¿Qué es la UNASUR?: Una descripción en base del análisis de política exterior de Brasil, Venezuela y Argentina

Este trabajo es un aporte al análisis de la relación entre tres Estados miembros de la UNASUR, Brasil, Venezuela y Argentina. El objetivo es analizar las políticas exteriores y las estrategias geopolíticas para detectar cuáles tienen implicancia para la UNASUR. Se registró que la UNASUR es una combinación de intereses y objetivos que forman un espacio de cooperación en donde convergen y se complementan las estrategias geopolíticas de los gobiernos

Polypropylene degrading actinobacteria

La acumulación de polímeros sintéticos es un gran problema de contaminación ambiental, ya que no existen métodos eficientes para su eliminación segura; sin embargo, hay evidencias sobre su degradación por actinobacterias. En este trabajo se evaluó la capacidad de degradación de actinobacterias aisladas de suelo del vertedero de Bariloche, sobre tres biopolímeros y un polímero sintético. Por un lado, se estudió la degradación de polímeros naturales (almidón, hemicelulosa, celulosa) en medio sólido, y por otro el otro se evaluó la degradación de láminas de polipropileno inoculadas con los aislamientos y cultivadas en medio líquido durante seis semanas a 37 ºC. Luego se midió la pérdida de peso en las láminas y se estudió la colonización de la superficie del polipropileno mediante microscopia óptica y electrónica. Los datos fueron analizados con un ANOVA de dos vías y la prueba de Tukey. De los 35 aislamientos totales, el 88 % correspondió al género Streptomyces y el 3 % a los demás géneros (Actinomadura, Pseudonocardia, Saccharomonospora y Thermoactinomyces). El 63 % de los aislamientos tuvo la capacidad de degradar almidón, el 86 % hemicelulosa, el 34 % celulosa microcristalina (exoglucanasas) y el 88 % carboximetilcelulosa (endoglucanasas). Se observó colonización de la superficie de polipropileno en todos los tratamientos. Dos de las cepas estudiadas (Streptomyces sp. MP32 y Actinomadura sp. MP5) redujeron el peso de las láminas de polipropileno (p ≤ 0.05). Estos resultados preliminares muestran la capacidad de las actinobacterias para colonizar la superficie del polipropileno, con potencial uso en suelos o ambientes contaminados por plásticos.The accumulation of synthetic polymers is a great environmental contamination issue, since there are no efficient methods to dispose them safely; however, there is evidence about the degradation of plastics by actinobacteria. In this work we tested the degradation capacity of tree biopolymers and a synthetic polymer by actinobacteria isolated from the soil of a landfill in Bariloche. On the one hand, we studied the degradation of natural polymers (starch, hemicellulose, cellulose) in a solid medium, and on the other hand, we studied the degradation of polypropylene sheets inoculated with the isolates and cultured in liquid medium for six weeks at 37 ºC. We then measured weight loss in the sheets and studied colonization of the polypropylene surface using light and electron microscopy. The data were analyzed with a two-way ANOVA and Tukey’s test. Of the 35 total isolates, 88 % corresponded to the Streptomyces genus and 3 % to the rest of genera (Actinomadura, Pseudonocardia, Saccharomonospora and Thermoactinomyces). Of the isolates, 63 % were able to degrade starch, 86 % hemicellulose, 34 % microcrystalline cellulose (exoglucanases), and 88% carboxymethyl cellulose (endoglucanases). Colonization of the polypropylene surface was observed in all treatments. Two of the strains studied, Streptomyces sp. MP32 and Actinomadura sp. MP5 reduced the weight of the polypropylene sheets (p ≤ 0.05). These preliminary results show the ability of actinobacteria to colonize the polypropylene surface, with potential use in soils or environments contaminated by synthetic polymers.Fil: Boenel, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; ArgentinaFil: Vobis, Gernot. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Solans, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Ácidos grasos como marcadores de las relaciones tróficas entre el sestón, el zooplancton crustáceo y el sifonóforo Nanomia cara en Georges Basin y el cañón Oceanographer (NO Atlántico)

