Determinación de nitrógeno inorgánico y fosfatos a distintas profundidades de suelo bajo pilas de abonos; Determination of Inorganic Nitrogen and Phosphates at Different Soil Depths Beneath Manure Piles
Ferrari, Javier Luis; Martinez Carretero, Eduardo Enrique; Cremona, Victoria; Mazzarino, Maria Julia
En la región Andino-patagónica frecuentemente la reposición de nutrientes para diferentes cultivos se lleva a cabo mediante el uso de estiércoles mezclados con viruta, comúnmente denominados abonos. Los mismos son acumulados en pilas de 1,5-2 m de altura. Al permanecer durante un período de tiempo al aire libre puede producirse un compostaje parcial, lo cual sería beneficioso. El compostaje es un proceso biooxidativo que involucra un sustrato orgánico, una etapa termofílica que debe alcanzar los 55ºC y una etapa de maduración. Si los abonos permanecen a la intemperie los nutrientes pueden ser transportados por el agua de percolación (particularmente en los meses de invierno de mayor precipitación), perdiéndose del suelo. Con el objetivo de determinar si ocurre un movimiento de fosforó extractable en NaHCO3 0.5M (P-Ol de fósforo Olsen) y nitrógeno inorgánico (Nin de nitrógeno inorgánico, amonio más nitratos) bajo pilas de abono, se tomaron muestras compuestas de suelos de tres bloques a distintas profundidades en un establecimiento cercano a la localidad del Bolsón. Se estudió también la relación entre P-Ol (índice agronómico) y fósforo extractable en 0,01M de CaCl2 (índice ambiental). Se tomaron las temperaturas de las pilas de abono en distintas estaciones del año. Para Nin se observó una alta dispersión en los datos y valores promedio excesivamente altos hasta 200 cm de profundidad. Los valores promedio (de tres bloques) encontrados para P exceden el umbral límite de 60 mg kg-1 P-Ol solo en la primera fecha de muestreo, aunque valores puntuales por bloque llegaron a 52 mg kg-1 a una profundidad de 40-60 cm. Se encontró una regresión lineal estadísticamente significativa entre P-Ol y P-CaCl2 en suelos y un umbral entre 50/60 mg kg-1 P-Ol similar al observado en la bibliografía. Se encontraron valores muy altos para ambas variables en los abonos. Es recomendable proteger las pilas de abono de las lluvias en los meses de invierno.; In the Andean – Patagonian region, nutrient supply for different crops is frequently made using wood chips mixed with manure. These materials are accumulated in piles of 1.5 – 2 m height. As the piles remain for a period of time outdoors, a partial composting may occur, which would be beneficial. Composting is a biooxidative process, involving an organic substrate, a thermophilic phase that must be reached (55ºC) and a maturity stage. If the manure piles remain outdoors, nutrients can also be transported by water and lost from the soil through percolation (particulary during winter months of higher precipitations). With the objective of studying if extractable phosphorus in NaHCO3 0.5M (P-Ol of phosphorus Olsen) and inorganic nitrogen (Nin;ammonium plus nitrates) move beneath the piles of manure, composites soil samples were taken from three blocks at different depths in a farm near the town of El Bolsón. The relationship between P-Ol (agronomic threshold) and extractable P in 0.01 M CaCl2 (environmental threshold) was also studied. Manure temperatures were taken in different seasons. Nin showed a high data dispersion and excessively high mean values up to the 200 cm depth. Average values (of three blocks) found for P exceeded the threshold limit of 60 mg kg-1 P-Ol only on the first sampling date in the 0-20cm depth, although individual data for each block reached 52 mg kg-1 in the 40-60 cm depth. A statistically significant linear regression between P-Ol and P-CaCl2 in soils was obtained, and a threshold near 50/60 mg kg-1, similar to the values reported in the literature. High values for both parameters were found in manures. It is advisable to protect piles of manure from rainfall in winter months.
Lectotipificaciones en Ophryosporus (Asteraceae, Eupatorieae, Critoniinae); Lectotypifications in Ophryosporus (Asteraceae, Eupatorieae, Critoniinae)
Plos, Anabela; Sancho, Gisela
Se tipifican 10 nombres pertenecientes a especies de Ophryosporus, como una contribución nomenclatural a una próxima revisión taxonómica del género.; Lectotypifications in Ophryosporus (Asteraceae, Eupatorieae, Critoniinae). Typification is
provided for 10 names of Ophryosporus as a nomenclatural contribution to a forthcoming taxonomic revision of the genus.
