Comparison between the continuum threshold and the Polyakov loop as deconfinement order parameters Carlomagno, Juan Pablo; Loewe, Marcelo We study the relation between the continuum threshold s0 within finite energy sum rules and the trace of the Polyakov loop Φ in the framework of a nonlocal SU(2) chiral quark model, establishing a contact between both deconfinement order parameters at finite temperature T and chemical potential μ. In our analysis, we also include the order parameter for the chiral symmetry restoration, the chiral quark condensate. We found that s0 and Φ provide us with the same information for the deconfinement transition, both for the zero and finite chemical potential cases. At zero density, the critical temperatures for both quantities coincide exactly and, at finite μ both order parameters provide evidence for the appearance of a quarkyonic phase.

An inside look at the sensory biology of triatomines Barrozo, Romina; Reisenman, Carolina Esther; Guerenstein, Pablo Gustavo; Lazzari, Claudio Ricardo; Lorenzo, Marcelo Gustavo Although kissing bugs (Triatominae: Reduviidae) are perhaps best known as vectors of Chagas disease, they are important experimental models in studies of insect sensory physiology, pioneered by the seminal studies of Wigglesworth and Gillet more than eighty years ago. Since then, many investigations have revealed that the thermal, hygric, visual and olfactory senses play critical roles in the orientation of these blood-sucking insects towards hosts. Here we review the current knowledge about the role of these sensory systems, focussing on relevant stimuli, sensory structures, receptor physiology and the molecular players involved in the complex and cryptic behavioural repertoire of these nocturnal insects. Odours are particularly relevant, as they are involved in host search and are used for sexual, aggregation and alarm communication. Tastants are critical for a proper recognition of hosts, food and conspecifics. Heat and relative humidity mediate orientation towards hosts and are also important for the selection of resting places. Vision, which mediates negative phototaxis and flight dispersion, is also critical for modulating shelter use and mediating escape responses. The molecular bases underlying the detection of sensory stimuli started to be uncovered by means of functional genetics due to both the recent publication of the genome sequence of Rhodnius prolixus and the availability of modern genome editing techniques.

Adsorption dynamics of molecular nitrogen at an Fe(111) surface Nosir, M. A.; Martin Gondre, L.; Bocan, Gisela Anahí; Díez Muiño, R. We present an extensive theoretical study of N2 adsorption mechanisms on an Fe(111) surface. We combine the static analysis of a six-dimensional potential energy surface (6D-PES), based on ab initio density functional theory (DFT) calculations for the system, with quasi-classical trajectory (QCT) calculations to simulate the adsorption dynamics. There are four molecular adsorption states, usually called γ, δ, α, and ε, arising from our DFT calculations. We find that N2 adsorption in the γ-state is non-activated, while the threshold energy is associated with the entrance channel for the other three adsorption states. Our QCT calculations confirm that there are activated and nonactivated paths for the adsorption of N2 on the Fe(111) surface, which is in agreement with previous experimental investigations. Molecular dynamics at a surface temperature Ts = 300 K and impact energies Ei in the 0-5 eV range show the relative occupancy of the γ, δ, α, and ε states. The δ-state, however, is only marginally populated despite its adsorption energy being very similar to that of the γ-state. Our QCT calculations trace the dependence of molecular trapping on the surface temperature Ts and initial impact energy Ei and quantify the rates of the different competitive channels that eventually lead to molecular adsorption.

Hydriding kinetics of Mg[sbnd]TiH2 fine dispersions obtained by mechanosynthesis Biasetti, Andrés Tobías; Meyer, Marcos; Mendoza Zélis, Luis Alejandro Mg80[sbnd]Ti20 hydride systems were prepared via reactive ball milling following two different procedures: grinding Mg with Ti or TiH2, in both cases under H2 atmosphere. Such systems were subjected to several cycles of hydrogen uptake and release in volumetric Sieverts apparatus under different pressure and temperature conditions. A structural characterization from SEM images and XRD patterns reveals no essential microstructural differences between the samples obtained by different routes, although a growth in domain size with temperature is observed. Also, the slowing of the kinetics when the temperature goes down is more pronounced in the specimen fabricated by the second route. The influence of the transformed and untransformed phase fractions on the absorption kinetics can be well described using a double Hill function. Such complex function takes into account two distinguishable processes, with and without nucleation, that differentiate themselves as temperature increases. The first one may be related to surface absorption and the second tentatively ascribed to reactions at grain boundaries, dislocations and other extended defects. The fitted values may then be associated to physical constants of the processes occurring during hydrogen absorption in both regions.

