66 research outputs found

    Reconstructing Vindonissa as a living document – A case-study of digital reconstruction for output to pre-rendered and real-time applications

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    The legion camp “Vindonissa” in Switzerland is considered one of the most important roman sites north of the alps. Research there has been going on for over a century and reconstructive drawings have always been a way to showcase scientific findings of the site, the earliest of them dating back as far as 1909. In 2015, it was decided to produce a new series of illustrations. The whole camp and its surrounding settlements had to be constructed as hand-generated 3D models, allowing for quick changes during the reconstructive process and flexibility in future adaptations. Topographical data, archaeological plans as well as building profiles provided by experts were the basis for the model. The main focus was on a general impression of the camp and not on individual buildings but some landmarks as the newly postulated circus were crafted with a higher level of detail as they are the topic of scientific discourse and it helps the discussion if they have a certain fidelity. The circus also serves as a good example for the value of the imaging process in research: Only after trying to fit it into the topography it was noted that it would overlap with a street that was previously thought to run through this area. In the discussion between archaeologists and illustrators a new path for the street was chosen that fits into the landscape and is scientifically acceptable. The new series of illustrations was originally published in the annual report of the archaeological society Vindonissa. The resulting model represents the current state of research but mainly serves as a starting point for future discussion: All buildings are constructed so that they can easily be adapted for real-time use and a Virtual Reality application is the logical next step for its use.

    Gene Transfer Agent Promotes Evolvability within the Fittest Subpopulation of a Bacterial Pathogen

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    The Bartonella gene transfer agent (BaGTA) is an archetypical example for domestication of a phage-derived element to permit high-frequency genetic exchange in bacterial populations. Here we used multiplexed transposon sequencing (TnSeq) and single-cell reporters to globally define the core components and transfer dynamics of BaGTA. Our systems-level analysis has identified inner- and outer-circle components of the BaGTA system, including 55 regulatory components, as well as an additional 74 and 107 components mediating donor transfer and recipient uptake functions. We show that the stringent response signal guanosine-tetraphosphate (ppGpp) restricts BaGTA induction to a subset of fast-growing cells, whereas BaGTA particle uptake depends on a functional Tol-Pal trans-envelope complex that mediates outer-membrane invagination upon cell division. Our findings suggest that Bartonella evolved an efficient strategy to promote genetic exchange within the fittest subpopulation while disfavoring exchange of deleterious genetic information, thereby facilitating genome integrity and rapid host adaptation

    Increasing awareness of climate change with immersive virtual reality

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    Previous research has shown that immersive virtual reality (VR) is a suitable tool for visualizing the consequences of climate change. The aim of the present study was to investigate whether visualization in VR has a stronger influence on climate change awareness and environmental attitudes compared to traditional media. Furthermore, it was examined how realistic a VR experience has to be in order to have an effect. The VR experience consisted of a model of the Aletsch glacier (Switzerland) melting over the course of 220 years. Explicit measurements (new environmental paradigm NEP, climate change scepticism, and nature relatedness) and an implicit measurement (implicit association test) were collected before and after the VR intervention and compared to three different non-VR control conditions (video, images with text, and plain text). In addition, the VR environment was varied in terms of degrees of realism and sophistication (3 conditions: abstract visualization, less sophisticated realistic visualization, more sophisticated realistic visualization). The six experimental conditions (3 VR conditions, three control conditions) were modeled as mixed effects, with VR versus control used as a fixed effect in a mixed effects modeling framework. Across all six conditions, environmental awareness (NEP) was higher after the participants (N = 142) had been confronted with the glacier melting, while no differences were found for nature relatedness and climate change scepticism before and after the interventions. There was no significant difference between VR and control conditions for any of the four measurements. Nevertheless, contrast analyses revealed that environmental awareness increased significantly only for the VR but not for the control conditions, suggesting that VR is more likely to lead to attitude change. Our results show that exposure to VR environments successfully increased environmental awareness independently of the design choices, suggesting that even abstract and less sophisticated VR environment designs may be sufficient to increase pro-environmental attitudes

    Bacterial rotary export ATPases are allosterically regulated by the nucleotide second messenger cyclic-di-GMP