El deterioro laboral de las poblaciones de Catamarca y Tucumán (1980-2002)
Osatinsky, Ariel
A comienzos del siglo XXI los problemas de empleo afectaban a un porcentaje elevado de la población económicamente activa (PEA) de Catamarca y de Tucumán. Tanto la desocupación, la subocupación como el empleo informal habían tenido un pronunciado incremento en las décadas de 1980 y 1990 en ambas provincias. Sin embargo, en Tucumán el deterioro laboral fue mayor. Aquellos fueron años en los que las transformaciones económicas tuvieron características marcadamente regresivas. Estos cambios económicos no se produjeron en los mismos momentos, ni de forma similar, ni con la misma intensidad en Catamarca y Tucumán. En ese sentido, el objetivo del artículo es analizar la evolución y características de los problemas de empleo que afectaron a las PEA de ambas provincias entre 1980 y el 2002, vinculando éstos con las transformaciones económicas mencionadas. A través del análisis de indicadores laborales y económicos de relevancia, se pudo constatar que el mayor deterioro laboral que afectó a la población tucumana estuvo vinculado a las transformaciones productivas más negativas que atravesó su economía. Por su parte Catamarca, que atravesó dificultades económicas de menor gravedad, tenía una mayor presencia del Estado, que actuaba como atenuante ante los crecientes problemas de empleo del período.; By the beginnings of the XXI century, problems in the job market affected a high percentage of the Economically Active Population –EAP– in Catamarca and Tucuman. During the 1980 and 1990 decades, all unemployment, underemployment and informal employment had seen a deep increase in both provinces. However, the deterioration in the job market was worse in Tucuman. During those years, markedly regressive economic transformations took place. These economic changes did not take place at the same exact moments, or in similar way, or with the same intensity in Catamarca and Tucuman. The purpose of this article is to analyze the evolution and characteristics of the employment problems that affected both provinces' EAP between 1980 and 2002, linking them to the aforementioned economic transformations. By analyzing relevant job-market and economic indicators, we were able to assess that the largest deterioration in the job market in Tucuman was linked to the most negative productive transformations suffered by its economy. In Catamarca, which suffered less severe economic difficulties, there was a more important presence of the State, which acted as a mitigating factor in front of the growing employment problems.
Tendencias innovadoras en las prácticas psiquiátricas: Argentina, 1960-1970; Innovative practices in Psychiatry: Argentina, 1960-1970; Tendências inovadoras nas práticas psiquiátricas: Argentina, 1960-1970
Golcman, Aida Alejandra
El trabajo analiza prácticas psiquiátricas innovadoras que se llevaron a cabo en Argentina durante las décadas del sesenta y setenta, a partir del estudio del Hospital José Esteves en la provincia de Buenos Aires. Objetivo: presentar la convivencia de paradigmas diferentes y en tensión referentes a la salud mental en una misma institución, con las complejidades que este escenario apareja. Metodología: para este estudio se utilizaron como fuente principal las historias clínicas de las pacientes admitidas en el Hospital entre 1960 y 1979, las que fueron cruzadas con publicaciones de diarios y revistas de la época. Resultados: del análisis se desprende que el contexto político de la época ?de dictadura militar, de anulación de expresión política y persecución ideológica? influyó en el desarrollo de las experiencias psiquiátricas innovadoras. De este modo, se detectaron situaciones de antisemitismo y persecución ideológica a los trabajadores de la salud que participaron de estos proyectos, al tiempo que se confundieron conceptos y propuestas terapéuticas con ideas políticas ?comunistas?. Conclusiones: a pesar de que la introducción de concepciones y prácticas diferentes sobre la salud mental generó cierta resistencia entre los psiquiatras más ortodoxos, la presencia de paradigmas distintos muestra un plan, tanto político como profesional, para transformar la Psiquiatría y la internación en Argentina; The paper analyzes innovative psychiatric practices that took place in Argentina during the sixties and seventies at the Hospital Jose Esteves in the province of Buenos Aires. Objective: To present the coexistence of different paradigms related to mental health in the same institution and to analyze the complexities generated by this scenario. Methodology: This study uses primary sources in the form of medical records of patients admitted to the hospital between 1960 and 1979. The medical records were cross-referenced with publications of newspapers and magazines of the time. Results: The analysis shows that the political environment during the era of military dictatorship —characterized by ideological persecution and the inhibition of political expression — influenced the development of innovative psychiatric practices. At the same time, instances of anti-Semitism and ideological persecution among health workers affected therapeutic approaches. Conclusions: While the introduction of innovative practices in mental health led to some resistance among the more orthodox psychiatrists, the presence of different paradigms shows a plan, both political and professional, to transform psychiatry and admission policy in Argentina.; O trabalho analisa práticas psiquiátricas inovadoras que se levaram a cabo na Argentina durante as décadas sessenta e setenta, a partir do estudo do Hospital José Esteves na província de Buenos Aires. Objetivo:apresentar a convivência de paradigmas diferentes e em tensão referentes à saúde mental em uma mesma instituição, com as complexidades que este cenário aparelha. Metodologia: para este estudo utilizou-se como fonte principal as histórias clínicas das pacientes admitidas no Hospital entre 1960 e 1979, as quais foram comparadas com publicações de jornais e revistas da época. Resultados: da análise se desprende que o contexto político da época (de ditadura militar, de anulação de expressão política e persecução ideológica) influiu no desenvolvimento das experiências psiquiátricas inovadoras. Deste modo, detectaram-se situações de anti-semitismo e persecução ideológica aos trabalhadores da saúde que participaram destes projetos, ao tempo que se confundiram conceitos e propostas terapêuticas com ideias políticas “comunistas”. Conclusões: a pesar que a introdução de concepções e práticas diferentes sobre a saúde mental gerou certa resistência entre os psiquiatras mais ortodoxos, a presencia de paradigmas distintos mostra um plano, tanto político quanto Professional, para transformar a psiquiatria e a internação na Argentina.