Marcadores de formación y resorción ósea y su utilidad para determinar el final del periodo de aposición ósea; Bone formation and resorption markers to evaluate the end of bone apposition Seijo, Mariana; Oliveri, María Beatriz; Deferrari, Juan Mariano; Casco, Cristina; Zeni, Susana Noemi El pico de masa ósea (PMO) se alcanza entre los 20 y 35 años, pero la aposición ósea continúa hasta alcanzar el pico de fortaleza ósea (PFO). Se crea así una ventana entre ambos picos que podría ser evaluada mediante marcadores bioquímicos de recambio óseo, ya que durante dicho período la densidad mineral permanece constante. El objetivo fue determinar el final de la aposición ósea mediante marcadores bioquímicos óseos. Se evaluaron por décadas entre 20 y 49 años de edad 139 sujetos sanos de ambos sexos (69 hombres y 70 mujeres), determinando fosfatasa alcalina ósea (FAO), osteocalcina (OC), propéptido amino terminal del colágeno tipo 1 (P1NP) y telopéptido C-terminal del colágeno tipo 1 (CTX). Los marcadores correlacionan negativamente con la edad (OC: r= -0,3; p<0,01; P1NP: r= -0,4; p< 0,01 y CTX: r= -0,4; p< 0,01), exceptuando FAO. En hombres de 20-29 años, P1NP y el CTX fueron significativamente mayores vs. 30-39 años (p<0,05 y p<0,001, respectivamente), y entre 30-39 años vs. de 40-49 años en P1NP y CTX (p<0,05; p<0,001, respectivamente). En mujeres de 20-29 años, P1NP y CTX fueron significativamente mayores vs. 30-39 años (p<0,0001 y p<0,01, respectivamente). Conclusión: los marcadores de remodelado óseo más sensibles y específicos permitirían determinar bioquímicamente el fin de la aposición ósea que se produce entre el PMO y el PFO. Si bien es necesario ampliar el número de sujetos evaluados, los datos que surgen de la presente investigación sentarían las bases para futuros estudios epidemiológicos referidos al fin de la aposición ósea.; Peak bone mass is achieved between 20- 35 years; however bone apposition continues to reach an optimal skeleton strength. The window between peak bone mass and peak bone apposition may be evaluated by biochemical bone turnover markers. The objective of this study was to determine the end of bone apposition through biochemical bone markers in both sexes. A total of 139 subjects (69 men and 70 women) were divided by decades between 20 and 49 years of age. Bone alkaline phosphatase (BAL), osteocalcin (OC), type I collagen propeptide (P1NP) and type I collagen C-terminal telopeptide (CTX) were evaluated. Except BAL, the other bone markers negatively correlated with the age [OC (r= -0.3; p<0.01); P1NP (r= -0.4; p<0.01) and CTX (r= -0.4; p<0.01)]. Regarding men aged 20 to 29 years, P1NP and CTX were significantly higher vs. 30-39 years (p<0.05 y p<0.001, respectively) and. vs. 40-49 years (p<0.05; p<0.001, respectively). In women, the results were similar. Regarding 20-29 years, P1NP and CTX were higher vs. 30-39 years (p<0.001 y p<0.01, respectively). Bone remodeling rate decreases after the third decade, suggesting the end of the apposition period of peak bone mass. Conclusion: The most specific and sensitive bone markers would biochemically determine the end of bone apposition that extends between the peak of bone mass and the peak of bone strength. Although it is necessary to increase the number of subjects evaluated, the data that emerge from the present study would establish the bases for future epidemiological studies referring to the end of bone apposition.

