Alkaloids from Habranthus tubispathus and H. jamesonii, two amaryllidaceae with aAcetyl- and butyrylcholinesterase inhibition activity Cavallaro, Valeria; Alza, Natalia Paola; Murray, María Gabriela; Murray, Ana Paula Alzheimer´s disease (AD) is a neurodegenerative disorder associated with memory impairment and cognitive deficit. Most of the drugs currently available for the treatment of AD are acetylcholinesterase (AChE) inhibitors. Plants of the Amaryllidaceae family are known to synthesize alkaloids, which have shown AChE inhibitory activity. Habranthus tubispathus and H. jamesonii are two Amaryllidaceae that can be found growing wild to the southwest of Buenos Aires in Argentina. Acetyl- and butyrylcholinesterase inhibition was observed for the extracts obtained from bulbs of H. tubispathus and bulbs and aerial parts of H. jamesonii. The strongest cholinesterase inhibition was observed for the alkaloid extract obtained from the aerial parts for H. jamesonii (AChE IC50= 0.7 µg/mL; BChE IC50= 6.7 µg/mL). The AChE inhibition observed for H. jamesonii could be explained by the presence of galanthamine and sanguinine, two potent AChE inhibitors. The levels of lycorine and hippeastidine, moderate AChE inhibitors, observed in the bulbs of H. tubispathus could be responsible for the significant AChE inhibition observed. The alkaloids present in these Amaryllidaceae were identified by means of GC-MS analysis. In the case of H. tubispathus, hippeastidine and 3-O-demethylhippeastidine, were isolated and completely characterized by 1H and 13C NMR spectroscopy.

The family Caecidae (Gastropoda: Caenogastropoda) in Argentine waters Pastorino, Guido; Chiesa, Ignacio Luis This is the first formal report of members of the family Caecidae in Argentine waters. Caecum striatum de Folin, 1868, C. strigosum de Folin, 1868, and C. achirona (de Folin, 1867) are re-described from shallow waters off Piedras Coloradas ( 4053.0810 S, 6507.5920 W), Rı´o Negro Province, Argentina. This is the farthest south record of these species which were previously recorded from USA, Bahamas, Panama, Brazil, and Uruguay. The authors also make observations about the different ontogenetic stages of the studied species. Scanning electron microscope illustrations of radula and operculum are provided for the first time.

Categorías: los 30 primeros años Dubuc, Eduardo Julio El lector debe tener en cuenta que esta recopilación de los 30 primeros años de vida de la teoría de categorías responde a lo que puedo recordar, y no es el resultado de una investigación histórica sobre el desarrollo de la misma. El relato tiene como hilo conductor las veintiuna referencias primarias que aparecen por orden cronológico al final del artículo, las secundarias irán en notas a pie de página. Asimismo, he querido que estas notas sean un fiel reflejo de la conferencia impartida en octubre de 2013 en la ENHEM 41 , de contenido acotado por el tiempo, y no incluyen ni más ni menos que lo allí dicho. Quiero agradecer a los organizadores de la ENHEM 4, y en particular a Luis Recalde, el haberme invitado a la Escuela, sin lo que este trabajo nunca hubiese visto la luz.

NetMHCstab – predicting stability of peptide–MHC-I complexes; impacts for cytotoxic T lymphocyte epitope discovery Jørgensen, Kasper W.; Rasmussen, Michael; Buus, Søren; Nielsen, Morten Major histocompatibility complex class I (MHC-I) molecules play an essential role in the cellular immune response, presenting peptides to cytotoxic T lymphocytes (CTLs) allowing the immune system to scrutinize ongoing intracellular production of proteins. In the early 1990s, immunogenicity and stability of the peptide–MHC-I (pMHC-I) complex were shown to be correlated. At that time, measuring stability was cumbersome and time consuming and only small data sets were analysed. Here, we investigate this fairly unexplored area on a large scale compared with earlier studies. A recent small-scale study demonstrated that pMHC-I complex stability was a better correlate of CTL immunogenicity than peptide–MHC-I affinity. We here extended this study and analysed a total of 5509 distinct peptide stability measurements covering 10 different HLA class I molecules. Artificial neural networks were used to construct stability predictors capable of predicting the half-life of the pMHC-I complex. These predictors were shown to predict T-cell epitopes and MHC ligands from SYFPEITHI and IEDB to form significantly more stable MHC-I complexes compared with affinity-matched non-epitopes. Combining the stability predictions with a state-of-the-art affinity predictions NetMHCcons significantly improved the performance for identification of T-cell epitopes and ligands. For the HLA alleles included in the study, we could identify distinct sub-motifs that differentiate between stable and unstable peptide binders and demonstrate that anchor positions in the N-terminal of the binding motif (primarily P2 and P3) play a critical role for the formation of stable pMHC-I complexes. A webserver implementing the method is available at www.cbs.dtu.dk/services/NetMHCstab.

