222 research outputs found

    Biodiversity Loss and the Taxonomic Bottleneck: Emerging Biodiversity Science

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    Human domination of the Earth has resulted in dramatic changes to global and local patterns of biodiversity. Biodiversity is critical to human sustainability because it drives the ecosystem services that provide the core of our life-support system. As we, the human species, are the primary factor leading to the decline in biodiversity, we need detailed information about the biodiversity and species composition of specific locations in order to understand how different species contribute to ecosystem services and how humans can sustainably conserve and manage biodiversity. Taxonomy and ecology, two fundamental sciences that generate the knowledge about biodiversity, are associated with a number of limitations that prevent them from providing the information needed to fully understand the relevance of biodiversity in its entirety for human sustainability: (1) biodiversity conservation strategies that tend to be overly focused on research and policy on a global scale with little impact on local biodiversity; (2) the small knowledge base of extant global biodiversity; (3) a lack of much-needed site-specific data on the species composition of communities in human-dominated landscapes, which hinders ecosystem management and biodiversity conservation; (4) biodiversity studies with a lack of taxonomic precision; (5) a lack of taxonomic expertise and trained taxonomists; (6) a taxonomic bottleneck in biodiversity inventory and assessment; and (7) neglect of taxonomic resources and a lack of taxonomic service infrastructure for biodiversity science. These limitations are directly related to contemporary trends in research, conservation strategies, environmental stewardship, environmental education, sustainable development, and local site-specific conservation. Today’s biological knowledge is built on the known global biodiversity, which represents barely 20% of what is currently extant (commonly accepted estimate of 10 million species) on planet Earth. Much remains unexplored and unknown, particularly in hotspots regions of Africa, South Eastern Asia, and South and Central America, including many developing or underdeveloped countries, where localized biodiversity is scarcely studied or described. ‘‘Backyard biodiversity’’, defined as local biodiversity near human habitation, refers to the natural resources and capital for ecosystem services at the grassroots level, which urgently needs to be explored, documented, and conserved as it is the backbone of sustainable economic development in these countries. Beginning with early identification and documentation of local flora and fauna, taxonomy has documented global biodiversity and natural history based on the collection of ‘‘backyard biodiversity’’ specimens worldwide. However, this branch of science suffered a continuous decline in the latter half of the twentieth century, and has now reached a point of potential demise. At present there are very few professional taxonomists and trained local parataxonomists worldwide, while the need for, and demands on, taxonomic services by conservation and resource management communities are rapidly increasing. Systematic collections, the material basis of biodiversity information, have been neglected and abandoned, particularly at institutions of higher learning. Considering the rapid increase in the human population and urbanization, human sustainability requires new conceptual and practical approaches to refocusing and energizing the study of the biodiversity that is the core of natural resources for sustainable development and biotic capital for sustaining our life-support system. In this paper we aim to document and extrapolate the essence of biodiversity, discuss the state and nature of taxonomic demise, the trends of recent biodiversity studies, and suggest reasonable approaches to a biodiversity science to facilitate the expansion of global biodiversity knowledge and to create useful data on backyard biodiversity worldwide towards human sustainability

    Discovery of a Modified Tetrapolar Sexual Cycle in Cryptococcus amylolentus and the Evolution of MAT in the Cryptococcus Species Complex

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    Sexual reproduction in fungi is governed by a specialized genomic region called the mating-type locus (MAT). The human fungal pathogenic and basidiomycetous yeast Cryptococcus neoformans has evolved a bipolar mating system (a, α) in which the MAT locus is unusually large (>100 kb) and encodes >20 genes including homeodomain (HD) and pheromone/receptor (P/R) genes. To understand how this unique bipolar mating system evolved, we investigated MAT in the closely related species Tsuchiyaea wingfieldii and Cryptococcus amylolentus and discovered two physically unlinked loci encoding the HD and P/R genes. Interestingly, the HD (B) locus sex-specific region is restricted (∼2 kb) and encodes two linked and divergently oriented homeodomain genes in contrast to the solo HD genes (SXI1α, SXI2a) of C. neoformans and Cryptococcus gattii. The P/R (A) locus contains the pheromone and pheromone receptor genes but has expanded considerably compared to other outgroup species (Cryptococcus heveanensis) and is linked to many of the genes also found in the MAT locus of the pathogenic Cryptococcus species. Our discovery of a heterothallic sexual cycle for C. amylolentus allowed us to establish the biological roles of the sex-determining regions. Matings between two strains of opposite mating-types (A1B1×A2B2) produced dikaryotic hyphae with fused clamp connections, basidia, and basidiospores. Genotyping progeny using markers linked and unlinked to MAT revealed that meiosis and uniparental mitochondrial inheritance occur during the sexual cycle of C. amylolentus. The sexual cycle is tetrapolar and produces fertile progeny of four mating-types (A1B1, A1B2, A2B1, and A2B2), but a high proportion of progeny are infertile, and fertility is biased towards one parental mating-type (A1B1). Our studies reveal insights into the plasticity and transitions in both mechanisms of sex determination (bipolar versus tetrapolar) and sexual reproduction (outcrossing versus inbreeding) with implications for similar evolutionary transitions and processes in fungi, plants, and animals

