383 research outputs found

    U-Pb zircon ages of the Wildhorse gneiss, Pioneer Mountains, south-central Idaho, and tectonic implications

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    The gneiss complex of Wildhorse Creek (Wildhorse gneiss) forms the central component of the lowest structural plate in the Pioneer metamorphic core complex of south-central Idaho. The oldest rock in the complex is a felsic ortho-gneiss, with Neoarchean U-Pb magmatic zircon ages of 2.60-2.67 Ga. The ortho-gneiss overlaps in age and is interpreted to be part of the Grouse Creek block of the Albion Mountains to the south. This Archean metagranitoid is structurally interleaved with paragneiss containing quartzite and calc-silicate rock. Structurally below the orthogneiss, some quartzites have multiple concordant populations of detrital-zircon grains as young as ca. 1700 Ma, while others have no zircon grains younger than ca. 2500 Ma. Structurally above the Archean gneiss is a heterogeneous paragneiss that contains calc-silicate and quartzitic rocks with detrital zircons as young as ca. 1460 Ma. Amphibolite in this unit contains zircons dated at ca. 1850 Ma, indicating that this rock can be no older than that and implying considerable structural complexity. The upper part of the Wildhorse gneiss contains metaquartzites bearing zircons as young as ca. 1400 Ma. The protolith of this paragneiss is interpreted as the southernmost exposures of the Lemhi subbasin of the Mesoproterozoic Belt Supergroup. The upper Wildhorse gneiss includes ca. 695 Ma intrusive orthogneiss that is coeval with Neoproterozoic rift-related volcanic or intrusive rocks near Pocatello, House Mountain, and Edwardsburg, Idaho. This Cryogenian meta-intrusive rock is the likely source of the 650-710 Ma detrital-zircon population in the Big Lost River that drains the core complex. Initial eHf values from 675 Ma zircons are between 3.4 and -2.4, suggesting the granitoids had a mixed source in both continental crust and juvenile mantle.This research was supported by National Science Foundation grants EAR 05-10980 and 08-38425 and U.S. Geological Survey grant G14AC00136. Logistical support was provided by the Idaho State University Geology field camp at Lost River Field Station

    Design and implementation of the OFELIA FP7 facility: The European OpenFlow testbed

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    The growth of the Internet in terms of number of devices, the number of networks associated to each device and the mobility of devices and users makes the operation and management of the Internet network infrastructure a very complex challenge. In order to address this challenge, innovative solutions and ideas must be tested and evaluated in real network environments and not only based on simulations or laboratory setups. OFELIA is an European FP7 project and its main objective is to address the aforementioned challenge by building and operating a multi-layer, multi-technology and geographically distributed Future Internet testbed facility, where the network itself is precisely controlled and programmed by the experimenter using the emerging OpenFlow technology. This paper reports on the work done during the first half of the project, the lessons learned as well as the key advantages of the OFELIA facility for developing and testing new networking ideas. An overview on the challenges that have been faced on the design and implementation of the testbed facility is described, including the OFELIA Control Framework testbed management software. In addition, early operational experience of the facility since it was opened to the general public, providing five different testbeds or islands, is described

    Evolutionary Toxicology: Population-Level Effects of Chronic Contaminant Exposure on the Marsh Frogs (Rana ridibunda) of Azerbaijan

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    We used molecular methods and population genetic analyses to study the effects of chronic contaminant exposure in marsh frogs from Sumgayit, Azerbaijan. Marsh frogs inhabiting wetlands in Sumgayit are exposed to complex mixtures of chemical contaminants, including petroleum products, pesticides, heavy metals, and many other industrial chemicals. Previous results documented elevated estimates of genetic damage in marsh frogs from the two most heavily contaminated sites. Based on mitochondrial DNA (mtDNA) control region sequence data, the Sumgayit region has reduced levels of genetic diversity, likely due to environmental degradation. The Sumgayit region also acts as an ecological sink, with levels of gene flow into the region exceeding gene flow out of the region. Additionally, localized mtDNA heteroplasmy and diversity patterns suggest that one of the most severely contaminated sites in Sumgayit is acting as a source of new mutations resulting from an increased mutation rate. This study provides an integrated method for assessing the cumulative population impacts of chronic contaminant exposure by studying both population genetic and evolutionary effects

    Geometrically defined environments direct cell division rate and subcellular YAP localization in single mouse embryonic stem cells