Los avatares del psiquismo en las ciencias sociales
Golcman, Aida Alejandra
Este trabajo articula ciertos conceptos presentados por Norbert Elias con nociones psicoanalíticas que permiten profundizar las ideas del autor. Para desarrollar esta relación, elegimos principalmente dos temáticas: por un lado la cuestión de la psicogénesis en el proceso de civilización de la humanidad y por otro, la preocupación por el trauma, el hecho no resuelto que retorna, y su mirada vinculada con el nazismo y la actualidad de Alemania. Con las cuestiones desarrolladas, Elias hace un corte transversal de ciertas estructuras y hechos sociales; además de permitir pensarlas desde la sociología, la historia y la psicología, nos advierte sobre los peligros de las concepciones estáticas de la sociedad; así plantea la necesidad de entender los procesos, con sus avances y retrocesos en el largo plazo.; This work uses psychoanalytic ideas to expand upon concepts presented by Norbert Elias. We focus on two main themes: (1) the role of psychogenesis in the process of civilization, and (2) trauma and Elias' perspectives on Nazism and modern Germany. Using these topics and drawing on Sociology, History, and Psychology, the author examines structures and social events that remind readers of the dangers of static conceptions of society and the need to understand societal processes in the long term.
Soil productivity from the sandy pampas region under the present agricultural conditions
Diaz Zorita, Martin
During the last decade, major changes in the organization, extension and intensification of the agricultural systems from the sandy pampas region are observed. Crop production is mostly performed under continuous zero tillage and with the application of fertilizers. In this region, strong relationships between crop yields and soil properties, mostly related to water and nutrient storage, have been described. The purpose of this presentation is to discuss, supported by specific local long-term field trials, about several of the changes in the productivity of the soils of the region under the present management practices. Soil organic matter levels decrease under continuous tillage practices after systems with pastures. But, the application of zero tillage practices contributed to maintain the original soil productivity properties. Production systems established on degraded soils frequently show less water use efficiency, mainly when are cropped with maize (Zea mays L.). The establishment of continuous fertilization programs based on the sufficiency for low mobility nutrients (e.g. Phosphorus) shows reduction in the soil extractable levels of the nutrient and lower mean crop production compared with maintenance fertilization programs. The use of winter cover crops in soybean [Glycine max (L.) Merrill] monoculture enhances physical soil properties without benefits on crop yields. The crop and soil management practices widely performed during this period have contributed to the soil conservation and to the water use efficiency. However, the application of sufficiency fertilization programs could conduct to the reduction in the levels of soil extractable nutrients and in crop productivity. The present agricultural land use in the region requires to intensify in the use of indexes for the diagnosis of soils productivity independently of the actual relationships with today`s yields. The delimitation of homogeneous areas for the application of efficient soil management practices is needed for the conservation and enhancement of soils productivity capability.
