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Burc, Laurence. "Suivi épidémiologique des "Aspergillus" pathogènes dans les services d'hématologie et de réanimation pneumologique à l'hôpital Beaujon : typage moléculaire de souches d'"Aspergillus fumigatus" isolées de patients et de leur proche environnement." Paris 5, 1997. http://www.theses.fr/1997PA05P098.
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Bertout, Sébastien. "Polymophisme génétique de souche d'Aspergillus fumigatus isolées d'aspergilloses pulmonaires au cours d'une étude multicentrique." Montpellier 1, 2000. http://www.theses.fr/2000MON13512.
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Philippe, Bruno. "Aspergillose pulmonaire invasive : interactions entre Aspergillus fumigatus et macrophage alvéolaire." Paris 12, 2004. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990003948260204611&vid=upec.
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L'aspergillose pulmonaire invasive (AI) due à Aspergillus fumigatus est une infection grave du malade immunodéprimé. Un modèle murin d'AI a montré que le macrophage alvéolaire (MA) représente la première ligne des défenses pulmonaires innées contre A. Fumigatus. Le killing est lent et fait intervenir les réactifs oxydants. Les corticostéroi͏̈des diminuent les capacités de killing en inhibant la production de réactifs oxydants par les MA. L'analyse du killing de A. Fumigatus par des MA de malades transplantés pulmonaires a montré des résultats similaires aux MA murins. La dose de corticostéroi͏̈des prise quotidiennenement > 0,25 mg/kg/j, la dose totale > 1,5 mg/kg/j et la période précoce < 6 mois après la transplantation ont été retrouvés comme facteurs diminuant le niveau de killing des conidies par les MA. Ces résultats démontrent le rôle essentiel du MA dans la résistance de l'homme à A. FumigatusPulmonary invasive aspergillosis (lA) due to Aspergllus fumigatus is a severe infection in immunocompromised patients. A murine model of invasive aspergillosis showed that alveolar macrophages (AM) are the first une of pulmonary innate defence against A. Fumigatus. The killing is slow and involves reactive oxidants intermediates. Corticosteroids decrease killing capacity of the AM du to an inhibition of reactive oxidants intermediates production. Killing study of lung transplant recipients showed similar resuits as murin AM. Several factors that influence the killing were identified daily dose of corticosteroids > 0,25 g/kg/d total dose> 1,5 mg/kg/d and early period post transplantation <6 months were found to decrease significatively the killing rate. These data demonstrated unequivocally that the alveolar macrophage is the first une of defence against A. Fumigatus
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Philippe, Bruno Latgé Jean-Paul. "Aspergillose pulmonaire invasive interactions entre Aspergillus fumigatus et macrophage alvéolaire /." Créteil : Université de Paris-Val-de-Marne, 2007. http://doxa.scd.univ-paris12.fr:8080/theses-npd/th0394826.htm.
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Thèse de doctorat : Sciences de la vie et de la santé : Paris 12 : 2004.Version électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Titre provenant de l'écran-titre. Bibliogr. : 305 réf.
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Leleu, Christopher. "Evaluation du risque lié à l'exposition aérienne à Aspergillus fumigatus." Paris 6, 2012. http://www.theses.fr/2012PA066413.
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Aspergillus fumigatus est un champignon filamenteux pathogène responsable de différentes formes d’infections pulmonaires allergiques sur les sujets immunocompétents et d’infections invasives chez les patients neutropéniques. L’inhalation de spores est le mode habituel de contamination suggérant un rôle majeur de l’environnement dans l’épidémiologie de l’aspergillose. Cependant, la relation entre les concentrations d’Aspergillus dans l’air et la probabilité d’infections ne sont pas connues. Dans cette étude, trois approches complémentaires ont été proposées pour analyser cette relation. In vitro, nous avons utilisé un dispositif de culture en interface air-liquide pour analyser les conséquences de l’exposition de cellules pulmonaires A549 à différentes concentrations de spores d’Aspergillus fumigatus. Aucun effet significatif sur la production de cytokines pro-inflammatoires n'a été retrouvé suite à cette exposition, même lorsque cette exposition aspergillaire était combinée avec une exposition au formaldéhyde. In vivo, la relation entre l’exposition à des spores d’Aspergillus et la survenue d’une infection a été étudiée dans un modèle murin d’aspergillose invasive en utilisant la souche de référence Af293 d’Aspergillus fumigatus. Dans une approche bayésienne la relation dose-infection entre probabilité d’infection et exposition aux spores a été estimée en utilisant le modèle exponentiel et le modèle plus flexible bêta-Poisson. Ceci a permis d’estimer la dose infectieuse 50 à 1,8-1,9. 104 spores inhalées viables. Secondairement, ce modèle a été utilisé pour mettre au point un nouveau modèle de réactivation d’aspergillose et étudier l’efficacité de l’amphotéricine B liposomale dans la prophylaxie de l’aspergillose invasive. Chez l’homme, nous avons tenté d’estimer la relation entre l’exposition environnementale aux spores fongiques et l’incidence de la colonisation ou de l’infection aspergillaire chez 44 transplantés pulmonaires étudiée de façon consécutive. A l'aide d'un modèle de régression par GEE, nous avons trouvé une relation significative entre la contamination des surfaces par Aspergillus et l’incidence de la colonisation. De plus, nous avons montré des identités génotypiques entre les isolats cliniques et environnementaux d’Aspergillus, ce qui confirme les risques d’acquisition d’Aspergillus dans le cadre hospitalier. Globalement, ces résultats apportent des données nouvelles sur la relation entre la contamination environnementale et la probabilité d’aspergillose chez les patients immunodéprimésAspergillus fumigatus is an opportunistic fungal pathogen responsible for various respiratory diseases in normal hosts and severe invasive infections in neutropenic patients. Spore inhalation is the usual route of Aspergillus infection, suggesting a determining role of environmental contamination in the epidemiology of aspergillosis. However the relationship between Aspergillus concentration in the air and probability of infection is not quantitatively known. In this study, three different approaches were proposed to analyse this relationship. In vitro we used an air-liquid interface module to expose pulmonary A549 cells to high concentrations of A. Fumigatus spores, but found not effect of exposure on the production of pro-inflammatory cytokines, even when exposure was combined with exposure to formaldehyde. In vivo, the relationship between spore exposure and infection was examined in a murine model of invasive aspergillosis, using the reference Af293 strain of A. Fumigatus. In a bayesian approach, the dose-response relationship between the probability of infection and spore exposure was approximated using the exponential model and the more flexible beta-Poisson model. It allowed estimating the median infective dose at 1. 8-1. 9x104 inhaled viable spores. Further, this model was used to develop a unique model of reactivating aspergillosis and then to examine the efficacy of liposomal amphotericin B on prophylaxis of aspergillosis. In human, we attempted to estimate the relationship between environmental exposure to fungal spores and the incidence of Aspergillus colonization or infection in 44 consecutive lung transplant recipients. In a GEE multivariate analysis, we found a significant relationship between surface contamination by Aspergillus and the incidence of colonization. Furthermore, we found genotypic similarities between clinical and environmental isolates of Aspergillus, which confirm the risk of acquisition of Aspergillus in the hospital setting. Altogether, this result provides new insights into the relationship between airborne exposure and probability of aspergillosis in immunocompromised hosts
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Ohlen, Ingrid. "Analyse du caractère nosocomial de deux cas d'aspergillose invasive à A. Flavus par typage moléculaire R. A. P. D. (Random Amplification Polymorphic DNA)." Paris 5, 1999. http://www.theses.fr/1999PA05P006.
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Chauvin, David. "Nouvelles stratégies de traitement de l'aspergillose : ciblage d'Aspergillus fumigatus par des anticorps thérapeutiques et ciblage du microenvironnement fongique." Thesis, Tours, 2018. http://www.theses.fr/2018TOUR3310.
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Due au champignon Aspergillus fumigatus, l’aspergillose pulmonaire invasive représente une grave menace pour les individus souffrant d’immunodépression sévère. En parallèle d’un diagnostic manquant de spécificité, les traitements actuels présentent une forte toxicité. Ces travaux se sont dans un premier temps intéressés au développement d’anticorps thérapeutiques dirigés contre les protéines pariétales Chitin ring formation du champignon. Le ciblage de ces protéines impliquées dans la croissance fongique a permis la mise en évidence d’effets modérés in vitro, et ont induit, in vivo, un recrutement significatif de cellules immunitaires impliquées dans la défense anti-aspergillaire. Dans un second temps, ces travaux se sont intéressés au ciblage du microenvironnement et de la réponse de l’hôte au cours de l’aspergillose, afin de mieux comprendre les processus physiopathologiques induits au cours de la maladie, et de permettre l’identification de nouveaux biomarqueurs et cibles thérapeutiques. L’utilisation de la spectrométrie de masse iTRAQ®, chez des rats et des manchots, a permis la mise en évidence de plusieurs voies de signalisation surreprésentées. Ces travaux se sont également intéressés à la caractérisation immunologique d’un modèle rat d’API. En plus de la mise en évidence des effets du champignon sur le recrutement de certaines populations de cellules immunitaires, l’utilisation de l’iTRAQ® a permis la mise en évidence de la surexpression de l’interleukine-33 et de son récepteur ST2 au cours de la maladie. Ces travaux ouvrent d’intéressantes perspectives dans la mise en place de nouveaux traitements contre l’APICaused by the fungus Aspergillus fumigatus, invasive pulmonary aspergillosis is a serious threat for individuals suffering from severe immunosuppression. In parallel of a diagnosis lacking specificity, current treatments present a high toxicity. This work first focused on the development of therapeutic antibodies directed against cell wall proteins Chitin ring formation of the fungus. Targeting of these proteins involved in fungal growth highlighted moderate effects in vitro, and induced, in vivo, a significant recruitment of immune cells involved in anti-aspergillary defense. In a second time, this work focused on targeting the microenvironment and the host response during aspergillosis, in order to better understand pathophysiological processes induced during the disease, and allow the identification of new biomarkers and therapeutic targets. Use of iTRAQ® mass spectrometry in rat and penguins allowed the identification of several overrepresented signaling pathways. This work also focused on the immune characterization of a rat model of IPA. In addition of highlighting the effects of the fungus in the recruitment of some immune cell populations, use of iTRAQ® exhibited an overexpression of interleukin-33 and its receptor ST2 during the disease. Overall, this work is bringing interesting insights in the establishment of new treatments against IPA
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Lorösch, Stefanie. "Evaluierung des Sandwich-Enzym-Immunassays Platelia Aspergillus zur Aspergillose-Diagnostik bei Psittaziden." [S.l.] : [s.n.], 2007. http://edoc.ub.uni-muenchen.de/archive/00007436.
