The Role of Disease and Ectoparasites in the Ecology of Nestling Golden Eagles

Climate and anthropogenic land use changes can alter biological communities and affect disease infection rates and parasite species distribution and abundance. Management to mitigate the threats of emerging infectious diseases and parasite species requires identifying and understanding factors that influence individual susceptibility within populations. Golden eagles (Aquila chrysaetos) in southwestern Idaho face several current and emerging threats, including a landscape-mediated diet shift that has increased the potential for disease infection, and warming temperatures that may increase the distribution and abundance of hematophagous ectoparasites. We examined prevalence of Trichomonas gallinae infection in golden eagle nestlings across western North America in 2015 and conducted a detailed study of the risk factors associated with T. gallinae infection in southwestern Idaho. We also quantified the abundance of Mexican chicken bug (Haematosiphon inodorus; Hemiptera: Cimicidae) in golden eagle nests in southwestern Idaho in 2015 and 2016. We developed a pit fall trap method to measure H. inodorus abundance, investigated factors that might affect abundance in nests, tested the ‘nest protection’ hypothesis that eagles modify nest sites to reduce the effects of ectoparasitism, and measured the physiological effects of ectoparasitism on nestlings. In our study of T. gallinae, we found a 6% infection rate distributed broadly across our western North America study area, with a relatively high T. gallinae infection rate, 41%, in Idaho. The probability of T. gallinae infection increased as the proportion of rock pigeons in nestling diet increased. Landscape-level change in southwestern Idaho is related to an increase in eagle diet diversity, and an increase in rock pigeons in nestling diet increased the probability of T. gallinae infection. In our study of H. inodorus, we found that eagles reuse less parasitized nests in successive years, and that south-facing nests and nests with later phenology had higher H. inodorus abundance. We found support for the ‘nest protection’ hypothesis. Golden eagles selected gray rabbitbrush as nest material, a plant that has high phenolic concentrations relative to others available on the landscape, and aromatic nest material had a positive effect on nestling hematocrit, suggesting these nest additions reduced the effects of ectoparasitism on nestlings. We found that increased ectoparasitism reduced nestling mass and hematocrit, and increased the probability that nestlings either fledged early or died in the nest. Nestling circulating corticosterone, which may act as a mechanism in the timing of fledging behavior, increased relative to ectoparasite infestation levels. Our results suggest that the current and emerging threats of disease and ectoparasites have the potential to negatively affect golden eagle productivity in southwestern Idaho. Although our data suggest there is a low incidence of T. gallinae infection in golden eagle populations across western North America, shifts in eagle diet, that result from habitat degradation and loss of historical prey resources, have the potential to affect golden eagle nestling survival. In addition, the presence and intensity of ectoparasitism affects the physiological condition of young eagles, and changes to the landscape in southwestern Idaho may reduce the ability of eagles to ‘defend’ their nests from the effects of ectoparasitism with aromatic plants. Given the projections of current climate trends, continued monitoring of the effects of disease and ectoparasites on golden eagle populations will be important for future conservation

Correlates of Immune Defenses in Golden Eagle Nestlings

An individual’s investment in constitutive immune defenses depends on both intrinsic and extrinsic factors. We examined how Leucocytozoon parasite presence, body condition (scaled mass), heterophil-to-lymphocyte (H:L) ratio, sex, and age affected immune defenses in golden eagle (Aquila chrysaetos) nestlings from three regions: California, Oregon, and Idaho. We quantified hemolytic-complement activity and bacterial killing ability, two measures of constitutive immunity. Body condition and age did not affect immune defenses. However, eagles with lower H:L ratios had lower complement activity, corroborating other findings that animals in better condition sometimes invest less in constitutive immunity. In addition, eagles with Leucocytozoon infections had higher concentrations of circulating complement proteins but not elevated opsonizing proteins for all microbes, and eagles from Oregon had significantly higher constitutive immunity than those from California or Idaho. We posit that Oregon eagles might have elevated immune defenses because they are exposed to more endoparasites than eagles from California or Idaho, and our results confirmed that the OR region has the highest rate of Leucocytozoon infections. Our study examined immune function in a free-living, long-lived raptor species, whereas most avian ecoimmunological research focuses on passerines. Thus, our research informs a broad perspective regarding the evolutionary and environmental pressures on immune function in birds

Visualizing Qualitative Data: Creative Approaches for Analyzing and Demonstrating Lively Data from Diverse Learning Settings

This structured poster session aims to showcase novel approaches of qualitativelyanalyzing and communicating lively data—data that is complex, nuanced, multimodal, and multi-voiced. Such data is rich but also messy, often defying the traditional text-based forms of description and presentation. Therefore, the session pairs creative techniques and methods to analyze, triangulate, and/or visualize qualitative findings across multiple data sources (e.g., video, digital and physical spaces, participant artifacts, and patterns of movement) from diverse learning contexts (e.g., museums, libraries, outdoor spaces, and classrooms)—beyond showing transcriptions. The visual format of the session supports our goal of sharing and communicating rich data stories for further discussion with diverse audiences

A novel method of anatomical landmark selection for rib cage 3D reconstruction from biplanar radiography