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    Mechanotransduction via yes-associated protein (YAP) is a central mechanism for decision-making in mouse embryonic stem cells (mESCs). Nuclear localization of YAP is tightly connected to pluripotency and increases the cell division rate (CDR). How the geometry of the extracellular environment influences mechanotransduction, thereby YAP localization, and decision-making of single isolated mESCs is largely unknown. To investigate this relation, we produced well-defined 2D and 2.5D microenvironments and monitored CDR and subcellular YAP localization in single mESCs hence excluding cell–cell interactions. By systematically varying size and shape of the 2D and 2.5D substrates we observed that the geometry of the growth environment affects the CDR. Whereas CDR increases with increasing adhesive area in 2D, CDR is highest in small 2.5D micro-wells. Here, mESCs attach to all four walls and exhibit a cross-shaped cell and nuclear morphology. This observation indicates that changes in cell shape are linked to a high CDR. Inhibition of actomyosin activity abrogate these effects. Correspondingly, nuclear YAP localization decreases in inhibitor treated cells, suggesting a relation between cell shape, intracellular forces, and cell division rate. The simplicity of our system guarantees high standardization and reproducibility for monitoring stem cell reactions and allows addressing a variety of fundamental biological questions on a single cell level

    Immune Evasion by Yersinia enterocolitica: Differential Targeting of Dendritic Cell Subpopulations In Vivo

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    CD4+ T cells are essential for the control of Yersinia enterocolitica (Ye) infection in mice. Ye can inhibit dendritic cell (DC) antigen uptake and degradation, maturation and subsequently T-cell activation in vitro. Here we investigated the effects of Ye infection on splenic DCs and T-cell proliferation in an experimental mouse infection model. We found that OVA-specific CD4+ T cells had a reduced potential to proliferate when stimulated with OVA after infection with Ye compared to control mice. Additionally, proliferation of OVA-specific CD4+ T cells was markedly reduced when cultured with splenic CD8α+ DCs from Ye infected mice in the presence of OVA. In contrast, T-cell proliferation was not impaired in cultures with CD4+ or CD4−CD8α− DCs isolated from Ye infected mice. However, OVA uptake and degradation as well as cytokine production were impaired in CD8α+ DCs, but not in CD4+ and CD4−CD8α− DCs after Ye infection. Pathogenicity factors (Yops) from Ye were most frequently injected into CD8α+ DCs, resulting in less MHC class II and CD86 expression than on non-injected CD8α+ DCs. Three days post infection with Ye the number of splenic CD8α+ and CD4+ DCs was reduced by 50% and 90%, respectively. The decreased number of DC subsets, which was dependent on TLR4 and TRIF signaling, was the result of a faster proliferation and suppressed de novo DC generation. Together, we show that Ye infection negatively regulates the stimulatory capacity of some but not all splenic DC subpopulations in vivo. This leads to differential antigen uptake and degradation, cytokine production, cell loss, and cell death rates in various DC subpopulations. The data suggest that these effects might be caused directly by injection of Yops into DCs and indirectly by affecting the homeostasis of CD4+ and CD8α+ DCs. These events may contribute to reduced T-cell proliferation and immune evasion of Ye

    MALDI mass spectrometry imaging - Diagnostic pathways and metabolites for renal tumor entities

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    BACKGROUND Correct tumor subtyping of primary renal tumors is essential for treatment decision in daily routine. Most of the tumors can be classified on morphology alone. Nevertheless, some diagnoses are difficult and further investigations are needed for correct tumor subtyping. Beside histochemical investigations high mass resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can detect new diagnostic biomarkers and hence improve the diagnostic. PATIENTS AND METHODS Formalin-fixed paraffin embedded (FFPE) tissue specimens from clear cell renal cell carcinoma (ccRCC, n=552), papillary RCC (pRCC, n=122), chromophobe RCC (chRCC, n=108) and renal Oncocytoma (rO, n=71) were analyzed by high mass resolution matrix-assisted laser desorption/ionization (MALDI) fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry imaging (MSI). SPACiAL pipeline was executed for automated co-registration of histological and molecular features. Pathway enrichment and pathway topology analysis were performed to determine significant differences between RCC subtypes. RESULTS We discriminated the four histological subtypes (ccRCC, pRCC, chRCC and rO) and established the subtype specific pathways and metabolic profiles. RO showed an enrichment of pentose phosphate, taurine and hypotaurine, glycerophospholipid, amino sugar and nucleotide sugar, fructose and mannose, glycine, serine and threonine pathways. ChRCC is defined by enriched pathways including the amino sugar and nucleotide sugar, fructose and mannose, glycerophospholipid, taurine and hypotaurine, glycine, serine and threonine pathways. Pyrimidine, amino sugar and nucleotide sugar, glycerophospholipid and glutathione pathways are enriched in ccRCC. Furthermore, we detected enriched phosphatidylinositol and glycerophospholipid pathways in pRCC. CONCLUSION In summary, we performed a classification system with a mean accuracy in tumor discrimination of 85,13%. Furthermore, we detected tumor specific biomarkers for the four most common primary renal tumors by MALDI-MSI. This method is a useful tool in differential diagnosis and in biomarker detection