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Dumont, Catherine. "Sérologie de l'aspergillose : étude comparative de trois techniques de dépistage." Paris 5, 1998. http://www.theses.fr/1998PA05P148.
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Khoufache, Khaled. "Aspects toxicologiques d'Aspergillus fumigatus sur l'épithélium repiratoire in vitro." Paris 12, 2006. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990002459590204611&vid=upec.
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Le rôle des mycotoxines d'Aspergillus fumigatus sur l'épithélium respiratoire a été peu étudié. Pour étudier ces interactions, nous avons utilisé deux modèles de culture primaire de cellules épithéliales en interface air liquide l'un humain (CENH ou cellules épithéliales nasales humaines), l'autre porcin (CETP ou cellules épithéliales de trachée de porc). Afin d'identifier les mycotoxines d'A. Fumigatus impliquées dans ces interactions, nous avons travaillé à la fois sur la phase organique et sur la phase aqueuse d'un filtrat de culture d'A. Fumigatus. La phase organique des filtrat de culture mimait les effets des filtrats de culture totaux déjà décrits sur les CENH. Parmi les molécules candidates de cette phase organique, seul le verruculogène reproduisait les mêmes effets sur les paramètres électrophysiologiques. Le verruculogène est produit par toutes les souches d'A. Fumigatus et associé aux conidies. De la même manière que pour la phase organique, l'activité de la phase aqueuse a été étudiée. Les résultats semblent montrer un effet électrophysiologique marqué sur les CENH, mais aucune molécule candidate n'a, pour l'instant, été identifiée comme responsable de ces effets. Dans la 2ème partie de notre travail, une mise au point d'un modèle de CETP était effectuée. Ce modèle, de façon identique au modèle CENH, était bien différencié et composé uniquement de cellules épithéliales. L'étude des interactions antre CETP - filtrat de culture d'A. Fumigatus, verruculogène et conidies d'A. Fumigatus a montré des résultats similaires à ceux obtenus avec le modèle humain. Une immortalisation des CETP était obtenue à partir du 22ème passage. Les cellules conservaient leur aspect épithélial, mais perdaient leur différenciation mucociliaire. Le verruculogène, métabolite secondaire d'A. Fumigatus, a été pour la 1ère fois mis en évidence dans la modification des paramètres électrophysiologiques des CENH. L'activité du verruculogène pourrait être immédiate sur l'épithélium respiratoire, intervenir dans la modification de l'activité anti-microbienne du fluide de la surface apicale des cellules. Cette activité pourrait s'exercer via les canaux K+ et Na+ des CENH. Par ailleurs, le développement d'un modèle de CETP permet de dispose d'un grand potentiel de cellules afin de travailler sur de nombreux domaines impliquant A. Fumigatus et cellules des voies aériennes supérieures (phagocytose du champignon, étude de la réponse inflammatoire face à l'agression fongique, étude d'autres mycotoxines,. . . )The role of Aspergillus fumigatus mycotoxins on the respiratory epithelium has been poorly studied. To study these interactions, we have used two models of primary culture of epithelial cells in interface air liquid : one model of human nasal epithelial cells (CENH), and one model of pig tracheal epithelial cells pig (CETP). To identify the Aspergillus fumigatus mycotoxins implicated in these interactions, we worked on the organic phase and the aqueous phase of A. Fumigatus culture filtrate. The organic phase of the culture filtrates showed similar effects than totals filtrates of culture, already described on the CENH. Among the molecules candidates of this organic phase, only the verruculogen reproduced the same effects on the electrophysiological parameters. The verruculogen is produced by all the strains of A. Fumigatus and is associated to the conidia. Same manner as for the organic phase, the activity of the aqueous phase was studied. The results seem to show an electrophysiological effect marked on the CENH, but no molecule candidate, for the moment, has been identified. In the 2nd part of our work, a development of a model of CETP was carried out. This model, in a way identical to model CENH, well was differentiated and composed only of epithelial cells. The study of the interactions between CETP - culture filtrates of A. Fumigatus, verruculogen and A. Fumigatus conidia’s showed similar results with those obtained with the human model. An immortalization of the CETP has been obtained starting from the 22nd passage. The cells preserved their epithelial aspect, but lost their mucociliary differentiation. The verruculogen, secondary metabolite of A. Fumigatus, was for the 1st time highlighted in the modification of the electrophysiological parameters of the CENH. The activity of verruculogen could be immediate on the respiratory epithelium, to interfere in the modification of the antimicrobial activity of apical surface fluid of the cells. This activity could be exerted via the K+ and Na+ channels of the CENH. In addition, the development of a model of CETP makes it possible to have a great potential of cells in order to work on many fields implying A. Fumigatus and cells of the higher air routes (phagocytosis of fungi, study of the inflammatory response against the fungus aggression, study of other mycotoxins. . . )
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Bart-Delabesse, Emmanuelle. "Développement d'un système de typage d'Aspergillus fumigatus au moyen de microsatellites polymorphe : implications écologiques et épidémiologiques." Paris 12, 1999. http://www.theses.fr/1999PA120046.
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L'aspergillose invasive (ai) due a aspergillus fumigatus est devenue une cause majeure de deces chez les patients immunodeprimes. La pathogenese et l'epidemiologie de cette mycose opportuniste sont mal connues, ce qui rend sa prevention particulierement difficile. Devant le manque de fiabilite et/ou de rapidite des methodes de typage actuelles, un systeme de differenciation infraspecifique d'aspergillus fumigatus a ete developpe, au moyen de microsatellites. Le polymorphisme de 4 sequences riches en (ca), issues d'une banque genomique criblee avec un oligonucleotide (ca) 1 0, a ete evalue par pcr en determinant la taille des alleles sur un sequenceur automatique. L'analyse de 50 isolats environnementaux, 50 isolats de patients et de deux souches de reference a permis de detecter respectivement 12, 11, 10 et 23 alleles aux 4 loci (pouvoir discriminant = 0,994). Les resultats, hautement reproductibles, peuvent etre obtenus directement a partir de conidies. Aucun regroupement n'a ete observe selon l'origine clinique ou environnementale des isolats, suggerant que tout isolat est potentiellement pathogene. Afin d'etablir l'origine nosocomiale de l'ai, les isolats, recueillis sur 12 mois, de patients souffrant de maladies hematologiques et d'ai a l'hopital h-mondor (27 isolats, 12 patients) et de leur environnement (62 isolats), ont ete types. Une origine nosocomiale a ete trouvee pour 42% des patients. La grande biodiversite revelee au sein de la population environnementale (51 genotypes), la possibilite qu'un genotype persiste au cours du temps (8 genotypes), et l'absence de methodes exhaustives de prelevements constituent les facteurs limitants pour prouver la nosocomialite et reclame une meilleure connaissance des populations environnementales d'a. Fumigatus. Dans cette perspective, le typage par microsatellites apparait comme un systeme plus approprie que le typage par rapd, de par sa fiabilite, ou que le typage par rflp, de par sa rapidite et sa perfectibilite.
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Khoufache, Khaled Bretagne Stéphane. "Aspects toxicologiques d'Aspergillus fumigatus sur l'épithélium repiratoire in vitro." Créteil : Université de Paris-Val-de-Marne, 2006. http://doxa.scd.univ-paris12.fr:80/theses/th0245959.pdf.
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Loeffert, Sophie. "Prévention, contrôle et maîtrise du risque d’aspergillose invasive au Groupement Hospitalier Edouard Herriot lors de travaux : apport de la surveillance et de l’alerte environnementale et épidémiologique." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1246/document.
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Lors de travaux, la mise en suspension des spores d’Aspergillus constitue un facteur de risque reconnu dans le développement d’une aspergillose invasive. Durant l’année 2015, un pavillon de 6000 m2 (60 lits) de notre établissement a été entièrement déconstruit. L’objectif principal de cette étude a été d’évaluer l’association entre la concentration des spores d’Aspergillus fumigatus (AF) dans l’environnement extérieur et intérieur des pavillons, mais également avec la coexistence de cas cliniques, afin de proposer des recommandations d’amélioration (pratiques & techniques). Pour cela, durant 11 mois, une surveillance prospective de la contamination à Aspergillus fumigatus (AF) de l’air extérieur et intérieur par impaction sur gélose, mais aussi une investigation épidémiologique des patients à risque ont été mis en place. Au total, 3885 prélèvements d’air ont été réalisés (1744 extérieurs et 2141 intérieurs) permettant, par calcul des ratios de contamination (extérieurs vs intérieurs), de confirmer une efficacité des mesures de précautions pour réduire l’aérocontamination. Des prélèvements extérieurs continus des spores d’Aspergillacées (spore/m3/jour) ont également été réalisés par un capteur Hirst. Ce capteur, mais aussi le suivi des conditions météorologiques se sont révélés être des systèmes d’alerte utiles pour prévenir les pics de contamination. Enfin, 394 (383 environnementaux, 11 cliniques) isolats d’AF sensibles aux antifongiques ont été génotypés (MLVA). L’analyse des génotypes a montré 7 génotypes similaires entre des isolats d’AF cliniques et environnementaux confirmant un rôle de l’environnement hospitalier dans l’infection ou la colonisation des patientsInvasive aspergillosis (IA) due to Aspergillus has been associated with building construction, which may increase spores emission nearby immunocompromised patients. In 2015, one blocks of 6,000 m2 (60 beds) form our hospital has been entirely demolished. The aim of this study was to evaluate possible association between concentration of A. fumigatus (AF) spores in the outdoor and indoor environment and also with the clinical cases in order to propose some improvements in actuals methods and practices. A daily surveillance of fungal contamination was implemented during 11-months. Environmental survey was realized by air samplings, outdoor and indoor, with an automatic agar sampler. In parallel, surveillance of IA infection cases was conducted by epidemiological investigation. A total of 3885 air samples (1744 outdoor samples and 2141 indoor samples) were collected, allowing calculation of ratios (outdoor vs indoor) to confirm efficacy of preventives measures applied to reduce indoor aerocontamination. Outdoor continuous sampling of Aspergillaceae spores (spore/m3/day) was also realized by a Hirst collector. This collector was useful as alarm system to detect contamination peaks. Similarly, monitoring of meteorological parameters seems to be an interesting tool, to prevent Aspergillus peaks. Finally, 394 isolates of AF, susceptible to antifungals (383 environmental and 11 clinical isolates) were genotyped using MLVA. Analysis of genotypes showed 7 similar genotypes shared by environmental and clinical isolates, suggesting that clinical colonization and/or infection may originate from the hospital environment
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Lorösch, Stefanie. "Evaluierung des Sandwich-Enzym-Immunassays Platelia® Aspergillus zur Aspergillose-Diagnostik bei Psittaziden." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-74360.
