202 research outputs found

    Towards an optimal design of target for tsetse control: comparisons of novel targets for the control of palpalis group tsetse in West Africa

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    Background: Tsetse flies of the Palpalis group are the main vectors of sleeping sickness in Africa. Insecticide impregnated targets are one of the most effective tools for control. However, the cost of these devices still represents a constraint to their wider use. The objective was therefore to improve the cost effectiveness of currently used devices. Methodology/Principal Findings: Experiments were performed on three tsetse species, namely Glossina palpalis gambiensis and G. tachinoides in Burkina Faso and G. p. palpalis in Côte d'Ivoire. The 1×1 m2 black blue black target commonly used in W. Africa was used as the standard, and effects of changes in target size, shape, and the use of netting instead of black cloth were measured. Regarding overall target shape, we observed that horizontal targets (i.e. wider than they were high) killed 1.6-5x more G. p. gambiensis and G. tachinoides than vertical ones (i.e. higher than they were wide) (P<0.001). For the three tsetse species including G. p. palpalis, catches were highly correlated with the size of the target. However, beyond the size of 0.75 m, there was no increase in catches. Replacing the black cloth of the target by netting was the most cost efficient for all three species. Conclusion/Significance: Reducing the size of the current 1*1 m black-blue-black target to horizontal designs of around 50 cm and replacing black cloth by netting will improve cost effectiveness six-fold for both G. p. gambiensis and G. tachinoides. Studying the visual responses of tsetse to different designs of target has allowed us to design more cost-effective devices for the effective control of sleeping sickness and animal trypanosomiasis in Africa

    Predicting consumer biomass, size-structure, production, catch potential, responses to fishing and associated uncertainties in the world's marine ecosystems

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    Existing estimates of fish and consumer biomass in the world’s oceans are disparate. This creates uncertainty about the roles of fish and other consumers in biogeochemical cycles and ecosystem processes, the extent of human and environmental impacts and fishery potential. We develop and use a size-based macroecological model to assess the effects of parameter uncertainty on predicted consumer biomass, production and distribution. Resulting uncertainty is large (e.g. median global biomass 4.9 billion tonnes for consumers weighing 1 g to 1000 kg; 50% uncertainty intervals of 2 to 10.4 billion tonnes; 90% uncertainty intervals of 0.3 to 26.1 billion tonnes) and driven primarily by uncertainty in trophic transfer efficiency and its relationship with predator-prey body mass ratios. Even the upper uncertainty intervals for global predictions of consumer biomass demonstrate the remarkable scarcity of marine consumers, with less than one part in 30 million by volume of the global oceans comprising tissue of macroscopic animals. Thus the apparently high densities of marine life seen in surface and coastal waters and frequently visited abundance hotspots will likely give many in society a false impression of the abundance of marine animals. Unexploited baseline biomass predictions from the simple macroecological model were used to calibrate a more complex size- and trait-based model to estimate fisheries yield and impacts. Yields are highly dependent on baseline biomass and fisheries selectivity. Predicted global sustainable fisheries yield increases ≈4 fold when smaller individuals (< 20 cm from species of maximum mass < 1kg) are targeted in all oceans, but the predicted yields would rarely be accessible in practice and this fishing strategy leads to the collapse of larger species if fishing mortality rates on different size classes cannot be decoupled. Our analyses show that models with minimal parameter demands that are based on a few established ecological principles can support equitable analysis and comparison of diverse ecosystems. The analyses provide insights into the effects of parameter uncertainty on global biomass and production estimates, which have yet to be achieved with complex models, and will therefore help to highlight priorities for future research and data collection. However, the focus on simple model structures and global processes means that non-phytoplankton primary production and several groups, structures and processes of ecological and conservation interest are not represented. Consequently, our simple models become increasingly less useful than more complex alternatives when addressing questions about food web structure and function, biodiversity, resilience and human impacts at smaller scales and for areas closer to coasts

    Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment

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    The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R2γR_{2\gamma}, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of 20°\approx 20\degree to 80°80\degree. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved GEM and MWPC detectors at 12°12\degree, as well as symmetric M{\o}ller/Bhabha calorimeters at 1.29°1.29\degree. A total integrated luminosity of 4.5~fb1^{-1} was collected. In the extraction of R2γR_{2\gamma}, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R2γR_{2\gamma}, presented here for a wide range of virtual photon polarization 0.456<ϵ<0.9780.456<\epsilon<0.978, are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.Comment: 5 pages, 3 figures, 2 table