Mineral chemistry and geothermometry using relict primary minerals in the La Cocha ultramafic body: A slice of the upper mantle in the Sierra Chica of Córdoba, Sierras Pampeanas, Argentina
Anzil, Patricia Andrea; Guereschi, Alina Beatriz; Martino, Roberto Donato
The La Cocha ultramafic body, in the Sierra Chica of Córdoba (Sierras Pampeanas, Argentina), is formed by serpentinized spinel harzburgites, with lenses of spinel pyroxenites and hornblendites. The associated metamorphic rocks are garnet sillimanite gneisses, intercalated with tabular bodies of pyroxene amphibolites and forsterite marbles.Mineral chemistry of relict primary phases (olivine, orthopyroxene and spinel) from samples of the spinel harzburgites and pyroxenites was determined, and several geothermometers were applied to estimate the temperature conditions under which these rocks may have been equilibrated.In the spinel harzburgites, the primary spinel is Al-chromite [Cr# = Cr/(Cr + Al) = 0.48-0.57], which is replaced by ferrichromite and chlinoclore by metamorphism. Orthopyroxene is enstatite (En92) and olivine is classified as forsterite (Fo92); this last one shows a homogeneous and constant composition along the ultramafic body. Using geothermometric calibrations of the pair olivine-spinel, the highest temperature of 1157 °C would correspond to the primary conditions of formation of the harzburgites.The spinel pyroxenites show a mineral composition defined by orthopyroxene (En85, enstatite), olivine (Fo86, chrysolite), spinel (s. s.) and magnetite. Serpentine and clinochlore were produced by metamorphism. Spinel has high concentrations in Al and very low in Cr, and is classified as spinel sensu stricto; magnetite replacement was produced by metamorphism. Orthopyroxene and olivine are depleted in MgO regarding these minerals in the harzburgites. Temperatures of 785-734 °C calculated using geothermometers with orthopyroxene are interpreted to be produced by metamorphism in amphibolite to granulite facies conditions.Cumular textures were not observed in outcrops and thin sections of the studied rocks. The narrow composicional range and high forsterite content in olivine, the high Cr# in spinel, and the low concentrations of Ni and Cr in whole rock analyses indicate a mantle residual origin for these peridotites, which would exclude a cumular origin.The association of peridotites with mafic bodies formed in an N-type MORB environment and a relict mantle fabric showed by the elongated crystals/aggregates of olivine (preserved in pseudomorphic replacements), indicating a high temperature flow, allow to interpret the La Cocha ultramafic body as a slice of oceanic mantle, belonging to basal tectonites of an ophiolite complex. This body shows similar petrological, geochemical and structural features than the other ultramafic bodies in the Sierras de Córdoba, therefore the origin proposed here could be applied to the other bodies.
Dinámicas del sector agropecuario argentino en el siglo XXI: La distribución del ingreso en regiones pampeanas y extrapampeanas
Mario, Agustin Angel; Vidosa, Regina
En este trabajo se analizan una serie de aspectos que resultan centrales para comprender la situación de los trabajadores en el sector agropecuario. En primer lugar, se contrapone la evolución del producto del sector con la capacidad que el mismo posee para generar puestos de trabajo. Luego, se da cuenta de las condiciones de empleo que se verifican en el sector agropecuario, poniendo especial énfasis en el estudio del grado de informalidad y los niveles salariales. Se compara, a continuación, la distribución primaria del ingreso del sector con la de la economía nacional en su conjunto. Este análisis distributivo se complementa con dos estudios de caso que intentan poner de manifiesto las implicancias que poseen distintos cultivos llevados a cabo en diferentes regiones. El estudio muestra que el salario medio del sector agropecuario sigue estando muy por debajo de la remuneración promedio de la economía y que, además, la participación de los salarios en el valor agregado del sector se ha reducido desde la salida de la convertibilidad aún en un contexto de aumento del salario medio sectorial. Finalmente, con base en el análisis de los casos mencionados, se asocia la distribución del ingreso con los distintos cultivos y las regiones donde estos se llevan a cabo. Al respecto, se discute el rol de las ganancias individuales como guía orientadora del uso de la tierra cultivable.; This paper discusses a number of issues that are central to understanding the situation of workers in the agricultural sector. First, the evolution of the sectorial product is contrasted with the capacity that it posseses to generate jobs. Then, the working conditions verified in the agricultural sector are described, with particular emphasis on the study of the degree of informality and the wage levels. It then compares the primary distribution of income of the sector to that of the national economy as a whole. This distributional analysis is complemented by two case studies that attempt to show the implications that distinct crops carried out in different regions have. The study shows that the average wage in the agricultural sector remains well below the average wage in the economy and, in addition, the share of wages in the sectorial value added has declined since the end of the convertibility regime, even in a context of an increasing average wage in the sector. Finally, based on the analysis of the above cases, income distribution is associated to the different crops and the regions where they are carried out. In this regard, the role of individual earnings as a guide to the use of arable land is discussed.