    The NS1 Glycoprotein Can Generate Dramatic Antibody-Enhanced Dengue Viral Replication in Normal Out-Bred Mice Resulting in Lethal Multi-Organ Disease

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    Antibody-enhanced replication (AER) of dengue type-2 virus (DENV-2) strains and production of antibody-enhanced disease (AED) was tested in out-bred mice. Polyclonal antibodies (PAbs) generated against the nonstructural-1 (NS1) glycoprotein candidate vaccine of the New Guinea-C (NG-C) or NSx strains reacted strongly and weakly with these antigens, respectively. These PAbs contained the IgG2a subclass, which cross-reacted with the virion-associated envelope (E) glycoprotein of the DENV-2 NSx strain, suggesting that they could generate its AER via all mouse Fcγ-receptor classes. Indeed, when these mice were challenged with a low dose (<0.5 LD50) of the DENV-2 NSx strain, but not the NG-C strain, they all generated dramatic and lethal DENV-2 AER/AED. These AER/AED mice developed life-threatening acute respiratory distress syndrome (ARDS), displayed by diffuse alveolar damage (DAD) resulting from i) dramatic interstitial alveolar septa-thickening with mononuclear cells, ii) some hyperplasia of alveolar type-II pneumocytes, iii) copious intra-alveolar protein secretion, iv) some hyaline membrane-covered alveolar walls, and v) DENV-2 antigen-positive alveolar macrophages. These mice also developed meningo-encephalitis, with greater than 90,000-fold DENV-2 AER titers in microglial cells located throughout their brain parenchyma, some of which formed nodules around dead neurons. Their spleens contained infiltrated megakaryocytes with DENV-2 antigen-positive red-pulp macrophages, while their livers displayed extensive necrosis, apoptosis and macro- and micro-steatosis, with DENV-2 antigen-positive Kuppfer cells and hepatocytes. Their infections were confirmed by DENV-2 isolations from their lungs, spleens and livers. These findings accord with those reported in fatal human “severe dengue” cases. This DENV-2 AER/AED was blocked by high concentrations of only the NG-C NS1 glycoprotein. These results imply a potential hazard of DENV NS1 glycoprotein-based vaccines, particularly against DENV strains that contain multiple mutations or genetic recombination within or between their DENV E and NS1 glycoprotein-encoding genes. The model provides potential for assessing DENV strain pathogenicity and anti-DENV therapies in normal mice

    Parallels, prescience and the past: analogical reasoning and contemporary international politics

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    Analogical reasoning has held a perpetual appeal to policymakers who have often drafted in historical metaphor as a mode of informing decision-making. However, this article contends that since the beginning of the ‘War on Terror’ we have arguably seen the rise of a more potent form of analogy, namely ones that are selected because they fulfil an ideological function. Analogical reasoning as a tool of rational decision-making has increasingly become replaced by analogical reasoning as a tool of trenchant ideologically-informed policy justification. This article addresses three key areas which map out the importance of analogical reasoning to an understanding of developments in contemporary international politics: the relationship between history and politics, in intellectual and policy terms; a critical assessment of the appeal that analogical reasoning holds for policymakers; and the development of a rationale for a more effective use of history in international public policymaking

    Mycobacterial PIMs Inhibit Host Inflammatory Responses through CD14-Dependent and CD14-Independent Mechanisms

