In Vitro and In Situ Characterization of Fish Thymic Nurse Cells

We present an enzyme- and immuno-cytochemical, and ultrastructural characterization of trout thymic nurse cells (TNCs). Our data suggest that isolated trout thymic multicellular complexes are epithelial cells with acidic compartments that may be involved in the processing of antigens and in the generation of the MHC-II proteins that these cell express, and also that isolated TNCs are the In Vitro equivalent of the pale and intermediate electronlucent epithelial cells located in the inner zone of the trout thymus, constituting indirect evidence of the phylogenetical relationships of the inner zone of the teleost thymus with the thymic cortex of higher vertebrates

Murid Herpesvirus-4 Exploits Dendritic Cells to Infect B Cells

Dendritic cells (DCs) play a central role in initiating immune responses. Some persistent viruses infect DCs and can disrupt their functions in vitro. However, these viruses remain strongly immunogenic in vivo. Thus what role DC infection plays in the pathogenesis of persistent infections is unclear. Here we show that a persistent, B cell-tropic gamma-herpesvirus, Murid Herpesvirus-4 (MuHV-4), infects DCs early after host entry, before it establishes a substantial infection of B cells. DC-specific virus marking by cre-lox recombination revealed that a significant fraction of the virus latent in B cells had passed through a DC, and a virus attenuated for replication in DCs was impaired in B cell colonization. In vitro MuHV-4 dramatically altered the DC cytoskeleton, suggesting that it manipulates DC migration and shape in order to spread. MuHV-4 therefore uses DCs to colonize B cells

Geodiversity : a theoretical and applied concept

The concept of geodiversity appears to have grown out of the discussions around biodiversity, and has evolved over time to become both a tool and a theoretical concept. The paper presents an overview of this conceptual evolution, leading to formulation of the argument that geodiversity is a broader term than geological diversity. Consequently, it is proposed that the concept should take into account all abiotic elements, processes and relations to the natural system and human activity The overview serves as a basis for focussing on the constituent elements of geodiversity that lead to the richness of variety in biotopes, ecosystems or landscapes and that infiuence its use in theoretical, educative and geoconservation terms. The suggestion is made to include four levels in a hierarchy of abiotic diversity (particles, elements, places and landscapes). several approaches to measuring and quantifying geodiversity are discussed, pointing to a need for a geodiversity index which links the different physical elements with processes in the soil, hydrology and geomorphology, as well as with topographical factors (orientation, slope and radiation)

Diagnóstico de calidad para la conservación en espacios agrícolas en terrazas. Propuesta metodológica para la cuenca del Guiniguada (Gran Canaria, Islas Canarias)

In the present text it's exposed the designed method to set up the ranges of quality for the conservation of a hundred of unit of landscape where the presence of terraces is dominant. This rnethod value the characteristics of those unit relative of it's worth in productivity, ecology and scenery. The obtained results show that in the half and low areas of the Guiniguada valley, the spaces occupied by terraces present between a medium and high levels of quality for the conservation. 71% of the units are qualified by some one of these two categories, a high number bearing in mind that 60% of them are abandoned.En este trabajo se expone el método diseñado para el establecimiento de escalas de calidad para la conservación de un centenar de unidades de paisaje en las que domina la presencia de bancales. Dicho método tiene en cuenta las características productivas, ecológicas y paisajísticas de las áreas abancaladas. Los resultados obtenidos muestran que en la cuenca media y baja del Guiniguada (Gran Canaria), el espacio de bancales presenta una calidad para la conservación situada en niveles medios y altos. El 71% de las unidades se sitúan en alguna de estas dos categorías, cifra elevada teniendo en cuenta que el 60% de las mismas está abandonada

Type I Interferon Inhibition and Dendritic Cell Activation during Gammaherpesvirus Respiratory Infection▿

The respiratory tract is a major mucosal site for microorganism entry into the body, and type I interferon (IFN) and dendritic cells constitute a first line of defense against viral infections. We have analyzed the interaction between a model DNA virus, plasmacytoid dendritic cells, and type I IFN during lung infection of mice. Our data show that murine gammaherpesvirus 68 (γHV68) inhibits type I IFN secretion by dendritic cells and that plasmacytoid dendritic cells are necessary for conventional dendritic cell maturation in response to γHV68. Following γHV68 intranasal inoculation, the local and systemic IFN-α/β response is below detectable levels, and plasmacytoid dendritic cells are activated and recruited into the lung with a tissue distribution that differs from that of conventional dendritic cells. Our results suggest that plasmacytoid dendritic cells and type I IFN have important but independent roles during the early response to a respiratory γHV68 infection. γHV68 infection inhibits type I IFN production by dendritic cells and is a poor inducer of IFN-α/β in vivo, which may serve as an immune evasion strategy