Phosphorylation of Mitogen-Activated Protein Kinases Contributes to Interferon γ Production in Response to Mycobacterium tuberculosis
Pasquinelli, Virginia; Rovetta, Ana Inés; Alvarez, Ivana Belén; Jurado, Javier Oscar; Musella, Rosa María; Palmero, Domingo J.; Malbrán, Alejandro; Samten, Buka; Barnes, Peter F.; García, Verónica Edith
Immune control of Mycobacterium tuberculosis depends on interferon γ (IFN-γ)–producing CD4+ lymphocytes. Previous studies have shown that T cells from patients with tuberculosis produce less IFN-γ, compared with healthy donors, in response to mycobacterial antigens, although IFN-γ responses to mitogens are preserved. In this work, we found that M. tuberculosis–induced IFN-γ production by human T cells correlated with phosphorylation of the mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK), and p38. Moreover, the majority of IFN-γ–producing T cells expressed signaling lymphocyte activation molecule (SLAM), and SLAM activation further increased ERK phosphorylation. Interestingly, patients with tuberculosis had delayed activation of ERK and p38, and this was most marked in patients with the poorest IFN-γ responses (ie, low responders). Besides, SLAM signaling failed to phosphorylate ERK in low responders. Our findings suggest that activation of p38 and ERK, in part through SLAM, mediates T-cell IFN-γ production in response to M. tuberculosis, a pathway that is defective in patients with tuberculosis.
Instituciones, investigadores y comunidades indígenas chaqueñas; Institutions, researchers and Chaquean indigenous communities: triangulation of interests around State photographic archives
Giordano, Mariana Lilian
La constitución de fondos documentales fotográficos que surgieron de intereses estatales desde fines del siglo XIX se presenta como una de las tantas modalidades de perpetuación de la captura de los “otros” indígenas, que responde a su vez a las maneras de definir la ciencia, de afirmar el poder del Estado sobre los “otros” y de constituir identidades nacionales y memorias recortadas. Este artículo se introduce en el mundo de los fondos fotográficos de indígenas del Gran Chaco teniendo en cuenta que los mismos no son construcciones de existencia neutra e invariable, sino que tienen una “vida” que refleja los intereses de diversos agentes que lo guardan y/o que pretenden utilizarlos, difundirlos o poseerlos. A la vez, indaga en el rol que las fotografías desempeñan en la construcción de memorias en las comunidades indígenas chaqueñas actuales y la legitimidad que éstas poseen en las demandas por las mismas, poniéndose en discusión la cuestión de la “propiedad” de las imágenes. Tales reflexiones se consideran en torno a los conceptos de hegemonía y colonialidad del poder. De tal forma, planteamos una mirada triangular hacia las instituciones –en particular las estatalesque conservan las imágenes, hacia nuestro propio interés y rol de investigador sobre las fotos en estudio y hacia las intenciones y demandas de las comunidades indígenas chaqueñas actuales respecto de estos fondos.; The constitution of documentary photography from states’ interests comes from the late nineteenth century and it is presented as one of the many modalities of perpetuating the capture of the “other” indigenous. That situation responds to the different ways of defining science, to assert state power over “others” and to establish national identities and biased memories. This article introduces into the world of photographic collections of indigenous of the Gran Chaco taking into account that they are not neutral constructions of unchanging existence; eventhough, they have a “life” that reflects the interests of different stakeholders who keep them or intend to use, spread or possess them. Besides, we analyze the role that these photographs have in building memories within Chaco indigenous communities today. Therefore, we also call into question the copyright or “property” of images. These reflections are considered around the concepts of hegemony and coloniality of power. Thus, there is a triangular look towards the institutions, -including state ones- that preserved the images, to our own interest and our role as researchers on photos and into the intentions and demands of Chaco indigenous communities.
Biological traits and growth patterns of pejerrey Odontesthes argentinensis
Llompart, Facundo Manuel; Colautti, Dario César; Maiztegui, Tomás; Cruz Jiménez, Adriana Milena; Baigún, Claudio Rafael M.
This study assesses for the first time the relationship between annual cycles of different biological indices with growth patterns of a marine pejerrey Odontesthes argentinensis population near its southern-distribution boundary in North Patagonia. The reproductive period is between September and November evidenced by an increase in the gonado-somatic index with a peak in October corresponding to spawning. The reproductive cycle was also coupled with metabolic processes related to energy allocation as shown by changes in the hepato-somatic index and body condition. Total length (LT) at maturity was 270 for females and 282 mm for males, whereas fecundity was estimated at mean ± s.d. = 9380 ± 1797 mature oocytes. Based on the marginal increment analysis, most of the scales showed a maximum value during summer, with a sharp decline thereafter during autumn and winter, indicating that scale rings are formed during the latter period and only once a year. Growth fitted by the von Bertalanffy model for both males and females did not show significant differences and showed a rapid growth during the first 2 years. The shorter reproductive period compared with that of the northern O. argentinensis populations inhabiting tropical and subtropical areas was interpreted as an adjustment to temperate environmental conditions. The larger maximum LT and LT at first maturity are in agreement with the counter-gradient hypothesis and could be related to the selective effects of low temperature and a shorter growing season. This latitude dependency argues strongly against the application of the same fishing regulations for different O. argentinensis populations as a whole and reinforces the need to assess basic biological features at a population scale to promote local sustainable fisheries management.
