Environmental Determinants of the Distribution and Abundance of the Ants, Lasiophanes picinus and L. valdiviensis, in Argentina

The distribution and abundance variation of the terrestrial ants, Lasiophanes picinus and Lasiophanes valdiviensis Emery (Formicinae: Lasiini), which are endemic in Patagonia (Argentina and Chile), are described and a set of environmental factors are examined to explain the observed patterns. Ants were collected using 450 pitfall traps arranged in 50, 100 m2 grid plots each with nine traps within a roughly 150 × 150 km area representative of the subantartic-patagonian transition of Argentina. Five sampling periods each 8-days long were carried out between November 2004 and March 2006. To understand the distributional patterns and their link to environmental variables discriminant analysis was used. Path analysis was performed to test for direct and indirect effects of a set of environmental variables on species abundance variation. L. picinus was more frequently captured and attained higher abundance in the forests, while L. valdiviensis was more frequently captured and more abundant in the scrubs. The maximum daily temperature and mean annual precipitation explained L. picinus distribution (i.e. presence or absence) with an accuracy of 90%. L. valdiviensis distribution was predicted with almost 70% accuracy, taking into account herbal richness. The maximum daily temperature was the only climatic variable that affected ant abundance directly; an increase in temperature led to an increase of L. picinus abundance and a decrease of L. valdiviensis abundance. The amount of resources, as indicated by the percent plant cover, explained the variation of the abundance of both species better than the variety of resources as indicated by plant richness (i.e. models including plant richness had low fit or no fit at all). A direct effect of habitat use by cattle was found, as indicated by the amount of feces in the plots, only when variables related to the amount of resources were replaced by variables with less explanatory power related to the variety of resources. This study provides new data on the ecology of Lasiophanes species in relation to existing hypotheses proposed to explain patterns of abundance variation. Evidence is provided that changes in temperature (i.e. global climate change) may have important consequences on populations of these species

High cell-free DNA is associated with disease progression, inflammasome activation and elevated levels of inflammasome-related cytokine IL-18 in patients with myelofibrosis

Myelofibrosis (MF) is a clonal hematopoietic stem cell disorder classified among chronic myeloproliferative neoplasms, characterized by exacerbated myeloid and megakaryocytic proliferation and bone marrow fibrosis. It is induced by driver (JAK2/CALR/MPL) and high molecular risk mutations coupled to a sustained inflammatory state that contributes to disease pathogenesis. Patient outcome is determined by stratification into risk groups and refinement of current prognostic systems may help individualize treatment decisions. Circulating cell-free (cf)DNA comprises short fragments of double-stranded DNA, which promotes inflammation by stimulating several pathways, including inflammasome activation, which is responsible for IL-1β and IL-18 maturation and release. In this work, we assessed the contribution of cfDNA as a marker of disease progression and mediator of inflammation in MF. cfDNA was increased in MF patients and higher levels were associated with adverse clinical outcome, a high-risk molecular profile, advanced disease stages and inferior overall survival, indicating its potential value as a prognostic marker. Cell-free DNA levels correlated with tumor burden parameters and markers of systemic inflammation. To mimic the effects of cfDNA, monocytes were stimulated with poly(dA:dT), a synthetic double-stranded DNA. Following stimulation, patient monocytes released higher amounts of inflammasome-processed cytokine, IL-18 to the culture supernatant, reflecting enhanced inflammasome function. Despite overexpression of cytosolic DNA inflammasome sensor AIM2, IL-18 release from MF monocytes was shown to rely mainly on the NLRP3 inflammasome, as it was prevented by NLRP3-specific inhibitor MCC950. Circulating IL-18 levels were increased in MF plasma, reflecting in vivo inflammasome activation, and highlighting the previously unrecognized involvement of this cytokine in MF cytokine network. Monocyte counts were higher in patients and showed a trend towards correlation with IL-18 levels, suggesting monocytes represent a source of circulating IL-18. The close correlation shown between IL-18 and cfDNA levels, together with the finding of enhanced DNA-triggered IL-18 release from monocytes, suggest that cfDNA promotes inflammation, at least in part, through inflammasome activation. This work highlights cfDNA, the inflammasome and IL-18 as additional players in the complex inflammatory circuit that fosters MF progression, potentially providing new therapeutic targets.Fil: de Luca, Geraldine. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Lev, Paola Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Camacho, Maria F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Goette, Nora Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Sackmann, Federico. Fundación Para Combatir la Leucemia; ArgentinaFil: Castro Ríos, Miguel A.. No especifíca;Fil: Moiraghi, Beatriz. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Cortes Guerrieri, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Bendek, Georgina. Hospital Italiano; ArgentinaFil: Carricondo, Emiliano. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Enrico, Alicia. Hospital Italiano; ArgentinaFil: Vallejo, Veronica. Instituto Cardiovascular de Buenos Aires; ArgentinaFil: Varela, Ana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Khoury, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Gutierrez, Marina. Laboratorio Stamboulian; ArgentinaFil: Larripa, Irene Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Marta, Rosana Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Glembotsky, Ana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Heller, Paula Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentin

High cell-free DNA is associated with disease progression, inflammasome activation and elevated levels of inflammasome-related cytokine IL-18 in patients with myelofibrosis

Myelofibrosis (MF) is a clonal hematopoietic stem cell disorder classified among chronic myeloproliferative neoplasms, characterized by exacerbated myeloid and megakaryocytic proliferation and bone marrow fibrosis. It is induced by driver (JAK2/CALR/MPL) and high molecular risk mutations coupled to a sustained inflammatory state that contributes to disease pathogenesis. Patient outcome is determined by stratification into risk groups and refinement of current prognostic systems may help individualize treatment decisions. Circulating cell-free (cf)DNA comprises short fragments of double-stranded DNA, which promotes inflammation by stimulating several pathways, including inflammasome activation, which is responsible for IL-1β and IL-18 maturation and release. In this work, we assessed the contribution of cfDNA as a marker of disease progression and mediator of inflammation in MF. cfDNA was increased in MF patients and higher levels were associated with adverse clinical outcome, a high-risk molecular profile, advanced disease stages and inferior overall survival, indicating its potential value as a prognostic marker. Cell-free DNA levels correlated with tumor burden parameters and markers of systemic inflammation. To mimic the effects of cfDNA, monocytes were stimulated with poly(dA:dT), a synthetic double-stranded DNA. Following stimulation, patient monocytes released higher amounts of inflammasome-processed cytokine, IL-18 to the culture supernatant, reflecting enhanced inflammasome function. Despite overexpression of cytosolic DNA inflammasome sensor AIM2, IL-18 release from MF monocytes was shown to rely mainly on the NLRP3 inflammasome, as it was prevented by NLRP3-specific inhibitor MCC950. Circulating IL-18 levels were increased in MF plasma, reflecting in vivo inflammasome activation, and highlighting the previously unrecognized involvement of this cytokine in MF cytokine network. Monocyte counts were higher in patients and showed a trend towards correlation with IL-18 levels, suggesting monocytes represent a source of circulating IL-18. The close correlation shown between IL-18 and cfDNA levels, together with the finding of enhanced DNA-triggered IL-18 release from monocytes, suggest that cfDNA promotes inflammation, at least in part, through inflammasome activation. This work highlights cfDNA, the inflammasome and IL-18 as additional players in the complex inflammatory circuit that fosters MF progression, potentially providing new therapeutic targets

Coefficient shifts in geographical ecology: an empirical evaluation of spatial and non-spatial regression

Copyright © 2009 The Authors. Copyright © ECOGRAPHY 2009.A major focus of geographical ecology and macro ecology is to understand the causes of spatially structured ecological patterns. However, achieving this understanding can be complicated when using multiple regressions, because the relative importance of explanatory variables, as measured by regression coefficients, can shift depending on whether spatially explicit or non-spatial modelling is used. However, the extent to which coefficients may shift and why shifts occur are unclear. Here, we analyze the relationship between environmental predictors and the geographical distribution of species richness, body size, range size and abundance in 97 multi-factorial data sets. Our goal was to compare standardized partial regression coefficients of non-spatial ordinary least squares regressions (i.e. models fitted using ordinary least squares without taking autocorrelation into account; “OLS models” hereafter) and eight spatial methods to evaluate the frequency of coefficient shifts and identify characteristics of data that might predict when shifts are likely. We generated three metrics of coefficient shifts and eight characteristics of the data sets as predictors of shifts. Typical of ecological data, spatial autocorrelation in the residuals of OLS models was found in most data sets. The spatial models varied in the extent to which they minimized residual spatial autocorrelation. Patterns of coefficient shifts also varied among methods and datasets, although the magnitudes of shifts tended to be small in all cases. We were unable to identify strong predictors of shifts, including the levels of autocorrelation in either explanatory variables or model residuals. Thus, changes in coefficients between spatial and non-spatial methods depend on the method used and are largely idiosyncratic, making it difficult to predict when or why shifts occur. We conclude that the ecological importance of regression coefficients cannot be evaluated with confidence irrespective of whether spatially explicit modelling is used or not. Researchers may have little choice but to be more explicit about the uncertainty of models and more cautious in their interpretation

Efectos de la variación temporal y los métodos de captura en la eficiencia de un muestreo de coleópteros en la Reserva Natural Loma del Medio, El Bolsón, Río Negro Effects of temporal variation and trapping methods on the efficiency of Coleoptera sampling in Loma del Medio Nature Reserve, El Bolsón, Río Negro