Conformational diversity analysis reveals three functional mechanisms in proteins Monzón, Alexander; Zea, Diego Javier; Fornasari, Maria Silvina; Saldaño, Tadeo Enrique; Fernández Alberti, Sebastián; Tosatto, Silvio C. E.; Parisi, Gustavo Daniel Protein motions are a key feature to understand biological function. Recently, a large-scale analysis of protein conformational diversity showed a positively skewed distribution with a peak at 0.5 Å C-alpha root-mean-square-deviation (RMSD). To understand this distribution in terms of structure-function relationships, we studied a well curated and large dataset of ~5,000 proteins with experimentally determined conformational diversity. We searched for global behaviour patterns studying how structure-based features change among the available conformer population for each protein. This procedure allowed us to describe the RMSD distribution in terms of three main protein classes sharing given properties. The largest of these protein subsets (~60%), which we call "rigid" (average RMSD = 0.83 Å), has no disordered regions, shows low conformational diversity, the largest tunnels and smaller and buried cavities. The two additional subsets contain disordered regions, but with differential sequence composition and behaviour. Partially disordered proteins have on average 67% of their conformers with disordered regions, average RMSD = 1.1 Å, the highest number of hinges and the longest disordered regions. In contrast, malleable proteins have on average only 25% of disordered conformers and average RMSD = 1.3 Å, flexible cavities affected in size by the presence of disordered regions and show the highest diversity of cognate ligands. Proteins in each set are mostly non-homologous to each other, share no given fold class, nor functional similarity but do share features derived from their conformer population. These shared features could represent conformational mechanisms related with biological functions.

Optimum PR Control applied to LCL filters with Low Resonance Frequency Fantino, Roberto Armin; Busada, Claudio; Solsona, Jorge Alberto A control strategy for LCL Grid-connected voltage source inverters is proposed. Using the injected grid current measurement exclusively, the proposal allows the use of the proportional plus resonant regulator (PR) optimum design, regardless of the filter resonance frequency. Simulation and experimental results that demonstrate the validity and effectiveness of the proposal for different LCL filter resonance frequency values are presented. Also its superiority compared to a control methodrecently proposed in the literature is shown.

NiNbO Catalyst Deposited on Anodized Aluminum Monoliths for the Oxidative Dehydrogenation of Ethane Santander, José Anibal; Boldrini, Diego Emmanuel; Pedernera, Marisa Noemi; Tonetto, Gabriela Marta Aluminum monoliths were used as substrates to prepare structured catalysts. A rough alumina layer was generated on the surface of the substrates by anodizing followed by hydrothermal treatments. The dip-coating technique was used for coating the monolithic substrates. Aqueous suspensions with 0.15 and 0.30 g/g of Ni-Nb mixed oxides catalysts were prepared for that purpose. Colloidal SiO2 was added as a binder in order to obtain homogeneous and adherent coatings. The samples were characterized by SEM, TPR, XPS, XRD, and N2 adsorption and tested in the oxidative dehydrogenation (ODH) of ethane to ethylene. The silica particles produced a drop in catalytic activity without affecting ethylene selectivity. The former effect was attributed mainly to a decrease in surface nickel concentration and an increase in reduction temperature. The presence of anodized aluminum substrates in the reaction environment did not have a significant influence on catalytic activity and product distribution, as observed for the coated monoliths used in this work, thus being a useful material to prepare structured catalysts for low-temperature ethane ODH.

Nest niche overlap among the endangered Vinaceous-breasted Parrot (Amazona vinacea) and sympatric cavity-using birds, mammals, and social insects in the subtropical Atlantic Forest, Argentina Bonaparte, Eugenia Bianca; Cockle, Kristina Louise Many forest bird species require tree cavities for nesting, and share this resource with a diverse community of animals. When cavities are limited, niche overlap can result in interspecific competition, with negative consequences for threatened populations. Vinaceous-breasted Parrots (Amazona vinacea) are endangered cavity nesters endemic to the subtropical Atlantic Forest, where cavities are scarce. We examined nest niche overlap among Vinaceous-breasted Parrots and 9 potential competitors (birds and mammals >140 g, and social insects) in Argentina, considering (1) timing of breeding, (2) characteristics of cavities (depth, entrance diameter, height), trees (diameter at breast height DBH, species, condition), and habitat (surrounding land use, distance to edge), and (3) interspecific cavity reuse. During 10 breeding seasons we studied nests and roosts, measured their characteristics, and monitored cavities to detect reuse. We used multinomial logistic regression to determine whether the 6 most abundant taxa differed in nest and roost site characteristics. Timing of breeding overlapped for all bird species except the White-eyed Parakeet (Psittacara leucophthalmus). No combination of cavity, tree, and habitat characteristics predicted the taxa that utilized cavities. Moreover, 8 of the 10 taxa reused cavities interspecifically. The high level of overlap in realized nest niche, combined with previous evidence that cavities could limit bird density in our study area, suggest the possibility of interspecific competition for cavities among multiple taxa. Although models did not perform well at classifying cavities by taxon, some characteristics of cavities, trees, and habitat were selected more by Vinaceous-breasted Parrots than by other taxa, and we recommend targeting conservation efforts toward cavities and trees with these characteristics (7-40 cm entrance diameter, >10 m high, DBH >55 cm). We found 62% of Vinaceous-breasted Parrot nests on farms (vs. ≤50% for other taxa), highlighting the importance of working with local farmers to conserve cavities in anthropogenic habitats as well as in protected areas.

