122 research outputs found

    The Circadian Clock Protein Timeless Regulates Phagocytosis of Bacteria in Drosophila

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    Survival of bacterial infection is the result of complex host-pathogen interactions. An often-overlooked aspect of these interactions is the circadian state of the host. Previously, we demonstrated that Drosophila mutants lacking the circadian regulatory proteins Timeless (Tim) and Period (Per) are sensitive to infection by S. pneumoniae. Sensitivity to infection can be mediated either by changes in resistance (control of microbial load) or tolerance (endurance of the pathogenic effects of infection). Here we show that Tim regulates resistance against both S. pneumoniae and S. marcescens. We set out to characterize and identify the underlying mechanism of resistance that is circadian-regulated. Using S. pneumoniae, we found that resistance oscillates daily in adult wild-type flies and that these oscillations are absent in Tim mutants. Drosophila have at least three main resistance mechanisms to kill high levels of bacteria in their hemolymph: melanization, antimicrobial peptides, and phagocytosis. We found that melanization is not circadian-regulated. We further found that basal levels of AMP gene expression exhibit time-of-day oscillations but that these are Tim-independent; moreover, infection-induced AMP gene expression is not circadian-regulated. We then show that phagocytosis is circadian-regulated. Wild-type flies exhibit up-regulated phagocytic activity at night; Tim mutants have normal phagocytic activity during the day but lack this night-time peak. Tim appears to regulate an upstream event in phagocytosis, such as bacterial recognition or activation of phagocytic hemocytes. Interestingly, inhibition of phagocytosis in wild type flies results in survival kinetics similar to Tim mutants after infection with S. pneumoniae. Taken together, these results suggest that loss of circadian oscillation of a specific immune function (phagocytosis) can have significant effects on long-term survival of infection

    Systematic meta-analyses and field synopsis of genetic association studies of violence and aggression

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    A large number of candidate gene studies for aggression and violence have been conducted. Successful identification of associations between genetic markers and aggression would contribute to understanding the neurobiology of antisocial behavior and potentially provide useful tools for risk prediction and therapeutic targets for high-risk groups of patients and offenders. We systematically reviewed the literature and assessed the evidence on genetic association studies of aggression and related outcomes in order to provide a field synopsis. We searched PubMed and Huge Navigator databases and sought additional data through reviewing reference lists and correspondence with investigators. Genetic association studies were included if outcome data on aggression or violent behavior either as a binary outcome or as a quantitative trait were provided. From 1331 potentially relevant investigations, 185 studies constituting 277 independent associations on 31 genes fulfilled the predetermined selection criteria. Data from variants investigated in three or more samples were combined in meta-analyses and potential sources of heterogeneity were investigated using subgroup analyses. In the primary analyses, which used relaxed inclusion criteria, we found no association between any polymorphism analyzed and aggression at the 5% level of significance. Subgroup analyses, including by severity of outcome, age group, characteristics of the sample and ethnicity, did not demonstrate any consistent findings. Current evidence does not support the use of such genes to predict dangerousness or as markers for therapeutic interventions

    The Synergistic Effect of Concomitant Schistosomiasis, Hookworm, and Trichuris Infections on Children's Anemia Burden

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    Polyparasitic infections have been recognized as the norm in many tropical developing countries, but the significance of this phenomenon for helminth-associated morbidities is largely unexplored. Earlier studies have suggested that multi-species, low-intensity parasitic infections were associated with higher odds of anemia among school-age children relative to their uninfected counterparts or those with one low-intensity infection. However, specific studies of the nature of interactions between helminth species in the mediation of helminth-associated morbidities are lacking. This study quantifies the extent to which polyparasitic infections have more than the sum of adverse effects associated with individual infections in the context of childhood anemia. This study found that the risk of anemia is amplified beyond the sum of risks for individual infections in children simultaneously exposed to 1) hookworm and schistosomiasis, and 2) hookworm and trichuris, and suggests that combined treatment for some geohelminth species and schistosomiasis could yield greater than additive benefits for the reduction of childhood anemia in helminth-endemic areas. However, more studies to understand the full range of interactions between parasitic species in their joint effects on helminth-associated morbidities will be necessary to better predict the impact of any future public health intervention

    Multi-criteria ranking of corporate distress prediction models: empirical evaluation and methodological contributions

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    YesAlthough many modelling and prediction frameworks for corporate bankruptcy and distress have been proposed, the relative performance evaluation of prediction models is criticised due to the assessment exercise using a single measure of one criterion at a time, which leads to reporting conflicting results. Mousavi et al. (Int Rev Financ Anal 42:64–75, 2015) proposed an orientation-free super-efficiency DEA-based framework to overcome this methodological issue. However, within a super-efficiency DEA framework, the reference benchmark changes from one prediction model evaluation to another, which in some contexts might be viewed as “unfair” benchmarking. In this paper, we overcome this issue by proposing a slacks-based context-dependent DEA (SBM-CDEA) framework to evaluate competing distress prediction models. In addition, we propose a hybrid crossbenchmarking- cross-efficiency framework as an alternative methodology for ranking DMUs that are heterogeneous. Furthermore, using data on UK firms listed on London Stock Exchange, we perform a comprehensive comparative analysis of the most popular corporate distress prediction models; namely, statistical models, under both mono criterion and multiple criteria frameworks considering several performance measures. Also, we propose new statistical models using macroeconomic indicators as drivers of distress

    Women, sport and new media technologies:Derby grrrls online

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    Sport has long been viewed as a public ‘good’ — a space for the creation and enactment of the ‘good, healthy citizen’. Yet this public ‘good’ has also been gendered masculine: competitive, public and ‘tough’, with women’s participation historically marginal to men’s. In Australia in recent years, the participation of women and girls has fluctuated, with decline or stagnation in more traditional organised sports (netball, basketball) and growth in other areas, such as roller derby and football. However, women’s sports are still largely invisible in the popular sport media. In this chapter we focus on roller derby as one particular women’s sport that has undergone a global revival, mobilised through ‘new’ youth-oriented media forms. We examine four diverse websites that form part of the ‘social web’ of derby: two official league sites, a blog and a Facebook group. The reinvention of roller derby is intimately connected to the alternative mediated spaces made possible by the social web. Roller derby players and organisers have used online spaces for various ends: to promote the sport community, to make visible the relations of power between those involved, to create and maintain boundaries of inclusion and exclusion within the sport, and to express ‘creative’ aspects of identity. This chapter provides examples of the strategies and tactics used to establish and maintain roller derby as a ‘women’s only’ sport and some of the challenges and possibilities inherent in this highly mediated space.No Full Tex

    Affective neuroscience of pleasure: reward in humans and animals

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