The Effects of Intrahippocampal Estradiol Administration on Spatial Memory and Protein Expression in Rats Fed a High Fat Diet

Estradiol acts throughout the body; one key target that expresses large numbers of estradiol receptors is the brain, and specifically the hippocampus. Estradiol can exhibit neuroprotective effects in the brain. However, the set of pathways through which this occurs is not well understood. In vitro work has shown that administration of estradiol to hippocampal neurons inactivates caspase 3, a protease involved in apoptosis and the cleavage of tau. Cleavage of tau results in the formation of neurofibrillary tangles. Together with formation of amyloid-beta plaques, this is one of the hallmarks of Alzheimer’s disease. We tested the hypothesis that administration of estradiol to rats might attenuate the cognitive impairment caused by the ingestion of a high fat, diabetogenic diet whose long-term consumption causes insulin resistance and Alzheimer’s disease pathologies. Administration of estradiol unexpectedly did not ameliorate the impairment seen on a spatial working memory task or a novel object recognition task. In addition to behavioral measures, post-mortem analyses of hippocampal tissue measured molecular markers associated with estradiol signaling and memory formation. Ultimately, this study aims to elucidate mechanisms involved in a possible neuroprotective role for estradiol in individuals prone to cognitive dysfunction brought about by metabolic disease

Quantification of purine basis in their mixtures at femto-molar concentration levels using FT-SERS

Surface-enhanced Raman scattering spectroscopy represents one of the unique techniques for studying nanoscale objects, and its distinctive properties can be used in the process of further analysis. The careful evaluation of the particular influence of selected key-role experimental parameters (e.g. pH value of measured sample mixture, size and distribution of used nanoparticles) and the influence of reduction agent used in the process of formation of desired nanoparticle objects presents an important task in the further study of surface-enhanced Raman scattering effect. A broad study of these experimental parameters was performed in this paper. The main aim of the presented work was to a demonstrate an application potential of selected experimental conditions in the determination of three purine bases: adenine, xanthine, and hypoxanthine. The resulting limits of detection are at femtomolar concentration levels for all three studied compounds

Antecedents and consequences of satisfaction and guilt following ingroup aggression

Three studies investigated the role of intergroup satisfaction in intergroup confl ict. After reading about real acts of aggression committed by an ingroup, participants reported how those actions made them feel and how much they would support similar aggression in the future. In all three studies, experiencing intergroup satisfaction increased support for similar aggression, whereas experiencing intergroup guilt decreased support for similar aggression. Study 2 showed that ingroup identifi cation increased justifi cation appraisals, which increased satisfaction and decreased guilt, and thus increased support for future aggression. Study 3 provided an experimental test of the model: when justifi cation appraisals were manipulated, emotion and support for further aggression changed accordingly. These fi ndings demonstrate conditions under which intergroup satisfaction can facilitate and sustain intergroup confl ict

Late Quaternary climate legacies in contemporary plant functional composition

The functional composition of plant communities is commonly thought to be determined by contemporary climate. However, if rates of climate‐driven immigration and/or exclusion of species are slow, then contemporary functional composition may be explained by paleoclimate as well as by contemporary climate. We tested this idea by coupling contemporary maps of plant functional trait composition across North and South America to paleoclimate means and temporal variation in temperature and precipitation from the Last Interglacial (120 ka) to the present. Paleoclimate predictors strongly improved prediction of contemporary functional composition compared to contemporary climate predictors, with a stronger influence of temperature in North America (especially during periods of ice melting) and of precipitation in South America (across all times). Thus, climate from tens of thousands of years ago influences contemporary functional composition via slow assemblage dynamics

Leaf size of woody dicots predicts ecosystem primary productivity

A key challenge in ecology is to understand the relationships between organismal traits and ecosystem processes. Here, with a novel dataset of leaf length and width for 10 480 woody dicots in China and 2374 in North America, we show that the variation in community mean leaf size is highly correlated with the variation in climate and ecosystem primary productivity, independent of plant life form. These relationships likely reflect how natural selection modifies leaf size across varying climates in conjunction with how climate influences canopy total leaf area. We find that the leaf size–primary productivity functions based on the Chinese dataset can predict productivity in North America and vice-versa. In addition to advancing understanding of the relationship between a climate-driven trait and ecosystem functioning, our findings suggest that leaf size can also be a promising tool in palaeoecology for scaling from fossil leaves to palaeo-primary productivity of woody ecosystems

Informing trait-based ecology by assessing remotely sensed functional diversity across a broad tropical temperature gradient