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    Mycobacteria develop strategies to evade the host immune system. Among them, mycobacterial LAM or PIMs inhibit the expression of pro-inflammatory cytokines by activated macrophages. Here, using synthetic PIM analogues, we analyzed the mode of action of PIM anti-inflammatory effects. Synthetic PIM1 isomer and PIM2 mimetic potently inhibit TNF and IL-12 p40 expression induced by TLR2 or TLR4 pathways, but not by TLR9, in murine macrophages. We show inhibition of LPS binding to TLR4/MD2/CD14 expressing HEK cells by PIM1 and PIM2 analogues. More specifically, the binding of LPS to CD14 was inhibited by PIM1 and PIM2 analogues. CD14 was dispensable for PIM1 and PIM2 analogues functional inhibition of TLR2 agonists induced TNF, as shown in CD14-deficient macrophages. The use of rough-LPS, that stimulates TLR4 pathway independently of CD14, allowed to discriminate between CD14-dependent and CD14-independent anti-inflammatory effects of PIMs on LPS-induced macrophage responses. PIM1 and PIM2 analogues inhibited LPS-induced TNF release by a CD14-dependent pathway, while IL-12 p40 inhibition was CD14-independent, suggesting that PIMs have multifold inhibitory effects on the TLR4 signalling pathway

    Frequent Long-Range Epigenetic Silencing of Protocadherin Gene Clusters on Chromosome 5q31 in Wilms' Tumor

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    Wilms' tumour (WT) is a pediatric tumor of the kidney that arises via failure of the fetal developmental program. The absence of identifiable mutations in the majority of WTs suggests the frequent involvement of epigenetic aberrations in WT. We therefore conducted a genome-wide analysis of promoter hypermethylation in WTs and identified hypermethylation at chromosome 5q31 spanning 800 kilobases (kb) and more than 50 genes. The methylated genes all belong to α-, β-, and γ-protocadherin (PCDH) gene clusters (Human Genome Organization nomenclature PCDHA@, PCDHB@, and PCDHG@, respectively). This demonstrates that long-range epigenetic silencing (LRES) occurs in developmental tumors as well as in adult tumors. Bisulfite polymerase chain reaction analysis showed that PCDH hypermethylation is a frequent event found in all Wilms' tumor subtypes. Hypermethylation is concordant with reduced PCDH expression in tumors. WT precursor lesions showed no PCDH hypermethylation, suggesting that de novo PCDH hypermethylation occurs during malignant progression. Discrete boundaries of the PCDH domain are delimited by abrupt changes in histone modifications; unmethylated genes flanking the LRES are associated with permissive marks which are absent from methylated genes within the domain. Silenced genes are marked with non-permissive histone 3 lysine 9 dimethylation. Expression analysis of embryonic murine kidney and differentiating rat metanephric mesenchymal cells demonstrates that Pcdh expression is developmentally regulated and that Pcdhg@ genes are expressed in blastemal cells. Importantly, we show that PCDHs negatively regulate canonical Wnt signalling, as short-interfering RNA–induced reduction of PCDHG@ encoded proteins leads to elevated β-catenin protein, increased β-catenin/T-cell factor (TCF) reporter activity, and induction of Wnt target genes. Conversely, over-expression of PCDHs suppresses β-catenin/TCF-reporter activity and also inhibits colony formation and growth of cancer cells in soft agar. Thus PCDHs are candidate tumor suppressors that modulate regulatory pathways critical in development and disease, such as canonical Wnt signaling

    Payments and quality of care in private for-profit and public hospitals in Greece

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    <p>Abstract</p> <p>Background</p> <p>Empirical evidence on how ownership type affects the quality and cost of medical care is growing, and debate on these topics is ongoing. Despite the fact that the private sector is a major provider of hospital services in Greece, little comparative information on private versus public sector hospitals is available. The aim of the present study was to describe and compare the operation and performance of private for-profit (PFP) and public hospitals in Greece, focusing on differences in nurse staffing rates, average lengths of stay (ALoS), and Social Health Insurance (SHI) payments for hospital care per patient discharged.</p> <p>Methods</p> <p>Five different datasets were prepared and analyzed, two of which were derived from information provided by the National Statistical Service (NSS) of Greece and the other three from data held by the three largest SHI schemes in the country. All data referred to the 3-year period from 2001 to 2003.</p> <p>Results</p> <p>PFP hospitals in Greece are smaller than public hospitals, with lower patient occupancy, and have lower staffing rates of all types of nurses and highly qualified nurses compared with public hospitals. Calculation of ALoS using NSS data yielded mixed results, whereas calculations of ALoS and SHI payments using SHI data gave results clearly favoring the public hospital sector in terms of cost-efficiency; in all years examined, over all specialties and all SHI schemes included in our study, unweighted ALoS and SHI payments for hospital care per discharge were higher for PFP facilities.</p> <p>Conclusions</p> <p>In a mixed healthcare system, such as that in Greece, significant performance differences were observed between PFP and public hospitals. Close monitoring of healthcare provision by hospital ownership type will be essential to permit evidence-based decisions on the future of the public/private mix in terms of healthcare provision.</p
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