A mucin-like peptide from Fasciola hepatica instructs dendritic cells with parasite specific Th1-polarizing activity Noya, Verónica; Brossard, Natalie; Rodríguez, Ernesto; Dergan Dylon, Leonardo Sebastian; Carmona, Carlos; Rabinovich, Gabriel Adrián; Freire, Teresa Fasciolosis is a trematode zoonosis of interest in public health and cattle production. We report here the immunostimulatory effect of a 66 mer mucin-like peptide from Fasciola hepatica (Fhmuc), which synergizes with lipopolysaccharide (LPS) to promote dendritic cell (DC) maturation, endowing these cells with Th1-polarizing capacity. Exposure of DCs to Fhmuc in presence of LPS induced enhanced secretion of pro-inflammatory cytokines and expression of co-stimulatory molecules by DCs, promoting their T cell stimulatory capacity and selectively augmenting IFN- secretion by allogeneic T cells. Furthermore, exposure of DCs to Fhmuc augmented LPS-induced Toll-like receptor (TLR) 4 expression on the cell surface. Finally, Fhmuc-conditioned DCs induced parasite specific-adaptive immunity with increased levels of IFN-gamma secreted by splenocytes from vaccinated animals, and higher parasite-specific IgG antibodies. However, DC-treated Fhmuc conferred modest protection against F. hepatica infection highlighting the potent immuno-regulatory capacity of the parasite. In summary, this work highlights the capacity of a mucin-derived peptide from F. hepatica to enhance LPS-maturation of DCs and induce parasite-specific immune responses with potential implications in vaccination and therapeutic strategies.

Synoptic taxonomy of cortaderia stapf (danthonioideae, poaceae) Testoni, Daniel; Linder, H. Peter Cortaderia (Poaceae; Danthonioideae) is a medium-sized genus of C3 tussock grasses, widespread in the temperate to tropic-alpine regions of South America. It is particularly important in the subalpine and alpine zones of the Andes. We revised the classification of the genus, and recognize 17 species grouped into five informal groups. We describe one new species, Cortaderia echinata H.P.Linder, from Peru. We provide a key to the groups and the species, complete nomenclature for each species including new lectotypes, and notes on the ecology, distribution and diagnostic morphological and anatomical characters.

Un nuevo Dasypodidae (Mammalia, Xenarthra) del Oligoceno temprano de Gran Barranca (Chubut, Argentina) Ciancio, Martin Ricardo; Carlini, Alfredo Armando Damos a conocer un nuevo Euphractini (Cingulata, Dasypodidae) hallado en sedimentos oligocenos de "La Cantera" (Gran Barranca, lago Colhue Huapi), portadores de una fauna única que representa un lapso post-Tinguiririquense a pre-Deseadense. Los sedimentos corresponden a depósitos tobáceos que constituyen el Miembro Puesto Almendra superior (Formación Sarmiento), datados en ca. 30,7 Ma (Oligoceno temprano). El material (AR-10-73) corresponde a un fragmento de coraza dorsal (más numerosos osteodermos sueltos asociados) que mide 9 cm de largo, y preserva 2 hileras de bandas móviles y 10 del escudo pélvico. De acuerdo a las características de los osteodermos, el espécimen corresponde a un Euphractini pequeño, de tamaño similar al de Zaedyus pichiy, que asignamos a una nueva especie de Parutaetus Ameghino, 1902. Los osteodermos fijos son pequeños, con una figura principal alargada, en forma de lágrima (invertida, más amplia proximalmente). Presentan usualmente un par de figuras anteriores, un par de figuras anterolaterales pequeñas (que forman una figura compuesta entre osteodermos adyacentes) y un par de figuras postero-laterales (más alargadas). Poseen numerosos forámenes pilíferos pequeños, restringidos al borde posterior. Sobre la cara externa del osteodermo hay pequeños forámenes (de 2 a 5) sobre el borde anterior de la figura central que, en la zona central del escudo pélvico, están más desarrollados conformando un surco en ?U? abierto hacia atrás, que podría representar un desarrollo glandular local mayor. Este material, además de permitirnos evaluar las características de la coraza, provee nueva información para evaluar la diversidad y conocer mejor relaciones filogenéticas de armadillos paleógenos.

La reformulación del escenario político en clave peronista (1943-1955) Lichtmajer, Leandro Ary Con el derrocamiento de Castillo, el 4 de junio de 1943, culminó abruptamente el ciclo político abierto trece años antes. En el tramo final de su mandato, el vicepresidente en ejercicio navegaba las turbulentas aguas de un escenario dominado por el conflicto bélico internacional y por las impugnaciones que, desde diversos ángulos del arco político, se esgrimían a un gobierno dotado de bases endebles de legitimidad. En ese sentido, el fracaso de la tentativa de Ortiz por desandar las prácticas fraudulentas fue seguido por una etapa de afianzamiento conservador en desmedro del antipersonalismo. Como vimos, este proceso impactó de lleno en la dinámica política tucumana, al favorecer el desplazamiento del radicalismo concurrencista en manos de una intervención federal.

Migrantes senegaleses en Argentina: Contexto sociopolítico-laboral y vulneración de derechos Goldberg, Alejandro; Sow, Papa A través del análisis de una serie de entrevistas efectuadas a M. Mas-sar Ba, nos proponemos en este capítulo explorar las tramas de violencia institucional y para-institucional (Marmer y Sow, 2015) que, cada vez en mayor cantidad e intensidad, se ejecutan en el actual contexto sociopolítico nacional contra diferentes grupos que conforman los sectores subalternos de la sociedad argentina. Para abordar la problemática apuntada, nos cen-tramos particularmente en los migrantes senegaleses. En primer término, indagaremos en la genealogía de algunas de las concepciones hegemónicas sobre la otredad, la integración diferencial de los inmigrantes y la gestión socioterritorial de la diversidad en Argentina por parte de las élites gober-nantes, focalizando en la ciudad de Buenos Aires. En segundo lugar, repa-samos de forma breve el proceso migratorio senegalés en Argentina, desde sus antecedentes en el siglo XIX hasta las características del flujo migratorio actual, que comienza a manifestarse, principalmente, en la primera década de este milenio y continúa hasta la actualidad. Seguidamente, presentamos un análisis de los resultados de nuestras investigaciones priorizando dos aspectos interrelacionados: el ámbito laboral mayoritario de los migrantes senegaleses, esto es, la venta ambulante y el asociacionismo transnacional senegalés. Cerramos el capítulo con unas consideraciones finales.

"Brasil, decime qué se siente": Fútbol, música, narcisismo y estado, o el fracaso de Mascherano Alabarces, Pablo Alejandro A comienzos de los años 60, un grupo de jóvenes norteamericanos, más precisamente californianos, que habían nacido todos en 1945 y se llamaban John Fogerty, Doug Clifford y Stu Cook, formaron una banda de rock, como tantas otras que se formaban en esa época (o mejor aún: desde esa época hasta la actualidad) en California, en la costa oeste norteamericana. Eran de una pequeña ciudad llamada El Cerrito, al norte de San Francisco. Primero se llamaron The Blue Velvets, un nombre con algo de ridículo y algo de sonoro; era la época en que, por ejemplo, el cantante argentino Roberto Sánchez se hacía llamar Sandro y tenía una banda que se llamaba Los Caniches de Oklahoma. Era muy usual en esos años ponerle ese tipo de nombres a los grupos musicales, en la senda que habían abierto Bill Halley & The Comets a comienzos de los años 50 y luego profundizarían The Beatles, The Rolling Stones o The Doors, para mencionar sólo algunos; o en el caso argentino, Industria Nacional o Pintura Fresca (nombres ya depurados de la desenfrenada influencia anglófona).