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Howard, Susan J. "Azole Resistance in Aspergillus." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503743.
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Watson, A. J. "Aflatoxin biosynthesis in Aspergillus." Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267259.
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Johnstone, Iain Lindsay. "Transformation of Aspergillus nidulans." Thesis, University of Glasgow, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313341.
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Caddick, M. X. "Phosphatases of Aspergillus nidulans." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372304.
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Tilburn, J. "Transformation of Aspergillus nidulans." Thesis, University of Essex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234198.
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Frandon, Isabelle. "Actions physiologique et moléculaire de glucocorticoïdes sur Aspergillus fumigatus." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE18006.
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Piarroux, Raphaël. "Développement de tests de diagnostic in vitro appliqués au sérodiagnostic des infections fongiques par western blot et immunochromatographie." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0763/document.
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Le champignon microscopique Aspergillus fumigatus provoque un nombre important de maladies graves. Parmi elles, l’aspergillose pulmonaire chronique (APC) et l’aspergillose broncho-pulmonaire allergique (ABPA) affectent 3 et 4,8 millions de personnes dans le monde, respectivement.L’APC est très souvent mortelle si elle n’est pas soignée. Elle se développe très souvent après une tuberculose. C’est donc une maladie des pays émergents, où il n’est souvent pas possible de la diagnostiquer à cause du coût trop important des techniques existantes.L’ABPA est une complication très grave de l’asthme et de la mucoviscidose, qui complique fortement ces maladies. Elle est très difficile à diagnostiquer.Notre travail a donc consisté à développer et évaluer deux tests, un test rapide permettant de poser le diagnostic d’APC sans avoir à utiliser de matériel de laboratoire à destination des pays émergents et un western blot qui permet la confirmation du diagnostic d’ABPAAspergillus fumigatus is a microscopic fungus that can cause numerous diseases. Among them, chronic pulmonary aspergillosis (CPA) and allergic broncho-pulmonary aspergilloses (ABPA) affect 3 and 4.8 million people, respectively.CPA is often fatal if left untreated. It is often a complication of tuberculosis and therefore affect low and middle income countries. However, it is difficult to diagnose it in those countries, as the tests are too expansive.ABPA is a severe complication of asthma and cystic fibrosis, worsening those diseases. It’s very hard to diagnose it.Our work was to develop and evaluate two tests, a rapid test for the diagnosis of CPA that does not require laboratory equipment designed for low and middle income countries and a western blot for confirmation of ABPA diagnosis
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Durand-Perdriel, François. "Aspergillose broncho-pulmonaire allergique (ABPA) (ou maladie de Hinson-Pepys) : à propos de six nouvelles observations dans l'Ouest." Nantes, 1985. http://www.theses.fr/1985NANT3351.
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Hamet, Nicole. "Contribution à la prophylaxie de l'aspergillose des volailles." Université Joseph Fourier (Grenoble), 1990. http://www.theses.fr/1990GRE18005.
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Madeira, Jovita Eugenia Gazzinelli Cruz. "DNA polymorphisms in toxigenic and nontoxigenic isolates of Aspergillus flavus and Aspergillus parasiticus." Thesis, King's College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267939.
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Calderari, Thaiane Ortolan 1986. "Biodiversidade de fungos aflatoxigênicos e aflatoxinas em castanha do Brasil." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254596.
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Orientadores: José Luiz Pereira, Marta Hiromi TaniwakiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A castanha do Brasil (Bertholletia excelsa) é uma das mais importantes espécies de exploração extrativista da floresta Amazônica, sendo exportada para diversos países devido ao seu alto valor nutritivo. No entanto, os baixos níveis tecnológicos característicos de sua cadeia produtiva, considerada ainda extrativista e as condições inadequadas de manejo da matéria prima, favorecem o aparecimento de contaminação por fungos produtores de aflatoxinas, compostos tóxicos considerados cancerígenos para humanos. Este problema é um entrave para a comercialização do produto, principalmente no mercado externo, dado ao rigoroso controle de países europeus e Estados Unidos em relação aos níveis de toxinas presentes nos alimentos. Nestas condições, o presente trabalho teve por objetivo investigar a incidência de fungos em castanhas do Brasil e avaliar o potencial toxigênico dos isolados Aspergillus section flavi para a produção de aflatoxinas, bem como analisar a presença de aflatoxinas nesta matriz. Um total de 143 amostras provenientes dos Estados do Pará, Amazonas e São Paulo em diferentes etapas da cadeia produtiva da castanha foi analisado. A técnica utilizada para análise da infecção fúngica foi o plaqueamento direto em meio Dicloran 18% Glicerol. Os resultados foram expressos em porcentagem de infecção fúngica. Os isolados suspeitos foram purificados em meio Czapek extrato de levedura ágar e incubados a 25ºC/7 dias em diferentes temperaturas para a identificação das espécies. Para a análise do potencial toxigênico de cada isolado da seção flavi foi utilizada a técnica do ágar plug. Para a análise de aflatoxinas foi utilizada coluna de imunoafinidade para extração e limpeza das amostras e Cromatografia Líquida de Alta Eficiência e detector de fluorescência acoplado ao sistema de derivatização Kobracell para detecção e quantificação das aflatoxinas. Dentre o total de amostras coletadas, aquelas provenientes das florestas foram as que apresentaram maior valor médio de atividade de água, assim como maior porcentagem de infecção fúngica quantificada e biodiversidade de espécies. Considerando todas as amostras avaliadas, foram no total 13.421 isolados de fungos filamentosos, sendo que as espécies mais incidentes foram Aspergillus flavus, Aspergillus nomius, Penicillium citrinum, Aspergillus tamarii, Syncephalastrum racemosum e Penicillium sp. Dentre as espécies encontradas, 450 isolados de Aspergillus nomius e 9 de Aspergillus parasiticus foram identificados e 100% apresentaram capacidade de produção de aflatoxinas AFB1, AFB2, AFG1, AFG2. Dos de 703 isolados de Aspergillus flavus, 63,5% apresentaram a capacidade de produzir aflatoxinas AFB1 e AFB2. A média de contaminação por aflatoxinas totais obtida foi de 7,17 µg/kg (ND-104,2 µg/kg), 1,13µg/kg (ND-7,44µg/kg) e 0,47 µg/kg (ND-0,2 µg/kg) para as amostras dos Estados do Pará, Amazonas e de São Paulo, respectivamente. Das 143 amostras coletadas, apenas 5 amostras excederam o limite máximo de aflatoxinas totais estabelecido pela União Européia e pela ANVISA (10,0ug/kg para castanhas do Brasil sem casca destinadas ao consumo direto para humanos)
Abstract: The Brazil nut (Bertholletia excelsa) is one of the most important species extracted from the Amazon forest, and is exported to several countries due to its high nutritional value. However, the low technological level of its productive chain and inadequate raw material handling favour contamination points for aflatoxin fungi producers aflatoxins. The presence of aflatoxins in Brazil nuts has been a barrier for its marketing, mainly for the export market, due to rigorous control of European countries and the United States. Therefore, the present work had the objective of investigating the incidence of fungi in Brazil nuts and evaluate the toxigenic potential of Aspergillus section flavi isolates to produce aflatoxins, as well as analyzing the presence of aflatoxins in this product. A total of 143 samples from three different states, at different stages of the Brazil nut chain was analyzed. The technique used for fungi infection analized was direct plating in DG18. The results were expressed in percentage of fungal infection. The suspected isolates were purified on Czapek yeast extract agar (CYA) and incubated at different temperature for species identification. For toxin production analysis of each isolatec Aspergillus section flavi the agar plug technique was used. For aflatoxin analysis an immunoafinity column was used for extraction and cleaning of the sample, high performance liquid for aflatoxin detection and quantification in Brazil nuts, chromatography (HPLC) with a fluorescence detector was used, coupled with the Kobracell derivatization system. Among the analyzed samples, the ones collected directly from the forests had the highest water activity, the highest fungal infection and greatest biodiversity of species. A total of 13,421 filamentous fungi were quantificated from all the samples with the most common isolated species were: Aspergillus flavus, Aspergillus nomius, Penicillium citrinum, Aspergillus tamarii, Syncephalastrum racemosum e Penicillium spp. All the 450 strains of Aspergillus nomius and 9 strains of Aspergillus parasiticus, showed 100% capacity of aflatoxin B1, B2, G1, G2 production. Out of 703 species of Aspergillus flavus isolated, 63.5% showed capacity of aflatoxin B1 e B2 production. The average of total aflatoxin contamination was: 7.17µg/kg (ND-104.2 µg/kg), 1.13µg/kg (ND-7.44µg/kg) and 0.47 µg/kg (ND-0.2 µg/kg) for samples from Pará, Amazon and São Paulo, respectively. Out of 143 analyzed samples, only 5 samples exceded the maximum level for total aflatoxins established by the European Union and ANVISA of 10 µg/kg for shelled Brazil nuts intended for direct human consumption
Mestrado
Ciência de Alimentos
Mestre em Ciência de Alimentos
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Atoui, Ali Khalil Lebrihi Ahmed Mathieu Florence. "Approche de la mycotoxinogénèse chez Aspergillus ochraceus et Aspergillus carbonarius études moléculaire et physiologique /." Toulouse : INP Toulouse, 2007. http://ethesis.inp-toulouse.fr/archive/00000383.
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Atoui, Ali Khalil. "Approche de la mycotoxinogénèse chez Aspergillus ochraceus et Aspergillus carbonarius : études moléculaire et physiologique." Toulouse, INPT, 2006. https://hal.science/tel-04575878.
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Aspergillus ochraceus et Aspergillus carbonarius, contaminants fongique fréquents dans plusieurs produits agricoles, produisent de nombreux polycétones dont les mycotoxines. Durant ce travail, la diversité des gènes de polycétones synthases (PKSs), enzymes responsables de la biosynthèse des polycétones, présentes chez ces champignons a été étudiée en utilisant des couples d’amorces spécifiques et dégénérées. Au total, neuf PKSs différentes chez Aspergillus ochraceus NRRL 3174 et cinq PKSs différentes chez Aspergillus carbonarius 2Mu134 ont été identifiées. Elles sont distribuées dans les trois principaux groupes de PKS connus chez les champignons. Un des gènes identifiés chez Aspergillus ochraceus, AoKS1, est responsable de la biosynthèse de l’ochratoxine A. D’autre part, nous avons développé un système de détection et de quantification d’Aspergillus carbonarius par PCR en temps réel en ciblant un gène de polycétone synthase. Le système développé nous a ainsi permis aussi d’avoir une estimation rapide de la contamination en ochratoxine A dans le raisin à partir de la quantification d’ADN d’Aspergillus carbonarius. Enfin, une étude physiologique menée chez Aspergillus carbonarius pour connaître la répartition d’ochratoxine A dans les spores, le mycélium et le substrat a montré que la majorité de cette toxine se trouve accumulée au niveau des spores. Les résultats ont aussi montré que la toxine accumulée se rediffuse dans le milieu et arrive après 4 heures d’incubation à un niveau plus grand que celui de la valeur initiale. Ceci montre que les spores d’Aspergillus carbonarius peuvent participer à l’augmentation de l’ochratoxine A durant la macération dans les procèdes oenologiques. L’ensemble de ces travaux se situe dans le cadre de la gestion du problème des mycotoxines dans la chaîne alimentaire.