Spatially continuous data on functional diversity will improve our ability to predict global change impacts on ecosystem properties. We applied methods that combine imaging spectroscopy and foliar traits to estimate remotelysensed functional diversity in tropical forests across an Amazon-to-Andes elevation gradient (215 to 3537 m). We evaluated the scale dependency of community assembly processes and examined whether tropical forest productivitycould be predicted by remotely sensed functional diversity. Functional richness of the community decreased withincreasing elevation. Scale-dependent signals of trait convergence, consistent with environmental filtering, play animportant role in explaining the range of trait variation within each site and along elevation. Single- and multitraitremotely sensed measures of functional diversity were important predictors of variation in rates of net and grossprimary productivity. Our findings highlight the potential of remotely sensed functional diversity to inform trait-based ecology and trait diversity-ecosystem function linkages in hyperdiverse tropical forests.Fil: Durán, Sandra M.. University of Arizona; Estados UnidosFil: Martin, Roberta E.. Arizona State University; Estados UnidosFil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Maitner, Brian S.. Arizona State University; Estados UnidosFil: Malhi, Yadvinder. University of Oxford; Reino UnidoFil: Salinas, Norma. University of Oxford; Reino Unido. Pontificia Universidad Católica de Perú; PerúFil: Shenkin, Alexander. University of Oxford; Reino UnidoFil: Silman, Miles R.. Wake Forest University; Estados UnidosFil: Wieczynski, Daniel J.. University of Oxford; Reino UnidoFil: Asner, Gregory P.. Arizona State University; Estados UnidosFil: Bentley, Lisa Patrick. Sonoma State University; Estados UnidosFil: Savage, Van M.. University of California; Estados UnidosFil: Enquist, Brian J.. Arizona State University; Estados Unido

occCite: Tools for querying and managing large biodiversity occurrence datasets

The amount of observational and specimen-based biodiversity data available to researchers is increasing exponentially, yet the ability to manage and cite large, complex biodiversity datasets lags behind. This management and citation gap impedes reproducibility for data users and the ability for data publishers to track use and accumulate use citations, ultimately harming the longer-term sustainability of the still-emerging enterprise of research data-sharing. Here we present an R package, occCite (v. 0.4.7), to aid researchers in querying large species occurrence data aggregators (specifically, the Global Biodiversity Information Facility, GBIF, and the Botanical Information and Ecology Network, BIEN), and store metadata such as primary data providers, database accession dates, DOIs, and the taxonomic source used for search terms. occCite also includes tools to summarize and visualize query results and generate citation lists of all data providers and software packages used during the query process. We provide examples of a basic occurrence search and citation workflow as well as an advanced workflow using features for custom optimized searches, visualization, and summary procedures. occCite improves upon existing R packages by uniting data from powerful API-based query packages (rgbif and BIEN) into a unified object-based framework, while maintaining metadata vital to best-practice recommendations for documenting biodiversity analysis workflows. occCite aims to efficiently close the gap in the citation cycle between primary data providers and final research products, allowing researchers to meet dataset documentation standards without sacrificing time and resources to the demands of providing increasing levels of detail on their datasets

Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming

In the high Arctic, plant community species composition generally responds slowly to climate warming, whereas less is known about the community functional trait responses and consequences for ecosystem functioning. The slow species turnover and large distribution ranges of many Arctic plant species suggest a significant role of intraspecific trait variability in functional responses to climate change. Here we compare taxonomic and functional community compositional responses to a long-term (17-year) warming experiment in Svalbard, Norway, replicated across three major high Arctic habitats shaped by topography and contrasting snow regimes. We observed taxonomic compositional changes in all plant communities over time. Still, responses to experimental warming were minor and most pronounced in the drier habitats with relatively early snowmelt timing and long growing seasons (Cassiope and Dryas heaths). The habitats were clearly separated in functional trait space, defined by 12 size- and leaf economics-related traits, primarily due to interspecific trait variation. Functional traits also responded to experimental warming, most prominently in the Dryas heath and mostly due to intraspecific trait variation. Leaf area and mass increased and leaf δ15N decreased in response to the warming treatment. Intraspecific trait variability ranged between 30% and 71% of the total trait variation, reflecting the functional resilience of those communities, dominated by long-lived plants, due to either phenotypic plasticity or genotypic variation, which most likely underlies the observed resistance of high Arctic vegetation to climate warming. We further explored the consequences of trait variability for ecosystem functioning by measuring peak season CO2 fluxes. Together, environmental, taxonomic, and functional trait variables explained a large proportion of the variation in net ecosystem exchange (NEE), which increased when intraspecific trait variation was accounted for. In contrast, even though ecosystem respiration and gross ecosystem production both increased in response to warming across habitats, they were mainly driven by the direct kinetic impacts of temperature on plant physiology and biochemical processes. Our study shows that long-term experimental warming has a modest but significant effect on plant community functional trait composition and suggests that intraspecific trait variability is a key feature underlying high Arctic ecosystem resistance to climate warming.publishedVersio