Differences in streamflow after farmland abandonment –a comparative study in four small mountain catchments

Farmland abandonment usually leads to vegetation expansion with important environmentalconsequences. In this study, we assess the streamflow response at the flood event scale infive long-term monitored small headwater catchments in northern Spain. Three of them arerepresentative of different post farmland abandonment scenarios: natural revegetationdominated by shrubs (Arnás), afforestation (Araguás_afforestation) and abandoned terracedfields (Munilla). Two more cathments, covered by dense natural forest (San Salvador) andbadlands (Araguás), were used as reference for undisturbed and degraded environments,respectively.The five catchments registered a larger number of flood events in late autumn and spring,showing the influence of the Mediterranean climate. While the badlands, shrubs andafforested catchments generated events over the entire year, the terraced and forestedcatchments showed very limited response during the summer. Furthermore, the badlands,shrubs and afforested catchments recorded more than twice floods per year than the othertwo catchments. At the flood event, the mean runoff coefficient was higher in the badlandsand shrubs catchments. However, under wet conditions, both the forested and afforestedcatchments could registered high hydrological reponses, with similar runoff coefficients thanthose recorded in the badlands and shrubs. The terraced cathment showed the lowest runoffcoefficients. The highest peakflows were observed in the badlands catchment, charcaterizedby sharp flood hydrographs, suggesting the dominance of overland flow processes. The floodhydrographs of the abandoned catchments differed significantly, suggesting the influence ofboth vegetation cover and soil properties inherited from past agricultural activities. In theshrub catchment, peakflows were always greater; however, under very wet conditions and/orintense rainfalls, the afforested catchment recorded high peaks, comparable to that of theshrub catchment. The response time in both catchments were fast and recession limbs wereshort, suggesting the occurrence of ovelrand flow processes, probably over localized degradedareas. This greatly differed from the hydrographs of the terraced and forested catchments,characterized by gentler hydrographs, with long response times and recessions, indicatingsubsurface flow processes associated with thick and well developed soils. Differences in theland use legacy, which affects vegetation cover but also soil properties, may explain thedifferences in the hydrographs characteristics, suggesting contrasting dominant runoffgeneration processes in each catchment. These results highlight the need to consider thesedifferences to reduce future uncertainties in forecasting water resources and soil conservationin areas affected by farmland abandonmen

Differences in streamflow after farmland abandonment –a comparative study in four small mountain catchments

Farmland abandonment usually leads to vegetation expansion with important environmental consequences. In this study, we assess the streamflow response at the flood event scale in five long-term monitored small headwater catchments in northern Spain. Three of them are representative of different post farmland abandonment scenarios: natural revegetation dominated by shrubs (Arnás), afforestation (Araguás_afforestation) and abandoned terraced fields (Munilla). Two more cathments, covered by dense natural forest (San Salvador) and badlands (Araguás), were used as reference for undisturbed and degraded environments, respectively.The five catchments registered a larger number of flood events in late autumn and spring, showing the influence of the Mediterranean climate. While the badlands, shrubs and afforested catchments generated events over the entire year, the terraced and forested catchments showed very limited response during the summer. Furthermore, the badlands, shrubs and afforested catchments recorded more than twice floods per year than the other two catchments. At the flood event, the mean runoff coefficient was higher in the badlands and shrubs catchments. However, under wet conditions, both the forested and afforested catchments could registered high hydrological reponses, with similar runoff coefficients than those recorded in the badlands and shrubs. The terraced cathment showed the lowest runoff coefficients. The highest peakflows were observed in the badlands catchment, charcaterized by sharp flood hydrographs, suggesting the dominance of overland flow processes. The flood hydrographs of the abandoned catchments differed significantly, suggesting the influence of both vegetation cover and soil properties inherited from past agricultural activities. In the shrub catchment, peakflows were always greater; however, under very wet conditions and/or intense rainfalls, the afforested catchment recorded high peaks, comparable to that of the shrub catchment. The response time in both catchments were fast and recession limbs were short, suggesting the occurrence of ovelrand flow processes, probably over localized degraded areas. This greatly differed from the hydrographs of the terraced and forested catchments, characterized by gentler hydrographs, with long response times and recessions, indicating subsurface flow processes associated with thick and well developed soils. Differences in the land use legacy, which affects vegetation cover but also soil properties, may explain the differences in the hydrographs characteristics, suggesting contrasting dominant runoff generation processes in each catchment. These results highlight the need to consider these differences to reduce future uncertainties in forecasting water resources and soil conservation in areas affected by farmland abandonment