The Chacoan peccary, Catagonus wagneri (Mammalia, Tayassuidae), in the late Pleistocene (northern Uruguay, South America): paleoecological and paleobiogeographic considerations
Gasparini, Germán Mariano; Ubilla, Martin; Tonni, Eduardo Pedro
Catagonus wagneri has the most restricted geographical distribution among extant Tayassuidae and inhabited semi-arid thorny forests of dry Chaco in Paraguay, Bolivia and Argentina. Until now, C. wagneri has only been recorded in archaeological, pre-Hispanic deposits from the Santiago del Estero Province, Argentina. A new partially complete skull from the Sopas Formation (Late Pleistocene; Uruguay) is identified as C. wagneri. This is the only fossil record of the species which extends its biochron until the late Pleistocene, and the first one substantially far from its current range; the first fossil record of the species in Uruguay; the most complete fossil material of the species; and it provides relevant ecological and climatic information. According to the ecological and climatic available information of C. wagneri, the presence of this mammal in the late Pleistocene of northern Uruguay indicates a warm climate and arid to semi-arid environments. Even though not associated with the fossil remains of C. wagneri, some mammals included in the sedimentary levels of the Sopas Formation also suggest arid to semi-arid environments. Climatic changes, in particular in the late Pleistocene and Holocene, could be invoked to explain modifications of its geographic range.
Cryptic homoeology analysis in species and hybrids of genus Zea
Molina, María del Carmen; López, C. G.; Staltari, Silvana Andrea; Chorzempa, Silvia Elena; Moreno Ferrero, V.
Cryptic intergenomic pairing of genus Zea was induced by the use of a diluted colchicine solution in order to elucidate the phylogenetic relations and differentiation of the homoeologous genomes. Results indicate that in species and hybrids with 2n = 20, there was chromosome pairing between the homoeologous A and B genomes with a maximum of 5IV, with the exception of Zea diploperennis and their interspecific hybrids where cryptic homoeologous chromosome pairing was not induced. In almost all 2n = 30 hybrids, observed cryptic pairing increased to a maximum of 10III although Z. mays × Z. mays with 2n = 30 did not show significant differences between treated and untreated materials. Pairing was also observed in species and hybrids with 2n = 40, in which a maximum of 10IV was observed, with the exception of Z. mays with 2n = 40 where treated and untreated cells did not differ significantly.
46 meganuclease i-SceI enhances stable transgene integration in cultured bovine fetal fibroblasts
Ortega, Nicolás Matías; Benitez, S. B.; Barrionuevo, Blanca Elizabeth; Olmos Nicotra, Maria Florencia; Alessio, Ana Paula; Fili, Alejandro; Forcato, Diego Oscar; Stice, S. L.; Bosch, Pablo
Production of genetically modified large animals through somatic cell nuclear transfer (SCNT) requires genetic manipulation of cultured cells, which are subsequently used as nuclear donors to generate a transgenic animal. Stable transgene integration into the donor cell genome is an inefficient process that involves integration of transgenes in randomly occurring DNA double-strand breaks. Therefore, our objective was to evaluate transient and stable transfection in cultured bovine fetal fibroblasts (BFF) using a transgenic strategy based on the simultaneous presence of a meganuclease (I-SceI) and a transgene flanked by restriction sites for I-SceI. Bovine fetal fibroblasts (2.63 × 104 cells cm–2 in 24-well plates) were co-transfected with a plasmid vector (pBSII-I-SceI-ZsGreen1-Neo) carrying expression cassettes for ZsGreen1 (fluorescent protein) and neomycin resistance flanked by restriction sites for I-SceI along with an expression plasmid for I-SceI (pCBASce). As controls, BFF were co-transfected with pBSII-I-SceI-ZsGreen1-Neo plus a plasmid that lacks the I-SceI expression cassette (pCBA). Lipofectamine 2000 (Invitrogen) was used as the transfection reagent as per manufacturer’s instructions. Two different relationships of vector pBSII-I-SceI-ZsGreen1-Neo to pCBASce or pCBA (control) were tested: 1 : 1 and 1 : 3 (total amount of plasmid DNA per well was 500 ng). Transient transfection was evaluated by flow cytometry and reported as percentage of green fluorescent cells 72 h post-co-transfection. Stable integration of transgene sequences was assessed 21 days after co-transfection by determining the number of fluorescent cell colonies (FCC) that developed in selective media (DMEM + 250 µg mL–1 of G418). Data were analyzed by ANOVA and Tukey test and expressed as mean ± standard error of the mean. Flow cytometric analysis at 72 h post-transfection showed no statistical differences between the proportions of fluorescent cells in cultures co-transfected with pCBASce compared with those transfected with the control plasmid. The number of FCC developed from cultures co-transfected with pBSII-I-SceI-ZsGreen1-Neo plus pCBASce at a 1 : 1 ratio was 6.4-fold higher compared with those observed in the control group at the same ratio (8.00 ± 2.16 v. 1.25 ± 0.62 colonies; P < 0.05). However, there was no difference in the number of FCC formed at a plasmid ratio of 1 : 3 between the treatment (3.75 ± 1.03 colonies) and the control (2.70 ± 1.35 colonies; P > 0.05). Several transgenic BFF cell lines were generated by subculturing individual colonies. Polymerase chain reaction and Southern blotting confirmed that antibiotic-resistant and phenotypically positive colonies had integrated the ZsGreen1 transgene. Western blot analysis using an anti-HA antibody revealed a band of the expected size (30 kDa) in cells transfected with pCBASce. We conclude that I-SceI transgenesis significantly increases the functional integration of plasmid DNA into the bovine fibroblast genome as has been reported in embryos of other vertebrates, up to now by unknown mechanisms. This transgenic strategy should facilitate stable transfection of bovine fibroblasts to generate genetically modified animals though SCNT.
331 optimization of branched 25 kDa polyethylenimine for efficient gene delivery in bovine fetal fibroblasts
Forcato, Diego Oscar; Olmos Nicotra, Maria Florencia; Ortega, Nicolás Matías; Alessio, Ana Paula; Fili, Alejandro; Rodriguez, Natalia Evelin; Bosch, Pablo
Cost-effective, highly efficient, and noncytotoxic transfection of bovine fetal fibroblasts (BFF) has proven difficult to achieve by regular chemical and physical methods. The aims of this study were to evaluate transient transfection efficiency and toxicity of commercially available branched 25 kDa polyethylenimine (25 kDa PEI, Sigma-Aldrich, St. Louis, MO, USA) and to optimize the transfection conditions leading to high percentages of PEI-transfected fibroblasts with minimum cytotoxic effects. Bovine fetal fibroblast (BFF) cells were seeded a day before transfection in 24-well plates at a density of 3 × 104 cells per well in DMEM with antibiotics and 10% SFB. When 70 to 90% confluence was reached, cells were washed with PBS and incubated in DMEM without antibiotics or SFB. For the transfection-mix preparation, increasing amounts of plasmidic DNA (pZsGreen1; 2 to 6 µg) were added to 50 µL of DMEM without antibiotics or SFB, incubated for 5 min at room temperature, and complexed with 0.5 to 4 µg of PEI (from 1 mg mL–1 solution) in 50 µL of PBS for 10 min. This transfection mix was added to the cell cultures and, 2 h later, 500 µL of DMEM with antibiotics and 10% SFB was added to each well. Detection of green fluorescent protein (GFP) expression by flow cytometry (reported as percentage of green fluorescent cells) was performed 48 h after transfection. Results were analysed by ANOVA and Tukey test and expressed as mean ± SEM (P < 0.05). We found no significant difference between the percentage of GFP-positive cells transfected with 1 or 2 µg of 25 kDa PEI at 2 µg of DNA/well (15.2 ± 1.3 v. 16.9 ± 0.9%, respectively; P > 0.05), whereas cells transfected with 1 or 2 µg of low-molecular-weight PEI (2 kDa) showed extremely low transfection efficiencies. Increasing the DNA load up to 6 µg significantly enhanced cell transfection (3.5- and 6-fold comparing 2 µg v. 4 µg and 6 µg of DNA, respectively; P < 0.05) at 1 and 2 µg of 25 kDa PEI/well. In order to evaluate the cytotoxic effect of PEI, cell viability was determined using the MTT assay in 96-well plates (cells/well), with each condition scaled down to replicate the effect of 2 kDa or 25 kDa PEI in a 24-well plate. The MTT results (expressed as % of the control) indicated that PEI became cytotoxic at concentrations equivalent to 2 and 4 µg/well (54.7 ± 3.4 and 18.5 ± 5.7, respectively), whereas 1 µg/well produced a slight detrimental effect on cell viability (90.0 ± 2.6). No evidence of cytotoxicity was observed when the BFF were incubated with 0.5 µg/well of 25 kDa PEI and 1 or 2 µg/well of 2 kDa PEI. To study if a combination of low- and high-molecular-weight PEI could improve transfection efficiency and reduce toxicity, we tested a mixture (1 : 1) of 2 kDa and 25 kDa PEI. Even though the 1 : 1 mixture was less cytotoxic, the efficiency of gene delivery was not improved. We conclude that, under our experimental conditions, the highest percentage of GFP-expressing cells with good viability was obtained when 1 µg of 25 kDa PEI was added per well. Therefore, branched 25 kDa PEI transfection represents an efficient, simple, and cost-effective alternative for gene delivery in bovine fibroblast cells in culture.