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Khatiri, Mariam. "Vergleich zweier PCR-Nachweisverfahren zur Früherkennung einer Aspergillusinfektion bei Hochrisikopatienten manuelle DNA-Extraktion im Vergleich zur automatischen MagNa Pure DNA-Extraktion; konventionelle PCR-ELISA im Vergleich zur LightCycler R -Methode /." [S.l. : s.n.], 2006.
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Guazzelli, Luciana Silva. "Estudo etiológico, clínico, laboratorial e epidemiológico da bola fúngica pulmonar por Aspergillus spp." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/30929.
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Descrição: Bola fúngica é definida como uma macrocolônia composta por emaranhado de hifas, células inflamatórias, fibrina, muco e fragmentos de tecidos. Aspergillus fumigatus é o agente etiológico mais frequente, responsável por cerca de 90% dos casos, seguido de A niger e A flavus, respectivamente. O antecedente mais comum para o desenvolvimento da bola fúngica é cavidade secundária à tuberculose e a manifestação clínica mais presente e causadora de óbitos nesses pacientes é a hemoptise. Objetivos: Investigar as espécies de Aspergillus causadoras de bola fúngica pulmonar, determinar as condições predisponentes e/ou associadas e a comprovação laboratorial para o diagnóstico etiológico e observar a resposta as diferentes medidas terapêuticas dos pacientes com bola fúngica pulmonar. Delineamento: Foram analisados retrospectivamente, prontuários de pacientes para a caracterização da bola fúngica pulmonar por Aspergillus. Local do estudo: Laboratório de Micologia da Santa Casa Complexo Hospitalar, no período de 1980 a 2009. Pacientes e métodos: Foram incluídos neste estudo todos os pacientes com diagnóstico de bola fúngica pulmonar aspergilar de uma população de 750 casos de aspergilose, de 1980 a 2009. Os critérios para o diagnóstico foram os seguintes: isolamento da espécie de Aspergillus proveniente do material de cavidade pulmonar associado à imagem radiográfica compatível; isolamento da espécie de Aspergillus em outros materiais do trato respiratório, excluindo material da cavidade, associado ou não ao exame direto positivo; imunodifusão radial dupla positiva para Aspergillus associada ao exame de imagem compatível. Resultados: Foram incluídos 391 pacientes com bola fúngica pulmonar aspergilar, a idade variou de 18-78 anos, sendo 67,3% do gênero masculino. O diagnóstico foi baseado nos achados clínicos, radiológicos e laboratoriais. Em todos os pacientes foram detectados achados característicos de bola fúngica tanto no radiograma quanto na tomografia de tórax e bola fúngica complexa foi detectado em 97,4% da casuística. Tuberculose curada foi a principal condição predisponente (89%). Hemoptise foi manifestação clínica mais frequente (89%). A espécie A. fumigatus foi o agente etiológico mais isolado, 89,3% dos casos, seguido de A niger 7,1% e menos frequente A flavus 3,3%. A positividade no cultivo foi de 84,7% nos espécimes clínicos e a imunodifusão radial dupla de 81,6% dos pacientes. A principal medida terapêutica foi ressecção cirúrgica apresentando desfecho favorável em 88,3%. A eliminação da bola fúngica por lise espontânea ocorreu em 2,3% dos casos. Mortalidade foi atribuída à cirurgia e a hemoptise em 32,3 e 13,8%, respectivamente. Conclusões: Tuberculose curada e hemoptise é a primeira hipótese diagnóstica de bola fúngica pulmonar. O sinal radiológico indicativo de bola fúngica é cavidade contendo produto patológico com densidade de partes moles, espessamento da parede da cavidade e da pleura circunjacente. A detecção de anticorpos séricos por imunodifusão radial dupla, e o cultivo de espécimes do trato respiratório inferior determinaram A. fumigatus como o principal agente etiológico da bola fúngica pulmonar. A medida terapêutica mais utilizada nos pacientes do presente estudo foi ressecção cirúrgica, e a metade da ocorrência de óbito esteve presente nestes casos.Background: Pulmonary fungus ball is defined as a conglomeration, within a cavity of intertwined Aspergillus hyphae, inflammatory cells, fibrin, mucus and cellular debris. Aspergillus fumigatus is the most frequent etiologic agent, about 90% of cases, followed by A niger and A flavus, respectively. The most common condiction to develop fungus ball is residual cavities of healed tuberculosis, and the most prevalent clinical manifestation and cause of death is hemoptysis in these patients. Objectives: To investigate the species of Aspergillus causing pulmonary fungus ball, we compared underlying conditions, laboratory evidence to the etiological diagnosis, and response of the different therapy, and outcome of patients with pulmonary fungus ball. Design: We analyzed retrospectively the medical records of patients for the characterization of pulmonary Aspergillus fungus ball. Settings: A university-based tertiary care hospital in Porto Alegre, Rio Grande do Sul, Brazil. Patients and methods: The study included patients diagnosed with pulmonary Aspergillus fungus ball in a population of 750 cases of aspergillosis, from 1980 to 2009. The criteria for the diagnosis were: isolation of Aspergillus species from the material of the pulmonary cavity associated with the compatible radiographic image; isolation of Aspergillus species from other materials of the respiratory tract, excluding cavity material, with or without direct examination positive; double immunodiffusion positive for Aspergillus associated with compatible image. Results: We included 391 patients with pulmonary Aspergillus fungus ball, age ranged from 18 to 78 years, 67.3% were male. The diagnosis was based on clinical, radiological, and laboratory findings. In all patients we detected the characteristic findings of fungal ball, on X-ray and tomography; and complex fungal ball, on their radiological appearance, was detected in 97.4% of cases. Healed tuberculosis was the commonest pre-existing disease (89%). Hemoptysis was the major symptoms (89%). The species A. fumigatus was the most common etiologic agent, 89.3% of cases, followed by 7.1% A niger and A flavus less frequent in 3.3%. Culture was positive in 84.7% specimes, and immunodiffusion in 81.6% patients. The main treatment was surgical resection in 88.3% that had a favorable outcome. Spontaneous lysis was obtained in 2.3% of cases. Mortality was attributed to the surgery and hemoptysis in 32.3 and 13.8%, respectively. Conclusions: Patient with healed tuberculosis and hemoptysis is the first hypothesis diagnostic fungus ball. The most frequent radiological signs were rounded dense opacity surrounded with a halo of air in a thick cavity wall and thickening of the pleura over cavity. The detection of serum antibodies by double immunodiffusion, and the cultive of the lower respiratory tract specimens determined A. fumigatus as the main agent of pulmonary fungal ball. The detection of serum antibodies by double immunodiffusion, and the cultivation of the lower respiratory tract specimens determined A. fumigatus as the main agent of pulmonary fungal ball. The measure most commonly used therapy in patients of this study was to surgical resection, and half of the patients who died were in these cases.
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Weaver, Sean. "Heterokaryon incompatibility in Aspergillus fumigatus." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/heterokaryon-incompatibility-in-aspergillus-fumigatus(c0db26be-8326-4a93-8bcb-2648069e256c).html.
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Invasive aspergillosis (IA) is associated with high mortality rates and can be difficult and expensive to treat with current drugs. The drugs used to treat IA are also associated with undesirable, and often severe, side-effects of the patient. The main causative agent of this disease is the opportunistic pathogen Aspergillus fumigatus. This study identifies genes which play a role in a fungal-specific type of programmed cell death (PCD) in A. fumigatus, known as heterokaryon incompatibility. The development of drugs specifically targeting the products of these genes could lead to fewer side-effects than those arising from currently available anti-fungal drugs. The drug amphotericin B is currently used to treat IA and has been shown to induce an apoptotic-like phenotype in A. fumigatus; however, the sterols targeted are present in both fungal and mammalian cell membranes. HI is a fungal-specific self/non-self recognition system that results in rapid compartmentalisation and cell death of hyphal fusion sites if the two fusing fungi are not genetically compatible. The HI system could be exploited as a novel drug target against invasive fungal pathogens through targeting a component of the molecular pathway to induce cell death. In contrast to current drugs, novel drugs could target HI components to induce PCD without affecting non-desirable targets that cause side-effects. The non-self recognition systems used by Neurospora crassa, Aspergillus Nidulans and Podospora anserina are the well characterised, and they each differ significantly in their modes of action. BLAST searches found 30 homologues of HI genes from other the systems of characterised species in A. fumigatus, with 8 containing the fungal-specific het domain. The first assay to determine whether disruption of het genes could affect HI was to observe the barrage phenotype between incompatible A. fumigatus individuals. However, there was no barrage visible as the leading edge of colonies stopped growing when in close proximity to another colony. Instead, nitrate non-utilising (Nit) A. fumigatus mutant strains were generated using chlorate and pair-wise crosses of 46 environmentally and clinically isolates on nitrate-containing media resulted in the formation of 16 viable heterokaryons. All of the heterokaryons fell into exclusive compatibility groups where no intergroup crossing was possible. Homologous recombination was used to disrupt five of the identified het domain genes with gene replacement cassettes, generated through fusion-PCR, in an akuB(KU80Delta) A. fumigatus strain. The mutant strains displayed both detrimental growth on standard agar growth media and reduced ability to recognise non-self strains. Full and partial heterokaryons were formed during intergroup pair-wise compatibility crosses using the mutants and strains that the akuB(KU80Delta) parent strain was previously incompatible with. This was followed with a non-bias approach of gene disruption using the Fusarium oxysporum impala160 transposable element in a Nit A. fumigatus mutant. Inducing transposon mutagenesis through exposure to low temperature generated a mutant library of spores in which the transposon had disrupted different open reading frames at different locations across the A. fumigatus genome. The mutant spore library was also screened for the ability to form viable intergroup heterokaryons with strains belonging to different compatibility groups. PCR recovery and DNA sequencing was able to identify the locus of impala160 in three isolates able to form viable heterokaryons. The sequences revealed the transposable element had disrupted the same gene, AFUA_2G05070, in each of the three isolates. This gene encodes an uncharacterised conserved hypothetical protein which may be a critical component for non-self recognition in A. fumigatus HI, and a potential target for novel anti-fungal drugs to induce PCD.