An Observing System Simulation Experiment (OSSE) for the Aquarius/SAC-D soil moisture product Bruscantini, Cintia Alicia; Crow, Wade T.; Grings, Francisco Matias; Perna, Pablo Alejandro; Maas, Martín Daniel; Karszenbaum, Haydee An Observing System Simulation Experiment (OSSE) for the Aquarius/SAC-D mission has been developed for assessing the accuracy of soil moisture retrievals from passive L-band remote sensing. The implementation of the OSSE is based on the following: a 1-km land surface model over the Red-Arkansas River Basin, a forward microwave emission model to simulate the radiometer observations, a realistic orbital and sensor model to resample the measurements mimicking Aquarius operation, and an inverse soil moisture retrieval model. The simulation implements a zero-order radiative transfer model. Retrieval is performed by direct inversion of the forward model. The Aquarius OSSE attempts to capture the influence of various error sources, such as land surface heterogeneity, instrument noise, and retrieval ancillary parameter uncertainty, all on the accuracy of Aquarius surface soil moisture retrievals. In order to assess the impact of these error sources on the estimated volumetric soil moisture, a quantitative error analysis is performed by comparison of footprint-scale synthetic soil moisture with “true” soil moisture fields obtained from the direct aggregation of the original 1-km soil moisture field input to the forward model. Results show that, in heavily vegetated areas, soil moisture retrievals have a positive bias that can be suppressed with an alternative aggregation strategy for ancillary parameter vegetation water content (VWC). Retrieval accuracy was also evaluated when adding errors to 1-km VWC (which are intended to account for errors in VWC derived from remote sensing data). For soil moisture retrieval root-mean-square error on the order of 0.05 m3/m3, the error in VWC should be less than 12%.

The role and status of English in Spanish-speaking Argentina and its education system: nationalism or imperialism? Porto, Melina There is a lot of controversy nowadays in the field of English Language Teaching (ELT) in the context of Teaching English to Speakers of Other Languages (TESOL) regarding the status and role of English in non-English speaking countries, in particular in developing countries, as well as in English-speaking countries with a history of colonialism. In these settings, the discourse of English as a form of imperialism requires a reconsideration of the role and status of English in the national school curriculum in primary and secondary school contexts. It also requires the exploration of the connections with nationalism and national identity, for within this discourse of imperialism, English tends to be seen as detrimental to the national identity, which education explicitly aims to form and develop through formal schooling.

Prenatal stress changes the glycoprotein GPM6A gene expression and induces epigenetic changes in rat offspring brain Monteleone, Melisa Carolina; Adrover, Ezequiela; Pallares, Maria Eugenia; Antonelli, Marta Cristina; Frasch, Alberto Carlos C.; Brocco, Marcela Adriana Prenatal stress (PS) exerts strong impact on fetal brain development and on adult offspring brain functions. Previous work demonstrated that chronic stress alters the mRNA expression of GPM6A, a neuronal glycoprotein involved in filopodium extension. In this work, we analyzed the effect of PS on gpm6a expression and the epigenetic mechanisms involved. Pregnant Wistar rats received restraint stress during the last week of gestation. Male offspring were sacrificed on postnatal days 28 and 60. Hippocampus and prefrontal cortex samples were analyzed for gene expression (qPCR for mRNAs and microRNAs), methylation status (bisulfite conversion) and protein levels. Hippocampal neurons in culture were used to analyze microRNA overexpression effects. Prenatal stress induced changes in gpm6a levels in both tissues and at both ages analyzed, indicating a persistent effect. Two CpG islands in the gpm6a gene were identified. Variations in the methylation pattern at three specific CpGs were found in hippocampus, but not in PFC samples from PS offspring. microRNAs predicted to target gpm6a were identified in silico. qPCR measurements showed that PS modified the expression of several microRNAs in both tissues, being microRNA-133b the most significantly altered. Further studies overexpressing this microRNA in neuronal cultures showed a reduction in gmp6a mRNA and protein level. Moreover filopodium density was also reduced, suggesting that GPM6A function was affected. Gestational stress affected gpm6a gene expression in offspring likely through changes in methylation status and in posttranscriptional regulation by microRNAs. Thus, our findings propose gpm6a as a novel target for epigenetic regulation during prenatal stress.