    Yersinia enterocolitica Targets Cells of the Innate and Adaptive Immune System by Injection of Yops in a Mouse Infection Model

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    Yersinia enterocolitica (Ye) evades the immune system of the host by injection of Yersinia outer proteins (Yops) via a type three secretion system into host cells. In this study, a reporter system comprising a YopE-β-lactamase hybrid protein and a fluorescent staining sensitive to β-lactamase cleavage was used to track Yop injection in cell culture and in an experimental Ye mouse infection model. Experiments with GD25, GD25-β1A, and HeLa cells demonstrated that β1-integrins and RhoGTPases play a role for Yop injection. As demonstrated by infection of splenocyte suspensions in vitro, injection of Yops appears to occur randomly into all types of leukocytes. In contrast, upon infection of mice, Yop injection was detected in 13% of F4/80+, 11% of CD11c+, 7% of CD49b+, 5% of Gr1+ cells, 2.3% of CD19+, and 2.6% of CD3+ cells. Taking the different abundance of these cell types in the spleen into account, the highest total number of Yop-injected cells represents B cells, particularly CD19+CD21+CD23+ follicular B cells, followed by neutrophils, dendritic cells, and macrophages, suggesting a distinct cellular tropism of Ye. Yop-injected B cells displayed a significantly increased expression of CD69 compared to non-Yop-injected B cells, indicating activation of these cells by Ye. Infection of IFN-γR (receptor)- and TNFRp55-deficient mice resulted in increased numbers of Yop-injected spleen cells for yet unknown reasons. The YopE-β-lactamase hybrid protein reporter system provides new insights into the modulation of host cell and immune responses by Ye Yops

    Depletion of Dendritic Cells Enhances Innate Anti-Bacterial Host Defense through Modulation of Phagocyte Homeostasis

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    Dendritic cells (DCs) as professional antigen-presenting cells play an important role in the initiation and modulation of the adaptive immune response. However, their role in the innate immune response against bacterial infections is not completely defined. Here we have analyzed the role of DCs and their impact on the innate anti-bacterial host defense in an experimental infection model of Yersinia enterocolitica (Ye). We used CD11c-diphtheria toxin (DT) mice to deplete DCs prior to severe infection with Ye. DC depletion significantly increased animal survival after Ye infection. The bacterial load in the spleen of DC-depleted mice was significantly lower than that of control mice throughout the infection. DC depletion was accompanied by an increase in the serum levels of CXCL1, G-CSF, IL-1α, and CCL2 and an increase in the numbers of splenic phagocytes. Functionally, splenocytes from DC-depleted mice exhibited an increased bacterial killing capacity compared to splenocytes from control mice. Cellular studies further showed that this was due to an increased production of reactive oxygen species (ROS) by neutrophils. Adoptive transfer of neutrophils from DC-depleted mice into control mice prior to Ye infection reduced the bacterial load to the level of Ye-infected DC-depleted mice, suggesting that the increased number of phagocytes with additional ROS production account for the decreased bacterial load. Furthermore, after incubation with serum from DC-depleted mice splenocytes from control mice increased their bacterial killing capacity, most likely due to enhanced ROS production by neutrophils, indicating that serum factors from DC-depleted mice account for this effect. In summary, we could show that DC depletion triggers phagocyte accumulation in the spleen and enhances their anti-bacterial killing capacity upon bacterial infection

    The Intimin periplasmic domain mediates dimerisation and binding to peptidoglycan

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    Intimin and Invasin are prototypical inverse (Type Ve) autotransporters and important virulence factors of enteropathogenic Escherichia coli and Yersinia spp., respectively. In addition to a C-terminal extracellular domain and a β-barrel transmembrane domain, both proteins also contain a short N- terminal periplasmic domain that, in Intimin, includes a lysin motif (LysM), which is thought to mediate binding to peptidoglycan. We show that the periplasmic domain of Intimin – but not the shorter domain of Invasin – does bind to peptidoglycan both in vitro and in vivo, but only under acidic conditions. We present the solution structure of the Intimin LysM, which has an additional, potentially functionally relevant α-helix compared to other LysMs. In contrast to previous reports, we demonstrate that the periplasmic domain of Intimin mediates dimerisation. Our data suggests that the periplasmic domain contains two dimerisation interfaces. We further show that dimerisation and peptidoglycan binding are general features of LysM-containing inverse autotransporters. The periplasmic domain could be involved in autotransport, and peptidoglycan binding may aid in resisting mechanical and chemical stress during transit through the gastrointestinal tract
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