    Expression of multidrug resistance markers ABCB1 (MDR-1/P-gp) and ABCC1 (MRP-1) in renal cell carcinoma

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    Background: Renal cancer patients respond poorly to conventional chemotherapy, this unresponsiveness may be attributable to multidrug resistance (MDR). The mechanisms of MDR in renal cancer are not fully understood and the specific contribution of ABC transporter proteins which have been implicated in the chemoresistance of various cancers has not been fully defined in this disease. Methods: The aim of this prospective study was to analyse by immunohistochemistry the expression of two of these transporter efflux pumps, namely MDR-1/P-gp (ABCB1) and MRP-1 (ABCC1) in archival material from 113 renal carcinoma patients. Results: In the largest study of its kind, results presented here show 100% of cases stained positively for P-gp and MRP-1 protein expression. Conclusion: However, although these findings do not prove a causal role, the high frequency of tumours expressing these efflux pumps suggests that they may be important contributors to the chemoresistance of this tumour type

    Impact of Carnivory on Human Development and Evolution Revealed by a New Unifying Model of Weaning in Mammals

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    Our large brain, long life span and high fertility are key elements of human evolutionary success and are often thought to have evolved in interplay with tool use, carnivory and hunting. However, the specific impact of carnivory on human evolution, life history and development remains controversial. Here we show in quantitative terms that dietary profile is a key factor influencing time to weaning across a wide taxonomic range of mammals, including humans. In a model encompassing a total of 67 species and genera from 12 mammalian orders, adult brain mass and two dichotomous variables reflecting species differences regarding limb biomechanics and dietary profile, accounted for 75.5%, 10.3% and 3.4% of variance in time to weaning, respectively, together capturing 89.2% of total variance. Crucially, carnivory predicted the time point of early weaning in humans with remarkable precision, yielding a prediction error of less than 5% with a sample of forty-six human natural fertility societies as reference. Hence, carnivory appears to provide both a necessary and sufficient explanation as to why humans wean so much earlier than the great apes. While early weaning is regarded as essentially differentiating the genus Homo from the great apes, its timing seems to be determined by the same limited set of factors in humans as in mammals in general, despite some 90 million years of evolution. Our analysis emphasizes the high degree of similarity of relative time scales in mammalian development and life history across 67 genera from 12 mammalian orders and shows that the impact of carnivory on time to weaning in humans is quantifiable, and critical. Since early weaning yields shorter interbirth intervals and higher rates of reproduction, with profound effects on population dynamics, our findings highlight the emergence of carnivory as a process fundamentally determining human evolution

    Mitochondrial Ca2+ Overload Underlies Aβ Oligomers Neurotoxicity Providing an Unexpected Mechanism of Neuroprotection by NSAIDs

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    Dysregulation of intracellular Ca2+ homeostasis may underlie amyloid β peptide (Aβ) toxicity in Alzheimer's Disease (AD) but the mechanism is unknown. In search for this mechanism we found that Aβ1–42 oligomers, the assembly state correlating best with cognitive decline in AD, but not Aβ fibrils, induce a massive entry of Ca2+ in neurons and promote mitochondrial Ca2+ overload as shown by bioluminescence imaging of targeted aequorin in individual neurons. Aβ oligomers induce also mitochondrial permeability transition, cytochrome c release, apoptosis and cell death. Mitochondrial depolarization prevents mitochondrial Ca2+ overload, cytochrome c release and cell death. In addition, we found that a series of non-steroidal anti-inflammatory drugs (NSAIDs) including salicylate, sulindac sulfide, indomethacin, ibuprofen and R-flurbiprofen depolarize mitochondria and inhibit mitochondrial Ca2+ overload, cytochrome c release and cell death induced by Aβ oligomers. Our results indicate that i) mitochondrial Ca2+ overload underlies the neurotoxicity induced by Aβ oligomers and ii) inhibition of mitochondrial Ca2+ overload provides a novel mechanism of neuroprotection by NSAIDs against Aβ oligomers and AD