Geomagnetic effects on cosmic ray propagation under different conditions for Buenos Aires and Marambio, Argentina Masías Meza, Jimmy Joel; Dasso, Sergio Ricardo The geomagnetic field (Bgeo) sets a lower cutoff rigidity (Rc) to the entry of cosmic particles to Earth which depends on the geomagnetic activity. From numerical simulations of the trajectory of a proton using different models for Bgeo (performed with the MAGCOS code), we use backtracking to analyze particles arriving at the location of two nodes of the net LAGO (Large Aperture Gamma ray burst Observatory) that will be built in the near future: Buenos Aires and Marambio (Antarctica), Argentina. We determine the asymptotic trajectories and the values of Rc for different incidence directions, for each node. Simulations were done using several models for Bgeo that emulate different geomagnetic conditions. The presented results will help to make analysis of future observations of the flux of cosmic rays done at these two LAGO nodes.

Effect of cultivars and planting date on yield, oil content, and fatty acid profile of flax varieties (Linum usitatissimum L.) Gallardo, Maricel Andrea; Milisich, Héctor José; Drago, Silvina Rosa; González, Rolando José In order to determine the effect of cultivars and planting date on flax fatty acid profile, seed yield, and oil content, an assay with seven cultivars (Baikal, Prointa Lucero, Prointa Ceibal, Panambí INTA, Curundú INTA, Carapé INTA, and Tape INTA) was carried out at Parana Agricultural Experimental Station, Argentina. Significant differences among cultivars were found for content of palmitic (5–7 g/100 g), stearic (5–8 g/100 g), linoleic (13–19 g/100 g), saturated (11–15 g/100 g), and unsaturated acids (92–96 g/100 g) within the seven cultivars. The best seed yields were observed in Prointa Lucero and Carapé INTA varieties (2091.50 kg·ha−1 and 2183.34 kg·ha−1, respectively) in the first planting date and in Carapé INTA and Prointa Lucero (1667 kg·ha−1 and 1886 kg·ha−1, respectively) in the second planting date. A delayed planting date had a negative effect on seed yield (1950 kg·ha−1 and 1516 kg·ha−1) and oil content (845 kg·ha−1 and 644 kg·ha−1) but did not affect oil composition.

A regional audit of nitrogen fluxes in pampean agroecosystems Alvarez, Roberto; Steinbach, Haydée; de Paepe, Josefina Calculations of nitrogen (N) budgets can help in the understanding of agroecosystem functioning and in proposing more sustainable management strategies. Changes in the main N fluxes of the pampean agroecosystems of Argentina were calculated over time. The impact of management changes on regional N budget and possible future trends were estimated. Changes in land use were quantified using national censuses data. Biological N fixation of leguminous forages was assessed using a regression model and local field experimental data. Nitrogen fixation by soybean, the most extensive grain crop, was calculated using an existing model. Fertilizer input was based upon farmer surveys, and atmospheric N input estimated using local data. Nitrogen output by grain harvest was estimated using national yield statistics and averaged grain N concentration derived from many field experiments widespread over the region. During the last 50 years cropped area has doubled as a result of the widespread adoption of soybean as the main component of rotations. The agricultural expansion included areas previously used for grazing on seeded pastures and seasonal graminaceus forages. The historical N budget of the entire region was positive but has dropped from 2.0 Mt y−1 in 1960 to 1.3 Mt y−1 at present. This reduction implies that N fixation by soybean and fertilizer application were lower than the previous livestock/pasture systems N input. During the cropping phase of rotations the N budget was usually negative in the past. Currently, in low yielding areas of semiarid environments, the N budget turned positive; meanwhile in humid climates with high productivity scenarios it remained negative. Fertilizer rates applied balanced N output in the former case but not in the latter. Partial factor productivity of N inputs increased from 3- to 6-fold during the last 50 years in the Pampas. Uncertainties related to the estimations performed are discussed.