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Hayer, Kimran. "Germination of Aspergillus niger conidia." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14292/.
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Aspergillus niger is a black-spored filamentous fungus that forms asexual spores called conidospores (‘conidia’). Germination of conidia, leading to the formation of hyphae, is initiated by conidial swelling and mobilisation of endogenous carbon and energy stores, followed by polarisation and emergence of a hyphal germ tube. These morphological and biochemical changes which define the model of germination have been studied with the aim of understanding how conidia sense and utilise different soluble carbon sources for germination. Microscopy and flow cytometry were used to track the morphological changes and results showed that the germination of A. niger conidia was quicker and more homogenous in rich media than in minimal media. The germination of conidia was also shown to be quicker in the presence of D-glucose than D-xylose. In the absence of a carbohydrate, no visual indicators of germination were evident. Added to this, the metabolism of internal storage compounds was shown to only occur in the presence of a suitable carbon source. Specific environmental carbon sources may therefore serve as triggers of germination, i.e. to initiate the catabolism of stores such as D-trehalose and the swelling of conidia. Studies carried out using D-glucose analogues identified the structural features of sugars that trigger or support conidial germination. These studies showed that the arrangement of atoms on carbons 3 and 4, on the pyranose ring structure of D-glucose, are essential to serve as a trigger of germination. The trigger step preceeds, and is separate from, the energy generation step that supports the continued outgrowth. Transcriptomic studies found that the most significant changes were associated with the breaking of dormancy. The data also revealed that fermentative metabolism present at the early stages of spore germination is rapidly replaced by respiratory metabolism.
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Masson, Corinne. "Transposition hétérologue chez Aspergillus nidulans." Paris 11, 2001. http://www.theses.fr/2001PA112203.
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Robertson, Maura Diane. "Host defences against Aspergillus fumigatus." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/26892.
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The potential of the filamentous fungus Aspergillus fumigatus to act as an opportunistic pathogen may be related to its ability to resist the host defence network. Whilst phagocytic cells are clearly important in host defences against invading microorganisms their precise role in the killing of A. fumigatus remains undefined. The purpose of this study was to examine the basic interactions between phagocytic cells, from humans and rodents, with spores of A. fumigatus. In particular the mechanisms whereby phagocytic cells bind and kill spores of A. fumigatus, when compared with the relatively non-pathogenic fungus Penicillium ochrochloron were investigated. In order to investigate why people with asthma may develop some hypersensitivity reactions to A. fumigatus, in particular, rather than to the many other fungi in the atmosphere, the possibility that there may be a defect in the handling of the fungus by such patients has been tested. A comparison of the fungal handling by phagocytes from asthmatic patients, both sensitised and unsensitised to A. fumigatus with phagocytes from non-asthmatic subjects has been made. The principal findings from this study are that spores of A. fumigatus bind to the surface of the phagocytic cell yet are relatively resistant to phagocytosis. The spores also fail to trigger the phagocytic cells into releasing the potentially microbicidal reactive oxygen intermediates. These results may be related to a further finding which is that spores of A. fumigatus release a low molecular weight substance (diffusate) which interferes with various aspects of phagocytic cell activation. Spore diffusates were shown to inhibit the phagocytosis of radiolabelled antibody-coated sheep red blood cells and to suppress the spontaneous release of reactive oxygen intermediates by Corynebacterium parvum stimulated mouse peritoneal exudate cells. In addition spores diffusates inhibited the ability of phagocytic cells to spread on glass and reduce the number of phagocytic cells migrating towards a known chemoattractant. Studies on spore killing showed that spores of A. fumigatus opsonised in autologous serum were more resistant to killing by phagocytic cells from humans and rodents than similarly opsonised spores of P. ochrochloron. However, the ability of the phagocytic cells to kill spores of A. fumigatus was substantially increased when the spores were opsonised in sera which had been heat-treated for 30 minutes at 56?C. No increased killing was found with P. ochrochloron. People with asthma sensitised to A. fumigatus showed significant differences in their handling of A. fumigatus in vitro when compared with the control group. Monocytes from these sensitised patients killed significantly fewer spores of A. fumigatus (opsonised in auto? logous sera) whilst their polymorphonuclear leucocytes killed significantly more. No such differences were found for P. ochrochloron. The work reported in this Thesis has given us a clearer understanding of why Aspergillus fumigatus is an important cause of disease in man, and how the defence mechanisms that it has evolved in its natural environment the soil, enable it to act as a saprophyte or parasite in the lungs of humans and animals. The results also suggest a mechanism whereby heat-labile serum components may be an advantage to the survival of the fungus, thus perhaps explaining why it may be a particular problem in the airways of asthmatic patients.
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Rodriguez, Eric. "Aspergillus fumigatus : variabilité génétique des souches isolées au cours d'aspergilloses pulmonaires et interaction avec les macrophages in vitro." Montpellier 1, 1996. http://www.theses.fr/1996MON13518.
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O'Connell, Matthew J. "The structure and regulation of aldehyde dehydrogenase encoding genes in Aspergillus niger and Aspergillus nidulans /." Title page, contents and abstract only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09pho183.pdf.
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Oliveira, Alfredo Luis Zangarini Grisi de. "Interação genica e produção de glicoamilase em hibridos interespecificos de Aspergillus niger e Aspergillus awamori." [s.n.], 1991. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317241.
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Orientador : Renato Bonatelli JrDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Mestrado
Genetica
Mestre em Ciências Biológicas
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Vialta, Airton. "Genetica e produção de amiloglicosidase em Aspergillus awamori e no hibrido interespecifico com Aspergillus niger." [s.n.], 1987. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317246.
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Orientador : Renato Bonatelli JuniorDissertação (mestrado) - Universidade Estadual de Campinas. Instituto de Biologia
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Resumo: O presente trabalho teve como objetivos principais, verificar a ocorrência do ciclo parassexual em Aspergillus awamori, testar a produção de amiloglicosidase dos derivativos, mutantes e diplóides obtidos e realizar o cruzamento interespecífico com A. niger. Além desses, estudos foram desenvolvidos com a instabilidade apresentada por A. awamori.. A linhagem NRRL 3112 segrega conídios pro e forma setores espontaneamente. Este comportamento não seria o esperado para um clone e sugere a existência de heterozigose para as características estudadas, a qual poderia estar contida numa duplicação parcial ou total de genoma. Mutantes auxotróficos e morfológicos de Á. awamori foram conseguidos utilizando-se os métodos de isolamento total e de enriquecimento por filtração. Este último mostrou freqüências de isolamento 12 vezes maiores. Mutantes resistentes ao Brometo de Etídio também foram isolados, mas somente após indução com luz ultravioleta. Os mutantes foram utilizados em cruzamentos que permitiram verificar a ocorrência do ciclo parassexual. Através da análise dos segregantes, pode ser evidenciada ligação entre os genes etbl, grel bwnl; morl, arg2 e leul, mor2. O gene pabl segregou independentemente e, assim, foi possível sugerir 4 como o numero mínimo de grupos de ligação nessa espécie. Entre os critérios não geneticos utilizados na caracterização, o diâmetro de conídios e o tratamento com Benlate mostraram-se eficientes para separar haplóides de diplóides. O método de extração e quantificação de DNA por núcleo também foi adequado para esse fim. Com relação ã enzima, o primeiro passo foi averiguar se o método empregado estava medindo a atividade da amiloglicosidase, fato que foi confirmado fazendo o teste com o inibidor e a dextrina limite. Foi constatada uma relação inversamente proporcional entre a porcentagem de segregação de conídios pro e a produção de amiloglicosidase. Só foi possível obter o cruzamento entre A. awamori e Á. niger através de fu são de protoplastos. A freqüência de formação de colônias prototróficas foi relativamente baixa, situando-se na faixa de 0,6%, possivelmente devido ao pequeno número de protoplastos utilizados para a fusão e a um provável efeito tóxico diferencial do agente fusogênico utilizado. As colônias prototróficas isoladas inicialmente puderam ser classificadas como heterocarióticas. A partir destas, o produto de fusão híbrido foi obtido na forma de setores que exibiam complementação entre as marcas genéticas das parentais. Através da análise do híbrido, pode ser evidenciada ligação entre os genes nicl, 0lv2, bwnl, amy, pro. Houve distribuição ao acaso dos grupos de ligação, semelhante ao esperado para um diplóide intra - específico sugerindo alto grau de homologia cromossômica entre as duas espécies. Os mesmos critérios de caracterização utilizados com sucesso para separar linhagens haplóides de diplóides. nos cruzamentos intra-específicos foram adotados e também nesse caso mostraram resultados satisfatórios
Abstract: The present work with Aspergillus was done aiming to study the following: 1- Occurrence of the parasexual cycle;2- Occurrence of interspecific hybridization with A. niger.3- Amyloglucosidase production of the parental and derived strains, including auxotrophic mutants, diploids and the interspecific hybrid. During the first stage of the work, it was observed that the NRRL 3112 strain of A. awamori is unstable because it spontaneously segregates pro conidia (deficient for proline synthesis) and produces sectors. The last characteristic is also observed in pro derivatives and it was supposed that it is independent from pro conidia segregation. These characteristics are not expected from a clone and together with other evidences (Benlate segregation, differential susceptibility to acetone, variation in number of nuclei per conidia and conidial diameter), it was suggested that there is a partial or total duplication of the genome. Auxotrophic and morphological mutants of A. awamori were induced by ultraviolet light and selected by using total isolation and filtration enrichment methods. An increase of 12 times in the mutant frequency was observed when the last method was employed. Ethidium bromide resistant mutants were also isolated only after ultraviolet induction. Diploid strains were readily obtained and could easily be' separated from haploid strains by conidia diameter, Benlate segregation and nuclear DNA content. Segregation analysis indicated linkage between etb1 gre1 bwn1, mor1, arg1 and leu1, mor2. Because pab1 marker segregated independently from all others it was suggested at least 4 linkage groups for A. awamori. Only heterokaryotic colonies were detected when A. awamori and A. niger protoplasts were fused and plated in selective medium. The low frequency (0,6%) and the heterokaryotic nature of the colonies could probably be attributed to: 1) low protoplasts number and 2) toxic effect to the fusogenic agent to A. niger protoplasts. Hybrid colonies were isolated after several transfers in selective medium. The hybrid nature of these colonies was established by the same criteria used in the intraspecies crossing. Segregation analysis indicated a high level of chromosomal homology between the 2 species and it was possible to suggest linkage between nic1 olv2 genes of niger and bwn, amy, pro of awamori. As it was evident from the use of limit dextrin and a specific inhibitor. glucoamylase is the main enzyme activity detected by the usual assay procedure. It has also been detected that high. frequency of pro conidia in A. awamori is correlated with the low level of enzyme production
Mestrado
Mestre em Genetica
38
Mondon, Philippe. "Polymorphisme génétique et virulence d'Aspergillus fumigatus : étude de souches invasives et non invasives par méthodes moléculaires et corrélation avec un modèle murin d'aspergillose pulmonaire invasive : caractérisation moléculaire de souches invasives au cours d'une enquête européenne multicentrique." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE18009.