    ZNF280BY and ZNF280AY: autosome derived Y-chromosome gene families in Bovidae

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    <p>Abstract</p> <p>Background</p> <p>Recent progress in exploring the Y-chromosome gene content in humans, mice and cats have suggested that "autosome-to-Y" transposition of the male fertility genes is a recurrent theme during the mammalian Y-chromosome evolution. These transpositions are lineage-dependent. The purpose of this study is to investigate the lineage-specific Y-chromosome genes in bovid.</p> <p>Results</p> <p>We took a direct testis cDNA selection strategy and discovered two novel gene families, <it>ZNF280BY </it>and <it>ZNF280AY</it>, on the bovine (<it>Bos taurus</it>) Y-chromosome (BTAY), which originated from the transposition of a gene block on the bovine chromosome 17 (BTA17) and subsequently amplified. Approximately 130 active <it>ZNF280BY </it>loci (and ~240 pseudogenes) and ~130 pseudogenized <it>ZNF280AY </it>copies are present over the majority of the male-specific region (MSY). Phylogenetic analysis indicated that both gene families fit with the "birth-and-death" model of evolution. The active <it>ZNF280BY </it>loci share high sequence similarity and comprise three major genomic structures, resulted from insertions/deletions (indels). Assembly of a 1.2 Mb BTAY sequence in the MSY ampliconic region demonstrated that <it>ZNF280BY </it>and <it>ZNF280AY</it>, together with <it>HSFY </it>and <it>TSPY </it>families, constitute the major elements within the repeat units. The <it>ZNF280BY </it>gene family was found to express in different developmental stages of testis with sense RNA detected in all cell types of the seminiferous tubules while the antisense RNA detected only in the spermatids. Deep sequencing of the selected cDNAs revealed that different loci of <it>ZNF280BY </it>were differentially expressed up to 60-fold. Interestingly, different copies of the <it>ZNF280AY </it>pseudogenes were also found to differentially express up to 10-fold. However, expression level of the <it>ZNF280AY </it>pseudogenes was almost 6-fold lower than that of the <it>ZNF280BY </it>genes. <it>ZNF280BY </it>and <it>ZNF280AY </it>gene families are present in bovid, but absent in other mammalian lineages.</p> <p>Conclusions</p> <p><it>ZNF280BY </it>and <it>ZNF280AY </it>are lineage-specific, multi-copy Y-gene families specific to <it>Bovidae</it>, and are derived from the transposition of an autosomal gene block. The temporal and spatial expression patterns of <it>ZNF280BY</it>s in testis suggest a role in spermatogenesis. This study offers insights into the genomic organization of the bovine MSY and gene regulation in spermatogenesis, and provides a model for studying evolution of multi-copy gene families in mammals.</p

    Linking Proteomic and Transcriptional Data through the Interactome and Epigenome Reveals a Map of Oncogene-induced Signaling

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    Cellular signal transduction generally involves cascades of post-translational protein modifications that rapidly catalyze changes in protein-DNA interactions and gene expression. High-throughput measurements are improving our ability to study each of these stages individually, but do not capture the connections between them. Here we present an approach for building a network of physical links among these data that can be used to prioritize targets for pharmacological intervention. Our method recovers the critical missing links between proteomic and transcriptional data by relating changes in chromatin accessibility to changes in expression and then uses these links to connect proteomic and transcriptome data. We applied our approach to integrate epigenomic, phosphoproteomic and transcriptome changes induced by the variant III mutation of the epidermal growth factor receptor (EGFRvIII) in a cell line model of glioblastoma multiforme (GBM). To test the relevance of the network, we used small molecules to target highly connected nodes implicated by the network model that were not detected by the experimental data in isolation and we found that a large fraction of these agents alter cell viability. Among these are two compounds, ICG-001, targeting CREB binding protein (CREBBP), and PKF118–310, targeting β-catenin (CTNNB1), which have not been tested previously for effectiveness against GBM. At the level of transcriptional regulation, we used chromatin immunoprecipitation sequencing (ChIP-Seq) to experimentally determine the genome-wide binding locations of p300, a transcriptional co-regulator highly connected in the network. Analysis of p300 target genes suggested its role in tumorigenesis. We propose that this general method, in which experimental measurements are used as constraints for building regulatory networks from the interactome while taking into account noise and missing data, should be applicable to a wide range of high-throughput datasets.National Science Foundation (U.S.) (DB1-0821391)National Institutes of Health (U.S.) (Grant U54-CA112967)National Institutes of Health (U.S.) (Grant R01-GM089903)National Institutes of Health (U.S.) (P30-ES002109
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