Characterization and bacterial adhesion of chitosan-perfluorinatedacid films Bierbrauer, Karina Lilian; Alasino, Roxana Valeria; Muñoz, Adrián; Beltramo, Dante Miguel; Strumia, Miriam Cristina We reported herein the study and characterization of films obtained by casting of chitosan solutions in perfluorinated acids, trifluoroacetic (TFA), perfluoropropionic (PFPA), and perfluorooctanoic (PFOA). The films were characterized by FTIR, solid state 13C NMR, X-ray, AFM, contact angle, thermogravimetric effluent analysis by mass spectrometry, and rheology. The results showed a marked influence of chain length of the perfluorinated acids on the hydrophobic/hydrophilic ratio of the modified chitosan films which was evidenced by the different characteristics observed. The material that showed greater surface stability was chitosan-PFOA. Chitosan film with the addition of PFOA modifier became more hydrophobic, thus water vapor permeability diminished compared to chitosan films alone,this new material also depicted bacterial adhesion which,together with the features already described, proves its potential in applications for bioreactor coating.

Hyperhalophilic archaeal biofilms: growth kinetics, structure and antagonistic interaction in continuous culture Di Meglio, Leonardo Gabriel; Busalmen, Juan Pablo; Pastore, Juan Ignacio; Ballarín, V. L.; Nercessian, Debora Biofilms by the hyperhalophilic archaea Halorubrum sp. and Halobacterium sp. were analyzed, and for the first time the progression of structural features and the developmental parameters of these sessile populations are described. Optical slicing and digital analysis of sequential micrographs showed that their three dimensional structure was microorganism dependent. Biofilms of Halobacterium sp. developed in clusters that covered about 30% of the supporting surface at the interface level and expanded over about 86 ± 4 μm in thickness, while Halorubrum sp. biofilms covered less than 20% of the surface and reached a thickness of 41 ± 1 μm. The kinetics of growth was lower in biofilms, with generation times of 27 ± 1 and 36 ± 2 h for Halobacterium sp. and Halorubrum sp., respectively, as compared to 8.4 ± 0.3 and 14 ± 1 h in planktonic cultures. Differences between microorganisms were also observed at the cell morphology level. The interaction between the two microorganisms was also evaluated, showing that Halobacterium sp. can outcompete already established Halorubrum sp. biofilms by a mechanism that might include the combined action of tunnelling swimmers and antimicrobial compounds.

Effect of a sublethal high-pressure homogenization treatment on the fatty acid membrane composition of probiotic lactobacilli Tabanelli, G.; Patrignani, F; Gardini, F.; Vinderola, Celso Gabriel; Reinheimer, Jorge Alberto; Grazia, L.; Lanciotti, R. High-pressure homogenization (HPH) has been proposed to be applied directly to lactic acid bacterial cells at sublethal levels to enhance some functional properties. As the principal target of HPH are the cell surface envelope structures, the aim of this work was to study the effect of a HPH treatment, applied at 50 MPa, on cell membrane stress responses of alreadyknown functional strains, isolated from Argentinean products. Specifically, the membrane fatty acid composition of cells before and after the sublethal treatment was investigated, and the results showed that plasma membranes, their level of unsaturation and their composition are involved in response mechanisms adopted by microbial cells when subjected to a sublethal HPH stress. In fact, the data obtained demonstrated that the treatment was able to modify the fatty acid profile of the different strains, although a uniform response was not observed. Further studies are necessary both to elucidate the role of each fatty acid in the cell response mechanisms and to clarify the changes in membrane compositions induced by HPH treatment also in relation to the applicative potential of this technique.

Longitudinal study of the species composition and spatio-temporal abundance of Anopheles Larvae in a Malaria risk area in Argentina Dantur Juri, Maria Julia; Galante, Guillermina Begoña; Zaidenberg, Mario; Almiron, Walter Ricardo; Claps, Guillermo Luis; Santana, Mirta Species composition and spatio-temporal abundance of Anopheles (Diptera: Culicidae) larvae and their relationship with environmental variables were studied in an endemic malarious area of northwestern Argentina, where Anopheles pseudopunctipennis is the main vector involved in malaria transmission. From Dec 2001 to Dec 2005, we performed monthly samplings of different aquatic larval habitats, such as puddles, irrigation canals, ponds and pools of Mountain Rivers. To determine the relationship among environmental variables and larval abundance, we used Poisson's regression analysis. We collected 5,079 larvae of which An. pseudopunctipennis was the most abundant species followed by Anopheles argyritarsis and Anopheles evansae. The density of Anopheles pseudopunctipennis larvae fluctuated between the end of spring until autumn, when malaria cases occur in the area. Concurrently, the larval densities of the other anophelinae species fluctuated throughout these climatic seasons. Poisson regression revealed that an increase of mean minimum temperature produced an increase in the abundance of An. pseudopunctipennis and An. argyritarsis. The mean maximum temperature and the water temperature greatly influenced the abundance of An. pseudopunctipennis, An. evansae and An. strodei. Increases of these temperature variables produced increases in abundance of these species. These factors should be taken into consideration when control measures for immature mosquitoes are implemented to reduce the number of larval habitats and the production of larvae, which may ultimately result in the elimination of malaria in this area.; La composición de las especies y la abundancia espacio-temporal de las larvas de Anopheles (Diptera: Culicidae) y su relación con las variables ambientales fueron estudiadas en un área endémica para malaria en el noroeste de Argentina, donde Anopheles pseudopunctipennis es el principal vector involucrado en la transmisión de la enfermedad. Entre diciembre de 2001 y diciembre de 2005 se realizaron muestreos mensuales de diferentes hábitats larvales acuáticos tales como charcos, canales de riego, estanques y ríos de montaña. Para determinar la relación entre las variables ambientales y la abundancia larval, se utilizaron análisis de regresión de Poisson. Se recolectaron 5.079 larvas, de las cuales Anopheles pseudopunctipennis fue la especie más abundante seguida de Anopheles argyritarsis y Anopheles evansae. Las larvas de An. pseudopunctipennis mostraron una fluctuación desde fines de primavera hasta el otoño, cuando los casos de malaria aparecen en el área. Mientras que las otras especies de larvas de anofelinos fluctuaron a lo largo de las estaciones climáticas. Las regresiones de Poisson revelaron que un aumento de la temperatura media mínima produce un incremento en la abundancia de An. pseudopunctipennis y de An. argyritarsis. La temperatura media máxima y la temperatura del agua influenciaron en gran medida la abundancia de An. pseudopunctipennis, An. evansae y An. strodei. Un incremento de estas variables produce un aumento en sus abundancias. Estos factores deben tenerse en cuenta al momento de implementar medidas de control sobre las formas inmaduras de estos mosquitos para reducir el número de hábitats larvales y la producción de larvas, lo cual podría al final resultar en la eliminación de la malaria en esta área.

Las «fábulas trágicas» que corrompen la sociedad: condena moral de la literatura popular en la prensa argentina a principios del siglo XX; The «tragic fables» that corrupt the society: moral condemnation of popular literature in the argentine press at the beginnings of the 20th century Risco, Ana Maria A comienzos del siglo XX, en la Argentina, la atención particular de la prensa a los folletines produce un discurso de rechazo a una «retórica popular» por lectores asociados a una intelectualidad ilustrada, comprometida en la construcción de un sentimiento universalista moralizante a través de la alta cultura. Este es el caso concreto del artículo Las fábulas trágicas, de Federico Quevedo Hijosa, publicado por el vespertino tucumano El Orden (01/03/1912). En el presente trabajo, analizamos su argumentación a fin de develar los presupuestos que intentan despojar la literatura de los elementos populares considerados «inmorales».; At the beginnings of the 20th century, in Argentine, the particular attention of the press to the newspaper serials produces a rejection discourse to a «popular rhetoric» by readers associated to an illustrated intelligentsia, compromised in building a universalistic moral sentiment through the high culture. This is the particular case of the Federico Quevedo Hijosa’s article Las fábulas trágicas, published in the journal El Orden of Tucumán (03/01/1912). On this paper, we analyse the presuppositions that reveal the intention to eliminate from the literature the popular elements considerate «immoral».

Una revisión de la Polarimetria y los efectos ionosféricos sobre los sistemas Sar, Insar y Palsar: requerimientos y métodos de corrección; Review of Polarimetric and ionospheric effects on Sar, Insar and Palsar systems: requirements and correction methods Rios, Victor Hugo Este estudio proporciona una actualización de las herramientas polarimétricas que se utilizan actualmente para la extracción óptima de la información a partir de imágenes de Radares de Apertura Sintética, SAR, de imágenes Interferométricas de SAR, InSAR e imágenes polarimétricas de SAR en la banda L, PALSAR. Los fundamentos de la teoría polarimétrica son discutidos en el contexto del radar de apertura sintética (SAR). Se revisa la calibración polarimétrica SAR, que es un tema importante para la extracción de información. Es considerada la extracción de información usando los parámetros de ondas dispersadas recibidas. Se proponen algunos esquemas de corrección ionosférica para las ondas transmitidas por el radar de apertura sintética (SAR) y para la interferometría SAR polarimétrica (PolInSAR) en el espacio. La variación temporal y espacial de la densidad de electrónica en la alta atmosfera afecta la propagación del pulso de radar dando lugar a distorsiones de la imagen. Se estima el Contenido Electrónico Total (CET) mediante la aplicación de la ecuación de Appleton-Hartree debido a distorsiones de enfoque, polarimetría e interferometría. Se propo-ne un estimador combinado que produce estimaciones diferenciales de CET. Se discute además el efecto de la estructura vertical de la ionosfera desde la fase interferométrica y se describen instrucciones importantes para la investigación futura.; This study provides an update of the polarimetric tools currently used for optimal extraction of information from polarimetric SAR (Synthetic Aperture Radar), INSAR (Interferometric Synthetic Aperture Radar) and PALSAR (Phase Array L-band Synthetic Aperture Radar) imagery. The fundamentals of polarimetric theory are discussed in the context of synthetic aperture radar (SAR). Polarimetric SAR calibration, which is important for the extraction of subject information, is reviewed. Extraction of information using the received scattered wave is considered. Some schemes for ionospheric correction to synthetic aperture radar (SAR) and the wave interferometry (PolInSAR) are proposed. Temporal and spatial variations of the electronic density in the upper atmosphere affect radar pulse propagation and, thereby, result in distortion of the image. Due to distortions of focus, polarimetry and interferometry, the Total Electron Content (TEC) has been estimated by applying the Appleton-Hartree equation. We propose a combined estimator that reliably estimates of TEC differentials. We also discuss the effect of the vertical structure of the ionosphere from the interferometric phase and outline important avenues for future research.

Repensando la teoría contemporánea sobre la gestión internacional de los estados subnacionales a través del caso de los gobiernos municipales de la provincia de Buenos Aires; Rethinking the contemporary theory of international management of subnational states through the case of municipal governments in the province of Buenos Aires Calvento, Mariana Los actores subnacionales han ampliado sus funciones tradicionales y han ampliado su ámbito de actuación hacia el plano internacional. Por ello, el presente artículo analiza la temática particular de la inserción internacional de las unidades subnacionales. Para este análisis el estudio se sustenta en la investigación del accionar internacional de los gobiernos municipales de tamaño intermedio de la provincia de Buenos Aires.El trabajo se concentra en casos insuficientemente analizados dentro de los actores subnacionales, los gobiernos municipales de tamaño intermedio de Argentina ya que, a diferencia de las grandes ciudades, éstos no tienen un lugar preestablecido en la arena internacional pero pueden generarlo y, a diferencia de las ciudades pequeñas, tienen mayores oportunidades y posibilidades de vincularse a nivel internacional.; In recent years, the territorial spaces have developed public policies to create or strengthen their international management. In that sense, this paper aims to address the particular issue of the international integration of subnational units probing and challenging traditional conceptions of the development of international policy on the part of subnational spaces. To do this, the study is based on research of international actions of municipal governments in the province of Buenos Aires.

