113 research outputs found

    Geographical analysis of forest types based on a digital elevation model generated from synthetic aperture radar

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    This research aims to examine forest type distribution, based on slope and aspect maps, generated from synthetic aperture radar (SAR) data. The study is conducted over an area about 1564.9 km2 located in Khutag-Undur soum of Bulgan aimag (province), northern Mongolia. Sentinel-1 interferometric SAR images acquired on 5 and 17 October of 2020 are used to generate a digital elevation model (DEM). For a forest type classification, geocoded Sentinel-2 multispectral images acquired on 5 July and 27 September of 2019 are used. Initially, a DEM creation from the SAR data is performed and the slope and aspect maps are generated, following which geographical analysis is performed using slope, aspect and classified forest type maps. The result of the analysis shows that about half of the forested areas face the north-west, north and north-east directions. It also revealed that evergreen conifers are distributed on slopes of moderate degrees facing towards the south-east and south, whereas the deciduous conifers are mainly distributed on relatively steep slopes facing south-west, west and north-west

    Fusion of Multisource Images for Update of Urban GIS

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    Co-recognition of β-glucan and chitin and programming of adaptive immunity to Aspergillus fumigatus

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    The prevalence of fungal infections has increased concurrently with increases in immune suppressive therapies and susceptible individuals. Opportunistic fungal pathogens such as Aspergillus fumigatus may exhibit invasive growth and dissemination resulting in a high mortality rate. Herein, we discuss how immune sensing of germination directs innate immune responses and programs adaptive responses that could promote or impair immune protection during periods of heightened susceptibility. In infected individuals, Th1 responses are the most protective, while Th2 responses lead to poor disease outcomes. In particular, the roles of β-glucan and chitin co-recognition in shaping Th1- and Th2-type immunity to fungal infection are explored. We discuss how fungal responses to environmental stresses could result in decreased immune protection from infection, particularly in response to anti-fungal drugs that target β-glucan synthesis. Furthermore, we consider how experimental modulation of host-pathogen interactions might elucidate the mechanisms of protective and detrimental immunity and the potential of current and future studies to promote the development of improved treatments for patients that respond poorly to existing therapies

    Lung eosinophil recruitment in response to Aspergillus fumigatus is correlated with fungal cell wall composition and requires γδ T cells

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    The differential recognition of fungal cell wall polysaccharides that program innate and adaptive immunity to the human opportunistic fungal pathogen Aspergillus fumigatus has been a focus of considerable interest. In a mouse model of fungal conidia aspiration, decreased relative levels of cell wall core carbohydrates β-1,3-glucan to chitin in A. fumigatus isolates and mutant strains were correlated with increased airway eosinophil recruitment. In addition, an increase in fungal surface chitin exposure induced by the β-1,3-glucan synthesis-targeting drug caspofungin was associated with increased murine airway eosinophil recruitment after a single challenge of conidia. The response to increased A. fumigatus chitin was associated with increased transcription of IL-17A after a single aspiration, although this cytokine was not required for eosinophil recruitment. Rather, both RAG1 and γδ T cells were required, suggesting that this subset of innate-like lymphocytes may be an important regulator of potentially detrimental type 2 immune responses to fungal inhalation and infection

    Reciprocal Inhibition of Adiponectin and Innate Lung Immune Responses to Chitin and Aspergillus fumigatus

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    Chitin is a structural biopolymer found in numerous organisms, including pathogenic fungi, and recognized as an immune-stimulating pathogen associated molecular pattern by pattern recognition molecules of the host immune system. However, programming and regulation of lung innate immunity to chitin inhalation in the context of inhalation of fungal pathogens such as Aspergillus fumigatus is complex and our understanding incomplete. Here we report that the systemic metabolism-regulating cytokine adiponectin is decreased in the lungs and serum of mice after chitin inhalation, with a concomitant decrease in surface expression of the adiponectin receptor AdipoR1 on lung leukocytes. Constitutive lung expression of acidic mammalian chitinase resulted in decreased inflammatory cytokine gene expression and neutrophil recruitment, but did not significantly affect lung adiponectin transcription. Exogenous recombinant adiponectin specifically dampened airway chitin-mediated eosinophil recruitment, while adiponectin deficiency resulted in increased airway eosinophils. The presence of adiponectin also resulted in decreased CCL11-mediated migration of bone marrow-derived eosinophils. In contrast to purified chitin, aspiration of viable conidia from the high chitin-expressing A. fumigatus isolate Af5517 resulted in increased neutrophil recruitment and inflammatory cytokine gene expression in adiponectin-deficient mice, while no significant changes were observed in response to the isolate Af293. Our results identify a novel role for the adiponectin pathway in inhibition of lung inflammatory responses to chitin and A. fumigatus inhalation