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Possari, Camila Kopezky 1987. "Atividade de óleos essenciais sobre espécies de Aspergillus spp. aflatoxigênicas isoladas de castanha do Brasil." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255113.
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Orientador: Marta Cristina Teixeira DuarteDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A castanha do Brasil (Bertholletia excelsa H.B.K.) é a segunda mais importante fonte extrativista da floresta amazônica. Desta forma, não são utilizados defensivos químicos e a produção da castanha do Brasil é considerada orgânica tendo sua extração ambientalmente correta, porém este baixo nível tecnológico favorece o crescimento de fungos potencialmente produtores de micotoxinas como os do grupo Aspergillus section flavi. Visando reduzir esta contaminação, uma das possibilidades é a utilização de óleos essenciais, que apresentam propriedades antimicrobianas. Assim, o objetivo do presente trabalho foi avaliar a atividade antifúngica de 11 óleos essenciais de espécies medicinais e aromáticas sobre cepas aflatoxigênicas de A. flavus, A. nomius e A. arachidicola isoladas de castanha do Brasil. O ensaio de microdiluição mostrou que os óleos que apresentaram melhor atividade antifúngica contra estes os isolados foram Cinnamomum burmannii e Eugenia caryophyllata, com MIC de 250 'mu'g/mL e 500 'mu'g/mL, respectivamente. A inibição do crescimento micelial dos fungos foi melhor quando estes foram submetidos à ação por contato com os óleos essenciais, do que por ação de seus compostos voláteis, sendo as concentrações referentes às de MIC capazes de inibir totalmente o crescimento dos fungos. A produção de aflatoxina por A. flavus foi inibida somente pelo óleo essencial de E. caryophyllata, na concentração de 500 'mu'g/mL. Ensaios in vivo conduzidos com a casca da castanha do Brasil mostraram que o óleo essencial de C. burmannii inibiu o fungo a 500 'mu'g/mL e propiciou maior redução na porcentagem de infecção pelos isolados de A. flavus. Quanto aos isolados de A. nomius e A. arachidicola, a menor porcentagem de infecção foi obtida após tratamento com o óleo essencial de E. caryophyllata na concentração de 1000 'mu'g/mL. Os óleos de E. caryophyllata e C. burmanni mostraram ser alternativas naturais para controle do crescimento de A. flavus, A. nomius e A. arachidicola e da produção de aflatoxinas por A. flavus, através da ação na redução da contaminação fúngica das castanhas do Brasi
Abstract: The Brazil nut (Bertholletia excelsa H.B.K.) is the second most important forest source of the Amazon rainforest. Thus, no chemical pesticides are used and the production of Brazil nuts is considered organic and an environmentally friendly extraction. However, this low technological level favors the growth of potentialy mycotoxin producing fungi such as Aspergillus section flavi. In order to reduce this contamination, one possibility is the use of essential oils that exhibit antimicrobial properties. The objective of this study was to evaluate the antifungal activity of 11 essential oils of medicinal and aromatic species on aflatoxigenics strains of Aspergillus flavus, A. nomius and A. arachidicola isolated from Brazil nuts. The microdilution assay showed that the oils from Cinnamomum burmannii and Eugenia caryophyllata presented the best antifungal activity against all isolates, with MIC of 250 'mu'g/mL and 500 'mu'g/mL, respectively. The inhibition of mycelial growth of the fungi was better when submitted to action by contact than by action of oils volatile compounds, with concentrations of MIC able to completely inhibit the growth of fungi. The aflatoxin production was inhibited only by E. caryophyllata essential oil at a concentration of 500 'mu'g/mL . In vivo assays conducted with shells of Brazil nut showed that the essential oil of C. burmannii at 500 'mu'g/mL provided greater reduction in the percentage of infection by A. flavus isolates. As the isolates of A. nomius and A. arachidicola, the infection rate was lower after the treatment with the essential oil of E. caryophyllata in the concentration of 1000 'mu'g/mL. The essential oils of E. caryophyllata and C. burmannii showed to be natural alternatives for controlling the growth of A. flavus, A. nomius and A. arachidicola and aflatoxin production by A. flavus, through the reduction of the fungal contamination of Brazil nuts
Mestrado
Ciência de Alimentos
Mestra em Ciência de Alimentos
40
Bernard-Cardona, Muriel. "Protéines et paroi chez Aspergillus fumigatus." Phd thesis, INAPG (AgroParisTech), 2003. http://tel.archives-ouvertes.fr/tel-00005702.
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La paroi du champignon filamenteux A. fumigalus conditionne la croissance et est responsable du maintien de l'intégrité cellulaire lors de l'infection. Les protéines de la paroi de ce champignon filamenteux n'avaient pas été étudiées jusqu'à présent alors qu'elles semblent jouer un rôle essentiel dans la structuration de la paroi de la levure modèle S. cereviciae. Une approche essentiellement biochimique a permis de caractériser les protéines associées à la paroi de A..fumigatus. La majorité des protéines pariétales chez A. fumigatus sont des protéines solubles. Une seule protéine est relarguée à partir de la paroi par un traitement f3- (1 .3) glucanase : c'est une phosphatase acide qui possède une ancre GPl et dont l'expression est réprimée en présence de phosphate inorganique. Par ailleurs, une étude des protéines GPl chez A. fumigatus par génomique comparative a montré que les protéines GPI décrites comme associées de façon covalente à la paroi chez la levure n'ont pas d'homologue chez A. fumigatus. Ainsi. l'organisation des protéines au sein de la paroi de A..fumigatus est différente de celle de la levure : les protéines pariétales ne semblent pas avoir un rôle essentiel dans l'élaboration de la paroi. Ensuite, une nouvelle famille de glycoprotéines portant un N-glycane lié à un galactofuranose en position terminale a été décrite. Cette famille comprend une phospholipase C, une phosphatase alcaline et une phytase. Enfin, une analyse morphologique de deux mutants chitine synthase et gluconosyltransférase a permis d'associer la réduction de la croissance à un hyper-branchement du mycélium et à une diminution de la taille de la cellule apicale sans que l'organisation globale des polysaccharides pariétaux et le taux de croissance spécifique soient affectés.
41
Melloul, Elise. "Aspergillose aviaire : développement d’un modèle d’aspergillose chez la dinde (Meleagris gallopavo) et évaluation de l’efficacité de l’énilconazole." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1183/document.
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Aspergillus fumigatus est un agent pathogène respiratoire majeur chez les oiseaux d’ornement comme de production. L’aspergillose qui peut être responsable de mortalités importantes et de chutes de performances est difficile à traiter. Nous avons développé un modèle d’aspergillose aiguë chez le dindonneau en inoculant différents lots d’oiseaux âgés de moins d’une semaine via une aérosolisation intratrachéale de doses croissantes de conidies (105 à 108/animal) en utilisant un MicroSprayer®. Le développement de la masse fongique a été évalué par qPCR, dosage du galactomannane (GM), culture fongique et évaluation histopathologique dans le but de comparer les résultats obtenus en fonction du nombre de conidies inoculées. Une mortalité significative a été observée dans les 4 jours suivant l’inoculation uniquement pour l’inoculum le plus concentré. Les résultats des différents marqueurs du développement du champignon (culture, qPCR et GM), sont très bien corrélés avec la dose de l’inoculum administrée. Les moyennes d’équivalents conidies/g de poumon obtenues par qPCR étaient 1,3 log10 plus importantes que les numérations obtenues par culture sur gélose. Ce nouveau modèle incluant une combinaison inédite de biomarqueurs chez la dinde a été utilisé pour évaluer l’efficacité de l’énilconazole, seule molécule utilisée en élevage avicole pour lutter contre l’aspergilloseAspergillus fumigatus remains a major respiratory pathogen in both ornamental and poultry. Aspergillosis can be responsible for high mortality rates and induces significant economic losses, particularly in turkey production, and it is still difficult to treat. We developed a new model of acute aspergillosis in young turkeys by inoculating few-days-old turkeys via intratracheal aerosolization with increasing concentrations (105 up to 108) of conidia using a MicroSprayer® device. The fungal burden was assessed and compared by real-time PCR, galactomannan (GM) dosage, fungal colony (CFU) counting and by histopathology. Early death occurred in the first 96 h post-inoculation only at the highest inoculum dose. We observed a correlation between inoculum size and results obtained by real-time PCR, GM dosage and CFU counting. The mean fungal burden detected by qPCR was 1.3 log10 units higher than the mean values obtained by CFU measurement. Furthermore, this new model, with its unique combination of markers, has been used to evaluate the efficacy of enilconazole
42
Wang, Dong ying. "Diversité génétique et sensibilité aux antifongiques d’isolats d’Aspergillus spp. provenant d’élevages aviaires du Guangxi , Chine." Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0040/document.
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Les champignons du genre Aspergillus sont des moisissures banales de l'environnement. Elles sont présentes dans le sol et sur des végétaux en décomposition. Les Aspergillus se propagent par l'intermédiaire de spores microscopiques en suspension dans l'air. L'Homme et les animaux sont exposés en permanence aux spores aspergillaires mais les défenses immunes empêchent leur développement dans l'organisme. Lorsque ces défenses sont amoindries, une aspergillose est possible. Dans ce cas, Aspergillus fumigatus et A. flavus sont le plus souvent incriminés. Les oiseaux sont beaucoup plus sensibles que les mammifères et l'environnement représenté par les élevages aviaires est propice à la prolifération des moisissures du genre Aspergillus. L'objectif de ce travail de thèse a été de caractériser la diversité génétique et la sensibilité aux antifongiques d'isolats d'Aspergillus provenant d'élevages aviaires dans la province du Guangxi en Chine. La première partie de la thèse est une analyse bibliographique sur les champignons du genre Aspergillus, les aspergilloses et les caractéristiques de l'élevage aviaire en Chine. Une première enquête a été réalisée dans 3 élevages près de la ville de Nanning et dans un élevage (incluant un éclosoir) à proximité de la ville de Guilin. Des écouvillonnages pharyngés et des prélèvements d'air ont été réalisés pendant plusieurs semaines. Des prélèvements ont également été faits sur des œufs dans l'éclosoir. Cette enquête a montré que le niveau de contamination fongique dépendait du type d'élevage. De nombreux isolats fongiques ont pu être collectés : 188 isolats d'A. fumigatus et 159 isolats d'A. flavus. La seconde partie du travail expérimental a porté sur la caractérisation de la diversité génétique d'A. fumigatus et d'A. flavus. Pour cela, la technique MLVA (multiple locus VNTR analysis) a été utilisée. Pour A. flavus, 8 marqueurs VNTR (variable-number tandem-repeat) ont été sélectionnés et une réaction PCR multiplex a été mise au point. Au total, 91 isolats d'A. flavus, incluant 6 souches de référence, ont été caractérisées avec le panel des 8 marqueurs VNTR. Cette analyse a permis de définir 78 génotypes distincts et un index de discrimination de 0,993. L'analyse de 188 isolats d'A. fumigatus avec 10 marqueurs VNTR a permis de définir 142 génotypes distincts. Certains génotypes d'A. flavus ou d'A. fumigatus sont clairement regroupés dans le nuage de point généré par l'analyse MST (minimum spanning tree). La troisième partie du travail expérimental a porté sur la sensibilité aux antifongiques de 177 isolats d'A. fumigatus. Ces isolats ont été récupérés dans des élevages aviaires en Chine et en France. Les isolats de Chine sont pour la plupart sensibles avec des valeurs minimales inhibitrices (vis-à-vis de l'itraconazole) comprises entre 0,38 et 0,75 µg/mL. Les isolats de France sont pour la plupart sensibles avec des valeurs minimales inhibitrices (vis-à-vis de l'itraconazole) comprises entre 0.19 and 1 µg/mL. Quatre souches ont été considérées comme résistantes : 2 souches provenant de deux élevages en Chine et 2 souches provenant de deux élevages en France. Des mutations sur le gène Cyp51A ont été détectées pour 11 isolats (3 résistants et 8 sensibles). Vingt et une mutations nucléotidiques ont été identifiées. Onze de ces mutations sont silencieuses et 9 sont à l'origine d'un changement de la composition de la protéine. Sept substitutions ont déjà été décrites dans la littérature ; les mutations A116R, E130D et Q131H sont originalesFungi of the genus Aspergillus are moulds, which occur most frequently in soil, water and decaying vegetation. They sporulate abundantly and the spores are easily dispersed into the environment by air. As a result of this ubiquitous presence, animals and people are constantly exposed to Aspergillus spores. Aspergillus fumigatus and A. flavus are recognized as predominant causes of fungal diseases in humans and wide range of animals. Birds are much more sensitive that mammals and in avian farms, environmental conditions are favorable to the development of many fungal species, including Aspergillus spp. The objective of the present study was to assess the genetic diversity and antifungal susceptibility of Aspergillus isolates from avian farms in Guangxi, China. The first part of the experimental work related the evolution of fungal contamination in 3 avian farms near the city of Nanning and one farm (including a hatchery) near the city of Guilin. Pharyngeal swabs and air samples were collected during several weeks and 3 cycles of hatching were monitored. The average contamination level with Aspergillus spp. and Mucorales was significantly different according to the farms. The survey allowed to collect a total number of 188 A. fumigatus and 159 A. flavus isolates. The second part of the work was about the genetic diversity of A. fumigatus and A. flavus. For that purpose, the Multiple Locus Variable-number tandem-repeat (VNTR) Analysis was specifically developed and used. For A. flavus, 8 VNTR markers were selected and a multiplex reaction was designed. A total number of 91 A. flavus isolates, including 6 reference strains were typed with the panel of 8 VNTRs. This analysis yielded 78 different genotypes, which corresponds to a combined loci index of 0.993. Among all genotypes, 71 were only found once. The analysis of 188 A. fumigatus isolates using 10 VNTR markers led to the resolution of 142 distinct genotypes. Clusters of A. flavus or A. fumigatus isolates could be defined by using the graphing algorithm Minimum Spanning Tree. The third part of the experimental work was about the antifungal susceptibility of 177 A. fumigatus isolates collected in avian farms in China and France. Most of the isolates from China were susceptible to itraconazole with a Minimum Inhibitory Concentration (MIC) comprised between 0.38 and 0.75 µg/mL. Most of the isolates from birds and avian farms in France were susceptible to itraconazole with a MIC comprised between 0.19 and 1 µg/mL. MIC values of isolates collected in farms with antifungal chemoprophylaxis were not higher than those of isolates collected from birds (that never received antifungal drugs before the sampling). Susceptibility testings demonstrated that 4 isolates should be considered as resistant to itraconazole: (2 isolates from avian farms in Guangxi, China and 2 isolates from avian farms in France). A modification of the Cyp51A sequence was identified in 11 isolates (3 azole-resistant and 8 azole-susceptible isolates). Twenty-one nucleotidic mutations were detected. Eleven of these mutations were silent and 10 yielded to amino acid substitutions. Seven of these substitutions had already been described whereas mutations A116R, E130D and Q131H were original
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Gurkok, Sumeyra. "Heterologous Expression, Characterization, And Optimization Of Production Of Alpha-galactosidase From Aspergillus Fumigatus In Aspergillus Sojae." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614859/index.pdf.
Full textAbstract:
&alpha-Galactosidase is an exo-glycosidase that hydrolyses non-reducing, &alpha
-1,6-linked &alpha
-galactose units from oligosaccharides, galactomannans, and galactolipids. &alpha
-Galactosidase activity has biotechnological, industrial, and medical importance. &alpha
-Galactosidase from A. fumigatus IMI 385708, in particular, can catalyse unique hydrolysis and transgalactosylation reactions on polymeric substrates. In this study, &alpha
-galactosidase of the human pathogen A. fumigatus IMI 385708 was first produced in a GRAS organism, Aspergillus sojae. For this aim, &alpha
-galactosidase gene (aglB) of A. fumigatus IMI 385708 was ligated onto pAN52-4 vector (Acc. No: Z32699) and transformed into Aspergillus sojae ATCC11906, under the control of the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (gpdA) of A. nidulans and the signal sequence of glucoamylase gene (glaA) of A. niger. This allowed high level of &alpha
-galactosidase production on glucose instead of locust bean gum (2.45 U/mL), corresponding to a 3-fold increase in volumetric production. Next, using response surface methodology, carbon and nitrogen sources and agitation speed were optimized (10.5% molasses (w/v)
1.3% NH4NO3 (w/v)
276 rpm). Compared to non-optimized cultivation, a further 4-fold increase in &alpha
-galactosidase production (10.4 U/mL) was achieved. Recombinant &alpha
-galactosidase was purified 18.7-fold using Anion Exchange and Hydrophobic Interaction Chromatography with an overall yield of 56% and 64.7 U/mg protein. The Vmax and Km values for the hydrolysis of p-nitrophenyl &alpha
-D-galactopyranoside were 78 U/mg protein and 0.45 mM, respectively. Optimum pH and temperature for &alpha
-galactosidase activity were between pH 4&ndash
6 and 50&ndash
60 °
C, respectively. Among the tested chemical agents, Ag+, Hg2+, and Fe2+ drastically decreased the activity, while biotin, I+1, Mn+2, Pb+2, Li+1, and Mg+2 enhanced between 12&ndash
29%. To analyse the influence of osmotic stress as a means of further inducing &alpha
-galactosidase production, salt was added into the complete growth medium. In addition to enzyme production, fungal growth and morphology were analysed for both &lsquo
salt-adapted&rsquo
and &lsquo
salt non-adapted&rsquo
A. sojae Ta1 cells in the presence of KCl, MgCl2, MgSO4, NaCl, and Na2SO4 at 1 M and 2 M. Accordingly, 3-fold increase in &alpha
-galactosidase production was achieved by non-adapted cells in the presence of 1 M NaCl. Exposure of A. sojae Ta1 cells to salt resulted in predominantly mycelial form, rather than the pellet form observed under normal conditions. Finally, the transgalactosylation ability of &alpha
-galactosidase was studied. &alpha
-Galactosidase efficiently catalysed galactose transfer to different monosaccharides and disaccharides in the presence of pNP&alpha
Gal as monitored by TLC, ESI-MS, and HPLC.
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Gouvêa, Paula Fagundes de. "Estudos genéticos e moleculares da produção de celulases e hemicelulases em Aspergillus nidulans e Aspergillus niger." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/17/17131/tde-27102013-220538/.
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O mundo se depara atualmente com a perspectiva de um significativo aumento na demanda por etanol combustível. O bagaço de cana está entre os maiores subprodutos agroindustriais no Brasil, sendo uma das alternativas na utilização para a produção do etanol de segunda geração. A degradação do bagaço de cana requer a ação de muitas enzimas diferentes que são reguladas transcripcionalmente. Considerando-se que o custo de celulases e hemicelulases contribuem substancialmente no preço do bioetanol, novos estudos visando o entendimento da eficiência e produtividade de celulases são de grande importância. Para entender como melhorar coquetéis de enzimas que podem hidrolizar o bagaço de cana-de-açúcar pré-tratado, uitlizou-se um experimento de genômica para investigar-se quais genes e vias são transcripcionalmente moduladas durante o crescimento de A. niger em bagaço de cana-de-açúcar explodido. Neste trabalho foram identificados genes que codificam celulases e hemicelulases com aumento da expresão durante o crescimento em bagaço de cana-de-açúcar explodido. Foi também realizada a determinação do acúmulo de mRNA de diversos genes que codificam transportadores para verificar se estes eram induzidos por xilose e por depedência de glicose. Foram identificados 18 genes que corresponde a 58% de celulases preditas em A. niger e 21 genes que correponde a 58% de hemicelulases preditas em A. niger os quias foram altamente expressos durante o crescimento em bagaço de cana-de-açúcar explodido. Foi investigado também o papel central realizado pelas proteínas quinases e fosfatases não essenciais (NPKs e NPPs, respectivamente) quando em presença de celulose como fonte de carbono, no sensoriamento do estado energético e na subsequente via de sinalização no fungo filamentoso modelo Aspergillus nidulans. O estudo com A. nidulans identificou 11 quinases e 7 fosfatases não essências, NPKs e NPPs, respectivamente, envolvidas na produção de celulases e em alguns casos, na produção também de hemicelulases. O envolvimento destas NPKs identificadas na resposta induzida por avicel e na desrepressão foram acessados pela análise do transcriptoma da cepa selvagem e por microscopia de fluorescência através da cepa de fusão CreA::GFP expressa no selvagem e no background dos mutantes de NPKs. A ausência das quinases snfA e schA reduziu dramaticamente a resposta transcricional induzida por celulose incluindo a expressão de enzimas hidrolíticas e transportadores, enquanto que a ausência de snfA resultou em uma quase completa modulação gênica induzida por celulose. O mecanismo pelo qual essas duas quinases controlam a transcrição gênica foi identificado, onde os dois mutantes de quinases foram capazes de desbloquear o CreA mediante a repressão catabólica do carbono (CCR), sob condições de desrepressão, como em baixa presença de carbono ou crescimento em celulose. Desta forma, este trabalho abriu novas possibilidades para o entendimento da sacarificação do bagaço de cana-de-açúcar por hidrolases de A. niger e para a construção de coquetéis de enzimas mais eficientes para a obtenção do etanol de segunda geração. Também possibilitou a identificação de muitas quinases e fosfatases envolvidas no sensoriamento do carbono e do estado energético, as quais demonstraram papéis sobrespostos e distintos de snfA e schA na regulação da desrepressão de CreA e na produção de enzimas hidrolíticas em A. nidulans.The world today is faced with the prospect of a significant increase in demand for fuel ethanol. Sugarcane bagasse is among the largest agro-industrial by-products in Brazil, one of the alternatives in use for the production of second generation ethanol. Degradation of sugarcane bagasse requires the action of many different enzymes which are transcriptionally regulated. Considering that the costs of cellulases and hemicellulases contribute substantially to the price of bioethanol, new studies aimed at understanding and improving cellulase efficiency and productivity are of paramount importance. To understand how to improve enzymatic cocktails that can hydrolyze pretreated sugarcane bagasse, we used a genomics approach to investigate which genes and pathways are transcriptionally modulated during growth of A. niger on steam-exploded sugarcane bagasse. We also sought to determine whether the mRNA accumulation of several steam-exploded sugarcane bagasseinduced genes encoding putative transporters is induced by xylose and dependent on glucose. We identified 18 genes that corresponds to 58% of A. niger predicted cellulases and 21 genes that correspond to 58% of A. niger predicted hemicellulases, that were highly expressed during growth on sugarcane bagasse. The central role performed by nonessential protein kinases (NPK) and phosphatases (NPP) when grown on cellulose as a sole carbon source, in the sensing energetic status and the subsequent signalling pathways was assessed in the model filamentous fungus Aspergillus nidulans. This study identified multiple kinases and phosphatases (NPKs and NPPs, respectively) involved in the sensing of carbon or energetic status, while demonstrating the overlapping and distinct roles of snfA and schA in the regulation of CreA derepression and hydrolytic enzyme production in A.nidulans. The involvement of the identified NPKs in avicel-induced responses and CreA derepression was assessed by genome-wide transcriptomics and fluorescent microscopy of a CreA::GFP fusion proteinexpressed in the wild-type and NPK-deficient mutant backgrounds. The absence of either the schA or snfA kinase dramatically reduced cellulose-induced transcriptional responses including the expression of hydrolytic enzymes and transporters, while the absence snfA resulted in a near complete loss of wild-typecellulose-induced gene modulation. The mechanism by which these two NPKs controlled gene transcription was identified, as neither of NPK-deficient mutants were able to unlock CreA-mediated carbon catabolite repression, under derepressing conditions, such as carbon starvation or growth on cellulose. Our presently reported work opens new possibilities for understanding sugarcane biomass saccharification by A. niger hydrolases and for the construction of more efficient enzymatic cocktails for second-generation bioethanol. This work also enable the identification of multiple kinases and phosphatases involved in the sensing of carbon or energetic status, while demonstrating the overlapping and distinct roles of snfA and schA in the regulation of CreA derepression and hydrolytic enzyme production in A.nidulans.
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Yeghen, Tullie. "Diagnosis and epidemiology of Aspergillus fumigatus and Aspergillus flavus infections by molecular techniques in haematology patients." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395541.
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Haynes, Kenneth Adrian. "The role of Aspergillus antigens and specific anti-Aspergillus antibodies in the diagnosis of invasive aspergillosis." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46811.
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Mulinari, Evandro José. "Expressão heteróloga em Aspergillus nidulans e caracterização bioquímica e estrutural de uma endoglucanase de Aspergillus terreus." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-07052015-085141/.
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A degradação enzimática rápida, eficiente e robusta de polissacarídeos derivados de biomassa lignocelulósica é atualmente um grande desafio na produção de biocombustíveis e considerada uma alternativa viável e promissora para se enfrentar a crise energética mundial e diminuir a dependência das fontes fósseis de energia. O bagaço de cana-de-açúcar no Brasil é a principal matéria lignocelulósica sustentável de grande potencial para a produção do etanol de 2ª geração. O principal requisito para a consolidação dessa abordagem é a disponibilidade de enzimas que hidrolisam a celulose, hemicelulose e outros polissacarídeos em açúcares fermentescíveis e em condições adequadas para a utilização industrial. O presente estudo visou à caracterização molecular, estrutural e funcional da endoglucanase GH12 do fungo Aspergillus terreus (AtGH12) por diferentes técnicas. O gene que codifica para essa enzima foi clonado e expressado no fungo filamentoso A. nidulans linhagem A773. A cepa com maior secreção foi selecionada e a sequência da enzima confirmada por espectrometria de massas MALDI TOF MS. Posteriormente, através de estudos funcionais de parametrização enzimática como pH e temperatura ótimos, estabilidade térmica, efeitos supressores e potencializadores de aditivos, a enzima AtGH12 foi caracterizada bioquímica e fisicamente. A espectrometria de massas do substrato hidrolisado pela catálise enzimática foi tomada como uma forma de investigar o padrão de clivagem da hidrólise e estudo do reconhecimento enzima/substrato para a AtGH12. As caracterizações estruturais das enzimas recombinantes obtidas utilizando as técnicas de espalhamento dinâmico de luz, dicroísmo circular, espalhamento de raios X a baixo ângulo e gel nativo serviram para determinação do enovelamento e estado oligomérico em solução da AtGH12. Com o intuito de fornecer subsídios para o desenvolvimento de coquetéis enzimáticos mais eficazes para hidrólise da biomassa lignocelulósica, a atividade da AtGH12 foi avaliada frente ao bagaço de cana-de-açúcar pré-tratados pelos processos hidrotérmicos e organossolve. Posteriormente, o seu grau de sinergismo nesse tipo de substrato foi determinado com o coquetel enzimático comercial Acellerase®.Fast, more efficient and robust enzymatic degradation of lignocellulosic biomassderived polysaccharides is currently a major challenge in the production of biofuels and considered a feasible and promising alternative to confront the global energy crisis and reduce the dependence on fossil energy resources. The sugarcane bagasse in Brazil is the most abundant and sustainable lignocellulosic material for the production of 2nd generation ethanol. The main requirement for the consolidation of this approach is the availability of enzymes that hydrolyze cellulose, hemicelluloses and other polysaccharides into fermentable sugars suitable for industrial use. The present study was aimed at molecular, structural and functional characterization of an endoglucanase from the fungus Aspergillus terreus (AtGH12) using different techniques. The gene encoding this enzyme has been cloned and expressed in the filamentous fungus Aspergillus nidulans strain A773. The strain with increased secretion was selected and the enzyme sequence was confirmed by mass spectroscopy MALDI TOF MS. Later, functional studies such as analysis of optimal pH and temperature, thermal stability, suppression and enhance effects of additives were applied to the AtGH12 characterization. The mass spectrometry of hydrolyzed substrate from the enzyme catalysis was acquired as a way to investigate the cleavage pattern of hydrolysis and the study of the enzyme/substrate interaction. Structural characterization of the recombinant enzymes was obtained using techniques such as dynamic light scattering, circular dichroism as well as small angle X-ray scattering and native gel, aided to determine the folding and oligomeric state of AtGH12 in solution. In order to provide support for the development of more effective enzyme cocktails for hydrolysis of lignocellulosic biomass, the activity of AtGH12 was evaluated using sugarcane bagasse pretreated by hydrothermal and organosolv processes. Subsequently, the degree of synergism in this type of substrate was measured using a commercial enzyme cocktail Acellerase®.
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Mamani, Huaman Edgardo. "Bioadsorción del Pb+2 por las biomasas de Aspergillus niger y Aspergillus fumigatus aislados del Callao." Master's thesis, Universidad Nacional Mayor de San Marcos, 2012. https://hdl.handle.net/20.500.12672/12085.
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Publicación a texto completo no autorizada por el autorInvestiga la bioadsorcion del plomo (II) usando como material bioadsorbente las biomasas fúngicas Aspergillus niger y Aspergillus fumigatus aislados del pueblo joven Puerto Nuevo-callao. El material bioadsorbente se obtuvo de las muestras tomadas de la zona contaminada del pueblo joven Puerto Nuevo-Callao. El material tratado fue secado en una estufa a la temperatura de 80 °C por 2 horas. Se determinó la bioadsorcion de plomo (II) en solución por las biomasas celular de dos hongos por el método instrumental de espectroscopia de absorción atómica. Los experimentos sobre el efecto del pH en el proceso de bioadsorción de Pb (II) por las biomasas fúngicas demostraron que el pH óptimo es 5.0; así como el experimento del efecto de la temperatura optima por las biomasas fúngicas demostraron una temperatura optima de 25°C para la biomasa fúngicas; la concentración del plomo (II) que presenta la mejor bioadsorcion es a 1000ppm. Del estudio de la cinética del proceso de bioadsorción, se determinó que la biomasa de Aspergillus niger 98% fue más eficiente en la remoción del plomo (II) que el Aspergillus fumigatus 96%. El equilibrio se alcanzó a las 100 minutos del inicio del proceso de bioadsorción logrando un porcentaje de remoción de Plomo (II) para Aspergillus niger 98% y para Aspergillus fumigatus 96%. Se concluye que las biomasas fúngicas remueven eficientemente plomo (II) en solución y pueden utilizarse para descontaminar nichos acuáticos contaminados con este metal.
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Erdmann, Jan-Hendrik [Verfasser]. "Anti-Aspergillus-IgG-Bestimmung zur Vorhersage der pulmonalen invasiven Aspergillose nach allogener Stammzelltransplantation / Jan-Hendrik Erdmann." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2018. http://d-nb.info/1160514801/34.
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Müller, Dirk. "Ribozyme zur Genregulation in Aspergillus giganteus." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974042633.
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