Evaluación de la aptitud biológica de una población de nabo silvestre (Brassica rapa) con el transgen de resistencia a glifosato Pandolfo, Claudio Ezequiel; Presotto, Alejandro Daniel; Vercellino, Román Boris; Ureta, Soledad; Cantamutto, Miguel; Poverene, Mónica Brassica rapa (nabo) es una brasicácea anual, cuyas poblaciones silvestres son importantes invasoras de cultivos en todo el mundo, incluyendo la Argentina. Está emparentada con la colza canola (B. napus), cultivo de gran importancia a nivel mundial, que posee variedades transgénicas prohibidas en Argentina. Durante 2012, en el sudeste de la provincia de Buenos Aires, fueron halladas poblaciones de B. rapa resistentes a glifosato y se comprobó que la resistencia era de origen transgénico. El objetivo fue determinar si la presencia del transgen en estos biotipos implicaba un costo biológico. Se utilizó una población segregante para el carácter de resistencia y se seleccionaron mediante un test inmunológico 15 plantas con y sin la presencia de la proteína CP4 EPSPS, de origen transgénico. Las plantas se criaron a campo en condiciones de aislamiento y durante el ciclo se midieron caracteres de crecimiento y reproductivos. No se hallaron diferencias entre los dos grupos de plantas para los caracteres de altura, número de ramas, silicuas por inflorescencia y por planta. En el rendimiento total por planta se observó una tendencia a favor de los individuos sin el transgen, pero esta diferencia no fue significativa. Al contrario, las plantas transgénicas tuvieron más semillas por silicua, pero esto no se tradujo en diferencias en el número total de semillas por planta. Esto demostró que la presencia del transgen no disminuiría la aptitud biológica de esta población de B. rapa y su dispersión en ambientes ruderales sin presión de selección por glifosato no se vería limitada.

Caracterización de la actividad adrenocortical de Tamandua tetradactyla (Xenarthra: Pilosa) mediante la evaluación de la sensibilidad y la robustez Eguizabal, Gabina Victoria; Busso, Juan Manuel La respuesta adrenocortical al estrés resulta en un incremento de los glucocorticoides (GC) circulantes. Las evidencias en vertebrados indican que la magnitud del cambio a los desafíos ambientales (disponibilidad de alimento, ciclos de luz/oscuridad, etc.) varía según las características individuales (ej. historia de vida). Por lo tanto, los estudios de estrés fisiológico pueden beneficiarse evaluando a priori la sensibilidad y la robustez de la actividad adrenocortical. En el presente estudio, se evaluaron estas características en 3 machos y 3 hembras de Tamandua tetradactyla alojados individualmente en el Zoológico Córdoba. Para ello, se administró hormona adrenocorticotropina (ACTH i.m.; 0,5UI/kg) y dexametasona (Dexa i.m.; 0,1mg/kg), y se estudiaron las concentraciones de metabolitos de glucocorticoides fecales (MGF). Los porcentajes de cambio en las concentraciones de MGF se calcularon considerando el valor previo y el pico posterior al tratamiento para ACTH, y la inversa para Dexa. Por ejemplo, ACTH= 11,2*100/4,1 μg/g y Dexa= 100-(0,7*100/5,2) ug/g. Se observaron diferencias individuales en la respuesta a ACTH, siendo el incremento promedio de 303,4 ± 66,4% (CV 49%). Por su parte, el decremento por Dexa fue más homogéneo entre los ejemplares: 84,4 ± 1,63% (CV 4%). Considerando que la respuesta adrenocortical a ACTH reflejaría la capacidad máxima de secreción de GC, los resultados obtenidos permitirían clasificar las mediciones futuras dentro del rango funcional (respuesta adaptativa) o fuera del mismo (respuesta deletérea) de los ejemplares. El tratamiento con dexametasona confirmó que los animales exhibieron modulación de la actividad adrenocortical, lo que demuestra que no estarían en estado de estrés crónico. La aplicación de esta prueba farmacológica combinada en condiciones controladas, evaluada mediante técnicas no invasivas, podría ser útil no solo para clasificar a los individuos según su capacidad de reacción a los estímulos sino para sustentar pautas de manejo en el área de la fisiología de la conservación.