    Forest fire risk assessment model using Remote sensing and GIS techniques in Tujiin nars national park, Mongolia

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    Forest is an important natural resource that should be carefully protected and rationally managed. In recent years, deforestation and forest land degradation have become the main concern for forest specialists as well as policy and decision-makers dealing with environment issues. It has been found that much of the existing forests have been destroyed, mainly by shifting cultivation, timber preparation, legal and illegal logging, and forest fires. To protect and conserve the deteriorating forest, it is very important to conduct forest-related risk assessment and map the outcomes in a spatial domain. The aim of this research is to conduct a forest fire risk assessment mapping of Tujiin Nars National Park using geographic information system (GIS) and remote sensing (RS) techniques. The research approach is based on an empirical model. It includes three parameters (i.e. geomorphology, vegetation cover combustibility and human activity) that are crucial for the forest fire assessment. The results of the study can be used for different decision making processes

    Histological Quantification to Determine Lung Fungal Burden in Experimental Aspergillosis

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    The quantification of lung fungal burden is critical for the determination of the relative levels of immune protection and fungal virulence in mouse models of pulmonary fungal infection. Although multiple methods are used to assess fungal burden, quantitative polymerase chain reaction (qPCR) of fungal DNA has emerged as a technique with several advantages over previous culture-based methods. Currently, a comprehensive assessment of lung pathology, leukocyte recruitment, fungal burden, and gene expression in mice with invasive aspergillosis (IA) necessitates the use of a significant number of experimental and control animals. Here the quantification of lung histological staining to determine fungal burden using a reduced number of animals was examined in detail. Lung sections were stained to identify fungal structures with Gomori's modified methanamine silver (GMS) staining. Images were taken from the GMS-stained sections from 4 discrete fields of each formalin-fixed paraffin-embedded lung. The GMS stained areas within each image were quantified using an image analysis program, and from this quantification, the mean percentage of stained area was determined for each sample. Using this strategy, eosinophil-deficient mice exhibited decreased fungal burden and disease with caspofungin therapy, while wild-type mice with IA did not improve with caspofungin. Similarly, fungal burden in mice lacking γδ T cells were also improved by caspofungin, as measured by qPCR and GMS quantification. GMS quantification is therefore introduced as a method for the determination of relative lung fungal burden that may ultimately reduce the quantity of experimental animals required for comprehensive studies of invasive aspergillosi

    Caspofungin Increases Fungal Chitin and Eosinophil and γδ T Cell-Dependent Pathology in Invasive Aspergillosis

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    The polysaccharide-rich fungal cell wall provides pathogen-specific targets for antifungal therapy and distinct molecular patterns that stimulate protective or detrimental host immunity. The echinocandin antifungal caspofungin inhibits synthesis of cell wall β-1,3-glucan and is used for prophylactic therapy in immune-suppressed individuals. However, breakthrough infections with fungal pathogen Aspergillus fumigatus are associated with caspofungin prophylaxis. In this study, we report in vitro and in vivo increases in fungal surface chitin in A. fumigatus induced by caspofungin that was associated with airway eosinophil recruitment in neutropenic mice with invasive pulmonary aspergillosis (IA). More importantly, caspofungin treatment of mice with IA resulted in a pattern of increased fungal burden and severity of disease that was reversed in eosinophil-deficient mice. Additionally, the eosinophil granule proteins major basic protein and eosinophil peroxidase were more frequently detected in the bronchoalveolar lavage fluid of lung transplant patients diagnosed with IA that received caspofungin therapy when compared with azole-treated patients. Eosinophil recruitment and inhibition of fungal clearance in caspofungin-treated mice with IA required RAG1 expression and γδ T cells. These results identify an eosinophil-mediated mechanism for paradoxical caspofungin activity and support the future investigation of the potential of eosinophil or fungal chitin-targeted inhibition in the treatment of IA
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