Methods to reconstruct anatomical structures in 3D are gaining interest in medicine because they give access to quantitative information on the patient’s geometry. However, these methods are user-dependent and require a trained operator, which is time consuming and a source of error and unreliability. The aim of this work was to validate a novel method of landmark selection to perform the 3D reconstruction of the rib cage from biplanar calibrated radiographies. The method uses digital painting for digitization of anatomical landmarks (eight ribs midlines, posterior extrema, sternum) to build a first estimate of the 3D ribcage geometry. Twenty scoliotic patients were included (Cobb angle: 43° ± 11°) and their ribcage was reconstructed twice with the proposed method by four trained operators. Measurement reproducibility was similar to previously validated methods. Uncertainty (95% CI) was 2.3° for the rib hump measurement, 9.7 mm and 3.8 mm for maximal antero-posterior and lateral diameter, 395 cm3 for ribcage volume. The method was qualitatively considered more user-friendly than previous versions, although it still requires a trained operator, and it took approximately 2 minutes of manual digitization. The new method should facilitate diffusion of 3D quantitative analysis of ribcage in clinical routine

Dissecting the molecular organization of the translocon-associated protein complex

In eukaryotic cells, one-third of all proteins must be transported across or inserted into the endoplasmic reticulum (ER) membrane by the ER protein translocon. The translocon-associated protein (TRAP) complex is an integral component of the translocon, assisting the Sec61 protein-conducting channel by regulating signal sequence and transmembrane helix insertion in a substrate-dependent manner. Here we use cryo-electron tomography (CET) to study the structure of the native translocon in evolutionarily divergent organisms and disease-linked TRAP mutant fibroblasts from human patients. The structural differences detected by subtomogram analysis form a basis for dissecting the molecular organization of the TRAP complex. We assign positions to the four TRAP subunits within the complex, providing insights into their individual functions. The revealed molecular architecture of a central translocon component advances our understanding of membrane protein biogenesis and sheds light on the role of TRAP in human congenital disorders of glycosylation

The effects of linkage disequilibrium in large scale SNP datasets for MDR

<p>Abstract</p> <p>Background</p> <p>In the analysis of large-scale genomic datasets, an important consideration is the power of analytical methods to identify accurate predictive models of disease. When trying to assess sensitivity from such analytical methods, a confounding factor up to this point has been the presence of linkage disequilibrium (LD). In this study, we examined the effect of LD on the sensitivity of the Multifactor Dimensionality Reduction (MDR) software package.</p> <p>Results</p> <p>Four relative amounts of LD were simulated in multiple one- and two-locus scenarios for which the position of the functional SNP(s) within LD blocks varied. Simulated data was analyzed with MDR to determine the sensitivity of the method in different contexts, where the sensitivity of the method was gauged as the number of times out of 100 that the method identifies the correct one- or two-locus model as the best overall model. As the amount of LD increases, the sensitivity of MDR to detect the correct functional SNP drops but the sensitivity to detect the disease signal and find an indirect association increases.</p> <p>Conclusions</p> <p>Higher levels of LD begin to confound the MDR algorithm and lead to a drop in sensitivity with respect to the identification of a direct association; it does not, however, affect the ability to detect indirect association. Careful examination of the solution models generated by MDR reveals that MDR can identify loci in the correct LD block; though it is not always the functional SNP. As such, the results of MDR analysis in datasets with LD should be carefully examined to consider the underlying LD structure of the dataset.</p

Technology and the dis-placing of learning in educational futures

Common visions of online education entail radically re-configuring the experience of learning: a technological displacement from the spatial order of classrooms into the more diffuse arena of digital networks. One assumption seems to be that the very spatial order of classrooms creates an undesirably rigid sense of place for schooling, one that is depressingly impervious to change; and that the attendant solution is to escape the realm of the ‘physical’ altogether – into an online realm more supportive of collaboration and free of face-the-front conventions. In the present paper we seek to challenge this oppositional view. We consider several ways in which digital technology can restructure the traditional spaces of educational practice, and identify design dynamics that may be neglected in the wake of ‘virtualisation’. Discussion first highlights two theoretical perspectives that will inform many such designs: namely, situativity and sociality in learning. Three examples are then provided of how digital technology can intersect with learning space design to create novel interpersonal frameworks for learning and to destabilise conventional senses of ‘place’ in those settings. The examples concern, respectively, the organisation of collaborative, expository, and community-based social structures for learning. Those examples represent an illustrative counterpoint to models of online schooling and illustrate a potentially productive synergy between the opportunities afforded by digital technologies, the desires of those who wish to dis-place learning online, and a well-established interest in learning space design

Correction of fragile X syndrome in mice

SummaryFragile X syndrome (FXS) is the most common form of heritable mental retardation and the leading identified cause of autism. FXS is caused by transcriptional silencing of the FMR1 gene that encodes the fragile X mental retardation protein (FMRP), but the pathogenesis of the disease is unknown. According to one proposal, many psychiatric and neurological symptoms of FXS result from unchecked activation of mGluR5, a metabotropic glutamate receptor. To test this idea we generated Fmr1 mutant mice with a 50% reduction in mGluR5 expression and studied a range of phenotypes with relevance to the human disorder. Our results demonstrate that mGluR5 contributes significantly to the pathogenesis of the disease, a finding that has significant therapeutic implications for fragile X and related developmental disorders