Impact of structural and textural membrane properties on lemon juice clarification
Chornomaz, Patricia Mariana; Pagliero, Cecilia Liliana; Marchese, Jose; Ochoa, Nelio Ariel
Lemon juice was clarified using membranes with different structural and textural properties. Membranes were prepared from 0, 5, 7 and 10 wt.% of PVP in PVDF and they were structurally and functionally characterized. Results indicated that the addition of PVP produced both structural and surface textural changes in the membranes. These textural changes resulted in an increase of apparent hydrophobicity in the membranes prepared from 5 and 7% of PVP in the casting solution. Besides, the presence of residual PVP in the membrane favors hesperidin adsorption enhancing its retention. Analysis of the clarified juice indicated that the membrane prepared with 5% of PVP possessed the highest efficiency, combining high permeate flux and high juice quality.
Eficaz selección de espermatozoides bovinos criopreservados usando filtración por columnas de lana de vidrio; Efficient cryopreserved bovine sperm selection using glass wool filtration
Vazquez, Monica Hebe; Marin Briggiler, Clara Isabel; Cetica, Pablo Daniel; Dalvit, Gabriel Carlos; Caballero, J. N.; Arzondo, Maria Matilde
La criopreservación del semen es ampliamente utilizada en el manejo reproductivo bovino y permite la distribución y comercialización del material genético de esta especie. Sin embargo, los protocolos de congelación/descongelación afectan negativamente la calidad espermática, originando una alta proporción (más del 50%) de espermatozoides muertos y criocapacitados, no aptos para la fecundación. Para obtener espermatozoides funcionales es necesario realizar procedimientos de selección espermática. Recientemente hemos publicado un trabajo en la revista Theriogenology (2012; 78:201-209) que describe el uso de la filtración por columnas de lana de vidrio para la selección de espermatozoides funcionales a partir de semen bovino previamente congelado. El método es rápido, sencillo y económico, y permite seleccionar un alto porcentaje de espermatozoides vivos (94±3%), con motilidad progresiva (89±4%), no capacitados (80±10%), con el acrosoma intacto (98±1%) y que presentan alta capacidad de fecundar ovocitos in vitro. La técnica de filtración permite obtener un rendimiento del 67±19 %, ~4 veces mayor que el del método de Swim up. En conclusión, la filtración por columnas de lana de vidrio es una alternativa válida para las biotecnologías reproductivas bovinas, así como para otros animales domésticos y de granja y para especies en peligro de extinción.; Frozen bull semen is worldwide distributed and utilized in several assisted reproductive technologies. However, semen cryopreservation negatively affects sperm quality, rendering a high proportion (over 50%) of dead and cryocapacitated spermatozoa with low fertilizing potential. To obtain a population of functional spermatozoa, a selection procedure must be applied. Our group recently reported in the Theriogenology journal (2012; 78:201-209) a comprehensive study that demonstrates the effectiveness of the glass wool filtration procedure to select functional spermatozoa from frowen-thawed semen samples in a fast, low-cost and simple fashion. High percentages of live spermatozoa (94±3%), with progressive motility (89±4%), mainly non- capacitated (80±10%), with intact acrosomes (98±1%), and capable to fertilize oocytes in vitro were recovered in the filtrate. The glass wool sperm filtration procedure rendered a yield of 67±19%, ~4 times higher than the Swim up. In conclusion, sperm filtration through glass wool columns is a valid alternative to be incorporated in the bull reproductive technologies, and may be suitable for other domestic and farm animals as well as to endangered species.
Responsabilidad civil de directores de instituciones financieras en el derecho societario en los Estados Unidos
Miguens, Héctor José
Estudio de la responsabilidad civil de directores de entidades financieras (entre ellas de bancos comerciales) en el derecho de los Estados Unidos de America conforme a las normas de la jurisprudencia y de ordenamientos estatutarios sobre la cuestión.; In this paper the author studies the cases treated by local and federal case law and statutes in the United States of America on the issue of liability of directors of financial institutions (mainly banks). The work studies the most important court cases and books and articles by authors specializing in the issue of liability of directors of companies, especially financial institutions in the United States of America. In the final part the author highlights the key findings of the investigation.