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    The widespread second messenger molecule cyclic di-GMP (cdG) regulates the transition from motile and virulent lifestyles to sessile, biofilm-forming ones in a wide range of bacteria. Many pathogenic and commensal bacterial-host interactions are known to be controlled by cdG signaling. Although the biochemistry of cyclic dinucleotide metabolism is well understood, much remains to be discovered about the downstream signaling pathways that induce bacterial responses upon cdG binding. As part of our ongoing research into the role of cdG signaling in plant-associated Pseudomonas species, we carried out an affinity capture screen for cdG binding proteins in the model organism Pseudomonas fluorescens SBW25. The flagella export AAA+ ATPase FliI was identified as a result of this screen and subsequently shown to bind specifically to the cdG molecule, with a KD in the low micromolar range. The interaction between FliI and cdG appears to be very widespread. In addition to FliI homologs from diverse bacterial species, high affinity binding was also observed for the type III secretion system homolog HrcN and the type VI ATPase ClpB2. The addition of cdG was shown to inhibit FliI and HrcN ATPase activity in vitro. Finally, a combination of site-specific mutagenesis, mass spectrometry, and in silico analysis was used to predict that cdG binds to FliI in a pocket of highly conserved residues at the interface between two FliI subunits. Our results suggest a novel, fundamental role for cdG in controlling the function of multiple important bacterial export pathways, through direct allosteric control of export ATPase proteins

    The Antioxidant Role of Xanthurenic Acid in the Aedes aegypti Midgut during Digestion of a Blood Meal

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    In the midgut of the mosquito Aedes aegypti, a vector of dengue and yellow fever, an intense release of heme and iron takes place during the digestion of a blood meal. Here, we demonstrated via chromatography, light absorption and mass spectrometry that xanthurenic acid (XA), a product of the oxidative metabolism of tryptophan, is produced in the digestive apparatus after the ingestion of a blood meal and reaches milimolar levels after 24 h, the period of maximal digestive activity. XA formation does not occur in the White Eye (WE) strain, which lacks kynurenine hydroxylase and accumulates kynurenic acid. The formation of XA can be diminished by feeding the insect with 3,4-dimethoxy-N-[4-(3-nitrophenyl)thiazol-2-yl] benzenesulfonamide (Ro-61-8048), an inhibitor of XA biosynthesis. Moreover, XA inhibits the phospholipid oxidation induced by heme or iron. A major fraction of this antioxidant activity is due to the capacity of XA to bind both heme and iron, which occurs at a slightly alkaline pH (7.5-8.0), a condition found in the insect midgut. The midgut epithelial cells of the WE mosquito has a marked increase in occurrence of cell death, which is reversed to levels similar to the wild type mosquitoes by feeding the insects with blood supplemented with XA, confirming the protective role of this molecule. Collectively, these results suggest a new role for XA as a heme and iron chelator that provides protection as an antioxidant and may help these animals adapt to a blood feeding habit

    Behavioral responses of terrestrial mammals to COVID-19 lockdowns

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    COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.acceptedVersio

    Behavioral responses of terrestrial mammals to COVID-19 lockdowns

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    COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.acceptedVersio

    Author Correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases

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    Emmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article

    Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases

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    Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r =-0.62, P = 5.30 × 10-5) but not between CCT and primary open-angle glaucoma (r =-0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation

    Meta-analysis of genome-wide association studies identifies novel loci that influence cupping and the glaucomatous process

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    Glaucoma is characterized by irreversible optic nerve degeneration and is the most frequent cause of irreversible blindness worldwide. Here, the International Glaucoma Genetics Consortium conducts a meta-analysis of genome-wide association studies of vertical cup-disc ratio (VCDR), an important disease-related optic nerve parameter. In 21,094 individuals of European ancestry and 6,784 individuals of Asian ancestry, we identify 10 new loci associated with variation in VCDR. In a separate risk-score analysis of five case-control studies, Caucasians in the highest quintile have a 2.5-fold increased risk of primary open-angle glaucoma as compared with those in the lowest quintile. This study has more than doubled the known loci associated with optic disc cupping and will allow greater understanding of mechanisms involved in this common blinding condition
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