[EN] Fatty acid concentrations expressed as percentages of total fatty acid pools in seston, stage V copepodites of Calanus finmarchicus, adults of the euphausiid Meganyctiphanes norvegica, and the physonect siphonophore Nanomia cara were used to elucidate trophic links in Georges Basin and Oceanographer Canyon in September 2003. Seston at both locations was refractory and comprised mainly of saturated fatty acids. Phytoplankton did not contribute significantly to the fatty acid composition of seston or higher trophic levels. Only four fatty acids, i.e. 14:0, 16:0, 16:1 (n–7) and 18:1 (n–7), were transferred from seston to C. finmarchicus or M. norvegica, which suggested weak trophic interactions. Fatty acids transferred from the two species of crustaceans to N. cara included the same four fatty acids, along with three polyunsaturated fatty acids found in relatively high concentrations in both crustaceans, i.e. 20:3 (n–6), 20:5 (n–3) and 22:6 (n–3). In addition, 18:1 (n–9), which occurred in relatively high concentrations only in M. norvegica, and 18:0 and 18:2 (n–6), which were found in low concentrations in both crustaceans, also appeared to be transferred to N. cara. Overall, fatty acid trophic markers proved useful for identifying trophic links to N. cara[ES] En este estudio se utilizaron las concentraciones de ácidos grasos (expresadas como porcentajes) para identificar posibles relaciones tróficas entre el seston, el estadio V (copepoditos) de Calanus finmarchicus, los adultos del eufáusido Meganyctiphanes norvegica, y el sifonóforo fisonecto Nanomia cara en Georges Basin y el cañón submarino Oceanographer durante Septiembre de 2003. En ambos lugares el seston era muy refractario y compuesto básicamente por ácidos grasos saturados. El fitoplancton no contribuyó de forma significativa a la composición de ácidos grasos del seston o de niveles tróficos superiores. Sólo cuatro ácidos grasos [14:0, 16:0, 16:1 (n–7) y 18:1 (n–7)] se transfirieron potencialmente del seston a C. finmarchicus o M. norvegica, lo que sugiere una débil conexión trófica entre estos eslabones de la cadena. Los ácidos grasos transferidos de las dos especies de zooplancton crustáceo a N. cara incluyen los mismos descritos más arriba y otros tres ácidos grasos poliinsaturados [20:3 (n–6), 20:5 (n–3) y 22:6 (n–3)] encontrados en concentraciones relativamente elevadas en ambos crustáceos. Además, tanto el 18:1 (n–9) (encontrado en elevadas concentraciones en M. norvegica) y los 18:0 y 18:2 (n–6) (encontrados en bajas concentraciones en ambas especies de crustáceos) se transfieren a N. cara. Los ácidos grasos demuestran ser una herramienta útil para identificar conexiones tróficas en N. caraA grant to MJY from the National Science Foundation (NSF-0002493), the European Project EUROGEL, and USDA CRIS Project FLA-FAS-03978 supported this workPeer reviewe

Discovery of long-distance gamete dispersal in a lichen-forming ascomycete

Accurate estimates of gamete and offspring dispersal range are required for the understanding and prediction of spatial population dynamics and species persistence. Little is known about gamete dispersal in fungi, especially in lichen-forming ascomycetes. Here, we estimate the dispersal functions of clonal propagules, gametes and ascospores of the epiphytic lichen Lobaria pulmonaria. We use hierarchical Bayesian parentage analysis, which integrates genetic and ecological information from multiannual colonization and dispersal source data collected in a large, oldgrowth forest landscape. The effective dispersal range of gametes is several hundred metres to kilometres from potential paternal individuals. By contrast, clonal propagules disperse only tens of metres, and ascospores disperse over several thousand metres. Our study reveals the dispersal distances of individual reproductive units; clonal propagules, gametes and ascospores, which is of great importance for a thorough understanding of the spatial dynamics of ascomycetes. Sexual reproduction occurs between distant individuals. However, whereas gametes and ascospores disperse over long distances, the overall rate of colonization of trees is low. Hence, establishment is the limiting factor for the colonization of new host trees by the lichen in old- growth landscapes.Peer reviewe

Fleas as parasites of the family Canidae

Historically, flea-borne diseases are among the most important medical diseases of humans. Plague and murine typhus are known for centuries while the last years brought some new flea-transmitted pathogens, like R. felis and Bartonella henselae. Dogs may play an essential or an accidental role in the natural transmission cycle of flea-borne pathogens. They support the growth of some of the pathogens or they serve as transport vehicles for infected fleas between their natural reservoirs and humans. More than 15 different flea species have been described in domestic dogs thus far. Several other species have been found to be associated with wild canids. Fleas found on dogs originate from rodents, birds, insectivores and from other Carnivora. Dogs therefore may serve as ideal bridging hosts for the introduction of flea-borne diseases from nature to home. In addition to their role as ectoparasites they cause nuisance for humans and animals and may be the cause for severe allergic reactions

Morphological Convergence in Forest Microfungi Provides a Proxy for Paleogene Forest Structure

Amber, fossilized plant resin from gymnosperms and angiosperms, is renowned for preserving a wide range of organisms in microscopic fidelity. These so-called amber inclusions comprise many groups of organisms, ranging from bacteria to arthropods and vertebrates. Calicioid lichens and fungi, which are from now on referred to as “calicioids,” constitute a diverse group of tiny ascomycetes with superficially similar, usually well-stalked ascomata and which often accumulate mature ascospores on top of the apothecial disk to form a true mazaedium. The aim of this study is to use all available information on the morphology and ecology of extant calicioids to reconstruct the substrate and habitat ecology of known fossil calicioids and then to use this information to open new insights into the stand structure and ecological conditions of European Paleogene amber forests. First, we introduce the morphology of extant calicioids and demonstrate that their structural features are intimately linked to habitat ecology and are instrumental for successful dispersal; we also explain the conspicuous morphological convergence between phylogenetically distant calicioid fungi. Then, we show that the adaptive traits of calicioids have not changed since at least the Eocene, and argue that their fundamental niches also have remained unchanged. Finally, we summarize what the diversity and relative abundance of fossil calicioids in amber tells us about the ecological conditions that once prevailed in European amber forests.Peer reviewe