Some of the taxa analyzed (Luangwa, Massetognathus, and Trirachodon) bear a delicate flange-like triangular dorsal process on the dorsal surface of the posterior crus pointing dorsally or dorsomedially. Its presence is variable intraspecifically and among closely related taxa. This process cannot be readily homologized with the tympanic process of more basal synapsids. The morphology of the dorsal process is compatible with the insertion of a small ligament or perhaps the stapedial muscle. The presence of a cartilaginous extrastapes contacting a postquadrate eardrum is not supported by the evidence available. The inclusion of characters provided by the stapes in a total evidence data matrix (including cranial, postcranial, and dental characters), showed that they are phylogenetically informative. Our analysis results in a better understanding of the auditory system in basal cynodonts and its evolution, highlighting the variability of the stapedial anatomy, even intraspecifically.

Características fisiológicas que permiten a Cabralea canjerana Mart. tolerar los cambios súbitos en la disponibilidad de luz Moretti, Ana Paula; Pinazo, Martín Alcides; Graciano, Corina La etapa de regeneración de los bosques es una de las más importantes en el manejo de los mismos, así como la plasticidad que presenten las especies para aclimatarse a diferentes ambientes y condiciones cambiantes de luz. Cabralea canjerana Mart. (cancharana) tiene la capacidad de aclimatarse a los ambientes con disponibilidad de luz contrastante (sol pleno y canopeo denso) realizando modificaciones morfológicas y fisiológicas en el mediano plazo. El objetivo fue conocer la capacidad de respuesta de cancharana a cambios súbitos de cobertura, esto es, el pasaje de condición de sombra a luz plena, que simula la apertura de un claro en el bosque. Este cambio abrupto en la disponibilidad de luz no afectó la supervivencia de las plantas, aunque generó estrés hídrico y lumínico leve en las plantas aclimatadas a la sombra que fueron expuestas a luz plena. Ninguno de estos estreses repercutió negativamente en el crecimiento de las plantas.; Regeneration is one of the most relevant processes to manage native forests. In this stage of the forest dynamic, the acclimation of the species to changes in light environments is very important to ensure plant survivor and growth. Cabralea canjerana (cancharana) can acclimatate to contrasting light environments (sun in open areas and shade below a dense canopy) by modifying its morphology and physiology. The aim of this work was to evaluate the response of cancharana plants that were shade acclimated to sudden changes in light environment, i.e. simulating a gap opening in the forest. All the plants survived to the sudden change in light, but slight water and light stress was observed. Nevertheless, any of these stresses affected negatively growth.