Time course of systemic oxidative stress and inflammatory response induced by an acute exposure to Residual Oil Fly Ash Marchini, Timoteo Oscar; Magnani, Natalia Daniela; Paz, Mariela Laura; Vanasco, Virginia; Tasat, D.; Gonzalez Maglio, Daniel Horacio; Alvarez, Silvia; Evelson, Pablo Andres It is suggested that systemic oxidative stress and inflammation play a central role in the onset and progression of cardiovascular diseases associated with the exposure to particulate matter (PM). The aim of this work was to evaluate the time changes of systemic markers of oxidative stress and inflammation, after an acute exposure to Residual Oil Fly Ash (ROFA). Female Swiss mice were intranasally instilled with a ROFA suspension (1.0 mg/kg body weight) or saline solution, and plasma levels of oxidative damage markers [thiobarbituric acid reactive substances (TBARS) and protein carbonyls], antioxidant status [reduced (GSH) and oxidized (GSSG) glutathione, ascorbic acid levels, and superoxide dismutase (SOD) activity], cytokines levels, and intravascular leukocyte activation were evaluated after 1, 3 or 5 h of exposure. Oxidative damage to lipids and decreased GSH/GSSG ratio was observed in ROFA-exposed mice as early as 1 h. Afterwards, increased protein oxidation, decreased ascorbic acid content and SOD activity was found in this group at 3 h. The onset of an adaptive response was observed at 5 h after the ROFA exposure, as indicated by decreased TBARS plasma content and increased SOD activity. The observed increase in oxidative damage to plasma macromolecules, together with systemic antioxidants depletion, may be a consequence of a systemic inflammatory response triggered by the ROFA exposure, since increased TNF-α and IL-6 plasma levels and polymorphonuclear leukocytes activation was found at every evaluated time point. These findings contribute to the understanding of the increase in cardiovascular morbidity and mortality, in association with environmental PM inhalation.

Host-Specific Enzyme-Substrate Interactions in SPM-1 Metallo-beta-Lactamase are Modulated by Second Sphere Residues Gonzalez, Lisandro Javier; Moreno, Diego Martin; Bonomo, Robert A.; Vila, Alejandro Jose Pseudomonas aeruginosa is one of the most virulent and resistant non-fermenting Gram-negative pathogens in the clinic. Unfortunately, P. aeruginosa has acquired genes encoding metallo-beta-lactamases (MBLs), enzymes able to hydrolyze most beta-lactam antibiotics. SPM-1 is an MBL produced only by P. aeruginosa, while other MBLs are found in different bacteria. Despite similar active sites, the resistance profile of MBLs towards beta-lactams changes from one enzyme to the other. SPM-1 is unique among pathogen-associated MBLs in that in that it contains "atypical" second sphere residues (S84, G121). Codon randomization on these positions and further selection of resistance-conferring mutants was performed. MICs, periplasmic enzymatic activity, Zn(II) requirements, and protein stability was assessed. Our results indicated that identity of second sphere residues modulates the substrate preferences and the resistance profile of SPM-1 expressed in P. aeruginosa. The second sphere residues found in wild type SPM-1 give rise to a substrate selectivity that is observed only in the periplasmic environment. These residues also allow SPM-1 to confer resistance in P. aeruginosa under Zn(II)-limiting conditions, such as those expected under infection. By optimizing the catalytic efficiency towards beta-lactam antibiotics, the enzyme stability and the Zn(II) binding features, molecular evolution meets the specific needs of a pathogenic bacterial host by means of substitutions outside the active site.

Study of hydrogen adsorption properties on MCM-41 mesoporous materials modified with nickel Carraro, Paola María; Elías, Verónica Rita; Garcia Blanco, Andres Alberto; Sapag, Manuel Karim; Eimer, Griselda Alejandra; Oliva, Marcos Iván MCM-41 samples were modified with different Ni loadings by wet impregnation method and characterized by XRD, ICP, EPMA-EDS, N2 adsorptionedesorption and hydrogen adsorption at 77 K at high and low pressure conditions. The hydrogen adsorption studies for the MCM-41 host and the impregnated samples showed that small amounts of Ni ions in MCM-41 improved the hydrogen storage capacity by spillover effect.