En este trabajo se analiza la eficiencia de un muestreo sistemático para una comunidad de coleópteros de bosque subantártico. En particular se evalúa: 1- la conveniencia de repartir el esfuerzo de muestreo a lo largo del tiempo (dentro de una misma temporada de actividad de insectos y entre años), y 2- la eficiencia del uso de dos tipos de trampas diferentes. Se seleccionaron 10 sitios en un bosque de Austrocedrus chilensis (Cupresaceae) y Nothofagus dombeyii (Fagaceae) en la Reserva Forestal Loma del Medio, El Bolsón, Río Negro. En cada sitio se colocaron nueve trampas de caída que abarcaban una superficie de 100 m² y una trampa Malaise. Se realizaron cuatro muestreos anuales (enero, febrero, marzo y abril) durante tres años (2002-2004), y de una semana de duración cada uno. La abundancia de especies fue mayor en enero-febrero que en marzo-abril, la riqueza fue similar y la composición de la comunidad fue marcadamente distinta entre dichos períodos para los tres años. Por otro lado, la riqueza de especies fue similar al considerar uno, dos o tres años de muestreo, y en general la composición de la comunidad no varió entre años para períodos comparables. Sin embargo, la acumulación de especies raras sólo se estabilizó luego de tres años de muestreo. Aunque las trampas Malaise fueron más eficientes (número de especies observadas / individuos capturados) que las trampas de caída, los métodos de captura fueron altamente complementarios (25% de especies en común). Para caracterizar esta comunidad en particular, se recomienda distribuir el esfuerzo de muestreo a lo largo de una misma temporada de actividad y aplicar diferentes métodos de muestreos. Con un año de muestreo, bajo las condiciones propuestas anteriormente, se podrá caracterizar la comunidad de forma general, pero hacen falta al menos tres años de muestreo para alcanzar un alto grado de integridad. Se incluye un apéndice con la lista de especies capturadas (N = 175), de las cuales 14 son nuevos registros para Argentina.<br>The present study evaluates for a community of Coleoptera of sub-antartic forest the efficiency of a systematic sampling. In particular, the convenience of distributing sampling effort in time (at different moments within a season and between years) and the use of two different kinds of traps are evaluated. Ten sampling sites were selected in an Austrocedrus chilensis (Cupresaceae) and Nothofagus dombeyii (Fagaceae) forest within the Reserva Forestal Loma del Medio, El Bolsón, Río Negro. At each site, nine pitfall traps were placed covering a 100 m² surface, along with one Malaise trap. Four annual samplings (January, February, March and April) were carried out during three years (2002-2004). The abundance of species was higher in January-February than in March-April, while richness was similar and community composition differed markedly between periods for the three years. On the other hand, richness was similar when one, two or three years of sampling were considered and in general species composition was similar in different years for comparable periods. However, the accumulation of rare species became stable only after three years of sampling. Malaise traps were more efficient (number of species/individuals captured) than pitfall traps, but the sampling methods were highly complementary, capturing only 25% of species in common. In order to characterize the studied community it is recommended to that sampling efforts are distributed through a sampling season and that different trapping methods are used. Even though one year of sampling under the aforementioned conditions will be enough to have a general description of the Coleoptera community, at least three years will be necessary to reach a high level of sampling integrity. A list of species captured (N = 175), of which 14 are new records for Argentina, is included as an appendix

The spatial variation in ant species composition and functional groups across the Subantarctic-Patagonian transition zone

The role of ecotones in the maintenance of species diversity is rather controversial; they may represent either biodiversity hotspots with unique and rare forms, or be transitional areas that hold marginal populations of species. We analyse the taxonomic and functional composition of ant species assemblages across the Subantarctic-Patagonian transition to evaluate the role that transitional shrublands may play in the maintenance of the taxonomic and functional differentiation. We collected ants using 450 pitfall traps within a ~150 × 150 km area. Species were classified into functional groups in relation to stress and disturbance, and in foraging groups according to their foraging behavior. An indicator value for each species in each habitat was calculated. The steppes and the forests strongly differed in ant species and functional composition. Climatic effects combined with structural components of plant environment explained about 23–27 % of the variation in ant composition. The shrublands did not show a distinctive fauna, and show greater similarity in ant species composition and in the proportional occupancy of functional groups to the steppes than to the forests. They harbor neither rare nor indicator species, except for Lasiophanes valdiviensis, and thus this reinforces the idea that they are not a habitat source of species, but an area of encounter between two distinct forest- and steppe- ant faunas, where a high number of local distributional limits of ant species overlap.Fil: Fergnani, Paula Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; ArgentinaFil: Sackmann Braceras, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; ArgentinaFil: Ruggiero, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; Argentin

Temporal and spatial patterns of tenebrionid beetle diversity in NW Patagonia, Argentina

Spatial and temporal variation in abundance, richness and composition of Tenebrionidae beetle assemblages were described for north-western Patagonia. Beetles were collected using 450 pitfall traps arranged in 50 plots across an area of about 22,500 km2 representative of the Subantarctic-Patagonian transition of Argentina. The study area included three different habitats: forest, scrub, and steppe. Beetles were trapped at five, eight day sampling periods in spring-summer between November 2004 and March 2006. A total of 30 species and 938 individuals were collected. Total abundance was higher in November and January than in March, and species richness did not change among samplings. Species richness was greater in the steppe than scrub. Assemblages differed between the northern and southern transects. There was little correlation between the measured environmental variables and species composition. Historical factors might explain the observed patterns, but other environmental variables such as soil characteristics may be more informative in explaining the present distribution of tenebrionid species.Fil: Sackmann Braceras, Paula. 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: Flores, Gustavo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin