Microbiota and Microsatellite genotypes of Pacific oysters stemming from three oyster bed in the Northern Wadden Sea

Background: Studies of oyster microbiomes have revealed that a limited number of microbes, including pathogens, can dominate microbial communities in host tissues such as gills and gut. Much of the bacterial diversity however remains underexplored and unexplained, although environmental conditions and host genetics have been implicated. We used 454 next generation 16S rRNA amplicon sequencing of individually tagged PCR reactions to explore the diversity of bacterial communities in gill tissue of the invasive Pacific oyster Crassostrea gigas stemming from genetically differentiated beds under ambient outdoor conditions and after a multifaceted disturbance treatment imposing stress on the host. Results: While the gill associated microbial communities in oysters were dominated by few abundant taxa (i.e. Sphingomonas, Mycoplasma) the distribution of rare bacterial groups correlated to relatedness between the hosts under ambient conditions. Exposing the host to disturbance broke apart this relationship by removing rare phylotypes thereby reducing overall microbial diversity. Shifts in the microbiome composition in response to stress did not result in a net increase in genera known to contain potentially pathogenic strains. Conclusion: The decrease in microbial diversity and the disassociation between population genetic structure of the hosts and their associated microbiome suggest that disturbance (i.e. stress) may play a significant role for the assembly of the natural microbiome. Such community shifts may in turn also feed back on the course of disease and the occurrence of mass mortality events in oyster populations.

La cultura y las correlaciones metafísicas

Fil: Pró, Diego F.. Universidad Nacional de Cuyo. Facultad de Filosofía y Letras

Carbonate record of ODP Leg 167 sites

One of the expected scientific results of Ocean Drilling Program Leg 167 was to reconstruct the Neogene history of biogenic calcium carbonate accumulation in the northeastern Pacific along the California margin (Lyle, Koizumi, Richter, et al., 1997). This aims to constrain inorganic carbon burial rates, deep-water hydrography in the North Pacific, and linkages between deep Atlantic and Pacific circulation and carbonate accumulation or dissolution patterns. Data are presented for four sites. Two of them are located in the California bight-East Cortez Basin (Site 1012: 32°16.970?N 118°23.024?W, 1773 m) and San Nicholas Basin (Site 1013: 32°48.040??, 118°53.992?W, 1564 m). The others are the dedicated Hole 1017E at Site 1017 (34°32.099?N, 121°6.430?W, 955 m) and Site 1019 in the Eel River Basin (41¢X40.972?N, 124°55.975?W, 977 m). Reconstruction of paleo-sea-surface temperatures (SST) by determining the alkenone unsaturation index of the extractable organic matter is an independent technique and helps to verify oxygen-isotope-based estimates. Results from the uppermost 600 cm of the dedicated Hole 1017E are expected to reveal the local temperature history of the last 30 k.y.

Coleccionar y comprender : Voces populares en la biblioteca modernista

El coleccionismo, como lógica privada para incorporar los objetos del mundo exterior, es una de las actividades asociadas a la estructura de sentimiento modernista que, en una fase más avanzada, reorienta sus intereses artísticos hacia la conquista de lo prosaico, y comienza a revisar los estereotipos culturales de lo nativo. Entre estos estereotipos se distingue el interés por el diálogo popular, que es percibido como objet trouvé e integrado en "El gran descubrimiento: los poderes secretos del lenguaje coloquial" (Octavio Paz). El presente trabajo pretende indagar los alcances de estas actitudes que conjugan lo privado (el coleccionismo) con la aproximación al panorama de los nuevos actores sociales, el registro de sus voces, en el caso de escritores que adscriben más o menos explícitamente a las propuestas modernistas (Emilio Becher, Emilio Ortiz Grognet, Charles de Soussens, Juan José de Soiza Reilly) en algunos casos, a su vez, inmersos en los medios de prensa, el foro en el que todas las voces se reúnen y se interpelan

La leyenda de la llorona en La guerra gaucha de Leopoldo Lugones

Dentro del contexto de unión e identidad latinoamericanas, se hace indispensable revisar los textos literarios del pasado en donde se intentaron dar muestras de las prácticas culturales y religiosas previas a los procesos de conquista e independencia. Es así como la figura de la llorona aparece, en este cuento de Lugones, en la época de las "guerras gauchas", aunando elementos tanto criollos como indígenas, transformándose en un ícono nacional. Hay, entonces, un proceso de apropiación de lo autóctono que remite a la patria grande, pero también una singularización que remite a un movimiento nacionalista.