Brucella abortus-stimulated platelets actívate brain microvascular endothelial cells Rodríguez, Ana María; Trotta, Aldana; Miraglia, Maria Cruz; Delpino, María Victoria; Barrionuevo, Paula; Giambartolomei, Guillermo Hernan Central nervous system invasion by bacteria of the genus Brucella results in an inflammatory disorder called neurobrucellosis. Bloodbrain barrier activation is a common feature of human neurobrucellosis, but the underlying mechanisms are largely unknown. The aim of this work was to investigate the influence of B. abortus (B.a.)-activated platelets (PTL) on human brain microvascular endothelial cells (HBMEC). For this, supernatants (SN) from B.a.-stimulated human PTL were used to stimulate HBMEC. Expression of ICAM-1 (CD54) and secretion of IL-6, IL-8 and MCP-1 were evaluated to determine HBMEC´ activation. SN from B.a.-stimulated PLT induced a significant secretion of IL-6, IL-8, MCP-1 and the up-regulation of CD54 expression in a dose-dependent manner compared with SN from unstimulated PLT (p<0.001).To avoid the possible implication of B.a. outer membrane vesicles (OMV) we ultra-centrifuged the SN (to eliminate OMV). HBMEC were stimulated with ultra-centrifuge SN and we observed no differences on HBMEC’ activation compared with non-centrifuge SN (p>0.05), demonstrating that a soluble factor released from PLT was implicated on HBMEC’ activation. SN from heat-killed B.a.-stimulated PTL also activated HBMEC indicating that B.a.’ viability was not necessary in activating PLT. Soluble CD40L was not implicated on HBMEC’ activation, as an anti-CD40L antibody could not block cytokine secretion or ICAM-1 up-regulation. Treatment of SN with trypsin eliminate the effect (p<0.0005), demonstrating that the PLT effector is a protein. These results demonstrate that B.a.-stimulated PTL can activate brain endothelial cells, and this could be implicated on the entry to B.a. to the central nervous system

Novedoso ingrediente funcional: Liposoma con ácido linoleico conjugado Vélez, María Ayelén; Perotti, Maria Cristina; Hynes, Erica Rut; Gennaro, Ana Maria Publicación del proyecto en catálogo.Novedoso ingrediente funcional: liposomas con ácido linoleico conjugado. Novedoso ingrediente alimentario con ácidos grasos bioactivos (ácido linoleico conjugado CLA) en liposomas. Sus propiedades funcionales son la reducción del colesterol, aumento de las defensas y efecto antioxidante.

A new langmuir-schaefer-based method developed for catalytic studies of acetylcholinesterase in planar films of erythrocyte membranes Felsztyna, Iván; Perillo, Maria Angelica; Clop, Eduardo Matias Previously we reported that the catalytic activity of bovine erythrocyte acetylcholinesterase (BEA) located in Langmuir-Blodgett films (LB) of bovine erythrocyte membranes (BEM), LBBEA, depended on the curvature and packing of the molecular environment. Moreover, the specific activity of LBBEA was much lower than that of BEA in suspensions of BEM vesicles (SBEA). So, the present work was aimed at maximizing the specific activity of BEA recovered from the transfer of a Langmuir film (LF) from the air-aqueous interface to alkylated solid surfaces and improving the precision of the enzymatic assays. Three main changes were introduced to the previously assayed method. a) Phosphate saline buffer (PBS), pH 7.4 was used instead of H2O as the subphase over which was spread the BEM to form the LF, assuming that this composition, closer to physiological conditions, would be more effective than water in preserving the BEA protein structure/activity and the LF organization. b) BEA in LF films (LFBEA) was transferred from air-PBS interface to hydrophobic flat surfaces by the LangmuirSchaefer technique (LS) to obtain LSBEA samples. c) A new device was designed to allow performing the whole enzymatic activity assay using a unique LS film as well as the reading of the absorbance values in the same container. The LF of BEM at the air-PBS interface, compared with LF formed over H2O, showed surface pressure vs area (π-A) isotherms more expanded at low π, more compressible, with a bi-dimensional transition at lower π and lower minimal A. The surface potential reached 250 mV at the collapse point in both conditions (H2O and PBS). The specific activity resulted SBEA>>LSBEA>LBBEA. The use of PBS in the subphase and the transfer of LF at π=35mN/m instead of 10 mN/m improved the recovery of specific activity in LSBEA and LBBEA. The homogeneity of BEA distribution in LSBEA samples highly improved the precision of the kinetic parameters determined in different molecular packing conditions.